990 resultados para load reduction
Resumo:
The impact of urban waste-water and non-point nitrate discharges in estuarine and near-shore coastal waters are analyzed. The study is focused on the effects of applying the European directives 91/271/EEC and 91/676/EEC to these systems. 4 Portuguese estuaries and two coastal lagoons with different characteristics are studied. A modelling system is applied and calibrated in each system. Three nitrate load scenarios are examined. It is shown that the morphologic and hydrodynamic characteristics of the domain largely control the ecological processes in these systems. The primary production limitation factors are split into “biologic” and “hydrodynamic” components. The physical limitation due to hydrodynamic and residence time is the most important factor. The combined limitation of “biologic” factors (temperature, light and nutrients availability) control productivity only in the systems where physical limitation is not important.
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The Chesapeake Bay is the largest estuary in the United States supporting a complex ecosystem that sustains many habitats and the organisms that depend on them. The bay also supports economic, recreational, and cultural activities to over 16 million people residing in the watershed. Changes within the watershed have caused excessive levels of nutrients, mainly nitrogen and phosphorous, to pollute the bay. The Chesapeake Bay Program, guided by a complex agreement, was created to address these and other issues and oversee the restoration of the bay. The most recent version of this agreement, the Chesapeake 2000, declares its continued commitment to restore the bay with over 100 goals to be met by the year 2010. Reports show that although intensive efforts have been made to promote nutrient reduction, very little reduction has actually resulted. This project described these efforts. The final results reveal obstacles affecting progress, shortcomings to current approaches and possible solutions for future implementation.
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This paper reports the impact on confinement and power load of the high-shape 2.5 MA ELMy H-mode scenario at JET of a change from all carbon plasma-facing components to an all metal wall. In preparation to this change, systematic studies of power load reduction and impact on confinement as a result of fuelling in combination with nitrogen seeding were carried out in JET-C and are compared with their counterpart in JET with a metallic wall. An unexpected and significant change is reported on the decrease in the pedestal confinement but is partially recovered with the injection of nitrogen.
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Water Sensitive Urban Design (WSUD) systems have the potential mitigate the hydrologic disturbance and water quality concerns associated with stormwater runoff from urban development. In the last few years WSUD has been strongly promoted in South East Queensland (SEQ) and new developments are now required to use WSUD systems to manage stormwater runoff. However, there has been limited field evaluation of WSUD systems in SEQ and consequently knowledge of their effectiveness in the field, under storm events, is limited. The objective of this research project was to assess the effectiveness of WSUD systems installed in a residential development, under real storm events. To achieve this objective, a constructed wetland, bioretention swale and a bioretention basin were evaluated for their ability to improve the hydrologic and water quality characteristics of stormwater runoff from urban development. The monitoring focused on storm events, with sophisticated event monitoring stations measuring the inflow and outflow from WSUD systems. Data analysis undertaken confirmed that the constructed wetland, bioretention basin and bioretention swale improved the hydrologic characteristics by reducing peak flow. The bioretention systems, particularly the bioretention basin also reduced the runoff volume and frequency of flow, meeting key objectives of current urban stormwater management. The pollutant loads were reduced by the WSUD systems to above or just below the regional guidelines, showing significant reductions to TSS (70-85%), TN (40-50%) and TP (50%). The load reduction of NOx and PO4 3- by the bioretention basin was poor (<20%), whilst the constructed wetland effectively reduced the load of these pollutants in the outflow by approximately 90%. The primary reason for the load reduction in the wetland was due to a reduction in concentration in the outflow, showing efficient treatment of stormwater by the system. In contrast, the concentration of key pollutants exiting the bioretention basin were higher than the inflow. However, as the volume of stormwater exiting the bioretention basin was significantly lower than the inflow, a load reduction was still achieved. Calibrated MUSIC modelling showed that the bioretention basin, and in particular, the constructed wetland were undersized, with 34% and 62% of stormwater bypassing the treatment zones in the devices. Over the long term, a large proportion of runoff would not receive treatment, considerably reducing the effectiveness of the WSUD systems.
