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Numerical Analysis of Unsteady Magneto-Biphase Williamson Fluid Flow with Time Dependent Magnetic Field

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Communications in Theoretical Physics 2019年第2期71卷 143-151页

作者： Madiha bibi M.Y.Malik A.Zeeshan Department of Mathematics College of Sciences P.O.Box 9004 King Khalid University Department of Mathematics Quaid-I-Azam University Department of Mathematics and Statistics Faculty of Basic and Applied Sciences International Islamic University

Numerical investigation of the dusty Williamson fluid with the dependency of time has been done in current disquisition. The flow of multiphase liquid/particle suspension saturating the medium is caused by stretching of porous surface. The influence of magnetic field and heat generation/absorption is observed. It is assumed that particle has a spherical shape and distributed uniformly in fluid matrix. The unsteady two-dimensional problems are modeled for both fluid and particle phase using conservation of mass, momentum and heat transfer. The finalized model generates the non-dimensioned parameters, namely Weissenberg number, unsteadiness parameter, magnetic parameter,heat generation/absorption parameter, Prandtl number, fluid particle interaction parameter, and mass concentration parameters. The numerical solution is obtained. Locality of skin friction and Nusselt number is deliberately focused to help of tables and graphs. While inferencing the current article it is clearly observed that increment of Williamson parameter, unsteadiness parameter, magnetic parameter, volume fraction parameter, and mass concentration parameter reduces the velocity profile of fluid and solid particles as well. And increment of Prandtl number, unsteadiness parameter,volume fraction parameter, and mass concentration parameter reduces the temperature profile of fluid and solid particles as well.

关键词： unsteady flow multiphase Williamson fluid variable magnetic field permeable wall heat source/sink

Catalyst activation: Surface doping effects of group Ⅵ transition metal dichalcogenides towards hydrogen evolution reaction in acidic media

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Journal of Energy Chemistry 2022年第9期31卷 217-240,I0007页

作者： bibi Ruqi Mrinal Kanti Kabiraz Jong Wook Hong Sang-Il Choi Department of Chemistry and Green-Nano Materials Research Center Kyungpook National UniversityDaegu 41566Republic of Korea Department of Hydrogen&Renewable Energy Kyungpook National UniversityDaegu 41566Republic of Korea Department of Chemistry University of UlsanUlsan 44776Republic of Korea

Two-dimensional(2D) transition metal dichalcogenides(TMDs) have emerged as promising alternatives to the platinum-based catalysts for hydrogen evolution reaction(HER). The edge site of these2D materials exhibits HER-active properties, whereas the large-area basal plane is ***, recent studies and methodologies have been investigated to improve the performance of TMD-based materials by activating inactive sites through elemental doping strategies. In this review,we focus on the metal and non-metal dopant effects on group VI TMDs such as MoS_(2) MoSe_(2) WS_(2)and WSe_(2) for promoting HER performances in acidic electrolytes. A general introduction to the HER is initially provided to explain the parameters in accessing the catalytic performance of dopedTMDs. Then, synthetic methods for doped-TMDs and their HER performances are introduced in order to understand the effect of various dopants including metallic and non-metallic elements. Finally, the current challenges and future opportunities are summarized to provide insights into developing highly active and stable doped-TMD materials and valuable guidelines for engineering TMD-based nanocatalysts for practical water splitting technologies.

关键词： 2D materials Transition metal dichalcogenides Dopant effect Catalytic surface Hydrogen evolution reaction

Chemical constituents and fumigant toxicity of essential oil from Carum copticum against two stored product beetles

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Insect Science 2007年第3期14卷 213-218页

作者： bibi ZAHRA SAHAF SAEID MOHARRAMIPOUR MOHAMMAD HADI MESHKATALSADAT Department of Entomology College of Agriculture Tarbiat Modares University Tehran Department of Chemistry Faculty of Basic Science Lorestan University Khoramabad Iran

