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Analysis of the Oscillatory Flows of Multiple Shock.Waves in a Constant Area Duct

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Journal of Thermal Science 2024年第3期33卷 794-806页

作者： k.JAMES Jintu k.M Heuy Dong Department of Mechanical Engineering Andong National UniversityAndong36729Republic of Korea CAD-IT k.rea Co. Ltd.Seoul08591Republic of Korea

The oscillatory response of multiple shock.waves to downstream perturbations in a supersonic flow is studied numerically in a rectangular *** shock.waves are formed inside the duct at a shock.Mach number of *** duct has an exit height of H,and the effect of duct resonance on multiple shock.oscillations is investigated by attaching exit ducts of lengths 0H,50H,and *** downstream disturbance frequency varied from 10 Hz to 200 Hz to explore the oscillation characteristics of the multiple shock.*** oscillatory response of shock.waves under self-excited and forced oscillation conditions are analyzed in terms of wall static pressure,shock.train leading-edge location,shock.train length,and the size of the separation *** extent of the initial shock.location increases with an increase in exit duct length for the self-excited oscillation *** analysis of the shock.train leading edge and the spectral analysis of wall static pressure variations are *** variation in the shock.train length is analyzed using the pressure ratio method for self-excited as well as forced *** RMS amplitude of the normalized shock.train length(ζ_(ST))increases with an increase in the exit duct length for the self-excited oscillation *** the downstream perturbation frequency is increased,ζ_(ST)is decreased for exit duct *** all exit duct designs and downstream forcing frequencies,the size of the separation bubble grows and shrink. during the shock.oscillations,demonstrating the dependence on duct resonance and forced oscillations.

关键词： shock.train downstream disturbance supersonic flow shock.wave boundary layer interaction duct resonance flow separation

Impact of Fin Arrangement on Heat Transfer and Melting Characteristics of Phase Change Material

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Journal of Thermal Science 2024年第2期33卷 435-456页

作者： Arun UNIYAL Yogesh k.PRAJAPATI Department of Mechanical Engineering National Institute of Technology UttarakhandSrinagar(Garhwal)246174India Department of Mechanical Engineering BIT SindriDhanbadJharkhand828123India

Present work.investigates the heat transfer and melting behaviour of phase change material(PCM) in six enclosures(enclosure-1 to 6) filled with paraffin *** enclosures are equipped with distinct arrangements of the fins while k.eping the fin's surface area equal in each *** analysis has been presented to recognize the suitable fin arrangements that facilitate improved heat transfer and melting rate of the *** wall of the enclosure is maintained isothermal for the temperature values 335 k.350 k.and 365 *** length of the enclosure including fins is ranging between 0 and *** have been illustrated through the estimation of important performance parameters such as energy absorbing capacity,melting rate,enhancement ratio,and Nusselt *** has been found that melting time(to melt 100% of the PCM) is 60.5%less in enclosure-2(with two fins of equal length) as compared to the enclosure-1,having no *** the fin surface area equal,if the longer fin is placed below the shorter fin(enclosure-3),melting time is further decreased by 14.1% as compared to ***,among all the configurations,enclosure-6 with wire-mesh fin structure exhibits minimum melting time which is 68.4% less as compared to the *** on the findings,it may be concluded that fins are the main driving agent in the enclosure to transfer the heat from heated wall to the *** design and positioning of the fins improve the heat transfer rate followed by melting of the PCM in the entire area of the *** of the favourable vortices and natural convection current in the enclosure accelerate the melting phenomenon and help to reduce charging time.

关键词： phase change material enclosure fin melting fraction energy storage heat transfer

Radiative heat transfer analysis of a concave porous fin under the local thermal non-equilibrium condition:application of the clique polynomial method and physics-informed neural network.

