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Nanotechnology and Precision Engineering 2023年第2期6卷 41-47页

作者： Asha Singh Himanshu Srivastava rama Chari J.Jayabalan Nano Science Laboratory Materials Science SectionRaja Ramanna Centre for Advanced TechnologyIndore 452013India Lithography and Microscopy Laboratory Synchrotrons Utilization SectionRaja Ramanna Centre for Advanced TechnologyIndore 452013India

Nanoparticles with non-spherical shapes are now being widely used for various photonic *** observe experimentally that the magnitude as well as the time dependence of the transient absorption of a colloid of silver nanoplatelets depends on the relative polarization of the pump and probe *** have been a few reports about the dependence of the transient signal magnitude on polarization,but little information is available on its temporal *** a theoretical model,we show that this observed behavior arises from the fact that the energy absorption by a non-spherical nanoparticle depends on,among other factors,the nanoparticle orientation with respect to the pump and probe polarization *** is essential to consider this when estimating nanoparticle characteristics such as carrier thermalization time,carrier–phonon scattering time,and complex polarizability from transient absorption measurements.

关键词： Ultrafast dynamics Metal Nanoparticles Transient Absorption Polarization dependence

Fabrication of ceramic coatings on the biodegradable ZM21 magnesium alloy by PEO coupled EPD followed by laser texturing process

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Journal of Magnesium and Alloys 2021年第3期9卷 910-926页

作者： Hariprasad Sampatirao Saikiran Amruthaluru Premchand Chennampalli rama Krishna Lingamaneni Rameshbabu Nagumothu Department of Metallurgical and Materials Engineering National Institute of TechnologyTiruchirappalli 620015India Centre for Engineered Coatings International Advanced Research Centre for Powder Metallurgy and New Materials(ARCI)Hyderabad 500005India

Zirconia(ZrO_2)incorporated ceramic coatings were fabricated on biodegradable ZM21 Mg alloy by the PEO coupled with EPD ***,the sample surface was modified by laser texturing to improve the corrosion resistance,roughness and cell proliferation and growth *** corrosion performance of the fabricated samples along with the substrate was studied by electrochemical measurements under simulated body fluid(SBF)*** cell direct contact assay was conducted for the substrate and fabricated samples using L-929 mouse fibroblast cells for 24 *** phase contrast images of cell direct contact assay revealed that fabricated samples exhibited better contact and response with the fibroblast cells,compared to the *** addition of nanoparticles in the PEO process,called PEO coupled EPD process,resulted in attaining a higher thickness and improved corrosion performance of the samples than the PEO coated *** all the samples,laser surface textured PEO,and PEO-EPD coated samples unveiled enhanced corrosion resistance,cell growth,thereby enabling it as a suitable prototype for biodegradable implant applications.

关键词： ZM21 ZrO_(2)nanoparticle PEO-EPD Laser texturing Corrosion resistance L-929 cells

Nodule study in Albizia chinensis in relation to nitrogen metabolism,morphology and biomass

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Journal of Forestry Research 2020年第1期31卷 57-63页

作者： Vandana Kushawaha Satya prasad Chaukiyal Plant Physiology Discipline Forest Research Institute

Morphology,biomass,nitrate reductase(NR)and nitrogenase activity in Albizia chinensis(Osb.)*** were assessed on monthly and seasonal basis for 1 *** NR and nitrogenase activity was higher during the rainy season,reaching a maximum in ***,activity decreased through autumn and reached a minimum value during *** and dry biomass of nodules increased gradually from summer to the rainy season and then started decreasing with the onset of winter as nodules began to *** four developmental stages of the nodules that correspond to their increasing age,NR and nitrogenase activity remained low in stage 1 nodules and peaked in stage *** activity of both enzymes further decreased with increasing age(stage 2 to stage 4).Morphological features such as shape,diameter and color varied considerably among the developmental *** 1 nodules were cream-colored,oval to heartshaped with smallest average diameter whereas at stage 2,they became bilobed to *** the other hand,stage 3 nodules had the largest average diameter and were multilobed in *** 4 nodules that correspond to the senescing stage were dark brown to black,multilobed,flattened and hollow due to degeneration of nodular tissue.

