Daze fasteners

A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces has line element extensions that pass through a common point

Cryogenic Insulation System

This invention relates to reusable, low density, high temperature cryogenic foam insulation systems and the process for their manufacture. A pacing technology for liquid hydrogen fueled, high speed aircraft is the development of a fully reusable, flight weight cryogenic insulation system for propellant tank structures. In the invention cryogenic foam insulation is adhesively bonded to the outer wall of the fuel tank structure. The cryogenic insulation consists of square sheets fabricated from an array of abutting square blocks. Each block consists of a sheet of glass cloth adhesively bonded between two layers of polymethacrylimide foam. Each block is wrapped in a vapor impermeable membrane, such as Kapton(R) aluminum Kapton(R), to provide a vapor barrier. Very beneficial results can be obtained by employing the present invention in conjunction with fibrous insulation and an outer aeroshell, a hot fuselage structure with an internal thermal protection system

Real Estate Income and Value Cycles: A Model of Market Dynamics

We develop a theoretical real estate cycles model linking economic fundamentals to real estate income and value. We estimate and test an econometric model specification, based on the theoretical model, using MSA level data for twenty office markets in the United States. Our major conclusion is that cities that exhibit seemingly different cyclical office market behavior may be statistically characterized by our three-parameter econometric specification. The parameters are MSA-specific amplitude, through the CAP rate, cycle duration (peak-to-peak), via the rate of partial adjustments to changing expectations about stabilized NOI and the market trend.

Haemophilus influenzae and smoking-related obstructive airways disease

Background: Intralumenal bacteria play a critical role in the pathogenesis of acute infective episodes and airway inflammation. Antigens from colonizing bacteria such as nontypeable Haemophilus influenzae (NTHi) may contribute to chronic lung disease through an immediate hypersensitivity response. The objective of this study was to determine the presence of specific NTHi-IgE antibodies in subjects with chronic bronchitis (CB) and COPD who had smoked. Methods: Serum, sputum, and saliva samples were collected from subjects with CB and moderate–severe COPD and healthy aged-matched controls. Total IgE and specific NTHi IgE were measured by enzyme linked immmunosorbent assay. Throat swabs were examined for the presence of NTHi. Results: The results demonstrate that: i) specific NTHi IgE antibodies occur at a low level in healthy subjects; ii) those with both CB and moderate–severe COPD have elevated specific NTHi IgE antibody compared with healthy controls, with higher levels in those with most severe disease; iii) IgE levels are greater in those with moderate–severe COPD than in those with CB. They demonstrate specific NTHi IgE antibody is regularly found at higher than normal levels in COPD. Conclusion: The detection of IgE antibody to colonizing bacteria in all subjects with CB or moderate–severe COPD identifies a possible mechanism of bronchospasm in these subjects amenable to specific intervention therapy

Muscle cooling: too much of a good thing?

It is well documented that strenuous exercise elicits stress on the body, which may lead to physiological impairments and associated reductions in muscle function and fatigue, in the hours and days post-exercise. Whilst fatigue is specific to the mode, intensity and duration of exercise, a failure in any of the related neural, metabolic or mechanical processes may hinder subsequent athletic performance, particularly when insufficient restoration periods are provided. This has led to significant interest in recovery strategies to ameliorate post-exercise fatigue and to optimize an athlete’s physical capabilities

2-D Circulation Control Airfoil Benchmark Experiments Intended for CFD Code Validation

A current NASA Research Announcement (NRA) project being conducted by Georgia Tech Research Institute (GTRI) personnel and NASA collaborators includes the development of Circulation Control (CC) blown airfoils to improve subsonic aircraft high-lift and cruise performance. The emphasis of this program is the development of CC active flow control concepts for both high-lift augmentation, drag control, and cruise efficiency. A collaboration in this project includes work by NASA research engineers, whereas CFD validation and flow physics experimental research are part of NASA s systematic approach to developing design and optimization tools for CC applications to fixed-wing aircraft. The design space for CESTOL type aircraft is focusing on geometries that depend on advanced flow control technologies that include Circulation Control aerodynamics. The ability to consistently predict advanced aircraft performance requires improvements in design tools to include these advanced concepts. Validation of these tools will be based on experimental methods applied to complex flows that go beyond conventional aircraft modeling techniques. This paper focuses on recent/ongoing benchmark high-lift experiments and CFD efforts intended to provide 2-D CFD validation data sets related to NASA s Cruise Efficient Short Take Off and Landing (CESTOL) study. Both the experimental data and related CFD predictions are discussed

An Examination of Performance of First Year Students at an Ontario University: An Admission Perspective

Major changes in the Ontario secondary school system over the last 15 years have increased the concerns within some universities about the use of Grade 13 marks as the principal criterion for evaluating applicants. These concerns focus on grade inflation, variability of marks among schools, and how appropriate some subjects are for university admission. This paper reports on a study of these issues conducted at McMaster University. The relationship between Grade 13 admission and Year I university averages was examined. Two issues that have received little attention elsewhere were also examined: how Year I performance varied by applicant status, and the relationship between individual Grade 13 subjects and Year I performance. The results indicate that Grade 13 marks, which are the only measure of a student's achievement available, continue to be a reasonable predictor of subsequent performance in Year I. Grade 13 subjects were identified that were more consistently associated with Year I performance than others. There was also evidence that some Grade 13 subjects may be contributing to an "inflated" admission average. The results of this study should be useful in evaluating existing admission policies and in the development of the new Ontario Academic Courses.Au cours des 15 dernières années, de sérieux changements dans le système des écoles secondaires de l'Ontario ont ajouté à l'inquiétude qui règne au sein de certaines universités face à l'emploi des notes de la 13e année comme critère principal d'évaluation des candidats universitaires. Ces craintes se centrent sur des notes "gonflées", sur une notation variable d'école en école et sur la pertinence de certains cours à l'entrée universitaire. Ce papier traite d'une étude à ce sujet, menée à l'université McMaster, qui visait à percevoir les rapports entre la moyenne d'admission de la 13e année et celle de la lere année universitaire. L'étude porta également sur l'écart entre la performance universitaire et le statut du candidat et sur la performance universitaire reliée à certaines matières de la 13e année, deux questions qui avaient suscité jusqu 'ici peu d'intérêt. Les résultats de cette étude indiquent que les notes de la 13e année, qui sont le seul système de mesure actuel du rendement scolaire, n'en demeurent pas moins un indice valide de la performance post-secondaire. Dans ce rapport, certaines matières de 13e année furent identifiées et étroite-ment associées au succès universitaire. Les découvertes signalèrent également un rapport probable entre certains sujets de 13e année et la hausse dans la moyenne d'admission. Toutes ces données devraient servira évaluer les procédures actuelles d'admission et servir à la mise sur pied de nouveaux 'cours pré-universitaires'