WorldWideScience

Sample records for laboratory microcosm experiment

  1. Molecular analysis of microbial community structures in pristine and contaminated aquifers--Field and laboratory microcosm experiments

    Science.gov (United States)

    Shi, Y.; Zwolinski, M.D.; Schreiber, M.E.; Bahr, J.M.; Sewell, G.W.; Hickey, W.J.

    1999-01-01

    Molecular Analysis of Microbial Community Structures in Pristine and Contaminated Aquifers: Field and Laboratory Microcosm Experimentsvar callbackToken='531E8ACDB6C8511'; var subCode='asmjournal_sub'; var OAS_sitepage = 'aem.asm.org'; This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminated (NC) and (ii) examine alterations in microbial community structures resulting from exposure to toluene and/or electron acceptor supplementation (nitrate). The latter objective was addressed by using the NC and FC aquifer materials for anaerobic microcosm studies in which phylogenetic probe analysis was complemented by microbial activity assays. Domain probe analysis of the aquifer samples showed that the communities were predominantlyBacteria; Eucarya and Archaea were not detectable. At the phylum and subclass levels, the FC and NC aquifer material had similar relative abundance distributions of 43 to 65% β- and γ-Proteobacteria (B+G), 31 to 35% α-Proteobacteria (ALF), 15 to 18% sulfate-reducing bacteria, and 5 to 10% high G+C gram positive bacteria. Compared to that of the NC region, the community structure of the FC material differed mainly in an increased abundance of B+G relative to that of ALF. The microcosm communities were like those of the field samples in that they were predominantly Bacteria (83 to 101%) and lacked detectable Archaea but differed in that a small fraction (2 to 8%) of Eucarya was detected regardless of the treatment applied. The latter result was hypothesized to reflect enrichment of anaerobic protozoa. Addition of nitrate and/or toluene stimulated microbial activity in the microcosms, but only supplementation of toluene alone significantly altered community structures. For the NC material, the dominant subclass shifted from B+G to ALF, while in the FC microcosms 55 to 65

  2. Comparing the impacts of sediment-bound bifenthrin on aquatic macroinvertebrates in laboratory bioassays and field microcosms.

    Science.gov (United States)

    Boyle, Rhianna L; Hoak, Molly N; Pettigrove, Vincent J; Hoffmann, Ary A; Long, Sara M

    2016-11-01

    We conducted two laboratory bioassays and two field microcosm exposures with bifenthrin (a synthetic pyrethroid) in order to evaluate the capacity of single-species laboratory bioassays to predict lethal and sublethal impacts on aquatic invertebrates in microcosms. For the laboratory species, Chironomus tepperi, larval survival was reduced by 24% at 53.66µg/g OC, while adult emergence was reduced at concentrations of 33.33µg/g OC and higher, with a 61% decrease at 77.78µg/g OC and no emergence at 126.67µg/g OC. The abundance of several other microcosm taxa was reduced in the microcosms at a similar concentration range (33.33µg/g OC and above), however there was no impact on the abundance of the congeneric species, Chironomus oppositus. The differences in impacts between test systems were potentially due to both differing species sensitivity and the interaction of ambient temperature with bifenthrin toxicity. Bifenthrin also was associated with early emergence of Chironomus sp. in both test systems, at concentrations of 10µg/g OC and higher (laboratory) and 43.90µg/g OC (microcosm), and with a significant decrease in the proportion of C. oppositus males in a microcosm. These findings indicate that while laboratory bioassays accurately predict many impacts in the field, there are some limitations to the predictive capacity of these tests. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. An automated image analysis system to measure and count organisms in laboratory microcosms.

    Directory of Open Access Journals (Sweden)

    François Mallard

    Full Text Available 1. Because of recent technological improvements in the way computer and digital camera perform, the potential use of imaging for contributing to the study of communities, populations or individuals in laboratory microcosms has risen enormously. However its limited use is due to difficulties in the automation of image analysis. 2. We present an accurate and flexible method of image analysis for detecting, counting and measuring moving particles on a fixed but heterogeneous substrate. This method has been specifically designed to follow individuals, or entire populations, in experimental laboratory microcosms. It can be used in other applications. 3. The method consists in comparing multiple pictures of the same experimental microcosm in order to generate an image of the fixed background. This background is then used to extract, measure and count the moving organisms, leaving out the fixed background and the motionless or dead individuals. 4. We provide different examples (springtails, ants, nematodes, daphnia to show that this non intrusive method is efficient at detecting organisms under a wide variety of conditions even on faintly contrasted and heterogeneous substrates. 5. The repeatability and reliability of this method has been assessed using experimental populations of the Collembola Folsomia candida. 6. We present an ImageJ plugin to automate the analysis of digital pictures of laboratory microcosms. The plugin automates the successive steps of the analysis and recursively analyses multiple sets of images, rapidly producing measurements from a large number of replicated microcosms.

  4. Atrazine remediation in wetland microcosms.

    Science.gov (United States)

    Runes, H B; Bottomley, P J; Lerch, R N; Jenkins, J J

    2001-05-01

    Laboratory wetland microcosms were used to study treatment of atrazine in irrigation runoff by a field-scale-constructed wetland under controlled conditions. Three experiments, in which 1 ppm atrazine was added to the water column of three wetland, one soil control, and one water control microcosm, were conducted. Atrazine dissipation from the water column and degradate formation (deethylatrazine [DEA]; deisopropylatrazine [DIA]; and hydroxyatrazine [HA]) were monitored. Atrazine dissipation from the water column of wetland microcosms was biphasic. Less than 12% of the atrazine applied to wetland microcosms remained in the water column on day 56. Atrazine degradates were observed in water and sediment, with HA the predominant degradate. Analysis of day 56 sediment samples indicated that a significant portion of the initial application was detected as the parent compound and HA. Most probable number (MPN) assays demonstrated that atrazine degrader populations were small in wetland sediment. Wetland microcosms were able to reduce atrazine concentration in the water column via sorption and degradation. Based on results from this study, it is hypothesized that plant uptake contributed to atrazine dissipation from the water column.

  5. Molecular Analysis of Microbial Community Structures in Pristine and Contaminated Aquifers: Field and Laboratory Microcosm Experiments

    Science.gov (United States)

    Shi, Y.; Zwolinski, M. D.; Schreiber, M. E.; Bahr, J. M.; Sewell, G. W.; Hickey, W. J.

    1999-01-01

    FC aquifer community. These studies demonstrated that alterations in aquifer microbial communities resulting from specific anthropogenic perturbances can be inferred from microcosm studies integrating chemical and phylogenetic probe analysis and in the case of hydrocarbon contamination may facilitate the identification of organisms important for in situ biodegradation processes. Further work integrating and coordinating microcosm and field experiments is needed to explore how differences in scale, substrate complexity, and other hydrogeological conditions may affect patterns observed in these systems. PMID:10224013

  6. Impact of triphenyltin acetate in microcosms simulating floodplain lakes. II. Comparison of species sensitivity distributions between laboratory and semi-field.

    Science.gov (United States)

    Roessink, I; Belgers, J D M; Crum, S J H; van den Brink, P J; Brock, T C M

    2006-07-01

    The study objectives were to shed light on the types of freshwater organism that are sensitive to triphenyltin acetate (TPT) and to compare the laboratory and microcosm sensitivities of the invertebrate community. The responses of a wide array of freshwater taxa (including invertebrates, phytoplankton and macrophytes) from acute laboratory Single Species Tests (SST) were compared with the concentration-response relationships of aquatic populations in two types of freshwater microcosms. Representatives of several taxonomic groups of invertebrates, and several phytoplankton and vascular plant species proved to be sensitive to TPT, illustrating its diverse modes of toxic action. Statistically calculated ecological risk thresholds (HC5 values) based on 96 h laboratory EC50 values for invertebrates were 1.3 microg/l, while these values on the basis of microcosm-Species Sensitivity Distributions (SSD) for invertebrates in sampling weeks 2-8 after TPT treatment ranged from 0.2 to 0.6 microg/l based on nominal peak concentrations. Responses observed in the microcosms did not differ between system types and sampling dates, indicating that ecological threshold levels are not affected by different community structures including taxa sensitive to TPT. The laboratory-derived invertebrate SSD curve was less sensitive than the curves from the microcosms. Possible explanations for the more sensitive field response are delayed effects and/or additional chronic exposure via the food chain in the microcosms.

  7. Impact of triphenyltin acetate in microcosms simulating floodplain lakes; II comparison of species sensitivity distributions between laboratory and semi-field

    OpenAIRE

    Roessink, I.; Belgers, J.D.M.; Crum, S.J.H.; Brink, van den, P.J.; Brock, T.C.M.

    2006-01-01

    The study objectives were to shed light on the types of freshwater organism that are sensitive to triphenyltin acetate (TPT) and to compare the laboratory and microcosm sensitivities of the invertebrate community. The responses of a wide array of freshwater taxa (including invertebrates, phytoplankton and macrophytes) from acute laboratory Single Species Tests (SST) were compared with the concentration¿response relationships of aquatic populations in two types of freshwater microcosms. Repres...

  8. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

    KAUST Repository

    Tsiola, A.; Pitta, P.; Fodelianakis, Stylianos; Pete, R.; Magiopoulos, I.; Mara, P.; Psarra, S.; Tanaka, T.; Mostajir, B.

    2015-01-01

    groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely

  9. Microcosm 2.011

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Microcosm, CERN's first exhibition centre, will soon be upgraded. While keeping its present character and many of its nice features, the use of new cutting-edge exhibition technologies together with an area for student experiments and physics demonstrations will make version 2.011 even more attractive to the general public and school classes.   Layout of the new Microcosm 2.011 exhibition. New Year, and a new look for Microcosm! CERN's popular exhibition centre will undergo a transformation that will see, among other things, the installation of a new area dedicated to modern physics experiments for school groups. “Microcosm will keep its main features and character,” says Rolf Landua, Head of the Education Group, which is in charge of the project. “While some parts will be replaced by more modern exhibition technologies and contemporary scenography, others will be moved to allow a better visitor flow and make room for the brand-new school lab and public demonstration...

  10. Factors Influencing TCE Anaerobic Dechlorination Investigated via Simulations of Microcosm Experiments

    Science.gov (United States)

    Mao, X.; Harkness, M.; Lee, M. D.; Mack, E. E.; Dworatzek, S.; Acheson, C.; McCarty, P.; Barry, D. A.; Gerhard, J. I.

    2006-12-01

    SABRE (Source Area BioREmediation) is a public-private consortium whose charter is to determine if enhanced anaerobic bioremediation can result in effective and quantifiable treatment of chlorinated solvent DNAPL source areas. The focus of this 4-year, $5.7 million research project is a field site in the United Kingdom containing a TCE DNAPL source area. In preparation, a microcosm study was performed to determine the optimal combination of factors to support reductive dechlorination of TCE in site soil and groundwater. The study consisted of 168 bottles distributed between four laboratories (Dupont, GE, SiREM, and Terra Systems) and tested the impact of six carbon substrates (lactate, acetate, methanol, SRS (soybean oil), hexanol, butyl acetate), bioaugmentation with KB-1 bacterial culture, three TCE levels (100 mg/L, 400 mg/L, and 800 mg/L) and two sulphate levels (200 mg/L, >500 mg/L) on TCE dechlorination. This research presents a numerical model designed to simulate the main processes occurring in the microcosms, including substrate fermentation, sequential dechlorination, toxic inhibition, and the influence of sulphate concentration. In calibrating the model to over 60 of the microcosm experiments, lumped parameters were employed to quantify the effect of key factors on the conversion rate of each chlorinated ethene in the TCE degradation sequence. Results quantify the benefit (i.e., increased stepwise dechlorination rate) due to both bioaugmentation and the presence of higher sulphate concentrations. Competitive inhibition is found to increase in significance as TCE concentrations increase; however, inclusion of Haldane inhibition is not supported. Over a wide range of experimental conditions and dechlorination steps, SRS appears to induce relatively little hydrogen limitation, thereby facilitating relatively quick conversion of TCE to ethene. In general, hydrogen limitation is found to increase with increasing TCE concentration and with bioaugmentation, and

  11. Semicontinuous microcosm study of aerobic cometabolism of trichloroethylene using toluene

    Energy Technology Data Exchange (ETDEWEB)

    Han, Y.L. [Department of Mineral and Petroleum Engineering, National Cheng Kung University, 1 University Avenue, Tainan 701, Taiwan (China); Kuo, M.C. Tom [Department of Mineral and Petroleum Engineering, National Cheng Kung University, 1 University Avenue, Tainan 701, Taiwan (China)], E-mail: mctkuobe@mail.ncku.edu.tw; Tseng, I.C. [Department of Life Sciences, National Cheng Kung University, 1 University Avenue, Tainan 701, Taiwan (China); Lu, C.J. [Department of Environmental Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China)

    2007-09-30

    A semicontinuous slurry-microcosm method was applied to mimic trichloroethylene (TCE) cometabolic biodegradation field results at the Que-Jen in-situ pilot study. The microcosm study confirmed the process of aerobic cometabolism of TCE using toluene as the primary substrate. Based on the nucleotide sequence of 16S rRNA genes, the toluene-oxidizing bacteria in microcosms were identified, i.e. Ralstonia sp. P-10 and Pseudomonasputida. The first-order constant of TCE-degradation rate was 0.5 day{sup -1} for both Ralstonia sp. P-10 and P.putida. The TCE cometabolic-biodegradation efficiency measured from the slurry microcosms was 46%, which appeared pessimistic compared to over 90% observed from the in-situ pilot study. The difference in the TCE cometabolic-biodegradation efficiency was likely due to the reactor configurations and the effective time duration of toluene presence in laboratory microcosms (1 days) versus in-situ pilot study (3 days). The results of microcosm experiments using different toluene-injection schedules supported the hypothesis. With a given amount of toluene injection, it is recommended to maximize the effective time duration of toluene presence in reactor design for TCE cometabolic degradation.

  12. Semicontinuous microcosm study of aerobic cometabolism of trichloroethylene using toluene

    International Nuclear Information System (INIS)

    Han, Y.L.; Kuo, M.C. Tom; Tseng, I.C.; Lu, C.J.

    2007-01-01

    A semicontinuous slurry-microcosm method was applied to mimic trichloroethylene (TCE) cometabolic biodegradation field results at the Que-Jen in-situ pilot study. The microcosm study confirmed the process of aerobic cometabolism of TCE using toluene as the primary substrate. Based on the nucleotide sequence of 16S rRNA genes, the toluene-oxidizing bacteria in microcosms were identified, i.e. Ralstonia sp. P-10 and Pseudomonasputida. The first-order constant of TCE-degradation rate was 0.5 day -1 for both Ralstonia sp. P-10 and P.putida. The TCE cometabolic-biodegradation efficiency measured from the slurry microcosms was 46%, which appeared pessimistic compared to over 90% observed from the in-situ pilot study. The difference in the TCE cometabolic-biodegradation efficiency was likely due to the reactor configurations and the effective time duration of toluene presence in laboratory microcosms (1 days) versus in-situ pilot study (3 days). The results of microcosm experiments using different toluene-injection schedules supported the hypothesis. With a given amount of toluene injection, it is recommended to maximize the effective time duration of toluene presence in reactor design for TCE cometabolic degradation

  13. Assessment of MTBE biodegradation in contaminated groundwater using 13C and 14C analysis: Field and laboratory microcosm studies

    International Nuclear Information System (INIS)

    Thornton, Steven F.; Bottrell, Simon H.; Spence, Keith H.; Pickup, Roger; Spence, Michael J.; Shah, Nadeem; Mallinson, Helen E.H.; Richnow, Hans H.

    2011-01-01

    Highlights: → Carbon isotope fractionation for MTBE varies with dissolved oxygen concentration. → Carbon isotope fractionation can underestimate MTBE biodegradation at plume fringes. → Fractionation factors must be for specific biodegradation mechanisms and conditions. → Specific microbial populations influence carbon isotope fractionation in groundwater. - Abstract: Radiolabelled assays and compound-specific stable isotope analysis (CSIA) were used to assess methyl tert-butyl ether (MTBE) biodegradation in an unleaded fuel plume in a UK chalk aquifer, both in the field and in laboratory microcosm experiments. The 14 C-MTBE radiorespirometry studies demonstrated widespread potential for aerobic and anaerobic MTBE biodegradation in the aquifer. However, δ 13 C compositions of MTBE in groundwater samples from the plume showed no significant 13 C enrichment that would indicate MTBE biodegradation at the field scale. Carbon isotope enrichment during MTBE biodegradation was assessed in the microcosms when dissolved O 2 was not limiting, compared with low in situ concentrations (2 mg/L) in the aquifer, and in the absence of O 2 . The microcosm experiments showed ubiquitous potential for aerobic MTBE biodegradation in the aquifer within hundreds of days. Aerobic MTBE biodegradation in the microcosms produced an enrichment of 7 per mille in the MTBE δ 13 C composition and an isotope enrichment factor (ε) of -1.53 per mille when dissolved O 2 was not limiting. However, for the low dissolved O 2 concentration of up to 2 mg/L that characterizes most of the MTBE plume fringe, aerobic MTBE biodegradation produced an enrichment of 0.5-0.7 per mille, corresponding to an ε value of -0.22 per mille to -0.24 per mille. No anaerobic MTBE biodegradation occurred under these experimental conditions. These results suggest the existence of a complex MTBE-biodegrading community in the aquifer, which may consist of different aerobic species competing for MTBE and dissolved O 2

  14. Microcosm: Mysteries of the Universe and of computing

    CERN Multimedia

    2003-01-01

    In the first week of December, two new exhibitions open in Microcosm: "Mysteries of the Universe" and "Computing@CERN". Ever wondered why the Universe is habitable? How many dimensions there are? Or indeed, where matter comes from? In Microcosm's new "Mysteries of the Universe" exhibition 20 CERN researchers reveal the question that intrigues them the most and why they find the search for answers so fascinating. The exhibition consists of 20 stories, told by the researchers themselves in one of 4 languages (English, French, German or Italian). Through their tales, the visitor can discover the essence of CERN - a curiosity to understand the mechanisms of a universe full of surprises, where many fundamental questions remain unresolved. With their diverse nationalities and experience, the participants reveal not only the variety of physics research underway at CERN, but also the experiments yet to come and indeed an element of the international collaboration so essential to the laboratory. In the words of on...

  15. Impact of triphenyltin acetate in microcosms simulating floodplain lakes; II comparison of species sensitivity distributions between laboratory and semi-field

    NARCIS (Netherlands)

    Roessink, I.; Belgers, J.D.M.; Crum, S.J.H.; Brink, van den P.J.; Brock, T.C.M.

    2006-01-01

    The study objectives were to shed light on the types of freshwater organism that are sensitive to triphenyltin acetate (TPT) and to compare the laboratory and microcosm sensitivities of the invertebrate community. The responses of a wide array of freshwater taxa (including invertebrates,

  16. Impact of imidaclorprid on live-cycle development of Coccinella septempunctata in laborratory microcosms

    NARCIS (Netherlands)

    Caihong, Yu; Ronghua, Lin; Maoran, Fu; Yanming, Zhou; Brock, T.C.M.

    2014-01-01

    Long-term effects of a single application of imidacloprid on ladybird beetle, Coccinella septempunctata L., were studied in indoor laboratory microcosms, starting with the 2nd instar larvae of C. septempunctata but covering the full life cycle. The microcosms comprised enclosures containing a pot

  17. Impacts of earthworm, .i.Pheretima (Amynthas) cornosa./i. on nutrient loss from soil in microcosm experiment

    Czech Academy of Sciences Publication Activity Database

    Kaneda, Satoshi; Nakajima, M.; Murakami, T.; Urashima, Y.

    2008-01-01

    Roč. 10, - (2008) ISSN 1029-7006. [EGU General Assembly 2008. 13.04.2008-18.04.2008, Vienna] Institutional research plan: CEZ:AV0Z60660521 Keywords : Pheretima (Amynthas) cornosa * nutrient loss from soil * microcosm experiment Subject RIV: EH - Ecology, Behaviour

  18. Uncovering stability mechanisms in microbial ecosystems - combining microcosm experiments, computational modelling and ecological theory in a multidisciplinary approach

    Science.gov (United States)

    Worrich, Anja; König, Sara; Banitz, Thomas; Centler, Florian; Frank, Karin; Kästner, Matthias; Miltner, Anja; Thullner, Martin; Wick, Lukas

    2015-04-01

    Although bacterial degraders in soil are commonly exposed to fluctuating environmental conditions, the functional performance of the biodegradation processes can often be maintained by resistance and resilience mechanisms. However, there is still a gap in the mechanistic understanding of key factors contributing to the stability of such an ecosystem service. Therefore we developed an integrated approach combining microcosm experiments, simulation models and ecological theory to directly make use of the strengths of these disciplines. In a continuous interplay process, data, hypotheses, and central questions are exchanged between disciplines to initiate new experiments and models to ultimately identify buffer mechanisms and factors providing functional stability. We focus on drying and rewetting-cycles in soil ecosystems, which are a major abiotic driver for bacterial activity. Functional recovery of the system was found to depend on different spatial processes in the computational model. In particular, bacterial motility is a prerequisite for biodegradation if either bacteria or substrate are heterogeneously distributed. Hence, laboratory experiments focussing on bacterial dispersal processes were conducted and confirmed this finding also for functional resistance. Obtained results will be incorporated into the model in the next step. Overall, the combination of computational modelling and laboratory experiments identified spatial processes as the main driving force for functional stability in the considered system, and has proved a powerful methodological approach.

  19. Effects of sediment-spiked lufenuron on benthic macroinvertebrates in outdoor microcosms and single-species toxicity tests

    Energy Technology Data Exchange (ETDEWEB)

    Brock, T.C.M., E-mail: theo.brock@wur.nl [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Bas, D.A. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Belgers, J.D.M. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Bibbe, L. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Boerwinkel, M-C.; Crum, S.J.H. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Diepens, N.J. [Department of Aquatic Ecology and Water Quality Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen (Netherlands); Kraak, M.H.S.; Vonk, J.A. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Roessink, I. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands)

    2016-08-15

    Highlights: • In outdoor microcosms constructed with lufenuron-spiked sediment we observed that this insecticide persistent in the sediment compartment. • Sediment exposure to lufenuron caused population-level declines (insects and crustaceans) and increases (mainly oligochaete worms) of benthic invertebrates. • The direct and indirect effects observed in the microcosms were supported by results of sediment-spiked single species tests with Chironomus riparius, Hyalella azteca and Lumbriculus variegatus. • The tier-1 effect assessment procedure for sediment organisms recommended by the European Food Safety Authority is protective for the treatment-related responses observed in the microcosm test. - Abstract: Sediment ecotoxicity studies were conducted with lufenuron to (i) complement the results of a water-spiked mesocosm experiment with this lipophilic benzoylurea insecticide, (ii) to explore the predictive value of laboratory single-species tests for population and community-level responses of benthic macroinvertebrates, and (iii) to calibrate the tier-1 effect assessment procedure for sediment organisms. For this purpose the concentration-response relationships for macroinvertebrates between sediment-spiked microcosms and those of 28-d sediment-spiked single-species toxicity tests with Chironomus riparius, Hyalella azteca and Lumbriculus variegatus were compared. Lufenuron persisted in the sediment of the microcosms. On average, 87.7% of the initial lufenuron concentration could still be detected in the sediment after 12 weeks. Overall, benthic insects and crustaceans showed treatment-related declines and oligochaetes treatment-related increases. The lowest population-level NOEC in the microcosms was 0.79 μg lufenuron/g organic carbon in dry sediment (μg a.s./g OC) for Tanytarsini, Chironomini and Dero sp. Multivariate analysis of the responses of benthic macroinvertebrates revealed a community-level NOEC of 0.79 μg a.s./g OC. The treatment

  20. Behind the scenes at Microcosm

    CERN Document Server

    Emma Sanders

    2015-01-01

    Works advance at Microcosm in preparation for a progressive opening of the new exhibitions from mid-July onwards.   Construction of the section on the LHC experiments (mid-June 2015).   The Microcosm exhibition space is undergoing a total revamp and will feature many new objects. Old favourites, such as the LHC tunnel model and the Linac module, will be brought up to date with more modern exhibition techniques. Another main thrust of the new exhibitions will be the focus on the people that make CERN work. This is both to show the huge diversity of expertise needed at CERN and also to help students envisage where a career in physics or engineering might take them. With the project getting the go-ahead last autumn and the closure of the Globe for building works starting from May this year, the new Microcosm exhibition areas will open progressively as and when installations are completed to ensure that summer visitors who haven’t booked a guided tour will have something to ...

  1. Incorporating detrital conditioning in outdoor microcosms dosed with JP-8 jet fuel

    International Nuclear Information System (INIS)

    Matthews, R.A.; Markiewicz, A.; Harter, V.; Landis, W.G.

    1995-01-01

    The authors have developed an outdoor microcosm system that incorporates detrital conditioning to test the hypothesis that microbiota play a critical role in altering the community response to hydrocarbon toxicants. The microcosms were constructed using 568 L tanks, arranged in 6 units of 4 tanks, with each unit equidistant from a central conditions tank (CT). During pre-treatment, the microcosms and CT were filled with nutrient-amended well water, artificial sediment, leaf packs containing dried maple leaves, elodea fragment, and unglazed tiles for periphyton growth. Water circulation was maintained at the rate of 24 exchanges per day. After four weeks, invertebrates from local ponds were added to the CT. Leafpacks were added to the CT and microcosms every two weeks; eight week old packs were discarded after returning invertebrates to the CT. On a weekly basis, 25% of the sediments, leaf packs, tiles, and elodea from each microcosms were transferred to another microcosm; the CT walls and tiles were scraped; an the water quality was monitored. Circulation was discontinued one week prior to dosing. On 4/12/96, the microcosms were dosed to contain 0--0.25 microg/L of JP-8 jet fuel. Within two weeks the GC/MS hydrocarbon concentrations were very low in the water column of the highest treatment group. There has been little acute toxicity, despite selecting doses that caused severe, acute toxicity in laboratory microcosm studies. The presence of a complex, detritus-based microbial community appears to mitigate the influences of the toxicant on the microcosms

  2. Photowalk Exhibition opens at Microcosm

    CERN Document Server

    Katarina Anthony

    2011-01-01

    The winning photographs from the 2010 Global Particle Physics Photowalk competition will go on display at Microcosm from 11 February to 2 April. The exhibition is part of a global photography event taking place over three continents, with Photowalk exhibitions opening simultaneously at Fermilab in the US, KEK in Japan and here at CERN.   DESY wire chamber - First place people's choice; second place global jury competition. Photographer: Hans-Peter Hildebrandt  If you were one of the 1,300 photography lovers who voted in last year’s Photowalk competition, this exhibition is your chance to see the winning entries in print. The exhibition will take place in the downstairs gallery of Microcosm, overlooking the garden. 15 photographs will be on display, with each of the laboratories that participated in Photowalk represented by their 3 winning entries. Among them will be the “people’s choice” sunburst photo of a particle detector at DESY (Photo 1), and...

  3. Long-term effects of ozone on CO2 exchange in peatland microcosms

    DEFF Research Database (Denmark)

    Haapala, JK; Mörsky, SK; Rinnan, Riikka

    2011-01-01

    Effects of elevated tropospheric ozone concentration on the CO2 exchange of peatland microcosms and the photosynthetic capacity of the dominating sedge, Eriophorum vaginatum, were studied in a four-year open-field experiment. The net ecosystem CO2 exchange and the dark respiration rate of the mic......Effects of elevated tropospheric ozone concentration on the CO2 exchange of peatland microcosms and the photosynthetic capacity of the dominating sedge, Eriophorum vaginatum, were studied in a four-year open-field experiment. The net ecosystem CO2 exchange and the dark respiration rate...... exchange of the peatland microcosms....

  4. Final Technical Report. Origins of subsurface microorganisms: Relating laboratory microcosm studies to a geologic time scale; FINAL

    International Nuclear Information System (INIS)

    Kieft, Thomas; Amy, Penny S.; Phillips, Fred M.

    1998-01-01

    This project was conducted as part of the Department of Energy's Deep Subsurface Science Program. It was part of a larger effort to determine the origins of subsurface microorganisms. Two hypotheses have been suggested for the origins of subsurface microorganisms: (1) microorganisms were deposited at the time of (or shortly after) geologic deposition of rocks and sediments (the in situ survival hypothesis), and (2) microorganisms have been transported from surface environments to subsurface rocks and sediments since the time of geologic deposition (transport hypothesis). These two hypotheses are not mutually exclusive. Depending on the geological setting, either one or both of these hypotheses may best explain microbial origins. Our project focused on the in situ survival hypothesis. We tested the hypothesis that microorganisms (individuals populations and communities) can survive long-term sequestration within subsurface sediments. Other objectives were to identify geologic conditions that favor long-term survival, identify physiological traits of microorganisms that favor long-term survival, and determine which groups of microorganisms are most likely to survive long-term sequestration in subsurface sediments. We tested this hypothesis using a combination of pure culture techniques in laboratory microcosms under controlled conditions and field experiments with buried subsurface sediments

  5. Microcosm reloaded!

    CERN Multimedia

    Stefania Pandolfi

    2015-01-01

    On 20 July, Microcosm reopened its doors to the public. CERN’s guides are already leading many enthusiastic visitors through the new attractions of the popular exhibition. More areas will reopen progressively over the coming weeks before the official inauguration this autumn.   A group of visitors is guided through the new Microcosm exhibit. After six months of extensive refurbishment work, Microcosm is back and open for public visits. As some installations are not yet up and running, CERN’s guides are there to provide visitors with additional explanations. “The two groups I guided were amazed to see real detector components before their eyes, laid out in inviting and informative displays,” says Achintya Rao, member of the CMS collaboration and a CERN guide. “The life-sized CMS mock-up and the CCC panorama are excellent locations to have in-depth conversations with enthusiastic visitors and give them a glimpse into everyday life at CERN.&...

  6. Come and play with HEAL in Microcosm!

    CERN Multimedia

    Stefania Pandolfi

    2016-01-01

    A new interactive game in Microcosm informs about hadron therapy – come and test it!   HEAL is a new interactive game currently under evaluation at Microcosm to inform visitors about hadron therapy, one aspect of the CERN-related contributions to the medical field. Microcosm is continuously evolving and new content is installed regularly. One of the most recent exhibits is called HEAL - an interactive game with the aim of informing visitors about the hadron therapy to treat cancer. It has been developed by Jenny Rompa, a PhD student at CERN, within the activities of MediaLab.  The application is controlled through body movements and the player is asked to set the right energy and the right angle of the hadron beam to make the (brain) cancer disappear. As part of her doctoral thesis, Jenny also built a questionnaire to hand out to visitors in order to examine their user experience. The goal of the study is to evaluate the effectiveness of using inter...

  7. Microcosm experiments to control anaerobic redox conditions when studying the fate of organic micropollutants in aquifer material.

    Science.gov (United States)

    Barbieri, Manuela; Carrera, Jesús; Sanchez-Vila, Xavier; Ayora, Carlos; Cama, Jordi; Köck-Schulmeyer, Marianne; López de Alda, Miren; Barceló, Damià; Tobella Brunet, Joana; Hernández García, Marta

    2011-11-01

    The natural processes occurring in subsurface environments have proven to effectively remove a number of organic pollutants from water. The predominant redox conditions revealed to be one of the controlling factors. However, in the case of organic micropollutants the knowledge on this potential redox-dependent behavior is still limited. Motivated by managed aquifer recharge practices microcosm experiments involving aquifer material, settings potentially feasible in field applications, and organic micropollutants at environmental concentrations were carried out. Different anaerobic redox conditions were promoted and sustained in each set of microcosms by adding adequate quantities of electron donors and acceptors. Whereas denitrification and sulfate-reducing conditions are easily achieved and maintained, Fe- and Mn-reduction are strongly constrained by the slower dissolution of the solid phases commonly present in aquifers. The thorough description and numerical modeling of the evolution of the experiments, including major and trace solutes and dissolution/precipitation of solid phases, have been proven necessary to the understanding of the processes and closing the mass balance. As an example of micropollutant results, the ubiquitous beta-blocker atenolol is completely removed in the experiments, the removal occurring faster under more advanced redox conditions. This suggests that aquifers constitute a potentially efficient alternative water treatment for atenolol, especially if adequate redox conditions are promoted during recharge and long enough residence times are ensured. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. A plasma ball in the Microcosm museum

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    Plasma balls, like the one shown here, are displayed in the Microcosm exhibition where families can visit to learn more about the experiments carried out in a research institute like CERN. Hands-on activities allow visitors to get a step closer to the research activities carried out at CERN.

