446 research outputs found

    Performance of a self-lifting linear air contact

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    An investigation into the performance of a self-levitating linear air bearing that functions on the squeeze film principle was conducted and a detailed set of results describing its floating characteristics at various operating parameters is presented. Experimentally assessed performance of the bearing was compared with performance predicted by a computer model of the bearing

    Use of near field acoustic levitation sliding contact

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    This paper presents an investigation into producing self-levitation effect using piezo-electric actuators (PZT). Self-levitation has been demonstrated and results are presented and discussed. A relationship between the levitation distance and weight of the levitating sample has been found. In addition the orientation and position of the PZTs has been found to affect the levitation distance. Modal shapes of the vibration plates used have been produced through modelling annd found to accurately correlate with the experimental results found. Additional evidence suggests that the type of vibration plate material affects the separation distance, possibly due to the material's properties of acoustic reflection

    Improving healthcare through human city interaction

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    The study of information technology has given insufficient focus to a) the structural factors and b) the community perspective. As information systems become increasingly integrated with human systems these wider influences are more important than ever. Human city interaction concepts including their interplay with cyber-physical systems and social computing are appropriated to healthcare. Through Structuration Theory, insights are given into how healthcare through the human city interaction lens can most effectively be improved

    Development of an ASIC for CCD readout at the vertex detectors of the intrenational linear collider

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    The Linear Collider Flavour Identification Collaboration is developing sensors and readout electronics suitable for the International Linear Collider vertex detector. In order to achieve high data rates the proposed detector utilises column parallel CCDs, each read out by a custom designed ASIC. The prototype chip (CPR2) has 250 channels of electronics, each with a preamplifier, 5-bit flash ADC, data sparsification logic for identification of significant data clusters, and local memory for storage of data awaiting readout. CPR2 also has hierarchical 2-level data multiplexing and intermediate data memory, enabling readout of the sparsified data via the 5-bit data output bus

    Data compression for the Cassini radio and plasma wave instrument

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    The Cassini Radio and Plasma Wave Science experiment will employ data compression to make effective use of the available data telemetry bandwidth. Some compression will be achieved by use of a lossless data compression chip and some by software in a dedicated 80C85 processor. A description of the instrument and data compression system are included in this report. Also, the selection of data compression systems and acceptability of data degradation is addressed

    Defining Smart Community in the Context of Healthcare Efficiency in the UK: Mapping the Evolution of a Concept

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    This literature review article creates a new definition for the concept of smart community and applies the concept to the issue of improving healthcare efficiency in the UK. The definition emerges by mapping the evolution of the smart community concept from the mid-1990s up to 2020. The emergent concept is then applied to healthcare efficiency through discussion about related concepts including smart cities, coproduction, social capital, social computing, and cyber physical systems. The review takes a qualitative approach to exploring literature about concepts, an approach that recognises and engages with the complex interconnectedness of terminology in the digital sphere. Smart community was selected because it originated in response to financial crisis. The relevance to theory is creating a context-specific definition of smart community. By defining smart community in the context of healthcare, insights have emerged that could be useful to practice as well as theory

    Determination of the dispersion of low frequency waves downstream of a quasiperpendicular collisionless shock

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    International audienceA method of wave mode determination, which was announced in Balikhin and Gedalin, is applied to AMPTE UKS and AMPTE IRM magnetic field measurements downstream of supercritical quasiperpendicular shock. The method is based on the fact that the relation between phase difference of the waves measured by two satellites, Doppler shift equation, the direction of the wave propagation are enough to obtain the dispersion equation of the observed waves. It is shown that the low frequency turbulence mainly consists of waves observed below 1 Hz with a linear dependence between the absolute value of wave vector |k| and the plasma frame wave frequency. The phase velocity of these waves is close to the phase velocity of intermediate waves Vint = Vacos(?)

    Single-event upsets in the Cluster and Double Star Digital Wave Processor instruments

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    Radiation-induced upsets are an important issue for electronic circuits operating in space. Upsets due to solar protons, trapped protons, and galactic cosmic rays are frequently observed. Modeling the expected frequency of upsets is a necessary part of the design process for space hardware. The Cluster and Double Star spacecraft were respectively European and Chinese missions dedicated to the study of the wave and particle environment in the Earth's magnetosphere. All four Cluster spacecraft and one Double Star spacecraft included a Digital Wave Processor (DWP) instrument. The primary purpose of this instrument was as the central controller of the Wave Experiment Consortium. This paper investigates the occurrence of radiation-induced single-event upsets in these DWP instruments. The memory devices used in the DWP were not specifically radiation-hardened parts and so are relatively sensitive to single-event effects. We present the experience gained during the first 11 years of operation of the Cluster mission and the nearly 4 year lifetime of the Double Star TC-1 spacecraft and compare with models of the radiation environment
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