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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

Physiological studies of different sorghums and barleys during malting

Agu, Reginald C. January 1997 (has links)
No description available.
2

The Effect of Various Design Variables on the Separation of Two Immiscible Liquids by Continuous Gravity Decantation

Manchanda, Krishan 10 1900 (has links)
<p> The separation of distilled water and coconut fatty acid (CNFA) was investigated in a 4 in. x 16 in. vertical gravity decanter to determine the most significant design variables. The design variables studied were tangential versus perpendicular feed flow, height/diameter ratio, the total feed flow rate, the temperature and the intertace position with respect to feed inlet. The criteria used were the calculated immiscible concentration of water in CNFA overflow (Cw) and that of CNFA in water underflow (Co), The test conditions were arranged according to a Central Composite Design based on Box Method of Experimentation. Two levels of inlet geometry and five levels of each of the other four variables were studied. The range of variables were 1. Inlet geometry Tangential and Perpendicular Feed Flow 2. Height/Diameter Ratio 3/1 to 4/1 3· Total Feed Flow rate 160 cc/min. to 320 cc/min. 4. Temperature 40° to 80°c. 5· Interrace Position 2" below feed inlet to 2" above feed inlet The Overall residence time in the decanter ranged from 7.5 to 12.5 minutes. The drop size distribution of the incoming dispersion was measured by taking photomicrographs for all the runs. </p> <p> It was found that the tangential feed flow was slightly better but not significantly better for the separation of two immiscible liquids. Statistical analysis revealed that 95% confidence level height/diameter ratio, flow rate and temperature, respectively, are the most important design variables for the separation of CNFA from water underflow. The dependence of Cw on height/diameter ratio of Co on the interface position was interpreted to mean that the theoretical, plug flow residence time within each phase is the most important design variable. Interaction between variables and second order constants were not found significant at 95% confidence level. Sedimentation rather than coalescence appeared to be the controlling factor in the present study. </p> / Thesis / Master of Engineering (MEngr)
3

Lagunage anaerobie : modélisation combinant la décantation primaire et la dégradation anaerobie

Effebi, Kôkôh Rose 10 March 2009 (has links)
Cette étude a porté sur le lagunage anaérobie, de manière générale, une synthèse bibliographique a permis de montrer son fonctionnement, son dimensionnement et ses performances. Un cas détude des performances de la station de Sidi Bou Ali localisé en Tunisie a permis de mettre en exergue de bons rendements épuratoires avec 72,21% MES, 70,86% DCO et 87,43% DBO5. Elle a permis entre autre de développer un modèle de décantation qui a été appliqué avec succès aussi bien aux données des matières en suspension de la station pilote de traitement des eaux usées du CERTE de Tunis quaux données sur les oeufs dhelminthes de la station dOujda au Maroc. Nous obtenons en moyenne des temps de décantation correspondant à 50% délimination compris entre 60 à 120 minutes pour les MES des différents bassins et de 1,97 heures pour les oeufs dhelminthes. Au cours des travaux, il a été également proposé une méthodologie qui a permis de mesurer les cinétiques des activités dacidogenèse et de méthanogenèse sur une installation de type lagunage anaérobie en vraie grandeur localisée en Tunisie. Par ailleurs, une stoechiométrie des processus dhydrolyse et dacidogenèse sur les composés retenus à savoir le glucose, les protéines et les lipides (tous les trois regroupés sous forme dun substrat combiné), concernant les eaux usées domestiques a été mis en place. Cette démarche intègre la production de biomasse, de manière à pouvoir coupler la cinétique des mesures avec la stoechiométrie. En effet lensemble de cette approche a été rassemblé et a permis via le logiciel WEST davoir des résultats satisfaisants des rendements mesurés sur station et calculés par le logiciel sur le modèle du lagunage anaérobie portant sur la combinaison de la décantation primaire et la dégradation anaérobie. Cette modélisation conduit à la réduction de la complexité du modèle ADM1 et à une simulation pratique des activités dacidogenèse et de méthanogenèse. Enfin, la réalisation de ce travail a engendré le développement de la mise en place de deux bases de données : lune bibliographique et lautre sur le lagunage en générale appelée Waste Stabilisation Pond (WSP) data base. Les données de cette dernière ont été analysées statistiquement pour illustrer les performances épuratoires de cinq stations de type lagunage, localisées en Tunisie.
4

