CARBOXYLIC ACIDS IN SYNTHETIC LUBRICANTS ON Guenter Spengler, K. A. Davis, R. Woerle et al Jan. 1974 Antiwear effectiveness investigations of carboxylic acids with N74-21080# European Space Research Organization, Paris SPECTROSCOPIC ANALYSIS OF WEAR METALS BASED Eilhard Jantzen Feb. 1974 53 p refs Transl. into ENGLISH (ESRO-TT-23; DLR-FB-73-06) Avail: NTIS HC $5.75 Tests were made using these spectroscopic methods on oil N74-21081# Army Construction Engineering Research Lab., Champaign, III. Kenneth W. Carlson Jan. 1974 18 p refs Many specifications for electromagnetically shielded facilities GRA N74-21082# Air Force Systems Command, Wright-Patterson THE PERFECTION OF FORGE AND PRESS PRODUCTION The book presents information about the state of the forging GRA N74-21083# Defense Documentation Center, Alexandria, Va. Areas in which ultrasonic energy can be effectively applied N74-21085# Naval Civil Engineering Lab., Port Hueneme, DEVELOPMENT OF A HYDRAZINE GAS-GENERATION K. W. Tate Dec. 1973 65 p refs (AD-774467; NCEL-TR-800) Avail: NTIS CSCL 13/10 The report describes the development and testing of a GRA N74-21086# New York Univ., N.Y. or = In section 1 a number of problems relating to the ratio (AD-774365; LO242) Avail: NTIS CSCL 13/7 Many claims have been made, some extravagantly, regarding fluidic system reliability. For the most part these claims have been substantiated qualitatively in many applications. However, in the past, quantitative methods have not been available to either predict reliability or to design accelerated failure experiments. The report describes work performed over a two year period with the purpose of developing an accelerated testing method and a method of predicting system life. (Modified author abstract) N74-21088# Nexon, Inc., Dayton, Ohio. GRA ASSESSMENT OF ULTRASONIC NDT INTERROGATION (AD-774046; AFML-TR-73-189) Avail: NTIS CSCL 14/2 The purpose is to evaluate the feasibility of detecting and characterizing small flaws (i.e. of the order of 1-100 microns) in materials by means of ultrasonic interrogation techniques. The scope of the effort encompasses an examination of the physical characteristics to be measured and their relation to the actual observable data obtained by measurement; an examination of the relation of measurement and perceptual theory to the specific measurement under consideration; the empirical evidence available for the feasibility of actually accomplishing the desired measurement; an analytic examination of the feasibility and appropriateness of the recommended technique that will have evolved from the above considerations; and finally, an overview of the current-state-of-measurements with relation to the instrumental requirements for the suggested approach. GRA N74-21089# Army Mobility Equipment Research and Development Center, Fort Belvoir, Va. PRESSURE-BOWL STRESS TESTS OF COATED FABRIC (AD-774292; USAMERDC-2081) Avail: NTIS CSCL 13/4 The report describes the setup, operation, and results of stress tests of coated fabric material and vent-flange attachments used in self-supporting, collapsible fuel storage tanks. Coated fabric material was exposed to fuel saturated with water and subjected to a fabric stress of 51.8 pounds per inch. These tests were used in conjunction with laboratory tests and field tests to determine the effect of various environments and fuels on coated fabric material. Material stressed in a pressure-bowl apparatus did not produce the wet-spotting previously observed in 5000-barrel, collapsible fuel storage tanks but did allow determination of nylon and coating deterioration in coated fabric of various construction. 