bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of Optical and Mechanical Properties of Heavy-Metal Fluoride Glasses
Authors: Bendow B , Burge DK , Bennett HE , Johnston LH , Mecholsky JJ
Published: December 2008

Heavy-metal fluoride (HMF) glasses are promising materials for many infrared (IR) components such as laser windows, missile domes, lenses, filters, and optical fibers. In this paper we report the results of studies of optical and mechanical properties of representative HMF glass samples (including fluorozirconates, rare-earth fluoride glasses, and transition metal fluoride glasses) obtained from a variety of government, academic, and commercial sources. Quantities measured include IR absorption and emission, total integrated scatter (TIS), fracture toughness, and thermal stress resistance. The glasses studied displayed smooth multiphonon edges with absorption coefficients in cm−1 reaching unity in the vicinity of 7 μm and becoming as low as 4 × 10−3 cm−1 at DF wavelengths. Thermal emittance measurements indicate that the absorption edge moves relatively little with increasing temperature. TIS values in the infrared were as low as a few parts in 104 and the fracture toughness was about one-third to one-half that of fused silica. Rapid heating studies performed on a representative HMF composition indicated that there was no degradation in strength even up to the melting point.
Optical and Mechanical Properties of Water Clear ZnS
Authors: Harris RJ , Graves GA , Dempsey DV , Greason PR , Gangl ME , O'Quinn DB , Lefebvre MJ
Published: December 2008

Optical and mechanical properties of water clear ZnS produced by CVD, Inc. of Woburn, MA, have been measured. These include optical absorption at several laser wavelengths, spectral transmission, thermo-optic coefficients, stress-optic coefficients, thermal expansion coefficient, density, specific heat, thermal diffusivity, and electrical resistivity. Measurements were made on production grade material and three research batches and correlations made for optical properties as a function of deposition parameters.
Increase in the Optical Damage Threshold of Cellulose Acetate
Authors: Acharekar MA
Published: December 2008

Passive Q-switches manufactured with cellulose acetate are generally used in portable/handheld Nd:YAG laser rangefinders. The advantages of this type of Q-switch device are small size, economy and simplicity of operation. However, the limitation of this type of passive Q-switch is its low damage threshold.

For Nd:YAG laser, Bis (4-Dimethyaminodithiobenzil) Nickel dye is generally doped in 0.125 to 0.250 mm thick sheets of cellulose acetate material. Bis-Nickel dye in a cellulose acetate host, when inserted in a Nd:YAG laser resonator and exposed to 1.06 micron radiation, saturates and bleaches giving a giant Q-switch pulse.[1] Commercially available[2] cellulose acetate sheets of this passive Q-switch suffer permanent optical damage when operated at 20 mJ output energy in a 20 ns pulse width at 10 Hz repetition rate. To improve the damage threshold of the passive Q-switch, a process for improving transmission and optical properties (voids, inclusions, etc.) of the host cellulose acetate was developed. The details of the process will be discussed and the damage measurement data collected will be presented.
The Effects of Slope Error on the Imaging Quality of a Mirror as the Ratio of Surface Perturbation Depth to Wavelength Approaches Zero
Authors: Bennett HE , Burge DK
Published: December 2008

Three parameters are needed to specify the quality of a polished mirror surface: (1) optical figure tolerance, (2) surface microroughness and scratch/dig specification, and (3) slope error. The slope error is a measure of surface ripple, i.e., long-range modulations or zones with wavelengths typically in the centimeter to tens-of-centimeters range. The increase in blur circle diameter and resulting decrease in resolution caused by slope error can normally be computed from geometrical optics, since the surface wavelength is much longer than the wavelength of incident radiation. However, as the depth of the surface perturbation becomes small compared to the optical wavelength (as may occur, for example, in going from the visible to the infrared), geometrical optics no longer applies and the effects of slope error are greatly reduced. A comparison of physical and geometrical optics calculations of the effect of slope error in this limiting case will be given.
A Fundamental Approach Towards Improved Optical Coatings
Authors: Lewis KL , Savage JA
Published: December 2008

The potential afforded by molecular beam epitaxy as a means of producing thin film materials in a highly controlled manner has been exploited using an ultra-high vacuum facility dedicated to the examination of all facets of thin-film technology as applied to optical coatings. The equipment allows deposition on ion-beam cleaned substrates either from molecular beams or by RF sputtering, and allows in situ characterisation by mass spectrometry, Auger Electron Spectroscopy and laser calorimetry. Application of the equipment is described with reference to the fabrication of ZnSe coatings. The composition of the residual atmosphere within the coating chamber is discussed with reference to the rate of adsorption of impurities onto the substrate whilst growth of the coating is underway. By ensuring the reduction of the partial pressures of water vapour and carbon monoxide to the low 10−10 mbar range, ZnSe films have been produced of up to 3 μm in thickness which have negligible values of absorptance at 10.6 μm. Such layers, although micro-polycrystalline, are mirror smooth and featureless, and of (111) orientation. Growth rates in excess of 1 μm/h are comparable with conventional coating techniques.
A Wide Spectrum Antireflective Coating for Silica Optics and its Damage Resistance at 350 nm
Authors: Yoldas BE , Partlow DP , Smith HD
Published: December 2008

