bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluating Four Types of Soil-Structure Conduit Systems
Authors: Breitfuss TK 
Published: March 2009

New types of concrete pipe conduit construction had been compared analytically with conventional trench-type installations and with construction with soil-cement bedding. The new conduits were of composite construction using in situ concrete bonded to various portions of thin precast cores. Considerable cost savings appeared to be obtainable with composite construction in narrow trenches.
Tests were conducted with the intention of verifying the assumptions. The removal, examination, and reevaluation of the test pipe and backfill are described, as are unexpected delayed responses in the test installation. New analyses are centered on composite and conventional conduits and on two types of concrete backfilled systems, comparing construction techniques and cost estimates. Means are proposed to obtain actual installations which duplicate theoretical conditions to obtain calculated savings.
Fractographic Method of Evaluation of the Cyclic Stress Amplitude in Fatigue Failure Analysis
Authors: Madeyski A , Albertin L 
Published: March 2009

The first part of this paper describes laboratory work results substantiating the correlation of fatigue striation spacings with crack growth rate and with cyclic stress intensity amplitude, ΔK. The results were obtained by transmission electron microscope (TEM) replica fractography of a fracture mechanics type wedge-opening-loading (WOL) steel specimen previously tested in fatigue.
In the second part of this paper, an illustration of a practical application of this fractographic approach is described in detail. The laboratory test results from the first part are applied successfully to the service failure analysis of a crankshaft. Cyclic stresses calculated using a combined fractographic-fracture mechanics method were in good agreement with the values obtained from a theoretical and experimental stress analysis.
Analysis of Fracture Morphology of Hydrogen-Assisted Cracking in Steel and Its Welds
Authors: Kikuta Y , Araki T , Kuroda T 
Published: March 2009

The relationships between fracture morphology of hydrogen-assisted cracking, microstructure, and crystallographic orientation were investigated using the scanning electron microscope.
In the fracture morphology of hydrogen-assisted cracking, quasicleavage fracture, intergranular fracture, and dimple rupture were observed. In the quasicleavage fracture caused by hydrogen, subcracks often were observed along the boundary of martensite lath or ferrite lath, or both, and at the interface between the matrix and carbides.
The unit fracture facet for hydrogen-assisted cracking, therefore, was defined as the region between subcracks. The unit fracture facet for hydrogen-assisted cracking was smaller than that for cleavage fracture of martensite, upper bainite, and bainitic ferrite. Using the etch pit method the crystallographic orientation of the fracture morphology of hydrogen-assisted cracking was found to be the {110} plane.
The fracture morphologies of hydrogen-assisted cracking can be categorized as one of four types, each of which can be explained by the microscopic diffusion behavior of hydrogen.
Fracture of Ti-8Al-1Mo-1V Alloy Fan Blade by Stress Corrosion Cracking and Fatigue
Authors: Lee EU , Mahorter RG , Wacaser JD 
Published: March 2009

Similar fractures occurred in two gas turbine engine fan blades made of Ti-8Al-1Mo-1V alloy. Their analyses and a supplementary test were performed with the aid of scanning electron microscope (SEM) and transmission electron microscope (TEM) fractography to identify the common mechanism(s).
The initial fracture surface of each fan blade exhibited an area of subcritical crack growth. The area in one fan blade contained three blue discolored zones along the crack initiation side, whereas that in the other fan blade was discolored to white-gray. Intergranular separation and transgranular cleavage were evident at the three discolored zones in one fan blade and near the crack initiation site in the other. Cleavage-like facets were predominant in the remaining area of subcritical crack growth. On some of those facets, striations were seen.
A hot salt stress corrosion cracking test of Ti-8Al-lMo-lV alloy plates resulted in discoloration, intergranular separation, and transgranular cleavage, similar to those observed in one fan blade.
The mechanism of initial crack growth is stress corrosion cracking at an elevated temperature in one fan blade and at ambient temperature in the other. The mechanism of subsequent subcritical crack growth is fatigue at ambient temperature in both fan blades.
Examination of Fracture in a Pressure Vessel under Creep Conditions
Authors: Coleman MC 
Published: March 2009