16 MASERS Author (GRA) Includes applications of masers and lasers. For basic research see: 26 Physics, Solid-State. N74-21090 Tennessee Univ., Knoxville. AN INVESTIGATION OF THE INTERACTION OF LASER RADIATION WITH PLASMA ELECTRONS Ph.D. Thesis John Francis Seely 1973 91 p Avail: Univ. Microfilms Order No. 74-3866 The interaction of laser radiation with plasma electrons is investigated from quantum a mechanical viewpoint. The electromagnetic field of the laser beam is treated as a classical plane wave, and the plasma electrons are treated quantum mechanically. The absorption of laser radiation by multiphoton inverse Bremsstrahlung is considered. A kinetic equation is derived and the change in kinetic energy of the electrons is calculated. Effective collision frequencies are found for the two cases of weak field and strong field and are compared to the classical results. Finally, the solution to the Schrodinger equation for a particle in an electromagnetic wave and a parallel magnetic field is obtained. The production of positron-electron pairs in a laser beam is considered. Using the Volkov solutions to the Dirac equation, an expression for the cross section for pair production induced by the absorption of a gamma ray is derived. Dissert. Abstr. N74-21091* National Aeronautics and Space Administration. Goddard Space Flight Center, Greenbelt, Md. LONG RANGE LASER TRAVERSING SYSTEM Patent Louis O. Caudill, inventor (to NASA) Issued 16 Apr. 1974 6 p Filed 14 Jul. 1971 Supersedes N72-21503 (10 - 12. p 1621) (NASA-Case-GSC-11262-1; US-Patent-3,804,525; US-Patent-Appl-SN-162380; US-Patent-Class-356-152; The relative azimuth bearing between first and second spaced terrestrial points which may be obscured from each other by intervening terrain is measured by placing at one of the points a laser source for projecting a collimated beam upwardly in the vertical plane. The collimated laser beam is detected at the second point by positioning the optical axis of a receiving instrument for the laser beam in such a manner that the beam intercepts the optical axis. In response to the optical axis intercepting the beam, the beam is deflected into two different ray paths by a beam splitter having an apex located on the optical axis. The energy in the ray paths is detected by separate photoresponsive elements that drive logic networks for proving indications of: (1) the optical axis intercepting the beam; (2) the beam being on the left of the optical axis and (3) the beam being on the right side of the optical axis. Dissert. Abstr. N74-21092 California Univ., Los Angeles. Y.-C. Yeh 1973 121 p Avail: Univ. Microfilms Order No. 74-3990 A reactive Q-switched CO2 laser was studied both experimentally and theoretically. The theoretical analysis included the effects of the relaxation between various vibration-rotational states on the system. These effects were lumped into a 3-level and a 9-level model. The calculations were carried out using numerical techniques by means of an IBM 360-91 computer. The 9-level model was found to give much closer agreement with the experimental observations. It should be noted that the 9-level model does not have more arbitrarily adjustable parameters than the 3-level model. That is, all of the additional rate constants and time constants that appear in the 9-level model are known constants. The sensitivity of the 9-level model to various rates and time constants is also demonstrated. Dissert. Abstr. N74-21093 Oregon Univ., Eugene. Martin Charles Edelson 1973 157 p Avail: Univ. Microfilms Order No. 74-6823 The pulsed ruby laser was employed in the Q-switched mode in order to study multiphoton absorption in a variety of materials. This low probability event is only observable with sources of high photon flux, such as the Q-switched laser. The special precautions necessary in the two-photon absorption studies of liquids are discussed, and are applied to the study of liquid alpha-chloronapthalene. The two-photon absorption spectrum of Strontium Titanate (SrTiO3) is presented. The spectrum is analyzed in terms of band-to-band transitions and the two-photon band-gap energy is found to be ca. 3.8eV. A polarization study of the two-photon absorption at 4.00 eV is presented. An electronic optical spectrograph was constructed in order to obtain ultra-fast Raman spectra. This system utilizes the pulsed ruby laser as a highly monochromatic source of high radiance. A discussion is presented of the attempt to observe Raman scattering from the excited states of benzene and polyvinyl carbazole. Dissert. Abstr. N74-21094 State Univ. of