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Enhancing Solar Photovoltaic Efficiency:A Computational Fluid Dynamics Analysis

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Energy Engineering 2025年第1期122卷 153-166页

作者： Rahool rai Fareed HussainMangi Kashif Ahmed Sudhakar Kumaramsay Faculty of Mechanical and Automotive Engineering Universiti Malaysia Pahang Al-Sultan AbdullahPekan26600PahangMalaysia Faculty of Engineering Science&Technology Hamdard UniversityKarachi74600Pakistan Electrical Engineering Department SUKKUR IBA UniversitySukkur65200Pakistan Berlin School of Business and Innovation BSBI Faculty of Computer Science and InformaticsBerlin12043Germany Automotive Engineering Centre University Malaysia Pahang Al Sultan AbdullahPekan26600PahangMalaysia Centre for Research in Advanced Fluid&Processes(Fluid Centre) Universiti Malaysia Pahang Al-Sultan Abdullah(UMPSA)Paya BesarKuantan26300PahangMalaysia

The growing need for sustainable energy solutions,driven by rising energy shortages,environmental concerns,and the depletion of conventional energy sources,has led to a significant focus on renewable *** energy,among the various renewable sources,is particularly appealing due to its abundant ***,the efficiency of commercial solar photovoltaic(PV)modules is hindered by several factors,notably their conversion efficiency,which averages around 19%.This efficiency can further decline to 10%–16%due to temperature increases during peak sunlight *** study investigates the cooling of PV modules by applying water to their front surface through Computational fluid dynamics(CFD).The study aimed to determine the optimal conditions for cooling the PV module by analyzing the interplay between water film thickness,Reynolds number,and their effects on temperature reduction and heat *** CFD analysis revealed that the most effective cooling condition occurred with a 5 mm thick water film and a Reynolds number of *** specific parameters were found to maximize the heat transfer and temperature reduction *** finding is crucial for the development of practical and efficient cooling systems for PV modules,potentially leading to improved performance and longevity of solar *** cooling fluids or advanced cooling techniques that might offer even better efficiency or practical benefits.

关键词： PV module efficiency water film thickness reynolds number CFD analysis PV/T renewable energy

Polyethylene glycol fusion repair of severed sciatic nerves accelerates recovery of nociceptive sensory perceptions in male and female rats of different strains

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Neural Regeneration Research 2025年第9期20卷 2667-2681页

作者： Liwen Zhou Karthik Venkudusamy Emily A.Hibbard Yessenia Montoya Alexa Olivarez Cathy Z.Yang Adelaide Leung varun Gokhale Guhan Periyasamy Zeal Pathak Dale R.Sengelaub George D.Bittner Department of Neuroscience University of TexasAustinTXUSA Program in Neuroscience Indiana UniversityBloomingtonINUSA Department of Molecular Biosciences University of TexasAustinTXUSA

Successful polyethylene glycol fusion(PEG-fusion)of severed axons following peripheral nerve injuries for PEG-fused axons has been reported to:(1)rapidly restore electrophysiological continuity;(2)prevent distal Wallerian Degeneration and maintain their myelin sheaths;(3)promote primarily motor,voluntary behavioral recoveries as assessed by the Sciatic Functional Index;and,(4)rapidly produce correct and incorrect connections in many possible combinations that produce rapid and extensive recovery of functional peripheral nervous system/central nervous system connections and reflex(e.g.,toe twitch)or voluntary *** preceding companion paper describes sensory terminal field reo rganization following PEG-fusion repair of sciatic nerve transections or ablations;howeve r,sensory behavioral recovery has not been explicitly explored following PEG-fusion *** the current study,we confirmed the success of PEG-fusion surgeries according to criteria(1-3)above and more extensively investigated whether PEG-fusion enhanced mechanical nociceptive recovery following sciatic transection in male and female outbred Sprague-Dawley and inbred Lewis *** nociceptive responses were assessed by measuring withdrawal thresholds using von Frey filaments on the dorsal and midplantar regions of the *** von Frey filament tests were a more reliable method than plantar von Frey filament tests to assess mechanical nociceptive sensitivity following sciatic nerve *** withdrawal thresholds of the sciatic-mediated lateral dorsal region differed significantly across strain but not *** thresholds did not change significantly from baseline in chronic Unoperated and Sham-operated *** sciatic transection,all rats exhibited severe hyposensitivity to stimuli at the lateral dorsal region of the hindpaw ipsilateral to the ***,PEG-fused rats exhibited significantly earlier return to baseline withdrawal thresholds than Negative

关键词： autophagia axotomy collateral sprouting neuropathic pain peripheral nerve repair polyethylene glycol fusion(PEG-fusion) saphenous nerve sensory neurons sex and strain Wallerian degeneration

