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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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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Chemical constraints governing the origin of metabolism: the thermodynamic landscape of carbon group transformations under mild aqueous conditions

The thermodynamics of organic chemistry under mild aqueous conditions was examined in order to begin to understand its influence on the structure and operation of metabolism and its antecedents. Free energies (deltaG) were estimated for four types of reactions of biochemical importance carbon-carbon bond cleavage and synthesis, hydrogen transfer between carbon groups, dehydration of alcohol groups, and aldo-keto isomerization. The energies were calculated for mainly aliphatic groups composed of carbon, hydrogen, and oxygen. The energy values showed (1) that generally when carbon-carbon bond cleavage involves groups from different functional group classes (i.e., carboxylic acids, carbonyl groups, alcohols, and hydrocarbons), the transfer of the shared electron-pair to the more reduced carbon group is energetically favored over transfer to the more oxidized carbon group, and (2) that the energy of carbon-carbon bond transformation is primarily determined by the functional group class of the group that changes oxidation state in the reaction (i.e., the functional group class of the group that donates the shared electron-pair during cleavage, or that accepts the incipient shared electron-pair during synthesis). In contrast, the energy of hydrogen transfer between carbon groups is determined by the functional group class of both the hydrogen-donor group and the hydrogen-acceptor group. From these and other observations we concluded that the chemistry involved in the origin of metabolism (and to a lesser degree modern metabolism) was strongly constrained by (1) the limited redox-based transformation energy of organic substrates that is readily dissipated in a few energetically favorable irreversible reactions; (2) the energy dominance of a few transformation half-reactions that determines whether carbon-carbon bond transformation (cleavage or synthesis) is energetically favorable (deltaG < -3.5 kcal/mol), reversible (deltaG between +/-3.5 kcal/mol), or unfavorable (deltaG > +3.5 kcal/mol); and (3) the dependence of carbon group transformation energy on the functional group class (i.e., oxidation state) of participating groups that in turn is contingent on prior reactions and precursors in the synthetic pathway.

Carbon/chemistry/metabolism↗
NASA NTRS2005

Potential Interventions by Government and Industry to Minimize Violations of Temporary Flight Restrictions

This document enumerates interventions to reduce the frequency of restricted airspace violations, particularly those associated with temporary flight restrictions (TFRs) and air defense identification zones (ADIZs), by more effectively providing pilots with the information necessary to avoid such violations. Interventions are divided into both near term and far term groupings. Short term interventions, some variants of which are already in progress focus on improving the form and content of the textual Notices to Airmen (NOTAMs) as well as the graphical depiction of TFRs. A long-term technical intervention is proposed which would provide pilots the following functionality: ground and airborne presentation of information on any restricted airspace, including display on an electronic moving map, fully mechanized execution from the cockpit of the procedures required for entry into restricted airspaces that allow for entry, and alerting of the potential for TFR violations both during flight planning and while the aircraft is moving.

Zuschlag, Michael↗
NASA NTRS2007

Application of Risk within Net Present Value Calculations for Government Projects

In January 2004, President Bush announced a new vision for space exploration. This included retirement of the current Space Shuttle fleet by 2010 and the development of new set of launch vehicles. The President's vision did not include significant increases in the NASA budget, so these development programs need to be cost conscious. Current trade study procedures address factors such as performance, reliability, safety, manufacturing, maintainability, operations, and costs. It would be desirable, however, to have increased insight into the cost factors behind each of the proposed system architectures. This paper reports on a set of component trade studies completed on the upper stage engine for the new launch vehicles. Increased insight into architecture costs was developed by including a Net Present Value (NPV) method and applying a set of associated risks to the base parametric cost data. The use of the NPV method along with the risks was found to add fidelity to the trade study and provide additional information to support the selection of a more robust design architecture.

Grandl, Paul R.↗
NASA NTRS2008

How Does Mediterranean Basin's Atmosphere Become Weak Moisture Source During Negative Phase of NAO: Use of AIRS, AMSR, TOVS, & TRMM Satellite Datasets Over Last Two NAO Cycles to Examine Governing Controls on E-P

