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May 23, 2011
05/11
by
Nowak, Michael A.; Wagoner, Robert V.; Begelman, Mitchell C.; Lehr, Dana E
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The Rossi X-Ray Timing Explorer has made feasible for the first time the search for high-frequency (greater than or equal to 100 Hz) periodic features in Black Hole Candidate (BHC) systems. Such a feature, with a 67 Hz frequency, recently has been discovered in the BHC GRS 1915105 (Morgan, Remillard, & Greiner). This feature is weak (rms variability approx. 0.3%-1.6%), stable in frequency (to within approx. 2 Hz) despite appreciable luminosity fluctuations, and narrow (quality factor Q...
Topics: DECODERS, COMPUTER PROGRAMS, CODERS, BINARY CODES, TRADEOFFS, CONSTRUCTION
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286
Jul 26, 2010
07/10
by
NON
texts
eye 286
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A pair of spaced collars are mounted at right angles on a clamp body by retaining rings which enable the collars to rotate with respect to the clamp body. Mounting posts extend through aligned holes in the collars and clamp body. Each collar can be clamped onto the inserted post while the clamp body remains free to rotate about the post and collar. The clamp body is selectively clamped onto each post.
Topics: ECONOMICS, LAUNCHING, MARS PROBES, PROBABILITY THEORY, COSTS, RELIABILITY, SENSITIVITY, TRADEOFFS
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204
Jun 13, 2011
06/11
by
Henderson, Brenda; Norum, Thomas; Bridges, Jame
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The effect of airfoil-shaped vanes placed in the fan stream of a BPR 8 coannular nozzle model system on the resulting jet noise was investigated. The experiments used a Modern Design of Experiments approach to investigate the impact of a range of vane parameters on the noise reduction achieved at representative takeoff conditions. The experimental results showed that the installation of the vanes decreased low frequency noise radiation in the downstream peak-noise direction and increased high...
Topics: MACHINE LEARNING, ROBUSTNESS (MATHEMATICS), GRADIENTS, TEMPORAL RESOLUTION, CONSTRAINTS, TRADEOFFS,...
432
432
Jun 13, 2011
06/11
by
Flaherty, Roger; Stocklin, Frank; Weinberg, Aaro
texts
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NASA's Tracking and Data Relay Satellite System (TDRSS) is now in its 23rd year of operations and its spacecraft fleet includes three second-generation spacecraft launched since the year 2000; a figure illustrates the first generation TDRSS spacecraft. During this time frame the TDRSS has provided communications relay support to a broad range of missions, with emphasis on low-earth-orbiting (LEO) spacecraft that include unmanned science spacecraft (e.g., Hubble Space Telescope), and human...
Topics: NONLINEARITY, ACOUSTIC FATIGUE, STATIC LOADS, FUSELAGES, DEGREES OF FREEDOM, TRADEOFFS
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246
May 31, 2011
05/11
by
Havelund, Klaus; Rosu, Grigor
texts
eye 246
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We present a rewriting-based algorithm for efficiently evaluating future time Linear Temporal Logic (LTL) formulae on finite execution traces online. While the standard models of LTL are infinite traces, finite traces appear naturally when testing and/or monitoring red applications that only run for limited time periods. The presented algorithm is implemented in the Maude executable specification language and essentially consists of a set of equations establishing an executable semantics of LTL...
Topics: VISCOSITY, AIRFOILS, GENETIC ALGORITHMS, TRADEOFFS, STEADY STATE, PARAMETERIZATION, NAVIER-STOKES...
In the current period of fiscal restraint, the acquisition of weapon systems has come under ever increasing scrutiny. Costs of these systems are influenced by performance characteristics of the system and schedule demands placed on the acquisition process. The objective of this thesis is to investigate previous research performed in the area of cost, schedule, and performance tradeoffs in the acquisition of major weapon systems. Results of the literature review indicate that several...
Topics: Tradeoffs, Weapon Systems, Cost Estimating Relationships, CERs, Cost Estimates, Performance,...
384
384
Jun 13, 2011
06/11
by
McGreevy, Michael W
texts
eye 384
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Perilog, a context intensive text mining system, is used as a discovery tool to explore topics and concerns in ''Decision Making at NASA,'' chapter 6 of the Columbia Accident Investigation Board (CAIB) Report, Volume I. Two examples illustrate how Perilog can be used to discover highly significant safety-related information in the text without prior knowledge of the contents of the document. A third example illustrates how ''if-then'' statements found by Perilog can be used in logical analysis...
