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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

GOAL-to-HAL translation study

This report deals with the feasibility, problems, solutions, and mapping of a GOAL language to HAL language translator. Ground Operations Aerospace Language, or GOAL, is a test-oriented higher order language developed by the John F. Kennedy Space Center to be used in checkout and launch of the space shuttle. HAL is a structured higher order language developed by the Johnson Space Center to be used in writing the flight software for the onboard shuttle computers. Since the onboard computers will extensively support ground checkout of the space shuttle, and since these computers and the software development facilities on the ground use the HAL language as baseline, the translation of GOAL to HAL becomes significant. The issue of feasibility was examined and it was found that a GOAL to HAL translator is feasible. Special problems are identified and solutions proposed. Finally, examples of translation are provided for each category of complete GOAL statement.

Flanders, J. H.↗
NASA NTRS1986

The international aerospace industry - New challenges and opportunities for translation suppliers

Attention is given to the recent trend toward internationalization in the aerospace industry and its effects on commercial and governmental translation programs. The aerospace industry, once dominated by organizations from a small number of countries, is now widely international in scope. In effect, there has been in increase in the demand for translations from German, Japanese, Chinese, French and Spanish source material while that for translation from Russian source material has remained constant. The impact of the Challenger disaster on aerospace translation programs is discussed as well as the impact of international participation in Space Station research.

Rowe, T.↗
NASA NTRS1992

JTEC panel report on machine translation in Japan

The goal of this report is to provide an overview of the state of the art of machine translation (MT) in Japan and to provide a comparison between Japanese and Western technology in this area. The term 'machine translation' as used here, includes both the science and technology required for automating the translation of text from one human language to another. Machine translation is viewed in Japan as an important strategic technology that is expected to play a key role in Japan's increasing participation in the world economy. MT is seen in Japan as important both for assimilating information into Japanese as well as for disseminating Japanese information throughout the world. Most of the MT systems now available in Japan are transfer-based systems. The majority of them exploit a case-frame representation of the source text as the basis of the transfer process. There is a gradual movement toward the use of deeper semantic representations, and some groups are beginning to look at interlingua-based systems.

Carbonell, Jaime↗
NASA NTRS2004

A Low Mass Translation Mechanism for Planetary FTIR Spectrometry using an Ultrasonic Piezo Linear Motor

One of the key components of a Fourier Transform Infrared Spectrometer (FTIR) is the linear translation stage used to vary the optical path length between the two arms of the interferometer. This translation mechanism must produce extremely constant velocity motion across its entire range of travel to allow the instrument to attain high signal-to-noise ratio and spectral resolving power. A new spectrometer is being developed at the Jet Propulsion Laboratory under NASA s Planetary Instrument Definition and Development Program (PIDDP). The goal of this project is to build upon existing spaceborne FTIR spectrometer technology to produce a new instrument prototype that has drastically superior spectral resolution and substantially lower mass, making it feasible for planetary exploration. In order to achieve these goals, Alliance Spacesystems, Inc. (ASI) has developed a linear translation mechanism using a novel ultrasonic piezo linear motor in conjunction with a fully kinematic, fault tolerant linear rail system. The piezo motor provides extremely smooth motion, is inherently redundant, and is capable of producing unlimited travel. The kinematic rail uses spherical Vespel(R). rollers and bushings, which eliminates the need for wet lubrication, while providing a fault tolerant platform for smooth linear motion that will not bind under misalignment or structural deformation. This system can produce velocities from 10 - 100 mm/s with less than 1% velocity error over the entire 100-mm length of travel for a total mechanism mass of less than 850 grams. This system has performed over half a million strokes under vacuum without excessive wear or degradation in performance. This paper covers the design, development, and testing of this linear translation mechanism as part of the Planetary Atmosphere Occultation Spectrometer (PAOS) instrument prototype development program.

Heverly, Matthew↗
NASA NTRS2003

Rapid motor learning in the translational vestibulo-ocular reflex

Motor learning was induced in the translational vestibulo-ocular reflex (TVOR) when monkeys were repeatedly subjected to a brief (0.5 sec) head translation while they tried to maintain binocular fixation on a visual target for juice rewards. If the target was world-fixed, the initial eye speed of the TVOR gradually increased; if the target was head-fixed, the initial eye speed of the TVOR gradually decreased. The rate of learning acquisition was very rapid, with a time constant of approximately 100 trials, which was equivalent to <1 min of accumulated stimulation. These learned changes were consolidated over >or=1 d without any reinforcement, indicating induction of long-term synaptic plasticity. Although the learning generalized to targets with different viewing distances and to head translations with different accelerations, it was highly specific for the particular combination of head motion and evoked eye movement associated with the training. For example, it was specific to the modality of the stimulus (translation vs rotation) and the direction of the evoked eye movement in the training. Furthermore, when one eye was aligned with the heading direction so that it remained motionless during training, learning was not expressed in this eye, but only in the other nonaligned eye. These specificities show that the learning sites are neither in the sensory nor the motor limb of the reflex but in the sensory-motor transformation stage of the reflex. The dependence of the learning on both head motion and evoked eye movement suggests that Hebbian learning may be one of the underlying cellular mechanisms.

