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Journal of Central South University 2024年第6期31卷 1915-1930页

作者： LALCHAND Verma RAMAKANTA Meher Department of Mathematics Sardar Vallabhbhai National Institute of TechnologySurat-395007GujratIndia

This study considers an MHD Jeffery-Hamel nanofluid flow with distinct nanoparticles such as copper,Al_(2)O_(3)and SiO_(2)between two rigid non-parallel plane walls with the fuzzy extension of the generalized dual parametric homotopy *** nanofluids have been formulated to enhance the thermophysical characteristics of fluids,including thermal diffusivity,conductivity,convective heat transfer coefficients and *** to the presence of distinct nanofluids,a change in the value of volume fraction occurs that influences the velocity profiles of the *** short value of nanoparticles volume fraction is considered an uncertain parameter and represented in a triangular fuzzy number range among[0.0,0.1,0.2].A novel generalized dual parametric homotopy algorithm with fuzzy extension is used here to study the fuzzy velocities at various channel ***,the effectiveness of the proposed approach has been demonstrated through a comparison with the available results in the crisp case.

关键词： fuzzy number Jeffery-Hamel(J-H)flow nanofluid homotopy analysis method

Threshold for initiation of motion of unimodal and bimodal sediments

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International Journal of Sediment Research 2013年第1期28卷 24-33页

作者： Shaileshkumar B.PATEL Prem Lal PATEL Prakash Devidas POREY Water Resources Engineering CEDSardar Vallabhbhai National Institute of TechnologySurat-395007India Department of Civil Engineering Sardar Vallabhbhai National Institute of TechnologySurat-395007India sardar vallabhbhai national institute of technology Surat-395007India

Experimental data,obtained from previous studies,on Critical Tractive Stress(CTS) of non-uniform sediments, have been used to verify the adequacy of existing relationships for CTS of non-uniform bimodal *** in view the performance of such relationships,a new relationship for computation of dimensionless CTS of individual size fraction of non-uniform unimodal and bimodal sediments has been proposed in the form of power *** coefficient and exponent of the proposed power law have been empirically correlated with sediment characteristics for available sediment *** proposed relationship has been validated with independent flume and field data to assess their applicability for unimodal and bimodal sediments.

关键词： Bimodal Critical tractive stress Non-uniform sediment Scaling size Unimodal

Spectroscopy of light N~* baryons

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Chinese Physics C 2019年第3期43卷 49-55页

作者： Zalak Shah Keval Gandhi Ajay Kumar Rai Department of Applied Physics Sardar Vallabhbhai National Institute of Technology

We present the masses of N baryons up to 3300 MeV. The radial and orbital excited states are determined using hypercentral constituent quark model with the first-order correction. The obtained masses are compared with the experimental results and other theoretical predictions. The Regge trajectories are also determined in(n, M^2) and(J, M^2) planes. Moreover, the magnetic moments with J^p =(1^+/2,1^-/2) are calculated. We also calculates the Nπ decay width of excited nucleons.

关键词： baryons potential model Regge trajectories

Influence of supports for selective production of 2,5-dimethylfuran via bimetallic copper-cobalt catalyzed 5-hydroxymethylfurfural hydrogenolysis

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Chinese Journal of Catalysis 2017年第4期38卷 699-709页

作者： Sanjay Srivastava G.C.Jadeja Jigisha Parikh Department of Chemical Engineering Sardar Vallabhbhai National Institute of Technology Surat‐395007 Gujarat India

The hydrogenolysis of carbon–oxygen bonds is an important model reaction in upgrading biomass‐derived furanic compounds to transportation *** of these model reactions,namelyconversion of5‐hydroxymethylfurfural(HMF)to the gasoline additive2,5‐dimethylfuran(DMF),isespecially *** this study,bimetallic Cu‐Co catalysts supported on CeO2,ZrO2,and Al2O3were used for the selective hydrogenolysis of HMF to *** structures of the fresh and usedcatalysts were studied using X‐ray diffraction,the Brunauer‐Emmett‐Teller method,transmissionelectron microscopy,temperature‐programmed reduction by H2,temperature‐programmed desorptionof NH3,and CHNS *** structures were correlated with the catalytic ***‐Co/CeO2catalyst produced mainly2,5‐bis(hydroxymethyl)furan via reduction of C=O bonds onlarge Cu *** Cu‐Co/Al2O3catalyst gave the best selectivity for DMF,as a result of a combinationof highly dispersed Cu,mixed copper–cobalt oxides,and suitable weak acidic ***‐Co/ZrO2had low selectivity for DMF and produced a combination of variousover‐hydrogenolysis products,including2,5‐dimethyltetrahydrofuran and5,5‐oxybis(methylene)‐bis(2‐methylfuran),because of the presence of strong acidic *** reaction pathways and effectsof various operating parameters,namely temperature,H2pressure,and time,were studied to enableoptimization of the selective conversion of HMF to DMF over the Cu‐Co/Al2O3catalyst.

