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131.
Intizar Hussain Muhammad Mudasser Munir A. Hanjra Upali Amrasinghe David Molden 《国际水》2013,38(2):189-200
Abstract Increasing water scarcity, degradation of land and water resources, continuing low agricultural productivity, and increasing populations are posing the largest ever challenges for development of agricultural economies in many developing countries including Pakistan. Using panel data from irrigated settings in Chaj sub-basin of the Indus basin in Pakistani Punjab, we attempt to: (a) analyze the causes of low productivity; (b) disentangle factors (both land, water and other factors) contributing to productivity variations; and (c) identify limits and opportunities for narrowing productivity gaps and increasing overall wheat production, with a view to enhance food security for the poor. The results of the study indicate that locational inequities in distribution of canal water, use of groundwater of varying quality, differences in use of seed varieties, and other inputs lead to significant variations in wheat productivity. Key implications are that large gains in wheat productivity are possible by (a) improving the production environment at the tail-end through integrated water management practices; (b) adjusting the mix of canal and groundwater use; and (c) using technological interventions to improve the adoption of modern wheat varieties and dissemination of knowledge on planting dates and timings and application rates of inputs, especially water and fertilizer. Not only such interventions are economically, financially, and environmentally desirable, they are also pro-poor. What is needed is a strong political will and commitment. 相似文献
132.
A. Mohammed Hussain Jens V.T. HøghTorben Jacobsen Nikolaos Bonanos 《International Journal of Hydrogen Energy》2012
This report concentrates on high performance anodes appropriate for SOFCs operating at low temperatures (400–600 °C). Symmetrical cells were made by screen printing of Nb-doped SrTiO3 (STN) on both sides of a dense ScYSZ electrolyte. Backbones I (36% porosity) and II (47% porosity) were obtained by sintering STN in air and reducing atmosphere, respectively. The porous microstructures were then infiltrated with Ni and Gd-doped CeO2 (CGO) precursors to incorporate the electrocatalytically active sites. The electrochemical performance of the anode was improved with the increment of Ni-CGO loadings. The gas diffusion impedance was investigated with He and N2 in H2/H2O gas mixtures and by varying the H2O content at 655 °C. This study indicated that the gas diffusion in these electrodes are influenced by Knudsen and bulk diffusion. 相似文献
133.
One of the main reasons behind the appearance of early distresses in Jordan roads and the low surface skid resistance is the use of marginal quality limestone aggregate. Large quantities of good quality basalt are available in the Northeastern parts of Jordan. In this research, the possibility of improving the properties of local asphalt concrete mixes by replacing different portions of the normally used limestone aggregate by basalt was investigated. The replacement included total replacement of the limestone by basalt, replacing the coarse aggregate, and replacing the fine aggregate. Results showed that the optimal mix was the mix that had basalt coarse aggregate and limestone fine aggregate. In order to overcome the stripping potential of the optimal mix, 20% of the filler portion of the aggregate, material smaller than 0.075 mm, was replaced by lime. The optimal mix showed superiority, over the tested mixes, in all the evaluated properties, which were Marshall Stability, indirect tensile strength, stripping resistance, resilient modulus, dynamic creep, fatigue, and rutting. 相似文献
134.
The laminar helical flow of non-Newtonian pseudoplastic fluids in concentric and eccentric annuli with a rotating inner cylinder has been investigated numerically. A finite volume algorithm with a nonstaggered grid system is used to analyze the problem. A nonorthogonal curvilinear coordinate system is employed to handle the irregular geometry of aneccentric annulus. The power-law constitutive equation is used to model the shear rate dependent viscosity of a pseudoplastic fluid. The computer code is validated against an available analytical solution for helical flow in a concentric annulus. It is observed that for a certain axial pressure gradient the axial flow rate increases within creasing rotational speed of the inner cylinder. The torque needed to rotate the inner cylinder decreases with increasing axial pressure gradient. These are explained in terms of the shear-thinning effect of a pseudoplastic fluid. The discharge as well as torque are found to increase with increasing eccentricity. The flow field in an eccentric annulus is complex in nature since vigorous secondary flow is produced in addition to the primary axial helical flow. The location and extent of the secondary flow is studied and theresults are presented for various eccentricities. The results will be useful in planning oil and gas well drilling operations. 相似文献
135.
In the 21st century, all the major countries around the world are coming together to reduce the impact of energy generation and consumption on the global environment. Energy conservation and its efficient usage has become a top agenda on the desks of many governments. In the last decade, the drive to make homes automated and to deliver a better assisted living picked pace and the research into home automation systems accelerated, usually based on a centralized residential gateway. However most devised solutions fail to provide users with information about power consumption of different house appliances. The ability to collect power consumption information can lead us to have a more energy efficient society. The goal addressed in this paper is to enable residential gateways to provide the energy consumption information, in a machine understandable format, to support third party applications and services. To reach this goal, we propose a Semantic Energy Information Publishing Framework. The proposed framework publishes, for different appliances in the house, their power consumption information and other properties, in a machine understandable format. Appliance properties are exposed according to the existing semantic modeling supported by residential gateways, while instantaneous power consumption is modeled through a new modular Energy Profile ontology. 相似文献
136.
