bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiological Emergency Response Planning
Authors: Michael EJ , Sundstrom CF
Published: March 2009

The Code of Federal Regulations, Title 10, Part 50, Appendix E—Emergency Plans for Production and Utilization Facilities—recommends that production and utilization facilities prepare emergency plans. In addition, Nuclear Regulatory Commission (NRC) Guides 1.70 (Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants) and 1.101 (Emergency Planning for Nuclear Power Plants) provide guidance for the development of Radiological Emergency Response Plans (RERP's) at both the Construction Permit stage and the Operating License stage.

This paper addresses the basic concepts of RERP and specifically discusses those RERP's which plan for incidents assumed to have both on-site and off-site consequences. It also provides insights into what has transpired at public hearings, emphasizing the importance of a coordinated effort between the facility and government agencies at all levels. In addition, it gives specific attention to the key elements that comprise an RERP and suggests some planning aids that have been developed to assist in the formulation of effective and efficient response plans. This paper also identifies many of the direct and indirect benefits of a well-developed Radiological Emergency Response Plan.
The Need for Standards of Analysis in the Nuclear Power Industry
Authors: Kelly JJ
Published: March 2009

The author reviews reported radioactive effluents from nuclear facilities in the United States to demonstrate internal inconsistencies which highlight problems in the analytical techniques used for monitoring these effluents. Specific reference is made to problems in monitoring tritium, carbon-14, radioiodines, particulates, and noble gas in these effluents. A brief description is given of an ASTM standard for tritium analysis in plant effluents and the environment and other standards under development for monitoring carbon-14, radioiodine, particulates, and noble gas in plant effluents.
New Directions in Environmental Radiological Surveillance at Commonwealth Edison's Nuclear Stations
Authors: Caldwell LS , Pavlick RA , Golden JC
Published: March 2009

In 1977 Commonwealth Edison implemented a new, two-part environmental radiological monitoring program. This program was designed to meet anticipated new regulatory requirements for greater analytical sensitivity of measurements and to implement critical pathway monitoring concepts.

Part 1—The Standard Program—monitors those environmental dose pathways which are most likely to result in human radiation exposure. The three most important pathways at light water reactors in Illinois are gamma radiation exposure from noble gases, iodine-131 in milk, and radioactivity in public drinking water from rivers and lakes. Other media included in the program at a substantially reduced frequency of sampling are fish and sediment. In addition, the environmental air samplers are maintained in event of an unplanned release. The new standard program results in a savings of approximately 50 percent of cost.

Part 2—Environmental Dose Pathway Studies—consists of projects designed to improve the environmental dose models. The projects measure environmental transfer factors for the dosimetrically important radionuclides, release values for nuclides, transfer factors for pathways that have become of increased interest recently, and numerical values to check assumptions that certain sources and pathways are insignificant contributors to population dose.

The paper describes the two parts of the monitoring program and the results of pathway studies at Zion Station—two pressurized 1050-MW water reactors.
New England States Environmental Radiation Surveillance Programs
Authors: Molloy EJ
Published: March 2009

It is the goal of this paper to provide an overview of the environmental radiation surveillance programs in the New England States from the viewpoint of their organization and administration. Moreover, this paper details the specific monitoring and analytical programs conducted at selected sites in each state with emphasis on sample types, collection frequencies, and analysis. Also, a comparison is made between the programs of all the states in order to determine the reasons for their differences.
Nuclear Regulatory Commission Region I Environmental Monitoring Inspection Program
Authors: Stohr JP , Bores RJ
Published: March 2009

The present Nuclear Regulatory Commission (NRC) organization, particularly as it pertains to the inspection program for nuclear facilities, is presented. The NRC's inspection program covering both nonradiological and radiological aspects from initial construction through the operational phase is summarized. Inspection experience, including examples of problem areas and improvements, and trends in current NRC policies relating to environmental monitoring programs are also discussed.
The Role of Field Measurements in Environmental Radiation Monitoring
Authors: Lowder WM , McLaughlin JE
Published: March 2009

The operational assessment of releases of radioactivity from nuclear facilities is performed with instruments located in or near the effluent streams or is accomplished by measuring samples collected from these streams. Direct field monitoring is relegated to a lesser role in dose assessment. The reasons for this practice include recognition that effluent measurements are more easily and rapidly performed than environmental measurements. At the same time, by regulation, detailed environmental measurements of mixed character are required around nuclear power plants. This arrangement of priorities tends to produce an unclear understanding of the objectives of field measurements and to reduce theirimportance and hence the quality of the data.

