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Nonlinear stability of functionally graded material(FGM)sandwich cylindrical shells reinforced by FGM stiffeners in thermal environment

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Applied Mathematics and Mechanics(English Edition) 2017年第5期38卷 647-670页

作者： d.v.dUNG N.T.NGA l.K.HOA Faculty of Mathematics Mechanics and InformaticsVietnam National UniversityHanoi 100000Vietnam Faculty of Basic Science Military Logistic AcademyHanoi 100000Vietnam

In this paper, donnell＇s shell theory and smeared stiffeners technique are improved to analyze the postbuckling and buckling behaviors of circular cylindrical shells of stiffened thin functionally graded material （FGM） sandwich under an axial loading on elastic foundations, and the shells are considered in a thermal environment. The shells are stiffened by FGM rings and stringers. A general sigmoid law and a general power law are proposed. Thermal elements of the shells and reinforcement stiffeners are considered. Explicit expressions to find critical loads and postbuckling load-deflection curves are obtained by applying the Galerkin method and choosing the three-term approximate solution of deflection. Numerical results show various effects of temperature, elastic foundation, stiffeners, material and geometrical properties, and the ratio between face sheet thickness and total thickness on the nonlinear behavior of shells.

关键词： functionally graded material (FGM) stiffened cylindrical shell sandwich,thermal environment

Experience gained in analyzing severe accidents for WWER RP using CC SOCRAT

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Frontiers in Energy 2021年第4期15卷 872-886页

作者： S.I.PANTYUSHIN А.v.lITYSHEv A.v.NIKOlAEvA O.v.AUlOvA d.l.GASPAROv v.v.ASTAKHOv M.A.BYKOv Non-stationary Thermohydraulics department OKB Gidropress JSC 142103PodolskRussia

The current Russian regulatory documents on the safety of nuclear power plant(NPP)specify the requirements regarding design basis accidents(dBAs)and beyond design basis accidents(BdBAs),including severe accidents(SAs)with core meltdown,in NPP design(NP-001-15,NP-082-07,and others).For a rigorous calculational justification of BdBAs and SAs,it is necessary to develop an integral CC that will be in line with the requirements of regulatory documents on verification and certification(Rd-03-33-2008,Rd-03-34-2000)and will allow for determining the amount of data required to provide information within the scope stipulated by the requirements for the structure of the safety analysis report(SAR)(NP-006-16).The system of codes for realistic analysis of severe accidents(SOCRAT)(formerly,thermohydraulics(RATEG)/coupled physical and chemical processes(SvECHA)/behavior of core materials relocated into the reactor lower plenum(HEFEST))was developed in Russia to analyze a wide range of SAs at NPP with water-cooled water-moderated power-generating reactor(WWER)at all stages of the *** to the code and broadening of its applicability are continually being pursued by the code developers(Nuclear Safety Institute of the Russian Academy of Sciences(IBRAE RAN))with OKB Gidropress JSC and other ***,the SOCRAT/В1 code can be used as a base tool to obtain realistic estimates for all parameters important for computational justification of the reactor plant(RP)safety at the in-vessel stage of SAs with fuel *** perform analyses using CC SOCRAT/В1,the experience gained during execution of thermohydraulic codes is applied,which allows for minimizing the uncertainties in the results at the early stage of an accident *** study presents the results of the work performed in 2010–2020 in OKB Gidropress JSC using the CC SOCRAT/В*** have been considered to develop calculational models and analyze SAs using CC *** process,which is cle

关键词： system of codes for realistic analysis of severe accidents(SOCRAT) design basis accidents(dBAs) severe accidents(SAs) computer code(CC) nuclear power plant(NPP)design water-cooled water-moderated(WWER) modeling model safety requirements

Assessing the Sustainability of Underground Space Usage——A Toolkit for Testing Possible Urban Futures

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Journal of Mountain Science 2011年第2期8卷 211-222页

