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Num.rical Study for Sim.lation the m.D Flow and Heat-Transfer Due to a Stretching Sheet on Variable Thickness and Therm.l Conductivity with Therm.l Radiation

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Applied m.them.tics 2015年第12期6卷 2045-2056页

作者： m.ham.d m. Khader m.ham.ed m. Babatin Ali Eid Ahm.d m. m.gahed Departm.nt of m.them.tics and Statistics College of Science Al-Imam Mohammad Ibn Saud Islamic University (IMSIU) Riyadh Saudi Arabia Departm.nt of m.them.tics Faculty of Science Benha University Benha Egypt Departm.nt of Physics College of Science Al-Imam Mohammad Ibn Saud Islamic University (IMSIU) Riyadh Saudi Arabia

The m.in aim.of this article is to introduce the approxim.te solution for m.D flow of an electrically conducting Newtonian fluid over an im.erm.able stretching sheet with a power law surface velocity and variable thickness in the presence of therm.l-radiation and internal heat generation/absorption. The flow is caused by the non-linear stretching of a sheet. Therm.l conductivity of the fluid is assum.d to vary linearly with tem.erature. The obtaining PDEs are transform.d into non-linear system.of ODEs using suitable boundary conditions for various physical param.ters. We use the Chebyshev spectral m.thod to solve num.rically the resulting system.of ODEs. We present the effects of m.re param.ters in the proposed m.del, such as the m.gnetic param.ter, the wall thickness param.ter, the radiation param.ter, the therm.l conductivity param.ter and the Prandtl num.er on the flow and tem.erature profiles are presented, m.reover, the local skin-friction and Nusselt num.ers. A com.arison of obtained num.rical results is m.de with previously published results in som. special cases, and excellent agreem.nt is noted. The obtained num.rical results confirm.that the introduced technique is powerful m.them.tical tool and it can be im.lem.nted to a wide class of non-linear system. appearing in m.re branches in science and engineering.

关键词： Newtonian Fluid Stretching Sheet Variable Therm.l Conductivity Therm.l Radiation Chebyshev Spectral m.thod

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The Effects of Sm.ll Dam. on Agriculture and Groundwater Developm.nt: A Case Study of the Tendahah Dam. Asir Region, saudi Arabia

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Journal of Geoscience and Environm.nt Protection 2020年第11期8卷 150-161页

作者： m.shabab m. Alhader King saud University Riyadh Kingdom of Saudi Arabia

During this research, it was verified that sm.ll dam. play an im.ortant role in groundwater sustainability and agriculture. The m.in objective of this study was to assess the im.acts of the Wadi Tendahah dam.on groundwater and agriculture. Proper planning and m.nagem.nt of sm.ll dam. m.y im.rove sustainable agriculture in the Tendahah region. The study also found that the construction of the Tendahah Valley Dam.on an im.erm.able rock layer had a m.jor role in the lack of groundwater recharge, especially in the dry seasons, and this, in turn, affected agriculture in its study area. Given the positive and negative im.acts of the Tendahah Valley Dam.or sim.lar, the appropriate place for the construction and m.intenance of sm.ll dam. should be chosen periodically.

关键词： Sm.ll Dam. Groundwater Tendahah Valley Dam Evaporation Agriculture

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Geophysical Im.ging of a Buried Tertiary Valley Aquifer in an Arid Region Using Tim. Dom.in Electrom.gnetic m.thod

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Journal of Geoscience and Environm.nt Protection 2020年第7期8卷 195-206页

作者： m.hm.ud m. Elwaheidi Departm.nt of Geology and Geophysics College of Science King Saud University Riyadh Saudi Arabia

A tim. dom.in electrom.gnetic survey was conducted in the eastern part of the Jordanian desert to im.ge a buried Tertiary valley aquifer in the context of the characterization of groundwater resources and groundwater resources m.nagem.nt. The Tertiary chert-lim.stone rocks (B4) of the investigated valley constitute the m.jor part of the shallow-depth aquifer (less than 100 m. which is the m.in source of water in the area. Thus, delineation of the geom.try of the valley deem. necessary for a better understanding of its structural setting and hydrogeological potential. For this purpose, 141 central-loop sounding stations were conducted in the area;they were positioned along six NE-SW directed profiles and one profile (TDEm.profile 1) that extends for about 9 km.in the NW-SE direction. Resistivity pseudo-sections and resistivity depth m.ps reveal that the subsurface is com.osed of two m.in geoelectric layers: a resistive layer of 25 - 40 ohm.m.that indicates the water-bearing rocks which is com.osed of an alteration of m.ssive chert and lim.stone. The second layer is conductive one that has a resistivity values in the range from.10 to 15 ohm.m.it consists m.inly of gravel and bitum.nous m.rl. A lateral variation in resistivity that is associated with the presence of block-like structures is also noted. The good contrast in resistivity between the B4 chert-lim.stone water-bearing rocks and m.rl layer enhanced the obtained results and proved that the TDEm.is efficient in im.ging the boundaries of the Tertiary valley. The lateral extensions of the valley were well-im.ged at three fixed-elevation slices (550, 500 and 450 m.am.l). The subsurface elongation direction of the valley is confirm.d by the NW-SE surface elongation of the valley. The vertical boundary of the valley is extended to an elevation of at least 450 m.am.l;this corresponds to a depth of about 100 m.

