461 research outputs found

    Advanced crew procedures development techniques: Procedures and performance program training plan

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    A plan developed to support the training of PPP users in the operations associated with PPP usage is described. This document contains an overview of the contents of each training session and a detailed outline to be used as the guideline for each session

    Advanced crew procedures development techniques: Procedures and performance program description

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    The Procedures and Performance Program (PPP) for operation in conjunction with the Shuttle Procedures Simulator (SPS) is described. The PPP user interface, the SPS/PPP interface, and the PPP applications software are discussed

    PPP effectiveness study

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    This design note presents a study of the Procedures and Performance Program (PPP) effectiveness. The intent of the study is to determine manpower time savings and the improvements in job performance gained through PPP automated techniques. The discussion presents a synopsis of PPP capabilities and identifies potential users and associated applications, PPP effectiveness, and PPP applications to other simulation/training facilities. Appendix A provides a detailed description of each PPP capability

    PPP/nonreal-time trajectory program interface requirements and capabilities

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    The selection process for interfacing a nonreal time trajectory program with the procedures and performance program is outlined; the interface provides summary data timelines for any desired trajectory profile. Consideration was given to two separate digital programs for satisfying capabilities. One was the CDC 6400 digital program BANDITO, and the second was the UNIVAC 1110 SVDS program

    Digital Offset Calibration of an OPAMP Towards Improving Static Parameters of 90 nm CMOS DAC

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    In this paper, an on-chip self-calibrated 8-bit R-2R digital-to-analog converter (DAC) based on digitally compensated input offset of the operational amplifier (OPAMP) is presented. To improve the overall DAC performance, a digital offset cancellation method was used to compensate deviations in the input offset voltage of the OPAMP caused by process variations. The whole DAC as well as offset compensation circuitry were designed in a standard 90 nm CMOS process. The achieved results show that after the self-calibration process, the improvement of 48% in the value of DAC offset error is achieved

    Lithographic band gap tuning in photonic band gap crystals

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    We describe the lithographic control over the spectral response of three-dimensional photonic crystals. By precise microfabrication of the geometry using a reproducible and reliable procedure consisting of electron beam lithography followed by dry etching, we have shifted the conduction band of crystals within the near-infrared. Such microfabrication has enabled us to reproducibly define photonic crystals with lattice parameters ranging from 650 to 730 nm. In GaAs semiconductor wafers, these can serve as high-reflectivity (> 95%) mirrors. Here, we show the procedure used to generate these photonic crystals and describe the geometry dependence of their spectral response

    Independent Orbiter Assessment (IOA): Analysis of the life support and airlock support subsystems

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    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Life Support System (LSS) and Airlock Support System (ALSS). Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode. The LSS provides for the management of the supply water, collection of metabolic waste, management of waste water, smoke detection, and fire suppression. The ALSS provides water, oxygen, and electricity to support an extravehicular activity in the airlock

    Advance crew procedures development techniques: Procedures generation program requirements document

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    The Procedures Generation Program (PGP) is described as an automated crew procedures generation and performance monitoring system. Computer software requirements to be implemented in PGP for the Advanced Crew Procedures Development Techniques are outlined

    Cell Signaling and Stress Response in the Yeast Saccharomyces cerevisiae: A study of SNF1

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    Saccharomyces cerevisiae are yeast that are unicellular eukaryotic organisms that are well studied as a model organism for understanding fundamental cellular processes. The ability of yeast to sense nutrient availability is crucial for their survival, growth, and reproduction. Yeast cells use various mechanisms to sense and respond to nutrient availability, including transporter-mediated uptake, receptor-mediated signaling, and sensing of metabolites. The subcellular localization of nutrient-sensing components is crucial for yeast function in nutrient sensing and signaling. Protein complexes, such as the AMP-activated protein kinase (AMPK) pathway, in nutrient sensing and response, as well as the downstream effects of these pathways on yeast metabolism and physiology, are vital. This information is critical to understanding cellular homeostasis mechanisms and may provide insights into the origins of diseases such as cancer, diabetes, and cardiomyopathy. Yeast can utilize various carbon sources for energy and biomass synthesis, and regulating this process involves multiple signaling pathways, transcriptional networks, and post-translational modifications. Glucose is the preferred carbon source, and its utilization is regulated by the Ras/cAMP/PKA, Snf1/AMPK, and TOR pathways. Other environmental factors, including pH, temperature, and oxygen availability, also influence carbon source utilization in yeast. Understanding the molecular mechanisms involved in yeast carbon source regulation is crucial for developing new biotechnological applications. Additionally, this thesis aims to elucidate the potential effects of various stressors, including caffeine, hydroxyurea, cycloheximide, camptothecin, NaCl, ethanol, and hydrogen peroxide, on yeast growth in mutants lacking different isozymes of SNF1 and its USAKs, which are poorly characterized for non-carbon source-related stressors. This research will provide insight into the role of SNF1 and its USAKs in stress response and cell growth
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