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Assessment of soil erosion in the Irga watershed on the eastern edge of the Chota Nagpur Plateau,India

Regional Sustainability 2024年第1期5卷 54-68页

作者： Ratan PAL Buddhadev HEMBRAM Narayan chandra JANA Department of Geography the University of BurdwanWest Bengal-713104India

Human activities to improve the quality of life have accelerated the natural rate of soil *** turn,these natural disasters have taken a great impact on *** activities,particularly the conversion of vegetated land into agricultural land and built-up area,stand out as primary contributors to soil *** present study investigated the risk of soil erosion in the Irga watershed located on the eastern fringe of the Chota Nagpur Plateau in Jharkhand,India,which is dominated by sandy loam and sandy clay loam soil with low soil organic carbon(SOC)*** study used the Revised Universal Soil Loss Equation(RUSLE)and Geographical Information System(GIS)technique to determine the rate of soil *** five parameters(rainfall-runoff erosivity(R)factor,soil erodibility(K)factor,slope length and steepness(LS)factor,cover-management(C)factor,and support practice(P)factor)of the RUSLE were applied to present a more accurate distribution characteristic of soil erosion in the Irga *** result shows that the R factor is positively correlated with rainfall and follows the same distribution pattern as the *** K factor values in the northern part of the study area are relatively low,while they are relatively high in the southern *** mean value of the LS factor is 2.74,which is low due to the flat terrain of the Irga *** is a negative linear correlation between Normalized Difference Vegetation Index(NDVI)and the C factor,and the high values of the C factor are observed in places with low *** mean value of the P factor is 0.210,with a range from 0.000 to *** calculating all parameters,we obtained the average soil erosion rate of 1.43 t/(hm^(2)•a),with the highest rate reaching as high as 32.71 t/(hm^(2)•a).therefore,the study area faces a low risk of soil ***,preventative measures are essential to avoid future damage to productive and constructive activities caused by soil *** study also ident

关键词： Soil erosion Soil organic carbon Rainfall-runoff erosivity factor Soil erodibility factor Slope length and steepness factor Cover-management factor Support practice factor Irga watershed

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Hydrogen absorption properties of amorphous(Ni0.6Nb0.4-ytay)100-xZrx membranes

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Progress in Natural Science:Materials International 2017年第1期27卷 126-131页

作者： O.Palumbo F.trequattrini N.Pal M.Hulyalkar S.Sarker D.chandra t.Flanagan M.Dolan A.Paolone CNR-ISC U.O.S. La Sapienza Department of Physics Sapienza University of Rome Department of Chemical and Materials Engineering University of Nevada Department of Chemistry University of Vermont CSIRO QCAT Energy 1 Technology CourtPullenvale

Ni based amorphous materials have great potential as hydrogen purification membranes. In the present work the melt spun(Ni0.6Nb0.4-ytay)100-xZrxwith y=0, 0.1 and x=20, 30 was studied. the result of X-ray diffraction spectra of the ribbons showed an amorphous nature of the alloys. Heating these ribbons below t tmosphere（1-10 bar）, the amorphous structure was retained. the crystallization process was characterized by differential thermal analysis and the activation energy of such process was obtained. the hydrogen absorption properties of the samples in their amorphous state were studied by the volumetric method,and the results showed that the addition of ta did not significantly influence the absorption properties, a clear change of the hydrogen solubility was observed with the variation of the Zr content. the values of the hydrogenation enthalpy changed from37 k J/mol for x=30 to9k J/mol for x=20. the analysis of the volumetric data provides the indications about the hydrogen occupation sites during hydrogenation, suggesting that at the beginning of the absorption process the deepest energy levels are occupied, while only shallower energy levels are available at higher hydrogen content, with the available interstitial sites forming a continuum of energy levels.

