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Finite Deformation, Finite strain Nonlinear Dynamics and Dynamic Bifurcation in TVE solids with Rheology

Applied Mathematics 2024年第1期15卷 108-168页

作者： karan s. surana sri sai Charan Mathi Department of Mechanical Engineering University of Kansas Lawrence US

This paper presents a mathematical model consisting of conservation and balance laws (CBL) of classical continuum mechanics (CCM) and ordered rate constitutive theories in Lagrangian description derived using entropy inequality and the representation theorem for thermoviscoelastic solids (TVEs) with rheology. The CBL and the constitutive theories take into account finite deformation and finite strain deformation physics and are based on contravariant deviatoric second Piola-Kirchhoff stress tensor and its work conjugate covariant Green’s strain tensor and their material derivatives of up to order m and n respectively. All published works on nonlinear dynamics of TVEs with rheology are mostly based on phenomenological mathematical models. In rare instances, some aspects of CBL are used but are incorrectly altered to obtain mass, stiffness and damping matrices using space-time decoupled approaches. In the work presented in this paper, we show that this is not possible using CBL of CCM for TVEs with rheology. Thus, the mathematical models used currently in the published works are not the correct description of the physics of nonlinear dynamics of TVEs with rheology. The mathematical model used in the present work is strictly based on the CBL of CCM and is thermodynamically and mathematically consistent and the space-time coupled finite element methodology used in this work is unconditionally stable and provides solutions with desired accuracy and is ideally suited for nonlinear dynamics of TVEs with memory. The work in this paper is the first presentation of a mathematical model strictly based on CBL of CCM and the solution of the mathematical model is obtained using unconditionally stable space-time coupled computational methodology that provides control over the errors in the evolution. Both space-time coupled and space-time decoupled finite element formulations are considered for obtaining solutions of the IVPs described by the mathematical model and are presented i

关键词： Thermoviscoelasticity Rheology Memory Finite strain Finite Deformation Nonlinear Dynamics Dynamic Bifurcation Ordered Rate Theories

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Fresh or aged:short time anodization of titanium to understand the influence of electrolyte aging on titania nanopores

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Journal of Materials science & Technology 2022年第24期119卷 245-256页

作者： Tianqi Guo saso Ivanovski karan Gulati The University of Queensland School of DentistryHerston QLD 4006Australia

Electrochemical anodization(EA)is a simple and cost-effective technique to fabricate controlled nanostructures on Ti substrates,such as TiO_(2)nanotubes and *** aging of organic EA electrolytes(repeated EA using non-target Ti before EA of target Ti)is recognized to influence the characteristics of the anodized ***,there is limited information about how surface topography and electrolyte aging dictate the formation and characteristics of the anodized *** the current study,short-time EA(starting at 10 s)of micro-machined Ti substrates was performed with electrolytes of various ages(fresh/unused,15 h aged and 30 h aged),followed by evaluation of the TiO_(2)nanopores(TNPs)characteristics in terms of topography,chemistry,stability and protein *** results showed that aligned TNPs were obtained earlier(120 s)with fresh electrolyte as compared to the aged electrolyte EA(600 s).Interestingly,TNPs fabricated using fresh electrolyte(at lower EA times)showed favorable wettability,protein adhesion capacity and mechanical properties compared with aged electrolyte *** findings of the study demonstrate how nanopore formation differs between fresh and aged electrolytes when performing EA of micro-machined Ti,which provides an improved understanding of electrolyte aging and its influence on anodized nanostructures.

关键词： Titanium Titania nanopores Electrochemical anodization Electrolyte aging surface modification

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Development of prosthetic arm using body actioned sEMG signals

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Journal of Innovative Optical Health sciences 2016年第6期9卷 58-65页

作者： karan Veer Tanu sharma Amod Kumar EIED Department Thapar UniversityPatialaIndia CsED Department Global College of EngineeringKhanpur KuiIndia Chief scientist CSIO-CSIRChandigarhIndia

People's working capability is badly affected when they sufer an amputated *** replacements with prosthetic devices to get a satisfactory level of performance for essential functions with the currently available prosthetic technology are very *** arm prostheses are becoming popular because they are operated by a natural contraction of intact ***,sEMG based artifdal arm was *** system cousists of diferent electronic and mechanical assemblies for operation of hand utilizing microcontroller in order to have minimum signal loss during its *** the hep of relay switching connected to low power DC motor,system is capable of opening and closing of grip according to individual wish.

关键词： sEMG electrodes variable gripping myoelectric controls electronic interface signals processing.

