bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture Testing in High Temperature and Pressure Hydrogen Environments
Authors: McCabe DE , Landes JD , Gradich FX
Published: February 2009

Fracture mechanics tests were conducted on a 2¼Cr-1Mo steel in an environment containing 6% hydrogen sulfide and 94% hydrogen at temperatures up to 727 K (850°F) and pressures to 24.1 MPa (3500 psi). A test chamber and accompanying system were designed to test under monotonically rising, sustained, and cyclic loads. This paper contains a description of the design and operation of the system developed to conduct these tests, along with a brief discussion of testing experience and types of results.
Gas Analysis Techniques for High Temperature Corrosion Testing
Authors: Kane RH , Goodell PD
Published: February 2009

This paper describes the application of instrumental methods of gas analysis for the on-line characterization and control of corrosive high temperature environments. By way of example, experimental techniques for the treatment of combustion products and pyrolysis and reformer environments are presented. Methods for broadening the usefulness of gas chromatography and other instrumental measurements, along with practical gas handling techniques, are discussed.
Low Temperature (650 to 700°C) Burner Rig Testing
Authors: Aprigliano LF
Published: February 2009

A low temperature (677°C [1250°F]) 500-h burner rig test using a fuel with 2% by weight of sulfur was made of IN939, a standard cobalt, chromium, aluminum, yttrium (CoCrAlY) coating, and a nickel, chromium, aluminum, yttrium (NiCrAlY) coating. Both the IN939 and the CoCrAlY coating were found to hot-corrode readily. The CoCrAlY coating hot-corroded by a Type 2 mechanism (low-melting point mixed sulfate), while the IN939 showed evidence of both Type 1 (sulfidation) and Type 2 hot corrosion. The NiCrAlY coating was relatively unattacked. A change in the mode of attack was noted in the CoCrAlY coating when the rig temperature dropped to 650°C (1200°F) for 24 h. The corrosion mode may have changed from one in which solid cobaltous oxide is the stable phase at the gas/scale interface to one in which solid cobalt sulfate is the stable phase.
Behavior of Aggregate in the Washington Degradation Test
Authors: Goonewardane K
Published: February 2009

The variations of the Washington degradation test values with particle sizes and times of agitation were studied on some samples of aggregate. The sand equivalent measuring technique was modified to read fines produced. The study has established that the Washington degradation test is a clay leaching test dependent on surface area of charge. Surface attrition also occurs. A mathematical model is proposed which agrees with the samples considered.
Modification of the Thermobalance Method of Clay Determination and Analysis of Clay Mixtures
Authors: Goonewardane K
Published: February 2009

The normal method of determining the clay content in a sample using X-ray/thermobalance was modified to enable a larger number of tests to be carried out simultaneously. The method was applied to study interaction effects in clay mixtures of bentonite (50% montmorillonite), chlorite, illite, and kaolinite.
Dynamic Monitoring of Liquid Systems for Particulate Contamination
Authors: Carver LD
Published: February 2009

Contamination control is important in many kinds of liquid systems. It may be (a) to insure a clean product during packaging, (b) to maintain the performance of a fluid power control system, (c) to monitor the effectiveness of a flushing process for cleaning parts, or (d) to assure cleanliness of photographic and chemical processing liquids. The applications are almost unlimited. The most effective control is achieved by continuous, on-stream monitoring of the flowing liquid. This paper discusses several types of monitors; what each one measures; correlation and calibration techniques; various applications; sampling and operational considerations; and some of the advantages and disadvantages.
Processing of Glass Containers for Parenteral Products
Authors: Anschel J
Published: February 2009

Particulate matter in parenteral solutions has been a problem not readily solved. Efforts are being made to identify and possibly eliminate existing problems by exploring available methods and instruments and by analyzing current data. The selection of glass, the methods of handling glass containers, the methods and machines for washing the containers, and the sterilization process are important areas of concern. Suggestions for standard procedures and specifications are presented.
The Removal of Stearic Acid Monolayers from Glass with Organic Solvents
Authors: Brandreth DA
Published: February 2009

A series of common organic solvents was used to deplete 14C-tagged stearic acid monolayers on zinc borosilicate glass. It was found that solvent water content is of key importance in determining the effectiveness of monolayer removal. Monolayer removal was rapid, with almost all removal taking place within the first 30 s.
Cleaning Borosilicate Glass for Biological Application
Authors: Pantano CG , Hench LL
Published: February 2009

Successful growth of tissue and organ culture in commercial glass flasks requires a cleaning pretreatment. Auger electron spectroscopy is used to characterize the effect of such treatments upon the composition of the thin surface layers which affect cell attachment. This study considers a sodium-borosilicate glass treated, in particular, by rinsing and soaking in water and acidic solutions. The results should also prove useful for understanding the cleaning of similar glass surfaces for other applications.
Empirical Formulations for the Analysis and Prediction of Trends for Steady-State Fatigue Crack Growth Rates
Authors: FitzGerald JH
Published: February 2009

