bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatigue Crack Growth Data for Various Materials Deduced from the Fatigue Lives of Precracked Plates
Authors: Pook LP
Published: March 2009

Data previously obtained for a wide range of metallic materials, using thin plates containing edge cracks between 0.3 and 7.5 mm (0.01 and 0.3 in.) long, have shown for both zero mean load and the general tensile stress cycle σm±σa where σm > σa that whether a crack grows or remains dormant can be predicted from the value of ΔK, the range of stress intensity factor during the fatigue cycle: a critical value ΔKc is necessary for crack growth, its value in general depends on the ratio σm/σa.

Fatigue crack growth data for many materials can conveniently be represented by the equation da/dΝ = Β(ΔK)m, where Β and m are material constants. If this equation is integrated the initial rate of crack growth can be calculated from the total fatigue life of a cracked specimen. Data for low crack growth rates, obtained in this way from the broken plate specimens, are in good agreement with data obtained from conventional crack growth tests. The method has the advantage that no crack growth monitoring instrumentation is necessary, so that data on crack growth in difficult environments can readily be obtained.
Fatigue Crack Propagation Growth Rates under a Wide Variation of ΔK for an ASTM A517 Grade F (T-1) Steel
Authors: Bucci RJ , Clark WG , Paris PC
Published: March 2009

Fatigue crack propagation experiments on an ASTM A517 Grade F (T-1) steel were carried out within the framework of linear-elastic fracture mechanics.

At low ΔK levels an examination of very slow fatigue crack propagation rates of the order of 10-9 in./cycle revealed the existence of a stress intensity threshold level, ΔKT, below which fatigue crack propagation rates become diminishingly small (order of 10-9 in./cycle). Stress ratio, R (ratio of σmin/σmax ≃ Kmin/Kmax), was found to alter the threshold ΔKT with higher R ratios resulting in somewhat depressed threshold values. The influence of stress ratio was also felt at ΔK levels above the threshold with increased growth rate being associated with increased values of R.

Low ΔK level fatigue crack growth rate tests were conducted at room temperature in air, distilled water, and dry hydrogen gas. These environments did not effect the fatigue threshold. Identical values of ΔKT were recorded in each environment studied. Furthermore, for the range of slow growth rates, order of 10-9 to 10-7 in./cycle, and frequencies, 120 to 180 Hz, considered, these environments seemed to produce little effect on fatigue crack growth rate results.

For higher cyclic growth rates (> 10-7 in./cycle) and ΔK levels, the effect of material condition and heat treatment was evaluated. Plate material rated as ultrasonically good and poor was evaluated in two heat treated conditions. Examination of fatigue crack growth rates indicated that ultrasonic ratings do not necessarily give good indications of crack growth resistance.
Odor and Taste
Authors: McNamara BP , Danker WH
Published: March 2009

Odor stimuli affect only a small area of yellow brown receptor cells located in the ceiling of the inner nose. This area contains millions of nerve endings of the olfactory nerves [1]. Each nerve ending, in turn, has at its tip several fine cilia-like hairs, which are thought to contain the ultimate olfactory receptors [2]. These hairs protrude into the mucous layer which is continuous with that lining the entire surface of the inner nose. The olfactory nerves transmit impulses to the olfactory bulb located at the front and the base of the brain. At the bulb, fibers from the nose contact other nerves which go to different parts of the brain (see Fig. 1).
Predictive Testing in Elevated Temperature Fatigue and Creep: Status and Problems
Authors: Coffin LF , Goldhoff RM
Published: March 2009

The paper selects two well recognized problem areas of high temperature material behavior, namely, creep and fatigue, and considers those factors which contribute to the prediction of the useful service life of the component. The information available is obtained almost entirely in a laboratory environment, in which simplified load conditions and specimen geometries and controlled environments are employed for material evaluation. We do not consider transferring this information to actual design, other than to identify the importance of such problems as the analytical determination of stresses and strains in the structure, the effect of highly complex loading, or the behavior in a complex environment, but we will draw on several practical problems occurring in high temperature power generating machinery as examples of the topics we wish to discuss namely, creep, fatigue, and creep-fatigue interaction.

The topics of creep and fatigue are considered separately, the discussion being built around three central topics: (1) real problems in prediction, (2) complicating instabilities including the effects of environment, deformation, and microstructure; and (3) some current predictive methods. Consideration of the less well defined problem of creep-fatigue interactions is also included.
Applications of Exoelectron Emission to Nondestructive Evaluation of Alloying, Crack Growth, Fatigue, Annealing, and Grinding Processes
Authors: Hoenig SA , Savitz CA , Ott WA , Russel TA , Ali MT
Published: March 2009

It has been demonstrated that exoelectron emission phenomena can be used to observe and measure alloying, crack growth, fatigue, annealing, and grinding processes. For observation of alloying, crack growth, annealing, and grinding a fixed plate or wire collector biased at +90 V is used to collect the electrons. The current is measured by a picoammeter and recorded directly via a strip chart recorder. To find the fatigued area in a specimen a heat source is scanned along the coupon and the exoelectron emission is picked up by a moving collector wire connected to a picoammeter.

