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  • Other Sources  (1,202)
  • MACHINE ELEMENTS AND PROCESSES  (1,202)
  • 1970-1974  (1,202)
Collection
  • Maps
  • Other Sources  (1,202)
Source
Keywords
Years
Year
  • 1
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    Noise control of pneumatic percussion drills (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Noise sources in pneumatic drills are studied bringing to light the fact that air exhaust is the most important source. The present state of the art of noise control is discussed for pneumatic percussion drills abroad, indicating the different solutions adopted in this respect. Drills produced in Rumania are described and the results of noise measurements are shown.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 177-181
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  • 2
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    Contributions to the study of the characteristics of bearing noise and vibrations (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Results of experimental research on the noise and vibrations of radial ball and roller bearings are reported. Analysis of the frequency spectra disclosed dependences among vibration and noise, load, rpm and cage material. Some peculiar aspects of the frequency spectrum are also mentioned.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 131-135
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  • 3
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    Aspects of reducing spur gear noise (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Noise sources in gears and ways of improving their silence by profile shape alterations and wheel surface smoothness are discussed. Practical results obtained, from the noise point of view are reported, for textile machinery.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 124-130
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  • 4
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    Contributions to the reduction of gear noise (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The influence of profile displacements on the acoustic pressure level of running gears is studied. The conclusion is reached that extra polar gears function well, reducing the acoustic pressure level by about 2-3 db which, at the level of the total noise of 80-90 db, can be easily felt. This result can be explained by the fact that in this gear the pitch point is situated outside of the gearing segment, so that a certain change in the direction of the friction force between the tooth flanks is eliminated.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 118-123
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  • 5
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    Load influence on gear noise (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: An original mathematical model is proposed to derive equations for calculation of gear noise. These equations permit the acoustic pressure level to be determined as a function of load. Application of this method to three parallel gears is reported. The logical calculation scheme is given, as well as the results obtained.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 112-117
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  • 6
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    Preliminary study of gear noise characteristics (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Experimental results and conclusions are presented about the noise characteristics of gears as a function of their operating conditions. The interpretive possibilities offered by real time noise and vibration spectrum analysis are emphasized. The noise reducing effects of light weight insulation boxes are also discussed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 104-111
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  • 7
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    Considerations on the acoustic energy radiated by toothed gears (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: A mechano-acoustic model is reported for calculating acoustic energy radiated by a working gear. According to this model, a gear is an acoustic coublet formed of the two wheels. The wheel teeth generate cylindrical acoustic waves while the front surfaces of the teeth behave like vibrating pistons. Theoretical results are checked experimentally and good agreement is obtained with open gears. The experiments show that the air noise effect is negligible as compared with the structural noise transmitted to the gear box.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 98-103
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  • 8
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    Acoustic determination of cracks in welded joints (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The acoustic analysis method permits detection of any cracks that might take place and their manner of propagation. The study deals with the cracks produced in experiments to determine the welding technology for a welded gray cast iron workpiece by using piezoelectric transducers to determine vibration acceleration.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 93-97
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  • 9
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    US studies in the field of shaft drilling on the lunar surface (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: American equipment for drilling in the lunar surface is discussed, with emphasis on rotary-percussive methodology and core-sample retrieval techniques.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Current Concepts Regarding the Moon (NASA-TT-F-766); p 192-205
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  • 10
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    Induction brazing at the Kennedy Space Center (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: A description of the joint design, materials, equipment, qualification testing, inspection methods, and applications involved in performing induction brazing on hyperbolic propellants tubing at Kennedy Space Center. Induction brazing is a form of brazing in which the energy is transmitted to the workpiece by electrical induction; the eddy currents generated in the metal produce heat by resistance losses. Since induction heating is fast and highly localized, undesirable heat effects are minimized and the resulting braze is of high quality.
    Keywords: MACHINE ELEMENTS AND PROCESSES
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  • 11
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    Impact testing on composite fan blades (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: SAMPE Quarterly; 5; July 197
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  • 12
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    Sealing of large leaks in high-vacuum systems subject to mechanical and thermal stresses (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The use of silicone rubber adhesive (particularly, G.E. RTV-108) for sealing large leaks in high vacuum systems subject to mechanical and thermal stresses is shown to be more effective than that of epoxy cements. The sealant is applied externally to the leak while the system is partially evacuated so that it is drawn into the hole.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Journal of Vacuum Science and Technology; 11; July-Aug
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  • 13
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    Aluminized alloy boosts turbine blade life (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Description of an aluminized alloy coating technique that involves first the application of a ductile, oxidation-resistant overlay, such as NiCrAl, which is then partially aluminized. The duplex protective system has performance advantages over conventional aluminide coatings in that it provides higher-temperature hot corrosion resistance over a longer service life.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Metal Progress; 106; Aug. 197
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  • 14
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    Friction and friction-generated temperature at a polymer-metal interface (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Results of friction and thermal tests of molded polyimide and pyrrone polymers are presented. The coefficient of sliding friction up to surface velocities of 2 m/sec and the coefficient of thermal expansion from 300 to 500 K were measured. An apparatus was constructed to measure simultaneously the coefficient of sliding friction and the friction-generated temperature. Measurements were made at a nominal pressure-velocity product of 0.25 MN/msec and at temperatures between 300 and 500 K.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Polymer Engineering and Science; 14; Apr. 197
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  • 15
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    Solid state and fusion resistance spot welding of TD-NiCr sheet (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Keywords: MACHINE ELEMENTS AND PROCESSES
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  • 16
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    Ultrasonic examination of welded joints of great thickness in mechanical equipment under pressure (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The requirements involved in choosing ultrasonic devices, the factors that affect testing, and recommended calibration methods are discussed. The ultrasonic testing method is the only method that up to now permits detection of defects in welded joints of great thickness. The results are conditioned by the performances of the devices employed as well as by the degree of instruction of the personnel.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: the 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 199-203
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  • 17
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    Influence of ultrasounds on electrolytic polishing (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: On the basis of study of the electrolytic polishing of metal pieces, the following conclusions can be drawn: (1) Utilization of ultrasonically irradiated electrolytes in the electrolytic polishing of copper and steel pieces leads to enhanced polishing quality. (2) Polishing time for the reference pieces was twice as long as for the test pieces. (3) The chemical attack exerted on the surface of the test pieces in order to get the structure of the respective metal lasted less than half as long and yielded superior qualitative results in the copper as well as in the OT 60-2 steel test pieces polished with ultrasonically irradiated electrolytes. (4) The utilization of higher polishing current densities can be explained by the fact that the cavitational effect that arises in the electrolyte owing to ultrasounds contributes to an increase in the solution's electrical conductivity and elimination of gases from the electrolyte.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: the 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 210-214
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  • 18
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    Monitoring the presence of foreign bodies in the equipment (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The methods for monitoring the presence of foreign bodies in radio electronic equipment are discussed. Descriptions of the structural design under the operating principle of the device for detecting foreign bodies weighing to 0.0026 grams are given.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 100-102
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  • 19
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    Process for manufacturing slit collimators (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Peculiarities are described of the manufacturing process and the control of elements of slit collimators, the structural design of the required equipment and the process or assembling the collimators.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 89-91
