bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen-Absorption Methods: Their Urility and Limitations in the Study of Aging
Authors: Reid Shelton J. 
Published: September 2009

The three methods commonly employed for oxygen-absorption studies—namely, gravimetric, manometric, and volumetric—are briefly reviewed and compared. Illustrative examples of the use of the volumetric method for the study of aging are presented.
The limitations of the method are said to be no more numerous or serious than those of other aging tests. The data are shown to be reproducible and to correlate with changes in physical properties. It is recommended, however, that the data be used in conjunction with other aging tests and not as the only criteria of aging resistance.
Oxygen absorption methods offer great promise for continued use in the study of aging and also for possible use as a test for predicting the probable relative resistance to aging in storage and in service. The need for further study to establish more precisely the degree of utility and the limitations of the method for such purposes is recognized.
Physical Aspects of the Aging of Rubbers
Authors: Throdahl M. C. 
Published: September 2009

Within the past ten years the general trends of theory and experimental evidence suggest that aging or degradation is quite like polymerization in nature. These reactions are chain mechanisms; the physical changes of which are the net sum of several simultaneous processes: (a) cross-linking, cyclization, and continued polymerization which harden and stiffen the rubbers, and (b) scission which produces tackiness in the rubbers and results in loss of tensile strength. The relative degree to which different rubbers are susceptible to these mechanisms is discussed.
Several physical methods are available for isolating and measuring the relative rate of one or both of the cross-linking and scission reactions. Among these the use of viscosity, sol-gel relationships, stress-relaxation, creep and permanent set methods for measuring the oxidation effects in various rubbers are described and interpreted.
The Effect of Temperature on the Air Aging of Rubber Vulcanizates
Authors: Schoch M. G. , Juve A. E. 
Published: September 2009

The purpose of this report is to show the effect of the temperature of exposure in an air aging test on the rate of deterioration of the properties of typical vulcanizates of natural rubber, GR-S, GR-I, nitril rubber and neoprene.
The results show that over the temperature range of 70 C. to 125 C. the rate of deterioration is dependent on temperature, and the temperature coefficient of aging varies between 1.80 and 3.05 per 10 C. depending on the composition of the material and the property being measured.
The nature of the deterioration in all materials tested is the same over this temperature range except for those materials which develop a nonhomogeneous cross-section during aging. Above 125 C. all the materials tested appeared to undergo a different kind of deterioration.
The test tube method of air aging was found to be approximately equal in severity to the oven method.
Porous Stainless Steel Compacts for Transpiration Cooling
Authors: Lenel F. V. , Reen O. W. 
Published: September 2009

The requirements for high strength at elevated temperatures in blades for jet engine turbine wheels are among the most stringent in materials engineering, and the specifications call for alloys high in such strategic materials as cobalt and columbium. Instead of using solid blades which attain temperatures substantially the same as those of the gas stream in which they operate, it has been suggested to use hollow blades which are cooled. The most efficient method of cooling consists in passing a stream of coolant through the walls of a porous blade. This method is called transpiration cooling. Porous blades can be produced by powder metallurgy.
This investigation has the purpose of providing engineering data for materials to be used in transpiration-cooled blades, and in particular, the strength properties for porous materials having the necessary permeability for efficient transpiration cooling by air. These strength properties are determined at room temperature by tensile strength tests and in the temperature range of 800 to 1100 F likely to be encountered in the application by stress-rupture tests. Because exact data on the permeability required are not yet available and because the necessary permeability may vary in different designs, strength data as a function of permeability were determined for a number of austenitic materials which were compacted and sintered from alloy powders.
Development of Titanium-Base Alloys for Elevated Temperature Application
Authors: Crossley F A , Carew W F , Kessler H D 
Published: September 2009

