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A Simple and Robust Mesh Refinement Implementation in Abaqus for Phase Field Modelling of Brittle Fracture
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作者 Anshul Pandey sachin kumar 《Computer Modeling in Engineering & Sciences》 2025年第9期3251-3286,共36页
The phase field model can coherently address the relatively complex fracture phenomenon,such as crack nucleation,branching,deflection,etc.The model has been extensively implemented in the finite element package Abaqus... The phase field model can coherently address the relatively complex fracture phenomenon,such as crack nucleation,branching,deflection,etc.The model has been extensively implemented in the finite element package Abaqus to solve brittle fracture problems in recent studies.However,accurate numerical analysis typically requires fine meshes to model the evolving crack path effectively.A broad region must be discretized without prior knowledge of the crack path,further augmenting the computational expenses.In this proposed work,we present an automated framework utilizing a posteriori error-indicator(MISESERI)to demarcate and sufficiently refine the mesh along the anticipated crack path.This eliminates the need for manual mesh refinement based on previous experimental/computational results or heuristic judgment.The proposed Python-based framework integrates the preanalysis,sufficient mesh refinement,and subsequent phase-field model-based numerical analysis with user-defined subroutines in a single streamlined pass.The novelty of the proposed work lies in integrating Abaqus’s native error estimation and mesh refinement capability,tailored explicitly for phase-field simulations.The proposed methodology aims to reduce the computational resource requirement,thereby enhancing the efficiency of the phase-field simulations while preserving the solution accuracy,making the framework particularly advantageous for complex fracture problems where the computational/experimental results are limited or unavailable.Several benchmark numerical problems are solved to showcase the effectiveness and accuracy of the proposed approach.The numerical examples present the proposed approach’s efficacy in the case of a complex mixed-mode fracture problem.The results show significant reductions in computational resources compared to traditional phase-field methods,which is promising. 展开更多
关键词 PHASE-FIELD brittle fracture mesh refinement Abaqus UEL Python scripting
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Trigonelline mitigates bleomycin-induced idiopathic pulmonary fibrosis in mice 被引量:1
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作者 Swapnil Gavhane Chandrakant Gawli +7 位作者 sachin kumar Biswajit Das Gayatri Marathe Vishal S.Patil Harun M.Patel Basavaraj Bommanahalli Chanakya Nath Kundu Chandragouda R.Patil 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2024年第9期391-400,I0008-I0291,共294页
Objective:To evaluate the effect of trigonelline on bleomycin-induced idiopathic pulmonary fibrosis(IPF)and to explore its underlying mechanisms using network pharmacology.Methods:IPF was induced in C57BL/6 mice by a ... Objective:To evaluate the effect of trigonelline on bleomycin-induced idiopathic pulmonary fibrosis(IPF)and to explore its underlying mechanisms using network pharmacology.Methods:IPF was induced in C57BL/6 mice by a single intratracheal instillation of bleomycin(5 mg/kg).Trigonelline was administered at doses of 25,50,and 100 mg/kg/day orally from the 2nd day post-bleomycin induction up to the 14th day.In IPF-induced mice,lung coefficient,immune cell infiltration in bronchoalveolar lavage fluid,and oxidative stress were measured.Histological alterations in lung tissues were also assessed.Moreover,network pharmacology approach was conducted to reveal molecular interactions of bleomycin and trigonelline with targets of IPF.Results:Trigonelline treatment reduced bleomycin-induced oxidative stress and immune cell infiltration,and mitigated physiological changes in the lung tissues of mice.Moreover,trigonelline alleviated bleomycin-induced histological alterations in lung tissues.Network pharmacology analysis showed that bleomycin and trigonelline interacted with IPF targets,such as NFKB1,HDAC2,HIF1A,and TLR4.Conclusions:The interaction of trigonelline with key IPF targets and its ameliorative effects on lung damage and oxidative stress highlight its potential in treating IPF.It may be considered an antifibrotic agent for further clinical development. 展开更多
关键词 TRIGONELLINE Idiopathic pulmonary fibrosis ANTIFIBROTIC BLEOMYCIN Network pharmacology
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Non-static plane symmetric perfect fluid solutions and Killing symmetries in f(R,T)gravity
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作者 Preeti Dalal Karanjeet Singh sachin kumar 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第2期145-150,共6页