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Plasma Pulse Technology: An uprising EOR technique

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Petroleum Research 2018年第2期3卷 180-188页

作者： karan Patel Manan shah Anirbid sircar school of Petroleum Technology Pandit Deendayal Petroleum UniversityGandhinagarGujaratIndia

Conventionally oil recovery factor is too low,which leaves great prospects for the application of enhanced oil recovery(EOR)methods to increase recovery *** methods are capital intensive and few are environmentally *** the paper discusses on the alternate enhanced oil recovery technique which has tremendous potential to curb the challenges of conventional EOR *** pulse technology(PPT)aided EOR treatment is administered with an electric wireline conveyed plasma pulse generator tool that is run in the well and positioned alongside the *** energy stored in the generator's capacitors,a plasma arc is created that emits a tremendous amount of heat and pressure for a fraction of a *** in turn creates a broad band of hydraulic impulse acoustic waves that are powerful enough to clean perforations and near wellbore *** waves continue to resonate deep into the reservoir,exciting the fluid molecules and increasing the reservoirs natural resonance to the degree that it can break larger hydrocarbon molecules to smaller one and simultaneously reducing adhesion tension which results in increased mobility of *** plasma pulse technology has been successfully used on production as well as injection *** has been used often as a remedial procedure to increase well's productivity that has been on production for a period of *** paper throws light on fundamentals of this advancing plasma pulse technology,contrasting it with recent EOR *** of treatment in increasing oil recovery,it's applicability to different reservoir types and results achieved so far are also covered in the paper.

关键词： Enhanced oil recovery Plasma pluse technology Reservoir natural resonance Effective viscosity Oil production Reservoir deliverability and intake

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structural and optical verification of residual strain effect in single crystalline CdTe nanowires

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Nano Research 2014年第2期7卷 228-235页

作者： Liubing Huang siyuan Lu Paichun Chang karan Banerjee Robert Hellwarth Jia Grace Lu Department of Physics and Astronomy Department of Electrical Engineering University of Southern California Los Angeles CA90089 USA IBM Thomas.I. Watson Research Center 1101 Kitchawan Road Yorktown Heights NY 10598 USA

single crystalline CdTe nanowires have been synthesized using Au-catalyzed chemical vapor deposition. X-ray diffraction reveals the existence of non- negligible inhomogeneous compressive strain in the nanowires along the 〈111〉 growth direction. The effect of the strain on the electronic structure is manifested by the blue-shifted and broadened photoluminescence spectra involving shallow donor/acceptor states. such residual strain is of great importance for a better understanding of the optical and electrical behaviors of various semiconductor nanomaterials as well as for device design and applications.

关键词： CdTe nanowire single crystalline chemical vapor deposition residual strain photoluminescence

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Implications of future climate change on crop and irrigation water requirements in a semi-arid river basin using CMIP6 GCMs

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Journal of Arid Land 2022年第11期14卷 1234-1257页

作者： Kunal karan Dharmaveer sINGH Pushpendra K sINGH Birendra BHARATI Tarun P sINGH Ronny BERNDTssON Department of Water Engineering and Management Central University of JharkhandBrambeRanchi 835205India symbiosis Institute of Geo-informatics Symbiosis International(Deemed University)Pune 411016India Water Resources systems Division National Institute of HydrologyRoorkee 247667India Division of Water Resources Engineering&Centre for Advanced Middle Eastern studies Lund UniversityLund Box 11722100Sweden

Agriculture faces risks due to increasing stress from climate change,particularly in semi-arid *** of understanding of crop water requirement(CWR)and irrigation water requirement(IWR)in a changing climate may result in crop failure and socioeconomic problems that can become detrimental to agriculture-based economies in emerging nations *** research in CWR and IWR has largely focused on large river basins and scenarios from the Coupled Model Intercomparison Project Phase 3(CMIP3)and Coupled Model Intercomparison Project Phase 5(CMIP5)to account for the impacts of climate change on *** basins,however,are more susceptible to regional climate change,with more significant impacts on *** study estimates CWRs and IWRs for five crops(sugarcane,wheat,cotton,sorghum,and soybean)in the Pravara River Basin(area of 6537 km^(2))of India using outputs from the most recent Coupled Model Intercomparison Project Phase 6(CMIP6)General Circulation Models(GCMs)under shared socio-economic Pathway(ssP)245 and ssP585 *** increase in mean annual rainfall is projected under both scenarios in the 2050s and 2080s using ten selected CMIP6 *** for all crops may decline in almost all of the CMIP6 GCMs in the 2050s and 2080s(with the exceptions of ACCEss-CM-2 and ACCEss-EsM-1.5)under ssP245 and ssP585 *** availability of increasing soil moisture in the root zone due to increasing rainfall and a decrease in the projected maximum temperature may be responsible for this decline in ***,except for soybean and cotton,the projected IWRs for all other three crops under ssP245 and ssP585 scenarios show a decrease or a small increase in the 2050s and 2080s in most CMIP6 *** findings are important for agricultural researchers and water resource managers to implement long-term crop planning techniques and to reduce the negative impacts of climate change and associated rainfall variability to avert crop failure and agricultural

