Selected Abstracts

Blaine, R. L., Tomes, L. A., Exploratory studies of early strength development in portland cement pastes and morars, Nat. Bur. Stand. (U.S.), Bldg. Sci. Ser. 28, 14 pages (July 1970) 15 cents, SD Catalog No. C13.29/2:28.

Key words: Cement: cement mortar: cement paste; early strength; alse set; hardening of cement; hydration; shear resistance; theory of cement hardening: time of set; vane-shear apparatus.

modified vane-shear apparatus was used to measure the shear reistance of neat cement pastes of normal consistency and 1:2.75 cement to sand) mortars of standard consistency, and to measure he increase in shear resistance with time as the cements hardened. The hardening process appeared to occur in three stages. The rate f increase of shear resistance as well as the duration of the different hases differed with the different cements. The results were analyzed terms of the various theories proposed to explain the hardening of

ements.

Brauer, G. M., Pyrolysis-gas chromatographic techniques for olymer identification, Chapter 2. Thermal Characteristics echniques in Techniques and Methods of Polymer Evaluaons, P. Slade, Ed., II, 41-105 (Marcel Dekker Publ. New York, Y.. 1970).

ey words: Chromatographic analysis of degradation products; olymer characterization; polymer identification; pyrolysis-gas hromatography of polymers; pyrolytic techniques.

yrolytic techniques used in conjunction with gas chromatography e very useful for elucidating the structure of macromolecules. These methods are a powerful tool in the qualitative characterizaon of the gross structure, the study of the thermal stability of polyers and the identification of their pyrolysis products, but have also und an increasing number of applications for the quantitative nalysis of copolymeric systems and in studies of the kinetics of olymer degradation. The shape of the pyrograms is dependent on ne structural characteristics such as the degree of branching or rosslinking, stereoregularity, crystallinity and monomer sequence ength distribution in block and graft copolymers. Thus the pyrolysisas chromatographic technique opens up new avenues in studying he ultimate arrangement of monomeric units within the polymer hain.

Tyson, J. O., Carpenter, E. F., Flexural behavior of prestressed oncrete coniposite Tee-beams, Nat. Bur. Stand. (U.S.), Bldg. i. Ser. 31, 14 pages (July 1970) 25 cents, SD Catalog No. C13.29/ 31. Catalog of standard reference materials, Nat. Bur. Stand. .S.). Spec. Pub. 260-1970 ed., 84 pages (July 1970) 75 cents, SD atalog No. C13.10:260–1970 ed.

ey words: Composite concrete construction: prestressed concrete eams; Tee-beams.

restressed Tee-beams constructed by the split-beam method were sted to failure in flexure to study the behavior and ultimate strength E these beams and to compare their flexural characteristics with ith those of prestressed beams of conventional construction. The mpressive portion of the cross section of the split-beam is cast ter the web of the beam has been formed and prestressed. The ariables in the study included the percentage of prestressing eel, strength of concrete in the compressive element of the com

posite split-beams, manner of prestressing and web reinforcement. Results showed that the composite split-beams behaved similarly to the monolithically constructed beams on the basis of flexural response and ultimate load. The strength of the concrete for the compressive element can be reduced within limits from that required for the prestressed element without sacrificing ultimate load capacity. The required percentage of reinforcing steel is less for the split-beam compared with conventional beams.

Diller, D. E., Roder. H. M., Thermal conductivity measurements on fluid hydrogen at 17 to 200 °K and pressures to 10 MN m2 (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles, Calif.), Chapter in Advances in Cryogenic Engineering 15, Paper No. C-1, 58-64 (Plenum Press, Inc., New York, N.Y., 1970).

Key words: Critical region; parahydrogen; thermal conductivity. New absolute thermal conductivity measurements on fluid normal and parahydrogen are reported. A nominal accuracy of 2% has been achieved using a parallel plate apparatus in the temperature range 17 to 200 K at pressures to 100 atm and densities to 2.6 times critical. A graphical presentation of the data is given along isotherms, isochores, and isobars in the following regions: 1) the dilute gas. 2) the moderately dense gas, 3) the saturated and compressed liquid, 4) the critical region. Several interesting features of the behavior of the thermal conductivity of this fluid are pointed out: 1) the thermal conductivity of saturated liquid hydrogen increases with temperature between the triple point and the normal boiling point in contrast to the temperature dependence for most liquids other than helium. 2) a large anomalous increase in the thermal conductivity of hydrogen was found in the vicinity of the critical point.

