Friction Buttering: A New Technique for Dissimilar Welding

This work offers a fresh perspective on buttering, a technique often considered for fusion welding of dissimilar metals. For the first time, buttering was attempted in solid state using friction deposition. Using this new “friction buttering” technique, fusion welding of two different dissimilar metal pairs (austenitic stainless steel/borated stainless steel and Al-Cu-Mg/Al-Zn-Mg-Cu) was successfully demonstrated. The results show that friction buttering can simplify a tough dissimilar welding problem into a routine fusion welding task.     

Study of Non-lubricated Wear of the Al–Si Alloy Composite Reinforced with Different Ratios of Coarse and Fine Size Zircon Sand Particles at Different Ambient Temperatures

In the present work, a detailed study of ceramic reinforcement of different size ranges in the matrix of LM13 alloy on the friction and wear behavior has been carried out. For this purpose, LM13/Zr composite containing 10 wt% zircon sand particles of different size ranges using stir casting process has been developed. Zircon sand particles were incorporated in two ways: firstly as single size reinforcement and secondly dual size reinforcement. Durability of the composites was tested by finding the wear rate of the composite against the steel disk by pin-on-disk method. Addition of zircon sand particles in the LM13 alloy improves the hardness of the composite as well as wear resistance. Wear rate of the developed composites was tested under different test conditions by varying the applied load and ambient temperatures. Wear rate of the composite changes significantly at different ambient temperatures. SEM analysis of the worn surfaces was done to know the operative wear mechanism.     

Evaluation of Optimal River Training Work Using GA Based Linked Simulation-Optimization Approach

Use of structural measures for controlling a river to minimize its devastating effect and to utilize it for the benefit of mankind is a common practice all over the world. Because of high investment, such measures require prior investigation through model study. As lab based physical model study is very expensive and time consuming, mathematical modeling is generally used for investigating different alternatives of river training works. In this study, a new approach is proposed for deciding appropriate river training measure in a particular reach of a river or channel. In this methodology, an optimization model is linked with the hydrodynamic model for obtaining cost effective combination of groynes which will maintain a user defined flow speed in a pre-decided portion of a river reach. The optimization model is developed using binary coded Genetic Algorithm (GA) and the flow simulation model uses the Beam and Warming scheme for solving the two dimensional (2D) hydrodynamic equations of unsteady flow. The performance of the model is tested by applying the methodology in a rectangular channel for attaining different target speed values at a pre-defined portion of the channel and logical results have been obtained for all the tested scenarios.     

Optimization of processing parameters of medium density fiberboard using response surface methodology for multiwalled carbon nanotubes as a nanofiller

In the present work, medium density fiberboard (MDF) panels were produced using multiwalled carbon nanotubes (MWCNT) reinforced urea formaldehyde resin. Response surface methodology was employed to optimize the relationship between the three variables, viz. pressing time, percentage of UF resin and percentage of MWCNT, used in the fabrication of MDF, and the influence of variables on the internal bonding (IB) and modulus of rupture (MOR) was studied. The optimum conditions based on the IB strength were determined as 8.18 % of UF resin, pressing time of 232 s, and MWCNT of 3.5 %. Similarly, the optimized conditions for MOR are also reported in this paper.     

Recovery of metals and other beneficial products from coal fly ash: a sustainable approach for fly ash management

International Journal of Coal Science & Technology - Increasing production and disposal of coal fly ash (CFA) is a matter of serious environment concern. However, CFA contains various...     

Physical Effects of Variable Thermophysical Fluid Properties on Flow and Thermal Development in Micro-Channel

Micro-scale cooling is an efficient and effective cooling technique to achieve the goal of higher heat removal capabilities. The present research focuses to find the physical effects of fluid property variations on flow and thermal development in micro-channel. The effects of temperature-dependent density, viscosity, and thermal conductivity variations on single-phase laminar forced convection are numerically investigated. The problem is especially simulated for hydrodynamically and thermally developing water flow in micro-channel with no-slip, no-temperature jump, and constant wall heat flux boundary conditions. It is observed that the density variation induces radially inward flow due to continuity, which sharpens the axial velocity profile and decreases Nusselt number compared to constant property solution. The axial velocity profile significantly alters due to viscosity variation. This alteration varies along the micro-flow and it induces radially flow due to flow continuity. The reducing rate of Nusselt number for viscosity variation is substantially lower than constant property solution due to a significant flattening effect of the axial velocity profile, which augments the Nusselt number. Thermal-conductivity variation across the flow induces radial conduction, which enhances convection compared to constant property solution. Additionally, the effects of thermophysical fluid property variations on static gauge pressure drop are also investigated.     

In vitro ageing and wear behaviour of ceria stabilized zirconia toughened alumina (CSZ-TA) bio-ceramic

15–25 wt% zirconia (stabilized with 14 mol% ceria) toughened alumina was synthesized by co-precipitation technique. The synthesized powders were calcined at different temperatures, compacted and conventionally sintered following two steps sintering process. Uniformly distributed submicron sized grains with Vickers' hardness value up to 1730±6HV20 were achieved after conventional sintering. In order to assess the ageing behaviour, samples were hydrothermally treated (in vitro) at 134 °C under 0.2 MPa in presence of simulated body fluid. Rietveld refinement of the X-ray diffraction patterns was carried out to estimate the phase content after calcination, sintering and after different stages of hydrothermal treatment. No significant phase change (only ∼3%) was observed even after 100 h of hydrothermal treatment. Very few bulged grains (resulted from the tetragonal to monoclinic phase transformation) on the surface and slight decrease in hardness value were observed after hydrothermal treatment. Fretting wear in dry condition was carried out taking ball on flat geometry for 10⁵ cycles at different loads before and after hydrothermal treatment. Wear volumes were directly estimated from the surface scanning of the wear scar using profilometer. Transition of wear and its related mechanisms at different loads along with the effect of ageing on wear were discussed.