In this paper,the non-static solutions for perfect fluid distribution with plane symmetry in f(R,T)gravitational theory are obtained.Firstly,using the Lie symmetries,symmetry reductions are performed for considered ve... In this paper,the non-static solutions for perfect fluid distribution with plane symmetry in f(R,T)gravitational theory are obtained.Firstly,using the Lie symmetries,symmetry reductions are performed for considered vector fields to reduce the number of independent variables.Then,corresponding to each reduction,exact solutions are obtained.Killing vectors lead to different conserved quantities.Therefore,we figure out the Killing vector fields corresponding to all derived solutions.The derived solutions are further studied and it is observed that all of the obtained spacetimes,at least admit to the minimal symmetry group which consists of δ_(y),δ_(z) and -zδ_(y)+yδ_(z).The obtained metrics,admit to 3,4,6,and 10,Killing vector fields.Conservation of linear momentum in the direction of y and z,and angular momentum along the x axis is provided by all derived solutions. 展开更多
关键词 Einstein field equations perfect fluid solutions f(R T)gravity killing symmetries
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Evaluation of capabilities of ultrasonic energy on failure load and corrosion resistance of friction stir lap welded Al-steel joints
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作者 Tao Liu Song Gao +5 位作者 Lei Shi sachin kumar Zhi-ping Sun Wei Zhao Hui Zhang Ning Guo 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2024年第10期2489-2504,共16页
The lap joints of 6061-T6 aluminum alloy/Q235 steel were prepared by conventional friction stir welding and ultrasonic vibration enhanced friction stir welding.Firstly,the effect of ultrasonic vibration on the microst... The lap joints of 6061-T6 aluminum alloy/Q235 steel were prepared by conventional friction stir welding and ultrasonic vibration enhanced friction stir welding.Firstly,the effect of ultrasonic vibration on the microstructure and properties of joints was analyzed,and then the optimization mechanism of ultrasonic vibration on failure load and corrosion resistance of joints was elucidated.The results indicated that ultrasonic vibration could significantly improve the quality of weld formation,expand the width of interface zone,change the shape of the“hook”structure,form a macro mechanical interlock at the joint interface,and effectively refine the grain structure on the steel side.In terms of the microstructure of the joints,additional ultrasonic energy can change the microstructure characteristics at the interface,and can improve the distribution characteristics of precipitates in the weld nugget zone,significantly reducing the number of intermetallic compounds generated across the interface of the retreating side and forming micro mechanical interlock on the advancing side of the interface.After ultrasonic treatment,the failure load of the aluminum/steel lap joint increased by 20.4%,and the corrosion resistance improved by 1.304 times. 展开更多
关键词 Friction stir welding Ultrasonic vibration Aluminum/steel heterogeneous component Failure load Corrosion resistance
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Antitubercular therapy in patients with cirrhosis:Challenges and options 被引量:3
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作者 Naveen kumar Chandan kumar Kedarishetty +2 位作者 sachin kumar Vikas Khillan Shiv kumar Sarin 《World Journal of Gastroenterology》 SCIE CAS 2014年第19期5760-5772,共13页
Tuberculosis(TB)has been a human disease for centuries.Its frequency is increased manyfold in patients with liver cirrhosis.The gold standard of TB management is a 6-mo course of isoniazid,rifampicin,pyrazinamide and ... Tuberculosis(TB)has been a human disease for centuries.Its frequency is increased manyfold in patients with liver cirrhosis.The gold standard of TB management is a 6-mo course of isoniazid,rifampicin,pyrazinamide and ethambutol.Although good results are seen with this treatment in general,the management of patients with underlying cirrhosis is a challenge.The underlying depressed immune response results in alterations in many diagnostic tests.The tests used for latent TB have many flaws in this group of patients.Three of four first-line antitubercular drugs are hepatotoxic and baseline liver function is often disrupted in patients with underlying cirrhosis.Frequency of hepatotoxicity is increased in patients with liver cirrhosis,frequently leading to severe liver failure.There are no established guidelines for the treatment of TB in relation to the severity of liver disease.There is no consensus on the frequency of liver function tests required or the cutoff used to define hepatotoxicity.No specific treatment exists for prevention or treatment of hepatotoxicity,making monitoring even more important.A high risk of multidrug-resistant TB is another major worry due to prolonged and interrupted treatment. 展开更多
关键词 Antitubercular therapy Drug hepatotoxicity Multidrug-resistant tuberculosis Immune dysfunction
