40 CFR 797.1300 - Daphnid acute toxicity test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... continuous exposure over a specified period of time. In this guideline, the effect measured is immobilization... at a point in time, or passing through the test chamber during a specific interval. (7) Static system..., daphnids which have been cultured and acclimated in accordance with the test design are randomly placed...

40 CFR 797.1300 - Daphnid acute toxicity test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... continuous exposure over a specified period of time. In this guideline, the effect measured is immobilization... at a point in time, or passing through the test chamber during a specific interval. (7) Static system..., daphnids which have been cultured and acclimated in accordance with the test design are randomly placed...

Static renewal tests using Pimephales promelas (fathead minnows) and Ceriodaphnia dubia (daphnids). Clinch River-Environmental Restoration Program (CR-ERP) study, ambient water toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1994-12-31

Clinch River-Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a study during the week of January 25--February 1, 1994. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected from Clinch River Mile 9.0, Poplar Creek Mile 1.0, and Poplar Creek Mile 2.9 on January 24, 26, and 28. Samples were partitioned and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival or growth) to fathead minnows; however, toxicity to daphnids wasmore » demonstrated in undiluted samples from Poplar Creek Mile 1.0 in testing conducted by TVA based on hypothesis testing of data. Point estimation (IC{sub 25}) analysis of the data, however, showed no toxicity in PCM 1.0 samples. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; Meter calibrations; and Reference toxicant test information.« less

Toxicity of used drilling fluids to mysids (Mysidopsis bahia)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaetz, C.T.; Montgomery, R.; Duke, T.W.

1986-01-01

Static, acute toxicity tests were conducted with mysids (Mysidopsis bahia) and 11 used drilling fluids (also called drilling muds) obtained from active drilling platforms in the Gulf of Mexico, U.S.A. Each whole mud was tested, along with three phases of each mud: a liquid phase with all particulate materials removed; a suspended particulate phase composed of soluble and lighter particulate fractions; and a solid phase composed mainly of drill cuttings and rapidly settling particulates. These muds represented seven of the eight generic mud types described by the U.S. Environmental Protection Agency for use on the U.S. Outer Continental Shelf. Themore » toxicity of the 11 muds tested was apparently enhanced by the presence of aromatics. Furthermore, one mud tested repeatedly showed loss of toxicity with time, possibly from volatilization of aromatic fractions. The data demonstrated that aromatics in the drilling fluids affected their toxicity to M. bahia.« less

Static renewal tests using Anodonta imbecillis (freshwater mussels). Anodonta imbecillis QA test 4, Clinch River-Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1994-12-31

Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organisms quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected September 8 from Poplar Creek Miles 6.0 and 1.0 was conducted September 13--22, 1994. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments. Attachments to this report include: Chain of custody form -- original; Toxicity testmore » bench sheets; Ammonia analysis request and results; and Meter calibration log sheets.« less

Static renewal tests using Anodonta imbecillis (freshwater mussels). Anodonta imbecillis copper sulfate reference toxicant/food test, Clinch River-Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1993-12-31

Reference toxicant testing using juvenile freshwater mussels was conducted as part of the CR-ERP biomonitoring study of Clinch River sediments to assess the sensitivity of test organisms and the overall performance of the test. Tests were conducted using moderately hard synthetic water spiked with known concentrations of copper as copper sulfate. Two different foods, phytoplankton and YCT-Selenastrum (YCT-S), were tested in side by side tests to compare food quality. Toxicity testing of copper sulfate reference toxicant was conducted from July 6--15, 1993. The organisms used for testing were juvenile fresh-water mussels (Anodonta imbecillis). Although significant reduction in growth, compared tomore » the phytoplankton control, was seen in all treatments, including the YCT-S Control, the consequence of this observation has not been established. Ninety-day testing of juvenile mussels exhibited large variations in growth within treatment and replicate groups. Attachments to this report include: Toxicity test bench sheets and statistical analyses; and Copper analysis request and results.« less

Static renewal tests using Anodonta imbecillis (freshwater mussels). Anodonta imbecillis QA test 1, Clinch River-Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1993-12-31

Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA and CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments to provide a quality assurance mechanism for test organism quality and overall performance of the test. In addition, testing included procedures comparing daily renewal versus non-renewal of test sediments. Testing of sediment samples collected July 15 from Poplar Creek Miles 6.0 and 5.1 was conducted from July 21--30, 1993. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments. Sidemore » by side testing of sediments with daily sediment renewal and no sediment renewal showed no differences between methods. This may be due to the absence of toxicity in both samples and may not reflect true differences between the two methods for toxic sediment. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; and Ammonia analysis request and results.« less

Handbook of acute toxicity of chemicals to fish and aquatic invertebrates : summaries of toxicity tests conducted at Columbia National Fisheries Research Laboratory, 1965-78

USGS Publications Warehouse

Johnson, W. Waynon; Finley, Mack T.

1980-01-01

Acute toxicity is a major subject of research at Columbia National Fisheries Research Laboratory for evaluating the impact of toxic chemicals on fishery resources. The Laboratory has played a leading role in developing research technology for toxicity testing and data interpretation. In 1965-78, more than 400 chemicals were tested against a variety of invertebrates and fish species representative of both cold- and warm-water climates.The use of acute toxicity tests for assessing the potential hazard of chemical contaminants to aquatic organisms is well documented (Boyd 1957; Henderson et al. 1960; Sanders and Cope 1966; Macek and McAllister 1970). Static acute toxicity tests provide rapid and (within limits) reproducible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a database for determining relative toxicity of a large number of chemicals to a variety of species and for estimating acute effects of chemical spills on natural aquatic systems; they also assist in determining priority and design of additional toxicity studies.Acute toxicity tests usually provide estimates of the exposure concentration causing 50% mortality (LC50) to test organisms during a specified period of time. For certain invertebrates, the effective concentration is based on immobilization, or some other identifiable endpoint, rather than on lethality. The application of the LC50 has gained acceptance among toxicologists and is generally the most highly rated test for assessing potential adverse effects of chemical contaminants to aquatic life (Brungs and Mount 1978; American Institute for Biological Sciences 1978a).The literature contains numerous papers dealing with the acute toxicity of chemicals to freshwater organisms. However, there is a tremendous need for a concise compendium of toxicity data covering a large variety of chemicals and test species. This Handbook is a compilation of a large volume of acute toxicity data from the Columbia Laboratory and its field laboratories. It presents definitive acute toxicity data on 271 chemicals tested against a variety of freshwater invertebrates and fishes. The chemicals represent all major groups of pesticides, as well as numerous industrial chemicals. This compilation should serve as a useful database for the many agencies and organizations dealing with research and management programs concerned with the impact of chemicals on aquatic resources.The Columbia Laboratory has played a major role in developing currently used standard methodology for static acute toxicity testing. The use of standardized methodology greatly reduces variation in results. The data presented here have been carefully scrutinized to eliminate tests that failed to follow acceptable procedures. Handling of test organisms and procedures for static toxicity tests followed those described by Lennon and Walker (1964) and Macek and McAllister (1970), and conform well with those recommended by Brauhn and Schoettger (1975) and the Committee on Methods for Toxicity Tests with Aquatic Organisms (1975).The species of fish and invertebrates that were tested are listed in phylogenetic order in Tables 1 and 2. Fish were obtained from Federal and State hatcheries as either eggs or fry. Original stocks of invertebrates were collected and cultured from wild populations with no known source of contamination; these populations were replenished regularly. The invertebrates were cultured in the Laboratory by methods similar to those described by Sanders and Cope (1966).Test chemicals usually consisted of technical or analytical grade samples of known purity. Formulations of the chemicals were also tested when available. When purity of test chemicals was known, all calculated concentrations were based on percent active ingredients. Stock solutions were prepared immediately before each test, with commercial grade acetone as the carrier solvent. Occasionally, ethanol or dimethyl-formamide was substituted. Solvent concentrations did not exceed 0.5 mL/L in final dilution water.Test water (dilution water) was reconstituted from deionized water of at least 106 ohms resistivity by the addition of appropriate reagent grade chemicals (Marking 1969). Water was buffered to maintain a pH of 7.2 to 7.5, an alkalinity of 30 to 35 mg/L, and a hardness of 40 to 50 mg/L as CaCO3. Test water was mixed thoroughly and aerated before transfer into test chambers. Fish were acclimated to dilution water by gradually changing the water in acclimated tanks from 100% well water to 100% reconstituted water over a 1- to 3-day period at the desired testing temperature. Invertebrates were acclimated from well water to dilution water over a 4- to 6-h period. Toxicity tests were conducted under static conditions without aeration, and the organisms were not fed during acclimation or testing. Temperature of test solutions was maintained within ± 1°C of that required for a given test.Toxicity tests with fish were conducted in 18.9-liter (5-gal) wide-mouthed jars containing 15 liters of test solution. Fingerling fish weighing 0.2 to 1.5 g were tested at each concentration. Caution was taken not to exceed 0.8 g of test organisms per liter of solution. Duplicate test chambers were used to accommodate larger fish. Test chambers varied in size for invertebrates, depending on the species used; volume of test solution ranged from 0.25 to 4 liters. At least 10 organisms were exposed to each concentration for all definitive tests. At least six concentrations were used per toxicity test.The tests began upon initial exposure to the toxicant and continued for 96 h. Immobilization tests with invertebrates were conducted for only 48 h. The number of dead or affected organisms in each test chamber were recorded and the dead organisms were removed every 24 h; general observations on the condition of test organisms were also recorded at these times.Toxicity data were analyzed by a statistical method described by Litchfield and Wilcoxon (1949) to determine LC50 (theoretical estimate of the concentration lethal to 50% of the test animals) and 95% confidence intervals. This method is recommended by the American Public Health Association (1971) and by Sprague (1969) for determining median lethal concentrations. The procedure is easily modified for computing a single LC50 when replicate tests are performed.

Static renewal tests using Anodonta imbecillis (freshwater mussels). Anodonta imbecillis QA test 2, Clinch River-Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1993-12-31

Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organism quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected August 14 from Poplar Creek Miles 6.0 and 4.3 was conducted from August 24--September 2, 1993. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments. Attachments to this report include: Chain of custody form -- original;more » Toxicity test bench sheets and statistical analyses; and Ammonia analysis request and results.« less

Mimicking natural systems: Changes in behavior as a result of dynamic exposure to naproxen.

PubMed

Neal, Alexandra E; Moore, Paul A

2017-01-01

Animals living in aquatic habitats regularly encounter anthropogenic chemical pollution. Typically, the toxicity of a chemical toxicant is determined by the median lethal concentration (LC 50 ) through a static exposure test. However, LC 50 values and static tests do not provide an accurate representation of exposure to pollutants within natural stream systems. In their native habitats, animals experience exposure as a fluctuating concentration due to turbulent mixing, temporal variations of contamination (seasonal inputs), and contaminant input type (point vs. non-point). Research has shown that turbulent environments produce exposures with a high degree of fluctuation in frequency, duration, and intensity. In order to more effectively evaluate the effects of pollutants, we created a dynamic exposure paradigm, utilizing both flow and substrate within a small mesocosm. A commonly used pharmaceutical, naproxen, was used as the toxicant and female crayfish (Orconectes virilis) as the target organism to investigate changes in fighting behavior as a result of dynamic exposure. Crayfish underwent either a 23h long static or a dynamic exposure to naproxen. Following exposure, the target crayfish and an unexposed size matched opponent underwent a 15min fight trial. These fight trials were recorded and later analyzed using a standard ethogram. Results indicate that exposure to sublethal concentrations of naproxen, in both static and flowing conditions, negatively impact aggressive behavior. Results also indicate that a dynamic exposure paradigm has a greater negative impact on behavior than a static exposure. Turbulence and habitat structure play important roles in shaping chemical exposure. Future research should incorporate features of dynamic chemical exposure in order to form a more comprehensive image of chemical exposure and predict the resulting sublethal effects from exposure. Possible techniques for assessment include utilizing flow-through experimental set-ups in tandem with behavioral or physiological endpoints as opposed to acute toxicity. Other possibilities of assessment could involve utilizing fine-scale chemical measurements of pollutants to determine the actual concentrations animals encounter during an exposure event. Copyright © 2016 Elsevier Inc. All rights reserved.

Static renewal tests using Pimephales promelas (fathead minnows) and Ceriodaphnia dubia (daphnids). Clinch River-Environmental Restoration Program (CR-ERP) pilot study, ambient water toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1993-12-31

Clinch River-Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a pilot study during the week of April 22--29, 1993, prior to initiation of CR-ERP Phase 2 Sampling and Analysis activities. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected by TVA Field Engineering personnel from Clinch River Mile 9.0 and Poplar Creek Kilometer 1.6 on April 21, 23, and 26. Samples were split and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in nomore » toxicity (survival, growth, or reproduction) to either species in testing conducted by TVA. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; Reference toxicant test information; and Personnel training documentation.« less

Acute toxicities of toxaphene and endrin to larvae of seven species of amphibians

USGS Publications Warehouse

Hall, R.J.; Swineford, D.M.

1981-01-01

Seven species of amphibian larvae were exposed to toxaphene and endrin in a continuous-flow dosing system to determine differences in sensitivity to the two compounds, EC50 and LC50 estimates varied from those for Rana sphenocephala by no more than one order of magnitude when calculated on the basis of intended concentrations. Removal of pesticides from water by the test animals was significant and it makes interpretation of results difficult. Continuous-flow toxicity tests conflict with the adaptations of amphibian larvae for static water; use of such tests for amphibians requires further evaluation.

Toxicities of crude oils and oil-dispersant mixtures to juvenile rabbitfish, Siganus rivulatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisler, R.; Kissil, G.W.

1975-01-01

Toxicities were determined for two crude oils, one from the Persian Gulf (Iran) and one from the Sinai Peninsula (Gulf of Suez), to rabbitfish, Siganus rivulatus, an economically important species of teleost from the Red Sea. Also tested for toxicity were ST 5, a chemical oil dispersant, and oil-ST 5 mixtures in the ratio 10:1 vol/vol. Static tests conducted in small (3-liter) jars at 41 /sup 0///sub 00/ salinity and 23/sup 0/C produced LC/sub 50/ (168 h) values of 0.74 ml/liter for Iranian crude, 14.5 ml/liter for Sinai crude, and 0.010 ml/liter for ST 5; LC/sub 50/ values for oil-STmore » 5 mixtures reflected biocidal properties of ST 5 alone. Iranian oil became less toxic with increasing time in seawater over a period of 168 hours; the reverse was observed for Sinai crude. ST 5 exhibited a dramatic reduction in lethality after 2 hours in the assay medium. The most toxic component tested of Iranian crude was the lowest-boiling fraction; with Sinai crude it was the highest-boiling fraction; with ST 5 the volatile surfactant component accounted for almost all deaths. Liver enlargement in rabbitfish was linked with exposure to comparatively high concentrations of crude oil. High sublethal levels of ST 5 caused reductions in blood hematocrit. Rabbitfish survival at a given petrochemical concentration was highest at intermediate salinities of 30-50 /sup 0///sub 00/ in the salinity range tested of 20 to 60 /sup 0///sub 00/. Rabbitfish were more resistant to crudes and oil-dispersant mixtures in continuous flow bioassays conducted in large tanks than in static jar bioassays. Tank tests also suggested that mortalities were higher among toxicant-stressed fish confined 0.2 to 1.0 meters from the surface than among fish held 1.0 to 1.8 m from the surface. (auth)« less

Use of porewater extracts to identify the cause of toxicity in marine and estuarine sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douglas, W.S.

1994-12-31

Amphipod toxicity tests in the evaluation of dredged material proposed for ocean disposal has come under increased scrutiny by the regulated community in the Port of NY/NJ. In recent large-scale assessments of sediment quality in the harbor, the vast majority of locations were deemed highly contaminated when tested with Ampelisca abdita. Toxicity tests, by themselves, do not provide data regarding the cause of toxicity of these sediments. The enormous potential costs associated with most proposed alternatives to ocean disposal of dredged sediments has prompted the investigation of the causative agents of toxicity in sediments of the NY/NJ Harbor. Sediment frommore » five locations in the harbor, selected in consultation with local regulatory agencies to represent diverse potential contamination scenarios, was collected and tested for toxicity to the amphipods Ampelisca abdita, Leptocheirus plumulosus, Eohaustorius estuadus, Rhepoxynius abronius, and the mysid shrimp, Mysidopsis bahia, using 10-day static bioassays. Porewater from each of the five sediments was extracted under centrifugation and used in water-only toxicity tests with A. abdita, L. plumulosus, R. abronius, E. estuadus, M. bahia, M. beryllina, and Microtox. A Phase 1 Toxicity Identification Evaluation of the three most toxic porewater samples was conducted using several of the species tested. Results from the preliminary investigations and the ongoing TIE`s will be presented. Species selection, porewater toxicity test procedures, and Phase 1, 2, and 3 paradigms will be discussed.« less

Survival and growth of freshwater pulmonate and nonpulmonate snails in 28-day exposures to copper, ammonia, and pentachlorophenol

USGS Publications Warehouse

Besser, John M.; Dorman, Rebecca A.; Hardesty, Douglas K.; Ingersoll, Christopher G.

2016-01-01

We performed toxicity tests with two species of pulmonate snails (Lymnaea stagnalis and Physa gyrina) and four taxa of nonpulmonate snails in the family Hydrobiidae (Pyrgulopsis robusta,Taylorconcha serpenticola, Fluminicola sp., and Fontigens aldrichi). Snails were maintained in static-renewal or recirculating culture systems with adults removed periodically to isolate cohorts of offspring for toxicity testing. This method successfully produced offspring for both species of pulmonate snails and for two hydrobiid species, P. robusta and Fluminicola sp. Toxicity tests were performed for 28 days with copper, ammonia, and pentachlorophenol in hard reconstituted water with endpoints of survival and growth. Tests were started with 1-week-old L. stagnalis, 2-week-old P. gyrina, 5- to 13-week-old P. robusta and Fluminicola sp., and older juveniles and adults of several hydrobiid species. For all three chemicals, chronic toxicity values for pulmonate snails were consistently greater than those for hydrobiid snails, and hydrobiids were among the most sensitive taxa in species sensitivity distributions for all three chemicals. These results suggest that the toxicant sensitivity of nonpulmonate snails in the family Hydrobiidae would not be adequately represented by results of toxicity testing with pulmonate snails.

Long-term (30 days) toxicity of NiO nanoparticles for adult zebrafish Danio rerio

PubMed Central

Kovrižnych, Jevgenij A.; Zeljenková, Dagmar; Rollerová, Eva; Szabová, Elena

2014-01-01

Nickel oxide in the form of nanoparticles (NiO NPs) is extensively used in different industrial branches. In a test on adult zebrafish, the acute toxicity of NiO NPs was shown to be low, however longlasting contact with this compound can lead to its accumulation in the tissues and to increased toxicity. In this work we determined the 30-day toxicity of NiO NPs using a static test for zebrafish Danio rerio. We found the 30-day LC50 value to be 45.0 mg/L, LC100 (minimum concentration causing 100% mortality) was 100.0 mg/L, and LC0 (maximum concentration causing no mortality) was 6.25 mg/L for adult individuals of zebrafish. Considering a broad use of Ni in the industry, NiO NPs chronic toxicity may have a negative impact on the population of aquatic organisms and on food web dynamics in aquatic systems. PMID:26038672

Long-term (30 days) toxicity of NiO nanoparticles for adult zebrafish Danio rerio.

PubMed

Kovrižnych, Jevgenij A; Sotníková, Ružena; Zeljenková, Dagmar; Rollerová, Eva; Szabová, Elena

2014-03-01

Nickel oxide in the form of nanoparticles (NiO NPs) is extensively used in different industrial branches. In a test on adult zebrafish, the acute toxicity of NiO NPs was shown to be low, however longlasting contact with this compound can lead to its accumulation in the tissues and to increased toxicity. In this work we determined the 30-day toxicity of NiO NPs using a static test for zebrafish Danio rerio. We found the 30-day LC50 value to be 45.0 mg/L, LC100 (minimum concentration causing 100% mortality) was 100.0 mg/L, and LC0 (maximum concentration causing no mortality) was 6.25 mg/L for adult individuals of zebrafish. Considering a broad use of Ni in the industry, NiO NPs chronic toxicity may have a negative impact on the population of aquatic organisms and on food web dynamics in aquatic systems.

Accumulation, metabolism and toxicity of parathion in tadpoles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hall, R.J.

1990-04-01

Earlier work exposing tadpoles to organophosphorus pesticides indicated the great resistance of tadpoles of the bullfrog (Rana catesbeiana) to these chemicals and their surprising ability to accumulate parathion and fenthion from water. These qualities seemed to make them an ideal model with which to test a hypothesis advanced by Burke and Ferguson, who noted that parathion is more toxic to resistant mosquitofish in static water than in flowing water--a reversal of the pattern normally seen. They believed that highly toxic metabolite paraoxon was produced by the fish and that its buildup in static systems resulted in the unexpected mortality. Amphibiansmore » have been shown to produce paraoxon and to accumulate the parent compound parathion to levels that are potentially hazardous to other organisms. In the course of examining paraoxon production by tadpoles, it would also be possible to learn more about their patterns of parathion uptake and elimination. Retention of residues is also a matter of concern given the high levels observed in the earlier studies.« less

Acute aquatic toxicity and biodegradation potential of biodiesel fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haws, R.A.; Zhang, X.; Marshall, E.A.

1995-12-31

Recent studies on the biodegradation potential and aquatic toxicity of biodiesel fuels are reviewed. Biodegradation data were obtained using the shaker flask method observing the appearance of CO{sub 2} and by observing the disappearance of test substance with gas chromatography. Additional BOD{sub 5} and COD data were obtained. The results indicate the ready biodegradability of biodiesel fuels as well as the enhanced co-metabolic biodegradation of biodiesel and petroleum diesel fuel mixtures. The study examined reference diesel, neat soy oil, neat rape oil, and the methyl and ethyl esters of these vegetable oils as well as various fuel blends. Acute toxicitymore » tests on biodiesel fuels and blends were performed using Oncorhynchus mykiss (Rainbow Trout) in a static non-renewal system and in a proportional dilution flow replacement system. The study is intended to develop data on the acute aquatic toxicity of biodiesel fuels and blends under US EPA Good Laboratory Practice Standards. The test procedure is designed from the guidelines outlined in Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms and the Fish Acute Aquatic Toxicity Test guideline used to develop aquatic toxicity data for substances subject to environmental effects test regulations under TSCA. The acute aquatic toxicity is estimated by an LC50, a lethal concentration effecting mortality in 50% of the test population.« less

Acute Toxicity of Sodium Fluorescein to Ashy Pebblesnails Fluminicola fuscus

USGS Publications Warehouse

Stockton, Kelly A.; Moffitt, Christine M.; Blew, David L.; Farmer, C. Neil

2011-01-01

Water resource agencies and groundwater scientists use fluorescein dyes to trace ground water flows that supply surface waters that may contain threatened or endangered mollusk species. Since little is known of the toxicity of sodium fluorescein to mollusks, we tested the toxicity of sodium fluorescein to the ashy pebblesnail Fluminicola fuscus. The pebblesnail was selected as a surrogate test species for the threatened Bliss Rapid snail Taylorcocha serpenticola that is endemic to the Snake River and its tributaries in the Hagerman Valley, Idaho. In laboratory tests, we expose replicated groups of snails to a series of concentrations of fluorescein in a static 24 h exposure at 15 degrees C. Following the exposure, we removed snails, rinsed them, and allowed a 48 h recovery in clean water before recording mortality. We estimated 377 mg/L as the median lethal dose. Mortality to snails occurred at concentrations well above those expected in test wells during the monitoring efforts.

Assessment of diclofenac LC50 reference values in juvenile and embryonic stages of the zebrafish (Danio rerio).

PubMed

Praskova, E; Voslarova, E; Siroka, Z; Plhalova, L; Macova, S; Marsalek, P; Pistekova, V; Svobodova, Z

2011-01-01

The aim of the study was to compare the acute toxicity of diclofenac to juvenile and embryonic stages of the zebrafish (Danio rerio). Acute toxicity tests were performed on the aquarium fish Danio rerio, which is one of the model organisms most commonly used in toxicity testing. The tests were performed using a semi-static method according to OECD guideline No. 203 (Fish, acute toxicity test). Embryo toxicity tests were performed in zebrafish embryos (Danio rerio) in compliance with OECD No. 212 methodology (Fish, short-term toxicity test on embryo and sac-fry stages). The results were subjected to a probit analysis using the EKO-TOX 5.2 programme to determine 96hLC50 and 144hLC50 (median lethal concentration, 50% mortality after a 96 h or 144 h interval, respectively) values of diclofenac. The statistical significance of the difference between LC50 values in juvenile and embryonic stages of Danio rerio was tested using the Mann-Whitney non-parametric test implemented in the Unistat 5.1 programme. The LC50 mean value of diclofenac was 166.6 +/- 9.8 mg/L in juvenile Danio rerio, and 6.11 +/- 2.48 mg/L in embryonic stages of Danio rerio. The study demonstrated a statistically higher sensitivity to diclofenac (P < 0.05) in embryonic stages compared to the juvenile fish.

A new developmental toxicity test for pelagic fish using anchoveta (Engraulis ringens J.).

PubMed

Llanos-Rivera, A; Castro, L R; Silva, J; Bay-Schmith, E

2009-07-01

A series of six 96-h static bioassays were performed to validate the use of anchoveta (Engraulis ringens) embryos as test organisms for ecotoxicological studies. The standardization protocol utilized potassium dichromate (K(2)Cr(2)O(7)) as a reference toxicant and egg mortality as the endpoint. The results indicated that the mean sensitivity of anchoveta embryos to potassium dichromate was 156.1 mg L(-1) (range: 131-185 mg L(-1)). The statistical data analysis showed high homogeneity in LC50 values among bioassays (variation coefficient = 11.02%). These results demonstrated that the protocol and handling procedures implemented for the anchoveta embryo bioassays comply with international standards for intra-laboratory precision. After secondary treatment, an effluent from a modern Kraft pulp mill was tested for E. ringens embryo toxicity, finding no significant differences from the controls.

Automated Lab-on-a-Chip Technology for Fish Embryo Toxicity Tests Performed under Continuous Microperfusion (μFET).

PubMed

Zhu, Feng; Wigh, Adriana; Friedrich, Timo; Devaux, Alain; Bony, Sylvie; Nugegoda, Dayanthi; Kaslin, Jan; Wlodkowic, Donald

2015-12-15

The fish embryo toxicity (FET) biotest has gained popularity as one of the alternative approaches to acute fish toxicity tests in chemical hazard and risk assessment. Despite the importance and common acceptance of FET, it is still performed in multiwell plates and requires laborious and time-consuming manual manipulation of specimens and solutions. This work describes the design and validation of a microfluidic Lab-on-a-Chip technology for automation of the zebrafish embryo toxicity test common in aquatic ecotoxicology. The innovative device supports rapid loading and immobilization of large numbers of zebrafish embryos suspended in a continuous microfluidic perfusion as a means of toxicant delivery. Furthermore, we also present development of a customized mechatronic automation interface that includes a high-resolution USB microscope, LED cold light illumination, and miniaturized 3D printed pumping manifolds that were integrated to enable time-resolved in situ analysis of developing fish embryos. To investigate the applicability of the microfluidic FET (μFET) in toxicity testing, copper sulfate, phenol, ethanol, caffeine, nicotine, and dimethyl sulfoxide were tested as model chemical stressors. Results obtained on a chip-based system were compared with static protocols performed in microtiter plates. This work provides evidence that FET analysis performed under microperfusion opens a brand new alternative for inexpensive automation in aquatic ecotoxicology.

The toxicity of arsenic(III), chromium(VI) and zinc to groundwater copepods.

PubMed

Hose, G C; Symington, K; Lott, M J; Lategan, M J

2016-09-01

Groundwater ecosystems globally are threatened by anthropogenic contamination, yet there are few ecotoxicological data using obligate groundwater biota on which to base risk assessments. Copepods are found inhabiting aquifers of different geologies around the world and so are a useful taxon for use in ecotoxicological studies of groundwater. The aim of this study was to test the sensitivity of obligate groundwater copepods to metal contaminants (arsenic(III), chromium(VI) and zinc) in groundwater in static 96 h, 14 days and 28 days exposure tests. The copepods were variably sensitive to As, Cr and Zn, with Cr being the most toxic across all taxa. No taxon was consistently most sensitive and there was no apparent relationship between the hardness, pH and organic carbon concentration of the diluent water and the sensitivity of biota. As expected, toxicity increased with exposure period and we encourage the use of longer exposure periods in future toxicity tests with groundwater organisms to reflect the greater exposure periods likely to be associated with groundwater contamination.

Comparative acute toxicity of gallium(III), antimony(III), indium(III), cadmium(II), and copper(II) on freshwater swamp shrimp (Macrobrachium nipponense).

PubMed

Yang, Jen-Lee

2014-04-01

Acute toxicity testing were carried out the freshwater swamp shrimp, Macrobrachium nipponense, as the model animal for the semiconductor applied metals (gallium, antimony, indium, cadmium, and copper) to evaluate if the species is an suitable experimental animal of pollution in aquatic ecosystem. The static renewal test method of acute lethal concentrations determination was used, and water temperature was maintained at 24.0 ± 0.5°C. Data of individual metal obtained from acute toxicity tests were determined using probit analysis method. The median lethal concentration (96-h LC50) of gallium, antimony, indium, cadmium, and copper for M. nipponense were estimated as 2.7742, 1.9626, 6.8938, 0.0539, and 0.0313 mg/L, respectively. Comparing the toxicity tolerance of M. nipponense with other species which exposed to these metals, it is obviously that the M. nipponense is more sensitive than that of various other aquatic animals.

Static renewal tests using Anodonta imbecillis (freshwater mussels). Anodonta imbecillis QA test 3, Clinch River-Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1994-12-31

Toxicity testing of split whole sediment samples using juvenile freshwater mussels (Anodonta imbecillis) was conducted by TVA to provide a quality assurance mechanism for test organism quality and overall performance of the test being conducted by CR-ERP personnel as part of the CR-ERP biomonitoring study of Clinch River sediments. Testing of sediment samples collected May 5 from Poplar Creek Miles 6.0 and 2.9 was conducted from May 10--19, 1994. Results from this test showed no toxicity (survival effects) to fresh-water mussels during a 9-day exposure to the sediments. Attachments to this report include: Chain of custody form -- original; Toxicitymore » test bench sheets; Ammonia analysis request and results; Meter calibration log sheets; and Training documentation forms.« less

Comparative sensitivity of five species of macrophytes and six species of algae to atrazine, metribuzin, alachlor, and metolachlor

USGS Publications Warehouse

Fairchild, James F.; Ruessler, Shane; Carlson, A. Ron

1998-01-01

This study determined the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metolachlor). Toxicity tests consisted of 96-h (duckweed and algae) or 14-d (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic plants than were the acetanilide herbicides (alachlor and metolachlor). Toxicity studies ranked metribuzin > atrazine > alachlor > metolachlor in decreasing order of overall toxicity to aquatic plants. Relative sensitivities of macrophytes to these herbicides decreased in the order of Ceratophyllum > Najas > Elodea > Lemna > Myriophyllum. Relative sensitivities of algae to herbicides decreased in the order of Selenastrum > Chlorella > Chlamydomonas > Microcystis > Scenedesmus > Anabaena. Algae and macrophytes were of similar overall sensitivities to herbicides. Data indicated that Selenastrum, a commonly tested green alga, was generally more sensitive compared to other plant species. Lemna minor, a commonly tested floating vascular plant, was of intermediate sensitivity, and was fivefold less sensitive than Ceratophyllum, which was the most sensitive species tested. The results indicated that no species was consistently most sensitive, and that a suite of aquatic plant test species may be needed to perform accurate risk assessments of herbicides.

Sediment toxicity in Savannah Harbor

USGS Publications Warehouse

Winger, P.V.; Lasier, P.J.

1995-01-01

Savannah Harbor, located near the mouth of the Savannah River, Georgia and South Carolina, is impacted by industrial and municipal effluents. Potential release of contaminants stored in harbor sediments through dredging and shipping operations requires that contaminated areas be identified for proper management of the system and protection of wildlife resources. During 1991, Hyalella azteca were exposed in 10-d static-renewal toxicity tests to pore-water and solid-phase sediment samples collected from 26 sites within Savannah Harbor. Pore-water toxicity was more pronounced than that for solidphase sediment. Toxicity and reduced leaf consumption demonstrated impaired sediment quality at specific sites within Savannah Harbor and Back River. Factors responsible for the decreased sediment quality were ammonia, alkalinity, and metal concentrations (cadmium, chromium, lead, molybdenum, and nickel). Elevated concentrations of metals and toxicities in Back River sediments indicated impacts from adjacent dredge-spoil areas.

TROPICAL COLLECTOR URCHIN, TRIPNEUSTES ...

EPA Pesticide Factsheets

This document describes a fertilization method to estimate the chronic toxicity of effluents and receiving waters to the gametes of the tropical sea urchin (Tripneustes gratilla). This toxicity test measures the fertilizing capacity of sperm following a static, non-renewal 60-minute exposure and a subsequent 20-minute exposure period following the addition of eggs. The purpose of the test is to determine the concentrations of a test substance diluted in sea water that reduce fertilization of exposed gametes relative to that of the control. This method was developed to provide an assessment of the toxicity of materials discharged into the marine environment, using biota indigenous to tropical Pacific regions, including Hawaii. This method provides an assessment of the toxicity to indigenous biota of materials discharged into the tropical Pacific marine environment. The use of this method contributes to risk based determinations, and the scientific foundation they provide for regulatory criteria at the state, regional or national levels. General impacts from this contribution include improved understanding by managers and scientists of links between human activities, natural dynamics, ecological stressors and ecosystem condition.

COMPARATIVE TOXICITY OF DIURON ON SURVIVAL AND GROWTH OF PACIFIC TREEFROG, BULLFROG, RED-LEGGED FROG, AND AFRICAN CLAWED FROG EMBRYOS AND TADPOLES

EPA Science Inventory

The effects of the herbicide diuron on survival and growth of Pacific treefrog (Pseudacris regilla),bullfrog(Rana catesbeiana), red-legged frog(Rana aurora),and African clawed frog(Xenopus laevis)embryos and tadpoles were determined in static-renewal tests. P.regilla and X.laevis...

The relative toxicities of several pesticides to naiads of three species of stoneflies

USGS Publications Warehouse

Sanders, Herman O.; Cope, Oliver B.

1968-01-01

Static bioassays were conducted to determine the relative acute toxicities of some insecticides, herbicides, fungicides, a defoliant, and a molluscicide to the naiads of three species of stonef!y, Pteronarcys califomica, Pteronarcella badia, and Claassenia sabulosa. Toxic effects were measured by determination of median lethal concn (Lcoo) for 24-, 48-, and 96-hr exposures, at 15.5C. Endrin and dieldrin were the most and DDT the least toxic of the chlorinated hydrocarbon insecticides tested. Parathion was the most toxic organophosphate insecticide to P. califomica naiads, but dursban was the most toxic to P. badia and C. sabulosa naiads. Trichlorofon ( Dipterex) was the least toxic to all three species. P. badia, the species of smallest size, was the species most susceptible to most pesticides, followed in descending order of sensitivity by C. sabulosa and P. califomica. Smaller specimens of P. californica naiads were consistently more susceptible to some insecticides than larger specimens of the same species.

Green hypergolic combination: Diethylenetriamine-based fuel and hydrogen peroxide

NASA Astrophysics Data System (ADS)

Kang, Hongjae; Kwon, Sejin

2017-08-01

The present research dealt with the concept of green hypergolic combination to replace the toxic hypergolic combinations. Hydrogen peroxide was selected as a green oxidizer. A novel recipe for the non-toxic hypergolic fuel (Stock 3) was suggested. Sodium borohydride was blended into the mixture of energetic hydrocarbon solvents as an ignition source for hypergolic ignition. The main ingredient of the mixture was diethylenetriamine. By mixing some amount of tetrahydrofuran with diethylenetriamine, the mixture became more flammable and volatile. The mixture of Stock 3 fuel remained stable for four months in the lab scale storability test. Through a simple drop test, the hypergolicity of the green hypergolic combination was verified. Comparing to the toxic hypergolic combination MMH/NTO as the reference, the theoretical performance of the green hypergolic combination would be achieved about 96.7% of the equilibrium specific impulse and about 105.7% of the density specific impulse. The applicability of the green hypergolic combination was successfully confirmed through the static hot-fire tests using 500 N scale hypergolic thruster.

Acute and early life stage toxicity of industrial effluent on Japanese medaka (Oryzias latipes).

PubMed

Zha, Jinmiao; Wang, Zijian

2006-03-15

To develop the whole effluent toxicity testing methods (WET), embryo larval stage toxicity test using Japanese medaka (Oryzias latipes) was conducted to evaluate an effluent from a banknote printing plant (BPP). The method is based on acute toxicity using endpoint of 96-h larval morality and on chronic toxicity using endpoints such as the time to hatch, hatching success, deformity, growth rate, swim-up failure, accumulative mortality and sexual ratio. In test for 96-h larval mortality, LC50 (the concentration was lethal to 50% of newly hatching medaka larvae) was 72.9%. In chronic toxicity test, newly fertilized embryos (<5-h old) were exposed to 1%, 6.25%, 12.5%, 25%, 50% effluent concentrations and to 200 mug/l BPA in a 24-h static renewal system at 25+/-1 degrees C until 15 day post-hatch. The results showed that all chronic endpoints were significantly different from the control at 50% dilution (p < 0.01). Embryos began to show lesions on 4th day at higher concentrations (12.5%, 25%, 50% BPP effluent concentrations). Treatment group of 25% dilution showed delayed time to hatch. A reduction in body weight was observed at 25% dilutions for males and females, respectively. Deformities were observed in newly hatched larvae at 25% and 50% BPP effluent concentrations. At 25% dilution, sex ratio of larvae was alternated and there was feminization phenomenon. We conclude that embryo larval stage test using medaka is feasible to evaluate both acute and chronic toxicities and potential endocrine disrupting activity of industrial effluents.

Acute and chronic toxicity of copper to the euryhaline rotifer, Brachionus plicatilis ("L" strain).

PubMed

Arnold, W R; Diamond, R L; Smith, D S

2011-02-01

This article presents data from original research, intended for the use in the development of copper (Cu) criteria for the protection of estuarine and marine organisms and their uses in the United States. Two 48-h static-acute toxicity tests-one with and one without added food-and a 96-h static multigeneration life-cycle test (P1-F2 generations) were performed concurrently using the euryhaline rotifer Brachionus plicatilis ("L" strain) to develop a Cu acute-to-chronic ratio (ACR) for this species. Tests were performed at 15 g/L salinity, at 25°C, and the exposure concentrations of dissolved Cu were verified. Supplemental chemical analyses were performed and reported for the development of a Cu-saltwater biotic ligand model (BLM). Supplemental analyses included alkalinity, calcium, chloride, dissolved organic carbon (DOC), hardness, magnesium, potassium, sodium, and temperature. The acute toxicity test measurement end points were the dissolved Cu median lethal concentration (LC₅₀) values based on rotifer survival. The chronic measurement end points were the dissolved Cu no-observed-effect concentration (NOEC), lowest-observed-effect concentration (LOEC), EC₂₅, EC₂₀, and EC₁₀ based on the intrinsic rate of rotifer population increase (r). The 48-h LC₅₀(Fed), 48-h LC₅₀(Unfed), 96-h NOEC, 96-h LOEC, EC₂₅, EC₂₀, and EC₁₀ were 20.8, 13.4, 6.1, 10.3, 11.7, 10.9, and 8.8 μg Cu/L, respectively. The ACRs were calculated as ratios of each 48-h LC₅₀ value [fed and unfed) and each of the 96-h chronic values (ChV; geometric mean of NOEC and LOEC)], EC₁₀, EC₂₀, and EC₂₅. The ACRs ranged from 1.15 to 2.63.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arntzen, Evan V.; Hand, Kristine D.; Carter, Kathleen M.

At the request of the U.S. Army Corps of Engineers (USACE; Portland District), Pacific Northwest National Laboratory (PNNL) undertook a project in 2006 to look further into issues of total dissolved gas (TDG) supersaturation in the lower Columbia River downstream of Bonneville Dam. In FY 2008, the third year of the project, PNNL conducted field monitoring and laboratory toxicity testing to both verify results from 2007 and answer some additional questions about how salmonid sac fry respond to elevated TDG in the field and the laboratory. For FY 2008, three objectives were 1) to repeat the 2006-2007 field effort tomore » collect empirical data on TDG from the Ives Island and Multnomah Falls study sites; 2) to repeat the static laboratory toxicity tests on hatchery chum salmon fry to verify 2007 results and to expose wild chum salmon fry to incremental increases in TDG, above those of the static test, until external symptoms of gas bubble disease were clearly present; and 3) to assess physiological responses to TDG levels in wild chum salmon sac fry incubating below Bonneville Dam during spill operations. This report summarizes the tasks conducted and results obtained in pursuit of the three objectives. Chapter 1 discusses the field monitoring, Chapter 2 reports the findings of the laboratory toxicity tests, and Chapter 3 describes the field-sampling task. Each chapter contains an objective-specific introduction, description of the study site and methods, results of research, and discussion of findings. Literature cited throughout this report is listed in Chapter 4. Additional details on the monitoring methodology and results are provided in Appendices A and B included on the compact disc bound inside the back cover of the printed version of this report.« less

Toxicity of the mosquito control pesticide Scourge to adult and larval grass shrimp (Palaemonetes pugio).

PubMed

Key, Peter; DeLorenzo, Marie; Gross, Kristen; Chung, Katy; Clum, Allan

2005-01-01

This study investigated the toxicity of various concentrations of technical resmethrin and Scourge on adult and larval Palaemonetes pugio, a common grass shrimp species. Two types of tests were conducted for each of the resmethrin formulations using adult and larval grass shrimp life stages, a 96-h static renewal aqueous test without sediment, and a 24-h static nonrenewal aqueous test with sediment. For resmethrin, the 96-h aqueous LC50 value for adult shrimp was 0.53 microg/L (95% confidence interval (CI): 0.46-0.60 microg/L), and for larval shrimp was 0.35 microg/L (95% CI: 0.28-0.42 microg/L). In the presence of sediment, technical resmethrin produced a 24-h LC50 value for adult shrimp of 5.44 microg/L (95% CI: 4.52-6.55 microg/L), and for larval shrimp of 2.15 microg/L (95% CI: 1.35-3.43 microg/L). For Scourge, the 96-h aqueous LC50 for adult shrimp was 2.08 microg/L (95% CI: 1.70-2.54 microg/L), and for larval shrimp was 0.36 microg/L (95% CI: 0.24-0.55 microg/L). The 24-h sediment test yielded an LC50 value of 16.12 microg/L (95% CI: 14.79-17.57 microg/L) for adult shrimp, and 14.16 microg/L (95% CI: 12.21-16.43 microg/L) for larvae. Adjusted LC50 values to reflect the 18% resmethrin concentration in Scourge are 0.37 microg/L (adult), 0.07 microg/L (larvae) for the 96-h aqueous test, and 2.90 microg/L (adult), 2.6 microg/L (larvae) for the 24-h sediment test. Larval grass shrimp were more sensitive to technical resmethrin and Scourge than the adult life stage. The results also demonstrate that synergized resmethrin is more toxic to P. pugio than the nonsynergized form, and that the presence of sediment decreases the toxicity of both resmethrin and Scourge.

Summary report of bioassays for the city of Hollywood water plant membrane reject water as it mixed with WWTP effluent in an ocean outfall environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fergen, R.E.; Vinci, P.; Bloetscher, F.

1999-07-01

A special bioassay study was conducted to review the impact of the City of Hollywood's Membrane Softening Water Treatment Plant (WRP) reject water as it mixes with the City's Wastewater Treatment Plant (WWTP) effluent. Three sampling periods occurred during 1997. The purpose of this study was to determine potential toxicity of the WTP reject water, pre-chlorinated effluent, and combined effluent, and to demonstrate if the combined effluent was acceptable for ocean discharge on the basis of no potential toxicity. Effluent was acceptable for ocean discharge on the basis of no potential toxicity. Effluent samples were collected at six sampling points;more » three were in the plant, while the other three were along the outfall pipeline. Definitive, static renewal bioassay tests were performed using Mysidopsis bahia and Menidia beryllina as indicators of potential toxicity. The bioassay tests at 30% effluent concentration indicate that there is not potential toxicity for the pre-chlorinated WTP effluent, WTP reject water, dechlorinate combined effluent at the plant, and chlorinated combined effluent at Holland Park, the riser, and the terminus. The results indicate that the WTP reject water (100%) is not toxic to Menidia beryllina but was toxic to Mysidopsis bahia. When combined with the WWRP effluent, the reject water's impact on the potential toxicity of the commingled effluent was insignificant. All of the tests indicate the combined effluents are not toxic to the species tested at the 30% effluent level. Therefore, potential toxicity concerns were not demonstrated for this outfall discharge and did not prevent FDEP from issuing a permit to the City of Hollywood for the disposal of the combined effluent. Furthermore, these results, in combination with the previous results, indicated that individual bioassay testing for the reject water for regulatory compliance is not required.« less

Toxicity of cadmium and lead on tropical midge larvae, Chironomus kiiensis Tokunaga and Chironomus javanus Kieffer (Diptera: Chironomidae)

PubMed Central

Ebau, Warrin; Rawi, Che Salmah Md; Din, Zubir; Al-Shami, Salman Abdo

2012-01-01

Objective To investigate the acute toxicity of cadmium and lead on larvae of two tropical Chironomid species, Chironomus kiiensis (C. kiiensis) Tokunaga and Chironomus javanus (C. javanus) Kieffer. Methods Different larval instars (first-fourth) were exposed using a static non-replacement testing procedures to various concentrations of cadmium and lead. Results In general, younger larvae (first and second instars) of both species were more sensitive to both metals than older larvae (third and forth instars). The toxic effects of the metals on C. kiiensis and C. javanus were influenced by the age of the larvae (first to fourth instars), types of metals (cadmium or lead) and duration of larval exposure (24, 48, 72 and 96 h) to the metals. Conclusions Cadmium was more toxic to the chironomids than lead and C. javanus was significantly more sensitive to both metals than C. kiiensis (P<0.05). PMID:23569984

A semistatic microplate-based phytotoxicity test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radetski, C.M.; Ferard, J.F.; Blaise, C.

1995-02-01

A novel phytotoxicity test is described herein that employs a microplate equipped with membrane-bottomed wells. This MultiScreen[trademark] (Millipore Corp., Bedford, MA) microplate allows performance of a semistatic algal test, in which test medium is renewed periodically. With such a design, the algal test becomes comparable to other short-term tests used to evaluate chronic toxicity of chemicals and effluents. The EC50s obtained for Cu[sup 2+], Cd[sup 2+], Cr[sup 6+], atrazine, and one leachate sample (municipal sludge incinerator residue) with static and semistatic algal microplate tests were compared in this study. The semistatic microplate test revealed greater sensitivity than did the staticmore » microplate test.« less

Acute toxicity of ammonia (NH3-N) in sewage effluent to Chironomus riparius: II. Using a generalized linear model

USGS Publications Warehouse

Monda, D.P.; Galat, D.L.; Finger, S.E.; Kaiser, M.S.

1995-01-01

Toxicity of un-ionized ammonia (NH3-N) to the midge, Chironomus riparius was compared, using laboratory culture (well) water and sewage effluent (≈0.4 mg/L NH3-N) in two 96-h, static-renewal toxicity experiments. A generalized linear model was used for data analysis. For the first and second experiments, respectively, LC50 values were 9.4 mg/L (Test 1A) and 6.6 mg/L (Test 2A) for ammonia in well water, and 7.8 mg/L (Test 1B) and 4.1 mg/L (Test 2B) for ammonia in sewage effluent. Slopes of dose-response curves for Tests 1A and 2A were equal, but mortality occurred at lower NH3-N concentrations in Test 2A (unequal intercepts). Response ofC. riparius to NH3 in effluent was not consistent; dose-response curves for tests 1B and 2B differed in slope and intercept. Nevertheless, C. riparius was more sensitive to ammonia in effluent than in well water in both experiments, indicating a synergistic effect of ammonia in sewage effluent. These results demonstrate the advantages of analyzing the organisms entire range of response, as opposed to generating LC50 values, which represent only one point on the dose-response curve.

Aquatic Toxicity Screening of Fire Fighting Agents; 2003 Report

DTIC Science & Technology

2003-06-02

Aqueous Film Forming Foam ( AFFF ), the reference toxicant. The aquatic toxicity screening consisted of an acute, static, range-finding...five concentrations of 3M Light Water Brand Aqueous Film Forming Foam ( AFFF ), the reference toxicant. The aquatic toxicity screening consisted of an...experimental foam concentrates against current Military Specification MIL-F-24385F Fire Extinguishing Agent, Aqueous Film Forming Foam

Acute toxicity of 4-nitrophenol, 2,4-dinitrophenol, terbufos and trichlorfon to grass shrimp (Palaemonetes spp.) and sheepshead minnows (Cyprinodon variegatus) as affected by salinity and temperature

USGS Publications Warehouse

Brecken-Folse, J. A.; Mayer, F.L.; Pedigo, L.E.; Marking, L.L.

1994-01-01

The toxicities of two industrial chemicals (4-nitrophenol and 2,4-dinitrophenol) and two organophosphate insecticides (terbufos and trichlorfon) to juvenile grass shrimp (Palaemonetes spp.) and sheepshead minnows (Cyprinodon vanegatus) were determined by static, 96-h toxicity tests in a factorial design with 12 combinations of salinity and temperature (15, 20, 25, 30ppt x 17, 22, 27°C). Concentrations of the toxicants, including bioconcentradon, were determined as appropriate by gas or liquid chromatography and the use of 14C-labeled compounds. The 96-h LC50s for 4-nitrophenol ranged from 12 to 31 mg/L and for 2,4-dinitrophenol from 13 to 50 mg/L. Toxicity decreased as salinity increased for 4-nitrophenol and both test organisms. Toxicity decreased as salinity increased for 2,4-dinitrophenol and sheepshead minnows, but toxicity to grass shrimp increased as salinity increased. Toxicity decreased with increased temperature for grass shrimp exposed to 2,4-dinitrophenol and sheepshead minnows exposed to 4-nitrophenol, increased with temperature for sheepshead minnows exposed to 2,4-dinitrophenol, and no change was observed for grass shrimp exposed to 4-nitrophenol. Bioconcentration of phenols in both test organisms increased as concentration increased. The 96-h LC50s for terbufos ranged from 3.4 to 6.6 μg/L and for trichlorfon from 6.3 to 19,300 μg/L. Terbufos and trichlorfon toxicity to grass shrimp and sheepshead minnows increased with increased temperature. BCFs for terbufos were greater in sheepshead minnows than grass shrimp, but were reversed for trichlorfon.

Acute toxicity of selected herbicides and surfactants to larvae of the midge Chironomus riparius

USGS Publications Warehouse

Buhl, Kevin J.; Faerber, Neil L.

1989-01-01

The acute toxicities of eight commercial herbicides and two surfactants to early fourth instar larvae of the midgeChironomus riparius were determined under static conditions. The formulated herbicides tested were Eradicane® (EPTC), Fargo® (triallate), Lasso® (alachlor), ME4 Brominal® (bromoxynil), Ramrod® (propachlor), Rodeo® (glyphosate), Sencor®(metribuzin), and Sutan (+)® (butylate); the two surfactants were Activator N.F.® and Ortho X-77®. In addition, technical grade alachlor, metribuzin, propachlor, and triallate were tested for comparison with the formulated herbicides. The relative toxicity of the commercial formulations, based on percent active ingredient, varied considerably. The EC50 values ranged from 1.23 mg/L for Fargo® to 5,600 mg/L for Rodeo®. Fargo®, ME4 Brominal®, and Ramrod®were moderately toxic to midge larvae; Lasso®, Sutan (+)®, and Eradicane® were slightly toxic; and Sencor® and Rodeo® were practically non-toxic. The 48-hr EC50 values of the two surfactants were nearly identical and were considered moderately toxic to midges. For two of the herbicides in which the technical grade material was tested, the inert ingredients in the formulations had a significant effect on the toxicity of the active ingredients. Fargo® was twice as toxic as technical grade triallate, whereas Sencor® was considerably less toxic than technical grade metribuzin. A comparison of the slope function values indicated that the toxic action of all the compounds occurred within a relatively narrow range. Published acute toxicity data on these compounds for other freshwater biota were tabulated and compared with our results. In general, the relative order of toxicity toC. riparius was similar to those for other freshwater invertebrates and fish. Maximum concentrations of each herbicide in bulk runoff during a projected “critical” runoff event were calculated as a percentage of the application rate lost in a given volume of runoff. A comparison between estimated maximum herbicide concentrations in runoff and results of acute tests indicated that Ramrod®, ME4 Brominal®, and Lasso® pose the greatest direct risk to midge larvae during a storm event.

Ecotoxicity hazard assessment of styrene.

PubMed

Cushman, J R; Rausina, G A; Cruzan, G; Gilbert, J; Williams, E; Harrass, M C; Sousa, J V; Putt, A E; Garvey, N A; St Laurent, J P; Hoberg, J R; Machado, M W

1997-07-01

The ecotoxicity of styrene was evaluated in acute toxicity studies of fathead minnows (Pimephales promelas), daphnids (Daphnia magna), amphipods (Hyalella azteca), and freshwater green algae (Selenastrum capricornutum), and a subacute toxicity study of earthworms (Eisenia fostida). Stable exposure levels were maintained in the studies with fathead minnows, daphnids, and amphipods using sealed, flowthrough, serial dilution systems and test vessels. The algae were evaluated in a sealed, static system. The earthworms were exposed in artificial soil which was renewed after 7 days. Styrene concentrations in water and soil were analyzed by gas chromatography with flame ionization detection following extraction into hexane. Test results are based on measured concentrations. Styrene was moderately toxic to fathead minnows, daphnids, and amphipods: fathead minnow: LC50 (96 hr), 10 mg/liter, and NOEC, 4.0 mg/liter; daphnids: EC50 (48 hr), 4.7 mg/liter, and NOEC, 1.9 mg/liter; amphipods: LC50 (96 hr), 9.5 mg/liter, and NOEC, 4.1 mg/liter. Styrene was highly toxic to green algae: EC50 (96 hr), 0.72 mg/liter, and NOEC, 0.063 mg/liter; these effects were found to be algistatic rather than algicidal. Styrene was slightly toxic to earthworms: LC50 (14 days), 120 mg/kg, and NOEC, 44 mg/kg. There was no indication of a concern for chronic toxicity based on these studies. Styrene's potential impact on aquatic and soil environments is significantly mitigated by its volatility and biodegradability.

Cytotoxicity assessment of modified bioactive glasses with MLO-A5 osteogenic cells in vitro.

PubMed

Modglin, Vernon C; Brown, Roger F; Jung, Steven B; Day, Delbert E

2013-05-01

The primary objective of this study was to evaluate in vitro responses of MLO-A5 osteogenic cells to two modifications of the bioactive glass 13-93. The modified glasses, which were designed for use as cell support scaffolds and contained added boron to form the glasses 13-93 B1 and 13-93 B3, were made to accelerate formation of a bioactive hydroxyapatite surface layer and possibly enhance tissue growth. Quantitative MTT cytotoxicity tests revealed no inhibition of growth of MLO-A5 cells incubated with 13-93 glass extracts up to 10 mg/ml, moderate inhibition of growth with 13-93 B1 glass extracts, and noticeable inhibition of growth with 13-93 B3 glass extracts. A morphology-based biocompatibility test was also performed and yielded qualitative assessments of the relative biocompatibilities of glass extracts that agree with those obtained by the quantitative MTT test. However, as a proof of concept experiment, when MLO-A5 cells were seeded onto 13-93 B3 scaffolds in a dynamic in vitro environment, cell proliferation occurred as evidenced by qualitative and quantitative MTT labeling of scaffolds. Together these results demonstrate the in vitro toxicity of released borate ion in static experiments; however borate ion release can be mitigated in a dynamic environment similar to the human body where microvasculature is present. Here we argue that despite toxicity in static environments, boron-containing 13-93 compositions may warrant further study for use in tissue engineering applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baca, B.J.; Getter, C.D.

Turtle grass beds, a valuable natural resource, are diminishing throughout the tropics because of damage from dredging, boats, and other factors. The toxicity of chemical dispersants and crude oil to turtle grass was determined in the laboratory to assess the potential for damage from spills occurring in the field. Studies of water-soluble fractions (WSF) of crude oil in static bioassays showed that a chemical dispersant (Corexit 9527) increased the amount of total oil in water more than 50-fold. The toxicity of chemically dispersed oil was assessed by conventional (96-h 50% lethal concentration) methods in static systems, and the results weremore » compared with toxicity measurements where the system was flushed after 12 h. Prudhoe Bay crude WSF was more toxic than dispersed oil or dispersant alone, possibly because of the large component of benzene, toluene, and C-2 benzene. The percentage of green (chlorophyllous) leaves was useful as evidence of toxicity. The importance of anatomical features such as recessed meristem and abundant leaf sheaths in protecting the growing region from waterborne pollutants was evident.« less

Bioassays with terrestrial and aquatic species as monitoring tools of hydrocarbon degradation.

PubMed

Bori, Jaume; Vallès, Bettina; Ortega, Lina; Riva, Maria Carme

2016-09-01

In this study chemical analyses and ecotoxicity tests were applied for the assessment of a heavily hydrocarbon-contaminated soil prior and after the application of a remediation procedure that consisted in the stimulation of soil autochthonous populations of hydrocarbon degraders in static-ventilated biopiles. Terrestrial bioassays were applied in mixtures of test soils and artificial control soil and studied the survival and reproduction of Eisenia fetida and the avoidance response of E. fetida and Folsomia candida. Effects on aquatic organisms were studied by means of acute tests with Vibrio fischeri, Raphidocelis subcapitata, and Daphnia magna performed on aqueous elutriates from test soils. The bioremediation procedure led to a significant reduction in the concentration of hydrocarbons (from 34264 to 3074 mg kg(-1), i.e., 91 % decrease) and toxicity although bioassays were not able to report a percentage decrease of toxicity as high as the percentage reduction. Sublethal tests proved the most sensitive terrestrial bioassays and avoidance tests with earthworms and springtails showed potential as monitoring tools of hydrocarbon remediation due to their high sensitivity and short duration. The concentrations of hydrocarbons in water extracts from test soils were 130 and 100 μg L(-1) before and after remediation, respectively. Similarly to terrestrial tests, most aquatic bioassays detected a significant reduction in toxicity, which was almost negligible at the end of the treatment. D. magna survival was the most affected by soil elutriates although toxicity to the crustacean was associated to the salinity of the samples rather than to the concentration of hydrocarbons. Ecotoxicity tests with aqueous soil elutriates proved less relevant in the assessment of hydrocarbon-contaminated soils due to the low hydrosolubility of hydrocarbons and the influence of the physicochemical parameters of the aquatic medium.

Recommended Water Quality Criteria for Octahydro-1,3,5,7-Tentranitro-1, 3,5,7-Tetrazocin (HMX).

DTIC Science & Technology

1989-03-27

possible to derive water quality criteria for protection of aquatic life following USEPA guidelines. Based on the NOAEL of 50 mg/kg/day from the 13-week...special reference to those on human, mammalian, and aquatic health effects, and to generate water quality criteria for drinking water and for the...and discussed below. Aquatic Invertebrates Bentley et al. (1977) performed static acute toxicity tests on four species of freshwater invertebrates

Acute toxic effects of two lampricides on twenty-one freshwater invertebrates

USGS Publications Warehouse

Rye, Robert P.; King, Everett Louis

1976-01-01

We conducted laboratory static bioassays to determine acute toxicity of two lampricides -- a 70% 2-aminoethanol salt of 5,2'dichloro-4'-nitrosalicylanilide (Bayer 73) and a mixture containing 98% 3-trifluoromethyl-4-nitrophenol (TFM) and 2% Bayer 73 (TFM-2B) -- to 21 freshwater invertebrates. LC50 values were determined for 24-h exposure periods at 12.8 C. Organisms relatively sensitive to Bayer 73 were a turbellarian (Dugesia tigrina), aquatic earthworms (Tubifex tubifex and Lumbriculus inconstans), snails (Physa sp.) and (Pleurocera sp.), a clam (Eliptio dilatatus), blackflies (Simulium sp.), leeches (Erpobdellidae), and a daphnid (Daphnia pulex). The invertebrates most sensitive to TFM-2B were turbellarians, aquatic earthworms (Tubifex), snails (Physa), blackflies, leeches, and burrowing mayflies (Hexagenia sp.). Bayer 73 was generally much more toxic to the test organisms than TFM-2B. At lampricidal concentrations, TFM-2B was more highly selective than Bayer 73 against larval sea lampreys (Petromyzon marinus).

Leaching of nitrogen, phosphorus, TOC and COD from the biosolids of the municipal wastewater treatment plant of Thessaloniki.