Plant secondary metabolites play an important role in plant-insect interactions and therefore such compounds may have insecticidal or antifeedant activity against insects. Carum copticum C. B. Clarke （Apiaceae） is one of these plants that have medicinal effects on humans. The chemical composition of the essential oil from dry seeds of C. copticum was studied by gas chromatography （GC） and gas chromatography mass spectrometry （GC-MS）. Thymol （41.34%）,α-terpinolene （17.46%） and ρ-cymene （11.76%） were found to be the major constituents of the oil. In fumigant toxicity tests with the essential oil against adults of Sitophilus oryzae （L.） and Tribolium castaneum （Herbst） at 27 ±1℃ and 60% ± 5% RH, it was observed that S. oryzae （LC50 = 0.91 μL/L） were significantly susceptible than T. castaneum （LC50 = 33.14 μL/L）. The mortalities of the insect species reached 100% at concentrations higher than 185.2 μL/L and 12-h exposure time. The findings indicate the strong insecticidal activity of C. copticum oil and its potential role as a fumigant for storedproduct insects.

关键词： Carum copticum essential oil fumigant toxicity Sitophilus oryzae Tribolium castaneum

采空区不同岩性破碎岩石压实变形及声发射特征研究

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采矿与安全工程学报 2024年第2期41卷 384-394页

作者：温蓬郭文兵白二虎吴东涛王比比马志宝杨伟强河南理工大学能源科学与工程学院河南焦作454000 西南科技大学环境与资源学院四川绵阳621010 煤炭安全生产与清洁高效利用省部共建协同创新中心河南焦作454000

采空区不同岩性冒落破碎矸石的压实特性及承载力学性质对上覆岩层移动破坏有重要影响。采用侧限压缩试验与声发射测试试验方法,对相同级配的砂岩、砂质泥岩两种单一岩性及砂岩-砂质泥岩组合岩性破碎岩石在侧限压缩条件下的变形特征、破... 详细信息

采空区不同岩性冒落破碎矸石的压实特性及承载力学性质对上覆岩层移动破坏有重要影响。采用侧限压缩试验与声发射测试试验方法,对相同级配的砂岩、砂质泥岩两种单一岩性及砂岩-砂质泥岩组合岩性破碎岩石在侧限压缩条件下的变形特征、破碎特征及不同压缩阶段的声发射特征进行了研究。结果表明:在加载前期,破碎岩石的应变随时间的变化曲线存在直线上升段,随时间增加,呈现急剧上升后趋于平缓的特征;不同单一及组合岩性破碎岩石在侧限受压过程中应力与应变均呈非线性关系;根据破碎岩石的应力-应变特征将破碎岩石的压缩变形过程划分为快速压密阶段、缓慢压实阶段及稳定压固阶段。随着轴向压力逐渐增大,破碎岩样的大颗粒骨架破坏、中等颗粒移位滑动、小颗粒填充孔隙;不同岩性的应变与应力呈正相关关系,孔隙率与应力呈负相关关系,组合岩性岩样介于单一岩性岩样之间;不同单一、组合岩性比例与破碎岩样分形维数呈指数函数关系;基于压实变形声发射测试试验结果将破碎岩石压缩过程划分为滑移流动变形阶段、压裂变形填充阶段及压密弹性变形3个阶段;不同阶段破碎岩样的累计计数及累计能量曲线均表现出阶段性的变化特征,随着应力增加,前期声发射累计振铃计数及累计能量表现出先快速线性增加,后趋于平缓,再上升的趋势,后期增加速率逐渐减小,曲线逐渐趋于平缓;组合岩性岩样的声发射累计计数及能量均介于单一岩性岩样之间。研究结果为采空区上覆岩层及地表移动、采空区安全治理提供有力的理论指导。

关键词：采空区破碎岩石压实特性分形维数声发射监测

Influence of Cu doping in Magnesium Hydroxide Nanoparticles for Bandgap Engineering

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Journal of Wuhan University of Technology(Materials Science) 2023年第3期38卷 485-489页

作者： SYED Masood Raza S NASEEM Shah ADEEL Tahir YASMEEN bibi Department of Physics Federal Urdu University of ArtsScience&TechnologyKarachiPakistan Department of Chemistry Federal Urdu University of ArtsScience&TechnologyKarachiPakistan

