Development of 2024 p/m aluminium alloy–SiCp nanocomposites via mechanical alloying

Aluminum alloy 2024 is the best known most widely used aircraft structural alloy. Now a days it is also gaining ground in automotive industry. In the present studies, 2024 P/M Al alloy and SiC particulates have been chosen as matrix and reinforcement materials, respectively. Mechanical alloying (MA) was used to obtain uniform SiCp dispersion in the matrix. MA powder was vacuum degassed and consolidated by hot pressing and subsequent hot forging. Thereafter the composites were heat treated to give T-6 temper. Optical and scanning electron microscopy of the composite was carried out and evaluation of mechanical properties was done. The principal objective of the present investigations was to determine how the particulate volume fraction and extent of mechanical alloying affect the microstructure and tensile properties of 2024 P/M Al alloy-SiCp composites. In these efforts it could be possible to develop nano composites of 2024 P/M Al alloy-SiCp having tensile strength of 504 MPa and modulus of elasticity of 105 GPa

Depletion of M. tuberculosis GlmU from infected murine lungs effects the clearance of the pathogen

M. tuberculosis N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmUMtb) is a bi-functional enzyme engaged in the synthesis of two metabolic intermediates N-acetylglucosamine-1-phosphate (GlcNAc-1-P) and UDP-GlcNAc, catalyzed by the C- and N-terminal domains respectively. UDP-GlcNAc is a key metabolite essential for the synthesis of peptidoglycan, disaccharide linker, arabinogalactan and mycothiols. While GlmUMtb was predicted to be an essential gene, till date the role of GlmUMtb in modulating the in vitro growth of Mtb or its role in survival of pathogen ex vivo / in vivo have not been deciphered. Here we present the results of a comprehensive study dissecting the role of GlmUMtb in arbitrating the survival of the pathogen both in vitro and in vivo. We find that absence of GlmUMtb leads to extensive perturbation of bacterial morphology and substantial reduction in cell wall thickness under normoxic as well as hypoxic conditions. Complementation studies show that the acetyl- and uridyl- transferase activities of GlmUMtb are independently essential for bacterial survival in vitro and GlmUMtb is also found to be essential for mycobacterial survival in THP-1 cells as well as in guinea pigs. Depletion of GlmUMtb from infected murine lungs, four weeks post infection, led to significant reduction in the bacillary load. The administration of Oxa33, a novel oxazolidine derivative that specifically inhibits GlmUMtb, to infected mice resulted in significant decrease in the bacillary load. Thus our study establishes GlmUMtb as a strong candidate for intervention measures against established tuberculosis infections

Event-triggered control for LPV modeling of DC-DC boost converter

This study presents the event-triggered control (ETC) for linear parameter varying (LPV) model of boost converters. We examine the nonlinear dynamics of boost converters in the LPV framework. The proposed controller is duty-ratio-dependent and provides better performance while requiring less computation. Using the parameter-dependent Lyapunov function (PDLF), we demonstrate the stablity analysis of the proposed approach. Furthermore, we demonstrate that the inter-event time is lower bound by a positive constant, which indicates Zeno behavior free performance. In comparison to earlier time-invariant synthesis techniques, the LPV formulation offers for increased robustness and performance properties. Simulation and experimental results validate the effectiveness of the proposed method

Serological and molecular prevalence of Brucella spp. among livestock species in Rajasthan, India

A seroprevalence and molecular study was carried out in six districts of the state of Rajasthan, India to detect brucellosis in major livestock species. This study involves the testing of 3,245 livestock samples using the Rose Bengal Plate Test (RBPT), Indirect Enzyme-Linked Immunosorbent Assay (i-ELISA), and genus-specific polymerase chain reaction (PCR) markers for molecular diagnosis of the disease. In the tested samples, seroprevalence was 5.06% (CI: 1.96–8.15) using the RBPT test and 6.88% (CI: 1.98–11.78) using the i-ELISA test, while the cumulative seroprevalence (RBPT and i-ELISA) was 3.63% (CI: 0.44–6.83). The prevalence of the disease was 1.27% (CI: 0.56–3.11) when tested using molecular markers. The highest prevalence of brucellosis was detected in Cattle (7.00, 3.22%), followed by camels (5.50, 2.50%), buffalo (2.66, 0.00%), sheep (2.43, 0.41%), and goats (0.58, 0.23%) when serological (cumulative) and molecular diagnosis were considered preferred methods of detection. Cattle (3.22%) and camels (2.50%) also showed a high prevalence of disease when tested using molecular markers. The results of this study reveal that cattle, camel, and sheep brucellosis is prevalent in the study areas

