bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring the Integrity of Totally Encapsulating Chemical Protective Suits
Authors: Johnson JS , Stull JO
Published: February 2009

The Lawrence Livermore National Laboratory's (LLNL) Hazards Control Department has recognized for some time that totally encapsulating chemical protective (TECP) suits must be tested to assure that they function properly with a high degree of reliability. Two general types of tests are necessary to properly evaluate a TECP suit: design qualification tests and field use tests. To develop these tests for the evaluation of TECP suit performance, LLNL is participating in a jointly funded project with the U.S. Coast Guard, the U.S. Occupational Safety and Health Administration, and the U.S. Fire Administration. Four tests have been developed to measure TECP suit performance: a quantitative test, a worst-case chemical exposure test, a pressure leakage test, and a chemical leak rate test.

A quantitative TECP suit test method using Freon 12 gas and an aerosol, polyethylene glycol molecular weight 400 (PEG 400), to measure the leakage of both test agents into the suit is being developed. This leak rate is expressed as a “protection factor” that is calculated by dividing the outside test agent concentration by the suit interior test agent concentration. A worst-case chemical exposure test has been demonstrated using the U.S. Coast Guard's Teflon-coated Nomex TECP suit in a hydrogen fluoride gas cloud.

Two types of field use tests have also been developed. The TECP pressure test measures the suit leak rate by inflating the suit to a prescribed pressure and monitoring pressure drop in the suit over time, ASTM Standard Practice for Pressure Testing of Gas Tight Totally Encapsulating Chemical Protective Suits (F 1052-87). The proposed chemical leak rate test consists of generating a known ammonia concentration in a test room, wearing the TECP suit into the room, and doing a series of prescribed light exercises. The interior of the suit is monitored for ammonia after the test subject exists the test room, and the protection factor is calculated in the same manner as described earlier in the Freon 12 test procedure.

By employing the four TECP suit tests in the various stages of suit development and field use, a high degree of safety can be assured.
Evaluation of the Performance of One-Way Valves Used in Chemical Protective Suits
Authors: Swearengen PM , Johnson JS , Sackett CR , Stull JO
Published: February 2009

We developed a method to test totally encapsulating chemical protective (TECP) suit vent valves. The work reported here is a preliminary investigation of four small valves. Two of the valves were low-pressure vent valves from suits and two others were respirator valves. The latter were a pressure demand type and a standard flapper valve. For testing purposes, a single valve was mounted within a plastic plate. The plate was then installed between two halves of a testing box and consequently served to divide the box into two compartments. Each valve functioned as the only conduit between the separate compartments. We observed that methane gas penetrated through one of the TECP vent valves and the pressure demand respirator valve when each was in a “closed” position (with zero differential pressure across the valve). We also observed that when air pressure on the “inside” of each valve was increased, the leak rate decreased. This effect occurred under both static and dynamic conditions. The dynamic conditions were achieved with the use of a variable rate breathing machine. Further research is needed to allow more general conclusions to be made.
Development and Testing of Protective Clothing for Lawn-Care Specialists
Authors: Slocum AC , Nolan RJ , Shern LC , Gay SL , Turgeon AJ
Published: February 2009

The objective of this study was to develop protective clothing for lawn-care specialists and to test the effectiveness of the clothing as a barrier to pesticides in comparison with the regular company uniform. Six volunteers, three wearing the experimental protective clothing and three the company uniform, sprayed a field dilution of Dursban 4E while carrying out regular work activities on each of two test days. Volunteers served as their own controls, wearing a different clothing treatment on the two days. Protective clothing consisted of a cotton/polyester, long-sleeve knit shirt with woven yoke overlay and work pants lined with a microporous film laminate in the lower legs and abdominal area. Urinary excretion of the metabolite 3,5,6-TCP, standardized on the basis of creatinine concentration, measured pesticide absorption. Data indicated that the protective clothing significantly reduced the amount of pesticide absorbed relative to the regular uniform.
Factors Influencing Design of Protective Clothing for Pesticide Application
Authors: Fraser AJ , Keeble VB
Published: February 2009

Use of protective clothing while applying pesticides to crops is considered a deterrent to dermal exposure. A design for a protective garment and hood for fruit orchard workers was developed at Utah State University. The prototype was manufactured in Gore-Tex, Saranex-laminated Tyvek, and an experimental composite structure. Workers wore all garments and personal work clothing in a field setting. After wearing the prototype on the job for an average 2-h period, fruit orchard workers evaluated the garment for functional designing qualities, sizing, and styling features. The protective suit was favorably rated. The hood design was found to be inadequate. Specifications for the garment needed length adjustment in the sleeve area and additional ease through shoulders. The hood design needs complete revision. The prototype evaluation suggested that desirable styling features and appropriate sizing characteristics definitely increase wearability potential of protective garments.
Guthion Penetration of Clothing Materials During Mixing and Spraying in Orchards
Authors: Keeble VB , Ryan Dupont R , Doucette WJ , Norton M
Published: February 2009

