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Estudos das propriedades mecânicas e térmicas do polímero biodegradável poli-3-hidroxibutirato (PHB) e de compósitos PHB/pó de madeira.; Study of mechanical and thermal properties of the biodegradable polymer poly-3-hydroxybutyrate (PHB) and PHB/wood flour composites.

Machado, Miriam Lúcia Chiquetto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/06/2008 PT
Relevância na Pesquisa
66.96088%
O objetivo deste trabalho foi o estudo das propriedades mecânicas e térmicas do PHB e de compósitos de PHB/pó de madeira processados, reprocessados e irradiados. Foram preparados compósitos com PHB e pó de madeira com concentrações de PHB/pó de madeira de 90/10, 80/20 e 70/30 (m/m). Foram realizados ensaios de propriedades mecânicas, HDT, ponto de amolecimento Vicat, TGA e DSC. A incorporação do pó de madeira aumentou o grau de cristalinidade e a temperatura de cristalização do polímero, e nos compósitos PHB/pó de madeira 80/20 e 70/30 a rigidez do material aumentou em relação ao polímero puro. O compósito PHB/pó de madeira 70/30 apresentou os melhores resultados em termos econômicos, de processamento e de estabilidade em relação ao reprocessamento. A irradiação após o processamento, em dose de 30 kGy, provocou aumento da rigidez do PHB puro e dos compósitos PHB/pó de madeira 90/10 e 80/20, embora as outras propriedades tenham decrescido. O compósito PHB/pó de madeira 70/30 apresentou queda de todas as propriedades com a irradiação.; The purpose of this work was the study of the mechanical and thermal properties of processed, reprocessed and irradiated PHB, as well as PHB/wood flour composites. PHB/wood flour composites were prepared with PHB/wood relation of 90/10...

Thermal properties of passion fruit juice as affected by temperature and water content

Gratão, Ana Carolina Amaral; Silveira Jr., Vivaldo; Polizelli, Marcos Alexandre; Telis-Romero, Javier
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 413-431
ENG
Relevância na Pesquisa
67.06517%
The specific heat, thermal conductivity and density of passion fruit juice were experimentally determined from 0.506 to 0.902 (wet basis) water content and temperatures from 0.4 to 68.8C. The experimental results were compared with existing and widely used models for the thermal properties. In addition, based on empiric equations from literature, new simple models were parameterized with a subset of the total experimental data. The specific heat and thermal conductivity showed linear dependency on water content and temperature, while the density was nonlinearly related to water content. The generalized predictive models were considerably good for this product but the empiric, product-specific models developed in the present work yield better predictions. Even though the existing models showed a moderate accuracy, the new simple ones would be preferred, because they constitute an easier and direct way of evaluating the thermal properties of passion fruit juice, requiring no information about the chemical composition of the product, and a reduced time of the estimation procedure, as the new empiric models are described in terms of only two physical parameters, the water content and the temperature. © Copyright 2005, Blackwell Publishing All Rights Reserved.

O estudo do efeito de dois modos de fotopolimerização nas propriedades mecanicas e termicas de duas marcas de resinas dentais comerciais; The study of the effect in two types of photopolymerization in the mechanical and thermal properties of two commercial dental resins

Fabiana Andrade Moreira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/02/2005 PT
Relevância na Pesquisa
67.131245%
As resinas compostas vêm sendo desenvolvidas para o mercado odontológico desde a segunda metade do século passado, devendo atender a uma série de requisitos necessários para o bom desempenho da restauração. Isto pode ser conseguido através da variação da composição das resinas compostas, em relação aos monômeros que compõem a matriz polimérica e as cargas inorgânicas, como também de parâmetros relacionados ao aparelho fotopolimerizador, tais como intensidade e tipo de fonte. Os objetivos desta pesquisa foram avaliar a influência causada nas propriedades mecânicas e térmicas, de duas resinas comercias, Z100(3M) e Charisma (Heraues Kulzer). Bem como, a influência do tipo de fotopolimerizador, utilizando fontes do tipo luz halógena e diodo emissor de luz, LED. As avaliações foram realizadas por análise termodinâmico mecânica, DMA e calorimetria diferencial exploratória, DSC. Um planejamento fatorial 22 (2 variáveis 2 níveis cada variável) foi utilizado para analisar os resultados. As variáveis foram resina comercial e aparelho fotopolimerizador, sendo os níveis para a primeira as resinas Z100e Charisma, e para a segunda, os níveis foram os fotopolimerizadores tipo LED e tipo luz halógena. As duas resinas apresentaram diferentes propriedades mecânicas e térmicas. Além disso o tipo de aparelho fotopolimerizador também influenciou os resultado. As resinas fotopolimerizadas por luz halógena apresentaram melhores propriedades mecânicas e térmicas. Pôde-se observar que a resina Charisma apresentou cura térmica no decorrer das duas análises. Esta mesma resina obteve o melhor desempenho no DMA provavelmente por ser susceptível a pós cura; The resins composite have been developed to dentistry purposes since the second half of the last century. The research of these materials must take into account a serie of requirements that further a suitable performance to the restoration. Due to the resins composite are submitted to the oral environment...

