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  • Physics  (5,087)
  • Fluid Mechanics and Thermodynamics
  • 2020-2020
  • 1975-1979  (2,551)
  • 1970-1974  (2,551)
  • 1945-1949  (44)
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  • 1
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    Heat Pipes for Alaskan Oil (1976)
    In:  CASI
    Details
    Publication Date: 2018-06-09
    Description: McDonnel Douglas Corporation is using a heat-pipe device, developed through the space program, to transport oil from Alaska's rich North Slope fields. It is being used to keep the ground frozen along the 798- mile pipeline saving hundreds of millions of dollars and protecting the tundra environment. Heatpipes are totally automatic, they sense and respond to climatic conditions with no moving parts, require no external power, and never need adjustment or servicing.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: Spinoff 1976; 74-75
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  • 2
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    Heat Pipe Design Handbook: Volume I (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: No abstract available
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NASA-CR-163661
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  • 3
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    Heat Pipe Design Handbook: Volume II (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This volume consists of a discussion of Fluid Properties (Chapter 1) and a description of the available Heat Pipe Computer Codes (Chapter 2). Appendix A contains appropriate International Scientific Units (SI) and Conversion Factors. The Users Manual for the Heat Pipe Fluid Properties Program (HPF) which is used to generate the fluid property data is presented in Appendix B. Tabulated fluid property data are listed in Appendix C.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NASA-CR-163662
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  • 4
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    A Simplified Theory of Porous Wall Cooling (1947)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: The rate of heat transfer between a fluid stream in turbulent flow and a smooth, solid wall is largely controlled by the relatively high resistance of the laminar sublayer next to the wall. Although this laminar layer ii extremely thin, heat can be transferred through it only by molecular diffusion. Hence the resistance of this layer is very much greater than for a layer the same thickness farther out in the stream where turbulent exchange is the controlling factor. The thickness of the laminar layer is difficult to define precisely, since there is a gradual transition to the turbulent flow outside, but for the usual scale of many engineering applications almost half the temperature difference between the fluid and the wall occurs in a layer of a few thousands of an inch in thickness. When the wall is made of porous material and a coolant gas is forced through the wall into the stream, it has been found that a very small flow rate of the coolant is remarkably effective in keeping the wall at a low temperature. The coolant flow rate required is such as to give an average velocity normal cooling wall of the order of 1 per cent of the main stream velocity. This flow rate is so low that clearly the injected gas must act as an insulator rather than as a normal coolant. Because of its relatively low velocity, the injected gas can have very little influence on heat convection or momentum transfer in the turbulent stream, and its effect must be confined to the laminar sublayer. The possible influence of the coolant flow on the thickness of the laminar layer will be discussed in Section V.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: JPL-PR-4-50
    Format: text
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  • 5
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    Two-Dimensional Motion of a Gas at Large Supersonic Velocities (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A large number of papers have been devoted to the problem of integration of equations of two-dimensional steady nonvertical adiabatic motion of a gas. Most of these papers are based on the application of the hodograph method of S. A. Chaplygin in which the plane of the hodograph of the velocity is taken as the region of variation of the independent variables in the equations of motion; the equations become linear in this plane. The exact integration of these equations is, however, obtained in the form of infinite series containing hypergeometric functions. The obtaining of such solutions and their investigation involves extensive computations. As a result, methods have been developed for the approximate integration of the equations of motion first transformed to a linear form. S. A. Chaplygin first pointed out such an approximate method applicable to flows in which the Mach number does not exceed 0.4.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1239 , Prikladnaia Matematika I Mekhanika, Tom XI
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  • 6
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    A Class of De Laval Nozzles (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A study is made herein of the irrotational adiabatic motion of a gas in the transition from subsonic to supersonic velocities. A shape of the de Laval nozzle is given, which transforms a homogeneous plane-parallel flow at large subsonic velocity into a supersonic flow without any shockwaves beyond the transition line from the subsonic to the supersonic regions of flow. The method of solution is based on integration near the transition line of the gas equations of motion in the form investigated by S. A. Christianovich.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1236 , Prikladnaia Matematika I Mekhanika, Tom XI
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  • 7
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    The Characteristics Method Applied to Stationary Two-Dimensional and Rotationally Symmetrical Gas Flows (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: By means of characteristics theory, formulas for the numerical treatment of stationary compressible supersonic flows for the two-dimensional and rotationally symmetrical cases have been obtained from their differential equations.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1211 , ZWB Forschungsbericht; Rept-1581
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  • 8
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    The Turbulent Flow in Diffusers of Small Divergence Angle (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The turbulent flow in a conical diffuser represents the type of turbulent boundary layer with positive longitudinal pressure gradient. In contrast to the boundary layer problem, however, it is not necessary that the pressure distribution along the limits of the boundary layer(along the axis of the diffuser) be given, since this distribution can be obtained from the computation. This circumstance, together with the greater simplicity of the problem as a whole, provides a useful basis for the study of the extension of the results of semiempirical theories to the case of motion with a positive pressure gradient. In the first part of the paper,formulas are derived for the computation of the velocity and.pressure distributions in the turbulent flow along, and at right angles to, the axis of a diffuser of small cone angle. The problem is solved.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1137 , Central Aero-Hydrodynaical Institute Reports; Rept-462
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  • 9
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    Vibration Survey of Blades in 19XB Axial-Flow Compressor (1948)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Strain gages were used to measure blade vibrations possibly causing failure in the 10-stage compressor of the 19XB jet-propulsion engine. The seventh and tenth stages were of great concern as a result of failures experienced by the manufacturer. Strain-gage records were obtained from all stages during acceleration, deceleration, and constant speed runs. Curves are presented herein showing the maximum allowable vibratory stress for a given speed, the change of the damping coefficient with the mounting of a strain gage at the base of the blade, the effect of rotor speed, on blade natural frequency, and the effect of the order of first bending-mode vibration on stress. It was found that for all stages the lower the order of vibration the higher the stress but no destructive vibrations were detected.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SE8A28
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  • 10
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    Effect of Air-Flow Distribution and Total-Pressure Loss on Performance of One-Sixth Segment of Turbojet Combuster (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: An investigation has been conducted on a one-sixth segment of an annular turbojet combustor to determine the effects of modification in air-flow distribution and total-pressure loss on the performance of the segment. The performance features investigated during this series of determinations were the altitude operational limits and the temperature-rise efficiency. Altitude operational limits of the combustor segment, for the 19XB engine using the original combustor-basket design were approximately 38,000 feet at 17,000 rpm and 26,000 feet at 10,000 rpm. The altitude operational limits were approximately 50,000 feet at 17,000 rpm and 38,000 feet at 10,000 rpm for a combustor-basket design in which the air-passage area in the basket was redistributed so as to admit gradually no more than 20 percent of the air along the first half of the basket. In this case the total pressure loss through the combustor segment was not appreciably changed from the total-pressure loss for the original combustor basket design. Altitude operational limits of the combustor segment for the 19XB engine were above 52,000 feet at 17,000 rpm and were approximately 23,000 feet at 10,000 rpm for a combustor-basket design in which the distribution of the air-passage area in the basket was that of the original design but where the total-pressure loss was increased to 19 times the inlet reference kinetic pressure at an inlet-to-outlet density ratio of 2.4. The total-pressure loss for the original design was 14 times the inlet kinetic reference pressure at an inlet-to-outlet density ratio of 2.4.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SE7K16
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  • 11
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    Heat Transfer from High-Temperature Surfaces to Fluids III - Correlation of Heat-Transfer Data for Air Flowing in Silicon Carbide Tube with Rounded Entrance, Inside Diameter of 3/4 Inch, and Effective Length of 12 Inches (1949)
    In:  CASI
    Details
    Publication Date: 2019-08-13
    Description: A heat-transfer investigation was conducted with air flowing through an electrically heated silicon carbide tube with a rounded entrance, an inside diameter of 3/4 inch, and effective heat-transfer length of 12 inches over a range of Reynolds numbers up to 300,000 and a range of average inside-tube-wall temperatures up to 2500 R. The highest corresponding local outside-tube-wall temperature was 3010 R.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA/RM-E9D12
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  • 12
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    Behavior of the Laminar Boundary Layer for Periodically Oscillating Pressure Variation (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The calculation of the phenomena within the boundary layer of bodies immersed in a flow underwent a decisive development on the basis of L. Prandtl's trains of thought, stated more than forth years ago, and by numerous later treatises again and again touching upon them. The requirements of the steadily improving aerodynamics of airplanes have greatly increased with the passing of time and recently research became particularly interested in such phenomena in the boundary layer as are caused by small external disturbances. Experimental results suggest that, for instance, slight fluctuations in the free stream velocities as they occur in wind tunnels or slight wavelike deviations of outer wing contours from the prescribed smooth course as they originate due to construction inaccuracies may exert strong effects on the extent of the laminar boundary layer on the body and thus on the drag. The development of turbulence in the last part of the laminar portion of the boundary layer is, therefore, the main problem, the solution of which explains the behavior of the transition point of the boundary layer. A number of reports in literature deal with this problem,for instance, those of Tollmien, Schlichting, Dryden, and Pretsch. The following discussion of the behavior of the laminar boundary layer for periodically oscillating pressure variation also purports to make a contribution to that subject.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1228 , Ludwig Prandtl zum 70. Geburtstage, Schriften der Deutschen Akademie der Luftfahrtforschung, Publications of the Germany academy for Aviation Research; 247-255
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  • 13
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    Some Aerodynamic Relations for an Airfoil in Oblique Flow (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Some aerodynamic relations are derived which exist between two infinitely long airfoils if one is in a straight flow and the other in oblique flow, and both present the same profile in the direction of flow.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1158 , Deutsche Luftfahrtforschung, Forschungsbericht; Rept-1497
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  • 14