A wide-spectrum antireflective coating has been developed for fused-silica optics. This coating provides antireflectivity down to ∼300 nm on fused silica, increasing its transmission to better than 99%. The coating is a single-layer graded-index film applied from special polymer-oxide solutions. The graded index results from nonscattering porosity and tailoring of the pore morphology. Unlike state-of-the-art techniques, however, the method does not involve phase-separated glasses, not does it require etching for the creation of porosity. The damage thresholds of coated fused silica optics at 350 nm initially varied from less than 1 J/cm2 to 9 J/cm2. The main causes of this large variation in the damage threshold were investigated and determined to be substrate polishing, substrate surface cleaning, and coating solution chemistry and processing which, under certain conditions, leads to carbon formation during the heat treatment of the coating.
“A Comprehensive Analytical Theory for Unifying Pulsed and Continuous Wave Laser Damage on Metal Mirrors, Encompassing the Relationship of Small Spot to Large Spot Size Damage on Metal Mirrors.”
Authors: Palmer JR
Published: December 2008

A theoretical model has been developed which provides for evaluating both pulse and continuous wave laser damage on metal mirrors. The model technique employs the three-dimensional Palmer-Bannett model as a base. Using the fullwidth, half-band temporal profile for the pulse time constant and the thermal diffusivity of copper as a baseline, the time constant is corrected for other materials by the ratio of thermal diffusivities.

Basically, the theoretical concept rests on the premise that neither the Drude theory nor the Jakob-Kelvin theory are completely correct for short-pulsed (i.e., less than a microsecond) time constants. The heat sink below the first few angstroms acts as a dampening coefficient. The metal does not appear to be able to respond to the very short time constants and, as a consequence, the temperature versus reflectivity does not hold in straight-forward fashion. As the time constants extend into the microsecond regime, and longer, the relationships of temperature versus reflectivity become more representative.

Melt and Slip thresholds for copper, silver and gold have been presented previously [1]. The data have been generated for wavelengths of 1.06 μm, 2.7 μm, 3.8 μm, and 10.6 μm. Varying spot-sizes and different pulse widths were used. The theoretical model has been applied against this datum with excellent results ranging from 99.8% to 82% agreement.

Based on the relationship suggested by the three-dimensional Palmer-Bennett model and the unifying theory suggested, spot size dependence may be determined for given metal diamond turned mirror substrates.

The basis for damage, selected for the theory, is the point where slip phenomena occurs in the metal surface. This selection is more than arbitrary. Slip phenomena becomes the first indication that there is a permanent disruption to the optical surface. Further, slip and melt would seem to be the most thermally dependent manifestations of disruption.
Toxicity Testing with Constant or Decreasing Concentrations of Chemically Dispersed Oil
Authors: Anderson JW , Kiesser SL , McQuerry DL , Riley RG , Fleischmann ML
Published: December 2008

An exposure system and method of quantitating toxicity have been developed to provide an estimate of the effects of dispersed oil on marine organisms under a variety of exposure conditions. Results of constant concentration exposures (for hours or days) can be compared to those of diluting exposures (decreasing to zero in 8 or 24 h) on a basis of the “toxicity index.” This index is equal to the total exposure when time in hours or days is multiplied by the concentration at each hour (ppm · h or ppm · days). Tests have been conducted with shrimp (Pandalus danae), two oils (Prudhoe Bay crude and a light Arabian crude), and two dispersants. There is a seasonal pattern to the tolerance of the shrimp. Tests in the colder months (fall/winter) produce toxicity indices approximately three times higher than summer/spring values. Testing shrimp with Prudhoe Bay crude oil and a chemical dispersant during the fall/winter season, we found constant and 24-h dilution exposures produced toxicity indices of 11 (±1.1 standard error) and 10 (±0.6 standard error) ppm · days, respectively. During the fall/winter season (greatest tolerance), tests with Prudhoe Bay crude and two different chemical dispersants produced toxicity indices for P. danae of 10 (±0.6) and 12 (±1.1) ppm · days. During tests in summer, there was also little difference observed when the toxicity of the light Arabian oil was compared to that of Prudhoe Bay crude (2.3 and 3.4 ppm · days, respectively). The usefulness of our methods is that in addition to the comparisons already noted, it is possible to predict the outcome of dispersant application under varying environmental conditions.
Uniform Methods for Exposure Regimes in Aquatic Toxicology Experiments with Chemically Dispersed Oils
Authors: Wells PG , Anderson JW , Mackay D
Published: December 2008