  9. Survival study of enterotoxigenic Escherichia colistrain in seawater and wastewater microcosms.

    Science.gov (United States)

    Boukef Ben Omrane, I; El Bour, M; Mejri, S; Mraouna, R; Got, P; Troussellier, M; Boudabous, A

    2011-01-01

    In order to survey osmotic and oligotrophic stress consequence on pathogenic enterobacteria discharged in marine areas, we examined enterotoxigenic Escherichia coli (ETEC) and a reference (Ecoli O126:B16) strains during their survival (47 days) in wastewater microcosms, submerged in natural seawater and maintained in laboratory conditions. The results revealed that the survival time for the two strains was prolonged when bacterial cells were previously incubated in wastewater, with less cellular membrane damage. In addition, the wild clinical E. coli strain showed a better survival capacity than the reference E. coli strain one. For both, we noted some modifications in biochemical profiles relatively to the initial state, notably when they were previously incubated in wastewater microcosm.

  10. Effects of hydrocarbon contamination on a free living marine nematode community: Results from microcosm experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudi, E.; Essid, N.; Beyrem, H.; Hedfi, A.; Boufahja, F.; Aissa, P. [Laboratoire de Biosurveillance de l' Environnement, Zarzouna (Tunisia). Faculte des Sciences de Bizerte; Vitiello, P. [Centre d' Oceanologie de Marseille (France)

    2005-11-15

    Anthropogenic inputs of crude and refined petroleum hydrocarbons into the sea require knowledge of the effects of these contaminants on the receiving assemblages of organisms. A microcosm experiment was carried out to study the influence of diesel on a free living nematode community of a Tunisian lagoon. Sediments were contaminated by diesel that ranged in concentration from 0.5 to 20 mg diesel kg{sup -1} dry weight (dw), and effects were examined after 90 days. Gradual changes in community structure were revealed depending on the quantity of diesel administrated. In the medium (1 mg diesel kg{sup -1} and 5 mg diesel kg{sup -1} (dw)) and high (10 mg diesel kg{sup -1}, 15 mg diesel kg{sup -1} and 20 mg kg{sup -1} (dw)) treated microcosms, most univariate measures, including diversity and species richness, decreased significantly with increasing level of diesel contamination whereas nematode assemblage from the low treated microcosm (0.5 mg diesel kg{sup -1} (dw)) remained unaffected. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the diesel treatments were varied: Chaetonema sp. was eliminated at all doses tested and seemed to be intolerant species to diesel contamination; Pomponema sp. and Oncholaimus campylocercoides were significantly affected at all diesel contamination levels but they were not eliminated, these species were categorized as 'diesel-sensitive'; Hypodontolaimus colesi, Daptonema trabeculosum and Daptonema fallax which significantly increased respectively at 0.5, 1 and 5 mg diesel kg{sup -1} (dw) concentrations and appeared to be 'opportunistic' species at these doses whereas Marylynnia stekhoveni which increased at all high doses (10, 15 and 20 mg diesel kg{sup -1} (dw)) seemed to be a 'diesel-resistant' species. (author)

  11. A microcosm for the breeding of plants under controlled conditions

    International Nuclear Information System (INIS)

    D'Aquino, Luigi; Maglione, Maria Grazia; Minarini, Carla; Pandolfi Giuseppe; Lanza, Bruno; Atrigna, Mauro; De Filippo, Giovanni; Giannotta, Giovanni; Pedicini Antonio; Aprano Salvatore

    2015-01-01

    In order to enhance studies of the effects of multiple stress on plant physiology laboratory scale, in collaboration with FOS Srl and Sesmat Srl and the project application for organic PON02 0 0556 3 420580 «SMARTAGS-SMARt TAGS 'was conceived, designed and built a 'microcosm for the breeding of plants under biotic and abiotic stress conditioning '. [it

  12. Population dynamics of light-limited phytoplankton : Microcosm experiments

    NARCIS (Netherlands)

    Huisman, Jef

    This paper investigates the extent to which the predictions of an elementary model for light-limited growth are matched by laboratory experiments with light-limited phytoplankton. The model and experiments link the population dynamics of phytoplankton species with changes in the light gradient

  13. A New Exhibition in Microcosm

    CERN Document Server

    2000-01-01

    Sebastien Pelletier explains states of matter to an enthusiastic group of youngsters during the opening of a new exhibition in Microcosm last week. The Fun with Physics workshop will be offered to all 13-14 year olds in school groups visiting CERN this year. The new Microcosm contents have been developed in collaboration with the local teaching community, and cover particles and the forces that act between them.

  14. Comparison of an assay for Dehalococcoides DNA and a microcosm study in predicting reductive dechlorination of chlorinated ethenes in the field

    International Nuclear Information System (INIS)

    Lu Xiaoxia; Wilson, John T.; Kampbell, Donald H.

    2009-01-01

    The study aims to compare the detection of 16S rRNA gene of Dehalococcoides species and the microcosm study for biotransformation in predicting reductive dechlorination of chlorinated ethenes in ground water at hazardous waste sites. A total of 72 ground water samples were collected from 12 PCE or TCE contaminated sites in the United States. The samples were analyzed and used to construct microcosms in the laboratory. The results showed that the presence of Dehalococcoides DNA was well associated with dechlorination to ethene in the field. Nearly half of the wells where Dehalococcoides DNA was detected had ethene as a dechlorination end product. In comparison, for ground water samples of 16 wells where ethene was detected, ethene was produced in 11 of the corresponding microcosms. For most microcosms, during two years of incubation, dechlorination was less extensive than that observed in the field. - Positive results of the assay for Dehalococcoides DNA and the microcosm study may suggest that reductive dechlorination is occurring in the field

  15. Aromatic hydrocarbon degradation in hydrogen peroxide- and nitrate-amended microcosms

    International Nuclear Information System (INIS)

    Christian, B.J.; Pugh, L.B.; Clarke, B.H.

    1995-01-01

    Fifty microcosms were constructed using aquifer materials from a former coal gasification site and divided into four groups: poisoned control, nutrient-free control, hydrogen peroxide-amended, and nitrate-amended microcosms. Each microcosm contained site soil and groundwater in a 1.2-L glass media bottle. When depleted, hydrogen peroxide and sodium nitrate were injected into the microcosms. Microcosms were periodically sacrificed for analysis of polycyclic aromatic hydrocarbons (PAHs); monocyclic aromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylenes [BTEX]); total petroleum hydrocarbons (TPH); and heterotrophic plate counts (HPCs). BTEX and two- and three-ringed PAHs were degraded in microcosms receiving electron-acceptor additions compared to poisoned controls. Four-, five-, and six-ringed PAHs were not significantly degraded during this study. Except in poisoned controls, significant amounts of dissolved oxygen (DO) or nitrate were utilized, and microbial populations increased by 3 to 5 orders of magnitude compared to site soils used to assemble the microcosms (i.e., baseline samples)

  16. Systems identification: a theoretical method applied to tracer kinetics in aquatic microcosms

    International Nuclear Information System (INIS)

    Halfon, E.; Georgia Univ., Athens

    1974-01-01

    A mathematical model of radionuclide kinetics in a laboratory microcosm was built and the transfer parameters estimated by multiple regression and system identification techniques. Insight into the functioning of the system was obtained from analysis of the model. Methods employed have allowed movements of radioisotopes not directly observable in the experimental systems to be distinguished. Results are generalized to whole ecosystems

  17. Environmental assessment of surfactant using aquatic microcosm system; Konuma no suiken seitaikei ni oyobosu kaimen kasseizai no microcosm system wo mochiita hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Takamatsu, Y.; Matsumura, M. [University of Tsukuba, Tsukuba (Japan); Inamori, Y. [National Institute for Environmental Studies, Tsukuba (Japan); Sudo, R. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1995-10-10

    Microcosm system was applied to assess effect of surfactants on aquatic ecosystem. Surfactants such as LAS and Soap were added to an aquatic flask-size microcosm consisting of four species of bacteria as decomposer, one species of ciliate protozoa (Cyclidium glaucoma), two rotifers (Philodina sp. and Lepadella sp.) and one aquatic oligochaete (Aeolosoma hemprichi) as predator, and a green alga (Chlorella sp.) and a filamentous blue-green alga (Tolypothrix sp.) as producer. In the system, NOEC (no observed effect concentration) of LAS was below 1.5mg{center_dot}l{sup -1}, whereas soap was below 30mg{center_dot}l{sup -1}. Microcosm test is a pertinent tool to assess the effect of surfactant on ecosystem because microcosm test makes it possible to evaluate the effect of surfactant from a viewpoint of the interaction of microorganisms, material cycle and energy flow. With these respects, microcosm test is useful environmental assessment method which can reflect aquatic ecosystem. 10 refs., 6 figs., 1 tab.

  18. Biodegradation of weathered polystyrene films in seawater microcosms

    OpenAIRE

    Syranidou, Evdokia; Karkanorachaki, Katerina; Amorotti, Filippo; Franchini, Martina; Repouskou, Eftychia; Kaliva, Maria; Vamvakaki, Maria; Kolvenbach, Boris; Fava, Fabio; Corvini, Philippe F.-X.; Kalogerakis, Nicolas

    2017-01-01

    A microcosm experiment was conducted at two phases in order to investigate the ability of indigenous consortia alone or bioaugmented to degrade weathered polystyrene (PS) films under simulated marine conditions. Viable populations were developed on PS surfaces in a time dependent way towards convergent biofilm communities, enriched with hydrocarbon and xenobiotics degradation genes. Members of Alphaproteobacteria and Gammaproteobacteria were highly enriched in the acclimated plastic associate...

  19. Petroleum Oxidation in Marine Microcosms by Natural Microbial Assemblages

    Science.gov (United States)

    Wardlaw, G. D.; Reddy, C. M.; Nelson, R. K.; Ehrhardt, C. J.; Valentine, D. L.

    2006-12-01

    Millions of gallons of petroleum are emitted into marine environments each year and the oxidation of this oil by microbes is an important mechanism for mediating toxicity. In terms of quantity, petroleum is the most abundant organic pollutant impacting marine environments today. Recent advances in chromatography have led to the development of comprehensive two-dimensional gas chromatography (GC &GC). The acronym, GC GC, is used because orthogonal gas chromatographic separations are achieved in both analytical dimensions by using stationary phases with varying partitioning abilities and selectivity. This novel method has greatly expanded the analytical window of petroleum hydrocarbons and was used to track the loss of petroleum hydrocarbons in aerobic marine microcosm experiments. Sediment microcosms were composed of seawater and sediment collected from the Coal Oil Point (COP) seep field off the coast of Santa Barbara, CA. Oil collected directly from the reservoir underlying the seep field was added to each microcosm, and samples were incubated for one year. Net metabolism was tracked by quantifying oxygen consumption and carbon dioxide production. The loss of petroleum components was tracked with GC GC, whereas the bacterial and archaeal community structures were tracked using T-RFLP. Results of these incubation studies will be presented.

  20. Biodegradation of polycyclic aromatic hydrocarbons (PAH) from crude oil in sandy-beach microcosms

    International Nuclear Information System (INIS)

    Lepo, J.E.; Cripe, C.R.

    2000-01-01

    Experiments were conducted using triplicate microcosm chambers for each treatment of a simulated oil spill on a beach. The treatments were sterile control, 10 ppm of a rhamnolipid biosurfactant added to the seawater and bi-weekly inoculation of the microcosms with two marine bacteria that produce biosurfactants but degrade only n-alkanes. The results showed that raw seawater cycled through the microcosms over a 30-day period led to a substantial depletion of fluorene, phenanthrene, and other polyaromatic hydrocarbons (PAH). It was not possible to detect PAH in pooled test system effluents. The oiled-beach microcosms were run with sterile synthetic seawater to differentiate between wash out and degradation. Depletion of n-alkanes was noticed in the systems inoculated with the alkane-degrading microbes and virtually all the aromatic analytes were recoverable from the oiled sand. The other two treatments permitted the recovery of all the analytes (PAH or alkanes). Under aerobic conditions, the biodegradation by microorganisms indigenous to natural seawater supported that lower molecular weight PAH were substantially depleted, but not the n-alkanes under similar conditions. 16 refs., 4 tabs., 1 fig

  1. Microcosm 2015: showcasing real objects, real people and real discoveries

    CERN Multimedia

    CERN Bulletin

    2014-01-01

    Every year since its inauguration in 1994, the well-loved Microcosm exhibition has played host to tens of thousands of students, tourists and VIPs alike. But the ever-changing CERN landscape warranted a new look for the exhibition, which was last updated in 2003. On 8 December, Microcosm will close for refurbishment, making way for a new, interactive exhibition space to be opened summer 2015.   In the Accelerator zone, Microcosm visitors will don the helmet of an LHC operator. Social media tools will be integrated into the exhibit, allowing visitors to share their "beam" with friends at home. (Conceptual art for the new Microcosm exhibition.) While the Globe of Science and Innovation provides a spectacular introduction to CERN's key messages, Microcosm has always employed a more didactic approach. The new Microcosm will continue this complementary approach, whilst also immersing visitors into the day-to-day life of CERN people. "We want to highlight the ama...

  2. Use Of Statistical Tools To Evaluate The Reductive Dechlorination Of High Levels Of TCE In Microcosm Studies

    Science.gov (United States)

    A large, multi-laboratory microcosm study was performed to select amendments for supporting reductive dechlorination of high levels of trichloroethylene (TCE) found at an industrial site in the United Kingdom (UK) containing dense non-aqueous phase liquid (DNAPL) TCE. The study ...

  3. Quantitative survival of Leptospira interrogans in soil and water microcosms.

    Science.gov (United States)

    Casanovas-Massana, Arnau; Pedra, Gabriel Ghizzi; Wunder, Elsio A; Diggle, Peter J; Begon, Mike; Ko, Albert I

    2018-04-27

    Leptospira interrogans is the etiological agent of leptospirosis, a globally distributed zoonotic disease. Human infection usually occurs through skin exposure with water and soil contaminated with the urine of chronically infected animals. In this study, we aimed to quantitatively characterize the survival of Leptospira interrogans serovar Copenhageni in environmental matrices. We constructed laboratory microcosms to simulate natural conditions and determined the persistence of DNA markers in soil, mud, spring water and sewage using a qPCR and a PMA-qPCR assay. We found that L. interrogans does not survive at high concentrations in the tested matrices. No net growth was detected in any of the experimental conditions and in all cases the concentration of the DNA markers targeted decreased from the beginning of the experiment following an exponential decay with a decreasing decay rate over time. After 12 and 21 days of incubation the spiked concentration of 10 6 L. interrogans cells/mL or g decreased to approximately 100 cells/mL or g in soil and spring water microcosms, respectively. Furthermore, culturable L. interrogans persisted at concentrations under the limit of detection by PMA-qPCR or qPCR for at least 16 days in soil and 28 days in spring water. Altogether our findings suggest that the environment is not a multiplication reservoir, but a temporary carrier of the L. interrogans Copenhageni, although the observed prolonged persistence at low concentrations may still enable the transmission of the disease. IMPORTANCE Leptospirosis is a zoonotic disease caused by spirochetes of the genus Leptospira that primarily affects impoverished populations worldwide. Although leptospirosis is transmitted by contact with water and soil, little is known about the ability of the pathogen to survive in the environment. In this study, we quantitatively characterized the survival of L. interrogans in environmental microcosms and found that although it cannot multiply in water

  4. Corexit 9500 microcosm data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Relative abundance of bacterial groups in the microcosms. This dataset is associated with the following publication: Techtman, S., M. Zhuang, P. Campo-Moreno, E....

  5. MICROCOSM - INSTALLATION OF THE LHC MODEL

    CERN Multimedia

    2002-01-01

    This week, installation of a 6m long section of the LHC starts in Microcosm. This full-scale model is the first part of a new exhibition highlighting the technological challenges and the exciting physics of the LHC era. Many people at CERN have helped with the preparations for the model and the Microcosm team would like to thank all those involved. An inauguration for the press will take place at the start of the next school term.

  6. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

    KAUST Repository

    Tsiola, A.

    2015-12-01

    The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores.

  7. Ozone effects on Sphagnum mosses, carbon dioxide exchange and methane emission in boreal peatland microcosms

    International Nuclear Information System (INIS)

    Niemi, Riikka; Holopainen, Toini; Martikainen, Pertti J.; Silvola, Jouko

    2002-01-01

    Microcosms of a boreal peatland originating from an oligotrophic fen in Eastern Finland were fumigated under four ozone concentrations (0, 50, 100 and 150 ppb O 3 ) in laboratory growth chambers during two separate experiments (autumn and summer) for 4 and 6 weeks, respectively. Ozone effects on Sphagnum mosses and the fluxes of carbon dioxide and methane were evaluated. In both experiments, the three Sphagnum species studied showed only a few significant responses to ozone. In the autumn experiment, membrane permeability of S. angustifolium, measured as conductivity and magnesium leakage, was significantly higher under ozone fumigation (P=0.005 and 2 exchange during the 6-week-long summer experiment, but dark ecosystem respiration was transiently increased by ozone concentration of 100 ppb after 14 days of exposure (P<0.05). Fumigation with 100 ppb of ozone, however, more than doubled (P<0.05) methane emission from the peatland monoliths. Our results suggest that increasing tropospheric ozone concentration may cause substantial changes in the carbon gas cycling of boreal peatlands, even though these changes are not closely associated with the changes in Sphagnum vegetation

  8. Sunlight inactivation of Escherichia coli in waste stabilization microcosms in a sahelian region (Ouagadougou, Burkina Faso).

    Science.gov (United States)

    Maïga, Ynoussa; Denyigba, Kokou; Wethe, Joseph; Ouattara, Aboubakar Sidiki

    2009-02-09

    Experiments on sunlight inactivation of Escherichia coli were conducted from November 2006 to June 2007 in eight outdoors microcosms with different depths filled with maturation pond wastewater in order to determine pond depth influence on sunlight inactivation of E. coli. The long-term aim was to maximize sunlight inactivation of waterborne pathogens in waste stabilization ponds (WSPs) in sahelian regions where number of sunny days enable longer exposure of wastewater to sunlight. The inactivation was followed during daylight from 8.00 h to 17.00 h and during the night. Sunlight inactivation rates (K(S)), as a function of cumulative global solar radiation (insolation), were 16 and 24 times higher than the corresponding dark inactivation (K(D)) rates, respectively in cold and warm season. In warm season, E. coli was inactivated far more rapidly. Inactivation of E. coli follows the evolution of radiation during the day. In shallow depth microcosms, E. coli was inactivated far more rapidly than in high depth microcosms. The physical chemical parameters [pH, dissolved oxygen (DO)] of microcosms water were higher in shallow depth microcosms than in high depth microcosms suggesting a synergistic effect of sunlight and these parameters to damage E. coli. To increase the efficiency of the elimination of waterborne bacteria, the use of maturation ponds with intermediate depths (0.4m) would be advisable in view of the high temperatures and thus evaporation recorded in sahelian regions.

  9. In situ and laboratory determined first-order degradation rate constants of specific organic compounds in an aerobic aquifer

    DEFF Research Database (Denmark)

    Nielsen, P.H.; Bjerg, P.L.; Nielsen, P.

    1996-01-01

    In situ microcosms (ISM) and laboratory batch microcosms (LBM) were used for determination of the first-order degradation rate constants of benzene, toluene, o-xylene, nitrobenzene, naphthalene, biphenyl, o- and p-dichlorobenzene, 1,1,1 -trichloroethane, tetrachlorometane, trichloroethene......, tetrachloroethene, phenol, o-cresol, 2,4- and 2,6-dichlorophenol, 4,6-o-dichlorocresol, and o- and p-nitrophenol in an aerobic aquifer, All aromatic hydrocarbons were degraded in ISM and LBM experiments. The phenolic hydrocarbons were ail degraded in ISM experiments, but some failed to degrade in LBM experiments....... Chlorinated aliphatic hydrocarbons were degraded neither in ISM nor LBM experiments. Degradation rate constants were determined by a model accounting for kinetic sorption (bicontinuum model), lag phases, and first-order degradation. With a few exceptions, lag phases were less than 2 weeks in both ISM and LBM...

  10. Influence of erythromycin A on the microbial populations in aquaculture sediment microcosms

    International Nuclear Information System (INIS)

    Kim, Yong-Hak; Cerniglia, Carl E.

    2005-01-01

    Degradation of erythromycin A was studied using two sediment samples obtained from the salmon and trout hatchery sites at Hupp Springs (HS) and Goldendale (GD), Washington, United States. The former site had been treated for 3 years with erythromycin-medicated feed prior to the experiments, and the latter site had not been treated with any antibiotic for at least 6 years. The two sediment microcosms treated with either N-[methyl- 14 C]erythromycin A or [1,3,5,7,9,11,13- 14 C]erythromycin A showed S-curves for erythromycin A mineralization with a prolonged lag time of 120 days, except for GD microcosms treated with [1,3,5,7,9,11,13- 14 C]erythromycin A. We proposed a simplified logistic model to interpret the mineralization curves under the assumption of the low densities of initial populations metabolizing erythromycin A. The model was helpful for knowing the biological potential for erythromycin A degradation in sediments. Although erythromycin A added to the two sediment microcosms did not significantly alter the numbers of total viable aerobic bacteria or erythromycin-resistant bacteria, it affected the bacterial composition. The influence on the bacterial composition appeared to be greater in GD microcosms without pre-exposure to antibiotics. PCR-RFLP and DNA sequence analyses of the 16S ribosomal RNA gene and the erythromycin esterase (ere) gene revealed that ereA type 2 (ereA2) was present in potentially erythromycin-degrading Pseudomonas spp. strains GD100, GD200, HS100, HS200 and HS300, isolated from erythromycin-treated and non-treated GD and HS microcosms. Erythromycin A appeared to influence the development and proliferation of strain GD200, possibly via the lateral gene transfer of ereA2

  11. Influence of erythromycin A on the microbial populations in aquaculture sediment microcosms

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong-Hak [Division of Microbiology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079 (United States)]. E-mail: yhkim660628@hotmail.com; Cerniglia, Carl E. [Division of Microbiology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079 (United States)]. E-mail: ccerniglia@nctr.fda.gov

    2005-07-01

    Degradation of erythromycin A was studied using two sediment samples obtained from the salmon and trout hatchery sites at Hupp Springs (HS) and Goldendale (GD), Washington, United States. The former site had been treated for 3 years with erythromycin-medicated feed prior to the experiments, and the latter site had not been treated with any antibiotic for at least 6 years. The two sediment microcosms treated with either N-[methyl-{sup 14}C]erythromycin A or [1,3,5,7,9,11,13-{sup 14}C]erythromycin A showed S-curves for erythromycin A mineralization with a prolonged lag time of 120 days, except for GD microcosms treated with [1,3,5,7,9,11,13-{sup 14}C]erythromycin A. We proposed a simplified logistic model to interpret the mineralization curves under the assumption of the low densities of initial populations metabolizing erythromycin A. The model was helpful for knowing the biological potential for erythromycin A degradation in sediments. Although erythromycin A added to the two sediment microcosms did not significantly alter the numbers of total viable aerobic bacteria or erythromycin-resistant bacteria, it affected the bacterial composition. The influence on the bacterial composition appeared to be greater in GD microcosms without pre-exposure to antibiotics. PCR-RFLP and DNA sequence analyses of the 16S ribosomal RNA gene and the erythromycin esterase (ere) gene revealed that ereA type 2 (ereA2) was present in potentially erythromycin-degrading Pseudomonas spp. strains GD100, GD200, HS100, HS200 and HS300, isolated from erythromycin-treated and non-treated GD and HS microcosms. Erythromycin A appeared to influence the development and proliferation of strain GD200, possibly via the lateral gene transfer of ereA2.

  12. Closure of Microcosm for refurbishment

    CERN Multimedia

    2014-01-01

    Since 1994, the Microcosm exhibition has given the opportunity to visitors of all ages and backgrounds to have a first glimpse into the secrets of physics.   To ensure that Microcosm can continue fulfilling its educational aims at the same level of quality for many years to come, it is closing for renovation work on 8 December 2014 and is expected to reopen during Summer 2015. During the closure, the “Fun with Physics” workshop will not take place, but the Universe of Particles exhibition in the Globe and the Passport to the Big Bang circuit will remain accessible to the public, free of charge and with no need to book in advance.  Guided tours of CERN are also available (advance booking required via this page).

  13. Microbial community analysis of switchgrass planted and unplanted soil microcosms displaying PCB dechlorination.

    Science.gov (United States)

    Liang, Yi; Meggo, Richard; Hu, Dingfei; Schnoor, Jerald L; Mattes, Timothy E

    2015-08-01

    Polychlorinated biphenyls (PCBs) pose potential risks to human and environmental health because they are carcinogenic, persistent, and bioaccumulative. In this study, we investigated bacterial communities in soil microcosms spiked with PCB 52, 77, and 153. Switchgrass (Panicum virgatum) was employed to improve overall PCB removal, and redox cycling (i.e., sequential periods of flooding followed by periods of no flooding) was performed in an effort to promote PCB dechlorination. Lesser chlorinated PCB transformation products were detected in all microcosms, indicating the occurrence of PCB dechlorination. Terminal restriction fragment length polymorphism (T-RFLP) and clone library analysis showed that PCB spiking, switchgrass planting, and redox cycling affected the microbial community structure. Putative organohalide-respiring Chloroflexi populations, which were not found in unflooded microcosms, were enriched after 2 weeks of flooding in the redox-cycled microcosms. Sequences classified as Geobacter sp. were detected in all microcosms and were most abundant in the switchgrass-planted microcosm spiked with PCB congeners. The presence of possible organohalide-respiring bacteria in these soil microcosms suggests that they play a role in PCB dechlorination therein.

  14. Influence of sediment on the fate and toxicity of a polyethoxylated tallowamine surfactant system (MON 0818) in aquatic microcosms

    Science.gov (United States)

    Wang, N.; Besser, J.M.; Buckler, D.R.; Honegger, J.L.; Ingersoll, C.G.; Johnson, B. Thomas; Kurtzweil, M.L.; MacGregor, J.; McKee, M.J.

    2005-01-01

    The fate and toxicity of a polyethoxylated tallowamine (POEA) surfactant system, MON 0818, was evaluated in water–sediment microcosms during a 4-d laboratory study. A surfactant solution of 8 mg l−1 nominal concentration was added to each of nine 72-l aquaria with or without a 3-cm layer of one of two natural sediments (total organic carbon (TOC) 1.5% or 3.0%). Control well water was added to each of nine additional 72-l aquaria with or without sediment. Water samples were collected from the microcosms after 2, 6, 24, 48, 72, and 96 h of aging to conduct 48-h toxicity tests with Daphnia magna and to determine surfactant concentrations. Elevated mortality of D. magna (43–83%) was observed in overlying water sampled from water-only microcosms throughout the 96-h aging period, whereas elevated mortality (23–97%) was only observed in overlying water sampled from water–sediment microcosms during the first 24 h of aging. Measured concentrations of MON 0818 in water-only microcosms remained relatively constant (4–6 mg l−1) during the 96-h period, whereas the concentrations in overlying water from microcosms containing either of the two types of sediment dissipated rapidly, with half-lives of 13 h in the 3.0% TOC sediment and 18 h in the 1.5% TOC sediment. Both toxicity and the concentration of MON 0818 in overlying water decreased more rapidly in microcosms containing sediment with the higher percent TOC and clay and with a higher microbial biomass. Mortality of D. magna was significantly correlated with surfactant concentrations in the overlying water. These results indicate that the toxicity of the POEA surfactant in water rapidly declines in the presence of sediment due to a reduction in the surfactant concentration in the overlying water above the sediment.

  15. Ecological effects assessment of anionic surfactant on aquatic ecosystem using microcosm system; Microcosm wo mochiita in ion kaimen kasseizai no suiken seitaikei ni oyobosu eikyo hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Takamatsu, Y. [University of Tsukuba, Tsukuba (Japan); Inamori, Y. [National Institute for Environmental Studies, Tsukuba (Japan); Sudo, R. [Tohoku University, Sendai (Japan). Faculty of Engineering; Kurihara, Y. [Ou Univ., Fukushima (Japan). Faculty of Engineering; Matsumura, M. [University of Tsukuba, Tsukuba (Japan). Institute of Applied Biochemical

    1997-11-10

    Microcosm system was applied to assess effect of anionic surfactant (LAS) on aquatic ecosystem. Anionic surfactant such as LAS was added to an flask microcosm consisting of four species of bacteria as decomposer, one species of ciliate protozoa (Cyclidium glaucoma), two rotifers (Philodina sp. and Lepadella sp.) and one aquatic oligochaete (Aeolosoma hemprichi) as predator, and a green alga (Chlorella sp.) and a filamentous blue-green alga (Tolypothrix sp.) as producer, comparing with that of an natural lake model ecosystem derived from natural lake water. In the flask microcosm system and the natural lake model ecosystem, biodegradation rates of LAS were almost same and NOECs (no observed effect concentration) of LAS were also below 1.5 mg{center_dot} l{sup -1}. It was found that flask microcosm test could provide precise ecological effect assessment of LAS on number of microorganisms because the system showed higher reproducibility and stability than natural take model ecosystem. It was suggested that flask microcosm test was useful ecological effect assessment method which can reflect natural aquatic ecosystem. 10 refs., 4 figs., 2 tabs.

  16. Degradation of 1,1,2,2-tetrachloroethane and accumulation of vinyl chloride in wetland sediment microcosms and in situ porewater: biogeochemical controls and associations with microbial communities

    Science.gov (United States)

    Lorah, Michelle M.; Voytek, Mary A.

    2004-05-01

    The biodegradation pathways of 1,1,2,2-tetrachloroethane (TeCA) and 1,1,2-trichloroethane (112TCA) and the associated microbial communities in anaerobic wetland sediments were evaluated using concurrent geochemical and genetic analyses over time in laboratory microcosm experiments. Experimental results were compared to in situ porewater data in the wetland to better understand the factors controlling daughter product distributions in a chlorinated solvent plume discharging to a freshwater tidal wetland at Aberdeen Proving Ground, Maryland. Microcosms constructed with wetland sediment from two sites showed little difference in the initial degradation steps of TeCA, which included simultaneous hydrogenolysis to 112TCA and dichloroelimination to 1,2-dichloroethene (12DCE). The microcosms from the two sites showed a substantial difference, however, in the relative dominance of subsequent dichloroelimination of 112TCA. A greater dominance of 112TCA dichloroelimination in microcosms constructed with sediment that was initially iron-reducing and subsequently simultaneously iron-reducing and methanogenic caused approximately twice as much vinyl chloride (VC) production as microcosms constructed with sediment that was methanogenic only throughout the incubation. The microcosms with higher VC production also showed substantially more rapid VC degradation. Field measurements of redox-sensitive constituents, TeCA, and its anaerobic degradation products along flowpaths in the wetland porewater also showed greater production and degradation of VC with concurrent methanogenesis and iron reduction. Molecular fingerprinting indicated that bacterial species [represented by a peak at a fragment size of 198 base pairs (bp) by MnlI digest] are associated with VC production from 112TCA dichloroelimination, whereas methanogens (190 and 307 bp) from the Methanococcales or Methanobacteriales family are associated with VC production from 12DCE hydrogenolysis. Acetate-utilizing methanogens

  17. 1. Introduction. 2. Laboratory experiments. 3. Field experiments. 4. Integrated field-laboratory experiments. 5. Panel recommendations

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Some recommendations for the design of laboratory and field studies in marine radioecology are formulated. The difficulties concerning the comparability of various experimental methods used to measure the fluxes of radionuclides through marine organisms and ecosystems, and also the use of laboratory results to make predictions for the natural environment are discussed. Three working groups were established during the panel meeting, to consider laboratory experiments, field studies, and the design and execution of integrated laboratory and field studies respectively. A number of supporting papers dealing with marine radioecological experiments were presented

  18. Iron released from ilmenite mineral sustains a phytoplankton community in microcosms

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, C.E.G.; Velip, D.; Mourya, B.S.; Shaikh, S.; Das, A.; LokaBharathi, P.A.