Hussain A. Al-Saadi Ali A. Al-Lami Falih A. Hassan Amer A. Al-Dulymi 《The International journal of environmental studies》2013,70(5):589-598
Seasonal samples were taken from four selected stations on the Habbaniya lake, middle of Iraq during 1997, to study six heavy metals (Cu, Cd, Pb, Ni, Mn, and Zn), in water suspended particles, sediments and aquatic plants. Five plant species were collected, represented the most dominant in the lake, namely Myriophyllum verticillatum, Potamogeton crispus, P. pectinatus, Ceratophyllum demersum and Vallisnaria spiralis . Zn had the highest concentration among the studied metals in filtered water and suspended particles with an average of 4.08 w g/l and 26088 w g/g, respectively. Whereas, Mn had the highest in the sediments and all studied aquatic plants, which ranged between 213.3- 2027 w g/g and 100-1725 w g/g, respectively, Meanwhile, Cd had the lowest concentration in all studied samples. 相似文献
137.
Steel slag, which is produced locally in great amounts, has a negative impact on the environment when disposed. Local steel slag has a low CaO content and has no pozzolanic activity.In this research, local unprocessed steel slag is introduced in concrete mixes. Various mixes with compressive strength ranging from 25 to 45 MPa are studied. The slag is used as fine aggregate replacing the sand in the mixes, partly or totally. Ratios of 0%, 15%, 30%, 50% and 100% are used.Depending on the grade of concrete, the compressive strength is improved when steel slag is used for low sand replacement ratios (up to 30%).When optimum values are used, the 28-day tensile strength of concrete is improved by 1.4–2.4 times and the compressive strength is improved by 1.1–1.3 times depending on the replacement ratio and the grade of concrete. The best results are obtained for replacement ratios of 30–50% for tensile strength and 15–30% for compressive strength.Therefore, the use of steel slag in concrete would enhance the strength of concrete, especially tensile strength, provided the correct ratio is used. 相似文献
138.
Salleh Emee Marina Zuhailawati Hussain Ramakrishnan Sivakumar Dhindaw Brij Kumar 《Metallurgical and Materials Transactions A》2017,48(5):2519-2528
Metallurgical and Materials Transactions A - Magnesium (Mg) and its alloys have shown potential for use in the biomedical industry due to their excellent biological performance and biodegradability... 相似文献
139.
Ahmad Farid Abidin Azah Mohamed Hussain Shareef 《Expert systems with applications》2011,38(12):14969-14975
The conventional power swing schemes used in distance relay operation are not fast enough to detect and distinguish a fault, stable swing and unstable swing and this may lead to unintended tripping of protection devices. Therefore, there is a need for fast detection of unstable swings so as to improve the reliability of distance relay operation. This paper presents an intelligent approach for detecting unstable swings during distance relay operation using the S-transform signal processing technique and artificial neural networks. To illustrate the effectiveness of the proposed approach, simulations were carried out on the IEEE 39 bus test system using the PSS/E software. Test results showed that the proposed approach using S-transform, multi layer perceptron network and probabilistic neural network can accurately detect and classify fault, stable swing, unstable swing, fault clearance and post fault events for correct distance relay operation. 相似文献
140.
Multifunctional or structural electrolytes are characterized by ionic conductivity high enough to be used in the electrochemical devices and mechanical performance suitable for the structural applications. Preliminary insights are provided into the combustion behavior of structural bi-continuous electrolytes based on bisphenol A diglycidyl ether (DGEBA), synthesized using the techniques of reaction induced phase separation and emulsion templating. The effect of the composition of the structural electrolytes and external heat flux on the behavior of the formulations were studied using a cone calorimeter with gases formed during testing analyzed using FTIR. The composition of the formulations investigated was changed by varying the type and amount of the ion conductive part of the bi-continuous electrolyte. Two ionic liquids, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-TFSI) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4), as well as a deep eutectic solvent (DES) based on ethylene glycol and choline chloride, were used. The results obtained confirm that time to ignition, heat release rate (HRR), total mass loss, as well as the composition of the gases released during tests depend on the composition of the formulations. Addition of liquid electrolyte is found to reduce the time to ignition by up to 10% and the burning time by between 28% and 60% with the added benefit of reducing the HRR by at least 34%. Gaseous products such as CO2, CO, H2O, CH4, C2H2, N2O, NO, and HCN were detected for all formulations with the gases SO2, NH3, HCl, C2H4, and NH3 found to be for certain formulations only. 相似文献