996 resultados para Agronomic efficiency


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The objective of this work was to evaluate the effect of doses of selenate and selenite on rice (Oryza sativa) biofortification with Se, as well the influence of these forms of Se in the levels of P, S, Fe, and Zn in grains. The experiment was conducted in a greenhouse, in pots with 4 dm(3) of a sandy clay loam Latosol, with medium texture, in a 5x2 factorial arrangement with five doses of Se (0, 0.75, 1.50, 3.0, and 6.0 mg dm(-3)) and two forms of Se (selenate and selenite). Selenate provided greater efficiency of root uptake of Se, plant-use efficiency, translocation from roots to shoots, and content of this element in rice grains. The application of Se during fertilization influences the levels of P, S, and Zn, but does not affect those of Fe in rice grains.

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Proper management of the N applied to crops is necessary in order to increase yield, improve water use efficiency (WUE) and reduce the pollutions risks with the least economic, environmental and health costs. A field study with melon crops was conducted during 2005, 2006 and 2007 in central Spain, using 11 different amounts of N. Some environmental indexes have been proposed, to provide an essential tool for determining the groundwater pollution risks associated with common agricultural practices. These indexes are related to variation in the nitrate concentration of drinking water (Impact Index (II)) and groundwater (Environmental Impact Index (EII)). Also, the Management Efficiency (ME) was calculated, which is related to the amount of fruit produced per gram of N leached (Nl). To determine the optimum dose of N, it was also necessary to know the N mineralisation (NM). Our results show that 160 kg ha?1 of available N (Nav) produced the maximum fruit yield (FY), enhanced WUE and gave an NM of 85 kg ha?1, while the impact indexes did not exceed the fixed maximum allowable limits and ME was adequate. The proposed indexes proved to be an effective tool for determining the risk of nitrate contamination and confirmed that the optimum dose of N corresponded to the maximum FY with minimal loss of Nl.

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Proper management of the N applied to crops is necessary in order to increase yield, improve water use efficiency (WUE) and reduce the pollutions risks with the least economic, environmental and health costs. A field study with melon crops was conducted during 2005, 2006 and 2007 in central Spain, using 11 different amounts of N. Some environmental indexes have been proposed, to provide an essential tool for determining the groundwater pollution risks associated with common agricultural practices. These indexes are related to variation in the nitrate concentration of drinking water (Impact Index (II)) and groundwater (Environmental Impact Index (EII)). Also, the Management Efficiency (ME) was calculated, which is related to the amount of fruit produced per gram of N leached (Nl). To determine the optimum dose of N, it was also necessary to know the N mineralisation (NM). Our results show that 160 kg ha−1 of available N (Nav) produced the maximum fruit yield (FY), enhanced WUE and gave an NM of 85 kg ha−1, while the impact indexes did not exceed the fixed maximum allowable limits and ME was adequate. The proposed indexes proved to be an effective tool for determining the risk of nitrate contamination and confirmed that the optimum dose of N corresponded to the maximum FY with minimal loss of Nl.

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This paper examines the challenges of water supply in agriculture, with particular emphasis on requirements of field crops, including maize. It places the issue of water supply to agriculture in the context of increasing demands for water from alternatives users, declining quality water, pressure of increasing population, all of which are placing stresses on water availability at local, regional and national levels. The paper also examines existing freshwater resources and the potential impact of climate change on water supply and distribution and consequential impact on water stress incidence in various parts of the globe. It examines competition for water in both industrialized and developing countries, with particular emphasis on the impacts on agriculture and food supplies. The challenge of water use efficiency (WUE) in agriculture is explored with discussion of agronomic, economic and physiological WUE concepts, with specific reference to maize.

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The aim of this study was to determine the collection efficiency of ultrafine particles into an impinger fitted with a fritted nozzle tip as a means to increase contact surface area between the aerosol and the liquid. The influence of liquid sampling volume, frit porosity and the nature of the sampling liquid was explored and it was shown that all impact on the collection efficiency of particles smaller than 220 nm. Obtained values for overall collection efficiency were substantially higher (~30–95%) than have been previously reported, mainly due to the high deposition of particles in the fritted nozzle tip, especially in case of finer porosity frits and smaller particles. Values for the capture efficiency of the solvent alone ranged from 20 to 45%, depending on the type and the volume of solvent. Additionally, our results show that airstream dispersion into bubbles improves particle trapping by the liquid and that there is a difference in collection efficiencies based on the nature and volume of the solvent used.

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The main objective was to compare the environmental impacts of a building undergoing refurbishment both before and after the refurbishment and to assist in the design of the refurbishment with what is learned.

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This paper describes the process adopted in developing an integrated decision support framework for planning of office building refurbishment projects, with specific emphasize on optimising rentable floor space, structural strengthening, residual life and sustainability. Expert opinion on the issues to be considered in a tool is being captured through the DELPHI process, which is currently ongoing. The methodology for development of the integrated tool will be validated through decisions taken during a case study project: refurbishment of CH1 building of Melbourne City Council, which will be followed through to completion by the research team. Current status of the CH1 planning will be presented in the context of the research project.

