bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Four-Bearing Fatigue Life Test Rig
Authors: Hobbs RA 
Published: March 2009

Specially developed machines for fatigue testing of rolling bearing steels frequently operate at stresses higher than the elastic limit, have contact conditions that differ widely from those in practice, or require special expensive test pieces. An alternative view is that standard bearings should be tested under conditions more closely simulating practice but at a stress level high enough to produce an acceptable test duration.
To this end, a rig containing four size 6208 bearings was developed and has been in use for many years. This paper describes the rig, which has recently been approved by the appropriate committee of the British Institute of Petroleum as a proposed test method for lubricating fluids and their effect on fatigue life. Normally, 32 bearings are tested to minimize the effects of scatter inherent in fatigue life testing, and since the rig is relatively in-expensive several may be run concurrently. When the sudden death technique is used, a test may be completed in less than 4 weeks.
The results from the rigs presented show the life improvement associated with vacuum-degassed steels manufactured by a basic electric arc process and the effects of oil film thickness on these lives. Other work exposes the severe life reduction caused by some fire-resistant fluids, and results from modified rigs at elevated temperatures are reported. The technique of sudden death testing is discussed, and results are presented which tend to confirm its validity.
Effect of Test Variables on the Rolling Contact Fatigue of AISI 9310 and VASCO X-2 Steels
Authors: Lamothe RM , Zagaeski TF , Cellitti R , Carter C 
Published: March 2009

An investigation of two gear steels, AISI 9310 and VASCO X-2, carburized to a depth of 1.524 mm, was conducted to evaluate the effect of materials processing parameters on the fatigue lives of these materials in rolling contact fatigue, in single-tooth bending fatigue, and, finally, in a four-square dynamometer gear testing fixture. The study was carried on simultaneously at the International Harvester Co. (IH) and the Army Materials and Mechanics Research Center (AMMRC).
Rolling contact fatigue (RCF) was performed on two types of RCF machines which yielded different mean lives for each material. The RCF testing at IH was done on a machine designed to produce a 30 percent negative slippage at a contact stress magnitude of 3102 MPa (1 MPa = 145 psi). The AMMRC RCF tests, on the other hand, were conducted on a machine designed primarily for evaluating the fatigue life of ball bearings and had no provisions for including slippage. The magnitude of the contact stress obtained in the AMMRC tests was adjusted to 5171 MPa.
The mean fatigue life of VASCO X-2 in comparison to AISI 9310, was approximately five times greater at the B50 mean life on data generated with the IH machine. The higher fatigue life of VASCO X-2 was attributed to surface carbides and retained austenite. However, data generated on the AMMRC apparatus indicated the reverse, that is, the mean life of AISI 9310 steel was greater than that of VASCO X-2. Rationales for the observed differences in mean lives between the different materials and between the results of the two testing apparatuses are presented.
An Evaluation of Double-Torsion Testing—Experimental
Authors: Pletka BJ , Fuller ER , Koepke BG 
Published: March 2009

Recently, the double-torsion (DT) technique has been widely used for fracture mechanics studies of brittle materials. The technique is popular for a number of reasons. First, the compliance analysis of a precracked DT specimen indicates the applied stress intensity factor, KI, is independent of crack length. This allows tests to be run conveniently on opaque samples and in hostile environments. In addition, specimen and loading geometries are simple and easily adapted to most testing machines. Furthermore, specimens generally are precracked easily and slow crack growth data can be obtained using simple load relaxation tests. As in most testing techniques, however, experimental conditions may arise under which the validity of the data may be in question. For instance, the independence of KI on crack length in a DT specimen occurs over only a limited range of crack lengths. The crack propagation characteristics have also been shown to be dependent on the specimen dimensions. Finally, irreproducibility of slow crack growth data occurs under certain testing conditions.
In this paper these and other experimental aspects of the DT test are examined in order to define the conditions under which the data are valid. Among the topics discussed are specimen and loading geometry, precracking techniques, data reproducibility, slow crack growth measurements, and comparisons of DT data with other techniques.
Fracture and Multiple Cracking of Cementitious Composites
Authors: Naaman AE , Shah SP 
Published: March 2009