PubMed

Batziaka, V; Fytianos, K; Voudrias, E

2008-05-01

Biosolids from the WWTP of Thessaloniki were examined for the leaching of phosphorus (as PO4(3-) -P), nitrogen (as NH4+ (-N) and NO3- (-N)), and organic matter (as TOC and COD), using two tests: (1) a pH static leaching test and (2) a characterization test, relating contaminant release to the liquid to solid (L/S) ratio. Moreover, a Microtox toxicity test was conducted, to examine the pH dependency of the toxicity of the sludge leachate on the Vibrio fischeri bacterium. Maximum phosphorus release was observed at pH < 3 and at pH > 10. Ammonium nitrogen exhibited maximum leachability at near neutral pH conditions, while nitrate nitrogen exhibited a mild increase in the leachate, as the leachant pH increased from 2 to 12. Both TOC and COD exhibited an increase in the leachate concentration, as the leachant pH was increased from 2 to 12. Ecotoxicological analysis showed that maximum toxicity occurred at very low and very high pH-conditions. As liquid-to-solid ratio increased, the leachate concentration (in mg/l) of all parameters studied decreased. The results of the study were used to conduct a release assessment estimate for the case of Thessaloniki.

Lethal toxicity of industrial chemicals to early life stages of Tilapia guineensis.

PubMed

Ezemonye, L I N; Ogeleka, D F; Okieimen, F E

2008-08-30

The toxic effects of industrial chemicals on three early life stages of an economically important fish, Tilapia guineensis were investigated using the Organisation for Economic Cooperation and Development (OECD) # 203 recommended semi-static renewal bioassay. The assessment was necessary for the uncontrollable disposal of Neatex (liquid detergent) and Norust CR 486 (corrosion inhibitor) into the Niger Delta environment of Nigeria. The estimated 96-h LC(50) for 7-, 14- and 28-day-old fish in Norust CR 486 exposure was considered "more toxic" than Neatex in all life stages and was dependent on species age, exposure duration and environment. In the fresh water test, for Neatex and Norust CR 486 exposures for day 7, 14 and 28, the 96-h LC50 were 8.79, 17.10 and 82.42 mg/l and 5.55, 13.58 and 20.21 mg/l, respectively. In the brackish test, 15.42 and 46.52 mg/l, not determined (ND) and 7.35, 13.95 and 24.50mg/l were obtained. Differential toxicity was observed in the fresh and brackish water fish for the two chemicals and controls at p<0.05. The high sensitivity of the 7-day-old test organisms to both chemicals provides a rationale for regulatory surveillance and monitoring of both chemicals in the fragile Niger Delta environment.

Effects of TNT leakage from dumped ammunition on fish and invertebrates in static brackish water systems.

PubMed

Ek, Helene; Nilsson, Eva; Dave, Göran

2008-01-01

The objective of the present study was to study the release and effect of TNT from dumped ammunition. Cleaved artillery shells were placed in static brackish water systems for 5 months, and another 12 months with 5 cm sediment burial. The toxicity was determined in bioassays with crustaceans (Nitocra spinipes and Hyalella azteca) and/or European flounder (Platichtys flesus). The water phase was analysed for TNT using colorimetric method and GC-MS. This study showed a rapid release of TNT to acutely toxic concentrations when the cleaved ammuniton was not covered with sediment under static conditions, but that the release was effectively inhibited by sediment burial of the artillery shells. Hence, at least in a short-term perspective, acute adverse effects of sediment-buried ammunition on aquatic organisms should be greatly reduced.

Microcystin-LR toxicity on dominant copepods Eurytemora affinis and Pseudodiaptomus forbesi of the upper San Francisco Estuary.

PubMed

Ger, Kemal A; Teh, Swee J; Goldman, Charles R

2009-08-15

This study investigates the toxicity and post-exposure effects of dissolved microcystin (MC-LR) on the dominant copepods of the upper San Francisco Estuary (SFE), where blooms of the toxic cyanobacteria Microcystis aeruginosa coincide with record low levels in the abundance of pelagic organisms including phytoplankton, zooplankton, and fish. The potential negative impact of Microcystis on the copepods Eurytemora affinis and Pseudodiaptomus forbesi has raised concern for further depletion of high quality fish food. Response of copepods to MC-LR (MC) was determined using a 48-h standard static renewal method for acute toxicity testing. Following exposure, a life table test was performed to quantify any post-exposure impacts on survival and reproduction. The 48-h LC-50 and LC-10 values for MC were 1.55 and 0.14 mg/L for E. affinis; and 0.52 and 0.21 mg/L for P. forbesi. Copepod populations recovered once dissolved MC was removed and cultures returned to optimal conditions, suggesting no post-exposure effects of MC on copepod populations. Dissolved microcystin above 0.14 mg/L proved likely to have chronic effects on the survival of copepods in the SFE. Since such high concentrations are unlikely, toxicity from dissolved microcystin is not a direct threat to zooplankton of the SFE, and other mechanisms such as dietary exposure to Microcystis constitute a more severe risk.

Immobilization and phytotoxicity of chromium in contaminated soil remediated by CMC-stabilized nZVI.

PubMed

Wang, Yu; Fang, Zhanqiang; Kang, Yuan; Tsang, Eric Pokeung

2014-06-30

The toxic effect of Cr(VI)-contaminated soil remediated by sodium carboxymethyl cellulose stabilized nanoscale zero-valent iron (CMC-stabilized nZVI) was assessed through in vitro toxicity and phytotoxicity tests. In vitro tests showed that 0.09 g L(-1) of Fe(0) nanoparticles (soil-to-solution ratio was 1 g:5 mL) significantly reduced the toxicity characteristic leaching procedure (TCLP) leachability and physiological based extraction test (PBET) bioaccessibility of Cr by 82% and 58%, respectively. Sequential extraction procedures (SEP) revealed that exchangeable (EX) Cr was completely converted to Fe-Mn oxides (OX) and organic matter (OM). Accordingly, phytotoxicity tests indicated that after 72-h remediation, Cr uptakes by edible rape and Chinese cabbage were suppressed by 61% and 36%, respectively. Moreover, no significant increase in Cr uptake was observed for either species after a 1-month static period for the amended soil. Regarding Fe absorption, germination and seedling growth, both plant species were significantly affected by CMC-nZVI-exposed soils. However, similar phytotoxicity tests conducted after 1 month showed an improvement in cultivation for both plants. Overall, this study demonstrated that CMC-nZVI could significantly enhance Cr immobilization, which reduced its leachability, bioavailability and bioaccumulation by plants. From a detoxification perspective, such remediation is technologically feasible and shows great potential in field applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Development of a Perfusion Platform for Dynamic Cultivation of in vitro Skin Models.

PubMed

Strüver, Kay; Friess, Wolfgang; Hedtrich, Sarah

2017-01-01

Reconstructed skin models are suitable test systems for toxicity testing and for basic investigations on (patho-)physiological aspects of human skin. Reconstructed human skin, however, has clear limitations such as the lack of immune cells and a significantly weaker skin barrier function compared to native human skin. Potential reasons for the latter might be the lack of mechanical forces during skin model cultivation which is performed classically in static well-plate setups. Mechanical forces and shear stress have a major impact on tissue formation and, hence, tissue engineering. In the present work, a perfusion platform was developed allowing dynamic cultivation of in vitro skin models. The platform was designed to cultivate reconstructed skin at the air-liquid interface with a laminar and continuous medium flow below the dermis equivalent. Histological investigations confirmed the formation of a significantly thicker stratum corneum compared to the control cultivated under static conditions. Moreover, the skin differentiation markers involucrin and filaggrin as well as the tight junction proteins claudin 1 and occludin showed increased expression in the dynamically cultured skin models. Unexpectedly, despite improved differentiation, the skin barrier function of the dynamically cultivated skin models was not enhanced compared with the skin models cultivated under static conditions. © 2017 S. Karger AG, Basel.

Assessment of acute toxicity of carbofuran in Macrobrachium olfersii (Wiegmann, 1836) at different temperature levels.

PubMed

Barbieri, Edison; Moreira, Priscila; Luchini, Luiz Alberto; Hidalgo, Karla Ruiz; Muñoz, Alejandro

2016-01-01

Carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate; C12H15NO3) is one of the most toxic carbamate pesticides. For acute toxicity of carbofuran, juveniles of Macrobrachium olfersii were exposed to different concentrations of carbofuran using the static renewal method at different temperature levels (15, 20 and 25°C) at pH 7.0. The main purpose of the present study was to detect the acute toxicity of carbofuran to M. olfersii and investigate its effects on oxygen consumption and ammonium excretion; these tests have not been carried out in this species before. First, the acute toxicity - median lethal concentration - of carbofuran to M. olfersii for 24, 48, 72 and 96 h was examined, which resulted in the following values: 1.64, 1.22, 0.86 and 0.42 mg L(-1), respectively. Furthermore, we also found that carbofuran caused an inhibition in oxygen consumption of 60.6, 65.3 and 66.2% with respect to the control. In addition, after separate exposures to carbofuran, elevations in ammonium excretion were more than 500% with respect to the control. © The Author(s) 2013.

96 h LC50, behavioural alterations and histopathological effects due to wastewater toxicity in a freshwater fish Channa punctatus.

PubMed

Kaur, Rajbir; Dua, Anish

2015-04-01

The aim of the study was to evaluate the toxic impact of wastewater from sites 1 and 2 of Tung Dhab drain in the state of Punjab, India, on fish behaviour, morphology and gill histopathological biomarkers in comparison to control group. Static non-renewal tests were conducted for 96 h to determine LC50 of the wastewater for both sites using five concentrations (6.25-100%). Fish were regularly noticed for any deviation in behaviour and external morphology. Physico-chemical analysis of wastewater was done using standard methods recommended by APHA/AWWA/WEF (2005). Chronic toxicity tests were conducted for 15 and 30 days with sublethal concentrations of wastewater (50-90% of LC50) and gill histopathology was assessed. Wastewater near a paper mill was more toxic as observed from LC50 values of 72.45%. There was evident deterioration of water quality as the recorded values of some parameters were higher than the standard discharge limits. The test fish exhibited increased air gulping and surfacing, erratic movements initially and decreased opercular movements as the exposure period increased. Morphological observations include increased body colouration, mucus secretion, scale loss and haemorrhages on the skin and lower lip. Alterations in the gill histology such as complete lamellar fusion, epithelial lifting and intraepithelial oedema, haemorrhages, lamellar necrosis and aneurysm were noted in the test fish. Results demonstrate that the fish exposed to wastewater from both sites showed significantly greater change in gill organ index (IG) as compared to control fish for 15 and 30 days.

Comparative chronic toxicity of imidacloprid, clothianidin, and thiamethoxam to Chironomus dilutus and estimation of toxic equivalency factors.

PubMed

Cavallaro, Michael C; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

2017-02-01

Nontarget aquatic insects are susceptible to chronic neonicotinoid insecticide exposure during the early stages of development from repeated runoff events and prolonged persistence of these chemicals. Investigations on the chronic toxicity of neonicotinoids to aquatic invertebrates have been limited to a few species and under different laboratory conditions that often preclude direct comparisons of the relative toxicity of different compounds. In the present study, full life-cycle toxicity tests using Chironomus dilutus were performed to compare the toxicity of 3 commonly used neonicotinoids: imidacloprid, clothianidin, and thiamethoxam. Test conditions followed a static-renewal exposure protocol in which lethal and sublethal endpoints were assessed on days 14 and 40. Reduced emergence success, advanced emergence timing, and male-biased sex ratios were sensitive responses to low-level neonicotinoid exposure. The 14-d median lethal concentrations for imidacloprid, clothianidin, and thiamethoxam were 1.52 μg/L, 2.41 μg/L, and 23.60 μg/L, respectively. The 40-d median effect concentrations (emergence) for imidacloprid, clothianidin, and thiamethoxam were 0.39 μg/L, 0.28 μg/L, and 4.13 μg/L, respectively. Toxic equivalence relative to imidacloprid was estimated through a 3-point response average of equivalencies calculated at 20%, 50%, and 90% lethal and effect concentrations. Relative to imidacloprid (toxic equivalency factor [TEF] = 1.0), chronic (lethality) 14-d TEFs for clothianidin and thiamethoxam were 1.05 and 0.14, respectively, and chronic (emergence inhibition) 40-d TEFs were 1.62 and 0.11, respectively. These population-relevant endpoints and TEFs suggest that imidacloprid and clothianidin exert comparable chronic toxicity to C. dilutus, whereas thiamethoxam induced comparable effects only at concentrations an order of magnitude higher. However, the authors caution that under field conditions, thiamethoxam readily degrades to clothianidin, thereby likely enhancing toxicity. Environ Toxicol Chem 2017;36:372-382. © 2016 SETAC. © 2016 SETAC.

Role of exposure mode in the bioavailability of triphenyl phosphate to aquatic organisms

USGS Publications Warehouse

Huckins, James N.; Fairchild, James F.; Boyle, Terence P.

1991-01-01

A laboratory study was conducted to investigate the role of the route of triphenyl phosphate (TPP) entry on its aquatic bioavailability and acute biological effects. Three TPP treatments were used for exposures of fish and invertebrates. These consisted of TPP dosed directly into water with and without clean sediment and TPP spiked onto sediment prior to aqueous exposures. Results of static acute toxicity tests (no sediment) were 0.78 mg/L (96-h LC50) for bluegill, 0.36 mg/L (48-h EC50) for midge, and 0.25 mg/L (96-h EC50) for scud. At 24 h, the sediment (1.1% organic carbon)/water partition coefficient (Kp) for TPP was 112. Use of this partition coefficient model to predict the sediment-mediated reduction of TPP concentration in water during toxicity tests resulted in a value that was only 10% less than the nominal value. However, the required nominal concentration of TPP to cause acute toxicity responses in test organisms was significantly higher than the predicted value by the model for both clay and soil-derived sediment. Direct spiking of TPP to soil minimized TPP bioavailability. Data from parallel experiments designed to track TPP residues in water through time suggest that sorption kinetics control residue bioavailability in the initial 24 h of exposure and may account for observed differences in LC50 and EC50 values from the sediment treatments.

Photoenhanced toxicity of weathered oil to Mysidopsis bahia

USGS Publications Warehouse

Cleveland, L.; Little, E.E.; Calfee, R.D.; Barron, M.G.

2000-01-01

The toxicity of a water-accommodated fraction (WAF) prepared from weathered oil was assessed in a 7-day static renewal test with Mysidopsis bahia. Weathered oil was collected from the 5 x monitoring well at the Guadalupe oil field. Solar ultraviolet and visible light intensities were measured in various habitats in the vicinity of the weathered oil sample collection site, and the resultant measurements were used to produce laboratory light treatments that were representative of the on-site quality and intensity of natural solar radiation. Each of five WAF dilutions and a control without WAF was tested under three different simulated solar radiation intensities. During the test, survival and growth of the mysids, irradiance, and total petroleum hydrocarbon (TPH) concentrations in the test treatments were measured. Significant increases (P ??? 0.05) in mortality occurred among mysids exposed to 0.57 and 1.30 mg TPH/l and the effects were potentiated as irradiance increased. Seven-day LC50 (0.92-0.42 mg TPH/l) and LC20 (0.58-0.15 mg TPH/l) values decreased as the simulated solar irradiance increased. Calculated EC20 and EC50 values for mysid growth indicate that surviving mysids exposed to 0.1-1.0 mg TPH/l would incur significant reductions (P ??? 0.05) in productivity (biomass). Results of the present study indicate that effects elicited through the interaction of WAF of weathered oil and solar radiation will substantially increase the toxicity of weathered oil. Further, the photomediated effects of petroleum compounds measured as TPH on mysid survival and growth demonstrate a need to consider the interactions of ultraviolet light and contaminant to avoid under estimating toxicity that might occur in the environment. (C) 2000 Elsevier Science B.V.

Organotypic liver culture models: Meeting current challenges in toxicity testing

PubMed Central

LeCluyse, Edward L.; Witek, Rafal P.; Andersen, Melvin E.; Powers, Mark J.

2012-01-01

Prediction of chemical-induced hepatotoxicity in humans from in vitro data continues to be a significant challenge for the pharmaceutical and chemical industries. Generally, conventional in vitro hepatic model systems (i.e. 2-D static monocultures of primary or immortalized hepatocytes) are limited by their inability to maintain histotypic and phenotypic characteristics over time in culture, including stable expression of clearance and bioactivation pathways, as well as complex adaptive responses to chemical exposure. These systems are less than ideal for longer-term toxicity evaluations and elucidation of key cellular and molecular events involved in primary and secondary adaptation to chemical exposure, or for identification of important mediators of inflammation, proliferation and apoptosis. Progress in implementing a more effective strategy for in vitro-in vivo extrapolation and human risk assessment depends on significant advances in tissue culture technology and increasing their level of biological complexity. This article describes the current and ongoing need for more relevant, organotypic in vitro surrogate systems of human liver and recent efforts to recreate the multicellular architecture and hemodynamic properties of the liver using novel culture platforms. As these systems become more widely used for chemical and drug toxicity testing, there will be a corresponding need to establish standardized testing conditions, endpoint analyses and acceptance criteria. In the future, a balanced approach between sample throughput and biological relevance should provide better in vitro tools that are complementary with animal testing and assist in conducting more predictive human risk assessment. PMID:22582993

Variable tolerance to copper in two species from San Francisco Bay

USGS Publications Warehouse

Luoma, S.N.; Cain, D.J.; Ho, K.; Hutchinson, A.

1983-01-01

In static toxicity experiments, tolerance to soluble Cu of the bivalve, Macoma balthica, and the copepod, Acartia clausi, varied substantially among populations sampled within San Francisco Bay. Intraspecific tolerance differed ten-fold or more for both species over relatively small distances, suggesting geographical isolation of populations is not a prerequisite for the development of intraspecific differences in tolerance by aquatic organisms.In static toxicity experiments, tolerance to soluble Cu of the bivalve, Macoma balthica, and the copepod, Acartia clausi, varied substantially among populations sampled within San Francisco Bay. Intraspecific tolerance differed ten-fold or more for both species over relatively small distances, suggesting geographical isolation of populations is not a prerequisite for the development of intraspecific differences in tolerance by aquatic organisms. Refs.

Assessment of the photoenhanced toxicity of a weathered oil to the tidewater silverside

USGS Publications Warehouse

Little, Edward E.; Cleveland, Laverne; Calfee, Robin D.; Barron, Mace G.

2000-01-01

Studies were conducted to determine the interactive toxicity of a water-accommodated fraction (WAF) of a weathered middle distillate petroleum and solar radiation to an estuarine organism, the tidewater silverside (Menidia beryllina). Juvenile silversides were monitored for survival and growth during a 7-d static renewal exposure to dilutions of WAFs of an environmentally weathered oil collected in the vicinity of an abandoned oil field in California. Ultraviolet (UV) treatments were based on incident sunlight intensity and spectra measured at this site. Exposure to UV alone was not lethal to the fish, and WAF in the absence of UV was toxic at the highest total petroleum hydrocarbon (TPH) concentration (3.03 mg/L) after 96 h of exposure. Water-accommodated fractions toxicity increased significantly with increasing UV irradiance and duration of exposure. The 7-d LC50 concentrations for the control, low, medium, and high irradiance were 2.84, 1.27, 0.93, and 0.51 mg/L TPH, respectively. Significant mortality occurred among fish previously exposed to WAF in the absence of irradiance, whereas WAF toxicity was unaffected by UV exposure prior to the toxicity test. Thus, the mode of action is a photosensitization of the accumulated petroleum residue rather than a photoactivation of WAF. Chemical analysis indicates that the WAF contains limited amounts of polycyclic aromatic hydrocarbons (PAHs) known to be photoenhanced, suggesting that other constituents may be responsible for the observed photoenhanced toxicity.

Acute Toxicity of Smoke Screen Materials to Aquatic Organisms, White Phosphorus-Felt, Red Phosphorus-Butyl Rubber and SGF (Smoke Generator Fuel) No. 2 Fog Oil

DTIC Science & Technology

1986-04-01

anions (F’, Cl’, Br , N83%, S042-) in the water matrices. Detection limits were 0.02 mg/L for phosphate -P and 0.01 mg/L for phosphite -P...resulted in a lower ratio of phosphate to total P and also a lower ratio of phosphite to phosphate . Static and bubbling procedures and the resulting...testing, respectively. Changes with dilution in percentage of P as phosphate or phosphite were minor when ana- lyzed fresh and precipitation had not

Investigating apical adverse effects of four endocrine active substances in the freshwater gastropod Lymnaea stagnalis.

PubMed

Giusti, Arnaud; Lagadic, Laurent; Barsi, Alpar; Thomé, Jean-Pierre; Joaquim-Justo, Célia; Ducrot, Virginie

2014-09-15

The hermaphroditic gastropod Lymnaea stagnalis is proposed as a candidate species for the development of OECD guidelines for testing of the reprotoxicity of chemicals, including endocrine active substances (EASs). Up to now, only a few putative EASs have been tested for their reproductive toxicity in this species. In this study, we investigate the effects of four EASs with different affinities to the vertebrate estrogen and androgen receptors (chlordecone as an estrogen; cyproterone acetate, fenitrothion and vinclozolin as anti-androgens) on the reproduction of L. stagnalis in a 21-day semi-static test. Testosterone and 17α-ethinylestradiol (EE2) were used as the reference compounds. The tested EASs had no significant effect on growth and survival at the tested concentration ranges (ng to μg/L). Classical reproduction endpoints (i.e., oviposition and fecundity) were not responsive to the tested chemicals, except for chlordecone and 17α-ethinylestradiol, which hampered reproduction from 19.6 μg/L and 17.6 μg/L, respectively. The frequency of polyembryonic eggs, used as an additional endpoint, demonstrated the effects of all compounds except EE2. The molecular pathways, which are involved in such reproduction impairments, remain unknown. Our results suggest that egg quality is a more sensitive endpoint as compared to other reproductive endpoints commonly assessed in mollusk toxicity tests. Copyright © 2014 Elsevier B.V. All rights reserved.

Use of sodium dodecyl sulfate and zinc sulfate as reference substances for toxicity tests with the mussel Perna perna (Linnaeus, 1758) (Mollusca: Bivalvia).

PubMed

Jorge, R A D L V C; Moreira, G S

2005-06-01

Effects of anthropogenic pollution have been observed at different trophic levels in the oceans, and toxicity tests constitute one way of monitoring these alterations. The present assay proposes the use of two reference substances, sodium dodecyl sulfate (SDS) and zinc sulfate, for Perna perna larvae. This common mussel on the Brazilian coast is used as a bioindicator and is of economic interest. The chronic static embryo-larval test of short duration (48 h) was employed to determine the NOEC, LOEC, and IC50 for SDS and zinc sulfate, as well as the coefficient of variation. Salinity, pH and un-ionized ammonia (NH3) and dissolved oxygen (DO) concentrations were measured to monitor water quality. The results demonstrated that the main alterations in veliger larvae are the development of only one shell, protruded mantle, malformed shell, formation of only part of a valve, clipped edges, uneven sizes and presence of a concave or convex hinge. NOEC values were lower than 0.25 mg L(-1) for zinc sulfate and 0.68 mg L(-1) for SDS. The coefficient of variation was 17.63% and 2.50% for zinc sulfate and SDS, respectively.

Acute toxicity of endosulfan 35EC to two freshwater bivalve molluscs from Godavari river at Maharashtra State, India.

PubMed

Mane, U H; Muley, D V

1984-11-01

Static bioassay tests were conducted using commercial grade endosulfan 35EC to study its toxicity during different seasons to two species of Lamellidens from the Godavari river at Paithan (Maharashtra State). Acute toxicity studies for 96 h showed that both species of Lamellidens were more sensitive to endosulfan 35EC in summer, at times of high temperature, pH and total carbonate content of the water used, than in monsoon and winter. LC0 and LC50 values were determined for L. corrianus and L. marginalis, during summer, monsoon and winter. Statistical analyses showed that both species were more sensitive during summer (P less than 0.001) than in monsoon and winter and that L. marginalis was more sensitive to endosulfan 35EC than L. corrianus in summer (P less than 0.001). Behavioural changes and mortality of the bivalves were dose-related. Regression equations and 95% confidence limits for each species were established in different studies. The results are discussed in the light of possible effects of endosulfan on these species of bivalve molluscs.

Influence of increasing temperature and salinity on herbicide toxicity in estuarine phytoplankton.

PubMed

DeLorenzo, Marie E; Danese, Loren E; Baird, Thomas D

2013-07-01

Ecological risk assessments are, in part, based on results of toxicity tests conducted under standard exposure conditions. Global climate change will have a wide range of effects on estuarine habitats, including potentially increasing water temperature and salinity, which may alter the risk assessment of estuarine pollutants. We examined the effects of increasing temperature and salinity on the toxicity of common herbicides (irgarol, diuron, atrazine, and ametryn) to the phytoplankton species Dunaliella tertiolecta. Static 96-h algal bioassays were conducted for each herbicide under four exposure scenarios: standard temperature and salinity (25°C, 20 ppt), standard temperature and elevated salinity (25°C, 40 ppt), elevated temperature and standard salinity (35°C, 20 ppt), and elevated temperature and elevated salinity (35°C, 40 ppt). The endpoints assessed were algal cell density at 96 h, growth rate, chlorophyll a content, lipid content, and starch content. Increasing exposure temperature reduced growth rate and 96-h cell density but increased the cellular chlorophyll and lipid concentrations of the control algae. Exposure condition did not alter starch content of control algae. Herbicides were found to decrease growth rate, 96 h cell density, and cellular chlorophyll and lipid concentrations, while starch concentrations increased with herbicide exposure. Herbicide effects under standard test conditions were then compared with those observed under elevated temperature and salinity. Herbicide effects on growth rate, cell density, and starch content were more pronounced under elevated salinity and temperature conditions. To encompass the natural variability in estuarine temperature and salinity, and to account for future changes in climate, toxicity tests should be conducted under a wider range of environmental conditions. Copyright © 2011 Wiley Periodicals, Inc.

Using accelerated life testing procedures to compare the relative sensitivity of rainbow trout and the federally listed threatened bull trout to three commonly used rangeland herbicides (picloram, 2,4-D, and clopyralid).

PubMed

Fairchild, James F; Allert, Ann; Sappington, Linda S; Nelson, Karen J; Valle, Janet

2008-03-01

We conducted 96-h static acute toxicity studies to evaluate the relative sensitivity of juveniles of the threatened bull trout (Salvelinus confluentus) and the standard cold-water surrogate rainbow trout (Onchorhyncus mykiss) to three rangeland herbicides commonly used for controlling invasive weeds in the northwestern United States. Relative species sensitivity was compared using three procedures: standard acute toxicity testing, fractional estimates of lethal concentrations, and accelerated life testing chronic estimation procedures. The acutely lethal concentrations (ALC) resulting in 50% mortality at 96 h (96-h ALC50s) were determined using linear regression and indicated that the three herbicides were toxic in the order of picloram acid > 2,4-D acid > clopyralid acid. The 96-h ALC50 values for rainbow trout were as follows: picloram, 41 mg/L; 2.4-D, 707 mg/L; and clopyralid, 700 mg/L. The 96-h ALC50 values for bull trout were as follows: picloram, 24 mg/L; 2.4-D, 398 mg/L; and clopyralid, 802 mg/L. Fractional estimates of safe concentrations, based on 5% of the 96-h ALC50, were conservative (overestimated toxicity) of regression-derived 96-h ALC5 values by an order of magnitude. Accelerated life testing procedures were used to estimate chronic lethal concentrations (CLC) resulting in 1% mortality at 30 d (30-d CLC1) for the three herbicides: picloram (1 mg/L rainbow trout, 5 mg/L bull trout), 2,4-D (56 mg/L rainbow trout, 84 mg/L bull trout), and clopyralid (477 mg/L rainbow trout; 552 mg/L bull trout). Collectively, the results indicated that the standard surrogate rainbow trout is similar in sensitivity to bull trout. Accelerated life testing procedures provided cost-effective, statistically defensible methods for estimating safe chronic concentrations (30-d CLC1s) of herbicides from acute toxicity data because they use statistical models based on the entire mortality:concentration:time data matrix.

Using accelerated life testing procedures to compare the relative sensitivity of rainbow trout and the federally listed threatened bull trout to three commonly used rangeland herbicides (picloram, 2,4-D, and clopyralid)

USGS Publications Warehouse

Fairchild, J.F.; Allert, A.; Sappington, L.S.; Nelson, K.J.; Valle, J.

2008-01-01

We conducted 96-h static acute toxicity studies to evaluate the relative sensitivity of juveniles of the threatened bull trout (Salvelinus confluentus) and the standard cold-water surrogate rainbow trout (Onchorhyncus mykiss) to three rangeland herbicides commonly used for controlling invasive weeds in the northwestern United States. Relative species sensitivity was compared using three procedures: standard acute toxicity testing, fractional estimates of lethal concentrations, and accelerated life testing chronic estimation procedures. The acutely lethal concentrations (ALC) resulting in 50% mortality at 96 h (96-h ALC50s) were determined using linear regression and indicated that the three herbicides were toxic in the order of picloram acid > 2,4-D acid > clopyralid acid. The 96-h ALC50 values for rainbow trout were as follows: picloram, 41 mg/L; 2.4-D, 707 mg/L; and clopyralid, 700 mg/L. The 96-h ALC50 values for bull trout were as follows: picloram, 24 mg/L; 2.4-D, 398 mg/L; and clopyralid, 802 mg/L. Fractional estimates of safe concentrations, based on 5% of the 96-h ALC50, were conservative (overestimated toxicity) of regression-derived 96-h ALC5 values by an order of magnitude. Accelerated life testing procedures were used to estimate chronic lethal concentrations (CLC) resulting in 1% mortality at 30 d (30-d CLC1) for the three herbicides: picloram (1 mg/L rainbow trout, 5 mg/L bull trout), 2,4-D (56 mg/L rainbow trout, 84 mg/L bull trout), and clopyralid (477 mg/L rainbow trout; 552 mg/L bull trout). Collectively, the results indicated that the standard surrogate rainbow trout is similar in sensitivity to bull trout. Accelerated life testing procedures provided cost-effective, statistically defensible methods for estimating safe chronic concentrations (30-d CLC1s) of herbicides from acute toxicity data because they use statistical models based on the entire mortality:concentration: time data matrix. ?? 2008 SETAC.

Combined use of microbial consortia isolated from different agricultural soils and cyclodextrin as a bioremediation technique for herbicide contaminated soils.

PubMed

Villaverde, J; Rubio-Bellido, M; Lara-Moreno, A; Merchan, F; Morillo, E

2018-02-01

The phenylurea herbicide diuron is persistent in soil, water and groundwater and is considered to be a highly toxic molecule. The principal product of its biodegradation, 3,4-dichloroaniline, exhibits greater toxicity than diuron and is persistent in the environment. Five diuron degrading microbial consortia (C1C5), isolated from different agricultural soils, were investigated for diuron mineralization activity. The C2 consortium was able to mineralize 81.6% of the diuron in solution, while consortium C3 was only able to mineralize 22.9%. Isolated consortia were also tested in soil slurries and in all cases, except consortium C4, DT 50 (the time required for the diuron concentration to decline to half of its initial value) was drastically reduced, from 700 days (non-inoculated control) to 546, 351, and 171 days for the consortia C5, C2, and C1, respectively. In order to test the effectiveness of the isolated consortium C1 in a more realistic scenario, soil diuron mineralization assays were performed under static conditions (40% of the soil water-holding capacity). A significant enhancement of diuron mineralization was observed after C1 inoculation, with 23.2% of the herbicide being mineralized in comparison to 13.1% for the control experiment. Hydroxypropyl-β-cyclodextrin, a biodegradable organic enhancer of pollutant bioavailability, used in combination with C1 bioaugmentation in static conditions, resulted in a significant decrease in the DT 50 (214 days; 881 days, control experiment). To the best of our knowledge, this is the first report of the use of soil-isolated microbial consortia in combination with cyclodextrins proposed as a bioremediation technique for pesticide contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Single and joint toxicity assessment of four currently used pesticides to zebrafish (Danio rerio) using traditional and molecular endpoints.

PubMed

Wang, Yanhua; Wu, Shenggan; Chen, Jine; Zhang, Changpeng; Xu, Zhenlan; Li, Gang; Cai, Leiming; Shen, Weifeng; Wang, Qiang

2018-02-01

Pesticides usually present in mixtures in surface waters, although they are traditionally regulated on an individual basis in aquatic ecosystems. In this study, we aimed to investigate the lethal and transcriptional responses of individual and combined pesticides (iprodione, pyrimethanil, pyraclostrobin and acetamiprid) on zebrafish (Danio rerio). Semi-static toxicity test indicated that the greatest toxicity to the four life stages (embryonic, larval, juvenile and adult stages) of D. rerio was detected from pyraclostrobin, followed by iprodione and pyrimethanil. In contrast, the lowest toxicity to the organisms was found from acetamiprid. Most of the selected pesticides exerted greater toxicities to D. rerio of embryonic stage compared with other life stages. Synergistic responses were observed from all binary mixtures of iprodione in combination with pyrimethanil or acetamiprid and ternary mixtures of iprodione+pyraclostrobin in combination with pyrimethanil or acetamiprid. The expressions of 16 genes related to cell apoptosis pathway, oxidative stress response, innate immunity and endocrine disruption at the mRNA level showed that zebrafish embryos were affected by the individual or combined pesticides. The expressions of P53, Tnf, TRβ, Tsh and Cyp19a exhibited greater changes upon exposure to combined pesticides compared with individual pesticides. Taken together, increased toxicity might be triggered by the simultaneous presence of several pesticides in the aquatic environment, which seriously damaged the non-target organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of laboratory single species and field population-level effects of the pyrethroid insecticide lambda-cyhalothrin on freshwater invertebrates.

PubMed

Schroer, A F W; Belgers, J D M; Brock, T C M; Matser, A M; Maund, S J; Van den Brink, P J

2004-04-01

The toxicity of the pyrethroid insecticide lambda-cyhalothrin to freshwater invertebrates has been investigated using data from short-term laboratory toxicity tests and in situ bioassays and population-level effects in field microcosms. In laboratory tests, patterns of toxicity were consistent with previous data on pyrethroids. The midge Chaoborus obscuripes was most sensitive (48- and 96-h EC50 = 2.8 ng/L). Other insect larvae (Hemiptera, Ephemeroptera) and macrocrustacea (Amphipoda, Isopoda) were also relatively sensitive, with 48- and 96-h EC50 values between 10 and 100 ng/L. Generally, microcrustacea (Cladocera, Copepoda) and larvae of certain insect groups (Odonata and Chironomidae) were less sensitive, with 48-h EC50 values higher than 100 ng/L. Mollusca and Plathelminthes were insensitive and were unaffected at concentrations at and above the water solubility (5 microg/L). Generally, the EC50 values based on initial population responses in field enclosures were similar to values derived from laboratory tests with the same taxa. Also, the corresponding fifth and tenth percentile hazard concentrations (HC5 and HC10) were similar (laboratory HC5 = 2.7 ng/L and field HC5 = 4.1 ng/L; laboratory and field HC10 = 5.1 ng/L), at least when based on the same sensitive taxonomic groups (insects and crustaceans) and when a similar concentration range was taken into account. In the three field enclosure experiments and at a treatment level of 10 ng/L, consistent effects were observed for only one population (Chaoborus obscuripes), with recovery taking place within 3 to 6 weeks. The laboratory HC5 (2.7 ng/L) and HC10 (5.1 ng/L) based on acute EC50 values of all aquatic arthropod taxa were both lower than this 10 ng/L, a concentration that might represent the "regulatory acceptable concentration." The HC5 and HC10 values in this study in The Netherlands (based on static laboratory tests with freshwater arthropods) were very similar to those derived from a previous study in the United Kingdom (1.4 and 3.3 ng/L). This suggests that for pesticides like lambda-cyhalothrin, HC5 values based on static laboratory tests may provide a conservative estimate of the potential for community-level effects under field conditions. While these HC5 values are conservative for initial effects, they do not provide information on recovery potential, which may be important for regulatory decision-making.

Single and joint toxic effects of five selected pesticides on the early life stages of zebrafish (Denio rerio).

PubMed

Wang, Yanhua; Lv, Lu; Yu, Yijun; Yang, Guiling; Xu, Zhenlan; Wang, Qiang; Cai, Leiming

2017-03-01

Instead of individual ones, pesticides are usually detected in water environment as mixtures of contaminants. Laboratory tests were conducted in order to investigate the effects of individual and joint pesticides (phoxim, atrazine, chlorpyrifos, butachlor and λ-cyhalothrin) on zebrafish (Denio rerio). Results from 96-h semi-static toxicity test indicated that λ-cyhalothrin had the greatest toxicity to the three life stages (embryonic, larval and juvenile stages) of D. rerio with LC 50 values ranging from 0.0031 (0.0017-0.0042) to 0.38 (0.21-0.53) mg a.i. L -1 , followed by butachlor and chlorpyrifos with LC 50 values ranging from 0.45 (0.31-0.59) to 1.93 (1.37-3.55) and from 0.28 (0.13-0.38) to 13.03 (7.54-19.71) mg a.i. L -1 , respectively. In contrast, atrazine showed the least toxicity with LC 50 values ranging from 6.09 (3.34-8.35) to 34.19 (24.42-51.9) mg a.i. L -1 . The larval stage of D. rerio was a vulnerable period to most of the selected pesticides in the multiple life stages tested. Pesticide mixtures containing phoxim and λ-cyhalothrin exerted synergistic effects on the larvae of D. rerio. Moreover, the binary mixture of phoxim-atrazine also displayed synergistic response to zebrafish. It has been assumed that most chemicals are additive in toxicity. Therefore, it is crucial to clarify the synergistic interaction for pesticide regulators and environment managers. In the present study, our data provided a clear picture on ecological risk of these pesticide mixtures to aquatic organisms. Moreover, joint effects play a more important role than individual ones, which require more attention when defining standard for water environment quality and risk assessment protocols. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differences in susceptibility of five cladoceran species to two systemic insecticides, imidacloprid and fipronil.

PubMed

Hayasaka, Daisuke; Korenaga, Tomoko; Suzuki, Kazutaka; Sánchez-Bayo, Francisco; Goka, Koichi

2012-03-01

Differences in susceptibility of five cladocerans to the neonicotinoid imidacloprid and the phenyl-pyrazole fipronil, which have been dominantly used in rice fields of Japan in recent years, were examined based on short-term (48-h), semi-static acute immobilization exposure tests. Additionally, we compared the species sensitivity distribution (SSD) patterns of both insecticides between two sets of species: the five tested cladocerans and all other aquatic organisms tested so far, using data from the ECOTOX database of U.S. Environmental Protection Agency (USEPA). The sensitivity of the test species to either imidacloprid or fipronil was consistent, spanning similar orders of magnitude (100 times). At the genus level, sensitivities to both insecticides were in the following descending order: Ceriodaphnia > Moina > Daphnia. A positive relationship was found between body lengths of each species and the acute toxicity (EC(50)) of the insecticides, in particular fipronil. Differences in SSD patterns of imidacloprid were found between the species groups compared, indicating that test cladocerans are much less susceptible than other aquatic species including amphibians, crustaceans, fish, insects, mollusks and worms. However, the SSD patterns for fipronil indicate no difference in sensitivity between cladocerans tested and other aquatic organisms despite the greater exposure, which overestimates the results, of our semi-static tests. From these results, Ceriodaphnia sp. should be considered as more sensitive bioindicators (instead of the standard Daphnia magna) for ecotoxicological assessments of aquatic ecosystems. In addition, we propose that ecotoxicity data associated with differences in susceptibility among species should be investigated whenever pesticides have different physicochemical properties and mode of action.

The effects of salinity, pH, and dissolved organic matter on acute copper toxicity to the rotifer, Brachionus plicatilis ("L" strain).

PubMed

Arnold, W R; Diamond, R L; Smith, D S

2010-08-01

This paper presents data from original research for use in the development of a marine biotic ligand model and, ultimately, copper criteria for the protection of estuarine and marine organisms and their uses. Ten 48-h static acute (unfed) copper toxicity tests using the euryhaline rotifer Brachionus plicatilis ("L" strain) were performed to assess the effects of salinity, pH, and dissolved organic matter (measured as dissolved organic carbon; DOC) on median lethal dissolved copper concentrations (LC50). Reconstituted and natural saltwater samples were tested at seven salinities (6, 11, 13, 15, 20, 24, and 29 g/L), over a pH range of 6.8-8.6 and a range of dissolved organic carbon of <0.5-4.1 mg C/L. Water chemistry analyses (alkalinity, calcium, chloride, DOC, hardness, magnesium, potassium, sodium, salinity, and temperature) are presented for input parameters to the biotic ligand model. In stepwise multiple regression analysis of experimental results where salinity, pH, and DOC concentrations varied, copper toxicity was significantly related only to the dissolved organic matter content (pH and salinity not statistically retained; alpha=0.05). The relationship of the 48-h dissolved copper LC50 values and dissolved organic carbon concentrations was LC50 (microg Cu/L)=27.1xDOC (mg C/L)1.25; r2=0.94.

Experimental characterization of composites. [load test methods

NASA Technical Reports Server (NTRS)

Bert, C. W.

1975-01-01

The experimental characterization for composite materials is generally more complicated than for ordinary homogeneous, isotropic materials because composites behave in a much more complex fashion, due to macroscopic anisotropic effects and lamination effects. Problems concerning the static uniaxial tension test for composite materials are considered along with approaches for conducting static uniaxial compression tests and static uniaxial bending tests. Studies of static shear properties are discussed, taking into account in-plane shear, twisting shear, and thickness shear. Attention is given to static multiaxial loading, systematized experimental programs for the complete characterization of static properties, and dynamic properties.

In vitro degradation and in vivo toxicity of NanoMatrix3D® polycaprolactone and poly(lactic acid) nanofibrous scaffolds.

PubMed

Pogorielov, Maksym; Hapchenko, Andrii; Deineka, Volodymyr; Rogulska, Larysa; Oleshko, Olexandr; Vodseďálková, Kateřina; Berezkinová, Liliana; Vysloužilová, Lucie; Klápšťová, Andrea; Erben, Jakub

2018-04-10

Nanofibrous materials present unique properties favorable in many biomedicine and industrial applications. In this research we evaluated biodegradation, tissue response and general toxicity of nanofibrous poly(lactic acid) (PLA) and polycaprolactone (PCL) scaffolds produced by conventional method of electrospinning and using NanoMatrix3D ® (NM3D ® ) technology. Mass density, scanning electron microscopy and in vitro degradation (static and dynamic) were used for material characterization, and subcutaneous, intramuscular and intraperitoneal implantation - for in vivo tests. Biochemical blood analysis and histology were used to assess toxicity and tissue response. Pore size and fiber diameter did not differ in conventional and NM3D ® PLA and PCL materials, but mass density was significantly lower in NM3D ® ones. Scaffolds made by conventional method showed toxic effect during the in-vivo tests due to residual concentration of chloroform that released with material degradation. NM3D ® method allowed cleaning scaffolds from residual solutions that made them nontoxic and biocompatible. Subcutaneous, intramuscular and intraperitoneal implantation of PCL and PLA NM3D ® electrospun nanofibrous scaffolds showed their appropriate cell conductive properties, tissue and vessels formation in all sites. Thus, NM3D ® PCL and PLA nanofibrous electrospun scaffolds can be used in the field of tissue engineering, surgery, wound healing, drug delivery, and so forth, due to their unique properties, nontoxicity and biocompatibility. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 00A:000-000, 2018. © 2018 Wiley Periodicals, Inc.

76 FR 28131 - Federal Motor Vehicle Safety Standards; Motorcycle Helmets

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-13

..., this final rule sets a quasi-static load application rate for the helmet retention system; revises the... Analysis and Conclusion e. Quasi-Static Retention Test f. Helmet Conditioning Tolerances g. Other... it as a quasi-static test, instead of a static test. Specifying the application rate will aid...

Evaluation of chemical control for nonnative crayfish at a warm-water fish production hatchery

USGS Publications Warehouse

Allert, Ann L.; McKee, M.J.; DiStefano, R.J.; Fairchild, J.F.

2016-01-01

Invasive crayfish are known to displace native crayfish species, alter aquatic habitat and community structure and function, and are serious pests for fish hatcheries. White River Crawfish (WRC; Procambarus acutus) were inadvertently introduced to a warm-water fish hatchery in Missouri, USA, possibly in an incoming fish shipment. We evaluated the use of chemical control for crayfish to ensure incoming and outgoing fish shipments from hatcheries do not contain live crayfish. We conducted acute (≤24 hr) static toxicity tests to determine potency, dose-response, and selectivity of pesticides to WRC, Virile Crayfish (VC; Orconectes virilis), and Fathead Minnow (FHM; Pimephales promelas). Testing identified a formulation of cypermethrin (Cynoff®) as the most potent of five pesticides evaluated for toxicity to crayfish. A 4-hr exposure to a cypermethrin concentration of 100 μg · L-1 was found to kill 100% of juvenile and adult WRC; however, adult VC were not consistently killed. Concentrations of cypermethrin ≤100 μg · L-1 did not cause significant (>10%) mortality in juvenile FHM. Additional testing is needed to examine selectivity between crayfish and hatchery fish species. Biosecurity protocols at hatcheries that use chemical control have the potential to reliably prevent inadvertent transfers of live crayfish in fish shipments.

Results of the recent precipitation static flight test program on the Navy P-3B antisubmarine aircraft

NASA Technical Reports Server (NTRS)

Whitaker, Mike

1991-01-01

Severe precipitation static problems affecting the communication equipment onboard the P-3B aircraft were recently studied. The study was conducted after precipitation static created potential safety-of-flight problems on Naval Reserve aircraft. A specially designed flight test program was conducted in order to measure, record, analyze, and characterize potential precipitation static problem areas. The test program successfully characterized the precipitation static interference problems while the P-3B was flown in moderate to extreme precipitation conditions. Data up to 400 MHz were collected on the effects of engine charging, precipitation static, and extreme cross fields. These data were collected using a computer controlled acquisition system consisting of a signal generator, RF spectrum and audio analyzers, data recorders, and instrumented static dischargers. The test program is outlined and the computer controlled data acquisition system is described in detail which was used during flight and ground testing. The correlation of test results is also discussed which were recorded during the flight test program and those measured during ground testing.

Toxicity of oil dispersant, crude oil and dispersed crude oil to a marine amphipod and gastropod

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulec, I.; Holdway, D.A.

1995-12-31

The importance of appropriate oil spill remedial action was emphasized during the recent Iron Barron oil spill off of the Tamar river in North Tasmania. One important potential oil spill response is dispersion, but little information exists on the toxicity of dispersants and dispersed oil to Australian marine species. This research was undertaken to assess the acute toxicity of Corexit 9527 (a widely used dispersant), water accommodated fractions of Bass Strait crude oil and dispersed Bass Strait crude oil, to the saltwater amphipod, Allorchestes compressa under semi-static conditions. Acute 96 h LC50`s were determined for each toxicant as well asmore » for the reference toxicants sodium dodecyl sulfate (SDS) and zinc sulfate. Sublethal bioassays were undertaken for the same 3 toxicants utilizing the marines and snail Polinices conicus as the test species. No-observed-effect-concentrations (NOEC) and lowest-observed-effect-concentrations (LOEC) were determined using ANOVA while EC50`s and EC0`s were calculated using regression analysis. Mean acute 96 h LC50 (S.E.) values for A. compressa exposed to SDS and zinc sulfate were 3.6 mg/l (0.28) and 41.6 mg/l (9.01) respectively. EC50 (S.E.) concentrations for P. conicus exposed to SDS and zinc sulfate for 30 minutes were 44.7 mg/l and 246 mg/l respectively using burying behavior as an endpoint. These sublethal EC50`s were reduced to 20.7 mg/l for SDS and 23.5 mg/l for zinc sulfate following 24 hours of exposure.« less

Individual and mixture effects of five agricultural pesticides on zebrafish (Danio rerio) larvae.

PubMed

Wang, Yanhua; Yang, Guiling; Dai, Dejiang; Xu, Zhenlan; Cai, Leiming; Wang, Qiang; Yu, Yijun

2017-02-01

In the present study, we evaluated the individual and mixture toxicities of imidacloprid and other four pesticides (atrazine, chlorpyrifos, butachlor, and λ-cyhalothrin) to the zebrafish (Danio rerio) larvae in order to clarify the interactive effects of pesticides on aquatic organisms. Results from the 96-h semi-static toxicity test indicated that chlorpyrifos, λ-cyhalothrin, and butachlor had the highest toxicities to D. rerio with an LC 50 value ranging from 0.28 (0.13∼0.38) to 0.45 (0.31∼0.59) mg AI L -1 , followed by atrazine with an LC 50 value of 15.63 (10.71∼25.76) mg AI L -1 , while imidacloprid exhibited the least toxicity to the organisms with an LC 50 value of 143.7 (99.98∼221.6) mg AI L -1 . Seven pesticide mixtures (two binary mixtures of imidacloprid + atrazine and imidacloprid + λ-cyhalothrin, two ternary mixtures of imidacloprid + atrazine + λ-cyhalothrin and imidacloprid + butachlor + λ-cyhalothrin, two quaternary mixtures of imidacloprid + atrazine + chlorpyrifos + λ-cyhalothrin and imidacloprid + chlorpyrifos + butachlor + λ-cyhalothrin, and one quinquenary mixture of imidacloprid + atrazine + chlorpyrifos + butachlor + λ-cyhalothrin) exhibited synergistic effects with equitoxic ratio and equivalent concentration on the zebrafish. Our results highlighted that the simultaneous presence of several pesticides in the aquatic environment might lead to increased toxicity, causing serious damage to the aquatic ecosystems compared with their individual toxicities. Therefore, the toxic effects of both individual pesticides and their mixtures should be incorporated into the environmental risk evaluation of pesticides.

ACUTE TOXICITY OF SELECTED ORGANIC COMPOUNDS TO FATHEAD MINNOWS

EPA Science Inventory

Static nonrenewal laboratory bioassays were conducted with 26 organic compounds commonly used by industry. The selected compounds represented the five following chemical classes: acids, alcohols, hydrocarbons, ketones and aldehydes, and phenols. Juvenile fathead minnows (Pimephal...

A Comparison of Quasi-Static Indentation Testing to Low Velocity Impact Testing

NASA Technical Reports Server (NTRS)

Nettles, Alan T.; Douglas, Michael J.

2001-01-01

The need for a static test method for modeling low-velocity foreign object impact events to composites would prove to be very beneficial to researchers since much more data can be obtained from a static test than from an impact test. In order to examine if this is feasible, a series of static indentation and low velocity impact tests were carried out and compared. Square specimens of many sizes and thickness were utilized to cover the array of types of low velocity impact events. Laminates with a n/4 stacking sequence were employed since this is by the most common type of engineering laminate. Three distinct flexural rigidities under two different boundary conditions were tested in order to obtain damage due to large deflections, contact stresses and both to examine if the static indentation-impact comparisons are valid under the spectrum of damage modes that can be experienced. Comparisons between static indentation and low velocity impact tests were based on the maximum applied transverse load. The dependent parameters examined included dent depth, back surface crack length, delamination area and to a limited extent, load-deflection behavior. Results showed that no distinct differences could be seen between the static indentation tests and the low velocity impact tests, indicating that static indentation can be used to represent a low velocity impact event.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becker, C.D.; Woodfield, W.G.; Strand, J.A.

The Freshwater Sciences Section of PNL has initiated biologically oriented studies at the P and M solvent refined coal (SRC) pilot plant on the Fort Lewis Reservation in western Washington. Essentially, the study objectives are to identify residual components in the treated SRC process and assess potential for adverse impact on water quality and aquatic biota. Since inception of research in mid-1976, six static toxicity tests with treated SRC process effluent have been conducted. Toxic components, not yet specifically identified, sometimes occur in the effluent. It is believed these components involve organic hydrocarbons of the phenol and cresol groups. Analysesmore » have been obtained on inorganic and organic constituents in partially-treated and treated process effluent. Concentrations of inorganics identified in the effluent did not differ greatly from their concentrations in Lake Sequalitchew or SRC plant tap water, but the low concentrations may be due primarily to dilution with freshwater before discharge. Organics identified in the effluent are similar to those found in samples contaminated with petroleum, and involve many complex hydrocarbons.« less

40 CFR 53.64 - Test procedure: Static fractionator test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Test procedure: Static fractionator test. 53.64 Section 53.64 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Performance Characteristics of Class II Equivalent Methods for PM2.5 § 53.64 Test procedure: Static...

40 CFR 53.64 - Test procedure: Static fractionator test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Test procedure: Static fractionator test. 53.64 Section 53.64 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Performance Characteristics of Class II Equivalent Methods for PM2.5 § 53.64 Test procedure: Static...

Vertical Force-deflection Characteristics of a Pair of 56-inch-diameter Aircraft Tires from Static and Drop Tests with and Without Prerotation

NASA Technical Reports Server (NTRS)

Smiley, Robert F; Horne, Walter B

1957-01-01

The vertical force-deflection characteristics were experimentally determined for a pair of 56-inch-diameter tires under static and drop-test conditions with and without prerotation. For increasing force, the tires were found to be least stiff for static tests, almost the same as for the static case for prerotation drop tests as long as the tires remain rotating, and appreciably stiffer for drop tests without prerotation.

Acute and sub-chronic toxicity of four cytostatic drugs in zebrafish.

PubMed

Kovács, Róbert; Bakos, Katalin; Urbányi, Béla; Kövesi, Judit; Gazsi, Gyöngyi; Csepeli, Andrea; Appl, Ádám János; Bencsik, Dóra; Csenki, Zsolt; Horváth, Ákos

2016-08-01

The acute and sub-chronic effects of four cytostatic drugs-5-fluorouracil (5-FU), cisplatin (CisPt), etoposide (ET) and imatinib mesylate (IM)-on zebrafish (Danio rerio) were investigated. Acute tests were carried out in a static system in accordance with the OECD guideline 203 for adult fish and the draft guideline for fish embryos (FET test) in order to find the LC50 values of the four cytostatic drugs. Early-life stage toxicity test on zebrafish was conducted according the OECD guideline 210 using the cytostatic drugs 5-FU and IM in a semistatic system with the objective of investigating the sub-chronic effects of the cytostatic drugs on fish. In adult fish, the cytostatic drugs 5-FU and ET did not pass the limit test, thus, are considered non-toxic. In case of cisplatin, LC50 was calculated at 64.5 mg L(-1), whereas in case of IM, LC50 was at 70.8 mg L(-1). In the FET test, LC50 of 5-FU at 72-h post fertilization (hpf) was 2441.6 mg L(-1). In case of CisPt, LC50 was 349.9 mg L(-1) at 48 hpf and it progressively decreased to 81.3 mg L(-1) at 120 hpf. In addition, CisPt caused a significant delay in the hatch of larvae. In case of ET, LC50 values were not calculable as they were higher than 300 mg L(-1) at which concentration the substance crystallized in the solution. LC50 values of IM were 48 hpf; 158.3 mg L(-1) , 72 hpf; 141.6 mg L(-1), 96 hpf; 118.0 mg L(-1), and 120 hpf; 65.9 mg L(-1). In the Early-life Stage Test with 5-FU, embryonic deformities were not detected during the tests. Regarding mortalities, the 10 mg L(-1) concentration can be considered as LOEC, as statistically significant difference in mortalities was detected in this group alone. Concerning dry body weight and standard length, 1 mg L(-1) is the LOEC. In case of IM, the highest tested concentration (10 mg L(-1)) can be considered LOEC for mortalities, however, the treatment did not have an effect on the other investigated parameters (dry and wet weight, standard length). All four cytostatic drugs were characterized by low toxicity in zebrafish in acute and sub-chronic tests.

Assessment of Marine Coatings at a Central California Static Immersion Test Site

DTIC Science & Technology

2016-10-27

VA 220600-6218 RE: Contract Number N00014-15-1-2321 Assessment of Marine Coatings at a Central California Static Immersion Test Site Principal...Technical Report 05/01/2015 - 07/29/2016 Assessment of Marine Coatings at a Central California Static Immersion Test Site Dean E. Wendt Cal Poly...to test the relationships between the recruitment of fouling organisms to intersite panels and water quality parameters. The static immersion site

Effect of inlet disturbances on fan inlet noise during a static test

NASA Technical Reports Server (NTRS)

Bekofske, K. L.; Sheer, R. E., Jr.; Wang, J. C. F.

1977-01-01

Measurements of fan rotor inlet noise taken during static test situations are at variance with aircraft engine flight data. In particular, static tests generally yield a significantly higher tone at blade passage frequency than that measured during flight. To explain this discrepancy, the extent of the influence of inlet ground vortices and large-scale inlet turbulence on the forward-radiated fan noise measured at a static test facility was investigated. While such inlet disturbances were generated intentionally in an anechoic test chamber, far-field acoustic measurements and inlet flow-field hot-film mappings of a fan rotor were obtained. Experimental results indicate that the acoustic effect of such disturbances appears to be less severe for supersonic than for subsonic tip speeds. Further, a reverse flow that occurs on the exterior cowl in static test facilities appears to be an additional prime candidate for creating inlet disturbances and causing variance between flight and static acoustic data.

Acute toxicity of 6 neonicotinoid insecticides to freshwater invertebrates.

PubMed

Raby, Melanie; Nowierski, Monica; Perlov, Dmitri; Zhao, Xiaoming; Hao, Chunyan; Poirier, David G; Sibley, Paul K

2018-05-01

Neonicotinoids are a group of insecticides commonly used in agriculture. Due to their high water solubility, neonicotinoids can be transported to surface waters and have the potential to be toxic to aquatic life. The present study assessed and compared the acute (48- or 96-h) toxicity of 6 neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam) to 21 laboratory-cultured and field-collected aquatic invertebrates spanning 10 aquatic arthropod orders. Test conditions mimicked species' habitat, with lentic taxa exposed under static conditions, and lotic taxa exposed under recirculating systems. Median lethal concentrations (LC50s) and median effect concentrations (EC50s; immobility) were calculated and used to construct separate lethal- and immobilization-derived species sensitivity distributions for each neonicotinoid, from which 5th percentile hazard concentrations (HC5s) were calculated. The results showed that the most sensitive invertebrates were insects from the orders Ephemeroptera (Neocloeon triangulifer) and Diptera (Chironomus dilutus), whereas cladocerans (Daphnia magna, Ceriodaphnia dubia) were the least sensitive. The HC5s were compared with neonicotinoid environmental concentrations from Ontario (Canada) monitoring studies. For all neonicotinoids except imidacloprid, the resulting hazard quotients indicated little to no hazard in terms of acute toxicity to aquatic communities in Ontario freshwater streams. For the neonicotinoid imidacloprid, a moderate hazard was found when only invertebrate immobilization, and not lethality, data were considered. Environ Toxicol Chem 2018;37:1430-1445. © 2018 SETAC. © 2018 SETAC.

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

33 CFR 183.580 - Static pressure test for fuel tanks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Static pressure test for fuel... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested by performing the following procedures in the following...

GENERAL VIEW LOOKING NORTHWEST AT THE SATURN V STATIC TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GENERAL VIEW LOOKING NORTHWEST AT THE SATURN V STATIC TEST FACILITY. THIS TEST FACILITY WAS DESIGNED TO RESIST THE 12 MILLION POUNDES OF THRUST GENERATED BY THE THE SATURN V FIRST STAGE ENGINE CLUSTER. - Marshall Space Flight Center, Saturn V S-IC Static Test Facility, West Test Area, Huntsville, Madison County, AL

Determination of the acute toxicity of isoniazid to three invasive carp species and rainbow trout in static exposures

USGS Publications Warehouse

Schreier, Theresa M.; Hubert, Terrance D.

2015-01-01

Three invasive fishes of considerable concern to aquatic resource managers are the Hypophthalmichthys nobilis (bighead carp),Hypophthalmichthys molitrix (silver carp), and Ctenopharyngodon idella (grass carp), collectively known as Asian carps. There is a need for an effective chemical control agent for Asian carps. Isoniazid was identified as a potential toxicant for grass carp. The selective toxicity of isoniazid to grass carp was verified as a response to an anecdotal report received in 2013. In addition, the toxicity of isoniazid to bighead carp, silver carp, and Oncorhynchus mykiss (rainbow trout) was evaluated. Isoniazid was not toxic to grass carp at the reported anecdotal concentration, which was 13 milligrams per liter. Isoniazid (130 milligrams per liter) was not selectively toxic to bighead carp, silver carp, or grass carp when compared to rainbow trout.

Comparative Tests of Pitot-static Tubes

NASA Technical Reports Server (NTRS)

Merriam, Kenneth G; Spaulding, Ellis R

1935-01-01

Comparative tests were made on seven conventional Pitot-static tubes to determine their static, dynamic, and resultant errors. The effect of varying the dynamic opening, static opening, wall thickness, and inner-tube diameter was investigated. Pressure-distribution measurements showing stem and tip effects were also made. A tentative design for a standard Pitot-static tube for use in measuring air velocity is submitted.

Finite element modeling of ROPS in static testing and rear overturns.

