A Director\u27s Process: The Conception, Preparation and Production of Chekhov\u27s Uncle Vanya

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Qualitative model-based diagnostics for rocket systems

A diagnostic software package is currently being developed at NASA LeRC that utilizes qualitative model-based reasoning techniques. These techniques can provide diagnostic information about the operational condition of the modeled rocket engine system or subsystem. The diagnostic package combines a qualitative model solver with a constraint suspension algorithm. The constraint suspension algorithm directs the solver's operation to provide valuable fault isolation information about the modeled system. A qualitative model of the Space Shuttle Main Engine's oxidizer supply components was generated. A diagnostic application based on this qualitative model was constructed to process four test cases: three numerical simulations and one actual test firing. The diagnostic tool's fault isolation output compared favorably with the input fault condition

Rocket engine diagnostics using qualitative modeling techniques

Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system was created. The qualitative model describes the effects of seal failures on the system steady state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures

Magnetic Switching of Phase-Slip Dissipation in NbSe2 Nanobelts

The stability of the superconducting dissipationless and resistive states in single-crystalline NbSe2 nanobelts is characterized by transport measurements in an external magnetic field (H). Current-driven electrical measurements show voltage steps, indicating the nucleation of phase-slip structures. Well below the critical temperature, the position of the voltage steps exhibits a sharp, periodic dependence as a function of H. This phenomenon is discussed in the context of two possible mechanisms: the interference of the order parameter and the periodic rearrangement of the vortex lattice within the nanobelt.Comment: 4 figure

Three-Dimensional Analysis of Deep Space Network Antenna Coverage

There is a need to understand NASA s Deep Space Network (DSN) coverage gaps and any limitations to provide redundant communication coverage for future deep space missions, especially for manned missions to Moon and Mars. The DSN antennas are required to provide continuous communication coverage for deep space flights, interplanetary missions, and deep space scientific observations. The DSN consists of ground antennas located at three sites: Goldstone in USA, Canberra in Australia, and Madrid in Spain. These locations are not separated by the exactly 120 degrees and some DSN antennas are located in the bowl-shaped mountainous terrain to shield against radiofrequency interference resulting in a coverage gap in the southern hemisphere for the current DSN architecture. To analyze the extent of this gap and other coverage limitations, simulations of the DSN architecture were performed. In addition to the physical properties of the DSN assets, the simulation incorporated communication forward link calculations and azimuth/elevation masks that constrain the effects of terrain for each DSN antenna. Analysis of the simulation data was performed to create coverage profiles with the receiver settings at a deep space altitudes ranging from 2 million to 10 million km and a spherical grid resolution of 0.25 degrees with respect to longitude and latitude. With the results of these simulations, two- and three-dimensional representations of the area without communication coverage and area with coverage were developed, showing the size and shape of the communication coverage gap projected in space. Also, the significance of this communication coverage gap is analyzed from the simulation data

A New Approach to Climate Change and Development: The Future of the Green Climate Fund

This report proposes that the climate crisis can be looked at as an opportunity at this time to not only curb the occurrence and effects of climate change, but to additionally address the problem of underdevelopment. The deep connections between these two problems are explored, and it is suggested that by aiming to achieve widespread clean energy access in the developing world, both adaptation and mitigation projects and the Millennium Development Goals can be pursued using the same resources. The Green Climate Fund, a financial board of the United Nations Framework Convention on Climate Change, is proposed as the mechanism through which clean energy access can be realized, utilizing a combination of technology transfer and research and development efforts. Ultimately, this proposal serves a double purpose, and does not only seek to offer a comprehensive policy approach, but to additionally reframe the debate taking place in the international arena. The report concludes by calling for a change in the way that climate change policy is configured, using the imbedded proposal as an example of where innovation in this field might move the discussion amongst international leaders

Creation of a Virtual Nutrition Support Team to Improve Quality of Care for Patients Receiving Parenteral Nutrition in a Multisite Healthcare System

Background Parenteral nutrition (PN) is a complicated therapy in which having specially trained clinicians can provide benefit, but it can be difficult to provide this level of expertise to all patients requiring PN. Creation of a virtual nutrition support team (NST) model allows patients across multiple hospitals to receive care from NST clinicians using remote conferencing technology on a daily basis. This study reviewed retrospective data from before and after implementation of the virtual model to assess quality indicators. Methods The NST was developed including a team of dietitians and pharmacists with a physician medical director. Practice guidelines were developed to provide consistent methods for ordering and monitoring patients receiving PN. Patient charts in both the preintervention and postintervention groups were reviewed for indication for PN, duration of therapy, blood glucose levels, and demographic data. Results A greater proportion of patients in the postintervention period had appropriate orders (97.2%) compared with patients in the preintervention period (58.9%) (P < 0.001). A greater proportion of patients in the postintervention period had blood glucose levels within the range 65–180 mg/dL (83.5%) compared with patients in the preintervention period (62.2%) (P < 0.001). Conclusion A virtual team model was applied to remotely manage patients receiving PN in a large healthcare system. This resulted in optimized care of patients by reducing inappropriately prescribed therapy and improving blood glucose control