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101.
The characteristics of dust in a plasma sheath are investigated in the presence of an external magnetic field and taking into account the dust-neutral collision force. The continuity and momentum equations of ions and dust particles are solved numerically with various magnitudes of collision force by using the fluid model. The numerical results have revealed that the collision force reduces the dust gyro radius, changes the positions of the extrema of the dust density and the velocity in the depth direction. It is shown that the collision force reduces the dust kinetic energy which has no fluctuation even in a strong external magnetic field. 相似文献
102.
Saqib Murtaza Farhad Ali Nadeem Ahmad Sheikh Ilyas Khan Kottakkaran Sooppy Nisar 《计算机、材料和连续体(英文)》2021,67(3):2915-2932
The present article aims to examine the heat and mass distribution in a free convection flow of electrically conducted, generalized Jeffrey nanofluid in a heated rotatory system. The flow analysis is considered in the presence of thermal radiation and the transverse magnetic field of strength B0. The medium is porous accepting generalized Darcy’s law. The motion of the fluid is due to the cosine oscillations of the plate. Nanofluid has been formed by the uniform dispersing of the Silver nanoparticles in regular engine oil. The problem has been modeled in the form of classical partial differential equations and then generalized by replacing time derivative with Atangana–Baleanu (AB) time-fractional derivative. Upon taking the Laplace transform technique (LTT) and using physical boundary conditions, exact expressions have been obtained for momentum, energy, and concentration distributions. The impact of a number of parameters on fluid flow is shown graphically. The numerical tables have been computed for variation in the rate of heat and mass transfer with respect to rooted parameters. Finally, the classical solution is recovered by taking the fractional parameter approaching unity. It is worth noting that by adding silver nanoparticles in regular engine oil, its heat transfer rate increased by 14.59%, which will improve the life and workability of the engine. 相似文献
103.
Collaborative planning, forecasting and replenishment (CPFR) as an interconnection scheme between organisations have been shown to have significant benefits. Since its inception in the 1990s, its uptake has been lower than originally predicted. This paper identifies the major barriers and their interrelationships in CPFR implementations with a focus on high-tech industries. Interpretive Structural Modelling is used with a group of CPFR experts from industry/academia and Matrice d’Impacts Croisés Multiplication Appliquée àun Classement analysis to identify the driving and dependence powers. The paper identified 45 CPFR barriers and classifies them into four categories based on expert opinion, with only 13 of these determined to be significant. The results indicate that in terms of categories, managerial barriers are a significant root cause for both process and cultural barriers and CPFR implementation difficulties. It also indicates that although the importance of information technology to launch collaborative schemes has been addressed by many scholars, technology alone is not the complete solution for successful CPFR implementation. The paper has significant practical implications for organisations as it identifies the main CPFR barriers and their causal relationships. This will help firms in the process of CPFR strategy development particularly for mitigation strategies for dominant barriers. 相似文献
104.
Saqib Murtaza Farhad Ali Aamina Nadeem Ahmad Sheikh Ilyas Khan Kottakkaran Sooppy Nisar 《计算机、材料和连续体(英文)》2020,65(3):2033-2047
It is a very difficult task for the researchers to find the exact solutions to
mathematical problems that contain non-linear terms in the equation. Therefore, this article
aims to investigate the viscous dissipation (VD) effect on the fractional model of Jeffrey
fluid over a heated vertical flat plate that suddenly moves in its own plane. Based on the
Atangana-Baleanu operator, the fractional model is developed from the fractional
constitutive equations. VD is responsible for the non-linear behavior in the problem. Upon
taking the Laplace and Fourier sine transforms, exact expressions have been obtained for
momentum and energy equations. The influence of relative parameters on fluid flow and
temperature distribution is shown graphically. As special cases, and for the sake of
correctness, the corresponding results for second-grade fluid and Newtonian viscous fluid
are also obtained. It is interesting to note that fractional parameter α provides more than
one line as compared to the classical model. This effect represents the memory effect in the
fluid which is not possible to elaborate by the classical model. It is also worth noting that
the temperature profile of the generalized Jeffrey fluid rises for higher values of Eckert
number which is due to the enthalpy difference of the boundary layer. 相似文献
105.
106.
