Tesi sul tema "Bamboo materials"
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1
Dixon, Patrick G. (Patrick Gary). "The structure and mechanical behavior of bamboo and bamboo products". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111242.
Abstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 199-215).
Bamboo is a unique lignocellulosic material with considerable potential in sustainable construction. Structural bamboo products are analogous to wood products, such as oriented strand board (OSB), but composed primarily of bamboo elements, as opposed to wood elements. Such products could extend the use of bamboo. The mechanical behavior of structural bamboo products in large part depends on that of bamboo tissue. In this thesis, the structure and mechanical properties of dry bamboo tissue are related. Cellular level models are developed and explored, with a focus on density. Density is a practical parameter: it corresponds to weight, and places bamboo in the broader context of cellular solids. Bamboo tissue is made up of parenchyma and vascular bundles, consisting of sclerenchyma fibers and vessels; the structure can be thought of as a fiber reinforced composite. There is a radial gradient in the volume fraction of vascular bundles as well as the fraction of quite solid sclerenchyma fibers within the vascular bundles, increasing from the inside to the outside of the culm wall. Longitudinal flexural properties (modulus of elasticity MOE and modulus of rupture MOR) and compressive strength increase with increasing sclerenchyma fiber volume fraction, indicating the mechanical importance of these fibers. The density also increases with increasing fiber volume fraction. Thus, these longitudinal mechanical properties increase with density. This suggests that in bamboo tissue density reflects the underlying sclerenchyma fiber volume fraction. For moso bamboo (Phyllostachys pubescens), the extrapolated cell wall longitudinal Young's modulus estimate from tests on small flexural specimens, 39.8 GPa, agrees well with the value of 36.6 GPa obtained from a simple cell wall model for the fibers. From mechanical tests of 3D printed models of bamboo parenchyma, an open-cell foam model seems appropriate for bamboo parenchyma. The densification of bamboo increases the longitudinal flexural properties, but natural bamboo at the same density of densified bamboo has higher properties. A multiscale model for wood OSB is adapted for bamboo OSB based on the natural tissue's structure and properties; this model gives a good description of the modulus of elasticity of bamboo OSB made with internode strands.
by Patrick G. Dixon.
Ph. D.
2
Aijazi, Arfa N. (Arfa Nawal). "Material characterization of Guadua bamboo and the environmental feasibility of structural bamboo products". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/80899.
Abstract (sommario):
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 52-55).
Bamboo has long been used in vernacular construction because of its high strength, rapid growth rate, and global abundance. Bamboo is increasingly being used in contemporary architecture as a sustainable alternative to wood and other building materials. Forming bamboo into a structural composite can improve mechanical performance, durability, and joining, which can open up new structural applications and design possibilities as well as remove the stigma that bamboo is the "poor man's timber". This study aims to characterize the radial and longitudinal variation in the microstructure and mechanical properties of Guadua bamboo (Guadua angustifolia kunth) in order to inform efficient material use in a composite. The study found a linear relationship between the MOE, MOR, and compression strength with density. Through analysis of micrographs, the density was correlated to the area fraction of sclerenchyma fiber sheaths. Results from nanoindentation confirmed that the fiber properties did not vary with position. Further the environmental impact in the form of exhaustion of energy found that processed bamboo had a mechanical advantage over raw bamboo culm and lower energy input in manufacturing but superior performance in comparison to wood composites.
by Arfa N. Aijazi.
S.B.
3
Dagilis, Trevor David. "Bamboo composite materials for low-cost housing". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0015/NQ54407.pdf.
4
Ahmad, Mansur. "Analysis of Calcutta bamboo for structural composite materials". Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28742.
Abstract (sommario):
Land use issues have dramatically changed the timber supply outlook for our nation's forest products industry. Since demand for wood products shows no sign of abating, alternative products must be developed. Bamboo is a very promising alternative raw material for the manufacture of structural composite products. It is fast growing, economical, renewable and abundant throughout the world. Bamboo has physical and mechanical properties that are comparable to many commercial timber species, and thus, may easily be processed using existing technology from the wood-based composites industry. Bamboo can be cultivated in the U.S., and thus has the potential to relieve some of the harvesting pressure from our nation's forestlands. However, the use of specific bamboo species for structural composite products will require a thorough investigation of the material as well as its interaction with other components. Thus, the primary objective of this dissertation is to determine the properties of Calcutta bamboo and its interaction with adhesives. The properties investigated were relative density, dimensional stability, equilibrium moisture content, bending strength and stiffness, tensile strength, pH, buffer capacity, wettability and the adhesive penetration. In addition to this, a prototype bamboo parallel strip lumber (BPSL) was manufactured and tested for its physical and mechanical properties. The relationships among the properties of Calcutta bamboo and the prototype bamboo composite were also investigated. As the result of these investigations, it is concluded that Calcutta bamboo is technically a suitable raw material for structural composite products. This result may also be applicable for the utilization of other bamboo species, thus aiding companies in decisions regarding investment in bamboo plantations and manufacturing facilities in the U.S, Malaysia and other parts of the world. The primary benefits from this research may be the development of new products to serve growing markets, and thereby relieving some of the pressure to harvest forestlands.Ph. D.
5
Gerhardt, Michael R. "Microstructure and mechanical properties of bamboo in compression". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76122.
Abstract (sommario):
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 34).
Bamboo has received much interest recently as a construction material due to its strength, rapid growth, and abundance in developing nations such as China, India, and Brazil. The main obstacle to the widespread use of bamboo as a structural material is the lack of adequate information on the mechanical properties of bamboo. In this work, the microstructure and mechanical properties of Phyllostachis dulcis bamboo are studied to help produce a model for the mechanical properties of bamboo. Specifically, a linear relationship is established between the density of bamboo samples, which is known to vary radially, and their strength in compression. Nanoindentation of vascular bundles in various positions in bamboo samples revealed that the Young's modulus and hardness of the bundles vary in the radial direction but not around the circumference. The compressive strength of bamboo samples was found to vary from 40 to 95 MPa, while nanoindentation results show the Young's modulus of vascular bundles ranges from 15 to 18 GPa and the hardness ranges from 380 to 530 MPa.
by Michael R. Gerhardt.
S.B.
6
Ross, Sheila. "Bamboo construction as a sustainable building technology from a structural and materials engineering perspective". Master's thesis, Faculty of Engineering and the Built Environment, 2021. http://hdl.handle.net/11427/33901.
Abstract (sommario):
The objective of this dissertation is to determine whether bamboo culms or stems are suitable for use as a construction material for permanent structures, from an engineering as well as a sustainability perspective. A secondary objective is to establish whether this would be a suitable building technology for South Africa. The research is desk-top in nature and involves reviewing articles in online journals and publications and collating the information into a coherent form. Eleven species of bamboo commonly used in construction worldwide are selected for investigation of their material and engineering properties. Based on the variations found in the various species of bamboo, approaches to engineering modelling and design of bamboo structures are detailed and discussed. Furthermore, four case studies are presented that illustrate the various areas where bamboo construction is currently used. Finally, research is done regarding the level of the South African bamboo industry, including whether a bamboo species currently exists in South Africa that would be suitable for construction purposes. The preliminary literature review indicated that there is a lack of scientific or structural information regarding bamboo as a building material from an engineering or materials perspective, both globally as well as in South Africa. Although a substantial amount of information was subsequently found on the various aspects of bamboo as a structural material, the information varies widely between sources, which is ascribed to variations in test methods as well as to the location of the species being tested. The design codes and standards from various countries for bamboo design and construction are briefly reviewed. For countries where there is currently no bamboo design code or standard, such as South Africa, it is recommended that the International Standard, ISO 22156, be used as a design basis, using specific material properties relevant to the local species. Many publications state that bamboo is a sustainable building material, comparing favourably with other building materials. However, quantitative proof was found to be either lacking or unclear. Different methods were used in the publications to evaluate bamboo from an environmental perspective, making it difficult to compare and evaluate the different reports and results. However, despite the different methods, it appears that bamboo can be regarded as an environmentally favourable material, provided that local species are used in construction. The four case studies presented demonstrate that bamboo culms are suitable for use in large structures, such as bridges or trusses, as well as for smaller structures such as buildings or houses. They also illustrate the issues that can occur if the design intent is not understood or correctly carried out during construction. South Africa has one bamboo species considered suitable for construction, namely Bambusa balcooa, which is grown in various parts of the country. The properties of the South African plants have not been established as yet. However, theoretical engineering and material properties as determined elsewhere in the world indicate that this is a viable construction material. Further areas of research are the establishment of the material and engineering properties of the local South African bamboo species Bambusa balcooa, as well as further research into the behaviour of bamboo in fire conditions.
7
García, Lina M. (Lina Mariá García De la Ossa). "Radial and longitudinal variation of the mechanical properties of bamboo". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/101858.
Abstract (sommario):
Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 47-48).
Although used for millennia, only recently has there been an increased interest in bamboo as a construction material for its economic, social and environmental benefits. For bamboo to be widely implemented in construction, however, there is a need to better understand the variation in the plant's mechanical properties. The microstructure of bamboo and the mechanical properties of the solid cell wall material of bamboo were characterized for use in models for the variation of the overall mechanical properties of bamboo as a function of radial and longitudinal position. The density of bamboo and the volume fraction of vascular bundles in the bamboo increases with radial position (away from the center of the culm) and decreases with height. Tensile tests follow the trends predicted by the models. Young's modulus and strength increase with radial position (away from the center of the culm). Values for Young's modulus were in the range of 5 to 40 GPa and values for strength varied from 100 to 400 MPa.
by Lina M. Garcia.
S.B.
8
Qian, Jun. "Investigation of crystallization of poly(3-hydroxybutyrate-CO-3-hydroxyvalerates) and their bamboo fiber reinforced composites". Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/J_Qian_120906.pdf.
9
Archila, Santos Hector Fabio. "Thermo-hydro-mechanically modified cross-laminated Guadua-bamboo panels". Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675700.
Abstract (sommario):
Guadua angustifolia Kunth (Guadua) is a bamboo species native to South and Central America that has been widely used for structural applications in small and large-scale buildings, bridges and temporary structures. Currently, its structural use is regulated within seismic resistant building codes in countries such as Peru and Colombia. Nevertheless, Guadua remains a material for vernacular construction associated with high levels of manual labour and structural unpredictability. Guadua buildings are limited to two storeys due to the overall flexibility of the slender and hollow culms and its connection systems. Its axial specific stiffness is comparable to that of steel and hardwoods, but unlike wood, Guadua’s hollow structure and lack of ray cells render it prone to buckling along the grain and to transverse crushing. As a result, Guadua’s mainstream use in construction and transformation into standard sizes or engineered Guadua products is scarce. Therefore, this work focussed on the development of standardised flat industrial structural products from Guadua devising replicable manufacturing technologies and engineering methods to measure and predict their mechanical behaviour. Cross-laminated Guadua panels were developed using thermohydro-mechanically modified and laminated flat Guadua strips glued with a high performance resin. Guadua was subjected to thermo-hydro-mechanical (THM) treatments that modified its microstructure and mechanical properties. THM treatment was applied to Guadua with the aim of tackling the difficulties in the fabrication of standardised construction materials and to gain a uniform fibre content profile that facilitated prediction of mechanical properties for structural design. Densified homogenous flat Guadua strips (FGS) were obtained. Elastic properties of FGS were determined in tension, compression and shear using small-clear specimens. These properties were used to predict the structural behaviour of G-XLam panels comprised of three and five layers (G-XLam3 and G-XLam5) by numerical methods. The panels were assumed as multi-layered systems composed of contiguous lamellas with orthotropic axes orientated at 0º and 90º. A finite element (FE) model was developed, and successfully simulated the response of G-XLam3 & 5 panels virtually loaded with the same boundary conditions as the following experimental tests on full-scale panels. G-XLam3 and G-XLam5 were manufactured and their mechanical properties evaluated by testing large specimens in compression, shear and bending. Results from numerical, FE predictions and mechanical testing demonstrated comparable results. Finally, design and manufacturing aspects of the G-XLam panels were discussed and examples of their architectural and structural use in construction applications such as mid-rise buildings, grid shells and vaults are presented. Overall, this research studies THM treatments applied to Guadua in order to produce standardised engineered Guadua products (EGP), and provides guidelines for manufacturing, testing, and for the structural analysis and design with G-XLam panels. These factors are of key importance for the use of Guadua as a mainstream material in construction.
10
Srikar, V. T. (Vengallatore Thattai) 1972. "Electromigration behavior and reliability of bamboo Al(Cu) interconnects for integrated circuits". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85249.
11
Ellison, Rachel (Rachel M. ). "Mode II fracture mechanics of moso bamboo for application in novel engineering materials". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98653.
Abstract (sommario):
Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 32-34).
Bamboo has been used as a structural material for thousands of years. Recently there has been increasing interest in its use as a modem construction material. In this study, as part of a larger project to characterize the mechanical properties of Moso bamboo for application in the production of structural bamboo products (SBP), end-notched flexure (ENF) tests and three-point bending tests were performed to obtain the mode II interlaminar toughness (GIIc) and longitudinal Young's modulus (EL). It was found that known values for GIIc, include the pith (innermost layer) and cortex (outermost layer) of the bamboo culm in their calculations. The resulting value is, to a statistically significant degree (t = 5.0 x 10⁶), higher than that with the pith and cortex removed, as they typically will be in processing SBP. A new value, GIIc, = 630 +/- 155 J/m² , was established for specimens lacking the pith and cortex. Although no correlation was found between GIIc, and specimen density, it is suspected that a relationship does exist, and recommendations for further investigation are given.
by Rachel Ellison.
S.B.
12
Gough, Katherine. "From bamboo to bricks : self-help housing and the materials industry in urban Colombia". Thesis, University College London (University of London), 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416491.
13
Gu, Xingxing. "Environmentally-benign, Porous and Conductive Carbon Materials for Lithium-Sulphur Batteries". Thesis, Griffith University, 2017. http://hdl.handle.net/10072/366860.
Abstract (sommario):
Materials engineering and nano-manipulation play a key role in the development of advanced Lithium-Sulphur (Li–S) batteries in terms of energy and power density (both gravimetric and volumetric), cycling stability, rate capability, safety and the cost of production. In this thesis, two strategies are used to address the demands, i.e. fabrication of low cost, environmentally benign and conductive carbon-sulphur (C−S)
nanostructured cathodes, and the use of interlayers as a novel battery configuration in Li–S battery systems.
In the first strategy, inexpensive, scalable, environmentally-friendly and commercial bamboo biochar was activated via a KOH/annealing process to create an abundant microporous structure. This was then used to encapsulate sulphur to prepare a microporous bamboo carbon–sulphur (BC-S) nanocomposite as the cathode for Li–S batteries. The bamboo carbon micropores can encapsulate sulphur and polysulphides
to reduce the shuttle phenomenon during cycling while simultaneously maintaining electrical contact between the sulphur and the conductive carbon framework during the charge/discharge process. The treated BC-S (T_BC-S) nanocomposite with 50 wt% sulphur content delivers a high initial capacity of 1295 mA·h·g−1 at a low discharge rate of 160 mA·g−1 and high capacity retention of 550 mA·h·g−1 after 150 cycles at a high discharge rate of 800 mA·g−1 with excellent coulombic efficiency (≥ 95%).Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
14
Chan, Cameron D. "MECHANICAL OPTIMIZATION AND BUCKLING ANALYSIS OF BIO-COMPOSITES". DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/877.
Abstract (sommario):
Today’s environmental concerns have led a renewed search in industry to find new sustainable materials to replace non-renewable resources. President Barack Obama also quoted in the recent 2012 Presidential Debate “that there is a need to build the energy sources of the future and invest in solar, wind, and bio-fuels.” Bio-composites are believed to be the future and the new substitute for non-renewable resources. Bio-composites are similar to composites in that they are made up of two constituent materials; however the main difference is that bio-composites are made from natural fibers and a biopolymer matrix. This research investigates the buckling behavior of bamboo and will analyze and determine the slender ratio that will induce buckling when bamboo is used as a column. Along with the investigation of the bamboo under buckling, this study will also show the potential of bio-composites to replace non-renewable resources in industry through experimental and numerical analysis. However, in order to study the buckling behavior of the bamboo, the mechanical characteristics of the bamboo and optimal curing treatment first had to be established. This is because, in order for bamboo to acquire proper strength characteristics, the bamboo must first be treated.
