Page images
PDF
EPUB

5.14. NBS INTERAGENCY REPORTS

A special series of interim or final reports on work performed by NBS for outside sponsors (both government and non-government). In general, initial distribution is handled by the sponsor; public distribution by the National Technical Information Service (NTIS), Springfield, VA 22161, in paper copy or microfiche form unless otherwise stated. When ordering this series from NTIS you must order it by the “COM, PB, or AD" number listed at the end of each entry.

Recommended design loads are based on the average maximum event in a time interval of 1000 seconds and are tabulated for assumed basic wind speeds of 70 and 90 mph (31 and 40 m/s) and a moderately open wind exposure.

NBSIR 77-1298. Power lawn mowers: Ease of pull, V. J.

Pezoldt and J. J. Persensky, 32 pages (June 1977). Order from NTIS as PB271974.

NBSIR 75-935. The National Measurement System for electrici

ty, N. B. Belecki, B. L. Dunfee, and O. Petersons, 86 pages (Sept. 1978). Order from NTIS as PB299158.

Key words: calibrations; dissemination of units; electrical measurements; electric power measurements; electrotechnology; impact of measurements; measurement technology assessment; National Measurement System;

standards. The National Electrical Measurement System, by which all measurements of electrical quantities are made in the U.S., is reviewed. This overview, based on the results of a four-year study, details the organizational structure of the system; the technical aspects of realizing, maintaining, dissemination and using the units for measurements; and the economic characteristics of its basic industry, the instrumentation industry, and the system's user constituency. Documentary standards and the organizations producing them are discussed, concluding with a survey of presently adopted documents. Its two major components, the electronics subset and the electric power subset, are defined, described, and contrasted. Major technical, management, and logistics problems facing the system are delineated. An in-depth view of the Electricity Division, which supplies the measurement base of the system, is given. Finally, recommendations for technical and management action by NBS in a number of areas are given.

Key words: consumer products; human factors; human per

formance; lawn mowers; psychophysics; safety; standards. This study was designed to provide objective information about the subjective judgement of “easy to pull" as it relates to the effort required to restart manual pull-start power lawn mowers. Seventy-four lawn mower users performed a total of more than 10,000 pulls on two simulated pull-start mechanisms. The peak forces applied in the pulls were associated with the subjects' judgements about the ease or difficulty of the pulls. These data were used to generate sample distributions of the maximum forces judged easy and the minimum forces judged hard. While not providing a definitive answer to the question of what is easy to restart, the data generated in the study provide a practical basis upon which an upper force limit for easy to restart can be based.

NBSIR 77-1299. Power lawn mowers: Time-to-blade access, A.

M. Ramey and J. J. Persensky, 22 pages (May 1977). Order from NTIS as PB297641.

Key words: consumer product; human factors; lawn mowers; reaction time; safety; standards.

a

NBSIR 77-1289. The measurement of wind loads on a full-scale

mobile home, R. D. Marshall, 132 pages (Sept. 1977). Order from NTIS as PB297463.

This document is the final report for the Consumer Product Safety Commission of an investigation of time-to-blade access for walk-behind power mowers. The problem studied was: “How long after the dead-man control is released should a lawn mower blade be allowed to rotate?" The Human Factors Section at NBS performed this empirical study of operator movement time to determine an ergonomically sound recommendation for blade stopping time.

One hundred participants were tested using a reaction time device designed to measure mower users' approach times to various areas of potential blade contact. The test apparatus permitted measurement of both reaction time-or time to release a simulated dead-man control at the onset of a cue light and, more importantly, movement time-or the time from the release of the dead-man control to activation of one of five switches in the blade access area.

Analysis of the data reveal no statistically significant differences in reaction time as a function of movement distance. As expected, however, movement time does increase linearly as movement distance increases. The range of average movement times observed was from 0.6 to 3.3 seconds. The median movement time at the shortest and longest distances were 1.4 and 2.2 seconds respectively. An inspection of percentile information for movement time suggests a blade-stopping time of 0.7 seconds in order to protect the maximum number of people.

Recommendations for needed further research are discussed.