Data are presented from a field investigation of the extent of penetration of Guthion wettable powder (azinphos-methyl) through work clothing (regular and Tyvek spray suits) and three protective garments (Saranex-laminated Tyvek, Gore-Tex, and an experimental composite structure) during the typical mixing and spraying activities of fruit orchardists in central and northern Utah. Exterior and interior azinphos-methyl levels were collected using α-cellulose pads and were used by quantify exterior exposure patterns and percent protection afforded by each garment type. No relationship between inside azinphos-methyl pad levels and outside azinphos-methyl loading (µg/cm2 of patch), ambient temperature, relative humidity, or wind speed was evident for any of the garments tested based on results of correlation analyses.
Exposure Measurements Concerning Protective Clothing in Agriculture
Authors: Batel W , Hinz J
Published: February 2009

Risk assessments associated with the handling and spraying of pesticides are based on both exposure and toxicological data. The quality of this assessment depends, to a large degree, on the circumstances at the time of worker exposure. Therefore, in addition to field exposure measurements, it is important to develop both predictive methods for estimating worker exposures and for establishing the causal relationships between exposure and adverse health effects. Using data derived from both approaches, it is possible to estimate the degree of risk associated with various pesticide application scenarios and make recommendations for appropriate protective clothing. Actual field measurements can be used to test the suitability and effectiveness of protective clothing requirements. In this report, we describe the use of two protective clothing indicators: the penetration rate and water vapor permeability with respect to thermal comfort.
Engineering Controls and Protective Clothing in the Reduction of Pesticide Exposure to Tractor Drivers
Authors: Lunchick C , Nielsen AP , Reinert JC
Published: February 2009

Reduction of exposure received during occupational use of pesticides is one of the principal strategies available to the Environmental Protection Agency in reducing risk. The Exposure Assessment Branch of the Office of Pesticide Programs has evaluated applicator exposure studies in which pesticides were applied by ground boom or airblast spray methods. The dermal exposure to the applicator in an enclosed tractor cab during ground boom application was estimated to be one-sixth the exposure to the applicator conducting similar operations with an open tractor cab. During airblast applications, exposure to applicators in enclosed vehicles was more than thirtyfold less than to airblast applicators in open vehicles. At present, the major emphasis in reducing applicator exposure to pesticides has been to require the use of protective clothing. Surveys of applicators indicate that they frequently do not use the required protective equipment. The use of engineering controls such as enclosed vehicles is another risk-reduction strategy available to the Agency. This paper reviews the effects on exposure by tractor-cab design and the advantages and disadvantages of protective clothing and engineering controls in reducing total pesticide applicator exposure.
Pattern of Dermal Deposition Resulting from Mixing/Loading and Ground Application of 2,4-D Dimethylamine Salt
Authors: Grover R , Cessna AJ , Muir NI , Riedel D , Franklin CA
Published: February 2009

Regional dermal deposition of the dimethylamine salt of 2,4-(dichlorophenoxy) acetic acid (2,4-D DMA) on farmers when handling, mixing, and spraying the herbicide was determined following 30 separate exposures. Before each spraying operation, the farmers were issued a standardized set of laundered cotton clothing that covered most of the body with two layers of clothing. Dermal samplers were placed under the clothing at nine locations and also on the neck and head regions. Two additional dermal samplers, attached over the clothing in the chest and elbow regions, provided direct comparison of outside/inside deposits.

Three distinct levels of dermal deposits could be clearly ascertained. The lowest median 2,4-D (acid equivalent; a.e.) deposit densities occurred under two layers of cotton clothing. These densities were quite uniform and indicated a greatly reduced but nevertheless general permeation of the herbicide through two layers of protective clothing. Somewhat higher median deposit densities were found on exposed body regions less likely to be contaminated during the mixing process, such as the head, neck, and outside elbow regions. The highest median deposit densities occurred on regions of the body most likely to be contaminated during the mixing process, that is, the wrist and chest regions. In the two body regions (chest and left elbow) where direct comparison could be made between deposits outside and beneath the clothing, a significant protective effect was observed, with the median deposit density suggesting a three- to eight-fold protective effect. It may, however, be pointed out that the overall body deposits, minus the hand regions, were only 10 to 20% of the total body deposits and thus, when protective garments equivalent to those used in this study are worn, hand protection must remain a major concern when spraying herbicides with ground-rigs.
Use of Fluorescent Tracers and Video Imaging to Evaluate Chemical Protective Clothing During Pesticide Applications
Authors: Fenske RA
Published: February 2009

