148 research outputs found

    Condensation-free radiant cooling using infrared-transparent enclosures of chilled panels

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    Radiant cooling power in the humid climates is inherently limited by condensation. This research investigates a type of radiant cooling methodology whereby the cold temperature source is convectively and conductively isolated from the environment with a membrane transparent to visible radiation to allow supply temperatures to be decreased for radiant cooling systems in humid climates. We conduct an FTIR analysis on three candidate membrane materials and fabricate a prototype experimental test panel that allows for thermal performance evaluation at different panel orientation and depths. Our study shows that for a 5 °C chilled panel temperature, the exterior membrane surface temperature reaches 26 °C in a 32 °C / 70% RH environment resulting in an effective panel temperature of 15.8 °C. Such a panel construction would avoid condensation in many humid environments and allow for radiant cooling without any latent load handling

    QUEnch assiSTed (QUEST) MRI Used as a Novel Approach to Identify Reactive Oxygen Species as a Result of Experimental TBI

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    Introduction: Traumatic brain injury (TBI) generates reactive oxygen species (ROS), promoting inflammatory processes and impeding TBI recovery. Within the VA population, over 70% of military personnel that sustain a TBI receive opioid-based pain relief, however, opiates may actually exacerbate post-TBI complications through its documented recruitment of oxidative and inflammatory systems. Thus, we hypothesize that TBI and opioid treatment act synergistically to worsen post-TBI oxidative stress. Methods: Mice were exposed to either TBI or sham injury and administered morphine or saline in the acute post-injury period. Afterwards, neuroimaging was conducted using a novel technique, QUEnch assiSTed (QUEST) MRI, which compares standard MRI signals across mice that acutely receive an antioxidant “quench” therapy and those receiving saline as control. Therefore, differential MRI signals between these groups are an index of ROS generation. Changes in hippocampus and cortex signals were measured, as these structures are most commonly affected by TBI. Methylene blue and α-lipoic acid were used as antioxidants in the quenching step as they halt mitochondrial ROS production and scavenge excess ROS, respectively. Results: No significant changes in ROS levels were detected as a result of TBI, opioid exposure or their combination using QUEST MRI in either the cortex or hippocampus. Conclusions and Future Directions: While QUEST imaging did not yield significant changes between experimental groups, future work will include ex-vivo biochemical ROS analyses from harvested tissues, which will provide higher resolution quantification of oxidative processes than that of QUEST MRI

    Optimizing decomposition of software architecture for local recovery

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    Cataloged from PDF version of article.The increasing size and complexity of software systems has led to an amplified number of potential failures and as such makes it harder to ensure software reliability. Since it is usually hard to prevent all the failures, fault tolerance techniques have become more important. An essential element of fault tolerance is the recovery from failures. Local recovery is an effective approach whereby only the erroneous parts of the system are recovered while the other parts remain available. For achieving local recovery, the architecture needs to be decomposed into separate units that can be recovered in isolation. Usually, there are many different alternative ways to decompose the system into recoverable units. It appears that each of these decomposition alternatives performs differently with respect to availability and performance metrics. We propose a systematic approach dedicated to optimizing the decomposition of software architecture for local recovery. The approach provides systematic guidelines to depict the design space of the possible decomposition alternatives, to reduce the design space with respect to domain and stakeholder constraints and to balance the feasible alternatives with respect to availability and performance. The approach is supported by an integrated set of tools and illustrated for the open-source MPlayer software

    CALIPSO observations of wave-induced PSCs with near-unity optical depth over Antarctica in 2006-2007

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    International audienceGround-based and satellite observations have hinted at the existence of polar stratospheric clouds (PSCs) with relatively high optical depths, even if optical depth values are hard to come by. This study documents a type II PSC observed from spaceborne lidar, with visible optical depths up to 0.8. Comparisons with multiple temperature fields, including reanalyses and results from mesoscale simulations, suggest that intense small-scale temperature fluctuations due to gravity waves play an important role in its formation, while nearby observations show the presence of a potentially related type Ia PSC farther downstream inside the polar vortex. Following this first case, the geographic distribution and microphysical properties of PSCs with optical depths above 0.3 are explored over Antarctica during the 2006 and 2007 austral winters. These clouds are rare (less than 1% of profiles) and concentrated over areas where strong winds hit steep ground slopes in the Western Hemisphere, especially over the peninsula. Such PSCs are colder than the general PSC population, and their detection is correlated with daily temperature minima across Antarctica. Lidar and depolarization ratios within these clouds suggest they are most likely ice-based (type II). Similarities between the case study and other PSCs suggest they might share the same formation mechanisms

