Дисертації з теми "Processing of wool"
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Cruickshank, Amy Clare. "Nanostructured Metal Electrodes for Wool Processing and Electroanalysis." Thesis, University of Canterbury. Chemistry, 2007. http://hdl.handle.net/10092/3853.
Повний текст джерелаАнотація:
The research presented in this thesis firstly concerns the use of electrochemical techniques to develop approaches to wool processing which have a lower impact on the environment than conventional chemical methods. Wool is a sulfur rich substrate and current methods used in wool processing often rely on sulfur-based reducing agents such as metabisulfite. However, due to increasing concern over the environmental impacts of metabisulfite, alternative methods are of interest. Electrochemical techniques have been applied to the process of wool setting in the presence of thiol setting agents. Wool disulfide bonds are reduced during this process and the thiol setting agent is converted to the disulfide. Efficient conversion of the disulfide back to the thiol setting agent would allow catalytic amounts of thiols to be used in wool setting. The electroreduction of cystine and 2-hydroxyethyl disulfide has been examined at a range of metal and carbon electrodes to find efficient methods of generating the corresponding thiols, cysteine and 2-mercaptoethanol respectively. Gold and silver were identified as the most efficient electrode materials. In industrial wool processing, the use of large-scale metal electrodes is expensive and therefore, high surface area gold and silver nanoparticle electrodes were fabricated by electrochemically depositing the metals onto low-cost carbon substrates. The most efficient electrochemical system for generating the thiol setting agent involved the electroreduction of cystine at the gold nanoparticle electrode and this system was used to successfully demonstrate that wool setting can be achieved using relatively low concentrations of cysteine. Further research was carried out to investigate methods for the controlled preparation of metal nanoparticle electrodes and their utility for detecting hydrogen peroxide was examined. A simple and versatile approach for the preparation of tethered gold nanoparticle assemblies was developed by exploiting electrostatic interactions between citrate-capped gold nanoparticles and amine tether layers attached to carbon surfaces. The nanoparticle assemblies were optimised for the detection of hydrogen peroxide by selecting the size and density of electrostatically assembled nanoparticles. The number of amine functionalities on the surface and the assembly conditions controlled the nanoparticle density. Nanostructured palladium electrodes fabricated using vapour deposition methods to immobilise palladium nanoparticles directly onto carbon substrates were also examined for the electroanalysis of hydrogen peroxide.
2
Caunce, James Frederick Physical Environmental & Mathematical Sciences Australian Defence Force Academy UNSW. "Mathematical modelling of wool scouring." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Physical, Environmental and Mathematical Sciences, 2007. http://handle.unsw.edu.au/1959.4/38650.
Повний текст джерелаАнотація:
Wool scouring is the first stage of wool processing, where unwanted contaminants are removed from freshly shorn wool. In most scouring machines wool is fed as a continuous mat through a series of water-filled scour and rinse bowls which are periodically drained. The purpose of this project is to mathematically model the scour bowl with the aim of improving efficiency. In this thesis four novel models of contaminant concentration within a scour bowl are developed. These are used to investigate the relationships between the operating parameters of the machine and the concentration of contamination within the scour bowl. The models use the advection-diffusion equation to simulate the settling and mixing of contamination. In the first model considered here, the scour bowl is simulated numerically using finite difference methods. Previous models of the scouring process only considered the average steady-state concentration of contamination within the entire scour bowl. This is the first wool scouring model to look at the bowl in two dimensions and to give time dependent results, hence allowing the effect of different drainage patterns to be studied. The second model looks at the important region at the top of the bowl - where the wool and water mix. The governing equations are solved analytically by averaging the concentration vertically assuming the wool layer is thin. Asymptotic analysis on this model reveals some of the fundamental behaviour of the system. The third model considers the same region by solving the governing equations through separation of variables. A fourth, fully two-dimensional, time dependent model was developed and solved using a finite element method. A model of the swelling of grease on the wool fibres is also considered since some grease can only be removed from the fibre once swollen. The swelling is modelled as a Stefan problem, a nonlinear diffusion equation with two moving boundaries, in cylindrical coordinates. Both approximate, analytical and a numerical solutions are found.
3
Morgan, Laura. "Laser textile design : the development of laser dyeing and laser moulding processes to support sustainable design and manufacture." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/23176.
Повний текст джерелаАнотація:
This research developed new creative opportunities for textile design by investigating CO2 laser processing technology to achieve surface design and three-dimensional effects. A practice based and interdisciplinary textile design methodology was employed, integrating scientific and technical approaches with a reflective craft practice. It was found that the synthesis of design and science was imperative to achieving the research goal of evolving techniques that have opened new design opportunities for textile design whilst being viable and communicable for industrial and commercial application. Four distinct Laser Textile Design techniques were developed in this research including: a laser enhanced dyeing technique for wool and wool blends; Peri-Dyeing, a laser dye fixation technique; a laser moulding technique; and a laser fading linen technique.
4
Yusoff, Nukman bin. "A study on laser processing of wood." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/35072.
Повний текст джерелаАнотація:
The carbon dioxide (CO2) laser woodcutting has been used as an alternative to traditional wood machining processes. Smaller kerf width and non-contact machining were among the advantages and unique features of laser woodcutting. On the other hand, conventional wood machining such as sawing involves the application of force to separate chips from the workpiece until the desired size of workpiece is achieved. The focus of this research is to study and identify the quality of CO2 laser woodcutting. Various species of Malaysian wood have been used for this study. The initial experiment was carried out by studying the dimensional accuracy and material removal rate which reveals the trend of the laser woodcutting process.
5
Hietala, Maiju. "Extrusion processing of wood raw materials for use in wood-polymer composites." Licentiate thesis, Luleå tekniska universitet, Materialvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26720.
Повний текст джерелаАнотація:
The interest in wood-polymer composites and their use in different applications has been growing over the last 10-15 years. Environmental issues and demands on lower material costs are the driving forces behind the increasing use of renewable materials such as wood and other natural fibres as reinforcement in polymer composites. Wood flour consisting of small wood particles is currently used as the main wood raw material in commercial wood-polymer composites. However, the reinforcing potential of wood flour is limited. A better reinforcement could be achieved by using wood fibres with a higher aspect ratio as raw material, but individual fibres are seldom used in composite manufacturing due to processing problems and high cost. Therefore, the objective of the work was to study the possibility to use wood chips as raw material and separate individual fibres with higher aspect ratios from the wood chips during the composite manufacturing process. First, the effect of the extrusion process only on wood raw material was studied without a matrix polymer, and then composites using polypropylene as matrix were made. The main goal was to produce wood particles/fibres with high aspect ratio during the manufacturing of wood polymer composites. The effects of extrusion parameters, different screw configurations, raw materials and raw material pre-treatments were evaluated. The size of the separated wood particles and fibres was measured using optical fibre analysis methods. Microstructure of wood particles as well as the fractured surfaces of prepared composites were examined using electron microscopy. The mechanical properties of the composites were measured using flexural and impact testing. The results showed that wood chips can be used as raw material in a one-step manufacturing process of wood-polymer composites. Also, individual fibres with a higher aspect ratio than wood flour were separated from the wood chips with suitable processing conditionsGodkänd; 2011; 20110302 (ysko); LICENTIATSEMINARIUM Examinator: Professor Kristiina Oksman, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Diskutant: Associate Professor Roberts Joffe, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Tid: Torsdag den 7 april 2011 kl 13.00 Plats: E246, Luleå tekniska universitet
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Doroudiani, Saeed. "Microcellular wood-fibre thermoplastic composites, processing-structure-properties." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq41016.pdf.
Повний текст джерела
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Malatji, Pholoso. "Processing of wood and agricultural biomass for gasification." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2937.
Повний текст джерелаАнотація:
Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: Wood waste, when used for gasification is commonly pressed into briquettes, especially if no uniform particle size is available. This densification reduces problems of handling, storage and transportation and improves the combustion performance because of a more uniform fuel size. Briquettes have to be mechanically strong enough to be handled. Cohesive strength is provided by residual moisture and lignin present in the wood. The lignin acts as a natural binder. However, the briquetting process becomes more complicated if one wants to add other agricultural waste products that do not necessarily contain lignin as binders,, In this study we have investigated various briquetting process parameters, such as mixing ratios of briquettes containing wood chips, grape skins and chicken litter, moisture content and press time. The aim was to determine the optimum process parameters that allow the production of briquettes, containing a blend of biomaterials that are mechanically stable to allow further handling but yield high energy content at the same time.
AFRIKAANSE OPSOMMING: Wanneer houtafval vir vergassing gebruik word en die partikelgrootte daarvan varieer, word die materiaal normaalweg in ’n brikket gedruk. Brikketvorming vergemaklik opberging, hantering en vervoer. Weens die meer uniforme grootte en vorm van die brikkette is verbranding daarvan heelwat meer doeltreffend. Brikkette moet egter meganies sterk genoeg wees om hanteer te kan word. Die kohesiewe sterkte word deur residuele vog en lignien, wat as natuurlike bindmiddel in hout aanwesig is, verskaf. Indien ander materiale soos landbouafval, wat noodwendig geen lignien bevat nie egter gebruik word, word die brikketvormingsproses meer kompleks. In hierdie ondersoek is verskeie brikketvormingsparameters evalueer. Mengverhoudings van brikkette wat houtspaanders, druiwedoppe en hoendermis bevat, asook invloed van materiaalvoggehalte en druktyd is bestudeer. Die doel was om die optimale materiaal- en prosesparameters vas te stel wanneer ’n mengsel van biomateriale gebruik word om brikkette te lewer wat meganies sterk genoeg is maar steeds die hoogste energieopbrengs lewer.
Centre for Renewable and Sustainable Energy Studies
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Donnell, R. Douglas. "A microcomputer program to analyze wood supply and economic feasibility of wood processing facilities." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43848.
