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Macrocellular vitreous carbon with the improved mechanical strength

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Frontiers of Materials Science 2015年第4期9卷 413-417页

作者： Oleg SMORYGO Alexander MARUKOVICH vitali mikutski Andika PRAMONO Powder Metallurgy Institute National Academy of Sciences of Belarus 41 Platonov str. Minsk 220005 Belarus Research Centre for Metallurgy and Materials Indonesian Institute of Sciences (LIPI) Kawasan Puspitek 470 Serpong 15314 Banten Indonesia

Vitreous carbons with regular macrocellular structure, open intercon- nected porosity, high specific strength and hydraulic permeability were synthesized by infiltration of the epoxy resin into the sacrificial template made from the carbamide granules. Polyvinylpyrrolidone （PVP） solution in ethanol was used as the template binder. When the resin setting and the template extraction had been performed, the resultant porous material was pyrolysed in the nitrogen flow. Depending on PVP concentration in the template binder, final vitreous carbons had the following properties： bulk density at 0.17-0.22g/cm3; porosity at 85.7%-89.0%; window size at 447-735pm; Darcian permeability coefficient at （0.64-9.5）×10-9m2; non-Darcian permeability coefficient at （0.53-3.36）×10-4 m. High specific strength of above 8×10^3 Pa/（kg.m-3） was attained.

关键词： vitreous carbon cellular material porous material

Tailoring properties of reticulated vitreous carbon foams with tunable density

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Frontiers of Materials Science 2016年第2期10卷 157-167页

作者： Oleg SMORYGO Alexander MARUKOVICH vitali mikutski Vassilis STATHOPOULOS Siarhei HRYHORYEU Vladislav SADYKOV Powder Metallurgy Institute National Academy of Sciences of Belarus 41 Platonov Str. Minsk 220005 Belarus Technological Educational Institute of Sterea Ellada Psahna Evias 34400 Greece Belarusian National Technical University 65 Nezavisimosty Ave. Minsk 220013 Belarus Boreskov Institute of Catalysis Sibrian Branch of Russian Academy of Sciences 5 Lavrentiev Ave. 630090 Novosibirsk Russia Novosibirsk State University 2 Pirogova Str. 630009 Novosibirsk Russia

Reticulated vitreous carbon （RVC） foams were manufactured by multiple replications of a polyurethane foam template structure using ethanolic solutions of phenolic resin. The aims were to create an algorithm of fine tuning the precursor foam density and ensure an open-cell reticulated porous structure in a wide density range. The precursor foams were pyrolyzed in inert atmospheres at 700℃, 1100℃and 2000℃, and RVC foams with fully open cells and tunable bulk densities within 0.09-0.42 g/cm3 were synthesized. The foams were characterized in terms of porous structure, carbon lattice parameters, mechanical properties, thermal conductivity, electric conductivity, and corrosive resistance. The reported manufacturing approach is suitable for designing the foam microstructure, including the strut design with a graded microstructure.

关键词： foam vitreous carbon reticulated cellular structure pyrolysis

Improving sintering kinetics and compositional homogeneity of 625 superalloy open-cell foams made by suspension impregnation method

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Transactions of Nonferrous Metals Society of China 2021年

作者： Oleg Smorygo vitali mikutski Anastasia Vazhnova Viachaslau Hancharou Serguei Tikhov Janagam Vinod Kumar Amol Anant Gokhale O.V.Roman Powder Metallurgy Institute Boreskov Institute of Catalysis， Siberian Branch， Russian Academy of Sciences Defence Metallurgical Research Laboratory Indian Institute of Technology Bombay

Open-cell IN 625 superalloy foams were prepared by suspension impregnation method which involves replication of pure nickel foam ligaments with a mixed powder suspension and subsequent heat treatments. The objective of the present study is to find a suitable method ensuring complete densification of the superalloy foam ligaments without using low-melting additives and achieving uniform chemical composition at moderate sintering temperatures. Forms prepared using the above methodology were evaluated for the microstructure and compositional variation across the foam ligaments by Scanning Electron Microscopy （SEM） coupled with Electron Dispersive Spectroscopy （EDS）. Quasi-static compressive properties of the foams were evaluated. It is shown that if elemental powders of Cr， Mo and Ni are used as additives to the superalloy powder suspension， high ligament density with uniform chemical composition conforming to the IN 625 specification are achieved at moderate sintering temperatures. These results are attributed to the formation of low melting eutectics and to acceleration of the diffusion kinetics due to the non-equilibrium thermodynamic conditions created by large compositional gradients in the presence of elemental powders.