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Abundant different types of exact soliton solution to the (4+1)-dimensional Fokas and (2+1)-dimensional breaking soliton equations 被引量:2
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作者 sachin kumar Monika Niwas +1 位作者 M S Osman M A Abdou 《Communications in Theoretical Physics》 SCIE CAS CSCD 2021年第10期64-80,共17页
The prime objective of this paper is to explore the new exact soliton solutions to the higher-dimensional nonlinear Fokas equation and(2+1)-dimensional breaking soliton equations via a generalized exponential rational... The prime objective of this paper is to explore the new exact soliton solutions to the higher-dimensional nonlinear Fokas equation and(2+1)-dimensional breaking soliton equations via a generalized exponential rational function(GERF) method. Many different kinds of exact soliton solution are obtained, all of which are completely novel and have never been reported in the literature before. The dynamical behaviors of some obtained exact soliton solutions are also demonstrated by a choice of appropriate values of the free constants that aid in understanding the nonlinear complex phenomena of such equations. These exact soliton solutions are observed in the shapes of different dynamical structures of localized solitary wave solutions, singular-form solitons, single solitons,double solitons, triple solitons, bell-shaped solitons, combo singular solitons, breather-type solitons,elastic interactions between triple solitons and kink waves, and elastic interactions between diverse solitons and kink waves. Because of the reduction in symbolic computation work and the additional constructed closed-form solutions, it is observed that the suggested technique is effective, robust, and straightforward. Moreover, several other types of higher-dimensional nonlinear evolution equation can be solved using the powerful GERF technique. 展开更多
关键词 nonlinear evolution equations soliton solutions exact solutions generalized exponential rational function method solitary waves
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Rate-dependent mechanical behavior of jointed rock with an impersistent joint under different infill conditions 被引量:2
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作者 sachin kumar Gaurav Tiwari +1 位作者 Venkitanarayanan Parameswaran Arghya Das 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第5期1380-1393,共14页
Transition in the rate-dependent mechanical response of rock was investigated due to the presence of impersistent joint with different infill conditions.Four types of samples,i.e.intact,jointed with no grouting,jointe... Transition in the rate-dependent mechanical response of rock was investigated due to the presence of impersistent joint with different infill conditions.Four types of samples,i.e.intact,jointed with no grouting,jointed and grouted with cement,and jointed and grouted with epoxy,were fabricated using model material.A series of dynamic split Hopkinson pressure bar(SHPB) tests was conducted on prepared samples with strain rates varying between 53-130 salong with static uniaxial compression tests(10s).Progression of fracture/failure along samples was monitored using high-speed imaging and digital image correlation(DIC).Strength was observed to be significantly lower for jointed samples as compared to intact samples.However,the increasing trend of strength with strain rates remained similar for all types of samples.Epoxy was observed to be a better grout due to greater improvement in the strength of epoxy grouted jointed samples than cement grouted samples under both static and dynamic conditions.Significant changes were observed in fracture behavior(initiation,pattern and mechanism)with strain rate for intact and jointed unfilled/grouted samples.Fracturing was dominated by shear and tensile cracks at high strain rates compared to tensile cracks at low strain rates in all samples.Unlike static loading conditions,the location of cracks initiation shifts away from joint tips with increasing strain rate and depending upon existing infill conditions(unfilled/grouted). 展开更多
关键词 Jointed rocks Grouted joint Dynamic loading Strain rates
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Review:Mg and Its Alloy--Scope, Future Perspectives and Recent Advancements in Welding and Processing 被引量:1
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作者 sachin kumar Chuansong WU 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2017年第6期1-37,共37页
