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.

Abstract: We are inspired by the steering mechanism of TANKS used by army "Differential Drive " Here we have tried to deploy this mechanism in BACKHOE LOADER. It is a prototype just to explain differential drive mechanism, to make it more useful and safe while operating. It comes under the branch ERGONOMICS- which is the study of human machine relationship.

Keywords: Mechanical, Megatronics, Ergonomics, Vehicle, Saftey

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Abstract: This work proposes an effective numerical model based on the Computational Fluid Dynamics (CFD) approach to obtain the flow structure around a passenger car with Tail Plates. The experimental work of the test vehicle and grid system is constructed by ANSYS-14.0. FLUENT which is the CFD solver & employed in the present work. In this study, numerical iterations are completed, then after aerodynamic data and detailed complicated flow structure are visualized. In the present work, model of generic passenger car has been developed in solid works-10 and generated the wind tunnel and applied the boundary conditions in ANSYS workbench 14.0 platform then after testing and simulation has been performed for the evaluation of drag coefficient for passenger car. In another case, the aerodynamics of the most suitable design of tail plate is introduced and analysedfor the evaluation of drag coefficient for passenger car. The addition of tail plates results in a reduction of the drag-coefficient 3.87% and lift coefficient 16.62% in head-on wind. Rounding the edges partially reduces drag in head-on wind but does not bring about the significant improvements in the aerodynamic efficiency of the passenger car with tail plates, it can be obtained. Hence, the drag force can be reduced by using add on devices on vehicle and fuel economy, stability of a passenger car can be improved.

Keywords: Aerodynamic Drag, Coefficient of Drag, Coefficient of Lift,Tail Plate, Wind tunnel simulation, ANSYS FLUENT, Generic passenger car, CFD.

[1] Gilhaus, R. Hoffmann, Directional Stability, Aerodynamics of Road Vehicles, in: W.H. Hucho (Ed.), SAE International, Warrendale, PA, 1998.

[2] J.R. Callister, A.R. George, Wind Noise, Aerodynamics of Road Vehicles, in: W.H. Hucho (Ed.), SAE International, Warrendale, PA, 1998.

[3] F.R. Bailey, H.D. Simon, Future Directions in Computing and CFD, AIAA Paper 92-2734, 1992.

[4] H. Taeyoung, V. Sumantran, C. Harris, T. Kuzmanov, M. Huebler, T. Zak, Flow-field simulations of three simplified vehicle shapes and comparisons with experimental measurements, SAE Transactions 106 (1996) 820–835.

[5] Fluent 6.1 User's Guide, Fluent Inc., Lebanon, NH, 2003.

[6] TGrid 3.4 User's Guide, Fluent Inc., Lebanon, NH, 2001.

[7] B. Lokhande, S. Sovani, J. Xu, Computational Aero-acoustic Analysis of a Generic Side View Mirror, SAE 2003-01-1698, 2003.

[8] Ahmad, K., Khare, M., Chaudhry, K.K., 2002. Model vehicle movement system in wind tunnels for exhaust dispersion studies under various urban street configurations. Journal of Wind Engineering and Industrial Aerodynamics 90, 1051 e 1064

[9] Abdul Ghani, S.A.A., Aroussi, A., Rice, E., 2001.Simulation of road vehicle natural environment in a climatic wind tunnel. Simulation Practice and Theory 8, 359–375.

[10] Muyl, F., Dumas, L., Herbert, V., 2004. Hybrid method for aerodynamic shape optimization in automotive industry. Computers and Fluids 33, 849–858.

Abstract: UAV (Unmanned Aerial Vehicle) is an air vehicle which is largely used for surveillance, monitoring, reconnaissance, data relay, and data collection or to enter the area which is not safe for human i.e. flood affected or virus affected area. This paper represents the unique design of such an UAV which designed at MILITARY INSTITUTE OF SCIENCE & TECHNOLOGY to participate in an international competition SAE Aero Design West-2013. As per competition requirement empty weight of the UAV must be less than 2 lb and must fly with payload as heavy as possible for good scoring. Initially, the model of the UAV was tested in wind tunnel and the test data showed that the model aircraft performance was capable enough for flying and covering an area specified in the competition. Subsequently, an actual aircraft was fabricated of that model and flight tested which proved the match with theoretical, statistical and experimental data that was obtained from wind tunnel test, wing tip test, tensile test of manufacturing material and CFD (Computational Fluid Dynamics) flow simulation over the aerofoil.

Keywords: Unmanned aerial vehicle (UAV), NACA 4412, unique design UAV.

