• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 69
  • 28
  • 14
  • 8
  • 6
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 210
  • 30
  • 25
  • 24
  • 19
  • 18
  • 16
  • 15
  • 14
  • 13
  • 12
  • 12
  • 11
  • 11
  • 11
  • 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.
101

Powered addition as modelling technique for flow processes

De Wet, Pierre 03 1900 (has links)
Thesis (MSc (Applied Mathematics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The interpretation – and compilation of predictive equations to represent the general trend – of collected data is aided immensely by its graphical representation. Whilst, by and large, predictive equations are more accurate and convenient for use in applications than graphs, the latter is often preferable since it visually illustrates deviations in the data, thereby giving an indication of reliability and the range of validity of the equation. Combination of these two tools – a graph for demonstration and an equation for use – is desirable to ensure optimal understanding. Often, however, the functional dependencies of the dependent variable are only known for large and small values of the independent variable; solutions for intermediate quantities being obscure for various reasons (e.g. narrow band within which the transition from one regime to the other occurs, inadequate knowledge of the physics in this area, etc.). The limiting solutions may be regarded as asymptotic and the powered addition to a power, s, of such asymptotes, f0 and f¥ , leads to a single correlating equation that is applicable over the entire domain of the dependent variable. This procedure circumvents the introduction of ad hoc curve fitting measures for the different regions and subsequent, unwanted jumps in piecewise fitted correlative equations for the dependent variable(s). Approaches to successfully implement the technique for different combinations of asymptotic conditions are discussed. The aforementioned method of powered addition is applied to experimental data and the semblances and discrepancies with literature and analytical models are discussed; the underlying motivation being the aspiration towards establishing a sound modelling framework for analytical and computational predictive measures. The purported procedure is revealed to be highly useful in the summarising and interpretation of experimental data in an elegant and simplistic manner. / AFRIKAANSE OPSOMMING: Die interpretasie – en samestelling van vergelykings om die algemene tendens voor te stel – van versamelde data word onoorsienbaar bygestaan deur die grafiese voorstelling daarvan. Ten spyte daarvan dat vergelykings meer akkuraat en geskik is vir die gebruik in toepassings as grafieke, is laasgenoemde dikwels verskieslik aangesien dit afwykings in die data visueel illustreer en sodoende ’n aanduiding van die betroubaarheid en omvang van geldigheid van die vergelyking bied. ’n Kombinasie van hierdie twee instrumente – ’n grafiek vir demonstrasie en ’n vergelyking vir aanwending – is wenslik om optimale begrip te verseker. Die funksionele afhanklikheid van die afhanklike veranderlike is egter dikwels slegs bekend vir groot en klein waardes van die onafhanklike veranderlike; die oplossings by intermediêre hoeveelhede onduidelik as gevolg van verskeie redes (waaronder, bv. ’n smal band van waardes waarbinne die oorgang tussen prosesse plaasvind, onvoldoende kennis van die fisika in hierdie area, ens.). Beperkende oplossings / vergelykings kan as asimptote beskou word en magsaddisie tot ’n mag, s, van sodanige asimptote, f0 en f¥, lei tot ’n enkel, saamgestelde oplossing wat toepaslik is oor die algehele domein van die onafhanklike veranderlike. Dié prosedure voorkom die instelling van ad hoc passingstegnieke vir die verskillende gebiede en die gevolglike ongewensde spronge in stuksgewyspassende vergelykings van die afhankilke veranderlike(s). Na aanleiding van die moontlike kombinasies van asimptotiese toestande word verskillende benaderings vir die suksesvolle toepassing van hierdie tegniek bespreek. Die bogemelde metode van magsaddisie word toegepas op eksperimentele data en die ooreenkomste en verskille met literatuur en analitiese modelle bespreek; die onderliggend motivering ’n strewe na die daarstelling van ’n modellerings-raamwerk vir analitiese- en rekenaarvoorspellingsmaatreëls. Die voorgestelde prosedure word aangetoon om, op ’n elegante en eenvoudige wyse, hoogs bruikbaar te wees vir die lesing en interpretasie van eksperimentele data.
102