Cementitious composites consist essentially of a Portland cement paste, mortar or concrete matrix reinforced with steel (primarily) or mineral fibers. Compared to fiber reinforced polymeric and metallic matrices they form in a way a different class of composites. Their primary characteristics are: (1) that the ultimate tensile strain of the matrix is much lower than the yield or ultimate tensile strain of the fibers, and (2) the bond strength at the fiber matrix interface is relatively small (there is little adhesion in the chemical sense).
Attempts have been made to calculate some fracture properties of these composites, using linear elastic fracture mechanics approach, by testing notched beam specimens, notched tension specimens, or cleavage type specimens. The results have been only partly successful because these composites may not show a brittle type of failure depending upon the relative dimensions of the specimen and the length of the critical crack (in the Griffith's sense). Tests on double cantilever type cleavage specimens of Portland cement mortar reinforced with steel fibers showed that a pseudo-plastic zone develops in front of an advancing crack. In this zone the matrix is cracked but the fibers are in a state of pull-out. If the plastic zone is larger than the specimen cross section, then instead of a rapid crack propagation, multiple cracking and ductile failure may occur. The length of the pseudo-plastic zone can be determined from the results of the cleavage tests and depends on: (a) the length, aspect ratio, volume fraction, spatial distribution, and the pull-out behavior of the fibers, and (b) the properties of the matrix.
It is concluded that for cementitious composites for which no fracture testing standards exist, specific experimental techniques to measure fracture properties and analytical approaches to interpret their values, must be developed.
Stress Corrosion Crack Initiation and Growth and Formation of Pellet-Clad Interaction Defects
Authors: Videm K , Lunde L 
Published: March 2009

The critical events leading to stress corrosion failure of fuel rods are poorly understood. The aim of the present work is to acquire data on stress corrosion cracking (SCC) initiation and crack growth and to use these data for improving our understanding of fuel rod failures.
Crack growth has been studied as a function of stress intensity by means of cladding specimens with fatigue precracks of different sizes. The SCC growth rate was found to increase with the ninth power of the stress intensity.
Smooth SCC specimens have been studied under constant load and under constant strain rate conditions. By applying the crack growth functions (determined by experiments with the fatigue precracked specimens), the times spent to propagate a crack and to initiate a crack as a function of stress have been deduced.
The effect of irradiation on the SCC properties has been investigated with specimens irradiated in Halden boiling water reactor (HBWR).
Procedures and Recommendations for the Culture and Use of Daphnia in Bioassay Studies
Authors: Goulden CE , Comotto RM , Hendrickson JA , Hornig LL , Johnson KL 
Published: March 2009

Despite the widespread use of Daphnia magna as a test organism in bioassay studies, little attention has been devoted to conditions necessary for culturing healthy animals in the laboratory or to the quality and quantity of foods required during chronic life-cycle bioassays. Growth, reproduction, and survival in daphnids are very dependent upon the quality and quantity of their food. Different algal species and artificial diets have been recommended as foods for Daphnia but the impact of these foods on the health and reproduction of test organisms has not been carefully analyzed. We used the appearance of individuals (including the presence of lipid reserves), growth, reproduction, and mortality as criteria for evaluating the suitability of three different food types and food concentrations for chronic life-cycle tests and for determining the maximal duration for chronic life-cycle tests that will consistently yield reliable results. The three foods used were (a) a 1:1 mixture of two algal species, Ankistrodesmus falcatus and Chlamydomonas reinhardtii; (b) Selenastrum capricornutum, a green alga often used in bioassay tests; and (c) trout chow (PR-11) and baker's yeast, an artificial food diet.
We recommend that a diet of green algae be used in the culture and feeding of animals in life-cycle tests and that a food concentration of 1.25 mg dry weight of algae per litre of test water be provided for individual cultures daily. If the animals are fed three times a week, then 2.5 mg of algae should be used. We further recommend that lifecycle tests be run for 21 rather than 28 days to minimize the chance of low survival rates in control vessels. Methods are also described for culturing both D. magna and its food for use in life-cycle tests.
Evaluation of a Bacterial Bioluminescence Bioassay as a Method for Predicting Acute Toxicity of Organic Chemicals to Fish
Authors: Curtis C , Lima A , Lozano SJ , Veith GD 
Published: March 2009

