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Numerical simulation of compression corner flows at Mach number 9

Chinese Journal of Aeronautics 2020年第6期33卷 1611-1624页

作者： Amjad APASHA khalid AJUHANY Department of Aerospace Engineering King Abdulaziz UniversityJeddah 21589Saudi Arabia

A hypersonic vehicle encounters a wide range of conditions during its complete flight *** flight conditions may vary from low to high Mach numbers with varying angles of *** near-wall viscous dissipation associated with flows at combined high Mach and Reynolds numbers leads to significant wall heat transfer rates and shear *** shock wave/boundary-layer interaction results in a flow separation region,which commonly augments total pressure losses in the flow and lowers the efficiency of aerodynamic control surfaces such as fins installed on a *** standard turbulence models,when used to resolve such flows,result in incorrect separation bubble size for large separated ***,it results in an inaccurate aerodynamic load,such as the wall pressures,skin friction distribution,and heat transfer *** previous studies,the application of the shock-unsteadiness correction to the standard two-equation k-ωturbulence model improved the separation bubble size leading to an accurate pressure prediction and shock definition with the assumption of constant Prandtl *** the present work,the new shock-unsteadiness modification to the k-ωturbulence model is applied to the hypersonic compression corner *** new model with variable Prandtl number is based on the model parameter,which depends upon the local density *** computed wall pressures,heat flux and flow field are compared to the experimental data.A parametric study is carried out by varying compression deflection angles,free stream Reynolds number and wall temperatures to compute the flow field and wall data accurately,particularly in the shock boundary layer interaction *** new shockunsteadiness modified k-ωmodel with variable Prandtl number shows an accurate prediction of initial pressure rise location,pressure distribution in the plateau region and heat flux in comparison to the standard k-ωmodel.

关键词： Boundary layer Expansion fan Heat transfer Hypersonic flows Separation length Shock-unsteadiness model Shock wave Turbulence model Turbulent Prandtl number

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Characteristics of newly-formed cementum following emdogain application

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International Journal of Oral Science 2011年第1期3卷 21-26页

作者： khalid al-Hezaimi Mansour al-Askar Abdulaziz al-Rasheed Eng.A.B.Bagshan Growth Factors and Bone Regeneration Research Chair King Saud UniversityRiyadhSaudi Arabia Department of Periodontology School of Dentistry King Saud UniversityRiyadh Saudi Arabia Eng.A.B.Bagshan Growth Factors and Bone Regeneration Research Chair King Saud UniversityRiyadh Saudi Arabia Department of Periodontology School of Dentistry King Saud UniversityRiyadhSaudi Arabia

Periodontal regenerative techniques have been proposed; however, the outcomes remain debatable. The present investigation assessed the regenerated cementum following enamel matrix derivative application in dehiscence-type defects. Buccal osseous dehiscences were surgically created on the maxillary cuspid, and the second and fourth premolars in five female beagle dogs. The treatment group （n=15 sites） received the enamel matrix derived application, whereas the control groups （n=15） did not. The dogs were sacrificed 4 months following treatment and the specimens were histologically and histometrically examined. The newly formed cementum was uneven in thickness and mineralization, overlapped the old cementum and exhibited functional orientation, cementocyte lacunae and collagen fibril bundles. Most of the histological specimens showed the presence of a gap between the newly formed cementum and the underlying dentin. Control sites did not exhibit any cementum formation. The present study concluded that newly formed cementum is of cellular type and exhibits multiple characteristics.

关键词： regeneration cementum enamel matrix protein

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CNR:A Cluster-Based Solution for Connectivity Restoration for Mobile WSNs

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Computers, Materials & Continua 2021年第12期69卷 3413-3427页

作者： Mahmood ul Hassan Amin al-Awady khalid Mahmood Shahzad ali Ibrahim algamdi Muhammad Kashif Saeed Safdar Zaman Department of Computer Skills Najran UniversityNajran66241Saudi Arabia Department of Information Systems College of Science and ArtsKing Khalid UniversityMahayil Asir63317Saudi Arabia Department of Computer Science Jouf UniversityTabarjal76769Saudi Arabia Department of Computer Science Community College Mahayil AsirKing Khalid UniversityMahayil63317Saudi Arabia Federal Directorate of Education Department of Computer ScienceIslamabad44000Pakistan