These experiments are usually done in ambient air without any special control of temperature and humidity. The initiation of crack growth is observed as a sudden change in exoelectron emission level. In a fatigued but uncracked specimen a significant increase in exoelectron emission is observed when the heat source and collector move over the area where the fatigue damage is most intense.

Most of the data to date has been obtained with aluminum but we feel that this technique can be extended to other aircraft structural materials.
A Preface to the Problem of Stress Corrosion Cracking
Authors: Brown BF
Published: March 2009

The characteristics of stress corrosion cracking (SCC) are enumerated in the context of a historical sketch of the problem. The roles of pitting and brittle fracture in affecting the behavior of materials in tests of smooth specimens are depicted. The rationale for using fracture mechanics in evaluating crack propagation behavior is given, and a rudimentary composite of the results of smooth specimen tests and crack propagation (“fracture mechanics”) specimen tests is presented. We lack predictive capability with respect to SCC from one chemical environment to another.
Stress Corrosion Cracking Behavior of Nickel and Nickel Alloys
Authors: Boyd WK , Berry WE
Published: March 2009

This paper presents a discussion of the susceptibility to stress corrosion cracking of nickel and alloys containing substantial additions of nickel. The occurrence of cracking in various environments such as chloride solutions and salt environments, hydrofluoric and hydrofluorosilicic acid, high temperature water and steam, caustic solution, mercury, mercuric salts and liquid metal embrittlement are discussed. Also discussed are the mechanism of stress corrosion cracking and the prevention of stress corrosion cracking in nickel alloys.
Testing Methods for Stress Corrosion Cracking
Authors: Ketcham SJ
Published: March 2009

Stress corrosion testing methods are discussed from a general point of view with an emphasis on the desirability of standardization. The usefulness of smooth, notched, or precracked specimens is compared and some results using the different types are presented. Some precautions that should be taken are described: these include avoidance of crevice corrosion, galvanic effects, or hydrogen embrittlement results. Finally, since it is possible to find some type of environment that will crack almost every engineering alloy, it is important to use realistic loading methods and test media that relate to material serviceability for a particular application.

The work of ASTM Committee G-1 on Corrosion of Metals in preparing recommended practices for various test specimens such as C-ring, bent beam, tension, U-bend, and precracked specimens is summarized; as is, similar work with environments such as the boiling MgCl2 test.
The Resistance of Wrought High Strength Aluminum Alloys to Stress Corrosion Cracking
Authors: Brown RH , Sprowls DO , Shumaker MB
Published: March 2009

An up to date review of the stress corrosion cracking performance of wrought high strength aluminum alloys is presented. Special emphasis is placed on factors of microstructure and its directionality and the effect of ancillary alloying elements, and environmental factors.

Examples of typical service problems encountered with stress corrosion cracking of high strength aluminum alloys are described along with means of combating them, such as peening, coatings, or the use of special stress corrosion resistant alloys.
ASTM G 63: A Milestone in a 60-Year Safety Effort
Authors: Neary RM
Published: March 2009

The author draws on his 30 years in oxygen safety and participation in the organizing task group of ASTM Committee G-4 on Compatibility and Sensitivity of Materials in Oxygen-Enriched Atmospheres and G-4 activities to review key industry and G-4 past actions relating to the selection of materials for oxygen and oxygen-enriched service. The Compressed Gas Manufacturers Association formed an Oxygen Regulator Research Committee in 1921. Sixty years later, the ASTM Guide for Evaluating Materials for Oxygen Service (G 63), the industry's first such guide, was published. Committee G-4 formation, membership, scope, and accomplishments to date, including test procedures, are reviewed. Tests currently used by several organizations are included. Future plans of Committee G-4 and its subcommittees are outlined. The standardization of test methods and guidelines for selecting materials will improve oxygen safety and benefit large and small organizations. Furthermore, it is anticipated that these ASTM standards will gradually be included by reference in future government regulations and association standards relating to oxygen safety.
NASA Mechanical Impact Testing in High-Pressure Oxygen
Authors: Bryan CJ
Published: March 2009

Many materials will ignite or initiate high energy reactions when in contact with gaseous oxygen (GOX) or liquid oxygen (LOX) if subjected to stimuli such as a mechanical impact, adiabatic compression (pneumatic impact), or an electrical discharge in the form of a spark. Such materials must therefore be characterized as to compatibility with LOX or GOX to define the degree of hazard with their use.

Generally, materials are more sensitive to mechanical impact in gaseous oxygen than in liquid oxygen, and impact sensitivity is known to increase with increasing pressure. Thus, the evaluation of the sensitivity of materials in GOX is required to supplement LOX impact test data.

Three independently developed high-pressure GOX mechanical impact testers have been used to evaluate materials for the space shuttle program. This paper presents a description of a test program evaluating the performance of these three high-pressure oxygen mechanical impact test systems. Two of the systems were fabricated from the same design drawing, whereas the third system, even though similar, was of different design. Four unpressurized mechanical LOX impact testers were also evaluated.