Due to the scarcity of bamboo material in the lab, the obtainment of the mechanical properties of the bamboo as well as the optimal curing treatment was done in collaboration with Jay Lopez. In order for bamboo to acquire proper strength characteristics, the bamboo must be treated. In the first study, a total of four different types of natural treatments were analyzed to optimize the mechanical characteristics of bamboo. To assess each curing method, tensile and compression tests were performed to obtain the mechanical properties. Due to each bamboo culm having different thicknesses and cross sections, the specific strength property is used to normalize the data and allow for easy comparison and assessing of each curing method equally. The specific strength parameter is defined as the ultimate stress divided by the density of the material. These curing treatments consisted of four thermo-treatments, three different percentages of salt treatments, one lime treatment, and one oil treatment. The thermo-treatments consisted of heating the bamboo internodes in an autoclave with no pressure at 150oF, 180°F, 200°F, and 220°F. The experimental results of the thermo-treatments determined that bamboo obtains higher mechanical properties as well as reduced weight when heated at higher temperatures. This is explained by the increasing bound water extracted from the bamboo material at higher temperatures. In addition to finding the optimal heat treatment, the internodes of bamboo were soaked in natural additives that included a 3%, 6%, and 9% Instant Ocean sea salt solution, a Bonide hydrated lime solution, and a Kirkland canola oil solution for approximately five days and then heat treated at the optimal temperature of 220°F. The experimental results showed that all of the different additives had a significant effect on the mechanical properties.
After determining the mechanical properties of each curing method, the results were then analyzed through a trade study. The trade study parameters consisted of weight-drop of the material, the specific strength, and the ultimate stress for both compression and tension. Each parameter of the trade study is kept unbiased as the weighting of each parameter is set equal to each other. The results of the trade study indicated that the 3% salt solution was the optimal curing treatment, yielding a higher specific strength value for both compression and tension, along with a significantly lower weight-drop after curing.
After we came up with the optimal treatment, the buckling behavior of bamboo was investigated. The buckling analysis was investigated to determine at what slenderness ratio the bamboo would buckle when used as a column. A total of seven cases were investigated using different lengths, that ranged from 1.5” to 10”. Through experimental results, it was determined that a slenderness ratio above approximately 34.7 would induce global buckling to the bamboo column.
The last investigation of this study consisted of building a small prototype wall structure using bio-composites. The prototype wall structure was manufactured using a combination of bamboo and a bi-directional woven hemp fabric. The dimensions of the prototype were 15.13” long and 7.75” tall. The wall structure was tested under compression in the Aerospace Structures/Composites Lab and the Architectural Engineering Department’s high bay laboratory. The results of the experimental test on the wall showed great potential for bio-composites, as the structure withstood a force of 46,800 pounds.
A numerical analysis technique was also employed through the finite element method using the Abaqus software. The purpose of the finite element method was to validate the experimental results by comparing the buckling behavior of the tests. The numerical analysis showed very good agreement with the experimental results.
15
Matsuoka, Jéssica Harue. "Avaliação da eficiência do ácido pirolenhoso no tratamento preservativo de taliscas de bambu gigante contra a deterioração por fungos". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256852.
Abstract (sommario):
Orientador: Antonio Ludovico BeraldoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
Made available in DSpace on 2018-08-19T15:40:14Z (GMT). No. of bitstreams: 1 Matsuoka_JessicaHarue_M.pdf: 8291603 bytes, checksum: 8efcc65849d53bfd555a92bc8450b072 (MD5) Previous issue date: 2011
Resumo: O bambu apresenta inúmeras características que o qualificam como um material versátil e que há milhares de anos vem servindo como matéria-prima para diversos fins, fazendo parte da história e da cultura de muitos povos. Muitas pesquisas vêm sendo realizadas acerca da utilização do bambu em setores diversos como da construção civil, movelaria e produção de celulose, visando à promoção de um desenvolvimento mais sustentável. Por se tratar de um recurso renovável, o uso do bambu tem o potencial de minimizar os impactos negativos ao meio ambiente e reduzir os custos da produção, além de apresentar excelentes propriedades físico-mecânicas. Dentre as espécies cultivadas no Brasil, o bambu gigante (Dendrocalamus giganteus Munro), de origem asiática, destaca-se na utilização para construção civil, em aplicações estruturais, arquitetônicas e em movelaria. No entanto, a baixa resistência natural da maioria das espécies ao ataque de organismos xilófagos é ainda uma das principais limitações ao seu uso, implicando em graves prejuízos econômicos. Por este motivo, muitos tratamentos preservativos vêm sendo desenvolvidos, com o intuito de prolongar a vida útil do bambu e aumentar sua resistência contra os agentes deterioradores. Este trabalho teve como objetivo identificar os principais gêneros de fungos deterioradores de bambu e desenvolver um método de tratamento preservativo que fosse eficiente no controle da deterioração do bambu por fungos e que minimizasse as características negativas inerentes aos tratamentos químicos ora existentes e ao impacto ambiental por eles causado. Desta forma, investigou-se a possibilidade de utilização do ácido pirolenhoso, produto obtido a partir do processo de carbonização de matéria vegetal. Foram testadas diversas concentrações e tempos de tratamento e realizados ensaios de apodrecimento acelerado em laboratório e ensaios não destrutivos e destrutivos para verificação da eficiência no controle à degradação por fungos. Os gêneros de fungos foram previamente isolados e identificados em ensaios de simulação de exposição em campo. Pela análise estatística dos resultados não houve diferença significativa entre os corpos-de-prova tratados e não tratados. Devido ao limitado período de 16 semanas de duração do ensaio, não foi possível avaliar a ação protetora do ácido pirolenhoso, nas concentrações e tempos de imersão utilizados, quanto à sua eficiência no tratamento preservativo das taliscas de bambu gigante contra deterioração por fungos
Abstract: Bamboo can be considered as a versatile material because of its many features and so it has been used for thousands of years serving as raw material to numerous uses, being part of many people's history and culture. Many researches have been conducted about bamboo uses in several areas, such as construction, furniture making and cellulose production, with the objective to promote a sustainable development, in which bamboo can substitute the conventional materials, especially wood. As bamboo is a renewable resource, it can reduce the negative impact to environment, minimize costs and also presents excellent physical and mechanical properties. There are many cultivated species in Brazil, such as the giant bamboo (Dendrocalamus giganteus Munro), an Asian specie that is largely used on construction, in structural and architectural applications and to furniture production. However, most species of bamboo has low natural resistance to the wood decay organisms, which still constitutes one of the major limitations to its use and can cause several economic damages. For this reason, many preservative treatments have been developing, aiming to increase bamboo life cycle and its resistance against decay agents. This work had as objective to identify the main genera of wood decaying fungi and develop an efficient preservative treatment method that controls fungal bamboo decay and minimize the negative features intrinsic to existing chemical treatment and the environmental impact caused by them as well. It was investigated the possibility of using a pyroligneous acid, which is obtained from the vegetal coal production process. Several concentrations and time of treatment were tested and specimens were submitted to an accelerated decay test in laboratory and non-destructive and destructive tests to verify the product efficiency against fungi decay. Fungi genera were previously isolated and identified through a test that simulated field exposure. The statistical analysis from the results indicated no significant difference between treated and non-treated specimens, however, due to the short period of 16 week of the essay, it wasn't possible to evaluate the protective activity of pyroligneous acid, for the concentrations and times of treatment applied to the strips, about its efficiency on preservative treatment against bamboo fungi decay
Mestrado
Construções Rurais e Ambiencia
Mestre em Engenharia Agrícola
16
Ballesté, Joan Font. "Desempenho construtivo de estruturas de cobertura com colmos de bambu". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/16/16132/tde-21122017-103248/.
Abstract (sommario):
O foco desta pesquisa é o estudo do desempenho de colmos de bambu em estruturas de cobertura. A arquitetura do século XXI precisa de novos modelos de produção e novos materiais para possibilitar o desenvolvimento sustentável do planeta. O bambu é um material renovável, com custos de produção baixo, pegada ecológica positiva e de qualidade física excelente; mas existe um desconhecimento bastante generalizado sobre o seu uso na construção civil. Esta lacuna é ainda maior quando se procura entender seu comportamento estrutural ao longo do tempo. Entre os vários requisitos para avaliar o desempenho do material, quando é o elemento portante de uma construção, destacam-se dois que são essenciais: a estabilidade e a durabilidade. Neste trabalho procura-se, em primeiro lugar, compreender o comportamento físico-mecânico do material na composição microscópica e macroscópica para delimitar sua segurança estrutural, e em segundo lugar, examinar aqueles processos que, desde o crescimento da planta até à sua utilização em obra, determinam a vida útil do material. São também analisadas as práticas construtivas e ações de projeto que condicionam transversalmente estas duas exigências de desempenho, junto com um levantamento de estudos de caso que visa criar novos critérios de design de estruturas e soluções construtivas. Esta pesquisa procura expor os pontos fortes e fracos da atual construção com bambu, para que os primeiros sejam potencializados e os segundos sejam corrigidos.The focus of this research is the study of the performance of bamboo in coverage structures. The architecture of the 21st century needs new production models and new materials to enable the sustainable development of the planet. Bamboo is a renewable material, with low production costs, positive ecological footprint and excellent physical-mechanical properties; but there is a rather general lack of knowledge about its use in civil construction. This gap is even greater when one tries to understand its structural behaviour over time. Among the various requirements to evaluate the performance of the material, when it is the structural element in a construction, two that stand out are essential: stability and durability. In this work, the understanding of the physical and mechanical behaviour of the material in the microscopic and macroscopic composition is sought first to delimit its structural safety, and secondly, examining the processes that, since the plants\'s growth until its usage in work, determine the useful life of the material. It is also analyzed the constructive practices and project actions that condition transversally these two performance requirements, along with a survey of case studies that aim to create new criteria of structure design and building solutions. This research seeks to export the strengths and weaknesses of the current construction with bamboo, so the first may be potentialized and the latter corrected.
17
Miskalo, Eugênio Polistchuk. "Avaliação do potencial de utilização de bambu (Dendrocalamus giganteus) na produção de painéis de partículas orientadas". Universidade Tecnológica Federal do Paraná, 2009. http://repositorio.utfpr.edu.br/jspui/handle/1/182.
Abstract (sommario):
O consumo de painéis de madeiras reconstituídas tem se tornado crescente, implicando, por conseqüência, na utilização de madeiras oriundas de reflorestamentos, tradicionalmente de Pinus e Eucalyptus, constituídos por fibras longas e curtas respectivamente, exigindo a ampliação e a reposição de áreas de plantios de forma acelerada. Neste trabalho, o objetivo é avaliar o potencial da utilização de bambu como alternativa para fabricação de painéis de partículas orientadas – OSB (Oriented Strand Board). A espécie de bambu estudada foi o Dendrocalamus giganteus, constituída por fibras médias. Foram produzidos painéis com teores de 4, 6 e 8% de resina à base de fenol-formaldeído. A parte experimental foi dividida em duas etapas. A primeira teve por finalidade conhecer a variação de densidade com a altura relativa do bambu, de forma a separar partículas com características distintas, e proceder a escolha da parte do colmo com densidade mais próxima da indicada por MALONEY, a fim de confeccionar os painéis com características similares às de OSB de Pinus, utilizando a mesma técnica de fabricação. Para a segunda etapa foi utilizado um planejamento experimental para a obtenção de painéis de bambu com partículas com duas orientações de corte e três quantidades de adesivo. Os ensaios físicos e mecânicos dos painéis foram executados em conformidade com as normas EN 300/93 européia e ASTM 1037-1996, americana. Os resultados indicaram que painéis feitos com o corte do bambu na direção tangencial com 6% de resina é o mais adequado para a produção em escala, visto o seu maior rendimento e ao seu comportamento mecânico ser comparável ao de OSB comercial, segundo as normas citadas.The consumption of restored wood boards has increased, bringing along the use of woods derived from reforestation, traditionally from Pinus and Eucalyptus, composed of long and short fibers respectively, which demand the enlargement and replacement of the plantation areas quickly. In this essay, the main objective was to measure the potential application of the bamboo as an alternative to make boards of Oriented Strand Board – OSB. The kind of bamboo studied was the Dendrocalamus giganteus, which is made of medium strands. Boards were produced with 4, 6 and 8% contents of phenol-formaldehyde resin. The experimental work was divided in two stages. The purpose of the first stage was to study the variation of density and the relative highness of the bamboo studied, in order to separate particles with different characteristics, and proceed the selection of the stem part with density more similar to the one indicated by MALONEY, with the purpose of making boards with similar characteristics to Pinus OSB boards, using the same production technique. On the second stage, experimental planning was applied to obtain bamboo boards of particles with two slit orientation and three numbers of adhesive. The physical and mechanical tests were performed according to the European patterns EN 300/93 and American patterns ASTM 1037-1996. The results indicated that the boards made in bamboo at the tangential direction at 6% of resin is the most appropriate to produce on a large scale, considering that its yield and mechanical behavior is comparable to commercial OSB, in agreement to quoted patterns.
18
Knowlton, Brett D. (Brett Douglas). "The effects of grain structure and Cu distribution on the relability of near-bamboo Al-Cu alloy interconnects". Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10379.
19
ADNAN, ALI MUHAMMAD, e SARWAR MUHAMMAD IMRAN. "Sustainable and Environmental freindly fibers in Textile Fashion (A Study of Organic Cotton and Bamboo Fibers)". Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20137.
Abstract (sommario):
In recent times sustainability is a leading characteristic of textile fashion products. Textile fashion companies are focusing more on sustainable products these days, so that they can meet the environmental and social aspects. For getting competitive advantage in fashion business the companies have to take care of social, political and economical issues, and they must be aware of current trends of the market. Sustainable fibres provide solution for the companies facing issues regarding environmental problems; these fibres are also favorable to meet the market demands of quality products these days. The main objective of this report is to use the sustainable materials in fashion garments; the report contains rich information about two natural sustainable fibres (organic cotton and Bamboo), that describes the brief history, biography, development, processing, application and uses of these fibres. This report briefly describes the advantages and disadvantages of these fibres and underlines the usage of these fibres by famous designers, and by many top brands and fashion companies for their competitive advantage and brand image. The report highlights the potentials of using these materials in textile fashion products and describes that high fashion and quality products can be made by these products to guarantee the environmental and social standardsProgram: Magisterutbildning i Applied Textile Management
20
Barros, Andréa Carla de Almeida. "Estudos Sobre o Potencial do Bambu Guadua angustifolia Kunz. Para a Fitorremediação dos Metais Pesados Zinco e Cádmio". Universidade Federal de Alagoas, 2007. http://repositorio.ufal.br/handle/riufal/1067.
Abstract (sommario):
Phytoremediation is considered to be an economically promising and an
ecologically correct technology for the removal of toxic materials from the environment
since it employs natural physico-chemical and biochemical processes for the clean up of
degraded areas. Guadua angustifolia (Bambusoideae, Poacea), a bamboo that is native in
Central and South America and which presents tall, robust and prickly culms, shows
considerable potential in the phytoremediation of toxic metals for the following reasons: a)
it presents an extraordinary capacity for multiplication and vegetative reproduction; b) it is
efficient at fixing CO2 from the atmosphere, thus contributing to the reduction in the socalled
'greenhouse effect'; c) it is not part of the human food chain; d) it presents
ornamental traits that can be used to advantage in the landscaping of polluted areas, such as
those previously occupied by landfills; and e) the aerial biomass may be used either in civil
construction or in the furniture industry after completing its phytoextractive function. The
objective of the present study was to investigate the potential of G. angustifolia for the
phytoremediation of zinc and cadmium. The absorption and translocation of these metals
from roots to leaves, together with their distribution in the different tissues, were analysed.