Topics: SPACE EXPLORATION, NASA PROGRAMS, HUMAN PERFORMANCE, RISK, RELIABILITY, CHARACTERIZATION, SAFETY,...
197
197
Jul 26, 2010
07/10
by
Sohn, R. A.; Stroup, J. W
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eye 197
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The input for global atmospheric chemistry models was generated for baseline High Speed Civil Transport (HSCT) configurations at Mach 1.6, 2.2, and 3.2. The input is supplied in the form of number of molecules of specific exhaust constituents injected into the atmosphere per year by latitude and by altitude (for 2-D codes). Seven exhaust constituents are currently supplied: NO, NO2, CO, CO2, H2O, SO2, and THC (Trace Hydrocarbons). An eighth input is also supplied, NO(x), the sum of NO and NO2....
Topics: ALGORITHMS, BANDWIDTH, CODING, DATA COMPRESSION, SIGNAL DISTORTION, CHANNEL CAPACITY, CODERS,...
352
352
May 28, 2011
05/11
by
Tiampo, Kristy F
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In this project, we attempted to model the deformation pattern due to the magmatic source at Long Valley caldera using a real-value coded genetic algorithm (GA) inversion similar to that found in Michalewicz, 1992. The project has been both successful and rewarding. The genetic algorithm, coded in the C programming language, performs stable inversions over repeated trials, with varying initial and boundary conditions. The original model used a GA in which the geophysical information was coded...
Topics: STRUCTURAL DESIGN, COMPUTER AIDED DESIGN, COMPUTER PROGRAMS, NASTRAN, PANELS, FAILURE, COSTS,...
Recent research has shed light on the various tradeoffs involved in carbon forestry, i.e. the pursuit of international forestry projects to help mitigate climate change. This article contributes to these debates by highlighting the importance of resource quality and degradation in evaluating project benefits and tradeoffs. Focusing on the case of an industrial tree plantation in Uganda, the Kachung Forest Project, we highlight how the livelihoods of communities surrounding the reserve have been...
Topics: Carbon forestry, Commodification of nature, Community benefits, Degradation, Resource quality,...
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343
Jun 26, 2010
06/10
by
NON
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Gamma ray absorption through interactions with galactic radiation, electrons, and pair producing matter
Topics: AUXILIARY PROPULSION, HYDROGEN OXYGEN ENGINES, PROPULSION SYSTEM CONFIGURATIONS, SPACE SHUTTLES,...
191
191
Jul 12, 2010
07/10
by
Wynn, S. C
texts
eye 191
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No Abstract Available
Topics: APOLLO 13 FLIGHT, EXTRAVEHICULAR ACTIVITY, MISSION PLANNING, LUNAR EXPLORATION, LUNAR GEOLOGY,...
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282
May 31, 2011
05/11
by
Duarte, Luis Albert
texts
eye 282
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The US civil aerospace program has been a great contributor to the creation and implementation of techniques and methods to identify, analyze, and confront risk. NASA has accomplished mission success in many instances, but also has had many failures. Anomalies have kept the Agency from achieving success on other occasions, as well. While NASA has mastered ways to prevent risks, and to quickly and effectively react and recover from anomalies or failures, it was not until few years ago that a...
Topics: DISPLAY DEVICES, SPATIAL RESOLUTION, TRADEOFFS, GRAY SCALE, SYSTEMS ENGINEERING, TECHNOLOGY...
There have been two scenarios in which the Payload Safety Review Panel (PSRP) has considered a Probabilistic Risk Assessment (PRA) a viable tool. For use in considering trade-offs during the initial design. When in a waiver condition to explain rationale for acceptance. The PSRP would consider the use of PRA in other applications where credible.
Topics: NASA Technical Reports Server (NTRS), PAYLOADS, SAFETY, RISK, TRADEOFFS, DESIGN OPTIMIZATION,...