New York, Stony Brook. Peter Karl Schenck 1973 114 p Avail: Univ. Microfilms Order No. 74-6746 The signal width of conventional level crossing experiments is limited by the natural width of the line. In order to reduce the signal width in our level crossing experiments, the observation of the resonance fluorescence is delayed after the excitation pulse provided by a pulsed tunable dye laser. The use of the dye laser excites enough atoms in a time short compared to the lifetime of the excited state, to allow the delay to be several lifetimes. The resonance fluorescence is then sampled for an interval short compared to the lifetime with a fast detector. The resulting signals are oscillatory in both magnetic field and the time delay. When the delay is several lifetimes the width of the level crossing signal is narrower than usually obtained in level crossing experiments employing continuous excitation and observation. These signals constitute time resolved level crossing signals. Dissert. Abstr. N74-21095 Illinois Univ., Urbana. Avail: Univ. Microfilms Order No. 74-5586 Gas lasers operating at discrete visible wavelengths were mode-locked to provide sources for pulsed excitation of various pigments in photosynthetic materials. The decay kinetics of in vivo molecular excited state populations produced by these sources were studied using both conventional and newly developed high time resolution fluorometric techniques. By choosing laser wavelengths which could selectively excite either chlorophyll a (Chl a) or an accessory pigment which could nonradiatively transfer its energy to Chi a, the time characteristics of energy migration between the two pigments are investigated. Dissert. Abstr. N74-21096# Institut Franco-Allemand de Recherches, St. Louis (France). INVESTIGATION OF HYPERSONIC FLIGHT PROJECTILES AND WAKES USING HOLOGRAPHIC METHODS Ph.D. Thesis Besancon Univ., France [ETUDE DES PROJECTILES EN VOL HYPERSONIQUE ET DE LEURS SILLAGES PAR DES METHODES HOLOGRAPHIQUES] Paul Smigielski 10 Oct. 1973 252 p refs In FRENCH; ENGLISH summary Sponsored by Direc. des Rech. et Moyens d'Essais (ISL-24/73) Avail: NTIS HC $15.75 General considerations and basic principles concerning techniques used in the field of high-speed holography are dealt with including: advantage of high-speed photography in ballistic ranges over other, more conventional methods used so far; and influence of the object motion as well as of geometrical aberrations on the reconstructed image in realistic cases (uniform linear motion, changes occurring in the wavelength between hologram recording and image reconstruction, strong angular variations between reference beam, object beam, and normal to the hologram). The techniques used are described. Methods of visualizing wakes of projectiles were investigated. The wave reconstructed with the aid of holography was successively analyzed using differential interferometry in polarized light, schlieren techniques including a phase plate that is defocused with respect to the Fourier plane, and holographic interferometry with double exposure in directional light as well as diffused light. The theoretical and experimental results achieved in using the above mentioned methods in the ballistic range such as visualization of wakes and observation of the surface of hypersonic projectiles are presented. Author (ESRO) N74-21097# Institut Franco-Allemand de Recherches, St. Louis (France). QUALIFICATION OF FREEZING FOGS BY HOLOGRAPHY [QUALIFICATION DES BROUILLARDS GIVRANTS PAR HOLOGRAPHIE] H. Royer 13 Sep. 1973 25 p In FRENCH (Contract CEPR-72-0126) (ISL-25/73) Avail: NTIS HC $4.25 Holographic data were recorded and processed under various conditions to develop a holographic method for the qualification of freezing fogs. It is shown that using a few fog injector numbers, the quality of images obtained was satisfactory even for the high water flow. In addition, the development of an electronic lens for the restitution system reduced the image data processing time in a 1/3 factor. ESRO N74-21098# Institut Franco-Allemand de Recherches. St. Louis (France). EXPERIMENTAL