bluuebunny/crossref_metadata_2025_split huggingface dataset:
Byproduct Gypsum
Authors: Pressler JW 
Published: December 2008

The United States was the world's leading consumer of crude gypsum in 1982, with a demand of 16 million metric tons in the manufacturing of gypsum wallboard as a set retarder in cement, and some demand for its uses in agriculture. Only about 4% of this was byproduct gypsum sold for agricultural land plaster. Byproduct gypsum is the chemical end product of industrial processing plants, consisting primarily of calcium sulfate dihydrate, CaSO4·2H2O. The oldest byproduct-gypsum-producing industry is that of the phosphate rock chemical processing in Florida. Large sludge ponds and retaining stockpiles are accumulating, and total tonnage may approach 1 billion metric tons by year 2000. The United States has no firm plans for recycling and utilization of this and other forms of byproduct gypsum. Environmental pressures because of solid pollution and the increasing cost of land may influence the United States to develop better utilization within the next ten years. Projected production of byproduct gypsum from coal burning power plant fluegas desulfurization systems may be equal to the production tonnage of 30 million metric tons per year of phosphogypsum by 1990, thus adding more social and economic pressures for utilization.
Japan phased out natural gypsum production in 1976, and now is recycling 6 million metric tons per year of byproduct gypsum for wallboard, cement, and plaster. She is now leading the world in the technology of utilization of byproduct gypsum, with a balance established between supply and demand. European countries have active research and development projects but are still dumping many million tons per year into the sea.
It is suggested that the United States use more of the increasing tonnages of byproduct gypsum for its traditional uses of wallboard, plaster, and as a set retarder in cement. Other high-tonnage uses are offered, such as cellular foamed gypsum for insulation, road construction, gateway supports in coal mines, and its potential as the largest sulfur resource in the world.
Quality Assurance Project Plans—A Key to Effective Cooperative Monitoring Programs
Authors: Brossman MW , Hoogheem TJ , Splinter RC 
Published: December 2008

The use of cooperative monitoring programs, involving the co-mingling of data of the regulated community and the “regulators,” can lead to effective utilization of resources and contribute to cooperative solutions to our pollution control programs. Such benefits can only be realized, however, under controls which ensure the comparability and validity of data obtained through well-defined roles and work plans. A key to this control is the Work/Quality Assurance (QA) Project Plan developed cooperatively by the type of team reflected in the authorship of this paper, namely by federal, industry, and state/municipal representatives.
A comprehensive Work/Quality Assurance Project/Work Plan Guidance document has been developed in the Office of Water, U.S. Environmental Protection Agency (EPA), which should effectively meet QA requirements for a wide range of users and types of water-monitoring tasks. This guidance document is designed to cover all aspects of water environmental measurement from field sampling through laboratory analysis and data reduction and, where applicable, computer input.
The document integrates a work plan with a QA plan eliminating the dual effort of overlapping plan developments and assuring practical incorporation of quality assurance/quality control. In addition, the combination of the work plan and QA plan provides a comprehensive basis to establish sound coordination and agreement for cooperative monitoring tasks. This guidance document is currently in pilot implementation throughout the United States.
An Analytical Method and Quality Control Program for Studies of Currently Used Pesticides in Surface Waters
Authors: Kramer JW , Baker DB 
Published: December 2008

Studies of the transport and loading of currently used pesticides in rivers draining large agricultural river basins pose numerous problems for the analytical laboratory. Most of the annual export occurs during the first two runoff events following the period of major pesticide application. Rapidly changing pesticide concentrations during these events require the use of automatic samplers for collections over the hydrograph. Each sample must be scanned for a wide variety of pesticides and samples frequently contain high concentrations of suspended sediments.
We have developed an analytical procedure which focuses on those pesticides which can be directly extracted in methylene chloride and analyzed by capillary gas chromatography. The procedure includes: extraction with methylene chloride; sonication to break up sediment-extractant-water emulsions; drying over sodium sulfate (Na2SO4); concentration with Kuderna-Danish apparatus; transfer to isooctane; and splitless injection into two capillary columns equipped with nitrogen-phosphorus thermionic detectors. The procedure provides quantification of the following pesticides: linuron, EPTC, butylate, ethoprop, trifluralin, phorate, simazine, atrazine, terbufos, fonofos, diazinon, cyanazine, metribuzin, alachlor, metolachlor, chlorpyrifos, penoxalin, and two atrazine metabolites. The dual column injection allows simultaneous confirmation of 14 of the compounds listed above.
The quality control (QC) program relies heavily on automated features of the analytical system. An autosampler allows analyses of a large number of QC samples including recalibration standards, blanks, replicates, spikes, and linearity checks. A data acquisition system provides chromatograms and detailed data reports for both capillary columns. Automatic transfer of the data reports to a computer system facilitates data quality review and data correction. The analytical procedure and associated quality control program provide an effective method for analyzing the large number of samples required in pesticide loading studies during runoff events in large rivers.
Establishing Destruction Efficiency for Hazardous Waste Incinerators
Authors: Colby BN , Picker JE 
Published: December 2008