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May 23, 2011
05/11
by
D'Antoni, Hector L.; Schaebitz, Fran
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Predictions of the future evolution of the earth's atmospheric chemistry and its impact on global circulation patterns are based on Global Climate Models (GCMs) that integrate the complex interactions of the biosphere, atmosphere and the oceans. Most of the available records of climate and environment are short-term records (from decades to a few hundred years) with convolved information of real trends and short-term fluctuations. GCMs must be tested beyond the short-term record of climate and...
Topics: MASSIVELY PARALLEL PROCESSORS, COMMUNICATION NETWORKS, SUPERCOMPUTERS, MEMORY (COMPUTERS),...
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184
Jul 6, 2010
07/10
by
KOBRYNSKI, M
texts
eye 184
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THE RELATION BETWEEN THE TOTAL SOUND-PRESSURE FIELD EMITTED BY A STATIONARY ROTATING JET AND THE SOUND FIELD FROM THAT SAME JET IN MOTION, OBSERVED AT A FIXED POINT ON THE GROUND, IS STUDIED BY INTRODUCING INTO THE GENERALIZED EQUATION FOR THE LOCAL OVER-ALL SOUND-PRESSURE LEVEL, WHOSE FORM IS RECALLED, A NEW CONVECTION INDEX DERIVED FROM THE RIBNER EXPRESSION. THE INFLUENCE OF THE FLIGHT SPEED ON THE SOUND EMISSION IS DEMONSTRATED OVER A BROAD RANGE OF ANGLES (FROM 20 TO 160 DEG WITH RESPECT...
Topics: INFORMATION SYSTEMS, LAW (JURISPRUDENCE), LIBRARIES, NASA PROGRAMS, INFORMATION RETRIEVAL, SPACE...
Mendeley Climate Change Library
47
47
Jul 5, 2019
07/19
by
Zhan Tian; Yilong Niu; Dongli Fan; Laixiang Sun; Honglin Zhong; Jia Deng; Francesco N. Tubiello
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China is the largest rice producing and consuming country in the world, accounting for more than 25% of global production and consumption. Rice cultivation is also one of the main sources of anthropogenic methane (CH4) and nitrous oxide (N2O) emissions. The challenge of maintaining food security while reducing greenhouse gas emissions is an important tradeoff issue for both scientists and policy makers. A systematical evaluation of tradeoffs requires attention across spatial scales and over...
Topics: Agricultural CH4 and N2O emissions, China, Climate change, Mitigation tradeoffs, Model coupling,...
From the bitsavers.org collection, a scanned-in computer-related document. dec :: tech reports :: WRL-89-9
Topics: cache, multititan, cpu, instruction, tradeoffs, data, pipestage, wrl, latency, tag, multititan cpu,...
292
292
Jun 13, 2011
06/11
by
Chew, Gilbert; Pelaccio, Dennis G.; Chiroux, Robert; Pervan, Sherry; Rauwolf, Gerald A.; White, Charle
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Science Applications International Corporation (SAIC), with support from NASA Marshall Space Flight Center, has conducted a preliminary study to compare options for augmenting the thrust of a conventional nuclear electric propulsion (NEP) system. These options include a novel nuclear propulsion system concept known as Hybrid Indirect Nuclear Propulsion (HINP) and conventional chemical propulsion. The utility and technical feasibility of the HINP concept are assessed, and features and potential...
Topics: DECISION MAKING, DESIGN ANALYSIS, SYSTEMS ENGINEERING, AEROSPACE SYSTEMS, AEROSPACE VEHICLES,...
Governments and privately-held utilities will have to drastically reduce their carbon emissions to mitigate climate change. Such reductions will require transitioning electrical infrastructure to rely on cleaner fuels and power-generation technologies. Despite the myriad factors influencing both the process and eventual outcome of these transitions, it is typically transitions’ cost and individuals’ willingness to pay (WTP) for them that dominate both strategic planning and political...
Topics: Energy portfolios, Multi-criteria decision analysis, Social and environmental attributes,...
The feasibility of a scientific instrument package (SIP) that will satisfy the requirements of the large space telescope was established. A reference configuration serving as a study model and data which will aid in the trade-off studies leading to the final design configuration are reported.
Topics: NASA Technical Reports Server (NTRS), HUBBLE SPACE TELESCOPE, SPACECRAFT INSTRUMENTS, MODELS,...