While an optimum radiation monitoring program is site-dependent, the elements of direct field measurements should include the routine deployment of thermoluminescent dosimeters (TLD's) and a few continuous “real time” monitors. Several monitors have been developed in the Environmental Measurements Laboratory and elsewhere and are undergoing field testing. The availability of field monitors provides a desirable capability for the rapid evaluation of special problems in or near the plant that arise from time to time. Moreover, such sensitive measurement methods in conjunction with meteorological data and direct effluent measurements can be employed to verify the models used for setting release limits, to calculate doses to the population around the site, and to maintain a check on effluent measurements. Improved monitoring efforts should instill greater public confidence in the facility's normal operations by detailing actual exposure data in a timely fashion.
Preparations for High-Level Defense Waste Immobilization at Savannah River Plant
Authors: Wiley JR
Published: March 2009

Methods are being developed to immobilize Savannah River Plant (SRP) wastes in high-integrity glass forms. The waste forms will be suitable for storage in an on-site facility or for shipment to an off-site repository. Alkaline wastes produced in SRP separations plants are currently stored in large, carbon-steel tanks. These wastes consist of a water-soluble fraction (salt cake and supernatant liquor) and an insoluble sludge. The water-soluble fraction contains most of the 137Cs and the insoluble sludge contains most of the 90Sr, waste actinides, and other fission products. 90Sr and l37Cs are the most hazardous radionuclides in 10-year-old waste.

A conceptual solidification process has been developed from laboratory tests with both actual and simulated waste. Engineering design studies are in progress. First, wastes are removed as a slurry from the waste tanks. The sludge is separated from the supernate, and then 137Cs is removed from the clarified supernate by ion exchange. The resulting decontaminated supernate is evaporated to a salt for bulk storage. In the second part of the process, 137Cs is mixed with sludge and the mixture is calcined and then immobilized in borosilicate glass. Off-gas from the calciner and glass melter is treated to ensure that no hazardous materials are released to the atmosphere.
Quality Assurance for Effluent and Environmental Monitoring—A Nuclear Regulatory Commission Overview
Authors: Cohen LK
Published: March 2009

This paper discusses the Nuclear Regulatory Commission's (NRC's) philosophy and approach to quality assurance (QA) for effluent and environmental monitoring. QA is considered an integral part of any comprehensive monitoring program. The NRC and other regulatory agencies are recognizing the importance of QA and are devoting more effort to incorporating QA programs into all monitoring programs. The rationale and the necessity for QA in the various monitoring programs are discussed. Current and proposed NRC quality-assurance requirements and technical specifications implementing those requirements are reviewed.

The NRC staff has developed a regulatory guide which covers generally accepted elements of QA for monitoring programs from sampling through analysis to reporting. A description of the proposed NRC Regulatory Guide 4.15, “Quality Assurance for Radiological Monitoring Programs—Effluent Streams and the Environment,” is presented.
Marinelli Beaker Calibration
Authors: Zimmer WH
Published: March 2009

The calibration of gamma spectroscopy detectors for analysis of samples in Marinelli beakers is discussed with regard to what constitutes a calibration standard and difference from a point source. Sorption effects are energy dependent and can cause errors of 20 percent or more. True coincidence summing effects can totally misalign detector efficiency, depending on the nuclides contained in the standard.
Discordant Gross Radioactivity Measurements of Natural and Treated Waters
Authors: Janzer VJ
Published: March 2009

The periodic measurement of gross radioactivity is being widely used as an indicator of the satisfactory quality of community water systems with respect to radioactivity. Requirements for these measurements were defined by the U.S. Environmental Protection Agency in Title 40, Part 141-Interim Primary Drinking Water Regulations, in the 9 July 1976 Federal Register.

Americium-241 apparently is being used by an increasing number of laboratories as an alternative gross alpha activity calibration standard in place of the recommended uranium. Higher alpha counting efficiencies obtained using 241Am result in gross alpha activity analysis differences of up to 100 percent when compared with duplicate sample analyses based on a natural uranium standard. Data presented in this report demonstrate that the use of 241Am as an alternative gross alpha calibration standard will, in effect, double the Federally specified maximum contaminant level for gross alpha activity in community water systems.

Similar problems are associated with gross beta activity calibration standards but the effects are not as pronounced. Comparative counting efficiency data for l37Cs and 90Sr/90Y as gross beta activity calibration standards are given. Gross beta activity differences of up to 25 percent may be obtained on duplicate analyses depending on the beta calibration standard used.

If gross radioactivity measurements are to be useful indicators of water quality, strict adherence to standard procedures and acceptance of single calibration standards used for determining gross radioactivity concentrations in water are needed to achieve industry-wide comparability of results.
Influence of Collector Recombination Lifetime on the Current Gain and Storage Time of High-Voltage Power Transitors
Authors: Hower PL
Published: March 2009

Two new charge control models are described that account for the effect of collector recombination on transistor current gain, hFE, and storage time, tS. For hFE it is shown that the collector lifetime, τ, is usually large enough that collector recombination can be ignored. As τ is decreased, this assumption is no longer valid, and hFE eventually becomes proportional to τ.