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  • 20
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    Method of applying a mirror reflecting layer to instrument parts (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: A method follows for applying a mirror reflecting layer to the surfaces of parts, instruments, apparatus, and so on. A brief analysis is presented of the existing methods of obtaining the mirror surface and the advantages of the new method of obtaining the mirror surface by polymer casting mold are indicated.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 84-88
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  • 21
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    Process of manufacturing small-module gears with internal coupling (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The small module geared coupling of an undulatory transmission is considered. Versions of the manufacture of gears with internal coupling and the instruments and equipment used, are reported.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 77-79
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  • 22
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    Process of manufacturing grids from wire less than 0.025 MM in diameter by the galvanic growth method (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The process of manufacturing grids, the peculiarities of the structural design, the fittings, the requirements on the tools and work area are discussed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 80-83
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  • 23
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    Prospective areas in the production technology of scientific equipment for space research (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The average labor of individual types of operations in the percentage ratio of the total labor consumption of manufacturing scientific instruments and apparatus for space research is presented. The prospective areas in the production technology of billet, machining, mechanical assembly, installation and assembly, adjustment and regulation and testing and control operations are noted. Basic recommendations are made with respect to further reduction of labor consumption and an increase in the productivity of labor when manufacturing scientific equipment for space research.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 69-76
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  • 24
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    Servosystem with an undulatory reducing gear (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The development of a potentiometric servosystem is described that has a dc microservomotor, which is the built in drive of an undulatory reducing gear. The operation of the system and the structural design of the undulatory reducing gear are elaborated. Results are presented from analyzing some tests of various types of undulatory reducing gear generators.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 44-53
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  • 25
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    Effectiveness of solid lubricant coatings for friction in hard vacuum (10-9 tor) (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A study was made of the efficiency of solid lubricating coatings, based on MoS2 with various binders, during friction and under highvacuum conditions. Mass spectrometry was used for an analysis of the composition of the gas evolved from the coatings in the friction process. It is shown that the vacuum level, loading, and sliding velocity influence coating effectiveness. In the friction process the solid lubricant coatings yield characteristic decay products associated with the chemical nature of the binders. The mechanism of coating breakdown during friction is associated with the binder breakdown mechanism.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 99-112
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  • 26
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    Influence of low temperatures of friction and wear (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A brief review of studies on low-temperature friction are briefly reviewed. A facility and technique for studying friction both in air and in vacuum at temperatures of +20 and -190 C is described. Results of a wear study of structural steels operating together with chromium steel are presented. It is shown that reduction of the test temperature in vacuum leads in certain cases to marked increase of the wear magnitude and friction coefficient. This is associated not only with the general change of the mechanical properties of the materials but also with the influence of temperature reduction on the hardening and structural formation taking place in the surface layers during friction.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 65-75
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  • 27
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    Study of the possibility of using solar radiant energy for welding and brazing metals (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The solar spectrum at the surface of the earth is analyzed. A facility for creating concentrated solar radiant energy flux is described, and data on its energetic capabilities are presented. The technology of solar welding by the fusion technique and joining by high-temperature brazing is examined. The use of concentrated solar radiant energy for welding and brazing metals and alloys is shown. The results of mechanical tests and microscopic and macroscopic studies are presented.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 9-18
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  • 28
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    Asperity lubrication and cavitation in face seals (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The basic aspect of parallel-surface lubrication that distinguishes it from other areas of lubrication technology is that classical lubrication theory does not predict the existence of a stable hydrodynamic film for steady-state, isothermal, incompressible flow between smooth, parallel surfaces. Hydrodynamic films between apparently parallel surfaces have been observed in practice and are often essential for the reliable performance of thrust bearings and seals. In order to account for this fortunate discrepancy between classical theory and experiment, load-support mechanisms relating to accidential features characteristic of seal performance, which relax one or more of the assumptions in the classical theory and permit the theoretical prediction of load support are proposed. Some of the features that have been analyzed are vibratory effects such as wobble and bounce, surface waviness, nonsymmetric rotation resulting from various types of misalignment, lubricant density change, non-Newtonian lubricant effects, and surface roughness.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NBS The Role of Cavitation in Mech. Failures; p 77-87
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  • 29
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    On particle motion in an electric welding arc treated with sonic or ultrasonic oscillations (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The criteria for the stability of the subharmonic, harmonic, or superharmonic oscillations determine the relation between acoustic field parameters and particle parameters. The derived formulas underlie the destruction of the fragile Widmanstatten structure in weldings and therefore the designing of the generators that must be used for this welding process.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 131-138
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  • 30
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    Cracking and reformation of saturated hydrocarbons by ultrasound in the presence of water (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The exposure of saturated hydrocarbons to ultrasound (800 kHz, 6 W/sq cm) in the presence of water results in: (1) cleavage of the carbon chain, producing saturated and unsaturated hydrocarbons with a lower number of carbons than the initial hydrocarbon (cracking); and (2) recombination after cleavage, producing saturated and unsaturated hydrocarbons with a higher number of carbons than the initial hydrocarbon (reformation). The addition of argon facilitates these phenomena. The effects are attributed to a homolytic (radical) mechanism occurring within the cavitation bubbles under the effects of microsparks.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 139-147
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  • 31
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    Contributions to the use of macrosounds for boiler decrusting (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The results of an investigation indicate the following: (1) The deposition of incrustations on the heating surfaces of steam boilers can be prevented by inserting between heating surface and water an insulating layer on which the boiler incrustation will be deposited. (2) The insulating layer reduces the coefficient of heat transmission by 2%. (3) The insulating layer can be removed by macrosounds with a frequency of about 20 kHz, after any interval of boiler operation.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 126-130
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  • 32
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    Contributions to study of the stability of the electric welding arc under the action of acoustic pressure (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: During the treatment of an electric welding arc with ultrasonic oscillations, an improvement was found in overall source-arc stability. Theoretical explanations are provided for this phenomenon and formulas of equivalence between the classical arc and the treated arc are derived, taking stability as their criterion. A knowledge of this phenomenon can be useful in extending the applications of ultrasounds to different forms of electric arcs.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 118-125
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  • 33
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    Acoustical levitation for space processing (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: It is pointed out that many space-manufacturing processes will require the manipulation of weightless molten material within a container in such a way that the material does not touch the container wall. A description is given of an acoustical method which can be used for the positioning and shaping of any molten material including nonconductors such as glasses. The new approach makes use of an acoustical standing wave which is excited within an enclosure or resonator.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Astronautics and Aeronautics; 12; July-Aug
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  • 34
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    Auger analysis of films formed on metals in sliding contact with halogenated polymers (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The use of Auger electron spectroscopy (AES) to search for transferred polymer must contend with the fact that there has been no published work on Auger analysis of polymers. Since this is a new area for AES, the Auger spectra of polymers and of halogenated polymers in particular is discussed. It is shown that the Auger spectra of halogenated polymers have certain characteristics that permit an assessment of whether a polymeric transfer film has been established by sliding contact. The discussion is general and the concepts should be useful in considering the Auger analysis of any polymer. The polymers chosen for this study are the halogenated polymers polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and polychlorotrifluorethylene (PCTFE).
