Analytical Chemistry

18589. Newbury, D. E., Myklebust, R. L., Monte Carlo electron trajectory simulation of beam spreading in thin foil targets, (Proc. 2d Cornell Meeting on Analytical Electron Microscopy, Ithaca, NY, July 24-26, 1978), Ultramicrosc. 3, 391-395 (North-Holland Publ. Co., Amsterdam, The Netherlands,

1979).

Key words: analytical electron microscopy; microanalysis; Monte Carlo electron trajectory simulation; spatial resolution; thin foils; x rays.

The spatial resolution of x-ray microanalysis of thin foils is limited by beam spreading caused by elastic scattering of electrons. A simple analytical model with a single scattering approximation which has been used by other workers to calculate the magnitude of beam spreading is reviewed. Monte Carlo electron trajectory simulation techniques are developed to study beam spreading. Equations are given to calculate the three major parameters of a Monte Carlo simulation: step length between scattering points, elastic scattering angle, and azimuthal angle, Monte Carlo results compare well with analytical model calculations for thin films. For thick films, Monte Carlo values of beam spreading are 10% to 40% less than corresponding analytical model values. Beam tailing and the effects of specimen inclination can also be studied by Monte Carlo simulation.

18626. Chabay, I., Rosasco, G. J., Kashiwagi, T., Speciesspecific Raman spectroscopic measurements of concentration fluctuations in unsteady flow, J. Chem. Phys. 70, No. 9, 41494154 (May 1, 1979).

Key words: concentration fluctuations; fast Fourier transforms; Fourier transform analysis; mixing in turbulent flow; noise spectrum; Raman spectroscopy; turbulence.

Concentration fluctuations of specific chemical species in unsteady mixed gas flow were studied by fast Fourier transform (FFT) analysis of Raman intensity. Average concentration and the amplitude and frequency distribution of fluctuations about that average (at a specific Raman shift) can be determined by the FFT/Raman technique. The fluctuation spectra can be modeled to yield information on the lifetimes, periodicity, amplitudes, and the statistical distribution of these in unsteady or turbulent motion. A simple burner with a concentric outer air sheath and inner CH, jet was used in the preliminary experiments for both cold gas and flame studies. Interference from flame emission (uncorrelated to Raman scattering) was minimized by chopping the Raman exciting beam and observing the FFT signal near the chopper frequency. Peak height at the chopper frequency indicates average concentration, while the sidebands around this frequency contain information on the fluctuations in concentration of the species under observation. With the present system, fluctuations in the frequency range of 0-1 kHz having an amplitude of 5% of the average concentration of certain species whose average partial pressure is as little as 1% of atmospheric pressure could be measured. The fluctua

*This listing includes recent NBS papers in the various NBS publications-defined at end of the listing-as well as NBSauthored papers in non-NBS media-identified by 5-digit numbers. Publications with prices and SD stock numbers may be purchased directly from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402 (foreign:

tions are observed from sampling volumes as small as 10mm3 at any position in the flow. Improvements in the technique and extensions to other systems are discussed.

18635. Schreiber, B., Pella, P. A., Application of anionexchange resin-loaded filters to the x-ray fluorescence determination of sulfate, Anal. Chem. 51, No. 6, 783-784 (May 1979).

Key words: anion exchange; filter paper; fuel oil; spectrometry; sulfate; x ray.

A method for the determination of sulfate by enrichment with SB-2 strongly basic anion exchange paper followed by xray fluorescence spectrometry is presented. Enrichment is performed by passing the sample solution through the filters several times. After washing, filters are equilibrated in a barium solution resulting in the stoichiometric uptake of Ba by the sulfate, and the Ba L. x-ray line is measured. Optimum parameters are established for quantitative enrichment and measurement of amounts of 10-1000 μg S.

18643. Blaha, J. J., Etz, E. S., Cunningham, W. C., Molecular analysis of microscopic samples with a Raman microprobe: Applications to particle characterization, (Proc. Ann. Intl. Scanning Electron Microscopy Conf., Washington, DC, Apr. 16-20, 1979), Scanning Electron Microsc. 11, 93-102 (Scanning Electron Microscopy, Inc., O'Hare, IL, 1979).

Key words: atmospheric aerosols; materials sampling; mineralogy; molecular analysis; particle analysis; power plant emissions; Raman microprobe; Raman spectroscopy; urban dusts; vibrational analysis.

