2013
3
1
1
0
Effect of welding parameters on pitting corrosion rate of pulsed current micro plasma arc welded AISI 304L sheets in 1N HCl
2
2
Austenitic stainless steel sheets have gained wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance such as metal bellows used in expansion joints in aircraft, aerospace and petroleum industries. In the case of single pass welding of thinner sections of this alloy, Pulsed Current Micro Plasma Arc Welding (PCMPAW) has been found beneficial due to its advantages over the conventional continuous current process. This paper highlighted development of empirical mathematical equations using multiple regression analysis, correlating various process parameters to pitting corrosion rates in PCMPAW of AISI 304L sheets in 1 Normal HCl. The experiments were conducted based on a five factor, five level central composite rotatable design matrix. The model adequacy was checked by Analysis of Variance (ANOVA). The main effects and interaction effects of the welding process parameters on pitting corrosion rates of the welded joints were studied using surface and contour plots. From the contour plots, it was understood that peak current was the most influencing factor on the pitting corrosion rate. The optimum pitting corrosion rate was achieved at peak current of 6 Amperes, base current of 4 Amperes, pulse rate of 40 pulses/second and pulse width of 50 % .
1

1
11


Kondapalli
Siva Prasad
Assistant Professor, Department of Mechanical Engineering, Anil Neerukonda Institute of Technology & Sciences , Visakhapatnam, India
Assistant Professor, Department of Mechanical
Iran


Chalamalasetti
Srinivasa Rao
Associate Professor, Department of Mechanical Engineering, AU College of Engineering, Andhra University, Visakhapatnam, India
Associate Professor, Department of Mechanical
Iran


Damera
Nageswara Rao
Vice Chancellor, Centurion University of Technology & Management, Odisha, India
Vice Chancellor, Centurion University of
Iran
AISI 304L
Pulsed current
Micro plasma arc welding
Pitting corrosion
Study on buckling of steel cylindrical shells with an elliptical cutout under combined loading
2
2
In this paper, simulation and analysis of thin steel cylindrical shells with elliptical cutouts under oblique loading were studied using finite element method. First, the numerical results were validated by the results of experimental test performed by an INSTRON 8802 servo hydraulic machine. Also, the effect of cutout angle (θ), cutout size, cutout position (L0/L) and cutout aspect ratios (b/a) were investigated, where parameter (a) shows size of the cutout along longitudinal axis of the cylinder, parameter (b) is size of the cutout in circumferential direction of the cylinder on the buckling and postbuckling behavior of cylindrical shells with finite element method. It can be concluded that increasing width of the cutout extremely decreased the buckling load while the cutout height was constant. Moreover, changing position of the cutout from the midheight of the shell toward the edges increased the buckling load.
1

13
25


Abdolhossein
Fereidoon
Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
Faculty of Mechanical Engineering, Semnan
Iran


Kamal
Kolasangiani
Department of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran
Department of Mechanical Engineering, Shahrood
Iran


Amin
Akbarpour
Department of Mechanical Engineering, Semnan Branch, Islamic Azad University, Semnan, Iran
Department of Mechanical Engineering, Semnan
Iran


Mahmoud
Shariati
Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
Department of Mechanical Engineering, Ferdowsi
Iran
Buckling
cutout
combined loading
Multiobjective optimization and analysis of electrical discharge machining process during microhole machining of D3 die steel employing salt mixed deionized water dielectric
2
2
Correct selection of manufacturing condition is one of the most important aspects which should be considered in the majority of manufacturing processes, particularly in the process related to advanced machining process like electrical discharge machining. In electrical discharge machining (EDM), dielectric fluid plays an important role since machining characteristics are greatly influenced by the nature or characteristics of employed dielectric. Moreover, adding various types of abrasives or salt in the fluid at different concentrations also affect the machining performance because of changing dielectric strength property. The present paper addressed the influence of NaNO3 mixed deionized water as a dielectric fluid on microhole machining performance criteria such as material removal rate (MRR), tool wear rate (TWR), overcut (OC) and taper during machining of D3 die steel plate.
1

27
39


I.
Shivakoti
Mechanical Engineering Department, Sikkim Manipal Institute of Technology (SMIT), Mazitar,Sikkim737136, India
Mechanical Engineering Department, Sikkim
Iran


G.
Kibria
Mechanical Engineering Department, Aliah University Kolkata700091, India
Mechanical Engineering Department, Aliah
Iran


S.
Diyaley
Mechanical Engineering Department, Sikkim Manipal Institute of Technology (SMIT), Mazitar,Sikkim737136, India
Mechanical Engineering Department, Sikkim
Iran