Wireless Sensor Networks(WSNs)are an integral part of the Internet of Things(IoT)and are widely used in a plethora of ***,sensor networks operate in harsh environments where human intervention is often restricted,which makes battery replacement for sensor nodes *** failure due to battery drainage or harsh environmental conditions poses serious challenges to the connectivity of the *** a connectivity restoration mechanism,node failures ultimately lead to a network partition,which affects the basic function of the sensor ***,the research community actively concentrates on addressing and solving the challenges associated with connectivity restoration in sensor *** energy is a scarce resource in sensor networks,it becomes the focus of research,and researchers strive to propose new solutions that are energy *** common issue that is well studied and considered is how to increase the network’s life span by solving the node failure problem and achieving efficient energy *** paper introduces a Clusterbased Node Recovery(CNR)connectivity restoration mechanism based on the concept of *** is a well-known mechanism in sensor networks,and it is known for its energy-efficient operation and *** proposed technique utilizes a distributed cluster-based approach to identify the failed nodes,while Cluster Heads(CHs)play a significant role in the restoration of *** simulations were conducted to evaluate the performance of the proposed technique and compare it with the existing *** simulation results show that the proposed technique efficiently addresses node failure and restores connectivity by moving fewer nodes than other existing connectivity restoration *** proposed mechanism also yields an improved field coverage as well as a lesser number of packets exchanged as compared to existing state-of-the-art mechanisms.

关键词： WSNs CHs CNR transmission range connectivity restoration node failure cluster communication range

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Design, Synthesis and Pharmacological Evaluation of New Nonsteroidal Anti-Inflammatory Derived from 3-Aminobenzothieno[2,3-<i>d</i>]pyrimidines

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International Journal of Organic Chemistry 2013年第2期3卷 110-118页

作者： Hend Nagah Hafez omar khalid al-Duaij Abdel-Rhman Barakat A. El-Gazzar Chemistry Department Faculty of Science Al-Imam Mohammad Ibn Saud Islamic University (IMSIU) Riyadh KSA Photochemistry Department National Research Centre Cairo Egypt

During the last few years, condensed thienopyrimidine derivatives have received considerable attention. The therapeutic importance of thienopyrimidines prompted us to synthesize some of spiro(benzothieno[2,3-d]pyrimidine-4-one) derivatives. Some of the novel benzothino-pyrimidine derivatives 3a, 9b, 10b, 11a, 11b, and 11c showed considerable potent anti-inflammatory and analgesic activity of superior G.I.T. safety profile in experimental rats in comparing to indomethacin and tramadol as reference drugs.

关键词： Spirobenzothienopyrimidine Triazolopyrimidine Pyrazolopyrimidine Analgesic Anti-inflammatory Ulcerogenic Effect

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Impact of silver sulphides on gold cyanidation with polymetal sulphides

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Transactions of Nonferrous Metals Society of China 2018年第3期28卷 542-555页

作者： Muhammad khalid Faical LARACHI Department of Chemical Engineering Laval UniversityQuébecQCG1V 0A6Canada

Gold leaching was influenced in association with silver and polymetal sulphide minerals.A packed bed was adopted to single out the galvanic and passivation effects with four sets of minerals:pyrite?silica,chalcopyrite?silica,sphalerite?silica and stibnite?*** enhanced Au recovery to 77.3%and 51.2%under galvanic and passivation effects from pyrite(vs 74.6%and 15.8%).Pyrargyrite in association with sphalerite also enhanced Au recovery to 6.6%and 51.9%(vs 1.6%and 15.6%)under galvanic and passivation effects from *** associated with chalcopyrite retarded gold recovery to 38.0%and 12.1%(vs 57%and 14.1%)under galvanic and passivation *** silver minerals enhanced Au recovery to 90.6%and 81.1%(vs 74.6%and 15.8%)under galvanic and passivation impacts from *** minerals with sphalerite under galvanic and passivation effects enhanced Au recovery to 71.1%and 80.5%(vs 1.6%and 15.6%).Silver minerals associated with chalcopyrite retarded Au recovery to 10.2%and 4.5%under galvanic and passivation impacts(vs 57%and 14.1%).Stibnite retarded Au dissolution with pyrargyrite and accumulative silver *** and accumulative silver enhanced gold dissolution for free gold and gold associated with pyrite and *** dissolution was retarded for gold and silver minerals associated with chalcopyrite and stibnite.

