bluuebunny/crossref_metadata_2025 huggingface dataset:
Power Plant Instrumentation for Measurement of High-Purity Water Quality
Authors: Brown J
Published: March 2009

Work undertaken by Ontario Hydro, Toronto, to determine levels of feedwater impurities, including corrosion products and condenser cooling water inleakage contaminants, is reviewed. Corrosion product measurement using a grab method gave some useful data but was found to be too labor-intensive. Continuous analysis of corrosion products, in conjunction with a valveless capillary sampler, is now being evaluated as a method. Ion chromatography appears to be a promising technique to determine anions in feedwater. Tests to adapt such an instrument for continuous analysis are planned.
Program for Steam Purity Monitoring: 2. Results of Power Plant Testing
Authors: Peterson SH , Pensenstadler DF , Bellows JC , Hickam WM
Published: March 2009

The steam purity monitoring program of the Westinghouse Electric Corp. has accumulated a large data base on the chemical purity of water and steam in modern fossil fuel power plants. Three types of monitoring have been employed:

(a) grab samples taken during a plant visit and returned to the Westinghouse Research and Development Center for analysis by ion chromatography;

(b) continuous analysis of steam condensate, extracted from the low-pressure (LP) turbine cross-over pipe, using the Westinghouse prototype steam purity monitor; and

(c) total plant surveys of steam and water purity combining continuous analysis of LP steam and grab sampling of multiple locations to permit correlation of impurity levels throughout the plant during all essential operating cycles, including base load, load swings, and a shutdown and hot restart.

The plants that have been studied were selected to provide a variety of designs, including both drum and once-through boilers, various operating pressures, and different types of water treatment. Furthermore, care has been taken to study units that have experienced turbine corrosion and units that have operated for long periods without corrosion problems. Results are presented of this broad program of steam purity monitoring, with attention to the typical chemical environment of turbines in power plants in the United States.
Determination of Anions in High-Purity Water by Ion Chromatography
Authors: Rawa JA
Published: March 2009

Characterization of high-purity waters is a classic analytical problem because of lack of sample integrity as well as inaccuracies in the analytical methods employed for measurement. For industrial process water applications, the purity of water with low dissolved solids content has been traditionally determined by on-line monitoring of specific conductance and sodium. Trace concentrations of cations (sodium, potassium, calcium, and magnesium) present in demineralizer effluents, condensates, and high-pressure boiler and boiler feedwaters have been determined by flame or flameless atomic absorption. Previously, there was no accurate method for measuring trace concentrations of anionic constituents. The introduction of a new analytical technique, ion chromatography (IC), has facilitated the identification and quantitation of several anions—chloride, nitrate, orthophosphate, and sulfate at the micrograms-per-litre level. The IC technique incorporates the concepts of ion exchange and conductimetric detection. Without sample pretreatment, these anions can be accurately detected down to about 50 μg/litre with a 100-μl sample injection. By concentrating the anions in the sample on a special low-capacity anion concentrator column (Dionex Corp.) prior to IC analysis, these same anions can be readily detected at <10 μg/litre. The anion concentrator column technique has been applied successfully to the analysis of high-purity waters from various industrial process water systems. The advantages and limitations of the IC method are discussed.
High-Purity Water Quality Monitoring Based on Ion-Selective Electrode Technology
Authors: Diggens AA , Lichtenstein S , Synnott JC , West SJ
Published: March 2009

Power industry requirements for pure water demand instrumentation capable of detecting contaminants at very low levels. Moreover, precision and accuracy of measurement should be improved to allow reliable control. Although ion-selective electrodes have been employed successfully in the laboratory, certain problems have inhibited their utility in on-line monitoring applications. Recent work, briefly reviewed here, discusses these problems as encountered in the development of a sodium monitor. This effort has resulted in a second generation of ion-selective electrode-based devices which are less complex and, therefore, more reliable. Among these are monitors that measure chloride, chlorine, calcium, and sulfide in the parts-per-billion range. Hardware and chemistries are described, and data resulting from in-house and field evaluations are discussed. Work in progress for other parameters is presented.
Resistivity of Very Pure Water and Its Maximum Value
Authors: Light TS , Sawyer PB
Published: March 2009

Theoretical calculations have been made for the resistivity (and its reciprocal, the conductivity) of pure water in the vicinity of the neutral point at 25°C. A surprising result is that the maximum resistivity is not found at pH 6.998, which corresponds to absolute water, but at pH 7.039, which corresponds to water with approximately 0.8 μg/litre, (parts per billion) of sodium hydroxide added. The resistivities corresponding to these two points are 18.18 and 18.28 MΘ · cm respectively. Although the effect is slight, it will be of interest to users of high-purity water since resistivity is widely used as a criterion for water purity. The temperature coefficient of resistivity is also evaluated.
Precracking of Fracture Toughness Specimens by Wedge Indentation
Authors: Almond EA , Roebuck B
Published: March 2009

A technique devised for precracking single-edge notch beam KIc specimens of cemented carbides has been extended to several nonmetallic materials. The mechanism of formation and growth of a precrack under an indenter is discussed in terms of indentation theory, the material and geometry of the indenter, and the properties of the specimen material. For cemented carbides, the material's fracture toughness and the indenter angle appear to be the most important parameters governing the stability of a precrack, and this is probably true for other materials.

