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1
Lalicata, Leonardo Maria, Agostino Walter Bruno e Domenico Gallipoli. "Hygro-thermal coupling in earth building materials". E3S Web of Conferences 382 (2023): 23003. http://dx.doi.org/10.1051/e3sconf/202338223003.
Testo completoAbstract (sommario):
Raw earth is emerging as a viable building material with lower carbon emissions than conventional concrete and fired bricks. Raw earth is as an excellent passive hygro-thermal regulator, which improves occupants’ comfort while reducing the need for active heating/cooling installations. The coupled hygro-thermal response of earth materials is investigated by exploiting the principles of the thermodynamics of porous media and unsaturated soil mechanics. The degree of coupling between temperature and relative humidity (or water content) depends on the adopted simplifying assumptions. Some of these assumptions are valid for traditional building materials but may not be applicable to raw earth characterised by relatively high levels of liquid/gas permeability. The validity of current approaches is here assessed with reference to earth building via a simple one-dimensional transfer model, which simulates the behaviour of an unbounded earth wall subjected to time-dependent boundary conditions on the two faces. For typical values of water and vapour permeability, the complexity of the governing equations can be greatly reduced by neglecting variations of vapour mass and the dependency of suction on temperature without significantly reducing accuracy. Results are also strongly influenced by both initial state and water retention properties of the earth material.
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MEDEIROS, CARLOS AGUIAR DE, e NICHOLAS M. TREBAT. "Transforming natural resources into industrial advantage: the case of China’s rare earths industry". Brazilian Journal of Political Economy 37, n. 3 (luglio 2017): 504–26. http://dx.doi.org/10.1590/0101-31572017v37n03a03.
Testo completoAbstract (sommario):
ABSTRACT This paper analyzes the development of China’s rare earths industry, emphasizing the role of state technological initiatives in the country’s transition from rare earth exporter to large industrial consumer of these raw materials. Like other industrial powers before it, China takes advantage of low-cost domestic supplies of strategic raw materials to promote higher value-added manufacturing. We argue that, in the case of rare earths, this strategy has been largely successful, disrupting a classic international division of labor that existed prior to 2000, in which China exported most of its rare earth output to wealthy countries, and transforming Chinese firms into exporters of more sophisticated downstream products.
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Ewing, Rodney C., e Alexandra Navrotsky. "Earth Materials". MRS Bulletin 17, n. 5 (maggio 1992): 19–22. http://dx.doi.org/10.1557/s0883769400041233.
Testo completoAbstract (sommario):
This issue of the MRS Bulletin is devoted to Earth materials — a subject so broad and with such a long history, stretching back to man's first use of materials, that we can offer only a small sample of topics, only a partial review. As our ancestors fashioned the first crude tools from stone, they must have distinguished among materials on the basis of their physical properties. They classified materials by color and density and very early must have wanted more than Nature had provided. They began to synthesize and fashion their own materials. Today's nanoscale engineering of materials is part of this same quest—a continuous evolution of this early toolmaking.Thus, Earth materials were the first raw materials—and the first subjects of study and classification in materials science. Probably one of the earliest materials scientists to make quantitative observations was Nicolas Steno (1638–1686, actually Nils Stensen, a Dane by birth), who was among the first to note the “law of constancy of angle” in comments which accompany his drawings of quartz and hematite crystals (De Solido intra Solidum Naturaliter Conteno Dissertationis Prodromus, 1669). Such observations were the first clues to understanding the internal structure of solids. Steno was also a keen geological observer. He is given credit for the first statement of the law of superposition of sedimentary strata. The first quantitative experiments on the origin of minerals grew out of studies of glass and ceramics. French mathematician René-Antoine Ferchault de Réaumur (1683–1757) tried to determine the composition of Chinese porcelain by melting minerals and rocks.
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Giada, Giuffrida, Rosa Caponetto e Francesco Nocera. "Hygrothermal Properties of Raw Earth Materials: A Literature Review". Sustainability 11, n. 19 (27 settembre 2019): 5342. http://dx.doi.org/10.3390/su11195342.
Testo completoAbstract (sommario):
Raw earth historic and contemporary architectures are renowned for their good environmental properties of recyclability and low embodied energy along the production process. Earth massive walls are universally known to be able to regulate indoor thermal and hygroscopic conditions containing energy consumptions, creating comfortable interior spaces with a low carbon footprint. Therefore, earth buildings are de facto green buildings. As a result of this, some earthen technologies have been rediscovered and implemented to be adapted to the contemporary building production sector. Nevertheless, the diffusion of contemporary earthen architecture is decelerated by the lack of broadly accepted standards on its anti-seismic and thermal performance. Indeed, the former issue has been solved using high-tensile materials inside the walls or surface reinforcements on their sides to improve their flexural strength. The latter issue is related to the penalization of earth walls thermal behavior in current regulations, which tent to evaluate only the steady-state performance of building components, neglecting the benefit of heat storage and hygrothermal buffering effect provided by massive and porous envelopes as raw earth ones. In this paper, we show the results of a paper review concerning the hygrothermal performance of earthen materials for contemporary housing: great attention is given to the base materials which are used (inorganic soils, natural fibers, and mineral or recycled aggregates, chemical stabilizers), manufacturing procedures (when described), performed tests and final performances. Different earth techniques (adobe, cob, extruded bricks, rammed earth, compressed earth blocks, light earth) have been considered in order to highlight that earth material can act both as a conductive and insulating meterial depending on how it is implemented, adapting to several climate contests. The paper aims to summarize current progress in the improvement of thermal performance of raw earth traditional mixes, discuss the suitability of existing measurement protocols for hygroscopic and natural materials and provide guidance for further researches.
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Leal Filho, Walter Leal, Richard Kotter, Pinar Gökçin Özuyar, Ismaila Rimi Abubakar, João Henrique Paulino Pires Eustachio e Newton R. Matandirotya. "Understanding Rare Earth Elements as Critical Raw Materials". Sustainability 15, n. 3 (19 gennaio 2023): 1919. http://dx.doi.org/10.3390/su15031919.
Testo completoAbstract (sommario):
The boom in technological advances in recent decades has led to increased demand for rare earth elements (REEs) (also known as rare earth metals) across various industries with wide-ranging industrial applications, including in the clean energy sector, but with some environmental, economic, and social footprint concerns. This paper reviews the complexities of the production, consumption, and reuse or recovery of REEs, presenting current trends in terms of potentials and challenges associated with this. This paper in particular focuses on the supply, demand, and (environmental and economic) sustainability of REEs, as a subset of critical raw materials. It does so via a critical stocktaking of key discussions and debates in the field over the past 15 years up until now, through a thematic analysis of the published and gray (policy) literature with a grounded theory approach. The paper finds that carefully balanced lifecycle sustainability assessments are needed for assessing the respective dimensions of the extraction, processing, and reuse or recovery methods for different types of REE sources and supplies to meet current and future demands. It furthermore diagnoses the need for taking into account some shifts and substitutions among REEs also for reasons of cost and locational supplies for the security of supply. Finally, the paper provides some overall policy recommendations for addressing current problems, with a conceptual framing of the UN Sustainable Development Goals.
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H. Khalid, Ameer, e Thanoon A. Thanoon. "Study of Silica Occurrence in the Raw Materials of HammamAl- Alil Cement Plant". Iraqi National Journal of Earth Sciences 10, n. 1 (28 giugno 2010): 33–46. http://dx.doi.org/10.33899/earth.2010.5556.
Testo completo
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Kamprowski, Rafał. "The raw materials policy of the European Union for rare earth elements". Rocznik Integracji Europejskiej, n. 16 (22 febbraio 2023): 243–50. http://dx.doi.org/10.14746/rie.2022.16.14.
Testo completoAbstract (sommario):
This article deals with one of the dimensions of the European Union’s raw materials policy, including rare earth elements (REE). The core and overarching goal of the raw materials policy implemented by a given entity is to ensure security in terms of raw materials. Taking into account the current geopolitical situation and the ongoing war in Ukraine, the main part of discussion regarding raw materials security focuses on issues related to the supply of energy sources, including gas or coal. Rare earth elements, however, remain on the side-lines of these considerations. Rare earth elements are the foundation of modern technological development in many areas and fields. Due to their role, they have been the object of political rivalry between the People’s Republic of China and the United States of America for at least twenty years. The question of the place and role of the European Union in this system remains open. The research intention of the considerations in this article is to indicate the role of REEs in the raw materials policy implemented by the European Union. The research shows that, despite the relatively late involvement of the European Union in the identification of key REEs and the development of their supply chain, a clear professionalisation of EU practices has been observed for several years. It is also indicated that among the most important challenges for the European Union’s raw materials policy are factors such as excessive dependence of the supply chain on the People’s Republic of China and difficulties in obtaining REEs within the territory of European Union member states.