PubMed

Harris, J R; Mucino, V H; Etherton, J R; Snyder, K A; Means, K H

2000-08-01

Even with the technological advances of the last several decades, agricultural production remains one of the most hazardous occupations in the United States. Death due to tractor rollover is a prime contributor to this hazard. Standards for rollover protective structures (ROPS) performance and certification have been developed by groups such as the Society of Automotive Engineers (SAE) and the American Society of Agricultural Engineers (ASAE) to combat these problems. The current ROPS certification standard, SAE J2194, requires either a dynamic or static testing sequence or both. Although some ROPS manufacturers perform both the dynamic and static phases of SAE J2194 testing, it is possible for a ROPS to be certified for field operation using static testing alone. This research compared ROPS deformation response from a simulated SAE J2194 static loading sequence to ROPS deformation response as a result of a simulated rearward tractor rollover. Finite element analysis techniques for plastic deformation were used to simulate both the static and dynamic rear rollover scenarios. Stress results from the rear rollover model were compared to results from simulated static testing per SAE J2194. Maximum stress values from simulated rear rollovers exceeded maximum stress values recorded during simulated static testing for half of the elements comprising the uprights. In the worst case, the static model underpredicts dynamic model results by approximately 7%. In the best case, the static model overpredicts dynamic model results by approximately 32%. These results suggest the need for additional experimental work to characterize ROPS stress levels during staged overturns and during testing according to the SAE standard.

30 CFR 7.307 - Static pressure test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static pressure test. 7.307 Section 7.307 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Motor Assemblies § 7.307 Static...

A Comparison of Quasi-Static Indentation to Low-Velocity Impact

NASA Technical Reports Server (NTRS)

Nettles, A. T.; Douglas, M. J.

2000-01-01

A static test method for modeling low-velocity foreign object impact events to composites would prove to be very beneficial to researchers since much more data can be obtained from a static test than from an impact test. In order to examine if this is feasible, a series of static indentation and low-velocity impact tests were carried out and compared. Square specimens of many sizes and thicknesses were utilized to cover the array of types of low velocity impact events. Laminates with a pi/4 stacking sequence were employed since this is by far the most common type of engineering laminate. Three distinct flexural rigidities -under two different boundary conditions were tested in order to obtain damage ranging from that due to large deflection to contact stresses and levels in-between to examine if the static indentation-impact comparisons are valid under the spectrum of damage modes that can be experienced. Comparisons between static indentation and low-velocity impact tests were based on the maximum applied transverse load. The dependent parameters examined included dent depth, back surface crack length, delamination area, and to a limited extent, load-deflection behavior. Results showed that no distinct differences could be seen between the static indentation tests and the low-velocity impact tests, indicating that static indentation can be used to represent a low-velocity impact event.

Non-animal methodologies within biomedical research and toxicity testing.

PubMed

Knight, Andrew

2008-01-01

Laboratory animal models are limited by scientific constraints on human applicability, and increasing regulatory restrictions, driven by social concerns. Reliance on laboratory animals also incurs marked - and in some cases, prohibitive - logistical challenges, within high-throughput chemical testing programmes, such as those currently underway within Europe and the US. However, a range of non-animal methodologies is available within biomedical research and toxicity testing. These include: mechanisms to enhance the sharing and assessment of existing data prior to conducting further studies, and physicochemical evaluation and computerised modelling, including the use of structure-activity relationships and expert systems. Minimally-sentient animals from lower phylogenetic orders or early developmental vertebral stages may be used, as well as microorganisms and higher plants. A variety of tissue cultures, including immortalised cell lines, embryonic and adult stem cells, and organotypic cultures, are also available. In vitro assays utilising bacterial, yeast, protozoal, mammalian or human cell cultures exist for a wide range of toxic and other endpoints. These may be static or perfused, and may be used individually, or combined within test batteries. Human hepatocyte cultures and metabolic activation systems offer potential assessment of metabolite activity and organ-organ interaction. Microarray technology may allow genetic expression profiling, increasing the speed of toxin detection, well prior to more invasive endpoints. Enhanced human clinical trials utilising micro- dosing, staggered dosing, and more representative study populations and durations, as well as surrogate human tissues, advanced imaging modalities and human epidemiological, sociological and psycho- logical studies, may increase our understanding of illness aetiology and pathogenesis, and facilitate the development of safe and effective pharmacologic interventions. Particularly when human tissues are used, non-animal models may generate faster, cheaper results, more reliably predictive for humans, whilst yielding greater insights into human biochemical processes. Greater commitment to their development and implementation is necessary, however, to efficiently meet the needs of high-throughput chemical testing programmes, important emerging testing needs, and the ongoing development of human clinical interventions.

Development of phytotoxicity indexes and their correlation with ecotoxicological, stability and physicochemical parameters during passive composting of poultry manure.

PubMed

Young, Brian Jonathan; Rizzo, Pedro Federico; Riera, Nicolás Iván; Torre, Virginia Della; López, Valeria Alejandra; Molina, Cecilia Denisse; Fernández, Florencia Estefanía; Crespo, Diana Cristina; Barrena, Raquel; Komilis, Dimitrios; Sánchez, Antoni

2016-08-01

Both raw and composted poultry manure is applied as soil amendment. The aims of this study were: (1) to develop phytotoxicity indexes for organic wastes and composts, and (2) to assess the correlation among phytotoxicity indexes, ecotoxicological endpoints and stability and physicochemical parameters during passive composting of poultry manure. Six 2-m(3) composting piles were constructed and four parameter groups (physicochemical and microbiological parameters, ecotoxicological endpoints, and biological activity) were determined at four sampling times during 92days. Extracts were used to carry out acute toxicity tests on Daphnia magna, Lactuca sativa and Raphanus sativus. Composting decreased average toxicity 22.8% for the 3 species and D. magna was the most sensitive species. The static respiration index decreased from 1.12 to 0.46mgO2gOMh(-1) whilst organic matter reduced by 64.1% at the end of the process. Escherichia coli colonies remained higher than values recommended by international guidelines. The D. magna immobilization test allowed the assessment of possible leachate or run-off toxicity. The new phytotoxicity indexes (RGIC0.8 and GIC80%), proposed in this study, as well as salinity, proved to be good maturity indicators. Hence, these phytotoxicity indexes could be implemented in monitoring strategies as useful ecotoxicological tools. Multivariate analyses demonstrated positive correlations between ecotoxicological endpoints (low toxicity) and biological activity (stability). These two parameter groups were associated at the final sampling time and showed negative correlations with several physicochemical parameters (organic and inorganic contents). The final poultry manure compost was rendered stable, but immature and, thus, unsuitable for soil amending. Copyright © 2016 Elsevier Ltd. All rights reserved.

Technical Evaluation Motor No. 10 (TEM-10)

NASA Technical Reports Server (NTRS)

1993-01-01

Technical Evaluation Motor No. 10 (TEM-10) was static fired on 27 Apr. 1993 at the Thiokol Corporation full-scale motor static test bay, T-24. This final test report documents the procedures, performance, and results of the static test firing of TEM-10. All observations, discussions, conclusions, and recommendations contained are final. Included is a presentation and discussion of TEM-10 performance, anomalies, and test results in concurrence with the objectives outlined in CTP-0110, Revision D, Space Shuttle Technical Evaluation Motor No. 10 (TEM-10) Static Fire Test Plan.

Wind-Tunnel Tests of Seven Static-Pressure Probes at Transonic Speeds

NASA Technical Reports Server (NTRS)

Capone, Francis J.

1961-01-01

Wind-tunnel tests have been conducted to determine the errors of 3 seven static-pressure probes mounted very close to the nose of a body of revolution simulating a missile forebody. The tests were conducted at Mach numbers from 0.80 to 1.08 and at angles of attack from -1.7 deg to 8.4 deg. The test Reynolds number per foot varied from 3.35 x 10(exp 6) to 4.05 x 10(exp 6). For three 4-vane, gimbaled probes, the static-pressure errors remained constant throughout the test angle-of-attack range for all Mach numbers except 1.02. For two single-vane, self-rotating probes having two orifices at +/-37.5 deg. from the plane of symmetry on the lower surface of the probe body, the static-pressure error varied as much as 1.5 percent of free-stream static pressure through the test angle-of- attack range for all Mach numbers. For two fixed, cone-cylinder probes of short length and large diameter, the static-pressure error varied over the test angle-of-attack range at constant Mach numbers as much as 8 to 10 percent of free-stream static pressure.

Toxicity of Vascular Disrupting Chemicals to Developing Zebrafish

EPA Science Inventory

Vascular development is integral to proper embryonic development and disruption of that process can have serious developmental consequences. We performed static 48-hr exposures of transgenic TG(kdr:EGFP)s843 zebrafish (Danio rerio) embryos with the known vascular inhibitors Vatal...

Assessing and monitoring the ecotoxicity of pulp and paper wastewater for irrigating reed fields using the polyurethane foam unit method based on monitoring protozoal communities.

PubMed

Ding, Cheng; Chen, Tianming; Li, Zhaoxia; Yan, Jinlong

2015-05-01

Using the standardized polyurethane foam unit (PFU) method, a preliminary investigation was carried out on the bioaccumulation and the ecotoxic effects of the pulp and paper wastewater for irrigating reed fields. Static ectoxicity test had shown protozoal communities were very sensitive to variations in toxin time and effective concentration (EC) of the pulp and paper wastewater. Shannon-Wiener diversity index (H) was a more suitable indicator of the extent of water pollution than Gleason and Margalef diversity index (d), Simpson's diversity index (D), and Pielou's index (J). The regression equation between S eq and EC was S eq  = - 0.118EC + 18.554. The relatively safe concentration and maximum acceptable toxicant concentration (MATC) of the wastewater for the protozoal communities were about 20 % and 42 %, respectively. To safely use this wastewater for irrigation, more than 58 % of the toxins must be removed or diluted by further processing. Monitoring of the wastewater in representative irrigated reed fields showed that the regularity of the protozoal colonization process was similar to the static ectoxicity, indicating that the toxicity of the irrigating pulp and paper wastewater was not lethal to protozoal communities in the reed fields. This study demonstrated the applicability of the PFU method in monitoring the ecotoxic effects of pulp and paper wastewater on the level of microbial communities and may guide the supervision and control of pulp and paper wastewater irrigating within the reed fields ecological system (RFES).

Influences on copper bioaccumulation, growth, and survival of the midge, Chironomus tentans, in metal-contaminated sediments

USGS Publications Warehouse

Besser, John M.; Kubitz, Jody A.; Ingersoll, Chris G.; Braselton, W. Emmett; Giesy, John P.

1995-01-01

Sediment bioassays with larvae of the midge, Chironomus tentans, were used to evaluate influences on the bioavailability and toxicity of copper (Cu) in sediments with a wide range of concentrations of metals, acid-volatile sulfide (AVS), and other physicochemical characteristics. Sediments were collected from sixteen lakes in Michigan, USA, and from twelve sites in the Clark Fork River drainage of Montana, USA, which are contaminated with metals from mining activities and from other anthropogenic sources. Bioassays with C. tentans larvae were conducted for ten days in a static-renewal test system, with endpoints of survival, growth, and metal bioaccumulation. Bioaccumulation of copper (Cu) was strongly correlated with Cu concentrations in porewater, and was increased significantly at Cu concentrations less than those affecting growth or survival. Midge survival and growth were not significantly correlated with concentrations of Cu in sediment or porewater, and were poorly predicted by ratios of acid-extractable metals to AVS in sediments. Principal components analysis indicated that Cu concentrations in porewater and bioaccumulation of Cu by midge larvae were influenced by AVS, sediment organic carbon, and porewater pH, and that toxicity was associated with high concentrations of Cu, high concentrations of zinc (Zn) and ammonia. No toxicity was observed in several sediments which contained low concentrations of AVS and high concentrations of Cu and Zn. In sediments which contain little AVS, bioavailability of metals may be controlled by constituents other than sulfides, such as organic matter and metal hydrous oxides. These results indicate that assessments of toxicity in metal-contaminated sediments should evaluate the importance of metal-binding phases other than sulfides, and the possible contributions of ammonia or other toxicants to toxicity in sediment bioassays.

Indentation-flexure and low-velocity impact damage in graphite/epoxy laminates

NASA Technical Reports Server (NTRS)

Kwon, Young S.; Sankar, Bhavani V.

1992-01-01

Static indentation and low velocity impact tests were performed on quasi-isotropic and cross ply graphite/epoxy composite laminates. The load deflection relations in static tests and impact force history in the impact tests were recorded. The damage was assessed by using ultrasonic C-scanning and photomicrographic techniques. The static behavior of the laminates and damage progression during loading, unloading, and reloading were explained by a simple plate delamination model. A good correlation existed between the static and impact responses. It was found that results from a few static indentation-flexture tests can be used to predict the response and damage in composite laminates due to a class of low velocity impact events.

Space Shuttle Flight Support Motor no. 1 (FSM-1)

NASA Technical Reports Server (NTRS)

Hughes, Phil D.

1990-01-01

Space Shuttle Flight Support Motor No. 1 (FSM-1) was static test fired on 15 Aug. 1990 at the Thiokol Corporation Static Test Bay T-24. FSM-1 was a full-scale, full-duration static test fire of a redesigned solid rocket motor. FSM-1 was the first of seven flight support motors which will be static test fired. The Flight Support Motor program validates components, materials, and manufacturing processes. In addition, FSM-1 was the full-scale motor for qualification of Western Electrochemical Corporation ammonium perchlorate. This motor was subjected to all controls and documentation requirements CTP-0171, Revision A. Inspection and instrumentation data indicate that the FSM-1 static test firing was successful. The ambient temperature during the test was 87 F and the propellant mean bulk temperature was 82 F. Ballistics performance values were within the specified requirements. The overall performance of the FSM-1 components and test equipment was nominal.

LLNL small-scale static spark machine: static spark sensitivity test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foltz, M F; Simpson, L R

1999-08-23

Small-scale safety testing of explosives and other energetic materials is done in order to determine their sensitivity to various stimuli, such as friction, static spark, and impact. Typically this testing is done to discover potential handling problems that may exist for either newly synthesized materials of unknown behavior, or materials that have been stored for long periods of time. This report describes the existing ''Static Spark Test Apparatus'' at Lawrence Livermore National Laboratory (LLNL), as well as the method used to evaluate the relative static spark sensitivity of energetic materials. The basic design, originally developed by the Picatinny Arsenal inmore » New Jersey, is discussed. The accumulated data for the materials tested to date is not included here, with the exception of specific examples that have yielded interesting or unusual results during the tests.« less

Technical Evaluation Motor No. 7 (TEM-07)

NASA Technical Reports Server (NTRS)

Hugh, Phil

1991-01-01

Technical Evaluation Motor Number 7 (TEM-7) was a full scale, full-duration static test firing of a high performance motor (HPM) configuration solid rocket motor (SRM) with nozzle vectoring. The static test fire occurred on 11 December 1990 at the Thiokol Corporation Static Test Bay T-97. Documented here are the procedures, performance, and results available through 22 January 1991. Critical post test hardware activities and assessment of the test data are not complete. A completed test report will be submitted 60 days after the test date. Included here is a presentation and discussion of the TEM-7 performance, anomalies, and test result concurrence with the objectives outlined in CTP-0107 Revision A, Space Shuttle Technical Evaluation Motor number 7 (TEM-07) Static Fire Test Plan.

Metal speciation and toxicity of Tamar Estuary water to larvae of the Pacific oyster, Crassostrea gigas.

PubMed

Money, Cathryn; Braungardt, Charlotte B; Jha, Awadhesh N; Worsfold, Paul J; Achterberg, Eric P

2011-07-01

As part of the PREDICT Tamar Workshop, the toxicity of estuarine waters in the Tamar Estuary (southwest England) was assessed by integration of metal speciation determination with bioassays. High temporal resolution metal speciation analysis was undertaken in situ by deployment of a Voltammetric In situ Profiling (VIP) system. The VIP detects Cd (cadmium), Pb (lead) and Cu (copper) species smaller than 4 nm in size and this fraction is termed 'dynamic' and considered biologically available. Cadmium was mainly present in the dynamic form and constituted between 56% and 100% of the total dissolved concentration, which was determined subsequently in the laboratory in filtered discrete samples. In contrast, the dynamic Pb and Cu fractions were less important, with a much larger proportion of these metals associated with organic ligands and/or colloids (45-90% Pb and 46-85% Cu), which probably reduced the toxicological impact of these elements in this system. Static toxicity tests, based on the response of Crassostrea gigas larva exposed to discrete water samples showed a high level of toxicity (up to 100% abnormal development) at two stations in the Tamar, particularly during periods of the tidal cycle when the influence of more pristine coastal water was at its lowest. Competitive ligand-exchange Cu titrations showed that natural organic ligands reduced the free cupric ion concentration to levels that were unlikely to have been the sole cause of the observed toxicity. Nonetheless, it is probable that the combined effect of the metals determined in this work contributed significantly to the bioassay response. Copyright © 2011 Elsevier Ltd. All rights reserved.

Toxicological evaluation of the effects of waste-to-energy ash-concrete on two marine species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamilton, K.L.; Nelson, W.G.; Curley, J.L.

1993-10-01

The toxicological effects of waste-to-energy ash-concrete on survivorship, growth, and fecundity (end-point parameters) of Mysidopsis bahia and on survivorship and growth of Menidia beryllina were evaluated with the 7-d static-renewal toxicity test. Leachate and elutriate solutions were prepared from experimental ash-concrete test cylinders constructed from concrete with additions of either bottom ash (mix BA), mixed bottom ash and scrubber residue, or mixed bottom ash and fly ash (60:40%, mix BA:FA). Control experiments with concrete (without ash) and pH (7-9.5) were conducted to assess any toxic effects of the stabilization process. pH did not affect end-point parameters of Mysidopsis bahia ormore » Menidia beryllina. However, the 100% elutriate solution made from concrete reduced survivorship of Mysidopsis bahia. For experiments with ash-concrete test cylinders with the BA mixture, 10-d leachate solution reduced survivorship of Mysidopsis bahia and the 100% elutriate solutions reduced survivorship of Mysidopsis bahia and Manidia beryllina. With the BA:SR mixture, the 100 and 50% elutriate solutions reduced survivorship of Menidia beryllina. The BA:FA 10- and 5-d leachate solutions and the 100, 50, and 25% elutriate solutions reduced survivorship of Menidia beryllina. The BA:FA 10- and 5-d leachate solutions and the 100, 50, 25% elutriate solutions reduced survivorship of Mysidopsis bahia.« less

24. "GAFFTC 29 SEP 60, F106B STATIC TEST 1." Test ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. "G-AFFTC 29 SEP 60, F-106B STATIC TEST 1." Test of the Convair sled escape system at static test site east of Station "50". File no. 11,988-60. - Edwards Air Force Base, South Base Sled Track, Edwards Air Force Base, North of Avenue B, between 100th & 140th Streets East, Lancaster, Los Angeles County, CA

Development and validation of an OECD reproductive toxicity test guideline with the pond snail Lymnaea stagnalis (Mollusca, Gastropoda).

PubMed

Ducrot, Virginie; Askem, Clare; Azam, Didier; Brettschneider, Denise; Brown, Rebecca; Charles, Sandrine; Coke, Maïra; Collinet, Marc; Delignette-Muller, Marie-Laure; Forfait-Dubuc, Carole; Holbech, Henrik; Hutchinson, Thomas; Jach, Arne; Kinnberg, Karin L; Lacoste, Cédric; Le Page, Gareth; Matthiessen, Peter; Oehlmann, Jörg; Rice, Lynsey; Roberts, Edward; Ruppert, Katharina; Davis, Jessica Elphinstone; Veauvy, Clemence; Weltje, Lennart; Wortham, Ruth; Lagadic, Laurent

2014-12-01

The OECD test guideline development program has been extended in 2011 to establish a partial life-cycle protocol for assessing the reproductive toxicity of chemicals to several mollusk species, including the great pond snail Lymnaea stagnalis. In this paper, we summarize the standard draft protocol for a reproduction test with this species, and present inter-comparison results obtained in a 56-day prevalidation ring-test using this protocol. Seven European laboratories performed semi-static tests with cultured snails of the strain Renilys® exposed to nominal concentrations of cadmium chloride (from 53 to 608μgCdL(-1)). Cd concentrations in test solutions were analytically determined to confirm accuracy in the metal exposure concentrations in all laboratories. Physico-chemical and biological validity criteria (namely dissolved oxygen content >60% ASV, water temperature 20±1°C, control snail survival >80% and control snail fecundity >8 egg-masses per snail over the test period) were met in all laboratories which consistently demonstrated the reproductive toxicity of Cd in snails using the proposed draft protocol. Effect concentrations for fecundity after 56days were reproducible between laboratories (68

Flight evaluation of an engine static pressure noseprobe in an F-15 airplane

NASA Technical Reports Server (NTRS)

Foote, C. H.; Jaekel, R. F.

1981-01-01

The flight testing of an inlet static pressure probe and instrumented inlet case produced results consistent with sea-level and altitude stand testing. The F-15 flight test verified the basic relationship of total to static pressure ratio versus corrected airflow and automatic distortion downmatch with the engine pressure ratio control mode. Additionally, the backup control inlet case statics demonstrated sufficient accuracy for backup control fuel flow scheduling, and the station 6 manifolded production probe was in agreement with the flight test station 6 tota pressure probes.

Successful Outcomes of a Clinical Decision Support System in an HIV Practice: A Randomized Controlled Trial

PubMed Central

Robbins, Gregory K.; Lester, William; Johnson, Kristin L.; Chang, Yuchiao; Estey, Gregory; Surrao, Dominic; Zachary, Kimon; Lammert, Sara M.; Chueh, Henry; Meigs, James B.; Freedberg, Kenneth A.

2013-01-01

Background Data to support improved patient outcomes from clinical decision support systems (CDSS) are lacking in HIV care. Objective To conduct a randomized controlled trial testing the efficacy of a CDSS to improve HIV outcomes in an outpatient clinic. Design We conducted a randomized controlled trial where half of each provider’s patients were randomized to interactive or static computer alerts (ClinicalTrials.gov #NCT00678600). Setting The study was conducted at the Massachusetts General Hospital HIV Clinic. Subjects Participants were HIV providers and their HIV-infected patients. Intervention Computer alerts were generated for virologic failure (HIV RNA >400 c/mL after HIV RNA ≤400 c/mL), evidence of suboptimal follow-up, and 11 abnormal laboratory tests. Providers received interactive computer alerts, facilitating appointment rescheduling and repeat laboratory testing, for half of their patients and static alerts for the other half. Measurements The primary endpoint was change in CD4 count. Other endpoints included time-to-clinical event, 6-month suboptimal follow-up, and severe laboratory toxicity. Results Thirty-three HIV providers followed 1,011 HIV-infected patients. For the intervention arm, the mean CD4 count increase was greater (5.3 versus 3.2 cells/mm3/month; difference = 2.0 cells/mm3/month 95% CI [0.1, 4.0], p=0.040) and the rate of 6-month suboptimal follow-up was lower (20.6 versus 30.1 events per 100 patient-years, p=0.022). Median time-to-next scheduled appointment was shorter in the intervention arm after a suboptimal follow-up alert (1.71 versus 3.48 months; p<0.001) and after a toxicity alert (2.79 versus >6 months for control); p=0.072). Ninety-six percent of providers supported adopting the CDSS as part of standard care. Limitations This was a one-year informatics study conducted at a single hospital sub-specialty clinic. Conclusion A CDSS using interactive provider alerts improved CD4 counts and clinic follow-up for HIV-infected patients. Wider implementation of such systems can provide important clinical benefits. PMID:23208165

22. STATIC TEST TOWER VIEW OF TEST CELLS AND F1 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. STATIC TEST TOWER VIEW OF TEST CELLS AND F-1 TEST LOCK DOWN FOR ENGINE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Evaluation of Relationship between Trunk Muscle Endurance and Static Balance in Male Students

PubMed Central

Barati, Amirhossein; SafarCherati, Afsaneh; Aghayari, Azar; Azizi, Faeze; Abbasi, Hamed

2013-01-01

Purpose Fatigue of trunk muscle contributes to spinal instability over strenuous and prolonged physical tasks and therefore may lead to injury, however from a performance perspective, relation between endurance efficient core muscles and optimal balance control has not been well-known. The purpose of this study was to examine the relationship of trunk muscle endurance and static balance. Methods Fifty male students inhabitant of Tehran university dormitory (age 23.9±2.4, height 173.0±4.5 weight 70.7±6.3) took part in the study. Trunk muscle endurance was assessed using Sørensen test of trunk extensor endurance, trunk flexor endurance test, side bridge endurance test and static balance was measured using single-limb stance test. A multiple linear regression analysis was applied to test if the trunk muscle endurance measures significantly predicted the static balance. Results There were positive correlations between static balance level and trunk flexor, extensor and lateral endurance measures (Pearson correlation test, r=0.80 and P<0.001; r=0.71 and P<0.001; r=0.84 and P<0.001, respectively). According to multiple regression analysis for variables predicting static balance, the linear combination of trunk muscle endurance measures was significantly related to the static balance (F (3,46) = 66.60, P<0.001). Endurance of trunk flexor, extensor and lateral muscles were significantly associated with the static balance level. The regression model which included these factors had the sample multiple correlation coefficient of 0.902, indicating that approximately 81% of the variance of the static balance is explained by the model. Conclusion There is a significant relationship between trunk muscle endurance and static balance. PMID:24800004

8. STATIC TEST TOWER NORTHWEST ELEVATION FROM THE POWER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. STATIC TEST TOWER - NORTHWEST ELEVATION FROM THE POWER PLANT TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Static and Wind Tunnel Aero-Performance Tests of NASA AST Separate Flow Nozzle Noise Reduction Configurations

NASA Technical Reports Server (NTRS)

Mikkelsen, Kevin L.; McDonald, Timothy J.; Saiyed, Naseem (Technical Monitor)

2001-01-01

This report presents the results of cold flow model tests to determine the static and wind tunnel performance of several NASA AST separate flow nozzle noise reduction configurations. The tests were conducted by Aero Systems Engineering, Inc., for NASA Glenn Research Center. The tests were performed in the Channels 14 and 6 static thrust stands and the Channel 10 transonic wind tunnel at the FluiDyne Aerodynamics Laboratory in Plymouth, Minnesota. Facility checkout tests were made using standard ASME long-radius metering nozzles. These tests demonstrated facility data accuracy at flow conditions similar to the model tests. Channel 14 static tests reported here consisted of 21 ASME nozzle facility checkout tests and 57 static model performance tests (including 22 at no charge). Fan nozzle pressure ratio varied from 1.4 to 2.0, and fan to core total pressure ratio varied from 1.0 to 1.19. Core to fan total temperature ratio was 1.0. Channel 10 wind tunnel tests consisted of 15 tests at Mach number 0.28 and 31 tests at Mach 0.8. The sting was checked out statically in Channel 6 before the wind tunnel tests. In the Channel 6 facility, 12 ASME nozzle data points were taken and 7 model data points were taken. In the wind tunnel, fan nozzle pressure ratio varied from 1.73 to 2.8, and fan to core total pressure ratio varied from 1.0 to 1.19. Core to fan total temperature ratio was 1.0. Test results include thrust coefficients, thrust vector angle, core and fan nozzle discharge coefficients, total pressure and temperature charging station profiles, and boat-tail static pressure distributions in the wind tunnel.

Residual strength and crack propagation tests on C-130 airplane center wings with service-imposed fatigue damage

NASA Technical Reports Server (NTRS)

Snider, H. L.; Reeder, F. L.; Dirkin, W. J.

1972-01-01

Fourteen C-130 airplane center wings, each containing service-imposed fatigue damage resulting from 4000 to 13,000 accumulated flight hours, were tested to determine their fatigue crack propagation and static residual strength characteristics. Eight wings were subjected to a two-step constant amplitude fatigue test prior to static testing. Cracks up to 30 inches long were generated in these tests. Residual static strengths of these wings ranged from 56 to 87 percent of limit load. The remaining six wings containing cracks up to 4 inches long were statically tested as received from field service. Residual static strengths of these wings ranged from 98 to 117 percent of limit load. Damage-tolerant structural design features such as fastener holes, stringers, doublers around door cutouts, and spanwise panel splices proved to be effective in retarding crack propagation.

33 CFR 156.170 - Equipment tests and inspections.

Code of Federal Regulations, 2014 CFR

2014-07-01

... distort under static liquid pressure at least 11/2 times the maximum allowable working pressure; and (iv... static liquid pressure test is successfully completed in the presence of the COTP. The test medium is not... static liquid pressure at least 11/2 times the maximum allowable working pressure; and (5) Each item of...

33 CFR 156.170 - Equipment tests and inspections.

Code of Federal Regulations, 2012 CFR

2012-07-01

... distort under static liquid pressure at least 11/2 times the maximum allowable working pressure; and (iv... static liquid pressure test is successfully completed in the presence of the COTP. The test medium is not... static liquid pressure at least 11/2 times the maximum allowable working pressure; and (5) Each item of...

33 CFR 156.170 - Equipment tests and inspections.

Code of Federal Regulations, 2013 CFR

2013-07-01

... distort under static liquid pressure at least 11/2 times the maximum allowable working pressure; and (iv... static liquid pressure test is successfully completed in the presence of the COTP. The test medium is not... static liquid pressure at least 11/2 times the maximum allowable working pressure; and (5) Each item of...

20. UNCOVERED TEST CELL AT THE STATIC TEST TOWER ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. UNCOVERED TEST CELL AT THE STATIC TEST TOWER ON THE WEST SIDE WHERE F-1 ENGINE WAS TESTED. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

A New Technique Using Low Volumes: A New Technique to Assess the Molluscicidal Activity Using Low Volumes.

PubMed

Santos, José Augusto Albuquerque; Cavalcante, Viviane Paixão; Rangel, Leonardo da Silva; Leite, João Claudio Vitória Atico; Faria, Robson Xavier

2017-01-01

Schistosomiasis is a disease endemic in several states of Brazil. The population control of the transmitter mollusks is done with Bayluscide WP 70®, in the control programs. OMS preconize molluscicidal assays using Becker with 500 mL of final volume, restringing the number of natural products and synthetic drugs to be tested in function of high quantity of material necessary. A new technique to assess the toxic effects for Biomphalaria sp. is the purpose of this work, for developing adaptation for this aquatic organism, using a low volume of test solution in 24-well plates. We used Biomphalaria glabrata (10-12 mm size) in a static system, consisting of the following components: Becker containing 10 snails or 24-well plates where snails were individualized for a volume of 2 mL per well for 24 and 48 hours. For the assays, we added aqueous solutions of Bayluscide WP 70, at a concentration of 1-5 mg/L, distilled water, and 1% dimethyl sulfoxide. Data were evaluated using Kappa's coefficient, Z factor validation, and comparison study. This technique to assess the toxic effect has proven to be a useful tool to detect lethal and sublethal effects, which could be used as a new evaluation protocol.

A New Technique Using Low Volumes: A New Technique to Assess the Molluscicidal Activity Using Low Volumes

PubMed Central

Cavalcante, Viviane Paixão; Rangel, Leonardo da Silva; Leite, João Claudio Vitória Atico

2017-01-01

Schistosomiasis is a disease endemic in several states of Brazil. The population control of the transmitter mollusks is done with Bayluscide WP 70®, in the control programs. OMS preconize molluscicidal assays using Becker with 500 mL of final volume, restringing the number of natural products and synthetic drugs to be tested in function of high quantity of material necessary. A new technique to assess the toxic effects for Biomphalaria sp. is the purpose of this work, for developing adaptation for this aquatic organism, using a low volume of test solution in 24-well plates. We used Biomphalaria glabrata (10–12 mm size) in a static system, consisting of the following components: Becker containing 10 snails or 24-well plates where snails were individualized for a volume of 2 mL per well for 24 and 48 hours. For the assays, we added aqueous solutions of Bayluscide WP 70, at a concentration of 1–5 mg/L, distilled water, and 1% dimethyl sulfoxide. Data were evaluated using Kappa's coefficient, Z factor validation, and comparison study. This technique to assess the toxic effect has proven to be a useful tool to detect lethal and sublethal effects, which could be used as a new evaluation protocol. PMID:28951760

Equipment and Protocols for Quasi-Static and Dynamic Tests of Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC)

DTIC Science & Technology

2016-08-01

quasi -static mechanical properties, deformation behavior, and damage mechanisms in HSHDC and compare the behavior with VHSC. 2. Develop experimental ...using the experimental setup described in Chapter 6. The quasi -static strain rate was approximately 10-4/s. All panels tested have nominal dimensions...ER D C TR -1 6- 13 Force Protection Basing; TeCD 1a Equipment and Protocols for Quasi -Static and Dynamic Tests of Very-High-Strength

Toxic effects of NH4+-N on embryonic development of Bufo gargarizans and Rana chensinensis.

PubMed

Deng, Hongzhang; Chai, Lihong; Luo, Pingping; Zhou, Meimei; Nover, Daniel; Zhao, Xiaohong

2017-09-01

Although nitrogen fertilizer is commonly used worldwide, little information is currently available about NH 4 + -N toxicity on amphibians. This study determined the acute and chronic toxic effects of NH 4 + -N on two native Chinese amphibian species (Bufo gargarizans and Rana chensinensis), and compared the negative sensitivity of different embryos to NH 4 + -N. Static renewal aqueous exposures were performed using B. gargarizans and R. chensinensis embryos at Gosner stage 2 over 96 h. In terms of 96 h-LC 50 , B. gargarizans and R. chensinensis embryos had significantly different responses to NH 4 + -N, and the latter was more sensitive to NH 4 + -N than the former. In the chronic toxicity test, exposure to 10 mg L -1 NH 4 + -N or higher significantly decreased the hatching rate of embryos in both species. Significant increases in the abnormality rate of embryos at 50 mg L -1 NH 4 + -N or higher were observed and morphological abnormalities were characterized by axial flexures, yolk sac edema, and hyperplasia in both species. Additionally, the total length of embryos decreased in a dose-dependent manner after exposure to NH 4 + -N. The results indicate that NH 4 + -N exposure can increase abnormality and inhibit the hatching and development of embryos in B. gargarizans and R. chensinensis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Response of sago pondweed, a submerged aquatic macrophyte, to herbicides in three laboratory culture systems

USGS Publications Warehouse

Fleming, W.J.; Ailstock, M.S.; Momot, J.J.; Norman, C.M.; Gorsuch, Joseph W.; Lower, William R.; Wang, Wun-cheng; Lewis, M.A.

1991-01-01

The phytotoxicity of atrazine, paraquat, glyphosate, and alachlor to sago pondweed (Potamogeton pectinatus), a submerged aquatic macrophyte, was tested under three types of laboratory culture conditions. In each case, tests were conducted in static systems, the test period was four weeks, and herbicide exposure was chronic, resulting from a single addition of herbicide to the test vessels at the beginning of the test period. The three sets of test conditions employed were(1) axenic cultures in 125-mL flasks containing a nutrient media and sucrose; (2) a microcosm system employing 18.9-L buckets containing a sand, shell, and peat substrate; and (3) an algae-free system employing O.95-L jars containing reconstituted freshwater and a nutrient agar substrate. The primary variable measured was biomass production. Plants grew well in all three test systems, with biomass of untreated plants increasing by a factor of about 5 to 6.5 during the four-week test period. Biomass production in response to herbicide exposure differed significantly among culture systems, which demonstrates the need for a standardized testing protocol for evaluating the effects of toxics on submerged aquatic plants.

Progression of hydroxychloroquine toxic effects after drug therapy cessation: new evidence from multimodal imaging.

PubMed

Mititelu, Mihai; Wong, Brandon J; Brenner, Marie; Bryar, Paul J; Jampol, Lee M; Fawzi, Amani A

2013-09-01

Given the infrequent occurrence of hydroxychloroquine toxic effects, few data are available about the presenting features and long-term follow-up of patients with hydroxychloroquine retinopathy, making it difficult to surmise the clinical course of patients after cessation of drug treatment. To report functional and structural findings of hydroxychloroquine retinal toxic effects after drug therapy discontinuation. A retrospective medical record review was performed to identify patients taking hydroxychloroquine who were screened for toxic effects from January 1, 2009, through August 31, 2012, in the eye centers of Northwestern University and the University of Southern California. Northwestern University Sorrel Rosin Eye Center, Chicago, Illinois, and the Doheny Eye Institute at the University of Southern California, Los Angeles. Seven consecutive patients diagnosed as having hydroxychloroquine retinal toxic effects. Retinal toxic effects. Seven patients (1 man and 6 women) with a mean age of 55.9 years (age range, 25-74 years) developed retinal toxic effects after using hydroxychloroquine for a mean of 10.4 years (range, 3-19 years). Fundus examination revealed macular pigmentary changes in all 7 patients, corresponding to abnormal fundus autofluorescence (FAF). On spectral domain optical coherence tomography, there was outer retinal foveal resistance (preservation of the external limiting membrane and the photoreceptor layer) in 6 patients. After drug therapy discontinuation, 5 patients experienced outer retinal regeneration (3 subfoveally and 2 parafoveally), with associated functional visual improvement on static perimetry in 2 patients. Over time, FAF remained stable in 3 patients, whereas the remaining patients had a pattern of hypoautofluorescence that replaced areas of initial hyperautofluorescence (2 patients) and enlargement of the total area of abnormal FAF (2 patients). Preservation of the external limiting membrane carries a positive prognostic value in hydroxychloroquine toxic effects because it may be associated with regeneration of the photoreceptor layer and with potential functional visual improvement on static perimetry. The patterns of abnormal FAF persist despite cessation of the medication, with enlargement of the total area of abnormal FAF being the hallmark of severe toxic effects. Relative foveal resistance in hydroxychloroquine toxic effects was supported by this case series. These findings emphasize the importance of early detection and the need for correlating clinical observations with multimodal imaging, particularly FAF and spectral domain optical coherence tomography.

18. STATIC TEST TOWER VIEW FROM REMOVABLE LEVEL DOWN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. STATIC TEST TOWER - VIEW FROM REMOVABLE LEVEL DOWN TOWARDS GANTRY CRANE AND THREE TEST CELLS. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

VIEW OF EAST TEST SITE FROM TOP OF STATIC TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF EAST TEST SITE FROM TOP OF STATIC TEST TOWER VIEW INCLUDES STRUCTURAL DYNAMICS TEST STAND COLD CALIBRATION TEST STAND AND COMPONENTS TEST LAB. - Marshall Space Flight Center, East Test Area, Dodd Road, Huntsville, Madison County, AL

Effect of somatosensory and neurofeedback training on balance in older healthy adults: a preliminary investigation.

PubMed

Azarpaikan, Atefeh; Taheri Torbati, Hamidreza

2017-10-23

The aim of this study was to assess the effectiveness of balance training with somatosensory and neurofeedback training on dynamic and static balance in healthy, elderly adults. The sample group consisted of 45 healthy adults randomly assigned to one of the three test groups: somatosensory, neurofeedback, and a control. Individualization of the balance program started with pre-tests for static and dynamic balances. Each group had 15- and 30-min training sessions. All groups were tested for static (postural stability) and dynamic balances (Berg Balance Scale) in acquisition and transfer tests (fall risk of stability and timed up and go). Improvements in static and dynamic balances were assessed by somatosensory and neurofeedback groups and then compared with the control group. Results indicated significant improvements in static and dynamic balances in both test groups in the acquisition test. Results revealed a significant improvement in the transfer test in the neurofeedback and somatosensory groups, in static and dynamic conditions, respectively. The findings suggest that these methods of balance training had a significant influence on balance. Both the methods are appropriate to prevent falling in adults. Neurofeedback training helped the participants to learn static balance, while somatosensory training was effective on dynamic balance learning. Further research is needed to assess the effects of longer and discontinuous stimulation with somatosensory and neurofeedback training on balance in elderly adults.

Evaluation of Geosynthetic-Reinforced Flexible Pavements using Static Plate Load Tests

DOT National Transportation Integrated Search

2010-01-01

This study focuses on the response of full-scale geogrid-reinforced flexible pavements to static surface loading. Specifically, static plate load (SPL) tests were performed on a low-volume, asphalt pavement frontage road in Eastern Arkansas, USA (the...

Development and validation of an OECD reproductive toxicity test guideline with the mudsnail Potamopyrgus antipodarum (Mollusca, Gastropoda).

PubMed

Ruppert, Katharina; Geiß, Cornelia; Askem, Clare; Benstead, Rachel; Brown, Rebecca; Coke, Maira; Ducrot, Virginie; Egeler, Philipp; Holbech, Henrik; Hutchinson, Thomas H; Kinnberg, Karin L; Lagadic, Laurent; Le Page, Gareth; Macken, Ailbhe; Matthiessen, Peter; Ostermann, Sina; Schimera, Agnes; Schmitt, Claudia; Seeland-Fremer, Anne; Smith, Andy J; Weltje, Lennart; Oehlmann, Jörg

2017-08-01

Mollusks are known to be uniquely sensitive to a number of reproductive toxicants including some vertebrate endocrine disrupting chemicals. However, they have widely been ignored in environmental risk assessment procedures for chemicals. This study describes the validation of the Potamopyrgus antipodarum reproduction test within the OECD Conceptual Framework for Endocrine Disrupters Testing and Assessment. The number of embryos in the brood pouch and adult mortality serve as main endpoints. The experiments are conducted as static systems in beakers filled with artificial medium, which is aerated trough glass pipettes. The test chemical is dispersed into the medium, and adult snails are subsequently introduced into the beakers. After 28 days the reproductive success is determined by opening the brood pouch and embryo counting. This study presents the results of two validation studies of the reproduction test with eleven laboratories and the chemicals tributyltin (TBT) with nominal concentrations ranging from 10 to 1000 ng TBT-Sn/L and cadmium with concentrations from 1.56 to 25 μg/L. The test design could be implemented by all laboratories resulting in comparable effect concentrations for the endpoint number of embryos in the brood pouch. After TBT exposure mean EC 10 , EC 50 , NOEC and LOEC were 35.6, 127, 39.2 and 75.7 ng Sn/L, respectively. Mean effect concentrations in cadmium exposed snails were, respectively, 6.53, 14.2, 6.45 and 12.6 μg/L. The effect concentrations are in good accordance with already published data. Both validation studies show that the reproduction test with P. antipodarum is a well-suited tool to assess reproductive effects of chemicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

VIEW OF EAST TEST SITE FROM TOP OF STATIC TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF EAST TEST SITE FROM TOP OF STATIC TEST TOWER VIEW INCLUDES POWER PLANT TEST STAND AND SATURN V TEST STAND IN THE WEST TEST AREA (FAR BACKGROUND). - Marshall Space Flight Center, East Test Area, Dodd Road, Huntsville, Madison County, AL

Characterization of Space Shuttle Reusable Rocket Motor Static Test Stand Thrust Measurements

NASA Technical Reports Server (NTRS)

Cook, Mart L.; Gruet, Laurent; Cash, Stephen F. (Technical Monitor)

2003-01-01

Space Shuttle Reusable Solid Rocket Motors (RSRM) are static tested at two ATK Thiokol Propulsion facilities in Utah, T-24 and T-97. The newer T-97 static test facility was recently upgraded to allow thrust measurement capability. All previous static test motor thrust measurements have been taken at T-24; data from these tests were used to characterize thrust parameters and requirement limits for flight motors. Validation of the new T-97 thrust measurement system is required prior to use for official RSRM performance assessments. Since thrust cannot be measured on RSRM flight motors, flight motor measured chamber pressure and a nominal thrust-to-pressure relationship (based on static test motor thrust and pressure measurements) are used to reconstruct flight motor performance. Historical static test and flight motor performance data are used in conjunction with production subscale test data to predict RSRM performance. The predicted motor performance is provided to support Space Shuttle trajectory and system loads analyses. Therefore, an accurate nominal thrust-to-pressure (F/P) relationship is critical for accurate RSRM flight motor performance and Space Shuttle analyses. Flight Support Motors (FSM) 7, 8, and 9 provided thrust data for the validation of the T-97 thrust measurement system. The T-97 thrust data were analyzed and compared to thrust previously measured at T-24 to verify measured thrust data and identify any test-stand bias. The T-97 FIP data were consistent and within the T-24 static test statistical family expectation. The FSMs 7-9 thrust data met all NASA contract requirements, and the test stand is now verified for future thrust measurements.

13. TOP OF STATIC TEST TOWER VIEW OF STEEL TRUSS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. TOP OF STATIC TEST TOWER VIEW OF STEEL TRUSS STRUCTURE AND OVERHEAD CRANE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Comparative effects of pH and Vision herbicide on two life stages of four anuran amphibian species.

PubMed

Edginton, Andrea N; Sheridan, Patrick M; Stephenson, Gerald R; Thompson, Dean G; Boermans, Herman J

2004-04-01

Vision, a glyphosate-based herbicide containing a 15% (weight:weight) polyethoxylated tallow amine surfactant blend, and the concurrent factor of pH were tested to determine their interactive effects on early life-stage anurans. Ninety-six-hour laboratory static renewal studies, using the embryonic and larval life stages (Gosner 25) of Rana clamitans, R. pipiens, Bufo americanus, and Xenopus laevis, were performed under a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach for obtaining confidence intervals. There was a significant (p < 0.05) interaction of pH with Vision concentration in all eight models, such that the toxicity of Vision was amplified by elevated pH. The surfactant is the major toxic component of Vision and is hypothesized, in this study, to be the source of the pH interaction. Larvae of B. americanus and R. clamitans were 1.5 to 3.8 times more sensitive than their corresponding embryos, whereas X. laevis and R. pipiens larvae were 6.8 to 8.9 times more sensitive. At pH values above 7.5, the Vision concentrations expected to kill 50% of the test larvae in 96-h (96-h lethal concentration [LC50]) were predicted to be below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities. The EEC value represents a worst-case scenario for aerial Vision application and is calculated assuming an application of the maximum label rate (2.1 kg acid equivalents [a.e.]/ha) into a pond 15 cm in depth. The EEC of 1.4 mg a.e./L (4.5 mg/L Vision) was not exceeded by 96-h LC50 values for the embryo test. The larvae of the four species were comparable in sensitivity. Field studies should be completed using the more sensitive larval life stage to test for Vision toxicity at actual environmental concentrations.

A Static Burst Test for Composite Flywheel Rotors

NASA Astrophysics Data System (ADS)

Hartl, Stefan; Schulz, Alexander; Sima, Harald; Koch, Thomas; Kaltenbacher, Manfred

2016-06-01

High efficient and safe flywheels are an interesting technology for decentralized energy storage. To ensure all safety aspects, a static test method for a controlled initiation of a burst event for composite flywheel rotors is presented with nearly the same stress distribution as in the dynamic case, rotating with maximum speed. In addition to failure prediction using different maximum stress criteria and a safety factor, a set of tensile and compressive tests is carried out to identify the parameters of the used carbon fiber reinforced plastics (CFRP) material. The static finite element (FE) simulation results of the flywheel static burst test (FSBT) compare well to the quasistatic FE-simulation results of the flywheel rotor using inertia loads. Furthermore, it is demonstrated that the presented method is a very good controllable and observable possibility to test a high speed flywheel energy storage system (FESS) rotor in a static way. Thereby, a much more expensive and dangerous dynamic spin up test with possible uncertainties can be substituted.

Investigation of two pitot-static tubes at supersonic speeds

NASA Technical Reports Server (NTRS)

Hasel, Lowell E; Coletti, Donald E

1948-01-01

The results of tests at a Mach number of 1.94 of an ogives-nose cylindrical pitot-static tube and similar tests at Mach numbers of 1.93 and 1.62 of a service pitot-static tube to determine body static pressures and indicated Mach numbers are presented and discussed. The radial pressure distribution on the cylindrical bodies is compared with that calculated by an approximate theory.

37. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER. THIS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER. THIS VIEW SHOWS TWO MAJOR CHANGES TO THE STATIC TEST TOWER: THE ADDITION OF THE NASA LOGO TO THE FACADE AND THE ADDITION OF THE UPPER STAGES TO THE JUPITER MISSILE IN THE WEST POSITION ON THE TOWER TO REPRESENT THE JUNO II CONFIGURATION. 1961, PHOTOGRAPHER UNKNOWN, FRED ORDWAY COLLECTION, U. S. SPACE AND ROCKET CENTER, HUNTSVILLE, AL. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

24. CLOSEUP OF MOUNT FOR F1 ENGINE ON STATIC TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. CLOSE-UP OF MOUNT FOR F-1 ENGINE ON STATIC TEST TOWER WITH STRUCTURAL DYNAMICS TEST STAND IN DISTANCE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Failure mechanics in low-velocity impacts on thin composite plates

NASA Technical Reports Server (NTRS)

Elber, W.

1983-01-01

Eight-ply quasi-isotropic composite plates of Thornel 300 graphite in Narmco 5208 epoxy resin (T300/5208) were tested to establish the degree of equivalence between low-velocity impact and static testing. Both the deformation and failure mechanics under impact were representable by static indentation tests. Under low-velocity impacts such as tool drops, the dominant deformation mode of the plates was the first, or static, mode. Higher modes are excited on contact, but they decay significantly by the time the first-mode load reaches a maximum. The delamination patterns were observed by X-ray analysis. The areas of maximum delamination patterns were observed by X-ray analysis. The areas of maximum delamination coincided with the areas of highest peel stresses. The extent of delamination was similar for static and impact tests. Fiber failure damage was established by tensile tests on small fiber bundles obtained by deplying test specimens. The onset of fiber damage was in internal plies near the lower surface of the plates. The distribution and amount of fiber damage was similar fo impact and static tests.

38. 100,000 POUND STATIC TEST FACILITY: GENERAL VIEW OF TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

38. 100,000 POUND STATIC TEST FACILITY: GENERAL VIEW OF TEST BAY AND EXHAUST PIT, LOOKING WEST - White Sands Missile Range, V-2 Rocket Facilities, Near Headquarters Area, White Sands, Dona Ana County, NM

37. 100,000 POUND STATIC TEST FACILITY: GENERAL VIEW OF TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. 100,000 POUND STATIC TEST FACILITY: GENERAL VIEW OF TEST BAY AND EXHAUST PIT, LOOKING SOUTHWEST - White Sands Missile Range, V-2 Rocket Facilities, Near Headquarters Area, White Sands, Dona Ana County, NM

Technical Evaluation Motor no. 5 (TEM-5)

NASA Technical Reports Server (NTRS)

Cook, M.

1990-01-01

Technical Evaluation Motor No. 5 (TEM-5) was static test fired at the Thiokol Corporation Static Test Bay T-97. TEM-5 was a full scale, full duration static test fire of a high performance motor (HPM) configuration solid rocket motor (SRM). The primary purpose of TEM static tests is to recover SRM case and nozzle hardware for use in the redesigned solid rocket motor (RSRM) flight program. Inspection and instrumentation data indicate that the TEM-5 static test firing was successful. The ambient temperature during the test was 41 F and the propellant mean bulk temperature (PMBT) was 72 F. Ballistics performance values were within the specified requirements. The overall performance of the TEM-5 components and test equipment was nominal. Dissembly inspection revealed that joint putty was in contact with the inner groove of the inner primary seal of the ignitor adapter-to-forward dome (inner) joint gasket; this condition had not occurred on any previous static test motor or flight RSRM. While no qualification issues were addressed on TEM-5, two significant component changes were evaluated. Those changes were a new vented assembly process for the case-to-nozzle joint and the installation of two redesigned field joint protection systems. Performance of the vented case-to-nozzle joint assembly was successful, and the assembly/performance differences between the two field joint protection system (FJPS) configurations were compared.

Some observations on loss of static strength due to fatigue cracks

NASA Technical Reports Server (NTRS)

Illg, Walter; Hardrath, Herbert F

1955-01-01

Static tensile tests were performed on simple notched specimens containing fatigue cracks. Four types of aluminum alloys were investigated: 2024-T3(formerly 24S-T3) and 7075-T6(formerly 75S-T6) in sheet form, and 2024-T4(formerly 24S-T4) and 7075-T6(formerly 75S-T6) in extruded form. The cracked specimens were tested statically under four conditions: unmodified and with reduced eccentricity of loading by three methods. Results of static tests on C-46 wings containing fatigue cracks are also reported.

Toxicity of the Herbicide Atrazine: Effects on Lipid Peroxidation and Activities of Antioxidant Enzymes in the Freshwater Fish Channa Punctatus (Bloch)

PubMed Central

Nwani, Christopher Ddidigwu; Lakra, Wazir Singh; Nagpure, Naresh Sahebrao; Kumar, Ravindra; Kushwaha, Basdeo; Srivastava, Satish Kumar

2010-01-01

The present study was undertaken to evaluate the toxicity and effects of a commercial formulation of the herbicide atrazine (Rasayanzine) on lipid peroxidation and antioxidant enzyme system in the freshwater air breathing fish Channa punctatus. The 12, 24, 48, 72 and 96 h LC50 of atrazine, calculated by probit analysis, were determined to be 77.091, 64.053, 49.100, 44.412 and 42.381 mg·L−1, respectively, in a semi static system with significant difference (p < 0.05) in LC10–90 values obtained for different times of exposure. In addition to concentration and time dependent decrease in mortality rate, stress signs in the form of behavioral changes were also observed in response to the test chemical. In fish exposed for 15 days to different sublethal concentrations of the herbicide (1/4 LC50 = ∼10.600 mg·L−1, 1/8 LC50 = ∼5.300 mg·L−1 and 1/10 LC50 = ∼4.238 mg·L−1) induction of oxidative stress in the liver was evidence by increased lipid peroxidation levels. The antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) responded positively in a concentration dependent pattern, thus, suggesting the use of these antioxidants as potential biomarkers of toxicity associated with contaminations exposure in freshwater fishes. PMID:20948961

Balance Performance Is Task Specific in Older Adults.

PubMed

Dunsky, Ayelet; Zeev, Aviva; Netz, Yael

2017-01-01

Balance ability among the elderly is a key component in the activities of daily living and is divided into two types: static and dynamic. For clinicians who wish to assess the risk of falling among their elderly patients, it is unclear if more than one type of balance test can be used to measure their balance impairment. In this study, we examined the association between static balance measures and two dynamic balance field tests. One hundred and twelve community-dwelling older adults (mean age 74.6) participated in the study. They underwent the Tetrax static postural assessment and then performed the Timed Up and Go (TUG) and the Functional Reach (FR) Test as dynamic balance tests. In general, low-moderate correlations were found between the two types of balance tests. For women, age and static balance parameters explained 28.1-40.4% of the variance of TUG scores and 14.6-24% of the variance of FR scores. For men, age and static balance parameters explained 9.5-31.2% of the variance of TUG scores and 23.9-41.7% of the variance of FR scores. Based on our findings, it is suggested that a combination of both static and dynamic tests be used for assessing postural balance ability.

32. VIEW LOOKING EAST AT THE STATIC TEST TOWER WHILE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. VIEW LOOKING EAST AT THE STATIC TEST TOWER WHILE A JUPITER MISSILE IS BEING POSITIONED ONTO THE TEST TOWER. DATE AND PHOTOGRAPHER UNKNOWN, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

[Static posturography versus clinical tests in elderly people with vestibular pathology].

PubMed

Ortuño-Cortés, Miguel A; Martín-Sanz, Eduardo; Barona-de Guzmán, Rafael

2008-01-01

Balance can be quantified by clinical tests and through instrumental studies. The objective of this paper is to determine the correlation between static posturography and 4 clinical tests of balance in elderly people with vestibular disorders and to identify its capability to discriminate the groups studied. 60 patients with vestibular disorders and 60 healthy subjects performed 4 clinical tests (one leg standing with opened eyes, Timed Up and Go, Tinetti and Berg tests) and a static posturography analysis (NedSVE/IBV system) under 4 conditions: Romberg Test, Eyes Open (REO), Romberg Test, Eyes Closed (REC), Romberg Test on Foam with Eyes Open (RFEO), and Romberg Test on Foam with Eyes Closed (RFEC). RFEO correlated best with the clinical tests and RFEC was the worst. RFEO distinguished between healthy individuals and decompensated patients. RFEO gave the best information about postural balance in the elderly. RFEC was not useful. Static posturography can be useful to distinguish vestibular compensation status.

Martian Atmospheric Pressure Static Charge Elimination Tool

NASA Technical Reports Server (NTRS)

Johansen, Michael R.

2014-01-01

A Martian pressure static charge elimination tool is currently in development in the Electrostatics and Surface Physics Laboratory (ESPL) at NASA's Kennedy Space Center. In standard Earth atmosphere conditions, static charge can be neutralized from an insulating surface using air ionizers. These air ionizers generate ions through corona breakdown. The Martian atmosphere is 7 Torr of mostly carbon dioxide, which makes it inherently difficult to use similar methods as those used for standard atmosphere static elimination tools. An initial prototype has been developed to show feasibility of static charge elimination at low pressure, using corona discharge. A needle point and thin wire loop are used as the corona generating electrodes. A photo of the test apparatus is shown below. Positive and negative high voltage pulses are sent to the needle point. This creates positive and negative ions that can be used for static charge neutralization. In a preliminary test, a floating metal plate was charged to approximately 600 volts under Martian atmospheric conditions. The static elimination tool was enabled and the voltage on the metal plate dropped rapidly to -100 volts. This test data is displayed below. Optimization is necessary to improve the electrostatic balance of the static elimination tool.

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2014 CFR

2014-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2011 CFR

2011-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2010 CFR

2010-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2012 CFR

2012-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR 23.785 - Seats, berths, litters, safety belts, and shoulder harnesses.

Code of Federal Regulations, 2013 CFR

2013-01-01

... combination of structural analysis and static load tests to limit load; or (3) Static load tests to ultimate... OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY... resulting from the ultimate static load factors prescribed in § 23.561(b)(2) of this part. Each occupant...

14 CFR Appendix E to Part 43 - Altimeter System Test and Inspection

Code of Federal Regulations, 2011 CFR

2011-01-01

... made that would affect the relationship between air pressure in the static pressure system and true ambient static air pressure for any flight condition. (b) Altimeter: (1) Test by an appropriately rated... inspections required by § 91.411 shall comply with the following: (a) Static pressure system: (1) Ensure...

Clinical approach to optic neuropathies

PubMed Central

Behbehani, Raed

2007-01-01

Optic neuropathy is a frequent cause of vision loss encountered by ophthalmologist. The diagnosis is made on clinical grounds. The history often points to the possible etiology of the optic neuropathy. A rapid onset is typical of demyelinating, inflammatory, ischemic and traumatic causes. A gradual course points to compressive, toxic/nutritional and hereditary causes. The classic clinical signs of optic neuropathy are visual field defect, dyschromatopsia, and abnormal papillary response. There are ancillary investigations that can support the diagnosis of optic neuropathy. Visual field testing by either manual kinetic or automated static perimetry is critical in the diagnosis. Neuro-imaging of the brain and orbit is essential in many optic neuropathies including demyelinating and compressive. Newer technologies in the evaluation of optic neuropathies include multifocal visual evoked potentials and optic coherence tomography. PMID:19668477

Comparison of Quality and Output of Different Optimal Perimetric Testing Approaches in Children With Glaucoma.

PubMed

Patel, Dipesh E; Cumberland, Phillippa M; Walters, Bronwen C; Russell-Eggitt, Isabelle; Brookes, John; Papadopoulos, Maria; Khaw, Peng Tee; Viswanathan, Ananth C; Garway-Heath, David; Cortina-Borja, Mario; Rahi, Jugnoo S

2018-02-01

There is limited evidence to support the development of guidance for visual field testing in children with glaucoma. To compare different static and combined static/kinetic perimetry approaches in children with glaucoma. Cross-sectional, observational study recruiting children prospectively between May 2013 and June 2015 at 2 tertiary specialist pediatric ophthalmology centers in London, England (Moorfields Eye Hospital and Great Ormond Street Hospital). The study included 65 children aged 5 to 15 years with glaucoma (108 affected eyes). A comparison of test quality and outcomes for static and combined static/kinetic techniques, with respect to ability to quantify glaucomatous loss. Children performed perimetric assessments using Humphrey static (Swedish Interactive Thresholding Algorithm 24-2 FAST) and Octopus combined static tendency-oriented perimetry/kinetic perimetry (isopter V4e, III4e, or I4e) in a single sitting, using standardized clinical protocols, administered by a single examiner. Information was collected about test duration, completion, and quality (using automated reliability indices and our qualitative Examiner-Based Assessment of Reliability score). Perimetry outputs were scored using the Aulhorn and Karmeyer classification. One affected eye in 19 participants was retested with Swedish Interactive Thresholding Algorithm 24-2 FAST and 24-2 standard algorithms. Sixty-five children (33 girls [50.8%]), with a median age of 12 years (interquartile range, 9-14 years), were tested. Test quality (Examiner-Based Assessment of Reliability score) improved with increasing age for both Humphrey and Octopus strategies and were equivalent in children older than 10 years (McNemar test, χ2 = 0.33; P = .56), but better-quality tests with Humphrey perimetry were achieved in younger children (McNemar test, χ2 = 4.0; P = .05). Octopus and Humphrey static MD values worse than or equal to -6 dB showed disagreement (Bland-Altman, mean difference, -0.70; limit of agreement, -7.74 to 6.35) but were comparable when greater than this threshold (mean difference, -0.03; limit of agreement, -2.33 to 2.27). Visual field classification scores for static perimetry tests showed substantial agreement (linearly weighted κ, 0.79; 95% CI, 0.65-0.93), although 25 of 80 (31%) were graded with a more severe defect for Octopus static perimetry. Of the 7 severe cases of visual field loss (grade 5), 5 had lower kinetic than static classification scores. A simple static perimetry approach potentially yields high-quality results in children younger than 10 years. For children older than 10 years, without penalizing quality, the addition of kinetic perimetry enabled measurement of far-peripheral sensitivity, which is particularly useful in children with severe visual field restriction.

