22 research outputs found

    G-189A analytical simulation of the integrated waste management-water system using radioisotopes for thermal energy

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    An analytical simulation of the RITE-Integrated Waste Management and Water Recovery System using radioisotopes for thermal energy was prepared for the NASA-Manned Space Flight Center (MSFC). The RITE system is the most advanced concept water-waste management system currently under development and has undergone extended duration testing. It has the capability of disposing of nearly all spacecraft wastes including feces and trash and of recovering water from usual waste water sources: urine, condensate, wash water, etc. All of the process heat normally used in the system is produced from low penalty radioisotope heat sources. The analytical simulation was developed with the G189A computer program. The objective of the simulation was to obtain an analytical simulation which can be used to (1) evaluate the current RITE system steady state and transient performance during normal operating conditions, and also during off normal operating conditions including failure modes; and (2) evaluate the effects of variations in component design parameters and vehicle interface parameters on system performance

    Intake of food rich in saturated fat in relation to subclinical atherosclerosis and potential modulating effects from single genetic variants

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    The relationship between intake of saturated fats and subclinical atherosclerosis, as well as the possible influence of genetic variants, is poorly understood and investigated. We aimed to investigate this relationship, with a hypothesis that it would be positive, and to explore whether genetics may modulate it, using data from a European cohort including 3,407 participants aged 54–79 at high risk of cardiovascular disease. Subclinical atherosclerosis was assessed by carotid intima-media thickness (C-IMT), measured at baseline and after 30 months. Logistic regression (OR; 95% CI) was employed to assess the association between high intake of food rich in saturated fat (vs. low) and: (1) the mean and the maximum values of C-IMT in the whole carotid artery (C-IMTmean, C-IMTmax), in the bifurcation (Bif-), the common (CC-) and internal (ICA-) carotid arteries at baseline (binary, cut-point ≥ 75th), and (2) C-IMT progression (binary, cut-point > zero). For the genetic-diet interaction analyses, we considered 100,350 genetic variants. We defined interaction as departure from additivity of effects. After age- and sex-adjustment, high intake of saturated fat was associated with increased C-IMTmean (OR:1.27;1.06–1.47), CC-IMTmean (OR:1.22;1.04–1.44) and ICA-IMTmean (OR:1.26;1.07–1.48). However, in multivariate analysis results were no longer significant. No clear associations were observed between high intake of saturated fat and risk of atherosclerotic progression. There was no evidence of interactions between high intake of saturated fat and any of the genetic variants considered, after multiple testing corrections. High intake of saturated fats was not independently associated with subclinical atherosclerosis. Moreover, we did not identify any significant genetic-dietary fat interactions in relation to risk of subclinical atherosclerosis

    High Temperature Line Focus Central Receiver System cost and performance objectives

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    DOE is currently funding a study to determine if recent advances in line focus technology provide this solar concept with an economic potential comparable to the first generation Point Focus central receiver system for generation of electricity. This report was prepared in support of this effort and has the following specific objectives: (1) Determine the High Temperature Line Focus System (HTLFS) performance and cost goals required for the system to be economically competitive with first generation PFS; (2) Identify HTLFS plant physical and operational characteristics; and (3) Determine HTLFS sensitivities to capital equipment cost and subsystem efficiencies. A simplified analytical model was developed to determine the annual electrical energy generating capabilities and the plant capacity factor while accounting for both the daily and annual variation in solar position. The PFS performance data were based on recent DOE studies, while the HTLFS performance was obtained from sources at the Jet Propulsion Laboratories and at the Stanford Research Institute. The performance models were combined with the standard DOE economic model to generate the annual cost of electricity in terms of mills/kWh. Both the PFS and HTLFS were analyzed with this model using identical performance, operational and economic ground rules. The performance and cost characteristics of both systems were determined and judgements are made on their comparative merits

    Transient simulation of the MDAC receiver test panel in its STTF test configuration

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    The initial transient simulation of the McDonnell-Douglas (MDAC) receiver experiment integrated with the Solar Thermal Test Facility (STTF) configuration is described. The recently developed STTF computer simulation program was used for the simulation. The program was amended to include MDAC receiver experiment and the hardware modifications to the STTF facility as required to support the experiment. The thermal-hydraulic transients of the MDAC once-through steam generator for the 10 MW/sub t/ Solar Thermal Pilot Plant are essential in the study of the overall system performance of the receiver as well as for the design of its control system. The computer program was used to simulate the transient and steady-state characteristics and performance of the receiver test panel and to study key technical areas such as receiver panel/controller interaction and response. The program was also used to simulate part of the MDAC receiver test program at the STTF. The STTF computer simulation program was first modified to incorporate facilities changes for the MDAC test configuration. The original program contained individual modules to simulate the collector field, cooling subsystem, steam depressurization/desuperheat subsystem, feedwater and control subsystems. The feedwater module was modified to add the new regenerative heat exchanger which is required to increase feed water temperature to the MDAC receiver. A new subroutine was developed to simulate the MDAC receiver panel and the control module was modified to reflect MDAC experiment requirements.The completed program was then used to study some key technical issues including: 1) partial simulation of the panel test program at STTF; 2) receiver panel/controller interaction/response; and 3) receiver panel steady state and transient characteristics