This review article aims to analyze and evaluate the advantages, shortcomings, technological advancements and hereafter prospects in welding and processing of magnesium and its alloys. Studies have accounted that repl... This review article aims to analyze and evaluate the advantages, shortcomings, technological advancements and hereafter prospects in welding and processing of magnesium and its alloys. Studies have accounted that replacing other metals with Mg alloys will bring about in monumental weight reduction with significant addition in strength that could lead to dramatic transformation of metallic era of 21st century and onwards. However,wide application of Mg and its alloys depends on the development of advanced welding &joining technologies. The current paradigm and progress in welding,joining and processing of magnesium and its alloys are reviewed,and research trend in this field is briefly discussed. 展开更多
关键词 MAGNESIUM Mg ALLOY PROCESSING WELDING joining RECENT advancements
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A data mining approach to characterize road accident locations 被引量:1
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作者 sachin kumar Durga Toshniwal 《Journal of Modern Transportation》 2016年第1期62-72,共11页
Data mining has been proven as a reliable technique to analyze road accidents and provide productive results. Most of the road accident data analysis use data mining techniques, focusing on identifying factors that af... Data mining has been proven as a reliable technique to analyze road accidents and provide productive results. Most of the road accident data analysis use data mining techniques, focusing on identifying factors that affect the severity of an accident. However, any damage resulting from road accidents is always unacceptable in terms of health, property damage and other economic factors. Sometimes, it is found that road accident occurrences are more frequent at certain specific locations. The analysis of these locations can help in identifying certain road accident features that make a road accident to occur frequently in these locations. Association rule mining is one of the popular data mining techniques that identify the correlation in various attributes of road accident. In this paper, we first applied k-means algorithm to group the accident locations into three categories, high-frequency, moderate-frequency and low-frequency accident locations. k-means algorithm takes accident frequency count as a parameter to cluster the locations. Then we used association rule mining to characterize these locations. The rules revealed different factors associated with road accidents at different locations with varying accident frequencies. Theassociation rules for high-frequency accident location disclosed that intersections on highways are more dangerous for every type of accidents. High-frequency accident locations mostly involved two-wheeler accidents at hilly regions. In moderate-frequency accident locations, colonies near local roads and intersection on highway roads are found dangerous for pedestrian hit accidents. Low-frequency accident locations are scattered throughout the district and the most of the accidents at these locations were not critical. Although the data set was limited to some selected attributes, our approach extracted some useful hidden information from the data which can be utilized to take some preventive efforts in these locations. 展开更多
关键词 Road accidents Accident analysis Datamining k-Means Association rule mining
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Hyperparameter Tuning Bidirectional Gated Recurrent Unit Model for Oral Cancer Classification
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作者 K.Shankar E.Laxmi Lydia +4 位作者 sachin kumar Ali S.Abosinne Ahmed alkhayyat A.H.Abbas Sarmad Nozad Mahmood 《Computers, Materials & Continua》 SCIE EI 2022年第12期4541-4557,共17页
Oral Squamous Cell Carcinoma(OSCC)is a type of Head and Neck Squamous Cell Carcinoma(HNSCC)and it should be diagnosed at early stages to accomplish efficient treatment,increase the survival rate,and reduce death rate.... Oral Squamous Cell Carcinoma(OSCC)is a type of Head and Neck Squamous Cell Carcinoma(HNSCC)and it should be diagnosed at early stages to accomplish efficient treatment,increase the survival rate,and reduce death rate.Histopathological imaging is a wide-spread standard used for OSCC detection.However,it is a cumbersome process and demands expert’s knowledge.So,there is a need exists for automated detection ofOSCC using Artificial Intelligence(AI)and Computer Vision(CV)technologies.In this background,the current research article introduces Improved Slime Mould Algorithm with Artificial Intelligence Driven Oral Cancer Classification(ISMA-AIOCC)model on Histopathological images(HIs).The presented ISMA-AIOCC model is aimed at identification and categorization of oral cancer using HIs.At the initial stage,linear smoothing filter is applied to eradicate the noise from images.Besides,MobileNet model is employed to generate a useful set of feature vectors.Then,Bidirectional Gated Recurrent Unit(BGRU)model is exploited for classification process.At the end,ISMA algorithm is utilized to fine tune the parameters involved in BGRU model.Moreover,ISMA algorithm is created by integrating traditional SMA and ChaoticOppositional Based Learning(COBL).The proposed ISMA-AIOCC model was validated for performance using benchmark dataset and the results pointed out the supremacy of ISMA-AIOCC model over other recent approaches. 展开更多
