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Artykuły w czasopismach na temat "Natural source materials"
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Kumar, Arun. "Natural Materials—Interesting Candidates for Carbon Nanomaterials". Physchem 1, nr 1 (19.01.2021): 4–25. http://dx.doi.org/10.3390/physchem1010002.
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This review sums up the techniques used for the synthesis of carbon nanotubes (CNTs), carbon nanofibers (CNFs), and carbon nanospheres (CNSs) by employing catalysts of natural origin. Establishing large-scale production and commercial applications of CNTs for a sustainable society is still of high apprehension. In this regard, one of the major factors is the starting materials such as precursors and catalyst sources. However, natural materials contain a minor quantity of metals or metal oxides and could be employed as a catalyst source for the synthesis of CNTs, providing the possibility to replace expensive catalyst sources. A large number of successful studies have been completed so far and confirm that these developed methods for carbon nanomaterials synthesis exhibiting high quality from common natural materials are not only possible but, most importantly, promising and scalable. This review also highlights purification methods and recent promising applications of as-synthesized CNTs.
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Lu, Xu, i Donald T. Morelli. "Natural mineral tetrahedrite as a direct source of thermoelectric materials". Physical Chemistry Chemical Physics 15, nr 16 (2013): 5762. http://dx.doi.org/10.1039/c3cp50920f.
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Molina-Santiago, Carlos, Antonio de Vicente i Diego Romero. "Bacterial extracellular matrix as a natural source of biotechnologically multivalent materials". Computational and Structural Biotechnology Journal 19 (2021): 2796–805. http://dx.doi.org/10.1016/j.csbj.2021.05.008.
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Sahiner, Nurettin, i Selin Sagbas. "Polymeric ionic liquid materials derived from natural source for adsorption purpose". Separation and Purification Technology 196 (maj 2018): 208–16. http://dx.doi.org/10.1016/j.seppur.2017.05.048.
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Paris, Oskar, Ingo Burgert i Peter Fratzl. "Biomimetics and Biotemplating of Natural Materials". MRS Bulletin 35, nr 3 (marzec 2010): 219–25. http://dx.doi.org/10.1557/mrs2010.655.
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AbstractNatural materials display a wealth of structures and fulfill a variety of functions. Hierarchical structuring is one of the keys to providing multifunctionality and to adapting to varying needs of an organism. As a consequence, the natural environment represents not only a direct and renewable source of useful materials, such as wood, plant fibers, or even proteins of pharmaceutical importance, but also an enormous “database” of structures with exceptional mechanical, optical, or magnetic properties. Rather than focusing on the direct use of natural materials, this article discusses the use of structures that appeared in evolution and have been implemented in artificial materials of an entirely different type and chemical composition. This may be done either by directly copying the structure (biotemplating) or by extracting the design principles encoded in them for the fabrication of novel bioinspired materials.
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Domanskaya, Irina K., Fedor Kapustin i Rudolf Hela. "Concrete Recycling as a Source of Polyfractional Mineral Raw Materials". Solid State Phenomena 309 (sierpień 2020): 126–31. http://dx.doi.org/10.4028/www.scientific.net/ssp.309.126.
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The problems of concrete recycling as a complex poly-reinforced composite characterized by unstable composition and properties are discussed. The peculiarity of recycling concrete scrap is that its return to the production cycle can be carried out in the form of different products: coarse aggregate (recycled aggregate), fine aggregate (sand from crushed concrete), as well as in the form of a dust-like fraction. It is shown that aggregates made of crushed concrete are inferior to natural analogues due to the presence of cement-sand mortar in their composition. Given the growing threat of depletion of natural resources, it seems appropriate to consider construction waste not only as secondary resources for the production of concrete and mortars, but also more widely: as a promising technogenic source of polymineral raw materials, including for firing technologies.
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Fakhruddin, Ahmad Kamil, i Hasmaliza M. Mohamad. "Mechanical Properties of Bioactive Glass Fabricated Using Natural Resources Materials". Materials Science Forum 1010 (wrzesień 2020): 620–25. http://dx.doi.org/10.4028/www.scientific.net/msf.1010.620.
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Bioactive glass use silica (SiO2), calcium carbonate (CaCO3), sodium carbonate (Na2CO3), phosphorus pentoxide (P2O5) as raw materials. In this work, bioactive glass (BG); 45S5 bioactive glass was synthesized using natural resources materials; rice husk ash (RHA) as silica (SiO2) source and seashell (SS) as calcium carbonate (CaCO3) source through melt derived method. All raw materials were melted at 1400 °C and water quenched. The glass frit obtained was milled and sieved then analyzed using X-ray diffraction (XRD), Fourier Transform Infrared spectroscope (FTIR) and Scanning Electron Microscope (SEM). The mechanical properties 45S5 BG pellet was observed through diametral tensile stress (DTS). The XRD and FTIR pattern for all sample synthesized using natural resources raw materials show similar pattern with control sample 45S5 synthesis using pure raw materials. The mechanical properties for all samples also have not significantly different with control samples
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Papanicolaou, Elias, i Sridhar Gopalakrishna. "Natural Convection in Shallow, Horizontal Air Layers Encountered in Electronic Cooling". Journal of Electronic Packaging 117, nr 4 (1.12.1995): 307–16. http://dx.doi.org/10.1115/1.2792110.
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A numerical study of natural convection induced in a horizontal, enclosed air layer due to a discrete, constant heat flux source at the bottom surface is carried out in this paper. The nature of the transition from conduction to a cellular convection regime for this discrete-heating case is characterized. Multiple sources are also considered and the results are compared to those for a single source. The governing equations of continuity, momentum, and energy conservation are formulated for a two-dimensional layer. The important parameters are the overall aspect ratio (length/height of the layer), the ratio of source length to total length, and the Rayleigh number. The effect of varying these parameters is investigated, and heat transfer correlations are derived, for both single and multiple sources, in the form Nus ∝ C (Ra)c>, where Nus is the Nusselt number averaged over each source. The value of C is found to depend strongly on the aspect ratio and the source size. Based on the heat transfer results, the tendency of each geometric configuration to fully attain transition to the convection regime is evaluated. This can provide guidelines for maintaining certain critical dimensions that best exploit natural convection effects, in systems where fan-driven cooling is not available.
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Klemm, Dieter, Emily D. Cranston, Dagmar Fischer, Miguel Gama, Stephanie A. Kedzior, Dana Kralisch, Friederike Kramer i in. "Nanocellulose as a natural source for groundbreaking applications in materials science: Today’s state". Materials Today 21, nr 7 (wrzesień 2018): 720–48. http://dx.doi.org/10.1016/j.mattod.2018.02.001.
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Riekstina, Daina, Tamara Krasta i Ruta Švinka. "Natural Radioactivity in Clay Ceramics and their Raw Materials in Latvia". Key Engineering Materials 788 (listopad 2018): 51–55. http://dx.doi.org/10.4028/www.scientific.net/kem.788.51.
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Natural radionuclides K-40, and Th-232, U-238 (Ra-226) decay chain products contained in building materials are the main source of radiation dose received by population and the only source of indoor radiation exposure. Present work contains results of the study of natural radionuclide activity level in clay, clay ceramics and silica bricks used in Latvia. Obtained data show that radionuclide content in different clay products can differ up to five times. However, determined activity index values for all tested materials, except fireproof bricks, were below radionuclide concentration level permitted by EU and Latvian national regulations. Comparison with analogous data from other North European and Baltic countries shows that average concentrations of natural radionuclides and activity index values for clay and clay bricks used in Latvia are on the same level as in other countries, except Sweden.
Rozprawy doktorskie na temat "Natural source materials"
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Schwanke, Anderson Joel. "Mesoestruturas porosas a partir de materiais naturais". Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12763.
