Microstructures and Mechanical Properties of Ti6Al4V Parts Fabricated by Selective Laser Melting and Electron Beam Melting

This work compares two metal additive manufacturing processes, selective laser melting (SLM) and electron beam melting (EBM), based on microstructural and mechanical property evaluation of Ti6Al4V parts produced by these two processes. Tensile and fatigue bars conforming to ASTM standards were fabricated using Ti6Al4V ELI grade material. Microstructural evolution was studied using optical and scanning electron microscopy. Tensile and fatigue tests were carried out to understand mechanical properties and to correlate them with the corresponding microstructure. The results show differences in microstructural evolution between SLM and EBM processed Ti6Al4V and their influence on mechanical properties. The microstructure of SLM processed parts were composed of an α′ martensitic phase, whereas the EBM processed parts contain primarily α and a small amount of β phase. Consequently, there are differences in tensile and fatigue properties between SLM- and EBM-produced Ti6Al4V parts. The differences are related to the cooling rates experienced as a consequence of the processing conditions associated with SLM and EBM processes.     

Unification of MOS compact models with the unified regional modeling approach

This paper reviews the development of the MOSFET model (Xsim), for unification of various types of MOS devices, such as bulk, partially/fully-depleted SOI, double-gate (DG) FinFETs and gate-all-around (GAA) silicon-nanowires (SiNWs), based on the unified regional modeling (URM) approach. The complete scaling of body doping and thickness with seamless transitions from one structure to another is achieved with the unified regional surface potential, in which other effects (such as those due to poly-gate doping and quantum-mechanical) can be incorporated. The unique features of the Xsim model and the essence of the URM approach are described.     

Experimental and theoretical studies of anti-ulcer drugs with benzimidazole rings as corrosion inhibitor for copper in 1 M nitric acid medium

The adsorption effect of esomeprazole (ESP) and lansoprazole (LP) on corrosion behavior of copper in 1 M HNO₃ solution was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The experimental results indicate that both ESP and LP inhibited the corrosion of copper in nitric acid solution and the inhibition efficiency increased as the concentration of the compounds increased. EIS measurements confirmed that the charge transfer resistance increases on increasing the inhibitor concentration. Polarization measurements showed that the inhibitors are of mixed type. From the weight loss measurements, the inhibition efficiency of the inhibitors was found to vary with concentration, immersion time, and temperature. The adsorption of inhibitors on the copper surface follows Langmuir isotherm. The surface morphology was examined by scanning electron microscope and atomic force microscope. Further, the computational calculations are performed to find a relation between their electronic and structural properties.     

Optimization of plasma treatment variables to improve the hydrophilicity of polylinen® fabrics

Polylinen^® fabrics are obtained as a result of modification in the physical structure of polyester yarns to replicate the linen fabric. The scanning electron microscope analysis and Fourier transform infrared results reveal that the plasma treated fabric surface is effectively modified to enhance the wettability of the fabrics. In the present study, response surface methodology was employed to investigate the effects of different plasma treatment variables on the wetting behavior of polylinen fabrics. Box–Behnken design was used for the optimization of plasma treatment process and to evaluate the effects and interactions of the process variables, i.e. treatment time, power, and distance between the electrodes on the wettability of polylinen fabrics. The optimum conditions for maximum wicking height (4.3?cm) and spreading rate (86?s) of polylinen fabrics were established at 75?s treatment time, 460 watt power, and 2.5?cm distance between the electrodes. The plasma treated polylinen fabrics showed much better wettability in terms of wicking and spreading rate compared to untreated fabrics, which confirms that the modified structure of polylinen fabric and the plasma treatment influences the wettability of fabrics.     

Thermal characterisation study of ZrO2/water nanofluid

ABSTRACT

Nanofluids act as tough elements in future of coolants in thermal management systems. Nanofluids have a remarkable potential in the process of heat transfer augmentation, which is reported in various investigations conducted by researchers across the world. Nanofluids attracted many researchers and the progress in this field has been tremendous because of the high thermal properties and probable applications in some areas like aerospace, transportation industry, medical regions and also as micro electronics. These fluids are having conjoined properties of base fluid and nano particles. This current work reports the thermophysical properties of ZrO₂/water-based nanofluid. The synthesised nanoparticles have been characterised by scanning electron microscope and XRD techniques. The behaviour of thermal conductivity and viscosity of the ZrO₂/water-based nanofluid of various concentrations have been studied.     

A Novel Heuristic Approach Based Trust Worthy Architecture for Wireless Sensor Networks

A Wireless Sensor Networks (WSNs) consist of spatially distributed autonomous sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants. WSNs are more vulnerable to attacks and failures due to the involvement of many numbers of tiny sensor nodes. As the technology is tremendously increasing in the recent past, the implementation of this for various time critical applications is quite interesting and challenging. Moreover, WSNs have no specific hierarchical structures, leads to security and maintenance problems. Trust in WSN is defined as the degree of belief or confidence about the nodes based on the past interactions and observations has which become a mandatory requirement for reliable communication in WSN under security constraints. In this paper, we propose a Heuristic Approach based Trust Worthy Architecture for WSN that considers the challenges of the system and focus on the collaborative mechanism for trust evaluation and maintenance. Our proposed Architecture could also be capable of fulfilling critical security, reliability, mobility and performance requirements for reliable communication while being readily adaptable to different applications. The simulation results of the proposed architecture outperformed the recent trust worthy architecture using the analysis of the performance requirements such as communication overhead, memory requirements and energy consumption.     

Face anti-spoofing by identity masking using random walk patterns and outlier detection

Pattern Analysis and Applications - Existing architectures used in face anti-spoofing tend to deploy registered spatial measurements to generate feature vectors for spoof detection. This means that...     

Fortress Abstractions in X10 Framework

International Journal of Parallel Programming - Fortress provides a nice set of abstractions used widely in scientific computing. The use of such abstractions enhances the productivity of...     

Interfacial and Bulk Magnetic Properties of Stoichiometric Cerium Doped Terbium Iron Garnet Polycrystalline Thin Films

One of the best magneto‐optical claddings for optical isolators in photonic integrated circuits is sputter deposited cerium‐doped terbium iron garnet (Ce:TbIG) which has a large Faraday rotation (≈?3500° cm^?1 at 1550 nm). Near‐ideal stoichiometry $\left(\frac{\text{Ce}+\text{Tb}}{\text{Fe}}=0.57\right)$ of Ce_0.5Tb_2.5Fe_4.75O₁₂ is found to have a 44 nm magnetic dead layer that can impede the interaction of propagating modes with garnet claddings. The effective anisotropy of Ce:TbIG on Si is also important, but calculations using bulk thermal mismatch overestimate the effective anisotropy. Here, X‐ray diffraction measurements yield highly accurate measurements of strain that show anisotropy favors an in‐plane magnetization in agreement with the positive magnetostriction of Ce:TbIG. Upon doping TbIG with Ce, a slight decrease in compensation temperature occurs which points to preferential rare‐earth occupation in dodecahedral sites and an absence of cation redistribution between different lattice sites. The high Faraday rotation, large remanent ratio, large coercivity, and preferential in‐plane magnetization enable Ce:TbIG to be an in‐plane latched garnet, immune to stray fields with magnetization collinear to direction of light propagation.