Design and fabrication of the Mini-Brayton Recuperator (MBR)

Development of a recuperator for a 2.0 kW closed Brayton space power system is described. The plate-fin heat exchanger is fabricated entirely from Hastelloy X and is designed for 10 years continuous operation at 1000 K (1300 F) with a Xenon-helium working fluid. Special design provisions assure uniform flow distribution, crucial for meeting 0.975 temperature effectiveness. Low-cycle fatigue, resulting from repeated startup and shutdown cycles, was identified as the most critical structural design problem. It is predicted that the unit has a minimum fatigue life of 220 cycles. This is in excess of the BIPS requirement of 100 cycles. Heat transfer performance and thermal cycle testing with air, using a prototype unit, verified that all design objectives can be met

Development of a model to explain the sexual beliefs, intentions and behaviours of adolescents and young adults

In the last thirty years there have been many research studies which have examined the reasons why adolescents and young adults engage in sexual behaviours. Most of these studies have lacked a theoretical basis, Consequently there are many links made between variables, but no consistency across studies, or attempts to develop an underlying theory to explain the results. However, there have been theoretical models developed to explain adolescents’ and young adults’ sexual decision making. Unfortunately, many of these models have not been empirically validated. This thesis attempts to address these deficiencies in the literature by utilising a theory of behaviour and applying it to adolescent and young adult sexual decision making. This theory is the Theory of Planned Behaviour (TPB). Two longitudinal studies were conducted to examine the utility of an adaptation of the TPB to sexual decision making among adolescents and young adults. In the first study 58 adolescent males, aged between 14 years and 18 years participated in a longitudinal study using a questionnaire adapted from the Depth of Sexual Involvement Scale. In the second study, 194 young adults (156 female, 38 male) aged between 18 years and 21 years participated in a similar study. The first study found that intention to engage in behaviour was well predicted, although some of the variables in the model, did not in fact, contribute significantly to the prediction. The prediction of behaviour was less strong than that of intention. Study two found that intention to engage in behaviours was well predicted by the model. However, the degree to which intention led to behaviour was not well predicted. Overall, the results of these studies suggest that the TPB is a good theoretical basis from which to launch a systematic and theoretically informed explanation of adolescent and young adult sexual decision making. However, other factors may need to be added to the model to fully describe the decision making process and accurately predict behaviour. Suggestions are made for future research, as well as interventions that may arise as more knowledge is gathered using this paradigm

Studies Of The Pharmacological Effects Of Benzoic Acid Analogs On Thrombosis And Inflammation

Previous work in this laboratory demonstrated that a series of benzoic acid analogs, with only minor structural variations compared to ASA, displayed a wide variation in biological effects compared to ASA. The compounds studied include 2-propionyloxybenzoic acid (2-PBA), 3-propionyloxybenzoic acid (3-PBA), 2-acetylbenzoic acid (ABA), 3-methylphthalide (3-MP) and 3-hydroperoxy-3-methylphthalide (3HMP). The purpose of this study was to extend our knowledge of the effects of these compounds and the processes they modify by assessing the in vivo antithrombotic and anti-inflammatory activities and the inhibition of prostaglandin (PG) synthesis (including PGI(,2)) in related in vitro systems. The ultimate aim of this work is the design of agents with more specific anti-inflammatory and antithrombotic activities.;The systems studied were (1) ADP and collagen-stimulated platelet aggregation and release of ATP; (2) platelet PG synthesis products; (3) platelet cyclic nucleotide phosphodiesterase activity (PDE); (4) aorta PGI(,2)-like activity production; (5) aorta arachidonic acid (AA) metabolism; (6) electrical injury-induced thrombosis in a rat model; (7) carrageenin-induced pleurisy in a rat model and; (8) polymorphonuclear neutrophil (PMN) AA metabolism.;ABA appears to be a unique agent with both anti-inflammatory and antithrombotic activity not accountable by PG synthesis or PDE inhibition. This agent appears a likely candidate as an anti-inflammatory agent without antiplatelet activity. The hydroperoxide, 3HMP, appears as a particularly useful tool for the study of the mechanisms of cyclo-oxygenation and lipoxygenation of AA and the activation and inhibition of the enzyme systems involved.;These studies point to unique mechanisms of action of antithrombotic and anti-inflammatory activities with a series of benzoic acid analogs and suggest that PG synthesis does not totally account for either antithrombotic or anti-inflammatory activity

