bluuebunny/crossref_metadata_2025 huggingface dataset:
Nickel Ion Bombardment of Types 304 and 316 Stainless Steels: Comparison with Fast-Reactor Swelling Data
Authors: Johnston WG , Rosolowski JH , Turkalo AM , Lauritzen T
Published: March 2009

Annealed Type 304 and annealed and 20 percent cold-worked Type 316 steels have been bombarded with 5 MeV nickel ions at temperatures from 525 to 725 C (977 to 1337 F) and damage levels up to 280 dpa. The peak swelling temperatures are 150 and 115 C (270 and 207 F) higher than the peak swelling temperatures in reactor for Type 304 and 316, respectively. Swellings of over 50 volume percent have been produced in both alloys at the peak swelling temperature. Twenty percent cold-worked Type 316 does not swell appreciably less than the solution-treated material. Comparison of in-reactor and ion-produced swellings, and void sizes and void densities, indicate that the nickel ion bombardment provides an acceptable simulation of fast-reactor damage. The high-dose ion results are used to guide the extrapolation of reactor data to higher fluences, leading to predictions of over 40 percent swelling in annealed Type 304 at 2 × 1023 n/cm2 (fast) and in annealed Type 316 at 3 × 1023 n/cm2.
Void Swelling Behavior of Types 304 and 316 Stainless Steel Irradiated with 4-MeV Ni+ Ions
Authors: McDonald SG , Taylor A
Published: March 2009

A detailed study has been made of the void and dislocation microstructure of Types 304 and 316 stainless steel irradiated with 4-MeV 58N+ at a displacement rate of 5 × 10-3 dpa/s-1. The range of dosages investigated were 20 to 350 dpa at 525 C (977 F) and 20 to 250 dpa at 600 C (1112 F) for Type 304 stainless steel and 20 to 250 dpa at 525 C for Type 316. The maximum swelling data for Type 304 stainless steel may be represented by a power-law dependence on-dosage with exponents of 1.4 and 1.8 at 525 and 600 C, respectively. The swelling at 600 C, which is much greater than that at 525 C, is due to the more rapid growth of voids at the higher temperature. No evidence of a reduction in swelling rate at high dosages was found at either temperature. The swelling of Type 316 stainless steel shows a tendency to be lower than that of Type 304 and, at higher dosages, is a factor of two less. In 20 percent cold-worked Type 316 stainless steel, swelling was suppressed until the dislocation structure was recovered.
Attrition and Stabilization of Void Nuclei: Critical Nucleus Size
Authors: Beeler JR , Beeler MF
Published: March 2009

Computer experiments were performed on the effect of impurity atoms, hydrostatic pressure, uniaxial tension, and radiation attrition on void nucleus stability in alpha-iron. The critical void nucleus size was found to be a 44-vacancy octahedral (bipyramidal) void with (110) facets. Helium atoms, oversize metallic impurity atoms, and carbon-vacancy complexes served as strong centers for heterogeneous nucleation of voids. Carbon-vacancy complexes at void apexes and corners inhibited thermal dissociation. The amount and tenacity of vacancy trapping by carbon atoms increased with hydrostatic pressure up to 110 kilobars.
Void Formation in Some Nickel-Aluminum Alloys During 20-MeV C++ and 46.5 MeV Ni6+ Irradiation
Authors: Hudson JA , Francis S , Mazey DJ , Nelson RS
Published: March 2009

The damage intensity along the ions track during 46.5-MeV Ni6+ irradiations of nickel and nickel-based alloys at void formation temperatures has been calibrated. Swelling versus depth profiles were determined in several nickel foils bombarded to a range of doses with 46.5 MeV Ni6+ at 525 C (977 F). A comparison of these results with previous data on swelling in nickel after 20 MeV C++ irradiation at this temperature was made to calibrate the Ni6+ irradiations.

Void formation in three nickel-aluminum alloys, at 525 C (977 F), to doses up to 60 dpa has been studied. The alloys contained 6, 8.5, and 13.5 atomic percent aluminum respectively and all specimens also contained [10−5] injected helium. They were bombarded with 20 MeV C++ and 46.5 MeV Ni6+. The ‘incubation’ dose for void formation, compared with that for pure nickel, was increased. The void concentration decreased with increasing aluminum content in solution and the presence of Ni3Al (γ) precipitates in the third alloy had little effect on the swelling characteristics. The observations have been interpreted in terms of an interaction between the aluminum in solution and the injected helium which starves many potential void nuclei of gas.
Materials Performance Prediction from Irradiation Test Data
Authors: Yoshikawa HH
Published: March 2009

This report describes a method of determining irradiation effectiveness of different neutron spectra in causing radiation damage to fuel cladding and reactor structural materials. It involves the definition of a semi-empirical damage function or cross section using measured data from specimens irradiated in thermal and fast test reactor spectra. The damage function is applied to design problems involving irradiation effects to reactor structural and fuel cladding materials to predict the fluence that would produce a specific damage level.
High-Temperature Embrittlement of Ferritic and Austenitic Stainless Steels Irradiated up to 1.6 × 1022 n/cm2 (> 0.1 MeV)
Authors: Van Asbroeck P , Snykers M , Vandermeulen W
Published: March 2009