The relationship between the toxicity of 68 organic chemicals to fish and luminescent bacteria was evaluated. Chemicals for which 96-h median lethal concentration (LC50) values had been measured for fathead minnows (Pimephales promelas) in flow-through tests at the U.S. Environmental Protection Agency (EPA) Environmental Research Laboratory-Duluth, Minn., were tested using the Microtox toxicity analyzer (Beckman Instruments, Inc.). The Microtox system measures the decrease in luminescence of the bacterium Photobacterium phosphoreum in response to a toxicant. The toxicity end point is the 5-min median effective concentration (EC50), which is the concentration that causes a 50 percent reduction in light output.
The correlation between fish and bacteria toxicity for a composite of industrial chemicals and pesticides had an R2 value of 0.65. However, the relationship of these two end points for a semihomologous series of industrial chemicals appeared to be firm, with R2 being 0.96 for common alcohols. The feasibility of using the bacterial bioassay as a screening test in a cost-effective testing scheme is discussed.
Review of Superalloy Powder Metallurgy Processing for Aircraft Gas Turbine Applications
Authors: Bartos JL 
Published: March 2009

Substantial increases in raw material and labor costs have provided the impetus for many diverse investigations aimed at reducing the manufacturing costs of aircraft gas turbine hardware. One of the most significant programs conducted at General Electric during the past decade involves application of powder metallurgy (P/M) processing technology to the fabrication of nickel-base superalloy rotating components. The evolution of P/M technology and its application to a high-strength superalloy, René 95, in a number of diverse aircraft engine components is described. Initial development concentrated on fabrication of P/M hardware by hot isostatic pressing (HIP) cylindrical powder preforms and forging in a conventional die system to an oversize shape. Subsequent refinement of this HIP plus forge process included HIP for shaped preforms followed by forging in an isothermal die system to a near net shape.
Emergence of a second P/M processing technology, designated as-HIP, in which the powder is simply HIP and heat treated, thus eliminating all secondary metalworking operations, is also reviewed. The technical advantages and constraints, along with the projected economic benefits of this new, highly promising P/M process, are analyzed and examples of its application to engine hardware presented. The future of P/M processing in the aircraft engine business, particularly as related to development of advanced superalloy materials, is also discussed.
A Stability Analysis of Circumferential Cracks for Reactor Piping Systems
Authors: Tada H , Paris PC , Gamble RM 
Published: March 2009

The high ductility and toughness of the stainless steel reactor piping system have made it virtually certain not to experience unstable crack extension. The present study attempts to provide theoretical assurance that the piping system will not suffer unstable crack extension even if severe circumferential cracking should occur. The analysis is based on the tearing instability concept and the tearing modulus criterion. Simplifications are conservatively made to facilitate the complicated analysis. The results are presented parametrically in graphical forms for convenience of general use. An application to a specific example is also discussed.
The results indicate that the ratio, L/R, is of major importance in consideration of crack stability, where L is the length of the pipe between supports and R is the radius of the pipe. It is shown that unstable crack extension would not occur in stainless steel piping systems designed in accordance with the American Society of Mechanical Engineers' (ASME) code even if severe circumferential flaws were present, provided that the values of L/R are less than about 200. Since the values of L/R for boiling water reactor (BWR) stainless steel piping systems are generally much smaller, large margins against unstable fracture are assured for these systems. When L/R exceeds 200, a more detailed analysis would be necessary to demonstrate crack stability.
Beta-Quenching of Zircaloy Cladding Tubes in Intermediate or Final Size—Methods to Improve Corrosion and Mechanical Properties
Authors: Andersson Th , Vesterlund G 
Published: March 2009