A regulação no contexto hospitalar enquanto ferramenta gerencial: a compreensão dos profissionais envolvidos

Rodrigues, Luciane Cristine Ribeiro [UNESP] 16 August 2013 (has links) (PDF)
Made available in DSpace on 2014-08-13T14:50:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-08-16Bitstream added on 2014-08-13T18:01:08Z : No. of bitstreams: 1 000737966_20150816.pdf: 69570 bytes, checksum: d8588e472005d8bc4a141fa6ca63f527 (MD5) Bitstreams deleted on 2015-08-17T11:07:09Z: 000737966_20150816.pdf,. Added 1 bitstream(s) on 2015-08-17T11:07:54Z : No. of bitstreams: 1 000737966.pdf: 897380 bytes, checksum: 2e97c5b664b0f0a918162f8ea4cbabb2 (MD5) / A necessidade de garantir o acesso de forma condinzente com os princípios e diretrizes da Política Nacional de Saúde, e considerar o atual contexto da utilização de leitos hospitalares, envolto à oferta insuficiente em relação à demanda, surge a necessidade de se pensar em propostas inovadoras de gestão, que comtemplem tais expectativas propostas pelo Sistema Único de Saúde, e consequentemente atenda às reais necessidades de saúde da população, proporcionando um cuidado oportuno e integral. Diante deste contexto, o que se questiona é se com a instalação de um Núcleo Interno de Regulação, enquanto instrumento de gestão, ocorreu melhoria com o fluxo de leitos? Os objetivos foram: conhecer a percepção dos gestores em relação ao processo de elaboração, implantação e implementação do NIR; conhecer a percepção dos médicos e enfermeiros, que atuam no NIR sobre a implantação e o funcionamento do NIR; compreender as fragilidades e potencialidades das ações desenvolvidas pelo NIR, a partir da percepção de médicos e enfermeiros que vivenciam a regulação de leitos no complexo HC. Os resultados da pesquisa evidenciam que apesar das dificuldades, há um impacto considerável deste serviço na gestão de leitos e vagas, e consequentemente na gestão hospitalar, porém destaca-se a necessidade de integração na rede de saúde, com o compartilhamento de novas propostas inovadoras de gestão, com vistas à superação das fragilidades no sistema de saúde, visando disponibilizar um cuidado contínuo e integral / The need the access so according to the principles and guidelines of the Health Policy and considering the current context of using the hospital beds, related to insufficient offer related to demand, arises the need to think of innovative proposals that management contemplate such expectations proposed by the Unified Health System, and consequently attend the real needs of health of the population, providing a comprehensive and timely integral. In this context, what is questioned is whether the installation of the Health care coordination and monitoring as a tool for management, improvement occurred in equating the beds? The objectives were to understand the perception of managers on the process of elaboration, implementation and deployment of NIR; to know the perception of doctors and nurses working in the NIR on its deployment and operation; understand the weaknesses and potential of the NIR already deployed, from the perception of doctors and nurses, who experience the regulation of t beds in HC institute. The survey results show that despite the difficulties, there is a considerable impact of this service in the management of beds and room, and consequently in hospital management, however we call the attention to the need for integration in the health system, with the sharing of innovative proposals management, aiming at overcoming the weaknesses in the health system, in order to provide a continuous and integral care
103

Tafonomia de moluscos com ênfase em Sistemas Estuarino-Lagunares da Planície Costeira do Rio Grande do Sul, Brasil

