915 resultados para Ambient pressures
Resumo:
At present, photovoltaic energy is one of the most important renewable energy sources. The demand for solar panels has been continuously growing, both in the industrial electric sector and in the private sector. In both cases the analysis of the solar panel efficiency is extremely important in order to maximize the energy production. In order to have a more efficient photovoltaic system, the most accurate understanding of this system is required. However, in most of the cases the only information available in this matter is reduced, the experimental testing of the photovoltaic device being out of consideration, normally for budget reasons. Several methods, normally based on an equivalent circuit model, have been developed to extract the I-V curve of a photovoltaic device from the small amount of data provided by the manufacturer. The aim of this paper is to present a fast, easy, and accurate analytical method, developed to calculate the equivalent circuit parameters of a solar panel from the only data that manufacturers usually provide. The calculated circuit accurately reproduces the solar panel behavior, that is, the I-V curve. This fact being extremely important for practical reasons such as selecting the best solar panel in the market for a particular purpose, or maximize the energy extraction with MPPT (Maximum Peak Power Tracking) methods.
Resumo:
Within the technological framework of Information and Communication Technologies (ICT), consumers are currently requesting multimedia services with simplicity of use, reliability, security and service availability through mobile and fixed access. Network operators are proposing the Next Generation Networks (NGN) to address the challenges of providing both services and network convergence. Apart from these considerations, there is a need to provide social and healthcare assistance services in order to support the progressive aging in the elderly population. In order to achieve this objective, the Ambient Assisted Living (AAL) initiative proposes ICT systems and services to promote autonomy and an independent life among the elderly. This paper describes the design and implementation of a group of services, called “service enablers”, which helps AAL applications to be supported in NGN. The presented enablers are identified to support the teleconsulting applications requirements in an NGN environment, involving the implementation of a virtual waiting room, a virtual whiteboard, a multimedia multiconference and a vital-signs monitoring presence status. A use case is defined and implemented to evaluate the developed enablers' performance.
Resumo:
An approximate procedure for studying harmonic soil-structure interaction problems is presented. The presence of Rayleigh waves is considered and the resulting governing equations of the dynamic soil-structure system are solved in the time domain. With this method the transient and steady states of a vibratory motion and also the nonlinear behaviour of the soil can be studied. As an example, the dynamic earth pressure against a rigid retaining wall is investigated. The loads are assumed to be harmonic Rayleigh waves with both static and dynamic surface surcharges. The dependence of the results on the excitation frequency is shown.
Resumo:
Human activity attracting a lot of research activity in several fields including the use of wireless sensors, positioning technologies and techniques, embedded computing, remote sensing and energy management among others. There are a number of applications where the results of those investigations can be applied, including ambient intelligence to support human activity, particularly the elderly and disabled people. Ambient intelligence is a new paradigm for the information and communications technologies where the electronic/digital environment takes care of the people presence and their needs, becoming an active, adaptive and responsive environment.
Resumo:
As environmental standards become more stringent (e.g. European Directive 2008/50/EC), more reliable and sophisticated modeling tools are needed to simulate measures and plans that may effectively tackle air quality exceedances, common in large cities across Europe, particularly for NO2. Modeling air quality in urban areas is rather complex since observed concentration values are a consequence of the interaction of multiple sources and processes that involve a wide range of spatial and temporal scales. Besides a consistent and robust multi-scale modeling system, comprehensive and flexible emission inventories are needed. This paper discusses the application of the WRF-SMOKE-CMAQ system to the Madrid city (Spain) to assess the contribution of the main emitting sectors in the region. A detailed emission inventory was compiled for this purpose. This inventory relies on bottom-up methods for the most important sources. It is coupled with the regional traffic model and it makes use of an extensive database of industrial, commercial and residential combustion plants. Less relevant sources are downscaled from national or regional inventories. This paper reports the methodology and main results of the source apportionment study performed to understand the origin of pollution (main sectors and geographical areas) and define clear targets for the abatement strategy. Finally the structure of the air quality monitoring is analyzed and discussed to identify options to improve the monitoring strategy not only in the Madrid city but the whole metropolitan area.
Resumo:
Esta memoria es el resultado de un proyecto cuyo objetivo ha sido realizar un análisis de la posible aplicación de técnicas relativas al Process Mining para entornos AmI (Ambient Intelligence). Dicho análisis tiene la facultad de presentar de forma clara los resultados extraídos de los procesos relativos a un caso de uso planteado, así como de aplicar dichos resultados a aplicaciones relativas a entornos AmI, como automatización de tareas o simulación social basada en agentes. Para que dicho análisis sea comprensible por el lector, se presentan detalladas explicaciones de los conceptos tratados y las técnicas empleadas. Además, se analizan exhaustivamente las dos herramientas software más utilizadas en cuanto a minería de procesos se refiere, ProM y Disco, presentando ventajas e inconvenientes de cada una, así como una comparación entre las dos. Posteriormente se ha desarrollado una metodología para el análisis de procesos con la herramienta ProM, anteriormente mencionada, explicando cuidadosamente cada uno de los pasos así como los fundamentos de los algoritmos utilizados. Por último, se han presentado las conclusiones extraídas del trabajo, así como las posibles líneas de continuación del proyecto.