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The MCM-41 mesoporous synthesis was done using rice hulls ash and chrysotile as natural alternative silica sources. For the using of these sources, chemical and thermic treatments were done in both materials. After chemical and thermic treatments, these materials were employed on the MCM-41 mesoctructures synthesis. The natural materials treated and employed in the synthesis were characterized by several techniques such as X-ray diffraction, N2 adsorption and desorption, scanning electronic microscopy and thermogravimetric analysis. MCM-41 standart samples synthetized with aerosil 200 commercial s?lica were used to evaluation. The formed material from rice hulls ash showed values from BET specific area about 468 m?.g-1, N2 adsorption and desorption isotherms and loss mass similar to reference materials. The silica from chrysotile calcined and leached was employed to mesoporous materials synthesis. The BET specific area showed values about 700 m?.g-1, N2 adsorption and desorption isotherms type IV and loss mass similar to mesoporous materials. The formed material from calcined and leached chrysotile, without calcination, applied to phenol remotion carried high performance liquid chromatography and evaluated with organophilic clays with different treatments. By the characterization techniques were proved that mesoporous materials with lesser order that reference samples. The material formed from rice hulls ash without the calcination step achieved better adsorption results than organophilic clays
A s?ntese dos mesoporosos do tipo MCM-41 foram realizadas empregando materiais naturais como cinza da casca de arroz e crisotila como fontes alternativas de s?lica. Para a utiliza??o destas fontes, tratamentos t?rmicos e qu?micos foram realizados em ambos os materiais. Os materiais naturais, ap?s tratamento t?rmico e qu?mico, foram empregados na forma??o de mesoestruturas do tipo MCM-41. Os materiais naturais, tratados e empregados na s?ntese foram caracterizados por diversas t?cnicas, como difra??o de raios-X, adsor??o e dessor??o de N2, microscopia eletr?nica de varredura e an?lise termogravim?trica. Amostras padr?es de MCM-41 sintetizadas com s?lica comercial pirolisada aerosil 200 foram utilizadas como crit?rio de compara??o. O material formado a partir da cinza da casca de arroz calcinada e lixiviada apresentou ?rea espec?fica de 468 m?.g-1, isotermas de adsor??o e dessor??o de N2 t?picas de materiais mesoporosos e eventos de perda de massa semelhantes a amostra de refer?ncia. A s?lica derivada da crisotila calcinada e lixiviada foram utilizadas para a s?ntese de materiais mesoporosos. O material apresentou valores de ?rea espec?fica BET de 700 m?.g-1, isotermas de adsor??o e dessor??o de N2 do tipo IV e perdas de massa caracter?sticas de materiais mesoporosos. O material formado a partir da cinza da casca de arroz, sem a etapa de calcina??o foi aplicado na adsor??o de fenol acompanhado por cromatografia l?quida de alta efici?ncia (CLAE) e comparado com argilas organof?licas com diversos tratamentos. Pelas t?cnicas de caracteriza??o comprova-se que os materiais s?o do possuem menor ordena??o que a amostra de refer?ncia. O material formado a partir da cinza da casca de arroz, e sem a etapa de calcina??o, obteve melhores resultados de adsor??o de fenol, se comparado ?s argilas organof?licas
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Savini, Elisa <1988>. "Design and Development of Biomineralized Nanostructured Devices from Natural Sources for Biomedical Applications". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7411/1/savini_elisa_tesi.pdf.
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The using of petroleum-based plastics is nowadays a growing problem: they are cur-rently produced from fossil fuels, a finite resource, consumed and discarded as non-degradable wastes, worsening the environment. The aim of this work was to produce newly conceived bio-based and bio-inspired solutions towards the treatment of dental diseases and air filtration in artificial ventilation. To this aim, natural polymer derived from renewable materials of food industry were used.
Following concepts of bio-mimicking and hierarchical organization, scaffolds chemically and morphologically mimicking different components of the tooth, in specific the dentin and the whole periodontium (cementum, periodontal ligament and alveolar bone), were developed. Biomineralization processes performed on appropriate polymeric matrixes were setup to synthesize hybrid materials with the same chemico-physical properties of the natural mineralized tissues (dentin, cementum and alveolar bone). Self-assembling pH-dependent process and tape-casting were applied to type I collagen to develop the thin layer mimicking the not mineralized periodontal ligament. Structural and morpho-logical features reproducing those of the natural tissues were achieved through chemi-cal cross-linking treatments and freeze-casting or electrospinning processes. In vitro investigations performed on the developed 3D scaffolds indicate good cell viability, adhesion and proliferation.
Employing biomimetic principles and natural renewable materials, also a core-shell Heat and Moisture Exchange (HME) air filter, was developed. The shell part was obtained by applying the freeze-drying process on a chemically cross-linked hydrogel developed by blending suitable ratios of gelatin and chitosan. The core part of the filter was instead reached by mixing the FeHA powder, endowed with high hyperthermic properties, with an alginate matrix.
With this approach an air filter suitable for tracheostomised patient was successfully developed, having antibacterial and heat and moisture exchange properties, able to absorb the moisture from exhaled air of the patient and to release it into the inhaled air.
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Zhang, Yan. "Comparison of Functional Porous Organic Polymers (POPs) and Natural Material Zeolite for Nitrogen Removal and Recovery from Synthetic Urine". Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7657.
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Urine comprises around 1% of domestic sewage volume but holds 80% of total nitrogen. Source separation is a sustainable way to wastewater management than traditional way due to low energy cost and preventing certain pollutants into wastewater treatment plants. Currently, removing and recovering nitrogen from source-separated urine has attracted more and more interests. Of them, ion exchange was used for removal and recovery of nitrogen in the form of ammonia from synthetic urine for potential application as a fertilizer in agriculture. No previous research studies were conducted to investigate the removal and recovery of nitrogen from hydrolyzed urine by ion exchange using POPs (porous organic polymers). So this study focused on evaluating the performance of POPs and comparing with clinoptilolite in synthetic hydrolyzed urine in terms of adsorption capacity (isotherm), adsorption rate (kinetics), regeneration rate, and cost. The ammonium removal from hydrolyzed urine using POPs was rapid with a high capacity of 68.03 mg/g than clinoptilolite (15.36 mg/g), and the regeneration efficiency of clinoptilolite and POPs can achieve 91% and 95.3%, respectively based single time use result. Although POPs had the better performance at one time use and multiple times use, it also had high materials cost. Additionally, the capacity of POP was estimated using the integrated ion exchange regeneration process model as 30.24 mg/g and 28.65 mg/g on cycle 10 and cycle 24, respectively. The regeneration efficiency of POPs was predicated as 45.4% and 38.4% in cycle 10 and cycle 24, respectively. The predicted capacity decreased with the number of cycles, but remained at about 55% of virgin POPs after 24 cycles, indicating POPs can maintain good performance after multiple reuses than clinoptilolite.
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Achoundong, Carine Saha Kuete. "Engineering economical membrane materials for aggressive sour gas separations". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50289.
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The goal is of this project was to identify principles to guide the development of high performance dense film membranes for natural gas sweetening using hydrogen sulfide and carbon dioxide gas mixtures as models under aggressive sour gas feed conditions. To achieve this goal, three objectives were developed to guide this research.
The first objective was to study the performance of cellulose acetate (CA) and an advanced crosslinkable polyimide (PDMC) dense film membrane for H₂S separation from natural gas.
The second objective was to engineer those polymers to produce membrane materials with superior performance as measured by efficiency, productivity, and plasticization resistance, and the third objective was to determine the separation performance of these engineered membrane materials under more aggressive, realistic natural gas feeds, and to perform a detailed transport analysis of the factors that impact their performance.
Work on the first objective showed that in neat CA, penetrant transport is controlled by both the solubility and mobility selectivity, with the former being more dominant, leading to a high overall CO₂/CH₄ (33) and H₂S/CH₄ (35) ideal selectivities. However, in uncrosslinked PDMC, H₂S/CH₄ selectivity favored sorption only, whereas CO₂/CH₄ selectivity favored both mobility and sorption selectivity, leading to a high CO₂/CH₄ (37) but low H₂S/CH₄ (12) ideal selectivities. However, the latter polymer showed more plasticization resistance for CO₂.
In the second objective, both materials were engineered. A new technique referred to as “GCV-Modification” was introduced in which cellulose acetate was grafted using vinyltrimethoxysilane (VTMS), then hydrolyzed and condensed to form a polymer network. PDMC was also covalently crosslinked to enhance its performance. GCV-Modified CA showed significant performance improvements for H₂S and CO₂ removal; the permeability of CO₂ and H₂S were found to be 139 and 165 Barrer, respectively, which represented a 30X and 34X increase compared to the pristine CA polymer. The H₂S/CH₄ and CO₂/CH₄ ideal selectivities were found to be 39 and 33, respectively. Crosslinked PDMC showed a higher CO₂/CH₄ selectivity of 38 with a better plasticization resistance for CO₂ and H₂S.
In the third objective, these materials were tested under aggressive ternary mixtures of H₂S/CO₂/CH₄ with both vacuum and nonvacuum downstream. Even under aggressive feed conditions, GCV-Modified CA showed better performance vs. PDMC, and it remained were fairly stable, making it a potential candidate for aggressive sour gas separations, not only because of its significantly higher productivity, which will help decrease the surface area needed for separation, thereby reducing operating costs, but also because of the lower cost of the raw material GCV-Modified CA compared to PDMC.
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Junior, Vilmar Barbosa. "Tanino como macromonômero na síntese de polímeros fenólicos visando a preparação de compósitos reforçados com material de origem vegetal". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-25102007-113753/.
