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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Initial Results from the High Fluence UCSB ATR-2 Irradiation

A primary focus of the Department of Energy, Office of Nuclear Energy Light Water Reactor Sustainability Program (LWRSP) is the safe operation of nuclear reactors to extended lifetimes of up to 80 years. One of the primary reactor components of concern is the reactor pressure vessel (RPV), which is increasingly embrittled over time due to damage from high energy neutrons created in the reactor core. Radiation damage leads to the formation of nm-scale precipitates and solute-defect clusters, which result in an increase in the steel's ductile to brittle transition temperature. Transition temperature shifts (TTS) are used to quantify and regulate embrittlement. Extended life operation will subject some RPVs to higher neutron fluences than previously experienced by in-service vessels. Thus, robust prediction methods must be developed that ensure the safety of our nation's fleet of reactors. Current models underpredict embrittlement data from high flux test reactor irradiations at extended life fluences. It has been hypothesized that one reason for this underprediction is the formation of so-called 'Late- Blooming Phase' Mn-Ni-Si precipitates, which form and grow only at high fluence and that are currently not included in regulatory models. Recent research has demonstrated the existence of high volume fractions of intermetallic Mn-Ni-Si precipitate (MNSP) phases at high fluence and have generated significant insight into their character. However, a number of questions remain regarding MNSPs, such as: 1) what alloys are most susceptible to MNSP formation; 2) how is MNSP formation affected by flux (φ), fluence (φt) and irradiation temperature (T{sub irr}); and, 3) how to accurately predict TTS under extended life low flux service conditions? The fact that no two RPVs are exactly the same, both in terms of the steel composition and vessel service conditions, makes these questions particularly difficult to answer. Further, understanding the effect of flux differences between test reactor irradiations and in-vessel service is absolutely critical. Hence, physical models must be developed that predict TTS as a function of alloy solute content and vessel service conditions. A large-scale irradiation designed to develop and validate an extended life embrittlement prediction model was recently completed in the Advanced Test Reactor (ATR) at the Idaho National Laboratory as part of the DOE sponsored Nuclear Scientific User Facilities. This experiment, called the UCSB ATR-2 irradiation, is a collaboration between Oak Ridge National Lab (ORNL) and the University of California, Santa Barbara (UCSB) and is now primarily supported by the DOE Light Water Reactor Sustainability Program. The experiment is designed to investigate the single and combined effects of neutron φ, φt, T{sub irr} and alloy chemistry on precipitate formation, hardening and embrittlement. While postirradiation examinations (PIE) is ongoing, and is expected to take several years to complete, the first preliminary results are presented below. It should also be noted that Rolls-Royce has been a collaborator in UCSB ATR-2 from the start, and there are several other national and international institutions supporting the PIE. (authors)

36 MATERIALS SCIENCE↗
NASA NTRS1988

Angiotensin converting enzyme inhibition and the kidney

Angiotensin II (Ang II) induces a marked reduction in renal blood flow at doses well below those required to induce a pressor response, and as blood flow falls there is a decline in glomerular filtration rate and sodium excretion. This striking sensitivity of the renal blood supply led many workers to consider the possibility that angiotensin functions as a local renal hormone. As angiotensin converting enzyme (ACE) was found in particular abundance in the lung, it seemed reasonable to suspect that most of the conversion occurred there, and that the function of Ang II would be primarily systemic, rather than intrarenal. In this review, I will explore the evidence that has accumulated on these two possibilities, since they have important implications for our current understanding of normal kidney function and derangements of kidney function in disease.

NASA Program Biomedical Research↗
NASA NTRS2010

Slice-Based Formal Specification Measures -- Mapping Coupling and Cohesion Measures to Formal Z

This paper demonstrates that existing slice-based measures can reasonably be mapped to the field of state-based specification languages. By making use of Z specifications this contribution renews the idea of slice-profiles and derives coupling and cohesion measures for them. The measures are then assessed by taking a critical look at their sensitiveness in respect to modifications on the specification source. The presented study shows that slice-based coupling and cohesion measures have the potential to be used as quality indicators for specifications as they reflect the changes in the structure of a specification as accustomed from their program-related pendants.