关键词： Nitrogenase activity Nitrate reductase(NR)activity Nodule biomass Nodule morphology Nodule senescence

Support pressure for circular tunnels in two layered undrained clay

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 135-148页

作者： Bibhash Kumar Jagdish prasad Sahoo Department of Civil Engineering National Institute of TechnologyUttarakhand246174India Department of Civil Engineering Indian Institute of TechnologyRoorkee247667India

To estimate the required support pressure for stability of circular tunnels in two layered clay under undrained condition,numerical solutions are developed by performing finite element lower bound limit analysis in conjunction with second-order cone *** support system is assumed to offer uniform internal compressive pressure on its *** the literature,it is known that the stability of tunnels depends on the overburden pressure acting over it,which is a function of undrained cohesion and unit weight of soil,and cover of *** a tunnel is constructed in layered undrained clay,the stability depends on the undrained shear strength,unit weight,and thickness of one layer relative to the other *** the present study,the solutions are presented in a form of dimensionless charts which can be used for design of tunnel support systems for different combinations of ratios of unit weight and undrained shear strength of upper layer to those of lower layer,thickness of both layers,and total soil cover depth.

关键词： Finite elements Layered clay Limit analysis Stability of tunnels

Effect of multiple rings on side force over an ogive-cylinder body at subsonic speed

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Chinese Journal of Aeronautics 2018年第6期31卷 1181-1188页

作者： Priyank KUMAR J.K.prasad Department of Space Engineering & Rocketry Birla Institute of Technology

Experiments and computations were performed over an ogive-cylinder body having an lift-to-drag ratio of 16 at a diameter Reynolds number of 29000. The side force on the slender body augments with increasing angles of attack for the case without a ring. This increase was mainly due to the increase in the asymmetry of the existing vortex pair in the wake of the body. Attempts were made to completely reduce the existing side force at the angle of attack ranging from 35° to 45°.Three rectangular cross-sectioned circumferential rings having a height of 3% of the local diameter were placed at axial distances of 2.5, 3.5 and 4.5 times the base diameter from the tip of the body so as to reduce the side force. The results obtained indicate that inclusion of three rings completely alleviated the side force on the slender body at the angle of attack ranging from 0° to 45°. The presence of rings was found to alter the growth of the vortices that helped in the reduction of the side force. Computations performed were in reasonable agreement with the experiments.

关键词： Asymmetric vortex High angle of attack Ogive Side force Slender body Vortex lift

Low velocity impact studies of E-glass/epoxy composite laminates at different thicknesses and temperatures

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Defence Technology（防务技术） 2019年第6期15卷 897-904页

作者： T.Sreekantha Reddy P.rama Subba Reddy Vemuri Madhu Defence Metallurgical Research Laboratory

Low velocity impact experiments were carried out on E-glass/epoxy composite laminates having varying thicknesses at sub zero and elevated temperatures using hemi spherical steel impactor of 16 mm diameter with impact energies in the rage of 50-150 *** performance of the laminates was assessed in terms of energy absorption,maximum displacement,peak force and failure *** indicated that the effect of temperature on energy absorption of the laminate is negligible although the laminates are embrittling at sub zero *** it has influence on failure behaviour and *** force has increased linearly with increase in laminate thickness from 5 to 10 *** it got reduced by 25% when temperature was increased from-20℃ to 100℃,Based on experimental results,laminate perforation energies were predicted using curve fitting *** analysis was carried out using Taguchi method to identify the global effects of various parameters on laminate performance and confirmed that the laminate thickness has significant influence as compared to temperature,for the studied range.

关键词： Laminates Glass fibres Impact behaviour Delamination

Hepatotoxic Alterations Induced by Inhalation of Trichloroethylene (TCE) in Rats

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Biomedical and Environmental Sciences 2001年第4期14卷 325-332页

作者： PRADEEPKUMAR A.K.prasad 等 AnimalHouse InhalationToxicologyDivision IndustrialToxicologyResearchCenterP.O.Box80M.G.MargLucknow－226001India

Objective Trichloroethylene (TCE) is one of the most potent organic unsaturated solvents being used in dry cleaning, metal degreasing, thinner for paints varnishes and electroplating, etc. and has been reported to be a hepatotoxicant through oral and dermal exposure. However, its inhalation toxicity data is very limited in the literature due to the fact that the exposure levels associated with these effects were usually not reported. Hence, inhalation toxicity study was carried out for hepatotoxic studies. Method Inhalation toxicity studies was carried out by exposing rats to TCE for 8, 12 and 24 weeks in a dynamically operated whole body inhalation chamber. Sham treated control rats were exposed to compressed air in the inhalation chamber for the same period. Results Significant increase in liver weight (liver enlargement) appearance of necrotic lesions with fatty changes and marked necrosis were observed after longer duration (12 and 24 weeks) of TCE exposure. The lysosomal rupture resulted in increased activity of acid and alkaline phosphatase alongwith reduced glutathione content and total increased sulfhydryl content in liver tissue. Conclusion TCE exposure through Inhalation route induces hepatotoxicity in terms of marked necrosis with fatty changes and by modulating the lysosomal enzymes.

