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  • General Chemistry  (11,249)
  • COMMUNICATIONS  (1,377)
  • BIOTECHNOLOGY  (1,374)
  • Cell & Developmental Biology
  • 1970-1974  (8,451)
  • 1925-1929  (4,838)
  • 1915-1919  (1,967)
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  • 1
    Publication Date: 2006-01-11
    Description: Communications between civilizations within our galaxy at the present level of radio engineering is possible, although civilizations must begin to search for each other to achieve this. If an extra-terrestrial civilization possessing a technology at our level wishes to make itself known and will transmit special radio signals to do this, then it can be picked up by us at a distance of several hundreds of light years using already existing radio telescopes and specially built radio receivers. If it wishes, this civilization can also send us information without awaiting our answer.
    Keywords: COMMUNICATIONS
    Type: Inhabited Space, Pt. 2 (NASA-TT-F-820); p 79-82
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  • 2
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    Publication Date: 2006-01-11
    Description: A human habitat on the lunar surface requires energy recycling metabolites based on the utilization of vegetative plants that are good photosynthesizers. Selection criteria involve reactions to fertilization by human excrements, suitability as food for man (with or without fractionation), physiological effects of prolonged ingestion of these plants, and technical methods for returning inedible portions back into the cycle.
    Keywords: BIOTECHNOLOGY
    Type: Inhabited Space, Pt. 2 (NASA-TT-F-820); p 53-61
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  • 3
    Publication Date: 2006-01-11
    Description: Acoustic passenger comfort in railroad cars is represented by the following values: Total noise level in db, octave sound spectrum in db, and indices of intelligibility. The noise level perceived inside the car results from two components: one due to the penetration of air noise, and another due to the transmission of vibrations through solids. Measurement results show the necessity of improving bogie and bogie-body connections, intensification of soundproofing of the floor, adaption of windows with double panes, etc.
    Keywords: BIOTECHNOLOGY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 218-223
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  • 4
    Publication Date: 2006-01-11
    Description: Streetcar noise was investigated on different lines and inside different types by sonometer measurements. The results showed variations of the total noise intensity between 88-97 db. In some squares with heavy traffic the total noise intensity reached 106 db. Noise intensity measurements inside different types of streetcars brought to light high values between 101-106 db, while in the case of the new silent type of streetcar the values were 86-87 db. The importance of the sound discomfort produced by streetcar traffic is emphasized, inasmuch as the noise intensity exceeds by far the values recommended by communal hygiene.
    Keywords: BIOTECHNOLOGY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 212-217
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  • 5
    Publication Date: 2006-01-11
    Description: There exists a correlation between noise intensity and spectrum and degree of hearing impairment in the different professional categories in the pit. Most affected are dross miners and drillers. In these, the first degree of hypoacusia sets in within the first five years of exposure. Deafness begins at a frequency of 4,000 Hz, but often enough (20%) at 2,000 Hz as well, progressively evolving through the classical stages if exposure to noise continues. In the coal bearing basins investigated, the noise level is, on the whole, 31.2%, but the conventional zone is not involved by more than 6.3%. Technological and medical measures are proposed for the purpose of avoiding these troubles in the future.
    Keywords: BIOTECHNOLOGY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 170-176
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  • 6
    Publication Date: 2006-01-11
    Description: Several methods of transfer and processing of data whose practical implementation requires operational memory devices are described. Devices incorporating multistable elements are proposed and their main parameters are given. The possibility of using the proposed devices for storing information for transmission in space radio communications channels is examined.
    Keywords: COMMUNICATIONS
    Type: Space Res. in the Ukraine, No. 3 (NASA-TT-F-15537); p 155-162
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  • 7
    Publication Date: 2006-01-11
    Description: The work consists of two parts. The first deals with the fine structure of radio pulses. Based on kinetic theory, processes occurring in the plasma shell of a pulsar when external electromagnetic radiation is present are investigated. It is shown that electromagnetic waves cause electrons to drift relative to ions, and initiate longitudinal oscillations. A dispersion equation describing the longitudinal oscillations in magnetized plasma is derived. Conditions for excitation of oscillations are found. Correlation functions of electron density are calculated, along with the coefficients of electromagnetic wave scattering. It is shown that variations in the amplitude of pulsar pulses are associated with scintillations caused by fluctuations in the plasma electron density. The second part of the study presents a mechanism for the radio emission of pulsars. The model of a rotating and a pulsating star, a neutron star with dipolar or more complex magnetic field, is examined.
    Keywords: COMMUNICATIONS
    Type: Space Res. in the Ukraine, No. 3, (NASA-TT-F-15537); p 44-53
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  • 8
    Publication Date: 2006-01-11
    Description: The effects of the troposphere on arrival time, range, and range rate measurement of radio signals propagating from spacecraft are examined. A tropospheric calibration model which takes into account seasonal variations, various elevations, and apparent location changes was developed. A comparison was made of the effects before and after calibration. Without calibration, a 16-m change in the distance off the spin axis, is induced for a 10-deg minimum elevation symmetrical pass. Even after calibration with the old model, the error in spin axis is still greater than 1 m. Calibration results and estimated uncertainties of the model are given in tabular form. Test results also show that the model met the required accuracy for the Mariner Mars 1971 mission.
    Keywords: COMMUNICATIONS
    Type: Tracking System Analytic Calibration Activities for the Mariner Mars 1971 Mission; p 61-76
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  • 9
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    Publication Date: 2011-08-16
    Description: Expressions are developed for the gain of a centrally obscured, circular optical antenna used as the collecting and focusing optics in a laser receiver, involving losses due to (1) incoming light blockage by central obscuration, (2) energy spillover at the detector, and (3) the effect of local oscillator distribution in the case of heterodyne or homodyne detection. Numerical results are presented for direct detection and for three types of local oscillator distribution (uniform, Gaussian, and matched).
    Keywords: COMMUNICATIONS
    Type: Applied Optics; 13; Oct. 197
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  • 10
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    Publication Date: 2011-08-16
    Description: The gain of centrally obscured optical transmitting antennas is analyzed in detail. The calculations, resulting in near- and far-field antenna gain patterns, assume a circular antenna illuminated by a laser operating in the TEM-00 mode. A simple polynomial equation is derived for matching the incident source distribution to a general antenna configuration for maximum on-axis gain. An interpretation of the resultant gain curves allows a number of auxiliary design curves to be drawn that display the losses in antenna gain due to pointing errors and the cone angle of the beam in the far field as a function of antenna aperture size and its central obscuration. The results are presented in a series of graphs that allow the rapid and accurate evaluation of the antenna gain which may then be substituted into the conventional range equation.
    Keywords: COMMUNICATIONS
    Type: Applied Optics; 13; Sept
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  • 11
    Publication Date: 2011-08-16
    Description: An analytical method is presented for determining the oxygen consumption rate of the intact heart working (as opposed to empty but beating) human left ventricle. Use is made of experimental recordings obtained for the chamber pressure and the associated dimensions of the LV. LV dimensions are determined by cineangiocardiography, and the chamber pressure is obtained by means of fluid-filled catheters during retrograde or transeptal catheterization. An analytical method incorporating these data is then employed for the evaluation of the LV coronary oxygen consumption in five subjects. Oxygen consumption for these subjects was also obtained by the conventional clinical method in order to evaluate the reliability of the proposed method.