A laser-Raman microprobe, developed at the National Bureau of Standards, is used to analyze individual microscopic particles in several investigations. Results are discussed for the detection and identification of the major compounds present in urban airborne dusts and in atmospheric aerosol particles collected at the South Pole. In related studies the microprobe has been applied to the molecular characterization of fly ash particles from power plants with emphasis on the analysis of stack particulates from an oil-fired power plant. A discussion of the identification of calcium-bearing microcrystals as part of a feed utilization study for cattle is presented. In micromineralogical studies performed with the Raman microprobe, a number of common sheet and chain silicates have been investigated to determine possible spectral differences between their fibrous and nonfibrous morphologies. No unique differences could be found between spectra of the different morphologies of the same mineral; however, each mineral had a unique and characteristic spectrum.

The usefulness of the Raman spectroscopic technique as a complement to the methods of electron and ion beam microanalysis is indicated. The discussion of results indicates the unique information that can be obtained through the use of the Raman microprobe.

Atomic and Molecular Studies

Theory of flow-induced fibril formation in polymer solutions, J. D. Hoffman, J. Res. Nat. Bur. Stand. (U.S.), 84, No. 5, 359384 (Sept.-Oct. 1979).

one-fourth additional). Microfiche copies of these GPO-published documents, as well as paper copy and microfiche versions of NBS Interagency Reports (NBSIR), may be purchased from the National Technical Information Service (NTIS), Springfield, VA 22161. Reprints of papers in the NBS Journal of Research and non-NBS media, may often be obtained directly from the authors.

Key words: core fibril; cumulative stress; flow-induced crystallization; nucleation theory; polyethylene; polymer fiber; shish; volume strain.

A treatment of the formation of a basic core fibril (shish) of the type that is generated by flow-induced crystallization of a polymer from solution is given that features the concept of cumulative strain. Multiple nucleation acts by flow-elongated molecules produce an empbryonic fibril that is a connected set of bundlelike nuclei. Surface stress resulting from repulsion of the quasi-random coil chains in the amorphous zone between the nuclei or crystallites builds up at the bundle ends as the nuclei mature, leading ultimately to a high end surface free energy, and to volume strain in the crystallites comprising the core fibril. The theory leads to a stable (or metastable) fibril diameter a, and mean characteristic length 1, with a fixed axial ratio, and predicts why the diameter does not grow further even in a medium that is supersaturated with polymer. The predicted dependence of a,, I,, and the axial ratio, on undercooling is in approximate agreement with experiment. The lattice expansion in the crystal resulting from volume strain is also in fair accord with experiment. The effect of annealing, including the commonly encountered case where the volume strain relaxes to give normal lattice dimensions, but with a high end surface energy still remaining, is noted. The effect of volume strain and the distribution of core fibril lengths about 1, on the melting behavior is calculated. The theory can reproduce crystallinity versus temperature data on polyethylene fibrils. This procedure yields an independent value of 1,. The overall treatment implies that the core fibril is a set of concatenated and substantially extended-chain crystallites with bundlelike ends and a somewhat expanded lattice when unannealed and under tension, the molecular connections between the crystallites consisting of short amorphous ciliary bridges. It is suggested that prolonged annealing at high temperatures can remove a substantial number of the amorphous zones.

18592. Murat, K., Katriel, J., The lowest triplet state of the biexciton may be bound, Phys. Lett. 71A, No. 1, 143-145 (Apr. 16, 1979).

Key words: biexcitons; Haken's Hamiltonian; polar crystals. Using Haken's Hamiltonian and a simple variational wavefunction, the (lo,, lo) state of the biexciton in a polar crystal is found to be stable with respect to dissociation into two ground-state excitons, for a certain range of (realistic) material parameters, unlike the corresponding state in the H2 molecule.

18593. Wiese, W. L., Atomic processes for magnetic fusion research and their data status, (Proc. IX Int. Symp. on Physics of Ionized Gases, Dubrovnik, Yugoslavia, Aug. 28Sept. 2, 1978), Paper in The Physics of Ionized Gases, R. K. Janev, Ed., pp. 661-696 (Institute of Physics, Beograd, Yugoslavia, 1979).

Key words: atomic data; data availability; dielectronic recombination rates; excitation rate coefficients; ionization rate coefficients; magnetic fusion research; transition probabilities; wavelengths.

The role of atomic collision and radiation processes in magnetic fusion research is discussed, using the coronal plasma model as a guide. The data needs and priorities with respect to the type of atomic quantity, chemical element and stage of ionization are reviewed. The status of our knowledge for such atomic data is surveyed, and some of the problems in acquiring them are pointed out. It is shown that reliable atomic data for highly ionized species are very scarce. A few examples for the impact of atomic physics on fusion research are cited.