The most suitable materials identified were Teflon® TFE for gaskets and seals, Krytox® 240AC grease as a lubricant, and the fluorocarbon elastomers where a rubber is absolutely necessary.
Determination of Autogenous Ignition Temperatures of a Steam Turbine Lubricating Oil in Nitrogen and Oxygen Mixtures
Authors: McQuaid RW , DG Sheets , MJ Bieberich
Published: March 2009

The autogenous ignition temperature (AIT) of an MS 2190 TEP petroleum steam turbine lubricating oil was measured in oxygen-nitrogen atmospheres ranging from 20 ppm to 100% oxygen. The measurements were performed in the David Taylor Naval Ship Research and Development Center (DTNSRDC) high-pressure AIT apparatus at pressures from 0.1 to 20.6 MPa (15 to 3000 psi). The results showed hot ignition occurring with an accompanying sharp temperature rise at oxygen contents as low as 2% (by volume) in nitrogen at 10.3 MPa (1500 psi) pressure. Oxidation of the oil, as evidenced by the formation of carbon, blackened sludge, and water vapor, occurred with oxygen contents as low as 0.11% at pressures of 10.3 to 20.6 MPa (1500 to 3000 psi). A very pure nitrogen atmosphere containing only 20 ppm oxygen showed no effects on the oil sample at temperatures up to 315°C (600°F) at pressures of 10.3 to 20.6 MPa (1500 to 3000 psi), indicating that thermal decomposition was not the sludge-forming process. The DTNSRDC high-pressure AIT apparatus did not give satisfactory results below 1.0 MPa (150 psi) except in 100% oxygen atmospheres, where it gave a measurable AIT at 0.1 MPa (15 psi). The effect of the presence of various metals and oxides on the AIT of the oil was measured in 100% oxygen at 10.3 MPa (1500 psi).
Oxygen Index Tests to Evaluate the Suitability of a Given Material for Oxygen Service
Authors: Ikeda GK
Published: March 2009

The oxygen index of a material, described in ASTM's Measuring the Minimum Oxygen Concentration to Support Candle-Like Combustion of Plastics (Oxygen Index) (D 2863), is the percentage concentration of oxygen in a mixture of oxygen and nitrogen that will maintain equilibrium burning conditions. It is a numerical measure that can be accurately reproduced with inexpensive test equipment and simple procedures, and it has been used as one criterion for determining the acceptability of materials for use in oxygen-enriched atmospheres. This paper discusses the advantages and the shortcomings of the oxygen index, comparing test results to data from heat-of-combustion and autoignition temperature tests.
Measurement of Oxygen Index at Elevated Pressures
Authors: Benning MA
Published: March 2009

The oxygen index is established by ASTM as a standard measurement for the comparison of the flammability of plastics in Measuring the Minimum Oxygen Concentration to Support Candle-Like Combustion of Plastics (D 2863). The index is measured at atmospheric pressure. Measurements of oxygen index and burning rate at absolute pressures to 2 MPa (20 atm) have been made at 25°C for six materials: polytetrafluoroethylene, Viton®, neoprene, nylon, glass-filled nylon, and polymethylmethacrylate. The oxygen index was found to decrease with increasing pressure but to be independent of Reynolds number up to 1500. At the oxygen index, the burning rate was found to be independent of pressure. The data are correlated by a model that defines the oxygen index as a point of constant oxygen diffusion rate. It is concluded that with the exception of nylon, the ranking of materials for oxygen service at elevated pressures by their atmospheric pressure oxygen index is not changed. The index for nylon ranks it on the high side because, at lower pressures, hot liquid is lost from the test specimen and does not burn.
Oil Film Hazards in Oxygen Systems
Authors: Werley BL
Published: March 2009

A number of known or assumed hazard mechanisms for oil films in oxygen systems are itemized. Each mechanism is discussed for understanding in terms of its hazard and pertinent data available from the literature and laboratory tests at Air Products and Chemicals, Inc. The methods of collection, values, and shortcomings of these available data are reviewed to place the various hazards in perspective. Areas not fully understood and in need of further work or that require specific evaluation procedures are itemized.