Gonano, R., Adams, E. D., In Situ vapor pressure measurement for low temperature thermometry, Rev. Sci. Instr. 41, No. 5. 716-719 (May 1970).

Key words: Capacitance manometer; cryogenic thermometry; manometry: pressure measurement; thermomolecular pressure difference; vapor pressure.

By use of a capacitance diaphragm manometer operated at cryogenic temperature, it is possible to measure the vapor pressure of cryogenic liquids without the uncertainties introduced by thermomolecu lar pressure gradients (thermal transpiration). Since the zero of this manometer is more stable at low temperature than at room temperature, useful sensitivity is also increased. Because of the increased accuracy at low pressure as well as great convenience and simplicity. this technique appears to have wide application in precise vapor pressure thermometry and similar work.

Hamilton. W. C.. Edmonds. J. W., Tippe, A., Rush, J. J., Methyl group rotation and the low temperature transition in hexamethylbenzene. A neutron diffraction study, Discussions Faraday Soc., No. 48, 192-204 (1969).

Key words: Barrier to rotation: crystal; crystal structure; hexamethylbenzene; hindered rotation: phase transition; point methyl group; torsional oscillation.

Neutron diffraction studies of single crystals of hexamethylbenzene at 298 K and at 130° K indicate that the molecule in Phase II has approximate D3a symmetry. The amplitudes of libration of the methyl

group and of rigid body motions of the molecule are consistent with earlier data, except that the barrier to methyl group rotation appears to be somewhat lower-in the neighborhood of 2000 J/mol. Consideration of intra- and inter-molecular hydrogen atom contact distances and calculated potential energy curves using a 6-exp potential function suggest that intermolecular forces are important in determining the barrier to rotation of the methyl groups and that substantial changes in the intermolecular packing must be responsible for the lambda-point transition at 116° K and the consequent profound change in the potential barrier to internal rotation which has been previously observed.

Heinrich, K. F. J., Present state of the classical theory of quantitative electron probe microanalysis, Nat. Bur. Stand. (U.S.), Tech. Note 521, 17 pages (Aug. 1970) 30 cents, SD Catalog No C13.46:521.

Key words: Corrections; electron probe microanalysis; quantitative analysis: x-ray spectroscopy.

Although the foundations for a procedure of data reduction in quantitative electron probe analysis have not been changed for several years, there has been progress in the choice of expressions, parameters, and constants. A brief account of recommended expressions and procedures is given. Reference is made to the Standard Reference Materials of Au-Ag and Au-Cu alloys issued for electron probe microanalysis. These are especially useful for investigating the application of correction procedures.

Madey, T. E., Yates. J. T., Jr., Chemisorption on single crystals: H2 on (100) tungsten, Proc. Colloque Intern. sur la Structure et les Proprietes des Surfaces des Solides, Paris, France, July 7-11, 1969, No. 187, pp. 155-162 (Centre National de la Recherche Scientifique, Paris, France, 1970).

Key words: Binding state; chemisorption; hydrogen; isotopes; single crystal; tungsten; work function.

An ultrahigh vacuum apparatus has been constructed to study flash desorption of gaseous molecules from macroscopic single crystals. The crystals are in the form of thin discs, polished on both faces. whose total surface area is 95 percent of one orientation. A focussed light source external to the vacuum system is used to heat the nearly adiabatically suspended sample to 7 > 1200 K; temperature inhomogeneities and end effects which complicate kinetic measurements on resistively heated samples are not present here. The sample is cleaned by electron bombardment prior to making adsorption measurements. Work function changes upon adsorption are monitored using an electron gun; a quadrupole mass spectrometer is used as the detector of desorbed species.