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    Laboratory Report on the Investigation of the Flow around Two Turbine-Blade Profiles using the Interferometer Method (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: At the request of the Junkers Aircraft and Engine Construction Company, Engine Division, Dessau Main Plant, an investigation was made using the interferometer method on the two turbine-blade profiles submitted. The interferometer method enables making visible the differences in density and consequently the boundary layers that develop when a flow is directed on the profile. Recognition of the points on the profile at which separation of flow occurs is thus possible. By means of the interference photographs the extent of the dead-water region may be ascertained. The size of the dead-water region provides evidence as to the quality of the flow and allows a qualitative estimate of the amount of the flow losses. Interference photographs thus provide means of judging the utility of profiles under specific operating conditions and provide suggestions for possible changes of profile contours that might help to improve flow relations. Conclusions may be drawn concerning the influence of the blade-spacing ratio, the inlet-air angle, and the connection between the curvature of the profile contour and the point of separation of the flow from the profile surface.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1171 , Deutsche Luftfahrtforschung, Untersuchungen und Mitteilungen; Rept-2096
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  • 15
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    Experimental and Theoretical Investigations of Cavitation in Water (1945)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The cavitation in nozzles on airfoils of various shape and on a sphere are experimentally investigated. The limits of cavitation and the extension of the zone of the bubbles in different stages of cavitation are photographically established. The pressure in the bubble area is constant and very low, jumping to high values at the end of the area. The analogy with the gas compression shock is adduced and discussed. The collapse of the bubbles under compression shock produces very high pressures internally, which must be contributory factors to corrosion. The pressure required for purely mechanical corrosion is also discussed.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1078 , Eidgenoessische Technische Hochschule
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  • 16
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    Rotationally Symmetric Potential Flows (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: This paper includes the following topics: 1) Characteristic differential equations; 2) Treatment of practical examples; 3) First example: Diffuser; and 4) Second Example: Nozzle.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1244 , Chapter 4, Technische Hoschschule Dresden, Archives No. 44; Rept-44/4
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  • 17
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    Compressible Flow Tables for Air (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: This paper contains a tabulation of functions of the Mach number which are frequently used in high-speed aerodynamics. The tables extend from M = 0 to M = 10.0 in increments of 0.01 and are based on the assumption that air is a perfect gas having a specific heat ratio of 1.400.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L7K26
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  • 18
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    Fluid valve with wide temperature range (1976)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: A fluid valve suitable for either metering or pressure regulating fluids at various temperatures is provided for a fuel system as may be utilized in an aircraft gas turbine engine. The valve includes a ceramic or carbon pad which cooperates with a window in a valve plate to provide a variable area orifice which remains operational during large and sometimes rapid variations in temperature incurred from the use of different fuels.
    Keywords: Fluid Mechanics and Thermodynamics
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  • 19
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    NACA Conference on Turbojet-Engine Thrust Augmentation Research: A Compilation of the Papers Presented by NACA Staff Members (1948)
    In:  CASI
    Details
    Publication Date: 2019-08-14
    Description: The conference on Turbojet-Engine Thrust-Augmentation Research was organized by the NACA to present in summarized form the results of the latest experimental and analytical investigations conducted at the Lewis Flight Propulsion Laboratory on methods of augmenting the thrust of turbojet engines. The technical discussions are reproduced herewith in the same form in which they were presented. The original presentation in this record are considered as complementary to, rather than substitutes for, the committee's system of complete and formal reports.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA Conference on Turbojet-Engine Thrust - Augmentation Research; Oct 28, 1948; Cleveland, OH; United States
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  • 20
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    Variable Conductance Heat Pipe Technology (1974)
    In:  CASI
    Details
    Publication Date: 2019-08-14
    Description: A research and development program in variable conductance heat pipe technology is reported. The project involved: (1) theoretical and/or experimental studies in hydrostatics, (2) hydrodynamics, (3) heat transfer into and out of the pipe, (4) fluid selection, and (5) materials compatibility. The development, fabrication, and test of the space hardware resulted in a successful flight of the heat pipe experiment on the OAO-3 satellite. A summary of the program is provided and a guide to the location of publications on the project is included.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NASA-CR-114750 , TRW-13111-6060-RU-00
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  • 21
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    Analysis of Free-Flight Laminar, Transitional, and Turbulent Heat-Transfer Results at Free-Stream Mach Numbers Near 20 (Reentry F) (1971)
    In:  CASI
    Details
    Publication Date: 2019-08-14
    Description: Laminar, transitional, and turbulent heat-transfer data were measured during a reentry flight at a Mach number of 20 on a 5 deg half-angle cone 3.962 m (13 ft) long with an initial nose tip radius of 0.254 cm (0.1 in.). The free-stream Reynolds number increased during the prime data period from 7.0 x 10(exp 6) to 51.5 x 10(exp 6) per meter (2.1 x 10(exp 6) to 15.7 x 10(exp 6) per foot) and the ratio of wall to total temperature varied from 0.053 to 0.12. The angle of attack was less than 1deg for the prime data period. The experimental laminar and turbulent heating rates are compared with results from existing flat-plate prediction methods. At conditions of minimal tip blunting and angle of attack (above 26.8 km (88 000 ft)), values from a flat-plate laminar method agreed within 20 percent with the laminar data. The Schultz-Grunow skin-friction equation with reference enthalpy; conditions, with the Reynolds number based on distance from the transition location, and with the Colburn Reynolds analogy agreed within 10 percent with the experimental turbuleiit heating data. The Van Driest n skin-friction equation with Reynolds number greater than 10(exp 7) based on distance from the peak heating point and the Colburn Reynolds analogy was also within approximately 10 percent of the experimental turbulent heating data. A data correlation jbf the extent of transition and a simple empirical transition-zone heating correlation were also presented.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NASA-TM-X-2335 , L-7803
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  • 22
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    Thermal Analysis Methods and Basic Heat-Transfer Data for a Turbulent Heating Flight Experiment at Mach 20 (Reentry F) (1971)
    In:  CASI
    Details
    Publication Date: 2019-08-14
    Description: A heat-transfer experiment was flight conducted on a 5 deg half-angle cone, 396.2 cm (13 ft) in length, as it entered the sensible atmosphere under laminar, transitional, and turbulent boundary-layer conditions at a free-stream Mach number of about 20. Accurate turbulent-heat-transfer data with natural transition were obtained for correlation with theories in regions of simultaneous high Mach number, Reynolds number, enthalpy, and total-to-wall temperature ratio. Temperatures were measured at four depths through the 15.24-mm-thick (0.600-in.) beryllium wall. Experimental heating rates at 20 stations on the cone were determined independently from the outermost temperature measurement and from the temperature measurement at the second depth by a single-thermocouple inverse method and also from the temperature histories at all four depths by an integral method. The thermal data analysis procedure, associated problems, and results are presented herein.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NASA-TM-X-2282 , L-7520
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  • 23
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    Analytical Treatment of Normal Condensation Shock (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The condensation of water vapor in an air consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1174 , Heeres-Versuchsstelle; 66/72
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  • 24
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    Report on Investigation of Developed Turbulence (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The recent experiments by Jakob and Erk, on the resistance of flowing water in smooth pipes, which are in good agreement with earlier measurements by Stenton and Pannell, have caused me to change my opinion that the empirical Blasius law (resistance proportional to the 7/4 power of the mean velocity) was applicable up to arbitrarily high Reynolds numbers. According to the new tests the exponent approaches 2 with increasing Reynolds number, where it remains an open question whether or not a specific finite limiting value of the resistance factor lambda is obtained at R = infinity. With the collapse of Blasius' law the requirements which produced the relation that the velocity in the proximity of the wall varied in proportion to the 7th root of the wall distance must also become void. However, it is found that the fundamental assumption that led to this relationship can be generalized so as to furnish a velocity distribution for any empirical resistance law. These fundamental assumptions can be so expressed that for the law of velocity distribution in proximity of the wall as well as for that of friction at the wall, a form can be found in which the pipe diameter no longer occurs, or in other words, that the processes in proximity of a wall are not dependent upon the distance of the opposite wall.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1231 , Zeitschrift fuer Angewandte Matematik und Mechanik; 5; 2; 136-139
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  • 25
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    Lift Force of an Arrow-Shaped Wing (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The flow about a conical body of an ideal compressible fluid is considered. Assume that the velocity of the oncoming flow at infinity W is directed along the z-axis. The system of Cartesian coordinates x, y, z with origin at the vertex of the cone O is shown. From the considerations,of the dimensional theory, it may be found that along any ray issuing from O the components of the velocity u, v, W+w along the coordinate axes will maintain a constant value. It is further assumed that the conical body has such shape and disposition relative to the flow that u, v, and w are small in comparison with W.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1245 , Prikladnaya Matematika I Mekhanika; X; 513-520
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  • 26
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    Gas Motion in a Local Supersonic Region and Conditions of Potential-Flow Breakdown (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: For a certain Mach number of the oncoming flow, the local velocity first reaches the value of the local velocity of sound (M = 1) at some point on the surface of the body located within the flow. This Mach number is designated the critical Mach number M(sub cr). By increasing the flow velocity, a supersonic local region is formed bounded by the body contour and the line of transition from subsonic to supersonic velocity. As is shown by observations with the Toepler apparatus, at a certain flow Mach number M 〉 M(sub cr) a shock wave is formed near the body that closes the local supersonic region from behind. The formation of the shock wave is associated with the appearance of an additional resistance defined as the wave drag. In this paper, certain features are described of the flow in the local supersonic region, which is bounded by the contour of the body and the transition line, and conditions are sought for which the potential flow with the local supersonic region becomes impossible and a shock wave occurs. In the first part of the paper, the general properties of the potential flow in the local supersonic region, bounded by the contour of the profile and the transition line, are established. It is found that at the transition line, if it is not a line of discontinuity, the law of monotonic variation of the angle of inclination of the velocity vector holds (monotonic law). An approximation is given for the change in velocity at the contour of the body. The flow about a contour having a straight part is studied. In the second part of the paper, an approximation is given of the magnitudes of the accelerations at the interior points of the supersonic region. With the aid of these approximations, it is shown that for profiles convex to the flow the breakdown of the potential flow,associated with an increase of the Mach number of the oncoming flow, cannot be due to the formation of an envelope of the characteristics within the supersonic region. On the basis of the monotonic law, the transitional Mach number M is found, beyond which the potential flow with local supersonic region becomes impossible.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1213 , Prikladnaya Matematika i Mekhanika; 10; 4; 481-502