In materials with very fine or poorly defined precracks, it has been shown that a compliance method can be combined with the wedge indentation precracking procedure to enable KIc to be determined without measuring the crack length.
The Character of Cracks In Fracture Toughness Measurements of Ceramics
Authors: Wu CC , Rice RW , Becher PF
Published: March 2009

X-ray microradiographic and in situ SEM techniques that are complimentary and uniquely suitable for characterizing cracks and crack propagation in brittle materials are described. Results obtained from these observations in ceramics show that the cracks are not generally of the ideal character assumed in the typical fracture mechanics analysis. Local microstructure as well as the crystallographic structure of the specimens are shown to be important in determining crack variations. These results are discussed in terms of evaluating and improving the fracture toughness measurements.
Relationship Between Differential Stress Intensity Factor and Crack Growth Rate in Cyclic Tension in Westerly Granite
Authors: Kim K , Mubeen A
Published: March 2009

The laws of fatigue crack propagation in rock may be used to predict life of underground structures for energy storage. The experiments on Westerly granite suggest that this material follows the law da/dN = C(ΔK)m for fatigue crack growth rate and values of C and m are determined. It is observed that m is constant for various ratios of σmin/σmax whereas C is a parametric constant depending upon the stress ratio. The fatigue cracking in Westerly granite is predominantly along the grain boundaries and the crack is often stopped for a long period at such boundaries that are unfavorably disposed.
Application of the Hopkinson Split Bar Test to the Mechanical and Fracture Properties of Rocks
Authors: Buchar J , Bílek Z
Published: March 2009

The experimental results on dynamic response of granite, limestone, basalt and Moravian graywacke are presented and analyzed in this paper. The rock specimens were loaded dynamically in compression by means of the Hopkinson Split Bar Test (HSBT) with a strain rate of approximately 103 s−1 and with the stress pulses having different duration times λε (30 + 80) μs. These dynamic results were used to study the amplitude and frequency response which was then related to the fracture damage.

A new interpretation of stress wave propagation during HSBT, described here, made it possible to identify the complex process accompanying impact rock spalling. Special attention is paid to the dynamic strength and its dependence on strain rate, duration time, and specimen length. The results show that fracture damage has a similar influence to permanent deformation of ductile materials. The equation of state describing the mechanical behavior of investigated rocks was suggested for complicated conditions of impact rock spalling.
Fracture Mechanics of Crack Bands in Concrete
Authors: Cedolin L , Bažant ZP
Published: March 2009

Recent works on finite element models for fracture and cracking of concrete are summarized and reviewed. An element-wide band of smeared cracks represents an effective and realistic model for fracture of plain concrete and reinforced concrete. The criterion for propagation of the band into the finite element in front of the crack band is expressed in terms of the energy consumed to create the cracks. It is shown that a tensile strength criterion, as currently used, is unobjective and gives incorrect convergence as the mesh is refined, with large differences between the results for finite elements of different sizes. However, it is possible to use an equivalent strength which depends on the element size in such a manner that the results are approximately the same as those obtained with the energy criterion. In the case of reinforced concrete, the forces transmitted between concrete and steel must be accounted for in the energy criterion. Furthermore, the bond slip of bars near the crack band must be taken into account, which may conveniently be done in terms of the equivalent free-slip length of steel bars.
Glossary
Authors: Johnson AI
Published: March 2009

In presenting an interdisciplinary symposium on permeability and ground-water contaminant transport, there is considerable chance for lack of communication between the engineers and scientists of the many different disciplines interested in these subjects. To assist in better communication between the disciplines involved in permeability and capillarity testing of soils and rocks, a glossary and conversion factor tables are provided.

Nearly 100 terms are listed alphabetically, followed by brief definitions. Where two or more definitions are listed following a term, no significance is placed on the order of presentation. The source is indicated for each definition, and the sources are listed in the reference section following the glossary. Two tables of conversion factors also are presented to assist in conversion of the units used by the various disciplines.
Correlative Measurements of Pore Size Distribution and Permeability in Soils
Authors: Garcia-Bengochea I , Lovell CW
Published: March 2009

Measurements and use of pore size distributions to explain the behavior of engineering materials are not new. However, there are few, if any, reports of a simplified methodology and its direct application to engineering predictions. This paper explains how pore size measurements and water permeability were correlated for compacted samples of saturated clayey silt. The results strongly support the hypothesis that a new generation of permeability prediction equations is now possible. In the new equations, the old soil parameters of effective grain size, total porosity (or void ratio), and specific surface are effectively replaced by appropriate parameters of the pore size distribution.