The general characteristics of steady-state fatigue crack growth rates are discussed. An empirical formulation is described where two constants form a basic crack growth rate versus maximum stress intensity Kmax curve, which is a straight line on a log-log graph. The constants that form the base curves for various materials are correlated to Young's modulus. A third parameter that is sensitive to material alloy and environment is described and methods for obtaining this value are presented. Crack growth rate data for several stress ratios can then be projected to the basic modulus-dependent curve, where straight line scatter bands and statistical information pertaining to the overall accuracy of the formulations can be determined.
Arc Tracking in Organic Insulating Materials and the Comparative Tracking Index
Authors: Rayl M , McCarthy DC
Published: February 2009

One possible source of electrical failure in electronic equipment is arc tracking in organic insulating materials. Various tests have been devised to rank materials according to this property. The results of experiments evaluating the International Electrotechnical Commission test for comparative tracking index and the effects of varying certain test conditions on the resulting index are discussed.
A Technique for Measuring Load-Line Displacements of Compact Ductile Fracture Toughness Specimens at Elevated Temperatures
Authors: Mills WJ , James LA , Williams JA
Published: February 2009

A test method developed for measuring load-line displacements in compact ductile fracture toughness (JIc) specimens at elevated temperatures was used to characterize the elastic-plastic (J integral) fracture response of Inconel® X-750 at 75°F (24°C) and ASME SA-387 Grade C steel at 75°F (24°C) and 600°F (316°C). This technique employs a rigid fixture, attached directly to the test specimen, which translates the load-line displacements outside the loading clevises where the displacements are monitored by two linear variable differential transformers (LVDT) inside the elevated temperature environment. To evaluate the proposed displacement measuring technique, displacements and values of J determined by the LVDT method were compared with those determined by the conventional clip gage method. The data obtained from the two displacement measuring techniques were in agreement. In addition, LVDT-determined displacements within the linear-elastic regime were consistent with theoretical displacements.
Plastic Flow and Fracture Under Triaxial Loading
Authors: Ehrenburg DO
Published: February 2009

The purpose of this paper is to develop an algebraic frame of reference for testing under triaxial loading. In the case of moderate confining pressures, certain parameters may be assumed to remain constant, which makes it possible to describe the behavior of a test specimen in terms of relatively simple mathematical equations. In the case of higher confining pressures, the paper is limited to indicating general trends and observing that several parameters approach recognizable limiting values. In the light of these limits, it is possible to predict the behavior of materials under the combined effect of extremely high confining pressure and high temperature.
Mode I Stress Intensity Factors for Round Compact Specimens
Authors: Gross B
Published: February 2009

Mode I stress intensity factors KI were computed for round compact specimens by the boundary collocation method. Results are presented for ratios At/R0 in the range 0.3 to 0.8, where At is the distance from the specimen center to the crack tip for a specimen of diameter 2R0.
Creep-Rupture Properties of Aluminum Alloy A356-T61
Authors: Holt M
Published: February 2009

Permanent-mold test bars of aluminum alloy A356.0-T61 were subjected to elevated-temperature tensile tests and isothermal constant-load stress-rupture tests (for lives up to 10 000 h), under the aegis of the Metal Properties Council. Rupture strength and secondary creep rate data were analyzed by the successive plotting of isotemperature and isotime curves and by the Larson-Miller procedure. A reasonable base for setting allowable stress values for design codes has been developed.
Acoustic Emission of Plain Concrete
Authors: Nielsen J , Griffin DF
Published: February 2009

When a specimen of engineering material is subjected to external loads, stress waves known as acoustic emissions are induced. A unique characteristic of many engineering materials that emit acoustical energy is that upon reloading the specimen does not emit acoustical energy until the magnitude of loading exceeds the prior maximum loading. This investigation was undertaken to determine if this characteristic could be used to disclose the loading history of plain portland cement concrete. The test results show that the unique characteristic is very temporary and therefore cannot be used to determine the prior maximum loading on a concrete specimen. Within a matter of hours concrete subjected to loading within its elastic limit recovers, and acoustical energy may again be released by reloading.
Random Axial Loading of Short Reinforced Laterized Concrete Columns
Authors: Adepegba D
Published: February 2009

The response to random loading of short reinforced laterized concrete columns was investigated by testing, under three cycles of loading and unloading, three columns cast from 1:2:4, 1:1½:3, and 1:1:2 mixes by weight and reinforced with four 12.7-mm (½-in.) diameter mild steel rods. The results obtained from the test showed that randomly loaded columns are capable of withstanding higher compressive stresses (80 to 95% cube strength) before failure than similar columns loaded to failure in one cycle. An attempt was made to discuss the inherent differences between the transformed section theory assumed for an “elastic” concrete component of a composite column and the theory applicable to a “viscoelastic” concrete, which laterized concrete approximates.
Influence of Material Property Variations on the Assessment of Structural Integrity of Nuclear Components
Authors: Chirigos JN , Meyer TA
Published: February 2009