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  • 27
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    On the Theory of the Laval Nozzle (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In the present paper, the motion of a gas in a plane-parallel Laval nozzle in the neighborhood of the transition from subsonic to supersonic velocities is studied. In a recently published paper, F. I. Frankl, applying the holograph method of Chaplygin, undertook a detailed investigation of the character of the flow near the line of transition from subsonic to supersonic velocities. From the results of Tricomi's investigation on the theory of differential equations of the mixed elliptic-hyperbolic type, Frankl introduced as one of the independent variables in place of the modulus of the velocity, a certain specially chosen function of this modulus. He thereby succeeded in explaining the character of the flow at the point of intersection of the transition line and the axis of symmetry (center of the nozzle) and in studying the behavior of the stream function in the neighborhood of this point by separating out the principal term having, together with its derivatives, the maximum value as compared with the corresponding corrections. This principal term is represented in Frankl's paper in the form of a linear combination of two hypergeometric functions. In order to find this linear combination, it is necessary to solve a number of boundary problems, which results in a complex analysis. In the investigation of the flow with which this paper is concerned, a second method is applied. This method is based on the transformation of the equations of motion to a form that may be called canonical for the system of differential equations of the mixed elliptic-hyperbolic type to which the system of equations of the motion of an ideal compressible fluid refers. By studying the behavior of the integrals of this system in the neighborhood of the parabolic line, the principal term of the solution is easily separated out in the form of a polynomial of the third degree. As a result, the computation of the transitional part of the nozzle is considerably simplified.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1212 , Prikladnaya Matematika I Mekhanika; 10; 4; 503-512
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    On the Problems of Chaplygin for Mixed Sub-and Supersonic Flows (1947)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: There are investigated the problems of the flow of a supersonic jet out of a vessel with plane side walls and the problem of the supersonic flow about a wedge when there is a zone of local subsonic velocities ahead of the wedge.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1155 , Bulletin de L'Academie des Sciences de L'URSS; 9; 121-143
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  • 29
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    Equations for Adiabatic but Rotational Steady Gas Flows without Friction (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: This paper makes the following assumptions: 1) The flowing gases are assumed to have uniform energy distribution. ("Isoenergetic gas flows," that is valid with the same constants for the the energy equation entire flow.) This is correct, for example, for gas flows issuing from a region of constant pressure, density, temperature, end velocity. This property is not destroyed by compression shocks because of the universal validity of the energy law. 2) The gas behaves adiabatically, not during the compression shock itself but both before and after the shock. However, the adiabatic equation (p/rho(sup kappa) = C) is not valid for the entire gas flow with the same constant C but rather with an appropriate individual constant for each portion of the gas. For steady flows, this means that the constant C of the adiabatic equation is a function of the stream function. Consequently, a gas that has been flowing "isentropically",that is, with the same constant C of the adiabatic equation throughout (for example, in origination from a region of constant density, temperature, and velocity) no longer remains isentropic after a compression shock if the compression shock is not extremely simple (wedge shaped in a two-dimensional flow or cone shaped in a rotationally symmetrical flow). The solution of nonisentropic flows is therefore an urgent necessity.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1187 , Rept-44/1
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  • 30
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    Contribution to the Problem of Flow at High Speed (1949)
    In:  CASI
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    Publication Date: 2019-07-11
    Description: The authors regret that due to the lack of time the investigations could not be carried out to a more finished form. Especially in the first part it was intended to include a few further applications and to use them in the general considerations of this part. In spite of the fact that the intentions of the authors could not be realized, the authors felt that it would serve the aims of the competition to present part I in its present fragmentary form. The topics include: 1) A Few General Remarks Covering the Prandtl-Busemann Method; and 2) Effect of Compressibility in Axially Symmetrical Flow around an Ellipsoid.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1233 , Lilienthal-Gesellschaft fuer Luftfahrtforschung Bericht S 13/1, Part 1; 40-68; Rept-13/1
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  • 31
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    Heat Transmission in the Boundary Layer (1949)
    In:  CASI
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    Publication Date: 2019-07-11
    Description: In the present paper which deals with the heat transfer between the gas and the wall for large temperature drops and large velocities use is made of the method of Dorodnitsyn of the introduction of a new independent variable, with this difference, however, that the relation between the temperature field (that is, density) and the velocity field in the general case considered is not assumed given but is determined from the solution of the problem. The effect of the compressibility arising from the heat transfer is thus taken into account (at the same time as the effect of the compressibility at the large velocities). A method is given for determining the coefficients of heat transfer and the friction coefficients required in many technical problems for a curved wall in a gas flow at large Mach numbers and temperature drops. The method proposed is applicable both for Prandtl number P = 1 and for P not equal to 1.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1229 , Prikladnaya Matematika I Mekhanika, Tom X; 449-474
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  • 32
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    Theoretical Analysis of Stationary Potential Flows and Boundary Layers at High Speed (1948)
    In:  CASI
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    Publication Date: 2019-07-11
    Description: The present report consists of two parts. The first part deals with the two-dimensional stationary flow in the presence of local supersonic zones. A numerical method of integration of the equation of gas dynamics is developed. Proceeding from solutions at great distance from the body the flow pattern is calculated step by step. Accordingly the related body form is obtained at the end of the calculation. The second part treats the relationship between the displacement thickness of laminar and turbulent boundary layers and the pressure distribution at high speeds. The stability of the boundary layer is investigated, resulting in basic differences in the behavior of subsonic and supersonic flows. Lastly, the decisive importance of the boundary layer for the pressure distribution, particularly for thin profiles, is demonstrated.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1189 , Lilienthal-Gesellschaft fuer Luftfahrtforschung Bericht S13/1 Teil; 7-24
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  • 33
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    Flow Measurement by Means of Light Interference (1949)
    In:  CASI
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    Publication Date: 2019-07-11
    Description: There has been under development for the high-speed wind tunnel of the LFA an optical measuring arrangement for the qualitative and quantitative investigation of flow. By the use of interference measurements, the determination of density at the surface of the bodies being tested in the air stream and in the vicinity of these bodies can be undertaken. The results obtained so far in the simple preliminary investigations show that it is possible, even at a low Reynolds number, to obtain the density field in the neighborhood of a test body by optical means. Simple analytical expressions give the relation between density, pressure, velocity, and temperature. In addition to this, the interference measurement furnishes valuable data on the state of the boundary layer, that is, the sort of boundary layer (whether laminar or turbulent), as well as the temperature and velocity distribution.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1253 , Forschungsbericht; Rept-1167
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  • 34
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    Compression Shocks of Detached Flow (1947)
    In:  CASI
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    Publication Date: 2019-07-11
    Description: It is known that compression shocks which lead from supersonic to subsonic velocity cause the flow to separate on impact on a rigid wall. Such shocks appear at bodies with circular symmetry or wing profiles on locally exceeding sonic velocity, and in Laval nozzles with too high a back pressure. The form of the compression shocks observed therein is investigated.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1150 , Deutsche Luftfahrtforschung; Rept-1850
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  • 35
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    General Characteristics of the Flow through Nozzles at Near Critical Speeds (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The characteristics of the position and form of the transition surface through the critical velocity are computed for flow through flat and round nozzles from subsonic to supersonic velocity. Corresponding considerations were carried out for the flow about profiles in the vicinity of sonic velocity.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1147 , Deutsche Luftfahrtforchung; Rept-1992
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  • 36
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    Boundary Layer Theory (1949)
    In:  CASI
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    Publication Date: 2019-07-11
    Description: The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part. These actual flows show a special characteristic, denoted as turbulence. The character of a turbulent flow is most easily understood the case of the pipe flow. Consider the flow through a straight pipe of circular cross section and with a smooth wall. For laminar flow each fluid particle moves with uniform velocity along a rectilinear path. Because of viscosity, the velocity of the particles near the wall is smaller than that of the particles at the center. i% order to maintain the motion, a pressure decrease is required which, for laminar flow, is proportional to the first power of the mean flow velocity. Actually, however, one ob~erves that, for larger Reynolds numbers, the pressure drop increases almost with the square of the velocity and is very much larger then that given by the Hagen Poiseuille law. One may conclude that the actual flow is very different from that of the Poiseuille flow.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1218
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  • 37
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    Two-Dimensional Potential Flows (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Contents include the following: Characteristic differential equations - initial and boundary conditions. Integration of the second characteristic differential equations. Direct application of Meyer's characteristic hodograph table for construction of two-dimensional potential flows. Prandtl-Busemann method. Development of the pressure variation for small deflection angles. Numerical table: relation between deflection, pressure, velocity, mach number and mach angle for isentropic changes of state according to Prandtl-Meyer for air (k = 1.405). References.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1243 , Chapter 3,Technische Hochschule Dresden, Archives No. 44/3; Rept-44/3
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  • 38