The paper recommends the procedure for compacting, saturating, and permeating fine-grained soil samples. Following the permeability tests, small samples are extracted for constant volume dehydration through a quick freeze-sublimation process. Finally, the mercury intrusion technique is used to quantify the distribution of porosity. Study of the distribution plots, particularly the differential frequency one, is very helpful in (a) qualitatively understanding the experimental results and (b) quantifying the data through statistical correlations. Sample data and plots are introduced to reinforce the principal points of the discussion.
Predictive Tools for Contaminant Transport in Groundwater
Authors: Metry AA
Published: March 2009

The management and ultimate disposal of residual waste is subject to stringent programs, many of which were established by enactment of the Resource Conservation and Recovery Act of 1976. Federal and state regulations are now requiring operators of waste disposal sites to minimize environmental impact.

Among the most critical areas of concern is groundwater quality. Previous practices of waste disposal have resulted in many serious episodes of water resource contamination (such as polychlorinated biphenyl disposal in the upper Hudson, arsenic burial in Minnesota, Kepone disposal in Hopewall, Va., the Love Canal, Niagara Falls, N.Y., contamination, and so on). The potential for groundwater contamination could have been reduced if disposal facilities had been located on the basis of their hydrogeologic suitability.

Understanding mass transport mechanisms that influence migration and attenuation of contaminants is a key element in disposal site selection, and design of monitoring and contaminant migration potential are essential in the evaluation of disposal sites and anticipation of groundwater pollution potential.

Among the predictive tools discussed in this paper are mathematical and computer simulation, criteria listing and criteria ranking methods, matrix analysis, and decision tree analysis. This report will include an analysis of the advantages, limitations, and applicability of different tools.
Computer Simulation of Movement of DIMP-Contaminated Groundwater Near the Rocky Mountain Arsenal, Colorado
Authors: Robson SG
Published: March 2009

Diisopropylmethylphosphonate (DIMP) is an organic compound produced as a by-product of the manufacture of a chemical munition at the Rocky Mountain Arsenal, Colo. Groundwater contamination occurred when industrial effluent containing DIMP seeped into the water table below unlined industrial waste-disposal ponds during 1952 to 1956. In 1975, groundwater containing DIMP was found in a 73 km2 (28-mile2) area to the northwest of the arsenal and was detected within 1.6 km (1 mile) of municipal water wells supplying the city of Brighton, Colo. The DIMP concentrations in the groundwater ranged from 0.5 µg/litre, the analytical detection limit, to as much as 44 000 µg/litre near the abandoned waste-disposal ponds. A mathematical model was used to simulate the movement and concentration of DIMP in groundwater near the arsenal to determine the historical distribution and concentration of the contaminant and to predict the possible future distribution of the contaminated groundwater.

Model simulations of historical DIMP movement in the alluvial aquifer indicate that the contaminated groundwater flowed rapidly to the northwest and began discharging into the South Platte River about 4 years after the contaminant first entered the aquifer. It is estimated that from 1958 to 1960 the mean annual DIMP concentration was 30 µg/litre in the river. Modeling indicates that mean annual DIMP concentrations in the river have decreased since the period 1958 to 1960 to less than 1 µg/litre in 1976.

Model simulations of future DIMP movement in the aquifer indicate that groundwater containing DIMP in excess of 0.5 µg/litre will not reach the Brighton municipal wells by 1995, even if no remedial measures are taken to prevent the discharge of DIMP-contaminated groundwater into an irrigation canal which recharges the aquifer near Brighton. A barrier impermeable to groundwater movement, now under construction at the northern arsenal boundary, is shown by the model to be an effective means of stopping off-arsenal movement of the contaminated groundwater without producing adverse effects on the water levels in the aquifer.
Attenuation of Radionuclides and Toxic Elements by In Situ Soils at a Uranium Tailings Pond in Central Wyoming
Authors: Haji-Djafari S , Antommaria PE , Crouse HL
Published: March 2009

Existing concentrations of radionuclides and arsenic in a uranium tailings pond and groundwater, and hydrogeologic and mass transport parameters were utilized in a Galerkin-based finite element mass transport model to predict future migration potential for discrete chemical species. Field and laboratory data and the results of computer modeling indicate that movement of chemical species of interest at the subject site is mitigated by chemical reaction with in situ soils including precipitation, coprecipitation, and ion exchange. The study showed that among the hydrogeologic and mass transport parameters, distribution coefficients are the major controlling factor in determining the extent of attenuation of radionuclides and arsenic. These coefficients are specific to individual chemical species and are highly dependent on groundwater pH conditions and particular soil characteristics.
Acoustic Emission Monitoring of Soil and Rock Grouting
Authors: Huck PJ , Koerner RM
Published: March 2009

Grouting in soil or rock is by nature difficult to monitor and evaluate. Recent developmental efforts and demonstrations on construction projects have shown that acoustic emission monitoring shows promise in its use before and after grouting to indicate the effectiveness of the grout in stopping groundwater seepage, and during grout injection to detect hydraulic fracturing. The latter application has the potential for permitting the use of increased injection pressures, and hence productivity, while actually decreasing the risk of extensive hydraulic fracture during injection.
Acoustic Emissions During Creep of Frozen Soils
Authors: Fish AM , Sayles FH
Published: March 2009