The expansion of technology has brought a critical need to dispose hazardous wastes safely and permanently. The historic approaches to disposal, such as land filling, discharge into waterways, and deep well injection have begun to exhibit severe environmental and human health safety problems. These in turn have resulted in legislation such as the Clean Water Act, the Toxic Substances Control Act, and the Resources Conservation and Recovery Act, all of which regulate and establish responsibility for hazardous materials. One universally desirable feature in hazardous waste disposal is once-and-for-all destruction of the waste. Incineration (i.e., thermal oxidation) is considered by many to offer this feature. There is, however, a need to demonstrate destruction efficiency in order to satisfy environmental regulations and to aid in public acceptance of the process.
Establishing incineration destruction efficiency for regulatory compliance is a challenging technical problem owing to the variety of sampling and analysis techniques which may be involved. It is also a challenging documentation problem owing to the potential for “concerned citizen” initiated litigation. Both of these problems require application of sound quality assurance (QA) protocols in order to generate destruction eficiency data of known and documented quality. It is these QA protocols which are the subject of this presentation. Issues addressed include the representativeness of samples and sample collection, the precision and accuracy of analytical methods and destruction efficiency calculations, and the documentation associated with establishing data quality. Emphasis is placed on those QA approaches that can be applied to data sets of limited size normally associated with incineration destruction efficiency evaluations.
Establishing an Environmental Quality Assurance Program
Authors: Eggenberger LM 
Published: December 2008

Specific steps leading to the establishment of an Environmental Quality Assurance Program in an analytical laboratory are enumerated and discussed. Aspects of a model Quality Assurance Program that applies fundamental principles and methods to selected laboratory instrumentation and analytical protocols for the attainment of accurate, reliable results are reviewed. Discussion includes specific factors such as method validation, certification, sample handling, security, documentation, and continuing data assessment.
Objectives and problem areas characteristic of newly implemented programs, such as building a data base, interim control limits, reference standards, and categorizing and prioritizing prospective control areas, are included in the discussion.
Effects of Compaction Temperature and Effort on the Engineering Properties of Asphalt Concrete Mixtures
Authors: Kennedy TW , Roberts FL , McGennis RB 
Published: December 2008

In recent years there has been a trend toward operating asphalt plants at lower mixing temperatures. These lower temperatures result primarily from a desire to conserve the energy required to produce the mixtures. The most direct result of lower mixing temperatures is lower temperatures during compaction. The effect of these lower compaction temperatures on performance has not been established, but laboratory studies have led to some questions that need to be addressed. The purpose of this paper is to summarize the results of a field and laboratory study performed at The University of Texas at Austin, Center for Transportation Research, to analyze the effect of lower compaction temperatures on the engineering properties of asphalt concrete mixtures.
Both the field and laboratory studies were conducted as part of an investigation of premature distress of a recycled asphalt concrete overlay. It is significant to note that field observations, as well as laboratory results obtained during construction, indicated that the specified laboratory densities were attained. Even though other factors contributed to the distress, data developed as a part of this study showed that the low compaction temperatures during construction had an adverse effect on the engineering properties of the asphalt concrete and thus contributed significantly to the development of the premature distress.
The field study included examining the construction records to evaluate factors, such as mixing and compaction temperatures, as well as density and Hveem stability of job control laboratory specimens. In addition, a condition survey was performed to determine the nature and extent of the observed distress.
The laboratory study involved preparation of specimens under different combinations of compaction temperature and density observed in the field with subsequent testing to determine Hveem stability, and dry and wet static tensile strengths. The results presented in the paper include a discussion of the interaction between compaction control parameters and the occurrence of distress. Results from these studies indicate that lower mixing and compaction temperatures produce adverse effects on the engineering properties of hot mixed asphalt concrete.
Pennsylvania's Experience in the Compaction of Asphalt Pavements
Authors: Kandhal PS , Koehler WC 
Published: December 2008

