bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Relationship Between Water Demand and Particle Size Distribution of Stucco
Authors: Luckevich LM , Kuntze RA 
Published: December 2008

In gypsum board production, the amount of water required for a stucco slurry with a suitable fluidity is considerably greater than the amount necessary for hydration of the stucco. Since excess water must be removed by drying, it is advantageous, from an energy point of view, to reduce the consistency or water demand of stucco. Constant board density is maintained thereby through increased addition of foam.
The high water demand of stucco produced by conventional calcination methods is due largely to the ability of the stucco to disintegrate, a process during which larger stucco particles break down into smaller particles upon contact and subsequent mixing with water. The water demand of stucco may be reduced by aging, that is, the exposure of stucco to water vapor over a period of time, which reduces the ability of the stucco to disintegrate. However, aging also has a negative effect on both setting characteristics of the stucco and, as a result, on the strength of the gypsum formed.
The objective of the work described in this paper was to study the relationships between water demand and particle size distribution as affected by changes in disintegration during aging. Particle size analysis and several methods of consistency measurement were used for this purpose. It was found that a direct relationship exists between water demand of stucco and particle size distribution as defined by percent disintegration, with minor deviations at initial stages of aging. In contrast, nonlinear relationships were found, with preliminary experiments, for stuccos containing aridizing agents or surfactants, which indicates that the water demand of stucco is also affected by surface properties. The water demand of stucco is not a function of the surface area of the stucco, that is, other properties, such as particle shape and surface characteristics, play a significant role. Similarly, the magnitude of the differences in water demand of various types of stucco indicates that particle size distribution, although the major factor, is not the only one influencing this property.
Quality Assurance Aspects of Environmental (Aerometric) Data Management
Authors: Beebe RC , McDaniel AS , Clement DW 
Published: December 2008

Considerable attention has been directed towards techniques and procedures which facilitate the high quality of field-collected ambient environmental data.
This study addresses the quality control methods used to assure data quality after the data have been recorded. The two major elements associated with the validation of much of Tennessee Valley Authority's (TVA's) environmental data are: (1) initial computer flagging of physically/chemically questionable and outlying data and (2) analyst review and feedback to field technicians to implement corrective actions. Examples of these procedures as applied to aerometric data will be discussed.
The benefits of this approach include timely feedback to the field technicians to resolve potential problems with a monitoring system and assignment of quality code ratings and precision and accuracy to all archived and reported data.
Steps to Valid Particle Size Data from Emissions Sources
Authors: McCain JD , Felix LG , Farthing WE 
Published: December 2008

This presentation is directed toward applications of those devices most commonly applied in the measurement of industrial source particle size distributions: cascade impactors and cyclones. Quality assurance (QA) in field programs set up for the determination of particle size distributions includes many of the same steps as those for the determination of particulate concentration and emission rates such as would be applicable to Environmental Protection Agency (EPA) Methods 5 and 17. However, a number of additional levels of QA must be added. These include specifying and verifying protocols for withdrawing a representative sample from the gas stream, steps to minimize and correct for the effects of interferences, operating protocols to ensure that the sampling conditions fall within the constraints of the hardware being used, sampler preparation, sample handling, and record-keeping.
Examples of specific problem areas to be addressed are (1) traverse methodology; (2) the number of samples required to obtain a given confidence level in the results; (3) the selection of samplers and the choice of operational parameters such as sampling flow rate; (4) inteferences, controls, and blanks; (5) sample recovery and handling; and (6) post-test verification that the actual sampler operation fell within the limits for reliable performance for the device(s) used.
Development of Statistics and Limits for DMR-QA Studies, and Summary of Experience in DMR-QA Study 2
Authors: Britton PW 
Published: December 2008

The U.S. Environmental Protection Agency (EPA) has conducted two Discharge Monitoring Report — Quality Assurance (DMR-QA) studies to evaluate the performance of laboratories doing analyses required in major National Pollution Discharge Elimination System (NPDES) permits. The object of these studies is to identify laboratories that appear to be having significant analytical problems and that should receive follow-up contact by the state or EPA region with primacy.
Participants receive a set of sample concentrates to be diluted to volume with distilled water. The resulting samples can be analyzed for 26 of the analytes most frequently limited in permits. Analytical results are submitted to EPA for evaluation against appropriate acceptance limits and a report is returned to each participant. The acceptance limits are constructed as 99% confidence intervals based upon the state-of-the-art analytical capabilities demonstrated by participating EPA and state laboratories. The statistical basis for the acceptance limits in the most recent study, DMR-QA Study 2, is discussed in detail.
DMR-QA Study 2 included data representing 5157 major NPDES permits and all 50 states. On the average, 22% of these data were beyond the acceptance limits, indicating there is considerable potential for improvement. Results from DMR-QA studies focus the limited follow-up resources of the primacy agencies to maximize the improvement in DMR data quality. Whether any improvement actually occurs, however, depends entirely upon the commitment of the responsible state and EPA enforcement offices, as well as the major NPDES dischargers, to make the changes necessary to improve the quality of monitoring data.
Quality Assurance of Meteorological Measurements
Authors: Lockhart TJ 
Published: December 2008