关键词 Computer aided diagnosis deep learning BGRU biomedical imaging oral cancer histopathological images
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A Parallel Approach to Discords Discovery in Massive Time Series Data
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作者 Mikhail Zymbler Alexander Grents +1 位作者 Yana Kraeva sachin kumar 《Computers, Materials & Continua》 SCIE EI 2021年第2期1867-1878,共12页
A discord is a refinement of the concept of an anomalous subsequence of a time series.Being one of the topical issues of time series mining,discords discovery is applied in a wide range of real-world areas(medicine,as... A discord is a refinement of the concept of an anomalous subsequence of a time series.Being one of the topical issues of time series mining,discords discovery is applied in a wide range of real-world areas(medicine,astronomy,economics,climate modeling,predictive maintenance,energy consumption,etc.).In this article,we propose a novel parallel algorithm for discords discovery on high-performance cluster with nodes based on many-core accelerators in the case when time series cannot fit in the main memory.We assumed that the time series is partitioned across the cluster nodes and achieved parallelization among the cluster nodes as well as within a single node.Within a cluster node,the algorithm employs a set of matrix data structures to store and index the subsequences of a time series,and to provide an efficient vectorization of computations on the accelerator.At each node,the algorithm processes its own partition and performs in two phases,namely candidate selection and discord refinement,with each phase requiring one linear scan through the partition.Then the local discords found are combined into the global candidate set and transmitted to each cluster node.Next,a node performs refinement of the global candidate set over its own partition resulting in the local true discord set.Finally,the global true discords set is constructed as intersection of the local true discord sets.The experimental evaluation on the real computer cluster with real and synthetic time series shows a high scalability of the proposed algorithm. 展开更多
关键词 Time series discords discovery computer cluster many-core accelerator VECTORIZATION
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Errata and Addendum:Magnetic properties of an antiferromagnetic spin-1/2 XYZ model in the presence of different magnetic fields:finite-size effects of inhomogeneity property(2019,Commun.Theor.Phys.711253–1260)
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作者 sachin kumar S M Yusuf 《Communications in Theoretical Physics》 SCIE CAS CSCD 2022年第8期159-160,共2页
We report the correct results for the antiferromagnetic s=1/2 XYZ model system considered in(2019,Commun.Theor.Phys.711253).We also point out the correct model system used for the reported results therein.
关键词 spin chain magnetization susceptibility
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Deciphering the structural,morphological,and electrical properties of rare-earth incorporated barium stannate titanate dielectric material
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作者 sachin kumar Anurag Pritam +2 位作者 Vaibhav Shrivastava O.P.Thakur Vandna Luthra 《Journal of Advanced Dielectrics》 2025年第3期127-138,共12页
The primary aim of the current research is to explore the impact of yttrium-doping in barium stannate titanate(Ba_(1-1.5x)Y_(x)Ti_(1-z)Sn_(z)O_(3))to investigate the variation in its structural and electrical properti... The primary aim of the current research is to explore the impact of yttrium-doping in barium stannate titanate(Ba_(1-1.5x)Y_(x)Ti_(1-z)Sn_(z)O_(3))to investigate the variation in its structural and electrical properties.The specimens were synthesized using a solid-state method,wherein the precursors were heated together until they reacted to form the desired compounds.Subsequently,Xray diffractometric analysis was employed to confirm the crystallographic phases.Archimedes'method was used to determine the density of the material.An Electron Paramagnetic Resonance(EPR)study was conducted to examine the nature of defect centers and impurity ions within the synthesized ceramics.Furthermore,the impact of yttrium(Y)substitution on the system's morphology and grain growth was evaluated through SEM micrographs.Selective compositions were found with enhanced dielectric properties of barium titanate ceramic,exhibiting a dielectric constant of 9816 at the transition point.The highest value among all studied samples had a clear indication of DC conductivity.Piezoelectric coefficient(d_(33))and P-E hysteresis loops were also investigated for these samples,indicating potential applications in electronic devices for the modified material's improved ferroelectric properties. 展开更多
关键词 Barium titanate rare earth YTTRIUM tin EPR dielectric.
