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Survey and technological analysis of laser and its defense applications

Defence Technology（防务技术） 2021年第2期17卷 583-592页

作者： syed Affan Ahmed Mujahid Mohsin syed Muhammad Zubair Ali Department of Avionics Engineering-College of Aeronautical Engineering(CAE) National University of Sciences and Technology(NUST)RisalpurKPKPakistan

The laser technology has made remarkable progress over the past couple of *** is being widely employed in diverse domains,such as holography,space sciences,spectroscopy,medical sciences,micro and power electronics,industrial engineering,and most distinctively,as directed energy military *** to their active transmissions,laser systems are similar to microwave radars to some extent;however,unlike conventional radars,the laser operates at very high frequencies thus making it a potent enabler of narrow-beam and high energy aerial deployments,both in offensive and defensive *** modern avionics systems,laser target indicators and beam riders are the most common devices that are used to direct the Laser Guided Weapons(LGW)accurately to the ground ***,compact size and outstanding angular resolution of laser-based systems motivate their use for drones and unmanned aerial ***,the narrow-beam divergence of laser emissions offers a low probability of intercept,making it a suitable contender for secure transmissions and safety-critical ***,the developments in space sciences and laser technology have given synergistic potential outcomes to use laser systems in space *** paper comprehensively reviews laser applications and projects for strategic defense actions on the ground or in ***,a detailed analysis has been done on recent advancements of the laser technology for target indicators and *** also reviews the advancements in the field of laser communications for surveillance,its earlier state of the art,and ongoing scientific research and advancements in the domain of high energy directed laser weapons that have revolutionized the evolving military *** offering a comprehensive taxonomy,the paper also critically analyzes some of the recent contributions in the associated domains.

关键词： Laser systems Laser military applications Directed energy weapons Non-lethal weapons Laser military projects Survey Taxonomy

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Slender reinforced concrete shear walls with high-strength concrete boundary elements

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Frontiers of Structural and Civil Engineering 2023年第1期17卷 138-151页

作者： Mohammad syed Pinar OKUMUS Department of Civil Structural and Environmental EngineeringUniversity at BuffaloBuffaloNY 14260USA

Reinforced concrete structural walls are commonly used for resisting lateral forces in buildings. Owing to the advancements in the field of concrete materials over the past few decades, concrete mixes of high compressive strength, commonly referred to as high-strength concrete (HSC), have been developed. In this study, the effects of strategic placement of HSC on the performance of slender walls were examined. The finite-element model of a conventional normal-strength concrete (NSC) prototype wall was validated using test data available in extant studies. HSC was incorporated in the boundary elements of the wall to compare its performance with that of the conventional wall at different axial loads. Potential reductions in the reinforcement area and size of the boundary elements were investigated. The HSC wall exhibited improved strength and stiffness, and thereby, allowed reduction in the longitudinal reinforcement area and size of the boundary elements for the same strength of the conventional wall. Cold joints resulting from dissimilar concrete pours in the web and boundary elements of the HSC wall were modeled and their impact on behavior of the wall was examined.

关键词： slender walls high-strength concrete rectangular and barbell-shaped walls cold joints

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Robust stability analysis of Takagi-Sugeno uncertain stochastic fuzzy recurrent neural networks with mixed time-varying delays

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Chinese Physics B 2011年第8期20卷 1-15页

作者： M.syed Ali Department of Mathematics Thiruvalluvar UniversityVellore-632 106TamilnaduIndia

In this paper, the global stability of Takagi-Sugeno （TS） uncertain stochastic fuzzy recurrent neural networks with discrete and distributed time-varying delays （TSUSFRNNs） is considered. A novel LMI-based stability criterion is obtained by using Lyapunov functional theory to guarantee the asymptotic stability of TSUSFRNNs. The proposed stability conditions are demonstrated through numerical examples. Furthermore, the supplementary requirement that the time derivative of time-varying delays must be smaller than one is removed. Comparison results are demonstrated to show that the proposed method is more able to guarantee the widest stability region than the other methods available in the existing literature.

关键词： recurrent neural networks linear matrix inequality Lyapunov stability time-varyingdelays TS fuzzy model

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Novel delay-dependent stability analysis of Takagi-Sugeno fuzzy uncertain neural networks with time varying delays

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Chinese Physics B 2012年第7期21卷 49-60页

作者： M. syed Ali Department of Mathematics Thiruvalluvar University

This paper presents the stability analysis for a class of neural networks with time varying delays that are represented by the Takagi^ugeno IT-S） model. The main results given here focus on the stability criteria using a new Lyapunov functional. New relaxed conditions and new linear matrix inequality-based designs are proposed that outperform the previous results found in the literature. Numerical examples are provided to show that the achieved conditions are less conservative than the existing ones in the literature.