INVESTIGATION OF THE STIMULATED EMISSION IN THE ELECTRON BEAM EXCITED NITROGEN [ETUDE EXPERIMENTALE DE L'EMISSION STIMULEE DANS L'AZOTE EXCITE PAR FAISCEAU D'ELECTRONS] F. Jamet and A. Hirth 8 Nov. 1973 19 p refs In FRENCH (ISL-29/73) Avail: NTIS HC $4.00 A 750 kV (100 J) Marx generator connected to a discharge tube was used as an electron gun. The results of a parametric study of super radiant laser action at 337 nm in the second positive band system of molecular nitrogen with excitation by a 1300 A electron beam are reported. Laser output power up to 1 MW in a 2 nsec pulse was observed. In addition, tabulated data on nitrogen laser emission characteristics obtained by various authors using various electron guns are given. ESRO N74-21099# Max-Planck-Institut fuer Physik und Astrophysik, Munich (West Germany). Inst. fuer Extraterrestrische Physik. ENERGY DISTRIBUTION OF THE REACTIVE DISPERSION OF Ba AND Ba2 WITH OXYGEN (DIE ENERGIEVERTEILUNG DER REAKTIVEN STREUUNG VON Ba AND Ba2 MIT SAUERSTOFF] Andreas Plagge Oct. 1973 140 p refs In GERMAN (MPI-PAE-Extraterr-89) Avail: NTIS HC $10.00 The possibility of wave excited barium oxide forming a laser system was investigated theoretically. The energy distribution of the barium oxide formed was estimated as a function of the wave frequency. The Einstein coefficient for the spontaneous emission was calculated, and the amplification ratio was computed using the Ben-Shaul theory. The theory was tested in a suitable ESRO molecular beam apparatus. N74-21100# Naval Ordnance Lab., White Oak, Md. Jerry Wagner 11 Oct. 1973 40 p refs Experimental results for the temperature dependence of the 10.6 micrometer absorption coefficient of SF6-air mixtures are presented. A summary from previous works is also presented which provides complete variations of absorption coefficient with pressure, wavelength, and temperature. This fundamental physical data provides insight into the understanding of laser radiation absorption mechanisms in SF6-air mixtures. Author (GRA) N74-21101# Maryland Univ., College Park. Dept. of Aerospace Engineering. SENSITIVITY OF GASDYNAMIC LASER CALCULATIONS TO UNCERTAINTIES IN KINETIC RATES John D. Anderson, Jr. Oct. 1973 57 p refs (Grant AF-AFOSR-2575-74; AF Proj. 9750) (AD-774135; AFOSR-74-0134TR; AEA73-2) Avail: NTIS CSCL 07/4 Recent data for the vibrational energy exchange rates associated with CO2-N2-H20 gas lasers is compared with previous compilatons. From this, current uncertainties in the rate data are established. Using an existing computer code, a study is made of the sensitivity of gasdynamic laser performance to these uncertainties. The results show that present-day calculations of gasdynamic laser gain and maximum available power are subject to at least a 25% inaccuracy due to such rate data uncertainties. Author (GRA) N74-21102# Naval Research Lab.. Washington, D.C. STRIPLINE POCKEL'S CELL ASSEMBLY INSTRUCTIONS Jules P. Letellier Jan. 1974 13 pref (ARPA Order 2062; NRL Proj. K03-08A) (AD-774495; NRL-MR-2716) Avail: NTIS CSCL 20/5 The report contains a step-by-step assembly procedure for the Pockel's cells used in the NRL Glass Laser Facility. Also included are some repair notes. Author (GRA) N74-21103# Air Force Inst. of Tech., Wright-Patterson AFB. Ohio. School of Engineering. Schlieren photographs were used to analyze the flow characteristics of diffusers for a Mach 6.0 double nozzle assembly. This assembly of two nozzles, comprised of one (1) full center and two (2) half side channels, was more conducive to greater boundary layer growth than a nozzle assembly with more nozzle throats. Schlieren photographs of the air flow were in line with the laser beam's orientation to the nozzles of a Gas Dynamic Laser. Dry air at 85 F total temperature, and 120 psia total pressure was expanded with a nozzle area ratio of 66.0. Different diffuser configurations were tried to determine the diffuser throat area required to start the cavity. It was determined that the cavity would start when the ratio of diffuser throat area to channel cross-sectional area was near 0.6, which is in agreement with other