International Conference on Materials and Manufacturing Engineering

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Authors: Md Shad Rahman, Rasel A. Sultan, N.M. Hasan
Abstract: This system is designed for advance Robotic control. It based on sensor data acquisition and software data processing. With those systems controlling a robotic hand by hydraulic and electric means. It is separated by two different sections. First, data acquisition section with differential sensor data (Gyro sensor, Flex sensor, Pressure sensor). Second, software processed data application system consisting of robotic hand. Specialty of this system is it gives precise control of robotic arm following human hand movement. It also gives touch and pressure feelings in robotic hand. A lot of work can be done easily with the help of it. Like this system gives remote bomb disposal, hazardous environmental work remotely, remote operation, remote medical help and so on.
Authors: S.M. Mahbobur Rahman, Kazi Ehsanul Karim, Md Hasan Shahriar Simanto
Abstract: In engineering metallurgy, heat treatment of steels is one of the most important factors as it enhances various physical and mechanical properties which are considered handy in numerous structural applications. Heat treatment is basically the combination of operations involving the heating and cooling of a metal or alloy in solid state for obtaining required microstructures by refining the grain size and a combination of properties. The prime object of this investigation is to illustrate the effect of heat treatment on low carbon steel (AISI 1020) to expose its mechanical (hardness) and microstructural (microstructures) properties. For this purpose, cylindrical shaped AISI 1020 steel specimens were used. The samples were polished using a specimen polishing machine and heated in a heat treatment furnace at approximately 950°C for almost 2 hours and then cooled by different quenching media (Water, Air, Ash). After heat treatment (Hardening, Normalizing, Full Annealing) the Brinell hardness number (B.H.N) was determined using a Universal testing machine (U.T.M) and the microstructures were examined using a metallurgical microscope. It was observed that, due to hardening the resultant structure was a super saturated solid solution of carbon trapped in a body centered tetragonal structure called martencite which increased the hardness number of the steel specimens drastically making an extreme harder steel. Moreover, full annealing provided lower hardness value due to the presence of ferrite structure and normalizing provided moderate hardness value and ductility due to slow cooling.
Authors: A.M.M. Sharif Ullah, M.A.K. Chowdhury, Akihiko Kubo
Abstract: This paper presents a surface generation mechanism of grinding that captures the microscopic interaction between the abrasive grains and work-surface. The mechanism utilizes both deterministic and stochastic formulations and deals with such realistic constraints as loss/wear and uneven distribution of abrasive grains, roughness of already-ground work-surface, and machine stiffness. Apart from the theoretical treatments, numerical examples are cited showing how the topography of the work-surface evolves because of the proposed mechanism. The work will help build computerized systems ensuring a reliable prediction of the surface roughness due to grinding under the realistic constraints.
Authors: Md Arifuzzaman, Ho Sung Kim
Abstract: Flatwise compression and flexural behaviour of perlite/sodium silicate composites made of expanded perlite and sodium silicate is studied using a new manufacturing method for applications of sandwich foam core materials. Sodium silicate content in composites (a perlite particle size of 2-3mm) was varied for a range of 0.1 - 0.3 g/ml and compaction ratio for moulding for a range of 2.0 - 3.0. Specimens under flatwise compression were found to be more capable for energy absorption than those previously reported for lengthwise compression, ascribing to appearance of densification stage following the initial cracking. Also, under flexural loading, energy absorption in composites after the initial cracking was found to be in operation, supporting their candidacy for wide applications where gypsum boards are dominant. It was deduced from both flexural testing results and fracture mechanism that compressive strength is higher than tensile strength, suggesting the future directions of mechanical performance improvement.
Authors: Niladri Pratap Maity, Rajiv R. Thakur, Reshmi Maity, R.K. Thapa, S. Baishya
Abstract: In this paper the interface trap densities (Dit) are analyzed for ultra thin dielectric material based metal oxide semiconductor (MOS) devices using high-k dielectric material Al2O3. The Dit have been calculated by a novel approach using conductance method and it indicates that by reducing the thickness of the oxide, the Dit increases and similar increase is also found by replacing SiO2 with Al2O3. For the same oxide thickness SiO2 has the lowest Dit and found to be the order of 1011 cm-2eV-1. The Dit is found to be in good agreement with published fabrication results at p-type doping level of 1 × 1017 cm-3. Numerical calculations and solutions are performed by MATLAB and device simulation is done by ATLAS.
Authors: Niladri Pratap Maity, Reshmi Maity, R.K. Thapa, S. Baishya
Abstract: In this paper, an analytical model for evaluation of tunneling current density of ultra-thin Metal Oxide Semiconductor (MOS) devices is presented. Results have been obtained for a wide variation of oxide thickness and biasing condition having doping concentration of 1 x 1017 cm-3. The investigation for the tunneling current density is limited to low temperatures, so that any thermal involvement to current flow can be neglected. The self-consistent oxide tunneling model has been used for device simulation, which is simple to implement and assist in the study of deep sub-micron MOS gate current effects, therefore correctly calculate the terminal current. Tunnel resistivity is also evaluated utilizing this tunneling current density model. Theoretical predictions are compared with the results obtained by the 2-D numerical device simulator ATLAS, good agreements between the two are observed.
Authors: Reshmi Maity, Niladri Pratap Maity, R.K. Thapa, S. Baishya
Abstract: The generation and detection of ultrasound in air has many applications in the field of ranging, non-destructive evaluation, microscopy and the most impactful in medical imaging. Conventional designs of electrostatic transducers have large electrode spacing of 50-100 μm which reduces the sensitivity of these capacitors. In the last one and a half decade silicon micromachining is used to define capacitors with gap spacing as small as 500Å, making it possible highly efficient capacitive micromachined ultrasonic transducers (CMUTs). In this paper a CMUT element is analytically characterized and FEM simulated. The observations are compared with published experimental results and excellent agreement is found between them.
Authors: Reshmi Maity, Niladri Pratap Maity, R.K. Thapa, S. Baishya
Abstract: Silicon micromachining techniques developed over the last few decades’ aid in precise control over nanometer scale structures. Using these techniques to fabricate transducer elements with small electrode spacing efficient and broadband ultrasonic air transducers can be made. In this paper frequency response profile of a circular capacitive micromachined ultrasonic transducer (CMUT) element with silicon nitride as the membrane material is analytically modelled and compared with FEM simulation results. It is observed that the resonance frequency is highly dependent on the membrane material and structural properties. Silicon nitride serves as an excellent material for generation and detection of ultrasonic waves in air. The results are compared with published experimental values and appreciable agreement is obtained.
Authors: Ritwik Basu, Jerzy A. Szpunar, Mostafa Eskandari
Abstract: The study presents a comparative evaluation on microstructural modifications of a ternary Ni―Ti―Fe alloy deformed through two different routes of deformation through equal reduction in thickness. These deformation modes were (1) conventional cold rolling and (2) marforming (rolling in liquid nitrogen). The final annealing treatments were kept identical for both processes. Considerable differences in microstructures were brought out through aforementioned deformation modes. Marforming of the alloy led to significant grain refinement as against conventional cold rolling, revealed through electron backscattered diffraction (EBSD) studies.

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