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Transactions of Nonferrous Metals Society of China 2018年第2期28卷 193-219页

作者： Mohd.Atif WAHID Zahid A.KHAN Arshad Noor SIDDIQUEE Department of Mechanical Engineering Jamia Millia Islamia

Friction stir welding（FSW） is a solid-state welding process which is capable of joining materials which are relatively difficult to be welded by fusion welding process. Further, this process is highly energy-efficient and environmental-friendly as compared to the fusion welding. Despite several advantages of FSW over fusion welding, the thermal cycles involved in FSW cause softening in joints generally in heat-treatable aluminum alloys（AAs） due to the dissolution or coarsening of the strengthening precipitates leading to decrease in mechanical properties. Underwater friction stir welding（UFSW） can be a process of choice to overcome these limitations. This process is suitable for alloys that are sensitive to heating during the welding and is widely used for heat-treatable AAs. The purpose of this article is to provide comprehensive literature review on current status and development of UFSW and its importance in comparison to FSW with an aim to discuss and summarize different aspects of UFSW. Specific attention is given to basic principle including material flow, temperature generation, process parameters, microstructure and mechanical properties. From the review, it is concluded that UFSW is an improved method compared with FSW for improving joint strength. Academicians, researchers and practitioners would be benefitted from this article as it compiles significantly important knowledge pertaining to UFSW.

关键词： aluminum friction stir welding fusion welding mechanical properties microstructure underwater friction stir welding

Stereoselective interactions of chiral dipeptides on amylose based chiral stationary phases

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Science China Chemistry 2015年第3期58卷 519-525页

作者： Imran Ali Ashanul Haque Zeid A.Al-Othman Abdulrahman Al-Warthan Leonid Asnin Department of Chemistry Jamia Millia Islamia Central University Department of Chemistry College of Science King Saud University Perm National Research Polytechnic University

Dipeptides are stereo-specifically involved in several biological functions that are challenging to separate enantiomerically. Elution order of enantiomers is an important issue in chiral chromatography. Amylose tris-(3,5-dimethylphenylcarbamate) chiral stationary phase(CSP) is the best and most-widely-used CSP in chiral separations, but experimental data of enantiomeric separation of dipeptides on this CSP is lacking. Simulation studies were conducted to determine the order of elution and the chiral recognition mechanism of didpetides on this CSP. Results indicated that the docking energy of SR-enantiomers were higher than SS-antipodes. The range of docking energies for SR-enantiomers was -7.44 to -5.92 kcal/mol with CSP, but -7.15 to -5.87 kcal/mol for SS-stereoisomers. Therefore it is predicted that SS-enantiomer will elute first, followed by SR-antipode. Furthermore, hydrogen bondings, van der Waal's interactions and electrostatic interactions were observed among SR- and SSenantiomers and chiral grooves of CSP. The number of hydrogen bonds was one in each enantiomer binding except S-Ala-R-Tyr, which contained two hydrogen bonds. No hydrogen bond was found in S-Ala-R-Trp, S-Leu-S-Trp, and S-Leu-S-Tyr dipeptides bindings. The chiral recognition mechanisms dictate different strengths of stereoselective bindings of the enantiomers on CSP.

关键词： dipeptide enantiomers amylose tris-(3 5-dimethylphenylcarbamate) chiral recognition mechanism elution order Auto Dock 4.2.

Effect of varying spatial orientations on build time requirements for FDM process: A case study

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Defence Technology（防务技术） 2017年第2期13卷 92-100页

作者： Sandeep Rathee Manu Srivastava Sachin Maheshwari Arshad Noor Siddiquee Division of Manufacturing Processes and Automation Engineering Netaji Subhas Institute of Technology Department of Mechanical Engineering Jamia Millia Islamia A Central University

In this research, effect of varying spatial orientations on the build time requirements for fused deposition modelling process is studied. Constructive solid geometry cylindrical primitive is taken as work piece and modeling is accomplished for it. Response surface methodology is used to design the experiments and obtain statistical models for build time requirements corresponding to different orientations of the given primitive in modeller build volume. Contour width, air gap, slice height, raster width, raster angle and angle of orientation are treated as process parameters. Percentage contribution of individual process parameter is found to change for build time corresponding to different spatial orientations. Also, the average of build time requirement changes with spatial orientation. This paper attempts to clearly discuss and describe the observations with an aim to develop a clear understanding of effect of spatial variations on the build time for Fused Deposition Modelling process. This work is an integral part of process layout optimization and these results can effectively aid designers specially while tackling nesting issues.