The chemisorption of H. and D. on a (100) oriented tungsten disc has been examined with this apparatus. The hydrogen desorption spectra reveal that two binding states exist on the (100) surface. The first order B, state desorbs with an activation energy of ~ 25 kcal/mole and at saturation coverage, is twice as densely populated as the B state. The coadsorption of an equimolar mixture of H. and D. shows that both states are isotopically mixed upon desorption. The work function-coverage relation is linear over the entire coverage range; the dipole moment per atom is 0.15 Debye, independent of binding state. Several models of H2 chemisorption are discussed.

Pfeiffer, E. R., Schooley, J. F., Effect of stress on the superconducting transition temperature of SrTiO3, J. Low Temp. Phys. 2, No. 3/4, 333–352 (August 7, 1970).

Key words: Anisotropic stress effect; hydrostatic pressure Nbdoped SrTiO3: 0-1.8 kbars; reduced SrTiO3; superconductivity: transition temperatures; uniaxial compression.

The superconducting transition temperatures of several specimens of reduced SrTiO, and of Nb-doped SrTiO; have been investigated as functions of hydrostatic and uniaxial compressive stresses up to 1.8 kbars. Large decreases in Te were observed in each specimen under hydrostatic pressure. Because of the low Te and small compressibility of SrTiO3, A(ln To)/AP and A(In T.)/A(ln V) are orders of magnitude greater than the corresponding effects in the elemental

superconductors. An anisotropic uniaxial stress effect was observed [111] compression caused large decreases in Te, while both smal increases and small decreases in Te were observed for specimen under [100] compression. It is believed that the present result reveal a sensitive volume dependence of one or more of the param eters important to superconductivity in SrTiO3, and that no sig nificant electron-transfer effects occurred in the range of stresse of this experiment.

Rockett, J. A., Objectives and pitfalls in the simulation o building fires with a computer, Fire Tech. 5, No. 4, 311-32 (November 1969).

Key words: Building; computer; fire; simulation.

The complex interactions between a building and a fire are bein studied using the NBS computer facility. A description of the build ing in a form suitable for use with the computer has been developed Obtaining sufficient detail in the description to allow a good repre sentation of the building, with an easily manageable amount of inpu data, has been a major problem. In describing the fire, it is necessar to determine the a movements induced by the fire, since thes establish both the severity and extent of the fire, and the movemen of smoke and toxic products. The technical problem is twofold not enough is known about convective air movements and how t calculate them, and those calculations which can be carried out ar excessively time consuming. Concurrently, information is lackin on the precise configuration of the building at the time of the fire which doors are open or closed and where critical items are located By highlighting the information needs for a successful calculation the fire simulation study provides a guide to future research. Insofa as the study is able to represent correctly actual building fires. provides a useful tool to the fire protection engineer.

Searles, S. K., Sieck, L. W., High pressure photoionization mass spectrometry, III. Reactions of NO+(X'Σ†) with C1-C hydrocarbons at thermal kinetic energies, J. Chem. Phys. 53 No. 2, 794-797 (July 15, 1970).

Key words: Alkanes; excited states; ion-molecule reactions: mass spectrometry; photoionization; rate constants.

The vapor phase reaction of NO+(X'Σ+) with C3 through C, normal branched, or cyclic alkanes was found to proceed exclusively vi an H transfer mechanism:

NO (X'Σ+)+ RH2 − RH+ + HNO

In addition to (I), C4H was also formed by a second order process in the reaction with 3-methylhexane. Absolute rate constants were determined for all systems at thermal kinetic energies. Isomers containing tertiary H atoms were found to be the most reactive exhibiting rate constants on the order of 10-9 cm3/molecule-second Isotopic labeling has verified that only the tertiary site is involved in the H transfer reaction in those molecules having both secondary and tertiary H atoms. The rate constants found for n-alkanes and non-substituted cycloalkanes fall in the range 10-12 to 10-10 cm molecule-second. The bimolecular reaction cyclo-C6H1+NC -CHINO was also noted at higher pressures. No further reaction of the RH+ species generated in (I) was found in any other RH2-NC combination at pressures up to 0.5 torr.

