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Measurement of bit-rock interface temperature and wear rate of the tungsten carbide drill bit during rotary drilling

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Friction 2020年第6期8卷 1073-1082页

作者： vijay kumar shankar Bijay Mihir KUNAR Chivukula Suryanarayana MURTHY M R RAMESH Department of Mining Engineering National Institute of Technology KarnatakaSurathkal 575025India Department of Mechanical Engineering National Institute of Technology KarnatakaSurathkal 575025India

Rock drilling is an essential operation in mining *** at the bit-rock interface plays a major role in the wear rate of the drill *** paper primarily focuses on the wear rate of tungsten carbide(WC)drill bit and the interrelationship between temperature and wear rate during rotary drilling operations conducted using a computer numerical control(CNC)*** interrelationship between the temperature and wear rate was studied with regard to three types of rock samples,i.e.,fine-grained sandstone(FG)of uniaxial compressive strength(UCS)that is 17.83 MPa,medium-grained sandstone(MG)of UCS that is 13.70 MPa,and fine-grained sandstone pink(FGP)of UCS that is 51.67 *** rate of the drill bit has been measured using controlled parameters,i.e.,drill bit diameter(6,8,10,12,and 16 mm),spindle speed(250,300,350,400,and 450 rpm),and penetration rate(2,4,6,8,and 10 mm/min),***,a fully instrumented laboratory drilling set-up was *** weight of each bit was measured after the bit reached 30 mm depth in each type of the rock ***,effects of the bit-rock interface temperature and operational parameters on wear rate of the drill bits were *** results show that the wear rate of drill bits increased with an increase in temperature for all the bit-rock combinations *** is due to the silica content of the rock sample,which leads to an increase in the frictional heat between the bit-rock ***,in case of medium-grained sandstone,the weight percentage(wt%)of SiO2 is around 7.23 wt%,which presents a very low wear rate coefficient of 6.33×10^–2 mg/(N?m).Moreover,the temperature rise during drilling is also minimum,i.e.,around 74℃,in comparison to that of fine-grained sandstone and fine-grained sandstone *** addition,this paper develops the relationship between temperature and wear rate characteristics by employing simple linear regression analysis.

关键词： temperature wear rate drilling simple linear regression

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Analysis of docosanol using GC/MS:Method development,validation,and application to ex vivo human skin permeation studies

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Journal of Pharmaceutical Analysis 2022年第2期12卷 287-292页

作者： vijay kumar shankar Mei Wang Srinivas Ajjarapu Praveen Kolimi Bharathi Avula Reena Murthy Ikhlas Khan Sathyanarayana Narasimha Murthy Department of Pharmaceutics and Drug Delivery University of MississippiOxfordMS38677USA Natural Products Utilization Research Unit Agricultural Research ServiceU.S.Department of AgricultureOxfordMS38677USA National Center for Natural Products Research Research Institute of Pharmaceutical SciencesSchool of PharmacyUniversity of MississippiOxfordMS38677USA Topical Products Testing LLC OxfordMS38677USA

Docosanol is the only US Food and Drug Administration(FDA)approved over-the-counter topical product for treating recurrent oral-facial herpes simplex *** analytical methods for docosanol are required to demonstrate the bioequivalence of docosanol topical products.A gas chromatography/selected ion monitoring mode mass spectrometry(GC/SIM-MS)method was developed and validated for docosanol determination in biological *** and isopropyl palmitate(internal standard)were separated on a high-polarity GC capillary column with(88%cyanopropy)aryl-polysiloxane employed as the stationary *** ions of m/z 83 and 256 were selected to monitor docosanol and isopropyl palmitate,respectively;the total run time was 20 *** GC/SIM-MS method was validated in accordance with US FDA guidelines,and the results met the US FDA acceptance *** docosanol calibration standards were linear in the 100-10000 ng/mL concentration range(R^(2)>0.994).The recoveries for docosanol from the receptor fluid and skin homogenates were>93.2%and>95.8%,*** validated method was successfully applied to analyze ex vivo human cadaver skin permeation *** applying Abreva®cream tube and Abreva®cream pump,the amount of docosanol that penetrated human cadaver skin at 48 h was 21.5±7.01 and 24.0±6.95 ng/mg,***,we concluded that the validated GC/SIM-MS was sensitive,specific,and suitable for quantifying docosanol as a quality control *** method can be used for routine analysis as a costeffective alternative to other techniques.