关键词： neutral neural networks linear matrix inequality Lyapunov stability time varying delays

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Stability analysis of Markovian jumping stochastic Cohen Grossberg neural networks with discrete and distributed time varying delays

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Chinese Physics B 2014年第6期23卷 131-137页

作者： M.syed Ali Department of Mathematics Thiruvalluvar University

In this paper, the global asymptotic stability problem of Markovian jumping stochastic Cohen-Grossberg neural networks with discrete and distributed time-varying delays （MJSCGNNs） is considered. A novel LMI-based stability criterion is obtained by constructing a new Lyapunov functional to guarantee the asymptotic stability of MJSCGNNs. Our results can be easily verified and they are also less restrictive than previously known criteria and can be applied to Cohen-Grossberg neural networks, recurrent neural networks, and cellular neural networks. Finally, the proposed stability conditions are demonstrated with numerical examples.

关键词： Cohen-Grossberg neural networks global asymptotic stability linear matrix inequality Lyapunovfunctional time-varying delays

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COMPARISON OF TWO METHODS TO INCREASE TIP CLEARANCE AND ITS EFFECT ON PERFORMANCE OF TURBOCHARGER CENTRIFUGAL COMPRESSOR STAGE

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Chinese Journal of Mechanical Engineering 2007年第4期20卷 60-65页

作者： syed Noman Danish School of Mechanical and Vehicular Engineering Beijing Institute of TechnologyBeijing 100081China

Tip clearance between the blade tip and casing of a centrifugal compressor can be varied through two methods： by changing the blade height （MI） or by changing the casing diameter （M2）. Numerical simulations are carried out to compare these two methods and their effect on the stage and impeller performance. The impeller and diffuser are connected through rotor stator boundary using frozen rotor approach. Overall stage performance and the flow configuration have been investigated for nine tip clearance levels from no gap to 1 mm. Impeller and diffuser performances are also presented separately. It has been found that the overall and impeller performance are comparatively better for MI below tip clearance of 0.5 mm whereas M2 is found advantageous above 0.5 mm of tip clearance. Both MI and M2 show performance degradation with the increase in tip clearance. Two models have been proposed for the stage total pressure ratio and efficiency, which are found to be in agreement with experimental results. The impeller efficiency and the pressure ratio are found to be maximum at tip clearance of 0.1 mm for both the cases however minimum diffuser effectiveness is also observed at the same clearance level. Diffuser effectiveness is found to be maximum at zero gap for both cases. As it is practically impossible to have zero gap for unshrouded impellers so it is concluded that the optimum thickness is 0.5 mm onwards for MI and 0.5 mm for M2 in terms of diffuser effectiveness. Mass averaged flow parameters, entropy, blade loading diagram and relative pressure fields are presented, showing the loss production within the impeller passage with tip clearance.

关键词： Centrifugal impeller Diffuser Stage Tip clearance Numerical simulation Entropy

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Molecular hallmarks of long non-coding RNAs in aging and its significant effect on aging-associated diseases

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Neural Regeneration Research 2023年第5期18卷 959-968页

作者： syed Aoun Mehmood Sherazi Asim Abbasi Abdullah Jamil Mohammad Uzair Ayesha Ikram Shanzay Qamar Adediji Ayomide Olamide Muhammad Arshad Peter J.Fried Milos Ljubisavljevic Ran Wang shahid Bashir Department of Biological Sciences Faculty of Basic&Applied SciencesInternational Islamic UniversityIslamabadPakistan Department of Biological Sciences University of ArkansasFayettevilleARUSA Department of Pharmacology Government College UniversityFaisalabadPakistan Department of Bioinformatics and Biotechnology Government College UniversityFaisalabadPakistan Department of Chemistry Chulalongkorn UniversityThailand Department of Neurology Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive NeurologyBeth Israel Deaconess Medical Center(KS 158)Harvard Medical SchoolBostonMAUSA Department of Physiology College of Medicine and Health SciencesUnited Arab Emirates UniversityAl AinUnited Arab Emirates Department of Psychiatry The First Hospital of Hebei Medical UniversityShijiazhuangHebei ProvinceChina Mental Health Institute of Hebei Medical University ShijiazhuangHebei ProvinceChina Neuroscience Center King Fahad Specialist HospitalDammamSaudi Arabia

Aging is linked to the deterioration of many physical and cognitive abilities and is the leading risk factor for Alzheimer’s disease. The growing aging population is a significant healthcare problem globally that researchers must investigate to better understand the underlying aging processes. Advances in microarrays and sequencing techniques have resulted in deeper analyses of diverse essential genomes(e.g., mouse, human, and rat) and their corresponding cell types, their organ-specific transcriptomes, and the tissue involved in aging. Traditional gene controllers such as DNA-and RNA-binding proteins significantly influence such programs, causing the need to sort out long non-coding RNAs, a new class of powerful gene regulatory elements. However, their functional significance in the aging process and senescence has yet to be investigated and identified. Several recent researchers have associated the initiation and development of senescence and aging in mammals with several well-reported and novel long non-coding RNAs. In this review article, we identified and analyzed the evolving functions of long non-coding RNAs in cellular processes, including cellular senescence, aging, and age-related pathogenesis, which are the major hallmarks of long non-coding RNAs in aging.