Cork–polymer biocomposites: mechanical, structural and thermal properties

Fernandes, E. M.; Correlo, V. M.; Mano, J. F.; Reis, R. L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2015 ENG
Relevância na Pesquisa
66.857456%
This work addresses to the preparation of biocomposites resulting from the combination of different biodegradable aliphatic polyesters with cork (30 wt.%). The lignocellulosic biomass with closed cellular structure was compounded with poly(L-lactic acid) (PLLA), polyhydroxybutyrate-co-hydroxyvalerate (PHBV), poly-ε-caprolactone (PCL) and starch-poly-ε-caprolactone (SPCL) blend using a twin-screw extruder prior to injection moulding into tensile samples. The physico-mechanical and thermal properties of the matrices and the bio-based cork composites were investigated. This study shows that the addition of cork contributes to produce lightweight materials using PLLA and PHBV matrices and promotes an increase on the stiffness of PCL. The fracture morphology observations showed good physical corkâ matrix bonding with absence of voids or cavities between cork and the bio-based polyesters. Cork increases the crystallinity degree of the biocomposites. These findings suggest that the corkâ polymer biocomposites are a viable alternative to develop more sustainable composite materials, such as automotive interior parts and bio-based caps for wine bottles as it has been shown as proof-of-concept.

Influence of different finishing treatments over mechanical and thermal properties of bed linen

Vidrago, C.; Abreu, Maria José; Soares, Graça M. B.
Fonte: The Fiber Society Publicador: The Fiber Society
Tipo: Conferência ou Objeto de Conferência
Publicado em /05/2012 ENG
Relevância na Pesquisa
67.10095%
This work aims to assess the relationship between the mechanical and the thermal properties of summer bed linen using different softener formulations in home textiles finishing. Objectively, we intend to study the effect of different softeners and their concentrations, based on non-ionic polyethylene dispersions and a cationic silicone softener micro-emulsion on textile properties. The research shown that thermal related properties are influenced by polyethylene softeners, while the silicone softener influences the mechanical behavior of the tested samples. Finally, selected softened samples of bed linen were evaluated by a dry thermal manikin to validate some conclusions.

On the Use of Thermal Properties for Characterizing Dimension Stones

Amaral, Paulo; Correia, António; Lopes, Luis; Rebola, Paula; Pinho, António; Lopes, José Carrilho
Fonte: Valorpedra, Associação/Cluster da Pedra Natural Publicador: Valorpedra, Associação/Cluster da Pedra Natural
Tipo: Aula
POR
Relevância na Pesquisa
67.30936%
The use of dimension stones in architecture and civil engineering implies the knowledge of several mechanical, physical and chemical properties. Even though it has been usual practice to measure physical and mechanical properties of dimension stones the same is not true for thermal properties, such as thermal conductivity, thermal diffusivity, specific heat capacity, and heat production. These properties are particularly important when processes related with heating and cooling of buildings must be considered.Thermal conductivity, thermal diffusivity, and specific heat capacity are related with the way thermal energy is transmitted and accumulated in stones; heat production has to do with the amount of radioactive elements on the rocks and so with the environmental impact of radioactivity and public health problems. It is important to start to measure on a routine basis those four thermal properties in rocks and, in particular, in dimension rocks so that their application can be improved and optimized. With this is mind three sets of different rock types (granites, limestones, and marbles) were collected to measure the thermal conductivity, the thermal diffusivity, and the specific heat capacity with the objective of characterizing them in terms of those properties. Since the same set of rocks has also been studied for other physical properties...

