bluuebunny/crossref_metadata_2025_split huggingface dataset:
Significance of Transformer Oil Properties
Authors: Pearce HA 
Published: February 2009

Transformer oil is a refined mineral oil obtained from the fractional distillation of crude petroleum. It is then treated to remove impurities and to obtain the most desirable properties to make it suitable as an insulating and cooling liquid.
The most important property for an insulating liquid is the high dielectric strength and for a cooling liquid the low viscosity. Other properties are important to show the absence of impurities and to show the degree of stability for long life. Properties indicating purity are also important in the consideration of the ability of the oil to be compatible with the other materials used in transformer construction.
The primary enemies of the transformer oil are oxidation, contamination, and excessive temperature. Processing and transformer construction are designed to minimize the effect of these enemies, and tests are conducted to evaluate these considerations.
ASTM Specification for Mineral Insulating Oil Used in Electrical Apparatus (D 3487) has been designed to cover the properties of transformer oil for use as an insulating and cooling medium. Quoting its scope: “This specification is intended to define a mineral insulating oil that is functionally interchangeable and miscible with existing oils, and is compatible with existing apparatus and with appropriate field maintenance, and will satisfactorily maintain its functional characteristics in its application in electrical equipment.”
Much effort is expended by manufacturers to obtain and maintain quality oil for use in their equipment.
A Review of the Operating Principles and Practice of Dissolved Gas Analysis
Authors: Haupert TJ , Jakob F 
Published: February 2009

Dissolved gas analysis has gained worldwide acceptance as a method for the detection of incipient faults. When properly applied, the method provides a highly reliable and sensitive method for the identification of fault type and for the assessment of the rate of fault development.
This paper investigates the origins of the individual fault gases, factors that are responsible for the extreme sensitivity of the method, and the factors that influence the observed gas concentrations. The paper also examines the scope and limitations of the diagnostic techniques that have been developed to interpret the data that the method provides. These techniques include such concepts as key gases, ratios of gas concentrations, nomographs, and rates of gas generation.
Development and Validation of RCRA Method 8280 for Dioxins and Furans
Authors: Billets S , Ballard JM , Vonnahme TL , Nunn NJ , Youngman DR 
Published: February 2009

RCRA Method 8280 for the analysis of chlorinated dibenzo-p-dioxins and dibenzofurans, as published in the Federal Register in April 1983, revealed the need for several modifications to allow for the determination of the target analytes in complex matrices, such as industrial sludge and still-bottom samples. Details of these modifications and of the subsequent application of the revised method to a limited number of samples which were analyzed in the course of a multilaboratory evaluation are reported.
Further evaluation of RCRA Method 8280 for the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans has been performed. The Method has been modified to provide for the quantitation of total tetra- through octa-chlorinated dioxins and dibenzofurans and has been applied to sample matrices derived from industrial polychlorophenol sources as well as to fly-ash, still-bottom, and Missouri soil samples. As an additional test of Method performance, an interlaboratory validation study was conducted in two parts. A two-part study was used because the Method had been extensively revised since its publication in the Federal Register, and it was felt that participating laboratories would be unfamiliar with some of the proposed procedures. The first phase was intended to allow the participants to acquire familiarization with the Method by analyzing relatively simple matrices for a few specified analytes which had been spiked into the samples. The second phase required the total quantitation of tetra- through octa-CDDs and CDFs in complex samples containing the analytes at both low (ppt) and extremely high (ppm) levels; no spiking was used for these samples. A method detection limit study using all available 13C12-labeled PCDD and PCDF isomers spiked into seven different sample matrices was also performed, and the results indicated both matrix and homolog specific differences.
The revised Method 8280 has undergone a period of continual development; new documentation which will be reported includes Method performance data on complex samples from polychlorophenol use processes, results from an interlaboratory study of the revised method, and method detection limits of selected PCDDs and PCDFs in a variety of environmental and hazardous waste matrices.
Interlaboratory Evaluation of ICP-AES Method 6010
Authors: Hinners TA , Jones CL , Biesiada JH , Schoengold DM , Starks TH , Campana JE 
Published: February 2009