    Natural biotic communities from Kalbadevi Bay were monitored in microcosms (1-l glass flasks) to test the hypothesis that iron released from ilmenite through microbial action contributes to proliferation of phytoplankton. Microcosms containing...

  19. Effects of microcosm scaling and food resources on growth and survival of larval Culex pipiens

    Directory of Open Access Journals (Sweden)

    Paradise Christopher J

    2001-08-01

    Full Text Available Abstract Background We used a simple experimental design to test for the effects of microcosm scaling on the growth and survival of the mosquito, Culex pipiens. Microcosm and mesocosm studies are commonly used in ecology, and there is often an assumption that scaling doesn't affect experimental outcomes. The assumption is implicit in the design; choice of mesocosms may be arbitrary or based on convenience or cost. We tested the hypothesis that scale would influence larvae due to depth and surface area effects. Larvae were predicted to perform poorly in microcosms that were both deep and had small openings, due to buildup of waste products, less exchange with the environment, and increased competition. To determine if the choice of scale affected responses to other factors, we independently varied leaf litter quantity, whose effects on mosquitoes are well known. Results We found adverse effects of both a lower wall surface area and lower horizontal surface area, but microcosm scale interacted with resources such that C. pipiens is affected by habitat size only when food resources are scarce. At low resource levels mosquitoes were fewer, but larger, in microcosms with smaller horizontal surface area and greater depth than in microcosms with greater horizontal surface area and shallower depth. Microcosms with more vertical surface area/volume often produced larger mosquitoes; more food may have been available since mosquitoes browse on walls and other substrates for food. Conclusions The interaction between habitat size and food abundance is consequential to aquatic animals, and choice of scale in experiments may affect results. Varying surface area and depth causes the scale effect, with small horizontal surface area and large depth decreasing matter exchange with the surrounding environment. In addition, fewer resources leads to less leaf surface area, and the effects of varying surface area will be greater under conditions of limiting resources

  20. Exposure and effects of sediment-spiked fludioxonil on macroinvertebrates and zooplankton in outdoor aquatic microcosms

    NARCIS (Netherlands)

    Yin, Xiaohui; Brock, Theo C.M.; Barone, Lidia E.; Belgers, J.D.M.; Boerwinkel, Marie Claire; Buijse, Laura; Wijngaarden, van René P.A.; Hamer, Mick; Roessink, Ivo

    2018-01-01

    Information from effects of pesticides in sediments at an ecosystem level, to validate current and proposed risk assessment procedures, is scarce. A sediment-spiked outdoor freshwater microcosm experiment was conducted with fludioxonil (lipophilic, non-systemic fungicide) to study exposure

  1. Design of Mixed Batch Reactor and Column Studies at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Wu, Weimin; Criddle, Craig S.

    2015-01-01

    We (the Stanford research team) were invited as external collaborators to contribute expertise in environmental engineering and field research at the ORNL IFRC, Oak Ridge, TN, for projects carried out at the Argonne National Laboratory and funded by US DOE. Specifically, we assisted in the design of batch and column reactors using ORNL IFRC materials to ensure the experiments were relevant to field conditions. During the funded research period, we characterized ORNL IFRC groundwater and sediments in batch microcosm and column experiments conducted at ANL, and we communicated with ANL team members through email and conference calls and face-to-face meetings at the annual ERSP PI meeting and national meetings. Microcosm test results demonstrated that U(VI) in sediments was reduced to U(IV) when amended with ethanol. The reduced products were not uraninite but unknown U(IV) complexes associated with Fe. Fe(III) in solid phase was only partially reduced. Due to budget reductions at ANL, Stanford contributions ended in 2011.

  2. Design of Mixed Batch Reactor and Column Studies at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Weimin [Stanford Univ., CA (United States); Criddle, Craig S. [Stanford Univ., CA (United States)

    2015-11-16

    We (the Stanford research team) were invited as external collaborators to contribute expertise in environmental engineering and field research at the ORNL IFRC, Oak Ridge, TN, for projects carried out at the Argonne National Laboratory and funded by US DOE. Specifically, we assisted in the design of batch and column reactors using ORNL IFRC materials to ensure the experiments were relevant to field conditions. During the funded research period, we characterized ORNL IFRC groundwater and sediments in batch microcosm and column experiments conducted at ANL, and we communicated with ANL team members through email and conference calls and face-to-face meetings at the annual ERSP PI meeting and national meetings. Microcosm test results demonstrated that U(VI) in sediments was reduced to U(IV) when amended with ethanol. The reduced products were not uraninite but unknown U(IV) complexes associated with Fe. Fe(III) in solid phase was only partially reduced. Due to budget reductions at ANL, Stanford contributions ended in 2011.

  3. A novel baiting microcosm approach used to identify the bacterial community associated with Penicillium bilaii hyphae in soil

    DEFF Research Database (Denmark)

    Ghodsalavi, Behnoushsadat; Svenningsen, Nanna Bygvraa; Hao, Xiuli

    2017-01-01

    It is important to identify and recover bacteria associating with fungi under natural soil conditions to enable eco-physiological studies, and to facilitate the use of bacterial-fungal consortia in environmental biotechnology. We have developed a novel type of baiting microcosm, where fungal hyphae...... interact with bacteria under close-to-natural soil conditions; an advantage compared to model systems that determine fungal influences on bacterial communities in laboratory media. In the current approach, the hyphae are placed on a solid support, which enables the recovery of hyphae with associated...... bacteria in contrast to model systems that compare bulk soil and mycosphere soil. We used the baiting microcosm approach to determine, for the first time, the composition of the bacterial community associating in the soil with hyphae of the phosphate-solubilizer, Penicillium bilaii. By applying...

  4. Evaluation of terrestrial microcosms for assessing the fate and effects of genetically engineered microorganisms on ecological processes

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, J.K.; Bentjen, S.A.; Bolton, H. Jr.; Li, S.W.; Ligotke, M.W.; McFadden, K.M.; Van Voris, P.

    1989-04-01

    This project evaluates and modifies the existing US Environmental Protection Agency's Office of Pesticides and Toxic Substances (EPA/OPTS) terrestrial microcosm test system and test protocols such that they can be used to determine the environmental fate and ecological hazards of genetically engineered microorganisms (GEMs). The intact soil-core microcosm represents terrestrial ecosystems, and when coupled with appropriate test protocols, such microcosms may be appropriate to define and limit risks associated with the intentional release of GEMs. The terrestrial microcosm test system was used to investigate the survival and transport of two model GEMs (Azospirillum lipoferum and Pseudomonas sp. Tn5 mutants) to various trophic levels and niches and through intact soil cores. Subsequent effects on nutrient cycling and displacement of indigenous microorganisms were evaluated. The model organisms were a diazotrophic root-colonizing bacterium (A. lipoferum) and a wheat root growth-inhibiting rhizobacterium (Pseudomonas sp.). The transposable element Tn5 was used as a genetic marker for both microorganisms in two separate experiments. The organisms were subjected to transposon mutagenesis using a broad host-range-mobilizable suicide plasmid. The transposon Tn5 conferred levels of kanamycin resistance up to 500 ..mu..g/ml (Pseudomonas sp.), which allowed for selection of the bacteria from environmental samples. The presence of Tn5 DNA in the genome of the model GEMs also allowed the use of Tn5 gene probes to confirm and enumerate the microorganisms in different samples from the microcosms. Two types of root growth-inhibiting Pseudomonas sp. Tn5 mutants were obtained and used in microcosm studies: those that lacked the ability to inhibit either wheat root growth or the growth of other microorganisms in vitro (tox/sup /minus//) and those which retained these properties (tox/sup +/). 53 refs., 7 figs., 6 tabs.

  5. Disturbance promotes non-indigenous bacterial invasion in soil microcosms

    DEFF Research Database (Denmark)

    Liu, Manqiang; Strandmark, Lisa Bjørnlund; Rønn, Regin

    2012-01-01

    Invasion-biology is largely based on non-experimental observation of larger organisms. Here, we apply an experimental approach to the subject. By using microbial-based microcosm-experiments, invasion-biology can be placed on firmer experimental, and hence, less anecdotal ground. A better...... understanding of the mechanisms that govern invasion-success of bacteria in soil communities will provide knowledge on the factors that hinder successful establishment of bacteria artificially inoculated into soil, e.g. for remediation purposes. Further, it will yield valuable information on general principles...... of invasion biology in other domains of life....

  6. Fate of neptunium in an anaerobic, methanogenic microcosm

    International Nuclear Information System (INIS)

    Banaszak, J.E.; Webb, S.M.; Rittmann, B.E.; Gaillard, J.F.; Reed, D.T.

    1999-01-01

    Neptunium is found predominantly as Np(IV) in reducing environments, but as Np(V) in aerobic environments. Currently, it is not known how the interplay between biotic and abiotic processes affects Np redox speciation in the environment. To evaluate the effect of anaerobic microbial activity on the fate of Np in natural systems, Np(V) was added to a microcosm inoculated with anaerobic sediments from a metal-contaminated freshwater lake. The consortium included metal-reducing, sulfate-reducing, and methanogenic microorganisms, and acetate was supplied as the only exogenous substrate. Addition of more than 10 -5 M Np did not inhibit methane production. Total Np solubility in the active microcosm, as well as in sterilized control samples, decreased by nearly two orders of magnitude. A combination of analytical techniques, including VIS-NIR absorption spectroscopy and XANES, identified Np(IV) as the oxidation state associated with the sediments. The similar results from the active microcosm and the abiotic controls suggest that microbially produced Mn(II/III) and Fe(II) may serve as electron donors for Np reduction

  7. Microcosm: s'instruire en s'amusant

    CERN Multimedia

    2003-01-01

    Since the 5th May, on the first Monday of each month, CERN Microcosm invites you to its "Lundis Découverte" presentations. Each presentation has a theme connected to the science and technology used at CERN (0.5 page)

  8. Laboratory evidence of MTBE biodegradation in Borden aquifer material

    Science.gov (United States)

    Schirmer, Mario; Butler, Barbara J.; Church, Clinton D.; Barker, James F.; Nadarajah, Nalina

    2003-02-01

    Mainly due to intrinsic biodegradation, monitored natural attenuation can be an effective and inexpensive remediation strategy at petroleum release sites. However, gasoline additives such as methyl tert-butyl ether (MTBE) can jeopardize this strategy because these compounds often degrade, if at all, at a slower rate than the collectively benzene, toluene, ethylbenzene and the xylene (BTEX) compounds. Investigation of whether a compound degrades under certain conditions, and at what rate, is therefore important to the assessment of the intrinsic remediation potential of aquifers. A natural gradient experiment with dissolved MTBE-containing gasoline in the shallow, aerobic sand aquifer at Canadian Forces Base (CFB) Borden (Ontario, Canada) from 1988 to 1996 suggested that biodegradation was the main cause of attenuation for MTBE within the aquifer. This laboratory study demonstrates biologically catalyzed MTBE degradation in Borden aquifer-like environments, and so supports the idea that attenuation due to biodegradation may have occurred in the natural gradient experiment. In an experiment with batch microcosms of aquifer material, three of the microcosms ultimately degraded MTBE to below detection, although this required more than 189 days (or >300 days in one case). Failure to detect the daughter product tert-butyl alcohol (TBA) in the field and the batch experiments could be because TBA was more readily degradable than MTBE under Borden conditions.

  9. Interrelated experiments in laboratory and space plasmas

    International Nuclear Information System (INIS)

    Koepke, M. E.

    2005-01-01

    Many advances in understanding space plasma phenomena have been linked to insight derived from theoretical modelling and/or laboratory experiments. Here are discussed advances for which laboratory experiments played an important role. How the interpretation of the space plasma data was influenced by one or more laboratory experiments is described. The space-motivation of laboratory investigations and the scaling of laboratory plasma parameters to space plasma conditions are discussed. Examples demonstrating how laboratory experiments develop physical insight, benchmark theoretical models, discover unexpected behaviour, establish observational signatures, and pioneer diagnostic methods for the space community are presented. The various device configurations found in space-related laboratory investigations are outlined. A primary objective of this review is to articulate the overlapping scientific issues that are addressable in space and lab experiments. A secondary objective is to convey the wide range of laboratory and space plasma experiments involved in this interdisciplinary alliance. The interrelation ship between plasma experiments in the laboratory and in space has a long history, with numerous demonstrations of the benefits afforded the space community by laboratory results. An experiment's suitability and limitations for investigating space processes can be quantitatively established using dimensionless parameters. Even with a partial match of these parameters, aspects of waves, instabilities, nonlinearities, particle transport, reconnection, and hydrodynamics are addressable in a way useful to observers and modelers of space phenomena. Because diagnostic access to space plasmas, laboratory-experimentalists awareness of space phenomena, and efforts by theorists and funding agencies to help scientists bridge the gap between the space and laboratory communities are increasing, the range of laboratory and space plasma experiments with overlapping scientific

  10. Investigation into ammonia stress on Cyperus alternifolius and its impact on nutrient removal in microcosm experiments.

    Science.gov (United States)

    Tao, Wendong; Han, Jianqiu; Li, Hanyan

    2015-11-01

    Ammonia stress on plants has been investigated at discrete ammonia concentrations in constructed wetlands. This study introduced a Gaussian model to simulate the kinetics of ammonia stress and investigated reversible and irreversible ammonia stress on Cyperus alternifolius in wetland-like microcosms. Ammonia stress on plant weight increase and oxygen release potential started at weekly ammonia concentrations of 27 and 28 mg N/L, reached 50% inhibition at 178 and 158 mg N/L, and resulted in lethal effects at 311 and 303 mg N/L, respectively. The stress of one-time ammonia concentrations up to 400 mg N/L could be reversible. Ammonia concentrations constantly above 219 mg N/L exerted irreversible stress. In the microcosms with ammonia concentrations above the 50% inhibition levels, plants played a minor role in nitrogen removal. Nitrogen removal performance was not affected considerably by ammonia stress. Orthophosphate removal was suppressed by ammonia stress due to less plant uptake. Design and operation of constructed wetlands should consider wastewater ammonia concentration so that the integrity of constructed wetland ecosystems can be maintained. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Chlordecone fate and mineralisation in a tropical soil (andosol) microcosm under aerobic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Bayo, Jesus D., E-mail: fernanje@supagro.inra.fr [IRD, UMR LISAH Bât 24, 2 Place Viala, 34060 Montpellier cedex 1 (France); INRA, UMR LISAH Bât 24, 2 Place Viala, 34060 Montpellier cedex 1 (France); Saison, Carine [IRD, UMR LISAH Bât 24, 2 Place Viala, 34060 Montpellier cedex 1 (France); Voltz, Marc [INRA, UMR LISAH Bât 24, 2 Place Viala, 34060 Montpellier cedex 1 (France); Disko, Ulrich; Hofmann, Diana; Berns, Anne E. [Forschungszentrum Jülich GmbH, IBG 3, 52425 Jülich (Germany)

    2013-10-01

    Chlordecone is a persistent organochlorine insecticide that, even decades after its ban, poses a threat to the environment and human health. Nevertheless, its environmental fate in soils has scarcely been investigated, and elementary data on its degradation and behaviour in soil are lacking. The mineralisation and sorption of chlordecone and the formation of possible metabolites were evaluated in a tropical agricultural andosol. Soil microcosms with two different soil horizons (S-A and S-B) were incubated for 215 days with {sup 14}C-chlordecone. At five different times (1, 33, 88, 150 and 215 days) the extractability of {sup 14}C-chlordecone was analysed. Mineralisation was monitored using {sup 14}CO{sub 2} traps of NaOH. The appearance of metabolites was studied using thin layer and gas chromatography techniques. At the end of the experiment, the water soluble {sup 14}C-activity was 2% of the remaining {sup 14}C-chlordecone for S-A and 8% for S-B. Only 12% of the remaining activity was non extractable and more than 80% remained extractable with organic solvents. For the first time to our knowledge, a significant mineralisation of chlordecone was measured in a microcosm under aerobic conditions (4.9% for S-A and 3.2% for S-B of the initial {sup 14}C-activity). The drastically lower emission of {sup 14}CO{sub 2} in sterilised microcosms indicated the biological origin of chlordecone mineralisation in the non-sterilised microcosms. No metabolites could be detected in the soil extracts. The mineralisation rate of chlordecone decreased by one order of magnitude throughout the incubation period. Thus, the chlordecone content in the soil remained large. This study confirms the existence of chlordecone degrading organisms in a tropical andosol. The reasons why their activity is restricted should be elucidated to allow the development of bioremediation approaches. Possible reasons are a heterogeneous distribution a chlordecone between sub-compartments with different

  12. Chlordecone fate and mineralisation in a tropical soil (andosol) microcosm under aerobic conditions

    International Nuclear Information System (INIS)

    Fernández-Bayo, Jesus D.; Saison, Carine; Voltz, Marc; Disko, Ulrich; Hofmann, Diana; Berns, Anne E.

    2013-01-01

    Chlordecone is a persistent organochlorine insecticide that, even decades after its ban, poses a threat to the environment and human health. Nevertheless, its environmental fate in soils has scarcely been investigated, and elementary data on its degradation and behaviour in soil are lacking. The mineralisation and sorption of chlordecone and the formation of possible metabolites were evaluated in a tropical agricultural andosol. Soil microcosms with two different soil horizons (S-A and S-B) were incubated for 215 days with 14 C-chlordecone. At five different times (1, 33, 88, 150 and 215 days) the extractability of 14 C-chlordecone was analysed. Mineralisation was monitored using 14 CO 2 traps of NaOH. The appearance of metabolites was studied using thin layer and gas chromatography techniques. At the end of the experiment, the water soluble 14 C-activity was 2% of the remaining 14 C-chlordecone for S-A and 8% for S-B. Only 12% of the remaining activity was non extractable and more than 80% remained extractable with organic solvents. For the first time to our knowledge, a significant mineralisation of chlordecone was measured in a microcosm under aerobic conditions (4.9% for S-A and 3.2% for S-B of the initial 14 C-activity). The drastically lower emission of 14 CO 2 in sterilised microcosms indicated the biological origin of chlordecone mineralisation in the non-sterilised microcosms. No metabolites could be detected in the soil extracts. The mineralisation rate of chlordecone decreased by one order of magnitude throughout the incubation period. Thus, the chlordecone content in the soil remained large. This study confirms the existence of chlordecone degrading organisms in a tropical andosol. The reasons why their activity is restricted should be elucidated to allow the development of bioremediation approaches. Possible reasons are a heterogeneous distribution a chlordecone between sub-compartments with different microbial activities or a degradation of

  13. Microcosm studies on iron and arsenic mobilization from aquifer sediments under different conditions of microbial activity and carbon source

    Science.gov (United States)

    Duan, Mengyu; Xie, Zuoming; Wang, Yanxin; Xie, Xianjun

    2009-05-01

    Microcosm experiments were conducted to understand the mechanism of microbially mediated mobilization of Fe and As from high arsenic aquifer sediments. Arsenic-resistant strains isolated from aquifer sediments of a borehole specifically drilled for this study at Datong basin were used as inoculated strains, and glucose and sodium acetate as carbon sources for the experiments. In abiotic control experiments, the maximum concentrations of Fe and As were only 0.47 mg/L and 0.9 μg/L, respectively. By contrast, the maximum contents of Fe and As in anaerobic microcosm experiments were much higher (up to 1.82 mg/L and 12.91 μg/L, respectively), indicating the crucial roles of microbial activities in Fe and As mobilization. The observed difference in Fe and As release with different carbon sources may be related to the difference in growth pattern and composition of microbial communities that develop in response to the type of carbon sources.

  14. Naturally-Derived Microcosms for Estimating Stress Effects in Aquatic Ecosystems

    Science.gov (United States)

    1991-05-31

    Respiration; RAIII: Protozoans: Lub 06 Biomonitoring; Enzyme; Ecotoxicology : Microcoasm; Artificial L aa Substrates 19. ABSTRACT (Continue on tverie...and macrophytes for 5 weeks and found that CV’s for most microcosm measures were 10 to 30% and that CV’s decreased as microcosms matured. Brockway et...212 Contract DAMD17-88-C-8068 convey ecotoxicological meaning and provide investigators with resolving power for finding differences. At the present

  15. TiO2 nanoparticles for the remediation of eutrophic shallow freshwater systems: Efficiency and impacts on aquatic biota under a microcosm experiment.

    Science.gov (United States)

    Bessa da Silva, Márcia; Abrantes, Nelson; Nogueira, Verónica; Gonçalves, Fernando; Pereira, Ruth

    2016-09-01

    The application of nanomaterials (NMs) in the remediation of eutrophic waters, particularly in the control of internal loading of nutrients, has been started, but limited investigations evaluated the effectiveness of these new treatment approaches and of their potential impacts on species from shallow freshwater lakes. The present work investigated, under a microcosm experiment, the application of a TiO2 nanomaterial both for reducing nutrient (mainly phosphorus and nitrogen forms) desorption and release from sediments (preventive treatment-PT) and for eliminating algal blooms (remediation treatment-RT). Furthermore, we also intended to assess the potential impacts of nano-TiO2 application on key freshwater species. The results showed the effectiveness of nano-TiO2 in controlling the release of phosphates from surface sediment and the subsequent reduction of total phosphorus in the water column. A reduction in total nitrogen was also observed. Such changes in nutrient dynamics contributed to a progressive inhibition of development of algae after the application of the NM in PT microcosms. Concerning the ability of nano-TiO2 to interact with algal cells, this interaction has likely occurred, mainly in RT, enhancing the formation of aggregates and their rapid settlement, thus reducing the algal bloom. Both treatments caused deleterious effects on freshwater species. In PT, Daphnia magna and Lemna minor showed a significant inhibition of several endpoints. Conversely, no inhibitory effect on the growth of Chironomus riparius was recorded. In opposite, C. riparius was the most affected species in RT microcosms. Such difference was probably caused by the formation of larger TiO2-algae aggregates in RT, under a high algal density, that rapidly settled in the sediment, becoming less available for pelagic species. In summary, despite the effectiveness of both treatments in controlling internal nutrient loading and in the mitigating algal bloom episodes, their negative

  16. A microcosm system to evaluate the toxicity of the triazine herbicide simazine on aquatic macrophytes

    International Nuclear Information System (INIS)

    Vervliet-Scheebaum, Marco; Straus, Alain; Tremp, Horst; Hamer, Mick; Maund, Stephen J.; Wagner, Edgar; Schulz, Ralf

    2010-01-01

    This study evaluates the effects of the triazine herbicide simazine in an outdoor pond microcosm test system that contained two submerged rooted species (Myriophyllum spicatum and Elodea canadensis) and two emergent rooted species (Persicaria amphibia and Glyceria maxima) over a period of 84 days. Simazine was applied to the microcosms at nominal concentrations of 0.05, 0.5 and 5 mg/L. General biological endpoints and physiological endpoints were used to evaluate herbicide toxicity on macrophytes and the algae developing naturally in the system. Concentration-related responses of macrophytes and algae were obtained for the endpoints selected, resulting in a no observed ecologically adverse effect concentration (NOEAEC) at simazine concentrations of 0.05 mg active ingredient/L after 84 days. E. canadensis was the most negatively affected species based on length increase, which was consistently a very sensitive parameter for all macrophytes. The experimental design presented might constitute a suitable alternative to conventional laboratory single-species testing. - Simazine at concentrations of 0.05 mg/L does not cause long-term negative effects to aquatic macrophytes or algae.

  17. A microcosm system to evaluate the toxicity of the triazine herbicide simazine on aquatic macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Vervliet-Scheebaum, Marco, E-mail: marco.vervliet@biologie.uni-freiburg.d [Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg (Germany); Straus, Alain [Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg (Germany); Tremp, Horst [Institute for Environmental Sciences, University Koblenz-Landau, Fortstr. 7, 76829 Landau (Germany); Hamer, Mick [Ecological Sciences, Syngenta Crop Protection AG, Jealott' s Hill International Research Centre, Bracknell, Berkshire RG42 6EY (United Kingdom); Maund, Stephen J. [Ecological Sciences, Syngenta Crop Protection AG, 4002 Basel (Switzerland); Wagner, Edgar [Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg (Germany); Schulz, Ralf [Institute for Environmental Sciences, University Koblenz-Landau, Fortstr. 7, 76829 Landau (Germany)

    2010-02-15

    This study evaluates the effects of the triazine herbicide simazine in an outdoor pond microcosm test system that contained two submerged rooted species (Myriophyllum spicatum and Elodea canadensis) and two emergent rooted species (Persicaria amphibia and Glyceria maxima) over a period of 84 days. Simazine was applied to the microcosms at nominal concentrations of 0.05, 0.5 and 5 mg/L. General biological endpoints and physiological endpoints were used to evaluate herbicide toxicity on macrophytes and the algae developing naturally in the system. Concentration-related responses of macrophytes and algae were obtained for the endpoints selected, resulting in a no observed ecologically adverse effect concentration (NOEAEC) at simazine concentrations of 0.05 mg active ingredient/L after 84 days. E. canadensis was the most negatively affected species based on length increase, which was consistently a very sensitive parameter for all macrophytes. The experimental design presented might constitute a suitable alternative to conventional laboratory single-species testing. - Simazine at concentrations of 0.05 mg/L does not cause long-term negative effects to aquatic macrophytes or algae.

  18. Variability of Biological Degradation of Phenolic Hydrocarbons in an Aerobic Aquifer Determined by Laboratory Batch Experiments

    DEFF Research Database (Denmark)

    Nielsen, Per Henning; Christensen, Thomas Højlund

    1994-01-01

    The biological aerobic degradation of 7 phenolic hydrocarbons (phenol, o-cresol, o-nitrophenol, p-nitrophenol, 2,6-dichlorophenol, 2,4-dichlorophenol, 4,6-o-dichlorocresol) and 1 aromatic hydrocarbon (nitrobenzene) was studied for 149 days in replicate laboratory batch microcosms with sediment...... and groundwater from 8 localities representing a 15 m × 30 m section of an aerobic aquifer. Three patterns of variation were found: (1) phenol, o-cresol and in most cases p-nitrophenol showed very fast degradation with no or only short lag phases and with very little variation among localities; (2) 2...

  19. A DNA Origami Mechanical Device for the Regulation of Microcosmic Structural Rigidity.

    Science.gov (United States)

    Wan, Neng; Hong, Zhouping; Wang, Huading; Fu, Xin; Zhang, Ziyue; Li, Chao; Xia, Han; Fang, Yan; Li, Maoteng; Zhan, Yi; Yang, Xiangliang

    2017-11-01

    DNA origami makes it feasible to fabricate a tremendous number of DNA nanostructures with various geometries, dimensions, and functionalities. Moreover, an increasing amount of research on DNA nanostructures is focused on biological and biomedical applications. Here, the reversible regulation of microcosmic structural rigidity is accomplished using a DNA origami device in vitro. The designed DNA origami monomer is composed of an internal central axis and an external sliding tube. Due to the external tube sliding, the device transforms between flexible and rigid states. By transporting the device into the liposome, the conformational change of the origami device induces a structural change in the liposome. The results obtained demonstrate that the programmed DNA origami device can be applied to regulate the microcosmic structural rigidity of liposomes. Because microcosmic structural rigidity is important to cell proliferation and function, the results obtained potentially provide a foundation for the regulation of cell microcosmic structural rigidity using DNA nanostructures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Microcosm investigations of stormwater pond sediment toxicity to embryonic and larval amphibians: Variation in sensitivity among species

    Energy Technology Data Exchange (ETDEWEB)

    Snodgrass, Joel W. [Department of Biological Sciences, Towson University, 8000 York Road, Towson, MD 21252 (United States)], E-mail: jsnodgrass@towson.edu; Casey, Ryan E. [Department of Chemistry, Towson University, 8000 York Road, Towson, MD 21252 (United States); Joseph, Debra; Simon, Judith A. [Department of Biological Sciences, Towson University, 8000 York Road, Towson, MD 21252 (United States)

    2008-07-15

    Stormwater ponds have become common features of modern development and often represent significant amounts of open space in urbanized areas. Although stormwater ponds may provide habitat for wildlife, factors responsible for producing variation in wildlife use of ponds have received limited attention. To investigate the role of variation in species tolerances of pollutants in structuring pond-breeding amphibian assemblages, we exposed species tolerant (Bufo americanus) and not tolerant (Rana sylvatica) of urbanization to pond sediments in laboratory microcosms. Pond microcosms had elevated sediment metal levels and chloride water concentrations. Among R. sylvatica embryos, exposure to pond sediments resulted in 100% mortality. In contrast, B. americanus embryos and larvae experienced only sublethal effects (i.e., reduced size at metamorphosis) due to pond sediment exposure. Our results suggest variation in pollutant tolerance among early developmental stages of amphibians may act in concert with terrestrial habitat availability to structure amphibian assemblages associated with stormwater ponds. - Variation among species in sensitivity to pollutants can influence stormwater pond amphibian assemblages.

  1. Glyceria maxima as new test species for the EU risk assessment for herbicides: a microcosm study.

    Science.gov (United States)

    Mohr, S; Schott, J; Hoenemann, L; Feibicke, M

    2015-03-01

    In its recent guidance document on tiered risk assessment for plant protection products for aquatic organisms, the European Food Safety Authority (EFSA) proposed to use Glyceria maxima as monocotyledonous grass species for the testing of special herbicide groups. However, published toxicity data for this species is very limited and there is no test guideline for Glyceria sp. For this reason a microcosm study was conducted in order to gain experience on the degree of sensitivity of G. maxima to the herbicidal substances clodinafop-propargyl (grass herbicide) and fluroxypyr (auxin) in comparison to the already established test organism water milfoil Myriophyllum spicatum and the duckweed species Landoltia punctata. Five concentrations without replicates were tested for each test substance using 10 microcosms and three microcosms served as controls. The experiment was run for 8 weeks. Morphological endpoints were used to determine growth and EC50 values. The results show that M. spicatum was most sensitive to fluroxypyr (37 days EC50 for roots: 62 µg/L) and G. maxima most sensitive to clodinafop-propargyl (22 days EC50 for total shoot length: 48 µg/L) whereas the duckweed species was considerable less sensitive. Hence, G. maxima turns out to be a good candidate for testing grass specific herbicides, supporting its inclusion as an additional macrophyte test for the risk assessment of herbicides as proposed by the EFSA.

