bluuebunny/crossref_metadata_2025 huggingface dataset:
Flammability—A High Tech Packaging Issue
Authors: Crowley DP
Published: February 2009

A discussion is presented on the importance of considering the flammability of packaging materials when designing fire protection for high tech storage operations as seen from a risk management perspective. The high dollar value of such products, and the relatively high flammability of packaging materials used to protect them, combine to create serious warehousing fire risks. Traditional sprinkler protection philosophy is based on “fire control,” that is wetting down a specific area (185 to 280 m2), to slow down fire development and allow the fire department to extinguish the fire. This philosophy, though adequate for many warehouse applications, can be inappropriate for high tech warehouses, as the fire dollar loss may be excessive even with successful control of a fire. More effective sprinkler systems are described. However, the pursuit of improved fire protection methods to cope with increased packaging flammability challenges is not the total solution. More important is the pursuit of lower flammability packaging materials to reduce the fire risks in the first place. A description of current developments in low flammability packaging materials, including corrugated paper containers and foam plastic cushioning materials, is presented. Packaging trends are forecasted.
Predicting Minimum Cushion Thicknesses
Authors: Fiedler RM
Published: February 2009

The required minimum thickness of protective package cushions is predictable and can be calculated easily based on available data and fundamental engineering principles. The minimum cushion thickness is dependent on the product fragility, the design drop height, and the cushion efficiency. Minimum package dimensions and densities can be established prior to the development of prototype package designs and before the selection of packaging materials. This provides information needed to address package dimension and cost constraints for various product fragility levels. Cushioning materials can be directly compared based on their efficiency ratings that are easily derived from data normally presented in cushion curves for cushion materials. Examples of the relationship of these variables are presented along with the general equations. Cushion efficiency ratings are discussed and examples derived from published cushion data are reviewed.
Predicting Field Performance from Laboratory Testing
Authors: Sheehan RL
Published: February 2009

Laboratory testing of packages is useful to help an engineer determine if a package and its contents are likely to survive hazards encountered during shipment. The severities of physical distribution hazards, such as the heights of handling drops, are not constants but rather are understood best from a probabilistic viewpoint; package performance also may have significant variability in response to controlled laboratory dynamics. Making the connection from package testing to field performance can be accomplished by the development of quantitative models that may be simulated on a computer. These models add to the understanding of the system; they are useful to investigate the projected effects of alternate assumptions and of inherent uncertainties. The models discussed in this paper relate to a package or its product being damaged by shock resulting from a drop.
A Comparison of Three Different Cushion Test Methods
Authors: Schueneman HH
Published: February 2009

In a classroom environment, three different cushion test procedures (MIL-P-26514E, ASTM Test Method D 1596, ASTM Test Method D 4168) were used as the basis of package designs. The packages were tested and the results compared to the design criteria. Differences in results were related to how the various test procedures describe cushion performance. A suggestion is made to use test procedures that give both material comparison data and creditable package design information.
Some Field Problems with Thin Veneer Building Stones
Authors: Bortz SA , Erlin B , Monk CB
Published: February 2009

The authors, in examining experiences with over 40 stone veneer buildings over the past decade, describe typical problems that have arisen in the use of limestone, travertine, marble, and granite.

The modern trend to thinner ornamental dimensional stone has resulted in the use of thicknesses down to 2 to 3 cm (7/8 to 1 3/16 in.)—a significant reduction from 5.08 to 7.62 cm (2 to 3 in.) that was regarded as a lower practical limit less than ten years ago. The authors examine the consequences of such thin stone veneer in terms of strength, durability, and architectural engineering performance. Material geology, quarrying and fabrication limitations, and environmental factors are considered.

Specific field problems encountered have included a variety of structural, architectural, petrographic, and erection problems. Structural problems have included torsional twisting or thin deep beam participation at spandrel beam locations. Architectural problems have embraced differential movement or water permeability issues that affect expansion joints of internal drainage systems. Petrographic work has examined the bowing of thin marble or the weathering of travertine. Erection has involved workmanship issues (including plant fabrication considerations) or field material handling and attachment techniques.

