Microstructure and Wear of Cathodic Arc Physical Vapour Deposited on TiAlN, TiCrN and n TiAlN Alpha Si3N4 Films

Present study examined the microstructural features, hardness and wear performance of TiAlN, TiCrN and            n-TiAlN/α-Si3N4 coatings deposited by cathodic arc physical vapour deposition (CA-PVD) technique on M-50 steel keeping in mind a possible application of hybrid bearings in next generation aero-engine. Microstructural features of the coatings were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy. Hardness was measured using microhardness tester. Wear test was carried out with the help of ‘Bruker’ tribometer. Worn surfaces were characterised employing SEM. Results show that TiCrN coating has crystalline columnar structure and other coatings have nano-crystalline structures. Besides improved hardness, TiAlN has best wear resistance and TiCrN coating exhibits least friction coefficient

Total arterial anaortic off-pump coronary artery bypass grafting in a patient with heart failure – Case report

AbstractA 69-year-old male diabetic patient of heart failure underwent successful off-pump coronary artery bypass grafting (CABG) using both internal thoracic arteries and left radial artery. There was improvement of left ventricular ejection fraction within 4 days. This is the first ever case report of off-pump CABG in a heart failure patient

Real Time Vehicle Identification: A Synchronous-Transmission Based Approach

Identification of the vehicles passing over the roads is a very important component of traffic monitoring/surveillance. There have been many attempts to design and develop efficient strategies to carry out the job. However, from the point of view of practical usefulness and real-time operation, most of them do not score well. In the current work, we perceive the problem as efficient real-time communication and data-sharing between the units in charge of recording the identities of the vehicles, i.e., Vehicle Recorders (VR), and the Vehicles (VE). We propose a strategy to address the issue with the help of Synchronous-Transmission (ST), which is a newer paradigm of communication compared to the traditional paradigm based on Asynchronous-Transmission (AT). First, we theoretically show that the presence of the physical layer phenomena called Capture-Effect in ST brings a significant benefit. Next, we also implement the strategy in a well-known IoT-Operating System Contiki, and compare its performance with the existing best-known strategy

A first principles investigation of cubic BaRuO3_3: A Hund's metal

A first-principles investigation of cubic-BaRuO$_3$, by combining density functional theory with dynamical mean-field theory and a hybridization expansion continuous time quantum Monte-Carlo solver, has been carried out. Non-magnetic calculations with appropriately chosen on-site Coulomb repulsion, $U$ and Hund's exchange, $J$, for single-particle dynamics and static susceptibility show that cubic-BaRuO$_3$ is in a spin-frozen state at temperatures above the ferromagnetic transition point. A strong red shift with increasing $J$ of the peak in the real frequency dynamical susceptibility indicates a dramatic suppression of the Fermi liquid coherence scale as compared to the bare parameters in cubic-BaRuO$_3$. The self-energy also shows clear deviation from Fermi liquid behaviour that manifests in the single-particle spectrum. Such a clean separation of energy scales in this system provides scope for an incoherent spin-frozen (SF) phase, that extends over a wide temperature range, to manifest in non-Fermi liquid behaviour and to be the precursor for the magnetically ordered ground state.Comment: 10 pages, 12 figures, 1 tabl

Evaluation of speed–flow characteristics on two-lane highways with mixed traffic

The HCM (Highway Capacity Manual 2010) classifies two-lane rural highway that passes through developed areas as ‘Class III’ and suggests using Percent Free-Flow Speed (PFFS) as performance measure to define Level Of Service (LOS). Apparently, this performance measure addresses the main limitation associated with using Average Travel Speed (ATS) as a measure of performance. However, larger speed differential under heterogeneous traffic causes error in estimating Free-Flow Speed (FFS) and thus affects PFFS. This implication was examined in the present study using field data collected on a national highway approaching a city. Speed–flow equations were developed and intercept values were compared to the FFS obtained according to HCM guidelines. Comparison confirms a very close agreement between average FFS value and those obtained for different types of vehicle separately except for car. This consequently causes an error in estimating PFFS since the traffic composition consists of significant proportion of car. The possible capacity of the highway section was observed to be around 2300 pc/h for mixed traffic situation. First published online: 28 Jan 201

Pre-exposure hydroxychloroquine prophylaxis for COVID-19 in healthcare workers: a retrospective cohort

Background: While several trials are ongoing for treatment of Corona virus 2019 (COVID-19), scientific research on chemoprophylaxis is still lacking even though it has potential to flatten the curve allowing us time to complete research on vaccines.Methods: This retrospective cohort study explores the potential of hydroxychloroquine (HCQ) as a pre- exposure prophylaxis for COVID-19 among 106 health care workers (HCW) exposed to COVID-19 patients, at a tertiary care hospital in India where there was an abrupt cluster outbreak within on duty personnel. HCWs who had voluntarily taken HCQ prior to exposure were considered one cohort while those who had not were considered to be the Control group. All participants with a verifiable high-risk contact history were tested for COVID-19 by RT- PCR.Results: The two cohorts were comparable in terms of age, gender, co-morbidity and exposure. The primary outcome was incidence rates of RT-PCR positive COVID-19 infection among HCQ users and Controls.106 HCW were examined of whom 54 were HCQ users. The comparative analysis of incidence of infection between the two groups demonstrated that voluntary HCQ usage was associated with lesser likelihood of developing severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection (4 out of 54 HCW), compared to those who were not on it (20 out of 52 HCW), χ2=14.59, p<0.001. None of the HCQ users noted any serious adverse effects.Conclusions: The study demonstrated that voluntary pre- exposure HCQ prophylaxis by HCWs is associated with a statistically significant reduction in risk of SARS-CoV-2.

Recent Progress of Electrocatalysts and Photocatalysts Bearing First Row Transition Metal for Hydrogen Evolution Reaction (HER)

The design and modification of metal–organic complexes for hydrogen (H2) gas production by water splitting have been intensively investigated over the recent decades. In most reported mechanistic pathways, metal hydride species are considered as crucial intermediates for H2 formation where the metal present at the active site plays an imperative role in the transfer of electron and proton. In the last few decades, much consideration has been done on the development of non-precious metal–organic catalysts that use solar energy to split water into hydrogen (H2) and oxygen (O2) as alternative fossil fuels. This review discussed the design, fabrication, and evaluation of the catalysts for electrocatalytic and photocatalytic hydrogen production. Mechanistic approach is addressed here in order to understand the fundamental design principle and structural properties relationship of electrocatalysts and photocatalysts. Finally, we discuss some challenges and opportunities of research in the near future in this promising area