Non-NASA Center↗
NASA NTRS2007

MEMS Micro-Translation Device with Improved Linear Travel Capability

A microscopic translation device for a microelectromechanical system includes a pair of linear stator assemblies disposed in spaced relation to define an elongate channel. Each assembly is formed by a plurality of stators arranged in a row along the channel. A shuttle member is disposed between the stator assemblies for translating movement along the channel. The shuttle member includes a plurality of rotors extending outwardly from opposite sides. The shuttle is grounded through the stator assemblies and includes a mounting area for an object to be translated. Electrical lines are individually connected to alternate stators of a plurality of groups of the stators. A current supply sequentially supplies current through the electrical lines to the alternate stators so as to effect charging of the stators in a predetermined sequence. This produces a tangential capacitive force that causes translation of the shuttle.

Abushagur, Mustafa A. G.↗
NASA NTRS2009

Spatial Cognitive Performance During Adaptation to Conflicting Tilt-Translation Stimuli as a Sensorimotor Spaceflight Analog

The need to resolve new patterns of sensory feedback in altered gravitoinertial environments requires cognitive processes to develop appropriate reference frames for spatial orientation awareness. The purpose of this study was to examine deficits in spatial cognitive performance during adaptation to conflicting tilt-translation stimuli. Fourteen subjects were tilted within a lighted enclosure that simultaneously translated at one of 3 frequencies. Tilt and translation motion was synchronized to maintain the resultant gravitoinertial force aligned with the longitudinal body axis, resulting in a mismatch analogous to spaceflight in which the canals and vision signal tilt while the otoliths do not. Changes in performance on different spatial cognitive tasks were compared 1) without motion, 2) with tilt motion alone (pitch at 0.15, 0.3 and 0.6 Hz or roll at 0.3 Hz), and 3) with conflicting tilt-translation motion. The adaptation paradigm was continued for up to 30 min or until the onset of nausea. The order of the adaptation conditions were counter-balanced across 4 different test sessions. There was a significant effect of stimulus frequency on both motion sickness and spatial cognitive performance. Only 3 of 14 were able to complete the full 30 min protocol at 0.15 Hz, while 7 of 14 completed 0.3 Hz and 13 of 14 completed 0.6 Hz. There were no changes in simple visual-spatial cognitive tests, e.g., mental rotation or match-to-sample. There were significant deficits during 0.15 Hz adaptation in both accuracy and reaction time during a spatial reference task in which subjects are asked to identify a match of a 3D reoriented cube assemblage. Our results are consistent with antidotal reports of cognitive impairment that are common during sensorimotor adaptation with G-transitions. We conclude that these cognitive deficits stem from the ambiguity of spatial reference frames for central processing of inertial motion cues.

Kayanickupuram, A. J.↗
NASA NTRS2010

Motion Perception and Manual Control Performance During Passive Tilt and Translation Following Space Flight

This joint ESA-NASA study is examining changes in motion perception following Space Shuttle flights and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data has been collected on 5 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s) combined with body translation (12-22 cm, peak-to-peak) is utilized to elicit roll-tilt perception (equivalent to 20 deg, peak-to-peak). A forward-backward moving sled (24-390 cm, peak-to-peak) with or without chair tilting in pitch is utilized to elicit pitch tilt perception (equivalent to 20 deg, peak-to-peak). These combinations are elicited at 0.15, 0.3, and 0.6 Hz for evaluating the effect of motion frequency on tilt-translation ambiguity. In both devices, a closed-loop nulling task is also performed during pseudorandom motion with and without vibrotactile feedback of tilt. All tests are performed in complete darkness. PRELIMINARY RESULTS. Data collection is currently ongoing. Results to date suggest there is a trend for translation motion perception to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. DISCUSSION. The results of this study indicate that post-flight recovery of motion perception and manual control performance is complete within 8 days following short-duration space missions. Vibrotactile feedback of tilt improves manual control performance both before and after flight.