Tension specimens of four basic stainless steels having a body-centered cubic (bcc) or face-centered cubic (fcc) structure without or with nickel addition have been fabricated by casting and by powder metallurgy (without and with TiO2addition). These specimens have been irradiated at 60 C (140 F) up to a 1.6 × 1022 n/cm2 fast fluence (> 0.1 MeV) and ruptured at 700 C (1292 F). A structural and statistical analysis shows that bcc structure, powder metallurgy fabrication methods, TiO2 additions, and transgranular rupture enhance the 700 C resistance to fast neutron embrittlement. The degree of embrittlement is related to the rupture mode before irradiation.
Ductility of Irradiated Type 316 Stainless Steel
Authors: Holmes JJ , Lovell AJ , Fish RL
Published: March 2009

The effect of fast reactor irradiation on the ductility of annealed AISI Type 316 stainless steel is described in terms of strain rate, temperature, and neutron fluence. Creep and tensile data obtained after EBR-II irradiations are presented and analyzed in terms of controlling deformation mechanisms. The basic nature of each deformation process is used to infer ductility loss trends and to define the environmental conditions where specific ductility-fluence relationships apply. The resulting correlation quantitatively describes ductility to fluences approaching 7 × 1022 n/cm2, strain rates from 10−6/h to 104/h, and temperatures from 370 to 760 C (698 to 1400 F).
Effects of Fast-Neutron Irradiation on Tensile Properties and Swelling Behavior of Vanadium Alloys
Authors: Carlander R , Harkness SD , Santhanam AT
Published: March 2009

Fast-neutron-induced void formation in commercial pure vanadium is dramatically reduced by additions of titanium and/or chromium. As little as 1 percent by weight titanium decreases the void number density and void volume fraction by factors of 30 and 100, respectively, compared with pure vanadium after exposure at 525 C (977 F) to a fluence of 1.1 × 1022 n/cm2, En > 0.1 MeV. Additions of 3 percent by weight titanium or greater suppress void formation entirely under the same exposure conditions. Alloys of 10 and 15 percent by weight chromium have also been found beneficial in limiting swelling. Internal-friction measurements show that the reduction in void formation in the vanadium-titanium alloys may be partly related to the removal of interstitial impurities, oxygen, and nitrogen by the titanium to form a coherent precipitate of Ti3O2 or a complex oxynitride. Excess oxygen in the alloy after consumption of the available titanium as a precipitate results in increased void formation and also loss of precipitate coherency.

The tensile properties of V-20Ti alloy are only slightly affected by in-reactor exposures as high as 5.4 × 1022 n/cm2, En > 0.1 MeV. Initial hardening is observed at low fluences and irradiation temperatures that are probably due to point-defect clusters or precipitates nucleating on interstitial impurities. However, the hardening effect saturates after low neutron exposures and is found to be independent of both fluence and temperature. Specimens of V-20Ti irradiated at ∼600 C (1112 F) to the highest fluence of ∼ 6 × 1022 n/cm2, En > 0.1 MeV showed a few voids and a dislocation network. However, under these conditions, swelling is negligible and is not sufficiently severe to cause any noticeable effect on the tensile properties.
Burst Testing of Zircaloy Cladding from Irradiated Pickering-Type Fuel Bundles
Authors: Hardy DG
Published: March 2009

Closed-end burst tests were conducted on sections of fuel cladding cut from five Pickering-type fuel bundles after exposures of 2.5 to 4.8 × 1024 n/m2 (>1 MeV) at 300 C (572 F). Five batches or heat treatments of Zircaloy-2 and -4 were tested at 22 and 300 C (72 and 572 F). Two of the bundles contained an unfueled element in the center ring. The burst test results obtained from fueled and unfueled sheaths are compared with the same cladding batches irradiated to similar fluences without fuel in a fast neutron facility at 125 to 250 C (257 and 482 F) and to unirradiated controls.

The fueled cladding specimens exhibited higher strength and lower total circumferential elongation than unfueled specimens irradiated in the fast neutron facility. Although the fueled cladding was strained as much as 1.2 percent by thermal expansion of the UO2, the uniform elongation in subsequent burst tests was often higher than that obtained on bursting tubing irradiated in the fast neutron facility. Most of these differences were attributed to the different irradiation temperatures that produced a variation in the size distribution of radiation damage and perhaps a variation in the stability of the defect loops under strain.

While there was no visual or metallographic evidence of interaction between the fuel and the cladding, there was a slight difference in properties between the fueled cladding and unfueled sheaths contained in the same fuel bundles. The slightly lower strength and total circumferential elongation of the fueled cladding were taken as evidence of some mechanical interaction, probably the 0.1 to 1.2 percent plastic strain imposed on the sheath by the thermal expansion of the UO2. There were indications of a texture effect in irradiation hardening with the greater values occurring in instances where deformation took place almost entirely by slip.