studies, considering the presence of wakes in the flow. Boundary layer growth is accelerated at these high Mach numbers, limiting the distance between the nozzles and diffuser; excellent optical charity flow was obtained emerging from the nozzles and close to the channel center using a multi-element diffuser, but, deteriorates rapidly further downstream. Author (GRA) N74-21104# Aerospace Corp., El Segundo, Calif. Aerophysics Lab. ELECTRON BEAM IRRADIATED DISCHARGES CONSIDERED FOR INITIATING HIGH-PRESSURE PULSED CHEMICAL LASERS Report for Dec. 1972 - Apr. 1973 Robert Hofland, Martin L. Lundquist, Alfred Ching, and James S. Whittier 31 Oct. 1973 59 p refs (Contract F04701-73-C-0074) (AD-774095; TR-0074(9240-05)-1; SAMSO-TR-74-16) Avail: NTIS CSCL 20/5 Volumetric irradiation by a short-pulse electron beam has been used to trigger long-duration, spatially uniform electric discharges in gas mixtures of He and F2 or SF6. Uniform energy deposition to 300 J/liter has been observed for atmospheric F2-He mixtures at nominal e-beam currents of 3 A/sq cm and discharge currents up to 20 A/sq cm. Operation suitable for efficient initiation of pulsed HF/DF chain lasers appears possible over a wide range of E/N and mixture ratios, limited by breakdown at large E/N and negligible field enhancement at low E/N. Approximate analytical plasma models are presented and used in conjunction with time-resolved afterglow current measurements to obtain rate constants for F- ion-F2 ion recombination and F2- ion-electron recombination. Estimates of F2 dissociation fractions achieved in the experiments imply the possibility of scalable and efficient initiation of pulsed chemical lasers with such discharges. Author (GRA) The program is an investigation of the feasibility of using holographic interferometry for the inspection of large aircraft structures in a manufacturing or maintenance environment. The second year's work comprised the following: an investigation of the effects of airborne particulates on the holographic process, a study of holographic methods suitable for the manufacturing or maintenance environment, an investigation and experimental demonstration of two new moire methods for the visualization of strain patterns, investigations of potential stress generating mechanisms, suitable for the holographic detection of cracks, in which it was experimentally demonstrated that surface waves can be generated and attenuated by cracks, and experimental demonstrations that illustrated the potential of holography, in combination with ultrasonic excitation, for solving cooling passage alignment inspection problems. (Modified author abstract) GRA N74-21106# General Electric Co., Schenectady, N.Y. THREE DIMENSIONAL DIAGNOSTIC TECHNIQUES - J. C. F. Wang and J. A. Asher Dec. 1973 58 p refs The report describes a study of 3-D diagnostic techniques for measurements of flow velocity in the test section of a hypersonic wind tunnel. A successful on-site demonstration using a laser velocimeter system is discussed in detail. The close agreement between the LV and theoretical results demonstrates the feasibility of employing this technique in supersonic or hypersonic flow situations. Some technical experiences and considerations concerning the LV system as well as a few improvements for further development are also reported. (Modified author abstract) GRA N74-21107# Texas Instruments, Inc., Dallas. Central Research Labs. CHALCOGENIDE GLASSES FOR HIGH ENERGY LASER APPLICATIONS A. R. Hilton, D. J. Hayes, and M. D. Rechtin Jan. 1974 67 p refs (Contract NO0014-73-C-0367; ARPA Order 2443) Substantial reduction in the absorption at 10.6 micrometers is required before chalcogenide glasses can be used with high-energy CO2 lasers. In this program, new methods for compounding high-purity TI-1173 glass (composition Ge28Sb12Se60) and TI-20 glass (composition Ge33As12Se55) were developed. At the present stage of purity, the absorption for TI-1173 at 10.6 micrometers is about 0.01/cm. The absorption is dominated by the silica content of the glass and can be lowered if the impurity is removed. The absorption for