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No presente trabalho, tanino (macromolécula de origem natural) foi utilizado como substituinte de fenol na formulação de matriz fenólica usada na preparação de compósitos, o que é possível devido à presença de anéis fenólicos sua estrutura. Os compósitos de matriz taninofenólica (50% em massa de tanino) apresentaram propriedades mecânicas superiores aquelas dos compósitos de matriz fenólica, quando reforçados pelo mesmo tipo de fibra, mostrando que a substituição de material obtido em larga escala a partir de fonte fóssil (fenol) é viável e pode ser feita por material obtido de fonte renovável (tanino) sem comprometimento de propriedades. Ainda, avaliou-se para propriedades de compósitos com diferentes tipos de reforços (fibras e cargas) através de caracterizações via análise térmica (TG e DSC), análise dinâmico-mecânica, espectroscopia na região do infravermelho, resistência ao impacto, absorção de água e microscopia eletrônica de varredura. Os ensaios de resistência ao impacto indicaram uma melhora de propriedades mecânicas quando da incorporação de fibras vegetais (juta e coco) nos termorrígidos fenólico e taninofenólico, além de mostrar que as fibras de juta reforçam as matrizes taninofenólicas mais eficientemente que as fibras de coco. As cascas da árvore de Acácia Negra, ricas em taninos, também foram utilizadas como agentes de reforço em compósitos na forma de fibras e cargas, obtidos através de desfibramento e pulverização, respectivamente. A utilização destes reforços, em diferentes proporções de massa, em compósitos de matriz taninofenólica (50% de tanino) levou a diferenças nas propriedades do compósito, com destaque para baixa absorção de água. Provavelmente, a presença de taninos no reforço e na matriz levou a intensas interações na interface fibra/matriz, diminuindo o número de vazios que podem alojar moléculas de água. As fibras de coco foram tratadas por ultra-som, a fim de avaliar a influência deste tratamento nas propriedades da fibra e dos compósitos reforçados por elas. As fibras de coco tratadas e não-tratadas foram caracterizadas quanto à composição química, índice de cristalinidade, ensaio de tração e microscopia eletrônica de varredura. Os resultados obtidos mostraram que o ultra-som é um tratamento promissor, pois modifica a morfologia da superfície das fibras sem levar à degradação química, sendo que a separação dos feixes de fibra que ocorre permite melhor interação fibra/matriz na interface, obtendo-se assim compósitos mais resistentes à água. Outros tratamentos utilizados em trabalhos anteriores a este, como mercerização, diminuem absorção de água dos compósitos por ela reforçados, ao custo de parcial degradação das fibras lignocelulósicas. No presente trabalho, materiais preparados a partir de matéria-prima oriunda de fontes renováveis foram processados, o que vem de encontro aos anseios atuais. Os compósitos obtidos têm potencial para aplicações não estruturais, por exemplo, em partes internas de veículos automotivos.In the present work, tannin (macromolecule obtained from natural source) was used as substitute of phenol in the formulation of phenolic matrix composites, due to the presence of phenolic rings in its structure. The tanninphenolic matrix composites (50% w/w of tannin) presented mechanical properties better than those of phenolic matrix composites showing that substitution of material obtained in large scale from non-renewable source (phenol) can be done by material obtained from natural source (tannin) without compromising the properties of the composite. The tanninphenolic matrix composites reinforced by different reinforcing agents (fibers and particules) were characterized by different techniques: Izod impact strength, thermogravimetry (TG), differential scanning calorymetry (DSC), infrared spectroscopy (IV), dynamic-mechanical analysis (DMA) and scanning electron microscopy (SEM). The Izod impact strength showed an improvement of mechanical properties due to the incorporation of natural fibres (jute and coir) in the phenolic and tanninphenolic matrices and also the better reinforcement of these matrices by jute fibres, when compared to coir fibres. The barks of Acacia Mimosa (high content of tannin) were also used as reinforcing agents of the tanninphenolic matrices in the forms of fibres and particules. The presence of these reinforcing agents in the matrix led to differences in the properties of the composites, highlighted by its lower water uptake. The presence of tannins in both reinforcing agents and matrix enhanced the fiber/matrix interactions, lowering the voids that increase water uptake. The coir fibres were treated by ultrasound, in order to evaluate the influence of this treatment in the properties of the fibres and, therefore, the composites reinforced with them. Besides chemical composition, all the fibres were characterized by the following techniques: X-ray diffraction, tensile strengh, infrared spectroscopy (IV), and scanning electron microscopy (SEM). The results revealed that the ultrasound is a promising treatment of fibres for the processing of composites, because it modifies the morphology of the surface of fibres without leading them to chemical degradation. The separation of fiber beams allows enhancement of the fiber/matrix interactions, leading to composites with lower water absorption capacity. Other treatments, such as mercerization, for example, improved the impregnation of the fibres by the pre-polymer, leading to composites with better properties, at expenses of partial degradation of lignocellullosic fibres. In the present work, composites were prepared using material obtained from renewable source, according to the purpose of this work. The obtained composites presents potential for non-structural applications, such as, internal panels of cars, for example.
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Bellot-Gurlet, Ludovic. "De la source aux techniques. Méthodologies d'analyses élémentaires et structurales et physico-chimie de matériaux du patrimoine culturel". Habilitation à diriger des recherches, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00540472.
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L'étude de la physico-chimie des matériaux du patrimoine culturel peut nous renseigner sur les activités humaines dans lesquelles les objets anciens ont été impliqués, depuis leur sélection, leur transport, leurs transformations, leurs usages et jusqu'à leur abandon. De plus la préservation de cet héritage culturel nécessite la compréhension des mécanismes l'altération afin de contrôler et prévenir les processus de dégradation. Ce manuscrit présente les activités de recherches développées autour de la physico-chimie des matériaux anciens réalisées depuis mon doctorat, période au cours de laquelle les questions abordées se sont diversifiées. Les travaux s'articulent actuellement autour de trois axes : “archéométrie”, avec les études de provenance et l'histoire des techniques ; “conservation”, avec l'étude et le diagnostic des dégradations ; enfin “analogues”, avec les mécanismes d'altérations à long terme. Les approches analytiques mises en œuvre se sont élargies, partant des analyses élémentaires pour aborder puis développer les caractérisations structurales à l'aide des spectroscopies vibrationnelles (Raman et infrarouge). Après une présentation de mes activités d'enseignement et d'encadrement, trois chapitres retracent les sujets de recherche abordés. La première partie : “Physico-chimie d'un verre naturel : l'obsidienne, un marqueur des réseaux d'échange”, présente les travaux effectués sur les études de provenance de l'obsidienne avec des approches fondées sur leurs compositions élémentaires puis leurs propriétés structurales. La seconde : “Produits de corrosion des métaux ferreux : de la caractérisation structurale des analogues aux mécanismes et à la prévision de l'altération”, expose les méthodologies introduites avec la spectroscopie Raman pour caractériser les produits de corrosion. Les informations fournies sont destinées à faire évoluer les mécanismes envisagés et proposer des éléments de diagnostic pour la conservation et la restauration. La dernière partie : “Projets en développement : les substances naturelles organiques issues d'objets du patrimoine” présente les premiers résultats obtenus sur un axe de recherche récemment ouvert. Il s'agit de contribuer à une reconnaissance des produits utilisés, soit bruts, soit transformés, soit mis en œuvre dans des vernis, pour des problématiques de circulation des matières premières, d'histoire des techniques ou de conservation.
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Rakotondrandisa, Aina. "Modélisation et simulation numérique de matériaux à changement de phase". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR051/document.
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Nous développons dans ce travail de thèse un outil de simulation numérique pour les matériaux à changement de phase (MCP), en tenant compte du phénomène de convection naturelle dans la phase liquide, pour des configurations en deux et trois dimensions. Les équations de Navier-Stokes incompressible avec le modèle de Boussinesq pour la prise en compte des forces de flottabilité liées aux effets thermiques, couplées avec une formulation de l’équation d’énergie suivant la méthode d’enthalpie, sont résolues par une méthode d’éléments finis adaptatifs. Une approche mono-domaine, consistant à résoudre les mêmes systèmes d’équations dans les phases solide et liquide, est utilisée. La vitesse est ramenée à zéro dans la phase solide, en introduisant un terme de pénalisation dans l’équation de quantité de mouvement, suivant le modèle de Carman-Kozeny, consistant à freiner la vitesse à travers un milieu poreux. Une discrétisation spatiale des équations utilisant des éléments finis de Taylor-Hood, éléments finis P2 pour la vitesse et éléments finis P1 pour la pression, est appliquée, avec un schéma d’intégration en temps implicite d’ordre deux (GEAR). Le système d’équations non-linéaires est résolu par un algorithme de Newton. Les méthodes numériques sont implémentées avec le logiciel libre FreeFem++ (www.freefem.org), disponible pour tout système d’exploitation. Les programmes sont distribués sous forme de logiciel libre, sous la forme d’une forme de toolbox simple d’utilisation, permettant à l’utilisateur de rajouter d’autres configurations numériques pour des problèmes avecchangement de phase. Nous présentons dans ce manuscrit des cas de validation du code de calcul, en simulant des cas tests bien connus, présentés par ordre de difficulté croissant : convection naturelle de l’air, fusion d’un MCP, le cycle complet fusion-solidification, chauffage par le bas d’un MCP, et enfin, la solidification de l’eauIn this thesis we develop a numerical simulation tool for computing two and three-dimensional liquid-solid phase-change systems involving natural convection. It consists of solving the incompressible Navier-Stokes equations with Boussinesq approximation for thermal effects combined with an enthalpy-porosity method for the phase-change modeling, using a finite elements method with mesh adaptivity. A single-domain approach is applied by solving the same set of equations over the whole domain. A Carman-Kozeny-type penalty term is added to the momentum equation to bring to zero the velocity in the solid phase through an artificial mushy region. Model equations are discretized using Galerkin triangular finite elements. Piecewise quadratic (P2) finite-elements are used for the velocity and piecewise linear (P1) for the pressure. The coupled system of equations is integrated in time using a second-order Gear scheme. Non-linearities are treated implicitly and the resulting discrete equations are solved using a Newton algorithm. The numerical method is implemented with the finite elements software FreeFem++ (www.freefem.org), available for all existing operating systems. The programs are written and distributed as an easy-to-use open-source toolbox, allowing the user to code new numerical algorithms for similar problems with phase-change. We present several validations, by simulating classical benchmark cases of increasing difficulty: natural convection of air, melting of a phase-change material, a melting-solidification cycle, a basal melting of a phase-change material, and finally, a water freezing case
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Dvořák, Jakub. "Návrh objektu využívajícího alternativní materiály se zohledněním požadavků na trvale udržitelný rozvoj". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-396157.