Bollin, Andreas↗
NASA NTRS2000

Space Medicine

The National Academy of Sciences Committee on Space Biology and Medicine points out that space medicine is unique among space sciences, because in addition to addressing questions of fundamental scientific interest, it must address clinical or human health and safety issues as well. Efforts to identify how microgravity affects human physiology began in earnest by the United States in 1960 with the establishment of the National Aeronautics and Space Administration (NASA's) Life Sciences program. Before the first human space missions, prediction about the physiological effects of microgravity in space ranged from extremely severe to none at all. The understanding that has developed from our experiences in space to date allows us to be guardedly optimistic about the ultimate accommodations of humans to space flight. Only by our travels into the microgravity environment of space have we begun to unravel the mysteries associated with gravity's role in shaping human physiology. Space medicine is still at its very earliest stages. Development of this field has been slow for several reasons, including the limited number of space flights, the small number of research subjects, and the competition within the life sciences community and other disciplines for flight opportunities. The physiological changes incurred during space flight may have a dramatic effect on the course of an injury or illness. These physiological changes present an exciting challenge for the field of space medicine: how to best preserve human health and safety while simultaneously deciphering the effects of microgravity on human performance. As the United States considers the future of humans in long-term space travel, it is essential that the many mysteries as to how microgravity affects human systems be addressed with vigor. Based on the current state of our knowledge, the justification is excellent indeed compelling- for NASA to develop a sophisticated capability in space medicine. Teams of physicians and scientists should be actively engaged in fundamental and applied research designed to ensure that it is safe for humans to routinely and repeatedly stay and work in the microgravity environment of space.

Pool, Sam L.↗
NASA NTRS2016

Humans vs Hardware: The Unique World of NASA Human System Risk Assessment

Understanding spaceflight risks to crew health and performance is a crucial aspect of preparing for exploration missions in the future. The research activities of the Human Research Program (HRP) provide substantial evidence to support most risk reduction work. The Human System Risk Board (HSRB), acting on behalf of the Office of Chief Health and Medical Officer (OCHMO), assesses these risks and assigns likelihood and consequence ratings to track progress. Unfortunately, many traditional approaches in risk assessment such as those used in the engineering aspects of spaceflight are difficult to apply to human system risks. This presentation discusses the unique aspects of risk assessment from the human system risk perspective and how these limitations are accommodated and addressed in order to ensure that reasonable inputs are provided to support the OCHMO's overall risk posture for manned exploration missions.

Anton, W.↗
NASA NTRS2017

Medical Optimization Network for Space Telemedicine Resources

INTRODUCTION: Long-duration missions beyond low Earth orbit introduce new constraints to the space medical system. Beyond the traditional limitations in mass, power, and volume, consideration must be given to other factors such as the inability to evacuate to Earth, communication delays, and limitations in clinical skillsets. As NASA develops the medical system for an exploration mission, it must have an ability to evaluate the trade space of what resources will be most important. The Medical Optimization Network for Space Telemedicine Resources (MONSTR) was developed over the past year for this reason, and is now a system for managing data pertaining to medical resources and their relative importance when addressing medical conditions. METHODS: The MONSTR web application with a Microsoft SQL database backend was developed and made accessible to Tableau v9.3 for analysis and visualization. The database was initially populated with a list of medical conditions of concern for an exploration mission taken from the Integrated Medical Model (IMM), a probabilistic model designed to quantify in-flight medical risk. A team of physicians working within the Exploration Medical Capability Element of NASA's Human Research Program compiled a list diagnostic and treatment medical resources required to address best- and worst-case scenarios of each medical condition using a terrestrial standard of care and entered this data into the system. This list included both tangible resources (e.g. medical equipment, medications) and intangible resources (e.g. clinical skills required to perform a procedure). The physician team then assigned criticality values to each instance of a resource, representing the importance of that resource to diagnosing or treating its associated condition(s). Medical condition probabilities of occurrence during a Mars mission were pulled from the IMM and imported into the MONSTR database for use within a resource criticality-weighting algorithm. DISCUSSION: The MONSTR tool is a novel approach to assess the relative value of individual resources needed for the diagnosis and treatment of medical conditions. Future work will add resources for prevention and long term care of these conditions. Once data collection is complete, MONSTR will provide the operational and research communities at NASA with information to support informed decisions regarding areas of research investment, future crew training, and medical supplies manifested as part of any exploration medical system.