The relevance of creep crack growth data obtained from uniaxial laboratory experiments to the assessment of defects in plants is being investigated in a pressure vessel research program involving full size half-percent chromium-molybdenum-vanadium components containing machined defects. The first vessel in this program contained external circumferential notches in a large pipe and was tested at 565°C and 62.5 MN/m2 steam pressure, during which time crack growth and deformation in the vessel were monitored. Final failure occurred in an explosive manner after 1583 h. This paper concentrates on the fractographic and metallographic aspects of the failure analysis.
Examination of the vessel revealed three fracture modes across the failed ligament. Intergranular creep fracture occurred immediately ahead of the machined notch, followed by 45-deg ductile shear involving extensive deformation and finally low ductility shear fracture causing fast failure. These observations are interpreted primarily in terms of the mechanisms involved, with some consideration given to the mechanics of the fracture. The intergranular creep fracture mode is considered typical of that associated with plant failures and the significance of this in defect assessment is mentioned. The transfer to ductile shear is discussed in terms of the formation of void sheets, and net section yielding is related to uniaxial tensile data. The change in mode to fast shear fracture, attributed to gross overloading, produced an explosive failure.
The main implication of the failure analysis is that defects in this material can be assessed using mechanics describing intergranular creep fracture. Even so, it is demonstrated that in a nominally ductile situation final failure can be rapid and catastrophic.
Comparison of the Threshold Stress Intensities and Fracture Characteristics for Temper Embrittled and Deembrittled 2¼ Cr-1M0 Steel in a Hydrogen Charging Environment
Authors: Hicho GE , Gilmore CM 
Published: March 2009

Fracture toughness tests and fractographic examinations were conducted on temper embrittled and deembrittled 2¼Cr-1Mo steel using double cantilever-beam specimens. The tests were conducted in an aqueous/acetic acid solution containing hydrogen sulfide (H2S). The threshold stress intensity of the temper embrittled specimen tested in the H2S environment was lower than that of the deembrittled specimens tested in a similar environment. For the purpose of comparing fracture appearances, temper embrittled and deembrittled specimens were fractured in air.
The fracture appearances of the temper embrittled and the deembrittled specimens tested in the H2S environment and the temper embrittled specimen fractured in air were predominantly intergranular. The fracture appearance of the deembrittled specimen fractured in air exhibited a transgranular ductile mode of failure. These results indicate that the embrittling effects due to temper embrittlement and to the H2S environment act cooperatively in reducing the threshold stress intensity of 2 ¼ Cr-1Mo steel.
Proposed Fracture Mechanics Criteria to Select Mechanical Fasteners for Long Service Lives
Authors: Grandt AF , Gallagher JP 
Published: March 2009

It is proposed that long service lives may be attained by selecting a fastener system which keeps the stress intensity range during service below the threshold stress intensity range. Using this criterion one may specify the maximum flaw size (from prior damage or initiated by fretting) which will be permanently retained by the residual stress field surrounding the fastener.
An analytical procedure which can be employed to obtain stress intensity factors for practical fastener crack configurations is demonstrated with results for open holes, cold-worked holes, interference fit fasteners, and pinloaded holes. In addition, threshold stress intensity factor data are taken from the literature and presented in a form convenient for use by the design engineer.
Adhesion of Granular Thin Films
Authors: Faure R 
Published: March 2009