Resumo:
Constructed wetlands are a common structural treatment measure employed to remove stormwater pollutants and forms an important part of the Water Sensitive Urban Design (WSUD) treatment suite. In a constructed wetland, a range of processes such as settling, filtration, adsorption, and biological uptake play a role in stormwater treatment. Occurrence and effectiveness of these processes are variable and influenced by hydraulic, chemical and biological factors. The influence of hydraulic factors on treatment processes are of particular concern. This paper presents outcomes of a comprehensive study undertaken to define the treatment performance of a constructed wetland highlighting the influence of hydraulic factors. The study included field monitoring of a well established constructed wetland for quantity and quality factors, development of a conceptual hydraulic model to simulate water movement within the wetland and multivariate analysis of quantity and quality data to investigate correlations and to define linkages between treatment performance and influential hydraulic factors. Total Suspended Solids (TSS), Total Nitrogen (TN) and Total Phosphorus (TP) concentrations formed the primary pollutant parameters investigated in the data analysis. The outcomes of the analysis revealed significant reduction in event mean concentrations of all three pollutants species. Treatment performance of the wetland was significantly different for storm events above and below the prescribed design event. For events below design event, TSS and TN load reduction was comparatively high and strongly influenced by high retention time. For events above design event, TP load reduction was comparatively high and was found to be influenced by the characteristics of TP wash-off from catchment surfaces.
Resumo:
Performance of a constructed wetland is commonly reported as variable due to the site specific nature of influential factors. This paper discusses outcomes from an in-depth study which characterised treatment performance of a wetland based on the variation in runoff regime. The study included a comprehensive field monitoring of a well established constructed wetland in Gold Coast, Australia. Samples collected at the inlet and outlet was tested for Total Suspended Solids (TSS), Total Nitrogen (TN) and Total Phosphorus (TP). Pollutant concentrations in the outflow were found to be consistent irrespective of the variation in inflow water quality. The analysis revealed two different treatment characteristics for events with different rainfall depths. TSS and TN load reduction is strongly influenced by hydraulic retention time where performance is higher for rainfall events below the design event. For small events, treatment performance is higher at the beginning of the event and gradually decreased during the course of the event. For large events, the treatment performance is comparatively poor at the beginning and improved during the course of the event. The analysis also confirmed the variable treatment trends for different pollutant types.
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This paper reviews electricity consumption feedback literature to explore the potential of electricity feedback to affect residential consumers’ electricity usage patterns. The review highlights a substantial amount of literature covering the debate over the effectiveness of different feedback criteria to residential customer acceptance and overall conservation and peak demand reduction. Researchers studying the effects of feedback on everyday energy use have observed substantial variation in effect size, both within and between studies. Although researchers still continue to question the types of feedback that are most effective in encouraging conservation and peak load reduction, some trends have emerged. These include that feedback be received as quickly as possible to the time of consumption; be related to a standard; be clear and meaningful and where possible both direct and indirect feedback be customised to the customer. In general, the literature finds that feedback can reduce electricity consumption in homes by 5 to 20 per cent, but that significant gaps remain in our knowledge of the effectiveness and cost benefit of feedback.
Resumo:
A ecologia de reservatórios, que são ecossistemas complexos, dinâmicos e artificiais, vem assumindo destaque no Brasil. O objetivo deste trabalho foi avaliar a viabilidade da aplicação, no reservatório de APM-Manso, de um modelo ecológico tridimensional em estudos sobre a dinâmica fitoplanctônica, simulando a variação temporal do fitoplâncton para cenários distintos de carga de nutrientes. O modelo CAEDYM foi acoplado ao ELCOM e simulação foi realizada em duas etapas: uma hidrodinâmica e outra ecológica. Escolheu-se para as simulações o período de cinco meses, a partir de 1 de setembro de 2005. Foram construídos dois cenários de simulação, o primeiro contendo os valores reais de carga de nutrientes dos principais rios contribuintes medidos em campo, e o segundo com redução na carga nutricional destes rios, simulando um possível processo de substituição de áreas florestadas por áreas de pastagem na bacia do rio Manso. A comunidade fitoplanctônica simulada apresentou rápidas respostas à disponibilidade nutricional do ambiente, e os resultados obtidos corroboraram com diversas teorias sobre as estratégias adaptativas e sobre as dinâmicas algais. Dentre as classes simuladas, Bacillariophyceae e Cryptophyceae se mostraram mais sensíveis às reduções de carga, enquanto Chrolophyceae e Cyanophyceae, apesar de terem suas biomassas reduzidas, sofreram menos com o impacto, sugerindo estarem mais adaptadas à limitação de nutrientes. Os picos chuvosos influenciaram positivamente as taxas de crescimento das Bacillariophyceae apenas no Cenário 1, uma vez que a limitação por nutrientes foi mais decisiva para esta classe no Cenário 2. Observou-se em ambas as simulações uma tendência de substituição na dominância de Cyanophyceae por Chlorophyceae.