Hydrogen concentrations in the range 170 to 719 ppm drastically reduced the 22 C (72 F) strength and ductility, but the 300 C (572 F) properties were significantly reduced only in cladding with a low level of cold work.
In-pile Stress Rupture Strength of Three Stabilized Austenitic Stainless Steels
Authors: Closs KD , Schaefer L
Published: March 2009

The in-pile stress rupture strength of three different types of stabilized austenitic stainless steels was studied. The materials tested were a 16Cr-13Ni-Cb steel (20 and 5 percent cold worked), a 16Cr-16Ni-Cb steel (5 percent cold worked), and a 15Cr-15Ni-Ti-B steel (15 percent cold worked). Irradiation time was up to 4800 h, corresponding to a maximum fast neutron fluence (E >0.1 MeV) of 8.2 × 1021 neutrons(n)/cm2. The specimens were irradiated at 615 and 720 C (1139 and 1328 F).

Neutron irradiation caused a marked decrease in time to rupture and rupture strain in all the materials tested. The 15Cr-15Ni-Ti-B steel showed the most severe reduction in time to rupture. This reduction was attributed to high-temperature embrittlement and an increase in creep rate. It was shown that the precipitation behavior of this material was changed by neutron irradiation. The reduction in time to rupture was lower for the 16Cr-13Ni-Cb and 16Cr-16Ni-Cb steels. No enhancement in creep rate could be detected. The rupture strains measured were higher than 1 percent for the two columbium-stabilized steels, whereas they were below 1 percent for the 15Cr-15Ni-Ti-B steel.
Chapter 5—Needed Research
Authors: Walker RD
Published: March 2009

Portland cement concrete, because of its versatility and relatively low cost, continues to be one of the most widely used construction materials throughout the world. As developments occur in the use of concrete as a construction and architectural material, new demands are placed on the quality and quantity of the materials used in concrete. These demands are magnified by increasing shortages, environmental requirements, and zoning regulations.
Chapter 7—Uniformity and Workability
Authors: Smith DT
Published: March 2009

Concrete is a manufactured product. Any successful manufacturing operation requires that the products produced from day to day are uniform and similar in appearance and quality. Concrete manufacturing differs from other types of manufacturing in many important respects which enhance the versatility of concrete for building construction, but increase the problems of quality control and uniformity.
Chapter 8—Making and Curing Concrete Specimens
Authors: Adams RF
Published: March 2009

This chapter covers in general the importance of properly making and curing concrete specimens. In this discussion, the word “making” means paying attention to all the details of mixing the concrete (in the case of laboratory-mixed concrete), specimen molds, placing, consolidation, and finishing the specimens of any kind for either field or laboratory-mixed concrete. “Curing” pertains to temperature, moisture, and time, which are the factors of the curing process of concrete governing the rate of strength gain and many other properties of concrete for which tests are made.
Chapter 9—Setting Time
Authors: Sprouse JH , Peppler RB
Published: March 2009

Scripture's paper on Setting Time [1] published in 1955, summarized the problems involved and the progress made, as of that time, in developing methods for measuring the setting time of concrete. He pointed out that the setting time of cement does not adequately define the setting time of concrete and warned that very misleading conclusions may result from assuming such to be the case. Many criteria for defining setting time of concrete had been suggested, including loss of workability before placing, impairment of bond of freshly placed concrete to concrete in place, time of finishing for floors, ability to strip forms, and early strength gain. Scripture was of the opinion that none of these criteria represents the setting time of concrete, stating that as soon as concrete has any appreciable strength it has certainly set, and conversely, as long as concrete maintains any significant degree of workability, it is not set. He concluded that one or more points between these two extremes represent the setting time of concrete and, like the setting time of cement, will necessarily have to be defined by a particular test method and apparatus. Subsequent investigations of the rate of hardening of concrete have tended to substantiate these conclusions.
Chapter 10—Air Content and Unit Weight
Authors: Bartel FF
Published: March 2009

Tests for air content and unit weight of freshly mixed concrete are made frequently both in the field and in the laboratory. Procedures are outlined in various ASTM standards which are straightforward and well within the capabilities for performance and understanding of the average concrete technician. Further, a minimum of training is required before proficiency in the testing technique is acquired. Nevertheless, an understanding of the limitations of the various methods, together with an appreciation for carefully following details of the procedures, is essential to obtaining and interpreting results.
Chapter 16—Volume Change
Authors: Sawyer JL
Published: March 2009

Concrete is subject to changes in volume during and after the hardening period. This dimensional instability is of considerable importance to the construction industry, and the understanding of the nature of these changes is important for those using concrete as a construction material. These volume changes, if excessive, can result in high stresses and cracking, with resulting poor performance of the concrete. It is an important consideration whether the volume changes occur in hardened concrete or prior to hardening.
Chapter 19—Corrosion of Reinforcing Steel
Authors: Cady PD
Published: March 2009

High quality portland cement concrete, properly placed, consolidated, and cured, provides an environment that will normally prevent corrosion of embedded steel. However, the technical literature abounds with evidence of serious problems related to corrosion of reinforcing steel in concrete, both in terms of frequency of occurrence and magnitude of resultant damage. Reinforced concrete highway structures (principally bridge decks) and structures exposed to seawater or marine atmospheric environments are most prone to this problem. The common denominator is the presence of chlorides which result from the application of deicing salts in the former instance and from the environment in the latter. The costs associated with repair or replacement of concrete bridge decks damaged by reinforcement corrosion is, and shall be for years to come, a major maintenance expense for many highway agencies [1, 2]. While highway bridges are expected to last 30 years or more, many show signs of deterioration in five years or less [3,4].
Chapter 24—Resistance to Chemical Attack
Authors: Tuthill LH
Published: March 2009