Design and investigation of doping-less gate-all-around TFET with Mg_(2)Si source material for low power and enhanced performance applications

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Chinese Physics B 2023年第10期32卷 615-624页

作者： Pranav Agarwal Sankalp rai Rakshit Y.A varun Mishra Graphic Era(deemed to be university) DehradunUttarakhandIndia

Metal–oxide–semiconductor field-effect transistor(MOSFET)faces the major problem of being unable to achieve a subthreshold swing(SS)below 60 mV/*** device dimensions continue to reduce and the demand for high switching ratios for low power consumption increases,the tunnel field-effect transistor(TFET)appears to be a viable device,displaying promising characteristic as an answer to the shortcomings of the traditional *** far,TFET designing has been a task of sacrificing higher ON state current for low subthreshold swing(and vice versa),and a device that displays both while maintaining structural integrity and operational stability lies in the nascent stages of popular *** work presents a comprehensive analysis of a heterojunction plasma doped gate-all-around TFET(HPD-GAA-TFET)by making a comparison between Mg_(2)Si and Si which serve as source *** plasma technique is employed to implement doping in an intrinsic silicon wafer with the help of suitable electrodes.A low-energy bandgap material,*** silicide is incorporated as source material to form a heterojunction between source and silicon-based channel.A rigorous comparison of performance between Si-based GAA-TFET and HPD-GAA-TFET is conducted in terms of electrical,radio frequency(RF),linearity,and distortion *** is observable that HPD-GAA-TFET outperforms conventional Si-based GAA-TFET with an ON-state current(I_(ON)),subthreshold swing(SS),threshold voltage(V_(th)),and current switching ratio being 0.377 mA,12.660 mV/dec,0.214 V,and 2.985×10^(12),***,HPD-GAA-TFET holds faster switching and is more reliable than Si-based ***,HPD-GAA-TFET is suitable for low-power applications.

关键词： subthreshold Mg_(2)Si heterojunction charge plasma gate-all-around(GAA)

The meridional circulation of the Sun: Observations, theory and connections with the solar dynamo

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Science China(Physics,Mechanics & Astronomy) 2021年第3期64卷 46-72页

作者： Arnab rai Choudhuri Department of Physics Indian Institute of ScienceBangalore560012India

The meridional circulation of the Sun, which is observed to be poleward at the surface, should have a return flow at some depth. Since large-scale flows like the differential rotation and the meridional circulation are driven by turbulent stresses in the convection zone, these flows are expected to remain confined within this zone. Current observational(based on helioseismology)and theoretical(based on dynamo theory) evidences point towards an equatorward return flow of the meridional circulation at the bottom of the convection zone. Assuming the mean values of various quantities averaged over turbulence to be axisymmetric,we study the large-scale flows in solar-like stars on the basis of a 2D mean field theory. Turbulent stresses in a rotating star can transport angular momentum, setting up a differential rotation. The meridional circulation arises from a slight imbalance between two terms which try to drive it in opposite directions: a thermal wind term(arising out of the higher efficiency of convective heat transport in the polar regions) and a centrifugal term(arising out of the differential rotation). To make these terms comparable,the poles of the Sun should be slightly hotter than the equator. We discuss the important role played by the meridional circulation in the flux transport dynamo model. The poloidal field generated by the Babcock-Leighton process at the surface is advected poleward, whereas the toroidal field produced at the bottom of the convection zone is advected equatorward. The fluctuations in the meridional circulation(with coherence time of about 30-40 yr) help in explaining many aspects of the irregularities in the solar cycle. Finally, we discuss how the Lorentz force of the dynamo-generated magnetic field can cause periodic variations in the large-scale flows with the solar cycle.

关键词： astrophysical plasma solar physics Sun:solar magnetism Sun:helioseismology fluid flow:rotational

Characteristics of Emission Non-nulling Pulsars Through Simulation

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Research in Astronomy and Astrophysics 2024年第4期24卷 91-102页

作者： rai Yuen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Xinjiang Key Laboratory of Radio Astrophysics Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China SIfA School of PhysicsUniversity of SydneySydneyNSW2006Australia

We investigate the population and several properties of radio pulsars whose emission does not null(non-nulling)through simulation of a large pulsar *** from a pulsar is identified as non-nulling if(i)the emission does not cease across the whole pulse profile,and(ii)the emission is ***(i),we adopt a model for switching in the plasma charge density,and emission persists if the charge density is ***(ii),we assume that detectable emission originates from source points where it is emitted tangentially to the magnetic field-line and parallel to the *** find that pulsars exhibiting non-nulling emission possess obliquity angles with an average of 42°.5,and almost half the samples maintain a duty cycle between 0.05 and ***,the pulsar population is not fixed but dependent on the obliquity angle,with the population peaking at 20°.In addition,three evolutionary phases are identified in the pulsar population as the obliquity angle evolves,with the majority of samples having an obliquity angle between 20°and 65°.Our results also suggest that emission from a pulsar may evolve between nulling and non-nulling during its lifetime.