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Wang, Yun. "Study on Modification of Rammed Earth Material in Mountain Areas". Advanced Materials Research 261-263 (maggio 2011): 1178–81. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1178.
Testo completoAbstract (sommario):
In order to explore the proper modified materials of the raw-soil building in mountain area, the raw-soil modified materials now being used commonly are analyzed effectively at first, and the natural reborn starch resource is thought which has a promising application prospect. In the end, experiments on compressive properties and shear properties of raw-soil material modified by quicklime, slaked lime and starch with different incorporation rates are carried out, and the tests show starch is applicable to modify raw-soil in mountain area.
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Fabbri, Antonin, Jean-Claude Morel e Domenico Gallipoli. "Assessing the performance of earth building materials: a review of recent developments". RILEM Technical Letters 3 (22 dicembre 2018): 46–58. http://dx.doi.org/10.21809/rilemtechlett.2018.71.
Testo completoAbstract (sommario):
After being almost abandoned at the end of the Second World War, the use of raw earth is currently regaining the interest of architects, engineers and policy makers for the construction of dwellings in industrialised countries. This renaissance is driven by growing ecological awareness and the promotion of construction techniques that minimize energy consumption and carbon emissions. Raw earth displays very interesting thermo-hygro-mechanical properties, which can contribute to the reduction of the environmental impact of buildings not only during construction but also during service life. Nevertheless, one of the reasons that still prevents dissemination of raw earth into construction practice is the lack of commonly agreed procedures for assessing material performance. The RILEM technical committee TCE 274 has been established as a first step for overcoming this obstacle. The objective of the technical committee is to critically examine current testing procedures in order to propose suitable experimental standards. The results of this work will be presented in future publications while the present paper summarizes the main challenges faced by the committee and briefly describes some of the existing procedures for measuring the engineering properties of earth materials.
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Lu, Bai-ru, Kun Zhang e Zhan Qu. "Research on Compressive Tests of Iron Tailing and Cement-Modified Earth Materials from Northwest China". Advances in Civil Engineering 2023 (21 ottobre 2023): 1–12. http://dx.doi.org/10.1155/2023/6661545.
Testo completoAbstract (sommario):
The strength of earth-modified materials is an important mechanical indicator of raw soil building materials. Iron tailings are a rich mineral waste resource with basic properties similar to river sand and can be used as a modified material for raw soil construction. To increase the utilization rate of iron tailings and improve the mechanical properties of earth materials, modification of earth materials were analyzed using iron tailings and cement. Through a single lattice theory design method, 10 different blending ratios of modified earth specimens were designed, with each group comprising six 100 mm cubic specimens. Earth specimens were used as the control group and compression tests carried out under standard curing conditions, with analysis of the failure mode, compressive strength, deformation, and load–displacement curve for each specimen. Also, the reasons for specimen failures were examined, including the influence of strength, dispersion, and implications of load–displacement curves. The optimal mix ratio of modified materials was determined using frequency domain analysis method. The results showed that the load–displacement curves of materials with different material ratios were basically similar and the slope and discreteness of the curves quite different. Increased tailings and cement content improved the compressive strength of earth materials and increased the discreteness of the material. Through frequency analysis, it was obtained that when the content of tailings was 12.1%–19.5%, cement content 13.9%–19.1%, and earth 65.5%–69.9%, there was a 95% of the guaranteed rate of compressive strength of iron tailings and cement-modified earth materials between 6 and 9 MPa. Iron tailings can, thus, be used as the preferred material for modifying earth materials; single lattice theory can be used as the design method for mixing experiments, and frequency domain analysis can be an effective calculation method for optimizing mixing design. Adding cement and iron tailings to modify the raw soil formula can provide reference for the selection of basic materials for raw soil construction.
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Zhang, Yi, Xiaoling Li, Jun Zhu, Danhong Zhou, Ying Li e Chengcheng Liu. "Design, synthesis, and thermal stability of rare earth luminescent materials". Thermal Science 28, n. 2 Part B (2024): 1405–12. http://dx.doi.org/10.2298/tsci2402405z.
Testo completoAbstract (sommario):
As a new generation of luminescent materials, aluminate rare earth materials have the characteristics of long luminescent time, adjustable wavelength and high brightness. Aluminate rare earth luminescent materials were prepared by high temperature solid-state method, and the luminescent properties of the luminescent materials were studied. Firstly, the author synthesized magnesium aluminate, calcium aluminates, and zinc aluminate matrix by combustion method. Then aluminate rare earth luminescent materials were prepared by high temperature solid phase method through raw material distribution, raw material mixing, drying, calcination, and post-treatment. Finally, a fluorescence spectrophotometer was used to measure the excitation and emission spectra of the prepared sample material. The research results indicate that the excitation wavelength does not affect the relationship between the emission wavelength and light intensity, the emission spectra of MgAl2O4:Tb3+ and CaAl2O4:Tb3+ exhibit narrowband transition emission states; When the mass fraction of rare earth factor Eu3+ in the activator is 6% and the temperature is 1300?C, the emission peak intensity of the luminescent material reaches its maximum value, and the luminescence intensity is the best.
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Tourtelot, Julia, Ann Bourgès e Emmanuel Keita. "Influence of Biopolymers on the Mechanical Behavior of Earth-Based Building Materials". Recent Progress in Materials 03, n. 03 (9 marzo 2021): 1. http://dx.doi.org/10.21926/rpm.2103031.
Testo completoAbstract (sommario):
Currently, the largest among the earth excavation sites in Europe are located in the Paris region. The soils excavated from these sites are often considered waste and are not valorized. With an increasing focus on sustainable development, the demand for low-carbon building materials is rising. Although construction using raw earth is a vernacular technique, the diversity in the behavior of the raw earth building materials warrants better control of their mechanical properties. The construction techniques differ depending on the location of the site, the composition of the earth, and the stabilizers used. Plant-based fibers and compounds extracted from plants are commonly used for reinforcing raw earth. Since such byproduct solutions have been developed worldwide, they differ significantly, and it becomes difficult to set a benchmark. The majority of the reported studies have directly used organic waste, rendering it difficult to characterize the material and extend the obtained results to other contexts. In order to reduce these variabilities, it becomes important to study the reinforcement of earth-based building materials with biopolymers that constitute the active molecules of the bio-based solutions. In the present study, different biopolymers derived from various vernacular techniques were utilized to increase the compressive strength of the construction soil collected from the Paris region. It was revealed that cellulose fibers and wheat starch increased the compressive strength of the earth from 3.5 MPa to 5.5 MPa and 4.5 MPa, respectively. In addition, the interactions of these biopolymers with clay were analyzed. The biopolymers identified as suitable for use in construction materials in the present study are widely available as wastes from paper, agricultural, or agro-food industries. These identified biopolymers would contribute to the development and standardization of construction using earth-based building materials.
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Rhodes, Christopher J. "Endangered elements, critical raw materials and conflict minerals". Science Progress 102, n. 4 (4 novembre 2019): 304–50. http://dx.doi.org/10.1177/0036850419884873.
Testo completoAbstract (sommario):
Amid present concerns over a potential scarcity of critical elements and raw materials that are essential for modern technology, including those for low-carbon energy production, a survey of the present situation, and how it may unfold both in the immediate and the longer term, appears warranted. For elements such as indium, current recycling rates are woefully low, and although a far more effective recycling programme is necessary for most materials, it is likely that a full-scale inauguration of a global renewable energy system will require substitution of many scarcer elements by more Earth-abundant material alternatives. Currently, however, it is fossil fuels that are needed to process them, and many putative Earth-abundant material technologies are insufficiently close to the level of commercial viability required to begin to supplant their fossil fuel equivalents “necessarily rapidly and at scale”. As part of a significant expansion of renewable energy production, it will be necessary to recycle elements from wind turbines and solar panels (especially thin-film cells). The interconnected nature of particular materials, for example, cadmium, gallium, germanium, indium and tellurium, all mainly being recovered from the production of zinc, aluminium and copper, and helium from natural gas, means that the availability of such ‘hitchhiker’ elements is a function of the reserve size and production rate of the primary (or ‘attractor’) material. Even for those elements that are relatively abundant on Earth, limitations in their production rates/supply may well be experienced on a timescale of decades, and so a more efficient (reduced) use of them, coupled with effective collection and recycling strategies, should be embarked upon urgently.
