Abstract: The present work deals with the optimization of micro-WEDM process parameters for machining Ti49.4-Ni50.6 shape memory alloy (SMA) for orthopedic implant application. Effect of micro-WEDM parameters viz. Gap voltage, capacitance, wire feed and wire tension on the response variables such as material removal rate, surface roughness, kerf width and dimensional deviation is determined. As Ti-Ni SMA has fascinating properties and bio-compatibility, have been considered for present work. Nine experiments have been performed on micro-WEDM based on an orthogonal array of Taguchi method. Subsequently, the grey relational analysis (GRA) method is applied to determine an optimal set of process parameters. It is observed that optimized set of parameters A3B3C3D1 viz. 140 V gap voltage, 0.4 µF capacitance, wire feed 30 µm/sec and 30% of wire tension determined by using GRA offers maximum MRR and minimum SR, KW and DD. From the Analysis of Variance, it is seen that the process parameter capacitance is the most significant parameter for multi-response optimization with a percentage contribution of 77.91%. Young’s modulus also checked for biocompatibility. Also, SEM images are taken to confirm the results offering better surface quality. Heat treatment process like annealing is found to be the most suitable to recover shape memory effect of WEDMed samples.
Abstract: The peculiar feature of friction materials to absorb the kinetic energy of rotating wheels of an automobile to control the speed makes them remarkable in automobile field. The regulation of speed cannot be achieved with the use of single phase material as a friction material. Consequently, the friction material should be comprised of composite materials which consist of several ingredients. Incidentally, the friction materials were formulated with friction modifier, binders, fillers and reinforcements. Due to its pleasant physical properties, asbestos was being used as a filler. Past few decades, it is found that asbestos causes dangerous cancer to its inhaler, which provides a scope its replacement. Several attempts have been made to find an alternative to the hazardous asbestos. The efforts made by different researchers for the impact of every composition of composite friction material in the field are reviewed and studied for their effect on the properties of friction material. Surface morphological studies of different friction material are compared to interpret the concept of surface wear and its correlation with material properties.
Abstract: The aim of the this study to determine optimal process parameter for the hardness of direct metal laser sintering (DMLS) process as the hardness plays a significant role in to DMLS made components and die or mould. In this manner, research is focused around determining the effect of process parameters like laser power, scanning speed, layer thickness and hatch spacing on the hardness of CL50WS (maraging18Ni300 steel) material. A response surface methodology based numerical model was proposed to predict hardness, and the adequacy of the created model was checked through the analysis of variance technique. Additionally, optimized conditions were set up to maximize the hardness through the desirability function theory.
Abstract: The use of agricultural wastes and natural materials in new technologies is a novel subject. Consequently, an attempt has been made to formulate a synthetic fluid using an organic water, Water Extract from Fermented Ground Maize (WEFGM) and compare its performance with water-based sample in turning operation using a mild steel as workpiece. Two samples of synthetic fluids were formulated from each of deionized WEFGM, ordinary WEFGM and deionized water as base-fluids at two composition (5 and 10%vol) levels of selected additives. The results of experimental analysis of heat transfer properties of these synthetic fluids exist, hence the need to ascertain the actual performance output. Temperature-Time Gradient (TTG) which is a rate of temperature drop (heat withdrawn) from the work zone was used as evaluation parameters. The result showed that deionized WEFGM is the most efficient of the entire samples at both compositions with an average TTG of 3.61 and 2.16 °C/min at 10 and 5% additive concentration respectively. At lower additive concentration which is more economically advantageous, the performance rating is deionized WEFGM>>WEFGM>>deionized Water. This implies that WEFGM is more effective than water as a base fluid for synthetic fluid in performance as it has been previously so reported in properties. Meanwhile, T-test statistical analysis (using IBM SPSS 23) shows that there is highly significant difference in TTG at each time of application of individual fluid (p<0.05). However, TTG of one fluid sample is not significantly different from the other (p>0.05) implying that the fluids can all work as coolants and relatively have comparable performance output.
Abstract: This paper discusses the potentials of different wood constructions for the renovation and extension of existing buildings for sustainable urban renewal. The renovation and extension of existing buildings with wood constructions can contribute significantly to sustainable urban redevelopment. The renovation of building envelopes, such as façades and roofs, with highly insulated wooden components, can reduce the transmission heat losses and related heating energy demand of existing buildings significantly. The extension of existing buildings contributes to the redensification of urban areas and can create synergies with the improvement of existing buildings’ performances. The manifold advantages of specific wooden constructions can be related to different aspects, such as construction type and material properties, building execution, design, logistic and sustainability. The results of this research discuss the architectural design and planning relevant properties of specific timber construction types, such as wood frame, cross-laminated timber (CLT), massive timber, and hybrid timber-concrete, considering the properties of different soft (such as spruce) and hard (such as beech) construction timber species. Timber constructions are compared with conventional massive constructions out of concrete and steel. The results confirm the significant advantages of timber constructions regarding all aspects.
Abstract: Experimental investigations on the early age, strength gain properties of fly ash blended cement concretes containing low and high volume fly ash replacement were studied. Concrete mixes were prepared with two different fly ash contents and varying concrete ingredients with water to binder ratio (w/b), fine to coarse aggregate ratio (F/c) and accelerator dosage. Five different curing techniques, namely controlled humidity curing; hot air oven curing, steam curing, hot water curing and normal water curing were adopted for curing the fly ash based concretes. Test results showed evidence the influence of accelerating admixtures and accelerated curing for obtaining the high early strength properties in fly ash mixed concrete. Most notably a maximum 1 day compressive strength of 40.20 MPa and 34.60 MPa with low (25%) and high (50%) volume fly ash concretes were obtained respectively in this study. Experimental results clearly indicated that the improvements on the strength gain properties with the careful selection of mix ingredients; accelerator addition and accelerated curing in fly ash based concrete mixes. Also, significant improvements on the flexural strength, elastic modulus, dynamic modulus and the ultrasonic pulse velocity test were noticed.
Abstract: The study aims to explore the effects of crimped polypropylene fiber (PP) inclusions in slag (GGBS) based concrete, which was used as cement replacement. The mode of accelerated curing on mechanical properties of the GGBS based concrete for various mixes of concrete was investigated systematically. The addition of PP fiber in the concrete increases the strain hardening properties of the concrete due to matrix reinforcing efficiency offered by discrete fibers present in the matrix. The experimental test results showed an increase in bending stress in concrete with an increase in percentage of PP fibers from 0.1% to 0.3% Vf of concrete. In the case of slag concrete, the optimum addition of slag up to 25% proved to be effective in improving the concrete strength properties. Further replacement of OPC in GGBS up to 50% concrete mixes showed a reduction in the compressive strength in normal curing. Indeed, an apparent increase in the compressive and flexural strength of slag based concrete was noticed in accelerated curing for various mixes of structural concrete.