Key words: aerodynamics; building; codes and standards;

full-scale testing; mobile homes; wind loads. An experimental investigation of wind loads acting on a fullscale mobile home is reported. The objectives of the investigation were (1) the direct measurement of surface pressures and overall drag and lift forces, (2) the formulation of recommended loads for the design of mobile homes and their anchoring systems to resist forces due to wind and (3) the measurement of deflections and the identification of failure modes with application of simulated wind loads.

Measurements were obtained for a variety of wind speeds and relative wind directions using a mobile home with nominal plan dimensions of 12 by 60 ft (3.7 by 18.3m). Wind speeds were measured at five levels ranging from 3 to 18m and the mean velocity profiles were found to be best described by a power law with exponent a = 0.18. Extreme negative pressure fluctuations were found to occur on the end walls and along the perimeter of the roof. The resonant component of response of the mobile home to drag and lift forces is negligible for basic wind speeds up to 90 mph (40 m/s) and the average maximum lift loads are not strongly influenced by the presence or absence of skirting.

[ocr errors]

NBSIR 77-1401. Processing and characterization of NBS stan

dard polyethylene for use as a negative control material, A. J. Bur, 32 pages (Jan. 1978). Order from NTIS as PB297464. data center output. The functions of the programs are outlined and the associated operating procedures are described in detail. Full documentation of the programs is presented in a separate report.

NBSIR 78-1433. Low velocity performance of a bronze bearing

vane anemometer, L. P. Purtell, 23 pages (Feb. 1978). Order from NTIS as PB291366.

Key words: biomaterials; negative control; polyethylene; processing sheets and rods; surface characterization; sur

face contamination. This work was initiated in order to fulfill a need for a polymer which can serve as a negative control material for biocompatibility studies involving new polymer implant materials. Two large batches of well-characterized polyethylene resin are the sources of the candidate negative control material. The original polyethylene resin, in pellet form, was processed into sheets and rods and examined for surface contaminants and uniformity. Surface observations consisted of measurements of contact angle, attenuated total reflectance infra-red absorption and secondary ion mass spectroscopy (SIMS). Bulk measurements consisted of density, differential scanning calorimetry, and transmission infra-red spectroscopy. All of the measurements, except SIMS, indicated that the material was uniform and typically polyethylene with no macroscopic contamination. The SIMS measurement, which is a sensitive analytical tool for detecting low levels of elemental contamination, showed significant differences between the types of contamination on the surfaces of the starting material and the type of contamination on the processed sheet and rod. The method of processing was also significant because the extruded rod showed much more contamination than did the compression molded sheet. The surfaces of the rod were found to contain metallic oxides and several other metals which were not present in the unprocessed polyethylene. It is concluded that close attention must be paid to the method of processing and that only a sensitive analytical tool such as SIMS can be used to detect surface contamination and the differences between these samples.

Key words: airflow; anemometer; laser velocimeter; low

velocity; performance; vane anemometer; wind tunnel. Performance of a bronze bearing vane anemometer is evaluated over the speed range of 64 to 690 feet per minute includ. ing starting speed and stopping speed. The tests were performed in the NBS Low Velocity Airflow Facility which provides a uniform flow of low turbulence and utilizes a laser velocimeter as the velocity standard.

NBSIR 78-1444-3. Semiconductor technology pro

gram-Progress briefs, W. M. Bullis, Ed., 16 pages (Oct. 1978). Order from NTIS as PB292681.

Key words: electronics; integrated circuits; measurement technology; microelectronics; semiconductor devices; semiconductor materials; semiconductor process control; silicon.

NBSIR 78-887. Development and evaluation of an LNG sam

pling measurement system, W. R. Parrish, J. M. Arvidson, and J. F. LaBrecque, 200 pages (July 1978). Order from NTIS as PB289938.

Key words: custody transfer, density; gas analysis; gas chromatography; heating value; hydrocarbon; liquefied natural

gas; phase equilibrium; pipelines; sampling. This report describes the development and evaluation of procedures and components for sampling and analyzing LNG from flowing streams. Laboratory and field test results showed the total uncertainty in the computed heating value of samples taken with the recommended sampling system could be routinely within 1 0.3 percent; this included the + 0.1 percent uncertainty in analysis by gas chromatography. Three sample probes and two vaporizer designs were considered. Of the ten operating variables considered, six were found to be important in sampling. Test results were used to establish recommended design and operating criteria.