The lifetime is also important in determining tS at low collector currents, where tS is approximately proportional to τ. The resulting trade-off between hFE and tS is determined quantitatively for a particular example by using the proposed models.

Additional data are given that show that both models agree well with experimental measurements. The comparison is made using measured open-circuit-decay lifetimes in the theoretical calculations.
Dynamic Storage Time Measurements on Metal Oxide Semiconductor-Random Access Memory Circuits
Authors: Gosney WM
Published: March 2009

Transient capacitance measurements performed on the storage capacitors of dynamic metal oxide semiconductor (MOS) random access memory (RAM) circuits can be used to determine dynamic storage time, because the decay phenomenon is equivalent to the operation of the circuit. Therefore, transient capacitance measurements can be used as a yardstick for process improvements that lengthen storage time and improve the refresh time margin. By analyzing the transient response, using the classic Zerbst technique, the minority carrier lifetime can be determined. In addition, an extension of Heiman's theoretical analysis to include a constant contribution to the leakage currents from process-induced damage and diffusion current from the substrate gives a solution for the capacitive transient that is in excellent agreement with the experimental curves. The T and K parameters in this solution are related to the minority carrier lifetime, τ, and the constant leakage carrier generation density, g, and the values of these parameters can be determined from the Zerbst slope and intercept. For K = g = 0, the solutions reduce to those of Heiman.
Influence of Impurity-Decorated Stacking Faults on the Transient Response of Metal Oxide Semiconductor Capacitors
Authors: Ichida Y , Yanada T , Kawado S
Published: March 2009

The gettering effect of phosphorus diffusion to the back surface of a silicon wafer on oxidation-induced stacking faults has been studied by evaluating the generation lifetime from the transient response of metal oxide semiconductor (MOS) capacitors. The generation lifetime of wafers subjected to postoxidation phosphorus diffusion gettering is not remarkably decreased by the presence of stacking faults. On the other hand, the generation lifetime of waters subjected to preoxidation gettering is decreased by two orders of magnitude because of the presence of stacking faults. The result is explained by impurity precipitation to Frank partial dislocations bounding stacking faults.
Measurement and Retention of Recombination Lifetime
Authors: Blais PD , Seiler CF
Published: March 2009

The classical photoconductivity decay method for measuring recombination lifetime was improved by using a 1.06-μm pulsed laser source to generate a spacially uniform excess minority carrier concentration. The accuracy of measurements on thin wafers was significantly enhanced by using an etched, well-characterized, low recombination velocity surface in place of the normally lapped surface. Lifetime measurements were performed both before and after thermal heat treatment, and final deionized water rinsing was identified as a crucial step. A mathematic model was developed to guide the development of decontamination procedures that would optimize the retention of lifetime. Particulate contamination in the deionized water was found to be the factor limiting the post-heat-treatment lifetime.
Measurement of Minority Carrier Lifetime in Silicon Crystals by the Photoconductive Decay Technique
Authors: Gerhard AR , Pearce CW
Published: March 2009

A Nd:YAG laser was used to produce excess minority carriers in large-diameter silicon single crystals. The rate of decay of these carriers was then used as a measure of the minority carrier recombination lifetime. The high photon fluxes available from the laser made possible measurements on material of medium resistivity, generally not measureable with traditional instrumentation. The present apparatus includes: a laser light source modulated electronically, a low-noise preamplifier, and sampling and averaging instrumentation. This permits resulting signals as low as a few microvolts to be easily read and interpreted. The system has measured material ranging in lifetime from 50 to 4000 μs and represents a state-of-the-art approach to photoconductive decay measurements.
Test Facility for Material Erosion at High Temperature
Authors: Tabakoff W , Wakeman T
Published: March 2009

One of the next steps in experimental material erosion investigation is the testing at high temperatures comparable to those found inside a jet engine. Described in this paper is the design of the high-temperature erosion facility at the University of Cincinnati. This facility has the capability of providing between ambient and a 1093°C (2000°F) environment temperature for erosion testing of various materials. In addition, this facility has the capability for varying material, specimen size, angle to the flow, particle concentration, particle size, and velocity. This facility is expected to provide basic material erosion data which will be used in predicting erosion in jet engines and other devices.
Mechanisms of Erosion of a Ductile Material by Solid Particles
Authors: Maji J , Sheldon GL
Published: March 2009

Erosion of flat plates and tubular test specimens by spherical 270-μm steel shot showed appreciable differences in the amount of material removed, depending on the condition of the steel shot used. Ductile shot removed considerably less material than brittle or more frangible shot. In addition, lower-velocity exponents were obtained for the tougher, more ductile abrasive.