18595. Warner, B., Apsidal motion and evolution of cataclysmic variables, Acta Astron. 28, No. 3, 303-326 (1978).

Key words: binary stars; cataclysmic variables. Interpreted as apsidal motion, the cyclical orbital period changes of UX UMa and RW Tri indicate highly centrally condensed structures for the secondaries of these systems, suggesting that they are in Case B mass transfer. The consequences are explored of loss of angular momentum (via the accretion disc) from cataclysmic variables, both with and without mass loss from the white dwarfs. Illustrations are given of the resulting mass-radius relationship for the secondaries, and of the change in orbital period during evolution. The observed absence of high-luminosity secondaries (which occur in conservative evolution) is thereby explained.

18598. Harter, W. G., Galbraith, H. W., Patterson, C. W., Energy level cluster analysis for E(v2) vibration rotation spectrum of spherical top molecules, J. Chem. Phys. 69, No. 11, 4888-4895 (Dec. 1, 1978).

Key words: Born-Oppenheimer approximation; high-resolution spectra; level clusters; Raman spectra; rotation-vibration spectra; symmetry analysis.

The theory of level clusters, originally developed for ground state (A,) and weakly coupled infrared active (F2, v) excited states, is extended to include the Raman-active (E) states of vibration-rotation. Simple approximate formulas are given for the eigenvalue spectrum of the dominant second order vibration-rotation Hamiltonian and the results are compared with exact computer reductions.

18599. Harter, W. G., Patterson, C. W., Galbraith, H. W., Centrifugal and Coriolis effects on level cluster patterns for T(v,) rovibrational bands in spherical top molecules, J. Chem. Phys. 69, No. 1, 4896-4907 (Dec. 1, 1978).

Key words: Born-Oppenheimer approximation; centrifugal; Coriolis; frame transformation relations; level cluster, spherical tops; symmetry analysis.

Fundamental T(v) type high-J rovibrational fine structure is derived for a range of values of the Coriolis and [2 × 2]* centrifugal constants. The theory of level clusters is developed further. Correlations are made between cluster states corresponding to well separated P*, Qo, and R- branches, and the opposite case in which II, and Σ, labels are appropriate.

18606. Pasachoff, J. M., Linsky, J. L., Haisch, B. M., Boggess, A., IUE and the search for a lukewarm corona, Sky and Telescope 57, No. 5, 438-443 (May 1979).

Key words: satellites; space astronomy; stars, chromospheres; stars, coronae; stars, late-type; stars, winds; ultraviolet spectra.

Since January 1978, a new telescope in orbit has allowed the world's astronomers to take giant steps toward understanding stars, planets, nebulae, quasars, and other objects by studying their ultraviolet spectra. The International Ultraviolet Explorer (IUE) has coupled significant advances in the instrumentation aloft with interactive capabilities in the control room below in order to allow astronomers to guide and update their projects while the observations are being made. We describe in detail the capabilities of this system.

18609. Harter, W. G., Patterson, C. W., Theory of hyperfine and superfine levels in symmetric polyatomic molecules. Trigonal and tetrahedral molecules: Elementary spin-1/2 cases in vibronic ground states, Phys. Rev. A 19, No. 6, 2277-2303 (June 1979).

Key words: high resolution spectroscopy; hyperfine structure; level clusters; saturation absorption spectra; superfine structure; symmetry analysis; tableau calculus.

A simple approximate scheme for treating molecular hyperfine structure is developed by taking account of energy-level clusters. Unitary tableau and frame transformation techniques are reintroduced. Model Hamiltonians for XY, and XY, (X spin-zero, Y spin-1/2) molecules are developed and solved in cluster bases wich are appropriate for highly excited rotational states. Two cases emerge: Case (1) for which hyperfine splittings are smaller than the "superfine" cluster splittings and case (2) for which superfine splittings are negligible or zero. The problem of correlating energy levels and states between cases (1) and (2) is solved. Since the XY, problem in the elementary cluster bases reduces to (2 × 2) matrices at the worst, the physical interpretation of solutions is not difficult.

18632. Penn, D. R., Effect of bound hole pairs on the d-band photoemission spectrum of Ni, Phys. Rev. Lett. 42, No. 14, 921-925 (Apr. 2, 1979).

