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Micelle Catalyzed Oxidation of D-Mannose by Cerium (IV) in Sulfuric Acid

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物理化学学报 2008年第5期24卷 810-816页

作者： KABIR-UD-DIN ALI Mohd. sajid KHAN Zaheer Chemistry Department Aligarh Muslim University Aligarh 202002 UP India Chemistry Department Jamia Millia Islamia Jamia Nagar New Delhi 110025 India

Kinetics of D-mannose oxidation by cerium (IV) was studied in a sulfuric acid medium at 40 ℃ both in absence and presence of ionic micelles. In both cases, the rate of the reaction was first-order in D-mannose and in cerium (IV), which decreased with increasing [H2SO4]. This suggested that the redox reaction followed the same mechanism. The reaction proceeded through formation of an intermediate complex, which was proved by kinetic method. The complex underwent slow unimolecular decomposition to a free radical that reacted with cerium (IV) to afford the product. The catalytic role of cationic cetyltrimethylammonium bromide (CTAB) micelles was best explained by the Menger-Portnoy model. The study of the effect of CTAB also indicated that a negatively charged species was reactive form of cerium (IV). From the kinetic data, micelle-cerium (IV) binding and rate constants in micellar medium were evaluated. The anionic micelle of sodium dodecyl sulfate plays no catalytic role. The oxidation has the rate expression: -d[Ce(IV)]= k1Kc1[D-mannose][Ce(IV)]dt Different activation parameters for micelle catalyzed and uncatalyzed paths were also calculated and discussed.

关键词：甘露糖胶束催化剂硫磺酸化学分析

Petrogenesis of Granites from the Utla Area of Gadoon, North-West Pakistan: Implications from Petrography and Geochemistry

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Journal of Earth Science 2014年第3期25卷 445-459页

作者： Muhammad sajid Mohammad Arif M Tahir Shah Department of Geology University of Peshawar National Center of Excellence in Geology University of Peshawar

The granitic rocks around the Utla area（Gadoon）, north western, Pakistan are studied in terms of their petrographic features and geochemical characteristics. Although predominantly mega-porphyritic, some of the Utla granites are massive and display fine-grained equi-granular texture. Some of the mega-porphyritic varieties exhibit foliation and seem to be restricted to shear zones. In addition to being distributed largely as phenocrysts, all the essential minerals（plagioclase, perthitic alkali feldspar and quartz） also constitute the groundmass. The studied samples also contain minor to accessory amounts of tourmaline, muscovite and biotite and accessory to trace amounts of apatite, andalusite, garnet, zircon, monazite, epidote and sphene. A detailed geochemical investigation reveals a calc-alkaline and peraluminous character of the Utla granites. The peraluminous character and total lack of hornblende designate their S-type character while a volcanic arc or syn-collisional tectonic setting for their emplacement is indicated by discrimination diagrams. Further examination shows that the melt parental to the Utla granite was derived from a plagioclase-poor, clay-rich rock, i.e., pelite. The petrogenetically significant petrographic and geochemical features of the Utla granite show greater similarity with the Mansehra than the Ambela granites. These include（i） the predominantly megaporphyritic texture,（ii） the presence of andalusite and tourmaline,（iii） the calc-alkaline geochemical signature and（iv） an indication of similar melt source rock character.

关键词： petrography geochemistry granite Utla Pakistan.

Numerical Study of Mixed Convective Peristaltic Flow through Vertical Tube with Heat Generation for Moderate Reynolds and Wave Numbers

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Communications in Theoretical Physics 2018年第4期69卷 449-460页

作者： Tariq Javed B.Ahmed M.sajid Department of Mathematics and Statistics International Islamic University

The current study focuses on the numerical investigation of the mixed convective peristaltic mechanism through a vertical tube for non-zero Reynolds and wave number. In the set of constitutional equations, energy equation contains the term representing heat generation parameter. The problem is formulated by dropping the assumption of lubrication theory that turns the model mathematically into a system of the nonlinear partial differential equations. The results of the long wavelength in a creeping flow are deduced from the present analysis. Thus, the current study explores the neglected features of peristaltic heat flow in the mixed convective model by considering moderate values of Reynolds and wave numbers. The finite element based on Galerkin's weighted residual scheme is applied to solve the governing equations. The computed solution is presented in the form of contours of streamlines and isothermal lines, velocity and temperature profiles for variation of different involved parameters. The investigation shows that the strength of circulation for stream function increases by increasing the wave number and Reynolds number. Symmetric isotherms are reported for small values of time-mean flow. Linear behavior of pressure is noticed by vanishing inertial forces while the increase in pressure is observed by amplifying the Reynolds number.