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Polec, Inga. "The processing and properties of oriented wood polypropylene composites." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511174.
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Vieira, Fábio Henrique Antunes [UNESP]. "Image processing through machine learning for wood quality classification." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/142813.
Повний текст джерелаАнотація:
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A classificação da qualidade da madeira é indicada para indústria de processamento e produção desse material. Essas empresas têm investido em soluções para agregar valor à matéria-prima, com o intuito de melhorar resultados, observando os rumos do mercado. O objetivo deste trabalho foi comparar Redes Neurais Convolutivas, um método de aprendizado profundo, na classificação da qualidade de madeira, com outras técnicas tradicionais de Máquinas de aprendizado, como Máquina de Vetores de Suporte, Árvores de Decisão, Regra dos Vizinhos Mais Próximos e Redes Neurais, em conjunto com Descritores de Textura. Isso foi possível através da verificação do nível de acurácia das experiências com diferentes técnicas, como Aprendizado Profundo e Descritores de Textura no processamento de imagens destes objetos. Foi utilizada uma câmera convencional para capturar as 374 amostras de imagem adotadas no experimento, e a base de dados está disponível para consulta. O processamento das imagens passou por algumas fases, após terem sido obtidas, como pré-processamento, segmentação, análise de recursos e classificação. Os métodos de classificação se deram através de Aprendizado Profundo e por meio de técnicas de Aprendizado de Máquinas tradicionais como Máquina de Vetores de Suporte, Árvores de Decisão, Regra dos Vizinhos Mais Próximos e Redes Neurais juntamente com os Descritores de Textura. Os resultados empíricos para o conjunto de dados das imagens da madeira serrada mostraram que o método com Descritores de Textura, independentemente da estratégia empregada, foi muito competitivo quando comparado com as Redes Neurais Convolutivas para todos os experimentos realizados, e até mesmo superou-as para esta aplicação.
The quality classification of wood is prescribed throughout the wood chain industry, particularly those from the processing and manufacturing fields. Those organizations have invested energy and time trying to increase value of basic items, with the purpose of accomplishing better results, in agreement to the market. The objective of this work was to compare Convolutional Neural Network, a deep learning method, for wood quality classification to other traditional Machine Learning techniques, namely Support Vector Machine (SVM), Decision Trees (DT), K-Nearest Neighbors (KNN), and Neural Networks (NN) associated with Texture Descriptors. Some of the possible options were to assess the predictive performance through the experiments with different techniques, Deep Learning and Texture Descriptors, for processing images of this material type. A camera was used to capture the 374 image samples adopted on the experiment, and their database is available for consultation. The images had some stages of processing after they have been acquired, as pre-processing, segmentation, feature analysis, and classification. The classification methods occurred through Deep Learning, more specifically Convolutional Neural Networks - CNN, and using Texture Descriptors with Support Vector Machine, Decision Trees, K-nearest Neighbors and Neural Network. Empirical results for the image dataset showed that the approach using texture descriptor method, regardless of the strategy employed, is very competitive when compared with CNN for all performed experiments, and even overcome it for this application.
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Vieira, Fábio Henrique Antunes. "Image processing through machine learning for wood quality classification /." Guaratinguetá, 2016. http://hdl.handle.net/11449/142813.
Повний текст джерелаАнотація:
Orientador: Manoel Cléber de Sampaio AlvesBanca: Fábio Minoru Yamaji
Banca: Ana Lúcia Piedade Sodero Martins Pincelli
Banca: André Luís Debiaso Rossi
Banca: Carlos de Oliveira Affonso
Abstract: The quality classification of wood is prescribed throughout the wood chain industry, particularly those from the processing and manufacturing fields. Those organizations have invested energy and time trying to increase value of basic items, with the purpose of accomplishing better results, in agreement to the market. The objective of this work was to compare Convolutional Neural Network, a deep learning method, for wood quality classification to other traditional Machine Learning techniques, namely Support Vector Machine (SVM), Decision Trees (DT), K-Nearest Neighbors (KNN), and Neural Networks (NN) associated with Texture Descriptors. Some of the possible options were to assess the predictive performance through the experiments with different techniques, Deep Learning and Texture Descriptors, for processing images of this material type. A camera was used to capture the 374 image samples adopted on the experiment, and their database is available for consultation. The images had some stages of processing after they have been acquired, as pre-processing, segmentation, feature analysis, and classification. The classification methods occurred through Deep Learning, more specifically Convolutional Neural Networks - CNN, and using Texture Descriptors with Support Vector Machine, Decision Trees, K-nearest Neighbors and Neural Network. Empirical results for the image dataset showed that the approach using texture descriptor method, regardless of the strategy employed, is very competi... (Complete abstract click electronic access below)
Resumo: A classificação da qualidade da madeira é indicada para indústria de processamento e produção desse material. Essas empresas têm investido em soluções para agregar valor à matéria-prima, com o intuito de melhorar resultados, observando os rumos do mercado. O objetivo deste trabalho foi comparar Redes Neurais Convolutivas, um método de aprendizado profundo, na classificação da qualidade de madeira, com outras técnicas tradicionais de Máquinas de aprendizado, como Máquina de Vetores de Suporte, Árvores de Decisão, Regra dos Vizinhos Mais Próximos e Redes Neurais, em conjunto com Descritores de Textura. Isso foi possível através da verificação do nível de acurácia das experiências com diferentes técnicas, como Aprendizado Profundo e Descritores de Textura no processamento de imagens destes objetos. Foi utilizada uma câmera convencional para capturar as 374 amostras de imagem adotadas no experimento, e a base de dados está disponível para consulta. O processamento das imagens passou por algumas fases, após terem sido obtidas, como pré-processamento, segmentação, análise de recursos e classificação. Os métodos de classificação se deram através de Aprendizado Profundo e por meio de técnicas de Aprendizado de Máquinas tradicionais como Máquina de Vetores de Suporte, Árvores de Decisão, Regra dos Vizinhos Mais Próximos e Redes Neurais juntamente com os Descritores de Textura. Os resultados empíricos para o conjunto de dados das imagens da madeira serrada mostraram que o método com De... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor
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Nordin, Lars-Olof. "Wood fiber composites : from processing and structure to mechanical performance." Doctoral thesis, Luleå : Univ, 2004. http://epubl.ltu.se/1402-1544/2004/09/.
Повний текст джерела
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Agrawal, Chandra Prakash. "Full-field deformation measurement in wood using digital image processing." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/43078.
Повний текст джерелаАнотація:
A digital image processing system was used to non-destructively measure the full-field deformation on aluminum and wood specimens loaded in compression and bending. The measurement technique consisted of creating a random speckle pattern on the specimen surface, recording images before deformation and after deformation, and computing the relative displacements of small image subsets. Two methods for producing speckle patterns on the specimens were studied: spray paint and adhesive-backed photographic film.
Baseline tests were conducted to evaluate the influence of signal noise on the measurement system. Uniform translation tests were conducted to evaluate the capability of the system for measuring finite motion. the technique was used to monitor the full-field deformation response of aluminum and wood specimens tested in bending and static compression. Moderate duration compression creep tests were conducted, on the wood specimens to investigate the suitability of the system for monitoring the creep response of materials. The results obtained from the two speckle techniques were also. compared. The results showed that for the magnification and speckle patterns tested displacement measurements smaller than 3.29x10-4 inch may be unreliable due to signal noise.
Master of Science
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Quinn, Rory. "Marine high-resolution reflection seismology : acquisition, processing and applications." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243092.
Повний текст джерела
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Kehbila, Atenkeng Taku. "Evaluation of primary wood processing residues for bioenergy in British Columbia." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27915.
Повний текст джерелаАнотація:
The growing energy demand in the world emphasizes the need for a more reliable energy source. To this end, a "fundamental” re-think is critical for an effective sustainable bioenergy production in the 21st century. BC has traditionally been the largest lumber and residue producing province in Canada, thus advancing bioenergy production in BC holds the potential to utilize residues from primary wood processing mills.
The main objectives of this study were: (1) to develop a database using important physical characteristics of residues from sawmills, and plywood mills in BC. (2) to estimate the total production, utilization and surpluses of primary residues within each forest region; and (3) to create a Dijkstra logarithm model partnered with a vector-based geographical information system (GIS) to investigate the optimal location of bio-based industrial plants using the available residues from BC’s mills.
Laboratory analysis of primary mill residues indicated that the higher heating values (HHV) ranged from 17 – 21.5 MJ/kg with a mean of 18.9MJ/kg. Ash contents were quite small for whitewood (0 – 2%) and higher for bark and hogfuel (2 – 6.5%) with a mean of 1.6%. The moisture content (MC) on wet mass basis ranged from 5 – 317% with a mean of 105%. The basic density ranged from 120 – 1151 kg/m³ with a mean of 352 kg/m³. The average particle size (Dp₅₀) of the residues ranged from 0.2 – 49.7 mm.
Analyses of the availability of primary mill residues revealed that due to the demands of the pulp and paper industry, there were no available residues in BC for bioenergy production in 2006. Consequently, an artificial situation was created in order to demonstrate the potential benefits of the GIS-Dijkstra integrated modeling framework to determine the most preferred locations for bioenergy plants. Under this hypothetical scenario surplus residue generated in the Southern forest region had the lowest residue cost for bark at $15/BDt followed the coastal forest region at $46/BDt and the Northern forest region at $51/BDt. While the Southern interior forest region still had the cheapest whitewood residue cost at $31/BDt followed the Northern forest region at $78/BDt and the coastal forest region at $84/BDt.
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Anderson, Scott Powell. "Wood fiber reinforced bacterial biocomposites effects of interfacial modifers and processing on mechanical and physical properties /." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/S_Anderson_100507.pdf.
Повний текст джерела
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Schneider, Christian, and Oscar Andersson. "Examining Levels of Automation in the Wood Processing Industry - A case study." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Industriell organisation och produktion, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-33713.
