bluuebunny/crossref_metadata_2025 huggingface dataset:
The General Problems of AE Sensors
Authors: Higo Y , Inaba H
Published: March 2009

The general problems of AE sensors are overviewed. The effects of mounting conditions of sensors on the sensitivity are discussed. then the sensitivity measurement methods are compared. The results of a sensor's sensitivity, obtained by NBS and by the Hatano method show that there is very little difference between them.

The convenient calibration method for sensor sensitivities, especially the “acoustic pressure method” and the “pencil lead fracture method” are discuss ed. The characteristics of lead, specially standard pencil lead from JAEWG which produce very stable reproducible AE signals, was demonstrated. The characteristics of the lead is quite similar to the lead produced in 1975. Then sensor sensitivities were obtained by the standard lead and are compared with the results of the reciprocal method.
Development and Future Aspects in AE Source Characterization
Authors: Enoki M , Kishi T
Published: March 2009

The acoustic emission (AE) source characterization has been developed to understand the dynamic process of microfracture in metals, ceramics and composites. The development of AE source characterization can be summarized firstly. This paper is concerned with the theoretical background of AE source characterization. An infinitesimal deformation in a material can be represented as a moment tensor by the ‘eigenstrain method’ of micromechanics. In this treatment a microcracking can be modeled as a dislocation source with moment tensor components. AE signals can be represented as the convolution integral of the source function due to microcracking, the dynamic Green's function of the media and the transfer function of the measuring system. Secondly, our method of AE source characterization is described. We developed the advanced analysis system to evaluate AE signals quantitatively. Source location of each AE is determined from the signals recorded using six transducers. Each dynamic Green's function of the compact tension specimen concerning each source location is calculated by a finite difference method. The transfer function of the measuring system is calibrated by the breaking pencil lead method. Moment tensor components are determined by the developed deconvolution algorithm. Then the size, fracture mode, orientation and nucleation time of microcracks are obtained from the moment tensor. This analysis system was applied to the fracture toughness tests in various materials. Finally, the future aspects in AE source characterization will be discussed.
A Calibration Source for Acoustic Emission Analysis
Authors: Heiple CR , Carpenter SH , Christiansen SS
Published: March 2009

Acoustic emission produced by the fracture of boron particles in 2219 aluminum during tensile deformation was measured and characterized. The boron particles were introduced into the aluminum using a powder metallurgy approach. The response of an rms voltmeter to individual acoustic emission bursts was found to be proportional to the energy of the burst (integral of the squared signal voltage). The energy released by fracture of the boron particles was estimated from elasticity theory using measured diameters of the individual fractures. The energy of the acoustic emission signals produced by boron particle fracture was found to be proportional to the energy released by the particle fractures. This relation can be used to estimate the energy released by other comparable acoustic emission sources in samples of similar geometry from their acoustic emission signals.
Acousto-Ultrasonics: An Update
Authors: Vary A
Published: March 2009

The acousto-ultrasonic technique was devised to assess diffuse flaw populations and any associated changes of the mechanical properties of composites and composite- like materials. Acousto-ultrasonics has been used to evaluate fiber reinforced composites, adhesive bonds, paper and wood products, cable and rope, and also human bone. The potentials and limitations of the technique are reviewed. Basic methods and quidelines are discussed. The underlying hypothesis for acousto ultrasonic materials evaluation is stated and needs for theory and signal analysis development are indicated.
Theoretical Basis of the Acousto-Ultrasonic Method
Authors: Kiernan MT , Duke JC
Published: March 2009

This paper provides a physical interpretation and theoretical basis for acousto-ultrasonic (AU) results, using through-thickness-transverse-resonance (TTTR), Lamb wave theory, and elasticity. Major emphasis is given to building a model of the AU method. The paper begins with a brief introduction to the AU method and experimental results, physical interpretations, associated theory, and comparisons between theory and AU results. Finally, conclusions are presented identifying the modes of wave propagation influencing the AU measurements.
Acoustic Emission Detection of Crack Presence and Crack Advance During Flight
Authors: McBride SL , Pollard MD , MacPhail JD , Bowman PS , Peters DT
Published: March 2009

Results are presented which show that it is possible to detect crack growth and crack presence in airframe components during flight. To accomplish this, a data acquisition system has been developed specifically for in-flight applications. It is shown that crack advance of less than 1 mm2 was readily detected during flight and the fracture-related acoustic emission signals unambiguously identified.
Detectability of Defects in Reactor Pressure Components by Location and Interpretation of AE-Sources
Authors: Sklarczyk C , Waschkies E
Published: March 2009