  2. Assessment of the acute toxicity of eutrophic sediments after the addition of calcium nitrate (Ibirité reservoir, Minas Gerais-SE Brazil: initial laboratory experiments

    Directory of Open Access Journals (Sweden)

    H. Janke

    Full Text Available This study evaluated the acute toxicity of sediment in a eutrophic reservoir after remediation with a calcium nitrate solution to retain phosphorus. The study involved microcosms of surface sediments and water from the sediment-water interface in the Ibirité reservoir. This reservoir, located in the vicinity of metropolitan Belo Horizonte (Minas Gerais, SE Brazil, is a water body that receives treated effluents from an oil refinery (REGAP-Petrobras, as well as high loads of untreated urban effluents from the city of Ibirité and surrounding areas and industrial effluents from a major industrial park. Incubation times of the treatment experiments were: t = 0, t = 5, t = 10, t = 25, t = 50, t = 85 and t = 135 days. One control microcosm and three treated microcosms were analysed in each time interval. Acute toxicity of water samples was assessed with Ceriodaphnia silvestrii Daday, 1902 and that of bulk sediment samples with Chironomus xanthus Rempel, 1939. Toxicity tests were carried out concomitantly with chemical analyses of dissolved inorganic nitrogen species (ammonia, nitrate and nitrite, sulfate and metals in the water samples of the microcosms. Acid volatile sulfides (AVS, simultaneously extracted metal (SEM and potentially bioavailable metal were analyzed in bulk sediment samples. Neither of the tested organisms showed toxicity in the control microcosm samples. The water column of the treated microcosm showed toxicity to C. silvestrii, starting at t = 10 days, while the sediment pore water toxicity started at t = 0 day. However, toxicity was found to decline from t = 85 days to t = 135 days. Sediments showed toxicity to C. xanthus during the entire experiment, except at the longest incubation time (t = 135 days. The overall results indicate that nitrate, which reached concentrations exceeding 1,200 mg N-NO3- L-1 in the sediment pore water of the treated microcosms, was most probably responsible for the toxicity of the samples. Although

  3. Virtual laboratory for radiation experiments

    International Nuclear Information System (INIS)

    Tiftikci, A.; Kocar, C.; Tombakoglu, M.

    2009-01-01

    Simulation of alpha, beta and gamma radiation detection and measurement experiments which are part of real nuclear physics laboratory courses was realized with Monte Carlo method and JAVA Programming Language. As being known, establishing this type of laboratories are very expensive. At the same time, highly radioactive sources used in some experiments carries risk for students and also for experimentalists. By taking into consideration of those problems, the aim of this study is to setup a virtual radiation laboratory with minimum cost and to speed up the training of radiation physics for students with no radiation risk. Software coded possesses the nature of radiation and radiation transport with the help of Monte Carlo method. In this software, experimental parameters can be changed manually by the user and experimental results can be followed synchronous in an MCA (Multi Channel Analyzer) or an SCA (Single Channel Analyzer). Results obtained in experiments can be analyzed by these MCA or SCA panels. Virtual radiation laboratory which is developed in this study with reliable results and unlimited experimentation capability seems as an useful educational material. Moreover, new type of experiments can be integrated to this software easily and as a result, virtual laboratory can be extended.

  4. Scattering of phytoplankton cells from cytometry during a microcosm experiment

    Science.gov (United States)

    Moutier, W.; Duforêt-Gaurier, L.; Loisel, H.; Thyssen, M.; Mériaux, X.; Desailly, D.; Courcot, L.; Dugenne, M.

    2016-02-01

    This study presents an application of the CytoSense flow cytometer (CytoBuoy b.v., NL) as a powerful tool to analyze optical properties of phytoplankton cells. Recently, Duforêt et al., (2015) developed a methodology to derive the forward, sideward and backward cross section (σFWS, σSWS and σbb, respectively) of individual particles from the CytoSense. For the first time, this methodology was applied to phytoplankton cultures. A 20 day microcosm experiment was conducted on two phytoplankton species (Chlamydomonas concordia and Thalassiosira pseudonana). We realized daily sampling for biogeochemical and flow cytometer analysis and carried out optical measurements. Scanning electron migrographs (SEM) were performed at different life stages to investigate the cells morphology.First, CytoSense estimates were tested against radiative transfer computations. The comparison exercise, is based on radiative transfer simulations because for phytoplankton cultures, in situ measurements of σFWS and σSWS, particle by particle, are not available in literature. For that purpose, we build a database of 590,000 simulations, considering homogeneous and multi-layered spheres, to represent the optical properties of a large diversity of phytoplankton cells. Comparison showed that the CytoSense estimates for the cultures are consistent with values predicted by the theory. Second, the flow cytometer was used to analyze the temporal course of the forward and the sideward efficiency during the entire life-cycle. Results showed differences between the two species. From an ACP analysis, the variation of the optical properties were associated with the chlorophyll-a concentration by living cell, the thickness of the frustule and the aggregate formation. To finish, the bulk backscattering coefficient was rebuilt from σbb of individual cells and compare with the bb measured by a WET Labs ECO-BB9. Relative errors (RE) were between 0.3 and 0.47 and the mean RE was of 0.36. A such work shows

  5. Studies on the restoration succession of PFU microbial communities in a pilot-scale microcosm.

    Science.gov (United States)

    Jiang, Jian-Guo; Shen, Yun-Fen

    2007-06-01

    In order to imitate the restoration succession process of natural water ecosystem, a laboratory microcosm system of constant-flow-restoration was designed and established. A eutrophycation lake, Lake Donghu, was selected as the subject investigated. Six sampling stations were set on the lake, among which the water of station IV was natural clean water, and others were polluted with different degrees. Polyurethane foam unit microbial communities, which had colonized in the stations for a month, were collected from these stations and placed in their respective microcosms, using clean water of station IV to gradually replace the water of these microcosms. In this process, the healthy community in clean water continuously replaced the damaged communities in polluted water, the restoration succession of the damaged communities was characterized by weekly determination of several functional and structural community parameters, including species number (S), diversity index (DI), community pollution value (CPV), heterotrophy index (HI), and similarity coefficient. Cluster analysis based on similarity coefficient was used to compare the succession discrepancies of these microbial communities from different stations. The ecological succession of microbial communities during restoration was investigated by the variable patterns of these parameters, and based on which, the restoration standards of these polluted stations were suggested in an ecological sense. That was, while being restored, the water of station 0 (supereutrophycation) should be substituted with natural clean water by 95%; station I (eutrophycation), more than 90%; station II (eutrophycation), more than 85%; station III (eutrophycation), about 85%; station V (mesoeutrophycation), less than 50%. The effects of the structural and functional parameters in monitoring and assessing ecological restoration are analyzed and compared.

  6. Holistic study of an aquatic microcosm: theoretical and practical implications

    Energy Technology Data Exchange (ETDEWEB)

    Heath, R.T.

    1979-01-01

    The behavior of any system cannot by understood fully unless it is investigated as an intact unit over a range of states. The main task of holistic investigation is to determine the patterns of the set of responses and state transitions of a system and to examine the state space for trends, phases, and thresholds. Small laboratory ecosystems are ideal tools for holistic investigation of ecosystem function, because they are replicable and state settable. A small aquatic microcosm was characterized holistically as an example of this approach. Comparison of the nominal behavior of this system with its behavior under various degrees of cadmium stress (1, 10, 100 ppM Cd) indicated that holistic investigation of such systems is a sensitive and rapid means of assessing stress at the community level of organization.

  7. Non-methane biogenic volatile organic compound emissions from boreal peatland microcosms under warming and water table drawdown

    DEFF Research Database (Denmark)

    Faubert, P; Tiiva, P; Nakam, TA

    2011-01-01

    assessed the combined effect of warming and water table drawdown on the BVOC emissions from boreal peatland microcosms. We also assessed the treatment effects on the BVOC emissions from the peat soil after the 7-week long experiment. Emissions of isoprene, monoterpenes, sesquiterpenes, other reactive VOCs...

  8. The influence of nickel on the bioremediation of multi-component contaminated tropical soil: microcosm and batch bioreactor studies.

    Science.gov (United States)

    Taketani, Natália Franco; Taketani, Rodrigo Gouvêa; Leite, Selma Gomes Ferreira; Rizzo, Andrea Camardella de Lima; Tsai, Siu Mui; da Cunha, Cláudia Duarte

    2015-07-01

    Large petrochemical discharges are responsible for organic and inorganic pollutants in the environment. The purpose of this study was to evaluate the influence of nickel, one of the most abundant inorganic element in crude oil and the main component of hydrogen catalysts for oil refining, on the microbial community structure in artificially petroleum-contaminated microcosms and in solid phase bioreactor studies. In the presence of metals, the oil biodegradation in microcosms was significantly delayed during the first 7 days of operation. Also, increasing amounts of moisture generated a positive influence on the biodegradation processes. The oil concentration, exhibiting the most negative influence at the end of the treatment period. Molecular fingerprinting analyses (denaturing gradient gel electrophoresis--DGGE) indicated that the inclusion of nickel into the contaminated soil promoted direct changes to the microbial community structure. By the end of the experiments, the results of the total petroleum hydrocarbons removal in the bioreactor and the microcosm were similar, but reductions in the treatment times were observed with the bioreactor experiments. An analysis of the microbial community structure by DGGE using various markers showed distinct behaviors between two treatments containing high nickel concentrations. The main conclusion of this study was that Nickel promotes a significant delay in oil biodegradation, despite having only a minor effect over the microbial community.

  9. Effects of reclamation on macrobenthic assemblages in the coastline of the Arabian Gulf: a microcosm experimental approach.

    Science.gov (United States)

    Naser, Humood A

    2011-03-01

    Coastal reclamation and modifications are extensively carried out in Bahrain, which may physically smother the coastal and subtidal habitats resulting in changes to abundance and distribution of macrobenthic assemblages. A microcosm laboratory experiment using three common macrobenthic invertebrates from a proposed reclaimed coastal area was preformed to examine their responses to mud burial using marine sediment collected from a designated borrow area. Significant difference in numbers of survived organisms between control and experimental treatments with a survival percentage of 41.8% for all of the selected species was observed. The polychaete Perinereis nuntia showed the highest percentage of survival (57.1%) followed by the bivalve Tellinavaltonis (42.3%) and the gastropod Cerithidea cingulata (24.0%). Quantifying species responses to sediment burial resulted from dredging and reclamation will aid in predicting the expected ecological impacts associated with coastal developments and subsequently minimizing these impacts and maintaining a sustainable use of coastal and marine ecosystems in the Arabian Gulf. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Impact of protists on a hydrocarbon-degrading bacterial community from deep-sea Gulf of Mexico sediments: A microcosm study

    Science.gov (United States)

    Beaudoin, David J.; Carmichael, Catherine A.; Nelson, Robert K.; Reddy, Christopher M.; Teske, Andreas P.; Edgcomb, Virginia P.

    2016-07-01

    In spite of significant advancements towards understanding the dynamics of petroleum hydrocarbon degrading microbial consortia, the impacts (direct or indirect via grazing activities) of bacterivorous protists remain largely unknown. Microcosm experiments were used to examine whether protistan grazing affects the petroleum hydrocarbon degradation capacity of a deep-sea sediment microbial community from an active Gulf of Mexico cold seep. Differences in n-alkane content between native sediment microcosms and those treated with inhibitors of eukaryotes were assessed by comprehensive two-dimensional gas chromatography following 30-90 day incubations and analysis of shifts in microbial community composition using small subunit ribosomal RNA gene clone libraries. More biodegradation was observed in microcosms supplemented with eukaryotic inhibitors. SSU rRNA gene clone libraries from oil-amended treatments revealed an increase in the number of proteobacterial clones (particularly γ-proteobacteria) after spiking sediments with diesel oil. Bacterial community composition shifted, and degradation rates increased, in treatments where protists were inhibited, suggesting protists affect the hydrocarbon degrading capacity of microbial communities in sediments collected at this Gulf of Mexico site.

  11. Tetracyclines and tetracycline resistance in agricultural soils: microcosm and field studies.

    OpenAIRE

    Schmitt, Heike; Stoob, Krispin; Hamscher, Gerd; Smit, Eric; Seinen, Willem

    2006-01-01

    The influence of the use of antibiotics on the prevalence of resistance genes in the environment is still poorly understood. We studied the diversity of tetracycline and sulfonamide resistance genes as influenced by fertilization with pig manure in soil microcosms and at two field locations. Manure contained a high diversity of resistance genes, regardless of whether it stemmed from a farm operation with low or regular use of antibiotics. In the microcosm soils, the influence of fertilization...

  12. [Exploration of microcosmic Chinese medicine used by western medicine].

    Science.gov (United States)

    Zheng, Zhi-jing

    2015-02-01

    "Microcosmic syndrome", "treatment based on syndrome differentiation", and "combination of disease identification and syndrome differentiation" generally refer to a mode: following the syndrome if with no disease identified, following the disease if with no syndrome type differentiated. For example, Chinese medical treatment of hypertension, high blood lipids, increased transaminase, and so on candirectly use Chinese recipes, but no longer with syndrome differentiation. Clinical application of Chinese patent medicine can also obtain favorable clinical. Western doctors need not follow syndrome differentiation. The invention of artemisinin was screened from more than 40 000 kinds of compounds and herbs, but with no reference of any traditional Chinese medical theory. A lot of folk remedy and empirical recipes have obtained effective efficacy but unnecessarily with profound Chinese medical theories. Various evidences showed that disease can also be cured without syndrome differentiation. I held that it might be associated with the same mechanism of Chinese medicine and Western medicine. Any disease can be cured or alleviated by Chinese medicine is a result from its modern pharmacological effect, which is achieved by improving etiologies, and pathogeneses. I was inspired by whether we can directly use traditional Chinese medicine with modern pharmacological effects to treat symptomatic disease. So I raised an idea of microcosmic Chinese medicine used by Western medicine, i.e., we find and use Chinese herbs with relatively effective modern pharmacological effect to treat diseases targeting at patients' clinical symptoms and signs, as well as various positive laboratory results (collectively called as microscopic dialectical indicators). More Western doctors would use it to treat disease due to omission of complicated and mysterious syndrome differentiation. This will promote extensive application and expansion of Chi- nese medicine and pharmacy, enlarge the team of

  13. Ecological effects of ionizing radiation and other toxic agents on the aquatic microcosm

    International Nuclear Information System (INIS)

    Fuma, Shoichi; Ishii, Nobuyoshi; Tanaka, Nobuyuki; Takeda, Hiroshi; Miyamoto, Kiriko; Yanagisawa, Kei; Kawabata, Zen'ichiro

    2004-01-01

    The purpose of this study was comparative evaluation of effects of ionizing radiation and other various toxic agents on aquatic microbial communities. For this purpose, the authors investigated effects of γ-rays, ultraviolet (UV) radiation, acidification, aluminum, manganese, nickel, copper and gadolinium on the microcosm, i.e., the experimental model ecosystem consisting of populations of the flagellate alga Euglena gracilis as a producer, the ciliate protozoan Tetrahymena thermophila as a consumer and the bacterium Eseherichia coli as a decomposer. Effects of toxic agents in the microcosm were not only direct effects but also community-level effects due to interactions among the constituting species or between organisms and toxic agents. In general, the degrees of effects observed in the microcosm could be categorized as follows: no effects; recognizable effects, i.e., decrease or increase in the cell densities of at least one species; severe effects, i.e., extinction of one or two species; and destructive effects, i.e., extinction of all species. These results were analyzed by the ecological effect index (EEI), in which differences in the cell densities between exposed and control microcosm were represented by the Euclidean distance function. A 50% effect doses for the microcosm (ED M50 ), at which the EEI became 50%, were evaluated to be 530 Gy for γ-rays, 2100 J m -2 for UV, 4100 μM for manganese, 45 μM for nickel, 110 μM for copper and 250 μM for gadolinium. (author)

  14. Laboratory experiments to test relativistic gravity

    International Nuclear Information System (INIS)

    Braginsky, V.B.; Caves, C.M.; Thorne, K.S.

    1977-01-01

    Advancing technology will soon make possible a new class of gravitation experiments: pure laboratory experiments with laboratory sources of non-Newtonian gravity and laboratory detectors. This paper proposes seven such experiments; and for each one it describes, briefly, the dominant sources of noise and the technology required. Three experiments would utilize a high-Q torque balance as the detector. They include (i) an ''Ampere-type'' experiment to measure the gravitational spin-spin coupling of two rotating bodies, (ii) a search for time changes of the gravitation constant, and (iii) a measurement of the gravity produced by magnetic stresses and energy. Three experiments would utilize a high-Q dielectric crystal as the detector. They include (i) a ''Faraday-type'' experiment to measure the ''electric-type'' gravity produced by a time-changing flux of ''magnetic-type'' gravity, (ii) a search for ''preferred-frame'' and ''preferred-orientation'' effects in gravitational coupling, and (iii) a measurement of the gravitational field produced by protons moving in a storage ring at nearly the speed of light. One experiment would use a high-Q toroidal microwave cavity as detector to search for the dragging of inertial frames by a rotating body

  15. MICROCOSM AND IN-SITU FIELD STUDIES OF ENHANCED BIOTRANSFORMATION OF TRICHLOROETHYLENE BY PHENOL-UTILIZING MICROORGANISMS

    Science.gov (United States)

    The ability of different aerobic groundwater microorganisms to cometabolically degrade trichloroethylene (TCE), 1,2-cis-dichloroethylene (c-DCE), and 1,2-trans-dichloroethylene (t-DCE) was evaluated both in groundwater-fed microcosms and in situ in a shallow aquifer. Microcosms a...

  16. Effect of concentration gradients on biodegradation in bench-scale sand columns with HYDRUS modeling of hydrocarbon transport and degradation.

    Science.gov (United States)

    Horel, Agota; Schiewer, Silke; Misra, Debasmita

    2015-09-01

    The present research investigated to what extent results obtained in small microcosm experiments can be extrapolated to larger settings with non-uniform concentrations. Microbial hydrocarbon degradation in sandy sediments was compared for column experiments versus homogenized microcosms with varying concentrations of diesel, Syntroleum, and fish biodiesel as contaminants. Syntroleum and fish biodiesel had higher degradation rates than diesel fuel. Microcosms showed significantly higher overall hydrocarbon mineralization percentages (p transport and degradation of the investigated fuels in vadose zone conditions similar to those in laboratory column experiments. The numerical model was used to evaluate the impact of different degradation rate constants from microcosm versus column experiments.

  17. Zero-gravity cloud physics laboratory: Experiment program definition and preliminary laboratory concept studies

    Science.gov (United States)

    Eaton, L. R.; Greco, E. V.

    1973-01-01

    The experiment program definition and preliminary laboratory concept studies on the zero G cloud physics laboratory are reported. This program involves the definition and development of an atmospheric cloud physics laboratory and the selection and delineations of a set of candidate experiments that must utilize the unique environment of zero gravity or near zero gravity.

  18. Effect of zinc-enriched natural sediments, in isolated and microcosm models, on three species of benthic invertebrates

    International Nuclear Information System (INIS)

    Galar Martinez, Marcela; Martinez-Tabche, Laura; Sanchez-Hidalgo, Eugenia; Lopez Lopez, Eugenia

    2006-01-01

    reservoir sediments. Therefore H. azteca maintained its constant Zn levels during the whole experiment. It is possible that the caption rate is so low in this organism that it does not need another regulatory mechanism. A decrement in ATP in worms and amphipods was observed in both systems at all exposure times. Possibly Zn and other metals present in the sediments interfere with the energy production enzymes by binding to SH groups. Nevertheless this biomolecule increased in snails in microcosms at all exposure times and in isolated systems at the end of the experiment, probably due to compensatory mechanisms and reduction in energy consumption present in mollusks during heavy metals exposure. (author) [es

  19. Persistence of selected ammonium- and phosphonium-based ionic liquids in urban park soil microcosms

    DEFF Research Database (Denmark)

    Sydow, Mateusz; Szczepaniak, Zuzanna; Framski, Grzegorz

    2015-01-01

    Knowledge about biodegradability of ionic liquids (ILs) in terrestrial systems is limited. Here, using urban park soil microcosms spiked with either ammonium- or phosphonium-based ILs [didecyldimethylammonium 3-amino-1,2,4-triazolate, benzalkonium 3-amino-1,2,4-triazolate, trihexyl(tetradecyl)pho......Knowledge about biodegradability of ionic liquids (ILs) in terrestrial systems is limited. Here, using urban park soil microcosms spiked with either ammonium- or phosphonium-based ILs [didecyldimethylammonium 3-amino-1,2,4-triazolate, benzalkonium 3-amino-1,2,4-triazolate, trihexyl......(tetradecyl)phosphonium chloride, or trihexyl(tetradecyl)phosphonium 1,2,4-triazolate], we studied their (i) 300-day primary biodegradation, and (ii) influence on CO2 evolution from the microcosms. The primary biodegradation ranged from 21 to 33% of total compound in the dissolved phase. The evolution of CO2 from spiked...... microcosms was either lower or within the range of background soil respiration, indicating no or small mineralization of the parent compounds and/or their metabolites, and their negligible or small toxicity to soil microorganisms. Our results suggest the potential for persistence of the four studied ILs...

  20. Monitoring Uranium Transformations Determined by the Evolution of Biogeochemical Processes: Design of Mixed Batch Reactor and Column Studies at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Criddle, Craig S.; Wu, Weimin

    2013-04-17

    With funds provided by the US DOE, Argonne National Laboratory subcontracted the design of batch and column studies to a Stanford University team with field experience at the ORNL IFRC, Oak Ridge, TN. The contribution of the Stanford group ended in 2011 due to budget reduction in ANL. Over the funded research period, the Stanford research team characterized ORNL IFRC groundwater and sediments and set up microcosm reactors and columns at ANL to ensure that experiments were relevant to field conditions at Oak Ridge. The results of microcosm testing demonstrated that U(VI) in sediments was reduced to U(IV) with the addition of ethanol. The reduced products were not uraninite but were instead U(IV) complexes associated with Fe. Fe(III) in solid phase was only partially reduced. The Stanford team communicated with the ANL team members through email and conference calls and face to face at the annual ERSP PI meeting and national meetings.

  1. Multidimensional Screening as a Pharmacology Laboratory Experience.

    Science.gov (United States)

    Malone, Marvin H.; And Others

    1979-01-01

    A multidimensional pharmacodynamic screening experiment that addresses drug interaction is included in the pharmacology-toxicology laboratory experience of pharmacy students at the University of the Pacific. The student handout with directions for the procedure is reproduced, drug compounds tested are listed, and laboratory evaluation results are…

  2. Inhibition of bacterial ammonia oxidation by organohydrazines in soil microcosms

    Directory of Open Access Journals (Sweden)

    Yucheng eWu

    2012-01-01

    Full Text Available Hydroxylamine oxidation by hydroxylamine oxidoreductase (HAO is a key step for energy-yielding in support of the growth of ammonia-oxidizing bacteria (AOB. Organohydrazines have been shown to inactivate HAO from Nitrosomonas europaea, and may serve as selective inhibitors to differentiate bacterial from archaeal ammonia oxidation due to the absence of bacterial HAO gene homologue in known ammonia-oxidizing archaea (AOA. In this study, the effects of three organohydrazines on activity, abundance and composition of AOB and AOA were evaluated in soil microcosms. The results indicate that phenylhydrazine and methylhydrazine at the concentration of 100 mol per gram dry weight soil completely suppressed the activity of soil nitrification. DGGE fingerprinting and sequencing analysis of bacterial ammonia monooxygenase subunit A gene (amoA clearly demonstrated that nitrification activity change is well paralleled with the growth of Nitrosomonas europaea-like AOB in soil microcosms. No significant correlation between AOA community structure and nitrification activity was observed among all treatments during the incubation period, although incomplete inhibition of nitrification activity occurred in 2-hydroxyethylhydrazine-amended soil microcosms. These findings show that the HAO-targeted organohydrazines can effectively inhibit bacterial nitrification in soil, and the mechanism of organohydrazine affecting AOA remains unclear.

  3. Azolla-anabaena-bacteria system as a natural microcosm

    Science.gov (United States)

    Carrapico, Francisco J.

    2002-02-01

    Azolla is an aquatic fern that contains a permanent endosymbiotic prokaryotic community (cyanobacteria and bacteria) inside of the cavity in the leaf dorsal lobe of the pteridophyte. This is a unique situation and can be seen as a microcosm inside of an organism and also can be considered a good example of a living model for biological and environmental studies. These symbionts are specific of this symbiosis and lives immobilized in a mucilaginous fibrillar network, which fills part of the cavity. The symbionts works as immobilized organisms in a natural system that can be used as a model for biotechnological research and in biologically based life support systems. The nature and the complexity of this system is simultaneously a reference and a challenge for the research in the communication between the two levels of nature organization (microcosm and mesocosm), and can also be used as a reference for the design of new environmental engineered symbiotic systems that include man as a prelude to life in space.

  4. Effects of the fungicide metiram in outdoor freshwater microcosms: responses of invertebrates, primany producers and microbes

    NARCIS (Netherlands)

    Ronghua, Lin; Buijse-Bogdan, L.L.; Rocha Dimitrov, M.; Dohmen, P.; Kosol, Sujitra; Maltby, L.; Roessink, I.; Sinkeldam, J.A.; Smidt, H.; Wijngaarden, van R.P.A.; Brock, T.C.M.

    2012-01-01

    The ecological impact of the dithiocarbamate fungicide metiram was studied in outdoor freshwater microcosms, consisting of 14 enclosures placed in an experimental ditch. The microcosms were treated three times (interval 7 days) with the formulated product BAS 222 28F (Polyram®). Intended metiram

  5. Ecological effects of various toxic agents on the aquatic microcosm in comparison with acute ionizing radiation

    International Nuclear Information System (INIS)

    Fuma, S.; Ishii, N.; Takeda, H.; Miyamoto, K.; Yanagisawa, K.; Ichimasa, Y.; Saito, M.; Kawabata, Z.; Polikarpov, G.G.

    2003-01-01

    The purpose of this study was an evaluation of the effect levels of various toxic agents compared with acute doses of ionizing radiation for the experimental model ecosystem, i.e., microcosm mimicking aquatic microbial communities. For this purpose, the authors used the microcosm consisting of populations of the flagellate alga Euglena gracilis as a producer, the ciliate protozoan Tetrahymena thermophila as a consumer and the bacterium Escherichia coli as a decomposer. Effects of aluminum and copper on the microcosm were investigated in this study, while effects of γ-rays, ultraviolet radiation, acidification, manganese, nickel and gadolinium were reported in previous studies. The microcosm could detect not only the direct effects of these agents but also the community-level effects due to the interspecies interactions or the interactions between organisms and toxic agents. The authors evaluated doses or concentrations of each toxic agent which had the following effects on the microcosm: (1) no effects; (2) recognizable effects, i.e., decrease or increase in the cell densities of at least one species; (3) severe effects, i.e., extinction of one or two species; and (4) destructive effects, i.e., extinction of all species. The resulting effects data will contribute to an ecological risk assessment of the toxic agents compared with acute doses of ionizing radiation

  6. Laboratory Experiments on Low-crested Breakwaters

    DEFF Research Database (Denmark)

    Kramer, Morten; Zanuttigh, B.; van der Meer, J.W.

    2005-01-01

    New unique laboratory experiments on low-crested structures (LCSs) have been performed within the DELOS project. The experiments were carried out in three European laboratories aiming at extending and completing existing available information with respect to a wide range of engineering design...... in a wave channel at small scale, and scale effects regarding wave transmission and reflection were studied in a wave channel at a large scale facility. The paper describes the experiments and associated databank with respect to objectives, test program, set-ups and measurements. Results, guidelines...... and recommendations elaborated from the tests are included in the other companion papers of the Coastal Engineering Special Issue on DELOS....

  7. Relationship between hydrocarbon measurements and toxicity to a chironomid, fish larva and daphnid for oils and oil spill chemical treatments in laboratory freshwater marsh microcosms

    International Nuclear Information System (INIS)

    Klerks, Paul L.; Nyman, John A.; Bhattacharyya, S.

    2004-01-01

    This research investigated the extent to which various common hydrocarbon measures can be used to predict toxicity to freshwater aquatic organisms due to fouling by oil. Actual toxicity results, on laboratory freshwater marsh microcosms using two water-column species and a benthic species, were described earlier. The hydrocarbon measures used were TPH g , TPH FID , TPH MS , TTAH (sum of 41 target aromatic hydrocarbons), principal components of 41 TAHs, and each individual TAH. In general, toxicity was more closely related to TPH MS levels than to TPH FID and (especially) TPH g levels. The strongest relationships were found for TTAH levels and for the principal components of the TAHs. Regressions of toxicity on many individual TAHs were also strong, with a single group of compounds explaining as much as 59% of the variation in survival. While the various regressions were highly significant statistically and at times able to accurately predict broad differences in toxicity, the high variation in survival at a specific hydrocarbon concentration indicates that these hydrocarbon measures can not substitute for actual toxicity determinations in accurately ranking the toxicity of samples from oiled freshwater marshes. - Hydrocarbon measurements cannot be substituted for actual toxicity determinations

  8. Effects of acute {gamma}-irradiation on community structure of the aquatic microbial microcosm

    Energy Technology Data Exchange (ETDEWEB)

    Fuma, Shoichi, E-mail: fuma@nirs.go.j [Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Ishii, Nobuyoshi; Takeda, Hiroshi [Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Doi, Kazutaka; Kawaguchi, Isao [Regulatory Sciences Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shikano, Shuichi [Center for Northeast Asian Studies, Tohoku University, 41 Kawauchi, Aoba-ku, Sendai, Miyagi 980-8576 (Japan); Tanaka, Nobuyuki [Marine Environment Section, Water and Soil Environment Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Inamori, Yuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan)

    2010-11-15

    To characterise indirect effects of ionising radiation on aquatic microbial communities, effects of acute {gamma}-irradiation were investigated in a microcosm consisting of populations of green algae (Chlorella sp. and Scenedesmus sp.) and a blue-green alga (Tolypothrix sp.) as producer; a ciliate protozoan (Cyclidium glaucoma), rotifers (Lecane sp. and Philodina sp.) and an oligochaete (Aeolosoma hemprichi) as consumer; and more than four species of bacteria as decomposers. Population changes in the constituent organisms were observed over 160 days after irradiation. Prokaryotic community structure was also examined by denaturing gradient gel electrophoresis (DGGE) of 16S rDNA. Principle response curve analysis revealed that the populations of the microcosm as a whole were not significantly affected at 100 Gy while they were adversely affected at 500-5000 Gy in a dose-dependent manner. However, some effects on each population, including each bacterial population detected by DGGE, did not depend on radiation doses, and some populations in the irradiated microcosm were larger than those of the control. These unexpected results are regarded as indirect effects through interspecies interactions, and possible mechanisms are proposed originating from population changes in other organisms co-existing in the microcosm. For example, some indirect effects on consumers and decomposers likely arose from interspecies competition within each trophic level. It is also likely that prey-predator relationships between producers and consumers caused some indirect effects on producers.

  9. Transfers and transformations of zinc in flow-through wetland microcosms.

    Science.gov (United States)

    Gillespie, W B; Hawkins, W B; Rodgers, J H; Cano, M L; Dorn, P B

    1999-06-01

    Two microcosm-scale wetlands (570-liter containers) were integratively designed and constructed to investigate transfers and transformations of zinc associated with an aqueous matrix, and to provide future design parameters for pilot-scale constructed wetlands. The fundamental design of these wetland microcosms was based on biogeochemical principles regulating fate and transformations of zinc (pH, redox, etc.). Each wetland consisted of a 45-cm hydrosoil depth inundated with 25 cm of water, and planted with Scirpus californicus. Zinc ( approximately 2 mg/liter) as ZnCl2 was amended to each wetland for 62 days. Individual wetland hydraulic retention times (HRT) were approximately 24 h. Total recoverable zinc was measured daily in microcosm inflow and outflows, and zinc concentrations in hydrosoil and S. californicus tissue were measured pre- and post-treatment. Ceriodaphnia dubia and Pimephales promelas7-day aqueous toxicity tests were performed on wetland inflows and outflows, and Hyalella azteca whole sediment toxicity tests (10-day) were performed pre- and post-treatment. Approximately 75% of total recoverable zinc was transferred from the water column. Toxicity decreased from inflow to outflow based on 7-day C. dubia tests, and survival of H. azteca in hydrosoil was >80%. Data illustrate the ability of integratively designed wetlands to transfer and sequester zinc from the water column while concomitantly decreasing associated toxicity. Copyright 1999 Academic Press.

