Browsing by Author "Srivastava, Sharad"

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Atomistic modeling and dynamic analysis of boron nitride nanotube in the presence of hexagonal defect
(Elsevier, 2020) Rathore, Jitendra S.; Srivastava, Sharad
The 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.
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, Sharad
Current 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.
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.
Micro Structure and Characterization of Hydroxyapatite Coating (HAP) by Rod Flame Spray Process
(ASM International, 2017-06) Srivastava, Sharad
Hydroxyapatite (HAP) is available in powder form for plasma spraying. HAP powder was fabricated indigenously in the Rod form of diameter 4.17mm. This rod was sprayed with the help of MEC make Rodojet 9810 (flame spray process). Rodojet parameter were optimised for HAP rod. Crystallinity and purity level of HAP rod was measured. XRD and SEM were used to analysed the microstructure of rod and coating. The microstructure, mechanical properties of the coating were investigated, and measure the Ca/P ratio of coating and rod. The micro-hardness and elastic modules were determined by indentation tests and bond strength was determined by tensile test. The results showed that the microstructure, mechanical properties was observed same as in plasma spray process. Porosity was observed more than 15%. The bond strength of coating was observed 20 MPa. Scratch test was done to measure the cohesive strength of coating. This new experiments play an important role for reduction the cost of the HAP powder coating.