In the last years many hydrotests, cyclic fatigue tests and thermal shock tests have been carried out on reactor pressure vessels, which exhibited crack-like defects, with the aim to determine the conditions of detectability of growing and nongrowing cracks by acoustic emission (AE). The AE generated during these experiments has been recorded and analysed. Techniques for evaluation of AE-data have been developed which allowed the separation of AE-events from crack growth and crack surface friction by using the distributions of AE signal parameters, especially the rise time. Crack growth can be detected with high sensitivity at thermal shock and fatigue tests whereas detectability of crack surface friction increases with the amount of compressive stresses between the crack surfaces. At hydrotest only a low level AE is produced by nongrowing cracks due to the lack of compressive stresses.
Acoustic Emission During Tensile Deformation and Fracture in Austenitic Alloys
Authors: Raj B , Jayakumar T
Published: March 2009

The nature of the Acoustic Emission (AE) generated during tensile deformation and fracture of two austenitic alloys i.e., AISI type 316 Stainless Steel (SS) and Nimonic alloy PE-16 are presented and discussed. Effects of second phases on the AE are considered. For 316 SS, the second phases are carbides and inclusions. For PE-16, the second phases are carbides and coherent precipitates i.e., Ni3(Al,Ti). Time and frequency domain analyses have been used to characterise the dislocation behaviour. Correlations of dynamic strain ageing in 316 SS with AE signal are presented. A method to amplify the weak AE signals in 316 SS is highlighted. The studies in PE-16 have shown that AE can be correlated with the type of interactions i.e., whether Orowan looping and/or particle shearing is operating.
Tool Monitoring by Acoustic Emission
Authors: Roget J , Souquet P , Deschamps M , Gsib N
Published: March 2009

Monitoring cutting tools is a strong need in automated un-manned production systems. However tool breakage detection should be separated from tool wear monitoring. The works presented in this paper show that Acoustic Emission (AE) can be used for detecting tool breakage in most conditions and an industrial system is available. Tool wear monitoring is much more complex. As demonstrated by some results in turning and milling, there are a great number of influencing parameters. It appears that AE has also capabilities for tool wear monitoring but no industrial system is presently available. Expert system or intelligent system such as Neural Networks using multiparameter appear to be the best solution for the future.
Acoustic Emission Analysis and Ultrasonic Velocity Imaging in the Study of Rock Failure
Authors: Falls SD , Chow T , Young RP , Hutchins DA
Published: March 2009

Two methods were used to examine the effects of stress changes and microfracture activity during Brazilian disk tests performed on Lac du Bonnet Granite. Acoustic emission analyses examining source locations and source mechanisms led to two main findings. Firstly, the sources were clustered in the regions with the greatest difference between the minimum and maximum principal stresses. Secondly many sources involved some degree of shear motion. This indicates that dilatancy in these rocks may be largely controlled by hybrid shear-tensile microfractures. Ultrasonic tomographic imaging of p-wave speed was the second technique used to study stress induced effects on the samples. The images created have successfully delineated areas of the rock with high stress concentrations.
On the Correlation between Acoustic Emission and Progression of Matrix Splitting in a Unidirectional Graphite/Epoxy Composite
Authors: Ghaffari S , Awerbuch J
Published: March 2009

This paper presents results on monitoring initiation, accumulation, and progression of matrix splitting through acoustic emission in double-edge notched graphite/epoxy coupons. In this specimen geometry matrix splitting is the single dominant mode of damage. Detailed acoustic emission data analysis was performed by which most of the emission generated by the grating among the split fracture surfaces has been identified. Only the acoustic emission generated by the actual growth of matrix splitting has been accounted for. Based on the location distribution histograms of these events the progression of the matrix splits could be tracked. The acoustic emission results were compared with optical observations and excellent correlations were established for all cases studied.
Identification of Fatigue Failure Modes in Carbon Fibre Reinforced Composites with the Energy Discriminating Acoustic Emission Method
Authors: Wevers M , Verpoest I , De Meester P , Aernoudt E
Published: March 2009

Tension-tension fatigue of carbon fibre reinforced composite laminates is characterized by the initiation and growth of specific damage modes. A method was developed to study the AE-signals released from each individual damage source so that the growth of distinct fatigue damage modes could be monitored. The obtained results correlated well with the real damage extent of each individual damage mode. This is an improvement compared to the general information the total number of acoustic emission signals can give on the fatigue degradation of the specimens.
Detection of Impact Damage in Composite Bi-Axial Test Specimens by Use of Thermally-Activated Acoustic Emission
Authors: Whittaker JW , Brosey WD
Published: March 2009

Acoustic emission (AE) produced during thermo-mechanical loading of composite materials is known as thermo-acoustic emission (thermo-AE). When thermally cycled, coupons of various composite materials have been shown to produce quantities of AE which are directly proportional to the damage level. This work demonstrates the applicability of thermo-AE monitoring to an engineering structure.