关键词： Docosanol Fatty alcohols Gas chromatography-mass spectrometry Topical formulation Skin permeation

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Dynamics of some new solutions to the coupled DSW equations traveling horizontally on the seabed

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Journal of Ocean Engineering and Science 2024年第2期9卷 154-163页

作者： Raj kumar Ravi shankar Verma Department of Mathematics Faculty of Engineering&TechnologyVeer Bahadur Singh Purvanchal UniversityJaunpur 222003India

The system of(1+1)-coupled Drinfel’d-Sokolov-Wilson equations describes the surface gravity waves travelling horizontally on the *** objective of the present research is to construct a new variety of analytical solutions for the *** invariants are derived with the aid of Killing form by using the optimal algebra classification via Lie symmetry *** invariant solutions involve time,space variables,and arbitrary *** adequate constraints on arbitrary constants,solutions are represented graphically to make them more applicable in designing sea *** behavior of solutions shows asymptotic,bell-shaped,bright and dark soliton,bright soliton,parabolic,bright and kink,kink,and periodic *** constructed results are novel as the reported results[26,28,29,30,33,38,42,49]can be deduced from the results derived in this *** remaining solutions derived in this study,are absolutely different from the earlier *** this study,the physical character of analytical solutions of the system could aid coastal engineers in creating models of beaches and ports.

关键词： Coupled Drinfel’d-Sokolov-Wilson model Invariants Killing form Optimal sub algebra Lie symmetry reductions

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Numerical modelling of post-failure behaviors of coal specimens

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 514-531页

作者： Ajeet Yadav Bhaskara Behera Gauri shankar Prasad Singh Sanjay kumar Sharma Department of Mining Engineering Indian Institute of Technology(Banaras Hindu University)VaranasiUttar Pradesh221005India

A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having different w/h *** model was developed based on back-analysis of the complete stress-strain behavior of specimens belonging to six different Indian coal seams with different w/h ratios of 0.5 *** was found that the simultaneous degradation of the cohesion and friction angle of the Mohr-Coulomb rock material characterizes the post-peak strength behavior of the *** resulting expressions are simplistic as they require parameters that can be easily determined using uniaxial and triaxial compression ***,the developed model was validated by simulating the triaxial tests of coal specimens with different sizes under varying confining stresses and comparing its findings with the published test *** study showed that its implementation in the numerical model could reproduce laboratory-observed mechanical response,deformation behavior,and failure mechanism very closely.

关键词： Strain softening Dilatancy Interface Shape effect Residual strength

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Optimization of variables and assessment of in-vitro and in-vivo antihyperlipidemic activity of Eudragit RS nanoparticles containing simvastatin

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Particuology 2024年第7期90卷 189-198页

作者： Bina Gidwani Vishal Jain Veenu Joshi Ravindra kumar Pandey Shiv shankar Shukla Amber Vyas Columbia Institute of Pharmacy Raipur(C.G.)India University Institute of Pharmacy Pt Ravishankar Shukla UniversityRaipur(C.G.)India Center for Basic Science and Research Pt Ravishankar Shukla UniversityRaipur(C.G.)India

Simvastatin, a BCS class II drug, is associated with poor aqueous solubility, first-pass metabolism and short half-life. In the present work, nanoparticles were prepared and evaluated. Optimization of formulation and process parameters was done through the use of independent and dependent variables. Preliminary studies were done to determine suitable range of the concentration of Eudragit polymer (10%–30%) and the ratio of drug to polymer (1:1 to 1:5) for the formation of nanoparticles by emulsification and a solvent evaporation technique. Results revealed that the mean size of nanoparticles was affected by stirring speed from 5000 RPM, 8000 RPM, and 12000 RPM. The results of increase in association efficiency and percent yield with increase in amount of drug from 100 mg, 150 mg, and 200 mg in selected range were observed. In-vitro release studies showed that two formulations possess highest initial burst and slow sustained drug release. There was 2.93-fold decrease in total cholesterol and 3.27-fold increases in triglyceride level during in-vivo study.