Many different approaches have been used recently in aquatic toxicity research for preparing and analyzing test solutions and dispersions of hydrocarbons. dispersants, hydrocarbon/dispersant mixtures, and oiled sediment mixtures. This variety is a result of the novelty of this research field. Therefore much of the published work is difficult to compare, summarize, and interpret. Both uniform and unique methods will contribute to a better understanding of the toxicology and potential field effects of chemically dispersed oils in marine waters. This paper summarizes some current methods and recommends adoption of certain principles and uniform methods for water and sediment studies. Specific items discussed are (1) choice of oils and dispersants; (2) degree of “weathering” of the experimental oils; (3) preparation of water-soluble fractions and oil dispersions in water; (4) choice of dispersant/oil ratios, especially considering dispersant effectiveness; (5) reagent mixing and premixing; (6) dosing of sediments; (7) chemical analysis of dispersed hydrocarbons; and (8) choice of exposure concentrations, composition, and durations. This paper is intended to encourage more uniformity in test conditions. This need for uniformity has been recognized internationally for several years.
A Review of the Relationship Between the Characteristics of Spilled Oil and Dispersant Effectiveness
Authors: Canevari GP
Published: December 2008

The effectiveness of a particular chemical dispersant is usually determined by various laboratory tests. Such laboratory performance cannot always be replicated in the field. The physical and chemical aspects of the actually spilled oil influence dispersant performance in a manner that usually cannot be extrapolated from the laboratory tests. Some of the important parameters discussed in this paper are the geometry, viscosity, and lens effect of the slick and the type of crude oil. Very thin slicks are sometimes not truly dispersed but are collected into a multiplicity of surface lenses by the penetration of the relatively large dispersant droplet. Heavily weathered and very viscous oil can resist contact with the more fluid dispersant and dispersant “roll-off” can ensue. An oil slick wherein 90% of the oil can be located in 10% of the area could result in overtreating some areas and undertreating others. The composition of the crude oil and its emulsion-forming tendency influence dispersant effectiveness regardless of other physical properties such as viscosity. This influence is more extensively discussed because of the unique effect of the crude oil composition on dispersant effectiveness.
An Evaluation Program for Aerially Applied Dispersants
Authors: Gill SD
Published: December 2008

The Canadian Offshore Aerial Applications Task Force (COAATF) was convened in 1979 to conduct laboratory and field studies on the practical effectiveness of the aerial application of oil spill dispersant concentrates under Canadian environmental conditions. Several studies undertaken by COAATF are briefly reviewed with regard to their contribution towards this objective.
The Effects of Dispersants on Incorporation of Volatile Liquid Hydrocarbons into the Water Column
Authors: McDonald TJ , Brooks JM , Kennicutt MC
Published: December 2008

A study was conducted to assess the effect of dispersants on the incorporation of volatile liquid hydrocarbons (C5-C14) into the water column from surface oil slicks. A laboratory tank was used to vary a number of parameters including oil type, dispersant type, time of dispersant application, wind speed, and temperature. Water samples removed from an underwater sampling port indicated that the light aromatics (e.g., benzene to xylene) were the dominant compounds introduced into the water from dispersed oil. At lower temperatures a decreased amount of volatile liquid hydrocarbons (VLH) was incorporated into the water column because of the lower solubility. Wind speed had little effect on the amount of VLH incorporated into the water column within the experimental design. The chemical and physical properties of the oil exerted important influences on the type and concentration of VLH detected in the water column. The more viscous the oil, the less the dissolution of VLH. Immediate application of dispersant introduced the greatest amount of VLH into the water column. If the oil was weathered for 24 h only small amounts of VLH were incorporated into the water column. A comparison of dispersants Corexit® 9527 and 7664 indicated that 9527 was most effective in accelerating VLH incorporation into the water column.
A Proposed Cooperative Program on Statistical Ecology and Environmental Statistics for Increased Resource Productivity and Environmental Protection and the Panel Discussion at the ASTM Symposium on Statistics in the Environmental Sciences
Authors: Patil GP
Published: December 2008

The ASTM Symposium on Statistics in Environmental Sciences appeared to be an appropriate forum for an effective dialogue for agencies, industries, and academia to do something together that should be timely, fruitful, and synergistic. A panel discussion on a much needed cooperative program on statistical ecology and environmental statistics for increased resource productivity and environmental protection was organized for the morning of the second day of the symposium program. The present article is especially prepared to report on the session with multifaceted discussion for the benefit of the wider readership.

The proposed cooperative program considers formulation of prototype and experimental programs, such as, cooperative centers for statistical ecology and environmental statistics to conduct collaborative research on contemporary quantitative studies and issues in statistical ecology and environmental statistics involving scientific and public policy research. The proposed cooperative program also needs to formulate mechanisms for effective communication and continuing dialogue, such as, a quarterly scientific newsletter, timely symposia and workshops, satellite courses, and conferences with emphasis on contemporary quantitative studies and issues in statistical ecology and environmental statistics.
What is Quality Assurance?
Authors: Taylor JK
Published: December 2008

The quality of data must be known and established before it can be used logically in any application. Data quality may be judged on the basis of its quantiative accuracy and on the confidence that can be placed in the qualitative identification of the parameters measured. This requires the production of data in a quality assurance program that permits the assignment of its statistically supported limits of uncertainty. The essential features of such a program, consisting of quality control and quality assessment techniques, are discussed in the paper.
The U.S. Environmental Protection Agency's Quality Assurance Program
Authors: Stanley TW , Verner SS
Published: December 2008

