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Improved strength and ductility of high alloy containing Al–12Zn–3Mg–2.5Cu alloy by combining non-isothermal step rolling and cold rolling

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International Journal of Minerals,Metallurgy and Materials 2017年第2期24卷 179-185页

作者： v.v.Ravikumar S.Kumaran Department of Metallurgical and Materials Engineering National Institute of TechnologyTamil Nadu 620015India

Al-12Zn-3Mg-2.5Cu alloy was prepared using a liquid metallurgy route under the optimized conditions. A sample cut from the ingot was rolled non-isothermally from 400℃ to 100℃ in 100℃ steps, with 15% reduction in thickness; it was then cold rolled isothermally at room temperature for 85% reduction. The cold-rolled alloys were characterized by electron microscopy, hardness test, and tensile test to elucidate their structural evolution and evaluate their mechanical behavior. In the results, the cast alloy consists of a-aluminum and various intermetallic compounds. These compounds are segregated along the grain boundaries, which makes the alloy difficult to roll at room tem- perature. The combined effect of non-isothermal step rolling and cold rolling results in the nano/microsized compounds distributed uniformly in the matrix. The hardness is substantially increased after rolling. This increase in hardness is attributed to the ultra-fine grain size, fine-scale intermetallic compounds, and structural defects （e.g., dislocations, stacking faults, and sub-grains）. The ultimate tensile strength of the rolled alloy is approximately 628 MPa with 7% ductility.

关键词： aluminum zinc magnesium copper alloys non-isothermal cold rolling mechanical properties intermetallic compounds struc-ture defects

Superconducting magnetic energy storage for stabilizing grid integrated with wind power generation systems

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Journal of Modern Power Systems and Clean Energy 2019年第2期7卷 400-411页

作者： Poulomi MUKHERJEE v. v. RAO Applied Superconductivity Laboratory Cryogenic Engineering Centre Indian Institute of TechnologyKharagpur

Due to the interconnection of various renewable energies and adaptive technologies, voltage quality and frequency stability of modern power systems are becoming erratic. Superconducting magnetic energy storage(SMES),for its dynamic characteristic, is very efficient for rapid exchange of electrical power with grid during small and large disturbances to address those *** addition,SMES plays an important role in integrating renewable sources such as wind generators to power grid by controlling output power of wind plant and improving the stability of power *** application of SMES in various power system operations depends on the proper location in the power system, exact energy and power ratings and appropriate controllers. In this paper, an effort is given to explain SMES device and its controllability to mitigate the stability of power grid integrated with wind power generation systems.

关键词： Power fluctuation Power quality Low voltage ride through Superconducting magnetic energy storage Superconductors Wind energy

Short wave stability of homogeneous shear flows with variable topography

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Applied Mathematics and Mechanics(English Edition) 2014年第5期35卷 541-548页

作者：窦华书 v.GANESH Faculty of Mechanical Engineering & Automation Zhejiang Sci-Tech University

For the stability problem of homogeneous shear flows in sea straits of arbitrary cross section, a sufficient condition for stability is derived under the condition of inviscid flow. It is shown that there is a critical wave number, and if the wave number of a normal mode is greater than this critical wave number, the mode is stable.

关键词： hydrodynamic stability shear flow variable bottom sea strait

Generalised tanh-shaped hyperbolic potential: Klein–Gordon equation's bound state solution

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Communications in Theoretical Physics 2023年第7期75卷 22-32页

作者： v H Badalov S v Badalov Institute for Physical Problems Baku State University1148 BakuAzerbaijan Theoretical Materials Physics Paderborn UniversityD-33098 PaderbornGermany Theoretical PhysicsⅦ University of BayreuthD-95440 BayreuthGermany

The development of potential theory heightens the understanding of fundamental interactions in quantum *** this paper,the bound state solution of the modified radial Klein–Gordon equation is presented for generalised tanh-shaped hyperbolic potential from the Nikiforov–Uvarov *** resulting energy eigenvalues and corresponding radial wave functions are expressed in terms of the Jacobi polynomials for arbitrary l *** is also demonstrated that energy eigenvalues strongly correlate with potential parameters for quantum *** particular cases,the generalised tanh-shaped hyperbolic potential and its derived energy eigenvalues exhibit good agreement with the reported ***,the rovibrational energies are calculated for three representative diatomic molecules,namely H2,HCl and *** lowest excitation energies are in perfect agreement with experimental ***,the potential model is displayed to be a viable candidate for concurrently prescribing numerous quantum systems.