TI-20, however, is presently about 0.05/cm and is dominated by a broad, low-level absorption centered about 12.8 micrometers. The absorption appears to be intrinsic, and little can be done to improve TI-20 further. (Modified author abstract) GRA (AD-774701; SAR-3) Avail: NTIS CSCL 20/5 The goal of this program is to reduce the absorption, and improve the mechanical properties, of alkali halides for laser window use. During this reporting period, a number of important results in infrared absorption have been achieved: (1) Nearly intrinsic bulk absorption has been found at 10.6 micrometers in chemically polished KCI crystals which were grown in a reactive atmosphere; (2) Intrinsic and extrinsic absorption in KCI has been distinguished by studies of its temperature dependence; (3) A 9.8 micrometers surface impurity band in KCI has been detected by laser calorimetry; and, (4) Frequency and temperature dependence of absorption at wavelengths 10.6 micrometers has been studied with the spectral emittance studies at NELC. GRA N74-21109# Purdue Univ., Lafayette, Ind. School of Mechanical Engineering. THE DESIGN OF A LASER DOPPLER VELOCIMETER FOR TRANSONIC FLOWS Interim Report, 26 Aug. 1971-30 Jun. 1973 Michael K. Pedigo and Warren H. Stevenson 29 Oct. 1973 99 prefs (Contract DAAH01-72-C-0089; DA Proj. 1M2-62303-A-214) (AD-774302; RD-73-25) Avail: NTIS CSCL 20/4 Design considerations for laser Doppler velocimeters suitable for transonic flow measurements are presented. The optical and mechanical elements of an instrument designed for such application are described in detail. The device is of the differential Doppler-backscatter configuration and uses an argon laser. Independent and simultaneous measurement of two orthogonal velocity components is accomplished by using both the 4880 and 5145 angstrom argon wavelengths. Results of preliminary velocity measurements in a two-dimensional transonic INVESTIGATION OF HIGH POWER MHD GAS LASERS Annual Report, 1 Jan. 31 Dec. 1973 Bert Zauderer, Eric Tate, and C. H. Marston 31 Dec. 1973 52 p refs Sponsored in part by ARPA (Contract NO0014-73-C-0243) (AD-773975) Avail: NTIS CSCL 20/5 The primary objective of this year's effort, the achievement of optical gain in an MHD channel, has been met. Gain of 0.2%/cm at 10.6 micrometers has been repeatedly measured in two gas mixtures He/Ne/ CO2/Xe and He/Ar/CO2/Cs. GRA 17 MATERIALS, METALLIC Includes cermets; corrosion; physical and mechanical properties of materials; metallurgy; and applications as structural materials. For basic research see: 06 Chemistry. For related information see also: 18 Materials, Nonmetallic; and 32 Structural Mechanics. N74-21111 Case Western Reserve Univ., Cleveland, Ohio. Avail: Univ. Microfilms Order No. 74-2574 The orientation dependence of both the yield stress and slip systems of pure tantalum and tantalum alloys containing up to approximately 500 atomic ppm nitrogen was investigated at 77 K and 197 K. Oriented single crystals were grown in a zone melter, and purified using a UHV solid state outgassing technique. Specimens with orientations -30 is less than or equal chi is less than or equal +30 were tested in tension and compression; slip trace analysis was done on many of the specimens. At 77 K, the yield stress is a minimum when chi -30, and for any orientation, the yield stress in compression is greater than the yield stress in tension. At 197 K, for an orientation with chi = +30, the strength differential between tension and compression reversed, and the yield stress in tension was greater than the yield stress in compression. The rate of alloy hardening was found to be a strong function of orientation, nitrogen content, and also mode of testing (tension or compression). N74-21112 Michigan Univ., Ann Arbor. = Dissert. Abstr. MASS AND HEAT TRANSFER DURING DISSOLUTION OF Avail: Univ. Microfilms Order No. 74-3656 The rates of dissolution of a solid pure iron and a solid iron-carbon alloy into molten iron-carbon alloys were studied isothermally as a function of temperature, carbon content and ferrodynamic (stirring) conditions. Experiments were carried out in