Thermal-structural design study of an airframe-integrated Scramjet

Design concepts are developed and evaluated for a cooled structures assembly for the Scramjet engine, for engine subsystems mass, volume, and operating requirements, and for the aircraft/engine interface. A thermal protection system was defined that makes it possible to attain a life of 100 hours and 1000 cycles. The coolant equivalence ratio at the Mach 10 maximum thermal loading condition is 0.6, indicating a capacity for airframe cooling. The mechanical design is feasible for manufacture using conventional materials. For the cooled structures in a six-module engine, the mass per unit capture area is 12.4 KN/sq m. The total weight of a six-module engine assembly including the fuel system is 14.73 KN

Thermal-structural design study of an airframe-integrated Scramjet

The development and evaluation of a design concept for the cooled structures assembly for the Scramjet engine is discussed. Development concepts for engine subsystems and design concepts for the aircraft/engine interface are included. A thermal protection system was defined which makes it possible to attain a life of 100 hr and 1000 cycles, the specified goal. The coolant equivalence ratio at the Mach 10 maximum thermal loading condition is 0.6, indicating a capacity for airframe cooling. The mechanical design is feasible for manufacture using conventional materials. For the cooled structures in a six module engine, the mass per unit capture area is 1256 kg/sq m. The total mass of a six module engine assembly including the fuel system is 1502 kg

Clinical utility of the Mood and Anxiety Symptom Questionnaire (MASQ) in a sample of young help-seekers

<p>Abstract</p> <p>Background</p> <p>The overlap between Depression and Anxiety has led some researchers to conclude that they are manifestations of a broad, non-specific neurotic disorder. However, others believe that they can be distinguished despite sharing symptoms of general distress. The Tripartite Model of Affect proposes an anxiety-specific, a depression-specific and a shared symptoms factor. Watson and Clark developed the Mood and Anxiety Symptom Questionnaire (MASQ) to specifically measure these Tripartite constructs. Early research showed that the MASQ distinguished between dimensions of Depression and Anxiety in non-clinical samples. However, two recent studies have cautioned that the MASQ may show limited validity in clinical populations. The present study investigated the clinical utility of the MASQ in a clinical sample of adolescents and young adults.</p> <p>Methods</p> <p>A total of 204 Young people consecutively referred to a specialist public mental health service in Melbourne, Australia were approached and 150 consented to participate. From this, 136 participants completed both a diagnostic interview and the MASQ.</p> <p>Results</p> <p>The majority of the sample rated for an Axis-I disorder, with Mood and Anxiety disorders most prevalent. The disorder-specific scales of the MASQ significantly discriminated Anxiety (61.0%) and Mood Disorders (72.8%), however, the predictive accuracy for presence of Anxiety Disorders was very low (29.8%). From ROC analyses, a proposed cut-off of 76 was proposed for the depression scale to indicate 'caseness' for Mood Disorders. The resulting sensitivity/specificity was superior to that of the CES-D.</p> <p>Conclusion</p> <p>It was concluded that the depression-specific scale of the MASQ showed good clinical utility, but that the anxiety-specific scale showed poor discriminant validity.</p

Turnover of IPS employment specialists: Rates and predictors

Background: There are anecdotal reports of high job turnover of Individual Placement and Support employment specialists. However, no studies have addressed this issue. Objective: To explore whether turnover rates among employment specialists are higher compared to public sector employees along with the correlates of turnover intentions. Methods: A repeated cross-sectional study collected data from 40 employment specialists in Norway using validated scales to measure job perceptions. Turnover intentions were the main outcome. Results: Turnover rate of employment specialists (45.0%) was significantly higher than the average turnover rate of other occupations in the public sector (27.1%) in the same geographical regions (x2 = 6.5, df = 1, p = 0.01). After adjusting for potential confounders, five factors remained significantly associated with turnover intentions in directions as expected: general job satisfaction (β= –0.33, p < 0.05), satisfaction with current work (β= –0.35, p < 0.05), satisfaction with supervision (β= –0.28, p < 0.05), work meaningfulness (β= –0.42, p < 0.05) and Negative emotionality personality trait (β= 0.58, p < 0.05). Conclusions: Addressing turnover will positively impact on productivity and job satisfaction of employment specialists along with continuity of employment support for people with mental health conditions.publishedVersio