Tension, creep-rupture and stability test results for titanium-base alloys are discussed. For clarity the discussion is divided into three parts based upon alloy complexity. A survey of hot tensile properties of binary alloys indicated aluminum to be the best metallic strengthener on a weight per cent basis. Creep-rupture data are reported for the following binary alloys: 2, 4, 6, and 8 per cent aluminum; 2, 7, and 15 per cent chromium; 3, 15, and 30 per cent molybdenum; and 30 per cent vanadium. Stability data for some of these alloys are reported. Considering tensile ductility, creep performance and stability of room temperature tensile ductility upon exposure to elevated creep conditions, alloys showing promise as binary alloys and as bases for the development of more complex alloys are the following: for application at temperatures up to 300 C (570 F) the 3 Mo, 6 Al and 4 Al alloys; and for application at temperatures approximately 425 to 550 C (800 to 1020 F) the 6 Al alloy.
Creep-rupture testing was done on the following ternary alloys: 6 Al, 0.04 B; 6 Al, 0.5 Be; 6 Al, 6 Cr; 6 Al, 6 Fe; 6 Al, 6 Mn; 5 Al, 5 Mo; 6 Al, 4 Mo; 6 Al, 6 Mo; and 6 Al, 10 Mo; 7 Al, 3 Mo; 8 Al, 4 Mo; 8 Al, 6 Mo; 6 Al, 0.3 Si; 6 Al, 0.5 Si; and 6 Al, 1 Si; 7 Al, 0.5 Si; 8 Al, 1 Si; 5 Al, 2.5 Sn; 5 Al, 5 Sn; 6 Al, 1 Ta; 6 Al, 3 Ta; and 6 Al, 5 Ta; 8 Al, 1 Ta; 8 Al, 3 Ta; and 8 Al, 5 Ta; 6 Al, 2 V; 6 Al, 4 V; 8 Al, 2 V; 8 Al, 4 V; 6 Al, 4 Zr; 8 Al, 3 Zr; 3 Mo, 0.5 Si; and 4 V, 0.75 Si. Most of the creep-rupture testing was done at 425 and 550 C (800 and 1020 F), with a few alloys being tested at 300 or 650 C (570 or 1200 F). Also, the effect of additions of carbon, nitrogen, and oxygen on creep-rupture properties was evaluated. Stability data for some alloys are reported. Ternary alloys showing promise for application, and as bases for the development of more complex alloys are: 5 Al, 5 Mo; 6 Al, 4 Mo; 7 Al, 3 Mo; 6 Al, 2 V; and 6 Al, 4 V. Tin and zirconium show promise as complexing additions which improve creep performance without detriment to tensile ductility.
Quaternary alloys evaluated were of the 6 Al, 3 Mo, X type and 6 Al, 0.5 Si, Y type where X represents additions of 0.04 per cent boron, 0.5 per cent beryllium, 0.3 per cent carbon or 0.5 per cent silicon and Y represents 1 or 2 per cent molybdenum or 4 per cent vanadium.
The most creep resistant alloy developed having good tensile ductility and stability is the 7 Al, 3 Mo alloy. A limited forging study of this alloy indicated that it can be processed to have excellent combinations of strength and ductility.
The Effects of Carbon and Nitrogen Contamination on the Notch Tensile Properties of Titanium
Authors: Klier E P , Feola N J 
Published: September 2009

It has been shown that the notch sensitivity of unalloyed titanium as determined in the notch tension test differs from that measured in the Charpy V-notch impact test. The ductile-brittle transition in the notch tension test occurs at a much lower testing temperature than does that for the impact test.
At a testing temperature of −100 F (−73 C) neither 0.26 per cent carbon nor 0.23 per cent nitrogen leads to embrittlement in unalloyed titanium as determined in the notch tension test.
Properties and Fabrication Characteristics of Wrought Titanium Products
Authors: Stark L B 
Published: September 2009

The primary objectives of this presentation are to review the basic approaches and developmental results of recent activities in the fields of determination of mechanical properties and fabrication characteristics of wrought titanium products. These studies have included a broad study or “overview” of the background in sheet metal testing and fabrication development, the test results obtained in certain sheet fabrication studies, extrusion fabrication development studies, comments on problems it fabrication of forgings, and a general summary of the importance of the interrelationship between materials specifications and the foregoing studies.
The results of these testing programs can be summarized into the following three categories: (1) mechanical properties data and fabrication limits for titanium alloy sheet materials; (2) mechanical properties data and fabrication limits for titanium alloy extrusions; and (3) comments on titanium alloy forgings and their fabrication limits.
Displaced Atoms in Solids—Comparison Between Theory and Experiment
Authors: Dienes G. J. 
Published: September 2009