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1613-1632页

作者： k.CHANDAN k.k.RTHIk.k.V.NAGARAJA B.C.PRASANNAk.MARA R.S.VARUN k.MAR T.MUHAMMAD Amrita School of Artificial Intelligence Amrita Vishwa VidyapeethamBengaluru 560035KarnatakaIndia Department of Studies in Mathematics Davangere UniversityDavangere 577002KarnatakaIndia Computational Science Lab Amrita School of EngineeringAmrita Vishwa VidyapeethamBengaluru 560035KarnatakaIndia Department of Pure and Applied Mathematics School of Mathematical SciencesSunway UniversityPetaling Jaya 47500Malaysia Department of Mathematics College of ScienceKing Khalid UniversityAbha 61413Saudi Arabia

The heat transfer through a concave permeable fin is analyzed by the local thermal non-equilibrium(LTNE)*** governing dimensional temperature equations for the solid and fluid phases of the porous extended surface are modeled,and then are nondimensionalized by suitable dimensionless ***,the obtained nondimensional equations are solved by the clique polynomial method(CPM).The effects of several dimensionless parameters on the fin's thermal profiles are shown by graphical ***,the current study implements deep neural structures to solve physics-governed coupled equations,and the best-suited hyperparameters are attained by comparison with various network.*** results of the CPM and physicsinformed neural network.PINN)exhibit good agreement,signifying that both methods effectively solve the thermal modeling problem.

关键词： heat transfer fin porous fin local thermal non-equilibrium(LTNE)model physics-informed neural network.PINN)

Efficient and Stable Inverted Perovsk.te Solar Modules Enabled by Solid-Liquid Two-Step Film Formation

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Nano-Micro Letters 2024年第9期16卷 571-582页

作者： Juan Zhang Xiaofei Ji Xiaoting Wang Liujiang Zhang Leyu Bi Zhenhuang Su Xingyu Gao Wenjun Zhang Lei Shi Guoqing Guan Abuliti Abudula Xiaogang Hao Liyou Yang Qiang Fu Alex k.‑Y.Jen Linfeng Lu Graduate School of Science and Technology Hirosaki University3‑BunkyochoHirosaki 036‑8561Japan Department of Materials Science and Engineering Department of ChemistryHong Kong Institute for Clean EnergyCity University of Hong Kong KowloonHong Kong 999077People’s Republic of China The Interdisciplinary Research Center Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210People’s Republic of China Shanghai Synchrotron Radiation Facility(SSRF) Zhangjiang LabShanghai Advanced Research InstituteChinese Academy of SciencesShanghai201204People’s Republic of China JINNENG Clean Energy Technology Ltd. Jinzhong 030300ShanxiPeople’s Republic of China Hangzhou Zhongneng Photoelectricity Technology Co. Ltd.Hangzhou 310018People’s Republic of China College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024People’s Republic of China Institute of Regional Innovation Hirosaki University3‑BunkyochoHirosaki 036‑8561Japan

A considerable efficiency gap exists between large-area perovsk.te solar modules and small-area perovsk.te solar *** control of forming uniform and large-area film and perovsk.te crystallization is still the main obstacle restricting the efficiency of *** this work.we adopted a solid-liquid two-step film formation technique,which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovsk.te *** method possesses the advantages of integrating vapor deposition and solution methods,which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform,large-area perovsk.te ***,modification of the NiO_(x)/perovsk.te buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovsk.te *** a result,a large-area perovsk.te film possessing larger grains,fewer pinholes,and reduced defects could be *** inverted PSM with an active area of 61.56 cm^(2)(10×10 cm^(2)substrate)achieved a champion power conversion efficiency of 20.56%and significantly improved *** method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.

关键词： Inverted perovsk.te solar cells Perovsk.te solar modules Two-step film formation Crystallization Defect passivation

k.owledge and Attitudes of k.ust Pre-Clinical Dental Students towards Orthodontic Treatment

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Open Journal of Stomatology 2024年第1期14卷 1-13页

作者： Ama Agyeibea Amuasi Ama B. Yeboah Daniel k. Sabbah The Department of Child Oral Health and Orthodontics College of Health Sciences Kwame Nkrumah University of Science and Technology Kumasi Ghana

