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High-temperature deformation behaviour of duplex stainless steel with hard boronised layer

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Journal of Iron and Steel Research International 2021年第2期28卷 244-253页

作者： n.m.Sultan I.Jauhari R.Saidan m.F.m.Sabri Department of mechanical Engineering Faculty of EngineeringUniversity MalayaKuala Lumpur 50603Malaysia

In order to understand the high-temperature deformation behaviour of alloy having hard surface layer,thermo-mechanically treated duplex stainless steel(DSS)is boronised for 0.75-6 h at 1223 K and subsequently deformed under compression mode at the same temperature under strain rate condition of 1×10^(-3),2×10^(-4) and 6×10^(-5) s^(-1) until strain of *** substrate microstructure is almost isotropic with grain size after boronising with layer thickness between 1.61 and 2.74μm.X-ray diffraction results confirm the formation of boride on DSS *** surface hardness of DSS increases from 387 to 1000-2400 HV after *** boronised layer with thickness of 20-40μm is formed at DSS *** results show that the flow stress of the deformation increases with the strain rate and boronising *** the boronised samples,the flow stress range is between 5 and 89 *** determine the actual effect of the boronised layer on the flow stress,the results are also compared with those from un-boronised samples having similar *** results suggest that at a constant grain size,even with the hardest layer,the effect of hard surface layer on the flow stress almost could be negligible when the deformation rate is slow,but at faster deformation rate,even in the layer with the least hardness,the flow stress shows a significant *** is also observed that the hard boride surface disintegration could be avoided at a sufficiently low deformation flow stress that could be attributed to superplasticity.

关键词： High-temperature deformation Superplasticity Duplex stainless steel Hard boride layer Surface integrity Grain size effect Strain rate effect

Water Resource management in the Intermountain Izeh Plain,Southwest of Iran

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Journal of mountain Science 2009年第1期6卷 25-41页

作者： Kalantari.n Pawar.n.J Keshavarzi.m.R Geology Department Shahid Chamran UniversityAhvazIran Geology Department University of PunePune-411 007India

Ever growing demand for water for agricultural activities in the Izeh Plain has enhanced the use of groundwater. Due to enormous groundwater abstraction since 1985, the overall static water level has receded by more than 5 meters reflecting that the aquifer is under stress condition. As a result, interest is focused on application of artificial recharge as an option for groundwater management to augment water supply in this area. Therefore, in the present investigations, suitable sites for artificial recharge were selected by an integrated surface and sub-surface assessment of the area. On the basis of the data collected from four target points, it was realized that the selected sites for artificial recharge could not meet water demand of the area. In this study attention was also paid to utilization of the existing miangran Lake water as an alternative to combat water shortage for irrigation. The study further indicated that the available miangran Lake water could be used for irrigation of the reclaimed agricultural land and enabling to convert 20o0 hectares of rain-fed land into irrigation. The total cost to utilize lake water is US$ 2,756,729 and it was estimated that the project could recoup the investment within 5 years which is quite reasonable in this water scarcity prone area.

关键词： Artificial recharge stream miangranLake groundwater Izeh Plain

Jacobian-free newton-Krylov subspace method with wavelet-based preconditioner for analysis of transient elastohydrodynamic lubrication problems with surface asperities

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Applied mathematics and mechanics(English Edition) 2020年第6期41卷 881-898页

作者： n.m.BUJURKE m.H.KAnTLI Department of mathematics Karnatak UniversityDharwad 580003India Department of mathematics Biluru Gurubasava Mahaswamiji Institute of TechnologyMudhol 587313India

This paper presents an investigation into the effect of surface asperities on the over-rolling of bearing surfaces in transient elastohydrodynamic lubrication(EHL) line contact. The governing equations are discretized by the finite difference method. The resulting nonlinear system of algebraic equations is solved by the Jacobian-free newtongeneralized minimal residual(GmRES) from the Krylov subspace method(KSm). The acceleration of the GmRES iteration is accomplished by a wavelet-based *** profiles of the lubricant pressure and film thickness are obtained at each time step when the indented surface moves through the contact region. The prediction of pressure as a function of time provides an insight into the understanding of fatigue life of *** analysis confirms the need for the time-dependent approach of EHL problems with surface asperities. This method requires less storage and yields an accurate solution with much coarser grids. It is stable, efficient, allows a larger time step, and covers a wide range of parameters of interest.