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This diploma thesis deals with the design of a small family house, which construction uses alternative building materials. The first part of the thesis is devoted to the world, European and Czech legislation related to sustainable development. The concept of ecological construction, which focuses on the possibilities of reducing the negative impacts of construction production on the environment at various stages of construction and on energy, material, water and waste management, is also presented. The thesis also describes advantages and disadvantages of particular solutions. In the second part of the thesis, which based on theoretical knowledge, is the design of a family house from alternative materials worked out. The design of the study in the scale of 1:100 consists of measured floor plan drawings of all storeys, characteristic measured section drawings, layout plans with displayed furniture and equipment, elevation drawings of particular facades, roof drawings and situation design. The drawing part is accompanied by a text part. The processed design is compared to the reference building and then evaluated from the point of view of functional, economic, environmental and social requirements.
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VENUTA, MARIA LUISA. "La città da energivora a nodo attivo delle reti di produzione e di scambio energetico". Doctoral thesis, Università Cattolica del Sacro Cuore, 2007. http://hdl.handle.net/10280/85.
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Il concetto di rete dell'informazione può diventare uno schema logico con cui descrivere l'evoluzione delle politiche sulle energie rinnovabili e sulla sostenibilità?
La ricerca è stata svolta analizzando l'architettura delle due reti (internet e reti energetiche) e l'evoluzione del bene prodotto e distribuito nella rete energetica, l'energia, esplicitando l'accessibilità da parte della distribuzione mondiale delle risorse petrolifere tradizionali e delle risorse rinnovabili. La struttura metodologica del progetto di ricerca si basa due tipi di analisi teorica:
1) l'analisi della nascita delle società in rete attraverso le teorie di Manuel Castells (concetto di spazio di flussi) e di Saskia Sassen e l'evoluzione delle città (cap.2 e cap.5)
2) le analisi dei flussi dei materiali e delle energie avendo come riferimento metodologico l'approccio ecologico ideato dai ricercatori dell'istituto per il Clima, l'Ambiente e l'Energia di Wuppertal, Germania (cap.3 e cap.4)
La contraddizione tra città innovative e città che sono ai livelli di enormi discariche o di baraccopoli è esposta nel cap.6 attraverso casi studio e progetto dei Programmi Europei.
Nell'ultimo capitolo (cap.7) si riassumono le ipotesi di partenza e i risultati della ricerca e si espongono le questioni aperte.Can internet logic scheme be used as a basis to describe public policies evolution on renewable energies production and sharing in urban areas all over the world? The research project analyses the two networks (internet and energetic grids) architectures in actual and future urban areas. This analysis is connected with present and future forecasts energy productions from traditional fuels and from renewable sources. Theoretical analysis is conducted following a double conceptual pathway: - societal networks (Manuel Castells theory) and urban areas evolution (Saskia Sassen and Mike Davis) in order to picture the evolution of cities and towns in modern economies and in developing countries (Chapters 2 and 5); - Material and Energy Flow Analysis (approach by Wuppertal Institute for Climate, Environment and Energy) applied to renewable energy (Chapters 3 and 4) In Chapter 6 case studies are exposed on the deep cleavage between two different worlds: innovative, rich towns on a side and the landfills cities, slums on the other side. In the last part hypothesis and thesis are put together and open questions are explained (Chapter 7).
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VENUTA, MARIA LUISA. "La città da energivora a nodo attivo delle reti di produzione e di scambio energetico". Doctoral thesis, Università Cattolica del Sacro Cuore, 2007. http://hdl.handle.net/10280/85.
Pełny tekst źródłaStreszczenie:
Il concetto di rete dell'informazione può diventare uno schema logico con cui descrivere l'evoluzione delle politiche sulle energie rinnovabili e sulla sostenibilità?
La ricerca è stata svolta analizzando l'architettura delle due reti (internet e reti energetiche) e l'evoluzione del bene prodotto e distribuito nella rete energetica, l'energia, esplicitando l'accessibilità da parte della distribuzione mondiale delle risorse petrolifere tradizionali e delle risorse rinnovabili. La struttura metodologica del progetto di ricerca si basa due tipi di analisi teorica:
1) l'analisi della nascita delle società in rete attraverso le teorie di Manuel Castells (concetto di spazio di flussi) e di Saskia Sassen e l'evoluzione delle città (cap.2 e cap.5)
2) le analisi dei flussi dei materiali e delle energie avendo come riferimento metodologico l'approccio ecologico ideato dai ricercatori dell'istituto per il Clima, l'Ambiente e l'Energia di Wuppertal, Germania (cap.3 e cap.4)
La contraddizione tra città innovative e città che sono ai livelli di enormi discariche o di baraccopoli è esposta nel cap.6 attraverso casi studio e progetto dei Programmi Europei.
Nell'ultimo capitolo (cap.7) si riassumono le ipotesi di partenza e i risultati della ricerca e si espongono le questioni aperte.Can internet logic scheme be used as a basis to describe public policies evolution on renewable energies production and sharing in urban areas all over the world? The research project analyses the two networks (internet and energetic grids) architectures in actual and future urban areas. This analysis is connected with present and future forecasts energy productions from traditional fuels and from renewable sources. Theoretical analysis is conducted following a double conceptual pathway: - societal networks (Manuel Castells theory) and urban areas evolution (Saskia Sassen and Mike Davis) in order to picture the evolution of cities and towns in modern economies and in developing countries (Chapters 2 and 5); - Material and Energy Flow Analysis (approach by Wuppertal Institute for Climate, Environment and Energy) applied to renewable energy (Chapters 3 and 4) In Chapter 6 case studies are exposed on the deep cleavage between two different worlds: innovative, rich towns on a side and the landfills cities, slums on the other side. In the last part hypothesis and thesis are put together and open questions are explained (Chapter 7).
Książki na temat "Natural source materials"
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Natural materials: Sources, properties, and uses. Amsterdam: Elsevier/Architectural Press, 2006.
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International Symposium on Polymeric Renewable Resource Materials (2nd 1985 Miami Beach, Fla.). Renewable-resource materials: New polymer sources. New York: Plenum Press, 1986.
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World Congress of Philosophy (19th 1993 Moscow, Russia). Philosophy of natural science: A source of culture innovations : materials to "Round Table" XIX World Congress of Philosophy, 22-28 August 1993, Moscow = Filosofii͡a︡ estestvoznanii͡a︡ : istochnik kulʹturnykh innovat͡s︡iĭ : materialy k kruglomu stolu XIX Vsemirnogo filosofskogo kongressa, 22-28 avgusta 1993, Moskva. Kharkov: Ukrainian Ministry of Education, Kharkov State University, 1993.
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Zhou, J. Traditional Chinese medicines: Molecular structures, natural sources, and applications. Wyd. 2. Aldershot, England: Ashgate, 2003.
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Ara, DerMarderosian, Beutler John A i Facts and Comparisons (Firm), red. The Review of natural products: The most complete source of natural product information. Wyd. 3. St. Louis, Mo: Facts and Comparisons, 2002.
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Agafonov, Vyacheslav, Sergey Bogolyubov, Liya Vasil'eva, Galina Vyphanova, Dmitriy Gorohov, Natal'ya Zhavoronkova, Inna Ignat'eva i in. Sources of environmental law. ru: INFRA-M Academic Publishing LLC., 2022. http://dx.doi.org/10.12737/1913253.