Bombardment with massive fast particles produces atomic displacements in a solid, and important changes in physical properties arise from the resultant atomic disorder. This paper is concerned with the calculation and measurement of the concentration of displaced atoms produced by nuclear radiations and, in particular, with a critical comparison of theory and experiment.
The theory of displacement production is outlined briefly. The number of atoms displaced in a solid by a given flux of bombarding particles of known energy can be calculated. It is assumed in the theory that the process can be described in terms of hard sphere collisions and that a definite threshold energy may be assigned to the displacement process.
The concentration of displaced atoms can be derived more or less directly from several types of experiments. The following are discussed: (1) neutron transmission studies of reactor-irradiated graphite as well as the numbers derivable from changes in electronic properties and the storage of energy in this material; (2) low temperature resistivity measurements on metals irradiated at low temperatures; (3) measurements of electronic properties of semiconductors after slight irradiation; and (4) optical studies of high melting oxides after slight irradiation. The discrepancy between theory and experiment is of the order of a factor of two for graphite. Such a discrepancy cannot be considered serious for such an intricate process and it is concluded that theory and experiment are in essential agreement in this case. For other types of solids agreement can be claimed only within an order of magnitude. The number of displaced atoms is apparently overestimated theoretically. At the present state of our knowledge it cannot be decided whether the discrepancy in these cases is due to inadequacies in the theory of displacement production or in the theories linking changes in physical properties to the concentration of crystalline defects.
Fast Neutron Effects on Tensile and Hardness Properties of Type 347 Stainless Steel
Authors: Murphy W. F. , Paine S. H. 
Published: September 2009

Non-standard, multiple-notch tension specimens made from both annealed and 70 per cent cold-drawn type 347 stainless steel were irradiated for various times in the Experimental Breeder Reactor at the National Reactor Testing Station in Idaho. The tests were originally started for the purpose of monitoring the effects of high-energy neutrons on reactor structural components made from type 347 steel. During irradiation the specimens were in contact with a liquid alloy of sodium and potassium at temperatures between 228 and 316 C. Rockwell A hardnesses and ultimate tensile strengths were determined and compared with similar data from unirradiated specimens.
Hardness and tensile strength of the annealed specimens continued to increase up to the maximum integrated flux, 4.3 × 1020 nvt. A linear relationship is shown to exist between the measured property and the log of the integrated flux. Evidence for an incipient annealing process is discussed, in which the activation energy for thermal healing is shown to be related to integrated flux. The maximum increase in tensile strength was 36 per cent on a base value of 129,700 psi for the unirradiated specimens. The maximum hardness increase was 14 Rockwell A divisions on a base value of 48.
The results of the tests on irradiated specimens made from cold-drawn stock were somewhat erratic. However, the tensile strength initially increased at a higher rate than for the annealed specimens, but indications are that saturation of property changes has occurred at 1.2 × 1020 nvt.
Comparative Evaluation of Methods for Measurement of Hoop Tensile Strength by Means of an NOL Type Filament-Wound Ring
Authors: Channon Stanley L. , Rubin Louis 
Published: September 2009

A variety of test methods utilizing the Naval Ordnance Laboratory (NOL) type filament-wound ring specimen have been evaluated for their relative merits in determining hoop tensile strengths. The methods studied were the “standard” NOL split disk test, the NOL hydraulic test, and the split disk test using a notched ring specimen. Comparisons of 0.060-in. and 0.125-in. thick ring specimens were made for each of the three test methods, and the effects of three epoxy resin systems were also noted.
The notched ring test, the hydraulic test, and the “standard” split disk test yielded hoop tension test values of decreasing magnitude in the order indicated. Thinner-walled rings for each method gave higher and more consistent results than heavier-walled ring specimens. The type of epoxy resin system used for winding had no apparent effect on the relationship of the results of different test methods.
A Segmented Cylinder Test for Determining Hoop Stress in Composite Structures
Authors: Hanley D. P. , Cole C. K. 
Published: September 2009

