14,331 research outputs found

    Effect of Night Blinds on Open Integral Display Cabinets

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    The impact of night blinds on the product temperature performance and electrical energy consumption of an integral open multi-deck cabinet is investigated in this paper. The cabinet was tested at various environmental conditions to establish the impact of ambient temperature on the effectiveness of the blind in reducing the energy consumption of the cabinet during night-time operation. The cabinet was tested over a range of temperatures between 20 °C and 35 °C at a constant moisture content. The results indicate that the use of night blinds could produce energy savings of between 10% and 22% calculated on the basis of a 24 hour period of operation with the blind lowered for 12 hours out of the 24 hours. These energy savings lead to pay-back periods of between 2 and 4 years. The savings reduced with increasing ambient temperature due to the increase in the impact of infiltration and conduction across the blind at higher temperatures

    The quest for stable circumbinary companions to post-common envelope sdB eclipsing binaries Does the observational evidence support their existence?

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    Context. Period variations have been detected in a number of eclipsing close compact binary subdwarf B stars (sdBs) and these have often been interpreted as caused by circumbinary massive planets or brown dwarfs. Various evolutionary scenarios have been proposed for these stars, but a definite mechanism remains to be established. Equally puzzling is the formation of these putative circumbinary objects which must have formed either from the remaining post common envelope circumbinary disk or survived its evolution. Aims. In this paper we review the eclipse time variations (ETVs) exhibited by seven such systems and explore if there is conclusive evidence that the ETVs observed over the last two decades can reliably predict the presence of circumbinary bodies. Methods. We report 246 new observations of the seven sdB systems made between 2013 September and 2017 July using a worldwide network of telescopes. We combined our new data with previously published measurements to analyse the ETVs of these systems. Results. Our data shows that period variations cannot be modelled simply on the basis of circumbinary objects. This implies that more complex processes may be taking place in these systems. From eclipse time variations, it has historically been suggested that five of the seven binary systems reported herein had circumbinary objects. Based on our recent observations and analysis only three systems remain serious contenders. We find agreement with other observers that at least a decade of observations is required to establish reliable ephemeris. With longer observational baselines it is quite conceivable that the data will support the circumbinary object hypothesis of these binary systems. Also we generally agree with other observers that larger values of (O-C) residuals are found with secondary companions of spectral type M5/6 or earlier as a result of an Applegate type mechanismComment: 15 pages, 13 figures, 4 tables. 3 tables archived on CD

    Metastable Cosmic Strings in Realistic Models

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    We investigate the stability of the electroweak Z-string at high temperatures. Our results show that while finite temperature corrections can improve the stability of the Z-string, their effect is not strong enough to stabilize the Z-string in the standard electroweak model. Consequently, the Z-string will be unstable even under the conditions present during the electroweak phase transition. We then consider phenomenologically viable models based on the gauge group SU(2)L×SU(2)R×U(1)BLSU(2)_L \times SU(2)_R \times U(1)_{B-L} and show that metastable strings exist and are stable to small perturbations for a large region of the parameter space for these models. We also show that these strings are superconducting with bosonic charge carriers. The string superconductivity may be able to stabilize segments and loops against dynamical contraction. Possible implications of these strings for cosmology are discussed.Comment: 24 pages, 2 figures (available on request); HUTP-92/A032, Fermilab-Pub-92/228-

    Force and pitching moment variation of inverted aerofoils at high angles of attack in ground effect

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    The effect of ground proximity on the moment coefficient of inverted, two-dimensional aerofoils was investigated. The purpose of the study was to examine the effect of ground proximity on aerofoils post stall, in an effort to evaluate the use of active aerodynamics to increase the performance of a race car. The aerofoils were tested at angles of attack ranging from 0° – 135°. The tests were performed at a Reynolds number of 2.16 x 105 based on chord length. Forces and moments were calculated via the use of pressure taps along the centreline of the aerofoils. The RMIT Industrial Wind-Tunnel (IWT) was used for the testing. Normally 3m wide and 2m high, an extra contraction was installed and the section was reduced to form a width of 295mm. The wing was mounted between walls to simulate 2-D flow. The IWT was chosen as it would allow enough height to reduce blockage effect caused by the aerofoils when at high angles of incidence. The walls of the tunnel were pressure tapped to allow monitoring of the pressure gradient along the tunnel. Decreasing ground clearance was found to reduce pitch moment variation of the aerofoils with varied Angle of Attack (AoA). Decreasing ground clearance increased lift and decreased drag for varied Ao

