bluuebunny/crossref_metadata_2025 huggingface dataset:
The Principles of the Radiographic Process
Authors: Norton John T.
Published: September 2009

A discussion of some of the basic principles underlying the radiographic process is desirable if the specific applications of the method are to be thoroughly understood. The present paper deals with the relations existing between the various factors entering into the production of a successful radiograph.

An important part of the radiographic equipment is the detecting device consisting of the photographic film or paper, and the intensifying screens. The factors of contrast, latitude, speed, and definition must be properly related to use this device to its best advantage. The X-ray source also contains several variable factors which the operator must adjust with a view to obtaining the best conditions for the particular problem at hand. The reaction of the X-ray beam with the object results in the X-ray image. Not only must this image be intense enough to operate the detecting device, but also it must show the necessary variations in intensity to reveal the interior structure of the object. Contrast, latitude, and definition are important here as in the detecting device for the two work together in rendering a picture of the object.

The question of sensitivity of the method is of considerable importance, and to apply the method successfully the operator should know the size of the smallest detectable defect. There are many factors which modify the sensitivity and they should be controlled as closely as possible. Finally, the question of proper shielding to protect the film from extraneous X-ray effects forms a vital part of the correct radiographic technique and must be carefully worked out in each specific case.

The principles discussed are fundamental to the process, and by employing them properly, the operator can produce a radiograph which will satisfactorily portray the interior structure of the object he is examining. At the same time, he will be assured that the defects larger than a certain minimum size will definitely appear if they are present so that the method may be applied with considerable confidence.
An Introduction to Gamma-Ray Radiography
Authors: Mochel Norman L.
Published: September 2009

The paper deals with gamma-ray radiography from a rather practical standpoint. A brief history of the development of the practice is included. The use of radium as the accepted source of energy, and the way in which radium behaves are discussed in a brief, and yet sufficient, manner for the purpose. The technique of gamma-ray radiography is covered in a complete manner. Many examples of the use of the method are cited. A Selected Bibliography is included.
Radiography of Welds and Weldments
Authors: Lorentz R. E.
Published: September 2009

The material in this paper consists of developments in the general art of radiography of welds which have come into use since 1936 when an earlier Symposium on Radiography and X-ray Diffraction Methods was held by this Society. The excellent papers given at that time represented the best practices in use. Since that time, a number of developments have been made which are covered in the present paper.

The maximum available voltage has been raised from 400,000 v. to 1,000,000 v. This development has allowed many further improvements in technique. Not only has it raised by many inches the maximum weld thickness which can be radiographed, but it also has allowed the wider use of lead intensifying screens to improve detail in the exograph. It also gives superior techniques for many special applications.

New fine-grained, high-contrast films have come into use which improve greatly the detail of exographs and gammagraphs. Techniques such as double-film viewing, which present many advantages, have come into use, and the trend toward longer film lengths for special cases is discussed.

There have been some changes in code requirements which have come about as a result of wider experience, and these changes are discussed.
An Investigation of the Apparatus Used in Radium Radiography
Authors: Ball L. W. , Draper D. R.
Published: September 2009

In radium radiography, the apparatus used is simple compared with X-ray apparatus, and secondary radiation is relatively unimportant. However, there is still a considerable difference between the good quality of radiographs obtained with a suitable choice of apparatus carefully arranged and the poor quality that can result from unsuitable apparatus and careless arrangement.
An Exposure Meter for X-Ray Radiography
Authors: Friedman Herbert , Christenson Arthur L.
Published: September 2009

An X-ray exposure meter has been developed for use with a 220-kv. X-ray radiographic installation at the Naval Research Laboratory. For given brands of film and intensifying screens, the meter may be calibrated to indicate the exposure times required for any desired film blackening. The dependence of this calibration on kilovoltage, specimen material, and filter technique has been investigated. In routine radiography, it is possible to obtain satisfactory results with a single calibration curve, at all voltages between 125-kv. and 200-kv., for any specimen material, and for filtered as well as unfiltered radiation. The receiving element of the exposure meter is a Geiger-Muller counter designed to permit accurate intensity determinations in a few seconds, with the measured beam of radiation limited to a pencil of X-rays, 1/4 in. in diameter. The use of a small aperture on the counter permits the scanning of portions of castings of nonuniform thickness to determine an optimum kilovoltage and suitable filter technique for radiographing. Since the counter is placed close to the film position, the meter indications are independent of variations in the source-to-film distance.
Equivalent Penetrameters in Radiographic Testing
Authors: Schier Robert J. , Doan Gilbert E.
Published: September 2009