This report provides information on the current status of NBS work in measurement technology for semiconductor materials, process control, and devices. Results of both inhouse and contract research are covered. Highlighted activities include: determination of resistivity-dopant density relationships in silicon; measurement of ion-implanted dopant profiles by spreading resistance; optical measurement of line widths on chrome photomasks, iron-oxide photomasks, and silicon wafers; additional data on sulfur impurity levels in silicon; conduct of a workshop on stability of thin film solar cells; analysis of leakage currents in gated diode test structures; calculations of the radiation dose incurred by oxide layers during X-ray and e-beam lithographic steps; correlation of selected electrical parameters on commercial rectifier diode wafers; and availability of a test patter for determining alignment between mask levels. In addition, brief descriptions of new and selected ongoing projects are given. The report is not meant to be exhaustive; contacts for obtaining further information are listed. Compilations of recent publications and publications in press are also included.

NBSIR 78-1478. A universal set of test data for computer imple

mentations of elementary mathematical functions, D. W. Lozier, 29 pages (May 1978). Order from NTIS as PB291961.

Key words: elementary function testing; Fortran library test data; Fortran library testing; mathematical function testing; test data for elementary functions; test data for mathematical functions.

NBSIR 78-1432. Automation of the ion energetics data center,

R. Thompson, W. Webb, and H. M. Rosenstock, 84 pages (Dec. 1977). Order from NTIS as PB293918.

a

Key words: abstract; appearance potential; archival tape; computer program; data base; data base management; empirical molecular formula; GPSDC; ion energetics; ioniza

tion potential. The lon Energetics Data Center is engaged in the compilation, evaluation and dissemination of experimental information on gaseous ion energetics. Outputs include bibliographic and tabular information on ionization potentials, appearance potentials, electron affinities and heats of formation of gaseous positive and negative ions. The operation of the data center is discussed. This operation has recently been automated by the development of a set of computer programs, called IONPACK, which minimize the manual effort required for the numerous file manipulations and editing steps necessary to produce the

A short table of values of 20 mathematical functions commonly found in computer libraries is given. The data was chosen to sample the functions throughout the range of a typical floating-point arithmetic. Computer implementations can be tested by comparing computed function values against the tabular values. A discussion on how to interpret the test results is included, for both decimal and non-decimal implementations.

NBSIR 78-1494. Test procedures for the determination of the

gross calorific value of refuse and refuse-derived-fuels by oxygen bomb calorimetry. Summary of the 1977 fiscal year results, D. R. Kirklin, D. J. Mitchell, J. Cohen, E. S. Domalski, and S. Abramowitz, 35 pages (Dec. 1978). Order from NTIS as PB290160.

test

values for occupant-use variables will result in a better correlation between the energy use predicted for buildings being designed today and the actual energy use of the buildings when occupied.

NBSIR 78-1505. Characteristics of helicoid anemometers, J. M.

McMichael and W. G. Cleveland, 17 pages (Aug. 1978). Order from NTIS as PB291987.

Key words: bomb calorimetry; gross calorific values; refuse-derived-fuels; sample characterization;

procedures. Gross calorific values have been determined for refusederived-fuels (RDF) from two manufacturers, Teledyne National and Combustion Equipment Associates. Test procedures used are modifications of those used for coal and coke. The calorific values (moisture. and ash-free basis) obtained for Teledyne National RDF ranged from 24.51 to 25.20 MJ kg' (10539 to 10835 Btu lb-') with a standard deviation of 0.8 percent. The calorific values (moisture- and ash-free basis) of Combustion Equipment Associates ECO-FUEL II RDF ranged from 21.93 to 22.16 MJ kg' (9427 to 9528 Btu 16-') with a standard deviation of 0.4 percent. Results of 23 laboratory samples are presented at various stages of sample preparation which were derived from single field samples from each of the two sources. Calorimetric results based on an equilibrated laboratory sample are presented along with some semi-quantitative spectrochemical results. The results indicate that the techniques of oxygen bomb calorimetry can be successfully applied to a non-homogeneous refuse stream after considerable processing to prepare a “homogeneous” refuse-derived-fuel (RDF).

