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A review of friction models in interacting joints for durability design

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Friction 2017年第1期5卷 1-22页

作者： Zulfiqar A.kHAN vivek CHACkO Hammad NAZIR NanoCorr Energy & Modelling(NCEM)Research Department of Design & Engineering Bournemouth University Bournemouth United Kingdom

This paper presents a comprehensive review of friction modelling to provide an understanding of design for durability within interacting *** is a complex phenomenon and occurs at the interface of two components in relative *** the last several decades,the effects of friction and its modelling techniques have been of significant interests in terms of industrial *** is however a need to develop a unified mathematical model for friction to inform design for durability within the context of varying operational *** dynamic mechanisms model for the design of control systems has not incorporated friction phenomena due to non-linearity ***,the tribological performance concurrently with the joint dynamics of a manipulator joint applied in hazardous environments needs to be fully *** the dynamics and impact models used in mechanical joints with clearance have also been *** inclusion of reliability and durability during the design phase is very important for manipulators which are deployed in harsh environmental and operational *** revolute joint is susceptible to failures such as in heavy manipulators these revolute joints can be represented by lubricated conformal sliding *** presence of pollutants such as debris and corrosive constituents has the potential to alter the contacting surfaces,would in turn affect the performance of revolute joints,and puts both reliability and durability of the systems at greater risks of *** literature is identified and a review on the latest developments of the science of friction modelling is presented *** review is based on a large volume of *** in the relevant field have been identified to capitalise on for future ***,this review will bring significant benefits to researchers,academics and industry professionals.

关键词： friction dynamics joint clearance numerical models impact durability

Laparoscopic liver resection for benign and malignant liver tumors

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Hepatobiliary & Pancreatic Diseases International 2011年第1期10卷 38-42页

作者： Ashish Singhal vivek kohli Nazih Nazih Zuhdi Transplant Institute INTEGRIS Baptist Medical Center3300 NW Expressway Oklahoma CityOklahoma 73112USA

BACkGROUND:Laparoscopic liver resection is one of the most complex procedures in hepatobiliary *** the last two decades,laparoscopic liver surgery has emerged as an option at major academic *** purpose of this study is to describe the initial experience of minimally invasive liver resections at a non-academic institution. METHODS:We retrospectively reviewed medical records of patients undergoing laparoscopic liver resections between June 2006 and December 2009 at our ***, technical aspects,and outcomes of these patients are described. RESULTS:Laparoscopic liver resection was attempted in 28 *** these,27 patients underwent laparoscopic liver resection(22 total laparoscopic and 5 hand assisted)and one needed conversion to open *** patients had a benign lesion and 8 had malignant *** patients had multiple lesions in different segments requiring separate *** lesions were located in segments Ⅱ-Ⅲ(n=18), Ⅳ(n=3),Ⅴ-Ⅵ(n=9),and VII(n=1).Tumor size ranged from 1.5 cm to 8.5 *** surgical procedures included left lateral sectionectomy(n=17),left hepatectomy(n=2),sectionectomy (n=8),and local resections(n=4).Median operative time was 110 minutes(range 55-210 minutes),and the median length of hospital stay was 2.5 days(range 1-7 days).There was no perioperative *** patient developed hernia at the site of tumor extraction requiring repair at 3 months. CONCLUSIONS:Laparoscopic liver resections can be safely performed in selected patients with benign and malignant liver *** increasing experience,laparoscopic liver resections are likely to become a favorable alternative to open resection.

关键词： hepatectomy liver neoplasm liver surgery

Temperature-dependent aggregation of bio-surfactants in aqueous solutions of galactose and lactose:Volumetric and viscometric approach

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Chinese Journal of Chemical Engineering 2018年第5期26卷 1119-1131页

作者： S.Chauhan vivek Sharma Maninder kaur Poonam Chaudhary Department of chemistry Himachal Pradesh University

Modulation in the aggregation behavior of bio-surfactants （bile salts）, sodium cholate （NaC） and sodium deoxycholate （NaDC） in aqueous solutions of carbohydrates （galactose and lactose） have been investigated by measuring the density （ρ）, speed of sound （u） and viscosity （η） of the mixtures at different temperatures 293.15, 298.15, 303.15, 308.15 and 313.15 k. The density and speed of sound data have been used to calculate various volumetric and compressibility parameters such as apparent molar volume （Vφ）, isentropic compressibil- ity （κs）, apparent molar adiabatic compression （κs,φ） to get a better insight into the micellization mechanism of bile salts. Further, the viscosity data have been studied in the light of relative viscosity （ηr） and viscous relaxation time （τ）. Some derived parameters such as free volume （νf）, internal pressure （πi） and molar cohesive energy （MCE） of NaC and NaDC in aqueous solution of saccharides have also been calculated from viscosity data in con- junction with density and speed of sound values. All the calculated and derived parameters provide qualitative information regarding the nature of interactions i.e. solute-solute, solute-solvent and solvent-solvent in the solution.