The question, “Where can the generation of new material property data reduce overly conservative design in reactor systems?” presently exists in the nuclear industry. The question is answered by identifying where conservatism exists relative to determining material property variations. Several areas are reviewed to identify conservatism and the sensitivity of structural integrity evaluation results to the property variations. The areas reviewed were fluence dependence of the transition temperature, fracture toughness, the drop in upper shelf toughness, the arrest toughness, the material thermal properties, and the fatigue crack growth rate.
Fatigue Crack Arrest at Low Stress Intensities in a Corrosive Environment
Authors: Nordmark GE , Fricke WG
Published: February 2009

Crack opening displacement measurements and scanning electron microscope observations were used to investigate the cause of fatigue crack arrest that occurred in compact specimens of several aluminum alloys at low stress intensities in simulated sump water. The observations for 7475-T7351 specimens indicate that the crack arrest resulted from a progressive buildup of corrosion product on the crack surface.
Determining Filtration Efficiency by Comparing the Particle-Size Distribution in the Feed Stream to that in the Filtrate
Authors: Johnston PR
Published: February 2009

Exactly how the investigator should make the comparison between the particle-size distribution in the feed stream to that in the filtrate is the subject of controversy between those who determine the cumulative number of particles versus particle diameter and those who determine the number of particles in each of many diameter ranges. The present discussion, based on the number of particles in each diameter range, addresses the question, “What width of a diameter range should be considered?”
Some Parameters Influencing the Release Pressure of Reverse-Buckling Safety Disks
Authors: Beese JG
Published: February 2009

In recent years safety disks based on the principle of the reverse buckling of a spherical, metallic cap have been developed. In this paper the influence on the disk-buckling pressure of (1) the orifice diameter of the flange-holding ring and (2) heat treatment of the dome before assembly is examined. It is found that both orifice diameter and heat treatment influence the value of the reverse-buckling pressure.
Powder-Cushion Gripping to Promote Good Alignment in Tensile Testing
Authors: Lange FF , Diaz ES
Published: February 2009

A tensile testing technique utilizing a powder-cushion between the specimen/grip surfaces has been devised and tested. Bending strains associated with this gripping technique have been determined as a function of load with a buttonhead specimen instrumented with nine strain gages. Experiments with eight different powders showed that lubricating powders such as graphite and boron nitride are more effective in producing good alignment, with graphite considered superior. Alignment obtained with the graphite powdercushion is comparable with that obtained with more complex devices and procedures.
A Hydrostatic Stress-Sensitive Relationship for Fatigue Under Biaxial Stress Conditions
Authors: Mowbray DF
Published: February 2009

Failure criteria for elastic- and plastic-strain controlled fatigue under biaxial loading are proposed. The criterion for elastic strain is defined in terms of the equivalent strain from the distortion energy theory and that for the plastic part as the corresponding equivalent plastic strain, but modified to include a function of the hydrostatic stress component. These criteria are incorporated into the derivation of a relationship for fatigue life in terms of the principal strain amplitude, analogous to a conventional form for uniaxial loading. An analysis of some limited available data from the literature shows the potential predictive capability of the relationship.
Computer-Controlled Stress Intensity Gradient Technique for High Rate Fatigue Crack Growth Testing
Authors: Donald JK , Schmidt DW
Published: February 2009

An automated test system utilizing a computer for data acquisition and machine control was used to obtain crack growth rate data from 2.5 × 10−8 to 2.5 × 10−6 m/cycle (1 × 10−6 to 1 × 10−4 in./cycle) on a compact type specimen. The crack length was monitored continuously by using the elastic compliance technique, enabling the stress intensity K to be increased according to the equation ΔK = ΔK exp [C(a − a0)] (where a0 and a are the initial and instantaneous crack lengths and C is a test variable). Crack growth data were obtained on a Ni-Cr-Mo-V rotor steel by using both different, programmed K gradients and the more conventional constant-load-amplitude method where the stress intensity increases as a function of increasing crack length. Excellent agreement was observed between the two test procedures.
A Compact Specimen for Plane Strain Crack Arrest Toughness Testing
Authors: Crosley PB , Ripling EJ
Published: February 2009

A test method is described for measuring plane strain crack arrest toughness KIa with a compact shaped specimen. The method has a number of advantages over those previously used. Rather than a fatigue crack for initiation, a machine-notched, brittle weld is used, which reduces testing costs. A very stiff loading system consisting of a wedge and bushing assembly allows for much higher ratios of initiation to arrest toughness than those allowed with pin-loaded double-cantilever specimens. The use of large initiation values is expected to allow for larger KIa measurements with modest-sized specimens.
Long-Time Creep-Rupture Tests of Aluminum Alloys
Authors: Leslie WC , Jones JW , Voorhees HR
Published: February 2009

