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A Numerical Analysis of Turbulent Compressible Radial Channel Flow with Particular Reference to Pneumatic Controllers

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Journal of Thermal Science 2004年第1期13卷 24-29页

作者： Gilles roy Dinh Vo-Ngoc Vadim Bravine Faculty of Engineering Université de MonctonMonctonNBCanadaE1A 3E9Faculty of EngineeringUniversité de MonctonMonctonNBCanadaE1A 3E9Faculty of EngineeringUniversité de MonctonMonctonNBCanadaE1A 3E9

A numerical analysis of turbulent axisymmetric radial compressible channel flow between a nozzle and a flat plate is presented in this paper. In particular, the application of this type of flow situation in pneumatic dimensional control systems is considered. The Spalart-Allmaras one-equation turbulence model is used. The resulting highly coupled PDE system has been solved using the control volume based numerical approach where the power-law scheme was used extensively to compute the diffusive and convective fluxes of momentum. Results show that local Mach numbers can easily achieve and surpass unity for typical industrial configurations. Also, in the case of a standard industrial nozzle geometry, the presence of a toroidal recirculation zone that moves radially outward is clearly identified in most cases. Separated flow areas are of particular concern as it has been shown previously that they can cause nozzle fouling in industrial applications. It has been shown that the size of this region is dependant on feed pressure. Considerable differences between results obtained using the Spalart-Allmaras and standard k- εturbulence models have also been noticed.

关键词： compressible radial flow numerical simulation pneumatic controllers impinging jet with confinement.

A review of age-old antimalarial drug to combat malaria:efficacy upgradation by nanotechnology based drug delivery

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Asian Pacific Journal of Tropical Medicine 2014年第9期7卷 673-679页

作者： Satyajit Tripathy Somenath roy Immunology and Microbiology Laboratory Department of Human Physiology with Community HealthVidyasagar UniversityMidnapore-721102West BengalIndia

Malaria is uncontrolled burden in the world till *** of different efforts to develop antimalarial drug for decades,any anti-malarial drug can able to eradicate completely till *** anti-malarial substances are practically ineffectual because of their physicochemical limitations,cytotoxicity,chemical instability and degradation,and limited activities against intracellular *** into consideration,the amount of research is going to conduct in the field of nanoparticle based drug delivery systems,lead to new ways of improving the treatment of infectious *** study has focused on the progress and advancement of research on nanotechnology based drug delivery to eradicate the *** like to focus the efficacy of nanotechnology based drug application for the opening out of novel chemotherapeutics in laboratory research,which may show the way to better use with age-old antimalarial drug and may draw the attention of pharmaceutical industries for the improvement and designing of effective anti-malarial drugs in future.

关键词： Nanotechnology Age-old drug Drug efficacy Antimalaria Nanomedicine

A new four-dimensional chaotic system with first Lyapunov exponent of about 22,hyperbolic curve and circular paraboloid types of equilibria and its switching synchronization by an adaptive global integral sliding mode control

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Chinese Physics B 2018年第4期27卷 214-227页

作者： Jay Prakash Singh Binoy Krishna roy Zhouchao Wei Department of Electrical Engineering National Institute of Technology Silchar Silchar 788010 India School of Mathematics and Physics China University of Geosciences Wuhan 430074 China

This paper presents a new four-dimensional（4 D） autonomous chaotic system which has first Lyapunov exponent of about 22 and is comparatively larger than many existing three-dimensional（3 D） and 4 D chaotic *** proposed system exhibits hyperbolic curve and circular paraboloid types of *** system has all zero eigenvalues for a particular case of an equilibrium *** system has various dynamical behaviors like hyperchaotic,chaotic,periodic,and *** system also exhibits coexistence of *** behavior of the new system is validated using circuit *** an interesting switching synchronization phenomenon is proposed for the new chaotic *** adaptive global integral sliding mode control is designed for the switching synchronization of the proposed *** the switching synchronization,the synchronization is shown for the switching chaotic,stable,periodic,and hybrid synchronization *** of the controller designed in the paper is compared with an existing controller.

