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Durability of green concrete as a structural material /Abbas, Abdelgadir Ahmed, January 1900 (has links)
Thesis (Ph.D.) - Carleton University, 2007. / Includes bibliographical references (p. 317-325). Also available in electronic format on the Internet.
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Optical gradation for crushed limestone aggregatesCheng, Ken, January 2000 (has links)
Thesis (Ph. D.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains x, 179 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 149-153).
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Determination of aggregate shape properties using X-ray tomographic methods and the effect of shape on concrete rheologyErdoğan, Sinan Turhan, Fowler, David W. Garboczi, Edward J. January 2005 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisors: David W. Fowler and Edward J. Garboczi. Vita. Includes bibliographical references.
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Experimental assessment of aggregatesTrimble, Nicholas Robert. January 2007 (has links) (PDF)
Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Robert L. Mokwa. Includes bibliographical references (leaves 89-91).
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RESILIENT MODULUS OF RECYCLED AGGREGATES AS ROAD PAVEMENT MATERIALSSingh, Pralendra 01 May 2015 (has links)
The sources of natural or virgin coarse aggregates are diminishing in alarming rate and its production is quite expensive, uses a lot of energy, and is not environmental friendly. Hence, utilizing the recycled aggregates like reclaimed or recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP) on road pavement will not only preserve the natural aggregates but also reduce the negative environmental impact. It also helps to conserve the waste landfill sites. The major downside for the use of the recycled aggregate is the quality control during its production. This research characterizes RCA samples obtained from a demolished old foundation and RAP samples from old parking lot and determines their suitability as road pavement materials. Virgin aggregates, recycled aggregates, and several blended mixtures with 20 to 80% replacement of natural coarse aggregate or virgin aggregate (NCA or VA) by weight with RCA and RAP were prepared and tested for resilient modulus (Mr) and California Bearing Ratio (CBR) test. The durability of the virgin aggregate and recycled aggregate were also determined by micro-deval test. The resilient modulus value of 100% RCA and 100% VA was found to be very similar or higher but for 100% RAP the resilient modulus is higher than that of the 100%VA. The Resilient modulus of the RAP blended mixtures increases with the increase in the content of RAP percentage and for the RCA it was not consistent. The CBR values for the blended mixtures decreases with the increase in the percentage of the recycled aggregates. The micro-deval degradation test result for RCA was more than of VA due to presence adhere materials in RCA.
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Utilização de resíduos de concreto em concreto auto-adensávelBranco, Roberto Pagliosa [UNESP] 10 February 2012 (has links) (PDF)
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branco_rp_me_ilha.pdf: 820885 bytes, checksum: 92bc9984cf08068fd54072214c148bb4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O principal objetivo desse trabalho é buscar uma solução que viabilize melhorar as características do concreto auto-adensável (CAA) e que também possibilite o reaproveitamento dos resíduos gerados pela indústria da construção civil. O trabalho consiste em produzir CAA com adição de material fino constituído por resíduos de concreto em substituição ao agregado miúdo, objetivando obter uma mistura auto- adensável sem segregação, cujo resultado seja benéfico para as propriedades físicas e mecânicas do concreto. Para tanto, foram realizados ensaios visando a avaliar as propriedades do concreto no estado fresco, segundo o método proposto por Tutikian (2004), a fim de otimizar a sua resistência no estado endurecido com o menor custo possível. E ainda, examinar diferentes faixas granulométricas procurando uma correlação que propicie condições adequadas de trabalhabilidade e de resistência mecânica. Os ensaios ocorreram no Laboratório de Engenharia Civil da UNESP e no Laboratório CESP de Engenharia Civil em Ilha Solteira-SP. Os concretos confeccionados com resíduo mostraram-se viáveis por apresentarem resultados próximos ao do concreto usado como referência, fazendo com que os resíduos sejam uma ótima opção como material reciclável / The main objective of this paper is to search for a solution that makes possible to improve the characteristics of the self-compacting concrete(SCC) and also allows the reuse of the waste generated by the construction industry civil. The work is to produce SCC with the addition of fine material consisting of concrete waste to replace the fine aggregate in order to obtain a compacting mixture without self- segregation; the result is beneficial for physical and mechanical properties of concrete. To this end, tests were carried out in order to evaluate the properties of fresh concrete, according to the method proposed by Tutikian (2004), in order to optimize its resistance in the hardened condition with the lowest possible cost. And also examining different granulometric compositions in order to look for a correlation that provides appropriated working conditions and mechanical strength. The trials took place at the Laboratory of Civil Engineering of UNESP and at CESP Laboratory of Civil Engineering of Ilha Solteira-SP. The concrete made from waste appear to be viable because presents results close to the concrete used as a reference, so that residues shall be a great choice as recyclable material
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Influência das características morfológicas de britas graníticas e gnaíssicas na resistência à compressão do concretoSILVA, Mickey Anderson Paixão da 09 August 2016 (has links)