The possibility of using penetrameters next to the film, instead of next to the source, in radiographing pipes is explored and the thickness of these penetrameters to make them equivalent to those used in the A.S.M.E. code is determined experimentally.
Precision Radiography—III
Authors: Schier Robert J. , Doan Gilbert E.
Published: September 2009

This is the third of a series of papers on Precision Radiography, the first appearing in the ASTM Bulletin and the second in the 1940 Proceedings.
The Mode of Attack of Oxygen on Rubber
Authors: Neal A. M. , Vincent J. R.
Published: September 2009

It has long been recognized that rubber, because of its unsaturation, is degraded by atmospheric oxygen, and, in contrast with most unsaturated materials, a very small degree of oxidation is sufficient to destroy its characteristic properties.

The oxidation of rubber, whether vulcanized or unvulcanized, is a complicated process, involving several reactions, each of which is influenced differently by conditions. The existence of more than one reaction is illustrated by reference to the influence of: (1) a given material on raw and vulcanized rubber, (2) chemicals on mill breakdown, (3) different antioxidants in an otherwise similar stock, (4) combinations of metal catalysts, (5) oxygen pressure on the temperature coefficient of the oxidation, (6) temperature on the amount of oxygen required for degradation, and (7) different aging conditions.
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 Effects of Light and Ozone on Rubber
Authors: Blake John T.
Published: September 2009

We are all familiar with the fact that light and ozone are enemies of rubber. Many observations are recorded in the literature which serve to demonstrate the complexity of the action of light. These references cover a period of more than a century. This is not surprising, since exposure to light is inevitable in the service life of most rubber articles. Studies on the effect of ozone cover a much more limited period of time.
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.
Test Methods and Devices for Sintered Iron Rotating Bands
Authors: Dale J. D.
Published: September 2009

This paper is a discussion of the methods and devices used in testing the acceptability of sintered iron rotating bands, which are made by the powder metallurgy technique from commercial grades of iron powder. A state of urgency exists in the supply of copper available for the total military and civilian economy. For the third time in less than 50 years, the end uses of copper must be restricted to those where the combined physical or chemical properties, exclusive in copper, are most completely utilized. Several effective substitute materials are being developed to replace copper and gilding metal rotating bands, and among them is low-density sintered iron.
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.
Some Experiences in Specific Surface Measurement of Metal Powders By Low-Temperature Gas Adsorption
Authors: Haertlein J. B. , Sachse J. F.
Published: September 2009

After reviewing the development of the Brunauer-Emmett-Teller and the Harkins-Jura methods, the authors describe their experiences in the design and operation of the low-temperature gas adsorption apparatus. A report is made of the work done at the Metals Disintegrating Research Laboratories on various methods of particle size analysis on metal powders including Cu, Fe, Pb, Sn, Al, Ni, Zn, Mn, Co, and the oxides of several of them. Comparisons are made of the methods used, and conclusions are drawn as a result of this work.
Marine Exposure Tests of Wood Treated with Various Preservatives
Authors: Richards Albert P.
Published: September 2009

In the search for improved performance of wood preservatives to be used for the protection of marine piling, one of the most difficult phases of the work is that one dealing with the proper evaluation of the materials being studied. It is possible, by means of any one of a number of methods, to screen a series of preservative processes, thereby selecting those that seem to hold some promise of success. However, the translation of such test data into the practical terms of expected service life of full size piling can be extremely misleading. Unfortunately, most of the factors involved in the selection, treatment, and service exposure of marine piling are indefinite in nature and it is extremely difficult to make proper, accurate allowances for all of these factors when existing service data are used for comparative purposes.
The Effect of Composition and Annealing Treatment on the Thermal Stability of Chromium-Molybdenum Alloys of Titanium
Authors: Ogden H R , Holden F C , Jaffee R I
Published: September 2009

Annealing treatments originating in the beta field appeared to produce a stable condition more rapidly than annealing treatments originating in the alpha-beta field. Instability found in a 5 per cent chromium alloy is related to the formation of eutectoid products. The substitution of molybdenum for half of the chromium retards the eutectoid reaction resulting in a more stable condition. Small additions of oxygen to the chromium-molybdenum alloys do not appear to affect stability.
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.
A Micro Notched-Bar Impact Test for Titanium Alloys
Authors: Holden F C , Ogden H R , Jaffee R I
Published: September 2009