关键词： Amorphous Ni based alloy ribbons High temperature X-ray diffraction DtA Activation energy Crystallization temperature Hydrogen solubility

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the redshift distribution of BL Lacs and FSRQs

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Research in Astronomy and Astrophysics 2019年第1期19卷 131-140页

作者： David Garofalo chandra B.Singh Dylan t.Walsh Damian J.Christian Andrew M.Jones Alexa Zack Brandt Webster Matthew I.Kim Department of Physics Kennesaw State University the Raymond and Beverly Sackler School of Physics and Astronomy Tel Aviv University Department of Physics & Astronomy California State University Boise State University Computational Science & Engineering

Flat spectrum radio quasars(FSRQs) and BL Lacertae objects(BL Lacs) are powerful jet producing active galactic nuclei associated with supermassive black holes accreting at high and low Eddington rates, respectively. Based on the Millennium Simulation, Gardner & Done have predicted their redshift distribution by appealing to ideas from the spin paradigm in a way that exposes a need for a deeper discussion on three interrelated issues:(1) an overprediction of BL Lacs compared to FSRQs;(2) a difference in FSRQ and BL Lac distributions;(3) a need for powerful but different jets at separated cosmic times. Beginning with Gardner & Done's determination of Fermi observable FSRQs based on the distribution of thermal accretion across cosmic time from the Millennium Simulation, we connect FSRQs to BL Lacs by way of the gap paradigm for black hole accretion and jet formation to address the above issues in a unified way. We identify a physical constraint in the paradigm for the numbers of BL Lacs that naturally leads to separate peaks in time for different albeit powerful jets. In addition, we both identify as puzzling and ascribe physical significance to a tail end in the BL Lac curve versus redshift that is unseen in the redshift distribution for FSRQs.

关键词： black hole physics BL Lacertae objects:general galaxies:ets gamma-rays:galaxies

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Optimization of process parameters of aluminum alloy AA 2014-t6 friction stir welds by response surface methodology

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Defence technology（防务技术） 2015年第3期11卷 209-219页

作者： Ramanjaneyulu KADAGANCHI Madhusudhan reddy GANKIDI Hina GOKHALE Mahatma Gandhi Institute of technology Defence Metallurgical Research Laboratory

the heat treatable aluminum-copper alloy AA2014 finds wide application in the aerospace and defence industry due to its high strength-toweight ratio and good ductility. Friction stir welding(FSW) process, an emerging solid state joining process, is suitable for joining this alloy compared to fusion welding processes. this work presents the formulation of a mathematical model with process parameters and tool geometry to predict the responses of friction stir welds of AA 2014-t6 aluminum alloy, viz yield strength, tensile strength and ductility. the most influential process parameters considered are spindle speed, welding speed, tilt angle and tool pin profile. A four-factor, five-level central composite design was used and a response surface methodology(RSM) was employed to develop the regression models to predict the *** mechanical properties, such as yield strength(YS), ultimate tensile strength(UtS) and percentage elongation(%El), are considered as responses. Method of analysis of variance was used to determine the important process parameters that affect the responses. Validation trials were carried out to validate these results. these results indicate that the friction stir welds of AA 2014-t6 aluminum alloy welded with hexagonal tool pin profile have the highest tensile strength and elongation, whereas the joints fabricated with conical tool pin profile have the lowest tensile strength and elongation.

关键词：焊接工艺参数搅拌摩擦焊铝合金焊接响应面分析法抗拉强度优化焊接接头屈服强度

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Experimental Investigation on the Performance of Armour Grade Q&t Steel Joints Fabricated by Flux Cored Arc Welding with Low Hydrogen Ferritic Consumables

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Journal of Materials Science & technology 2009年第5期25卷 583-591页

作者： G.Magudeeswaran V.Balasubramanian G.Madhusudhan reddy G.Gopalakrishnan Metal Joining Research Center(MJRC) Sri Ramakrishna Engineering CollegeN.G.G.O Colony-Post Centre for Materials Joining&Research(CEMAJOR) Department of Manufacturing EngineeringAnnamalai University Scientist-F Metal Joining SectionDefence Metallurgical Research Laboratory(DMRL)Kanchanbagh(P.O)

Quenched and tempered （Q＆t） steels are widely used in the construction of military vehicles due to its high strength to weight ratio and high hardness. these steels are prone to hydrogen induced cracking （HIC） and softening in the heat affected zone （HAZ） after welding. the use of austenitic stainless steel （ASS） consumables to weld the above steel was the only available remedy to avoid HIC because of higher solubility for hydrogen in austenitic phase. Recent studies revealed that low hydrogen ferritic （LHF） steel consumables can also be used to weld Q＆t steels, which can give very low hydrogen levels in the weld deposits and required resistance against cold cracking. Hence, in this investigation an attempt has been made to study the performance of armour grade Q＆t steel joints fabricated by flux cored arc welding with LHF steel consumables. two different consumables namely （i） austenitic stainless steel and （ii） low hydrogen ferritic steel have been used to fabricate the joints by flux cored arc welding （FCAW） process. the joints fabricated by LHF consumable exhibited superior transverse tensile properties due to the presence of ferrite microstructure in weld metal. the joints fabricated by ASS consumable showed higher impact toughness due to the presence of austenitic phase in weld metal microstructure. the HAZ softening in coarse grain heat affected zone （CGHAZ） is less in the joints fabricated using LHF consumable due to the lower heat input involved during fabrication compared to the joints fabricated using ASS consumables.