Shinyayev, A. Y., Butrymowicz, D. B., Interdiffusion in and the phase diagram for vanadium-rich alloys of the V-Al systen at pressures 0 to 47 kbar, Met. Trans. 1, No. 7, 1905-190 (July 1970) Simson, B. G., Mandel, J., Brenner, F. C., Research to a uniform quality grading system for tires. III, Breaking energ Rubber Chem. and Tech. 43, No. 2, 356-369 (March 1970).

Key words: Alloys; aluminum; diffusion; high-pressure; phase diagram; vanadium.

The V-A system between 16 and 39 at. pct. Al was studied a 1400 °C under pressures of 0, 30, and 47 kbar. Electron micro probe analysis, x-ray diffraction, microhardness readings, an metallographic examination revealed only a single solid solution

Interdiffusion coefficients were determined as a function of composi tion and pressure. Concentration gradients were measured with an electron microprobe analyzer and the diffusion coefficients were calculated by the Matano analysis. At 1400 °C, the value of the interdiffusion coefficient varies from 1 to 12 × 10-9 cm2/s, increasing with aluminum content and decreasing with increasing pressure.

Straty, G. D., Prydz. R., The vapor pressure of liquid fluorine, (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles, Calif.), Chapter in Advances in Cryogenic Engineering 15, Paper No. B-1, 36–41 (Plenum Press, Inc., New York, V.Y., 1970).

Key words: Critical point pressure; fluorine; normal boiling point; vapor pressure data; vapor pressure equation.

This paper reports new vapor pressure measurements on liquid fluorine from the triple point to the critical point at 1 K intervals. Accuracies in both temperature and pressure approach a few hundredths of a percent. The data were fitted to a newly developed, non-analytic vapor pressure equation and compared graphically to earlier, inconsistent measurements available in the literature. Of this earlier data, the estimated P-T values above the normal boiling point and the value given for the critical pressure are in error by as much as 10 to 15 percent.

Sugar, J., Spectrum of doubly ionized thulium (Tm 11), J. Opt. Soc. Am. 69, No. 4, 454–466 (April 1970).

Key words: Doubly ionized thulium; energy levels of Tm III; radial energy integrals of Tm III; spectrum of Tm III.

A list of 848 low excitation spectral lines of Tm III has been obtained by utilizing the sliding spark light source at a peak current of 6 A. An analysis of these lines yielded 108 energy levels belonging to the configurations 4f3, 4f25d, 4f6s, and 4f6p. The classified lines and level values are presented as well as a theoretical interpretation of these configurations.

Tighe, N. J., Hockey, B. J., Ion thinning of electron microscope specimens (Proc. 10th Symp. Electron, Ion and Laser Beam Tech., May 21 23, 1969, National Bureau of Standards, Gaithersburg, Md., Record of 10th Symposium on Electron, Ion, and Laser Beam Technology, L. Marton, Ed., pp. 375–380 (San Francisco Press Inc., San Francisco, Calif., 1970).

Key words: ALO3; argon ion bombardment; ceramics; electron microscopy: hardness; ion thinning; SiO..

In recent years, it has been possible to prepare ceramic specimens for transmission electron microscopy using ion bombardment for thinning bulk samples to less than 0.5μm thickness. Chemical inertness and electrical insulating properties of many ceramic materials make chemical and electrochemical methods, such as those used for metals, difficult to apply. Even when suitable chemical polishes are found they often are useful only for certain crystallographeric orientations and not at all useful for polycrystalline bodies. In this laboratory, the ion-thinning technique has been applied to polycrystalline and single-crystalline ceramics including alumina. magnesia, silica and zirconia.

Prior to ion thinning, disk specimens 2.3 or 3 mm in diameter are cut from thin slices (40 to 150 μm) of the selected samples. When a specimen is particularly fragile because of large deformation, fractures, or porosity, a supporting rim is cemented to it. Specimens are thinned simultaneously from both sides and are rotated during thinning to eliminate or reduce directional grooving. They are thinned with argon ion beams using accelerating voltages of 4 to 8 kV and beam currents of 50 to 150μA. Thinning rates vary from 1/2 to lμm/hr depending on the specimen material and on the operating conditions.

