< 20K. A summary of results is presented which indicates that (1) the decrease in conductivity is large (up to 80%) for the copper specimens and somewhat smaller (up to 50%) for aluminum alloy, (2) the Fe-Ni alloys are only slightly affected (up to 8%), (3) the effect on stainless steel S31000 (AISI 310) is approximately twice that of S30400 (AISI 304), and (4) the Ti-6Al-4V alloy shows a reasonably small percentage effect, but the largest difference with temperature of all of the materials tested. The relative importance of the nagnetothermal effect compared to that of thermal history and material variability is discussed.

18621. Tobler, R. L., McHenry, H. I., Reed, R. P., Fracture mechanics parameters for an iron-13% chromium-19% manganese stainless steel and its welds at cryogenic temperatures, (Proc. 2d Int. Cryogenic Materials Conf., Boulder, CO, Aug. 3-5, 1977), Paper K-7 in Advances in Cryogenic Engineering, K. D. Timmerhaus, R. P. Reed, and A. F. Clark, Eds., 24, 560-572 (Plenum Press, New York, NY, 1978).

Key words: crack propagation; fatigue; fracture resistance; low temperature tests; mechanical porperties; stainless steel.

As part of the USA/USSR Science & Technology exchange program on the properties of LNG containment materials, fatigue crack growth rates and fracture toughness tests at selected temperatures between 295K and 4K were conducted on an Fe-13% Cr-19%Mn-0.2% N austenitic stainless steel from the USSR. Compact specimens (18.4 mm thick) and threepoint bend specimens (12.5 mm thick) were used in testing the normalized base metal and submerged arc welds. The fatigue crack growth resistance decreases as temperature is decreased from 295 to 4K. Fracture toughness also decreases, with Jie values ranging from 255 to 50 kJm2 between 295K and 4K. The effects of welding are discussed, and specimen orientation is shown to be one of the most significant factors governing the fatigue crack growth resistance of the butt welds. For TS orientation, crack growth rates are higher in the HAZ and for TL orientations crack growth rates are lower in the HAZ, compared to the base metal.

18666. Hamilton, C. A., Harris, R. E., Sullivan, D. B., Highspeed superconducting electronics, (Proc. Government Microcircuit Applications Conf., Monterey, CA, Nov. 14-16, 1978), GOMAC 1978 Digest of Papers VII, 29-32 (1979).

Key words: high speed logic; Josephson computer; Josephson junction; microstriplines; superconductivity. Superconducting electronics is an emerging technology which offers significant performance advances in digital computers and high-speed instruments. These advantages include low dissipation, high speed and packing density, and dispersionless transmission lines.

18695. Tobler, R. L., Reed, R. P., Fatigue crack growth resistance of structural alloys at cryogenic temperatures, (Proc. 2d Int. Cryogenic Materials Conf., Boulder, CO, Aug. 3-5, 1977), Paper A-7 in Advances in Cryogenic Engineering, K. D. Timmerhaus, R. P. Reed, and A. F. Clark, Eds., 24, 8290 (Plenum Press, New York, NY, 1978).

Key words: crack propagation; fatigue; low temperature tests; nickel alloys; stainless steels; steels; superalloys; titanium alloys.

Fatigue crack growth rate data at selected temperatures including 295, 76, and 4 K are presented for a variety of titanium alloys, stainless steels, and Fe-Ni alloys. The results correlate well with crystal structure. Compared to their behavior in a room temperature air environment, stable austenitic face-centered cubic alloys exhibit improved fatigue crack growth re

sistance at low temperatures. Hexagonal close-packed titanium alloys show temperature-insensitive behavior. Temperature effects on the fatigue crack growth resistance of body-centered cubic Fe-Ni alloy steels are moderate, except below the fracture transition temperature range where fatigue crack growth rates are drastically accelerated.