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    Effects of Compressibility on the Flow Past Thick Airfoil Sections (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Six, 3-inch-chord symmetrical airfoil sections having systematic variations in thickness and thickness location were tested at Mach numbers near flight values for propeller-shank sections. The tests, the results of which are presented in the form of schlieren photographs of the flow past each model and pressure-distribution charts for two of the model, were performed to illustrate the effects of compressibility on the flow past thick symmetrical airfoil sections. Representative flow photographs indicated that at Mach numbers approximately 0.05 above the critical Mach number a speed region was reached in which the flow oscillated rapidly and the separation point and the location of the shock wave were unstable. Fixing the transition on both surfaces of the airfoil was effective in reducing these rapid oscillations. The pressure distributions showed that the section normal-force coefficients for thick airfoils were very erratic at subcritical speeds; at supercritical speeds the section normal-force coefficients for the thick airfoils became more regular. Drag coefficients showed that considerable drag decreases can be expected by decreasing the model thickness ratio.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L6J17a
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  • 39
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    Heat Transfer from High-Temperature Surfaces to Fluids. III - Correlation of Heat-Transfer Data for Air Flowing in Silicon Carbide Tube with Rounded Entrance, Inside Diameter of 3/4 Inch, and Effective Length of 12 Inches (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A heat-transfer investigation was conducted with air flowing through an electrically heated silicon carbide tube with a rounded entrance, an inside diameter of 3/4 inch, and an effective heat-transfer length of 12 inches over a range of Reynolds numbers up to 300,000 and a range of average inside-tube-wall temperature up to 2500 R. The highest corresponding local outside-tube-wall temperature was 3010 R. Correlation of the heat-transfer data using the conventional Nueselt relation wherein physical properties of the fluid were evaluated at average bulk temperature resulted in a separation of data with tube-wall-temperature level. A satisfactory correlation of the heat-transfer data was obtained, however, by the use of modified correlation parameters wherein the mass velocity G (or product of average air density and velocity evaluated at bulk temperature P(sub b)V(sub b)) in the Reynolds number was replaced by the product of average air velocity evaluated at the bulk temperature and density evaluated at either the average inside-tube-wall temperature or the average film temperature; in addition, all the physical properties of air were correspondingly evaluated at either the average inside-tube-wall temperature or the average film temperature.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-E9D12-Pt-3 , Rept-1115-Pt-3
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  • 40
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    Lecture Series "Boundary Layer Theory". Part I - Laminar Flows (1949)
    In:  CASI
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    Publication Date: 2019-07-10
    Description: In the lecture series starting today author want to give a survey of a field of aerodynamics which has for a number of years been attracting an ever growing interest. The subject is the theory of flows with friction, and, within that field, particularly the theory of friction layers, or boundary layers. A great many considerations of aerodynamics are based on the ideal fluid, that is the frictionless incompressibility and fluid. By neglect of compressibility and friction the extensive mathematical theory of the ideal fluid, (potential theory) has been made possible. Actual liquids and gases satisfy the condition of incomressibility rather well if the velocities are not extremely high or, more accurately, if they are small in comparison with sonic velocity. For air, for instance, the change in volume due to compressibility amounts to about 1 percent for a velocity of 60 meters per second. The hypothesis of absence of friction is not satisfied by any actual fluid; however, it is true that most technically important fluids, for instance air and water, have a very small friction coefficient and therefore behave in many cases almost like the ideal frictionless fluid. Many flow phenomena, in particular most cases of lift, can be treated satisfactorily, - that is, the calculations are in good agreement with the test results, -under the assumption of frictionless fluid. However, the calculations with frictionless flow show a very serious deficiency; namely, the fact, known as d'Alembert's paradox, that in frictionless flow each body has zero drag whereas in actual flow each body experiences a drag of greater or smaller magnitude. For a long time the theory has been unable to bridge this gap between the theory of frictionless flow and the experimental findings about actual flow. The cause of this fundamental discrepancy is the viscosity which is neglected in the theory of ideal fluid; however, in spite of its extraordinary smallness it is decisive for the course of the flow phenomena.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1217
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  • 41
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    Tests of a Full-Scale Model of the Republic XF-91 Airplane in the Ames 40- by 80-Foot Wind Tunnel. Force and Moment Data (1949)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Wind-tunnel tests of a full-scale model of the Republic XF-91 airplane having swept-back wings and a vee tail were conducted to determine both the stability and control characteristics of the model longitudinally, laterally, and directionally. Configurations of the model were investigated involving such variables as external fuel tanks, a landing gear, trailing-edge flaps, leading-edge slats, and a range of wing incidences and tail incidences.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SA9C04
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  • 42
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    Liquid cooled helmet (1979)
    In:  CASI
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    Publication Date: 2019-07-12
    Description: Liquid cooled helmet comprising a cap of flexible material adapted to fit the head of a person, cooling panels mounted inside the cap forming passageways for carrying a liquid coolant, the panels being positioned to engage the cranium and neck of a person wearing the helmet, inlet and outlet lines communicating with the passageways, and releasable straps for securing the helmet about the neck of the wearer.
    Keywords: Fluid Mechanics and Thermodynamics
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  • 43
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    Aseptic fluid transfer system (1977)
    In:  CASI
    Details
    Publication Date: 2019-08-16
    Description: A method and means is provided, which permits the transfer of fluids between separate detached containers, in a manner which preserves the sterility of the fluids during and after their transfer.
    Keywords: Fluid Mechanics and Thermodynamics
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  • 44
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    Nonstationary Gas Flow in Thin Pipes of Variable Cross Section (1948)
    In:  CASI
    Details
    Publication Date: 2019-08-16
    Description: Characteristic methods for nonstationary flows have been published only for the special case of the isentropic flow up until the present, althought they are applicable in various places to more difficult questions too. This report derives the characteristic method for the flows which depend only on the position coordinates and time. At the same time the treatment of compression shocks is shown.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1196 , Zentrale fuer Wissenschaftliches Berichtswesen der Luftfahrtforschung des Generalluftzeugmeisters (ZWB); 1744
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  • 45
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    Investigation of Flow in a Centrifugal Pump (1946)
    In:  CASI
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    Publication Date: 2019-08-16
    Description: The investigation of the flow in a centrifugal pump indicated that the flow patterns in frictional fluid are fundamentally different from those in frictionless fluid. In particular, the dead air space adhering to the section side undoubtedly causes a reduction of the theoretically possible delivery head. The velocity distribution over a parallel circle is also subjected to a noticeable change as a result of the incomplete filling of the passages. The relative velocity on the pressure side of the vane, which for passages completely filled with active flow would differ little from zero even at comparatively lower than normal delivery volume, is increased, so that no rapid reverse flow occurs on the pressure side of the vane even for smaller delivery volume. It was established, further, that the flow ceases to be stationary for very small quantities of water. The inflow to the impeller can be regarded as radial for the operating range an question. The velocity triangles at the exit are subjected to a significant alteration in shape ae a result of the increased peripheral velocity, which may be of particular importance in the determination of the guide vane entrance angle.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1089 , Mitteilungen des Hydraulischen Instituts der Technischen Hochschule; 4; 1-27
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  • 46
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    Reclaiming Waste Heat (1976)
    In:  CASI
    Details
    Publication Date: 2019-08-16
    Description: 'Air-O-Space' heater, based on spacecraft heat, requires no fuel other than electricity to run fan. Installed in chimney flue, heat pipes transfer heat from waste hot gases (but not the gases themselves) to fresh air blown across the other end of the pipes. It can transport roughly 500 times the heat flux of the best solid conductors with a temperature drop of less than 3 degrees per foot. This instrument has also been used by Kin-Tek Laboratories Inc. to produce an instrument to calibrate gas analyzers for air-pollution monitoring.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: Spinoff 1976; 75
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  • 47
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    Calculation of Turbulent Expansion Processes (1945)
    In:  CASI
    Details
    Publication Date: 2019-08-15
    Description: On the basis of certain formulas recently established by L. Prandtl for the turbulent interchange of momentum in stationary flows, various cases of "free turbulence" - that is, of flows without boundary walls - are treated in the present report. Prandtl puts the apparent shearing stress introduced by the turbulent momentum interchange. This present report deals first with the mixing of an air stream of uniform velocity with the adjacent still air, than with the expansion or diffusion of an air jet in the surrounding air space.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1085 , Zeitschrift fuer angewandte Mathematik und Mechanik; 6; 1-12
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  • 48
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    Pressure Distribution Measurements on a Turbine Rotor Blade Passing Behind a Turbine Nozzle Lattice (1947)
    In:  CASI
    Details
    Publication Date: 2019-08-15
    Description: As a turbine rotor turns, the blades traverse the wake zones of the nozzle vanes. A periodic fluctuation of the pressure distribution around the circumference of the rotor blade is therefore caused. It was desired to investigate quantitatively this effect. At the same time, the magnitude of the force acting upon one profile of the rotor-blade lattice at various positions of this lattice relative to the nozzle lattice was to be determined.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1173 , Reports of the Lattice Conference: Berichte der Gittertagung; Mar 27, 1944 - Mar 27, 1944; Brunswick,; Germany|Berichte der Gittertagung; 95-100; M325/44g
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  • 49
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    An Analytical Investigation of the Heat Losses from a U.S. Navy K-Type Airship (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: The heat losses from the envelope surface of a U.S. Navy K-type airship are evaluated to determine if the use of heat is a feasible means of preventing ice and snow accumulations on lighter-than-air craft during flight and when moored uncovered. Consideration is given to heat losses in clear air (no liquid water present in the atmosphere) and in probable conditions of icing and snow. The results of the analysis indicate that the amount of heat required in flight to raise the surface temperature of the entire envelope to the extent considered adequate for ice protection, based on experience with tests of heavier-than-air craft, is very large. Existing types of heating equipment which could be used to supply this quantity of heat would probably be too bulky and heavy to provide a practical flight installation. The heat requirements to provide protection for the nose and stern regions in assumed mild to moderate icing conditions appear to be within the range of the capacity of current types of heating equipment suitable for flight use. The amount of heat necessary to prevent snow accumulations on the upper surface of the airship envelope when moored uncovered under all conditions appear to be excessive for the heating equipment presently available for flight use, but could possibly be achieved with auxiliary ground heating equipment.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SA6L20
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  • 50
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    Adsorption air conditioner (1979)
    In:  CASI
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    Publication Date: 2019-07-12
    Description: A solar powered air conditioner using the adsorption process is constructed with its components in a nested cylindrical array for compactness and ease of operation.