关键词： 5‐Hydroxymethylfurfural Hydrogenation Hydrogenolysis Copper‐cobalt Bimetallic Biofuels

Spectroscopy of the ?_(ccb) baryon in the hypercentral constituent quark model

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Chinese Physics C 2018年第5期42卷 25-29页

作者： Zalak Shah Ajay Kumar Rai Department of Applied Physics Sardar Vallabhbhai National Institute of Technology

We extract the mass spectrum of the triply heavy baryon ?ccbusing the hypercentral constituent quark model. The first order correction is also added to the potential term of the Hamiltonian. The radial and orbital exc... 详细信息

关键词： baryons potential model Regge trajectories

Key morphological changes and their linkages with stream power and land-use changes in the Upper Tapi River basin, India

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International Journal of Sediment Research 2021年第5期36卷 602-615页

作者： Resmi Saseendran Ramani Prem Lal Patel Prafulkumar Vasharambhai Timbadiya Department of Civil Engineering Sardar Vallabhbhai National Institute of Technology

Knowledge on spatio-temporal variations in planform, hydraulic geometry, and bed-level variations of alluvial streams is required for planning and development of hydraulic structures and bank protection works. In the current study, a Geographic Information System(GIS) has been used to analyze topographical maps, multi-temporal remotely sensed imagery, and hydrologic and hydraulic data to extract the morphological parameters of the Upper Tapi River, India. The river has been found to have consistent migration towards the northern direction, with erosion/deposition on right/left banks. The river has not experienced any major meander except in the lower reaches of the Upper Tapi Gorge and minor braiding conditions at the location where the river emerges from mountainous topography to the plain *** analyzed river cross sections were found to be depth dominated, and contain large flows within the channel banks. The cross-sections exhibited moderate channel bed adjustments in 1994, 2006, and 2007 wherein excessive sediment flux and stream power were capable of causing morphological changes in the river. High intensity rainfall in the subcatchment resulted in high sediment flux into the river during1994, which was reported to cause significant aggradation at the downgauging station. The analysis of sediment flux into the river in conjunction with decadal land use land cover, revealed that sediment yield from the catchment was reduced during 2000 e2010 due to an increase in water bodies in the form of minor hydraulic structures. The entry of comparatively less sediment laden water into the river, resulted in moderate bed degradation especially in 2006 and 2007 as observed at the downstream station. The methodology applied in the current study is generic in nature and can be applied to other rivers to identify their morphological issues.

关键词： Planform Hydraulic geometry Hatnur reservoir Land use/land cover Sediment yield

A Novel Process of CO_(2) Reduction and CO_(2) Sequestration Through an Innovative Accelerated Carbonation Technique

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Journal of Wuhan University of technology(Materials Science) 2023年第5期38卷 1105-1117页

作者： Akshay Ramesh Bura B Kondraivendhan Department of Civil Engineering Sardar Vallabhbhai National Institute of TechnologySuratGujaratIndia 395007

The efiect of an innovative accelerated carbonation curing technique was evaluated on concrete containing natural zeolite powder and fine aggregate as partial replacement to alleviate the CO_(2) emission up to a certain extent from the concrete production industry and improve sequestration of CO_(2) into the concrete matrix in a stable *** accelerated carbonation curing was accomplished by subjecting the concrete specimens to 0.5 and 0.75 M concentrations of sodium bicarbonate(NaHCO_(3)) solutions up to a curing age of 180 days after the initial 28 days of normal water *** for carbonation depth,pH value,compressive strength,calcium carbonate(CaCO_(3))content,X-ray difiraction,and thermogravimetric(TGA)analyses and Fourier transform infrared spectroscopy(FTIR)were performed to measure the extent of *** obtained results showed an increment in average compressive strength for the zeolite concrete(ZLC)mixes exposed to accelerated carbonation *** ZLC mixes exposed to increasing NaHCO_(3) solution concentration and exposure period exhibited greater carbonation depth and decreased pH at each depth interval indicating higher CO_(2) sequestration within the concrete *** results obtained from the microstructural analysis(XRD,TGA,and FTIR)and CaCO_(3) content measurements confirm that the higher amount of CaCO_(3) formation provides a clear indication of the carbonation enhancement and CO_(2) sequestration within the concrete matrix and in turn contributing to the global warming reduction.