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

Classification of classical Friedrichs differential operators: One-dimensional scalar case

The theory of abstract Friedrichs operators, introduced by Ern, Guermond and Caplain (2007), proved to be a successful setting for studying positive symmetric systems of first order partial differential equations (Friedrichs, 1958), nowadays better known as Friedrichs systems. Recently, Antoni\'c, Michelangeli and Erceg (2017) presented a purely operator-theoretic description of abstract Friedrichs operators, allowing for application of the universal operator extension theory (Grubb, 1968). In this paper we make a further theoretical step by developing a decomposition of the graph space (maximal domain) as a direct sum of the minimal domain and the kernels of corresponding adjoints. We then study one-dimensional scalar (classical) Friedrichs operators with variable coefficients and present a complete classification of admissible boundary conditions.Comment: 28 pages, 3 figure

Physical and psychological health problems associated with tobacco consumption among professional drivers in India

Background Tobacco use is a global health issue and a leading preventable cause of morbidity and mortality. More than 25 diseases are known or strongly suspected because of tobacco use. Individuals with lower level of education and low socio economic status are found to have higher consumption of tobacco as compared to other job titles. Therefore the present study was planned to assess tobacco related physical and psychological health problems of professional drivers. Methods A descriptive research design was used to collect the data. A total of 521 professional drivers were contacted in Ludhiana district of India, of which 331 agreed to participate. Besides socio demographic profile, the data pertaining to duration of driving, history of illness, age of starting tobacco, duration of tobacco regularly used, form of tobacco, tobacco dependence, etc. were collected. The information was collected on structured questionnaire and Kessler scale was used to assess the psychological distress. The data was statistically analyzed by using SPSS 20.0 version. Results Out of 331 professional drivers, 201( 60.7%) were regularly consuming tobacco. 41.5% were in the age of 31-40 years; 51.5% educated upto secondary level; 81.5% married and 60.5% residing in urban area. Majority (79.8%) of subjects who consume tobacco reported various types of physical health problems - 25.8% had respiratory; 33.7% cardiovascular; 23.0% gastrointestinal and 8.5% urinary problems. Only 0.66% reported lung cancer. 36.5% had medium while 63.5% low psychological distress. There was significant positive correlation (p=0.001) between level of dependence and psychological distress. Almost half (49.5%) of the drivers wanted to quit while the other half refused to quit due to various reasons like taking tobacco is not harmful (27.5%); impossible to quit (16%) and to remain active (6.5%). Conclusions Professional drivers consuming tobacco are found to suffer from various physical and psychological health problems. Their health need to be assessed regularly for improving their quality of life

Multi-bit MRAM based high performance neuromorphic accelerator for image classification

Binary neural networks (BNNs) are the most efficient solution to bridge the design gap of the hardware implementation of neural networks in a resource-constrained environment. Spintronics is a prominent technology among emerging fields for next-generation on-chip non-volatile memory. Spin transfer torque (STT) and spin-orbit torque (SOT) based magnetic random-access memory (MRAM) offer non-volatility and negligible static power. Over the last few years, STT and SOT-based multilevel spintronic memories have emerged as a promising solution to attain high storage density. This paper presents the operation principle and performance evaluation of spintronics-based single-bit STT and SOT MRAM, dual-level cells, three-level cells (TLCs), and four-level cells. Further, multi-layer perceptron architectures have been utilized to perform MNIST image classification with these multilevel devices. The performance of the complete system level consisting of crossbar arrays with various MRAM bit cells in terms of area, energy, and latency is evaluated. The throughput efficiency of the BNN accelerator using TLCs is 26.6X, and 3.61X higher than conventional single-bit STT-MRAM, and SOT-MRAM respectively