On the Use of Thermal Properties for Characterizing Dimension Stones

Amaral, Paulo; Correia, António; Lopes, Luís; Rebola, Paula; Pinho, António; Lopes, José Carrilho
Fonte: Trans Tech Publications, Switzerland Publicador: Trans Tech Publications, Switzerland
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.306724%
The use of dimension stones in architecture and civil engineering implies the knowledge of several mechanical, physical, and chemical properties. Even though it has been usual practice to measure physical and mechanical properties of dimension stones the same is not true for thermal properties such as thermal conductivity, thermal diffusivity, specific heat capacity, and heat production. These properties are particularly important when processes related with heating and cooling of buildings must be considered. Thermal conductivity, thermal diffusivity, and specific heat capacity are related with the way thermal energy is transmitted and accumulated in stones; heat production has to do with the amount of radioactive elements in the rocks and so with the environmental impact of radioactivity and public health problems. It is important to start to measure on a routine basis those four thermal properties in rocks and, in particular, in dimension rocks so that their application can be improved and optimized. With this is mind three sets of different rock types (granites, limestones, and marbles) were collected to measure the thermal conductivity, the thermal diffusivity, and the specific heat capacity with the objective of characterizing them in terms of those properties. Since the same set of rocks has also been studied for other physical properties...

On the Use of Thermal Properties for Characterizing Dimension Stones

Amaral, Paulo; Correia, António; Lopes, Luís; Rebola, Paula; Pinho, António; Lopes, José Carrilho
Fonte: Trans Tech Publications, Switzerland Publicador: Trans Tech Publications, Switzerland
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.306724%
The use of dimension stones in architecture and civil engineering implies the knowledge of several mechanical, physical, and chemical properties. Even though it has been usual practice to measure physical and mechanical properties of dimension stones the same is not true for thermal properties such as thermal conductivity, thermal diffusivity, specific heat capacity, and heat production. These properties are particularly important when processes related with heating and cooling of buildings must be considered. Thermal conductivity, thermal diffusivity, and specific heat capacity are related with the way thermal energy is transmitted and accumulated in stones; heat production has to do with the amount of radioactive elements in the rocks and so with the environmental impact of radioactivity and public health problems. It is important to start to measure on a routine basis those four thermal properties in rocks and, in particular, in dimension rocks so that their application can be improved and optimized. With this is mind three sets of different rock types (granites, limestones, and marbles) were collected to measure the thermal conductivity, the thermal diffusivity, and the specific heat capacity with the objective of characterizing them in terms of those properties. Since the same set of rocks has also been studied for other physical properties...

On the use of thermal properties for characterizing dimension stones from Portugal

Correia, A.; Lopes, Luís; Rebola, Paula
Fonte: ARBER Professional Congress Services Publicador: ARBER Professional Congress Services
Tipo: Aula
POR
Relevância na Pesquisa
67.17929%
It has been usual practice to measure physical and mechanical properties of dimension stones; however, the same is not true for thermal properties, such as thermal conductivity, thermal diffusivity, specific heat capacity, and heat production which are particularly important when processes related with heating and cooling of buildings must be considered. Thermal conductivity, thermal diffusivity, and specific heat capacity are related with the way thermal energy is transmitted and accumulated in stones; heat production is related with the amount of radioactive elements on the rocks. Several rock samples from several quarries were collected in Mainland Portugal for measuring their thermal conductivities, thermal diffusivities, specific heat capacities, and heat productions. The rock set consists of granites, limestones, and marbles used in architecture and civil engineering. The results of the study indicate that the collected granites have thermal conductivities, thermal diffusivities, and specific heat capacity that vary from 2.98 ± 0.09 to 3.24 ± 0.21 W/m.K, 1.32 ± 0.03 to 1.55 ± 0.12 (x10-6) m2/s, 2.10 ± 0.04 to 2.26 ± 0.04 J/m3.K, respectively; the collected limestones have thermal conductivities, thermal diffusivities...

Effect of synthetic mica on the thermal properties of poly(lactic acid)

Souza,Diego Holanda Saboya; Andrade,Cristina Trist‹o; Dias,Marcos Lopes
Fonte: Associação Brasileira de Polímeros Publicador: Associação Brasileira de Polímeros
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
Relevância na Pesquisa
66.882705%
Poly(lactic acid)/Somasif fluoromica nanocomposites were prepared by melt blending and their thermal properties investigated by DSC, TGA and DMA. Three different types of synthetic mica (Somasif ME-100, Somasif MAE and Somasif MPE) were used at different contents (2.5, 5.0 and 7.5 wt %). The melt blending of PLA and these micas is characterized by a considerable reduction in the matrix molecular weight, which decreases when the nanofiller content is increased. For all nanocomposites, the thermal stability increases when mica is added to the polymer, with the Somasif MPE, producing the highest increase of the degradation temperature and highest reduction of Tg.

