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Powder mixed electrochemical discharge process for micro machining of C103 niobium alloy

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Defence Technology（防务技术） 2023年第8期26卷 84-101页

作者： Niladri Mandal Nitesh kumar alok kumar Das Defence Research&Development Laboratory(DRDL)-DRDO HyderabadIndia Department of Mechanical Engineering Indian Institute of Technology(ISM)DhanbadIndia

This work demonstrates the viability of the powder-mixed micro-electrochemical discharge machining(PMECDM) process to fabricate micro-holes on C103 niobium-based alloy for high temperature *** processes are involved simultaneously *** erosion,chemical etching,and abrasive grinding for removal of material while the classical electrochemical discharge machining process involves double actions *** erosion,and chemical *** powder-mixed electrolyte process resulted in rapid material removal along with a better surface finish as compared to the classical microelectrochemical discharge machining(MECDM).Further,the results are optimized through a multiobjective optimization approach and study of the surface topography of the hole wall surface obtained at optimized *** the selected range of experimental parameters,PMECDM shows a higher material removal rate(MRR) and lower surface roughness(R_(a))(MRR:2.8 mg/min and R_(a) of 0.61 μm) as compared to the MECDM process(MRR:2.01 mg/min and corresponding Raof 1.11 μm).A detailed analysis of the results is presented in this paper.

关键词： Micro-electrochemical discharge machining C103 niobium alloy Surface integrity Material removal rate Hybrid powder mixed ECDM

Experimental investigation for machinability aspects of graphene oxide/carbon fiber reinforced polymer nanocomposites and predictive modeling using hybrid approach

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Defence Technology（防务技术） 2021年第5期17卷 1671-1686页

作者： Jogendra kumar Rajesh kumar verma Department of Mechanical Engineering Madan Mohan Malaviya University of TechnologyGorakhpur273010India

This article explores the drilling behavior of polymer nanocomposites reinforced by Graphene oxide/Carbon fiber using a hybrid method of Grey theory and Principal component analysis(GR-PCA).An online digital dynamometer was employed for the evaluation of Thrust Force and *** image processing technique computes the *** surface methodology(RSM)considers the parameters,namely,drilling speed(S),feed rate(F),Graphene Oxide wt.%(G)in designing the experimentation *** component analysis(PCA)was used to tackle the response priority weight during the combination of multiple *** of variance(ANOVA)scrutinized the influence of parameters and intended the regression models to predict the ***-PCA evaluated the optimal parametric setting and remarked that feed rate acts as the most predominant *** higher feed rate and wt.%of G is responsible for surface damages like fiber pull-out,fiber fracture and cracks.A significant improvement in drilling responses has been obtained and also validates through confirmatory test and microstructure investigations.

关键词： Graphene oxide Polymer Carbon fiber RSM ANOVA GR-PCA

Dual-Core Photonic Crystal Fiber Plasmonic Refractive Index Sensor: A Numerical Analysis

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Photonic Sensors 2019年第2期9卷 151-161页

作者： alok kumar PAUL Ajay Krishno SARKAR Department of Electrical & Electronic Engineering Rajshahi University of Engineering & Technology Rajshahi-6204 Bangladesh

A numerical analysis on dual core photonic crystal fiber (DC-PCF) based surface plasmon resonance (SPR) refractive index sensor is presented. The guiding parameters and required sensing performances are examined with finite element method (FEM) based software under MATLAB environment. According to simulation, it is warranted that the proposed refractive index sensor offers the maximum amplitude sensitivity of 554.9 refractive index unit (RIU-1) and 636.5 RIU 1 with the maximum wavelength sensitivity of 5800nm/RIU and 11 500nm/RIU, and the sensor resolutions of 1.72 ×10^-5RIU and 8.7× 10^-6 RIU, at analyte refractive index (RI) of 1.40 for x- and y-polarized modes, respectively. As the sensing performance in different wavelength ranges is quite high, the proposed sensor can be used in simultaneous detection for different wavelength ranges. Therefore, the proposed device is of a suitable platform for detecting biological, chemical, biochemical, and organic chemical analytes.

关键词： Photonic crystal fiber biosensor refractive index sensor finite element method plasmonic material

Optimal ordering policy for short life-cycle products under credit financing with dynamic adoption in supply chain

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Journal of Management Analytics 2019年第3期6卷 269-301页

作者： Udayan Chanda alok kumar Department of Management BITS PilaniPilaniIndia FORE School of Management New DelhiIndia

Traditional inventory models are mostly ignorant of the life cycle dynamics of a technology product;hence,they often fail to identify different dimensions of inventory *** paper attempts to investigate the relationship between adoption behavior of customers using life cycle dynamics and associated trade credit policies in order to optimize the total inventory *** demand model used in this paper treats sales as a function of awareness diffusion and *** is considered as a function of feedback effects from users/***’s optimal strategies for short life cycle product under credit financing were determined ***,numerical examples have been used to support the theoretical *** results have further been used to gain some managerial insights.

关键词： inventory stage-wise diffusion unfavorable information short life cycle trade credit

Battery energy storage-based system damping controller for alleviating sub-synchronous oscillations in a DFIG-based wind power plant

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Protection and Control of Modern Power Systems 2023年第2期8卷 260-277页

作者： Neevatika verma Narendra kumar Rajeev kumar Department of Electrical Engineering Delhi Technological UniversityNew DelhiIndia Electrical Engineering Department Jamia Millia IslamiaNew DelhiIndia Electrical and Electronics Engineering Department KIET Group of InstitutionsGhaziabadIndia

This paper presents the issue of the Sub-synchronous resonance(SSR)phenomenon in a series compensated DFIG-based wind power plant and its alleviation using a Battery Energy Storage-based Damping Controller(BESSDCL).A supplementary damping signal is developed considering the angular speed deviation and is incorporated into the BESS control ***-area Measurement System data is used to determine the angular speed deviation.A lin-earized system model is developed to perform eigenvalue analysis,and to detect and examine unstable SSR *** variation of wind speed and three-phase fault are also taken into consideration to validate the robustness of the *** further verify the efficacy of the proposed damping controller,time-domain simulations are performed using MATLAB/*** application of the proposed BESSDCL stabilizes all the unstable system modes effectively at wind speeds of 7 m/s,9 m/s,and 11 m/s,and at 40%,50%,and 60%series compensation levels,as well three-phase fault conditions.