Fortunately most concrete in service is not subjected to chemical attack. Concrete is generally less able to resist successfully corrosion of this kind than disintegration by other forces. By chemical attack is meant leaching and acid or sulfate attack.
Chapter 27—Air Content and Unit Weight
Authors: Helms SB
Published: March 2009

The density of concrete is the mass of the solid per unit of volume and, considering weight synonymous to mass, the term unit weight can be used to signify density expressed as kilograms per cubic metre (or pounds per cubic foot).
Chapter 32—Preplaced Aggregate Concrete
Authors: Lamberton BA
Published: March 2009

The term “preplaced aggregate” (PA) concrete describes a method of placing gap graded concrete. As an alternative to blending the fine and coarse aggregate, cement, and water and placing the mixture in a form, coarse aggregate is preplaced in the form and a structural grout is injected into the coarse aggregate mass in such a way as to fill void spaces where it hardens to form dense homogeneous concrete. The process was developed by Wertz to whom a U.S. patent [1] was issued in 1943.
Chapter 35—Shape, Surface Texture, Surface Area, and Coatings
Authors: Ozol MA
Published: March 2009

The equidimensionality and angularity of coarse and fine aggregate particles, the shape of the relief and the degree of relief on their surfaces, the amount of surface area caused by the kind and degree of relief, and the chemical and physical nature of coatings, if present, are all characteristics that significantly affect the properties of both fresh and hardened concrete. Differences in particle shape and surface texture, as between different rock types, will affect the bulk void contents and frictional properties of the aggregates and, in turn, the ingredient proportions, mechanical properties, and economy of the unhardened concrete mixtures made from them.
Chapter 37—Porosity
Authors: Dolch WL
Published: March 2009

Most of the important properties of concrete aggregates are influenced strongly by the volume and dimensions of the internal pore system of the material. These properties include density, strength, absorption, and freezethaw resistance.
Chapter 40—Chemical Reactions Other than Carbonate Reactions
Authors: Diamond S
Published: March 2009

The proper role of aggregates in concrete is usually perceived as mechanical, rather than chemical. Aggregates are selected on the basis of their favorable physical properties, and unless something unusual occurs, they are supposed to remain inert and unreactive chemically.
Chapter 44—Curing Materials
Authors: Carrier RE
Published: March 2009

Environment adjacent to and within a freshly placed mass of portland cement concrete has a profound influence on the ultimate strength and durability which the concrete will exhibit. Temperature and moisture are the two most significant environmental properties. Generally, moist environments having moderately low temperatures provide optimum curing conditions. These conditions allow the cement to hydrate to the fullest extent possible within the physical-chemical limitations which always constrain complete hydration. For a given concrete—one having a fixed water/cement (w/c) ratio, cement factor, and other properties—it is usually desirable to advance hydration to the maximum extent possible through maintenance of a favorable curing environment.
Chapter 46—Mineral Admixtures
Authors: Tuthill LH
Published: March 2009

Admixtures generally are used to provide an economical means of improving one or more properties of fresh or hardened concrete. Among the effects sought are: reduction in bleeding, increased workability, acceleration or retardation of hydration or setting, increased strength, reduction in heat of hydration, added resistance to freezing and thawing, increased impermeability, improved resistance to aggressive waters and soils, and reduction of expansion caused by reactive aggregate and alkalies in cement. It should be noted that many of these improvements may be obtained without the use of admixtures if proper steps are taken in the design of concrete for the desired uses. However, admixtures designed for specific uses may effect the desired improvements in properties at a lower cost. Economy is, therefore, one of the matters of prime consideration.
Chapter 47—Chemical Admixtures
Authors: Mather B
Published: March 2009

The original version of ASTM STP169 [1] published in 1956 did not have a chapter on “Chemical Admixtures” since at that time there was no ASTM standard covering chemical admixtures. The ASTM Specification for Chemical Admixtures for Concrete (C 494) was originally issued in 1962 and, hence, in ASTM STP 169-A [2], issued in 1966, there was a chapter. It was prepared by Dr. Bruce Foster [3]. The present chapter is an updating of Dr. Foster's paper.
Chapter 49—Organic Materials for Bonding, Patching, and Sealing of Concrete
Authors: Schutz RJ
Published: March 2009

Concrete is one of the most durable materials of construction. However, because concrete is inherently porous and alkaline, it can be attacked both physically and chemically by certain injurious solutions including acids, salts, and water. Penetration of concrete by water or injurious solutions is especially severe where the concrete is exposed to alternate cycles of wetting and drying or freezing and thawing, or both.
Environmental Safety Assessment of New Materials
Authors: Kimerle RA , Gledhill WE , Levinskas GJ
Published: March 2009

A need exists to devise systematic procedures to evaluate the hazard to aquatic organisms of new materials prior to their commercialization. Assessment of hazard implies decision making and risk taking. Now, more than ever before, companies must incorporate environmental safety considerations into that decision-making process of new product development.