Desenvolvimento do método de aquecimento plano parcial para a determinação simultânea de propriedades térmicas sem o uso de transdutores de fluxo de calor; Development of the Part Heat Plate Method to Estimate Simultaneously Thermal Properties without Heat Flux Transducer

Borges, Valério Luiz
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Tese de Doutorado
POR
Relevância na Pesquisa
67.08004%
Desenvolve-se, neste trabalho, uma técnica experimental que permite a obtenção da difusividade e da condutividade térmica de materiais condutores e não condutores através do uso de elementos de aquecimento e de técnicas de estimativas de funções para a obtenção do fluxo de calor imposto. O princípio básico do procedimento é dividido em: i) desenvolvimento de um aparato experimental que permite a imposição do fluxo de calor em uma parte da amostra enquanto as superfícies remanescentes permanecem isoladas do meio; ii) obtenção de um modelo térmico deste aparato; iii) obtenção de uma grandeza proporcional ao fluxo de calor imposto na amostra, Q+(t), usando a técnicas de problemas inversos; iv) obtenção da difusividade térmica; v) comparação entre a taxa de calor total fornecida pelo elemento de aquecimento e a grandeza proporcional ao fluxo de calor imposto na amostra durante o ciclo de aquecimento e a conseqüente obtenção da condutividade térmica. A flexibilidade da técnica proposta inclui a medição de materiais sólidos metálicos e não metálicos com geometrias variáveis. Nesse sentido, apresenta-se a montagem e o planejamento experimental bem como os resultados do trabalho para a determinação das propriedades térmicas de três tipos diferentes de materiais (aço inox 304...

Determinação simultânea da condutividade térmica e da difusividade térmica variando com a temperatura; Identification of yemperature - dependent simultaneous thermal properties of Polyvinyl Chloride (PVC)

Tillmann, Amanda Ribeiro
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Dissertação
POR
Relevância na Pesquisa
67.121904%
Propõe-se nesse trabalho uma técnica experimental para obtenção simultânea da difusividade térmica, α, e condutividade térmica, λ, variando com a temperatura de materiais isolantes. O modelo térmico usado considera a transferência de calor unidimensional em um meio submetido a um fluxo de calor transiente na superfície frontal e isolado na superfície oposta. A determinação simultânea dessas propriedades variando com a temperatura é feita usando-se o princípio da técnica Mista. Nessa técnica são definidas duas funções objetivo, uma no domínio da freqüência e outra no domínio do tempo. Uma das funções é calculada a partir da fase da função resposta em freqüência de um sistema dinâmico que tem como entrada o fluxo de calor e saída a temperatura em um modelo unidimensional. A segunda função objetivo é obtida usando os sinais de temperatura na superfície frontal e oposta ao aquecimento. Obtêm-se as propriedades α e λ variando com a temperatura para amostra de PVC (Policloreto de Vinila) a partir de uma montagem experimental. A montagem consiste basicamente de um forno com temperatura controlada. As propriedades α e λ foram determinadas para 7 (sete) pontos de temperaturas médias, nas faixas de 20ºC a 66ºC. As propriedades são estimadas a partir da imposição de um fluxo de calor que estabelece uma diferença de temperatura máxima entre as superfícies da amostra de 4...

Monitoring near-surface thermal properties in conjunction with energy and moisture budgets to facilitate the optimization of ground-source heat pumps in the glaciated Midwest

Naylor, Shawn; Gustin, Andrew R.; Ellett, Kevin M.
Fonte: Universidade de Indiana Publicador: Universidade de Indiana
Tipo: Conferência ou Objeto de Conferência
EN_US
Relevância na Pesquisa
67.18615%
This poster was presented at the American Geophysical Union Fall Meeting 2011, San Francisco, Calif., on December 7, 2011. It was part of IN33C, Geothermal energy research and discovery II posters session.; By exploiting the near-surface heat reservoir, ground-source heat pumps (GSHP) represent an important renewable energy technology that can be further developed by establishing data sets related to shallow (<100m) thermal regimes. Although computer programs are available for GSHP installers to calculate optimal lengths and configurations of ground-coupling geothermal systems, uncertainties exist for input parameters that must first be determined for these models. Input parameters include earth temperatures and thermal properties of unconsolidated materials. Furthermore, thermal conductivity of sediments varies significantly depending on texture and moisture content, highlighting the need to characterize various unconsolidated materials under varying soil moisture regimes. Regolith texture data can be, and often are, collected for particular installations, and are then used to estimate thermal properties for system design. However, soil moisture and temperature gradients within the vadose zone are rarely considered because of the difficulty associated with collecting a sufficient amount of data to determine predominant moisture and temperature ranges. Six monitoring locations were chosen in Indiana to represent unique hydrogeologic settings and near-surface glacial sediments. The monitoring approach includes excavating trenches to a depth of 2 meters (a typical depth for horizontal GSHP installations) and collecting sediment samples at 0.3-meter intervals to determine thermal conductivity...