Standard Reference Materials

SP260-65. Standard reference materials: Micro-homogeneity studies of NBS standard reference materials, NBS research materials, and other related samples, R. B. Marinenko, K. F. J. Heinrich, and F. C. Ruegg, Nat. Bur. Stand. (U.S.), Spec. Publ. 260-65, 84 pages (Sept. 1979) SN003-003-02114-1, $3.50.

Key words: digital periodic integrator; electron microprobe; homogeneity; standard reference materials; steel.

A simple routine technique for studying homogeneity in the micrometer range with the electron microprobe has been developed. For graphic display, a digital periodic integrator is used. In conjunction with scalers and a stepping motor on the sample stage, traces similar to industrial control charts based on comparison of the experiment with the expected (Poisson) counting statistics are quickly obtained. A computer program has been developed to numerically evaluate sample homogeneity.

Several Standard Reference Materials (SRMs) have been tested. These include the iron and steels (SRMs 661-664, 461, and 463), the gold-copper and gold-silver alloys (SRMs 481 and 482), the tungsten-20 percent molybdenum alloy (SRM 480), cartridge brass (SRM 478), the iron-chromium-nickel alloy (SRM 479a). A Research Material, Glasses for Microanalysis (RM-30), has also been tested.

SP260-66. Standard reference materials: Didymium glass filters for calibrating the wavelength scale of spectrophotometers-SRM 2009, 2010, 2013, and 2014, W. H. Venable, Jr. and K. L. Eckerle, Nat. Bur. Stand. (U.S.), Spec. Publ. 26066, 85 pages (Oct. 1979) SN003-003-02127-0, $3.50.

Key words: bandwidth; didymium glass filter; passband centroid; spectrophotometer; transmittance; wavelength standard.

This publication presents the use of didymium glass filters as Standard Reference Materials (SRM). The standard reference materials are labeled 2009, 2010, 2013 and 2014 depending on size and method of calibration. The certification and uncertainties are also discussed. An appendix with background material and terminology is included. Wavelengths of minimum transmittance and inflection points in the transmittance curve are certified to be at specified wavelength and provide a convenient method of calibrating the passband centroid of spectrophotometers with bandwidths between 1.5 and 10.5 nm.

18668. Hust, J. G., Graphite as a standard reference material, (Proc. 15th Intl. Thermal Conductivity Conf., Ottawa, Ontario, Canada, Aug. 24-26, 1977), Paper in Thermal Conductivity 15, V. V. Mirkovich, Ed., pp. 161-167 (Plenum Press, New York, NY, 1978).

Key words: characterization; density; electrical resistivity; graphite; Lorenz ratio; reference materials; thermal conductivity.

The Cryogenics Division (Boulder, CO) in conjunction with the Office of Standard Reference Materials (Gaithersburg, MD) of the National Bureau of Standards has been investigating graphite as a potential, extended temperature range, Standard

Reference Material (SRM). A large number of isotropic, finegrained graphite rods in various diameters have been obtained for homogeneity and stability investigations. Electrical resistivity and density measurements have been performed on numerous rods at temperatures from 4 to 300 K. Thermal conductivity measurements have been performed on thirteen specimens at about 20 °C. These measurements show that transport property variations both between and within these rods is relatively large (approximately 10%). However, a correlation between these variables is shown to exist which will allow the calculation of thermal conductivity from simple and inexpensive electrical resistivity and density measurements to within about 2%.

Surfaces and Interfaces

Observations of surface changes in platinum crucibles, C. P. Saylor, E. Wichers, and J. I. Hoffman, J. Res. Nat. Bur. Stand. (U.S.), 84, No. 5, 385-394 (Sept.-Oct. 1979).

Key words: contrast augmentation of reflecting surfaces; double-diaphragm; faces (crystal) on platinum crucibles; hematite forming on platinum; iron as alloy in platinum; platinum ware; surface of platinum influenced by method heating.