关键词： Simvastatin Eudragit RS 100 Nanoparticles Hyperlipidemia

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Fast internal preheating of 4680 lithium-ion batteries in cold environments

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Nano Research 2024年第10期17卷 8794-8802页

作者： Chuyue Guan Harrison Szeto Olivia Wander vijay kumar Raphaele JClément Yangying Zhu Department of Mechanical Engineering University of California Santa BarbaraSanta BarbaraCA 93106USA Department of Chemistry and Biochemistry University of California Santa BarbaraSanta BarbaraCA 93106USA Department of Materials University of California Santa BarbaraSanta BarbaraCA 93106USA

Lithium-ion batteries are expected to operate within a narrow temperature window around room temperature for optimal performance and ***,in cold environments,electric vehicle battery packs must be extensively preheated prior to charge or ***,conventional preheating is accomplished externally,which is slow and thus significantly increases charging ***,internal heating has been demonstrated as a potential solution to quickly and uniformly preheat a lithium-ion pouch ***,internal heating has not been evaluated in other battery formats such as cylindrical *** this work,we present a numerical model of a 4680 battery with internal heaters for fast preheating in cold *** effects that the number of heater layers,heating duration,resting duration,environmental temperature,and boundary heat transfer coefficient have on the temperature heterogeneity of the battery were *** results show that internal heating alone reduces the temperature variation within the battery by a factor of 5 compared to external heating,and by a factor of 20 when combining internal and external *** study further proves that internal preheating of lithium-ion batteries is a promising thermal management strategy,and provides guidance on potential design considerations and heating protocols to implement internal heating.

关键词： lithium-ion battery 4680 battery thermal management internal battery preheating COMSOL Multiphysics thermal simulation battery temperature heterogeneity

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Structural build-up model for three-dimensional concrete printing based on kinetics theory

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 998-1014页

作者： Prabhat Ranjan PREM P.S.AMBILY shankar kumar Greeshma GIRIDHAR Dengwu JIAO Advanced Materials Laboratory CSIR-Structural Engineering Research CentreChennai 600113India Department of Architecture and Civil Engineering City University of Hong KongHong Kong 999077China

The thixotropic structural build-up is crucial in extrusion-based three-dimensional(3D)concrete *** paper uses a theoretical model to predict the evolution of static and dynamic yield stress for printed *** model employs a structural kinetics framework to create a time-independent constitutive link between shear stress and shear *** model considers flocculation,deflocculation,and chemical hydration to anticipate structural *** reversible and irreversible contributions that occur throughout the build-up,breakdown,and hydration are defined based on the proposed structural ***,detailed parametric studies are conducted to evaluate the impact of model *** is revealed that the proposed model is in good agreement with the experimental results,and it effectively characterizes the structural build-up of 3D printable concrete.

关键词： structural build-up rheology thixotropy 3D printable concrete kinetics theory ultra high performance concrete

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Gas hydrate saturation from NGHP 02 LWD data in the Mahanadi Basin

Energy Geoscience

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Energy Geoscience 2024年第2期5卷 279-289页

作者： Uma shankar Pradeep kumar Yadav Sneha Devi Udham Singh Yadav Department of Geophysics Institute of ScienceBHUVaranasi221005India Oil and Natural Gas Corporation Ltd. Gas Hydrate Research&Technology Centre(GHRTC)Panvel410221Navi MumbaiIndia

During the Indian National Gas Hydrate Program(NGHP)Expedition 02,Logging-while-drilling(LWD)logs were acquired at three sites(NGHP-02-11,NGHP-02-12,and NGHP-02-13)across the Mahanadi Basin in area *** applied rock physics theory to available sonic velocity logs to know the distribution of gas hydrate at site NGHP-02-11 and *** physics modeling using sonic velocity at well location shows that gas hydrate is distributed mainly within the depth intervals of 150-265 m and 100 -215 mbsf at site NGHP-02-11 and NGHP-02-13,respectively,with an average saturation of about 4%of the pore space and the maximum concentration of about 40%of the pore space at 250 m depth at site NGHP-02-11,and at site NGHP-02-13 an average saturation of about 2%of the pore space and the maximum concentration of about 20%of the pore space at 246 m depth,as gas hydrate is distributed mainly within 100-246 mbsf at this *** of gas hydrate estimated from the electrical resistivity method using density derived porosity and electrical resistivity logs from Archie's empirical formula shows high saturation compared to that from the sonic ***,estimates of hydrate saturation based on sonic P-wave velocity may differ significantly from that based on resistivity,because gas and hydrate have higher resistivity than conductive pore fluid and sonic P-wave velocity shows strong effect on gas hydrate as a small amount of gas reduces the velocity significantly while increasing velocity due to the presence of *** site NGHP-02-11,gas hydrate saturation is in the range of 15%e30%,in two zones between 150-180 and 245-265 *** NGHP-02-012 shows a gas hydrate saturation of 20%e30%in the zone between 100 and 207 *** NGHP-02-13 shows a gas hydrate saturation up to 30%in the zone between 215 and 246 *** observations from rock physics modeling and Archie’s approximation show the gas hydrate concentrations are relatively low(<4%of the pore space)at the sites of the