Creep-rupture characteristics of aluminum alloys 1100-0, 1100-H14, 5454-0, 5454-H34, and 6061-T651 were determined in the temperature range 93 to 731°C in tests of up to 64 000 h duration. The steady-state creep rates of 1100-0 and 5454-0 alloys are described precisely by a simple power relation that could not be applied to 1100-H14, 5454-H34, and 6061-T651 alloys because their microstructures changed at elevated temperatures. The Larson-Miller extrapolation technique yielded accurate predictions of the long-term rupture strength of 1100-0 and 5454-0 alloys but was not well suited for predicting the long-term rupture strength of aluminum alloys whose microstructures changed during testing. The rupture strength of notched specimens was always greater than that of similar smooth specimens at the same nominal stress.
An Evaluation of the Effect of Low Temperatures on Mechanical Properties of a Commercial Steel to be Used in the Arctic
Authors: Krishnadev MR , Ghosh R , Cutler LR , Prince JR , Gauvin P
Published: February 2009

The effect of low temperatures on the mechanical behavior of a commercial low-alloy high-strength age-hardenable steel, IN-787, has been evaluated. The results indicate that the steel has remarkably good properties (yield strength, ultimate tensile strength, ductility, notch sensitivity ratio, and high cycle fatigue) in low-temperature environments. The steel retains its good mechanical characteristics even in the aged condition although there is an increase in the yield strength. It has been suggested that it would be useful to include the effect of low temperatures (at least the lowest service temperature) on the mechanical properties of materials in the codes and standards used for selecting steels for use in the Arctic.
Development and Correlation of a Variable-Speed Friction Tester
Authors: Whitfield JK , Mullen WG
Published: February 2009

The need for a laboratory variable-speed friction tester was recognized several years ago when emphasis was placed on laboratory test procedures to predict pavement skid resistance in the field. A tester was needed that could provide speed gradients on small samples or speed gradients that are comparable to those obtained by using the locked wheel skid trailer. The variable-speed friction tester measures pavement or pavement sample friction at various speeds and simulates the capability of the ASTM locked wheel skid trailer with which an excellent field correlation has been obtained. The variable-speed friction tester is reasonably portable and may be used to measure friction values on ramps, curves, city streets, and short bridges where towed-type testers usually cannot be used.
Comparisons of Fracture Toughness Measurements by the Short Rod and ASTM Standard Method of Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-78)
Authors: Barker LM , Baratta FI
Published: February 2009

A multilaboratory blind comparison testing program evaluated the accuracy of the short rod method of measuring the fracture toughness of metallic materials. Valid comparisons between values measured according to ASTM Standard Method of Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-78) and values of the plane-strain critical stress intensity factor as measured by the short rod method of fracture toughness measurement (KIcSR) were obtained for several steels, aluminum alloys, and titanium. The KIcSR values measured by the short rod method were consistently low, averaging 6% below the measurements according to ASTM Standard Method E 399. A 4% adjustment in the short rod calibration constant that had been previously evaluated only to ±7% brings the two sets of measurements into very good agreement. The short rod method thus appears to be a viable alternative for measuring the fracture toughness of metallic materials.
Effect of Clamping Pressure on the Fatigue Strength of Dimpled and Undimpled Loaded Holes
Authors: Lohse AK , Shewchuk J
Published: February 2009

The process of dimpling is applied to improve loaded-hole fatigue strength in the presence of surface fretting such as is found in riveted joints. Dimpling introduces residual compressive surface stress into the region of fretting. It is proposed that this compressive stress delays the formation of crack-site pits and reduces the subsequent crack growth rate. An experimental program was carried out to investigate the comparative behavior of dimpled and undimpled loaded-hole connections in the presence of surface fretting. Specimens of 2024-T3 aluminum alloy were loaded as simulated riveted connections at two values of nominal clamping or fretting (rivet-head bearing) pressure. Experimental results indicate that while clamping pressure influences undimpled fatigue strength, it does not significantly affect dimpled fatigue strength. At the higher clamping pressure, the ratio of undimpled to dimpled fatigue strength is 0.95 at 106 cycles to failure. However, at the lower pressure, and at the same life, the ratio drops to 0.77.
Evaluation of theJIc Testing Procedure by Round Robin Tests on A533B Class 1 Pressure Vessel Steel
Authors: Clarke GA
Published: February 2009

A round robin test program on the determination of JIc values of ductile materials was conducted by twelve different laboratories, representing five countries. The testing program was conducted under the auspices of the Elastic-Plastic Fracture subcommittee, E24.08, of ASTM Committee E24 on Fracture Testing of Materials. Each laboratory tested one blunt notched and five precracked compact specimens. The results showed very little scatter on JIc values when valid tests are performed. Both single specimen tests and multispecimen tests show excellent agreement.