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The monograph summarizes new relevant materials and topics. The study of the sources (forms) of environmental and natural resource law, legislation on environmental assessment and environmental control (supervision), provisions of land and other codes as forms of law, mechanisms for regulating environmental management, as well as the evolution of sources of law in the field of agriculture.
The complex nature of environmental law is demonstrated, the constitutional, legislative, and political foundations of environmental development, the unified state environmental policy of the Russian Federation and a number of foreign states are outlined. The genesis and systematization of forms of atmospheric air protection, specially protected natural territories of Russia, Belarus and Kazakhstan, legal regulation of waste management, international and national measures of adaptation to climate change are reflected.
The legislation on land reclamation, land management, subsoil use, forest management, water use, fishing and conservation of aquatic biological resources in the system of sources of environmental law is analyzed; the issues of intersectoral communication of environmental, urban planning, information, energy, civil legislation and law are considered.
Examples from the field of law enforcement are given. The idea of ecologization of sources (forms), institutions, categories, norms of branches of Russian law is being developed.
For lawyers — scientists and practitioners, teachers, postgraduates, masters, law students, and other specialists interested in the theory and practice of lawmaking and the application of environmental law.
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Ulber, Roland. Renewable raw materials: New feedstocks for the chemical industry. Weinheim, Germany: Wiley-VCH, 2011.
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Hirt, Hans Martin. Natural medicine in the tropics 1: Foundation text : tropical plants as a source of health care : production of medicines and cosmetics. Wyd. 3. Winnenden, Germany: Anamed, 2008.
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Zhou, Jiaju. Encyclopedia of Traditional Chinese Medicines - Molecular Structures, Pharmacological Activities, Natural Sources and Applications: Vol. 6: Indexes. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg, 2011.
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Miguel, Herrero, red. Bioactive compounds from marine foods: Plant and animal sources. Chichester, West Sussex: IFT Press, Wiley Blackwell, 2014.
Znajdź pełny tekst źródłaCzęści książek na temat "Natural source materials"
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Reineccius, Gary. "Natural Flavoring Materials". W Source Book of Flavors, 176–364. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-7889-5_7.
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Šťastná, Aneta, i Richard Přikryl. "Determination of Source Areas of Natural Stones: A Methodology Approach Applied to Impure Crystalline Limestones". W Materials, Technologies and Practice in Historic Heritage Structures, 157–75. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-2684-2_9.
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Schwanke, Anderson Joel, Rosana Balzer i Sibele Pergher. "Microporous and Mesoporous Materials from Natural and Inexpensive Sources". W Handbook of Ecomaterials, 1–22. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-48281-1_43-1.
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Schwanke, Anderson Joel, Rosana Balzer i Sibele Pergher. "Microporous and Mesoporous Materials from Natural and Inexpensive Sources". W Handbook of Ecomaterials, 3379–99. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-68255-6_43.
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Nousiainen, P., J. Kontro, P. Maijala, E. Uzan, A. Hatakka, A. Lomascolo i J. Sipilä. "Lignin Model Compound Studies To Elucidate the Effect of “Natural” Mediators on Oxidoreductase-Catalyzed Degradation of Lignocellulosic Materials". W Functional Materials from Renewable Sources, 229–42. Washington, DC: American Chemical Society, 2012. http://dx.doi.org/10.1021/bk-2012-1107.ch012.
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Peltola, Heli, Tero Heinonen, Jyrki Kangas, Ari Venäläinen, Jyri Seppälä i Lauri Hetemäki. "Climate-Smart Forestry Case Study: Finland". W Forest Bioeconomy and Climate Change, 183–95. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-99206-4_11.
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AbstractFinland is the most forested country in the EU – forests cover 74–86% of the land area, depending on the definition and source. Increasing carbon sequestration from the atmosphere, and by storing it in forests (trees and soil) will be one important part of the Finnish climate smart forestry strategy. However, just maximizing the carbon storage of forests may not be the best option in the long run, although it may provide the best climate-cooling benefits in the short term. This is because the increasing risks of large-scale natural disturbances may turn forests, at least partially, into carbon sources. The climate change adaptation and mitigation should therefore be considered simultaneously. Different adaptation and risk management actions will be needed in Finnish forests in the coming decades to increase forest resilience to multiple damage risks. This could be done, for example, by increasing the share of mixtures of conifers and broadleaves forests instead of monocultures. Yet, the CSF strategy should also include the production of wood-based products that act as long-term carbon storage and/or substitute for more GHG-emission-intensive materials and energy. Doing this in a way which also enhances biodiversity and sustainable provisioning of multiple ecosystem services, is a key. Moreover, increasing forest land – for example, by planting on abandoned or low-productivity agricultural land, especially on soils with a high peat content – would enhance climate change mitigation.
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Leonida, Mihaela D. "Materials From Natural Sources and Those Prepared in the Iconographer’s Studio or in the Peasant Household". W SpringerBriefs in Materials, 9–13. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04828-4_2.
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Larsson, Jesper, i Eva-Lotta Päiviö Sjaunja. "Lule Lappmark and Sources". W Self-Governance and Sami Communities, 37–70. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-87498-8_3.
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AbstractIn this chapter, we describe the study area, Lule lappmark, and the sources we used. We discuss how land use was influenced by differences in environmental settings and argue that empirical material from Lule lappmark in northern Sweden can be used to draw valid conclusions about general features regarding Sami land use and property rights in other regions as well. We introduce the reader to our interpretations of some important concepts necessary to understand the development of natural resource governance and argue that some earlier interpretations of the pre-modern Sami organization have led to misconceptions about that development.
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Carrillo, Karla L. Tovar, i Takaomi Kobayashi. "Natural Material Source of Bagasse Cellulose and Their Application to Hydrogel Films". W Applied Environmental Materials Science for Sustainability, 19–43. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1971-3.ch002.
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Among all biomass sources, cellulose is the most diverse material sourced from plants and is abundant in nature. It possesses some promising properties such as biodegradability, biocompatibility and hydrophilicity. In several industrial biomasses, the waste products especially for food manufacture have high content of cellulose and their disposals are serious in reuse problem. Therefore, people have given attention with regard to their regeneration to the useful materials. In this chapter, it is worth noting to describe that natural biomass cellulose is usefully applied with the regeneration to functional hydrogel films. The treatment processes of the bagasse waste used as a main source of cellulose and the fabrication of hydrogel films are described and their potential characteristics, especially on the medical field are reviewed.
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Anjelh Baqiya, Malik, Retno Asih, Muhammad Ghufron, Mastuki, Dwi Yuli Retnowati, Triwikantoro i Darminto. "Ferrite-Based Nanoparticles Synthesized from Natural Iron Sand as the Fe3+ Ion Source". W Nanocrystalline Materials. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.88027.
Pełny tekst źródłaStreszczenia konferencji na temat "Natural source materials"
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Yuan, Meng. "Source Tracing and Application of Regional Natural Materials in Ecological Buildings". W 2018 International Conference on Education Science and Social Development (ESSD 2018). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/essd-18.2018.77.
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López-Coto, I., J. P. Bolivar, J. L. Mas, R. García-Tenorio, Anselmo Salles Paschoa i Friedrich Steinhäusler. "Characterization of Porous Materials as Radon Source and its Radiological Implications". W THE NATURAL RADIATION ENVIRONMENT: 8th International Symposium (NRE VIII). AIP, 2008. http://dx.doi.org/10.1063/1.2991196.
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Savanina, Yanina. "INTEGRATED USE OF NATURAL INSECT RAW MATERIALS I'M IN." W NEW TECHNOLOGIES IN MEDICINE, BIOLOGY, PHARMACOLOGY AND ECOLOGY. Institute of information technology, 2021. http://dx.doi.org/10.47501/978-5-6044060-1-4.35.
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The article discusses the possibility of using migratory locust as a resource - a seasonal, but abundant and predictable, possible source of fodder protein, as well as chitin and its deriva-tives. Comparison with traditional resources of such raw materials.
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Nogata, Fumio. "Learning About Design Concepts From Natural Functionally Graded Materials". W ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0646.
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Abstract The goal of this report is to provide a new insight into nature as a source of inspiration for optimizing mechanical properties of structural components through functionally graded and/or multi-phased microstructures. It is shown that biological structure is designed to have uniform strength at all positions in both radial and axial directions. Design principles and processes in plants show that plants have a cell-based sensing system for external mechanical stimuli that plays a similar role as the piezoelectric effect in bones, i.e., mechanical stress/strain changes the stationary electric potential of plants, theryby influencing the growth activity of their load carrying members. The ingenious construction of some selected biomaterials demonstrates clearly that it would be better to spend more time and money on developing functionally graded materials governed by uniform strength; for example, structure using the optimal placement of fibers, various microstructures, porous or cellular structures, etc., rather than developing new materials with high-stiffness.
