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Effect of cold-working on corrosion induced damage in lug joints

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Defence Technology（防务技术） 2024年第6期36卷 175-182页

作者： Ramanath M.n Chikmath L. Murthy h. Department of Aerospace Engineering Indian Institute of Technology-MadrasChennai 600036India Department of Aeronautical Engineering KLS Gogte Institute of TechnologyBelagavi 590008India

Lug joints are preferred joineries for transferring heavy loads to parent components in aerospace *** experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement between the pin and *** causes damage of different sizes and shapes near the *** degradation due to corrosion-induced damage is modelled as a through-pit at one of the identified critical locations through stress *** effect of this pit on fatigue crack initiation life is ***-hole is pre-stressed by cold-working and the benefits of inducing plastic wake on the intended performance of the lug joint during the damages due to corrosion are brought out and compared with.non-cold-worked *** analysis is performed on this lug joint with *** results obtained highlight the benefits of cold-working and the methodology can be extended to damage growth and analyse the effect of surface treatments for better structural integrity of components of aerospace vehicles.

关键词： Lug joint Corrosion Crack initiation Cold-working Structural integrity

Recent advances in FeCl_(3)-photocatalyzed organic reactions via hydrogen-atom transfer

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Ch.nese Chemical Letters 2024年第9期35卷 32-40页

作者： Xiao-Ya Yuan Cong-Cong Wang bing Yu Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhou 450001China national Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass Nanjing Forestry UniversityNanjing 210037China

In recent years,FeCl_(3)-photocatalyzed direct C–h/Si–h bond functionalization reactions have attracted huge *** those transformations,chlorine radical(Cl·)could be generated from FeCl_(3)via a ligandto-metal charge transfer(LMCT)/homolysis process under light *** resulting chlorine radical subsequently acts as a hydrogen atom transfer(hAT)agent to abstract the hydrogen atom of aliphatic C–h,O–h,or Si–h bonds to give the corresponding C/Si/O-centered radicals for various organic *** this review,we summarized the recent advances in the application of FeCl_(3)as a hAT photocatalyst for the C/Si–h functionalization to construct C–C,C–n,C–Si,C–S,C–B,and C-P bonds.

关键词： FeCl_(3) Photocatalysis Ligand-to-metal charge transfer hydrogen atom transfer Chlorine radical

Late neoproterozoic to early Cambrian high-grade metamorphism from Mikir hills(Assam-Meghalaya gneissic Complex,northeast India):Implications for eastern Gondwana assembly

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Geoscience Frontiers 2024年第5期15卷 256-282页

作者： Rahul nag h.hrushikesh.nath.n Cogné n.Prabhakar Department of Earth Sciences Indian Institute of Technology BombayPowaiMumbaiMaharastra 400076India Geological Survey of India Northeastern RegionGuwahatiAssam 781005India Géosciences Rennes UMR6118CNRS Universitéde RennesFrance

Mikir hills region,which represents the eastern segment of the Assam-Meghalaya Gneissic Complex(AMGC)in northeast India,constitutes part of the Eastern *** Mikir hills preserves multiple metamorphic and magmatic events ranging from Early Mesoproterozoic to Early *** of these events,documenting the late neoproterozoic to early Cambrian tectonothermal events is helpful in correlating the continental blocks of Eastern *** present an integrated study involving field relations,petrology,P-T history and zircon-monazite geochronology of hitherto poorly studied pelitic and quartzo-feldspathic gneisses from the Mikir hills *** gneisses have experienced at least three deformation events(D_(1),D_(2) and D_(3))with dominant foliation indicated by EnE-WSW striking and shallow-moderately dipping(neissic *** peak metamorphism in pelitic and quartzo-feldspathic gneisses is characterized by garnet(core)-K-feldspar-sillimanite-plagioclase-bio tite-rutile-quartz-ilmenite-melt and garnet-plagioclase-K-feldspar-biotite-quartz-ilmenite-melt assemblages,*** application of thermobarometric methods constrains the peak P-T conditions of 7.5-8.4 kbar at 674-778℃and 6.7-7.4 kbar at 601-618℃for pelitic and quartzofeldspathic gneisses,*** results are consistent with the values estimated using phase equilibria modelling and melt reintegration *** results of pseudosection modelling suggests a clockwise P-T path for pelitic gneisses involving migmatisation during peak metamorphism followed by near isothermal decompression from 8.0 to 8.6 kbar at 768-780℃to 4.0-5.0 kbar at 720-765℃.In contrast,quartzo-feldspathic gneisses preserved slightly lower peak P-T conditions at 3.8-4.6 kbar and 590-650℃.The U-Pb zircon dating of migmatised pelitic and quartzo-feldspathic gneisses yielded concordant ages of 1647±11 Ma and 1590±7 Ma,*** dates represent the inherited igneous protolith components,possibly

关键词： Gondwana Assam-Meghalaya Gneissic Complex Migmatisation neoproterozoic Geochronology P-T-t history

