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Anisotropic strange quark star in Finch-Skea geometry and its maximum mass for non-zero strange quark mass(m_(s)≠0)

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Chinese Physics C 2023年第5期47卷 195-210页

作者： b.das K.b.Goswami A.Saha P.K.Chattopadhyay Department of Physics Coochbehar Panchanan Barma UniversityVivekananda StreetCoochbehar 736101West BengalIndia Department of Physics Alipurduar CollegeAlipurduar 736122West BengalIndia

A class of relativistic astrophysical compact objects is analyzed in the modified Finch-Skea geometry described by the MIT bag model equation of state of interior matter,p=1/3(ρ-4b),where b is known as the bag constant.b plays an important role in determining the physical features and structure of strange *** consider the finite mass of the strange quark(m_(s)≠0) and study its effects on the stability of quark matter inside a *** note that the inclusion of strange quark mass affects the gross properties of the stellar configuration,such as maximum mass,surface red-shift,and the radius of strange quark *** apply our model physically,we consider three compact objects,namely,(ⅰ) VELA X-1,(ⅱ) 4U 1820-30,and(ⅲ) PSR J 1903+327,which are thought to be strange *** range of b is restricted from 57.55 to bstable(MeV/fm3),for which strange matter might be stable relative to iron(^(56)Fe).However,we also observe that metastable and unstable strange matter depend on b and *** energy conditions hold well in this *** in terms of the Lagrangian perturbation of radial pressure is studied in this paper.

关键词： compact star strange star anisotropy MIT EoS strange quark mass

Anisotropic strange quark star in Finch-Skea geometry and its maximum mass for non-zero strange quark mass(m≠ 0)

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Chinese Physics C 2023年 201-216页

作者： b.das K.b.Goswami A.Saha P.K.Chattopadhyay Department of Physics Coochbehar Panchanan Barma University Department of Physics Alipurduar College

A class of relativistic astrophysical compact objects is analyzed in the modified Finch-Skea geometry de-scribed by the MIT bag model equation of state of interior matter, p =1/3(ρ-4b), where b is known as the bag con-stant. b plays an important role in determining the physical features and structure of strange stars. We consider the finite mass of the strange quark( ms 0) and study its effects on the stability of quark matter inside a star. We note that the inclusion of strange quark mass affects the gross properties of the stellar configuration, such as maximum mass, surface red-shift, and the radius of strange quark stars. To apply our model physically, we consider three compact objects, namely,(i) VELA X-1,(ii) 4U 1820-30, and(iii) PSR J 1903+327, which are thought to be strange stars. The range of b is restricted from 57.55 to bstable( MeV/fm3), for which strange matter might be stable relative to iron(56Fe). However, we also observe that metastable and unstable strange matter depend on b and ms. All energy conditions hold well in this approach. Stability in terms of the Lagrangian perturbation of radial pressure is studied in this paper.

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Ultrasonic vibration-assisted cutting of titanium alloys:A state-of-the-art review

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Chinese Journal of Aeronautics 2025年第1期38卷 3-42页

作者： Ahmar KHAN Xin WANG biao ZHAO Wenfeng DING Muhammad JAMIL Aqib Mashood KHAN Syed Hammad ALI Sadam HUSSAIN Jiong ZHANG Raj das National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Mechanical Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Centre for Additive Manufacturing School of EngineeringAerospace Engineering and AviationRMIT UniversityVictoria 3083Australia

The remarkable ability of titanium alloys to preserve their superior physical and chemical characteristics when subjected to extreme conditions significantly enhances their importance in the aerospace,military,and medical ***,conventional machining of titanium alloys leads to elevated tool wear,development of surface defects,and reduced machining efficiency due to their low heat conductivity,and chemical *** issues can be somewhat counteracted by integrating ultrasonic vibration in the conventional machining of titanium alloys and also enhance *** review article offers a holistic evaluation of the influence of ultrasonic vibration-assisted milling and turning on cutting forces,temperature,tool wear,and surface integrity,encompassing surface morphology,surface roughness,surface residual stress,surface hardness,and surface tribological properties during titanium alloys ***,it investigates the sustainability aspect that has not been previously *** on the performance of ultrasonic-assisted cutting revealed several advantages,including decreased cutting forces and cutting temperature,improved tool life,and a better-machined surface during ***,the sustainability factor is improved due to minimized energy consumption and residual *** conclusion,the key challenges and future prospects in the ultrasonic-assisted cutting of titanium alloys are also *** review article provides beneficial knowledge for manufactur-ers and researchers regarding ultrasonic vibration-assisted cutting of titanium alloy and will play an important role in achieving sustainability in the industry.