Side grooved specimens were also tested to determine what possible differences exist between side grooved specimens and specimens not side grooved specimens. While the slope of the crack growth resistance (R) lines were different for the two geometries, the JIc values were essentially the same.
Error Analysis of Intrinsic Viscosity Measurements
Authors: Ashar B , Turcotte LR
Published: February 2009

The intrinsic viscosity of polymer solutions is widely used for characterizing the molecular sizes of polymers. The experimental procedure is very involved, and therefore a variety of precautions needs to be observed to eliminate errors. In this paper, a hypothetical case is discussed to demonstrate that the analysis of data can detect the absence or presence of different kinds of errors in the experimental measurements. It is shown that a systematic or constant error in the concentration measurement is the only error that is not reflected anywhere in the analysis and still leads to inaccurate results. Therefore, it is very important to eliminate this error through the automation of instruments.
The Shear Strain to Fracture Characteristics of a Titanium Alloy and an Ultrahigh Molecular Weight Polyethylene Under Complex Loading Conditions
Authors: Grieve RJ , Lawrence R
Published: February 2009

Thin-walled tubular specimens of titanium alloy and an ultrahigh molecular weight polyethylene are twisted at various strain rates up to approximately 100/s with the simultaneous application of an axial tensile load or compressive load. The strain to fracture of the titanium alloy, that is, the point of instability, is calculated and shown to decrease with an increase in the strain rate. It is also shown to decrease with increasing tensile load and increase with increasing compressive load at all the strain rates. The polyethylene also shows a decrease in strain to fracture with an increase in the strain rate but appears to be independent of axial load.
Studies of Impurity Distribution in Electrolytically Refined Copper Cathodes
Authors: Publicover WE , Taubenblat PW
Published: February 2009

Two studies of impurity distribution within electrolytically refined cathodes show broad disparities in the distribution of impurities within one cathode, between one cathode and another, and between cathodes of differing surface (nodulation) characteristics. The findings bring into question the reliability of results based on sampling discrete locations on cathodes.
The Interactions of Stabilized Scrubber Sludge and Fly Ash with the Marine Environment
Authors: Roethel FJ , Duedall IW , O'Connors HB , Parker JH , Woodhead PMJ
Published: February 2009

Scrubber filter cake (sludge) and fly ash have been stabilized into blocks. These blocks have been submerged in an estuarine environment on the north shore of Long Island, N.Y. for nearly two years and have maintained their structural integrity. The blocks were colonized by a diverse aquatic community of marine plants and animals. The uptake of trace metals from the coal waste blocks by the marine organisms was not greater than that found on concrete reference blocks placed nearby. The initial colonization of the coal waste blocks proceeded somewhat differently at first when compared to the concrete blocks; however, by the end of the first year of submersion both materials supported an almost identical community. Little or no physical abrasion or erosion was observed but biological erosion by the boring clam Barnea truncata was observed to occur. The results indicate that ocean disposal of stabilized scrubber filter cake and fly ash in block form appears to be compatible with the marine environment.
Potential for Utilization of Solid Wastes from Sulfur Oxide Control Processes
Authors: Peterson CH
Published: February 2009

Studies at our laboratory in the last several years in fossil fuel conversion processes have included work on coal gasification, oil gasification, and fluidized bed combustion. A common aspect of these high temperature processes is the production of potentially large quantities of spent limestone or dolomite. This brief presentation describes the logic of the experimental program and presents results of initial bench-scale tests. It was shown that fluidized bed combustion residues could be processed into 5-cm cubes with compressive strengths to 13.8 MPa (2000 psi). Such residues appear to have potential for use in some sectors of the construction industry.
Utilization of Fluidized Bed Combustion Wastes
Authors: Collins RJ
Published: February 2009

Atmospheric fluidized bed (AFB) combustion appears to be a promising means for producing energy from high sulfur coal in an environmentally acceptable manner. The process involves burning crushed coal in a bed of limestone or dolomite that has been fluidized by jets of hot air. The resultant by-products are a dry, sand-size spent bed residue and a relatively high carbon fly ash. This discussion focuses on possible uses for this material, the spent bed residue. The paper is a progress report for a research program sponsored by the U.S. Department of Energy to evaluate potential commercial applications for fluidized bed combustion wastes. Included in the paper are laboratory data related to seven separate residue sources; a discussion of promising approaches to beneficiation; and supporting data on several potential applications involving the use of the relatively high calcium content of the material as a lime substitute or in the form of a cementitious structural product. Specific applications include stabilized road base compositions, masonry block, artificial reefs, partial replacement for portland cement, synthetic aggregate, flue gas desulfurization, neutralization of acid mine drainage, and treatment of industrial trade wastes. Also briefly discussed are efforts to evaluate the environmental impact of AFB waste disposal.
Sludge to Fertile Soil—Research Results
Authors: Briggs RW , Freas RC
Published: February 2009

This paper reports on work done by Dravo Lime Co. in the Dravo Corporation Research Facilities with the cooperation of the U.S. Environmental Protection Agency, Project R803999-01-0. The primary purpose of this study has been to combine flue gas desulfurization (FGD) sludges with municipal waste to produce fertile soils. A second objective has been to stabilize and combine coal fine refuse with municipal waste to identify potential stabilization and revegetation techniques. Testing on the FGD municipal waste mixtures has included seedings both under greenhouse conditions and in outdoor test plots. Coal fine refuse-municipal waste sludge mixtures have also been successfully stabilized and have been successfully seeded and tested under greenhouse conditions. Plant varieties that have been growth in these combined waste products include corn, soybeans, oats, ryegrass, and crown vetch.
Computer Data Acquisition Monitoring of the Stress Corrosion Cracking of Depleted Uranium Cantilever Beam Specimens
Authors: Joyce JA , Hasson DF , Crowe CR
Published: February 2009