Cu doped Mg(OH)_(2) nanoparticles were synthesized with varying concentrations from 0 to 10%by a chemical synthesis technique of coprecipitation.X-rays diffraction (XRD) of the samples confirms that all the samples acquire the hexagonal crystal *** results indicated the solubility limit of dopant in the host material and the secondary phase of CuO was observed beyond 3%Cu doping in Mg(OH)_(2).The reduction in the size of nanoparticles was observed from 166 to 103 nm for Mg(OH)_(2) and 10% Cu doped Mg(OH)_(2)samples,*** shift in absorption spectra exhibited the systematical enhancement in optical bandgap from 5.25 to 6.085 eV.A good correlation was observed between the bandgap energy and crystallite size of the nanocrystals which confirmed the size induced effect in the *** transformation in the sample morphology was observed from irregular spherical particles to sepals like shapes with increasing the Cu concentration in the host *** energy dispersive X-Ray (EDX) analysis confirmed the purity of mass percentage composition of the elements present in the samples.

关键词： Cu doped Mg(OH)_(2) nanoparticles phase purity optical band gap morphologies

Mass Transfer of MHD Nanofluid in Presence of Chemical Reaction on A Permeable Rotating Disk with Convective Boundaries, Using Buongiorno’s Model

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Computer Modeling in Engineering & Sciences 2018年第7期116卷 31-49页

作者： Muhammad Shoaib Arif Yasir Nawaz Mairaj bibi Zafar Ali Department of Mathematics Air UniversityPAF Complex E-9Islamabad44000Pakistan Department of Mathematics Comsats UniversityPark Road Chak Shahzad CampusIslamabad44000Pakistan

This communiquéis opted to study the flow of nanofluid because of heated disk rotation subjected to the convective boundaries with chemical reaction of first *** Buongiorno’s model for nanofluids is used due to its wide range of applications and the rotating disk under investigation is *** magneto Reynolds parameter and boundary layer assumptions are carried out to formulate the *** system of nonlinear partial differential equations governing the flow problem is converted into the set of ordinary differential equations by using particular relations known as Von Karman *** complicated set of coupled ordinary differential equations with complicated boundary conditions is set to solve by an analytical technique Homotopy Analysis Method(HAM).Whereby the results obtained by the aforementioned method are provided analytically and analyzed *** validation of the work is confirmed by providing comparison of previous works in tabular *** of chemical reaction parameter on mass transfer rate is also highlighted tabularly for its *** and Sherwood numbers calculated and compared to the like literature and found in good agreement.

关键词： Chemical reaction rotating disk nanoparticles velocity slip magnetic effect.

Traditional medicines and their in-vitro proof against Staphylococcus aureus in Pakistan

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Asian Pacific Journal of Tropical Medicine 2018年第6期11卷 355-368页

作者： Muhammad Adnan Akash Tariq Roqaia bibi Sakina Mussarat bibi Fatima Nawab Ali Hazir Rahman Zabta Khan Shinwari Department of Botany Kohat University of Science and TechnologyKohat 26000Pakistan Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization&Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province Chengdu Institute of BiologyChinese Academy of SciencesChengdu 610041 University of Chinese Academy of Sciences Beijing 100039China Department of Biotechnology and Genetic Engineering Kohat University of Science and TechnologyKohat 26000Pakistan Department of Microbiology Abdul Wali Khan UniversityMardan 23200Pakistan Department of Biotechnology and Bioinformatics Quaid-i-Azam UniversityIslamabad 45320Pakistan