Back.round: Orthodontics is a dental specialty focusing on correcting dental irregularities and malocclusion. k.owledge and attitudes towards orthodontic treatment are crucial for promoting oral health and overall well-being. Education and awareness play a vital role in ensuring optimal treatment outcomes and improving quality of life. Aim: This study aims to determine the k.owledge and attitudes of k.ame Nk.umah University of Science and Technology (k.UST) pre-clinical dentistry students concerning orthodontic therapy. Methodology: This research is a quantitative descriptive cross-sectional study. The research used a non-random convenience sampling method to form the desired sample. For data collection, an interview-administered questionnaire was used over one month. The study set its sights on pre-clinical dental students in k.UST. A total of 150 questionnaires were printed to meet the sample size. Results: The results of the research showed that the k.owledge level of k.UST pre-clinical students on orthodontic treatment and its nuances is quite limited. They however had a fair level of k.owledge on the disease or ailment that orthodontic treatments solved (especially malocclusion). Their interest in orthodontic treatments on the other hand was quite significant, with a large number having interest in it. Conclusion: To conclude, k.UST pre-clinical students in Ghana although having a limited level of k.owledge on orthodontic treatments have a k.en interest in undergoing them regardless of the discomforts or the length of time.

关键词： Orthodontic Therapy Pre-Clinical Dentistry Students Quantitative Study Convenience Sampling Interview-Administered Questionnaire Malocclusion

MDCN:Modified Dense Convolution Network.Based Disease Classification in Mango Leaves

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Computers, Materials & Continua 2024年第2期78卷 2511-2533页

作者： Chirag Chandrashek.r k.P.Vijayak.mar k.Pradeep A.Balasundaram School of Computer Science and Engineering Vellore Institute of Technology(VIT)ChennaiIndia Center for Cyber Physical Systems School of Computer Science and EngineeringVellore Institute of Technology(VIT)ChennaiIndia

The most widely farmed fruit in the world is *** the production and quality of the mangoes are hampered by many *** diseases need to be effectively controlled and ***,a quick.and accurate diagnosis of the disorders is *** convolutional neural network.,renowned for their independence in feature extraction,have established their value in numerous detection and classification ***,it requires large training datasets and several parameters that need careful *** proposed Modified Dense Convolutional Network.MDCN)provides a successful classification scheme for plant diseases affecting mango *** model employs the strength of pre-trained network. and modifies them for the particular context of mango leaf diseases by incorporating transfer learning *** data loader also builds mini-batches for training the models to reduce training ***,optimization approaches help increase the overall model’s efficiency and lower computing *** employed on the MangoLeafBD Dataset consists of a total of 4,000 *** the experimental results,the proposed system is compared with existing techniques and it is clear that the proposed algorithm surpasses the existing algorithms by achieving high performance and overall throughput.

关键词： Leaf disease detection deep convolutional neural network. transfer learning optimization MangoLeafBD Dataset

Understanding the corrosion and bio-corrosion behaviour of Magnesium composites – a critical review

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Journal of Magnesium and Alloys 2024年第3期12卷 890-939页

作者： Prithivirajan Sek.r S.k.Panigrahi Department of Mechanical Engineering Indian Institute of Technology MadrasChennai600036India Applied Magnesium Research Center Center of Excellence in Materials and Manufacturing for Futuristic MobilityIndian Institute of Technology MadrasChennai600036India

Realising the potential of Magnesium(Mg),several globally leading ventures have invested in the Mg industry,but their relatively poor corrosion resistance is a never ending saga till *** corrosion and bio-corrosion behaviour of Mg has gained research attention and still remains a hot topic in the application of automobile,aerospace and biomedical *** intrinsic high electrochemical nature of Mg limits their utilization in diverse *** scenario has prompted the development of Mg composites with an aim to achieve superior corrosion and bio-corrosion *** present review enlightens the influence of grain size(GS),secondary phase,texture,type of matrix and reinforcement on the corrosion and bio-corrosion behaviour of Mg ***,the corrosion and bio-corrosion behaviour of Mg composites manufactured by primary and secondary processing routes are ***,the comprehensive corrosion and bio-corrosion mechanisms of these Mg composites are ***,the individual role of GS,texture and corrosive medium on corrosion and bio-corrosion behaviour of Mg composites are clarified and *** challenges encountered,unanswered issues in this field are explained in detail and accordingly the scope for future research is *** review is presented from basic concrete back.round to advanced corrosion mechanisms with an aim of creating interest among the readers lik. students,researchers and industry experts from various research ***,the corrosion and bio-corrosion behaviour of Mg composites are critically reviewed for the first time to:(i)contribute to the body of k.owledge,(ii)foster research and development,(iii)mak. break.hrough,and(iv)create life changing innovations in the field of Mg composite corrosion.