Rubin, D.↗
NASA NTRS1976

Transient excitation and data processing techniques employing the fast fourier transform for aeroelastic testing

The development of testing techniques useful in airplane ground resonance testing, wind tunnel aeroelastic model testing, and airplane flight flutter testing is presented. Included is the consideration of impulsive excitation, steady-state sinusoidal excitation, and random and pseudorandom excitation. Reasons for the selection of fast sine sweeps for transient excitation are given. The use of the fast fourier transform dynamic analyzer (HP-5451B) is presented, together with a curve fitting data process in the Laplace domain to experimentally evaluate values of generalized mass, model frequencies, dampings, and mode shapes. The effects of poor signal to noise ratios due to turbulence creating data variance are discussed. Data manipulation techniques used to overcome variance problems are also included. The experience is described that was gained by using these techniques since the early stages of the SST program. Data measured during 747 flight flutter tests, and SST, YC-14, and 727 empennage flutter model tests are included.

Jennings, W. P.↗
NASA NTRS1984

Tension waves in tethered satellite cables

A one-degree-of-freedom simulation of the Tethered Satellite System (TSS) was programmed using a distributed system model of the tether based on the one-dimensional wave equation. This model represents the time varying tension profile along the tether as the sum of two traveling waves of tension moving in opposite directions. A control loop was devised which combines a deployment rate command with the measured tension at the deployer to produce a smooth, stable rate of deployment of the subsatellite. Simulation results show a buildup of periodic bursts of high frequency oscillation in tension. This report covers the mathematical modelling and simulation results and explains the reason for the observed oscillations. The design of a possible vibration damping device is discussed.

Lallman, F. J.↗
NASA NTRS1985

The role of service areas in the optimization of FSS orbital and frequency assignments

A relationship is derived, on a single-entry interference basis, for the minimum allowable spacing between two satellites as a function of electrical parameters and service-area geometries. For circular beams, universal curves relate the topocentric satellite spacing angle to the service-area separation angle measured at the satellite. The corresponding geocentric spacing depends only weakly on the mean longitude of the two satellites, and this is true also for alliptical antenna beams. As a consequence, if frequency channels are preassigned, the orbital assignment synthesis of a satellite system can be formulated as a mixed-integer programming (MIP) problem or approximated by a linear programming (LP) problem, with the interference protection requirements enforced by constraints while some linear function is optimized. Possible objective-function choices are discussed and explicit formulations are presented for the choice of the sum of the absolute deviations of the orbital locations from some prescribed ideal location set. A test problem is posed consisting of six service areas, each served by one satellite, all using elliptical antenna beams and the same frequency channels. Numerical results are given for the three ideal location prescriptions for both the MIP and LP formulations. The resulting scenarios also satisfy reasonable aggregate interference protection requirements.

Levis, C. A.↗
NASA NTRS1987

Advanced photovoltaic solar array design assessment

The Advanced Photovoltaic Solar Array (APSA) program seeks to bring to flight readiness a solar array that effectively doubles the specific power of the Solar Array Flight Experiment/Solar Electric Propulsion (SAFE/SEP) design that was successfully demonstrated during the Shuttle 41-D mission. APSA is a critical intermediate milestone in the effort to demonstrate solar array technologies capable of 300 W/kg and 300 W/square m at beginning of life (BOL). It is not unreasonable to anticipate the development of solar array designs capable of 300 W/kg at BOL for operational power levels approx. greater than 25 kW sub e. It is also quite reasonable to expect that high performance solar arrays capable of providing at least 200 W/kg at end of life for most orbits now being considered by mission planners will be realized in the next decade.