The Environmental Protection Agency (EPA) and its predecessor organizations historically have devoted considerable time and effort to the standardization of test procedures, the development and use of calibration and performance audit procedures, quality control and reference samples, training, and other quality assurance (QA) activities. However, these QA activities were essentially voluntary, and most of the data generated were reported with no indication of quality, thereby severely reducing their usefulness. Due to questions concerning the quality of EPA's data, Agency policy stipulated on 30 May and 29 June 1979 requires participation in a centrally managed QA program by all organizational units engaged in environmentally related measurements. This policy applies equally to those extramural efforts performed on behalf of EPA. The primary responsibility for program development and direction is assigned to the Office of Research and Development, while other program offices, regions, and laboratories are responsible for its implementation. Essential elements of the program include developing and implementing QA program plans, QA project plans, and standard operating procedures; conducting audits of the capability and performance of measurement systems, and data quality; maintaining a mechanism for corrective actions; QA training; and frequent reports to management on the quality of data, program effectiveness, and problems. The goal of the QA program is to ensure that all data generated are of known, documented, and acceptable quality.
An Evaluation of Results from Collocated Ambient High-Volume Samplers
Authors: Fritts TW , Hanson MR
Published: December 2008

A data precision assessment of total suspended particulate measurements from collocated samplers on two monitoring programs shows such calculations to be extremely useful both as a quality assurance tool to assess data quality and in the actual analysis of particulate concentration data. Considering the inherent variability in this measurement method, a data precision goal of ± 15% for the 95% upper and lower probability limits is reasonable and attainable. Concentration pairs with percentage differences outside these limits should be carefully scrutinized for possible elimination as outliers before reporting final data precision statistics. Variation in the degree of agreement between data pairs may be attributable to sampler pair configurations, and caused by differential exposure of the samplers to key local particulate sources under various meteorological conditions. The more favorable precision results were attained on the program where high-volume samplers were equipped with covers protecting filters during pre- and post-run idle periods. Operator procedures and diligence also directly affect data comparability.
Certification of Local Laboratories Analyzing Drinking Water in Nonprimacy States
Authors: Hillman JJ
Published: December 2008

This paper discusses the U.S. Environmental Protection Agency (EPA) certification procedures for certifying local laboratories analyzing drinking water for compliance with the Safe Drinking Water Act. A local laboratory is defined as a nonprincipal state laboratory and may include state, county, municipal, federal, or commercial laboratories. The EPA certification program has recently been updated and clarified in the 1983 edition of the EPA certification manual. Critical elements for certification in chemistry, microbiology, and radiochemistry have been revised and include the preparation of a quality assurance (QA) plan. Requirements to maintain certification as well as criteria and procedures for downgrading a laboratory's certification status are described in the manual. Technical services to be provided by EPA have been expanded. The paper briefly describes the certification program, changes that are incorporated in the new manual that will affect the certification of local laboratories, and potential future changes.
Quality Assurance Practices for the Collaborative Testing of Method 6B
Authors: Butler FE , Knoll JE , Rodney Midgett M , Wagner T
Published: December 2008

In 1982, a collaborative test was conducted at a scrubber-equipped, coal-burning power plant to determine the precision, accuracy, and reliability of Method 6B, an Environmental Protection Agency (EPA) test method for analyzing sulfur dioxide and carbon dioxide and for determining the sulfur dioxide emission rate. The quality assurance practices used in the collaborative test are discussed. An important part of the test was preliminary practice runs to allow participants to learn the new procedure. During the test, 24-h samples were collected over a 5-day period by Method 6B, using both continuous and intermittent sampling procedures. In addition, samples were collected for reference data using EPA Methods 6 and 3 and using the plant's continuous emission monitor. The analysis for relative accuracy indicated that the results by Method 6B for both sulfur dioxide and carbon dioxide were within 3% of those obtained by independent methods (i.e., Methods 6 and 3 and the continuous emission monitor). The analysis for precision indicated that repeatability and reproducibility of the sulfur dioxide emission rate were 8 and 11.1%, respectively.
An Industry View of Quality Assurance for Manual Source Sampling
Authors: Brisini VJ
Published: December 2008

Quality assurance programs for manual source sampling methods must provide for valid data while being easily followed and maintained. These programs must be realistic and manageable, while also being cost and manpower effective. It has been the experience of this industry that the most effective method for implementing quality assurance is the establishment of standard procedures which ensure that only proven accepted techniques are utilized for obtaining source samples. These procedures can follow the general guidance of the U.S. Environmental Protection Agency Quality Assurance Handbook, Volume III, but must minimize the paperwork generated by such programs.
Overview of the National Discharge Monitoring Report (DMR) Quality Assurance (QA) Program
Authors: Polvi GR , To YS , Lim EC
Published: December 2008

As mandated by the Clean Water Act, wastewater treatment facilities are regulated under the National Pollutant Discharge Elimination System (NPDES). Direct discharges have unique NPDES permit with discharge limits and a self-monitoring requirement. The effectiveness of the NPDES Program hinges on the quality of the self-monitoring data.