Key words: air; anemometer; helicoid anemometer; lag;

overspeeding error; rotary anemometer; unsteady flow. An experimental study of the overspeeding error for helicoid anemometers in periodic air flows is described. The ranges of amplitude and frequency for which a simple nonlinear model for the dynamic response of such instruments remains valid are presented. It is shown that the model is valid for typical atmospheric applications of such instruments. A simple method is presented whereby the effects of inertial lag and nonlinearity may be taken into account in obtaining measurements of alongwind power spectra in the atmosphere.

NBSIR 78-1507. Some thoughts on electrical connections, J.

Rabinow, 35 pages (Aug. 1978). Order from NTIS as PB290491.

Key words: aluminum wiring; electrical connections; pressure terminals; wire creep.

NBSIR 78-1496. Preliminary data on the field performance of

storage-type residential water heaters, R. A. Grot and L. S. Galowin, 27 pages (Apr. 1979). Order from NTIS as PB295431.

Key words: energy usage; load profiles; water heaters. The early results of a field experiment for determining the performance of gas and electric residential storage water heaters are presented. Energy requirements for hot water supply and hot water consumption and usage pattern data are presented and analyzed using statistical techniques in order to display average load curves and the variation about the average. It is shown that the daily energy usage of these water heaters is approximately a linear function of the energy content of the drawn daily water consumption. This fact allows a simple procedure to be used for evaluating the effects of retrofit actions on the performance of the water heater.

This report is a subjective and personal statement of my experiences and thoughts regarding electrical connections, in general, and aluminum wiring for homes, in particular. It is not a statement of official position of the National Bureau of Standards (NBS). It is entirely possible that other members of the NBS staff may not agree with many statements made in this report. It is based on some considerable experience and where the ideas expressed are not based on such experience, I hope this is clearly indicated.

My conclusions are that present day technology of electrical distribution wiring in residences is not in keeping with good engineering practices available today. This is true relative to both copper and aluminum wiring.

NBSIR 78-1501. Quantified occupant-use factors affecting ener

sy consumption in residences, R. E. Clark and S. R. Hastings, 143 pages (July 1979). Order from NTIS as PB298052.

Key words: appliance energy consumption; energy consumption of residences; lighting energy consumption; occupant factors; residential air conditioning, service hot water;

space heating; ventilation. Predicting energy consumption for a building requires three types of data: climatic data, component performance data, and occupant-use data. Historically, few data on occupant use of a building have been collected, and the data which are collected are not easily referenced. Consequently, it is common for enersy analysts to establish values for occupant variables merely on the basis of their own personal experience. In response to this dilemma, this report assembles residential energy-use-data, as could be found, from field metering studies, surveys, utility company estimates, and government sponsored statistical projections. From these data the authors have determined recommended occupant-use values based on their analysis and judgments. These “recommended values" represent the best judgment of the present authors, but are not to be interpreted as “NBS recommended" values. Data, and assessment of their validity for input in models for predicting energy consumption, are organized into six groups by energy end-use: (1) heating, (2) service hot water, (3) appliances, (4) lighting, (5) air conditioning, and (6) ventilation. The use of more soundly derived

NBSIR 78-1509. An algorithm and basic computer program for

calculating mple coal gasification equilibria, W. S. Horton, 83 pages (Aug. 1978). Order from NTIS as PB291241.

Key words: BASIC; carbon dioxide; carbon monoxide; coal gasification; COLGAS; hydrogen; interactive computer program; methane; minimization of Gibbs energy; phase

rule; simultaneous chemical equilibria; water. Calculation of the equilibrium composition for the gases CH,, CO, CO2, H2, and H2O is treated by minimizing the Gibbs energy, G. Minimization is constrained by the conservation of chemical elements. With the use of Lagrangian multipliers, the minimum is found by setting the partial derivatives of G with respect to the amount of each substance equal to zero. The resulting non-linear equations are solved iteratively by the Newton-Raphson method. This algorithm is implemented with an interactive computer program written in the BASIC language named COLGAS. The aim of this work was to provide people who test materials in coal-gasification-like atmospheres an easy way to obtain the equilibrium composition of their gas mixtures. A knowledge of computer programming is not required in order to use the program. A listing of the program is given and also six sample computer calculations. The phase rule is applied to the C-H-O system and two ternary diagrams are shown illustrating the condensation of solid carbon and liquid water.