关键词： Fused deposition modeling Spatial orientation Process parameters Response Surface Methodology Build time

Effect of tool plunge depth on reinforcement particles distribution in surface composite fabrication via friction stir processing

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Defence Technology（防务技术） 2017年第2期13卷 86-91页

作者： Sandeep Rathee Sachin Maheshwari Arshad Noor Siddiquee Manu Srivastava Division of Manufacturing Processes and Automation Engineering(MPAE) Netaji Subhas Institute of Technology Department of Mechanical Engineering Jamia Millia Islamia A Central University

Aluminium matrix surface composites are gaining alluring role especially in aerospace, defence, and marine industries. Friction stir processing(FSP) is a promising novel solid state technique for surface composites fabrication. In this study, AA6061/SiC surface composites were fabricated and the effect of tool plunge depth on pattern of reinforcement particles dispersion in metal matrix was investigated. Six varying tool plunge depths were chosen at constant levels of shoulder diameter and tool tilt angle to observe the exclusive effect of plunge variation. Process parameters chosen for the experimentation are speed of rotation, travel speed and tool tilt angle which were taken as 1400 rpm, 40 mm/min, and 2.5 °respectively. Macro and the microstructural study were performed using stereo zoom and optical microscope respectively. Results reflected that lower plunge depth levels lead to insufficient heat generation and cavity formation towards the stir zone center. On the other hand, higher levels of plunge depth result in ejection of reinforcement particles and even sticking of material to tool shoulder. Thus, an optimal plunge depth is needed in developing defect free surface composites.

关键词： Metal matrix composites Friction stir processing Tool plunge depth Microstructural characterization

AN INEQUALITY FOR POLYNOMIALS WITH A PRESCRIBED ZERO

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Analysis in Theory and Applications 1994年第3期10卷 104-106页

作者： Dewan K.K. Govil N.K. jamia millia islamia India Auburn University. U.S.A.

Let p_n(z)=∑_(k-0)~n a_kz^k be a polynomial of degree n such that |p_n(z)|≤M for |z|≤1. It is well. known that for 0≤u 详细信息

Let p_n(z)=∑_(k-0)~n a_kz^k be a polynomial of degree n such that |p_n(z)|≤M for |z|≤1. It is well. known that for 0≤u

关键词： polynomial inequality Statement precisely

Repurposing of FDA-Approved drugs to predict new inhibitors against key regulatory genes in Mycobacterium tuberculosis

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BIOCELL 2021年第6期45卷 1569-1583页

作者： XINJUN YANG AFTAB ALAM NAIYAR IQBAL KHALID RAZA Department of Pediatrics 3201 HospitalHanzhongChina Centre for Interdisciplinary Research in Basic Sciences Jamia Millia IslamiaNew DelhiIndia Department of Computer Science and Information Technology Maulana Azad National Urdu UniversityHyderabadIndia Department of Computer Science Jamia Millia IslamiaNew DelhiIndia

Tuberculosis(TB)disease has become one of the major public health concerns globally,especially in developing *** research studies have already been carried out for TB,but we are still struggling for a complete and quick cure for *** progress of Mycobacterium tuberculosis(MTB)strains resistant to existing drugs makes its cure and control very ***,it is the need of the hour to search for newer and effective drugs that can inhibit an increasing number of putative drug *** applied the drug repurposing concept to identify promising FDAapproved drugs against five key-regulatory genes(FurB,IdeR,KstR,MosR,and RegX3)of the *** FDA drugs were virtually screened using a structure-based approach by GOLD versions 5.2,and subjected to rigid docking followed by an induced-fit docking algorithm to enhance the accuracy and prioritize drugs for *** found 11 candidate drugs(including ZINC03871613,ZINC03871614,ZINC03871615 as top scorer candidate drugs)that were frequently present within the top 20 GoldScore ranks and showed promising ***,molecular dynamics simulation was performed to monitor the effect of the top scorer drugs on the structural stability of all the five targets,indicating that inhibitors preferentially bind to the active site of the *** work suggests that these known FDA-approved drugs open new application domains in the form of anti-tuberculosis agents.

关键词： Virtual screening Molecular docking MD simulation PPI network

Friction stir welding of aluminum to copper—An overview

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Transactions of Nonferrous Metals Society of China 2017年第10期27卷 2113-2136页

作者： Nidhi SHARMA Zahid A.KHAN Arshad Noor SIDDIQUEE Department of Mechanical Engineering Jamia Millia Islamia New Delhi India

Components made by joining different materials are required in various engineering *** of suchcomponents is a challenging task due to the vast difference in mechanical,thermal and electrical properties of the materials *** stir welding(FSW)is capable of joining dissimilar materials such as aluminum(Al)and copper(Cu)and thereforeresearchers have used this novel process for dissimilar ***,several works pertaining to dissimilar joining,specifically Al?Cu,are available in the literature but they are scattered in different sources,which makes the task of gatheringinformation about dissimilar FSW of Al?Cu *** work has been written with an aim to provide all pertinentinformation related to dissimilar FSW of Al?Cu at one place to ease the problems of *** comprehensively covers andsummarizes the topics such as the effect of tool design and geometry,FSW process parameters,FSW strategies on mechanicalproperties,microstructure and formation of defects during dissimilar FSW of Al?*** addition,it also presents and discussesseveral variants of dissimilar FSW of Al?***,this work not only puts forth major findings of the previous researchers but alsosuggests future recommendations for dissimilar FSW of Al?Cu.