Ritter, Matias do Nascimento January 2013 (has links)
Acumulações de restos de moluscos são muito comuns tanto em ambientes marinhos plataformais quanto em depósitos lagunares e estuarinos da América do Sul, principalmente entre o Brasil e a Argentina. A formação destas concentrações conchíferas pode prover grande oportunidade para estudos tafonômicos, os quais ainda são raros nesta região. Existem ainda questões a serem respondidas, por exemplo, quanta informação biológica está preservada nestas concentrações? Ou, qual é a probabilidade de uma associação viva deixar um registro fóssil análogo? Os principais objetivos deste estudo foram: (i) investigar a influência dos processos ambientais na destruição de remanescentes biológicos, através da descrição das assinaturas tafonômicas presentes em conchas de moluscos de dois afloramentos da Laguna Tramandaí, nordeste do Rio Grande do Sul; e (ii) testar o potencial de preservação de associações de moluscos vivos, mortos e fósseis de lagunas e estuários da Planície Costeira do Rio Grande do Sul, com o intuito de compreender a qualidade da informação biológica preservada nestas associações fósseis de fácies lagunares holocênicas. O principal processo tafonômico é a dissolução. As conchas estão inseridas na zona tafonomicamente ativa e experimentam intensa dissolução, o que reduz a probabilidade de deixarem um registro fóssil. Todavia, a preservação de espécies da associação viva nos depósitos fósseis foi de 100% em nível regional, e as espécies presentes na associação morta não apresentaram boa preservação no registro fóssil recente (Holoceno), ao contrário do que é usualmente predito na bibliografia. Isso indica que a associação morta é enriquecida por espécies não indígenas, e parte deste aumento relativo da riqueza é transferida para a associação fóssil. O padrão observado na fidelidade de moluscos estuarinos é ocasionado pela (i) alta variabilidade temporal e espacial nas associações vivas, (ii) mistura espacial nas associação mortas e (iii) preservação diferencial, devido à destruição durante uma longa permanência na zona tafonomicamente ativa. Portanto, a dissolução é o principal processo tafonômico que altera a informação biológica em ambientes transicionais, embora a preservação seletiva possa introduzir vieses das associações vivas às fósseis. / Molluscan shell accumulations (shell beds) are very common in shallow marine and estuarine environments in South America and also on the continental shelf from Southern Brazil through Argentina. The development of these shell beds can provide a great opportunity to taphonomic studies, which are uncommon in this geographic location. For example, how much biological information is preserved within these shell beds? Or, what is the actual probability a local living community has to leave a fossil record corresponding to these shell deposits? The aims of this study are (i) to investigate the influence of environmental processes on the destruction of biological remains in a subtropical lagoonal setting by describing the taphonomic signatures occurring in the mollusk shells from the Tramandaí Lagoon, northeastern Rio Grande do Sul State; and (ii) to compare living assemblages (LAs), death assemblages (DAs) and fossil assemblages (FAs) from estuaries and lagoons in the Rio Grande do Sul Coastal Plain to understand the nature and quality of biological information preserved in fossil associations in Holocene lagoon facies. Dissolution appears to be a leading taphonomic agent in lagoonal environments according to the study. The shells are within the taphonomically active zone and, due to intense dissolution, they will most likely leave no geological record. Nonetheless, the preservation of living species in FA was 100% and species present in DA are not as good preserved in recent (Holocene) fossil record as originally thought from the literature. The present results indicate that both DAs and FAs from estuarine-lagoons environments are composed basically by nonindigenous species, with live-dead mismatch than for continental shelves. The fidelity pattern here observed for estuarine mollusks have been driven by (i) high temporal and spatial variability in the LAs, (ii) spatial mixing in the DAs and (iii) differential preservation of shells, due to long residence times in the taphonomically active zone. Dissolution is the main taphonomic process altering biological information in those environments, but differential preservation may be, perhaps, the responsible for introducing bias from living to fossil assemblages.
104

A regulação no contexto hospitalar enquanto ferramenta gerencial : a compreensão dos profissionais envolvidos /

