229 research outputs found

    A Study of Evaporation Heat Transfer Coefficient Correlations at Low Heat and Mass Fluxes for Pure Refrigerants and Refrigerant Mixtures

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    An average R12 refrigerant correlation has been developed for the mass flux range of 25-100 kg/m2-s and the heat flux range of 2-10 kW/m2. Refrigerant mixtures of 80% R22/lO% R141b and 65% R22/35% R123 have also been tested over asjrniJar range of conditions. Mixture heat transfer coefficients have been detennined and correlations for each mixture pair are presented. The R221R141b average correlation may have a strong dependence on changes in surface tension. The heat transfer coefficient of R22JR141b compares well with that of R12. The heat transfer coefficient of R22/R123 severely under performs R12.Air Conditioning and Refrigeration Center Project 0

    A.J. Scott and his circle

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    SIGLEAvailable from British Library Document Supply Centre- DSC:D38319/81 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Characterising variations in the salinity of deep groundwater systems: A case study from Great Britain (GB)

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    Study region The study region is Great Britain (GB), a small non-continental island landmass in North West Europe Study focus Data for Total Dissolved Solids (TDS) from groundwater samples can be used to characterise regional-scale variations in the quality of deep groundwater systems. Combined with information about typical well-depths, TDS data can be used to identify the presence of currently undeveloped fresh or brackish groundwater at depth that may require protection. This study considers the distribution of TDS with depth relative to sea level in the main GB aquifers and selected other key hydrogeological units, and demonstrates how useful insights can be obtained from data-led analyses of depth variations in groundwater chemistry if the regional context of hydrogeological systems is taken into account. New hydrogeological insights In GB, TDS varies over about five orders of magnitude, up to about 330,000 mg/L, with a general increase in mineralisation with depth. Overall, there is a transition from fresh 10,000 mg/L groundwater at about 700 m. Given that the 95 %tile depth of water wells is about 200 m, it is evident that there is currently undeveloped fresh groundwater at depth across large parts of the study area that may require protection, although it is inferred that TDS is not the only factor limiting exploitation and use of these deeper resources. As in this study, previous data-led analyses of fresh groundwater at depth have typically analysed TDS as depth below surface. However, if TDS data is analysed relative to sea level and in the context of regional hydrogeological information or models, additional insights can be gained on the distribution and controls on fresh groundwater at depth. Projecting TDS data into a 3D hydrogeological model of the study area shows that fresh groundwater at depth exhibits spatial coherence and is generally associated with relatively dee

    Sea Clutter Spectrum Studies Using Airborne Coherent Radar III

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    Control Systems Laboratory changed its name to Coordinated Science LaboratoryContract DA-36-039-SC-5669

    Environment and Rural Affairs Monitoring & Modelling Programme - ERAMMP Technical Annex 1: Soil nutrient management for improved land. Sustainable Farming Scheme. Evidence Review.

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    The Brief: Establish intervention logic for Soil Nutrient Management (SNM) plans across all improved agricultural land. Establish the environmental benefits including GHG emissions reduction, biodiversity, water quality and air quality which will be secured through the universal uptake of SNM plans. Identify the contribution that better SNM will make to the economic resilience and sustainability of Welsh agriculture

    Environment and Rural Affairs Monitoring & Modelling Programme ERAMMP - Technical Annex 2: Sward management. Sustainable Farming Scheme Evidence Review

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    The Brief: Establish the intervention logic for supporting the diversification of swards in improved grassland. Establish the Greenhouse Gas (GHG), water quality, air quality and economic benefits. Establish the environmental outcomes including GHG emissions reduction, biodiversity, water quality and air quality, which will be secured through diversification of sward management. Identify the contribution that sward diversification will make to the economic resilience and sustainability of Welsh agriculture

    National geological screening : the Hampshire Basin and adjoining areas

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    This report is the published product of one of a series of studies covering England, Wales and Northern Ireland commissioned by Radioactive Waste Management (RWM) Ltd. The report provides geological information about the Hampshire Basin and adjoining areas region to underpin the process of national geological screening set out in the UK’s government White Paper Implementing geological disposal: a framework for the long-term management of higher activity radioactive waste (DECC, 2014). The report describes geological features relevant to the safety requirements of a geological disposal facility (GDF) for radioactive waste emplaced onshore and up to 20 km offshore at depths between 200 and 1000 m from surface. It is written for a technical audience but is intended to inform RWM in its discussions with communities interested in finding out about the potential for their area to host a GDF