    Automated Retrieval of Non-Engineering Domain Solutions to Engineering Problems

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    Organised by: Cranfield UniversityBiological inspiration for engineering design has occurred through a variety of techniques such as creation and use of databases, keyword searches of biological information in natural-language format, prior knowledge of biology, and chance observations of nature. This research focuses on utilizing the reconciled Functional Basis function and flow terms to identify suitable biological inspiration for function based design. The organized search provides two levels of results: (1) associated with verb function only and (2) narrowed results associated with verb-noun (function-flow). A set of heuristics has been complied to promote efficient searching using this technique. An example for creating smart flooring is also presented and discussed.Mori Seiki – The Machine Tool Compan

    Exploration Medical System Demonstration

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    BACKGROUND: Exploration class missions will present significant new challenges and hazards to the health of the astronauts. Regardless of the intended destination, beyond low Earth orbit a greater degree of crew autonomy will be required to diagnose medical conditions, develop treatment plans, and implement procedures due to limited communications with ground-based personnel. SCOPE: The Exploration Medical System Demonstration (EMSD) project will act as a test bed on the International Space Station (ISS) to demonstrate to crew and ground personnel that an end-to-end medical system can assist clinician and non-clinician crew members in optimizing medical care delivery and data management during an exploration mission. Challenges facing exploration mission medical care include limited resources, inability to evacuate to Earth during many mission phases, and potential rendering of medical care by non-clinicians. This system demonstrates the integration of medical devices and informatics tools for managing evidence and decision making and can be designed to assist crewmembers in nominal, non-emergent situations and in emergent situations when they may be suffering from performance decrements due to environmental, physiological or other factors. PROJECT OBJECTIVES: The objectives of the EMSD project are to: a. Reduce or eliminate the time required of an on-orbit crew and ground personnel to access, transfer, and manipulate medical data. b. Demonstrate that the on-orbit crew has the ability to access medical data/information via an intuitive and crew-friendly solution to aid in the treatment of a medical condition. c. Develop a common data management framework that can be ubiquitously used to automate repetitive data collection, management, and communications tasks for all activities pertaining to crew health and life sciences. d. Ensure crew access to medical data during periods of restricted ground communication. e. Develop a common data management framework that allows for scalability, extensibility, and interoperability of data sources and data users. f. Lower total cost of ownership for development and sustainment of peripheral hardware and software that use EMSD for data management. g. Provide a better standard of healthcare for crew members through reductions in the time required by crew and ground personnel to provide medical treatment and the number of crew errors experienced during treatment

    Rate controls on the chemical weathering of natural polymineralic material. II. Rate-controlling mechanisms and mineral sources and sinks for element release from four UK mine sites, and implications for comparison of laboratory and field scale weathering studies

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    Predictions of mine-related water pollution are often based on laboratory assays of mine-site material. However, many of the factors that control the rate of element release from a site, such as pH, water-rock ratio, the presence of secondary minerals, particle size, and the relative roles of surface-kinetic and mineral equilibria processes can exhibit considerable variation between small-scale laboratory experiments and large-scale field sites. Monthly monitoring of mine effluent and analysis of natural geological material from four very different mine sites have been used to determine the factors that control the rate of element release and mineral sources and sinks for major elements and for the contaminant metals Zn, Pb, and Cu. The sites are: a coal spoil tip; a limestone-hosted Pb mine, abandoned forthe last 200 a; a coal mine; and a slate-hosted Cu mine that was abandoned 150 a ago. Hydrogeological analysis of these sites has been performed to allow field fluxes of elements suitable for comparison with laboratory results to be calculated. Hydrogeological and mineral equilibrium control of element fluxes are common at the field sites, far more so than in laboratory studies. This is attributed to long residence times and low water-rock ratios at the field sites. The high water stor-ativity at many mine sites, and the formation of soluble secondary minerals that can efficiently adsorb metals onto their surfaces provides a large potential source of pollution. This can be released rapidly if conditions change significantly, as in,for example, the case of flooding or disturbance

