Mechanization and Import Substitution in Zimbabwean Farmers' Equipment: A Case Study of the Revitalization of an Abandoned Tractor Trailer
Drill String Vibrational Analysis and Parametric Optimization for a Portable Water Well Rig Development
An Efficient Deep Neural Network with Amplifying Sine Unit for Nonlinear Oscillatory Systems
The Occupational Directness of Nanorobots in Medical Surgeries
Recent Trends in Solar Thermal Cooling Technologies
Design of Oil-Ammonia Separator for Refrigeration Systems
A Review on Mechanical and Tribological Characteristics of Hybrid Composites
Design and Experimental Investigation of a Natural Draft Improved Biomass Cookstove
Progressive Development of Various Production and Refining Process of Biodiesel
Optimization of Wire-ED Turning Process Parameters by Taguchi-Grey Relational Analysis
Evaluation Of Mechanical Behavior Of Al-Alloy/SiC Metal Matrix Composites With Respect To Their Constituents Using Taguchi Techniques
Multistage Extractive Desulfurization of Liquid Fuel by Ionic Liquids
Isomorphism Identification of Compound Kinematic Chain and Their Mechanism
Development of Electroplating Setup for Plating Abs Plastics
A Comprehensive Review of Biodiesel Application in IDI Engines with Property Improving Additives
The catching trend of using MEMS (Micro-Electro Mechanical System) devices in several crucial applications has mediated the need of careful investigation into the mechanisms that affect the performance of these devices. Dissipation of energy through damping is one such aspect that is important in devices using vibrating structures. For high Q MEMS resonators that are operated in vacuum, Thermo-Elastic Damping (TED) is a fundamental & crucial dissipation mechanism. In the present contribution, a brief overview has been presented to provide an update on the historical evolution of this concept- starting from identification of this phenomenon to an important source of internal friction, development of the set of governing equations, to extending the theory to Non-Fourier heat conduction. Prominent effects of the design factors such as the operating frequency of the device, its shape & size, material etc. on the Thermo-elastic damping have been explored & presented here. Approach for minimizing such dissipation has also been suggested for improving the Q-factor of the devices.
Friction Stir Welding (FSW) is an innovative and promising solid state joining process invented by The Welding Institute (TWI). FSW is considered to be one of the most significant developments in metal joining technology over the last two decades. Experiments were conducted on 6 mm thick AA7075 aluminum plates with copper coating on the faying surfaces. The plates were joined by friction stir welding under optimized conditions and the weldments were investigated for mechanical and metallurgical properties to identify the influence of the intermetallic compound (IMC) formed during the process. Results show substantial improvement in mechanical and metallurgical properties with copper coated weldments over conventional weldments. Crack initiation and specimen fracture were observed in the thermo mechanically affected zone of the weldmentS with superior tensile strength, finely elongated grains and reduced defects.
Demand for production of durable mechanical components at lower cost has been on the rise. Mechanical components subjected to aggressive conditions suffer from degradation of surface properties through several modes like wear, corrosion, and oxidation. The challenge to the industries is to develop wear resistant coatings with good surface properties in a shorter processing duration. In the present work an innovative process has been explored for development of metallic cladding. A Ni based cladding has been developed on austenitic stainless steel substrate (SS—316) by the exposure of microwave irradiation. The microwave hybrid heating technique has been used for the development of cladding. The developed clads have been characterized through X—ray diffraction (XRD), field emission scanning electron microscope (FE—SEM), and Vicker’s microhardness. The clad of thickness ~1mm has been developed using microwave radiation of power 900W at 2.45GHz frequency for the duration of 360s. The XRD results revealed the precipitation of chromium carbide in the developed clad with other phases of NiSi and FeNi3. The transverse section of developed cladding shows good metallurgical bonding with substrate by partial mutual diffusion of elements. The clad is free from cracks and has significantly less porosity (1.01%). The average microhardness of developed clad is ~300Hv.
A comprehensive understanding of the materials and their processing helps efficient fabrication of component in micro devices such as microelectromechanical systems (MEMS). Silicon is one of the widely used materials to create many integrated circuits used in consumer electronics in the modern world. Glass and titanium are two other materials widely used in fabrication of MEMS which usually exhibit very high degree of reliability. However, one of the most challenging tasks for MEMS industries is to find new methods for machining such difficult-to-process materials. This paper explores a non-thermal and non-chemical approach to machine these materials using ultrasonic micromachining (USMM). In the current work, microdrilling was carried out on silicon, glass and titanium using USMM. Machinablity aspects while drilling holes have been analysed in terms of study of surface roughness and tool wear. The process yielded a surface finish upto 2.08µm, while the highest tool wear among the attempted materials was observed while machining relatively ductile titanium. The study proves the viability of micro drilling of the target materials with parametric analysis. A brief review of different materials used for MEMS, their suitability and processing challenges has been presented.
The matrix alloy Al 6061 contributes very large values of yield strength, ultimate tensile strength, ductility and bending force to the Al-alloy/SiC metal matrix composites. The matrix alloy 7072 exhibits lower ductility to the Al-alloy/SiC metal matrix composites than the matrix alloy Al 6063. Mg improves the wettability between Al and SiC particles by reducing the SiO2 layer on the surface of the SiC. The SiC particles are distributed unevenly in the as-cast composite with no distinct evidence of clustering but very little agglomeration. MgO and MgAl2O3 are formed along the grain boundaries. The phases Al2Cu, Mg2Si, , and are also observed in the microstructures of Al-alloy/SiC composites. With increasing volume fraction, more load is transferred to the reinforcement which results in a higher yield strength, ultimate tensile strength, and bending force to the Al-alloy/SiC composites. The decrease in ductility can be attributed to the earlier onset of void nucleation with increasing amount of reinforcement in Al-alloy/SiC metal matrix composites. The decrease in the particle size increases the yield strength, ultimate tensile strength, bending force, and ductility (tensile elongation).
Dry machining is a machining process without coolant and it has more popular as a finishing process. The purpose of this paper was to obtain a comprehensive understanding of the relationship between input data i.e. speed, feed and depth of cut and output data i.e. residual stress during dry machining with CBN cutting tool on hardened steel [En31]. In present study L27 orthogonal array test plan was used. Neuro fuzzy model [CANFIS] is developed and sensitivity analysis is carried out to measure the relative importance of the input parameters of the model and how the model output parameter varies in response to variation of an input.