关键词： Ultrasonic vibration-assisted cutting Titanium alloys Material removal mechanism Machinability Sustainability

Optimization of flotation variables for the recovery of hematite particles from bHQ ore

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International Journal of Minerals,Metallurgy and Materials 2013年第7期20卷 605-611页

作者： Swagat S. Rath Hrushikesh Sahoo b. das CSIR-Institute of Minerals and Materials Technology Bhubaneswar 751 013 India

The technology for beneficiation of banded iron ores containing low iron value is a challenging task due to increasing demand of quality iron ore in India. A flotation process has been developed to treat one such ore, namely banded hematite quartzite （bHQ） containing 41.8wt% Fe and 41.5wt% SiO2,by using oleic acid, methyl isobutyl carbinol （MIbC）, and sodium silicate as the collector, frother, and dispersant, respectively. The relative effects of these variables have been evaluated in half-normal plots and Pareto charts using central composite rotatable design. A quadratic response model has been developed for both Fe grade and recovery and optimized within the experimental range. The optimum reagent dosages are found to be as follows： collector concentration of 243.58 g/t, dispersant concentration of 195.67 g/t, pH 8.69, and conditioning time of 4.8 min to achieve the maximum Fe grade of 64.25% with 67.33% recovery. The predictions of the model with regard to iron grade and recovery are in good agreement with the experimental results.

关键词： hematite iron ore treatment flotation metal recovery design of experiments mathematical models opti-mization

Enhanced Performance of Discharge Plasma in Raw Engine Exhaust Treatment-Operation under Different Temperatures and Loads

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Plasma Science and Technology 2005年第4期7卷 2943-2946页

作者： b S Rajanikanth A D Srinivasan Subhankar das Dept.of High Voltage Engineering Indian Institute of Science Bangalore 560012IndiaDept.of High Voltage Engineering Indian Institute of ScienceBangalore 560012IndiaDept.of High Voltage Engineering Indian Institute of ScienceBangalore 560012India

This paper reports improved performance of discharge plasma in raw engine exhaust treatment. For the purpose of investigation, both filtered and raw diesel engine exhaust were separately treated by the discharge plasma. In raw exhaust environment, the discharge plasma exhibits a superior performance with regard to NOx removal, energy consmnption and formation of by-products. In this study, experiments were conducted at conditions of different temperatures and loads.

关键词： raw diesel engine exhaust discharge plasma NOx removal

Magnetic and flotation studies of banded hematite quartzite (bHQ) ore for the production of pellet grade concentrate

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International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 675-682页

作者： b. das b.K.Mishra S. Prakash S.K.das P.S.R.Reddy S.I.Angadi Institute of Minerals and Materials Technology Council of Scientific & Industrial Research (CSIR)

To identify and establish beneficiation techniques for banded hematite quartzite （bHQ） iron ore, a comprehensive research on bHQ ore treatment was carried out. The bHQ ore was assayed as 38.9wt% Fe, 42.5wt% SiO2, and 1.0wt% Al2O3. In this ore, hematite and quartz are present as the major mineral phases where goethite, martite, and magnetite are present in small amounts. The liberation of hematite particles can be enhanced to about 82% by reducing the particle size to below 63 μm. The rejection of silica particles can be obtained by magnetic and flotation separation techniques. Overall, the bHQ ore can be enriched to 65.3wt% Fe at 61.9% iron recovery. A flowsheet has been suggested for the commercial exploitation of the bHQ ore.

关键词： hematite beneficiation magnetic separation flotation pelletizing

Variability and divergence in Pongamia pinnata for further use in tree improvement

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Journal of Forestry Research 2011年第2期22卷 193-200页

作者： b.N.Divakara Rameshwar das Institute of Forest Productivity Indian Council of Forestry Research and Education