The evidence presented here supports the view of Tilly that erosion by frangible particles may be viewed as a two-stage process. According to this view, the first stage is due to surface indentation by the particle, forming vulnerable lips around the crater, and the second is due to removal of these lips by radially projecting particle fragments.
Calculated Tolerance of a Large Electric Utility Gas Turbine to Erosion Damage by Coal Gas Ash Particles
Authors: Menguturk M , Sverdrup EF
Published: March 2009

Erosion damage was estimated for the first stage of a large electric utility gas turbine based on projected particle distributions in the gas leaving the hot gas cleaning system of a pressurized fluidized-bed gasifier system. Based on the assumptions used in making the estimates, cleaning of the turbine expansion gas to a particulate concentration of 0.005 gram per standard cubic metre (0.002 grain per standard cubic foot) with particles larger than 6-μm diameter effectively removed should give satisfactory blade life from an erosion standpoint. Two stages of high-performance cyclone cleanup to 0.1 gram per standard cubic metre (0.5 grain per standard cubic foot) with 0.05 weight percent of 12-μm diameter particles remaining in the gas would wear stator vane trailing edges by 0.25 cm (0.1 in.) thickness (roughly equivalent to full wall thickness in upstream stage vanes) in 10000 h of operation.

The numerical results presented in this paper are based on the estimate that coal ash and sulfur sorbent particles will have, when impacting superalloy turbine materials under turbine conditions, 1/25th of the erosivity of silicon carbide particles impacting a nickel alloy at room temperature. The estimates do not account for the appreciable slowing of the 1- to 3-μm particles in the blade boundary layers before they reach the blading, even though these small particles account for most of the damage. The numerical results are in this way conservative. Actual data on the damage which coal gas particulates do to blade materials under turbine conditions are needed to establish the erosion tolerance of the turbine more accurately.
Damage Mechanisms in Polymers and Composites Under High-Velocity Liquid Impact
Authors: Gorham DA , Matthewson MJ , Field JE
Published: March 2009

This paper presents results from recent liquid impact studies of a variety of glass and carbon fiber reinforced and nonreinforced thermoplastic and thermosetting polymers. Basic damage modes from single impacts in the velocity range 500 to 1000 m s-1 are described and the mechanisms of failure are analyzed. The thermosetting resins studied are essentially brittle, in contrast to the very ductile thermoplastics, and these fundamental differences are emphasized when fibrous reinforcement is added. The effects of matrix properties, reinforcement geometry, the condition of the impacted surface, and impact angle are illustrated and discussed. The main conclusion is that, although no ideal solution exists to withstand all impact situations, it is possible to establish general rules which assist in the design of composites for specific purposes. In particular, reinforced thermoplastic resins are found to have considerable advantages over reinforced thermosetting resins for many practical situations, particularly when the postimpact material strength needs to be maximized.
Effect of an Air-Injected Shroud on the Breakup Length of a High-Velocity Waterjet
Authors: Eddingfield DL , Albrecht M
Published: March 2009

Air-injected shrouds are used to create an airflow parallel to a high-speed waterjet to examine the effect of the air velocity on the breakup length of the waterjet. Eight shrouds having four different lengths and two different diameters are employed in this study. The air velocity was varied from zero to approximately twice the velocity of the waterjet. The waterjet has an exit diameter of 0.766 mm (0.030 in.) and an exit velocity of 266 m/s (874 ft/s) for all the experimental runs.

Of the shrouds tested, the shortest shroud with the smaller diameter produced the best results for the entire air velocity ranges. The breakup length of the waterjet with a shroud compared to that of a waterjet without a shroud ranges from 1.2 for an air-to-water velocity ratio of zero up to a value of approximately 1.7 for a velocity ratio of 2.0.

Cutting tests on a representative material are planned to establish firmly the benefit of utilizing an air-injected shroud in conjunction with a high-velocity waterjet.
Use of High-Pressure Waterjets in Utility Industry Applications
Authors: Huszarik FA , Reichman JM , Cheung JB
Published: March 2009

During the past several years, waterjets with pressures up to 408 MPa have become a reliable tool for industry and have been used for a variety of factory applications. In addition, waterjets have been tested for rock cutting in mining and tunnel applications. The utility industries do a considerable amount of work that requires excavation in rock and concrete. The potential of using high-pressure waterjets to meet their field needs has been considered. To date, the telephone, electrical power, and gas industries have conducted studies on the use of high-pressure waterjets. This paper contains descriptions of the various applications of waterjets in the utility industry, descriptions of the appropriate equipment and cutting techniques, discussions of some possible systems and their operating parameters, and an economic analysis of waterjet methods for trenching and pole-hole drilling.