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Journal of Applied Physics; 45; July 197
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  • 35
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    Research on wood bending in a macrosonic field (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Woodworking often requires the wood to be bent into different shapes. In view of the fact that macrosonic waves compress and expand the medium through which they are being propagated we assumed that wood subjected to the action of these waves during the bending process would have enhanced plasticity as a result of the loosening-up that takes place in it, as well as of the reduction in effort. To this effect, the bending of wood plasticized in a macrosonic field was studied. This bending took place under good conditions, and structural analyses conducted with the aid of an electron microscope proved initial premises to be corrent. Applied on an industrial scale, this procedure would contribute to improving the technology of wood bending as well as to eliminating factory spoilage.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 234-237
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  • 36
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    Some aspects of using ultrasounds to improve sulfurous mineral flotation technology (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The results are discussed which were obtained with a new method of desorption of collector reagents connected with improving the selectivity of the flotation of copper and lead concentrate through the action of ultrasounds. Analysis of the results obtained by treating copper and lead concentrate in an ultraacoustic field indicates an increase in the copper content of the copper concentrate, of the lead content in the lead concentrate and, at the same time, a reduction in the lead of the copper concentrate.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 112-117
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  • 37
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    On the dynamic stability of the focus of deformation in the cold drawing of tubes on an ultrasonically activated plug (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: In the case of macrosonic drawing, it was experimentally determined that tube eccentricity is less than in the case of tube drawing without macrosonics. On this basis, a theoretical analysis was carried out of the effect of macrosounds on tube eccentricity, an analysis that qualitatively confirms the experimental data.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-15663); p 102-111
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  • 38
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    Some research concerning the cold drawing of tubes on an ultrasonically activated plug (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The results are discussed of studies of the influence of macrosounds on a metal's friction and deformation conditions at the focus of deformation, on the mechanical characteristics of cold-drawn tubes, and on the dynamic stability of the focus of deformation. In the course of these studies, experimental equipment was developed and perfected. Under the proposed conditions the cold drawing of tubes on an ultrasonically activated plug turned out to be viable and efficient.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 89-96
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  • 39
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    Powder pressing in a macrosonic field (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An investigation was conducted to extend the technology of powder product manufacturing to new forms and sizes, to improve their quality as well as pressing efficiency and to reduce waste. In the course of metal and nonmetal powder briquette pressing, macrosounds were associated with the external static pressing force, which led to an increase in the relative height, density and physicomechanical characteristics of the briquettes. This method permits the extension of the range of products that can be manufactured from powders and the improvement of their quality.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 77-83
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  • 40
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    Metalworking with ultrasonic energy (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The application of ultrasonic radiation for metal working of steel is discussed. It is stated that the productivity of the ultrasonic working is affected by the hardness of the material to be worked, the oscillation amplitude, the abrasive temperature, and the grain size. The factors that contribute to an increase in the dislocation speed are analyzed. Experimental data are provided to substantiate the theoretical parameters.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 60-66
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  • 41
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    Contributions to the study of ultrasonic machining (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Problems in the industrial application of ultrasounds are discussed. Starting from the industrial characteristics of ultrasonic working, especially of hard and fragile materials that are difficult to work by means of conventional methods, the characteristics of the feed system, the circulation system of the abrasive suspension, and the ultra-acoustic unit of machines for ultrasonic working are described. Experiments on the behavior of different types of ultra-acoustic unit design and on the optimal operating conditions connected with the manner of execution, fixation, and excitation conditions are analyzed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 53-59
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  • 42
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    Effect of gravity on liquid phase sintering (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The unique conditions offered by the earth orbital environment in material processing involving both solid and liquid phases, such as liquid phase sintering, were studied. An experimental development program involving both test and theoretical work was initiated. Experimental work using material combinations selected such that maximum information about the effect of gravity can be derived has been conducted. Wetting of the solid phase by the liquid during sintering is an important phenomenon in liquid phase sintering, and gravity has influence on both capillary phenomenon and density segregation; hence, material combinations were selected such that these two effects can be suitably studies. The experimental work is meant to form the basis for similar comparative work done under low-g conditions. The part of the model dealing with the capillary phenomenon, as related to liquid phase sintering and the effect of gravity on it, suggest that gravity will have negligible effect on the Bond number and that the cohesive force is dependent on both the amount of liquid phase and the angle of contact.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 963-1001
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  • 43
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    Acoustic field positioning for containerless processing (1974)
    In:  Other Sources
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    Publication Date: 2019-01-25
    Description: The non-contact positioning of materials in a space processing chamber is accomplished using a new type of acoustic levitator. Liquid and solid materials are positioned using a single source of sound. Fine control of position may be obtained by motion of an acoustical reflector. Electrical power required is usually less than 100 watts. The system operates satisfactorily at high and low temperatures and is adaptable as an add-on feature to existing space experiments. Containerless melting and solidification can be performed and a freely suspended liquid can be shaped to the contour of the sound field. Experiments are described in which aluminum, glass and plastic materials are melted and solidified in the containerless state. The system has applications to containerless crystal growth, melting and related processes.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 647-677
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  • 44
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    Acoustical positioning chamber for space processing (1974)
    In:  Other Sources
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    Publication Date: 2019-01-25
    Description: By readily levitating, positioning, and manipulating materials placed in it, the acoustical resonator can serve a variety of space processing operations, such as drawing crystals, degassing, and stirring of melts, and casting.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 679-690
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  • 45
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    System design considerations for free-fall materials processing (1974)
    In:  Other Sources
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    Publication Date: 2019-01-25
    Description: The design constraints for orbiting materials processing systems are dominated by the limitations of the flight vehicle/crew and not by the processes themselves. Although weight, size and power consumption are all factors in the design of normal laboratory equipment, their importance is increased orders of magnitude when the equipment must be used in an orbital facility. As a result, equipment intended for space flight may have little resemblance to normal laboratory apparatus although the function to be performed may be identical. The same considerations influence the design of the experiment itself. The processing requirements must be carefully understood in terms of basic physical parameters rather than defined in terms of equipment operation. Preliminary experiments and analysis are much more vital to the design of a space experiment than they are on earth where iterative development is relatively easy. Examples of these various considerations are illustrated with examples from the M518 and MA-010 systems. While these are specific systems, the conclusions apply to the design of flight materials processing systems both present and future.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 595-601
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  • 46
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    Performance of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped flexibly mounted spiral-groove thrust bearing (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A test program was conducted to determine the performance characteristics of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped spiral-groove thrust bearing designed for the Brayton cycle rotating unit (BRU). Hydrostatic, hybrid (simultaneously hydrostatic and hydrodynamic), and hydrodynamic tests were conducted in argon gas at ambient pressure and temperature ranges representative of operation to the 10.5 kWe BRU power-generating level. Performance of the gas lubricated bearings is presented including hydrostatic gas flow rates, bearing clearances, bearing temperatures, and transient performance.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TM-X-2999 , E-7675
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  • 47