Ion which has been in solid solution in a platinum crucible will cause iron determinations in analyses to become high. Likewise the iron, oxidizing to ferric oxide during ignition, segregates along the boundaries between platinum crystals. It causes embrittlement and eventual crumbling of the crucible.

During these studies it was observed that after heating in an electric muffle furnace the surface of a crucible was covered by tiny crystallographic faces. When, however, heating to the same temperature was carried out in a gas flame the facets almost smoothed out of existence.

Technology Incentives

NBS-GCR-ETIP 79-63. Environmental regulation in theory and practice: EPA's process of setting best practicable control technology standards, W. A. Magat, L. P. Gianessi, and W. Harrington, 175 pages (Dec. 1978). Order from NTIS as PB297499, $8.00.

Key words: administrative experimentation; best practicable technology; clean water regulation; Environmental Protection Agency; evaluability assessment; evaluation; Experimental Technology Incentives Program; regulatory experimentation; regulatory policy; rulemaking; technological innovation.

This document is a report of work carefully laying out the rulemaking process that had been used at EPA to prepare a large number of highly technical regulations in the clean water area. It is one product of the Regulatory Processes and Effects Project of the Center for Field Methods (ETIP). The broader project, described elsewhere, is attempting to analyze the effects of changes in regulatory processes on industrial innovation. Under a subcontract to the project, Resources for the Future has carefully examined and laid out the steps that were followed to convert the legislative mandate into actual writing and issuance of permits.

Section I introduces the study of rulemaking and some of the reasons for carrying it out. Section 2 covers the "Best Practicable Technology" rulemaking process in detail. Section 3 contains a review of much expert literature and its applicability here. Section 4 discusses a methodology for continuing the project. Much supporting material is contained in an appendix.

ETIP's next steps to build on this work would be to expand it in a similar level of detail into industry and industrial effects and to work from both the industrial and rulemaking domains simultaneously.

NBS-GCR-ETIP 79-64. Regulatory administrative experiment manual, J. N. Nay and J. Waller, 114 pages (June 1979) Order from NTIS as PB298446, $6.50.

Key words: administrative experimentation; evaluability assessment; evaluation; experimental methods; Experimental Technology Incentives Program; regulation; regulatory oversight; regulatory processes and regulatory effects; regulatory reform; social science; technological innovation. This document is an interim repository of material related to methods and processes for carrying out regulatory administrative experiments. It is one product of the Regulatory Processes and Effects (RPE) Project of the Experimental Technology Incentives Program (ETIP). The broader project, described in greater detail elsewhere, is attempting to analyze the effects of changes in regulatory processes on industry and industrial innovation. The development and testing of methods and processes for carrying out this work is one of several related aspects of the RPE project.

The first two chapters provide an introduction to ETIP, the specific program involved, and the RPE project. Chapter III describes Evaluability Assessment, one of the methods used in this work. Chapter IV outlines the general approach to carrying out the work. The last chapter is an outline for reporting on interim progress of experimental situations. Two appendices are included.

Thermodynamics and Chemical Kinetics

Enthalpies of solution of the nucleic acid bases. 5. Adenine in aqueous hydrochloric acid, aqueous sodium hydroxide, methanol, and ethanol, M. V. Kilday, J. Res. Nat. Bur. Stand. (U.S.), 84, No. 3, 231-240 (May-June 1979).

Key words: adenine; enthalpy of dissociation; enthalpy of protonation; enthalpy of reaction; enthalpy of solution; nucleic acid bases; solution calorimetry; thermochemistry. The two preceding papers in this series described the results of measurements of the enthalpies of solution in water for some of the bases of the nucleic acids. In this work the enthalpies of solution or reaction of adenine (Ade), CH,N1 or 6-amino purine, in other solvents are reported.