NBSIR 78-1521. French schools—A report of the U.S. team visit

to France from November 13 to 23, 1977, P. Driscoll, Coor

[blocks in formation]

By June 1970, the National Bureau of Standards and the Centre Scientifique et Technique du Batiment had effectively begun a cooperative program in building technology. The purpose of this program was to increase jointly the French and United States capability to develop building sciences and technology; seek answers to significant building problems; and reduce costly and wasteful duplication of parallel national efforts. This collaboration has provided opportunities for representatives of both nations to exchange ideas, skills, information and techniques in attacking problems of particular mutual interest. These opportunities have included the exchange of selected literature, with translations of main papers and publications; the exchange of long-term interns working in the organization of the other country on subjects requiring special facilities; work by one organization for the benefit of the other not as well equipped, either in staff or in equipment; and the exchange of missions of experts from one country to the other to study special work. It is precisely this exchange of missions of experts, to study specific work, that produced the report which follows.

NBSIR 78-1547. Methodology for choosing test parameters to

evaluate protective headgear, R. E. Berger and N. J. Calvano, 77 pages (Nov. 1978). Order from NTIS as PB292284.

Key words: headform; headgear; head injury; helmet; im

pact; test method. The effects of changing test variables (headform, impact velocity, impact surface, impact site) on output parameters (peak acceleration, severity index) were studied. Twelve football helmets representing six different types of energy absorbing systems were used in the test. Results show good correlation between metal and humanoid headforms during top impacts but poor correlations when helmets were impacted on the back. Correlation between impact surfaces was high. Peak acceleration correlated well with severity index.

[ocr errors]

NBSIR 78-1526. Annual conference on fire research, C. Hug

gett, Ed., 217 pages (Dec. 1978). Order from NTIS as PB291930.

[merged small][ocr errors][ocr errors]

Key words: combustion products; fire hazards; fire model

ing; fire research; human behavior in fires. This report contains extended abstracts of grants and contracts for fire research sponsored by the Center for Fire Research, National Bureau of Standards and descriptions of the internal programs of the Center for Fire Research.

NBSIR 78-1555. A system for fire safety evaluation of health

care facilities, H. E. Nelson and A. J. Shibe, 146 pages (Nov. 1978). Order from NTIS as PB292273.

Key words: automatic sprinklers; building codes; building construction; Delphi Method; fire safety; health care facilities; hospitals; interior finishes; Life Safety Code; nursing homes; risk analysis; safety equivalency; safety evaluation;

smoke detection. A quantitative evaluation system for grading health care facilities in terms of fire safety is described. The system can be used to determine how combinations of widely accepted fire safety equipment and building construction features may provide a level of safety equivalent of that required by the widely accepted Life Safety Code of the National Fire Protection Association. The system will provide flexibility to both the designer of new facilities and to the renovator of existing health care facilities.

Three major concepts form the basis for code equivalency: a. Occupancy Risk—the number of people affected by a given fire, the level of fire they are likely to encounter, and their ability to protect themselves; b. Building Safety Features-the ability of the building and its fire protection systems to provide measures of safety commensurate with the risk; c. Safety Redundancy-in-depth protection, through the simultaneous use of alternative safety methodologies such as containment, extinguishment, and people movement methodologies. The design of the complete fire safety system is intended to ensure that the failure of a single protection device or method will not result in a major failure of the entire system.

In this system, equivalency is judged to exist when the total impact of the occupancy risk factors and the compensating building safety features produce a level of safety equal to or greater than that achieved by rigid conformance to the explicit requirements of the NFPA Life Safety Code. In this evaluation, safety performance is gauged both in terms of overall safety impact and depth of redundance.