关键词： mixed convection peristaltic flow moderate Reynolds number finite element method

Simple, Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel(Ⅱ), Copper (Ⅱ), Cobalt (Ⅱ), and Iron (Ⅲ) with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

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Chemical Research in Chinese Universities 2008年第2期24卷 143-147页

作者： sajid H. Guzar JIN Qin-han Institute of Miniature Analytical Instrumentation College of Chemistry Jilin University Changchun 130021 P. R. China Research Center of Instrumentation Zhejiang University Hangzhou 310058 P. R. China

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.

关键词： Copper(Ⅱ) Nickel(Ⅱ) Cobalt(Ⅱ) Iron(Ⅲ) 2-Pyridine carboxaldehyde isonicotinyl hydrazone(2-PYAINH) Spectrophotometry

Axisymmetric Stagnation-Point Flow with a General Slip Boundary Condition over a Lubricated Surface

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Chinese Physics Letters 2012年第2期29卷 126-129页

作者： M.sajid K.Mahmood Z.Abbas The Abdus Salam International Centre for Theoretical Physics Strada Costiera 1134014TriesteItaly Department of Mathematics Riphah International UniversityIslamabad 44000Pakistan Department of Mathematics The Islamia University of BahawalpurBahawalpurPakistan

We investigate the axisymmetric stagnation-point flow of a viscous fluid over a lubricated surface by imposing a generalized slip condition at the fluid-fluid *** power law non-Newtonian fluid is considered as a *** lubrication layer is thin and assumed to have a variable *** transformed nonlinear ordinary differential equation governing the flow is linearized using *** method of superposi-tion is adopted to convert the boundary value problem into an initial value problem and the solution is obtained numerically by using the fourth-order Runge-Kutta *** results are discussed to see the influence of pertinent *** limiting cases of Navier and no-slip boundary conditions are obtained as the special cases and found to be in excellent agreement with the existing results in the literature.

关键词： boundary ordinary assumed

Nanocarbon-based electrode materials applied for supercapacitors

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Rare Metals 2022年第12期41卷 3957-3975页

作者： Yu-Xiang Yang Kang-Kang Ge sajid ur Rehman Hong Bi School of Chemistry and Chemical Engineering School of Materials Science and EngineeringAnhui UniversityHefei 230601China CIRIMAT UMR CNRS 5085UniversitéPaul Sabatier ToulouseⅢToulouse 31062France CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China

As one of the promising energy storage and conversion systems,supercapacitors(SCs)are highly favored owing to their high power density and good service *** all the key components of supercapacitor devices,the design and investigation of electrode materials play an essential role in determining the whole electrochemical charge storage ***,nanocarbon-based materials(e.g.,graphene,carbon dots,graphene quantum dots,etc.)have been widely used as SC electrode materials because of their good physical structure and chemical properties,providing a new route to further improve the energy density and life span of ***,we review the latest progress of nanocarbon-based materials(including nanocarbon and nanocarbon-based composite materials)as electrode materials in SCs *** recent progress of carbon dots,graphene,carbon nanotubes,and other nanocarbon materials electrodes is summarized,while the capacitance and energy density of the above nanocarbon electrodes still need to be ***,the preparation and performance of nanocarbonbased composite electrodes comprising transition metal oxides,conductive polymer,and metal-organic framework derived porous carbon are ***,we outline major challenges and propose some ideas on building better nanocarbon-based SC electrodes.