B. B.
Pradhan
Mechanical Engineering Department, Sikkim Manipal Institute of Technology (SMIT), Mazitar,Sikkim737136, India
Mechanical Engineering Department, Sikkim
Iran
Electric discharge machining
Deionized water
D3 die steel
Dielectric fluid
Taguchi method
Investigation of electrokinetic mixing in 3D nonhomogenous microchannels
2
2
A numerical study of 3D electrokinetic flows through micromixers was performed. The micromixers considered here consisted of heterogeneous rectangular microchannels with prescribed patterns of zetapotential at their walls. Numerical simulation of electroosmotic flows within heterogeneous channels requires solution of the NavierStokes, ErnestPlank and species concentration equations. It is known that a 3D solution of these equations is computationally very intensive. Therefore, the wellknown HelmholtzSmoluchowski model is often used in numerical simulation of electroosmotic flows. According to 2D studies on electrokinetic mixing inside heterogeneous channels, existence of vortices within the flow field always increases mixing performance. Hence, it may be expected that similar observations pertain to mixing in 3D flows as well. However, investigations on 3D micromixers identified situations in which existence of vortices had little or no significant benefit to the mixing performance. Findings of the present work indicated degree of flow asymmetry as a key parameter for the mixing performance. Since 3D flows are more capable of developing asymmetrical flow patterns, they are expected to have better mixing performance than their 2D counterparts. The results presented here for different 3D cases showed that mixing performance could be improved significantly depending on the alignment of vortex plane relative to the mixing interface of the fluids. These observations confirmed that 2D simulations of mixing could not fully explain behavior of passive micromixers.
1

41
52


J.
Jamaati
Razi University, Department of Mechanical Engineering, Kermanshah, Iran
Razi University, Department of Mechanical
Iran


H.
Niazmand
Ferdowsi University of Mashhad, Department of Mechanical Engineering, Mashhad, Iran
Ferdowsi University of Mashhad, Department
Iran


M.
Renksizbulut
University of Waterloo, Department of Mechanical & Mechatronics Engineering, Waterloo, Canada
University of Waterloo, Department of Mechanical
Iran
Mixing
Electroosmotic
HelmholtzSmoluchowski model
Nonhomogeneous
Chemical reaction and radiation effects on MHD free convection flow through a porous medium bounded by a vertical surface with constant heat and mass flux
2
2
In the present paper, an analysis was carried out to investigate effects of radiation on a free convection flow bounded by a vertical surface embedded in a porous medium with constant suction velocity. It was under the influence of uniform magnetic field in the presence of a homogenous chemical reaction and viscous dissipation with constant heat and mass flux. The nondimensional governing equations were solved analytically and the expressions were found for velocity, temperature and concentration fields. Also, the expression for skin friction near the plate was derived and the results were discussed in a table.
1

53
62


T.
Sudhakar Reddy
Department of Mathematics, Priya Darshini Institute of Technology, Tirupati, Andhra Pradesh, India517507
Department of Mathematics, Priya Darshini
Iran


M. C.
Raju
Department of Mathematics, Annamacharya Institute of Technology and Sciences Rajampet (Autonomous), Rajampet, Kadapa District, Andhra Pradesh, India 516126
Department of Mathematics, Annamacharya Institute
Iran


S. V. K.
Varm
Department of Mathematics, Sri Venkateswara University, Tirupati, Andhra Pradesh, India – 517502
Department of Mathematics, Sri Venkateswara
Iran
MHD
Free convection
Vertical surface
Constant heat and mass flux
Free convection in a 3D chamber with local cooling and heating
2
2
This paper modeled heating air of a room through examining free convection in a 3D chamber. The chamber had cold and hot sources with Tc and Th temperatures, respectively. Its other walls were adiabatic. This study aimed at predicting effect of temperature difference, displacement of hot and cold sources and their aspect ratio on flow field, temperature and heat transfer rate. To conduct the study, mass conservation, momentum and energy equations were applied in laminar and 3D states while assuming fluid constant properties, except density, in the power of buoyancy (Boussinesq approximation). Final difference method (FDM) was used for numerical solution of the governing equations based on the volume control and SIMPLE algorithm. According to the modeling results, the most favorable temperature distribution in the chamber (room) was obtained when the heat source (radiator) was located on the wall under the cold source (window). Reducing the distance between the two sources would result in increasing heat transfer from the heating sources.
1

63
74


M.
Nasiri
Shahrekord University, Department of Mechanical Engineering, Shahrekord, Iran
Shahrekord University, Department of Mechanical
Iran


B.
Ghasemi
Shahrekord University, Department of Mechanical Engineering, Shahrekord, Iran
Shahrekord University, Department of Mechanical
Iran
Free convection
3D chamber
Nusselt number
Rayleigh number
Derivation of turbulent energy in a rotating system
2
2
Energy equation for turbulent flow in a rotating system was derived in terms of second order correlation tensors, where the correlation tensors were functions of space coordinates, distance between two points and time. To reveal the relationship of turbulent energy between two points, one point was taken as origin of the coordinate system. Due to rotation, the Coriolis force played an important role in the rotating system of turbulent flow. The correlation between pressure fluctuations and velocity fluctuations at the two points of flow field was applied to the turbulent energy equation, in which the Coriolis force and centrifugal force acted on the fluid.
1

75
83


S. F.
Ahmed
Prime University, Mirpur1, Dhaka1216, Bangladesh
Prime University, Mirpur1, Dhaka1216, Bangladesh
Iran
Energy equation
Turbulent flow
Rotating system
Twopoint correlation
Correlation tensor