Brake Squeal reduction through improved rotor damping

Brake Squeal Noise is a significant concern in the automotive industry and incurs enormous costs during brake system development and in brake system warranty. Several methods are utilized to minimize brake squeal, including frequency manipulation of individual brake system components through design and material modifications, active damping elements like pad shims and insulators, which typically add mass and cost to the brake system, as well as retesting costs. Brake rotors are made of grey cast iron due to their low cost, good machinability, wear and damping properties. Strength requirements limit the material damping obtainable on a consistent basis. Other methods to improve rotor damping include the use of steel inserts in the rotor plates and EDM machining of the brake rotors. Parts made with either process have been observed to reach very high levels of damping (Q factor of ~ 200) and entirely eliminate noise occurrences in the brake system.This research involves the characterization of the material and the additional processes required to achieve highly damped rotors, with a Q factor in the range of 100 to 300, which can provide significant brake noise reduction. It was discovered that electrical or magnetic processing of the rotors can create damping improvements in the range of 10 to 50 %, which are beneficial to reducing noise occurrences. EDM processing was primarily used for the study and Q factor improvements in the range of 30 to 50 % observed. Rotors with High C.E., Large Type A graphite with flake size 2 to 4, showed the largest benefits from the processing. Process DOE showed no effects of current on the damping improvements. A low processing time of 5 seconds on Non FNC rotors generated over 30 % damping improvements consistently. Noise occurrence reductions of 80 to 100 % were seen with the processed rotors. No detrimental effects were noted on other rotor performance characteristics including thermal cracking, brake torque variation, wear, and corrosion. Effects of time, temperature and wear on the damping improvements have been researched, and no significant losses were seen in typical operating conditions

Regulation of the Glutamate/glutamine Cycle by Nitric Oxide in the Central Nervous System

Nitric oxide (˙NO) is a critical contributor to glutamatergic neurotransmission in the central nervous system (CNS). Much of its influence is due to the ability of this molecule to regulate protein structure and function through its posttranslational modification of cysteine residues, a process known as S-nitrosylation. However, little is known about the extent of this modification and its associated functional effects in the brain under physiological conditions. We employed mass spectrometry (MS)-based methodologies to interrogate the S-nitrosocysteine proteome in wild-type (WT), neuronal nitric oxide synthase-deficient (nNOS-/-), and endothelial nitric oxide synthase-deficient (eNOS-/-) mouse brain. These approaches identified 269 sites from 136 proteins in the WT brain, with notable reductions in the number of sites detected in either eNOS-/- (50% of WT) or nNOS-/- brain (26% of WT). Gene ontology analysis revealed a cluster of S-nitrosylated proteins participating in the glutamate/glutamine cycle in wild-type and eNOS-/- mice that was underrepresented in nNOS-/- animals, suggesting a role for nNOS-derived ˙NO in the regulation of glutamate utilization in the CNS. Functional profiling of this pathway using 15N-glutamine based metabolomic analyses and enzymatic activity assays uncovered decreased conversion of glutamate to glutamine and increased glutamate oxidation in nNOS-/- mice relative to the other genotypes. Furthermore, site-directed mutagenesis of the rat sodium-dependent excitatory amino acid transporter 2 at Cys373 and Cys562 (Cys561 in mouse sequence), the two sites of S-nitrosylation observed in wild-type and eNOS-/- mice, revealed inhibition of glutamate transport through reversible S-nitrosylation. The selective, nNOS-dependent S-nitrosylation of proteins that govern glutamate transport and metabolism identifies a previously unknown function for ˙NO in glutamatergic neurotransmission

Does the Performance of Banking Sector Promote Economic Growth? A Time Series Analysis

Purpose: In terms of stimulating the economy, banks play an essential role. These banks directly or indirectly influence the economic growth (GDP) of a country. This study analyses the association between banks' performance and GDP growth.   Theoretical Framework: The banking sector acts as an effective mechanism that funds various projects all over the country.  The majority of such studies focus on developed nations. Although there is a great deal of literature on this issue concerning developed markets, there is a lack of literature related to emerging and developing economies (Sensarma & Bhattacharyya, 2016). This study has been undertaken to analyse the influence of banks on India's economy, which is a developing economy   Design/Methodology: The data of the study includes the independent variables that indicate banking performance. The proxies used for the bank's performance are: bank nonperforming loans to total gross loans (%) (NPL), domestic credit provided by the financial sector (% of GDP) (DC), Return on Equity (ROE), bank capital to assets ratio (%) (CAP), and regulatory capital to risk-weighted assets (CAR). At the same time, the substitute for economic growth is growth in domestic product (GDP). All organised banks operating in India form the sample of the study. The period of study is from 1990 to 2029. To test the hypotheses, simple regression, multicollinearity tests, and ordinary least square (POLS) are performed.   Findings: The findings indicate that a few of the variables such as domestic credit, return on equity, and capital adequacy ratio, which are linked to the bank's operational and financial efficiency, are correlated with India's GDP growth. The study's empirical results recommend that this country's (India's) policymakers should assist the banking sector by laying down new growth and developmental policies that will strengthen the banking sector, which will in turn strengthen the economy.   Research, Practical & Social Implications:  This study shows that Indian banks have a major impact on Indian economic growth. It also identifies the primary banking attributes that influence GDP. Such a study will help policymakers and researchers understand the significant contributors to economic growth.   Originality and Value: There are many studies that have studied the determinants of GDP. But this is the first study that has tried to establish the impact/relationship of banking variables on GDP growth

