bluuebunny/crossref_metadata_2025 huggingface dataset:
Applications of Heat Flux Transducers: A Select and Annotated Bibliography
Authors: Bomberg M
Published: December 2008

This paper is a select and annotated bibliography dealing with the construction of heat flux transducers, their calibration and error verification, and the methods used for thermal resistance determination.
Characterization of Submicrometre Surface Layers by Indentation
Authors: Pollock HM , Maugis D , Barquins M
Published: December 2008

With our instrument, the penetration depth of a three-faced indenter is continuously measured during both indentation and unloading. Useful loads are about 10 μN to 30 mN (1 to 3000 mg). The specimen can be transferred between two locations (test and microscopic observation); a particular area can be relocated by means of a computer-controlled three-dimensional movement. Scratch hardness testing with measurement of frictional force can be performed at speeds as low as 30 nm/s. The general shape of the depth/load graphs, together with measurement of hysteresis and slope, gives an initial characterization of the specimen. Further analysis involves various theoretical topics, which we review in the light of recent literature. These include the way in which a variation of yield stress with depth will affect the measurements and the surface effects, such as the contribution of surface energy to the effective applied load. A controversial topic is the extent to which the depth of indentation in metals, relative to the mean distance between preexisting dislocations or grain boundaries, can lead to a true size effect, or even a critical load below which no plastic deformation occurs. Indentation creep may be significant even for metals such as steel and nickel at ambient temperature.

Accordingly, the concept of microindentation hardness as a material property can be of doubtful value for depths in the 10 to 100-nm range; the apparent mean pressure can be characteristic of a depth much greater than that of the plastic indentation. However, it is still possible to obtain measurements within this depth range, to deduce the type of regimen (for example, elastoplastic or fully plastic), and to derive alternative semiempirical indexes of the extent of plastic deformation, elastic recovery, and time-dependent behavior.
Measurement of Hardness at Indentation Depths as Low as 20 Nanometres
Authors: Oliver WC , Hutchings R , Pethica JB
Published: December 2008

Hardness as a function of depth is examined over a wide range of depths in gold, nickel, lithium fluoride (LiF), and silicon. To examine hardness in very shallow indents (100 nm), a special hardness tester with 2.5-μN load resolution and 0.2-nm indenter displacement resolution was used. The tester monitors the load continuously as the load is applied and removed. The hardness is calculated using the depth measurements. Images of indents in the scanning electron microscope (SEM) and transmission electron microscope (TEM) are used to check that the expected contact areas are achieved. It is shown that the contact area can be calculated if elastic effects are accounted for. The loading and unloading portions of the curves are discussed in detail. Attention is paid to the mechanisms of hardness changes with depth and the effects of elastic recovery on contact area measurement.
Dislocation Aspects of Plastic Flow and Cracking at Indentations in Magnesium Oxide and Cyclotrimethylenetrinitramine Explosive Crystals
Authors: Armstrong RW , Elban WL
Published: December 2008

Unique information about the hardness properties of crystalline materials can be obtained from studying the dislocation mechanisms involved in microindentation testing. The dislocation description provides information in addition to the knowledge of indentation processes gained from earlier continuum mechanics analyses and from models of the orientation dependence of hardness based on the geometrical arrangement of slip systems. For example, (1) mapping of the residual dislocation distributions within microindentation plastic zones can be used to characterize the deformation field and (2) specification of the dislocation interactions that occur among the crystal deformation systems is useful in evaluating the extent to which the hardness is affected by work hardening and cracking mechanisms. An interesting application of this information is to microindentation hardness testing of explosive crystals.
Microindentation Hardness Measurements on Metal Powder Particles
Authors: Shives TR , Smith LC
Published: December 2008

The National Bureau of Standards has undertaken a rather extensive metal processing program whereby metal powders will be produced by the inert gas atomization process. Powder particle sizes are expected to range from about 10 to 100 μm in diameter. Part of the overall program is the determination of the mechanical properties of the individual powder particles in the as-produced condition. Conventional microindentation hardness is one of the techniques that is planned to be employed for the characterization of mechanical properties. In order to determine the applicability of this technique to very small particles, commercially available and experimental powders ranging in size from 3 to 165 μm have been mounted in various metallographic mounting media as well as in an electrodeposited metal mounting medium in order to evaluate the effects of the properties of the mounting materials on the measured hardness values. The effects of different applied loads and variations in particle size are also evaluated.
Indentation Hardness of Surface-Coated Materials
Authors: Vingsbo O , Hogmark S , Jönsson B , Ingemarsson A
Published: December 2008

A model for the mechanical interaction between a deposited surface film and its substrate during indentation is investigated for a number of material combinations. Linear relationships between the indentation microhardness and the inverse of the indentation diagonal are found for indentations larger than a limiting size, for both coated and uncoated materials. These relationships are used for measuring the hardening effect of a harder coating on a softer substrate and for finding separate hardness values characteristic of the film and the substrate materials.
Knoop Microhardness Testing of Paint Films
Authors: Walker WW
Published: December 2008