During 1974 through 1977, premature pavement distress in the form of loss of fines (matrix) and ravelling (loss of aggregate particle larger than 6.35 mm [¼ in.]) was observed on several asphaltic concrete overlay projects in Pennsylvania. Statistically designed detailed investigations were conducted to determine the cause of this premature distress. Cores 152 mm (6 in.) in diameter were obtained at random and tested for density, air void content, mix composition, and rheological properties of the recovered asphalt. Lack of adequate compaction (high air void content) was determined to be the primary cause of distress. Nuclear control-strip techniques were used on these projects for compaction.
The following data obtained from these investigations are included in the paper: (1) correlation of air void content with the extent of loss of fines and ravelling (rated as none, slight, moderate, and severe from field observations) and (2) correlation between the percent compaction data obtained by two methods (core density and nuclear gage density) at the same locations on the distressed pavements.
Statistical analysis of the data from these projects indicated that (1) the percent compaction just after construction should be at least 92% of the maximum specific gravity of the mix to prevent the premature distress in the pavement and (2) the nuclear gage cannot be relied on completely by the user agency for acceptance purposes; it is most suited for compaction quality control by the contractor during construction.
A statistical (end result) specification for compaction was developed and implemented by the Pennsylvania Department of Transportation in 1978. Density cores are obtained and tested at the central laboratory. The adoption of this compaction specification has resulted in a very significant improvement statewide in the initial compaction levels of asphalt pavements. The paper gives the outlines of this compaction specification, test procedures, and implications. The data on actual compaction levels (based on approximately 6000 core tests) achieved statewide in 1981 have been analyzed statistically for both binder and wearing courses.
Effect of Percent Compaction on Asphalt Mixture Life
Authors: Bell CA , Hicks RG , Wilson JE 
Published: December 2008

One of the major difficulties in asphalt concrete pavement construction is the control of materials and the subsequent level of payment to contractors for materials not conforming to specifications. The effect of this noncompliance on pavement serviceability is not fully established; however, it frequently results in reduced payments to contractors, which, in turn, causes much controversy between the two parties. Specific mixture properties outside specification tolerance, which are accepted by most agencies through reduced payment include percent compaction, asphalt content, and mix gradation. The reduced payment used normally relies heavily on the experience and judgment of the agencies; therefore, there is often wide disparity in the pay adjustment factors used.
The paper summarizes currently available techniques for estimating the modulus and fatigue life of asphalt mixtures and shows how these, together with existing failure criteria for fatigue and permanent deformation may be used to estimate the effects of changes in compaction on pavement life. Secondly, the results of extensive laboratory tests on asphalt mixtures from three projects in Oregon are reported. Tests were performed to evaluate the effect of mix variations (including density) on mix properties (modulus, fatigue life, and resistance to permanent deformation). Tests were run using both as-compacted and conditioned (vacuum saturated followed by freezing then heat soaking) specimens. The test used throughout was the ASTM Repeated Load Diametral Test (D 4123-82) modified slightly such that fatigue life could be evaluated.
The results of the test program indicated that percent compaction (or void content) was the most significant factor affecting mix performance. An increase in void content is associated with a decrease in modulus, fatigue life, and resistance to permanent deformation.
The result of the study findings was the development of new asphalt concrete compaction specifications for the state of Oregon. Not only does the Oregon Department of Transportation (DOT) now require a higher standard of compaction (91% of American Association of State Highway and Transportation Officials [AASHTO] T209 maximum specific gravity), but they have also spelled out clearly the penalties for not achieving density.
Precision of Electrorefined Copper Assaying
Authors: Parr JC , Braithwaite JW 
Published: December 2008

A principal measure of the quality of electrorefined copper cathodes is impurity content. As such, good analytical precision is needed to identify subtle improvements in quality and to ensure that industry specifications are being satisfied. The object of this study was to determine and document the current state of refined copper analytical precision. Three levels of precision were evaluated. The highest level was determined from the sequential analyses of over 100 wire rod samples. The implications of this precision on both impurity specifications and actual content in cathodes are discussed. The study of the day-to-day precision and long-term precision among several laboratories was determined from analyses made on standard samples. A statistical comparison of the long-term and sequential data is given.
Based on the data presented in this paper, two areas of refined copper assaying which require improvement are evident: (1) precision of long-term interlaboratory analyses of many elements and (2) detection limits for others. If appropriate analytical accuracies and precisions are to be achieved, substantial progress in analytical methodology will be required.
Mode I Stress Intensity Factors for Point-Loaded Cylindrical Test Specimens with One or Two Radial Cracks
Authors: Parker AP , Andrasic CP 
Published: December 2008

