136 research outputs found

    A Methodology for Afterburner Evaluation

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    A preliminary investigation of the performance of an afterburner module proposed by the Gas Turbine Research Establishment, Bangalore for the Kaveri engine has been carried out. The investigation, which was both theoretical and experimental, evaluated the af-terburner configuration on the basis of flame stability, combustion efficiency and total pressure loss. An evaluation methodology, which was formulated, has been employed to arrive at design modifications for improved performance

    An Experimental Study of the Performance of a Subscale Kerosene - Fuelled Ejector Ramjet at Simulated Takeoff

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    The ejector ramjet is a rocket based combined cycle propulsion system in which a rocket and ramjet are integrated to accrue synergistic benefits. A proof-of-concept experiment to augment the thrust of a simulated rocket by the induction of air through an ejector and the subsequent afterburning of kerosene fuel in it is described. Ejector ram-jet thrust augmentation ratios of up to around 1.1 at the simulated take off conditions have been achieved. The critical effect of the operating conditions and the ejector ramjet geometry, in particular the afterburner configuration, for achieving thrust augmentation ratios greater than one have been demonstrated

    Perspectives and Integration in SOLAS Science

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    Why a chapter on Perspectives and Integration in SOLAS Science in this book? SOLAS science by its nature deals with interactions that occur: across a wide spectrum of time and space scales, involve gases and particles, between the ocean and the atmosphere, across many disciplines including chemistry, biology, optics, physics, mathematics, computing, socio-economics and consequently interactions between many different scientists and across scientific generations. This chapter provides a guide through the remarkable diversity of cross-cutting approaches and tools in the gigantic puzzle of the SOLAS realm. Here we overview the existing prime components of atmospheric and oceanic observing systems, with the acquisition of ocean–atmosphere observables either from in situ or from satellites, the rich hierarchy of models to test our knowledge of Earth System functioning, and the tremendous efforts accomplished over the last decade within the COST Action 735 and SOLAS Integration project frameworks to understand, as best we can, the current physical and biogeochemical state of the atmosphere and ocean commons. A few SOLAS integrative studies illustrate the full meaning of interactions, paving the way for even tighter connections between thematic fields. Ultimately, SOLAS research will also develop with an enhanced consideration of societal demand while preserving fundamental research coherency. The exchange of energy, gases and particles across the air-sea interface is controlled by a variety of biological, chemical and physical processes that operate across broad spatial and temporal scales. These processes influence the composition, biogeochemical and chemical properties of both the oceanic and atmospheric boundary layers and ultimately shape the Earth system response to climate and environmental change, as detailed in the previous four chapters. In this cross-cutting chapter we present some of the SOLAS achievements over the last decade in terms of integration, upscaling observational information from process-oriented studies and expeditionary research with key tools such as remote sensing and modelling. Here we do not pretend to encompass the entire legacy of SOLAS efforts but rather offer a selective view of some of the major integrative SOLAS studies that combined available pieces of the immense jigsaw puzzle. These include, for instance, COST efforts to build up global climatologies of SOLAS relevant parameters such as dimethyl sulphide, interconnection between volcanic ash and ecosystem response in the eastern subarctic North Pacific, optimal strategy to derive basin-scale CO2 uptake with good precision, or significant reduction of the uncertainties in sea-salt aerosol source functions. Predicting the future trajectory of Earth’s climate and habitability is the main task ahead. Some possible routes for the SOLAS scientific community to reach this overarching goal conclude the chapter

    Canagliflozin and Cardiovascular and Renal Outcomes in Type 2 Diabetes Mellitus and Chronic Kidney Disease in Primary and Secondary Cardiovascular Prevention Groups

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    Background: Canagliflozin reduces the risk of kidney failure in patients with type 2 diabetes mellitus and chronic kidney disease, but effects on specific cardiovascular outcomes are uncertain, as are effects in people without previous cardiovascular disease (primary prevention). Methods: In CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation), 4401 participants with type 2 diabetes mellitus and chronic kidney disease were randomly assigned to canagliflozin or placebo on a background of optimized standard of care. Results: Primary prevention participants (n=2181, 49.6%) were younger (61 versus 65 years), were more often female (37% versus 31%), and had shorter duration of diabetes mellitus (15 years versus 16 years) compared with secondary prevention participants (n=2220, 50.4%). Canagliflozin reduced the risk of major cardiovascular events overall (hazard ratio [HR], 0.80 [95% CI, 0.67-0.95]; P=0.01), with consistent reductions in both the primary (HR, 0.68 [95% CI, 0.49-0.94]) and secondary (HR, 0.85 [95% CI, 0.69-1.06]) prevention groups (P for interaction=0.25). Effects were also similar for the components of the composite including cardiovascular death (HR, 0.78 [95% CI, 0.61-1.00]), nonfatal myocardial infarction (HR, 0.81 [95% CI, 0.59-1.10]), and nonfatal stroke (HR, 0.80 [95% CI, 0.56-1.15]). The risk of the primary composite renal outcome and the composite of cardiovascular death or hospitalization for heart failure were also consistently reduced in both the primary and secondary prevention groups (P for interaction >0.5 for each outcome). Conclusions: Canagliflozin significantly reduced major cardiovascular events and kidney failure in patients with type 2 diabetes mellitus and chronic kidney disease, including in participants who did not have previous cardiovascular disease

    Investigative Ramjet tests of the ERJV Ejector Ramjet

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    An investigation has been carried out to evaluate the design of the ERJV ejector ramjet combustor. The performance has been characterised and suggestions made for improvements. A design methodology has also been evolved for rapidly attaining potential ejector ramjet combustor configurations, which are suitable for flight demonstrations. A direct connect test facility, which included a subscale ejector ramjet combustor with four discrete angled air inlets, has been successfully commissioned .A novel cavity cascade integral fuel injector flame stabiliser was successfully developed and deployed in the ramjet combustor. The critical test conditions were those corresponding to the transition from the ejector ramjet mode to the pure ramjet mode and the initial ramjet mode when the combustor would experience relatively low pressures and temperatures . The combustor has been carefully tested under these conditions and found to exhibit excellent ignition, blow-off and combustion characteristics
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