Studies on the ecology and taxonomy of nematodes of Saldanha Bay, South Africa

Hendricks, Martin Gustav John January 2013 (has links)
Philosophiae Doctor - PhD / Few studies of shallow water marine nematodes have been conducted around South Africa, and none from the west coast. Here, I analyse the composition of nematode communities from six stations along a 3 km transect in Saldanha Bay during both summer and winter, in order to describe the communities present and to explore the effects of sediment composition and heavy and trace metal concentrations on community structure. In order to put the local data into a global context, these data are analysed together with some consolidated data from elsewhere and patterns of richness and composition (at the level of genus and species) examined The transect in Saldanha Bay extended from below a mussel raft at one end into the bay, and six cores (35.7mm diameter) were collected at each station. All nematodes were counted and 100 randomly identified from each core. A total of 136 nominal species, 117 genera and 36 families were identified from both summer and winter stations. Nematode abundance was highest at stations under the mussel raft, which were characterized by high mud content and high concentrations of trace and heavy metals: diversity was comparatively low and the assemblage was dominated by a few, non-selective deposit feeders (especially Sabatieria). Abundance decreased, but diversity increased, with an increase in distance from the mussel raft, which was coupled with an increase in the particle size of sediments and a significant reduction in metal concentrations. There were three dominant (Comesomatidae, Desmodoridae and Linhomoeidae, present in 96%, 85% and 83% of samples, respectively) and four subdominant families (Chromadoridae, Microlaimidae and Xyalidae, all in 79% of samples) that were largely responsible for determining the community structure across the bay. Multivariate analysis of the data using PRIMER indicated that copper was the single variable that best accounted for the structure of the communities (70.1%), and the best 2-variable combinations were copper and organic nitrogen (70.3%), followed by copper, organic nitrogen and mean grain size (69.7%). Abundance was higher at all stations in winter than summer, and the results of the PERMANOVA test on station and season indicated that the variation in between Station- Season accounted for 27% of the differences in community structure. Although these results should be treated with caution owing to limited temporal sampling, they are similar to those obtained elsewhere in the world and indicate that nematodes can be used to study anthropogenic impacts in a local context. Despite the fact that Saldanha Bay has been subjected to industrial activities for more than thirty years, estimates of species richness for Saldanha Bay were surprisingly high: S= 136; ICE = 150; CFE= 173. As too were estimates of generic richness (S= 117; ICE = 131; CFE= 149), which were the fourth most rich of those global sites compared from similar depths. Incorporation of these data into a global dataset revealed an absence of any clear latitudinal pattern in the distribution of richness (genera or families), and there was no obvious geographic structure to global communities, based on the available data. These results suggest that genera and families are poor proxies for species (at the evolutionary level, but not at the ecological level) and they support the idea that everything is everywhere. Comments on ways that nematode research can be advanced in South Africa are made.
5

Karren On Quatsino Fm. Dip Slopes Recently Exposed By Deforestation Northern Vancouver Island

Gladysz, Kathleen Joan 10 August 1987 (has links)
<p> This study reports on karren forms on limestone dip slopes, which were recently exposed by deforestation on the Quatsino Formation and observable relationships of the karren features of a specific sl~pe are represented as a detailed map. Also, many relationships of gravitomorphic runnel characteristics are analyzed for significance. Runnel types being considered are Hortonian, decantation and composite forms. Solution runnel width, depth and width/depth ratio are studied in association with length. These relationships determine whether the runnel types conform to a theoretical model. Typical aeas·ares of the karren in this area were also recorded. Composite forms are the most abundant because Hortonian and decantation runnels amalgamate beyond about 3m to form composites. All the runnel types, excluding the decanters, illustrate the perfect minimum friction open-channel cross-section. </p> / Thesis / Bachelor of Arts (BA)
6

ESTUDO DE MECANISMOS DE RETENÇÃO DE ESPÉCIES METÁLICAS NO SEDIMENTO DAS LAGOAS DE DECANTAÇÃO DO ATERRO CONTROLADO DO BOTUQUARA