Повний текст джерелаАнотація:
Companies operating in the wood processing industry need to increase their productivity by implementing automation technologies in their production systems. An increasing global competition and rising raw material prizes challenge their competitiveness. Yet, too extensive automation brings risks such as a deterioration in situation awareness and operator deskilling. The concept of Levels of Automation is generally seen as means to achieve a balanced task allocation between the operators’ skills and competences and the need for automation technology relieving the humans from repetitive or hazardous work activities. The aim of this thesis was to examine to what extent existing methods for assessing Levels of Automation in production processes are applicable in the wood processing industry when focusing on an improved competitiveness of production systems. This was done by answering the following research questions (RQ): RQ1: What method is most appropriate to be applied with measuring Levels of Automation in the wood processing industry? RQ2: How can the measurement of Levels of Automation contribute to an improved competitiveness of the wood processing industry’s production processes? Literature reviews were used to identify the main characteristics of the wood processing industry affecting its automation potential and appropriate assessment methods for Levels of Automation in order to answer RQ1. When selecting the most suitable method, factors like the relevance to the target industry, application complexity or operational level the method is penetrating were important. The DYNAMO++ method, which covers both a rather quantitative technical-physical and a more qualitative social-cognitive dimension, was seen as most appropriate when taking into account these factors. To answer RQ 2, a case study was undertaken at a major Swedish manufacturer of interior wood products to point out paths how the measurement of Levels of Automation contributes to an improved competitiveness of the wood processing industry. The focus was on the task level on shop floor and concrete improvement suggestions were elaborated after applying the measurement method for Levels of Automation. Main aspects considered for generalization were enhancements regarding ergonomics in process design and cognitive support tools for shop-floor personnel through task standardization. Furthermore, difficulties regarding the automation of grading and sorting processes due to the heterogeneous material properties of wood argue for a suitable arrangement of human intervention options in terms of work task allocation. The application of a modified version of DYNAMO++ reveals its pros and cons during a case study which covers a high operator involvement in the improvement process and the distinct predisposition of DYNAMO++ to be applied in an assembly system.
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Cohen, David H. "The adoption of innovative wood processing technologies in the building products industry." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54508.
Повний текст джерелаАнотація:
The strategic importance of the adoption of innovative processing technologies was analyzed for building products businesses. This study examined the two components of wood building products businesses: the structural panel industry and the softwood Iumber industry. To ensure that the relevance of adopting of innovative processing technologies was examined within an accurate contextual environment, additional important strategies and performance were also measured.
A mail survey of the seventy-five largest North American producers of these two products provided the primary data necessary to investigate the strategic importance of process technology adoption, forward vertical integration, relative market share, grade sector focus, and investment intensity on firm performance as measured by profitability surrogates and changes in relative market share. This survey collected direct measures of the proportion of 1987 production produced by respondent firms that used controlled distribution channels and each of twentythree processes indicative of innovative technologies in the manufacture of building products. Information concerning the other strategic and performance factors was collected from secondary data sources.
Results indicate that the adoption of innovative processing technologies has a positive impact on firm profitability. Investment intensity and grade sector focus also contributed to superior profitability. Forward vertical integration, and relative market share had no impact in differences between performance levels for the firms studied.
Technologies were examined for underlying dimensions that group different process technologies together. Firms were clustered according to their level of adoption of innovative processing technologies and these clusters were then described according to a variety of firm-dependent characteristics, strategies, and performance measures. A strategy-performance model was developed for standardized, industrial product-markets and empirically tested using the data collected for the building products industry as an industry representative of this type of competitive environment.Ph. D.
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MAZZANTI, Valentina. "Rheology of Wood Polymer Composites." Doctoral thesis, Università degli studi di Ferrara, 2015. http://hdl.handle.net/11392/2389015.
Повний текст джерелаАнотація:
Wood plastic composite (WPC) is a material composed of a thermoplastic matrix filled with wood fibers at different concentrations. This material is widely used for decking and automotive applications. With respect to wood it requires less maintenance, shows better durability in wet environment and can be obtained from recycled materials. With respects to plastics the main advantage is its lower cost.
The aim of this thesis has been to investigate the mechanical and rheological properties of PP based Wood Polymer Composites.
The mechanical characterization has shown that wood fibers make the composite stiffer without lowering strength values too much, while thermal properties have confirmed that the processing window for this material is rather narrow, being limited upwards by wood fiber degradation and downwards by the melting temperature, which is around 165°C.
Commercial PP-based WPCs filled with different filler concentration have been investigated with an off – line rheometer in oscillation mode at 170°C. Complex viscosity increases with the percentage of fibers. All materials show a shear-thinning behaviour with similar slopes of the flow curves and neat PP also displays a Newtonian plateau at low shear rates. The test temperature is imposed by the requirement of performing the test within the linear viscoelasticity region, but the data that are measured are not directly useful for processing, as a convenient processing temperature should be around 195°C.
In order to obtain the WPC viscosity at such temperatures, a model that uses the WPC viscosity measured at 170°C at various wood quantities and of neat PP viscosity measured at various temperatures is proposed. The main hypothesis of this model is that the effects of temperature and filler content on the composite viscosity are disjoint. These measurements permit to create shift factors that allow to estimate the WPC viscosity on the basis of neat PP viscosity, temperature and fibers content.
In order to validate the model, flow curve of 30%wt. and 70%wt. WPC at 195°C have been measured with an instrumented extruder slit die that allows the determination of the flow characteristics of the material in a condition that is very similar to the actual processing conditions. The slit die, connected with a single screw extruder, has a channel that is 50 mm wide and 105 mm long. Three heights are used for the Mooney procedure and three pressure transducers are flush mounted along the slit to eliminate the need for the Bagley correction.
The results show that the viscosity curve for the 30% wt. WPC validates the model presented with a reasonably good agreement. Since the agreement for the 70% wt. is less justified and such a material displays a marked yield stress, we can conclude that it is the yield stress that is probably the single issue that makes the present model questionable.
In this regard, a future work that we propose is to modify the model by selecting a Carreau-Yasuda model with an yield stress to account for the increase in the viscosity at low shear rates
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Mertens, Oliver [Verfasser], and Andreas [Akademischer Betreuer] Krause. "Performance and processing evaluation of thermoplastic wood fiber composites / Oliver Mertens ; Betreuer: Andreas Krause." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2018. http://d-nb.info/1160675821/34.
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Johansson, Jimmy. "Mechanical processing for improved products made from Swedish hardwood." Doctoral thesis, Växjö : Växjö University Press, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-2457.
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Packianather, Michael S. "Design and optimisation of neural network classifiers for automatic visual inspection of wood veneer." Thesis, Cardiff University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323160.
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Robertson, Kimberly Ann. "Estimating regional supply and delivered cost of forest and wood processing biomass available for bioenergy." Thesis, University of Canterbury. Forestry, 2006. http://hdl.handle.net/10092/1106.
Повний текст джерелаАнотація:
New Zealand has ratified the Kyoto Protocol and agreed to reduce greenhouse gas emissions to 1990 levels in the first commitment period 2008-2012. Energy generated from renewable sources, such as New Zealand plantation forests and wood processing sites, is considered greenhouse gas neutral. But the use of biomass for bioenergy in New Zealand is very small. Some of the reasons for this include a lack of information about the future fuel supply and delivered cost. This thesis aims to provide a methodology to estimate biomass fuel availability and the delivered cost, of a range of forest and wood processing sources within a district, and to analyse the impact of harvest age, harvesting practices, terrain, collection and chipping costs, opportunity cost and transport costs on the availability and delivered cost of biomass for bioenergy. The six biomass streams included were chiplogs, forest landing residues, cutover residues, sawdust, bark and chip. The methodology was developed based on an area in Canterbury, and tested on an area in the Nelson/Marlborough region. It utilises forest growth models, Geographic Information Systems and Microsoft Excel. Growth models allow the analysis to be customised to a particular area or region, while the use of GIS allows the model to take spatial aspects (for example slope and transport distance) into consideration. Developing the overall framework within Excel allows easy analysis of the results and changes to the underlying assumptions. Opportunity costs make up a large proportion of the total cost of delivery for the chiplog, sawdust, bark and chip biomass and need to be included in any estimate of cost for these biomass streams. The logistic system chosen for collecting and chipping the forest residues has a large impact on their delivered cost as do the transport costs. However transport cost is not the most significant influence on the delivered cost of other biomass streams. The use of biomass for electricity generation only is not currently economic in either of the areas analysed. The use of biomass for heat production is currently economic if compared to the electricity purchase price.
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Penniall, Christopher Leigh. "Feasibility Study into the Potential for Gasification Plant in the New Zealand Wood Processing Industry." Thesis, University of Canterbury. Chemical and Process Engineering, 2008. http://hdl.handle.net/10092/2159.
Повний текст джерелаАнотація:
The purpose of this research was to investigate the feasibility of installing gasification based combined heat and power plants in the New Zealand wood processing industry. This is in accordance with Objective Four of the BIGAS Consortium.
This thesis builds on previous work on Objective Four (Rutherford, 2006) where integration into MDF (Medium Density Fibreboard) was investigated. The previous research identified the most suitable form of combined heat and power was a BIG-GE (Biomass Integrated Gasification Gas Engine) process, due to both lower capital investment and overall breakeven electricity production cost. This technology has therefore been adopted, and the investigation has been carried further in this research to incorporate integration into sawmills and LVL (Laminated Veneer Lumber) plants.
It is recognised, however, especially when reviewing overseas successes and failures, that the base economics are only one factor in the feasibility of a plant. The research, therefore, has moved further to investigate New Zealand policy, the power market, lower capital alternatives and novel methods of integration.
The conclusion of the study is gasification based combined heat and power plants in the New Zealand wood processing industry can be equal or better in economic terms than other forms of renewable generation, however, the application is very niche. Lower capital cost alternatives, stable and low priced biomass feed and a favourable power market in regards to distributed generation is key to the viability of such a plant.
