Leeward centerline and side fuselage entry heating predictions for the space shuttle orbiter

Heat transfer data measured along the leeward centerline and on the side fuselage of the Space Shuttle orbiter during STS-2 and STS-3 are compared with predictions of empirical heating techniques derived from wind tunnel tests. Steps required to extrapolate an existing leeward centerline theory to flight conditions are described. Generally favorable comparisons from Mach 24 down to approximately Mach 7 for both flights are presented. The side fuselage impingement heating method is currently under development, but some preliminary results are available. The method is briefly described and compared with wind tunnel and flight measurements. Side heating predictions are given for an STS-3 trajectory point near Mach 10 showing good agreement with flight data. There is evidence of embedded vortices emanating from the side fuselage impingement line which significantly enhance local heating rates at both wind tunnel and flight conditions

Flow-field surveys on the windward side of the NASA 040A space shuttle orbiter at 31 deg angle of attack and Mach 20 in helium

Pitot pressure and flow angle distributions in the windward flow field of the NASA 040A space shuttle orbiter configuration and surface pressures were measured, at a Mach number of 20 and an angle of attack of 31 deg. The free stream Reynolds number, based on model length, was 5.39 x 10 to the 6th power. Results show that cores of high pitot pressure, which are related to the body-shock-wing-shock intersections, occur on the windward plane of symmetry in the vicinity of the wing-body junction and near midspan on the wing. Theoretical estimates of the flow field pitot pressures show that conical flow values for the windward plane of symmetry surface are representative of the average level over the entire lower surface

Teachers' sense of their professional identity

Abstract The overall aim of this dissertation was to contribute to the conceptualization of teachers’ professional identity. Based on the literature and previous research, teachers’ job satisfaction, self-efficacy, occupational commitment, and change in level of motivation were perceived as indicators of teachers’ sense of their professional identity. The relationships between these indicators were explored using data of 1214 teachers working in secondary education in the Netherlands. Teachers’ relationship satisfaction (referring, for instance, to teachers’ satisfaction with the support they receive or their satisfaction with their co-workers) and teachers’ classroom self-efficacy play a pivotal role in the relationships between the indicators. By further analysing the same dataset, three distinct professional identity profiles were identified: an unsatisfied and demotivated identity profile consisting of teachers who scored relatively low on the indicators, a motivated and affectively committed identity profile consisting of teachers who scored relatively high on the indicators, and a competence doubting identity profile consisting of teachers with a more diverse score pattern. Differences between the profiles were observed regarding teachers’ beliefs about the objectives of education: ‘stimulating personal and moral development’ and ‘importance of qualification and schooling’. No differences between the profiles were observed regarding the teachers’ amount of experience. An additional exploratory study among eighteen teachers showed that the students of teachers with an unsatisfied and demotivated identity profile observed their teachers’ behaviours ‘providing clear instruction’ and ‘efficient classroom management’ more often than students’ ratings of teachers with a motivated and affectively committed or a competence doubting identity profile. Samenvatting De professionele identiteit van docenten moet gezien worden als het resultaat van de voortdurende interactie tussen de persoonlijke kenmerken van een docent en de kenmerken van diens werkomgeving. Deze voortdurende interactie wordt weerspiegeld in de motivatie, het vertrouwen in het eigen kunnen, de arbeidssatisfactie en de professionele betrokkenheid van de docent. De relaties tussen deze indicatoren zijn onderzocht met behulp van gegevens van 1214 leerkrachten in het voortgezet onderwijs in Nederland. De tevredenheid met de contacten op het werk (verwijzend naar, bijvoorbeeld, de tevredenheid met de ontvangen ondersteuning) en het vertrouwen in het eigen kunnen in de klas spelen een centrale rol in de relaties tussen de indicatoren. Op basis van dezelfde dataset werden drie verschillende professionele identiteitsprofielen onderscheidden: een unsatisfied and demotivated profiel, (docenten met dit profiel scoren relatief laag op de indicatoren), een motivated and affectively committed profiel (docenten met dit profiel scoren relatief hoog op de indicatoren) en een competence doubting profiel (bestaande uit docenten met een divers score patroon). Verschillen tussen de profielen werden waargenomen ten aanzien van opvattingen over de doelstellingen van het onderwijs: ‘bevordering van de persoonlijke en morele ontwikkeling’ en ‘belang van kwalificatie en scholing’. De docenten behorende tot de drie profielen verschilden niet in hun hoeveelheid ervaring in het onderwijs. Uit een extra verkennende studie onder achttien leraren bleek dat de leerlingen van de leerkrachten met een unsatisfied and demotivated profiel vaker het gedrag ‘duidelijke instructie’ en ‘efficiënt klasmanagement’ waarnamen bij hun docent dan leerlingen van leerkrachten met een ander identiteitsprofiel.