关键词： climate change crop water requirement irrigation water requirement CMIP6 GCMs emission scenario Pravara River Basin

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A rapid solid-state synthesis of electrochemically active Chevrel phases （Mo6T8; T = s, se） for rechargeable magnesium batteries

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Nano Research 2017年第12期10卷 4415-4435页

作者： Partha saha Prashanth H. Jampani Moni K. Datta Daeho Hong Bharat Gattu Prasad Patel karan s. Kadakia Ayyakkannu Manivannan Prashant N. Kumta Department of Bioengineering Swanson School of Engineering University of Pittsburgh Pittsburgh PA 15261 USA U.s. Department of Energy National Energy Technology Laboratory Morgantown WV26507 USA Mechanical Engineering and Materials science Swanson School of Engineering University of Pittsburgh Pittsburgh PA 15261 USA Chemical and Petroleum Engineering Swanson School of Engineering University of Pittsburgh Pittsburgh PA 15261 USA school of Dental Medicine University of Pittsburgh Pittsburgh PA 15251 USA Center for Complex Engineered Multifunctional Materials University of Pittsburgh Pittsburgh PA 15261 USA Present address: Department of Ceramic Engineering Nationallnstitute ofTechnology-Rourkela Odisha-769008 India

High energy mechanical milling （HEMM） of a stoichiometric mixture of molybdenum and metal chalcogenides （CuT and MOT2; T = s, se） followed by heat treatment at elevated temperatures was successfully applied to synthesize Chevrel phases （Cu2Mo6T8; T = s, se） as positive electrodes for rechargeable magnesium batteries. Differential scanning calorimetry （DsC）, thermogravimetric analyses （TGA）, X-ray diffraction （XRD）, and scanning electron microscopy （sEM） were used to understand the phase formation following milling and heat treatment. Cus and Mo were observed to react at 714-800 K and formed an intermediate ternary Chevrel phase （Cu1.83Mo3s4）, which further reacted with residual Mo and Mos2 to form the desired Cu2Mosss. Quantitative XRD analysis shows the formation of a -96%-98% Chevrel phase at 30 min following the milling and heat treatment. The electrochemical performance of de-cuprated Mo6s8 and Mo6ses phases were evaluated by cyclic voltammetry （CV）, galvanostatic cycling, and electrochemical impedance spectroscopy （EIs）. The results of the CV and galvanostatic cycling data showed the expected anodic/cathodic behavior and a stable capacity after the first cycle with the formation of MgxMo6T8 （T = s, se; 1 ≤ x 〈 2）. EIs at -0.1 V intervals for the Mo6ss electrode during the first and second cycle shows that partial Mg-ion trapping resulted in an increase in charge transfer resistance Re. In contrast, the interfacial resistance Ri remained constant, and no significant trapping was evident during the galvanostatic cycling of the Mo6,se8 electrode. Importantly, the ease of preparation, stable capacity, high Coulombic efficient35 and excellent rate capabilities render HEMM a viable route to laboratory-scale production of Chevrel phases for use as positive electrodes for rechargeable magnesium batteries.

关键词： magnesium battery Chevrel phase high energy mechanicalmilling electrochemical properties

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Closed Loop Hydraulic system and Its Effect on Actuator Design

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Journal of Marine science and Application 2021年第2期20卷 333-342页

