High speed continuous and interrupted dry turning of A390 Aluminum/Silicon Alloy using nanostructured diamond coated WC–6 wt.% cobalt tool inserts by MPCVD

Nanostructured diamond films were grown to a thickness of approximately 35 µm by a 30 kW, 915 MHz, microwave plasma-assisted chemical vapor deposition (MPCVD) on chemically treated WC–6 wt.% Co tool inserts. Rockwell indentation tests were performed to evaluate the adhesion of the films and compared to that of traditional microcrystalline diamond. A series of high speed dry turning tests on high-silicon (18 wt.% Si) aluminum alloy A390 under continuous and interrupted modes were performed and comparisons were carried out to investigate the wear behavior on tool inserts that were uncoated, coated with nanostructured diamond, and commercial PCD (polycrystalline diamond cutter) ones. The tests showed that nanostructured diamond coatings demonstrated excellent durability against the highly abrasive A390 aluminum–silicon alloys in high speed dry turning. Ultra fine grain structure of this coating produces workpiece surface finish comparable or even better than PCD tools in the range we studied. Excellent coating adhesion of nanostructured diamond on WC–6% Co substrates leads to reliable wear behavior. For the first time, we evaluated the performance of nanostructured diamond film coated insert under high speed interrupted turning mode. A “self-cleaning” mechanism was observed which can significantly improve the performance of nanostructured diamond films. Micro-Raman spectra were taken on tested tools to study the wear mechanism of the coating.     

Loop‐Mediated Isothermal Amplification (LAMP): A Rapid and Sensitive Tool for Quality Assessment of Meat Products

Loop‐mediated isothermal amplification (LAMP) is a novel method that amplifies target nucleic acids under isothermal conditions. It is a rapid, specific, and sensitive method, which does not require costly thermal cyclers for the detection of nucleic acids. Thus, it is suitable for on‐site detection assays under low‐resource settings. It can also be integrated on compact lab‐on‐a‐chip devices for the development of micro‐total analysis systems. This review discusses LAMP‐based methods, as well as LAMP‐based centrifugal, microfluidic, and other fluid‐handling devices, which have been developed for the assessment of meat quality parameters that are related to the presence or absence of nucleic acids, for example, animal species identification and microbiological quality. Advances in improving the rapidity, specificity, and sensitivity of LAMP techniques for the assessment of these meat quality parameters are also discussed in this review.     

Nanoscale Ⅲ-V on Si-based junctionless tunnel transistor for EHF band applications

A single gate Ⅲ-V junctionless tunnel field effect transistor (SG-JLTFET) has been reported which shows excellent dc characteristics at low power supply operation. This device has a thin uniformly n-type doped channel of GaSb i.e. gallium antimonide which is grown epitaxially over silicon substrate. The DC performance parameters such as I_ON, I_ON/I_OFF, average and point subthreshold slope as well as device parameters for analog applications viz. transconductance g_m, transconductance generation efficiency g_m/I_D, various capacitances and the unity gain frequency f_T are studied using a device simulator. Along with examining its endurance to short channel effects, the performances are also compared with a Silicon Dual Gate Junctionless Tunnel FET (DG-JLTFET). The DC and small signal analog performance reflects that GaSb SG-JLTFET has immense purview for extreme high-frequency and low-power applications.     

EFFECT OF DRAW FURNACE GEOMETRY ON HIGH-SPEED OPTICAL FIBER MANUFACTURING

Optimal design of the draw furnace is particularly desirable to meet the need of high-volume production in the optical fiber industry. This article investigates the thermal transport and flow in optical fiber drawing at high draw speeds in a cylindrincal graphite furnace. A conjugate problem involving the glass and the purge gases is solved. The transport in the two regions is coupled through the boundary conditions at the free glass surface. The neck-down profile of the preform at steady state is determined by a force balance, using an iterative numerical scheme. To emphasize the effects of draw furnace geometry, the diameters of the preform and the fiber are kept fixed. Only the length and the diameter of the furnace are changed. For the purposes of comparison, a wide domain of draw speeds, ranging from 5 m/s to 20 m/s, is considered, and the form of the temperature distribution at the furnace surface remains unchanged. The dependence of the preform/fiber characteristics on the furnace geometry are demonstrated quantitively. Based on these numerical results, an optimal design of the draw furnace can be developed.     