关键词： new hyperchaotic system maximum chaos an infinite number of equilibria hidden attractors switching synchronization global sliding mode control

Role of prebiotics, probiotics, and synbiotics in management of inflammatory bowel disease: Current perspectives

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World Journal of Gastroenterology 2023年第14期29卷 2078-2100页

作者： Supriya roy Suneela Dhaneshwar Amity Institute of Pharmacy LucknowAmity University Uttar PradeshSector 125Noida 201313Uttar PradeshIndia Amity Institute of Pharmacy Amity University MaharashtraMumbai 410206MaharashtraIndia

Experimental evidence supports the fact that changes in the bowel microflora due to environmental or dietary factors have been investigated as implicating factors in the etiopathogenesis of inflammatory bowel disease(IBD).The amassing knowledge that the inhabited microbiome regulates the gut physiology and immune functions in IBD,has led researchers to explore the effectiveness of prebiotics,probiotics,and synbiotics in treating *** therapeutic approach focuses on restoring the dynamic balance between the microflora and host defense mechanisms in the intestinal mucosa to prevent the onset and persistence of intestinal *** microbial strains and carbohydrate blends,along with their combinations have been examined in experimental colitis models and clinical trials,and the results indicated that it can be an attractive therapeutic strategy for the suppression of inflammation,remission induction,and relapse prevention in IBD with minimal side *** mechanisms of action of probiotics(for e.g.,Lactobacillus species,and Bifidobacterium species)have been reported such as suppression of pathogen growth by releasing certain antimicrobial mediators(lactic and hydrogen peroxide,acetic acid,and bacteriocins),immunomodulation and initiation of an immune response,enhancement of barrier activity,and suppression of human T-cell *** such as lactulose,lactosucrose,oligofructose,and inulin have been found to induce the growth of certain types of host microflora,resulting in an enriched enteric *** non-digestible food dietary components have been reported to exert anti-inflammatory effects by inhibiting the expression of tumor necrosis factor-α-related cytokines while augmenting interleukin-10 *** proand prebiotics has established their efficacy in healthy subjects,a better understanding of the luminal ecosystem is required to determine which specific bacterial strain or combination of probiotics and prebiotics

关键词： Ulcerative colitis Crohn’s disease Pouchitis Dysbiosis Microbiota Inflammation

Challenges in managing hepatitis C virus infection in cancer patients

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World Journal of Gastroenterology 2014年第11期20卷 2771-2776页

作者： roy A Borchardt Harrys A Torres Department of Infectious Diseases Infection Control and Employee HealthThe University of Texas MD Anderson Cancer CenterHoustonTX 77030United States

Cancer patients have unique problems associated with hepatitis C virus(HCV)infection and treatment not seen in the general *** infection poses additional challenges and considerations for the management of cancer,and vice *** infection also can lead to the development of cancer,particularly hepatocellular carcinoma and non-Hodgkin *** severely immunocompromised cancer patients,diagnosis of HCV infection requires increased reliance on RNA detection *** infection can affect chemotherapy,and delay of HCV infection treatment until completion of chemotherapy and achievement of cancer remission may be required to decrease the potential for drug-drug interactions between antineoplastic agents and HCV therapeutics and potentiation of side effects of these *** addition,hematopoietic stem cell transplant(HSCT)recipients have an increased risk of early development of cirrhosis and *** this increased risk applies to all patients regardless of cancer treatment is ***,patients with cancer may have poorer sustained virological responses to HCV infection treatment than do those without ***,not all cancer patients are candidates for HCV infection *** this article,we review the challenges in managing HCV infection in cancer patients and HSCT recipients.

关键词： Hepatitis C virus Cancer Hematopoietic stem cell transplant Chemotherapy Treatment Antiviral Pegylated interferon Ribavirin

Recent advances in semimetallic pnictogen (As, Sb, Bi) based anodes for sodium-ion batteries: Structural design, charge storage mechanisms, key challenges and perspectives

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Nano Research 2021年第11期14卷 3690-3723页

作者： Samrat Sarkar Swagata roy Yufeng Zhao Jiujun Zhang Institute for Sustainable Energy & College of Sciences Shanghai University Shanghai China

In the recent times sodium ion batteries(SIBs)have come to the forefront as an economic and resourceful alternative to lithium-ion batteries(LIBs)for powering portable electronic devices and large-scale grid *** the specific capacity,energy density and long cycle life of batteries depend upon the performance of anode materials;their quest is the ultimate need of the *** the anode materials,the semimetallic pnictogens(As,Sb,Bi)and their compounds offer high gravimetric/volumetric capacities,but suffer from undesired volume expansion and inferior electrical ***,this paper reviews the recent progress in semimetallic pnictogens as alloying anodes and their compounds mainly as conversion-alloying *** debatable sodiation mechanisms(intercalation or alloying)have been presented with emphasis on in situ/ex situ advanced characterization methods well supported by theoretical modeling and *** reviewed electrochemical reaction mechanisms,coherent structural designs and engineering provide a vital understanding of the electrochemical processes of Na^(+) ion *** existing challenges and perspectives are also presented,and several research directions are proposed from the aspects of special morphological design,employing conductive substrates,electrolyte additives and reducing particle size for technical and commercial success of SIBs.