Deformation, time-dependent failure, and acoustic emissions during unconfined compression tests of frozen Fairbanks silt were studied. Acoustic emissions (AE) are detected when the applied stress exceeds a threshold level. This threshold stress is related to the limit of long-term strength of the frozen soil. Under stress exceeding the limit of the long-term strength, the accumulation of acoustic emissions with time can be correlated with creep deformation; that is, plots of the cumulative number of acoustic pulses versus time have shapes similar to those of creep curves with primary, secondary, and tertiary stages. Such correspondence made it possible to describe both phenomena from the viewpoint of the unified kinetic theory of strength. Experimental data are presented, and unified constitutive equations describing deformations, time-dependent failure, and the accumulation of the acoustic emissions during short-term creep of frozen soils are derived. The time to incipient failure, when the AE rate reaches a minimum, is considered to be the most important characteristic of a creep process. It is shown that this time can be predicted theoretically if the parameters of the AE process and the stress state of the frozen soil are known.
Future Distillate Fuels: What, When, Where, and How Stable?
Authors: Brinkman DW , White EW
Published: March 2009

While there are several alternative sources of middle distillate fuels, each has its own problems and limitations. Storage and thermal stability will become increasingly important as liquids from coal and shale become a part of the commercial stream. Stability testing implies that the severity of processing required will be controlled by the level of stability specified.
Stabilization of No. 2 Fuel Oils with Caustic Treating and Additives
Authors: Powers EJ , Wotring WT
Published: March 2009

A combination of caustic treating and additives is used in the refinery to stabilize No. 2 distillate fuels to prevent the formation of insoluble gum and color degradation in long-term ambient storage. Cracked components are treated with caustic to remove reactive compounds such as thiophenols. Straight-run components are not treated. Blends of treated cracked components and untreated straight-run components can be further stabilized with commercial additives to limit insoluble gum formation to 2 mg/100 cm3 after storage for 16 weeks at 43.3°C.
Army Needs for Diesel Fuel Stability and Cleanliness
Authors: Stavinoha LL , Westbrook SR , LePera ME
Published: March 2009

This paper reviews the general topic of fuel deterioration. Primary emphasis is on diesel fuels used in compression ignition engines, which power the majority of Army tactical and combat vehicles. Field problems regarding the fuel stability and related problems are summarized, and the status of on-going research and development programs is outlined. This information places in perspective the background which has prompted current research activities to detect, predict, and prevent fuel stability-associated equipment failures. Concern for anticipating deleterious product formation in current and future fuel formulations composed of diverse petroleum crude and synthetic (shale or coal) crude oils, fuel/equipment interactions, diverse storage conditions, and the increased desire for prolonged storage periods provides the driving factors in defining the Army's fuel stability research programs. While placing these concerns in perspective, the Army's present and future needs for diesel fuel stability and cleanliness control are identified.
Reproductive Tests of Diazinon on Bobwhite Quail
Authors: Stromborg KL
Published: March 2009

Diazinon was fed at sublethal levels to reproductively active bobwhite (Colinus virginianus). Thirty pairs were given constant concentrations (0, 35, 50, 72, 104, or 150 ppm) for 3 weeks (Constant group). Another 30 pairs (Pair-fed group) were matched to these by body weights and were fed the amounts of untreated food consumed by corresponding Constant pairs to evaluate the effect of food deprivation. To mimic environmental degradation, a group of 30 pairs (Decreasing group) was initially given diazinon at the same concentrations as the Constant group; the concentration was decreased geometrically every 3 days to yield a 50 percent reduction in 15 days. Following 3 weeks of exposure to the experimental diets, pairs were maintained for an additional 3 weeks on untreated food to measure the birds' recovery. Food consumption, egg production, and hatchability were recorded for each pair. Individually hatched chicks were banded and kept for 2 weeks to monitor their survival. Food consumption was negatively dose-related above 35 ppm in the Constant and Decreasing groups. The only reproductive parameter affected was egg production. Production declined as the dose was increased above 35 ppm in the Constant and Decreasing groups. Egg laying was reduced more in the Constant than in the Decreasing pairs. The egg-laying rate of the Constant and Pair-fed groups differed; this difference was reflected by a threshold corresponding to 72 ppm in the Pair-fed group as opposed to 35 ppm in the Constant group. Residual effects of prior treatment on food consumption and egg production were observed in the Constant and Pair-fed pairs during the posttreatment period, but the Decreasing pairs were not influenced by prior treatment. The magnitude of effects related to the dose was not as great during the posttreatment period as during the treatment period and represented the recovery from diazinon effects over the span of the posttreatment period. The schedule of doses for the Decreasing group ameliorated the deleterious effects of diazinon, whereas the dosing schedule for the Constant group yielded a small overestimation of hazard to wildlife.
Diagnostic Brain Residues of Dieldrin: Some New Insights
Authors: Heinz GH , Johnson RW
Published: March 2009