  10. Interactions among buffelgrass, phenanthrene and phenanthrene-degrading bacteria in gnotobiotic microcosms.

    Science.gov (United States)

    Robert, Francoise M; Sun, Wenhao H; Toma, Marisa; Jones, Ryan K; Tang, Chung-Shih

    2008-07-15

    An experiment was undertaken in gnotobiotic microcosms to determine the role of buffelgrass (Cenchrus ciliaris) and a phenanthrene-degrading bacterium (strain PM600) in the degradation of phenanthrene. The Gram-negative bacterium was identified as a Sphingomonas sp. by 16S rRNA gene sequence analysis and as S. paucimobilis by biochemical tests (API 20 NE strips). Its yellow pigment corresponded to nostoxanthin and its cellular fatty acids were typical of the genus Sphingomonas. Moreover, it was devoid of lipopolysaccharides. Strain PM600 was tested for growth on mineral medium supplemented with No. 2 diesel, hexadecane, mineral oil, pristane, phenanthrene, and pyrene as single carbon sources. It was capable of utilizing phenanthrene only. In the gnotobiotic microcosms silica sand was either or not supplemented with 150 mg of phenanthrene kg(-1) sand, inoculated with strain PM600, and planted to sterile young seedlings of buffelgrass. After 28 days, 67% of the reduction of the phenanthrene concentration was assigned to degradation by the bacterium and ca. 20% to abiotic factors. No statistically significant effect of the young buffelgrass was found. In the absence of phenanthrene, the bacterial population significantly increased in the rhizosphere of buffelgrass. However, in the presence of buffelgrass and phenanthrene, the bacterial population preferentially responded to phenanthrene. The growth of buffelgrass was severely curtailed by phenanthrene in the absence of the bacterium. However, strain PM600 effectively protected buffelgrass against the phytotoxicity of phenanthrene.

  11. Environmental effect and fate of selected phenols in aquatic ecosystems using microcosm approaches

    International Nuclear Information System (INIS)

    Portier, R.J.; Chen, H.M.; Meyers, S.P.

    1983-01-01

    Microbiological studies, together with physicochemical analyses of selected industrial source phenols of environmental significance, were conducted in continuous flow and carbon metabolism microcosms to determine the behavior of these priority pollutants in soil and sediment-water systems typical of coastal wetlands. Phenols used included 4- nitrophenol, 2,4,6-trichlorophenol, 2-chlorophenol, and phenol. The organophosphate, 14 C-UL-Methyl Parathion, was used as a benchmark toxicant control while 14 C-Ring-Phenol was employed for all phenolic compound additions. Microbial diversity, ATP, and specific enzyme systems (i.e., phosphatase, dehydrogenase) were continuously monitored along with 14 CO 2 expiration and 14 C assimilation by the cellular component. Residual analysis of all microcosm tests employed procedures using combined gas chromatography/high-performance liquid chromatography. Statistical analyses were conducted of variations of testing criteria, along with a ranking profile of relative biotransformation and biodegradation potential. Data presented confirm the validity of microcosm approaches and related correlation analysis in toxic substance fate investigations. 17 references, 6 figures, 1 table

  12. Project-Based Laboratory Experiences in Mechanical Engineering

    Directory of Open Access Journals (Sweden)

    Narendra Sharma

    2011-12-01

    Full Text Available In this paper we describe project-based laboratories in Mechanical Engineering designed to provide semester-long team experiences which mimic the real life industrial processes of design, development, testing and optimization. The labs are focused on courses at the sophomore level and thus require special attention to constraints of student backgrounds and experience. This paper describes laboratory projects in Dynamics and Fluid Mechanics.

  13. Lakes and rivers as microcosms, version 2.0

    Directory of Open Access Journals (Sweden)

    David G. Jenkins

    2013-08-01

    Full Text Available Limnology has been greatly influenced by The Lake as a Microcosm (Forbes, 1887, which described a holistic focus on the internal machinations of singular, island-like aquatic ecosystems. I consider three persistent influences of The Lake as a Microcosm: as an organizing paradigm for the teaching of limnology relative to its practice; the idea that inland waters are like islands, and the replicability of types of inland waters. Based on inspection of recent peer-reviewed literature and 32 limnology texts, we teach limnology according to Forbes but do not practice it in that holistic context. Instead, we practice limnology as aquatic ecology. Based on novel analyses of species-area relationships for 275 inland waters and 392 islands, inland waters are more like continental habitat patches than islands; the island metaphor is poetic but not accurate. Based on a quantitative review of beta diversity (40 data sets representing 10,576 inland waters and 26 data sets representing 1529 terrestrial sites, aquatic systems are no more replicable than are terrestrial systems; a typological approach to limnology is no more justified than it is in terrestrial systems. I conclude that a former distinction between limnology and aquatic ecology no longer applies, and that we should define limnology as the ecology of inland waters. Also, we should not consider lakes and rivers as islands that represent other systems of the same type, but should consider them as open, interactive habitat patches that vary according to their geology and biogeography. I suggest modern limnology operates according to 3 paradigms, which combine to form 3 broad limnological disciplines and establish a basis for a plural, interactive view of lakes and rivers as microcosms. This model of modern limnology may help better connect it to ecology and biogeography and help limnology be even more relevant to science and society.

  14. In situ and laboratory studies on the fate of specific organic compounds in an anaerobic landfill leachate plume, 1. Experimental conditions and fate of phenolic compounds

    Science.gov (United States)

    Nielsen, Per H.; Albrechtsen, Hans-Jørgen; Heron, Gorm; Christensen, Thomas H.

    1995-11-01

    The transformation of specific organic compounds was investigated by in situ and laboratory experiments in an anaerobic landfill leachate pollution plume at four different distances from the landfill. This paper presents the experimental conditions in the in situ microcosm and laboratory batch microcosm experiments performed and the results on the fate of 7 phenolic compounds. Part 2 of this series of papers, also published in this issue, presents the results on the fate of 8 aromatic compounds and 4 chlorinated aliphatic compounds. The redox conditions in the plume were characterized as methanogenic, Fe(III)-reducing and NO 3--reducing by the redox sensitive species present in groundwater and sediment and by bioassays. With a few exceptions the aquifer redox conditions were maintained throughout the experiments as monitored by redox sensitive species present in groundwater during the experiments, by redox sensitive species present in the sediment after the experiments and by bioassays performed after the experiments. Transformation of nitrophenol was very fast close to the landfill in strongly reducing conditions, while transformation was slower in the more oxidized part of the plume. Lag phases for the nitrophenols were short (maximum 10 days). Phenol was only transformed in the more distant part of the plume in experiments where NO 3-, Fe(III) and Mn(IV) reduction was dominant. Lag phases for phenol were either absent or lasted up to 2 months. Dichlorophenols were only transformed in experiments representing strongly reducing, presumably methanogenic, redox conditions close to the landfill after lag phases of up to 3 months. Transformation of o-cresol was not observed in any of the experiments throughout the plume. Generally, there was good accordance between the results obtained by in situ and laboratory experiments, both concerning redox conditions and the fate of the phenolic compounds. However, for phenol and 2,4-dichlorophenol, transformation was observed

  15. Biodegradation of weathered polystyrene films in seawater microcosms.

    Science.gov (United States)

    Syranidou, Evdokia; Karkanorachaki, Katerina; Amorotti, Filippo; Franchini, Martina; Repouskou, Eftychia; Kaliva, Maria; Vamvakaki, Maria; Kolvenbach, Boris; Fava, Fabio; Corvini, Philippe F-X; Kalogerakis, Nicolas

    2017-12-21

    A microcosm experiment was conducted at two phases in order to investigate the ability of indigenous consortia alone or bioaugmented to degrade weathered polystyrene (PS) films under simulated marine conditions. Viable populations were developed on PS surfaces in a time dependent way towards convergent biofilm communities, enriched with hydrocarbon and xenobiotics degradation genes. Members of Alphaproteobacteria and Gammaproteobacteria were highly enriched in the acclimated plastic associated assemblages while the abundance of plastic associated genera was significantly increased in the acclimated indigenous communities. Both tailored consortia efficiently reduced the weight of PS films. Concerning the molecular weight distribution, a decrease in the number-average molecular weight of films subjected to microbial treatment was observed. Moreover, alteration in the intensity of functional groups was noticed with Fourier transform infrared spectrophotometry (FTIR) along with signs of bio-erosion on the PS surface. The results suggest that acclimated marine populations are capable of degrading weathered PS pieces.

  16. Effects of Lactobacillus rhamnosus GG on saliva-derived microcosms

    NARCIS (Netherlands)

    Pham, L.C.; Hoogenkamp, M.A.; Exterkate, R.A.M.; Terefework, Z.; de Soet, J.J.; ten Cate, J.M.; Crielaard, W.; Zaura, E.

    2011-01-01

    Objective The probiotic strain Lactobacillus rhamnosus GG (LGG) is shown to hamper the presence of mutans streptococci in saliva and may have positive effects on oral health. We investigated the effects of LGG on the cariogenic potential and microbial composition of saliva-derived microcosms. Design

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

    NARCIS (Netherlands)

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

    2004-01-01

    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

  18. Making Sparklers: An Introductory Laboratory Experiment

    Science.gov (United States)

    Keeney, Allen; Walters, Christina; Cornelius, Richard D.

    1995-07-01

    A laboratory experiment consisting of the preparation of sparklers has been developed as part of a project which organizes the general chemistry sequence according to subjects with which students are familiar. This laboratory makes use of oxidation/reduction chemistry to produce a product familiar to students. The result is a mixture rather than a compound, but the composition must be carefully measured to produce a sparkler that will stay lit and produce sparks. The dramatic reaction may be the most impressive and memorable experience that students encounter in the laboratory. Sparklers are formulated from iron, magnesium, and aluminum powders, plus potassium chlorate and barium nitrate held on thick iron wire by a starch paste. At elevated temperatures metal nitrates and chlorates decompose to produces gases, providing the necessary force to eject bits of powdered, burning metal into the air.

  19. This summer, go behind-the-scenes of CERN in photos in the Microcosm

    CERN Multimedia

    2016-01-01

    Find out the best photos of the 2015 CERN Photowalk competition in the Microcosm.   Photo: Olivier Miche. The best photos taken at the 2015 CERN Photowalk competition are now exhibited in the Microcosm, for the whole summer period. Through this photographic exhibition, the visitors will be taken behind-the scenes of CERN, through the main workshop, the ISOLDE facility and the future accelerator Linac 4. They will also take a glimpse of the life on the CERN campus.

  20. Laboratory Experiments and their Applicability

    OpenAIRE

    Steinhaus, Thomas; Jahn, Wolfram

    2007-01-01

    In conjunction with the Dalmarnock Fire Tests a series of laboratory tests have been conducted at the BRE Centre for Fire Safety Engineering at the University of Edinburgh (UoE) in support of the large scale tests. These were conducted prior to and post the tests in Dalmarnock. Before the tests, ignition experiments were carried out in the laboratory to ensure flame spread from the wastepaper basket to the sofa. The later series of lab tests comprised of small scale cone calori...

  1. Experimental microcosm study of the effects of Deepwater Horizon MC-252 oil on the geochemistry and microbiology of Gulf Coast sediment

    Science.gov (United States)

    Donahoe, R. J.; Bej, A.; Raulerson, A.; Rentschler, E. K.

    2011-12-01

    Microcosm experiments were conducted to examine the impact of oil contamination on Gulf Coast sediment geochemistry and microbial population dynamics. Coastal sediment and seawater were collected from a salt marsh at Bayou la Batre, Alabama, which was not severely impacted by the BP Deepwater Horizon accident of April 2010. Sediment/seawater microcosms were set up in glass jars combusted for 5 hours at 450 degrees C. Non-sterile microcosms spiked with 500 ppm of MC-252 oil were sacrificed in duplicate at various time intervals over a 14 day period to establish a data time series. Sterile controls with and without oil and a non-sterile control without oil were sacrificed in duplicate at 14 days for comparison with the time-series experiments. Solid and aqueous phases were separated by centrifugation and prepared for analysis. Sediment mineralogy was determined using X-ray diffraction and acid-extractable sediment chemistry determined using EPA Method 3051A and ICP-OES analysis. The aqueous phase chemistry was analyzed by ICP-OES and ion chromatography. The mineralogy of the salt marsh sediment is predominantly quartz, but includes reactive phases such as clays (smectite, illite), feldspar, and iron oxide. Iron-bearing clays and iron oxides can serve as electron acceptors for the growth of Fe(III)-reducing bacteria. Microwave digestions of the microcosm substrate samples were performed in triplicate and show no significant variation in major element chemistry over the course of the two week experiment, suggesting that observed temporal trends in aqueous geochemistry may be due to ion exchange processes, rather than mineral dissolution reactions. Microcosm substrate trace element data which indicate possible differences with time are being analyzed for statistical significance. Analysis of aqueous solution geochemistry reveals several interesting temporal trends. Iron and manganese were released to solution after 2 days, suggesting the presence of facultative

  2. Evaluation of terrestrial microcosms for detection, fate, and survival analysis of genetically engineered microorganisms and their recombinant genetic material

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, J.K.; Seidler, R.J.

    1989-02-01

    The research included in this document represents the current scientific information available regarding the applicability of terrestrial microcosms and related methodologies for evaluating detection methods and the fate and survival of microorganisms in the environment. The three terrestrial microcosms described in this document were used to evaluate the survival and fate of recombinant bacteria in soils and in association with plant surfaces and insects and their transport through soil with percolating water and root systems, and to test new methods and procedures to improve detection and enumeration of bacteria in soil. Simple (potting soil composed of peat mix and perlite, lacking environmental control and monitoring) and complex microcosms (agricultural soil with partial control and monitoring of environmental conditions) were demonstrated to be useful tools for preliminary assessments of microbial viability in terrestrial ecosystems. These studies evaluated the survival patterns of Enterobacter cloacae (pBR322) in soil and on plant surfaces and the ingestion of this same microorganism by cutworms and survival in the foregut and frass. The Versacore microcosm design was used to monitor the fate and competitiveness of genetically engineered bacteria in soil. Both selective media and gene probes were used successfully to follow the fate of two recombinant Pseudomonas sp. introduced into Versacore microcosms. Intact soil-core microcosms were employed to evaluate the fate and transport of genetically altered Azospirillum sp. and Pseudomonas sp. in soil and the plant rhizosphere. The usefulness of these various microcosms as a tool for risk assessment is underscored by the ease in obtaining soil from a proposed field release site to evaluate subsequent GEM fate and survival.

  3. Effects of chlorpyrifos in freshwater model ecosystems: the influence of experimental conditions on ecotoxicological thresholds

    NARCIS (Netherlands)

    Wijngaarden, van R.P.A.; Brock, T.C.M.; Douglas, M.T.

    2005-01-01

    Three experiments were conducted to determine the impact of the insecticide chlorpyrifos (single applications of 0.01 to 10 µg AI litre-1) in plankton-dominated nutrient-rich microcosms. The microcosms (water volume approximately 14 litres) were established in the laboratory under temperature, light

  4. A novel baiting microcosm approach used to identify the bacterial community associated with Penicillium bilaii hyphae in soil.

    Directory of Open Access Journals (Sweden)

    Behnoushsadat Ghodsalavi

    Full Text Available It is important to identify and recover bacteria associating with fungi under natural soil conditions to enable eco-physiological studies, and to facilitate the use of bacterial-fungal consortia in environmental biotechnology. We have developed a novel type of baiting microcosm, where fungal hyphae interact with bacteria under close-to-natural soil conditions; an advantage compared to model systems that determine fungal influences on bacterial communities in laboratory media. In the current approach, the hyphae are placed on a solid support, which enables the recovery of hyphae with associated bacteria in contrast to model systems that compare bulk soil and mycosphere soil. We used the baiting microcosm approach to determine, for the first time, the composition of the bacterial community associating in the soil with hyphae of the phosphate-solubilizer, Penicillium bilaii. By applying a cultivation-independent 16S rRNA gene-targeted amplicon sequencing approach, we found a hypha-associated bacterial community with low diversity compared to the bulk soil community and exhibiting massive dominance of Burkholderia OTUs. Burkholderia is known be abundant in soil environments affected by fungi, but the discovery of this massive dominance among bacteria firmly associating with hyphae in soil is novel and made possible by the current bait approach.

  5. Critical experiments at Sandia National Laboratories

    International Nuclear Information System (INIS)

    Harms, G.A.; Ford, J.T.; Barber, A.D.

    2011-01-01

    Sandia National Laboratories (SNL) has conducted radiation effects testing for the Department of Energy (DOE) and other contractors supporting the DOE since the 1960's. Over this period, the research reactor facilities at Sandia have had a primary mission to provide appropriate nuclear radiation environments for radiation testing and qualification of electronic components and other devices. The current generation of reactors includes the Annular Core Research Reactor (ACRR), a water-moderated pool-type reactor, fueled by elements constructed from UO2-BeO ceramic fuel pellets, and the Sandia Pulse Reactor III (SPR-III), a bare metal fast burst reactor utilizing a uranium-molybdenum alloy fuel. The SPR-III is currently defueled. The SPR Facility (SPRF) has hosted a series of critical experiments. A purpose-built critical experiment was first operated at the SPRF in the late 1980's. This experiment, called the Space Nuclear Thermal Propulsion Critical Experiment (CX), was designed to explore the reactor physics of a nuclear thermal rocket motor. This experiment was fueled with highly-enriched uranium carbide fuel in annular water-moderated fuel elements. The experiment program was completed and the fuel for the experiment was moved off-site. A second critical experiment, the Burnup Credit Critical Experiment (BUCCX) was operated at Sandia in 2002. The critical assembly for this experiment was based on the assembly used in the CX modified to accommodate low-enriched pin-type fuel in water moderator. This experiment was designed as a platform in which the reactivity effects of specific fission product poisons could be measured. Experiments were carried out on rhodium, an important fission product poison. The fuel and assembly hardware for the BUCCX remains at Sandia and is available for future experimentation. The critical experiment currently in operation at the SPRF is the Seven Percent Critical Experiment (7uPCX). This experiment is designed to provide benchmark

  6. Critical experiments at Sandia National Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Harms, G.A.; Ford, J.T.; Barber, A.D., E-mail: gaharms@sandia.gov [Sandia National Laboratories, Albuquerque, NM (United States)

    2011-07-01

    Sandia National Laboratories (SNL) has conducted radiation effects testing for the Department of Energy (DOE) and other contractors supporting the DOE since the 1960's. Over this period, the research reactor facilities at Sandia have had a primary mission to provide appropriate nuclear radiation environments for radiation testing and qualification of electronic components and other devices. The current generation of reactors includes the Annular Core Research Reactor (ACRR), a water-moderated pool-type reactor, fueled by elements constructed from UO2-BeO ceramic fuel pellets, and the Sandia Pulse Reactor III (SPR-III), a bare metal fast burst reactor utilizing a uranium-molybdenum alloy fuel. The SPR-III is currently defueled. The SPR Facility (SPRF) has hosted a series of critical experiments. A purpose-built critical experiment was first operated at the SPRF in the late 1980's. This experiment, called the Space Nuclear Thermal Propulsion Critical Experiment (CX), was designed to explore the reactor physics of a nuclear thermal rocket motor. This experiment was fueled with highly-enriched uranium carbide fuel in annular water-moderated fuel elements. The experiment program was completed and the fuel for the experiment was moved off-site. A second critical experiment, the Burnup Credit Critical Experiment (BUCCX) was operated at Sandia in 2002. The critical assembly for this experiment was based on the assembly used in the CX modified to accommodate low-enriched pin-type fuel in water moderator. This experiment was designed as a platform in which the reactivity effects of specific fission product poisons could be measured. Experiments were carried out on rhodium, an important fission product poison. The fuel and assembly hardware for the BUCCX remains at Sandia and is available for future experimentation. The critical experiment currently in operation at the SPRF is the Seven Percent Critical Experiment (7uPCX). This experiment is designed to provide

  7. Effect of vegetation removal and water table drawdown on the non-methane biogenic volatile organic compound emissions in boreal peatland microcosms

    Science.gov (United States)

    Faubert, Patrick; Tiiva, Päivi; Rinnan, Åsmund; Räty, Sanna; Holopainen, Jarmo K.; Holopainen, Toini; Rinnan, Riikka

    2010-11-01

    Biogenic volatile organic compound (BVOC) emissions are important in the global atmospheric chemistry and their feedbacks to global warming are uncertain. Global warming is expected to trigger vegetation changes and water table drawdown in boreal peatlands, such changes have only been investigated on isoprene emission but never on other BVOCs. We aimed at distinguishing the BVOCs released from vascular plants, mosses and peat in hummocks (dry microsites) and hollows (wet microsites) of boreal peatland microcosms maintained in growth chambers. We also assessed the effect of water table drawdown (-20 cm) on the BVOC emissions in hollow microcosms. BVOC emissions were measured from peat samples underneath the moss surface after the 7-week-long experiment to investigate whether the potential effects of vegetation and water table drawdown were shown. BVOCs were sampled using a conventional chamber method, collected on adsorbent and analyzed with GC-MS. In hummock microcosms, vascular plants increased the monoterpene emissions compared with the treatment where all above-ground vegetation was removed while no effect was detected on the sesquiterpenes, other reactive VOCs (ORVOCs) and other VOCs. Peat layer from underneath the surface with intact vegetation had the highest sesquiterpene emissions. In hollow microcosms, intact vegetation had the highest sesquiterpene emissions. Water table drawdown decreased monoterpene and other VOC emissions. Specific compounds could be closely associated to the natural/lowered water tables. Peat layer from underneath the surface of hollows with intact vegetation had the highest emissions of monoterpenes, sesquiterpenes and ORVOCs whereas water table drawdown decreased those emissions. The results suggest that global warming would change the BVOC emission mixtures from boreal peatlands following changes in vegetation composition and water table drawdown.

  8. Microcosm investigation on phytoremediation of Cr using Azolla pinnata.

    Science.gov (United States)

    Rai, Prabhat Kumar

    2010-01-01

    The extent of Chromium (Cr) pollution in Singrauli industrial region, India was assessed and phytoremediation capacity of a small water fern, Azolla pinnata R.BR (Azollaceae) was observed to purify waters polluted by Cr under microcosm condition. Azolla pinnata endemic to India is a potential hyper-accumulator of heavy metals. During 13 days of the experiment the fern was grown in the aqueous medium containing Cr3+ and CrO4(2-) ions, each in a concentration 0.5, 1.0, and 3.0 mg L(-1). The presence of these ions caused a + 3.1 to -37.5% inhibition of Azolla pinnata growth in comparison to the control. After 13 days of the experiment, metal contents in the solution was decreased up to 70% (CrO4(2-) 3.0 mg L(-1) treatment) to 88% (CrO4(2-) 0.5 mg L(-1) treatment). In the Azolla pinnata tissues, the concentration of couple of the ionic forms of Cr under investigation ranged from 415 to 1095 mg kg(-1) dry mass (dm); the highest level being found for Cr (III) containing solution.

  9. Chromium Resistant Bacteria: Impact on Plant Growth in Soil Microcosm

    Directory of Open Access Journals (Sweden)

    Sayel Hanane

    2014-07-01

    Full Text Available Three chromium resistant bacterial strains, Pseudomonas fluorescens PF28, Enterobacter amnigenus EA31 and Enterococcus gallinarum S34 isolated from tannery waste contaminated soil were used in this study. All strains could resist a high concentration of K2Cr2O7 that is up to 300 mg/L. The effect of these strains on clover plants (Trifolium campestre in the presence of two chromium salts CrCl3 and K2Cr2O7 was studied in soil microcosm. Application of chromium salts adversely affected seed germination, root and shoot length. Bacterial inoculation improved the growth parameters under chromate stress when compared with non inoculated respective controls. There was observed more than 50% reduction of Cr(VI in inoculated soil microcosms, as compared to the uninoculated soil under the same conditions. The results obtained in this study are significant for the bioremediation of chromate pollution.

  10. A Kinetic Experiment for the Biochemistry Laboratory.

    Science.gov (United States)

    Palmer, Richard E.

    1986-01-01

    Discusses the use of specific reactions of metabolic pathways to make measurements in the laboratory. Describes an adaptation of an experiment used in undergraduate biochemistry laboratories involving the induction of an enzyme in E. coli, as well as its partial purification and characterization. (TW)

  11. Raising environmental awareness through applied biochemistry laboratory experiments.

    Science.gov (United States)

    Salman Ashraf, S

    2013-01-01

    Our environment is under constant pressure and threat from various sources of pollution. Science students, in particular chemistry students, must not only be made aware of these issues, but also be taught that chemistry (and science) can provide solutions to such real-life issues. To this end, a newly developed biochemistry laboratory experiment is described that guides students to learn about the applicability of peroxidase enzymes to degrade organic dyes (as model pollutants) in simulated waste water. In addition to showing how enzymes can potentially be used for waste water remediation, various factors than can affect enzyme-based reactions such as pH, temperature, concentration of substrates/enzymes, and denaturants can also be tested. This "applied biotechnology" experiment was successfully implemented in an undergraduate biochemistry laboratory course to enhance students' learning of environmental issues as well important biochemistry concepts. Student survey confirmed that this laboratory experiment was successful in achieving the objectives of raising environmental awareness in students and illustrating the usefulness of chemistry in solving real-life problems. This experiment can be easily adopted in an introductory biochemistry laboratory course and taught as an inquiry-guided exercise. © 2013 by The International Union of Biochemistry and Molecular Biology.

  12. Concurrent nitrate and Fe(III) reduction during anaerobic biodegradation of phenols in a sandstone aquifer

    DEFF Research Database (Denmark)

    Broholm, Mette; Crouzet, C.; Arvin, Erik

    2000-01-01

    The biodegradation of phenols (similar to 5, 60, 600 mg 1(-1)) under anaerobic conditions (nitrate enriched and unamended) was studied in laboratory microcosms with sandstone material and groundwater from within an anaerobic ammonium plume in an aquifer, The aqueous phase was sampled and analyzed...... for phenols and selected redox sensitive parameters on a regular basis. An experiment with sandstone material from specific depth intervals from a vertical profile across the ammonium plume was also conducted. The miniature microcosms used in this experiment were sacrificed for sampling for phenols...... and selected redox sensitive parameters at the end of the experiment. The sandstone material was characterized with respect to oxidation and reduction potential and Fe(II) and Fe(III) speciation prior to use for all microcosms and at the end of the experiments for selected microcosms. The redox conditions...

  13. Habitat Complexity in Aquatic Microcosms Affects Processes Driven by Detritivores.

    Directory of Open Access Journals (Sweden)

    Lorea Flores

    Full Text Available Habitat complexity can influence predation rates (e.g. by providing refuge but other ecosystem processes and species interactions might also be modulated by the properties of habitat structure. Here, we focussed on how complexity of artificial habitat (plastic plants, in microcosms, influenced short-term processes driven by three aquatic detritivores. The effects of habitat complexity on leaf decomposition, production of fine organic matter and pH levels were explored by measuring complexity in three ways: 1. as the presence vs. absence of habitat structure; 2. as the amount of structure (3 or 4.5 g of plastic plants; and 3. as the spatial configuration of structures (measured as fractal dimension. The experiment also addressed potential interactions among the consumers by running all possible species combinations. In the experimental microcosms, habitat complexity influenced how species performed, especially when comparing structure present vs. structure absent. Treatments with structure showed higher fine particulate matter production and lower pH compared to treatments without structures and this was probably due to higher digestion and respiration when structures were present. When we explored the effects of the different complexity levels, we found that the amount of structure added explained more than the fractal dimension of the structures. We give a detailed overview of the experimental design, statistical models and R codes, because our statistical analysis can be applied to other study systems (and disciplines such as restoration ecology. We further make suggestions of how to optimise statistical power when artificially assembling, and analysing, 'habitat complexity' by not confounding complexity with the amount of structure added. In summary, this study highlights the importance of habitat complexity for energy flow and the maintenance of ecosystem processes in aquatic ecosystems.

  14. Development, Evaluation and Use of a Student Experience Survey in Undergraduate Science Laboratories: The Advancing Science by Enhancing Learning in the Laboratory Student Laboratory Learning Experience Survey

    Science.gov (United States)

    Barrie, Simon C.; Bucat, Robert B.; Buntine, Mark A.; Burke da Silva, Karen; Crisp, Geoffrey T.; George, Adrian V.; Jamie, Ian M.; Kable, Scott H.; Lim, Kieran F.; Pyke, Simon M.; Read, Justin R.; Sharma, Manjula D.; Yeung, Alexandra

    2015-07-01

    Student experience surveys have become increasingly popular to probe various aspects of processes and outcomes in higher education, such as measuring student perceptions of the learning environment and identifying aspects that could be improved. This paper reports on a particular survey for evaluating individual experiments that has been developed over some 15 years as part of a large national Australian study pertaining to the area of undergraduate laboratories-Advancing Science by Enhancing Learning in the Laboratory. This paper reports on the development of the survey instrument and the evaluation of the survey using student responses to experiments from different institutions in Australia, New Zealand and the USA. A total of 3153 student responses have been analysed using factor analysis. Three factors, motivation, assessment and resources, have been identified as contributing to improved student attitudes to laboratory activities. A central focus of the survey is to provide feedback to practitioners to iteratively improve experiments. Implications for practitioners and researchers are also discussed.

  15. Laboratory Experiments on Low-crested Breakwaters

    DEFF Research Database (Denmark)

    Kramer, Morten Mejlhede; Zanuttigh, B.; van der Meer, J. W.

    2004-01-01

    The ducument describe 3D tests at scale 1:20 performed in the Laboratory at Department of Civil Engineering, Aalborg University.The wave obliquity was one of the main parameters, which were studied in the wave basin experiments. The experiments provide unique information about the influences...... of this parameter where almost no research has been done before....

  16. The ATLAS Experiment Laboratory - Overview

    International Nuclear Information System (INIS)

    Malecki, P.

    1999-01-01

    Full text: ATLAS Experiment Laboratory has been created by physicists and engineers preparing a research programme and detector for the LHC collider. This group is greatly supported by members of other Departments taking also part (often full time) in the ATLAS project. These are: J. Blocki, J. Godlewski, Z. Hajduk, P. Kapusta, B. Kisielewski, W. Ostrowicz, E. Richter-Was, and M. Turala. Our ATLAS Laboratory realizes its programme in very close collaboration with the Faculty of Physics and Nuclear Technology of the University of Mining and Metallurgy. ATLAS, A Toroidal LHC ApparatuS Collaboration groups about 1700 experimentalists from about 150 research institutes. This apparatus, a huge system of many detectors, which are technologically very advanced, is going to be ready by 2005. With the start of the 2 x 7 TeV LHC collider ATLAS and CMS (the sister experiment at LHC) will begin their fascinating research programme at beam energies and intensities which have never been exploited. (author)

  17. CSI flight experiment projects of the Naval Research Laboratory

    Science.gov (United States)

    Fisher, Shalom

    1993-02-01

    The Naval Research Laboratory (NRL) is involved in an active program of CSI flight experiments. The first CSI flight experiment of the Naval Research Laboratory, the Low Power Atmospheric Compensation Experiment (LACE) dynamics experiment, has successfully measured vibrations of an orbiting satellite with a ground-based laser radar. The observations, made on January 7, 8 and 10, 1991, represent the first ever measurements of this type. In the tests, a narrowband heterodyne CO2 laser radar, operating at a wavelength of 10.6 microns, detected vibration induced differential-Doppler signatures of the LACE satellite. Power spectral densities of forced oscillations and modal frequencies and damping rates of free-damped vibrations were obtained and compared with finite element structural models of the LACE system. Another manifested flight experiment is the Advanced Controls Technology Experiment (ACTEX) designed to demonstrate active and passive damping with piezo-electric (PZT) sensors and actuators. This experiment was developed under the management of the Air Force Phillips Laboratory with integration of the experiment at NRL. It is to ride as a secondary, or 'piggyback,' experiment on a future Navy satellite.

  18. Remote Experiments in Control Engineering Education Laboratory

    Directory of Open Access Journals (Sweden)

    Milica B Naumović

    2008-05-01

    Full Text Available This paper presents Automatic Control Engineering Laboratory (ACEL - WebLab, an under-developed, internet-based remote laboratory for control engineering education at the Faculty of Electronic Engineering in Niš. Up to now, the remote laboratory integrates two physical systems (velocity servo system and magnetic levitation system and enables some levels of measurement and control. To perform experiments in ACEL-WebLab, the "LabVIEW Run Time Engine"and a standard web browser are needed.

