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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Internal mixing in a mine lake /

Huber, Anita. January 2006 (has links)
Thesis (M.Eng.Sc.)--University of Western Australia, 2007.
2

Diseño y evaluación de concreto estructural de f’c 280 kg/cm2 elaborado con aguas residuales domésticas tratadas mediante procesos biológicos como alternativa al uso de agua potable en Lima Metropolitana

Catanzaro Mesía, Gianfranco, Zapana Gago, Oscar Anthony 01 August 2019 (has links)
El tema de esta investigación se centra en el diseño y la evaluación de concreto elaborado a partir de aguas residuales domesticas tratadas mediante dos tipos diferentes de procesos biológicos (lodos activados y humedales artificiales) como alternativa al uso de agua potable en Lima Metropolitana. Actualmente, se conoce que la disponibilidad de agua potable en la ciudad de Lima no es abundante y las proyecciones a futuro indican que la demanda por el incremento poblacional generará problemas de escasez de este recurso. Debido a ello, es importante tomar medidas al respecto que permitan ahorrar este valioso recurso en industrias que consumen más agua como la de producción de concreto. Ante esta problemática, el uso de aguas residuales tratadas se muestra como una posible opción para reemplazar al agua potable en la elaboración de concreto. La presente tesis se desarrolla en 7 capítulos detallados a continuación: En Capítulo 1, se presenta el marco teórico, el cual incluye las principales bases teóricas utilizadas. En el Capítulo 2 se definen las características de los materiales empleados y la metodología de la investigación. En el Capítulo 3 se muestran los resultados de los ensayos y evaluaciones realizadas. En el Capítulo 4 se realiza la verificación de los resultados y luego la discusión de los mismos. En el Capítulo 5 se presentan las conclusiones y en el Capítulo 6 se detallan las recomendaciones. Finalmente, en el Capítulo 7 se muestran las referencias de otras investigaciones citadas en la presente Tesis y, adicionalmente, se muestran los anexos de la investigación. Al final de la investigación, se determinó que el concreto elaborado con aguas residuales domesticas tratadas mediante el proceso biológico de lodos activados si es una alternativa factible al uso de agua potable al presentar resultados similares a los del grupo de control. / The subject of this research focuses on the design and evaluation of concrete made from domestic wastewater treated by two different types of biological processes (activated sludge and artificial wetlands) as an alternative to the use of drinking water in the city of Lima. Currently, it is known that the availability of drinking water in the city of Lima is not abundant and future projections indicate that the demand due to population increase will generate water shortage problems. Because of this, it is important to take measures to save this valuable resource in industries that consume more water, such as concrete production. Given this problem, the use of treated wastewater is shown as a possible option to replace drinking water in concrete production. This thesis is developed in 7 chapters detailed below: In Chapter 1, the theoretical framework is presented, which includes the main theoretical bases used. Chapter 2 defines the characteristics of the materials used and the methodology of this investigation. Chapter 3 shows the results of the tests and evaluations carried out. In Chapter 4, the results are verified and then discussed. In Chapter 5 the conclusions are presented and in Chapter 6 the recommendations are detailed. Chapter 7 shows the references of other research cited in this Thesis and, finally the annexes of the thesis are shown. At the end of the investigation, it was determined that concrete made with domestic wastewater treated by the biological process of activated sludge is a feasible alternative to the use of potable water when presenting results similar to those of the control group. / Tesis
3

Vliv pH záměsové vody na hydrataci a mechanické vlastnosti cementových kompozitů. / Effect of pH of mixing water on hydration and mechanical properties of cement composites.

Bezděk, Ondřej January 2015 (has links)
This master’s thesis is focused on the effect of mixing water pH value on hydration and mechanical properties of cement composites based on portland cement. Source material was CEM I 42,5 R. Hydration process was analyzed by isoperibolic calorimetry, X-ray diffraction analysis and differential thermal analysis. Compressive and flexural strength was examined as mechanical properties. The samples microstructure was observed by scanning electron microscopy. Influence of mixing water pH value on flexural and compressive strength, retardation of hydration and ratio of individual phases was shown.
4

Avaliação da qualidade de mistura de águas de salinidades diferentes com e sem dessalinização solar para a Região do Semi-Árido da Paraíba. / Quality evaluation of water mixtures of different salinities with and without solar desalination for the Paraíba Semi-Arid Region.