A study was conducted to examine the use of waterjets in utility industry applications. The study was a three-phase program. In the first phase, the possible applications and their significance to utility company operations were examined. In the second phase, a strategy for cutting rock and concrete with waterjets as well as a conceptual system design was developed. Various rock types were tested, and rates were predicted for two specific applications: trenching and pole-hole drilling. In the third phase an economic analysis of the cost of using waterjet methods for trenching and pole-hole drilling was performed and costs were compared with current methods on a per-hole or per-foot of trench basis. In addition, the advantages and disadvantages of waterjet methods on a system basis were compared with those of existing methods.

The study has demonstrated that there is a wide variety of applications for high-pressure waterjets in the utility industry. The study further shows that waterjet devices are both technically and economically feasible. The predicted rates and the costs indicate that, in rock, the waterjet system is better than current methods.

A detailed overview of this study as well as the results are presented in this paper.
Stability Analysis of J-Controlled Crack Growth
Authors: Hutchinson JW , Paris PC
Published: March 2009

The theoretical basis for use of the J-integral in crack growth analysis is discussed and conditions for J-controlled growth are obtained. Calculations related to the stability of crack growth are carried out for several deeply cracked specimen configurations. Relatively simple formulas are obtained which, in certain cases, permit an assessment of stability using data from a single load-displacement record. Numerical results for a bend specimen and for a center-cracked specimen illustrate the influence of strain-hardening and system compliance on stability.
A Numerical Investigation of Plane Strain Stable Crack Growth Under Small-Scale Yielding Conditions
Authors: Sorensen EP
Published: March 2009

Plane strain crack advance under small-scale yielding conditions in elastic-perfectly plastic and power-law hardening materials is investigated numerically via the finite element method. Results indicate that the stress distribution ahead of a growing crack is essentially the same as that ahead of a stationary crack, and that the numerically evaluated steady-state crack tip profiles reflect a vertical tangent at the extending crack tip which corresponds to the theoretically predicted outline. It is found that the increment dδt in crack tip opening, when loads are increased at fixed crack length, seems to be uniquely related to dJ/σo irrespective of the amount of previous crack growth, and for increments dl of crack advance at constant external load, the incremental crack tip opening appears related to ln (J/σor) dl when evaluated at distance r from the tip. A discussion of proposed fracture parameters for continued crack growth (as opposed to growth initiation) is included.
Initial Experimental Investigation of Tearing Instability Theory
Authors: Paris PC , Tada H , Ernst H , Zahoor A
Published: March 2009

An initial experimental investigation was conducted to confirm the theory of tearing instability developed in previous work. A simple testing program was selected which employed 3-point bend specimens with various crack size to specimen depth ratios and an additional spring bar to easily adjust effective specimen span (or loading system compliance).

All stable-unstable behaviors observed in the tests are in good agreement with those predicted by the theory. Thus the present study demonstrates the appropriateness of the tearing instability analysis, presenting guidelines for its further development.
J-Integral Determinations and Analyses for Small Test Specimens and Their Usefulness for Estimating Fracture Toughness
Authors: Royer J , Tissot JM , Pelissier-Tanon A , Le Poac P , Miannay D
Published: March 2009

General estimation procedures for the J-integral determination are reviewed for the three-point bend and the compact tension specimens. Tests were made using 10 CD 9–10 steel. Experimental results are presented and are in partial agreement with analytical results. The errors due to simplified analysis and experimental procedure are explored. Toughness, as analyzed by the resistance curve technique, is shown to be size dependent for bending and not for tension. Disagreement between the two loading modes, if not fortuitous and due to the steel, suggests that simple strain and stress analyses are not sufficient and that the loading procedure and the T-effect must be taken into account.
Minimum Specimen Size for the Application of Linear-Elastic Fracture Mechanics
Authors: Munz D
Published: March 2009

The minimum thickness and the minimum ligaent width for the determination of plane-strain fracture toughness with linear-elastic methods can be considerably smaller than given by the ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-74). For the ligament width, the factor 2.5 in the size requirement equation can be replaced at least by 1, possibly by 0.4. The size dependence of KQ determined with the 5 percent secant method is due to plasticity at the crack tip and to the existence of a rising plane-strain crack growth resistance curve. With a variable secant, adjusted to the specimen width, it is possible to determine size-independent fracture toughness values.
Thickness and Side-Groove Effects on J- and δ-Resistance Curves for A533-B Steel at 93°C
Authors: Andrews WR , Shih CF
Published: March 2009

A test program was conducted to determine the effects of specimen thickness variations, side grooves, and crack length variations on the deformation and ductile fracture of A533-B, Cl-1 steel at 93°C.

The crack extensions were estimated using the correlation between elastic compliance and crack length. Crack extensions were also estimated using a correlation among crack-opening displacements, load line displacements (δ - VL), and crack length. The inferred estimates of crack extension were supplemented by some measurements on heat-tinted fracture surfaces. The results suggest that the observation of thickness or side-groove effects on crack-extension resistance curves is dependent on the method of measuring crack extension.