With a view to measuring the adhesion of the microscopic metallic grains which constitute granular thin films, we have perfected a dynamic method. Very high accelerations (107 m/s2) are obtained by means of ultrasonic vibration amplifiers.
Investigation of the adhesion of granular silver films deposited on carbon provided very interesting results: the presence of a coalescence phenomenon shows that there are interactions between grains. The adhesion varies according to the size of the grains, and is very low (150 N/m2) compared with that of thick films (5.0 × 106 N/m2).
Finally, our measurement of the adhesion of thick films revealed that the break occurs in the silver very near the silver/carbon interface, and subsequent studies of the growth of silver/carbon show that the grains form on one or several monolayers of silver.
Adhesion Measurements on Thick-Film Conductors
Authors: Hitch TT 
Published: March 2009

The paper briefly reviews the measurement of adhesion of conductor film materials and describes in particular the requirements of thick-film technology. The test methods used to measure thick-film adhesion strength, which have been previously described by other workers, are treated from a fundamental basis and are discussed with reference to the usefulness and practicability of the test both for research and for more routine purposes.
The second part of the paper reviews two thick-film adhesion tests and their use at RCA Laboratories over the past several years. The first test is the thermocompression bonded peel test, which has been used for the adhesion strength measurement of gold-and silver-based conductor films. This test was developed at RCA and has proved useful for films of a wide range of adhesion strengths.
The second test description reviews RCA Laboratories' use of the soldered-wire, peel test. It also treats our progress in eliminating subjectivity from this test by limiting the use of hand operations and by controlling time-temperature cycles required in the assembly of test specimens. For both these tests, more than one failure mode has been observed. The meanings ascribed both to the failure modes and to test data, which are taken when the modes occur, are treated.
Data illustrating the variation in adhesion strength with firing temperature and film thickness are shown for several ink types. These data are correlated with the composition of the inks by grouping the gold and silver inks into three bonding classifications—fritbonded, reactively bonded, and mixed-bonded.
Disk Pressure Testing of Hydrogen Environment Embrittlement
Authors: Fidelle J-P , Bernardi R , Broudeur R , Roux C , Rapin M 
Published: March 2009

The rapture appearances and pressures are compared for clamped disks, biaxially stressed to rupture under upward increasing pressures of helium or of an embrittling fluid such as gaseous hydrogen isotopes. Usually the downward surface is available for observation during the test in progress, but it can be exposed to a second embrittling medium. Factors studied include: (a) for the materials; chemistry (aluminum, cobalt, chromium, copper, iron, nickel, platinum, titanium, uranium, zirconium, etc., base), surface condition, thermomechanical processing, welding, etc., (b) for the testing conditions (- 196 to - 450°C), H2 pressure, purity, pressure increase rate, etc. Low-cycle fatigue and delayed failure tests can also be conducted and discontinuous cracking monitored by various techniques, especially permeation.
The disk pressure test (DPT) can be used for selection and quality control of bulk materials, protective coatings against hydrogen environment embrittlement (HEE), and their processing. Materials selection is made according to screening tests of increasing severity. The DPT shows evidence of other causes of embrittlement and their synergistic effects with HEE, which is quite important. Other advantages of DPT, such as sensitivity, versatility, rapidity, simplicity of operation and maintenance, safety, low cost of specimens and equipment, etc., are outlined and compared to other methods.
The Influence of State of Stress on Low-Cycle Fatigue of Structural Materials. A Literature Survey and Interpretive Report
Authors: Krempl E 
Published: March 2009