COSTA, Silvana Nunes da. 08 November 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-11-08T23:51:54Z No. of bitstreams: 1 SILVANA NUNES DA COSTA - DISSERTAÇÃO PPGECA 1992..pdf: 17415948 bytes, checksum: cbc9fe9ab0e76268ae3458f2074e4013 (MD5) / Made available in DSpace on 2018-11-08T23:51:54Z (GMT). No. of bitstreams: 1 SILVANA NUNES DA COSTA - DISSERTAÇÃO PPGECA 1992..pdf: 17415948 bytes, checksum: cbc9fe9ab0e76268ae3458f2074e4013 (MD5) Previous issue date: 1992-08-27 / Na região do Semi-Arido do Estado da Paraíba, a maioria dos mananciais superficiais e subterrâneos não somente tem pequena caudabilidade como também apresentam elevado teor de salinidade (cloreto - C1 - > 800 mg/1). Tais águas de alta salinidade e alta força iônica são impróprias para o consumo humano e/ou para outras finalidades. como tentativa para contornar esta situação, este trabalho mostra um estudo aprofundado de qualidade de águas de mistura em termos de grau de salinidade e de grau de saturação. A partir da utilização de águas sintéticas de alta e de baixa salinidade e de um desalinizador solar, em escala reduzida, tipo convencional, foram analisados os seguintes tipos de misturas: (I) tipo MD ou de água de alta salinidade com água dessalinizada e (II) tipo MB ou de água de alta salinidade com água de baixa salinidade. As águas sintéticas de alta salinidade foram preparadas com composição química similar àquelas da região do Semi-Árido Paraibano, e foi inserida uma espécie carbônica para simular águas naturais. Dois sistemas foram utilizados: a saber: (I) MaHCO3 + MaC1 + CaSO42H20 + H0O e (II) MaHCO3 + MaC1 + MgC12 + H0O. A variação do grau de salinidade foi feita a partir do teor de cloreto, ou seja: de 1.500 mg/1 a 3000 mg/1 para as águas de alta salinidade do sistema I, de 1000 mg/1 a 3500 mg/1 para as do sistema II e, finalmente, de 100 mg/1 a 200 mg/1 para as de baixa salinidade dos dois sistemas. Todas as simulações das águas e as determinações experimentais foram feitas no Laboratório de qualidade de Água da Companhia de Água e Esgotos da Paraíba - CAGEPA no alto Branco, Campina Grande, PB. Os resultados experimentais mostraram que ambos os processos de mistura são eficientes para a redução da salinidade das águas naturais e produzem um maior volume de água. A teoria do sistema carbonatado de Loewnthal & Marais (1976 e 1986) foi aplicada para verificação do grau de saturação das águas (potencial de precipitação/dissolução de carbonato de cálcio - CaCO3). Os resultados mostraram que as águas finais de ambas os tipos de misturas, apesar de leve tendência a subsaturação são praticamente estáveis. / In the Semi-Arid region of Paraiba State the majority of the superficial waters and groundwaters not only has a small yield hut also shows a high salinity concentration (chloride - CI- > 800 mg/1). Such waters of high salinity and high ionic strength are inadequate for human use and/or for other uses. In order to help to minimize this problem, this work shows a deep study on the quality of blended waters concerning its salinity and saturation degree. From the preparation of synthetic high salinity waters and low salinity waters and with the aid of a solar distiller, built in reduced scale and of the conventional type, it were analized the following types of blend, (i) blend MB or high salinity water with dessalinized water and (ii) blend MB or high salinity water with Lou salinity water. The synthetic high salinity waters were prepared with chemical composition similar to those of the Semi-Arid region of Paraiba and it was included a carbonic species in order to simulate a natural water. Two types of waters were used, i.e.: (I> MaHC03 + MaCl + CaSGU2HK0 and (II) MaHC03 i MaCl f MgC'ls: + CaCla + H3O. The degree of salinity was prepared from the chloride - Cl~ concentration; i.e.; from C1 - (mg/1) 1500 to 3000 for high 'salinity waters of the system I, from C1 - (mg/1) 1000 to 3500 for those of the system II and finally, from Cl~ (mg/1) 100 to 200 for low salinity waters. All simulations of the waters - and experimental determinations were made at the Laboratório of Water Quality of the Water and Wastewater Agency of Paraiba CAGEPA, in Alto Branco township, Campina Grande, PB. The experimental results indicate that both blending processes are efficient for minimizing the salinity of natural waters and produce a greater water volume. The theory of the carbonated system of Loewenthal & Marais (1976 and 1986) was applied to evaluate the saturation degree of the waters (potencial of precipitation/dissolution of calcium carbonate - CaCDs). The results showed that the final waters of both blending types although showing a slight subsaturation tendence, are practically stable.

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