The compliance correlation method was less sensitive to crack extension and showed a classical thickness effect: increased crack growth resistance with decreasing thickness, and decreased resistance with the use of side grooves. The δ - VL correlation method was more sensitive to crack extension and showed no effect of thickness or of side grooves on crack growth resistance. The presence of side grooves promoted flat fracture and suppressed shear lips. Specimens without side grooves developed large shear lips.
Dynamic Fracture Toughness of ASME SA508 Class 2a Base and Heat-Affected-Zone Material
Authors: Logsdon WA
Published: March 2009

The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code requires that dynamic fracture toughness data be developed for materials with specified minimum yield strengths greater than 345 MPa (50 ksi) to provide verification and utilization of the ASME specified minimum reference toughness KIR curve. In order to qualify ASME SA508 Cl 2a pressure vessel steel [minimum yield strength equals 450 MPa (65 ksi)] per this requirement, dynamic fracture toughness tests were performed on three heats of base and heat-affected-zone (HAZ) material from both automatic and manual submerged-arc weldments. Linear elastic KId results were obtained at low temperatures while J-integral techniques were utilized to evaluate dynamic fracture toughness over the transition and upper shelf temperature ranges. Loading rates in terms of K were on the order of 2.2 to 4.4 × 104 MPam/s (2 to 4 × 104 ksiin./s). Tensile, Charpy impact, and drop weight nil ductility transition (NDT) tests were also performed. All dynamic fracture toughness values of SA508 Cl 2a base and HAZ material exceeded the ASME specified minimum reference toughness KIR curve. Upper shelf temperature resistance curves obtained by the standard multiple-specimen J test technique, where each specimen was loaded dynamically to a specific displacement, and resistance curves obtained via specimens loaded dynamically to failure, yielded essentially identical JId values.
Fracture Behavior of Stainless Steel
Authors: Bamford WH , Bush AJ
Published: March 2009

An experimental program has been carried out to characterize the fracture properties of austenitic stainless steel piping and plate material. Characterization was in terms of the J-integral, and several specimen types were tested, including compact specimens, center-cracked panels, and three-point bend specimens.

Several methods of monitoring crack extension were used in the program, including unloading compliance, electrical potential, and acoustic emission in addition to the multiple-specimen heat tinting method used for baseline data. These methods are compared and evaluated in detail.

In addition to determining JIc values for the material, Paris's proposed tearing modulus is evaluated, and various proposed specimen size requirements are discussed.
Correlation of Structural Steel Fractures Involving Massive Plasticity
Authors: Macdonald BD
Published: March 2009

A three-dimensional, elastic-plastic fracture strength correlation for A36 and HSLA structural steel connections containing discontinuities was determined. The fracture specimens comprised beam-column connections in which one column flange contained a mid-thickness plane of discontinuity. Beam loading or direct tension applied normal to the column face imposed tensile load transfer around the boundaries of the discontinuity. Fracture extension was mixed mode (crack opening and edge sliding), and inclined toward the free surface on the web side of the column flange containing the discontinuity. Successful correlation for these specimens was accomplished with a plastic stress singularity strength model, if the discontinuity was sufficiently large. The average singularity strengths at ultimate load were 64.6 MNm -3/2 (58.7 ksi in.1/2) for HSLA steels, and 53.7 MNm -3/2 (48.8 ksi in.1/2) for A36 steel. The percent coefficient of variation was 6.4 percent for HSLA steels and 8.4 percent for A36 steel.
An Approximate Method of Elastic-Plastic Fracture Analysis for Nozzle Corner Cracks
Authors: Merkle JG
Published: March 2009

Two intermediate test vessels with inside nozzle corner cracks have been pressurized to failure at Oak Ridge National Laboratory (ORNL) by the Heavy Section Steel Technology (HSST) Program. Vessel V-5 leaked without fracturing at 88°C (190°F), and Vessel V-9 failed by fast fracture at 24°C (75°F) as expected. The nozzle corner failure strains were 6.5 and 8.4 percent, both considerably greater than pretest plane-strain estimates. The inside nozzle corner tangential strains were negative, implying transverse contraction along the crack front. Therefore, both vessels were reanalyzed, considering the effects of partial transverse restraint by means of the Irwin βIc formula. In addition, it was found possible to accurately estimate the nozzle corner pressure-strain curve by either of two semi-empirical equations, both of which agree with the elastic and fully plastic behavior of the vessels. Calculations of failure strain and fracture toughness corresponding to the measured final strain and flaw size are made for both vessels, and the results agree well with the measured values.
Use of a Compact-Type Strip Specimen for Fatigue Crack Growth Rate Testing in the High-Rate Regime
Authors: Mowbray DF
Published: March 2009

Fatigue crack growth in chromium-molybdenum-vanadium steel was studied in the high-rate regime of 2.5 × 10-4 to 2.5 × 10-1 mm/cycle with a compact-type strip specimen. The specimen was found to give rise to constant growth rates over large increments of crack length when cycled under simple load control. Use of the crack opening load ranges and an approximate J-integral analysis showed that the growth was occurring under essentially constant ΔJ.
Use of AIDS Recorded Data for Assessing Service Load Experience
Authors: de Jonge JB , Spiekhout DJ
Published: March 2009

Inspection periods and safe service lives of transport aircraft are based on an assumed average design load experience. Actual service loads may deviate appreciably from these assumptions.