286
286
Jul 11, 2010
07/10
by
LEBLANC, G
texts
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DISTANCE PREDICTING METHODS FOR AIRCRAFT BRAKING PERFORMANCE IS DISCUSSED FOR THE CASE WHEN BRAKING IS NOT LIMITED BY THE BRAKES, BUT BY THE CHARACTERISTICS OF TIRE-RUNWAY CONTACT. RECENTLY DEVELOPED FIGHTER AND LARGE CAPACITY TRANSPORT AIRCRAFT REQUIRE THAT STOPPING DISTANCES AND RUNWAY LENGTHS BE ACCURATELY CORRELATED FOR DIFFERENT TOUCHDOWN VELOCITIES, WIND, AND RUNWAY CONDITIONS.
Topics: NUCLEAR ELECTRIC PROPULSION, SPACECRAFT CONFIGURATIONS, PAYLOADS, SPACECRAFT DESIGN, TEMPERATURE...
Conclusions: a) Proper software abstractions should enable rapid-exploration of platform-specific optimizations/ tradeoffs. b) Pseudo-spectra! methods are marginally viable for at least some classes of petascaie problems. i.e., GPU based machine with good bisection would be best. c) Scalability at exascale is possible, but the necessary resolution will make algorithm prohibitively expensive. Efficient implementations of realistic global transposes are mtricate and tedious in MPI. PS at...
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, OPTIMIZATION, SPECTRAL METHODS, SPHERES,...
The IVHM Project in the Aviation Safety Program has funded research in electrical power system (EPS) health management. This problem domain contains both discrete and continuous behavior, and thus is directly relevant for the hybrid diagnostic tool HyDE. In FY2007 work was performed to expand the HyDE diagnosis model of the ADAPT system. The work completed resulted in a HyDE model with the capability to diagnose five times the number of ADAPT components previously tested. The expanded diagnosis...
Topics: NASA Technical Reports Server (NTRS), DIAGNOSIS, FLIGHT SAFETY, AIRCRAFT SAFETY, TRADEOFFS, TUNING,...
276
276
Sep 20, 2010
09/10
by
Rombach, H. Dieter; Ulery, Bradford T.; Valett, Jon D
texts
eye 276
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Organization-wide measurement of software products and processes is needed to establish full life cycle control over software products. The Software Engineering Laboratory (SEL)--a joint venture between NASA GSFC, the University of Maryland, and Computer Sciences Corporation--started measurement of software development more than 15 years ago. Recently, the measurement of maintenance was added to the scope of the SEL. In this article, the maintenance measurement program is presented as an...
Topics: LAUNCH VEHICLES, REENTRY VEHICLES, REUSABLE SPACECRAFT, SPACECRAFT DESIGN, SPACECRAFT LAUNCHING,...
Significant improvements have been made to the ACM model of the CDS, enabling accurate predictions of dynamic operations with fewer assumptions. The model has been utilized to predict how CDS performance would be impacted by changing operating parameters, revealing performance trade-offs and possibilities for improvement. CDS efficiency is driven by the THP coefficient of performance, which in turn is dependent on heat transfer within the system. Based on the remaining limitations of the...
Topics: NASA Technical Reports Server (NTRS), HEAT TRANSFER, DISTILLATION, SIMULATION, TRADEOFFS,...
412
412
Jul 12, 2010
07/10
by
Elam, W. W.; Orrok, G. T
texts
eye 412
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No Abstract Available
Topics: COST ANALYSIS, PROJECT PLANNING, SPACE TUGS, SPACECRAFT DESIGN, SPACE SHUTTLES, SPACE...
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864
Sep 20, 2010
09/10
by
NON
texts
eye 864
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The Earth Observing System Data and Information System (EOSDIS) is described in terms of its data volume, data rate, and data distribution requirements. Opportunities for data compression in EOSDIS are discussed.
Topics: COST ANALYSIS, EXOBIOLOGY, FUNCTIONAL DESIGN SPECIFICATIONS, HANDBOOKS, TRADEOFFS, COST...
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205
Sep 20, 2010
09/10
by
Anderson, J. R
texts
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The performance of a broad-beam, three-grid, ion extraction system incorporating radio frequency (RF) mass discrimination was investigated experimentally. This testing demonstrated that the system, based on a modified single-stage Bennett mass spectrometer, can discriminate between ionic species having about a 2-to-1 mass ratio while producing a broad-beam of ions with low kinetic energy (less than 15 eV). Testing was conducted using either argon and krypton ions or atomic and diatomic oxygen...