Impact-damaged bi-axial composite test specimens were thermally cycled and their AE response recorded. An undamaged specimen produced little AE while damaged ones generated widely varying amounts. For damaged specimens, the thermo-AE was found to originate primarily in the damaged regions. Damaged specimens produced AE as a function of increasing and decreasing temperature but the effect was not repeatable. More severely damaged specimens produced copious amounts of AE. It was not possible to determine the source(s) of the emission.
Realistic Expectations for Ground-Water Investigations in the 1990's
Authors: Barcelona MJ , Helfrich JA
Published: March 2009

Significant progress has been made in the design and execution of ground-water investigations for site assessments, the selection of remediation options and long-term monitoring of corrective action operations. Improved reliability and cost-effectiveness in ground-water studies can result from the recognition of both the complexity of the subsurface environment and the need for simple, integrated monitoring approaches. Continued progress in the methodologies of investigation will be enhanced by improvements in conceptualization of subsurface conditions.
The Need for Improved Use of Geologic Data in Ground Water Investigations
Authors: Regan PT , Conte JA , Mitchell MM
Published: March 2009

In our view, the predominant cause of many poor feasibility studies, irrational risk assessments, and failed remediations has been the lack of a sound understanding of the physical characteristics of the aquifer system. Specifically, we refer to the lack of attention to detailed, geologic descriptions of aquifer materials during drilling and the subsequent interpretation of the geologic factors that control the three-dimensional shapes of permeability fields. The environmental industry has generally underutilized the potential benefits of better prediction of aquifer geometries and, therefore, more cost-effective exploitation of geologic conditions. We urge a return to the roots of geologic practice that historically formed the basis for ground water investigations.

In this paper, we propose a retrograde and not entirely innovative method that is based on classical geologic principles. This method depends on the process of developing a detailed evaluation of the physical features of the aquifer skeleton. Hydrogeologic investigations must be based on detailed geologic descriptions and interpretations of complete sections of all boreholes to define stratigraphy and interpret depositional environments. In cases where structural features control ground water flow, detailed measurements of orientations and densities of fabric elements are essential. These interpretive tools provide the physical foundation that will support the remarkable equation-solvers (computer models) which have become so popular. We suggest that cost-effective solutions to problems of contaminant migration in flow systems that may be dominated by advective transport require better prediction of the spatial distribution of permeability fields between widely spaced data points. Better prediction can only be accomplished through refined geologic interpretations based on detailed and reliable field data.
A Proposed Strategy for Assessing Compliance with the RCRA Ground-Water Monitoring Regulations
Authors: Parsons AM , Davis PA
Published: March 2009

To satisfy the Resource Conservation and Recovery Act (RCRA) ground-water monitoring regulations, a hazardous waste management facility must have a ground-water monitoring system consisting of at least one upgradient and three downgradient wells and show that the downgradient wells are capable of immediately detecting a statistically significant amount of contamination at the water table. Because the regulations are subjective, it is often difficult for the owner/operator and the regulator to assess whether a monitor-well network satisfies the regulations. A probabilistic strategy is presented which satisfies the regulations and attempts to minimize subjectivity in evaluating the performance of a monitor-well network.

The proposed strategy is based on a determination of the likely ground-water flow paths through both the unsaturated and saturated zones and ground-water travel times. The approach involves three stages of analysis: 1) optimization of monitor well location, 2) evaluation of the sampling interval, and 3) assessing the monitor-well network performance through time.
The Use of Geophysics in the Detection of Buried Toxic Agents at a U.S. Military Installation
Authors: Allen RP , Seelen MA
Published: March 2009

In 1989 personnel at a U.S. Army base in the southeastern U.S. discovered a 1945 U.S. Army Corps of Engineers Water Distribution System Map identifying an area as “Toxic Agents Buried”. The date of the handwritten inscription is unknown; however, a study of several aerial photos of this area revealed a disturbed area in approximately the same location dating back to the early 1940's. A geophysical study was conducted in this general area in an attempt to pinpoint this location so that the materials could be exhumed and properly disposed of, and to provide a preliminary indication of the distribution of any potential contaminants in shallow soils and shallow ground water.
Geophysical Methods Used to Guide Hydrogeological Investigations at an Umtra Site Near Grand Junction, Colorado
Authors: Wightman WE , Martinek BC , Hammermeister D
Published: March 2009

Surface geophysical surveys played a key role in identifying a suitable hydrogeologic location for a Department of Energy Uranium Mill Tailings Remedial Action (UMTRA) disposal cell near Grand Junction, Colorado. Drilling and excavation work conducted as part of a first phase of site characterization activities had determined that a previously identified 35 hectare (90 acre) disposal cell location was underlain by shallow ground water (6 to 12 meters deep) suitable for domestic use. This shallow ground water was found to be confined to a complex system of alluvial-colluvial filled paleochannels eroded into the upper surface of the underlying Mancos shale bedrock. Geophysical methods were then used to cost-effectively direct a second phase of drilling and excavation activities which delineated an adjacent disposal cell location that was free of shallow ground water. Since this new disposal cell location was within the original designated site area of approximately 240 hectare (600 acres), considerable cost and time savings were realized by this surface geophysics directed field characterization program.
Vadose Zone Characterization Using Field Permeameters and Instrumentation
Authors: Havlena JA , Stephens DB
Published: March 2009

