Effect of Operating Parameters on Electrochemical Deposition of Metallic Thin Film in Presence of Ultrasound

Due to their small size and thickness, nanostructured thin films exhibit novel properties which largely differ from the bulk materials. Due to their significant properties it can be used as microelectronic materials, bacteriostatic materials, catalytic materials or magnetorecording materials, antibacterial materials, cryogenic superconducting materials, biosensor materials. Generally the shape, size, and size distribution of particulates and grains can be controlled by adjusting the reaction condition such as external and internal parameters like temperature, electrolyte concentration, current density, PH of the solution. Sonoelectrochemistry is the study of the effects of the combination of ultrasonic radiation with electrode processes occurring at surfaces of electrodes immersed in a solution in an electrochemical cell. The ultrasound plays an important role to produce cavitation bubbles inside the electrolyte by rupturing the chemical bonds between molecules and electrolyte. The cavitation bubbles implosively collapse within a very short time after undergoing the formation growth and contraction. Synthesis under low temperature may avoid undesirable interdiffusion between adjacent layers and structures and allows uniform modification of surfaces and structures with reduced grain size. In this work we prepare the copper thin film by sonoelectrosynthesis method. The grain size, mechanical and electrical properties of the electrodeposited metal thin film depends upon various parameters like temperature, PH, current density, and concentration of electrolyte and also ultrasound has many numerous effects on the grain size, hardness, porosity and brightness of the deposits. This particle can characterized by XRD, SEM, AFM, DSC and study the mechanical properties by nanaoidentation.

An experimental investigation on metallurgical and corrosion behavior of atmospheric plasma sprayed Stellite 6 powder on AISI 304 stainless steel

An experimental investigation was undertaken to study the Cobalt-based Stellite 6, powder deposited on SS 304 stainless steel substrate without any intermittent layer using an atmospheric plasma spray deposition process by varying the thickness of coating in the range of 74 µm, 128 µm, and 215 µm. The effect of coating thickness on metallurgical properties and corrosion resistance behavior was investigated. Optical microscopy, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS) were employed to study the morphology of Stellite 6 coating. X-Ray Diffraction was used for structural analysis and to identify the phase formation. It was observed that the sample with 128 µm coating thickness provides the best result concerning microhardness and microstructure characteristics whereas the sample with 215 µm coating thickness provides the best corrosion resistance property. The reasons for the deviation were investigated and the factors responsible for the deviation were assigned in this investigation

Do anchor investors create value for initial public offerings? An empirical investigation

The concept of anchor investors was introduced by the market regulator, Securities Exchange Board of India (SEBI), to bring transparency in the book building mechanism. We examine anchor investors' investment in initial public offerings (IPOs) to determine how they create value for issuing firms and participating investors. Using a database of 135 IPOs issued in the Indian market through book building mechanism during 2009–2014, we find that anchor investors' investment in IPOs reduces underpricing. Larger subscription from retail investors for anchor-supported IPOs indicates that anchor investors' participation is viewed as a credible attestation of quality of the issue. We document that anchor-supported IPOs are more liquid and less volatile in the short run. We also find that by controlling for other factors such as offer size, subscription rate and age of the firm, a part of the underpricing is reduced by anchor investors

Post-issue promoter groups holding, signalling and IPO underprice: evidence from Indian IPOs

This paper attempts to specify the relationship between post-issue promoter groups' retention and Initial Public Offering (IPO) underprice. We also investigate the impact of signalling and financial variables, i.e. offer size, times subscribed, age of the firm, book value, leverage, market volatility and ex-ante uncertainty along with post-issue promoter groups holding on IPO underprice. On using a sample of 92 IPOs, we find IPOs are underpriced at an average of 46.55% during 2002 to 2006. We document a positive relationship between post-issue promoter group holding and IPO underprice. Our results indicate offer size, times subscribed and post-issue promoter group holding are statistically significant in explaining underprice. We also document positive initial day return for IPOs across all industries, while manufacturing sector IPOs are less underpriced than non-manufacturing sector IPOs.IPO underprice; initial public offering; post-issue promoter groups holding; signalling; offer size; age; book value; ex-ante uncertainty; times subscribed; leverage; volatility; India; manufacturing IPOs.