    Migrant birds and mammals live faster than residents

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    Billions of vertebrates migrate to and from their breeding grounds annually, exhibiting astonishing feats of endurance. Many such movements are energetically costly yet there is little consensus on whether or how such costs might influence schedules of survival and reproduction in migratory animals. Here we provide a global analysis of associations between migratory behaviour and vertebrate life histories. After controlling for latitudinal and evolutionary patterns, we find that migratory birds and mammals have faster paces of life than their non-migratory relatives. Among swimming and walking species, migrants tend to have larger body size, while among flying species, migrants are smaller. We discuss whether pace of life is a determinant, consequence, or adaptive outcome, of migration. Our findings have important implications for the understanding of the migratory phenomenon and will help predict the responses of bird and mammal species to environmental changeinfo:eu-repo/semantics/publishedVersio

    Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

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    Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

    Protection of construction pit for car-park building in Ljubljana

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    V diplomski nalogi je obravnavano varovanje gradbene jame za objekt parkirno garažne hiše v Ljubljani. Varovalna konstrukcija je bila izvedena s sidranimi slopi po tehnologiji injektiranja pod visokimi pritiski (jet grouting). Sidranje smo izvedli z začasnimi geotehničnimi sidri v enem ali dveh nivojih. V nalogi je podan pregled postopkov za izvedbo jet grouting slopov in začasnih geotehničnih sider po veljavnih standardih. Pozornost je posvečena načinom izvedbe, ki so uveljavljeni pri nas, in problemom, ki se pojavljajo zaradi odstopanja od zhatev tehnične regulative ali nezmožnosti upoštevanja le-te. To je delno posledica zastarele opreme in utečenih postopkov izvajanja del. Dodatno pa na to vplivajo tudi zahteve po čim cenejši izvedbi gradbenih del. V nalogi so predstavljene izkušnje pridobljene med izvedbo varovalne konstrukcije gradbene jame, rezultati kontrolnih preiskav in problemi, ki so se pojavili med izvedbo del, ter rešitve teh problemov. V fazi izvedbe varovalne konstrukcije iz jet grouting slopov smo največ pozornosti posvetili tehnologiji enofaznega postopka injektiranja in njeni učinkovitosti v danih razmerah. Pri izvedbi geotehničnih sider pa smo največ pozornosti posvetili vgradnji in napenjanju preskusnih sider. Na gradbišču nastali problemi so lahko tudi posledica nepopolne gradbene dokumentacije, vključno s starimi in pomanjkljivimi načrti sosednjih objektov. V nalogi je prav tako obravnavano reševanje problemov, povezanih z nepričakovano sestavo temeljnih tal. Ta je pomembno vplivala na težave in zamude pri izvedbi in nemoteno napredovanje del.The subject of this thesis is the execution construction pit for multi-storey car-park building in Ljubljana. The supporting structure was made with high pressure grouting (e.q jet grouting), and anchored with temporary ground anchors in one or two levels. An overview of jet grouting and temporary ground anchors procedures accoding to current standards is shown. A special attention is put on the currently valid execution of works in our country. We primarily examined the problems occurring due to the deviation from technical regulations or inability to stick to them, which may be the consequence of either old equipment or sticking to generally accepted procedures of the execution, as well as requirements for a cheaper execution. The thesis presents the description of experiences gained during the execution works, the results of control examinations, the problems that occurred during the execution and appropriate solutions. In the phase of the jet-grouting-piles execution, which were used as a supporting structure, the attention was on the technology of the single fluid system and its effectiveness in the ground, while with ground anchors the most attention was paid to ground anchor installation and. The problems occurring on the construction site are often result of an incomplete project documentation, often involving the old and incomplete documentation of neighbouring buildings. The solution of issues in relation to the unexpected ground conditions, which significantly delayed the execution of works, is examined

    Three-dimensional properties of Andes mountain waves observed by satellite: A case study

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    International audienceThe southern Andes region has been clearly identified in previous satellite and balloon observations and in global models as a "hot spot" of small-scale gravity wave activity, with monthly mean momentum fluxes exceeding 10 times background values in fall, winter, and spring seasons. This makes this region a focus of interest for global circulation and climate studies. We analyze a case study on 8 May 2006, combining observations from the Atmospheric Infrared Sounder instrument on the Aqua satellite and the High Resolution Dynamics Limb Sounder instrument of the Aura satellite to form a three-dimensional picture of the wave field. The observations show a widespread wave pattern over the southern Andes extending eastward over the south Atlantic. Simulations with the Weather Research Forecasting model clearly identify the waves as orographic in origin, but the observed wave pattern is far from the simple two-dimensional wave field forced by steady flow over a mountain ridge. The morphology of the pattern is consistent with three-dimensional linear theoretical calculations of downstream propagation and latitudinal focusing of mountain waves into the stratospheric jet. The observations confirm the importance of this process in the stratosphere, and we find the process also occurring in the global analysis and forecasts from the European Centre for Medium-Range Weather Forecasting. Our analysis evaluates some strengths and weaknesses of current orographic wave drag parameterizations in global models and the relevance of parameterization assumptions in global models with high resolution. Copyright 2011 by the American Geophysical Union
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