bluuebunny/crossref_metadata_2025 huggingface dataset:
Friction-Induced Ignition in Oxygen
Authors: Jenny R , Wyssmann HR
Published: March 2009

The friction-induced ignition of structural materials in oxygen has been investigated. A test arrangement has been designed that allows basic data for the oxidation reaction rate to be determined for various materials or pairs of materials. The rate at which oxidation energy is released at the rubbing interface is obtained from the difference in measured friction power necessary to produce the same interface temperatures in tests with oxygen and an inert gas. These results are then correlated by the Arrhenius rate law, allowing the oxidation reaction rate factors for the different materials to be determined.

The theoretical simulation of the ignition process for the test arrangement using these data is in good agreement with the observed experimental results. This suggests that the geometry, ambient temperature, and gas velocity, which have a primary effect on heat dissipation are adequately taken into account by the theoretical model.

In addition to the collection of these basic data, the test allows materials to be classified for oxygen compatibility under friction simply by means of comparing the axial load necessary for ignition. Of the pairs of materials tested, Monel was found to give the highest ranking, followed by stainless steel/cast iron and bronze. The propagation of combustion after ignition was smallest with Monel, followed by bronze, and was largest for stainless steel/cast iron.
Selection of Metals for Gaseous Oxygen Service
Authors: Slusser JW , Miller KA
Published: March 2009

Selection of metals for gaseous oxygen service requires consideration of compatibility test data and the design of the specific component. Of the various oxygen compatibility tests, the promoted ignition test provides one of the best indications of the performance of a metal in gaseous oxygen. Promoted ignition test results for copper alloys, nickel alloys, and iron alloys are reviewed. The use of the extended fire triangle to predict the performance of a component is discussed. Materials are selected for a hypothetical control valve for 1.7 MPa (250 psi) oxygen service by considering compatibility test data and the valve design.
An Introduction to Acoustic Emission
Authors: Liptai RG , Harris DO , Tatro CA
Published: March 2009

A brief introduction to the field of acoustic emission is presented. The basic mechanisms of acoustic emission and a brief historical survey of the technology, along with some of its application to materials research and structural evaluation programs, are discussed.
Research on the Sources and Characteristics of Acoustic Emission
Authors: Schofield BH
Published: March 2009

A review of some of the less familiar acoustic emission characteristics and anomalies is presented with the objective of suggesting new or alternate approaches to better understand the phenomenon. Topical discussions include slip and twinning induced emission, acoustic responses during metal etching, residual stresses, and influence of grain size and fatigue. Specific shortcomings in acoustic emission research at present are noted as well as the need for additional research to keep up with the ever increasing and unusual practical applications.
Dislocation Motions and Acoustic Emissions
Authors: Gillis PP
Published: March 2009

The possible role of dislocations in producing acoustic emissions is discussed from a kinetic point of view. A general theory of the acoustic power of dislocation motions is developed. For deformations that tend towards homogeneity and are dependent on dislocation motions the implications of this theory are qualitatively described and shown to be corroborated by selected experimental results.
Design Criteria for Acoustic Emission Experimentation
Authors: Tatro CA
Published: March 2009

Acoustic emission experiments that can be performed in the laboratory using a single transducer and involving specimens or simple components are discussed. The emphasis is on experimental design rather than on single experiments or results produced. The experiments described are restricted to those where application of mechanical load is used to condition the material, and where commercially available equipment is adequate for instrumentation.

The magnitudes and characteristics of the acoustic emission response are described. The compromises in signal detection and data acquisition methods follow from this description. Those aspects of experimental design which are most likely to be foreign to the new user of acoustic emission techniques are pointed out, as are ways to assure that a proper design has been achieved. Results of an experiment which reveals the unique power of acoustic emission technology to reveal subtle changes in material are given as an example.
Acoustic Emission Applied Outside of the Laboratory
Authors: Hutton PH
Published: March 2009

The paper presents a cross section of beneficial applications which illustrate the wide variety of present day uses of acoustic emission surveillance. These uses range from detection of flaws in pressure vessels during hydrostatic testing to inspection of building floors for detecting weak points, detection of impending failure in localized segments of rock structure in mining, and process control in metal forming work. While these examples are not all inclusive, they do show that acoustic emission is not just a laboratory novelty and that beneficial use of the phenomenon is beginning to be realized.
Dislocation Motion As a Source of Acoustic Emission
Authors: Frederick JR , Felbeck DK
Published: March 2009

The sudden strain increment that results from the unpinning of dislocations or from the activation of dislocation sources can result in observable acoustic emission. A model has been developed that relates the amount of acoustic emission to the size of a dislocation source, the distance the dislocations slip, and to the grain size. The model is able to explain the effect of the microstructure of the metal on the amount of observed acoustic emission. Data obtained on the acoustic emission from various metals support the model. In general, the greatest amount of emission occurs during the application of stress to a test specimen and particularly during yielding. However it is also possible to obtain acoustic emission during removal of a stress in those materials that show a Bauschinger effect.
Acoustic Emission During Martensite Formation
Authors: Speich GR , Fisher RM
Published: March 2009