A total of 24 candidate plus trees（CPTs） of Pongamia pinnata（L.） *** selected to elucidate their variation and diversity based on thirteen quantitative traits（4 pod traits,6 seed traits of parent trees and 3 progeny traits） at Forest Research Centre,Institute of Forest Productivity-Mandar,Ranchi district during *** results show that,CPT-19 had maximum for seven traits viz,pod length（65.6 mm）,100-pod weight（542.4 g）,seed 2D（two dimension） area（351.2 mm2）,seed length（27.9 mm）,seed breadth（17.4 mm）,100-seed weight（217.9 g） and plant height（164.3 cm）.The traits,100-pod weight and 100-seed weight had a high heritability（98.4%,96.9%） accompanied with high genetic advance（46.0%,34.9%）.There is a positive significant correlation between 100-pod weight and 100-seed weight traits at both genotypic and phenotypic levels with plant height,collar diameter and volume index at 30 MAS（months after sowing）.Volume index expressed a moderate heritability（47.4%） accompanied with high genetic advance（48.4%）,indicating that the character is governed by additive gene *** divergence study,24 accessions were grouped into 6 clusters on the basis of non-hierarchical euclidian cluster *** genotypes in cluster IV（CPT-5,CPT-6,CPT-7,CPT-12,CPT-16,CPT18,CPT-22） and cluster III（CPT-4,CPT-8,CPT-9,CPT-20,CPT-21） were most heterogeneous and can be best used within group *** wide diversity exists between the cluster V and II,followed by cluster II and I and crosses between CPTs of these clusters may result in substantial *** is revealed that the existence of substantial variation and diversity can be utilized for genetic resource conservation and further tree improvement programmers of the species.

关键词： Pongamia pinnata heritability genetic advance correlation path analysis image analyzer diversity analysis

COMPUTATION OF RETURN FLOWS DUE TO NAVIGATION TRAFFICS IN RESTRICTED WATERWAYS

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International Journal of Sediment Research 2006年第4期21卷 249-260页

作者： b. S. MAZUMDER S. K. das S. N. das Indian Statistical Institute Kolkata-700 108 IndiaProf. International Institute of Information Technology Pune India Prof. Assis. Res. Officer Central Water and Power Research Station Pune-411 024 India

The paper deals with the development of an empirical model to compute the return flow due to the movement of navigation traffics in restricted waterway when the speed of the navigation traffic is under sub-critical range. The velocity profile of the return flow is modelled, where the functional dependence with respect to ambient flow, principal dimensions of the vessel, wetted cross-sectional area of the river, width and average depth of the river, and the lateral distance of the vessel from the bank are implicitly considered. This model has been validated with the observed data collected from the four specific sites, such as Kampsville, Apple River Island, Goose Island and Clarks Ferry of Illinois River during barge-tow movement. The present model shows significant improvement of return flow prediction in comparison to earlier empirical results. This model has also the ability to determine the locus of zero velocity point.

关键词： Return flow Navigation traffic Empirical model Restricted waterway barge-tow Zero velocity point Froude number

Optimization of parameters for cerium(Ⅲ) biosorption onto biowaste materials of animal and plant origin using 5-level box-behnken design: Equilibrium, kinetic, thermodynamic and regeneration studies

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Journal of Rare Earths 2014年第8期32卷 745-758页

作者： Jaya Sre Varsihini C Devlina das Nilanjana das bioremediation Laboratory Environmental Biotechnology Division School of Biosciences and Technology VIT University

Response surface methodology （RSM） employing 5-level box-behnken design was used to optimize the biosorption of cerium（III） onto biowaste materials of animal and plant origin viz. prawn carapace （PC） and corn style （CS）. Various process parameters viz. pH （A：3.0-9.0）, biomass dosage （b：0.05-0.35 g/L）, initial metal concentration （C：50-350 mg/L）, contact time （D：2-6 h） and temperature （E：20-60 ℃ were chosen for optimization. A log transformation was suggested by the box-Cox plot in the present case. A low p-value of〈0.0001 validated the significance of the model. Maximum Ce（III） uptake of 218.3 mg/g for PC and 180.2 mg/g for CS was noted under optimum conditions. Among the equilibrium isotherms, Freundlich model was found to be the best fitted one suggesting a heterogeneous mode of biosorption on PC whereas Langmuir model showed the best fit suggesting homogeneous mode of cerium biosorption on CS. This was further confirmed by scanning electron microscopy （SEM）. Kinetic studies showed better applicability of pseudo-first order model suggesting physisorption as phenomena underlying the process. Film-diffusion was suggested by the non-linearity of the boyd plot. Thermodynamic studies showed that the process was endothermic and spontaneous. FTIR analysis confirmed a major involvement of the participation of amide, amines, ketones and primary alcohol groups during Ce（III） biosorption. EDAX analysis confirmed the major participation of carbon group during Ce（III） biosorption. This was the first report on parameter optimization of Ce（III） biosorption onto biowaste materials using 5-level box-behnken experimental design which might be helpful for the recovery of Ce（III） from aqueous environment.

关键词： box-behnken design biosorption cerium(III) corn style prawn carapace rare earth metals