A standard method of determining the relative hardness of dried paint films is the ASTM Test for Film Hardness by Pencil Test [D 3363-74 (1980)]. Although the pencil test is useful in comparing the film hardness of paint systems, it does not yield specific numerical hardness data. Pencil hardnesses are alphanumerical and therefore pseudoquantitative. In order to quantify hardness results from the pencil test, a correlation was sought between pencil hardness and Knoop microindentation hardness. First, the Knoop microindentation hardness of a set of drawing leads meeting the requirements of ASTM Test D 3363-74 (1980) was determined. A linear correlation was found between pencil lead hardness numbers and Knoop microindentation hardness values. The Knoop microindentation hardness was next determined on a series of painted panels of known pencil hardness. A useful correlation was found between the film hardness as determined by the pencil test and that found by the Knoop microindentation hardness test.
Optimizing Reproducibility in the Analysis of Polymers by Steric Exclusion Chromatography
Authors: Miller R , Dalton G
Published: December 2008

Several potential sources of variation in steric exclusion chromatography (SEC) are discussed: flow rate stability of the pump, column temperature, data processing, and the chromatography itself. Many of these variation sources may be minimized by careful attention to analytical techniques. Flow-rate stability, however, is a function of the chromatographic hardware used and is not as readily subject to control. Experimental techniques are described whereby relative standard deviations below 0.3% in the routine determinations of molecular-weight averages may be achieved on an optimized chromatographic system.
Use of the Automatic Capillary Rheometer in Quality Control
Authors: Sholley CK
Published: December 2008

Manufacturing problems can be classified into two distinct categories: first, problems caused by equipment or process variables such as operating temperatures or pressures, screw speeds, die, screw and mold design, injection times, and so forth. The second category is problems caused by differences in the flow characteristics of resins and compounds (material variables). This paper will address the second category of material differences and show how they can be detected before processing through use of an instrument such as the automatic capillary rheometer (ACR).

The test method historically used for ensuring resin and compound uniformity has been the melt indexer or melt plastometer. The melt index test, however, is limited in relating polymer flow properties to actual processing conditions. It provides information only at low shear rates. Actual factory processes, such as calendering, extrusion, injection molding, transfer molding, and so forth, are performed under moderate to high shear rate conditions. The ACR is capable of measuring the viscosity of resins and compounds over the total range of processing shear rates thereby providing information relative to actual processing.

Use of the ACR in a quality control environment will be discussed along with data interpretation.
Compression Ring Environmental Stress Crack Resistance (Pipe) Precision and Accuracy Round Robin
Authors: DeBlieu IK , Palermo EF
Published: December 2008

ASTM Committee F-17 on Plastic Piping Systems is developing a precision and accuracy statement for the Proposed Practice for Determination of Environmental Stress Crack Resistance (ESCR) of Polyethylene Pipe (1983 Annual Book of ASTM Standards, Vol. 8.04). The objective is to establish this proposed practice as a standard test method. This paper describes the results of the first round robin, which by the wide range of results demonstrates the need for explicit definition of test procedures. The data of the round robin are presented and the next steps necessary to successfully complete the precision and accuracy statement are described.
Study of Stress Corrosion Cracking Susceptibility of Type 316L Stainless Steel In Vitro
Authors: Sheehan JP , Morin CR , Packer KF
Published: December 2008

Post-failure analyses of Type 316L stainless steel implants have frequently implicated stress corrosion cracking as the mode of failure. If stress corrosion cracking of this stainless steel is likely in vivo, this material would have questionable utility for such applications. However, this material is widely used by manufacturers and approved by government regulating agencies. This study was designed to critically evaluate this issue. No susceptibility to stress corrosion cracking of 316L was found in manufactured implants or in specimens from implant quality material in vitro by both static loading and slow strain rate testing techniques. An adjunct in vitro fatigue study disclosed multiple fatigue cracks with branching tendencies. It is concluded that crack branching and secondary cracking in 316L implants are not adequate indicia of stress corrosion cracking of implants.
An Electrochemical Test for the Evaluation of Sulfide Tarnishing of Dental Alloys
Authors: Marek M
Published: December 2008

Tarnishing of gold and silver alloy dental restorations in service is caused mainly by the formation of sulfide films. Since the reactions are electrochemical in nature, electrochemical techniques can be used to examine them. In this study, a practical test of the susceptibility to sulfide tarnishing was designed, based on coulometry at constant potential in an aqueous sodium-sulfide solution. The effects of temperature, potential, and time were examined. The index of susceptibility was defined as the anodic charge per square centimeter of the surface in 0.01 M Na2S at 37°C and 0.0 V saturated calomel electrode (SCE). The solution must be deaerated to prevent the loss of S2− ions, and the test procedure must ensure reproducible surface conditions and avoidance of spontaneous sulfidation. A series of dental alloys was evaluated using a test period of 1.5 h. The results showed good agreement with reported clinical data.
Biological Effects of Corrosion Products from Metals
Authors: Merritt K , Brown SA
Published: December 2008