Martensite formation in an Fe-28Ni-0.11C alloy has been studied using acoustic emission, electrical resistivity, and quantitative metallography techniques. Comparison of these three techniques indicates that about 15 martensite plates are involved in each acoustic emission and that the volume of martensite formed per acoustic emission decreases with increasing volume fraction. The first observation is consistent with the autocatalytic effect and the second with the geometric partitioning effect which are both present in martensitic transformations. Because acoustic emission gives an almost plate by plate record of the martensitic transformation, more detailed studies of the transformation kinetics can be made with this technique than by other techniques such as dilatometry or electrical resistivity.
Observation and Analysis of Simulated Ultrasonic Acoustic Emission Waves in Plates and Complex Structures
Authors: Fowler KA , Papadakis EP
Published: March 2009

Experiments have been performed with the Panametrics acoustic emission simulation test set which show that acoustic emission signals in plates and shells travel in the plate modes supported by these shapes. The first longitudinal plate mode has the highest group velocity in its low-frequency limit, and signals in that mode and frequency range arrive first, followed by strong signal at the velocity of the first flexural mode in its nondispersive region. In some cases the flexural signal is much stronger than the longitudinal signal. In general, the received signals are dispersed. The time-frequency-energy output matrix tends to be complicated, as energy of different frequencies is spread over time by the various dispersive modes. Special transducers can be used to discriminate against certain particle motions, suppressing the reception of certain modes, and may be useful in triangulation studies.
Acoustic Emission Testing of Pressure Vessels for Petroleum Refineries and Chemical Plants
Authors: Cross NO , Loushin LL , Thompson JL
Published: March 2009

Acoustic emission testing (AET) is being used by fracture mechanics and nondestructive test engineers to establish the design adequacy, structural integrity, and operating safety of petroleum and petrochemical equipment. Used as a tool in the application of fracture mechanics concepts, AET of heavy wall pressure vessels during hydrostatic testing also provides the means of assuring against catastrophic brittle fracture by locating growing defects. The state-of-the-art in developing effective electronic instrumentation and flaw site triangulation methods has reached the point where AET should be considered competitive with other, more commonly specified test methods.

For onstream surveillance, AET has the potential for the detection of service induced flaws and for detecting potentially detrimental changes in material properties. The amplitude and frequency content of environmental noise can however, limit applications of this type. Although techniques are available for minimizing the reception of unwanted electrical and mechanical sources of noise, additional effort is needed in this area to facilitate widespread inservice use.

Other areas requiring further research and development effort and the development of standards, include flaw signature analysis, signature analysis characteristics for various materials, simplified instrumentation, acoustic parameter selection, the effect on signals of environmentally induced materials property changes, and data display.
The Broad Range Detection of Incipient Failure Using the Acoustic Emission Phenomena
Authors: Balderston HL
Published: March 2009

The broad range detection of incipient failure in structural, mechanical, hydraulic, pneumatic, electrical, and electronic systems is based upon the detection of the two basic causes of failure. These causes are structural degradation and chemical contamination occurring in the structure of the material of which the systems listed above are composed. The detection of incipient failure allows maintenance to be programmed at the convenience of the user, thus preventing down time of equipment during use periods.

The acoustic emission phenomena are employed in the detection of incipient failure in all types of equipment covered in this report. Specifically, the examples chosen are structural, mechanical, pneumatic and hydraulic components, subassemblies, or specimens as applicable. From these examples the broad range incipient failure detection concept based on the acoustic emission phenomena is developed. The experiments covered include detection of incipient failure in bearings, hydraulic assemblies, pneumatic subsystems, stress corrosion in aluminum, ductile tensile failures in carbon steel, 4330M steel, and in boron-epoxy composite material.
Round Robin Testing of Acoustic Emission Source
Authors: Brown AE , Liptai RG
Published: March 2009

The use of a martensitic phase transformation in Au-47.5 atomic percent Cd alloy as a source of acoustic emissions is discussed. The use of this source as a standard provided a means of comparing acoustic emission data from several laboratories. The results of round robin testing of this alloy at various laboratories are also presented.
Comparison of Scatter Under Program and Random Loading and Influencing Factors
Authors: Jacoby GH , Nowack H
Published: March 2009