Government policy is favourable towards biomass gasification due to the target of 90% electrical generation by renewable resources by 2025. Distributed generation is also encouraged in the Government’s forward strategy. However, the technology has advanced further overseas due to capital grants and a premium paid for ‘green’ electricity. While the technology may be economic in its own right, active government support would lower the perceived risk increasing the likelihood of an investor taking interest in an initial project.
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Kuzmin, Oleg, and Volodymyr Isaienko. "Development of resource-saving technologies for processing wood waste for the production of alcoholic beverages." Thesis, European Scientific Platform, 2020. https://er.nau.edu.ua/handle/NAU/44362.
Повний текст джерелаАнотація:
Waste reduction is a key challenge for the sustainable development of the food industry, so reducing it is a pressing issue for most businesses in the industry. Waste recycling and utilization is a strategic goal for each company, which involves the involvement of innovative technologies based on the evaluation of decisions in reducing the cost of finished products, minimizing raw material losses, increasing the yield of finished products.
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Lemaster, Richard L. "Development of an Optical Profilometer and the Related Advanced Signal Processing Methods for Monitoring Surface Quality of Wood Machining Applications." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-09282004-152158/.
Повний текст джерелаАнотація:
The research described here provides the technology and theory to quantify surface quality for a variety of wood and wood-based products. This technology provides a means of monitoring trends in surface quality which can be used to discriminate between Agood@ products and Abad@ products (the methods described in this research are not intended to provide ?grading? of individual workpieces) as well as provide information to the machine operator as to the source of poor quality machined surfaces. The analysis can be done either on-line at industrial speeds or off-line as a periodic quality control tool. Although the surface quality can be quantifiably measured, the determination of the best feature from the surface profile (root mean square, peak amplitude, average wavelength, frequency content, Joint Time and Frequency Analysis (JTFA) and Wavelet Analysis results, etc.) for the quantification of surface Adefects@ is highly dependent on the application. This research consisted of three broad areas: (1) determination of an optimal hardware configuration for both laboratory and industrial surface scans of wood products, (2) determination of the optimal set of surface descriptors as well as the development of advanced signal processing techniques such as the wavelet transform to accurately describe the quality of a surface as well as provide information to the machine operator on the cause of the loss of surface quality, and (3) development of a software interface to distill the advanced signal processing techniques into a readily obtainable and readable format for the machine operator as well as provide assistance for process decisions.
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Du, Plessis Johan de Villiers. "Investigation into the use of meta-heuristics in the optimisation of log positioning during sawmill processing." Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5209.
Повний текст джерелаАнотація:
Thesis (MSc (Forest and Wood Science))--University of Stellenbosch, 2011.ENGLISH ABSTRACT: The percentage yield of sawn timber recovered from logs has a large influence on the profitability of a sawmill. The positioning of the log as it is fed into the primary breakdown saw is one of the factors that impacts on the volume recovery percentage. The log’s position can be adjusted by changes in rotation, offset and skewness and depending on the ranges and increments used for these variables, the number of possible combinations can become substantial. In a sawmill the time available to assess possible log positions is limited and different strategies can be followed to arrive at an optimal or close‐to‐optimal positioning solution without an exhaustive evaluation of solutions. Meta‐heuristics are sometimes used to arrive at solutions for combinatorial optimisation problems in a limited time. The effectiveness of this approach on the optimisation of timber volume recovery based on log form is evaluated in this study using sawmill simulation data of sixty SA pine logs. A new meta‐heuristic, for convenience named the Tentacle algorithm, was developed specifically for the problem of log positioning optimisation. The results obtained with the Tentacle algorithm was compared with results from three existing meta‐heuristics i.e. the Simulated Annealing algorithm, the Population Based Incremental Learning algorithm and the Particle Swarm Optimisation algorithm, in terms of its efficiency and effectiveness in finding good log positioning solutions in a limited time. A fifth method, that of exhaustively searching smaller, high quality areas around the centered and “horns‐up” and “horns‐down” positions in the search space was compared to that of using the meta‐heuristic algorithms. In terms of volume recovery, the Tentacle algorithm performed, on average, the best of the four algorithms evaluated. However, exhaustive searches in the smaller, high quality areas in the search space, outperformed the algorithms.
AFRIKAANSE OPSOMMING: Die herwinningspersentasie van gesaagde planke uit saagblokke het ‘n groot invloed op die winsgewendheid van ‘n saagmeul. Die posisionering van die blok in die primêre saag is een van die faktore wat die herwinningspersentasie beïnvloed. Die blok se posisie kan verstel word deur veranderinge in rotasie, oplyning en skeefheid. Afhangend van die veld ‐en inkrementgrootte kan die hoeveelheid moontlike kombinasies beduidend wees. In ‘n tipiese saagmeul is die beskikbare tyd om moontlike posisies te evalueer beperk en verskeie strategieë kan gevolg word om optimale of nabyoptimale kombinasies te bereik sonder om alle moontlike kombinasies te evalueer. Meta‐heuristieke word soms gebruik om in ‘n beperkte tyd oplossings te vind vir kombinatoriese optimeringsprobleme. Die doeltreffendheid van hierdie metode by die optimering van herwinningspersentasie gebaseer op blokvorm is in hierdie studie ondersoek. Dit is met behulp van saagmeulsimulasiedata soos van sestig SA dennehoutblokke verkry, uitgevoer. ‘n Nuwe meta‐heuristiek, genaamd die Tentakelalgoritme, is tydens hierdie studie spesifiek vir die probleem van blokposisie‐optimering ontwikkel. Die resultate verkry met die Tentakelalgoritme is vergelyk met drie bestaande meta‐heuristieke, nl. die “Simulated Annealing”‐algoritme, die “Population Based Incremental Learning”‐algoritme en die “Particle Swarm Optimisation”‐algoritme in terme van doeltreffendheid om goeie blokposisies in ‘n beperkte tyd te vind. ‘n Vyfde metode, die gebruik van ‘n volledige ondersoek van verkleinde versamelings, rondom hoë‐kwaliteit areas in die soekarea, is vergelyk met die gebruik van die meta‐heuristieke. Hierdie hoë‐kwaliteit areas word gevind rondom die gesentreerde “horns‐up” en “horns‐down” posisies. Die Tentakelalgoritme het gemiddelde die beste herwinningsresultate van die vier meta‐heuristieke wat ondersoek was gelewer. Die volledige ondersoek van verkleinde versamelings in die hoë kwaliteit areas het egter die meta‐heuristieke oortref.
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Paulrud, Susanne. "Upgraded biofuels-effects of quality on processing, handling characteristics, combustion and ash melting /." Umeå : Unit of Biomass Technology and Chemistry, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a449.pdf.
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Lindner, Berndt Gerald. "Determining optimal primary sawing and ripping machine settings in the wood manufacturing chain." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86672.
Повний текст джерелаАнотація:
Thesis (MEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: For wood manufacturers around the world, the single biggest cost factor is known to be its raw material. Thus maximum utilisation, specifically volume recovery of this raw material, is of key importance for the industry. The wood products industry consists of several interrelated manufacturing steps for converting trees into logs and logs into finished lumber. At most primary and secondary wood processors the different manufacturing steps are optimised in isolation or based on operator experience. This can lead to suboptimal decisions and a substantial waste of raw material. The objective of this study was to determine the optimal machine settings for two interrelated operations, namely the sawing and ripping operations which have traditionally been optimised individually. A model, having two decision variables, was developed which aims to satisfy market demand at a minimal cost. The first decision was how to saw the log supply into different thicknesses by choosing specific sawing patterns. The second was to decide on a rip saw’s settings, namely part priority values, which determines how the products from the primary sawing operation are ripped into products of a certain thickness and width. The techniques used to determine the machine settings included static simulation with the SIMSAW software to represent the sawing operation and mixed integer programming to model the ripping operation. A metaheuristic, namely the Population Based Incremental Learning algorithm, was the link between the two operations and determined the optimal settings for the combined process. The model’s objective function was formulated to minimise the cost of production. This cost included the raw material waste cost and the over or under production cost. The over production cost was estimated to include the stock keeping costs. The under production cost was estimated as the buy-in cost of purchasing the under supplied products from another wood supplier. The model performed well against current decision software available in South Africa, namely the Sawmill Production Planning System package, which combines simulation (SIMSAW) and mixed integer programming techniques to maximise profit. The model added further value in modelling and determining the ripping priority settings in addition to the primary sawing patterns.
AFRIKAANSE OPSOMMING: Die grootste enkele koste vir houtprodukvervaardigers wêreldwyd is dié van hulle roumateriaal. Die maksimale gebruik van rou materiaal, of volume herwinning, is dus van primêre belang vir hierdie industrie. Die vervaardigingsproses in die houtprodukte-industrie bestaan uit ‘n verskeidenheid interafhanklike stappe om bome na stompe te verwerk en stompe na eindprodukte. By meeste primêre -en sekondêre houtvervaardigers word die verskillende vervaardigingsstappe in isolasie ge-optimeer. Hierdie praktyk lei tot sub-optimale besluite en ‘n vermorsing van roumateriale. Die doelwit van hierdie studie was om die optimale masjienverstellings vir twee interafhanklike prosesse, die primêre -en kloofsaag prosesse, te bepaal. Tradisioneel word hierdie twee prosesse individueel optimeer. ‘n Model met twee besluitnemingsveranderlikes is ontwikkel wat poog om die markaanvraag te bevredig teen ‘n minimum koste. Die eerste besluit was watter saagpatroon gekies moet word om die stompe in die regte dikte produkte te saag. Die tweede besluit was wat die kloofsaagstellings, ook bekend as prioriteitswaardes, moet wees sodat die regte wydte produkte gesaag word. Die tegnieke wat gebruik is sluit statiese simulasie met SIMSAW sagteware in om die primêre saagproses te modelleer en gemengde heelgetalprogammering (“mixed integer programming”) om die kloofsaagproses te modelleer. ‘n Metaheuristiek genaamd die “Population Based Incremental Learning” algoritme,was die skakel tussen die twee operasies om die optimale masjienstellings vir die proses te bepaal. Die model se doelfunksie was geformuleer om die koste van produksie te minimeer. Hierdie koste sluit die roumateriaal afvalkoste en die kostes van oor -en onderproduksie in. Die oorproduksiekoste was ‘n skatting van die voorraadkostes. Die onderproduksiekoste was ‘n skatting van die koste om voorraad van ‘n ander verskaffer aan te koop. Die model het goed opgeweeg teen die beskikbare besluitnemingssagteware in Suid Afrika, die “Sawmill Production Planning System”, wat ‘n kombinasie van SIMSAW en ‘n gemengde heelgetalprogrammeringstegniek is. Die model het verder waarde toegevoeg deur die kloofsaag se prioriteitswaardes te modelleer saam met die primêre saagpatrone.