关键词： transient elastohydrodynamic lubrication(EHL) surface roughness bearing newton-Krylov method generalized minimal residual(GmRES) wavelet preconditioner

A new player in the beneficial effects of exercise on the aged brain

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Signal Transduction and Targeted Therapy 2020年第1期5卷 901-902页

作者： m.Llorens-martín Department of molecular neuropathology Centro de Biología Molecular“Severo Ochoa”CBMSOCSIC-UAMMadridSpain Center for networked Biomedical Research on neurodegenerative Diseases(CIBERnED) MadridSpain Department of molecular Biology Faculty of SciencesUniversidad Autónoma de MadridMadridSpain

In a recent article in Science,Horowitz et *** glycosylphosphatidylinositol(GPI)-degrading enzyme Gpld1 as the most critical player in the blood that can transfer the effects of exercise on adult neurogenesis and cognition to sedentary aged *** also demonstrate the importance of this liver-to-brain axis in ameliorating age-related regenerative and cognitive impairments.

关键词： tar player critical

Convective heat transfer from two rotating circular cylinders in tandem arrangement by using lattice Boltzmann method

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Applied mathematics and mechanics(English Edition) 2012年第4期33卷 427-444页

作者： H. nEmATI m. FARHADI K. SEDIGHI m. m. PIROUZ n. n. ABATARI Faculty of mechanical Engineering Babol Noshirvani University of Technology

The numerical investigation of the two-dimensional laminar flow past two ro- tating circular cylinders in the tandem arrangement is conducted by the lattice Boltzmann method. The numerical strategy is used for dealing with curved and moving boundaries of the second-order accuracy for velocity and temperature fields. The effects of various rotational speed ratios and gap spacing are studied with the Reynolds number of 100 and the Prandtl number of 0.71. A varied range of rotational speed ratios are investigated for four different gap spacing, i.e., 3.0, 1.5, 0.7, and 0.2. The results show that, for the first cylinder, the lift and drag coefficients for large gap spacing are similar to those for a single cylinder; for the second cylinder, the lift coefficient descends with the increase in the angular velocity for all gap spacing, while the drag coefficient ascends except for the gap spacing of 3.0. The results of the averaged periodic nusselt number on the surface of the cylinders show that, for small distances between the cylinders and low angular velocities, conduction is a dominant mechanism of heat transfer, but for large distances and high angular velocities, convection is the main mechanism of heat transfer.

关键词： lattice Boltzmann method rotating circular cylinder laminar flow curvedand moving boundary

Photon interaction with semiconductor and scintillation detectors

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nuclear Science and Techniques 2016年第3期27卷 159-170页

作者： v.p.singh n.m.badiger Department of Physics Karnatak UniversityDharwad 580003India

mass attenuation coefficients,effective atomic numbers,and electron densities for semiconductor and scintillation detectors have been calculated in the photon energy range 1 keV-100 *** interaction parameters have been found to vary with detector composition and the photon *** variation in the parameters with energy is shown graphically for all the partial photon interaction *** effective atomic numbers of the detector were compared with the ZXCOm program,and the results were found to be *** of semiconductor and scintillation detectors are presented in terms of effective atomic *** study should be useful for comparing the detector performance in terms of gamma spectroscopy,radiation sensitivity,radiation measurement,and radiation *** results of the present investigation should stimulate research work for gamma spectroscopy and radiation measuring materials.

关键词：相互作用参数闪烁探测器半导体光子有效原子序数光谱探测器质量衰减系数能量变化

Effect of deposition conditions on the physical properties of Sn_xS_y thin films prepared by the spray pyrolysis technique

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Journal of Semiconductors 2011年第11期32卷 31-38页

作者： m.R.Fadavieslam n.Shahtahmasebi m.Rezaee-Roknabadi m.m.Bagheri-mohagheghi nanotechnology Research Center Department of PhysicsFaculty of Basic SciencesFerdowsi University of MashhadMashhadIran School of Physics Damghan University

