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Sharma, Abhay
- India's Global Impact is Taking its Due Course
Authors
1 CSIR-Institute of Genomics and Integrative Biology, Sukhdev Vihar, Mathura Road, New Delhi 110 025, IN
Source
Current Science, Vol 109, No 10 (2015), Pagination: 1762-1762Abstract
No Abstract.Full Text
- A Navigation Aid for Blinds Using Stereo Vision and Vibrotactile Interface
Authors
1 PEC University of Technology, Chandigarh, IN
Source
Biometrics and Bioinformatics, Vol 4, No 9 (2012), Pagination: 435-439Abstract
The population of visually impaired people is increasing rapidly in India as well as in world. Many electronic travel aids for vision substitution in blinds were introduced in past twenty years. However, India is still lacking a realistic and low cost commercial solution that can provide portability and ease of use. This paper is aimed at discussing one such practical approach to building a real-time navigation aid for blinds while explaining our custom built research prototype. The vision substitution prototype discussed in this paper consists of a stereo vision based range finding system to detect obstacles, a bind computer interface built using vibrotactile interface for real time interactions with the user and a processing unit for meaningful transformation of obstacle distances into vibration alerts. This paper will discuss both hardware construction and software implementation along with various testing and experimentation scenarios that were carried out to validate the applicability of this prototype.
Keywords
Blind Navigation, Visually Impaired, Vibrotactile, Haptic, Stereo Vision, Blinds, Vision Substitution, Eta.
- Recognition of Traditional Medicine in the Nobel for Artemisinin is Inescapable
Authors
1 CSIR-Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Sukhdev Vihar, Mathura Road, New Delhi 110 025, IN
Source
Current Science, Vol 110, No 5 (2016), Pagination: 749-749Abstract
On whether or not the award of the Nobel Prize to Youyou Tu for the discovery of artemisinin is a vindication of the efficacy of traditional Chinese medicine, it is illuminating to compare certain facts and figures associated with her approach with that of modern antimalarial drug discovery. Tu had tested 200 recipes and 380 herbal extracts, selected on the basis of traditional Chinese medicine literature, in animal models, and identified extracts from Artemisia annua L., the source of artemisinin, with promising parasite growth-inhibiting activity.Full Text
- Joining of Nano-Composite using Friction Stir Welding
Authors
1 Indian Institute of Technology Hyderabad, ODF Campus, Yeddumaialram, AP, IN
Source
Manufacturing Technology Today, Vol 12, No 10 (2013), Pagination: 7-12Abstract
Currently, there is widespread use of thermoplastics, light-weight materials and fiber-reinforced plastics in aerospace, automobile, medical, electronic and construction industry. The product development with such materials requires them to be joined to have desired size and shape. Among the joining techniques the Friction Stir Welding (FSW) is a newer welding process that joins the materials in the solid state by heating them by frictional and deformation heat and subsequently stir them across the interface. Recently FSW has been studied for thermoplastics. The present paper reports joining of Alumina-Polypropylene nano-composite pieces using the FSW. The tool rotation speed and the traverse speed are allowed to vary and the joints are produced. It is observed that the nano-composite under the identical conditions is comparatively easy to join then the pure polymer. This paper represents one of the first ever attempts on joining of polymer nano-composites using FSW and calls for more investigations into FSW of variety of nano-composites.Keywords
Friction Stir Welding, Nano Composites, Injection Molding.- De-Noising of Image Using Adaptive Thresholding Technique
Authors
1 Sri Sainath University, LRIET, Solan, IN
Source
International Journal of Scientific Engineering and Technology, Vol 5, No 3 (2016), Pagination: 158-160Abstract
This paper describes a computationally more efficient and adaptive threshold e s t ima t i on method for image de-noising in the wavelet domain based on Generalized Gaussian Distribution (GGD) modelling of sub band coefficients. In this method, the choice of the threshold estimation is carried out by analyzing the statistical parameters of the wavelet sub band coefficients like standard deviation, arithmetic mean and geometrical mean. The noisy image is first decomposed into many levels to obtain different frequency bands. Then soft thresholding method is used to remove the noisy coefficients, by fixing the optimum thresholding value by the proposed method. Experimental results on several test images by using this method show that this method yields significantly superior image quality and better Peak Signal to Noise Ratio (PSNR). Here, in this paper, the role of wavelet based image de-noising by adaptive thresholding technique is discussed.Keywords