关键词： CO_(2)sequestration accelerated carbonation natural zeolite calcium carbonate

Synthesis,characterization and application of PVA/ionic liquid mixed matrix membranes for pervaporation dehydration of isopropanol

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Chinese Journal of Chemical Engineering 2017年第10期25卷 1402-1411页

作者： Ganesh B.Thorat Smita Gupta Z.V.P.Murthy Department of Chemical Engineering Sardar Vallabhbhai National Institute of Technology Surat 395007 Gujarat India

In this study,polyvinyl alcohol(PVA)–ionic liquid(IL) membranes were prepared for the separation of isopropyl alcohol(IPA)–water azeotropic mixtures by ***-IL composite membranes were prepared by simple solvent evaporation method using four ILs,viz.,1-n-butyl-3-methylimidazolium chloride(BMIMCl),1-hexyl-3-methylimidazolium chloride(HMIMCl),1-hexyl-3-methylimidazolium tetra fluoroborate(HMIMBF4) and 1-octyl-3-methylimidazolium chloride(OMIMCl).Three ILs were used to study the effect of alkyl chain on the pervaporation *** study had focused on the effect feed water concentration from 10%–40%and effect of feed temperature from 50–80°*** properties of all the membranes were studied using Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM) and contact angle *** Arrhenius activation energies for permeation were estimated to be in the range 4–12 kJ·mol-1 from the temperature dependent permeation values.

关键词： Composite membranes Ionic liquids Dehydration Isopropanol Pervaporation

Flow fields around tandem and staggered piers on a mobile bed

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International Journal of Sediment Research 2022年第6期37卷 737-753页

作者： Laxmi Narayana Pasupuleti Prafulkumar Vasharambhai Timbadiya Prem Lal Patel Department of Civil Engineering Sardar Vallabhbhai National Institute of Technology

An experimental investigation on flow fields within the scour holes upstream and downstream of circular piers positioned in tandem and staggered arrangements is reported and compared with isolated piers on mobile beds with uniform sediment. The instantaneous bed elevations and instantaneous three dimensional(3 D) velocities were measured using a 5 MHz Ultrasonic Ranging system and 16 MHz micro down looking acoustic Doppler velocimeter, respectively. The velocity and flow depth were measured at different locations under near equilibrium bed scour conditions. The measured 3 D velocities were processed for the computation of flow parameters, such as velocity fields, streamline patterns, vorticity fields, and circulation. Furthermore, turbulence intensities, turbulent kinetic energy, Reynolds shear stresses, and bed shear stresses around the piers for all three pier configurations were computed from the detrended velocity signals to identify significant differences in the flow parameters and turbulence in the tandem and staggered pier arrangements as compared to those for an isolated pier. A recirculation zone was found near the bed in front of the rear pier in the tandem case from the streamline *** vortices in the bi-vortex system were observed to be opposite to each other in the gap between the three piers in the staggered case. A strong secondary vortex also was observed apart from the primary vortex at the foot of the pier(θ = 0°) in all the three configurations. The strength of the horseshoe vortex(combination of primary and secondary vortices) was found to be higher at the front piers of the staggered arrangement as compared to those of the tandem piers, followed by the isolated pier. The bed shear stresses were found to be higher for the staggered piers than for the tandem piers in the direction of flow(θ = 0°). However, a 50% reduction in the bed shear stresses was observed behind the tandem piers at θ = 180°. The study reported in this paper provides

关键词： Staggered piers Tandem piers Scour hole Vorticity Circulation Bed level variation

Experimental investigation on the effects of process parameters of GMAW and transient thermal analysis of AISI321 steel

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Advances in Manufacturing 2013年第4期1卷 362-377页

作者： A.G.Kamble R.Venkata Rao Department of Mechanical Engineering Sardar Vallabhbhai National Institute of Technology

Gas metal arc welding （GMAW） develops an arc by controlling the metal from the wire rod and the input pro- cess parameters. The deposited metal forms a weld bead and the mechanical properties depend upon the quality of the weld bead. Proper control of the process parameters which affect the bead geometry, the microstructures of the weldments and the mechanical properties like hardness, is necessary. This experimental study aims at developing mathematical models for bead height （HB）, bead width （WB） and bead penetration （PB） and investigating the effects of four process parameters viz： welding voltage, welding speed, wire feed rate and gas flow rate on bead geometry, hardness and microstructure of AISI321 steel with 10 mm thickness. The transient thermal analysis shows temperature and residual stress distributions at different conduction and convection conditions.

关键词： Gas metalMathematical modelingthermal analysisarc welding (GMAW)Microstructure ~ Transient