The paper deals with the scatter under program and random loading. For the explanation of the results, constant amplitude tests and tests with biharmonic loading are also included in the study. The basis of the comparison of the data is the logarithmic normal distribution and its parameters. It was found that scatter under program, random, and biharmonic loading is identical and is similar to the scatter derived in constant amplitude tests in the life range of about 105 load cycles. This is true for life as well as for crack propagation. Miner's rule overestimates the scatter, which occurs in tests simulating irregularly varying service loads. An important influence on scatter is due to the testing machine.
Investigation of Fatigue Life and Residual Strength of Wing Panel for Reliability Purposes
Authors: Eggwertz S
Published: March 2009

In the reliability analysis for a fail-safe structure, statistical information regarding service time until fatigue crack initiation as well as subsequent reduction in residual strength is indispensable. Safety during the service life requires that critical cracks be detected at inspections before the probability of the damaged structure meeting a load exceeding its residual strength has reached an unacceptable level. About 20 sheet panels of 2024-T3 aluminum have been fatigue tested until cracks of various lengths appeared, using a flight-by-flight load program. The fatigue panels had four rows, with four small strips of the same sheet material in each row. The strips were attached to the sheet by two rivets, forming 32 stress concentrations in each panel. After fatigue cycling, the strips were replaced by continuous stringers and the residual tensile strength of the panels was determined. The mean of the logarithm of the number of flights to crack initiation amounted to 4.43, that is, 27,000 flights, while the standard deviation was 0.17. The relationship between the residual strength of the stiffened panel and the critical crack length shows rather little stochastic variation. When the residual strength is plotted versus the crack propagation time, however, the scatter does not seem to be negligible.
Random Fatigue of 2024-T3 Aluminum under Two Spectra with Identical Peak-Probability Density Functions
Authors: Linsley RC , Hillberry BM
Published: March 2009

Broad-band and bimodal spectra random fatigue tests were performed on 2024-T3 aluminum alloy specimens. The specimens were axially loaded through an electrohydraulic closed loop test system. The two spectra were produced by filtering the output of a random noise generator. These filters were adjusted to provide nearly identical ratios of the number of zero crossings with positive slope per second to the number of positive peaks per second for the two signals. There was no significant difference in mean fatigue lives of both spectra at the 0.01 significance level.
Application of Topological Concepts in Stereology
Authors: Steele JH
Published: March 2009

The quantitative characterization of microstructure involves consideration of the topological properties of the physically distinguishable 3-dimensional regions (for example, phases or grains) which constitute it. The two topological properties of primary interest are the connectivity and number of separate regions. These topological concepts, their measurement, and their application in describing sinter bodies will be discussed.

The application of topological relationships to polycrystalline microstructure is extremely important in quantitative characterization of grain shape and boundary configurations. In this case, the properties of space filling, simply connected, polyhedral regions will be utilized to develop a consistent set of equations relating the number of grains, faces, edges, and vertices to the average configurations of these features. The implications and limitations upon polycrystalline aggregates which result from these equations will be presented. The measurement of these properties and their application in describing normal grain growth will also be discussed.
Automatic Methods for Analysis of Microstructures
Authors: Moore GA
Published: March 2009

From the viewpoint of materials engineering and quality control the significant aspects of the microstructure of a material as a whole constitute a gestalt which controls mechanical behavior. This gestalt can be specified by six stereologically valid parameters measuring phase percentage, size and spacing of particles, variability among portions of the material, general anisotropy, and degree of patternness. Raster scanning devices of either the mechanical or television type are intrinsically capable of easily measuring these six parameters. Provision for each is available in at least one of the present television scanners. Minor changes are desirable to provide this common set of measurements with all instruments and to improve accuracy.

In contrast, microarchitectural processes which identify, measure, and selectively count individual object sections require massive programming effort and areinefficient and time consuming in present computers. Selective specimen preparation and human designation of objects are preferable to machine identification. Some proposals for more efficient and more human-like machines are mentioned. Materials engineers should try to avoid these difficult processes whenever feasible.
European Instruments for Quantitative Image Analysis
Authors: Exner HE
Published: March 2009

The value of quantitative structure analysis in materials testing and evaluation is briefly reviewed. Some auxiliary devices for point counting (graticule eyepieces and screens as well as stepping microscope stages) are described. Outlined are a modern electronic device which can be attached to a light microscope, a microprobe or a scanning electron microscope, and various television microscopes built in Europe. Some suggestions for the selection of instrumentation for various problems are also offered.
Correlation Between Yield Strength and Microstructure of Some Carbon Steels
Authors: Gurland J
Published: March 2009

Experimental data compiled from the literature show that the Hall-Petch equation, which describes the grain boundary strengthening in mild steels, is also applicable to particle strengthening in spheroidized or tempered carbon steels when the mean free path in different types of microstructures is used as spacing parameter. Some results on fully pearlitic steels are also considered.
Practical Applications of Quantitative Metallography
Authors: Abrams H
Published: March 2009