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Improving sintering kinetics and compositional homogeneity of Inconel 625 superalloy open-cell foams made by suspension impregnation method

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Transactions of Nonferrous Metals Society of China 2021年第8期31卷 2388-2401页

作者： Oleg SMORYGO vitali mikutski Anastasia VAZHNOVA Viachaslau HANCHAROU Serguei TIKHOV Vinod Kumar JANAGAM Amol Anant GOKHALE O.V Roman Powder Metallurgy Institute 41Platonov str.Minsk 220005Belarus Boreskov Institute of Catalysis Siberian BranchRussian Academy of Sciences5pr.LavrentievaNovosibirsk 630090Russia Defence Metallurgical Research Laboratory KanchanbaghHyderabad 500058India Indian Institute of Technology Bombay PowaiMumbai 400076India

Open-cell Inconel 625 superalloy foams were prepared by suspension impregnation method which involves replication of pure nickel foam ligaments with a mixed powder suspension and subsequent heat *** objective of the present study is to find a suitable method ensuring complete densification of the superalloy foam ligaments without using low-melting additives and achieving uniform chemical composition at moderate sintering *** prepared using the above methodology were evaluated for the microstructure and compositional variation across the foam ligaments by scanning electron microscopy(SEM)coupled with electron dispersive spectroscopy(EDS).Quasi-static compressive properties of the foams were *** is shown that if elemental powders of Cr,Mo and Ni are used as additives to the superalloy powder suspension,high ligament density with uniform chemical composition conforming to the Inconel 625 specification is achieved at moderate sintering *** results are attributed to the formation of low melting eutectics and to acceleration of the diffusion kinetics due to the non-equilibrium thermodynamic conditions created by large compositional gradients in the presence of elemental powders.

关键词： superalloy foam suspension replication sintering diffusion microstructure

Decline of Eulia ministrana(Lepidoptera:Tortricidae)in polluted habitats is not accompanied by phenotypic stress responses

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Insect Science 2021年第5期28卷 1482-1490页

作者： vitali Zverev Mikhail V.Kozlov Department of Biology University of TurkuTurkuFinland

Env ironmental pollution is currently identified as one of the major drivers of rapid decline of insect populations,and this finding has revitalized interest in insect responses to *** tested the hypothesis that the pollution-induced decline of insect populations can be predicted from phenotypic stress responses expressed as morphological differences between populations inhabiting polluted and unpolluted *** explored populations of the brassy tortrix Eulia ministrana in subarctic forests along an environmental disturbance gradient created by long-lasting severe impacts of aerial emissions of the copper-nickel smelter in Monchegorsk,northwestern *** used pheromone traps to measure the population densities of this leafrolling moth and to collect specimens for assessment of three morphological stress indices:size,forewing melanization,and fluctuating asymmetry in wing *** length of *** increased by 10%,and neither forewing melanization nor fluctuating asymmetry changed from the unpolluted forest to the heavily polluted industrial ***,the population density of *** decreased 5 to 10 fold in the same pollution ***,none of the studied potential morphological stress indicators signaled vulnerability of *** to environmental pollution and/or to pollution-induced environmental *** conclude that insect populations can decline without any visible signs of *** use of morphological proxies of insect fitness to predict the consequences of human impact on insect populations is therefore risky until causal relationships between these proxies and insect abundance are deciphered.