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Spiridigliozzi, Luca, Claudio Ferone, Raffaele Cioffi, Mauro Bortolotti e Gianfranco Dell’Agli. "New Insights in the Hydrothermal Synthesis of Rare-Earth Carbonates". Materials 12, n. 13 (27 giugno 2019): 2062. http://dx.doi.org/10.3390/ma12132062.
Testo completoAbstract (sommario):
The rare-earth carbonates represent a class of materials with great research interest owing to their intrinsic properties and because they can be used as template materials for the formation of other rare earth phases, particularly of rare-earth oxides. However, most of the literature is focused on the synthesis and characterization of hydroxycarbonates. Conversely, in the present study we have synthesized both rare-earth carbonates—with the chemical formula RE2(CO3)3·2-3H2O, in which RE represents a generic rare-earth element, and a tengerite-type structure with a peculiar morphology—and rare-earth hydroxycarbonates with the chemical formula RECO3OH, by hydrothermal treatment at low temperature (120 °C), using metal nitrates and ammonium carbonates as raw materials, and without using any additive or template. We found that the nature of the rare-earth used plays a crucial role in relation to the formed phases, as predicted by the contraction law of lanthanides. In particular, the hydrothermal synthesis of rare-earth carbonates with a tengerite-type structure was obtained for the lanthanides from neodymium to erbium. A possible explanation of the different behaviors of lighter and heavier rare-earths is given.
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Zhang, Kun, Bai-Ru Lu, Yi-Hong Wang, Zhan Qu e Le Qu. "Study on the Modification Formula of Earth Material Compound with Cement and Gravel by Single Lattice Theory". Advances in Civil Engineering 2020 (19 dicembre 2020): 1–10. http://dx.doi.org/10.1155/2020/8136570.
Testo completoAbstract (sommario):
Gravel and cement can effectively improve the low strength of traditional Earth materials. There have been few studies on test methods for raw soil-based composite admixtures. By introducing the theory of single lattice formula testing, the compressive strength of 10 formulas and 60 modified raw soil cubic specimens were tested. The failure process, failure mode, and compressive strength of specimens were studied. The effects of different formulations of raw soil on strength, peak displacement, and dispersion were analyzed. The results showed that cement content had a significant effect on the compressive strength and dispersion of earth material specimens. The optimal modification formula of cement, gravel, and raw soil was determined to be 0.1/0.08/0.82 (mass ratio). At the same time, the applicability of the test method was verified, which can be used as a reference for the experimental study on modification formulations of earth materials.
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Kengaliev, B. K., T. YU Surkova, S. B. Yulusov, E. A. Pirmatov e A. P. Dulenin. "Rare-Earth Concentrate Production From Technogenic Mineral Formations". KnE Materials Science 2, n. 2 (3 settembre 2017): 158. http://dx.doi.org/10.18502/kms.v2i2.963.
Testo completoAbstract (sommario):
<p>Based on the analysis technology of processing of uranium-containing raw materials, identified potential sources of rare earth elements from among the industrial products and waste: uranium sorption tails, sulfuric acid solutions of heap leaching of uranium, man-made mineral formations from phosphate processing of uranium ores. Based on the analysis technology of processing of uranium-containing raw materials, identified potential sources of rare earth elements from among the industrial products and waste: uranium sorption tails, sulfuric acid solutions of heap leaching of uranium, man-made mineral formations from phosphate processing of uranium ores.</p>
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Sabbà, Maria Francesca, Mariateresa Tesoro, Cecilia Falcicchio e Dora Foti. "Rammed Earth with Straw Fibers and Earth Mortar: Mix Design and Mechanical Characteristics Determination". Fibers 9, n. 5 (4 maggio 2021): 30. http://dx.doi.org/10.3390/fib9050030.
Testo completoAbstract (sommario):
Raw earth is one of the oldest building materials, which is suitable for various uses: from the construction of load-bearing walls to use for plasters and finishes. The presence of straw fibers can give different behavior to this material. The present paper illustrates preliminary sensory and qualitative analyses, and subsequent laboratory tests that allow the characterization of the raw earth material with straw fibers for rammed earth constructions through mechanized compaction and the identification of a compatible earth mortar. The raw material considered in this study is mainly clayey; for this reason, a mix design usable with the pisé (or clay) technique has been developed. Cylindrical samples have been made through a press and subject to unconfined compression and indirect tensile tests. The results of the tests showed consistent tensile and compressive strength values in the context of earth materials. At the same time, a study for the realization of a mortar with the same base soil was carried out considering four mixtures, in order to investigate the best compromise between workability, shrinkage and compressive strengths. The purpose of the study was to investigate the mechanical characteristics of the local material through preliminary and laboratory tests, to classify it according to the Unified Soil Classification System (USCS) and to verify its suitability for a possible use in the construction field.
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Youcef, Abimouloud, Bali Youcef e Kriker Abdelouahed. "Comparative Study on the Impact of Sand and Lime on the Physical and Mechanical Characteristics of Unfired and Fired Earth Bricks". International Journal of Membrane Science and Technology 10, n. 3 (18 agosto 2023): 1156–63. http://dx.doi.org/10.15379/ijmst.v10i3.1698.
Testo completoAbstract (sommario):
Earth bricks represent one of the most important and widely used building materials in current era, due to its unique physical and mechanical properties compared to other materials. Earth bricks are available in two main types: raw earth bricks and fired bricks. The physical and mechanical properties differ for each type, which affects their performance in various applications and their long-term durability. Several studies have been conducted to improve the properties of raw and fired bricks and address their weaknesses. In this research, we aim to investigate the effects of adding dune sand and lime on the physical and mechanical properties of raw earth and fired bricks, and compare the results. Sand was added by 25%, while lime was added by 0, 6, 8, 10, and 12% of the soil matrix weight. Initially, we determined the properties of the raw materials used. After creating the samples, they underwent tests for bulk density, longitudinal shrinkage, compressive strength, and flexural strength. The study revealed the positive impact of adding sand on the physical and mechanical properties of raw and fired bricks. It contributed to reducing the bulk density and longitudinal shrinkage of the samples, while increasing their compressive and flexural strength to varying extents. The results also showed the positive effect of lime on the physical and mechanical properties of raw bricks, as long as it was added at a ratio not exceeding 10%. However, the addition of lime to fired bricks affected the physical properties positively but it has a negative effect on the mechanical properties.
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Niroumand, Hamed, M. F. M. Zain e Maslina Jamil. "Modern Rammed Earth in Earth Architecture". Advanced Materials Research 457-458 (gennaio 2012): 399–402. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.399.
Testo completoAbstract (sommario):
Rammed earth is a technique for building walls using the raw materials of earth, chalk, lime and gravel. Rammed earth is a structural wall system built of natural mineral soils compacted in thin layers within sturdy formwork. People have been using various forms of earth to build structures for centuries. The ancient „rammed earth‟ building technique has been used in Neolithic architecture sites and modern buildings alike. From underground green homes to other futuristic green houses. Modern architecture is a new architectural style that emerged in many countries in the decade after World War I. It was based on the “rational” use of modern materials, the principles of functionalist planning, and the rejection of historical precedent and ornament. This paper is included many examples of structures made from rammed earth using modern architecture. The result has shown the earthen buildings create safer, more people-friendly buildings. The earthen buildings are very low in embodied energy, and extremely comfortable to live in based on modern architecture.
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Yoshimura, Masahiro, Wojciech L. Suchanek e Kullaiah Byrappa. "Soft Solution Processing: A Strategy for One-Step Processing of Advanced Inorganic Materials". MRS Bulletin 25, n. 9 (settembre 2000): 17–25. http://dx.doi.org/10.1557/mrs2000.175.
Testo completoAbstract (sommario):
The term “materials cycle” is generally used to describe the synthesis of substances from raw materials (sometimes including the synthesis of manufactured raw materials), the fabrication of shaped materials, their use, and their eventual disposal. It is well known that all materials are extracted from the earth, then are converted to functional products through various fabrication processes, usually involving a high expenditure of energy, which in turn contributes to environmental problems such as global warming.