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    Effect of surface topography on structural growth of thick sputtered films (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Primarily thick sputtered S-Monel, silver, and 304 stainless steel coatings were deposited on mica, glass, and metal substrates with various surface finishes to investigate the structural growth of the coating by scanning electron microscopy. Compositional changes within the coating were analyzed by X-ray dispersion microscopy. Defects in the surface finish act as preferential nucleation sites and form isolated and complex nodules and various surface overgrowths in the coating. These nodules do not disappear after full annealing. Further, they have undesirable effects on mechanial properties; cracks are initiated at the nodules when the coating is stressed by mechanical forces. These effects are illustrated by micrographs. Nodular growth within a coating can be minimized or eliminated by reducing the surface roughness.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7577 , E-7655
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  • 48
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    Effect of frictional heating on brake materials (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: An exploratory study of the properties of aircraft brake materials was made to determine ways of improving friction and wear behavior while minimizing surface temperatures. It is found that frictional variation at high temperature involves material softening and metal transfer, formation of oxides, and surface melting. The choice of proper materials to combat these effects is discussed. Minimum surface temperatures are found to result from use of materials with large density-specific heat and density-specific heat-conductivity factors, use of a higher load-lower friction system, and maximization of the contact area. Some useful trade-off criteria for the size of brake disks against weight considerations are suggested. Additional information on material behavior and peak braking temperatures was gathered from an inspection of used brake pads and rotor disks.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Wear; 30; Oct. 197
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  • 49
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    Unpowered to powered failure rate ratio - A key reliability parameter (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: It is shown that the initial assumption of the ratio of unpowered to powered failure rates can have a strong influence on the design of a modular system intended for space missions. The analysis is performed for parallel systems and for triple modular redundant systems. Parallel systems are shown to be much more sensitive to the unpowered to powered failure rate ratio than the TMR/Spares systems, however, regardless of which standby redundancy technique is considered, the dependence of the system reliability on this ratio increases as the number of standby spares increases.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: IEEE Transactions on Reliability; R-23; Apr. 197
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  • 50
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    Experimental evaluation of stresses in spherically hollow balls (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An analysis was undertaken to evaluate stresses within spherically hollow ball bearings proportioned for 40, 50, and 60% mass reductions. Strain gage rosettes were used to determine principal strains and stresses in the steel ball models statically loaded in various orientations. Dimensionless results are reported for the balls under flate plate contact loads. Similitude considerations permit these results to be applied to calculate stresses in hollow ball bearings proportioned to these mass reductions.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-2445
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  • 51
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    Design and testing of a tandem row pump inducer (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The design and testing of a tandem row pump inducer having a supercavitating first stage with a 0.60 hub ratio is presented. The second stage tested was a helical impeller with a 0.70 hub ratio. A cubic arc transition was utilized to accomplish the hub change. The first stage had two blades and the free-vortex design approach was empirically modified based on previous experience. The recommended second stage design having four blades and using cambered blade section is presented but the model was not built or tested. The more simple helix was built instead to reduce cost. Data taken included head generation, cavitation observations and unsteady head fluctuations over the 0-100Hz range.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120374 , TR-7117-1
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  • 52
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    Analysis of an all-metallic resilient-pad gas-lubricated thrust bearing (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A resilient-pad gas thrust bearing that does not contain any elastomers in the bearing assembly is described and analyzed. The bearing consists of sector-shaped pads mounted asymmetrically on resilient foil beams. The effects of bearing design parameters on performance are shown. Performance of a resilient-pad bearing is compared with that of a pivoted-pad bearing.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7724 , E-7966
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  • 53
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    Comparison of experimental and predicted performance of 150-millimeter-bore solid and drilled ball bearings to 3 million DN (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Seven 150-millimeter-bore ball bearings were run under 8900-newton (2000-lbf) thrust load at speeds from 6670 to 20,000 rpm (1 million to 3 million DN). Four of the bearings had conventional solid balls, and three bearings had drilled (cylindrically hollow) balls with 50-percent mass reduction. The bearings were under-race cooled and slot lubricated with a type 2 ester oil at flow rates from 4.35 x 0.001 to 5.94 x 0.001 cubic meter/min (1.15 to 1.57 gal/min). Friction torque and temperature were measured on all bearings. While there was considerable spread in the temperature data, the drilled ball bearings tended to run slightly cooler than the solid ball bearings at higher speeds. No significant difference in torque was noted, however, between the solid and drilled ball bearings. One bearing of each type was rerun at 17,800-newton (4000-lbf) thrust load. The solid ball bearings performed satisfactorily at 3 million DN. However, at about 2 million DN the drilled ball bearing experienced a broken ball, and cracks appeared in other balls as a result of flexure fatigue. Metallurgical examination of the cracked balls indicated a brittle structure in the bore of the drilled balls.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7737 , E-7722
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  • 54
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    Combined effects of hydrazine exposure and endurance testing on solenoid-actuated valve performance (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Results are presented from a test program which was conducted to assess the capability of various solenoid-actuated valve design concepts to provide performance characteristics commensurate with long-duration (ten-year) missions to explore the outer planets. The valves were installed in a hydrazine flow test setup and periodically cycled during a nine-month test period under test conditions comparable to anticipated mission operating conditions. In situ valve performance was periodically determined, and leakage was continuously monitored.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-139360 , JPL-TM-33-691
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  • 55
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    Development of sputtered techniques for thrust chambers, task 1 (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Filler materials proposed for use in the sputter fabrication regeneratively cooled thrust chambers were evaluated. Low melting castable alloys, CERROBEND. CERROCAST, and CERROTRU, slurry applied SERMETEL 481 and flame-sprayed aluminum were investigated as filler materials. Sputter deposition from a cylindrical cathode inverted magnestron was used to apply an OFHC copper closeout layer to filled OFHC copper ribbed-wall cylindrical substrates. The sputtered closeout layer structure was evaluated with respect to filler material contamination, predeposition machining and finishing operations, and deposition parameters. The application of aluminum by flame-spraying resulted in excessiver filler porosity. Though the outgassing from this porosity was found to be detrimental to the closeout layer structure, bond strengths in excess of 10,500 psi were achieved. Removal of the aluminum from the grooves was readily accomplished by leaching in a 7.0 molar solution of sodium hydroxide at 353 K. Of the other filler materials evaluated, CERROTRU was found to be the most suitable material with respect to completely filling the ribbed-wall cylinders and vacuum system compatibility. However, bond contamination resulted in low closeout layer bond strength with the CERROTRU filler. CERROBEND, CERROCAST, and SERMETEL 481 were found to be unacceptable as filler materials.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-134629 , FR-6353-VOL-1
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  • 56
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    Holographic and ultrasonic detection of bond flaws in aluminum panels reinforced with boron-epoxy (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental investigation was made of the application of holographic interferometry to the nondestructive detection of unbonded areas (flaws) in bonded panels. Flaw detection results were compared with results obtained with an ultrasonic flaw detector. Holography, with panel deformation accomplished by a reduction in ambient pressure, is less sensitive for flaws beneath 5 and 10 plies of boron-epoxy than the ultrasonic method, though it does have its operational advantages. A process for the manufacture of bonded panels which incorporate known unbonded areas was also developed. The unbonded areas were formed without the use of foreign materials, which makes the method suitable for the construction of reference standards for bonded panels whenever needed for the proper setup of ultrasonic flaw-detection instruments.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7632 , L-9410
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  • 57
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    Design and fabrication of prototype system for early warning of impending bearing failure (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A test program was conducted with the objective of developing a method and equipment for on-line monitoring of installed ball bearings to detect deterioration or impending failure of the bearings. The program was directed at the spin-axis bearings of a control moment gyro. The bearings were tested at speeds of 6000 and 8000 rpm, thrust loads from 50 to 1000 pounds, with a wide range of lubrication conditions, with and without a simulated fatigue spall implanted in the inner race ball track. It was concluded that a bearing monitor system based on detection and analysis of modulations of a fault indicating bearing resonance frequency can provide a low threshold of sensitivity.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120294 , MTI-74TR34