关键词： sodium-ion battery anode pnictogen arsenic antimony bismuth

Dynamics of an autonomous food chain model and existence of global attractor of the associated non-autonomous system

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International Journal of Biomathematics 2019年第8期12卷 1-31页

作者： Jyotirmoy roy Shariful Alam Department of Mathematics Indian Institute of Engineering Science and Technology Shibpur B.GardenHowrah-711103India

In this paper,we have analyzed a tri-trophic food chain model consisting of phytoplankton,zooplankton and fish population in an aquatic ***,the pelagic water column is divided into two layers namely,the upper layer and the lower *** zooplankton population makes a diel vertical migration(DVM)from lower portion to upper portion and vice-versa to trade-off between food source and fear from predator(Fish).Here,mathematical model has been developed and analyzed in a rigorous *** from routine calculations like boundedness and positivity of the solution,local stability of the equilibrium points,we performed Hopf bifurcation analysis of the interior equilibrium point of our model system in a systematic *** is observed that the migratory behavior of zooplankton plays a crucial role in the dynamics of the model *** the upward and downward migration rates of DVM leads the system into Hopf *** upward migration rate of zooplankton deteriorates the stable coexistence of all the species in the system,whereas the downward migration rate enhance the stability of the ***,we analyze the non-autonomous version of the system to capture seasonal effect of environmental *** have shown that under certain parametric restrictions periodic coexistence of all the species of our system is ***,extensive numerical simulation has been performed to support our analytical findings.

关键词： Food chain model DVM Hopf bifurcation limit cycle periodic solution global attractor

Effect of tool rotational speed on the particle distribution in friction stir welding of AA6092/17.5 SiCp-T6 composite plates and its consequences on the mechanical property of the joint

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Defence Technology（防务技术） 2020年第2期16卷 381-391页

作者： Uttam Acharya Barnik Saha roy Subhash Chandra Saha Department of Mechanical Engineering National Institute of Technology AgartalaBarjalaJiraniaWest Tripura799046India

This study investigates the effect of tool rotational speed(TRS)on particle distribution in nugget zone(NZ)through quantitative approach and its consequences on the mechanical property of friction stir welded joints of AA6092/17.5 SiCp-T6 composite.6 mm thick plates are welded at a constant tool tilt angle of 2°and tool traverse speed of 1 mm/s by varying the TRS at 1000 rpm,1500 rpm and 2000 rpm with a taper pin profiled *** analysis shows large quantity of uniformly shaped smaller size SiC particle with lower average particle area which are homogeneously distributed in the *** fragmentation of bigger size particles has been observed because of abrading action of the hard tool and resulting shearing effect and severe stress generation due to the rotation of *** particles occupy maximum area in the matrix compared to that of the base material(BM)due to the redistribution of broken particles as an effect of *** migration of particles towards the TMAZ-NZ transition zone has been also encountered at higher TRS(2000 rpm).The microhardness analysis depicts variation in average hardness from top to bottom of the NZ,minimum for 1500 rpm and maximum for 2000 *** impact strength at 1000 rpm and 1500 rpm remains close to that of BM(21.6 J)while 2000 rpm shows the accountable *** maximum joint efficiency has been achieved at 1500 rpm(84%)and minimum at 1000 rpm(68%)under tensile *** analysis shows mixed mode of failure for BM,1000 rpm and 1500 rpm,whereas 2000 rpm shows the brittle mode of failure.

关键词： Friction stir welding Aluminium matrix composite Tool rotational speed Particle distribution Mechanical property

The role of tangential velocity in explosive initiation by fragment impact

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Defence Technology（防务技术） 2022年第12期18卷 2190-2197页

作者： Vitaly Leus roy Ceder Valentin Ognev Meir Mayseless RAFAEL Ballistic Center P.O.Box 2250HaifaIsrael Faculty of Engineering Sciences Ben-Gurion University of the NegevBeer-Sheva84105Israel

An initiation study is presented in which we examine the effect of the normal and the tangential velocity components of a fragment that impacts a covered and a bare Comp-B explosive. The study is based on calibrated numerical Lagrangian simulations using the LS-Dyna hydrocode. A special procedure was developed to present the estimated initiation point and the shock wave transition into detonation for various impact angles. The influence of the fragment strength and the steel cover thickness on the detonation threshold were also examined. The velocity threshold results are presented and used to modify the Jacobs-Roslund initiation model.

关键词： High explosive initiation Lee-tarver Jacobs-roslund Fragment