    The Near Earth Asteroid Medical Conditions List

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    Purpose: The Exploration Medical Capability (ExMC) element is one of six elements within NASA s Human Research Program (HRP) and is responsible for addressing the risk of "the inability to adequately recognize or treat an ill or injured crewmember" for exploration-class missions. The Near Earth Asteroid (NEA) Medical Conditions List, constructed by ExMC, is the first step in addressing the above-mentioned risk for the 13-month long NEA mission. The NEA mission is being designed by NASA's Human Space Flight Architecture Team (HAT). The purpose of the conditions list is to serve as an evidence-based foundation for determining which medical conditions could affect a crewmember during the NEA mission, which of those conditions would be of concern and require treatment, and for which conditions a gap in knowledge or technology development exists. This information is used to focus research efforts and technology development to ensure that the appropriate medical capabilities are available for exploration-class missions. Scope and Approach: The NEA Medical Conditions List is part of a broader Space Medicine Exploration Medical Conditions List (SMEMCL), which incorporates various exploration-class design reference missions (DRMs). The conditions list contains 85 medical conditions which could occur during space flight and which are derived from several sources: Long-Term Surveillance of Astronaut Health (LSAH) in-flight occurrence data, The Space Shuttle (STS) Medical Checklist, The International Space Station (ISS) Medical Checklist, and subject matter expert opinion. Each medical condition listed has been assigned a clinical priority and a clinical priority rationale based on incidence, consequence, and mitigation capability. Implementation: The conditions list is a "living document" and as such, new conditions can be added to the list, and the priority of conditions on the list can be adjusted as the DRM changes, and as screening, diagnosis, or treatment capabilities change. The NEA medical conditions list was used recently as the basis for identifying gaps in in-flight medical evaluation (screening) capabilities. Learning Objectives: The audience will become familiar with the approach taken by NASA's Exploration Medical Capability element in addressing the risk of inability to recognize and treat medical conditions in the setting of a Near Earth Asteroid mission. Which one of the following statements is incorrect? a) The Near Earth Asteroid (NEA) medical conditions list includes 85 medical conditions which could occur during space flight. b) Each condition on the NEA medical conditions list has been assigned a clinical priority and a clinical priority rationale. c) The NEA medical conditions list targets a mission to Mars. d) The NEA medical conditions list should be viewed as a "living document" where new conditions can be added and clinical priorities adjusted to address changes in the design reference mission or medical capabilities. The incorrect answer is c). The NEA medical conditions list targets a mission to a Near Earth Asteroid

    Warming trends in summer heatwaves

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    The frequency and severity of heatwaves is expected to increase as the global climate warms. We apply crossing theory for the first time to determine heatwave properties solely from the distribution of daily observations without time‐correlation information. We use Central England Temperature timeseries to quantify how the simple increased occurrence of higher temperatures makes heatwaves (consecutive summer days with temperatures exceeding a threshold) more frequent and intense. We find an overall 2‐3‐fold increase in heatwave activity since the late 1800's. Week‐long heatwaves that on average return every 5 years were typically below ∼28°C and now typically exceed it. Our analysis takes as inputs average user‐specific heatwave properties. Its output pinpoints the range of temperatures for which changes in the distribution must be well‐resolved statistically in order to track how these heatwave properties are changing. This provides a quantitative benchmark for models used for the attribution of heatwaves

    Perceptions of facial dominance, trustworthiness and attractiveness predict managerial pay awards in experimental tasks

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    Positive associations between physical attractiveness and employee reward are well-documented within the organisational literature. Although the impact of facial cues to trustworthiness and dominance on a number of social outcomes has been established outside of the workplace, the extent to which they, in addition to attractiveness, affect pay at different managerial levels is yet to be investigated. This paper presents research into this issue using a face payment task for shop floor managers (Retail Managers) and senior managers (Heads of Retail Operations). Evaluations indicated that all three facial cues were positively associated with awarded pay at both managerial levels. Moreover, attractiveness had a significantly stronger link with shop- floor managers' than senior managers' pay, whereas perceived trustworthiness and perceived dominance had significantly stronger links with pay for senior managers than shop-floor managers. It further emerged that women were paid more in this experimental task where pay was awarded solely based on facial features and that the facial features were more predictive of women's than men's pay. Awareness of the role of physical cues in pay awards can be considered by organisations to reduce biases in remuneration
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