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Topological evolution of laminar juncture flows under different critical parameters

Science China(Technological Sciences) 2014年第7期57卷 1342-1351页

作者： YOUNIS Muhammad Yamin ZHANG Hua HU Bo mehmood saqib National Key Laboratory of Fluid Mechanics School of Aeronautical Science and Engineering Beihang University School of Astronautics Beihang University

Horseshoe vortex topological structure has been studied extensively in the past,traditional"saddle of separation"and new"attachment saddle point"topologies found in literature both have theoretical basis and experimental and computational evidences for *** laminar incompressible juncture flows at low Reynolds numbers especially are observed to have new *** concerning the existence of the new topology though found in literature,the topological evolution and its dependency on various critical flow parameters require further investigation.A Particle Image Velocimetry based analysis is carried out to observe the effect of aspect ratio,?*/D and shape of the obstacle on laminar horseshoe vortex topology for small *** in aspect ratio evolves the topology from the traditional to new for all the cases *** circular cross section obstacles are found more apt to having the new topology compared to square cross *** is noted that the sweeping effect of the fluid above the vortex system in which horseshoe vortex is immersed plays a critical role in this *** evolution is observed not only in the most upstream singular point region of horseshoe vortex system but also in the corner *** corner vortex topology evolves from the traditional type to new one before the topological evolution of the most upstream singular point,resulting in a new topological pattern of the laminar juncture flows"separation-attachment combination".The study may help extend the understanding of the three-dimensional boundary layer separation phenomenon.

关键词： horseshoe vortex saddle of attachment saddle of separation topological evolution sweeping effect

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Geochemistry and Tectonic Settings of Felsic Dykes in the Neoproterozoic Nagar Parkar Igneous Complex, SE Sindh, Pakistan

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Acta Geologica Sinica(English Edition) 2016年第S1期90卷 124-页

作者： Tahseenullah Khan Mamoru Murata M.Qasim Jan Hafiz Ur Rehman Muhammad Zafar Hiroaki Ozawa Anwar Qadir saqib mehmood Department of Earth and Environmental Sciences Bahria University Department of Geosciences Faculty of Science Naruto University of Education National University Corporation National Centre of Excellence in Geology University of Peshawar and COMSTECH Islamabad Department of Earth and Environmental Science Faculty of Science Kagoshima University International Cooperation Center for the Teacher Education and Training Naruto University of Education Department of Geology Haripur University

The Nagar Parkar complex consists of Neoproterozoic igneous and metamorphic rocks dissected by episodic mafic and felsic *** latter can be classified broadly into porphyritic felsic dykes and aplitic felsic dykes(minor)

关键词： SE Sindh Pakistan Geochemistry and Tectonic Settings of Felsic Dykes in the Neoproterozoic Nagar Parkar Igneous Complex

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Distribution and leaching characteristics of trace elements in ashes as a function of different waste fuels and incineration technologies

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Journal of Environmental Sciences 2015年第10期27卷 9-21页

作者： Naeem saqib Mattias Backstrom Department of Science and Technology Man-Technology-Environment Research Centreorebro University

Impact of waste fuels（virgin/waste wood, mixed biofuel（peat, bark, wood chips） industrial,household, mixed waste fuel） and incineration technologies on partitioning and leaching behavior of trace elements has been investigated. Study included 4 grate fired and 9 fluidized boilers. Results showed that mixed waste incineration mostly caused increased transfer of trace elements to fly ash; particularly Pb/Zn. Waste wood incineration showed higher transfer of Cr,As and Zn to fly ash as compared to virgin wood. The possible reasons could be high input of trace element in waste fuel/change in volatilization behavior due to addition of certain waste fractions. The concentration of Cd and Zn increased in fly ash with incineration *** concentration in ashes decreased in order of Zn 〉 Cu 〉 Pb 〉 Cr 〉 Sb 〉 As 〉 Mo. The concentration levels of trace elements were mostly higher in fluidized boilers fly ashes as compared to grate boilers（especially for biofuel incineration）. It might be attributed to high combustion efficiency due to pre-treatment of waste in fluidized boilers. Leaching results indicated that water soluble forms of elements in ashes were low with few *** levels in ash and ash matrix properties（association of elements on ash particles）are crucial parameters affecting leaching. Leached amounts of Pb, Zn and Cr in 〉50% of fly ashes exceeded regulatory limit for disposal. 87% of chlorine in fly ashes washed out with water at the liquid to solid ratio 10 indicating excessive presence of alkali metal chlorides/alkaline earths.