[1] John D Anderson Jr., Introduction to flight (7 West Patel Nagar, New Delhi, Tata McGraw-Hill Publishing Company Limited, Fifth edition).
[2] L J Clancy. Aerodynamics (Melborne, Pitman Publishing Limited)
[3] Kermode, Mechanics of flight (Hong Kong, Pearson Education Limited, 2006)
[4] John D. Anderson, Jr. Fundamentals of aerodynamics (1221 Avenue of the Americas, New York, McGraw-Hill, 3rd edition)
[5] John D. Anderson, Jr. Aircraft performance and design (7 West Patel Nagar, New Delhi, Tata McGraw-Hill Education Private Limited, Fifth edition)
[6] Daniel P Raymer. Aircraft Design: a conceptual approach (Washington D.C., American Institute of Aeronautics and Astronautics, Inc.)
[7] Jonathan How, Ellis King and Yoshiaki Kuwata, Flight Demonstrations of Cooperative Control for UAV Teams, AIAA 3rd "Unmanned Unlimited" Technical Conference, Workshop and Exhibit . Chicago, Illinois, September 2004.
[8] HaiYang Chao, YongCan Cao and YangQuan Chen, Autopilots for Small Unmanned Aerial Vehicles: A Survey, International Journal of Control, Automation, and Systems, 8(1), 2010, 36-44.
[9] Selcuk Bayraktar, Georgios E. Fainekos and George J. Pappas, Experimental Cooperative Control of Fixed-Wing Unmanned Aerial Vehicles, 43rd IEEE Conference on Decision and Control, Atlantis, Paradise Island, Bahamas, December, 2004.
[10] Lee Nicholai's White Paper (students.sae.org/competitions/aerodesign/rules/aero_nicolai.doc)

Abstract:This paper presents two models for predicting the delay percentage in construction projects in Egypt. The first model based on regression analysis. 74 causes that lead to delay in construction projects gathered from literature. A questionnaire survey was made on construction contractors of construction projects in Egypt to evaluate the relative importance of these causes. 14 causes were obtained as the most significant causes that affect the delay percentage (DP) and these are the independent variables of the proposed model. Data for the occurrence of the previous causes on a yes/no basis and the corresponding DP (dependent variable) for 20 construction projects was collected. The data was divided into two sets, the first set contains projects for the purpose of model building. The results revealed that there was a strong linear relationship between DP and 9 causes from 14 causes that significantly affect DP of projects. These causes are: difficulties in obtaining work permits from authorities concerned, original contract duration too short, inflation, difficulties in financing the project by the contractor, effect of subsurface conditions, changes in the scope of the project, economic conditions, excessive bureaucracy in the owner administration, and inefficient coordination by the owner in the early planning &design stages. The second set contains 8 projects for the validation purposes and comparison with the second model. The second model is a statistical fuzzy approach which is a hybrid approach from fuzzy logic and regression analysis. A regression equation between each cause and DP using projects of first set was extracted. The relative weight of each cause is determined by its coefficient of determination (R2 ) value. The degree of severity each cause had received from questionnaire analysis was used to fuzzify this cause. A trapezoidal membership function was used to represent the delay percentages in construction projects in general depending on 18 out of 30 the previous 20 projects. Two projects were excluded from this function due to their divergence values from other projects. Thus, the expected delay percentage of a project is then determined using fuzzy rules. Validation of the two models using projects of the second set revealed that regression model has prediction capabilities higher than that of statistical fuzzy model. The average percentage error for regression model was 30.3, against 38.5 for statistical fuzzy model.

Keywords: Regression Analysis; Questionnaire Survey; Statistical Fuzzy Model

[1]. Abd El-Razek, M. E., Bassioni, H. A., and Mobarak, A. M. "Causes of Delay in Building Construction Projects in Egypt" J. of Construction Eng. Manage., Vol.134, No.11, Nov. 1 ,2008.
[2]. Abdalla, M.O. and Battaineh "Causes of Construction delay: Traditional Contracts." Int. J. of Project Manage., 20: 67-73, 2002.
[3]. Abedi, M., Mohamad, M. F., and Fathi, M. S.," Effects of Construction Delays on Construction Project Objectives." P. of the first Iranian Students Scientific Conference in Malaysia, April, 2011.
[4]. Ahmed, S.M., Azhar, S., Castillo, M., and Kappagntula, P., "Construction Delays in Florida: An Empirical Study." Florida International University, Miami, March, 2010.
[5]. Al- Ghafly, M.A., "Delay in the Construction of Public Utility Projects in Saudi Arabia." M.Sc thesis, faculty of the Collage of graduate Studies, King Fahd Univ. of Petroleum & Minerals, Dhahran, Saudi Arabia, 1995.
[6]. Al- khalil, M.I., and Al- Ghafly, "Delay in Public Utility Projects in Saudi Arabia" Int. J. of Project Manage., 17: 101-106, 1999.
[7]. Al Sultan, A.S., "Determination of Construction Contract Duration for Public Projects in Saudi Arabia." M.Sc thesis, King Fahd Univ. of Petroleum& Minerals, Dhahran, Saudi Arabia, 1989.
[8]. Alaghbari, W. A. M., "Factors Affecting Construction Speed of Industrialized building Systems inMalaysia, M.sc. Thesis, University Putra Malaysia, Serdang, 2005.
[9]. Al-Moumani, H.A., "Construction Delay: A quantitative Analysis." Int. J of Project Manage., 18: 51-59.