Wiesinieski, Joelma Adriane 05 March 2009 (has links)
Made available in DSpace on 2017-07-24T19:37:59Z (GMT). No. of bitstreams: 1 Joelma Adriane Wiesinieski.pdf: 2892011 bytes, checksum: cda8a9b8b1f38d58c117f0c13269172b (MD5) Previous issue date: 2009-03-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The final disposition place of trash at Ponta Grossa city started out in 1969, in an appearance of garbage in the Botuquara’s region, and became the controlled garbage earthwork in 2001. The leach forming in this kind of landfill is, currently, the purpose of many studies principally in the vehicular of diseases and damages to the environment. The aim in this paper is to evaluate the characteristics of the sediments of the decantation lagoons that receive the percolado from the “Aterro Controlado do Botuquara” and of the soil next to the place where the last lagoon liberates to the environment this percolado, in order to evaluate if it is occurring retention of weighty metals, how is this retention, and also if the near area is receiving these metallic species. It were done accomplishing analyses of pH, OM, organic carbon, total nitrogen, C:N relation, CEC, K+, phosphates and sand contents, clay and silt to the sediments, as well as determined the concentrations of Cu, Cr, Fe, Mn, Ni, Ag, Pb and Zn the carbonates, organic substance, oxides of iron and manganese and the easily exchangeable ones in the samples of the sediments.The results show that the sediment possesss high texts of Mn, Fe, Cr, Ag, Ni, Cu, in some fractions of the collection points, mainly in the total fraction. The treatment lagoons are not being efficient, because of the total metal found in the landfill´s leach, when it is launched in the water will be able to modify its properties and to compromise its quality. / A disposição final do lixo da cidade de Ponta Grossa-Pr teve início em 1969, com a criação de um lixão na região do Botuquara, que em 2001 passa a aterro controlado. A formação de lixiviado neste tipo de aterro é atualmente, objetivo de vários estudos, principalmente no que se refere à veiculação de doenças e aos danos ambientais. Este estudo tem por objetivo avaliar as características dos sedimentos das lagoas de decantação que recebem o percolado do Aterro Controlado do Botuquara, e do solo próximo ao local onde a ultima lagoa libera para o meio ambiente o percolado, a fim de avaliar se está ocorrendo à retenção dos metais pesados, como é esta retenção, e também, se área próxima está recebendo estas espécies metálicas. Foram realizadas análises de pH, carbono orgânico, matéria orgânica, capacidade de troca catiônica, nitrogênio total, relação carbono: nitrogênio, potássio, fosfato, teor de argila, areia e silte , assim como determinadas as concentrações de Cu, Cr, Fe, Mn, Ni, Ag, Pb e Zn ligados a carbonatos, matéria orgânica, óxidos de ferro e manganês e os facilmente trocáveis nas amostras dos sedimentos.Os resultados mostram que o sedimento possui teores elevados de Mn, Fe, Cr, Ag, Ni, Cu, , em algumas frações dos pontos de coleta, principalmente na fração total. As lagoas de tratamento não estão sendo eficientes, para retenção total de metais presentes no lixiviado do aterro, se este for lançado em corpos de águas, poderá alterar suas propriedades e comprometer sua qualidade.
7

An Automatic Biodiesel Decanting System for the Optimization of Glycerin Separation Time by Applying Electric Field and Temperature

Bulnes, Kevin, Paredes, Diego, Vinces, Leonardo 01 January 2021 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / During biodiesel production, crude biodiesel and glycerin are separated in resting tanks due to gravity and differences in density, glycerin accumulates at the base of the contender; such operation is called decantation. The decantation stage, within the production of biodiesel based on recycled oil, takes from 8 to 24 h to complete. Therefore, the development of an automatic biodiesel decanting system is presented in order to optimize the production time in the line of this bio-fuel. The process consists of applying an electric field through two electrodes at 9 kV and simultaneously applying temperature. The results of the implementation showed that the production time was reduced by up to 99% without affecting the quality of biodiesel, according to the parameters of the American Society for Testing and Materials (ASTM). / Revisión por pares
8

Využitelnost výpalků z výroby ethanolu / Usability of stillage from ethanol production

Audy, Dan January 2015 (has links)
This work solves the use of stillage from ethanol production. Also solves processing into material DDGS and then solves the material and energy balance. This material and energy balance was calculated for 7070 kg of stillage per hour. The final energy requirements of the process were based on the amount of stillage produced to obtain 1 m3 of ethanol. The results of this work offer an insight to the problems of processing stillage. Thanks to conversion for 1 m3 of produced ethanol, results is also offerring the possibility of fast conversion of an approximate energy needed for devices of other capacities.
9