The addition of fluorescent tracers to agricultural spraying systems allows the direct evaluation of protective clothing under actual field conditions. Deposition of the tracer beneath clothing is quantified by means of a video imaging system. Workers are illuminated under long-wave ultraviolet light following exposure, and the fluorescence on the skin is measured. This exposure assessment technique was tested with 25 workers conducting mixing and high-volume airblast application procedures with the organophosphate pesticide malathion in citrus groves. Three types of protective clothing were compared: cotton/polyester workshirts, cotton/polyester coveralls, and nonwoven coveralls (untreated Tyvek). All workers had measurable hand exposure, despite the use of neoprene gloves. Hand exposure to mixers was more than twice that of applicators. Substantial deposition of tracer occurred beneath clothing. The applicator group wearing workshirts was more highly exposed than either of the coverall groups (Analysis of Variance, p < 0.05). Exposure between the two coverall groups did not differ significantly for either mixers or applicators. The heaviest depositions for the coverall groups occurred near the openings of the garments (collar and sleeves), suggesting that studies of penetration through fabric do not provide a complete evaluation of potential exposure under field conditions. This study demonstrates that fluorescent tracers and video imaging can be used to provide a quantitative index of protective clothing field performance.
Comparison of a Thermal Test Battery Analysis and Field Assessments of Thermal Comfort of Protective Apparel for Pesticide Application
Authors: Hassenboehler CB , Nigg HN , DeJonge JO
Published: February 2009

Protective apparel fabrics designed to reduce dermal exposure during pesticide spraying procedures were evaluated relative to thermal comfort under sweating/high heat stress conditions. Preliminary results from field tests conducted in Florida were compared to thermal comfort predictions inferred from a battery of thermal tests on the fabrics.

The thermal battery consisted of thermal transmittance with simultaneous moisture transport, a profile of air permeability over a range of differential pressure, and a radiant temperature parameter introduced as the clothing radiant temperature. The performance of a fabric in each specific test was graded on a 10-point scale system. Higher points were awarded according to the fabrics' ability to relieve or lower heat stress associated with thermal discomfort. Individual and cumulative thermal comfort scores were compared to field test results. The effect of heat, moisture, and air transport on thermal comfort as inferred from the thermal test battery data provides a reasonable indicator of actual field study thermal comfort testing.
Distribution of Malathion on Gore-Tex Fabric Before and After Sunlight Exposure and Laundering as Determined by Electron Microscopy
Authors: Branson DH , Rajadhyaksha S
Published: February 2009

The distribution of malathion residue on Gore-Tex fabric was examined using electron microscopy. The percent malathion retained in laundered and unlaundered fabric specimens and in the individual Gore-Tex layers was determined with gas chromatography. Concentrations of malathion were found on the surface of nylon fibers and in the interstices between fibers in both the face and the backing fabric layers as well as in the membrane of both the unlaundered and laundered samples. These findings were verified and the percent residue retained by fabric layer was quantified. Thus, the Gore-Tex fabric tested was not an effective barrier to the undiluted malathion solution. Also, the distribution of the pesticide changed after laundering. The Gore membrane retained the highest proportion of pesticide of the three layers, suggesting the ineffectiveness of an aqueous laundry system for removal under these conditions.
Strategies for Laundering Protective Apparel Fabric Sequentially Contaminated with Methyl Parathion
Authors: Goodman CJ , Laughlin JM , Gold RE
Published: February 2009

Fabrics were contaminated daily with methyl parathion for up to five days, laundered, and residues before and after laundering determined. Two fabrics (100% cotton and 50/50% cotton/polyester) of two finishes (unfinished and fluorocarbon soil-repellent) were studied with one-half the specimens laundered daily following contamination and the other half laundered only on the last day following daily contamination.

Gas chromatographic analysis showed that methyl parathion soiling was additive over the five-day period at each additional contamination. The soil-repellent finish was effective through two launderings in limiting sorption of pesticide. In specimens laundered daily, post-laundering residues were similar across each of the five days. Differences in laundered fabric attributable to the fiber content of the specimen and to the functional finish were observed.

Soiling increased across the five days with no laundering such that the washing process was not as effective in removal of the methyl parathion residues. When specimens were contaminated repeatedly and lundered only once, the analysis of wash water showed sizable contaminate; however, when the specimens were laundered daily, proportionately less contamination was evident.
Effect of Temperature and Humidity on Laboratory Pesticide Penetration Studies
Authors: Anastasakis MT , Leonas KK , Dimit C , Brothers J , DeJonge JO
Published: February 2009

The purpose of this study was to evaluate the effect of three conditions of temperature and humidity on pesticide penetration through the fabric. Two fabrics were used, a 100% cotton and a 50/50 cotton/polyester. The three conditions used were 29°C (85°F) with 75% relative humidity (RH), 22°C (72°F) with 65% RH, and 18°C (65°F) with 55% RH. The application of Dicofol pesticide was completed using an enclosed spray chamber that simulated actual field conditions encountered during air blast spraying. Fabric type had a greater influence on pesticide penetration than atmospheric conditions. Consistent standard laboratory conditions of 21.1°C (70°F) with 65% RH are recommended for use in future laboratory penetration tests.
Chlorpyrifos Residues in Protective Apparel Fabrics Following Commercial or Consumer Refurbishment
Authors: Laughlin JM , Lamplot J , Gold RE
Published: February 2009