In situ characterization of the hydraulic properties of materials within the vadose zone has become increasingly important over the past several years, and is often the only viable means for testing certain geologic and engineered materials. A variety of field methods exist for the hydraulic characterization of unsaturated materials, including ring-type infiltrometers, air and gas permeameters, air-entry permeameters, borehole permeameters, disc permeameters, sorptivity tubes, infiltration ponds, crust tests, and drainage-type instantaneous profile tests. These methods provide information on a number of hydraulic properties, including soil infiltration rate, permeability to air and soil gas, saturated and unsaturated hydraulic conductivity, sorptivity, mean pore size, and matric flux potential. A wide range of materials may be tested in the field, including sandy alluvium, natural clay and engineered clay liners and barriers, fractured and unfractured rock, and soils with macropores. Each of the available tests is appropriate for different geologic materials and testing requirements. The favorable results of a number of these applications demonstrate that most of these methods are reliable, useful, and economical for characterization of unsaturated materials within the vadose zone.
Techniques for Quantifying the Recharge Rate Through Unsaturated Soils
Authors: Knowlton RG , Parsons AM , Gaither KN
Published: March 2009

Sandia National Laboratories recently designed a sampling and analysis strategy to implement several techniques for quantifying the recharge rate through thick unsaturated, unconsolidated alluvium. Several methods are employed to estimate the recharge rate, including a soil-physics based (i.e., Darcy's law) method, a chloride mass balance technique, a stable-isotope method, bomb-pulse tritium method, and 36Cl techniques. Each of these techniques yields an independent estimate of the recharge rate which may be used to define background percolation rates of conservative solutes, to approximate the upper boundary flux condition for numerical flow and transport modeling of the site, or as calibration criteria in flow and transport modeling.

The soil-physics based approach is an indirect means of estimating the recharge rate through the application of Darcy's law with measured hydraulic characteristic data. The chloride mass balance method assumes piston displacement to estimate the recharge rate utilizing cumulative chloride versus water content data. The stable-isotope method is a tracer technique used to estimate the transport of the isotopic species deuterium (D or 2H) and 18O in the water molecule (H218O and HD16O), which in turn allows for the determination of the recharge rate. The tritium and 36Cl versus depth profiles can be used to estimate soil-water movement rates and soil-water age.
Evaluation of Four Vadose Zone Probes Used for Leak Detection and Monitoring
Authors: Daniel DE , Burton PM , Hwang S-D
Published: March 2009

Gypsum and fiberglass resistance devices, a heat dissipation sensor, and a miniature resistivity probe were evaluated for vadose-zone monitoring. Tests were performed to determine how well the probes would detect changes in the moisture content of soil or in the chemistry of soil water. The probes were imbedded in a clayey soil. The electrical resistivity of gypsum blocks changed with water content over a broad range of water content in calibration cells. Gypsum blocks successfully indicated changes in water content in columns of soil that were wetted. Wet blocks tended to disintegrate when they were repeatedly removed from and inserted into the soil, but no disintegration of blocks left in unsaturated soil for up to 3 months was observed. The electrical resistance of fiberglass devices decreased with increasing water content and salinity of the soil water in calibration cells. The devices did not work well in tests in which the soil was wetted to near saturation — the readings of the fiberglass devices sometimes changed in the opposite sense to changes in the moisture content of the soil. Heat dissipation sensors provided useful information over a relatively wide range in moisture content, yielded stable readings over periods of several months, and did not appear to be particularly vulnerable to degradation in soil. Miniature electrical resistivity probes yielded stable readings over periods of many months. The probes were found to undergo particularly large changes in readings when the soil was wetted with a liquid having a high electrolyte concentration.
Measurement of Organic Vapor Isotherms on Wet Soils and Aquifer Materials
Authors: Farrell J , Reinhard M
Published: March 2009

A technique for measuring organic vapor sorption onto water coated soils and aquifer materials is presented. The method has several advantages over other techniques such as microbalance, extraction, and headspace methods. The solids used are coated with a surface layer of water and are in equilibrium with a gas phase at 100% relative humidity, simulating conditions in the unsaturated zone. Advantages of the method include the ability to measure isotherms over at least 5 orders of magnitude in organic vapor concentration, the ability to measure sorption onto very low sorbing solids, and the ability to allow an indefinite time for equilibrium to be reached.
Quality Assurance in Soil Gas Surveys: False Positive Acetone Identifications at a Codisposal Site
Authors: Heins TR , Kerfoot HB , Miller DJ , Peterson DA
Published: March 2009