    Keywords: BIOTECHNOLOGY
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  • 12
    Publication Date: 2011-08-16
    Description: Methods are described for calculating left ventricular (LV) dimensions and chamber volumes from radiographic films. The use of biplane films for the calculation of LV volume and volume change is based on the assumption of an ellipsoidal geometry. Calculation of LV volumes from biplane films usually overestimated known volumes in postmortem hearts regardless of the methods used for volume calculation. The reasons for this are probably best explained by the fact that a smooth-surface ellipse is used to represent the irregular cavity of the LV chamber. LV volume calculated from data in a single plane compared favorably and closely with volumes calculated from biplane films. A table of normal values of ventricular volume established by angiographic studies is presented.
    Keywords: BIOTECHNOLOGY
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  • 13
    Publication Date: 2016-03-07
    Description: Recent studies concerning the basic physiological and biochemical principles underlying cardiac muscle contraction, methods for the assessment of cardiac function in the clinical situation, and mathematical approaches to cardiac mechanics are presented. Some of the topics covered include: cardiac ultrastructure and function in the normal and failing heart, myocardial energetics, clinical applications of angiocardiography, use of echocardiography for evaluating cardiac performance, systolic time intervals in the noninvasive assessment of left ventricular performance in man, evaluation of passive elastic stiffness for the left ventricle and isolated heart muscle, a conceptual model of myocardial infarction and cardiogenic shock, application of Huxley's sliding-filament theory to the mechanics of normal and hypertrophied cardiac muscle, and a rheological modeling of the intact left ventricle. Individual items are announced in this issue.
    Keywords: BIOTECHNOLOGY
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  • 14
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    Publication Date: 2011-08-16
    Description: An equation representing man's thermal balance under water is considered. The equation states that the body thermal loading from metabolic heat production and artificial heat input must be offset by respiratory and environmental heat exchange to maintain a constant body temperature. Critical body regions are affected by cold-water thermal stress. A model of the thermoregulatory system may be divided into the physical-controlled system and the dynamic controlling system. The thermal model is simulated by computer programs.
    Keywords: BIOTECHNOLOGY
    Type: Annals of Biomedical Engineering; 2; 1974
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  • 15
    Publication Date: 2011-08-16
    Description: An attempt is made to develop mathematical formulas to provide the basis for the design of pseudorandom signals intended for applications requiring accurate knowledge of the statistics of the signals. The analysis approach involves calculating the first five central moments of the weight distribution of subsequences of hybrid-sum sequences. The hybrid-sum sequence is formed from the modulo-two sum of k maximum length sequences and is an extension of the sum sequences formed from two maximum length sequences that Gilson (1966) evaluated. The weight distribution of the subsequences serves as an approximation to the filtering process. The basic reason for the analysis of hybrid-sum sequences is to establish a large group of sequences with good statistical properties. It is shown that this can be accomplished much more efficiently using the hybrid-sum approach rather than forming the group strictly from maximum length sequences.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Communications; COM-22; Aug. 197
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  • 16
    Publication Date: 2011-08-16
    Description: A biothermal model with a physically-controlled subsystem and a dynamically-controlled subsystem is developed to simulate the thermoregulatory system of man under immersed conditions. The model is consistent with experimental data for seminude subjects immersed to neck in cool to temperate water and for 'wet-suited' subjects immersed to neck in cold water. Equations are derived for predicting body temperatures under various dive conditions.
    Keywords: BIOTECHNOLOGY
    Type: Journal of Hydronautics; 8; July 197
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  • 17
    Publication Date: 2011-08-16
    Description: As Pioneer 10 approaches the planet Jupiter, its trajectory will carry it behind the planet, as seen from the earth. The microwave telemetry signal from the spacecraft will then pass through the Jovian atmosphere on its way to the earth, and analysis of the effects of the atmosphere on the signal should yield information on the atmospheric structure. To help define the capabilities of this experiment and to aid the analysis of the real data, we have simulated the occultation experiment on a computer by using model Jovian atmospheres and a predicted trajectory. The results indicate that the useful depth of penetration of the microwave signal will be governed by ammonia absorption rather than superrefractivity. The experiment is apparently far more sensitive to variations in cloud-top temperature than to variations in the hydrogen-helium ratio. Characteristic 'flashes' in the attenuation record of the signal may yield information on the location of the top of the Jovian convective zone.
    Keywords: COMMUNICATIONS
    Type: Journal of Geophysical Research; 79; May 1
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  • 18
    Publication Date: 2011-08-16
    Description: Presentation and discussion of a clinical report describing asymptomatic multifocal ventricular premature contractions in a professional pilot. He had been taking heavy doses of a systemic decongestant agent, pseudoephedrine, prescribed by a physician. He was taken off the medication, and over the next few days the PVCs became less frequent, then disappeared. It is pointed out that physician's instructions to pilots must be given with the realization that some airmen may follow the instructions too zealously in an attempt to remain on flying status.
    Keywords: BIOTECHNOLOGY
    Type: Aerospace Medicine; 45; May 1974
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  • 19
    Publication Date: 2011-08-16
    Keywords: BIOTECHNOLOGY
    Type: Aerospace Medicine; 45; May 1974
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  • 20
    Publication Date: 2011-08-16
    Description: Equations are presented for the calculation of the interelement mutual coupling in a finite-size planar array of waveguide-fed apertures in an infinite flat conductor. The general mutual admittance expression is evaluated for circular apertures, and the mutual coupling calculations are verified experimentally for two Te-(11) mode excited apertures. Qualitative agreement between calculations for a 183-element array and an infinite array establishes the validity of the finite-array theoretical model.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Antennas and Propagation; AP-22; Mar. 197
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  • 21
    Publication Date: 2011-08-16
    Description: A technique is reported for simulating the signal fading that will be experienced by typical optical communication systems. The desired irradiance or amplitude fading statistics can be simulated by incorporating a linearized optical modulator subsystem between the transmitter and receiver. This technique has been implemented in the design and construction of a laboratory channel simulator. The design of the processing electronics is discussed along with the results of tests performed for each mode of operation.