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A hanseníase é uma doença infecciosa causada pelo Mycobacteruim leprae, um bacilo intracelular obrigatório, que prolifera principalmente na pele e nos nervos periféricos no interior de células como macrófagos e células de Schwann. A transmissão ocorre por meio das mucosas das vias respiratórias, provavelmente por aerossóis expelidos por indivíduos infectados. O homem é o seu hospedeiro natural sendo a multiplicação do bacilo muito lenta, com um período de geração estimado de 14 dias. Apesar da mínima variação no genoma do M. leprae, a doença é caracterizada por um espectro de formas clínicas bem definido, decorrente da capacidade de resposta imune do hospedeiro. Em pacientes classificados como multibacilares (MB) a doença é disseminada, com inúmeras lesões de pele e proliferação bacilar considerável. Nesses indivíduos ocorre hiporresponsividade celular ao M. leprae. Nas formas paucibacilares (PB), os pacientes apresentam uma ou poucas lesões, a carga bacilar é pequena e, às vezes não observada por meio da baciloscopia tradicional e ocorre resposta imune patógeno-específica. As incapacidades físicas nos pacientes decorrem da neuropatia e osteopatia e podem ser irreversíveis. Essas deformidades podem avançar mesmo após a diminuição da carga bacilar com o final do tratamento poliquimioterápico. A presente tese teve por objetivo estudar as implicações da proteína PHEX nas alterações fisiopatológicas da hanseníase, em especial as alterações ósseas. A proteína PHEX (Phosphate-regulating gene with Homologies to Endopeptidase on the X chromosome) é expressa em várias células humanas e, no primeiro artigo que compõe essa tese, demonstramos que o M.leprae leva à diminuição da expressão de PHEX em linhagens de células de Schwann e osteoblastos humanos. Este efeito foi igualmente causado por outras espécies de micobactérias. No segundo manuscrito ora submetido, observamos que em leucócitos sanguíneos de pacientes hansenianos também ocorreu modulação negativa de PHEX. Este efeito não se relacionou com a capacidade de produção de citocinas inflamatórias frente ao M. leprae in vitro ou com alterações bioquímicas. O efeito inibidor da mineralização ocasionado pela modulação negativa de PHEX talvez contribua para a doença óssea da hanseníase, auxiliando a explicar a capacidade do M. leprae de penetrar e sobreviver no osso.
Resumo:
Pile jacking is a common installation method for displacement piles due to the low noise and vibration involved in the installation procedure. Problems may occur when modelling jacked piles in the centrifuge, especially for friction piles, due to scaling effects which can be minimised, provided that the pile diameter is greater than fifty times the mean grain size. A series of centrifuge tests of jacked piles was performed in both dry and saturated fine sand. Piles were installed using three different methods. The effect of the installation method on the head load required is assessed. The influence of the normalised roughness was also tested by testing one rough and one smooth pile. Finally, cyclic shearing at constant depth was performed to establish the shaft load reduction due to friction fatigue. © 2014 Taylor & Francis Group.
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This paper reports the progress made at JET-ILW on integrating the requirements of the reference ITER baseline scenario with normalized confinement factor of 1, at a normalized pressure of 1.8 together with partially detached divertor whilst maintaining these conditions over many energy confinement times. The 2.5 MA high triangularity ELMy H-modes are studied with two different divertor configurations with D-gas injection and nitrogen seeding. The power load reduction with N seeding is reported. The relationship between an increase in energy confinement and pedestal pressure with triangularity is investigated. The operational space of both plasma configurations is studied together with the ELM energy losses and stability of the pedestal of unseeded and seeded plasmas. The achievement of stationary plasma conditions over many energy confinement times is also reported.
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In competitive electricity markets with deep concerns for the efficiency level, demand response programs gain considerable significance. As demand response levels have decreased after the introduction of competition in the power industry, new approaches are required to take full advantage of demand response opportunities. This paper presents DemSi, a demand response simulator that allows studying demand response actions and schemes in distribution networks. It undertakes the technical validation of the solution using realistic network simulation based on PSCAD. The use of DemSi by a retailer in a situation of energy shortage, is presented. Load reduction is obtained using a consumer based price elasticity approach supported by real time pricing. Non-linear programming is used to maximize the retailer’s profit, determining the optimal solution for each envisaged load reduction. The solution determines the price variations considering two different approaches, price variations determined for each individual consumer or for each consumer type, allowing to prove that the approach used does not significantly influence the retailer’s profit. The paper presents a case study in a 33 bus distribution network with 5 distinct consumer types. The obtained results and conclusions show the adequacy of the used methodology and its importance for supporting retailers’ decision making.