关键词： silver mineral gold cyanidation packed-bed reactor sulphide mineral passivation galvanic interaction

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Sentinel-2 Satellite Imagery Application to Monitor Soil Salinity and Calcium Carbonate Contents in Agricultural Fields

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Phyton-International Journal of Experimental Botany 2023年第5期92卷 1603-1620页

作者： Ahmed M.Zeyada khalid A.al-Gaadi ElKamil Tola Rangaswamy Madugundu Ahmed A.alameen Department of Agricultural Engineering College of Food and Agriculture SciencesKing Saud UniversityRiyadh11451Saudi Arabia Precision Agriculture Research Chair Deanship of Scientific ResearchKing Saud UniversityRiyadh11451Saudi Arabia

The estuary tides affect groundwater dynamics;these areas are susceptible to waterlogging and salinity issues.A study was conducted on two fields with a total area of 60 hectares under a center pivot irrigation system that works with solar energy and belong to a commercial farm located in Northern *** monitor soil salinity and calcium carbonate in the area and stop future degradation of soil resources,easy,non-intrusive,and practical procedures are *** objective of this study was to use remote sensing-determined Sentinel-2 satellite imagery using various soil indices to develop prediction models for the estimation of soil electrical conductivity(EC)and soil calcium carbonate(CaCO_(3)).Geo-referenced soil samples were collected from 72 locations and analyzed in the laboratory for soil EC and CaCO_(3).The electrical conductivity of the soil saturation paste extract was represented by average values in soil dataset samples from two fields collected from the topsoil layer(0 to 15 cm)characteristic of the local salinity *** various soil indices,used in this study,were calculated from the Sentinel-2 satellite *** prediction was determined using the root mean square error(RMSE)and cross validation was done using coefficient of *** results of regression analysis showed linear relationships with significant correlation between the EC analyzed in laboratory and the salinity index-2“SI2”(Model-1:R^(2)=0.59,p=0.00019 and root mean square error(RMSE=1.32%)and the bare soil index“BSI”(Model-2:R^(2)=0.63,p=0.00012 and RMSE=6.42%).Model-1 demonstrated the best model for predicting soil EC,and validation R^(2)and RMSE values of 0.48%and 1.32%,*** regression analysis results for soil CaCO_(3)determination showed linear relationships with data obtained in laboratory and the bare soil index“BSI”(Model-3:R^(2)=0.45,p=0.00021 and RMSE=1.29%)and the bare soil index“BSI”&Normalized difference salinity index“NDSI”(Model-4:R^(2)=0.53,

关键词： Electrical conductivity modeling soil indices remote sensing prediction

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Analysis and Assessment of Wind Energy Potential of al-Hodeidah in Yemen

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Computers, Materials & Continua 2021年第11期69卷 1995-2011页

作者： Fahd N.al-Wesabi Murad A.almekhlafi Mohammed Abdullah al-Hagery Mohammad alamgeer khalid Mahmood Majdy M.Eltahir ali M.al-Sharafi Amin M.El-Kustaban Department of Computer Science King Khalid UniversityMuhayel AseerKingdom of Saudi Arabia Faculty of Computer and IT Sana’a UniversitySana’aYemen Department of Electrical Engineering–Communication Engineering Sana’a UniversityYemen Department of Computer Science College of ComputerQassim UniversitySaudi Arabia Department of Information Systems King Khalid UniversityMayahel AseerKSA Department of Computer Science College of Computers and Information TechnologyUniversity of BishaKSA Department of Electronic Faculty of EngineeringUSTSana’aYemen

Renewable energy is one of the essential elements of the social and economic development in any civilized *** use of fossil fuels and the non-renewable form of energy has many adverse effects on the most of *** the high potential of renewable energy sources in Yemen and the absence of similar studies in the region,this study aimed to examine the wind energy potential of Hodeidah-Yemen Republic by analyzing wind characteristics and assessment,determining the available power density,and calculate the wind energy extracted at different *** average wind speed of Hodeidah was obtained only for the data currently available for the five years 2005–2009(due to the current economic and the political situation in Yemen).The results show that the average wind speed in the five years is(25.2 W/m2 at 10 m,93.9 W/m2 at 30 m,and 173.5 W/m2 at 50 m).The average yearly wind power density(25.2 W/m2 at 10 m,93.9 W/m2 at 30 m and 173.5 W/m2 at 50m),and the average yearly energy density(220.8 KWh/m2/year at 10 m,822.6 KWh/m2/year at 30 m and 1519.9 KWh/m2/year at 50 m).This research is a preliminary assessment of the potential of wind energy in Hodeidah,which provides useful information for developing wind energy and an efficient wind *** to the International Wind Energy Rating criteria,the region of Hodeidah falls under‘Class 2’and is classified as‘Marginal’for most of the year.