  19. Wiki Laboratory Notebooks: Supporting Student Learning in Collaborative Inquiry-Based Laboratory Experiments

    Science.gov (United States)

    Lawrie, Gwendolyn Angela; Grøndahl, Lisbeth; Boman, Simon; Andrews, Trish

    2016-01-01

    Recent examples of high-impact teaching practices in the undergraduate chemistry laboratory that include course-based undergraduate research experiences and inquiry-based experiments require new approaches to assessing individual student learning outcomes. Instructors require tools and strategies that can provide them with insight into individual…

  20. Short-term emissions of ammonia and carbon dioxide from cattle urine contaminated tropical grassland microcosm.

    Science.gov (United States)

    Majumdar, Deepanjan; Patel, Manoj; Drabar, Reena; Vyas, Manish

    2006-11-01

    The study was designed to understand the emissions of ammonia (NH(3)) and carbon dioxide (CO(2)) from a single cattle urination event on a tropical grassland and underline the significance of the emissions in the context of huge animal population grazing on large pasture areas in some countries. Emissions of ammonia (NH(3)) and carbon dioxide (CO(2)) were monitored for three weeks from a tropical grassland (dominated by Cynodon dactylon Pers.) microcosm contaminated with cow and buffalo urine. The grassland microcosms were treated with urine (50 and 100 ml of each) only once and irrigated with water once every week. Ammonia was sampled by an automatic sampling system comprising of a vacuum pump, three-way stopcocks and rubber tubing and an impinger containing suitable absorbing solution (H(2)SO(4)), connected to the tubing suitably. The sampled gas, after sucked by the vacuum pump and absorbed in H(2)SO(4), was allowed to enter the closed microcosm again maintaining internal pressure of the microcosm. Carbon dioxide was sampled by absorption in an alkali (NaOH) trap inside the microcosm. Both NH(3) and CO(2) emissions were highly variable temporally and there was no continuous increasing or decreasing emission trend with time. Respectively, 45 and 46% of total NH(3)-N were emitted within first 48 h from 50 and 100 ml cow urine application while the corresponding values for buffalo urine were 34 and 32%. Total NH(3)-N emissions, integrated for sampling days (i.e. 1, 2, 3, 4, 6, 15, 18 and 21st) were 11 and 6% in cow and 8 and 5% in buffalo urine, of the total-N added through 50 and 100 ml urine samples. Carbon dioxide emissions were standardized at 25 degrees C by using a suitable formula which were lower than actual emissions at actual soil temperature (> 25 degrees C). Carbon dioxide emission rates were classified on the basis of soil repiratory classification and classes ranged from moderately low soil activity up to unusually high soil activity, the latter

  1. Effects of the fungicide metiram in outdoor freshwater microcosms: responses of invertebrates, primany producers and microbes

    OpenAIRE

    Ronghua, Lin; Buijse-Bogdan, L.L.; Rocha Dimitrov, M.; Dohmen, P.; Kosol, Sujitra; Maltby, L.; Roessink, I.; Sinkeldam, J.A.; Smidt, H.; Wijngaarden, van, R.P.A.; Brock, T.C.M.

    2012-01-01

    The ecological impact of the dithiocarbamate fungicide metiram was studied in outdoor freshwater microcosms, consisting of 14 enclosures placed in an experimental ditch. The microcosms were treated three times (interval 7 days) with the formulated product BAS 222 28F (Polyram®). Intended metiram concentrations in the overlying water were 0, 4, 12, 36, 108 and 324 μg a.i./L. Responses of zooplankton, macroinvertebrates, phytoplankton, macrophytes, microbes and community metabolism endpoints we...

  2. Evidence for in situ degradation of mono-and polyaromatic hydrocarbons in alluvial sediments based on microcosm experiments with 13C-labeled contaminants

    International Nuclear Information System (INIS)

    Morasch, B.; Hoehener, P.; Hunkeler, D.

    2007-01-01

    A microcosm study was conducted to investigate the degradation of mono- and polyaromatic hydrocarbons under in situ-like conditions using alluvial sediments from the site of a former cokery. Benzene, naphthalene, or acenaphthene were added to the sediments as 13 C-labeled substrates. Based on the evolution of 13 C-CO 2 determined by gas chromatography isotope-ratio mass spectrometry (GC-IRMS) it was possible to prove mineralization of the compound of interest in the presence of other unknown organic substances of the sediment material. This new approach was suitable to give evidence for the intrinsic biodegradation of benzene, naphthalene, and acenaphthene under oxic and also under anoxic conditions, due to the high sensitivity and reproducibility of 13 C/ 12 C stable isotope analysis. This semi-quantitative method can be used to screen for biodegradation of any slowly degrading, strongly sorbing compound in long-term experiments. - A method based on 13 C-labeled substrates was developed to determine the intrinsic biodegradation potential of aromatic pollutants under oxic and under anoxic conditions

  3. Effects of the fungicide metiram in outdoor freshwater microcosms: responses of invertebrates, primary producers and microbes.

    Science.gov (United States)

    Lin, Ronghua; Buijse, Laura; Dimitrov, Mauricio R; Dohmen, Peter; Kosol, Sujitra; Maltby, Lorraine; Roessink, Ivo; Sinkeldam, Jos A; Smidt, Hauke; Van Wijngaarden, René P A; Brock, Theo C M

    2012-07-01

    The ecological impact of the dithiocarbamate fungicide metiram was studied in outdoor freshwater microcosms, consisting of 14 enclosures placed in an experimental ditch. The microcosms were treated three times (interval 7 days) with the formulated product BAS 222 28F (Polyram®). Intended metiram concentrations in the overlying water were 0, 4, 12, 36, 108 and 324 μg a.i./L. Responses of zooplankton, macroinvertebrates, phytoplankton, macrophytes, microbes and community metabolism endpoints were investigated. Dissipation half-life (DT₅₀) of metiram was approximately 1-6 h in the water column of the microcosm test system and the metabolites formed were not persistent. Multivariate analysis indicated treatment-related effects on the zooplankton (NOEC(community) = 36 μg a.i./L). Consistent treatment-related effects on the phytoplankton and macroinvertebrate communities and on the sediment microbial community could not be demonstrated or were minor. There was no evidence that metiram affected the biomass, abundance or functioning of aquatic hyphomycetes on decomposing alder leaves. The most sensitive populations in the microcosms comprised representatives of Rotifera with a NOEC of 12 μg a.i./L on isolated sampling days and a NOEC of 36 μg a.i./L on consecutive samplings. At the highest treatment-level populations of Copepoda (zooplankton) and the blue-green alga Anabaena (phytoplankton) also showed a short-term decline on consecutive sampling days (NOEC = 108 μg a.i./L). Indirect effects in the form of short-term increases in the abundance of a few macroinvertebrate and several phytoplankton taxa were also observed. The overall community and population level no-observed-effect concentration (NOEC(microcosm)) was 12-36 μg a.i./L. At higher treatment levels, including the test systems that received the highest dose, ecological recovery of affected measurement endpoints was fast (effect period < 8 weeks).

  4. Evaluated fate and effects of atrazine and lambda-cyhalothrin in vegetated and unvegetated microcosms.

    Science.gov (United States)

    Bouldin, J L; Farris, J L; Moore, M T; Smith, S; Stephens, W W; Cooper, C M

    2005-10-01

    Contaminants such as nutrients, metals, and pesticides can interact with constructed wetlands and existing drainage ditches used as agricultural best-management practices. Our research has shown that the presence of macrophytes and a hydrologic regime aid in the transfer and transformation of pesticides associated with agricultural runoff. This study consisted of application of both atrazine (triazine herbicide) and lambda-cyhalothrin (pyrethroid insecticide) to vegetated and unvegetated microcosms in order to measure the fate and effects of pesticides applied at suggested field application rates. Exposures focused on monocultures of Ludwigia peploides (water primrose) and Juncus effusus (soft rush). Pesticide sorption was evident through concentrations of atrazine and lambda-cyhalothrin in plant tissue as high as 2461.4 and 86.50 microg/kg, respectively. Toxicity was measured in water from unvegetated microcosms for 28 days and in Chironomus tentans (midge larvae) exposed to sediment collected from 3 h to 56 days in microcosms receiving the pesticide combination. The comparative survival of test organisms in this study suggests that effective mitigation of pesticides from runoff can depend on the macrophyte contact and vegetative attributes associated with ditches. (c) 2005 Wiley Periodicals, Inc.

  5. The effects of short term exposure to Bass Strait crude oil and Corexit 8667 on benthic community metabolism in Posidonia australis Hook. f. dominated microcosms

    Energy Technology Data Exchange (ETDEWEB)

    Hatcher, A.I.; Larkum, A.W.D.

    1982-03-01

    Microcosms consisting of a sublittoral seagrass meadow from Botany Bay, N.S.W. were maintained in aquaria in a controlled environment room from March to August 1979. Oxygen production and consumption in the microcosms and leaf turnover of the seagrass, Posidonia australis Hook.f. were measured before, during and after a 7-day treatment in June with Bass Strait crude oil and the dispersant Corexit 8667. Four microcosms received oil and two of these received dispersant. The leaf turnover of P. australis was not significantly affected by the addition of oil and dispersant. Photosynthetic oxygen production decreased and respiration increased in the microcosms during treatment. In August, 40 days after treatment, oxygen production rates and P/R ratios in the oil-treated microcosms were higher than rates measured before treatment. The oil-and-dispersant-treated microcosms did not show this trend. The results of this study indicate that a more severe stress is placed on the P. australis dominated benthic community by oil and dispersant than by oil alone.

  6. Tetracyclines and tetracycline resistance in agricultural soils: microcosm and field studies.

    NARCIS (Netherlands)

    Schmitt, Heike; Stoob, Krispin; Hamscher, Gerd; Smit, Eric; Seinen, Willem

    2006-01-01

    The influence of the use of antibiotics on the prevalence of resistance genes in the environment is still poorly understood. We studied the diversity of tetracycline and sulfonamide resistance genes as influenced by fertilization with pig manure in soil microcosms and at two field locations. Manure

  7. A lake as a microcosm: reflections on developments in aquatic ecology

    DEFF Research Database (Denmark)

    Hansson, Lars-Anders; Brodersen, Jakob; Chapman, Ben B.

    2013-01-01

    and still is, specially since it touches upon almost all aspects of the lake ecosystem, from individual behaviour to food web interactions and environmental issues. Therefore, there is no doubt that even if 125 years have passed, Forbes’ paper still is a source of inspiration and deserves to be read. Hence......In the present study, we aim at relating Forbes’ remarkable paper on ‘‘The lake as a microcosm’’, published 125 years ago, to the present status of knowledge in our own research group. Hence, we relate the observations Forbes made to our own microcosm, Lake Krankesjo¨n in southern Sweden, that has...... that lakes are more isolated than many other biomes, but have, indeed, many extensions, for example, input from the catchment, fishing and fish migration. We also conclude that irrespective of whether lakes should be viewed as microcosms or not, the paper by Forbes has been exceptionally influential...

  8. Special Education: A Microcosm of Bureaucracy. Part Two: The Elements of the System

    Science.gov (United States)

    Clark, Ann D.

    1971-01-01

    Delineates a case study of special education that provides a unique microcosm of the emergence of an educational subsystem with inherent and forceful bureaucratic controls that were present from its inception. (Author)

  9. Hydrogen sulfide production by sulfate-reducing bacteria utilizing additives eluted from plastic resins.

    Science.gov (United States)

    Tsuchida, Daisuke; Kajihara, Yusuke; Shimidzu, Nobuhiro; Hamamura, Kengo; Nagase, Makoto

    2011-06-01

    In the present study it was demonstrated that organic additives eluted from plastic resins could be utilized as substrates by sulfate-reducing bacteria. Two laboratory-scale experiments, a microcosm experiment and a leaching experiment, were conducted using polyvinyl chloride (PVC) as a model plastic resin. In the former experiment, the conversion of sulfate to sulfide was evident in microcosms that received plasticized PVC as the sole carbon source, but not in those that received PVC homopolymer. Additionally, dissolved organic carbon accumulated only in microcosms that received plasticized PVC, indicating that the dissolved organic carbon originated from additives. In the leaching experiment, phenol and bisphenol A were found in the leached solutions. These results suggest that the disposal of waste plastics in inert waste landfills may result in the production of H(2)S.

  10. Modelling biological Cr(VI) reduction in aquifer microcosm column systems.

    Science.gov (United States)

    Molokwane, Pulane E; Chirwa, Evans M N

    2013-01-01

    Several chrome processing facilities in South Africa release hexavalent chromium (Cr(VI)) into groundwater resources. Pump-and-treat remediation processes have been implemented at some of the sites but have not been successful in reducing contamination levels. The current study is aimed at developing an environmentally friendly, cost-effective and self-sustained biological method to curb the spread of chromium at the contaminated sites. An indigenous Cr(VI)-reducing mixed culture of bacteria was demonstrated to reduce high levels of Cr(VI) in laboratory samples. The effect of Cr(VI) on the removal rate was evaluated at concentrations up to 400 mg/L. Following the detailed evaluation of fundamental processes for biological Cr(VI) reduction, a predictive model for Cr(VI) breakthrough through aquifer microcosm reactors was developed. The reaction rate in batch followed non-competitive rate kinetics with a Cr(VI) inhibition threshold concentration of approximately 99 mg/L. This study evaluates the application of the kinetic parameters determined in the batch reactors to the continuous flow process. The model developed from advection-reaction rate kinetics in a porous media fitted best the effluent Cr(VI) concentration. The model was also used to elucidate the logistic nature of biomass growth in the reactor systems.

  11. Artificial soil microcosms: a tool for studying microbial autecology under controlled conditions.

    Science.gov (United States)

    Ellis, Richard J

    2004-02-01

    A novel artificial microcosm containing all the essential chemical components of soil, but with reduced heterogeneity and biological complexity, has been developed. Its utility for supporting realistic microbial populations was demonstrated and an example of how competing bacteria can be studied is illustrated.

  12. The Effect of Guided-Inquiry Laboratory Experiments on Science Education Students' Chemistry Laboratory Attitudes, Anxiety and Achievement

    Science.gov (United States)

    Ural, Evrim

    2016-01-01

    The study aims to search the effect of guided inquiry laboratory experiments on students' attitudes towards chemistry laboratory, chemistry laboratory anxiety and their academic achievement in the laboratory. The study has been carried out with 37 third-year, undergraduate science education students, as a part of their Science Education Laboratory…

  13. Abundance and activity of oil-degrading and indigenous bacteria in sediment microcosms

    International Nuclear Information System (INIS)

    Araujo, R.; Molina, M.; Bachoon, D.

    1995-01-01

    The responses of bacterial community composition and degradation crude oil to applications of bioremediation products and plant detrital material were investigated in wetlands microcosms. The microcosms were constructed of sieved sediments and operated as tidal marshes. Products included nutrients, organisms, surfactants and combinations thereof; dried ground Spartina was the source of detrital material. Plate count and most probable-number techniques were used to enumerate microbial populations and GC/MS analysis of indicator petroleum hydrocarbons was used to assess oil degradation. Microbial communities were characterized by whole-genome hybridization and specific probes for bacterial groups, including Pseudomonas, Streptomycetes, Vibrio, and sulfate-reducing bacteria. Although the total microbial numbers were similar in all bioremediation treatments, the numbers of oil degraders increased two to three log units in the fertilizer and microbial-degrader-enriched treatments. Oil-degraders comprised the largest fraction of the total population in the treatment amended with microbial degraders, apparently at the expense of indigenous bacteria, as indicated by specific probes. Oil-degraders were also detected in the subsurface in all treatments except the controls. The extent of oil degradation was not consistent with bacterial numbers; only nutrient additions resulted in significantly enhanced degradation of oil. After 1 month of microcosm operation, oil-degraders had increased at least two orders of magnitude in sediment surface layers when oil was added alone or with Spartina detritus, although total bacterial numbers and the number of oil-degraders decreased to near initial levels by 2 months. The peak coincides with bacterial utilization of the alkane fraction of petroleum hydrocarbons

  14. Bioremediation of 1,2-dichloroethane contaminated groundwater: Microcosm and microbial diversity studies

    International Nuclear Information System (INIS)

    Wang, S.Y.; Kuo, Y.C.; Huang, Y.Z.; Huang, C.W.; Kao, C.M.

    2015-01-01

    In this study, the effectiveness of bioremediating 1,2-dichloroethane (DCA)-contaminated groundwater under different oxidation–reduction processes was evaluated. Microcosms were constructed using indigenous bacteria and activated sludge as the inocula and cane molasses and a slow polycolloid-releasing substrate (SPRS) as the primary substrates. Complete DCA removal was obtained within 30 days under aerobic and reductive dechlorinating conditions. In anaerobic microcosms with sludge and substrate addition, chloroethane, vinyl chloride, and ethene were produced. The microbial communities and DCA-degrading bacteria in microcosms were characterized by 16S rRNA-based denatured-gradient-gel electrophoresis profiling and nucleotide sequence analyses. Real-time polymerase chain reaction was applied to evaluate the variations in Dehalococcoides spp. and Desulfitobacterium spp. Increase in Desulfitobacterium spp. indicates that the growth of Desulfitobacterium might be induced by DCA. Results indicate that DCA could be used as the primary substrate under aerobic conditions. The increased ethene concentrations imply that dihaloelimination was the dominate mechanism for DCA biodegradation. - Highlights: • DCA can be used as the primary substrate and degraded by the indigenous microbial consortia. • Reductive dechlorination of DCA can be enhanced by the supplement of substrates and sludge. • Dihaloelimination is the dominant mechanism for DCA dechlorination and ethene is the end product. • SPRS can serve as the primary substrate and creates anaerobic conditions for DCA dechlorination. • Reductive dechlorination is a feasible option for DCA-contaminated groundwater remediation. - DCA can serve as the primary substrate and degraded by indigenous bacteria aerobically. Dihaloelimination is the dominant mechanism and ethene is the end product via dechlorination

  15. Influence of Coal Ash Leachates and Emergent Macrophytes on Water Quality in Wetland Microcosms

    Data.gov (United States)

    U.S. Environmental Protection Agency — Influence of Coal Ash Leachates and Emergent Macrophytes on Water Quality in Wetland Microcosms. This dataset is associated with the following publication: Olson,...

  16. Mercury decreases culturability of Pseudomonas frederiksbergensis JAJ 28 in soil microcosms

    DEFF Research Database (Denmark)

    Johnsen, Kaare; Ekelund, Flemming; Binnerup, Svend J.

    2003-01-01

    Mercury is a biologically potent heavy metal, which has been found to change the diversity of culturable bacteria. Therefore, we investigated whether Hg kills bacteria in soil or reduces culturability. Soil microcosms were inoculated with Pseudomonas frederiksbergensis JAJ 28 and were sampled...... into account when studying the effects of heavy metals on bacterial diversity....

  17. Identification of degradation routes of metamitron in soil microcosms using 13C-isotope labeling.

    Science.gov (United States)

    Wang, Shizong; Miltner, Anja; Nowak, Karolina M

    2017-01-01

    Metamitron is one of the most commonly used herbicide in sugar beet and flower bulb cultures. Numerous laboratory and field studies on sorption and degradation of metamitron were performed. Detailed biodegradation studies in soil using 13 C-isotope labeling are still missing. Therefore, we aimed at providing a detailed turnover mass balance of 13 C 6 -metamitron in soil microcosms over 80 days. In the biotic system, metamitron mineralized rapidly, and 13 CO 2 finally constituted 60% of the initial 13 C 6 -metamitron equivalents. In abiotic control experiments CO 2 rose to only 7.4% of the initial 13 C 6 -metamitron equivalents. The 13 C label from 13 C 6 -metamitron was incorporated into microbial amino acids that were ultimately stabilized in the soil organic matter forming presumably harmless biogenic residues. Finally, 13 C label from 13 C 6 -metamitron was distributed between the 13 CO 2 and the 13 C-biogenic residues indicating nearly complete biodegradation. The parallel increase of 13 C-alanine, 13 C-glutamate and 13 CO 2 indicates that metamitron was initially biodegraded via the desamino-metamitron route suggesting its relevance in the growth metabolism. In later phases of biodegradation, the "Rhodococcus route" was indicated by the low 13 CO 2 evolution and the high relevance of the pyruvate pathway, which aims at biomolecule synthesis and seems to be related to starvation. This is a first report on the detailed degradation route of metamitron in soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. A Contribution to Real-Time Experiments in Remote Laboratories

    Directory of Open Access Journals (Sweden)

    Zoltán Janík

    2013-02-01

    Full Text Available The paper is focused on realization of hard real-time control of experiments in on-line laboratories. The presented solution utilizes already developed on-line laboratory portal that is based on open-source Scilab environment. The customized solution is based on Linux RTAI platform with RTAI-XML server, Comedi and jRTAILab with support of ScicosLab environment. It generates real-time executable code that is used to operate student experiments performed on Humusoft CE152 Magnetic Levitation plant.

  19. A Virtual Rock Physics Laboratory Through Visualized and Interactive Experiments

    Science.gov (United States)

    Vanorio, T.; Di Bonito, C.; Clark, A. C.

    2014-12-01

    As new scientific challenges demand more comprehensive and multidisciplinary investigations, laboratory experiments are not expected to become simpler and/or faster. Experimental investigation is an indispensable element of scientific inquiry and must play a central role in the way current and future generations of scientist make decisions. To turn the complexity of laboratory work (and that of rocks!) into dexterity, engagement, and expanded learning opportunities, we are building an interactive, virtual laboratory reproducing in form and function the Stanford Rock Physics Laboratory, at Stanford University. The objective is to combine lectures on laboratory techniques and an online repository of visualized experiments consisting of interactive, 3-D renderings of equipment used to measure properties central to the study of rock physics (e.g., how to saturate rocks, how to measure porosity, permeability, and elastic wave velocity). We use a game creation system together with 3-D computer graphics, and a narrative voice to guide the user through the different phases of the experimental protocol. The main advantage gained in employing computer graphics over video footage is that students can virtually open the instrument, single out its components, and assemble it. Most importantly, it helps describe the processes occurring within the rock. These latter cannot be tracked while simply recording the physical experiment, but computer animation can efficiently illustrate what happens inside rock samples (e.g., describing acoustic waves, and/or fluid flow through a porous rock under pressure within an opaque core-holder - Figure 1). The repository of visualized experiments will complement lectures on laboratory techniques and constitute an on-line course offered through the EdX platform at Stanford. This will provide a virtual laboratory for anyone, anywhere to facilitate teaching/learning of introductory laboratory classes in Geophysics and expand the number of courses

  20. The effects of high-tannin leaf litter from transgenic poplars on microbial communities in microcosm soils.

    Directory of Open Access Journals (Sweden)

    Richard S. Winder

    2013-09-01

    Full Text Available The impacts of leaf litter from genetically-modified hybrid poplar accumulating high levels of condensed tannins (proanthocyanidins were examined in soil microcosms consisting of moss growing on sieved soil. Moss preferentially proliferated in microcosms with lower tannin content; DGGE detected increased fungal diversity in microcosms with low-tannin litter. The proportion of cloned rDNA sequences from Actinobacteria decreased with litter addition while Bacteroidetes, Chloroflexi, Cyanobacteria, and α-Proteobacteria significantly increased. β–Proteobacteria were proportionally more numerous at high tannin levels. Tannins had no significant impact on overall diversity of bacterial communities analyzed with various estimators. There was an increased proportion of N-fixing bacteria corresponding to the addition of litter with low tannin levels. The addition of litter increased the proportion of Ascomycota/Basidiomycota. Dothideomycetes, Pucciniomycetes, and Tremellomycetes also increased and Agaricomycetes decreased. Agaricomycetes and Sordariomycetes were significantly more abundant in controls, whereas Pucciniomycetes increased in soil with litter from transformed trees (P = 0.051. Richness estimators and diversity indices revealed no significant difference in the composition of fungal communities; PCoA partitioned the fungal communities into three groups: (i those with higher amounts of added tannin from both transformed and untransformed treatments, (ii those corresponding to soils without litter, and (iii those corresponding to microcosms with litter added from trees transformed only with a β-glucuronidase (GUS control vector. While the litter from transformed poplars had significant effects on soil microbe communities, the observed impacts reflected known impacts on soil processes associated with tannins, and were similar to changes that would be expected from natural variation in tannin levels.

  1. The effects of high-tannin leaf litter from transgenic poplars on microbial communities in microcosm soils.

    Science.gov (United States)

    Winder, Richard S; Lamarche, Josyanne; Constabel, C Peter; Hamelin, Richard C

    2013-01-01

    The impacts of leaf litter from genetically modified hybrid poplar accumulating high levels of condensed tannins (proanthocyanidins) were examined in soil microcosms consisting of moss growing on sieved soil. Moss preferentially proliferated in microcosms with lower tannin content; DGGE (denaturing gradient gel electrophoresis) detected increased fungal diversity in microcosms with low-tannin litter. The proportion of cloned rDNA sequences from Actinobacteria decreased with litter addition while Bacteroidetes, Chloroflexi, Cyanobacteria, and α-Proteobacteria significantly increased. β-Proteobacteria were proportionally more numerous at high-tannin levels. Tannins had no significant impact on overall diversity of bacterial communities analyzed with various estimators. There was an increased proportion of N-fixing bacteria corresponding to the addition of litter with low-tannin levels. The addition of litter increased the proportion of Ascomycota/Basidiomycota. Dothideomycetes, Pucciniomycetes, and Tremellomycetes also increased and Agaricomycetes decreased. Agaricomycetes and Sordariomycetes were significantly more abundant in controls, whereas Pucciniomycetes increased in soil with litter from transformed trees (P = 0.051). Richness estimators and diversity indices revealed no significant difference in the composition of fungal communities; PCoA (principal coordinate analyses) partitioned the fungal communities into three groups: (i) those with higher amounts of added tannin from both transformed and untransformed treatments, (ii) those corresponding to soils without litter, and (iii) those corresponding to microcosms with litter added from trees transformed only with a β-glucuronidase control vector. While the litter from transformed poplars had significant effects on soil microbe communities, the observed impacts reflected known impacts on soil processes associated with tannins, and were similar to changes that would be expected from natural variation in

  2. Effects of nitrate addition on phosphorus retention in an eutrophic reservoir : laboratory experiments

    International Nuclear Information System (INIS)

    Yamada, T.; Janke, H.; Colzato, M.; Beraldo, D.; Mozeto, A.; Botta, C.; Nascimento, M.

    2010-01-01

    The Ibrite reservoir in southeast Brazil is polluted with effluents from an oil refinery as well as domestic untreated sewage from cities in the region. In this study, calcium nitrate was used as a sediment remediation technology in order to reduce phosphorus availability. Experiments were conducted in microcosms incubated for up to 135 days. Ceriodaphnia silvestrii and Vibrio fisheri were used to conduct an acute toxicity assessment of the water column and pore water of the sediments. Chironomus xanthus was used to assess bulk sediments. Results of the chemical analyses showed that high values of acid volatile sulfide in the sediments decreased by 99 per cent after 135 days of incubation. Approximately 50 per cent of the soluble reactive phosphorus was removed from the water column. The toxicity of the tested organisms was attributed to high nitrate concentrations in pore water sediments. Results indicated that calcium nitrate is not suitable as a sediment remediation technology.

  3. Effects of simulated rain on the transport of fonofos and carbofuran from agricultural soils in the three-part environmental microcosm

    International Nuclear Information System (INIS)

    Lichtenstein, E.P.; Liang, T.T.

    1987-01-01

    The effects of simulated rain on the transport and metabolism of [ 14 C]fonofos and [ 14 C]carbofuran from insecticide-treated soil through deeper insecticide-free soil layers into surface waters were studied under laboratory conditions in a three-component microcosm. Radiocarbon derived from both [ 14 C]fonofos and [ 14 C]carbofuran was transported with soil runoff water from the place of the insecticide soil application through previously insecticide-free deeper soil layers into aquaria water and its sediments. Due to the lower water solubility of fonofos, less of this chemical was transported with water than did occur with carbofuran. Water, after its percolation through insecticide-free soil, contained 1.3% and 15.3% of the originally applied fonofos- and carbofuran-derived radiocarbon and 14 C]fonofos-treated soils resulted in lower insect mortalities than did exposure of larvae to comparable water samples from [ 14 C]carbofuran-treated soils. Thirty-six days after the start of the experiments and 21 days after the last rain application, aquaria water plus sediments from [ 14 C]fonofos- or [ 14 C]carbofuran-treated soils contained a total of 1.3% and 6.0% of the originally applied radiocarbon, respectively, but no fonofos and less than 0.1% of the originally applied carbofuran

  4. The effects of H2SO4 and (NH42SO4 treatments on the chemistry of soil drainage water and pine seedlings in forest soil microcosms

    Directory of Open Access Journals (Sweden)

    M. I. Stutter

    2004-01-01

    Full Text Available An experiment comparing effects of sulphuric acid and reduced N deposition on soil water quality and on chemical and physical growth indicators for forest ecosystems is described. Six H2SO4 and (NH42SO4 treatment loads, from 0 – 44 and 0 – 25 kmolc ha-1 yr-1, respectively, were applied to outdoor microcosms of Pinus sylvestris seedlings in 3 acid to intermediate upland soils (calc-silicate, quartzite and granite for 2 years. Different soil types responded similarly to H2SO4 loads, resulting in decreased leachate pH, but differently to reduced N inputs. In microcosms of calc-silicate soil, nitrification of NH4 resulted in lower pH and higher cation leaching than in acid treatments. By contrast, in quartzite and granite soils, (NH42SO4 promoted direct cation leaching, although leachate pH increased. The results highlighted the importance of soil composition on the nature of the cations leached, the SO4 adsorption capacities and microbial N transformations. Greater seedling growth on calc-silicate soils under both treatment types was related to sustained nutrient availability. Reductions in foliar P and Mg with higher N treatments were observed for seedlings in the calc-silicate soil. There were few treatment effects on quartzite and granite microcosm tree seedlings since P limitation precluded seedling growth responses to treatments. Hence, any benefits of N deposition to seedlings on quartzite and granite soils appeared limited by availability of co-nutrients, exacerbated by rapid depletion of soil exchangeable base cations. Keywords: acidification, manipulation, nitrogen, ammonium, deposition, soil, drainage, pine, microcosms, forest

  5. Microbial degradation of street dust polycyclic aromatic hydrocarbons in microcosms simulating diffuse pollution of urban soil

    DEFF Research Database (Denmark)

    Johnsen, Anders R; de Lipthay, Julia R; Sørensen, Søren J

    2006-01-01

    Diffuse pollution with polycyclic aromatic hydrocarbons (PAHs) of topsoil in urban regions has caused increasing concerns in recent years. We simulated diffuse pollution of soil in microcosms by spiking sandy topsoil (A-horizon) and coarse, mineral subsoil (C-horizon) with street dust (PM63...... for the persistence and low bioaccessibility of 5- and 6-ring PAHs in diffusely polluted soil.......) isolated from municipal street sweepings from central Copenhagen. The microbial communities adapted to PAH degradation in microcosms spiked with street dust in both A-horizon and C-horizon soils, in spite of low PAH-concentrations. The increased potential for PAH degradation was demonstrated on several...