The Mediterranean Sea is a noted 'concentration" basin in that it almost continuously exhibits positive evaporation minus precipitation (E - P ) properties -- throughout the four seasons and from one year to the next. Nonetheless, according to the ECMWF Era-40 48-year (1958-2005) climate reanalysis dataset, for various phases of the North Atlantic Oscillation (NAO) when the pressure gradient between Portugal and Iceland becomes either very relaxed (large negative NAO-Index) or in transition (small positive or negative NAO-Index), the atmospheric moisture source properties of the basin become weak, at times even reversed for several months (i.e., negative E - P). This behavior poses numerous questions concerning how and why these events occur. Moreover, it begs the question of what it would take for the basin to reach its tipping point in which P would exceed E throughout the rainy season (some six months) on an annually persistent basis -- and the sea would possibly transform to a recurring "dilution" basin. This talk investigates these questions by: (1) establishing over a period from 1979 to present, based on detailed analyses of satellite retrieval products from a combination of NASA-AQUA, NOAA-LEO, NASA/JAXA Scatterometer, and NASA-TRMM platforms, plus additional specialized satellite data products and ancillary meteorological datasets, the actual observation-based behavior of E - P, (2) diagnosing the salient physical and meteorological mechanisms that lead to the weaker E - P events during the analysis period, partly based on analyzing surface and upper air data at discrete stations in the western and eastern Mediterranean -- while at the same time evaluating the quality of the ERA-40 data over this same time period, (3) conducting GCM and high-resolution regional modeling experiments to determine if perturbed but realistic meteorological background conditions could maintain Mediterranean as a "dilution" basin through the October to March rainy season on annually recurring basis, and (4) investigating how such conditions might modify important internal and external climatic processes known to be closely related to the dynamical, thermal, and hydrological properties of the basin (e.g., drought frequency over Iberian peninsula, rainfall accumulation within Sahel, alteration of Levantine branch of east-west aligned open thermohaline cell, and modification of warm-salty intermediate flow through Gibraltar straight into North Atlantic).

Smith, Eric A.↗
NASA NTRS2009

NASA's Student Launch Projects: A Government Education Program for Science and Engineering

Among the many NASA education activities, the Student Launch projects are examples of how one agency has been working with students to inspire math, science and engineering interest. There are two Student Launch projects: Student Launch Initiative (SLI) for middle and high school students and the University Student Launch Initiative (USLI) for college students. The programs are described and website links are provided for further information. This document presents an example of how an agency can work with its unique resources in partnership with schools and communities to bring excitement to the classroom.

Shepherd, Christena C.↗
NASA NTRS2009

The Governing Processes and Timescales of Stratosphere-to-Troposphere Transport and its Contribution to Ozone in the Arctic Troposphere

We used the seasonality of a combination of atmospheric trace gases and idealized tracers to examine stratosphere-to-troposphere transport and its influence on tropospheric composition in the Arctic. Maximum stratosphere-to-troposphere transport of CFCs and O3 occurs in April as driven by the Brewer-Dobson circulation. Stratosphere-troposphere exchange (STE) occurs predominantly between 40 deg N to 80 deg N with stratospheric influx in the mid-latitudes (30-70 deg N) accounting for 67.81 percent of the air of stratospheric origin in the Northern Hemisphere extratropical troposphere. Transport from the lower stratosphere to the lower troposphere (LT) takes three months on average, one month to cross the tropopause, the second month to travel from the upper troposphere (UT) to the middle troposphere (MT), and the third month to reach the LT. During downward transport, the seasonality of a trace gas can be greatly impacted by wet removal and chemistry. A comparison of idealized tracers with varying lifetimes suggests that when initialized with the same concentrations and seasonal cycles at the tropopause, trace gases that have shorter lifetimes display lower concentrations, smaller amplitudes, and earlier seasonal maxima during transport to the LT. STE contributes to O3 in the Arctic troposphere directly from the transport of O3 and indirectly from the transport of NOy . Direct transport of O3 from the stratosphere accounts for 78 percent of O3 in the Arctic UT with maximum contributions occurring from March to May. The stratospheric contribution decreases significantly in the MT/LT (20.25 percent of total O3) and shows a very weak March.April maximum. Our NOx budget analysis in the Arctic UT shows that during spring and summer, the stratospheric injection of NO y-rich air increases NOx concentrations above the 20 pptv threshold level, thereby shifting the Arctic UT from a regime of net photochemical ozone loss to one of net production with rates as high as +16 ppbv/month.

Liang, Q.↗
NASA NTRS2010

Using SCOR as a Supply Chain Management Framework for Government Agency Contract Requirements

Enterprise Supply Chain Management consists of: Specifying suppliers to support inter-program and inter-agency efforts. Optimizing inventory levels and locations throughout the supply chain. Executing corrective actions to improve quality and lead time issues throughout the supply chain. Processing reported data to calculate and make visible supply chain performance (provide information for decisions and actions). Ensuring the right hardware and information is provided at the right time and in the right place. Monitoring the industrial base while developing, producing, operating and retiring a system. Seeing performance deep in the supply chain that could indicate issues affecting system availability and readiness.

