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排序方式: 共有418条查询结果,搜索用时 15 毫秒
101.
Economic Value of Tree Fruit Production in Jordan Valley from a Virtual Water Perspective 总被引:1,自引:0,他引:1
Khaldoon Abdalah Mourad Hartmut Gaese Amer S. Jabarin 《Water Resources Management》2010,24(10):2021-2034
The continuous high demand of water resources for agricultural uses in Jordan is leading to a water crisis. A possible partial solution may be to import food which requires large amounts of water to grow instead of cultivating high water consuming crops. Crops such as banana and citrus cause a huge virtual water loss, which can be reduced by cultivating other less water-demanding crops. This paper focuses on analyzing the economic value of cultivating tree fruit from a virtual water perspective. The virtual water calculations in this study depend on the average rainfall, water quota, and the crops’ water requirements (CWR). The gross profit to the water use ratio showed that banana has the lowest value 0.085 JD/m3, while lemon has the highest value 1.65 JD/m3. The calculations show that the average embedded water in fruits varies from about 470 m3/ton for grapes to about 2,500 m3/ton for dates. Banana and citrus plantations consume about 21 and 71 million cubic meters (MCM) annually, respectively, which represent about 85% of the total water consumption in fruit tree plantation. The virtual water flow estimation embedded in fruits shows that Jordan imports about 77 MCM per year. However it exports about 29 MCM per year. The results were analyzed from an integrated water resources management (IWRM) perspective. The analysis shows that a way to recover some of the water costs involved in, e.g., banana production would be to increase the fertilizer cost by about 10%. This would double the water cost and increase the banana production cost by about 6.8%. Using this alternative could be a way to better manage the huge losses in virtual water involved in banana production in the Jordan Valley. 相似文献
102.
Mourad MC Wijnhoven JE Van't Zand DD van der Beek D Lekkerkerker HN 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2006,364(1847):2807-2816
Gelation is a common effect in aqueous suspensions of charged colloidal clay platelets at concentrations as low as 1 wt%. However, in systems of charged gibbsite [Al(OH)3] platelets, gelation can be delayed to concentrations as high as 50 wt% depending on the ionic strength. We investigated the phase behaviour of this system approaching the state of gelation in the delicate region between attractive and repulsive states that originate from competition between Coulomb repulsion and van der Waals attraction. As a function of the ionic strength, isotropic-nematic, nematic-columnar and isotropic-columnar phase separations were observed. Moreover, compression by gravitational forces allowed us to observe phase separation that is arrested by gelation in the homogeneous suspensions. 相似文献
103.
Assessing the economic value of renewable distributed generation in the Northeastern American market
Mourad Ben Amor Pierre-Olivier Pineau Caroline Gaudreault Réjean Samson 《Renewable & Sustainable Energy Reviews》2012,16(8):5687-5695
Incentive programs and tax rebates are commonly offered to offset the high initial costs of small-scale renewable energy systems (RES) and foster their implementation. However, the economic costs of RES grid integration must be fully known in order to determine whether such subsidies are justified. The objective of this paper is to assess the economic value of RES, including their environmental benefits, using hourly generation information in conjunction with hourly wholesale price data. Reaching the paper′s objective will provide a better estimate of the bias that could result from neglecting 1) the time pattern of the hourly wholesale price, 2) the impacts of carbon taxes on the hourly wholesale price and 3) the value of the marginal hourly GHG emissions. Selected RES include two types of grid-connected photovoltaic panels (3 kWp mono- and poly-crystalline) and three types of micro-wind turbines (1, 10 and 30 kW) modeled for different climatic conditions in the province of Quebec (Canada). The cost of electricity is based on the technical performance of these RES using a life cycle costing methodology. The economic value of RES electricity is estimated using the hourly wholesale electricity price in Northeastern American markets in 2006–2008. Results show that distributed generation (DG) has no economic benefits using the selected RES, even with a US$100/tonne of CO2-equivalent carbon tax. This finding remains the same when the value of the avoided GHG emissions is fully internalized, except for one scenario (micro-wind 30 kW). Our results are key to understanding the extent to which subsidies for distributed RES can be economically sustainable when the latter are integrated into regional networks driven by centralized electricity production. 相似文献
104.
