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排序方式: 共有613条查询结果,搜索用时 15 毫秒
1.
Management practices for irrigation schemes can often be improved by modelling the behaviour of a scheme and by evaluating its efficiency statistics. However, looking at an irrigation scheme without regard for other water uses within the river basin may not be effective. Efficiencies computed in this way are local and, since water may be used many times within the same basin, may not be realistic. Changes in water uses (e.g. irrigation, industrial, power production, urban water supply, navigation, environmental, recreational) will often have effects on other uses; and changes in irrigation schemes (management,structural, crop pattern) may affect other users within the basin. In addition, all water users will be affected by external changes such as changes in land cover or in climate. As demand for water increases, these links become more important until, at some stage, there is insufficient water for all users and hard choices must be made. Hydrological modelling is a tool that can be used to relate irrigation schemes to the other water uses within a river basin and can help in assessing real productivities and in evaluating alternative patterns of water usage. This paper discusses the techniques available to simulate irrigation schemes within overall basin water resources using, as an example, an intensively utilized basin in western Turkey. 相似文献
2.
Xavier Pelet Daniel Favrat Geoff Leyland 《International Journal of Thermal Sciences》2005,44(12):1180
The methods for designing, planning and managing integrated energy systems, while holistically considering the major economic and environmental factors, are still embryonic. However, the first phase of the design is often crucial if we want to manage resources better and reduce energy consumption and pollution. Considering integrated energy systems implies dealing with complex systems in which the synergy between the various components is best exploited (for example the thermal energy of a diesel engine produced during the night is complimented by the Rankine organic cycle of a solar thermal plant). The context of isolated communities further increases the difficulties when considering the long distance of transport required to supply fossil fuels. These sites are often located in very precarious environments, with limited or nonexistent resources except for solar energy, and with frequent additional needs for desalination (in arid zones).This paper illustrates a holistic method to rationalize the design of energy integrated systems. It is based on a superstructure (collection of models of all envisaged technologies) and a multi-objective optimisation (resources, demand, energy, emission, costs) using an evolutionary algorithm. The approach proposed allows the identification of more complete and more coherent integrated configurations characterizing the most promising designs (also taking into account the time dependency aspects). It also allows to better structure the information in view of a participative decision approach. The study shows that the economic implementation of renewable energy (solar) is even more difficult, compared to diesel based solutions, in cases of isolated communities with high load variations. New infrastructure or retrofit cases are considered. 相似文献
3.
Kawsar P. Salam Geoff J. Thomas Ciara Beard Robert Loughman William J. MacLeod Moin U. Salam 《Food Security》2013,5(3):319-325
This work was done to demonstrate the opportunities provided by application of meta-analysis in plant pathology. It was a case study used to determine the effectiveness of foliar fungicides in minimising yield loss from a complex of yellow spot (Pyrenophora tritici-repentis) and septoria nodorum blotch (Stagonospora nodorum, teleomorph: Phaeosphaeria nodorum) (YS-SNB disease complex) on wheat in the northern grain-belt of Western Australia. Forty-seven datasets of experimental results from 14 growing seasons, using 18 varieties sprayed one to three times, predominantly with tebuconazole or propiconazole fungicides, were analysed. Across the datasets, the wheat yield gain from fungicide application was 297 kg ha?1 with a 95 % confidence interval of 11.6 kg ha?1. Significant yield gains resulted from single or multiple applications of fungicides. Both propiconazole and tebuconazole, increased yield of wheat affected by the YS–SNB disease complex, with yield gain from propiconazole being greater than that from tebuconazole. Yield response varied significantly among crop growing seasons. Meta-analysis was able to aggregate a large number of experimental results and answer important questions related to the variables that influenced those results; in this case the effectiveness of fungicides in minimising yield loss from the YS-SNB disease complex on wheat. It also identified areas where further research needs to be done. It is concluded that meta-analysis has the potential to contribute to similar analyses in other crop disease systems. 相似文献
4.
Andreas Kiermeier Mark Tamplin Damian May Geoff Holds Michelle Williams Alison Dann 《Food microbiology》2013
Packaging fresh lamb in a vacuum (VAC) versus a 100% CO2 modified atmosphere (MAP) may influence product shelf-life and the bacterial communities. While VAC is a common packing method and 100% CO2 MAP is used in some countries, there is little information about how these different techniques affect the growth of spoilage bacteria and sensory attributes of lamb. The aim of this study was to assess changes in microbiological and organoleptic properties, and determine differences in microbial communities by terminal restriction fragment length polymorphism (TRFLP) and 454 pyrosequencing, in bone-in (BI) and bone-out (BO) MAP- and VAC-packed lamb shoulders stored at −0.3 °C over 12 wk. VAC and MAP lamb shoulders were acceptable in sensory test scores over 12 wk of storage at −0.3 °C, despite total viable count (TVC) and lactic acid bacteria (LAB) levels increasing to 8 log10 CFU/cm2 for VAC lamb and 4–6 log10 CFU/cm2 for MAP lamb. Similar to the sensory results, there were no significant differences in microbial communities between BI and BO product. However, types of bacteria were different between VAC and MAP packaging. Specifically, while VAC shoulder became dominated by Carnobacterium spp. in the middle of the storage period, the MAP shoulder microbial population remained similar from the start until later storage times. 相似文献
5.
