Current trends and future of sequential micro-machining processes on a single machine tool

A sequential micro-machining process chain is described as the machining strategy whereby two or more micro-machining techniques are implemented in sequence on same or different machine tools. This is in contrast to hybrid micro-machining where two standalone machining technologies are integrated together. A recent surge of interest is geared towards building sequential micro-machining capabilities on a single machine tool to avoid realignment and registration errors between processes. One of the major advantages of performing sequential micro-machining on a single machine tool is that it suppresses repositioning errors so enabling much higher levels of accuracy (and thereby tighter tolerances), reduced rejection of machined components, and lower production time; all of these would be otherwise unachievable. Thus, multifunctional micro-machining centres are attracting global interest. Clearly, the necessity of developing reconfigurable, precise and flexible manufacturing is a key driver to this trend. This review aims to provide a critical insight into the recent trends and new classification of sequential micro-machining processes with a special focus on evaluation of such capabilities built on a single machine tool and further potentials. The machining capabilities, advantages and opportunities in the area of sequential micro-machining techniques are evaluated thoroughly and the directions for future work are highlighted

Self organized criticality of magnetic avalanches in disordered ferrimagnetic material

We observe multiple step-like jumps in a Dy-Fe-Ga-based ferrimagnetic alloy in its magnetic hysteresis curve at 2 K. The observed jumps have a stochastic character with respect to their magnitude and the critical field of occurrence, and the jumps do not show any temporal effect. The jump size distribution follows a power law variation indicating the scale invariance nature of the jumps. We have invoked a simple two-dimensional random bond Ising-type spin system to model the dynamics. Our computational work can qualitatively reproduce the jumps and their scale invariant character. It also elucidates that the flipping of antiferromagnetically coupled Dy and Fe clusters is responsible for the observed discrete avalanche-like features in the hysteresis loop. These characteristics indicate that the present phenomenon can be well described within the realm of self-organized criticalityComment: 12 pages, 13 figure

Synthesis of mesogen-nanoparticle composites by doping 4-decyloxybenzoic acid with substrate-functionalized ZnO nanoparticle

Nanomaterials and Mesogenic materials are two important pillars of today’s science and technology, in the fields of both material and biological applications. Mesogens or liquid crystals (LC) are self-aggregated anisotropic fluids with long range order, and the nature of self-aggregation largely controls their physical and material properties. Doping of nanomaterials over liquid crystalline matrix can provide valuable tools for development of materials with new or improved properties. In the present work 4-decyloxybenzoic acid is taken as the mesogenic matrix. It is observed that, composite prepared by doping of 4-decyloxybenzoic acid mesogen matrix by ZnO nanoparticle pre-functionalized with the same mesogen, caused a marked alteration in the mesogenic behavior. With 3% doping of matrix pre-functionalized ZnO NP on 4- decyloxy benzoic acid, we could achieve a shift of about 31ºC in the N-Iso transition temperature and, a decrease of >10ºC for the onset of liquid crystallinity by this method without quenching any of the mesophases exhibited by the pure mesogen. The synthesized materials have been characterized by variable temperature Polarised optical microscopy (POM), DSC, FTIR, XRD, EDX, and TEM This process may be considered for preparation other nanoparticle-mesogen composites as well. It was observed that, the effect of doping on the transition temperature and enthalpy of 4-Decyloxybenzoic Acid can be significantly enhanced by pre-functionalizing the dopant (ZnO NP) with the substrate molecules and then mixing this substrate functionalized ZnO nanoparticle with the bulk substrate

Electron-phonon interaction contribution to the total energy of group IV semiconductor polymorphs: evaluation and implications

In density functional theory (DFT) based total energy studies, the van der Waals (vdW) and zero-point vibrational energy (ZPVE) correction terms are included to obtain energy differences between polymorphs. We introduce a new correction term, due to electron-phonon interactions (EPI). We rely on Allen's general formalism, which goes beyond the Quasi-Harmonic Approximation (QHA), to include the free energy contributions due to quasiparticle interactions. We show that, for semiconductors and insulators, the EPI contributions to the free energies of electrons and phonons are constant terms. Using Allen's formalism in combination with the Allen-Heine theory for EPI corrections, we calculate the zero-point EPI corrections to the total energy for cubic and hexagonal polytypes of Carbon, Silicon and Silicon Carbide. The EPI corrections alter the energy differences between polytypes. In SiC polytypes, the EPI correction term is more sensitive to crystal structure than the vdW and ZPVE terms and is thus essential in determining their energy differences. It clearly establishes that the cubic SiC-3C is metastable and hexagonal SiC-4H is the stable polytype. Our results are consistent with the experimental results of Kleykamp. Our study enables the inclusion of EPI corrections as a separate term in the free energy expression. This opens the way to beyond the QHA by including the contribution of EPI on all thermodynamic properties.Comment: Submitted for publication. 32 pages and 2 figure