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Pyrolysis behaviour and kinetic analysis of waste polylactic acid composite reinforced with reed straw processing residue
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作者 Bo Chen Sen Ma +7 位作者 sachin kumar Zhitong Yao Wanqi Feng Jianbo Zhao Xu Zhang Di Cai Hui Cao Ian Watson 《Carbon Resources Conversion》 EI 2024年第3期74-83,共10页
The lignocellulose reinforced composites are commonly used sustainable materials with good mechanical and physical properties.Aiming to properly dispose and recover the potential value of discarded lignocellulose rein... The lignocellulose reinforced composites are commonly used sustainable materials with good mechanical and physical properties.Aiming to properly dispose and recover the potential value of discarded lignocellulose reinforced composites,the pyrolysis behaviour and kinetics of reed straw processing residual/polylactic acid(RSPR/PLA)composites,a typical 3D printing material,was investigated.Based on the TG-FTIR results,the synergistic effects between RSPR and PLA during the pyrolysis process were clarified.Compared with the FTIR spectra of PLA,the absorption peaks of CO and CO_(2)disappear in the FTIR spectra of RSPR/PLA composite,which indicates RSPR provides additional free radicals for the free radical reaction of PLA,and further promoting the decomposition.The apparent activation energy of the RSPR/PLA composite pyrolysis was calculated by two iso-conversional methods including Flynn-Wall-Ozawa(FWO)and Kissinger-Akahira-Sunose(KAS).The average Ea of the RSPR/PLA composite(122.6 kJ mol^(-1)(FWO)and 117.9 kJ mol^(-1)(KAS))was lower than that of solo pyrolysis of RSPR(138.5 kJ mol^(-1)(FWO)and 135.4 kJ mol^(-1)(KAS))and the pure PLA(197.0 kJ mol^(-1)(FWO)and 196.6 kJ mol^(-1)(KAS)).The master plot method results suggested the pyrolysis of RSPR/PLA composite followed the one-dimensional(D1)diffusion model.This work provides an environmentally friendly strategy to effective thermo-chemical upgrading of the value of discarded lignocellulose reinforced composite material. 展开更多
关键词 Biobased composite Pyrolysis conversion SYNERGY BIO-OIL Reaction kinetics
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A numerical study of the nonlinear fractional mathematical model of tumor cells in presence of chemotherapeutic treatment 被引量:2
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作者 sachin kumar Abdon Atangana 《International Journal of Biomathematics》 SCIE 2020年第3期165-181,共17页
Cancer belongs to the class of discascs which is symbolized by out of control cells growth.These cells affect DNAs and damage them.There exist many treatments avail-able in medical science as radiation therapy,targete... Cancer belongs to the class of discascs which is symbolized by out of control cells growth.These cells affect DNAs and damage them.There exist many treatments avail-able in medical science as radiation therapy,targeted therapy,surgery,palliative care and chemotherapy.Cherotherapy is one of the most popular treatments which depends on the type,location and grade of cancer.In this paper,we are working on modeling and prediction of the effect of chemotherapy on cancer cells using a fractional differen-tial equation by using the differential operator in Caputos sense.The presented model depicts the interaction between tumor,norrnal and immune cells in a tumor by using a system of four coupled fractional partial differential equations(PDEs).For this system,initial conditions of tumor cells and dimensions are taken in such a way that tumor is spread out enough in size and can be detected easily with the clinical machines.An operational matrix method with Genocchi polynomials is applied to study this system of fractional PDFs(FPDEs).An operational matrix for fract.ional differentiation is derived.Applying the collocation method and using this matrix,the nonlinear system is reduced to a system of algebraic equations,which can be solved using Newton iteration method.The salient features of this paper are the pictorial presentations of the numerical solution of the concerned equation for different particular cases to show the effect of fractional exponent on diffusive nature of immune cells,tumor cells,normal cells and chemother-apeutic drug and depict the interaction among immune cells,normal cells and tumor cells in a tumor site. 展开更多
关键词 Fractional PDE diffusion equation operational matrix Genocchi polynomial collocation method
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A malaria model with Caputo-Fabrizio and Atangana-Baleanu derivatives 被引量:2