关键词： Battery energy storage system Damping controller Doubly-fed induction generator(DFIG) Series

Influence of rooftop telecommunication tower on set back-step back building resting on different ground slopes

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 351-362页

作者： Amit Thakur Deepankar kumar Ashish Surender kumar verma Civil Engineering Department Kurukshetra University Civil Engineering Department Maharaja Agrasen Institute of Technology Maharaja Agrasen University Civil Engineering Department Punjab Engineering College (Deemed to be University)

In the hilly region due to scarcity of the plain area, buildings like set back-step back are more often used and also as a big surge in the telecommunication industries, rooftop tower adaptation is very common story nowadays. In the present study an analogy has been drawn to find out the influence of the rooftop telecommunication tower on the setback-step back building resting on ground at 20° and 30° slopes. A dynamic analysis has been performed and compared on the 4 legged angled section telecommunication tower which is located on the roof top of set back-step back building by varying positions of tower with the existing host structure built up on ground slope of 20° and 30° in both directions(X and Y).

关键词： rooftop telecommunication tower set back-step back building response spectrum analysis steel, RC frame, earthquake SAP2000

Polyaxial strength criterion and closed-form solution for squeezing rock conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 507-515页

作者： Rupesh kumar verma Sarvesh Chandra Department of Civil Engineering Indian Institute of Technology KanpurKanpur208016India

In this paper,a nonlinear strength criterion is proposed using the average of intermediate(σ2)and minor(σ3)principal stresses in place of σ3 in Ramamurthy(1994)’s strength *** proposed criterion has the main advantages of negligible variation of strength parameters with confining stress and ability to link with conventional strength ***,a new closed-form solution based on the proposed criterion is derived and validated for Chhibro Khodri ***,analytical solutions including Singh’s elastoplastic theory,Scussel’s approach,and closed-form solutions based on conventional and modified Ramamurthy(2007)criteria are compared with the results of proposed *** is shown that the in situ squeezing pressure predictions made by the proposed approach are more ***,a parametric study of the present analytical solution is carried out,which displays explicit dependency of tunnel stability on internal support pressure and tunnel *** influence of tunnel geometry is observed to be dependent on the applied support pressure.

关键词： Intermediate principal stress Squeezing pressure Closed-form solution Polyaxial strength criterion

Slip flow of micropolar fluid through a permeable wedge due to the effects of chemical reaction and heat source/sink with Hall and ionslip currents:an analytic approach

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Propulsion and Power Research 2020年第3期9卷 289-303页

作者： Khilap Singh alok kumar Pandey Manoj kumar Department of Mathematics Statisticsand Computer ScienceG.B.Pant University of Agriculture and TechnologyPantnagar263145UttarakhandIndia Department of Mathematics Graphic Era Deemed to Be UniversityDehradun248002UttarakhandIndia

This study focuses on the combined impact of heat source/sink and chemical reaction on slip flow of micropolar fluid through a permeable wedge in the existence of Hall and ion-slip *** governing highly non-lincar PDEs were altered into a set of non-linear coupled ODEs by using similarity *** transformation method(DTM)has been implemented in transformed ODEs *** comparison with previous literatures was performed and the data of this study was found to be in accordance with each *** analytical solutions for skin-friction coefficients(surface drag forces),Nussclt and Sherwood numbers are depicted through graphs and *** study of boundary layer flow over a wedge surface plays an imperative role in the field of aerodynamics,heat exchanger,ground water pollution and geothermal system etc.

关键词： Chemical reaction Differential transformation method(DTM) Hall current and ion slip Heat source/sink Micropolar fluid Slip velocity

Numerical solution of micropolar fluid flow via stretchable surface with chemical reaction and melting heat transfer using Keller-Box method

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Propulsion and Power Research 2021年第2期10卷 194-207页

作者： Khilap Singh alok kumar Pandey Manoj kumar Department of Mathematics Statistics and Computer ScienceG.B.Pant University of Agriculture and TechnologyPantnagarUttarakhand263145India Department of Mathematics Graphic Era Deemed to be UniversityDehradunUttarakhand248002India

The main theme of this research is to find the numerical results of stagnation point flow of micropolar fluid over a porous stretchable surface due to the physical effects of internal heat generation/absorption,melting heat transfer and chemical reaction via Keller-Box method(KBM).The graphs and tables are depicted and explained for various embedded *** range of melting heat transfer parameter is 0≤M≤3,the range of chemical reaction parameter is 0≤K_(r)≤1 whereas the values of space-temperature dependent heat source/sink parameters lies in-0:4≤Q≤0:4 and-2≤Q*≤*** upshots of the current problem illustrate that at fluid-solid interface,rate of HMT(heat and mass transfer)declined on escalating the values of stretching ***,as the values of internal heat source/sink parameter increases,heat transfer rate declines at fluid-solid interface.

关键词： Chemical reaction Implicit finite difference Keller-Box method(KBM) Internal heat generation/absorption Heat and mass transfer(HMT) Melting heat transfer Porous medium