A tentative procedure is presented which utilizes environmental fate and aquatic organism toxicity data in the sequential phases of screening, predictive, confirmative, and monitoring studies to arrive at a decision either to continue the toxicity testing, terminate the project because of unacceptable risk, or cease testing because of an acceptable risk. Application of the procedure to a number of potential new products in the past few years has verified the utility of the approach.

The procedure was also tested on three hypothetical materials that varied widely in their use, chemical, physical, and toxicological properties. This analysis demonstrated the flexibility of the system for aquatic hazard evaluation and decision making.
Summary of Proposal Procedures for the Evaluation of Aquatic Hazard
Authors: Maki AW , Duthie JR
Published: March 2009

The development of generalized programs for the evaluation of hazard to aquatic organisms associated with the use of both existing and new chemicals is a major concern of several organizations currently attempting to establish regulations for chemicals potentially reaching the aquatic environment. Two of these groups actively working toward acceptable hazard evaluation schemes are the Aquatic Organisms Section of the American Society for Testing and Materials (ASTM) Subcommittee E35.21 on Safety to Man and Environment, and the American Institute of Biological Sciences (AIBS) Aquatic Hazards of Pesticides Task Group.

An important ASTM goal is the development of a standard practice for a laboratory testing scheme to evaluate hazard to nontarget aquatic organisms. The current draft of the procedure identifies several key decision points and, depending on resultant data, can consist of as many as three distinct phases: (a) an outline of priority and scope, (b) acute hazard, and (c) overall hazard. The testing scheme has provisions for examination of the usage and disposal patterns of a substance and its biological, physical, and toxicological properties in a stepwise manner using sequential evaluation and feedback to select supplementary tests or implement decision alternatives. The program is intended for general application to any of the wide variety of chemical substances potentially reaching natural surface waters.

The AIBS Task Group for the Aquatic Hazards of Pesticides was formulated at the request of the U.S. Environmental Protection Agency (EPA), Office of Pesticide Programs, to assist in the development of an organized and uniform aquatic safety testing program for use in pesticide registration and registration-oriented research. Specifically, the group has been concerned with the development of criteria and rationale for use with the currently required, basic aquatic test data to determine the need for additional testing. A strong emphasis is placed on the development of simple criteria for decision making relative to evaluation of the aquatic hazards of pesticides with the recognition that the criteria ultimately should aid in the exercise of flexible good judgment concerning the need for additional testing.

Current drafts of the respective programs developed by these two groups are summarized here as a basis for an evaluation and discussion of decision criteria employed in aquatic environmental hazard assessments.
Characterization of Composites for the Purpose of Reliability Evaluation
Authors: Halpin JC , Jerina KL , Johnson TA
Published: March 2009

A philosophy of design based on the prevention of failure is defensible and workable. One such philosophy is reliability based design and is the target of our work. The reliability of a structure depends upon a description of the material system (for example, strength) and the attendant uncertainties in this description (for example, scatter in strengths), along with a description of the structural complexity, expected structural loads, and expected operating environment and their attendant uncertainties.

We will discuss, develop, and experimentally verify, wherever possible, models for composite material behavior. These models include a description of static failure resistance by lamination theory combined with energy based fracture mechanics criterion for failure, and a description of wearout via kinetic fracture mechanics. The relationships between the material's capability, as defined by these models, and the anticipated use and misuse reflected by the expected loads and environments will be defined and implemented. Our goal is to define critical technical areas for the development of structural composites; progress can be made only by examining these critical areas and confirming, extending, or redeveloping the tools described here.
Method for Estimating Fracture Strength of Specially Orthotropic Composite Laminates
Authors: Konish HJ , Cruse TA , Swedlow JL
Published: March 2009

A method is presented for estimating the stress intensity factor characteristic of crack extension in a specially orthotropic advanced fiber composite laminate, based on the elastic properties and ultimate principal strengths of a lamina, the laminate construction, and the experimentally determined value of the characteristic stress intensity factor of an arbitrary angle-plied, midplane symmetric laminate. A comparison of the results obtained from this method with limited experimental data for graphite/epoxy laminates indicates that the method is quite accurate for this particular material system.

The predictive method is also used, in conjunction with experimental data, to estimate the size of a damage zone surrounding the crack tip. The implications of the size of this damage zone are discussed briefly.
Deformation and Failure of Boron-Epoxy Plate with Circular Hole
Authors: Daniel IM , Rowlands RE , Whiteside JB
Published: March 2009