    Keywords: Fluid Mechanics and Thermodynamics
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  • 51
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    High pressure, high temperature transducer (1977)
    In:  CASI
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    Publication Date: 2019-07-12
    Description: The pressure measurement system utilizes two bourdon tubes with an active side connected to a test specimen and a reference side connected to an outside source. The tubes are attached to a single extensometer measuring relative displacement. The active side deflects when gases vent a specimen failure. The reference side is independently pressurized to a test pressure and provides a zero reference while providing a pressure calibration reference for the active side. The deflection noted by the active side at specimen failure is duplicated on the reference side by venting until an appropriate magnitude of pressure versus deflection is determined. In this way the pressure which existed inside the specimen prior to failure can be determined.
    Keywords: Fluid Mechanics and Thermodynamics
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  • 52
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    Passive cooler (1977)
    In:  CASI
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    Publication Date: 2019-07-12
    Description: A three stage passive cooler for use in a spacecraft for cooling an infra-red detector includes a detector mounting cold plate for mounting the detector directly to the telescope optics. The telescope optics collect and direct the infra-red radiation from the earth, for example, to the infra-red detector, and are mounted directly to the spacecraft. The remaining stages of the cooler are mounted with thermal insulators to each other and to the spacecraft at separate locations from the detector mounting cold plate.
    Keywords: Fluid Mechanics and Thermodynamics
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  • 53
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    Fuel cell heat and mass plate (1976)
    In:  CASI
    Details
    Publication Date: 2019-08-15
    Description: A novel method and apparatus is provided for controlling heat and mass inventory in a fuel cell. Heat and mass, e.g. water, generated in the cell are removed by heat transfer and capillary action.
    Keywords: Fluid Mechanics and Thermodynamics
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  • 54
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    Tests of Cascades of Airfoils for Retarded Flow (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Test results are present for cascades of airfoils in retarded flow and increasing pressure as corresponds to the case of the impeller of an axial propeller pump and propeller fan.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1190 , Transactions of the Society of Mechanical Engineers; 3; 13; 334-344
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  • 55
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    Investigation of Turbulent Mixing Processes (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: With water as driving medium and delivered medium in a device similar to a simple jet apparatus, the pressure and velocity fields of the mixing zone were explored with a pitot bar; the ratio of delivered to driving volume ranged between the values 0, 1, 2, and 4. An attempt was also made to analyze the mixing flow mathematically by integration of the equation of motion, with the aid of conventional formulas for the turbulent shearing stress, but this succeeded only approximately for the very simplified case that a driving jet is introduced in an unlimited parallel flow, while the pressure over the whole mixing field is assumed to be constant. In spite of these dissimilar assumptions for the theory and the experiment, the form of the measured and the computed velocity profiles indicates a very high degree of approximation. The pressure rise, which was approximated by Flugel's formulas, disclosed good agreement with the measured values.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1096 , Forschung auf dem Gebiete des Ingenieurwesens; 12; 1; 16-30
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    On Combustion in a Turbulent Flow (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The characteristics introduced by the turbulence in the process of the flame propagation are considered. On the basis of geometrical and dimensional considerations an expression is obtained for the velocity of the flame propagation in a flow of large scale of turbulence.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1110 , Journal of Technical Physics; 13; 10-Sep
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    Flow Investigation with the Aid of the Ultramicroscope (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: On the basis of photographic pictures the laminar flow at a pipe inlet was measured and compared with other measurements and computational results. The test setup is described in detail, and a series of the pictures obtained for turbulent flow is given.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1109 , Forschung auf dem Gebiete des Ingenieurwesens; 8; Pt 1; 42-47
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    The Effect of Turbulence on the Flame Velocity in Gas Mixtures (1947)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The present report deals with the effect of turbulence on the propagation of the flame. Being based upon experiments with laminar as well as turbulent Bunsen flames, both the physico-chemical and the hydro-dynamical aspects of the problem are analyzed. A number of new deductions, interesting from the point of view of engine combustion and other very rapidly changing flame reactions, are made.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1112 , Zeitschrift fuer Elektrochemie und Angewandte Physikalische Chemiw; 46; 11; 601-626
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    CSM/LM Spacecraft Operational Data Book. Volume 3: Mass Properties Data Book (1971)
    In:  CASI
    Details
    Publication Date: 2019-11-09
    Description: No abstract available
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NASA-TM-X-69016 , SNA-8-D-027-VOL-3-REV-3 , JSC-E-DAA-TN75190
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    Determination of the molecular weight spread of narrow peaks in the gel-permeation chromatograms of nitric acid-degraded polyethylene (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 35-45 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method for the determination of the molecular weight spread in the narrow peaks in the GPC chromatograms of nitric acid-degraded polyethylene is presented. It is found that polar endgroups added to the polymer chains during scission cause the peaks to be broader than those of paraffins with the same molecular weight spread. After allowing for this extra instrumental broadening, estimates are made of the molecular weight spread for unannealed and annealed single crystals of polyethylene and bulk polyethylene as a function of degradation time. It is proposed that after long degradation times the molecular weight spread is a measure of fluctuations in the original crystalline lamellar thickness.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080103
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    Structure of a typical amine-cured epoxy resin (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 417-436 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A technique for estimating Mc, the molecular weight between crosslinks, of amine-cured epoxy resins is described. The technique is based upon the stoichiometry of the curing reaction and the amount of primary amino and epoxy groups remaining in the polymer at a given time. The Mc values so calculated are shown to be consistent with Mc results obtained from separate measurements of swelling and the polymer-solvent interaction parameter χ1 for the range of polymer concentration in which both measurements could be obtained. A means of estimating the relative reaction rates of the primary and secondary amino groups with the epoxy groups is given. Under proper curing conditions the amine-epoxy reaction goes very nearly to completion. The presence or absence of an exotherm has no noticeable effect on the course of the reaction between bisphenol A-epichlorohydrin (Epon 828) and methylene dianiline.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080308
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    ESR studies on gamma-irradiated (KPO3)n crystals (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 447-453 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two types of (KPO3)n crystals have been obtained: transparent crystals and semitransparent crystals that grew in the neighborhood of the wall of the crucible. In the latter type of crystals, four kinds of radicals, denoted B, C, D, and E, are observed by ESR measurements at 77°K on crystals irradiated with γ-rays at the same temperature. The probable structure of B, C, and D radicals is concluded to be —O—PO̊2—O— from their g values and hyperfine constants (the superscript circle indicates a hole trapped in the radical). When these crystals are heated to room temperature, the ESR spectra of B, C, and D radicals disappear and the spectrum of another radical appears. This radical, designated A, has the possible structure —O—ṖO2. The assumption that B radicals thermally decompose into A radicals is confirmed by experiment. With the transparent crystals, C, D, and E radicals are observed at low temperature, but only E radicals are stable at room temperature. The structure of the E radical is thought to be\documentclass{article}\pagestyle{empty}\begin{document}${\rm \hbox{---}O \hbox{---}PO}_2{{_\circ} \atop ^{\hbox{---}}} {\rm PO}_2 {\rm \hbox{---}O\hbox{---}} $\end{document}, but more detailed studies are required.
    Additional Material: 4 Ill.