The usefulness of a cylinder test for obtaining hoop strength design data for glass fiber composite structures is well recognized. The advantage, theoretically, is primarily in the “statistical” value of fiber strength if uniform loading can be achieved. Both the split-dee and pressurized ring testing methods are limited in this regard; in addition, in the latter schemes it is impossible to test helical windings for structural evaluation.
The history of the Allegany Ballistics Laboratory (ABL) cylinder testing program is briefly reviewed. The development of a mechanical segmented cylinder test method, which provides for uniform radial expansion, is reported. Included are fundamental biaxial performance data on hoop geometries for various glass fiber — resin systems.
Presented, also, is the analysis of the test fixture mechanics with confirmative experimental data. The test method and fabrication of test specimens are outlined.
Developing Standards for Use of Preimpregnated Roving
Authors: Leeds Maurice A. 
Published: September 2009

A description of preimpregnated roving, where used, and significant advantages are presented, as well as the need for applying standards to the preimpregnated roving material, the fabrication process, and the test methods employed.
Material properties for the application of quality control standards are suggested, including resin content, band width, strand tensile strength, tackiness, and strength in a filament-wound specimen. Specific test methods for these properties are discussed including hydrostatic burst of an open-end cylindrical specimen, a rolling ball tackiness test, and an interlaminar shear test. Data obtained on a high-strength, preimpregnated roving material using an elevated temperature-resistant resin system demonstrate the effect the above properties have on the tensile strength and interlaminar shear strength of filament-wound specimens.
Critical areas in the fabrication process are discussed and their importance as applied to the development of standards is indicated. Data are presented to show the effect of winding tension, and the use of heat during winding on the properties of filament-wound structures. The effects of room-temperature, refrigerated, and deep-freeze temperature storage for up to 6 months are discussed.
A table of suggested quality standards for preimpregnated roving is presented.
Corona Detection Techniques as a Nondestructive Method for Locating Voids in Filament-Wound Structures
Authors: Lindsay E. W. , Works C. N. 
Published: September 2009

When high voltages are applied across electrical insulating material coronalike discharges will occur in the small gaps or voids within the insulating material, producing radio noise, or corona pulses, as a result of the high-frequency components in the current generated by the discharge. These voids within the electrical insulating materials can be found by probing the surface of the materials with high voltage and determining the areas that produce corona. Some indication of the size and shape of the void can also be obtained by studying the characteristics of the corona pulse being produced within the void. Thus, corona test methods can be used to locate voids within dielectric materials and to indicate the size and shape of such voids. Moreover, because corona testing is nondestructive, its usefulness as a tool for the filament-winding industry becomes very apparent.
The various corona detection circuits are reviewed and the feasibility of corona test methods as a nondestructive test for locating voids or flaws within filament-wound structures are discussed. The various types of corona detectors used for flaw detection, the present art in relating the size and shape of the void to the corona pulse characteristics, and the areas where investigation and development are necessary in order to perfect the test method are pointed out.
Some Engineering Properties of Built-up Roofing
Authors: Jones P. M. 
Published: September 2009

The prevalence of splitting in built-up roofing during recent years has prompted special studies to be undertaken by the Division of Building Research to determine the causes for these serious failures. The determination of certain engineering properties of the components used in built-up roofing and the complete membrane have received special attention. To determine these properties, a roller-coating technique was developed to prepare membranes and a special grip arrangement was constructed for the tensile studies. These studies were made at 75 F and at −20 F, using two rates of straining.
The results emphasize the secondary role of the bitumen in the strength of the membrane. At both temperatures the felts contribute 80 to 90 per cent of the strength of the membrane, although the actual strengths increased by 70 to 250 per cent as the temperature changed from 75 F to −20 F. The small amount of creep and of notch sensitivity also serve to confirm the secondary role of the bitumen.
Radiation-Induced Electronic Phenomena in Polyethylene
Authors: Zack J. F. , Berg S. 
Published: September 2009