a resistance-heated tube furnace under an inert atmosphere of argon gas at temperatures ranging from 2165 F to 2563 F. A cylindrical specimen of the solid was preheated to the liquid temperature and immersed into the liquid bath contained in a graphite or alumina crucible at rotational speeds ranging from O to 1800 rpm. The dissolution rate was shown to be mass transfer controlled. The mass transfer coefficients were calculated with the assumptions that the reaction of phase transformation at the solid-liquid interface was fast enough to maintain the equilibrium compositions at the solid temperature with an appropriate heat supply from the bulk liquid for the latent heat of phase transformation, and that the dissolution rate was controlled by diffusion in a boundary layer and the bulk liquid was maintained at a uniform composition by convective motion in the liquid. Dissert. Abstr. N74-21113 Illinois Univ., Urbana. THE PHASE TRANSITION OF A COBALT-NICKEL ALLOY Ph.D. Thesis William Francis Weston 1973 92 p Avail: Univ. Microfilms Order No. 74-5732 A cubic single crystal of cobalt-31% nickel was transformed to a hexagonal single crystal. The univariant transformation was accomplished by prestressing a cubic crystal until single slip was observed and cooling to liquid nitrogen temperature. Evidence that the transformed specimen was a hexagonal single crysta was obtained from Laue X-ray photographs, surface markings analysis of the magnitude of sound wave velocities and the symmetry of their polarizations, and the magnetic field dependence of the attenuation of certain modes. Complete sets of secondand third-order elastic constants (except for C13) of both phases were determined experimentally from measurements of the natural sound velocities and hydrostatic pressure and uniaxial compression stress derivatives of the natural sound velocities. A gated pulse superposition technique was used. The C13 could not be determined experimentally because of the orientations of the hexagonal crystal. A procedure based on a simple rotation of the cubic constants was used to estimate C13. Dissert. Abstr N74-21114 Brown Univ., Providence, R.I. Harvey Lewis Kaufman 1973 130 p Observations of the enhanced diamagnetism in bulk, cylindrical single crystals of pure aluminum and its alloys are reported The impurity in all cases is silver. The diamagnetism occurs above the thermodynamic normal-superconductor transition temperature and is attributed to the formation of an appreciable number of Cooper pairs by means of fluctuations in the superconducting order parameter. Anomalous surface effects were also present in a number of dirty alloys. This effect is represented by a diamagnetic magnetization well in excess, by at least an order of magnitude, of that expected from the bulk fluctuations alone. It was found, however, that upon careful electropolishing of the surface and subsequent electroplating of a normal metal onto the alloy, the broadening was reduced to the extent that the bulk fluctuation magnetization was clearly observable. Dissert. Abstr N74-21115 Illinois Univ., Urbana. A STUDY OF METAL-OXYGEN SOLID SOLUTIONS UTILIZ- A thermodynamic study was made of the niobium-oxygen, tantalum-oxygen, niobium-oxygen-nitrogen, and tantalum-oxygennitrogen systems utilizing the solid state galvanic cell technique. Investigations were made over the temperature range 850 to 1275 C in a pressure range of low 10 to the 7th power to 10 to the 8th power torr utilizing a ThO2/Y203 electrolyte Some preliminary results for the activation energy for diffusion of oxygen in nickel and niobium are reported. The terminal solubility of oxygen in niobium and tantalum are determined Ternary nitrogen additions up to about 1.5 at.% are found to have little effect on the oxygen terminal solubility and related thermodynamics. It is concluded that oxygen obeys Henry's law for the temperatures of this investigation for concentrations up to the terminal solubility. No significant clustering or interactions between interstitial solute atoms are detected in either the binary or ternary systems. Dissert. Abstr. |