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Zhang, Yangjun, Chaokui Qin, Pengjun Liu i Chunyan Tian. "Discussion about reference gas for multi-source natural gases in light of interchangeability". W 2013 International Conference on Materials for Renewable Energy and Environment (ICMREE). IEEE, 2013. http://dx.doi.org/10.1109/icmree.2013.6893816.
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Jawale, Pradeep, Ashok Mache, Vedant Irabatti i Akshay Umate. "Natural Fiber Base Composite Material Solution for Vibration Damping of ICE and Next-Generation Vehicle". W WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2023. http://dx.doi.org/10.4271/2023-01-0728.
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<div class="section abstract"><div class="htmlview paragraph">Vibration control plays a critical role in conventional as well as next-generation vehicles. Construction of the vehicle, road conditions, and driving patterns are the major sources of the vibrations that cause discomfort to the passengers in the vehicle. Composite material is being looked at as an alternative material in the automotive sector due to its higher specific strength and good damping properties. In this research, the test specimen of steel plate used in automotive has been considered. The damping vibration test has been carried out on the test specimen by using the FFT analyzer to evaluate the natural frequency and damping. Thereafter, the hybrid composite material is developed with the natural fibers as reinforcement with steel plate to reduce the vibrations. The test specimens with different layers of damping materials have been prepared for this research. Jute, hemp, banana, and flax are used for the preparation of different composite materials. This research has been further extended to vehicle-level applications like tyre, which is a common source of vibration in vehicle. Significant vibration reduction has been achieved by using natural fiber base composite materials and with different layers.</div></div>
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Berechet, Mariana Daniela, Demetra Simion, Maria Stanca i Cosmin Andrei Alexe. "Protein Extracts from Fish Head as Natural Fertilizer for Corn Plants". W The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.iv.1.
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The amino acid composition in the hydrolysates of fish proves to be a most promising source of protein. Two extracts from fish by-products (P1, from the head and fins of sturgeon and P2, from the cartilage of sturgeon head and fins) were obtained as liquids that were dried at 40°C. Liquid extracts were characterized physico-chemically (dry matter 3.86% and 4.25%, protein content 1.44% and 3.25%), and particle size (247nm, 94% and 4148nm, 65% majority populations for P1 and P2) and zeta potential (-27.4mV and -15.8mV) were measured. The smaller particle size for the P1 extract led to its choice for treatments applied in the growth of corn seeds. Four samples of concentrations of 0.5%, 1%, and 1.5% and control concentrations were experimented, each on 25 corn seeds, observing the growth of plants over a period of 13 days. A 13% higher increase of the corn plants was obtained in the case of the sample treated with 1.5% fish protein extract, P1. Throughout the experiments, the P1 sample with 1.5% fish protein extract had higher increases than the control sample. These results suggest that extracts from the head by-products of sturgeon fish could be used in agriculture as a nutrient in the growth of corn plants.
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Tamburello, David, Bruce Hardy i Martin Sulic. "Multi-Component Separation and Purification of Natural Gas". W ASME 2018 Power Conference collocated with the ASME 2018 12th International Conference on Energy Sustainability and the ASME 2018 Nuclear Forum. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/power2018-7537.
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Over the past decade, several technical developments (such as hydraulic fracturing) have led to an exponential increase in discovering new domestic natural gas reserves. Raw natural gas composition can vary substantially from source to source. Typically, methane accounts for 75% to 95% of the total gas, with the rest of the gas containing ethane, propane, butane, other higher hydrocarbons, and impurities, with the most common including H2O, CO2, N2, and H2S. All natural gas requires some treatment, if only to remove H2O; however, the composition of natural gas delivered to the commercial pipeline grids is tightly controlled. Sub-quality natural gas reserves, which are defined as fields containing more than 2% CO2, 4% N2, or 4 ppm H2S, make up nearly half of the world’s natural gas volume. The development of sub-quality, remote, and unconventional fields (i.e. landfill gas) can present new challenges to gas separation and purification methods. Adsorbent technologies, such as the use of activated carbons, zeolites, or metal-organic frameworks (MOFs), may hold the key to more efficient and economically viable separation methods. This work proposes to prove the applicability of the multi-component potential theory of adsorption (MPTA) to a real world natural gas adsorbent system to properly characterize the adsorbent’s selectivity for an individual gas component using only the single component isotherms. Thus, the real-world gas separation/purification application of a specific adsorbent for a given gas stream can be obtained simply and effectively without the need for large experimental efforts or costly system modifications until after an initial computational screening of perspective materials has been completed. While the current research effort will use natural gas, which is the world’s largest industrial gas separations application, to validate the MPTA, the tools gained through this effort can be applied to other gas separation effort.
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Häßner, R., W. Theobald, R. Sauerbrey, D. Altenbernd, U. Teubner, E. Forster, T. Wilhein, B. Niemann i G. Schmahl. "Absolute measurement of the spectral brilliance of a subpicosecond UV-laser induced soft x-ray source". W Applications of High Field and Short Wavelength Sources. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/hfsw.1997.the31.
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We have investigated the spectral brilliance of subpicosecond UV-laser-plasmas as a source for the soft x-ray microscopy in the so-called ‘water-window’. The spectral range between the absorption K-edges of carbon (4.36 nm) and oxygen (2.32 nm) is termed ‘water-window’ . The absorption coefficient of both materials differ by one order of magnitude providing a high contrast of the biological samples in their natural environment [1].
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Truitt, Andrew, i S. Nima Mahmoodi. "Piezoelectric Energy Harvesting Through Fluid Excitation". W ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8000.
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Piezoelectric energy harvesters have recently captured a lot of attention in research and technology. They employ the piezoelectric effect, which is the separation of charge within a material as a result of an applied strain, to turn what would otherwise be wasted energy into usable energy. This energy can then be used to support remote sensing systems, batteries, and other types of wireless MEMS devices. Such self powered systems are particularly attractive where hardwiring may not be feasible or numerous battery sources unreasonable. The source of excitation for these systems can include direct actuation, natural or mechanical vibrations, or fluid energy (aerodynamic or hydrodynamic). Fluid based energy harvesting is increasingly pursued due to the ubiquitous nature of the excitation source as well as the strong correlation with other types of excitation. Vortex-induced vibrations as well as vibrations induced by bluff bodies have been investigated to determine potential gains. The shape and size of these bluff bodies has been modeled in order to achieve the maxim power potential of the system. Other studies have focused on aeroelastic fluttering which relies on the natural frequency of two structural modes being achieved through aerodynamic forces. Rather than a single degree of freedom, as seen in the VIV approach, aeroelastic flutter requires two degrees of freedom to induce its vibrational state. This has been modeled through a wing section attached to a cantilevered beam via a revolute joint. To accurately model the behavior of these systems several types of dampening must be considered. Fluid flow excitation introduces the component of dampening via fluid dynamics in addition to structural dampening and electrical dampening from the piezoelectrics themselves. Air flow speed modifies the aerodynamic dampening and it has been shown that at the flutterer boundary the aerodynamic dampening dissipates while the oscillations remain. However, such a system state exhibits a decaying power output due to the shunt dampening effect of the power generation itself. Research in energy harvesting is quickly progressing but much has yet to be discovered. The focus of this paper will be fluid as a source of excitation and the development that has followed thus far. Configurations and applications of previous works will be examined followed by suggestions of new research works to move forward in the field.
Raporty organizacyjne na temat "Natural source materials"
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Suir, Glenn, i Jacob Berkowitz. Inundation depth and duration impacts on wetland soils and vegetation : state of knowledge. Engineer Research and Development Center (U.S.), wrzesień 2021. http://dx.doi.org/10.21079/11681/42146.
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The following synthesizes studies investigating plant and soil responses to increased inundation in order to support ecosystem restoration efforts related to the alteration of natural wetland hydrodynamics. Specific topics include hydrologic regimes, soil response to inundation, and implications for vegetation communities exposed to increased water depths. Results highlight the important interactions between water, soils, and vegetation that determine the trajectory and fate of wetland ecosystems, including the development of feedback loops related to marsh degradation and subsidence. This report then discusses the knowledge gaps related to implications of inundation depth, timing, and duration within an ecosystem restoration context, identifying opportunities for future research while providing source materials for practitioners developing restoration projects.
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Breitbarth, Marco, Anja Hentschel i Simon Kaser. Kunststoffeinträge von Kunstrasenplätzen in Entwässerungssystem - Aufkommen, Rahmenbedingungen und Möglichkeiten der Eintragsminderung. Sonderforschungsgruppe Institutionenanalyse, 2022. http://dx.doi.org/10.46850/sofia.9783941627994.
