Exposure of Escherichia coli to low-frequency vibrations
Low frequency mechanical vibration effects on biochemical mutant formation in E. coli
Beischer, D. E.↗
SEARCH · Engineering Papers
Results for “VIBRATION EFFECT”
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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A method for recording myocardial ECG in animals during intense vibration
Body vibration effects in cats on myocardial ECG recordings, discussing electrodes implantation and tracings
Sass, D. J.↗
Modified bubble level senses pitch and roll angles over wide range
Bubble level sensor with fiber-optic field flattener is simple, rugged, small, and impervious to temperature and vibration effects. Pitch angles from -15 deg to +40 deg and roll angles of +30 deg are determined within 0.5 deg.
Mattson, E. J.↗
Vibration in V/STOL aircraft
Environmental tests of V/STOL vibration effects on human comfort
Jones, W. L.↗
Development of CO2 laser Doppler instrumentation detection of clear air turbulence Appendix D and appendix E, addenda to final report
Clear air turbulence pulse Doppler laser radar design including analysis of mechanical vibration effects on laser transmitter and reciever
Jelalian, A.↗
Research achievements review. Volume 4 - Report no. 1 - Structures research at MSFC
Dynamic structural analysis, statistical analysis, and Rayleigh-Ritz methods applied to Skylab and Apollo/Saturn problems including pogo effects, vibration damping, and noise reduction
Source record↗
Fatigue failure of materials under narrow band random vibrations. II
Material fatigue failure under narrow band random vibration effects, deriving fatigue life prediction equation based on composite experimental design and statistical tests
Huang, T. C.↗
Vibration
Man's reactions to vibration are emphasized rather than his reactions to the vibrational characteristics of vehicles. Vibrational effects studies include: performance effects reflected in tracking proficiency, reaction time, visual impairment, and other measures related to man's ability to control a system; physiological reactions; biodynamic responses; subjective reactions; and human tolerance limits. Technological refinements in shaker systems and improved experimental designs are used to validate the data.
Hornick, R. J.↗
Study and design of cryogenic propellant acquisition systems. Volume 2: Supporting experimental program
Areas of cryogenic fuel systems were identified where critical experimental information was needed either to define a design criteria or to establish the feasibility of a design concept or a critical aspect of a particular design. Such data requirements fell into three broad categories: (1) basic surface tension screen characteristics; (2) screen acquisition device fabrication problems; and (3) screen surface tension device operational failure modes. To explore these problems and to establish design criteria where possible, extensive laboratory or bench test scale experiments were conducted. In general, these proved to be quite successful and, in many instances, the test results were directly used in the system design analyses and development. In some cases, particularly those relating to operational-type problems, areas requiring future research were identified, especially screen heat transfer and vibrational effects.
Burge, G. W.↗
A study of relationships between performance in system tests and space
Approaches for measuring the effectiveness of tests and test programs are considered, taking into account system test effectiveness, thermal-vacuum test effectiveness, and vibration test effectiveness. Methods for predicting space performance on the basis of system test effectiveness are discussed along with aspects of defect detection in thermal-vacuum tests. Questions regarding the thermal-vacuum test costs in relation to the probability of early space failures are also explored.
Timmins, A. R.↗
Photographic Equipment Test System (PETS)
The Photographic Equipment Test System is presented. The device is a mobile optical system designed for evaluating performance of various sensors in a laboratory, in a vacuum chamber or on a flight line. The carriage is designed to allow elevation as well as azimuth control of the direction of the light from the collimator. The pneumatic tires provide an effective vibration isolation system. A target/illumination system is mounted on a motor driven linear slide, and focusing and exposure control can be operated remotely from the small electronics control console.
Source record↗
Performance modeling of earth resources remote sensors
A technique is presented for constructing a mathematical model of an earth resources remote sensor. The technique combines established models of electronic and optical components with formulated models of scan and vibration effects, and it includes a model of the radiation effects of the earth's atmosphere. The resulting composite model is useful for predicting in-flight sensor performance, and a descriptive set of performance parameters is derived in terms of the model. A method is outlined for validating the model for each sensor of interest. The validation for one airborne infrared scanning system is accomplished in part by a satisfactory comparison of predicted response with laboratory data for that sensor.