Additionally, the production of metal transporter proteins (phytochelatins) and the
formation of complexes between metals and low molecular weight organic compounds
were investigated. The experiments were conducted in hydroponic and soil conditions. Soil
that had been artificially contaminated with zinc or cadmium sulphate solutions, was
distributed in perforated plastic bags. Bamboo shoots, previously maintained in vermiculite,
were transplanted to the contaminated soil and kept in the greenhouse at room temperature
for 180 days with periodical watering. The washed plants were dried at room temperature
and root, culm, leaf and soil samples were digested with a mixture of nitric and perchloric
acids (3:1; v/v) for 3 h at room temperature and for 3 4 h at 120°C. The determination of
zinc and cadmium in the samples was performed using atomic absorption spectroscopy at
213.9 and 228.8 nm respectively. Based on the absolute average concentration values, the
bioconcentration and translocation factors (BCF and TF, respectively) were calculated. The
accumulation of metals in organs of the plants cultivated in contaminated soil followed the
order roots > culms > leaves. The accumulation of zinc in the roots was 57.2% (2720
mg/kg dry weight), whilst in the aerial parts it was 42.8% (2032 mg/kg). The accumulation
vii
of cadmium in the roots was 79.9% (770 mg/kg), whilst in the aerial parts it was 20.1%
(194 mg/kg). Thus, G. angustifolia fulfils one of the criteria employed to define
hyperaccumulator plants in that the concentration of zinc in the aerial parts of plants grown
in contaminated substrate was approximately 20.2-fold higher than the average value found
in plants grown under control (non-polluted) conditions, whilst the concentration of
cadmium was 194-fold higher than the control value. Further analyses showed that the
concentration of zinc in contaminated soil that had supported the cultivation of bamboo was
reduced by 65.5%, whilst the level of cadmium was reduced by 60.2%. The high values of
BCF (> 1) related to zinc indicated that the roots and aerial tissues had not attained
saturation and/or that the transport systems were still active under the experimental
conditions employed such that even larger quantities of metal could be absorbed and
transported. Regarding cadmium, the values of BCF indicated that saturation and/or
inactivation of roots had not been attained, as in the case of zinc, whereas this was not valid
for the aerial tissues. TF values for both metals were low (< 1) indicating that zinc and
cadmium transport in G. angustifolia tissues was not very efficient. One of the greatest
obstacles to the use of G. angustifolia in phytoremediation of these metals appears to be
related to the translocation in the tissues, mainly from culms to leaves. Although this aspect
limits the applicability of G. angustifolia in the phytoremediation of zinc and cadmium, it is
clear that this species offers significant potential since the larger portion of its biomass is
represented by the culms. Such potential could be exploited by using appropriate
agronomic techniques in order to allow the growth of plants in polluted soils, and genetic
engineering technology to facilitate the mobility of metals from roots to shoots.Fundação de Amparo a Pesquisa do Estado de Alagoas
A fitorremediação é considerada uma tecnologia economicamente promissora e ecologicamente correta porque utiliza processos físico-químicos e bioquímicos naturais para a limpeza de áreas degradadas. A Guadua angustifolia (Bambusoideae, Poacea), um bambu nativo da América do Sul e Central, que apresenta colmos robustos, altos e espinhosos, apresenta considerável potencial para a fitorremediação de metais tóxicos pelas seguintes razões: a) possui extraordinária capacidade de multiplicação e reprodução vegetativa; b) pode resgatar CO2 da atmosfera eficientemente, contribuindo para a diminuição do chamado 'efeito estufa'; c) não faz parte da cadeia alimentar; d) possui atributos ornamentais que podem ser utilizados no paisagismo de áreas poluídas, como aquelas previamente ocupadas pelos lixões; e) a biomassa aérea pode ser aproveitada na construção civil ou na indústria moveleira, após cumprido o papel fitoextrator. O objetivo do presente estudo foi investigar o potencial da G. angustifolia para a fitorremediação dos metais pesados zinco e cádmio. Os processos de absorção e translocação dos metais das raízes para as partes aéreas e sua distribuição nos diferentes tecidos foram analisados. Além disso, a produção de proteínas transportadoras de metal (fitoquelatinas) e a formação de complexos de metal com compostos orgânicos de baixo peso molecular foram investigados. Os experimentos com G. angustifolia foram conduzidos tanto em condições hidropônicas, quanto no solo. O solo artificialmente contaminado com soluções de sulfato de zinco ou cádmio foi distribuído em saquinhos de plástico perfurados. As mudas de bambu, previamente mantidas em vermiculita, foram transplantadas para o solo contaminado e conservadas na casa de vegetação, à temperatura ambiente, durante 180 dias, com regas periódicas. As plantas foram então lavadas e dessecadas à temperatura ambiente e as amostras de raízes, colmos, folhas e solo foram digeridas com uma mistura de ácido nítrico e ácido perclórico (3:1; v/v) durante 3 h à temperatura ambiente e posteriormente por 3 a 4 h à 120 °C. A determinação da concentração de zinco e cádmio nas diferentes amostras foi realizada através de espectroscopia de absorção atômica a 213,9 e 228,8 nm respectivamente. Com base nos valores médios absolutos da concentração, os fatores de bioconcentração (FBC) e de translocação (FT) foram calculados. O acúmulo de zinco e cádmio nas plantas cultivadas no solo obedeceram à ordem raízes > colmos > folhas. O acúmulo de zinco nas raízes do bambu foi de 57,2% (2720 mg/kg peso seco), enquanto que v nas partes aéreas foi de 42,8% (2032 mg/kg peso seco). O acúmulo de cádmio nas raízes foi de 79,9% (770 mg/kg) e nas partes aéreas foi de 20,1% (194 mg/kg). As análises demonstraram que ocorreu uma redução de 65,5% na concentração de zinco e 60,2% na concentração de cádmio, no solo contaminado, após o cultivo com bambu. No que diz respeito ao zinco, os altos valores de FBC (> 1) indicaram que as raízes e os tecidos aéreos ainda não haviam sido saturados e/ou os sistemas de transporte ainda estavam ativos nas condições experimentais empregadas e uma quantidade ainda maior de metal poderia ser absorvida e transportada. Com relação ao cádmio, os valores de FBC indicaram que ainda não havia ocorrido saturação e/ou a inativação dos sistemas de transporte nas raízes, ao contrário dos tecidos aéreos que já se encontravam saturados. Os valores de FT para ambos os metais foram baixos (< 1) indicando que o sistema de transporte de zinco e cádmio nos tecidos da G. angustifolia não são muito eficientes. Assim, a G. angustifolia atende um dos um dos critérios usados para definir plantas hiperacumuladoras, em que a concentração de zinco nas partes aéreas das plantas desenvolvidas em substrato contaminado foi aproximadamente 20.2 vezes maior do que o valor médio encontrado em plantas desenvolvidas em solos não poluídos, enquanto que a concentração de cádmio foi 194 vezes maior. Outras análises mostraram que a concentração de zinco no solo contaminado, que havia sido cultivado com bambu, foi reduzida em 65,5%, enquanto que o nível de cádmio foi reduzido em 60,2%. Um dos maiores obstáculos ao emprego da G. angustifolia para a fitorremediação desses metais parece estar relacionado com a translocação nos tecidos, principalmente dos colmos para as folhas. Embora esses aspectos limitam a aplicação da G. angustifolia na fitorremediação do zinco e cádmio, podemos afirmar que essa espécie apresenta grande potencial, visto que a maior parte da biomassa da planta é representada pelos colmos. Esse potencial poderia ser explorado através do uso de técnicas agronômicas adequadas para viabilizar o crescimento das plantas em solos poluídos e de técnicas de engenharia genética para facilitar a mobilidade dos metais das raízes para as folhas.
21
Lopez, Jay. "Optimizing the Mechanical Characteristics of Bamboo to Improve the Flexural Behavior for Biocomposite Structural Application". DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/902.
Abstract (sommario):
Global awareness and preservation have spurred increasing interest in utilizing environmentally friendly materials for high-performance structural applications. Biocomposites pose an appealing solution to this issue and are characterized by their sustainable lifecycles, biodegradable qualities, light weight, remarkable strength, and exceptional stiffness. Many of these structural qualities are found in applications that exhibit flexural loading conditions, and this study focuses on improving the bending performance of engineered biocomposite structures. The current application of biocomposites is increasing rapidly, so this expanding research explores other natural constituent materials for biocomposite structures under flexural loading.
The renewable material investigated in this study was experimentally and numerically validated by optimizing the mechanical characteristics of bamboo fibers in biocomposite structures under flexural loading conditions through various thermal and organic chemical treatment methods. Therefore, bending performance of a biocomposite truss and I-beam are analyzed to demonstrate the benefits of utilizing optimally treated bamboos in their design.
To accomplish this goal, the first task consisted of treating bamboos by thermal and chemical means to determine the resulting effects on the compressive and tensile mechanical properties through experimental testing. Results indicated a significant improvement in strength, stiffness, and weight reduction. An extensive analysis determined the optimal treatment method that was utilized for flexural loading conditions.
The second task entailed studying the flexural behavior of the optimally treated bamboo in two geometric configurations, a hollow cylinder and veneer strip, to determine the resultant properties for the truss and I-beam structure. The effect of node location on flexural performance was also studied to establish design guidelines for the applied structures. Bending tests indicated that node location affects the strength and stiffness of the hollow cylindrical configuration but has minimal effects on the veneer strip. Observations discovered by this study were employed into the designs of the applied structures that yielded excellent mechanical performance through flexural testing.
The final task required conducting a finite element analysis in Abaqus/CAE on the performance of each structural application to validate experimental results. A conclusive analysis revealed good agreement between the numerical method and experimental result.
22
Ostapiv, Fabiano [UNESP]. "Resistência mecânica do material compósito: madeira de eucalipto-lâmina de bambu". Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/103757.
Abstract (sommario):
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Tanto o bambu como o eucalipto são importantes recursos florestais. As lâminas de bambu gigante, contínuas, largas e finas obtidas por processo de torneamento são um excelente material para revestir e reforçar madeira e painéis sarrafeados de eucalipto. Neste trabalho foram realizados ensaios de cisalhamento e tração normal na madeira de eucalipto de alta densidade com e sem o revestimento com lâminas de bambu. Foram produzidos painéis sarrafeados colados lateralmente (EGPs) de Eucalyptus saligna que foram ensaiados à flexão estática e a tração normal, segundo a norma NP EN 310, no sentido transversal do painel em que as ripas são coladas lateralmente. Verificou-se que as lâminas de bambu funcionaram como reforço mecânico para os casos de tração normal na madeira de eucalipto, mas que não houve reforço quando sujeita a esforços cisalhantes, independentemente da posição dos anéis de crescimento da madeira nas amostras. Neste caso as lâminas funcionaram apenas como revestimento. Verificou-se um comportamento frágil do painel sarrafeado de eucalipto durante sua ruptura a flexão no sentido transversal. Foram repetidos os ensaios para os painéis sarrafeados de eucalipto revestidos com lâminas de bambu gigante em dupla face. Verificou-se então um grande aumento na resistência mecânica à flexão estática no painel laminado. Com o reforço das lâminas houve uma mudança no comportamento do painel que deixou de romper de forma frágil passando a romper de modo dúctil, tornando o painel mais elástico e confiável ao uso. Além disso, foram estudadas as características de acabamento superficial das lâminas de bambu quando o material é submetido a processos de lixamento manual
Both bamboo and eucalyptus wood are important forest resources. The giant bamboo veneers continuous, wide and thin obtained by turning process are an excellent material for cover and reinforce the wood and laths edged glued panels (EGP) of Eucalyptus saligna. In this work was tested the eucalyptus wood of high density to shear and normal traction, then the eucaliptus wood was covered with layers of bamboo veneer and so repeated the same mechanic tests. Were produced panels EGP of eucalyptus that were tested for static bending, according to NP EN 310, in the direction that the laths are glued. It was found that bamboo veneers acted as mechanical reinforcement for the cases of normal traction in the eucalyptus wood, but there was no increase in eucalyptus wood subjected to shear efforts, regardless of the position of growth rings in wood samples. In this case the veneers functioned only as a coating. There was a fragile behavior of the panel EGP of eucalyptus during their break to shear efforts. The tests were repeated for the panels EGP coated with bamboo venners on double-sided. There was then a large increase in mechanical resistance to bending of laminated panel. With the increase obtained was a change in behavior of the panel that failed through the fragile break so ductile rupture, making the panel more elastic and reliable to use. Furthermore were studied the characteristics of roughness of the surface of bamboo veneer when the material is subjected to manual sanding processes
23
Guimarães, Ricardo José. "Avaliação do uso de bambu como estrutura em alvenaria de blocos de solo-cimento". Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2705.
Abstract (sommario):
A utilização de materiais que envolvam menor quantidade de energia no processo produtivo, que sejam mais facilmente reabsorvidos pela natureza e que gerem menos poluentes e resíduos é de grande interesse para o futuro do planeta e de seus habitantes. Neste trabalho são apresentados temas da área da sustentabilidade para a construção civil, como as potencialidades e viabilidade técnica de um material emergente no Brasil, o bambu, que se encaixa perfeitamente na questão, pois é um material que detém boas propriedades de engenharia e com grande disponibilidade no meio rural. Além deste, os blocos de solo-cimento, tão bem empregados em edificações atuais, também destinados às construções sustentáveis, fazem parte da pesquisa. Em um experimento que pretendeu unir o ensinamento acadêmico com a prática, foi desenvolvido um protótipo de parede em blocos de solo-cimento estruturado com varas de bambu. Como objetivos, a avaliação das resistências dos blocos de solo-cimento à compressão, do bambu à compressão axial e à flexão, e do conjunto paredes de blocos de solocimento/bambu também à compressão, foram os elementos principais da pesquisa. Obtiveram-se resultados de carga de ruptura de 153 kN para as paredes e de tensão normal de ruptura de 7,45 MPa para os blocos de solo cimento nos ensaios de compressão. Nos ensaios de compressão do bambu, os valores obtidos resultaram em tensões normais de ruptura de 119,09 MPa e de 96,21 Mpa para corpos de prova com e sem nós, respectivamente. Os resultados obtidos nos testes desenvolvidos com os materiais separadamente e também do conjunto mostraram que ambos satisfazem perfeitamente ao proposto neste trabalho, o que permite considerar adequada a metodologia utilizada na confecção dos corpos de provas bem como na execução dos ensaios relacionados.The use of materials that involve less energy in the production process, are more easily absorbed by nature and generate less pollutants and waste is of great interest for the future of the planet and its inhabitants. This paper presents themes of sustainability for civil construction, such as the potentialities and technical feasibility of an emerging material in Brazil, bamboo, which fits perfectly in the question, since it is an element that has good engineering properties and with great availability in rural areas. In addition to this, soil-cement blocks, so well used in today's buildings, also intended for sustainable buildings, are part of the research. In an experiment that sought to unite the academic teaching with practice, a prototype of wall in blocks of soil-cement structured with bamboo sticks was developed. The main elements of the research were the evaluation of the strengths of the compression-conditioned soilcement blocks, of bamboo to axial compression and bending, and of the combination of soil-cement / bamboo blocks. Results of 153 kN were obtained for the walls and 7.45 MPa for the soil cement blocks in the compression tests. In the bamboo compression tests, the obtained values resulted in 119.09 MPa and 96.21 MPa for test bodies with and without nodes, respectively. The results obtained in the tests developed with the materials separately and also from the set showed that both perfectly fit the one proposed in this work, which allows to consider adequate the methodology used in the preparation of the test bodies as well as in the execution of the related tests.
24
Ostapiv, Fabiano. "Resistência mecânica do material compósito : madeira de eucalipto-lâmina de bambu /". Guaratinguetá : [s.n.], 2011. http://hdl.handle.net/11449/103757.
Abstract (sommario):
Orientador: Marcos Tadeu Tibúrcio GonçalvesBanca: Manoel Cléber de Sampaio Alves
Banca: Marcos Valério Ribeiro
Banca: Eduardo Mauro do Nascimento
Banca: Ivaldo de Domênico Valarelli
Resumo: Tanto o bambu como o eucalipto são importantes recursos florestais. As lâminas de bambu gigante, contínuas, largas e finas obtidas por processo de torneamento são um excelente material para revestir e reforçar madeira e painéis sarrafeados de eucalipto. Neste trabalho foram realizados ensaios de cisalhamento e tração normal na madeira de eucalipto de alta densidade com e sem o revestimento com lâminas de bambu. Foram produzidos painéis sarrafeados colados lateralmente (EGPs) de Eucalyptus saligna que foram ensaiados à flexão estática e a tração normal, segundo a norma NP EN 310, no sentido transversal do painel em que as ripas são coladas lateralmente. Verificou-se que as lâminas de bambu funcionaram como reforço mecânico para os casos de tração normal na madeira de eucalipto, mas que não houve reforço quando sujeita a esforços cisalhantes, independentemente da posição dos anéis de crescimento da madeira nas amostras. Neste caso as lâminas funcionaram apenas como revestimento. Verificou-se um comportamento frágil do painel sarrafeado de eucalipto durante sua ruptura a flexão no sentido transversal. Foram repetidos os ensaios para os painéis sarrafeados de eucalipto revestidos com lâminas de bambu gigante em dupla face. Verificou-se então um grande aumento na resistência mecânica à flexão estática no painel laminado. Com o reforço das lâminas houve uma mudança no comportamento do painel que deixou de romper de forma frágil passando a romper de modo dúctil, tornando o painel mais elástico e confiável ao uso. Além disso, foram estudadas as características de acabamento superficial das lâminas de bambu quando o material é submetido a processos de lixamento manual
Abstract: Both bamboo and eucalyptus wood are important forest resources. The giant bamboo veneers continuous, wide and thin obtained by turning process are an excellent material for cover and reinforce the wood and laths edged glued panels (EGP) of Eucalyptus saligna. In this work was tested the eucalyptus wood of high density to shear and normal traction, then the eucaliptus wood was covered with layers of bamboo veneer and so repeated the same mechanic tests. Were produced panels EGP of eucalyptus that were tested for static bending, according to NP EN 310, in the direction that the laths are glued. It was found that bamboo veneers acted as mechanical reinforcement for the cases of normal traction in the eucalyptus wood, but there was no increase in eucalyptus wood subjected to shear efforts, regardless of the position of growth rings in wood samples. In this case the veneers functioned only as a coating. There was a fragile behavior of the panel EGP of eucalyptus during their break to shear efforts. The tests were repeated for the panels EGP coated with bamboo venners on double-sided. There was then a large increase in mechanical resistance to bending of laminated panel. With the increase obtained was a change in behavior of the panel that failed through the fragile break so ductile rupture, making the panel more elastic and reliable to use. Furthermore were studied the characteristics of roughness of the surface of bamboo veneer when the material is subjected to manual sanding processes
Doutor
25
Radaik, Carlos Eduardo. "Cadeia produtiva do bambu como material construtivo e sua aplicação: estudos de caso no estado de São Paulo". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/102/102131/tde-31082018-150821/.
