Performance of an annual combustor designed for a low-cost turbojet engine

Performance tests were conducted on a combustor designed for use in a low-cost turbojet engine. Low-cost features included the use of very inexpensive simplex fuel nozzles and combustor liners of perforated sheet material. Combustion efficiencies at the altitude-cruise and sea-level design points were approximately 94 and 96 percent, respectively. The combustor isothermal total-pressure loss was 8.8 percent at the altitude-cruise-condition diffuser-inlet Mach number of 0.335. The combustor-exit temperature pattern factor was less than 0.3 at the altitude-cruise, sea-level-cruise, and sea-level-static design conditions. The combustor-exit average radial temperature profiles at all conditions were in very good agreement with the design profile. The intense mixing required because of the very high combustor heat-release rate had an adverse effect on ignition capability at altitude windmilling design conditions

The NASA pollution-reduction technology program for small jet aircraft engines

Three advanced combustor concepts, designed for the AiResearch TFE 731-2 turbofan engine, were evaluated in screening tests. Goals for carbon monoxide and unburned hydrocarbons were met or closely approached with two of the concepts with relatively modest departures from conventional combustor design practices. A more advanced premixing/prevaporizing combustor, while appearing to have the potential for meeting the oxides of nitrogen goal as well, will require extensive development to make it a practical combustion system. Smoke numbers for the two combustor concepts were well within the EPA smoke standard. Phase 2, Combustor-Engine Compatibility Testing, which is in its early stages, and planned Phase 3, Combustor-Engine Demonstration Testing, are also described

Banks on Board

As part of a series of related papers, the authors examine the conceptual foundations of German and American corporate governance, specifically highlighting the role of banks' relationships to corporations and the stock market. This paper focuses on how the regulatory and macroeconomic environments of the two countries helped shape how banks, especially money-centred bankers, actually interacted with their clients. Prior to 1914, despite many regulatory obstacles, American banks wielded more power over U.S. corporations than the legendary German ones because they had more “opportunities” for intervention. The U.S. suffered larger booms and busts (“panics” and bankruptcies), had more foreign investment, as well as saw more corporate consolidation than in Germany. By contrast, German companies seemed to have less need for active bank management and largely maintained their distance from activist banks, although German banks could potentially wield great power through board membership and proxy voting. Additionally, German regulators and investors turned more readily to banks to bolster controls on equity and debt capital markets to dampen dangerous speculation of “productive assets.” They encouraged banks to play a crucial intermediary role in solving the agency problem in firms and correcting the perceived weaknesses of financial markets—unlike U.S. regulators. Germans also expected banks to save companies from financial distress, but these occasions were more rare in Germany than in the United States. Surprisingly, the debates in Germany and the U.S. about the role of banks had many common features, yet the two countries increasingly found alternative solutions to classic corporate governance dilemmas. Whereas American regulators tended to suspect banks' insider relationship with companies and stock markets, and then endeavored to destroy this “money trust,” German regulators turned to banks as institutional stabilizers to tame market turbulence and speculation. Over time, they bolstered rather than undermined banks' special relationship to firms and capital markets. Key institutional choices set the stage for a much greater divergence during the interwar period.banking ; corporate governance

The NASA broad-specification fuels combustion technology program: An assessment of phase 1 test results

An assessment is made of the results of Phase 1 screening testing of current and advanced combustion system concepts using several broadened-properties fuels. The severity of each of several fuels-properties effects on combustor performance or liner life is discussed, as well as design techniques with the potential to offset these adverse effects. The selection of concepts to be pursued in Phase 2 refinement testing is described. This selection takes into account the relative costs and complexities of the concepts, the current outlook on pollutant emissions control, and practical operational problems

Pre- and pro-biotics may improve mineral absorption and retention in the growing male rat : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Nutritional Science at Massey University, Turitea, Palmerston North, New Zealand

Probiotics are bacteria, which reside in the large intestine and concur beneficial health effects on their host. Their abundance can be selectively-stimulated by prebiotics, such as fructo-oligosaccharide (FOS); prebiotics are oligosaccharides, which are not digested in the small intestine, but pass into the large intestine where they are fermented into short-chain fatty acids. Several studies have suggested that prebiotics may improve mineral absorption. This study aimed to determine the effects of pro- and pre-biotic supplementation on mineral absorption and bone quality in growing male rats. Sixty three-week old male Sprague-Dawley rats were randomised into five groups and fed either a high-calcium milk powder (HCMP) with or without a probiotic added (groups were subsequently named HCMP - and HCMP + respectively), or HCMP and vitamin K with or without the probiotic (HCMPK - and HCMPK +), or the HCMP with FOS replacing the sucrose in other diets, and the probiotic (the dietary group was named FOS). Animals were maintained on diets for 10 weeks. Balance studies were carried out during weeks 3 - 4 and 8 - 9 of the study. The earlier balance study suggested that dietary interventions may affect mineral absorption. The latter balance study, however, showed no discernable differences between groups. Several reasons were postulated for this. Active-absorption may have been down-regulated as a result of long-term supplementation, or an increased abundance of probiotics could cause an elevation of nutritional demands. Alternatively, supplementation may not prove beneficial once animals had passed their period of peak absorption. Bone resorption and formation did not appear to have been altered as a result of dietary intervention, when measured after 10-weeks. Bone mineral density and content, calcium, magnesium, zinc and ash contents and bone biomechanical testing also showed no significant differences between dietary groups. Further research is required to determine whether results obtained were due to long-term supplementation and / or due to the joint-supplementation of pre- and pro-biotics