The behavior under uniaxial tension of a boron-epoxy composite plate with a circular hole was studied by means of experimental stress analysis and finite-element methods. The specimens were 10 by 26 in. boron-epoxy panels of [0/±45/0/90¯]s layup. They were instrumented with strain gages, photoelastic coatings, and moiré grids. The latter were analyzed using moiré fringe multiplication techniques. Strain distributions as a function of applied nominal stress were obtained along the axes of symmetry and around the boundary of the hole. Young's modulus and Poisson's ratio were computed from the far-field strains. Tensile and compressive strain concentrations were computed for the linear range of strain response. Experimental results were compared with those obtained by homogeneous anisotropic elasticity and by finite-element analysis. The mode of failure was a combination of interlaminar shearing and tensile cracking starting at the hole boundary off the horizontal axis, at a point where the elastic shear stress and strain reach their maximum and where the tangential normal and shear strains increase rapidly and nonlinearly with load. The average applied stress at failure was 42 200 psi compared with a coupon strength of 94 000 psi. The average ultimate tensile strain at the hole boundary on the horizontal axis was 8 X 10-3 in./in. compared with a coupon ultimate strain of 6.8 X 10-3 in./in. At higher loads the peak of the tensile strain shifted, resulting in a higher ultimate strain away from the boundary.
Free-Edge Effects in the Characterization of Composite Materials
Authors: Whitney JM
Published: March 2009

In the use of flat specimens for the characterization of composite materials, stress free edges often are encountered. In the case of laminated tension specimens, such free edges induce interlaminar stresses which can disturb the desired state of stress. Large stress concentrations can be induced by free edges, such as in the rail shear test. Other examples include the sandwich beam test. A general review of free-edge problems as related to composite characterization is presented, including a discussion of narrow versus wide specimens. Particular attention is given to the sandwich beam test where a preliminary analysis of the free-edge problem reveals a state of stress which differs from a tensile coupon.
Effects of Specimen Geometry on the Strength of Composite Materials
Authors: Kaminski BE
Published: March 2009

This paper demonstrates the statistical relationships which exist between test specimens of different designs and how these relationships can be utilized in strength predictions. The specimens selected were the straight-sided tension coupon, uniaxial sandwich beam, and the acceptance-type flexure coupons. Experimental data were obtained for the [0]c, [90]c, [02/±45]c, [±45/902]c, and [0/±45/90]c laminates fabricated from Narmco 5505 boron-epoxy at various temperatures ranging from -65 to 420 F.
Influence of the Free Edge upon the Strength of Angle-Ply Laminates
Authors: Pipes RB , Kaminski BE , Pagano NJ
Published: March 2009

Strength characterization of the fiber-reinforced laminated composite materials is quite often accomplished through the utilization of the finite-width tension coupon specimen. Recent analytical studies have shown that the state of stress in the vicinity of the free edge of such a laminate is fully three dimensional in nature and may not be predicted by laminated plate theory. Furthermore, experimental results have revealed that while the strength of angle-ply tensile coupons of certain fiber orientations are predicted adequately by laminate strength theories, coupons of other fiber orientations are not. As an explanation of this result, it is argued that large, nonlinear shear strains occur at the interfaces for fiber orientations leading to near maximum shear coupling compliances. Further, these strains allow the initiation of matrix cracks at the free edge, which are ultimately responsible for the premature rupture of the coupon. Experimental evidence which supports these arguments is presented.
Pure Bending of Helical Wound Composite Cylinders
Authors: Pagano NJ
Published: March 2009

In order to simulate the influence of specimen misalignment, we determine the elastic response of a helical wound composite tube under pure bending using an existing general solution for a wide class of boundary value problems. Theoretical results for several composite materials of engineering interest are presented which illustrate the influence of material properties on the stress field.
Post-Yielding Behavior of Torsionally Loaded Composite Tubes
Authors: Lantz RB , Foye RL
Published: March 2009

Using three post-yielding theories, the results of a laminate test program for in-plane shear are analyzed. In a recently completed test program at the National Aeronautics and Space Administration/Langley Research Center, 36 filament wound tubes were tested in torsion. Shear stress-strain data to the failure points were obtained for a variety of laminates. These data are compared to micromechanics, macromechanics, and quasi-linear analytical laminate predictions. Comprehensive computer codes were used to generate the analytical data. Along with the description of the correlation obtained by each method, the procedure required to implement the method is described in detail in order to identify the relative merits for each procedure.
Ultrasonic Procedures for Inspecting Composite Tubes
Authors: Rose JL , Carson JM , Leidel DJ
Published: March 2009

Ultrasonic spectroscopy is introduced as a test procedure for nondestructively evaluating composite materials. Tests reported in this study show that it is possible to locate flaw areas in a composite tube with both ultrasonic C-scan and ultrasonic spectroscopy procedures. In particular, the purpose of this paper is not to present quantitative comparisons of theoretical and experimental results of ultrasonic wave propagation in composite tubes but to indicate that frequency signatures obtained from ultrasonic spectroscopy can be useful in nondestructively evaluating composite materials. A theoretical sample problem is presented that demonstrates the sensitivity of the spectroscopy method in detecting pulse spreading. Experiments on two composite tubes are also presented to show the difference in frequency signatures that occurs when comparing flaw and no flaw areas in a structure. The major advantage of this method compared to conventional ultrasonic methods lies in its ability to detect precisely pulse dispersion and pulse location in the time domain. The frequency signature approach represents an alternative approach to standard ultrasonic pulse echo and through transmission signal analysis that often proves useful when standard methods of analysis fail because of poor resolution and lack of basic understanding and interpretation.
Determination of the Mechanical Properties of Fiber Composites by Ultrasonic Techniques.
Authors: Dean GD , Lockett FJ
Published: March 2009

