7,739 research outputs found

    Reusable rocket engine turbopump health monitoring system, part 3

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    Degradation mechanisms and sensor identification/selection resulted in a list of degradation modes and a list of sensors that are utilized in the diagnosis of these degradation modes. The sensor list is divided into primary and secondary indicators of the corresponding degradation modes. The signal conditioning requirements are discussed, describing the methods of producing the Space Shuttle Main Engine (SSME) post-hot-fire test data to be utilized by the Health Monitoring System. Development of the diagnostic logic and algorithms is also presented. The knowledge engineering approach, as utilized, includes the knowledge acquisition effort, characterization of the expert's problem solving strategy, conceptually defining the form of the applicable knowledge base, and rule base, and identifying an appropriate inferencing mechanism for the problem domain. The resulting logic flow graphs detail the diagnosis/prognosis procedure as followed by the experts. The nature and content of required support data and databases is also presented. The distinction between deep and shallow types of knowledge is identified. Computer coding of the Health Monitoring System is shown to follow the logical inferencing of the logic flow graphs/algorithms

    Perceptions of coach-athlete relationship are more important to coaches than athletes in predicting dyadic coping and stress appraisals: An actor-partner independence mediation model

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    Most attempts to manage stress involve at least one other person, yet coping studies in sport tend to report an athlete’s individual coping strategies. There is a limited understanding of coping involving other people, particularly within sport, despite athletes potentially spending a lot of time with other people, such as their coach. Guided by the systemic-transactional model of stress and coping among couples (Bodenmann, 1995), from relationship psychology, we assessed dyadic coping, perceptions of relationship quality, and primary stress appraisals of challenge and threat among 158 coach–athlete dyads (n D 277 participants). The athletes competed at amateur (n D 123), semiprofessional (n D 31), or professional levels (n D 4). Coaches and athletes from the same dyad completed a measure of dyadic coping, coach–athlete relationship, and stress appraisals. We tested an Actor–Partner Interdependence Mediation Model to account for the non-independence of dyadic data. These actor–partner analyses revealed differences between athletes and coaches. Although the actor effects were relatively large compared to partner effects, perceptions of relationship quality demonstrated little impact on athletes. The mediating role of relationship quality was broadly as important as dyadic coping for coaches. These findings provide an insight in to how coach–athlete dyads interact to manage stress and indicate that relationship quality is of particular importance for coaches, but less important for athletes. In order to improve perceptions of relationship quality among coaches and athletes, interventions could be developed to foster positive dyadic coping among both coaches and athletes, which may also impact upon stress appraisals of challenge and threat

    Coupling a Self-Dual Tensor to Gravity in Six Dimensions

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    A recent result concerning interacting theories of self-dual tensor gauge fields in six dimensions is generalized to include coupling to gravity. The formalism makes five of the six general coordinate invariances manifest, whereas the sixth one requires a non-trivial analysis. The result should be helpful in formulating the world-volume action of the M theory five-brane.Comment: 7 pages, latex, no figure

    Analysis of pathogenic bacteria using exogenous volatile organic compound metabolites and optical sensor detection

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    A novel, low-cost and simple method for the detection of pathogenic bacteria is proposed. The approach is based on the generation of an exogenous volatile organic compound (VOC) produced by the addition of an enzyme substrate to the bacterial sample. The generated VOC is then trapped in agarose gel allowing colour development to take place; visual detection is then possible by both the naked eye and by colorimetric analysis. Agarose gel has been evaluated as both a suitable VOC trapping matrix and host for the colour-generating reagents. This proof of concept method allowed for the discrimination between β-glucosidase and β-alanyl aminopeptidase producing bacteria. Enterococcus faecium and Klebsiella pneumoniae are both β-glucosidase producers and generated a yellow colour within agarose gels upon enzymatic hydrolysis of 2-nitrophenyl-β-D-glucoside. Pseudomonas aeruginosa is a known β-alanyl aminopeptidase producer and was shown to hydrolyse the trifluoroacetic acid (TFA) salt of 3-amino-N-phenylpropanamide resulting in the development of an orange colour within agarose gels spiked with the sodium salt of 1,2-naphthoquinone-4-sulfonic acid. 3-Amino-N-phenylpropanamide (as its TFA salt) and 2-nitrophenyl-β-D-glucoside concentrations of 20 μg mL−1 (or 72 μmol L−1) and 100 μg mL−1 (or 332 μmol L−1), respectively were the minimum quantities required for colour production following 18 h of incubation. The use of 3-amino-N-phenylpropanamide, TFA salt indicated that synthesised enzyme substrates can be tailor-made to liberate exogenous VOCs for colour generation

    Operation of the HP2250 with the HP9000 series 200 using PASCAL 3.0

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    A computer program has been written to provide an interface between the HP Series 200 desktop computers, operating under HP Standard Pascal 3.0, and the HP2250 Data Acquisition and Control System. Pascal 3.0 for the HP9000 desktop computer gives a number of procedures for handling bus communication at various levels. It is necessary, however, to reach the lowest possible level in Pascal to handle the bus protocols required by the HP2250. This makes programming extremely complex since these protocols are not documented. The program described solves those problems and allows the user to immediately program, simply and efficiently, any measurement and control language (MCL/50) application with a few procedure calls. The complete set of procedures is available on a 5 1/4 inch diskette from Cosmic. Included in this group of procedures is an Exerciser which allows the user to exercise his HP2250 interactively. The exerciser operates in a fashion similar to the Series 200 operating system programs, but is adapted to the requirements of the HP2250. The programs on the diskette and the user's manual assume the user is acquainted with both the MCL/50 programming language and HP Standard Pascal 3.0 for the HP series 200 desktop computers

    Demonstration of earlier detection of Salmonella species from stool samples by using chromogenic media

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    Background: Salmonellosis is a worldwide public health issue and non-typhoid species are one of the most common causative agents of gastroenteritis in the western world.1 Typhoidal and Paratyphoidal salmonellae cause systemic syndromes characterised by sustained bacteraemia.2 Although the number of cases is under reported and therefore the incidence rates are underestimated,3 worldwide up to 1.3 billion non-typhoidal and an estimated 20 million typhoidal cases of Salmonella infection are reported annually.4,
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