The quality assurance (QA) program for meteorological measurements must begin with a QA plan which identifies the purposes for which the measurements will be made. Assume a monitoring task where a one-year data set of hourly values of wind speed, wind direction, air temperature, relative humidity, and precipitation amount is needed to describe the air quality measurements being automatically recorded.
The QA plan will define the accuracy needed for this description and will give the quality control tasks necessary to produce data of this accuracy. The plan will also address the auditing tasks necessary to assure that the data, in their final use form, meet these requirements.
Each variable must be addressed in terms of measurement method or instrument type, sensor siting, data handling (especially averaging or editing), and representativeness. The question of representativeness has many facets. First, one must be sure that the measurement itself has no bias or that the bias is understood. Given an unbiased measurement at the sensor location, one must be sure that location is what the use requires. Finally, the hourly value used should represent the time period the use requires. For example, if a back-trajectory analysis is needed to estimate the volume location from which the air quality instrument was sampling, the hourly wind data should be a vector average for the hour and not an instantaneous or few-minute average taken once an hour.
Quality Assurance Considerations in Conducting the Ames Test
Authors: Williams LR 
Published: December 2008

This paper provides general and specific guidance for the development and implementation of a quality assurance program for Ames testing. An effective quality assurance program is needed to assure that data produced from short-term mutagenicity testing (e.g., the Ames test) are of known quality and comparable among laboratories conducting the testing. The success of such a program begins with a personal and organizational commitment to data quality. Next, standardized procedures for the conduct and control of the testing process should be adopted and rigidly followed. Finally, participation in an external quality assurance program is necessary for independent confirmation of testing performance and confirmation of interlaboratory data comparability. Comparability of test data is required if there is to be confidence in the results of testing activities and acceptance of the resulting interpretation of test findings.
Detailed quality control procedures are outlined for the Ames test. These include procedures for confirming the genotype and responsiveness of tester strains, confirming the absence of bacterial contamination, providing appropriate positive and negative test controls, confirming the enzymatic activity of metabolic activators, and determining the adequacy of test data.
The functions and responsibilities of an effective quality assurance program are outlined. Primary functions include development of standards based upon technically attainable criteria, assistance to participating laboratories in adopting those standards, and independent evaluation of the success of the laboratories in meeting those standards.
The Use of Natural Waters as U.S. Geological Survey Reference Samples
Authors: Janzer VJ 
Published: December 2008

The U.S. Geological Survey conducts research and collects hydrologic data relating to the Nation's water resources. Two water quality laboratories in Atlanta, Georgia, and Denver, Colorado, support the national research programs, and provide chemical analyses of natural waters for the data program. Additional chemical water quality data are provided by cooperator and contract laboratories.
Continuous quality assurance efforts with these laboratories require several thousand reference samples each year. Reference samples approximating actual field samples provide the most realistic quality assurance for the laboratories. Seven types of natural matrix reference water samples are prepared for use in the Survey's quality assurance program. These include samples containing major constituents, trace metals, nutrients, herbicides, insecticides, trace metals in a water and suspended-sediment mixture, and precipitation (snowmelt). To prepare these reference samples, natural water is collected in plastic drums and the sediment is allowed to settle. The water is then filtered, selected constituents are added, and if necessary the water is acidified and sterilized by ultraviolet irradiation before bottling in plastic or glass. More than 1000 1-L samples of a given type may be prepared at a time. These reference samples are distributed twice yearly to more than 100 laboratories for chemical analysis. The most probable values for each constituent are determined by evaluating the data submitted by the laboratories using statistical techniques recommended by ASTM.
A stockpile of several thousand reference samples is maintained by the preparation of new samples as needed. Periodically, some of these samples are submitted to laboratories as “unknowns”. When the analytical data for these samples are reported and evaluated, problem areas detected are promptly reported to the respective laboratory.
Use of both identified and unidentified reference samples provides some of the quality assurance data necessary to ensure the continuing accuracy of chemical analyses obtained to support the Survey's basic water-data collection and research program activities.
Sampling of Copper Cathodes
Authors: Lamela M , Palacios C 
Published: December 2008