The ion-thinned specimens have electron transparent regions which usually are more extensive than those in the best chemically thinned single crystal specimens. Studies of the microstructure of hotpressed alumina, periclase brick, quartz and magnetite rocks and a number of sintered ceramics have been undertaken. The dislocation

substructure, impurity precipitates, second phase grains, and voids have been revealed by transmission electron microscopy; and, in some cases, the defects have been related to the deformation sustained by specimens during forming or during mechanical testing. Because specimens can be thinned from only one side, it has been possible to study the damage in single and polycrystalline alumina specimens which is produced by hardness indents and by mechanical polishing with diamond abrasives.

Torrance, K. E., Orloff, L., Rockett, J. A., Numerical study of natural convection in an enclosure with localized heating from below-creeping flow to the onset of laminar instability, J. Fluid Mech. 36, Part 1, 33-54 (June 1969).

Key words: Circular cylinder; enclosures; natural convection; numerical.

An analytical study was made of the natural convection induced in an enclosure by a small hot spot centrally located on the floor. The enclosure was a circular cylinder, vertically oriented, with height equal to radius. A Prandtl number of 0.7 (air) was assumed; the Grashof number (Gr) was based on cylinder height and hot spot temperature. The equations of fluid flow in axisymmetric cylindrical coordinates were simplified with the Boussinesq approximation. The equations were solved numerically with a computationally stable, explicit method. The computation, starting from quiescent conditions, proceeded through the initial transient to the fully developed flow. Solutions were obtained for Gr from 4 × 10' to 4 × 101. The calculated flows were compared with the experimental flows presented in a companion paper, Torrance, Orloff and Rockett (1968). The experimental flows were laminar for Cr ≤ 1.2 × 10": turbulence was observed above this value. In the laminar flow region (Gr≤ 1.2 × 109) agreement between the theoretical and experi mental flow patterns was excellent. When extended into the experimentally observed turbulent range (Gr= 4 × 101) the theoretical flow developed a periodic vortex shedding, suggestive of the onset of transition.

Verdier, P. H., Relaxation behavior of the freely jointed chain, J. Chem. Phys. 52, No. 11, 5512–5517 (June 1, 1970).

Key words: Chain dynamics; polymers; random walk; relaxation; stochastic process.

A method is presented for treating the relaxation behavior of the freely jointed chain model of a random coil polymer. Exact results are exhibited for the relaxation of quantities linear in chain coordinates. For the treatment of quantities quadratic in chain coordinates, a numerical approach is employed and exemplified by obtaining the autocorrelation in the square of end-to-end length for chains of up to 16 beads. In both cases, the rapid approach of the behavior of the freely jointed chain of N beads to that of the Rouse model of V statistical segments is demonstrated.

Winogradoff, N. N., Neill, A. H., Jr., Temperature dependence of the power output of the spontaneous emission from GaAs laser diodes, Intern. J. Electron. 28, No. 5, 401–406 (1970).

Key words: Band tailing: GaAs lasers; non-radiative recombination centers; radiative recombination; temperature dependence; valence band.

The spectra of the spontaneous emission from GaAs laser diodes fabricated by vapor phase epitaxy and containing a high degree of compensation in the p-type side of the junction are, in many respects, similar to those previously reported for the cathodoluminescence of homogeneous p-type material. The temperature dependence of the spectra of these diodes supports a model where the emission is attributed to radiative transitions between a narrow band of states near the conduction band edge and an exponential distribution of states extending the valence band into the forbidden gap. An increase in temperature then results in an increase or a decrease in the radiative power output depending on the position of the quasi Fermi level for electrons relative to the above narrow band of states and a distribution of non-radiative levels below it.

Younglove, B. A., Measurements of the dielectric constant of saturated liquid oxygen (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles, Calif.), Chapter in Advances in Cryogenic Engineering 15, Paper No. C−3, 70-75 (Plenum Press, Inc., New York, N.Y., 1970).