The principal oil film hazard in oxygen systems is flammability. However, an indirect hazard is migration of nonflammable films and accumulation to flammable levels. Generally, flammability of oil films has not been reported below roughly 0.108 to 1.08 g/m2 (10 to 100 mg/ft2) film concentrations. In comparison, migration of films of thickness above roughly 0.215 to 0.431 g/m2 (20 to 40 mg/ft2) can be substantial, while films of thickness below this range migrate more slowly. Migration along a surface can be greatly inhibited by choice of surface finish. Vapor phase migration is complex. Traditional cleaning methods provide systems of cleanliness well below flammable thresholds. However, migration of oil films can eventually produce hazardous regions, and, in combination with the rate of introduction of new contaminants, dictates required cleaning intervals.
Metal Combustion in High-Pressure Flowing Oxygen
Authors: Monroe RW , Bates CE , Pears CD
Published: March 2009

The possibility of an ignition event leading to component combustion is a significant consideration in the design and operation of all oxygen production and handling systems. Most materials of construction can react violently with oxygen if ignition occurs. This paper discusses some of the current concepts of ignition and combustion of metals and presents combustion data on several metals. The materials examined were selected based on prior use in oxygen systems and anticipated combustion behavior. The observed combustion behavior is discussed in light of current theories about combustion. The materials examined were aluminum (intercoolers, evaporators, tanks, pump casings), tin babbitt (labyrinth seals), carbon steel (tanks, pipelines, compressor casings), 90–10 cupro-nickel (heat exchangers, intercoolers), and silver (labyrinth seals).
Acoustic Emission Testing and Microcracking Processes
Authors: Tetelman AS , Chow R
Published: March 2009

The various stages of microcrack initiation, microcrack growth, and final fracture are reviewed and the relation between their processes and acoustic emission is discussed. A theoretical model relating acoustic emission to the microcrack density of low carbon steel is presented, based upon experimental results of the microcrack density in low carbon iron. The model predicts that the total number of acoustic emissions increases rapidly with applied stress, above a threshold value.
Application of Acoustic Emission Techniques to Rock Mechanics Research
Authors: Hardy HR
Published: March 2009

Presented is a comprehensive review of the applications of acoustic emission in the field of rock mechanics. Acoustic emission experiments in rock mechanics were initiated in North America in the late 1930s as part of a study by the U. S. Bureau of Mines into problems associated with mine design and alleviation of rock bursts. More recently acoustic emission techniques had been employed to an increasing degree for the laboratory study of basic deformation and failure mechanisms in geologic materials. This paper outlines the major rock mechanics areas where acoustic emission techniques are being applied, and includes a brief description of a number of basic and applied studies.
Factors Affecting Acoustic Emission Response From Materials
Authors: Dunegan HL , Green AT
Published: March 2009

This paper presents selected examples of the acoustic emission response from widely differing materials with varied mechanical history, heat treatment, and state of stress. It presents the case that there is a need for characterization of the acoustic emission response of materials prior to application of the techniques for determining structural integrity so that all parameters are represented under similar conditions.
Amplitude Distribution of Acoustic Emission Signals
Authors: Nakamura Y , Veach CL , McCauley BO
Published: March 2009

Acoustic emission signals from slowly growing cracks have been studied experimentally using precracked compact tension specimens of D6ac steel heat treated to several different fracture toughness values but with the same yield strength. The observed signal amplitude is distributed over a range of more than 60 dB, reflecting the statistical nature of the fracture process in a microscopically heterogeneous medium. A clear correlation between the crack growth behavior and the emission amplitude distribution is found. A shift in the amplitude distribution with stress intensity level at a crack tip and a definite difference between the amplitude distribution of emission signals and that of rubbing noise may have direct bearing on the application of the acoustic emission technique as a nondestructive inspection method for materials as well as structural tests.
Detection of Fiber Cracking By Acoustic Emission
Authors: Harris DO , Tetelman AS , Darwish FA
Published: March 2009

A theoretical model is presented that relates acoustic emission to fiber cracking which occurs during a rising load tension test on a fiber reinforced composite. The percentage of broken fibers in an Al3Ni fiber reinforced aluminum was measured as a function of tensile strain by optical inspection of the polished surface of strained specimens. This information was used in conjunction with the proposed model to predict the acoustic emission response of the composite material. These predictions were compared with experimental observations, and a good agreement was obtained between the two sets of results. These results indicate that it is possible to relate acoustic emission quantitatively to the micromechanics of the deformation processes occurring within fiber reinforced composites, thereby demonstrating the applicability of acoustic emission to materials studies and also to nondestructive evaluation of the integrity of composite materials.
Estimating the Median Fatigue Limit for Very Small Up-and-Down Quantal Response Tests and for S-N Data with Runouts
Authors: Little RE
Published: March 2009

Much basic fatigue data may be categorized for analytical purposes as small sample quantal response data. For example, both small sample up-and-down test outcomes and most S-N data fall into this category. But reliable median fatigue-limit estimates for small samples are not directly available using large sample statistical formulas. Rather, small sample estimates must be examined carefully regarding both their variability under repeated sampling and their “sensitivity” relative to various analytical methods and assumptions. The variability of small sample response estimates has been studied by Dixon and others. This paper considers the sensitivity of these estimates to such key assumption alternatives as, for example, minimum chi square analysis versus maximum likelihood analysis, and an underlying extreme value (smallest) response distribution versus a normal response distribution. Engineering assessment of the “accuracy” of the estimated median fatigue limit requires careful consideration of both its statistical variability and its analytical sensitivity as established herein.
Regression Models for the Effect of Stress Ratio on Fatigue Crack Growth Rate
Authors: Mukherjee B , Burns DJ
Published: March 2009

Regression models, based on linear elastic fracture mechanics, are used to interpret the effect of stress ratio on fatigue crack growth rate in 7075-T6 aluminum alloy. It is shown that fatigue crack growth rate can be related to range and maximum values of stress-intensity factor. Statistical techniques are used to examine the error which may accumulate when regression equations are used to predict crack growth versus cycles curves.
A Reliability Approach to the Fatigue of Structures
Authors: Payne AO
Published: March 2009

In recent years, due to the progressive development of higher performance aircraft, the fatigue strength of aircraft structures has become an increasingly important problem.