Fatigue related load data may be obtained on a routine basis from AIDS-recordings. The importance of careful data quality checking is stressed.

Examples illustrate the highly relevant information with regard to aircraft usage and loading environment that may be obtained.
Overview of the C-5A Service Loads Recording Program
Authors: Stone WJ , Stanley AM , Tyson MJ , Kimberly WH
Published: March 2009

The United States Air Force (USAF) C-5A Service Loads Recording Program (SLRP) was initiated in the early 1970s to acquire in-service data in sufficient quantity to define the operational environment of an “average” C-5A and to develop repeated loads (stress) spectra for applications in loads and fatigue analyses. Instrumentation was installed on 26 airplanes to record up to 53 different data parameters on magnetic tape by means of the C-5A MADARS recorder. Over 9000 h of usable operational data were acquired in the course of the program. Using these measured data along with current analytical data for wing stresses, airplane vertical acceleration, and other responses, analyses were conducted for 13 different load sources. The results were new criteria and modified analytical wing loads which were used in the design phase of the C-5A Wing Modification Program and in the updating of service life predictions made by the C-5A Individual Aircraft Service Life Monitoring Program.
Highlights of the C-141 Service Life Monitoring Program
Authors: Morcock DS
Published: March 2009

271 C-141A and 1 YC-141B Lockheed Starlifter cargo transport airplanes are presently in the United States Air Force (USAF) Military Airlift Command (MAC) inventory. The C-141A program includes all elements of the Aircraft Structural Integrity Program (ASIP) defined in Military Standard MIL-STD-1530 (USAF), “Aircraft Structural Integrity Program, Airplane Requirements”, 1 Sept. 1972. The purpose of this paper is to present highlights of the C-141A service life monitoring program.
Long Life Random Fatigue Behavior of Notched Specimens in Service, in Service Duplication Tests, and in Program Tests
Authors: Gassner E , Lipp W
Published: March 2009

The actual service fatigue life of notched steel and aluminum specimens was determined using a special testing device installed in a passenger car and operated by the vertical displacements of a car rear wheel; the specimens are subjected to reversed bending. The tests were carried out over a distance of more than 2 × 105 km. The testing device was equipped with counting instrumentation to ensure direct correlation between the individual test result and the relevant frequency distribution of level-crossings.

The results of the service test series are statistically evaluated and presented as stress/life curves for SAE 5140 and for 2024 T 3 specimens. The corresponding stress/life curves, obtained in service duplication tests were not significantly different.

However, the conventional eight-step program tests overestimate the fatigue life observed in service and service duplication tests by a factor which may be as high as five.

The results of the test series were also compared to fatigue calculations. It was found that the application of a modified linear fatigue damage rule, which does not account for the sequence effect of load changes, yielded fatigue life data which are very much on the nonconservative side. This confirmed the now generally accepted fact that valid fatigue life prediction models must account for the sequence of individual peaks and troughs.
Orthopedic Implant Retrieval and Analysis Study
Authors: Weinstein AM , Spires WP , Klawitter JJ , Clemow AJT , Edmunds JO
Published: March 2009

The incidence and degree of corrosion of a series of Type 316L stainless steel orthopedic internal fixation devices has been investigated. A complete metallurgical analysis and clinical analysis was performed for each case. Seventeen devices were studied, consisting of a total of 91 components, of which in excess of 95 percent exhibited either fretting or crevice corrosion or a combination of both. This localized attack was observed in all cases. A corrosion index was defined for each component, and this was related to the length of time in situ and to the clinical reason for removal of the device. No correlation between degree of corrosion and time in situ was observed. Crevice and fretting corrosion were found to be two separate mechanisms, but may act simultaneously and are often indistinguishable from each other at low magnifications.
Crevice Corrosion of Implant Alloys—A Comparison of In-Vitro and In-Vivo Studies
Authors: Syrett BC , Davis EE
Published: March 2009

