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An extensive literature review on the potential energy surfaces of fifteen atmospheric triatomic molecular systems has been made. The systems are water, nitrogen dioxide, ozone, carbon dioxide, nitrous oxide, and their singly charged positive and negative ions. The potential energy surface characteristics for each molecular system are summarized in the form of adiabatic correlation diagrams between the electronic states of the triatomic molecule and those of the atom, diatomic asymptotes. Where available information allows, such correlation diagrams are constructed not only for the equilibrium symmetry and geometry of the triatomic ground state, but also for other symmetries and geometries as appropriate to the clear indication of the three-dimensional surface characteristics and the general adiabatic asymptotic correlations. The correlation diagrams for each system are discussed in connection with some of its triatomic and atom-diatomic processes.

This report documents the three year investigation by the National Bureau of Standards into the technical issues involved in providing a uniform user and program environment for (possibly concurrent) access to multiple heterogeneous remote database management systems. This report is an anthology of papers prepared by the investigators which identify and discuss the design, development and implementation of such a user interface, and the development of a demonstrable prototype. (Author)

This report describes the second year of an effort to demonstrate an ultra-high-speed analog-to-digital converter using superconducting electronics. A converter was fabricated and tested, producing 200 to 700 megasamples per second. Experimental and theoretical support work is also presented. (Author)

The widely used procedures for calibrating gage blocks by comparison with blocks of known length generally lack the redundancy needed to evaluate measurement uncertainty of the controls needed to monitor the process on a continuing basis. This report provides a detailed description for the systematized intercomparison of groups of four nominally equal gage blocks using an electromechanical comparator. Two of the blocks are unknowns and two are standards. The process provides the redundancy needed for evaluating uncertainty and for continuous monitoring. Gage block thermal effects, equalization time, handling techniques, and observation sequence are described.

The process of calibrating a small number of 'unknown' standards relative to one or two reference standards involved determining differences among the group of objects. Drift, due most often to temperature effects, or a 'left-right' polarity effect can bias both the values assigned to the objects and the estimate of the effect of random errors. This note presents schedules of measurements of differences that eliminate the bias from these sources in the assigned value and variances at the same time gives estimates of the magnitude of these extraneous components. The use of these designs in measurement process control is discussed and a computer program in BASIC is presented. (Author)

Many of the gage block comparators that are in use have not been periodically evaluated by the user. It is the intent of this report to set forth guidelines and procedures that may be used conveniently by metrologists to aid in obtaining more meaningful comparisons of gage blocks by the use of probe-type transducers. The methods described for the cleaning and deburring of gage blocks can be useful to those individuals who have not established formal laboratory procedures for these operations. Many individuals may employ valid methods that vary somewhat from those employed at the National Bureau of Standards.

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. (Author)

A plasma poling device is described which allows essentially instantaneous poling of polymeric films at room temperature at very high fields. Using poly(vinylidene fluoride) both undrawn (comprising essentially pure alpha conformation) and biaxially drawn (both alpha and beta conformation) were polarized in this manner. The polarization of the sample was determined from current integration measurements. The piezoelectric and pyroelectric coefficients were then measured and compared with those estimated from the polarization theory of Mopsik and Broadhurst, which expresses these coefficients as linear functions of polarization. The theory gives an accurate representation of the piezoelectric coefficients, but underestimates the pyroelectric coefficients considerably.

Fourier analysis, applied to the recently introduced thermal pulse method, yields new and unique relations between the time-dependent, pyroelectric response of a thin specimen and the Fourier coefficients of the charge or polarization distribution across its thickness. The new analysis is applied illustratively to thermal pulse data for a vinylidene fluoride copolymer electret. (Author)