    Mean flow and spiral defect chaos in Rayleigh-Benard convection

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    We describe a numerical procedure to construct a modified velocity field that does not have any mean flow. Using this procedure, we present two results. Firstly, we show that, in the absence of mean flow, spiral defect chaos collapses to a stationary pattern comprising textures of stripes with angular bends. The quenched patterns are characterized by mean wavenumbers that approach those uniquely selected by focus-type singularities, which, in the absence of mean flow, lie at the zig-zag instability boundary. The quenched patterns also have larger correlation lengths and are comprised of rolls with less curvature. Secondly, we describe how mean flow can contribute to the commonly observed phenomenon of rolls terminating perpendicularly into lateral walls. We show that, in the absence of mean flow, rolls begin to terminate into lateral walls at an oblique angle. This obliqueness increases with Rayleigh number.Comment: 14 pages, 19 figure

    The prevalence and frequency of menstrual cycle symptoms are associated with women’s availability to train and compete: A study of 6,812 exercising women recruited using the STRAVA™ exercise app

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    Objectives: The menstrual cycle can affect sports participation and exercise performance. There are very few data on the specific menstrual cycle symptoms (symptoms during various phases of the cycle, not only during menstruation) experienced by exercising women. We aimed to characterise the most common symptoms; the number and frequency of symptoms; and we evaluated whether menstrual cycle symptoms were associated with sporting outcomes. Methods: 6,812 adult women of reproductive age (mean age: 38.3 (8.7) years) who were not using combined hormonal contraception were recruited via the STRAVA exercise app user database and completed a 39-part survey. Respondents were from seven geographical areas, and questions were translated and localised to each region (Brazil, n=1,288; France, n=1,911; Germany, n=1,178; Spain, n=1,204; UK & Ireland, n=2,311; and USA, n=2,479). The survey captured exercise behaviours; current menstrual status; the presence and frequency of menstrual cycle symptoms; medication use for symptoms; perceived effects of the menstrual cycle on exercise and work behaviours; and history of hormonal contraception use. We propose a novel Menstrual Symptom index (MSi) based on the presence and frequency of 18 commonly reported symptoms (range 0-54 where 54 would be all 18 symptoms each occurring very frequently). Results: The most prevalent menstrual cycle symptoms were mood changes/anxiety (90.6%), tiredness/fatigue (86.2%), stomach cramps (84.2%), and breast pain/tenderness (83.1%). After controlling for BMI, training volume and age, the Menstrual Symptom Index was associated with a greater likelihood of missing or changing training (OR= 1.09 (CI: 1.08,1.10); p<0.05), missing a sporting event/competition (OR= 1.07 (CI: 1.06,1.08); p=<0.05), absenteeism from work/academia (OR= 1.08 (CI: 1.07,1.09); p=<0.05), and use of pain medication (OR= 1.09 (CI: 1.08,1.09); p=<0.05). Conclusion: Menstrual cycle symptoms are very common in exercising women and women report that these symptoms compromise their exercise participation and work capacity. The Menstrual Symptom Index needs to be formally validated (psychometrics); at present it provides an easy way to quantify the frequency of menstrual cycle symptoms

    Assessing the potential impacts of a revised set of on-farm nutrient and sediment ‘basic’ control measures for reducing agricultural diffuse pollution across England

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    The need for improved abatement of agricultural diffuse water pollution represents cause for concern throughout the world. A critical aspect in the design of on-farm intervention programmes concerns the potential technical cost-effectiveness of packages of control measures. The European Union (EU) Water Framework Directive (WFD) calls for Programmes of Measures (PoMs) to protect freshwater environments and these comprise ‘basic’ (mandatory) and ‘supplementary’ (incentivised) options. Recent work has used measure review, elicitation of stakeholder attitudes and a process-based modelling framework to identify a new alternative set of ‘basic’ agricultural sector control measures for nutrient and sediment abatement across England. Following an initial scientific review of 708 measures, 90 were identified for further consideration at an industry workshop and 63 had industry support. Optimisation modelling was undertaken to identify a shortlist of measures using the Demonstration Test Catchments as sentinel agricultural landscapes. Optimisation selected 12 measures relevant to livestock or arable systems. Model simulations of 95% implementation of these 12 candidate ‘basic’ measures, in addition to business-as-usual, suggested reductions in the national agricultural nitrate load of 2.5%, whilst corresponding reductions in phosphorus and sediment were 11.9% and 5.6%, respectively. The total cost of applying the candidate ‘basic’ measures across the whole of England was estimated to be £450 million per annum, which is equivalent to £52 per hectare of agricultural land. This work contributed to a public consultation in 2016
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