This study examined the effectiveness of home laundering with a fabric softener and commercial laundering with starch on the removal of pesticide residues from fabric specimens. A 0.2-mL aliquot of chlorpyrifos (0.5% AI, emulsifiable concentrate) was pipetted onto fabric specimens cut from two fabrics (100% cotton and 50% cotton/50% polyester) with two finishes (unfinished or fluorocarbon soil-repellent finished). Laundering treatments included commercial laundering with and without starch, and home laundering with and without fabric softener. The most significant factor in removal by laundering and in contamination level before laundering was the soil-repellent (SR) finish. The soil-repellent finish inhibited absorption of chemical on the controls; however, any treatment that involved laundering diminished the effectiveness of the SR finish. Pesticide removal was similar between the unfinished specimens and the SR finished specimens.

Additional aqueous solutions in commercial laundering did not result in greater residue removal. A single application of starch or fabric softener did not affect pesticide absorption. Starch and fabric softener were not shown to be effective laundry auxilaries in lowering pesticide residues and did not affect after-laundering residue levels when specimens had been laundered with these auxiliaries prior to contamination.
Test Method Development and Evaluation of Protective Clothing Items Used in Agricultural Pesticide Operations
Authors: Ehntholt DJ , Almeida RF , Beltis KJ , Cerundolo DL , Schwope AD , Whelan RH , Royer MD , Nielsen AP
Published: February 2009

Protective clothing is the principal defense of millions of farm workers and pesticide mixers/applicators against skin contamination by pesticides. Unfortunately, few data are available in the public domain to permit the identification of appropriate protective items for specific categories and types of pesticides and pesticide formulations. The U.S. Environmental Protection Agency (EPA) has therefore sponsored an effort to produce, assemble, and critically evaluate data on the effectiveness of protective clothing for agricultural uses. This paper describes (1) efforts to develop a rapid screening method for determining the compatibility of various glove materials with selected pesticides and (2) comparative analyses of collection media for use with the ASTM Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids and Gases (F 739-85) permeation cell in tests of low-volatility, low-water-solubility active ingredients in pesticide formulations.

Two methods for the rapid screening of protective glove-pesticide formulation compatibilities were tested. Results obtained with a draft ASTM Test Method for Evaluating Protective Clothing Materials for Resistance to Degradation by Liquid Chemicals suggest that inappropriate formulation-glove combinations may be identified by their excessive weight increase after 1-h exposure.

Permeation testing to determine breakthrough times and measure the permeation of formulation components using the ASTM F 739-85 cell and selected gloves and pesticide formulations is a major focus of this program. However, the collection medium to be used in this test when evaluating low-volatility, low-water-solubility pesticides poses a particular program. Various media (water, aqueous surfactant solutions, aqueous alcohol solutions, and solid phase collection materials) were tested using actual pesticide formulations spiked with 14C-labeled active ingredients. A solid silicone rubber material was identified as the most efficient material for collection of parathion and ethion. It has now been used with several protective glove materials and two concentrated pesticide formulations.
Quantitation of Pesticides on Apparel Fabrics
Authors: Fleeker JR , Nelson CN , Braaten AW , Fleeker JB
Published: February 2009

The efficiency of common organic solvents in extracting carbon-14-labeled carbaryl, dicamba, chlorothalonil, and glyphosate from cotton twill was examined. The degree of extractions was influenced by pesticide formulation, pesticide polarity, and solvent polarity. In most but not all instances, higher solvent polarity resulted in greater pesticide extraction. The data have implications in extraction methods selected for quantitation of pesticide residue on fabrics following various refurbishing techniques.
Pesticide Applicator Exposure Monitoring: EPA Guidelines
Authors: Lunchick C , Nielsen AP , Reinert JC , Mazzetta DM
Published: February 2009

The Environmental Protection Agency's Office of Pesticide Programs has published final guidelines for monitoring occupational pesticide exposure. This paper describes various aspects of these guidelines. The advantages and disadvantages of quantifying exposure both by passive dosimetry and biological monitoring are discussed. Requirements for monitoring dermal exposure when protective clothing is worn are described. When field exposure monitoring studies must be carried out and the number of individuals that must be monitored in each study are also specified.
Progress in the Development of a Generic Data Base for Mixer/Loader-Applicator Exposures
Authors: Eberhart DC , Day EW , Knarr RD , Zimmerman DM , Nielsen AP , Reinert JC , Muir NI
Published: February 2009