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Previous issue date: 2016-08-09 / Em virtude dos agregados constituírem os recursos minerais mais acessíveis e também serem responsáveis por uma enorme parcela do material consumido na construção civil, faz-se necessário um estudo mais aprofundado a respeito da utilização e aplicação dessa matéria prima. O objetivo principal é qualificar a relação entre os resultados de resistências à compressão do concreto, obtidos por meio de testes feitos em corpos-de-prova moldados com diferentes tipos de brita, de modo a identificar aquela que proporciona uma maior resistência no mesmo, quando submetido aos esforços uniaxiais de compressão. Para isso foram escolhidas amostras de rochas, sendo três granitos e três gnaisses para análise da qualidade do concreto produzido a partir das respectivas britas. As britas foram analisadas macroscopicamente e todas as amostras foram submetidas às mesmas etapas de britagem, e posteriormente o material resultante dessa etapa passou pelo peneirador mecânico. Através desse processo, avaliou-se individualmente o índice de forma, o módulo de finura e o percentual dos minerais com clivagem dos devidos tipos de rochas afim de entender melhor o motivo dos posteriores resultados do comportamento do concreto com relação à trabalhabilidade e resistência a compressão uniaxial para cada um dos tipos de brita. A escolha do tipo de cimento torna-se muito relevante para esta análise. Faz-se necessário a escolha de um cimento que dê margem para que o tipo de brita seja a variável mais importante e decisiva no processo de resistência. Observa-se também que o índice de forma está relacionado ao percentual de minerais presentes na rocha que apresentam planos de clivagem. O valor do índice de forma está diretamente relacionado aos teores de minerais com um ou mais planos de clivagem contidos em cada amostra. Por fim, ficou constatado que o concreto que apresentou a maior resistência à compressão foi confeccionado por agregados com os menores módulos de finura; já os agregados com o maior módulo de finura resultaram num dos concretos menos resistentes. / Because the aggregate constitute the most accessible mineral resources and also account for a huge portion of the consumed in construction material, it is necessary to further study regarding the use and application of this raw material. The main goal is to qualify the relationship between the results of resistance to the concrete compressive obtained by means of tests made on specimens test pieces molded with different types of gravel, in order to identify one that provides greater strength in that when subjected to uniaxial compression efforts. For this rock samples were selected: three and three granite gneiss for analysis of the quality of concrete produced from the respective gravel. The gravel was analyzed macroscopically and all samples were subjected to the same steps of crushing, and then the resulting material has passed this stage by mechanical sieving. Through this process, we assessed individually the form of an index, the fineness modulus and percentage of minerals with cleavage of proper rock types in order to better understand the reason for the subsequent behavior of concrete results regarding the workability and compressive strength uniaxial for each type of grit. The choice of the type of cement becomes very relevant to this analysis. It is necessary to choose a cement margin so that the type of grit is most important and crucial variable in resistance process. It is also observed that the form of an index is related to the percentage of minerals present in the rock show cleavage planes. The value of the medium index is directly related to mineral contents in one or more cleavage planes contained in each sample. Finally, it was found that the concrete with the highest compressive strength was made by households with the lowest fineness modules; since aggregates with higher fineness modulus resulted in the least resistant concrete.
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Exciton polariton modes in nanostructuresGentile, Martin James January 2016 (has links)
In this thesis, original theoretical and numerical investigations into the interaction of light with excitonic nanostructures are presented, in a bid to demonstrate that excitonic nanostructures are viable alternatives to the use of plasmonic nanostructures where electric field enhancement and confinement are sought. In particular, the field enhancement and confinement around excitonic nanostructures on resonance is shown to be comparable if not in excess of that around noble metal nanoparticles such as gold and silver. These excitonic modes, when set in the context of a core-shell geometry, are shown to offer tunability through nanoparticle design and through the index of the environment. In addition, hybrid `hyperbolic' and `plexcitonic' modes are shown to offer similar properties in metallic-excitonic nanostructures. Altogether, these excitonic and hybrid excitonic modes are shown to have potential in nanophotonic applications.
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ESTIMATION OF AGGREGATE RESERVES IN OHIOMahmoud, Khaled 07 May 2022 (has links)
No description available.
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Establishment of 3D culture protocols for the maintenance and expansion of human pluripotent stem cell aggregates in a low scale platform and in the DASbox® Mini-Bioreactor SystemHernandez-Bautista, Carlos Alberto 27 July 2022 (has links)
The human Embryonic Stem Cells (hESCs) and human induced Pluripotent Stem Cells (hiPSCs) have offered numerous advantages including but not limited to model diseases, high-throughput drug screening, and regenerative purposes. However, the employment of monolayer cultures has not been sufficient to mimic the in vivo stem cells niche. Thus, three-dimensional suspension cultures have helped us to advance our knowledge and ease the development of the human organs’ counterparts, commonly referred as organoids. Currently, the challenge is the generation of homogenous and reproducible human Pluripotent Stem Cell (hPSC) aggregates, the basic cellular unit to derive organoids. To date, the Ultra-Low Attachment (ULA) 6-well plates have been routinary used for the hPSC aggregates formation, which mainly relies on the inhibition of the Rho-associated kinase (ROCK) pathway resulting in the enhancement of cell survival coming from cryopreserved stocks or when passaging. However, little is known in this regard when analyzing the aggregate formation of hPSCs with two widely used compounds: RevitaCellTM Supplement and Y27632. Importantly, due to the high demand required from the regenerative medicine, I aimed to upscale the hPSC aggregates production in the DASbox® Mini-Bioreactor System. In this thesis, I established protocols for the hPSC aggregates formation by using two different types of media in two platforms being the ULA 6-well plates and the DASbox® Mini-Bioreactor System. In addition, I demonstrated that monolayer confluence cultures before single cell inoculations are paramount for the formation of bona fide hPSC aggregates in healthy and X aneuploid hiPSCs, precisely two hESCs and five hiPSCs.
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