Ramsey numbers of Trees Versus Multiple Copies of Books

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 600-612页

作者： Xiao-bing GUO Si-nan hU Yue-jian PEnG School of Mathematical Sciences Luoyang Normal UniversityLuoyang 471934China School of Mathematics Hunan UniversityChangsha 410082China

Given two graphs G and h,the Ramsey number R(G,h) is the minimum integer n such that any two-coloring of the edges of K_(n) in red or blue yields a red G or a blue *** v(G) be the number of vertices of G and χ(G) be the chromatic number of *** s(G) denote the chromatic surplus of G,the number of vertices in a minimum color class among all proper χ(G)-colorings of *** showed that R(G,h)≥(v(G)-1)(χ(h)-1)+s(h) if G is connected and v(G)≥s(h).A connected graph G is h-good if R(G,h)=(v(G)-1)(χ(h)-1)+s(h).Let th denote the disjoint union of t copies of graph h,and let G∨h denote the join of G and *** a complete graph on n vertices by K_(n),and a tree on n vertices by T_(n).Denote a book with.n pages by B_(n),i.e.,the join K_(2) ∨■.Erd?s,Faudree,Rousseau and Schelp proved that T_(n) is B_(m)-good if n≥*** this paper,we obtain the exact Ramsey number of T_(n) versus 2B_(2).Our result implies that T_(n) is 2B_(2)-good if n≥5.

关键词： ramsey number ramsey goodness tree book

DFT investigation of half-metallic ferromagnetic rare earth based spinels Mgho_(2)Z_(4)(Z=S,Se)

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Journal of Rare Earths 2024年第1期42卷 121-128,I0005页

作者： Maiza Zanib Mumtaz Manzoor n.A.noor M.Waqas Iqbal Mazia Asghar h.h.hegazy A.Laref Department of Physics Riphah International UniversityLahore CampusPakistan Research Centre for Advanced Materials Science King Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics and Astronomy College of ScienceKing Saud UniversityRiyadh11451Saudi Arabia

half-metallic ferromagnetism,mech.nical as well as thermoelectric properties for rare earth-based spinels Mgho_(2)Z_(4)(Z=S,Se)were investigated using density functional theory(DFT).Structural optimization was done with Perdew-Burke-Ehrenzorf(PBE)sol-generalized gradient approximation(GGA)to calculate the lattice constant of both spinels comparable to experimental *** addition,Born stability criteria and negative formation energy show that our studied spinels are also structurally and dynamically stable in the cubic *** ferromagnetic(FM)state stability,we also calculated the energy differences among FM,antiferromagnetic(AFM),and non-magnetic(nM)***,Curie temperatures of ferromagnetic phases were also *** used Trans-Blaha improved BeckeJohnson(TB-mBJ)potential functional for electronics as well as magnetic characteristics,which lead to the consistent explanation of half-metallic ferromagnetism,representing the whole band-occupancy in material with exact detail of density of states(DOS).The stable FM state was examined in spinels due to the exch.nge splitting of ho cation consisting of p-d hybridizations compatible with the result achieved for electronics band structure and ***,spin magnetic moment was explained in terms of anion,cation,and sharing charge on studied *** addition,the calculated thermoelectric properties clearly show that operation range of these systems may be utilized by future experimental works for identifying the potential applications of these systems.

关键词： ho-based spinels DFT simulations Mech.nical parameters Electronic properties hM ferromagnetism Figure of merit

A hydrodynamic modelling of wave-activated bodies for wavelet marine regions

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Clean Energy 2024年第2期8卷 35-47页

作者： J.S.Peh Mohammed W.Muhieldeen n.h.Shuaib Mech.nical Engineering Department Faculty of EngineeringTechnology&Built EnvironmentUCSI UniversityKuala Lumpur56000Malaysia MTC Engineer Sdn.Bhd Shah AlamSelangorMalaysia

Recently,most wave energy research has targeted sea areas with high power density under extreme wave conditions for *** trend often leads to higher energy costs for wave power ***,many marine areas with low power density,characterized by wavelet conditions and less destructive forces th.n extreme wave conditions,remain ***,this study aimed to propose a wave-activated body model for sea regions with wavelet *** wave-activated body design process encompassed site selection,parameter determination,geometry design,comparison and performance evaluation using the AnSYS®AQWA *** results indicated that the proposed device achieved the desired heave motion,with an amplitude range of 1.2 to-2.5 m,validating its potential for deployment in marine regions with wavelet ***,while the proposed design is optimized for wavelet conditions,it was found to have potential limitations in extreme wave *** observation emphasizes the challenge of formulating a generalized design suitable for both ***,it is pivotal for wave-activated body designs to be customized based on the specific ocean conditions they target,underscoring the need for specialized designs of wave energy converters that consider the unique wave characteristics of their deployment sites.