In recent years, occupational exposure to pesticides by users of these materials has received increasing emphasis from manufacturers, users, and regulatory agencies. To quantitate exposures, either a field study is performed, or data from a study of a similar product are used as a surrogate on a “worst-case” basis. In 1984, a new concept for estimation of occupational exposure to pesticides was presented at the 187th National Meeting of the American Chemical Society in St. Louis. This proposal called for the creation of a database including all the available mixer/loader-applicator data, submitted in generic form without identifying the product or producer. The data would be compiled according to formulation and application technique, and made available to the public. Since 1984, a joint task force of the National Agricultural Chemicals Association, the U.S. Environmental Protection Agency, and Health and Welfare Canada has worked to create the database, which is now accepting data for compilation. This paper reports progress to date on the database.
Field Evaluation of Protective Clothing: Experimental Designs
Authors: Nigg HN , Stamper JH
Published: February 2009

Field evaluation of the protection afforded pesticide workers by apparel lis an emerging research area. The design of experiments is critical for obtaining unequivocal data upon which to base recommendations.

The simplest design is a penetration study using collection devices inside and outside the clothing. The residues on inside devices are compared with the residues on outside devices to calculate “protection.” The residue proportion between inside and outside devices may be as large as 1:99. Although proportions this large are helpful for establishing statistical differences, this design still presents certain problems for the analyst.

A second design utilizes urine only. A 24-h urine specimen is collected. The worker wears the garment for one week and removes it the next. Changes in the concentration of residues in urine allow calculation of protection. This design may be flawed by extraneous exposure, uncertainties about urinary excretion kinetics, or nonurinary excretion routes.

A third design combines the first two, but unfortunately a new set of experimental considerations then emerges.

This manuscript discusses the statistical, chemical, metabolic, and human problems inherent in the three designs, with special reference to the experimental goal of each design.
Relief of Residual Stresses in a High-Strength Aluminum Alloy by Cold Working
Authors: Altschuler Y , Kaatz T , Cina B
Published: February 2009

A systematic study was performed on the effectiveness of plastic deformation in tension and compression relief of residual stresses derived from the rapid quenching of 7075 aluminum. Maximum stress relief was observed after about 1.4% deformation in tension and 1 % deformation in compression. Complete stress relief could not be obtained from either mode of deformation. Stress relief was found to be more effective after deformation in tension than in compression. Significant differences in types and levels of residual stresses were found in specimens deformed seemingly uniform in compression when measured on a free surface, or on one in contact with the platen applying the compressive force. The effect of artificial aging as a supplement to mechanical stress relief also was investigated. The practical implications of the results, particularly with respect to forgings, are discussed. Recommendations are made for further work.
Measurements of the Reduction Due to Proof Loads of Residual Stresses in Simulated Pressure Vessel Welds
Authors: Leggatt RH , Davey TG
Published: February 2009

An investigation of the effects of proof loading on residual stresses in test panels simulating welds in ammonia storage spheres was performed. The two test panels contained welds with different degrees of misalignment and distortion. Measurements were made of the surface residual stresses before and after loading to about two thirds yield and of the strain changes during loading. Previous research has suggested that the residual stress after proof loading is a function of material yield strength and applied proof stress only. In the present project, it was found that the relaxation of residual stresses transverse to the weld was sensitive to the local geometry. However, a simple method for including the effects of residual stresses in defect assessments is proposed.
Vibratory Stress Relief of Welded Parts
Authors: Bouhelier C , Barbarin P , Deville JP , Miege B
Published: February 2009

What is the efficiency of residual stress relieving by mechanical vibration? In this paper, studies were carried out on two primary welded reducer gear boxes weighing 1200 kg each, which were thermally (A box) and mechanically (B box) stress relieved. X-ray stress measurements were made in both cases before and after relieving. Dimensional measurements were made on the B box. During the mechanical treatment the dynamic behavior of the box was followed by acceleration measurements and extensometric testings, in order to estimate the magnitude of the vibration-induced stresses and to detect the eventual presence of a new permanent strain. In the case of thermal relieving, the reduction of residual stresses is about 70 to 100 %. In the case of mechanical relieving, the reduction is between 45 to 100 % for tensile stresses, whereas it is only 0 to 45 % for compressive stresses. Some tests were performed on welded parts of a pump unit component, and the results are similar to the preceding.
Proposed Investigation of Process for Reducing Residual Welding Stresses and Distortion by Vibration (Abstract Only)
Authors: Graham Wylde J
Published: February 2009

As a result of differential contractions that occur during cooling after welding, high tensile residual stresses are formed in welded joints. These residual stresses can constitute major problems both during fabrication and once a structure enters service. During fabrication they can cause large distortions that can be a major obstacle to assembly and, most significantly, to maintaining tolerances in components which must be finish machined. In addition, residual stresses can produce cracking in weldments often necessitating major networking. Once a structure enters service residual stresses increses the risk of fracture, can contribute to the propagation of fatigue cracks, and increase the risk of stress corrosion cracking in susceptible combinations of material and environment. Thus, the presence of residual stresses has been cited as a contributory in many major industrial failures.
Prediction of Residual Stress Relaxation During Fatigue
Authors: Lu J , Flavenot JF , Turbat A
Published: February 2009

