197 research outputs found

    Chemical protective clothing comfort study: thermal insulation and evaporative resistance from fabric to garment

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    The relationship between the Rct and Ret of textile material used in CPC and that obtained from CPC garment was investigated. It was found that the Rct and Ret of CPC fabric are reliable predictor for the Rct and Ret of CPC garments respectively. Air gap contributes significantly to the increase of the Rct of CPC garments and fabrics. Heat dissipation by water vapor transfer through CPC is a complex process and different from other kinds of clothing due to its low permeability or impermeability. Further studies on the influential factors of Ret of CPC garments are needed

    Analysis of heat stress associated with wearing chemical protective clothing using a numerical model

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    A numerical model was applied to evaluate heat stress under different thermal environmental conditions, activity intensities, and the effect of movement status on clothing properties when wearing a typical CPC. It was concluded that the ambient temperature and metabolic rate is strongly associated with heat stress and reduced the tolerance time. Although the manikin movement greatly affected the thermal insulation and evaporative resistance of CPC, the effects of movement on heat stress can be neglected

    Spatiotemporal assessment of PM<sub>2.5</sub>-related economic losses from health impacts during 2014–2016 in China

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    Background: Particulate air pollution, especially PM2.5, is highly correlated with various adverse health impacts and, ultimately, economic losses for society, however, few studies have undertaken a spatiotemporal assessment of PM2.5-related economic losses from health impacts covering all of the main cities in China. Methods: PM2.5 concentration data were retrieved for 190 Chinese cities for the period 2014&ndash;2016. We used a log-linear exposure&ndash;response model and monetary valuation methods, such as value of a statistical life (VSL), amended human capital (AHC), and cost of illness to evaluate PM2.5-related economic losses from health impacts at the city level. In addition, Monte Carlo simulation was used to analyze uncertainty. Results: The average economic loss was 0.3% (AHC) to 1% (VSL) of the total gross domestic product (GDP) of 190 Chinese cities from 2014 to 2016. Overall, China experienced a downward trend in total economic losses over the three-year period, but the Beijing&ndash;Tianjin&ndash;Hebei, Shandong Peninsula, Yangtze River Delta, and Chengdu-Chongqing regions experienced greater annual economic losses. Conclusions: Exploration of spatiotemporal variations in PM2.5-related economic losses from long-term health impacts could provide new information for policymakers regarding priority areas for PM2.5 pollution prevention and control in China

    Nonlinear flow in low permeability reservoirs: Modelling and experimental verification

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    The low-permeability reservoirs are of heavy heterogeneity, low permeability, fine oil-water passages, strong resistance during flow, and the significant interaction between solid and liquid interfaces causes the flow of fluid in reservoir deviating from the Darcy’s law. There is no agreement on the interaction between the various factors in seepage process and the influence of seepage law. The boundary layer exists when liquid flow in micro-tubes and nano-tubes, and the boundary layer decreases with the increase of driving force, and the maximum value of boundary layer ratio is equal to 1. Based on the capillary boundal model and the boundary layer theory, a new exponential seepage model for low permeability reservoirs was proposed. Some experiments of water flow with different pressure gradient were carried out in low permeability cores with permeability of 4 to 8 milidarcy in natural rock cores from an oilfield in China, and the nonlinear model is of good agreement with the single-phase water flooding experiments of these cores. The results demonstrate that the physical meaning of each parameter of the new model is clear and it can be applied to describe the nonlinear characteristics of low permeability reservoirs. The large driving force can overcome disadvantages in the developments of low permeability reservoirs.Cited as: Song, F., Bo, L., Zhang, S., Sun, Y. Nonlinear flow in low permeability reservoirs: Modelling and experimental verification. Advances in Geo-Energy Research, 2019, 3(1): 76-81, doi: 10.26804/ager.2019.01.0

    Differences in metabonomic profiles of abdominal subcutaneous adipose tissue in women with polycystic ovary syndrome

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    IntroductionPolycystic ovary syndrome (PCOS) is a complex endocrine disorder that often coexists with a metabolic disorder. Studies have demonstrated that the malfunction of adipose tissue, particularly abdominal adipose tissue, could exacerbate reproductive and metabolic problems in PCOS patients. Adipose tissue-secreted signaling mediators (e.g., lipids and metabolites) would then interact with other body organs, including the ovary, to maintain the systemic equilibrium.MethodsIn this study, we examined adipose samples from PCOS patients and unaffected individuals using a liquid chromatography–mass spectrometry-based metabonomics approach (LC–MS/MS). PCOS biomarkers were selected using multivariate statistical analysis.ResultsOur pathway analysis revealed that these differential metabolites could be engaged in inflammatory diseases and mitochondrial beta-oxidation. We further developed an in vitro PCOS cell model to examine the effects of hyperandrogenism on granulosa cells and related metabolic disorders. We noted that isoleucine recovered the promotive effect on cell apoptosis, inhibitory effect on cell proliferation, sex hormone secretion, and mitochondrial function induced by dehydroepiandrosterone. Our gas chromatography–mass spectrometry targeted analysis (GC–MS/MS) revealed that isoleucine was significantly decreased in PCOS patients.DiscussionBased on these results, we speculate that metabolome alterations are vital in ameliorating PCOS symptoms. This may be a novel therapeutic target for PCOS treatment. Our study provides preliminary evidence that these findings will enhance our ability to accurately diagnose and intervene in PCOS

    Investigation of the Convective Heat Transfer Coefficient of the Hand and Fingers in Firefighter Gloves Using a Thermal Hand

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    The heat transfer coefficients of the hands are critical inputs of the thermoregulation model that can simulate thermal responses of the hand and fingers. Besides, the hand has a greater surface area to mass ratio and complex anthropometric parameters, thus is extremely important in heat transfer and thermoregulation. However, the convective heat transfer coefficients of the fingers, palm, and dorsal of the hand are not fully investigated and understood. Accordingly, there is an urgent need for full understanding of the convective heat transfer coefficients in both the whole-hand and regional segments. The results of this study will provide guidance for the thermal model development, cold and burn injuries assessment, and design of high-performance protective gloves
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