关键词： copper-nickel smelter fluctuating asymmetry industrial melanism Kola Peninsula moth size pheromone trapping

Seismic response of deep circular tunnels subjected to S-waves:Axial bending

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Underground Space 2024年第4期17卷 267-279页

作者： Chatuphat Savigamin Antonio Bobet Osvaldo P.M.vitali HR Engineering Services Inc.MedleyFL 33166United States Lyles School of Civil Engineering Purdue UniversityWest LafayetteIN 47907United States Department of Civil Environmentaland Construction EngineeringUniversity of Hawaii at ManoaHonoluluHI 96822United States

Ovaling deformation of circular tunnels has received great interest from the tunneling community because this mode of seismicinduced deformation is considered the most ***,there is growing evidence that other deformation modes can also be important and thus need to be considered in *** study presents a new analytical solution to estimate axial bending(snaking),a mode of deformation caused by S-waves impinging on a tunnel parallel to the tunnel *** solution is developed using the soilstructure interaction approach with the assumption that the interface between the ground and the tunnel lining is frictionless(fullslip).Full dynamic numerical simulations are conducted to verify the new full-slip solution,together with the existing no-slip *** of dynamic amplification are also explored for both full-slip and no-slip interface conditions by changing the wavelength(or frequency)of the seismic input motions.

关键词： Seismic response of tunnels Analytical solutions Soil-structure interaction Axial bending Snaking S-waves

Gut-brain axis:does intestinal inflammation affect hippocampal neurogenesis and medulloblastoma development?

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Neural Regeneration Research 2023年第11期18卷 2381-2382页

作者： Arianna Casciati Mariateresa Mancuso Roberta vitali Simonetta Pazzaglia Biomedical Technologies Laboratory Agenzia Nazionale per le Nuove Tecnologiel’Energia e lo Sviluppo Economico Sostenibile(ENEA)RomeItaly

Gut-brain axis:does intestinal inflammation affect hippocampal neurogenesis and medulloblastoma development?Inflammatory bowel diseases (IBD) are a group of disorders that cause chronic inflammation in the intestines,associated with altered intestinal permeability,which in turn causes an immune response to enteric antigens in a gen etically susceptible *** incidence is high in industrialized countries and continuously rises in emerging economies.

关键词： inflammation diseases continuously

Video over IP using standard-compatible multiple description coding: an IETF proposal

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第5期7卷 668-676页

作者： vitali Andrea L BORNEO Antonio FUMAGALLI Marco RINALDO Roberto ST Microelectronics Strategy and System Technology Agrate Brianza (MI) 20041 Italy Center of Excellence for Research Innovation Education and Industrial Labs Partnership Milan 20133 Italy Department of Electrical Management and Mechanical Engineering University of Udine Udine 33100 Italy

Standard-compatible multiple description coding (MDC) and layered coding (LC) are efficient ways to ensure erasure resilient, scalable transmission of encoded multimedia sources via RTP, allowing a gradual degradation of the application quality with increasing packet loss rate and decreasing bandwidth/throughput on the network. In this paper we review the stan- dard-compatible framework proposed to IETF. Alternative techniques such as robust source coding and channel coding techniques (ARQ: automatic repeat request, FEC: forward error correction) are presented; their integration into the proposed framework is also discussed. The performances of MDC and LC either coupled with channel coding or not, are summarized by reference to current literature. Typical cases and examples are illustrated.

关键词： Video streaming, Robust coding, Multiple description coding, Layered coding, Loss/error resilience

Moving of a submarine under an ice cover in fluid of finite depth

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Journal of Hydrodynamics 2019年第3期31卷 562-569页

作者： Alexandra V. Pogorelova vitali L. Zemlyak Victor M. Kozin Sholom-A leichem Priamursky State University Birobidzhan Russia Institute of Machining and Metallurgy FEB RAS Komsomolsk-na-Amure Russia

The influence of a basin depth on ice cover deflections, when a submarine moves under it in fluid, is experimentally and theoretically analyzed. For a theoretical research the ice cover is modelled by an elastic floating plate, and the submarine is modelled by a source-sink system in a fluid flow. The problem is solved by means of asymptotic analysis and integral transformations. The experimental study is conducted with submarine models in the pool with the sizes L*B*H= 10m*3m*lm . The ice cover for experiments is modelled in two ways. The first way is the thin ice plate received by freezing of the surface layer of water at low temperatures. In the second case the rubber sheet floating on a reservoir surface is used. The special velocity (the velocity at which maximum values of the wave height are reached) is analyzed. It is obtained that the decrease of the basin depth leads to decrease of the special speed. For small speeds (less than the special speed) there is the fact that the basin depth decrease leads to the increase of the height of the flexural-gravity wave.

关键词： Ice cover submarine flexural gravity wave source-sink system