Experience of a tutor centric model for sonography training of emergency department registrars in an Australian urban emergency department 2009–2012

Purpose: To assess the impact of a regular sonographer proctored training program for emergency medicine trainees in the use of Emergency Department bedside ultrasound Methods: Emergency Department (ED) Registrars in the Swan District Hospital ED were provided with proctored instruction in bedside ultrasound in performance of extended focused assessment sonography in trauma (eFAST) and abdominal aortic aneurysm (AAA) detection. Training was conducted by credentialed sonographers for individual trainees in a 1:1 or 1:2 setting for 1 hour on a weekly basis. Registrars who trained in the Department between Jan 2009 to Dec 2012 were invited to participate in a survey conducted between June-August 2013 designed to assess the impact of training on their confidence and use of bedside sonography. Results: Registrars reported increased perception of their skill level in AAA and eFAST post-training. High levels of confidence in their ability to adjust machine settings for image optimization, recognition of free fluid in the abdomen and ability to recognise an AAA were also reported. The participants that completed at least 10 hours of training and at least 20 scans showed significantly greater improvement in their perception of skill and confidence levels than those with less time. Registrars reported training was of significant benefit, improving their confidence in obtaining good quality images and their understanding of the equipment, which contributed to them obtaining accreditation. Benefits were ongoing and 50% of participants reported using ultrasound in clinical practice at least 3 times per week and a further 30% at least weekly after leaving ED. Conclusion: Proctored training in the clinical context for ED registrars resulted in improvement in skills, confidence and willingness to maintain skills through practice in the clinical context over the long-term

20 questions on Adaptive Dynamics

Abstract Adaptive Dynamics is an approach to studying evolutionary change when fitness is density or frequency dependent. Modern papers identifying themselves as using this approach first appeared in the 1990s, and have greatly increased up to the present. However, because of the rather technical nature of many of the papers, the approach is not widely known or understood by evolutionary biologists. In this review we aim to remedy this situation by outlining the methodology and then examining its strengths and weaknesses. We carry this out by posing and answering 20 key questions on Adaptive Dynamics. We conclude that Adaptive Dynamics provides a set of useful approximations for studying various evolutionary questions. However, as with any approximate method, conclusions based on Adaptive Dynamics are valid only under some restrictions that we discuss

No Substitute for the 'P'-Word in Financial Rescue

Three months and three-hundred billion dollars of bank rescue efforts have gotten bogged down in a widespread and irrational fear among policymakers: the fear of trying to put a price on banks’ troubled assets. So profound is this fear that the Bush Treasury opted instead for the “suitcase approach,” where large sums of cash were delivered to banks (solvent and insolvent alike) with few strings attached. The government needs to restore the banking sector, while protecting the interests of taxpayers. There is no substitute for the P-word.Auctions, financial auctions, financial crisis

Fear Conditioning and Extinction: Examining the Role of GSK3β ser 389

GSK3β is a serine threonine kinase that has been shown to influence numerous biological and psychological interactions, including the regulation of cell survival and cell death, as well as influencing mood disorders such as major depressive disorder and bipolar disorder. Preliminary data from our lab showed an exaggerated conditioned fear response in homozygous GSK3β knock-in (GSK3β KI) mice, which lacked the ability to phosphorylate GSK3β at the ser 389 site due to a serine to alanine substitution. Based on heightened fear responses previously observed in our lab, we predicted that increased expression GSK3β would result in a prolonged and heightened fear response, as GSK3β expression would interfere with the ability to turn off fear of a conditioned stimulus. These mutants were given five tone plus shock fear conditioning trials, followed by six days of tone alone fear extinction training. In contrast to our preliminary data, GSK3β KI mice did not show exaggerated conditioned fear, and showed no significant differences to wild type mice in fear extinction. To examine if these results were influenced by the age of the mice, a second study was conducted using two different age subsets of GSK3β KI mice. The results demonstrated that there were no significant differences in fear acquisition or extinction based on age

Impaired contextual modulation of memories in PTSD: an fMRI and psychophysiological study of extinction retention and fear renewal

Post-traumatic stress disorder (PTSD) patients display pervasive fear memories, expressed indiscriminately. Proposed mechanisms include enhanced fear learning and impaired extinction or extinction recall. Documented extinction recall deficits and failure to use safety signals could result from general failure to use contextual information, a hippocampus-dependent process. This can be probed by adding a renewal phase to standard conditioning and extinction paradigms. Human subjects with PTSD and combat controls were conditioned (skin conductance response), extinguished, and tested for extinction retention and renewal in a scanner (fMRI). Fear conditioning (light paired with shock) occurred in one context, followed by extinction in another, to create danger and safety contexts. The next day, the extinguished conditioned stimulus (CS+E) was re-presented to assess extinction recall (safety context) and fear renewal (danger context). PTSD patients showed impaired extinction recall, with increased skin conductance and heightened amygdala activity to the extinguished CS+ in the safety context. However, they also showed impaired fear renewal; in the danger context, they had less skin conductance response to CS+E and lower activity in amygdala and ventral-medial prefrontal cortex compared with combat controls. Control subjects displayed appropriate contextual modulation of memory recall, with extinction (safety) memory prevailing in the safety context, and fear memory prevailing in the danger context. PTSD patients could not use safety context to sustain suppression of extinguished fear memory, but they also less effectively used danger context to enhance fear. They did not display globally enhanced fear expression, but rather showed a globally diminished capacity to use contextual information to modulate fear expression