EPA Method 6010, inductively coupled plasma atomic emission spectroscopy (ICP-AES), is undergoing interlaboratory evaluation for sludge-type wastes. The wastes included in the study are furnace ash, treatment sludge, mine waste, electroplating sludge, as well as contaminated soil and sediments. Twenty-three elements will be determined by conventional ICP-AES in digests of the spiked and unspiked waste materials.
The raw wastes as well as bulk digests will be analyzed by all participating laboratories so that the variation contributed by sample preparation can be distinguished from the variation contributed by the measurement process. Both sequential and simultaneous instruments will be used in the study to allow an assessment of performance as a function of instrument type. The study will include an analysis of variance to characterize the homogeneity of each waste material before distribution to the participating laboratories. Heterogeneous materials are not suitable for interlaboratory studies.
Method 6010, Version 1, includes quality control tests to assess the data quality. If the results for diluted samples or for spiked digest are not within the control limit of ±10% specified for this study, the method of standard additions is required to provide data of acceptable quality. For this interlaboratory study, a four-point method of standard additions is specified to allow a least-squares analysis to obtain the sample concentrations. Use of alternate wavelengths is recommended to confirm data quality when spectral overlap could be present.
While Method 6010, Version 1, will accurately reflect the element quantities solubilized by the digestion procedure used, it will not reflect the waste content of an element when components in the waste form insoluble compounds (such as barium and lead with sulfate). However, the quality control spike addition in Method 6010, Version 1, will indicate a data-quality problem for affected elements in such a situation so that data of known quality are obtained. Methods that are applied directly to solids (such as neutron activation analysis and X-ray fluorescence analysis) are called for to assess waste content (but not availability) when solubility limitations are present.
Quality Assurance on the Groundwater Monitoring Task Force Facility Assessment Program
Authors: Kangas MJ , Tyburski TE , Duchene JA , Friedman PH 
Published: February 2009

The U.S. Environmental Protection Agency (USEPA) Hazardous Waste Ground-Water Task Force (HWGWTF) is conducting under its Facility Assessment Program groundwater sampling at 58 sites where commercial land disposal facilities are located to determine whether or not these facilities are contaminating groundwater with hazardous wastes. Laboratory analyses of groundwater samples from these sites are being performed for organic compounds and metal, inorganic, and indicator parameters. This paper provides an overview of initial quality assurance (QA) activities applied to these analyses.
A Data Evaluation Committee (DEC) consisting of HWGWTF members from USEPA headquarters, regional offices, and Office of Research and Development (ORD) laboratories provides QA overview for Facility Assessment Program activities. The DEC developed a Quality Assurance Project Plan (QAPP) specifically for the Facility Assessment Program. The QAPP establishes data quality objectives (DQO) which define the quality of the data desired from the groundwater sampling and analytical efforts. These DQO address data accuracy, precision, representativeness, completeness, and comparability. The QAPP also defines roles and responsibilities of HWGWTF members and contractors and procedures to be followed in achieving the DQO.
This paper provides an overview of QA activities performed by the HWGWTF DEC and technical support contractors during evaluation of the first six facilities sampled under the program (Phase I) and provides examples of improvements planned for subsequent QA efforts based on experience gained during Phase I. The evaluation of analytical quality control (QC) data and laboratory performance through integration of information from performance evaluation samples, analytical chemistry audits, statistical summaries, and control charts for analytical data generated by Superfund Contract Laboratories is described.
Overview of Crack Closure at Near-Threshold Fatigue Crack Growth Levels
Authors: Liaw PK 
Published: February 2009

The effects of microstructure, environment, loading condition, and crack size on near-threshold fatigue crack growth rate properties are briefly reviewed. It was found that the concept of crack closure could generally be used to explain these effects. Furthermore, structural materials with superior fatigue threshold resistance can be developed by promoting crack closure through microstructural control.
Realizing the importance of crack closure at threshold levels, crack closure measurements need to be standardized. Particularly, the relationship between far-field and near-tip crack closure measurements has to be investigated. With a rapid progress in experimental measurements and analytical modeling of crack closure, it is our hope that in the near future fatigue life of structural materials can be more accurately predicted by incorporating crack closure models.
Crack Closure: Correlation and Confusion
Authors: Hertzberg RW , Newton CH , Jaccard R 
Published: February 2009

Some aspects of crack closure are reviewed and examined with respect to one's ability to predict fatigue crack propagation rates in engineering alloys. The development of artificial crack closure with the placement of shim stock in the crack mouth provided nonconservative estimates of crack growth rates as compared with those rates for specimens influenced by natural closure processes.
A reevaluation of the ΔK-decreasing (constant stress rati o) test procedures suggests that this method may introduce abnormally high closure levels and generate nonconservative values of ΔKth. The implication of comparing such long crack data with results from short crack samples is discussed.
Effects of Load History and Specimen Geometry on Fatigue Crack Closure Measurements
Authors: Ashbaugh NE 
Published: February 2009