关键词： wave energy converter South Ch.na sea renewable and sustainable energy wavelet AnSYS AQWA hydrodynamic wave-activated bodies

Synthesis of straight-chain C_(49)h_(100) alkane using a modular splicing strategy

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Journal of Energy Chemistry 2024年第5期92卷 414-421页

作者： bing Ma Jingqing Tian Xueling Lang Shutao Lei Bolong Li Ch.n Zhao Sh.nghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China School of Materials Science and Engineering Nankai UniversityTianjin 300350China

Ultra-long n-alkanes are highly valuable in both scientific research and as major constituents of specialty high-melting-point *** conventional methods(e.g.,Fischer–Tropsch(FT),ethylene oligomerization,and polyethylene cracking)typically resulting in wide n-alkane distributions,the elaborate design strategy presented herein allows the direct synthesis of pure,long n-alkanes using a modular splicing method with acetone,furfural,and fatty acid anhydrides or acyl chlorides as *** herein approach is based on a simple four-step catalytic reaction scheme involving C–C chain elongation and C–O bond *** synthesized pure n-alkanes had a carbon chain length as high as C_(49)(total yield of 49%).The synthesis approach also allows to selectively prepare n-alkanes with even and odd carbon numbers ranging from C15 to C_(49).This process represents a great breakthrough in the synthesis of long-chain pure n-alkanes,surpassing the carbon number limitations reported in previous methodologies.

关键词： Straight-chain alkane Aldol condensation F-Cacylation hydrodeoxygenation

Tilted global solar irradiance in Bahrain:an experimental study

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Clean Energy 2024年第2期8卷 27-34页

作者： n.Vasilikos C.Georgantopoulou h.Alajaimi S.h.Almajed M.Ahmed D.Mathioulakis School of Mech.nical Engineering Bahrain PolytechnicIsa TownPO Box 33349Kingdom of Bahrain School of Mech.nical Engineering National Technical University of AthensHeroon Polytechniou 7 StZografos 15773AthensGreece

In the present work,tilted global solar irradiance data are presented and analysed,measured for a period of 1 year on the campus of Bahrain Polytechnic,Kingdom of Bahrain,from both a fixed photovoltaic panel and a moving one via a two-axis solar *** fixed panel faces south with an angle of 26°with respect to the horizontal,coinciding with the local geographical *** second panel is moved by two motors,controlled by a global positioning system and suitable software so that the Sun’s rays are perpendicular to the panel surface.A pyranometer is installed on each panel,recording the tilted global solar irradiance,stored by using a data *** analysis of the data obtained shows a 33%solar energy gain on an annual basis for the moving panel(2780 versus 2088 kWh/m^(2) on the fixed panel).More importantly,in June,wh.n the energy demand in Bahrain is elevated due to the increased residential cooling loads,the solar energy received by the moving panel is 54.7%higher compared with that of the fixed *** a percentage basis,the increase in solar energy from the moving panel is profound in the early morning and late evening ***,the reduction in the solar energy received by the fixed panel from May to June does not appear in the moving panel because of the adjustable orientation of the *** the year,the mean daily solar power varies between 0.37 and 0.56 kW/m^(2) for the fixed panel,and 0.45 and 0.70 kW/m^(2) for the moving *** winter,solar energy fluctuations are elevated due to erratic weather conditions that present a peak standard deviation of 28%of the corresponding *** data presented are useful for potential solar investments in Gulf countries.

关键词： tilted solar irradiance renewable energy solar tracking photovoltaic Gulf Cooperation Council Countries

Empirical model for fusion cross sections of Ca-induced reactions

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Ch.nese Physics C 2024年第3期48卷 126-132页

作者： Reddi Rani.L n.Sowmya K.n Sridhar h C.Manjunatha M.M.Armstrong Arasu Department of Physics St.Joseph's College(Autonomous)Affiliated to Bharathidasan UniversityTiruchirappalli620002TNIndia Department of Physics Govt.First.Grade CollegeChikkaballapur-562101KarnatakaIndia Department of Physics Govt.First.Grade CollegeMalur-563160KarnatakaIndia Department of Physics Govt.First.Grade CollegeDevanahalli-562110KarnatakaIndia

A new empirical formula for the astrophysical S-factor has been suggested as a function of the Coulomb interaction parameter,center of mass energy,and barrier *** 22 fusion reactions with ^(40,48)Ca as projectiles were considered for different targets,leading to compound nuclei with atomic and mass numbers varying between 40≤Z≤≤Z≤112 and 88≤A≤27888≤A≤278,*** fusion cross-sections have been estimated using the geometric factor,the Gamow-Sommerfield factor,and the empirical formula for the *** study's findings showed better agreement with those of available experiments wh.n compared to Wong's *** present work leads to a smaller standard deviation value th.n Wong's formula wh.n used to correlate the experimental data of calcium-induced fusion ***'s formula provides a good approximation of fusion cross-sections wh.n the center of mass energy is below the fusion barrier wh.n compared to above the fusion barrier.

关键词： fusion cross-sections Wong formula Gamow-Sommerfield-factor Geometric-factor S-factor