A combined experimental‐numerical framework for residual energy determination in spent lithium‐ion battery packs

The present research proposes a combined framework that evaluates remaining capacity, material behavior, ions concentration of remaining metals, and current rate of chemical reactions of spent Li‐ion batteries accurately. Voltage, temperature, internal resistance, and capacity were studied during charging and discharging cycles. Genetic programming was applied on the obtained data to develop a model to predict remaining capacity. The results of experimental work and those estimated from model were found to be correlated, confirming the validation of model. Materials structure and electrochemical behavior of electrodes during cycles were studied by cyclic voltammetry, scanning electron microscopy, and energy dispersion spectrum.     

Convective heat transfer in pressure-driven nitrogen slip flows in long microchannels: The effects of pressure work and viscous dissipation

An analytical and numerical study is carried out to examine the convective heat transfer in two-dimensional pressure-driven nitrogen slip flows in long microchannels, whose length-to-height ratios are above 500. The momentum and the energy equations are solved, where variable properties, rarefaction that involves velocity slip, thermal creep and temperature jump, pressure work, and viscous dissipation are all taken into account. Nitrogen is assumed to be a perfect gas. The effects of pressure work and viscous dissipation, which are particularly significant for long microchannels, are examined by analyzing the uniform wall temperature and the uniform wall heat flux cases. It is found that the degree of rarefaction, which is characterized by the Knudsen number, is the key factor that determines the relative importance of pressure work and viscous dissipation. It is demonstrated that, for perfect gases, rarefaction promotes the conversion of internal energy to mechanical energy. Specifically, regardless of the fluid field development, pressure work and viscous dissipation cancel out in the absence of rarefaction, while pressure work is greater than viscous dissipation with rarefaction and its dominance increases as the Knudsen number increases. It is shown that the combination of pressure work and viscous dissipation makes a significant impact on the Nusselt number in both the continuum and the rarefaction cases. Therefore, it is concluded that for convective heat transfer in internal gas flows, both pressure work and viscous dissipation need to be considered in analysis.     

Improving reliability and reducing cost of task execution on preemptible VM instances using machine learning approach

The Journal of Supercomputing - Cloud users can acquire resources in the form of virtual machines (VMs) instances for computing. These instances can be on-demand, reserved and spot instances....     

Facile and green synthesis of highly dispersed cobalt oxide (Co3O4) nano powder: Characterization and screening of its eco-toxicity

A novel green synthesis of cobalt oxide (Co₃O₄) nanoparticles using latex of Calotropis procera via simple precipitation method at room temperature was investigated. An extensive characterization of the product was carried out using X-ray diffractometry (XRD), Differential scanning calorimetry (DSC), Transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) and UV–Visible spectroscopy. The results of the characterization confirmed that the synthesized nanomaterial is highly dispersed. TEM analysis revealed that the nano particles are having an average size around 10?nm. The eco-toxic investigation suggested that the particles are non-toxic and safe towards the environment. This green strategy proves to be an effective, fast, simple and cost-effective approach for the synthesis of Co₃O₄ nanoparticles for various applications.     

Growth and characterization of Ni substituted Bi2Se3 single crystals

Journal of Superconductivity and Novel Magnetism - In this article, we report synthesis and magneto-transport analysis of Ni substituted Bi2Se3 crystals. Phase purity and crystalline growth are...     

Blind Signal Modulation Recognition through Density Spread of Constellation Signature

Wireless Personal Communications - Cluster analysis is a commonly used technique by investors to create a diversified portfolio. The approach aims at maximizing returns for a tolerable degree of...