作者： d.v.l.HUNT I.JEFFERSON C.d.F.ROGERS The University of Birmingham

A description of the future as it might be without forecasts, predictions and trend analysis can be referred to as a 'future scenario'. An abundance of scenarios literature exists in which numerous pictures have been painted of changed future worlds. However, upon closer inspection it becomes apparent that virtually all of this literature refers to changes occurring above ground, ignoring the inevitable consequences (or opportunities) for sustainable use of underground space, not least in densely populated urban areas, some of which may be underlain by complex geological conditions. This paper reports on the development (to date) of an 'Urban Futures' (UF) toolkit for sub-surface environments (including infrastructure and utilities) which, through use of 'key' questions 'sustainable' indicators and a 'contextual' narrative, allows for better definition and measured performance of underground space in the UK, both today and in the future. The toolkit explores possible uses for underground space within 4 plausible and well-cited future scenarios (i.e. New Sustainability Paradigm, Fortress World, Market Forces and Policy Reform). This forms part of a much larger generic toolkit which the UF research team are developing for exploring possible future scenarios over a range of UK urban regeneration case study areas.

关键词： urban futures toolkit underground space sustainability

New approach to formation of coatings on Mg-Mn-Ce alloy using a combination of plasma treatment and spraying of fluoropolymers

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Journal of Magnesium and Alloys 2022年第4期10卷 1033-1050页

作者： d.v.Mashtalyar K.v.Nadaraia I.M.Imshinetskiy S.l.Sinebryukhov S.v.Gnedenkov Institute of Chemistry FEB RAS 159 Pr.100-letiyaVladivostok 690022Russia Far Eastern Federal University 10 Ajax BayRussky IslandVladivostok 690922Russia

This paper presents a method of the formation of composite polymer-containing coatings on a Mg–Mn–Ce magnesium alloy by forming a ceramic-like layer using plasma electrolytic oxidation(PEO)and subsequent spraying superdispersed polytetrafluoroethylene *** coating composition and their morphological features were studied by SEM,EdS,GdOES,and *** presented data confirm the embedding of fluoropolymer in the PEO *** evaluation of the corrosion properties of the formed composite polymer-containing coatings indicates a decrease in the corrosion current density by more than 3 orders of magnitude in comparison with the base PEO *** incorporation of a fluoropolymer in a PEO layer by more than 32%increases the load value at which abrasion of the coating to the substrate occurs and reduces the wear of the coating by more than 27 fold in comparison with the PEO *** has been established that composite coatings possess hydrophobic properties:the value of the contact angle attains 152°.

关键词： Plasma electrolytic oxidation Polytetrafluoroethylene Composite coatings Corrosion Wear Superhydrophobicity

Structurally Flexible 2d Spacer for Suppressing the Electron-Phonon Coupling Induced Non-Radiative decay in Perovskite Solar Cells

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Nano-Micro letters 2024年第9期16卷 325-340页

作者： Ruikun Cao Kexuan Sun Chang liu Yuhong Mao Wei Guo Ping Ouyang Yuanyuan Meng Ruijia Tian lisha Xie Xujie lü Ziyi Ge Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and devices Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201People’s Republic of China School of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315211People’s Republic of China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049People’s Republic of China Center for High Pressure Science and Technology Advanced Research(HPSTAR) Shanghai 201203People’s Republic of China

This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron-phonon coupling of perovskite in perovskite solar cells(PSCs).via A-site cation engineering,a weaker electron-phonon coupling in perovskite has been achieved by introducing the structurally soft cyclohexane methylamine(CMA^(+))cation,which could serve as a damper to alleviate the mechanical stress caused by lattice oscillations,compared to the rigid phenethyl methylamine(PEA^(+))*** demonstrates a significantly lower non-radiative recombination rate,even though the two types of bulky cations have similar chemical passivation effects on perovskite,which might be explained by the suppressed carrier capture process and improved lattice geometry *** resulting PSCs achieve an exceptional power conversion efficiency(PCE)of 25.5%with a record-high opencircuit voltage(v_(OC))of 1.20 v for narrow bandgap perovskite(FAPbI_(3)).The established correlations between electron-phonon coupling and non-radiative decay provide design and screening criteria for more effective passivators for highly efficient PSCs approaching the Shockley-Queisser limit.