The authors conclude with a recommended list of design criteria to avoid future problems of the kind they have encountered.
Design Considerations for Using Stone Veneer on High-Rise Buildings
Authors: Gere AS
Published: February 2009

Due to substantial advancement of quarrying and fabrication methods, natural building stone has become available in thinner slabs in a wide variety of finishes, shapes, and sizes and has also become relatively less expensive than some of the other building cladding materials, which producers were forced to keep raising prices for due to the energy crisis of the 1970s.

This relatively low fabrication cost, together with the development of the various suspension systems and the advancement of the fabrication technology of anchoring components, makes the durable and relatively maintenance-free natural building stone more desirable to use to clad the increasing number of high-rise buildings built worldwide.

But, together with increased use of building stone, the number of expensive failures are also increasing. Sometimes facade failures can endanger public safety, and the cost to repair or reconstruct distressed stone facade can exceed its original cost.

The author, during the last 30 years, has investigated numerous miscellaneous types of failures of building stones of sedimentary, metamorphic, and igneous origin on building facades, as well as on exterior plaza installations.
Selection, Purchase, and Delivery of Building Stone—the Obstacle Course
Authors: Heinlein M
Published: February 2009

This paper discusses the relationship of the stone testing and evaluation procedures to the overall contract for stone curtain walls, construction scheduling, and quality control. Examples of three recent buildings in New York City will be used to illustrate the subject.
Design Criteria for Thin Stone/Truss Wall Systems
Authors: Benovengo EA
Published: February 2009

The stone industry has experienced little change in construction practices over the last century, save the events of the last five years. The area of acute recent activity has been the advent of new, sophisticated stone-cutting systems. The offspring of this is the production of building stone of great face size with stone thicknesses of mere centimeters in lieu of inches. The thin stone panels can become an efficient stone envelope system when joined by dedicated support and other envelope components, thus creating a stone envelope assembly with obvious advantages over conventional stone construction.

The challenge for the design professional is two-fold in considering the use of thin stone wall systems. The initial challenge is one of aesthetics and design flexibility. The latter and more demanding challenge is the appropriate selection of materials, components, and assemblies to produce an integrated building envelope system which satisfies the particular criteria of the selected project. A primary need is the proper linking of expectations and capabilities.

The performance criteria established by the design professional will require a systematic review of materials, componentry, and performance criteria including stone properties, anchorage systems, material compatibility, joint treatment, code limitations, and thermal, air, water, and moisture control systems. Additional concerns focus on limitations imposed by thin stone wall systems to the project design and construction.
Truss Supported Stone Panel Systems
Authors: Gulyas S
Published: February 2009

The truss-supported stone panel evolved during the last 20 years from simple strongbacks to entire prefabricated building bays. The advantages of prefabrication assure higher quality at competitive cost. The development of the many types of truss panels was dictated by the various characteristics of specific buildings. These panels can take practically any form, from strongbacks to spandrel and window truss panels, column truss panels, full wall panels, and specials. The panel is assembled with the truss in either vertical or horizontal position. The type of assembly greatly influences the type of stone anchor system to be used. A variety of stone anchor systems have proven value. The steel truss panels themselves need special connections to the supporting building frame to accommodate the various building movements without transferring forces to the truss panel. Design, proper installation, and inspection of such connections are vital. Full-scale mock-ups should be built for testing and feasibility of construction. The possibilities of the prefabricated stone panel systems are great, but they require vigilance and professional planning.
Stone Veneer-Faced Precast Concrete Panels
Authors: Freedman S
Published: February 2009

In the 1960s, the use of stone veneer-faced precast concrete panels became prevalent. As stone veneer becomes thinner, greater emphasis on stone physical properties becomes important as well as examination of factors of safety. A survey of precast concrete panel producers revealed excellent performance of thin stone veneers over the last 20 years.