A literature survey was made on the influence of state of stress on the deformation and fracture behavior during low-cycle fatigue. Only the phenomenological aspects of fracture and deformation in the low-cycle range (&lt; 105 cycles) are considered. Most of the materials investigated are shown or are assumed to have isotropic fatigue properties so that anisotropy was generally not considered.
For the isotropic case correlation formulas between uniaxial and multiaxial states of stress (strain) are stated in Appendix 1. Individual papers are reviewed to see which formula can best correlate uniaxial and multiaxial data. No single criterion was found which consistently correlates the data. Of all the correlation formulas the von Mises or distortion energy or octahedral shear stress criterion showed the highest degree of acceptance. However, some papers show no good correlation on the basis of this criterion and serious objections are voiced against this criterion on principal grounds. The von Mises criterion gives the same value for two states of stress which differ only by a hydrostatic pressure, it is pressure insensitive. Fatigue fracture is shown to be affected by the superposition of a hydrostatic pressure and therefore a pressure sensitive criterion should be used for correlation.
In future work a clear distinction of the influence of multiaxial states of stress (strain) on crack initiation and crack growth is necessary. Crack initiation and propagation studies are urgently needed. For isotropic fatigue properties pressure sensitive criteria should be incorporated into the constants of a generalized Coffin-Manson law. In the case of anisotropic fatigue properties, new correlation procedures have to be developed.
Application of Pyrolysis-Gas Chromatography to Qualitative and Quantitative Analysis of Polymers
Authors: Krishen A 
Published: March 2009

Characterization of polymer mixtures presents a challenging problem and various techniques have been used for this purpose. One of the simpler methods is pyrolysis in an inert atmosphere followed by direct gas chromatographic analysis of the products. Precise control of the various experimental parameters makes it possible to obtain both qualitative and quantitative data on the polymeric constituents.
The gas chromatographic requirement for an instantaneous injection dictates that the size of the sample be small, the temperature rise should be fast, and the pyrolysis time be short. The Curie-point pyrolysis method comes close to meeting most of these requirements.
Characteristic gaseous products suitable for quantitation were obtained from polyisoprene, styrene-butadiene rubber, polybutadiene, ethylene-propylene-terpolymer rubber, and chlorobutyl rubber. The gas chromatographic conditions were designed to analyze the products which had a very wide range of volatilities. The flame ionization detection offered ample sensitivity for the detection of very small amounts of materials.
The use of absolute peak areas per unit weight of the sample resulted in simpler nonlogarithmic relationships which are suitable for automatic computer calculations.
Certain copolymers of unknown monomer ratio cannot be quantitated in the presence of other polymers containing the same monomeric unit. Monomer ratios in copolymers can be determined in other cases. When mixtures of known types of polymers are used their composition can be determined with a standard deviation of 1.5 percent.
This technique is recommended as a routine analytical method.
New Automatic Tensile Tester
Authors: Budd WJ 
Published: March 2009

The traditional manual techniques required in preparation of samples and machine operation when performing stress-strain testing of elastomers have been a burden to laboratory managers for decades. When repeated in high volume, they became a significant cost factor. As a result, such testing became a prime area of study for automation.
To meet the demands for greater test production, higher reliability of information than was possible with the old methods, and to lower operating costs, Uniroyal developed the BUD II, a fully automated tensile tester. With this machine one operator, using only a minimum of time, prepares specimens and completes up to four times as many tests in a day as with earlier methods, while providing highly reliable and computerized information.
Survey Analyses of Trace Elements in Water by Spark Source Mass Spectrometry
Authors: Crocker IH 
Published: March 2009

The potential role of spark source mass spectrometry in water quality surveillance is perhaps not as widely appreciated as it should be. In this paper an attempt is made to explain what is unique about the technique and how it can augment other more widely used methods of analysis in the study of inorganic constituents of water.
At Chalk River it has been used to examine samples of water from several rivers, lakes, and streams. Most of the elements present in 100 ml of water in concentrations of at least one part in 1011 can be determined in a single analysis.
To date most other comprehensive evaluations of trace element concentrations in water have suffered from a lack either of sensitivity or of broad elemental coverage. It is probable that spark source mass spectrometry can remedy both of these shortcomings. Thus, it can fulfill a path-finding role in studies of toxic, dietary significant, or other especially interesting trace elements.
Guidelines for Quantitative Liquid-Liquid Extraction of Organophosphate Pesticides from Water
Authors: Suffet IH , Wu C , Wong DTL 
Published: March 2009