关键词： Quenched and tempered steel Flux cored arc welding process Low hydrogen ferritic steel tensile properties

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Microstructure and mechanical properties of friction stir welded AA7075-t651 aluminum alloy thick plates

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transactions of Nonferrous Metals Society of China 2015年第6期25卷 1770-1778页

作者： t.SRINIVASA RAO G.MADHUSUDHAN reddy S.R.KOtESWARA RAO Department of Mechanical Engineering Tagore Engineering College Metal Joining Group Defense Metallurgical Research Laboratory Department of Mechanical Engineering SSN College of Engineering

Friction stir butt welding of AA7075-t651 plates with thicknesses of 10 and 16 mm was investigated. Defect-free, full- penetration welds were obtained after careful process parameter selection. While the nuggets in both welds exhibited very fine reerystallized grains, and finer grains were observed in welds made on 10 mm thick plates. Microhardness surveys revealed that significant loss in hardness occurs in the heat-affected zone. the reduction in hardness due to the welding process is higher in the case of welds made on 16 mm thick plates. Welds made on 10 mm thick plates exhibited superior tensile properties compared with those made on 16 mm thick plates. Fracture during tensile test occurred in the heat-affected zone in both cases. tEM images of specimens revealed that the heat-affected zone consisted of widened precipitate-free zones along grain boundaries and partial dissolution of precipitates in the grain interiors. It is concluded that defect-free single pass welds can be made on AA7075-t651 thick plates using friction stir welding and the welds made on 10 mm thick plates exhibit high joint efficiency.

关键词： AA7075-t651 aluminum alloy friction stir welding microstructure mechanical properties

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Solar thermal Energy Generation Potential in Gujarat and tamil Nadu States, India

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Energy and Power Engineering 2015年第13期7卷 591-603页

作者： C. Nagarjuna reddy t. Harinarayana Gujarat Energy Research and Management Institute Gandhinagar India

Government of India has come out with an ambitious target of 100 GW of using solar energy alone by the year 2022. to reach this target, innovative ideas are required to use the solar energy more effectively. For solar electricity generation, mainly two types of technologies are presently in use, namely, solar PV and solar thermal. Being a tropical country, India has large solar PV and solar thermal energy. More research is required on economic aspects to make the solar thermal competitive to solar PV. towards this direction, in our present study we have simulated a solar thermal power plant using Parabolic trough Collector (PtC) technology and normalized with 1 MW solar thermal power plant at Gurgaon near New Delhi. through simulation, we have extended our study and computed the electricity generation possible at different locations of India. For this purpose with 1? × 1?spacing, computations have been carried out at 296 locations. the work is further extended for more detailed study at two representative states, namely, Gujarat and tamil Nadu. In these two states, closer data points with 0.25? × 0.25? spacing have been considered at 273 locations for Gujarat and 197 locations for tamil Nadu. Our results indicate a large potential of electricity generation using solar thermal energy in southern states of India, namely, tamil Nadu, Karnataka, Kerala, southern and western part of Andhra Pradesh and eastern part of Maharashtra. Good potential has also been observed in eastern parts of Gujarat and parts of Madhya Pradesh and eastern part of Rajasthan. the annual potential ranges from 1800 MWh to as much as 2600 MWh. Major parts of northern states, for example Uttar Pradesh, Bihar, West Bengal, Punjab, Jammu and Kashmir have medium range potential. Here, the annual potential ranges from 1000 to 1500 MWh. Poor range of potential is observed towards eastern parts of India and north eastern states. Here, the electricity generation potential ranges from 600 to 1200 MWh. Our

关键词： Solar thermal Parabolic trough Energy India Gujarat tamil Nadu Modelling

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Flexible Covalent Organic Frameworks:Design,Synthesis,and Applications