    Keywords: COMMUNICATIONS
    Type: Applied Optics; 13; June 197
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  • 22
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    Publication Date: 2011-08-16
    Description: Precise measurement and spacecraft tracking are obtained by using phase-locked loops in cascade in two-way communications links. Statistics on cycle slip time are of vital importance in system planning and design. This paper presents: (1) results of a computer simulation study of the mean time to first cycle slip of cascade phase-locked loops preceded by bandpass limiters, and (2) the determination of probability distributions of cycle slip. Numerical results are obtained for a typical coherent communication system.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Aerospace and Electronic Systems; AES-10; May 1974
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  • 23
    Publication Date: 2011-08-16
    Keywords: BIOTECHNOLOGY
    Type: Aerospace Medicine; 45; Apr. 197
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  • 24
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    Publication Date: 2011-08-16
    Description: An experimental investigation of bistatic scatter from rain was conducted, using a 143-km scatter path at frequencies of 4.5 and 7.7 GHz. The ratio of transmitted to received power (transmission loss) was measured for scattering angles ranging from 6 to 130 deg. Simultaneous weather radar observations were made at a frequency of 1.3 GHz. Transmission loss estimates for the bistatic scatter path were computed, using the weather radar data, the bistatic radar equation, and a model for the scattering cross section per unit volume of rain based upon Rayleigh scattering by an ensemble of water spheres. The measured and estimated transmission loss values were compared to test the use of the scattering model for the estimation of interference. The averaged ratio of measured-to-calculated transmission loss for the 4.5 GHz data is 1.2 plus or minus 0.4 dB. The averaged ratio for the 7.7 GHz data is -1.6 plus or minus 0.5 dB.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Antennas and Propagation; AP-22; Mar. 197
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  • 25
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    Publication Date: 2011-08-16
    Description: A battery of 11 body balance tests was administered to 7 men before and after 14 days of bedrest. Seven men who had not undergone bed rest served as controls. During bed rest, each subject underwent daily either isotonic, isometric, or no leg exercise. The results showed that, for the bed-rested no exercise, isotonic exercise, and isometric exercise groups, 2 weeks of bed rest produces significant body balance decrements on 3, 4, and 5 of the 11 tests, respectively. Daily leg exercise did not prevent the debilitating effects of bed rest on body balance. After bed rest, balance skill was relearned rapidly so that in most tests, performance had reached prebed-rest levels by the third recovery day. These data suggest that balance impairment is not due to loss of muscular strength in the legs but, perhaps, to a bed-rest-related change in the neurally coded information to postural control centers.
    Keywords: BIOTECHNOLOGY
    Type: Journal of Applied Physiology; 36; Mar. 197
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  • 26
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    Publication Date: 2011-08-16
    Description: A dynamic optometer that electronically records the position of the anterior surface of the human lens is described. The geometrical optics of the eye and optometer, and the scattering of light from the lens, are closely examined to determine the optimum conditions for adjustment of the instrument. The light detector and associated electronics are also considered, and the operating conditions for obtaining the best signal-to-noise ratio are determined.
    Keywords: BIOTECHNOLOGY
    Type: Optical Society of America; vol. 64
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  • 27
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    Publication Date: 2011-08-16
    Description: A quantitative study of internal torsion in the entire tibial bone was performed by using strain gauges to measure the amount of deformation occuring at different locations. Comparison of strain measurements with physical dimensions of the bone produced the modulus of rigidity and its behavior under increased torque. Computerized analysis of the stress distribution shows that more strain occurs near the torqued ends of the bones where also most of the twisting and fracturing takes place.
    Keywords: BIOTECHNOLOGY
    Type: NASA. Goddard Space Flight Center Summer Inst. in Biomed. Eng., 1973; 23 p
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  • 28
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    Publication Date: 2011-08-16
    Description: The design of an infant weight scale is reported that fits into an isolette without disturbing its controlled atmosphere. The scale platform uses strain gages to measure electronically deflections of cantilever beams positioned at its four corners. The weight of the infant is proportional to the sum of the output voltages produced by the gauges on each beam of the scale.
    Keywords: BIOTECHNOLOGY
    Type: NASA. Goddard Space Flight Center Summer Inst. in Biomed. Eng., 1973; 15 p
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  • 29
    Publication Date: 2011-08-16
    Description: An experimental test design is outlined to separate feelers from hearers in the evaluation of persons with varying degrees of hearing impairments. Speech envelope cues are derived from a white noise device containing filters for different frequencies that produce speech awareness thresholds.
    Keywords: BIOTECHNOLOGY
    Type: NASA. Goddard Space Flight Center Summer Inst. in Biomed. Eng., 1973; 6 p
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  • 30
    Publication Date: 2011-08-16
    Description: A speech modulated white noise device is reported that gives the rhythmic characteristics of a speech signal for intelligible reception by deaf persons. The signal is composed of random amplitudes and frequencies as modulated by the speech envelope characteristics of rhythm and stress. Time intensity parameters of speech are conveyed through the vibro-tactile sensation stimuli.
    Keywords: BIOTECHNOLOGY
    Type: NASA. Goddard Space Flight Center Summer Inst. in Biomed. Eng., 1973; 12 p
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  • 31
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    Publication Date: 2011-08-16
    Description: The gathering of surface potential profiles by computerized processing of electrocardiogram data is projected. These profiles are concerned with the detail of localized potentials on the human body and are obtained by voltages plotted against electrode positions with time as the variable held constant. Sample and hold circuits are considered for processing the multiplexed signal and to digitize and code it for the tape recorder.
    Keywords: BIOTECHNOLOGY
    Type: NASA. Goddard Space Flight Center Summer Inst. in Biomed. Eng., 1973; 15 p
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  • 32
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    Publication Date: 2011-08-16
    Description: Theoretical and experimental work for a systems analysis approach to the problem of surgical suit exhaust systems centered on evaluation of halothane absorbing filters. An activated charcoal-alumina-charcoal combination proved to be the best filter for eliminating halothane through multilayer absorption of gas molecules.
    Keywords: BIOTECHNOLOGY
    Type: NASA. Goddard Space Flight Center Summer Inst. in Biomed. Eng., 1973; 24 p
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  • 33
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    Publication Date: 2011-08-16
    Description: A laser satellite ranging system that is mounted upon and integrated with a microwave tracking radar is reported. The 1-pulse/sec ruby laser transmitter is attached directly to the radar's elevation axis and radiates through a new opening in the radar's parabolic dish. The laser photomultiplier tube receiver utilizes the radar's existing 20-cm diam f/11 boresight telescope and observes through a similar symmetrically located opening in the dish. The laser system possesses separate ranging system electronics but shares the radar's timing, computer, and data handling/recording systems. The basic concept of the laser/radar is outlined together with a listing of the numerous advantages over present singular laser range-finding systems. The developmental laser hardware is described along with preliminary range-finding results and expectations.
    Keywords: COMMUNICATIONS
    Type: Applied Optics; 13; Oct. 197
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  • 34
    Publication Date: 2011-08-16
    Description: The application of frequency modulation when constructing a telemetric system in the shortwave band. The operating principles, the construction of the system and the decision making device are described and experimental data are presented. The equipment can be used on sounding balloons.
    Keywords: COMMUNICATIONS
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 59-65
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  • 35
    Publication Date: 2011-08-16
    Description: Expressions which represent the elevation-plane patterns of a large TEM mode coax aperture and a TM-01 mode circular aperture on finite circular and square ground planes have been derived using geometrical theory of diffraction; design curves for the coax case are presented. The expressions for the field pattern were obtained by superposing the infinite ground plane solutions, the first-order diffracted field solutions, and the axial caustic solutions in their respective regions of validity. The pattern analyses for the coax and circular apertures are verified experimentally.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Antennas and Propagation; AP-22; May 1974
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  • 36
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    Publication Date: 2011-08-16
    Description: Diffused optical waveguides are studied using the modal and the ray tracing approach, with an emphasis on the case of a hollow waveguide with diffuse cladding. The properties of the guided modes are investigated in detail. The applications of these structures to optical circuits, integrated optics lasers and capillary gas lasers are discussed.