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  • 58
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    Rolling-element fatigue life of silicon nitride balls (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The five-ball fatigue tester was used to evaluate silicon nitride as a rolling-element bearing material. Results indicate that hot-pressed silicon nitride running against steel may be expected to yield fatigue lives comparable to or greater than those of bearing quality steel running against steel at stress levels typical rolling-element bearing application. The fatigue life of hot-pressed silicon nitride is considerably greater than that of any ceramic or cermet tested. Computer analysis indicates that there is no improvement in the lives of 120-mm-bore angular--contact ball bearings of the same geometry operating at DN values from 2 to 4 million where hot-pressed silicon nitride balls are used in place of steel balls.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7794 , E-7219
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  • 59
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    Ferrographic analysis of wear debris from boundary lubrication experiments with a five-ring polyphenyl ether (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The types of wear particles generated by a five-ring polyphenyl ether in boundary lubrication experiments in various atmospheres were determined by ferrographic analysis. The types of wear particles observed included cylindrical or rocklike organometallic debris, adhesive and cutting wear particles, and some spherical debris. Interpretations as to the mechanism of generation of the various types of particles are presented.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7804 , E-8007
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  • 60
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    Optimization of self-acting herringbone-grooved journal bearings for maximum stability (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Groove parameters were determined to maximize the stability of herringbone-grooved journal bearings. Parameters optimized were groove depth, width, length, and angle. Optimization was performed by using a small-eccentricity, infinite-groove analysis in conjunction with a previously developed Newton-Raphson procedure for bearings with the smooth member rotating or with the grooved member rotating at low compressibility numbers, and a newly developed vector technique for bearings with the grooved member rotating at high compressibility numbers. The design curves in this report enable one to choose the optimum bearing for a wide range of operating conditions. Compared with bearings optimized to maximize load capacity, bearings optimized for stability allow a thousandfold increase in bearing-supported mass in some cases before onset of instability, and lose no more than 77 percent of their load capacity in any case studied. Stability is much greater when the grooved member rotates.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7803 , E-7793
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  • 61
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    Development of an improved membrane for a vapor diffusion water recovery process (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Recovery of potable water from urine on manned space missions of extended duration was the objective of work aimed at the improvement of membrane performance for the vapor diffusion process (VDR). Kynar, Teflon, PVC, and polysulfone candidate membranes were evaluated from chemical, thermal, mechanical, and fabricating standpoints to determine their suitability for operation in the VDR pervaporation module. Pervaporation rates and other performance characteristics were determined in a breadboard pervaporator test rig. Kynar and Teflon membranes were demonstrated to be chemically stable at pervaporation temperatures in urine pretreated with chromic acid bactericide. The separation of the pervaporator and condenser modules, the use of a recirculating sweep gas to conduct pervaporate to the condenser, and the selection of a hollow fiber membrane configuration for pervaporator module design is recommended as a result of the investigation.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-137544
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  • 62
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    The application of acoustic emission technique to fatigue crack measurement (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The applicability of acoustic emission technique to measure fatigue cracks in aluminum alloy specimens was investigated. There are several variables, such as the metallurgical and the physical treatment of the specimen, that can affect the level of acoustic activity of a fatigue specimen. It is therefore recommended that the acoustic emission technique be supplemented by other nondestructive evaluation methods to obtain quantitative data on crack growth.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7695 , L-9530
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  • 63
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    Experimental evaluation of stresses in cylindrically hollow (drilled) balls (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental stress analysis was undertaken to evaluate stresses within cylindrically hollow (drilled) bearing balls proportioned for 40, 50, and 60 percent mass reductions. Strain gage rosettes were used to determine principal strains and stresses in the steel ball models statically loaded in various orientations. Results are reported for 127 mm OD balls under 44,500 N loads. Similitude considerations permit these results to be applied to calculate stresses in actual size drilled bearing balls proportioned to these mass reductions.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-2439
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  • 64
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    Design, fabrication, assembly, and test of a liquid hydrogen acquisition subsystem (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The development of a cryogenic fluid system to supply liquid hydrogen to a turbopump at flowrates up to 7.5 pounds per second for a period of approximately 5 seconds before refill, is discussed. Refill is accomplished in less than 10 seconds, during which a constant flowrate can be maintained to the pumps. Diagrams are provided to show the configuration of the system. Subsystem acceptance and functional tests, including acquisition subsystem expulsion, pressurization, and refill were performed. The tests included: (1) thermodynamic vent system operation, (2) warm-gas pressurization effects, (3) hydraulic pressure surge effects, (4) screen device operational limitations, (5) feedline vapor control, and (6) two-phase refill.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120447 , MDC-G5360
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  • 65
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    Transient rotordynamic analysis for the space-shuttle main engine high-pressure oxygen turbopump (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A simulation study was conducted to examine the transient rotordynamics of the space shuttle main engine (SSME) high pressure oxygen turbopump (HPOTP) with the objective of identifying, anticipating, and avoiding rotordynamic problem areas. Simulations were performed for steady state operations at emergency power levels and for critical speed transitions. No problems are indicated in steady state operation of the HPOTP emergency power levels, although the results indicated that a rubbing condition will be experienced during critical speed transition at shutdown, particularly involving rotor deceleration rate and imbalance distribution rubbing at the turbine floating-ring seals. The condition is correctable by either reducing the imbalance at the HPOTP hot gas turbine wheels, or by a more rapid deceleration of the rotor through it critical speed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-140455
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  • 66
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    Friction behavior of 304 stainless steel of varying hardness lubricated with benzene and some benzyl structures (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The lubricating properties of some benzyl and benzene structures were determined by using 304 stainless steel surfaces strained to various hardness. Friction coefficients and wear track widths were measured with a Bowden-Leben type friction apparatus by using a pin-on-disk specimen configuration. Results obtained indicate that benzyl monosulfide, dibenzyl disulfide, and benzyl alcohol resulted in the lowest friction coefficients for 304 stainless steel, while benzyl ether provided the least surface protection and gave the highest friction. Strainhardening of the 304 stainless steel prior to sliding resulted in reduced friction in dry sliding. With benzyl monosulfide, dibenzyl disulfide, and benzyl alcohol changes in 304 stainless steel hardness had no effect upon friction behavior.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7787 , E-7909
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  • 67
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    Feasibility study for the manufacture of zero gravity pharmaceuticles, immunological, and viral agents (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The feasibility of extracting, isolating, purifying, separating, or preparing medical and biological products of high socio-economic value in space was studied. In particular, the study was designed to concentrate on the isolation or purification of virals, pharmaceutical and immunological agents by means of electrophoresis, as the Apollo 16 flight demonstrated that a mixed population of latex spheres (.2 and .8 microns) could be successfully separated by electrophoresis in space and without sedimentation with minimal convection. This prompted NASA scientists to look into the possibility of carrying out types of biochemical experiments that would utilize space for medical purposes.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120424
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  • 68
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    Feasibility study for the manufacture of zero gravity pharmaceuticals, immunological, and viral agents, appendices (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: For abstract, see N74-32929.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120425
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  • 69
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    Rocket having barium release system to create ion clouds in the upper atmosphere (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A chemical system for releasing a good yield of free barium atoms and barium ions to create ion clouds in the upper atmosphere and interplanetary space for the study of the geophysical properties of the medium is presented.