An alternative method for controlling the mobile-ion contamination in the oxidation ambients for MOS device processing is explored. Mobile-ion contamination in silicon dioxide films thermally grown in dry oxygen at 1000 C on silicon substrates has been studied by use of a double-wall fused-silica oxidation tube. The space between the tubes were alternatively filled with chlorine, room air, or sodium hydroxide gas to determine if a correlation exists between the presence of these substances in the jacket and the mobile-ion density in the oxide films. MOS capacitors were prepared on these films and mobile-ion densities were measured using conventional c-v techniques. The ion densities ranged from 10 to the 13th power to 10 to the 10th power/sq cm as a function of the jacket atmosphere. These preliminary results suggest that there is a correlation between the presence of cleaning or contaminating agents in the jacket and the mobile-ion density in the oxide films. Both cleaning and contaminating actions occur through the tube wall. (Author)

The adsorption of formaldehyde (H2CO), hydrogen, and carbon monoxide on Ru(110) has been studied using angle-integrated ultraviolet photoemission spectroscopy (UPS) and temperature programmed desorption (TPD). The UPS spectra for low exposures of H2CO at 80 K indicate that H2CO dissociates to a substantial degree. These spectra are compared with UPS spectra for the sequential adsorption of hydrogen and CO. Whereas there are similarities between these spectra, the differences in the UPS, work function change, and TPD results are sufficient to suggest that a portion of the dissociated H2CO may exist as a surface molecular complex containing H and CO. This is apparently the first reported example, based on a UPS study, of an oxygen-containing organic molecule which dissociates upon adsorption on a metal surface at 80 K. For high exposures at 80 K, adsorption of a condensed layer of molecular H2CO is observed. (Author)

This report addresses a number of aspects involved in using a Scanning Electron Microscope (SEM) for radiation testing of semiconductor devices. Problems associated with using the low energy electron beam to simulate 60Co exposure and a method for estimating the total absorbed dose in critical device oxides are discussed. The method is based on the experimentally determined expression for electron energy dissipation versus penetration depth in solid materials of Everhart and Hoff. An appendix giving the method of estimating the total absorbed dose in a form sutiable for ASTM deliberations is included. (Author)

A description is given of the molecular and morphological structure of polyvinylidene fluoride and from this description a classical model is proposed for calculating the piezo- and pyroelectric properties. The model consists of an array of crystal lamellae with a net moment from aligned dipoles in the crystals and compensating space charge on the crystal surfaces. The results for no compensation and complete compensation essentially bracket experimentally observed results and indicate that the largest contribution to the activity of this polymer arises from bulk dimensional changes, rather than from changes in molecular dipole moments. (Author)

Experimental results are presented for the effects of Reynolds number and angle-of-attack on the static pressure distribution and the location of laminar to turbulent transition for the flow over several blunt noseforms; comparisons are made with analytical methods. (Author)

The refractive index of fusion cast CaF2 was measured at room temperature over the wavelength range 0.2144 micrometers to 8.662 micrometers and the data were fitted to a Selmeier type equation. Measurements of refractive index of hot forged CaF2 were extended to the wavelength range 0.2024 micrometers to 0.2483 micrometers. Data are presented for dn/dT of single crystal specimens of CaF2, BaF2, reactive atmosphere processed (RAP) KC1 and KBr, LiF, NaF, and 2SrF2, and polycrystalline chemical vapor deposited (CVD) ZnSe and ZnS. The measurements were done by the method of Fizeau interferometry over the temperature range -180 deg to 200 deg C at the wavelengths 0.6328 micrometers, 1.15 micrometers, 3.39 micrometers and 10.6 micrometers. Data are presented for the refractive indices, the linear thermal expansion and dn/dT of Lexan and Plexiglas 55. (Author)

The Electron Stimulated Desorption Ion Angular Distributions (ESDIAD) method has been used to study the adsorption of H2O by Ru(001). The results indicate that chemisorbed, undissociated H2O is bonded to Ru via the oxygen atom, and that interactions between neighboring molecules occur as coverage increases. The utility of ESDIAD for structure determination in the absence of long range order is demonstrated. (Author)