Stella, Paul↗
NASA NTRS1993

Intelligent systems and advanced user interfaces for design, operation, and maintenance of command management systems

Historically, command management systems (CMS) have been large and expensive spacecraft-specific software systems that were costly to build, operate, and maintain. Current and emerging hardware, software, and user interface technologies may offer an opportunity to facilitate the initial formulation and design of a spacecraft-specific CMS as well as to develop a more generic CMS system. New technologies, in addition to a core CMS common to a range of spacecraft, may facilitate the training and enhance the efficiency of CMS operations. Current mission operations center (MOC) hardware and software include Unix workstations, the C/C++ programming languages, and an X window interface. This configuration provides the power and flexibility to support sophisticated and intelligent user interfaces that exploit state-of-the-art technologies in human-machine interaction, artificial intelligence, and software engineering. One of the goals of this research is to explore the extent to which technologies developed in the research laboratory can be productively applied in a complex system such as spacecraft command management. Initial examination of some of these issues in CMS design and operation suggests that application of technologies such as intelligent planning, case-based reasoning, human-machine systems design and analysis tools (e.g., operator and designer models), and human-computer interaction tools (e.g., graphics, visualization, and animation) may provide significant savings in the design, operation, and maintenance of the CMS for a specific spacecraft as well as continuity for CMS design and development across spacecraft. The first six months of this research saw a broad investigation by Georgia Tech researchers into the function, design, and operation of current and planned command management systems at Goddard Space Flight Center. As the first step, the researchers attempted to understand the current and anticipated horizons of command management systems at Goddard. Preliminary results are given on CMS commonalities and causes of low re-use, and methods are proposed to facilitate increased re-use.

Potter, William J.↗
NASA NTRS2003

Low-Energy Study of Gamma-Ray Bursts Having Spectral Line Features

Gamma-ray bursts (GRBs) are energetic, short-duration emissions of gamma-rays. The Burst and Transient Source Experiment (BATSE) that was onboard NASA s Compton Gamma-Ray Observatory has done much to advance our understanding of GRBs. Perhaps foremost is to establish that GRBs originate from astronomical sources that exist well beyond our galaxy. Another area in which BATSE has been instrumental is to provide high-resolution data that can be used in spectral studies. Before BATSE, there were many reports of GRB spectra containing what appeared to be spectral absorption lines, whereas Briggs, after an extensive computer search of 117 bright BATSE GRBs, reported finding only one case that might be an absorption line and ten cases that might be emission lines. None of the eleven BATSE cases were definitively identified as spectral lines, and Briggs indicated reasons as to why the pre-BATSE reports should not be taken as conclusive. It remains an open question as to what these spectral-like features are, or if they are even real. The purpose of this work is, for the subset of the eleven BATSE GRBs for which low-energy data are available from two BATSE's Spectroscopy Detectors (SDs), to include these data in the spectral analysis. Such a study will provide additional constraints on the model spectral functions to better ascertain the reality of the line features. The spectral analysis program used was RMFIT. Of the six GRBs that met the selection criteria, the analysis was performed on only three of them due to a lack of time.