    Keywords: MACHINE ELEMENTS AND PROCESSES
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  • 70
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    Design, fabrication, and operation of a test rig for high-speed tapered-roller bearings (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A tapered-roller bearing test machine was designed, fabricated and successfully operated at speeds to 20,000 rpm. Infinitely variable radial loads to 26,690 N (6,000 lbs.) and thrust loads to 53,380 N (12,000 lbs.) can be applied to test bearings. The machine instrumentation proved to have the accuracy and reliability required for parametric bearing performance testing and has the capability of monitoring all programmed test parameters at continuous operation during life testing. This system automatically shuts down a test if any important test parameter deviates from the programmed conditions, or if a bearing failure occurs. A lubrication system was developed as an integral part of the machine, capable of lubricating test bearings by external jets and by means of passages feeding through the spindle and bearing rings into the critical internal bearing surfaces. In addition, provisions were made for controlled oil cooling of inner and outer rings to effect the type of bearing thermal management that is required when testing at high speeds.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-134595 , ITI-P-1248
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  • 71
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    Evaluation of chromium oxide and molybdenum disulfide coatings in self-acting stops of an air-lubricated Rayleigh step thrust bearing (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Two coatings for a Rayleigh step thrust bearing were tested when coasting down and stopping under self-acting operation in air. The thrust bearing had an outside diameter of 8.9 cm (3.5 in.), an inside diameter of 5.4 cm (2.1 in.), and nine sectors. The load was 73 N (16.4 lbf). The load pressure was 19.1 kN/per square meter (2.77 lbf/per square inch) on the total thrust bearing area. The chromium oxide coating was good to 150 stops without bearing deterioration, and the molybdenum disulfide coating was good for only four stops before bearing deterioration. The molybdenum disulfide coated bearing failed after nine stops.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7656 , E-7777
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  • 72
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    Effect of strain hardening on friction behavior of iron lubricated with benzyl structures (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Sliding friction experiments were conducted with iron, copper, and aluminum in contact with iron in various states of strain. The surfaces were examined in dry sliding and with various benzyl compounds applied as lubricants. Friction experiments were conducted with a hemispherical rider contacting a flat disk at loads of from 50 to 600 grams with a sliding speed of 0.15 cm/min. Results indicate that straining increases friction for dry sliding and for surfaces lubricated with certain benzyl structures such as dibenzyl disulfide. With other benzyl compounds (e.g., benzyl formate), friction coefficients are lower for strained than for annealed iron.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7661 , E-7842
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  • 73
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    Dynamic-scanning-electron-microscope study of friction and wear (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A friction and wear apparatus was built into a real time scanning electron microscope (SEM). The apparatus and SEM comprise a system which provides the capability of performing dynamic friction and wear experiments in situ. When the system is used in conjunction with dispersive X-ray analysis, a wide range of information on the wearing process can be obtained. The type of wear and variation with speed, load, and time can be investigated. The source, size, and distribution of wear particles can be determined and metallic transferal observed. Some typical results obtained with aluminum, copper, and iron specimens are given.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7700 , E-7913
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  • 74
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    Testing of improved polyimide actuator rod seals at high temperature and under vacuum conditions for use in advanced aircraft hydraulic systems (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Polyimide second-stage rod seals were evaluated to determine their suitability for applications in space station environments. The 6.35-cm (2.5-in.)K-section seal was verified for thermal cycling operation between room temperature and 478 K (400 F) and for operation in a 133 micron PA(0.000001 mm Hg) vacuum environment. The test seal completed the scheduled 96 thermal cycles and 1438 hr in vacuum with external rod seal leakage well within the maximum allowable of two drops per 25 actuation cycles. At program completion, the seals showed no signs of structural degradation. Posttest inspection showed the seals retained a snug fit against the shaft and housing walls, indicating additional wear life capability. Evaluation of a molecular flow section during vacuum testing, to inhibit fluid loss through vaporization, showed it to be beneficial with MIL-H-5606, a petroleum-base fluid, in comparison with MIL-H-83282, a synthetic hydrocarbon-base fluid.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-134601 , D6-41119
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  • 75
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    Theoretical study of production of unique glasses in space (1974)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: Analytical functional relationships describing homogeneous nucleation and crystallization in various supercooled liquids were developed. The time and temperature dependent relationships of nucleation and crystallization (intrinsic properties) are being used to relate glass forming tendency to extrinsic parameters such as cooling rate through computer simulation. Single oxide systems are being studied initially to aid in developing workable kinetic models and to indicate the primary materials parameters affecting glass formation. The theory and analytical expressions developed for simple systems is then extended to complex oxide systems. A thorough understanding of nucleation and crystallization kinetics of glass forming systems provides a priori knowledge of the ability of a given system to form a glass.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120417 , AR-1
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  • 76
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    Liquid-metal atomization for hot working preforms (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Rapid quenching of a liquid metal by atomization or splat cooling overcomes the major limitation of most solidification processes, namely, the segregation of alloying elements, impurities, and constituent phases. The cooling rates of different atomizing processes are related to the dendrite arm spacings and to the microstructure of the atomized powders. The increased solubility limits and the formation of metastable compounds in splat-cooled alloys are discussed. Consolidation of the powders by hot isostatic compaction, hot extrusion, or hot forging and rolling processes yields billets with properties equivalent to or better than those of the wrought alloys. The application of this powder processing technology to high-performance alloys is reviewed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Army Materials Technology Conference; Oct 22, 1972 - Oct 25, 1972; Portsmouth, NH
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  • 77
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    Two-dimensional Gaussian processes applied to the determination of contact between lubricated rolling surfaces (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Theoretical investigation of how effectively a lubricant film prevents metallic contact between two rolling surfaces (such as in ball bearings) as a function of surface roughness parameters. The parameters considered are the spectral moments of the two-dimensional surface obtained by superposition of the two rolling surfaces. We consider the peak height distribution, estimation of one-dimensional profile spectral moments, and the estimation of two-dimensional surface moments from several profile measurements are taken into account. Also given is an asymptotic relation between the mean film thickness and contact occurrences.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Annual Meeting of the American Statistical Association; Aug 26, 1974 - Aug 29, 1974; St. Louis, MO
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  • 78