Metallic implants inserted into the body will eventually undergo some degradation by a variety of mechanisms including abrasion and corrosion. The biological effects of the material released into the tissue is a subject of much concern and investigation. We have been investigating the ability of the metallic implants upon degradation to stimulate metal sensitivity reactions, and studies have been undertaken in humans and animals to investigate the tissue response to metallic implants in the presence of metal sensitivity. It is apparent that many patients have a sensitivity to the metals in the implants and that the presence of metals in a sensitive animal or human will elicit inflammatory responses and sometimes the formation of foreign body giant cells. This may have an adverse effect on the performance of the implant with pain, swelling, and tissue necrosis at the site and, in some cases, loosening of the implant. Studies on implant site infections revealed that infection rates are altered by the presence of this tissue response.

Metal sensitivity reactions are not to the small metal ions but to a complex of metal ions and host tissue. The nature of the binding of the metal ion to tissue or cells, the distribution of the metal ion or metal complexes in the body, and the biological responses to these complexes are of concern. We have undertaken in vitro and in vivo studies on the binding of metal ions as metal salts or as corrosion products, and it is evident that metals bind mostly to albumin. The ability of these different metals to bind to red cells and white cells varies with chromium with a valence of 6+ binding most strongly to cells. The chrome from corrosion products binds strongly to cells and thus appears to be a chromium 6+.

Metal salts or corrosion products injected intramuscularly are rapidly distributed in the body with cell binding again being seen mostly with chromium 6+. Cobalt is not distributed as rapidly in the body and apparently binds to the tissue at the site of the intramuscular injection. The interaction of serum and cells with chromium on the surface of the implant may markedly effect its corrosion and the biological activity of the complexes formed. Some of the tissue and protein binding may be altered by shifts in the pH in the tissue during inflammatory responses or in infection.
Estimation of In Vivo Type 316L Stainless Steel Corrosion Rate from Blood Transport and Organ Accumulation Data
Authors: Smith GK , Black J
Published: December 2008

A model utilizing implanted Type 316L stainless steel in laboratory rabbits was developed to investigate the systemic transport and distribution of constituent iron and chromium corrosion products. Results utilizing flameless atomic absorption spectrophotometry indicate that levels of circulating iron and chromium in the blood-transport compartment reflect the implanted surface area of Type 316L stainless steel. A similar positive correlation was found between implanted Type 316L stainless steel surface area and liver (reticuloendothelial) accumulations of iron and chromium. The kidney, having no reticuloendothelial capacity, demonstrated no constituent element accumulations.

Approximate corrosion rates of Type 316L stainless steel were calculated by: (1) superimposing the observed plasma iron elevations on transport compartment size and plasma iron kinetics, and by (2) evaluating storage site accumulations of iron and chromium over time. All calculations are consistent with Type 316L stainless steel's reported corrosion rate as measured by more precise in vitro and in vivo analytical techniques (20 to 300 ng/cm2/day).

Although the clinical significance of these findings is presently indeterminable, it is clear that the biological system as a whole must be considered when assessing the longterm biocompatibility of implanted Type 316L stainless steel.
Host Reaction to Silicone Implants: A Long-Term Clinical and Histopathological Study
Authors: Swanson AB , Kent Maupin B , Nalbandian RM , deGroot Swanson G
Published: December 2008

Host tolerance to implant materials has been evaluated since the initiation of a research project for use of silicone for joint replacement since 1962. Both the local and systemic tolerance to implants was analyzed in biomechanical and biological studies in laboratory animals and humans. Both soft tissues and bone reactions have been evaluated by pathological and radiological studies. The early studies included implant procedures on 25 dogs. Three dogs were sacrificed after 10 years and complete autopsies were performed to evaluate the local and systemic biocompatibility. End-bearing amputation stump implants were inserted in two of these dogs and the third animal had implant capping of ribs at the costovertebral junction and a silicone active tendon in a hind leg. A smooth-surfaced fibrous capsule surrounded the implants with no evidence of bone absorption or bursa formation; small silicone wear particles were well tolerated by giant cells. A complete organ and reticuloendothelial system review failed to show evidence of metastases of silicone particles. A similar, excellent biocompatibility of silicone implants was demonstrated in the autopsy of a rheumatoid patient who had silicone implants in both hands, radial heads, and feet starting 12 years before death. A few, small, well-tolerated silicone particles were seen in giant cells in the synovium with minimal inflammatory cells and no focal necrosis. A small amount of well-tolerated silicone particles were present in giant cells in an axillary node. A thorough organ study failed to show distant silicone particle metastases. These studies showed the good biocompatibility of silicone implants.
In Vivo Degradation of a Polyurethane: Preclinical Studies
Authors: Parins DJ , McCoy KD , Horvath N , Olson RW
Published: December 2008

In vivo investigation of a polyether polyurethane for possible use as pacing lead insulation material revealed surface degradation in the form of numerous cracks. The cracking phenomenon appeared to be stress related. Cracks were observed after three months implant time in rats and affected greater surface area with increasing implant time.