Rodrigues, Luciane Cristine Ribeiro. January 2013 (has links)
Orientador: Carmen Maria Casquel Monti Juliani / Banca: Wilza Carla Spiri / Banca: Maria José Sanches Marin / Banca: Shirlene Pavelqueires / Banca: Marta Maria Melleiro / Resumo: A necessidade de garantir o acesso de forma codinzente com os princípios e diretrizes da Política Nacional de Saúde, e considerar o atual contexto da utilização de leitos hospitalares, envolto à oferta insuficiente em relação à demanda, surge a necessidade de se pensar em propostas inovadoras de gestão, que contemplem tais expectativas propostas pelo Sistema Único de Saúde, e consequentemente atenda às reais necessidades de saúde da população, proporcionando um cuidado oportuno e integral. Diante deste contexto, o que se questiona é se com a instalação de um Núcleo Interno de Regulação, enquanto instrumento de gestão, ocorreu melhoria com o fluxo de leitos? Os objetivos foram: conhecer a percepção dos gestores em relação ao processo de elaboração, implantação e implementação do NIR; conhecer a percepção dos médicos e enfermeiros, que atuam no NIR sobre a implantação e o funcionamento do NIR; compreender as fragilidades e potencialidades das ações desenvolvidas pelo NIR, a partir da percepção de médicos e enfermeiros que vivenciam a regulação de leitos no complexo HC. Os resultados da pesquisa evidenciam que apesar das dificuldades, há um impacto considerável deste serviço na gestão de leitos e vagas, e consequentemente na gestão hospitalar, porém destaca-se a necessidade de integração na rede de saúde, com o compartilhamento de novas propostas inovadoras de gestão, com vistas à superação das fragilidades no sistema de saúde, visando disponibilizar um cuidado contínuo e integral / Abstract: The need the access so according to the principles and guidelines of the Health Policy and considering the current context of using the hospital beds, related to insufficient offer related to demand, arises the need to think of innovative proposals that management contemplate such expectations proposed by the Unified Health System, and consequently attend the real needs of health of the population, providing a comprehensive and timely integral. In this context, what is questioned is whether the installation of the Health care coordination and monitoring as a tool for management, improvement occurred in equating the beds? The objectives were to understand the perception of managers on the process of elaboration, implementation and deployment of NIR; to know the perception of doctors and nurses working in the NIR on its deployment and operation; understand the weaknesses and potential of the NIR already deployed, from the perception of doctors and nurses, who experience the regulation of t beds in HC institute. The survey results show that despite the difficulties, there is a considerable impact of this service in the management of beds and room, and consequently in hospital management, however we call the attention to the need for integration in the health system, with the sharing of innovative proposals management, aiming at overcoming the weaknesses in the health system, in order to provide a continuous and integral care / Doutor
105

Tafonomia de moluscos com ênfase em Sistemas Estuarino-Lagunares da Planície Costeira do Rio Grande do Sul, Brasil