The precast concrete industry recommends that there be no concrete bonding between stone veneer and concrete backup in order to eliminate bowing, cracking, and staining of the veneer. Mechanical anchors should be used to secure the veneer.
Stone on Precast Concrete or Steel in Wall Design and Construction
Authors: Kafarowski G
Published: February 2009

After a brief discussion of building stone geology and quarrying, and the cutting/finishing operations, the paper discusses various aspects of the quality control and tolerances of panel construction as they affect the fabricator and erector and ultimately the finished stone panel system.
Posttensioned Panels of Indiana Limestone
Authors: Kluesner HF
Published: February 2009

Posttensioning of concrete for various uses has been standard practice in the construction industry for many years. The engineering principles are well-known. The design of tensioned stone panels utilizes these same principles, and the advantages of posttensioned stone are much the same as for concrete. Most applications to date have been for cladding only. This paper is essentially a summary of experiences on projects utilizing posttensioned units of Indiana limestone for which the author developed the posttensioned designs and plant procedures. It is not intended to be a design manual but to provide a few guidelines for use in adapting well-known posttensioning methods to the design of natural stone units. This paper includes information on design loads, tendon design, allowable stresses, epoxy joints between stones, gravity and retention connections, grouting, fabrication, handling, storage, and transport considerations. It also includes case histories of projects.
Stone Veneer and Glass Fiber Reinforced Concrete Panels
Authors: Lafayette M
Published: February 2009

Glass fiber reinforced concrete (GFRC) may be used to replace conventional concrete backup to stone veneer precast panels, thereby producing a lightweight panel. Toein spring clips connect stone veneer to GFRC backup. A bondbreaker separates the GFRC and stone veneer to allow differential movement. A steel stud frame commonly functions as a panel stiffener. The stud frame is attached to the GFRC skin by means of flex anchors.

The gravity load of the GFRC skin is transferred to the stud frame by two methods: (1) flex anchors only, and (2) gravity anchors in addition to flex anchors. The stud frame is attached to the building structural frame, and the loads of the panel are carried through the stud frame to the panel connection points on the structure.
Structural Silicone Sealants Used to Adhere Stone Panels on Exterior Building Facades
Authors: Carbary LD , Schoenherr WJ
Published: February 2009

Appropriate design criteria need to be established for this new structural sealant application to ensure curtain wall safety and performance. This paper describes methods of adhering stone panels to a building framework with silicone sealant with emphasis on joint design and special considerations for stone substrates. The paper also explains the testing used to warrant adhesion and compatibility and the application techniques necessary for a quality installation.
The Marriage of Glass and Stone
Authors: Smith DS , Peterson CO
Published: February 2009

This article reviews two of the many curtain wall systems available to clad the exterior of medium to high rise buildings with glass and stone: the vertical stopless system and the unitized curtain wall system. These glazing methods utilize aluminum as the structural backbone and glass and stone as glazed panels. The systems' major details are individually analyzed and general recommendations on key areas are made, along with a discussion of preliminary design criteria for stone and glass curtain walls. Finally, advantages of both systems are highlighted.
Industrial Applications of Compositional Analysis by Thermogravimetry
Authors: EL Charsley , SB Warrington
Published: February 2009

The use of modern thermobalances, with high sensitivity, fast heating and cooling rates, and good atmosphere control, has allowed the routine application of compositional analysis using thermogravimetry in solving a wide range of industrially important analytical problems. Using examples drawn from experiences within their laboratory, the authors show how the technique can be extended beyond the traditional areas of proximate analysis of coals and determinations of carbon contents. Less common experimental procedures are described, including the use of reactive gases, and the study of samples in liquid and paste form.
Compositional Analysis by Thermogravimetry: The Development of a Standard Method
Authors: Larkin DE
Published: February 2009

The formation meeting of the task group on Compositional Analysis by Thermogravimetry, under ASTM Committee E 37 on Thermal Measurements was held 30 Oct. 1980. That meeting created a document detailing a test method recently voted on and accepted by ASTM. It will be published as Standard Method E 1131.

The test method outlines a general technique for the analysis of materials by measuring mass loss through several thermal stability ranges. The determination of components based on their volatility provides a compositional analysis by using an inert atmosphere for a portion of the analysis of carbon containing materials and mixtures.