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Gjoka, Margariti, Georgios Sempros, Stefanos Giaremis, Joseph Kioseoglou e Charalampos Sarafidis. "On Structural and Magnetic Properties of Substituted SmCo5 Materials". Materials 16, n. 2 (5 gennaio 2023): 547. http://dx.doi.org/10.3390/ma16020547.
Testo completoAbstract (sommario):
SmCo5 is a well-established material in the permanent magnet industry, a sector which constantly gains market share due to increasing demand but also suffers from criticality of some raw materials. In this work we study the possibility of replacement of Sm with other, more abundant rare earth atoms like Ce-La. These raw materials are usually called “free” rare-earth minerals, appearing as a by-product during mining and processing of other raw materials. Samples with nominal stoichiometry Sm1−xMMxCo5 (x = 0.1–1.0) were prepared in bulk form with conventional metallurgy techniques and their basic structural and magnetic properties were examined. The materials retain the hexagonal CaCu5-type structure while minor fluctuations in unit cell parameters as observed with X-ray diffraction. Incorporation of Ce-La degrade intrinsic magnetic properties, Curie temperature drops from 920 K to 800 K across the series and mass magnetization from 98 Am2/kg to 60 Am2/kg; effects which trade off for the significantly reduced price. Atomistic simulations, implemented based on Density Functional Theory calculations are used in the case of the stoichiometry with x = 0.5 to calculate atomic magnetic moments and provide additional insight in the complex interactions that dominate the magnetic properties of the material.
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Galán-Arboledas, R. J., e Salvador Bueno. "Production of Ceramic Materials Using only Waste as Raw Materials". Key Engineering Materials 663 (settembre 2015): 62–71. http://dx.doi.org/10.4028/www.scientific.net/kem.663.62.
Testo completoAbstract (sommario):
From a selection of inorganic industrial waste (screen glass, steelworks ashes, coal power plant ashes, biomass power plant ash and sludge from cutting marble industry) and a waste with organic fraction (diatomaceous earth from oil filtration) it is expected to obtain ceramic materials with properties similar to those of ceramic materials used in construction and porous materials with thermal insulating capability. The ternary phase equilibrium diagram SiO2-Al2O3-CaO has been used as the main tool for the formulation of these materials. The dynamic sintering study was carried out using dilatometry techniques (DIL), thermo gravimetric analysis and differential scanning calorimetry (TG-DSC). Characterization of the manufactured material allows determining a set of basic technological properties such as fired bulk density, water absorption capacity and bending strength, in addition to thermal conductivity and microstructure by SEM-EDX, in order to obtain the necessary data to determine technical feasibility.
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KR, Dudhat. "A Potential Source of Anti-Cancer Drugs: Marine Raw Materials". International Journal of Pharmacognosy & Chinese Medicine 7, n. 2 (12 luglio 2023): 1–7. http://dx.doi.org/10.23880/ipcm-16000260.
Testo completoAbstract (sommario):
Marine populations serve as a repository for novel bioactive metabolites with a wide range of chemical configurations. The influence of marine species is highlighted in this review, with a focus on marine plants, algae, bacteria, actinomycetes, fungi, sponges, and soft corals. Disease ailment patterns are shifting, and new diseases are arising as a result of changing settings. The massive increase in the world’s population has put a strain on the available drug resources. As a result, drug companies are constantly on the search for fresh resources to help them develop effective and safe drugs to meet the growing demands of the global population. The marine environment contains an abundance of various materials for developing novel medications to treat important diseases such as cancer. Cancer is still one of the deadliest diseases on the planet. New medications with novel modes of action are desperately needed, thus much research has been done on new anticancer treatments derived from natural sources, including plants, microorganisms, and marine organisms. The anti-cancer benefits of marine natural products in in vitro and in vivo research were initially discussed, as well as their activity in tumor prevention and associated compoundinduced apoptosis and cytotoxicities.
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Medkov, Mikhail, Galina Krysenko, Dantiy Epov, Pavel Sitnik e Valentin Avramenko. "Complex processing of titanium-rare metal raw material". E3S Web of Conferences 56 (2018): 03019. http://dx.doi.org/10.1051/e3sconf/20185603019.
Testo completoAbstract (sommario):
The paper is devoted to investigation of the complex processing of titanium-rare metal raw materials with ammonium hydrodifluoride. It is stated that fluorination of the main components of the mineral raw materials with ammonium hydrodifluoride proceeds with formation of complex ammonium fluorometallates and simple fluorides. It is showed that in the process of aqueous leaching of the fluorinated mineral raw material niobium and tantalum completely pass into solution together with titanium, iron, and silicon fluoroammonium salts while all the rare-earth elements stay in the insoluble residue as complex fluorosodium salts together with CaF2. The method of separation of the fluoroammonium salts with obtaining marketable products and isolation of the rare-earth elements from the insoluble residue is offered.
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Giuffrida, Giada, Rosa Caponetto, Francesco Nocera e Massimo Cuomo. "Prototyping of a Novel Rammed Earth Technology". Sustainability 13, n. 21 (28 ottobre 2021): 11948. http://dx.doi.org/10.3390/su132111948.
Testo completoAbstract (sommario):
Buildings of the future are called to meet increasingly high-performance requirements and to ensure adequate environmental sustainability of the production and construction chain. This issue has stimulated a keen interest in the use of natural materials in construction. Among these, raw earth has proved to be particularly interesting for its intrinsic availability, sustainability, and recyclability. In Europe, the spread of raw earth building technologies has often been hindered by the lack of specific legislation regulating its use for load-bearing structures, even if in many countries, it can be noticed a widespread and well-established constructive tradition. Some transoceanic research experiences attest that unfired earth can be used, together with different types of reinforcements, to create seismic-resistant buildings. After presenting a review of the main raw earth reinforced technologies, the present study focuses on a novel reinforced and modular rammed earth construction made with natural or recycled materials, developing a technology with low energy consumption and low environmental impact, specifically designed for areas with high seismic risk. In particular, the work presents the results of a prototyping procedure aiming at developing a new seismic-resistant construction system that combines rammed earth with timber reinforcement elements and nylon/polyester ropes. These elements have a dual function: (1) they are fundamental components of the construction process (as they integrate the formwork system), and (2) they act as seismic-resistant devices once the structure is completed. In line with the performance-based approach required by the construction sector, the study aims at defining a controlled and standardised supply chain for rammed earth construction.
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Barantseva, S. E., Yu A. Klimosh, N. N. Gundilovich, A. I. Pazniak, A. A. Tolkachikova e L. N. Taran. "Prospects for the use of diabases of the crystal base of Belarus to obtain silicate materials". Proceedings of the National Academy of Sciences of Belarus, Chemical Series 56, n. 1 (19 marzo 2020): 114–24. http://dx.doi.org/10.29235/1561-8331-2020-56-1-114-124.
Testo completoAbstract (sommario):
The paper presents the study results of diabases of rare-earth and beryllium-containing deposit of the Republicof Belarusin order to determine their suitability for the production of silicate materials and products for various purposes. The data obtained allowed developing raw compositions and optimizing the technological parameters to produce glass, mineral fibers, glass ceramics, stone casting, ceramic bricks and tiles, as well as porous aggregates. The regularities of structure and phase formation during high-temperature treatment of raw compositions of silicate materials using diabases are established. The results of the work allow us to establish the features of the production of silicate materials containing diabase as main raw material of compositions, to increase mineral and raw-materials base of Belarusand to improve the environmental situation in mining enterprises.
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Huang, Xinyang, Liang Xiong e Xiaoqing Qiu. "Low-temperature route to prepare rare earth fluorides in a molten NH4NO3 system: a systematic study on the effects of NaF/Ln ratio and the reaction temperature and time". CrystEngComm 21, n. 1 (2019): 182–89. http://dx.doi.org/10.1039/c8ce01642a.
Testo completoAbstract (sommario):
A low-temperature strategy has been applied to synthesize a host of rare earth fluorides including NaLnF4 and LnF3 (Ln = rare earth) with NaF and rare earth nitrates as initial raw materials in NH4NO3 flux.
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Chen, Yuxin, Yujuan Chen, Dandan Lu e Yunren Qiu. "Synthesis of a Novel Water-Soluble Polymer Complexant Phosphorylated Chitosan for Rare Earth Complexation". Polymers 14, n. 3 (21 gennaio 2022): 419. http://dx.doi.org/10.3390/polym14030419.