Abstract (sommario):
O foco desta pesquisa é o estudo da cadeia produtiva do bambu como material construtivo, investigando atores, atividades e processos. A arquitetura do futuro necessita de novos modelos e materiais construtivos para possibilitar o desenvolvimento sustentável do planeta. A atual demanda habitacional, no Brasil e no mundo, exige do setor da construção civil maior consumo de matériasprimas e, por conseguinte, implicando na elevação da emissão de CO2 e do consumo de energia. Novos materiais que demandam uma quantidade menor de energia em sua produção e uma menor geração de resíduos estão começando a ocupar posição de destaque na cadeia produtiva da construção civil. Neste contexto, o bambu no formato roliço, entre os materiais construtivos do futuro, por suas qualidades físico-mecânicas, além das ambientais, econômicas e sociais, poderia contribuir de maneira positiva. Arquitetos e construtores, no Brasil e em outras partes do mundo, tem de forma significativa ampliado os usos do bambu, aplicando-o em residências, pavilhões, e até em grandes estruturas. Porém, ainda existe um desconhecimento bastante generalizado sobre seu uso na construção civil. Esta lacuna é ainda maior quando se procura entender a sua cadeia produtiva. A compreensão dos atores, processos e da utilização dos materiais não convencionais, como o bambu, para a concepção projetual, é fundamental para o desenvolvimento do estudante e do profissional, seja ele engenheiro ou arquiteto. O trabalho de campo, juntamente ao referencial teórico estudado, permitiu a compreensão de que a cadeia produtiva do bambu como material construtivo além de não seguir o padrão estabelecido na literatura, principalmente com relação aos atores e processos envolvidos diretamente na transformação da matéria-prima, se apresenta de forma desorganizada e frágil, com a concentração de processos em poucos atores, resultando pouca eficiência e dificultando o seu desenvolvimento.The focus of this research is the study of the bamboo productive chain as constructive material, investigating agents, activities and its processes. The architecture of the future needs new models and constructive materials to enable the sustainable development of the planet. The actual housing demand in Brazil and in the world, require from the civil construction sector a larger consumption of raw material and therefore producing a larger emission of CO2 and energy consumption. New materials that demand a smaller amount of energy and its production and a smaller residual generator are beginning to occupy a prominent position in the productive chain of the civil construction. In this context, the bamboo in natura shape is included in the construction materials of the future, because its physical-mechanical component, also environmental, economic and social component that could contribute in a positive manner. Architects and constructors, in Brazil and in other parts of the world, have considerably increased the use of bamboo; using it in residences, warehouses and even in large structures, although there is a widespread ignorance about its use in the civil construction. This gap is even larger when one seeks to understand its productive chain. The comprehension of its agents, processes and the use of non-conventional materials, such as bamboo, for a project conception is fundamental for the student and the professional development, whether an engineer or architect. The fieldwork, along with the theoretical referential studied, allowed the comprehension of the bamboo productive chain as a constructive material, besides to not follow the established standard in the literature, mainly with the relationship between agents and its processes involved directly in the transformation of the raw material, it presents in a unorganized and frail form, with a concentration of processes within few agents, resulting in little efficiency and hindering its development.
26
Palombini, Felipe Luis. "Design de estrutura biônica através de prototipagem e análise por elementos finitos baseada em microtomografia do bambu". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/153296.
Abstract (sommario):
O bambu é considerado um dos materiais naturais com a melhor relação resistência por peso. Entre as características responsáveis encontram-se os feixes fibrosos do esclerênquima, que protegem os elementos de condução de água e solutos na planta, além de serem preenchidos pelo parênquima. Os feixes estão distribuídos gradual-mente, da parte interna à externa do bambu, aumentando a rigidez do colmo. Contudo, a morfologia da seção dos feixes fibrosos e a presença da matriz parenquimática no caule ainda não foram totalmente estudados, quanto à sua importância estrutural, nem aplicados em estruturas biônicas. Esse estudo trata do design de estruturas biônicas baseada na caracterização do bambu, por meio de técnicas não-invasivas, de proto-tipagem e de análise por elementos finitos. Um protocolo de amolecimento e secagem para secionamento foi seguido em uma amostra de bambu (Bambusa tuldoides Munro). A superfície da amostra foi analisada por microtomografia computadorizada de raios X de alta resolução. As imagens resultantes permitiram a segmentação dos tecidos constituintes e caracterização em nível celular. Os modelos 3D do parênquima e do esclerênquima foram discretizados para uma análise por elementos finitos não-linear. Os resultados mostraram que o parênquima é configurado como uma matriz celular de baixa densidade e que distribui as tensões em todos os elementos de re-forço na planta, sendo considerado um tecido com importante função estrutural. De mesmo modo, a geometria da seção dos feixes fibrosos apresentou um desempenho mecânico superior às seções referenciais. Ambas características foram aplicadas no desenvolvimento de duas estruturas biônicas, sendo analisadas como mais eficientes em comparação a um modelo da literatura, e impressas em 3D para análise visual.Bamboo is considered one of the natural materials with the best strength-to-weight ratio. Among the features responsible for its properties are the sclerenchyma’s fiber bundles that protect the conducting elements of water and solutes in the plant, and are filled by parenchyma. Bamboo fibers are gradually distributed from the inner to the outer side of the plant, thus increasing the culm stiffness. However, the morphology of the section of the fiber bundles and the presence of the parenchymatic matrix in the stem have not been fully studied regarding its structural importance, neither applied in bionic structures. This study addresses the design of bionic structures based on the characterization of bamboo, by means of non-invasive techniques, rapid prototyping and finite element analysis. A bamboo sample (Bambusa tuldoides Munro) was col-lected and softening and drying protocols were followed for proper sectioning. The surface of the sample was analyzed by high-resolution X-ray microcomputed tomog-raphy. Resulting images allowed the segmentation of the sample’s constituent tissues and the characterization at a cellular level. The 3D models of the parenchyma and sclerenchyma were discretized for a non-linear finite element analysis. The results showed that the parenchyma is set as a low-density cellular matrix by distributing the stresses among all reinforcement elements in the plant, being considered a tissue with great structural importance. Likewise, the shape of the fiber bundles’ section showed superior mechanical performance compared to reference sections. Both characteris-tics were applied in the development of two bionic structures that were analyzed as more efficient than a literature model, and 3D printed for a visual analysis.
27
Mary, Wellington. "Ambiencia para morangueiro, em hidroponia, para a produção na entressafra e bambu como elemento construtivo para casa de vegetação". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257222.
Abstract (sommario):
Orientadores: Paulo Martins Leal, Nilton Nelio ComettiTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
Made available in DSpace on 2018-08-05T08:12:05Z (GMT). No. of bitstreams: 1 Mary_Wellington_D.pdf: 1605348 bytes, checksum: a8e234dda57614d82e240a264ada7f6c (MD5) Previous issue date: 2005
Resumo: O uso da tecnologia do cultivo protegido e hidroponia no Brasil para a produção de hortaliças e plantas ornamentais passou por diversas fases de adaptação, visando sempre a atender às necessidades de oferta e qualidade dos produtos com a preocupação de se minimizar os custos de produção e os efeitos negativos do clima. A grande maioria destas adaptações partiu da iniciativa dos próprios agricultores, utilizando-se de diferentes materiais e outros artifícios para contornar problemas do seu dia-a-dia. Com os objetivos de analisar o sistema construtivo de estrutura de bambu para utilização em casa de vegetação e testar diferentes sistemas de controle ambiental, visando à produção na entressafra do morangueiro. Foram realizados cinco experimentos na área do campo experimental da Faculdade de Engenharia Agrícola/UNICAMP, no período compreendido entre Fevereiro de 2002 e Janeiro de 2004.No primeiro experimento testou-se o uso de vigas e colunas construídas com de colmos de bambu da espécie Bambusa tuldoides Munro. As vigas e colunas foram estruturadas com espaçadores de plástico, especificamente desenhados para facilitar e padronizar a construção, conferindo-lhe maior resistência e estabilidade. Foram avaliados três espaçamentos entre colunas (2,0; 2,5 e 3,0m) sob diferentes esforços de carga, dos quais o melhor resultado foi obtido com o espaçamento de 2,5m. Nos outros experimentos o objetivo foi estudar o controle ambiental aplicado ao cultivo do morangueiro para produção na entressafra no Estado de São Paulo, cultivado em sistema NFT e aeroponia sem e com zona de resfriamento. Foram avaliados: massa fresca de cada pseudofruto/planta e massa total de pseudofrutos/planta, número de pseudofrutos e de estolhos/planta. Utilizou-se as cultivares: Campinas; Sweet Charlie; Seascape; Oso Grande e Tudla. Também foi analisado o microclima gerado pelos sistemas aeropônicos A produtividade dos sistemas aeropônicos sem e com resfriamento foi inexpressiva, porém influenciaram sobre a temperatura da solução nutritiva e do microclima dentro das bancadas. Os tratamentos envolvendo o controle de fotoperíodo e vernalização promoveram a produção durante o período de entressafra
Abstract: The use of the hydroponic technology and the Brazilian horticulture and ornamental plants had many different phases of adaptation and always looking for the necessity to offer and the quality of the production with the concern to minimise the production cost. Also to at the negative effects of the climate. The majority of these adaptations start with the farmers and they used different materials to fix their day to day problems. With the objective to analyse the constructive system of the bamboo structure for use in the vegetation house and to test different environmental control systems with the aim to look at the production between the harvest of the strawberry plants. In the period between February 2002 and January 2004 five experiments of this type were carried out at the experimental station at the College of Agricultural/Unicamp Engineering. In the first experiment they tested the use of beams and columns of colmos of Bambusa tuldoides Munro species of bamboo. The beams and columns had been structured with plastic spacers specifically made to standardize the construction, due to greater resistance and stability. Three spaces between columns (2,0, 2,5 and 3,0m) under different load efforts had been evaluated, and the best result was obtained with the spacing of 2,5m. In the other experiments the objective was to study the ambient temperature control applied to the culture of the strawberry plants for production in the period between harvests in the state of São Paulo, cultivated in NFT system and aeroponics with and without and a cooling zone. They had evaluated cool and total mass of fruit/plant, the number of fruits and stolon/plant. The varieties used had been: Campinas; Sweet Charlie; Seascape; Oso Grande and Tudla. The microclimate generated for the aeropônico system with cooling zone was also analyzed. The treatments involving the control of photoperiod had promoted the production during the period of period between harvests. Despite the aeroponics systems with and without cooling, produced during the period between harvests, the productivity was good, however they had influenced inside on the temperature of the nutritional solution and the microclimate of the different plant groups
Doutorado
Construções Rurais e Ambiencia
Doutor em Engenharia Agrícola
28
Sweeney, Benjamin Andrew. "The Effect of Biocomposite Material In A Composite Structure Under Compression Loading". DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1932.
Abstract (sommario):
While composite structures exhibit exceptional strength and weight saving possibilities for engineering applications, sometimes their overall cost and/or material performance can limit their usage when compared to conventional structural materials. Meanwhile ‘biocomposites’, composite structures consisting of natural fibers (i.e. bamboo fibers), display higher cost efficiency and unique structural benefits such as ‘sustainability’. This analysis will determine if the integration of these two different types of composites are beneficial to the overall structure. Specifically, the structure will consist of a one internal bamboo veneer biocomposite ply; and two external carbon fiber weave composite plies surrounding the bamboo biocomposite. To acquire results of this study, the hypothesized composite structure will consist of varied trapezoidal corrugated specimens and tested in uniaxial compression loading. Thereafter, this test data will be used to ultimately design, manufacture, and test a structural biocomposite/composite box, intended to carry extremely high compressive loads; relative to its own weight. A finite element analysis of this test will be used to validate experimental data. After running the experiment, the carbon fiber with bamboo test sample results were compared to that of only carbon fiber test sample. The carbon fiber samples resulted in a maximum compressive load difference of only 23% higher loads when compared to the carbon fiber with bamboo, on average. These findings are discussed throughout.
29
Andrade, Molina Vanessa Mishell. "Bambú en la construcción análisis de diferentes casos de estudio con sistemas constructivos en bambú". Master's thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/26322.
Abstract (sommario):
En la arquitectura el uso de materiales naturales ha sido implementado desde la antigüedad. Uno de los primeros materiales utilizados fue el bambú, el mismo que por sus características físicas y mecánicas ha trascendido hasta la actualidad convirtiéndose en una de las opciones más acertadas para crear arquitectura sustentable y de gran calidad. Los principales continentes que hacen uso de este material son Asia y América, en específico la zona de Latinoamérica, debido a que cuentan con las características propicias para su desarrollo y uso en la construcción. Serán destacados métodos de tratamiento, secado, unión y aplicación en obra más comunes en estos continentes, asimismo serán analizados dos casos de estudio que utilizan el bambú como elemento principal del proyecto. El primer referente es “Bamboo Sports Hall Panyaden International School” localizado en Tailandia (Asia), mientras que el referente Latinoamericano es el edificio de dormitorios de “La Ceiba” localizado en México; ABSTRACT:
In architecture the use of natural materials has been implemented since ancient times. Bamboo was one of the first materials used in construction, which, due to its physical and mechanical characteristics, has transcended until nowadays, becoming one of wisest option for creating sustainable and high quality architecture. The main continents that make use of this material are Asia and America, specifically Latin America, due to their characteristics that enhance their development and use in construction. The most common treatment, drying, structural joints, and application methods on these continents will be highlighted, as well as two case studies that use bamboo as the main element of the project. The first reference is “Bamboo Sports Hall Panyaden International School” located in Thailand, while the Latin American reference is the “La Ceiba” dormitory building located in Mexico; RESUMO:
Na arquitetura, utilizam-se materiais naturais desde a antiguedade. Um dos primeiros materiais a serem utilizados foi o bambú, que, devido às suas características físicas e mecânicas, transcendeu até à atualidade, tornando-se uma das opções mais bem-sucedidas na criação de uma arquitetura sustentável e de elevada qualidade. Os principais continentes que fazem uso deste material são a Ásia e a América, especificamente a zona da América Latina, pois possuem características propícias para o seu desenvolvimento e uso na construção. Nesta dissertação destacam-se os principais métodos de tratamento, secagem, união e aplicação do bambú nesses continentes, além de dois casos de estudo que usam o bambu como principal material de construção. O primer projeto que foi analizado foi o “Bamboo Sports Hall Panyaden International School” localizado na Tailândia, enquanto que o segundo projeto foi o edifício do dormitório “La Ceiba” localizado no México na Latino-américa.
30
Nogueira, Cláudia de Lima. "Ciência do material bambu e tecnologia de sua aplicação em vigas laminadas coladas de seção transversal composta". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-19042013-100149/.