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The need for heating and cooling in buildings constitutes a considerable part of the total energy use in a country and reducing this need is of outmost importance in order to reach national and international goals for reducing energy use and emissions. One important way of reaching these goals is to increase the proportion of renewable energy used for heating and cooling of buildings. Perhaps the largest obstacle with this is the often occurring mismatch between the availability of renewable energy and the need for heating or cooling, hindering this energy to be used directly. This is one of the problems that can be solved by using thermal energy storage (TES) in order to save the heat or cold from when it is available to when it is needed. This thesis is focusing on the combination of TES techniques and buildings to achieve increased energy efficiency for heating and cooling. Various techniques used for TES as well as the combination of TES in buildings have been investigated and summarized through an extensive literature review. A survey of the Swedish building stock was also performed in order to define building types common in Sweden. Within the scope of this thesis, the survey resulted in the selection of three building types, two single family houses and one office building, out of which the two residential buildings were used in a simulation case study of passive TES with increased thermal mass (both sensible and latent). The second case study presented in the thesis is an evaluation of an existing seasonal borehole storage of solar heat for a residential community. In this case, real measurement data was used in the evaluation and in comparisons with earlier evaluations. The literature reviews showed that using TES opens up potential for reduced energy demand and reduced peak heating and cooling loads as well as possibilities for an increased share of renewable energy to cover the energy demand. By using passive storage through increased thermal mass of a building it is also possible to reduce variations in the indoor temperature and especially reduce excess temperatures during warm periods, which could result in avoiding active cooling in a building that would otherwise need it. The analysis of the combination of TES and building types confirmed that TES has a significant potential for increased energy efficiency in buildings but also highlighted the fact that there is still much research required before some of the technologies can become commercially available. In the simulation case study it was concluded that only a small reduction in heating demand is possible with increased thermal mass, but that the time with indoor temperatures above 24 °C can be reduced by up to 20%. The case study of the borehole storage system showed that although the storage system worked as planned, heat losses in the rest of the system as well as some problems with the system operation resulted in a lower solar fraction than projected. The work presented within this thesis has shown that TES is already used successfully for many building applications (e.g. domestic hot water stores and water tanks for storing solar heat) but that there still is much potential in further use of TES. There are, however, barriers such as a need for more research for some storage technologies as well as storage materials, especially phase change material storage and thermochemical storage.
Resumo:
The fucose mannose ligand (Leishmania donovani FML)-saponin vaccine has earlier shown its immunoprophylactic potential against visceral leishmaniasis in the CB hamster (87.7% of parasite load reduction), Balb/c (84.4%) and Swiss albino mouse (85-93%) models. In this investigation its specific immunotherapeutic efficacy against L. donovani infection in Balb/c mice was studied. The effects of vaccine treatment on the Immoral response, delayed type of hypersensitivity to promastigote lysate (DTH), cytokine levels in sera and reduction of the liver parasitic load of L. donovani infected mice, were examined. The types and subtypes of anti-FML antibodies increased significantly in the vaccinees over the saline and saponin controls. As expected for a saponin vaccine, the highest ratios were found in relation to IgG1, IgG2a and IgG2b (4.4, 5 and 2.5, respectively). The DTH response and the in vitro ganglion cell proliferative response against FML antigen were also significantly higher than controls (P < 0.005). Concomitantly, an impressive and specific decrease of liver parasitic burden was detected only in vaccine-treated animals (94.7%). Our results indicate that the therapeutic FML-vaccine has a potent effect on modulation of the murine infection leading to the reduction of parasitic load and signs of disease, being a new potential tool in the therapy and control of visceral leishmaniasis. (C) 2003 Elsevier Ltd. All rights reserved.
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This paper describes an innovative approach to establish a CS curriculum, aiming flexibility and minimization of the time spent in the classrooms. This approach has been developed at the Paulista State University - Unesp - at São José do Rio Preto, and is producing very interesting results. The load reduction is achieved through a series of fundamental core and breadth courses that precede depth courses in specific areas. The flexibility comes as a side effect of the depth courses, which can be adapted without any changes in the core courses. In the following pages we fully describe our motivations, actions and results.