An improved procedure based on the intercept method of measuring the grain size of single-phase microstructures has been developed that provides a quantitative description of the grain size yet is fast. The procedure combines the statistical advantage of using large numbers with the advantage of interpreting the data as a normal distribution, as verified by the chi square test. Application of the procedure to ferritic microstructures representative of best and worst case conditions indicates that accuracies on the order of 3 percent at a 95 percent confidence level can be achieved. In addition, the procedure is sensitive enough to distinguish a randomly mixed duplex grain structure. The measurements associated with a two-phase microstructure can be more precisely quantified through determination of volume fractions using a Pp measurement based on the use of an appropriate grid network, the coefficient of variation statistic, and the Poisson distribution. The analysis is demonstrated for an a priori system for which the percent accuracy and confidence level can be specified for the volume fraction measurement simply from calculation of the average value for Pp.
Hiding Power
Authors: Mitton PB
Published: March 2009

Hiding power (HP) may be qualitatively defined as the property of a paint that enables it to obliterate beyond recognition any background over which it may be spread. Quantitatively it may be expressed as the square feet of background that may be obliterated by a gallon of paint. The values necessarily depend upon the manner and conditions of conducting the test. It is usual to apply the paint over a background of black and white squares although areas of different reflectances, such as black and gray or gray and white, have been used. It is generally agreed that complete hiding has been reached when the paint applied over the black background has a reflectance 0.98 of that applied in equal thickness over the white background. Thus, HP becomes a function of the contrast ratio (CR) of the background and of the thickness of the paint required to reduce the contrast difference to 0.02. The value 0.02 is based on the Weber-Fechner law which states that differences of less than 2 percent for moderate illumination are imperceptible to the average eye.
Mass Color and Tinting Strength
Authors: Mitton PB
Published: March 2009

The color, when viewed by reflected light, of a pigment-vehicle mixture of such thickness as to obscure completely the background is called the mass color (MC) of the pigment. Sometimes this is called mass-tone, over-tone, or self-color. MC encompasses lightness, hue, and saturation. Although generally applied to colored pigments, it may be also applied to white pigments.
Natural Resins
Authors: Sward GG
Published: March 2009

In addition to the resins traditionally known as natural resins, this chapter includes tests on rosin and lac. It does not include bitumens, which is the subject of Chapter 8.7.
Cellulosics
Authors: Sward GG
Published: March 2009

Derivatives of cellulose used in paint and related materials include the inorganic ester, the nitrate; the organic esters, the acetate, acetate-propionate, and acetatebutyrate; the ethers, methyl and ethyl, and some of their derivatives, such as the hydroxy ethyl, the hydroxypropyl ethyl, and the carboxymethyl.
Solvents
Authors: Ellis WH
Published: March 2009

A solvent may be defined as a liquid that is used to bring a solid or semisolid material into a liquid form. The ability to dissolve a material is the distinguishing characteristic of a solvent, the primary performance property. Of nearly equal importance in almost every coatings application is evaporation rate. Direct measurement of these performance properties is not always feasible or convenient. Other tests, therefore, are used to estimate them. There are other important properties, and tests to measure them, that are not concerned directly with basic performance. These include safety of handling, uniformity, purity, composition, and compliance with air pollution laws.
Abrasion Resistance
Authors: Roberts AG
Published: March 2009

The problem of resistance to abrasion exists all around us—on floors, walls, furniture, automobiles, highways, signs, military gear, spacecraft, etc. Because abrasion or wear resistance is a basic factor in the durability of a coating, its measurement is of practical importance to both producer and consumer.
Adhesion
Authors: Corcoran EM
Published: March 2009

Before one can evaluate various instruments and methods for measuring the adhesion of organic coatings, it is important to have a fundamental understanding of what measuring adhesion means in the light of modem science, since so many significant discoveries have been made within the past decade. Only after we have this understanding can we appreciate which methods are useful and which have little or no practical value. ASTM Designation D 907, Definition of Terms Relating to Adhesion, defines adhesion as “the state in which two surfaces are held together by interfacial forces which may consist of valence forces or interlocking action, or both.” If we speak of adhesion as these interfacial forces, then we must abandon hopes of trying to measure adhesion. That is, we cannot measure these interfacial forces by means of mechanical tests. However, even if we could, knowledge of the magnitude of these forces would not necessarily mean anything in a practical sense, since “adhesive” failures have invariably proven to be cohesive.
Flexibility
Authors: Schurr GG
Published: March 2009

Although the term flexibility is used frequently by the paint industry, no authoritative definition exists. Webster's first definition “capable of recovering size and shape after deformation” applies more to elasticity. A minor definition given by Webster fits paint industry usage somewhat better, “capable of being bent, turned, or twisted without being broken and with or without returning to its former shape.” L. J. Radi in his Glossary for the Protective Coatings Industry gives the following.
Tensile Strength and Elongation
Authors: Schurr GG
Published: March 2009