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Mardikar, Yogesh Mukesh. "Establishing baseline electrical energy consumption in wood processing sawmills a model based on energy analysis and diagnostics /." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5412.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains xvi, 222 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 203-207).
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Gantenbein, Daniel. "Development of mineral particle surfaces for the adsorption of pitch from wood processing and recycling of paper." Thesis, University of Plymouth, 2012. http://hdl.handle.net/10026.1/1175.
Повний текст джерелаАнотація:
During the production of paper in paper mills, detrimental wood resin is released into the water circuit of the mill during the pulping process of the wood into fibres. This wood resin, termed pitch, can detrimentally deposit on the paper and on the paper machine equipment. The deposits mark the paper or can lead to a tear of the paper web involving a loss of output and a reduction in paper quality. Furthermore, the wood resinous compounds in paper mill effluents need to be reduced in order to minimise their toxic effects on water organisms. Talc has been the benchmark for many years as a mineral additive in pitch control. Since the papermaking process has changed over the years, the concept of mineral addition needs to be redefined and adopted towards the new circumstances. By understanding the fundamentals behind the adsorption of wood resin compounds from aqueous systems on to talc new mineral additives can be developed. A model for the determination of the aspect ratio of platy and rod-like particles has been developed, based on commonly available characterisations such as particle size, specific surface area and shape. It was found that the adsorption capacity of a mineral is directly proportional to its specific surface area, but only within its mineral family. Including the effect of surface hydrophilicity and hydrophobicity allowed fine tuning of the adsorption capacity of newly developed calcium carbonate grades. Furthermore, size exclusion effects, in porous, high surface area modified calcium carbonate, were seen to hinder complete coverage of the surface area by wood resin. With increasing pH, the adsorption efficiency of talc for colloidal wood resin was found to decrease. Under these alkaline conditions, which are common in modern paper making processes, talc preferentially adsorbed dissolved species. The use of the newly developed surface treated and modified calcium carbonates allowed more efficient adsorption of the colloidal fraction and, therefore, represent an efficient alternative to talc in pitch control. An increase in temperature led to an increased adsorption capacity of talc. This observation indicates the type of interaction tat controls the adsorption of hydrophobic pitch particles onto talc, i.e. the entropically favoured release of water from the hydrophobic talc surface as well as the hydrophobic methylene backbone of the hemicellulose.
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Svedberg, Urban. "Fourier Transform Infrared Spectroscopy in Industrial Hygiene Applications : Assessment of Emissions from and Exposures in Wood Processing Industries." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4225.
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Srikanteswara, Srikathyayani. "Feature Identification in Wooden Boards Using Color Image Segmentation." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35600.
Повний текст джерелаАнотація:
Many different types of features can appear on the surface of wooden boards, lineals or parts. Some of these features should not appear on the surfaces of wood products. These features then become undesirable or removable defects for those products. To manufacture these products boards are cutup in such a way that these undesirable defects will not appear in the final product. Studies have shown that manual cutup of boards does not produce the highest possible yield of final product from rough lumber. Because of this fact a good deal of research work has been done to develop automatic defect detection systems. Color images contain a lot of valuable information which can be used to locate and identify features in wood. This is evidenced by the fact that the human color vision system can accurately locate and identify these features. A very important part of any automatic defect detection system based wholly or impart on color imagery is the location of areas that might contain a wood feature, a feature that depending on the product being manufactured may or may not be a defect. This location process is called image segmentation. While a number of automatic defect detection systems have been proposed that employ color imagery, none of these systems use color imagery to do the segmentation. Rather these systems typically average the red, green, and blue color channels together to form a black and white image. The segmentation operation is then performed on the black and white image. The basic hypothesis of this research is that the use of full color imagery to locate defects will yield better segmentation results than can be obtained when only black and white imagery is used. To approach the color wood image segmentation problem, two conventional clustering procedures were selected for examination. Experiments that were performed clearly showed that these procedures, ones that are similar in flavor to other unsupervised clustering methods, are unsuitable for wood color image segmentation. Based on the experience that was gained in examining the unsupervised clustering procedures, a model based approach is developed. This approach is based on the assumption that the distribution of colors in clear wood is Gaussian. Since boards that are used by the forest products secondary manufacturing industry are all such that most of their surface area is clear wood, the idea is to use the most frequently occurring colors, i.e., the ones that must represent the most likely colors of clear wood, to estimate the mean and covariance of the Normal density function specifying the possible colors of clear wood. Deviations from this model in the observed histogram are used to identify colors that must be caused by features other than clear wood that appear on the surface of the board.Master of Science
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Axelsson, Maria. "Image analysis for volumetric characterisation of microstructure /." Uppsala : Centre for Image Analysis, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200919.pdf.
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Berková, Kristýna. "Processing, structure and properties of composites based on natural fillers and strereoregular polyolefins." Thesis, Clermont-Ferrand 2, 2013. http://www.theses.fr/2013CLF22386/document.
Повний текст джерелаАнотація:
Ce travail porte sur l’étude des composites à base de polypropylène et de farine de bois. Seuls des composites à base d’une matrice polypropylène et de fibres végétales ont été mis en oeuvre sans aucun recours à quelque agent comptabilisant que ce soit. En premier lieu nous avons regardé l’influence de la viscosité initiale de la matrice polypropylène sur la processabilité des biocomposites en utilisant des polymères de grades variés. Puis nous avons étudié l’influence de la nature et de la concentration de la farine en utilisant des farines de pin (bois mou) et de chêne (bois dur). Enfin, une attention spécifique a été portée sur la possibilité de nucléation en phase Beta de la matrice polypropylène en présence de fibres végétales. Des polypropylènes β-Nucléés ainsi que des farines ayant subies des extractions par des solvants de leurs composés volatils ont été utilisées. Les mélanges obtenus ont été testés au moyen de la viscoélasticité à l’état fondu pour mettre en évidences les effets d’interaction charges-Matrices et par des mesures de diffraction aux rayons X ainsi que d’analyse thermique différentielle pour la caractérisation de leurs morphologies cristallinesThis doctoral thesis is focused on composites based on polypropylene and wood flour. Firstly, the experimental work deals with preparation of composites based on wood flour with various concentrations and isotactic polypropylene with various melt flow indexes. In terms of this study, one polypropylene, which can have also practical use, was chosen. Further, this polypropylene is investigated with various types and concentrations of wood flour. Also, the attention is devoted to the modification of polypropylene by a specific β-Nucleating agent. The differences are compared and described between the composites with neat and nucleated polypropylene. Further, the work is focused on solvent extraction of wood flour. The effect of extraction and solvent of wood flour is also examined in composites with neat and nucleated polypropylene. On prepared composites, the rheological, structural and thermal properties are studied. These properties differ depending on specific type of wood flour, its concentration and specific type of polypropylene
Předložená doktorská práce je zaměřena na kompozity polypropylenu a dřevní moučky. V experimentální části práce jsou připraveny kompozity s různými koncentracemi plniva a izotaktických polypropylenů s různými indexy toku taveniny. Na základě této studie je vybrán jeden konkrétní polypropylen, který může mít v kombinaci s dřevní moučkou i praktické využití. Tento polypropylen je dále zkoumán s různými druhy a koncentracemi dřevní moučky. Pozornost je také kladena na úpravu vlastností izotaktického polypropylenu užitím specifického β-nukleačního činidla. Jsou porovnávány a popisovány rozdíly mezi kompozity s čistým a nukleovaným polypropylenem. Práce se dále zabývá extrakcí dřevní moučky v rozpouštědle. Je studován vliv extrakce a rozpouštědla dřevní moučky na vlastnosti připravených kompozitů. Byly studovány reologické, strukturální a tepelné vlastnosti, které se lišily v závislosti na zvoleném typu plniva, jeho koncentraci a typu polymerní matrice
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Savičiūnaitė, Ingrida. "Medžio apdirbimo įmonės Šiauliuose sovietmečiu." Bachelor's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130819_110626-07266.