Geoff Fisher 《纺织导报》2002,(1):49-50
意大利织机制造商Promatech公司以Somet品牌推出了一种新型剑杆织机。这种以“Alpha”命名的织机于2001年9月底首次在一个演示间里亮相,随后又成为新加坡ITMA Asia展会上的一个亮点。Somet公司剑杆织机产品经理Piermarco Arnoldi先生说,这种新型织机操作简便,可靠性高和多用性强,能以非常高的织造速度织许多种织物。一、Alpha剑杆织机的性能1.操作简便Alpha的设计使操作工很容易接近机器和修复断头。例如:打纬点与胸梁之间的距离大幅度缩短,使操作工更容易用手来… 相似文献
6.
Aaron Gosling Geoff W. Stevens Andrew R. Barber Sandra E. Kentish Sally L. Gras 《Food chemistry》2010
The production of prebiotic galactooligosaccharides (GOS) by the β-galactosidase catalysed conversion of lactose has become commercially important. Yet it remains a challenge to sufficiently understand the structure and activity of β-galactosidase, to increase the efficiency of transgalactosylation and GOS production and to improve the quality of GOS products in a rational way. This review covers the broad but related aspects of GOS synthesis including: the structure and reaction mechanism of β-galactosidase, factors effecting yield and productivity of GOS synthesis systems, the structure of GOS products, models for the kinetics of GOS synthesis and reactor configurations for GOS synthesis. It aims to couple recent discoveries with established knowledge to enhance understanding of the complex biochemistry of GOS synthesis. 相似文献
7.
Relationship between collagen characteristics,lipid content and raw and cooked texture of meat from young bulls of fifteen European breeds 总被引:1,自引:0,他引:1
Mette Christensen Per Ertbjerg Sebastiana Failla Carlos Sañudo R. Ian Richardson Geoff R. Nute José L. Olleta Begoña Panea Pere Albertí Manuel Juárez Jean-François Hocquette John L. Williams 《Meat science》2011
Variations in texture were determined for 10 day aged raw and cooked Longissimus thoracis (LT) muscle from 436 bulls of 15 European cattle breeds slaughtered at an age of 13–16 months. Variations in texture were related to differences in pH 24 h post-mortem, sarcomere length, collagen characteristics and lipid content. The shear force of cooked meat samples varied from 43.8 to 67.4 N/cm2. Simmental, Highland and Marchigiana cattle had the highest shear force values and Avileña-Negra Ibérica, Charolais, Casina and Pirenaica cattle had the lowest values. Cooked meat toughness showed a weak negative correlation to lipid content (P < 0.001) but no correlation to collagen characteristics. Raw meat texture measured by compression correlated positively (P < 0.001) with total and insoluble collagen. In conclusion, collagen characteristics showed correlation to raw meat texture but not to cooked meat toughness of LT muscle in European young bulls. 相似文献
8.
Karl Fraser Scott J. Harrison Geoff A. Lane Don E. Otter Yacine Hemar Siew-Young Quek Susanne Rasmussen 《Food chemistry》2012
Tea is the second most consumed beverage in the world and its consumption has been associated with numerous potential health benefits. Factors such as fermentation methods, geographical origin and season can affect the primary and secondary metabolite composition of tea. In this study, a hydrophilic interaction liquid chromatography (HILIC) method coupled to high resolution mass spectrometry in both positive and negative ionisation modes was developed and optimised. The method when combined with principal component analysis to analyse three different types of tea, successfully distinguished samples into different categories, and provided evidence of the metabolites which differed between them. The accurate mass and high resolution attributes of the mass spectrometric data were utilised and relative quantification data were extracted post-data acquisition on 18 amino acids, showing significant differences in amino acid concentrations between tea types and countries. This study highlights the potential of HILIC chromatography combined with non-targeted mass spectrometric methods to provide a comprehensive understanding of polar metabolites in plant extracts. 相似文献
9.
To assess the suitability of transmission electron microscopy (TEM) for investigating the detailed process of coal/solvent interaction, TEM observations have been made of small blocks of Liddell vitrinite that had been treated with tetralin in an autoclave at 320 and 350 °C. In vitrinite treated at 320 °C cell cavity fillings became porous, while the walls between cell cavities remained uniform and showed no internal texture. In vitrinite particles treated with tetralin at 350 °C two zones were recognizable at the edges of the particles: a more electron-dense inner zone and a less electron-dense outer zone. Also present in these specimens were plastospheres consisting of two different materials, primary vitroplast (a more electron-dense core) and secondary vitroplast (a less electron-dense crust). Such detailed texture has not been observed with incident light microscopy, and TEM techniques provide useful information not previously obtainable. 相似文献
10.
Vogel R Willmott G Kozak D Roberts GS Anderson W Groenewegen L Glossop B Barnett A Turner A Trau M 《Analytical chemistry》2011,83(9):3499-3506
The use of a "size-tunable" polyurethane resistive pulse sensor for quantitative sizing of nano- and microparticles is presented. A linear relationship, as first suggested by Maxwell, between particle volume and change in electric resistance across the pore was observed. Particle sizes were quantified for a given size-tunable membrane, by first creating a linear calibration curve to a series of monodisperse carboxylated polystyrene particles of various diameters and then applying this curve to calculate the size of "unknown" nanoparticles. The diameters of a selection of synthetic and biological particles, being PMMA and nonfunctionalized polystyrene particles, along with biological nanoparticles (adenovirus) were calculated using this methodology. Calculated particle diameters and coefficients of variation were shown to be in good agreement with both transmission electron microscopy and dynamic light scattering results. 相似文献