Desenvolvimento de tecnologia alternativa para tratamento de efluentes visando a reutilização da água de postos de lavagem de veículos / Development of alternative technology for wastewater treatment aiming the recovery of the water from car wash station

Zimmermann, Valmir Elemar 15 February 2008 (has links)
Made available in DSpace on 2017-07-10T18:08:09Z (GMT). No. of bitstreams: 1 Arquivo de texto 1.pdf: 2186590 bytes, checksum: 8cfe993c740c2908a563e68a70f3ec3d (MD5) Previous issue date: 2008-02-15 / The increasing concern with the environment and specially with the use of the water resources resulted in the increasing valorization of the drinking water as well of consumption. Innumerable are the activities that use this resource, one of them, the Car Wash Station (CWS), object of this research. In Brazil, about 32,700 CWS approximately consume 3.7 millions of cubical meters of water per month that transform it in wastewater. In this context, this work had, as general objective, the development of alternative technology for wastewater treatment aiming the recovery of the water from car wash station. For so much, the methodology had as base seven main aspects: 1) diagnosis of the current situation around the activity of CWS; 2) characterization of the crude wastewater generated by CWS; 3) mathematical modeling to identify the critical factors of project; 4) development of the prototype; 5) researches of patents to verify the innovation; 6) elaboration of the process for patent request and 7) specifications of the criteria for development of installation and operation manuals of the wastewater treatment system. In the case of Toledo/PR city, from the 47,155 registered self-driven vehicles (of the whichonly 27% pass for CWS), with a medium consumption of 2682,5 m3 water per month, it was verified a generation of 2.921,14 m3 wastewater per month with highly variable characteristic, having only 97% of the CWS some treatment system. The inefficiency of the conventional systems was verified and the analysis resulted in the proposition/development of two technologies (patent request number MU8701195-6 23/07/2007 and number MU8701196-4 23/07/2007) having, among their characteristics, the low cost,installation/operation/maintenance easiness, need of little space, efficiency and versatile in application form. In this way, this work should intended to contribute with the minimization of the environmental problem around the activity of CWS / A crescente preocupação com o meio ambiente e, em especial com o uso dos recursos hídricos resultou na valorização crescente da água potável como bem de consumo. Inúmeras são as atividades que utilizam este recurso, uma delas, os Postos de Lavagem de Veículos (PLV s), objeto da pesquisa. No Brasil, cerca de 32.700 postos de lavagem transformam aproximadamente 3,7 milhões de metros cúbicos de água/mês em efluente. Neste contexto, este trabalho teve como objetivo geral o desenvolvimento de tecnologia alternativa para tratamento de efluentes visando a reutilização da água de postos de lavagem de veículos. Para tanto, a metodologia teve como base sete aspectos principais: 1) Diagnóstico da situação atual em torno da atividade dos PLV s; 2) Caracterização do efluente bruto gerado pelos PLV s; 3) Modelagem matemática para identificar os fatores críticos de projeto; 4) Desenvolvimento do protótipo; 5) Pesquisa em banco de patentes para verificar a inovação; 6) Elaboração do processo para pedido de patente e 7) Especificações dos critérios para desenvolvimento de manuais de instalação e operação do sistema de tratamento de efluentes de PLV s. Para o caso da cidade de Toledo-PR constatou-se a existência de 47.155 veículos automotores cadastrados (dos quais apenas 27% passam pelos PLVs), com um consumo médio de 2682,5 m3 de água/mês, geração de 2.921,14 m3 de efluente/mês com característica altamente variável, tendo apenas 97% dos postos algum sistema de tratamento. Constatou-se a ineficiência dos sistemas convencionais cuja análise resultou na proposição/desenvolvimento de duas tecnologias (pedido de patente N° MU8701195-6 de 23.07.2007 e Nº MU8701196-4 de 23.07.2007) tendo entre suas características o baixo custo, facilidade de instalação/operação/manutenção, necessidade de pouco espaço físico, eficiente e versátil na sua forma de aplicação. Desta forma, este trabalho deve contribuir com a minimização da problemática ambiental em torno da atividade dos PLV s.

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