Investigation of Soil for Shallow Geothermal: field tests and laboratory measurements for the determination of thermal properties for the design of combined abstraction of heat and storage of solar energy

Alberdi Pagola, María
Fonte: Universidade de Cantabria Publicador: Universidade de Cantabria
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
66.97824%
Soil thermal properties determination for shallow geothermal systems is vital since they constrain the design and optimisation of the system for either heat extraction or storing airos. Hence, the testing of the ground becomes an important aspect. This subsoil understanding can be achieved by literature estimations, laboratory tests, in-situ tests and numerical simulations. VIA University College owns in its facilities three100m depth different BHE (Single U, Double U and Coaxial) and the equipment to execute thermal conductivity measurements in the laboratory and in-situ TRT. So, in this dissertation a three way approach to the obtaining of the ground thermal conductivity has been executed: i) a priori estimation from literature; ii) laboratory test using the Thermal Needle Probe Procedure and iii) in-situ TRT. The results have been compared. In addition, from the TRT the borehole resistance can be calculated and an evaluation of the three BHE has been made.; Máster europeo en Ingeniería de la Construcción

Srub suits vs clean air suits: a thermal properties comparison

Abreu, Isabel; Ribeiro, Patrícia; Abreu, Maria José
Fonte: University of Zagreb, Faculty of Textile Technology, Zagreb, Croatia Publicador: University of Zagreb, Faculty of Textile Technology, Zagreb, Croatia
Tipo: Conferência ou Objeto de Conferência
Publicado em 01/10/2014 ENG
Relevância na Pesquisa
67.088877%
In operationg room (OR), the health professionals are exposed to stress situations that can influence their physical and psychological performance. The thermal properties are an important requirement for the best performance of OR medical clothing, that plays a crucial role in thermal comfort of the user, that involve the regulation of heat and mass transfer between a clothed body and the environment. In this way, the aim of this work was comparison of thermal properties between scrub and clean air suits. The test was performed on a thermal manikin and Alambeta to measure clothing insulation and to evaluate the thermal comfort. These tests provide a good estimate of the total dry heat loss from the body and the distribution of heat flow between body surface and textile materials.; The financial funding from QREN, POFC, Vale Inovação Project Nº 2012/24228 is also gratefully acknowledged.

Improving the thermal properties of fluoroelastomer (Viton GF-600S) using acidic surface modified carbon nanotube

Heidarian,Javad; Hassan,Aziz; Rahman,Nor Mas Mira Abd
Fonte: Associação Brasileira de Polímeros Publicador: Associação Brasileira de Polímeros
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 EN
Relevância na Pesquisa
66.93818%
AbstractAcid surface modified carbon nanotube (MCNT)-, Carbon nanotube (CNT)-filled fluoroelastomer (FE) and unfilled-FE were prepared (MCNT/FE, CNT/FE and FE). The compounds were subjected to thermogravimetric analysis (TGA) and heat air aging, and characterized by Energy Dispersive X-Ray (EDX). Results showed that MCNT improved the thermal properties of FE, resulting in a larger amount of FE and char remaining in the temperature range of 400-900 °C relative to unfilled FE and CNT/FE. The MCNT/FE TGA curve shifted towards higher temperatures compared to CNT/FE and FE. The same results also revealed that higher percentages of FE were undegraded or less degraded especially near MCNT in the temperature range of 400-540 °C. Energy Dispersive X-Ray (EDX) results indicated that the percentage of carbon and fluorine in the residue of TGA scans, up to 560 °C, of MCNT/FE were the same as CNT/FE, and were higher than FE. EDX results of TGA residue (run up to 900 °C) showed that most of the undegraded FE, which was not degraded at temperatures below 560 °C, was degraded from 560 °C to 900 °C in both MCNT/FE and CNT/FE, with the char in MCNT/FE being more than that in CNT/FE. EDX analysis of thermal aged specimens under air showed that...