In the present paper, a method of assessing structural safety in fatigue is proposed in which a statistical model for the fatigue process is used to carry out a reliability analysis, enabling the probability of failure to be estimated at any stage of the life. The statistical variability in crack-propagation rate and residual strength of the cracked structure is included together with the effect of any prescribed inspection procedure.

The method is applied to a structure of high strength steel typifying a “safe-life” structure and to a redundant aluminum alloy structure representative of the “fail-safe” construction.

It is concluded that the reliability analysis can be applied to both fail-safe and safe-life structures and provides a quantitative basis for ensuring their safe operation, including the planning of an inspection procedure if feasible. In this regard the method represents an advance on the existing procedures but inherent in the quantitative approach it employs is the adoption of an acceptable safety level. The most appropriate way of defining safety level is discussed and a suitable measure is proposed. An extensive amount of data is required in applying the procedure but it is suggested that in the case of aircraft structures this difficulty can be overcome by using results from the comprehensive structural testing program normally carried out, together with relevant data from similar structures.
On the Probabilistic Determination of Scatter Factors using Miner's Rule in Fatigue Life Studies
Authors: Saunders SC
Published: March 2009

A particular two-parameter family of life-length distributions for fatigue life is assumed. This family, first formulated by Freudenthal and Shinozuka in 1961, was systematically examined by Birnbaum and Saunders in 1968 where it was derived, using considerations from renewal theory, for the number of cycles needed to force a fatigue-crack extension to exceed a critical value. By employing this new family, tolerance bounds are obtained for the population of life times until fatigue failure under a programmed load. This is accomplished by utilizing a generalization of Miner's rule which computes the mean life under the programmed load in terms of the mean lives under simpler programmed loads at stress levels for which data are available. Such bounds have never been obtained previously for any other life-length distribution and the confidence level exactly determined. This paper concludes with an application of these results to a set of real fatigue data.
The Mathematical Foundations of Quantitative Stereology
Authors: Underwood EE
Published: March 2009

Quantitative stereology is the generalized body of methods, applicable to any material, for the quantitative characterization of three-dimensional microstructures by means of two-dimensional sections through the solid or projections to a plane. We deal here with the mathematical aspects of the relationships linking the two-dimensional section (or projection) to the microstructural features in the three-dimensional material. Thus, one must consider the metric relationships as well as the geometrical and topological properties of microstructures in order to completely characterize a material. Topics selected for discussion include geometrical probabilities, particle characteristics and size distributions, curvature, topological relationships, and projected images.
Quantitative Metallography of the Age Hardening Precipitate in Superalloys by Replica Electron Microscopy
Authors: Seher RJ , James HM , Maniar GN
Published: March 2009

The application of two quantitative techniques to the measurement of gamma prime size, interparticle spacing, and volume fraction in two commercial heat resistant alloys is discussed. The two methods involve the use of structure and extraction replica electron microscopy and were evaluated for their ease of application and consistency of data using various measuring parameters.
Drying Oils
Authors: Gallagher EC
Published: March 2009

Drying oils include the more or less unsaturated glycerides of long chain fatty acids. All except fish oil are of vegetable origin. Examination of the oils is mainly for quality, although adulteration as low as 5 percent may be sometimes detected. Most of the tests are chemical. A few are based on absorption in the ultraviolet portion of the spectrum (see 10.3). However, the most promising tools for better methods are probably infrared absorption (see 10.4) and chromatographic separations (see 10.2).
Pigments
Authors: Spengeman WF
Published: March 2009

Pigments are the fine, particulate solids, substantially insoluble in paint vehicles, used to impart certain properties to paint such as color, opacity, corrosion inhibition, mold resistance, viscosity, and durability. The chemical composition, physical form, and optical character of pigments vary widely. Consequently, knowledge of these characteristics is of great assistance in testing and analytical evaluation. To broaden this understanding, the nature of pigments will be reviewed briefly in each of the following major classes.
Surface Energetics
Authors: Gans DM
Published: March 2009

The creation of more surface, as in the atomization of a liquid, requires an investment of energy. Part of this energy goes into the surface as free energy and is supplied by the mechanical agent creating the surface. The rest is contributed by the environment, generally as the heat influx required to maintain the experiment at its initial temperature, since surface formation causes a temperature drop.
Preparation of Films for Test
Authors: Grenko C
Published: March 2009