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    Addition polymers: Formation and characterization. D. A. SMITH, ed., Plenum Press, New York, 1968. pp. 492. $22.00 (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 482-482 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080314
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    Comments on light-scattering measurements (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 513-518 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080403
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    Dilute solution parameters of polymethylphenylsiloxamers (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 541-554 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dilute solution parameters were determined for polymethylphenylsiloxamer fractions (5 × 104 〈 M 〈 1.5 × 106) in toluene, cyclohexane, and diisobutylamine (θ ≈ 30.4°C). The data are interpreted by the procedure suggested by Flory and Fox. Minor deviations from theory are noted. Polymers from both cis- and trans-cyclotrisiloxanes were investigated. The major portion of the work, however, was concentrated on fractions derived from the trans form. From the data obtained, a characteristic ratio of dimensions (r02/rof2)½ of 1.56 was determined. The hydrodynamic parameter Φ was determined to be (2.0 ± 0.3) × 1021. The appropriate model for the polymer is indicated to be the impermeable random coil with slight hindrance to rotation about backbone skeletal bonds.
    Additional Material: 9 Ill.
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    Effect of bending and stretching of polyethylene strips on the adsorption of surface-active substances (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 595-603 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The adsorption of tritium-labeled sodium stearate and 35S-labeled sodium dodecylsulfate from aqueous solution on bent and on stretched polyethylene strips was directly measured. The amount of adsorption increased from 2.5 to 4.5 times on surfaces of various polyethylene samples stretched from 5.2 to 5.3 times the original length. For one sample, adsorption increased 8 and 2.5 times, respectively, on the convex and concave surfaces of a bent strip. Autoradiographs of the strips taken after adsorption revealed the appearance of both homogeneous and heterogeneous adsorption on the stretched surface of the polyethylene. The electron micrographs of the strips showed that many small fissures, about 1-5μ in length, formed on their surfaces after the strips were bent or stretched. Enhanced adsorption of the surface-active substance along these fissures was suggested. On the basis of these observations, it is proposed that in stretching or bending, fissures increase adsorption of the detergent, and the adsorption in turn promotes further development of fissures. Thus, bending and adsorption mutually promote the growth of fissures which finally result in failure of the polyethylene.
    Additional Material: 7 Ill.
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    Normal stress and shear stress in a viscoelastic liquid under oscillatory shear flow (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 371-381 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Normal stress and shear stress of concentrated polystyrene solutions in a chlorinated diphenyl were measured under steady flow and oscillatory shear flow in a Weissenberg rheogoniometer. The normal stress difference was observed to oscillate at double the frequency of the applied shear strain with amplitude proportional to the square of the applied amplitude, while the shear stress was found to oscillate at the same frequency with amplitude proportional to the applied amplitude. A theoretical relation between the displacement of the oscillatory normal stress difference from zero level and the dynamic modulus derived by Lodge and other investigators was confirmed experimentally, and the theoretical predictions of Coleman and Markovitz concerning the relation among steady-flow normal stress difference and dynamic modulus were also confirmed. However, the theoretical predictions of Lodge, of Spriggs, Huppler and Bird, and of Williams on the relation between the amplitude and phase of oscillatory normal stress and those of oscillatory shear stress did not agree with experimental results.
    Additional Material: 11 Ill.
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    Single crystals of high polymers by film formation (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 47-59 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A simple method of preparing thin uniform films of high polymers has been examined for growing single crystals from solution. Single crystals of polyethylene, polypropylene, polybutene-1, polyacrylonitrile, and cellulose triacetate have been obtained by this method. Different stages of growth reveal different growth features that are also obtained from solutions of these polymers by changing temperature and concentration.
    Additional Material: 19 Ill.
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    Isomorphic interactions of ethylenic polymers and paraffin wax (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 81-87 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The high degree of flexibility of blends containing minor amounts of partly crystalline copolymers of ethylene and vinyl acetate in paraffin wax seems to be a manifestation of some type of interaction. Low-angle x-ray diffraction of such blends showed a new long spacing intermediate in length between the polymer long spacing and the c axis length of the wax unit cell. This new long spacing appears to be a consequence of isomorphism involving cocrystallization of polymeric ethylene sequences and wax molecules. A lesser type of isomorphic interaction, epitaxy, occurs in polyethylene-wax blends: wax overgrows crystals of already crystallized polyethylene in the same orientation without a change in its c axial dimension.
    Additional Material: 2 Ill.
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    Thermoluminescence in hydrocarbon polymers (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 143-147 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080111
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    Structural changes in polystyrene films and corresponding changes in their fluorescence spectra (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 161-165 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080114
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    Conformational characteristics of polymorphous optically active macromolecules: A statistical zigzag model (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 177-190 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The conformational properties of optically active macromolecules are considered. A statistical zigzag model is used for the calculation of averaged physical properties. The macromolecule is considered to consist of segments of two different types with a statistical distribution of lengths. The expressions for the mean square of the end-to-end vector h2 and the dipole moment μ2 and also of the mean optical anisotropy ΔA and the anisotropy of the optical rotation tensor ΔG were obtained in the cases of freely jointed and freely rotating segments. The equations obtained were applied to the problem of the helix-coil transition. In the case of poly-α-olefins the values of h2, μ2, and ΔA, are larger than corresponding values for typical optically inactive macromolecules. The anisotropies ΔA and ΔG of two poly-α-olefins of similar structures were calculated. The polarizability theory of optical activity was used for the calculations of ΔG. The values obtained for ΔA are similar, but the values of ΔG differ markedly. The possibility of obtaining valuable information about the structure of optically active macromolecules in solution by a study of anisotropy of the optical rotation tensor is considered.
    Additional Material: 1 Ill.
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    Lamellar and interlamellar structure in melt-crystallized polyethylene. I. Degree of crystallinity, atomic positions, particle size, and lattice disorder of the first and second kinds (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 243-276 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An x-ray diffraction method for the simultaneous determination of crystallinity (including intracrystalline defects), effective Debye-Waller factors, and atomic positions has been developed and applied to semicrystalline polyethylene. It was found that this material unambiguously constitutes a two-phase system. Measurements of intracrystalline lattice disorder in the chain direction and perpendicular to the chain direction show these to be in the ratio 1:2.5. Lattice disorder was principally of the first kind. Paracrystalline disorder in the [110] direction was less than 2.4% at all experimental conditions. Results include measurements of degree of crystallinity, particle size, space group, and unit cell parameters and variation of these quantities with crystallization temperature, ambient temperature, and time.
    Additional Material: 13 Ill.
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    Contribution à l'étude de l'ionisation des films insolubles de polyélectrolytes stéréoréguliers (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 817-832 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The surface potentials of monolayers of poly(methacrylic acid) (PMA) have been studied as a function of the pH of the subsolution. The influence of the macromolecular configuration on the properties of the ionizable groups was more particularly investigated. Orientation of molecules in the monolayer may be imposed by the stereoregularity of PMA (isotactic, atactic) and by the nature of the interface (air-water, cyclohexane-water). The results are analyzed in terms of theories of the ionic double layer (Gouy model, Donnan equilibrium) which permit the determination of the degree of ionization α of the film. The value of α gives indications about the orientation of specific groups of the macromolecular chain, i.e., of the ionized monomer units. Indeed, at the air-water interface, the film of isotactic PMA is more acid than that of the atactic sample, and at the cyclohexane-water interface, the degree of ionization is greater than at the air-water interface. These properties are the consequence of a modification of orientation of the hydrophilic groups with respect to the aqueous phase as a function of the stereoregularity of the sample and the nature of the interface. The variation of α with the pH of the substrate phase may be used to calculate an intrinsic dissociation constant Ks° of the molecules in the film. The value of Ks° is not modified by spreading conditions and remains very similar to that obtained in solution.
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    Yield condition and propagation of Lüders' lines in tension-torsion experiments on poly(vinyl chloride) (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 893-901 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We have derived from the Eyring theory of non-Newtonian flow a yield condition which is valid for an arbitrary state of stress. Experimental data obtained in simple axial compression tests show the influence of the hydrostatic stress on the yielding of poly(vinyl chloride). This fact confirms the proposed condition and disproves the von Mises criterion. Tension-torsion tests performed on thin tubes lead to results which fit our condition fairly well. The pattern of Lüders' lines appearing on the surface of thin tubes subjected to simple tension, simple shear, and tension-torsion are parallel to the direction where the value of the normal stress is equal to the hydrostatic stress.
    Additional Material: 8 Ill.
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    Relation between the network structure and dynamic mechanical properties of a typical amine-cured epoxy polymer (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 437-445 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic mechanical properties of a series of epoxy polymers of known network structure have been investigated. It was shown that the distance between crosslinks could be predicted from either the shift in the glass transition temperature Tg or by use of the dynamic modulus above Tg. The front factor in the equation of state for rubber elasticity was near unity for stoichiometric equivalence of epoxy and amine and increased slowly with excess of either component.
    Additional Material: 4 Ill.
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    A dynamic approach to diffusion and permeation measurements (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 467-479 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A dynamic method for investigating the mechanism of permeation and diffusion through polymers has been explored. The permeation cell consists of two compartments separated by the membrane. The permeant (gas, vapor, or liquid) is introduced into one compartment; a carrier gas (helium) flows at constant rate through the other and sweeps the permeant which diffuses through the membrane to the thermal conductivity detector. Both compartments are at atmospheric pressure; thus no or little membrane support is required, and leakage problems are minimal. Moreover, the same membrane can be used over a wide temperature range and for diverse permeants. The detector signal is at any instant proportional to the permeation rate. A simple mathematical formalism for deriving the diffusion coefficient from the transient permeation rates has been developed. The measured diffusion and permeability coefficients of CO2, O2, and N2 through low-density polyethylene closely agree with literature values. Permeation of hexane and benzene through polyethylene follows a complex diffusion law, and the rate depends on the thermal history of the system. The dynamic method is particularly suited to the study of transitions in polymers. Changes in permeation rates, usually occurring at transition points, can easily be discovered by slow temperature scanning of the system.