This paper presents a model for the prediction of the residual stress distribution during and after fatigue. Finite element software is used for incorporating cyclic plasticity into the calculations. A simplified inelastic analysis was applied. Its essential feature consists of the introduction of a group of internal parameters that characterize local inelastic mechanisms and a group of transformed internal parameters that are linearly linked to the previous ones through a symmetrical non-negative matrix. With this approach, the treatment of the local plastic yield conditions can be made easily from simple elastic analysis. This method was applied on two quenched and tempered alloy steels: shot-peened 35NCD16 (nominal 0.32 to 0.39 C, 0.30 to 0.6 Mn, 0.1 to 0.4 Si, 1.0 to 2 Cr, 3.6 to 4.1 Ni, 0.25 to 0.45 Mo) grade steel and ground 42CD4 grade steel (UNS G41420). The influence of different parameters of fatigue testing are studied, including the number of cycles and applied stress. The computed values of relaxed residual stress distributions were compared with experimental results obtained by X-ray diffraction measurements.
Packing to Reduce Electrostatic Discharge Damage and Related Testing
Authors: Murello AF
Published: February 2009

The protection of electronic components from electrostatic discharge (ESD) is a prime concern at RCA. To establish and support an effective antistatic packing program, various materials were tested and testing methods evaluated. This paper presents the data compiled over two years of application of the static decay and triboelectric testing methods. The data demonstrates that a topically coated PVC tube, in a foil-lined sleeve, is a cost-effective, state-of-the-art method of packing semiconductor devices.
Thin Stone Veneers—A Steel/Silicone Diaphragm System
Authors: Loper W , Obermeier T
Published: February 2009

Stone utilization and fabrication has evolved rapidly in recent years. Originally, stone was a massive structural building material. Today, with the use of sophisticated cutting techniques, stone can be a thin veneer cladding for building exteriors. To utilize this thin stone product a number of prefabricated panel systems have appeared including the Cygnus steel/silicone diaphragm system. The Cygnus system utilizes structural silicone to uniformly distribute the exterior dead and dynamic loads over a galvanized steel diaphragm panel. This patented, proprietary manufactured system provides a tough, durable, light-weight exterior skin utilizing stone, tile, aluminum, or glass exterior cladding material.
Exterior Wall Systems Performance and Design Criteria: Should These Vary with Different Types of Cladding Systems—Glass Fiber Reinforced Cement, Stone, Metal, Glass—Panel, Frame, or Veneer?
Authors: Smith GH
Published: February 2009

This paper will discuss the difference between performance criteria and design criteria, how performance criteria can affect selection of material and support system, and how each different material and support system may have different design criteria which must be addressed.

This paper will present an overview of the subject keyed into specific project experiences and is intended to serve as a reminder of topics to be addressed by designer in material and system selection and construction document preparation.
Compositional Analysis of Drugs and Injectable Biological Products by Thermogravimetry
Authors: May JC , Wheeler RM , Del Grosso A
Published: February 2009

Thermogravimetry (TG) is specified in the U.S. Pharmacopeia for the compositional analysis of certain drugs. It is specified for use in determining the percentage of volatile substances in drugs such as vincristine sulfate and vinblastine sulfate. TG reveals interactions between a controlled atmosphere and a drug and between an active substance and excipients. TG is used in the compositional analysis of injectable biological products in various ways. For pneumococcal, Haemophilus b, and meningococcal bulk polysaccharides that are used in vaccine production, TG is used to determine the moisture content (approximately 5 to 25 percent) so that the content of protein, nucleic acid, phosphorus, and other constituents may be accurately determined on a dry weight basis to demonstrate that a sample meets the specifications for the product. TG is also used to determine residual moisture in freeze-dried final container biological products such as Blood Grouping Sera and Antibody to Hepatitis B Surface Antigen. TG is used to confirm or supplement information obtained from Karl Fischer or gravimetric (loss on drying) moisture analysis techniques. TG has been combined with mass spectrometry to verify moisture data for group Y meningococcal poly-saccharide and freeze-dried antibody to hepatitis B surface antigen and to identify an impurity in a Haemophilus b polysaccharide.
Applications of Thermogravimetry/Atmospheric Pressure Chemical Ionization Mass Spectrometry to Compositional Analysis
Authors: Dyszel SM
Published: February 2009

