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A comprehensive review of rectangular duct solar air heaters featuring artificial roughness

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Clean Energy 2024年第5期8卷 186-217页

作者： Ravi Shankar Rajeev Kumar Arun Kumar pandey Deep Singh Thakur Department of Mechanical Engineering Rajkiya Engineering College BandaUttar Pradesh 210201India Department of Mechanical Engineering Institute of Engineering&TechnologyLucknowUttar Pradesh 226021India Department of Mechanical Engineering Bundelkhand Institute of Engineering&TechnologyJhansiUttar Pradesh 284128India

Solar air heaters(SAHs)are widely used solar thermal systems with applications in diverse ***,its effectiveness is re-strained by low convective heat transfer(HT)coefficients at the absorber plate,leading to inefficient HT,and the elevated temperature of the absorber plate causes significant heat losses,reducing thermal *** study addresses these challenges by introducing ribs or roughness on the absorber plate creating turbulence in the airflow,resulting in significant *** research inves-tigates various rib configurations,the influence of rib parameters,performance methods,and arrangements to evaluate their HT and friction *** these rib configurations,a comparative analysis is done on various factors such as the Nusselt number ratio,thermal enhancement factor,friction factor ratio,and thermal efficiency to optimize distinct roughness parameters and rib ar-rangement *** study also provides valuable recommendations from existing literature,offering insights into the effective design,prospects,and implementation of SAH systems.

关键词： solar air heater artificial roughness low heat transfer heating solar energy

Investigating the Evolution of Amati Parameters with Redshift

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Research in Astronomy and Astrophysics 2024年第1期24卷 188-200页

作者： Meghendra Singh Darshan Singh Kanhaiya Lal pandey Dinkar Verma Shashikant Gupta Delhi Metro Rail Corporation Limited New Delhi 110001India GD Goenka University Gurugram 122103India Department of Physics Mata Raj Kaur Institute of Engineering and TechnologyRewari 123401India Department of Physics School of Advanced SciencesVellore Institute of TechnologyVellore 632014India

Gamma-ray bursts(GRBs) are among the brightest objects in the Universe and, hence, can be observed up to a very high redshift. Properly calibrated empirical correlations between intensity and spectral correlations of GRBs can be used to estimate the cosmological parameters. However, the possibility of the evolution of GRBs with redshift is a long-standing puzzle. In this work, we used 162 long-duration GRBs to determine whether GRBs below and above a certain redshift have different properties. The GRBs are split into two groups, and we fit the Amati relation for each group separately. Our findings demonstrate that estimations of the Amati parameters for the two groups are substantially dissimilar. We perform simulations to investigate whether the selection effects could cause the difference. Our analysis shows that the differences may be either intrinsic or due to systematic errors in the data, and the selection effects are not their true origin. However, in-depth analysis with a new data set comprised of 119 long GRBs shows that intrinsic scatter may partly be responsible for such effects.

关键词： Cosmology gamma rays:general (cosmology:)large-scale structure of universe galaxies:high-redshift

Lap-Shear Performance of Weld-Bonded Mg Alloy and Austenitic Stainless Steel in Three-Sheet Stack-Up

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 342-353页

作者： Sunusi Marwana Manladan Mukhtar Fatihu Hamza Singh ramesh Zhen Luo School of Materials Science and Engineering Tianjin UniversityTianjin 300350China Department of Mechanical Engineering Faculty of EngineeringBayero UniversityKano 3011Nigeria Department of Mechanical Engineering College of EngineeringPrince Sattam bin Abdulaziz University11942 AlkharjSaudi Arabia Department of Mechanical Engineering Faculty of EngineeringUniversity of Malaya50603 Kuala LumpurMalaysia