Clement, Gilles↗
NASA NTRS2014

Translational Research and Medicine at NASA: From Earth to Space and Back Again

The Space Environment provides many challenges to the human physiology and therefore to extended habitation and exploration. Translational research and medical strategies are meeting these challenges by combining Earth based medical solutions with innovative and developmental engineering approaches. Translational methodologies are current applied to spaceflight related dysregulations in the areas of: (1) cardiovascular fluid shifts, intracranial hypertension and neuro-ocular impairment 2) immune insufficiency and suppression/viral re-expression, 3) bone loss and fragility (osteopenia/osteoporosis) and muscle wasting, and finally 4) radiation sensitivity and advanced ageing. Over 40 years of research into these areas have met with limited success due to lack of tools and basic understanding of central issues that cause physiologic maladaptaion and distrupt homeostatis. I will discuss the effects of living in space (reduced gravity, increased radiation and varying atmospheric conditions [EVA]) during long-duration, exploration-class missions and how translational research has benefited not only space exploration but also Earth based medicine. Modern tools such as telemedicine advances in genomics, proteomics, and metabolomics (Omicssciences) has helped address syndromes, at the systemic level by enlisting a global approach to assessing spaceflight physiology and to develop countermeasures thereby permitting our experience in space to be translated to the Earth's medical community.

Goodwin, Thomas J.↗
NASA NTRS2018

Testing and Maturing a Mass Translating Mechanism for a Deep Space CubeSat

Near Earth Asteroid (NEA) Scout is a deep space satellite set to launch aboard NASA's Exploration Mission 1. The spacecraft fits within a CubeSat standard 6U (about 300 x 200 x 100 mm) and is designed to travel 1 AU over a 2.5 year mission to observe NEA VG 1991. The spacecraft will use an 86 sq.m solar sail to maneuver from lunar orbit to the NEA. One of the critical mechanisms aboard NEA Scout, the Active Mass Translator (AMT), has gone through rigorous design and test cycles since its conception in July of 2015. The AMT is a two-axis translation table required to balance the spacecraft's center of mass (CM) and solar sail center of pressure (CP) while also trimming disturbance torque created by off-nominal sail conditions. The AMT has very limited mass and volume requirements, but is still required to deliver a large translation range-about 160 x 68 mm-at sub mm accuracy and precision. The system is constrained to operate in complete exposure to space with limited power and data budgets for mechanical and thermal needs. The NEA Scout team developed and carried out a rigorous test suite for the prototype and engineering development unit (EDU). These tests uncovered numerous design failures and led to many failure investigations and iteration cycles. A paper was previously presented at the 43rd Aerospace Mechanisms Symposia entitled, "Development of a High Performance, Low Profile Translation Table with Wire Feedthrough for a Deep Space CubeSat". This paper will make note of specific lessons learned: manufacturing philosophy, testing ideologies for high-risk missions, thermal mitigation design for small, motor-driven mechanisms.

Few, Alex↗
NASA NTRS2019

Translating Phased Array Measurements of a Low-Noise Top-Mounted Propulsion Installation for a Supersonic Airliner

A novel translating-phased-array technique was applied during a model-scale validation test of low-noise propulsion concepts for supersonic transport aircraft. The test involved particle image velocimetry, far field and translating phased array acoustic measurements. This paper covers the translating phased array portion. Data were acquired for a series of nozzles with different chevron designs, both uninstalled and installed on a representative aircraft planform. The far field data confirmed the noise reduction potential of top-mounted installation, while the phased array results gave insights into how the reduction occurred and highlighted areas for improvement. This was the inaugural test for the new translating phased array, which measures source maps as seen by observers at different polar angles. Propagation effects through the free jet were documented for the different viewing angles. The source maps obtained were used to understand important aspects of the far field noise measurements.

Beamforming↗
NASA NTRS2020

Rotational and Translational Velocity and Acceleration Thresholds for the Onset of Cybersickness in Virtual Reality

This paper determined rotational and translational velocity and acceleration thresholds for the onset of cybersickness. Cybersickness causes discomfort and discourages the widespread use of virtual reality systems for both recreational and professional use. Visual motion or optic flow is known to be one of the main causes of cybersickness due to the sensory conflict it creates with the vestibular system. The aim of this experiment is to detect rotational and translational velocity and acceleration thresholds that cause the onset of cybersickness. Participants were exposed to a moving particle field in virtual reality for a few seconds per run. The field moved in different directions (longitudinal, lateral, roll, and yaw), with different velocity profiles (steady and accelerating), and different densities. Using a staircase procedure, that controlled the speed or acceleration of the field, we detected the threshold at which participant started to feel temporary symptoms of cybersickness. The optic flow was quantified for each motion type and by modifying the number of features, the same amount of optic flow was present in each scene. Having the same optic flow in each scene allows a direct comparison of the thresholds. The results show that the velocity and acceleration thresholds for rotational optic flow were significantly lower than for translational optic flow. The thresholds suggestively decreased with the decreasing particle density of the scene. Finally, it was found that all the rotational and translational thresholds strongly correlate with each other. While the mean values of the thresholds could be used as guidelines to develop virtual reality applications, the high variability between individuals implies that the individual tuning of motion controls would be more effective to reduce cybersickness while minimizing the impact on the experience of immersion.