This report provides detailed technical material on various energy conservation actions for existing Air Force facilities and utility systems. It is specifically tailored to serve as a working document for Base engineers and technical personnel. The report covers energy conservation for Air Force facilities, including the equipment for providing hot water, space heating and cooling, lighting, and humidification. It also covers central plant systems and underground distribution systems (hot water, steam, and chilled water). This volume includes the following topics: Energy Conservation Measures for Exterior Building Envelopes; Modifying Mechanical Systems and Operating Practices for Energy Conservation; Conducting the Building Survey; Measurements for identifying Energy Conservation Potential; Economic Analysis; and Appendices--Heat transfer fundamentals, Solar energy systems for Air Force applications, Heat and Chilled water distribution systems, and Survey of computer programs for evaluating building and system performance., See also Rept. no. AFCEC-TR-77-11, AD-A041 086.

The adsorption of NH3 and H2O on Ru(001) have been studied using the Electron Stimulated Desorption Ion Angular Distribution (ESDIAD) method, in conjunction with thermal desorption spectroscopy and LEED. The results suggest that chemisorbed NH3 and H2O are bonded to Ru via the N and O atoms, respectively, with H atoms pointed away from the surface. The utility of ESDIAD for determination of structures of adsorbed molecules is indicated., Presented at International Vac. Congress (7th) and International Conference on Solid Surfaces (3rd), Vienna, 1977.

General and specific guidelines to be followed by USAF management personnel have been developed and tabulated in this report. These guidelines include, for example, establishing management structures to implement the detailed energy conservation programs, analyzing alternative energy conservation options for most of the Air Force Base facilities, family housing units, and special buildings. The guidelines are to be helpful for establishing and implementing short- and long-range plans for energy management, gaining support of all Base and tenant personnel, and monitoring program progress. (Author), See also Rept. no. NBSIR-77-1238, AFCEC-TR-77-12.

This report presents a detailed method for the measurement of collector-emitter saturation voltage. The method which is included in the Appendix is proposed for standardization. The report also contains a description of the laboratory confirmation of the method and a discussion of the precautions to be taken to assure repeatability of the measurement. Emphasized is the necessity to determine that the conditions for saturation are met during the measurement. (Author)

Using molecular dynamics, a study was made of the transport of energy in perfect, crystalline solids subjected to heating and to mechanical compression. Two aspects were emphasized in the approach to these problems. (1) careful evaluation of the validity of the model and (2) detailed analyses of the mechanisms of energy transport and energy sharing. This report summarizes the results of the study. The conclusion reached indicates that many features related to the transport of energy in the model are indeed realistic and therefore it is of interest to study the mechanisms involved with a view to gaining a more detailed understanding of the process of energy sharing and of approach to equilibrium. (Author)

This report consists of the following four parts: Field Ion Microscopy Studies of the Interaction of Hydrogen with Selected Metals and Alloys; The Role of Noncrystalline Films in Passivation and Breakdown of Passivation; Effect of Chromium Depletion on the Repassivation Kinetics 18-10 Austenitic Stainless Steel in Sodium Chloride Solutions; and Composition of Surface Films Formed During the Repassivation of Iron and Iron-Molybdenum Alloys. (Author)

The water tunnel described produces sinusoidal flow with peak velocities adjustable from 0 to at least 30 centimeters per second for any period between 3 and 25 seconds. The tunnel is of U-tube design with the middle horizontal part comprising the test section. The vertical end parts are two cylinders with tight-fitting pistons at one end, and two reservoirs open to air at the other. The pistons are driven by a variable-speed electric motor, with an adjustable counterweight permitting operation at resonance at any period. (Author)

?27This report consists of four parts as follows: (1) A study of the influence of Mo in Fe-Mo alloys on crevice corrosion. It was found that 5% Mo is needed to affect repassivation in a crevice. (2) The description of a new technique for measuring repassivation rates in a crevice. (3) A description of alloys prepared to simulate the composition of metal near grain boundaries of sensitized austenitic stainless steel. These alloys are used for studies of the effect of sensitization on repassivation kinetics. (4) A review of new approaches in the study of localized corrosion., See also report dated Oct 75, AD-A019 648.