Egan T. Mourad S. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2005,13(8):984-988
This paper introduces a new approach to testing a basic analog-only delay-locked loop (DLL) that is embedded in a field-programmable gate array, an application specific integrated circuit, or a system-on-chip (SoC). Part of the DLL circuitry is duplicated and then connected to the DLL in a way that produces a replica of the control voltage. This shadow of the control voltage is used to measure the loop's response to a step in phase. The concept of test construct (TC) gain is introduced as a means of improving detectability. The benefit of the testing approach is demonstrated by injecting defects into the DLL and detecting them through the TC at the observation point. 相似文献
105.
Litvin M.E. Mourad S. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2005,13(4):462-475
A new family of self-reset logic (SRL) cells is presented in this paper. The single-ended basic structure proposed realizes an incomplete logic family, since it is incapable of inverting logic. Thus, a dual-rail SRL (DRSRL) implementation is also proposed. These cells maintain small delay variations for all input combinations, once minimum timing requirements on inputs are satisfied, and produce output pulses of fairly constant width for varying fanout, leaving enough headroom in the design to accommodate process, supply voltage, and temperature variations. These properties simplify the implementation of data-path and control circuits where the logic depth does not affect the stage output pulse width, eliminating the need for pulse-width controlling circuits required in previous works on SRL. In SRL, power is consumed only if new data are pumped through the logic. The clock grid is limited to the registers that launch and receive the signal path. The clocking overhead is thus reduced, compared with other dynamic designs, and it is especially suitable for wave pipelining. Case study examples and simulated characterization data are included to show the design methodology. 相似文献
106.
Renaud Metz Jonathan Morel Mourad Houabes Julien Pansiot Merdad Hassanzadeh 《Journal of Materials Science》2007,42(24):10284-10287
High current characterization of SnO2-based varistors have been carried out and the results obtained have been compared with those ZnO-based commercial surge arresters.
It is shown that for a high temperature sintering (1350 °C), the leakage current, breakdown voltage and the saturation at
high current density are similar between both types of surge arresters. The paper shows, for the first time, that the high
breakdown voltage observed with tin dioxide cannot be easily maintained since the saturation of the ceramics is reached for
current densities of several amperes per square centimetre. 相似文献
107.
Marina Dabić Nebojša Stojčić Komivi Afawubo Mourad Chouki Nicolas Huck 《Creativity & Innovation Management》2023,32(3):425-441
Design is commonly understood as a key element of products, contributing to their distinctiveness, usability and aesthetics. The success of a product is increasingly related to the user experience or the aesthetics of the user interface, meaning that design is increasingly important in the digital environment. The shift in competitive focus to the customer induced by digital design encourages companies to innovate and can also lead to changes in internal operations, market orientation and the reconfiguration of external collaboration procedures. This dimension of digital design-induced effects has to date seen very little research. The objective of this study is to investigate how digital design-induced changes in market orientation, internal restructuring and external cooperation affect firms' competitive orientation. The simultaneous equation framework was applied to a survey of 515 user interface and experience designers from France. Our results suggest that market orientation is not the only channel through which digital design influences firm competitiveness. Digital design leads to organizational change and the reconfiguration of external relationships that directly and indirectly help companies build competitive advantages and increase customer satisfaction. 相似文献
108.
109.
Loukil Faiza Boukadi Khouloud Abed Mourad Ghedira-Guegan Chirine 《World Wide Web》2021,24(5):1645-1663
World Wide Web - Blockchain technology enables several untrustworthy parties to execute inter-organizational business processes in a tamper-proof manner. Existing approaches are based on smart... 相似文献
110.
Ahmed Dallil Abdelaziz Ouldali Mourad Oussalah 《Journal of Intelligent and Robotic Systems》2012,67(3-4):219-227
In this paper, we present a new method for data association in multi-target tracking. The representation and the fusion of the information in our method are based on the use of belief function. The proposal generates the basic belief mass assignment using a modified Mahalanobis distance. While the decision making process is based on the extension of the frame of hypotheses. Our method has been tested for a nearly constant velocity target and compared with both the nearest neighbor filter and the joint probabilistic data associations filter in highly ambiguous cases. The results demonstrate the feasibility of the proposal and show improved performance compared to the aforementioned alternative commonly used methods. 相似文献