    Keywords: COMMUNICATIONS
    Type: vol. 43; July 197
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  • 37
    Publication Date: 2011-08-16
    Keywords: BIOTECHNOLOGY
    Type: Applied Microbiology; 27; Mar. 197
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  • 38
    Publication Date: 2011-08-16
    Description: The objectives of the Apollo 17 Lunar Sounder Experiment (ALSE) were to detect subsurface geologic structures, to generate a continuous lunar profile, and to image the moon at radar wavelengths. A three-wavelength synthetic-aperture radar (SAR) operating at 60, 20, and 2 m wavelengths was designed to attain these objectives. The design choices reflected a balance of scientific requirements versus Apollo mission and hardware constraints. The radar data from the lunar mission were recorded on photographic film in a conventional SAR format, and were returned to earth for processing. A combination of optical and digital processing and exploitation techniques was applied to the scientific interpretation of the data. Some preliminary results from the lunar mission have been obtained.
    Keywords: COMMUNICATIONS
    Type: IEEE; vol. 62
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  • 39
    Publication Date: 2011-08-16
    Description: Equations are presented for the calculation of the interelement mutual coupling in a finite size planar array of wave-guide-fed apertures in an infinite flat conductor. The general mutual admittance expression is evaluated for circular apertures and the mutual coupling calculations are verified experimentally for two TE11 mode excited apertures. Qualitative agreement between calculations for a 183 element array and an infinite array establishes the validity of the finite array theoretical model.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Antennas and Propagation; AP-22; Mar. 197
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  • 40
    Publication Date: 2011-08-16
    Keywords: BIOTECHNOLOGY
    Type: Medical and Biological Engineering; 12; May 1974
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  • 41
    Publication Date: 2011-08-16
    Description: The crew members on the last seven Apollo flights observed light flashes that are tentatively attributed to cosmic ray nuclei (atomic number equal to or greater than 6) penetrating the head and eyes of the observers. Analyses of the event rates for all missions has revealed an anomalously low rate for transearth coast observations with respect to translunar coast observations.
    Keywords: BIOTECHNOLOGY
    Type: Science; 183; Mar. 8
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  • 42
    Publication Date: 2019-06-27
    Description: A digital simulation is presented for a candidate modem in a modeled atmospheric scintillation environment with Doppler, Doppler rate, and signal attenuation typical of the radio link conditions for an outer planets atmospheric entry probe. The results indicate that the signal acquisition characteristics and the channel error rate are acceptable for the system requirements of the radio link. The simulation also outputs data for calculating other error statistics and a quantized symbol stream from which error correction decoding can be analyzed.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-114739
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  • 43
    Publication Date: 2019-06-27
    Description: Surface electromyograms (EMG) taken from three upper torso muscles during a push-pull task were analyzed by a power spectral density technique to determine the utility of the spectral analysis for identifying changes in the EMG caused by muscular fatigue. The results confirmed the value of the frequency analysis for identifying fatigue producing muscular performance. Data revealed reliable differences between muscles in fatigue induced responses to various locations in the reach envelope at which the subjects were required to perform the push-pull exercise, and the differential sensitivity of individual muscles to the various reach positions; i.e., certain reach positions imposed more fatigue related shifts in EMG power than did others. It was found that a pressurized space suit changed the pattern of normal shirtsleeve muscle fatigue responses in all three of the muscles.
    Keywords: BIOTECHNOLOGY
    Type: NASA-TM-X-58136 , JSC-09004
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  • 44
    Publication Date: 2019-06-27
    Description: Parts lists for the 2.25 GHz indoor- and antenna-unit assemblies are followed by drawings that constitute the drafting package for three converter types and the tunnel diode amplifier.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-120933
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  • 45
    Publication Date: 2019-06-27
    Description: A frequency modulated (FM) multiplexer, consisting of 21 IRIG-A constant bandwidth (CBW) voltage-controlled oscillators (VCO's) was tested to determine its suitability for use in multiplexing 21 data signals which have frequency ranges of dc to 2 kHz. Tests were preformed with the composite signal, consisting of the mixed outputs of the 21 VCO's connected directly to a set of subcarrier discriminators, with the signal recorded on magnetic tape and played back through the discriminators and with the signal transmitted by a frequency-modulated FM S-band radio frequency RF transmitter to a FM receiver and through the subcarrier discriminators. Tape speed flutter was induced to determine the reduction in flutter noise which can be obtained by the tape speed compensation equipment. The RF transmission test included transmitting the composite signal at a nominal RF received signal of -73 dbm and at RF levels of -83 and -86 dbm.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-134304 , LEC-3558 , JSC-09017
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  • 46
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    In:  CASI
    Publication Date: 2019-06-27
    Description: Variations in total inertia and gravity loads at the joint outputs are treated along with the relative importance of gravity and acceleration-generated reaction torques or forces versus inertia torques or forces. The relation between the dynamical state equations in explicit terms and servoing the manipulator is briefly discussed in the framework of state variable feedback control which also forms the basis of adaptive manipulator control. Exact state equations were determined for total inertia and gravity loads at the joint outputs as a function of joint variables, using the constant inertial and geometric parameters of the individual links defined in the respective link coordinate frames. The range of maximum variations in total inertia and gravity loads at the joint outputs was calculated for both no load and load in the hand. The main result is the construction of a set of greatly simplified state equations which describe the total inertia and gravity load variations at the output of the six joints with an average error of less than 5%.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-136935 , JPL-TM-33-669
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  • 47
    Publication Date: 2019-06-27
    Description: An atmosphere control subsystem (ACS) was developed for NASA-IBJSC which is designed to measure the major atmospheric constituents in the manned cabin of the space shuttle orbiter and control the addition of oxygen and nitrogen to maintain the partial pressures of these gases within very close limits. The ACS includes a mass spectrometer sensor (MSS) which analyzes the atmosphere of a shuttle vehicle pressurized cabin, and an electronic control assembly (ECA). The MSS was built and tested to meet the requirements for flight equipment for the M-171 Metabolic Analyzer experiment for the Skylab flight program. The instrument analyzes an atmospheric gas sample and produces continuous 0-5 vdc analog signals proportional to the partial pressures of H2, O2, N2, H2O, CO2 and total hydrocarbons having a m/e ratio between 50 and 120. It accepts signals from the MSS proportional to the partial pressures of N2 and O2 and controls the supply of these gases to the closed cabin.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-134190 , MDC-G4971
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  • 48
    Publication Date: 2019-06-27
    Description: The development of a completely heat sterilizable intermittent positive pressure breathing (IPPB) ventilator in an effort to reduce the number of hospital acquired infections is reported. After appropriate changes in materials and design were made, six prototype units were fabricated and were successfully field tested in local hospitals. Most components of the modified ventilators are compatible with existing machines. In all but a few instances, such as installation of bacteria-retentive filters and a modified venturi, the change over from non-heat-sterilizable to sterilizable units was accomplished by replacement of heat labile materials with heat stable materials.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-136832 , JPL-TM-33-670
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  • 49
    Publication Date: 2019-06-27
    Description: Studies on the digital communication system for the direct communication links from ground to space shuttle and the links involving the Tracking and Data Relay Satellite (TDRS). Three main tasks were performed:(1) Channel encoding/decoding parameter optimization for forward and reverse TDRS links,(2)integration of command encoding/decoding and channel encoding/decoding; and (3) modulation coding interface study. The general communication environment is presented to provide the necessary background for the tasks and to provide an understanding of the implications of the results of the studies.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-134183 , R7401-2
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  • 50
    Publication Date: 2019-06-27
    Keywords: BIOTECHNOLOGY
    Type: Journal of Applied Physiology; 37; Aug. 197