Using growth measures in the freshwater shrimp Caridina nilotica as biomarkers of Roundup® pollution of South African freshwater systems

NASA Astrophysics Data System (ADS)

Mensah, P. K.; Muller, W. J.; Palmer, C. G.

There has been global concern about the effect of toxic chemicals on aquatic biota due to the upsurge in contamination of aquatic ecosystems by these chemicals, which includes pesticides. Roundup® and other glyphosate-based herbicides are frequently used in the chemical control of weeds and invading alien plant species in South Africa. These bio-active chemicals ultimately get into water courses directly or indirectly through processes such as drifting, leaching, surface runoff and foliar spray of aquatic nuisance plants. However, there is no South African water quality guideline to protect indigenous freshwater non-target organisms from the toxic effects of glyphosate-based herbicides. This study evaluated the possible use of growth measures in Caridina nilotica as biomarkers of Roundup® pollution as part of developing glyphosate water quality guideline for the protection of aquatic life in South Africa. Using static-renewal methods in a 25-day growth toxicity test, 40 days post hatch shrimps were exposed to different sub-lethal Roundup® concentrations of 0.0 (control), 2.2, 2.8, 3.4, 4.3 and 5.4 mg/L. Shrimps were fed daily with TetraMin® flake food and test solutions changed every third day. Shrimp total lengths and wet weights were measured every fifth day. These data were used to determine the shrimp’s growth performance and feed utilization in terms of percent weight gain (PWG), percent length gain (PLG), specific growth rate (SGR), condition factor (CF), feed intake (FI), feed conversion ratio (FCR) and feed conversion efficiency (FCE). Moulting was observed for 14 days and the data used to determine the daily moult rate for each concentration. Results of growth performance and food utilization indices showed that growth was significantly impaired in all exposed groups compared to control (p < 0.05). Moulting frequency was also higher in all exposed groups than in control (p < 0.05). Although all the tested growth measures proved to be possible biomarkers of Roundup® pollution, moulting frequency gives a clearer indication of the sub-lethal effects of Roundup® toxicity.

Effect on fan flow characteristics of length and axial location of a cascade thrust reverser

NASA Technical Reports Server (NTRS)

Dietrich, D. A.

1975-01-01

A series of static tests were conducted on a model fan with a diameter of 14.0 cm to determine the fan operating characteristics, the inlet static pressure contours, the fan-exit total and static pressure contours, and the fan-exit pressure distortion parameters associated with the installation of a partial-circumferential-emission cascade thrust reverser. The tests variables included the cascade axial length, the axial location of the reverser, and the type of fan inlet. It was shown that significant total and static pressure distortions were produced in the fan aft duct, and that some configurations induced a static pressure distortion at the fan face. The amount of flow passed by the fan and the level of the flow distortions were dependent upon all the variables tested.

Toxicity of methanol to fish, crustacean, oligochaete worm, and aquatic ecosystem.

PubMed

Kaviraj, A; Bhunia, F; Saha, N C

2004-01-01

Static renewal bioassays were conducted in the laboratory and in outdoor artificial enclosures to evaluate toxic effects of methanol to one teleost fish and two aquatic invertebrates and to limnological variables of aquatic ecosystem. Ninety-six-hour acute toxicity tests revealed cladoceran crustacea Moina micrura as the most sensitive to methanol (LC50, 4.82 g/L), followed by freshwater teleost Oreochromis mossambicus (LC50, 15.32 g/L) and oligochaete worm Branchiura sowerbyi (LC50, 54.89 g/L). The fish, when exposed to lethal concentrations of methanol, showed difficulties in respiration and swimming. The oligochaete body wrinkled and fragmented under lethal exposure of methanol. Effects of five sublethal concentrations of methanol (0, 23.75, 47.49, 736.10, and 1527.60 mg/L) on the feeding rate of the fish and on its growth and reproduction were evaluated by separate bioassays. Ninety-six-hour bioassays in the laboratory showed significant reduction in the appetite of fish when exposed to 736.10 mg/L or higher concentrations of methanol. Chronic toxicity bioassays (90 days) in outdoor enclosures showed a reduction in growth, maturity index and fecundity of fish at 47.49 mg/L or higher concentrations of methanol. Primary productivity, phytoplankton population, and alkalinity of water were also reduced at these concentrations. Chronic exposure to 1527.60 mg/L methanol resulted in damages of the epithelium of primary and secondary gill lamellae of the fish. The results revealed 23.75 mg/L as the no-observed-effect concentration (NOEC) of methanol to freshwater aquatic ecosystem.

29. SATURN ROCKET ENGINE LOCATED ON NORTH SIDE OF STATIC ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. SATURN ROCKET ENGINE LOCATED ON NORTH SIDE OF STATIC TEST STAND - DETAILS OF THE EXPANSION NOZZLE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

GENERAL VIEW LOOKING SOUTH AT THE SATURN I STATIC TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GENERAL VIEW LOOKING SOUTH AT THE SATURN I STATIC TEST STAND. NOTE THE FIRST STAGE OF THE SATURN I ROCKET ON DISPLAY TO THE LEFT OF THE TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Static and dynamic pile testing of reinforced concrete piles with structure integrated fibre optic strain sensors

NASA Astrophysics Data System (ADS)

Schilder, Constanze; Kohlhoff, Harald; Hofmann, Detlef; Basedau, Frank; Habel, Wolfgang R.; Baeßler, Matthias; Niederleithinger, Ernst; Georgi, Steven; Herten, Markus

2013-05-01

Static and dynamic pile tests are carried out to determine the load bearing capacity and the quality of reinforced concrete piles. As part of a round robin test to evaluate dynamic load tests, structure integrated fibre optic strain sensors were used to receive more detailed information about the strains along the pile length compared to conventional measurements at the pile head. This paper shows the instrumentation of the pile with extrinsic Fabry-Perot interferometers sensors and fibre Bragg gratings sensors together with the results of the conducted static load test as well as the dynamic load tests and pile integrity tests.

Mitigating Upsets in SRAM Based FPGAs from the Xilinix Virtex 2 Family

NASA Technical Reports Server (NTRS)

Swift, Gary M.; Yui, Candice C.; Carmichael, Carl; Koga, Rocky; George, Jeffrey S.

2003-01-01

This slide presentation reviews the single event upset static testing of the Virtex II field programmable gate arrays (FPGA) that were tested in protons and heavy-ions. The test designs and static and dynamic test results are reviewed.

Pilot Study: Foam Wedge Chin Support Static Tolerance Testing

DTIC Science & Technology

2017-10-24

AFRL-SA-WP-SR-2017-0026 Pilot Study : Foam Wedge Chin Support Static Tolerance Testing Austin M. Fischer, BS1; William W...COVERED (From – To) April – October 2017 4. TITLE AND SUBTITLE Pilot Study : Foam Wedge Chin Support Static Tolerance Testing 5a. CONTRACT NUMBER...prototype to mitigate the increase in helmet weight and forward center of gravity. The purpose of this pilot study was to determine the feasibility and

Dynamic Breaking Tests of Airplane Parts

NASA Technical Reports Server (NTRS)

Hertel, Heinrich

1933-01-01

The static stresses of airplane parts, the magnitude of which can be determined with the aid of static load assumptions, are mostly superposed by dynamic stresses, the magnitude of which has been but little explored. The object of the present investigation is to show how the strength of airplane parts can best be tested with respect to dynamic stresses with and without superposed static loading, and to what extent the dynamic strength of the parts depends on their structural design. Experimental apparatus and evaluation methods were developed and tried for the execution of vibration-strength tests with entire structural parts both with and without superposed static loading. Altogether ten metal spars and spar pieces and two wooden spars were subjected to vibration breaking tests.

Subsonic static and dynamic stability characteristics of the test technique demonstrator NASP configuration

NASA Technical Reports Server (NTRS)

Boyden, Richmond P.; Dress, David A.; Fox, Charles H., Jr.; Huffman, Jarrett K.; Cruz, Christopher I.

1993-01-01

The paper describes the procedure used for and the results obtained of wind-tunnel tests of the National Aerospace Plane (NASP) configuration, which were conducted in the NASA Langley Research Center High Speed Tunnel using a blended body NASP configuration designed by the research center. Static and dynamic stability characteristics were measured at Mach numbers 0.3, 0.6, and 0.8. In addition to tests of the baseline configuration, component buildup tests with a canard surface and with a body flap were carried out. Results demonstrated a positive static stability of the baseline configuration, except at the higher angles of attack at Mach 0.8. A good agreement was found between the inphase dynamic parameters and the corresponding static data.

Evaluation of the attenuating properties of selected Greek clays for toxic inorganic elements in landfill sites.

PubMed

Mimides, T; Perraki, T

2000-05-15

Heavy metal attenuation properties of selected clay material collected from miscellaneous Greek sites is investigated and tested in the laboratory for their suitability, either as liners in hydrologically unsafe sites or as earth covers for sanitary landfill sites. Eleven potentially hazardous elements (As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Se, V, and Zn) generated by a co-disposal landfill leachate have been considered. Experimental column and static equilibrium methods for the determination of dispersion and adsorption are described. Molecular diffusion dominates the migration phenomena with a velocity range between 1.3 x 10(-5) and 3.5 x 10(-4) cm/s throughout the experiments. A simple way to evaluate dispersion coefficients from breakthrough curves gave values of between 3.90 x 10(-6) and 3.5 x 10(-4) cm2/s, with a mean value of 1.5 x 10(-5). Static adsorption equilibrium studies supported by column runs showed that Freundlich (F = kCn) isotherms express in a better way the assimilative capacities of the tested clays, with k and n values ranging from 0.06 to 1.99 and 0.55 to 1.48 correspondingly. Mathematical models involving non-linear parabolic equations are involved. The experimental data, together with finite difference techniques and some physical clay characteristics, produced trilinear textural diagrams and predictive flow transport convection-dispersion breakthrough curves for a quick estimation of the attenuating properties of clays for heavy metals.

Strategy for Alternative Occupant Volume Testing

DOT National Transportation Integrated Search

2009-10-20

This paper describes plans for a series of quasi-static : compression tests of rail passenger equipment. These tests are : designed to evaluate the strength of the occupant volume under : static loading conditions. The research plan includes a detail...

Bioaccumulation and Toxicity of Uranium, Arsenic and Nickel to Juveniles and Adults Hyalella azteca in Spiked Sediment Bioassays.

PubMed

Goulet, Richard R; Thompson, Patsy-A

2018-05-26

Uranium mining and milling release arsenic (As), nickel (Ni) and uranium (U) to receiving waters, which accumulate in sediments. The objective of this study was to investigate if As, Ni and U concentrations in tissue residue of Hyalella azteca, overlying water, sediment pore water and solids could predict juvenile and adult survival and growth in similar conditions to lake sediments downstream of Uranium mines and mills. We conducted 14 day, static sediment toxicity tests spiked with uranium, arsenic and nickel salts. For uranium, we spiked uranyl nitrate with sodium bicarbonate to limit U precipitation once in contact with circumneutral sediment. LC 50 for As, Ni and U of juveniles and adults based on measured concentrations in sediments were 1.8 and 2.2 µmol As/g dw, 6.3 and 13.4 µmol Ni/g dw and 0.2 and 0.9 µmol U/g dw, respectively. Adult survival and growth linearly decreased with increasing bioaccumulation. For juveniles, metal accumulation linearly predicted survival. We calculated lethal body concentrations (LBC 50 ) for juveniles and adults of 70 and 485 nmol As/g dw, 246 and 832 nmol Ni/g dw and 1.7 and 4.4 nmol U/g dw, respectively. The concentrations of As, Ni and U in tissue residue leading to a 20% decrease in growth were 427 nmol As/g, 755 nmol Ni/g and 5 nmol U/g. Overall, this study showed that Uranium was the most toxic element followed by As and Ni, that juveniles were more sensitive to the three metals tested than adults and that threshold body concentrations can support assessment of benthic invertebrate community impairment. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Dynamic and Quasi-Static Grade Crossing Collision Tests

DOT National Transportation Integrated Search

2009-03-02

To support the development of a proposed rule [1], a fullscale : dynamic test and two full-scale quasi-static tests have : been performed on the posts of a state-of-the-art (SOA) end : frame. These tests were designed to evaluate the dynamic and : qu...

Static tensile and tensile creep testing of five ceramic fibers at elevated temperatures

NASA Technical Reports Server (NTRS)

Zimmerman, Richard S.; Adams, Donald F.

1989-01-01

Static tensile and tensile creep testing of five ceramic fibers at elevated temperature was performed. J.P. Stevens, Co., Astroquartz 9288 glass fiber; Nippon Carbon, Ltd., (Dow Corning) nicalon NLM-102 silicon carbide fiber; and 3M Company Nextel 312, 380, and 480 alumina/silica/boria fibers were supplied in unsized tows. Single fibers were separated from the tows and tested in static tension and tensile creep. Elevated test temperatures ranged from 400 C to 1300 C and varied for each fiber. Room temperature static tension was also performed. Computer software was written to reduce all single fiber test data into engineering constants using ASTM Standard Test Method D3379-75 as a reference. A high temperature furnace was designed and built to perform the single fiber elevated temperature testing up to 1300 C. A computerized single fiber creep apparatus was designed and constructed to perform four fiber creep tests simultaneously at temperatures up to 1300 C. Computer software was written to acquire and reduce all creep data.

Static tensile and tensile creep testing of five ceramic fibers at elevated temperatures

NASA Technical Reports Server (NTRS)

Zimmerman, Richard S.; Adams, Donald F.

1988-01-01

Static tensile and tensile creep testing of five ceramic fibers at elevated temperature was performed. J.P. Stevens, Co., Astroquartz 9288 glass fiber, Nippon Carbon, Ltd., (Dow Corning) Nicalon NLM-102 silicon carbide fiber, and 3M Company Nextel 312, 380, and 480 alumina/silica/boria fibers were supplied in unsized tows. Single fibers were separated from the tows and tested in static tension and tensile creep. Elevated test temperatures ranged from 400 to 1300 C and varied for each fiber. Room temperature static tension was also performed. Computer software was written to reduce all single fiber test data into engineering constants using ASTM Standard Test Method D3379-75 as a reference. A high temperature furnace was designed and built to perform the single fiber elevated temperature testing up to 1300 C. A computerized single fiber creep apparatus was designed and constructed to perform four fiber creep tests simultaneously at temperatures up to 1300 C. Computer software was written to acquire and reduce all creep data.

35. VIEW LOOKING NORTHWEST AT THE STATIC TEST TOWER. A ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

35. VIEW LOOKING NORTHWEST AT THE STATIC TEST TOWER. A 'DUMMY' SATURN I BOOSTER IS BEING HOISTED INTO THE TEST STAND TO TEST THE MATING OF THE BOOSTER AND THE TEST STAND. EARLY 1960, PHOTOGRAPHER UNKNOWN, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

34. 100,000 POUND STATIC TEST FACILITY: GENERAL VIEW OF BLOCKHOUSE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

34. 100,000 POUND STATIC TEST FACILITY: GENERAL VIEW OF BLOCKHOUSE AND TOP OF TEST BAY, LOOKING NORTHEAST - White Sands Missile Range, V-2 Rocket Facilities, Near Headquarters Area, White Sands, Dona Ana County, NM

33. 100,000 POUND STATIC TEST FACILITY: GENERAL VIEW OF BLOCKHOUSE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. 100,000 POUND STATIC TEST FACILITY: GENERAL VIEW OF BLOCKHOUSE AND UPPER LEVEL OF TEST BAY, LOOKING NORTH - White Sands Missile Range, V-2 Rocket Facilities, Near Headquarters Area, White Sands, Dona Ana County, NM

Technical Evaluation Motor No. 7 (TEM-7)

NASA Technical Reports Server (NTRS)

Hughes, Phil

1991-01-01

The Technical Evaluation Motor No. 7 (TEM-7) test was a full-scale, full duration static test firing of a high performance motor-configuration solid rocket motor with nozzle vectoring. The final test report documents the procedures, performance, and results of the static test firing of TEM-7. All observations, discussions, conclusions, and recommendations included in the report are complete and final except for the TEM-7 fixed housing unbond investigation. A presentation and discussion of TEM-7 performance, anomalies, and test result concurrence with the objectives outlined in CTP-0107, Rev A, Space Shuttle Technical Evaluation Motor No. 7 (TEM-7) Static Fire Test Plan are included.

Effects of CFT Legumine (5% Rotenone) on tadpole survival and metamorphosis of Chiricahua leopard frogs Lithobates chiricahuensis, Northern leopard frogs L. pipiens, and American bullfrogs L. catesbeianus

USGS Publications Warehouse

Alvarez, Guillermo; Caldwell, Colleen A.; Kruse, Carter G.

2017-01-01

Amphibians may experience collateral effects if exposed to CFT Legumine (5% rotenone), a piscicide that is used to remove invasive fish. A series of 48-h static toxicity tests assessed the acute effects of CFT Legumine on multi-aged tadpoles of the federally listed Chiricahua leopard frog Lithobates chiricahuensis, the widespread northern leopard frog L. pipiens, and the increasingly invasive American bullfrog L. catesbeianus. At the earliest Gosner stages (GS 21–25), Chiricahua leopard frogs were more sensitive to CFT Legumine (median lethal concentration [LC50] = 0.41–0.58 mg/L) than American bullfrogs (LC50 = 0.63–0.69 mg/L) and northern leopard frogs (LC50 = 0.91 and 1.17 mg/L). As tadpoles developed (i.e., increase in GS), their sensitivity to rotenone decreased. In a separate series of 48-h static nonrenewal toxicity tests, tadpoles (GS 21–25 and GS 31–36) of all three species were exposed to piscicidal concentrations of CFT Legumine (0.5, 1.0, and 2.0 mg/L) to assess postexposure effects on metamorphosis. In survivors of all three species at both life stages, the time to tail resorption was nearly doubled in comparison with that of controls. For example, mid-age (GS 31–36) Chiricahua leopard frog tadpoles required 210.7 h to complete tail resorption, whereas controls required 108.5 h. However, because tail resorption is a relatively short period in metamorphosis, the total duration of development (days from posthatch to complete metamorphosis) and the final weight did not differ in either age-group surviving nominal concentrations of 0.5-, 1.0-, and 2.0-mg/L CFT Legumine relative to controls. This research demonstrates that the CFT Legumine concentrations commonly used in field applications to remove unwanted fish could result in considerable mortality of the earliest stages of Lithobates species. In addition to acute lethality, piscicide treatments may result in delayed tail resorption, which places the tadpoles at risk by increasing their vulnerability to predation and pathogens.

30 CFR 18.67 - Static-pressure tests.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static-pressure tests. 18.67 Section 18.67 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Inspections and Tests § 18...

Characterization of Lactobacillus brevis L62 strain, highly tolerant to copper ions.

PubMed

Mrvčić, Jasna; Butorac, Ana; Solić, Ema; Stanzer, Damir; Bačun-Družina, Višnja; Cindrić, Mario; Stehlik-Tomas, Vesna

2013-01-01

Lactic acid bacteria (LAB) as starter culture in food industry must be suitable for large-scale industrial production and possess the ability to survive in unfavorable processes and storage conditions. Approaches taken to address these problems include the selection of stress-resistant strains. In food industry, LAB are often exposed to metal ions induced stress. The interactions between LAB and metal ions are very poorly investigated. Because of that, the influence of non-toxic, toxic and antioxidant metal ions (Zn, Cu, and Mn) on growth, acid production, metal ions binding capacity of wild and adapted species of Leuconostoc mesenteroides L3, Lactobacillus brevis L62 and Lactobacillus plantarum L73 were investigated. The proteomic approach was applied to clarify how the LAB cells, especially the adapted ones, protect themselves and tolerate high concentrations of toxic metal ions. Results have shown that Zn and Mn addition into MRS medium in the investigated concentrations did not have effect on the bacterial growth and acid production, while copper ions were highly toxic, especially in static conditions. Leuc. mesenteroides L3 was the most efficient in Zn binding processes among the chosen LAB species, while L. plantarum L73 accumulated the highest concentration of Mn. L. brevis L62 was the most copper resistant species. Adaptation had a positive effect on growth and acid production of all species in the presence of copper. However, the adapted species incorporated less metal ions than the wild species. The exception was adapted L. brevis L62 that accumulated high concentration of copper ions in static conditions. The obtained results showed that L. brevis L62 is highly tolerant to copper ions, which allows its use as starter culture in fermentative processes in media with high concentration of copper ions.

33. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER DURING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER DURING A TEST OF THE PROPULSION SYSTEM OF A JUPITER MISSILE. DATE AND PHOTOGRAPHER UNKNOWN. FRED ORDWAY COLLECTION, U.S. SPACE AND ROCKET CENTER, HUNTSVILLE, AL. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Deep flaws in weldments of aluminum and titanium

NASA Technical Reports Server (NTRS)

Masters, J. N.; Engstrom, W. L.; Bixler, W. D.

1974-01-01

Surface flawed specimens of 2219-T87 and 6Al-4V STA titanium weldments were tested to determine static failure modes, failure strength, and fatigue flaw growth characteristics. Thicknesses selected for this study were purposely set at values where, for most test conditions, abrupt instability of the flaw at fracture would not be expected. Static tests for the aluminum weldments were performed at room, LN2 and LH2 temperatures. Titanium static tests for tests were performed at room and LH2 temperatures. Results of the static tests were used to plot curves relating initial flaw size to leakage- or failure-stresses (i.e. "failure" locus curves). Cyclic tests, for both materials, were then performed at room temperature, using initial flaws only slightly below the previously established failure locus for typical proof stress levels. Cyclic testing was performed on pairs of specimens, one with and one without a simulated proof test cycle. Comparisons were made then to determine the value and effect of proof testing as affected by the various variables of proof and operating stress, flaw shape, material thickness, and alloy.

40 CFR 53.65 - Test procedure: Loading test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... performing the test in § 53.62 (full wind tunnel test), § 53.63 (wind tunnel inlet aspiration test), or § 53... particle delivery system shall consist of a static chamber or a low velocity wind tunnel having a.... The mean velocity in the test section of the static chamber or wind tunnel shall not exceed 2 km/hr...

Saturn Apollo Program

NASA Image and Video Library

1963-12-05

The test laboratory of the Marshall Space Flight Center (MSFC) tested the F-1 engine, the most powerful rocket engine ever fired at MSFC. The engine was tested on the newly modified Saturn IB Static Test Stand which had been used for three years to test the Saturn I eight-engine booster, S-I (first) stage. In 1961 the test stand was modified to permit static firing of the S-I/S-IB stage and the name of the stand was then changed to the S-IB Static Test Stand. Producing a combined thrust of 7,500,000 pounds, five F-1 engines powered the S-IC (first) stage of the Saturn V vehicle for the marned lunar mission.

Saturn Apollo Program

NASA Image and Video Library

1963-12-01

The test laboratory of the Marshall Space Flight Center (MSFC) tested the F-1 engine, the most powerful rocket engine ever fired at MSFC. The engine was tested on the newly modified Saturn IB static test stand that had been used for three years to test the Saturn I eight-engine booster, S-I (first) stage. In 1961, the test stand was modified to permit static firing of the S-I/S-IB stage and the name of the stand was then changed to the S-IB Static Test Stand. Producing a combined thrust of 7,500,000 pounds, five F-1 engines powered the S-IC (first) stage of the Saturn V vehicle for the marned lunar mission.

The role of visual representation in physics learning: dynamic versus static visualization

NASA Astrophysics Data System (ADS)

Suyatna, Agus; Anggraini, Dian; Agustina, Dina; Widyastuti, Dini

2017-11-01

This study aims to examine the role of visual representation in physics learning and to compare the learning outcomes of using dynamic and static visualization media. The study was conducted using quasi-experiment with Pretest-Posttest Control Group Design. The samples of this research are students of six classes at State Senior High School in Lampung Province. The experimental class received a learning using dynamic visualization and control class using static visualization media. Both classes are given pre-test and post-test with the same instruments. Data were tested with N-gain analysis, normality test, homogeneity test and mean difference test. The results showed that there was a significant increase of mean (N-Gain) learning outcomes (p <0.05) in both experimental and control classes. The averages of students’ learning outcomes who are using dynamic visualization media are significantly higher than the class that obtains learning by using static visualization media. It can be seen from the characteristics of visual representation; each visualization provides different understanding support for the students. Dynamic visual media is more suitable for explaining material related to movement or describing a process, whereas static visual media is appropriately used for non-moving physical phenomena and requires long-term observation.

Commuter rail seat testing and analysis of facing seats

DOT National Transportation Integrated Search

2003-12-01

Tests have been conducted on the Bombardier back-to-back commuter rail car seat in a facing-seat configuration to evaluate its performance under static and dynamic loading conditions. Quasi-static tests have been conducted to establish the load defle...

The oxidized state of the nanocomposite Carbo-Iron® causes no adverse effects on growth, survival and differential gene expression in zebrafish.

PubMed

Weil, Mirco; Meißner, Tobias; Busch, Wibke; Springer, Armin; Kühnel, Dana; Schulz, Ralf; Duis, Karen

2015-10-15

For degradation of halogenated chemicals in groundwater Carbo-Iron®, a composite of activated carbon and nano-sized Fe(0), was developed (Mackenzie et al., 2012). Potential effects of this nanocomposite on fish were assessed. Beyond the contaminated zone Fe(0) can be expected to have oxidized and Carbo-Iron was used in its oxidized form in ecotoxicological tests. Potential effects of Carbo Iron in zebrafish (Danio rerio) were investigated using a 48 h embryo toxicity test under static conditions, a 96 h acute test with adult fish under semi-static conditions and a 34 d fish early life stage test (FELST) in a flow-through system. Particle diameters in test suspensions were determined via dynamic light scattering (DLS) and ranged from 266 to 497 nm. Particle concentrations were measured weekly in samples from the FELST using a method based on the count rate in DLS. Additionally, uptake of particles into test organisms was investigated using microscopic methods. Furthermore, effects of Carbo-Iron on gene expression were investigated by microarray analysis in zebrafish embryos. In all tests performed, no significant lethal effects were observed. Furthermore, Carbo-Iron had no significant influence on weight and length of fish as determined in the FELST. In the embryo test and the early life stage test, growth of fungi on the chorion was observed at Carbo-Iron concentrations between 6.3 and 25mg/L. Fungal growth did not affect survival, hatching success and growth. In the embryo test, no passage of Carbo-Iron particles into the perivitelline space or the embryo was observed. In juvenile and adult fish, Carbo-Iron was detected in the gut at the end of exposure. In juvenile fish exposed to Carbo-Iron for 29 d and subsequently kept for 5d in control water, Carbo-Iron was no longer detectable in the gut. Global gene expression in zebrafish embryos was not significantly influenced by Carbo-Iron. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of the in-flight noise signature of a 32-chute suppressor nozzle: Acoustic data report. [outdoor static and 40 x 80 ft. wind tunnel tests

NASA Technical Reports Server (NTRS)

Moore, M. T.; Doyle, V. L.

1977-01-01

Outdoor static and 40 x 80 FT wind tunnel tests of the J79-15 engine/nacelle system with the conic nozzle and 32-chute exhaust suppressor were conducted to acquire the data necessary to evaluate the simulated in-flight signature of an engine-size 32-chute exhaust nozzle suppressor using the 40 x 80 ft wind tunnel and to study possible engine core noise contamination of the jet signature. The tests are described and and a sampling of the data acquired is presented. Included are aero performance summaries, as-measured and composite 1/3 OBSPL spectra for the 70 ft sideline high and low mics from the outdoor static tests, sideline traverse spectra and internal noise measurements from both the outdoor static and the 40 x 80 ft wind tunnel tests.

Study of the influence of hole quality on composite materials

NASA Technical Reports Server (NTRS)

Pengra, J. J.

1980-01-01

The influence of hole quality on the structural behavior of composite materials was investigated. From an industry survey it was determined that the most frequent imperfections encountered during hole fabrication are chipout, delamination, and oversize conditions. These hole flaw types were generated in critical areas of static, compression, and fatigue specimens fabricated from T300/5208 graphite/epoxy system. The specimens were tested in static and cyclic pin bearing modes in addition to compression loading. Results of these tests are presented and discussed. The hole chipout defect reduced the static and cyclic endurance characteristics. Oversize holes also lowered the cyclic pin bearing endurance, but had no influence of the static pin bearing characteristics. Delamination had no insignificant influence on the static tension and cyclic pin bearing characteristics. Compression tests demonstrated a deleterious effect for chipout of delamination defects. Hole quality requirements proposed are discussed.

Crashworthiness testing of Amtrak's traditional coach seat : safety of high-speed ground transportation systems

DOT National Transportation Integrated Search

1996-10-01

Tests have been conducted on Amtrak's traditional passenger seat to evaluate its performance under static and dynamic loading conditions. Quasi-static tests have been conducted to establish the load-deflection characteristics of the seat. Dynamic tes...

A microcomputer-based testing station for dynamic and static testing of protective relay systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, W.J.; Li, R.J.; Gu, J.C.

1995-12-31

Dynamic and static relay performance testing before installation in the field is a subject of great interest to utility relay engineers. The common practice in utility testing of new relays is to put the new unit to be tested in parallel with an existing functioning relay in the system, wait until an actual transient occurs and then observe and analyze the performance of new relay. It is impossible to have a thorough test of the protective relay system through this procedure. An equipment, Microcomputer-Based Testing Station (or PC-Based Testing Station), that can perform both static and dynamic testing of themore » relay is described in this paper. The Power System Simulation Laboratory at the University of Texas at Arlington is a scaled-down, three-phase, physical power system which correlates well with the important components for a real power system and is an ideal facility for the dynamic and static testing of protective relay systems. A brief introduction to the configuration of this laboratory is presented. Test results of several protective functions by using this laboratory illustrate the usefulness of this test set-up.« less

Static tensile and tensile creep testing of four boron nitride coated ceramic fibers at elevated temperatures

NASA Technical Reports Server (NTRS)

Coguill, Scott L.; Adams, Donald F.; Zimmerman, Richard S.

1989-01-01

Six types of uncoated ceramic fibers were static tensile and tensile creep tested at various elevated temperatures. Three types of boron nitride coated fibers were also tested. Room temperature static tensile tests were initially performed on all fibers, at gage lengths of 1, 2, and 4 inches, to determine the magnitude of end effects from the gripping system used. Tests at one elevated temperature, at gage lengths of 8 and 10 inches, were also conducted, to determine end effects at elevated temperatures. Fiber cross sectional shapes and areas were determined using scanning electron microscopy. Creep testing was typically performed for 4 hours, in an air atmosphere.

Structural testing for static failure, flutter and other scary things

NASA Technical Reports Server (NTRS)

Ricketts, R. H.

1983-01-01

Ground test and flight test methods are described that may be used to highlight potential structural problems that occur on aircraft. Primary interest is focused on light-weight general aviation airplanes. The structural problems described include static strength failure, aileron reversal, static divergence, and flutter. An example of each of the problems is discussed to illustrate how the data acquired during the tests may be used to predict the occurrence of the structural problem. While some rules of thumb for the prediction of structural problems are given the report is not intended to be used explicitly as a structural analysis handbook.

Wind Tunnel Testing of Various Disk-Gap-Band Parachutes

NASA Technical Reports Server (NTRS)

Cruz, Juan R.; Mineck, Raymond E.; Keller, Donald F.; Bobskill, Maria V.

2003-01-01

Two Disk-Gap-Band model parachute designs were tested in the NASA Langley Transonic Dynamics Tunnel. The purposes of these tests were to determine the drag and static stability coefficients of these two model parachutes at various subsonic Mach numbers in support of the Mars Exploration Rover mission. The two model parachute designs were designated 1.6 Viking and MPF. These model parachute designs were chosen to investigate the tradeoff between drag and static stability. Each of the parachute designs was tested with models fabricated from MIL-C-7020 Type III or F-111 fabric. The reason for testing model parachutes fabricated with different fabrics was to evaluate the effect of fabric permeability on the drag and static stability coefficients. Several improvements over the Viking-era wind tunnel tests were implemented in the testing procedures and data analyses. Among these improvements were corrections for test fixture drag interference and blockage effects, and use of an improved test fixture for measuring static stability coefficients. The 1.6 Viking model parachutes had drag coefficients from 0.440 to 0.539, while the MPF model parachutes had drag coefficients from 0.363 to 0.428. The 1.6 Viking model parachutes had drag coefficients 18 to 22 percent higher than the MPF model parachute for equivalent fabric materials and test conditions. Model parachutes of the same design tested at the same conditions had drag coefficients approximately 11 to 15 percent higher when manufactured from F-111 fabric as compared to those fabricated from MIL-C-7020 Type III fabric. The lower fabric permeability of the F-111 fabric was the source of this difference. The MPF model parachutes had smaller absolute statically stable trim angles of attack as compared to the 1.6 Viking model parachutes for equivalent fabric materials and test conditions. This was attributed to the MPF model parachutes larger band height to nominal diameter ratio. For both designs, model parachutes fabricated from F-111 fabric had significantly greater statically stable absolute trim angles of attack at equivalent test conditions as compared to those fabricated from MILC-7020 Type III fabric. This reduction in static stability exhibited by model parachutes fabricated from F-111 fabric was attributed to the lower permeability of the F-111 fabric. The drag and static stability coefficient results were interpolated to obtain their values at Mars flight conditions using total porosity as the interpolating parameter.

30 CFR 7.307 - Static pressure test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Motor Assemblies § 7.307 Static...) Permanent deformation exceeding 0.040 inches per linear foot; or (iii) Clearances, in excess of those...

30 CFR 7.307 - Static pressure test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Motor Assemblies § 7.307 Static...) Permanent deformation exceeding 0.040 inches per linear foot; or (iii) Clearances, in excess of those...

30 CFR 7.307 - Static pressure test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Motor Assemblies § 7.307 Static...) Permanent deformation exceeding 0.040 inches per linear foot; or (iii) Clearances, in excess of those...

30 CFR 7.307 - Static pressure test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Motor Assemblies § 7.307 Static...) Permanent deformation exceeding 0.040 inches per linear foot; or (iii) Clearances, in excess of those...

Embedded data collector (EDC) phase II load and resistance factor design (LRFD).

DOT National Transportation Integrated Search

2015-09-01

A total of 16 static load test results was collected in Florida and Louisiana. New static load tests on five test piles : in Florida (four of which were voided) were monitored with Embedded Data Collector (EDC) instrumentation and : contributed to th...

Study on the interactions between toxic nitroanilines and lysozyme by spectroscopic approaches and molecular modeling.

PubMed

Gu, Yunlan; Wang, Yanqing; Zhang, Hongmei

2018-05-05

Being exogenous environmental pollutants, nitroanilines (NAs) are highly toxic and have mutagenic and carcinogenic activity. Being lack of studies on interactions between NAs and lysozyme at molecular level, the binding interactions of lysozyme with o-nitroaniline (oNA), m-nitroaniline (mNA) and p-nitroaniline (pNA) were investigated by means of steady-state fluorescence, synchronous fluorescence, UV-vis absorption spectroscopy, as well as molecular modeling. The experimental results revealed that the fluorescence of lysozyme is quenched by oNA and mNA through a static quenching, while the fluorescence quenching triggered by pNA is a combined dynamic and static quenching. The number of binding sites (n) and the binding constant (K b ) corresponding thermodynamic parameters ΔH ⊖ , ΔS ⊖ , ΔG ⊖ at different temperatures were calculated. The reactions between NAs and lysozyme were spontaneous and entropy driven and the binding of NAs to lysozyme induced conformation changes of lysozyme. The difference of the position of -NO 2 group affected the binding and the binding constants K b decreased in the following pattern: K b (pNA) >K b (mNA) >K b (oNA). Molecular docking studies were performed to reveal the most favorable binding sites of NAs on lysozyme. Our recently results could offer mechanistic insights into the nature of the binding interactions between NAs and lysozyme and provide information about the toxicity risk of NAs to human health. Copyright © 2018 Elsevier B.V. All rights reserved.

Theoretical research and experimental validation of quasi-static load spectra on bogie frame structures of high-speed trains

NASA Astrophysics Data System (ADS)

Zhu, Ning; Sun, Shou-Guang; Li, Qiang; Zou, Hua

2014-12-01

One of the major problems in structural fatigue life analysis is establishing structural load spectra under actual operating conditions. This study conducts theoretical research and experimental validation of quasi-static load spectra on bogie frame structures of high-speed trains. The quasistatic load series that corresponds to quasi-static deformation modes are identified according to the structural form and bearing conditions of high-speed train bogie frames. Moreover, a force-measuring frame is designed and manufactured based on the quasi-static load series. The load decoupling model of the quasi-static load series is then established via calibration tests. Quasi-static load-time histories, together with online tests and decoupling analysis, are obtained for the intermediate range of the Beijing—Shanghai dedicated passenger line. The damage consistency calibration of the quasi-static discrete load spectra is performed according to a damage consistency criterion and a genetic algorithm. The calibrated damage that corresponds with the quasi-static discrete load spectra satisfies the safety requirements of bogie frames.

Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

PubMed Central

Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

2011-01-01

This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility.

PubMed

Wong, Del P; Chaouachi, Anis; Lau, Patrick W C; Behm, David G

2011-01-01

This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key pointsThe duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001).No significant differences in RSA and COD between the 3 stretching conditions.The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects.The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments.

40. 500,000 POUND STATIC TEST FACILITY: DISTANT VIEW WITH BLOCKHOUSE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

40. 500,000 POUND STATIC TEST FACILITY: DISTANT VIEW WITH BLOCKHOUSE IN FOREGROUND, LOOKING SOUTHEAST - White Sands Missile Range, V-2 Rocket Facilities, Near Headquarters Area, White Sands, Dona Ana County, NM

40 CFR Table F-2 to Subpart F of... - Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test F Table F-2 to Subpart F... Part 53—Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test Primary Partical Mean Size a (µm) Full Wind Tunnel Test 2 km/hr 24 km/hr Inlet...

40 CFR Table F-2 to Subpart F of... - Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test F Table F-2 to Subpart F... Part 53—Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test Primary Partical Mean Size a (µm) Full Wind Tunnel Test 2 km/hr 24 km/hr Inlet...

40 CFR Table F-2 to Subpart F of... - Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test F Table F-2 to Subpart F... Part 53—Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test Primary Partical Mean Size a (µm) Full Wind Tunnel Test 2 km/hr 24 km/hr Inlet...

Rectifier cabinet static breaker

DOEpatents

Costantino, Jr, Roger A.; Gliebe, Ronald J.

1992-09-01

A rectifier cabinet static breaker replaces a blocking diode pair with an SCR and the installation of a power transistor in parallel with the latch contactor to commutate the SCR to the off state. The SCR serves as a static breaker with fast turnoff capability providing an alternative way of achieving reactor scram in addition to performing the function of the replaced blocking diodes. The control circuitry for the rectifier cabinet static breaker includes on-line test capability and an LED indicator light to denote successful test completion. Current limit circuitry provides high-speed protection in the event of overload.

Effects of terbutryn on aufwuchs and Lumbriculus variegatus in artificial indoor streams.

PubMed

Brust, K; Licht, O; Hultsch, V; Jungmann, D; Nagel, R

2001-09-01

The effects of the herbicide terbutryn on a simple lotic food web were investigated during a 72-d exposure period in five artificial indoor streams in a greenhouse. The model compound terbutryn, an s-triazine and an inhibitor of photosynthesis, was applied once in each stream at nominal concentrations of 0.6, 6, 60, or 600 microg/L. Terbutryn concentrations in the water were analyzed by gas chromatography/mass spectrometry, and an overall time to 50% dissipation (DT50) of 28 d was calculated. The development of aufwuchs and the population growth and development of the oligochaete Lumbriculus variegatus were investigated. We determined that terbutryn was toxic to L. variegatus at 23.7 mg/L (96-h median lethal concentration [LC50]) and 16.5 mg/L (96-h median effective concentration [EC50]) in static acute toxicity tests. Terbutryn decreased aufwuchs production at 0.6 microg/L in the experimental streams. Population growth of L. variegatus was decreased by 50% at 6 microg/L. The effect of terbutryn on the aufwuchs was a direct effect of decreases in the periphyton. However, the effects on L. variegatus were an indirect effect of terbutryn as a consequence of decrease in the aufwuchs food source and occurred at three-orders-of-magnitude-lower concentrations of terbutryn than the acute toxicity effects. Our study demonstrates the utility of indoor lotic microcosm studies for evaluating both direct and indirect effects of contaminants on aquatic ecosystems.

Effects of the herbicide imazapyr on juvenile Oregon spotted frogs

USGS Publications Warehouse

Yahnke, Amy E.; Grue, Christian E.; Hayes, Marc P.; Troiano, Alexandra T.

2013-01-01

Conflict between native amphibians and aquatic weed management in the Pacific Northwest is rarely recognized because most native stillwater-breeding amphibian species move upland during summer, when herbicide application to control weeds in aquatic habitats typically occurs. However, aquatic weed management may pose a risk for aquatic species present in wetlands through the summer, such as the Oregon spotted frog (OSF, Rana pretiosa), a state endangered species in Washington. Acute toxicity of herbicides used to control aquatic weeds tends to be low, but the direct effects of herbicide tank mixes on OSFs have remained unexamined. We exposed juvenile OSFs to tank mixes of the herbicide imazapyr, a surfactant, and a marker dye in a 96-h static-renewal test. The tank mix was chosen because of its low toxicity to fish and its effectiveness in aquatic weed control. Concentrations were those associated with low-volume (3.5 L/ha) and high-volume (7.0 L/ha) applications of imazapyr and a clean-water control. Following exposure, frogs were reared for two months in clean water to identify potential latent effects on growth. Endpoints evaluated included feeding behavior, growth, and body and liver condition indices. We recorded no mortalities and found no significant differences for any end point between the herbicide-exposed and clean-water control frogs. The results suggest that imazapyr use in wetland restoration poses a low risk of direct toxic effects on juvenile OSFs.

Acute toxicity of organochlorine insecticide endosulfan to the giant freshwater prawn Macrobrochium rosenbergii

NASA Astrophysics Data System (ADS)

Dai, Xilin; Xiong, Zhaodi; Xie, Jian; Ding, Fujiang

2014-01-01

Endosulfan, an organochlorine pesticide, is highly toxic and effective at controlling pests in agriculture, horticulture, and public health programs. In this study, static bioassays were used to evaluate the toxicity of endosulfan to freshwater prawns ( Macrobrachium rosenbergii) of various lengths (1.5±0.03, 4±0.08, and 7±0.06 cm). Additionally, the activities of peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase, acetylcholinesterase (AChE), and Na+/K+-ATPase were analyzed to reflect the effects of endosulfan exposure. The 96 h LC50 of endosulfan for prawns 1.5, 4, and 7 cm long were 1.86, 4.53, and 6.09 μg/L, respectively, improved tolerance to endosulfan with growth. The POD activities of test organisms exposed to low concentrations of endosulfan were inhibited, indicating the presence of oxygen damaged tissue. Moreover, a notable decrease in AChE activity was observed due to overstimulation of neurotransmission, which might result in abnormal behavior. The effect caused by endosulfan on phosphatase production in the hepatopancreas of prawns 1.5, 4, and 7 cm long was different because the ability of nonspecific immune regulation increased with growth. The 96 h LC50 values obtained in this study could be used in the formulation of water-quality criteria in China. Moreover, the changes in enzymes activities of M. rosenbergii under stress of endosulfan could be applied in the establishment of early warning indicators for bio-safety.

Advanced manufacturing development of a composite empennage component for L-1011 aircraft. Phase 4: Full scale ground test

NASA Technical Reports Server (NTRS)

Jackson, A. C.; Dorwald, F.

1982-01-01

The ground tests conducted on the advanced composite vertical fin (ACVF) program are described. The design and fabrication of the test fixture and the transition structure, static test of Ground Test Article (GTA) No. 1, rework of GTA No. 2, and static, damage tolerance, fail-safe and residual strength tests of GTA No. 2 are described.

Millennials in the Fire Service: The Effectiveness of Fire Service Recruiting, Testing, and Retention

DTIC Science & Technology

2017-12-01

to effectively attract and retain millennials is in question. Stale marketing and static testing processes may be contributing to smaller hiring pools...ABSTRACT Modern-day fire service methods’ ability to effectively attract and retain millennials is in question. Stale marketing and static testing... Marketing of the Testing Process ..............................................................50  Table 6.  Type of Testing Process

Effects of Antiparasitic Treatment on Dynamically and Statically Tested Cognitive Skills over Time

ERIC Educational Resources Information Center

Grigorenko, Elena L.; Sternberg, Robert J.; Jukes, Mathew; Alcock, Katie; Lambo, Jane; Ngorosho, Damaris; Nokes, Catherine; Bundy, Donald A.

2006-01-01

The main objective of this work was to investigate two testing procedures, repeated static tests and dynamic testing, that can more clearly demonstrate the impact of treatment for parasites in children. Rural Tanzanian children were assessed for the presence/absence and burden of helminth parasites and assigned to one of three…

Characterization of Friction Joints Subjected to High Levels of Random Vibration

NASA Technical Reports Server (NTRS)

deSantos, Omar; MacNeal, Paul

2012-01-01

This paper describes the test program in detail including test sample description, test procedures, and vibration test results of multiple test samples. The material pairs used in the experiment were Aluminum-Aluminum, Aluminum- Dicronite coated Aluminum, and Aluminum-Plasmadize coated Aluminum. Levels of vibration for each set of twelve samples of each material pairing were gradually increased until all samples experienced substantial displacement. Data was collected on 1) acceleration in all three axes, 2) relative static displacement between vibration runs utilizing photogrammetry techniques, and 3) surface galling and contaminant generation. This data was used to estimate the values of static friction during random vibratory motion when "stick-slip" occurs and compare these to static friction coefficients measured before and after vibration testing.

Static strain and vibration characteristics of a metal semimonocoque helicopter tail cone of moderate size

NASA Technical Reports Server (NTRS)

Bielawa, Richard L.; Hefner, Rachel E.; Castagna, Andre

1991-01-01

The results are presented of an analytic and experimental research program involving a Sikorsky S-55 helicopter tail cone directed ultimately to the improved structural analysis of airframe substructures typical of moderate sized helicopters of metal semimonocoque construction. Experimental static strain and dynamic shake-testing measurements are presented. Correlation studies of each of these tests with a PC-based finite element analysis (COSMOS/M) are described. The tests included static loadings at the end of the tail cone supported in the cantilever configuration as well as vibrational shake-testing in both the cantilever and free-free configurations.

Saturn Apollo Program

NASA Image and Video Library

1967-09-09

This photograph depicts the F-1 engine firing in the Marshall Space Flight Center’s F-1 Engine Static Test Stand. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. It is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base, designed to assist in the development of the F-1 Engine. Capability is provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. The foundation of the stand is keyed into the bedrock approximately 40 feet below grade.

Developmental effects of mercury on Etheostoma caeruleum and E. spectabile: Predictable biomarkers of stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharp, J.R.

1995-12-31

Etheostoma caeruleum and E. spectabile are sympatric teleostean species of the Family Percidae. The ova diameters and incubation times are different: E. caeruleum (1.9mm and 12-d), E. spectabile (1.2mm and 8-d). For both species, cleavage stage (4--8 cell), mid-blastula, mid-neurula, and early-eye stage embryos were exposed to + {minus}1 a 24-h static-renewal test of 0, 10, 20, 40, 60, 80, 100 {micro}gHg {sup ++}L{sup {minus}1} to assess the effects of stage-specific initial mercury exposure on the embryo-larval responses. In addition, cleavage stage embryos were exposed to a 1-d, 2-d, and 4-d static-renewal toxicity test to determine the influence that exposuremore » duration to mercury has on embryolarval responses. Five replicates of 10 embryos each were incubated at 18 C for each concentration and exposure variation. Embryos were allowed to develop until all had hatched or died. Four embryonic responses were assessed for each species and exposure protocol: 96-h LC50, AB50, SH50 and VH50. The typical nonstressor specific terata were noted for each species with an increase in percent of embryos expressing abnormal developmental patterns with increase mercury concentrations and severity of exposure. These included dwarfism, cephalic complications, ophthalmic abnormalities, cardiovascular abnormalities, various edema, and haemorrhagia. Hatching success and viability of hatch were likewise reduced with increasing severity of exposure and mercury concentration. Previously undetected terata that were observed in the first hatch included scoliosis, lordosis, kyphosis, synarthrodic jaws, and grossly enlarged yolk sacs.« less

Instance Analysis for the Error of Three-pivot Pressure Transducer Static Balancing Method for Hydraulic Turbine Runner

NASA Astrophysics Data System (ADS)

Weng, Hanli; Li, Youping

2017-04-01

The working principle, process device and test procedure of runner static balancing test method by weighting with three-pivot pressure transducers are introduced in this paper. Based on an actual instance of a V hydraulic turbine runner, the error and sensitivity of the three-pivot pressure transducer static balancing method are analysed. Suggestions about improving the accuracy and the application of the method are also proposed.

Damage and fracture in fabric-reinforced composites under quasi-static and dynamic bending

NASA Astrophysics Data System (ADS)

Ullah, H.; Harland, A. R.; Silberschmidt, V. V.

2013-07-01

Fabric-reinforced polymer composites used in sports products can be exposed to different in-service conditions such as large deformations caused by quasi-static and dynamic loading. Composite materials subjected to such bending loads can demonstrate various damage modes - matrix cracking, delamination and, ultimately, fabric fracture. Damage evolution in composites affects both their in-service properties and performance that can deteriorate with time. Such behaviour needs adequate means of analysis and investigation, the main approaches being experimental characterisation and non-destructive examination of internal damage in composite laminates. This research deals with a deformation behaviour and damage in carbon fabric-reinforced polymer (CFRP) laminates caused by quasi-static and dynamic bending. Experimental tests were carried out to characterise the behaviour of a CFRP material under large-deflection bending, first in quasi-static and then in dynamic conditions. Izod-type impact bending tests were performed on un-notched specimens of CFRP using a Resil impactor to assess the transient response and energy absorbing capability of the material. X-ray micro computed tomography (micro-CT) was used to analyse various damage modes in the tested specimens. X-ray tomographs revealed that through-thickness matrix cracking, inter-ply and intra-ply delamination such as tow debonding, and fabric fracture were the prominent damage modes both in quasi-static and dynamic test specimens. However, the inter-ply damage was localised at impact location in dynamically tested specimens, whereas in the quasi-static specimens, it spread almost over the entire interface.

51. 500,000 POUND STATIC TEST FACILITY: CLOSEUP VIEW FROM EAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

51. 500,000 POUND STATIC TEST FACILITY: CLOSE-UP VIEW FROM EAST SHOWING MOVABLE OBSERVATION MIRRORS WITH TRACKS - White Sands Missile Range, V-2 Rocket Facilities, Near Headquarters Area, White Sands, Dona Ana County, NM

Pile Driving Analysis for Pile Design and Quality Assurance

DOT National Transportation Integrated Search

2017-08-01

Driven piles are commonly used in foundation engineering. The most accurate measurement of pile capacity is achieved from measurements made during static load tests. Static load tests, however, may be too expensive for certain projects. In these case...

Radar cross section models for limited aspect angle windows

NASA Astrophysics Data System (ADS)

Robinson, Mark C.

1992-12-01

This thesis presents a method for building Radar Cross Section (RCS) models of aircraft based on static data taken from limited aspect angle windows. These models statistically characterize static RCS. This is done to show that a limited number of samples can be used to effectively characterize static aircraft RCS. The optimum models are determined by performing both a Kolmogorov and a Chi-Square goodness-of-fit test comparing the static RCS data with a variety of probability density functions (pdf) that are known to be effective at approximating the static RCS of aircraft. The optimum parameter estimator is also determined by the goodness of-fit tests if there is a difference in pdf parameters obtained by the Maximum Likelihood Estimator (MLE) and the Method of Moments (MoM) estimators.

How a GNSS Receiver Is Held May Affect Static Horizontal Position Accuracy

PubMed Central

Weaver, Steven A.; Ucar, Zennure; Bettinger, Pete; Merry, Krista

2015-01-01

The static horizontal position accuracy of a mapping-grade GNSS receiver was tested in two forest types over two seasons, and subsequently was tested in one forest type against open sky conditions in the winter season. The main objective was to determine whether the holding position during data collection would result in significantly different static horizontal position accuracy. Additionally, we wanted to determine whether the time of year (season), forest type, or environmental variables had an influence on accuracy. In general, the F4Devices Flint GNSS receiver was found to have mean static horizontal position accuracy levels within the ranges typically expected for this general type of receiver (3 to 5 m) when differential correction was not employed. When used under forest cover, in some cases the GNSS receiver provided a higher level of static horizontal position accuracy when held vertically, as opposed to held at an angle or horizontally (the more natural positions), perhaps due to the orientation of the antenna within the receiver, or in part due to multipath or the inability to use certain satellite signals. Therefore, due to the fact that numerous variables may affect static horizontal position accuracy, we only conclude that there is weak to moderate evidence that the results of holding position are significant. Statistical test results also suggest that the season of data collection had no significant effect on static horizontal position accuracy, and results suggest that atmospheric variables had weak correlation with horizontal position accuracy. Forest type was found to have a significant effect on static horizontal position accuracy in one aspect of one test, yet otherwise there was little evidence that forest type affected horizontal position accuracy. Since the holding position was found in some cases to be significant with regard to the static horizontal position accuracy of positions collected in forests, it may be beneficial to have an understanding of antenna positioning within the receiver to achieve the greatest accuracy during data collection. PMID:25923667

How a GNSS Receiver Is Held May Affect Static Horizontal Position Accuracy.

PubMed

Weaver, Steven A; Ucar, Zennure; Bettinger, Pete; Merry, Krista

2015-01-01

The static horizontal position accuracy of a mapping-grade GNSS receiver was tested in two forest types over two seasons, and subsequently was tested in one forest type against open sky conditions in the winter season. The main objective was to determine whether the holding position during data collection would result in significantly different static horizontal position accuracy. Additionally, we wanted to determine whether the time of year (season), forest type, or environmental variables had an influence on accuracy. In general, the F4Devices Flint GNSS receiver was found to have mean static horizontal position accuracy levels within the ranges typically expected for this general type of receiver (3 to 5 m) when differential correction was not employed. When used under forest cover, in some cases the GNSS receiver provided a higher level of static horizontal position accuracy when held vertically, as opposed to held at an angle or horizontally (the more natural positions), perhaps due to the orientation of the antenna within the receiver, or in part due to multipath or the inability to use certain satellite signals. Therefore, due to the fact that numerous variables may affect static horizontal position accuracy, we only conclude that there is weak to moderate evidence that the results of holding position are significant. Statistical test results also suggest that the season of data collection had no significant effect on static horizontal position accuracy, and results suggest that atmospheric variables had weak correlation with horizontal position accuracy. Forest type was found to have a significant effect on static horizontal position accuracy in one aspect of one test, yet otherwise there was little evidence that forest type affected horizontal position accuracy. Since the holding position was found in some cases to be significant with regard to the static horizontal position accuracy of positions collected in forests, it may be beneficial to have an understanding of antenna positioning within the receiver to achieve the greatest accuracy during data collection.

Does the Value of Dynamic Assessment in Predicting End-of-First-Grade Mathematics Performance Differ as a Function of English Language Proficiency?

PubMed Central

Seethaler, Pamela M.; Fuchs, Lynn S.; Fuchs, Douglas; Compton, Donald L.

2015-01-01

The purpose of this study was to assess the added value of dynamic assessment (DA) beyond more conventional static measures for predicting individual differences in year-end 1st-grade calculation (CA) and word-problem (WP) performance, as a function of limited English proficiency (LEP) status. At the start of 1st grade, students (129 LEP; 163 non-LEP) were assessed on a brief static mathematics test, an extended static mathematics test, static tests of domain-general abilities associated with CAs and WPs (vocabulary; reasoning), and DA. Near end of 1st grade, they were assessed on CA and WP. Regression analyses indicated that the value of the predictor depends on the predicted outcome and LEP status. In predicting CAs, the extended mathematics test and DA uniquely explained variance for LEP children, with stronger predictive value for the extended mathematics test; for non-LEP children, the extended mathematics test was the only significant predictor. However, in predicting WPs, only DA and vocabulary were uniquely predictive for LEP children, with stronger value for DA; for non-LEP children, the extended mathematics test and DA were comparably uniquely predictive. Neither the brief static mathematics test nor reasoning was significant in predicting either outcome. The potential value of a gated screening process, using an extended mathematics assessment to predict CAs and using DA to predict WPs, is discussed. PMID:26523068

Elevated-Temperature Tests Under Static and Aerodynamic Conditions on Honeycomb-Core Sandwich Panels

NASA Technical Reports Server (NTRS)

Groen, Joseph M.; Johnson, Aldie E., Jr.

1959-01-01

Stainless-steel honeycomb-core sandwich panels which differed primarily in skin thicknesses were tested at elevated temperatures under static and aerodynamic conditions. The results of these tests were evaluated to determine the insulating effectiveness and structural integrity of the panels. The static radiant-heating tests were performed in front of a quartz-tube radiant heater at panel skin temperatures up to 1,5000 F. The aerodynamic tests were made in a Mach 1.4 heated blowdown wind tunnel. The tunnel temperature was augmented by additional heat supplied by a radiant heater which raised the panel surface temperature above 8000 F during air flow. Static radiant-heating tests of 2 minutes duration showed that all the panels protected the load-carrying structure about equally well. Thin-skin panels showed an advantage for this short-time test over thick-skin panels from a standpoint of weight against insulation. Permanent inelastic strains in the form of local buckles over each cell of the honeycomb core caused an increase in surface roughness. During the aero- dynamic tests all of the panels survived with little or no damage, and panel flutter did not occur.

Flowfield measurements in the NASA Lewis Research Center 9- by 15-foot low-speed wind tunnel

NASA Technical Reports Server (NTRS)

Hughes, Christopher E.

1989-01-01

An experimental investigation was conducted in the NASA Lewis 9- by 15-Foot Low-Speed Wind Tunnel to determine the flow characteristics in the test section during wind tunnel operation. In the investigation, a 20-probe horizontally-mounted Pitot-static flow survey rake was used to obtain cross-sectional total and static pressure surveys at four axial locations in the test section. At each axial location, the cross-sectional flowfield surveys were made by repositioning the Pitot-static flow survey rake vertically. In addition, a calibration of the new wind tunnel rake instrumentation, used to determine the wind tunnel operating conditions, was performed. Boundary laser surveys were made at three axial locations in the test section. The investigation was conducted at tunnel Mach numbers 0.20, 0.15, 0.10, and 0.05. The test section profile results from the investigation indicate that fairly uniform total pressure profiles (outside the test section boundary layer) and fairly uniform static pressure and Mach number profiles (away from the test section walls and downstream of the test section entrance) exist throughout in the wind tunnel test section.

Wind Tunnel to Atmospheric Mapping for Static Aeroelastic Scaling

NASA Technical Reports Server (NTRS)

Heeg, Jennifer; Spain, Charles V.; Rivera, J. A.

2004-01-01

Wind tunnel to Atmospheric Mapping (WAM) is a methodology for scaling and testing a static aeroelastic wind tunnel model. The WAM procedure employs scaling laws to define a wind tunnel model and wind tunnel test points such that the static aeroelastic flight test data and wind tunnel data will be correlated throughout the test envelopes. This methodology extends the notion that a single test condition - combination of Mach number and dynamic pressure - can be matched by wind tunnel data. The primary requirements for affecting this extension are matching flight Mach numbers, maintaining a constant dynamic pressure scale factor and setting the dynamic pressure scale factor in accordance with the stiffness scale factor. The scaling is enabled by capabilities of the NASA Langley Transonic Dynamics Tunnel (TDT) and by relaxation of scaling requirements present in the dynamic problem that are not critical to the static aeroelastic problem. The methodology is exercised in two example scaling problems: an arbitrarily scaled wing and a practical application to the scaling of the Active Aeroelastic Wing flight vehicle for testing in the TDT.

Prevention and treatment of Nitrite toxicity in juvenile steelhead trout (Salmo gairdneri)

USGS Publications Warehouse

Wedemeyer, Gary A.; Yasutake, W.T.