Topics: EXTRATERRESTRIAL RESOURCES, FABRICATION, MANUFACTURING, MOON, TRADEOFFS, MATERIALS, MINERALS,...
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224
Jul 12, 2010
07/10
by
Troester, R
texts
eye 224
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comment 0
No Abstract Available
Topics: AERONAUTICAL ENGINEERING, RESEARCH AND DEVELOPMENT, COMPUTER PROGRAMS, COUNTDOWN, SPACECRAFT...
397
397
Jun 12, 2011
06/11
by
Clancey, William J.; Semple, Abigail, et al; Sierhaus, Maarten; Alena, Richard L.; Berrios, Daniel; Dowding, John; Graham, Jeffrey S.; Tyree, Kim S.; Hirsh, Robert L.; Garry, W. Brent
texts
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We have developed and tested an advanced EVA communications and computing system to increase astronaut self-reliance and safety, reducing dependence on continuous monitoring and advising from mission control on Earth. This system, called Mobile Agents (MA), is voice controlled and provides information verbally to the astronauts through programs called personal agents. The system partly automates the role of CapCom in Apollo-including monitoring and managing EVA navigation, scheduling, equipment...
Topics: COMMERCIAL AIRCRAFT, TAIWAN, SELECTION, SEATS, PASSENGERS, EXPANSION, CIVIL AVIATION, AIRLINE...
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332
Sep 20, 2010
09/10
by
Hoad, Danny R.; Althoff, Susan L.; Elliott, Joe W.; Sailey, Richard H
texts
eye 332
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An experimental investigation was conducted in the 14- by 22-Foot Subsonic Tunnel at the NASA Langley Research Center to measure the inflow into a scale model helicopter rotor in forward flight (mu = 0.35). The measurements were made with a two-component Laser Velocimeter (LV) one chord above the plane formed by the path of the rotor tips (tip-path-plane). A conditional sampling technique was used to determine the position of the rotor at the time that each velocity measurement was made so that...
Topics: COST ANALYSIS, EXOBIOLOGY, FUNCTIONAL DESIGN SPECIFICATIONS, HANDBOOKS, TRADEOFFS, COST...
This memorandum explores a host of considerations meriting attention from those who are concerned with designing organizational structures for development and control of a large scale educational telecommunications system using satellites. Part of a broader investigation at Washington University into the potential uses of fixed/broadcast satellites in U.S. education, this study lays ground work for a later effort to spell out a small number of hypothetical organizational blueprints for such a...
Topics: NASA Technical Reports Server (NTRS), COMMUNICATION SATELLITES, EDUCATION, TELECOMMUNICATION,...
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244
May 23, 2011
05/11
by
Shen, Y.; Shen, Z. J.; Shen, G. T.; Yang, B. C
texts
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By the measurement theory of quantum mechanics and the method of Fourier transform,we proved that the wave function psi(x,y,z,t)= (8/((2(pi)(2L(exp (1/2)))(exp 3))(Phi(L,t,x)Phi(L,t,y)Phi(L,t,z)). According to the theory that the velocity of any particle can not be larger than the velocity of light and the Born interpretation, when absolute value of delta greater than (ct L),Phi(L,t,delta) = 0. But according to the calculation, we proved that for some delta, even if absolute value of delta is...
Topics: TRADEOFFS, DISCRIMINATION, DISPLAY DEVICES, GRAY SCALE, PERFORMANCE PREDICTION, SPATIAL RESOLUTION,...
408
408
Jun 26, 2011
06/11
by
deGroh, Henry C., III; Daniels, C.; Dunlap, P.; Steinetz, B
texts
eye 408
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The elastomer seal needed to seal in cabin air when NASA s Crew Exploration Vehicle is docked is exposed to space prior to docking. While open to space, the seal might be hit by orbital debris or meteoroids. The likelihood of damage of this type depends on the size of the particle. Our campaign is designed to find the smallest particle that will cause seal failure resulting in loss of mission. We will then be able to estimate environmental risks to the seal. Preliminary tests indicate seals can...
Topics: MARS MISSIONS, INFLATABLE STRUCTURES, DESCENT, LANDING SITES, DEPLOYMENT, MARS SURFACE, FLIGHT...