A micro-impact test is described. Test specimens can be machined inexpensively from 1/4-in diameter rod stock, which can be of advantage when limited amounts of material are available. Transition temperatures are close to those indicated by the V-notch Charpy test. In addition, the impact energy values (in inch-lb) approximate those for the V-notch Charpy test (in foot-lb). Data are presented for several titanium alloys and for other materials, showing the comparison between this micro-impact test and the standard impact tests.
The Measurement of Elastic Modulus of Titanium Alloys
Authors: Graft W H , Rostoker W
Published: September 2009

The determination of the elastic constants of metals by dynamic methods is well known and has been reported in the literature by many investigators. A large variety of test devices has been employed and all are characterized by relatively high precision. This paper undertakes to review the fundamentals of the dynamic test methods and to describe both the device used and the results obtained in a recent investigation of titanium alloys.
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.
Determination of Gaseous Elements in Titanium
Authors: Fowler R M
Published: September 2009

The general problem of the determination of the gaseous elements oxygen, hydrogen, and nitrogen in titanium is reviewed. Some of the relative advantages of different types of apparatus for these determinations are discussed. A simple, rugged vacuum fusion apparatus for oxygen and hydrogen is described with some detailed observations on the variations in technique required to handle different types of samples. Special iron crucibles for powdered samples are described and examples given of their use in the analysis of sponge titanium.
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.
The Mechanics of Testing Irradiated Materials
Authors: Berggren R. G. , Dismuke S. E. , Feldman M. J. , Wilson J. C.
Published: September 2009

Irradiation testing of materials is a form of environmental testing that is needed to predict or assure the service performance of nuclear reactor components. It is conceivable that, in the future, standards may be written for reactor components, but a great deal of testing must precede the writing of such specifications. Accordingly, the nuclear materials engineer will be concerned with the environmental testing of irradiated materials for many years to come.
Problems of Dosimetry as Applied to Radiation Effects Studies
Authors: Collins C. G. , Calkins V. P.
Published: September 2009

At one time dosimetry could be defined as the determination of the energy absorbed in a medium exposed to nuclear radiations which could induce ionization. In recent years, this definition has needed expansion and clarification in order to encompass the multitudinous requirements for describing quantitatively the radiations of nuclear reactors and other sources which can supply intense radiation over large areas. Dosimetry is now the term applied—loosely—not only to determination of absorbed energy, but also to the measurement and description of radiation fields and their interactions with matter. In addition to its long-term use in biological physics, it is now a subject of importance to nuclear physicists, reactor technologists, and to those concerned with the effects of nuclear radiations on materials.
Westinghouse Testing Reactor
Authors: Agazio A. W. De
Published: September 2009

When the Westinghouse Testing Reactor is placed in operation a versatile irradiation facility will become available for conducting experiments under conditions of high flux, high temperature, and high pressure. The heat output of this reactor when placed into operation will be 20 Mw but the facility is being designed so that a power level of 60 Mw may ultimately be reached.
Survey of the Effects of Neutron Bombardment on Structural Materials
Authors: Castleman L. S.
Published: September 2009

The purpose of this paper is to summarize the results of a survey of the unclassified literature made to determine the effects of neutron bombardment upon the mechanical properties of structural materials. Structural materials—as the term is used herein—are those metals and alloys which contain neither fissionable nor fertile materials and which are used in reactor applications exposing them to neutron bombardment. It is hoped that the information and opinion presented in this paper will prove of some use to metallurgists and mechanical engineers interested in radiation damage to reactor components—especially those who have recently become associated with a nuclear reactor development program and who are newly confronted by the problem.
Radiation Effects on Welds and Notches in Plain Carbon Steels, Stainless Steels, and Non-Ferrous Alloys
Authors: Leeser D. O.
Published: September 2009

Welding of pressure vessels and piping systems for conventional power plants is not particularly unique. However, vessels and components for nuclear power reactors must be recognized as presenting design problems that have not existed in conventional plants. Primary among these problems is an evaluation of welded structures and internal stresses under high, integrated neutron flux levels at various temperatures.
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.
Will ASTM Standards be Influenced by Radiation Effects in Metals?
Authors: Wilson J. C. , Berggren R. G.
Published: September 2009