Three batches of Zircaloy-2 tubing were beta-quenched prior to the final cold-rolling, cold rolled 80 percent, and annealed at 475 to 575°C. A fourth batch was β-quenched in the final size. For comparison, standard tubing was included in all tests performed. The second-phase particles were studied by means of optical and scanning electron microscopy. Corrosion testing was carried out at 400°C and in high-temperature (475 to 500°C) high-pressure steam. The mechanical tests comprised tension, burst, and creep testing under internal pressure.
Beta-quenching instead of an intermediate or the final anneal results in significant structural changes. The most striking features are the formation of a Widmanstätten structure consisting of plates of α-phase and the reprecipitation of much finer second-phase particles in the plate boundaries. Cold-rolling of β-quenched hollows followed by a final anneal in the α-range will give an equiaxed structure, but the size and distribution of the second phase obtained in β-quenching will not be markedly changed.
The weight gain at 400°C increases slightly as a result of β-quenching in intermediate or final size. In high-pressure steam at 475 to 500°C, on the other hand, such β-quenching has a dramatic beneficial effect on the corrosion resistance. At 500°C, for instance, specimens from tubing β-quenched in intermediate size show weight gain values of 55 to 95 mg/dm2, whereas specimens from standard tubing take values in the range 360 to 4280 mg/dm2. The explanation of this improvement seems to be the existence of small second-phase particles formed in α-plate boundaries as a result of dissolution and reprecipitation during β heat treatment and quenching. Experiences from boiling water reactor (BWR) channel corrosion of β-quenched Zircaloy-4 indicate that the 475 to 500°C high-pressure steam test forecasts very well the in-reactor resistance of Zircaloys to nodular corrosion under BWR conditions.
The short-term strength as measured in tension and burst testing is improved by β-quenching of hollows or finished tubes, whereas such treatment results in a slight drop in ductility, especially for tubing β-quenched in the final size. The 400°C transverse creep strength is increased by the introduction of β-quenching prior to the final cold-rolling. The improvement is caused mainly by small second-phase particles, formed during β-quenching, which give rise to precipitation hardening.
Comparative Findings Using the Slow Strain-Rate, Constant Flow Stress, and U-Bend Stress Corrosion Cracking Techniques
Authors: Daniels WJ 
Published: March 2009

The testing of materials for stress corrosion cracking (SCC) in a use environment involves the risk that cracking may not be found by the test technique. When this happens, immunity to SCC may be incorrectly concluded. To avoid this type of error, the use of multiple testing techniques is recommended.
This report discusses the different findings for Type 304 stainless steel obtained by three SCC testing techniques: the slow strain-rate technique (SSRT), the constant flow stress (CFS) test, and the U-bend test. The comparative studies in 36.5 percent magnesium chloride solution show that the cracking mode has an electrochemical potential dependency. In sodium chloride solutions, in the range of 1 to 20 percent concentration, the studies show that the cracking has a critical strain-rate dependency.
Some Factors Affecting Drainage of Moisture from Wet Insulation in Flat Roofs
Authors: Hedlin CP 
Published: March 2009

Moisture often finds its way into flat roofs where it causes a reduction in the thermal resistance of the insulations and sometimes leads to the destruction of the roofing system. Various methods for removing moisture have been studied, but effective drying is usually difficult to achieve because the natural forces acting to remove moisture are small.
Some moisture may be drained from wet roofs, but because the slope is small or nonexistent and absorptive forces tend to retain moisture it is not usually an effective method. If the retentive forces can be overcome, however, drainage rates can be substantially increased.
In one outdoor study carried out on an experimental roof deck with 2 percent slope glass fiber, perlite-fiber, and wood fiber insulations were found to drain very slowly. Of the moisture contained in the insulation at the outset less than 25 percent drained out in the first 4 months of test.
In a second, laboratory study tests were carried out on a deck 2.4 m long with slopes of 2, 4, and 8 percent using a variety of underlays beneath wet glass fiber insulation. Drainage was slow when a plastic sheet underlay was used, but rates were higher with soil and vermiculite-asphalt underlays. The fourth underlay, polyester fabric, produced drainage rates that varied with deck, slope, and length of flap allowed to hang down at the end of the deck. This flap provides a suction force that increases the rate of moisture flow. As an example, moisture content was reduced from over 70 percent to less than 5 percent by volume in a period of 4 days with a slope of 2 percent and a 75 mm flap.
Residential Moisture Conditions—Facts and Experience
Authors: Johnson RJ 
Published: March 2009