Image De-Noising, Wavelet Transform, Gaussian Noise, Filter Banks and Thresholding.Full Text
- Effect of Intermediate Sill on the Performance of Stilling Basin Model
Authors
1 Department of Civil Engineering, M.A.N.I.T., Bhopal, Madhya Pradesh, IN
Source
International Journal of Scientific Engineering and Technology, Vol 3, No 4 (2014), Pagination: 414-417Abstract
This research paper investigates about the performance of stilling basin models with different geometry of intermediate sill having height equivalent to the diameter of pipe outlet. The experimental study was carried out for three Froude numbers namely 3.85, 2.85 and 1.85 for non-circular pipe outlet. Performance index (PI) has been used to evaluate the performance of stilling basin models tested using same sand base material and test run time. The scour pattern was measured for each test run and flow pattern was also observed. After 15 tests runs, it was found that scour process were reduced for a specific geometry of intermediate sill having saquare shape of the height 1d at a particular location on stilling basin floor combined with end sill of particular size and shape. Performance of this model was found to be better than USBR VI impact basin for similar flow condition.Keywords
Intermediate Sill, Pipe Outlet, Stilling Basin, Scour Pattern.Full Text
- Design of Intze Tank in Perspective of Revision of IS:3370
Authors
1 Dept. of Civil Engg., MANIT, Bhopal, IN
Source
International Journal of Scientific Engineering and Technology, Vol 3, No 9 (2014), Pagination: 1193-1197Abstract
Intze type tank is commonly used overhead water tank in India. These tanks are designed as per IS:3370 i.e. Code of practice for concrete structures for storage of liquids. BIS implemented the revised version of IS 3370 (part 1& 2) after a long time from its 1965 version in year 2009. Presently large number of overhead water tanks is used to distribute the water for public utility. In which most of the water tanks were designed as per old IS Code:3370-1965 without considering earthquake forces. The objective of this dissertation is to shed light on the difference in the design parameters of (a) intze water tanks without considering earthquake forces (b) intze water tanks designed with earthquake forces. First design is based on Indian standard code:3370-1965 and second design is based on Indian standard code:3370-2009 and draft code 1893-Part 2, (2005) considering two mass modal i.e. impulsive and convective mode method. Intze tank supported on frame staging is considered in present study.Keywords
Intze Tank, Impulsive and Convective Mode, Sloshing Wave Height Etc.Full Text
- Enhancement in Mechanical Properties of Tailored Welded Blanks Due to Pulsed Tig Welding
Authors
1 Bharat Heavy Electrical Limited, Haridwar, IN
2 Institute of Petroleum Technology, Gandhinagar, IN
3 Department of Mechanical and Industrial Engineering, Indian Institute of technology Roorkee, Roorkee, 247 667, IN
Source
Indian Welding Journal, Vol 42, No 4 (2009), Pagination: 38-45Abstract
The present paper reports experimental results on enhancement in mechanical properties of tailored welded blanks due to Pulsed TIG welding. Experimental evaluation of various mechanical properties has been made under the influence of varying peak current, pulse frequency and pulse width. The resulting welds have been checked for ultimate tensile strength, % elongation, hardness, toughness and fatigue life. The mechanical properties of Pulsed TIG welded tailored blanks have further been compared with that produced by conventional TIG welding. It has been observed that the Pulsed TIG welding can successfully be employed to improve the mechanical properties of tailored welded blanks. The results of experiments have been analyzed and related discussion has been presented.
Keywords
Pulsed TIG Welding, Mechanical Properties, Tailored Welded Blanks.- Impact of Process Modelling on Current Direction of Welding Research and Future Targets
Authors
1 Institute of Petroleum Technology, Gandhinagar - 382 007, IN
2 Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
Source
Indian Welding Journal, Vol 41, No 4 (2008), Pagination: 43-50Abstract
The present paper gives a description of process modelling and its impact on current direction of welding research and future targets. It analyses the research work carried out in the filed of process modelling and presents quantitative analysis. The present work classifies and subsequently quantifies the welding research on the basis of approaches including modelling and simulation, product development, cause-effect analysis and sensor and control. The analysis indicates that modelling based research is primarily reported for existing technologies and existing materials. Research in new technologies using modelling is still is in developing stages and new materials based research is primarily carried out with cause-effect based analysis. The paper also mentions the future targets in welding research and indicates the role of process modelling in achieving the targets.