The MODIS aerosol cloud mask is based on a spatial variability test, using the assumption that aerosols are more homogeneous than clouds. On top of this first line of defense are a series of additional tests based on threshold values and ratios of various MODIS channels. The goal is to eliminate clouds and keep the aerosol. How well have we succeeded? There have been several studies showing cloud contamination in the MODIS aerosol product and several alternative cloud masks proposed. There are...
Topics: NASA Technical Reports Server (NTRS), IMAGING SPECTROMETERS, MODIS (RADIOMETRY), AEROSOLS,...
A mathematical analysis of the tradeoffs and requirements was performed to develop an improved array design which will give stronger returns at lower elevation angles and reduce pulse spread in the return. It was determined that a zenith angle of 75deg can be obtained with an array with an area of 0.28 sq m, if the array is shaped on the surface of a 45 deg cone whose axis is coincident to the satellite axis. The total weight of the truncated pyramid array with 270 cube corners is calculated to...
Topics: NASA Technical Reports Server (NTRS), GEOS 3 SATELLITE, LASERS, REFLECTORS, MATHEMATICAL MODELS,...
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717
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Composition and effects of radioprotectors on acceleration tolerance, hypoxia toxicity, radiation protection, and dynamic space flight stress in animals
Topics: COSTS, EARTH ORBITS, SPACE SHUTTLES, COST ANALYSIS, COST ESTIMATES, PROJECT MANAGEMENT, SPACE...
The design considerations of bearing selection, bearing fits, bearing installation, and thermal control are discussed for a gimbal with a high stiffness, low friction torque requirement. Tradeoffs between a quad set of small diameter spread apart or a large diameter bearing pair resulted in a cleaner, lighter, stiffer unit with the latter selection. Bearing fits were designed to eliminate clearances with tolerances of .00127 mm 00005 in) on the bearing shafts and housings. The problems in...
Topics: NASA Technical Reports Server (NTRS), BEARINGS, FRICTION, GIMBALS, EQUIPMENT SPECIFICATIONS,...
The Intensity Dependent Spread (IDS) procedure is an image-processing technique based on a model of the processing which occurs in the human visual system. IDS processing is relevant to many aspects of machine vision and image processing. For quantum limited images, it produces an ideal trade-off between spatial resolution and noise averaging, performs edge enhancement thus requiring only mean-crossing detection for the subsequent extraction of scene edges, and yields edge responses whose...
Topics: NASA Technical Reports Server (NTRS), COMPUTER VISION, EDGE DETECTION, IMAGE PROCESSING, BANDWIDTH,...
902
902
May 28, 2011
05/11
by
Litvin, F. L.; Egelja, A.; Tan, J.; Chen, D. Y.-D.; Heath, G
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The use of face gears in power transmission and drive systems has a significant number of benefits. Face gears allow a variety of new transmission arrangements as well as high reduction ratio capability. This leads to drive system weight reduction and improvements in performance. In this work, basic information about the design and analysis of face gear drives is presented. The work considers face gears in mesh with spur involute pinions for both intersecting axes and offset drives. Tooth...
Topics: DESIGN ANALYSIS, OPTICAL EQUIPMENT, OPTICAL RADAR, SYSTEMS ANALYSIS, TRADEOFFS, FRESNEL LENSES,...
Work in two somewhat distinct areas is presented. First, the optimal system design problem for a Mars-roving vehicle is attacked by creating static system models and a system evaluation function and optimizing via nonlinear programming techniques. The second area concerns the problem of perturbed-optimal solutions. Given an initial perturbation in an element of the solution to a nonlinear programming problem, a linear method is determined to approximate the optimal readjustments of the other...
Topics: NASA Technical Reports Server (NTRS), MARS SURFACE, NONLINEAR PROGRAMMING, ROVING VEHICLES,...
This slide presentation reviews the trade studies that were done for the Hyperspectral Environmental Suite (HES). The goal of the trade studies was to minimize instrument cost and risk while producing scientifically useful products. Three vendors were selected to perform the trade study, and were to conduct 11 studies, with the first study a complete wish list of things that scientists would like from GEO orbit to the 11th study which was for a Reduced Accommodation Sounder (RAS) which would...
Topics: NASA Technical Reports Server (NTRS), COSTS, SOUNDING, INSTRUMENT PACKAGES, SATELLITE-BORNE...