With the growing interest in utilizing Mg and austenitic stainless steel(ASS)in the automotive sector,joining them together in three-sheet configuration is ***,achieving this task presents considerable challenges due to the large differences in their physical,metallurgical and mechanical *** overcome these challenges,the feasibility of using weld-bonding to join Mg alloy/ASS/ASS was *** nugget formation,interface characteristics,microstructure and mechanical properties of the joints were *** results show that the connection between the Mg alloy and upper ASS was achieved through the combined effect of the cured adhesive and weld-brazing in the weld *** the other hand,a metallurgical bond was formed at the ASS/ASS *** Mg nugget microstructure exhibited fine columar grains composed predominantly of primaryα-Mg grains along with a eutectic mixture ofα-Mg andβ-*** nugget formed at the ASS/ASS interface consisted largely of columnar grains of austenite,with some equiaxed dendritic grains formed at the centerline of the *** weld-bonded joints exhibited an average peak load and energy absorption of about 8.5 kN and 17 J,respectively(the conventional RSW joints failed with minimal or no load application).The failure mode of the joints changed with increasing welding current from interfacial failure via the Mg nugget/upper ASS interface to partial interfacial failure(part of the Mg nugget was pulled out of the Mg sheet).Both failure modes were accompanied by cohesive failure in the adhesive zone.

关键词： Weld-bonding Resistance spot welding Austenitic stainless steel Mg alloy Failure mode

Spatio-temporal variation of depth to groundwater level and its driving factors in arid and semi-arid regions of India

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Regional Sustainability 2024年第2期5卷 103-122页

作者： Suchitra pandey Geetilaxmi MOHAPATRA Rahul ARORA Department of Economics and Finance Birla Institute of Technology&SciencePilani333031India

Climate change and increasing anthropogenic activities,such as over-exploitation of groundwater,are exerting unavoidable stress on groundwater *** study investigated the spatio-temporal variation of depth to groundwater level(DGWL)and the impacts of climatic(precipitation,maximum temperature,and minimum temperature)and anthropogenic(gross district product(GDP),population,and net irrigated area(NIA))variables on DGWL during *** study considered DGWL in 113 observation wells and piezometers located in arid western plains(Barmer and Jodhpur districts)and semi-arid eastern plains(Jaipur,Ajmer,Dausa,and Tonk districts)of Rajasthan State,*** methods were employed to examine the annual and seasonal patterns of DGWL,and the generalized additive model(GAM)was used to determine the impacts of climatic and anthropogenic variables on *** 1994-2020,except for Barmer District,where the mean annual DGWL was almost constant(around 26.50 m),all other districts exhibited increase in DGWL,with Ajmer District experiencing the most *** results also revealed that 36 observation wells and piezometers showed a statistically significant annual increasing trend in DGWL and 34 observation wells and piezometers exhibited a statistically significant decreasing trend in ***,32 observation wells and piezometers showed an statistically significant increasing trend and 37 observation wells and piezometers showed a statistically significant decreasing trend in winter;33 observation wells and piezometers indicated a statistically significant increasing trend and 34 had a statistically significant decreasing trend in post-monsoon;35 observation wells and piezometers exhibited a statistically significant increasing trend and 32 observation wells and piezometers showed a statistically significant decreasing trend in pre-monsoon;and 36 observation wells and piezometers reflected a statistically significant increasing trend and 30 observation

关键词： Climate change Generalized additive model(GAM) Depth to groundwater level(DGWL) Climatic and anthropogenic variables Arid and semi-arid regions

Optimization of variables and assessment of in-vitro and in-vivo antihyperlipidemic activity of Eudragit RS nanoparticles containing simvastatin

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Particuology 2024年第7期90卷 189-198页

作者： Bina Gidwani Vishal Jain Veenu Joshi Ravindra Kumar pandey Shiv Shankar Shukla Amber Vyas Columbia Institute of Pharmacy Raipur(C.G.)India University Institute of Pharmacy Pt Ravishankar Shukla UniversityRaipur(C.G.)India Center for Basic Science and Research Pt Ravishankar Shukla UniversityRaipur(C.G.)India

Simvastatin, a BCS class II drug, is associated with poor aqueous solubility, first-pass metabolism and short half-life. In the present work, nanoparticles were prepared and evaluated. Optimization of formulation and process parameters was done through the use of independent and dependent variables. Preliminary studies were done to determine suitable range of the concentration of Eudragit polymer (10%–30%) and the ratio of drug to polymer (1:1 to 1:5) for the formation of nanoparticles by emulsification and a solvent evaporation technique. Results revealed that the mean size of nanoparticles was affected by stirring speed from 5000 RPM, 8000 RPM, and 12000 RPM. The results of increase in association efficiency and percent yield with increase in amount of drug from 100 mg, 150 mg, and 200 mg in selected range were observed. In-vitro release studies showed that two formulations possess highest initial burst and slow sustained drug release. There was 2.93-fold decrease in total cholesterol and 3.27-fold increases in triglyceride level during in-vivo study.