Ritter, Matias do Nascimento January 2013 (has links)
Acumulações de restos de moluscos são muito comuns tanto em ambientes marinhos plataformais quanto em depósitos lagunares e estuarinos da América do Sul, principalmente entre o Brasil e a Argentina. A formação destas concentrações conchíferas pode prover grande oportunidade para estudos tafonômicos, os quais ainda são raros nesta região. Existem ainda questões a serem respondidas, por exemplo, quanta informação biológica está preservada nestas concentrações? Ou, qual é a probabilidade de uma associação viva deixar um registro fóssil análogo? Os principais objetivos deste estudo foram: (i) investigar a influência dos processos ambientais na destruição de remanescentes biológicos, através da descrição das assinaturas tafonômicas presentes em conchas de moluscos de dois afloramentos da Laguna Tramandaí, nordeste do Rio Grande do Sul; e (ii) testar o potencial de preservação de associações de moluscos vivos, mortos e fósseis de lagunas e estuários da Planície Costeira do Rio Grande do Sul, com o intuito de compreender a qualidade da informação biológica preservada nestas associações fósseis de fácies lagunares holocênicas. O principal processo tafonômico é a dissolução. As conchas estão inseridas na zona tafonomicamente ativa e experimentam intensa dissolução, o que reduz a probabilidade de deixarem um registro fóssil. Todavia, a preservação de espécies da associação viva nos depósitos fósseis foi de 100% em nível regional, e as espécies presentes na associação morta não apresentaram boa preservação no registro fóssil recente (Holoceno), ao contrário do que é usualmente predito na bibliografia. Isso indica que a associação morta é enriquecida por espécies não indígenas, e parte deste aumento relativo da riqueza é transferida para a associação fóssil. O padrão observado na fidelidade de moluscos estuarinos é ocasionado pela (i) alta variabilidade temporal e espacial nas associações vivas, (ii) mistura espacial nas associação mortas e (iii) preservação diferencial, devido à destruição durante uma longa permanência na zona tafonomicamente ativa. Portanto, a dissolução é o principal processo tafonômico que altera a informação biológica em ambientes transicionais, embora a preservação seletiva possa introduzir vieses das associações vivas às fósseis. / Molluscan shell accumulations (shell beds) are very common in shallow marine and estuarine environments in South America and also on the continental shelf from Southern Brazil through Argentina. The development of these shell beds can provide a great opportunity to taphonomic studies, which are uncommon in this geographic location. For example, how much biological information is preserved within these shell beds? Or, what is the actual probability a local living community has to leave a fossil record corresponding to these shell deposits? The aims of this study are (i) to investigate the influence of environmental processes on the destruction of biological remains in a subtropical lagoonal setting by describing the taphonomic signatures occurring in the mollusk shells from the Tramandaí Lagoon, northeastern Rio Grande do Sul State; and (ii) to compare living assemblages (LAs), death assemblages (DAs) and fossil assemblages (FAs) from estuaries and lagoons in the Rio Grande do Sul Coastal Plain to understand the nature and quality of biological information preserved in fossil associations in Holocene lagoon facies. Dissolution appears to be a leading taphonomic agent in lagoonal environments according to the study. The shells are within the taphonomically active zone and, due to intense dissolution, they will most likely leave no geological record. Nonetheless, the preservation of living species in FA was 100% and species present in DA are not as good preserved in recent (Holocene) fossil record as originally thought from the literature. The present results indicate that both DAs and FAs from estuarine-lagoons environments are composed basically by nonindigenous species, with live-dead mismatch than for continental shelves. The fidelity pattern here observed for estuarine mollusks have been driven by (i) high temporal and spatial variability in the LAs, (ii) spatial mixing in the DAs and (iii) differential preservation of shells, due to long residence times in the taphonomically active zone. Dissolution is the main taphonomic process altering biological information in those environments, but differential preservation may be, perhaps, the responsible for introducing bias from living to fossil assemblages.
106

Tafonomia de moluscos com ênfase em Sistemas Estuarino-Lagunares da Planície Costeira do Rio Grande do Sul, Brasil