The U. S. commitment ot a voluntary conversion to metric units raises changeover problems in the field of air traffic control and airspace management. This report begins by discussing current practice in altitude measurement and the rules for height maintenance now in effect worldwide. Four desirable features are given for an altitude measurement system, encompassing both the units of height measurement and the designation of cruising levels. Three alternative bases for the design of such a system are discussed and related to the desirable characteristics. Problems associated with each of the approaches are discussed and the many factors to be considered and the many interrelationships involved are examined. (Author)

As part of a program to develop better quality assurance in the measurement of total dose in the field of radiation-hardness testing of electronic devices, a survey was conducted at twelve radiation test facilities. The survey was carried out through personal visits during which various characteristics of the test facilities and dosimetry procedures were noted. This report summarizes the results of the survey. Particular attention is given to the types of dosimetry problems perceived by the dosimetry personnel at the facilities as well as to general observations by the surveyor. The observations and information obtained through this survey led to some conclusions on where problems in total-dose measurements may occur. Some specific recommendations result and give direction to the program plan for developing more consistent measurement procedures within the radiation-hardness testing community. (Author)

The objective of this work was to develop information to support a proposed flammability standard for flight attendant uniforms. Currently used uniforms were found to burn to varying degrees when exposed to a temporary small ignition source. The feasibility of designing uniforms with improved fire safety is demonstrated. Trade-offs in terms of cost, appearance, serviceability, and comfort are discussed. A proposed flammability standard for flight attendant uniforms is included. It describes the tests and qualifying criteria needed to add self-extinguishing characteristics and heat flux resistance to various types of F/A uniform items. (Author)

This report identifies and evaluates those existing and potential standards which will be useful to the Air Force in the development and implementation of integrated computer aided manufacturing (ICAM) systems. Such systems, when implemented by the Air Force and by Air Force contractors, will increase productivity in discrete part batch manufacturing by several thousand percent. The use and importance of standards are considered in the context of CAM systems. Since the Air Force will develop the detailed ICAM architecture after this study is complete, existing system concepts and architectures are examined to identify the common elements to guide the further presentation and discussion of relevant standards. (Author)

Investigations on piezoelectricity and pyroelectricity in crystalline polymers have been carried out using a copolymer of vinylidene fluoride and tetrafluoroethylene which crystalliezes directly from the melt into a polar crystal form. The crystalline fraction is easily varied from 0.35 to 0.5. Alignment of the dipoles in an applied electric field appears to approach saturation electric fields of 250 kV/cm, independent of poling temperatures between 0 and 80 C. Piezoelectric responses from samples of varying crystallinity are consistent with increased polarization and lower compressibility as the degree of crystallinity is increased. Thermal pulse experiments reveal that when poled at room temperature, only a thin region near the positive electrode is poled but the thickness of this region increases with an increase in poling temperature. Copolymer films crystallized from the melt in the presense of a field show greatly improveed stability of piezoelectric activity when stored at elevated temperatures compared with samples poled only after crystallization. The room temperature poling of polyvinylidene fluoride using a corona discharge has been confirmed. Preliminary results are presented which imply that even the non-polar alpha phase of the polymer may be poled in this way but it is unstable--especially at elevated temperatures. (Author), Original contains color plates: All DDC reproductions will be in black and white.

The Kerr coefficients of both water and nitrobenzene were measured and the variation of these quantities with temperature and wavelength was investigated. At a temperature of 296 K and at a wavelength of 632.8 nm, the following values for the Kerr coefficients were obtained B(C6H5NO2) = 3.24 x 10 to the -12th power m/V sq., and B(H2O) = 3.43 x 10 to the -14th power m/V sq. The estimated uncertainty in the measurement in nitrobenzene is + or - 6 percent while in water the estimated uncertainty is + or - 8 percent. The primary conclusion drawn is that although nitrobenzene can be used for accurate measurement of a wide, and fairly well defined, variety of high voltage pulses, the situation in water is more poorly understood. The primary areas of difficulty using water are the existence of turbulence under pulses of duration of a few microseconds and the possibility of a voltage dependence of the Kerr coefficient due to a saturation of the alignment of the molecules with the applied field. (Author)