A technique is described for the determination of the elastic constants of a composite specimen by measuring, in an immersion tank, the velocities of ultrasonic waves propagating in various directions in the specimen. The theoretical basis of the method, the restrictions on specimen geometry, and possible sources of inaccuracy in the measurement and interpretation of data, are all discussed. Typical results are illustrated by data for a high modulus carbon fiber reinforced epoxy. A discussion is given of the use of ultrasonic techniques for material characterization. In particular, methods are discussed for identifying and quantifying specimen homogeneity, symmetry, degree of misorientation, and defect content. Extension of the techniques to the determination of viscoelastic properties, and the associated theoretical and practical problems, is also considered.
Influence of Fiber Property Variation on Composite Failure Mechanisms
Authors: Mullin JV
Published: March 2009

This paper deals with the energy released when a fiber fails, and the local mechanisms available for energy absorption. This process is examined analytically for a linear elastic material, and the advantage of a controlled interfacial failure process is clearly indicated. Experimental observations of individual carbon fibers, having similar strain energy densities but different interfacial response, are presented. Gross fracture of tension specimens containing high fiber content is shown to correlate well with observations of individual fiber failure mechanisms. Conclusions are presented based on the analysis and experimental results.
Mechanical Property Data on Hot-Extruded 304N and 316N Stainless Steel Pipe
Authors: Kadlecek P
Published: March 2009

The effects of nitrogen in both Types 304 and 316 stainless steel were investigated on a production scale and the results are presented in this paper. The test program revealed that nitrogen had an affirmative strengthening effect on wrought austenitic stainless steels. A program establishing hot tensile, stress-rupture, creep, and fatigue data, plus welding experiments, are reported.
High-Nitrogen Austenitic Stainless Steels
Authors: Spaeder CE , Domis WF , Brickner KG
Published: March 2009

The present paper summarizes the results of a number of investigations in which the effects of nitrogen on the mechanical properties of an austenitic stainless steel were evaluated. The results of studies on commercially produced plate indicated that increasing the nitrogen content of Type 304L steel to the range 0.10 to 0.13 percent increased the room and elevated temperature strength of this steel such that its strength was equivalent to that of Type 304 steel in both the welded and unwelded condition.

The results of room and elevated temperature tension tests on product from four commercial heats of high-nitrogen (0.12 to 0.16 percent) Type 304 steel indicated that the yield and tensile strength of this steel was significantly increased. Creep-rupture tests were too limited to assess the effect of nitrogen on the creep-rupture strength of the steel. Some failures on punch marks of the creep-rupture test specimens were observed suggesting the possibility of some notch sensitivity in this steel.

The results of a limited study on laboratory heats of Type 316L containing nitrogen in the range 0.02 to 0.19 percent indicated a significant increase in the elevated temperature yield and tensile strength of this steel. The creep-rupture strength at 1300 F also increased with increasing nitrogen content.
Elevated Temperature Properties of Nitrogen-Containing Type 304L Austenitic Stainless Steel
Authors: Goodell PD , Freeman JW
Published: March 2009

Experimental heats of Type 304L steel, compositionally balanced to be wholly austenitic, were prepared to determine the influence of nitrogen on elevated temperature properties of this steel. Nitrogen is shown to increase the 1200 F (649 C) and 1350 F (732 C) yield strength slightly and to increase markedly the creep and rupture strength at 1200 F (649 C). The effect of nitrogen on creep and rupture strengths at 1350 F (732 C) and 1500 F (816 C), however, is less pronounced. A beneficial effect of nitrogen on creep and rupture properties at 1200 F (649 C) is attainable from a considerable range of heat treatments and grain sizes.
Creep and Creep-Rupture Properties of Types 304N and 316N Stainless Steels
Authors: Domis WF
Published: March 2009

If Types 304 and 316 steels with improved elevated temperature strength existed, equipment manufacturers could design to higher stresses, thereby reducing the weight and consequently the cost of fabricated equipment. The addition of nitrogen appears to be one means of improving the strength of Types 304 and 316 steels with little additional cost. Although appreciable work has been done, most of it over a limited temperature range, the effect of nitrogen on the creep and creep-rupture properties of Types 304 and 316 steels has not been quantitatively established. This paper reviews studies to determine quantitatively the effect of nitrogen on the (a) creep and creep-rupture properties of Types 304 and 316 steels within AISI composition limits over a large temperature range and (b) toughness of Types 304 and 316 steels after long time exposures at elevated temperatures.
Installation of Liquefied Natural Gas Fuel Containers and Systems on Motor Vehicles
Authors: Johnson RK
Published: March 2009

This article outlines the procedures for installation of a liquefied natural gas (LNG) system on a motor vehicle. Emphasis is placed on safety devices required in the system to minimize the hazards of LNG when used as a motor fuel.
Sensitivity and Reaction Intensity Studies of LOX-LNG Mixtures
Authors: Blackstone WR , Wenzel AB , Every RL
Published: March 2009