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  • 51
    Publication Date: 2019-06-27
    Description: A formulation is given for the correlation functions for the log-amplitude and phase fluctuations of both spherical and plane waves propagating in a turbulent medium whose correlation function for refractive index fluctuations is described by the product of a function of the average coordinate and a function of the difference coordinate. The results are applied to radio occultation of a flyby space probe by the atmosphere of Venus, assuming that the turbulence in the atmosphere exists as a layer, that it is localized, isotropic, and smoothly varying, and that the localized turbulence is described by the Kolmogorov spectrum. Closed-form solutions for both variances and frequency spectra of the log-amplitude and phase fluctuations are obtained using Rytov's method, and it is seen that the shape of the frequency spectra depends greatly on the characteristics and extent of the turbulence.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Antennas and Propagation; AP-22; July 197
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  • 52
    Publication Date: 2019-06-27
    Keywords: COMMUNICATIONS
    Type: Journal of Atmospheric and Terrestrial Physics; 36; May 1974
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  • 53
    Publication Date: 2019-06-27
    Description: Corrugated horns involve a junction between the corrugated surface and a conducting ground plane. Proper horn design requires an understanding of the electromagnetic properties of the corrugated surface and this junction. An integral equation solution has been used to study the influence of corrugation density and tooth thickness on the power loss, surface current, and the scattering from a ground plane/corrugated surface junction.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Antennas and Propagation; AP-22; Mar. 197
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  • 54
    Publication Date: 2019-06-27
    Description: An electrooptical head-position monitoring system was designed and built and is used in single-axis and three-axis 'hands-off' control tasks. The monitor consists of a transparent plexiglass body-fixed helmet provided with a set of eight silicon photodetectors sensing pitch, roll, and yaw motions of the head. Two light-emitting diodes, attached to the pilot's helmet liner, provide the ac modulated near infrared radiation. Head control is compared with conventional manual control for single-axis and three-axis tracking tasks. Both performance curves and describing functions are presented.
    Keywords: BIOTECHNOLOGY
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  • 55
    Publication Date: 2019-06-27
    Description: Frequency bands that best discriminate the Korotkov sounds at systole and at diastole from the sounds immediately preceding these events are defined. Korotkov sound data were recorded from five normotensive subjects during orthostatic stress (lower body negative pressure) and bicycle ergometry. A spectral analysis of the seven Korotkov sounds centered about the systolic and diastolic auscultatory events revealed that a maximum increase in amplitude at the systolic transition occurred in the 18-26-Hz band, while a maximum decrease in amplitude at the diastolic transition occurred in the 40-60-Hz band. These findings were remarkably consistent across subjects and test conditions. These passbands are included in the design specifications for an automatic blood pressure measuring system used in conjuction with medical experiments during NASA's Skylab program.
    Keywords: BIOTECHNOLOGY
    Type: IEEE Transactions on Biomedical Engineering; BME-21; Mar. 197
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  • 56
    Publication Date: 2019-06-27
    Keywords: BIOTECHNOLOGY
    Type: IEEE Transactions on Biomedical Engineering; BME-21; Mar. 197
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  • 57
    Publication Date: 2019-06-27
    Description: Pitch and roll plane radiation patterns computed by use of an integral equation formulation are presented for a space shuttle annular slot communications antenna. The excellent agreement between computed patterns and experimental patterns obtained from 1/35 scale models supports the use of this method as a design tool for similar spacecraft/aircraft antenna applications.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Antennas and Propagation; AP-22; Jan. 197
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  • 58
    Publication Date: 2019-06-27
    Description: The purpose of the membrane water deaerator program was to develop data on a breadboard hollow fiber membrane unit that removes both dissolved and evolved gas from a water transfer system in order to: (1) assure a hard fill of the EVLSS expendable water tank; (2) prevent flow blockage by gas bubbles in circulating systems; and (3) prevent pump cavitation.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-140259 , AIRESEARCH-74-10072
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  • 59
    Publication Date: 2019-06-27
    Description: The functional requirements of stowage, preparation, serving, consumption, and cleanup were applied to each of the five food mixes selected for study in terms of the overall design of the space shuttle food system. The analysis led to a definition of performance requirements for each food mix, along with a definition of equipment to meet those requirements. Weight and volume data for all five systems, in terms of food and packaging, support equipment, and galley installation penalties, are presented.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-134377
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  • 60
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A noise abating improvement for jet engines including turbojets, turbofans, turboprops, ramjets, scramjets, and hybrid jets is introduced. A provision is made for an apparatus in the primary and/or secondary flow streams of the engines; the apparatus imparts to the exhaust gases a component rotation or swirl about the engine's longitudinal axis. The rotary component in the exhaust gases causes a substantial suppression of sound energy build up normally produced by an axial flow exhaust system.
    Keywords: COMMUNICATIONS
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  • 61
    Publication Date: 2019-06-27
    Description: The design, fabrication, and performance of elements of a low cost FM microwave satellite ground station receiver is described. It is capable of accepting 12 contiguous color television equivalent bandwidth channels in the 11.72 to 12.2 GHz band. Each channel is 40 MHz wide and incorporates a 4 MHz guard band. The modulation format is wideband FM and the channels are frequency division multiplexed. Twelve independent CATV compatible baseband outputs are provided. The overall system specifications are first discussed, then consideration is given to the receiver subsystems and the signal branching network.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-140056 , R(T)-74/2
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  • 62
    Publication Date: 2019-06-27
    Description: An S-band antenna system and a group of off-the-shelf aircraft antenna were exposed to temperatures simulating shuttle orbital cold soak and entry heating. Radiation pattern and impedance measurements before and after exposure to the thermal environments were used to evaluate the electrical performance. The results of the electrical and thermal testing are given. Test data showed minor changes in electrical performance and established the capability of these antenna to withstand both the low temperatures of space flight and the high temperatures of entry.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-140226 , MDC-E0896-VOL-2
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  • 63
    Publication Date: 2019-06-27
    Description: The zero gravity test program demonstrated the feasibility and practicability of collecting urine from both male and female crew members in a zero gravity environment in an earthlike manner not requiring any manual handling of urine containers. In addition, the testing demonstrated that a seat which is comfortable in both regimes of operation could be designed for use on the ground and in zero-gravity. Further, the tests showed that the vortex liquid/air separator is an effective liquid/air separation method in zero gravity. Visual observations indicate essentially zero liquid carry over. The system also demonstrated its ability to handle post elimination wipes without difficulty. The designs utilized in the WCS were verified as acceptable for usage in the space shuttle or other space vehicles.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-104240 , SVHSER-6509
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  • 64
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    In:  CASI
    Publication Date: 2019-06-27
    Description: Data were assembled which define the optimum food system to support the space shuttle program, and which provide sufficient engineering data to support necessary requests for proposals towards final development and installment of the system. The study approach used is outlined, along with technical data and sketches for each functional area. Logistic support analysis, system assurance, and recommendations and conclusions based on the study results are also presented.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-134374
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  • 65
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    In:  CASI
    Publication Date: 2019-06-27
    Description: A tuned noise suppressor is described consisting of annular acoustically porous elements for incorporation into the inlet and exhaust ducts of turbofan engines. The apparatus uses sound wave absorption, reflection, and incompatibility for achieving high noise reduction in the short distance. In addition, it has a duct of uniform inner diameter which does not block the duct flow.