Testo completoAbstract (sommario):
Combining the characteristics of rare earth extractants and water-soluble polymer complexants, a novel complexant phosphorylated chitosan (PCS) was synthesized by Kabachnik–Fields reaction with alkalized chitosan, dimethyl phosphonate, and formaldehyde as raw materials and toluene-4-sulfonic acid monohydrate (TsOH) as catalyst. The complexation properties of PCS and poly (acrylic acid) sodium (PAAS) for lanthanum ions in the solution were compared at the same pH and room temperature. In addition, the frontier molecular orbital energies of polymer–La complexes were calculated by the density functional theory method, which confirmed the complexation properties of the polymers to rare earths. The results indicate that the PCS has better water solubility compared with chitosan and good complex ability to rare earths, which can be used for rare earth separation by the complexation–ultrafiltration process.
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Verma, Shalini, Akshoy Ranjan Paul e Nawshad Haque. "Assessment of Materials and Rare Earth Metals Demand for Sustainable Wind Energy Growth in India". Minerals 12, n. 5 (20 maggio 2022): 647. http://dx.doi.org/10.3390/min12050647.
Testo completoAbstract (sommario):
Wind energy is an alternative energy generation from non-renewable energy resources. The turbine is used to exploit wind energy. Different components of a wind turbine necessitate different materials and metals. There is a dependency of the materials on foreign countries. To avoid future problems regarding the availability of these materials in India, it is necessary to forecast the quantity and the price of the materials and metals. Thus, this study mainly focuses on the estimation of the raw materials, rare earth, and critical metals used in manufacturing the wind turbine. Two wind turbines of 1.65 MW and 3.45 MW capacity, 78 m and 94 m hub height are considered for the study. The major raw materials are steel, aluminum, copper, cast iron, fiber glass with epoxy resin, and ceramic/glass. The requirement of rare earth elements (Nd) depends on the type of wind turbine direct drive or geared, and the type of generator used in the direct-drive wind turbine. The results estimated the requirement of materials and rare earth elements and the expected price in the future for 100% wind energy production in India.
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Kuhn, Britta. "Kritische Rohstoffe: Wie die EU ihre China-Abhängigkeit senken will". Wirtschaftsdienst 104, n. 7 (1 luglio 2024): 490–96. http://dx.doi.org/10.2478/wd-2024-0126.
Testo completoAbstract (sommario):
Abstract By 2030, the EU wants to extract, process and recycle domestically at least 10%, 40% and 25% respectively of the strategic raw materials it consumes. No more than 65% of these rare resources should stem from a single third country. The CRM Act’s benchmarks are primarily to be achieved via financially supported strategic projects. In addition, the EU signed raw materials partnerships with nine countries to date. However, the self-reliance targets for raw materials such as rare earth metals seem unrealistic for technical and environmental reasons. Instead, the EU should enter into more partnerships with likeminded countries.
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Huang, Yukun, Dasong Wang, Zhuo Duan, Jiang Liu, Yijun Cao e Weijun Peng. "A Novel Dissolution and Synchronous Extraction of Rare Earth Elements from Bastnaesite by a Functionalized Ionic Liquid [Hbet][Tf2N]". Minerals 12, n. 12 (12 dicembre 2022): 1592. http://dx.doi.org/10.3390/min12121592.
Testo completoAbstract (sommario):
Rare earth elements (REEs) are widely used in high-tech industries and are important basic raw materials. Bastnaesite is one of the most important minerals used in the rare earth extraction industry, and the efficient development of it is the key guarantee for the safe supply of rare earth raw materials. In this study, a novel method for dissolving bastnaesite using a carboxyl-functionalized ionic liquid ([Hbet][Tf2N]) is proposed. This innovative method provides a collaborative model with the dissolution and synchronous extraction of rare earth elements during the heating and cooling of the [Hbet][Tf2N]–H2O system. In the heating process, rare earth elements can be dissolved in a weakly acidic environment of ionic liquid without the trouble of HF escaping, and the leaching efficiencies of rare earth elements are above 95%. During the cooling of the leaching system, the rare earth ions in the dissolved state are extracted into the ionic liquid phase due to the two-phase stratification of [Hbet][Tf2N] and aqueous solution. It has been proved that rare earth ions recovery and ionic liquid regeneration can be achieved by back extraction using oxalic acid for the REEs-loaded ionic liquid.
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Nwamgbowo, Paschal, Ezekiel Nnadi, Val Hyginus Udoka Eze e Nathan Kibwami. "Quantification of Earth Material for Sustainable Road Works in Southeast Nigeria". Journal of Engineering, Technology, and Applied Science (JETAS) 5, n. 3 (26 dicembre 2023): 99–109. http://dx.doi.org/10.36079/lamintang.jetas-0503.597.
Testo completoAbstract (sommario):
This paper examines the use of earth materials in sustainable road construction in South East, Nigeria. The study aims to determine factors associated with the use of earth materials, identify limiting factors, and examine strategies to improve their use. The study population comprised 60 engineers and craftsmen using local materials. The results show limitations in the use of earth materials in sustainable road works. The study recommends contracting firms to develop better storage facilities for earth materials to prevent damage and wastage. It also suggests incorporating earth materials into construction education curriculums to sensitize students to their potential benefits. The government should adopt a policy of adapting earth materials that require minimal capital and foreign exchange and utilizing available raw materials and skills in small-scale operations. The study's findings highlight the importance of sustainable road construction in Nigeria's socio-economic growth.
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Zhao, Peng Fei, e Bin Tao. "An Analysis of Earth Folk Houses Along Shandong Canal". Applied Mechanics and Materials 71-78 (luglio 2011): 1938–44. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.1938.
Testo completoAbstract (sommario):
Earth folk houses refer to a type of traditional dwelling with their main structure built with raw earth through simple treatment without being baked in a kiln. The article discusses two types of folk houses found along Shandong Canal, including thatched earth cottages and shallow-vaulted earth cottages. It studies the layout, architectural features, building methods and materials of these buildings and explains their historical, cultural, and ecological significance.
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Novák, Viliam. "Ecosystems and Global Changes". Acta Horticulturae et Regiotecturae 24, s1 (1 maggio 2021): 70–79. http://dx.doi.org/10.2478/ahr-2021-0012.
Testo completoAbstract (sommario):
Abstract Increasing population has led to the increasing demand for food, raw materials, and energy. Continuing land use changes, intensification of its exploitation, deforestation, fossil fuel combustion, and related carbon dioxide production have been contributing to change of water and energy balance of the globe, thus changing conditions for life. Other reasons for changing conditions on the Earth are natural changes in interactions between the Earth and outer space. Actual climate change is a part of other global changes resulting in both natural and anthropogenic changes. It is mostly felt as a change of global temperature and increase of precipitation intensities and totals. Flood periods are followed by long periods without precipitations. Increasing population as well as increasing consumption of resources lead to the increasing imbalance between our planet production and consumption. To preserve good conditions for population of the Earth, it is necessary to decrease consumption of energy, raw materials, and food to reach equilibrium between Earth´s ecosystem production and consumption of the ecosystem products.
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Houben, Hugo, Alejandro Alva Balderrama e Stefan Simon. "Our Earthen Architectural Heritage: Materials Research and Conservation". MRS Bulletin 29, n. 5 (maggio 2004): 338–41. http://dx.doi.org/10.1557/mrs2004.101.
Testo completoAbstract (sommario):
AbstractEarth construction is the oldest and most universal architectural expression on our planet. The most ancient human settlements were built with raw earth, and even today at least 30% of the world's population still lives in earthen homes. The conservation of earthen architecture depends of two aspects of a global strategy. One part involves intervention to preserve existing structures, and the second involves continuing to use the construction methods and materials in contemporary and future building practices. Traditionally, earth construction has been approached in an empirical way. Only recently have those involved in the field felt it necessary to develop a specific materials research attitude. This has resulted in major technological progress over the last 20 years. The wide range of building systems emphasizes the technological diversity of earth construction. This article presents a historical perspective, along with a review of the characteristics of earth as a building material, stabilization processes, and construction methods, and a report on an ongoing research program aimed at identifying and characterizing the fundamental binding mechanisms responsible for cohesion properties in earthen construction.
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Bernardo-Arugay, Ivyleen C., Fel Jane A. Echavez, Liberty R. Lumasag, Jade P. Cahigao, Elly U. Aligno, Roben Victor M. Dispo, Sherlyn Keh D. Dionio et al. "Evaluation of Linamon Red Clay, Salvador Black Cinder and Kapatagan Diatomaceous Earth of the Southern Philippines". Minerals 13, n. 2 (11 febbraio 2023): 252. http://dx.doi.org/10.3390/min13020252.