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    NMR study of molecular motion in oriented long-chain alkanes. II. Oriented mats of polyethylene single crystalsPresented at the Meeting of the American Physical Society, Berkeley, Calif., March 1968. (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 771-789 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of the NMR second moment of a uniaxially oriented sample of polyethylene single crystals in the range of temperatures from -196°C to 130°C and its dependence on the alignment angle γ between the orientation axis (preferential direction of the molecular chains) and the NMR magnetic field are presented. The experimental results are discussed mainly with respect to the high temperature relaxation, called the α process, in polyethylene. They are compared to theoretical predictions made for a number of mechanisms of molecular motion in Part I of this work. Only one of the mechanisms considered is found to be in quantitative agreement with experiment, the mechanism here referred to as flip-flop motion. This consists of thermally activated rotational jumps of the crystalline chain segment between folds around its axis between two equilibrium sites in the lattice. Each rotational jump through 180° is accompanied by a shift of the molecule along its axis by one CH2 group. The discussion of the low-temperature relaxation of polyethylene, the γ process, is based partly on the above measurements and partly on measurements of second moments for unoriented polyethylene samples varying widely in morphology and noncrystalline content. The decrease of the second moment observed with these samples between -196°C and 20°C is taken as a measure of the intensity of the γ process. A linear correlation is found between the decrease in the second moment, designated ΔS, and the noncrystalline content, 1 - αm; this can be represented by ΔS = 1.4 + 22.1(1 - αm). It is shown that neither the crankshaft mechanism not the kink mechanism is able to account quantitatively for this result. The model of a chain end moving in a vacancy fails to adequately describe the angle dependence of ΔS in oriented polyethylene single crystals. The “sandwich model” of a polyethylene single crystal, in which the crystalline core is covered by noncrystalline surface layers, is in better agreement with observations.
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    The scattering of light and other electromagnetic radiation by Milton Kerker. Academic Press, New York, 1969. 666 + xv pp. $33.50 (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 813-813 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080514
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    Crystallization kinetics of dilute polyethylene solutions (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 869-882 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystallization kinetics of a high molecular weight fraction of linear polyethylene was studied in dilute solutions of p-xylene, n-hexadecane, and decalin by dilatometric methods. For all solvents and temperatures, the experimental isotherms could be quantitatively described by the Avrami formulation for the complete transformation. This result is unique in the realm of polymer crystallization, since marked deviations from this theory are usually observed in more concentrated systems. The Avrami exponent is found to be n = 4 in all cases. The temperature coefficients of the rate constants are indicative of a nucleation controlled process. The data fit either a two-dimensional or three-dimensional nucleation mode, and a discrimination can not be made between these two cases. The interfacial free energies are found to be independent of the solvent medium. It is also shown that, irrespective of the type of nucleation control governing the kinetics, the same type governs the crystallite thickness of the lamella-like crystals that are formed.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080604
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    Mechanical properties of natural rubber vulcanizates in finite deformationPresented at the 17th Symposium on Polymer Chemistry, Japan, Ehime University, Matsuyama, Oct. 24, 1968. (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 903-919 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mechanical properties of four kinds of natural rubber vulcanizates differing in vulcanization conditions, and consequently in degree of crosslinking (having values of the Mooney-Rivlin constant C1 ranging from 0.68 to 1.98) were observed under orthogonal biaxial stretching in a range of strain invariants Ii from 3.4 to 9.0 (extension ratios λi from 0.7 to 3.0). The results obtained were analyzed by two methods. One method employed the Valanis-Landel postulate that the strain-energy function W(λ1, λ2, λ3) is a separable symmetric function of the principal extension ratios, i.e., W(λ1,λ2,λ3) = w(λ1) + w(λ2) + w(λ3); the other utilized the contour plots of ∂W(I1, I2)/∂I1 and ∂W(I1, I2)/∂I2 surface within the (I1, I2) domain. The postulate for W was examined in detail with good agreement with experimental results. The dependences of ∂W(I1, I2)/∂I1 and ∂W(I1, I2)/∂I2 surfaces on the degree of crosslinking and temperature were further investigated, with the following conclusions. The surfaces have fairly steep slopes for the region of relatively small deformation (i.e., I1 〈 5) and become flat with increasing Ii for all the test specimens. The slope becomes less steep with decreasing degree of crosslinking. The values of ∂W/∂I1 increase linearly and the ∂W(I1,I2)/∂I2 surface becomes flat, both with increasing temperature: i.e., the temperature dependence of ∂W/∂I1 further depends on Ii. The ∂W(I1,I2)/∂I2 surface has a maximum near 40°C.
    Additional Material: 16 Ill.
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    Measurements of the relaxation spectra of unplasticized poly(vinyl chloride) melts (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 979-990 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We have measured the relaxation modulus in the temperature range 150-220°C of two samples of poly(vinyl chloride) resin with different molecular weights. The data were treated by the principle of reduced variables to yield composite curves. The shift factors (aT) when plotted against reciprocal temperature gave good straight lines from which apparent activation energies were obtained. An apparent activation energy of 50 kcal/mole was obtained for both samples. A relaxation spectrum for each resin was calculated from the relaxation modulus data. These spectra showed a marked molecular weight dependence. The spectra were in the range characteristic of the terminal zone of the entanglement plateau. Zero-shear-rate viscosities were obtained from the integration of relaxation modulus plots. From extrapolation of capillary viscosity data it is shown that the viscosity of the higher molecular weight resin used in this study does not approach its zero-shear value until shear rates less than 10-3 sec-1 are reached. The effect of supermolecular flow units is briefly discussed.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080612
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    Relation of initial supermolecular organization in crystalline polymer systems to the organization produced by stretching (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1015-1026 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An investigation of small-angle scattering produced by polarized light from stretched and annealed polymer systems containing spherulites yields information on the supermolecular transitions that occur during such treatment. A series of semicrystalline polymer systems (films, fibers) show that stretching leads to deformation of spherulites and subsequent transformation to an orientational supermolecular order. The size of the single element C2 of the supermolecular order in the direction of stretching, determined from the distance between the layer lines of the scattering pattern, is related to the diameter D0 of the initial spherulites by the relation C2 = KD0λs, where λ, is the draw ratio of the macrosystem and K is a parameter determining the deformability of the spherulites. For polyethylene at room temperature K is unity and for polychloroprene it is 1.2. Changes of C2 after annealing and restretching of the systems also obey this ratio.
    Additional Material: 9 Ill.
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    Structural studies of pressure-crystallized polymers. I. Heat treatment of oriented polymers under high pressure (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1073-1087 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A convenient pressure apparatus was designed for crystallization of high polymers under hydrostatic pressure up to 5000 atm. Melt crystallization as well as heat treatment under various temperatures and pressures was carried out on several polymers, and the effects of pressure on the molecular and crystal structures of the samples are discussed. Heat treatment of syndiotactic polypropylene under high pressure yields a new crystal modification rather than the previously known helix and planar zigzag modifications. Of the three modifications of poly(vinylidene fluoride), modification III was found as a high-pressure phase for specimens in the unoriented state, while modification I was obtained as the most stable one on heat treatment of oriented specimens under high pressure. Heat treatment under high pressure converts ordinary isotactic poly-4-methylpentene-1 with a lower density than the noncrystalline value, to a new crystal modification with higher density. As is reasonable, the dense modification is stable in a high-pressure range. For these three cases, the orientation of specimens was found to remain unchanged during the transitions, which must therefore occur in the solid state.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080705
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    Scattering of light by disordered spherulites (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1137-1157 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The scattering of light by a two-dimensional spherulite of radius R is calculated when there is disorder of optic axis orientation with respect to the radius. Special cases are considered when (1) the disorder occurs in the radial direction only, (2) the disorder occurs in the angular direction only, (3) there is combined radial and angular disorder, and (4) the optic axis makes a constant angle with the radius but there is disorder in the twist angle about the axis. In all of these calculations, a correlation function for disorder is defined and the scattering pattern depends on the ratio of the associated correlation distance to the size of the spherulite. With decreasing correlation distance, the azimuthal dependence of the scattering becomes less and there is a change in the variation of scattered intensity with scattering angles in a manner dependent upon the type of disorder.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080709
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    Methods of description of orientation in polymers (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1187-1194 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The nonrandom orientational distribution of structural units, such as crystallites and chain segments, prevailing in an anisotropic bulk polymer sample can be represented fully by an orientation distribution function. Measurements of fluorescence polarization and wide-line NMR are, in principle, capable of yielding information on the moments of the distribution function up to the fourth order. This work presents the method of analysis required to determine these moments. For this purpose, the distribution function is expanded in a series of generalized spherical harmonies. The method is an extension of a similar technique previously proposed for analysis of x-ray diffraction data for determination of a complete crystallite orientation distribution function.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080713
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    Diffusion of radioactively tagged 1,1-diphenylethane and n-hexadecane through rubbery polymers: Dependence on temperature and dilution with solvent (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 991-998 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The diffusion of 1,1-diphenylethane in trace amounts through eight rubbery polymers has been studied by radioactive tagging of this penetrant with 14C. For several polymers, the dependence on temperature and on dilution (swelling) by untagged diphenylethane was investigated. In the diluted systems, tagged n-hexadecane was also used as a trace penetrant. The temperature and concentration dependences were interpreted rather successfully in terms of the free volume. In comparing different polymers, with a 4000-fold range of diffusion coefficients, the translatory friction coefficient of 1,1-diphenylethane was found to be proportional to that of n-hexadecane to the power 1.06. This is interpreted qualitatively by the free volume concept to indicate a slightly less efficient mobility mechanism for the diphenylethane.