Повний текст джерелаАнотація:
Prasidėjus antrajai sovietinei okupacijai, Lietuva prievarta inkorporuota į Sovietų Sąjungą. Pramonė Lietuvoje po karo buvo itin skurdi. Todėl kreiptas didelis dėmesys jos atstatymui. Medžio apdirbimo pramonė Šiaulių mieste sovietmečiu reikšmingesnio valdžios dėmesio nesulaukė. Po karo trūko miško medžiagos, o aplink Šiaulius miškų beveik nebuvo (iškirto okupacinė nacių kariuomenė). Kaip vieną pagrindinių medžio apdirbimo įmonių Šiaulių mieste galima išskirti medžio apdirbimo kombinatą, kuris įkurtas 1944 m., susivienijus Navicko lentpjūvei, įmonei „Guoba“, lentpjūvei – malūnui „Skirpstas“, Lazdinio lentpjūvei. Kombinatas buvo pavaldus Lietuvos SSR Miškų pramonės komisariatui. 1949 vasario 10 d. Lietuvos miškų ir popieriaus pramonės ministerijos įsakymų likviduotas Šiaulių baldų fabrikas ,,Rūdė“, kuris įjungtas į Šiaulių medžio apdirbimo kombinato sudėtį. 1974 sausio 8 d. Lietuvos SSR baldų ir medžio apdirbimo pramonės ministerijos įsakymu buvo reorganizuotas kombinatas į Šiaulių baldų susivienijimą ,,Venta“.As the second Soviet occupation commenced, Lithuania was forcibly incorporated in the Soviet Union. Industry in Lithuania was very poor after the war. Therefore a lot of attention was paid to rebuilding it. Wood processing industry in Šiauliai City did not receive any significant attention from the authorities during the Soviet period. There was a lack of timber after the war and there almost were no forests nearby Šiauliai (they were cut down by the occupant Nazi army). A wood processing factory established in 1944 upon merger of Navickas Sawmill, Company “Guoba”, Sawmill – Mill “Skirpstas”, Lazdinis Sawmill can be distinguished as one of the major wood processing companies in Šiauliai City. The Factory was subordinate to the Lithuanian SSR Forest Industry Headquarters. Šiauliai Furniture Factory “Rūdė” was liquidated on 10 February 1949 subject to an Order of the Ministry of Lithuanian Forest and Paper Industry and was incorporated in Šiauliai Wood Processing Factory. The Factory was reorganized into Šiauliai Furniture Association “Venta” on 8 January 1974 following Order of Ministry of Furniture and Wood Processing Industry of Lithuanian SSR.
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Jonsson, Christian. "Detection of annual rings in wood." Thesis, Linköping University, Department of Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-15804.
Повний текст джерелаАнотація:
This report describes an annual line detection algorithm for the WoodEye quality control system. The goal with the algorithm is to find the positions of annual lines on the four surfaces of a board. The purpose is to use this result to find the inner annual ring structure of the board. The work was done using image processing techniques to analyze images collected with WoodEye. The report gives the reader an insight in the requirements of quality control systems in the woodworking industry and the benefits of automated quality control versus manual inspection. The appearance and formation of annual lines are explained on a detailed level to provide insight on how the problem should be approached. A comparison between annual rings and fingerprints are made to see if ideas from this area of pattern recognition can be adapted to annual line detection. This comparison together with a study of existing methods led to the implementation of a fingerprint enhancement method. This method became a central part of the annual line detection algorithm. The annual line detection algorithm consists of two main steps; enhancing the edges of the annual rings, and tracking along the edges to form lines. Different solutions for components of the algorithm were tested to compare performance. The final algorithm was tested with different input images to find if the annual line detection algorithm works best with images from a grayscale or an RGB camera.
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Penniall, Christopher Leigh. "Fischer-Tropsch Based Biomass to Liquid Fuel Plants in the New Zealand Wood Processing Industry Based on Microchannel Reactor Technology." Thesis, University of Canterbury. Chemical and Process Engineering, 2013. http://hdl.handle.net/10092/7884.
Повний текст джерелаАнотація:
This research forms part of a programme of work at the University of Canterbury investigating the production of liquid fuels from biomass. The drivers for this research are the plentiful supply of woody biomass in New Zealand as well as the necessity for a reduction in the use of fossil fuels.
Fischer-Tropsch synthesis has been chosen as the base conversion method for syngas to liquid fuels. While Fischer-Tropsch plants are traditionally very large, the low geographical density of the biomass feedstock necessitates a shift from a traditional economies of scale approach. In this research a sawmill integrated polygeneration scenario is proposed that recognises the synergy between the heat and electrical requirements of a mill and the Fischer-Tropsch process that can supply both as well as liquid fuels. Techno-economic modelling of variations to this polygeneration arrangement were performed using a traditional Fischer-Tropsch slurry reactor as the basis. The breakeven price of syncrude produced in the process based on a 30 year plant life and 10% discount factor was as low as $US 167 per barrel.
This arrangement is coupled with development of and experimentation with a microchannel reactor in a further attempt to overcome economies of scale disadvantages. The lab scale microchannel reactor consisted of a shim with 50 channels of 37mm length with 0.2mm height and 0.3mm width. The microchannel reactor was tested with shorter run periods to compare different catalyst washcoats consisting of neat cobalt, cobalt on titania and a combustion synthesis method over a temperature range of 210-240°C at 20 bar. Comparison was also made to a lab scale fixed bed reactor with a powdered cobalt on titania catalyst. The neat cobalt washcoat proved to have the best performance per unit mass of catalyst of the three washcoats. The performance of the microchannel reactor was 32-40 times better per unit catalyst mass than the fixed bed reactor.
From data based on the shorter runs the neat cobalt washcoat and the cobalt on titania washcoat were selected for further analysis over longer runs at a range of pressures from 2-20 bar and temperatures from 210-240°C. These runs were each approximately 70 hours long and provided a better analysis of the narrowed catalyst choice. The productivity results of the catalysts were fitted to established kinetic equations from literature with an excellent correlation. More accurate Anderson-Schultz-Flory selectivity values were also obtained ranging between 0.72 to 0.82. This is certainly an area that would warrant further attention as a higher selectivity has a very positive affect on plant economics.
Establishment of the kinetic equations for the catalyst performance allowed modelling of reactors with greater volume along with investigation of mass transfer limitations to assist in scale up of the technology. It was found that under 4-5mm hydraulic diameter channel dimensions the mass transfer limitation from the bulk gas phase to the catalyst interface is negligible.
A scaled up microchannel reactor concept design is proposed utilising stainless steel mesh folded into 2mm channels to increase catalyst surface area compared to straight shim. A costing correlation was produced per unit of reactor volume to allow a full scale cost of the microchannel reactor to be estimated for inclusion into the techno-economic model. The revised techno-economic model was optimised through pressure variation to give a breakeven syncrude value of $US118 per barrel at Fischer-Tropsch reaction conditions of 10 bar and 240°C. This brings the value well within historical crude price trends.
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Rall, Ricardo [UNESP]. "Processamento de imagens digitais para detecção e quantificação de defeitos na madeira serrada de coníferas de reflorestamento de uso não estrutural." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/101882.
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rall_r_dr_botfca.pdf: 3009719 bytes, checksum: 38cc6cd9bb7ba17898d531cc167e3715 (MD5)No Brasil, a utilização de Pinus (de reflorestamentos) na indústria madeireira tem sido crescente nos últimos anos. Particularmente para a madeira serrada desse gênero, a produção nacional de madeira serrada de Pinus atingiu 9,46 milhões de m³ em 2008. O crescimento da produção no período de 1999 a 2008 foi de 40,6%. A produção de madeira em ciclos mais curtos tem tornado comum o decréscimo constante na oferta de árvores adultas com grandes diâmetros. Além do aspecto da juvenilidade, nota-se que a madeira hoje disponível para uso industrial e comercial apresenta uma incidência muito grande de nós e outros defeitos, que comprometem significativamente seu desempenho físico mecânico e sua qualidade. Diante dos números que apontam uma crescente demanda por produtos de madeira serrada de Pinus, é natural que a indústria busque formas mais eficientes de garantir a qualidade dos produtos por ela gerados; neste sentido a atividade de inspeção assume um papel importante no processo produtivo. De fato, a classificação de madeira serrada é afetada sensivelmente pela qualidade do trabalho desempenhado pelos graduadores humanos (trabalhadores das serrarias), pois essa é uma atividade estressante, exigindo grande atenção por longos períodos de tempo. O objetivo geral foi o desenvolvimento de técnicas de processamento de imagens digitais para detecção de defeitos na madeira serrada de coníferas. Os objetivos específicos foram, por meio da análise digital das imagens, analisar quais os parâmetros devem ser empregados para a detecção de defeitos na madeira serrada de coníferas, além de desenvolver um software de visão de máquina para a detecção de defeitos na madeira serrada de coníferas. O material utilizado para o estudo foi a madeira extraída de seis árvores de Pinus taeda com 37 anos de idade, provenientes do Horto Florestal de Manduri – SP. As árvores...
In Brazil, the use of Pinus (reforestation) in the timber industry has been growing in recent years. Estimates indicate that the volume of lumber produced in the country, estimated at about 22 million m3, more than 35% is made of pinewood. Timber production in shorter cycles has become common for the steady decline in the supply of mature trees with large diameters (ABRAF, 2009). In the aspect of juvenility, it is noted that the wood available today for industrial and commercial use has a very high number of knots and other defects that significantly impair their physical performance and mechanical quality. Given the numbers that indicate a growing demand for sawn timber products from pine, it is natural that the industry seek more efficient ways to ensure the quality of products generated by it, meaning that the inspection activity plays an important role in the production process. In fact, the classification of lumber is affected significantly by the quality of work performed by human graders (sawmill workers), because this is a stressful activity, requiring close attention for long periods of time. So, the aim of this study was to develop techniques of digital imaging to detect defects in lumber conifers. The specific objectives were, through the analysis of digital images, analyze which parameters should be taken to detect defects in lumber conifers, and develop a software for machine vision detection of defects in lumber conifers. The material used for the study was the wood from six trees of Pinus taeda with 37 years of age, from the forest nursery of Manduri - SP. The trees were split into planks, which led to 84 samples in which they were originally analyzed manually nodes, presence of bone marrow and 17 other conditions that compromise their quality in accordance with standards established by the NBR 12297 (ABNT, 1991). In the processing of digital images acquired from these boards...(Complete abstract click electronic access below)
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Teuber, Laura [Verfasser], Holger [Akademischer Betreuer] [Gutachter] Militz, and Andreas [Gutachter] Krause. "Evaluation of particle and fibre degradation during processing of wood plastic composites (WPC) using dynamic image analysis / Laura Teuber. Betreuer: Holger Militz. Gutachter: Holger Militz ; Andreas Krause." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/1111883483/34.