The DMR QA Program evaluates the date quality from the NPDES permittees. Since 1978, the Program has helped to assure the data quality of DMRs. Under this Program, all major permittees are annually sent performance samples, to be analyzed and reported the same way as required in the permits. The results of these permittee tests are compared with an established range of acceptance for each test parameter by EPA to identify potential problems with analytical or reporting procedures. EPA/State then follow-up through correspondence or on-site visits with permittees to resolve the problems.

As an overview, the history, authority, procedures, use of data, and implementation issues are reviewed.
Pulp and Paper Industry Experience with NPDES Quality Assurance Requirements
Authors: Fisher RP
Published: December 2008

Representatives of the pulp and paper industry in the United States have assembled guidelines for preparation for regulatory agency inspections of the framework of quality assurance associated with self-monitoring data collected for National Pollutant Discharge Elimination System (NPDES) discharge monitoring report purposes. These guidelines address effluent flow measurement; sample collection, preservation, and analysis; analysis methods quality control; and record keeping. This paper summarizes the guidelines and presents examples of the experience of the industry with quality assurance-oriented inspections.
Discharge Monitoring Report Quality Assurance Results and Follow-Up by Region VIII U.S. Environmental Protection Agency
Authors: Campbell CL , Hillman JJ
Published: December 2008

The United States Environmental Protection Agency (EPA) is conducting a national quality assurance program known as the Discharge Monitoring Report Quality Assurance Program (DMRQA). Facilities holding permits under the National Pollutant Discharge Elimination System (NPDES) have been sent two sets of audit samples to analyze for permit-required parameters. EPA Region VIII permittees have performed on the average better than other permittees participating nationally in DMRQA Studies One and Two. Follow-up on DMRQA Study One included phone calls, letters, and inspections. Permittee performance in Study Two has improved as a result of Study One follow-up activities. Study Two follow-up will be more extensive than Study One and is currently underway.
Quality Assurance for Human Exposure Studies
Authors: Hackworth LT , Jordan RC , Smith DH , Howard JN
Published: December 2008

Data derived from exposure of human subjects to air pollutants are a basis for setting air quality standards. It is therefore imperative that those data be valid and defensible.

Since 1979, Northrop Services, Inc.-Environmental Sciences, under contract to the U.S. Environmental Protection Agency, has been responsible for the development and implementation of a comprehensive program of quality assurance for human exposure studies. Exposure studies are conducted in controlled environment laboratories located in Chapel Hill, North Carolina.

The planning and design of the quality assurance (QA) program are discussed. Details of the conduct and scheduling of systems and performance auditing, as well as hardware and software needs, are provided. A historical review of auditing results is presented, and unique problems are described for pollutant generation, delivery, and control systems as well as environmental control and physiological data acquisition.
Reference Samples for Water-Related Programs in the U.S. Environmental Protection Agency
Authors: Winter JA
Published: December 2008

The Environmental Monitoring and Support Laboratory at Cincinnati provides quality assurance (QA) support for U.S. Environmental Protection Agency (EPA) water-related programs in response to the Clean Water Act (P.L. 92-500), the Safe Drinking Water Act (P.L. 93-523), the Marine Protection, Research, and Sanctuaries Act (P.L. 92-532), the Resources Conservation and Recovery Act (P.L. 94-580), the Comprehensive Environmental Response and Liability Act (P.L. 96-510), and the Toxic Substance Control Act (P.L. 94-469), and their amendments.

Two important segments of this support are the Quality Control Sample Program, which furnishes samples of known concentrations for use as independent checks on intralaboratory QA activities, and the EPA's Repository for Toxic and Hazardous Materials, which provides calibration standards and spiking solutions for trace organic analyses of interest to the Agency. Each series contains one or more analytes, with true or reference values. The samples and standards are prepared as stable concentrated solutions in all-glass ampuls for dilution to volume, and analyses by EPA, its contractors and grantees, and other federal, state, and local agencies.
Placement of Asphalt Concrete Mixtures
Authors: Scherocman JA , Martenson ED
Published: December 2008

A brief description of the history of the development of the asphalt paver is given in this paper. It discusses the principle of the floating screed and the operation of the paver tractor unit and screed unit. The forces that act on the screed and keep it in balance (level) to provide a smooth asphalt concrete mat are explained. Improvements in paver design and operation are detailed, and the most recent innovation of the self-widening screed is described. It is pointed out, however, that the basic operational functions of a modern paver are still the same as developed over 50 years ago. The paper also describes the causes of and cures for twelve different common problems that can occur in the asphalt concrete mat behind the paver. Emphasis is placed on why the various deficiencies have occurred and on what can be done to correct the problem when it does happen. Finally, for each mat problem area, the paper discusses the affect of each defect on the long-term performance of the asphalt concrete pavement structure.
Development of a Fatigue Crack Propagation Model of Incology 901
Authors: Schwartz BJ , Engsberg NG , Wilson DA
Published: December 2008