Abstract (sommario):
No presente trabalho avaliou-se a resistência mecânica do bambu nos estágios pré e pós processamento mecânico para servir de referências básicas do estudo das propriedades mecânicas de vigas laminadas coladas simples, de seção composta e de seção composta na forma de I, industrializadas em laboratório. Iniciou-se com a caracterização do material bruto na forma de ripa que representa toda a parede do colmo, passando-se pelo material processado na forma de lâmina que representam a parte industrialmente útil da parede do colmo e culminando na manufatura e qualificação das vigas laminadas coladas. Na produção dos corpos de prova do material bruto manteve-se a espessura original da ripa, exceto para alguns produzidos para se avaliar a resistência ao cisalhamento radial das camadas interna e externa da parede do colmo. As ripas foram usinadas em diversas máquinas para serem transformadas em lâminas que são as unidades de composição das seções compostas pela técnica de aglutinação e adesão a frio. Foi estudada também a influência do nó na resistência ao cisalhamento radial e tangencial tanto do material sólido quanto do plano de cola e nas propriedades da flexão. A geometria e as dimensões dos corpos de prova de cisalhamento foram adaptadas da norma ASTM D 905 e os de flexão da norma NBR 7190. As resistências ao cisalhamento no plano de cola e as propriedade da flexão foram determinadas segundo três combinações de faces de contato no processo de colagem com o adesivo à base de resorcinolformaldeído (RF). Estudou-se também a pressão adequada para colagem dos corpos de prova e eleita a mais adequada à colagem de vigas laminadas coladas. Os corpos de prova intactos e rompidos nos ensaios foram observados em microscópio eletrônico de varredura, em microscópio óptico, em microscópio óptico de fluorescência e microscópio estereoscópico. Observou-se ampla variabilidade das propriedades mecânicas tanto do material sólido quanto do material composto, mas em qualquer dos casos de resistência houve ampla variabilidade dos dados e, no geral o material sem nó foi mais resistente do que o com nó. As rupturas ocorreram na maioria das vezes no tecido parenquimático desviando-se dos feixes de fibras e tendendo a seguir a grã do material observando que o plano de ruptura só coincide com o plano planejado para a ruptura quando o corpo de prova é feito com a consideração precisa da orientação da grã. Os corpos de prova montados com a cola à base de PVA e com lâminas nodais responderam de forma satisfatória à colagem a baixa pressão, enquanto que os fabricados com lâminas internodais apresentaram melhor desempenho a alta pressão. Para os corpos de prova manufaturados com o adesivo à base de RF, a melhor combinação de colagem se deu no contato entre faces externas de lâminas. Foi possível observar a penetração do adesivo nos elementos anatômicos das lâminas com o uso da microscopia óptica e de fluorescência. As vigas laminadas coladas de seção transversal composta foram ensaiadas à flexão, mas não romperam por tensão normal, pois apresentaram instabilidade lateral durante o carregamento à flexão. As vigas também apresentaram baixo módulo de elasticidade porque o esmagamento da mesa inferior, nos apoios, foi cofundida e somada pelo sistema de medida, ao valor da flecha. Numa análise geral, a qualidade mecânica da Viga \"I\" pode ser considerada muito boa dentro do correto cálculo do momento de inércia se seções transversais compostas. As camadas perpendiculares ao eixo da via, tanto na alma quanto na mesa, foram tão eficientes na absorção do esforço cortante que não houve nenhuma limitação de capacidade de carga pela ligação alma-mesa mesmo com a viga trabalhando numa faixa de alta influência de tensões cisalhantes.In this study it was evaluated the bamboo strength in the stages before and after mechanical processing in order to obtain basic references to study the mechanical properties of simple glued laminated beams of composite section and composed section as I joist, manufactured in laboratory scale. It started with the characterization of raw material as strip representing the crude bamboo culm wall, moved to the processed material as in the shape of laminas which were representing the majority of bamboo culm wall industrially useful and culminating to the manufacture and qualification of glued laminated beams. In the production of specimens of raw material it was maintained the original thickness for the strip except for a few ones which were produced to evaluate the radial shear strength in the inner and outer layers of the culm wall. The strips were machined on some machines to be turned into laminas that were the units for assembling composite sections by agglutination and adhesion under pressure in environmental conditions. It was also studied the node influence in the radial and tangential shear strength in both solid material and in the adhesive plan and in properties got from the bending tests. The geometry and dimensions of the shear specimens were adapted from ASTM D 905 and the bending from NBR 7190. Shear strength in the adhesive plane and bending property were determined following three combinations of contact faces on the gluing process using resorcinol-formaldehyde based adhesive. It was studied also the proper pressure for gluing the specimens and elect the most suitable for glued laminated beams. The intact specimens and failed on mechanical tests were observed under a Scanning Electron Microscope, Optical Microscope, Optical fluorescence microscope and stereomicroscope. It was observed huge variation of mechanical properties in both solid and composite materials, but in all cases there was considerable variability of strength data and in general the material without node was more resistant than with node. The ruptures mechanisms occurred most often in the parenchyma tissue by passing the fiber bundles and tend to follow the grain of the material by observing the rupture plane that only coincides with the plan designed to rupture when the specimen is done with precise consideration of grain orientation. The specimens manufactured with PVA adhesive and components with nodes responded satisfactorily to the low pressure bonding, while the specimens produced with internodes components performed better at high pressure. For specimens manufactured with resorcinol-formaldehyde adhesive the best gluing combination was given by the contact of outer laminas surfaces to each other. It was possible to observe the anchorage of the adhesive into the anatomical tissues by using optical microscopy and fluorescence optical microscopy. Glued laminated beams with composite cross section were tested in bending, but not failed by normal stresses, once there occurred only lateral instability during loading time. The I beams also showed low modulus of elasticity because the crush in the inferior flange was added by the measurement system to the bending deflection. In general the mechanical quality of the \"I\" joist can be considered very high with correct calculation of the moment of inertia of composite cross sections. The layers perpendicular to the beam axis both in web and in the flanges, were so efficient in absorbing the shear that there was no limitation of carrying load web-frange connection even with the beam working in a critical influence of high shear stresses.
31
Huang, Puxi. "Hygrothermal performance of Moso bamboo-based building material". Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715306.
Abstract (sommario):
This study focuses on the hygrothermal performance of Moso bamboo. The knowledge in this aspect is remarkable important for the research of building energy saving and the low carbon building design. However, the detailed hygrothermal properties of Moso bamboo are fairly rare. To obtain these data, a series of experimental works have been done for measurement of density, porosity, thermal conductivity, specific heat capacity, water vapour permeability, hygrothermal expansion and sorption isotherm of Moso bamboo. To obtain further understanding on the hygrothermal performance of Moso bamboo, a number of dynamic heat and moisture transfer experiments were conducted. These experiments simulated two extreme outdoor environments and one indoor environment. The temperature and RH responses of Moso bamboo panels were monitored. Then a coupled transient heat and moisture transfer numerical simulation at the material level was conducted to predict and validate the hygrothermal performance of Moso bamboo. A sensitivity study of the hygrothermal properties of bamboo was also presented to indentify the influence of each hygrothermal property of Moso bamboo. Major findings include the following aspects. Both experiment and simulation results appear to be consistent with the results of measurements of the basic hygrothermal parameters. The parametric study found that density can be regarded as the most sensible parameter to influence the temperature simulation results at the transient state, while the thermal conductivity dominated the temperature variation at the steady state. The water vapour diffusion resistance factor can be regarded as the most critical parameter to influence the RH simulation results. The influence of liquid water diffusivity is negligible in this study. The parametric study results indicated that the simulation with moisture is more accurate than the simulation without moisture in both equilibrium and transient state. The results also imply that the existence of moisture could increase the heat capacity and reduce the thermal conductivity. The results of this study recommend that the external part of the bamboo culm wall can be utilised to minimise the RH variation of the panel while the internal part of the bamboo culm wall is suitable to increase the thermal insulation performance of the panel. To avoid hygroexpansion, the implementation of external part of bamboo culm wall needs to be minimised.
32
Kassa, Bewketu Z. "Bamboo: An Alternative Building Material for Urban Ethiopia". DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/66.
Abstract (sommario):
This project explores the potential of bamboo as an alternative building material for low cost housing units suitable for urban Ethiopia. The rational for the application of bamboo comes from its abundance throughout the country, and its proven physical properties that equate it to other building material like timber, steel and concrete. The proposed bamboo based design solution concentrates on simplification of construction methods, prefabrication of structural components and vertical densification of housing units, addressing the lack of skilled labor, cost of construction time and urban land respectively. An understanding of the design solution was established by constructing a full-scale section prototype and performing laboratory tests on key structural components.
33
He, Qian. "Étude sur le mécanisme d'activation du bois/bambou/adhésif et amélioration du collage induit par le champ électrique à haute tension". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0147.
Abstract (sommario):
Dans cette étude, les équipements avancés ont été sélectionnés afin d’étudier les effets de l’HVEF sur les propriétés physicochimiques du bois et du bambou, les effets du HVEF sur la structure chimique et les propriétés rhéologiques des adhésifs sous une série de paramètres HVEF. L’effet d’agrégation de l’adhésif à l’interface de liaison induite par HVEF a également été révélé et le modèle de prédiction micro-mécanique est établi. Les principales conclusions de cette étude sont les suivantes : 1. Après le traitement HVEF, l’activité de surface du bois et du bambou a augmenté de manière significative. De plus, avec l’augmentation de la tension/temps, les radicaux libres de surface, le rapport O/C et le nombre de groupes oxygène augmentaient de manière significative tandis que l’angle de contact diminuait. 2. Avec l’augmentation de la tension / temps, des réactions intermoléculaires significativement améliorées de la résine d’urée formaldéhyde et de la résine de phénol formaldéhyde ont été obtenues. Après un traitement de 60 kV/8 minutes, un incrément significatif des pics caractéristiques des groupes Cu2012O a été obtenu. Sous le traitement de HVEF, la dépendance de température/fréquence des comportements rhéologiques des deux résines a changé de manière significative. Par conséquent, le degré de polymérisation intermoléculaire du phénol formaldéhyde et de la résine d’urée formaldéhyde peut être considérablement amélioré et la viscoélasticité de la résine peut être améliorée sous traitement HVEF. 3. Après le traitement de HVEF, la distribution de l’adhésif à l’interphase de liaison était continue et uniforme. La profondeur de pénétration a été considérablement réduite. La densité et la force de liaison à l’interphase de liaison ont été sensiblement augmentées, et le taux de délamination a été réduit. Après traitement, la densité maximale à interphase est 1081 kg/m3, qui était 32% plus haut que le contrôle. La force de collage est passée de 0,66 MPa à 1,25 MPa et le taux de bris du bois a augmenté à 85 %, et le taux de délamination a diminué à 5,97 %. Pour le matériau en bambou, la résistance de liaison a été significativement améliorée après le traitement HVEF. La force de liaison de la peau de bambou et de la peau de bambou était de 9,51MPa, et le rapport de défaillance de bambou était de 60%. Dans la combinaison de la moelle de bambou et de la moelle de bambou, le taux de défaillance maximal de bambou était de 85%, qui a été augmenté de 70%. Par conséquent, dans le cadre du traitement HVEF, la distribution continue et uniforme des adhésifs interphasés de liaison peut être obtenue, ce qui peut améliorer considérablement les performances de collage du composite de bambou de bois et est propice à l’utilisation efficace du composite de bambou de bois.4. Selon le profil de densité verticale à l’interface de liaison, le modèle de rigidité stratifiée et de distribution des contraintes de l’interface de liaison a été établi. Les résultats ont montré que l’erreur relative était inférieure à ±15 %. Sur la base du modèle de distribution, les propriétés mécaniques macroscopiques du composite sont prédites avec la combinaison de la mécanique composite et de la théorie des plaques stratifiées, y compris le module élastique, la résistance à la flexion, le module de cisaillement et la résistance au cisaillement. Les résultats ont montré que l’erreur de prédiction des propriétés mécaniques est inférieure à 30%. Avec le modèle de distribution de rigidité et de résistance, l’effet du traitement HVEF peut être caractérisé quantitativement et les propriétés mécaniques des composites traités HVEF peuvent être prédites. En conséquence, le mécanisme de renforcement de la liaison interphase peut être révélé avec le modèle de distribution de la rigidité et de la résistanceIn this study, the advanced equipments were selected in order to investigate the effects of HVEF on the physicochemical properties of wood and bamboo, the effects of HVEF on the chemical structure and rheological properties of adhesives under a series of HVEF parameters. The aggregation effect of adhesive at bonding interface induced by HVEF has also been revealed and the micro-mechanical prediction model is established.The main conclusions of this study are as follows:1.After HVEF treatment, the surface activity of wood and bamboo increased significantly. Moreover, with the increase of voltage/time, the surface free radicals, O/C ratio and the number of oxygen groups increased significantly while the contact angle decreased. Under the condition of 60kV, the surface activity highly increased. The increment of free radicals was 26%, the decrease of initial contact angle was 22%, the decrease of equilibrium contact angle was 23%, the increment of free energy component was 43% ~ 75%, the increment of O/C ratio was 34%, the increment of oxygen-containing groups were 39% (C‒OH), 149% (C‒O or C=O) and 97% (O‒C=O), respectively. Therefore, under HVEF treatment, the physical and chemical properties of wood and bamboo can be significantly improved, which is conducive to improving the interphase properties of composite materials.2.With the increase of voltage/time, significantly improved inter-molecular reactions of urea formaldehyde resin and phenol formaldehyde resin were obtained. After 60kV/8 min treatment, significant increment of the characteristic peaks of C‒O groups were obtained. Under HVEF treatment, the temperature/frequency dependence of the rheological behaviors of the two resins changed significantly. Therefore, the degree of inter-molecular polymerization of phenol formaldehyde and urea formaldehyde resin can be significantly improved and the viscoelasticity of the resin can be improved under HVEF treatment.3.After HVEF treatment, the distribution of adhesive at the bonding interphase was continuous and uniform. The penetration depth was significantly reduced. The density and bonding strength at the bonding interphase were significantly increased, and the delamination rate was reduced. After treatment, the maximal density at interphase is 1081 kg/m3, which was 32% higher than the control. The bonding strength increased from 0.66MPa to 1.25MPa and the wood breaking rate increased to 85%, and the delamination rate decreased to 5.97%. For bamboo material, the bonding strength was significantly improved after HVEF treatment. The bonding strength of bamboo skin and bamboo skin was 9.51MPa, and the bamboo failure ratio was 60%. In the combination of bamboo pith and bamboo pith, the maximum bamboo failure ratio was 85%, which was increased by 70%. Therefore, under HVEF treatment, the continuous and uniform distribution of bonding interphase adhesives can be obtained, which can significantly improve the bonding performance of wood bamboo composite, and is conducive to the efficient utilization of wood bamboo composite.4. According to the vertical density profile at the bonding interface, the laminated stiffness and stress distribution model of the bonding interface has been established. The results showed that the relative error was less than ±15%. Based on the distribution model, the macroscopic mechanical properties of composite are predicted with the combination of composite mechanics and laminated plate theory, including elastic modulus, bending strength, shear modulus and shear strength. The results showed that the prediction error of mechanical properties is less than 30%. With the stiffness and strength distribution model, the effect of HVEF treatment can be quantitatively characterized and the mechanical properties of HVEF treated composites can be predicted. As a result, strengthening mechanism of bonding interphase can be revealed with the the stiffness and strength distribution model
34
Ferreira, Gisleiva Cristina dos Santos 1975. "Vigas de concreto armadas com taliscas de bambu Dendrocalamus Giganteus". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258260.