As the development of extreme-ultraviolet (EUV) lithography progresses, interest grows in the extension of traditional optical components to the EUV regime. The strong absorption of EUV by most materials and its extremely short wavelength, however, make it very difficult to implement many components that are commonplace in the longer wavelength regimes. One such component is the diffractive optical element used, for example, in illumination systems to efficiently generate modified pupil fills. The fabrication and characterization of an EUV binary phase-only computer-generated hologram is demonstrated, allowing arbitrary far-field diffraction patterns to be generated. Based on reflective architecture, the fabricated device is extremely efficient. Based on an identically fabricated null hologram, the absolute efficiency into one diffracted order of 22% has been demonstrated. In the case where axially symmetric diffraction patterns are desired (both positive and negative diffraction orders can be used), the efficiency can be twice as high. 相似文献
107.
Farhad Heidary Ali Nemati Kharat Alireza Khodabakhshi Sayed Siavash Madaeni 《Bulletin of Materials Science》2017,40(4):631-644
Homogeneous cation-exchange membranes were prepared through evaporation and phase inversion methods using sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) and sulfonated polyvinylchloride as binders. The effect of polymers blend’s ratio and preparation method on structure and electrochemical properties of the prepared membranes were evaluated. The microstructures of the membranes were investigated by scanning electron microscopy (SEM) and the sulfonation of polyvinylchloride was confirmed by elemental analyses. Moreover, the membranes performance was evaluated by ion-exchange capacity (IEC), fixed ion concentration, membrane potential, transport number, permselectivity, areal resistance, ionic permeability, flux of ions, current efficiency, membrane oxidative stability, mechanical properties and water content tests. The results indicated that IEC and water content were affected by the SPPO content and microstructures of the membranes. The results showed increased efficiency and suitable electrochemical properties for membranes prepared by the evaporation method in comparison with others. Also, \(\hbox {Fe}_{2}\hbox {O}_{3}\) nanoparticles were synthesized at room temperature by a simple sonochemical reaction between ferric chloride and NaOH. The results revealed that the addition of different amounts of \(\hbox {Fe}_{2}\hbox {O}_{3}\) nanoparticles to the polymeric matrix could affect the hydrophilicity and transport properties of ion-exchange membranes. 相似文献
108.
109.
Farhad?M.?HossainEmail author M.?HasanuzzamanEmail author N.?A.?Rahim H.?W.?Ping 《Clean Technologies and Environmental Policy》2015,17(4):859-871
Malaysia is rich in renewable energy (RE) resources. Hybrid systems of these resources can contribute strongly to the electrification and sustainable development of rural areas that do not have access to electricity grids. The integration of the generation of hybrid renewable power in remote and rural areas supplies the required power demand and mitigates emissions. Thus, this study reviews the latest literature (theses, journals articles, and conference proceedings) on the need for electricity in remote rural communities, on hybrid RE systems, on environmental impact, and on economic regulation in Malaysia. Power in this country is mainly generated by fossil fuels that emit high concentrations of greenhouse gases. Thus, RE is a potential alternative for to electrify rural areas, to meet current and future energy demands, and to mitigate emissions. Moreover, Malaysia has pledged to reduce its carbon-emission intensity by a maximum of 40 % (2005 level) by the year 2020. Therefore, the implementation of RE technologies in this country is significantly aided by RE projects, research and development activities, technologies, energy policies, and future direction. This review concludes that solar, wind, hydro, and biomass energy, as well as a hybrid of these, can effectively electrify rural areas. 相似文献
110.
Farhad Shir Catherine Mavriplis Lawrence H. Bennett Edward Della Torre 《International Journal of Refrigeration》2005,28(4):1082
Results of a room temperature magnetic refrigeration test bed and an analysis using a computational model are presented. A detailed demonstration of the four sequential processes in the transient magnetocaloric regeneration process of a magnetic material is presented. The temperature profile during the transient approach to steady state operation was measured in detail. A 5 °C evolution of the difference of temperature between the hot end and the cold end of the magnetocaloric bed due to regeneration is reported. A model is developed for the heat transfer and fluid mechanics of the four sequential processes in each cycle of thermal wave propagation in the regenerative bed combined with the magnetocaloric effect. The basic equations that can be used in simulation of magnetic refrigeration systems are derived and the design parameters are discussed. 相似文献