关键词： Incineration residues Leaching behavior Biofuel incineration Metal distribution Waste incineration

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Theoretical study of reactive melt infiltration to fabricate Co-Si/C composites

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Chinese Physics B 2021年第11期30卷 434-439页

作者： saqib Shahzad Khurram Iqbal Zaheer Uddin Department of Physics University of KarachiKarachiSindh 75270Pakistan College of Computer Science and Information Systems Institute of Business Management(IoBM)KarachiSindh 75190Pakistan

Cobalt-silicon based carbon composites(Co–Si/C)have established a noteworthy consideration in recent years as a replacement for conventional materials in the automotive and aerospace *** achieve the composite,a reactive melt infiltration process(RMI)is used,in which a melt impregnates a porous preform by capillary *** method promises a high-volume fraction of reinforcement and can be steered in such a way to get the good“near-net”shaped components.A mathematical model is developed using reaction-formed Co–Si alloy/C composite as a prototype system for this *** wetting behavior and contact angle are discussed;surface tension and viscosity are calculated by Wang’s and Egry’s equations,*** radii of 5μm and 10μm are set as a reference on highly oriented pyrolytic *** graphs are plotted using the model,to study some aspects of the infiltration *** highlights the possible connections among the various *** this attempt,the Co–Si(62.5 at.%silicon)alloy’s maximum infiltration at 5μm and 10μm radii are found as 0.05668 m at 125 s and 0.22674 m at 250 s,respectively.

关键词： cobalt-silicon/carbon composites Co-Si alloy reactive melt infiltration(RMI) carbon preforms

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Exploring the asymmetric impact of economic complexity,FDI,and green technology on carbon emissions:Policy stringency for clean-energy investing countries

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Geoscience Frontiers 2024年第4期15卷 459-473页

作者： Najia saqib Gheorghița Dinca Department of Finance College of Business AdministrationPrince Sultan UniversityRiyadhKingdom of Saudi Arabia Department of Finance and Accounting Transilvania University of BrașovBrașovRomania

All economies are concerned about rising carbon emissions,which contribute to environmental *** current paper formulates a novel framework to scrutinize the impacts of shocks in economic complexity,FDI,environmental technology,and renewable energy on carbon emission in the leading clean energy investment countries,spanning the period from 1995 to *** spite of the constraint for better environmental defence and the realization of the Sustainable Development Goals(SDGs),this paper introduces an empirical approach utilizing the Panel NARDL methodology to investigate the asymmetrical connections between carbon emissions and relevant exogenous ***,we utilize additional techniques,namely AMG and CCEMG,to enhance the robustness of our *** empirical findings reveal that positive shocks in economic complexity,FDI,environmental technology,and renewable energy reduce carbon emissions while negative shocks may result to elevated pollution levels in the ***,adverse shocks in economic complexity and FDI cause increased pollution in the long ***,the short-run coefficient signs are also similar to the longrun coefficient signs but different in significance level and *** has paved the way for a well-designed policy for leading clean-energy investment countries should focus on structural change,FDI,technology and renewable energy consumption.

关键词： Renewable energy Economic complexity NARDL Environmental technology SDGs Carbon emission FDI

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Global export flow of Chilean copper:The role of environmental innovation and renewable energy transition

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Geoscience Frontiers 2024年第3期15卷 336-345页

作者： Shujaat Abbas Najia saqib Umer Shahzad Graduate School of Economics and Management Ural Federal UniversityRussian Federation Brandenburg University of Technology Chair of Energy EconomicsGermany Adnan Kassar School of Business Lebanese American UniversityBeirutLebanon MEU Research Unit Middle East UniversityAmmanJordan Department of Finance College of Business AdministrationPrince Sultan UniversityRiyadhSaudi Arabia Department of Trade and Finance Faculty of Economics and ManagementCzech University of Life Sciences Prague

Copper is one of the most important minerals that has extensive use in environment-friendly technologies and renewable energy *** global urgency for environmental and ecological conservation through renewable energy transition has considerably enhanced the importance of copper and articles *** is a major producer of *** contributes more than one-third to global ***,this study explores the export flow of Chilean copper in response to increasing demand side conditions in major 24 trading partners from 2002 to *** objective is realized by constructing an augmented model for import demand that incorporates bilateral real exchange rate along with real GDP,environmental innovation,and renewable energy transition in major import *** estimated results of panel quantiles via moments techniques reveal a significant positive impact with increasing coefficients at higher quantiles,while environmental innovation and renewable energy transition in trading partners show significant positive impact with decreasing values of coefficients at higher *** findings urge Chile to enhance production capacity of copper and other critical mineral and improve participation in global value chain to meet sharply increasing copper demand from environmental innovation and renewable energy transition.