Abstract (sommario):
Orientador: Armando Lopes Moreno JuniorTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: A utilização do bambu como elemento estrutural vem sendo estudada há dezenas de anos, apresentando excelentes resultados em relação às suas características físicas e mecânicas. Assim, alguns pesquisadores iniciaram nas últimas décadas estudos para viabilizar a aplicação do bambu como armadura em elementos de concreto. Neste sentido, este trabalho pretende apresentar soluções ao principal problema de utilização do bambu como armadura em elementos estruturais de concreto, um modelo de dimensionamento eficaz, determinado os Estados limites últimos e de utilização. Para tanto, escolheu-se a espécie de bambu Dendrocalamus giganteus (Gigante) devido suas dimensões e fácil obtenção em todo território do Brasil. Os colmos de bambu foram divididos em taliscas com seção transversal de 2 x 1 cm (largura x espessura). Em seguida, realizaram-se ensaios de caracterização física e mecânica, de acordo com procedimentos existentes na literatura e propostos neste trabalho. A partir dos resultados destes ensaios e dados propostos por FERREIRA (2002), foi realizado o dimensionamento teórico seguindo os procedimentos da NBR 6118 (2003). Para tanto, foi considerado o Estádio II, considerando-se como Estado limite último a deformação última do bambu igual a 2,0 ¿ e o encurtamento último do concreto igual a 3,5 ¿. Já para o Estado limite de utilização, foi determinada a força cortante máxima e o deslocamento vertical máximo. Foram confeccionadas 6 vigas com armadura longitudinal de taliscas de bambu retas e dobradas sem tratamento para melhorar a aderência. Os resultados indicaram possibilidades na utilização de taliscas de bambu como armadura em vigas de concreto, havendo a necessidade dos cálculos serem realizados conforme o Estádio II. A utilização da armadura de bambu dobrada proporcionou uma melhor distribuição das fissuras e conseqüentemente, uma melhor ancoragem da armadura
Abstract: The use of bamboo as a structural element has been studied for some years, presenting excellent results relating to its physical and mechanical characteristics. Therefore, some researches began in last decade¿s studies to apply bamboo as reinforcement in concrete elements. In this sense, this work has intended to present solutions to most common problem in the application of bamboo in structural concrete elements: an efficient calculus procedure, obtaining the limit states. Thus, it was chosen de Dendrocalamus giganteus specie because it¿s easy to find this specimen in Brazil and because of its dimensions. The bamboo caulis were cut in strips with 2 x1 cm cross section. Then it was realized physical and mechanical characterization tests, in accordance to literature proceedings ant methods proposed in this work. From this tests results and according to FERREIRA (2002), it was conducted the theorical calculus respecting NBR 6118 (2003). It was considered second state, determining as an ultimate limit state the ultimate deformation of the bamboo equal to 2,0¿. For the service limit state it was determined the maximum vertical displacement. It was constructed six beams with longitudinal reinforcement of bamboo strips without adherence treatment and without stirrups. Three of this beams had its strips bent. The results indicate the possibilities in the use of bamboo strips as reinforcement of concrete beams, following second state. The use of bent strips provided a better distribution of the cracks and consequently a better anchorage of the reinforcement
Doutorado
Arquitetura e Construção
Doutor em Engenharia Civil
35
RAMBO, CARLOS R. "Sintese e caracterizacao de ceramicas biomorficas". reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10973.
Abstract (sommario):
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
36
Holmström, Emelie. "Bambusa vulgaris as a roof material : A field study about bamboo age, treatment and the possibility to build with bamboo in Ghana". Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-128814.
Abstract (sommario):
The purpose of this report was to investigate bamboo (Bambusa vulgaris) and to gain a wider knowledge about bamboo as a construction material. A growing problem all over the world is global warming caused by carbon dioxide emissions. Bamboo is a giant grass and can absorb more carbon dioxide in comparison to same-sized trees. The majority of bamboo species growing in Ghana is Bambusa vulgaris. The results are based on six qualitative semi-structured interviews conducted in Ghana and five supplementary interviews by e-mail conversations. The investigation was carried out in Greater Accra region, Ashanti region, and Western region in Ghana. The results of this survey showed that Bambusa vulgaris has the best properties for construction at four years of age and needs treatment to last longer than two years. The interviews also revealed that there is currently no example of a built corrugated bamboo roof in the country, instead traditional bamboo roofs are common in the rural areas. Natural material needs to increase in the urban areas for environmental purposes because cement and metal are standard material in the Greater Accra region. Therefore, roofing with bamboo can be a good idea. If bamboo becomes the main building material, it is possible that bamboo plantation will expand in Ghana and that contributing to overall reduced the CO2 emissions. The conclusion is to build with four year old bamboos and use bamboo instead of wood or traditional bamboo roofs as alternatives to corrugated bamboo roofing sheets in the country.
37
Silva, Rodolfo Gomes da. "Tratamento de bambu com ácido pirolenhoso contra a deterioração por brocas". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256862.
Abstract (sommario):
Orientador: Antonio Ludovico BeraldoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
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Resumo: A concentração da população mundial em grandes centros urbanos gera uma imensa demanda por madeira, o que tem levado à devastação das florestas tropicais, causando a extinção de várias espécies. O bambu é uma alternativa à madeira convencionalmente utilizada na movelaria, na construção, na produção de energia, na fabricação de papel e celulose e em outras atividades industriais. Apesar das numerosas vantagens econômicas e ambientais do bambu, seu uso esbarra na limitada durabilidade natural da maioria das espécies. A deterioração do bambu, causada por agentes físicos, químicos e biológicos, faz com que esse vegetal seja considerado um material de baixa qualidade, criando a falsa ideia de que o bambu somente deveria ser usado quando da falta de materiais mais apropriados para determinados fins. Os principais agentes deterioradores do bambu são os fungos e os insetos, dentre os quais se destaca a broca do bambu. A proteção do bambu pode ser feita por meio do uso de diversos produtos dentre os quais se destaca o ácido pirolenhoso, obtido a partir da pirólise de madeira e de outros materiais vegetais. No presente trabalho, buscou-se avaliar a eficácia do tratamento aplicado a taliscas de bambu por cozimento em ácido pirolenhoso em três diferentes diluições (10, 20 e 30%) durante cinco intervalos de tempo (15, 30, 60, 120 e 180 minutos), buscandose a sua proteção contra a deterioração pela broca do bambu, avaliando-se o dano nas taliscas de bambu através das variações na massa e na velocidade do pulso ultrassônico (VPU) através dessas taliscas. Os experimentos de deterioração foram realizados durante 20 semanas. Os dados foram sujeitos a testes de correlação e interações entre as variáveis. O teste T pareado indicou haver diferença significativa entre as medidas de VPU e massa no início e depois de 20 semanas de ensaio. Em média, a VPU diminuiu e a massa aumentou, resultado este influenciado pela variação de umidade no período. Buscou-se, ainda, determinar a porcentagem de fibras em relação aos outros tecidos por meio de análise de imagens de cortes transversais dos corpos de prova. Por fim, buscou-se estabelecer um método eficiente de criação de Dinoderus minutus para ensaios de deterioração do bambu
Abstract: The concentration of worldwide population in large urban centers creates huge demand for timber, which can lead to devastation of the rainforest, resulting in the extinction of several species. Bamboo is an alternative to wood commonly used on furniture, building, power generation, pulp and paper and other industrial purposes. Despite its many economic and environmental advantages, the bamboo utilization is hampered by the low natural durability of most species. The bamboo deterioration by physical, chemical and biological agents, makes it to be considered a low quality material, creating the misconception that it should only be used in the abscence of appropriate materials for certain purposes. The major spoilage agents on the bamboo are the fungi and insects, among which stands out the powder-post beetle. The bamboo protection can be done through the use of various protective agents such as the pyroligneous acid, obtained by pyrolysis of wood and other plant materials. This study aimed to evaluate the efficacy of the treatment applied to bamboo splits cooked in pyroligneous acid at three different solutions (10, 20 and 30%) over five time intervals (15, 30, 60, 120 and 180 minutes) searching for the protection against the deterioration of the powder-post beetle by measuring the variation of the mass and the ultrasonic pulse velocity (UPV) across the strips. The deterioration assays were performed during 20 weeks. The data were subjected to correlation and interaction between variables tests. The two-sample pooled t-test indicated significant differences between the measures of UPV and mass at starting and after 20 weeks testing. On average, the UPV decreased and increased mass, a result influenced by the increasing relative moisture. The study also aimed to determine the fiber content by image analysis of transverse sections of the bamboo splits. Finally, the study sought to establish an efficient method of creating Dinoderus minutus for bamboo deterioration tests
Mestrado
Construções Rurais e Ambiencia
Mestre em Engenharia Agrícola
38
Nunes, Antônio Ricardo Sampaio. "Construindo com a natureza bambu : uma alternativa de ecodesenvolvimento". Universidade Federal de Sergipe, 2005. https://ri.ufs.br/handle/riufs/4337.
Abstract (sommario):
This work aims at investigating the application of the bamboo as a construction material in the State of Sergipe, Brazil, through the analysis of the aspects deriving from its use
process, them being: economical efficiency, the material´s physical and mechanical properties, local workforce output, acceptance level by the local population, a esthetical
results of the bamboo in architectural applications and its possibilities of ecological development. The method employed in this scientific investigation was action-research,
which made use of a coordinated collective action plan of technical, social and cultural character, oriented towards the solving of conceptual, technical and operational problems
which arose from research matters raised throughout this project. The action selected so as to proceed in an investigation which could lead to solving such questions was the
construction of a house in which the bamboo was a priority as a material employed. The designated sight for the construction was the ´´Horto do Diogo´´, located on the Oiterinhos
farm, a Petrobras property, in the city of Carmópolis, state of Sergipe, Brazil. Under the perspective of ecological development, it is the project´s objective to investigate the use of the bamboo as an alternative in environmentally sustainable development contextualized in a technological, social, economic and cultural process. The ecological development is a strategy used in order to overcome the barriers imposed by a dominating market economy.
For it to be fully successful, the development of proper technologies which can make the most of both bio and human diversity of each ecosystem particularly (whether local or
regional) is essential. The bamboo has proven to be a plant and a material of enormous potentialities, presenting physical and mechanical properties (proved herewith) which qualify it as a widely accessible and easily usable material by either rural or peripheral urban populations of small cities, thereby being regarded as an alternative in sustainable community development as well as ecological development.Este trabalho teve como objetivo investigar as possibilidades de aplicação do bambu como um material de construção em Sergipe, analisando-se os aspectos decorrentes do processo de uso, quais sejam: eficiência econômica, propriedades físicas e mecânicas do material, desempenho da mão de obra local, níveis de aceitação do material pela população usuária, desempenho estético do bambu na arquitetura e suas possibilidades de ecodesenvolvimento. O método empregado para esta investigação foi o da pesquisa-ação que utilizou uma ação coletiva planejada de caráter técnico, social e cultural, orientada em função da resolução de problemas conceituais e técnicos operacionais, levantados nas questões de pesquisa. A ação escolhida para se proceder a investigação que levaria a responder tais questões foi a construção de uma edificação cujo material aplicado seria prioritariamente o bambu. O local escolhido para construção foi o Horto do Diogo, situado na fazenda Oiteirinhos de propriedade da Petrobrás, no município de Carmópolis, estado de Sergipe, Brasil. Foi sob a perspectiva do ecodesenvolvimento que propomos investigar o uso do bambu como uma alternativa para o desenvolvimento com sustentabilidade ambiental contextualizando-o num processo tecnológico, social, econômico e cultural. O ecodesenvolvimento é o fundamento para o entendimento da ecotécnica como uma estratégia para superar as barreiras impostas pela economia de mercado dominante. Para o seu sucesso toma-se fundamental o desenvolvimento de tecnologias apropriadas que absorvam o melhor da diversidade tanto humana como natural de cada ecossistema (local ou regional) de forma particular. O bambu se revela como uma planta e um material de grandes potencialidades, sendo comprovadas nesta pesquisa, as suas propriedades físicas e mecânicas que o qualifica como um material de fácil uso por populações rurais ou periféricas de pequenas cidades, se afirmando como uma alternativa de desenvolvimento comunitário sustentável e ecodesenvolvimento.
39
Ramirez-Quintero, Deyber Alexander 1985. "Influência da granulometria do material inerte e da composição de misturas binárias contendo areia e partículas de bambu (in natura e carvão produto do processo pirolítico) sobre a fluidodinâmica de leitos fluidizados". [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265823.
Abstract (sommario):
Orientador: Araí Augusta Bernárdez PécoraDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: A aplicação de biomassas em processos de geração de energia como a combustão, pirólise e gaseificação, operando com a tecnologia de leito fluidizado, tem merecido atenção crescente nas últimas décadas. Esses sistemas necessitam da adição de partículas de material inerte que ajudam a promover uma fluidização estável, permitindo a melhoria da eficiência de tais processos. Dentre as biomassas com potencial para geração de energia sustentável está o bambu, material que apresenta propriedades semelhantes às de outras biomassas utilizadas em processos de geração de energia, com a vantagem de apresentar rápido crescimento, fácil propagação, regeneração vigorosa, maturidade rápida. O objetivo deste projeto foi estudar o comportamento fluidodinâmico de misturas de partículas de areia e bambu (in natura e na forma de carvão proveniente de processo de pirólise) visando à obtenção de parâmetros inerentes à fluidização dessas misturas, bem como analisar o efeito da degradação térmica da partícula de bambu sobre a fluidização do leito. A análise foi realizada a partir do levantamento experimental da curva fluidodinâmica em sistema de leito fluidizado operando a frio, com diferentes composições das misturas bambu-areia e carvão-areia. Adicionalmente foi verificada a influência do tamanho das partículas de areia e da altura estática do leito sobre a fluidodinâmica do leito. Os resultados mostraram que a melhor qualidade da fluidização do leito contendo partículas de bambu in natura foi obtida usando a areia identificada como areia 3 (diâmetro médio de 460 µm), relação entre a altura estática do leito e o diâmetro do leito igual à unidade (H/D = 1) e máximo teor de biomassa no leito igual a 5% (em massa). No entanto, esse tamanho areia não forneceu boas condições de fluidização para a mistura carvão-areia. A utilização da Umf do material inerte para o projeto de reatores de pirólise, utilizando partículas de bambu como combustível, não é recomendável, uma vez que a presença de apenas 5 % (em massa) de bambu in natura aumenta o valor da Umf em 20 %, enquanto que esse aumento é de 10 % no leito contendo carvão de bambu. Espera-se que os resultados obtidos neste estudo forneçam dados úteis para o projeto de reatores que utilizam a tecnologia de leito fluidizado. Pretende-se também contribuir para o entendimento da fluidodinâmica de sistemas que utilizam misturas de biomassas e areia para geração de energia
Abstract: The use of biomass in power generation processes such as combustion, pyrolysis and gasification, operating with the fluidized bed technology, has received increasing attention in recent decades. These systems require the addition of inert particles to promote a stable fluidization, allowing the improvement of process efficiency. Among the biomasses with potential for sustainable power generation is bamboo, which presents similar properties to other biomasses used in energy generation processes, with the advantage of rapid growth, easy propagation, vigorous regeneration and quick maturity. In addition, its properties allow the recovery of environmentally degraded areas. The objective of this research was to study the hydrodynamics behavior of fluidized beds composed by mixtures of sand and bamboo particles (in natura and in the form of coal from pyrolysis process). Parameters inherent to fluidization of these mixtures, as well as the effect of thermal degradation on the fluidization process of bamboo particles are analysed. The analysis was performed from hydrodynamics curves obtained in an experimental system operating at room temperature, with different compositions of bamboo in nature and bio-char in the bed. Additionally, the influences of sand particle size and static bed height on the fluidized bed hydrodynamics were verified. Results showed that the best quality of fluidization of the studied mixtures was achieved using sand particles 460 ?m diameter (sand 3), static bed height and column diameter ratio equal to unity (H/D = 1) and maximum weight fraction of bamboo in the bed equal to 5%. However, this size of sand particles did not provide a good quality of fluidization for coal-sand mixture. The Umf of the inert material is not recommended to be used in the design of pyrolysis reactors as the addition of 5 wt% of bamboo in natura in the bed causes an increment of 20 % on Umf while this increment is 10 % for the bed containing bamboo char. Results obtained from this study could provide useful data for the design of fluidized bed reactors that operate with bamboo particles. It is also intended to contribute on understanding the hydrodynamics behavior of fluidized beds using mixtures of biomass and sand for power generation
Mestrado
Termica e Fluidos
Mestre em Engenharia Mecânica
40
Oliver, Borrachero Bernardo Antonio. "Estudio de la utilización de fibras naturales en materiales compuestos laminados para fabricación de componentes de automoción". Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/165809.
Abstract (sommario):
[ES] La evolución de la tendencia del pensamiento de la gente en los últimos años ha cambiado, llevándonos a adquirir nuevos valores enfocados en la sostenibilidad de los recursos naturales y el respeto hacia el medio ambiente. Con ello, la perspectiva de producto se ha visto afectada en todos los sectores, incluido el sector de la automoción. La aparición de nuevas normas medioambientales han establecido obligaciones sobre los fabricantes de vehículos respecto a la reducción de consumo y emisiones contaminantes por lo que cada vez es más habitual identificar materiales ligeros en vehículos de uso cotidiano con la finalidad de mejorar la eficiencia energética a partir de la reducción de masa.