Toxicological investigation of the host animals revealed no adverse effects attributable to the polymer cracking phenomenon.

Examination by scanning electron microscopy revealed cracking that raised concerns about the integrity of thin-walled pacing leads. Ambient controls and in vitro specimens did not develop surface cracks. Surface cracking was independent of weight averaged molecular weight (Mw) and was observed on all tested samples, the Mw ranged from 255 000 through 636 000. No significant change in Mw after implant could be detected.

Surface degradation of this polyurethane was reproducible in controlled animal studies.
Degradation and Wear of Ultra-High-Molecular-Weight Polyethylene
Authors: McKellop HA , Clarke IC
Published: December 2008

A ten-station joint simulator was used to examine the wear properties of 18 total hip prostheses. The wear rates of polyethylene acetabular cups bearing against titanium alloy femoral components were compared to those with either Type 316 stainless steel or cobalt-chrome alloy controls. Three titanium alloy prostheses and three controls were tested from three different manufacturers. Wear was determined by weighing the acetabular cups, using soak-controls to correct for fluid absorption. One million cycles were run under physiological loading, with bovine serum lubrication. For two of the three sets of prostheses, the titanium alloy generated higher mean polyethylene wear rates than the controls. However, the difference was not statistically significant (p > 0.05). The titanium alloy components showed more extensive surface abrasion than either the stainless steel or cobalt-chrome components. This appeared to be an artifact of joint simulator testing, since such extensive surface abrasion was not observed on numerous prostheses removed from patients after several years of use. The third set of titanium alloy prostheses, which had been subjected to a special surface hardening process, showed virtually no surface abrasion, and the mean polyethylene wear rate was identical to that with the cobaltchrome controls. All of the polyethylene wear rates were in the range generally reported for total hip prostheses in clinical use.
Retrieval Analyses of Total Joint Components from the University of Missouri-Kansas City School of Medicine Implant Retrieval Program
Authors: Hood RW
Published: December 2008

The retrieval analyses of orthopaedic implants gathered at revision surgery or at autopsy provide much needed data as to the performance of such implants in vivo. This paper details the organization of such a retrieval program in a university medical center. The primary objective of this program is to identify specific implant design and material problem areas. Since such a variation of designs and materials of total joint implants exists, special emphasis is placed on these retrieval analyses. Femoral stem fracture in older total hip designs has been observed. Surface failure and cold flow of the ultrahigh molecular weight polyethylene has been also found, particularly in some total knee designs.
Pluralistic Medical Device Risk Management: Standards, Regulation, and Litigation
Authors: Piehler HR
Published: December 2008

The operation of the currently existing institutions and processes for managing risks associated with the use of medical devices are reviewed and analyzed. Questions addressed include the definition(s) of device failure, the establishment of acceptable failure rates, and the selection of the parties to be involved in these risk-management processes, both prospectively and retrospectively. Currently perceived difficulties associated with the unilateral risk-management activities of both the FDA regulatory apparatus plus the product liability and medical malpractice litigation systems are described. A pluralistic risk-management approach based upon marketplace incentives is proposed. This marketplace-in-centive approach encourages the development and use of performance standards both to enhance benefits to patients and to reduce the adversarial tension between the FDA and the private sector as well.
Scientific Considerations in the Legislative Arena
Authors: Durbin R
Published: December 2008

I am very happy to talk about a subject that I have become a lot more familiar with over the past year and a half since I entered Congress, the role that scientific information plays in political decision-making.
Scientific Considerations in the International Arena
Authors: Lee CM
Published: December 2008

The last decade has seen the introduction of significant pieces of national legislation to control the use of chemicals and ensure their human and environmental safety. In the last five years the Organization for Economic Co-operation and Development (OECD) Program on Chemicals has achieved significant international harmonization of the principles and many of the methods for assessing the potential hazard of chemicals to man and the environment. The mutual acceptance of data between nations using these harmonized methods has also been agreed and will contribute to the avoidance of nontariff barriers to trade and the unnecessary duplication of effort. Despite these achievements, however, the scientific and legislative communities have yet to learn how to communicate fully and effectively. The development of standard methods remains too slow, and too little attention is paid to the validation of methods, which is hindering the international harmonization process. Considerable scope remains for the improvement of the mechanism by which international harmonization is achieved. This should include establishing closer links between the standardization organizations and those developing legislation and deriving an approach that will avoid the premature introduction of research results.
Research Needs for Rapid Assessments of Chronic Toxicity
Authors: Birge WJ , Black JA
Published: December 2008