Key words: d-band of Ni; excitons; photoemission; satellite and band narrowing.

It is shown that the spectral density of the Nid electrons contains a peak due to excitations of bound hole pairs. The spectral density is observed directly in photoemission experiments which show a satellite peak below the bottom of the d bands. The observed peak exhibits a strong resonance as a function of photon energy and this behavior is also explained by the present theory.

18641. Atkinson, G. H., Parmenter, C. S., Tang, K. Y., Modeto-mode vibrational energy flow in S, benzene. V-V resonant energy transfer, microscopic reversibility, and the role of level degeneracies, J. Chem. Phys. 71, No. 1, 68-72 (July 1, 1979).

Key words: benzene; energy transfer; vibrational energy transfer.

The pattern of mode-to-mode vibrational energy flow from the level v. = 522 cm1 in the S, state of benzene has been studied with OCS as a collision partner. OCS has a near resonant bending vibration v," = 520 cm-1. V-V transfer to this bend of OCS is efficient, requiring only ten collisions. However, a T,R →V transfer from OCS adding v1 = 237 cm to the v' benzene fundamental is even more efficient. Since other V-T,R transfers are also fast, the V-V resonance does not dominate vibrational energy flow pattern from the initially excited benzene level. As with other added gases energy flow is governed by strong propensity rules which can be expressed simply in terms of final level degeneracies, vibration quantum changes, and energy exchange between V and T,R degrees of freedom. Measurements of V-T,R transfer rates from other S, benzene levels with added CO have been used to demonstrate microscopic reversibility and to show the control of transfer rates by the degeneracies of the final level. OCS also quenches the S, electronic state of benzene with a rate constant k = (1.1 ± 0.1) × 10° Torr11 for destruction of the S, state with a 300 K Boltzmann distribution of vibronic levels.

18677. Parmenter, C. S., Seaver, M., A method to estimate intermolecular potential well depths for species in both ground and excited electronic states, J. Chem. Phys. 70, No. 12, 5458-5462 (June 15, 1979).

Key words: excited states; ground state; intermolecular potential; molecules; well depths.

The relationship_Inơμ = InC + [(€,*,*) (€μm)]1/2/kT correlates the cross sections σ for a state change A→B induced by a series of added M gases with the intermolecular potential well depths for A*...A* pairs and M...M pairs. This correlation is used with literature data concerning A* → B to deduce €** for electronically excited atoms (Na, Ne, Ar, Xe) and electronically excited molecules (I2, SO2, CH3OH, glyoxal, propynal, benzene). The well depths are generally observed to exceed the ground state values by factors of 2-10. Large well depths are also observed for sec-butyl radicals and for the CH, ion with high vibrational excitation. The correlation also provides an alternate means to measure ground state well depths EMM. In cases where secure comparisons are available, the well depths so derived usually lie within 20% of values found from transport measurements or virial coefficients. The correlation seems a useful alternative to empirical estimating procedures when data from conventional methods are available.

not

18689. Smith, E. W., Giraud, M., Temperature dependence of rotational linewidths in HCl perturbed by argon, J. Chem. Phys. Lett. to Ed., 70, No. 4, 2027-2028 (Feb. 15, 1979).

Key words: HCI-Ar; rotational linewidths; temperature dependence; theoretical and experimental comparison; vibrational effect.

The temperature dependence of several rotational linewidths in HCl perturbed by argon is studied. Comparison of theoretical and experimental data indicate that there may be a vibrational effect (i.e. an increase in halfwidth due to distortion of the molecular potential curves for higher vibrational levels) which is strongest at low temperatures.

SP549. Proceedings of the National Conference on Regulatory Aspects of Building Rehabilitation. Proceedings of a Conference held at the National Bureau of Standards, Gaithersburg, MD, Oct. 30, 1978, S. A. Berry, Ed., Nat. Bur. Stand. (U.S.), Spec. Publ. 549, 220 pages (Aug. 1979) SN003-00302107-5, $5.50.

Key words: building; code administration; codes; evaluation; existing buildings; performance standard.

This document contains the edited Proceedings of the National Conference on Regulatory Aspects of Building Rehabilitation held Oct. 30, 1978, at the National Bureau of Standards.

It contains a total of 18 presented papers, all of which address the subject of rehabilitation-currently a critical issue in the Nation's effort to revitalize its cities and house its citizens.

Public sector, as well as private sector programs and experiences toward achieving this goal are covered in one general and three technical sessions.