This paper describes the test method and its development to date. Data will be provided from the interlaboratory studies conducted to determine the method's precision and accuracy. In addition, a discussion of the method's application is given.
Thermogravimetric Characterization of Elastomers and Carbon-Filled Rubber Composites for Military Applications
Authors: Macaione DP , Sacher RE , Singler RE
Published: February 2009

A number of elastomeric materials used in Army tank track pads have been analyzed by several thermal analysis techniques including thermogravimetric analysis. More than 50 different materials have been evaluated. In general, the test specimens contained styrene-butadiene (SBR), butadiene (BR), and natural (NR) rubber in mono-, di-, or triblend systems.

Thermogravimetric analysis (TGA) was used to determine the percentage of highly volatile organics, elastomer(s), carbon black, and inorganic residue for each sample. An acetone extracted sample was compared to a nonextracted sample to validate the measurement of highly volatile material. The TGA data illustrated that the percent organic and percent carbon black determinations were quite consistent with the known formulations, but the percentage of inorganics was variable in a number of samples. Ash determinations obtained using larger specimens in a muffle furnace more closely approximated the known values. The DTG curve was used to determine the type of elastomer contained in each track pad. NR exhibited a peak at approximately 365°C (689°F) while SBR, BR, and SBR-BR exhibited a peak at approximately 450°C (842°F). TGA can quantify SBR and/or BR versus NR, but cannot differentiate between SBR and BR, nor can TGA differentiate between cured versus uncured systems. It is necessary to employ differential scanning calorimetry (DSC) to detect uncured systems using the cure exotherm that occurs between 150 to 200°C (302 to 392°F). Finally, the application of thermogravimetric analysis to the tentative identification of foreign track rubber samples is considered.
Determination of the Degree of Mixing of Sheet Molding Compound Paste Using Thermogravimetry
Authors: Kau H-T
Published: February 2009

Sheet molding compound (SMC) technology is used for manufacturing large composite automobile parts. To produce high quality composites, it is important to ensure that the compound paste is uniformly mixed.

A procedure based on thermogravimetry (TG) was developed to determine the uniformity of mixing of SMC paste and of samples molded from the paste. Batches of pastes prepared in the laboratory had a scale of uniformity of 100 μm based on the variance of the inorganic solid (calcium carbonate or CaCO3 filler) content. For paste samples containing a high concentration of volatile component, the accuracy of the analysis was affected by weight loss during the sampling procedure. Premolding the sample was an effective way to overcome this problem and to improve the accuracy.

TG was also used to investigate a procedure for compounding glass flakes in SMC paste. The results showed a high degree of nonuniformity in the slurry material. This was attributed to incomplete wet-out of the glass flakes.
Compositional Analysis of Electrical Switch Contact Carriers
Authors: Pamphilis NA
Published: February 2009

Small amounts of carbon fibers (about 5%) were determined in samples containing polyphenylene sulfide (PPS), inorganic filler (glass in this case), and polytetrafluoroethylene (PTFE) by means of thermal analysis using both thermogravimetry (TG), and differential scanning calorimetry (DSC). Two different, but related, methods were used to quantitatively determine the contents of the sample. The first, which was nominally called the “Indirect Approach,” utilizes DSC for the determination of the polymeric components and TG for the determination of the residue (inorganic fillers or glass or both). The amount of carbon is then determined by difference. The second method, which was nominally called the “Direct Approach,” utilizes DSC for the determination of PTFE and TG for the determination of all other components. The agreement between the two methods is good.
Compositional Analysis Using a New Symmetrical Microthermobalance
Authors: Emmerich W-D , Kaisersberger E , Kelly JE
Published: February 2009

Buoyancy corrections are an important restriction for a precise evaluation of thermogravimetric results achieved with conventional thermobalances. A newly developed thermomicrobalance, designed symmetrically with respect to the arrangement of the balance, furnaces, and gas flow, eliminates buoyancy effects at the thermogravimetry (TG) signal. This instrument allows determination of very small mass changes over a wide range of temperatures. Sample weights in the microgram range result in short reaction intervals. The utility of the instrument for compositional analysis was demonstrated by studying the decomposition characteristics of CaC2O4·H2O and CuSO4·5H2O, and the magnetic transition of nickel for temperature calibration.
A Multielement Evolved Gas Analysis Technique: Design, Performance, and Industrial Applications
Authors: van Leuven HCE , van Grondelle MC , Meruma AJ , de Vos LL
Published: February 2009