Mixtures of liquid oxygen (LOX) and liquid natural gas (LNG) are very attractive as commercial explosives because they exhibit very high brisance, or shattering power, and because the basic materials are readily available and inexpensive. However, the mixtures can be quite dangerous if mishandled, and there is little or no information available concerning the handling hazards. The objective of this program was to obtain such information by conducting a series of drop tests to characterize the impact ignition and reaction intensity behavior of various LOX-LNG mixtures and to determine whether the addition of an inert inhibitor would change the reaction intensity or the impact sensitivity. Impact tests were conducted using pentaerythritol tetranitrate (PETN), and the results were compared with those for the various LOX-LNG mixtures.
Polarized Crystal-Field Spectra of Micro Particles of the Moon
Authors: Mao HK , Bell PM
Published: March 2009

Polarized crystal-field spectra of individual crystals, polycrystalline aggregates, and fragments of glass from the moon reveal fundamental information on their transition elements. Specifically, the oxidation states and structural coordination of iron and titanium in lunar samples are determined by a refined technique for measuring crystal-field splitting.

The quenched states of iron and titanium in lunar crystals act as fossil indicators of the chemical history of their crystallization. Spectral and other supporting data show that the rocks and soils returned from the Apollo missions have crystallized under extremely reducing conditions, on the order of approximately 10-1 3 atm of oxygen. Lunar glasses are also chemically reduced, and the absorptions of iron and titanium cause their green and red colors and influence their albedo properties.

Measurements of the shift with pressure of crystal-field bands of divalent iron in pyroxene suggest that pressure will enhance the properties of thermal transfer by radiation. Thermal radiation could be an efficient mechanism for heat flow in the lunar interior.
Method for Ultra-Accurate Oxygen Determination for Rare Reference Samples
Authors: Volborth A , Dayal R , McGhee P , Parikh S
Published: March 2009

Lunar rocks are deficient in oxygen. In order that a meaningful analysis of oxygen could be performed on lunar, meteoritic, and terrestrial rocks a high degree of accuracy is needed. Because of the rarity of such samples the method selected has to be nondestructive.

A highly accurate fast-neutron activation method that permits nondestructive analysis of lunar, meteoritic, and terrestrial rocks is described. It consists of a dual cross-transfer system that corrects for all electronic drifts and surges as well as for neutron beam fluctuation. This method uses chemically different reference samples: silica, aluminum oxide, ferric oxide, calcium carbonate, and their carefully prepared mixtures of which infrared spectra are first taken to ascertain complete absence of water and hydroxyl groups. Accurate oxygen values are reported for six U.S. Bureau of Standards standard reference materials: opal glass, bauxite, Na-feldspar, argillaceous limestone, dolomitic limestone, and the phosphate rock; the U.S. Geological Survey biotite LP-6; and the Smithsonian Institution “AUende meteorite.”
All Electronic Magnetic Hysteresigraph
Authors: Elarde PF
Published: March 2009

Data for drawing hysteresis curves were originally obtained by the point-by-point method which was tedious and time consuming. For this reason, devices known as hysteresigraphs for drawing hysteresis curves automatically were developed. The first models did not have power to drive a recorder pen; hence, photographic techniques were used to obtain a permanent record. Later hysteresigraphs used the galvanometer photoelectric amplifier to amplify the signal and thus obtain the power necessary to drive a pen and draw a hysteresis curve directly on graph paper. For satisfactory operation, the photoelectric amplifier must be elaborately shock mounted, and adjustments and repairs require experienced personnel. The all electronic hysteresigraph eliminates many inherent disadvantages of the earlier models and makes it possible to draw a hysteresis curve in approximately one minute.
Recycling Plastics: The Problems and Potential Solutions
Authors: Mack WA
Published: March 2009

Within the last few years, significant developments have occurred which have made recycling of plastics waste materials a reality. However, before greater utilization of plastics scrap is achieved, product specifications must be rewritten which encourage greater use of recycled plastics.

This paper will present three broad classifications of plastics waste streams and the technical problems confronting recycling materials from each group. A new method of making various polymers compatible during reprocessing will be discussed. A flow diagram and cost factors will be given for a waste treatment plant which segregates solid wastes into individual components.

Costs and specifications for a new low pressure injection molding machine which molds commercially acceptable parts directly from scrap (up to 100 percent nonvirgin) will be detailed. Special attention is given to the use of the machine in fiber reclaiming, including the use of a special compacting mill necessary as an intermediate processing unit in this operation. A flow diagram for the fiber reclaiming process will be presented.
Incineration of Refuse with LOPAC Containers Added
Authors: Temple EJ
Published: March 2009

LOPAC containers, developed by Monsanto Company using high nitrile barrier polymers, are now being evaluated for the packaging of carbonated beverages: soft drinks and beer. Incineration tests were conducted as part of comprehensive public health and environmental protocol to determine the potential effects, short term and long term, of this packaging system.

The burning trials were carried out first in a large municipal incinerator, where efficient combustion conditions can be expected, and then in smaller units of the industrial and residential type, where combustion conditions may be less favorable and the percentage of beverage containers in a furnace loading may be significantly higher. Data are reported on operating conditions, smoke, odor, analysis of stack gases, effects on furnace grates, and heating values.

The results of these trials demonstrate that the portion of LOPAC containers which is not recycled may be disposed of safely in typical incinerator installations without adding to our air or soil pollution problems and without corrosive effects on the equipment used.