TN996. Mechanical properties of adobe, J. R. Clifton and F. L. Davis, Nat. Bur. Stand. (U.S.), Tech. Note 996, 45 pages (May 1979) SN003-003-02066-4, $2.25.

Key words: adobe; adobe soil; compressive strength; creep; flexural strength; mechanical properties; moisture; nondestructive testing; preservation.

Relationships between the compressive strength and creep, and the moisture contents of adobe were investigated. Moisture was found to have a deleterious effect on these mechanical properties of adobe, its severity increasing with increasingly higher relative humidities and higher moisture contents. It was concluded that rain and ground water would have a greater deleterious effect on the mechanical properties of adobe than high relative humidities.

The physicochemical properties of adobe, mix proportions, drying conditions, and shrinkage of specimens were also found to influence the compressive strength of adobe. Procedures for preparing, curing and testing of adobe specimens are given.

A nondestructive test method, based on measuring the penetration resistance of adobe, was found to give reliable predictions of the compressive strength and moisture content of adobe specimens.

18596. McNall, P. E., Jr., The relation of thermal comfort to learning and performance: A state-of-the-art report, (Proc. ASHRAE Semiannual Meeting on HVAC-Human Factors, Philadelphia, PA, Jan. 28-Feb. 2, 1979), Paper PH-79-9, No. 2 in ASHRAE Trans. 85, Pt. 1, 759-767 (June 1979).

Key words: air-conditioning; comfort; education; environment; human factors; research; school.

The results of several research projects are summarized. These projects have attempted to relate thermal comfort, learning and productivity. They show indications of positive correlation (optimal comfort appears to result in maximum learning, etc.) but these are not well supported by commonly accepted experimental statistics. The problem seems to rest in quantifying highly variable individual human motivation as other experimental conditions are varied. This seems particularly true in the usually employed experiments of a few hours' duration on many human subjects. On the other hand, investigating longterm effects of fatigue and motivation over many weeks is expensive and time-consuming, and control of the subjects when they are not under the experimental conditions has been minimal in studies of this type up to the present time.

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, $7.25.

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.

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.

18688. Simiu, E., Scanlan, R. H., Flutter of a plate-like member in horizontal fluctuating flow, Eng. Struct. 1, No. 4, 207-210 (July 1979).

Key words: aerodynamic stability; aeroelasticity; fluctuating flow; flutter; suspended-span structures; time-dependent loads.

A procedure is presented for determining the mean flutter velocity of a symmetrical plate with a vertical and a torsional degree of freedom in a flow with periodic horizontal fluctuations. Expressions of the self-excited forces based on a generalized Theodorsen-type model are used. The resulting flutter motion is described by a system of generalized Mathieu-Hill equations to which the stability criteria of the theory of dynamic systems with periodic coefficients are applied. A numerical example is given for a plate with mechanical characteristics comparable to those of a suspension bridge in a flow with fluctuations comparable to those occurring in natural winds. It is found that the effect of such fluctuations upon the value of the mean flutter velocity is negligible. This suggests that in investigating the aerodynamic stability of a suspension bridge with characteristics similar to those dealt with in the paper, it is permissible to neglect the effect of the horizontal fluctuations of the flow. Recently obtained experimental results are quoted which tend to confirm this result.

Computer Science and Technology

SP500-52. Computer science & technology: Computer performance evaluation users group (CPEUG). Proceedings of the Fifteenth Meeting held at San Diego, CA, Oct. 15-18, 1979, J. E. Weatherbee, Ed., Nat. Bur. Stand. (U.S.), Spec. Publ. 500-52, 240 pages (Oct. 1979) SN003-003-02118-1, $5.50.

Key words: computer performance evaluation; computer performance measurement; computer performance prediction; computer system acquisition; conference proceedings; CPE in auditing; hardware monitoring; CPEUG; installation management; on-line system evaluation; prediction methods; queuing models; simulation; software monitoring; workload definition.

The Proceedings record the papers that were presented at the Fifteenth Meeting of the Computer Performance Evaluation Users Group (CPEUG 79) held October 15-18, 1979, in San Diego, California. With the theme "The Expanding Scope of CPE," CPEUG 79 focused on changes in CPE techniques that will occur in an era of increased use of distributed processing techniques. The program was divided into two parallel sessions with one session devoted to the presentation of technical papers on previously unpublished work and the other devoted to tutorials and case studies. The technical papers fall into one of two general categories, (1) application of CPE in installation management and (2) methods and tools of CPE as a technical discipline, and are presented in the Proceedings in their entirety. Summaries of several of the tutorials and case studies are also presented in the Proceedings.