Testo completoAbstract (sommario):
The southern island of the Philippines is abundant in silicate minerals, including the province of Lanao del Norte. However, some of these resources in the region are untapped for use as raw materials in the production of various ceramic products for industrial, pharmaceutical, and nanotechnology applications. These could include tiles, sanitary ware, dinnerware, insulating bricks, porcelain, membranes and coatings. Some of the explored minerals are the red clay in the municipality of Linamon, diatomaceous earth in Kapatagan and black cinder in Salvador. It is the aim of this study that these minerals are evaluated in terms of their physical and chemical properties so that these will be used for optimum application. The properties that were determined were their specific gravities, raw and fired surface colors, Atterberg limits, particle size distribution, thermal properties, morphologies and mineralogical compositions. Pellets were formed for each raw material and fired at two temperature levels 1000 °C and 1200 °C to evaluate their physical properties. Linamon red clay has a 38.88% cumulative passing size of 150 µm, and the black cinder of Salvador and diatomaceous earth of Kapatagan have cumulative passing sizes of 96.53% and 60.12% at 150-micron sieve, respectively. The common mineral contents of the three samples are montmorillonite, quartz and andesine. Black cinder fired at 1200 °C has the darkest shade of red with a greasy quasi-submetallic luster. It attained the highest fusion coverage on the platform among the three materials, which makes it a potential supplement or replacement for feldspar in clay-based triaxial materials for ceramic production. The diatomaceous earth has the potential to be a secondary clay content source and a good source of flux for a certain temperature range. Both the red clay and diatomaceous earth were classified as plastic materials that are suitable for brick production, and the red clay is also feasible for pottery production. These are a few of the features of the clay minerals in the region that present suitable properties for application as raw materials in the production of ceramic tiles and hollow ceramic products.
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Efrianti, Desi, Tarida Marlin e Jesica Novia. "Analisis Perencanaan Pembelian Bahan Baku Dalam Kaitannya Dengan Efisiensi Bahan Baku Pada PT. Unitex". Jurnal Ilmiah Akuntansi Kesatuan 3, n. 2 (1 agosto 2015): 082–89. http://dx.doi.org/10.37641/jiakes.v3i2.850.
Testo completoAbstract (sommario):
Purchase of raw materials is an important element in a manufacturing company because this function has a responsibility to obtain raw materials with good quantity and quality and in accordance with the requirements. Raw materials are the main source to produce and create finished goods that will be sold by company and make a profit. The production process can only be done when the supply of raw materials available in suficient quantities. The purpose ofthis study was to observe and analyze how the planning of raw materials and how they affect the efficiency ofthe availability of raw materials, as well as to deepen the blowledge of the author regarding the purchase of raw materials and raw material control. In conducting this study, the author make observations directly to the company as well as conduct interviews and analyze the data obtained. The author uses the method of descriptive analysis of qualitative data to analyze the efficiency ofplanning the purchase of raw material availability.Result of this study indicates that PT Unitex Tbk has not applied the calculation methodfor the management ofraw material inventoo. The purchase planning ofraw materials based on the needs of raw materials that can be seen from the orders of the customers. But overall, the purchase planning ofraw materials in PT Unitex is quite eficient on the availability of raw materials. It is shown that the supply of raw materials is never in a state ofzeroand is always in a state ready for production.
Keywords: purchase of raw materials, purchase planning, availability of raw materials.
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Carter, Tristan. "A true gift of mother earth: the use and significance of obsidian at Çatalhöyük". Anatolian Studies 61 (dicembre 2011): 1–19. http://dx.doi.org/10.1017/s0066154600008759.
Testo completoAbstract (sommario):
AbstractThis paper reviews 50 years of obsidian studies at Neolithic Çatalhöyük in the Konya plain, central Anatolia. A number of key issues are addressed: (1) the source of the site's raw materials, the means and forms by which the obsidian was introduced to the site and the role of Çatalhöyük in the supra-regional dissemination of these raw materials; (2) the alleged gender associations of certain obsidian goods in the burial record and beyond; (3) a more general consideration of the social significance of the circulation and consumption of obsidian at the site, including the phenomena of hoarding and gifting, plus the important role of projectiles in the creation of social identities and various forms of ritual behaviour, not least the termination of the life of a building/individual; (4) the technotypological and raw material variability through time; (5) the use of obsidian in daily practice and craft-working.
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Bodian, Seckou, Mactar Faye, Ibrahima Diaw, Pape M. Toure, Younouss Dieye e Vincent Sambou. "HYGROSCOPIC CHARACTERIZATION OF EARTH BRICKS MADE FROM LATERITE AND CLAY OF SENEGAL". International Journal of Advanced Research 10, n. 12 (31 dicembre 2022): 48–62. http://dx.doi.org/10.21474/ijar01/15807.
Testo completoAbstract (sommario):
Earth is the main raw material most used in building construction in Africa and particularly in Senegal. It is a particularly malleable material, easy to handle, from which hard bricks (unfired or fired) can be made. Thus for a good prediction of the mechanical and thermal behavior of a material, it is important to determine its hygroscopic properties. This is why our study focuses on the hygroscopic characterization of earth materials based on laterite and clay. We are mainly interested in the study of adsorption and desorption isotherms by water vapor. The adsorption and desorption isotherm curves of the samples were determined by a volumetric method using the Belsorp Aqua3 apparatus. The measurement results showed that the earth materials are hygroscopic materials. Furthermore, unfired earth materials adsorb more moisture than fired earth materials.
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Moengin, Parwadi, Nadya Adira Fabiani e Sucipto Adisuwiryo. "Perancangan Model Simulasi Tata Letak Gudang Bahan Baku Menggunakan Metode Shared Storage (Studi Kasus di PT. Braja Mukti Cakra)". JURNAL TEKNIK INDUSTRI 12, n. 1 (1 luglio 2022): 58–70. http://dx.doi.org/10.25105/jti.v12i1.13962.
Testo completoAbstract (sommario):
Intisari— PT. Braja Mukti Cakra merupakan perusahaan yang bergerak di bidang manufaktur yang menghasilkan produk komponen (machined products) yang berpresisi tinggi, berupa komponen otomotif di Indonesia. Permasalahan yang terjadi pada PT. Braja Mukti Cakra berada pada gudang bahan baku, dimana peletakan bahan baku yang belum optimal dikarenakan tidak adanya penamaan dan pembagian jenis material bahan baku pada rak atau pallet yang ada digudang. Hal ini menyebabkan operator kesulitan dalam mencari bahan baku yang akan dikirim ke lantai produksi dan mengakibatkan waktu pengambilan bahan baku menjadi lama sehingga akan terjadi keterlambatan dalam pengiriman ke lantai produksi. Tujuan dari penelitian ini adalah merancang model simulasi perbaikan tata letak gudang bahan baku dari area penyimpanan ke pintu keluar gudang yang dapat digunakan untuk mengevaluasi waktu pengambilan bahan baku dan waktu perpindahan bahan baku. Pada penelitian ini langkah awal yang dilakukan adalah mengevaluasi tata letak gudang bahan baku menggunakan checksheet untuk mengetahui kondisi gudang bahan baku saat ini dan menggunakan peta aliran proses pengambilan bahan baku untuk mengetahui aliran proses pengambilan bahan baku. Selanjutnya dibuat model simulasi awal tata letak gudang bahan baku untuk memahami sistem aktual tersebut. Model yang telah dibangun kemudian diverifikasi dan divalidasi. Jika model dinyatakan valid, dilakukan perbaikan terhadap permasalahan yang ada dengan memperbaiki tata letak gudang bahan baku dan penempatan bahan baku yang ada dengan menggunakan metode shared storage sebagai usulan tata letak gudang bahan baku. Penempatan baku baku, memperhatikan bahan baku yang memiliki tujuan yang sama dan dibuat ke dalam rak atau pallet yang sama maupun letaknya berdekatan antara rak atau pallet yang satu dengan yang lainnya sehingga mendapatkan waktu yang lebih singkat dalam proses pengiriman. Jumlah usulan perbaikan pada tata letak gudang bahan baku adalah 3 usulan. Usulan pertama adalah penambahan material handling, usulan kedua menggunakan metode shared storage dan usulan ketiga menggunakan metode shared storage dan penambahan material handling. Untuk pemilihan usulan terbaik digunakan metode benferonni dan menggunakan hasil evaluasi checksheet. Usulan yang terbaik adalah usulan ketiga dengan waktu pengambilan bahan baku dan perpindahan bahan baku ke pintu keluar gudang yaitu sebesar 71.18 jam. Dibandingkan dengan model simulasi awal yang memiliki waktu pengambilan bahan baku dan perpindahan bahan baku ke pintu keluar gudang sebesar 122.23 jam. Dari usulan terbaik ini diperoleh penghematan waktu sebesar 51.05 jam atau sebesar 41.76 %.