Objective:To gather the fragmented literature on ethnobotany,phytochemistry and in-vitro activities of medicinal plants of Pakistan being used against common infections caused by Staphylococcus aureus(***).Methods:A large number of published and unpublished research studies related to the ethnomedicinal,phytochemical and *** activity of medicinal flora of Pakistan published from 1990-2018 were reviewed using online bibliographic databases such as PubMed,Web of Science,Science Direct,ResearchGate and ***:*** can cause many human ailments including endocarditis,staphylococcal scalded skin syndrome,septic arthritis,respiratory problems with an estimated infection rate of 25%-35%across the *** review comprised of 86 medicinal *** showed that people mostly used leaves(50%)for the preparation of traditional *** analysis on the reviewed data revealed that methanolic extract concentrations of medicinal plants was highly significantly positive correlated(r=0.8;P<0.01)with the *** zone of *** reportedly showed complete resistant to the commonly used antibiotic *** compounds like altheahexacosanyl lactone,cinnamaldehyde,niloticane,gobicusin A,asparacosin A,muzanzagenin,isoagatharesinol,friedelin,inophynone and eugenol were active against *** study provided in-vitro proof for the flora of Pakistan used against different infections caused by ***:Antibacterial agents from natural sources could be more effective against bacterial pathogens and will be helpful in minimizing the adverse effects of synthetic drugs,and hence provides a base for the pharmaceutical industries.

关键词： Gram positive bacteria Herbal medicines Plant extracts Phytochemicals In-vitro

Effect of Cu/Zn Substitution in MgO Nanostructures for Tuning the Optical Bandgap and Structural Properties

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Journal of Wuhan University of Technology(Materials Science) 2022年第6期37卷 1035-1040页

作者： ATIF Dawar S NASEEM Shah M ASIF Siddiqui YASMEEN bibi Department of Physics Federal Urdu University of ArtsScience and TechnologyKarachiPakistan Department of Chemistry Federal Urdu University of ArtsScience and TechnologyKarachiPakistan

Low cost co-precipitation method was used to synthesize Cu(0-0.05)doped MgO samples with fixed concertation of Zn=0.01.X-ray diffraction(XRD)spectra confirmed the phase purity of the samples for 0≤Cu≤0.03 doping *** secondary phase for 0.04≤Cu≤0.05 exhibited the formation of mixed metal *** crystallite size was found to increase from 17.5 to 23.5 nm for 0≤Cu≤0.03 and then decreased from 22 to 18.5 nm for 0.04≤Cu≤*** estimated bandgap first reduced from 5.48 to 4.88 eV and then increased from 5.21 to 5.36 *** morphology of the samples transformed from spheroidal shape to star-like *** obtained results reveal that the structural and optical property are in good agreement with the morphological *** peak shifting towards the lower values of vibrational frequency from 694 to 579 cm^(-1) confirms the incorporation of Cu/Zn in Mg-O *** tuning of optical bandgap and structural properties with varying dopant concentration in MgO nanomaterials can be used for multifunctional modern energy storage and optoelectronic devices.

关键词： Cu/Zn doping MgO optical bandgap morphology vibrational modes

Hot corrosion of surface-modified Sm_(2)Co_(17) high-temperature magnet with Ni and Ni/Cr bilayer coatings in 75 wt% Na_(2)SO_(4)–NaCl mixture

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Rare Metals 2021年第9期40卷 2494-2500页

作者： Saira bibi Jing-Min Wang Tariq Mehmood Waheed Qamar Khan Cheng-Bao Jiang Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing 100191China Institute of Advanced Materials Bahauddin Zakariya UniversityMultan 60800Pakistan School of Space and Environment Beihang UniversityBeijing 100191China

Hot corrosion behavior of Sm_(2)(Co, Fe, Cu,Zr)17-type high-temperature magnetic alloy without and with a protective coating of Ni and Ni/Cr bilayer at 500 ℃ in a corrosive mixture of 75 wt% Na_(2)SO_(4)–NaCl for 100 h was reported in this paper. The obtained results of timedependent weight change established the parabolic growth of oxidized surface of bare magnets(8.87 mg·cm^(-2)),which caused a rapid loss of magnetic properties measured both at room and high temperatures(500 ℃). X-ray diffraction(XRD) analysis revealed the growth of oxides for bare magnet and Cr–oxides(Cr_(2) O_(3)), top layer of Ni/Cr bilayer coating, but in the case of single coating, Ni–sulfides formation indicated penetration of sulfur, which is further verified by electron probe microanalysis with energy dispersive spectroscopy(EPMA/EDS) *** showed that bilayer-coated samples(Ni/Cr) performed better than Ni-coated and bare samples.

关键词： Hot corrosion SmCo-based alloys Oxidation Coatings