122 research outputs found

    Influence of shot peening on high-temperature corrosion and corrosion-fatigue of nickel based superalloy 720Li

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    High-temperature corrosion fatigue, a combination of corrosion with a fatigue cycle, is an emerging generic issue affecting power generation and aero gas turbine engines and has the potential to limit component life. Historically, surface treatments, such as shot peening have been used to improve component life and have been optimised for fatigue response. Research into optimisation of shot peening techniques for hot corrosion and high-temperature corrosion fatigue has shown 6–8A 230H 200% coverage to provide overall optimum performance for nickel-based superalloy 720Li based on the limited data within this study. Utilisation of electron backscatter diffraction techniques, in combination with detailed assessment of corrosion products have been undertaken as part of this work. The resultant cold-work visualisation technique provides a novel method of determining the variation in material properties due to the shot peening process and the interaction with hot corrosion. Through this work it has been shown that all three shot peening outputs must be considered to minimise the effect of corrosion fatigue, the cold work, residual stress and surface roughness. Further opportunity for optimisation has also been identified based on this work

    An experimental study investigating the effect of pain relief from oral analgesia on lumbar range of motion, velocity, acceleration and movement irregularity

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    Background Movement alterations are often reported in individuals with back pain. However the mechanisms behind these movement alterations are not well understood. A commonly cited mechanism is pain. The aim of this study was to investigate the effect of pain reduction, from oral analgesia, on lumbar kinematics in individuals with acute and chronic low back pain. Methods A prospective, cross-sectional, experimental repeated-measures design was used. Twenty acute and 20 chronic individuals with low back pain were recruited from General Practitioner and self-referrals to therapy departments for low back pain. Participants complained of movement evoked low back pain. Inertial sensors were attached to the sacrum and lumbar spine and used to measure kinematics. Kinematic variables measured were range of motion, angular velocity and angular acceleration as well as a determining movement irregularity (a measure of deviation from smooth motion). Kinematics were investigated before and after administration of oral analgesia to instigate pain reduction. Results Pain was significantly reduced following oral analgesia. There were no significant effects on the kinematic variables before and after pain reduction from oral analgesia. There was no interaction between the variables group (acute and chronic) and time (pre and post pain reduction). Conclusion The results demonstrate that pain reduction did not alter lumbar range of motion, angular velocity, angular acceleration or movement irregularity questioning the role of pain in lumbar kinematics

    Combined analgesics in (headache) pain therapy: shotgun approach or precise multi-target therapeutics?

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    <p>Abstract</p> <p>Background</p> <p>Pain in general and headache in particular are characterized by a change in activity in brain areas involved in pain processing. The therapeutic challenge is to identify drugs with molecular targets that restore the healthy state, resulting in meaningful pain relief or even freedom from pain. Different aspects of pain perception, i.e. sensory and affective components, also explain why there is not just one single target structure for therapeutic approaches to pain. A network of brain areas ("pain matrix") are involved in pain perception and pain control. This diversification of the pain system explains why a wide range of molecularly different substances can be used in the treatment of different pain states and why in recent years more and more studies have described a superior efficacy of a precise multi-target combination therapy compared to therapy with monotherapeutics.</p> <p>Discussion</p> <p>In this article, we discuss the available literature on the effects of several fixed-dose combinations in the treatment of headaches and discuss the evidence in support of the role of combination therapy in the pharmacotherapy of pain, particularly of headaches. The scientific rationale behind multi-target combinations is the therapeutic benefit that could not be achieved by the individual constituents and that the single substances of the combinations act together additively or even multiplicatively and cooperate to achieve a completeness of the desired therapeutic effect.</p> <p>As an example the fixesd-dose combination of acetylsalicylic acid (ASA), paracetamol (acetaminophen) and caffeine is reviewed in detail. The major advantage of using such a fixed combination is that the active ingredients act on different but distinct molecular targets and thus are able to act on more signalling cascades involved in pain than most single analgesics without adding more side effects to the therapy.</p> <p>Summary</p> <p>Multitarget therapeutics like combined analgesics broaden the array of therapeutic options, enable the completeness of the therapeutic effect, and allow doctors (and, in self-medication with OTC medications, the patients themselves) to customize treatment to the patient's specific needs. There is substantial clinical evidence that such a multi-component therapy is more effective than mono-component therapies.</p

    The Evolution and Cultural Framing of Food Safety Management Systems – Where from and Where next?

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    The aim of this paper is to review the development of food safety management systems (FSMS) from their origins in the 1950s to the present. The food safety challenges in modern food supply systems are explored and it is argued that there is the need for a more holistic thinking approach to food safety management. The narrative review highlights that whilst the transactional elements of how FSMS are developed, validated, implemented, monitored and verified remains largely unchanged, how organizational culture frames the operation and efficacy of FSMS is becoming more important. The evolution of a wider academic and industry understanding of both the influence of food safety culture (FS-culture) and also how such culture frames and enables, or conversely restricts the efficacy of the FSMS is crucial for consumer wellbeing. Potential research gaps worthy of further study are identified as well as recommendations given for the application of the research findings within the food industry

    Analysis of a Segmented Compliant Deployable Boom for CubeSat Magnetometer Missions

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    An Analog Wavelet Chip for Speech Compression

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    This paper describes the theory and implementation in CMOS technology of a circuit which performs analog wavelet decompositions of a one-dimensional (e.g., sound) input. The circuit is based on the Analog VLSI techniques described by Carver Mead in Analog VLSI and Neural Systems [1]. The analog wavelet outputs are the output of a logarithmically scaled set of bandpass filters; each band is sampled at a rate proportional to the Nyquist rate of the highest frequency content of that band. The result is a matrix of discrete points describing the input signal as a function of both frequency and time. The filter function of each band is gaussian shaped in order to best resolve the uncertainty relation between time and frequency at each sampled point. This chip has been designed by Tim Edwards under the direction of Michael Godfrey, and fabricated by Zilog Corporation of Campbell, California. Zilog provided the funding for this project. 1 Overview This paper describes the Analog Wavelet Tran..
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