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Plastics as an environmental problem have been in the focus of science, politics and the public for a long time. Various sources and pathways have already been identified and a wide range of measures have been developed to reduce and, if possible, avoid inputs into the environment. Artificial grass pitches represent a special source of plastic inputs into the environment. Artificial grass with different infill materials has been widely used for some time now on surfaces for a wide range of sports, both amateur and professional. It is characterised by various advantages over natural grass. However, the use of artificial grass on sports surfaces also has its downsides, especially for the environment. On the one hand, the synthetic grass fibres themselves, which become detached through wear, are problematic. On the other hand, synthetic granulate is used as infill material on these pitches to reduce the risk of injury to players, to support the blades of artificial grass and to improve the playing characteristics of the field. However, this granulate can enter the environment in various ways - indirectly via drainage systems or directly. The following comments reflect research results from the InRePlast project. In the following chapter 2, the results of our own investigations on the topic are presented. In Chapter 3, these are compared to other publications and evaluated with regard to their significance. Chapter 4 is devoted to technical and organisational measures to reduce discharges as well as legal approaches to regulation. Finally, Chapter 5 draws a conclusion. Among other things, the study concludes that artificial grass pitches are less relevant as a specific source of plastic inputs than previously discussed. It should also be noted that the input into drainage systems via the collection of dirty water has a significantly higher relevance than the input via the collection of precipitation at the edge of the pitch and that measures should therefore focus on the carry-over on players' clothing and shoes.
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Tan, Peng, i Nicholas Sitar. Parallel Level-Set DEM (LS-DEM) Development and Application to the Study of Deformation and Flow of Granular Media. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, marzec 2023. http://dx.doi.org/10.55461/kmiz5819.
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We present a systematic investigation of computational approaches to the modeling of granular materials. Granular materials are ubiquitous in everyday life and in a variety of engineering and industrial applications. Despite the apparent simplicity of the laws governing particle-scale interactions, predicting the continuum mechanical response of granular materials still poses extraordinary challenges. This is largely due to the complex history dependence resulting from continuous rearrangement of the microstructure of granular material, as well as the mechanical interlocking due to grain morphology and surface roughness. X-Ray Computed Tomography (XRCT) is used to characterize the grain morphology and the fabric of the granular media, naturally deposited sand in this study. The Level-Set based Discrete Element Method (LS-DEM) is then used to bridge the granular behavior gap between the micro and macro scale. The LS-DEM establishes a one-to-one correspondence between granular objects and numerical avatars and captures the details of grain morphology and surface roughness. However, the high-fidelity representation significantly increases the demands on computational resources. To this end a parallel version of LS-DEM is introduced to significantly decrease the computational demands. The code employs a binning algorithm, which reduces the search complexity of contact detection from O(n2) to O(n), and a domain decomposition strategy is used to elicit parallel computing in a memory- and communication-efficient manner. The parallel implementation shows good scalability and efficiency. High fidelity LS avatars obtained from XRCT images of naturally deposited sand are then used to replicate the results of triaxial tests using the new, parallel LS-DEM code. The result show that both micro- and macro-mechanical behavior of natural material is well captured and is consistent with experimental data, confirming experimental observation that the primary source of peak strength of sand is the mechanical interlocking between irregularly shaped grains. Specifically, triaxial test simulations with a flexible membrane produce a very good match to experimentally observed relationships between deviatoric stress and mobilized friction angle for naturally deposited sand. We then explore the viability of modeling dynamic problems with a new formulation of an impulse based LS-DEM. The new formulation is stable, fast, and energy conservative. However, it can be numerically stiff when the assembly has substantial mass differences between particles. We also demonstrate the feasibility of modeling deformable structures in the rigid body framework and propose several enhancements to improve the convergence of collision resolution, including a hybrid time integration scheme to separately handle at rest contacts and dynamic collisions. Finally, we extend the impulse-based LS-DEM to include arbitrarily shaped topographic surfaces and exploit its algorithmic advantages to demonstrate the feasibility of modeling realistic behavior of granular flows. The novel formulation significantly improves performance of dynamic simulations by allowing larger time steps, which is advantageous for observing the full development of physical phenomena such as rock avalanches, which we present as an illustrative example.
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Poverenov, Elena, Tara McHugh i Victor Rodov. Waste to Worth: Active antimicrobial and health-beneficial food coating from byproducts of mushroom industry. United States Department of Agriculture, styczeń 2014. http://dx.doi.org/10.32747/2014.7600015.bard.
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Background. In this proposal we suggest developing a common solution for three seemingly unrelated acute problems: (1) improving sustainability of fast-growing mushroom industry producing worldwide millions of tons of underutilized leftovers; (2) alleviating the epidemic of vitamin D deficiency adversely affecting the public health in both countries and in other regions; (3) reducing spoilage of perishable fruit and vegetable products leading to food wastage. Based on our previous experience we propose utilizing appropriately processed mushroom byproducts as a source of two valuable bioactive materials: antimicrobial and wholesome polysaccharide chitosan and health-strengthening nutrient ergocalciferol⁽ᵛⁱᵗᵃᵐⁱⁿ ᴰ2⁾. ᴬᵈᵈⁱᵗⁱᵒⁿᵃˡ ᵇᵉⁿᵉᶠⁱᵗ ᵒᶠ ᵗʰᵉˢᵉ ᵐᵃᵗᵉʳⁱᵃˡˢ ⁱˢ ᵗʰᵉⁱʳ ᵒʳⁱᵍⁱⁿ ᶠʳᵒᵐ ⁿᵒⁿ⁻ᵃⁿⁱᵐᵃˡ ᶠᵒᵒᵈ⁻ᵍʳᵃᵈᵉ source. We proposed using chitosan and vitamin D as ingredients in active edible coatings on two model foods: highly perishable fresh-cut melon and less perishable health bars. Objectives and work program. The general aim of the project is improving storability, safety and health value of foods by developing and applying a novel active edible coating based on utilization of mushroom industry leftovers. The work plan includes the following tasks: (a) optimizing the UV-B treatment of mushroom leftover stalks to enrich them with vitamin D without compromising chitosan quality - Done; (b) developing effective extraction procedures to yield chitosan and vitamin D from the stalks - Done; (c) utilizing LbL approach to prepare fungal chitosan-based edible coatings with optimal properties - Done; (d) enrichment of the coating matrix with fungal vitamin D utilizing molecular encapsulation and nano-encapsulation approaches - Done, it was found that no encapsulation methods are needed to enrich chitosan matrix with vitamin D; (e) testing the performance of the coating for controlling spoilage of fresh cut melons - Done; (f) testing the performance of the coating for nutritional enhancement and quality preservation of heath bars - Done. Achievements. In this study numerous results were achieved. Mushroom waste, leftover stalks, was treated ʷⁱᵗʰ ᵁⱽ⁻ᴮ ˡⁱᵍʰᵗ ᵃⁿᵈ ᵗʳᵉᵃᵗᵐᵉⁿᵗ ⁱⁿᵈᵘᶜᵉˢ ᵃ ᵛᵉʳʸ ʰⁱᵍʰ ᵃᶜᶜᵘᵐᵘˡᵃᵗⁱᵒⁿ ᵒᶠ ᵛⁱᵗᵃᵐⁱⁿ ᴰ2, ᶠᵃʳ ᵉˣᶜᵉᵉᵈⁱⁿᵍ any other dietary vitamin D source. The straightforward vitamin D extraction procedure and ᵃ ˢⁱᵐᵖˡⁱᶠⁱᵉᵈ ᵃⁿᵃˡʸᵗⁱᶜᵃˡ ᵖʳᵒᵗᵒᶜᵒˡ ᶠᵒʳ ᵗⁱᵐᵉ⁻ᵉᶠᶠⁱᶜⁱᵉⁿᵗ ᵈᵉᵗᵉʳᵐⁱⁿᵃᵗⁱᵒⁿ ᵒᶠ ᵗʰᵉ ᵛⁱᵗᵃᵐⁱⁿ ᴰ2 ᶜᵒⁿᵗᵉⁿᵗ suitable for routine product quality control were developed. Concerning the fungal chitosan extraction, new freeze-thawing protocol was developed, tested on three different mushroom sources and compared to the classic protocol. The new protocol resulted in up to 2-fold increase in the obtained chitosan yield, up to 3-fold increase in its deacetylation degree, high whitening index and good antimicrobial activity. The fungal chitosan films enriched with Vitamin D were prepared and compared to the films based on animal origin chitosan demonstrating similar density, porosity and water vapor permeability. Layer-by-layer chitosan-alginate electrostatic deposition was used to coat fruit bars. The coatings helped to preserve the quality and increase the shelf-life of fruit bars, delaying degradation of ascorbic acid and antioxidant capacity loss as well as reducing bar softening. Microbiological analyses also showed a delay in yeast and fungal growth when compared with single layer coatings of fungal or animal chitosan or alginate. Edible coatings were also applied on fresh-cut melons and provided significant improvement of physiological quality (firmness, weight ˡᵒˢˢ⁾, ᵐⁱᶜʳᵒᵇⁱᵃˡ ˢᵃᶠᵉᵗʸ ⁽ᵇᵃᶜᵗᵉʳⁱᵃ, ᵐᵒˡᵈ, ʸᵉᵃˢᵗ⁾, ⁿᵒʳᵐᵃˡ ʳᵉˢᵖⁱʳᵃᵗⁱᵒⁿ ᵖʳᵒᶜᵉˢˢ ⁽Cᴼ2, ᴼ²⁾ ᵃⁿᵈ ᵈⁱᵈ not cause off-flavor (EtOH). It was also found that the performance of edible coating from fungal stalk leftovers does not concede to the chitosan coatings sourced from animal or good quality mushrooms. Implications. The proposal helped attaining triple benefit: valorization of mushroom industry byproducts; improving public health by fortification of food products with vitamin D from natural non-animal source; and reducing food wastage by using shelf- life-extending antimicrobial edible coatings. New observations with scientific impact were found. The program resulted in 5 research papers. Several effective and straightforward procedures that can be adopted by mushroom growers and food industries were developed. BARD Report - Project 4784
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Baldwin, Richard M. TA-97-4 Black Powder in the Gas Industry - Sources Characteristics and Treatment. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), maj 1998. http://dx.doi.org/10.55274/r0011722.