Key words: Clausius-Mossotti function; dielectric constant; oxygen; polarizability; saturated liquid.

Dielectric constant measurements of saturated liquid oxygen show a variation of 1.22 near the critical point to 1.57 near the triple point. The calculation "polarizability" (Clausius-Mossotti function) shows a variation of 1.3%, with the maximum occurring at about 150K. The decrease in polarizability near critical is attributed to inaccuracies in the densities in this region. The uncertainty in dielectric constant is about 0.01%.

Other NBS Publications

J. Res. Nat. Bur. Stand. (U.S.), 74B (Math. Sci.), No. 4 (October-December 1970), SD Catalog No. C13.22/ sec.B:74/4. $1.25.

A property of the triangle groups. J. Lehner.

Some theorems on tensor composite graphs. M. F. Capobianco.
The diophantine approximation of roots of positive integers. C. F.
Osgood.

The minimum number of problems to cover all subproblems. H. J.
Greenberg.

Error estimates for the solution of linear algebraic systems. Brother
K. E. Fitzgerald, F.S.C.

On the singular values of a product matrices. W. Watkins.
Contractifiable semigroups. P. R. Meyers.

Publications of the National Bureau of Standards.

J. Res. Nat. Bur. Stand. (U.S.), 74C (Engr. and Instr.) Nos. 3 & 4 (July-Dec. 1970), SD Catalog Number C13.22/sec. C:74/3 & 4. $1.25.

Techniques for comparing four-terminal-pair admittance standards. R. D. Cutkosky.

Some applications for series impedance elements in radio frequency immittance measurements. L. E. Huntley.

A pulse heating method for the measurement of melting point of electrical conductors (thin wires) above 2000 K. A. Cezairliyan. A time-shared computer system for diffractometer control. H. A. Alperin and E. Prince.

Tensile deformation of vapor-deposited copper reinforced with tungsten wires. W. D. Jenkins, W. A. Willard, and D. A. Harne. "Connector-pair" techniques for the accurate measurement of two-terminal low-value capacitances. A. Millea.

The use of dew-point temperature in humidity calculations. L. A. Wood.

Bolovac application for HF and microwave power measurement and standardization. M. C. Selby.

Arp, V., Heat transport through helium II, Cryogenics 10, No. 2, 96-105 (April 1970).

Bridges, J. M., Wiese, W. L., The oscillator-strength scale for Fe I, Astrophys. J. 161, L71-L75 (July 1970).

Brower, W. S., Jr., Fang, P. H., Dielectric constants of scheelite structure crystals, J. Appl. Phys. 40, No. 12, 4988-4989 (November 1969).

Brower, W. S., Jr., Fang, P. H., Dielectric constants of zinc tungstate, J. Appl. Phys. 41, No. 5, 2266 (April 1970). Brower, W. S., Jr., Farabaugh, E. N., Dislocation etchant for single crystal Y2O3. J. Am. Ceram. Soc. 53, No. 4, 225 (April 1970). Cezairliyan, A., High-speed methods of measuring specific heat of electrical conductors at high temperatures (A review), High Temperatures - High Pressures 1,517–529 (1969).

Childs, G. E., Diller, D. E., Refractive index of liquid deuterium, (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles, Calif.), Chapter in Advances in

Cryogenic Engineering 15, Paper No. C-2, 65-69 (Plenum Press, Inc., New York, N.Y., 1970).

Clark, A. F., Childs, G. E., Wallace, G. H., Low-temperature electrical resistivity of some engineering alloys (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles, Calif.), Chapter in Advances in Cryogenic Engineering 15, Paper No. C-5, 85-90 (Plenum Press, Inc., New York, N.Y.. 1970). Daney, D. E., Rapial, A. S., Preparation and characterization of slush hydrogen and nitrogen gels (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles. Calif.), Chapter in Advances in Cryogenic Engineering 15, Paper No. L-4, 467–475 (Plenum Press, Inc., New York, N.Y., 1970). Duncan, A. G., Hiza, M. J., A multipurpose phase equilibrium apparatus to study mixtures of cryogenic fluids: application to argon-methane (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles, Calif.), Chapter in Advances in Cryogenic Engineering 15, Paper No. B-2, 42–45 (Plenum Press, Inc., New York, N.Y., 1970).