In order to devise a system for the sampling of copper cathodes using a mechanical punch it was first necessary to establish the distribution of impurities between individual samples and their location. To do this a cathode was divided into 171 pieces and each piece melted individually. Samples for analysis were then taken from the melt by suction through a 3.8-mm-ID glass tube and analyzed for impurities by emission spectrometry. The results obtained were summarized and studied statistically to determine the average content and standard deviation.
It was then essential to correlate this information with the results obtained when sampling plant production using a mechanical punch. For this purpose a total of 578 cathodes (60 tonnes) was sampled, a template was used to locate 30 sampling points across the diagonal of a cathode, and 5 buttons were taken from each cathode in such a way that all 30 sampling points were punched an equal number of times. The 5 buttons from each cathode were melted, sampled and analyzed in a similar manner to that used for the sampling of the individual cathode. These results were also studied statistically, and in combination with the first results an overall standard deviation was determined statistically under various combinations of number of cathodes selected, number of buttons from each sample cathode, and number of samples per final sample.
From this work it has been determined that, at this particular plant, it is satisfactory when sampling a lot of approximately 60 tonnes to punch 5 buttons from each of 6 selected cathodes, to melt the 30 samples together, and to figure an arithmetic average of 3 analyses of the sample taken from the resultant melt.
A Failure Assessment Approach for Handling Combined Thermomechanical Loading
Authors: Bloom JM , Malik SN 
Published: December 2008

This paper presents a failure assessment approach for the handling of combined thermomechanical loading of nuclear pressure vessels. The proposed approach is based on a failure assessment curve that accounts for the thermal and mechanical stresses in terms of the elastic stress intensity factor with a plastically corrected crack length. The square of this stress intensity factor divided by the effective elastic modulus is added to a J-integral deformation plasticity solution term. The result is valid for the full range of material/structural behavior, from linear elastic to fully plastic. The fracture behavior parameter, the total J-integral, can then be formulated in terms of a failure assessment curve to account for the combined loading states.
The proposed approach was benchmarked using a modified Babcock & Wilcox version of the ADINA computer program. The program generated incremental plasticity finite element crack solutions for a single edge cracked plate and a circumferentially flawed cylinder subjected to thermomechanical loadings. The ADINA finite element results agreed quite well with the proposed failure assessment approach.
The failure assessment approach is illustrated by a sample problem of a postulated accident condition, based on the occurrence of an overcooling transient (thermal loading) combined with an uncontrolled repressurization (mechanical loading) of a typical nuclear reactor vessel.
Temperature Dependence of Fracture Toughness of Large Steam Turbine Forgings Produced by Advanced Steel Melting Processes
Authors: Swaminathan VP , Landes JD 
Published: December 2008

Three advanced steel melting processes—low sulfur vacuum silicon deoxidation, electroslag remelting, and vacuum carbon deoxidation—were applied to produce three Cr-Mo-V ASTM A470, Class 8 steel forgings for steam turbine application. Plane strain fracture toughness (KIc) values were obtained using 2T and 3T compact specimens between 24 and 93°C (75 and 200°F). The elastic-plastic fracture toughness (JIc) was obtained using 1T-CT and round compact specimens at 149, 260, and 427°C (300, 500, and 800°F). Both multiple specimen “heat-tint” techniques and single specimen “unloading compliance” techniques were employed at 149°C (300°F) to generate J-R curves. Both of these techniques yielded results with excellent agreement. Round CT specimen results agree well with standard CT specimen results.
These advanced technology forgings show significant improvement (factors of two to three higher) in fracture toughness over conventionally produced forgings. This increase in toughness is attributed mainly to the ability of these processes in producing cleaner steel, especially with very low sulfur content, and the associated reduction in the amount of nonmetallic inclusions. Minimums in toughness and the tearing modulus at 260°C (500°F) were observed. These minimums correspond to the occurrence of minimum in the tensile ductility at the same temperature which may be due to the dynamic strain-aging phenomenon.
Fracture Toughness of Stainless Steel Weldments at Elevated Temperatures
Authors: Garwood SJ 
Published: December 2008