The objective of this work was to develop and demonstrate a computer data acquisition system to monitor the stress corrosion cracking of laboratory cantilever specimens. Present methods using optical techniques require long time periods to establish the crack growth rate when low crack growth rates are present. These methods also give very limited data and do not show clearly the dependence of the crack growth rate on stress and atmospheric variables. These methods also are incapable of resolving irregularities in the crack growth rate that would exist if oxide-forming and cracking mechanisms were applicable in the material test atmosphere system. The major conclusion of this work is that a computer data acquisition system can be used to evaluate low crack growth rates in relatively short time periods as well as to evaluate the magnitude of variations in crack growth rate about a mean value. Other advantages are that the specimen can be completely enclosed to better control the test atmosphere, other variables like temperature and corrosion potentials can be easily monitored, and a permanent magnetic tape record can be produced for later reanalysis.
The Influence of Some Variables on Extraction Results of Wool Top
Authors: Larsen SA , Kumar R
Published: February 2009

Analyses of test results from interlaboratory tests on extractable matter in wool are reported. A total of ten laboratories were involved in the test that aimed at ascertaining the effect of specimen size, solvent temperature, length of extraction time, and specimen moisture content on the amount of extractable matter. Multiple dependent variable regression analysis of the results using the percentage of extractable matter as a dependent variable showed this to be inversely related (P < 0.01) to specimen size. Extraction time appeared to have some influence, although the relationship was not significant (P > 0.05). It is concluded that the extraction method needs to be revised to specify specimen size.
A Simple Test Method for the Evaluation of Tearing Modulus
Authors: Takahashi H , Khan MA , Suzuki M
Published: February 2009

Material characterization studies using the multi-specimen J resistance curve procedure have been carried out for a variety of alloy steels. These results along with the data from the literature have been used to demonstrate that the J resistance curves can be normalized to a single R curve. It is shown that J-controlled crack growth is reasonably unvarying with the size of the specimen provided the minimum size requirements to insure a J-based dominance of the crack tip region are satisfied. A relatively simple procedure is proposed to permit an assessment of a critical value of the J integral, the slope of the J integral resistance curve, and the tearing modulus from a single specimen.
A Comparative Study of the Effect of Low Temperature on the Fracture Toughness and Cyclic Properties of Two Candidate High-Strength Low-Alloy Steels for Arctic Pipeline Applications
Authors: Krishnadev MR , Cutler LR , Galibois A
Published: February 2009

Because of the need for a better understanding of the effect of Arctic low temperature environments on the mechanical behavior of high-strength low-alloy (HSLA) steels, a comparative study has been undertaken to evaluate the effect of low temperature on the mechanical properties of two candidate steels, columbium-molybdenum “acicular ferrite” HSLA steel and high-columbium HSLA steel. The paper presents the data relating to the effect of low temperature on the mechanical properties, namely, dynamic fracture toughness KId properties, through instrumented impact testing of precracked Charpy V-notch samples and cyclic properties of the two steels. It also discusses the results in terms of their significance to material specification, selection, and performance criteria for safe and economical transportation of petroleum resources from the Canadian Arctic.
Statistical Fatigue Failure Analysis
Authors: Trantina GG
Published: February 2009

A statistical fatigue failure analysis based on the Weibull weakest link concept is described and applied to notched and smooth specimen data to provide an interpretation of the size effect in fatigue results for SAE 4340 steel. The technique of predicting component lifetimes and of calculating effective area and volume is presented.
On the Relationship Between Stretch Zone Formation and theJIntegral for High Strain-Hardening Materials
Authors: Mills WJ
Published: February 2009

The relationship between stretch zone formation, associated with crack tip blunting, and the J integral was evaluated for materials with high strain-hardening capabilities: Incoloy® 800, Inconel® 600, SA-387 Grade C steel, Type 304 stainless steel, and Alloy A-286. A conventional blunting line commonly used in the construction of a J integral crack growth resistance curve accurately describes stretch zone formation in intermediate and high strength alloys. For low-strength, high strain-hardening materials, however, this conventional blunting line overestimates apparent crack extension associated with stretch zone formation, and it results in an overestimation of ductile fracture toughness values. An alternative blunting line that better describes stretch zone formation in this class of materials is proposed.
A Simple Accelerated Strength Test for Portland Cements
Authors: Halsted LE
Published: February 2009

A simple accelerated test for measuring the strengths of portland cements is presented. The test uses 2-in. (50-mm) mortar cubes, cured in a standard cement testing autoclave. With this method it is possible to accurately predict the 28-day cube strengths in two days.
Life Testing of Enclosed Heating Elements
Authors: Starr CD
Published: February 2009

Life tests of 80Ni-20Cr, 70Ni-30Cr, and 35Ni-30Cr-35Fe alloys were conducted in enclosed elements. The life to burnout in accelerated tests at double the rate power, 500 W, gave a life of about 500 h, while tests at rated power, 250 W, were stopped after 20,000 h.