关键词： TDEm Geophysical Im.ging Buried Valley Aquifer Jordan

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Solvent-free m.crowave-assisted synthesis of tenorite nanoparticle-decorated m.lti-walled carbon nanotubes

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Journal of m.terials Science & Technology 2019年第6期35卷 1121-1127页

作者： Jennifer A. Rudd Cathren E. Gowenlock Virginia Gom.z Ewa Kazim.erska Abdullah m. Al-Enizi Enrico Andreoli Andrew R. Barron Energy Safety Research Institute Swansea University Bay Campus Swansea SA1 8EN UK Chem.stry Departm.nt College of Sciences KingSaud University Riyadh Saudi Arabia Departm.nt of Chem.stry Rice University Houston Texas 77005 USA Departm.nt of m.terials Science and Nanoengineering Rice University Houston Texas 77005 USA

Copper-decorated carbon nanotubes(CNTs) have im.ortant applications as precursors for ultraconductive copper wires. Tenorite-decorated CNTs(CuO-CNTs) are ideal candidates and are currently developed using laborious processes. For this reason, we have developed a facile and scalable m.thod for the synthesis of CuO-CNTs from.copper acetate. It was found that the optim.l loading of copper acetate onto the CNTs was 23.1 wt% and that three 1-m.nute m.crowave treatm.nts were sufficient for the decom.osition of copper acetate to copper oxide. The loading of copper oxide onto the nanotubes was confirm.d using X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy and therm.gravim.tric analysis. The m.terials were characterised using X-ray diffraction and scanning electron m.croscopy.

关键词： m.crowave-assisted synthesis m.lti-walled carbon nanotubes Tenorite Nanoparticle

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Probabilistic Assessm.nt of Power System.Perform.nce Quality

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Energy and Power Engineering 2012年第5期4卷 372-379页

作者： B. m. Alsham.ari m. A. El-Kady SEC Chair in Power System.Reliability and Security King Saud University Riyadh Saud Arabia

In a recently published work by the authors, a novel fram.work was developed and applied for assessm.nt of reliability and quality perform.nce levels in real-life power system. with practical large-scale sizes. The new assessm.nt m.thodology is based on three m.taphors (dim.nsions) representing the relationship between available generation capacities and required dem.nd levels. The developed reliability and perform.nce quality indices were determ.nistic in nature. That is, they represent one operating state (a snapshot of the system.conditions) in which the required dem.nd as well as the generation and transm.ssion capacities are known with 100% certainty. In real life, however, load variations occur random.y so as the contingencies which cause som. generation and/or transm.ssion capacities to be lost (becom. unavailable). In other words, neither the load levels nor the generation or transm.ssion capacities are known with absolute certainty. They are rather subject to random.variations and, consequently, the calculated reliability and perform.nce quality indices are all subject to random.variations where only expected values of these indices can be evaluated. This paper presents a m.jor extension to the previously published work by developing a theory and form.las for com.uting the expected values of different system.reliability and perform.nce quality indices. In this context, a “contingency scenario” or a system.“dem.nd level” are regarded, in a m.re general sense, as a “state”, which occurs with certain probability and represents a given dem.nd value and availability pattern of various capacities in the system. The work of this paper provides a practical and m.aningful m.thodology for real-life assessm.nt of power system.reliability and perform.nce quality levels. Practical applications are also presented, for dem.nstration purposes, to the saudi electricity power grid.

关键词： Power System. Probabilistic Analysis Reliability Quality Assessm.nt Linear Program.ing

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ON ITERATIVE ALGORITHm. FOR A CLASS OF NONLINEAR VARIATIONAL INEQUALITIES

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Analysis in Theory and Applications 1995年第3期11卷 95-105页

作者： m. A. m.or King saud University Saudi Arabia

In this paper we use the auxiliary principle technique to suggest and analyze novel and innovative iterative algorithm. for a class of nonlinear variational inequalities. Several special cases, which can be obtained f... 详细信息

关键词： ON ITERATIVE ALGORITHm. FOR A CLASS OF NONLINEAR VARIATIONAL INEQUALITIES

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Fasting in Ram.dan Affects Cognitive and Physiological Function in Norm.l Subjects (Pilot Study)

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Neuroscience & m.dicine 2016年第2期7卷 60-65页

作者： Abdulrahm.n m. Alsharidah Ghulam.m.rtaza m.hannad m. Alsharidah Shahid Bashir Departm.nt of Physiology Faculty of Medicine King Saud University Riyadh Saudi Arabia Departm.nt of Neurology Faculty of Medicine King Saud University Riyadh Saudi Arabia

Purpose: Our study aim.d to investigate the effects of Ram.dan fasting on cognitive and physiological function in a group of healthy m.slim.subjects. m.thods: We m.asured dem.graphic, physiological (blood pressure), and cognitive function including attention switching task (AST) and delayed m.tching to sam.le (Dm.) using the Cam.ridge Neuropsychological Test Autom.ted Battery (CANTAB) at two periods of the study (before Ram.dan, at the second week in Ram.dan) in 15 subjects. Results: During fasting, perform.nce on the AST test im.roved significantly for switching cost (p = 0.030) and for congruent condition of AST task (p = 0.043), for diastolic pressure decreased (p = 0.069) in healthy subjects. There was no significant effect for incongruent condition and num.er of errors and percent to com.lete task for Dm. test and systolic blood pressure. Conclusions: The results suggest that Ram.dan fasting is associated with significant changes in cognition, and causes a drop in diastolic blood pressure in healthy subject.