关键词： Density Speed of sound Apparent molar volumelsentropic compressibility Viscosity Relative viscosity

Rare,spontaneous trans-splenic shunt and intra-splenic collaterals with attendant splenic artery aneurysms in an adult patient with compensated cirrhosis and portal hypertension

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Gastroenterology Report 2015年第2期3卷 162-166页

作者： Cyriac Abby Philips Lovkesh Anand k.N.Chandan kumar vivek kasana Ankur Arora Department of Hepatology Institute of Liver and Biliary SciencesNew DelhiIndia Department of Radiology Institute of Liver and Biliary SciencesNew DelhiIndia

We present a rare case of spontaneous trans-splenic shunt and intra-splenic collaterals in a patient with liver cirrhosis and portal *** shunt and presence of cirrhosis and portal hypertension was incidentally detected by abdominal computed tomographic imaging during evaluation for abdominal *** has been a single report on the presence of trans-splenic shunt in two children with extra-hepatic portal venous obstruction but no cases that report intra-splenic collaterals:to the best of our knowledge,this is the first reported case of spontaneous trans-splenic shunt in the presence of intra-splenic collaterals and incidental multiple splenic artery aneurysms that developed in an adult with compensated cirrhosis and portal hypertension.

关键词： cirrhosis portal hypertension portosystemic shunts collateral pathways splenomegaly

Bacterial Infections in Cirrhotic Patients in a Tertiary Care Hospital

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Journal of Clinical and Translational Hepatology 2021年第1期9卷 32-39页

作者： vivek A.Lingiah Nikolaos T.Pyrsopoulos Department of Medicine Division of Gastroenterology and HepatologyRutgers UniversityNew Jersey Medical SchoolNewarkNJUSA

Background and Aims:Patients with cirrhosis are immunocompromised and at higher risk of developing infections compared to the general *** aim of this study was to assess the incidence of infections in cirrhotic patients in a large academic liver center and investigate potential associations between infections,bacteria isolated,therapeutic regimens used,and ***:This was a retrospective chart review study,including 192 *** patients had a diagnosis of cirrhosis and were admitted to University *** collected included demographics,etiology of cirrhosis,identification of bacteria from cultures,multidrug-resistant(MDR)status,antibiotics administered,intensive care unit(ICU)admission,and patient ***:Infections were present in 105(54.6%)patients,and 60(31.2%)patients had multiple infections during a hospitalization(s)for infections.A total of 201 infections were *** tract infections(UTIs)were the most common infection(37.8%),followed by bacteremia(20.4%),pneumonia(12.9%),spontaneous bacterial peritonitis(SBP)(11.9%),abscess/cellulitis(6.0%),infectious diarrhea(6.0%),and other(5.0%).Escherichia coli was the most common bacteria isolated(13.4%),both among sensitive and MDR *** bacteria were the cause for 41.3%of all infections *** accounted for 9.5%of infections.21.9%of patients had decompensation from their infection(s)that required ICU care,and 14.6%of patients died during hospitalization or soon after ***:The incidence of infections in cirrhotic patients is much higher than in their non-cirrhotic counterparts(54.6%),even higher than prior studies *** many of these infections are caused by MDR bacteria and fungal organisms,stronger empiric antibiotics and antifungals should be considered when initially treating this immunocompromised ***,once organism sensitivities are discovered,narrowing of antibiotic regimens must occur to maintain g

关键词： Cirrhosis Bacterial infections Multidrug resistance Fungal infections

Porous perovskite films integrated with Au-Pt nanowire-based electrodes for highly flexible large-area photodetectors

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npj Flexible Electronics 2020年第1期4卷 271-278页

作者： Rohit Saraf Hua Fan vivek Maheshwari Department of Chemistry Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooONN2L 3G1Canada

Flexible,large-area,and stable perovskite photodetectors have drawn increasing widespread research attention for next-generation wearable and portable optoelectronic ***,high mechanical durability coupled with large device area and enhanced environmental stability has not been demonstrated yet to attain practical ***,a highly bendable,stable,and large-area(3 cm^(2))flexible polystyrene incorporated perovskite photodetector is *** to the formation of a porous polystyrene-perovskite composite film in a single step it allows unprecedented mechanical stability,maintaining 85%of its original photocurrent value after 10,000 bending cycles at a bending angle of 120°.Equally crucial,the solution-processed self-assembled Pt-Au nanochains were developed to provide a simple and fast method of patterning the conductive and flexible electrodes onto the filter *** optimized polystyrene-perovskite photodetector exhibits a high responsivity up to 2.73 A W^(−1),a maximum specific detectivity of 6.2×10^(13) Jones,and a superior switching ratio of 1.0×10^(4).In addition,the polystyrene-perovskite photodetector yields excellent stability under the combined stresses of moisture,ambient air,and room light,and retains 92%of its original performance for over 30 *** these results demonstrate that this work provides a facile and cost-effective approach that paves the way to develop high-performance,stable,and highly flexible optoelectronic devices.