关键词： aging Alzheimer’s disease DNA sequence epigenetics immune non-coding RNA oligonucleotides telomere-associated

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Prediction of pressure gradient and hold-up in horizontal liquid-liquid pipe flow

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Petroleum Science 2023年第6期20卷 3766-3782页

作者： syed Amjad Ahmed Bibin John School of Mechanical Engineering Vellore Institute of TechnologyIndia Department of Mechanical Engineering C Abdul Hakeem College of Engineering&TechnologyIndia

This paper aims to propose correlations to predict pressure gradient,friction factor and fluid phase hold-up in liquid-liquid horizontal pipe *** develop the correlations,experiments are conducted using high viscous oils(202 and 630 mPa⋅s)in a steel pipe of length 11.25 m and length-to-diameter ratio of *** addition,the experimental data from the literature comprising wide range of flow and fluid properties is *** the analysis,the liquid-liquid pipe flow data is categorized into two as:stratified and *** existing friction factor correlations are modified to incorporate the effects of viscosity of the oil phase,interfacial curvature(contact/wetting angle-in lieu of material of the pipe)and fluid phase *** the two-fluid model of stratified flow,the wall stress and interfacial stress correlations are substituted with superficial velocities of fluids and superficial Reynolds numbers of fluid phases replacing fluid phase velocities and fluid Reynolds ***,for dispersed flow,an effective Reynolds number is described as the sum of superficial Reynolds number of oil and water *** the generally employed mean or mixture Reynolds number with the effective Reynolds number into the existing single-phase turbulent flow friction factor correlation,an effective friction factor for oil-water flow is *** the proposed correlations,the pressure gradient across the oil-water flow and hold-up volume fraction are predicted with significant reduction in error compared with that of conventionally employed *** average error and standard deviation values of−7.06%,20.72%and 0.31%,18.79%are found for stratified flow and dispersed flow respectively.

关键词： oil-water flow two-fluid model pressure gradient stratified flow dispersed flow

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Robust H_∞ control for uncertain Markovian jump systems with mixed delays

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Chinese Physics B 2016年第7期25卷 108-113页

作者： R Saravanakumar M syed Ali Department of Mathematics Thiruvalluvar University

We scrutinize the problem of robust H∞control for a class of Markovian jump uncertain systems with interval timevarying and distributed delays. The Markovian jumping parameters are modeled as a continuous-time finite-state Markov chain. The main aim is to design a delay-dependent robust H∞control synthesis which ensures the mean-square asymptotic stability of the equilibrium point. By constructing a suitable Lyapunov–Krasovskii functional（LKF）, sufficient conditions for delay-dependent robust H∞control criteria are obtained in terms of linear matrix inequalities（LMIs）. The advantage of the proposed method is illustrated by numerical examples. The results are also compared with the existing results to show the less conservativeness.

关键词： linear matrix inequality Lyapunov method Markovian jumping parameters robust H∞ control

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MECHANICALLY AND THERMALLY STABLE BLENDS OF POLY(STYRENE-BUTADIENE-STYRENE) WITH CONDUCTING POLY(THIOUREA-AZO-NAPHTHYL)

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Chinese Journal of Polymer Science 2013年第12期31卷 1623-1631页

作者： Ayesha Kausar syed Tajammul Hussain Nanosciences and Catalysis Division National Centre for PhysicsQuaid-i-Azam University Campus

A new aromatic azo-polymer, poly（thiourea-azo-naphthyl）（PTAN）, has been synthesized using 1-（5- thiocarbamoylaminonaphthyl）thiourea and diazonium salt solution of 2,6-diaminopyridine. PTAN was easily processable using polar solvents and had high molar mass 57 × 10^3 g/mol. Electrically conducting, mechanically and thermally stable rubbery blends of poly（styrene-butadiene-styrene）（SBS） triblock copolymer and PTAN were produced by solution blending technique. FESEM of SBS/PTAN blends revealed nano-scale dispersion of the conducting filler showing good adhesion between the matrix and PTAN. Remarkable effects of azo-content on the conductivity of SBS-based blends have been observed. Accordingly, PTAN loading from 10 to 60 wt% increased the conductivity from 1.24 to 1.66 S/cm. Relationship between PTAN loading and thermal stability of the materials was also investigated. With increasing the PTAN content, 10% gravimetric loss was increased from 484 to 500 ℃, while glass transition was enhanced from 119 to 126 ℃. Thermal and conducting data of the blend showed better results relative to pure elastomer but were lower than those of the conducting filler. Similarly, the tensile strength （57.35-62.33 MPa） of SBS/PTAN was improved relative to there of SBS. Fine balance of properties renders new materials fairly better than the existing elastomeric blends used in a number of applications.

关键词： Poly(thiourea-azo-naphthyl) SBS Electrical conduction Thermal stability Tensile strength.

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