关键词： Electron-phonon coupling A-site cation engineering Non-radiative recombination

Anneal-free ultra-low loss silicon nitride integrated photonics

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light(Science & Applications) 2024年第8期13卷 1565-1577页

作者： debapam Bose Mark W.Harrington Andrei Isichenko Kaikai liu Jiawei Wang Nitesh Chauhan Zachary l.Newman daniel J.Blumenthal department of Electrical and Computer Engineering University of California Santa BarbaraSanta BarbaraCA 93106USA Octave Photonics LouisvilleCO 80027USA

Heterogeneous and monolithic integration of the versatile low-loss silicon nitride platform with low-temperature materials such as silicon electronics and photonics,III–v compound semiconductors,lithium niobate,organics,and glasses has been inhibited by the need for high-temperature annealing as well as the need for different process flows for thin and thick *** techniques are needed to maintain the state-of-the-art losses,nonlinear properties,and CMOS-compatible processes while enabling this next generation of 3d silicon nitride *** report a significant advance in silicon nitride integrated photonics,demonstrating the lowest losses to date for an anneal-free process at a maximum temperature 250℃,with the same deuterated silane based fabrication flow,for nitride and oxide,for an order of magnitude range in nitride thickness without requiring stress mitigation or *** report record low anneal-free losses for both nitride core and oxide cladding,enabling 1.77 dBm-1 loss and 14.9 million Q for 80 nm nitride core waveguides,more than half an order magnitude lower loss than previously reported sub 300℃ *** 800 nm-thick nitride,we achieve as good as 8.66 dBm-1 loss and 4.03 million Q,the highest reported Q for a low temperature processed resonator with equivalent device area,with a median of loss and Q of 13.9 dBm-1 and 2.59 million each *** demonstrate laser stabilization with over 4 orders of magnitude frequency noise reduction using a thin nitride reference cavity,and using a thick nitride micro-resonator we demonstrate OPO,over two octave supercontinuum generation,and four-wave mixing and parametric gain with the lowest reported optical parametric oscillation threshold per unit resonator *** results represent a significant step towards a uniform ultra-low loss silicon nitride homogeneous and heterogeneous platform for both thin and thick waveguides capable of linear and nonlinear photonic circuits and integrat

关键词： resonator thick free

Effect of silica source on photocatalytic properties of Bi_(2)O_(3)/Bi_(2)SiO_(5) heterostructure

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生物质资源与工程(英文) 2023年第2期8卷 176-186页

作者： O.d.Arefieva M.S.vasilyeva l.A.Zemnukhova d.P.Opra d.A.Nikolaeva v.v.Tkachev d.H.Shlyk Far Eastern Federal University Vladivostok 690922Russian Federation Institute of Chemistry Far-Eastern BranchRussian Academy of SciencesVladivostok 690922Russian Federation

The Bi_(2)O_(3)/Bi_(2)SiO_(5) heterostructures were obtained with various samples of silica as a precursor:on the basis of biogenic silica isolated from rice husk and rice straw and the silica of mineral ori-gin.A mixture of Bi(NO_(3))_(3) and SiO_(2) with a mass content of 15%was used for synthesizing all the *** transform infrared(FT-IR)spectroscopy,scanning electron microscope(SEM),X-ray phase,X-ray fluorescence,and ultraviolet-visible diffused reflectance spectroscopy(Uv-vis dRS)were used to systematically characterize as-obtained *** of methyl orange in neutral aqueous solutions(pH=6.8)under Uv irradiation was studied to evaluate their photocatalytic ***,bandgaps,the value of the zero charge point,and photo-catalytic activity of the samples depended on the characteristics of the original *** degree of methyl orange degradation reached the maximum values(81%−85%)for samples based on precipitated silica from rice husks,straw,and the minimum value(16%)for a composite with thermal silica from rice *** based on thermal silica from rice husks and reagents from mineral raw materials did not statistically differ from each other in the degree of methyl orange degradation(67%−74%).

