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An Experimental Study of Settling Velocity in Turbulence
Using the Digital Particle Image Velocimetry Technique
--Manoj Kumar, Jyoti Raman and Priya
In this paper, turbulence influence on the settling behavior of fine sand particles was investigated by conducting experiments in a water tank with turbulence generated by a grid oscillating in the vertical direction. Digital Particle Image Velocimetry (DPIV) system with enhanced shadow processing function was employed to conduct simultaneous velocity measurements of individual fine sand particles driven by gravity and the ambient fluid in the confined turbulent environment. The spherical shape and diameter (3.0-6.0 mm) of fine sand particles were tested with different oscillating frequencies. The turbulence effects on the relative settling velocity were expressed in terms of different dimensionless parameters, such as Stokes number, Richardson number and dimensionless turbulence length scale. The two main findings were observed from the experimental investigation: (i) the turbulence decays followed the power law; and (ii) the integral length scale increases linearly with the distance from the grid. The flow formation near the grid was also experimented in detail with the advantage of the planar measurements. The results showed that shear flow perceptibly exists near the vertically oscillating grid and homogeneity of the turbulence can only be achieved at a distance from the vertically oscillating grid greater than about three mesh sizes. © 2015 IUP. All Rights Reserved.
An Analysis of Surface Integrity of Machined Inconel-718
--Panditrao S M, Patil T S, Soman A A, Achara U J and Shinde S N
This study aims at investigating the effect of cutting speed, feed rate and depth of cut on surface roughness, microstructure of machined part and tool wear in dry rough turning of Ni superalloy Inconel-718 using PVD coated (TiAlN + TiN) carbide tool inserts. Taguchi’s method for optimization of machining parameters (vc = 40-60 m/min, f = 0.05-0.1 mm/rev and d = 0.25-0.5 mm) was used. A Finite Element (FE) model of the tool geometry was developed in order to understand the trends of deformation and shear stress induced due to mechanical loads during orthogonal machining. Regression equations versus the cutting parameters were obtained for surface finish and tool wear. Changes in microstructure were found to be negligible. The investigation suggested that for PVD coated (TiAlN + TiN) carbide tool inserts, cutting speed of 60 m/min, feed rate of 0.05 mm/rev and depth of cut of 0.5 mm were optimum for producing the best cutting results. © 2015 IUP. All Rights Reserved.
Development of Computerized Maintenance Management
Information System for Rico Industries, Gurgaon
--Himanshu Arha, Paramjeet Yadav, Anshul Singhwal, Nishtha Saini and P C Tewari
The expansion of industries both in terms of volume and variety creates the need to understand the importance of maintenance besides production. It is always difficult to manage a large and cumbersome amount of maintenance and technical data in any industry. To deal with it, a computer-aided tool is required to make the system reliable, precise and fast. The paper deals with the development of Computerized Maintenance Management Information System (CMMIS) for Rico Industries, Gurgaon. The system is designed and developed by C# (C Sharp) as front end and SQL Server as back end. The system includes modules and their reports such as equipment details, tools and spares, preventive maintenance schedules, maintenance staff and safety records, condition monitoring techniques and calibration, Root Cause Analysis (RCA) and feedback. © 2015 IUP. All Rights Reserved.
The Effect of Milling Time on Density and Microstructural
Characterization of Si3N4/Gr Ceramic Powder
--Pardeep Sharma, Dinesh Khanduja and Satpal Sharma
Silicon nitride and graphite ceramic powders with a supposed composition of 50% of each by weight were mechanically alloyed in laboratory ball mill with different milling times (12.5, 25, 50, 75 and 100 hours). The investigation was carried out on the microstructure and density of ball-milled powder. It was observed that with milling time density increased initially and then started decreasing. The density was 2.83 at 0 hours and 2.81 g/cm3 at 100 hours. The results showed that ball milling is a very dominant method and a very dynamic process for preparation of combined powder with homogeneous microstructure having appropriate morphology and homogenized density. © 2015 IUP. All Rights Reserved.
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