Moisture in new homes built in the late 1940's and early 1950's was a significant problem. Few moisture problems in new homes have been reported to us in the past 20 years or so. Home size, family size, life style, thermal protection, double and triple glazing, and vapor barriers all contribute to the turnabout.
Moisture conditions in homes were looked into in two studies. In one study, 17 homes in four states were probed in mid-March 1977, when it was expected the moisture content of wood framing members would be at their high or near high due to any moisture condensation in walls. All moisture content levels were found to be well within the acceptable and expected range of equilibrium moisture contents (EMC) for wood framing members (6 to 14 percent) and well below the decay level in wood (20 percent or greater). There was no evidence of past or present water damage in any of these homes.
In another study, data were collected for 16 homes in north-central Utah, southern Alabama, northern Ohio, and central Maryland. Measurements were made in each home for approximately 1 week in the summer and 1 week in the winter. All homes had well ventilated attics. Some had attic vapor barriers and others had none. Calculations showed the average absolute humidities in winter in attics for homes with a ceiling vapor barrier were some 19 percent higher than for attics without a ceiling vapor barrier.
Much more extensive measurements probably would show no consequential difference in relative humidity in well ventilated attics with homes having a ceiling vapor barrier or those without. In practice, the millions of house years of experience with well ventilated and insulated attics, having no ceiling vapor barrier and no condensation problems, indicates that extremes of temperature, ventilation and lifestyle rarely occur simultaneously and to an extent necessary to produce attic condensation sufficient to cause moisture damage.
Stress Corrosion Cracking—The Slow Strain-Rate Technique
Authors: Ugiansky GM , Payer JH 
Published: March 2009

Description
Those in the fields of corrosion engineering and metallurgy will find that this publication offers and introduction for those unfamiliar to the slow strain-rate technique (SSRT) for stress corrosion cracking (SCC) in metals and relevant information the application of the technique for specific alloys of chemical environments. For those familiar with the technique, a data base is provided so that the results of the slow strain-rate tests can be compared with results from other SCC tests, such as constant load tests and constant strain tests. It is organized to address from several vantage points the use of the slow strain-rate technique. A series of papers concerns the SCC process and the relationship of the SSRT to relevant phenomena. Interpretation of results is the primary topic of several papers. Other papers discuss the application of the SSRT to specific alloys or environments. In addition, several papers focus on equipment and procedures using tests.
Properties of Austenitic Stainless Steels and Their Weld Metals (Influence of Slight Chemistry Variations)
Authors: Brinkman CR 
Published: March 2009

Description
There are seven papers in this publication. Four deal with the influence of such elements as nitrogen and niobium on primarily elevated temperature behavior of AISI stainless steel Types 304, 304L, 316, and 316H. The other three papers deal with the effects of intentionally added or controlled as well as residual element content on weldability and subsequent mechanical properties of weld metal. Will be of particular interest to the designers, metallurgists, and suppliers of these materials, who must concern themselves heat-to-heat variability and ways of improving properties.
Design of Buildings for Fire Safety
Authors: Smith EE , Harmathy TZ 
Published: March 2009

Description
The Symposium on Design of Buildings for Fire Safety was held during the Annual Meeting of the American Society for Testing and Materials, Boston, Mass., 27 June 1978. ASTM Committee E05 on Fire Standards sponsored the symposium. E. E. Smith, The Ohio State University, and T. Z. Harmathy, National Research Council of Canada, served as symposium chairmen and editors of this publication.