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Processing and design methodologies for advanced and novel thermal barrier coatings for engineering applications

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Particuology 2016年第4期14卷 1-28页

作者： vijay kumar Balasubramanian Kandasubramanian Department of Materials Engineering Defence Institute of Advanced Technology Girinagar Pune 411025 India

Thermal barrier coating is a crucial thermal insulation technology that enables the underlying substrate to operate near or above its melting temperature. Such coatings bolster engineers＇ perpetual desire to increase the power and efficiency of gas turbine engines through increasing the turbine inlet tempera- ture. Advances in recent years have made them suitable for wider engineering and defense applications, and hence they are currently attracting considerable attention. A thermal barrier coating system is itself dynamic; its components undergo recurrent changes in their composition, microstructure and crystalline phases during its service life. Nevertheless, the performance of multi-layered and multi-material sys- tems tailored for high temperature applications is closely linked to the deposition process. The process improvements achieved so far are the outcome of increased understanding of the relationship between the coating morphology and the operating service conditions, as well as developments in characterization techniques. This article presents a comprehensive review of various processing techniques and design methodologies for thermal barrier coatings. The emphasis of this review is on the particle technology; the interrelationship between particle preparation, modification and the resulting properties, to assist developments in advanced and novel thermal barrier coatings for engineering applications.

关键词： Thermal barrier coatingAir plasma sprayElectron beam-physical vapor depositionThermally grown oxideYttria-stabilized zirconiaThermal conductivity

Syncytes during male meiosis resulting in 2n pollen grain formationin Lindelofia longiflora ***

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Journal of Systematics and Evolution 2011年第5期49卷 406-410页

作者： vijay kumar SINGHAL Pawan kumar RANA Puneet kumar Department of Botany Punjabi University

Lindelofia longiflora(Royle ex Benth.) ***(Cl.) Brand(Family:Boraginaceae) is investigated cytologically(n = 12) for the first time from the cold deserts of Pangi Valley,Chamba District(Himachal Pradesh) in *** report the formation of syncytes and 2n pollen grains in the *** meiosis,the majority of the pollen mother cells(PMCs) exhibited 12 bivalents,equal segregation of chromosomes during anaphases,regular tetrads,and normal-sized pollen grain ***,two proximate PMCs fused during the early stages of prophase-I and resulted in the formation of *** frequency of syncytes in the accession is rather low,at 25 out of 1866(1.33%).Such syncyte PMCs are detectable during meiosis due to their larger size compared to typical *** syncytes or polyploid cells showed normal 24 bivalents and depicted perfectly regular meiotic *** the products of such PMCs yield 2n or larger sized pollen grains that are almost double the size of typical normal or n pollen *** origin of syncytes as a consequence of the fusion of meiocytes during the early stages of meiosis-I could be attributed to low temperature stress conditions prevailing in the Pangi Valley,where temperature during May and June dip to below freezing,the time the plants enters the reproductive/flowering bud *** is possible that such apparently fertile 2n pollen grains originating from syncytes might play a role in the origin of intraspecific polyploids in the species.

关键词： bivalents cold deserts low temperature stress Pangi Valley PMCs pollen grains.

SAR interferometric coherence analysis for snow cover mapping in the western Himalayan region

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International Journal of Digital Earth 2011年第1期4卷 78-90页

作者： vijay kumar Gopalan Venkataraman Centre of Studies in Resources Engineering Indian Institute of Technology BombayPowaiMumbai 400076India

Information of snow cover(SC)over Himalayan regions is very important for regional climatological and hydrological *** monitoring of SC in the Himalayan region is essential for water supply to hydropower stations,irrigation requirements,and flood *** remote sensing has all weather,day and night earth observation capability unlike optical remote *** this study,spaceborne synthetic aperture radar interferometric(InSAR)coherence analysis is used to monitor SC over Himalayan rugged *** feasibility of monitoring SC using synthetic aperture radar(SAR)interferometry depends on the ability to maintain coherence over InSAR pair acquisition time ***-1/2 InSAR coherence and ENVISAT ASAR InSAR coherence images are analyzed for SC *** sets of winter and of snow free months of the Himalayan region are taken for interferogram *** images of the available data sets show maximum decorrelation in most of the area which indicates massive snowfall in the region in the winter season and melting in the *** showing coherence loss due to decorrelation is mapped as a snowcovered *** result is validated with field observations of snow depth and it is found that standing snow is inversely related to coherence in the Himalayan region.