The hot and cold resistance of the magnesium oxide changed during the test but the changes were independent of the type of alloy in the heater. The hot and cold resistance change of the heater wire was larger in the accelerated tests than in tests conducted at rated power. This was the result of a larger loss in chromium from the alloys during the accelerated test. The silicon loss during testing was small but was larger for the rated test than for the accelerated test.

Calculations from electrical data and metallographic examination for both accelerated and rated tests disclose the loss in cross-sectional area of the wire due to oxidation was between 2 and 8%. This very minor change is consistent with previous investigations. The mechanism of change of the heater wire is not similar in the accelerated and rated test. Thus, service life cannot be estimated from accelerated life test data.
A New Method of Detecting Fatigue Crack Propagation in Ferromagnetic Specimens
Authors: Bhattacharya S , Schröder K
Published: February 2009

This paper describes a new method for detecting fatigue crack growth in ferromagnetic specimens. This method is similar to the Barkhausen effect type of measurement, where discontinuous voltage pulses are induced in a pickup coil surrounding a specimen when the specimen is magnetized slowly. As a fatigue crack grows, similar voltage pulses are generated. Simultaneous display of the Barkhausen-type magnetic signals and the acoustic emission signals during fatigue crack propagation show that they are correlated.
Failure Load Criteria for Two Collinear Cracks in a Finite Width Strip
Authors: McLellan DL , Goranson UG
Published: February 2009

The failure load characteristics of finite width strips containing eccentrically located collinear cracks have been determined for a variety of crack combinations. In addition to single cracks, the three cases of two edge cracks of unequal lengths, one edge crack with one internal crack, and two internal cracks have been investigated and analyzed. Combined with the confirmed behaviors for the center crack, the single edge crack, and the symmetrical double edge crack, criteria have been developed to characterize the failure loads for each case. Two internal cracks are described by an elliptical failure load surface with limits of single eccentrically located cracks. The elliptical failure load surface also applies to the case of one edge crack with one internal crack. Two edge cracks demonstrate behaviors which are described by a hyperbolic failure load surface, and are limited by the single edge crack condition. The axis of symmetry for this type of surface is the symmetrical double edge crack behavior.
An Extensometer for Circumferential Strains
Authors: Findley WN , Reed RM
Published: February 2009

An instrument is described for measuring circumferential strains in plastic specimens of circular cross section. It consists of four direct-current differential transformers (DCDTs) suitably mounted on an invar ring. The DCDTs probe the position of the surface of the specimen at opposite ends of two mutually perpendicular diameters. Examples of performance are given for creep of a thin-walled tube of polyurethane.
Tricalcium Silicate Hydration in the Presence of Various Salts
Authors: Kantro DL
Published: February 2009

The hydration of tricalcium silicate (C3S) in the presence of various salts has been investigated by means of conduction calorimetry. The salts used have been classified into four groups on the basis of their reactions with C3S. The temperature dependence of hydration has been examined for C3S by itself and in the presence of four salts. The apparent activation energy varies with extent of hydration, decreasing initially to a nearly constant value, and falling off again as diffusion control sets in.
Effect of Various Accelerating Chemical Admixtures on Setting and Strength Development of Concrete
Authors: Rosskopf PA , Linton FJ , Peppler RB
Published: February 2009

A study of the rate of hardening of concretes which contain inorganic accelerators demonstrates the superior performance of calcium chloride. However, there are significant changes in the compressive strength of concretes at various ages when accelerators are employed. Calorimetric studies of cement mortars show the advantages as an accelerator that calcium chloride maintains over other inorganic salts. Also, calorimetric tests demonstrate what appears to be different mechanisms of acceleration between different kinds of accelerators. Differential thermal analysis (DTA) techniques were applied to a study of the effect of calcium chloride and calcium formate on the early stages of hydration of a cement. DTA patterns show definite differences between the function of the accelerators.
Comparison of Lap Shear Test Specimens
Authors: Guess TR , Allred RE , Gerstle FP
Published: February 2009

The single lap shear test specimen, a method for measuring the shear strengths of structural adhesives, was evaluated in a combined experimental and analytical study. The shear strengths of two structural adhesives were measured with the conventional thin adherend lap shear specimen and with several thick adherend configurations. Shear strengths obtained from thin specimens were too low: failure was controlled by the tensile (peel) strength of the adhesive/adherend interface rather than by the adhesive shear strength. Equally significant was the finding that the relative shear strengths of the two adhesives measured with the thin specimen configuration were opposite the results from the thick adherend specimens. The apparent shear strengths from thick adherend test specimens increased with increasing adherend thickness, an expected result; however, they decreased with increasing adhesive thickness, a trend which did not agree with published analyses. This anomaly is explained by finite element analyses of the shear and normal stress gradients in the adhesive layer.
Effect of Antibuckling Constraint on Determination of Critical Stress Intensity Factor of Aluminum Sheet
Authors: Bucci RJ , Sha GT
Published: February 2009