Chronicity frequently is the most important and sensitive factor in determining the impact of toxicant stress on aquatic biota. However, chronic values are often unavailable or inadequate to provide decisive judgments in hazard assessment. Time and cost constraints involved in generating traditional chronic data also pose equally important problems in basic toxicological research. In assessing rapid means for estimating chronicity, attention is given to predictive models based on structure-activity relationships, extrapolations from acute toxicity data, and use of short chronic (mini-chronic) tests. High priority is placed on further development and evaluation of mini-chronic tests, which have been used successfully to characterize single compounds and complex effluents, evaluate effluent treatability, and determine the effects of point-source discharges on natural receiving waters. Methods most commonly used have involved (1) a five to eight-day fish embryo-larval test, (2) a seven-day cladoceran test, and (3) a seven-day fathead minnow larval growth test. General research needs are summarized as follows: (1) Evaluation of short toxicity tests presently available. This should include accuracy and reproducibility of endpoint determinations and statistical correlations between minichronic data and results obtained using traditional chronic and embryo-larval tests. (2) Design of multiple species tests, in-stream flow-through tests, and other short-term test procedures for estimating chronic effects of complex effluents and single compounds. (3) Determination of the effects of laboratory and field conditions, general water quality characteristics, and selection of animal species on results of mini-chronic tests. (4) Consideration of nonorganismal tests or mathematical models that may be used to estimate chronicity. Such research may include enzyme inhibition tests, QSAR-based modeling, and extrapolations based on acute toxicity data. (5) Investigations of the physiological and biochemical mechanisms involved in acute and chronic toxicity. Analyzing the accuracy and extrapolative value of acute, mini-chronic, and chronic tests data depends in large measure on understanding the pharmacodynamics of toxicants affecting aqautic biota.
Biological Effects of Continuous and Intermittent Dosing of Outdoor Experimental Streams with Chlorpyrifos
Authors: Eaton J , Arthur J , Hermanutz R , Kiefer R , Mueller L , Anderson R , Erickson R , Nordling B , Rogers J , Pritchard H
Published: December 2008

Two outdoor experimental streams fed by water pumped from the Mississippi River were dosed with the organophosphorus pesticide chlorpyrifos (the active ingredient of Dursban® and Lorsban 4E® insecticides) for 100 days, and the responses of individual species and communities compared to those of a control stream. Chlorpyrifos was continuously metered into one stream whereas the other received 8 biweekly additions, each lasting 24 h, at 14 times the concentration in the continuously dosed stream. Therefore, nearly equal amounts of pesticide were introduced into each stream during the experiment. The biological study area of each stream was approximately 245 m long, contained a naturally colonizing plant and invertebrate assemblage, and was stocked with fathead minnows and bluegills. Measured system characteristics included macroinvertebrate drift and riffle benthos composition; fish survival, growth, reproduction, food habits, tissue residues, and AChE inhibition; and system functional process indicators (P/R ratios, biodegradation, nitrate and dissolved organic carbon [DOC] concentrations, and bacterial growth and heterotrophic activity).

The macroinvertebrate communities reacted similarly in the continuously and pulse-dosed streams. Species diversity decreased by equal amounts and was still decreasing at the end of the test. Crippling of fathead minnows and reversible acute toxicity symptoms (lethargy, tetany when startled) in bluegills were observed only in the pulse-dosed stream. Fish survived, reproduced, and grew equally well in all streams. There seemed to be good agreement between laboratory and field effect concentrations for fish and invertebrates. Functional process indices, with the possible exception of biodegradation, appeared unaffected and considerably less sensitive than other characteristics measured. The results of the project are discussed in relation to lab to field extrapolation and the need for further testing.
A New Approach for Regulating Iron in Water Quality Standards
Authors: Loeffelman PH , Van Hassel JH , Arnold TE , Hendricks JC
Published: December 2008

An extensive literature review, toxicity tests, and five months of field measurements of ferrous and total iron were undertaken. Published field data and analytical procedures are scarce for ferrous iron; few useful toxicity data are available for any of the forms of iron. Studies demonstrated that total iron concentrations now limited to 1 mg/L in many U.S. water quality standards need to be far over 1 mg/L to adversely affect Pimephales promelas and Salmo gairdneri compared to the much lower concentrations of bathophenathroline (BPA) reactive ferrous iron required for similar effects on these two species. For most freshwater bodies, regulating only this ferrous iron form should be considered for protecting aquatic life uses.
Brood Size and Neonate Weight of Daphnia magna Produced by Nine Diets
Authors: Cowgill UM , Hopkins DL , Applegath SL , Takahashi IT , Brooks SD , Milazzo DP
Published: December 2008

The purpose of this study was to discover which of nine diets would produce the largest mean brood size in Daphnia magna. Two media, one inorganic and one organic, were employed to culture three green algae: Selenastrum capricornutum, Ankistrodesmus convolutus, and Chlamydomonas reinhardtii. In addition to single algal foods, mixtures of algae were also employed. These consisted of S. capricornutum and C. reinhardtii, which were fed in varying quantities. A synthetic diet of fish chow and alfalfa served as a control. All algal diets were bacteria-free.