The effects of simple load histories and specimen sizes on crack closure measurements are presented. Tests are conducted on compact type C(T) specimens having various thicknesses and in-plane dimensions. The simple load histories are composed of constant amplitude load and stress intensity ranges. Closure load is determined from data collected from three measurement techniques. A clip gage is used to determine the load-displacement behavior at the crack mouth. A strain gage placed on the backface of the C(T) specimen is used to determine the load-strain behavior. The third technique uses a laser interferometric displacement system where load-displacement data are collected at various locations on the side of the specimen in the vicinity of the crack tip.
The results indicate that the closure load determined by the interferometric system at various locations along the length of the crack is not uniquely determined. Even though the interferometric technique provides a resolution of displacement less than 0.01 μm, the sensitivity of the technique impacts the evaluation of the closure load. Under constant amplitude stress intensity loading conditions, the values of the closure load varied with crack length and with in-plane and thickness dimensions of the test specimens.
Closure Measurements on Short Fatigue Cracks
Authors: Lee J-J , Sharpe WN 
Published: February 2009

Single-edged notched specimens, 2.3 mm thick, of 2024-T3 aluminum were cyclicly loaded at R ratios of 0.5, 0.0, −1.0, and −2.0. The notch roots were periodically inspected with an optical microscope and with acetate replicas in order to locate the initiation of very short cracks. The loads were selected to produce fatigue lives of 500 000 cycles or less. The specimens and the load schedules were part of an AGARD-sponsored, round-robin test program designed to study the growth of short cracks.
As an addition to the AGARD program, crack opening displacements were measured at single positions across cracks as short as 0.035 mm and as long as the full thickness of the specimen. Two small reflective indentations were placed across the short crack and illuminated with a 15-mW He-Ne laser. This formed interference fringe patterns that could be monitored to measure the relative displacement between the two indentations. Fringe motion was monitored with a minicomputer-controlled optical scanning system to produce real-time crack opening displacements.
The opening load ratios for the short cracks are somewhat smaller than those for long cracks at positive R ratios but are considerably smaller for negative R ratios. The measured compliances of the very short cracks increase linearly with increasing surface crack length and agree quite well with the predictions of linear elastic fracture mechanics.
Analysis of Fatigue Crack Closure Caused by Asperities Using the Modified Dugdale Model
Authors: Nakamura H , Kobayashi H 
Published: February 2009

Crack closure characteristics in fatigue crack growth were examined using the modified Dugdale model developed by Newman. The model can leave elastic-plastic asperities in the wake of the growing crack tip. The analysis showed the influence of the rigidity E of the asperities, asperity length, asperity thickness, and the distance from the crack tip.
The validity of the unloading compliance technique was examined. The analysis showed a guide of how to determine the crack opening point. When the plasticity induced crack closure prevails, the detected crack opening point gives the correct information regarding the actual one. The crack opening point, rather than the closure point, determined in this way is a useful parameter to describe the crack growth rates.
Under some closure mechanisms, however, it is pointed out that this technique may not be useful. Especially, when asperities are attached near the initial notch tip like under corrosive environment, the crack opening point becomes an overestimate of the actual level. On the other hand, when they are attached near the crack tip like near the threshold region in an air environment, it becomes an underestimate.
An analytical procedure was developed to determine the crack opening stress intensity Kop from the contact stress at minimum stress intensity. By using this parameter, the crack tip opening displacement or the crack growth rate is described uniquely.
Problems and Solutions to Masonry Buildings
Authors: Gensert RM , Bretnall WC 
Published: February 2009

The authors have been actively investigating masonry buildings for over 25 years and have documented problems associated with differential movement within masonry systems and between systems and their supporting structures. While they have found many buildings and components which perform well, it has been their experience that masonry buildings with problems have often been brought to the attention of the public without full and in-depth understanding of the source of the trouble.
One cannot analyze a building's problems by a quick visual inspection and a first reading of the drawings and specifications. It is necessary to document all signs of distress as an overlay upon the structural frame. Materials must be sampled and tested for quality and compatibility. Walls must be probed with fiber optic instruments to determine the quality of assemblages and their attachments to the structure. Architectural details, such as drainage, flashing, movement joints, bonding, etc., are important to the well-being of masonry walls and must be examined. Structural support of masonry and its interaction with the supporting structural component and with the structural frame as a whole is also critical in terms of differential movements. The authors have documented this experience by means of photography computer graphics instrumentation, and this paper will share with you the knowledge gained by this work effort.
Influence of Tie Flexibility, Relative Length, and End-Boundary Condition on Brick Veneer-Metal Stud Flexural Bond Stress
Authors: Chin IR , Krogstad NV , Monk CB 
Published: February 2009