关键词： aluminium copper friction stir welding intermetallic compounds mechanical properties weld nugget zone

Formalising and Detecting Community Structures in Real World Complex Networks

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Journal of Systems Science & Complexity 2021年第1期34卷 180-205页

作者： KUMAR Pawan DOHARE Ravins School of Sciences Indira Gandhi National Open UniversityNew Delhi 110068India Centre for Interdisciplinary Research in Basic Sciences Jamia Millia IslamiaNew Delhi 110025India

Community structure is an integral characteristic of real world networks whichever processes or areas they emerge from. This paper addresses the problem of community structure detection theoretically as well as computationally. The authors introduce a number of concepts such as the neighbourhood and strength of a subgraph, p-community, local maximal p-community, hubs, and outliers that play elemental role in formalising the concept of community structure in complex networks. A few preliminary results have been derived that lead to the development of an algorithm for community structure detection in undirected unweighted networks. The algorithm is based on a local seed expansion strategy that uses the concept of interaction coefficient. The authors have analysed the algorithm on a number of parameters such as accuracy, stability, and quality on synthetic and real world networks from different areas.

关键词： Algorithm hub local maximal p-community outlier p-community strength of a subgraph

Giant magneto resistance and temperature coefficient of resistance in Sm0.55Sr0.30Ag0.15MnO3 perovskite

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Progress in Natural Science:Materials International 2016年第6期26卷 579-583页

作者： Masroor Ahmad Bhat Rayees A.Zargar Anchit Modi Manju Arora N.K.Gaur Superconductivity Research Lab Department of PhysicsBarkatullah University Department of Physics Jamia Millia Islamia CSIR-National Physical Laboratory Dr.K.S.Krishnan Marg

Silver ions substituted samarium strontium manganite(Sm0.55Sr0.30Ag0.15MnO3) pervoskite was synthesized by using respective oxides in stoichiometric ratio through solid state reaction. The as-prepared sample was characterized by various analytical techniques to confirm its formation and understand the effect of monovalent silver ions in pervoskite lattice. X-ray diffraction pattern confirms the single phase formation while grain morphology in SEM image indicates good connectivity among the grains. The enhancement in metal to insulator transition temperature shows quenched disorder and magnetoresistance phenomena. The magnetoresistance（MR） and temperature coefficient of resistance（TCR） emerge from grain growth factor and homogeneity induced by Ag+ions in the lattice. The reduction in hysteresis loss resulted from antiferromagnetic-ferromagnetic（TN） and ferromagnetic- paramagnetic（Tc） transitions reveals the removal of disorder in perovskite lattice by Ag+ions substitution. This increases the magnetic moment across distinct ions on the applying magnetic field. The rise in MR%（99%） with silver doping emerging from smooth spin tunneling of the grains across the boundary and suppression of the disordered magnetic fluctuations with increase in magnetic field has been reported. The present compound exhibits the first order nature of magnetism and observed first time the highest value of TCR ~ 95%.

关键词： Perovskite Transport property Magnetic property TCR Magnetoresistance

A detailed study on trust management techniques for security and privacy in IoT:challenges,trends,and research directions

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High-Confidence Computing 2023年第2期3卷 71-82页

作者： Himani Tyagi Rajendra Kumar Santosh Kr Pandey Department of Computer Science Jamia Millia IslamiaNew Delhi 110025India Department of EC&IT MeityNew Delhi 110003India

The Internet of Things is a modern technology that is directed at easing human life by automating most of the things used in daily *** never-ending dependency on the network for communication is attracting adversaries to exploit the vulnerabilities of ***,this technology is facing some serious issues and challenges concerning security and *** issues and challenges are the real motivation behind considering this ***,this survey includes a discussion about security and privacy challenges as well as available solutions for IoT based wireless sensor *** systematic literature review(SLR)focuses particularly on a popular and applicable security approach known as Trust Management System(TMS).Firstly,all aspects of trust management,including trust indicators,trust properties,trust evaluation,trust building,trust models and the importance of those models for security and privacy,trust prediction methodologies,and ultimately trust-based attacks,are covered in this ***,trust management schemes are classified into four groups based on the methodology used for trust-based security solutions in the IoT:cryptography-based,computational and probabilistic-based,information theory-based,and ***,an understanding of the problems and difficulties with current methodologies is given,along with suggestions for further ***,the SLR is concluded by formulating the desirable characteristics of a trust management system in the IoT and proposing a trust model suitable for IoT networks.

关键词： Trust Trust management approaches IoT Security Privacy Reliability Attacks Trust attributes Systematic literature review Cybersecurity