Association between neutrophil to lymphocyte ratio with the severity of coronary artery diseases

Background: Coronary artery disease is a type of heart disease where the arteries of the heart cannot deliver enough oxygen-rich blood to the heart. This study aimed to evaluate the association between neutrophil to lymphocyte ratio (NLR) with the severity of coronary artery diseases. Methods: This cross-sectional study was conducted in the Department of Cardiology, Chittagong Medical College Hospital, Chattogram, Bangladesh during the period from 1 July 2020 to 31 June 2021. 160 patients undergoing elective coronary angiography with the symptoms of coronary artery disease were enrolled in this study. A purposive sampling technic was used. The association between NLR and Gensini score was assessed using Pearson’s or Spearman’s correlation analysis as appropriate. All data were processed, analyzed and disseminated by using MS Excel and SPSS version 23.0 program as per necessity. Results: The mean (±SD) Gensini score of our participants was 42.75 (±29.50) and the mean (±SD) NLR (Neutrophil-lymphocyte ratio) was 2.38 (±1.11). In this study, the AUROC for NLR was found as 0.851 with a P-value of <0.001, indicating a statistically significant association of NLR with the severity of CAD. The scatter dot diagram showed the correlation between NLR and Gensini score. Both the variables were positively correlated and the degree of correlation was found statistically significant (r=0.44; p<0.001) by Pearson’s correlation test. The multivariate logistic regression analysis showed that a high level of NLR had an independent association with severe CAD (with OR being 3.308) along with dyslipidemia. Conclusion: High blood NLR is associated with the severity of CAD and it may be useful for predicting angiographically severe disease

Investigating Project Bundling Practices for Transportation Construction Projects

Project Bundling is an innovative contract procurement strategy that is being widely used in bridge and highway projects to save project delivery time and costs. The guidebook developed by FHWA on project bundling also provides a wealth of information on project bundling. However, the guidebook is primarily focused on the project bundling practices that STAs adopted for bridge projects. Thus, a knowledge gap in project bundling for roadway projects (such as added travel lanes, resurfacing, intersection improvement, interchange work, shoulder rehabilitation and repair, etc.), might exist

The State of Applying Artificial Intelligence to Tissue Imaging for Cancer Research and Early Detection

Artificial intelligence represents a new frontier in human medicine that could save more lives and reduce the costs, thereby increasing accessibility. As a consequence, the rate of advancement of AI in cancer medical imaging and more particularly tissue pathology has exploded, opening it to ethical and technical questions that could impede its adoption into existing systems. In order to chart the path of AI in its application to cancer tissue imaging, we review current work and identify how it can improve cancer pathology diagnostics and research. In this review, we identify 5 core tasks that models are developed for, including regression, classification, segmentation, generation, and compression tasks. We address the benefits and challenges that such methods face, and how they can be adapted for use in cancer prevention and treatment. The studies looked at in this paper represent the beginning of this field and future experiments will build on the foundations that we highlight

Digital Signal Processing Research Program

Contains table of contents for Section 2, an introduction and reports on seventeen research projects.U.S. Navy - Office of Naval Research Grant N00014-91-J-1628Vertical Arrays for the Heard Island Experiment Award No. SC 48548Charles S. Draper Laboratories, Inc. Contract DL-H-418472Defense Advanced Research Projects Agency/U.S. Navy - Office of Naval Research Grant N00014-89-J-1489Rockwell Corporation Doctoral FellowshipMIT - Woods Hole Oceanographic Institution Joint ProgramDefense Advanced Research Projects Agency/U.S. Navy - Office of Naval Research Grant N00014-90-J-1109Lockheed Sanders, Inc./U.S. Navy - Office of Naval Research Contract N00014-91-C-0125U.S. Air Force - Office of Scientific Research Grant AFOSR-91-0034AT&T Laboratories Doctoral ProgramU.S. Navy - Office of Naval Research Grant N00014-91-J-1628General Electric Foundation Graduate Fellowship in Electrical EngineeringNational Science Foundation Grant MIP 87-14969National Science Foundation Graduate FellowshipCanada Natural Sciences and Engineering Research CouncilLockheed Sanders, Inc