An interpolative crack propagation model was developed for Incology 901 using a hyperbolic sine function. The equation log(da/dN) = C1 sinh[C2(logΔK) + C3)] + C4 is used to describe crack growth rates at various operating conditions. Crack propagation rate data for varying stress ratios were examined over a broad range of temperatures and frequencies with this model. Stress ratios (R) investigated included both positive and negative values ranging from −1.0 to a maximum of 0.7. The influence of increasing temperature on crack growth was examined over a temperature range of 260 to 620°C (500 to 1150°F). Frequencies from 0.00833 to 30 Hz were investigated to simulate conditions experienced by a gas turbine engine disk of this material. The resulting model can be used as an effective tool to predict residual life of a gas turbine engine disk, because growth rates can be obtained even where data are unavailable.
Effect of Section Size on Transition Temperature Behavior of Structural Steels
Authors: Landes JD , McCabe DE
Published: December 2008

The transition temperature behavior of structural steels was evaluated using fracture mechanics specimens and elastic-plastic evaluation techniques. In the transition temperature region, the ductile tear and JR-curve behavior of structural steels was relatively independent of test temperature and specimen geometry effects. Consistent JR-curve development was interrupted by Jc instability events, however, and it is this property that showed high sensitivity to test temperature and constraint variations. The temperature at which the Jc instability toughness rises rapidly was dominated by specimen thickness but within this behavior was a subtle interaction with constraint variations due to ligament length variations.

Specimens of fixed proportionalities can be used with Weibull analysis and extremal statistics methodology to demonstrate why the transition temperature behavior of steels is specimen size dependent. A distribution of Jc cleavage instabilities on small specimens can be used to predict Jc instability distributions on larger specimens.
Microcrack Initiation and Growth in a Pearlitic Steel—Experiments and Analysis
Authors: Leis BN
Published: December 2008

Results of experiments indicate that crack growth from a notch root in a 1080 pearlitic (rail) steel exhibits anomalous behavior when analyzed in terms of linear elastic fracture mechanics (LEFM). (Cracks as long as 0.4 cm exhibit anomalous behavior.) It is shown that the length of crack exhibiting anomalous behavior corresponds with the size of the plastic zone at the notch root. A model is presented which characterizes the crack growth driving force in terms of the displacement (strain) control condition that this inelastic notch field is postulated to impose on cracks contained within it. It is shown that the model reasonably predicts the growth rate behavior within the inelastic notch field. Notched component life predictions, based on this model, coupled with a nonlinear scheme to predict the formation of a 125 μm crack and LEFM analyses to continue growth beyond the inelastic field, are presented. It is shown that, for the pearlitic steel examined, the life of the components is equally divided between initiation and growth within the inelastic notch field at higher stresses. As the applied cyclic stress applied decreases, initiation becomes increasingly dominant. The portion of life controlled by LEFM behavior is negligible except within a narrow window of cyclic stress. The implications of this observation are discussed with respect to other materials and notch severities.
Fracture Toughness of High Strength Steel Predicted from Charpy Energy or Reduction in Area
Authors: Underwood JH , Leger GS
Published: December 2008

Analysis is presented of the results of an extensive mechanical and fracture test program. Ninety-six hollow cylinder forgings of A723 steel with five different manufacturing processes were tested at two locations with different outer diameters. Yield strength, plane-strain fracture toughness, Charpy impact energy, and tensile reduction in area were measured and analyzed for statistical variation and difference of mean value. Linear regression was used to fit lines to the data and to determine correlation coefficients. Conclusions were drawn as to the suitability of Charpy energy and reduction in area as predictors of plane-strain fracture toughness.
Single-Specimen J-Resistance Curve Evaluations Using the Direct-Current Electric Potential Method and a Computerized Data Acquisition System
Authors: Wilkowski GM , Wambaugh JO , Prabhat K
Published: December 2008

This paper describes the direct-current electric potential method of monitoring crack initiation and stable ductile crack growth. In many aspects this method is simpler than the unloading compliance method, and it can be readily incorporated into a computerized data acquistion system. Numerous examples using this technique and a computerized data acquisition system are given for bend and compact specimens, different loading rates, and different materials (Type 304 stainless steel, Zircaloy, and carbon steels).
Application of a Tearing Instability Analysis for Strain-Hardening Materials to a Circumferentially Cracked Pipe in Bending
Authors: Pan J , Ahmad J , Kanninen MF , Popelar CH
Published: December 2008

All previous tearing instability analyses for circumferentially cracked pipes require the use of a limit-load assumption. In this paper a more general approach is developed for power law hardening materials. Specifically, a simple J and (∂J/∂a)ΔT estimation scheme for a circumferentially cracked pipe subjected to four-point bending is developed using a power hardening law for the plastic part of deformation. The predictions of crack initiation and tearing instability are compared with experimental data. Comparisons with tearing instability predictions using the limit-load approach are also provided.
The Purity Determination of Three Compendial Steroids by Differential Scanning Calorimetry
Authors: Lim OB , Oliver EA
Published: December 2008

The use of a differential scanning calorimetry (DSC) with a data reduction system and a commercially available purity program is presented as an alternate method for the determination of the purity of the steroids Norethindrone, Mestranol, and Ethinyl Estradiol currently listed in the United States Pharmacopeia (USP). This method's ability to determine the purity of a material without recourse to the use of a pure reference standard of the same substance has been seen as one of the major advantages of differential scanning calorimetry (DSC).