Tin sulfide thin films （Snx Sy） with an atomic ratio of y/x = 0.5 have been deposited on a glass substrate by spray pyrolysis. The effects of deposition parameters, such as spray solution rate （R）, substrate temperature （Ts） and film thickness （t）, on the structural, optical, thermo-electrical and photoconductivity related properties of the films have been studied. The precursor solution was prepared by dissolving tin chloride （SnC14, 5H2O） and thiourea in propanol, and SnxSy thin film was prepared with a mole ratio of y/x = 0.5. The prepared films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEm） and UV-vis spectroscopy. It is indicated that the XRD patterns of SnxSy films have amorphous and polycrystalline structures and the size of the grains has been changed from 7 to 16 nm. The optical gap of SnxSy thin films is determined to be about 2.41 to 3.08 eV by a plot of the variation of （αhv）2 versus h v related to the change of deposition conditions. The thermoelectric and photo-conductivity measurement results for the films show that these properties are depend considerably on the deposition parameters.

关键词： thin film tin sulfide spray pyrolysis photoconductivity

Antimonene-based saturable absorber for a soliton mode-locked and Q-switched fiber laser in the 2 μm wavelength region

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Chinese Physics B 2023年第6期32卷 259-269页

作者： H Ahmad B nizamani m Z Samion n Yusoff m F Ismail Photonics Research Centre Universiti Malaya50603 Kuala LumpurMalaysia Physics Department Faculty of ScienceUniversiti Malaya50603 Kuala LumpurMalaysia Distinguished Visiting Professor Universiti Kuala Lumpur British Malaysian Institute(UniKL BMI)Batu 8Jln Sungai Pusu53100SelangorMalaysia

We demonstrate antimonene as a saturable absorber(SA) to generate an ultrafast mode-locked and Q-switched laser in the 2 μm wavelength region. The two antimonene-based SAs were prepared and inserted separately in a thulium–holmiumdoped fiber laser to produce the pulsed laser. Antimonene was coated onto a tapered fiber to generate soliton mode-locked pulses and used in thin-film form for the generation of Q-switched pulses. The mode-locking was stable within a pump power of 267 m W–511 m W, and the laser operated at a central wavelength of 1897.4 nm. The mode-locked laser had a pulse width of 1.3 ps and a repetition rate of 12.6 mHz, with a signal-to-noise ratio of 64 d B. Q-switched laser operation was stable at a wavelength of 1890.1 nm within a pump power of 312 m W–381 m W. With the increase in pump power from 312 m W to 381 m W, the repetition rate increased to a maximum of 56.63 k Hz and the pulse width decreased to a minimum value of 2.85 μs. Wide-range tunability of the Q-switched laser was also realized within the wavelength range of1882 nm–1936 nm.

关键词： mode-locking Q-switched fiber laser optical saturable absorber

metal-enhanced fluorescence of graphene oxide by palladium nanoparticles in the blue-green part of the spectrum

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Chinese Physics B 2016年第11期25卷 576-583页

作者： A Omidvar m R Rashidian Vaziri B Jaleh n Partovi Shabestari m noroozi Department of Physics Bu-Ali Sina University Laser and Optics Research School NSTRI Tehran Iran Center for Research and Development of Petroleum Technologies at Kermanshah Research Institute of Petroleum Industry (RIPI)

Graphene oxide（GO） has a wide fluorescence bandwidth,which makes it a prospective candidate for numerous *** many of these applications,the fluorescence yield of GO should be further *** sp2-hybridized carbons in GO confine the π-*** recombination of electron-hole pairs in such sp2 clusters is the source of fluorescence in this *** nanoparticles are good catalysts for sp2 bond *** report on the preparation of GO,palladium nanoparticles and their nanocomposites in two different *** is shown that palladium nanoparticles can considerably enhance the intrinsic fluorescence of GO in the blue-green part of the visible light *** enhancement has been attributed to the catalytic role of palladium nanoparticles in increasing the number of sp2 bonds of GO with the molecules of the surrounding *** is shown that palladium nanoparticles could be the nanoparticle of choice for fluorescence enhancement of GO because of their catalytic role in sp2 bond formation.

关键词： palladium formations considerably bonds Palladium attributed numerous Fluorescence visible bandwidth