Ritter, Matias do Nascimento January 2013 (has links)
Acumulações de restos de moluscos são muito comuns tanto em ambientes marinhos plataformais quanto em depósitos lagunares e estuarinos da América do Sul, principalmente entre o Brasil e a Argentina. A formação destas concentrações conchíferas pode prover grande oportunidade para estudos tafonômicos, os quais ainda são raros nesta região. Existem ainda questões a serem respondidas, por exemplo, quanta informação biológica está preservada nestas concentrações? Ou, qual é a probabilidade de uma associação viva deixar um registro fóssil análogo? Os principais objetivos deste estudo foram: (i) investigar a influência dos processos ambientais na destruição de remanescentes biológicos, através da descrição das assinaturas tafonômicas presentes em conchas de moluscos de dois afloramentos da Laguna Tramandaí, nordeste do Rio Grande do Sul; e (ii) testar o potencial de preservação de associações de moluscos vivos, mortos e fósseis de lagunas e estuários da Planície Costeira do Rio Grande do Sul, com o intuito de compreender a qualidade da informação biológica preservada nestas associações fósseis de fácies lagunares holocênicas. O principal processo tafonômico é a dissolução. As conchas estão inseridas na zona tafonomicamente ativa e experimentam intensa dissolução, o que reduz a probabilidade de deixarem um registro fóssil. Todavia, a preservação de espécies da associação viva nos depósitos fósseis foi de 100% em nível regional, e as espécies presentes na associação morta não apresentaram boa preservação no registro fóssil recente (Holoceno), ao contrário do que é usualmente predito na bibliografia. Isso indica que a associação morta é enriquecida por espécies não indígenas, e parte deste aumento relativo da riqueza é transferida para a associação fóssil. O padrão observado na fidelidade de moluscos estuarinos é ocasionado pela (i) alta variabilidade temporal e espacial nas associações vivas, (ii) mistura espacial nas associação mortas e (iii) preservação diferencial, devido à destruição durante uma longa permanência na zona tafonomicamente ativa. Portanto, a dissolução é o principal processo tafonômico que altera a informação biológica em ambientes transicionais, embora a preservação seletiva possa introduzir vieses das associações vivas às fósseis. / Molluscan shell accumulations (shell beds) are very common in shallow marine and estuarine environments in South America and also on the continental shelf from Southern Brazil through Argentina. The development of these shell beds can provide a great opportunity to taphonomic studies, which are uncommon in this geographic location. For example, how much biological information is preserved within these shell beds? Or, what is the actual probability a local living community has to leave a fossil record corresponding to these shell deposits? The aims of this study are (i) to investigate the influence of environmental processes on the destruction of biological remains in a subtropical lagoonal setting by describing the taphonomic signatures occurring in the mollusk shells from the Tramandaí Lagoon, northeastern Rio Grande do Sul State; and (ii) to compare living assemblages (LAs), death assemblages (DAs) and fossil assemblages (FAs) from estuaries and lagoons in the Rio Grande do Sul Coastal Plain to understand the nature and quality of biological information preserved in fossil associations in Holocene lagoon facies. Dissolution appears to be a leading taphonomic agent in lagoonal environments according to the study. The shells are within the taphonomically active zone and, due to intense dissolution, they will most likely leave no geological record. Nonetheless, the preservation of living species in FA was 100% and species present in DA are not as good preserved in recent (Holocene) fossil record as originally thought from the literature. The present results indicate that both DAs and FAs from estuarine-lagoons environments are composed basically by nonindigenous species, with live-dead mismatch than for continental shelves. The fidelity pattern here observed for estuarine mollusks have been driven by (i) high temporal and spatial variability in the LAs, (ii) spatial mixing in the DAs and (iii) differential preservation of shells, due to long residence times in the taphonomically active zone. Dissolution is the main taphonomic process altering biological information in those environments, but differential preservation may be, perhaps, the responsible for introducing bias from living to fossil assemblages.
107

Índices de referência para apoio na precificação da cama de aviário como fertilizante / Rates of reference to support the pricing of the birds bed as fertilizer