关键词： SAR InSAR coherence snow cover digital earth microwave remote sensing

An Efficient Update Strategy for Content Synchronization in Content-Centric Networking(CCN)

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China Communications 2019年第1期16卷 108-118页

作者： Nidhi Lal Shishupal kumar vijay kumar Chaurasiya Thapar University IIIT Allahabad

Content-centric Networking(CCN) is progressively flattering the substitutable approach to the Internet architecture through illuminating information(content) dissemination on the Internet with content *** emergent proportion of Internet circulation has expectant adjusting Content-centric architecture to enhance serve the user prerequisites of accessing *** recent years,one of the key aspects of CCN is ubiquitous in-network caching,which has been widely received great attention in research *** foremost shortcoming of in-network caching is that content producers have no awareness about where their content is put in *** routers in CCN have caching capabilities,therefore,each and every content router can cache the content item in its storage *** is problematic in the case in which a producer wishes to update or make the changes in its content *** this paper,we present an approach regarding how to address this issue with a scheme called efficient content update(ECU).Our proposed ECU scheme achieves content update via trifling packets that resemble contemporary CCN communication messages with the use of additional *** measure the performance of ECU scheme by means of simulations and make available a comprehensive exploration of its results.

关键词： content-centric network routing performance caching content delivery

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Anticancer and cytotoxic properties of the latex of Calotropis procera in a transgenic mouse model of hepatocellular carcinoma

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World Journal of Gastroenterology 2006年第16期12卷 2517-2522页

作者： Tenzin Choedon Ganeshan Mathan Soneera Arya vijay L kumar vijay kumar Virology Group International Centre for Genetic Engineering and BiotechnologyAruna Asaf Ali MargNew Delhi-110067India Department of Pharmacology All India Institute of Medical SciencesAnsari NagarNew Delhi-110029India

AIM： To evaluate the anticancer property of the dried latex （DL） of Calotropis procera, a tropical medicinal plant, in the X15-myc transgenic mouse model of hepatocellular carcinoma and to elucidate its mechanism of action in cell culture. METHODS： The young transgenic mice were orally fed with the aqueous suspension of DL （400 mg/kg for 5 d/wk） for 15 wk and their liver was examined for histopathological changes at 20 wk. Serum levels of vascu- lar endothelial growth factor （VEGF） were also measured in these animals. To characterize the active fraction, DL was extracted with petroleum ether followed by methanol. The methanolic extract was sub-fractionated on a silica gel G column using a combination of non-polar and polar solvents and eleven fractions were obtained. Each fraction was analysed for cytotoxic effect on hepatoma （Huh7） and non-hepatoma （COS-1） cell lines and nontransformed hepatocytes （AML12） using tetrazolium （MTT） assay. Finally, the mechanism of cell death was investigated by measuring the levels of Bcl2, caspase 3 and DNA fragmentation. RESULTS： DL treatment of mice showed a complete protection against hepatocarcinogenesis. No adverse effect was observed in these animals. The serum VEGF level was significantly lowered in the treated mice as compared to control animals. Cell culture studies revealed that the methanolic extract of DL as well as its fraction 8 induced extensive cell death in both Huh-7 and COS-1 cells while AML12 cells were spared. This was accompanied by extensive fragmentation of DNA in Huh-7 and COS-1 cells. No change in the levels of canonical markers of apoptosis such as Bcl2 and caspase 3 was observed. CONCLUSION： DL of C. procera has the potential for anti-cancer therapy due to its differentJable targets and non-interference with regular pathway of apoptosis.

关键词： Calotropis procera Transgenic mice Hepatocellular carcinoma Cytotoxicity Anticancer agent Differential killing

Single image defogging by gain gradient image filter

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Science China(Information Sciences) 2019年第7期62卷 225-227页

作者： Dilbag SINGH vijay kumar Computer Science and Engineering Department Apex Institute of Technology Chandigarh University Computer Science and Engineering Department Thapar Institute of Engineering and Technology

Dear editor,With the advancements in computer vision applications, the image defogging methods have received a lot of consideration. Defogging methods are extensively utilized in civil and military areas such as target detection, traffic surveillance,remote sensing. Therefore, the development of visibility restoration models has become a task of great interest and *** and kumar [1] have proved that the dark