Повний текст джерела
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Teuber, Laura Verfasser], Holger [Akademischer Betreuer] [Militz, and Andreas [Gutachter] Krause. "Evaluation of particle and fibre degradation during processing of wood plastic composites (WPC) using dynamic image analysis / Laura Teuber. Betreuer: Holger Militz. Gutachter: Holger Militz ; Andreas Krause." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://nbn-resolving.de/urn:nbn:de:gbv:7-11858/00-1735-0000-0028-87FD-D-2.
Повний текст джерела
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Ignatavičius, Edgaras. "Elektros energijos naudojimo tyrimas medienos apdirbimo pramonėje." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080929_125503-72757.
Повний текст джерелаАнотація:
Didžiulės elektros energijos vartojimo sąnaudos karkasinių namų gamyboje ganėtinai ženkliai didina gamybos savikainos kaštus, kas tiesiogiai atsiliepia įmonės pelnui. Medienos apdorojimo pramonės produkcijos galima pagaminti gerokai daugiau (arba pagaminant tą patį kiekį suvartoti mažiau elektros energijos), ne vien tik kuriant naujus didesnio našumo medienos apdirbimo įrenginius, bet ir racionaliai naudojant esamus, bei nuolat juos modernizuojant. Šiame darbe tiriamas karkasinius namus gaminančios ir statančios įmonės UAB „Namų statyba“ elektros energijos suvartojimas. Buvo siekiama nustatyti elektros energijos taupymo galimybes, iš įmonės elektros energijos suvartojimo pereiti prie energijos sunaudojimo normos vienam karkasiniam namui pagaminti. Atlikus tyrimą nustatyta, kurioje medienos apdirbimo operacijoje galima būtų sumažinti elektros energijos suvartojimą. Taip pat pateikiami pagrįsti elektros energijos efektyvumo didinimo būdai.Engineering prime costs increase because of a great consumption input of electricity energy at framework house manufacture, which directly influence company profit. It is possible to produce much more wood processing industry output (or to consume less electricity energy while producing the same quantity), not only by creating new mechanisms of greater wood processing productivity, but also by racionally using the present ones and constantly modernizing them. The consume of electricity energy of the JSC „Namų statyba“ which specializes at manufacturing and building framework houses is being researched at this work. The target was to estimate the saving potencial of electricity energy and to come from company electricity energy consume to the norm of electricity energy that is necessary to build a single framework house. Wood processing operation at which it is possible to reduce electricity energy consumtion was estimated after the research. The reasoned methods how to increase the effectiveness of electricity energy are presented as well.
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Scapinello, Marco. "Studio di processi al plasma freddo a pressione atmosferica per il trattamento delle fibre tessili." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422496.
Повний текст джерелаАнотація:
The main goals of my thesis project were to study, characterize and optimize the interaction of different atmospheric plasmas with textile materials (wool and cotton), to determine the effects of such interactions on the treated materials and to correlate them with the specific experimental conditions used. This thesis deals with the application of non-thermal plasmas to textile fibers and materials to achieve desired effects and properties such as anti-shrinking, anti-felting, wetting and the activation for wet finishing.
The analysis of the plasma processed gas was performed by FT-IR and APCI mass spectrometry. The results of this characterization allow us to understand the chemical oxidation phenomena.
The plasma treatment on wool fibers produces wettability and anti-shrinking properties, this effects are due to the oxidation and to the roughness imparted to the treatment.
The plasma treatment on the cotton fibers increases the hydrophilicity for the formation of new polar species and radicals on the surface: two wet finishing were applied to test the effects of plasma pre-treatment.
Finally, using OES we succeeded in characterizing a few important systems related to the gas composition and the radiative active specie of plasma (including radicals, ions, atoms or excited molecules).
In conclusion, the results of the research carried out for my doctoral thesis show that non-thermal plasma holds great promise for the treatment of fabrics: it offers the advantage of doing away with costly and environmentally impacting wet processes while at the same time producing similar or even better results in the treated materials.Il mio progetto di tesi ha riguardato lo studio, la caratterizzazione e l’ottimizzazione delle interazioni di diversi plasmi atmosferici con il materiale tessile (in particolare lana e cotone), determinando gli effetti che tale interazione produce sul materiale trattato e correlandola alle specifiche condizioni utilizzate. Lo scopo fortemente applicativo era quello di ottenere particolari proprietà ed effetti come l’antirestringimento, la bagnabilità, l’attivazione per successivi finissaggi liquidi. La caratterizzazione del gas di processo mediante spettroscopia FTIR e spettrometria di massa APCI ha permesso di comprendere la chimica dei fenomeni di ossidazione alla base degli effetti del trattamento. Il trattamento sulla fibra di lana produce una forte bagnabilità ed effetti di anti-restringimento, correlabili all'ossidazione della superficie e all'aumentata rugosità. Il trattamento sulla fibra di cotone aumenta l'idrofilicità della fibra per la formazione di radicali e nuove specie polari sulla superficie: sono stati applicati due finissaggi liquidi per verificare gli effetti del pretrattamento al plasma. Infine utilizzando di una tecnica diagnostica come la spettroscopia ottica di emissione è stato possibile caratterizzare alcuni importanti sistemi di emissione dovuti alla presenza di specie eccitate di atomi, molecole, radicali e ioni presenti in un plasma atmosferico. I risultati della ricerca effettuata per il dottorato dimostrano che il plasma atmosferico non termico rappresenta una grande promessa per il trattamento dei tessuti: offre il vantaggio di sostituire o di migliorare i processi liquidi costosi e di forte impatto ambientale e al tempo stesso di ottenere risultati simili o anche migliori nei materiali trattati.
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Karinkanta, P. (Pasi). "Dry fine grinding of Norway spruce (Picea abies) wood in impact-based fine grinding mills." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526207193.
Повний текст джерелаАнотація:
Abstract Wood powders are used in numerous applications such as thermoplastics and filters, and a lot of research effort has been put into developing novel ways of utilising them. The mechanical processing of wood powders, especially at particle sizes below 100 µm, has been reported in several studies, but they lack information on the effect of fine grinding conditions on the particle morphology and cellulose crystallinity, both of which are important parameters in the further processing of wood powders and in their various applications. This makes it very difficult to design and optimise fine grinding processes with different applications in mind. The aim of this thesis was to study the dry fine grinding of wood in several impact-based fine grinding mills in order to find out their effect on the properties of the wood and to study the energy required for the mechanical processing of the resulting powders. The effect of the main operational parameters on the properties of dried Norway spruce wood and the energy consumption was studied using three impact-based fine grinding mills that were capable of pulverising the wood down to a median particle size of less than 25 µm. It was found that the impact events occurring in media mills can be used for the production of very fine wood powders with lower cellulose crystallinity and rounder shaped particles having more uniform shape distribution than powders pulverised to a similar size range by means of impact events in non-media mills. A practical estimate was obtained for the minimum specific energy consumption in fine grinding in mills involving grinding media that could be utilised as a target for optimisation. Impact-based media milling under cryogenic conditions can be used to obtain different Norway spruce wood powders from those produced under ambient grinding conditions, i.e. without the freezing effect of nitrogen liquid. The energy efficiency of fine grinding can be enhanced by choosing cryogenic rather than ambient conditions. The moisture content of the wood has greater influence on the size and shape of the particles when milling is accomplished under ambient conditions. Torrefaction can reduce the energy consumption in impact-based media mills for median particle sizes over 17.4 µm (± 0.2 µm), while the shape and cellulose crystallinity of the particles are not significantly affected by torrefaction pretreatment as a function of energy consumptionTiivistelmä Puujauheita käytetään laajalti erilaisissa sovelluksissa, kuten esimerkiksi biokomposiiteissa ja suodattimissa. Tämän lisäksi on olemassa paljon tutkimustietoa siitä, kuinka puujauheita voitaisiin hyödyntää laajemminkin. Puu voidaan mekaanisesti prosessoida alle 100 µm:n kokoluokkaan, mutta yksityiskohtaista tietoa kuivahienojauhatuksen olosuhteiden vaikutuksesta jauheiden morfologiaan ja selluloosan kiteisyyteen ei ole saatavilla. Puujauheen morfologialla ja selluloosan kiteisyydellä on kuitenkin merkittävä vaikutus sovelluksia ja jatkojalostusta ajatellen. Puun kuivahienojauhatuksen tiedon puute hankaloittaa merkittävästi prosessin suunnittelua ja optimointia erilaisia sovelluksia varten. Tämän väitöskirjan tavoitteena on selvittää iskuihin perustuvien hienojauhimien vaikutukset puun ominaisuuksiin ja tutkia mekaanisen prosessoinnin energiatehokkuutta hienojauhatuksessa. Tutkimuksessa selvitettiin kolmen erilaisen iskuun perustuvan hienojauhatusmyllyn pääasiallisten operointiparametrien vaikutusta kuivatun metsäkuusen ominaisuuksiin ja energiankulutukseen. Jokaisella hienojauhimella onnistuttiin tuottamaan puujauhoja, joiden mediaanikoko oli alle 25 µm. Iskuihin perustuvalla jauhinkappalemyllyllä saatiin tuotettua puujauhoa, jonka selluloosan kiteisyys on alhaisempi ja partikkelimuodot pyöreämpiä verrattuna samankokoisiin puujauhoihin, jotka on tuotettu iskuihin perustuvilla jauhinkappaleettomilla hienojauhatusmyllyillä. Työssä saatiin käytännöllinen arvio kuivatun metsäkuusen hienojauhatuksen minimienergiankulutukselle iskuihin perustuville jauhinkappalemyllyille, mitä voidaan käyttää kyseisten myllytyyppien optimoinnin tavoitteena. Työssä havaittiin lisäksi, että kryogeenisiä jauhatusolosuhteita käyttämällä voidaan tuottaa erilaisia puujauhoja verrattuna puujauhoihin, jotka prosessoidaan ilman nestetyppijäädytystä, kun jauhatus suoritetaan iskuihin perustuvalla jauhinkappalemyllyllä. Ilman nestetyppijäädytystä puun kosteuspitoisuudella on merkittävämpi vaikutus puujauhojen ominaisuuksiin kuin kryogeenisissä olosuhteissa jauhetuilla. Kryogeenisillä jauhatusolosuhteilla voidaan parantaa myös jauhatuksen energiatehokkuutta. Torrefioinnilla voidaan vähentää hienojauhatuksen energiankulutusta iskuihin perustuvilla jauhinkappalemyllyillä, kun tavoitekoon mediaani on yli 17,4 µm (± 0,2 µm). Torrefioinnilla ei ole vaikutusta selluloosan kiteisyyteen tai partikkeleiden muotoon energiankulutuksen funktiona
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Ennigkeit, Fabienne [Verfasser], Frank [Akademischer Betreuer] Hänsel, Frank [Gutachter] Hänsel, Christopher [Gutachter] Heim, and Alexander [Gutachter] Woll. "The moderating role of exercise self-schema and exercise identity on the processing of self-relevant feedback / Fabienne Ennigkeit ; Gutachter: Frank Hänsel, Christopher Heim, Alexander Woll ; Betreuer: Frank Hänsel." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2018. http://d-nb.info/1164077333/34.