Forty adult male cowbirds were fed a diet containing 20 ppm dieldrin; 20 of the birds were randomly selected to die from dieldrin poisoning and 20 were sacrificed when dieldrin had made them too sick to eat. An average of 6.8 ppm dieldrin (range of 1.51 to 11.7) in the brain on a wet-weight basis was associated with a treatment-related cessation of feeding, whereas an average of 16.3 ppm (range of 9.84 to 23.5) was found in the brains of birds that died from dieldrin poisoning; the latter concentrations agreed with those determined in other studies. Dieldrin-induced starvation was generally irreversible; therefore, brain levels of dieldrin that are clearly sublethal may nevertheless present a grave hazard to birds by initiating a process that leads to death. Fatter cowbirds were able to survive longer on dieldrin treatment but contained brain residues similar to those in cowbirds that died sooner. Some cowbirds survived for 2 months or longer with unexpectedly large amounts of body fat remaining when they died or were sacrificed. Fatter cowbirds also survived longer after they had stopped eating.
Formalin Preservation of Avian Blood for Organochlorine Analysis
Authors: Stafford CJ , Stickel WH
Published: March 2009

Blood biopsy for chemical analysis is a valuable technique for evaluating chemical exposure of birds in the wild without harming the birds. Field conditions, however, often make sample storage difficult. Better methods than freezing are needed to improve the interpretive value of chemical analysis of the sample. The use of formalin was explored for this purpose. A pooled sample of blood containing naturally incorporated 1,1-bis-(p-chlorophenyl)-2,2,2-trichloroethane (DDT), 2,2-bis-(p-chlorophenyl)-1,1 dichloroethylene (DDE), and dieldrin was subdivided into 30 samples, of which 10 were frozen, 10 more were kept at room temperature, and 10 were formalinized by adding 1 part of chemically pure formalin to 20 parts of blood. The formalinized samples yielded the highest and least variable concentrations of chemicals. The field procedures are outlined.
Subacute Dietary Toxicities of Dicrotophos and Dieldrin in Time-Replicated Trials with Young Ring-Necked Pheasants and Mallards
Authors: Hill EF
Published: March 2009

The dietary toxicities of (E)-phosphoric acid 3-(dimethylamino)-1-methyl-3-oxo-1-propenyl dimethyl ester (dicrotophos) and 3,4,5,6,9,9-hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-dimethanonaphth[2,3-b]oxirene (dieldrin) to 10-day-old ring-necked pheasants (Phasianus colchicus) and 5-day-old mallards (Anas platyrhynchos) were compared in five time-replicated trials. Toxicities were calculated as median lethal concentrations (LC50s) based on 5 days of ad libitum feeding on geometrically spaced concentrations of toxicant. The LC50s were more uniform for dieldrin than for dicrotophos with both species and more uniform for pheasants than for mallards with both compounds. The LC50s of dieldrin and dicrotophos averaged 59 [standard deviation (SD) = 4.4] and 45 ppm (SD = 5.0) for pheasants, and 156 (SD = 24.9) and 102 ppm (SD = 24.9) for mallards. Changes in LC50s between successive trials, although possibly haphazard, were nearly always in the same direction for both compounds with both species. Feeding rates at various concentrations of equivalent potency gave meaningful insight into the sensitivity and vulnerability of both species to these insecticides. Comparisons of 5 and 10-day-old mallards demonstrated the importance of age differences to interpretation of short-term subacute toxicity data. For example, at 5 days dicrotophos was 1.5 times more toxic than dieldrin, but at 10 days dieldrin was 2.6 times more toxic. These differences are explained.
A Short-Term Dietary Toxicity Test on Small Mammals
Authors: McCann JA , Teeters W , Urban DJ , Cook N
Published: March 2009

The U.S. Environmental Protection Agency (EPA) requires that the results of certain toxicity tests on wildlife and aquatic organisms be submitted to the agency for evaluation before a new pesticide can be federally registered. The results of these toxicity tests are used to address the potential acute hazards of a pesticide's use to wildlife and aquatic organisms. At the present time an acceptable short-term feeding method for small mammals is not available. The EPA has been using the results of data submitted to support human safety requirements [primarily the rat single-dose oral median lethal dosage (LD50) data] to assess the hazards of pesticide residues in and on food to mammalian wildlife. We believe that these data may not properly represent the toxicity of a pesticide residue to mammalian wildlife. The objectives of the present study were three-fold: (1) to develop an acceptable short-term dietary LC50 test for small mammals, (2) to evaluate the test method by testing a number of chemical pesticides, and (3) to determine the relationship between the rat LD50 and median lethal concentration (LC50) values. The proposed 5-day LC50 test uses laboratory rats (Wistar strain) and is similar to a published avian dietary LC50 study. It consists of a 5-day acclimation period, a 5-day exposure to treated food, and a posttreatment observation period lasting for at least 9 days. The initial studies involved the exposure of five male and five female rat groups to each of five concentrations of treated food and one untreated group for control. The mortality, body weights, and food consumption were recorded. The mortality data were used to calculate LC50 values, which are presented for 17 pesticides. The experimentally determined LC50 values for rats were compared with derived ones calculated from published rat LD50 values. The derived values were not toxicologically equivalent to the LC50 values determined from our tests. Data are presented that indicate to us that rat LC50 values are a better measure of the toxicity of pesticide residues to mammalian wildlife than are rat LD50 values. Incorrect decisions on acute hazards of pesticide residues can result from the use of rat LC50 values calculated from rat LD50 values.
Acute and Subacute Toxicity of Pesticides in Microtine Rodents
Authors: Cholakis JM , McKee MJ , Wong LCK , Gile JD
Published: March 2009