关键词： Simvastatin Eudragit RS 100 Nanoparticles Hyperlipidemia

Expert perspective on technological choice for cooking energy transition in Nepal

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Clean Energy 2024年第4期8卷 40-48页

作者： Dipesh KC Sunil prasad Lohani Poushan Shrestha Chunyu Xue Renewable and Sustainable Energy Laboratory(RSEL) Department of Mechanical EngineeringKathmandu UniversityKathmanduNepal Biomass Energy and Environmental Engineering Research Center Beijing University of Chemical TechnologyBeijingChina

Solid biomass dominates as the primary source of cooking energy,especially in rural households of *** use of solid biomass has a detrimental effect on health,exacerbates the burden of biomass collection,and hampers access to clean *** the factors influencing the choice of modern cooking fuels is crucial to improving energy security and resilience and easing the transition to clean *** study evaluates technological choices for the transition in cooking energy from the perspective of experts working in the government,non-government,and academia sectors.A structured questionnaire survey was prepared with five criteria and nine cooking technology ***-one experts responded to the survey,and their responses were analyzed using the analytical hierarchy *** study reveals that efficiency and capital cost are the primary criteria for selecting cooking tech*** most suitable clean cooking technology is an induction stove followed by a hot plate,while the least preferred technology is a Bayupankhi stove followed by two-pothole mud improved cooking *** ensure the robustness of the method,sensitivity analysis was performed on the two primary criteria efficiency and capital cost of the cooking *** analysis revealed robust and consistent rankings of *** study should help create a conducive environment for relevant stakeholders and policymakers to formulate and implement relevant policies and strategies to accelerate the cooking energy transition in Nepal.

关键词： cooking technologies cooking energy transition electric cooking residential sector analytical hierarchy process

In vitro and in silico approach for the evaluation of enzyme inhibitory potential of Kadipatta (Murraya koenigii) collected from western Nepal

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Clinical Traditional Medicine and Pharmacology 2024年第4期5卷 44-53页

作者： Suman Prakash Pradhan Ishan Subedi Kapil Adhikari Ashok GC Sujan Prakash Pradhan Mukti Ram Aryal Gopal prasad Ghimire Bishnu prasad pandey Department of Chemical Science and Engineering Kathmandu UniversityPO Box:6250 KavreDhulikhelBagmati Province 45210Nepal Aquatic Ecology Centre Kathmandu UniversityDhulikhel 45210Nepal Department of Environmental Science and Engineering Kathmandu UniversityDhulikhel 45210Nepal Department of Botany Tri-Chandra Multiple CampusKathmandu 44600Nepal Department of Applied Sciences Western Regional CampusPokhara 33700Nepal

Background:Murraya koenigii(L.)Spreng.(Rutaceae)is an evergreen shrub distributed over the sub-tropical to lower temperate climatic zone of Nepal which has been used as spice in culinary practice and traditionally being used to treat bites of poisonous animals,dysentery,skin diseases,vomiting,diarrhea,and ***:The main objective of this study is to study the enzyme inhibition potential of different extracts of *** leaves collected from western ***:Total flavonoid content,total phenolic content,in vitro antioxidant,𝛼α-amylase,lipase,elastase,tyrosinase,and cholinesterase inhibition activities analysis of *** in ethyl acetate,methanol,and water extract were *** addition,high-resolution mass spectrometry-based profiling of flavonoid molecules and their docking analysis were ***:Results revealed the noteworthy radical scavenging activity of ethyl acetate extract against ABTS and *** the analyzed enzymes,*** extracts revealed the highest inhibitory potential towards acetylcholinesterase(AChE)and butyrylcholinesterase(BChE)and only water extract showed the inhibition of *** HPLC-ESI-QTOF-MS analysis revealed the presence of Rutin,Quercetin,Ferulic acid,Hyperoside,Kaempferol-7-O-glucoside,and Morin in ***,in silico docking analysis revealed the significant binding energy of these flavonoid molecules;especially Rutin with ***:The ethyl acetate and methanolic extracts of *** showed paramount flavonoid and phenolic content along with noteworthy potential towardsthe inhibition of neuro-degradative enzymes such as BChE which can be characterized further for pharmacological *** study on the isolation of metabolites and their pharmacological properties from *** is recommended.