1978-01-01

The efficacy of mineral salts, pH, and tetramethylthianine (methylene blue) treatment in reducing the acute toxicity of nitrite to fingerling steelhead trout (Salmo gairdneri) was determined using a static bioassay system at 10 °C. The acute toxicity (96-h LC50) was reduced by a factor of about 24 for 5-g steelhead and 13 for 10-g fish when the total water hardness was increased from 25 to 300 mg/L (as CaCO3). NaCl or CaCl2 additions (0–200 mg/L) reduced toxicity by a factor of up to 3 for NaCl and 50 for CaCl2. Increasing the pH from 6.0 to 8.0 decreased toxicity by a factor of about 8 for the smaller and 3 for the larger fish. Methylene blue at 0.1 or 1.0 mg/L was effective in decreasing acute toxicity. For alleviating methemoglobinemia, removing the fish to freshwater for 48 h was about as effective as 1.0 mg/L methylene blue. Chronic exposure in soft water to 0.03 mg/L NO2-N for 6 mo caused no significant growth reduction, gill histological changes, hematological dyscrasias, or impaired ability of the smolts to adapt to 30‰ seawater and grow for an additional 2 mo. Key words: nitrite, toxicity, fish, methylene blue, pH, salts, acute toxicity, chronic toxicity

Static Force-Deflection Properties of Automobile Steering Components

DOT National Transportation Integrated Search

1987-06-01

This report provides the static force-deflection test results for 28 steering columns and 24 steering wheels used in domestic and import passener cars from model year 1975 to 1985. The steering columns and wheels tested include approzimately 90 perce...

Saturn Apollo Program

NASA Image and Video Library

1964-12-01

At the Marshall Space Flight Center (MSFC), the fuel tank assembly for the Saturn V S-IC-T (static test stage) fuel tank assembly is mated to the liquid oxygen (LOX) tank in building 4705. This stage underwent numerous static firings at the newly-built S-IC Static Test Stand at the MSFC west test area. The S-IC (first) stage used five F-1 engines that produced a total thrust of 7,500,000 pounds as each engine produced 1,500,000 pounds of thrust. The S-IC stage lifted the Saturn V vehicle and Apollo spacecraft from the launch pad.

Effects of static tensile load on the thermal expansion of Gr/PI composite material

NASA Technical Reports Server (NTRS)

Farley, G. L.

1981-01-01

The effect of static tensile load on the thermal expansion of Gr/PI composite material was measured for seven different laminate configurations. A computer program was developed which implements laminate theory in a piecewise linear fashion to predict the coupled nonlinear thermomechanical behavior. Static tensile load significantly affected the thermal expansion characteristics of the laminates tested. This effect is attributed to a fiber instability micromechanical behavior of the constituent materials. Analytical results correlated reasonably well with free thermal expansion tests (no load applied to the specimen). However, correlation was poor for tests with an applied load.

Space Shuttle SRM development. [Solid Rocket Motors

NASA Technical Reports Server (NTRS)

Brinton, B. C.; Kilminster, J. C.

1979-01-01

The successful static test of the fourth Development Space Shuttle Solid Rocket Motor (SRM) in February 1979 concluded the development testing phase of the SRM Project. Qualification and flight motors are currently being fabricated, with the first qualification motor to be static tested. Delivered thrust-time traces on all development motors were very close to predicted values, and both specific and total impulse exceeded specification requirements. 'All-up' static tests conducted with a solid rocket booster equipment on development motors achieved all test objectives. Transportation and support equipment concepts have been proven, baselining is complete, and component reusability has been demonstrated. Evolution of the SRM transportation support equipment, and special test equipment designs are reviewed, and development activities discussed. Handling and processing aspects of large, heavy components are described.

Eccentric Training and Static Stretching Improve Hamstring Flexibility of High School Males

PubMed Central

Bandy, William D.

2004-01-01

Objective: To determine if the flexibility of high-school-aged males would improve after a 6-week eccentric exercise program. In addition, the changes in hamstring flexibility that occurred after the eccentric program were compared with a 6-week program of static stretching and with a control group (no stretching). Design and Setting: We used a test-retest control group design in a laboratory setting. Subjects were assigned randomly to 1 of 3 groups: eccentric training, static stretching, or control. Subjects: A total of 69 subjects, with a mean age of 16.45 ± 0.96 years and with limited hamstring flexibility (defined as 20° loss of knee extension measured with the thigh held at 90° of hip flexion) were recruited for this study. Measurements: Hamstring flexibility was measured using the passive 90/90 test before and after the 6-week program. Results: Differences were significant for test and for the test-by-group interaction. Follow-up analysis indicated significant differences between the control group (gain = 1.67°) and both the eccentric-training (gain = 12.79°) and static-stretching (gain = 12.05°) groups. No difference was found between the eccentric and static-stretching groups. Conclusions: The gains achieved in range of motion of knee extension (indicating improvement in hamstring flexibility) with eccentric training were equal to those made by statically stretching the hamstring muscles. PMID:15496995

Eccentric Training and Static Stretching Improve Hamstring Flexibility of High School Males.

PubMed

Nelson, Russell T; Bandy, William D

2004-09-01

OBJECTIVE: To determine if the flexibility of high-school-aged males would improve after a 6-week eccentric exercise program. In addition, the changes in hamstring flexibility that occurred after the eccentric program were compared with a 6-week program of static stretching and with a control group (no stretching). DESIGN AND SETTING: We used a test-retest control group design in a laboratory setting. Subjects were assigned randomly to 1 of 3 groups: eccentric training, static stretching, or control. SUBJECTS: A total of 69 subjects, with a mean age of 16.45 +/- 0.96 years and with limited hamstring flexibility (defined as 20 degrees loss of knee extension measured with the thigh held at 90 degrees of hip flexion) were recruited for this study. MEASUREMENTS: Hamstring flexibility was measured using the passive 90/90 test before and after the 6-week program. RESULTS: Differences were significant for test and for the test-by-group interaction. Follow-up analysis indicated significant differences between the control group (gain = 1.67 degrees ) and both the eccentric-training (gain = 12.79 degrees ) and static-stretching (gain = 12.05 degrees ) groups. No difference was found between the eccentric and static-stretching groups. CONCLUSIONS: The gains achieved in range of motion of knee extension (indicating improvement in hamstring flexibility) with eccentric training were equal to those made by statically stretching the hamstring muscles.

Hemodynamic changes after static and dynamic exercises and treadmill stress test; different patterns in patients with primary benign exertional headache?

PubMed

Kordi, Ramin; Mazaheri, Reza; Rostami, Mohsen; Mansournia, Mohammad Ali

2012-01-01

The pathophysiology of primary benign exertional headache (EH) is not still clearly defined. Some researchers have suggested an impaired vascular response as the etiology of this disorder. In this study we investigated whether there are any differences in blood pressure (BP) and heart rate (HR) of the subjects in course of the static and dynamic exercises and the treadmill stress test between those with and without EH. From university students, 22 patients with EH (mean age: 19.8 ± 2.10, Female to Male: 7:15) and 20 normal subjects (mean age: 19.3 ± 1.97, Female: Male: 8:12) were recruited. All the subjects performed the static and dynamic exercises at 30 and 20 percent of the maximal voluntary contraction (MVC) and Bruce treadmill stress test according to the standard protocols. HR and BP of all the cases at the baseline and during and immediately after each test were measured. No significant difference was found between the mean rise of HR, systolic and diastolic BP of the subjects with and without EH in static and dynamic exercises and also treadmill stress test. It seems that between those with and without EH, there is no significant difference in rise of HR and BP response to static and dynamic exercises and treadmill stress test. Further studies are required to find the pathophysiology and risk factors of EH.

FEM Modeling of the Relationship between the High-Temperature Hardness and High-Temperature, Quasi-Static Compression Experiment.

PubMed

Zhang, Tao; Jiang, Feng; Yan, Lan; Xu, Xipeng

2017-12-26

The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM) model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE) simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature.

FEM Modeling of the Relationship between the High-Temperature Hardness and High-Temperature, Quasi-Static Compression Experiment

PubMed Central

Zhang, Tao; Jiang, Feng; Yan, Lan; Xu, Xipeng

2017-01-01

The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM) model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE) simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature. PMID:29278398

Insights into the selective binding and toxic mechanism of microcystin to catalase

NASA Astrophysics Data System (ADS)

Hu, Yuandong; Da, Liangjun

2014-03-01

Microcystin is a sort of cyclic nonribosomal peptides produced by cyanobacteria. It is cyanotoxin, which can be very toxic for plants and animals including humans. The present study evaluated the interaction of microcystin and catalase, under physiological conditions by means of fluorescence, three-dimensional (3D) fluorescence, circular dichroism (CD), Fourier Transform infrared (FT-IR) spectroscopy, and enzymatic reactionkinetic techniques. The fluorescence data showed that microcystin could bind to catalase to form a complex. The binding process was a spontaneous molecular interaction procedure, in which electrostatic interactions played a major role. Energy transfer and fluorescence studies proved the existence of a static binding process. Additionally, as shown by the three-dimensional fluorescence, CD and FT-IR results, microcystin could lead to conformational and microenvironmental changes of the protein, which may affect the physiological functions of catalase. The work provides important insights into the toxicity mechanism of microcystin in vivo.

[Research progress on mechanical performance evaluation of artificial intervertebral disc].

PubMed

Li, Rui; Wang, Song; Liao, Zhenhua; Liu, Weiqiang

2018-03-01

The mechanical properties of artificial intervertebral disc (AID) are related to long-term reliability of prosthesis. There are three testing methods involved in the mechanical performance evaluation of AID based on different tools: the testing method using mechanical simulator, in vitro specimen testing method and finite element analysis method. In this study, the testing standard, testing equipment and materials of AID were firstly introduced. Then, the present status of AID static mechanical properties test (static axial compression, static axial compression-shear), dynamic mechanical properties test (dynamic axial compression, dynamic axial compression-shear), creep and stress relaxation test, device pushout test, core pushout test, subsidence test, etc. were focused on. The experimental techniques using in vitro specimen testing method and testing results of available artificial discs were summarized. The experimental methods and research status of finite element analysis were also summarized. Finally, the research trends of AID mechanical performance evaluation were forecasted. The simulator, load, dynamic cycle, motion mode, specimen and test standard would be important research fields in the future.

The Use of Interactive Computer Animations Based on POE as a Presentation Tool in Primary Science Teaching

NASA Astrophysics Data System (ADS)

Akpınar, Ercan

2014-08-01

This study investigates the effects of using interactive computer animations based on predict-observe-explain (POE) as a presentation tool on primary school students' understanding of the static electricity concepts. A quasi-experimental pre-test/post-test control group design was utilized in this study. The experiment group consisted of 30 students, and the control group of 27 students. The control group received normal instruction in which the teacher provided instruction by means of lecture, discussion and homework. Whereas in the experiment group, dynamic and interactive animations based on POE were used as a presentation tool. Data collection tools used in the study were static electricity concept test and open-ended questions. The static electricity concept test was used as pre-test before the implementation, as post-test at the end of the implementation and as delay test approximately 6 weeks after the implementation. Open-ended questions were used at the end of the implementation and approximately 6 weeks after the implementation. Results indicated that the interactive animations used as presentation tools were more effective on the students' understanding of static electricity concepts compared to normal instruction.

Characterization of Triaxial Braided Composite Material Properties for Impact Simulation

NASA Technical Reports Server (NTRS)

Roberts, Gary D.; Goldberg, Robert K.; Biniendak, Wieslaw K.; Arnold, William A.; Littell, Justin D.; Kohlman, Lee W.

2009-01-01

The reliability of impact simulations for aircraft components made with triaxial braided carbon fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Improvements to standard quasi-static test methods are needed to account for the large unit cell size and localized damage within the unit cell. The deformation and damage of a triaxial braided composite material was examined using standard quasi-static in-plane tension, compression, and shear tests. Some modifications to standard test specimen geometries are suggested, and methods for measuring the local strain at the onset of failure within the braid unit cell are presented. Deformation and damage at higher strain rates is examined using ballistic impact tests on 61- by 61- by 3.2-mm (24- by 24- by 0.125-in.) composite panels. Digital image correlation techniques were used to examine full-field deformation and damage during both quasi-static and impact tests. An impact analysis method is presented that utilizes both local and global deformation and failure information from the quasi-static tests as input for impact simulations. Improvements that are needed in test and analysis methods for better predictive capability are examined.

Performance characteristics of axisymmetric convergent-divergent exhaust nozzles with longitudinal slots in the divergent

NASA Technical Reports Server (NTRS)

Leavitt, L. D.; Bangert, L. S.

1982-01-01

An investigation was conducted in the Langley 16 foot Transonic Tunnel and in the static test facility of that tunnel to determine the effects of divergent flap ventilation of an axisymmetric nozzle on nozzle internal (static) and wind on performance. Tests were conducted at 0 deg angle of attack at static conditions and at Mach numbers from 0.6 to 1.2. Ratios of jet total pressure to free stream static pressure were varied from 1.0 (jet off) to approximately 14.0 depending on Mach number. The results of this study indicate that divergent flap ventilation generally provided large performance benefits at overexpanded nozzle conditions and performance reductions at underexpanded nozzle conditions when compared to the baseline (unventilated) nozzles. Ventilation also reduced the peak static and wind on performance levels.

Measuring Cognitive Load in Test Items: Static Graphics versus Animated Graphics

ERIC Educational Resources Information Center

Dindar, M.; Kabakçi Yurdakul, I.; Inan Dönmez, F.

2015-01-01

The majority of multimedia learning studies focus on the use of graphics in learning process but very few of them examine the role of graphics in testing students' knowledge. This study investigates the use of static graphics versus animated graphics in a computer-based English achievement test from a cognitive load theory perspective. Three…

Fluid mechanics of dynamic stall. II - Prediction of full scale characteristics

NASA Technical Reports Server (NTRS)

Ericsson, L. E.; Reding, J. P.

1988-01-01

Analytical extrapolations are made from experimental subscale dynamics to predict full scale characteristics of dynamic stall. The method proceeds by establishing analytic relationships between dynamic and static aerodynamic characteristics induced by viscous flow effects. The method is then validated by predicting dynamic test results on the basis of corresponding static test data obtained at the same subscale flow conditions, and the effect of Reynolds number on the static aerodynamic characteristics are determined from subscale to full scale flow conditions.

Static electricity: A literature review

NASA Astrophysics Data System (ADS)

Crow, Rita M.

1991-11-01

The major concern with static electricity is its discharging in a flammable atmosphere which can explode and cause a fire. Textile materials can have their electrical resistivity decreased by the addition of antistatic finishes, imbedding conductive particles into the fibres or by adding metal fibers to the yarns. The test methods used in the studies of static electricity include measuring the static properties of materials, of clothed persons, and of the ignition energy of flammable gases. Surveys have shown that there is sparse evidence for fires definitively being caused by static electricity. However, the 'worst-case' philosophy has been adopted and a static electricity safety code is described, including correct grounding procedures and the wearing of anti-static clothing and footwear.

Methods For Collecting , Culturing And Performing Toxicity Tests With Daphnia ambigua

DOE Office of Scientific and Technical Information (OSTI.GOV)

Specht, Winona L.

2005-07-01

Toxicity tests conducted on water collected from impacted locations in SRS streams often failed chronic toxicity tests and sometimes failed acute toxicity tests (Specht 1995). These findings prompted SRS to determine the cause of the failures. Some SRS NPDES outfalls were also failing chronic toxicity tests, even though no toxicant could be identified and when TIEs were performed, none of the TIE treatments removed the toxicity. Ultimately, it was determined that the failures were due to the low hardness of SRS surface waters, rather than to the presence of a toxicant. The species of cladoceran that the EPA recommends formore » toxicity testing, Ceriodaphnia dubia, is stressed by the very low hardness of SRS waters. SRS developed an alternate species toxicity test that is similar to the EPA test, but uses an indigenous cladoceran, Daphnia ambigua (Specht and Harmon, 1997; Harmon et al., 2003). In 2001, SCDHEC approved the use of D. ambigua for toxicity testing at SRS, contingent upon approval by EPA Region 4. In 2002, EPA Region 4 approved the use of this species for compliance toxicity testing at SRS. Ultimately, the use of this species demonstrated that SRS effluents were not toxic, and most toxicity testing requirements were removed from the NPDES permit that was issued in December 2003, with the exception of one round of chronic definitive testing on outfalls A-01, A-11, and G-10 just before the next NPDES permit application is submitted to SCDHEC. Although the alternate species test was developed at SRS (1996-1998), the culture was transferred to a contract toxicity testing lab (ETT Environmental) located in Greer, SC in 1998. ETT Environmental became certified by SCDHEC to perform toxicity tests using D. ambigua in 2002, and at this time is the only laboratory certified by SCDHEC to perform tests with this species. Because of the expense associated with maintaining the D. ambigua culture for several years when no toxicity testing is required, SRS decided to suspend financial support associated with maintaining the cultures until testing is needed. The purpose of this document is to provide guidance on how to establish a laboratory culture of D. ambigua so that a culture can be restarted when needed.« less

Static pile load tests on driven piles into Intermediate-Geo Materials.

DOT National Transportation Integrated Search

2016-09-01

The Wisconsin Department of Transportation (WisDOT) has concerns with both predicting pile lengths and pile capacities for H-piles driven into Intermediate-Geo Materials (IGM). The goal of the research was to perform 7 static axial load tests at 7 lo...

Prevention of zebra mussel infestation and dispersal during aquaculture operations

USGS Publications Warehouse

Waller, D.L.; Fisher, S.W.; Dabrowska, H.

1996-01-01

The zebra mussel Dreissena polymorpha, an exotic invasive species, poses a major threat to North American fish management programs and the aquaculture industry. Fish hatcheries may become infected with zebra mussels from a variety of sources, including the water supply, fish shipments, boats, and equipment. The hatcheries could then serve as agents for the overland dispersal of zebra mussels into stocked waters and to other fish hatcheries. We evaluated the effectiveness and safety of aquaculture chemicals for use in controlling zebra mussels in fish hatcheries and preventing dispersal of veligers during fish transport. Chemicals were evaluated for use in fish transport and as disinfectants for ponds and equipment. Standardized static toxicity tests were conducted with representative species of warmwater, coolwater, and coldwater fishes and with larval (3-d-old veligers), early juvenile (settling larvae), and adult zebra mussels. Chemical concentrations and exposure durations were based on recommended treatment levels for fish, eggs, and ponds. Recommended treatment levels were also exceeded, if necessary, to establish lethal levels for zebra mussels of different developmental stages. Our results indicate that some chemicals currently in use in hatcheries may be effective for controlling zebra mussels in various operations. Chloride salts were the safest and most effective therapeutants tested for use in fish transport. The toxicity of chloride salts to fish varied among species and with temperature; only one treatment regime (sodium chloride at 10,000 mg/L) was safe to all fish species that we tested, but it was only effective on veliger and settler stages of the zebra mussel. Effective disinfectants were benzalkonium chloride for use on equipment and rotenone for use in ponds after fish are harvested. The regulatory status of the identified chemicals is discussed as well as several nonchemical control alternatives.

Transient Pressure Test Article (TPTA) 1.1 and 1.1A, volume 1

NASA Technical Reports Server (NTRS)

Rebells, Clarence A.

1988-01-01

This final test report presents the results obtained during the static hot firing and cold-gas high Q tests of the first Transient Pressure Test Article (TPTA) 1.1. The TPTA consisted of field test joints A and B, which were the original RSRM J-insulation configuration, with a metal capture feature. It also consisted of a flight configuration nozzle-to-case test joint (Joint D) with shorter vent slots. Fluorocarbon O-rings were used in all the test joints. The purpose of the TPTA tests is to evaluate and characterize the RSMR field and nozzle-to-case joints under the influence of ignition and strut loads during liftoff anf high Q. All objectives of the cold-gas high Q (TPTA 1.1A) test were met and all measurements were close to predicted values. During the static hot-firing test (TPTA 1.1), the motor was inadvertently plugged by the quench injector plug, making it a more severe test, although no strut loads were applied. The motor was depressurized after approximately 11 min using an auxiliary system, and no anomalies were noted. In the static hot-firing test, pressure was incident on the insulation and the test joint gaps were within the predicted range. During the static hot-firing test, no strut loads were applied because the loading system malfunctioned. For this test, all measurements were within range of similar tests performed without strut loads.

Assessment of current AASHTO LRFD methods for static pile capacity analysis in Rhode Island soils.

DOT National Transportation Integrated Search

2013-07-01

This report presents an assessment of current AASHTO LRFD methods for static pile capacity analysis in Rhode : Island soils. Current static capacity methods and associated resistance factors are based on pile load test data in sands : and clays. Some...

Impact evaluation of composite floor sections

NASA Technical Reports Server (NTRS)

Boitnott, Richard L.; Fasanella, Edwin L.

1989-01-01

Graphite-epoxy floor sections representative of aircraft fuselage construction were statically and dynamically tested to evaluate their response to crash loadings. These floor sections were fabricated using a frame-stringer design typical of present aluminum aircraft without features to enhance crashworthiness. The floor sections were tested as part of a systematic research program developed to study the impact response of composite components of increasing complexity. The ultimate goal of the research program is to develop crashworthy design features for future composite aircraft. Initially, individual frames of six-foot diameter were tested both statically and dynamically. The frames were then used to construct built-up floor sections for dynamic tests at impact velocities of approximately 20 feet/sec to simulate survivable crash velocities. In addition, static tests were conducted to gain a better understanding of the failure mechanisms seen in the dynamic tests.

Laboratory and field performance of FOS sensors in static and dynamic strain monitoring in concrete bridge decks

NASA Astrophysics Data System (ADS)

Benmokrane, B.; Debaiky, A.; El-Ragaby, A.; Roy, R.; El-Gamal, S.; El-Salakawy, E.

2006-03-01

There is a growing need for designing and constructing innovative concrete bridges using FRP reinforcing bars as internal reinforcement to avoid the corrosion problems and high costs of maintenance and repair. For efficient use and to increase the lifetime of these bridges, it is important to develop efficient monitoring systems for such innovative structures. Fabry-Perot and Bragg fibre optic sensors (FOS) that can measure the strains and temperature are promising candidates for life-long health monitoring of these structures. This article reports laboratory and field performance of Fabry-Perot and Bragg FOS sensors as well as electrical strain gauges in static and dynamic strain monitoring in concrete bridge decks. The laboratory tests include tensile testing of glass FRP bars and testing of full-scale concrete bridge deck slabs reinforced with glass and carbon FRP bars under static and cyclic concentrated loads. The field tests include static and dynamic testing of two bridges reinforced with steel and glass FRP bars. The obtained strain results showed satisfactory agreement between the different gauges.

Is the fish embryo toxicity test (FET) with the zebrafish (Danio rerio) a potential alternative for the fish acute toxicity test?

PubMed

Lammer, E; Carr, G J; Wendler, K; Rawlings, J M; Belanger, S E; Braunbeck, Th

2009-03-01

The fish acute toxicity test is a mandatory component in the base set of data requirements for ecotoxicity testing. The fish acute toxicity test is not compatible with most current animal welfare legislation because mortality is the primary endpoint and it is often hypothesized that fish suffer distress and perhaps pain. Animal alternative considerations have also been incorporated into new European REACH regulations through strong advocacy for the reduction of testing with live animals. One of the most promising alternative approaches to classical acute fish toxicity testing with live fish is the fish embryo toxicity (FET) test. The FET has been a mandatory component in routine whole effluent testing in Germany since 2005 and has already been standardized at the international level. In order to analyze the applicability of the FET also in chemical testing, a comparative re-evaluation of both fish and fish embryo toxicity data was carried out for a total of 143 substances, and statistical approaches were developed to evaluate the correlation between fish and fish embryo toxicity data. Results confirm that fish embryo tests are neither better nor worse than acute fish toxicity tests and provide strong scientific support for the FET as a surrogate for the acute fish toxicity test.

A Study on the D. magna and V. fischeri Toxicity Relationship of Industrial Wastewater from Korea

NASA Astrophysics Data System (ADS)

Pyo, S.; Lee, S.; Chun Sang, H.; Park, T. J.; Kim, M. S.

2015-12-01

It is well known that high concentration of TDS (total dissolved solid) in industrial effluent gives rise to the toxicity to the Daphnia magna toxicity test. D. magna is vulnerable to relatively low TDS concentration showing the 24-hr EC50 of Salinity 0.6% (as the sea salt concentration). Recently, standard mandatory toxicity testing using Daphnia magna has been used to monitor industrial effluent toxicity according to Korea standard method (Acute Toxicity Test Method of the Daphnia magna Straus (Cladocera, Crustacea), ES 04704. 1a) under regulation. Since only one acute toxicity testing is applied in the present, we are trying to introduce microbial battery for more complete toxicity assessment. In this study, the acute toxicities between daphnids and microbes were compared. The results of D. magna and Vibrio fischeri toxicity test from 165 industrial wastewater effluents showed high positive correlation. In addition, the possibility of predicting daphnia toxicity from the bacterial toxicity data amounts to 92.6% if we consider salinity effect (>5ppt) together. From this study, we found that the V. fischeri toxicity test is a powerful battery tool to assess the industrial wastewater toxicity. Here, we suggest that luminescent bacteria toxicity test be useful not only for complete toxicity assessment which can't be obtained by daphnia toxicity testing only but also for the reduction cost, time, and labor in the Korean society. Keywords : D. magna, V. fischeri, Industrial waste water, battery test Acknowledgement This research was supported by a grant (15IFIP-B089908-02) from Plant Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government

Saturn Apollo Program

NASA Image and Video Library

1967-08-01

This photograph is a view of the Saturn V S-IC-5 (first) flight stage static test firing at the S-IC-B1 test stand at the Mississippi Test Facility (MTF), Bay St. Louis, Mississippi. Begirning operations in 1966, the MTF has two test stands, a dual-position structure for running the S-IC stage at full throttle, and two separate stands for the S-II (Saturn V third) stage. It became the focus of the static test firing program. The completed S-IC stage was shipped from Michoud Assembly Facility (MAF) to the MTF. The stage was then installed into the 407-foot-high test stand for the static firing tests before shipment to the Kennedy Space Center for final assembly of the Saturn V vehicle. The MTF was renamed to the National Space Technology Laboratory (NSTL) in 1974 and later to the Stennis Space Center (SSC) in May 1988.

Constructing and Implementing a Four Tier Test about Static Electricity to Diagnose Pre-service Elementary School Teacher’ Misconceptions

NASA Astrophysics Data System (ADS)

Hermita, N.; Suhandi, A.; Syaodih, E.; Samsudin, A.; Isjoni; Johan, H.; Rosa, F.; Setyaningsih, R.; Sapriadil; Safitri, D.

2017-09-01

We have already constructed and implemented the diagnostic test formed in the four tier test to diagnose pre-service elementary teachers’ misconceptions about static electricity. The method which is utilized in this study is 3D-1I (Define, Design, Develop and Implementation) conducted to the pre-service elementary school teachers. The number of respondents involved in the study is 78 students of PGSD FKIP Universitas Riau. The data was collected by administering diagnostic test items in the form of four tier test. The result indicates that there are several misconceptions related to static electricity concept, these include: 1) Electrostatic objects cannot attract neutral objects, 2) A neutral object is an object that does not contain an electrical charge, and 3) the magnitude of the tensile force between two charged objects depends on the size of the charge. Moreover, the research’s results establish that the diagnostic test is able to analyse number of misconceptions and classify level of understanding pre-service elementary school teachers that is scientific knowledge, misconception, lack knowledge, and error. In conclusion, the diagnostic test item in the form of four tier test has already been constructed and implemented to diagnose students’ conceptions on static electricity.

Evaluation of several chemical disinfectants for removing zebra mussels from unionid mussels

USGS Publications Warehouse

Waller, D.L.; Fisher, S.W.

1998-01-01

We evaluated the safety and effectiveness of chemical treatments for killing veliger and juvenile stages of the zebra mussel Dreissena polymorpha attached to unionid mussels. Static toxicity tests were conducted on eight unionid mussel species with common aquaculture chemicals (benzalkonium chloride, formalin, hydrogen peroxide, calcium chloride, potassium chloride, and sodium chloride). The concentration and duration of each chemical treatment tested had previously been found to kill zebra mussel veligers and juveniles. Several species (e.g., Elliptio dilatata, Lampsilis cardium, and Lasmigona complanata) incurred less than 10% mortality in chloride salt treatments, while in other species (e.g., Obliquaria reflexa and Leptodea fragilis) mortality varied greatly among treatment regimes. Treatments with benzalkonium chloride, formalin, and hydrogen peroxide were less than 90% effective on juvenile stages of zebra mussels and, therefore, were ruled out after preliminary trials. Limited application of specific chemical treatments may be feasible for more tolerant species; however, effective disinfection of unionid shells will require the use of chemical treatment followed by a quarantine period to completely remove zebra mussel larvae and juveniles.

Applicability of ambient toxicity testing to national or regional water-quality assessment

USGS Publications Warehouse

Elder, John F.

1990-01-01

Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Descriptions of existing conditions may be achieved by various kinds of chemical and hydrologic analyses, whereas information about the effects of such conditions on living organisms depends on biological monitoring. Toxicity testing is one type of biological monitoring that can be used to identify possible effects of toxic contaminants. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water-quality assessments. These purposes may include identification of areas that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. Toxicity-test results are most effective when used as a complement to chemical analyses, hydrologic measurements, and other biological monitoring. However, all toxicity-testing procedures have certain limitations that must be considered in developing the methodology and applications of toxicity testing in any large-scale water-quality-assessment program. A wide variety of toxicity-test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the selections made relative to four characteristics: (1) test species, (2) endpoint (acute or chronic), (3) test-enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity-test approaches vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing, whereby the test organism is exposed to naturally occurring substances that contain toxicant mixtures in an organic or inorganic matrix, is more likely to meet these needs than are procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful interpretation of ambient test results depends on the existence of accompanying chemical analysis of the ambient media. The ambient test substance may be water or sediments. Sediment tests have had limited application, but they are useful because most toxicants tend to accumulate in sediments and many test species either inhabit the sediments or are in frequent contact with them. Biochemical testing methods, which have been developing rapidly in recent years, are likely to be among the most useful procedures for large-scale water-quality assessments. They are relatively rapid and simple, and more. importantly, they focus on biochemical changes that are the initial responses of virtually all organisms to environmental stimuli. Most species are sensitive to relatively few toxicants, and their sensitivities vary as conditions change. Therefore, each test method has particular uses and limitations, and no single test has universal applicability. One of the most informative approaches to toxicity testing is to combine biochemical tests with other test methods in a 'battery of tests' that is diversified enough to characterize different types of toxicants and different trophic levels. However, such an approach can be costly, and if not carefully designed, it may not yield enough additional information to warrant the additional cost. The application of toxicity tests to large-scale water-quality assessments is hampered by a number of difficulties. Toxicity tests often are not sensitive enough to enable detection of most contaminant problems in the natural environment. Furthermore, because sensitivities among different species and test conditions can be highly variable, conclusions about the toxicant problems of an ecosystem are strongly dependent on the test procedure used. In addition, the experimental systems used in toxicity tests cannot replicate the complexity or variability of natural conditions, and positive test results cannot identify the source or nature of

Effects of Static Stretching on Squat Performance in Division I Female Athletes

PubMed Central

HEISEY, CLARE F.; KINGSLEY, J. DEREK

2016-01-01

Static stretching was once recognized as a method of preparation for physical activity that would inhibit performance and increase risk of injury. However, a growing body of research suggests that static stretching may not have an inhibitory effect. Regardless, the data have not examined gender differences or the fatigue index (FI) and flexibility effects of static stretching on the back squat over multiple sets. Therefore, the purpose of this study was to examine the relationship between a static-stretch condition (SC) and control condition (CC) on flexibility and the FI of Division I female athletes during 4 sets of the back squat. Eighteen subjects (mean ± SD; age 20 ± 1 yrs; height 164.5 ± 14.6 cm; mass 74.1 ± 26.8 kg; waist circumference 73.2 ± 5.4 cm) participated in 3 testing days over the course of 3 weeks. Each subject’s 1RM back squat was assessed during the first day of testing and verified during the second. On the third testing day, subjects assigned to the SC held 3 lower-body stretches twice for 30 second intervals and those assigned to the CC rested during the corresponding 7 minutes and 50 second time period. The subjects also performed a fatiguing squat protocol consisting of 4 sets of maximum repetitions on the third day of testing. A significant (p=0.04) interaction was noted for flexibility. No significant interaction (p=0.41) was observed between the FI of the CC (41.8 ± 24.1%) or the SC (27.6 ± 45.2%). These results indicate that static stretching does not have a significant effect on multiple sets of the back squat. Therefore, coaches may allow their athletes to engage in static stretching prior to resistance exercise ad libitum. PMID:27766127

An improved EMD method for modal identification and a combined static-dynamic method for damage detection

NASA Astrophysics Data System (ADS)

Yang, Jinping; Li, Peizhen; Yang, Youfa; Xu, Dian

2018-04-01

Empirical mode decomposition (EMD) is a highly adaptable signal processing method. However, the EMD approach has certain drawbacks, including distortions from end effects and mode mixing. In the present study, these two problems are addressed using an end extension method based on the support vector regression machine (SVRM) and a modal decomposition method based on the characteristics of the Hilbert transform. The algorithm includes two steps: using the SVRM, the time series data are extended at both endpoints to reduce the end effects, and then, a modified EMD method using the characteristics of the Hilbert transform is performed on the resulting signal to reduce mode mixing. A new combined static-dynamic method for identifying structural damage is presented. This method combines the static and dynamic information in an equilibrium equation that can be solved using the Moore-Penrose generalized matrix inverse. The combination method uses the differences in displacements of the structure with and without damage and variations in the modal force vector. Tests on a four-story, steel-frame structure were conducted to obtain static and dynamic responses of the structure. The modal parameters are identified using data from the dynamic tests and improved EMD method. The new method is shown to be more accurate and effective than the traditional EMD method. Through tests with a shear-type test frame, the higher performance of the proposed static-dynamic damage detection approach, which can detect both single and multiple damage locations and the degree of the damage, is demonstrated. For structures with multiple damage, the combined approach is more effective than either the static or dynamic method. The proposed EMD method and static-dynamic damage detection method offer improved modal identification and damage detection, respectively, in structures.

Response, analysis, and design of pile groups subjected to static & dynamic lateral loads.

DOT National Transportation Integrated Search

2003-06-01

Static and dynamic lateral load tests were performed on four full-scale pile groups driven at four different spacings. P-multipliers to account for group : interaction effects were back-calculated for each test. P-multipliers were found to be a funct...

Static RAM data recorder for flight tests

NASA Astrophysics Data System (ADS)

Stoner, D. C.; Eklund, T. F. F.

A static random access memory (RAM) data recorder has been developed to recover strain and acceleration data during development tests of high-speed earth penetrating vehicles. Bilevel inputs are also available for continuity measurements. An iteration of this system was modified for use on water entry evaluations.

Static Evaluation of a NAVSTAR GPS (Magnavox Z-Set) Receiver - May-September 1979

DOT National Transportation Integrated Search

1980-05-01

The report documents the results of the static testing of a NAVSTAR Global Positioning System (GPS) single channel sequential receiver (Magnavox Z-Set). These tests were performed at the Coast Guard District 11 office in Long Beach, CA from May to Se...

Technology advancement of the static feed water electrolysis process

NASA Technical Reports Server (NTRS)

Schubert, F. H.; Wynveen, R. A.

1977-01-01

A program to advance the technology of oxygen- and hydrogen-generating subsystems based on water electrolysis was studied. Major emphasis was placed on static feed water electrolysis, a concept characterized by low power consumption and high intrinsic reliability. The static feed based oxygen generation subsystem consists basically of three subassemblies: (1) a combined water electrolysis and product gas dehumidifier module; (2) a product gas pressure controller and; (3) a cyclically filled water feed tank. Development activities were completed at the subsystem as well as at the component level. An extensive test program including single cell, subsystem and integrated system testing was completed with the required test support accessories designed, fabricated, and assembled. Mini-product assurance activities were included throughout all phases of program activities. An extensive number of supporting technology studies were conducted to advance the technology base of the static feed water electrolysis process and to resolve problems.

The Static and Dynamic Rotary Stability Derivatives at Subsonic Speeds of an Airplane Model Having Wing and Tail Surfaces Swept Back 45 degrees

NASA Technical Reports Server (NTRS)

Lopez, Armando E.; Buell, Donald A.; Tinling, Bruce E.

1959-01-01

Wind-tunnel measurements were made of the static and dynamic rotary stability derivatives of an airplane model having sweptback wing and tail surfaces. The Mach number range of the tests was from 0.23 to 0.94. The components of the model were tested in various combinations so that the separate contribution to the stability derivatives of the component parts and the interference effects could be determined. Estimates of the dynamic rotary derivatives based on some of the simpler existing procedures which utilize static force data were found to be in reasonable agreement with the experimental results at low angles of attack. The results of the static and dynamic measurements were used to compute the short-period oscillatory characteristics of an airplane geometrically similar to the test model. The results of these calculations are compared with military flying qualities requirements.

Static and yawed-rolling mechanical properties of two type 7 aircraft tires

NASA Technical Reports Server (NTRS)

Tanner, J. A.; Stubbs, S. M.; Mccarty, J. L.

1981-01-01

Selected mechanical properties of 18 x 5.5 and 49 x 17 size, type 7 aircraft tires were evaluated. The tires were subjected to pure vertical loads and to combined vertical and lateral loads under both static and rolling conditions. Parameters for the static tests consisted of tire load in the vertical and lateral directions, and parameters for the rolling tests included tire vertical load, yaw angle, and ground speed. Effects of each of these parameters on the measured tire characteristics are discussed and, where possible, compared with previous work. Results indicate that dynamic tire properties under investigation were generally insensitive to speed variations and therefore tend to support the conclusion that many tire dynamic characteristics can be obtained from static and low speed rolling tests. Furthermore, many of the tire mechanical properties are in good agreement with empirical predictions based on earlier research.

Fatigue tests on big structure assemblies of concorde aircraft

NASA Technical Reports Server (NTRS)

Nguyen, V. P.; Perrais, J. P.

1972-01-01

Fatigue tests on structural assemblies of the Concorde supersonic transport aircraft are reported. Two main sections of the aircraft were subjected to pressure, mechanical load, and thermal static tests. The types of fatigue tests conducted and the results obtained are discussed. It was concluded that on a supersonic aircraft whose structural weight is a significant part of the weight analysis, many fatigue and static strength development tests should be made and fatigue and thermal tests of the structures are absolutely necessary.

Application of fish cell lines for evaluating the chromium induced cytotoxicity, genotoxicity and oxidative stress.

PubMed

Taju, G; Abdul Majeed, S; Nambi, K S N; Sahul Hameed, A S

2017-10-01

In the present study, we hypothesize that cytotoxicity, genotoxicity and oxidative stress play a key role in chromium induced toxicity in SISS, SISK, IEE, IEK, IEG, SICH and ICG cell lines after 24 h exposure. Three fish species namely Lates calcarifer, Etroplus suratensis and Catla catla were exposed to the concentrations of 0, 10, 20, 30, 40 and 50 mg/L of chromium for 96 h under static conditions for conducting acute toxicity tests. LC 50 was then calculated. The percentage cell survival was assessed by multiple endpoints such as MTT, NR, AB and CB assays in the seven fish cell lines exposed to different concentrations of chromium and EC 50 values of all the four endpoints were calculated. High significances were noted in the correlations between each in vitro cytotoxicity assays and in vivo mortality data. Cell shrinkage, cell detachment, vacuolations and cell swelling at the highest concentration of chromium (50 mg/L) were seen on microscopic examination of cell morphology. Comet assay and Hoechst staining were carried out to assess DNA damage and nuclear fragmentation in the seven fish lines exposed to chromium. The results of antioxidant parameters obtained indicate a significant reduction in the level of catalase, superoxide dismutase, glutathione S-transferase and Glutathione peroxidase, and increased level of lipid peroxidation in all the cell lines exposed to chromium. These results confirm that fish cell lines could be used as an alternative to whole fish for cytotoxicity, genotoxicity and oxidative stress assessment in chromium toxicity studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Duration Dependent Effect of Static Stretching on Quadriceps and Hamstring Muscle Force.

PubMed

Alizadeh Ebadi, Leyla; Çetin, Ebru

2018-03-13

The aim of this study was to determine the acute effect of static stretching on hamstring and quadriceps muscles' isokinetic strength when applied for various durations to elite athletes, to investigate the effect of different static stretching durations on isokinetic strength, and finally to determine the optimal stretching duration. Fifteen elite male athletes from two different sport branches (10 football and five basketball) participated in this study. Experimental protocol was designed as 17 repetitive static stretching exercises for hamstring and quadriceps muscle groups according to the indicated experimental protocols; ((A) 5 min jogging; (B) 5 min jogging followed by 15 s static stretching; (C) 5 min jogging followed by 30 s static stretching; (D) 5 min jogging, followed by static stretching for 45 s). Immediately after each protocol, an isokinetic strength test consisting of five repetitions at 60°/s speed and 20 repetitions at 180°/s speed was recorded for the right leg by the Isomed 2000 device. Friedman variance analysis test was employed for data analysis. According to the analyzes, it was observed that 5 min jogging and 15 s stretching exercises increased the isokinetic strength, whereas 30 and 45 s stretching exercises caused a decrease.

Duration Dependent Effect of Static Stretching on Quadriceps and Hamstring Muscle Force

PubMed Central

Çetin, Ebru

2018-01-01

The aim of this study was to determine the acute effect of static stretching on hamstring and quadriceps muscles’ isokinetic strength when applied for various durations to elite athletes, to investigate the effect of different static stretching durations on isokinetic strength, and finally to determine the optimal stretching duration. Fifteen elite male athletes from two different sport branches (10 football and five basketball) participated in this study. Experimental protocol was designed as 17 repetitive static stretching exercises for hamstring and quadriceps muscle groups according to the indicated experimental protocols; ((A) 5 min jogging; (B) 5 min jogging followed by 15 s static stretching; (C) 5 min jogging followed by 30 s static stretching; (D) 5 min jogging, followed by static stretching for 45 s). Immediately after each protocol, an isokinetic strength test consisting of five repetitions at 60°/s speed and 20 repetitions at 180°/s speed was recorded for the right leg by the Isomed 2000 device. Friedman variance analysis test was employed for data analysis. According to the analyzes, it was observed that 5 min jogging and 15 s stretching exercises increased the isokinetic strength, whereas 30 and 45 s stretching exercises caused a decrease.

Increased fall risk is associated with elevated co-contraction about the ankle during static balance challenges in older adults.

PubMed

Nelson-Wong, Erika; Appell, Ryan; McKay, Mike; Nawaz, Hannah; Roth, Joanna; Sigler, Robert; Third, Jacqueline; Walker, Mark

2012-04-01

Falls are a leading contributor to disability in older adults. Increased muscle co-contraction in the lower extremities during static and dynamic balance challenges has been associated with aging, and also with a history of falling. Co-contraction during static balance challenges has not been previously linked with performance on clinical tests designed to ascertain fall risk. The purpose of this study was to investigate the relationship between co-contraction about the ankle during static balance challenges with fall risk on a commonly used dynamic balance assessment, the Four Square Step Test (FSST). Twenty-three volunteers (mean age 73 years) performed a series of five static balance challenges (Romberg eyes open/closed, Sharpened Romberg eyes open/closed, and Single Leg Standing) with continuous electromyography (EMG) of bilateral tibialis anterior and gastrocnemius muscles. Participants then completed the FSST and were categorized as 'at-risk' or 'not-at-risk' to fall based on a cutoff time of 12 s. Co-contraction was quantified with co-contraction index (CCI). CCI during narrow base conditions was positively correlated with time to complete FSST. High CCIs during all static balance challenges with the exception of Romberg stance with eyes closed were predictive of being at-risk to fall based on FSST time, odds ratio 19.3. The authors conclude that co-contraction about the ankle during static balance challenges can be predictive of performance on a dynamic balance test.

An enriched stable-isotope approach to determine the gill-zinc binding properties of juvenile rainbow trout (Oncorhynchus mykiss) during acute zinc exposures in hard and soft waters

USGS Publications Warehouse

Todd, A.S.; Brinkman, S.; Wolf, R.E.; Lamothe, P.J.; Smith, K.S.; Ranville, J.F.

2009-01-01

The objective of the present study was to employ an enriched stable-isotope approach to characterize Zn uptake in the gills of rainbow trout (Oncorhynchus mykiss) during acute Zn exposures in hard water (???140 mg/L as CaCO 3) and soft water (???30 mg/L as CaCO3). Juvenile rainbow trout were acclimated to the test hardnesses and then exposed for up to 72 h in static exposures to a range of Zn concentrations in hard water (0-1,000 ??g/L) and soft water (0-250 ??g/L). To facilitate detection of new gill Zn from endogenous gill Zn, the exposure media was significantly enriched with 67Zn stable isotope (89.60% vs 4.1% natural abundance). Additionally, acute Zn toxicity thresholds (96-h median lethal concentration [LC50]) were determined experimentally through traditional, flow-through toxicity tests in hard water (580 ??g/L) and soft water (110 ??g/L). Following short-term (???3 h) exposures, significant differences in gill accumulation of Zn between hard and soft water treatments were observed at the three common concentrations (75, 150, and 250 ??g/L), with soft water gills accumulating more Zn than hard water gills. Short-term gill Zn accumulation at hard and soft water LC50s (45-min median lethal accumulation) was similar (0.27 and 0.20 ??g/g wet wt, respectively). Finally, comparison of experimental gill Zn accumulation, with accumulation predicted by the biotic ligand model, demonstrated that model output reflected short-term (<1 h) experimental gill Zn accumulation and predicted observed differences in accumulation between hard and soft water rainbow trout gills. Our results indicate that measurable differences exist in short-term gill Zn accumulation following acclimation and exposure in different water hardnesses and that short-term Zn accumulation appears to be predictive of Zn acute toxicity thresholds (96-h LC50s). ?? 2009 SETAC.

Experimental investigation of the subsonic high-altitude operation of the NASA Lewis 10- by 10-foot supersonic wind tunnel

NASA Technical Reports Server (NTRS)

Hughes, Christopher E.; Jeracki, Robert J.

1988-01-01

An experimental investigation was conducted in the NASA Lewis 10- by 10-Foot Supersonic Wind Tunnel during subsonic tunnel operation in the aerodynamic cycle to determine the test section flow characteristics near the Advanced Turboprop Project propeller model plane of rotation. The investigation used an eight-probe pitot static flow survey rake to measure total and static pressures at two locations in the wind tunnel: the test section and the bellmouth section (upstream of the two-dimensional flexible-wall nozzle). A cone angularity probe was used to measure any flow angularity in the test section. The evaluation was conducted at tunnel Mach numbers from 0.10 to 0.35 and at three operating altitudes from 2,000 to 50,000 ft. which correspond to tunnel reference total pressures from 1960 to 245 psfa, respectively. The results of this experimental investigation indicate a total-pressure loss area in the center of the test section and a static-pressure gradient from the test section centerline to the wall. These total and static pressure differences were observed at all tunnel operating altitudes and diminished at lower tunnel velocities. The total-pressure loss area was also found in the bellmouth section, which indicates that the loss mechanism is not the tunnel flexible-wall nozzle. The flow in the test section is essentially axial since very small flow angles were measured. The results also indicate that a correction to the tunnel total and static pressures must be applied in order to determine accurate freestream conditions at the test section centerline.

Static evaluation of a NAVSTAR Global Positioning System (GPS) (Magnavox Z-Set) receiver, May-September, 1979

DOT National Transportation Integrated Search

1980-05-01

The report documents the results of the static testing of a NAVSTAR Global Positioning System (GPS) single channel sequential receiver (Magnavox Z-Set). These tests were performed at the Coast Guard District 11 office in Long Beach, CA from May to Se...

14 CFR 23.681 - Limit load static tests.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of this... loading in the control system; and (2) Each fitting, pulley, and bracket used in attaching the system to...

14 CFR 23.681 - Limit load static tests.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of this... loading in the control system; and (2) Each fitting, pulley, and bracket used in attaching the system to...

14 CFR 23.681 - Limit load static tests.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of this... loading in the control system; and (2) Each fitting, pulley, and bracket used in attaching the system to...

14 CFR 23.681 - Limit load static tests.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of this... loading in the control system; and (2) Each fitting, pulley, and bracket used in attaching the system to...

14 CFR 23.681 - Limit load static tests.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.681 Limit load static tests. (a) Compliance with the limit load requirements of this... loading in the control system; and (2) Each fitting, pulley, and bracket used in attaching the system to...

19. HISTORIC VIEW OF MAX VALIER IN AN EARLY STATIC ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. HISTORIC VIEW OF MAX VALIER IN AN EARLY STATIC TEST. THE ROCKET IS SITTING ON A SCALE. VALIER IS MEASURING THRUST BY ADDING WEIGHT LIKE THE ONE IN HIS RIGHT HAND. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

Saturn Apollo Program

NASA Image and Video Library

1967-10-01

Workmen at the Marshall Space Flight Center's (MSFC's) dock on the Ternessee River unload S-IB-211, the flight version of the Saturn IB launch vehicle's first stage, from the NASA barge Palaemon. Between December 1967 and April 1968, the stage would undergo seven static test firings in MSFC's S-IB static test stand.

Saturn Apollo Program

NASA Image and Video Library

1967-10-01

Workmen at the Marshall Space Flight Center's (MSFC's) dock on the Ternessee River unload S-IB-211, the flight version of the Saturn IB launch vehicle's first stage, from the NASA barge Palaemon. Between December 1967 and April 1968, the stage would undergo seven static test firings in Marshall's S-IB static test stand.

Hyalella IQ Toxicity Test{trademark} as a predictor of whole sediment toxicity with diversely contaminated sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douglas, W.S.; Hayes, K.R.

1994-12-31

The IQ TOXICITY TEST{trademark} is a toxicity screening test that evaluates the organism`s galactosidase enzyme system functionality as a predictor of acute toxicity. Organisms are exposed to a potentially toxic solution for approximately one hour. Following the exposure, the organisms are exposed to a slurry of a galactoside sugar tagged with a fluorescent marker (methylumbelliferyl galactoside) for 15--20 minutes. A black light can then be used to examine whether the hemolymph of the organism contains free umbelliferone, which brightly fluoresces. The organisms are then scored as ``on`` or ``off`` with respect to free umbelliferone. This endpoint can then be usedmore » to calculate an EC50, which is comparable to a whole effluent, pure compound, or sediment toxicity test. Slightly different methodologies are used for different toxicity test organisms. The objective of this presentation is to discuss the use of the IQ{trademark} methodology with porewater extract exposures of the amphipod Hyalella azteca as a predictor of results of whole sediment toxicity tests. The results of over thirty 10 and 28-day whole sediment toxicity tests and the concurrent Hyalella azteca 10 TOXICITY TESTS{trademark} are compared and discussed. The use of screening tests as a reduced cost method for initial site assessment will be discussed.« less

Experimental studies on the tripping behavior of narrow T-stiffened flat plates subjected to hydrostatic pressure and underwater shock

NASA Technical Reports Server (NTRS)

Budweg, H. L.; Shin, Y. S.

1987-01-01

An experimental investigation was conducted to determine the static and dynamic responses of a specific stiffened flat plate design. The air-backed rectangular flat plates of 6061-T6 aluminum with an externally machined longitudinal narrow-flanged T-stiffener and clamped boundary conditions were subjected to static loading by water hydropump pressure and shock loading from an eight pound TNT charge detonated underwater. The dynamic test plate was instrumented to measure transient strains and free field pressure. The static test plate was instrumented to measure transient strains, plate deflection, and pressure. Emphasis was placed upon forcing static and dynamic stiffener tripping, obtaining relevant strain and pressure data, and studying the associated plate-stiffener behavior.

Measurement of the static and dynamic coefficients of a cross-type parachute in subsonic flow

NASA Technical Reports Server (NTRS)

Shpund, Zalman; Levin, Daniel

1991-01-01

An experimental parametric investigation of the aerodynamic qualities of cross-type parachutes was performed in a subsonic wind tunnel, using a new experimental technique. This investigation included the measurement of the static and dynamic aerodynamic coefficients, utilizing the measuring apparatus modified specifically for this type of testing. It is shown that the static aerodynamic coefficients of several configurations are in good agreement with available data, and assisted in validating the experimental technique employed. Two configuration parameters were varied in the static tests, the cord length and the canopy aspect ratio, with both parameters having a similar effect on the drag measurement, i.e., any increase in either of them increased the effective blocking area, and therefore the axial force.

Oriented Scintillation Spectrometer Experiment (OSSE). Revision A. Volume 1

DTIC Science & Technology

1988-05-19

SYSTEM-LEVEL ENVIRONMENTAL TESTS ................... 108 3.5.1 OPERATION REPORT, PROOF MODEL STRUCTURE TESTS.. .108 3.5.1.1 PROOF MODEL MODAL SURVEY...81 3-21 ALIGNMENT ERROR BUDGET, FOV, A4 ................ 82 3-22 ALIGNMENT ERROR BUDGET, ROTATION AXIS, A4 ...... 83 3-23 OSSE PROOF MODEL MODAL SURVEY...PROOF MODEL MODAL SURVEY .................. 112 3-27-1 OSSE PROOF MODEL STATIC LOAD TEST ............. 116 3-27-2 OSSE PROOF MODEL STATIC LOAD TEST

Saturn Apollo Program

NASA Image and Video Library

1964-10-01

Test firing of the Saturn I S-I Stage (S-1-10) at the Marshall Space Flight Center. This test stand was originally constructed in 1951 and sometimes called the Redstone or T tower. In l961, the test stand was modified to permit static firing of the S-I/S-IB stages, which produced a total thrust of 1,600,000 pounds. The name of the stand was then changed to the S-IB Static Test Stand.

Prevalidation of an Acute Inhalation Toxicity Test Using the EpiAirway In Vitro Human Airway Model

PubMed Central

Jackson, George R.; Maione, Anna G.; Klausner, Mitchell

2018-01-01

Abstract Introduction: Knowledge of acute inhalation toxicity potential is important for establishing safe use of chemicals and consumer products. Inhalation toxicity testing and classification procedures currently accepted within worldwide government regulatory systems rely primarily on tests conducted in animals. The goal of the current work was to develop and prevalidate a nonanimal (in vitro) test for determining acute inhalation toxicity using the EpiAirway™ in vitro human airway model as a potential alternative for currently accepted animal tests. Materials and Methods: The in vitro test method exposes EpiAirway tissues to test chemicals for 3 hours, followed by measurement of tissue viability as the test endpoint. Fifty-nine chemicals covering a broad range of toxicity classes, chemical structures, and physical properties were evaluated. The in vitro toxicity data were utilized to establish a prediction model to classify the chemicals into categories corresponding to the currently accepted Globally Harmonized System (GHS) and the Environmental Protection Agency (EPA) system. Results: The EpiAirway prediction model identified in vivo rat-based GHS Acute Inhalation Toxicity Category 1–2 and EPA Acute Inhalation Toxicity Category I–II chemicals with 100% sensitivity and specificity of 43.1% and 50.0%, for GHS and EPA acute inhalation toxicity systems, respectively. The sensitivity and specificity of the EpiAirway prediction model for identifying GHS specific target organ toxicity-single exposure (STOT-SE) Category 1 human toxicants were 75.0% and 56.5%, respectively. Corrosivity and electrophilic and oxidative reactivity appear to be the predominant mechanisms of toxicity for the most highly toxic chemicals. Conclusions: These results indicate that the EpiAirway test is a promising alternative to the currently accepted animal tests for acute inhalation toxicity. PMID:29904643

Prevalidation of an Acute Inhalation Toxicity Test Using the EpiAirway In Vitro Human Airway Model.

PubMed

Jackson, George R; Maione, Anna G; Klausner, Mitchell; Hayden, Patrick J

2018-06-01

Introduction: Knowledge of acute inhalation toxicity potential is important for establishing safe use of chemicals and consumer products. Inhalation toxicity testing and classification procedures currently accepted within worldwide government regulatory systems rely primarily on tests conducted in animals. The goal of the current work was to develop and prevalidate a nonanimal ( in vitro ) test for determining acute inhalation toxicity using the EpiAirway™ in vitro human airway model as a potential alternative for currently accepted animal tests. Materials and Methods: The in vitro test method exposes EpiAirway tissues to test chemicals for 3 hours, followed by measurement of tissue viability as the test endpoint. Fifty-nine chemicals covering a broad range of toxicity classes, chemical structures, and physical properties were evaluated. The in vitro toxicity data were utilized to establish a prediction model to classify the chemicals into categories corresponding to the currently accepted Globally Harmonized System (GHS) and the Environmental Protection Agency (EPA) system. Results: The EpiAirway prediction model identified in vivo rat-based GHS Acute Inhalation Toxicity Category 1-2 and EPA Acute Inhalation Toxicity Category I-II chemicals with 100% sensitivity and specificity of 43.1% and 50.0%, for GHS and EPA acute inhalation toxicity systems, respectively. The sensitivity and specificity of the EpiAirway prediction model for identifying GHS specific target organ toxicity-single exposure (STOT-SE) Category 1 human toxicants were 75.0% and 56.5%, respectively. Corrosivity and electrophilic and oxidative reactivity appear to be the predominant mechanisms of toxicity for the most highly toxic chemicals. Conclusions: These results indicate that the EpiAirway test is a promising alternative to the currently accepted animal tests for acute inhalation toxicity.

Static and wind tunnel near-field/far-field jet noise measurements from model scale single-flow baseline and suppressor nozzles. Volume 1: Noise source locations and extrapolation of static free-field jet noise data

NASA Technical Reports Server (NTRS)

Jaeck, C. L.

1976-01-01

A test was conducted in the Boeing Large Anechoic Chamber to determine static jet noise source locations of six baseline and suppressor nozzle models, and establish a technique for extrapolating near field data into the far field. The test covered nozzle pressure ratios from 1.44 to 2.25 and jet velocities from 412 to 594 m/s at a total temperature of 844 K.

Saturn Apollo Program

NASA Image and Video Library

1965-04-01

S-IB-1, the first flight version of the Saturn IB launch vehicle's first stage (S-IB stage), undergoes a full-duration static firing in Saturn IB static test stand at the Marshall Space Flight Center (MSFC) on April 13, 1965. Developed by the MSFC and built by the Chrysler Corporation at the Michoud Assembly Facility (MAF) in New Orleans, Louisiana, the 90,000-pound booster utilized eight H-1 engines to produce a combined thrust of 1,600,000 pounds. Between April 1965 and July 1968, MSFC performed thirty-two static tests on twelve different S-IB stages.

Criteria for structural test

NASA Technical Reports Server (NTRS)

1973-01-01

The results of a study to define criteria and techniques of design, analysis and test which permit the use of a single major structural test article for performing dynamic, fatigue, and static testing are presented. The criteria developed is applicable to both space vehicles and aircraft structures operating in the subsonic or supersonic regime. The feasibility of such an approach was demonstrated by defining test interactions, compatibilities and incompatibilities between the three different types of tests. The results of the study indicate that the single test article concept is feasible with a testing sequence of dynamic test followed by a fatigue and static test.

Evaluation of ability of reference toxicity tests to identify stress in laboratory populations of the amphipod Hyalella azteca

USGS Publications Warehouse

McNulty, E.W.; Dwyer, F.J.; Ellersieck, Mark R.; Greer, E.I.; Ingersoll, C.G.; Rabeni, C.F.

1999-01-01

Standard methods for conducting toxicity tests imply that the condition of test organisms can be established using reference toxicity tests. However, only a limited number of studies have evaluated whether reference toxicity tests can actually be used to determine if organisms are in good condition at the start of a test. We evaluated the ability of reference toxicants to identify stress associated with starvation in laboratory populations of the amphipod Hyalella azteca using acute toxicity tests and four reference toxicants: KCl, CdCl2, sodium pentachlorophenate (NaPCP), and carbaryl. Stress associated with severe starvation was observed with exposure of amphipods to carbaryl or NaPCP but not with exposure to KCl or CdCl2 (i.e., lower LC50 with severe starvation). Although the LC50s for NaPCP and carbaryl were statistically different between starved and fed amphipods, this difference may not be biologically significant given the variability expected in acute lethality tests. Stress associated with sieving, heat shock, or cold shock of amphipods before the start of a test was not evident with exposure to carbaryl or KCl as reference toxicants. The chemicals evaluated in this study provided minimal information about the condition of the organisms used to start a toxicity test. Laboratories should periodically perform reference toxicity tests to assess the sensitivity of life stages or strains of test organisms. However, use of other test acceptability criteria required in standard methods such as minimum survival, growth, or reproduction of organisms in the control treatment at the end of a test, provides more useful information about the condition of organisms used to start a test compared to data generated from reference toxicity tests.

Corrosion of dental nickel-aluminum bronze with a minor gold content-mechanism and biological impact.

PubMed

Ardlin, Berit I; Lindholm-Sethson, Britta; Dahl, Jon E

2009-02-01

To study corrosion and to evaluate biological effects in vitro of corrosion products of a copper-aluminum-nickel alloy with 2% gold. The alloy NPGtrade mark+2 with the nominal composition Cu:77.3; Al:7.8; Ni:4.3; Fe:3.0; Zn:2.7; Au:2.0; and Mn:1.7 was characterized. Static immersion in acidic saline, pH 2.2-2.4, was used to determine release of metallic elements in a milieu simulating the condition of plaque build-up in interproximal areas of the tooth. Corrosion and surface reactions in saline and artificial saliva were studied by electrochemical techniques including registration of open-circuit-potentials, polarization curves and impedance spectra. Extracts were made in cell culture media and acidic saline and used for MTT test for cytotoxicity and HET-CAM method for irritation. The mean amount of elements released in the acidic saline were in microg cm(-2) : Cu:632; Al:210; Ni:144; Fe:122; Zn:48; Mn:52. No protective film was formed on the surface of the alloy, as extensive corrosion was observed in both saline and artificial saliva. The corrosion rate was higher in saline than in artificial saliva. Acidic extracts of the alloy diluted up to 64 times reduced cell viability with 80% or more. The extract induced coagulation of the blood vessels of the CAM and was rated as moderate irritant solution. The nickel-aluminum bronze showed high corrosion rate caused by an inability to create a protective surface layer. High levels of toxic elements were found after static immersion testing, and the corrosion products had a distinct adverse effect on the biological activity. Copyright 2008 Wiley Periodicals, Inc.