Acute oral median lethal dose (LD50) and 30-day dietary subacute median lethal concentration (LC50) studies of ten selected pesticides were evaluated in microtine rodents. Four species of microtine rodents, including Microtus orchrogaster (MO), Microtus canicaudus (MC), Microtus pennsylvanicus (MP), and Microtus montanus (MM) voles, were used as a means of developing new animal model systems. Data from both the acute and the 30-day subacute studies revealed that MC voles were approximately twice as sensitive to these pesticides as MO voles. Based on the acute studies, the overall order of pesticide toxicity was parathion > methyl parathion > dieldrin > 2,4-dichlorophenoxyacetic acid (2,4-D) > 2,4,5,-trichlorophenoxyacetic acid iso-octyl esters (2,4,5-T) > simazine > propanil = pentachloronitrobenzene (PCNB) = hexachlorobenzene (HCB) = trifluralin. The general order of species sensitivity was as follows: MC > MP ≥ MO ≥ MM. No apparent sex differences were observed in the MP, MO, or MM voles. In the MC voles, the female appeared to be two to three times more sensitive to methyl parathion than the male. Based on the 30-day subacute LC50 studies, the overall order of pesticide toxicity was dieldrin > parathion > methyl parathion > HCB > 2,4,5-T > PCNB > propanil. The toxicological signs were similar to those of general pesticide intoxication observed in laboratory animals such as rats and mice. No gross pathology attributable to pesticide treatment was observed. Based on LD50 values, the laboratory rodents appeared to be more susceptible to 2,4-D, dieldrin, methyl parathion, parathion, propanil, and 2,4,5-T; equally susceptible to HCB, PCNB, and trifluralin; and less susceptible to simazine than the MC voles.
Measuring Surface Texture by the Sand-Patch Method
Authors: Chamberlin WP , Amsler DE
Published: March 2009

Components of variance were analyzed for 720 measures of concrete pavement texture depth obtained by the sand-patch method. The measurements were made in connection with a complete factorial field experiment involving four texturing methods used on two sections each of five different paving jobs. Each pavement section was tested at three different sites by three different operators performing two tests each. The analysis permitted estimates of the repeatability and reproducibility of the sand-patch test, as well as errors that can be expected in measuring the mean texture depths of a section of textured pavement.
Macrotexture and Drainage Measurements on a Variety of Concrete and Asphalt Surfaces
Authors: Yager TJ , Bühlmann F
Published: March 2009

As part of a major study to develop methods for predicting tire friction performance on all types of pavements, macrotexture measurements were taken on a variety of concrete and asphalt surfaces using several different volumetric and drainage techniques. Expressions are developed which relate data obtained with each technique. Factors influencing these measurements, including operator technique and type of equipment, are identified. Comparisons also are given with skid resistance values obtained using a British portable pendulum tester. Outflowmeter measurements are presented to show the effect of surface finishes and treatments on drainage characteristics. The need to measure other surface texture parameters, such as microtexture, is suggested from comparative tire friction and surface macrotexture data obtained on two different wet surfaces. The paper concludes with comments relative to the necessity for additional studies to evaluate different surface microtexture measurement techniques in an effort to provide sufficient information to enable researchers to predict tire-pavement friction performance.
Ontario's Wet Pavement Accident Reduction Program
Authors: Kamel N , Gartshore T
Published: March 2009

Ontario's approach to the identification and treatment of black spot highway locations is presented. Highway locations with an excessive rate of wet pavement accidents are identified and ranked utilizing Ontario Ministry of Transportation and Communications computerized accident data files. Criteria for site selection, procedures for subsequent site investigation, and selection of appropriate remedial measures are outlined and discussed.

Rehabilitation of pavements with low friction levels, and experiencing a high rate of wet pavement collisions, has resulted in substantial reductions in accidents. Collision data before and after treatment at various sites are presented.