Keywords
Process Modelling, Welding Research, Future Targets.- A Comparative Study between Linear and Nonlinear Regression Analysis for Prediction of Weld Penetration Profile in AC Waveform Submerged Arc Welding of Heat Resistant Steel
Authors
1 Department of Mechanical & Aerospace Engineering, IIT Hyderabad, Sangareddy, IN
2 Technical Research Institute, Hitachi Zosen Corporation, Osaka, JP
3 Joining & Welding Research Institute, Osaka University, JP
Source
Indian Welding Journal, Vol 52, No 1 (2019), Pagination: 40-48Abstract
Alternating current with square waveform provides better control of weld quality and reduces the effect of the arc-blow in the submerged arc welding process. This paper presents a comparative study in between conventionally used linear regression and newly proposed nonlinear regression analysis for prediction of weld penetration profile, i.e. weld width, penetration and penetration shape factor in the AC waveform welding of heat resistant steel. The comparison is based on second order linear regression and nonlinear regression analysis using Levenberg-Marquardt method. The frequency, electrode negative ratio, welding current, and welding speed are used as input parameters to obtain the models for penetration and width. The models are developed following a design of experiment and extra experiments are conducted to check the adequacy of the models. The results show that the Levenberg-Marquardt method associated with exponential function without considering constant term is more effective as compared to second order linear regression in terms of predictability and accuracy. The significant effect of process variables on the outcomes is analyzed. The investigation shows a new approach to weld penetration profile prediction that can be horizontally deployed to other welding process where predication is difficult because of the complex shape of the weld bead.
Keywords
Weld Bead Geometry, Linear Regression, Process Variable, Nonlinear Regression, Model Adequacy.References
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- Arc Behavior Study Using Welding Current Module and its Impact on Residual Stress and Weld Bead in Anti-Phase Synchronized Twin-Wire Gas Metal Arc Welding
Authors
1 Department of Mechanical & Aerospace Engineering, Indian Institute of Technology, Hyderabad- 502285, IN
Source
Indian Welding Journal, Vol 52, No 1 (2019), Pagination: 64-70Abstract
The importance of twin-wire welding in increasing the deposition rate is known for a long, but its application in gas metal arc welding is limited due to the arc-stability related issues. An unstable welding arc causes irregular weld bead and material loss in the form of spatters. Previous investigations indicate that the problem can be addressed through arc-stability induced by dissimilar twin-arcs as the electromagnetic field concentrates around the arc with higher current. The present study is intended to reduce the twin-arcs' interactions and to improve the arc stability in twin-wire gas metal arc welding by evaluating different conditions at lead and trail wires. Further, their influence on the residual stresses and weld bead geometry is studied. Bead-on-plate-welds are carried out. A data acquisition system is used to capture the electrical signals during welding. The results indicate that the unequal currents at trail and lead wires provide stability to the arc that also results in a shift in residual stresses from compressive to tensile along the weld transverse direction. In addition, the maximum residual stress is located at the weld toe. When the current difference between the trail and lead wire is more, the arc produces stable metal transfer with uniform heating and cooling that results in reduction in stresses and improvement in weld quality.
Keywords
Twin-Wire GMAW, Heat Input, Residual Stresses, Weld Bead Geometry.References
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- Modified Mathematical Models for Melting Rate in Submerged Arc Welding
Authors
1 Institute of Petroleum Technology, Gandhinagar, IN
2 Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee, IN
3 Department of Mechanical and Industrial Engineering, IN
Source
Indian Welding Journal, Vol 40, No 4 (2007), Pagination: 21-32Abstract
Modified mathematical models for melting rate during submerged arc welding with straight and reverse polarities have been proposed. The present work is a result of a critical analysis of existing models and subsequent modification in order to improve the predictability and practicability. The proposed models bridge the gap between less scientific shop-fioor-friendly models and scientifically correct but not so shop-floor- friendly models. Instead of experimental measurement of electrode extension or making the assumption that the electrode extension is equal to contact tube to work-piece distance, the present work models the role of electrode extension during melting by considering the effect of process parameters on it. On the other hand, influence of process parameters on arc heating has also been incorporated. The developed models cover the effect of fundamental parameters like current, voltage, electrode extension and wire diameters.
Simulated annealing has been used to calibrate the proposed models and subsequently the models are validated with data points different from the points used for model calibration. The modified models provide better accuracy than the models that have been constituted with the above stated assumption as well as it is more practical than those models in which actual electrode extension has been experimentally measured. The outcome of investigation has been analyzed in terms of improvement in the predictability, resemblance with physics of the process and generalization capacity of the models. The approach of the present work is applicable for future research in other welding processes.