The application of a technique combining thermogravimetry and atmospheric pressure chemical ionization mass spectrometry is shown for selected analytical problems encountered by the Research Division of the U.S. Customs Service. These include the compositional analysis of a fabricated object, the detection of a benzenoid containing compound in a complex matrix, the compositional analysis of styrene-butadiene rubber blends, the differentiation between the natural and chemically modified forms of a natural product, and finally, the determination of country of origin of another natural product. In each of these cases, the combination of the two techniques provided the information necessary to address the analytical problem.
Thermoanalytical Studies on Simple and Mixed Lanthanide Complexes
Authors: Rao VR
Published: February 2009

Thermogravimetry (TG) and differential thermal analyses (DTA) of simple and mixed lanthanide complexes have been studied. These studies gave very interesting results and led to the following conclusions:

(1) The presence of water molecules either in a lattice or coordinated was indicated in a thermal study of (a) neodymium barbiturate simple complexes and its oxine mixed complexes, (b) dysprosium dimethyl-glyoximate and diacetylmonoximate, and (c) samarium phenanthroline, N-phenylurea, and N-N' diphenylurea simple complexes.

(2) One could postulate different routes of decomposition. However, on close examination of the results of TG and DTA, only one route of decomposition is possible. Examples of such cases are (a) gadolinium-dimethyl-glyoxime-diphenylthiourea mixed complex and (b) gadolinium thiourea-urea-mixed complex.

(3) Based on a study of thermal analysis, the possible routes of decomposition and formation of intermediates can be postulated. The intermediates formed do sometimes have a definite composition. They can be isolated and their composition established. Sometimes, such intermediates cannot be synthesized by normal methods. Hence, the study of thermal analyses leads to the synthesis of certain complexes that, under normal conditions, are difficult to synthesize. Such an example is the formation of the gadolinium-thiourea simple complex in a thermal study of the mixed complex of Gadolinium-dimethyl-glyoxime-thiourea.

(4) The study of thermal analyses of several simple and mixed lanthanide complexes indicated that certain ligands such as dimethyl-glyoxime, diacetylmonoxime, and thiourea exhibit the same thermal stability in both simple and mixed completes. The thermal stability of the above ligands in simple and mixed lanthanide complexes is discussed.
Thermogravimetry as a Diagnostic Aid to Bench Scale Kentucky Oil Shale Retorting Studies
Authors: Harris MB , Rubel AM , Carter SD , Davis E
Published: February 2009

Compositional analysis by thermogravimetry (TG) was used to determine the moisture, volatile matter (VM), carbon dioxide from carbonate minerals, fixed carbon (FC), and ash from Kentucky oil shale. This analysis provided a rapid method of screening Kentucky oil shale for potential oil yields. The volatile matter released up to 550°C correlated with oil yield as determined by Fischer assay (R2 = 0.918) for 29 samples from a core drilled in Madison County, KY.

Determination of volatile matter and fixed carbon by TG in spent shale samples from both fixed and fluid bed bench scale retorts proved useful in assessing the effects of varying retorting conditions on the chemistry of Kentucky oil shale pyrolysis. Oil yields obtained under a wide range of retorting conditions were inversely related to the ratio of fixed carbon in the spent shale to the fixed carbon in the raw shale (FC ratio). This ratio provided evidence of the magnitude of secondary reactions in oil yield losses during retorting as a function of processing conditions. Release of volatile matter from the shale during retorting depended on the maximum temperature experienced by the shale and the type of reactor used. The FC ratio and the percentage of volatile matter removed from the shale were used to perform retorting diagnostics for the Kentucky Energy Cabinet Laboratory's (KECL) fluid bed oil shale miniplant.
Thermogravimetry as a Tool for Determining Combustion Efficiency and Calcium Utilization of a Fluidized Bed Combustion Furnace
Authors: Culmo RF , Fyans RL
Published: February 2009

Coal, the most abundant natural fossil fuel, is projected to be a major source of energy well into the next century. Because of this, much experimentation an development has been directed toward using this fossil fuel effectively. Coal's disadvantage is that much of it is high in sulfur. Consequently, its use in fossil fuel power plants poses a major emissions problem.

This work was performed to learn how thermogravimetry can be used to determine the combustion and sulfur scrubbing efficiency of a fluidized bed combustion furnace used in these power plants.

In this furnace design, a fuel mixture of coal and limestone is used. The limestone is added to remove the sulfur through an in situ scrubbing technique. The fluidized bed design employs high pressure air to both feed the fuel and provide oxygen for combustion. This method causes the fuel to levitate, essentially simulating a fluid mass. This levitation of the fuel mixture provides for more efficient combustion and also enhances the reaction of the calcium oxide with the sulfur oxides that evolve from the coal. Analysis of both the fly ash and bed ash resulting from the combustion should provide a measure of the effectiveness of sulfur oxide removal and combustion efficiency.

