Department of Mechanical engineering
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1921
Browse
39 results
Search Results
Item Preparation of novel Zn/Gr MMC using a modified electro-co-deposition method: Microstructural and tribo-mechanical properties(Elsevier, 2021) Rathore, Jitendra S.; Belgamwar, Sachin U.Zinc is a well-suited low-cost and widely alloyed metal used in several metal matrix composites (MMCs) due to its easy availability, low melting point, excellent thermal and electrical properties. However, Zn metal alone is a low strength material which restricts its applications mostly for alloying purpose. Inclusion of graphene nano-reinforcements in Zn metal matrix could result in high strength and cost-effective nanocomposite material. In this paper, impermeable graphene nano-reinforcements are encapsulated in Zn metal matrix using a modified electro-co-deposition method followed by powder metallurgy. The uniform distribution of nano-reinforcement of graphene layers across the Zn metal matrix was achieved. The prepared nanocomposite was characterized and tested to evaluate the microstructural, morphological and tribo-mechanical properties. The graphene content in Zn matrix decreased the crystallite size and imparted the advantageous grain strengthening effect. The graphene reinforced Zn MMC sample showed a significant enhancement in the mechanical and tribological properties than that of pure Zn sample.Item Investigations on a tapered flagellated nanoswimmer propelling through a helical wave(IEEE, 2015) Rathore, Jitendra S.Flagellar propulsion, observed extensively in nature has been proposed as a means of propelling nanoswimmers. The flagellum propels either through a planar wave or through a helical wave. In the present work, an elastohydrodynamic model of a tapered flagellum propelling through a helical wave with a modified resistive force theory is used to study the propulsive dynamics of a tapered flagellum. A tapered flagellum facilitates higher velocity and efficiency as compared to a uniform diameter flagellum. The optimal size, shape parameters and material for design have been investigated for the fastest and the most efficient nanoswimmer and simulations have been carried out for the prospective biocompatible materials for designing and realization of nanoswimmers.Item Nanoswimmer Energy Transduction System: Influence of Branching(Springer, 2018-10) Rathore, Jitendra S.Nanoswimmers are of interest among researchers for their utility in propelling nanorobots to specific target for drug delivery, nanosurgery, in vivo biomedical applications such as in treatment of brain tumor and Alzheimer’s disease and similar applications. On-board powering is the major concern for locomotion of nanoswimmer and is being considered to be addressed by energy transduction mechanism to harness energy from surrounding using energy of stochastic vibrations by electrostatic, electromagnetic, and piezoelectric means. Among all, piezoelectric is emerging as a promising conversion transduction mechanism of energy harnessing for artificial nanoswimmer. In this context, in present work, an elastic flagellum of a nanoswimmer is modeled as a cantilever beam and a simulation study is done in COMSOL. The novel design of branched flagellum is conceived, modeled, and simulated. COMSOL simulation studies have been performed to compare the effect of primary and secondary branching in flagellum design in terms of stress and electric potential. Enhancement in stress and electric potential is observed approximately 20 and 15% on increasing secondary branching uniformly on the main structure of cantilever beam towards free end and keeping primary branches constant. An enhanced stress allows for larger efficiency of conversion mechanism and, therefore, it is concluded that branching of flagellum can be pivotal in increasing on-board harnessing of energy for propulsion of nanorobots.Item An evaluation of tactile frictional behavior of the wooden material(IOP, 2019) Rathore, Jitendra S.; Shrivastava, SharadSkin tribology and contact mechanics have emerged as a recent topic of research, intended to unveil the behavior of human skin. There have been variegated efforts to calculate the coefficient of friction with respect to various parameters such as sliding speed, normal load, and surface roughness. Wood and other timber products have their importance considering the ergonomically designs that have gained importance nowadays. This article shows the relation between normal load, average sliding speed and coefficient of friction (μ) of various types of woods (Rosewood, Sunmica, Teak wood and Pine wood). An experimental investigation is conducted to understand frictional behavior between human skin and different types of woods. Wooden material has been tested with the normal load having the range of 6.5N to 13N. The variation of μ has been remarked as μrosewood>μpine>μteak>μsunmica. Experimental observation shows that the rosewood has the highest COF which suggests its application where grip and strength of high order are required.With decreasing sliding speed, the relation between normal load and μ become more significant.Item Atomistic modeling and dynamic analysis of boron nitride nanotube in the presence of hexagonal defect(Elsevier, 2020) Rathore, Jitendra S.; Srivastava, SharadThe feasibility of defective Single-Walled Boron Nitride Nanotube (SW-BNNT) has been explored in the present paper employing finite element based three-dimensional atomistic modeling approach. The effect of missing of three conjugate Bsingle bondN pairs in SW-BNNT resulting in formation of hexagonal defect in SW-BNNT on resonance frequency has been analyzed in the present paper. Two different types of SW-BNNT i.e., armchair (5, 5) and Zigzag (5, 0) BNNT of 5 nm length have been analyzed for cantilever and bridged configuration. Further, present work explores the effect of position of defect on resonance frequency in SW-BNNT. The simulation results revels that resonance frequency decreases due to presence of defect and this reduction in frequency increases if the position of defect moves towards free end in the case of cantilever configuration. On the contrary for bridge configuration the resonance frequency decreases continuously if position of defect moves from fixed end to midpoint. Thus it can be concluded that due to