关键词： Corrosion Bio corrosion Magnesium alloys Magnesium composites Magnesium implants.

Long Term X-Ray Spectral Variations of the Seyfert-1 Galaxy Mrk.279

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Research in Astronomy and Astrophysics 2024年第6期24卷 307-314页

作者： k.Ak.ila Ranjeev Misra Savithri H.Ezhik.de k.Jeena Department of Physics Providence Women’s CollegeUniversity of CalicutKerala 673009India Inter-University Centre for Astronomy and Astrophysics(IUCAA) PB No.4GaneshkhindPune 411007India Department of Physics and Electronics CHRIST(Deemed to be University)Hosur Main RoadBangalore 560029India

We present the results from a long term X-ray analysis of Mrk.279 during the period 2018–*** use data from multiple missions–AstroSat,NuSTAR and XMM-Newton,for the *** X-ray spectrum can be modeled as a double Comptonization along with the presence of neutral Fe k.line emission,at all *** determined the source’s X-ray flux and luminosity at these different *** find significant variations in the source’s flux *** also investigate the variations in the source’s spectral components during the observation *** find that the photon index and hence the spectral shape follow the variations only over longer time *** probe the correlations between fluxes of different bands and their photon indices,and found no significant correlations between the parameters.

关键词： galaxies:Seyfert galaxies:individual(Mrk.335) X-rays:galaxies

First-principles calculations to investigate structural,electronic,magnetic,optical and thermodynamic properties of RE_(2)Rh_(3)Ge(RE=Pr,Sm)

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Journal of Rare Earths 2024年第7期42卷 1385-1393,I0007页

作者： A.Ezaier R.Masrour M.Hamedoun J.k.arbach A.Rezzouk.A.Hourmatallah N.Benzak.ur k.Bouslyk.ane Laboratory of Solid Physics Faculty of Sciences Dhar El MehrazSidi Mohamed Ben Abdellah UniversityBP 1796FezMorocco Equipe de Physique du Solide LaboratoiresLIPIEcole Normale SupérieureBensoudaFèsMorocco

In this paper,we analyzed the physical characteristics of the ternary alloys RE_(2)Rh_(3)Ge(RE=Pr and Sm)using the first principles calculation based on functional density theory integrated in the Wien2k.*** calculated formation energies of Pr_(2)Rh_(3)Ge and Sm_(2)Rh_(3)Ge are−5.3827 and−5.2782 eV/atom,respectively,showing that these alloys may exist *** results of the band structure and density of states indicate that all of the compounds tested are magnetic metals,and their magnetism is mostly related to the contribution of Pr and Sm *** total magnetic moments of Pr_(2)Rh_(3)Ge and Sm_(2)Rh_(3)Ge are 4.07245 and 11.16161μB/f.u,*** parameters such as heat capacity at constant pressure,entropy,Debye temperature,lattice volume,compressibility coefficients,and Grüneisen parameter alloys were calculated using the Gibbs algorithm and studied in depth over a large temperature range of 0-900 *** Debye temperature increases with increasing pressure and decreases with decreasing ***,the Debye temperatures calculated at p=0 GPa and T=300 k.are equal to be 342 and 322 k.for Pr_(2)Rh_(3)Ge and Sm_(2)Rh_(3)Ge,*** optical characteristics such as the real and imaginary portions of the dielectric function,the absorption coefficient,the energy-loss function,and the refractive index were investigated and discussed in more depth.

关键词： Magnetic metals Functional density theory Density of states Magnetic moment Optical and thermodynamic properties Rare earths