In Chapter 5.4 flexibility was discussed as a property of organic coatings attached to substrates. In this section tensile strength and elongation will be discussed as properties belonging to unsupported films of organic coatings. Webster defines tensile strength as “the greatest longitudinal stress a substance can bear without tearing apart” and elongation as “the total deformation in the direction of load or per unit of length caused by a tensile force or the maximum permanent stretch per unit of original length induced in a body by a force that causes it to break.” These definitions are quite adequate as a starting point to discuss the measurement of these properties for organic coatings, but they do need some interpretation.
Chemical Resistance
Authors: Boylan JA
Published: March 2009

Tests for resistance of coatings to chemicals may be relatively simple or complicated. Spot and most immersion tests are examples of the former, while procedures requiring sophisticated equipment and rigorous conditions of test can be quite complicated. Regardless of the procedure, information on details of preparation, testing, and reporting is extremely important and must be agreed upon by buyer and seller. Any change in surface appearance or condition may be considered to be a weakness and is a basis for complaint. The change is manifested by softening, swelling, discoloration, loss of gloss, loss of adhesion, or other special phenomena. In most methods these details are specified.
Cement-Base Paint and the Painting of Masonry
Authors: Nevins TE
Published: March 2009

Many studies have been conducted to investigate the nature and behavior of Portland cement, a material widely used in our society today. However, almost all relate to the engineering aspects of the material as it is used in the construction or building industry. Very little has been written about its chemistry or physics when it is used as a pigment or extender in a vehicle system such as linseed oil or a styrene-butadiene polymer solution. The properties necessary for the manufacture of a good powder “portland cement paint” for masonry surfaces are difficult to find enumerated.
Waxes and Polishes
Authors: Sward GG
Published: March 2009

The principal use of wax in paint technology is as an ingredient of polishes for floors, furniture, and automobiles, and in coatings for paper. Many natural waxes of animal, vegetable, and mineral origin are used for these purposes. Camauba, ouricuri, candelilla, beeswax, paraffin, microcrystalline, and oxidized microcrystalline predominate. The natural waxes, except the hydrocarbons of which paraffin is an example, consist of esters of the higher fatty acids, such as cerotic (C25H61COOH), and the higher monohydroxy alcohols, such as myricyl (C30H61OH). In addition there are present free fatty acids, alcohols, and small percentages of hydrocarbons. Table 8.4-1 gives the important constants of many of the natural waxes.
Putty, Glazing Compounds, Caulking Compounds, and Sealants
Authors: Sward GG
Published: March 2009

The materials listed in the title of this chapter play an extremely important role in the preservation of buildings and other structures in preventing damage by water, air, dirt, heat, and sound. They are used to seal glass in all types of sash and holding members; to join ill-fitting construction materials; and to fill openings that, because of expansion and contraction, do not lend themselves to rigid welding.
Bituminous Coatings
Authors: McCowen HH
Published: March 2009

Bituminous coatings are used on surfaces to reduce or eliminate the destructive effects of weather, chemicals, and water vapor. They are also used as sound deadeners, to provide resistance to heat transfer, and to provide abrasive coatings to minimize slip hazards. Their consistency may range from that of water to a putty-like material, or to a solid that must be heated to over 200 F (93.3 C) before they are sufficiently fluid to use.
Paint for Electrocoating
Authors: Brewer GEF , Hamilton RD
Published: March 2009

Electrocoating is painting by electrodeposition, a process that resembles electroplating.
Chemical Analysis of Pigments
Authors: Sward GG
Published: March 2009

New methods of instrumental analysis with varying degrees of automation that make use of techniques such as those described in Part 10 of this book have found rapidly increasing acceptance in analytical testing laboratories. While classic volumetric and gravimetric procedures continue to be dominant in pigment analysis, there are many areas where the newer techniques find appropriate application.
Chromatography
Authors: Esposito GG
Published: March 2009

Chromatography is a term that denotes a myriad of laboratory separation processes based on a differential migration phenomenon. It is particularly effective for the resolution of complex mixtures; hence, it can be used as a chemical preparatory method or, more importantly, as an analytical tool. This potent analytical technique has been widely used in the paint industry for a broad range of coating applications from everyday routine analysis to fundamental research into the nature of organic coating systems. Its use has been so extensive that virtually every type of material used in paint has been affected by chromatography.
Infrared Spectroscopy
Authors: Lewis WT
Published: March 2009

To understand the basic principles of the classical infrared (IR) spectrum one needs only to understand the principles of the harmonic oscillator. Certainly, to understand the origin of selection rules, quantization, etc., one will need a knowledge of quantum mechanics. However, these topics are beyond the scope of this section, and the reader is referred to several of the numerous texts on this subject [1–3].
Atomic Absorption and Flame Emission Spectroscopy
Authors: Duffer JK
Published: March 2009