Paxton, Joe↗
NASA NTRS2010

Structured Transition of Wind Tunnel Operations Skills from Government-to Contractor-Managed

In 2004, NASA awarded the Research, Operations, Maintenance, and Engineering (ROME) contract at NASA Langley Research Center to a team led by Jacobs Technology, Inc. A key component of the contract was the transitioning of the five large wind tunnel facilities from NASA managed and NASA or NASA/contractor workforces to fully contractor operated. The contractor would manage daily operations while NASA would continue to develop long-term strategies, make decisions regarding commitment of funds and commitment of facilities, and provide oversight of the contractor's performance. A major challenge would be the transition of knowledge of facility operations and maintenance from the incumbent civil servant workforce to the contractor workforce. While the contract has since been modified multiple times, resulting in a blended NASA/ROME workforce across the facilities, the processes developed and implemented to capture and document facility knowledge from the incumbent subject matter experts, build training and certification programs, and grow individual skills across subject areas and across facilities, are worthy of documentation. This is the purpose of this paper.

Dunn, Steven C.↗
NASA NTRS2009

COTSAT Small Spacecraft Cost Optimization for Government and Commercial Use

Cost Optimized Test of Spacecraft Avionics and Technologies (COTSAT-1) is an ongoing spacecraft research and development project at NASA Ames Research Center (ARC). The prototype spacecraft, also known as CheapSat, is the first of what could potentially be a series of rapidly produced low-cost spacecraft. The COTSAT-1 team is committed to realizing the challenging goal of building a fully functional spacecraft for $500K parts and $2.0M labor. The project's efforts have resulted in significant accomplishments within the scope of a limited budget and schedule. Completion and delivery of the flight hardware to the Engineering Directorate at NASA Ames occurred in February 2009 and a cost effective qualification program is currently under study. The COTSAT-1 spacecraft is now located at NASA Ames Research Center and is awaiting a cost effective launch opportunity. This paper highlights the advancements of the COTSAT-1 spacecraft cost reduction techniques.

Swank, Aaron J.↗
NASA NTRS2010

Human Systems Integration in the Federal Government

Human Systems Integration principles and methods can be used to help integrate people, technology, and organizations in an effective and efficient manner. Over the past decade, a wide range of tools, techniques, and technologies have been developed by federal agencies to achieve significant cost and performance benefits. In this discussion, we will explore trends in military human systems integration and learn about the critical role being played by human performance and effectiveness research. We will also examine case studies on the planning and design of future human space flight vehicles, the national air space system and the first nuclear reactors to be built in the United States in over 30 years. And with an eye toward sustaining the discipline s principles and methods, we ll take a look at educating and training the next generation of human systems integration practitioners.

Jones, Patricia M.↗
NASA NTRS2010

Development of U.S. Government General Technical Requirements for UAS Flight Safety Systems Utilizing the Iridium Satellite Constellation

This slide presentation reviews the development of technical requirements for Unmanned Aircraft Systems (UAS) utilization of the Iridium Satellite Constellation to provide flight safety. The Federal Aviation Authority (FAA) required an over-the-horizon communication standard to guarantee flight safety before permitting widespread UAS flights in the National Air Space (NAS). This is important to ensure reliable control of UASs during loss-link and over-the-horizon scenarios. The core requirement was to utilize a satellite system to send GPS tracking data and other telemetry from a flight vehicle down to the ground. Iridium was chosen as the system because it is one of the only true satellite systems that has world wide coverage, and the service has a highly reliable link margin. The Iridium system, the flight modems, and the test flight are described.

Murray, Jennifer↗
NASA NTRS2010

Atmospheric CO2: Principal Control Knob Governing Earth's Temperature

Ample physical evidence shows that carbon dioxide (CO2) is the single most important climate-relevant greenhouse gas in Earth s atmosphere. This is because CO2, like ozone, N2O, CH4, and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can and does. Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO2 and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state.

Lacis, Andrew A.↗
NASA NTRS2012

Cryogenic Propellant Storage and Transfer Technology Demonstration: Prephase A Government Point-of-Departure Concept Study

The primary purpose of this study was to define a point-of-departure prephase A mission concept for the cryogenic propellant storage and transfer technology demonstration mission to be conducted by the NASA Office of the Chief Technologist (OCT). The mission concept includes identification of the cryogenic propellant management technologies to be demonstrated, definition of a representative mission timeline, and definition of a viable flight system design concept. The resulting mission concept will serve as a point of departure for evaluating alternative mission concepts and synthesizing the results of industry- defined mission concepts developed under the OCT contracted studies

Mulqueen, J. A.↗
NASA NTRS2014

Prognostics Uncertainty Management with Application to Government and Industry

Predictions about the future are contingent on future usage, but also on the quality of the models employed and the assessment of the current health state. These factors, amongst others, need to be considered to arrive at a prediction that is conducted through a rigorous method but where the confidence bounds are not prohibitively large.

Prognostics↗