关键词： Mahanadi Basin Gas hydrate Sonic log Effective medium modeling Electrical resistivity log Archie’s analysis Gas hydrate saturation

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Nano/Micro-Structural Supramolecular Biopolymers: Innovative Networks with the Boundless Potential in Sustainable Agriculture

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Nano-Micro Letters 2024年第8期16卷 79-101页

作者： Roohallah Saberi Riseh Mohadeseh Hassanisaadi Masoumeh Vatankhah Rajender S.Varma vijay kumar Thakur Department of Plant Protection Faculty of AgricultureVali-e-Asr University of RafsanjanImam Khomeini SquareRafsanjan ***Iran Centre of Excellence for Research in Sustainable Chemistry Department of ChemistryFederal University of São CarlosSão CarlosSP 13565‑905Brazil Biorefining and Advanced Materials Research Center Scotland’s Rural Collage(SRUC)Edinburgh EH93JGUK

Sustainable agriculture plays a crucial role in meeting the growing global demand for food while minimizing adverse environmental impacts from the overuse of synthetic pesticides and conventional *** this context,renewable biopolymers being more sustainable offer a viable solution to improve agricultural sustainability and ***/micro-structural supramolecular biopolymers are among these innovative biopolymers that are much sought after for their unique *** biomaterials have complex hierarchical structures,great stability,adjustable mechanical strength,stimuli-responsiveness,and self-healing *** molecules may be added to their flexible structure,for enabling novel agricultural *** overview scrutinizes how nano/micro-structural supramolecular biopolymers may radically alter farming practices and solve lingering problems in agricultural sector namely improve agricultural production,soil health,and resource *** bioactive ingredient released from biopolymers allows the tailored administration of agrochemicals,bioactive agents,and biostimulators as they enhance nutrient absorption,moisture retention,and root ***/micro-structural supramolecular biopolymers may protect crops by appending antimicrobials and biosensing entities while their eco-friendliness supports sustainable *** their potential,further studies are warranted to understand and optimize their usage in agricultural *** effort seeks to bridge the knowledge gap by investigating their applications,challenges,and future prospects in the agricultural *** experimental investigations and theoretical modeling,this overview aims to provide valuable insights into the practical implementation and optimization of supramolecular biopolymers in sustainable agriculture,ultimately contributing to the development of innovative and eco-friendly solutions to enhance agricultural productivity while minimizing envir

关键词： Supramolecular Biopolymers Sustainable agriculture Nanotechnology

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Autologous peripheral blood-derived orthobiologics:Different types and their effectiveness in managing knee osteoarthritis

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World Journal of Orthopedics 2024年第5期15卷 400-403页

作者： Ashim Gupta vijay kumar Jain Department of Orthopaedics and Regenerative Medicine Future BiologicsLawrencevilleGA 30043United States Department of Orthopaedics South Texas Orthopaedic Research Institute(STORI Inc.)LaredoTX 78045United States Department of Regenerative Medicine BioIntegrateLawrencevilleGA 30043United States Department of Orthopaedics and Regenerative Medicine Regenerative OrthopaedicsNoida 201301India Department of Orthopaedics Atal Bihari Vajpayee Institute of Medical SciencesDr.Ram Manohar Lohia HospitalDelhi 110001New DelhiIndia

Knees are the most commonly impacted weight-bearing joints in osteoarthritis(OA),affecting millions of people *** increasing life spans and obesity rates,the incidence of knee OA will further increase,leading to a significant increase in the economic *** treatment modalities utilized to manage knee OA have *** the last decade,the role of various autologous peripheral blood-derived orthobiologics(APBOs)for the treatment of knee OA has been extensively *** editorial provided an overview and focused on defining and shedding light on the current state of evidence based on the most recent published clinical studies concerning the use of APBO for the management of knee *** numerous studies have demonstrated promising results for these preparations,a notable gap exists in the comparative analysis of these diverse *** absence of head-to-head studies poses a considerable challenge for physicians/surgeons in determining the optimal preparation for managing knee OA and achieving sustained longterm ***,more adequately powered,multicenter,prospective,doubleblind,randomized controlled trials with longer follow-ups are needed to establish the long-term efficacy and to aid physicians/surgeons in determining the optimal APBO for the management of knee OA.

关键词： Knee osteoarthritis Platelet-rich plasma Platelet lysate Autologous conditioned serum Gold-induced cytokine Plasma rich in growth factors Growth factor concentrate Autologous protein solution Platelet-rich fibrin Hyperacute serum

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