Tests were made to compare Kc values for Alclad® 7475-T761 determined from 16-in. (406-mm) wide, center-cracked tension panels tested with and without guides designed to prevent buckling from intensifying the crack tip stress field. The tests show that for sheet thicknesses ranging from 0.06 to 0.15 in. (1.52 to 3.81 mm) a multiplication factor of 0.87 is required to convert Kc values obtained employing antibuckling guides to corresponding values obtained without guides. Above 0.15-in. thickness, test panels appeared to be of sufficient stiffness to prevent buckling without the use of guides, and therefore the conversion factor is unity.
Structural Strength of Short, Axially Loaded Columns of Reinforced, Laterized Concrete
Authors: Adepegba D
Published: February 2009

Laterized concrete was defined as concrete in which “stable” laterite fines replace sand. Reinforced and unreinforced laterized concrete short columns of the same dimensions were cast from three mixes by weight and tested in axial compression after approximately 28 days. Strains were taken on steel and laterized concrete at about the mid-height of the columns. The maximum strain recorded on laterized concrete varied between 0.12 and 0.21% and that on steel varied between 0.12 and 0.20%. The ultimate loads of reinforced laterized concrete short columns were observed to be approximately the same as the ultimate loads for unreinforced laterized concrete columns of the same dimension as the reinforced columns.

Shear and cleavage modes of failure were recognized in unreinforced laterized concrete short columns; however, lateral reinforcement prevented the development of short vertical cracks that led to failure in the reinforced laterized concrete short columns.

The load factor for reinforced laterized concrete short columns is about 2. It is concluded that 1:2:4 mix by weight of laterized concrete may not be suitable for structural works because of the large deformation at initial cracking in all the columns cast from the mix. It is recommended that design practice of laterized concrete structures should be based on the conservative elastic method until more information is available about the behavior of the material.
Impact Three-Point Bend Testing for Notched and Precracked Specimens
Authors: Server WL
Published: February 2009

Testing and data analysis procedures developed from a recently completed fracture toughness testing program on ferritic nuclear pressure vessel steels are presented. These procedures describe the measurement of dynamic fracture toughness at stress intensification rates near 105 MPa√m/s using instrumented impact testing of three-point bend specimens. These procedures have been submitted to several ASTM task groups, and it is hoped that these guidelines will be incorporated into current and future interlaboratory activities eventually leading to a standard method for testing.
Tapered Tensile Specimen for Stress Corrosion Threshold Stress Testing
Authors: Jonas O
Published: February 2009

A new type of specimen for determining stress corrosion threshold stress is described. The specimen has a tapered gage length that provides longitudinal stress distribution with a maximum to minimum stress ratio of 1.85. After a constant load stress corrosion test, the surface of the specimen is inspected and the gage length is longitudinally sectioned. In long-time tests the minimum stress at maximum diameter at which cracking is found approaches the threshold value. Applicability of the specimen has been confirmed by tests of several materials in different environments. The specimen can also be used for the testing of stress-induced pitting.
The Polishing Characteristics of Common Rock Types Used as Aggregate in Bituminous Pavement Surfaces
Authors: Dahir SH , Meyer WE
Published: February 2009

Bituminous pavement surfaces constructed with aggregates of different rock types, or of the same rock type but from different sources, often exhibit different friction characteristics under comparable traffic conditions. Rock type, abrasive size, number of wheel passes, and contact pressure between surface and tire have been generally recognized as primary factors that control the polishing process. To investigate the relation of these factors to rock properties, but without bias caused by shape and size of the aggregate or by mix design, flat surfaces of six rock types varying in texture and mineral composition were polished in a laboratory procedure. Silica in eight grades ranging from 5 to 105 μm was employed as the abrasive in polishing the surfaces with a reciprocating rubber pad apparatus, and different abrasive sizes were used in succession. Contact pressure was normally 15 psi (103 kPa), but was varied in some cases. The polish attained was measured as friction with a pendulum tester after each cyle of 6000 passes of the polishing pad. The results indicate that the susceptibility to polishing increases with the softness and homogeneity of the rocks, the fineness of the abrasive, the number of polishing cycles, and increased contact pressure.
The Particle-Size Distribution in AC Fine Test Dust
Authors: Johnston PR
Published: February 2009

AC test dust is widely used in studying the performance of filter media; however, controversy exists over what constitutes the actual particle-size distribution in the fine-grade material. Presented here are (1) an explanation of the difference of opinion regarding this distribution, (2) an example of problems that will arise because of the difference in opinions, and (3) a plea for workers in this field to resolve this difference.