This paper points out the importance of quality assurance in soil gas surveys through the implementation of quality control measures. A soil gas survey was undertaken at the Cortese Landfill to assess vapor migration. Soil gas samples were analyzed from 54 locations for 15 volatile organic compounds by gas chromatograph (GC) methods. Quality control measures included GC calibration, replicate, spike and blank samples and analysis of split samples by an off site analytical lab. Acetone was detected at many of the soil gas sample locations at unexplainable concentrations relative to concentrations observed in groundwater. A second GC, equipped with a different column, was used to confirm presence of acetone, but at concentrations lower than those estimated using the first column. This indicated that coeluting compounds may have caused false positive results (misidentifications) in the earlier data. This approach to verification of field analytical data quality assurance proved to be beneficial in preventing costly additional sampling and analysis.
An Effective Monitoring Screen for Fine Sand Aquifers
Authors: Gillespie GA
Published: March 2009

Collecting sediment free samples of low turbidity from monitoring wells installed in fine sand aquifers has been a difficult problem. Wells are often screened in aquifers containing thin lenses of silts and clays having a formation effective size of 0.1 mm (0.004“) or less. Fine sand silty formations are common to the California Bay area where wells, at depths of 6 to 15 meters (20 to 50 feet), are used to monitor landfills. Most of these wells use a conventional design consisting of a 5 cm (2 in.) or 10 cm (4 in.) diameter slotted or wire wrap screen with a filter pack externally placed around the screen to retain the fine sediment. Many of the wells are not useful because they do not provide clear, sediment free samples at reasonable sampling rates. Often, the wells are purged dry before the required purge volumes are removed.

In July, 1988, EMCON Associates installed a series of preassembled, dual walled screens filled with a fine filter pack around the Palo Alto, California landfill to monitor these fine sand aquifers at two different depths. Numerous tests were conducted to determine turbidity, pumping, and recovery rates for three wells that used 0.43 × 0.28 mm (40 × 60 # US Sieve) filter packs. The filter pack passed a #40 Sieve and was retained on a #60 Sieve.

This paper describes well development procedures, methods and measurements, and test results. Based on test results over a simulated four year sampling period, the following results have been achieved. 1. After the wells were stabilized, turbidity readings were consistently less than 20 Nephelometric Turbidity Units (NTU). Sediment was almost nil. 2. Using effective well development techniques, sampling and well recovery rates in fine sand formations can be improved so wells can be sampled in less than one hour. 3. There is no evidence of plugging of the dual walled screens during a simulated four year sampling program.
Using Vibration Strip Transducers for Measuring Water Levels in Monitoring Wells
Authors: Durham GN , Bumala TG
Published: March 2009

A new system is presented that permits unattended measuring of water levels in monitoring wells. The system consists of a sensor connected by an umbilical cord to a data collector all of which can be installed in a monitoring well as small as 51 mm ID. The data collector stores up to 10,000 data points. Sampling frequency, start/stop times, and engineering unit selection are made by the user via portable PC DOS computer connected to the collector through the standard communication port of the computer. The described system provides the means to achieve the precision required in ASTM Standard D4750 “Standard Test Method for Determining Subsurface Liquid Levels in a Borehole or Monitoring Well (Observation Well).”
A Field Investigation of Ground-Water Monitoring Well Purging Techniques
Authors: Maltby V , Unwin JP
Published: March 2009

A field investigation of commonly-used monitoring well purging techniques was conducted under different conditions including type of pump, pump inlet location, and the use of packers. Tracers including deionized water, fluorescent dye, and lithium chloride, were used to define the amount of stagnant water at any given time in the pump discharge. Tests were conducted in shallow 5 cm (2 in) diameter wells. The effects of drawdown were examined.

Tests conducted in the absence of drawdown with the pump inlet in a fixed position at or above the screen showed a highly variable and unpredictable inclusion of stagnant water. The use of packers did not completely prevent the inclusion of stagnant water into the pump inlet. The inclusion of stagnant water into a sample was minimized by purging from some distance above the screen followed by relocation of the pump inlet into the screen for sample collection. In wells where drawdown occurred during purging, stagnant water inclusion was minimized by reduced pumping rates to allow for sample collection during periods of well recharge. Real time monitoring of indicator parameters such as pH, temperature and specific conductance was not generally successful in indicating when purging was complete.
Deployment and Purging for In Situ Sensors in Monitoring Wells
Authors: Schalla R
Published: March 2009

Ongoing development of in situ sensing systems will enable accurate, rapid measurement of many chemical and physical parameters at monitoring wells before the year 2000. The potential reduction of sampling and analysis costs, which are often a major portion of costs for monitoring at CERCLA and RCRA facilities, is the primary reason for the emphasis toward lower-cost in situ methods for obtaining ground-water quality data. The costs are lowered by reducing field labor, reducing or eliminating purge-water-disposal costs, and reducing the number of laboratory analyses. Relatively little has been done either to adapt new in situ technologies to the configuration of existing monitoring wells or to make deployment adaptations for minimizing purge water. Proper deployment of in situ sensor systems in monitoring wells will require an understanding of the monitoring well design with respect to the stratigraphy, lithology, hydraulics, size and configuration of in situ chemical sensor system(s), and purging requirements relative to accuracy of contaminant concentrations.
Measurement of Gas Permeability Through Clay Soils
Authors: Izadi MT , Stephenson RW
Published: March 2009

The engineering profession currently has a standard for measuring the coefficient of water permeability of saturated fine grained soils. However, there has not been any attempt to standardized the procedure of measuring the coefficient of gas permeability of unsaturated fine grained soils. Low permeability fine grained soils are often used in landfills as barriers to retard the movement of hazardous gases.