关键词： Biogenic silica Heterostructures Photocatalysis Rice husk Rice straw

Evaluating the effectiveness of marine actinobacterial extract and its mediated titanium dioxide nanoparticles in the degradation of azo dyes

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Journal of Environmental Sciences 2014年第4期26卷 775-782页

作者： S Priyaragini S veena d Swetha l Karthik G Kumar K v Bhaskara Rao Molecular and Microbiology Research laboratory Environmental Biotechnology Division School of Bio Sciences and Technology VIT University

Aim of the present study was to synthesize titanium dioxide nanoparticles （YiO2 NPs） from marine actinobacteria and to develop an eco-friendly azo-dye degradation method. A total of five actinobacterial isolates were isolated from Chennai marine sediments, Tamilnadu, India and analyzed for the synthesis of TiO2 NPs using titanium hydroxide. Among these, the isolate PSv 3 showed positive results for the synthesis of TiO2 NPs, which was confirmed by Uv analysis. Further characterization of the synthesized TiO2 NPs was done using XRd, AFM and FI＇-IR analysis. Actinobacterial crude extract and synthesized TiO2 NPs was found efficient in degrading azo dye such as Acid Red 79 （AR-79） and Acid Red 80 （AR-80）. degradation percentage was found to be 81% for AR-79, 83% for AR-80 using actinobacterial crude extract and 84% for AR-79, 85% for AR-80 using TiO2 NPs. Immobilized actinobacterial ceils showed 88% for AR-79 and 81% for AR- 80, dye degrading capacity. degraded components were characterized by FT-IR and GC-MS analysis. The phytotoxicity test with 500 μg/ml of untreated dye showed remarkable phenotypic as well as cellular damage to Tagetes erecta plant. Comparatively no such damage was observed on plants by degraded dye components. In biotoxicity assay, treated dyes showed less toxic effect as compared to the untreated dyes.

关键词： actinobacteria azo dye degradation ZiO2 NPs biotoxicity Tagetes erecta

Effect of low Feed Rate FSP on Microstructure and Mechanical Properties of Extruded Cast 2285 Aluminum Alloy

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Journal of Materials Science & Technology 2007年第5期23卷 614-618页

作者： l.Karthikeyan v.S.Senthilkumar d.viswanathan S.Natarajan department of Mechanical Engineering Panimalar Engineering CollegeChennai-103TamilNaduIndia department of Mechanical Engineering College of EngineeringAnna UniversityChennai-025TamilNaduIndia

Friction stir processing （FSP）, a variation of FSW （friction stir welding） is an emerging surface engineering technology that can locally eliminate casting defects and refine microstructures, thereby improving the mechanical properties of material. FSP can also produce fine grained microstructures through the thickness to impart superplasticity. The technology involves plunging a rapidly rotating, non consumable tool, comprising a profiled pin and larger diameter shoulder, into the surface and then traversing the tool across the surface. The pin and the shoulder friction heat the surface which alters the grain structure in the processed area thereby improving the mechanical properties. This paper presents the effects of FSP on microstructure and mechanical properties of extruded cast 2285 aluminum alloy at three different feed rates viz. 10, 12 and 15 mm/min. With the increase in the feed speed the material was observed to have increased impact strength. FSP also increased the tensile and yield strengths with increases in hardness and ductility values also. The observation has been listed in detail and pictorially represented.

关键词： Friction stir processing Feed rate Fine grain microstructure