Pangia, Michael J.↗
NASA NTRSDate not supplied

Combining Disparate Measures of Metabolic Rate During Simulated Spacewalks

Scientists from NASA's Extravehicular Activities (EVA) Physiology Systems and Performance Project help design space suits for future missions, during which astronauts are expected to perform EVA activities on the Lunar or Martian surface. During an EVA, an astronaut's integrated metabolic rate is used to predict how much longer the activity can continue and still provide a safe margin of remaining consumables. For EVAs in the Apollo era, NASA physicians monitored live data feeds of heart rate, O 2 consumption, and liquid cooled garment (LCG) temperatures, which were subjectively combined or compared to produce an estimate of metabolic rate. But these multiple data feeds sometimes provided conflicting estimates of metabolic rate, making real-time calculations of remaining time difficult for physician/monitors. Currently, designs planned for the Constellation Program EVAs utilize an automated, but largely heuristic methodology for incorporating the above three measurements, plus an additional one - CO 2 production, ignoring data that appears in conflict; however a more rigorous model-based approach is desirable. In this study, we show how principal axis factor analysis, in combination with OLS regression and LOWESS smoothing can be used to estimate metabolic rate as a data-driven weighted average of heart rate, O 2 consumption, LCG temperature data, and CO 2 production. Preliminary results suggest less sensitivity to occasional spikes in observed data feeds, and reasonable within-subject reproducibility when applied to subsequent tasks. These methods do not require physician monitoring and as such can be automated in the electronic components of future space suits. With additional validation, our models show promise for increasing astronaut safety, while reducing the need for and potential errors associated with human monitoring of multiple systems.

Alan H Feiveson↗
NASA NTRS2012

Why Games Work and the Science of Learning

In 2010, the Navy formally added the Damage Control Trainer (DCT) to the recruit training program at Great Lakes, Illinois. Despite the incredibly dense training schedule at the Navy's boot camp, the instructors were willing to set aside two hours of time for recruits to play a game. Why? Because it worked. Even with just one hour of play, research showed that recruits gained a 50-80% improvement in performance that transferred to Battle Stations 21 (B821), the Navy's capstone training event. This paper explores why games makes these kinds of results possible. It argues that the things that are known to improve learning are almost exactly the same reasons why games work: the time-honored laws of learning. It concludes that the traditional gulf between instructional design and game design is really an issue of perspective, rather than fundamentals.

Murphy, Curtiss↗
DOE OSTI2012

Current Status of the Advanced High Temperature Reactor

The Advanced High Temperature Reactor (AHTR) is a design concept for a central station type [1500 MW(e)] Fluoride salt-cooled High-temperature Reactor (FHR) that is currently under development by Oak Ridge National Laboratory for the U. S. Department of Energy, Office of Nuclear Energy's Advanced Reactor Concepts program. FHRs, by definition, feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The overall goal of the AHTR development program is to demonstrate the technical feasibility of FHRs as low-cost, large-size power producers while maintaining full passive safety. The AHTR design option exploration is a multidisciplinary design effort that combines core neutronic and fuel configuration evaluation with structural, thermal, and hydraulic analysis to produce a reactor and vessel concept and place it within a power generation station. The AHTR design remains at the notional level of maturity, as key technologies require further development and a logically complete integrated design has not been finalized. The present design space exploration, however, indicates that reasonable options exist for the AHTR core, primary heat transport path, and fuel cycle provided that materials and systems technologies develop as anticipated.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2012

Current status of the advanced high temperature reactor

The Advanced High Temperature Reactor (AHTR) is a design concept for a central station type [1500 MW(e)] Fluoride salt-cooled High-temperature Reactor (FHR) that is currently under development by Oak Ridge National Laboratory for the U. S. Dept. of Energy, Office of Nuclear Energy's Advanced Reactor Concepts program. FHRs, by definition, feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The overall goal of the AHTR development program is to demonstrate the technical feasibility of FHRs as low-cost, large-size power producers while maintaining full passive safety. The AHTR design option exploration is a multidisciplinary design effort that combines core neutronic and fuel configuration evaluation with structural, thermal, and hydraulic analysis to produce a reactor and vessel concept and place it within a power generation station. The AHTR design remains at the notional level of maturity, as key technologies require further development and a logically complete integrated design has not been finalized. The present design space exploration, however, indicates that reasonable options exist for the AHTR core, primary heat transport path, and fuel cycle provided that materials and systems technologies develop as anticipated. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2012

Physical Protection of Spent Fuel Shipments: Resolution of Stakeholder Concerns Through Rulemaking - 12284