Government sponsored research and development on semiconductor devices intended for application in radiation environments often relies on test structures arranged into test patterns for device design information and process characterization. Problems unique to a radiation environment are often analyzed using test structures such as MOS capacitors and break-out transistors. The work reviewed in this report demonstrates the importance of test structures in isolating and identifying problem areas. However, the measurement methodology associated with test structures is seldom reported which makes it difficult to compare the results of different workers. Also, the work reported to date using test structures and test patterns for assessing radiation effects has involved the relatively slow-speed laboratory testing of statistically insignificant numbers of test structures. Test patterns could be used by buyers of radiation hardened devices for (1) vendor selection and qualification, (2) process validation for hardness screening and hardness assurance, and (3) identification of circuit parameters critical to hardness assurance.

Excitation of nitrogen and oxygen molecules is the primary event in the excitation of the atmosphere. Theoretical calculations of the electronic properties of these molecules required for the prediction of optical emissions from normal and disturbed atmospheres have been made, including the analysis of the electronic structure of excited states of nitrogen. (Author)

This paper is divided into two parts. Firstly, a review of desorption methods is presented, with emphasis on the use of temperature programmed desorption (TPD) and electron stimulated desorption (ESD) for understanding the bonding of adsorbed species to surfaces. Secondly, recent studies of the angular distribution of ESD ions from adsorbed layers on W(011) are discussed. The ESD of O(+) ions from oxygen adsorbed on a stepped W(011) surface is shown to be sensitive to the presence of atom steps. (Author)

Both E-glass and Kevlar 49 (aramid) fibers were used to reinforce an isophthalic polyester resin. These materials were used, in turn, to form pultruded antenna rod hardware for structural tests. The aramid material exhibited substantially improved strength-retention properties over the glass-reinforced material under prolonged exposure to heat and humidity. The aramid material offers the promise of superior weatherability in antenna-support applications although further testing is warranted. The stress-rupture properties of pultruded rod, under high humidity, possess unusual temperature and time dependencies. These are explained in terms of the mechanisms whereby moisture is transported from the environment to the fiber/matrix interface. The stress-rupture properties, as well as the tensile properties, may be improved by appropriately modifying the pultrusion process. Two new end fittings, generally capable of attaining the full tensile strength of glass fiber-reinforced pultruded rod, were developed. Several new test methods were developed, including and environmental stress-rupture test, two methods for investigating the quality of the fiber/matrix interface, and a method for examining the rate sensitivity of the tensile strength. A significant rate sensitivity was observed for glass fiber-reinforced rod but not for aramid fiber-reinforced rod. (Author)

To assure the reliability of silicon carbide and silicon nitride in turbine applications, their mechanical properties at high temperatures must be understood. Fracture properties are particularly important. Because the experimental techniques for the measurement of these properties had not yet been developed, at the start of this program, there existed little information on the fracture properties of silicon carbide and silicon nitride at high temperatures. This summary of work conducted at NBS over the past three years presents a considerable body of knowledge on these materials as a result of the improvement and development of new techniques of measurement.

Above Flight Level 290, current regulations require aircraft to be separated vertically by at least 2000 feet. Because of increased traffic desiring to fly at these altitudes, the possibility of reducing the required separation (while maintaining acceptable safety levels) is under study. This report details many of the components of vertical position error and classifies them into three major categories: static pressure system error, altimeter instrument error, and pilot response error. Two models for use in evaluating separation standards, the root sum of squares (RSS) approach and the Reich collision risk model, are described together with their respective advantages and disadvantages. A final section includes recommendations for a carefully designed data collection effort and discusses potentially important considerations for such a design. (Author)

Wear experiments have been conducted to determine the plastic strains that are introduced in the surface material near sliding wear tracks. Both oil lubricated and dry sliding experiments have been carried out at different sliding distances on surfaces of copper. The strain values were determined from selected area electron channeling patterns obtained using a scanning electron microscope from regions as small as 10 micrometers in size and 0.05 micrometer deep around the wear track. A deformed calibration specimen was used to relate electron channeling band contrast to deformation strain. Wear debris has been removed from a number of test systems and analyzed using different methods. Those methods produced specific information concerning the particulate size and composition. A magnetic debris recovery method was quantitatively evaluated using actual debris samples and also using collections of manufactured particulates having known sizes and compositions. A comparison between chemical analysis and particulate analysis findings is presented.