Resumo:
O contexto atual das organizações é permeado por pressões, crises e incertezas, características da era da globalização, que requer capacidade humana para adaptações. O enfrentamento constante às situações instáveis necessita, em qualquer nível relacional, do que se tem nomeado resiliência. Atualmente, o uso deste termo vem se expandindo devido à sua aplicabilidade no estudo da capacidade humana de resistir à situação de intensa pressão. O termo resiliência foi desenvol vido a partir de estudos de população em estado de risco e vulnerabilidade, e atualmente tem pautado algumas discussões no campo organizacional. Com base neste conceito, objetiva -se, neste trabalho, estudar a resiliência em gestores de pessoas, em uma organização de grande porte com fins lucrativos, da área de Serviços em São Paulo, a partir da aplicação do Questionário do Índice de Resiliência: Adultos - Reivich-Shatté/Barbosa (2006). A metodologia de pesquisa adotada é de cunho exploratório e descritivo. O instrumento utilizado propiciou mensurar os sete fatores constitutivos da resiliência no comportamento humano, sendo eles: administração das emoções, controle de impulsos, otimismo com a vida, aná lise do ambiente, empatia, auto-eficácia e alcançar as pessoas. Os resultados obtidos demonstram que é possível estudar a resiliência em gestores de pessoas, a partir da utilização do instrumento proposto. Este trabalho permitiu também associar os fatores que constituem a resiliência a algumas competências essenciais necessárias para o gestor de pessoas realizar adequadamente suas atividades, sem negligenciar os aspectos de liderança associados à sua atuação.(AU)
Resumo:
O contexto atual das organizações é permeado por pressões, crises e incertezas, características da era da globalização, que requer capacidade humana para adaptações. O enfrentamento constante às situações instáveis necessita, em qualquer nível relacional, do que se tem nomeado resiliência. Atualmente, o uso deste termo vem se expandindo devido à sua aplicabilidade no estudo da capacidade humana de resistir à situação de intensa pressão. O termo resiliência foi desenvol vido a partir de estudos de população em estado de risco e vulnerabilidade, e atualmente tem pautado algumas discussões no campo organizacional. Com base neste conceito, objetiva -se, neste trabalho, estudar a resiliência em gestores de pessoas, em uma organização de grande porte com fins lucrativos, da área de Serviços em São Paulo, a partir da aplicação do Questionário do Índice de Resiliência: Adultos - Reivich-Shatté/Barbosa (2006). A metodologia de pesquisa adotada é de cunho exploratório e descritivo. O instrumento utilizado propiciou mensurar os sete fatores constitutivos da resiliência no comportamento humano, sendo eles: administração das emoções, controle de impulsos, otimismo com a vida, aná lise do ambiente, empatia, auto-eficácia e alcançar as pessoas. Os resultados obtidos demonstram que é possível estudar a resiliência em gestores de pessoas, a partir da utilização do instrumento proposto. Este trabalho permitiu também associar os fatores que constituem a resiliência a algumas competências essenciais necessárias para o gestor de pessoas realizar adequadamente suas atividades, sem negligenciar os aspectos de liderança associados à sua atuação.(AU)
Resumo:
Nitric oxide produced in endothelial cells affects vascular tone. To investigate the role of endothelial nitric oxide synthase (eNOS) in blood pressure regulation, we have generated mice heterozygous (+/−) or homozygous (−/−) for disruption of the eNOS gene. Immunohistochemical staining with anti-eNOS antibodies showed reduced amounts of eNOS protein in +/− mice and absence of eNOS protein in −/− mutant mice. Male or female mice of all three eNOS genotypes were indistinguishable in general appearance and histology, except that −/− mice had lower body weights than +/+ or +/− mice. Blood pressures tended to be increased (by approximately 4 mmHg) in +/− mice compared with +/+, while −/− mice had a significant increase in pressure compared with +/+ mice (≈18 mmHg) or +/− mice (≈14 mmHg). Plasma renin concentration in the −/− mice was nearly twice that of +/+ mice, although kidney renin mRNA was modestly decreased in the −/− mice. Heart rates in the −/− mice were significantly lower than in +/− or +/+ mice. Appropriate genetic controls show that these phenotypes in F2 mice are due to the eNOS mutation and are not due to sequences that might differ between the two parental strains (129 and C57BL/6J) and are linked either to the eNOS locus or to an unlinked chromosomal region containing the renin locus. Thus eNOS is essential for maintenance of normal blood pressures and heart rates. Comparisons between the current eNOS mutant mice and previously generated inducible nitric oxide synthase mutants showed that homozygous mutants for the latter differ in having unaltered blood pressures and heart rates; both are susceptible to lipopolysaccharide-induced death.