Neonates were acclimatized in autoclaved Lake Huron water and reared on one of the nine diets for five weeks. Demographic studies were carried out on the progeny of these acclimatized adults. First broods began to arrive after seven days. Thereafter, every other day, neonates were collected, counted, and weighed. These data presented in this study are based on 49 982 neonates.

Daphnia magna consuming algae reared on inorganic medium were less productive than those consuming algae reared on organic medium. The largest mean brood size was obtained from the mixed algal diet reared on the organic medium while the smallest mean brood size was produced by the synthetic diet. Large broods generally consisted of lighter individuals (10.8 μg per neonate) than those produced in smaller broods (20 μg per neonate). The evolutionary significance of this observation, as well as its effect on chronic life cycle studies, is discussed.
Effects of Triethylene Glycol on Mysidopsis bahia (Crustacea: Mysidacea) and Menidia peninsulae (Pisces: Atherinidae)
Authors: Montgomery RM , Forester J , D'Asaro CN
Published: December 2008

Chronic effects of triethylene glycol (TEG), a chemical frequently used as a carrier-solvent in toxicity tests, were investigated in a 23-day life-cycle toxicity test with a mysid (Mysidopsis bahia) and in a 28-day early life-stage toxicity test with the tidewater silverside (Menidia peninsulae). Test organisms were exposed to the same range of concentrations: seawater control, 3.2, 10, 32, 100, 320, and 1000 mg/L. Effects, if any, were measured by survival and reproduction for the mysids and survival and growth for the silversides. We concluded that no direct adverse effect should be expected as a result of using TEG at concentrations as high as 100 000 times (mysids) and 360 times (tidewater silversides) those recommended in ASTM drafts of standard practices (≤0.01 μL/L in Mysidopsis bahia life-cycle tests and ≤0.01 μL/L in tests with early life-stages of Menidia peninsulae) and that either a seawater or a TEG control may not be necessary.
Toxicity of Aqueous Extracts of Natural and Synthetic Oils to Three Species of Lemna
Authors: King JM , Coley KS
Published: December 2008

This study was designed to determine the acute toxicity of natural and synthetic oils to three species of Lemna. The major objectives were to determine if members of this genus can be efficiently used as bioassay organisms and if their growth responses to these oils were similar to those reported for algae. The experimental approach involved exposure of L. gibba, L. minor, and L. perpusilla under standard laboratory conditions to two crude oils, a fuel oil, and two coal-liquefaction products. Growth was monitored as changes in frond numbers. The results of this study showed that the coal-liquefaction products had a greater acute toxicity than the natural oils to the three species, which were similar to results obtained with algae. Also, the three species proved to be efficient and effective bioassay organisms.
Comparison of Techniques for Evaluating the Effect of Cadmium on Pseudomas Fluorescens
Authors: Seyfried PL , Horgan CBL
Published: December 2008

Three techniques were compared in a study of the effect of cadmium on an aquatic strain of Pseudomonas fluorescens. The methods used were (1) direct microscopic counts using epifluorescence and formazan detection, (2) determination of colonyforming units, and (3) determination of intracellular adenosine triphosphate (ATP) using a firefly luciferase bioluminescent assay. Results of the plate count and ATP determinations demonstrated that P. fluorescens was stressed after exposure to 10-, 25-, 50-, and 100-ppm cadmium. The organisms recovered following treatment; however, only the ATP bioassay data indicated that there might be bacterial recovery at 12 h after the addition of 100-ppm cadmium. The acridine orange 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chlorine (INT) formazan reduction technique did not produce results that could be readily interpreted. The bacteria tended to clump together, and cells that had been exposed to 100-ppm cadmium generally did not fluoresce. In addition, it was not possible to detect formazan deposits in any of the cadmium-treated cells. Compared to the plate count procedure and the acridine orange INT-formazan reduction technique, the intracellular ATP assay appeared to be a more accurate method of determining the viability of P. fluorescens cells following cadmium treatment.
Measuring Fish Lengths from Instant Photographs Using a Digitizing Tablet and Minicomputer
Authors: Sauter S , Harrison JL
Published: December 2008

A modification of photographic techniques for measurement of fish lengths has been developed, which uses instant photography and a digitizing tablet with a minicomputer. Instant photography allows print inspection while live fish are retained and “retakes” of poor quality photographs can be made. A photographic record of test animals is obtained, and fish may then be measured from the photographs at any convenient time. The digitizing tablet decreases time for fish measurement from photographs and maintains or improves accuracy over manual techniques. Raw data are entered directly into the minicomputer, which is programmed to perform summary statistics after all groups are measured. Summary statistics and raw data are printed to a prescribed format by the computer. The elimination of manual data entry and subsequent data validation will result in a substantial savings in time.
Advantages of Using Regression Analysis to Calculate Results of Chronic Toxicity Tests
Authors: Stephan CE , Rogers JW
Published: December 2008