A formalism for computing thermodynamic properties and equilibrium compositions of reacting gas mixtures at high densities is developed. This formalism makes use of the Haar-Shenker version of the augmented hard sphere equation of state. The formalism is used for computing compressibility factors and equilibrium compositions of air in the temperature range 2,000 K - 13,000 K for densities from that appropriate to air at standard conditions (0 C, 1 atmosphere) to densities 1000 times as great. These tables are consistent with the earlier NBS tables which covered the range up to 100 times that density. Some interesting features of the dependence of composition on density are discussed. (Author)

Trends in x-ray photoelectron (XPS) spectra of chalcogens which relate to their bonding are discussed. Valence band spectra of disordered S are reported along with measurements in the same apparatus of amorphous Se and Te. Each chalcogen's spectrum has a minimum about 7 eV below E(F), between the largely p-derived states nearer E(F) and the s-derived states. The p states are split into a largely non-bonding level near E(F) and a bonding peak an energy delta E(P) below it. The splitting delta E(P) (S, 3.5 eV; Se, 2.9 eV; Te, 2.2 eV) grows with decreasing atomic number, Z, and is found to scale with Pauling's bond energies. The s states exhibit an apparent bonding-antibonding splitting which grows with decreasing Z and scales with the increasing overlap of the s orbitals. Although the s states overlap, comparisons with calculated valence levels in the free atom suggest that most of the cohesive energy in the chalcogens is gained by the bonding of the p electrons, with no major contribution from the s electron., Prepared in cooperation with Brown Univ., Providence, R. I. Dept. of Physics.

Described is the development of polymer piezoelectric devices with sufficient electrical output in response to impact to demonstrate the feasibility of using polymer elements in place of ceramic elements in ordnance fuze systems. To satisfy this requirement, piezoelectric polymer elements have been constructed capable of providing at least 0.3 mJ into a 4-ohm load, in response to a force of 89 kN (10 tonsf). Total activities of up to 360 pC/N have been achieved from elements built up from 30 sheets of 25-micrometers poly(vinylidene fluoride). Test methods developed to characterize both single-sheet and total-element activities are described, as are poling procedures and details of element construction. Mathematical analyses of polymer piezoelectric output into resistive-capacitive loads are presented for static and dynamic cases. Experimental results and theoretical predictions are shown to be in agreement to within the 10% estimate of measurement accuracy. (Author)

A program to improve the quality, reproducibility and reliability of nondestructive testing through the development of improved ASTM-type ultrasonic reference standards is described. Reference blocks of aluminum, steel, and titanium alloys are to be considered. Equipment representing the state-of-the-art in laboratory and field ultrasonic equipment was obtained and evaluated. RF and spectral data on ten sets of ultrasonic reference blocks have been taken as part of a task to quantify the variability in response from nominally identical blocks. Techniques for residual stress, preferred orientation, and micro-structural measurements were refined and are applied to a reference block rejected by the manufacturer during fabrication in order to evaluate the effect of metallurgical condition on block response. New fabrication techniques for reference blocks are discussed and ASTM activities are summarized.

On behalf of the Naval Supply Systems Command, the National Bureau of Standards was requested to assist in the evaluation of new microfilm techniques and materials which permit the adding-on of images at various times. This is an interim report on the initial evaluation of the AB Dick/Scott System 200 which uses transparent electrophotographic materials., Sponsored in part by Naval Supply Systems Command, Washington, D.C.