Geil, G. W., Feinberg, I. J., Temperature changes in specimens in microplasticity tests, Met. Trans. 1, No. 7, 1845-1851 (July 1970). Giacchetti, A., Stanley, R. W., Zalubas, R., Proposed secondarystandard wavelengths in the spectrum of thorium, J. Opt. Soc. Am. 69, No. 4, 474-489 (April 1970).

Hanson, D. W., Quasi-optical components using total reflection in dielectrics, IEEE Trans. Microwave Theory Tech. MTT-18, No. 4, 233-234 (April 1970).

Hendricks, R. C., Simoneau, R. J., Smith, R. V., Survey of heat transfer to near-critical fluids (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles, Calif.), Chapter in Advances in Cryogenic Engineering 15, Paper No. G-1, 197-237 (Plenum Press, Inc., New York, N.Y., 1970). Heydemann, P. L., Ultrasonic measurements at pressures up to 50 kbar, Proc. Intern. Collog. Solids at High Pressures, Grenoble. France, Sept. 8, 1969, No. 188, pp. 461-467 (Centre National de la Recherche Scientifique, Paris, France, 1970).

Hiza, M. J., Solid-vapour equilibria research on systems of interest in cryogenics, Cryogenics 10, No. 2, 106–115 (April 1970). Kidnay, A. J., Hiza, M. J., Dickson, P. F., Adsorption kinetics in a ternary system containing hydrogen (Proc. 1969 Cryogenic Engineering Conf., June 16-18, 1969, Univ. of California, Los Angeles, Calif.), Chapter in Advances in Cryogenic Engineering 15, Paper No. B-3, 46-49 (Plenum Press, Inc., New York, N.Y.. 1970). LaFleur, P. D., Editor, Activation analysis section: Summary of activities July 1968 to June 1969, Nat. Bur. Stand. (U.S.) Tech. Note 508, 147 pages (July 1970) $1.25, SD Catalog No. C13.46:508. Levin, E. M., X-ray determination of the thermal expansion of silver nitrate, J. Am. Ceram. Soc. 52, No. 1, 53-54 (January 1969). Locke, J. W., Penn, R., Rick, J., Bunten, E., Hare, G., Compilation and use of criminal court data in relation to Pre-Trial Release of defendants: pilot study, Nat. Bur. Stand. (U.S.), Tech. Note 535, 242 pages (Aug. 1970) $1.75, SD Catalog No. C13.46:535. Lutz, G. J., Masters, L. W., Determination of carbon in high purity metals by photon activation analysis, Anal. Chem. 42, No. 8. 948-950 (July 1970).

Marvin, R. S., Rheological Models and measurements (Proc. 5th. Intern. Congress on Rheology, Kyoto, Japan, Oct. 7-11, 1968), Chapter in Fifth International Congress on Rheology, S. Onogi. Ed., 1, 85-96, University of Tokyo Press and University Park Press, Tokyo, Japan, 1969).

Mauvais, C. J., Latanision, R. M., Ruff, A. W., Jr., On the anisotropy observed during the passivation of nickel monocrystals, J. Electrochem. Soc. 117, No. 7, 902–903 (July 1970).

McNish, A. G., Progress on the Metric Study Program, Proc. Conf. 18th Annual Meeting of Standards Engineers Society, Washington. D.C., Sept. 17-19, 1969, pp. 53-56 (Standards Engineers Society. Philadelphia, Pa., 1969).

McNish. A. G., The impact of increasing metric usage, Proc. Conf. Industrial Heating Equipment Association, Spring (77th Consecutive) Meeting, Hot Springs, Virginia, May 19-21, 1969, Exhibit E (Industrial Heating Equipment Assoc., Washington, D.C., 1969). Melmed, A. J., Carroll, J. J., Ellipsometry, LEED, and FEM study of evaporated epitaxial films of iron on (011) tungsten. Surface Sci. Letters to the Editor 19, No. 1, 243-248 (January 1970).