Dependable testing of films of coatings requires rigorous control of film thickness. Many methods and devices for achieving this have been developed. Practically all methods of factory and field application of coatings have been adapted for small scale application in the laboratory.
Measurement of Film Thickness
Authors: Sward GG
Published: March 2009

Control of film thickness is an important part of paint testing. Film thickness measurements are a check on other associated tests in the laboratory, on the skill and will of the journeyman painter, and on the performance of automatic painting machinery.
Hardness and Related Properties
Authors: Corcoran EM
Published: March 2009

Before it is possible to arrive at a definition of hardness, one must realize that hardness is conceptual. It means different things to different people and is measured in different ways. Dealing with the hardness of relatively thin organic finishes over various substrates presents other complications not experienced when one deals with materials in bulk. That is, the apparent or measured value of hardness is dependent on factors outside of the organic finish itself. Included among these factors are the thickness of the organic finish and the nature of the substrate. Another way of expressing this is to say that hardness is not an absolute or intrinsic material property of organic finishes. It is not an absolutely definable value such as mass, length, velocity, etc. It is descriptive of many things and is variable. Trying to limit the hardness of organic finishes to a particular, intrinsic material property, is like trying to confine mercury in one's fist.
Resistance to Water Vapor and Liquid in the Atmosphere
Authors: Grossman GW
Published: March 2009

“Water, in one way or another, is the common enemy to most materials of construction. With some exceptions, protective coatings are designed to control the action of water. The corrosion of metals, the deterioration of cellulosics, the disintegration of siliceous structures, and the decomposition of organics all involve some interaction of water whether as a vapor, liquid, or solution. Protective coatings function basically by providing a barrier between an impermanent substrate and an aqueous environment” [1].
Biological Deterioration of Paints and Paint Films
Authors: Ross RT
Published: March 2009

Micro- and macroorganisms can destroy both the decorative properties and durabilities of paint films, Figs. 6.4-1 and 6.4.2. Biodeterioration of paint falls into two general categories: enzymatic degradation of protein and cellulosic thickeners that produces an irreversible viscosity loss in latex emulsion paints while still in the container, and microbial disfigurement and deterioration of both water-thinned and solvent-thinned paint films. Enzymes catalyzing the degradation of protein and cellulosic thickeners may be introduced into the paint through contaminated raw materials, storage tanks, and other equipment or be released by bacteria (and less frequently, yeast) growing actively in the liquid paint.
Natural Weathering
Authors: Garlock NB , Sward GG
Published: March 2009

The final test of a paint is its performance under actual conditions of use. For exterior paints, this means on the walls of buildings, railway cars, highway vehicles, ships, and the like. Such tests are expensive and time consuming. Hence, there has developed the practice of conducting tests on a small scale. These screening tests allow studies of the effects of many variables to be made in a fraction of the time and at a fraction of the cost of full scale tests. For final judgment, full scale tests must usually be made.
Architectural Paint
Authors: Sward GG
Published: March 2009

Architectural paints treated in this chapter include solvent-thinned and waterthinned and exterior and interior types. Cement-base paint is treated separately, even though it contains water.
Tile-Like Coatings and Seamless Floor Testing
Authors: Evans RM , Bieneman RA
Published: March 2009

Tile-like coatings (TLC) were first used in food processing plants, but their use spread rapidly to hospitals, schools, and other places where sanitation is improved by jointless walls, or where thicker coatings are needed to withstand mechanical damage. In 1963, Subcommittee 48 on Tile-Like Coatings of ASTM Committee D-1 on Paint, Varnish, Lacquer, and Related Products defined them as “systems applied by conventional means and intended to produce vitreous (tile-like) finishes on relatively rough masonry or other cementitious walls and ceilings. They are generally thicker, harder, and more washable than conventional paints.”
Traffic Paint
Authors: Sward GG
Published: March 2009

Traffic paint is an important factor in the control of traffic, not only of motor vehicles but also of aircraft at airports and of pedestrian traffic.
Printing Ink
Authors: Ray CT
Published: March 2009

Printing ink is an intimate mixture of pigments, varnishes, driers, solvents, and quite frequently, waxy and greasy compounds. Occasionally, inks also contain small amounts of special additives such as flow agents, plasticizers, antioxidants, deodorants, and perfume oils, particularly when it is desired to impart special characteristics to the ink. This definition at best is only a generalization and needs considerable amplification before it has any practical value. A printing ink must have the proper viscosity, length, flow, and tack in order to be suitable for the particular press or printing process on which it is to be used. In addition, the substrate on which the ink is to be printed dictates in a large measure the characteristics of the ink. It is essential that inks designed for different processes possess different physical characteristics in order to ensure proper distribution on the roller system of the various presses and proper transfer therefrom to the plate or type and then to the paper or other substrate. The ink must print sharply and give legible prints of the desired color. It must also dry fast enough to permit handling without offsetting or smudging.
Ultraviolet Spectroscopy
Authors: Lewis WT
Published: March 2009