关键词： Klein-Gordon equation hyperbolic potential Nikiforov-Uvarov method diatomic molecules

Study Over Thermal State of Gas Turbine Engine Metal-ceramic Rotor Blades and Nozzle Guide vanes Under Thermal Shock and Thermal-cyclic Loading Conditions

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Journal of Thermal Science 2004年第2期13卷 163-166页

作者： A.v.SOUDAREv A.A. SOURYANINOv v.Ya. PODGORETS v.v.GRISHAEv v.Yu. TIKHOPLAv A.S. MOLCHANOv B.v. SOUDAREv Research-Engineering "Ceramic Heat Engines" Center St.Petersburg Russia

To ensure a reliable operation of the 2.5 MW gas turbine engine (GTE- 2.5) with the inlet gas temperature TIT = 1623 K, studies were performed over the thermal state of the nozzle guide vanes and rotor blades with the temperatures, rates and flows of the working media and cooling air simulating all the potential turbine stage operating duties. The steady state and thermal-cyclic tests having been accomplished, there was no visible defect on the rotor blades and the nozzle vanes. Afterwards, they survived the endurance tests at the rated cooling. Therefore, the functionality of the shell thin-wall hybrid nozzle vanes and rotor blades under the variable operating duties of the gas turbine at the 'shock' and 'cyclic' loads of the working media temperature variations has been demonstrated.

关键词： metal-ceramic blades high temperature thermal-cyclic loading

Esterification of levulinic acid to n-butyl levulinate over heteropolyacid supported on acid-treated clay

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Journal of Natural Gas Chemistry 2011年第1期20卷 18-24页

作者： S. Dharne v. v. Bokade Catalysis Division National Chemical Laboratory (CSIR)

Levulinic acid has been identified as a promising green, biomass-derived platform chemical. n-Butyl levulinate is used as an important intermediate having diverse applications. The present work focuses on the synthesis of n-butyl levulinate by esterification of levulinic acid with n-butanol using heteropolyacid （HPA） supported on acid-treated clay montmorillonite （K10）. 20% （w/w） dodecatungestophosphoric acid （DTPA） supported on K10 was found to be the most efficient catalyst with 97% levulinic acid conversion and 100% selectivity towards n-butyl levulinate. Effects of various process parameters were studied to examine the efficacy of 20% （w/w） DTPA/K10 for optimization of the activity.

关键词： levulinic acid n-butanol dodectungestophosphoric acid K10 n-butyl levulinate

Synthesis and photoluminescence studies of Ba(Gd,Ln)B_9O_(16):Eu^(3+)(Ln=La,Y) phosphors for n-Uv LED lighting and display devices

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Journal of Rare Earths 2015年第2期33卷 140-147页

作者： v.v.Rangari S.J.Dhoble Department of Physics RTM Nagpur University

BaGdB9O16：Eu^3＋ and Ba（Gd,Ln）B9O16：Eu^3＋（Ln=La, Y） phosphors were synthesized by solid state diffusion method. The X-ray diffraction, scanning electron microscopy（SEM） and photoluminescence properties were investigated. The as-synthesized BaGdB9O16：Eu^3＋ and Ba（Gd,Ln）B9O16：Eu^3＋（Ln=La, Y） phosphors showed strong red emission under ultraviolet light excitation. By partially substituting Gd^3＋ by La^3＋ and Y^3＋ ions in the host BaGdB9O16：Eu^3＋ materials, the maximum emission intensity was observed for the optimum composition of BaGd0.91La0.8B9O16Eu0.01 phosphor. The experimental results indicated that the Eu doped BaGdB9O16 and Ba（Gd,Ln）B9O16（Ln=La, Y） phosphors were promising red phosphors, which might find potential applications in near-Uv excited LED lighting as well as display devices. Comparison of as-synthesized phosphors with standard phosphor used in CFL（compact fluorescent lamp） was also done. Energy transfer mechanism of Gd^3＋ to Eu^3＋ was also discussed in this paper.

关键词： phosphor solid state diffusion display devices photoluminescence rare earths

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

Influence of Turbulence Intensity and Turbulence Length Scale on the Drag, Lift and Heat Transfer of A Circular Cylinder

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China Ocean Engineering 2017年第3期31卷 357-363页

作者： I.v. Morenko v.L. Fedyaev Institute of Mechanics and Engineering Kazan Science Center Russian Academy of Sciences (IME KazSC RAS) Kazan Russian Federation Kazan National Research Technical University named after A.N. Tupolev - KAI (KNRTU-KAI) Kazan Russian Federation

Influence of the turbulence intensity and turbulence length scale on the hydrodynamic characteristics and heat transfer of a circular cylinder, streamlined by a viscous fluid flow, is numerically studied. We take the Reynolds number of the oncoming flow equal to 4×10^4, the turbulence intensity Tuf and the dimensionless turbulence length scale L-f varying from 1.0% to 40% and from 0.25 to 4.0, respectively. We confirmed that the increase of Tuf leads to the suppression of the periodic vortex shedding from the cylinder surface, and as a result the stationary mode of streamlining is formed. Consequently, with the increasing turbulence intensity directly in front of the cylinder Tu＊, the amplitude of the lift coefficient decreases monotonically. Nevertheless, the time-averaged drag coefficient of the streamlined cylinder decreases at Tu＊〈6.0%, and increases at Tu＊〉9.0%. The dependence of the average Nusselt number on Tu＊ is near-linear, and with the increasing turbulence intensity, the Nusselt number rises. However, the change of the average Nusselt number depending on L-f is non-monotonic and at Lf=l.0, the value reaches its maximum

关键词： hydrodynamics turbulence heat transfer of a circular cylinder