Materials in nuclear reactors are subjected to conditions and environments that are new in scope and magnitude, and the designer must consider a number of unique factors such as neutron cross-section, radiation heating, and unusual corrosive media. In addition, as numerous recent papers (1–12) have pointed out, neutron irradiation is capable of causing substantial changes in the engineering properties of metals. Because metals are generally less sensitive to radiation effects than other classes of engineering materials, only the metals in the high flux parts of a nuclear reactor will be exposed to enough radiation to cause property changes of significance. Therefore if special ASTM standards are ever written to take into account the effects of irradiation, they need only apply to a very small part of a nuclear power plant.
A Portable Proximity Probe for Detection of Moisture Within a Laminate
Authors: Outwater John O.
Published: September 2009

As the presence of moisture within a laminate may indicate a weakening of the laminate or a leak in the liner during hydrotest, a moisture detector was developed to detect this moisture by a proximity probe that need only be applied to one side of the laminate. The probe does not indicate the quantity of moisture present in absolute terms, which depends on distance from the moisture, but it gives good relative values.
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.
Some Nondestructive Tests for Filament-Wound Structures
Authors: Hendron J. A. , Groble K. K. , Gruetzmacher R. W. , McClurg G. O. , Retzky M. W.
Published: September 2009

Experimental results are given for several nondestructive tests designed to measure the resin to glass ratio, to measure thickness, and to locate voids. The measurement of back-scattered beta particles using a radioactive source show promise for monitoring the resin to glass ratio especially as an in-process control. Two methods of measuring the thickness of nonmetallic materials are discussed and the results of thickness measurements in the range from zero to 3 in. are given for an eddy current “lift-off” measurement method and for a capacitance measurement method. Both of these methods measure thickness from one side only but both require a metallic conductor on the other side. The “corona method” is described and its use for the detection of voids in resin-glass structures is discussed. Experimental results are given showing the size and location of voids which have been found.
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.
Use of Lead Glass Fiber Yarns as Tracers in Radiography of Filament-Wound Products
Authors: Perry H. A.
Published: September 2009

The use of reinforced plastics in pressure vessels, rocket motors, and lightweight structures is impeded by the lack of design codes and by inadequate inspection procedures. A technique for the inclusion of lead glass fiber yarns in products intended for radiographic inspection is described for determining the concentration, orientation, and condition of groups of reinforcements in filament-wound products with or without fabric inserts. The inclusion of a few lead silicate fiber tracer yarns in the primary and secondary reinforcements and the radio-graphic inspection of the molded product may permit a reduction of the thickness and cost of the product and an increase in the allowable strength-weight ratio. This would improve the competitive position of reinforced plastics for use in precision parts and in lightweight structures.
Alkylation of Asphaltenes
Authors: Illman J. C. , Deahl T. J.
Published: September 2009

High-quality roofing asphalts are found to contain high-molecular-weight asphaltenes which exhibit a high tolerance for saturates and have a low carbon-to-hydrogen (C/H) ratio. These asphaltenes are believed to possess a few long, paraffinic side chains rather than many short chains or naphthenic groups. Evidence supporting this hypothesis was provided by the results of experiments in which highly aromatic asphaltenes were alkylated with various saturates by exposure of asphaltene-saturate mixtures to the 3-Mev electron beam of a Van de Graaff accelerator. The base asphaltenes were alkylated with up to 30 per cent of their weight of saturate, producing alkylated asphaltenes of considerably reduced C/H ratio and of increased molecular weight. Using paraffins of carbon numbers 16 to 25, it is estimated that 6 to 10 side chains were present in the average alkylated asphaltene molecule. The blending characteristics were improved in that the saturate tolerance was greatly increased; in addition, coating-grade asphalts blended from the alkylated asphaltenes had improved durability. Decane was less effective as an alkylating agent than were the C16 to C25 paraffins, and waxes in the C40 range presented problems in separation of unreacted wax from the alkylated asphaltene product. Less improvement in durability was found with branched paraffins such as squalane and with naphthenic saturates, thus indicating the desirability of long chain length. Asphalt compositions having these improved charac eristics can be prepared by exposing either the whole asphalt or an asphaltene-rich fraction, together with suitable alkanes, to high-energy ionizing radiation at a dosage of about 109 rads.
Behavior of Asphalts During Prolonged Weathering as Influenced by the Relative Homogeneity of Their Internal Structures
Authors: Oliensis G L
Published: September 2009