Kidd, R. H.↗
Air radiation in photographic meteor spectra
Air radiation (N, O, N2) is present in major amounts in the spectra of three high-geocentric-velocity photographic meteor spectra. These spectra are high-definition spectra with over 50 identifiable features in each. These meteor spectra are compared with N2 radiation from a Geissler tube and with calculated N2 first-positive band intensities. An 'effective vibrational temperature' of about 20,000 K is obtained from the nitrogen first-positive band relative intensities. Electron excitation is indicated as the primary excitation process.
Harvey, G. A.↗
Summary of past experience in natural laminar flow and experimental program for resilient leading edge
The potential of natural laminar flow for significant drag reduction and improved efficiency for aircraft is assessed. Past experience with natural laminar flow as reported in published and unpublished data and personal observations of various researchers is summarized. Aspects discussed include surface contour, waviness, and smoothness requirements; noise and vibration effects on boundary layer transition, boundary layer stability criteria; flight experience with natural laminar flow and suction stabilized boundary layers; and propeller slipstream, rain, frost, ice and insect contamination effects on boundary layer transition. The resilient leading edge appears to be a very promising method to prevent leading edge insect contamination.
Carmichael, B. H.↗
Flow-induced Vibration of SSME Main Injector Liquid-oxygen Posts
The liquid-oxygen (LOX) posts are exposed to hot hydrogen flowing over the tubes on its way to the combustion chamber. Fatigue cracking of some LOX posts was observed after test firing of the SSMEs. A current design modification consists of attaching impingement shields to the LOX posts in the outer row. The modification improved the vibration/fatigue problem of the LOX posts, but resulted in an increased pressure drop that ultimately shortened the life expectancy of other components. A fundamental study of vibration of the LOX posts was initiated to understand the flow-induced vibration problem and to develop techniques to avoid detrimental vibrational effects with the overall objective of improving engine life. This effort, including an assessment of the problem, scoping calculation and experiment, and a work plan for an integrated theoretical/experimental study of the problem is summarized.
Chen, S. S.↗
A priori predictions of the rotational constants for protonated formaldehyde and protonated methanol
Protonated formaldehyde and protonated methanol are candidate interstellar molecules and models for classes of protonated oxygen compounds. Ab initio molecular orbital theory has been used to compute rotational constants to guide spectroscopic searches both in the laboratory and in space. The ab initio results are empirically correct to account for systematic deficiencies in the theory and zero-point vibrational effects; they are expected to be accurate to about + or - 2 percent. For H2COH(+) the resultant constants are (in GHz) A = 194.3, B = 34.28, and C = 29.14; for H3COH2(+) A = 103.7, B = 21.18, and C = 20.30.
Defrees, D. J.↗
Active control test on the Mini-Mast
A Linear Quadratic Gaussian (LQG) design process is presented and applied to a large flexible ground test facility, the Mini-Mast, for validation. For the design, nine displacement sensors were used. Three torque wheel actuators were used for damping augmentation. Results were dramatic, indicating an improvement in damping from 3 percent to 30 percent of critical. The tests proved the effectiveness of the procedure in designing effective vibration damping systems.
Montgomery, Raymond C.↗
Utilizing Controlled Vibrations in a Microgravity Environment to Understand and Promote Microstructural Homogeneity During Floating-Zone Crystal Growth
It has been demonstrated in floating-zone configurations utilizing silicone oil and nitrate salts that mechanically induced vibration effectively minimizes detrimental, gravity independent, thermocapillary flow. The processing parameters leading to crystal improvement and aspects of the on-going modeling effort are discussed. Plans for applying the crystal growth technique to commercially relevant materials, e.g., silicon, as well as the value of processing in a microgravity environment are presented.
Grugel, Richard N.↗