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    Dielectric relaxation and molecular motion in poly(vinylidene fluoride) (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1057-1072 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric properties of poly(vinylidene fluoride) have been studied in the frequency range 10 Hz to 100 kHz at temperatures between -196 and 150°C. Three dielectric relaxations were observed: the α relaxation occurred near 130°C, the β near 0°C, and the γ near -30°C at 100 kHz. In the α relaxation the magnitude of loss peak and the relaxation times increased not only with increasing lamellar thickness, but also with decrease of crystal defects in the crystalline regions. In the light of the above results, the α relaxation was attributed to the molecular motion in the crystalline regions which was related to the lamellar thickness and crystal defects in the crystalline phase. In the β relaxation, the magnitude of the loss peak increased with the amount of amorphous material. The relaxation times were independent of the crystal structure and the degree of crystallinity, but increased slightly with orientation of the molecular chains by drawing. The β relaxation was ascribed to the micro-Brownian motions of main chains in the amorphous regions. The Arrhenius plots were of the so-called WLF type, and the “freezing point” of the molecular motion was about -80°C. The Cole-Cole distribution parameter of the relaxation time α increased almost linearly with decreasing temperature in the temperature range of the experiment. The γ relaxation was attributed to local molecular motions in the amorphous regions.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080704
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    Scattering of light by films having nonrandom orientation fluctuations. II (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1127-1136 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The theory for scattering of light from films in which the orientation correlation between two scattering elements depends upon the angle β between the optic axes and the vector connecting the two elements is extended. A delta-function type dependence is assumed in which the correlation is strongest when β equals some preferred value β0. Calculated results of scattered intensities are shown to be similar to experimental observations.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080708
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    ESR and electrical conduction in polypropiolamide (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1159-1168 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: ESR and electrical conductivity measurements have been made on a recently prepared polymer, polypropiolamide. The polymer was obtained as a fine powder which exhibited a nearly Lorentzian line with a width between derivative maxima of 5.2 ± 0.1 gauss and a g value of 2.0036 ± 0.0005. The signal intensity increased with increasing molecular weight. The signal was retained in a dilute solution in formic acid with a slight narrowing of the line. Permanent changes were produced in the spectra at room temperature by heat treatments of the polymer at temperatures up to 800°K. The changes were similar for samples sealed in tubes containing air, dry nitrogen gas and a vacuum of 3 × 10-5 mm of Hg. Spectra obtained at temperatures up to 500°K showed no dependence on the presence or absence of oxygen in the ambient atmosphere. The deresistance of pressed pellets of the polymer was measured in the temperature range 450°K to 525°K, and the results were described by the relation R = R0cE/kT. The activation energy E had a value of 1.2 ± 0.2 ev and the resistivity at 500°K was approximately 1013 ohm-em. The ESR signal is attributed to an intrinsic property of the polymer which is associated with a conjugated bond system along the polymer backbone. Neither the activation energy nor the magnitude of the resistivity suggest that the delocalized electrons associated with the conjugated bond system have produced unusual electrical characteristics in the polymer.
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    Molecular weight distribution for diactive polymers formed by instantaneous initiation, transfer to monomer, and no termination (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1235-1237 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160080717
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    Liquid-liquid phase separation in multicomponent polymer solutions. IX. Concentration-dependent pair interaction parameter from critical miscibility data on the system polystyrene-cyclohexane (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1261-1278 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Critical miscibility data obtained from measurements of phase-volume ratios have been used to calculate the concentration dependence of the pair interaction parameter for the system polystyrene-cyclohexane. The measured temperature and concentration ranges are 11-30°C and 4-18% polymer by weight, respectively. With the Gibbs free energy of mixing expressed in polymer segment mole fractions, x*, the pair interaction parameter is g(x*, T) = 0.4961 + 71.92/T + 0.2312x* + 0.0750x*2. In a polymer volume fraction formulation the parameter is g(ϕ, T) = 0.4099 + 90.65/T + 0.2064 ϕ + 0.0518 ϕ2, which approximates to χ(ϕ, T) = 0.2035 + 90.65/T + 0.3092 ϕ + 0.1554 ϕ2. Comparison of the temperature and concentration dependence with that obtained by other authors shows very good agreement, even when extensive extrapolations in temperature and concentration are applied. The present function is believed to be the most accurate. Solutions of mixtures of two narrow-distribution polystyrenes in cyclohexane show separation into three liquid phases under the exact conditions predicted by theoretical calculation with the present pair-interaction function.
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    Spectroscopic study of the formation and structure of polyselenacyclobutane (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1279-1289 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Selenacyclobutane (trimethylene selenide) readily undergoes photochemical reaction to give polymeric products. Also, the material polymerizes rapidly when the polycrystalline solid film liquifies on a salt substrate in vacuum. Upon polymerization of the sample, infrared and Raman spectra exhibit profound changes which definitely establish ring cleavage. The Raman spectra of the polymer reveal strong C-Se stretching peaks but little or no scattering in the region of Se-Se stretching, strongly suggesting that the polymerization process proceeds in a regular head-to-tail fashion. An EPR study of the monomer exposed to ultraviolet radiation at -180°C supports this fact, since the resulting spectrum is indicative of an intermediate radical species, (CH2CH2-CH2Se)n., where n is sufficiently large that the terminal electrons do not interact. No triplet spectra were observed. Molecular oxygen apparently plays an important role in the polymerization kinetics, since it is found that degassed samples of the substance, in contrast to those which have not been degassed, polymerize rapidly even under room illumination. Freezing-point depression measurements fix a lower limit to the average molecular weight of the polymer at 2700 (n = 23 monomer units).
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    Determination of polymer branching with gel-permeation chromatography. I. TheoryPresented in part at the 4th, 5th and 6th International GPC Seminars: Miami Beach, 1967; London, 1968; Miami Beach, 1968. (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1361-1371 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of long-and short-chain branching in polymer molecules on gel-permeation chromatographic (GPC) separation is discussed. The calculation of calibration curves for branched polymers is developed from the universal calibration technique based on the hydrodynamic volume concept and previously established relationships for the effect of branching on molecular dimensions. Typical calibration curves are shown for different branching models and degrees of branching. As branching increases, the curves are shown to converge. Methods of characterizing branching and molecular weight distributions of franctions and whole polymers from GPC and intrinsic viscosity data are presented.
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    Determination of solubility coefficients from diffusion time lags (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1411-1412 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080812
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    Definition and proper usage of the various components in light scattering (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 2029-2032 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1970.160081115
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    Solution of Fujita's equation for equilibrium sedimentation by applying Tikhonov's regularizing functions (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 2039-2050 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Fujita equation relating molecular weight distribution to concentration of solution subjected to centrifugal forces in equilibrium proved to be an improperly posed problem in the Hadamard sense. Application of Tikhonov's regularizing functions leads to a good approximate solution of Fujita's equation. Such functions have been applied to a monomodal and a bimodal molecular weight distribution, and approximate results have been computed.
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    Superposition of dynamic mechanical properties in the glassy state (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1627-1634 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Superposition of the loss tangent curves could be achieved for the β-transition of a series of homologous epoxy resins. It was found that both a vertical and horizontal shift were necessary to achieve superposition when the curves were plotted as the logarithm of the loss tangent versus reciprocal absolute temperature. Resins from the diglycidyl ether of bisphenol A (DGEBA) were prepared with five different curing agents and their loss tangent curves measured on a free-oscillation torsion pendulum (ca. 1 cps). The β transition is caused by DGEBA, which was found via molecular models to contain a mobile group. The intensity of the loss for three of the resins was found to be proportional to the concentration of DGEBA, molecular models revealing that no additional mobile groups were introduced by these curatives. The remaining two curing agents introduced mobile groups into their systems and for these two, no separate transitions were identified but the intensity of the DGEBA β transition was increased. This may be caused by a coupling of the DGEBA mobile groups through the flexibility of the curative-introduced mobile groups.
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    Effect of temperature on the dynamic young's and shear moduli of unidirectional carbon fiber-epoxy composite beams (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1575-1584 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The resonance frequencies of unidirectional carbon fiber reinforced/epoxy composite beams were studied over the temperature range 24-225°C. Longitudinal Young's moduli E11 and longitudinal-transverse shear moduli G12 were computed from the experimental data by the use of Timoshenko beam theory. The effects of transverse shear deformation (a function of E11/G12) were found to increase in importance with increasing temperature. Values of G12 were found to be approximately proportional to the shear modulus Gm of matrix material but were about 30% lower than predicted by the theory of Hashin and Rosen. The anisotropy of the carbon filaments and voids in the composite samples were proposed to account for the discrepancy between theory and experiment.
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    Treatise on adhesion and adhesives, Volume I. Robert L. Patrick, Editor, Marcel Dekker, New York, 1967. $21.75 (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1635-1635 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080916
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