关键词： Energy potential wind speed weibull distribution wind power density

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An Efficient Connectivity Restoration Technique(ECRT)for Wireless Sensor Network

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Computers, Materials & Continua 2021年第10期69卷 1003-1019页

作者： Mahmood ul Hassan Shahzad ali khalid Mahmood Muhammad Kashif Saeed Amin al-Awady Kamran Javed Ansar Munir Shah Department of Computer Skills Preparatory yearNajran UniversityNajran66241Saudi Arabia Department of Computer Science Jouf UniversityTubarjal74769Saudi Arabia Department of Information Systems College of Science and ArtsKing Khalid UniversityMahayil Asir63317Saudi Arabia Department of Computer Science Community College Mahayil AsirKing Khalid UniversityMahayil63718Saudi Arabia Department of Computer Engineering National University of Technology(NUTECH)Islamabad44000Pakistan Department of Computer Science Institute of Southern PunjabMultan60000Pakistan

Node failure in Wireless Sensor Networks(WSNs)is a fundamental problem because WSNs operate in hostile *** failure of nodes leads to network partitioning that may compromise the basic operation of the sensor *** deal with such situations,a rapid recovery mechanism is required for restoring inter-node *** to the immense importance and need for a recovery mechanism,several different approaches are proposed in the ***,the proposed approaches have shortcomings because they do not focus on energy-efficient operation and coverage-aware mechanisms while performing connectivity ***,most of these approaches rely on the excessive mobility of nodes for restoration connectivity that affects both coverage and energy *** paper proposes a novel technique called ECRT(Efficient Connectivity Restoration Technique).This technique is capable of restoring connectivity due to single and multiple node *** achieves energy efficiency by transmitting a minimal number of control *** is also coverage-aware as it relocates minimal nodes while trying to restore *** the help of extensive simulations,it is proven that ECRT is effective in connectivity restoration for single and multiple node *** also show that ECRT exchanges a much smaller number of packets than other ***,it also yields the least reduction in field coverage,proving its versatility for connectivity restoration.

关键词： Cut-vertex failure recovery network connectivity node relocation wireless sensor network node failures

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Assessment of the properties of polycrystalline rock salt synthesized under nominally dry and wet conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 311-320页

作者： Amirsalar Moslehy khalid alshibli Department of Civil and Environmental Engineering University of TennesseeKnoxvilleTN37996USA

Polycrystalline rock salt’s compression is a function of applied stresses,exposure duration to the applied stresses,ambient temperature,and water *** salt’s compressional behavior under different conditions and its effects on the specimens’mechanical properties have been investigated in the ***,the one-dimensional(1D)compression behavior of polycrystalline rock salt at various water contents and how the specimen’s compression at different water contents further affects its physical and mechanical properties are not fully understood *** this study,polycrystalline rock salt specimens were prepared under nominally dry and wet conditions and some of the dry and wet specimens were annealed after the *** relationship between the porosity of the specimens and the logarithm of the applied axial stresses during the 1D compression was found to follow a linear relationship after reaching unique critical porosities of 32%and 37%for the dry and wet specimens,*** and reloading the specimens did not result in any major changes in the porosity of the *** specimens compressed under wet condition showed an average final porosity of 2.6%compared to 6.9%for the dry *** dry and wet specimens that were annealed after the compression exhibited a lower porosity in comparison to the dry and wet specimens,*** compression experiments on the specimens showed dry and wet specimens possess averaged unconfined compressive strengths(σ_(u))of 64.3 and 16.2 MPa,*** decreased σ_(u)of the dry specimens to 39.6 MPa and increased σ_(u)of the wet specimens to 41 MPa.

关键词： Halite Rock salt Unconfined compression One-dimensional(1D)compression

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Modulating microRNAs in cancer: next-generation therapies

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Cancer Biology & Medicine 2022年第3期19卷 289-304页

作者： Nahid Arghiani khalid Shah Center for Stem Cell and Translational Immunotherapy(CSTI) Harvard Medical SchoolBostonMA 02115USA Department of Neurosurgery Brigham and Women’s HospitalHarvard Medical SchoolBostonMA 02115USA Harvard Stem Cell Institute Harvard UniversityCambridgeMA 02138USA

MicroRNAs(miRNAs)are a class of endogenously expressed non-coding regulators of the genome with an ability to mediate a variety of biological and pathological *** is growing evidence demonstrating frequent dysregulation of microRNAs in cancer cells,which is associated with tumor initiation,development,migration,invasion,resisting cell death,and drug *** have shown that modulation of these small RNAs is a novel and promising therapeutic tool in the treatment of a variety of diseases,especially cancer,due to their broad influence on multiple cellular ***,suboptimal delivery of the appropriate miRNA to the cancer sites,quick degradation by nucleases in the blood circulation,and off target effects have limited their research and clinical ***,there is a pressing need to improve the therapeutic efficacy of miRNA modulators,while at the same time reducing their *** delivery vehicles for miRNA modulators have been shown to be effective in vitro and in *** this review,we will discuss the role and importance of miRNAs in cancer and provide perspectives on currently available carriers for miRNA *** will also summarize the challenges and prospects for the clinical translation of miRNAbased therapeutic strategies.

关键词： MiRNAs dysregulation delivery systems cancer therapy clinical translation

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