    Keywords: COMMUNICATIONS
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  • 66
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    In:  CASI
    Publication Date: 2019-06-27
    Description: The NASA Deep Space Net (DSN) in support of the Viking Mars Project in 1976, and for science and technology demonstrations during the Mariner-Venus-Mercury mission in 1974, has developed and implemented a dual (S- and X-band) feed for large ground microwave antennas. This feed provides for a multiplicity of functions; very low listening capability at each downlink (spacecraft-to-earth) band as well as simultaneous diplexed very high cw power uplink (earth-to-spacecraft) at the S-band frequency. Total 64-m antenna system performance, is considered in terms of gain, operating noise temperature and dual beam pointing or boresight coincidence. Because of the unique ability to fold or stow the dual band feed elements for single band operations, the performance definition between single and dual band operations will be reliable and accurate.
    Keywords: COMMUNICATIONS
    Type: AGARD Antennas for Avionics; 10 p
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  • 67
    Publication Date: 2019-06-27
    Description: Two problems related to the effects of turbulence in the atmosphere of Venus on the Pioneer entry probe radio link were studied. In the first problem, the cross correlation between the log amplitude and phase fluctuations of the Pioneer Venus communications link is examined. Data show that for fluctuation frequencies above approximately 1 Hz there is little or no correlation. For frequencies below this region the correlation is weak and the square root of the coherence has a peak value close to 0.65. The second problem consists of interferring turbulence characteristics of the Venus atmosphere from the Mariner 5 phase fluctuations. Data show that with the data processing techniques developed and currently available, the phase error due to oscillator drift, assumed trajectory delay, and spline curve fit exceed the turbulence induced fluctuations. Results show that it is not possible to interfere with the turbulence characteristics from Mariner 5 phase fluctuations.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-139657 , JPL-TM-33-702
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  • 68
    Publication Date: 2019-06-27
    Description: A study of the use of newly emerging communications technology for improving the understanding between members of Congress and their constituents was conducted. The study employed a number of specific methodologies such as interdisciplinary systems model building, technology analysis, a sample survey, and semi-structured interviews using sketches of the emergent channels. The following configurations were identified as representative of emergent channel characteristics: (1) the teleconference, (2) the videoconference, (3) the videophone, (4) cable television, (5) cable television polling, and (6) information retrieval. Analysis of the interview data resulted in an overview of the current congressional-constituent communication system and an assessment of the potential for emergent telecommunications, as perceived by congressmen and senior staff from 40 offices in the stratified judgement sample.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-139669 , GWPS-MON-20
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  • 69
    Publication Date: 2019-06-27
    Description: Disinfection and corrosion control in the water systems of the Saturn 5 Orbital Workshop Program are considered. Within this framework, the problem areas of concern are classified into four general areas: disinfection; corrosion; membrane-associated problems of disinfectant uptake and diffusion; and taste and odor problems arising from membrane-disinfectant interaction.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-140197
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  • 70
    Publication Date: 2019-06-27
    Description: The identification of required data for studies of Spacelab experiment functional allocation, the development of an approach to collecting these data from the payload community, and the specification of analytical methods necessary to quantitatively determine the role of man in specific Spacelab experiments are presented. A generalized Spacelab experiment operation sequence was developed, and the parameters necessary to describe each signle function in the sequence were identified. A set of functional descriptor worksheets were also drawn up. The methodological approach to defining the role of man was defined as a series of trade studies using a digial simulation technique. The tradeoff variables identified include scientific crew size, skill mix, and location. An existing digital simulation program suitable for the required analyses was identified and obtained.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-120398
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  • 71
    Publication Date: 2019-06-27
    Description: The teleoperator system man-machine interface evaluation develops and implements a program to determine human performance requirements in teleoperator systems.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-139598 , H-4-1
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  • 72
    Publication Date: 2019-06-27
    Description: A choking device to cause a sonic barrier to be formed which reduces the transmission of noise in a direction opposed to the direction of air flow in a compressor that may be part of an aircraft gas turbine engine is described. The noise reduction is accomplished by proper shaping and movement of inlet guide vanes, and an actuator is connected to selected guide vanes to effect movement by programmed amounts as required to choke or partially choke within the design range of the axial-flow-air compressor.
    Keywords: COMMUNICATIONS
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  • 73
    Publication Date: 2019-06-27
    Description: The primary function of the study was to assess the impact upon the HEAO telecommunications system of the proposed relay satellite-to-ground-link configuration. The system is designed to perform the function of most of the NASA ground tracking and communications network at a net cost savings for NASA.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-139393
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  • 74
    Publication Date: 2019-06-27
    Description: Special purpose satellites are very cost sensitive to the number of broadcast channels, usually will have Poisson arrivals, fairly low utilization (less than 35%), and a very high availability requirement. To solve the problem of determining the effects of limiting C the number of channels, the Poisson arrival, infinite server queueing model will be modified to describe the many server case. The model is predicated on the reproductive property of the Poisson distribution.