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    Balancing of high speed interconnect shafting for operation above multiple bending critical speeds (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The present work first reviews the key elements of rotating system dynamics which are crucial to the control of lateral vibration levels for supercritical shafting of the type which is considered for use in advanced aircraft applications. Then the results of an analytical investigation of procedures for balancing flexible shafts designed for critical operation are discussed. Some of the conclusions made were: (1) even in undamped configuration, reasonably low vibration levels can be achieved through a sequential multiplane-multispeed balancing process; and (2) combination of analytical response and balancing prediction procedures yields a powerful tool for the dynamic analysis and design of advanced shaft-bearing systems.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: AHS PREPRINT 873 , Annual National V/STOL Forum; May 07, 1974 - May 09, 1974; Washington, DC
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  • 79
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    FOD impact testing of composite fan blades (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin, and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: National Symposium and Exhibition; Apr 23, 1974 - Apr 25, 1974; Buena Park, CA
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  • 80
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    Optimization of self-acting herringbone journal bearings for maximum stability (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Groove parameters were determined to maximize the stability of herringbone grooved journal bearings. Parameters optimized were groove depth, width, length, and angle. Optimization was performed using a small eccentricity, infinite groove analysis in conjunction with: (1) a previously developed Newton-Raphson procedure for bearings with the smooth member rotating or with the grooved member rotating at low compressibility numbers; (2) a newly-developed vector technique for bearings with the grooved member rotating at high compressibility numbers. The design curves in this report enable one to choose the optimum bearing for a wide range of operating conditions. These include: (1) compressibility numbers from 0 to 80; (2) length to diameter ratios from 1/4 to 2; and (3) smooth or grooved member rotating. Compared to bearings optimized to maximize load capacity, bearings optimized for stability allow a thousandfold increase in bearing-supported mass in some cases before onset of instability. Stability is much greater when the grooved member rotates.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: International Gas Bearing Symposium; Mar 26, 1974 - Mar 29, 1974; Southampton
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  • 81
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    Automation of the aircraft design process (1974)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The increasing use of the computer to automate the aerospace product development and engineering process is examined with emphasis on structural analysis and design. Examples of systems of computer programs in aerospace and other industries are reviewed and related to the characteristics of aircraft design in its conceptual, preliminary, and detailed phases. Problems with current procedures are identified, and potential improvements from optimum utilization of integrated disciplinary computer programs by a man/computer team are indicated.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: ICAS PAPER 74-24 , International Council of the Aeronautical Sciences Congress; Aug 25, 1974 - Aug 30, 1974; Haifa; Israel
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  • 82
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    Study of lubricant jet flow phenomena in spur gears (1974)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Lubricant jet flow impingement and penetration depth into a gear tooth space were measured at 4920 and 2560 rpm using a 8.89 cm (3.5 inch) pitch diameter 8 pitch spur gear at oil pressures from 70,000 to 410,000 n/sqm (10 psi to 60 psi). A high speed motion picture camera was used with xenon and high speed stroboscopic lights to slow down and stop the motion of the oil jet. An analytical model was developed for the vectorial impingement dept and for the impingement depth with tooth space windage effects included. The windage effects for oil drop size greater than .0076 cm (.003 inches). The analytical impingement dept compared favorably with experimental results above an oil jet pressure of 70,000 n/sqm (10psi). There was further penetration into the tooth space after impingement, but much of this oil was thrown out of the tooth space without further contacting the gear teeth.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TM-X-71572 , E-8012 , lubrication Conf.; Oct 08, 1974 - Oct 10, 1974; Montreal
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  • 83
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    Further development of chemical vapor deposition process for production of large diameter carbon-base monofilaments (1974)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The development of large diameter carbon-base monofilament in the 50 micron to 250 micron diameter range using the chemical vapor deposition process is described. The object of this program was to determine the critical process variables which control monofilament strength, monofilament modulus, and monofilament diameter. It was confirmed that wide scatter in the carbon substrate strength is primarily responsible for the scatter in the monofilament strength. It was also shown through etching experiments that defective substrate surface conditions which can induce low strength modular growth in the monofilament layers are best controlled by processing improvements during the synthesis of the substrate. Modulus was found to be linearily proportional to monofilament boron content. Filament modulus was increased to above 27.8MN/sq cm but only by a considerable increase in monofilament boron content to 60 wt. % or more. Monofilament diameter depended upon dwell time in the synthesis apparatus. A monofilament was prepared using these findings which had the combined properties of a mean U.T.S. of 398,000 N/sq cm, a modulus of 18.9 MN/sq cm (24,000,000 psi), and a diameter of 145 microns. Highest measured strength for this fiber was 451,000 N/sq cm (645,000 psi).
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-121267
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  • 84
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    Research study on materials processing in space experiment number M512 (1974)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: Conclusions of the team of specialists can be generalized as: (1) Brazing and welding of metal structures in an orbital near zero gravity condition are quite feasible. (2) Design of joints for fabrication in zero gravity will place less emphasis on the tolerances and proximity of the adjacent structures than on the quantity of liquid metal available. (3) Brazing of metallic joints has many advantages over electron beam welding for practical reasons: simplicity, launch weight, development costs, joint design tolerances, remotization, etc. (4) No evidence of different physical or mechanical properties of liquid metals in zero gravity was observed. However, many differences in liquid behavior were observed. Many of these effects have been called adhesion-cohesion phenomena.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120480
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  • 85
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    Characteristics of epitaxial garnets grown by CVD using single metal alloy sources (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Single metal alloys have been explored as the cation source in the chemical vapor deposition (CVD) of iron garnets. Growth of good quality single crystal garnet films containing as many as five different cations has been achieved over a wide range of deposition conditions. The relationship of film composition to alloy compositions and deposition conditions has been determined for several materials. By proper choice of the alloy composition and the deposition conditions, uncrazed deposits were grown on (111) gadolinium gallium garnet (GGG) substrates. Data on physical, magnetic and optical properties of representative films is presented and discussed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
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  • 86
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    Eutectic bonding of boron-aluminum structural components. II (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Eutectic bonding is a diffusion brazing process developed for fabricating boron-aluminum components from composite monolayer. This process relies on the diffusion of a thin surface film of copper into the aluminum matrix to form a liquid phase when heated above the copper-aluminum eutectic temperature of 1018 F. This type of fabrication offers design flexibility in that skin thickness may be varied, the stiffness geometry and orientation can be varied, and local reinforcement can be added. In addition, this type of boron-aluminum structure offers high efficiency. Also, this method of construction can be cost-comparative with complex titanium shapes; simple tooling permits easy layup, bonding is a one-step operation, and little finish machining is required.