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311
Jul 11, 2010
07/10
by
Conner, D. W.; Thompson, G. O
texts
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Active controls technology offers great promise for significantly smoothing the ride, and thus improving public and air carrier acceptance, of certain types of transport aircraft. Recent findings which support this promise are presented in the following three pertinent areas: (1) Ride quality versus degree of traveler satisfaction; (2) significant findings from a feasibility study of a ride smoothing system; and (3) potential ride problems identified for several advanced transport concepts.
Topics: AIR TRANSPORTATION, TURBOPROP AIRCRAFT, AIRLINE OPERATIONS, COMMERCIAL AIRCRAFT, COST ANALYSIS,...
No abstract available
Topics: NASA Technical Reports Server (NTRS), HUMAN PERFORMANCE, PERFORMANCE PREDICTION, SYSTEMS...
The need to store and retrieve large quantities of data at modest cost has generated the need for an economical, compact, archival mass storage system. Very significant improvements in the state-of-the-art of mass storage systems have been accomplished through the development of a number of magnetic, electro-optical, and other related devices. This study was conducted in order to do a trade-off between these data storage devices and the related technologies in order to determine an optimum...
Topics: NASA Technical Reports Server (NTRS), DATA STORAGE, TECHNOLOGY ASSESSMENT, TRADEOFFS, COMPARISON,...
The balance between receiver complexity and the required satellite equivalent isotropically radiated power (EIRP) for Direct Broadcast Satellite-Radio (DBS-R) service is addressed. In general the required receiver complexity and cost can be reduced at the expense of higher space-segment cost by allowing a higher satellite EIRP. The tradeoff outcome is sensitive to the total number of anticipated receivers in a given service area, the number of audio programs, and the required audio quality. An...
Topics: NASA Technical Reports Server (NTRS), BROADCASTING, RADIO RECEIVERS, SATELLITE COMMUNICATION,...
Preliminary design studies were performed to define a turbotip lift/cruise fan propulsion system for a Navy multimission aircraft. The fan is driven by the exhausts of the YJ97-GE-100 turbojet or a 20 percent Growth J97 configuration as defined during the studies. The LCF459 fan configuration defined has a tip diameter of 1.50 meters (59.0 inches) and develops a design point thrust of 75,130 N (16,890 lbs) at a fan pressure ratio of 1.319. The fan has an estimated weight of 386 kg (850 lbs)....
Topics: NASA Technical Reports Server (NTRS), J-97 ENGINE, V/STOL AIRCRAFT, COST ANALYSIS, ENGINE DESIGN,...
304
304
Jul 6, 2010
07/10
by
BROCKKOETTER, G
texts
eye 304
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IN 11 UNTRAINED AND 11 HIGHLY TRAINED SUBJECTS, THE ALTERATIONS OF CELL ENZYMES, GLUCOSE, CHOLESTEROL AND 17-OH-CORTICOSTEROIDS WERE STUDIED IN RESPONSE TO PHYSICAL EXERCISE AND AS A FUNCTION OF THE PHYSICAL STATUS. THE TRAINING STATUS WAS QUANTIFIED BY MEASURING THE MAXIMUM OXYGEN UPTAKE. THE TWO GROUPS OF SUBJECTS SHOWED DIFFERENCES IN THEIR RESPONSES TO PHYSICAL EXERCISE WITH RESPECT TO ALDOLASE, GLUCOSE AND 17-OH-CORTICOSTEROIDS. THERE WAS NO EVIDENCE FOR A CLOSE RELATIONSHIP BETWEEN THE...
Topics: SPACE SHUTTLES, WEIGHT ANALYSIS, SPACECRAFT DESIGN, SPACECRAFT STRUCTURES, STRUCTURAL WEIGHT,...
The computer program CASCOMP, which may be used in comparative design studies of lighter than air vehicles by rapidly providing airship size and mission performance data, was prepared and documented. The program can be used to define design requirements such as weight breakdown, required propulsive power, and physical dimensions of airships which are designed to meet specified mission requirements. The program is also useful in sensitivity studies involving both design trade-offs and...
Topics: NASA Technical Reports Server (NTRS), AIRSHIPS, COMPUTER PROGRAMS, PERFORMANCE, SIZING (SHAPING),...
