Experimental Investigations on The Effect of Tungsten Content on the Machining Behaviour of Tungsten Heavy Alloys

The present work attempts to assess the machinability of tungsten heavy alloys (WHAs) with varying tungsten content in terms of different machining characteristics such as chip thickness, material removal rate, cutting force and surface roughness under varied cutting conditions. The feed rate is found to have major influence on the machining characteristics; whereas the effect of rake angle appears to be marginal. With increase in W content both cutting force and material removal rate increase whereas surface roughness decreases. Since WHAs are difficult to machine, an additional objective of the study is to optimize machining parameters. An optimal balance of the experimental cutting parameters using Grey relational analysis has been achieved, which can be effectively employed for the machining of the alloys with close dimensional tolerances and desirable surface finish

Stress-strain characteristics and energy absorption analysis of Construction and demolition waste recycled aggregate concrete in compression

The stress strain characteristics and mechanical properties of construction and demolition aggregate concrete at two different w/c ratios – 0.4 and 0.5 are presented in this study. The mechanical and stress strain characteristics of recycled aggregate concrete are compared to the properties and Stress strain characteristics of the conventional aggregate concrete. The mechanical properties include the cube and cylindrical compressive strength, Modulus of elasticity, flexural strength, split tensile strength and hardened density. Under stress strain characteristics, strain at peak stress and the energy absorbed under compression is included. The study aimed to correlate and compare the behaviour of recycled aggregate concrete and Conventional aggregate concrete having comparable strength. Finally, the experimental stress strain characteristics of the Recycled aggregate concrete is analysed for its compatibility of the assumed stress strain behaviour of concrete in IS 456. According to the findings, recycled aggregate concrete has similar stress-strain characteristics to conventional aggregate concrete of comparable strength, and existing stress block parameters can be suitably used for the recycled aggregate concrete

Feasibility of using ultrasonic technique to measure the blast furnace lining thickness

Blast furnace process has been the most effective way to produce iron for over 200 years.Throughout the years, large efforts have been put on finding ways to increase the productivity and extend the campaign length. The condition of the refractory lining of a blast furnace plays a very important role to determine its campaign length. Many methods have been employed to measure blast furnace lining thickness including radioisotopes, thermal measurement and core-drilling. Temperature measurement is among the most widely used method for on-line monitoring the profile of the blast furnace inner surface, which is based on numerically solving inverse problem using heat transfer models and readings from thermocouple. Optimization methods are applied to obtain the boundary of the domain iteratively, and hence the computation is very expensive and calculation cannot be very accurate. This paper presents the feasibility of using non-invasive ultrasonic technique in bistatic mode to measure the profile of the refractory liner of the hearth region of blast furnace

Impact of ISO: 17020 for Quality Assurance System in Construction Sector

The objective of the paper is to analyze the various factors and loop holes that have a significant impact on effectiveness of quality and quality assurance system and to suggest recommendations to increase the quality performance of the construction projects. The paper also highlights the difference in Quality Assurance system of projects wherein ISO: 17020 is not implemented and the project wherein it is implemented.  In the current paper, National Council for Cement and Building Materials, India monitored 30 construction projects were selected with a construction cost between five to thirty Crores covering 15 project with ISO:17020 procedures and 15 project without ISO:17020 procedures. The data was collected from these projects on various quality and management related aspects. These projects cover structures such as school buildings, community hall, hostel block, convention centers etc. The study was conducted for construction projects of different government bodies. This analysis has been mainly done covering the factors playing key role in quality of a structure during construction such as client’s commitment towards quality, quality of material, documentation, work practices, personnel etc. Based on the data analysis, quality assurance system for these projects were categorized as Excellent, Good, Average and Poor in Quality Grading based on the various factors that directly or indirectly affects the quality and smooth functioning of project during and post construction. The difference in implementation of quality system with and without ISO: 17020 is highlighted in the paper

Comparison of locking compression plating vs retrograde intramedullary nailing in distal femur extra-articular fractures

Background: The purpose of the study was to compare the outcome of distal femur extra articular fractures treated with locking plate and retrograde intramedullary nail.Methods: 86 patients’ distal femur extra-articular fractures were included in the study. 44 patients were operated with intramedullary nailing; 42 patients were operated with locking plate. Results of the 2 groups were compared with regards to clinical and radiological outcome, intraoperative timing and blood loss. Post-operative status of the patients was evaluated using the visual analogue scale, neer score, knee range of motion and radiological union on plain radiographs. Patients were followed-up at 4 weekly intervals from 8 to 28 weeks and then at 1 year.Results: Mean operative time and blood loss was less in intramedullary nailing group whereas intraoperative blood loss was less in the plating group. 6 patients developed surgical site infection in the plating group. Mean-time till radiological union was significantly better in intramedullary nailing group. 7 patients in plating group had issues with union (5 non-union, 2 delayed union) whereas 1 patient in IMN group had nonunion. 93% of intramedullary nailing cases were able to bear full weight at 12 weeks compared to 66% cases in plate group. Knee pain at 6 months was more in intramedullary nailing group.Conclusions: IMN proved to be a better modality of fixation of distal femur fracture fixation in our study in terms of operative time, union rates, infection rates and overall patient outcome if done with proper principles and techniques of intramedullary fixation