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CCS Chemistry 2024年第4期6卷 856-881页

作者： Chunqing Ji Chengjun Kang Bidhan chandra Patra Dan Zhao Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117585

Structural flexibility is an intriguing characteristic observed in materials that endows them with dynamic properties,allowing for intelligent adaptation and deformation in response to varying *** organic frameworks(COFs),a promising class of crystalline porous polymers,have garnered significant attention due to their unique features,including well-ordered,predesignable,and tunable structures,as well as their light-weighted nature and high thermal/chemical *** flexibility into COFs offers a captivating pathway for developing advanced materials with dynamic properties and versatile *** flexible COF field is currently experiencing rapid expansion,and there is a growing need for systematic review articles that offer a comprehensive overview of the developments in this *** this mini-review,we delve into the factors that contribute to structural flexibility in COFs from the point of structural *** summarize and categorize various modes of achieving flexibility across different dimensions,and discuss the potential applications of flexible COFs in vapor/gas adsorption,sensing,and smart membrane separations;further,we highlight their prospects and future research advancement.

关键词： covalent organic frameworks framework flexibility inducing factors flexibility modes smart materials

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Effect of metal fluorides on chromium ions doped bismuth borate glasses for optical applications

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Chinese Physics B 2019年第3期28卷 366-372页

作者： L Haritha K chandra Sekhar R Nagaraju G Ramadevudu Vasanth G Sathe Md.Shareefuddin Department of Physics Telangana University Department of Physics Osmania University Department of Physics Vasavi College of Engineering UGC-DAE Consortium of Scientific Research

Fluoride based glasses with composition CaF_2-ZnF_2-Bi_2 O_3-B_2 O_3 doped with chromium ions have been investigated using physical, optical, electron paramagnetic resonance(EPR), Fourier-transform infrared spectroscopy(FtIR), and Raman studies. the amorphous nature of samples was confirmed from x-ray diffraction spectra. the density is evaluated from the Archimedes principle and the values of optical band gap and Urbach energy values were evaluated from the optical absorption spectra. thus, molar volume, refractive index, etc., were also evaluated. the observed decrease in density and the optical band gap with CaF2 is explained using the crystalline density of metal fluorides and the ionicity of fluorine ions,respectively. the three peaks near 450 nm, 606 nm, and 720 nm, which are shown in the absorption spectra, are accredited to ~4 A)(2 g) → ~4 t_(1 g), ~4 A_(2 g)→ ~4 t_(2 g), ~4 A_(2 g)→~2 E transitions, respectively. Resonance signals at g≈ 4.82 and g≈ 1.99 were observed in EPR spectra which are assigned. FtIR and Raman analysis were carried out to examine the impact of metal fluorides on the structure of bismuth borate glasses.

关键词： glasses x-ray diffraction electron paramagnetic resonance Fourier-transform infrared spectroscopy(FtIR) Raman spectra

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Structural and optical studies on PVA capped SnS films grown by chemical bath deposition for solar cell application

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Journal of Semiconductors 2019年第5期40卷 17-26页

作者： P Mallika Bramaramba Devi G.Phaneendra reddy K.t.Ramakrishna reddy Solar Energy Laboratory Department of Physics Sri Venkateswara University

tin monosulphide(SnS) thin films capped by PVA have been successfully deposited on glass substrates for cost effective photovoltaic device applications by a simple and low-cost wet chemical process, chemical bath deposition(CBD) at different bath temperatures varying in the range, 50–80 °C. X–ray diffraction analysis showed that the deposited films were polycrystalline in nature, showing orthorhombic structure with an intense peak corresponding to(040) plane of SnS. these observations were further confirmed by Raman analysis. FtIR spectra showed the absorption bands which corresponds to PVA in addition to *** scanning electron microscopy and atomic force microscopy studies revealed that the deposited SnS films were uniform and nanostructured with an average particle size of 4.9 to 7.6 nm. the optical investigations showed that the layers were highly absorbing with the optical absorption coefficient ～10~5 cm^(-1). A decrease in optical band gap from 1.92 to 1.55 eV with an increase of bath temperature was observed. the observed band gap values were higher than the bulk value of 1.3 eV, which might be due to quantum confinement effect. the optical band gap values were also used to calculate particle size and the results are discussed.

关键词： chemical bath deposition polyvinyl alcohol capping agent SnS thin films structural properties optical properties

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