Metzner, Cláudio Marcos 18 December 2014 (has links)
Made available in DSpace on 2017-07-10T17:44:31Z (GMT). No. of bitstreams: 1 Claudio_Marcos_Metzner.pdf: 1253028 bytes, checksum: c662af6172282a4b707bf70ce4a721b4 (MD5) Previous issue date: 2014-12-18 / Data indicate that Brazil imports on average 75% of the nutrients that make up the base of mineral fertilizers. This implies that there is a moderate correlation in prices of mineral fertilizers with the Dollar. Also, it appears that Brazil is the fourth-largest producer of broilers, demonstrating that there is a large volume of waste generation in this activity, which could be used as corn fertilizer and the farmer can sell the bed of avian. Thereby we seek to answer the research questions: How to determine the price of poultry litter from their nutrients? And how to determine which is the best option in economic terms, of fertilization with avian or mineral bed, to the farmer who plans corn? Thus, the aim of this research was to establish benchmarks for pricing support in the aviary as fertilizer bed. The results show that there is a moderate correlation between the prices of poultry litter, corn and the dollar and the selling price of the poultry litter, from its fertilizer value oscillates between US $ 85 and $ 140 to tonne and that from the productivity of organic fertilization x mineral, it was elaborated arate of reference a benchmark, demonstrating that for the organic fertilizer, poultry litter, is the best option for the farmer who plans corn, in financial terms, considering prices and productivity, the market price in the poultry litter should be over 15% of the price of mineral fertilizer, with formulation 8-20-20 / Dados apontam que o Brasil importa em média 75% dos nutrientes que compõem a base dos fertilizantes minerais. Isso implica que há uma correlação moderada dos preços dos adubos minerais com o Dólar. Também, verifica-se que o Brasil situa-se como quarto maior produtor mundial de frangos de corte, demonstrando que existe grande volume de geração de resíduos nesta atividade, que poderia ser aproveitado como adubação do milho e o avicultor pode comercializar a cama de aviário. Desta forma buscou-se responder as perguntas da pesquisa: Como determinar o preço da cama de aviário a partir de seus nutrientes? E como determinar qual é a melhor opção, em termos econômicos, de adubação, com cama de aviário ou mineral, para o agricultor que planta milho? Assim, objetivou-se com esta pesquisa estabelecer índices de referência para apoio na precificação da cama de aviário como fertilizante. Os resultados encontrados demonstram que existe uma correlação moderada entre os preços da cama de aviário, o milho e o dólar e que o preço de venda da cama de aviário, a partir do seu valor fertilizante, oscila entre U$ 85 e U$ 140 a tonelada e que a partir da produtividade da adubação orgânica x mineral, elaborou-se um índice de referência, demonstrando que para que o adubo orgânico, cama de aviário, seja a melhor opção para o agricultor que planta milho, em termos financeiros, considerando preços e produtividades, o preço de mercado da cama de aviário não deve ser superior a 15% do preço do adubo mineral, com formulação 8-20-20
108

Distribution of Parasitic Isopods on Caridean Shrimp in South Florida Seagrass Beds

Briggs, Sarah A. 01 July 2013 (has links)
Caridean shrimp are a prominent element of seagrass faunal communities and play an important role in the energy transfer between trophic levels. They are a food source for other organisms and play an integral role in the ecosystem by feeding on algae and assisting with the breakdown of organic matter. Carideans are also fundamental to the marine fishery industry in that they are a food source for potentially valuable juvenile commercial fish. Ectoparasitic isopods (Cymothoida: Bopyridae) that infest caridean shrimps decrease the energy level of the shrimp, resulting in slower reaction time, greater predation rate, slower growth rate, and/or reduced egg production. However, in South Florida, little is known about the distributions and effects of parasitism among caridean shrimp in seagrass habitats. This research investigates the relationship of caridean shrimps and ectoparasitic isopods throughout several marine and brackish basins of coastal South Florida ranging from Lostmans River on the lower southwest mangrove coast through Florida Bay and Biscayne Bay. Samples were collected at the end of the wet season in 2010 and the dry season in 2011 using a 1-m2 throw-trap. Relations among isopods, carideans and environment were determined based on a series of biotic (host preference and availability) and abiotic (salinity, temperature, turbidity, water depth) factors. Bopyrid isopods were most abundant in Manatee Bay and Barnes Sound adjacent to the C-111 canal located in southern Biscayne Bay region and predominantly associated with Hippolyte spp. Logistical regression revealed that the likelihood of parasite presence is associated with higher temperatures, lower salinity, increasing depth, less seagrass coverage and greater macroalgae coverage. The results suggest that increased stressors in an environment, such as anthropogenic runoff, may also negatively impact host resistance to parasitism.
109