This paper provides design and performance information on modified bituminous surface course mixes currently used by the Ministry. Such mixes maintain better surface textures and provide longer lasting skid resistance characteristics. These mixes are used for black spot treatments, and in new surface construction on main highways.
Design and Performance Aspects of Antilock Brake Control Systems
Authors: Brewer HK
Published: March 2009

This paper analyzes the general requirements of antilock brake systems in decreasing vehicle stopping distance and maintaining directional control during braking. The dual phenomenon of tire slip and vehicle dynamic weight transfer, which necessitate the use of antilock systems for high-efficiency braking performance, is discussed. Also, a review of the present level of antilock technology development as well as specific system configurations is presented for aircraft, automobiles, heavy-duty trucks, and motorcycles.
On-Road Test Facility for Truck Tire Rolling Resistance and Bearing Losses Measurements
Authors: Bosik AJ , Lougheed JH
Published: March 2009

A rig has been designed and built for the on-road measurements of rolling resistance and bearing friction losses for free-rolling tires of large trucks. The rig comprises a force bridge, axle, suspension, and two sets of dual wheel assemblies mounted on a 13.7-m (45 ft) flatbed trailer which is towed at normal highway speeds. The rig is designed to be used over a wide range of ambient temperature conditions as well as road surface types. The tire cavity temperatures are monitored and the tire inflation pressures are regulated through a slipring and rotary seal assembly. A quick-lift auxiliary axle is also mounted on the trailer for transporting the rig when no measurements are being made as well as for braking and other safety reasons. The outputs of six load cells, two inclinometers, and a tangent angle-rolling radius device are used to automatically determine the rolling resistance forces, bearing moments, and the vertical and transverse tire loads. Instantaneous values of these outputs and the outputs of temperature and pressure sensors can be monitored during testing and are recorded on an on-board computerized data acquisition system for further data reduction.

Preliminary on-road testing has demonstrated that the force bridge is highly sensitive and the values of rolling resistance and bearing moment are of the right magnitude.
Effects of Surface Curvature and Texture on Passenger Car Tire Noise Generation on Roadwheels and Roadways
Authors: Donavan PR , Oswald LJ
Published: March 2009

Differences in surface curvature and surface texture are the only possible explanations for the differences in the noise of passenger car tires measured on-road and on a laboratory roadwheel. To determine the individual effects of curvature and surface texture, acoustic intensity measurements were made alongside four passenger car tires operating on roadwheel and roadway surfaces as the two parameters were varied independently. In the study, curvature was varied by using roadwheels of varying diameters and a flat roadway. Surface texture was varied both on the roadwheels and on the roadway. The results show that differences in surface texture account for most of the differences observed between noise measured on-road and on a roadwheel. Curvature effects were found to be minor over the range investigated here (roadwheels with diameter greater than 1.7 m). It was also observed that another important parameter in causing differences is direction of tire rotation and measurement side of tire.
A Four-Point Shear Test for Graphite/Epoxy Composites
Authors: Browning CE , Abrams FL , Whitney JM
Published: March 2009

The consistent inability of the short-beam shear (SBS) test to yield the desired interlaminar shear failure mode in thin-beam specimens of graphite/epoxy has led to the development of an alternative test method, the four-point shear (FPS) test. In the course of this developmental effort, four different shear specimens were investigated: a thin-beam 16-ply SBS specimen, a thick-beam 50-ply SBS specimen, a thin-beam 16-ply FPS specimen, and a slightly thicker 24-ply FPS specimen. All specimens were tested to failure, the resulting data were statistically analyzed, and the fractured surfaces were examined with a scanning electron microscope (SEM). The 16-ply SBS specimen never produced an interlaminar shear failure and therefore was considered unacceptable. The thick 50-ply SBS specimen consistently produced shear failure modes and corresponding failure surfaces and a very narrow data distribution. However, the thick-beam specimen is not an attractive alternative, since it poses cost and fabrication difficulties inherent to thick composites. The FPS specimen was found to be an effective alternative to the thin-beam SBS specimen. It consistently produced interlaminar shear failure modes and corresponding failure surfaces and a reasonable data distribution. In addition, the FPS specimen retains the attractive features of the thin-beam SBS specimen, being small, thin, easily machined, and employing a simplified test method. Therefore the FPS test warrants serious consideration as an alternative to the thin-beam SBS test.
Some Viewpoints on Evaluation/Accreditation Systems
Authors: Dymond DM
Published: March 2009

This paper describes the early development of ASTM Standard E 548, Recommended Practice for Generic Criteria for Use in the Evaluation of Testing and Inspection Agencies. It describes some of the essential concepts developed by Committee E-36 and its task forces and shows how these concepts relate to the work of other ASTM committees and to national and international accreditation programs. He defines the goals of a successful accreditation system as (1) credibility and (2) acceptance. He hopes that ASTM through its Committee E-36, working with the other ASTM committees and outside organizations, can provide national and international leadership in the development of accreditation systems.
Toward Adoption of a Universal Laboratory Accreditation Criteria
Authors: Locke JW
Published: March 2009

This paper presents a comparison of five laboratory accreditation criteria in six basic categories: organization, human resources, material resources, operating procedures, record keeping, and other. A brief analysis of each set of criteria points out their strengths and weaknesses. The intent of the paper is not to present a proposed set of universal criteria but rather to present comparisons of the elements of the criteria in order to assist standards development organizations to expedite the evolution of such a universal set of criteria.