Investigation into many branches of chemistry and physics reUes extensively on the analysis of absorption spectra in the ultraviolet region (200 to 400 μm). The analysis of the ultraviolet (UV) spectrum depends explicitly on the needs of the investigator. To understand the theoretical approach to analyzing a UV spectrum one needs background in the fundamentals of mathematics, physics, and chemistry. However, the purpose of this section is to consider only the practical approach to UV spectrophotometry. The reader is referred to several of the numerous theoretical treatises on this subject [1–4].
Constant-Current Coulometry
Authors: Berger HW
Published: March 2009

Faraday's law states that the total amount of chemical change occurring at the electrodes of a chemical cell is related to the total amount of electricity passed through the cell. If, under the proper conditions, 96,496 C of electricity are passed across two electrodes immersed in a conducting solution, electrolysis will take place to the extent that one equivalent of chemical change will occur. Since the coulomb is defined as one ampere second, the measurement of chemical change can be achieved by the measurement of electrical current and time. This principle is the basis of the electroanalytical technique called coulometry.
Differential Thermal Analysis
Authors: Berger HW
Published: March 2009

Differential thermal analysis (DTA) is an instrumental technique used for studying the physical and chemical changes that occur in materials as they are heated or cooled. When a material undergoes a physical change, such as melting or crystalline transformation, or when a chemical reaction occurs, energy is either absorbed or given up. If energy is absorbed the temperature of the material increases. If energy is liberated the temperature decreases.
Nuclear Magnetic Resonance Spectroscopy
Authors: Afremow LC
Published: March 2009

The first observations of the nuclear magnetic resonance (NMR) phenomena were reported in 1946 by Purcell [1] at Harvard University and by Bloch [2] at Stanford University. Since that time, NMR spectroscopy has experienced a remarkable growth and is presently one of the most useful instrumental techniques for the Study of chemical systems. During 1967 more than 2500 papers were published relating to some phase of NMR. Unfortunately, very little work has been done in NMR spectroscopy in relation to coatings chemistry. This is probably due to two major factors. The first of these is the high cost of the instrumentation involved, usually more than $30,000, and the second factor is a lack of knowledge of this technique by most coatings chemists. In regard to cost, as many coatings companies are finding out, the instrumentation will certainly pay for itself in a short time. A lack of knowledge of this technique by most coatings chemists was the inspiration for this chapter.
Treeing in Solid Organic Dielectric Materials
Authors: Eichhorn RM
Published: March 2009

Treeing is an electrical prebreakdown phenomenon. The term is applied to that type of damage which progresses through a dielectric section under electrical stress so that, if visible, its path resembles the form of a tree [1]. After initiation at a point of high and divergent electric stress, treeing can progress in dry dielectrics by periodic partial discharge; this is called electrical treeing. It may start and progress more slowly at lower electric stress in the presence of moisture without a detectable partial discharge; this is called water treeing. Treeing may also occur rapidly as the result of an impulse voltage. Trees which start to grow from within the insulation and progress symmetrically outward, parallel to the electric stress, toward both electrodes are called bow-tie trees because of their appearance. Electric stress and stress concentration are always required. Treeing has been observed to occur in all solid organic dielectrics tested and was observed in paper/oil insulation systems many years ago. Treeing may or may not be followed by complete electrical breakdown of the dielectric section in which it occurs, but in solid extruded dielectrics it is the most likely mechanism of electrical failures which do not occur promptly but rather appear to be the result of an aging process.
Breakdown Strength of Solids
Authors: Nelson JK
Published: March 2009

Solid dielectrics are universally employed throughout the electrical industry as both insulators and charge storage media. Although much research on dielectrics has been aimed at improving insulation for high-voltage equipment in the power industry, there are numerous other applications for which a fundamental understanding of the mechanisms of conduction and breakdown are imperative to allow informed design of equipment. The failure mode of thin, inorganic films such as silicon dioxide (SiO2) used as insulators in the microelectronics industry is a good example [1,2]. The development of dielectric materials themselves also relies on an understanding of the way they behave in electric fields. The large-scale acceptance of polymeric materials for insulating duties has come about, in part, as the result of the ability of the polymer industry to tailor and process materials to the needs of electrical applications.
Composite Insulating Materials and Systems
Authors: Dakin TW
Published: March 2009

Composite insulating materials are at least an order of magnitude more diverse and perhaps as much more complex in their behavior than simple one-component materials. This makes the preparation of a one-chapter summary of their electrical properties perhaps more difficult but, on second thought, somewhat simpler. This seeming contradiction can be explained as follows: the number of combinations of individual materials that have actually been used in composite insulation, and are not just possible to use, is so vast as to defy the compilation of their properties. Therefore, after considerable pondering of the task, the author has avoided that approach and is concentrating in this chapter on presenting an analytic discussion of the factors influencing the dielectric properties of composites and their performance as electrical insulation. The chapter will also include a summary discussion of the various types of composites, with representative data on their properties and characteristic behavior. We shall not delve into the molecular structure of the individual materials comprising the composites, as that aspect has already been extensively treated in Chapters 1, 2, and 6 of this volume. The testing methods that are uniquely appropriate to these materials and systems will be indicated.
Intergranular Fatigue Fracture of Chemical Lead at Room Temperature
Authors: Kitagawa M
Published: March 2009

Intergranular fatigue fracture was investigated by performing a series of torsional reversed creep and fatigue tests on tubular specimens of chemical lead at room temperature.