Abstract— PT. Braja Mukti Cakra is a company engaged in manufacturing that produces high-precision machined products, in the form of automotive components in Indonesia. The problems that occur in PT. Braja Mukti Cakra is in a raw material warehouse, where the laying of raw materials is not optimal due to the absence of naming and distribution of types of raw materials on shelves or pallets in the warehouse. This causes the operator difficulty in finding raw materials to be sent to the production floor and results in a long time for taking raw materials so that there will be delays in delivery to the production floor. The purpose of this study is to design a simulation model for improving the layout of the raw material warehouse from the storage area to the warehouse exit which can be used to evaluate the time of taking raw materials and the time of moving raw materials. In this study, the initial steps taken were evaluating the layout of the raw material warehouse using a checksheet to determine the current condition of the raw material warehouse and using a flow map of the raw material retrieval process to determine the flow of the raw material retrieval process. Furthermore, an initial simulation model of the layout of the raw material warehouse is made to understand the actual system. The model that has been built is then verified and validated. If the model is declared valid, improvements are made to the existing problems by improving the layout of the raw material warehouse and the placement of existing raw materials using the shared storage method as the proposed layout of the raw material warehouse. Placement of raw materials, paying attention to raw materials that have the same purpose and are made into the same rack or pallet or located close to each other so that they get a shorter time in the delivery process. The number of suggestions for improvements to the layout of the raw material warehouse is 3 proposals. The first proposal is the addition of material handling, the second proposal uses the shared storage method and the third proposal uses the shared storage method and the addition of material handling. To select the best proposal, the Benferonni method was used and the results of the checksheet evaluation were used. The best proposal is the third proposal with the time of taking raw materials and moving raw materials to the warehouse exit, which is 71.18 hours. Compared with the initial simulation model which has a time of taking raw materials and moving raw materials to the warehouse exit of 122.23 hours. From this best proposal, the time savings of 51.05 hours or 41.76% was obtained.
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Guliyev, Emin Anvar. "Ecology, raw materials and economic development. Expectations". Vestnik Tomskogo gosudarstvennogo universiteta. Ekonomika, n. 58 (2022): 259–67. http://dx.doi.org/10.17223/19988648/58/17.
Testo completoAbstract (sommario):
As always, ecology and raw materials will play a major role in the economic development of the world in the future. This refers to raw materials that are naturally created in the ecosystem and are indispensable for man-made industries. Environmental factors have a great impact on the processing of raw materials and future sustainable development. The formation of the impact of all environmental factors depends on the decisions made in public administration. The world's most advanced economy and technology cannot sustain itself without commodities. If we add to this the raw materials used by the productive and non-productive sectors to meet the needs of the people, the seriousness and strategic importance of the issue becomes clearer.
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Barbosa, Normando Perazzo, e Khosrow Ghavami. "Earth Construction and Sustainability". Key Engineering Materials 634 (dicembre 2014): 433–46. http://dx.doi.org/10.4028/www.scientific.net/kem.634.433.
Testo completoAbstract (sommario):
This paper presents some considerations on the impacts of industrialized construction materials to Planet Earth. It comments about sustainability and show that large part of the present generation has not met their basic needs, starting with the house. So, in this context, with the actual economic model, it becomes difficult to ensure that future generations are able to meet their own needs. Some considerations about possibilities of building with reduced environmental impact is presented. Comments about raw earth as building material are made. New possibilities to give stability to this material against water action is discussed. Finally, it shows some contemporary constructions made with earth in Brazil.
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Prudêncio, M. Isabel, M. Isabel Dias, M. José Trindade e M. Amália Sequeira Braga. "Rare earth elements as tracers for provenancing ancient ceramics". Estudos do Quaternário / Quaternary Studies, n. 8 (26 dicembre 2012): 6–12. http://dx.doi.org/10.30893/eq.v0i8.67.
Testo completoAbstract (sommario):
Clay analysis plays a crucial role in studies of ancient ceramics, contributing with answers to better understanding resource exploitation strategies, production technologies, and regional and interregional interaction patterns. The vessels are made essentially by clays, the composition of the ceramics reflectingthe origin of the clay materials used and conclusions may be inferred concerning the type of raw materials and the establishment of the geographic area of production. Different geochemical patterns found in clays from different geological contexts, consist on an important basis for the comparison with ceramics since the identification of the clays used for productions can contribute to delimit a potential area of clay resources and thus establishing provenance. This is particularly useful when no archaeological evidence of production exists. REE patterns are very important for the characterization of ceramic productions and their relation with raw materials, as subtle variations between them reflect differences in their relative behaviour in response to the chemical environment, making this group particularly useful in geochemistry studies. So, REE are crucial trace elements to pursue studies of raw materials and provenance establishment and trade routes reconstruction in ancient times.
As terras raras como indicadores geoquímicos na proveniência de cerâmica antiga - O estudo das argilas assume um papel crucial na investigação de cerâmicas antigas, contribuindo para o esclarecimento e melhor compreensão de estratégias de exploração de recursos de matérias-primas, tecnologias de produção e padrões de interacção regional e inter-regional. Os recipientes cerâmicos são essencialmente constituídos por argilas, reflectindo a sua composição a origem dos materiais argilosos usados, podendo ser retiradas conclusões relativamente ao tipo de matérias-primas, bem como ao estabelecimento de áreas geográficas de produção. Os diversos padrões geoquímicos encontrados nas argilas provenientes de diferentes contextos geológicos, constituem uma importante base para a comparação com as cerâmicas, uma vez que a identificação das argilas usadas em certas produções, pode contribuir para a delimitação da potencial área fonte de argilas, estabelecendo-se assim a sua proveniência. Este facto é particularmente relevante quando não existe evidência arqueológica de produção. Os padrões de terras raras são muito importantes para a caracterização das produções cerâmicas e sua relação com as matérias-primas, uma vez que as variaçõessubtis que apresentam reflectem diferenças no seu comportamento em resposta ao sistema químico que as rodeiam, tornando este grupo particularmente útil em estudos de geoquímica. Deste modo, as terras raras são elementos traço cruciais em estudos de matérias-primas e no estabelecimento de proveniência de cerâmicas, contribuindo para a reconstrução de rotas comerciais em tempos antigos.
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Parlato, Monica C. M., Simona M. C. Porto, Carmen Galán-Marín, Carlos Alberto Rivera-Gómez, Massimo Cuomo e Francesco Nocera. "Thermal Performance, Microstructure Analysis and Strength Characterisation of Agro-Waste Reinforced Soil Materials". Sustainability 15, n. 15 (26 luglio 2023): 11543. http://dx.doi.org/10.3390/su151511543.
Testo completoAbstract (sommario):
The use of raw-earth materials reinforced by natural fibres, i.e., livestock waste in the form of greasy wool, represents an eco-friendly alternative for a variety of construction applications. This proposal is based on the analysis of unfired adobe blocks stabilised with wool fibres for use as both structural and non-structural building materials. The influence of fibre length on the thermophysical and mechanical properties of the tested material was investigated. The thermal conductivity coefficient (λ) of raw-earth samples was assessed by following three different test setting procedures (T = 20 °C, and HR at 30%, 50%, and 70%), with the aim to evaluate the effects of different fibre lengths in the raw-earth mix. Samples reinforced by fibres 20 mm in length exhibited the lowest thermal conductivity coefficient (λ = 0.719 W/mK) obtained by a test reproducing typical indoor conditions within the Mediterranean area, i.e., T = 20 °C, and HR 50%. The best mechanical performance was exhibited by samples reinforced by fibres 40 mm in length, with a flexural and compression strength of 0.88 MPa and 2.97 MPa, respectively. The microstructure of these biocomposites was also examined with a scanning electron microscope (SEM) and an energy dispersive X-ray (EDX) to qualitatively evaluate the variation of thermal and mechanical properties due to the different adhesion among the fibres and the soil. The experimental data show good efficiency and a significant improvement in the behaviour of these materials compared to the control samples. The evaluation of the results, with the length of the fibres being the only variable of the analysed samples, allowed for the identification of the mix suitable for the best mechanical and thermal performances, depending on the final use of the material.