Resumo:
Earth’s biota produces vast quantities of polymerized silica at ambient temperatures and pressures by mechanisms that are not understood. Silica spicules constitute 75% of the dry weight of the sponge Tethya aurantia, making this organism uniquely tractable for analyses of the proteins intimately associated with the biosilica. Each spicule contains a central protein filament, shown by x-ray diffraction to exhibit a highly regular, repeating structure. The protein filaments can be dissociated to yield three similar subunits, named silicatein α, β, and γ. The molecular weights and amino acid compositions of the three silicateins are similar, suggesting that they are members of a single protein family. The cDNA sequence of silicatein α, the most abundant of these subunits, reveals that this protein is highly similar to members of the cathepsin L and papain family of proteases. The cysteine at the active site in the proteases is replaced by serine in silicatein α, although the six cysteines that form disulfide bridges in the proteases are conserved. Silicatein α also contains unique tandem arrays of multiple hydroxyls. These structural features may help explain the mechanism of biosilicification and the recently discovered activity of the silicateins in promoting the condensation of silica and organically modified siloxane polymers (silicones) from the corresponding silicon alkoxides. They suggest the possibility of a dynamic role of the silicateins in silicification of the sponge spicule and offer the prospect of a new synthetic route to silica and siloxane polymers at low temperature and pressure and neutral pH.
Resumo:
There has been a great deal of recent attention on the suspected increase in amphibian deformities. However, most reports of amphibian deformities have been anecdotal, and no experiments in the field under natural conditions have been performed to investigate this phenomenon. Under laboratory conditions, a variety of agents can induce deformities in amphibians. We investigated one of these agents, UV-B radiation, in field experiments, as a cause for amphibian deformities. We monitored hatching success and development in long-toed salamanders under UV-B shields and in regimes that allowed UV-B radiation. Embryos under UV-B shields had a significantly higher hatching rate and fewer deformities, and developed more quickly than those exposed to UV-B. Deformities may contribute directly to embryo mortality, and they may affect an individual’s subsequent survival after hatching.
Resumo:
Objective: To examine the possibility that low birth weight is a feature of the inherited predisposition to high blood pressure.
Resumo:
Chloroplast-targeted overexpression of an Fe superoxide dismutase (SOD) from Arabidopsis thaliana resulted in substantially increased foliar SOD activities. Ascorbate peroxidase, glutathione reductase, and monodehydroascorbate reductase activities were similar in the leaves from all of the lines, but dehydroascorbate reductase activity was increased in the leaves of the FeSOD transformants relative to untransformed controls. Foliar H2O2, ascorbate, and glutathione contents were comparable in all lines of plants. Irradiance-dependent changes in net CO2 assimilation and chlorophyll a fluorescence quenching parameters were similar in all lines both in air (21% O2) and at low (1%) O2. CO2-response curves for photosynthesis showed similar net CO2-exchange characteristics in all lines. In contrast, values of photochemical quenching declined in leaves from untransformed controls at intercellular CO2 (Ci) values below 200 μL L−1 but remained constant with decreasing Ci in leaves of FeSOD transformants. When the O2 concentration was decreased from 21 to 1%, the effect of FeSOD overexpression on photochemical quenching at limiting Ci was abolished. At high light (1000 μmol m−2 s−1) a progressive decrease in the ratio of variable (Fv) to maximal (Fm) fluorescence was observed with decreasing temperature. At 6oC the high-light-induced decrease in the Fv/Fm ratio was partially prevented by low O2 but values were comparable in all lines. Methyl viologen caused decreased Fv/Fm ratios, but this was less marked in the FeSOD transformants than in the untransformed controls. These observations suggest that the rate of superoxide dismutation limits flux through the Mehler-peroxidase cycle in certain conditions.
Resumo:
The ability of 21 C3 and C4 monocot and dicot species to rapidly export newly fixed C in the light at both ambient and enriched CO2 levels was compared. Photosynthesis and concurrent export rates were estimated during isotopic equilibrium of the transport sugars using a steady-state 14CO2-labeling procedure. At ambient CO2 photosynthesis and export rates for C3 species were 5 to 15 and 1 to 10 μmol C m−2 s−1, respectively, and 20 to 30 and 15 to 22 μmol C m−2 s−1, respectively, for C4 species. A linear regression plot of export on photosynthesis rate of all species had a correlation coefficient of 0.87. When concurrent export was expressed as a percentage of photosynthesis, several C3 dicots that produced transport sugars other than Suc had high efflux rates relative to photosynthesis, comparable to those of C4 species. At high CO2 photosynthetic and export rates were only slightly altered in C4 species, and photosynthesis increased but export rates did not in all C3 species. The C3 species that had high efflux rates relative to photosynthesis at ambient CO2 exported at rates comparable to those of C4 species on both an absolute basis and as a percentage of photosynthesis. At ambient CO2 there were strong linear relationships between photosynthesis, sugar synthesis, and concurrent export. However, at high CO2 the relationships between photosynthesis and export rate and between sugar synthesis and export rate were not as strong because sugars and starch were accumulated.