Petroleum engineers were primarily responsible for development of gas flow theories and measurements. Hence, the available test methods and equipment were developed to suit their demands. On the other hand, the increasing involvement of geotechnical and environmental engineers in design and construction of waste landfills necessitate the development of new techniques suitable to their need.

This investigation developed new apparatus and simple and reliable testing procedures for measuring gas permeability of unsaturated fine grained soils. A series of tests were performed on compacted clay samples to verify the technique.
A Comparison of Field and Laboratory Measurements of Hydraulic Conductivity
Authors: Picornell M , Guerra A
Published: March 2009

The hydraulic conductivity of a soil was measured in the laboratory and in the field. Although each technique used yielded consistent results, the hydraulic conductivity obtained differed over several orders of magnitude. These differences in hydraulic conductivity can only be attributed to macroscopic features that weigh differently depending on the mass of soil affected by the different tests.
Measurement of Hydraulic Conductivity in Clay Using Push-In Piezometers
Authors: Lutenegger AJ , DeGroot DJ
Published: March 2009

The hydraulic performance of push-in standpipe piezometers was evaluated at a site consisting of medium stiff and soft varved clay in western Massachusetts. The results of falling head hydraulic conductivity tests performed in the piezometers were compared with results of tests performed in prebored and sand-packed piezometers and laboratory flexible wall tests performed on undisturbed samples obtained at the site. A comparison of the field and laboratory tests conducted throughout the upper portion of the profile indicates that while tests performed in the prebored piezometers generally gave hydraulic conductivity results higher than laboratory tests, results from tests performed in push-in piezometers were closer to laboratory tests.
Assessing the Usability of Historical Water-Quality Data for Current and Future Applications
Authors: Spreizer GM , Calabrese TJ , Weidner RS
Published: March 2009

Large amounts of laboratory data have been generated as part of environmental investigations, and particularly ground-water investigations conducted during the 1970s and 1980s. These data present a historical water-quality record at a facility by representing, in many cases, the baseline ground-water quality, and changes in water quality due to degradational processes and remedial activities.

Ground-water chemistry data collected during the 1970s and 1980s were often generated using laboratory quality assurance/quality control (QA/QC) procedures considered inadequate by today's standards. In addition, the documentation required to support the quality of the laboratory data may be unavailable. The absence of the supporting QA/QC documentation or the use of different QA/QC procedures than those used today should not be the basis for removal of the data from the facility's ground-water quality database. In a large number of cases, the historical data are “good data.” Historical water-quality data are useful and should be available for use in the design of ground-water monitoring programs, for the selection and design of remedial measures, and to monitor the effectiveness of past and anticipated future remedial activities.

This paper presents a series of techniques that, when used together, can demonstrate the usability of a historical water-quality database where laboratory QA/QC data are unavailable. This paper makes an important assumption that there is a difference between data usability and data validation. The assessment of the usability of a database is performed as a two-part exercise. The first step is to conduct a qualitative pattern recognition procedure and the second is to use more stringent statistical procedures to identify if the data are presenting a consistent description of the ground-water system. This data-usability technique has been successfully applied at a site in California. The results of this case study are also present in this paper.
An Alternative Data Evaluation Technique for Detecting Disposal Site Leakage Events
Authors: Plumb RH
Published: March 2009

A conceptual waste disposal site was compared to a physical model frequently used to demonstrate the properties of entropy. This comparison suggests that dispersion of chemical contaminants due to spontaneous waste disposal site leakage events would be expected to disrupt the ambient chemical homogeneity of an affected aquifer. The resultant changes in aquifer homogeneity can be identified and fingerprinted based on changes in monitoring data variance. Using this alternative data evaluation technique, monitoring data from a RCRA site monitoring program were used to prepare a series of contaminant-specific control charts (monitoring data variance versus time) that identified the occurrence of a leakage event and characterized the contaminants associated with the leakage event.
Ability of 1000 mL Water Leak Test for Medical Gloves to Detect Gloves with Potential for Virus Penetration
Authors: Kotilainen HR , Cyr WH , Truscott W , Gantz NM , Routson LB , Lytle CD
Published: March 2009

