The design and evolution of the beta two-stage-to-orbit horizontal takeoff and landing launch system

The Beta launch system was originally conceived in 1986 as a horizontal takeoff and landing, fully reusable, two-stage-to-orbit, manned launch vehicle to replace the Shuttle. It was to be capable of delivering a 50,000 lb. payload to low polar orbit. The booster propulsion system consisted of JP fueled turbojets and LH fueled ramjets mounted in pods in an over/under arrangement, and a single LOX/LH fueled SSME rocket. The second stage orbiter, which staged at Mach 8, was powered by an SSME rocket. A major goal was to develop a vehicle design consistent with near term technology. The vehicle design was completed with a GLOW of approximately 2,000,000 lbs. All design goals were met. Since then, interest has shifted to the 10,000 lbs. to low polar orbit payload class. The original Beta was down-sized to meet this payload class. The GLOW of the down-sized vehicle was approximately 1,000,000 lbs. The booster was converted to exclusively air-breathing operation. Because the booster depends on conventional air-breathing propulsion only, the staging Mach number was reduced to 5.5. The orbiter remains an SSME rocket-powered stage

Teacher Leader Administrators: Part 3 Of A Symposium On Teachers As Leaders

In this latest continuation of our multipart symposium on teacher leadership, we examine what happens when self-defined teacher leaders become school administrators. Do teacher leaders who become administrators maintain a teacher identity? Can they remain committed to their vision of teacher leadership when they take on the normative requirements and responsibilities of school administration? Through a conversation with three teachers leaders, we explore the rewards and trials of teaching, the choice to become teacher leaders and then administrators, and the unique challenges that face administrators who deeply value the professional, political, and collaborative work of teachers

Approximation of the acoustic radiation impedance of a cylindrical pipe

Useful approximation formulae for radiation impedance are given for the reflection coefficients of both infinitely flanged and unflanged rigid-walled cylindrical ducts. The expressions guarantee that simple but necessary physical and mathematical principles are met, like hermitian symmetry for the reflection coefficient (identical behaviour of positive and negative frequencies) and causality for the impulse response. A non causal but more accurate expression is also proposed that is suitable for frequency-domain applications. The formulae are obtained by analytical and numerical fitting to reference results from Levine & Schwinger for the unflanged case and extracted from the radiation impedance matrix given by Zorumski for the infinite flanged case.Comment: Journal of Sound and Vibration (2008) accepte

Patient Deterioration Simulation Education and New Graduate Nurses\u27 Self-Confidence and Competence

Inconsistent identification and intervention for patient deteriorations has been identified as a global healthcare issue that has a profound effect on patient outcomes. Failure to rescue (FTR) rates are influenced by the quality of care a hospital provides in the event of patient deterioration. Rapid Response Teams (RRTs) are summoned to the bedside in the event of a patient deterioration to assess the patient and intervene quickly. Efficient use of RRTs prevents cardiopulmonary arrests and decreases hospital mortality, thirty-day morality, and length of stay. Patient deterioration simulation education can improve the use of RRTs and positively influence patient outcomes. New graduate nurses and their preceptors report that new graduate nurses need additional patient deterioration education. A rural community hospital provided patient deterioration simulation education for new graduate nurses in an attempt to improve the utilization of an existing Rapid Response Team and patient outcomes by improving new graduate nurses’ self-confidence and competence. The pre- and post-intervention self-reported self-confidence scores were compared. The scores increased post-intervention, with a large effect size and a clinically significant eta squared value (.48). This pilot project supports further studies exploring new graduate nurses’ self-confidence levels with patient deterioration simulation education