关键词： Copper Export flow Renewable energy Environmental innovation Panel data Quantiles via moments

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Investigating the implications of technological innovations,financial inclusion,and renewable energy in diminishing ecological footprints levels in emerging economies

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Geoscience Frontiers 2023年第6期14卷 341-357页

作者： Najia saqib Ilhan Ozturk Muhammad Usman Department of Finance College of Business AdministrationPrince Sultan UniversityRiyadhSaudi Arabia College of Business Administration University of SharjahSharjahUAE Faculty of Economics Administrative and Social SciencesNisantasi UniversityIstanbulTurkey School of Economics and Management and Center for Industrial EconomicsWuhan UniversityWuhan430072China

The correlation between technological innovation,economic growth,renewable energy,and ecological footprint carries significant policy implications for environmental ***,financial inclusion can drastically affect the technology-climate nexus across different countries and its moderating impacts have received sufficient *** do this,this study examined how technological innovation,financial inclusion,economic growth,and renewable energy affected emerging economies’ecological footprint from 1990 to ***,this study also scrutinizes the moderating role of financial inclusion with other regressors on ecological *** account for structural shifts,disguised cointegration,and numerous breaks in panel regression,this study applies advanced panel estimation methods for empirical *** estimated outcomes exhibit that the influence of technical innovation,climate technologies,and renewable energy significantly reduces the ecological footprint ***,economic growth and financial inclusion significantly increase the ecological footprint levels in the emerging ***,the integration of innovative technology and renewable energy in emerging countries mitigates the adverse effects of financial inclusion by making it easier for creative technologies and reducing ecological *** results show that emerging countries’innovative technology and renewable energy sources should be integrated with financial inclusion to enable longterm mitigation of environmental damages and sustainable *** on these estimated findings,the research recommends that emerging economies should hasten technological innovations along with stronger financial development to curtail ecological concerns without hindering the pace of sustainable economic growth.

关键词： Environmental-related technology Financial inclusion Renewable energy Ecological footprints Emerging countries

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TRUSED:A Trust-Based Security Evaluation Scheme for A Distributed Control System

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Computers, Materials & Continua 2023年第2期74卷 4381-4398页

作者： saqib Ali Raja Waseem Anwar Sultan Qaboos University Muscat123Sultanate of OMAN Arab Open University Muscat130Sultanate of OMAN

Distributed control systems(DCS)have revolutionized the communication process and attracted more interest due to their pervasive computing nature(cyber/physical),their monitoring capabilities and the benefits they ***,due to distributed communication,flexible network topologies and lack of central control,the traditional security strategies are inadequate formeeting the unique characteristics ***,malicious and untrustworthy nodes pose a significant threat during the formation of a DCS ***-based secure systems not only monitor and track the behavior of the nodes but also enhance the security by identifying and isolating the malicious node,which reduces the risk and increases network *** this research,we offer TRUSED,a trust-based security evaluation scheme that both,directly and indirectly,estimates each node’s level of trustworthiness,incorporating the cumulative trust *** addition,simulation results show that the proposed technique can effectively identify malicious nodes,determine their node’s trustworthiness rating,and improve the packet delivery ratio.

关键词： Malicious network lifetime risk management security trust untrustworthy

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Morphological and electrical properties of SrTiO3/TiO2/SrTiO3 sandwich structures prepared by plasma sputtering

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Chinese Physics B 2017年第1期26卷 156-159页

作者： saqib Jabbar Riaz Ahmad Paul K Chu Government College University Lahore 54000 Pakistan Department of Physics and Materials Science City University of Hong Kong Kowloon Hong Kong China

SrTiO3（STO） and TiO2 are insulating materials with large dielectric constants and opposite signs of the quadratic coefficient of voltage（α）. Insertion of a TiO2 thin film between STO layers increases the linearity of the capacitance in response to an applied voltage, to meet the increasing demand of large-capacitance-density dynamic random access memory capacitors. Both STO and TiO2 suffer from the problem of high leakage current owing to their almost equivalent and low bandgap energies. To overcome this, the thickness of the thin TiO2 film sandwiched between the STO films was varied. A magnetron sputtering system equipped with radio frequency and direct current power supply was employed for depositing the thin films. Ti N was deposited as the top and bottom metal electrodes to form a metal–insulator metal（MIM） structure,which exhibited a very large linear capacitance density of 21 fF/um-2 that decreased by increasing the thickness of the TiO2 film. The leakage current decreased with an increase in the thickness of TiO2, and for a 27-nm-thick film, the measured leakage current was 2.0 × 10^-10 A. X-ray diffraction and Raman spectroscopy revealed that Ti N, STO, and TiO2 films are crystalline and TiO2 has a dominant anatese phase structure.

关键词： strontium titanate Raman spectroscopy plasma deposition MIM capacitor

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Thirty years of chronic current account deficit 1972—2001: The case of Pakistan

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Journal of Harbin Institute of Technology(New Series) 2006年第5期13卷 559-563页

作者： saqib Gulzar 惠晓峰 School of Management Harbin Institute of Technology Harbin 150001 China

Pakistan has been suffering from a chronic deficit in the current account for many decades. Current account deficit strengthens the foreign currency against the home currency which makes imports of good and services more expensive as compared to exports and causes devaluation of home currency. The main objective of this paper is to find out how the current account deficit is influenced by different economic factors. Our regression model’s estimated results indicate that the percentage change in the volume of imports, foreign direct investments and total consumption are positively correlated and, on the other hand, exports, workers remittance, growth in agriculture and manufacturing are negatively correlated with the current account balance of Pakistan during the observed period 1972-2001.

关键词： current account deficit devaluation foreign direct investment total consumption

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