  6. Development of sensorial experiments and their implementation into undergraduate laboratories

    Science.gov (United States)

    Bromfield Lee, Deborah Christina

    "Visualization" of chemical phenomena often has been limited in the teaching laboratories to the sense of sight. We have developed chemistry experiments that rely on senses other than eyesight to investigate chemical concepts, make quantitative determinations, and familiarize students with chemical techniques traditionally designed using only eyesight. Multi-sensory learning can benefit all students by actively engaging them in learning through stimulation or an alternative way of experiencing a concept or ideas. Perception of events or concepts usually depends on the information from the different sensory systems combined. The use of multi-sensory learning can take advantage of all the senses to reinforce learning as each sense builds toward a more complete experience of scientific data. Research has shown that multi-sensory representations of scientific phenomena is a valuable tool for enhancing understanding of chemistry as well as displacing misconceptions through experience. Multi-sensory experiences have also been shown to enrich memory performance. There are few experiments published which utilize multiple senses in the teaching laboratory. The sensorial experiments chosen were conceptually similar to experiments currently performed in undergraduate laboratories; however students collect different types of data using multi-sensory observations. The experiments themselves were developed by using chemicals that would provide different sensory changes or capitalizing on sensory observations that were typically overlooked or ignored and obtain similar and precise results as in traditional experiments. Minimizing hazards and using safe practices are especially essential in these experiments as students utilize senses traditionally not allowed to be used in the laboratories. These sensorial experiments utilize typical equipment found in the teaching laboratories as well as inexpensive chemicals in order to aid implementation. All experiments are rigorously tested

  7. A combined microcosm and mesocosm approach to examine factors affecting survival and mortality of Pseudomonas fluorescens Ag1 in seawater

    DEFF Research Database (Denmark)

    Ahl, Thomas; Christoffersen, K.; Riemann, B.

    1995-01-01

    .5‰). In microcosms with 0.2 µm-filtered seawater, addition of a carbon + nitrogen + phosphorus nutrient mixture was needed to induce proliferation of Ag1. In nutrient-amended microcosms the Ag1 population maintained viability, as determined by the direct viable counts method, at a level close to 100%. In natural...

  8. Physiological aspects of mangrove (Laguncularia racemosa) grown in microcosms with oil-degrading bacteria and oil contaminated sediment

    International Nuclear Information System (INIS)

    Sodré, Vanessa; Caetano, Vanessa S.; Rocha, Renata M.; Carmo, Flávia L.; Medici, Leonardo O.; Peixoto, Raquel S.; Rosado, Alexandre S.

    2013-01-01

    To assess the severity of oil spills on mangroves, diagnosis of the vegetation health is crucial. Some aspects of photosynthesis such as photochemical efficiency and leaf pigment composition together with the level of oxidative stress may constitute reliable indicators for vegetation health. To test this approach 14 month old Laguncularia racemosa were contaminated with 5 L m −2 of the marine fuel oil MF-380 and treated with an oil degrading bacterial consortium in microcosms. Contamination resulted in a 20% decrease in shoot dry weight after 128 days. Photochemical efficiency, pigment content, catalase and ascorbate peroxidase remained unchanged. Multivariate ordination of DGGE microbial community fingerprints revealed a pronounced separation between the oil contaminated and the non-contaminated samples. Further studies are necessary before physiological parameters can be recommended as indicators for plant's health in oil polluted mangroves. - Highlights: ► L. racemosa growth rate was reduced by 20% in response to a simulated oil spill of 5 L m −2 in a microcosm. ► Photochemistry was not directly affected by the oil contamination during the 128-day experiment. ► Oil contamination changed the rhizobacterial community. ► The oil degrading bacteria consortium did not affect plant growth. - Despite the need to establish methods to diagnose the health status of mangroves little is known about the impacts of petrochemicals on mangrove plants and associated rhizosphere microorganisms.

  9. Fluorescence quantum yield measurements of fluorescent proteins: a laboratory experiment for a biochemistry or molecular biophysics laboratory course.

    Science.gov (United States)

    Wall, Kathryn P; Dillon, Rebecca; Knowles, Michelle K

    2015-01-01

    Fluorescent proteins are commonly used in cell biology to assess where proteins are within a cell as a function of time and provide insight into intracellular protein function. However, the usefulness of a fluorescent protein depends directly on the quantum yield. The quantum yield relates the efficiency at which a fluorescent molecule converts absorbed photons into emitted photons and it is necessary to know for assessing what fluorescent protein is the most appropriate for a particular application. In this work, we have designed an upper-level, biochemistry laboratory experiment where students measure the fluorescence quantum yields of fluorescent proteins relative to a standard organic dye. Four fluorescent protein variants, enhanced cyan fluorescent protein (ECFP), enhanced green fluorescent protein (EGFP), mCitrine, and mCherry, were used, however the methods described are useful for the characterization of any fluorescent protein or could be expanded to fluorescent quantum yield measurements of organic dye molecules. The laboratory is designed as a guided inquiry project and takes two, 4 hr laboratory periods. During the first day students design the experiment by selecting the excitation wavelength, choosing the standard, and determining the concentration needed for the quantum yield experiment that takes place in the second laboratory period. Overall, this laboratory provides students with a guided inquiry learning experience and introduces concepts of fluorescence biophysics into a biochemistry laboratory curriculum. © 2014 The International Union of Biochemistry and Molecular Biology.

  10. Effects of lambda-cyhalothrin in two ditch microcosm systems of different trophic status

    NARCIS (Netherlands)

    Roessink, I.; Arts, G.H.P.; Belgers, J.D.M.; Bransen, F.F.J.; Maund, S.J.; Brock, T.C.M.

    2005-01-01

    The fate and effects of the pyrethroid insecticide lambda-cyhalothrin were compared in mesotrophic (macrophyte-dominated) and eutrophic (phytoplankton-dominated) ditch microcosms (0.5 m3). Lambda-cyhalothrin was applied three times at one-week intervals at concentrations of 10, 25, 50, 100, and 250

  11. Argumentation in the Chemistry Laboratory: Inquiry and Confirmatory Experiments

    Science.gov (United States)

    Katchevich, Dvora; Hofstein, Avi; Mamlok-Naaman, Rachel

    2013-02-01

    One of the goals of science education is to provide students with the ability to construct arguments—reasoning and thinking critically in a scientific context. Over the years, many studies have been conducted on constructing arguments in science teaching, but only few of them have dealt with studying argumentation in the laboratory. Our research focuses on the process in which students construct arguments in the chemistry laboratory while conducting various types of experiments. It was found that inquiry experiments have the potential to serve as an effective platform for formulating arguments, owing to the features of this learning environment. The discourse during inquiry-type experiments was found to be rich in arguments, whereas that during confirmatory-type experiments was found to be sparse in arguments. The arguments, which were developed during the discourse of an open inquiry experiment, focus on the hypothesis-building stage, analysis of the results, and drawing appropriate conclusions.

  12. Diffusion Experiments in Opalinus Clay: Laboratory, Large-Scale Diffusion Experiments and Microscale Analysis by RBS.

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Gutierrez, M.; Alonso de los Rios, U.; Missana, T.; Cormenzana, J.L.; Mingarro, M.; Morejon, J.; Gil, P.

    2008-08-06

    The Opalinus Clay (OPA) formation in the Zurcher Weiland (Switzerland) is a potential host rock for a repository for high-level radioactive waste. Samples collected in the Mont Terri Underground Rock Laboratory (URL), where the OPA formation is located at a depth between -200 and -300 m below the surface, were used to study the radionuclide diffusion in clay materials. Classical laboratory essays and a novel experimental set-up for large-scale diffusion experiments were performed together to a novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS), to understand the transport properties of the OPA and to enhance the methodologies used for in situ diffusion experiments. Through-Diffusion and In-Diffusion conventional laboratory diffusion experiments were carried out with HTO, 36{sup C}l-, I-, 22{sup N}a, 75{sup S}e, 85{sup S}r, 233{sup U}, 137{sup C}s, 60{sup C}o and 152{sup E}u. Large-scale diffusion experiments were performed with HTO, 36{sup C}l, and 85{sup S}r, and new experiments with 60{sup C}o, 137{sup C}s and 152{sup E}u are ongoing. Diffusion experiments with RBS technique were done with Sr, Re, U and Eu. (Author) 38 refs.

  13. A Laboratory Experiment on EM Backscatter from Farley-Buneman and Gradient Drift Waves

    DEFF Research Database (Denmark)

    Alport, M. J.; D'Angelo, N.; Pécseli, Hans

    1981-01-01

    Results are reported of a laboratory experiment on Bragg backscatter of 3-cm microwaves by turbulent waves driven by the Farley-Buneman and gradient drift instabilities. The present work is the third in a series of laboratory experiments performed to test, under controlled conditions, prevalent i...... ideas on EM scattering by equatorial and high-latitude ionospheric waves and irregularities.......Results are reported of a laboratory experiment on Bragg backscatter of 3-cm microwaves by turbulent waves driven by the Farley-Buneman and gradient drift instabilities. The present work is the third in a series of laboratory experiments performed to test, under controlled conditions, prevalent...

  14. Modelling of laboratory high-pressure infiltration experiments

    International Nuclear Information System (INIS)

    Smith, P.A.

    1992-02-01

    This report describes the modelling of break-through curves from a series of two-tracer dynamic infiltration experiments, which are intended to complement larger scale experiments at the Nagra Grimsel Test Site. The tracers are 82 Br, which is expected to be non-sorbing, and 24 Na, which is weakly sorbing. The 24 Na concentration is well below the natural Na concentration in the infiltration fluid, so that sorption on the rock is governed by isotopic exchange, exhibiting a linear isotherm. The rock specimens are sub-samples (cores) of granodiorite from the Grimsel Test Site, each containing a distinct shear zone. Best-fits to the break-through curves using single-porosity and dual-porosity transport models are compared and several physical parameters are extracted. It is shown that the dual-porosity model is required in order to reproduce the tailing part of the break-through curves for the non-sorbing tracer. The single-porosity model is sufficient to reproduce the break-through curves for the sorbing tracer within the estimated experimental errors. Extracted K d values are shown to agree well with a field rock-water interaction experiment and in situ migration experiments. Static, laboratory batch-sorption experiments give a larger K d , but this difference could be explained by the larger surface area available for sorption in the artificially crushed samples used in the laboratory and by a slightly different water chemistry. (author) 13 figs., tabs., 19 refs

  15. Freeze Drying of Fruits and Vegetables: A Laboratory Experiment.

    Science.gov (United States)

    Noble, Richard D.

    1979-01-01

    Describes a laboratory experiment for freeze-drying fruits and vegetables which aims to expose college students to the principles of drying and simultaneous heat and mass transfer. The experimental apparatus, procedure of the experiment, and data analysis are also included. (HM)

  16. Critical experiments at Sandia National Laboratories

    International Nuclear Information System (INIS)

    Harms, Gary A.; Ford, John T.; Barber, Allison Delo

    2010-01-01

    Sandia National Laboratories (SNL) has conducted radiation effects testing for the Department of Energy (DOE) and other contractors supporting the DOE since the 1960's. Over this period, the research reactor facilities at Sandia have had a primary mission to provide appropriate nuclear radiation environments for radiation testing and qualification of electronic components and other devices. The current generation of reactors includes the Annular Core Research Reactor (ACRR), a water-moderated pool-type reactor, fueled by elements constructed from UO2-BeO ceramic fuel pellets, and the Sandia Pulse Reactor III (SPR-III), a bare metal fast burst reactor utilizing a uranium-molybdenum alloy fuel. The SPR-III is currently defueled. The SPR Facility (SPRF) has hosted a series of critical experiments. A purpose-built critical experiment was first operated at the SPRF in the late 1980's. This experiment, called the Space Nuclear Thermal Propulsion Critical Experiment (CX), was designed to explore the reactor physics of a nuclear thermal rocket motor. This experiment was fueled with highly-enriched uranium carbide fuel in annular water-moderated fuel elements. The experiment program was completed and the fuel for the experiment was moved off-site. A second critical experiment, the Burnup Credit Critical Experiment (BUCCX) was operated at Sandia in 2002. The critical assembly for this experiment was based on the assembly used in the CX modified to accommodate low-enriched pin-type fuel in water moderator. This experiment was designed as a platform in which the reactivity effects of specific fission product poisons could be measured. Experiments were carried out on rhodium, an important fission product poison. The fuel and assembly hardware for the BUCCX remains at Sandia and is available for future experimentation. The critical experiment currently in operation at the SPRF is the Seven Percent Critical Experiment (7uPCX). This experiment is designed to provide benchmark

  17. Dental plaque microcosm biofilm behavior on calcium phosphate nanocomposite with quaternary ammonium.

    Science.gov (United States)

    Cheng, Lei; Weir, Michael D; Zhang, Ke; Wu, Eric J; Xu, Sarah M; Zhou, Xuedong; Xu, Hockin H K

    2012-08-01

    Half of dental restorations fail in 10 years, with secondary caries as the main reason. Calcium phosphate composites could remineralize tooth lesions. The objectives of this study were to: (1) impart antibacterial activity to a composite with nanoparticles of amorphous calcium phosphate (NACP); and (2) investigate the effect of quaternary ammonium dimethacrylate (QADM) on mechanical and dental plaque microcosm biofilm properties for the first time. The NACP and glass particles were filled into a dental resin that contained bis(2-methacryloyloxy-ethyl) dimethyl-ammonium bromide, the QADM. NACP nanocomposites containing 0%, 7%, 14%, and 17.5% of QADM by mass, respectively, were photo-cured. A commercial composite with no antibacterial activity was used as control. Mechanical properties were measured in three-point flexure. A human saliva microcosm model was used to grow biofilms on composites. Live/dead assay, metabolic activity, colony-forming unit (CFU) counts, and lactic acid production of biofilms on the composites were measured. Increasing QADM mass fraction monotonically reduced the biofilm viability, CFU and lactic acid. Biofilms on NACP nanocomposite with 17.5% QADM had metabolic activity that was 30% that on a commercial composite control (pbacterial cells with normal short-rod shapes, while some cells on NACP-QADM nanocomposites disintegrated into pieces. Adding QADM to NACP did not decrease the composite strength and elastic modulus, which matched (p>0.1) those of a commercial composite without Ca-PO(4) or antibacterial activity. A dental plaque microcosm model was used to evaluate the novel NACP-QADM nanocomposite. The nanocomposite greatly reduced the biofilm viability, metabolic activity and lactic acid, while its mechanical properties matched those of a commercial composite. NACP-QADM nanocomposite with calcium phosphate fillers, good mechanical properties and a strong antibacterial activity may have potential for anti-biofilm and anti

  18. Interactive screen experiments-innovative virtual laboratories for distance learners

    International Nuclear Information System (INIS)

    Hatherly, P A; Jordan, S E; Cayless, A

    2009-01-01

    The desirability and value of laboratory work for physics students is a well-established principle and issues arise where students are inherently remote from their host institution, as is the case for the UK's Open University. In this paper, we present developments from the Physics Innovations Centre for Excellence in Teaching and Learning (piCETL) in the production and technology of the virtual laboratory resources, interactive screen experiments, and the benefits and drawbacks of such resources. We also explore the motivations behind current implementation of interactive screen experiments and examine evaluation strategies and outcomes through a series of case studies

  19. High Performance Liquid Chromatography Experiments to Undergraduate Laboratories

    Science.gov (United States)

    Kissinger, Peter T.; And Others

    1977-01-01

    Reviews the principles of liquid chromatography with electrochemical detection (LCEC), an analytical technique that incorporates the advantages of both liquids chromatography and electrochemistry. Also suggests laboratory experiments using this technique. (MLH)

  20. The Qweakp experiment at Jefferson Laboratory

    International Nuclear Information System (INIS)

    Page, Shelley

    2008-01-01

    A major new experiment is being prepared at Jefferson Laboratory to measure the proton's weak charge via the parity violating asymmetry in elastic electron-proton scattering at very low momentum transfer. The Standard Model makes a firm prediction of the proton' weak charge, Q w p = 1 - 4 sin2thetaW, based on the running of the weak mixing angle sin2thetaW from the Z 0 pole down to low energies, corresponding to a 10sigma effect in our experiment. Our ultimate goal is to determine the proton' weak charge with 4% combined statistical and systematic errors, which in turn leads to a 0.3% measurement of sin2 thetaW. The experiment is currently under construction; installation in Hall C at Jefferson Lab followed by data taking is planned for 2009.

  1. Laser fusion experiments at the Lawrence Livermore Laboratory

    International Nuclear Information System (INIS)

    Ahlstrom, H.G.

    1975-01-01

    A short review is given of some of the important dates in the experimental fusion program at Livermore. A few of the parameters of the laser systems which are being used for these experiments are mentioned. Some information about specialized diagnostics which have been developed at the Livermore Laboratory for these experiments is described. The focusing arrangements for each of the systems are discussed. Experiments both on planar targets and on targets for laser fusion are described

  2. Laboratory Experiments in Teaching Public Economics and Policy

    Directory of Open Access Journals (Sweden)

    Špačková Zuzana

    2015-05-01

    Full Text Available This paper deals with classroom experiments in economics, which have been derived from laboratory experiments. These experiments cover a broad range of topics, from strictly economic ones (like market games or auctions to those with overlaps to other domains such as public policy. The paper discusses different methodologies of research and classroom experiments, introduces the benefits of the latter and presents a concrete teaching experiment used in public economics courses at the Faculty of Economics and Administration of Masaryk University. Another link between economic experiments and public policy is outlined here as well, namely the importance of experimental results for public policy makers.

  3. Agreed Discoveries: Students' Negotiations in a Virtual Laboratory Experiment

    Science.gov (United States)

    Karlsson, Goran; Ivarsson, Jonas; Lindstrom, Berner

    2013-01-01

    This paper presents an analysis of the scientific reasoning of a dyad of secondary school students about the phenomenon of dissolution of gases in water as they work on this in a simulated laboratory experiment. A web-based virtual laboratory was developed to provide learners with the opportunity to examine the influence of physical factors on gas…

  4. Effects of substrate type and arsenic dosage level on arsenic behavior in grassland microcosms. Part I. Preliminary results on 74As transport

    International Nuclear Information System (INIS)

    Draggan, S.

    1977-01-01

    Microcosm design is an important factor in interpreting results obtained from studies of the environmental effects, mobility and persistence of contaminants. The behavior of pentavalent arsenic and a radioarsenic tracer was studied in three substrate types exposed to differing levels of stable As dosage. Soil cores excised intact from a natural grassland ecosystem were considered to most reliably represent the natural system under study since they retained the soil structure, and closely simulated the abiotic and biotic complexity, of the grassland ecosystem. The behavior of 74 As in the components of intact soil core microcosms differed appreciably from that observed for the other microcosm types where soil underwent manipulation. These differences were explained primarily on the basis of differences in soil structure

  5. Detection by denaturing gradient gel electrophoresis of ammonia-oxidizing bacteria in microcosms of crude oil-contaminated mangrove sediments.

    Science.gov (United States)

    dos Santos, A C F; Marques, E L S; Gross, E; Souza, S S; Dias, J C T; Brendel, M; Rezende, R P

    2012-01-27

    Currently, the effect of crude oil on ammonia-oxidizing bacterium communities from mangrove sediments is little understood. We studied the diversity of ammonia-oxidizing bacteria in mangrove microcosm experiments using mangrove sediments contaminated with 0.1, 0.5, 1, 2, and 5% crude oil as well as non-contaminated control and landfarm soil from near an oil refinery in Camamu Bay in Bahia, Brazil. The evolution of CO(2) production in all crude oil-contaminated microcosms showed potential for mineralization. Cluster analysis of denaturing gradient gel electrophoresis-derived samples generated with primers for gene amoA, which encodes the functional enzyme ammonia monooxygenase, showed differences in the sample contaminated with 5% compared to the other samples. Principal component analysis showed divergence of the non-contaminated samples from the 5% crude oil-contaminated sediment. A Venn diagram generated from the banding pattern of PCR-denaturing gradient gel electrophoresis was used to look for operational taxonomic units (OTUs) in common. Eight OTUs were found in non-contaminated sediments and in samples contaminated with 0.5, 1, or 2% crude oil. A Jaccard similarity index of 50% was found for samples contaminated with 0.1, 0.5, 1, and 2% crude oil. This is the first study that focuses on the impact of crude oil on the ammonia-oxidizing bacterium community in mangrove sediments from Camamu Bay.

  6. Comparison of Rooting Strategies to Explore Rock Fractures for Shallow Soil-Adapted Tree Species with Contrasting Aboveground Growth Rates: A Greenhouse Microcosm Experiment.

    Science.gov (United States)

    Nie, Yunpeng; Chen, Hongsong; Ding, Yali; Yang, Jing; Wang, Kelin

    2017-01-01

    For tree species adapted to shallow soil environments, rooting strategies that efficiently explore rock fractures are important because soil water depletion occurs frequently. However, two questions: (a) to what extent shallow soil-adapted species rely on exploring rock fractures and (b) what outcomes result from drought stress, have rarely been tested. Therefore, based on the expectation that early development of roots into deep soil layers is at the cost of aboveground growth, seedlings of three tree species ( Cyclobalanopsis glauca, Delavaya toxocarpa , and Acer cinnamomifolium ) with distinct aboveground growth rates were selected from a typical shallow soil region. In a greenhouse experiment that mimics the basic features of shallow soil environments, 1-year-old seedlings were transplanted into simulated microcosms of shallow soil overlaying fractured bedrock. Root biomass allocation and leaf physiological activities, as well as leaf δ 13 C values were investigated and compared for two treatments: regular irrigation and repeated cycles of drought stress. Our results show that the three species differed in their rooting strategies in the context of encountering rock fractures, however, these strategies were not closely related to the aboveground growth rate. For the slowest-growing seedling, C. glauca , percentages of root mass in the fractures, as well as in the soil layer between soil and bedrock increased significantly under both treatments, indicating a specialized rooting strategy that facilitated the exploration of rock fractures. Early investment in deep root growth was likely critical to the establishment of this drought-vulnerable species. For the intermediate-growing, A. cinnamomifolium , percentages of root mass in the bedrock and interface soil layers were relatively low and exhibited no obvious change under either treatment. This limited need to explore rock fractures was compensated by a conservative water use strategy. For the fast-growing, D

  7. Comparison of Rooting Strategies to Explore Rock Fractures for Shallow Soil-Adapted Tree Species with Contrasting Aboveground Growth Rates: A Greenhouse Microcosm Experiment

    Directory of Open Access Journals (Sweden)

    Yunpeng Nie

    2017-09-01

    Full Text Available For tree species adapted to shallow soil environments, rooting strategies that efficiently explore rock fractures are important because soil water depletion occurs frequently. However, two questions: (a to what extent shallow soil-adapted species rely on exploring rock fractures and (b what outcomes result from drought stress, have rarely been tested. Therefore, based on the expectation that early development of roots into deep soil layers is at the cost of aboveground growth, seedlings of three tree species (Cyclobalanopsis glauca, Delavaya toxocarpa, and Acer cinnamomifolium with distinct aboveground growth rates were selected from a typical shallow soil region. In a greenhouse experiment that mimics the basic features of shallow soil environments, 1-year-old seedlings were transplanted into simulated microcosms of shallow soil overlaying fractured bedrock. Root biomass allocation and leaf physiological activities, as well as leaf δ13C values were investigated and compared for two treatments: regular irrigation and repeated cycles of drought stress. Our results show that the three species differed in their rooting strategies in the context of encountering rock fractures, however, these strategies were not closely related to the aboveground growth rate. For the slowest-growing seedling, C. glauca, percentages of root mass in the fractures, as well as in the soil layer between soil and bedrock increased significantly under both treatments, indicating a specialized rooting strategy that facilitated the exploration of rock fractures. Early investment in deep root growth was likely critical to the establishment of this drought-vulnerable species. For the intermediate-growing, A. cinnamomifolium, percentages of root mass in the bedrock and interface soil layers were relatively low and exhibited no obvious change under either treatment. This limited need to explore rock fractures was compensated by a conservative water use strategy. For the fast

  8. Fate and effects of the insecticide chlorpyrifos in outdoor plankton-dominated microcosms in Thailand.

    NARCIS (Netherlands)

    Daam, M.A.; Crum, S.J.H.; Brink, van den P.J.; Nogueira, A.J.A.

    2008-01-01

    The fate and effects of the insecticide chlorpyrifos were studied in plankton-dominated, freshwater microcosms in Thailand. Disappearance rates of chlorpyrifos from the water column in the present study were similar to those in temperate regions. Insecticide accumulation in the sediment was

  9. A Laboratory Experiment for Rapid Determination of the Stability of Vitamin C

    Science.gov (United States)

    Adem, Seid M.; Lueng, Sam H.; Elles, Lisa M. Sharpe; Shaver, Lee Alan

    2016-01-01

    Experiments in laboratory manuals intended for general, organic, and biological (GOB) chemistry laboratories include few opportunities for students to engage in instrumental methods of analysis. Many of these students seek careers in modern health-related fields where experience in spectroscopic techniques would be beneficial. A simple, rapid,…

  10. Increases of Chamber Height and Base Diameter Have Contrasting Effects on Grazing Rate of Two Cladoceran Species: Implications for Microcosm Studies

    Science.gov (United States)

    Pan, Ying; Zhang, Yunshu; Peng, Yan; Zhao, Qinghua; Sun, Shucun

    2015-01-01

    Aquatic microcosm studies often increase either chamber height or base diameter (to increase water volume) to test spatial ecology theories such as “scale” effects on ecological processes, but it is unclear whether the increase of chamber height or base diameter have the same effect on the processes, i.e., whether the effect of the shape of three-dimensional spaces is significant. We orthogonally manipulated chamber height and base diameter and determined swimming activity, average swimming velocity and grazing rates of the cladocerans Daphnia magna and Moina micrura (on two algae Scenedesmus quadricauda and Chlorella vulgaris; leading to four aquatic algae-cladoceran systems in total) under different microcosm conditions. Across all the four aquatic systems, increasing chamber height at a given base diameter significantly decreased the duration and velocity of horizontal swimming, and it tended to increase the duration but decrease the velocity of vertical swimming. These collectively led to decreases in both average swimming velocity and grazing rate of the cladocerans in the tall chambers (at a given base diameter), in accordance with the positive relationship between average swimming velocity and grazing rate. In contrast, an increase of base diameter at a given chamber height showed contrasting effects on the above parameters. Consistently, at a given chamber volume increasing ratio of chamber height to base diameter decreased the average swimming velocity and grazing rate across all the aquatic systems. In general, increasing chamber depth and base diameter may exert contrasting effects on zooplankton behavior and thus phytoplankton-zooplankton interactions. We suggest that spatial shape plays an important role in determining ecological process and thus should be considered in a theoretical framework of spatial ecology and also the physical setting of aquatic microcosm experiments. PMID:26273836

  11. Science museum staff taking part in the ECSITE 2018 conference visit Microcosm

    CERN Multimedia

    AUTHOR|(CDS)2070299; Ordan, Julien Marius

    2018-01-01

    Science museum staff taking part in the ECSITE 2018 conference visit Microcosm with Marta Bajko and Dwayne Spiteri guiding. https://cern.service-now.com/nav_to.do?uri=u_request_fulfillment.do%3Fsys_id=ae774fec4fa653401bb8c0501310c748%26sysparm_stack=u_request_fulfillment_list.do%3Fsysparm_query=active=true

  12. Solvent-Free Wittig Reaction: A Green Organic Chemistry Laboratory Experiment

    Science.gov (United States)

    Leung, Sam H.; Angel, Stephen A.

    2004-01-01

    Some Wittig reactions can be carried out by grinding the reactants in a mortar with a pestle for about 20 minutes, as per investigation. A laboratory experiment involving a solvent-free Wittig reaction that can be completed in a three-hour sophomore organic chemistry laboratory class period, are developed.

  13. Influence of linear alkylbenzene sulfonate (LAS) on the structure of Alphaproteobacteria, Actinobacteria, and Acidobacteria communities in a soil microcosm.

    Science.gov (United States)

    Sánchez-Peinado, M del Mar; González-López, Jesús; Martínez-Toledo, M Victoria; Pozo, Clementina; Rodelas, Belén

    2010-03-01

    lower in the microcosms receiving 50 mg l(-1) LAS and in the lower portion of soil cores. The clear differentiation of the samples of the upper portion of the soil columns amended with LAS was specifically related to the presence and intensity of a distinctive major band (named band class 7). There was a statistically significant positive correlation between the concentrations of LAS detected in soil portions taken from LAS 10 mg l(-1) and LAS 50 mg l(-1) microcosms and the relative intensity of band class 7 in the corresponding TGGE profiles. Prevalent Alphaproteobacteria populations in the soil microcosms had close similarity (>99%) to cultivated species affiliated to genera of the Rhizobiaceae, Methylocystaceae, Hyphomicrobiaceae, Rhodospirillaceae, Brucellaceae, Bradyrhizobiaceae, and Caulobacteraceae families. The population represented by band class 7 was found closely related to the genus Phenylobacterium (Caulobacteraceae). According to cluster analysis of TGGE profiles, the structure of both Actinobacteria and Acidobacteria communities in the soil microcosms was remarkably stable in the presence of LAS at the two concentrations tested, as most bands were universally present in all samples and displayed fairly similar relative intensities. Previous studies by others authors, based on biological and chemical tests, concluded that LAS toxicity was not an important microbial selection factor in sludge amended soil, while work based on the use of molecular fingerprinting to evaluate the impact of LAS in aqueous media and marine sediments showed that concentrations as low as 1 mg l(-1) significantly influence the development of the bacterial community structure. Although TGGE is not a strictly quantitative method due to the bias introduced by the PCR reaction, changes of band intensity through experiments are a consequence of a change in the relative abundance of the corresponding populations in the community and can be used as a semiquantitative measure of bacterial

  14. Experience of maintaining laboratory educational website's sustainability.

    Science.gov (United States)

    Dimenstein, Izak B

    2016-01-01

    Laboratory methodology websites are specialized niche websites. The visibility of a niche website transforms it into an authority site on a particular "niche of knowledge." This article presents some ways in which a laboratory methodology website can maintain its sustainability. The optimal composition of the website includes a basic content, a blog, and an ancillary part. This article discusses experimenting with the search engine optimization query results page. Strategic placement of keywords and even phrases, as well as fragmentation of the post's material, can improve the website's visibility to search engines. Hyperlinks open a chain reaction of additional links and draw attention to the previous posts. Publications in printed periodicals are a substantial part of a niche website presence on the Internet. Although this article explores a laboratory website on the basis of our hands-on expertise maintaining "Grossing Technology in Surgical Pathology" (www.grossing-technology.com) website with a high volume of traffic for more than a decade, the recommendations presented here for developing an authority website can be applied to other professional specialized websites. The authority websites visibility and sustainability are preconditions for aggregating them in a specialized educational laboratory portal.

  15. Evaluation of anaerobic in-situ bioremediation of chlorinated hydrocarbons and BTEX with laboratory microcosm and PCR

    Energy Technology Data Exchange (ETDEWEB)

    Gemoets, J.; Lookman, R.; Borremans, B.; Ceuster, T. de [VITO, Mol (Belgium)

    2003-07-01

    The results of a number of microcosm studies are presented for contaminated aquifer materials which were collected from a variety of industrial sites. These represent the following contaminant situations: perchloro-ethylene, trichloro-ethylene and their degradation products, 1,1,1-TCA and DCA and a site with a complex mixture of trichloro-ethene, cDCE, dichloro-methane, 1,1,1-TCA, 1,1-DCA, 1,2-dichloropropane, toluene, xylenes, 1,24-trimethylbenzene and mineral oil. The following electron donors were evaluated for their ability to stimulate halorespiration: lactate, methanol, ethanol, molasses and yeast extract. All of these carbon sources were found to stimulate biodegradation of chlorinated ethenes, but their relative performance was found to be site specific. For a number of sites, stagnation was observed at cDCE, for other sites complete conversion of PER and TRI to ethene was observed. Some aquifer materials were screened for the presence of genetic material of Dehalococcoides sp. by means of the polymerase chain reaction. Dehalococcoides sp. are believed to be required for complete reduction of perchloro-ethylene or trichloro-ethylene to ethene. A positive signal was found for aquifer material which exhibited formation of ethene, while soil material from another area at the same site which did not exhibit formation of ethene gave a negative PCR-signal. For two sites anaerobic biodegradation of 1,1,1-TCA could not be stimulated by addition of various carbon sources and it was also persistent under aerobic conditions for one site. Reductive dehalogenation of 1,1,1-TCA to DCA was rapid when zerovalent iron was used, but conversion of DCA was much slower. (orig.)