关键词： perovskite stability bending

Pareto optimization of WEDM process parameters for machining a NiTi shape memory alloy using a combined approach of RSM and heat transfer search algorithm

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Advances in Manufacturing 2021年第1期9卷 64-80页

作者： Rakesh Chaudhari Jay J.Vora S.S.Mani Prabu I.A.Palani vivek k.Patel D.M.Parikh Department of Mechanical Engineering School of TechnologyPandit Deendayal Petroleum UniversityRaisanGandhinagar 382007India Metallurgy Engineering and Materials Science Indian Institute of Technology IndoreIndore 453552India Discipline of Mechanical Engineering Indian Institute of Technology IndoreIndore 453552India Department of Industrial Engineering School of TechnologyPandit Deendayal Petroleum UniversityRaisanGandhinagar 382007India

Machining of shape memory alloys(SMAs)without losing the shape memory effect could immensely extend their ***,the wire electric discharge machining process was used to machine NiTi—a shape memory *** experimental methodology was designed using a Box-Behnken design approach of the response surface *** effects of input variables including pulse on time,pulse off time,and current were investigated on the material removal rate,surface roughness,and *** tests were performed to check the robustness of the generated empirical *** of the process parameters was performed using a newly formulated,highly efficient heat transfer search *** tests were conducted and extended for analyzing the retention of the shape memory effect of the machined surface by differential scanning *** addition,2D and 3D Pareto curves were generated that indicated the trade-offs between the selected output variables during the simultaneous output variables using the multi-objective heat transfer search *** optimization route yielded encouraging *** objective optimization yielded a maximum material removal rate of 1.49 mm^(3)/s,maximum microhardness 462.52 HVN,and minimum surface roughness 0.11μ*** Pareto curves showed conflicting effects during the wire electric discharge machining of the shape memory alloy and presented a set of optimal non-dominant *** shape memory alloy machined using the optimized process parameters even indicated a shape memory effect similar to that of the starting base material.

关键词： Shape memory alloy(SMA) Nitinol Wire electrical discharge machining(WEDM) Heat transfer search algorithm Differential scanning calorimetry(DSC)test Shape memory effect

Optimized Tuning of LOADng Routing Protocol Parameters for IoT

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Computer Systems Science & Engineering 2023年第8期46卷 1549-1561页

作者： Divya Sharma Sanjay Jain vivek Maik Department of Electronics and Communication New Horizon College of EngineeringBengaluru560103India CMR Institute of Technology Bengaluru560037India Department of Electronics and Communication SRM Institute of Science and TechnologyKattankulathurChennai603203India

Interconnected devices and intelligent applications have slashed human intervention in the Internet of Things(IoT),making it possible to accomplish tasks with less human ***,it faces many problems,including lower capacity links,energy utilization,enhancement of resources and limited resources due to its openness,heterogeneity,limited resources and *** is challenging to route packets in such a constrained *** an IoT network constrained by limited resources,minimal routing control overhead is required without packet *** constrained environments can be improved through the optimal routing *** is challenging to route packets in such a constrained ***,this work is motivated to present an efficient routing protocol for enhancing the lifetime of the IoT *** On-demand Ad hoc Distance-vector Routing Protocol—Next Generation(LOADng)protocol is an extended version of the Ad Hoc On-Demand Distance Vector(AODV)*** AODV,LOADng is a lighter version that forbids the intermediate nodes on the route to send a route reply(RREP)for the route request(RREQ),which originated from the source.A resource-constrained IoT network demands minimal routing control overhead and faster packet ***,in this paper,the parameters of the LOADng routing protocol are optimized using the black widow optimization(BWO)algorithm to reduce the control overhead and ***,the performance of the proposed model is analyzed with the default LOADng in terms of delay,delivery ratio and *** results show that the LOADng-BWO protocol outperforms the conventional LOADng protocol.

关键词： Internet of things optimization algorithm routing protocol LOADng

A brief review on biomarkers and proteomic approach for malaria research

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Asian Pacific Journal of Tropical Medicine 2015年第4期8卷 253-262页

作者： vivek Bhakta Mathema kesara Na-Bangchang Chulabhorn International College of Medicine Thammasat University

Malaria remains as one of the significant health threat to people living in countries throughout tropical and subtropical *** studies of Plasmodium,the protozoan causing malaria,is essential for understanding its cellular structure,growth stage-specific expression of protein metabolites and complex interaction with ***-depth knowledge of the pathogen is required for identification of novel biomarkers that can be utilized to develop diagnostic tests and therapeutic antimalarial *** alarming rise in drug-resistant strains of Plasmodium has created an urgent need to identify new targets for drug development that can act by obstructing life cycle of this *** the present review,we briefly discuss on role of various biomarkers including Plnsmodium-assaciated aldolase,histidine-rich proteins and lactate dehydrogenase for diagnosis of *** we also summarize the present and future prospects of currently used techniques in proteomic approaches such as two dimensional gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight(MALDI-TOF)for diagnosis and potential identification of novel proteins for malaria research.

关键词： Biomarkers Malaria Plasmodium Proteomics