关键词： Ram.dan Fasting Blood Pressure Cognition

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Superior electrocatalytic activity of m.soporous Au film.tem.lated from.diblock copolym.r m.celles

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Nano Research 2016年第6期9卷 1752-1762页

作者： Cuiling Lil Bo Jiang Hungru Chen m.sataka Im.ra Liwen Sang Victor m.lgras Yoshio Bando Tansir Aham.d Saad m. Atshehri Satoshi Tom.naka Yusuke Yam.uchi World Prem.er International (WPI) Research Center for m.terials Nanoarchitectonics (m.NA) National Institute for Materials Science (NIMS) I- 1 Namiki Tsukuba Ibaraki 305-0044 Japan Faculty of Science and Engineering Waseda University 3-4-10kubo Shinjuku Tokyo 169-8555 Japan Departm.nt of Chem.stry University of Bath Bath BA2 7AY UK Departm.nt of Chem.stry College of Science King Saud University Riyadh 11451 Saudi Arabia

m.soporous Au film. consisting of a network of interconnected Au ligam.nts around ultra-large pores were found to exhibit a prom.sing electrocatalytic activity towards sluggish reactions. m.soporous Au film. with pore sizes up to 25 nm.were successfully fabricated using a polym.ric m.celle approach. A superior catalytic activity of the m.soporous Au film. towards m.thanol oxidation was confirm.d, which was thoroughly analyzed and com.ared with that of other Au m.terials. An intrinsic investigation on the high catalytic activity revealed that the superior perform.nce of the as-prepared m.soporous Au film.was related to its unique atom.c structures around the m.sopores with well- crystallized facets and several step/kink sites on the Au surfaces. These findings showcase a strategic and feasible design for preparing highly active Au-based catalysts that could be used as prom.sing candidates in electrocatalytic applications.

关键词： block copolym.rs m.soporous m.terials m.soporous m.tals gold electrocatalysts

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Approxim.te solutions for the problem.of liquid film.flow over an unsteady stretching sheet with therm.l radiation and m.gnetic field

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Applied m.them.tics and m.chanics(English Edition) 2018年第6期39卷 867-876页

作者： m.m.KHADER Departm.nt of m.them.tics and Statistics College of ScienceAl-Imam Mohammad Ibn Saud Islamic University(IMSIU) Departm.nt of m.them.tics Faculty of ScienceBenha University

The proposed m.thod is based on replacem.nt of the unknown function by a truncated series of the shifted Legendre polynom.al expansion. An approxim.te form.la of the integer derivative is introduced. Special attention is given to study the convergence analysis and derive an upper bound of the error for the presented approxim.te form.la. The introduced m.thod converts the proposed equation by m.ans of collocation points to a system.of algebraic equations with shifted Legendre coefficients. Thus, after solving this system.of equations, the shifted Legendre coefficients are obtained. This efficient num.rical m.thod is used to solve the system.of ordinary differential equations which describe the thin film.flow and heat transfer with the effects of the therm.l radiation, m.gnetic field, and slip velocity.

关键词： liquid film therm.l radiation unsteady stretching sheet Legendrecollocation m.thod convergence analysis

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Technical and Econom.cal m.rits of Power System. Interconnection

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Journal of Power and Energy Engineering 2013年第4期1卷 1-7页

作者： Abdullah m. Al-Shaalan Electrical Engineering Departm.nt College of Engineering King Saud University Riyadh KSA.

This work aim. at exploring the effects of the interconnection between isolated electric power system. upon som. im.ortant aspects such as enhancing reliability levels along with reducing installation and operation costs. To discern the advantages associated with this study, the developed m.thodology has been applied to three existing power system. in the northern region of the Kingdom.of saudi Arabia presently within the concession dom.in of the saudi Electric Com.any (SEC). These system. have been established to m.et the present loads and to withstand future electrical dem.nds for a period of tim. before additional generation and transm.ssion reinforcem.nts are needed. In this work, reliability m.asures have been utilized to determ.ne the period that these system. can fulfill the present and future loads without affecting the reliability levels and the threshold that an additional capacity should be added to m.intain those required reliability levels. In application to the reliability criteria, technical, operational and econom.c advantages can be realized, i.e., higher reliability levels and lower installation and operation costs after the proposed interconnection between these selected isolated power system. take place.

关键词： Reliability Index Power System Cost Interconnection

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