NBSIR 78-1539. Mathematical models for selecting catalogs of

standard-sized items, D. R. Shier, 80 pages (Sept. 1978). Order from NTIS as PB289803.

Key words: catalog; dynamic programming; iterative

procedure; models; optimization; stability; standards. This report identifies and discusses various mathematical models for selecting a "best" catalog of standard sizes. A survey of existing models for continuous and discrete versions of the catalog selection problem is presented. The advantages and disadvantages of such models are assessed with regard to both range of applicability and computational feasibility. This evaluation shows that frequently-advocated iterative procedure may produce erroneous results and identifies another approach as the most promising. Various refinements and extensions are then proposed for this latter (discrete) model and its associated solution technique (dynamic programming). In particular, a multidimensional version of the catalog selection problem is formulated and analyzed. Areas for further investigation, and unresolved issues, are also discussed.

a

NBSIR 78-1556. Kitchen range energy consumption, J. V.

Fechter and L. G. Porter, 68 pages (Mar. 1979). Order from NTIS as PB294880.

NBSIR 78-1545. Low velocity performance of a high speed vane

anemometer, L. P. Purtell, 23 pages (Sept. 1978). Order from NTIS as PB291409.

Key words: airflow; anemometer; laser velocimeter; low

velocity; performance; vane anemometer; wind tunnel. Performance of a high speed vane anemometer is evaluated over the speed range of 43.4 to 741 feet per minute including starting speed and stopping speed. The tests were performed in the NBS Low Velocity Airflow Facility which provides a uniform flow of low turbulence and utilizes a laser velocimeter as the velocity standard.

Key words: appliance; cooking; efficiency; energy; human

factors; kitchen ranges; labeling; stoves; test methods. In support of the national appliance energy conservation program, the National Bureau of Standards (NBS) has been developing, evaluating, and recommending standard methods for measuring appliance energy efficiency. This report describes a study where 58 non-professional cooks prepared 21 standard meals each on kitchen ranges, and compares the results with a laboratory test method which does not utilize such cooks. Ten different ranges were tested-five gas and five electric. The results are (1) the rank order (least to most efficient) cor

ceilings— The state-of-the-art and a plan for future research work, J. G. O'Neill, 29 pages (Jan. 1979). Order from NTIS as PB291889.

relations between laboratory measured efficiency and energy used by cooks were not significantly different, (2) the cooking practices of the 58 cooks were sufficiently alike that no major modification to the laboratory test method was required, (3) homemakers showed greater variability in energy use than did laboratory tests with the same ranges, (4) energy consumption labels on appliances should include information about that variability, and (5) evaluation of range efficiencies could be done with only three to five energy intensive meals. NBSIR 78-1558. Development of hydrogen and hydroxyl con

tamination in thin silicon dioxide thermal films, S. Mayo and W. H. Evans, 39 pages (Mar. 1979). Order from NTIS as PB293556.

Key words: dry oxidation of silicon; hydrogen contamination; hydroxyl contamination; semiconductor device fabri

cation; silicon; silicon dioxide; thermal oxidation of silicon. Hydrogen and hydroxyl incorporation into thin silicon dioxide films thermally grown on silicon in dry oxygen atmospheres contained in resistance-heated fused silica or polycrystalline silicon tubes is analyzed. The mechanisms leading to incorporation of these impurities in the film are discussed in terms of trace water and hydrocarbon contamination in the oxygen used, room ambient humidity permeation through the fused silica tube, the silicon wafer preparation prior to oxidation, and other environment factors. The most significant reactions occurring the water-silica-silicon system during wafer oxidation at temperatures in the range from 800 °C to 1200 °C are discussed. It is shown that, during the oxidation period required to grow a 100-nm thick silicon dioxide film on a < 100 > silicon wafer in nominally dry oxygen containing water contamination in the ppm range, the introduction of hydrogen and hydroxyl contamination into the oxide film can be explained in terms of the water-silica interaction. The use of polycrystalline silicon oxidation tubes is discussed with reference to the inherent water gettering action of silicon at oxidation temperatures. NBSIR 78-1564. Tabulation of published data on electron

devices of the U.S.S.R. Through December 1976, C. P. Marsden, 137 pages (Dec. 1978). Order from NTIS PB291959.