Experimental investigation of the mechanical micro structural and thermal properties of thin CrAIN layers deposited by PVD technique for various aluminum percentages

GHRIB, Taher; TLILI, Brahim; NOUVEAU, Corinne; BENLATRECHE, Yacine; LAMBERTIN, Michel; YACOUBI, Noureddine; ENNASRI, M.
Fonte: Elsevier Publicador: Elsevier
EN
Relevância na Pesquisa
67.00542%
The thin film of chromium nitride and their derivatives obtained by the filing process physical vapor deposition attract more and more attention from industry given their high resistance to wear. This quality of these coatings may be linked to their good mechanical and tribological properties. Several experimental investigations have led to the development of CrAlN (Chronium Aluminum Nitride) hard coatings by varying the aluminum target bias voltage, in preference to the traditional CrN coating. The present work is based on the investigation of physical and mechanical properties of CrAlN coating deposited on a silicon substrate and the effect of the aluminum proportion on their variation. The results demonstrate that variation in aluminum proportion alters the resulting columnar morphology, porosity and the thermal properties. The correlation between aluminum proportions in CrAlN coatings and his thermal properties revealed that the conductivity and the diffusivity are influenced primarily by size and shape distribution of the pores and secondarily by decrease of the stitch parameter dimension.

Revisiting the crystal structure and thermal properties of NaMgAl(oxalate) sub>3 •9H 2 O/Cr(III): an extraordinary spectral hole-burning material

Riesen, Hans; Rae, A David
Fonte: Royal Society of Chemistry Publicador: Royal Society of Chemistry
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.93934%
We have reinvestigated the crystal structure and thermal properties of NaMgAl(oxalate)3•9H2O. In the thermal gravimetric analysis the steps of dehydration and decomposition/oxidation yield a mass change that is commensurate with 9 water molecules of hyd

Particle size effect on mechanical and thermal properties of SiO2 particulate polymer composites

Jang, Jaesoon
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
67.033184%
Suhr, Jonghwan; The objective of this thesis is to investigate the effect of the particle size on mechanical and thermal properties of both micro- and nano sized SiO2 particulate composites over a wide range of particle volume fractions. In this study, spherically shaped 10μm and 20nm SiO2 particles, and diglycidyl ether of bisphenol A (DGEBA) are used as fillers and as matrix material, respectively. While 10μm SiO2 particles are dispersed in the epoxy through a direct shear mixing method, nano-composites are fabricated by using commercially available standard Nanopox F400 (nanoresins AG, Germany) with hardener (Albidur HE600) at desirable volume fractions up to 15vol%. All samples were examined for cure degree and particle dispersion quality by the use of differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) or transmission electron microscopy (TEM), respectively. The glass transition temperature of samples was identified by DSC and mechanical dynamic analysis (DMA). Using thermal mechanical analysis (TMA), the thermal stability of the samples was evaluated. This study also employs tensile and fracture testing to characterize the tensile properties including Young’s modulus (E), tensile toughness, and fracture toughness (KIC). In the test results...

Chemical and thermal properties of VIP latrine sludge

Zuma,Lungi; Velkushanova,Konstantina; Buckley,Chris
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2015 EN
Relevância na Pesquisa
67.10095%
This study investigated the chemical and thermal properties of faecal sludge from 10 dry VIP latrines in Bester's Camp in the eThekwini Municipality, Durban, South Africa. Faecal sludge samples were selected at different depths and from the front and back sections of 10 VIP latrines during a manual emptying process. The samples were analysed for: moisture content; volatile solids; chemical oxygen demand; ammonia; total Kjeldahl nitrogen; pH; orthophosphate; thermal conductivity; calorific value and heat capacity. These properties will facilitate the design of faecal sludge emptying and treatment equipment. A manual sorting of the pit contents was carried out to determine the categories and amounts of household waste present. There was a significant difference in the moisture, volatile solids, chemical oxygen demand, ammonia, total Kjeldahl nitrogen and orthophosphate content of the faecal sludge between the front and back sections of the pit. There was minimal change in the thermal properties within the pit. The median values through the pit of each property analysed were: moisture content - 0.81 g water/g wet mass; volatile solids - 1.5 g VS/g ash; COD - 1.7 g COD/g ash; ammonia nitrogen - 10 mg NH3-N/g dry mass; TKN - 39 mg N/g dry mass; pH - 8.03; orthophosphate - 0.06 mg PO4/g dry mass; thermal conductivity - 0.55 W/m K; calorific value - 14 kJ/g dry mass; heat capacity - 2.4x10³ kJ/kg K. On average...