Terenzi, Lorenzo↗
NASA NTRS1978

Interpolation and extrapolation of creep rupture data by the minimum commitment method. II - Oblique translation

An outline is presented of a new procedure, termed the oblique translation method, which emerged in the development of the focal point convergence method. Approaches for implementing the oblique translation method are discussed. It is shown that the new method is essentially a minimum commitment method when manually-graphically implemented, in the sense that the form of the functions involved are not forced into particular analytical forms. The individual constants and functions are independently determined. The minimum commitment concept is extended to the analysis of creep rupture data wherein each isothermal is to be generated by an oblique translation of the 'master curve' when plotted. Attention is given to a manual-graphical analysis, the preassessment of data, and an analysis by computer code.

Manson, S. S.↗
NASA NTRS1978

Monte Carlo solution of Boltzmann equation for a simple model of highly nonequilibrium diatomic gases - Translational rotational energy relaxation

Theoretical results pertaining to internally excited translational-rotational energy relaxation in a spatially uniform diatomic gas far removed from solid boundaries are obtained by solving the Boltzmann equation by means of the Monte Carlo direct simulation method. The analysis is based on calculations involving three different types of initial conditions: equilibrium, nonequilibrium-equipartition (i.e., equipartition is satisfied, but the distributions are perturbed), and nonequilibrium-nonequipartition (i.e., both equipartition and the distributions are perturbed). Results of monatomic-gas simulations are also included to facilitate comparisons with the coupled translational-rotational relaxation simulations, and some simulations for a normal shock-wave structure are briefly examined. The results show that: (1) single-step transitions are the significant mechanisms of intermodal energy transfer; (2) translational-rotational transitions are coupled most efficiently for low-lying states of rotationally excited molecules and least efficiently for highly rotationally excited molecules; and (3) relaxation occurs via a successive set of distributions that are not Maxwell-Boltzmann (nonlocal Maxwellian).

Yoshikawa, K. K.↗
NASA NTRS1980

Wind tunnel apparatus for translational oscillation experiments

A full-model translational oscillation apparatus has been developed for the wind-tunnel determination, in a wide speed range, of all three moment derivatives due to translational acceleration. The apparatus can be employed, in principle, for both vertical and horizontal oscillation experiments and can be used, therefore, to obtain moment derivatives due to alpha or beta, respectively. This information can be obtained directly if the model can be oscillated in the translational mode only, or indirectly - by utilizing some complementary information from angular oscillation experiments - if the model is allowed to also perform a small angular oscillation. The apparatus employs modern, fully digital instrumentation and an extensive use of auto and cross correlation techniques is made in the data reduction procedure

Orlik-Ruckemann, K. J.↗
NASA NTRS1980

A translator writing system for microcomputer high-level languages and assemblers

In order to implement high level languages whenever possible, a translator writing system of advanced design was developed. It is intended for routine production use by many programmers working on different projects. As well as a fairly conventional parser generator, it includes a system for the rapid generation of table driven code generators. The parser generator was developed from a prototype version. The translator writing system includes various tools for the management of the source text of a compiler under construction. In addition, it supplies various default source code sections so that its output is always compilable and executable. The system thereby encourages iterative enhancement as a development methodology by ensuring an executable program from the earliest stages of a compiler development project. The translator writing system includes PASCAL/48 compiler, three assemblers, and two compilers for a subset of HAL/S.

Collins, W. R.↗
NASA NTRS1982

Effects of translational nonequilibrium on vacuum plume expansions

The plume flowfield of a helium vent nozzle exhausting into a vacuum is defined by two techniques: the method of characteristics and the direct-simulation Monte Carlo method. The method of characteristics is shown to severely underpredict gas static temperatures due to the assumption of translational equilibrium inherent in the continuum formulation. Mass flow per unit solid angle is shown to be accurately predicted for this flowfield by the method of characteristics until the flow angle approaches within 10 deg of the maximum Prandtl-Meyer expansion angle. Improved treatment of the noncontinuum flow within the nozzle (near the lip) is postulated to have minor effects on the accuracy of this continuum method in comparison with translational nonequilibrium in the external flowfield. Possible treatment of translational nonequilibrium by the method of characteristics is discussed.

Guernsey, C. S.↗
NASA NTRS1985

Coupled translations of the 64-meter antenna subreflector supports

The Tricone subreflector assembly of the 64-m diameter antenna is supported from the apex of the quadripod by six flexure rods. The subreflector can be translated in the three orthogonal axes by jackscrews at the ends of each rod. The arrangement of the six rods is described and analysis of the position errors introduced by coupled translation is presented. The results indicate that negligible RF gain losses caused by axis-coupled translations (less than 0.05 dB) are possible at X-band (8.45 GHz) operation.

Katow, M. S.↗