A multielement evolved gas analysis technique for the simultaneous determination of up to eight elements is described. The results obtained in one analysis are a quantitative composition in terms of the elements carbon (C), hydrogen (H), nitrogen (N), sulfur (S), chlorine (Cl), bromine (Br), iodine (I) and fluorine (F), and a distribution of these elements as a function of the evolution temperature. Determinations for which the system is used include the amount, composition and volatility of, for instance, kerogen materials, the amount of fixed carbon (coke) on catalysts, or the thermal stability of polymers. The instrument has become an indispensable tool in the screening of materials, in compositional analysis, and in kinetic studies.
The Derivation of Kinetic Parameters in Analysis of Portland Cement for Portlandite and Carbonate by Thermogravimetry
Authors: Bhatty JI , Reid KJ , Dollimore D , Gamlen GA , Mangabhai RJ , Rogers PF , Shah TH
Published: February 2009

The analysis of hydrated portland cement can be facilitated by the use of thermal analysis techniques. This is especially true with regard to the estimation of the portlandite phase (calcium hydroxide [Ca(OH)2]) which is one of the major phases in set portland cements. There are various references in the literature to the use of thermogravimetric analysis (TG) for the estimation of free Ca(OH)2. Papers by Midgley and Ramachandran have shown it to be reliable. It has been used by Dollimore et al. to estimate the Ca(OH)2 in portland cement (OPC), OPC/pulverized fly ash (PFA), and OPC/PFA/polymer pastes. It is also shown here that the method can be adapted to indicate the relative crystallinity of the Ca(OH)2 present. Taking the investigation into a higher temperature region on the thermal analysis equipment also means that an estimate of the calcium carbonate can also be made. This is important in aged mortars. The method can be extended to cover the quantitative analysis of calcium sulfate if present.
From Wood to Coal: A Compositional Thermogravimetric Analysis
Authors: Wiedemann HG , Riesen R , Boller A , Bayer G
Published: February 2009

The carbonization of wood has been studied by means of thermoanalytical methods, in particular, thermogravimetry (TG). This method subjects the sample to a temperature program in a defined atmosphere. The samples were first treated to give a certain degree of charcoal, which could then be analyzed immediately in a second step.

As shown by means of the individual decomposition step of cellulose and lignin, time aging affected the degradation of lignin, whereas thermal aging (the charring process) decomposed the cellulose and turns lignin into charcoal. X-ray analysis showed that because of its chemical structure, lignin turned into paracrystalline coal, a precursor graphite.

In the natural process of carbonization, different kinds of coals such as lignite, bituminous coal, anthracite, or even graphite are formed. TG proved suitable for characterizing these coals by proximate analysis and studying the burning profiles.

Comparable measurements with graphites showed that the combustion rate depended strongly on the composition and structure of the coal.
Compositional Analysis of Solid Waste and Refuse Derived Fuels by Thermogravimetry
Authors: Agrawal RK
Published: February 2009

The disposal of solid waste has become an increasingly difficult and costly problem. Environmental regulations have restricted incineration and ocean dumping, and costs for landfilling have escalated. The calorific value of municipal solid waste (MSW) is about 12.5 MJ/kg on a dry basis (9.8 MJ/kg as received). Therefore, conversion of MSW to marketable fuels has become a noble goal from both an ecological and an environmental standpoint. Typically MSW consists of approximately 60% combustible organics such as paper, newsprint, packing material, wood wastes, yard clippings, food wastes, plastics, and textiles. The remainder is comprised of moisture, glass, metals, and other inorganic wastes. The composition of MSW varies from place to place and on a daily basis. Therefore, there is a need for a method to rapidly characterize these wastes. This communication shows that thermogravimetry (TG) can be used to obtain information on the moisture, cellulosics, plastics, fixed carbon, and ash content of solid wastes and refuse derived fuels (RDF). This procedure is of importance since no ASTM procedures are available to determine the compositions of cellulosic, plastic, and biomass materials. The weakness of the classical ASTM method for proximate analysis of coals and its usage in the biomass area are highlighted. When compared to the classical ASTM method, TG provides additional information on the kinetics and reactivity of materials. Methods for utilizing TG data to obtain information on the composition and reactivity of solid materials are discussed. Broido and Coats-Redfern type equations provide unique Arrhenius parameters.
Thermogravimetry of Selected Clays and Clay Products
Authors: Earnest CM
Published: February 2009