Metals and metallic compounds are used extensively in the coatings industry. Pigments, extenders, and driers are just a few of the systems using metallic constituents. Many examples can be cited. Titanium dioxide is an excellent white pigment, while iron oxides provide many important coloring pigments. Some of the most vivid and attractive colors are produced by organometallic pigments. Lead octoate, manganese and lead tallates, and cobalt and iron naphthenates are used widely as driers. Phenylmercuric acetate is used frequently as a preservative in latex paints.
Mass Spectrometry
Authors: Blosser ER , Neher MB
Published: March 2009

Mass spectrometry includes a group of techniques useful in identifying elements and compounds in materials. Solids, liquids, and gases may be analyzed using the many mass spectrometers commercially available today.
Morphology and Molecular Structure of Polymers and Their Dielectric Behavior
Authors: Phillips PJ
Published: March 2009

Polymers are fundamentally covalently bonded molecules of extremely large molecular size. All of them exploit the ability of certain covalent bonds to concatenate in a stable manner. Sufficiently stable single bonds include carbon-carbon, carbon-oxygen, and silicon-oxygen. Bonds such as sulfur-sulfur and selenium-selenium, though stable at ambient temperature, destabilize at elevated temperatures. Depolymerization occurs, and the materials revert to atomic solids. Selected atoms, such as nitrogen, sulfur, and even some transition metals, may be incorporated singly into the covalently bonded polymer chain, provided they are stabilized by a neighboring link, such as a carbon-oxygen bond. In recent years more exotic polymeric systems have been produced. These include chains of alternating phosphorus-nitrogen, sulfur-nitrogen, and boron-nitrogen. All of these newer systems are based on pairs of elements which produce relatively unstable single bonds. The successful polymers contain double bonds of enhanced stability; many are oxidation resistant. Double bonding can produce special electrical properties, and the possibility exists of synthesizing polymeric materials which are intrinsically conductive or semiconductive.
Conduction Processes in Polymers
Authors: Wintle HJ
Published: March 2009

The electrical conductivity of polymers must be understood in order to improve their performance as electrical insulators. At the present time, there is a need to produce materials with lower conductivity than is currently available without compromising the desirable mechanical properties in order to satisfy the continuing demand for high-quality communications cables and optical fibers and for low-loss conventional power apparatus and cables. A further requirement will be for better standoffs for superconducting power cables. At the same time, there are other applications in which a somewhat larger conductivity would be desirable. These include the problems of static electrification of clothing, carpeting, phonograph records, and satellite antenna bushings, for which the existing palliative measures are not entirely satisfactory. Additional uses which need precise knowledge of the conduction mechanism include electrostatic recording (xerography), electrets (electroacoustic, pyroelectric, and biomedical applications), capacitor dielectrics, and films formed by glow discharge polymerization (switching devices and passivation of semiconductors). A more general background is helpful for interpreting the images obtained by scanning electron microscopy in the conduction mode.
Radiation Effects on the Electrical Properties of Solid Insulation
Authors: Campbell FJ
Published: March 2009

The primary process in the interaction of radiation with matter is the production of ions and electronically excited states of molecules, which in turn may lead to the formation of free radicals. The subsequent changes occurring in the material will be manifested in both transient and permanent effects that can be measured by suitable test procedures. The establishment of criteria for the evaluation of the radiation endurance of insulating materials is very complex, since such criteria will depend on the total environment and the application in which the materials are used.
Cyclic Stress-Strain Behavior of Two Alloys at High Temperature
Authors: Jaske CE , Mindlin H , Perrin JS
Published: March 2009

The cyclic stress-strain curve is useful in the design of structural components that are subjected to cyclic plastic deformation. Since the incremental step test has been used successfully to approximate cyclic stress-strain curves of metals at room temperature, the objective of this study is to evaluate its usefulness in describing the cyclic deformation behavior of two alloys at elevated temperature.

Constant strain rate incremental step tests were conducted on nickel-iron-chromium Alloy 800 and Type 304 austenitic stainless steel in air at temperatures between 70 and 1400 F. This experimental technique provided a useful method of determining cyclic stress-strain curves for these two alloys over that temperature range. Alloy 800 cyclically hardened by factors between 2 and 5, with a maximum amount of hardening at 1200 F. Type 304 stainless steel cyclically hardened by factors between 2 and 3, with a maximum amount of cyclic hardening at 1000 F. Strain rate and maximum strain range were shown to influence cyclic hardening of the Type 304 stainless steel at both 1000 and 1200 F. Results indicated that the cyclic stress-strain curve obtained from an incremental step test is most useful for estimating the cyclic stress-strain response of a material under variable-amplitude loading.
Effects of Temperature and Deformation Rate on Cyclic Strength and Fracture of Low-Carbon Steel
Authors: Abdel-Raouf H , Plumtree A , Topper TH
Published: March 2009