关键词： image Single image defogging by gain gradient image filter

VLSI scaling methods and low power CMOS buffer circuit

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Journal of Semiconductors 2013年第9期34卷 92-99页

作者： vijay kumar Sharma Manisha Pattanaik Department of Information Technology ABV-Indian Institute of Information Technology & Management

Device scaling is an important part of the very large scale integration （VLSI） design to boost up the success path of VLSI industry, which results in denser and faster integration of the devices. As technology node moves towards the very deep submicron region, leakage current and circuit reliability become the key issues. Both are increasing with the new technology generation and affecting the performance of the overall logic circuit. The VLSI designers must keep the balance in power dissipation and the circuit＇s performance with scaling of the devices. In this paper, different scaling methods are studied first. These scaling methods are used to identify the effects of those scaling methods on the power dissipation and propagation delay of the CMOS buffer circuit. For mitigating the power dissipation in scaled devices, we have proposed a reliable leakage reduction low power transmission gate （LPTG） approach and tested it on complementary metal oxide semiconductor （CMOS） buffer circuit. All simulation results are taken on HSPICE tool with Berkeley predictive technology model （BPTM） BSIM4 bulk CMOS files. The LPTG CMOS buffer reduces 95.16% power dissipation with 84.20% improvement in figure of merit at 32 nm technology node. Various process, voltage and temperature variations are analyzed for proving the robustness of the proposed approach. Leakage current uncertainty decreases from 0.91 to 0.43 in the CMOS buffer circuit that causes large circuit reliability.

关键词： LPTG buffer power dissipation propagation delay scaling nanoscale CMOS figure of merit

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Response of thermal source in a transversely isotropic thermoelastic half-space with mass diffusion by using a finite element method

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Chinese Physics B 2012年第8期21卷 307-313页

作者： Ibrahim A.Abbas Rajneesh kumar vijay Chawla Department of Mathematics Faculty of Science and Arts-KhulaisKing Abdulaziz UniversityJeddahSaudi Arabia Department of Mathematics Faculty of ScienceSohag UniversitySohagEgypt Department of Mathematics Kurukshetra UniversityKurukshetra-136119HaryanaIndia

The two-dimensional problem of generalized thermoelastic diffusion material with thermal and diffusion relaxation times is investigated in the context of the Lord-Shulman theory. As an application of the problem, a particular type of thermal source is considered and the problem is solved numerically by using a finite element method. The components of displacement, stress, temperature distribution chemical potential and mass concentration are obtained. The resulting quantities are depicted graphically for a special model. An appreciable effect of relaxation times is observed on various resulting quantities.

关键词： thermoelastic diffusion thermal source finite element method relaxation time

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Butein imparts free radical scavenging, anti-oxidative and proapoptotic properties in the flower extracts of Butea monosperma

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BIOCELL 2012年第2期36卷 63-71页

作者： ANURADHA SEHRAWAT vijay kumar Virology Group International Centre for Genetic Engineering and BiotechnologyAruna Asaf Ali MargNew Delhi 110067India

The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver *** understand the pharmacological basis of its beneficial effects,the extracts of dried flowers in water,methanol,butanol,ethyl acetate and acetone were evaluated for free radical scavenging and pro-apoptotic activities in cell cultures(human hepatoma Huh-7 cell line and immortalized AML-12 mouse hepatocytes).Butrin and butein-the active constituents of flower extracts-were used as reference *** levels of cell injury markers like lactate dehydrogenase,glutathione and lipid peroxidation and primary antioxidant enzymes glutathione S-transferase and catalase were also *** aqueous and butanolic extracts exhibited better 2,2-diphenyl-1-picrylhydrazyl scavenging and cytotoxic activities in hepatoma cells than in immortalized ***,butein inhibited 2,2-diphenyl-1-picrylhydrazyl radical better than *** aqueous and butanolic extracts were further investigated for hepatoprotection against carbon tertrachloride-induced biochemical changes and cell *** extracts,just as butrin and butein,significantly reversed the cellular glutathione levels and lipid peroxidation,and glutathione–S-transferase *** dehydrogenase leakage and cell death were also ***,only butein revived the catalase ***,the butein content of Butea monosperma flower extracts is important for free radical scavenging activity,apoptotic cell death and protection against oxidative injury in hepatic cells.

关键词： butrin cytotoxicity hepatoprotection methanol extract free radical scavenging