Although results of most chronic toxicity tests have been calculated using hypothesis testing to detect statistically significant differences from the control, calculation of results using regression analysis offers several major advantages. By deriving an equation for the concentration-effect relationship, regression analysis allows estimation of the concentration corresponding to a specified amount of an adverse effect or estimation of the amount of effect corresponding to a specified concentration. In addition, whereas the number of replicates, agreement between replicates, and selection of α (the acceptable level of Type 1 error) have no impact on the estimate of the endpoint concentration calculated using regression analysis, they have a great impact on decisions concerning whether tested concentrations caused statistically significant differences. Further, use of regression analysis emphasizes the necessity of considering the biological importance of the adverse effects observed in toxicity tests. By using hypothesis testing, aquatic toxicologists have been able to avoid this difficult, important question by presenting results in terms of a variable “statistically significant difference.”
Environmental Mobility of Dioxins
Authors: Freeman RA , Schroy JM
Published: December 2008

A model has been developed to describe the vapor phase transport of low volatility organic chemicals in a soil column. The mathematical model finds the rate of vapor transport by solving the dynamic material and energy balance around a soil column. The model is used to make predictions on the transport of 2,3,7,8 tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) at the Times Beach, MO site. The model predicts that 70% of the initial dioxin mass vaporized in the first year after being sprayed onto the roads at Times Beach. In addition the model predicts that most of the transport occurs during the summer months.
Corrosion Test Loop
Authors: Yau T-L , Webster RT
Published: December 2008

In order to study the corrosion of zirconium under heat-transfer conditions, a corrosion test loop has been set up at Teledyne Wah Chang Albany. The major components of this test loop are a 37.85-L (10-gal) tank, a zirconium centrifugal pump, a heat-transfer heater, a vertical single-tube heat exchanger, and monitors for temperature, pressure, and flow speed at critical areas. Specimens were 0.9-m (3-ft) long tubes and wires, which were and were not subjected to a heat flux, respectively.

Tests of zirconium versus 50% sulfuric acid were conducted. Test results indicate that the effect of heat flux on zirconium in 50% sulfuric acid at about 160°C (330°F) is negligible. However, acid concentration may change in the process because of vaporization, imperfect sealing, condensation, and so forth. When the acid becomes too strong, zirconium will be susceptible to localized corrosion.
Corrosion of a Mild Steel in Distilled Water and Chloride Solutions: Development of a Test Method
Authors: Francis PE , Mercer AD
Published: December 2008

Mild steel is the most common structural material and is used in a wide range of environments. However, there are few systematic data on the effects of operating parameters on corrosion behavior in immersed conditions. To obtain such data, a suitable test method is required in which parameters affecting the corrosion process are carefully controlled.

Dissolution of borosilicate glass vessels in water at temperatures above 60°C was shown to lower significantly the corrosion rate of steel in distilled water. The method of aerating the solution was also important. A new test apparatus is described in which the above problems have been overcome and other parameters are capable of more precise control.

Some data obtained with the new test cell are given to validate the design. The data demonstrate the effect of dissolved oxygen on the corrosion of steel in distilled and chloride-containing water at temperatures up to 90°C.
Electrochemical Methods for Evaluating Corrosion Inhibitors in Strong Acid Systems
Authors: Dean SW , Woodroof RA , Nichols J
Published: December 2008

Electrochemical techniques have been evaluated for determining the performance of corrosion inhibitors in oil well acidizing solutions. Tests have been made with a variety of corrosion inhibitor blends in hydrochloric acid over a range of concentrations using carbon steel electrodes. Two different scan rates were evaluated. Longer term immersion tests were made with the same inhibitors to evaluate the degree of inhibition and development of pitting.

Reverse scan polarization was found to produce anodic hysteresis loops similar to what is observed with passive alloys in chloride containing environments. A number of parameters from the reverse scan polarization hysteresis loop have been examined for correlation with pitting tendency. The return potential anodic corrosion rate appears to have merit for showing pitting tendency. The pitting tendency seems to be most severe when the inhibitor is at a relatively low concentration. The poor correlation seen between the 16-h mass loss corrosion rates and the electrochemical corrosion rate estimates is probably caused by inhibitor exhaustion in the mass loss results. Polarization scan rate effects also showed that inhibitor adsorption kinetics affected the anodic polarization parameters.
Crevice and Pitting Corrosion Tests for Stainless Steels: A Comparison of Short-Term Tests with Longer Exposures
Authors: Hubbell M , Price C , Heidersbach R
Published: December 2008