The application of thermogravimetry to the characterization of kaolinite and smectite clay minerals is presented. Examples of differing crystallinity of kaolinites are used. In the study of the smectite clay minerals both dioctahedral and trioctahedral members are included. A unique industrial example of the use of thermogravimetry to follow the cleaning of a bentonite specimen and then its conversion to an organo-clay product, which is used as a component of drilling fluids in the petroleum industry, is demonstrated. Several hectorite specimens representing both raw carbonate bearing clay mineral ores and processed hectorite (carbonate-cleaned) specimens were analyzed by computerized thermogravimetry.
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.
Transformer Fault Gas Analysis and Interpretation—A User's Perspective
Authors: Savio LJ
Published: February 2009

All transformers generate gases during their normal operation as a result of aging and oxidation exclusive of abnormalities. From an operational point of view, it is important to, first, detect and recognize the existance of a problem by observing or detecting deviations from gases considered normal, second, to evaluate the impact on the operation of the transformer (serviceability), and, lastly, to take appropriate action, such as removal from service or increased monitoring frequency. This paper will address these considerations from a utility's perspective using IEEE C57.104 as a guide.
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.
An Engineering Model for Streaming Electrification in Power Transformers
Authors: Roach JF , Templeton JB
Published: February 2009

An engineering approach to assessing static electrification phenomena in power transformers is presented. A theoretical model is developed to estimate streaming currents and space charge accumulation around the hydraulic oil flow loop in a three-phase transformer. The streaming current model is applied to a 345-kV, 240-MVA three-phase auto transformer with shell form winding design. The influence of space charge on the electric field and potential distributions in the upper plenum is modelled by a one-dimensional theory. Significant electric stress enhancement at coil edges on alternate half cycles of applied a-c stress is predicted for the 240-MVA transformer. Potential failure modes in power transformers due to static electrification are discussed.
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.
Hydride Generation Methods for the Determination of Arsenic, Antimony, and Selenium
Authors: Callio SJ
Published: February 2009

Although hydride generation methods have long been used for the analysis of As and Se by AA, very little work has been done on simultaneous hydride generation for the ICP (inductively coupled plasma) environment. This paper will present an outline of the sample preparation and instrumental parameters for the determination of As, Sb, and Se by ICP/hydride. This will be followed by a brief discussion of some quality assurance measurements which demonstrate the accuracy and precision of the method. It will be shown that the method can be used with EPA Superfund Contract Lab Program (CLP) type digestates and has great potential for producing reliable data for As, Sb, and Se in waste samples.
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.
Methods for the Analysis of Organometallic Compounds in Wastes
Authors: Olson GJ , Brinckman FE , Blair WR
Published: February 2009

Organometallic compounds occur in the environment as a result of anthropogenic and biogenic processes. Since organometals are often much more toxic than the corresponding inorganic forms of metals, it is important to be able to speciate the forms of metals in environmental samples at ultratrace levels. Chemical speciation methods, based on the use of chromatographic separations followed by element-selective detection, have been developed in our laboratories and elsewhere. These methods, described in part in this paper, are helping us to measure organometal species at their action levels (down to parts-per-trillion levels) in environmental matrices, leading to a better understanding of environmental occurrence, fate, effects, and transformation. New methods for nondestructive analysis of metal species on surfaces are under development.
Fatigue Crack Closure: Observations and Technical Significance
Authors: Schijve J
Published: February 2009