The Perkin-Elmer TGA 7 [1] was employed to analyze these ashes for unburned fuel and unreacted calcium oxide. These analyses were performed using three different atmospheres—nitrogen, oxygen and carbon dioxide. Nitrogen was used to remove water and any calcium carbonate. Oxygen was used to oxidize and thereby determine the amount of any unburned fuel. Carbon dioxide was used to recombine calcium carbonate from any unreacted calcium oxide and thereby determine the calcium oxide content.
Analysis of Flue Gas Scrubber Materials from a Coal-Fired Power Plant by Thermogravimetry
Authors: Dorsey DL , Buecker BJ
Published: February 2009

Accurate analysis of reagent and reaction products during flue gas sulfur dioxide (SO2) removal by wet-limestone scrubbing provides important information on system efficiency and operating conditions. Major process constituents that must be determined are calcium carbonate (CaCO3), coprecipitate hemihydrate [(CaSO3·CaSO4)·½H2O], and gypsum (CaSO4·2H2O). Analysis procedures using existing equipment and instrumentation proved too lengthy and inaccurate. A microcomputer-controlled thermogravimetric analysis system was chosen to improve the analysis procedure and results. The analysis procedure consists of heating a dry sample at a constant rate to 950°C in the analyzer. Each of the three major constituents is distinctly identified, and interferences are minimal. A standard software program determines the weight loss of each transition, and a stoichiometric weight calculation is performed to determine the amount of each constituent. Thermogravimetry (TG) is also useful in the analysis of limestone (CaCO3). Comparisons of TG results with independent laboratory results show excellent agreement. Sample preparation and analysis times have been reduced to half that needed by other methods.
Mineral Insulating Oil Manufacture and Safekeeping
Authors: Lipscomb TG
Published: February 2009

This paper presents a general overview of the methods used to refine conventional mineral insulating oils. The discussion will outline the individual refining processes and the effect each may have on the composition of the oil. Included will be a brief discussion of the Occupational Safety and Health Administration's Hazard Communication Standard, 29 CFR 1910.1200 as it can apply to mineral insulating oil and some suggestions for handling and storage of the oil to reduce contamination and degradation.
Insulating Oil Qualification and Acceptance Tests from a User's Perspective
Authors: Johnson DL
Published: February 2009

To be acceptable, insulating oil must have several specific electrical, chemical, and physical attributes. Tests that demonstrate that the oil does indeed possess the desired characteristics are required. The tests specified by one utility are outlined in the paper with limits listed. Also described in the paper are insulating oil uses on a utility system. An attempt is made to relate oil use to each required test. The relative significance of each test is addressed.
Newly Developed Analytical Techniques for Characterization of Insulating Oils
Authors: Crine J-P
Published: February 2009

A review of newly developed or improved analytical techniques for characterization of insulating oils is made. The emphasis is put on recent techniques, procedures, and applications developed at IREQ in five major areas of oil characterization: thermal aging, electrical properties, particles and metals in oil, gases in oil, and low-temperature applications. It is shown that among other things, the antioxidant content, as measured by HPLC, can be a simple and reliable way to estimate oil oxidation. The influence of particles and metals in oil on a-c breakdown strength are also stressed, and an ultrasonic agitation procedure is proposed to rehomogenize oil samples before electric breakdown measurements. Finally, new trends and future developments, including static electrification and scale model studies, are pointed out.
Static Electrification in Power Transformers
Authors: Crofts DW
Published: February 2009

The subject of static electrification and related transformer failures has gained the attention of the industry in the last decade. To some extent electrification activity occurs with flowing insulating oil passing over insulation items within every transformer. The extent of the electrification determines whether or not this activity is detrimental to the dielectric integrity of the transformer.

Within the paper, failures are described—two of which occurred on the TU Electric system. Several others have occurred in the United States and even more worldwide. Many of the actual failures have not been well documented and statistical information is lacking in the literature.

Electrification activity is enhanced by many variables which are described in the text. Methods of minimizing detrimental activity are discussed and the need for monitoring techniques is stressed.
Collaborative Study of the Toxicity Characteristic Leaching Procedure (TCLP)
Authors: Blackburn WB , Show I , Williams L , Taylor DR , Marsden PJ
Published: February 2009

The United States Environmental Protection Agency has developed a new procedure, the Toxicity Characteristic Leaching Procedure (TCLP), to more effectively simulate the leaching of hazardous materials from waste disposed in an unsecured landfill. The procedure involves (1) an 18-h extraction of a sample with sodium acetate solution and (2) the subsequent analysis of the leachate for metals, pesticides, semivolatile organics, and volatile organic compounds. To validate the method for all but the volatile organic analytes, three waste samples at two different pH levels were sent to 23 different volunteer government and commercial laboratories for extraction and analysis. For validation of the TCLP procedure involving determination of volatile organic compounds, two fortified waste samples were distributed to each participating laboratory. The results and statistical analysis of this collaborative test are presented and discussed. These results indicate that the TCLP can be applied consistently by a diverse group of organizations for the analyses considered in this study.