El presente estudio pretende avanzar un paso más en la utilización de materiales compuestos centrando su temática en el desarrollo de nuevos materiales para la fabricación de componentes estructurales de vehículos que permitan la reducción de consumos desde un punto de vista sostenible. Para ello se plantea la aplicación de nuevos materiales compuestos basados en la utilización de fibras naturales, que sustituyan a los materiales utilizados tradicionalmente. En el estudio se plantea la utilización de una única matriz (epoxi) común a todos los tejidos naturales ensayados que permita realizar un estudio comparativo centrado en los tejidos, para obtener un material compuesto eficiente en su fabricación, uso y reciclaje buscando el equilibrio entre densidad, coste, resistencia y reciclabilidad.
El estudio ha consistido en la realización de ensayos de tracción, compresión, flexión, impacto, dureza, cortadura y fatiga, a partir de los cuales se han podido extraer las propiedades mecánicas necesarias para realizar un modelo MEF uniaxial en el software ANSYS ACP, comparando resultados con distintas orientaciones de fibras. Tras esto, se ha dimensionado un componente utilizando el modelo MEF uniaxial para un estudio multiaxial. Este componente ha sido fabricado y posteriormente ensayado en un banco de fatiga con la finalidad de contrastar los resultados del software con los obtenidos empíricamente, y a su vez validar la aplicación.[CA] L'evolució de la tendència del pensament de la gent als últims anys ha canviat, portant-nos a adquirir nous valors enfocats a la sostenibilitat dels recursos naturals i al respecte cap al medi ambient. A causa d'això, la perspectiva de producte s'ha vist afectada en tots els sectors, inclòs al sector de l'automoció. L'aparició de noves normes mediambientals han establit obligacions sobre els fabricants de vehicles respecte a la reducció de consum i emissions contaminants pel que cada vegada és més habitual identificar materials lleugers en vehicles d'ús quotidià amb la finalitat de millorar l'eficiència energètica a partir de la reducció de massa. El present estudi pretén avançar un pas més en la utilització de materials compostos centrant la seua temàtica en el desenvolupament de nous materials per a la fabricació de components de vehicles que permeten la reducció de consums des d'un punt de vista sostenible. Per a això es planteja l'aplicabilitat de nous materials compostos basats en la utilització de fibres naturals, que substituïsquen els materials emprats tradicionalment. En l'estudi es planteja la utilització d'una única matriu (epoxi) comú a tots els teixits naturals assajats que permeta realitzar un estudi comparatiu centrat en els teixits per obtindre un material compost eficient en la seua fabricació, ús i reciclatge, buscant l'equilibri entre densitat, cost, resistència i reciclabilitat. L'estudi ha consistit en la realització d'assajos de tracció, compressió, flexió, impacte, duresa, tallant i fatiga, a partir dels quals s'han pogut extraure les propietats mecàniques necessàries per a realitzar un model MEF uniaxial al programa ANSYS ACP, comparant resultats amb diferents orientacions de fibres. Després d'això, s'ha dimensionat un component utilitzant el model MEF uniaxial per a un estudi multiaxial. Aquest component s'ha fabricat i posteriorment s'ha assajat en un banc de fatiga amb la finalitat de contrastar els resultats del programa amb els obtinguts empíricament, i alhora ha servit per validar l'aplicació.
[EN] The evolution of the trend of people's thinking in recent years has changed, leading us to acquire new values focused on the sustainability of natural resources and respect for the environment. As a result, the product outlook has been affected in all sectors, including the automotive. The imposition of new environmental regulations has established obligations for vehicle manufacturers in terms of fuel consumption and polluting emissions, which is why it is increasingly common to identify lightweight materials in everyday vehicles, in order to improve energy efficiency through from mass reduction. This study seeks to advance the use of composite materials, focusing its theme on the development of new materials for the manufacture of structural vehicle components. For this, it is proposed the development of new composite materials based on the use of natural fibers is proposed to replace the materials traditionally used. In the work is proposed a comparative study focused on fabrics, using a single matrix (epoxy) common to all the test specimens, to obtain an efficient composite material in its manufacture, use and recycling, seeking the balance between density, cost, resistance and recyclability. During the development of the research, it has been necessary to perform tensile, compression, bending, impact, hardness, shear and fatigue tests to extract the mechanical properties necessary to make a uniaxial MEF model in the ANSYS ACP software, comparing results with different orientations fibers. After this, a component has been dimensioned using the uniaxial FEM model for a multiaxial study. This component has been manufactured and subsequently tested in a fatigue bench in order to compare the results of the software with those obtained empirically, and in turn validate the application.
Oliver Borrachero, BA. (2021). Estudio de la utilización de fibras naturales en materiales compuestos laminados para fabricación de componentes de automoción [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/165809
TESIS
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Sánchez, Vivas Lorena. "Bamboo as a Sustainable Engineering Material: Mechanical Properties, Safety Factors, and Experimental Testing". Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7925.
Abstract (sommario):
With exponential global population growth occurring and associated environmentally destructive consumption of natural resources, alternative materials that are fast growing and sustainable are being sought out to satisfy human needs. One material that is fast growing and sustainable that can be used to meet most basic needs of humans (i.e. shelter, food, tools) is the plant bamboo, of the grass family Poaceae. Bamboo was used in the past by native peoples who lived in the environment where bamboo natively grows (all continents except Europe and Antarctica) with proven success for uses such as shelter, piping, tools, wells, food, fencing, baskets and much more. These practices were mostly abandoned and deemed obsolete due to the introduction of long lasting ‘modern’ building materials of steel and concrete which gained popularity in the 1800s. Now, in the current century with much advancement in science, technology, and education, humanity is reconsidering many practices and returning to more ancient practices and ways that are better for human health, the environment, and overall sustainability.
These environmental considerations are drivers of this research, which focuses on how to use bamboo for engineering applications. First, in order to use a material for engineering and design applications, a material must be destructively tested to attain material property values. Therefore, a critical examination of the bamboo mechanical property values published literature was performed. It was found that although many scientists all over the world have been working on mechanical property testing of bamboo, their results have been published in different journals, in different languages, and had not yet been aggregated and compared. This led to the first study in this work that analyzed mechanical property data from 43 bamboo peer-reviewed publications written in English, Spanish, and Portuguese (the three main languages in which bamboo literature is published). This study focused on aggregating mechanical property values, establishing a range of values for each property as well as an average, and correlating the difference in property values to bamboo variables stated in bamboo literature (age, bamboo species, density, moisture content, post-harvest treatment, and testing standard employed). The five mechanical properties reviewed were: shear strength, compressive strength, tensile strength, bending strength / modulus of rupture (MOR), and modulus of elasticity (MOE) and their average values were 9 MPa, 52 MPa, 159 MPa, 120 MPa, and 16 GPa, respectively. Although a thorough graphical set of analyses were performed attempting to correlate the difference in mechanical property values to the previously listed variables, and only main variables found to influence strength values were moisture content and specific testing standard employed.
The results of the high range of mechanical property values with no variable with which to separate the results to lower the range, led to the second part of the research. It incorporated the high range of values reported in the literature but was able to establish safety factors and reduction factors alongside corresponding failure rates. This work allows for a designer to use bamboo culms choosing a failure rate he/she deems appropriate for structural bamboo construction. The analyses in this work were performed using Allowable Stress Design (ASD) and Load and Resistance Factor Design (LRFD) equations applied to bamboo as well as Monte Carlo statistical analyses for verification. The raw data and statistically analyzed data of 25 publications were used for this analysis, yielding 3806 strength test values (shear strength, compressive strength, bending strength / modulus of rupture, and tensile strength). Shear strength safety factors ranged from 1.38-3.58 for failure ratios from 1:6-1:25000; compressive strength from 1.30-2.79; bending strength from 1.43-4.03; tensile strength from 1.66-7.43. No singular safety factor is suggested for design as that is due to the judgment of the designer of what failure ratio he/she deems appropriate for the specific application.
Although many compression tests have been performed on bamboo, there are no known tests which destructively test bamboo after an extended period of time after harvesting (more than ~3 months). This experiment conducted a field experiment to test the functionality of using bamboo for the application of installing bamboo wells to provide groundwater. The bamboo tested in the third part of the study was of two species, Dendrocalamus giganteus and Dendrocalamus asper half of which were 1) air-dried in a laboratory for 3.5 years and the other half of which was 2) inserted in the ground as bamboo wells. The bamboo culms (or poles) had been separately treated in three different ways right after cutting: 1/3 with a borax and boric acid solution (most conventional treatment in the industry), 1/3 with coconut oil (experimental treatment in the literature), and 1/3 air-dried, a non-treated control. Bamboo wells are said to be used in ancient times as well as in more recent applications in the 1990s in India by small scale farmers. The publication of bamboo well studies have been very few and nearly no scientific analyses had been performed on them. Therefore, six bamboo wells were assembled and installed at the University of South Florida Geopark, the first of their kind in the U.S. These wells were half of species D. giganteus and half of species D. asper and also treated individually using the three different treatments described above. The wells were monitored for pH and presence of leached boron for a 3.5-year monitoring period and then removed. Upon removal, the bamboo well casings were examined for molds present as well as by mechanical compression testing to assess degradation in comparison to each other (of different treatments) and to air-dried control samples maintained in the laboratory for 3.5 years. The mold fc. Acrodictys was observed to cover the entire inner portion of the bamboo (inner diameter), from the surface level up to the water table. The lab air-dried control samples had compression strength and compressive modulus of elasticity values correlating to those found in the literature, 44-90 MPa (72 MPa average) and 15-31 GPa, respectively. Removed well samples exhibited compressive strengths and compressive modulus of elasticity values of 22-61 MPa (39 MPa average) and 7-25 GPa, respectively. This study revealed that bamboo wells were feasible and although their compressive strengths lowered by around a half after being in the ground for 3.5 years, their compressive strength and compressive modulus of elasticity values were still in the range of bamboo tested in the literature.
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Moraes, Maria Júlia Bassan de. "Estudo do potencial da cinza de folha de bambu para sua utilização como material pozolânico e sustentável em matrizes cimentantes /". Ilha Solteira, 2019. http://hdl.handle.net/11449/180946.
Abstract (sommario):
Orientador: Jorge Luís AkasakiResumo: O contexto mundial de preocupação em relação ao meio-ambiente, seu uso desenfreado e a emissão dos gases estufa, principalmente a emissão de dióxido de carbono destacou a importância da pesquisa para se buscar novas alternativas sustentáveis nos meios de produção, dentre eles se encaixa a indústria do cimento Portland. A proposta deste estudo é uma nova alternativa sustentável para a construção civil, estudando a cinza de folha de bambu (CFB) como material pozolânico para ser utilizado como substituição parcial do cimento Portland. A cinza de folha de bambu foi produzida através de um processo de autocombustão sem temperatura controlada, e foi caracterizada física e quimicamente através dos ensaios de Fluorescência de Raio – X (FRX), determinação do teor de sílica amorfa, Difratometria de Raio – X (DRX), Granulometria a Laser, Microscopia Eletrônica de Varredura por Emissão de Campo (FESEM), Espectroscopia de Infravermelho por Transformada de Fourier (FTIR) e Analise Termogravimétrica (TGA). Sua reatividade foi analisada através dos ensaios de condutividade elétrica e pH, ensaio de Frattini e pastas de Cal/CFB e Cimento/CFB, as quais foram submetidas aos ensaios de FTIR, TGA e FESEM. Para avaliar sua influência na argamassa no estado fresco e endurecido, foram realizados os ensaios de índice de consistência e o ensaio de resistência à compressão, comparando-se as argamassas com substituição parcial do cimento à uma argamassa controle, sem adição mineral. Já a influência da ci... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The global context of concern for the environment, its unrestrained use and emission of greenhouse gases, especially the emission of carbon dioxide, highlighted the importance of research to find new sustainable alternatives in the means of production, among them, the Portland cement industry. The proposal of this study is a new sustainable alternative for civil construction, studying bamboo leaf ash (BLA) as pozzolanic material to be used as partial replacement of Portland cement. The bamboo leaf ash was produced by a process of autocombustion without temperature control, and was characterized physically and chemically by means of X - Ray Fluorescence (FRX), determination of the amorphous silica content, X - Ray Diffractometry (XRD), Laser Granulometry, Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). The reactivity analysis was carried out by means of electrical conductivity and pH measurements, Frattini analysis and calcium hydroxide / CFB and Cement / CFB pastes, which were assessed by FTIR, TGA and FESEM analysis. In order to evaluate its influence on the mortar in the fresh and hardened states, the tests of consistency index and compressive strength were carried out, comparing mortars with cement partial replacement with a control mortar, without mineral addition. The influence of the ash on durability was analyzed by means of mercury intrusion porosimetry analysis (MIP) and acid ne... (Complete abstract click electronic access below)
Mestre
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Juárez, González Diego Alonso. "Uso y rentabilidad del bambú como material estructural de construcción". Bachelor's thesis, Pontificia Universidad Católica del Perú, 2019. http://hdl.handle.net/20.500.12404/15946.
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Тининика, Анастасія. "Сучасні тренди предметного дизайну (бамбук: звернення до ремесла)". Thesis, Київський національний університет технологій та дизайну, 2018. https://er.knutd.edu.ua/handle/123456789/10847.
Abstract (sommario):
Розглянуто основні характерні особливості виробів з бамбуку в контексті культурного синтезу традицій та інновацій в галузі предметного дизайну. На прикладах аналізується застосування бамбуку як екоматеріалу при створенні виробів предметного дизайну.The main characteristics of bamboo products are considered in the context of the cultural synthesis of traditions and innovations in subject design. The examples analyze the use of bamboo as an eco-material when creating articles of subject design.
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Tranquilin, Ricardo Luis [UNESP]. "Estudo das propriedades microestruturais e ópticas do BaMoO4 processado em hidrotermal assistido por microondas". Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/88504.
Abstract (sommario):
Made available in DSpace on 2014-06-11T19:23:30Z (GMT). No. of bitstreams: 0
Previous issue date: 2009-09-18Bitstream added on 2014-06-13T19:50:19Z : No. of bitstreams: 1
tranquilin_rl_me_bauru.pdf: 1401003 bytes, checksum: 671b0d9181df24fb0ba937b77bcac1d8 (MD5)O estudo das propriedades fotoluminescentes nos diferentes materiais tanto orgânicos e inorgânicos tem despertado muito o interesse da comunidade científica. Dentre os molibdatos, destacamos o molibdato de bário (BAMoO4) devido suas propriedades ópticas e termoelétricas que junto com suas emissões luminescentes no azul, verde e laranja o tornam um importante material. Neste trabalho, pós de molibdato de bário foram sintetizados pelo método de coprecipitação e processados a 140 ºC por diferentes tempos, em hidrotermal assistido por irradiação de microondas. A caracterização dos pós foi realizada através de difração de raios - X, espectroscopia Raman, absorção na região do infravermelho. As análises microestruturais e morfológicas destes pós foram realizadas através das técnicas de microscopia eletrônica de varredura por canhão de elétrons e microscopia de Transmissão. As propriedades ópticas foram verificadas por meio da espectroscopia na região do ultravioleta visível e medidas de fotoluminescência.
The study of properties in different photoluminescent both organic and inorganic materials has attracted much interest form the scientific community. Among the molybdate,. the highlight of barium molybdate (BaMoO4) because their optical properties and thermoelectric that along with its luminescent emission in blue, green and orange make it an important material. In this work of barium molybdate were synthesized by co-precipitation method and processed at 140 ºC for diferent times in hydrothermal assisted by microwave irradiation. The characterization of powders was carried out by-ray diffraction - X, Raman spectroscopy, absorption in the infrared region. The micro structural and morphological analyses of these powders were performed using the techniques of field emission gun scanning electronic microscopy and by trasmission electronic microscopy. The optical properties were observed by spectroscopy in region the ultraviolet visible and measures of photoluminescence.
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Correia, Viviane da Costa. "Produção de celulose nanofibrilada a partir de polpa organossolve de bambu para nanoreforço de compósitos cimentícios". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/74/74133/tde-04092015-104346/.