Principles and Procedures for Evaluating the Toxicity of Household Substances. Revised.

ERIC Educational Resources Information Center

National Academy of Sciences - National Research Council, Washington, DC. Assembly of Life Sciences.

This report was prepared for use by the professional toxicologist. It contains chapters on ingestion exposure, dermal and dye toxicity tests, inhalation exposure, chronic toxicity and carcinogenicity tests, mutagenicity tests, reproduction and teratogenicity tests, and behavioral toxicity tests. In addition, regulations under the Federal Hazardous…

Relationship among aqueous copper half-lives and responses of Pimephales promelas to a series of copper sulfate pentahydrate concentrations.

PubMed

Calomeni, Alyssa J; Kinley, Ciera M; Geer, Tyler D; Iwinski, Kyla J; Hendrikse, Maas; Rodgers, John H

2018-04-01

Copper algaecide exposures in situ are often of shorter duration than exposures for static toxicity experiments because aqueous concentrations in situ dissipate as a function of site-specific fate processes. Consequently, responses of organisms to static copper exposures may overestimate effects following in situ exposures. To understand the role of exposure duration for altering responses, Pimephales promelas survival was compared following static (96 h) and pulse (1.5, 4, 8, and 15 h half-lives) exposures of CuSO 4 •5H 2 O. Copper concentrations sorbed by fry indicated a consequence of different exposures. Responses of P. promelas to static exposures resulted in 96 h LC 50 s of 166 µgCu/L (95% confidence interval [CI], 142-189 µgCu/L) as soluble copper and 162 µgCu/L (CI, 140-183 µgCu/L) as acid soluble copper. Relative to static 96 h LC 50 s, exposures with half-lives of 1.5, 4 and 8 h resulted in LC 50 s 10, 3 and 2 times greater, respectively, for responses measured 96 h after exposure initiation. Copper concentrations extracted from fry exposed for 1.5, 4 and 8 h half-lives were less than the static experiment. However, copper sorbed by fry in the 15 h half-life experiment was not different than the static experiment. The relationship between 96 h LC 50 and 1/half-life was expressed using the equations y = 116 + 1360 × (R 2  = 0.97) for soluble copper and y = 147 + 1620 × (R 2  = 0.98) for acid soluble copper. Incorporation of exposure duration for predictions of P. promelas responses to copper pulse exposures increases prediction accuracy by an order of magnitude.

On Restructurable Control System Theory

NASA Technical Reports Server (NTRS)

Athans, M.

1983-01-01

The state of stochastic system and control theory as it impacts restructurable control issues is addressed. The multivariable characteristics of the control problem are addressed. The failure detection/identification problem is discussed as a multi-hypothesis testing problem. Control strategy reconfiguration, static multivariable controls, static failure hypothesis testing, dynamic multivariable controls, fault-tolerant control theory, dynamic hypothesis testing, generalized likelihood ratio (GLR) methods, and adaptive control are discussed.

Static Thrust and Power Characteristics of Six Full-Scale Propellers

NASA Technical Reports Server (NTRS)

Hartman, Erwin P; Biermann, David

1940-01-01

Static thrust and power measurements were made of six full-scale propellers. The propellers were mounted in front of a liquid-cooled-engine nacelle and were tested at 15 different blade angles in the range from -7 1/2 degrees to 35 degrees at 0.75r. The test rig was located outdoors and the tests were made under conditions of approximately zero wind velocity.

Overview of the 6 Meter HIAD Inflatable Structure and Flexible TPS Static Load Test Series

NASA Technical Reports Server (NTRS)

Swanson, Greg; Kazemba, Cole; Johnson, Keith; Calomino, Anthony; Hughes, Steve; Cassell, Alan; Cheatwood, Neil

2014-01-01

To support NASAs long term goal of landing humans on Mars, technologies which enable the landing of heavy payloads are being developed. Current entry, decent, and landing technologies are not practical for this class of payloads due to geometric constraints dictated by current launch vehicle fairing limitations. Therefore, past and present technologies are now being explored to provide a mass and volume efficient solution to atmospheric entry, including Hypersonic Inflatable Aerodynamic Decelerators (HIADs). At the beginning of 2014, a 6m HIAD inflatable structure with an integrated flexible thermal protection system (TPS) was subjected to a static load test series to verify the designs structural performance. The 6m HIAD structure was constructed in a stacked toroid configuration using nine inflatable torus segments composed of fiber reinforced thin films, which were joined together using adhesives and high strength textile woven structural straps to help distribute the loads throughout the inflatable structure. The 6m flexible TPS was constructed using multiple layers of high performance materials to protect the inflatable structure from heat loads that would be seen during atmospheric entry. To perform the static load test series, a custom test fixture was constructed. The fixture consisted of a structural tub rim with enough height to allow for displacement of the inflatable structure as loads were applied. The bottom of the tub rim had an airtight seal with the floor. The centerbody of the inflatable structure was attached to a pedestal mount as seen in Figure 1. Using an impermeable membrane seal draped over the test article, partial vacuum was pulled beneath the HIAD, resulting in a uniform static pressure load applied to the outer surface. During the test series an extensive amount of instrumentation was used to provide many data sets including: deformed shape, shoulder deflection, strap loads, cord loads, inflation pressures, and applied static load.In this overview, the 6m HIAD static load test series will be discussed in detail, including the 6m HIAD inflatable structure and flexible TPS design, test setup and execution, and finally initial results and conclusions from the test series.

Scaling effects in the static and dynamic response of graphite-epoxy beam-columns. Ph.D. Thesis - Virginia Polytechnic Inst. and State Univ.

NASA Technical Reports Server (NTRS)

Jackson, Karen E.

1990-01-01

Scale model technology represents one method of investigating the behavior of advanced, weight-efficient composite structures under a variety of loading conditions. It is necessary, however, to understand the limitations involved in testing scale model structures before the technique can be fully utilized. These limitations, or scaling effects, are characterized. in the large deflection response and failure of composite beams. Scale model beams were loaded with an eccentric axial compressive load designed to produce large bending deflections and global failure. A dimensional analysis was performed on the composite beam-column loading configuration to determine a model law governing the system response. An experimental program was developed to validate the model law under both static and dynamic loading conditions. Laminate stacking sequences including unidirectional, angle ply, cross ply, and quasi-isotropic were tested to examine a diversity of composite response and failure modes. The model beams were loaded under scaled test conditions until catastrophic failure. A large deflection beam solution was developed to compare with the static experimental results and to analyze beam failure. Also, the finite element code DYCAST (DYnamic Crash Analysis of STructure) was used to model both the static and impulsive beam response. Static test results indicate that the unidirectional and cross ply beam responses scale as predicted by the model law, even under severe deformations. In general, failure modes were consistent between scale models within a laminate family; however, a significant scale effect was observed in strength. The scale effect in strength which was evident in the static tests was also observed in the dynamic tests. Scaling of load and strain time histories between the scale model beams and the prototypes was excellent for the unidirectional beams, but inconsistent results were obtained for the angle ply, cross ply, and quasi-isotropic beams. Results show that valuable information can be obtained from testing on scale model composite structures, especially in the linear elastic response region. However, due to scaling effects in the strength behavior of composite laminates, caution must be used in extrapolating data taken from a scale model test when that test involves failure of the structure.

Propfan test assessment propfan propulsion system static test report

NASA Technical Reports Server (NTRS)

Orourke, D. M.

1987-01-01

The propfan test assessment (PTA) propulsion system successfully completed over 50 hours of extensive static ground tests, including a 36 hour endurance test. All major systems performed as expected, verifying that the large-scale 2.74 m diameter propfan, engine, gearbox, controls, subsystems, and flight instrumentation will be satisfactory with minor modifications for the upcoming PTA flight tests on the GII aircraft in early 1987. A test envelope was established for static ground operation to maintain propfan blade stresses within limits for propfan rotational speeds up to 105 percent and power levels up to 3880 kW. Transient tests verified stable, predictable response of engine power and propfan speed controls. Installed engine TSFC was better than expected, probably due to the excellent inlet performance coupled with the supercharging effect of the propfan. Near- and far-field noise spectra contained three dominant components, which were dependent on power, tip speed, and direction. The components were propfan blade tones, propfan random noise, and compressor/propfan interaction noise. No significant turbine noise or combustion noise was evident.

A procedure obtaining stiffnesses and masses of a structure from vibration modes and substructure static test data

NASA Technical Reports Server (NTRS)

Edighoffer, H. H.

1979-01-01

A component mode desynthesis procedure is developed for determining the unknown vibration characteristics of a structural component (i.e., a launch vehicle) given the vibration characteristics of a structural system composed of that component combined with a known one (i.e., a payload). At least one component static test has to be performed. These data are used in conjunction with the system measured frequencies and mode shapes to obtain the vibration characteristics of each component. The flight dynamics of an empty launch vehicle can be determined from measurements made on a vehicle/payload combination in conjunction with a static test on the payload.

Dynamic testing in schizophrenia: does training change the construct validity of a test?

PubMed

Wiedl, Karl H; Schöttke, Henning; Green, Michael F; Nuechterlein, Keith H

2004-01-01

Dynamic testing typically involves specific interventions for a test to assess the extent to which test performance can be modified, beyond level of baseline (static) performance. This study used a dynamic version of the Wisconsin Card Sorting Test (WCST) that is based on cognitive remediation techniques within a test-training-test procedure. From results of previous studies with schizophrenia patients, we concluded that the dynamic and static versions of the WCST should have different construct validity. This hypothesis was tested by examining the patterns of correlations with measures of executive functioning, secondary verbal memory, and verbal intelligence. Results demonstrated a specific construct validity of WCST dynamic (i.e., posttest) scores as an index of problem solving (Tower of Hanoi) and secondary verbal memory and learning (Auditory Verbal Learning Test), whereas the impact of general verbal capacity and selective attention (Verbal IQ, Stroop Test) was reduced. It is concluded that the construct validity of the test changes with dynamic administration and that this difference helps to explain why the dynamic version of the WCST predicts functional outcome better than the static version.

Effect of hardness on acute toxicity of metal mixtures using Daphnia magna: prediction of acid mine drainage toxicity.

PubMed

Yim, Jin Hee; Kim, Kyoung W; Kim, Sang D

2006-11-02

In this study, the effect of hardness on the combined outcome of metal mixtures was investigated using Daphnia magna. The toxic unit (TU) was calculated using modified LC(50) values based on the hardness (i.e., LC(50-soft) and LC(50-hard)). From a bioassay test, the degree of sensitivity to hardness on the toxicity changes was in the order: Cd

Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models.

PubMed

Teng, S; Tebby, C; Barcellini-Couget, S; De Sousa, G; Brochot, C; Rahmani, R; Pery, A R R

2016-08-15

Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro - in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

Acute And Subchronic Toxicity Studies Of SNEDDS (Self Nanoemulsifying Drug Delivery Systems) From Ethyl Acetate Extract Of Bay Leaf (Eugenia polyantha W.) with Virgin Coconut Oil As Oil Phase

NASA Astrophysics Data System (ADS)

Prihapsara, F.; Alamsyah, R. I.; Widiyani, T.; Artanti, A. N.

2018-03-01

Bay leaf (Eugenia polyantha) is widely used as an alternative therapy for diabetic and hypercholesterol. However, the administration of the extract has a low oral bioavailability, therefore it is prepared by Self Nanoemulsifying Drug Delivery Systems (SNEDDS) ethyl acetate extract of bay leaf. Therefore, acute and subchronic toxicity test is required. The toxicity test performed was an experimental study, including acute and subchronic toxicity tests. Animal experiments were used using Wistar strain rats. Acute toxicity test using 5 groups (n=5) consisted of 1 control group and 4 groups of SNEDDS dose with 48 mg/kgBW 240 mg/kg, 1200 mg/kg, and 6000 mg/kg, while for subchronic toxicity test with 1 group control and 3 groups of doses of SNEDDS with dose group variation 91.75 mg/kgBW, 183.5 mg/kg, and 367 mg/kg. Duration of observation at acute toxicity test for 14 days while for subcronic toxicity test for 28 days with continuous SNEDDS dosage. The results of the acute toxicity test showed toxic symptoms and obtained median lethal dose (LD50) values from SNEDDS from ethyl acetate extract of bay leaf 1409.30 mg/kgBW belonging to slightly toxic category. Subchronic toxicity studies show that the test drug has minor damage in liver and kidneys and moderate damage in pancreas.

Influence of Mixed Mode I-Mode II Loading on Fatigue Delamination Growth Characteristics of a Graphite Epoxy Tape Laminate

NASA Technical Reports Server (NTRS)

Ratcliffe, James G.; Johnston, William M., Jr.

2014-01-01

Mixed mode I-mode II interlaminar tests were conducted on IM7/8552 tape laminates using the mixed-mode bending test. Three mixed mode ratios, G(sub II)/G(sub T) = 0.2, 0.5, and 0.8, were considered. Tests were performed at all three mixed-mode ratios under quasi-static and cyclic loading conditions, where the former static tests were used to determine initial loading levels for the latter fatigue tests. Fatigue tests at each mixed-mode ratio were performed at four loading levels, Gmax, equal to 0.5G(sub c), 0.4G(sub c), 0.3G(sub c), and 0.2G(sub c), where G(sub c) is the interlaminar fracture toughness of the corresponding mixed-mode ratio at which a test was performed. All fatigue tests were performed using constant-amplitude load control and delamination growth was automatically documented using compliance solutions obtained from the corresponding quasi-static tests. Static fracture toughness data yielded a mixed-mode delamination criterion that exhibited monotonic increase in Gc with mixed-mode ratio, G(sub II)/G(sub T). Fatigue delamination onset parameters varied monotonically with G(sub II)/G(sub T), which was expected based on the fracture toughness data. Analysis of non-normalized data yielded a monotonic change in Paris law exponent with mode ratio. This was not the case when normalized data were analyzed. Fatigue data normalized by the static R-curve were most affected in specimens tested at G(sub II)/G(sub T)=0.2 (this process has little influence on the other data). In this case, the normalized data yielded a higher delamination growth rate compared to the raw data for a given loading level. Overall, fiber bridging appeared to be the dominant mechanism, affecting delamination growth rates in specimens tested at different load levels and differing mixed-mode ratios.

Flight-test data on the static fore-and-aft stability of various German airplanes

NASA Technical Reports Server (NTRS)

Hubner, Walter

1933-01-01

The static longitudinal stability of an airplane with locked elevator is usually determined by analysis and model tests. The present report proposes to supply the results of such measurements. The method consisted of recording the dynamic pressure versus elevator displacement at different center-of-gravity positions in unaccelerated flight.

40 CFR Appendix 1 to Subpart A of... - Static Sheen Test (EPA Method 1617)

Code of Federal Regulations, 2014 CFR

2014-07-01

... free oil” requirement for discharges of drilling fluids, drill cuttings, produced sand, and well... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Static Sheen Test (EPA Method 1617) 1 Appendix 1 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...

40 CFR Appendix 1 to Subpart A of... - Static Sheen Test (EPA Method 1617)

Code of Federal Regulations, 2013 CFR

2013-07-01

... free oil” requirement for discharges of drilling fluids, drill cuttings, produced sand, and well... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Static Sheen Test (EPA Method 1617) 1 Appendix 1 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...

40 CFR Appendix 1 to Subpart A of... - Static Sheen Test (EPA Method 1617)

Code of Federal Regulations, 2012 CFR

2012-07-01

... free oil” requirement for discharges of drilling fluids, drill cuttings, produced sand, and well... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Static Sheen Test (EPA Method 1617) 1 Appendix 1 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...

Static and wind tunnel model tests for the development of externally blown flap noise reduction techniques

NASA Technical Reports Server (NTRS)

Pennock, A. P.; Swift, G.; Marbert, J. A.

1975-01-01

Externally blown flap models were tested for noise and performance at one-fifth scale in a static facility and at one-tenth scale in a large acoustically-treated wind tunnel. The static tests covered two flap designs, conical and ejector nozzles, third-flap noise-reduction treatments, internal blowing, and flap/nozzle geometry variations. The wind tunnel variables were triple-slotted or single-slotted flaps, sweep angle, and solid or perforated third flap. The static test program showed the following noise reductions at takeoff: 1.5 PNdB due to treating the third flap; 0.5 PNdB due to blowing from the third flap; 6 PNdB at flyover and 4.5 PNdB in the critical sideline plane (30 deg elevation) due to installation of the ejector nozzle. The wind tunnel program showed a reduction of 2 PNdB in the sideline plane due to a forward speed of 43.8 m/s (85 kn). The best combination of noise reduction concepts reduced the sideline noise of the reference aircraft at constant field length by 4 PNdB.

Structural integrity of a confinement vessel for testing nuclear fuels for space propulsion

NASA Astrophysics Data System (ADS)

Bergmann, V. L.

Nuclear propulsion systems for rockets could significantly reduce the travel time to distant destinations in space. However, long before such a concept can become reality, a significant effort must be invested in analysis and ground testing to guide the development of nuclear fuels. Any testing in support of development of nuclear fuels for space propulsion must be safely contained to prevent the release of radioactive materials. This paper describes analyses performed to assess the structural integrity of a test confinement vessel. The confinement structure, a stainless steel pressure vessel with bolted flanges, was designed for operating static pressures in accordance with the ASME Boiler and Pressure Vessel Code. In addition to the static operating pressures, the confinement barrier must withstand static overpressures from off-normal conditions without releasing radioactive material. Results from axisymmetric finite element analyses are used to evaluate the response of the confinement structure under design and accident conditions. For the static design conditions, the stresses computed from the ASME code are compared with the stresses computed by the finite element method.

Cyclic fatigue resistance of ProTaper Universal instruments when subjected to static and dynamic tests.

PubMed

Lopes, Hélio P; Britto, Izabelle M O; Elias, Carlos N; Machado de Oliveira, Julio C; Neves, Mônica A S; Moreira, Edson J L; Siqueira, José F

2010-09-01

This study evaluated the number of cycles to fracture of ProTaper Universal S2 instruments when subjected to static and dynamic cyclic fatigue tests. ProTaper Universal S2 instruments were used until fracture in an artificial curved canal under rotational speed of 300 rpm in either a static or a dynamic test model. Afterward, the length of the fractured segments was measured and fractured surfaces and helical shafts analyzed by scanning electron microscopy (SEM). The number of cycles to fracture was significantly increased when instruments were tested in the dynamic model (P<.001). Instrument separation occurred at the point of maximum flexure within the artificial canals, i.e., the midpoint of the curved canal segment. SEM analysis revealed that fractured surfaces exhibited characteristics of the ductile mode. Plastic deformation was not observed in the helical shaft of fractured instruments. The number of cycles to fracture ProTaper Universal S2 instruments significantly increased with the use of instruments in a dynamic cyclic fatigue test compared with a static model. These findings reinforce the need for performing continuous pecking motions during rotary instrumentation of curved root canals. Copyright (c) 2010 Mosby, Inc. All rights reserved.

Effect of yoga training on one leg standing and functional reach tests in obese individuals with poor postural control

PubMed Central

Jorrakate, Chaiyong; Kongsuk, Jutaluk; Pongduang, Chiraprapa; Sadsee, Boontiwa; Chanthorn, Phatchari

2015-01-01

[Purpose] The aim of the present study was to investigate the effect of yoga training on static and dynamic standing balance in obese individuals with poor standing balance. [Subjects and Methods] Sixteen obese volunteers were randomly assigned into yoga and control groups. The yoga training program was performed for 45 minutes per day, 3 times per week, for 4 weeks. Static and dynamic balance were assessed in volunteers with one leg standing and functional reach tests. Outcome measures were tested before training and after a single week of training. Two-way repeated measure analysis of variance with Tukey’s honestly significant difference post hoc statistics was used to analyze the data. [Results] Obese individuals showed significantly increased static standing balance in the yoga training group, but there was no significant improvement of static or dynamic standing balance in the control group after 4 weeks. In the yoga group, significant increases in static standing balance was found after the 2nd, 3rd, and 4th weeks. Compared with the control group, static standing balance in the yoga group was significantly different after the 2nd week, and dynamic standing balance was significantly different after the 4th week. [Conclusion] Yoga training would be beneficial for improving standing balance in obese individuals with poor standing balance. PMID:25642038

View looking north west showing the boom, top of the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View looking north west showing the boom, top of the center mast and boom angle reeving of the 175-ton derrick. Note in the background of the view, just above the center mast is the F-1 Static-Test Stand used for test firing the Saturn V engines and subsequent program's engine testing. Also in the background center is the Redstone Static Test Stand (center right) and it's cold calibration tower (center left). - Marshall Space Flight Center, Saturn V Dynamic Test Facility, East Test Area, Huntsville, Madison County, AL

A Comparison of the Quasi-static Mechanical and Nonlinear Viscoelastic Properties of the Human Semitendinosus and Gracilis Tendons

PubMed Central

Abramowitch, Steven D.; Zhang, Xiaoyan; Curran, Molly; Kilger, Robert

2010-01-01

Background Over fifty-percent of anterior cruciate ligament reconstructions are performed using semitendinosus and gracilis tendon autografts. Despite their increased use, there remains little quantitative data on their mechanical behavior. Therefore, the objective of this study was to investigate the quasi-static mechanical and nonlinear viscoelastic properties of human semitendinosus and gracilis tendons, as well as the variation of these properties along their length. Methods Specimens were subjected to a series of uniaxial tensile tests: one-hour static stress-relaxation test, 30-cycle cyclic stress-relaxation test and load to failure test. To describe the nonlinear viscoelastic behavior, the quasi-linear viscoelastic theory was utilized to model data from the static stress relaxation experiment. Findings The constants describing the viscoelastic behavior were similar between the proximal and distal halves of the gracilis tendon. The proximal half of the semitendinosus tendon, however, had a greater viscous response than its distal half, which was also significantly higher than the proximal gracilis tendon. In terms of the quasi-static mechanical properties, the properties were similar between the proximal and distal halves of the semitendinosus tendon. However, the distal gracilis tendon showed a significantly higher tangent modulus and ultimate stress compared to its proximal half, which was also significantly higher than the distal semitendinosus tendon. Interpretation The results of this study demonstrate differences between the semitendinosus and gracilis tendons in terms of their quasi-static mechanical and nonlinear viscoelastic properties. These results are important for establishing surgical preconditioning protocols and graft selection. PMID:20092917

Optimization of Hyalella azteca IQ Toxicity Test{trademark} for prediction of 28-day sediment toxicity tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novotny, A.N.; Ezzard, C.L.; Douglas, W.S.

1995-12-31

The IQ Toxicity Test, which is a rapid screening toxicity test consisting of the observation of in-vivo inhibition of an enzymatic process using a fluorescent substrate, has proven successful for the determination of 24 and 48-hour EC50`s of D. magna, C. dubia, D. pulex and M. bahia. The application of this concept to utilize the freshwater amphipod Hyalella azteca may be an excellent way in which to reduce the standard 28-day chronic sediment toxicity test to possibly one hour`s time. This study incorporates an additive experimental design to explore the effects of and interactions between five specific variables: size ofmore » the amphipod, exposure time to the toxicant, concentration of substrate, exposure time to the substrate, and length of time starved prior to testing. The results of the IQ toxicity test were compared to those of a 28-day chronic sediment toxicity test. Preliminary data indicate that there is an optimal combination of these variables which results in a concise, reproducible toxicity test for use with Hyalella azteca, and would potentially be applicable to other freshwater amphipods in the future.« less

SEDIMENT TOXICITY ASSESSMENT: COMPARISON OF STANDARD AND NEW TESTING DESIGNS

EPA Science Inventory

Standard methods of sediment toxicity testing are fairly well accepted; however, as with all else, evolution of these methods is inevitable. We compared a standard ASTM 10-day amphipod toxicity testing method with smaller, 48- and 96-h test methods using very toxic and reference ...

Static and dynamic strain energy release rates in toughened thermosetting composite laminates

NASA Technical Reports Server (NTRS)

Cairns, Douglas S.

1992-01-01

In this work, the static and dynamic fracture properties of several thermosetting resin based composite laminates are presented. Two classes of materials are explored. These are homogeneous, thermosetting resins and toughened, multi-phase, thermosetting resin systems. Multi-phase resin materials have shown enhancement over homogenous materials with respect to damage resistance. The development of new dynamic tests are presented for composite laminates based on Width Tapered Double Cantilevered Beam (WTDCB) for Mode 1 fracture and the End Notched Flexure (ENF) specimen. The WTDCB sample was loaded via a low inertia, pneumatic cylinder to produce rapid cross-head displacements. A high rate, piezo-electric load cell and an accelerometer were mounted on the specimen. A digital oscilloscope was used for data acquisition. Typical static and dynamic load versus displacement plots are presented. The ENF specimen was impacted in three point bending with an instrumented impact tower. Fracture initiation and propagation energies under static and dynamic conditions were determined analytically and experimentally. The test results for Mode 1 fracture are relatively insensitive to strain rate effects for the laminates tested in this study. The test results from Mode 2 fracture indicate that the toughened systems provide superior fracture initiation and higher resistance to propagation under dynamic conditions. While the static fracture properties of the homogeneous systems may be relatively high, the apparent Mode 2 dynamic critical strain energy release rate drops significantly. The results indicate that static Mode 2 fracture testing is inadequate for determining the fracture performance of composite structures subjected to conditions such as low velocity impact. A good correlation between the basic Mode 2 dynamic fracture properties and the performance is a combined material/structural Compression After Impact (CAI) test is found. These results underscore the importance of examining rate-dependent behavior for determining the longevity of structures manufactured from composite materials.

A comparison of two reciprocating instruments using bending stress and cyclic fatigue tests.

PubMed

Scelza, Pantaleo; Harry, Davidowicz; Silva, Licinio Esmeraldo da; Barbosa, Igor Bastos; Scelza, Miriam Zaccaro

2015-01-01

The aim of this study was to comparatively evaluate the bending resistance at 45º, the static and dynamic cyclic fatigue life, and the fracture type of the WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) 25-08 and Reciproc (VDW, Munich, Germany) 25-08 instruments. A total of 60 nickel-titanium (NiTi) instruments (30 Reciproc and 30 WaveOne) from three different lots, each of which was 25 mm in length, were tested. The bending resistance was evaluated through the results of a cantilever-bending test conducted using a universal testing machine. Static and dynamic cyclic fatigue testing was conducted using a custom-made device. For the static and dynamic tests, a cast Ni-Cr-Mo-Ti alloy metal block with an artificial canal measuring 1.77 mm in diameter and 20.00 mm in total length was used. A scanning electron microscope was used to determine the type of fracture. Statistical analyses were performed on the results. The WaveOne instrument was less flexible than the Reciproc (p < 0.05). The Reciproc instrument showed better resistance in the static and dynamic cyclic fatigue tests (p < 0.05). The transverse cross-section and geometry of the instruments were important factors in their resistance to bending and cyclic fracture. Both of the instruments showed ductile-type fracture characteristics. It can be concluded that the Reciproc 25-08 instrument was more resistant to static and dynamic cyclic fatigue than the WaveOne 25-08 instrument, while the WaveOne 25-08 instrument was less flexible. Bending and resistance to cyclic fracture were influenced by the instruments' geometries and transverse cross-sections. Both of the instruments showed ductile-type fracture characteristics.

Static and dynamic balance of children and adolescents with sensorineural hearing loss.

PubMed

Melo, Renato de Souza; Marinho, Sônia Elvira Dos Santos; Freire, Maryelly Evelly Araújo; Souza, Robson Arruda; Damasceno, Hélio Anderson Melo; Raposo, Maria Cristina Falcão

2017-01-01

To assess the static and dynamic balance performance of students with normal hearing and with sensorineural hearing loss. A cross-sectional study assessing 96 students, 48 with normal hearing and 48 with sensorineural hearing loss of both sexes, aged 7 and 18 years. To evaluate static balance, Romberg, Romberg-Barré and Fournier tests were used; and for the dynamic balance, we applied the Unterberger test. Hearing loss students showed more changes in static and dynamic balance as compared to normal hearing, in all tests used (p<0.001). The same difference was found when subjects were grouped by sex. For females, Romberg, Romberg-Barré, Fournier and Unterberger test p values were, respectively, p=0.004, p<0.001, p<0.001 and p=0.023; for males, the p values were p=0.009, p<0.001, p<0.001 and p=0.002, respectively. The same difference was observed when students were classified by age. For 7 to 10 years old students, the p values for Romberg, Romberg-Barré and Fournier tests were, respectively, p=0.007, p<0.001 and p=0.001; for those aged 11 and 14 years, the p values for Romberg, Romberg-Barré, Fournier and Unterberger tests were p=0.002, p<0.001, p<0.001 and p=0.015, respectively; and for those aged 15 and 18 years, the p values for Romberg-Barré, Fournier and Unterberger tests were, respectively, p=0.037, p<0.001 and p=0.037. Hearing-loss students showed more changes in static and dynamic balance comparing to normal hearing of same sex and age groups.

Acute effects of static stretching on peak and end-range hamstring-to-quadriceps functional ratios.

PubMed

Sekir, Ufuk; Arabaci, Ramiz; Akova, Bedrettin

2015-10-18

To evaluate if static stretching influences peak and end-range functional hamstring-to-quadriceps (H/Q) strength ratios in elite women athletes. Eleven healthy female athletes in an elite competitive level participated to the study. All the participants fulfilled the static stretching or non-stretching (control) intervention protocol in a randomized design on different days. Two static unassisted stretching exercises, one in standing and one in sitting position, were used to stretch both the hamstring and quadriceps muscles during these protocols. The total time for the static stretching was 6 ± 1 min. The isokinetic peak torque measurements for the hamstring and quadriceps muscles in eccentric and concentric modes and the calculations for the functional H/Q strength ratios at angular velocities of 60°/s and 180°/s were made before (pre) and after (post) the control or stretching intervention. The strength measurements and functional strength ratio calculations were based during the entire- and end-range of knee extension. The pre-test scores for quadriceps and hamstring peak torque and end range values were not significantly different between the groups (P > 0.05). Subsequently, although the control group did not exhibit significant changes in quadriceps and hamstring muscle strength (P > 0.05), static stretching decreased eccentric and concentric quadriceps muscle strength at both the 60°/s and 180°/s test speeds (P < 0.01). Similarly, static stretching also decreased eccentric and concentric hamstring muscle strength at both the 60°/s and 180°/s test speeds (P < 0.01). On the other hand, when the functional H/Q strength ratios were taken into consideration, the pre-intervention values were not significant different between the groups both during the entire and end range of knee extension (P > 0.05). Furthermore, the functional H/Q strength ratios exhibited no significant alterations during the entire and end ranges of knee extension both in the static stretching or the control intervention (P > 0.05). According to our results, static stretching routine does not influence functional H/Q ratio. Athletes can confidently perform static stretching during their warm-up routines.

Acute effects of static stretching on peak and end-range hamstring-to-quadriceps functional ratios

PubMed Central

Sekir, Ufuk; Arabaci, Ramiz; Akova, Bedrettin

2015-01-01

AIM: To evaluate if static stretching influences peak and end-range functional hamstring-to-quadriceps (H/Q) strength ratios in elite women athletes. METHODS: Eleven healthy female athletes in an elite competitive level participated to the study. All the participants fulfilled the static stretching or non-stretching (control) intervention protocol in a randomized design on different days. Two static unassisted stretching exercises, one in standing and one in sitting position, were used to stretch both the hamstring and quadriceps muscles during these protocols. The total time for the static stretching was 6 ± 1 min. The isokinetic peak torque measurements for the hamstring and quadriceps muscles in eccentric and concentric modes and the calculations for the functional H/Q strength ratios at angular velocities of 60°/s and 180°/s were made before (pre) and after (post) the control or stretching intervention. The strength measurements and functional strength ratio calculations were based during the entire- and end-range of knee extension. RESULTS: The pre-test scores for quadriceps and hamstring peak torque and end range values were not significantly different between the groups (P > 0.05). Subsequently, although the control group did not exhibit significant changes in quadriceps and hamstring muscle strength (P > 0.05), static stretching decreased eccentric and concentric quadriceps muscle strength at both the 60°/s and 180°/s test speeds (P < 0.01). Similarly, static stretching also decreased eccentric and concentric hamstring muscle strength at both the 60°/s and 180°/s test speeds (P < 0.01). On the other hand, when the functional H/Q strength ratios were taken into consideration, the pre-intervention values were not significant different between the groups both during the entire and end range of knee extension (P > 0.05). Furthermore, the functional H/Q strength ratios exhibited no significant alterations during the entire and end ranges of knee extension both in the static stretching or the control intervention (P > 0.05). CONCLUSION: According to our results, static stretching routine does not influence functional H/Q ratio. Athletes can confidently perform static stretching during their warm-up routines. PMID:26495249

ELECTRICAL AND ELECTRONIC INDUSTRIAL CONTROL, STATIC CONTROL SERIES. BASIC CONTROL FUNCTIONS, UNIT 9A.

ERIC Educational Resources Information Center

SUTTON, MACK C.

THIS SELF-INSTRUCTIONAL PROGRAMED TEXT IS FOR INDIVIDUAL STUDENT USE IN STUDYING STATIC CONTROL IN ELECTRICAL-ELECTRONIC PROGRAMS. IT WAS DEVELOPED BY AN INSTRUCTIONAL MATERIALS SPECIALIST AND ADVISERS AND HAS BEEN TESTED BY STUDENT USE. THE OBJECTIVE OF THE COURSE IS TO HELP THE ELECTRICAL-TECHNICIAN DEVELOP AN UNDERSTANDING OF STATIC CONTROL…

Microstructural evolution of a superaustenitic stainless steel during a two-step deformation process

NASA Astrophysics Data System (ADS)

Bayat, N.; Ebrahimi, G. R.; Momeni, A.; Ezatpour, H. R.

2018-02-01

Single- and two-step hot compression experiments were carried out on 16Cr25Ni6Mo superaustenitic stainless steel in the temperature range from 950 to 1150°C and at a strain rate of 0.1 s-1. In the two-step tests, the first pass was interrupted at a strain of 0.2; after an interpass time of 5, 20, 40, 60, or 80 s, the test was resumed. The progress of dynamic recrystallization at the interruption strain was less than 10%. The static softening in the interpass period increased with increasing deformation temperature and increasing interpass time. The static recrystallization was found to be responsible for fast static softening in the temperature range from 950 to 1050°C. However, the gentle static softening at 1100 and 1150°C was attributed to the combination of static and metadynamic recrystallizations. The correlation between calculated fractional softening and microstructural observations showed that approximately 30% of interpass softening could be attributed to the static recovery. The microstructural observations illustrated the formation of fine recrystallized grains at the grain boundaries at longer interpass time. The Avrami kinetics equation was used to establish a relationship between the fractional softening and the interpass period. The activation energy for static softening was determined as 276 kJ/mol.

16 CFR 1500.40 - Method of testing toxic substances.

Code of Federal Regulations, 2010 CFR

2010-01-01

... bleeding. (c) Procedures for testing. The sleeve is slipped onto the animal which is then placed in a... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Method of testing toxic substances. 1500.40... testing toxic substances. The method of testing the toxic substances referred to in § 1500.3(c) (1)(ii)(C...

16 CFR 1500.40 - Method of testing toxic substances.

Code of Federal Regulations, 2012 CFR

2012-01-01

... bleeding. (c) Procedures for testing. The sleeve is slipped onto the animal which is then placed in a... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Method of testing toxic substances. 1500.40... testing toxic substances. The method of testing the toxic substances referred to in § 1500.3(c) (1)(ii)(C...

16 CFR 1500.40 - Method of testing toxic substances.

Code of Federal Regulations, 2011 CFR

2011-01-01

... bleeding. (c) Procedures for testing. The sleeve is slipped onto the animal which is then placed in a... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Method of testing toxic substances. 1500.40... testing toxic substances. The method of testing the toxic substances referred to in § 1500.3(c) (1)(ii)(C...

Alphabus Mechanical Validation Plan and Test Campaign

NASA Astrophysics Data System (ADS)

Calvisi, G.; Bonnet, D.; Belliol, P.; Lodereau, P.; Redoundo, R.

2012-07-01

A joint team of the two leading European satellite companies (Astrium and Thales Alenia Space) worked with the support of ESA and CNES to define a product line able to efficiently address the upper segment of communications satellites : Alphabus Starting in 2009 and up to 2011 the mechanical validation of the Alphabus platform has been obtained thanks to static tests performed on dedicated static model and to environmental test performed on the first satellite based on Alphabus: Alphasat I-XL. The mechanical validation of the Alphabus platform presented an excellent opportunity to improve the validation and qualification process, with respect to static, sine vibrations, acoustic and L/V shock environment, minimizing recurrent cost of manufacturing, integration and testing. A main driver on mechanical testing is that mechanical acceptance testing at satellite level will be performed with empty tanks due to technical constraints (limitation of existing vibration devices) and programmatic advantages (test risk reduction, test schedule minimization). In this paper the impacts that such testing logic have on validation plan are briefly recalled and its actual application for Alphasat PFM mechanical test campaign is detailed.

A SURROGATE SUBCHRONIC TOXICITY TEST METHOD FOR WATERS WITH HIGH TOTAL DISSOLVED SOLIDS

EPA Science Inventory

Total dissolved solids (TDS) are often identified as a toxicant in whole-effluent toxicity (WET) testing. The primary test organism used in WET testing, Ceriodaphnia dubia, is very sensitive to TDS ions, which can be problematic when differentiating the toxicity of TDS from those...

Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.

PubMed

Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene

2015-07-01

The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests. © 2015 SETAC.

Detailed study of water quality, bottom sediment, and biota associated with irrigation drainage in the Klamath Basin, California and Oregon, 1990-92

USGS Publications Warehouse

Dileanis, Peter D.; Schwarzbach, S.E.; Bennett, Jewel

1996-01-01

The effect of irrigation drainage on the water quality and wildlife of the Klamath Basin in California and Oregon was evaluated during 1990-92 as part of the National Irrigation Water Quality Program of the U.S. Department of the Interior. The study focused on land serviced by the Bureau of Reclamation Klamath Project, which supplies irrigation water to agricultural land in the Klamath Basin and the Lost River Basin. The Tule Lake and Lower Klamath National Wildlife Refuges, managed by the U.S. Fish and Wildlife Service, are in the study area. These refuges provide critical resting and breeding habitat for waterfowl on the Pacific flyway and are dependent on irrigation drainwater from upstream agriculture for most of their water supply. Water-quality characteristics throughout the study area were typical of highly eutrophic systems during the summer months of 1991 and 1992. Dissolved-oxygen concentrations and pH tended to fluctuate each day in response to diurnal patterns of photosynthesis, and frequently exceeded criteria for protection of aquatic organisms. Nitrogen and phosphorus concentrations were generally at or above threshold levels characteristic of eutrophic lakes and streams. At most sites the bulk of dissolved nitrogen was organically bound. Elevated ammonia concentrations were common in the study area, especially down- stream of drain inputs. High pH of water increased the toxicity of ammonia, and concentrations exceeded criteria at sites upstream and downstream of irrigated land. Concentrations of ammonia in samples from small drains on the Tule Lake refuge leaseland were higher than those measured in the larger, integrating drains at primary monitoring sites. The mean ammonia concentration in leaseland drains [1.21 milligrams per liter (mg/L)] was significantly higher than the mean concentration in canals delivering water to the leaseland fields (0.065 mg/L) and higher than concentrations reported to be lethal to Daphnia magna (median lethal concentration of 0.66 mg/L). Dissolved- oxygen concentrations also were lower, and Daphnia survivability measured during in situ bioassays was correspondingly lower in the leaseland drains than in water delivery canals. In static laboratory bioassays, water samples collected at the primary monitoring sites caused toxicity in up to 78 percent of Lemna minor tests, in up to 49 percent of Xenopus laevis tests, in 17 percent and 8 percent of Hyalella azteca and Pimephales promelas tests, respectively, and 0 percent in Daphnia magna tests. In situ exposure at the sites caused mortality in more than 83 percent of Pimephales tests and in more than 41 percent of Daphnia and Hyalella tests. Much of the observed toxicity appears to have been caused by low dissolved oxygen, high pH, and ammonia. Although water in the study area was toxic to a variety of organisms, no statistically significant differences in the degree of toxicity between sites were observed above or below irrigated agricultural land in any of the bioassays. Pesticides were frequently detected in water samples collected at the monitoring sites during the 1991 and 1992 irrigation seasons. Among the most frequently detected compounds were the herbicides simazine, metribuzin, EPTC, and metolachlor and the insecticide terbufos. All the insecticides detected were at concentrations substantially below acute toxicity values reported for aquatic organisms. The herbicide acrolein has been used extensively in the basin to manage aquatic plant growth in irrigation canals and drains. The concentration of acrolein was monitored in a canal near Tule Lake after an application in order to evaluate the potential for the pesticide to be transported to refuge waters. Although acrolein concentrations were toxic to fish in the channels adjacent to Tule Lake, very little of the canal water entered the refuge during the monitoring period. Organochlorine pesticide concentrations in 25 surficial sediment samples collected in 1990 were below bas

Flight effects on noise by the JT8D engine with inverted primary/fan flow as measured in the NASA-Ames 40 by 80 foot wind tunnel

NASA Technical Reports Server (NTRS)

Strout, F. G.

1978-01-01

A JT8D-17R engine with inverted primary and fan flows was tested under static conditions as well as in the NASA Ames 40 by 80 Foot Wind Tunnel to determine static and flight noise characteristics, and flow profile of a large scale engine. Test and analysis techniques developed by a previous model and JT8D engine test program were used to determine the in-flight noise. The engine with inverted flow was tested with a conical nozzle and with a plug nozzle, 20 lobe nozzle, and an acoustic shield. Wind tunnel results show that forward velocity causes significant reduction in peak PNL suppression relative to uninverted flow. The loss of EPNL suppression is relatively modest. The in-flight peak PNL suppression of the inverter with conical nozzle was 2.5 PNdb relative to a static value of 5.5 PNdb. The corresponding EPNL suppression was 4.0 EPNdb for flight and 5.0 EPNdb for static operation. The highest in-flight EPNL suppression was 7.5 EPNdb obtained by the inverter with 20 lobe nozzle and acoustic shield. When compared with the JT8D engine with internal mixer, the inverted flow configuration provides more EPNL suppression under both static and flight conditions.

Study on Finite Element Model Updating in Highway Bridge Static Loading Test Using Spatially-Distributed Optical Fiber Sensors

PubMed Central

Wu, Bitao; Lu, Huaxi; Chen, Bo; Gao, Zhicheng

2017-01-01

A finite model updating method that combines dynamic-static long-gauge strain responses is proposed for highway bridge static loading tests. For this method, the objective function consisting of static long-gauge stains and the first order modal macro-strain parameter (frequency) is established, wherein the local bending stiffness, density and boundary conditions of the structures are selected as the design variables. The relationship between the macro-strain and local element stiffness was studied first. It is revealed that the macro-strain is inversely proportional to the local stiffness covered by the long-gauge strain sensor. This corresponding relation is important for the modification of the local stiffness based on the macro-strain. The local and global parameters can be simultaneously updated. Then, a series of numerical simulation and experiments were conducted to verify the effectiveness of the proposed method. The results show that the static deformation, macro-strain and macro-strain modal can be predicted well by using the proposed updating model. PMID:28753912

Study on Finite Element Model Updating in Highway Bridge Static Loading Test Using Spatially-Distributed Optical Fiber Sensors.

PubMed

Wu, Bitao; Lu, Huaxi; Chen, Bo; Gao, Zhicheng

2017-07-19

A finite model updating method that combines dynamic-static long-gauge strain responses is proposed for highway bridge static loading tests. For this method, the objective function consisting of static long-gauge stains and the first order modal macro-strain parameter (frequency) is established, wherein the local bending stiffness, density and boundary conditions of the structures are selected as the design variables. The relationship between the macro-strain and local element stiffness was studied first. It is revealed that the macro-strain is inversely proportional to the local stiffness covered by the long-gauge strain sensor. This corresponding relation is important for the modification of the local stiffness based on the macro-strain. The local and global parameters can be simultaneously updated. Then, a series of numerical simulation and experiments were conducted to verify the effectiveness of the proposed method. The results show that the static deformation, macro-strain and macro-strain modal can be predicted well by using the proposed updating model.

Quasi-Static Calibration Method of a High-g Accelerometer

PubMed Central

Wang, Yan; Fan, Jinbiao; Zu, Jing; Xu, Peng

2017-01-01

To solve the problem of resonance during quasi-static calibration of high-g accelerometers, we deduce the relationship between the minimum excitation pulse width and the resonant frequency of the calibrated accelerometer according to the second-order mathematical model of the accelerometer, and improve the quasi-static calibration theory. We establish a quasi-static calibration testing system, which uses a gas gun to generate high-g acceleration signals, and apply a laser interferometer to reproduce the impact acceleration. These signals are used to drive the calibrated accelerometer. By comparing the excitation acceleration signal and the output responses of the calibrated accelerometer to the excitation signals, the impact sensitivity of the calibrated accelerometer is obtained. As indicated by the calibration test results, this calibration system produces excitation acceleration signals with a pulse width of less than 1000 μs, and realize the quasi-static calibration of high-g accelerometers with a resonant frequency above 20 kHz when the calibration error was 3%. PMID:28230743

Static internal performance of convergent single-expansion-ramp nozzles with various combinations of internal geometric parameters

NASA Technical Reports Server (NTRS)

Bare, E. Ann; Capone, Francis J.

1989-01-01

An investigation was conducted in the Static Test Facility of the Langley 16-Foot Transonic Tunnel to determine the effects of five geometric design parameters on the internal performance of convergent single expansion ramp nozzles. The effects of ramp chordal angle, initial ramp angle, flap angle, flap length, and ramp length were determined. All nozzles tested has a nominally constant throat area and aspect ratio. Static pressure distributions along the centerlines of the ramp and flap were also obtained for each configuration. Nozzle pressure ratio was varied up to 10.0 for all configurations.

Static internal performance of a two-dimensional convergent-divergent nozzle with thrust vectoring

NASA Technical Reports Server (NTRS)

Bare, E. Ann; Reubush, David E.

1987-01-01

A parametric investigation of the static internal performance of multifunction two-dimensional convergent-divergent nozzles has been made in the static test facility of the Langley 16-Foot Transonic Tunnel. All nozzles had a constant throat area and aspect ratio. The effects of upper and lower flap angles, divergent flap length, throat approach angle, sidewall containment, and throat geometry were determined. All nozzles were tested at a thrust vector angle that varied from 5.60 tp 23.00 deg. The nozzle pressure ratio was varied up to 10 for all configurations.

Classification of baseline toxicants for QSAR predictions to replace fish acute toxicity studies.

PubMed

Nendza, Monika; Müller, Martin; Wenzel, Andrea

2017-03-22

Fish acute toxicity studies are required for environmental hazard and risk assessment of chemicals by national and international legislations such as REACH, the regulations of plant protection products and biocidal products, or the GHS (globally harmonised system) for classification and labelling of chemicals. Alternative methods like QSARs (quantitative structure-activity relationships) can replace many ecotoxicity tests. However, complete substitution of in vivo animal tests by in silico methods may not be realistic. For the so-called baseline toxicants, it is possible to predict the fish acute toxicity with sufficient accuracy from log K ow and, hence, valid QSARs can replace in vivo testing. In contrast, excess toxicants and chemicals not reliably classified as baseline toxicants require further in silico, in vitro or in vivo assessments. Thus, the critical task is to discriminate between baseline and excess toxicants. For fish acute toxicity, we derived a scheme based on structural alerts and physicochemical property thresholds to classify chemicals as either baseline toxicants (=predictable by QSARs) or as potential excess toxicants (=not predictable by baseline QSARs). The step-wise approach identifies baseline toxicants (true negatives) in a precautionary way to avoid false negative predictions. Therefore, a certain fraction of false positives can be tolerated, i.e. baseline toxicants without specific effects that may be tested instead of predicted. Application of the classification scheme to a new heterogeneous dataset for diverse fish species results in 40% baseline toxicants, 24% excess toxicants and 36% compounds not classified. Thus, we can conclude that replacing about half of the fish acute toxicity tests by QSAR predictions is realistic to be achieved in the short-term. The long-term goals are classification criteria also for further groups of toxicants and to replace as many in vivo fish acute toxicity tests as possible with valid QSAR predictions.

40 CFR 799.5085 - Chemical testing requirements for first group of high production volume chemicals (HPV1).

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Acute Toxicity to Daphnia: ASTM E 729 3. Toxicity to Plants (Algae): ASTM E 1218 Test Group 2 for C1: 1. Chronic Toxicity to Daphnia: ASTM E 1193 2. Toxicity to Plants (Algae): ASTM E 1218 The following are the... conditions. Test Group 1 for C2: 1. Acute Toxicity to Daphnia: ASTM E 729 2. Toxicity to Plants (Algae): ASTM...

40 CFR 799.5085 - Chemical testing requirements for first group of high production volume chemicals (HPV1).

Code of Federal Regulations, 2013 CFR

2013-07-01

.... Acute Toxicity to Daphnia: ASTM E 729 3. Toxicity to Plants (Algae): ASTM E 1218 Test Group 2 for C1: 1. Chronic Toxicity to Daphnia: ASTM E 1193 2. Toxicity to Plants (Algae): ASTM E 1218 The following are the... conditions. Test Group 1 for C2: 1. Acute Toxicity to Daphnia: ASTM E 729 2. Toxicity to Plants (Algae): ASTM...

Ecological impacts of lead mining on Ozark streams: toxicity of sediment and pore water.

PubMed

Besser, John M; Brumbaugh, William G; Allert, Ann L; Poulton, Barry C; Schmitt, Christopher J; Ingersoll, Christopher G

2009-02-01

We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daphnids in most pore waters tested. Additional amphipod tests conducted in 2004 documented significant toxic effects of sediments from three streams downstream of mining areas: Strother Creek, West Fork Black River, and Bee Fork. Greatest toxicity occurred in sediments from a 6-km reach of upper Strother Creek, but significant toxic effects occurred in sediments collected at least 14 km downstream of mining in all three watersheds. Toxic effects were significantly correlated with metal concentrations (nickel, zinc, cadmium, and lead) in sediments and pore waters and were generally consistent with predictions of metal toxicity risks based on sediment quality guidelines, although ammonia and manganese may also have contributed to toxicity at a few sites. Responses of amphipods in sediment toxicity tests were significantly correlated with characteristics of benthic invertebrate communities in study streams. These results indicate that toxicity of metals associated with sediments contributes to adverse ecological effects in streams draining the Viburnum Trend mining district.

Ecological impacts of lead mining on Ozark streams: Toxicity of sediment and pore water

USGS Publications Warehouse

Besser, J.M.; Brumbaugh, W.G.; Allert, A.L.; Poulton, B.C.; Schmitt, C.J.; Ingersoll, C.G.

2009-01-01

We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daphnids in most pore waters tested. Additional amphipod tests conducted in 2004 documented significant toxic effects of sediments from three streams downstream of mining areas: Strother Creek, West Fork Black River, and Bee Fork. Greatest toxicity occurred in sediments from a 6-km reach of upper Strother Creek, but significant toxic effects occurred in sediments collected at least 14 km downstream of mining in all three watersheds. Toxic effects were significantly correlated with metal concentrations (nickel, zinc, cadmium, and lead) in sediments and pore waters and were generally consistent with predictions of metal toxicity risks based on sediment quality guidelines, although ammonia and manganese may also have contributed to toxicity at a few sites. Responses of amphipods in sediment toxicity tests were significantly correlated with characteristics of benthic invertebrate communities in study streams. These results indicate that toxicity of metals associated with sediments contributes to adverse ecological effects in streams draining the Viburnum Trend mining district.

Mechanism of acute silver toxicity in Daphnia magna.

PubMed

Bianchini, Adalto; Wood, Chris M

2003-06-01

Daphnids (Daphnia magna) were exposed to AgNO3 at 0.303 +/- 0.017 microg silver/L (46.9% as Ag+), in the absence of food, in moderately hard synthetic water under static conditions for up to 48 h. Results from accumulation experiments demonstrated that silver body burden was inversely related to body mass. Daphnids exposed to silver exhibited ionoregulatory disturbance, which was characterized by decreases in whole-body sodium concentration. This ionoregulatory disturbance was explained, at least in part, by a competitive inhibition of the whole-body sodium uptake (six- to sevenfold increase in the Michaelis constant with no change in maximal velocity), which was complete by 1 h of exposure, and resulted in approximately 40% inhibition of sodium influx from the water. A rapidly developing inhibition of whole-body Na+,K(+)-dependent adenosine triphosphatase (Na+,K(+)-ATPase) activity, significant by 2 h and complete at 90% blockade by 12 h, also was observed during exposure to AgNO3. Therefore, these findings clearly demonstrate that the key mechanism involved in acute Ag+ toxicity in D. magna, the most sensitive freshwater organism tested to date, resembles that described for freshwater fish--that is, inhibition of active sodium uptake by blockade of Na+,K(+)-ATPase. Furthermore, the results showed that Na+,K(+)-ATPase inhibition was directly related to silver accumulation in the whole body of D. magna. However, the nature of the sodium uptake inhibition (competitive vs noncompetitive in fish) and the fact that whole-body chloride concentration was not disturbed in daphnids was different from fish. With regard to the biotic ligand model (BLM) for silver, our results yielded a log K value of about 8.9. However, the current version of the BLM uses a rainbow trout log K value (7.3) but achieves the correct sensitivity of the model for daphnids by reducing the saturation of toxic sites needed to cause toxicity. An alternative way may be to use the log K value derived from the present results.

Predicting toxic effects of copper on aquatic biota in mineralized areas by using the Biotic Ligand Model

USGS Publications Warehouse

Smith, Kathleen S.; Ranville, James F.; Adams, M.; Choate, LaDonna M.; Church, Stan E.; Fey, David L.; Wanty, Richard B.; Crock, James G.

2006-01-01

The chemical speciation of metals influences their biological effects. The Biotic Ligand Model (BLM) is a computational approach to predict chemical speciation and acute toxicological effects of metals on aquatic biota. Recently, the U.S. Environmental Protection Agency incorporated the BLM into their regulatory water-quality criteria for copper. Results from three different laboratory copper toxicity tests were compared with BLM predictions for simulated test-waters. This was done to evaluate the ability of the BLM to accurately predict the effects of hardness and concentrations of dissolved organic carbon (DOC) and iron on aquatic toxicity. In addition, we evaluated whether the BLM and the three toxicity tests provide consistent results. Comparison of BLM predictions with two types of Ceriodaphnia dubia toxicity tests shows that there is fairly good agreement between predicted LC50 values computed by the BLM and LC50 values determined from the two toxicity tests. Specifically, the effect of increasing calcium concentration (and hardness) on copper toxicity appears to be minimal. Also, there is fairly good agreement between the BLM and the two toxicity tests for test solutions containing elevated DOC, for which the LC50 is 3-to-5 times greater (less toxic) than the LC50 for the lower-DOC test water. This illustrates the protective effects of DOC on copper toxicity and demonstrates the ability of the BLM to predict these protective effects. In contrast, for test solutions with added iron there is a decrease in LC50 values (increase in toxicity) in results from the two C. dubia toxicity tests, and the agreement between BLM LC50 predictions and results from these toxicity tests is poor. The inability of the BLM to account for competitive iron binding to DOC or DOC fractionation may be a significant shortcoming of the BLM for predicting site- specific water-quality criteria in streams affected by iron-rich acidic drainage in mined and mineralized areas.

Investigation of Acute and Chronic Toxicity Trends of Pesticides Using High-Throughput Bioluminescence Assay Based on the Test Organism Vibrio fischeri.

PubMed

Westlund, Paul; Nasuhoglu, Deniz; Isazadeh, Siavash; Yargeau, Viviane

2018-05-01

High-throughput acute and chronic toxicity tests using Vibrio fischeri were used to assess the toxicity of a variety of fungicides, herbicides, and neonicotinoids. The use of time points beyond the traditional 30 min of an acute test highlighted the sensitivity and applicability of the chronic toxicity test and indicated that for some compounds toxicity is underestimated using only the acute test. The comparison of EC 50 values obtained from acute and chronic tests provided insight regarding the toxicity mode of action, either being direct or indirect. Using a structure-activity relationship approach similar to the one used in hazard assessments, the relationship between toxicity and key physicochemical properties of pesticides was investigated and trends were identified. This study not only provides new information regarding acute toxicity of some pesticides but also is one of the first studies to investigate the chronic toxicity of pesticides using the test organism V. fischeri. The findings demonstrated that the initial bioluminescence has a large effect on the calculated effective concentrations for target compounds in both acute and chronic tests, providing a way to improve and standardize the test protocol. In addition, the findings emphasize the need for additional investigation regarding the relationship between a toxicant's physicochemical properties and mode of action in nontarget organisms.

A unique facility for V/STOL aircraft hover testing. [Langley Impact Dynamics Research Facility

NASA Technical Reports Server (NTRS)

Culpepper, R. G.; Murphy, R. D.; Gillespie, E. A.; Lane, A. G.

1979-01-01

The Langley Impact Dynamics Research Facility (IDRF) was modified to obtain static force and moment data and to allow assessment of aircraft handling qualities during dynamic tethered hover flight. Test probe procedures were also established. Static lift and control measurements obtained are presented along with results of limited dynamic tethered hover flight.

78 FR 78467 - Office of Commercial Space Transportation; Notice of Intent to Prepare an Environmental Impact...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-26

... persons regarding the FAA's intent to prepare an EIS that will evaluate the potential environmental... launches per year (12 launches per vertical launch facility), as well as up to 24 static fire engine tests or wet dress rehearsals per year (12 static fire engine tests or wet dress rehearsals per vertical...

A Factor Analytic Validation Study of the Scale of Teachers' Attitudes towards Inclusive Classrooms (STATIC)

ERIC Educational Resources Information Center

Nishimura, Trisha Sugita; Busse, Randy T.

2015-01-01

General and special education teachers (N = 125) completed the Scale of Teachers' Attitudes towards Inclusive Classrooms (STATIC). The internal consistency of the instrument was strong with an alpha of 0.89. The measure demonstrated excellent test-retest reliability (r = 0.99) and a dependent t-test was non-significant, indicating mean group…

A STUDY OF DISPLACEMENT-LEVEL DEPENDENCY OF VERTICAL STIFFNESS OF PILE - COMPARISONS BETWEEN STATIC LOADING TEST AND MEASUREMENTS DURING TRAIN PASSING -

NASA Astrophysics Data System (ADS)

Nihei, Tatsuya; Nishioka, Hidetoshi; Kawamura, Chikara; Nishimura, Masahiro; Edamatsu, Masayuki; Koda, Masayuki

In order to introduce the performance based design of pile foundation, vertical stiffness of pile is one of the important design factors. Although it had been es timated the vertical stiffness of pile had the displacement-level dependency, it had been not clarified. We compared the vertical stiffness of pile measured by two loading conditions at pile foundation of the railway viaduct. Firstly, we measured the vertical stiffness at static loading test under construction of the viaduct. Secondly, we measured the vertical stiffness at the time of train passing. So, we recognized that the extrapolation of the displacement level dependency in static loading test could evaluate the vertical stiffness of pile during train passing.

Simulation of Flight-Type Engine Fan Noise in the NASA-Lewis 9X15 Anechoic Wind Tunnel

NASA Technical Reports Server (NTRS)

Heidmann, M. F.; Dietrich, D. A.

1976-01-01

Flight type noise as contrasted to the usual ground static test noise exhibits substantial reductions in the time unsteadiness of tone noise, and in the mean level of tones calculated to be nonpropagating or cut-off. A model fan designed with cuttoff of the fundamental tone was acoustically tested in the anechoic wind tunnel under both static and tunnel flow conditions. The properties that characterize flight type noise were progressively simulated with increasing tunnel flow. The distinctly lobed directivity pattern of propagating rotor/stator interaction modes was also observed. Excess noise attributed to the ingestion of the flow disturbances that prevail near most static test facilities is substantially reduced with tunnel flow.

Soft errors in commercial off-the-shelf static random access memories

NASA Astrophysics Data System (ADS)

Dilillo, L.; Tsiligiannis, G.; Gupta, V.; Bosser, A.; Saigne, F.; Wrobel, F.

2017-01-01

This article reviews state-of-the-art techniques for the evaluation of the effect of radiation on static random access memory (SRAM). We detailed irradiation test techniques and results from irradiation experiments with several types of particles. Two commercial SRAMs, in 90 and 65 nm technology nodes, were considered as case studies. Besides the basic static and dynamic test modes, advanced stimuli for the irradiation tests were introduced, as well as statistical post-processing techniques allowing for deeper analysis of the correlations between bit-flip cross-sections and design/architectural characteristics of the memory device. Further insight is provided on the response of irradiated stacked layer devices and on the use of characterized SRAM devices as particle detectors.