Laboratory accreditation criteria for measuring the competence of testing laboratories significantly affects the acceptance of test data produced by laboratories in different accreditation systems. In determining whether one system will accept test data produced by laboratories accredited by another system, a detailed comparison of criteria used by each system must be made. Differences must be resolved, either by accepting the fact that one or more criteria are absent in one system as compared to another or else by causing the criteria in one or both systems to change so that the criteria in both systems are in harmony with each other.
Quality Assurance in a Coal Analysis System
Authors: Graham RD
Published: March 2009

The rebirth of coal as a fuel and feedstock has increased the concern about and the need for accurate and precise analytical results. As environmental policies and regulation become more stringent and as worldwide energy costs continue to rise, the economic incentives associated with compliance testing increase. This presentation explains how one coal producer is attempting to meet this need for timely, cost-effective analytical results and how this relates to accreditation activities.
A Public Utility's Approach to Evaluating Laboratory Test Activities
Authors: Woodall WR
Published: March 2009

The purpose of this paper is to discuss a public utility's approach to obtaining satisfactory and reliable evaluation, verification, and accreditation of its laboratory testing. These activities include fuel testing, chemical testing, identification and analysis of biological samples, testing of electrical equipment, and the like. An essential need is to demonstrate credible results and test procedures that will be accepted by regulatory agencies, fuel vendors, and the courts if necessary.

This paper will present the pros and cons of several evaluation techniques. These include a company-wide quality assurance program, sample verification by expert consultants and third party laboratories, split sample analyses with vendor laboratories and sister utilities, and sample splits with government laboratories.

The licensing or certification of individuals, laboratories, and equipment is important in the context of this discussion. Although individuals and equipment can be tested and certified, it is difficult to certify technique in the daily laboratory routine. This paper will also review the concept of a national standardized accreditation program versus accreditation by professional societies and organizations closely allied to certain disciplines.
Quality Assurance at the Ford Motor Company Central Laboratory: A Dynamic Approach to Laboratory Quality
Authors: Gaft S , Richards FD
Published: March 2009

Quality assurance can be realized by integrating the concepts of quality of data, certified calibration of equipment, and approved methodology. At the Ford Motor Company Central Laboratory, this is accomplished by enlisting employee commitments to quality into a program that measures the laboratory output (reports) for equipment calibration and standards, test methods and sampling, overall report quality, and record retention. This paper describes a quality assurance program developed and implemented at Central Laboratory in 1978. The program has been readily accepted by laboratory management and engineers and has yielded an impressive reduction in significant discrepancies in laboratory reports since its inception.
Quality Assurance Requirements for Automated Water Quality Laboratories
Authors: Barton GW
Published: March 2009

In the course of assisting the U.S. Environmental Protection Agency and the U.S. Geological Survey in automating their water quality surveillance laboratories, quality assurance requirements for this function have been investigated in detail. It was found that while computerization of instruments and functions can be of great assistance in operations, scientific insight must, in the end, be the final judge of quality. These laboratories engage in several kinds of activities that differ in important details. One of them had the primary mission of analytical methods development and validation. Another was an analytical facility for sewage treatment process development. The others engaged in three different activities, special surveys to establish baseline water standards, routine surveillance to detect variations from baseline, and special studies to collect the data for action against polluters. The similarities and differences of requirements in these various situations will be discussed.
Evolution of the National Voluntary Laboratory Accreditation Program Procedures
Authors: Unger PS
Published: March 2009

The Department of Commerce published its original procedures for the operation of the National Voluntary Laboratory Accreditation Program (NVLAP) on 25 Feb. 1976. Three revisions have been made since then and another is currently under consideration. This paper briefly reviews the development of the NVLAP procedures since they were proposed in May 1975.
The U.S. Army Environmental Hygiene Agency Analytical Quality Assurance Program
Authors: Sneeringer PV , Belkin F , Puzniak RW , Costick SA
Published: March 2009

The U.S. Army Environmental Hygiene Agency supports the worldwide health and environment programs of the Army through consultations, supportive services, investigations, and training. To aid in this mission, USAEHA maintains an Analytical Quality Assurance Program for its Aberdeen Proving Ground and Regional Laboratories. The program encompasses the analytical areas of air pollution chemistry, water and waste water chemistry, industrial hygiene chemistry, toxicology, clinical chemistry, and radiochemistry. The program includes standardized quality control procedures, regular inspections and audits, and peer review.
The Development of National Laboratory Accreditation Schemes with International Acceptance in Mind
Authors: Stanger DH
Published: March 2009

The development of the United Kingdom’s National Testing Laboratory Accreditation Scheme is used as an example of the progress being made to effectively coordinate existing approval agencies so as to minimize the burden on laboratories being accredited while maximizing the benefits derived from accreditation schemes. Also discussed are the support required from governments and the role of the International Laboratory Accreditation Conference.