An evaluation of the applicability of the DSC methodology was carried out using prepared steroid mixtures. Compositions of 1 and 4% of foreign related steroids with each chosen steroid were used to establish predetermined purity levels for subsequent analysis. As the primary objective of this work was to establish an alternate method for the purity evaluation of pharmaceutical grade raw materials, comparison with the current USP and equivalent methodology was carried out. Thus, results also were obtained for both ultraviolet spectrophotometric (USP) and gas chromatographic methods. Good correlation was obtained between the three methods. However, the DSC method proved to have superior characteristics in terms of precision and accuracy and hence offers an attractive and reliable alternative for the determination of the purity of these materials.
Introduction to Damage Tolerance Analysis Methodology
Authors: Grandt AF
Published: December 2008

The objective of this paper is to introduce analysis methods for evaluating the impact of preexistent cracks on structural performance. Linear elastic fracture-mechanics concepts are briefly described and used to compute the critical crack size for a given component and loading (specify fracture conditions) and to determine the time required for a smaller, subcritical crack to grow to critical size by fatigue or stress corrosion cracking or both. Limitations of linear elastic fracture mechanics are discussed in order to define problems that can be confidently analyzed by the method and to identify areas that require more sophisticated approaches. A particular goal is to establish the background for more specialized topics considered by other papers in the present volume.
Liquid Rocket Injector Atomization Research
Authors: Ferrenberg AJ
Published: December 2008

This paper describes the need for, application of, and state of the art of rocket engine atomization studies and droplet size measurement techniques that have been applied to liquid rocket engine propellant injectors. In addition, the capabilities of droplet sizing techniques required or desired or both for such atomization studies are discussed. Finally, the results of tests to evaluate droplet sizing interferometry employing the visibility technique and a technique involving both visibility and intensity are discussed.
Tungsten: Its Manufacture, Properties, and Application
Authors: Mullendore JA
Published: December 2008

A brief review is given of the manufacture of tungsten from ore to finish product. Some of the important properties are discussed, and a comparison is made of the properties of tungsten and those of other metals. The uses of tungsten are given as they relate to its properties.
Process and Device Modeling for VLSI Structures
Authors: Plummer JD
Published: December 2008

Accurate and efficient simulation of VLSI processes and device electrical characteristics can complement and in some cases eliminate costly experimental evaluation of proposed new structures. Such techniques are also potentially very useful in optimizing existing processes. The utility of process and device simulators like SUPREM, GEMINI and others depends, however, on the accuracy of their predictions. This accuracy is fundamentally linked to the physical models employed by such computer tools. This paper assesses the present status and capabilities of such programs and demonstrates by way of examples both what they can and cannot presently do. Future improvements in such simulators must come from improved physical models, especially if such tools are to be successful in predicting structural and electrical characteristics of micron and submicron size devices. Future trends and problem areas are also surveyed.
The Annealing and Low Temperature Aging Characteristics of Fine Diameter Wire Produced from Dilute Aluminum Alloys
Authors: Hebert DF
Published: December 2008

Compared are the ultrasonic bonding, annealing and low temperature aging characteristics of one mil Al-1 pct Si, Al-1 pct Mg, and Al-½ pct Mg bonding wires. Ultimate tensile strengths and average bond pull strengths of these three alloys decrease similarly in the 125° to 200°C temperature range, while dissimilarity was observed in elongation: Al-Mg alloys become more ductile and Al-1 pct Si embrittles. Aging to −65°C showed no changes in the mechanical properties of Al-½ pct Mg but caused embrittlement in Al-1 pct Mg, suggesting GP zone formation.
A Comparative Study of the Mechanical Properties of Bonding Wire
Authors: Hannula S-P , Wanagel J , Li C-Y
Published: December 2008

This study was undertaken to investigate the mechanical behavior of bonding wires. Beryllium doped gold and aluminum 1-percent silicon wires from three different manufacturers were tested to determine the elastic, tensile and load relaxation properties. The stiffness (modulus) of the wires was found to depend on the method of fabrication as well as on thermal and mechanical history. Although the specified breaking load and elongation values of the wires were essentially the same, load relaxation tests revealed substantial differences in the time dependent flow properties of the wires. Low temperature annealing, which was performed to simulate prolonged storage of the wires, resulted in changes in the properties of both the gold and the aluminum 1-percent silicon wires.
Production and Development of Neutron Transmutation Doped Silicon
Authors: Herzer H
Published: December 2008

Considering the production of NTD-silicon our interest is focussing on market growth, application fields and questions like reactor capacity, costs and material quality. Market growth still is in a further steady increase and since IC application particularly CMOS devices are not expected to turn over to NTD-silicon there is plenty of reactor capacity available to follow the market increase in power device application.