The meaning of crack closure for fatigue crack growth resistance is discussed under different headings: (1) mechanistic aspects of crack closure—essential differences between microcracks and macrocracks, microstructural influences; (2) direct methods and indirect methods to measure crack closure; (3) numerical aspects of crack closure relations for constant-amplitude loading; and (4) crack closure and variable-amplitude loading. The paper summarizes the present state of the art. Attention is paid to microstructural aspects, changing crack growth mechanisms under threshold conditions and 3-dimensional aspects including plane strain/plane stress problems.
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.
Crack-Closure Effects on the Growth of Small Surface Cracks in Titanium-Aluminum Alloys
Authors: Larsen JM , Williams JC , Thompson AW
Published: February 2009

Among other factors, the reported failure of linear elastic fracture mechanics to correlate the growth rates of large and very small fatigue cracks has been attributed to microstructural and crack closure effects. These two factors have been examined in experiments on three titanium-rich Ti-Al alloys, which display significant differences in plastic slip character ranging from homogeneous wavy slip to extremely heterogeneous planar slip. The variation in slip character has a dramatic effect on the level of roughness induced crack closure, which in turn, strongly influences the growth rate behavior of large fatigue cracks. In the present project the behavior of small fatigue surface cracks in these materials was investigated using two specialized experimental techniques. A computer-controlled photomicroscopic system was employed to monitor surface crack length directly, and an automated laser interferometric technique was used independently to determine crack length and to measure the development of crack closure. Although slip character has a strong influence on the propagation of large cracks, the present findings indicate that there is a minimal effect of slip character on the growth of small fatigue cracks. Direct crack opening displacement measurements indicate that this is largely because of a transient development of crack closure in the small cracks. For the materials tested, the crack depth required to fully develop crack closure ranged from 5 to 13 times the mean distance between grain boundaries. Above this crack size, data from small surface cracks and large cracks in C(T) specimens were well consolidated by the linear-elastic parameter ΔK.
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.
Comparison of Methods for Measuring Fatigue Crack Closure in a Thick Specimen
Authors: Ray SK , Grandt AF
Published: February 2009

The objective of this paper is to compare fatigue crack closure loads obtained by various crack opening displacement methods. Crack closure loads are obtained by three different techniques: optical interferometry, backface strain measurements, and crack mouth opening displacement (CMOD) gage measurements. Optical interferometry gives complete through-the-thickness variation of crack closure, while backface strain and CMOD measurements provide an average (bulk) crack opening load for the entire specimen thickness. The present paper focuses on comparing the bulk specimen measurements of crack opening load with point measurements obtained at various points along the crack front from the interferometry method. It was observed that the closure loads obtained from backface strain measurements agree well with the CMOD closure values, although the interferometric crack opening loads are higher than either compliance techniques.
A Statistical Approach to Crack Closure Determination
Authors: Roberson LJ , Kirk MT
Published: February 2009

A statistical procedure was employed to determine opening loads from load versus crack opening displacement data records taken during fatigue crack growth rate testing of a high strength steel weldment. The slope of the upper linear portion of the load-deflection curve served as a control value, which was compared with slopes calculated over successive intervals of the curve. Opening loads were defined using a statistical test to consistently determine deviation from linearity on the upper portion of the load deflection curve. These loads depended on the size of intervals taken and the number of data pairs in each interval. Data records of various densities, degrees of scatter, and degrees of curvature were analyzed to evaluate the procedure's ability to determine consistent opening loads. By systematically accounting for test dependent data scatter, or “noise,” a consistent definition of opening load was achieved.
Determination of Crack Opening Load by Use of Threshold Behavior
Authors: Döker H , Bachmann V
Published: February 2009

The effective stress intensity factor range ΔKeff of a Ti-6Al-4V alloy has been determined by using the threshold behavior of this material. The ΔKeff values thus determined are in complete agreement with the materials constant amplitude crack growth behavior. ΔKeff values determined from the opening load obtained by crack opening displacement (COD) and by back-face strain (BFS) are not consistent with the ΔKeff values obtained via threshold and cannot explain certain load sequence effects. This leads to the conclusion that COD and BFS measurements are unsuitable for the determination of ΔKeff, at least for this titanium alloy.