The flow field of an underexpanded H2 jet coaxially injected into a hot free or ducted supersonic jet of air or nitrogen

NASA Technical Reports Server (NTRS)

Jenkins, R. V.

1977-01-01

Experimental data obtained in an investigation of the mixing of an underexpanded hydrogen jet in a supersonic flow both with and without combustion are presented. Tests were conducted in a Mach 2 test stream with both air and nitrogen as test media. Total temperature of the test stream was 2170 K, and static exit pressure was about one atmosphere. The static pressure at the exit of the hydrogen injector's Mach 2 nozzle was about two atmospheres. Primary measurements included shadowgraphs and pitot pressure surveys of the flow field. Pitot surveys and wall static pressures were measured for the case where the entire flow was shrouded. The results are compared to similar experimental data and theoretical predictions for the matched pressure case.

Static Corrosion Test of Porous Iron Material with Polymer Coating

NASA Astrophysics Data System (ADS)

Markušová-Bučková, Lucia; Oriňaková, Renáta; Oriňak, Andrej; Gorejová, Radka; Kupková, Miriam; Hrubovčáková, Monika; Baláž, Matej; Kováľ, Karol

2016-12-01

At present biodegradable implants received increased attention due to their use in various fields of medicine. This work is dedicated to testing of biodegradable materials which could be used as bone implants. The samples were prepared from the carbonyl iron powder by replication method and surface polymer film was produced through sol-gel process. Corrosion testing was carried out under static conditions during 12 weeks in Hank's solution. The quantity of corrosion products increased with prolonging time of static test as it can be concluded from the results of EDX analysis. The degradation of open cell materials with polyethylene glycol coating layer was faster compared to uncoated Fe sample. Also the mass losses were higher for samples with PEG coating. The polymer coating brought about the desired increase in degradation rate of porous iron material.

Trasonic Cascade Wind Tunnel Modification and Initial Tests.

DTIC Science & Technology

1980-06-01

27.57 Mathr 1.432 la No. 2 t S atic Pressure = 14.040 P.-ptg= .2686 Mach= 1.510 laz~r t~o. 29 Static Pressure= 13.946 p.ptO .26f2 Macha 1.513 T tp...54 Mach = 1.475 3. Ho. 45 Static Pressure t 12.811 PPto= .2451 Mach = 1.572 Tap No. 46 Static Pressures 12.563 P/Ptow .2403 Macha 1.586 Table c-i...T al) tNo. 64 Static Pressure- 11.981 P,/PtO= .2292 Macha 1.61:3 Twi:. No. 65 Static Pressure= 11.726 P’PtG= .2243 Mach= 1.632 af l N. 66 Sttatic

40 CFR 799.9355 - TSCA reproduction/developmental toxicity screening test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... toxicity screening test. 799.9355 Section 799.9355 Protection of Environment ENVIRONMENTAL PROTECTION... AND MIXTURE TESTING REQUIREMENTS Health Effects Test Guidelines § 799.9355 TSCA reproduction/developmental toxicity screening test. (a) Scope—(1) Applicability. This section is intended to meet testing...

40 CFR 799.9355 - TSCA reproduction/developmental toxicity screening test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... toxicity screening test. 799.9355 Section 799.9355 Protection of Environment ENVIRONMENTAL PROTECTION... AND MIXTURE TESTING REQUIREMENTS Health Effects Test Guidelines § 799.9355 TSCA reproduction/developmental toxicity screening test. (a) Scope—(1) Applicability. This section is intended to meet testing...

Alternative methods for toxicity assessments in fish: comparison of the fish embryo toxicity and the larval growth and survival tests in zebrafish and fathead minnows.

PubMed

Jeffries, Marlo K Sellin; Stultz, Amy E; Smith, Austin W; Rawlings, Jane M; Belanger, Scott E; Oris, James T

2014-11-01

An increased demand for chemical toxicity evaluations has resulted in the need for alternative testing strategies that address animal welfare concerns. The fish embryo toxicity (FET) test developed for zebrafish (Danio rerio) is one such alternative, and the application of the FET test to other species such as the fathead minnow (Pimephales promelas) has been proposed. In the present study, the performances of the FET test and the larval growth and survival (LGS; a standard toxicity testing method) test in zebrafish and fathead minnows were evaluated. This required that testing methods for the fathead minnow FET and zebrafish LGS tests be harmonized with existing test methods and that the performance of these testing strategies be evaluated by comparing the median lethal concentrations of 2 reference toxicants, 3,4-dicholoraniline and ammonia, obtained via each of the test types. The results showed that procedures for the zebrafish FET test can be adapted and applied to the fathead minnow. Differences in test sensitivity were observed for 3,4-dicholoraniline but not ammonia; therefore, conclusions regarding which test types offer the least or most sensitivity could not be made. Overall, these results show that the fathead minnow FET test has potential as an alternative toxicity testing strategy and that further analysis with other toxicants is warranted in an effort to better characterize the sensitivity and feasibility of this testing strategy. © 2014 SETAC.

Site Specific Metal Criteria Developed Using Kentucky Division of Water Procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kszos, L.A.; Phipps, T.L.

1999-10-09

Alternative limits for Cu, Ni, Pb, and Zn were developed for treated wastewater from four outfalls at a Gaseous Diffusion Plant. Guidance from the Kentucky Division of Water (KDOW) was used to (1) estimate the toxicity of the effluents using water fleas (Ceriodaphnia dubia) and fathead minnow (Pimephales promelas) larvae; (2) determine total recoverable and dissolved concentrations of Cu, Pb, Ni, and Zn ; (3) calculate ratios of dissolved metal (DM) to total recoverable metal (TRM); and (4) assess chemical characteristics of the effluents. Three effluent samples from each outfall were collected during each of six test periods; thus, amore » total of 18 samples from each outfall were evaluated for toxicity, DM and TRM. Subsamples were analyzed for alkalinity, hardness, pH, conductivity, and total suspended solids. Short-term (6 or 7 d), static renewal toxicity tests were conducted according to EPA methodology. Ceriodaphnia reproduction was reduced in one test of effluent from Outfall A , and effluent from Outfall B was acutely toxic to both test species during one test. However, the toxicity was not related to the metals present in the effluents. Of the 18 samples from each outfall, more than 65% of the metal concentrations were estimated quantities. With the exception of two total recoverable Cu values in Outfall C, all metal concentrations were below the permit limits and the federal water quality criteria. Ranges of TR for all outfalls were: Cd, ,0.1-0.4 {micro}g/L; Cr,1.07-3.93 {micro}g/L; Cu, 1.59-7.24 {micro}g/L; Pb, <0.1-3.20 {micro}g/L; Ni, 0.82-10.7 {micro}g/L, Zn, 4.75-67.3 {micro}g/L. DM:TRM ratios were developed for each outfall. The proportion of dissolved Cu in the effluents ranged from 67 to 82%; the proportion of dissolved Ni ranged from 84 to 91%; and the proportion of dissolved Zn ranged from 74 to 94%. The proportion of dissolved Pb in the effluents was considerably lower (37-51%). TRM and/or DM concentrations of Cu, Ni, Pb, or Zn differed significantly from outfall to outfall but the DM:TRM ratios for Cu, Ni, and Pb did not. Through the use of the KDOW method, the total recoverable metal measured in an effluent is adjusted by the proportion of dissolved metal present. The resulting alternative total recoverable metal concentration is reported in lieu of the measured total recoverable concentration for determining compliance with permit limits. For example, the monthly average permit limit for Pb in Outfall B (3 {micro}g/L) was exceeded at the Gaseous Diffusion Plant. Through the use of the KDOW method for calculating an alternative total recoverable metal concentration, 4.98 {micro}g Pb/L in Outfall B would be reported as 3.00 {micro}g/L, a difference of > 39%. Thus, the alternative, calculated total recoverable metal concentration provides the discharger with a ''cushion'' for meeting permit limits.« less

Predictions of sediment toxicity using consensus-based freshwater sediment quality guidelines

USGS Publications Warehouse

Ingersoll, C.G.; MacDonald, D.D.; Wang, N.; Crane, J.L.; Field, L.J.; Haverland, P.S.; Kemble, N.E.; Lindskoog, R.A.; Severn, C.; Smorong, D.E.

2001-01-01

The objectives of this study were to compare approaches for evaluating the combined effects of chemical mixtures on the toxicity in field-collected sediments and to evaluate the ability of consensus-based probable effect concentrations (PECs) to predict toxicity in a freshwater database on both a national and regional geographic basis. A database was developed from 92 published reports, which included a total of 1,657 samples with high-quality matching sediment toxicity and chemistry data from across North America. The database was comprised primarily of 10- to 14-day or 28- to 42-day toxicity tests with the amphipod Hyalella azteca (designated as the HA10 or HA28 tests) and 10- to 14-day toxicity tests with the midges Chironomus tentans or C. riparius (designated as the CS10 test). Mean PEC quotients were calculated to provide an overall measure of chemical contamination and to support an evaluation of the combined effects of multiple contaminants in sediments. There was an overall increase in the incidence of toxicity with an increase in the mean quotients in all three tests. A consistent increase in the toxicity in all three tests occurred at a mean quotient > 0.5, however, the overall incidence of toxicity was greater in the HA28 test compared to the short-term tests. The longer-term tests, in which survival and growth are measured, tend to be more sensitive than the shorter-term tests, with acute to chronic ratios on the order of six indicated for H. azteca. Different patterns were observed among the various procedures used to calculate mean quotients. For example, in the HA28 test, a relatively abrupt increase in toxicity was associated with elevated polychlorinated biphenyls (PCBs) alone or with elevated polycyclic aromatic hydrocarbons (PAHs) alone, compared to the pattern of a gradual increase in toxicity observed with quotients calculated using a combination of metals, PAHs, and PCBs. These analyses indicate that the different patterns in toxicity may be the result of unique chemical signals associated with individual contaminants in samples. Though mean quotients can be used to classify samples as toxic or nontoxic, individual quotients might be useful in helping identify substances that may be causing or substantially contributing to the observed toxicity. An increase in the incidence of toxicity was observed with increasing mean quotients within most of the regions, basins, and areas in North America for all three toxicity tests. The results of these analyses indicate that the consensus-based PECs can be used to reliably predict toxicity of sediments on both a regional and national basis.

Structural Testing of a 6m Hypersonic Inflatable Aerodynamic Decelerator System

NASA Technical Reports Server (NTRS)

Swanson, G. T.; Kazemba, C. D.; Johnson, R. K.; Hughes, S. J.; Calomino, A. M.

2015-01-01

NASA is developing low ballistic coefficient technologies to support the Nations long-term goal of landing humans on Mars. Current entry, decent, and landing technologies are not practical for this class of payloads due to geometric constraints dictated by current and future launch vehicle fairing limitations. Hypersonic Inflatable Aerodynamic Decelerators (HIADs) are being developed to circumvent this limitation and are now considered a leading technology to enable landing of heavy payloads on Mars. At the beginning of 2014, a 6m diameter HIAD inflatable structure with an integrated flexible thermal protection system (TPS) was subjected to a static load test series to verify its structural performance under flight-relevant loads. The inflatable structure was constructed into a 60 degree sphere-cone configuration using nine inflatable torus segments composed of fiber-reinforced thin films. The inflatable tori were joined together using adhesives and high-strength textile woven structural straps. These straps help distribute the load throughout the inflatable structure. The 6m flexible TPS was constructed using multiple layers of high performance materials that are designed to protect the inflatable structure from heat loads that would be seen in flight during atmospheric entry. A custom test fixture was constructed to perform the static load test series. The fixture consisted of a round structural tub with enough height and width to allow for displacement of the HIAD test article as loads were applied. The bottom of the tub rim had an airtight seal with the floor. The rigid centerbody of the HIAD was mounted to a pedestal in the center of the structural tub. Using an impermeable membrane draped over the HIAD test article, an airtight seal was created with the top rim of the static load tub. This seal allowed partial vacuum to be pulled beneath the HIAD resulting in a uniform static pressure load applied to the outer surface. Using this technique, the test article was subjected to loads of up to 50,000lbs. During the test series an extensive amount of instrumentation was used to provide a rich data set, including deflected shape, structural strap loads, torus cord loads, inflation pressures, and applied static load. In this paper the 2014 6m HIAD static load test series will be discussed in detail, including the design of the 6m HIAD test article, the test setup, and test execution. Analysis results will be described supporting the conclusions that were drawn from the test series..

39. VIEW OF CHRYSLER WORKERS LOADING A SATURN IB BOOSTER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. VIEW OF CHRYSLER WORKERS LOADING A SATURN IB BOOSTER INTO THE EAST POSITION ON THE STATIC TEST TOWER. AS THE MAIN CONTRACTOR OF THE SATURN IB BOOSTER, CHRYSLER TOOK OVER OPERATIONS OF THE EAST POSITION OF THE STATIC TEST TOWER IN 1963. THAT SAME YEAR, THE WEST POSITION OF THE TEST TOWER WAS MODIFIED (AS SEEN IN THE PHOTO) FOR RESEARCH AND DEVELOPMENT TESTS OF THE SATURN V BOOSTER'S ENGINE, THE F-1. MARCH 1963, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Correlation of AH-1G airframe test data with a NASTRAN mathematical model

NASA Technical Reports Server (NTRS)

Cronkhite, J. D.; Berry, V. L.

1976-01-01

Test data was provided for evaluating a mathematical vibration model of the Bell AH-1G helicopter airframe. The math model was developed and analyzed using the NASTRAN structural analysis computer program. Data from static and dynamic tests were used for comparison with the math model. Static tests of the fuselage and tailboom were conducted to verify the stiffness representation of the NASTRAN model. Dynamic test data were obtained from shake tests of the airframe and were used to evaluate the NASTRAN model for representing the low frequency (below 30 Hz) vibration response of the airframe.

Meta-analysis of fish early life stage tests-Association of toxic ratios and acute-to-chronic ratios with modes of action.

PubMed

Scholz, Stefan; Schreiber, Rene; Armitage, James; Mayer, Philipp; Escher, Beate I; Lidzba, Annegret; Léonard, Marc; Altenburger, Rolf

2018-04-01

Fish early life stage (ELS) tests (Organisation for Economic Co-operation and Development test guideline 210) are widely conducted to estimate chronic fish toxicity. In these tests, fish are exposed from the embryonic to the juvenile life stages. To analyze whether certain modes of action are related to high toxic ratios (i.e., ratios between baseline toxicity and experimental effect) and/or acute-to-chronic ratios (ACRs) in the fish ELS test, effect concentrations (ECs) for 183 compounds were extracted from the US Environmental Protection Agency's ecotoxicity database. Analysis of ECs of narcotic compounds indicated that baseline toxicity could be observed in the fish ELS test at similar concentrations as in the acute fish toxicity test. All nonnarcotic modes of action were associated with higher toxic ratios, with median values ranging from 4 to 9.3 × 10 4 (uncoupling < reactivity < neuromuscular toxicity < methemoglobin formation < endocrine disruption < extracellular matrix formation inhibition). Four modes of action were also found to be associated with high ACRs: 1) lysyl oxidase inhibition leading to notochord distortion, 2) putative methemoglobin formation or hemolytic anemia, 3) endocrine disruption, and 4) compounds with neuromuscular toxicity. For the prediction of ECs in the fish ELS test with alternative test systems, endpoints targeted to the modes of action of compounds with enhanced toxic ratios or ACRs could be used to trigger fish ELS tests or even replace these tests. Environ Toxicol Chem 2018;37:955-969. © 2018 SETAC. © 2018 SETAC.

Biomimetic approaches for engineered organ chips and skin electronics for in vitro diagnostics

NASA Astrophysics Data System (ADS)

Suh, Kahp-Yang; Pang, Changhyun; Jang, Kyung-Jin; Kim, Hong Nam; Jiao, Alex; Hwang, Nathaniel S.; Kim, Min Sung; Kang, Do-Hyun; Kim, Deok-Ho

2012-10-01

Two kinds of biomimetic systems including engineered organ chip and flexible electronic sensor are presented. First, in vivo, renal tubular epithelial cells are exposed to luminal fluid shear stress (FSS) and a transepithelial osmotic gradient. In this study, we used a simple collecting-duct-on-a-chip to investigate the role of an altered luminal microenvironment in the translocation of aquaporin-2 (AQP2) and the reorganization of actin cytoskeleton (F-actin) in primary cultured inner medullary collecting duct (IMCD) cells of rat kidney. We demonstrate that several factors (i.e., luminal FSS, hormonal stimulation, transepithelial osmotic gradient) collectively exert a profound effect on the AQP2 trafficking in the collecting ducts, which is associated with actin cytoskeletal reorganization. Furthermore, with this kidney-mimicking chip, renal toxicity of cisplatin was tested under static and fluidic conditions, suggesting the physiological relevancy of fluidic environment compared to static culture. Second, we present a simple architecture for a flexible and highly sensitive strain sensor that enables the detection of pressure, shear and torsion. The device is based on two interlocked arrays of high-aspect-ratio Pt-coated polymeric nanofibres that are supported on thin polydimethylsiloxane layers. When different sensing stimuli are applied, the degree of interconnection and the electrical resistance of the sensor changes in a reversible, directional manner with specific, discernible strain-gauge factors. We show that the sensor can be used to monitor signals ranging from human heartbeats to the impact of a bouncing water droplet on a superhydrophobic surface.

Mycoremediation of congo red dye by filamentous fungi.

PubMed

Bhattacharya, Sourav; Das, Arijit; G, Mangai; K, Vignesh; J, Sangeetha

2011-10-01

Azo, anthroquinone and triphenylmethane dyes are the major classes of synthetic colourants, which are difficult to degrade and have received considerable attention. Congo red, a diazo dye, is considered as a xenobiotic compound, and is recalcitrant to biodegradative processes. Nevertheless, during the last few years it has been demonstrated that several fungi, under certain environmental conditions, are able to transfer azo dyes to non toxic products using laccases. The aim of this work was to study the factors influencing mycoremediation of Congo red. Several basidiomycetes and deuteromycetes species were tested for the decolourisation of Congo red (0.05 g/l) in a semi synthetic broth at static and shaking conditions. Poor decolourisation was observed when the dye acted as the sole source of nitrogen, whereas semi synthetic broth supplemented with fertilizer resulted in better decolourisation. Decolourisation of Congo red was checked in the presence of salts of heavy metals such as mercuric chloride, lead acetate and zinc sulphate. Decolourisation parameters such as temperature, pH, and rpm were optimized and the decolourisation obtained at optimized conditions varied between 29.25- 97.28% at static condition and 82.1- 100% at shaking condition. Sodium dodecyl sulphate polyacrylamide gel electrophoretic analysis revealed bands with molecular weights ranging between 66.5 to 71 kDa, a characteristic of the fungal laccases. High efficiency decolourisation of Congo red makes these fungal forms a promising choice in biological treatment of waste water containing Congo red.

A new biological test of water toxicity-yeast Saccharomyces cerevisiae conductometric test.

PubMed

Dolezalova, Jaroslava; Rumlova, Lubomira

2014-11-01

This new biological test of water toxicity is based on monitoring of specific conductivity changes of yeast Saccharomyces cerevisiae suspension as a result of yeast fermentation activity inhibition in toxic conditions. The test was verified on ten substances with various mechanisms of toxic effect and the results were compared with two standard toxicity tests based on Daphnia magna mobility inhibition (EN ISO 6341) and Vibrio fischeri bioluminescence inhibition (EN ISO 11348-2) and with the results of the S. cerevisiae lethal test (Rumlova and Dolezalova, 2012). The new biological test - S. cerevisiae conductometric test - is an express method developed primarily for field conditions. It is applicable in case of need of immediate information about water toxicity. Fast completion is an advantage of this test (time necessary for test completion is about 60min), the test is simple and the test organism - dried instant yeast - belongs among its biggest advantages because of its long-term storage life and broad availability. Copyright © 2014 Elsevier B.V. All rights reserved.

Sediment quality assessment studies of Tampa bay, Florida

USGS Publications Warehouse

Carr, Scott R.; Chapman, Duane C.; Long, Edward R.; Windom, Herbert L.; Thursby, Glen; Sloane, Gail M.; Wolfe, Douglas A.

1996-01-01

A survey of the toxicity of sediments throughout the Tampa Bay estuary was performed as part of the National Oceanic and Atmospheric Administration's National Status and Trends Program. The objectives of the survey were to determine the spatial extent and severity of toxicity and to identify relationships between chemical contamination and toxicity. Three independent toxicity tests were performed: a 10-d amphipod survival test of the whole sediments with Ampelisca abdita, a sea urchin fertilization test of sediment pore water with Arbacia punctulata, and a 5-min Microtox® bioluminescence test with solvent extracts of the sediments. Seventy-three percent of the 165 undiluted sediment pore-water samples were significantly toxic relative to reference samples with the sea urchin fertilization test. In contrast, only 2% of the 165 samples were significantly toxic in the amphipod tests. The causes of toxicity were not determined. However, concentrations of numerous trace metals, pesticides, polychlorinated biphenyl (PCB) congeners, polycyclic aromatic hydrocarbons (PAHs), and ammonia were highly correlated with pore-water toxicity. Concentrations of many substances, especially total dichlorodiphenyltrichloroethanes (DDTs), endrin, total PCBs, certain PAHs, lead, and zinc, occurred at concentrations in the toxic samples that equaled or exceeded concentrations that have been previously associated with sediment toxicity.

Aquatic information and retrieval (AQUIRE) database system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunter, R.; Niemi, G.; Pilli, A.

The AQUIRE database system is one of the foremost international resources for finding aquatic toxicity information. Information in the system is organized around the concept of an 'aquatic toxicity test.' A toxicity test record contains information about the chemical, species, endpoint, endpoint concentrations, and test conditions under which the toxicity test was conducted. For the past 10 years aquatic literature has been reviewed and entered into the system. Currently, the AQUIRE database system contains data on more than 2,400 species, 160 endpoints, 5,000 chemicals, 6,000 references, and 104,000 toxicity tests.

Constitutive equation of friction based on the subloading-surface concept

PubMed Central

Ueno, Masami; Kuwayama, Takuya; Suzuki, Noriyuki; Yonemura, Shigeru; Yoshikawa, Nobuo

2016-01-01

The subloading-friction model is capable of describing static friction, the smooth transition from static to kinetic friction and the recovery to static friction after sliding stops or sliding velocity decreases. This causes a negative rate sensitivity (i.e. a decrease in friction resistance with increasing sliding velocity). A generalized subloading-friction model is formulated in this article by incorporating the concept of overstress for viscoplastic sliding velocity into the subloading-friction model to describe not only negative rate sensitivity but also positive rate sensitivity (i.e. an increase in friction resistance with increasing sliding velocity) at a general sliding velocity ranging from quasi-static to impact sliding. The validity of the model is verified by numerical experiments and comparisons with test data obtained from friction tests using a lubricated steel specimen. PMID:27493570

Comparison of Static and Dynamic Balance in Female Collegiate Soccer, Basketball, and Gymnastics Athletes

PubMed Central

Bressel, Eadric; Yonker, Joshua C; Kras, John; Heath, Edward M

2007-01-01

Context: How athletes from different sports perform on balance tests is not well understood. When prescribing balance exercises to athletes in different sports, it may be important to recognize performance variations. Objective: To compare static and dynamic balance among collegiate athletes competing or training in soccer, basketball, and gymnastics. Design: A quasi-experimental, between-groups design. Independent variables included limb (dominant and nondominant) and sport played. Setting: A university athletic training facility. Patients or Other Participants: Thirty-four female volunteers who competed in National Collegiate Athletic Association Division I soccer (n = 11), basketball (n = 11), or gymnastics (n = 12). Intervention(s): To assess static balance, participants performed 3 stance variations (double leg, single leg, and tandem leg) on 2 surfaces (stiff and compliant). For assessment of dynamic balance, participants performed multidirectional maximal single-leg reaches from a unilateral base of support. Main Outcome Measure(s): Errors from the Balance Error Scoring System and normalized leg reach distances from the Star Excursion Balance Test were used to assess static and dynamic balance, respectively. Results: Balance Error Scoring System error scores for the gymnastics group were 55% lower than for the basketball group (P = .01), and Star Excursion Balance Test scores were 7% higher in the soccer group than the basketball group (P = .04). Conclusions: Gymnasts and soccer players did not differ in terms of static and dynamic balance. In contrast, basketball players displayed inferior static balance compared with gymnasts and inferior dynamic balance compared with soccer players. PMID:17597942

A dynamic approach for the impact of a toxic gas dispersion hazard considering human behaviour and dispersion modelling.

PubMed

Lovreglio, Ruggiero; Ronchi, Enrico; Maragkos, Georgios; Beji, Tarek; Merci, Bart

2016-11-15

The release of toxic gases due to natural/industrial accidents or terrorist attacks in populated areas can have tragic consequences. To prevent and evaluate the effects of these disasters different approaches and modelling tools have been introduced in the literature. These instruments are valuable tools for risk managers doing risk assessment of threatened areas. Despite the significant improvements in hazard assessment in case of toxic gas dispersion, these analyses do not generally include the impact of human behaviour and people movement during emergencies. This work aims at providing an approach which considers both modelling of gas dispersion and evacuation movement in order to improve the accuracy of risk assessment for disasters involving toxic gases. The approach is applied to a hypothetical scenario including a ship releasing Nitrogen dioxide (NO2) on a crowd attending a music festival. The difference between the results obtained with existing static methods (people do not move) and a dynamic approach (people move away from the danger) which considers people movement with different degrees of sophistication (either a simple linear path or more complex behavioural modelling) is discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

A test strategy for the assessment of additive attributed toxicity of tobacco products.

PubMed

Kienhuis, Anne S; Staal, Yvonne C M; Soeteman-Hernández, Lya G; van de Nobelen, Suzanne; Talhout, Reinskje

2016-08-01

The new EU Tobacco Product Directive (TPD) prohibits tobacco products containing additives that are toxic in unburnt form or that increase overall toxicity of the product. This paper proposes a strategy to assess additive attributed toxicity in the context of the TPD. Literature was searched on toxicity testing strategies for regulatory purposes from tobacco industry and governmental institutes. Although mainly traditional in vivo testing strategies have been applied to assess toxicity of unburnt additives and increases in overall toxicity of tobacco products due to additives, in vitro tests combined with toxicogenomics and validated using biomarkers of exposure and disease are most promising in this respect. As such, tests are needed that are sensitive enough to assess additive attributed toxicity above the overall toxicity of tobacco products, which can associate assay outcomes to human risk and exposure. In conclusion, new, sensitive in vitro assays are needed to conclude whether comparable testing allows for assessment of small changes in overall toxicity attributed to additives. A more pragmatic approach for implementation on a short-term is mandated lowering of toxic emission components. Combined with risk assessment, this approach allows assessment of effectiveness of harm reduction strategies, including banning or reducing of additives. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exposure Science for Chemical Prioritization and Toxicity Testing

EPA Science Inventory

Currently, a significant research effort is underway to apply new technologies to screen and prioritize chemicals for toxicity testing as well as to improve understanding of toxicity pathways (Dix et al. 2007, Toxicol Sci; NRC, 2007, Toxicity Testing in the 21st Century; Collins ...

A ten year summary of concurrent ambient water column and sediment toxicity tests in the Chesapeake Bay watershed: 1990-1999.

PubMed

Hall, Lenwood W; Anderson, Ronald D; Alden, Raymond W

2002-06-01

The goal of this study was to identify the relative toxicity of ambient areas in the Chesapeake Bay watershed by using a suite of concurrent water column and sediment toxicity tests at seventy-five ambient stations in 20 Chesapeake Bay rivers from 1990 through 1999. Spatial and temporal variability was examined at selected locations throughout the 10 yr study. Inorganic and organic contaminants were evaluated in ambient water and sediment concurrently with water column and sediment tests to assess possible causes of toxicity although absolute causality can not be established. Multivariate statistical analysis was used to develop a multiple endpoint toxicity index (TOX-INDEX) at each station for both water column and sediment toxicity data. Water column tests from the 10 yr testing period showed that 49% of the time, some degree of toxicity was reported. The most toxic sites based on water column results were located in urbanized areas such as the Anacostia River, Elizabeth River and the Middle River. Water quality criteria for copper, lead, mercury, nickel and zinc were exceeded at one or more of these sites. Water column toxicity was also reported in localized areas of the South and Chester Rivers. Both spatial and temporal variability was reported from the suite of water column toxicity tests. Some degree of sediment toxicity was reported from 62% of the tests conducted during the ten year period. The Elizabeth River and Baltimore Harbor stations were reported as the most toxic areas based on sediment results. Sediment toxicity guidelines were exceeded for one or more of the following metals at these two locations: arsenic, cadmium, chromium, copper, lead, nickel and zinc. At the Elizabeth River stations nine of sixteen semi-volatile organics and two of seven pesticides measured exceeded the ER-M values in 1990. Ambient sediment toxicity tests in the Elizabeth River in 1996 showed reduced toxicity. Various semi-volatile organics exceeded the ER-M values at a number of Baltimore Harbor sites; pyrene and dibenzo(a,h)anthracene were particularly high at one of the stations (Northwest Harbor). Localized sediment toxicity was also reported in the Chester, James, Magothy, Rappahannock, and Potomac Rivers but the link with contaminants was not determined. Both spatial and temporal variability was less for sediment toxicity data when compared with water column toxicity data. A comparison of water column and sediment toxicity data for the various stations over the 10 yr study showed that approximately half the time agreement occurred (either both suite of tests showed toxicity or neither suite of tests showed toxicity).

MR 201104: Evaluation of Discrimination Technologies and Classification Results and MR 201157: Demonstration of MetalMapper Static Data Acquisition and Data Analysis

DTIC Science & Technology

2016-09-23

Acquisition and Data Analysis). EMI sensors, MetalMapper, man-portable Time-domain Electromagnetic Multi-sensor Towed Array Detection System (TEMTADS...California Department of Toxic Substances Control EM61 EM61-MK2 EMI electromagnetic induction ESTCP Environmental Security Technology Certification...SOP Standard Operating Procedure v TEMTADS Time-domain Electromagnetic Multi-sensor Towed Array Detection System man-portable 2x2 TOI target(s

Joint toxic effects of triazophos and imidacloprid on zebrafish (Danio rerio).

PubMed

Wu, Shenggan; Li, Xinfang; Liu, Xinju; Yang, Guiling; An, Xuehua; Wang, Qiang; Wang, Yanhua

2018-04-01

Pesticide contamination is more often found as a mixture of different pesticides in water bodies rather than individual compounds. However, regulatory risk evaluation is mostly based on the effects of individual pesticides. In the present study, we aimed to investigate the individual and joint toxicities of triazophos (TRI) and imidacloprid (IMI) to the zebrafish (Danio rerio) using acute indices and various sublethal endpoints. Results from 96-h semi-static test indicated that the LC 50 values of TRI to D. rerio at multiple life stages (embryonic, larval, juvenile and adult stages) ranged from 0.49 (0.36-0.71) to 4.99 (2.06-6.81) mg a.i. L -1 , which were higher than those of IMI ranging from 26.39 (19.04-38.01) to 128.9 (68.47-173.6) mg a.i. L -1 . Pesticide mixtures of TRI and IMI displayed synergistic response to zebrafish embryos. Activities of carboxylesterase (CarE) and catalase (CAT) were significantly changed in most of the individual and joint exposures of pesticides compared with the control group. The expressions of 26 genes related to oxidative stress, cellular apoptosis, immune system, hypothalamic-pituitary-thyroid and hypothalamic-pituitary-gonadal axis at the mRNA level revealed that zebrafish embryos were affected by the individual or joint pesticides, and greater changes in the expressions of six genes (Mn-sod, CXCL-CIC, Dio1, Dio2, tsh and vtg1) were observed when exposed to joint pesticides compared with their individual pesticides. Taken together, the synergistic effects indicated that it was highly important to incorporate joint toxicity studies, especially at low concentrations, when assessing the risk of pesticides. Copyright © 2018 Elsevier Ltd. All rights reserved.

Applying theoretical premises of binary toxicity mathematical modeling to combined impacts of chemical plus physical agents (A case study of moderate subchronic exposures to fluoride and static magnetic field).

PubMed

Katsnelson, B A; Tsepilov, N A; Panov, V G; Sutunkova, M P; Varaksin, A N; Gurvich, V B; Minigalieva, I A; Valamina, I E; Makeyev, O H; Meshtcheryakova, E Y

2016-09-01

Sodium fluoride solution was injected i.p. to rats at a dose equivalent to 0.1 LD50 three times a week up to 18 injections. Two thirds of these rats and of the sham-injected ones were exposed to the whole body impact of a 25 mT static magnetic field for 2 or 4 h a day, 5 times a week. For mathematical analysis of the effects they produced in combination, we used a response surface model. This analysis demonstrated that (like in combined toxicity) the combined adverse action of a chemical plus a physical agent was characterized by a diversity of types depending not only on particular effects these types were assessed for but on their level as well. From this point of view, the indices for which at least one statistically significant effect was observed could be classified as identifying (1) single-factor action; (2) additivity; (3) synergism; (4) antagonism (both subadditive unidirectional action and all variants of contradirectional action). Although the classes (2) and (3) taken together encompass a smaller part of the indices, the biological importance of some of them renders the combination of agents studied as posing a higher health risk than that associated with each them acting alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Interpretation and use of routine pulmonary function tests: Spirometry, static lung volumes, lung diffusion, arterial blood gas, methacholine challenge test and 6-minute walk test].

PubMed

Bokov, P; Delclaux, C

2016-02-01

Resting pulmonary function tests (PFT) include the assessment of ventilatory capacity: spirometry (forced expiratory flows and mobilisable volumes) and static volume assessment, notably using body plethysmography. Spirometry allows the potential definition of obstructive defect, while static volume assessment allows the potential definition of restrictive defect (decrease in total lung capacity) and thoracic hyperinflation (increase in static volumes). It must be kept in mind that this evaluation is incomplete and that an assessment of ventilatory demand is often warranted, especially when facing dyspnoea: evaluation of arterial blood gas (searching for respiratory insufficiency) and measurement of the transfer coefficient of the lung, allowing with the measurement of alveolar volume to calculate the diffusing capacity of the lung for CO (DLCO: assessment of alveolar-capillary wall and capillary blood volume). All these pulmonary function tests have been the subject of an Americano-European Task force (standardisation of lung function testing) published in 2005, and translated in French in 2007. Interpretative strategies for lung function tests have been recommended, which define abnormal lung function tests using the 5th and 95th percentiles of predicted values (lower and upper limits of normal values). Thus, these recommendations need to be implemented in all pulmonary function test units. A methacholine challenge test will only be performed in the presence of an intermediate pre-test probability for asthma (diagnostic uncertainty), which is an infrequent setting. The most convenient exertional test is the 6-minute walk test that allows the assessment of walking performance, the search for arterial desaturation and the quantification of dyspnoea complaint. Copyright © 2015 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.

Prediction of acid mine drainage generation potential of various lithologies using static tests: Etili coal mine (NW Turkey) as a case study.

PubMed

Yucel, Deniz Sanliyuksel; Baba, Alper

2016-08-01

The Etili neighborhood in Can County (northwestern Turkey) has large reserves of coal and has been the site of many small- to medium-scale mining operations since the 1980s. Some of these have ceased working while others continue to operate. Once activities cease, the mining facilities and fields are usually abandoned without rehabilitation. The most significant environmental problem is acid mine drainage (AMD). This study was carried out to determine the acid generation potential of various lithological units in the Etili coal mine using static test methods. Seventeen samples were selected from areas with high acidic water concentrations: from different alteration zones belonging to volcanic rocks, from sedimentary rocks, and from coals and mine wastes. Static tests (paste pH, standard acid-base accounting, and net acid generation tests) were performed on these samples. The consistency of the static test results showed that oxidation of sulfide minerals, especially pyrite-which is widely found not only in the alteration zones of volcanic rocks but also in the coals and mine wastes-is the main factor controlling the generation of AMD in this mine. Lack of carbonate minerals in the region also increases the occurrence of AMD.

Behavior of plywood and fiberglass steel composite tube structures subjected to impact loading

NASA Astrophysics Data System (ADS)

Armaghani, Seyamend Bilind

Paratransit buses are custom built as the major vehicle manufacturer produces the custom built passenger cage installed on the chassis for the Paratransit bus. In order for these Paratransit bus members to be sufficient, they have to be evaluated for crashworthiness and energy absorption. This has prompted Florida Department of Transportation (FDOT) to fund research for the safety evaluation of Paratransit busses consisting of crash and safety analysis. There has been a large body of research done on steel subjected to static loads, but more research is needed for steel applied under dynamic loading and high speeds in order to improve crashworthiness in events such as rollovers and side impacts. Bare steel Hollow Structural Section (HSS) tubing are used a lot as structural members of Paratransit buses because of their lightness and progressive buckling under loading. The research will be conducted on quantifying the tubing's behavior under bending by conducting static three point bending and impact loading tests. In addition to the bare tubing, plywood and fiberglass composites are investigated because they are both strong and lightweight and their behavior under dynamic loading hasn't been quantified. As a result, the main purpose of this research is to quantify the differences between the dynamic and static behavior of plywood steel composite and fiberglass steel composite tubing and compare these findings with those of bare steel tubing. The differences will be quantified using detailed and thorough experiments that will examine the composites behavior under both static and dynamic loading. These tests will determine if there are any advantages of using the composite materials and thus allow for recommendations to be made to the FDOT with the goal of improving the safety of Paratransit busses. Tensile tests were conducted to determine the material properties of the tested specimens. Before the static and dynamic experiments are run to investigate the differences between static and dynamic behavior, Preliminary three point bending testing was conducted to determine the parameters for the final experiments. Static bending testing was conducted on the bare, plywood composite, and fiberglass composite steel tubing. The point of these experiments was to produce a Moment vs. Rotation plot to determine the specimens' maximum moments and their associated rotation, as that is when the steel buckles and fails. The dynamic three point bending experiments were conducted using the impact loading apparatus and had the same purpose as the static experiments. For both static and dynamic experiments, the performances of the different types of specimens were compared based upon their Moment vs. Rotation plots. This will determine the effect that the composite has on the rotation and maximum moment at which the tubing fails. After conducting these experiments, amplification factors were established for each specimen by comparing the maximum moment and their associated rotation between static and dynamic testing. lambda was calculated to quantify the ratio between the static and dynamic maximum moments. beta was used to quantify the ratio between the rotation needed to produce the maximum moment between static and dynamic events. A small amplification factor denotes that material performs well under impact loading and the material doesn't experience dramatic change in behavior during dynamic events. Amplification factors were compared between the bare, plywood, and fiberglass composite steel tubing in order to evaluate the performance of the composites. After comparing the amplification factors of the different types of tubing, recommendations can be made. Fiberglass and plywood composite were shown to be valuable because it decreased the effect of dynamic forces as beta was reduced by a factor of 2 in comparison to bare tubing. Based upon the amplification factors, it was recommended to use 14 gauge fiberglass composite tubing as Paratransit bus structural members because it was affected the least by dynamic loading.

Comparison of User Performance with Interactive and Static 3d Visualization - Pilot Study

NASA Astrophysics Data System (ADS)

Herman, L.; Stachoň, Z.

2016-06-01

Interactive 3D visualizations of spatial data are currently available and popular through various applications such as Google Earth, ArcScene, etc. Several scientific studies have focused on user performance with 3D visualization, but static perspective views are used as stimuli in most of the studies. The main objective of this paper is to try to identify potential differences in user performance with static perspective views and interactive visualizations. This research is an exploratory study. An experiment was designed as a between-subject study and a customized testing tool based on open web technologies was used for the experiment. The testing set consists of an initial questionnaire, a training task and four experimental tasks. Selection of the highest point and determination of visibility from the top of a mountain were used as the experimental tasks. Speed and accuracy of each task performance of participants were recorded. The movement and actions in the virtual environment were also recorded within the interactive variant. The results show that participants deal with the tasks faster when using static visualization. The average error rate was also higher in the static variant. The findings from this pilot study will be used for further testing, especially for formulating of hypotheses and designing of subsequent experiments.

Calibration of a pitot-static rake

NASA Technical Reports Server (NTRS)

Stump, H. P.

1977-01-01

A five-element pitot-static rake was tested to confirm its accuracy and determine its suitability for use at Langley during low-speed tunnel calibration primarily at full-scale tunnel. The rake was tested at one airspeed of 74 miles per hour (33 meters per second) and at pitch and yaw angles of 0 to + or - 20 degrees in 4 deg increments.

Parachute Aerodynamics From Video Data

NASA Technical Reports Server (NTRS)

Schoenenberger, Mark; Queen, Eric M.; Cruz, Juan R.

2005-01-01

A new data analysis technique for the identification of static and dynamic aerodynamic stability coefficients from wind tunnel test video data is presented. This new technique was applied to video data obtained during a parachute wind tunnel test program conducted in support of the Mars Exploration Rover Mission. Total angle-of-attack data obtained from video images were used to determine the static pitching moment curve of the parachute. During the original wind tunnel test program the static pitching moment curve had been determined by forcing the parachute to a specific total angle-of -attack and measuring the forces generated. It is shown with the new technique that this parachute, when free to rotate, trims at an angle-of-attack two degrees lower than was measured during the forced-angle tests. An attempt was also made to extract pitch damping information from the video data. Results suggest that the parachute is dynamically unstable at the static trim point and tends to become dynamically stable away from the trim point. These trends are in agreement with limit-cycle-like behavior observed in the video. However, the chaotic motion of the parachute produced results with large uncertainty bands.

Impact Behavior of Composite Fan Blade Leading Edge Subcomponent with Thermoplastic Polyurethane Interleave

NASA Technical Reports Server (NTRS)

Miller, Sandi G.; Roberts, Gary D.; Kohlman, Lee W.; Heimann, Paula J.; Pereira, J. Michael; Ruggeri, Charles R.; Martin, Richard E.; McCorkle, Linda S.

2015-01-01

Impact damage tolerance and damage resistance is a critical metric for application of polymer matrix composites where failure caused by impact damage could compromise structural performance and safety. As a result, several materials and/or design approaches to improve impact damage tolerance have been investigated over the past several decades. Many composite toughening methodologies impart a trade-off between increased fracture toughness and compromised in-plane strength and modulus. In large part, mechanical tests to evaluate composite damage tolerance include static methods such as Mode I, Mode II, and mixed mode failures. However, ballistic impact damage resistance does not always correlate with static properties. The intent of this paper is to evaluate the influence of a thermoplastic polyurethane veil interleave on the static and dynamic performance of composite test articles. Static coupon tests included tension, compression, double cantilever beam, and end notch flexure. Measurement of the resistance to ballistic impact damage were made to evaluate the composites response to high speed impact. The interlayer material showed a decrease of in-plane performance with only a moderate improvement to Mode I and Mode II fracture toughness. However, significant benefit to impact damage tolerance was observed through ballistic tests.

The Contact Ageing Effect on Fretting Damage of an Electro-Deposited Coating against an AISI52100 Steel Ball

PubMed Central

Kim, Kyungmok; Ko, Joon Soo

2016-01-01

This article investigates the effect of contact ageing on fretting damage of an epoxy-based cathodic electro-deposited coating for use on automotive seat slide tracks (made of cold-rolled high strength steel). Static normal load was induced at the contact between the coating and an AISI52100 ball for a certain duration. It was identified that plastically deformed contact area increased logarithmically as a function of time when the contact was under static normal load. Fretting tests after various durations of static contact were conducted using a ball-on-flat plate apparatus. All fretting tests were halted when the friction coefficient reached a critical value of 0.5, indicating complete coating failure. The total number of fretting cycles to the critical friction coefficient was found to vary with the duration of static contact before fretting. It was identified that the number of cycles to the critical friction coefficient decreased with the increased duration of static contact. Meanwhile, the friction coefficient at steady-state sliding was not greatly affected by the duration of static contact before fretting. Finally, the relation between coating thickness after indentation creep and the number of cycles to the critical friction coefficient was found to be linear. Obtained results show that the duration of static contact before fretting has an influence on the fretting lifetime of an electro-deposited coating. PMID:28773873

The Contact Ageing Effect on Fretting Damage of an Electro-Deposited Coating against an AISI52100 Steel Ball.

PubMed

Kim, Kyungmok; Ko, Joon Soo

2016-09-03

This article investigates the effect of contact ageing on fretting damage of an epoxy-based cathodic electro-deposited coating for use on automotive seat slide tracks (made of cold-rolled high strength steel). Static normal load was induced at the contact between the coating and an AISI52100 ball for a certain duration. It was identified that plastically deformed contact area increased logarithmically as a function of time when the contact was under static normal load. Fretting tests after various durations of static contact were conducted using a ball-on-flat plate apparatus. All fretting tests were halted when the friction coefficient reached a critical value of 0.5, indicating complete coating failure. The total number of fretting cycles to the critical friction coefficient was found to vary with the duration of static contact before fretting. It was identified that the number of cycles to the critical friction coefficient decreased with the increased duration of static contact. Meanwhile, the friction coefficient at steady-state sliding was not greatly affected by the duration of static contact before fretting. Finally, the relation between coating thickness after indentation creep and the number of cycles to the critical friction coefficient was found to be linear. Obtained results show that the duration of static contact before fretting has an influence on the fretting lifetime of an electro-deposited coating.

Dynamic and static fatigue behavior of sintered silicon nitrides

NASA Technical Reports Server (NTRS)

Chang, J.; Khandelwal, P.; Heitman, P. W.

1987-01-01

The dynamic and static fatigue behavior of Kyocera SN220M sintered silicon nitride at 1000 C was studied. Fractographic analysis of the material failing in dynamic fatigue revealed the presence of slow crack growth (SCG) at stressing rates below 41 MPa/min. Under conditions of static fatigue this material also displayed SCG at stresses below 345 MPa. SCG appears to be controlled by microcracking of the grain boundaries. The crack velocity exponent (n) determined from both dynamic and static fatigue tests ranged from 11 to 16.

Water Ingestion into Axial Flow Compressors. Part III. Experimental Results and Discussion

DTIC Science & Technology

1981-10-01

total pressure, static pressure, and temperature at both compressor inlet and outlet. A United Sensor model PDC-12-G-l0-KL pitot-static pressure probe...Test Compressor inlet and outlet temperatures during water injection tests: United Sensor and Control Corp. type TK-8-CiA-36’-F Aspirate...ured utilizing standard aspirated thermocouples, namely an United Sensor and Control Corp. type TK-8-C/A-36-F. The Test Compressor out- let

Mechanical strength of an ITER coil insulation system under static and dynamic load after reactor irradiation

NASA Astrophysics Data System (ADS)

Bittner-Rohrhofer, K.; Humer, K.; Weber, H. W.; Hamada, K.; Sugimoto, M.; Okuno, K.

2002-12-01

The insulation system proposed by the Japanese Home Team for the ITER Toroidal Field coil (TF coil) is a T-glass-fiber/Kapton reinforced epoxy prepreg system. In order to assess the material performance under the actual operating conditions of the coils, the insulation system was irradiated in the TRIGA reactor (Vienna) to a fast neutron fluence of 2×10 22 m -2 ( E>0.1 MeV). After measurements of swelling, all mechanical tests were carried out at 77 K. Tensile and short-beam-shear (SBS) tests were performed under static loading conditions. In addition, tension-tension fatigue experiments up to about 10 6 cycles were made. The laminate swells in the through-thickness direction by 0.86% at the highest dose level. The fatigue tests as well as the static tests do not show significant influences of the irradiation on the mechanical behavior of this composite.

Static Fatigue of a Siliconized Silicon Carbide

DTIC Science & Technology

1987-03-01

flexitral stress rupture and stepped temperature stress rupture (STSR) testing were performed to assess the static fatigue and creep resistances. Isothermal... stress rupture experiments were performed at 1200 0C in air for com- parison to previous results. - 10 STSR experiments 15 were under deadweight...temperature and stress levels that static fatigue and creep processes are active. The applied stresses were computed on the basis of the elastic

Patellofemoral Pressure Changes After Static and Dynamic Medial Patellofemoral Ligament Reconstructions.

PubMed

Rood, Akkie; Hannink, Gerjon; Lenting, Anke; Groenen, Karlijn; Koëter, Sander; Verdonschot, Nico; van Kampen, Albert

2015-10-01

Reconstructing the medial patellofemoral ligament (MPFL) has become a key procedure for stabilizing the patella. Different techniques to reconstruct the MPFL have been described: static techniques in which the graft is fixed rigidly to the bone or dynamic techniques with soft tissue fixation. Static MPFL reconstruction is most commonly used. However, dynamic reconstruction deforms more easily and presumably functions more like the native MPFL. The aim of the study was to evaluate the effect of the different MPFL fixation techniques on patellofemoral pressures compared with the native situation. The hypothesis was that dynamic reconstruction would result in patellofemoral pressures closer to those generated in an intact knee. Controlled laboratory study. Seven fresh-frozen knee specimens were tested in an in vitro knee joint loading apparatus. Tekscan pressure-sensitive films fixed to the retropatellar cartilage measured mean patellofemoral and peak pressures, contact area, and location of the center of force (COF) at fixed flexion angles from 0° to 110°. Four different conditions were tested: intact, dynamic, partial dynamic, and static MPFL reconstruction. Data were analyzed using linear mixed models. Static MPFL reconstruction resulted in higher peak and mean pressures from 60° to 110° of flexion (P < .001). There were no differences in pressure between the 2 different dynamic reconstructions and the intact situation (P > .05). The COF in the static reconstruction group moved more medially on the patella from 50° to 110° of flexion compared with the other conditions. The contact area showed no significant differences between the test conditions. After static MPFL reconstruction, the patellofemoral pressures in flexion angles from 60° to 110° were 3 to 5 times higher than those in the intact situation. The pressures after dynamic MPFL reconstruction were similar as compared with those in the intact situation, and therefore, dynamic MPFL reconstruction could be a safer option than static reconstruction for stabilizing the patella. This study showed that static MPFL reconstruction results in higher patellofemoral pressures and thus enhances the chance of osteoarthritis in the long term, while dynamic reconstruction results in more normal pressures. © 2015 The Author(s).

Static internal performance of single-expansion-ramp nozzles with various combinations of internal geometric parameters

NASA Technical Reports Server (NTRS)

Re, R. J.; Leavitt, L. D.

1984-01-01

The effects of five geometric design parameters on the internal performance of single-expansion-ramp nozzles were investigated at nozzle pressure ratios up to 10 in the static-test facility of the Langley 16-Foot Transonic Tunnel. The geometric variables on the expansion-ramp surface of the upper flap consisted of ramp chordal angle, ramp length, and initial ramp angle. On the lower flap, the geometric variables consisted of flap angle and flap length. Both internal performance and static-pressure distributions on the centerlines of the upper and lower flaps were obtained for all 43 nozzle configurations tested.

Bioassay selection, experimental design and quality control/assurance for use in effluent assessment and control.

PubMed

Johnson, Ian; Hutchings, Matt; Benstead, Rachel; Thain, John; Whitehouse, Paul

2004-07-01

In the UK Direct Toxicity Assessment Programme, carried out in 1998-2000, a series of internationally recognised short-term toxicity test methods for algae, invertebrates and fishes, and rapid methods (ECLOX and Microtox) were used extensively. Abbreviated versions of conventional tests (algal growth inhibition tests, Daphnia magna immobilisation test and the oyster embryo-larval development test) were valuable for toxicity screening of effluent discharges and the identification of causes and sources of toxicity. Rapid methods based on chemiluminescence and bioluminescence were not generally useful in this programme, but may have a role where the rapid test has been shown to be an acceptable surrogate for a standardised test method. A range of quality assurance and control measures were identified. Requirements for quality control/assurance are most stringent when deriving data for characterising the toxic hazards of effluents and monitoring compliance against a toxicity reduction target. Lower quality control/assurance requirements can be applied to discharge screening and the identification of causes and sources of toxicity.

Analytical modeling of transport aircraft crash scenarios to obtain floor pulses

NASA Technical Reports Server (NTRS)

Wittlin, G.; Lackey, D.

1983-01-01

The KRAS program was used to analyze transport aircraft candidate crash scenarios. Aircraft floor pulses and seat/occupant responses are presented. Results show that: (1) longitudinal only pulses can be represented by equivalent step inputs and/or static requirements; (2) the L1649 crash test floor longitudinal pulse for the aft direction (forward inertia) is less than 9g static or an equivalent 5g pulse; aft inertia accelerations are extremely small ((ch76) 3g) for representative crash scenarios; (3) a viable procedure to relate crash scenario floor pulses to standard laboratory dynamic and static test data using state of the art analysis and test procedures was demonstrated; and (4) floor pulse magnitudes are expected to be lower for wide body aircraft than for smaller narrow body aircraft.

EPA’s ToxCast Program for Predicting Toxicity and Prioritizing Chemicals for Further Screening and Testing

EPA Science Inventory

Testing of environmental and industrial chemicals for toxicity potential is a daunting task because of the wide range of possible toxicity mechanisms. Although animal testing is one means of achieving broad toxicity coverage, evaluation of large numbers of chemicals is challengin...

TEST (Toxicity Estimation Software Tool) Ver 4.1

EPA Science Inventory

The Toxicity Estimation Software Tool (T.E.S.T.) has been developed to allow users to easily estimate toxicity and physical properties using a variety of QSAR methodologies. T.E.S.T allows a user to estimate toxicity without requiring any external programs. Users can input a chem...

Static and dynamic fatigue behavior of topology designed and conventional 3D printed bioresorbable PCL cervical interbody fusion devices.

PubMed

Knutsen, Ashleen R; Borkowski, Sean L; Ebramzadeh, Edward; Flanagan, Colleen L; Hollister, Scott J; Sangiorgio, Sophia N

2015-09-01

Recently, as an alternative to metal spinal fusion cages, 3D printed bioresorbable materials have been explored; however, the static and fatigue properties of these novel cages are not well known. Unfortunately, current ASTM testing standards used to determine these properties were designed prior to the advent of bioresorbable materials for cages. Therefore, the applicability of these standards for bioresorbable materials is unknown. In this study, an image-based topology and a conventional 3D printed bioresorbable poly(ε)-caprolactone (PCL) cervical cage design were tested in compression, compression-shear, and torsion, to establish their static and fatigue properties. Difficulties were in fact identified in establishing failure criteria and in particular determining compressive failure load. Given these limitations, under static loads, both designs withstood loads of over 650 N in compression, 395 N in compression-shear, and 0.25 Nm in torsion, prior to yielding. Under dynamic testing, both designs withstood 5 million (5M) cycles of compression at 125% of their respective yield forces. Geometry significantly affected both the static and fatigue properties of the cages. The measured compressive yield loads fall within the reported physiological ranges; consequently, these PCL bioresorbable cages would likely require supplemental fixation. Most importantly, supplemental testing methods may be necessary beyond the current ASTM standards, to provide more accurate and reliable results, ultimately improving preclinical evaluation of these devices. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigation of Gearbox Vibration Transmission Paths on Gear Condition Indicator Performance

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Islam, AKM Anwarul; Feldman, Jason; Larsen, Chris

2013-01-01

Helicopter health monitoring systems use vibration signatures generated from damaged components to identify transmission faults. For damaged gears, these signatures relate to changes in dynamics due to the meshing of the damaged tooth. These signatures, referred to as condition indicators (CI), can perform differently when measured on different systems, such as a component test rig, or a full-scale transmission test stand, or an aircraft. These differences can result from dissimilarities in systems design and environment under dynamic operating conditions. The static structure can also filter the response between the vibration source and the accelerometer, when the accelerometer is installed on the housing. To assess the utility of static vibration transfer paths for predicting gear CI performance, measurements were taken on the NASA Glenn Spiral Bevel Gear Fatigue Test Rig. The vibration measurements were taken to determine the effect of torque, accelerometer location and gearbox design on accelerometer response. Measurements were taken at the housing and compared while impacting the gear set near mesh. These impacts were made at gear mesh to simulate gear meshing dynamics. Data measured on a helicopter gearbox installed in a static fixture were also compared to the test rig. The behavior of the structure under static conditions was also compared to CI values calculated under dynamic conditions. Results indicate that static vibration transfer path measurements can provide some insight into spiral bevel gear CI performance by identifying structural characteristics unique to each system that can affect specific CI response.

Effects of lead on Na+, K+-ATPase and hemolymph ion concentrations in the freshwater mussel Elliptio complanata

USGS Publications Warehouse

Mosher, Shad; Cope, W. Gregory; Weber, Frank X.; Shea, Damian; Kwak, Thomas J.

2012-01-01

Freshwater mussels are an imperiled fauna exposed to a variety of environmental toxicants such as lead (Pb) and studies are urgently needed to assess their health and condition to guide conservation efforts. A 28-day laboratory toxicity test with Pb and adult Eastern elliptio mussels (Elliptio complanata) was conducted to determine uptake kinetics and to assess the toxicological effects of Pb exposure. Test mussels were collected from a relatively uncontaminated reference site and exposed to a water-only control and five concentrations of Pb (as lead nitrate) ranging from 1 to 245 mu g/L in a static renewal test with a water hardness of 42 mg/L. Endpoints included tissue Pb concentrations, hemolymph Pb and ion (Na+, K+, Cl-, Ca2+) concentrations, and Na+, K+-ATPase enzyme activity in gill tissue. Mussels accumulated Pb rapidly, with tissue concentrations increasing at an exposure-dependent rate for the first 2 weeks, but with no significant increase from 2 to 4 weeks. Mussel tissue Pb concentrations ranged from 0.34 to 898 mu g/g dry weight, were strongly related to Pb in test water at every time interval (7, 14, 21, and 28 days), and did not significantly increase after day 14. Hemolymph Pb concentration was variable, dependent on exposure concentration, and showed no appreciable change with time beyond day 7, except for mussels in the greatest exposure concentration (245 mu g/L), which showed a significant reduction in Pb by 28 days, suggesting a threshold for Pb binding or elimination in hemolymph at concentrations near 1000 mu g/g. The Na+, K+-ATPase activity in the gill tissue of mussels was significantly reduced by Pb on day 28 and was highly correlated with tissue Pb concentration (R2 = 0.92; P = 0.013). The Na+, K+-ATPase activity was correlated with reduced hemolymph Na+ concentration at the greatest Pb exposure when enzyme activity was at 30% of controls. Hemolymph Ca2+ concentration increased significantly in mussels from the greatest Pb exposure and may be due to remobilization from the shell in an attempt to buffer the hemolymph against Pb uptake and toxicity. We conclude that Na+, K+-ATPase activity in mussels was adversely affected by Pb exposure, however, because the effects on activity were variable at the lower test concentrations, additional research is warranted over this range of exposures. (C) 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Critique on the use of the standardized avian acute oral toxicity test for first generation anticoagulant rodenticides

USGS Publications Warehouse

Vyas, Nimish B.; Rattner, Barnett A.

2012-01-01

Avian risk assessments for rodenticides are often driven by the results of standardized acute oral toxicity tests without regards to a toxicant's mode of action and time course of adverse effects. First generation anticoagulant rodenticides (FGARs) generally require multiple feedings over several days to achieve a threshold concentration in tissue and cause adverse effects. This exposure regimen is much different than that used in the standardized acute oral toxicity test methodology. Median lethal dose values derived from standardized acute oral toxicity tests underestimate the environmental hazard and risk of FGARs. Caution is warranted when FGAR toxicity, physiological effects, and pharmacokinetics derived from standardized acute oral toxicity testing are used for forensic confirmation of the cause of death in avian mortality incidents and when characterizing FGARs' risks to free-ranging birds.

THE RELATIONSHIP BETWEEN VARIOUS MODES OF SINGLE LEG POSTURAL CONTROL ASSESSMENT

PubMed Central

Schmitz, Randy

2012-01-01

Purpose/Background: While various techniques have been developed to assess the postural control system, little is known about the relationship between single leg static and functional balance. The purpose of the current study was to determine the relationship between the performance measures of several single leg postural stability tests. Methods: Forty six recreationally active college students (17 males, 29 females, 21±3 yrs, 173±10 cm) performed six single leg tests in a counterbalanced order: 1) Firm Surface-Eyes Open, 2) Firm Surface-Eyes Closed, 3) Multiaxial Surface-Eyes Open, 4) Multiaxial Surface-Eyes Closed, 5) Star Excursion Balance Test (posterior medial reach), 6) Single leg Hop-Stabilization Test. Bivariate correlations were conducted between the six outcome variables. Results: Mild to moderate correlations existed between the static tests. No significant correlations existed involving either of the functional tests. Conclusions: The results indicate that while performance of static balance tasks are mildly to moderately related, they appear to be unrelated to functional reaching or hopping movements, supporting the utilization of a battery of tests to determine overall postural control performance. Level of Evidence: 3b PMID:22666640

Rubber-like materials derived from biosourced phenolic resins

NASA Astrophysics Data System (ADS)

Amaral-Labat, G.; Grishechko, L. I.; Silva, G. F. B. Lenz e.; Kuznetsov, B. N.; Fierro, V.; Pizzi, A.; Celzard, A.