Повний текст джерела
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Davenport, George Andrew 1965. "A process control system for biomass liquefaction." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/558114.
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Johnson, Robert A. "A Comparison Between Two-Dimensional and Three-DimensionalAnalysis, A Review of Horizontal Wood Diaphragms and a Case Study of the Structure Located at 89 Shrewsbury Street, Worcester, MA." Digital WPI, 2008. https://digitalcommons.wpi.edu/etd-theses/524.
Повний текст джерелаАнотація:
A two-dimensional structural analysis design approach has been the universally accepted method for a small structural engineering design firm. The tools to perform the analysis have been paper and pencil, calculators and more recently personal computers with two-dimensional software. With the introduction of three-dimensional software, a major shift is occurring on how small structural engineering firms approach analysis and design. This thesis research reviews the analysis of an existing building utilizing the standard two-dimensional approach, including horizontal diaphragm-action within wood floors. This study also reviews the research performed on horizontal diaphragms and investigates the use of three-dimensional, finite element modeling (RISA-3D) for the analysis of horizontal diaphragms. It is shown that the three-dimensional model can provide results similar to the two-dimensional hand calculations. However, the thickness of the diaphragm elements has to be significantly modified for flexible diaphragm action. The experience described herein is useful for structural engineer interfacing within three-dimensional CAD systems. The thesis concludes with a discussion on the challenges facing small structural engineering firms, including computer based technologies, engineering expertise to develop contract documents and review shop drawings, and outsourcing of design services.
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Possamai, Daniel Giovani. "Análise numérica do escoamento turbulento no interior de secadores." Universidade do Estado de Santa Catarina, 2013. http://tede.udesc.br/handle/handle/2057.
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The main objective of the present work is the numerical simulation of an incompressible, isothermal turbulent flow inside a timber dry kiln using the commercial software ANSYS CFX®. The physical study aims at assessing the dry kiln aerodynamics by determining the velocity distribution inside the kiln for different operating conditions. In the study of the flow topology inside the dry kiln, the analysis is focused mainly on the evaluation of the influence of the (i) width of the inlet plenum and (ii) flow velocity at its entrance. The simulations show that the plenum width has a direct influence on the velocity distribution in the kiln. This parameter directly affects the location and size of the vortex generated just after the plenum entrance corner. Moreover, the variation of the inlet velocity imposes no significant differences in the flow topology inside the kiln. Finally, it is worth to emphasize that to significantly improve flow uniformity in the channels across the stack height it is necessary to find alternatives able to reduce or eliminate the vortex generated at the entrance of the inlet plenum .
O presente trabalho teve por objetivo principal a análise de um escoamento turbulento incompressível e isotérmico no interior de um secador de madeira utilizando uma metodologia numérica baseada no programa comercial ANSYS CFX®. O estudo físico realizado consistiu em avaliar a aerodinâmica do secador, a saber: determinar a distribuição de velocidades no interior do dispositivo em diferentes condições de operação. No estudo da topologia do escoamento no interior do secador de madeira, a análise foi focada, principalmente, na avaliação da influência dos seguintes parâmetros: (i) largura do canal vertical de entrada, plenum e (ii) velocidade do escoamento na entrada. De acordo com os resultados obtidos, a largura do plenum tem influência direta na distribuição de velocidades no interior do secador. Este parâmetro está diretamente relacionado à localização e tamanho do vórtice gerado após a quina de entrada. Por outro lado, a variação da velocidade de entrada não apresentou diferenças significativas na topologia do escoamento no interior do secador. Por fim, vale salientar que para se obter ganhos significativos na uniformidade do escoamento nos canais faz-se necessário encontrar alternativas que minimizem o vórtice gerado na quina de entrada do secador.
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Rall, Ricardo 1968. "Processamento de imagens digitais para detecção e quantificação de defeitos na madeira serrada de coníferas de reflorestamento de uso não estrutural /." Botucatu : [s.n.], 2010. http://hdl.handle.net/11449/101882.
Повний текст джерелаАнотація:
Resumo: No Brasil, a utilização de Pinus (de reflorestamentos) na indústria madeireira tem sido crescente nos últimos anos. Particularmente para a madeira serrada desse gênero, a produção nacional de madeira serrada de Pinus atingiu 9,46 milhões de m³ em 2008. O crescimento da produção no período de 1999 a 2008 foi de 40,6%. A produção de madeira em ciclos mais curtos tem tornado comum o decréscimo constante na oferta de árvores adultas com grandes diâmetros. Além do aspecto da juvenilidade, nota-se que a madeira hoje disponível para uso industrial e comercial apresenta uma incidência muito grande de nós e outros defeitos, que comprometem significativamente seu desempenho físico mecânico e sua qualidade. Diante dos números que apontam uma crescente demanda por produtos de madeira serrada de Pinus, é natural que a indústria busque formas mais eficientes de garantir a qualidade dos produtos por ela gerados; neste sentido a atividade de inspeção assume um papel importante no processo produtivo. De fato, a classificação de madeira serrada é afetada sensivelmente pela qualidade do trabalho desempenhado pelos graduadores humanos (trabalhadores das serrarias), pois essa é uma atividade estressante, exigindo grande atenção por longos períodos de tempo. O objetivo geral foi o desenvolvimento de técnicas de processamento de imagens digitais para detecção de defeitos na madeira serrada de coníferas. Os objetivos específicos foram, por meio da análise digital das imagens, analisar quais os parâmetros devem ser empregados para a detecção de defeitos na madeira serrada de coníferas, além de desenvolver um software de visão de máquina para a detecção de defeitos na madeira serrada de coníferas. O material utilizado para o estudo foi a madeira extraída de seis árvores de Pinus taeda com 37 anos de idade, provenientes do Horto Florestal de Manduri - SP. As árvores... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: In Brazil, the use of Pinus (reforestation) in the timber industry has been growing in recent years. Estimates indicate that the volume of lumber produced in the country, estimated at about 22 million m3, more than 35% is made of pinewood. Timber production in shorter cycles has become common for the steady decline in the supply of mature trees with large diameters (ABRAF, 2009). In the aspect of juvenility, it is noted that the wood available today for industrial and commercial use has a very high number of knots and other defects that significantly impair their physical performance and mechanical quality. Given the numbers that indicate a growing demand for sawn timber products from pine, it is natural that the industry seek more efficient ways to ensure the quality of products generated by it, meaning that the inspection activity plays an important role in the production process. In fact, the classification of lumber is affected significantly by the quality of work performed by human graders (sawmill workers), because this is a stressful activity, requiring close attention for long periods of time. So, the aim of this study was to develop techniques of digital imaging to detect defects in lumber conifers. The specific objectives were, through the analysis of digital images, analyze which parameters should be taken to detect defects in lumber conifers, and develop a software for machine vision detection of defects in lumber conifers. The material used for the study was the wood from six trees of Pinus taeda with 37 years of age, from the forest nursery of Manduri - SP. The trees were split into planks, which led to 84 samples in which they were originally analyzed manually nodes, presence of bone marrow and 17 other conditions that compromise their quality in accordance with standards established by the NBR 12297 (ABNT, 1991). In the processing of digital images acquired from these boards...(Complete abstract click electronic access below)
Orientador: Adriano Wagner Ballarin
Coorientador: Antônio César Germano Martins
Banca: José Martins de Oliveira Junior
Banca: AntonioAlves Dias
Banca: Jayme Laperuta Filho
Banca: Hernando Alfonso Lara Palma
Doutor
50
Lojda, Martin. "Ekonomická studie využití mobilní pásové pily v podmínkách ČR." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228887.
Повний текст джерелаАнотація:
The thesis deals with possibilities of using of mobile band saws. An economic analysis of band saw utilization for woodworking was carried out. Further the work evaluates and analyses the technological string of lumber production in a selected area. In the first part there is a study of current state of technological string of saw timber production. The second chapter deals with the evaluation of state in consideration of woodworking in relation to selected location of production facilities. The third part is focused on evaluation of possibilities of mobile band saw utilization that is carried out on Husqvarna SMB - 70. The fourth section describes technological variations and tries to determine criteria for choosing of the best variant. It details opportunities of a small - grower that tries to find the most suitable variant by selling a wood, so as it brings the maximum profit. The work deals with various possibilities of timber production in which the band saw is included. Technical parameters of particular saws are described here. And by means of economic parameters the most suitable technology for sawn wood production is determined. The goal of this thesis is to choose a suitable technology for timber production based on economic analysis and with regard to conditions of the processing plant.