Further development of NTD-silicon is discussed regarding maximum diameter, upper resistivity limit and quality aspects.
Effects of Hydrogen on Defects in Neutron Irradiated Silicon
Authors: Du YC , Zhang YF , Meng XT
Published: December 2008

Effects of hydrogen on electrical properties and annealing behavior of radiation defects in N- and P-type Si (H) irradiated by neutron have been studied by DLTS, IR absorption, resistivity and minority carrier lifetime measurements. In as-grown and neutron irradiated Si (H), some Si -H IR bands and hydrogen-related deep centers have been observed. Because of hydrogen in silicon, the production rates of radiation defects decreased, and the passivation action of hydrogen emerged unambiguously at 200°c annealing temperature or higher. These cause the differences of annealing behavior of the resistivity and lifetime between Si(H) and Si(Ar).
Potential for Large-Diameter NTD Silicon Production in the Advanced Test Reactor
Authors: Herring JS , Korenke RE
Published: December 2008

The Advanced Test Reactor (ATR) is a 250-MWth flux-trap reactor located at the Idaho National Engineering Laboratory (INEL). Within the reflector are four 124-mm-diameter I-holes, which are available for silicon irradiation. Two large irradiation volumes of 0.5 m × 0.4 m × 1.2 m and 0.5 m × 0.2 m × 1.2 m are also available for transmutation doping. Thermal fluxes in these locations range from 0.56 to 23.0 × 1012 nt/cm3-s. Use of the ATR for providing neutron transmutation doping (NTD) services in sizes not available elsewhere in the United States may be feasible.
Chevron-Notch Bend Testing in Glass: Some Experimental Problems
Authors: Chuck L , Fuller ER , Freiman SW
Published: December 2008

This study describes experimental difficulties in the use of the chevron-notch bend test to determine the plane-strain fracture toughness, KIc, for brittle materials. Four-point flexure tests were performed on soda-lime-silica glass and vitreous silica in both “wet” and “dry” environments and at various loading rates. Results show that an inability to produce stable crack growth in the chevron-notch bend test can lead to serious overestimates of KIc as well as to significant scatter in the data. It is also shown that water enhanced crack growth can reduce the measured value of KIc.
Investigation of Acoustic Emission During Fracture Toughness Testing of Chevron-Notched Specimens
Authors: Stokes JL , Hayes GA
Published: December 2008

Acoustic emission (AE) monitoring in conjunction with fracture toughness testing of chevron-notched specimens was employed to investigate crack growth in four steels prepared by electroslag-remelt casting. 15-5PH, AISI 4140, D6AC, and AISI 440C were investigated. AE data were recorded and correlated with variations in fracture toughness test behavior and fracture surface topography. AE parameters such as total counts, count rate, amplitude distribution, etc., were used to characterize flow and fracture processes. AE measurements were observed to have good correlation with crack growth parameters and the energetics of discrete cracking events.
Effect of Low Temperature on Apparent Fatigue Threshold Stress Intensity Factors
Authors: Esaklul KA , Yu W , Gerberich WW
Published: December 2008

Near-threshold fatigue crack growth in high-strength low-alloy (HSLA) steel, Fe, and Fe-Si alloys was found to depend on test temperature from room temperature down to 123 K. Near-threshold crack growth rates were lowered and threshold stress intensity factors increased with decreasing temperature. A “prominent” closure was observed for all test temperatures and materials and was further confirmed by the examination of fracture surfaces. The magnitude of closure increased with decreasing temperature, suggesting a dependence on yield strength and fracture morphology. The effects of R ratio were found to be closure-related for the same fracture processes. However, a change in the fracture process, (e.g., to cyclic cleavage) may lead to a ΔKth(eff) dependence on load ratio even at very high R values. Hence mean stress may affect threshold independently of any closure-related phenomena. A reasonable correlation was obtained with a theoretical model for closure that could account for both geometrical and reversed plasticity phenomena.
Metal Ion Sensors Based on Immobilized Fluorogenic Ligands
Authors: Seitz WR , Saari LA , Zhujun Z , Pokornicki S , Hudson RD , Sieber SC , Ditzler MA
Published: December 2008

A metal ion sensor may be prepared by immobilizing a fluorogenic ligand on the common end of a bifurcated fiber optic. Fluorescence is excited through one arm of the fiber optic and observed through the other. When the immobilized ligand is placed in a solution of metal ion, some of the metal associates with the ligand causing its fluorescence characteristics to change. Equations are derived for the response of a sensor for systems where a 1:1 complex is formed.

We have successfully immobilized several ligands including morin, quercetin, and calcein to cellulose using cyanuric chloride as a coupling reagent. Immobilized morin is only very weakly fluorescent but forms fluorescent complexes with Al+3 and Be+2 and can be used to sense these ions. Immobilized calcein is fluorescent by itself but is quenched by several metal ions. We have also immobilized hydroxy napthol blue and 8-hydroxyquinoline-5-sulfonate on anion exchangers. In addition 2, 2′, 4-trihydroxy-azobenzene and p-tosyl-8-aminoquinoline have been immobilized to silica gel.