Thermal energy storage for nuclear power applications

Edwards, Jacob N. January 1900 (has links)
Master of Science / Department of Mechanical and Nuclear Engineering / Hitesh Bindra / Storing excess thermal energy in a storage media that can later be extracted during peak-load times is one of the better economical options for nuclear power in future. Thermal energy storage integration with light water-cooled and advanced nuclear power plants is analyzed to assess technical feasibility of different storage media options. Various choices are considered in this study; molten salts, synthetic heat transfer fluids, and packed beds of solid rocks or ceramics. In-depth quantitative assessment of these integration possibilities are then analyzed using exergy analysis and energy density models. The exergy efficiency of thermal energy storage systems is quantified based on second law thermodynamics. The packed bed of solid rocks is identified as one of the only options which can be integrated with upcoming small modular reactors. Directly storing thermal energy from saturated steam into packed bed of rocks is a very complex physical process due to phase transformation, two phase flow in irregular geometries and percolating irregular condensate flow. In order to examine the integrated physical aspects of this process, the energy transport during direct steam injection and condensation in the dry cold randomly packed bed of spherical alumina particles was experimentally and theoretically studied. This experimental setup ensures controlled condensation process without introducing significant changes in the thermal state or material characteristics of heat sink. Steam fronts at different flow rates were introduced in a cylindrical packed bed and thermal response of the media was observed. The governing heat transfer modes in the media are completely dependent upon the rate of steam injection into the system. A distinct differentiation between the effects of heat conduction and advection in the bed were observed with slower steam injection rates. A phenomenological semi-analytical model is developed for predicting quantitative thermal behavior of the packed bed and understanding physics. The semi-analytical model results are compared with the experimental data for the validation purposes. The steam condensation process in packed beds is very stable under all circumstances and there is no effect of flow fluctuations on thermal stratification in packed beds. With these experimental and analytical studies, it can be concluded that packed beds have potential for thermal storage applications with steam as heat transfer fluid. The stable stratification and condensation process in packed beds led to design of a novel passive safety heat removal system for advanced boiling water reactors.
110

Hydrodynamics, stability and scale-up of slot-rectangular spouted beds

Chen, Zhiwei 05 1900 (has links)
Slot-rectangular spouted beds, with rectangular cross-section and slotted gas inlets, have been proposed as a solution to overcoming scale-up difficulties with conventional axisymmetric spouted beds. They can be utilized in gas/particle processes such as drying of coarse particles and coating of tablets. However, application of this spouted bed was limited because of instability and insufficient hydrodynamic studies. The present work is therefore aimed at the study of hydrodynamics, stability and scale-up of slot-rectangular spouted beds. The hydrodynamic study was carried out in four slot-rectangular columns of various width-to-thickness ratios combined with various slot configurations, particles of different properties and a range of operating conditions. Hydrodynamics of slot-rectangular spouted beds showed major similarity with conventional spouted beds. However, equations and mechanistic models adopted from conventional axisymmetric spouted beds generally failed to provide good predictions for the three-dimensional slot-rectangular geometry. New empirical correlations were derived for the minimum spouting velocity and maximum pressure drop for different slot configurations. Slot-rectangular spouted beds also showed more flow regimes than conventional spouted beds. Nine flow regimes, as well as unstable conditions, were identified based on frequency and statistical analysis of pressure fluctuations. Slot geometrical configuration was found to be the main factor affecting the stability of slot-rectangular spouted beds. A comprehensive hydrodynamic study on the effect of slot configuration was therefore carried out. Slots of smaller length-to-width ratio, smaller length and greater depth were found to provide greater stability. Stable criteria for the slot configuration were found consistent with the conventional axisymmetric spouted beds with extra limitation on slot length-to-width ratio and slot depth. Local distributions of pressure, particle velocity and voidage, as well as spout shape and particle circulating flux, were compared for different slot configurations. Higher slot length-to-width ratios lead to slightly higher particle circulation rates. A previously proposed scale-up method involving multiple chambers was tested in the present work using multiple slots. Instability caused by the merging of multiple spouts and asymmetric flow was successfully prevented by suspending vertical partitions between the fountains. Some criteria and guidelines were also proposed for scale-up using multiple chambers. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Page generated in 0.057 seconds