iosr-JMCE   Volume-7 ~ Issue-5

Abstract: Aluminum alloys are used in many applications in which the combination of high strength and low weight is attractive; ship building, air frame, transportation industry etc. are some areas in which the low weight can be significant value. Friction stir welding (FSW) is a new welding technique particularly well suited to aluminum alloys though this technique is also used for other materials. Friction stir welding promises joints with low porosity, fine microstructures, minimum phase transformation and low oxidation compared to conventional welding techniques. It is capable of joining combinations of alloys not amenable to conventional welding.Experiments for tensile and deflection tests were carried out and reported in this research paper. The base material used for friction stir welding was AA 6351–T4 Aluminum alloy. Tensile strength and breaking loads were increased with increase of rotational speed of the tool but it drops after attaining marginal speed. Deflections of friction stir welded specimens and base materials were compared and they exhibited almost similar trends at different load conditions and deflections of all the specimens were increased with increment of load.

Keywords - Friction Stir Welding (FSW), Aluminum AA 6351 alloy, tensile strength, breaking load and deflection.

[1] Thomas WM, Nicholas ED, Needham JC, Murch MG, Templesmith P, Dawes CJ, WO/1993/010935, International Patent Number PCT PCT/GB92/02203, TWI, Improvements relating to friction welding; 1992.

[2] Nandan R, DebRoy T and Bhadshia HKDH, Recent advances in friction stir welding – process, weldment structure and properties, Progress in Material Science 53 (2008) 980-1023.

[3] Mishra RM, Mahoney MW, Friction stir welding and processing, ASM Int; 2007

[4] Terry Khaleed, An outsider looks at friction stir welding, ANM–112N-05-06 (July 2005).

[5] Williams SW, Air Space Eur 2001; 3 (3-4):64.

[6] Dawes J, An introduction to friction stir welding and its development, Welding & Me & l Fab, January, 1995, P-12.

[7] Liu G, L.E.Murr, Niou CS, McClure JC and Vega FR, Microstructural aspects of the friction stir welding of 6061 – T6 Aluminum, Scripta Materialia, Volume 37, Issue 3, 1 August 1997, Pages 355-361.

[8] L.Ceschini, I Boromei, G.Minak, A.Morri, F.Tarterini, Microstructure, tensile and fatigue properties of AA6061/20 Vol% Al2O3P friction stir welded joints, Journal of Composites, Applied Science and Engineering, Apr 2006, pp 1200 – 1210.

[9] A.KShukla, W.A.Baeslack III, Study of Microstuctural Evolution in Friction-Stir welded thin sheet Al-Cu-Li alloy using transmission –electron microscopy, Journal of Science Direct, Jan 2007, pp 513 – 516.

Abstract: Musculoskeletal disorders (MSDs) are amongst the most common work-related problems throughout the world and India is no exception. MSD risk factors can be an appropriate base for planning and implementing ergonomics intervention programs in the workplace. The present study is focused on identifying the occupational health and safety risks of workers in Indian sawmills. The workers in saw mills are exposed to MSD risks, hard environmental conditions (high temperatures, slippery and uneven ground), heavy works (manual handling of loads, awkward postures, ) and dangerous tools and machineries such as chainsaws, band saw, chippers, etc. . In this study we have considered different logger groups working in saw mills in Karnataka State and analyzed their MSD risk exposure, occupational health hazards and noise exposure. In a developing country like India, where labor is cheap and most of the workers are economic migrants, proper occupational health, hygiene and ergonomic factors are neglected . The workers accept the adverse working conditions as part of the job and mostly work in such work environments. NORDIC musculoskeletal questionnaire was used to analyze areas of pain and their occurrence in the past. Postural analysis using REBA, RULA indicates that the workers are working above the safe limit. The average REBA score observed was 7.5. The hazardous postures and MSD's were also justified by the questionnaires and VAS (Visual Analogue Scale) techniques. Moreover the workers were exposed to noise levels above the OSHA's safe limits for prolonged time. These methods indicated that different body parts at specific postures are vulnerable to injury and musculoskeletal disorders and warrant immediate ergonomics intervention

Keywords -Ergonomics, Musculoskeletal disorders, saw mill, RULA, REBA, Noise

[1] Andersson ER, Economic evaluation of ergonomic solutions: part I—guidelines for the practitioner, International Journal of Industrial Ergonomics. 1992, (10),161–71.

[2] Nunes, I. L., FAST ERGO_X – a tool for ergonomic auditing and work-related musculoskeletal disorders prevention, WORK: A Journal of Prevention, Assessment, & Rehabilitation, Vol. 34(2) ,2009, 133-148

[3] Judd H. Michael and Janice K. Wiedenbeck, Safety in the wood products industry. Forest Products Journal, Vol. 54, No. 10, 2004

[4] Segun R. Bello and Yahaya Mijinyawa., Assessment of Injuries in Small Scale Sawmill Industry of South Western Nigeria‖. Agricultural Engineering International: the CIGR Journal of Scientific Research and Development. Manuscript 1558. Vol. XII, March, 2010.