This paper comprises a study of the resistance to the propagation of a ductile tear in 316 stainless steel parent plate in all six orientations, and submerged-arc and manual metal arc weld metal and heat-affected zone (HAZ) regions in stainless weldments at 370 and 540°C. Tests were carried out in bending and tension in both load and displacement control at 370°C. The propagation resistances of the various regions are assessed from the measurement of resistance curves and maximum load toughness using both crack tip opening displacement (CTOD) and J-integral parameters.
The T-L orientation appears to have the poorest resistance to tearing of the four normal cracking orientations for parent plate. The S-L orientation, however, has the worst toughness overall. Heat-affected zone toughness of both manual and submerged-arc welds is equivalent to parent plate. Submerged-arc weld metal toughness is comparable with the T-L orientation in plate material. Manual metal arc weld metal toughness is inferior to the toughness exhibited by submerged-arc and the four normal cracking orientations in parent plate. Increasing the test temperature from 370 to 540°C for manual metal arc weld metal appears to produce a distinct increase in resistance to ductile crack propagation.
Provided adequate thickness constraint is ensured, maximum load toughness determinations from the standard laboratory three-point bend geometry would appear to give conservative estimates of tensile instabilities under load control. The relevance of this behavior is discussed in terms of the use of single-parameter design curve methods for the estimate of tolerable flaw sizes in structural applications
Crack Growth Resistance Measurement by Crack Opening Displacement Methods
Authors: McCabe DE , Ernst HA 
Published: December 2008

In a previous investigation, tests had been conducted on compact specimens made of A508 Class 2A steel to study specimen geometry effects on JR-Curve behavior. No particular geometry effects were shown in specimens ranging in size from ½T to 10T when conditions for J-controlled growth were satisfied. These same specimens had been instrumented to develop crack opening displacement (COD) toughness values using a plastic hinge model. The COD-type R-Curve behavior was examined herein for specimen geometry effects and crack opening angle (COA) behavior.
Plastic hinge (the position of a center of plastic rotation), COD, and COA were determined using a frame-type fixture that had been originally introduced by Andrew. The smallest specimen included herein was 1T and the largest was 10T. COD inferred from the plastic hinge model was determined at the original crack tip position (δ0) and at the advancing crack tip position (δt).
Experimental COD and COA data and some theoretical evaluation schemes indicated that there is geometry-dependent δt versus Δap type R-Curve behavior. It was therefore concluded that JR and experimentally measured COD are incompatible with respect to geometry independence of R-Curve behavior. It was shown that the plastic hinge ratio is strongly influenced by ligament dimensions and that this hinge ratio ultimately controls the δt and δ0 values of COD once the plastic displacement becomes significant with respect to total displacement.
An Overview of the Calorimetric Purity Measurement
Authors: Brennan WP , DiVito MP , Fyans RL , Gray AP 
Published: December 2008

The well-known effect of impurities on the melting behavior of crystalline compounds provides the basis for the determination of the purity of these compounds by differential scanning calorimetry (DSC). In the Perkin-Elmer DSC method for the determination of the purity of crystalline compounds, the van't Hoff equation is used to describe the rate of melting of a compound as a function of sample temperature. The presence of an impurity will broaden the melting peak of the compound and lower the final melting point from To, the melting point of a 100% pure compound, to Tm, the melting point of the impure mixture. If careful sample preparation and slow scanning rates are employed to approach thermodynamic equilibrium, accurate estimation of the true purity of a compound can be determined.
The recommended DSC procedure involves the use of a relatively small sample size consistent with homogeneity, the tightest possible encapsulation to minimize temperature gradients within the sample, and the slowest possible scanning rate to approach equilibrium conditions. Also, it is recommended that the melting curve be analyzed over a range of fraction melted (usually 10 to 50%), where the curve is least sensitive to possible gradients in the instrument-sample system.
Preparation and Evaluation of a Set of Thermal Purity Standards
Authors: Moros SA 
Published: December 2008

Determining the attributes of any analytical method or comparing methods is best carried out using an actual sample of known composition. When this is lacking, a standard reference material, that is, an appropriate material of reliably known composition which is generally available, may be substituted.
An ASTM Committee E-37 task force recognized the need for a set of thermal purity standard reference materials, chose the phenacetin-aminobenzoic acid system, and, in a collaborative study, showed the viability of a set of standards over the 100 to 98.5 mol % purity range. As an outgrowth of this, quantities of materials sufficient for distribution by the National Bureau of Standards (NBS) and covering a wider impurity range, were prepared. The mixtures were then assayed by independent analysts employing different methods and at various times. Concordant results proved the composition and showed each mixture to be stable and homogeneous.
The NBS is now in the process of evaluating the set of mixtures for designation as Standard Reference Materials.