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作者 Hamadjam Abboubakar Pushpendra kumar +1 位作者 Norodin A.Rangaig sachin kumar 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2021年第2期138-164,共27页
In this paper,we study two fractional models in the Caputo–Fabrizio sense and Atangana–Baleanu sense,in which the effects of malaria infection on mosquito biting behavior and attractiveness of humans are considered.... In this paper,we study two fractional models in the Caputo–Fabrizio sense and Atangana–Baleanu sense,in which the effects of malaria infection on mosquito biting behavior and attractiveness of humans are considered.Using Lyapunov theory,we prove the global asymptotic stability of the unique endemic equilibrium of the integer-order model,and the fractional models,whenever the basic reproduction number R0 is greater than one.By using fixed point theory,we prove existence,and conditions of the uniqueness of solutions,as well as the stability and convergence of numerical schemes.Numerical simulations for both models,using fractional Euler method and Adams–Bashforth method,respectively,are provided to confirm the effectiveness of used approximation methods for different values of the fractional-orderγ. 展开更多
关键词 Malaria fractional models Caputo-Fabrizio derivative Atangana-Baleanu derivative in the Caputo sense asymptotic stability fractional Euler method Adams-Bashforth method
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Ultrasound‑assisted osmotic dehydration,followed by convective drying of papaya:effect on physicochemical and functional quality parameters 被引量:1
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作者 Abhishek Chandra Sourabh kumar +1 位作者 sachin kumar Prabhat kumar Nema 《Systems Microbiology and Biomanufacturing》 EI 2023年第4期615-626,共12页
Papaya is a rich source of nutrients,antioxidants,and vitamins;however,it is highly perishable and hence needs to be preserved using suitable unit operations.Drying is an economical method of papaya treatment,but resu... Papaya is a rich source of nutrients,antioxidants,and vitamins;however,it is highly perishable and hence needs to be preserved using suitable unit operations.Drying is an economical method of papaya treatment,but results in the loss of essential nutrients and also degrades its pigments,color,and texture.Therefore,this work aims to utilize ultrasound and osmotic dehydration as pretreatment strategies to preserve the rich composition of papaya during conventional hot air dry-ing.The dried papaya slices were evaluated for moisture content,water activity,total phenolic content,β-carotene,color,antioxidant activity,microstructure,and texture.Results showed that sample pretreatment with 33 kHz ultrasound frequency and dehydrated with 35°Brix osmotic solution resulted in lower moisture content(<12%w.b.)and water activity(<0.41),high phenolic content(88.5 mg GAE/mL),highβ-carotene content(184.54 mg/g)and antioxidant capacity(48.3%),and preserved color after drying.The texture(hardness)of the pretreated samples was also more desirable from an industrial standpoint,which was further validated using SEM micrographs that showed a more porous structure.The study concludes that pretreatment of papaya slices with ultrasound and osmotic dehydration is recommended before drying. 展开更多
关键词 Carica papaya Microstructure Carotenoids TEXTURE DRYING PRETREATMENT
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Enhanced magneto-dielectric response in La-doped Co_(2)U hexaferrite 被引量:1
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作者 Parambir Singh Malhi Anupinder Singh +4 位作者 Mandeep Singh sachin kumar Shubhpreet Kaur Mehak Arora Ashwani kumar Sood 《Journal of Advanced Dielectrics》 CAS 2021年第6期38-51,共14页
The U-type hexaferrites(Ba_(1−3x)La_(2x))4Co_(2)Fe_(36)O_(60)(x=0,0.05,0.10,0.15,0.20,0.25)have been synthesized by auto-combustion method.The work involves the study of structural,microstructural,dielectric,magnetic ... The U-type hexaferrites(Ba_(1−3x)La_(2x))4Co_(2)Fe_(36)O_(60)(x=0,0.05,0.10,0.15,0.20,0.25)have been synthesized by auto-combustion method.The work involves the study of structural,microstructural,dielectric,magnetic and magneto-dielectric properties of the prepared materials.The structural analysis has been done by X-ray diffraction technique along with Le Bail refinement which confirmed the pure hexagonal phase for all the samples.The microstructural analysis has been carried out by field-emission scanning electron microscopy.The vibrating sample magnetometer is used to measure the magnetic properties.The sample with a composition of x=0.15 has shown the maximum magnetization of approximately 73.31 emu/g with the remnant magnetization of 38.89 emu/g and coercive field of 1.77 kOe at room temperature.Moreover,the same sample has delivered the maximum mag-netodielectric response of about 54.18%at 1.5-T field. 展开更多