Experimental and numerical studies on the damage behavior of open hole CFRP composite specimen subjected to compression

In this work, the progressive failure of open hole composite specimen subjected to compression is studied. CFRP laminates of various stacking sequence (unidirectional, cross-ply, quasi-isotropic) with a circular hole are fabricated and tested under compressive loading. An anti-buckling compression fixture is used to prevent buckling of specimens. In this work, a unified experimental approach comprising of digital image correlation (DIC), acoustic emission (AE) and strain gauge are used to study the damage mechanisms of open hole CFRP specimen under compression. DIC is employed to capture the surface strain field near the hole of the CFRP specimen. AE is used to study the initiation and progression of various damage modes in the CFRP specimen. AE parameters are then used to classify the various damage events in uni-directional, cross-ply and quasi-isotropic laminates. Strain gauges are also employed to capture the failure strain information close to the hole. Subsequently, fractography studies are carried out to ascertain the occurrence of various damage modes in the specimen. In additon, finite element (FE) simulation of the progressive damage failure of the open hole CFRP specimen is done using ABAQUS software. Three-dimensional brick elements (C3D8R) are used to simulate the compression failure in the CFRP specimen. A VUMAT subroutine is coded to study the matrix compression and fiber kink failure based on Pinho’s damage model. Numerical results obtained from FE simulations are then compared with experimental observations, and the accuracy of the FE model is validated

The National COVID Cohort Collaborative (N3C): Rationale, design, infrastructure, and deployment.

OBJECTIVE: Coronavirus disease 2019 (COVID-19) poses societal challenges that require expeditious data and knowledge sharing. Though organizational clinical data are abundant, these are largely inaccessible to outside researchers. Statistical, machine learning, and causal analyses are most successful with large-scale data beyond what is available in any given organization. Here, we introduce the National COVID Cohort Collaborative (N3C), an open science community focused on analyzing patient-level data from many centers. MATERIALS AND METHODS: The Clinical and Translational Science Award Program and scientific community created N3C to overcome technical, regulatory, policy, and governance barriers to sharing and harmonizing individual-level clinical data. We developed solutions to extract, aggregate, and harmonize data across organizations and data models, and created a secure data enclave to enable efficient, transparent, and reproducible collaborative analytics. RESULTS: Organized in inclusive workstreams, we created legal agreements and governance for organizations and researchers; data extraction scripts to identify and ingest positive, negative, and possible COVID-19 cases; a data quality assurance and harmonization pipeline to create a single harmonized dataset; population of the secure data enclave with data, machine learning, and statistical analytics tools; dissemination mechanisms; and a synthetic data pilot to democratize data access. CONCLUSIONS: The N3C has demonstrated that a multisite collaborative learning health network can overcome barriers to rapidly build a scalable infrastructure incorporating multiorganizational clinical data for COVID-19 analytics. We expect this effort to save lives by enabling rapid collaboration among clinicians, researchers, and data scientists to identify treatments and specialized care and thereby reduce the immediate and long-term impacts of COVID-19

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion

Abstract: The B.1.617.2 (Delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha)1. In vitro, B.1.617.2 is sixfold less sensitive to serum neutralizing antibodies from recovered individuals, and eightfold less sensitive to vaccine-elicited antibodies, compared with wild-type Wuhan-1 bearing D614G. Serum neutralizing titres against B.1.617.2 were lower in ChAdOx1 vaccinees than in BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies to the receptor-binding domain and the amino-terminal domain. B.1.617.2 demonstrated higher replication efficiency than B.1.1.7 in both airway organoid and human airway epithelial systems, associated with B.1.617.2 spike being in a predominantly cleaved state compared with B.1.1.7 spike. The B.1.617.2 spike protein was able to mediate highly efficient syncytium formation that was less sensitive to inhibition by neutralizing antibody, compared with that of wild-type spike. We also observed that B.1.617.2 had higher replication and spike-mediated entry than B.1.617.1, potentially explaining the B.1.617.2 dominance. In an analysis of more than 130 SARS-CoV-2-infected health care workers across three centres in India during a period of mixed lineage circulation, we observed reduced ChAdOx1 vaccine effectiveness against B.1.617.2 relative to non-B.1.617.2, with the caveat of possible residual confounding. Compromised vaccine efficacy against the highly fit and immune-evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era

Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial

Background: Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients. Methods: We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open major abdominal surgery. Eligible UK National Health Service (NHS) hospitals (those that had an emergency general surgical service, a substantial volume of emergency abdominal surgery cases, and contributed data to the National Emergency Laparotomy Audit) were organised into 15 geographical clusters and commenced the QI programme in a random order, based on a computer-generated random sequence, over an 85-week period with one geographical cluster commencing the intervention every 5 weeks from the second to the 16th time period. Patients were masked to the study group, but it was not possible to mask hospital staff or investigators. The primary outcome measure was mortality within 90 days of surgery. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN80682973. Findings: Treatment took place between March 3, 2014, and Oct 19, 2015. 22 754 patients were assessed for elegibility. Of 15 873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 patients in the usual care group and 7374 in the QI group. Eight patients in the usual care group and nine patients in the QI group were not included in the analysis because of missing primary outcome data. The primary outcome of 90-day mortality occurred in 1210 (16%) patients in the QI group compared with 1393 (16%) patients in the usual care group (HR 1·11, 0·96–1·28). Interpretation: No survival benefit was observed from this QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. Future QI programmes should ensure that teams have both the time and resources needed to improve patient care. Funding: National Institute for Health Research Health Services and Delivery Research Programme

Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial

BACKGROUND: Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients. METHODS: We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open major abdominal surgery. Eligible UK National Health Service (NHS) hospitals (those that had an emergency general surgical service, a substantial volume of emergency abdominal surgery cases, and contributed data to the National Emergency Laparotomy Audit) were organised into 15 geographical clusters and commenced the QI programme in a random order, based on a computer-generated random sequence, over an 85-week period with one geographical cluster commencing the intervention every 5 weeks from the second to the 16th time period. Patients were masked to the study group, but it was not possible to mask hospital staff or investigators. The primary outcome measure was mortality within 90 days of surgery. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN80682973. FINDINGS: Treatment took place between March 3, 2014, and Oct 19, 2015. 22 754 patients were assessed for elegibility. Of 15 873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 patients in the usual care group and 7374 in the QI group. Eight patients in the usual care group and nine patients in the QI group were not included in the analysis because of missing primary outcome data. The primary outcome of 90-day mortality occurred in 1210 (16%) patients in the QI group compared with 1393 (16%) patients in the usual care group (HR 1·11, 0·96-1·28). INTERPRETATION: No survival benefit was observed from this QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. Future QI programmes should ensure that teams have both the time and resources needed to improve patient care. FUNDING: National Institute for Health Research Health Services and Delivery Research Programme

Finite element analysis of load sharing in a hybrid bonded/bolted joint using an interference-fit bolt

Efficient joint designs are key to exploit the full potential of composite materials, which are being increasingly used in aircraft structures. Composite structures are traditionally joined by either mechanical fastening or adhesive bonding. Recently there has been a renewed interest in combining both these joining techniques despite the different stiffness of the load paths offered by the adhesive bond and the bolts. Certain designs have shown hybrid bonded/bolted (HBB) joints to possess higher static and fatigue strength compared to the individual underlying joints separately. This improvement in the joint behavior has been attributed to the substantial load sharing between the adhesive and the bolt. However, in these designs, despite using a low modulus adhesive, the bolt does not participate initially in sharing the load until the adhesive has completely yielded. Consequently, there is a need to improve this load sharing behavior in a HBB joint, wherein the bolt can start sharing the load with the adhesive as soon as the joint is loaded. In this study, a new design for the hybrid joint with an interference-fit bolt was conceived and investigated using a three-dimensional finite element model. This design facilitated improved load sharing between the bolt and adhesive. An interference-fit bolt HBB joint further offers potential to improve the joint behavior by limiting the plastic strains around the bolt-hole, increasing load transfer through friction and improving electrical conductivity in the laminates for lightening protection in aircraft structures.La conception des jonctions efficaces est la clé pour exploiter tout le potentiel des matériaux composites, qui sont de plus en plus utilisés dans les structures d'aéronefs. Les structures composites sont habituellement assemblées soit par fixation mécanique ou collage. Récemment il y a eu un regain d'intérêt à combiner ces deux techniques d'assemblage, malgré la différence de rigidité des différents chemins de charge offertes par la liaison adhésive et les boulons. Certaines expériences ont montré que les jonctions hybrides boulonnés/collés (HBC) possèdent une plus grande résistance statique ainsi qu'une durée de vie plus longue par rapport aux jonctions. Cette amélioration du comportement de la jonction a été attribuée à une répartition importante de charge entre l'adhésif et le boulon. Cependant, dans ces conceptions, malgré l'utilisation d'un adhésif à faible module, le boulon ne participe initialement pas à partager la charge, jusqu'à ce que la colle dépasse la limite d'élasticité. Par conséquent, il est nécessaire d'améliorer le comportement de répartition de charge dans une jonction HBC, puisque le boulon peut commencer à partager la charge avec l'adhésif dès que la jonction est chargée. Dans cette étude, une nouvelle conception d'une jonction hybride avec un boulon d'ajustement serré a été développée et étudiée en utilisant un modèle éléments finis à trois dimensions. Cette conception facilite une meilleure répartition de charge entre le boulon et l'adhésif. Une jonction HBC avec boulon d'ajustement serré offre encore un potentiel pour améliorer le comportement de la jonction en limitant les déformations plastiques autour du trou de boulon, augmente le transfert de charge par frottement et en améliore la conductivité électrique dans les stratifiés pour protéger contre la foudre dans les structures d'aéronefs