关键词： radiation mechanisms:non thermal stars:neutron (stars:)pulsars:general

Starspots, stellar cycles and stellar flares： Lessons from solar dynamo models

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Science China(Physics,Mechanics & Astronomy) 2017年第1期60卷 1-16页

作者： Amab rai Choudhuri Department of Physics Indian Institute of Science Bangalore 560012 India

In this review, we discuss whether the present solar dynamo models can be extrapolated to explain various aspects of stellar activity. We begin with a summary of the following kinds of data for solar-like stars:(i) data pertaining to stellar cycles from Ca H/K emission over many years;(ii) X-ray data indicating hot coronal activity;(iii) starspot data(especially about giant polar spots); and(iv) data pertaining to stellar superflares. Then we describe the current status of solar dynamo modelling—giving an introduction to the flux transport dynamo model, the currently favoured model for the solar cycle. While an extrapolation of this model to solar-like stars can explain some aspects of observational data, some other aspects of the data still remain to be theoretically explained. It is not clear right now whether we need a different kind of dynamo mechanism for stars having giant starspots or producing very strong superflares.

关键词： sunspots solar dynamo solar cycle stellar dynamo, stellar activity

Package Coupling Measurement in Object-Oriented Software

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Journal of Computer Science & Technology 2009年第2期24卷 273-283页

作者： varun Gupta Jitender Kumar Chhabra Department of Computer Engineering National Institute of TechnologyKurukshetra

The grouping of correlated classes into a package helps in better organization of modern object-oriented software. The quality of such packages needs to be measured so as to estimate their utilization. In this paper, new package coupling metrics are proposed, which also take into consideration the hierarchical structure of packages and direction of connections among package elements. The proposed measures have been validated theoretically as well as empirically using 18 packages taken from two open source software systems. The results obtained from this study show strong correlation between package coupling and understandability of the package which suggests that proposed metrics could be further used to represent other external software quality factors.

关键词： package coupling metrics object-oriented software understandability

A Survey of Dynamic Software Metrics

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Journal of Computer Science & Technology 2010年第5期25卷 1016-1029页

作者： Jitender Kumar Chhabra varun Gupta Department of Computer Engineering National Institute of TechnologyKurukshetra-136119India

Software metrics help us to make meaningful estimates for software products and guide us in taking managerial and technical ***,conventional static metrics have been found to be inadequate for modern object-oriented software due to the presence of object-oriented features such as polymorphism,dynamic binding,inheritance and unused *** fact motivates us to focus on dynamic metrics in place of traditional static ***,dynamic metrics are more precise than static metrics as they are able to capture the dynamic behaviour of the software system during *** dynamic metrics are usually obtained from the execution traces of the code or from the executable *** this paper,advantages of dynamic metrics over static metrics are discussed and then a survey of the existing dynamic metrics is carried *** metrics are characterized into different categories such as dynamic coupling metrics, dynamic cohesion *** end of the paper,potential research challenges and opportunities in the field of dynamic metrics are identified.

关键词： metrics object-oriented programming software engineering

A New Design Approach for Nearly Linear Phase Stable IIR Filter using Fractional Derivative

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IEEE/CAA Journal of Automatica Sinica 2020年第2期7卷 527-538页

作者： Nikhil Agrawal Anil Kumar varun Bajaj Department of Electronics and Communication Engineering PDPM Indian Institute of Information TechnologyDesign and Manufacturing JabalpurMadhya Pradesh 482005India

In this paper,a new design method for digital infinite impulse response(IIR)filters with nearly linear-phase response is presented using fractional derivative constraints(FDCs).In the proposed method,design problem of an IIR frlter is constructed as the minimization of phase error between the desired and designed phase response of an allpass filter(APF)such that the designed lowpass filter(LPF)or highpass frlter(HPF)yields less passband(ep),and stopband errors(es)with optimal stopband attenuation(As).In order to have accurate passband(pb)response,FDCs are imposed on appropriate reference frequency,where the optimality of these FDCs are ensured by using a new greedy based sorting *** simulated results reflect the efficiency of the proposed method in term of improved passband response along with better transition ***,small reduction in^is observed within the allowable limit,when compared to noin-fractional design approach,but the designed filter remains immune to wordlength(WL)effect.

关键词： Fractional derivative constraint(FDC) infinite impulse response(IIR)filter least squared linear phase quantization