    Keywords: COMMUNICATIONS
    Type: NASA-TM-X-71590
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  • 75
    Publication Date: 2019-06-27
    Description: The research to design, fabricate, test, and deliver a pressure vessel for the main component in an improved high-performance firefighter's breathing system is reported. The principal physical and performance characteristics of the vessel which were required are: (1) maximum weight of 9.0 lb; (2) maximum operating pressure of 4500 psig (charge pressure of 4000 psig); (3) minimum contained volume of 280 in. 3; (4) proof pressure of 6750 psig; (5) minimum burst pressure of 9000 psig following operational and service life; and (6) a minimum service life of 15 years. The vessel developed to fulfill the requirements described was completely sucessful, i.e., every category of performence was satisfied. The average weight of the vessel was found to be about 8.3 lb, well below the 9.0 lb specification requirement.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-134384 , MCR-73-214
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  • 76
    Publication Date: 2019-06-27
    Description: The capabilities for preflight feeding of flight personnel and the supply and control of the space shuttle flight food system were investigated to determine ground support requirements; and the functional details of an onboard food system galley are shown in photographic mockups. The elements which were identified as necessary to the efficient accomplishment of ground support functions include the following: (1) administration; (2) dietetics; (3) analytical laboratories; (4) flight food warehouse; (5) stowage module assembly area; (6) launch site module storage area; (7) alert crew restaurant and disperse crew galleys; (8) ground food warehouse; (9) manufacturing facilities; (10) transport; and (11) computer support. Each element is discussed according to the design criteria of minimum cost, maximum flexibility, reliability, and efficiency consistent with space shuttle requirements. The galley mockup overview illustrates the initial operation configuration, food stowage locations, meal assembly and serving trays, meal preparation configuration, serving, trash management, and the logistics of handling and cleanup equipment.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-134379
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  • 77
    Publication Date: 2019-06-27
    Description: The analysis and selection of food items and primary packaging, the development of menus, the nutritional analysis of diet, and the analyses of alternate food mixes and contingency foods is reported in terms of the overall food system design for space shuttle flight. Stowage weights and cubic volumes associated with each alternate mix were also evaluated.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-134378
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  • 78
    Publication Date: 2019-06-27
    Description: A six man, self contained, electrochemical carbon dioxide concentrating subsystem for space station prototype use was successfully designed, fabricated, and tested. A test program was successfully completed which covered shakedown testing, design verification testing, and acceptance testing.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-114742 , LSI-ER-170-34
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  • 79
    Publication Date: 2019-06-27
    Description: The relative penalties associated with various techniques for providing an onboard cold environment for storage of perishable food items, and for the development of packaging and vehicle stowage parameters were investigated in terms of the overall food system design analysis of space shuttle. The degrees of capability for maintaining both a 40 F to 45 F refrigerated temperature and a 0 F and 20 F frozen environment were assessed for the following cooling techniques: (1) phase change (heat sink) concept; (2) thermoelectric concept; (3) vapor cycle concept; and (4) expendable ammonia concept. The parameters considered in the analysis were weight, volume, and spacecraft power restrictions. Data were also produced for packaging and vehicle stowage parameters which are compatible with vehicle weight and volume specifications. Certain assumptions were made for food packaging sizes based on previously generated space shuttle menus. The results of the study are shown, along with the range of meal choices considered.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-134376
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  • 80
    Publication Date: 2019-06-27
    Description: Technical data are presented which were used to evaluate active heating methods to be incorporated into the space shuttle food system design, and also to evaluate the relative merits and penalties associated with various approaches to the heating of rehydrated food during space flight. Equipment heating candidates were subject to a preliminary screening performed by a selection rationale process which considered the following parameters; (1) gravitational effect; (2) safety; (3) operability; (4) system compatibility; (5) serviceability; (6) crew acceptability; (7) crew time; (8) development risk; and (9) operating cost. A hot air oven, electrically heated food tray, and microwave oven were selected for further consideration and analysis. Passive, semi-active, and active food preparation approaches were also studied in an effort to determine the optimum method for heating rehydrated food. Potential complexity, cost, vehicle impact penalties, and palatability were considered in the analysis. A summary of the study results is provided along with cost estimates for each of the potential sytems
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-134375
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  • 81
    Publication Date: 2019-06-27
    Description: Three areas of inquiry are reported for the Skylab Experiment S-071 whose objective was to study the circadian system of a mammal during space flight. The thermoregulatory behavior of the Perognathus longimembris, or little pocket mouse, was studied under conditions of constant dark and constant temperature in the prolonged weightless environment of Skylab. The following specific questions were studied: (1) the effects of weightlessness on circadian periodicity in the little pocket mouse; (2) stability of the free-running circadian period of body temperature of the little pocket mouse exposed to simulated launch stress; and (3) characteristics of the circadian rhythm of body temperature in the little pocket mouse. Diagrams of the electronic circuitry and hardware used in the experiment are shown and results are given in both graphical and tabular form. The methods used in the experiment are fully documented, along with conclusions and recommendations for future research.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-137523
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  • 82
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    In:  CASI
    Publication Date: 2019-06-27
    Description: The system concept and characteristics are described along with support and orbital coverage capabilities. Information on user acquisition procedures is given. System impact on single and multiple access users is discussed.
    Keywords: COMMUNICATIONS
    Type: NASA-TM-X-70710 , X-805-74-176
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  • 83
    Publication Date: 2019-06-27
    Description: An integral equation formulation is applied to predict pitch- and roll-plane radiation patterns of a thin VHF/UHF (very high frequency/ultra high frequency) annular slot communications antenna operating at several locations in the nose region of the space shuttle orbiter. Digital computer programs used to compute radiation patterns are given and the use of the programs is illustrated. Experimental verification of computed patterns is given from measurements made on 1/35-scale models of the orbiter.
    Keywords: COMMUNICATIONS
    Type: NASA-TN-D-7594 , L-9279
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  • 84
    Publication Date: 2019-06-27
    Description: End-to-end system considerations involving channel coding and data compression which could drastically improve the efficiency in communicating pictorial information from future planetary spacecraft are presented.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-139362 , JPL-TM-33-695
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  • 85
    Publication Date: 2019-06-27
    Description: The multipurpose ventricular actuating system is a pneumatic signal generating device that provides controlled driving pressures for actuating pulsatile blood pumps. Overall system capabilities, the timing circuitry, and calibration instruction are included.
    Keywords: BIOTECHNOLOGY
    Type: NASA-TM-X-71570 , E-8009
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  • 86
    Publication Date: 2019-06-27
    Description: A system designed to collect electroencephalographic, electro-oculographic, electromyographic, and head motion data is described. The portable instrumentation provides a rapid and simple means by which neurophysiological data can be obtained by the patient in his home and the taped data returned to the laboratory for analysis. The system was designed primarily for the study of sleep.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-2416
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  • 87
    Publication Date: 2019-06-27
    Description: Application and requirements for remote manipulator systems for future space missions were investigated. A manipulator evaluation program was established to study the effects of various systems parameters on operator performance of tasks necessary for remotely manned missions. The program and laboratory facilities are described. Evaluation criteria and philosophy are discussed.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-120218 , H-4-3
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  • 88
    Publication Date: 2019-06-27
    Description: As part of a larger effort to assess passenger comfort in aircraft, two questionnaires were administered: one to ground-based respondents; the other to passengers in flight. Respondents indicated the importance of various factors influencing their satisfaction with a trip, the perceived importance of various physical factors in determining their level of comfort, and the ease of time spent performing activities in flight. The in-flight sample also provided a rating of their level of comfort and of their willingness to fly again. Comfort ratings were examined in relation to (1) type of respondent, (2) type of aircraft, (3) characteristics of the passengers, (4) ease of performing activities, and (5) willingness to fly again.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-139368 , MEMO-403214
    Format: application/pdf
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  • 89
    Publication Date: 2019-06-27
    Description: The technique which utilizes exposure to a plasma to remove contaminants from a surface was incorporated into a laboratory model which demonstrates active cleaning by both plasma cleaning and ion sputtering modes of operation. The development phase is reported and includes discussion of the plasma tube configuration, device design, and performance tests. A general description of the active cleaning device is provided which includes information on the main power/plasma discharge sensors, and the power, gas supply, and ion accelerator systems. Development of the active cleaning species at high vacuum conditions is described and results indicate that plasma cleaning occurs in the region of a visible plume which extends from the end of the plasma tube. Recommendations are made for research to determine the plasma cleaning mechanism and the plasma species responsible for the cleaning, as well limitations on the type of contaminants that can be removed.