Sample preparation in ion-chromatography, W. F. Koch, J. Res. Nat. Bur. Stand. (U.S.), 84, No. 3, 241-246 (May-June 1979).

ion

Key words: conductivity; ion-chromatography; exchange; liquid chromatography; oil; oyster. lon-chromatography, a relatively new technique in analytical chemistry, has already shown great promise toward solving complex trace analysis problems, in particular the speciation and quantitation of anions. It is especially attractive to the field of microanalysis. The method of sample preparation, however, is crucial in order to realize this capacity. Existing microanalytical methods nearly always must be modified to be compatible with ion-chromatography, and often, more extensive sample cleanup is required than is needed for "single species" methods. These considerations have been applied to the determination of chloride and bromide in waste oil, and to the analysis of oyster tissue. Pretreatment with polystyrene resin and ion-exchange resin is discussed.

Miniaturization of normal-state and superconducting striplines,

R. L. Kautz, J. Res. Nat. Bur. Stand. (U.S.), 84, No. 3, 247259 (May-June 1979).

Key words: copper; niobium; stripline; superconductivity; surface impedance.

The properties of normal-state and superconducting striplines are calculated as a function of miniaturization. For normal conductors the Reuter-Sondheimer theory is applied in order to account for the effects of finite film thickness and mean free path. For superconductors the Mattis-Bardeen theory is used in order to include effects due to the energy gap. Calculations for three example conductors, copper at 295 K and 4.2 K and niobium at 4.2 K, examine the attenuation, dispersion, and characteristic impedance of striplines as a function of frequency and dielectric thickness. Simulations of pulse transmission are used to evaluate the utility of the example striplines for high-speed digital applications.

Enthalpies of solution of KBr, KI, KIO3, and KIO, in H2O, M. E. Efimov, G. N. Klevaichuk, V. A. Medvedev, and M. V. Kilday, J. Res. Nat. Bur. Stand. (U.S.), 84, No. 4, 273-286 (July-Aug. 1979).

Key words: endothermic solution reactions; enthalpy of solution; KBr, KI, KIO,, KIO,; solution calorimetry; thermochemistry; tris(hydroxymethyl)aminomethane.

Enthalpy of solution measurements of four potassium salts in H2O were made in either an adiabatic or an isoperibol calorimeter or both (see p. 273 for table summarizing).

The value for KIO, has been corrected for the hydrolysis of the periodate ion. The AC, = −(82.5 ± 4.3)J·mol-1· K-1 for the unhydrolysed reaction. For the reaction of KBr in H2O, AC, was measured as −(166.6 ± 7.2)J·mol1K-1 in the temperature range 298 K to 319 K.

18671. Lin, H. M., Seaver, M., Tang, K. Y., Knight, A. E. W., Parmenter, C. S., The role of intermolecular potential well depths in collision-induced state changes, J. Chem. Phys. 70, No. 12, 5442-5457 (June 15, 1979).

Key words: collisions; cross sections; intermolecular potential; state changes; well depths.

A relationship is developed from two distinct theoretical approaches to correlate the rate constants ky or cross sections σ for a series of added gases M which collisionally induce a state transformation A* → B. The correlation derived from theory is

Ino = InC + E-/kT,

where C is a constant and A-M is the intermolecular well depth between A* and M. We observe that experimental data can be described by a related correlation

Inσ = InC + ẞ(€μm/k)1/2,

where ẞ is a constant and E is the well depth between pairs of M molecules. This correlation is shown to be general. It works for electronic state deactivation in atoms, intersystem crossing and internal conversion in S, polyatomics, rotational and also vibrational relaxation in S, polyatomics, predissociation in diatomics and polyatomics, and vibrational relaxation in a free radical as well as in a molecular ion. The theory is ap

propriate only when attractive forces dominate the interaction, and this seems consistent with the experimental data. The correlation thus provides a simple means to distinguish between attractive and repulsive interactions. The correlation also reveals that collision partners do not substantially modify the intrinsic S1-T mixing during collision-induced intersystem crossing.

✩U.S. GOVERNMENT PRINTING OFFICE: 1979 O-311-057/1