关键词： METABOLISM LIVER MICE GLUTATHIONE EXPOSURE BODY

New pseudo-dynamic analysis of two-layered cohesive-friction soil slope and its numerical validation

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1492-1508页

作者： Suman HAZARI Sima GHOSH Richi prasad SHARMA Department of Civil Engineering National Institute of TechnologyAgarala 799046India

Natural slopes consist of non-homlogeneous soil profiles with distinct characteristics from slopes made of homogeneous *** this study,the limit equilibrium modified pseudo-dynamic method is used to analyze the stability of two-layered c-φsoil slopes in which the failure surface is assumed to be a logarithmic *** zero-stress boundary condition at the ground surface under the seismic loading condition is *** formulations derived from an analytical method are proposed for the predicting the seismic response in two-layered soil.A detailed parametric study was performed in which various parameters(seismic accelerations,damping,cohesion,and angle of internal friction)were *** results of the present method were compared with those in the available *** present analytical analysis was also verified against the finite element analysis results.

关键词： layered soil limit equilibrium method seismic analysis damping PLAXIS

Review Article on Condition Assessment of Structures Using Electro-Mechanical Impedance Technique

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Structural Durability & Health Monitoring 2022年第2期16卷 97-128页

作者： Krishna Kumar Maurya Anupam Rawat rama Shanker Department of Civil Engineering MNNIT AllahabadPrayagraj211004India

Structural health monitoring(SHM)is a process for determination of presence,location,severity of damages and remaining life of the *** is widely applied in aerospace,mechanical and civil engineering sys-tems to assess the conditions of structures to improve the operation,safety,serviceability and reliability,*** are various SHM techniques for monitoring the health of structures such as global response based and local *** occur in the structures due to its inability to withstand intended design loadings,physical environment and chemical ***,damage identification is necessary to improve the durability of the structures for protection against catastrophic *** research paper is focused on elec-tro-mechanical impedance(EMI)technique which is one of the techniques based on smart *** smart materials are utilized for monitoring the health of the *** are used for damage determination and its quantification for the interrogated *** in admittance or impedance signature shows the existence of damage in the ***,the different statistical methods viz.,root mean square deviation(RMSD),mean absolute percentage deviation(MAPD),covariance(Cov),and correlation coefficient(CC)are used for the quantification of *** material such as piezoelectric materials,its properties and applica-tions are also *** this paper,the implementation of EMI technique based on different recent advances in smart materials and their appropriateness have been ***,the reviewed investigations are significant for the monitoring of real-life *** presented paper is the compact state-of-the-art for EMI technique which is used for *** examination will be valuable to infrastructural health monitoring and engineering applications in respect to innovative research directions.

关键词： Structural health monitoring condition assessment EMI technique PZT patches damages

Modeling of a long sand-pack for heavy crude oil through depletion tests utilizing methane gas

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Petroleum 2021年第2期7卷 188-198页

作者： Bashir Busahmin rama Rao Karri Stephen Tyson Morteza Jami Petroleum&Chemical Engineering Universiti Teknologi BruneiBrunei Darussalam

With the enormous increase in the demand for crude oil,and decrease in the resources of conventional oil reservoirs,there is a great need to understand heavy or foamy oil-gas drive mechanism to maximize the oil and gas *** analyze the real movement of non-viscous heavy oil flow,the characteristic features of the oil-gas mixture has to be estimated to forecast the future potential supply from a heavy oil *** important question in heavy oil flow under solution gas drive is whether the behaviour of depletion tests can be simulated to model the heavy oil flow *** main objective of this research is to develop a reliable numerical model for modelling heavy oil flow calibrated with controlled solution gas drive experiments,and that makes a novelty in this *** this paper,CMG-STARS model which is capable of simulating solution gas drive tests that matched the research *** heavy oil recovery model can determine the relative permeability curves for oil and gas in the dualphase system using Corey’s *** a depletion rate of 0.0418 psi/min,the maximum cumulative oil and gas production was observed to be 13,000 cm^(3)and 8500 cm^(3),*** results from the bottom hole pressure and the block pressure simulation runs indicate that the fluid properties such as surface tension plays a significant role in the gas bubble *** results are promising,and helps to understand the complex behaviour of heavy oil reservoirs and thus can improve heavy oil recovery.

关键词： Depletion rate Simulation Gas fluid dual-phase Sand-pack Heavy oil reservoir Methane gas