    Keywords: BIOTECHNOLOGY
    Type: NASA-CR-120292 , D180-18031-1
    Format: application/pdf
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  • 90
    Publication Date: 2019-06-27
    Description: An electronic control system for nondissipative dc power converters is presented which improves (1) the routinely attainable static output voltage accuracy to the order of + or - 1% for ambient temperatures from -55 to 100 C and (2) the dynamic stability by utilizing approximately one tenth of the feedback gain needed otherwise. Performance is due to a functional philosophy of deterministic pulse modulation based on pulse area control and to an autocompensated signal processing principle. The system can be implemented with commercially available unselected components.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-134544
    Format: application/pdf
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  • 91
    Publication Date: 2019-06-27
    Description: The theory, computer program, and numerical results of an investigation of an axial slot antenna on a circular cylinder are discussed. The cylinder is partially coated with a dielectric layer and the antenna radiates through a flush mounted window. The study was conducted to determine the effects of a high temperature dielectric layer on the performance of antennas mounted on a space shuttle. Mathematical models are developed to show the relationships of the parameters. Curves are developed to compare the theoretical and actual far field radiation patterns.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-138752 , ESL-2902-17
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  • 92
    Publication Date: 2019-06-27
    Description: Mode conversion in a periodically perturbed thin-film optical waveguide is studied in detail. Three different types of perturbations are considered: periodic index of refraction of the film, periodic index of refraction of the substrate, and periodic boundary. The applications in filters, mode converters, and distributed feedback lasers are discussed.
    Keywords: COMMUNICATIONS
    Type: Journal of Applied Physics; 45; Aug. 197
    Format: text
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  • 93
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-06-27
    Description: Several tables are presented giving left ventricular (LV) data for normal patients and patients with heart disease of varied etiologies, pointing out the salient features. Graphs showing LV pressure-volume relationships (compliance) are presented and discussed. The method developed by Rackley et al. (1964) for determining left ventricular mass in man is described, and limitations to the method are discussed. Some clinical methods for determining LV oxygen consumption are briefly described, and the relation of various abnormalities of ventricular performance to coronary artery disease and ischemic heart disease is characterized.
    Keywords: BIOTECHNOLOGY
    Format: text
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  • 94
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-06-27
    Description: Many recent American unmanned planetary probes have used biorthogonally coded spacecraft-to-earth telemetry links. An examination of the frame-synchronization (sync) techniques employed on these missions revealed that they were not specifically designed for coded data. This led to a consideration of the optimum frame-sync problem for biorthogonally coded data received over the additive white Gaussian noise (AWGN) channel and decoded prior to sync acquisition. A frame-sync algorithm for biorthogonally coded data based on a super-symbol distance rule is proposed, along with a corresponding selection criterion for the sync sequence. It is argued heuristically that this approach is optimum with regard to minimizing the probability of false synchronization.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Communications; COM-22; Aug. 197
    Format: text
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  • 95
    Publication Date: 2019-06-27
    Description: Consideration of the recently observed phenomenon of scintillation of satellite signals at GHz frequency range. Based on the scintillation data and results from in situ measurements, several ionospheric irregularity models with different power spectra are studied. Scintillation index is computed for the various models and compared with observed results. Both magnitude and frequency dependence of the scintillation index are investigated. It is found that a thick irregularity slab of the order of 200 km with an electron density fluctuation of about 20 per cent of its background value and with a nonmonotonic power spectrum may account for the maximum observed values of the scintillation index as well as its frequency dependence. Some future observations and measurements are suggested.
    Keywords: COMMUNICATIONS
    Type: Journal of Atmospheric and Terrestrial Physics; 36; May 1974
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  • 96
    Publication Date: 2019-06-27
    Description: Three male swimmers underwent 10-min resting and 20-min swimming (breaststroke) exposures in a swimming flume. Water temperatures in separate exposures were 18, 26, and 33 C. At each water temperature the subjects rested and swam at water velocities of 0.50, 0.75, and 0.95 m/sec, which were designed to produce around 40, 70, and 100% of maximal aerobic power. Measurements were made of esophageal temperature, four skin temperatures, water temperature, heat flow from five local skin surfaces (Hatfield-Turner disks), and oxygen uptake. Calculations were made of mean area-weighted skin temperature and heat flow, metabolic rate, and heat storage. Internal body temperature changes after 20 min of swimming were related to water temperature, swimming intensity, and body composition.
    Keywords: BIOTECHNOLOGY
    Type: Journal of Applied Physiology; 36; Apr. 197
    Format: text
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  • 97
    Publication Date: 2019-06-27
    Description: Two weeks of continuous exposure to simulated weightlessness (bedrest) and/or an elevated (30 torr) CO2 environment had no detrimental effect on complex tracking performance, eye-hand coordination, or problem-solving ability. These results were consistent with previously reported behavioral findings which investigated these two factors only as independent stressors.
    Keywords: BIOTECHNOLOGY
    Type: AD-778501 , SAM-TR-73-338 , Aerospace Medicine; 45; Apr. 197
    Format: text
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  • 98
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-27
    Description: A feasibility unit suitable for use as a voice recorder on the space shuttle was developed. A modification, development, and test program is described. A LM-DSEA recorder was modified to achieve the following goals: (1) redesign case to allow in-flight cartridge change; (2) time code change from LM code to IRIG-B 100 pps code; (3) delete cold plate requirements (also requires deletion of long-term thermal vacuum operation at 0.00001 MMHg); (4) implement track sequence reset during cartridge change; (5) reduce record time per cartridge because of unavailability of LM thin-base tape; and (6) add an internal Vox key circuit to turn on/off transport and electronics with voice data input signal. The recorder was tested at both the LM and shuttle vibration levels. The modified recorder achieved the same level of flutter during vibration as the DSEA recorder prior to modification. Several improvements were made over the specification requirements. The high manufacturing cost is discussed.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-140305
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  • 99
    Publication Date: 2019-06-27
    Description: A computer program is presented for a thin-wire antenna over a perfect ground plane. The analysis is performed in the frequency domain, and the exterior medium is free space. The antenna may have finite conductivity and lumped loads. The output data includes the current distribution, impedance, radiation efficiency, and gain. The program uses sinusoidal bases and Galerkin's method.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-140622 , Technical Report 2902-19
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  • 100
    Publication Date: 2019-06-27
    Description: End-to-end system considerations involving channel coding and data compression are reported which could drastically improve the efficiency in communicating pictorial information from future planetary spacecraft. In addition to presenting new and potentially significant system considerations, this report attempts to fill a need for a comprehensive tutorial which makes much of this very subject accessible to readers whose disciplines lie outside of communication theory.
    Keywords: COMMUNICATIONS
    Type: NASA-CR-140181 , JPL-TM-33-695-REV-1
    Format: application/pdf
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