Does the 1000 mL water leak test for medical gloves detect potential for virus penetration? Water leak and virus penetration were determined sequentially in hanging latex surgical gloves (4 brands) with 1000 ml of ΦX174-containing buffered saline (DPBS). Individual fingers (some punctured) were visually examined for water (DPBS) leaks for 2 minutes, then dipped into DPBS for 60 minutes for collection of virus that penetrated the latex barrier. Many punctured and a few non-punctured fingers leaked both water and virus. Some punctured fingers did not leak water nor virus. A few of the control and punctured fingers that did not leak water did allow very low-level virus penetration by 1 hour; 4–50 fold lower than virus penetration from barely-detectable water leaks. Thus, a few gloves with potential for very low-level virus penetration were not detected by the 1000 mL water leak test.
Dry Test Method for Rating the Penetration of Viruses Through Porous Materials Used in Protective Clothing by Health Care Workers
Authors: Placencia AM , Peeler JT
Published: March 2009

Increased concern for the transmission of infectious diseases, primarily AIDS and hepatitis, in the health care setting has led industry, government and the consumer to question the efficacy of protective clothing as it relates to virus transmission. There is a need for the development of standardized methodology under both dry and wet environments for assessing the biobarrier properties of protective clothing. Methodologies are in existence but they are mostly physical-chemical tests which have no correlation to biological tests. This paper describes a dry test method for relating the penetration of viruses to materials used in protective wear. The method uses an exposure chamber into which an indicator bacteriophage (ΦX174) is aerosolized and filtered through discs of material being tested. The phage is collected on a liquid carrier which is assayed for the presence of the indicator organism. The material can be evaluated according to the number of phages that penetrated the material.
The Resistance of Clothing Materials to Biological Liquids
Authors: Henry NW , Montefiori DC
Published: March 2009

Methods to determine chemical resistance of clothing materials have been established by ASTM Committee F23 on Protective Clothing and are widely used, but biological resistant test methods have yet to be standardized. Because of the increased awareness and attention in the health care profession to diseases transmitted in biological liquids containing blood-borne pathogens, there evolved a need to develop performance standards for clothing used to protect against biological liquid penetration. This paper will present the results of a study using ASTM, Method F903-87 for determining resistance of protective clothing materials to penetration by liquids. Challenge biological liquids, human blood and biological culture media containing HIV virus were used to determine the resistance of selected glove and suit materials to liquid penetration. The results show that the method was reproducible and capable of determining biological liquid resistance of clothing to both blood and HIV virus.
Protective Clothing for Health Care Workers: Liquidproofness Versus Microbiological Resistance
Authors: Brown PL
Published: March 2009

Simple simulated in-use tests on protective clothing products, such as leaning with the forearm or elbow on a 0.040 N/m (40 dyne/cm) synthetic blood soaked gauze surgical sponge, have provided both the basis for helping to understand which types of materials, under actual conditions of use, may be capable of providing a liquidproof level of protection and set the ground work for scientific laboratory bench top test device selection and protocol development. However, due to the high limit of detection, liquid penetration testing should only be used as a pre-screening tool to determine which protective clothing materials warrant further investigation with a confirmatory microbiological challenge. A minimum performance standard for liquidproof microbiological protective clothing is recommended. The standard test involves the ASTM F903 Penetration Cell, a one hour test period with a one minute 13.8 kPa (2 psi) pressure pulse, and the Phi-X174 Bacteriophage suspended in a 0.040 N/m microbial media.
Chemical Resistance Properties of Advanced Glove Materials
Authors: Wilusz E , Hassler KD
Published: March 2009

Butyl rubber has been used for many years in chemical protective clothing applications such as gloves, overboots, and coated fabrics used in ensembles for the military and also used in industry. Novel compounds and material configurations have been developed for improved chemical protective gloves based on butyl rubber. The materials were challenged with toluene, 2,2,4- trimethylpentane, 1,5-dichloropentane, and triethyl phosphate. Because of the chemical specific nature of barrier properties, a two-layer approach using elastomers having different solubility parameters was used to provide resistance to hydrocarbons as well as to polar liquids. Poly-(epichlorohydrin)/butyl rubber gloves demonstrated a combination of chemical resistance properties for both hydrocarbons and other chemical hazards. Flame-retardant formulations of butyl rubber were developed using a suitable combination of additives. Gloves from the flame-retardant formulations provide the same barrier properties against the chemicals tested as standard butyl gloves.
Testing the Resistance of Protective Clothing Materials to Nitroglycerin and Ethylene Glycol Dinitrate
Authors: Lara J , Drolet D
Published: March 2009

Permeation tests were performed on several protective clothing materials with a nitroglycerin and ethylene glycol dinitrate-based explosive. In order to perform permeation tests, a modified version of the F-739 permeation cell was used. Breakthrough times showed that the most resistant material was nitrile. In contrast, it was proven that cotton gloves, presently used in the explosives industry to protect workers from contact with dynamite, are the worst barrier. Decontamination of nitrile by washing was evaluated and it was proven to be inadequate. Heat was tried as a decontamination procedure but it requires high temperature and produces degradation of nitrile.
Pesticide Resistance and Thermal Comfort Tests of Protective Clothing in Agriculture
Authors: Hinz T , Jahns G
Published: March 2009