As part of a program to evaluate a family of high-strength, high-ductility stainless steels (TRIP steels) for use in orthopedic implants, the crevice corrosion resistance of one of these steels (containing 4 percent molybdenum) was compared with the resistances of two alloys in current clinical use (Type 316L stainless steel and cast Vitallium alloy). The three materials were subjected to two types of in-vitro test and two types of in-vivo tests. In one in-vitro test, two-plate crevice assemblies of each material were weighed before and after a nine-month period of immersion in a physiological saline solution; concurrent potential measurements were made on noncreviced specimens. A rapid in-vitro electrochemical technique, called the PPR test, was used to determine crevice corrosion (or pitting) propagation rates and the potential, Eprot, below which crevice corrosion (or pitting) cannot occur. By comparing Eprot values with the long-term corrosion potentials, it was possible to predict the relative susceptibilities of the alloys to crevice corrosion. In one in-vivo test, bone/metal crevices were produced by inserting small cylindrical coupons of each alloy into holes drilled into the femurs of six mongrel dogs. In the other in-vivo test, bone plates of each alloy were fixed with mating screws to each humerus and to each femur of four rhesus monkeys: this type of specimen provided metal/metal and metal/bone crevices and most closely simulated expected service conditions. The cylindrical coupons, the bone plates, and the tissue surrounding each specimen were examined after exposure times of up to two years. The results of the two in-vitro tests and of the in-vivo tests in rhesus monkeys were entirely consistent: each test indicated that the TRIP steel is fairly susceptible to crevice corrosion, that Type 316L staineiss steel has limited susceptibility, and that cast Vitallium alloy is essentially immune to this form of localized corrosion. However, all alloys were much more resistant to crevice corrosion when implanted into dog bone, and the TRIP steel performed as well as the Type 316L stainless steel, though not as well as the cast Vitallium alloy. Thus, although we have demonstrated that it is possible to obtain good agreement between in-vitro and some in-vivo tests, the inconsistencies in the in-vivo results underline the need for a reevaluation of the animals and the in-vivo test techniques commonly used for assessing the suitability of candidate implant materials.
Application of Electrochemical Techniques to Characterize the Corrosion of Dental Alloys
Authors: Sarkar NK , Fuys RA , Stanford JW
Published: March 2009

Electrochemical techniques involving potentiostatic and potentiodynamic (hysteresis) polarization have been employed to evaluate the corrosion resistance of dental amalgams and dental casting alloys in a 1.0 percent sodium chloride solution, Unlike conventional dental amalgams, where corrosion is associated mainly with the presence of the tin-mercury (γ2) phase, the corrosion of γ2-free dental amalgams results from the presence of silver-copper eutectic or copper-tin or both. The corrosion of silver-base and gold-base dental casting alloys stems from the presence of silver-rich microsegregations with a possible minor contribution from a copper-rich phase. These results agree with the results obtained from long-term laboratory and clinical studies and thus demonstrate the usefulness of relatively quick, convenient electrochemical techniques in the evaluation of the corrosion resistance of dental alloys.
Degradation of Amalgam Restorations In Vivo
Authors: Espevik S , Mjör IA
Published: March 2009

Amalgam restorations, of known history and alloy type, which had been in service for two and a half to three years were replaced because of marginal deterioration. The restorations were carefully removed to preserve the structural details, including the deteriorated margins, and examined metallographically. The results indicated that three types of corrosion prevailed, A uniform type of attack was observed on interproximal areas with a layer of corrosion products consisting of tin oxide chlorides. A second type of corrosion was found to be corrosion of the γ2 phase, internally in the amalgam. Thirdly, cracks and intergranular corrosions were observed in areas of stress, which suggested that a stress corrosion type of attack can be responsible for marginal breakdown of amalgam restorations.
A Unifying Theory for Determining Human Response to Sound
Authors: Higgins TH
Published: March 2009

In the following work, the relationship between the perceived level of sound (loudness or noisiness) (PLdB) is shown to be a function of the sound pressure (p) squared and the sound frequency (f) squared; that is, PLdB = 10 log (25 p2 f2) in the psychoacoustically important low frequency range up to 4000 Hz. The perceived level of an aircraft takeoff or landing is demonstrated to be equal to the logarithmic sum of the peak perceived levels calculated for each one-third octave band. Effective perceived level (EPLdB) may be calculated by using the procedures contained in the Federal Air Regulations (FAR), Part 36, to correct for the duration of the sound 10 dB below peak level. PLdB and EPLdB show the highest relationship between subject ratings and the physical characteristics of the flyover sounds accounted for by any calculation procedure.

The average rate of growth of annoyance (loudness or noisiness) for a diverse mix of aircraft operations ranging from low to high power levels is shown to be a function of log (k pf)½ for the low frequencies which propagate over long distances with relatively small power loss.

The results are found to be accurate in the useful range of sound pressure levels and frequencies associated with operational aircraft including helicopters, turbofan, turboprop and turbojet powered aircraft. This work, therefore, provides the systems engineer with an easily understood and useful design and evaluation method. The formula developed clearly shows the design engineer and management personnel the relationship between the physical characteristics of an evolving system and its potential impact on human and community response.