作者： karan sotoodeh Manifold&Valve Engineering Baker Hughes0483 OsloNorway

Hydraulic systems provide a clean and stable supply of hydraulic fluid for subsea valves and actuators installed on the subsea bed in subsea production *** control systems are used for contemporary subsea fields instead of installing the control system on *** all-electric subsea systems are state-of-the-art with benefits such as health,safety,and environment improvement,as well as efficiency and lower cost,hydraulic systems are still used for the development of many subsea *** of the main questions in the selection of a subsea hydraulic field is whether to choose an open or closed loop hydraulic *** main characteristic of an open loop hydraulic system is that the hydraulic fluid is discharged into the marine environment during the actuation of the subsea ***,the hydraulic fluid is returned to the topside facilities through an umbilical system in a closed loop *** that closed loop systems are more eco-friendly,the main question in this research is to examine the effect of the actuator connection of the closed loop system on actuator *** cases of actuated valves connected to a closed loop system are analyzed in this *** first is a 71/*** slab gate valve in the pressure class of 517 bar with a linear spring return fail-safe close(FsC)actuator located on a manifold *** data indicates that the piston rod and cylinder diameter of the FsC linear actuator should be increased by some millimeters due to the accumulation of hydraulic oil at the bottom of the *** hydraulic oil in the closed loop system helps in closing the actuator and spring force,so the spring constant and torque should be reduced as a *** second case involves a *** ball valve in the pressure class of 517 bar with a double-acting fail-as-is rack and pinion *** conclusion in this case is to avoid making any change in the design of double-acting actuator in connection to the closed loop sy

关键词： subsea Hydraulic system Valves and actuators Closed loop hydraulic Hydraulic actuators Actuators design modification Emission reduction

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Vascular dysfunction in Alzheimer’s disease: a biomarker of disease progression and a potential therapeutic target

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Neural Regeneration Research 2020年第6期15卷 1030-1032页

作者： karan Govindpani Chitra Vinnakota Henry J.waldvogel Richard L.Faull Andrea Kwakowsky Centre for Brain Research Department of Anatomy and Medical Imaging Faculty of Medical and Health Sciences University of Auckland

Alzheimer’s disease(AD)is a progressive neurodegenerative disorder and the predominant form of *** its initial description by Alois Alzheimer in 1906,several advances have been made in our understanding of the progression of the disease and its clinical consequences,yet the underlying etiology remains *** the stereotyped patterns of cortical and hippocampal neuronal loss and the progressive degeneration of key neurotransmitter pathways,research has traditionally been focused on factors affecting neuronal viability,including the contribution of glial dysfunction to neuronal *** a clinical perspective,the fruits of this work have been *** pathological markers of the disease,includingβ-amyloid(Aβ)plaque formation and tau hyperphosphorylation,have yielded no effective therapies,highlighted by the recent discontinuations of several high profile Aβimmunotherapy *** few current symptomatic therapies for AD are predicated on the amelioration of cholinergic or glutamatergic *** from underscoring the inadequacy of current therapeutic approaches,this also points to the importance of alternative contributors to AD *** recent years,there has been a growing appreciation for the multimodal and multifactorial nature of the condition;the case for combinatorial therapies is thus strong.

关键词： Alzheimer degeneration dysfunction

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All-Electric subsea Control systems and the Effects on subsea Manifold Valves

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Journal of Marine science and Application 2020年第3期19卷 465-472页

作者： karan sotoodeh Valve Engineering Baker Hughes0477 OsloNorway

subsea development is moving constantly toward simplification,digitalization,and cost-out strategies because the exploration and production of hydrocarbons are moving toward deeper and remote sea water *** of all-electric subsea technology instead of hydraulic technology is growing and will be the future of subsea systems due to the former’s environmental and functional advantages and reduced *** benefits of all-electric subsea systems are health,safety,and environment(HsE)and improved reliability,flexibility,and functionality compared with traditional hydraulic-electrical *** electrohydraulic technology for a typical subsea system,hydraulic and electric actuators,and subsea manifold valves including valve types and selection philosophy have been reviewed in this *** major worldwide oil companies such as Equinor and schlumberger have successful experiences with subsea electric *** the benefits of all-electric technology especially in terms of cost and HsE,as well as successful experiences of two major oil companies,further research in this area is *** of the gaps in existing reviewed literature is the effect of using all-electric actuators for manifold ***,three main questions related to electric actuator selection,requirement of safety integrity level(sIL),and effect of using electric actuators on manifold valve selection have been addressed and *** hydraulic actuated manifold valves from nine past subsea projects in different parts of the world,mainly Africa and Australia,have been selected for the analysis of all-electric *** show that 93%of the valves require spring-return electric actuators,whereas 7%can be operated with conventional electric actuators without any *** manifold valves do not require sIL certification because they are not connected to an emergency shut down *** the electric actuators to the manifold valve will not change the valve

关键词： subsea oil and gas Production Manifold Industrial valves Electric actuators Oil and gas Offshore Marine environment

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