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The original objective of this research was to investigate means of controlling materials ingested into compressors in pipeline, refinery, gathering, and storage services. After an initial industry survey, it was determined that "Black Powder" (various forms of iron sulfide mixed with contaminants) is the least understood and most prominent contamination problem in pipelines and their compression equipment. The information documented in this report was gathered from technical literature, the Internet, researchers, experts, practitioners in the natural gas industry, field experience, and equipment manufacturers' publications. This search has determined that there is much expert knowledge in the technical community concerning many aspects of the iron sulfide problem, however, there is only a limited understanding by those in the gas industry that face the problem. This report discusses information gathered as a part of the research, including a section with references to retrievable literature used.
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Clement, Michael. Engineering With Nature website user guide. Engineer Research and Development Center (U.S.), marzec 2022. http://dx.doi.org/10.21079/11681/43440.
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The Engineering With Nature (EWN) program is a high-profile effort that aims to deliver cost-effective, broadly beneficial solutions to natural re-source and sustainability challenges across the nation. A portion of this is accomplished through the use of the EWN website, which features news, podcasts, articles, and more. The content on the EWN website serves to educate and inform hundreds of visitors monthly. This content is generated and managed by EWN team members with web development experience, as it requires manually editing the website HTML and staging changes on a development server. With the EWN website 2.0, a new website framework (WordPress) has been implemented that will save content managers time and effort by providing a front-end user interface (UI) to enable the uploading, staging, and approval of new content for the website, along with a visual refresh to herald the impending release of season 2 of the EWN Podcast. This document’s purpose is to demonstrate the functionality of the new EWN website and provide instructional material for those managing content via the new EWN website.
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Chefetz, Benny, i Baoshan Xing. Sorption of hydrophobic pesticides to aliphatic components of soil organic matter. United States Department of Agriculture, 2003. http://dx.doi.org/10.32747/2003.7587241.bard.
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Sorption of hydrophobic compounds to aliphatic components of soil organic matter (SOM) is poorly understood even though these aliphatic carbons are a major fraction of SOM. The main source of aliphatic compounds in SOM is above- and below-ground plant cuticular materials (cutin, cutan and suberin). As decomposition proceeds, these aliphatic moieties tend to accumulate in soils. Therefore, if we consider that cuticular material contributes significantly to SOM, we can hypothesize that the cuticular materials play an important role in the sorption processes of hydrophobic compounds (including pesticides) in soils, which has not yet been studied. The overall goal of this research was to illustrate the mechanism and significance of the refractory aliphatic structures of SOM in sorbing hydrophobic compounds (nonionic and weakly polar pesticides). The importance of this study is related to our ability to demonstrate the sorption relationship between key pesticides and an important fraction of SOM. The specific objectives of the project were: (1) To isolate and characterize cuticular fractions from selected plants; (2) To investigate the sorption mechanism of key hydrophobic pesticides and model compounds to cuticular plant materials; (3) To examine the sorption mechanisms at the molecular level using spectroscopic techniques; (4) To investigate the sorption of key hydrophobic pesticides to synthetic polymers; (5) To evaluate the content of cuticular materials in agricultural soils; and (6) To study the effect of incubation of plant cuticular materials in soils on their sorptive capabilities. This project demonstrates the markedly high sorption capacity of various plant cuticular fractions for hydrophobic organic compounds (HOCs) and polar organic pollutants. Both cutin (the main polymer of the cuticle) and cutan biopolymers exhibit high sorption capability even though both sorbents are highly aliphatic in nature. Sorption by plant cuticular matter occurs via hydrophobic interactions and H-bonding interactions with polar sorbates. The cutin biopolymer seems to facilitate reversible and noncompetitive sorption, probably due to its rubbery nature. On the other hand, the epicuticular waxes facilitate enhance desorption in a bi-solute system. These processes are possibly related to phase transition (melting) of the waxes that occur in the presence of high solute loading. Moreover, our data highlight the significance of polarity and accessibility of organic matter in the uptake of nonpolar and polar organic pollutants by regulating the compatibility of sorbate to sorbent. In summary, our data collected in the BARD project suggest that both cutin and cutan play important roles in the sorption of HOCs in soils; however, with decomposition the more condensed structure of the cutin and mainly the cutan biopolymer dominated sorption to the cuticle residues. Since cutin and cutan have been identified as part of SOM and humic substances, it is suggested that retention of HOCs in soils is also controlled by these aliphatic domains and not only by the aromaticrich fractions of SOM.
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Thompson i Anderson. GRl-90-0337 Identification of Injected Storage Gas. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), grudzień 1990. http://dx.doi.org/10.55274/r0011193.
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This project developed and evaluated methods for distinguishing between natural gases from different sources. Identification of particular "batches" of gas can be of considerable importance. For example, means of distinguishing between gases can demonstrate whether a gas appearing at the surface over a storage area is migrating storage gas or is gas formed by bacterial action above the storage zone. As another example, identification methods can allow detection of migration from a storage zone to an adjacent production zone. Two general methods were evaluated/developed in this project; tracers and compositional methods. Relative migration rates of a series of potential tracers were evaluated under a variety of conditions and in varying reservoir materials. Tracers having the best migration characteristics were identified. Potential tracers (either present in natural gas or added) which are not detected by electron capture or flame ionization detectors need improved methods of detection. The discharge ionization detector was evaluated for the detection of argon, carbon dioxide, carbon monoxide, Freon-14 (carbon tetrafluoride), and neon. Two computer programs, based on regression and factor analysis methods, to aid in the identification of gases using compositional analyses, were further developed and improved.
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Lease i Jones. PR-266-12213-R01 Minimizing Gas Compressor Lubricating Oil Consumption. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), marzec 2013. http://dx.doi.org/10.55274/r0010085.
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One of the main sources of fouling in pipelines is related to the use of lubrication (and possibly over-lubrication) in reciprocating compressors. In addition to the obvious cost of lubricants, there are also many hidden costs associated with reciprocating compressor lubrication. Some of these hidden costs include disposal of collected oil, gas storage field contamination, scrubber cleaning, and loss of general pipeline efficiency. Minimizing reciprocating gas compressor lubrication oil consumption can address these costs while at the same time reducing the negative environmental impact associated with reciprocating compressor over-lubrication. One approach to minimize reciprocating compressor lubrication oil consumption is to use non-lubricated reciprocating compressor trim (e.g. filled PTFE composites). This report provides an in-depth evaluation of a wear test program performed on a variety of filled PTFE materials in air and a natural gas environment. This evaluation included comparison of this data to results provided in the open literature. One specific reference used as a comparison performed a comprehensive wear testing program on filled PTFE materials in a variety of gases (including methane) for a variety of dew points. Parameters evaluated in this study included the effect of dew point ranging from +0� C to -100� C, and the effect of various gas environment, including air, methane, propane, ethylene, and nitrogen.
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Khan, Mahreen. The Role of Clans in Moldova in Politics and Economics. Institute of Development Studies, maj 2022. http://dx.doi.org/10.19088/k4d.2022.116.
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Moldova’s politics, economy, justice system and media are increasingly dominated by a powerful group of elites, led by oligarchs - a new breed of businessmen-politicians who have emerged in the past decade - controlling strategic sectors of the economy and finance, hijacking the political system, taming the judiciary and acquiring monopolistic control of mass media, to promote and protect their vast business empires. Alongside traditional clan, kinship and patronage networks these elites exert influence through informal politics , shaping Moldova’s politics and economy, often hindering reforms for democratisation, rule of law, meritocracy and transparency. This helpdesk report looks at the nature and role of clans in Moldova in the country’s politics and economy. This literature review utilises academic as well as grey sources, research papers, media and blogs published mainly in the past ten years. The sources reveal a paucity of Moldova centric material, especially on the sub-issue of clans, but much more literature is available on the role of informal politics and state capture by elites, especially oligarchs, in Moldova. The evidence found did not address gender and disability issues.