Based on insights from the Clemson test report on the wall system under discussion, the authors analytically examined the issue of the relative stiffness between the brick veneer and the metal stud.
Much controversy has surrounded the contention that the inherent stiffness of the brick veneer will result in critical flexural bond stresses in the veneer when laterally supported on metal studs. Using ordinary conventional relative stiffness methods of analysis, the brick veneer can attract 85% or more of the wind load, whereas the metal studs attract 15% or less. Even if the studs are designed to take full wind load at a span-deflection ratio of 360 to 600, ordinary analysis may still indicate that critical flexure bond stresses will occur in the veneer prior to full participation of the stud.
This paper shows that if the inherent tie flexibility, normal shorter metal stud length, and usually free top boundary wall condition are taken into account, critical flexural bond stresses do not exist in the brick veneer on typical brick veneer/metal stud walls. Recommendations on the utilization of inherent boundary conditions to minimize the development of critical flexural bond stresses in the veneer are presented.
Analysis and Test of a Torsional Sensitive C-Shaped Prefabricated Brick Spandrel Panel
Authors: Arnold RC , Dondanville LJ , Krogstad NV , Monk CB 
Published: February 2009

Recognizing the inherent torsional flexibility of an open C-section, the authors analyzed in detail the dead and live load behavior of the section under review. The section consisted of a sloping sill, a vertical spandrel, and a horizontal soffit configuration fabricated as a continuous bent plate. The three planes when joined together form an open C-section. To explore the stress patterns in this shaped plate, the authors modeled the analysis for a hand solution. This was then compared to a more rigorous solution using a finite-element computer approach.
The hand approach determined the principal axes of inertia, the shear centers, and the principal states of stress by Mohr's circle. Comparison is shown with graphic plots of principal stresses from the finite-element analysis. The latter technique makes a detailed investigation possible, including plots of both principal tensile and shearing stresses. The modeling of the complex metal embedments at each reaction location was also possible by the finite-element solution.
Full-scale testing of the panel was made utilizing dead weight from brick loading platforms that exerted gravity and wind loading on the spandrel panel through a series of compound lever frames. Contrary to results of brittle torsional failure expected from the analytical work, the experimental behavior demonstrated a capacity to a load factor of five without cracking or collapse.
Test of Model Masonry Single Pier Under Dynamic Shaking and Quasistatic Cyclic Loading
Authors: Chen H-L , Shah SP 
Published: February 2009

In order to improve seismic design of masonry structures, research is needed in the area of masonry response to seismic loading. One of the purposes of this program is to investigate the difference of the structural response of masonry single pier when in-plane shear force is applied dynamically and slowly. In addition, modeling techniques for brick masonry were studied.
The experimental results are reported for the structural behavior of two brick masonry piers under dynamic shaking and slowly applied cyclic loading. Each specimen was an unreinforced model pier having a height-to-width ratio of 1 with fixed-end conditions. The model was constructed of one fourth scale brick and mortar composed of fine sand, lime, and cement. Compressive tests of model mortar cubes, prisms, and one square panel were done to understand the modeling techniques of brick masonry. It was found that the piers under dynamic shaking are characterized by localized failure and abrupt stiffness degradation. However, the peak strength was lower under dynamic shaking. This tentative, preliminary conclusion should be verified with further tests.
In-Situ Evaluation of Compressive Stresses
Authors: Manmohan D , Schwein RL , Wyllie LA 
Published: February 2009

The use of terra cotta as a cladding material emerged in the 1880s and began to decline in the late 1930s. During this period, high-rise buildings employing terra cotta cladding included no provisions for differential movement between the cladding and structural framing. Numerous terra cotta clad buildings are showing signs of distress due to weathering and induced stresses from frame shortening under load. Determination of residual compressive stresses within the terra cotta cladding is often necessary for evaluation and repair of the distressed material.
The level of stresses induced in the cladding of a high-rise building in San Francisco was measured by performing strain relief tests. Uniaxial strain gauges were adhered vertically to the face of the terra cotta blocks and initial balance readings were obtained. The mortar bed joints were sawn along the terra cotta units and the strains monitored during and after the cutting. Samples of the terra cotta block were cut, instrumented, and tested in compression to determine elastic properties and ultimate compressive strength.
Having obtained the physical properties of the terra cotta, compressive stresses due to frame shortening in the structure were determined. Strain data obtained indicated stress levels which were low enough to eliminate the need for stress relief. Optimum saw cutting locations were determined had stress levels been high enough to require stress relief.