95 research outputs found

    Unsteady MHD Radiative and Chemically Reactive Free Convection Flow near a Moving Vertical Plate in Porous Medium

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    We have investigated an unsteady flow of a viscous, incompressible electrically conducting, laminar free convection boundary layer flow of a moving infinite vertical plate in a radiative and chemically reactive medium in the presence of a transverse magnetic field. The equations governing the flow are solved by Laplace transform technique. The expressions for velocity, temperature, concentration are derived and based on these quantities the expressions for skin friction; rate of heat transfer and the rate mass transfer near the plate are derived. The effects of various physical parameters on flow quantities, wise magnetic parameter, Grashof number, modified Grashof number, heat source parameter, the chemical reaction parameter, Schmidt number and radiation parameter are studied numerically and the results are discussed with the help of graphs. Some important applications of physical interest for different type motion of the plate like case (i) when the plate is moving with uniform velocity, case (ii) when the plate is moving with single acceleration and case (iii) when the plate is moving with periodic acceleration, are discussed

    Effects of Thermal Diffusion and Radiation on Magnetohydrodynamic (MHD) Chemically Reacting Fluid Flow Past a Vertical Plate in a Slip Flow Regime

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    An analysis has been conceded to study the effects of Soret and thermal radiation effects on the magnetohydrodynamic convective flow of a viscous, incompressible, electrically conducting fluid with heat and mass transfer over a plate with time-dependent suction velocity in a slip flow regime in the presence of first-order chemical reaction. The slip conditions at the boundaries for the governing flow are taken for the velocity and temperature distributions and a uniform magnetic field of strength is applied normal to the flow direction. The free stream velocity is assumed to be subject to follow an exponentially small perturbation law. Analytical solutions are obtained for velocity, temperature and concentration fields for the governing partial differential equations depending on slip flow boundary circumstances by using the traditional perturbation method

    Influence of cathode calendering density on the cycling stability of Li-Ion batteries using NMC811 single or poly crystalline particles

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    Calendering of battery electrodes is a commonly used manufacturing process that enhances electrode packing density and therefore improves the volumetric energy density. While calendering is standard industrial practice, it is known to crack cathode particles, thereby increasing the electrode surface area. The latter is particularly problematic for new Ni-rich layered transition metal oxide cathodes, such as NMC811, which are known to have substantial surface-driven degradation processes. To establish appropriate calendering practices for these new cathode materials, we conducted a comparative analysis of uncalendered electrodes with electrodes that have a 35% porosity (industrial standard), and 25% porosity (highly calendered) for both single crystal (SC) and polycrystalline (PC) NMC811. PC cathodes show clear signs of cracking and decrease in rate capability when calendered to 25% porosity, whereas SC NMC811 cathodes, achieve better cycling stability and no penalty in rate performance at these high packing densities. These findings suggest that SC NMC811 cathodes should be calendered more densely, and we provide a comprehensive overview of both electrochemical and material characterisation methods that corroborate why PC and SC electrodes show such different degradation behaviour. Overall, this work is important because it shows how new single-crystal cathode materials can offer additional advantages both in terms of rate performance and cycling stability by calendaring them more densely

    Review of experimental methods to determine spontaneous combustion susceptibility of coal – Indian context

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    This paper presents a critical review of the different techniques developed to investigate the susceptibility of coal to spontaneous combustion and fire. These methods may be sub-classified into the two following areas: (1) Basic coal characterisation studies (chemical constituents) and their influence on spontaneous combustion susceptibility. (2) Test methods to assess the susceptibility of a coal sample to spontaneous combustion. This is followed by a critical literature review that summarises previous research with special emphasis given to Indian coals

    Formulation, characterization and in vivo evaluation of novel edible dosage form containing nebivolol HCl

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    ABSTRACT The objective of this investigation was to develop a novel oral edible gel dosage form for nebivolol hydrochloride, with suitable rheological characteristics that can provide a means of administering the drug to dysphagic and geriatric patients. Edible gels were prepared using low acetylated gellan gum and sodium citrate in different concentrations. The effect of concentration of the solution on gelation time, viscosity, and drug release was studied. Optimized formulation had "spoon thick" consistency that is considered suitable for dysphagic patients as suggested by National Dysphagia Diet Task Force. The optimized formulation containing gellan gum (0.4 % w/v) and sodium citrate (0.3 % w/v) showed more than 95% drug release in 20 minutes. This formulation also showed significantly better pharmacokinetic profile when compared to marketed conventional tablets in New Zealand white rabbits (n = 3). Optimized formulation was found stable for 6 months when stored at 25 °C ± 0.2 °C/60 ± 5% RH. From this study, it can be concluded that the novel edible gel dosage form containing nebivolol hydrochloride may prove to be more efficacious in the treatment of hypertension in dysphagic patients

    Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: A systematic analysis for the Global Burden of Disease Study 2015

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    Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods: We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings: Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation: Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding: Bill & Melinda Gates Foundation

    Effects of rare kidney diseases on kidney failure: a longitudinal analysis of the UK National Registry of Rare Kidney Diseases (RaDaR) cohort

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    Background Individuals with rare kidney diseases account for 5–10% of people with chronic kidney disease, but constitute more than 25% of patients receiving kidney replacement therapy. The National Registry of Rare Kidney Diseases (RaDaR) gathers longitudinal data from patients with these conditions, which we used to study disease progression and outcomes of death and kidney failure. Methods People aged 0–96 years living with 28 types of rare kidney diseases were recruited from 108 UK renal care facilities. The primary outcomes were cumulative incidence of mortality and kidney failure in individuals with rare kidney diseases, which were calculated and compared with that of unselected patients with chronic kidney disease. Cumulative incidence and Kaplan–Meier survival estimates were calculated for the following outcomes: median age at kidney failure; median age at death; time from start of dialysis to death; and time from diagnosis to estimated glomerular filtration rate (eGFR) thresholds, allowing calculation of time from last eGFR of 75 mL/min per 1·73 m2 or more to first eGFR of less than 30 mL/min per 1·73 m2 (the therapeutic trial window). Findings Between Jan 18, 2010, and July 25, 2022, 27 285 participants were recruited to RaDaR. Median follow-up time from diagnosis was 9·6 years (IQR 5·9–16·7). RaDaR participants had significantly higher 5-year cumulative incidence of kidney failure than 2·81 million UK patients with all-cause chronic kidney disease (28% vs 1%; p<0·0001), but better survival rates (standardised mortality ratio 0·42 [95% CI 0·32–0·52]; p<0·0001). Median age at kidney failure, median age at death, time from start of dialysis to death, time from diagnosis to eGFR thresholds, and therapeutic trial window all varied substantially between rare diseases. Interpretation Patients with rare kidney diseases differ from the general population of individuals with chronic kidney disease: they have higher 5-year rates of kidney failure but higher survival than other patients with chronic kidney disease stages 3–5, and so are over-represented in the cohort of patients requiring kidney replacement therapy. Addressing unmet therapeutic need for patients with rare kidney diseases could have a large beneficial effect on long-term kidney replacement therapy demand. Funding RaDaR is funded by the Medical Research Council, Kidney Research UK, Kidney Care UK, and the Polycystic Kidney Disease Charity
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