Three principal methods of failure prediction for brittle materials are analyzed statistically. Each method depends on fracture mechanics for its predictive value and hence, the variance of the failure time is found to depend on the scatter in the fracture mechanics data and the scatter in the estimate of the initial size of the strength limiting crack. The variance is used to calculate confidence limits for the prediction of failure for two materials, glass and silicon carbide. Procedures for the collection and analysis of data are discussed, and the implications of the analysis for lifetime prediction are evaluated.

A theory of strength loss for brittle surfaces in contact situations, developed in a previous paper for 'blunt' indenters, is here extended to the case of 'sharp' indenters. A prior fracture mechanics analysis of crack growth beneath ideal cone indenters serves as the basis for predetermining the prospective surface degradation of ceramic components in service. Compared to blunt indenters, severe degradation can occur at the lower contact loads. However, at high loads the extent of degradation becomes remarkably insensitive to indenter geometry. Essential theoretical predictions are verified by bend tests on glass slabs. The effect of indenter 'sharpness' and initial specimen surface flaw state are investigated systematically, along with some secondary rate effects in the contact process. The possibility of minimizing degradation via adjustment of material parameters (including hardness) or surface condition (e.g., residual stresses, frictional properties) is briefly discussed., See also report dated Feb 75, AD-A007 447.

This report documents exercises of the DELCAP airport simulation model performed to validate the outputs (delay and capacity) of that model. Airport throughput levels were calculated by DELCAP for five runway configurations, with three or four appropriate operating policies chosen for each, and for three different mixes of aircraft types. These estimates from DELCAP agreed well, generally within 6 to 8 percent, with current values provided by the FAA. An attempt at validating DELCAP's delay-figure output, using existing data on scheduled and actual times of aircraft departures and arrivals, is also reported. Appendices contain program listing, flowcharts, descriptions of program changes from earlier versions, and user instructions for the model's operation.

Permeability effects on the movement of sand in oscillatory flows are observed in laboratory experiments which approximate prototype conditions at the seabed under progressive waves. A natural sand is used, wave periods range between 3 and 14 seconds, and sand surfaces are naturally rippled. The apparatus has a symmetry which removes all effects, except those of permeability, which might cause a net movement of sand. Onshore and offshore directions are determined by phase relationships between the horizontal flows and superposed vertical permeability flows. A positive permeability effect is found, in that the ripple profiles move in the onshore direction. The velocity of this motion is measured and described in a simple dimensionless plot. The associated net transport of sand is not observed directly but can be inferred, to an extent, from the motions of the ripple profiles. The effects of permeability are cumulative and can be significant in coastal processes of long duration. Any estimate of the local rate of sand transport onshore due to permeability involves the distribution of permeabilities within the seabed which are largely unknown. An overall estimate is less than 1 cubic meter per meter of shoreline per year, which is negligible for most engineering considerations. (Author)

Determinations of strains have been made on the surface and subsurface on specimens of high purity iron after different amounts of sliding wear have taken place. The method involved the measurement of loss of intensity (contrast) of particular electron channeling lines obtained from small selected areas near the wear track. Through the use of a calibration specimen deformed plastically to a range of strain values, the channeling line contrast loss was related to plastic strain. Strain maps lateral to the wear track and below the original surface were obtained for different total sliding distances by removing controlled thicknesses of iron using electropolishing. In all cases the maximum strain was found at the track center location at the surface and the strains decreased steadily with depth below the track. At 50 g load the strains vanished at about 40 micrometer depth. Significant strains were found to exist outside the wear track boundaries. The results are compared with other studies previously reported.

This report summarizes the results of a program to develop optical radiation sensors for fire detection using polymeric pyroelectric sensing elements. Emphasis has been placed on techniques for constructing such devices, including methods of enhancing the pyroelectric response. Materials investigated included polyvinyl fluoride (PVF) and polyvinylidene fluoride (PVF2). Six sensors were developed and delivered to the sponsor. Highlights reported include achievement of a value of specific detectivity, D 2 x 10 to the 8th power cm. square root of Hz.1/w and the construction of a set of sensors useful over a wavelength range extending from the ultraviolet to the infrared. Methods of characterizing the performance of sensor elements are described. (Author)