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Zhang, Kun, Bai Ru Lu, Xun An Zhang, Yi Hong Wang e Zhan Qu. "Research on Weibull Distribution Theory for Cubic Compressive Strength Test Method of Raw Earth Materials with Different Curing Methods and Time". Key Engineering Materials 896 (10 agosto 2021): 129–40. http://dx.doi.org/10.4028/www.scientific.net/kem.896.129.
Testo completoAbstract (sommario):
Cube compressive strength of raw-soil based mater is an important index of mechanical property. Because the test results vary by different curing modes and trial curing time, compressive strength test on 160 cubic raw-soil test-pieces which were made by 4 curing modes (natural curing, indoor curing, indoor+ preservative film curing, curing in standard curing chamber) and 4 Curing period (4d, 14d, 21d, 28d) was designed.In this study,the failure mechanism, failure mode, force mechanism of test were analyzed.Using Weibull distribution theory, the influence of different environmental factors on material strength is discussed.The research revealed that the different curing methods and curing time had remarkable effect on failure mode of material, but the load displacement curves had not affected. The compressive strength with 21d and 28d ‘s indoor curing and standard curing method were same in the test.The strength of raw soil increases with time, and the curing temperature had a significant effect on the early strength of raw soil materials, but had little effect on the later strength. The humidity had a great influence on the later growth of material strength. Constant temperature and humidity could effectively ensure the full response of internal water loss hardening of raw soil-based materials, and the strength of specimens increases obviously.The recommended curing mode and standard curing time for standard test of raw-soil test-pieces were temperature of 25-30oC, humidity of 50%-55%, and 28day, respectively.
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Yusnimar, Yusnimar, J. N. Rahman e P. Ningendah. "UTILIZATION SPENT BLEACHING EARTH AS A FILLER OF MATERIAL CONSTRUCTION". INFO-TEKNIK 22, n. 1 (14 agosto 2021): 13. http://dx.doi.org/10.20527/infotek.v22i1.11209.
Testo completoAbstract (sommario):
Spent bleaching earth (SBE) is a waste from cooking oil industry. It is categorized as one of the hazardous and toxic materials, because oil residues in it. Generally, SBE is overcome by landfill and it’s sometimes become problems. Basically SBE contains SiO2 and the size of the grain is very fine, almost the same as the fine aggregate of sand used for making brick. In this study, the making of brick used SBE with several variations (2.75% - 27.52%) of the total raw materials used. Brick making methods are based on SNI 03-0348-1989 for raw material ratio, SNI 03-0348-1989 for molding and presshing, SNI 03-6825-2002 for drying and curing. The brick quality was determined based on fineness modulus parameters, dry weight, brick absorption to water and compressive strength. Brick contain SBE 2.75% was produced with molding size of 15cm x 30cm x 9cm, it has an average dry weight of 7.80 kg, compressive strength of 8.95 MPa and absorbing power of 1.26%.
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Giuffrida, Giada, Maurizio Detommaso, Francesco Nocera e Rosa Caponetto. "Design Optimisation Strategies for Solid Rammed Earth Walls in Mediterranean Climates". Energies 14, n. 2 (8 gennaio 2021): 325. http://dx.doi.org/10.3390/en14020325.
Testo completoAbstract (sommario):
The renewed attention paid to raw earth construction in recent decades is linked to its undoubted sustainability, cost-effectiveness, and low embodied energy. In Italy, the use of raw earth as a construction material is limited by the lack of a technical reference standard and is penalised by the current energy legislation for its massive behaviour. Research experiences, especially transoceanic, on highly performative contemporary buildings made with natural materials show that raw earth can be used, together with different types of reinforcements, to create safe, earthquake-resistant, and thermally efficient buildings. On the basis of experimental data of an innovative fibre-reinforced rammed earth material, energy analyses are developed on a rammed earth building designed for a Mediterranean climate. The paper focuses on the influences that different design solutions, inspired by traditional bioclimatic strategies, and various optimised wall constructions have in the improvement of the energy performance of the abovementioned building. These considerations are furthermore compared with different design criteria aiming at minimising embodied carbon in base material choice, costs, and discomfort hours. Results have shown the effectiveness of using the combination of massive rammed earth walls, night cross ventilation, and overhangs for the reduction of energy demand for space cooling and the improvement of wellbeing. Finally, the parametric analysis of thermal insulation has highlighted the economic, environmental, and thermophysical optimal solutions for the rammed earth envelope.
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Giuffrida, Giada, Maurizio Detommaso, Francesco Nocera e Rosa Caponetto. "Design Optimisation Strategies for Solid Rammed Earth Walls in Mediterranean Climates". Energies 14, n. 2 (8 gennaio 2021): 325. http://dx.doi.org/10.3390/en14020325.
Testo completoAbstract (sommario):
The renewed attention paid to raw earth construction in recent decades is linked to its undoubted sustainability, cost-effectiveness, and low embodied energy. In Italy, the use of raw earth as a construction material is limited by the lack of a technical reference standard and is penalised by the current energy legislation for its massive behaviour. Research experiences, especially transoceanic, on highly performative contemporary buildings made with natural materials show that raw earth can be used, together with different types of reinforcements, to create safe, earthquake-resistant, and thermally efficient buildings. On the basis of experimental data of an innovative fibre-reinforced rammed earth material, energy analyses are developed on a rammed earth building designed for a Mediterranean climate. The paper focuses on the influences that different design solutions, inspired by traditional bioclimatic strategies, and various optimised wall constructions have in the improvement of the energy performance of the abovementioned building. These considerations are furthermore compared with different design criteria aiming at minimising embodied carbon in base material choice, costs, and discomfort hours. Results have shown the effectiveness of using the combination of massive rammed earth walls, night cross ventilation, and overhangs for the reduction of energy demand for space cooling and the improvement of wellbeing. Finally, the parametric analysis of thermal insulation has highlighted the economic, environmental, and thermophysical optimal solutions for the rammed earth envelope.
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Chanturia, V. A., A. I. Nikolaev e T. N. Aleksandrova. "Innovative Environmentally Safe Processes for the Extraction of Rare and Rare-Earth Elements from Complex Ores of Perplexed Material Composition". Geology of Ore Deposits 65, n. 5 (ottobre 2023): 425–37. http://dx.doi.org/10.1134/s1075701523050045.
Testo completoAbstract (sommario):
Abstract Domestic and world tendencies of involvement in the processing of ores of rare metals (RMs) and rare-earth metals (REMs) are shown. It is shown that the main direction of innovative activity is the development and application of modern breakthrough technologies for complex processing of mineral raw materials with the production of high-quality products while minimizing environmental damage. The main deposits of rare and rare-earth metals are systematized from the standpoint of the content of the main components, concentrator minerals and the main enrichment methods. The main principal technological schemes of processing of some deposits of RMs and REMs in Russia (Lovozer, Tomtor, and Afrikand deposits) are given. Options for involving technogenic and off-balance raw materials in the processing in order to extract strategic metals are considered. It is substantiated that innovative environmentally friendly processes for the extraction of rare and rare-earth metals from complex ores of complex material composition are being actively developed in Russia at present.
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Chanturiya, V. A., A. I. Nikolaev e T. N. Aleksandrova. "INNOVATIVE ENVIRONMENTALLY SAFE PROCESSES FOR RECOVERY OF RARE AND RARE-EARTH ELEMENTS FROM COMPLEX ORES OF COMPLEX MATERIAL COMPOSITION". Геология рудных месторождений 65, n. 5 (1 settembre 2023): 402–15. http://dx.doi.org/10.31857/s0016777023050040.
Testo completoAbstract (sommario):
Domestic and world tendencies of involvement in the processing of ores of rare and rare earth metals (REM) are shown. It is shown that the main direction of innovative activity is the development and application of modern breakthrough technologies for the complex processing of mineral raw materials with the production of high-quality products while minimizing environmental damage. The main deposits of rare and rare-earth metals are systematized from the standpoint of the content of the main components, concentrator minerals and the main enrichment methods. The main principal technological schemes of processing of some deposits of RM and REM in Russia (Lovozerskoe, Tomtorskoe, Afrikandskoe deposits) are given. The options for involving technogenic and off-balance raw materials in the processing in order to extract strategic metals are considered. It is substantiated that innovative environmentally friendly processes for the extraction of rare and rare earth metals from complex ores of complex material composition are being actively developed in Russia at present