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Jalandhar, India

The Dr. B. R. Ambedkar National Institute of Technology Jalandhar, popularly known as NIT Jalandhar , is a public engineering institute located in Jalandhar, Punjab, India. It is one of the youngest of the 20 National Institutes of Technology of India. It was founded as a joint venture between the governments of Punjab and India, originally under the name Punjab Regional Engineering College, Jalandhar . Wikipedia.

Kumar R.,National Institute of Technology Jalandhar
Journal of Vibration and Acoustics, Transactions of the ASME

It is a well known fact that system parameters of the flexible structures keep on changing due to several reasons. Ordinary controllers lose their effectiveness in changed situations and do not guarantee the stability of the closed loop system. However, controllers designed based on robust control theory not only maintain the closed loop stability of the perturbed system with a large variation in system parameters but also maintain the best performance. H ∞ loop shaping controller is designed and implemented experimentally on a smart flexible beam treated with precompressed layer damping and ACLD treatment. It outperforms linear quadratic Gaussian and standard H ∞ controller both in terms of robust stability and robust performance. Relative merits and demerits of the -synthesis based controller are also discussed. Afterwards, these controllers were digitized at certain sampling frequencies and applied to the experimental flexible structure. Certain time domain parameters of the closed loop system discuss the relative superiority of these controllers which otherwise cannot be captured using frequency domain results alone. © 2012 American Society of Mechanical Engineers. Source

Accurate trajectory regulation of flexible link manipulators is a challenging task. The presence of hardware filters with the cut-off frequency near the resonant frequency cause an additional closed loop instability problem in the control system. This problem can be solved using modified Kalman filters along with certain hardware circuits called compensators. A linear quadratic Gaussian controller has been used to control the hub position. A positive position feedback (PPF) controller has been used at the piezoelectric actuators at the flexible link in the present work to minimize the end-effector vibrations. Normally the design parameters (i.e. coefficients of the numerator and denominator polynomial) of the PPF controller are selected by hit and trial. Pattern search technique has been used as an efficient design method to design these controllers which otherwise have no systematic way to design. © 2012 The Author(s). Source

Occupational noise exposure and noise-induced hearing loss (NIHL) have been recognized as a problem among workers in Indian industries. The major industries in India are based on manufacturing. There are appreciable numbers of casting and forging units spread across the country. The objective of this study is to determine the prevalence of permanent hearing threshold shift among the workers engaged in Indian iron and steel small and medium enterprises (SMEs) and compared with control group subjects. As a part of hearing protection intervention, audiometric tests were conducted at low (250-1000 Hz), medium (1500-3000 Hz), and high (4000-8000 Hz) frequencies. The occurrence of hearing loss was determined based on hearing threshold levels with a low fence of 25 dB. Comparisons were made for hearing threshold at different frequencies between the exposed and control groups using Student's t test. ANOVA was used for the comparison of hearing threshold dB at different frequencies among occupation and year of experience. A P value <0.05 was considered as statistically significant. All data were presented as mean value (SD). Over 90% of workers engaged in various processes of casting and forging industry showed hearing loss in the noise-sensitive medium and higher frequencies. Occupation was significantly associated with NIHL, and hearing loss was particularly high among the workers of forging section. The analyses revealed a higher prevalence of significant hearing loss among the forging workers compared to the workers associated with other activities. The study shows alarming signals of NIHL, especially in forging workers. The occupational exposure to noise could be minimized by efficient control measures through engineering controls, administrative controls, and the use of personal protective devices. Applications of engineering and/or administrative controls are frequently not feasible in the developing countries for technical and financial reasons. A complete hearing conservation programme, including training, audiometry, job rotation, and the use of hearing protection devices, is the most feasible method for the protection of industrial workers from prevailing noise in workplace environments in the developing countries. Source

Chandok S.,National Institute of Technology Jalandhar
Computers and Mathematics with Applications

Sufficient conditions for the existence of a common fixed point for generalized nonlinear contractive mappings are derived. As applications, some results on the set of best approximation for this class of mappings are also obtained. The proved results generalize and extend various known results in the literature. © 2011 Elsevier Ltd. All rights reserved. Source

Grover D.,National Institute of Technology Jalandhar
Archive of Applied Mechanics

In this article, the closed form expressions for the transverse vibrations of a homogenous isotropic, thermally conducting, Kelvin-Voigt type viscothermoelastic thin beam, based on Euler- Bernoulli theory have been derived. The effects of relaxation times, thermomechanical coupling, surface conditions, and beam dimensions on energy dissipation induced by thermoelastic damping in MEMS (micro-electromechanical systems) resonators are investigated for beams under clamped and simply supported conditions. Analytical expressions for deflection, temperature change, frequency shifts, and thermoelastic damping in the beam have been derived. Some numerical results with the help of MATLAB programming software in case of Silicon Nitride have also been presented. The computer-simulated results in respect of damping factor and frequency shift have been presented graphically. © 2012 Springer-Verlag. Source

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