Key words: automatic sprinkler; building code; smoke movement; spray nozzle; stairway protection; ventilated

stair. A review of literature was conducted to determine the stateof-the-art of automatic sprinkler, sprinkler-vent and spray nozzle methods of protecting openings in fire resistive assemblies. A review of nationally used model building codes and standards indicated that they have varying provisions for these types of systems. Generally, the use of these systems is only applied to escalator openings in fully sprinklered buildings. Previous experimental work, however, demonstrated that these systems can also be effective in preventing passage of heat and smoke through other types of openings in structural assemblies.

An outline of a planned research project and a description of the test facility are given. The project will develop design parameters for sprinkler-vent and spray nozzle methods for protecting stairways and other openings through floor ceiling assemblies. Results from this project may suggest improvements to current codes and standards involving these systems and possibly permit their wider use in unsprinklered buildings.

NBSIR 78-1573. Properties and interactions of oral structures

and restorative materials, J. M. Cassel, 94 pages (Dec. 1978). Order from NTIS as PB289913.

as

Key words: electron devices; electron tubes; semiconduc

tors; U.S.S.R. This tabulation includes data on U.S.S.R. electron devices as collected from publications, mostly handbooks published by the various ministries and institutes of the U.S.S.R. Information is given on all active devices ranging from receiving to microwave devices, semiconductor devices, and miscellaneous devices such as photographic flash tubes and thermistors.

Key words: accelerator; alloy; base metal; casting; com

posite; cyanoacrylate; dental alloy; initiator; resin; wear. To improve the storage stability of dental composite resin systems, alternative catalyst systems to the commonly used benxoyl peroxide-tertiary amine are being developed. Increased storage stability is attainable with organic peresters or hydroperoxides but requires more efficient accelerators than the presently used amines. Ascorbic acid or ascorbyl palmitate offer promise as useful accelerators which give good biocompatibility. To develop more reactive amine accelerators with perhaps less toxicity than those currently in use, Pdimethylamino-phenylacetic acid (or ester derivatives) and dimethylaminoglutethimide were synthesized and shown to yield composite restorative specimens of good mechanical strength and color stability. A wide range of cyanoacrylates from the simplest, 2-ethyl cyanoacrylate, to the more complex type such as viscous isoamyl product have been examined for their capacity to achieve and retain bonding between acrylic resin and dentin. Very high initial bond strengths were achieved with isobutyl-2-cyanoacrylate on dentin pretreated with dilute acid but a one-month thermal cycling test in water indicated the bonding was not sufficiently stable. Initial pin on disc wear measurements with a synthetic hydroxyapatite pin have shown promise.

A pattern modification to reduce variability in the alloy castability test has been developed. Variations in the number of firing cycles and amount of condensation of green porcelain have been shown to cause significant differences in dimensional characteristics on cooling of fused dental porcelain.

NBSIR 78-1569. End-of-year-report. Micromechanical proper

ties of beryllium and other instrument materials, B. W. Christ, R. S. Polvani, and R. J. Hocken, 42 pages (Oct. 1978). Order from NTIS as PB299654.

Key words: beryllium; dimensional stability; gyroscope; instrument materials; microcreep; micromechanical proper

ties. This research program was initiated on October 1, 1977. It is sponsored by the Office of Naval Research. The objective of the program is to evaluate and understand the micromechanical properties of beryllium and other instrument materials for use in gryoscopes, so that dimensional stability can be improved. Improved dimensional stability is expected to lessen the need to periodically align gyroscopes in service. NBSIR 78-1571. Sprinkler-vent and spray nozzle systems for

fire protection of openings in fire resistive walls and

NBSIR 78-1575. Erosion by solid particle impact, A. W. Ruff

and S. M. Wiederhorn, 103 pages (Jan. 1979). Order from NTIS as PB291988.

Key words: abrasives; ceramics; erosion; impact; metals;

particle erosion; wear. A review of the methods and findings associated with solid particle impact erosion of metals and ceramics is presented. Modem theories of particle erosion and critically reviewed experimental observations are brought together and compared.

« PreviousContinue »