关键词 U-type hexaferrites magneto-dielectric properties
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Chaos detection in SIR model with modified Beddington–De Angelis type incidence rate and saturated treatment
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作者 Shikha Jain sachin kumar 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2021年第6期56-74,共19页
In this paper, we construct an SIR epidemic model with a modified Beddington–DeAngelis type incidence rate and saturated treatment rate. We modify the incidence rateto incorporate the isolation of infected individual... In this paper, we construct an SIR epidemic model with a modified Beddington–DeAngelis type incidence rate and saturated treatment rate. We modify the incidence rateto incorporate the isolation of infected individuals after detection, and separation of somesusceptible individuals from the rest to avoid the infection, without an increase in thenumber of classes. We find that the system has a unique disease-free equilibrium (DFE)which is locally asymptotically stable when the reproduction number is less than unity.The multiple endemic equilibria may exist irrespective of the basic reproduction number.The existence of bistability is encountered. Supercritical transcritical (forward), as wellas subcritical transcritical (backward) bifurcation, may occur at R0 = 1 where contactrate, β = β∗ acts as the bifurcation parameter. Therefore, DFE need not be globallystable. The conditions for the existence of Andronov–Hopf bifurcation are deduced withmaximum treatment capacity, c = c0 as the bifurcation parameter. The impacts of isolation of confirmed infected cases and separation of some susceptible from rest are studiednumerically as well as the effect of saturation in treatment. The existence of chaoticbehavior is deduced by showing the maximum Lyapunov exponent to be positive as wellas the sensitivity to initial conditions. The computation of the Kalpan–Yorke dimensionto be fractional confirms the existence of fractal-type strange attractor. The positiveKolmogorov–Sinai entropy further strengthens the claim of the existence of chaos. 展开更多
关键词 Beddington–De Angelis type incidence rate saturated treatment stability BIFURCATION Lyapunov exponent CHAOS
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Specific wave profiles and closed-form soliton solutions for generalized nonlinear wave equation in(3+1)-dimensions with gas bubbles in hydrodynamics and fluids
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作者 sachin kumar Ihsanullah Hamid M.A.Abdou 《Journal of Ocean Engineering and Science》 SCIE 2023年第1期91-102,共12页
Nonlinear evolution equations(NLEEs)are frequently employed to determine the fundamental principles of natural phenomena.Nonlinear equations are studied extensively in nonlinear sciences,ocean physics,fluid dynamics,p... Nonlinear evolution equations(NLEEs)are frequently employed to determine the fundamental principles of natural phenomena.Nonlinear equations are studied extensively in nonlinear sciences,ocean physics,fluid dynamics,plasma physics,scientific applications,and marine engineering.The generalized exponen-tial rational function(GERF)technique is used in this article to seek several closed-form wave solutions and the evolving dynamics of different wave profiles to the generalized nonlinear wave equation in(3+1)dimensions,which explains several more nonlinear phenomena in liquids,including gas bubbles.A large number of closed-form wave solutions are generated,including trigonometric function solutions,hyper-bolic trigonometric function solutions,and exponential rational functional solutions.In the dynamics of distinct solitary waves,a variety of soliton solutions are obtained,including single soliton,multi-wave structure soliton,kink-type soliton,combo singular soliton,and singularity-form wave profiles.These de-termined solutions have never previously been published.The dynamical wave structures of some analyt-ical solutions are graphically demonstrated using three-dimensional graphics by providing suitable values to free parameters.This technique can also be used to obtain the soliton solutions of other well-known equations in engineering physics,fluid dynamics,and other fields of nonlinear sciences. 展开更多
关键词 Closed-form solutions Dynamical wave patterns Analytic solutions Nonlinear wave equation GERF Method Solitary waves SOLITONS
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