Weight (or Green's) functions are obtained, using an accurate modified mapping collocation numerical technique, for cylindrical specimens with either one or two internal or external radial cracks. Radii ratios (the ratio of external/internal radius) of 1.25, 1.5, 1.75, 2.0, 2.5, and 3.0 are considered. The weight functions are used to obtain stress intensity (K) factors for radial loading by point forces symmetrically located about the crack line and about an axis at right angles to the crack line, through the center of the specimen. The maximum errors associated with the solutions are estimated at 1%.
Notable features of the results obtained include a significant range of crack lengths with near-constant K-values, and configurations in which K changes sign as the crack length is increased. The point force configurations are suited to serve as cylindrical test specimens, either for fracture toughness or fatigue crack growth testing.
Geometry and Size Effects on J-R and δ-R Curves under Plane Stress Conditions
Authors: Hellmann D , Schwalbe K-H 
Published: December 2008

J-R curves and δ-R curves were measured on 5-mm-thick compact, three-point bend, and center cracked tension specimens with different widths and different precrack lengths. The crack tip opening displacement (δ) was measured at the fatigue crack tip. The materials tested were an age-hardened aluminum alloy; the same alloy in a furnace cooled, very soft condition; and an alloy steel. It was found that the J-integral correlates three to five times as much crack growth in the tension specimens as in the compact and bend specimens, or, in other words, a valid R-curve detemined on a center cracked tension specimen covers at least three times more crack growth than a valid R-curve determined on a compact or bend specimen of the same width and crack length. Furthermore, δ correlates even more crack growth: a valid δ-R curve determined on a compact or bend specimen covers about five times more crack growth than a valid J-R curve. For center cracked tension specimens the amount of crack growth measured was not sufficient to establish limits for a valid δ-R curve; however, at least 60% of the original ligament width can be expended by crack growth for a valid δ-R curve.
It is worth noting that no geometry effect on the J-R curve and δ-R curve was found as long as the R-curve data could be considered “valid.”
Influence of Loading Rate on the Fracture Toughness of Some Structural Steels in the Transition Regime
Authors: Marandet B , Phelippeau G , Sanz G 
Published: December 2008

The fracture toughness of five structural steels was determined as a function of temperature in static and dynamic conditions (˙K ≈ 2 × 104 MPa √m/s). The most significant effect of increasing the strain rate was to shift the KIc-temperature curve towards higher temperatures. The amplitude of the temperature shift between the transition temperatures obtained in static (TKIc) and dynamic (TKId) conditions were compared with the predictions given by different models. It appeared that the variations of yield strength cannot always account for the change of fracture toughness with temperature and strain rate.
A correlation between Charpy V-notch (CVN) transition temperature (TK 28) and dynamic toughness transition temperature (TKId) was established. This correlation is an extension of the one proposed previously between TK 28 and TKIc. Assuming that fracture toughness transition is a thermally activated process, it was possible to calculate theoretically the slopes of the correlations; these were found to be in good agreement with the experimental results.
Droplet Analysis Techniques: Their Selection and Applications
Authors: Bachalo WD 
Published: December 2008

Drop size measurement instrumentation is being developed to provide a reliable and accurate means for obtaining drop size data with a minimum expenditure of time. The physical principles involved in the measurement concepts are relatively complicated. Thus, the instrument selection process becomes difficult without at least a general knowledge of the selection criteria, available concepts, and their inevitable limitations. At the same time, there are a broad range of applications with specific measurement goals to be met. The measurement requirements include drop size range, spatial and temporal resolution, and the determination of mass flux. Drop shape can be also an important factor when measuring large droplets that may distort under the prevailing aerodynamic forces. Measurements are further complicated by the need to obtain the results in difficult environments.
In this paper, a general review of drop size measurement applications is given with discussions of the associated conditions affecting the measurements. The descriptions of the measurement conditions and requirements are then related to the corresponding instrument capabilities. An overview of the measurement concepts most commonly used is given and the respective capabilities discussed. Techniques based upon both optical and material probe concepts are considered. The information outlined is intended to provide a guide to the evaluation and inquiries that should be made during the selection of a drop size measurement instrument.