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  • 87
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    Experimental evaluation of the exact point-speed and least-squares procedures for flexible rotor balancing by the influence coefficient method (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: ASME PAPER 73-DET-115
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  • 88
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    Organic fiber/epoxy pressure vessels (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: We evaluated the performance of an organic fiber in an epoxy matrix by winding 20-cm diam spherical and cylindrical pressure vessels of various designs. For the spherical vessels, we used soft aluminum liners 0.76 mm thick for a double boss design and 2 mm thick for a single boss design. For the cylindrical vessels, we used both 0.5-mm rubber liners and 0.76-mm soft aluminum liners. Vessels of both types were tested for burst pressure and cyclic fatigue at room temperature and liquid hydrogen temperature. The effects of temperature and vessel shape on the vessel performance factor were negligible. Our vessel fatigue data were marred by premature failure of the liners.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: SAMPE Quarterly; 5; Apr. 197
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  • 89
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    Selected reliability studies for the NERVA program (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An investigation was made into certain methods of reliability analysis that are particularly suitable for complex mechanisms or systems in which there are many interactions. The methods developed were intended to assist in the design of such mechanisms, especially for analysis of failure sensitivity to parameter variations and for estimating reliability where extensive and meaningful life testing is not feasible. The system is modeled by a network of interconnected nodes. Each node is a state or mode of operation, or is an input or output node, and the branches are interactions. The network, with its probabilistic and time-dependent paths is also analyzed for reliability and failure modes by a Monte Carlo, computerized simulation of system performance.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-139670
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  • 90
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    Design guide for helicopter transmission seals (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A detailed approach for the selection and design of seals for helicopter transmissions is presented. There are two major types of seals presently being used and they are lip type seals and mechanical type seals. Lip type seals can be divided in conventional lip seals and hydrodynamic lip seals. Conventional lip seals can be used for slow-speed, low-pressure, low-temperature sealing. Hydrodynamic lip seals although they are as pressure and temperature limited as conventional lip seals, can operate at a higher speed. Mechanical types seals are comprised of face seals and circumferential seals. Face seals are capable of high speed, high pressure, and high temperature. Circumferential seals can be used in high-speed and high-temperature applications, but will leak excessively at moderate pressures. The performance goals of transmission seals are a life that is at least equal to the scheduled overhaul interval of the gearbox component and a leakage rate of near zero.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120997 , SER-50791
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  • 91
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    Numerical evaluation of the surface deformation of elastic solids subjected to a hertzian contact stress (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The elastic deformation of two ellipsoidal solids in contact and subjected to Hertzian stress distribution was evaluated numerically as part of a general study of the elastic deformation of such solids in elastohydrodynamic contacts. In the analysis the contact zone was divided into equal rectangular areas, and it was assumed that a uniform pressure is applied over each rectangular area. The influence of the size of the rectangular area upon accuracy was also studied. The results indicate the distance from the center of the contact at which elastic deformation becomes insignificant.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7774 , E-7964
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  • 92
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    Pressure-viscosity measurements for several lubricants to 5.5 x 10 to the 8th power Newtons per square meter (8 x 10 to the 4th psi) and 149 C (300 F) (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A capillary viscometer was used to measure viscosity as a function of pressure, temperature, and shear stress for a number of lubricants. The conditions under which the measurements were made are specified. The results obtained for each material are analyzed. It was determined that all pressure-viscosity coefficients decreased with increasing temperature. Data from other techniques such as optical elastohydrodynamics, oscillating crystal, and low shear capillary viscometry were compared with the results obtained.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7736 , E-7952
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  • 93
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    Start-stop testing of two self-acting air-lubricated spiral groove thrust bearing coatings (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Start-stop tests were conducted on air-lubricated spiral-groove thrust bearings. Application of a matrix-bonded molybdenum disulfide (MoS2) coating over a porous chrome oxide coating resulted in significantly lower friction, compared to bearings coated with chrome oxide only. The MoS2 coated bearing sustained 15,000 start-stop cycles at a maximum of 3600 rpm. Each cycle was 15 seconds on, 30 seconds off. The chrome oxide coated bearing failed by local welding after 2030 cycles. Both types of coatings exhibited early failures under higher thrust loads when operating films were insufficient to sustain the load without overheating.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-134673 , FIRL-F-C3691
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  • 94
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    Electromagnetic containerless processing requirements and recommended facility concept and capabilities for space lab (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Containerless melting, reaction, and solidification experiments and processes which potentially can lead to new understanding of material science and production of new or improved materials in the weightless space environment are reviewed in terms of planning for spacelab. Most of the experiments and processes discussed are amenable to the employment of electromagnetic position control and electromagnetic induction or electron beam heating and melting. The spectrum of relevant properties of materials, which determine requirements for a space laboratory electromagnetic containerless processing facility are reviewed. Appropriate distributions and associated coil structures are analyzed and compared on the basis of efficiency, for providing the functions of position sensing, control, and induction heating. Several coil systems are found capable of providing these functions. Exchangeable modular coils in appropriate sizes are recommended to achieve the maximum power efficiencies, for a wide range of specimen sizes and resistivities, in order to conserve total facility power.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-120401
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 95
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    Testing and evaluation of solid lubricants for gas bearings (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The testing and results of testing solid film lubricants for gas lubricated bearing applications are reported. The tests simulated operational hazards of tilting pad gas bearings. The presence of a low coefficient of friction and the endurance of the solid film lubricant were the criteria for judging superior performance. All solid lubricants tested were applied to a plasma sprayed chrome oxide surface. Molybdenum disulfide and graphite fluoride were the solid lubricants tested; other test parameters included the method of application of the solid lubricant and the surface finish of the plasma sprayed coating. In general, the application of a solid film lubricant was found to significantly improve the coefficient of friction of the rubbing surfaces.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-2393 , MTI-73TR24
    Format: application/pdf
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  • 96
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    An assessment of separable fluid connector system parameters to perform a connector system design optimization study (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The key to optimization of design where there are a large number of variables, all of which may not be known precisely, lies in the mathematical tool of dynamic programming developed by Bellman. This methodology can lead to optimized solutions to the design of critical systems in a minimum amount of time, even when there are a great number of acceptable configurations to be considered. To demonstrate the usefulness of dynamic programming, an analytical method is developed for evaluating the relationship among existing numerous connector designs to find the optimum configuration. The data utilized in the study were generated from 900 flanges designed for six subsystems of the S-1B stage of the Saturn 1B space carrier vehicle.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TM-X-64849
    Format: application/pdf
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  • 97
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    Explosive-actuated valve design concept that eliminates blow-by (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A method of evaluating the normally open normally closed, explosive actuated valves that were selected for use in the trajectory correction propulsion subsystem of the Thermoelectric Outer Planet Spacecraft (TOPS) program is presented. The design philosophy which determined the requirements for highly reliable valves that could provide the performance capability during long duration (10 year) missions to the outer planets is discussed. The techniques that were used to fabricate the valves and manifold ten valves into an assembly with the capability of five propellant-flow initiation/isolation sequences are described. The test program, which was conducted to verify valve design requirements, is outlined and the more significant results are shown.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-138769 , JPL-TM-33-682
    Format: application/pdf
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  • 98
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    Ball motion and sliding friction in an arched outer-race ball bearing (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The motion of the ball and sliding friction in an arched outer-race ball bearing under thrust load is analyzed. Fatigue life evaluations were made. The analysis is applied to a 150-millimeter-bore ball bearing. The results indicated that for high-speed light-load applications the arched bearing has significant improvement in fatigue life over that of a conventional bearing. An arching of 0.254 mm (0.01 in.) was found to be optimal. Also, for an arched bearing a considerable amount of spinning occurs at the outer-race contacts.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7448 , E-7607
    Format: application/pdf
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  • 99
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    An investigation of chatter and tool wear when machining titanium (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The low thermal conductivity of titanium, together with the low contact area between chip and tool and the unusually high chip velocities, gives rise to high tool tip temperatures and accelerated tool wear. Machining speeds have to be considerably reduced to avoid these high temperatures with a consequential loss of productivity. Restoring this lost productivity involves increasing other machining variables, such as feed and depth-of-cut, and can lead to another machining problem commonly known as chatter. This work is to acquaint users with these problems, to examine the variables that may be encountered when machining a material like titanium, and to advise the machine tool user on how to maximize the output from the machines and tooling available to him. Recommendations are made on ways of improving tolerances, reducing machine tool instability or chatter, and improving productivity. New tool materials, tool coatings, and coolants are reviewed and their relevance examined when machining titanium.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TM-X-64830
    Format: application/pdf
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  • 100
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    Analysis of the dynamics of a nutating body (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The equations for the displacement, velocity, and acceleration of a point in a nutating body are developed. These are used to derive equations for the inertial moment developed by a nutating body of arbitrary shape. Calculations made for a previously designed nutating plate transmission indicate that that device is severely speed limited because of the very high magnitude inertial moment.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7569 , E-7696
    Format: application/pdf
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