presence of defect in nanotube, the resonance frequency decreases and suggests that stiffness is more dominating than mass of nanotube.Item Hybrid approach for dynamic analysis of single-walled Boron Nitride Nanotube (SW-BNNT) in presence of vacancy defect(Elsevier, 2021) Srivastava, Sharad; Rathore, Jitendra S.The appropriateness of single walled Boron Nitride Nanotube for recognition of mass as little as of the request for femtogram level (10–18 fg) in nearness of centre found point defect has been investigated through current paper using 3-dimensional atomistic structure approach based on finite element method. The impact of shifting mass in nearness of defect on frequency for armchair (5,5) Boron Nitride Nanotube has been analysed for bridge setup. Considering FEM approach the mass affectability for bridge design is seen as higher when contrasted with cantilever one. The experimental results delight that shorter length of BNNT with bridge arrangement is appropriate for detecting mass as little as of the request for femtogram level when mass is available on focus.Item Efficacy of ANN and ANFIS as an AI Technique for the Prediction of COF at Finger Pad Interface in Manipulative Tasks(Springer, 2023-03) Rathore, Jitendra S.; Srivastava, SharadCurrent work intends to compare the modelling ability of two popular artificial intelligence (AI) techniques, namely artificial neural network (ANN) and adaptive-neuro fuzzy inference system (ANFIS). Outcome of study is useful in prediction and further optimization of the coefficient of friction in the design of assistive devices for an ergonomics and comfort of the user. Experiments were conducted using Taguchi L16 design of experiments (DOE). Total of 16 experimental runs were conducted. Two extrinsic factors normal load (2, 4,6, & 8 N) and sliding velocity (4, 6, 8 & 10 cm/s) that affect the finger pad friction are taken as input variables, while coefficient of friction (COF) between finger pad and the stainless steel (SS) probe is the output variable. ANN with 2 inputs, 10 hidden, and 1 output layer is trained by three algorithms, viz. Levenberg–Marquardt (R2 = 0.96), Bayesian Regularization (R2 = 0.93), and Scaled Conjugate Gradient (R2 = 0.98) based on the correlation coefficient. Although, both the techniques highlight significant predictability and accuracy, ANFIS results shows overfitting of the data. Hence, ANN technique is relatively better than ANFIS.Item Experimental investigation of biomimetic propulsion through a scaled up branched flagellated artificial nanoswimmer(Taylor & Francis, 2020-05) Rathore, Jitendra S.Locomotion of bacteria in fluid at small scale is accomplished by cilia and flagella present on its surface. In the present study, existence of cilia on Paramecium surface is mimicked to design scaled-up swimmer rather than utilising its biological function. In the present study, the branches (cilia) on flagella (Paramecium) is employed for designing of tail of an artificial nanoswimmer and experiments are performed at scaled-up level in silicon oil medium to maintain low Reynolds number. The effects of branches on generation of thrust force are investigated by fabricating the branched flagella using flexible polydimethylsiloxane biocompatible material suitable for human body and biological applications. The resulting data are quantitatively compared through statistical analysis. In the present research work, various designs of branched flagellated swimmer are fabricated by varying the number of branches and spacing between branches. Enhancement in thrust force is observed approximately 24% when number of branches is increased from 8 to 28. Therefore, it is concluded that branches on flagella play significant role in enhancement of thrust force for propelling nanoswimmer. Spacing between 8 branches flagella is also varied from 5 to 15 mm and percentage increase in thrust force is observed as 8.1%.Item Nonlinear vibration analysis of curvy single-walled boron nitride nanotube using mathematical modeling for dynamic responses(World Scientific, 2023-08) Rathore, Jitendra S.; Shrivastava, SharadThis work explores the feasibility of nonlinear behavior of doubly clamped single-walled boron nitride nanotube (SW-BNNT)-based nanoresonator. A nonlinear mathematical model of wavy SW-BNNT has been developed for analyzing the geometrical nonlinearity. Dynamic responses of nonlinear model have been analyzed for different waviness factors varying from 0.01 to 0.06 using various tools like time series, phase space, Poincaré map and Fast Fourier Transforms (FFTs). For the analysis, 20nm length of SW-BNNT has been considered. It has been observed from nonlinear analysis, that for responses with a lower value of waviness (e.g., 0.01) for 20nm long BNNT, the system’s nature loses its periodicity and shows onset of chaos with dense spectrum in Poincaré maps and irregular pattern in time response. Thus, it is concluded that chaotic response with a less strange attractor has been observed when waviness is 0.01. It is also concluded that, with increase in waviness factor from 0.02 to 0.06, the system showed the multi-periodic response with 2-T, 3-T and 4-T periods. The dynamic responses with varying waviness showed that the system behavior is changing from chaotic to periodic. This change in periodicity is one of the characteristics of chaotic solution.Item Cupronickel composites: An overview of recent progress and applications(CRC Press, 2023) Rathore, Jitendra S.; Belgamwar, Sachin U.This study presents an overview of the various types of composites and their fabrication methods. The study then presents a summary discussion on the fabrication of various cupronickel composites using electrodeposition method and powder metallurgy method. Cupronickel composites are fabricated by adding reinforcing material into the cupronickel alloy matrix, which has led to a significant interest due to their superior hardness, wear resistance, tensile strength, macrofouling resistance, corrosion resistance anti-bacterial properties. Due to these properties, cupronickel composites are employed in various engineering applications such as condenser tubes, cooling circuits, heat exchangers, microelectronics, and condensers. Based on the critical assessment of the literature, existing challenges with possible solutions and future research opportunities were discussed.