Cyclic deformation behavior and fracture mechanisms of Ferrovac E iron under low cycle fatigue conditions are studied at temperatures ranging from 23 to 540 C, cyclic deformation rates from 4 × 10-4 to 2 × 10-1 s-1, and strain ranges from 0.010 to 0.040. The stress response during strain cycling shows three stages, primary hardening, steady state behavior, and secondary hardening. Both the onset and duration of secondary hardening are dependent on deformation rate and temperature through the process of dynamic strain aging. Stress response sensitivity to deformation rate increases under conditions which permit changes in both internal and effective stress components. There is a variation in the internal stress component at the blue brittleness temperature (370 C) caused by an increase in total dislocation density due to dynamic strain aging. However, at higher temperatures (485 to 540 C) a variation in the internal stress component is caused by accelerated thermal recovery. Steady state cyclic deformation in this temperature range is observed to be consistent with models for steady state creep and hot-working. The fracture mechanism and fatigue life are mainly influenced by the characteristics of stress and strain redistribution and the inhomogeneity of plastic-strains. This inhomogeneity of deformation results from dynamic strain aging effects during fatigue. A parameter which controls stress response, fatigue behavior, and fracture mode under dynamic strain aging conditions is presented.
An Automatic Flash Photomicrographic System for Fatigue Crack Initiation Studies
Authors: Papirno R , Parker BS
Published: March 2009

An automatic system has been developed to take flash photomicrographs of the roots of notches in flat doubly-notched specimens during low cycle fatigue tests to determine the cyclic time of crack initiation. The photomicrographs are taken on 35-mm film periodically during the test at preprogrammed cyclic intervals without interrupting the cyclic loading procedure, until a well-defined crack has formed and extends across the full thickness of the specimen at the notch root. In making the data analysis, the developed negatives are projected on a screen at a magnification of approximately 100, and the final well-defined crack is traced backwards in “time”, frame by frame, to its initiation. A crack is judged to have just initiated when it is visible in one frame and not evident in the frame just preceding. Cracks with a surface length of 0.001 in. (0.025 mm) and an opening of 0.0001 in. (0.0025 mm) are easily visible in the projected images.
Crack Propagation in Notched Mild Steel Plates Subjected to Cyclic Inelastic Strains
Authors: Gowda CVB , Topper TH
Published: March 2009

Mild steel (SAE 1015) plate specimens with central circular holes were used to study crack propagation in the inelastic strain region. These thin plates were subjected to completely reversed constant amplitude cyclic strains in a servocontrolled testing machine. Fatigue crack propagation results in the inelastic strain region showed that the rate of crack growth is a polynomial function of the equivalent stress intensity factor developed in this work. The relation is similar to the equation proposed by Paris and Erdogan for an elastic case and describes crack propagation rates for both elastic and inelastic strain levels. The equivalent (or modified) stress intensity factor indirectly represents actual crack tip stresses and strains and reduces to the elastic stress intensity factor. With the aid of the results of the present study, other methods proposed by various investigators for predicting crack propagation rates are also discussed.
Cumulative Fatigue Damage Under Complex Strain Histories
Authors: Landgraf RW
Published: March 2009

The accumulation of fatigue damage under complex mechanical histories is approached from a cyclic deformation viewpoint. Smooth axial specimens of SAE 1045 steel in two heat treated conditions were subjected to repeated blocks of a variety of complex strain histories and the resulting stress-strain responses determined. A new damage equation, based on simple materials properties, was then applied to stabilized blocks and a fatigue life predicted. The method entails a reversal-by-reversal stress-strain analysis of a history using the ratio of plastic to elastic strain range as a damage parameter. A computer program was developed to perform the detailed data reduction and analysis and can be employed on-line in a computer interfaced, closed loop test system. Agreement between experimental and predicted lives is within a factor of two over the range of lives investigated.
Asphaltic Grouts, Mastics, and Cold Applied Cements
Authors: Butterfield WL , Haney FH
Published: March 2009

Bituminous grouts, mastics, and cold applied cements are all adhesive materials that vary in consistency from thin brushable or pourable liquids to trowelable in the condition in which they are applied. Grouts are thin enough to be poured, and mastics are usually of troweling consistency, whereas cold applied adhesives may be found in either consistency range.
Glass-Fiber Felt Roofing Products
Authors: Hayes JG
Published: March 2009

Glass-fiber felts permit monolithic construction in both field-assembled built-up roofs and factory-produced prepared roofing materials. Composed essentially of inert inorganic materials, these felts are not subject to deterioration and decay or attack by fungi or bacteria. Moisture absorption or migration within the felts is prevented by the noncellular structure of the glass fibers. Product appearance resembles that of paper-like felts, and methods of application are virtually the same as those for laminar-type constructions. Performance histories together with the results of controlled weather testing show that these materials and constructions perform at least as well as other designs.
The Future of Silicon X-Ray Detectors
Authors: Aitken DW , Woo E
Published: March 2009