[5] Troy Jones Shrawan Kumar-, Comparison of Ergonomic Risk Assessment Output in Four Sawmill Jobs, International Journal of Occupational Safety and Ergonomics (JOSE) 2010, Vol. 16, No. 1, 105–111

[6] Thomee R, Grimby G, Wright BD, Linacre JM, Rasch analysis of Visual Analog Scale measurements before and after treatment of patellofemoral pain syndrome in women, Scand J Rehabil Med 1995, 27, 145-51.

[7] Sue Hignett,Lynn McAtamney - Rapid Entire Body Assessment (REBA), Applied Ergonomics 31 (2000) 201- 205

[8] McAtamney, L. and Corlett, E. N., RULA: a survey method for the investigation of work related upper limb disorders. Applied Ergonomics, 24, 1993, 91-99.

[9] Qutubuddin S.M., Hebbal S.S. and A.C.S. Kumar, A Review on Effect of Industrial Noise on the Performance of Worker and Productivity, International Review of Applied Engineering Research. Volume 2, Number 1 (2012), pp. 43-54

Abstract:Now a day, horizontal axis wind turbines play key role, in the field of power generation. But, the cost of power generation becomes high, when compared with power generation by other methods. In the present work the emphasis is focused on increasing the conversion efficiency of a wind turbine. The combination of convergent nozzle and diffuser has been fabricated as a part of the work and carried out experiments in the following manner.
 By placing a convergent nozzle at the inlet of wind turbine.
 By placing diffuser at the outlet of wind turbine.
 By using the combination of convergent nozzle and divergent nozzle
The power coefficient of the turbine is determined at various angle of attack in the range of 00 to 900.

Keywords: Power Coefficient, Betz limit Subject Classification: Wind Energy Conversion

[1]. Oman, R.A., Foreman, K.M., Gilbert, B.L. 1975, "A Progress Report on the Diffuser Augmented Wind Turbine" Workshop on Wind Energy Conversion Systems Washington DC, USA p. 829-826

[2]. G.D. Rai, Non-conventional Energy Sources, Dhanpat Rai and Sons, New Delhi, 1998.

[3]. Phillips, DG; Flay, RGJ and Nash, TA. Aerodynamic Analysis and Monitoring of the Vortex 7 Diffuser-augmented Wind Turbine.

[4]. D. Mukherjee- 2007 - Renewable energy sources 271-285, 20(2001).

[5]. Mechanical Engineering - Free E-Books - E-Books Directory www.e-booksdirectory.com › Engineering

[6]. K.M. Mital, Non-conventional Energy Sources
[7]. India Wind energy Associations http://www.inwea.org/
[8]. Web site of American wind energy association (http://www.awea.org)
[9]. www.ascent- journals.com
[10]. www.project paradise.com

Abstract:Cooling towers are the biggest heat and mass transfer devices that are in widespread use. In this paper we use a natural draft counter flow cooling tower in investigating the performance of cooling tower in different seasons. The humidity is defined as water particles present in air. The humidity is the major factor in the atmosphere, it depends upon ambient temperature. Humidity is high in winter season and low in summer season. The performance of the natural draft cooling tower is dominated by wind speed, ambient air temperatures and humidity in the atmospheric conditions. When the humidity is high in atmosphere, large quantity of water is required for cooling condensate. When humidity is low in atmosphere, small quantity of water is required for cooling condensate. The value of relative humidity in the atmosphere varies from place to place and season. The different losses in the cooling tower such as drift losses, evaporation losses and blow down losses can be calculated. The maintenance of cooling tower in the form of removal of scale or corrosion plays important role in the performance of the tower. The performance of the natural draft cooling tower of 500 MW is evaluated.

Keywords: Cooling tower, cycle of concentration, DBT, HVAC, losses, Relative humidity, WBT

[1]. P.K. Nag Engineering Thermodynamics; Tata McGraw Hill publications
[2]. Arora and Domakundwar, power plant engineering, dhanpat rai & co.,
[3]. Z. Zhai, S. FU, Improving cooling efficiency of dry cooling towers under cross wind conditions by using wind break methods, Applied Thermal Engineering 26(2004) 914-923
[4]. A.K.M. Mohiuddin, K. Kant, knowledge base for the systematic design of wet cooling tower.
[5]. J. Smrekar, I .Kustrin, J. Oman, methodology for evaluation of cooling tower performance –part 1:description of the methodology, Energy Conversion and management 52 (2011) 3257-3264.
[6]. B.T. Nijaguna, Thermal Science data book.
[7]. Fisenko, S.P.,Petruchik, A.I. and Solodukhin, A.D .Evaporative cooling of water in a natural draft cooling tower. International Journal of Heat and Mass Transfer, 45:4683-4683-4694, 2002
[8]. Mohiuddin AKM, Kant K. Knowledge base for the base for the systematic design of wet cooling towers. Part ІІ: fill and other design parameters. Int J Refrig 1996;19(1):52-60.