Thermo-mechanical modeling and validation of stress field during laser powder bed fusion of AlSi10Mg built part

Direct metal laser sintering process is a layer based laser powder bed fusion additive manufacturing process used to fabricate near net shape metallic components directly from the metal powders. A high energy moving heat source is utilized to melt and fuse the powders in subsequent layers. During the direct metal laser sintering additive manufacturing process, rapid heating and cooling take place which results in an unexpected change in temperature in the scanned layers. This change in temperature induces thermal stresses in the build part after the accomplishment of the process and it can be destructive to the quality and performance of the build parts which hinders its end-user applications. In the present study, a comprehensive thermo-mechanical model has been developed for the purpose of investigating thermal residual stress in the AlSi10Mg single layer build part during the direct metal laser sintering process using finite element method. Further, the model has validated analytically by measuring the thermal strain. In addition, the effects of scan speed and laser power on the development of thermal residual stresses were investigated. It is found that repeated thermal expansion and contraction in the powder bed leads to the development of thermal residual stress and thermal stain in the build part. The finding of this study will help to optimize the processing conditions for minimizing the thermal residual stress in the build part to enhance its end user application. Keywords: Direct metal laser sintering, Thermal residual stress, Additive manufacturing, Thermo-mechanical modeling, Finite element analysis, Temperature distributio

Perception of beneficiaries for efficacy of MGNREGA: a micro level analysis from Kalahandi district of Odisha, India

The present study tries to examine the impact of MGNREGA (Mahatma Gandhi National Rural Employment Guarantee Act) on socio-economic status of MGNREGA beneficiaries in Kalahandi district of Odisha, India by using both primary and secondary data.Secondary data are collected from official website of MGNREGA during the period from 2012-2013 to 2018-2019. Primary data collected through semistructured questionnaire from two blocks of the district, namely Golamunda and Narla with the total sample size of 300 households. In selecting the sample households, a proportionate sampling along with simple random sampling technique has been used. For analysis of the study, a five-point Likert scale has been used to measure the perception of sample respondents on the improvement of socio-economic conditions after implementation of MGNREGA. Besides, composite index has been used to capture the combined perceptions of all the sample respondents. The study found that less than 10 % of the target household got employment of 100 days during the study period. Besides, the result of composite index (0,16) regarding the perception of MGNREGA beneficiaries on different socio-economic parameters gives an impressive that MGNREGA is less effective in the improvement of socio-economic status of the beneficiaries. Thus, it can be concluded that the MGNREGA has not been effective in improving the socio-economic status of MGNREGA beneficiaries in Kalahandi district of Odisha.El presente estudio trata de examinar el impacto del programa MGNREGA (Mahatma Gandhi National Rural Employment Guarantee Act) en el nivel socioeconómico de sus beneficiarios del distrito de Kalahandi (Odisha, India), utilizando datos primarios y secundarios. Los datos secundarios se recopilan delaweb oficial del programa MGNREGA desde el año 2012-2013 al 2018-2019. Los datos primarios se recopilaron a través de un cuestionario semiestructurado pasado en dos bloques del distrito (Golamunda y Narla), con un tamaño de muestra total de 300 hogares. Estos se seleccionaron mediante un muestreo proporcional junto con una técnica de muestreo aleatorio simple. Para el análisis se utilizó una escala Likert de cinco puntos con la que medir la percepción de los encuestados de la muestra sobre la mejora de las condiciones socioeconómicas después de la implementación del programa MGNREGA. Además, el índice compuesto se ha utilizado para capturar las percepciones combinadas de todos los encuestados. El estudio encontró que menos del 10 % de los hogares encuestados consiguió empleo durante los 100 días que duró nuestro estudio de programa. Además, el resultado del índice compuesto (0,16) con respecto a la percepción de los beneficiarios de MGNREGA sobre diferentes parámetros socioeconómicos, permite apuntar que el programa MGNREGA es relativamente poco efectivo