Abstract (sommario):
Fibras vegetais de baixo módulo de elasticidade são conhecidas pela sua capacidade de aumentar a energia absorvida durante o carregamento dos materiais cimentícios, especialmente no estágio pós-fissurado. A utilização de nanofibras celulósicas pode contribuir para a tenacificação de matrizes frágeis, tanto por melhorar o empacotamento das partículas, com o refinamento de poros, quanto pela interceptação de fissuras na escala nanométrica, com a respectiva absorção de energia. A celulose nanofibrilada provém de um recurso natural, abundante e renovável, possui bom desempenho mecânico e superfície específica elevada, o que contribui para melhorar a adesão entre as partículas de cimento. Estes fatores justificam o uso da celulose nanofibrilada e a tornam uma boa alternativa como nanoreforço de materiais cimentícios. Com isso, o objetivo deste trabalho foi a produção de celulose nanofibrilada a partir de polpa organossolve de bambu, definindo a melhor condição para sua produção e posterior utilização como reforço em compósitos híbridos (reforçados na nano e micro escalas) em comparação a compósitos reforçados somente com microfibras (polpa) pelos processos de produção por sucção e prensagem, e extrusão. A celulose nanofibrilada foi produzida utilizando-se polpa não-branqueada e branqueada, por meio de 5, 10, 15 e 20 ciclos de nanofibrilação pelo processo grinding. Foram realizados testes químicos, físicos e mecânicos para definição da condição ótima de nanofibrilação. A celulose nanofibrilada não-branqueada produzida mediante 10 ciclos foi definida como a melhor opção para utilização nos compósitos híbridos, por possuírem maior módulo de elasticidade e, em razão da sua maior estabilidade estrutural, apresentam maior resistência à degradação em meio alcalino. Os compósitos foram submetidos à cura por carbonatação acelerada para mitigação da degradação da fibra pela diminuição do pH da matriz e também para refinamento dos poros. Os compósitos foram submetidos ao teste de envelhecimento acelerado por meio de 200 ciclos de imersão e secagem para análise da sua degradação. Os compósitos híbridos e reforçados somente com polpa aos 28 dias de cura e após o envelhecimento acelerado foram submetidos aos ensaios físicos, mecânicos e microestruturais para acompanhamento do efeito da celulose nanofibrilada nas suas propriedades. Nos compósitos produzidos pelos dois processos aos 28 dias não houve diferença estatística para as propriedades físicas testadas, comparando-se os compósitos híbridos e os reforçados somente com polpa. No processo de sucção e prensagem, embora útil para ajustes na formulação e na cura do compósito híbrido, não se percebeu contribuição estatisticamente significativa da celulose nanofibrilada na formação de pontes de transferência de tensões, e, portanto sem o correspondente aumento na resistência mecânica dos compósitos. Nos compósitos extrudados, a celulose nanofibrilada atuou de modo a melhorar o comportamento mecânico do compósito híbrido em comparação ao compósito sem nanofibras. Esta melhoria pode estar associada à maior adesão entre as nanofibrilas e a matriz cimentícia, o que foi atestado pela análise microestrutural (MEV) dos compósitos. Após o envelhecimento acelerado os compósitos com e sem nanofibras produzidos pelos dois processos não apresentaram redução do desempenho mecânico, o que se atribui à menor alcalinidade provida pela carbonatação acelerada.Low elastic modulus vegetable fibers are known for their ability to increase the energy absorbed by cement based materials while they are loaded, especially during the post-crack stage. The use of cellulose nanofibers may contribute for toughening of brittle matrices and improving particle packing by both pore refining and crack intercepting at nanoscale, with the corresponding energy absorption. Nanofibrillated cellulose comes from a natural, abundant and renewable resources, it has good mechanical peformance and high specific surface, which contributes to improve the adhesion between the cement particles. These factors justify the use of nanofibrillated cellulose and give rise to an alternative nanoreinforcement for cement based materials. Thus, the aim of this work was the production of the nanofibrillated cellulose from bamboo organosolv pulp, establishing the best condition for its production and subsequent use as reinforcement in hybrid composites (both nano and micro-scale reinforcement) compared to composites reinforced with only microfibers (pulp), produced by the slurry vacuum dewatering followed by pressing and extrusion methods. The nanofibrillated cellulose was produced submitting unbleached and bleached pulps to 5, 10, 15 and 20 nanofibrillated cycles by the grinding method. Chemical, physical and mechanical tests were carried out to define the optimal condition to nanofibrillation. The unbleached nanofibrillated cellulose produced by 10 cycles was defined as the best option to be used in hybrid composites, since their greater modulus of elasticity and, because of their greater structural chemical stability, higher resistance to degradation in alkaline environments. The composites were subjected to accelerated carbonation curing process to mitigate thedegradation of fiber by reducing the matrix pH and also to refine the pores. The composites were subjected to accelerated aging process by means of 200 wet and dry cycles to assess their degradation. The hybrid composites and the composites reinforced only with pulp at 28 days and after accelerated aging were subjected to physico-mechanical and microstructural tests to study the effect of the nanofibrillated cellulose on their properties. There was no difference in the physical properties of the hybrid composites and composites reinforced with only pulp, produced by the two processes at 28 days. For the slurry vacuum dewatering followed by pressing process, although useful for adjustments in the formulation and cure hybrid composite, there was no statistically significant contribution of the nanofibrillated cellulose in the formation of stress transfer bridges, and therefore without a corresponding increase in the mechanical strength of the composites. For the extruded composites, the nanofibrillated cellulose improved the mechanical behavior of the hybrid composite compared to the composite without nanofiber. This improvement may be associated with greater adherence between the nanofibrils and the cement matrix, which was confirmed by microstructural analysis (SEM) of the composites. After accelerated aging, the composites with and without nanofibers produced by the two processes showed no reduction in mechanical performance, which is attributed to the lower alkalinity provided by the accelerated carbonation.
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Tirocchi, Martina. "Legno e bambù lamellare: materiali ecosostenibili a confronto nel caso studio di un garden office con prestazioni acustiche nella copertura". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23709/.
Abstract (sommario):
Il legno e il bambù lamellare sono materiali ecosostenibili con ottime prestazioni meccaniche. Entrambi i materiali derivano dalla lavorazione del materiale grezzo, i prodotti che ne derivano consentono di utilizzare il materiale in sezioni avendo caratteristiche migliori rispetto al materiale naturale. L’elaborato presenta le proprietà dei due prodotti confrontandoli tra loro e dimostrando che il bambù ingegnerizzato ha caratteristiche paragonabili o superiori a quelle del legno e dei prodotti a base di legno. Al fine di fornire un’analisi completa si realizza la progettazione di un garden office studiando sia il posizionamento interno sia esterno. La particolarità della copertura della struttura, rea-lizzata nel rispetto di parametri acustici ha fatto sì che venisse sviluppata un’alternativa nella progettazione in bambù lamellare come base per successive valutazioni acustiche.
Il risultato mette in evidenza come il bambù lamellare possa proporsi come materiale alternativo fornendo un’ulteriore prospettiva di sostenibilità.
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Melo, Santino Loruan Silvestre de. "Investigação das propriedades mecânicas e adesão interfacial dos compósitos de polipropileno virgem e reciclado reforçados com fibras e microfibras de bambu". reponame:Repositório Institucional da UFC, 2016. http://www.repositorio.ufc.br/handle/riufc/18446.
Abstract (sommario):
MELO, S. L. S. Investigação das propriedades mecânicas e adesão interfacial dos compósitos de polipropileno virgem e reciclado reforçados com fibras e microfibras de bambu. 2016. 81 f. Dissertação (Mestrado em Ciência de Materiais) – Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2016.Submitted by Hohana Sanders (hohanasanders@hotmail.com) on 2016-07-15T12:41:00Z No. of bitstreams: 1 2016_dis_slsmelo.pdf: 7577855 bytes, checksum: e0e18f673631f728b9c3f41d41bcde7d (MD5)
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The development of renewable and biodegradable materials is undoubtedly one of the most important of research to reduce environmental impacts. Therefore, the development of materials that can replace the use of materials from fossil fuels with raw material biodegradable, and almost unlimited achievement, makes plant fibers are a promising reinforcement to non-biodegradable materials. In this study, bamboo fibers were used to reinforce composites. In order to improve the fiber / matrix adhesion, chemical modifications were made on the fiber surface. Bamboo microfibers were also found to produce micro-composites and evaluate the mechanical stability of these modified micro-composites, which has the advantage of orientation in all directions of the material. The mechanical properties of mercerized and acetylated fibers and their composites with virgin and recycled polypropylene were obtained to analyze the stress at break and elastic modulus were affected after the surface treatment applied to the fiber. Analyses by SEM revealed the degradation of fibers depending on chemical modification, indicating the phase-matrix adhesion of composites and micro-composites. The FTIR fibers showed the efficacy of mercerization and acetylation surface with the appearance / disappearance of bands in the range of 3300 cm-1-3700 cm-1 and also at 1750 cm-1. With fiber tensile tests, it could be seen as chemical procedures affect the mechanical stability of the fibers. X-ray diffraction (XRD) were used to verify the degree of crystallinity of the fibers and relate it to their final mechanical properties. The crystallinity index with increased NaOH concentration (in mercerising solution) and decreased over time with acetylation. Tensile tests of fibers and composites revealed the influence of chemical modifications on the fibers. When For a higher concentration of NaOH in solution, the fibers had a higher maximum stress at rupture. However, for a longer acetylation was lower maximum stress at rupture of those fibers. For the virgin polypropylene composites uni- and bidirectional caused mechanical reinforcement fibers in some guidelines, such as the one-way 0 °. In all composites with recycled matrix, the fibers have been proven effective in the mechanical reinforcement of composites, reinforcing the maximum stress at break of up to 350% for composites bi-directional fibers. The modification procedure by acetylation in composites was effective as the mechanical reinforcement compared to composites with only mercerized fibers.
O desenvolvimento de materiais renováveis e biodegradáveis é uma das importantes vertentes de pesquisa para a diminuição dos impactos ambientais. Logo, o desenvolvimento de materiais que possam substituir o uso de materiais provenientes de fração destilada do petróleo por matéria prima biodegradável, e de obtenção quase ilimitada, faz com que as fibras de origem vegetal sejam um promissor reforço de para materiais não biodegradáveis. Neste estudo, fibras de bambu foram utilizadas para reforço de compósitos. No intuito de melhorar a adesão fibra/matriz, modificações químicas foram realizadas na superfície da fibra. Microfibras de bambu também foram obtidas para produzir microcompósitos e assim avaliar a estabilidade desses microcompósitos modificados, que possuem a vantagem de orientação em todas as direções do material. As propriedades mecânicas das fibras mercerizadas e acetiladas bem como seus compósitos de polipropileno virgem e reciclado foram obtidas para analisar principalmente a resistência e módulo de elasticidade. Estas propriedades foram afetadas após o tratamento superficial aplicado à fibra, apresentando os efeitos das modificações superficiais das fibras. As análises em MEV revelaram a degradação das fibras vegetais consoante modificação química, indicando a aderência fase-matriz dos compósitos e microcompósitos. Os FTIR’s das fibras revelaram a eficácia do procedimento de mercerização e acetilação superficial com o surgimento/desaparecimento de bandas na faixa de 3300 cm-1 a 3700 cm-1 e também em 1750 cm-1. Com os ensaios de tração das fibras, pôde-se perceber como os procedimentos químicos afetaram a estabilidade mecânica das fibras. As difrações de raios-X (DRX) foram utilizadas para verificar o grau de cristalinidade das fibras e relacioná-lo com as suas propriedades mecânicas finais. Para as fibras mercerizadas, o índice de cristalinidade, proporcionalmente, aumentou com concentração de NaOH (em solução de mercerização) e diminuiu com tempo de acetilação. Os ensaios de tração em fibras e compósitos revelaram a influência das modificações químicas nas fibras. Quando houve maior concentração de NaOH em solução, as fibras apresentaram uma maior resistência, entretanto, para um maior tempo de acetilação, foi menor a tensão máxima na ruptura dessas mesmas fibras. Para o polipropileno virgem, os compósitos uni e bidirecionais provocaram reforço mecânico em algumas orientações de fibras, como nas unidirecionais a 0°. Em todos os compósitos com matriz reciclada, as fibras se mostraram eficazes no reforço mecânico dos compósitos produzidos, reforçando a tensão máxima na ruptura em até 350% para compósitos com fibras bidirecionais. O procedimento de modificação por acetilação nos compósitos foi eficaz quanto ao reforço mecânico comparativamente aos compósitos com fibras apenas mercerizadas.
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Tranquilin, Ricardo Luis. "Estudo das propriedades microestruturais e ópticas do BaMoO4 processado em hidrotermal assistido por microondas /". Bauru : [s.n], 2009. http://hdl.handle.net/11449/88504.
Abstract (sommario):
Orientador: Élson LongoBanca: Fenelon Martinho Lima Pontes
Banca: Alberthmeiry Teixeira Figueiredo
- O Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi da Unesp
Resumo: O estudo das propriedades fotoluminescentes nos diferentes materiais tanto orgânicos e inorgânicos tem despertado muito o interesse da comunidade científica. Dentre os molibdatos, destacamos o molibdato de bário (BAMoO4) devido suas propriedades ópticas e termoelétricas que junto com suas emissões luminescentes no azul, verde e laranja o tornam um importante material. Neste trabalho, pós de molibdato de bário foram sintetizados pelo método de coprecipitação e processados a 140 ºC por diferentes tempos, em hidrotermal assistido por irradiação de microondas. A caracterização dos pós foi realizada através de difração de raios - X, espectroscopia Raman, absorção na região do infravermelho. As análises microestruturais e morfológicas destes pós foram realizadas através das técnicas de microscopia eletrônica de varredura por canhão de elétrons e microscopia de Transmissão. As propriedades ópticas foram verificadas por meio da espectroscopia na região do ultravioleta visível e medidas de fotoluminescência.
Abstract: The study of properties in different photoluminescent both organic and inorganic materials has attracted much interest form the scientific community. Among the molybdate,. the highlight of barium molybdate (BaMoO4) because their optical properties and thermoelectric that along with its luminescent emission in blue, green and orange make it an important material. In this work of barium molybdate were synthesized by co-precipitation method and processed at 140 ºC for diferent times in hydrothermal assisted by microwave irradiation. The characterization of powders was carried out by-ray diffraction - X, Raman spectroscopy, absorption in the infrared region. The micro structural and morphological analyses of these powders were performed using the techniques of field emission gun scanning electronic microscopy and by trasmission electronic microscopy. The optical properties were observed by spectroscopy in region the ultraviolet visible and measures of photoluminescence.
Mestre
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Cerrón, Oyague Tania Miluska. "Estrategias de arquitectura ecológica con bambú y el confort térmico, en el Parque Nacional del Manu, Cusco". Master's thesis, Universidad Ricardo Palma, 2016. http://cybertesis.urp.edu.pe/handle/urp/1022.
Abstract (sommario):
El presente trabajo de tesis desarrolla las estrategias de arquitectura ecológica con bambú y el confort térmico en el Parque Nacional del Manu, Cusco, específicamente para el Sector I de la Zona de Amortiguamiento. El estudio elige al bambú, por sus múltiples aportes en lo ambiental, económico y social y por ocupar una superficie significativa de especies nativas del genero Guadua en la Amazonia peruana, como principal componente para proponer estrategias de arquitectura ecológica que contribuyan a la conservación de un Área Natural Protegida de importancia a nivel mundial como lo es el Parque Nacional del Manu, el cual viene siendo amenazado por diversas acciones antrópicas, principalmente su Zona de Amortiguamiento, agravadas por los efectos del cambio climático y las necesidades económicas y de habitabilidad de la población. Estrategias que a su vez contemplen el confort térmico de las personas que habitaran en ese medio físico natural, con mínimo uso de energía para el caso del estudio. Se consideran dos ejes prioritarios para diseñar las estrategias: el Medio físico natural y el Uso del bambú, con la selección de tres especies locales una nativa del género Guadua y dos exóticas de los géneros Bambusa y Dendrocalamus; y el Diseño y Construcción. Cada uno con sus propios componentes y fases que se relacionan entre sí, planteando al mismo tiempo una correlación integrada entre todos. Estrategias que son aplicadas con la ejecución de un Modelo Arquitectónico – Cabaña de bambú, validado por los pobladores, y en el cual que se estiman las condiciones térmicas tomando como muestra representativa la evaluación de una de sus habitaciones, ambiente con ventilación natural, para ser comparada con las condiciones de térmicas de una habitación de una edificación local, con características similares en cuanto la ventilación y uso de materiales naturales y la sensación del poblador local. Para lo cual se plantea y desarrolla un sistema y cadena de procesos para la recolección y procesamiento de datos, utilizando para la predicción térmica el simulador virtual CBE Thermal Comfort Tool - estándar ASHRAE 55, con sus aplicaciones: modelo PMV y modelo Adaptativo de Confort. Con la estimación térmica se evalúa si se consideraron y aplicaron adecuadamente los lineamientos del primero y segundo eje. De esta manera se logra diseñar, emplear y validar las estrategias de arquitectura ecológica con bambú y el confort térmico en el PNM, Manu, Cusco.