A systematic approach for the development of quantitative analysis of organophosphate pesticides from water is presented. Information is presented on the different steps of aqueous pesticide residue analysis including liquid-liquid extraction, water and solvent phase separation, solvent drying, and a two-step evaporation of the extract which permits solvent volume reduction to 0.5 ml for recovery at low levels.
The p-value method of approach is used as a guide to optimize the liquid-liquid extraction step. The p-value determined in water is shown to be applicable to other types of water including river water, sea water, and secondary sewage effluent. Recovery studies are presented at nanogram/liter concentrations where the solvent evaporation procedure is shown to be critical.
Experiences in Operating a Continuous Water Quality Monitoring Network
Authors: Hagan JE , Estes RL 
Published: March 2009

Experiences in operating a network of continuous water quality monitors in the southeastern United States have demonstrated the utility of such networks for pollution abatement monitoring. Operation and maintenance procedures and routine calibration and quality control procedures produce highly reliable data. While local cooperators are necessary for economic reasons, the vital role of the trained electronic technician cannot be overemphasized.
Modifications and technical improvements to monitoring equipment are discussed. Problems encountered have been primarily mechanical in nature, particularly pumps.
Computer programs and semiautomated data handling systems have been developed to produce timely reports.
REX, A Computer Controlled Robot for In Situ Water Quality Monitoring
Authors: Birch KN 
Published: March 2009

A new, computer oriented system for automatic in situ monitoring of water quality is proposed which makes full and effective use of modern computer technology. A concept for in situ computer controlled experimenting is developed as a reasonable and effective means of automatically observing the wide range of acquatic parameters needed.
The established capability in the teleprocessing industry is assumed as starting point and an optimal design is sought for a sensing head which would meet current expression of requirements for automated water quality monitors while exploiting the advantages of both hardware and software in a total system context. A working model of such a sensing head was constructed and operationally tested using an EAI 690 hybrid computer to simulate the central computer and telecommunications facility. This sensing head consisted of a peristaltic pump, a servo positioned valve, an array of six electrodes (2 glass pH, 3 silver-silver chloride, and 1 gold micro-electrode) and a thermistor, along with buffer amplifiers and motor controllers to service these devices. A main feature is its design as a remote, computer periferal, like a teletype, which understands up to 64 different commands and which returns coded responses. A second feature is its in situ design making the entire sensor head submersible and operable in depths to 100 m.
A repertoire of programmed experiments was developed for the working model system to show how, for example, it could monitor the water quality parameters; temperature, pH, conductivity, dissolved oxygen, chloride ion, total carbon dioxide, total alkalinity, and a factor called “other ions.”
Sampling Techniques in Urban Runoff Quality Studies
Authors: Marsalek J 
Published: March 2009

Composite as well as sequential sampling techniques are examined with regard to their applicability in urban runoff studies. While inexpensive composite sampling is adequate for the determination of the total pollutant yield from a watershed, the study of variation in pollutant concentration requires sequential sampling.
A rational approach to the development of a sequential sampling program is proposed, weighing the cost of data acquisition against the detail and significance of the information obtained. The design of such a program is based on the adoption of an empirical model for the variation of runoff quality and on the techniques of prediction analysis.
Practical aspects of sampling installations are also considered. Such considerations include the depth of sample withdrawal in a nonhomogeneous media, the capability of a sampler to collect solids, sample cross-contamination, and synchronization between flow records and collected samples.
Stable Carbon Isotope Ratios as Water Quality Indicators
Authors: Tan FC , Pearson GJ 
Published: March 2009

Stable carbon isotope ratios (C13/C12) of man-made organic substances such as petrochemicals and pulp mill effluents are generally different from those of the “natural” organic matter in marine environments. By measuring the C13/C12 ratios of background organic matter in the marine environment and the pollution sources, an estimate of the degree of man-made pollution can be obtained.
Principles of the CO13/C12 technique, analytical methods, and an example of its use are discussed together with the limits of applicability of the approach.