Several electronic phenomena are produced in polyethylene subsequent to exposure to ionizing radiation at cryogenic temperatures. Electrical conductivity is very much increased and luminescence of specific wavelengths occurs at certain threshold temperatures. Spontaneous current generation may occur under certain conditions. We applied these phenomena to investigate the mechanisms by which the electrical conductivity of polyethylene, normally an electrical insulator, is altered by ionizing radiation to the range of semi-conducting materials.
We offer several variations of a simple hypothesis to describe the observed phenomena and discuss relative merits of this hypothesis. An analogy is inferred between the model presented and the band model of conduction for semiconductors.
Assessment of the Flammability of Aircraft Fluids
Authors: Macdonald J. A. 
Published: September 2009

The methods adopted for assessing the fire resistance of aircraft fluids have been critically reviewed. Most attention has been devoted to an examination of methods of assessing the likelihood of spontaneous ignition of fluids under the most severe conditions that may be encountered in flight. The present closed vessel and hot manifold tests are inadequate and may be misleading. Some other tests, for example the wick, spark ignition of spray, and CAA flammability reference scale, are criticized as being too narrow in their scope.
It is suggested that adequate basic information on the flammability of fluids would be obtained by improved versions of two simple tests:
1. Flash point (lower and upper).
2. Minimum spontaneous ignition temperature in a larger isothermal enclosed apparatus.
Where the application involves ignition on the outside of a hot body in cooler surroundings, the effects of environmental factors are so strong that each case should be treated individually, though some guidance can be provided by tests on a 6 in. hot pipe or flat plate.
Industrial and ASTM Fluid Fire-Test Programs
Authors: Early C. L. , Hatton R. E. 
Published: September 2009

As the use of fire-resistant hydraulic fluids has increased over the past 15 to 20 years, so has the number and types of tests used for assessing fire resistance. Organizations which have studied this nebulous fluid property include ASTM, Factory Mutual, SAE, Underwriters' Laboratories, U.S. Bureau of Mines, U.S. Military groups, and several corporations. Tests developed by these groups fall into distinct classes; for example, pressure-spray, molten metal, hot manifold, wick type, etc., but many variations exist among specific procedures of a given test type.
A special group — Section VI of Technical Division N of ASTM Committee D-2 — was established 10 years ago to study fire resistance of fluids, but its progress has been slow. A major problem confronting industry today is the lack of test standardization and interpretation of test results to adequately measure fire resistance of fluids. Cooperative effort is recommended.
LP-Gas Fuel Systems—Design and Performance
Authors: Coon C. W. , Abbott R. G. 
Published: September 2009

Engine test information was combined with physical carburetor measurements to produce correlations which can be used for design purposes. The correlations were phrased in terms of dimensionless groups of variables. A method, based on the correlations, of extending the versatilit of engine test results was proposed.
In addition, preliminary results were presented for tests conducted with a rotary engine operating on LP-Gas.
Precision and Accuracy of Test Methods
Authors: Wernimont G. 
Published: September 2009

All A.S.T.M. committees make use of data which have been obtained by the use of physical or chemical test methods. It is important to know something about the reliability, the precision, and the accuracy of these methods.
If a test method gives results which are erratic and unpredictable, it cannot be considered to be reliable. The reliability of a test method can be studied by planning a series of determinations so that the individual results can be grouped in some logical way. The variability within these small groups can then be used as a yardstick to determine whether all assignable causes of variation have been properly controlled. It is a waste of time to try to evaluate the precision and accuracy of a test method until it has been shown that the method is reliable.
The precision of a test method is a measure of how variable the method is when used under well-controlled conditions. It is convenient to express precision by means of the standard deviation of individual measurements. The average range within small groups of test measurements can be used to estimate the standard deviation.
A test method can be considered accurate when it will give measurements on a sample of test material which do not differ from the known value by more than can be explained by the random variations of the method.
The results of properly designed experiments to establish the reliability of a test method can be profitably studied by the use of simple statistical control charts. Test method precision and accuracy can also be evaluated with the help of this technique.