The future potential for silicon X-ray detectors is appraised in view of recent accomplishments, present trends, and present physical knowledge. The discussion includes achievements in resolution with both small and large area detectors, and at both low and high count rates. Differences are emphasized between theoretical capability and experimental practicality, with the dual aim of helping the experimenter to evaluate the potential of silicon X-ray spectrometers in his own work, and of guiding him toward experimental design concepts that might enable him to make the maximum use of the available electronic and detector performance capabilities. The present advantages of silicon over germanium for X-ray energies below about 40 keV are discussed.
Characterization Of Semiconductor X-ray Energy Spectrometers
Authors: Walter FJ
Published: March 2009

The important performance parameters of a semiconductor X-ray energy spectrometer and the standardized techniques for measuring and documenting most of the related specifications are described.

The strong coupling between performance parameters such as energy resolution, detector size (efficiency), count-rate capability, and general spectral integrity (tailing, etc.) is detailed. In particular, the conflict between the need to improve energy resolution by increasing the amplifier shaping time constants (that is, minimizing field-effect transistor noise) and the need to improve count-rate capability by decreasing amplifier pulse shaping time constants are examined thoroughly.

Since, as is shown, most performance parameters can be improved at the expense of other characteristics, the importance of providing enough test data to determine the trade-off cost involved in optimizing a particular variable is emphasized.
Role of Multichannel Analyzer in Data Handling
Authors: Williams G
Published: March 2009

The multichannel analyzer role in X-ray spectrometer analysis has been taking on an ever increasing importance. Complete energy spectra observations are now possible from a single scan of a specimen with electron microscope.

The scope of this paper will be to interpret these spectral data in terms of accuracy, parameters, and usefulness to the X-ray spectrometer user. A set of general specifications will be outlined for the multichannel analyzer to cope with the ever changing requirements of the user and developments of the manufacturer.

With this aid it is the hope that the users of the multichannel analyzers will be able to incorporate units in their system that will perform the present and future functions of their applications.
Solid-State X-ray Detectors for Electron Microprobe Analysis
Authors: Lifshin E
Published: March 2009

Semiconducting X-ray detectors with low noise and high resolution have recently become available for the less than 20 keV range which is the region of interest encountered in the examination of X-rays produced in the electron microprobe analyzer. Although their energy resolution is generally less than that of crystal spectrometers, they offer special advantages including simultaneous collection of all detectable X-ray signals, high collection efficiencies, wavelength measurement independent of specimen position, and rapid collection of data in a form compatible with computer processing. Added to an electron microprobe, they provide a method of detecting in several minutes all elements with atomic number greater than sodium and present in quantities as small as a few tenths of a percent. Quantitative analyses are possible provided care is exercised in evaluating background spectra and peak overlap.
Energy Dispersion X-ray Analysis on the Scanning Electron Microscope
Authors: Russ JC
Published: March 2009

The scanning electron microscope is similar in many respects to the electron probe analyzer, but the scanning electron microscopist has a different goal and examines different specimens. The very low beam current of the scanning electron microscope requires the higher efficiency of the energy dispersion spectrometer (as compared to the wave-length dispersion type) resulting from a large solid angle, virtually 100 percent detection efficiency, and simultaneous analysis of all elements. Another advantage is that there is no confusion of lines due to the order of diffraction from a crystal. In examining rough surfaces or when working at low magnification, there is no loss of X-ray intensity because there is no geometric dependence of the energy dispersion detector. At high magnification the energy dispersion detector gives better X-ray resolution because of the smaller incident beam that can be used. The minimum detectable limits are comparable to wave-length spectrometers except for light elements, and quantitative analysis is practical. The modes of display include line scans and X-ray images in addition to point analyses. The paper discusses practical considerations in selecting and operating an energy dispersion X-ray system.
Results of Cooperative Test Series on Asphalts from the Zaca-Wigmore Experimental Project
Authors: Skog J
Published: March 2009

The Zaca-Wigmore Experimental Asphalt Project was constructed during 1954–1955 and involved 16 individual test sections and 10 different asphalts. During the construction of the pavement 16 individual barrel samples of asphalt were obtained. Each sample represented the asphalt placed in each test section.

The barrels were carefully heated and separated into 1-gal samples. These samples were sent to 9 laboratories for testing. Later four other laboratories also performed the required test schedule.

The values for the Pensky-Martens closed flash, Cleveland open cup flash, penetration at 77 F and 39.2 F, Saybolt Furol viscosity at 275 F, and standard loss at 325 F tests were determined in duplicate by each laboratory. Also certain of the laboratories performed the thin film test.

A statistical analysis of the results is presented together with a discussion on the influence of the source of the asphalt on the accuracy of the tests.