关键词： Murraya koenigii 𝛼α-amylase Lipase Elastase Tyrosinase Cholinesrerase

Influence of edaphic factors on distribution and condition of Himalayan silver birch(Betula utilis ***)communities in the northwestern Indian Himalayas

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Journal of Mountain Science 2024年第2期21卷 590-606页

作者： Khashti DASILA Renu RAWAL Tanay BARMAN Sher Singh SAMANT Anita pandey Veena PANDE G.B.Pant National Institute of Himalayan Environment Almora 263643India Centre of Excellence on Sustainable Land Management Indian Council of Forestry Research and EducationDehradun 248006India Uttarakhand State Council for Science&Technology Dehradun 248015India Department of Biotechnology Graphic Era(Deemed to be University)Dehradun 248002India Department of Biotechnology Kumaun UniversityNainital 263136India

The basic concept of phytosociology is crucial for the assessment of species composition and dynamic ecological succession of forests supporting ecological services,functions,disturbance,and resilience that lead to the development of integrated areas such as ecological niche modeling and contribute to identifying the valuable bio-indicators which can be used in framing conservation and management *** is one of the most dominant tree species of treeline ecotone in the Himalayan *** species is also considered as indicator species for monitoring the past and recent climate change *** current study was carried out in the natural populations of *** from the sub-alpine zone of North-western Indian *** birch dominated forest harbors a total of 305 plant species comprising Angiosperms(51 families,160 genera and 277 species),Gymnosperms(03 families,05 genera and 07 species)and Pteridophytes(07 families,11 genera and 21 species)with Asteraceae,Ranunculaceae and Rosaceae as dominant *** forests are found dominant in shady moist habitat and North West *** characteristics,anthropogenic and developmental activities affect the population structure of *** and associated ***,the species has fair regeneration status in the study *** acidic nature of soil pH and spatial variation in edaphic characteristics may be due to geographical differences,rooting patterns and litter accumulation of below and above-ground *** estimation of a representative population of *** from each site showed that TAGBD,TCD and TBD were found maximum in ST3(Hamta Pass II site).The CCA analysis determined that environmental variables such as altitude,organic matter,available phosphorous,organic carbon,available nitrogen,and electrical conductivity played a significant role in determining tree species composition and distribution in *** dominated forests.

关键词： Species composition Indicator species Biomass North-western Indian Himalaya Regeneration Environmental variables

Numerical modelling of post-failure behaviors of coal specimens

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 514-531页

作者： Ajeet Yadav Bhaskara Behera Gauri Shankar prasad Singh Sanjay Kumar Sharma Department of Mining Engineering Indian Institute of Technology(Banaras Hindu University)VaranasiUttar Pradesh221005India

A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having different w/h *** model was developed based on back-analysis of the complete stress-strain behavior of specimens belonging to six different Indian coal seams with different w/h ratios of 0.5 *** was found that the simultaneous degradation of the cohesion and friction angle of the Mohr-Coulomb rock material characterizes the post-peak strength behavior of the *** resulting expressions are simplistic as they require parameters that can be easily determined using uniaxial and triaxial compression ***,the developed model was validated by simulating the triaxial tests of coal specimens with different sizes under varying confining stresses and comparing its findings with the published test *** study showed that its implementation in the numerical model could reproduce laboratory-observed mechanical response,deformation behavior,and failure mechanism very closely.

关键词： Strain softening Dilatancy Interface Shape effect Residual strength