关键词： Supercapacitor(SC) Nanocarbon Electrode materials Carbon dots Nanocarbon-based composite

Quantum point defects in 2D materials-the QPOD database

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npj Computational Materials 2022年第1期8卷 532-547页

作者： Fabian Bertoldo sajid Ali Simone Manti Kristian S.Thygesen CAMD Computational Atomic-Scale Materials DesignDepartment of PhysicsTechnical University of Denmark2800Kgs.LyngbyDenmark

Atomically thin two-dimensional(2D)materials are ideal host systems for quantum defects as they offer easier characterisation,manipulation and read-out of defect states as compared to bulk *** we introduce the Quantum Point Defect(QPOD)database with more than 1900 defect systems comprising various charge states of 503 intrinsic point defects(vacancies and antisites)in 82 different 2D semiconductors and *** Atomic Simulation Recipes(ASR)workflow framework was used to perform density functional theory(DFT)calculations of defect formation energies,charge transition levels,Fermi level positions,equilibrium defect and carrier concentrations,transition dipole moments,hyperfine coupling,and zero-field *** states and photoluminescence spectra were calculated for selected high-spin *** this paper we describe the calculations and workflow behind the QPOD database,present an overview of its content,and discuss some general trends and correlations in the *** analyse the degree of defect tolerance as well as intrinsic dopability of the host materials and identify promising defects for quantum technological *** database is freely available and can be browsed via a web-app interlinked with the Computational 2D Materials Database(C2DB).

关键词： database Quantum point

Analysis of the effect of passive measures on the energy consumption and zero-energy prospects of residential buildings in Pakistan

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Building Simulation 2021年第4期14卷 1325-1342页

作者： Muhammad Wasim Anwar Zaib Ali Abdullah Javed Emad Ud Din Muhammad sajid School of Mechanical and Manufacturing Engineering National University of Sciences and TechnologyIslamabadPakistan

Climate change can adversely impact the thermal comfort and energy efficiency of the buildings stock. The South Asian countries are particularly vulnerable to the adverse impacts of climate change specially in the form of rising temperatures and increasing frequency of heat waves. The passive building design measures can be useful in mitigating and adapting to the climate change by increasing energy efficiency and reducing greenhouse gas (GHG) emissions. In this study various passive climate change adaptation measures (PCAMs) have been used individually and in form of combinations in order to analyze their impact on the energy efficacy of residential buildings in Pakistan. It has been found that the natural ventilation and front green wall are the most efficient options for reducing the overall energy consumption. By implementation of these PCAMs, cooling demand can be decreased by 27.75% while heating demand can be reduced by 35%. Secondly, the prospect of net zero-energy building and reduced CO2 emissions are also studied. It has been shown that building can achieve net-zero energy on an annual basis at every orientation and it can attain the status of nearly zero-energy building on a monthly basis. Moreover, emitted CO2 can be reduced by 31% by using the renewable energy.

关键词： building energy simulations net zero-energy passive climate adaptation measures climate change energy consumption Pakistan

Assessing the impact of transmissibility on a cluster-based COVID-19 model in India

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International Journal of Modeling, Simulation, and Scientific Computing 2021年第3期12卷 76-98页

作者： Tanvi Mohammad sajid Rajiv Aggarwal Ashutosh Rajput Department of Mathematics Shaheed Rajguru College of Applied Sciences for Women University of Delhi New Delhi 110096India Mechanical Engineering Department College of Engineering Qassim UniversitySaudi Arabia Department of Mathematics Deshbandhu College University of Delhi New Delhi-110019India Department of Mathematics Faculty of Mathematical Sciences University of DelhiNew Delhi-110007India

In this paper,we have proposed a nonlinear mathematical model of different classes of individuals for coronavirus(COVID-19).The model incorporates the effect of transmission and treatment on the occurrence of new *** the model,the basic reproduction number(R_(0))has been *** to the threshold quantity(R_(0)),the stability of endemic and disease-free equilibrium(DFE)points are *** R_(0)>1,if the endemic equilibrium point exists,then it is locally asymptotically stable,whereas the DFE point is globally asymptotically stable for R_(0)<1 which implies the eradication of the *** effects of various parameters on the spread of COVID-19 are discussed in the segment of sensitivity *** model is numerically simulated to understand the effect of reproduction number on the transmission dynamics of the disease *** the numerical simulations,it is concluded that if the reproduction number for the coronavirus disease is reduced below unity by decreasing the transmission rate and detecting more number of infectives,then the epidemic can be eradicated from the population.

关键词： Mathematical modeling COVID-19 basic reproduction number stabilaity sensitivity index