Prolonged weathering tests on asphalts disclose marked differences in surface behavior, cracking pattern and crack-healing tendencies, as between self-healing and non-self-healing asphalts; also as between asphalts of those two classes from different specific geographical sources. These performance differences between asphalts from different specific sources are in general borne out by corresponding differences revealed by Weather-Ometer tests and by a number of other tests that have been suggested by various investigators during the last few decades. It is now revealed that they are also being borne out by the relative homogeneity of the internal structure of the asphalts as disclosed by the 30-year-old spot test. However, it is shown that while quality-probing tests of the type here discussed may, each in its particular way, throw valuable light on one or more of the many different functional properties that happen to be vital to the proper performance of an asphalt for its particular purposes, they may each be insensitive to other equally vital properties. Until, therefore, some test or combination of tests of this type has proved itself capable of adequately measuring all those vital functional properties, only longtime actual service tests, or longtime weathering tests accurately simulating the latter, remain the most reliable criteria of true durability.
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.
Effect of Heat on Oxidized Asphalts
Authors: Wronka J. A.
Published: September 2009

Oxidized asphalts stored at elevated temperatures for extended periods of time tend to “fallback” or decrease in softening point and increase in penetration. An analytical method, utilizing a floating glass lid technique, is presented to measure this tendency in the laboratory. The fallback characteristics of oxidized asphalts prepared from two fluxes suitable for processing into prepared roofing grade materials were studied. The rate of fallback was determined to be rapid during the initial storage, followed by a period during which the asphalt was resistant toward further fallback. The asphalts were found to be relatively stable below 475 F, but the fallback tendencies increased substantially above this temperature. Highly oxidized asphalts were more susceptible to fallback than were asphalts from intermediate stages of blowing. Fallback obtained in plant storage approximated that anticipated from laboratory data. The evidence presented indicates that asphalt that has been subjected to fallback can be reprocessed to the original grade.
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.
Transient High Energy Effects in Semiconductors and Insulators
Authors: Honnold V. R. , Berggren C. C. , Emmert R. R. , Peffley W. M.
Published: September 2009

This paper will be concerned with some physical effects that occur in typical semiconductor and insulating materials during and after exposure to a pulse of high energy ionizing radiation. These effects occur typically on a time scale of a few microseconds to milliseconds. These time dependences are found to be governed by the intensity-time history of the radiation pulse and by the relaxation time or times of the physical processes initiated by the pulse.
Transient Radiation Effects in Semiconductor Devices
Authors: Crowe J. W. , Sauer A. J.
Published: September 2009

Transistors in conventional simple circuits were exposed to bursts of x-radiation from a 600 Kv flash x-ray machine. Analyses of the circuit responses are given in terms of electrical equivalent circuits. Electrical and radiation tests are compared.
Radiation Induced Surface Effects on Selected Semiconductor Devices
Authors: Cocca U. , Koepp-Baker N. B.
Published: September 2009

A preliminary investigation into the effects of space indigenous radiation on a number of semiconductor devices is described. A Co60 source was used to irradiate the devices to an ionization level equivalent to that received by a satellite in a typical orbit in a six-month period. Transistor ICBO and diode IR were monitored throughout the irradiation and pre-test and post-test transistor gain measurements were made. The results of the irradiation test are presented in graphical and tabular form. In general, transistor and diode reverse current increased and transistor gain decreased during irradiation. Some recovery was evidenced following storage and temperature annealing cycles.
Transient Radiation Effects on Traveling-Wave Tubes
Authors: Magnuson R. A.
Published: September 2009

This paper discusses the transient radiation effects on traveling-wave tubes that were subjected to three series of tests at the Sandia Pulsed Reactor Facility. Topics included herein are (1) construction and theory of test tubes, (2) instrumentation of tests, (3) variation of tube parameters during tests, and (4) possible failure mechanisms. The tubes were found to be susceptible to pulsed radiation since the gain decreased by 3 to 10 db during the radiation bursts.
Development of a Radiation Tolerant All Solid State Tracking and Command System
Authors: Smith E. A.
Published: September 2009

As a part of the SNAPSHOT program, all equipment which must function during orbital operation of the SNAP 10A nuclear power system must be designed to withstand, in addition to the usual environments of launch and earth orbit, the leakage flux from the on-board nuclear reactor. This flux consists of neutrons and gamma rays which over a one year operating period may produce total doses of 1013 neutrons/cm2 with energies greater than 0.1 Mev, and 2 × 107 Rads (carbon) gammas. To be discussed here are the radiation hardening aspects of the development of a doppler command and tracking system for this program.