    A priori-defined Mediterranean-like dietary pattern predicts cardiovascular events better in north Europe than in Mediterranean countries

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    Background The Mediterranean Diet (MD) is a model of healthy eating contributing to a favorable health status, but its clinical usefulness is still debated. The aim of this study was to relate the adherence to MD with the incidence of cardio/cerebro-vascular events (VEs) in north and south European participants of the IMPROVE study. Methods IMPROVE is an observational, longitudinal, prospective cohort study involving 3703 individuals from five European countries (Finland, Sweden, Netherlands, France and Italy). The study end-point was the incidence of the first combined cardio/cerebro-vascular event occurring during 36-months follow-up. At baseline, a dietary questionnaire about the usual intake during the year preceding enrollment was administered. Based on 7 nutritional items, a MD Score was constructed in which minimal adherence was 0 and maximal adherence was 7. Results Latitude was the strongest determinant of MD score (p < 0.001). VEs occurred in 215 participants. The incidence of VEs was the highest in subjects with MD score 0–1, lower in those with score 2–3 and the lowest in those with score ≥ 4. MD score remained significantly associated with subsequent VEs after adjustment for confounders (hazard ratio for one-point increment of the score = 0.75, p < 0.001) and the association was stronger in northern than in southern countries (p = 0.04 for MD Score × latitude interaction). Conclusions The MD adherence score based on a simple dietary questionnaire detects changes of risk of VEs. According to our findings north Europeans appear to benefit most from VE-prevention when their diet is altered to the MD diet

    Alcohol consumption in relation to carotid subclinical atherosclerosis and its progression: results from a European longitudinal multicentre study

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    Background/Aim: The association between alcohol consumption and subclinical atherosclerosis is still unclear. Using data from a European multicentre study, we assess subclinical atherosclerosis and its 30-month progression by carotid intima-media thickness (C-IMT) measurements, and correlate this information with self-reported data on alcohol consumption. Methods: Between 2002–2004, 1772 men and 1931 women aged 54–79&nbsp;years with at least three risk factors for cardiovascular disease (CVD) were recruited in Italy, France, Netherlands, Sweden, and Finland. Self-reported alcohol consumption, assessed at baseline, was categorized as follows: none (0&nbsp;g/d), very-low (0 − 5&nbsp;g/d), low (&gt; 5 to ≤ 10&nbsp;g/d), moderate (&gt; 10 to ≤ 20&nbsp;g/d for women, &gt; 10 to ≤ 30&nbsp;g/d for men) and high (&gt; 20&nbsp;g/d for women, &gt; 30&nbsp;g/d for men). C-IMT was measured in millimeters at baseline and after 30&nbsp;months. Measurements consisted of the mean and maximum values of the common carotids (CC), internal carotid artery (ICA), and bifurcations (Bif) and whole carotid tree. We used quantile regression to describe the associations between C-IMT measures and alcohol consumption categories, adjusting for sex, age, physical activity, education, smoking, diet, and latitude. Results: Adjusted differences between median C-IMT values in different levels of alcohol consumption (vs. very-low) showed that moderate alcohol consumption was associated with lower C-IMTmax[− 0.17(95%CI − 0.32; − 0.02)], and Bif-IMTmean[− 0.07(95%CI − 0.13; − 0.01)] at baseline and decreasing C-IMTmean[− 0.006 (95%CI − 0.011; − 0.000)], Bif-IMTmean[− 0.016(95%CI − 0.027; − 0.005)], ICA-IMTmean[− 0.009(95% − 0.016; − 0.002)] and ICA-IMTmax[− 0.016(95%: − 0.032; − 0.000)] after 30&nbsp;months. There was no evidence of departure from linearity in the association between alcohol consumption and C-IMT. Conclusion: In this European population at high risk of CVD, findings show an inverse relation between moderate alcohol consumption and carotid subclinical atherosclerosis and its 30-month progression, independently of several potential confounders
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