Although exposure measurements show that the stress caused by plant-protective agents is mostly below health risk values and although world-wide less toxic agents are under development, there still remains a risk for the farmer's health and welfare. So it is still a challenge to minimize this remaining risk. The wearing of protective clothing is one possibility. Requirements for each single protective element can be defined from the level of exposure, the toxicological data of agents and the legally stipulated limit values (e.g. NOEL, ADI or other TLV's). This is also valid for other requirements of protective measures like mechanical stability and thermal comfort. For all types of requirements test procedures must be defined to ensure that the given limit values will not be exceeded.
Resistance of Glove Materials to Permeation by Agricultural Pesticides
Authors: Schwope AD , Goydan R , Ehntholt DJ , Frank U , Nielsen AP
Published: March 2009

Using a previously developed test procedure that allows the concurrent measurement of permeation of the active ingredient and the carrier solvent, 115 permeation tests (in triplicate) have been performed with approximately 20 pesticide formulations and 13 glove materials. The carrier solvent was generally found to permeate sooner and at a much higher rate than the active ingredient. The permeation behavior of the formulations containing solvents generally mirrored that of the carrier solvents in neat form. Pertinent to permeation resistance, the better glove materials were nitrile rubber, butyl rubber, and plastic film laminates; natural rubber and polyvinyl chloride were poorer barriers.
Pesticide Protection Through Layered Clothing Systems
Authors: Crossmore DG , Obendorf SK
Published: March 2009

The purpose of this study was to determine whether layering fabrics which are readily available to agricultural workers would reduce penetration of methyl parathion. The fabrics used were cotton denim, cotton printcloth, cotton jersey knit, and polypropylene knit. The two chemically-different knit fabrics (cotton or polypropylene) were used to determine the effect of the second layer's chemical composition on penetration.

Penetration studies were conducted using radiolabeled pesticide. Single layers of heavyweight denim acted as a trap allowing little pesticide to pass through, while the thinner shirtweight fabric was easily penetrated. In two-layer systems that used shirtweight printcloth for the outer layer, penetration was reduced by the presence of the second fabric layer, while air permeability remained unchanged.

Cotton and polypropylene knit fabrics were used as underlayers with the cotton printcloth and were examined for differences in retention and penetration. When a hydrophilic, cotton knit underlayer was used, 55.1% of the applied methyl parathion remained in the underlayer, and just under 44% was in the printcloth. On the other hand, when a hydrophobic, polypropylene knit was used under the printcloth, 7.3% of the applied methyl parathion was retained on the polypropylene fabric, and 92.5% remained in the top layer. The collection pads underneath, designed to measure total penetration through the fabric system, contained equal amounts of pesticide. Since the polypropylene underlayer contained only one-seventh as much methyl parathion as the cotton underlayer, we assume that the polypropylene underlayer had less pesticide available for dermal absorption.
Evaluating the TPP of Clothing Exposed to Electric Arcs: A Standard Laboratory Test Apparatus
Authors: King MW , Menzies RW , Soroka AJ , Dirks E , Chen R , Sun Y
Published: March 2009

Persons required to work close to live electrical distribution lines, transformers and switching equipment are exposed to the risk of burn injuries resulting from accidental electric arcs or flashovers. In order to facilitate the process of designing suitable clothing for protection against such brief high energy exposures, it would be desirable to have an apparatus and test method that could simulate this type of exposure in a routine laboratory environment. This paper reports a major step forward in the design of such testing equipment. The Manitoba Electric Arc TPP (MEAT) tester can reproduce a pre-set arc power with an accuracy of ±5% and deliver incident flux densities in the range of 12–84 kW/m2 (0.3–2.0 cal/cm2.s). Through the use of specially designed software the apparatus will automatically calculate and report the protection time and TPP rating of single fabrics, multilayer assemblies and clothing components. The MEAT tester and proposed test method are currently being considered for incorporation into an ASTM standard.
Sweat Accumulation in Clothing in the Cold
Authors: Nielsen R
Published: March 2009

The influence of various natural and man-made textile fiber types on sweat production, evaporation of sweat and sweat accumulation in the clothing of man during alternating work and rest in the cold was studied. The effect on human heat loss of evaporation of sweat accumulated in different clothing layers was measured on a thermal manikin. Textile material had a significant effect on both the amount of sweat accumulating in the multi-layer clothing ensemble during work in the cold, and on the place where sweat accumulated. The location of the accumulated sweat in the clothing ensemble significantly influenced the heat loss from the thermal manikin during the consecutive drying period. This was explained by a lower efficiency of evaporative cooling of the skin the further away the sweat was located.