In 1999, the State of Nevada brought its concerns about physical protection of current spent nuclear fuel (SNF) shipments, and future SNF shipments to a federal repository, before the NRC in a 1999 petition for rulemaking (PRM-73-10). In October 2010, the NRC published a rulemaking decision which would significantly strengthen physical protection of SNF in transit. The newest articulation of the rule (10 CFR 73.37) incorporates regulatory clarifications and security enhancements requested in Nevada's 1999 petition for rulemaking, codifies the findings of the Nuclear NRC and DOE consequence analyses into policy guidance documents and brings forward into regulations the agency and licensee experience gained since the terrorist attacks of September 11, 2001. Although at present DOE SNF shipments would continue to be exempt from these NRC regulations, Nevada considers the rule to constitute a largely satisfactory resolution to stakeholder concerns raised in the original petition and in subsequent comments submitted to the NRC. This paper reviews the process of regulatory changes, assesses the specific improvements contained in the new rules and briefly describes the significance of the new rule in the context of a future national nuclear waste management program. Nevada's petition for rulemaking led to a generally satisfactory resolution of the State's concerns. The decade plus timeframe from petition to rulemaking conclusion saw a sea change in many aspects of the relevant issues - perhaps most importantly the attacks on 9/11 led to the recognition by regulatory bodies that a new threat environment exists wherein shipments of SNF and HLW pose a viable target for human initiated events. The State of Nevada has always considered security a critical concern for the transport of these highly radioactive materials. This was one of the primary reasons for the original rulemaking petition and subsequent advocacy by Nevada on related issues. NRC decisions on the majority of the concerns expressed in the petition, additional developments by other regulatory bodies and the change in how the United States sees threats to the homeland - all of these produced a satisfactory resolution through the rulemaking process. While not all of the concerns expressed by Nevada were addressed in the proposed rule and significant challenges face any programmatic shipment campaign in the future, the lesson learned on this occasion is that stakeholder concerns can be resolved through rulemaking. If DOE would engage with stakeholders on its role in transport of SNF and HLW under the NWPA, these concerns would be better addressed. Specifically the attempts by DOE to resist transportation and security regulations now considered necessary by the NRC for the adequate protection of the shipments of highly radioactive materials, these DOE efforts seem ill advised. One clear lesson learned from this successful rulemaking petition process is that the system of stakeholder input can work to better the regulatory environment. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Consistent lensing and clustering in a low- S 8 Universe with BOSS, DES Year 3, HSC Year 1, and KiDS-1000

ABSTRACT We evaluate the consistency between lensing and clustering based on measurements from Baryon Oscillation Spectroscopic Survey combined with galaxy–galaxy lensing from Dark Energy Survey (DES) Year 3, Hyper Suprime-Cam Subaru Strategic Program (HSC) Year 1, and Kilo-Degree Survey (KiDS)-1000. We find good agreement between these lensing data sets. We model the observations using the Dark Emulator and fit the data at two fixed cosmologies: Planck (S8 = 0.83), and a Lensing cosmology (S8 = 0.76). For a joint analysis limited to large scales, we find that both cosmologies provide an acceptable fit to the data. Full utilization of the higher signal-to-noise small-scale measurements is hindered by uncertainty in the impact of baryon feedback and assembly bias, which we account for with a reasoned theoretical error budget. We incorporate a systematic inconsistency parameter for each redshift bin, A, that decouples the lensing and clustering. With a wide range of scales, we find different results for the consistency between the two cosmologies. Limiting the analysis to the bins for which the impact of the lens sample selection is expected to be minimal, for the Lensing cosmology, the measurements are consistent with A = 1; A = 0.91 ± 0.04 (A = 0.97 ± 0.06) using DES+KiDS (HSC). For the Planck case, we find a discrepancy: A = 0.79 ± 0.03 (A = 0.84 ± 0.05) using DES+KiDS (HSC). We demonstrate that a kinematic Sunyaev–Zeldovich-based estimate for baryonic effects alleviates some of the discrepancy in the Planck cosmology. This analysis demonstrates the statistical power of small-scale measurements; however, caution is still warranted given modelling uncertainties and foreground sample selection effects.

79 ASTRONOMY AND ASTROPHYSICS↗