2017-07-01

The present work describes new gels derived from cheap, abundant and non-toxic wood bark extracts of phenolic nature, behaving like elastomers. Especially, we show that these materials might be used as rubber springs. Such amazing properties were obtained by a quite simple synthesis based on the autocondensation of flavonoid tannins in water at low pH in the presence of a plasticizer. After gelation and drying, the materials presented elastic properties that could be tuned from hard and brittle to quite soft and deformable, depending on the amount of plasticizer in the starting formulation. Not only the materials containing the relevant amount of plasticizer had stress-strain characteristics in quasi-static and cyclic compression similar to most commercial rubber springs, but they presented outstanding fire retardance, surviving 5 min in a flame at 1000°C in air. Neither flame propagation nor drips were noticed during the fire test, and the materials were auto-extinguishable. These excellent features make these materials potential substitutes to usual organic elastomers.

Biodecolorization of Reactive Yellow-2 by Serratia sp. RN34 Isolated from Textile Wastewater.

PubMed

Najme, Rabia; Hussain, Sabir; Maqbool, Zahid; Imran, Muhammad; Mahmood, Faisal; Manzoor, Hamid; Yasmeen, Tahira; Shehzad, Tanvir

2015-12-01

Remediation of colored textile wastewaters is a matter of interest. In this study, 49 bacteria were isolated from the textile wastewater and tested for their ability to decolorize reactive yellow-2 (RY2) dye. The most efficient isolate, RN34, was identified through amplification, sequencing, and phylogenetic analysis of its 16S rDNA and was designated as Serratia sp. RN34. This bacterium was also found capable of decolorizing other related reactive azo-dyes, including reactive black-5, reactive red-120, and reactive orange-16 but at varying rates. The optimum pH for decolorization of RY2 by the strain RN34 was 7.5 using yeast extract as cosubstrate under static incubation at 30 °C. The strain RN34 also showed potential to decolorize RY2 in the presence of considerable amounts of hexavalent chromium and sodium chloride. A phytotoxicity study demonstrated relatively reduced toxicity of RY2 decolorized products on Vigna radiata plant as compared to the uninoculated RY2 solution.

Ephyra jellyfish as a new model for ecotoxicological bioassays.

PubMed

Faimali, M; Garaventa, F; Piazza, V; Costa, E; Greco, G; Mazzola, V; Beltrandi, M; Bongiovanni, E; Lavorano, S; Gnone, G

2014-02-01

The aim of this study was a preliminary investigation on the possibility of using the ephyra of Scyphozoan jellyfish Aurelia aurita (Linnaeus, 1758), the common moon jellyfish, as an innovative model organism in marine ecotoxicology. A series of sequential experiments have been carried out in laboratory in order to investigate the influence of different culturing and methodological parameters (temperature, photoperiod, ephyrae density and age) on behavioural end-points (% of Frequency of Pulsations) and standardize a testing protocol. After that, the organisms have been exposed to two well known reference toxic compounds (Cadmium Nitrate and SDS) in order to analyse the acute and behavioural responses during static exposure. Results of this work indicate that the proposed behavioural end-point, frequency of pulsations (Fp), is an easily measurable one and can be used coupled with an acute one (immobilization) and that ephyrae of jellyfish are very promising model organisms for ecotoxicological investigation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Low-speed Aerodynamic Investigations of a Hybrid Wing Body Configuration

NASA Technical Reports Server (NTRS)

Vicroy, Dan D.; Gatlin, Gregory M.; Jenkins, Luther N.; Murphy, Patrick C.; Carter, Melissa B.

2014-01-01

Two low-speed static wind tunnel tests and a water tunnel static and dynamic forced-motion test have been conducted on a hybrid wing-body (HWB) twinjet configuration. These tests, in addition to computational fluid dynamics (CFD) analysis, have provided a comprehensive dataset of the low-speed aerodynamic characteristics of this nonproprietary configuration. In addition to force and moment measurements, the tests included surface pressures, flow visualization, and off-body particle image velocimetry measurements. This paper will summarize the results of these tests and highlight the data that is available for code comparison or additional analysis.

Photoenhanced toxicity of a weathered oil on Ceriodaphnia dubia reproduction

USGS Publications Warehouse

Calfee, R.D.; Little, E.E.; Cleveland, L.; Barron, M.G.

1999-01-01

Traditionally, the toxic effects of petroleum have been investigated by conducting studies in the absence of ultraviolet radiation (UV). Photomediated toxicity is often not considered, and the toxic effects of an oil spill can be grossly underestimated. The toxicity of a weathered oil collected from a monitoring well at an abandoned oil field toCeriodaphnia dubia was examined in the presence of UV. A solar simulator equipped with UVB, UVA, and cool white lamps was used to generate environmentally comparable solar radiation intensities.C. dubia were exposed to six concentrations of water accommodated fractions (WAF) of weathered oil in conjunction with three levels of laboratory simulated UV (Reference = < 0.002 μW/cm2UVB; 3.0 μW/cm2UVA; Low = 0.30 μW/cm2 UVB; 75.0 μW/cm2 UVA; High = 2.0 μW/cm2 UVB; 340.0 μW/cm2UVA) and visible light. Seven day static renewal bioassays were used to characterize WAF/UV toxicity. WAF toxicity significantly (p < 0.05) increased when the organisms were exposed to WAF in the presence of UV. The photoenhanced toxicity of the WAF increased with WAF concentration within each UV regime. Relative to the reference light regime, the average number of neonates from adults exposed to 1.6 mg TPH/L decreased significantly by 20% within the low light regime, and by 60% within the high light regime. These results indicate that organisms exposed to dissolved-phase weathered oil in the presence of environmentally realistic solar radiation, exhibit 1.3–2.5 times greater sensitivity, relative to organisms exposed under traditional laboratory fluorescent lighting.

Review of toxicity studies performed on an underground coal gasification condensate water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barker, F.P.

1987-09-01

Three studies related to the toxicity of underground coal gasification (UCG) waters have bee conducted: (1) toxicity study of UCG water and its fractions as determined by the Microtox test, (2) toxicity study of biotreated UCG water as determined by the Microtox test, and (3) toxicity study of UCG water to macroinvertebrates. The results of these studies are summarized herein. The gas condensate water from the UCG process is extremely toxic as determined by assays with photoluminescent bacteria (Microtox), benthic (bottom-dwelling) macroinvertebrates (mayflies), and Daphnia magna (water flea). Microtox bioassays reveal that the toxic components of the water reside inmore » both the organophilic and hydrophilic fractions, although the organophilic fraction is notably more toxic. A sequential treatment process reduced the toxicity of the UCG water, as measured by the Microtox test. Solvent extraction (to remove phenols) followed by ammonia stripping yielded a less toxic water. Additional treatment by activated sludge further reduced toxicity. Finally, the addition of powdered activated carbon to the activated sludge yielded the least toxic water. A bioassay technique was developed for lotic (running water) macroinvertebrates (Drunella doddsi and Iron longimanus). The toxicity results were compared with results from the traditional test animal, Daphnia magna. Short-term exposures to the UCG waters were more toxic to Daphnia magna than to Drunella doddsi or Iron longimanus, although the toxicity values begin to merge with longer test exposure. The greater toxicity seems to be related to a thinner exoskeleton. 26 refs., 2 figs., 6 tabs.« less

Static investigation of several yaw vectoring concepts on nonaxisymmetric nozzles

NASA Technical Reports Server (NTRS)

Mason, M. L.; Berrier, B. L.

1985-01-01

A test has been conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to determine the flow-turning capability and the effects on nozzle internal performance of several yaw vectoring concepts. Nonaxisymmetric convergent-divergent nozzles with throat areas simulating dry and afterburning power settings and single expansion ramp nozzles with a throat area simulating a dry power setting were modified for yaw thrust vectoring. Forward-thrust and pitch-vectored nozzle configurations were tested with each yaw vectoring concept. Four basic yaw vectoring concepts were investigated on the nonaxisymmetric convergent-divergent nozzles: (1) translating sidewall; (2) downstream (of throat) flaps; (3) upstream (of throat) port/flap; and (4) powered rudder. Selected combinations of the rudder with downstream flaps or upstream port/flap were also tested. A single yaw vectoring concept, post-exit flaps, was investigated on the single expansion ramp nozzles. All testing was conducted at static (no external flow) conditions and nozzle pressure ratios varied from 2.0 up to 10.0.

A static investigation of the thrust vectoring system of the F/A-18 high-alpha research vehicle

NASA Technical Reports Server (NTRS)

Mason, Mary L.; Capone, Francis J.; Asbury, Scott C.

1992-01-01

A static (wind-off) test was conducted in the static test facility of the Langley 16-foot Transonic Tunnel to evaluate the vectoring capability and isolated nozzle performance of the proposed thrust vectoring system of the F/A-18 high alpha research vehicle (HARV). The thrust vectoring system consisted of three asymmetrically spaced vanes installed externally on a single test nozzle. Two nozzle configurations were tested: A maximum afterburner-power nozzle and a military-power nozzle. Vane size and vane actuation geometry were investigated, and an extensive matrix of vane deflection angles was tested. The nozzle pressure ratios ranged from two to six. The results indicate that the three vane system can successfully generate multiaxis (pitch and yaw) thrust vectoring. However, large resultant vector angles incurred large thrust losses. Resultant vector angles were always lower than the vane deflection angles. The maximum thrust vectoring angles achieved for the military-power nozzle were larger than the angles achieved for the maximum afterburner-power nozzle.

Sodium cyanide induced alteration in the whole animal oxygen consumption and behavioural pattern of freshwater fish Labeo rohita.

PubMed

David, Muniswamy; Sangeetha, Jeyabalan; Harish, Etigemane R

2015-03-01

Sodium cyanide is a common environmental pollutant which is mainly used in many industries such as mining, electroplating, steel manufacturing, pharmaceutical production and other specialized applications including dyes and agricultural products. It enters aquatic environment through effluents from these industries. Static renewal bioassay test has been conducted to determine LC, of sodium cyanide on indigenous freshwater carp, Labeo rohita. The behavioural pattern and oxygen consumption were observed in fish at both lethal and sub lethal concentrations. Labeo rohita in toxic media exhibited irregular and erratic swimming movements, hyper excitability, loss of equilibrium and shrinking to the bottom, which may be due to inhibition of cytochrome C oxidase activity and decreased blood pH. The combination of cytotoxic hypoxia with lactate acidosis depresses the central nervous system resulting in respiratory arrest and death. Decrease in oxygen consumption was observed at both lethal and sub lethal concentrations of sodium cyanide. Mortality was insignificant at sub lethal concentration test when fishes were found under stress. Consequence of impaired oxidative metabolism and elevated physiological response by fish against sodium cyanide stress showed alteration in respiratory rate.

Large Deformation Dynamic Bending of Composite Beams

NASA Technical Reports Server (NTRS)

Derian, E. J.; Hyer, M. W.

1986-01-01

Studies were conducted on the large deformation response of composite beams subjected to a dynamic axial load. The beams were loaded with a moderate eccentricity to promote bending. The study was primarily experimental but some finite element results were obtained. Both the deformation and the failure of the beams were of interest. The static response of the beams was also studied to determine potential differences between the static and dynamic failure. Twelve different laminate types were tested. The beams were loaded dynamically with a gravity driven impactor traveling at 19.6 ft/sec and quasi-static tests were conducted on identical beams in a displacement controlled manner. For laminates of practical interest, the failure modes under static and dynamic loadings were identical. Failure in most of the laminate types occurred in a single event involving 40% to 50% of the plies. However, failure in laminates with 30 deg or 15 deg off-axis plies occured in several events. All laminates exhibited bimodular elastic properties. Using empirically determined flexural properties, a finite element analysis was reasonably accurate in predicting the static and dynamic deformation response.

Equilibrium disorders in workers exposed to mixed solvents.

PubMed

Giorgianni, Concetto; Tanzariello, Mariagiuseppina; De Pasquale, Domenico; Brecciaroli, Renato; Spatari, Giovanna

2018-02-06

Organic solvents cause diseases of the vestibular system. However, little is known regarding the correlation between vestibular damage and exposure to organic solvents below threshold limit values. The best measure by which to evaluate vestibular disorders is static and dynamic posturography. The aim of this study was to evaluate equilibrium disorders via static and dynamic posturography in workers without clear symptoms and exposed to low doses of mixed solvents. 200 subjects were selected. Using an Otometrics device (Madsen, Denmark), all subjects endured static and dynamic posturography testing with both eyes-open and eyes-closed conditions. Results were compared with a control group of unexposed individuals. Based on the obtained data, the following results can be drawn: (a) subjects exposed to mixtures of solvents show highly significant differences regarding all static and dynamic posturography parameters in comparison to the control group; (b) posturography testing has proven to be a valid means by which to detect subliminal equilibrium disorders in subjects exposed to solvents. We can confirm that refinery workers exposed to mixtures of solvents can present subliminal equilibrium disorders. Early diagnosis of the latter is made possible by static and dynamic posturography.

Sequential Test Strategies for Multiple Fault Isolation

NASA Technical Reports Server (NTRS)

Shakeri, M.; Pattipati, Krishna R.; Raghavan, V.; Patterson-Hine, Ann; Kell, T.

1997-01-01

In this paper, we consider the problem of constructing near optimal test sequencing algorithms for diagnosing multiple faults in redundant (fault-tolerant) systems. The computational complexity of solving the optimal multiple-fault isolation problem is super-exponential, that is, it is much more difficult than the single-fault isolation problem, which, by itself, is NP-hard. By employing concepts from information theory and Lagrangian relaxation, we present several static and dynamic (on-line or interactive) test sequencing algorithms for the multiple fault isolation problem that provide a trade-off between the degree of suboptimality and computational complexity. Furthermore, we present novel diagnostic strategies that generate a static diagnostic directed graph (digraph), instead of a static diagnostic tree, for multiple fault diagnosis. Using this approach, the storage complexity of the overall diagnostic strategy reduces substantially. Computational results based on real-world systems indicate that the size of a static multiple fault strategy is strictly related to the structure of the system, and that the use of an on-line multiple fault strategy can diagnose faults in systems with as many as 10,000 failure sources.

Development of an advanced pitch active control system for a wide body jet aircraft

NASA Technical Reports Server (NTRS)

Guinn, Wiley A.; Rising, Jerry J.; Davis, Walt J.

1984-01-01

An advanced PACS control law was developed for a commercial wide-body transport (Lockheed L-1011) by using modern control theory. Validity of the control law was demonstrated by piloted flight simulation tests on the NASA Langley visual motion simulator. The PACS design objective was to develop a PACS that would provide good flying qualities to negative 10 percent static stability margins that were equivalent to those of the baseline aircraft at a 15 percent static stability margin which is normal for the L-1011. Also, the PACS was to compensate for high-Mach/high-g instabilities that degrade flying qualities during upset recoveries and maneuvers. The piloted flight simulation tests showed that the PACS met the design objectives. The simulation demonstrated good flying qualities to negative 20 percent static stability margins for hold, cruise and high-speed flight conditions. Analysis and wind tunnel tests performed on other Lockheed programs indicate that the PACS could be used on an advanced transport configuration to provide a 4 percent fuel savings which results from reduced trim drag by flying at negative static stability margins.

Study of Geometric Porosity on Static Stability and Drag Using Computational Fluid Dynamics for Rigid Parachute Shapes

NASA Technical Reports Server (NTRS)

Greathouse, James S.; Schwing, Alan M.

2015-01-01

This paper explores use of computational fluid dynamics to study the e?ect of geometric porosity on static stability and drag for NASA's Multi-Purpose Crew Vehicle main parachute. Both of these aerodynamic characteristics are of interest to in parachute design, and computational methods promise designers the ability to perform detailed parametric studies and other design iterations with a level of control previously unobtainable using ground or flight testing. The approach presented here uses a canopy structural analysis code to define the inflated parachute shapes on which structured computational grids are generated. These grids are used by the computational fluid dynamics code OVERFLOW and are modeled as rigid, impermeable bodies for this analysis. Comparisons to Apollo drop test data is shown as preliminary validation of the technique. Results include several parametric sweeps through design variables in order to better understand the trade between static stability and drag. Finally, designs that maximize static stability with a minimal loss in drag are suggested for further study in subscale ground and flight testing.

Structural characterization of a first-generation articulated-truss joint for space crane application

NASA Technical Reports Server (NTRS)

Sutter, Thomas R.; Wu, K. Chauncey; Riutort, Kevin T.; Laufer, Joseph B.; Phelps, James E.

1992-01-01

A first-generation space crane articulated-truss joint was statically and dynamically characterized in a configuration that approximated an operational environment. The articulated-truss joint was integrated into a test-bed for structural characterization. Static characterization was performed by applying known loads and measuring the corresponding deflections to obtain load-deflection curves. Dynamic characterization was performed using modal testing to experimentally determine the first six mode shapes, frequencies, and modal damping values. Static and dynamic characteristics were also determined for a reference truss that served as a characterization baseline. Load-deflection curves and experimental frequency response functions are presented for the reference truss and the articulated-truss joint mounted in the test-bed. The static and dynamic experimental results are compared with analytical predictions obtained from finite element analyses. Load-deflection response is also presented for one of the linear actuators used in the articulated-truss joint. Finally, an assessment is presented for the predictability of the truss hardware used in the reference truss and articulated-truss joint based upon hardware stiffness properties that were previously obtained during the Precision Segmented Reflector (PSR) Technology Development Program.

A REVIEW OF SINGLE SPECIES TOXICITY TESTS: ARE THE TESTS RELIABLE PREDICTORS OF AQUATIC ECOSYSTEM COMMUNITY RESPONSES?

EPA Science Inventory

This document provides a comprehensive review to evaluate the reliability of indicator species toxicity test results in predicting aquatic ecosystem impacts, also called the ecological relevance of laboratory single species toxicity tests.

Comparison of physical fitness between rice farmers with and without chronic low back pain: a cross-sectional study.

PubMed

Taechasubamorn, Panada; Nopkesorn, Tawesak; Pannarunothai, Supasit

2010-12-01

To compare physical fitness between rice farmers with chronic low back pain (CLBP) and a healthy control group. Sixty-eight rice farmers with CLBP were matched according to age and sex with healthy farmers. All subjects underwent nine physical fitness tests for body composition, lifting capacity, static back extensor endurance, leg strength, static abdominal endurance, handgrip strength, hamstring flexibility, posterior leg and back muscles flexibility and abdominal flexibility. There was no significant difference between CLBP and healthy groups for all tests, except the static back extensor endurance. The back extensor endurance times of the CLBP group was significantly lower than that of the control group (p = 0.002). Static back extensor endurance is the deficient physical fitness in CLBP rice farmers. Back extensor endurance training should be emphasized in both prevention and rehabilitation programs.

Scaling Effects in Carbon/Epoxy Laminates Under Transverse Quasi-Static Loading

NASA Technical Reports Server (NTRS)

Nettles, Alan T.; Douglas, Michael J.; Estes, Eric E.

1999-01-01

Scaling effects were considered for 8, 16, 32, and 64 ply IM-7/8551-7 carbon/epoxy composites plates transversely loaded to the first significant load drop by means of both a quasi-static and an equivalent impact force. The resulting damage was examined by x-ray and photomicroscopy analysis. Load-deflection curves were generated for the quasi-static tests and the resulting indentation depth was measured. Results showed that the load-deflection data scaled well for most of the various thicknesses of plates. However, damage did not scale as well. No correlation could be found between dent depth and any of the other parameters measured in this study. The impact test results showed that significantly less damage was formed compared to the quasi- static results for a given maximum transverse load. The criticality of ply-level scaling (grouping plies) was also examined.

Anodonta imbecillis copper sulfate reference toxicant test, Clinch River - Environmental Restoration Program (CR-ERP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simbeck, D.J.

1997-06-01

Reference toxicant testing using juvenile freshwater mussels was conducted as part of the CR-ERP biomonitoring study of Clinch River sediments to assess the sensitivity of test organisms and the overall performance of the test. Tests were conducted using moderately hard synthetic water spiked with known concentrations of copper as copper sulfate. Toxicity testing of copper sulfate reference toxicant was conducted from May 12-21, 1993. The organisms used for testing were juvenile fresh-water mussels (Anodonta imbecillis). Results from this test showed an LC{sub 50} value of 1.12 mg Cu/L which is lower than the value of 2.02 mg Cu/L obtained inmore » a previous test. Too few tests have been conducted with copper as the toxicant to determine a normal range of values.« less

Quasi-Static Viscoelasticity Loading Measurements of an Aircraft Tire

NASA Technical Reports Server (NTRS)

Mason, Angela J.; Tanner, John A.; Johnson, Arthur R.

1997-01-01

Stair-step loading, cyclic loading, and long-term relaxation tests were performed on an aircraft tire to observe the quasi-static viscoelastic response of the tire. The data indicate that the tire continues to respond viscoelastically even after it has been softened by deformation. Load relaxation data from the stair-step test at the 15,000-lb loading was fit to a monotonically decreasing Prony series.

Strain energy release rate as a function of temperature and preloading history utilizing the edge delamination fatique test method

NASA Technical Reports Server (NTRS)

Zimmerman, Richard S.; Adams, Donald F.

1989-01-01

Static laminate and tension-tension fatigue tests of IM7/8551-7 composite materials was performed. The Edge Delamination Test (EDT) was utilized to evaluate the temperature and preloading history effect on the critical strain energy release rate. Static and fatigue testing was performed at room temperature and 180 F (82 C). Three preloading schemes were used to precondition fatigue test specimens prior to performing the normal tension-tension fatigue EDT testing. Computer software was written to perform all fatigue testing while monitoring the dynamic modulus to detect the onset of delamination and record the test information for later retrieval and reduction.

Saturn V First Stage Lowered to the Ground After Static Test

NASA Technical Reports Server (NTRS)

1966-01-01

This vintage photograph shows the 138-foot long first stage of the Saturn V being lowered to the ground following a successful static test firing at Marshall Space flight Center's S-1C test stand. The firing provided NASA engineers information on the booster's systems. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

Studies of the environmental fate and effect of aircraft deicing fluids: Detection of 5-methyl-1H-benzotriazole in the fathead minnow (Pimephales promelas)

USGS Publications Warehouse

Cancilla, Devon A.; Baird, J.C.; Geis, S.W.; Corsi, Steven R.

2003-01-01

This paper presents the results of a number of field and laboratory studies to evaluate the environmental impact of aircraft deicing and anti-icing fluids (ADAFs) on aquatic systems. Both 5-methyl-1H-benzotriazole (5-MeBt) and 4-methyl-1H-benzotriazole (4-MeBt), known additives to ADAFs, were found in whole-tissue extracts from minnows placed downstream of an effluent outfall that receives ADAF contaminated runoff from General Mitchell International Airport (Milwaukee, WI, USA). Neither of these compounds was detected in tissues from minnows placed upstream from the airport. A toxicity assessment of water collected during the minnow exposure studies utilizing Hyalella azteca, Pimephales promelas, and Ceriodaphnia dubia showed greater toxicity in a secondary airport outfall containing ADAFs when compared to upstream non-ADAF-contaminated samples. In two 28-d static renewal tests using 5-MeBt laboratory-fortified waters, 5-MeBt was detected in whole-tissue extracts of minnows at all concentrations tested. In studies using laboratory water fortified with 5-MeBt, the median lethal concentration (LC50) of 5-MeBt for P. promelas was found to be 22.0 mg/L. The LC50 for C. dubia to 5-MeBt laboratory-fortified water was found to be 81.3 mg/L. The 25% inhibition concentration (IC25) of 5-MeBt for the green alga Selenastrum capricornutum was 23.2 mg/L, and the average median effective concentration (EC50) for Microtox was 4.25 mg/L. The results of these field and lab studies indicate that additives, other than glycols, used in aircraft deicing fluids can be found in aquatic systems and may be of greater risk than previously believed.

Studies of the environmental fate and effect of aircraft deicing fluids: detection of 5-methyl-1H-benzotriazole in the fathead minnow (Pimephales promelas).

PubMed

Cancilla, Devon A; Baird, J Christopher; Geis, Steven W; Corsi, Steven R

2003-01-01

This paper presents the results of a number of field and laboratory studies to evaluate the environmental impact of aircraft deicing and anti-icing fluids (ADAFs) on aquatic systems. Both 5-methyl-1H-benzotriazole (5-MeBt) and 4-methyl-1H-benzotriazole (4-MeBt), known additives to ADAFs, were found in whole-tissue extracts from minnows placed downstream of an effluent outfall that receives ADAF contaminated runoff from General Mitchell International Airport (Milwaukee, WI, USA). Neither of these compounds was detected in tissues from minnows placed upstream from the airport. A toxicity assessment of water collected during the minnow exposure studies utilizing Hyalella azteca, Pimephales promelas, and Ceriodaphnia dubia showed greater toxicity in a secondary airport outfall containing ADAFs when compared to upstream non-ADAF-contaminated samples. In two 28-d static renewal tests using 5-MeBt laboratory-fortified waters, 5-MeBt was detected in whole-tissue extracts of minnows at all concentrations tested. In studies using laboratory water fortified with 5-MeBt, the median lethal concentration (LC50) of 5-MeBt for P. promelas was found to be 22.0 mg/L. The LC50 for C. dubia to 5-MeBt laboratory-fortified water was found to be 81.3 mg/L. The 25% inhibition concentration (IC25) of 5-MeBt for the green alga Selenastrum capricornutum was 23.2 mg/L, and the average median effective concentration (EC50) for Microtox was 4.25 mg/L. The results of these field and lab studies indicate that additives, other than glycols, used in aircraft deicing fluids can be found in aquatic systems and may be of greater risk than previously believed.

Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teng, S.; Tebby, C.

Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro – in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-timemore » cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. - Highlights: • We could predict cell response over repeated exposure to mixtures of cosmetics. • Compounds acted independently on the cells. • Metabolic interactions impacted exposure concentrations to the compounds.« less

Applicability of ambient toxicity testing to national or regional water-quality assessment

USGS Publications Warehouse

Elder, J.F.

1989-01-01

Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water quality assessments. These purposes may include identification that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. A wide variety of toxicity test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the full selections made relative to four characteristics: (1) test species, (2) endpoints (acute or chronic), (3) test enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity test approachs vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing is more likely to meet these needs than are the procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful interpretation of ambient test results depend on the existence of accompanying chemical analysis of the ambient media. The ambient test substance may be water or sediments. Sediment tests have had limited application, but they are useful because of the fact that most toxicants tend to accumulate in sediments, and many test species either inhabit the sediments or are in frequent contact with them. Biochemical testing methods, which have been developing rapidly in recent years, are likely to be among the most useful procedures for large-scale water quality assessments. They are relatively rapid and simple, and more importantly, they focus on biochemical changes that are the initial responses of virtually all organisms to environmental stimuli. Most species are sensitive to relatively few toxicants and their sensitivities vary as conditions change. One of the most informative approaches for toxicity testing is to combine biochemical tests with other test methods in a ' battery or tests ' that is diversified enough to characterize different types of toxicants and different trophic levels. (Lantz-PTT)

Influence of flow-through and renewal exposures on the toxicity of copper to rainbow trout

USGS Publications Warehouse

Welsh, P.G.; Lipton, J.; Mebane, C.A.; Marr, J.C.A.

2008-01-01

We examined changes in water chemistry and copper (Cu) toxicity in three paired renewal and flow-through acute bioassays with rainbow trout (Oncorhynchus mykiss). Test exposure methodology influenced both exposure water chemistry and measured Cu toxicity. Ammonia and organic carbon concentrations were higher and the fraction of dissolved Cu lower in renewal tests than in paired flow-through tests. Cu toxicity was also lower in renewal tests; 96 h dissolved Cu LC50 values were 7-60% higher than LC50s from matching flow-through tests. LC50 values in both types of tests were related to dissolved organic carbon (DOC) concentrations in exposure tanks. Increases in organic carbon concentrations in renewal tests were associated with reduced Cu toxicity, likely as a result of the lower bioavailability of Cu-organic carbon complexes. The biotic ligand model of acute Cu toxicity tended to underpredict toxicity in the presence of DOC. Model fits between predicted and observed toxicity were improved by assuming that only 50% of the measured DOC was reactive, and that this reactive fraction was present as fulvic acid. ?? 2007 Elsevier Inc. All rights reserved.

Significance of Intratracheal Instillation Tests for the Screening of Pulmonary Toxicity of Nanomaterials.

PubMed

Morimoto, Yasuo; Izumi, Hiroto; Yoshiura, Yukiko; Fujisawa, Yuri; Fujita, Katsuhide

Inhalation tests are the gold standard test for the estimation of the pulmonary toxicity of respirable materials. Intratracheal instillation tests have been used widely, but they yield limited evidence of the harmful effects of respirable materials. We reviewed the effectiveness of intratracheal instillation tests for estimating the hazards of nanomaterials, mainly using research papers featuring intratracheal instillation and inhalation tests centered on a Japanese national project. Compared to inhalation tests, intratracheal instillation tests induced more acute inflammatory responses in the animal lung due to a bolus effect regardless of the toxicity of the nanomaterials. However, nanomaterials with high toxicity induced persistent inflammation in the chronic phase, and nanomaterials with low toxicity induced only transient inflammation. Therefore, in order to estimate the harmful effects of a nanomaterial, an observation period of 3 months or 6 months following intratracheal instillation is necessary. Among the endpoints of pulmonary toxicity, cell count and percentage of neutrophil, chemokines for neutrophils and macrophages, and oxidative stress markers are considered most important. These markers show persistent and transient responses in the lung from nanomaterials with high and low toxicity, respectively. If the evaluation of the pulmonary toxicity of nanomaterials is performed in not only the acute but also the chronic phase in order to avoid the bolus effect of intratracheal instillation and inflammatory-related factors that are used as endpoints of pulmonary toxicity, we speculate that intratracheal instillation tests can be useful for screening for the identification of the hazard of nanomaterials through pulmonary inflammation.

Vestibular afferent responses to linear accelerations in the alert squirrel monkey

NASA Technical Reports Server (NTRS)

Somps, Christopher J.; Schor, Robert H.; Tomko, David L.

1994-01-01

The spontaneous activity of 40 otolith afferents and 44 canal afferents was recorded in 4 alert, intact squirrel monkeys. Polarization vectors and response properties of otolith afferents were determined during static re-orientations relative to gravity and during Earth-horizontal, sinusoidal, linear oscillations. Canal afferents were tested for sensitivity to linear accelerations. For regular otolith afferents, a significant correlation between upright discharge rate and sensitivity to dynamic acceleration in the horizontal plane was observed. This correlation was not present in irregular units. The sensitivity of otolith afferents to both static tilts and dynamic linear acceleration was much greater in irregularly discharging units than in regularly discharging units. The spontaneous activity and static and dynamic response properties of regularly discharging otolith afferents were similar to those reported in barbiturate-anesthetized squirrel monkeys. Irregular afferents also had similar dynamic response properties when compared to anesthetized monkeys. However, this sample of irregular afferents in alert animals had higher resting discharge rates and greater sensitivity to static tilts. The majority of otolith polarization vectors were oriented near the horizontal in the plane of the utricular maculae; however, directions of maximum sensitivity were different during dynamic and static testing. Canal afferents were not sensitive to static tilts or linear oscillations of the head.

The Preparation of Some Compounds for Testing as Insect Repellents

DTIC Science & Technology

1945-12-28

have been submitted for 90-day subacute toxicity studies « 0-7139, 0-7209 and 0-7227 have passed acute toxicity tests (0- 7227 with reservations...but have not been submitted for 90-day subacute toxicity studies , 0-7392, 0-7430 and 0-13058 have been submitted for acute toxicity tests. Forty-fivo...evaluate adequately the promising candidate insect repellents prepared under this contract. Some toxicity studies as indicated above are being made

The effect of visuals on non-native English students' learning of the basic principles and laws of motion

NASA Astrophysics Data System (ADS)

Yang, Quan

2001-10-01

This study, involving 154 undergraduate college students in China, was conducted to determine whether the surface structure of visual graphics affect content learning when the learner was a non-native English speaker and learning took place in a non-English speaking environment. Instruction with concrete animated graphics resulted in significantly higher achievement, when compared to instruction with concrete static, abstract static, abstract animated graphics or text only without any graphical illustrations. It was also found, unexpectedly, the text-only instruction resulted in the second best achievement, significantly higher than instruction with concrete static, abstract static, and abstract animated graphics. In addition, there was a significant interaction with treatment and test item, which indicated that treatment effects on graphic-specific items differed from those on definitional items. Additional findings indicated that relation to graphics directly or indirectly from the text that students studied had little impact on their performance in the posttests. Further, 51% of the participants indicated that they relied on some graphical images to answer the test questions and 19% relied heavily on graphics when completing the tests. In conclusion, concrete graphics when combined with animation played a significant role in enhancing ESL student performance and enabled the students to achieve the best learning outcomes as compared to abstract animated, concrete static, and abstract static graphics. This result suggested a significant innovation in the design and development of ESL curriculum in computer-based instruction, which would enable ESL students to perform better and achieve the expected outcomes in content area learning.

The static breaking technique for sustainable and eco-environmental coal mining.

PubMed

Bing-yuan, Hao; Hui, Huang; Zi-jun, Feng; Kai, Wang

2014-01-01

The initiating explosive devices are prohibited in rock breaking near the goaf of the highly gassy mine. It is effective and applicable to cracking the hard roof with static cracking agent. By testing the static cracking of cubic limestone (size: 200 × 200 × 200 mm) with true triaxial rock mechanics testing machine under the effect of bidirectional stress and by monitoring the evolution process of the cracks generated during the acoustic emission experiment of static cracking, we conclude the following: the experiment results of the acoustic emission show that the cracks start from the lower part of the hole wall until they spread all over the sample. The crack growth rate follows a trend of "from rapidness to slowness." The expansion time is different for the two bunches of cracks. The growth rates can be divided into the rapid increasing period and the rapid declining period, of which the growth rate in declining period is less than that in the increasing period. Also, the growth rate along the vertical direction is greater than that of the horizontal direction. Then the extended model for the static cracking is built according to the theories of elastic mechanics and fracture mechanics. Thus the relation formula between the applied forces of cracks and crack expansion radius is obtained. By comparison with the test results, the model proves to be applicable. In accordance with the actual geological situation of Yangquan No. 3 Mine, the basic parameters of manpower manipulated caving breaking with static crushing are settled, which reaps bumper industrial effects.

Galleria mellonella (greater wax moth) larvae as a model for antibiotic susceptibility testing and acute toxicity trials.

PubMed

Ignasiak, Katarzyna; Maxwell, Anthony

2017-08-29

Infectivity trials and toxicity testing in rodents are important prerequisites to the use of compounds in man. However, trials in rats and mice are expensive and there are ethical considerations. Galleria mellonella (greater wax moth) larvae are a potential alternative. We have assessed the use of these insects in infectivity trials and toxicity testing. Using four bacterial species (two Gram-negative and two Gram-positive) we have assessed the efficacy of four antibiotics against infections in Galleria and compared the antibiotic susceptibility with that in humans. In general, we find a good correlation. Similarly, we have assessed 11 compounds (initially tested blind) for their toxicity in Galleria and compared this with toxicity trials in mice and rats. Again we found a good correlation between toxicity in Galleria and that in rodents. We have found, in our hands, that G. mellonella larvae can be used in infectivity trials and toxicity testing, and that these assays represent an inexpensive and readily executable alternative to testing in rodents.

A preliminary study of static and dynamic balance in sedentary obese young adults: the relationship between BMI, posture and postural balance.

PubMed

do Nascimento, J A; Silva, C C; Dos Santos, H H; de Almeida Ferreira, J J; de Andrade, P R

2017-12-01

The aim of this study was to evaluate the postural control of obese young adults with normal body mass index during different static (bipedic and unipedic support) and dynamic postural conditions (gait velocity and limits of stability) in order to compare the static and dynamic balance of these individuals. A cross-sectional quantitative study was carried out to evaluate static and dynamic balance in 25 sedentary individuals. The sample was divided into two groups, 10 in the normal-weight group (24.70 ± 3.89 years and 21.5 ± 1.66 kg m -2 ) and 15 in the obese group (26.80 ± 5.16 years and 35.66 ± 4.29 kg m -2 ). Postural evaluation was performed through visual inspection, and balance analyses were performed using the Timed Up & Go test (TUGT) and Balance System (Biodex). Descriptive analyses, Fisher's exact test and Mann Whitney U-tests were performed using the Statistical Package for Social Sciences (SPSS - 20.0, Armonk, NY) software. Most of the obese volunteers presented postural alterations, such as head protrusion (47.6%), hyperkyphosis (46.7%) and hyperlordosis (26.7%). Medial-lateral dynamic displacement, risk of falls and mean time to perform the limits of stability test and TUGT were higher for obese subjects (P < 0.05), while there were no significant differences between the groups (P > 0.05) for static balance tests for either bipedal or unipedal tasks. The disadvantage presented by the young obese subjects occurs in dynamic activities, representing worse balance and an increase in time needed to accomplish these activities. © 2017 World Obesity Federation.

Necessity of toxicity assessment in Turkish industrial discharges (examples from metal and textile industry effluents).

PubMed

Sponza, Delia Teresa

2002-01-01

Toxicity of some organic and inorganic chemicals to microorganisms is an important consideration in assessing their environmental impact against their economic benefits. Microorganisms play an important role in several environmental processes, both natural and engineered. Some organic and inorganics at toxic levels have been detected in industrial discharges resulting in plant upsets and discharge permit violations. In addition to this, even though in some cases the effluent wastewater does not exceed the discharge limits, the results of toxicity tests show potential toxicity. Toxicity knowledge of effluents can benefit treatment plant operators in optimising plant operation, setting pre-treatment standards, and protecting receiving water quality and in establishing sewer discharge permits to safeguard the plant. In the Turkish regulations only toxicity dilution factor (TDF) with fish is part of the toxicity monitoring program of permissible wastewater discharge. In various countries, laboratory studies involving the use of different organisms and protocol for toxicity assessment was conducted involving a number of discharges. In this study, it was aimed to investigate the acute toxicity of textile and metal industry wastewaters by traditional and enrichment toxicity tests and emphasize the importance of toxicity tests in wastewater discharge regulations. The enrichment toxicity tests are novel applications and give an idea whether there is potential toxicity or growth limiting and stimulation conditions. Different organisms were used such as bacteria (Floc and Coliform bacteria) algae (Chlorella sp.). fish (Lepistes sp.) and protozoan (Vorticella sp.) to represent four tropic levels. The textile industry results showed acute toxicity for at least one organism in 8 out of 23 effluent samples. Acute toxicity for at least two organisms in 7 out of 23 effluent sampling was observed for the metal industry. The toxicity test results were assessed with chemical analyses such as COD, BOD, color and heavy metals. It was observed that the toxicity of the effluents could not be explained by using physicochemical analyses in 5 cases for metal and 4 cases for the textile industries. The results clearly showed that the use of bioassay tests produce additional information about the toxicity potential of industrial discharges and effluents.

Deformation behavior of welded steel sandwich panels under quasi-static loading

DOT National Transportation Integrated Search

2011-03-01

This report describes engineering studies that were conducted to examine the deformation behavior of flat, welded steel sandwich panels under two quasi-static loading conditions: (1) uniaxial compression; and (2) bending with an indenter. Testing and...

Measurement of the True Dynamic and Static Pressures in Flight

NASA Technical Reports Server (NTRS)

Kiel, Georg

1939-01-01

In this report, two reliable methods are presented, with the aid of which the undisturbed flight dynamic pressure and the true static pressure may be determined without error. These problems were solved chiefly through practical flight tests.

49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

Code of Federal Regulations, 2014 CFR

2014-10-01

... normal operating temperature. (5) The heating, ventilation and air conditioning (HVAC) system or a dedicated heating or air conditioner system must be operating on high, and the vents must be open and...

49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

Code of Federal Regulations, 2013 CFR

2013-10-01

... normal operating temperature. (5) The heating, ventilation and air conditioning (HVAC) system or a dedicated heating or air conditioner system must be operating on high, and the vents must be open and...

49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

Code of Federal Regulations, 2012 CFR

2012-10-01

... normal operating temperature. (5) The heating, ventilation and air conditioning (HVAC) system or a dedicated heating or air conditioner system must be operating on high, and the vents must be open and...

49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

Code of Federal Regulations, 2011 CFR

2011-10-01

... normal operating temperature. (5) The heating, ventilation and air conditioning (HVAC) system or a dedicated heating or air conditioner system must be operating on high, and the vents must be open and...

Acute Oral Toxicity Up-And-Down-Procedure

EPA Pesticide Factsheets

The Up-and-Down Procedure is an alternative acute toxicity test that provides a way to determine the toxicity of chemicals with fewer test animals by using sequential dosing steps. Find out about this test procedure.

Sediment Toxicity Testing

EPA Science Inventory

Sediment toxicity testing has become a fundamental component of regulatory frameworks for assessing the risks posed by contaminated sediments and for development of chemical sediment quality guidelines. Over the past two decades, sediment toxicity testing methods have advanced co...

Toxicity Estimation Software Tool (TEST)

EPA Science Inventory

The Toxicity Estimation Software Tool (TEST) was developed to allow users to easily estimate the toxicity of chemicals using Quantitative Structure Activity Relationships (QSARs) methodologies. QSARs are mathematical models used to predict measures of toxicity from the physical c...

Rice seed toxicity tests for organic and inorganic substances

USGS Publications Warehouse

Wang, W.

1994-01-01

Plant seed toxicity tests can be used to evaluate hazardous waste sites and to assess toxicity of complex effluents and industrial chemicals. Conventional plant seed toxicity tests are performed using culture dishes containing filter paper. Some reports indicate that filter papers might interfere with the toxicity of inorganic substances. In this study, a plastic seed tray was used. Rice was used as the test species. A comparison of results in the literature and this study revealed that variation of test species, methods, exposure duration, and other factors may affect the test results. The results of this study showed that the order of decreasing toxicity of metal ions was Cu>Ag>Ni>Cd>Cr(VI)>Pb>Zn>Mn>NaF for rice. The test results were similar to those reported in the literature for lettuce Ag>Ni>Cd,Cu>Cr (VI)>Zn>Mn, millet Cu,Ni>Cd>Cr(VI)>Zn>Mn, and ryegrass Cu>Ni>Mn>>Pb>Cd>Zn> Al>Hg>Cr>Fe. The order of decreasing toxicity of organic herbicides was paraquat, 2,4-D>>glyphosate>bromacil.

An empirical comparison of a dynamic software testability metric to static cyclomatic complexity

NASA Technical Reports Server (NTRS)

Voas, Jeffrey M.; Miller, Keith W.; Payne, Jeffrey E.

1993-01-01

This paper compares the dynamic testability prediction technique termed 'sensitivity analysis' to the static testability technique termed cyclomatic complexity. The application that we chose in this empirical study is a CASE generated version of a B-737 autoland system. For the B-737 system we analyzed, we isolated those functions that we predict are more prone to hide errors during system/reliability testing. We also analyzed the code with several other well-known static metrics. This paper compares and contrasts the results of sensitivity analysis to the results of the static metrics.

Fatigue of notched fiber composite laminates. Part 2: Analytical and experimental evaluation

NASA Technical Reports Server (NTRS)

Kulkarni, S. V.; Mclaughlin, P. V., Jr.; Pipes, R. B.

1976-01-01

The analytical/experimental correlation study was performed to develop an understanding of the behavior of notched Boron/epoxy laminates subjected to tension/tension fatigue loading. It is postulated that the fatigue induced property changes (stiffness as well as strength) of the laminate can be obtained from the lamina fatigue properties. To that end, the Boron/epoxy lamina static and fatigue data (lifetime, residual stiffness and strength) were obtained initially. The longitudinal and transverse tension data were determined from the (0) and (90) laminate tests while the in-plane shear data were obtained from the (+ or - 45) sub s laminates. The static tests obtained the notched strength and mode of failure while the fatigue tests determined lifetime, damage propagation and residual strength. The failure in static tension occurred in a transverse crack propagation mode.

Construct validity of functional capacity tests in healthy workers

PubMed Central

2013-01-01

Background Functional Capacity (FC) is a multidimensional construct within the activity domain of the International Classification of Functioning, Disability and Health framework (ICF). Functional capacity evaluations (FCEs) are assessments of work-related FC. The extent to which these work-related FC tests are associated to bio-, psycho-, or social factors is unknown. The aims of this study were to test relationships between FC tests and other ICF factors in a sample of healthy workers, and to determine the amount of statistical variance in FC tests that can be explained by these factors. Methods A cross sectional study. The sample was comprised of 403 healthy workers who completed material handling FC tests (lifting low, overhead lifting, and carrying) and static work FC tests (overhead working and standing forward bend). The explainable variables were; six muscle strength tests; aerobic capacity test; and questionnaires regarding personal factors (age, gender, body height, body weight, and education), psychological factors (mental health, vitality, and general health perceptions), and social factors (perception of work, physical workloads, sport-, leisure time-, and work-index). A priori construct validity hypotheses were formulated and analyzed by means of correlation coefficients and regression analyses. Results Moderate correlations were detected between material handling FC tests and muscle strength, gender, body weight, and body height. As for static work FC tests; overhead working correlated fair with aerobic capacity and handgrip strength, and low with the sport-index and perception of work. For standing forward bend FC test, all hypotheses were rejected. The regression model revealed that 61% to 62% of material handling FC tests were explained by physical factors. Five to 15% of static work FC tests were explained by physical and social factors. Conclusions The current study revealed that, in a sample of healthy workers, material handling FC tests were related to physical factors but not to the psychosocial factors measured in this study. The construct of static work FC tests remained largely unexplained. PMID:23758870

40 CFR 797.1600 - Fish early life stage toxicity test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the test solution concentrations. The test terminates following 60 days of post-hatch exposure (for an... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Fish early life stage toxicity test... Fish early life stage toxicity test. (a) Purpose. This guideline is intended to be used for assessing...

40 CFR 797.1600 - Fish early life stage toxicity test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the test solution concentrations. The test terminates following 60 days of post-hatch exposure (for an... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Fish early life stage toxicity test... Fish early life stage toxicity test. (a) Purpose. This guideline is intended to be used for assessing...

Can interpreting sediment toxicity tests a mega sites benefit from novel approaches to normalization to address batching of tests?

EPA Science Inventory

Sediment toxicity tests are a key tool used in Ecological Risk Assessments for contaminated sediment sites. Interpreting test results and defining toxicity is often a challenge. This is particularly true at mega sites where the testing regime is large, and by necessity performed ...

Matching novel face and voice identity using static and dynamic facial images.

PubMed

Smith, Harriet M J; Dunn, Andrew K; Baguley, Thom; Stacey, Paula C

2016-04-01

Research investigating whether faces and voices share common source identity information has offered contradictory results. Accurate face-voice matching is consistently above chance when the facial stimuli are dynamic, but not when the facial stimuli are static. We tested whether procedural differences might help to account for the previous inconsistencies. In Experiment 1, participants completed a sequential two-alternative forced choice matching task. They either heard a voice and then saw two faces or saw a face and then heard two voices. Face-voice matching was above chance when the facial stimuli were dynamic and articulating, but not when they were static. In Experiment 2, we tested whether matching was more accurate when faces and voices were presented simultaneously. The participants saw two face-voice combinations, presented one after the other. They had to decide which combination was the same identity. As in Experiment 1, only dynamic face-voice matching was above chance. In Experiment 3, participants heard a voice and then saw two static faces presented simultaneously. With this procedure, static face-voice matching was above chance. The overall results, analyzed using multilevel modeling, showed that voices and dynamic articulating faces, as well as voices and static faces, share concordant source identity information. It seems, therefore, that above-chance static face-voice matching is sensitive to the experimental procedure employed. In addition, the inconsistencies in previous research might depend on the specific stimulus sets used; our multilevel modeling analyses show that some people look and sound more similar than others.

Level of functional capacities following soccer-specific warm-up methods among elite collegiate soccer players.

PubMed

Vazini Taher, Amir; Parnow, Abdolhossein

2017-05-01

Different methods of warm-up may have implications in improving various aspects of soccer performance. The present study aimed to investigate acute effects of soccer specific warm-up protocols on functional performance tests. This study using randomized within-subject design, investigated the performance of 22 collegiate elite soccer player following soccer specific warm-ups using dynamic stretching, static stretching, and FIFA 11+ program. Post warm-up examinations consisted: 1) Illinois Agility Test; 2) vertical jump; 3) 30 meter sprint; 4) consecutive turns; 5) flexibility of knee. Vertical jump performance was significantly lower following static stretching, as compared to dynamic stretching (P=0.005). Sprint performance declined significantly following static stretching as compared to FIFA 11+ (P=0.023). Agility time was significantly faster following dynamic stretching as compared to FIFA 11+ (P=0.001) and static stretching (P=0.001). Knee flexibility scores were significantly improved following the static stretching as compared to dynamic stretching (P=016). No significant difference was observed for consecutive turns between three warm-up protocol. The present finding showed that a soccer specific warm-up protocol relied on dynamic stretching is preferable in enhancing performance as compared to protocols relying on static stretches and FIFA 11+ program. Investigators suggest that while different soccer specific warm-up protocols have varied types of effects on performance, acute effects of dynamic stretching on performance in elite soccer players are assured, however application of static stretching in reducing muscle stiffness is demonstrated.

Static tests of the propulsion system. [Propfan Test Assessment program

NASA Technical Reports Server (NTRS)

Withers, C. C.; Bartel, H. W.; Turnberg, J. E.; Graber, E. J.

1987-01-01

Advanced, highly-loaded, high-speed propellers, called propfans, are promising to revolutionize the transport aircraft industry by offering a 15- to 30-percent fuel savings over the most advanced turbofans without sacrificing passenger comfort or violating community noise standards. NASA Lewis Research Center and industry have been working jointly to develop the needed propfan technology. The NASA-funded Propfan Test Assessment (PTA) Program represents a key element of this joint program. In PTA, Lockheed-Georgia, working in concert with Hamilton Standard, Rohr Industries, Gulfstream Aerospace, and Allison, is developing a propfan propulsion system which will be mounted on the left wing of a modified Gulfstream GII aircraft and flight tested to verify the in-flight characteristics of a 9-foot diameter, single-rotation propfan. The propfan, called SR-7L, was designed and fabricated by Hamilton Standard under a separate NASA contract. Prior to flight testing, the PTA propulsion system was static tested at the Rohr Brown Field facility. In this test, propulsion system operational capability was verified and data was obtained on propfan structural response, system acoustic characteristics, and system performance. This paper reports on the results of the static tests.

Tracking pyrethroid toxicity in surface water samples: Exposure dynamics and toxicity identification tools for laboratory tests with Hyalella azteca (Amphipoda).

PubMed

Deanovic, Linda A; Stillway, Marie; Hammock, Bruce G; Fong, Stephanie; Werner, Inge

2018-02-01

Pyrethroid insecticides are commonly used in pest control and are present at toxic concentrations in surface waters of agricultural and urban areas worldwide. Monitoring is challenging as a result of their high hydrophobicity and low toxicity thresholds, which often fall below the analytical methods detection limits (MDLs). Standard daphnid bioassays used in surface water monitoring are not sensitive enough to protect more susceptible invertebrate species such as the amphipod Hyalella azteca and chemical loss during toxicity testing is of concern. In the present study, we quantified toxicity loss during storage and testing, using both natural and synthetic water, and presented a tool to enhance toxic signal strength for improved sensitivity of H. azteca toxicity tests. The average half-life during storage in low-density polyethylene (LDPE) cubitainers (Fisher Scientific) at 4 °C of 5 pyrethroids (permethrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, and esfenvalerate) and one organophosphate (chlorpyrifos; used as reference) was 1.4 d, and piperonyl butoxide (PBO) proved an effective tool to potentiate toxicity. We conclude that toxicity tests on ambient water samples containing these hydrophobic insecticides are likely to underestimate toxicity present in the field, and mimic short pulse rather than continuous exposures. Where these chemicals are of concern, the addition of PBO during testing can yield valuable information on their presence or absence. Environ Toxicol Chem 2018;37:462-472. © 2017 SETAC. © 2017 SETAC.

Description of a Pressure Measurement Technique for Obtaining Surface Static Pressures of a Radial Turbine

NASA Technical Reports Server (NTRS)

Dicicco, L. Danielle; Nowlin, Brent C.; Tirres, Lizet

1992-01-01

The aerodynamic performance of a solid uncooled version of a cooled radial turbine was evaluated in the Small Engine Components Test Facility Turbine rig at the NASA Lewis Research Center. Specifically, an experiment was conducted to rotor surface static pressures. This was the first time surface static pressures had been measured on a radial turbine at NASA Lewis. These pressures were measured by a modified Rotating Data Package (RDP), a standard product manufactured by Scanivalve, Inc. Described here are the RDP, and the modifications that were made, as well as the checkout, installation, and testing procedures. The data presented are compared to analytical results obtained from NASA's MERIDL TSONIC BLAYER (MTSB) code.

Description of a pressure measurement technique for obtaining surface static pressures of a radial turbine

NASA Technical Reports Server (NTRS)

Dicicco, L. D.; Nowlin, Brent C.; Tirres, Lizet

1992-01-01

The aerodynamic performance of a solid uncooled version of a cooled radial turbine was evaluated in the Small Engine Components Test Facility Turbine rig at the NASA Lewis Research Center. Specifically, an experiment was conducted to rotor surface static pressures. This was the first time surface static pressures had been measured on a radial turbine at NASA Lewis. These pressures were measured by a modified Rotating Data Package (RDP), a standard product manufactured by Scanivalve, Inc. Described here are the RDP, and the modifications that were made, as well as the checkout, installation, and testing procedures. The data presented are compared to analytical results obtained from NASA's MERIDL TSONIC BLAYER (MTSB) code.

Kinect-based sign language recognition of static and dynamic hand movements

NASA Astrophysics Data System (ADS)

Dalawis, Rando C.; Olayao, Kenneth Deniel R.; Ramos, Evan Geoffrey I.; Samonte, Mary Jane C.

2017-02-01

A different approach of sign language recognition of static and dynamic hand movements was developed in this study using normalized correlation algorithm. The goal of this research was to translate fingerspelling sign language into text using MATLAB and Microsoft Kinect. Digital input image captured by Kinect devices are matched from template samples stored in a database. This Human Computer Interaction (HCI) prototype was developed to help people with communication disability to express their thoughts with ease. Frame segmentation and feature extraction was used to give meaning to the captured images. Sequential and random testing was used to test both static and dynamic fingerspelling gestures. The researchers explained some factors they encountered causing some misclassification of signs.

Large Deformation Dynamic Bending of Composite Beams

NASA Technical Reports Server (NTRS)

Derian, E. J.; Hyer, M. W.

1986-01-01

Studies were conducted on the large deformation response of composite beams subjected to a dynamic axial load. The beams were loaded with a moderate eccentricity to promote bending. The study was primarily experimental but some finite element results were obtained. Both the deformation and the failure of the beams were of interest. The static response of the beams was also studied to determine potential differences between the static and dynamic failure. Twelve different laminate types were tested. The beams tested were 23 in. by 2 in. and generally 30 plies thick. The beams were loaded dynamically with a gravity-driven impactor traveling at 19.6 ft/sec and quasi-static tests were conducted on identical beams in a displacement controlled manner. For laminates of practical interest, the failure modes under static and dynamic loadings were identical. Failure in most of the laminate types occurred in a single event involving 40% to 50% of the plies. However, failure in laminates with 300 or 150 off-axis plies occurred in several events. All laminates exhibited bimodular elastic properties. The compressive flexural moduli in some laminates was measured to be 1/2 the tensile flexural modulus. No simple relationship could be found among the measured ultimate failure strains of the different laminate types. Using empirically determined flexural properties, a finite element analysis was reasonably accurate in predicting the static and dynamic deformation response.

40 CFR 799.5085 - Chemical testing requirements for first group of high production volume chemicals (HPV1).

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Toxicity to Plants (Algae): ASTM E 1218 Test Group 2 for C1: 1. Chronic Toxicity to Daphnia: ASTM E 1193 2. Toxicity to Plants (Algae): ASTM E 1218 The following are the special conditions for C1, C2, C3, C4, C5.... Acute Toxicity to Daphnia: ASTM E 729 2. Toxicity to Plants (Algae): ASTM E 1218 Test Group 2 for C2: 1...

A novel continuous toxicity test system using a luminously modified freshwater bacterium.

PubMed

Cho, Jang-Cheon; Park, Kyung-Je; Ihm, Hyuk-Soon; Park, Ji-Eun; Kim, Se-Young; Kang, Ilnam; Lee, Kyu-Ho; Jahng, Deokjin; Lee, Dong-Hun; Kim, Sang-Jong

2004-09-15

An automated continuous toxicity test system was developed using a recombinant bioluminescent freshwater bacterium. The groundwater-borne bacterium, Janthinobacterium lividum YH9-RC, was modified with luxAB and optimized for toxicity tests using different kinds of organic carbon compounds and heavy metals. luxAB-marked YH9-RC cells were much more sensitive (average 7.3-8.6 times) to chemicals used for toxicity detection than marine Vibrio fischeri cells used in the Microtox assay. Toxicity tests for wastewater samples using the YH9-RC-based toxicity assay showed that EC50-5 min values in an untreated raw wastewater sample (23.9 +/- 12.8%) were the lowest, while those in an effluent sample (76.7 +/- 14.9%) were the highest. Lyophilization conditions were optimized in 384-multiwell plates containing bioluminescent bacteria that were pre-incubated for 15 min in 0.16 M of trehalose prior to freeze-drying, increasing the recovery of bioluminescence and viability by 50%. Luminously modified cells exposed to continuous phenol or wastewater stream showed a rapid decrease in bioluminescence, which fell below detectable range within 1 min. An advanced toxicity test system, featuring automated real-time toxicity monitoring and alerting functions, was designed and finely tuned. This novel continuous toxicity test system can be used for real-time biomonitoring of water toxicity, and can potentially be used as a biological early warning system.

NARC Rayon Replacement Program for the RSRM Nozzle, Phase IV Qualification and Implementation Status

NASA Technical Reports Server (NTRS)

Haddock, M. Reed; Wendel, Gary M.; Cook, Roger V.

2005-01-01

The Space Shuttle NARC Rayon Replacement Program has down-selected Enka rayon as a replacement for the obsolete NARC rayon in the nozzle carbon cloth phenolic (CCP) ablative insulators. Full qualification testing of the Enka rayon-based carbon cloth phenolic is underway, including processing, thmal/structural properties, and hot-fire subscale tests. Required thermal-structural capabilities, together with confidence in erosio/char performance in simulated and subscale hot fire tests such as Wright-Patterson Air Force Base Laser Hardened Materials Evaluation Laboratory testing, NASA-MSFC 24-inch motor tests, NASA-MSFC Solid Fuel Torch - Super Sonic Blast Tube, NASA-MSFC Plasma Torch Test Bed, ATK Thiokol Forty Pound Charge and NASA-MSFC MNASA justified the testing of the new Enka-rayon candidate on full-scale static test motors. The first RSRM full-scale static test motor nozzle, fabricated using the new Enka rayon-based CCP, was successfully demonstrated in June 2004. Two additional static test motors are planned with the new Enka rayon in the next two years along with additional A-basis property characterization. Process variation or "corner-of-the-box" testing together with cured and uncured aging studies are also planned as some of the pre-flight implementation activities with 5-year cured aging studies over-lapping flight hardware fabrication.

A comparison of sediment toxicity test methods at three Great Lake Areas of Concern

USGS Publications Warehouse

Burton, G. Allen; Ingersoll, Christopher G.; Burnett, LouAnn C.; Henry, Mary; Hinman, Mark L.; Klaine, Stephen J.; Landrum, Peter F.; Ross, Phillipe; Tuchman, Marc

1996-01-01

The significance of sediment contamination is often evaluated using sediment toxicity (bioassay) testing. There are relatively few “standardized” test methods for evaluating sediments. Popular sediment toxicity methods examine the extractable water (elutriate), interstitial water, or whole (bulk) sediment phases using test species spanning the aquatic food chain from bacteria to fish. The current study was designed to evaluate which toxicity tests were most useful in evaluations of sediment contamination at three Great Lake Areas of Concern. Responses of 24 different organisms including fish, mayflies, amphipods, midges, cladocerans, rotifers, macrophytes, algae, and bacteria were compared using whole sediment or elutriate toxicity assays. Sediments from several sites in the Buffalo River, Calumet River (Indiana Harbor), and Saginaw River were tested, as part of the U.S. Environmental Protection Agency's (USEPA) Assessment and Remediation of Contaminated Sediments (ARCS) Project. Results indicated several assays to be sensitive to sediment toxicity and able to discriminate between differing levels of toxicity. Many of the assay responses were significantly correlated to other toxicity responses and were similar based on factor analysis. For most applications, a test design consisting of two to three assays should adequately detect sediment toxicity, consisting of various groupings of the following species: Hyalella azteca, Ceriodaphnia dubia, Chironomus riparius, Chironomus tentans, Daphnia magna, Pimephales promelas, Hexagenia bilineata, Diporeia sp., Hydrilla verticillata, or Lemna minor.

PH DEPENDENT TOXICITY OF FIVE METALS TO THREE MARINE ORGANISMS

EPA Science Inventory

The pH of natural marine systems is relatively stable; this may explain why metal toxicity changes with pH have not been well documented. However, changes in metal toxicity with pH in marine waters are of concern in toxicity testing. During porewater toxicity testing pH can chang...