Several methods for determining the “protection potential” of stainless steels have been reported in the literature. As most commonly defined, this potential is the potential below which metals will not corrode by pitting or crevice corrosion. This report presents a discussion on how the protection potential, if it were accurately known, could be utilized to control corrosion of stainless steels. The results of four different experimental methods for determining the protection potential for American Iron and Steel Institute 304 (Unified Numbering System [UNS] S30400) stainless steel are presented and compared.
A Technique for Characterizing Crevice Corrosion Under Hydrothermal Conditions
Authors: Jain H , Ahn T-M , Soo P
Published: December 2008

A technique was developed to monitor crevice corrosion of Grade-12 titanium in a high magnesium synthetic brine under hydrothermal conditions. The current between the cathode and anode and the potential of the whole crevice assembly provide information on the various stages of corrosion. Occasionally, the decoupled potential of the cathode and anode are measured to give supporting information about the crevice conditions. A parallel test is run on a specimen that has small wells to collect crevice solution whose pH is determined at room temperature.

The current/potential results show that the crevice corrosion incubation period for a Grade-12 titanium crevice formed between two Teflon® plates is approximately two days at 150°C. Optical and scanning electron microscopy (SEM) observations show that the corrosion starts as isolated pitting that spreads along the surface as shallow pits. The corrosion conditions change significantly as the titanium oxide corrosion product fills the crevice, and the rate of corrosion may be greatly reduced after several days. The rate of crevice corrosion of commercial purity (Grade-2) titanium under similar conditions is approximately three orders of magnitude higher. In this case, active dissolution of metal starts during the initial heating of the autoclave, and the incubation period is negligible.
MTI Corrosion Tests for Iron- and Nickel-Base Corrosion Resistance Alloys
Authors: Treseder RS , Kachik EA
Published: December 2008

The Materials Technology Institute (MTI) of the Chemical Process Industries, Inc. has selected a series of laboratory corrosion tests to provide guideline information on new wrought iron- and nickel-base corrosion resistant alloys. Data obtained from these procedures are expected to provide the materials engineer with a reasonable assessment of the probable utility of a new alloy in a variety of environments or corrosion conditions and thus facilitate the commercial usage of such alloys. The test procedures are based essentially on ASTM methods. Test procedures are specified in sufficient detail to insure comparable data being obtained by different laboratories. Two basic concepts are used: (1) in each test a critical test factor is selected as the criterion for corrosion resistance of the alloys and (2) a control alloy is selected for each test, specimens of the control alloy being supplied by MTI. There are five test procedures: one for general corrosion, two for crevice corrosion, and two for stress corrosion cracking.
Cascade Defect Production and Irradiation Enhanced Diffusion in Cu3Au
Authors: Kirk MA , Funk LL
Published: December 2008

By using the ordering alloy Cu3Au and measuring resistivity changes during and following fast-neutron irradiations under well-controlled conditions in the Radiation Effects Facility at the Intense Pulsed Neutron Source at Argonne National Laboratory, we have studied cascade defect production and irradiation enhanced diffusion between 10 and 460 K. Ordering and disordering rates were measured as functions of irradiation temperature, neutron dose, neutron dose rate, time following cessation of flux, and step annealing. Free and clustered vacancy production was observed. The temperature dependence of the production of total migrating vacancy concentrations was determined. Vacancy sink production was linear with neutron dose and is compared with recent transmission electron microscopy experiments on the production of dislocation loops in this alloy. Time dependent and quasi-steady state vacancy concentrations were measured and compared with solutions of reaction rate equations for irradiation enhanced diffusion. The influence of recombination of vacancies with interstitials is observed at low sink concentrations (low neutron doses).
The Collapse of Defect Cascades to Dislocation Loops During Self-Ion Irradiations of Iron, Nickel, and Copper at 30, 300, and 600 K
Authors: Kirk MA , Robertson IM , Vetrano JS , Jenkins ML , Funk LL
Published: December 2008

The formation of dislocation loops by self-ion irradiations of iron, nickel, and copper has been studied in situ in the Argonne National Laboratory (ANL) high-voltage electron microscope (HVEM) as functions of ion dose and irradiation temperature. At low doses (≤1012 ions/cm2) at room temperature individual cascades were observed to collapse to vacancy dislocation loops in copper with high probability, in nickel with lower probability, and in iron with zero probability. Cascade collapse was observed at low doses at 30 K in copper and nickel, but at rates less than their respective rates at room temperature. A loop formation rate for nickel at 600 K is also reported. At higher doses (> 1013 ions/cm2) where overlap of cascades becomes significant, loops were first observed in iron and with a supra-linear buildup with dose. Also at higher doses a decrease in loop production rate in copper and nickel was observed because of loop coalescence. The material and temperature dependence of cascade collapse probabilities is suggested to be related to thermal spike mechanisms during the cascade formation lifetime.