Stochastic thermodynamic bounds on logical circuit operation

Using a thermodynamically consistent, mesoscopic model for modern complementary metal-oxide-semiconductor transistors, we study an array of logical circuits and explore how their function is constrained by recent thermodynamic uncertainty relations when operating near thermal energies. For a single NOT gate, we find operating direction-dependent dynamics, and an optimal trade-off between dissipated heat and operation time certainty. For a memory storage device, we find an exponential relationship between the memory retention time and energy required to sustain that memory state. For a clock, we find that the certainty in the cycle time is maximized at biasing voltages near thermal energy, as is the trade-off between this certainty and the heat dissipated per cycle. We demonstrate that a simple control mechanism for the clock leads to a monotonic increase in cycle time certainty with biasing voltage alleviating its degradation at large biasing voltages. These results provide a framework for assessing thermodynamic costs of realistic computing devices, allowing for circuits to be designed and controlled for thermodynamically optimal operation.Comment: 6 pages, 3 figure

Heat transfer and oil flow studies on a single-stage-to-orbit control-configured winged entry vehicle

Results are presented for oil flow and phase change paint heat transfer tests conducted on a 0.006 scale model of a proposed single stage to orbit control configured vehicle. The data were taken at angles of attack up to 40 deg at a free stream Mach number of 10 for Reynolds numbers based on model length of 0.5 x 10 to the 6th power, 1.0 x 10 to the 6th power and 2.0 x 10 to the 6th power. The magnitude and distribution of heating are characterized in terms of angle of attack and Reynolds number aided by an analysis of the flow data which are used to suggest the presence of various three dimensional flow structures that produce the observed heating patterns. Of particular interest are streak heating patterns that result in high localized heat transfer rates on the wing windward surface at low to moderate angles of attack. These streaks are caused by the bow-shock/wing-shock interaction and formation of the wing-shock. Embedded vorticity was found to be associated with these interactions

Pets in Print Advertising - Are We Seeing More of Rover and Fluffy? A Content Analysis of Four Popular Magazines

This content analysis of advertising in four popular magazines investigates whether the role of pets-specifically dogs and cats-has changed as they have grown in popularity and power in American culture. Analysis of print advertisements from 1994 and 2004 suggests that although the frequency with which household pets appear in print advertisements has declined slightly, portrayals of Rover and Fluffy have changed to reflect society\u27s growing fascination with and devotion to our furry family members

Bionomics of Insects Associated with Corn in the Nebraska Sandhills

Investigations were conducted in the Nebraska Sandhills to determine the impact of transition from grassland to irrigated corn on selected insect species, to identify indigenous species that may be economically important to corn production, and to provide a point of reference for future development of pest management programs for irrigated corn

Response of selected microorganisms to experimental planetary environments

The anaerobic utilization of phosphite or phosphine and the significance of this conversion to potential contamination of Jupiter were investigated. A sporeforming organism was isolated from Cape Canaveral soil which anaerobically converts hypophosphite to phosphate. This conversion coincides with an increase in turbidity of the culture and with phosphate accumulation in the medium. Investigations of omnitherms (organisms which grow over a broad temperature range, i.e. 3 -55 C were also conducted. The cellular morphology of 28 of these isolates was investigated, and all were demonstrated to be sporeformers. Biochemical characterizations are also presented. Procedures for replicate plating were evaluated, and those results are also presented. The procedures for different replicate-plating techniques are presented, and these are evaluated on the basis of reproducibility, percentage of viable transfer, and ease of use. Standardized procedures for the enumeration of microbial populations from ocean-dredge samples from Cape Canaveral are also presented

Erythrocytes and Vascular Function: Oxygen and Nitric Oxide

Erythrocytes regulate vascular function through the modulation of oxygen delivery and the scavenging and generation of nitric oxide (NO). First, hemoglobin inside the red blood cell binds oxygen in the lungs and delivers it to tissues throughout the body in an allosterically regulated process, modulated by oxygen, carbon dioxide and proton concentrations. The vasculature responds to low oxygen tensions through vasodilation, further recruiting blood flow and oxygen carrying erythrocytes. Research has shown multiple mechanisms are at play in this classical hypoxic vasodilatory response, with a potential role of red cell derived vasodilatory molecules, such as nitrite derived nitric oxide and red blood cell ATP, considered in the last 20 years. According to these hypotheses, red blood cells release vasodilatory molecules under low oxygen pressures. Candidate molecules released by erythrocytes and responsible for hypoxic vasodilation are nitric oxide, adenosine triphosphate and S-nitrosothiols. Our research group has characterized the biochemistry and physiological effects of the electron and proton transfer reactions from hemoglobin and other ferrous heme globins with nitrite to form NO. In addition to NO generation from nitrite during deoxygenation, hemoglobin has a high affinity for NO. Scavenging of NO by hemoglobin can cause vasoconstriction, which is greatly enhanced by cell free hemoglobin outside of the red cell. Therefore, compartmentalization of hemoglobin inside red blood cells and localization of red blood cells in the blood stream are important for healthy vascular function. Conditions where erythrocyte lysis leads to cell free hemoglobin or where erythrocytes adhere to the endothelium can result in hypertension and vaso constriction. These studies support a model where hemoglobin serves as an oxido-reductase, inhibiting NO and promoting higher vessel tone when oxygenated and reducing nitrite to form NO and vasodilate when deoxygenated. How erythrocytes modulate vascular tone has been widely studied over the last two decades. The vasodilation of the vasculature under hypoxic conditions has inspired much research ranging from the effect of oxygen partial pressure on smooth muscle cell contractility and endothelial nitric oxide synthase (eNOS) activity to nitrite reduction by hemoglobin (Hb) inside erythrocytes and subsequent production of nitric oxide. Here we review how red blood cells (RBCs) and hemoglobin regulate vascular function and blood flow