Thermal design study of an air-cooled plug-nozzle system for a supersonic cruise aircraft

A heat-transfer design analysis has been made of an air-cooled plug-nozzle system for a supersonic-cruise aircraft engine. The proposed 10deg half-angle conical plug is sting supported from the turbine frame. Plug cooling is accomplished by convection and film cooling. The flight profile studied includes maximum afterburning from takeoff to Mach 2.7 and supersonic cruise at Mach 2.7 with a low afterburner setting. The calculations indicate that, for maximum afterburning, about 2 percent of the engine primary flow, removed after the second stage of the nine-stage compressor, will adequately cool the plug and sting support. Ram air may be used for cooling during supersonic-cruise operations, however. Therefore, the cycle efficiency penalty paid for air cooling the plug and sting support should be low

Unlimited simultaneous discrimination intervals in regression Technical report no. 90

Unlimited simultaneous discrimination intervals in linear regression

Computer-guided concentration-controlled trials in autoimmune disorders

A randomized concentration-controlled clinical trial (RCCCT) is an alternate experimental design to the standard dose-controlled study. In a RCCCT, patients are randomly assigned to predefined plasma or blood drug concentration ranges (low, medium, and high). With the caveat that concentration ranges are sufficiently separated, this design should enhance the ability to discover important concentration response relationships. FK-506, a potent and promising immunosuppressive agent for prevention and treatment of graft rejection, has shown significant clinical activity in some immune-mediated disorders. To implement the RCCCT design, a novel FK-506 intelligent dosing system (IDS) was used to guide all doses to prospectively achieve the target concentration range specified in the study protocol. Patients enrolled in these trials suffered from a variety of autoimmune disorders, including multiple sclerosis, primary biliary cirrhosis, psoriasis, autoimmune chronic active hepatitis, and nephrotic syndrome. We observed excellent predictive performance of the IDS for all patients. The accuracy (mean prediction error) of the IDS was −0.022 ng/ml and the precision (standard deviation of the prediction error) was 0.119 ng/ml. Thus, the IDS is both accurate and reproducible for autoimmune patients. We conclude that the RCCCT design, guided by an accurate and precise IDS, is an informative and cost-effective approach for evaluation of efficacy and safety of effective but highly toxic agents. © 1993 Raven Press, Ltd., New York

Fitting the Means to the Ends: One School’s Experience with Quantitative and Qualitative Methods in Curriculum Evaluation During Curriculum Change

Curriculum evaluation plays an important role in substantive curriculum change. The experience of the University of Texas Medical Branch (UTMB) with evaluation processes developed for the new Integrated Medical Curriculum (IMC) illustrates how evaluation methods may be chosen to match the goals of the curriculum evaluation process. Quantitative data such as ratings of courses or scores on external exams are useful for comparing courses or assessing whether standards have been met. Qualitative data such as students’ comments about aspects of courses are useful for eliciting explanations of observed phenomena and describing relationships between curriculum features and outcomes. The curriculum evaluation process designed for the IMC used both types of evaluation methods in a complementary fashion. Quantitative and qualitative methods have been used for formative evaluation of the new IMC courses. They are now being incorporated into processes to judge the IMC against its goals and objectives

Jet fuel property changes and their effect on producibility and cost in the U.S., Canada, and Europe

The effects of changes in properties and blending stocks on the refinery output and cost of jet fuel in the U.S., Canada, and Europe were determined. Computerized refinery models that minimize production costs and incorporated a 1981 cost structure and supply/demand projections to the year 2010 were used. Except in the West U.S., no changes in jet fuel properties were required to meet all projected demands, even allowing for deteriorating crude qualities and changes in competing product demand. In the West U.S., property changes or the use of cracked blendstocks were projected to be required after 1990 to meet expected demand. Generally, relaxation of aromatics and freezing point, or the use of cracked stocks produced similar results, i.e., jet fuel output could be increased by up to a factor of three or its production cost lowered by up to $10/cu m. High quality hydrocracked stocks are now used on a limited basis to produce jet fuel. The conversion of U.S. and NATO military forces from wide-cut to kerosene-based jet fuel is addressed. This conversion resulted in increased costs of several hundred million dollars annually. These costs can be reduced by relaxing kerosene jet fuel properties, using cracked stocks and/or considering the greater volumetric energy content of kerosene jet fuel

Riddled-like Basin in Two-Dimensional Map for Bouncing Motion of an Inelastic Particle on a Vibrating Board

Motivated by bouncing motion of an inelastic particle on a vibrating board, a simple two-dimensional map is constructed and its behavior is studied numerically. In addition to the typical route to chaos through a periodic doubling bifurcation, we found peculiar behavior in the parameter region where two stable periodic attractors coexist. A typical orbit in the region goes through chaotic motion for an extended transient period before it converges into one of the two periodic attractors. The basin structure in this parameter region is almost riddling and the fractal dimension of the basin boundary is close to two, {\it i.e.}, the dimension of the phase space.Comment: 4 pages, 5 figures. to be published in J. Phys. Soc. Jpn. (2002

Perinatal neurosteroid levels influence GABAergic interneuron localization in adult rat prefrontal cortex

Neurosteroids are a class of steroids synthesized de novo in the brain, several of which are potent modulators of GABAA receptor function. In developing brain GABAA receptor, stimulation plays a trophic role. Cortical levels of the GABAergic neurosteroid 3α-hydroxy-5α-pregnan-20-one (3α,5α-THP) vary dramatically across development; during the second week of life, elevated levels of 3α,5α-THP are associated with decreased GABAA receptor function. To determine whether alteration of endogenous 3α,5α-THP levels during development alters GABAergic interneurons in prefrontal cortex (PFC) at maturity, rat pups were exposed to 3α,5α-THP (10 mg/kg) on postnatal day 1 (P1), P2, and P5. On P80, frontal cortex tissue was assayed for GABAergic cell localization (parvalbumin and calbindin immunoreactivity), agonist-dependent [3H] dizocilpine (MK-801) binding to NMDA receptors in cortical homogenates, muscimol-mediated 36Cl- influx into synaptoneurosomes, and 3α,5α-THP levels. The localization of parvalbumin-labeled cells was markedly altered; the ratio of cell number in the deep layers (V-VI) versus superficial layers (I-III) of adult PFC increased twofold in animals exposed to 3α,5α-THP on P1 or P5. Relative microtubule-associated protein-2 and calbindin immunoreactivity were not altered by perinatal 3α,5α-THP administration. Agonist-dependent [3H]MK-801 binding was decreased in PFC but not parietal cortex homogenates, whereas muscimolmediated 36Cl- influx and 3α,5α-THP levels were unchanged in frontal cortex of adult males exposed to 3α,5α-THP on P5. These data are consistent with a change in the distribution of a subset of interneurons in response to neurosteroid exposure and suggest that GABAergic neurosteroids are critical for normal development of GABAergic systems in the PFC

Magpie: towards a semantic web browser

Web browsing involves two tasks: finding the right web page and then making sense of its content. So far, research has focused on supporting the task of finding web resources through ‘standard’ information retrieval mechanisms, or semantics-enhanced search. Much less attention has been paid to the second problem. In this paper we describe Magpie, a tool which supports the interpretation of web pages. Magpie offers complementary knowledge sources, which a reader can call upon to quickly gain access to any background knowledge relevant to a web resource. Magpie automatically associates an ontologybased semantic layer to web resources, allowing relevant services to be invoked within a standard web browser. Hence, Magpie may be seen as a step towards a semantic web browser. The functionality of Magpie is illustrated using examples of how it has been integrated with our lab’s web resources