SP500-53. Computer science & technology: Technology assessment: ADP installation performance measurement and reporting, C. B. Wilson, Nat. Bur. Stand. (U.S.), Spec. Publ. 50053, 37 pages (Sept. 1979) SN003-003-02123-7, $2.00.

Key words: computer performance evaluation (CPE); computer performance management (CPM); installation management; installation performance management; performance measurement and reporting; resource management; standard performance measures.

This report compares the current status of ADP installation performance measurement and reporting in the Federal ADP community with the best practices as found in the Federal and private sectors and described in the literature. The comparison reveals that more effort could be expended by Federal sites in the area of computer performance management. The principal obstacles to more and better performance programs are perceived to be the lack of needed measures on many systems and the magnitude of the effort involved in accessing and analyzing the measures which are available. The report discusses several underlying causes for these obstacles and makes three recommendations which could partially relieve the situation: (1) development of standard performance measures, (2) development of a Government-wide data base for normative performance ranges, and (3) development of statistical computer performance evaluation techniques.

SP500-54. Computer science & technology: A key notarization system for computer networks, M. E. Smid, Nat. Bur. Stand. Spec. Publ. 500-54, 35 pages (Oct. 1979) SN003-003-021300, $1.75.

Key words: cryptography; digital signatures; encryption; identifiers; key management; key notarization.

A cryptographic, key notarization system is proposed for computer networks to protect personal (nonshared) files, to communicate securely both on and off-line with local and remote users, to protect against key substitution, to authenticate system users, to authenticate data, and to provide a digital signature capability using a nonpublic key encryption algorithm. The system is implemented by addition of key notarization facilities which give users the capability of exercising a set of commands for key management as well as for data encryption functions. Key notarization facilities perform notarization which, upon encryption, seals a key or password with the identities of the transmitter and intended receiver.

TN1108. SPEED2, a computer program for the reduction of data from automatic data acquisition systems, R. D. Peacock and J. M Smith, Nat. Bur. Stand. (U.S.), Tech. Note 1108, 153 pages (Sept. 1979) SN003-003-02112-1, $4.75.

Key words: computer program; data acquisition systems; data reduction; plotting.

The voluminous amount of data that can be collected by automatic data acquisition systems requires the use of a digital computer for the reduction of data. A general purpose computer program for the reduction of data collected by automatic data acquisition systems is presented. The program is written with the ability to accept data from a number of different data acquisition systems, with the ability to check the correctness of data included. Through the use of FORTRAN computer programming, the data can be converted to meaningful scientific and engineering units. The data can then be presented in tabular, printer plot or ink pen plot form.

The program is documented, and detailed instructions for its use, with examples, are presented. The use of SPEED2 requires some knowledge of FORTRAN programming language and the executive control language for the computer system in use. 18597. Molino, B. B., Hilsenrath, J., Beyond data retrieval: An outline of the unique data analysis features of the NBS Omnidata system, Proc. Eighteenth Annual Tech. Symp. on Information Systems-Effectiveness for the User, Gaithersburg, MD, June 21, 1979, pp. 159-165 (The Washington DC Chapter of the Association for Computing Machinery, Washington, DC, June 1979).

Key words: Boolean search system; computer programs; curve fitting; data analysis; data base management; data retrieval; file handling; graphic analysis; IMS information retrieval; KWOC indexing; least-squares; linear regression; MIS; plotting; statistical analysis.

Omnidata is an interactive, general-purpose system for data retrieval, data analysis, and data file maintenance. The system is specifically designed so that individuals with little or no background in computers are able to search data files, do analysis on these files, and prepare ad hoc or periodic reports. At the same time, the system provides the computer professional and data-base administrator with tools for proper maintenance of those data bases under his control. This wide spectrum of functions of varying complexity is provided by the modularity of the system. In addition to the 'usual' capabilities of a data management system-searching, reporting, sorting, updating-there are close to 40 distinct modules to provide detailed statistical and graphical analysis, data manipulation, and file management.

Discussion will include descriptions of some of these unique data manipulation and analysis modules, including AGGREGATE, CROSSTAB, DISTRIBUTE, SURVEY, and TALLY. Also included will be a discussion of how Ominidata interfaces with the OMNITAB statistical and plotting programs.

Consumer Information and Protection

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, $4.50.

Key words: consumer products; human factors; human performance; 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.