It is shown that the intergranular fatigue life, 2Nfgb, is related to the amount of grain-boundary sliding per reversal, ΔUgb, by a simple expression 2NfgbΔUgb=constant This simple relationship is valid for all cyclic test results in this investigation regardless of stress amplitude and strain rate.

A“strain rate modified strain range” parameter is found to be useful for describing the strain rate dependence of the intergranular fatigue fracture.
Cyclic Deformation and Failure of Polymers
Authors: Johnson TA
Published: March 2009

The phenomenological fatigue behavior of many metals can be described by equations in which the material constants are determined from cyclic deformation and monotonic fracture properties. This approach makes it possible to describe and predict fatigue behavior with a minimum of testing and provides a rational method for selecting metals to resist fatigue. There have been few attempts to determine what cyclic and monotonic properties are necessary to describe and predict the fatigue failure of polymers, however, and this knowledge may be useful when and if these materials are modified to be used for structural purposes. To this end the cyclic deformation and failure behavior of some common plastics is examined.

At least three failure phenomena occur in polycarbonate and polymethylmethacrylate tested in completely reversed strain control at room temperature and at low frequencies: catastrophic fracture, cyclic fracture, and delayed cyclic softening. At high cyclic strains the definition of failure is often arbitrary, and the onset of failure can depend upon the test frequency. In this region it does not appear feasible to relate the fatigue behavior to any monotonic material properties. At low cyclic strains the number of cycles to fracture appears to be independent of the frequency of testing, and the behavior is often described by an equation similar to the Coffin-Manson equation. Moreover, when log strain is plotted against log life, the slope appears to be relatively constant for a variety of polymers. In addition, the plot of stress amplitude versus log life is linear for nylon and polycarbonate in the low strain region and the extrapolation to one reversal is very well approximated by the fracture load divided by the cross sectional area after fracture.
Applications of Finite Element Stress Analysis and Stress-Strain Properties in Determining Notch Fatigue Specimen Deformation and Life
Authors: Mowbray DF , McConnelee JE
Published: March 2009

Finite element elastic-plastic stress analyses were performed on several notched fatigue specimen geometries used in a test program to determine the room temperature and 550 F fatigue strengths of three low strength steels. Specimen geometries included grooved cylinders and wide notched cantilever bend specimens. The analyses were, with one exception, for reversed loading. The objective in these cases was to predict the steady state response of the specimens by using the cyclic stress-strain relationships. The exceptional case represented an initial effort in analyzing a zero-to-tension cycle with a cyclic loading option in the computer program.

The finite element calculated notch root strains were compared with strains measured during the fatigue experiments and with predictions of the commonly used Stowell and Neuber formulae. A good correspondence was found between the experimental strains and those calculated by the finite element method. The Stowell and Neuber formulae were found to overpredict notch root strains at stress levels beyond the initial plastic range. A good correlation of fatigue crack initiation life data for smooth and notched specimens was found using a recently proposed stress-strain function.
Periodic Overloads and Random Fatigue Behavior
Authors: Watson P , Hoddinott DS , Norman JP
Published: March 2009

The occurrence of occasional high amplitude strain cycles in an otherwise stationary random strain time history considerably reduces the fatigue life of mild steel specimens. The acceleration of damage is shown to occur throughout the cyclic damage process. The significance of this effect in terms of fatigue in railway vehicles is emphasized. The results of overload studies are often confusing because of the influence of induced residual stresses. In this work, care was given to ensure that no such effects occurred.
Observation of Defect Clusters of Columbium and Columbium Alloys In Situ Irradiated Under a High-Voltage Electron Microscope
Authors: Igata N , Watari F , Murakami H
Published: March 2009

The nucleation and growth mechanisms of self-interstitial dislocation loops in columbium, columbium-oxygen, columbium-zirconium, and columbium-molybdenum, were studied by the electron irradiation and in situ observation in the temperature range from 10 K to 500 K, using a high-voltage electron microscope. The loop density increased in proportion to the square root of interstitial oxygen concentration. The density first decreased and then increased with the increase in zirconium and molybdenum concentrations. The logarithm of loop density was proportional to the reciprocal irradiation temperature. The growth rate of loops was suppressed by interstitial oxygen atoms; it was enhanced and then suppressed as the concentrations of substitutional zirconium and molybdenum atoms increased. The nucleation and growth mechanisms of self-interstitial loops were discussed from the viewpoint of the trapping effect of self-interstitials and vacancies by alloying atoms. The scavenging effect by zirconium and molybdenum atoms was also discussed.