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This paper will summarise the findings from a study that explored the link between dwelling design, or type, and energy efficiencies in sub-tropical climates. An increasing number of government and private sector development companies are initiating projects that aim to deliver enhanced environmental outcomes at both sub-divisional and dwelling levels. The study used AccuRate, a new thermal modelling tool developed by CSIRO that responds to the need to improve ventilation modelling. The study found that dwellings developed in conjunction with the Departments of Housing and Public Works have set the benchmark. It provides a snapshot of the energy efficiency of a range of dwelling types found in recent subdivisions. However, the trend toward increasing urban densities may reduce the likelihood that cooling breezes will be available to cool dwellings. The findings are relevant to regulators, designers and industry in all states interested in reducing the energy used to cool dwellings in summer.

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The ability to assess a commercial building for its impact on the environment at the earliest stage of design is a goal which is achievable by integrating several approaches into a single procedure directly from the 3D CAD representation. Such an approach enables building design professionals to make informed decisions on the environmental impact of building and its alternatives during the design development stage instead of at the post-design stage where options become limited. The indicators of interest are those which relate to consumption of resources and energy, contributions to pollution of air, water and soil, and impacts on the health and wellbeing of people in the built environment as a result of constructing and operating buildings. 3D object-oriented CAD files contain a wealth of building information which can be interrogated for details required for analysis of the performance of a design. The quantities of all components in the building can be automatically obtained from the 3D CAD objects and their constituent materials identified to calculate a complete list of the amounts of all building products such as concrete, steel, timber, plastic etc. When this information is combined with a life cycle inventory database, key internationally recognised environmental indicators can be estimated. Such a fully integrated tool known as LCADesign has been created for automated ecoefficiency assessment of commercial buildings direct from 3D CAD. This paper outlines the key features of LCADesign and its application to environmental assessment of commercial buildings.

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Buildings consume resources and energy, contribute to pollution of our air, water and soil, impact the health and well-being of populations and constitute an important part of the built environment in which we live. The ability to assess their design with a view to reducing that impact automatically from their 3D CAD representations enables building design professionals to make informed decisions on the environmental impact of building structures. Contemporary 3D object-oriented CAD files contain a wealth of building information. LCADesign has been designed as a fully integrated approach for automated eco-efficiency assessment of commercial buildings direct from 3D CAD. LCADesign accesses the 3D CAD detail through Industry Foundation Classes (IFCs) - the international standard file format for defining architectural and constructional CAD graphic data as 3D real-world objects - to permit construction professionals to interrogate these intelligent drawing objects for analysis of the performance of a design. The automated take-off provides quantities of all building components whose specific production processes, logistics and raw material inputs, where necessary, are identified to calculate a complete list of quantities for all products such as concrete, steel, timber, plastic etc and combines this information with the life cycle inventory database, to estimate key internationally recognised environmental indicators such as CML, EPS and Eco-indicator 99. This paper outlines the key modules of LCADesign and their role in delivering an automated eco-efficiency assessment for commercial buildings.

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Energy efficient lubricants are becoming increasingly popular. This is due to a global increase in environmental awareness combined with the potential of reducing operating costs. A new test method of evaluating the energy efficiency of gear oils has been described in this report. The method involves measuring the power required by an FZG test rig to run while using a particular test lubricant. For each oil that was being evaluated, the rig was run for 10 minutes at a load stage of 10. Six extreme pressure (EP) industrial gear oils of mineral base were tested. The difference in power requirements between the best and the worst performing oils was 2.77 and 3.24 kW, respectively. This equates to a 14.6% reduction in power, a significant amount if considered in relation to a high powered industrial machine. The oils of superior performance were noticed to run at reduced temperatures. They were also more expensive than the other products of lesser performance.

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It has long been recognised that government and public sector services suffer an innovation deficit compared to private or market-based services. This paper argues that this can be explained as an unintended consequence of the concerted public sector drive toward the elimination of waste through efficiency, accountability and transparency. Yet in an evolving economy this can be a false efficiency, as it also eliminates the 'good waste' that is a necessary cost of experimentation. This results in a systematic trade0off in the public sector between the static efficiency of minimizing the misuse of public resources and the dynamic efficiency of experimentation. this is inherently biased against risk and uncertainty and therein, explains why governments find service innovation so difficult. In the drive to eliminate static inefficiencies, many political systems have susequently overshot and stifled policy innovation. I propose the 'Red Queen' solution of adaptive economic policy.

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This paper presents the possibility of utilizing a current source topology instead of a voltage source as an efficient, flexible and reliable power supply for plasma applications. A buck-boost converter with a current controller has been used to transfer energy from an inductor to a plasma system. A control strategy has also been designed to satisfy all the desired purposes. The main concept behind this topology is to provide high dv/dt regardless of the switching speed of a power switch and to control the current level to properly transfer adequate energy to various plasma applications.