  16. Biobased Organic Chemistry Laboratories as Sustainable Experiment Alternatives

    Science.gov (United States)

    Silverman, Julian R.

    2016-01-01

    As nonrenewable resources deplete and educators seek relevant interdisciplinary content for organic chemistry instruction, biobased laboratory experiments present themselves as potential alternatives to petroleum-based transformations, which offer themselves as sustainable variations on important themes. Following the principles of green chemistry…

  17. LABORATORY FLUME EXPERIMENT WITH A CODED STRUCTURED LIGHT SYSTEM

    Directory of Open Access Journals (Sweden)

    D. Akca

    2012-07-01

    Full Text Available The topography of inland deltas is influenced chiefly by the water-sediment balance in distributary channels and local evaporation and seepage rates. In a previous study, a reduced complexity model has been applied to simulate the process of inland delta formation. Results have been compared with the Okavango Delta, Botswana and with a laboratory experiment. Both in the macro scale and the micro scale cases, high quality digital elevation models (DEM are essential. This work elaborates the laboratory experiment where an artificial inland delta is generated on laboratory scale and its topography is measured using a Breuckmann 3D scanner. The space-time evolution of the inland delta is monitored in the consecutive DEM layers. Regarding the 1.0m x 1.0m x 0.3m size of the working area, better than 100 micron precision is achieved which gives a relative precision of 1/10 000. The entire 3D modelling workflow is presented in terms of scanning, co-registration, surface generation, editing, and visualization steps. The co-registered high resolution topographic data allows us to analyse the stratigraphy patterns of the experiment and gain quantitative insight into the spatio-temporal evolution of the delta formation process.

  18. Microcosm. The world of the smallest particles; Mikrokosmos. Die Welt der kleinsten Teilchen

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsch, Harald

    2012-07-01

    In order to understand, why all, what us surrounds, exists, -men, animals, plants, planets, the universe-, we must draw our eyes from the gigantic to the tiny. From the universe to the atom. From the macrocosm to the microcosm. There the physicists search for the formula, which can explain the structure of the world.

  19. Effects of acute gamma-irradiation on the aquatic microbial microcosm in comparison with chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Fuma, Shoichi, E-mail: fuma@nirs.go.j [Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Ishii, Nobuyoshi; Takeda, Hiroshi; Miyamoto, Kiriko; Yanagisawa, Kei [Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Doi, Kazutaka; Kawaguchi, Isao [Regulatory Sciences Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Tanaka, Nobuyuki [Environmental Chemistry Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Inamori, Yuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Polikarpov, Gennady G. [The A.O. Kovalevsky Institute of Biology of Southern Seas, Sevastopol 99011 (Ukraine)

    2009-12-15

    Effects of acute gamma-irradiation were investigated in the aquatic microcosm consisting of green algae (Chlorella sp. and Scenedesmus sp.) and a blue-green alga (Tolypothrix sp.) as producers; an oligochaete (Aeolosoma hemprichi), rotifers (Lecane sp. and Philodina sp.) and a ciliate protozoan (Cyclidium glaucoma) as consumers; and more than four species of bacteria as decomposers. At 100 Gy, populations were not affected in any taxa. At 500-5000 Gy, one or three taxa died out and populations of two or three taxa decreased over time, while that of Tolypothrix sp. increased. This Tolypothrix sp. increase was likely an indirect effect due to interspecies interactions. The principal response curve analysis revealed that the main trend of the effects was a dose-dependent population decrease. For a better understanding of radiation risks in aquatic microbial communities, effect doses of gamma-rays compared with copper, herbicides and detergents were evaluated using the radiochemoecological conceptual model and the effect index for microcosm.

  20. Effects of acute γ-irradiation on the aquatic microbial microcosm in comparison with chemicals

    International Nuclear Information System (INIS)

    Fuma, Shoichi; Ishii, Nobuyoshi; Takeda, Hiroshi; Miyamoto, Kiriko; Yanagisawa, Kei; Doi, Kazutaka; Kawaguchi, Isao; Tanaka, Nobuyuki; Inamori, Yuhei; Polikarpov, Gennady G.

    2009-01-01

    Effects of acute γ-irradiation were investigated in the aquatic microcosm consisting of green algae (Chlorella sp. and Scenedesmus sp.) and a blue-green alga (Tolypothrix sp.) as producers; an oligochaete (Aeolosoma hemprichi), rotifers (Lecane sp. and Philodina sp.) and a ciliate protozoan (Cyclidium glaucoma) as consumers; and more than four species of bacteria as decomposers. At 100 Gy, populations were not affected in any taxa. At 500-5000 Gy, one or three taxa died out and populations of two or three taxa decreased over time, while that of Tolypothrix sp. increased. This Tolypothrix sp. increase was likely an indirect effect due to interspecies interactions. The principal response curve analysis revealed that the main trend of the effects was a dose-dependent population decrease. For a better understanding of radiation risks in aquatic microbial communities, effect doses of γ-rays compared with copper, herbicides and detergents were evaluated using the radiochemoecological conceptual model and the effect index for microcosm.

  1. Microbial Community and Functional Gene Changes in Arctic Tundra Soils in a Microcosm Warming Experiment

    Directory of Open Access Journals (Sweden)

    Ziming Yang

    2017-09-01

    Full Text Available Microbial decomposition of soil organic carbon (SOC in thawing Arctic permafrost is important in determining greenhouse gas feedbacks of tundra ecosystems to climate. However, the changes in microbial community structure during SOC decomposition are poorly known. Here we examine these changes using frozen soils from Barrow, Alaska, USA, in anoxic microcosm incubation at −2 and 8°C for 122 days. The functional gene array GeoChip was used to determine microbial community structure and the functional genes associated with SOC degradation, methanogenesis, and Fe(III reduction. Results show that soil incubation after 122 days at 8°C significantly decreased functional gene abundance (P < 0.05 associated with SOC degradation, fermentation, methanogenesis, and iron cycling, particularly in organic-rich soil. These observations correspond well with decreases in labile SOC content (e.g., reducing sugar and ethanol, methane and CO2 production, and Fe(III reduction. In contrast, the community functional structure was largely unchanged in the −2°C incubation. Soil type (i.e., organic vs. mineral and the availability of labile SOC were among the most significant factors impacting microbial community structure. These results demonstrate the important roles of microbial community in SOC degradation and support previous findings that SOC in organic-rich Arctic tundra is highly vulnerable to microbial degradation under warming.

  2. Review of recent experiments on magnetic reconnection in laboratory plasmas

    International Nuclear Information System (INIS)

    Yamada, M.

    1995-02-01

    The present paper reviews recent laboratory experiments on magnetic reconnection. Examples will be drawn from electron current sheet experiments, merging spheromaks, and from high temperature tokamak plasmas with the Lundquist numbers exceeding 10 7 . These recent laboratory experiments create an environment which satisfies the criteria for MHD plasma and in which the global boundary conditions can be controlled externally. Experiments with fully three dimensional reconnection are now possible. In the most recent TFTR tokamak discharges, Motional Stark effect (MSE) data have verified the existence of a partial reconnection. In the experiment of spheromak merging, a new plasma acceleration parallel to the neutral line has been indicated. Together with the relationship of these observations to the analysis of magnetic reconnection in space and in solar flares, important physics issues such as global boundary conditions, local plasma parameters, merging angle of the field lines, and the 3-D aspects of the reconnection are discussed

  3. Impact of redox-stratification on the diversity and distribution of bacterial communities in sandy reef sediments in a microcosm

    Institute of Scientific and Technical Information of China (English)

    GAO Zheng; WANG Xin; Angelos K. HANNIDES; Francis J. SANSONE; WANG Guangyi

    2011-01-01

    Relationships between microbial communities and geochemical environments are important in marine microbial ecology and biogeochemistry.Although biogeochemical redox stratification has been well documented in marine sediments,its impact on microbial communities remains largely unknown.In this study,we applied denaturing gradient gel electrophoresis (DGGE) and clone library construction to investigate the diversity and stratification of bacterial communities in redox-stratified sandy reef sediments in a microcosm.A total of 88 Operational Taxonomic Units (OTU) were identified from 16S rRNA clone libraries constructed from sandy reef sediments in a laboratory microcosm.They were members of nine phyla and three candidate divisions,including Proteobacteria (Alpha-,Beta-,Gamma-,Delta-,and Epsilonproteobacteria),Actinobacteria,Acidobacteria,Bacteroidetes,Chloroflexi,Cyanobacteria,Firmicutes,Verrucomicrobia,Spirochaetes,and the candidate divisions WS3,SO31 and AO19.The vast majority of these phylotypes are related to clone sequences from other marine sediments,but OTUs of Epsilonproteobacteria and WS3 are reported for the first time from permeable marine sediments.Several other OTUs are potential new bacterial phylotypes because of their low similarity with reference sequences.Results from the 16S rRNA,gene clone sequence analyses suggested that bacterial communities exhibit clear stratification across large redox gradients in these sediments,with the highest diversity found in the anoxic layer (15-25 mm) and the least diversity in the suboxic layer (3-5 mm).Analysis of the nosZ,and amoA gene libraries also indicated the stratification of denitrifiers and nitrifiers,with their highest diversity being in the anoxic and oxic sediment layers,respectively.These results indicated that redox-stratification can affect the distribution of bacterial communities in sandy reef sediments.

  4. OpenLabs Security Laboratory - The Online Security Experiment Platform

    OpenAIRE

    Johan Zackrisson; Charlie Svahnberg

    2008-01-01

    For experiments to be reproducible, it is important to have a known and controlled environment. This requires isolation from the surroundings. For security experiments, e.g. with hostile software, this is even more important as the experiment can affect the environment in adverse ways. In a normal campus laboratory, isolation can be achieved by network separation. For an online environment, where remote control is essential, separation and isolation are still needed, and therefore the securit...

  5. Zero-gravity cloud physics laboratory: Candidate experiments definition and preliminary concept studies

    Science.gov (United States)

    Eaton, L. R.; Greco, R. V.; Hollinden, A. B.

    1973-01-01

    The candidate definition studies on the zero-g cloud physics laboratory are covered. This laboratory will be an independent self-contained shuttle sortie payload. Several critical technology areas have been identified and studied to assure proper consideration in terms of engineering requirements for the final design. Areas include chambers, gas and particle generators, environmental controls, motion controls, change controls, observational techniques, and composition controls. This unique laboratory will allow studies to be performed without mechanical, aerodynamics, electrical, or other type techniques to support the object under study. This report also covers the candidate experiment definitions, chambers and experiment classes, laboratory concepts and plans, special supporting studies, early flight opportunities and payload planning data for overall shuttle payload requirements assessments.

  6. Einstein-Podolsky-Rosen-Bohm laboratory experiments : Data analysis and simulation

    NARCIS (Netherlands)

    De Raedt, H.; Michielsen, K.; Jin, F.; DAriano, M; Fei, SM; Haven, E; Hiesmayr, B; Jaeger, G; Khrennikov, A; Larsson, JA

    2012-01-01

    Data produced by laboratory Einstein-Podolsky-Rosen-Bohm (EPRB) experiments is tested against the hypothesis that the statistics of this data is given by quantum theory of this thought experiment. Statistical evidence is presented that the experimental data, while violating Bell inequalities, does

  7. The Role of Laboratory Experiments in the Validation of Field Data

    DEFF Research Database (Denmark)

    Mouneyrac, Catherine; Lagarde, Fabienne; Chatel, Amelie

    2017-01-01

    The ubiquitous presence and persistency of microplastics (MPs) in aquatic environments are of particular concern, since they constitute a potential threat to marine organisms and ecosystems. However, evaluating this threat and the impacts of MP on aquatic organisms is challenging. MPs form a very...... and to what degree these complexities are addressed in the current literature, to: (1) evaluate how well laboratory studies, investigated so far, represent environmentally relevant processes and scenarios and (2) suggest directions for future research The Role of Laboratory Experiments in the Validation...... of Field Data | Request PDF. Available from: https://www.researchgate.net/publication/310360438_The_Role_of_Laboratory_Experiments_in_the_Validation_of_Field_Data [accessed Jan 15 2018]....

  8. Drained coastal peatlands: A potential nitrogen source to marine ecosystems under prolonged drought and heavy storm events-A microcosm experiment.

    Science.gov (United States)

    Wang, Hongjun; Richardson, Curtis J; Ho, Mengchi; Flanagan, Neal

    2016-10-01

    Over the past several decades there has been a massive increase in coastal eutrophication, which is often caused by increased runoff input of nitrogen from landscape alterations. Peatlands, covering 3% of land area, have stored about 12-21% of global soil organic nitrogen (12-20Pg N) around rivers, lakes and coasts over millennia and are now often drained and farmed. Their huge nitrogen pools may be released by intensified climate driven hydrologic events-prolonged droughts followed by heavy storms-and later transported to marine ecosystems. In this study, we collected peat monoliths from drained, natural, and restored coastal peatlands in the Southeastern U.S., and conducted a microcosm experiment simulating coupled prolonged-drought and storm events to (1) test whether storms could trigger a pulse of nitrogen export from drought-stressed peatlands and (2) assess how differentially hydrologic managements through shifting plant communities affect nitrogen export by combining an experiment of nitrogen release from litter. During the drought phase, we observed a significant temporal variation in net nitrogen mineralization rate (NMR). NMR spiked in the third month and then decreased rapidly. This pattern indicates that drought duration significantly affects nitrogen mineralization in peat. NMR in the drained site reached up to 490±110kgha(-1)year(-1), about 5 times higher than in the restored site. After the 14-month drought phase, we simulated a heavy storm by bringing peat monoliths to saturation. In the discharge waters, concentrations of total dissolved nitrogen in the monoliths from the drained site (72.7±16.3mgL(-1)) was about ten times as high as from the restored site. Our results indicate that previously drained peatlands under prolonged drought are a potent source of nitrogen export. Moreover, drought-induced plant community shifts to herbaceous plants substantially raise nitrogen release with lasting effects by altering litter quality in peatlands

  9. Chemistry Graduate Teaching Assistants' Experiences in Academic Laboratories and Development of a Teaching Self-image

    Science.gov (United States)

    Gatlin, Todd Adam

    Graduate teaching assistants (GTAs) play a prominent role in chemistry laboratory instruction at research based universities. They teach almost all undergraduate chemistry laboratory courses. However, their role in laboratory instruction has often been overlooked in educational research. Interest in chemistry GTAs has been placed on training and their perceived expectations, but less attention has been paid to their experiences or their potential benefits from teaching. This work was designed to investigate GTAs' experiences in and benefits from laboratory instructional environments. This dissertation includes three related studies on GTAs' experiences teaching in general chemistry laboratories. Qualitative methods were used for each study. First, phenomenological analysis was used to explore GTAs' experiences in an expository laboratory program. Post-teaching interviews were the primary data source. GTAs experiences were described in three dimensions: doing, knowing, and transferring. Gains available to GTAs revolved around general teaching skills. However, no gains specifically related to scientific development were found in this laboratory format. Case-study methods were used to explore and illustrate ways GTAs develop a GTA self-image---the way they see themselves as instructors. Two general chemistry laboratory programs that represent two very different instructional frameworks were chosen for the context of this study. The first program used a cooperative project-based approach. The second program used weekly, verification-type activities. End of the semester interviews were collected and served as the primary data source. A follow-up case study of a new cohort of GTAs in the cooperative problem-based laboratory was undertaken to investigate changes in GTAs' self-images over the course of one semester. Pre-semester and post-semester interviews served as the primary data source. Findings suggest that GTAs' construction of their self-image is shaped through the

  10. Ecological effects of Spring and late Summer applications of Lambda-Cyhalothrin on freshwater microcosms

    NARCIS (Netherlands)

    Wijngaarden, van R.P.A.; Brock, T.C.M.; Brink, van den P.J.; Gylstra, R.; Maund, S.J.

    2006-01-01

    The aim of the study was to compare the effects of the pyrethroid insecticide lambda-cyhalothrin (treated at 10, 25, 50, 100, 250 ng active ingredient a.i./L) on a drainage ditch ecosystem in spring and late summer. Microcosms (water volume approximately 430 L) were established using enclosures in a

  11. Green Fluorescent Protein-Focused Bioinformatics Laboratory Experiment Suitable for Undergraduates in Biochemistry Courses

    Science.gov (United States)

    Rowe, Laura

    2017-01-01

    An introductory bioinformatics laboratory experiment focused on protein analysis has been developed that is suitable for undergraduate students in introductory biochemistry courses. The laboratory experiment is designed to be potentially used as a "stand-alone" activity in which students are introduced to basic bioinformatics tools and…

  12. The in vitro effect of Antimicrobial Photodynamic Therapy on dental microcosm biofilms from partially erupted permanent molars: A pilot study.

    Science.gov (United States)

    de Oliveira, Fabiana Sodré; Cruvinel, Thiago; Cusicanqui Méndez, Daniela Alejandra; Dionísio, Evandro José; Rios, Daniela; Machado, Maria Aparecida Andrade Moreira

    2018-03-01

    Antimicrobial Photodynamic Therapy (aPDT) could enhance the prevention of dental caries lesions in pits and fissures of partially erupted molars, by killing microorganisms from complex dental biofilms. This pilot study aimed to evaluate the effect of Antimicrobial Photodynamic Therapy (aPDT) on the viability of specific microorganism groups of dental microcosm biofilms from occlusal surfaces of first permanent molars in eruption. Dental microcosm biofilms grown on bovine enamel blocks, from dental plaque collected on occlusal surfaces of a partially erupted lower right first permanent molar, with McBain medium plus 1% sucrose in anaerobic condition at 37 °C for 72 h. The experiments were performed in eight groups: L-P- = no treatment (control), L18.75P- = 18.75 J/cm 2 LED, L37.5P- = 37.5 J/cm 2 LED, L75P- = 75 J/cm 2 LED, L-P+ = 200 mM TBO, L18.75P+ = 200 mM TBO + 18.75 J/cm 2 LED, L37.5P+ = 200 mM TBO + 37.5 J/cm 2 LED, and L75P+ = 200 mM TBO + 75 J/cm 2 LED. The counts of total microorganisms, total streptococci and mutans streptococci were determined on selective media agar plates by colony-forming units per mL. The log-transformed counts were analyzed by Kruskal-Wallis and post-hoc Dunn's test (P < 0.05). The counts of all microorganisms treated in the group L75P+ were statistically lower than those treated in L-P-. The aPDT promoted a significant reduction of microorganisms, with a trend of dose-dependent effect. TBO-mediated aPDT was effective in reducing the viability of specific microbial groups in dental microcosm biofilms originated from occlusal of permanent molars in eruption. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Glycosidation of Methanol with Ribose: An Interdisciplinary Undergraduate Laboratory Experiment

    Science.gov (United States)

    Simon, Erin; Cook, Katie; Pritchard, Meredith R.; Stripe, Wayne; Bruch, Martha; Bendinskas, Kestutis

    2010-01-01

    This exercise provides students hands-on experience with the topics of glycosidation, hemiacetal and acetal formation, proton nuclear magnetic resonance ([superscript 1]H NMR) spectroscopy, and kinetic and thermodynamic product formation. In this laboratory experiment, the methyl acetal of ribose is synthesized, and the kinetic and thermodynamic…

  14. Women's Experiences in the Engineering Laboratory in Japan

    Science.gov (United States)

    Hosaka, Masako

    2014-01-01

    This qualitative study aims to examine Japanese women undergraduate engineering students' experiences of interacting with departmental peers of the same year in the laboratory setting by using interview data of 32 final-year students at two modestly selective national universities in Japan. Expectation state theory that explains unequal…

  15. Armor breakup and reformation in a degradational laboratory experiment

    OpenAIRE

    Orrú, Clara; Blom, Astrid; Uijttewaal, Wim S. J.

    2016-01-01

    Armor breakup and reformation was studied in a laboratory experiment using a trimodal mixture composed of a 1mm sand fraction and two gravel fractions (6 and 10mm). The initial bed was characterized by a stepwise downstream fining pattern (trimodal reach) and a downstream sand reach, and the experiment was conducted under conditions without sediment supply. In the initial stage of the experiment an armor formed over the trimodal reach. The formation of the armor under partial transport condit...

  16. Gamification of the Laboratory Experience to Encourage Student Engagement

    Directory of Open Access Journals (Sweden)

    Kevin Drace

    2013-08-01

    Full Text Available The American Society for Microbiology (ASM Task Force on Curriculum Guidelines for Undergraduate Microbiology Students published recommendations for introductory microbiology courses that suggest teaching specific skill sets in the laboratory beyond just fundamental knowledge and concepts of microbiology (6; however, students can sometimes view a skills-based laboratory experience as a task list of unrelated assignments to complete for a grade. Therefore, providing explicit connections throughout the lecture and laboratory exercises is critical for a truly integrated learning experience. Several pedagogical techniques can provide a coherent framework throughout a course. For example, case-based studies can connect lecture with laboratory skills and increase student engagement by applying newly developed knowledge and skills to tackle real-world simulations (2, 3. One reason that case-based studies succeed is that they can provide intrinsic motivations and an alternate purpose for students to engage with the material. A more recent trend in pedagogy involves using game design elements to increase student engagement and motivation. Gamification is the application of game design (accruing points or badges, reaching significant levels of accomplishment, or other reward elements in a non-game context to motivate or influence participation (1, 5. A natural extension of both of these methods is to gamify a case-based approach where a fictional scenario is presented for students to role-play as scientists using their developed skills to solve a complex problem. The typical microbiology laboratory, as described by the ASM Task Force, can easily incorporate game design elements without extensive modification of the exercises themselves. Instead, gamification involves structuring the lab in a way that gives the course a coherent and unified purpose. This ultimately allows the student to see how the principles and concepts of lecture and laboratory connect

  17. Chemical Remediation of Nickel(II) Waste: A Laboratory Experiment for General Chemistry Students

    Science.gov (United States)

    Corcoran, K. Blake; Rood, Brian E.; Trogden, Bridget G.

    2011-01-01

    This project involved developing a method to remediate large quantities of aqueous waste from a general chemistry laboratory experiment. Aqueous Ni(II) waste from a general chemistry laboratory experiment was converted into solid nickel hydroxide hydrate with a substantial decrease in waste volume. The remediation method was developed for a…

  18. Real-time laboratory exercises to test contingency plans for classical swine fever: experiences from two national laboratories

    DEFF Research Database (Denmark)

    Koenen, K.; Uttenthal, Åse; Meindl-Böhmer, A.

    2007-01-01

    In order to adequately and efficiently handle outbreaks of contagious diseases such as classical swine fever (CSF), foot and mouth disease or highly pathogenic avian influenza, competent authorities and the laboratories involved have to be well prepared and must be in possession of functioning....... It is essential that these plans are established during ‘peace-time’ and are reviewed regularly. This paper provides suggestions on how to perform laboratory exercises to test preparedness and describes the experiences of two national reference laboratories for CSF. The major lesson learnt was the importance...

  19. Accreditation experience of radioisotope metrology laboratory of Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Iglicki, A. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina)]. E-mail: iglicki@cae.cnea.gov.ar; Mila, M.I. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina)]. E-mail: mila@cae.cnea.gov.ar; Furnari, J.C. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina); Arenillas, P. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina); Cerutti, G. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina); Carballido, M. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina); Guillen, V. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina); Araya, X. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina); Bianchini, R. [Laboratorio de Metrologia de Radioisotopos, Comision Nacional de Energia Atomica (Argentina)

    2006-10-15

    This work presents the experience developed by the Radioisotope Metrology Laboratory (LMR), of the Argentine National Atomic Energy Commission (CNEA), as result of the accreditation process of the Quality System by ISO 17025 Standard. Considering the LMR as a calibration laboratory, services of secondary activity determinations and calibration of activimeters used in Nuclear Medicine were accredited. A peer review of the ({alpha}/{beta})-{gamma} coincidence system was also carried out. This work shows in detail the structure of the quality system, the results of the accrediting audit and gives the number of non-conformities detected and of observations made which have all been resolved.

  20. Accreditation experience of radioisotope metrology laboratory of Argentina

    International Nuclear Information System (INIS)

    Iglicki, A.; Mila, M.I.; Furnari, J.C.; Arenillas, P.; Cerutti, G.; Carballido, M.; Guillen, V.; Araya, X.; Bianchini, R.

    2006-01-01

    This work presents the experience developed by the Radioisotope Metrology Laboratory (LMR), of the Argentine National Atomic Energy Commission (CNEA), as result of the accreditation process of the Quality System by ISO 17025 Standard. Considering the LMR as a calibration laboratory, services of secondary activity determinations and calibration of activimeters used in Nuclear Medicine were accredited. A peer review of the (α/β)-γ coincidence system was also carried out. This work shows in detail the structure of the quality system, the results of the accrediting audit and gives the number of non-conformities detected and of observations made which have all been resolved

  1. Using an Online Remote Laboratory for Electrical Experiments in Upper Secondary Education

    Directory of Open Access Journals (Sweden)

    Lars Håkansson

    2012-03-01

    Full Text Available The use of remote laboratories in courses at university level has been reported in literature numerous times since the mid 90’s. In this article focus is on activities carried out by teachers and students, at the Upper Secondary School Level, using the remote laboratory VISIR (Virtual Instrument Systems in Reality. The Upper Secondary School, Katedralskolan in Lund, Sweden, cooperate with Blekinge Institute of Technology, Sweden, in a project that concerns the introduction of remote laboratory environment suitable for Upper Secondary School science courses. A remote laboratory in electronics has been introduced and is used as a complement to the traditional workbench in the hands-on laboratory. Significant results from the project are; 1 the great interest shown by the students for the remote experiments, 2 the students appreciation for the fact that it was not simulations but actual real experiments, 3 the remote laboratory is easy to implement for use by both teachers and students and 4 it can be used simultaneously by many students.

  2. Aquatic risk assessment of a realistic exposure to pesticides used in bulb crops: a microcosm study

    NARCIS (Netherlands)

    Wijngaarden, van R.P.A.; Cuppen, J.G.M.; Arts, G.H.P.; Crum, S.J.H.; Hoorn, van den M.W.; Brink, van den P.J.; Brock, T.C.M.

    2004-01-01

    The fungicide fluazinam, the insecticide lambda-cyhalothrin, and the herbicides asulam and metamitron were applied to indoor freshwater microcosms (water volume approximately 0.6 m3). The treatment regime was based on a realistic application scenario in tulip cultivation. Concentrations of each

  3. ISO 15189 accreditation: Requirements for quality and competence of medical laboratories, experience of a laboratory I.

    Science.gov (United States)

    Guzel, Omer; Guner, Ebru Ilhan

    2009-03-01

    Medical laboratories are the key partners in patient safety. Laboratory results influence 70% of medical diagnoses. Quality of laboratory service is the major factor which directly affects the quality of health care. The clinical laboratory as a whole has to provide the best patient care promoting excellence. International Standard ISO 15189, based upon ISO 17025 and ISO 9001 standards, provides requirements for competence and quality of medical laboratories. Accredited medical laboratories enhance credibility and competency of their testing services. Our group of laboratories, one of the leading institutions in the area, had previous experience with ISO 9001 and ISO 17025 Accreditation at non-medical sections. We started to prepared for ISO 15189 Accreditation at the beginning of 2006 and were certified in March, 2007. We spent more than a year to prepare for accreditation. Accreditation scopes of our laboratory were as follows: clinical chemistry, hematology, immunology, allergology, microbiology, parasitology, molecular biology of infection serology and transfusion medicine. The total number of accredited tests is 531. We participate in five different PT programs. Inter Laboratory Comparison (ILC) protocols are performed with reputable laboratories. 82 different PT Program modules, 277 cycles per year for 451 tests and 72 ILC program organizations for remaining tests have been performed. Our laboratory also organizes a PT program for flow cytometry. 22 laboratories participate in this program, 2 cycles per year. Our laboratory has had its own custom made WEB based LIS system since 2001. We serve more than 500 customers on a real time basis. Our quality management system is also documented and processed electronically, Document Management System (DMS), via our intranet. Preparatory phase for accreditation, data management, external quality control programs, personnel related issues before, during and after accreditation process are presented. Every laboratory has

  4. Experience of maintaining laboratory educational website′s sustainability

    Directory of Open Access Journals (Sweden)

    Izak B Dimenstein

    2016-01-01

    Full Text Available Laboratory methodology websites are specialized niche websites. The visibility of a niche website transforms it into an authority site on a particular "niche of knowledge." This article presents some ways in which a laboratory methodology website can maintain its sustainability. The optimal composition of the website includes a basic content, a blog, and an ancillary part. This article discusses experimenting with the search engine optimization query results page. Strategic placement of keywords and even phrases, as well as fragmentation of the post′s material, can improve the website′s visibility to search engines. Hyperlinks open a chain reaction of additional links and draw attention to the previous posts. Publications in printed periodicals are a substantial part of a niche website presence on the Internet. Although this article explores a laboratory website on the basis of our hands-on expertise maintaining "Grossing Technology in Surgical Pathology" (www.grossing-technology.com website with a high volume of traffic for more than a decade, the recommendations presented here for developing an authority website can be applied to other professional specialized websites. The authority websites visibility and sustainability are preconditions for aggregating them in a specialized educational laboratory portal.

  5. Effects of the pyrethroid insecticide gamma-cyhalothrin on aquatic invertebrates in laboratory and outdoor microcosm tests

    NARCIS (Netherlands)

    Wijngaarden, van R.P.A.; Barber, I.; Brock, T.C.M.

    2009-01-01

    The sensitivity of a range of freshwater lentic invertebrates to gamma-cyhalothrin (GCH), a single enantiomer of the synthetic pyrethroid lambda-cyhalothrin, was assessed in single species laboratory tests and an outdoor multi-species ecosystem test. The most sensitive species in the laboratory

  6. Simulated and Virtual Science Laboratory Experiments: Improving Critical Thinking and Higher-Order Learning Skills

    Science.gov (United States)

    Simon, Nicole A.

    Virtual laboratory experiments using interactive computer simulations are not being employed as viable alternatives to laboratory science curriculum at extensive enough rates within higher education. Rote traditional lab experiments are currently the norm and are not addressing inquiry, Critical Thinking, and cognition throughout the laboratory experience, linking with educational technologies (Pyatt & Sims, 2007; 2011; Trundle & Bell, 2010). A causal-comparative quantitative study was conducted with 150 learners enrolled at a two-year community college, to determine the effects of simulation laboratory experiments on Higher-Order Learning, Critical Thinking Skills, and Cognitive Load. The treatment population used simulated experiments, while the non-treatment sections performed traditional expository experiments. A comparison was made using the Revised Two-Factor Study Process survey, Motivated Strategies for Learning Questionnaire, and the Scientific Attitude Inventory survey, using a Repeated Measures ANOVA test for treatment or non-treatment. A main effect of simulated laboratory experiments was found for both Higher-Order Learning, [F (1, 148) = 30.32,p = 0.00, eta2 = 0.12] and Critical Thinking Skills, [F (1, 148) = 14.64,p = 0.00, eta 2 = 0.17] such that simulations showed greater increases than traditional experiments. Post-lab treatment group self-reports indicated increased marginal means (+4.86) in Higher-Order Learning and Critical Thinking Skills, compared to the non-treatment group (+4.71). Simulations also improved the scientific skills and mastery of basic scientific subject matter. It is recommended that additional research recognize that learners' Critical Thinking Skills change due to different instructional methodologies that occur throughout a semester.

  7. Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms

    Energy Technology Data Exchange (ETDEWEB)

    Bombach, Petra, E-mail: petra.bombach@ufz.de [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Isodetect GmbH Leipzig, Deutscher Platz 5b, D-04103 Leipzig (Germany); Nägele, Norbert [Kuvier the Biotech Company S.L., Ctra. N-I, p.k. 234–P.E. INBISA 23" a, E-09001 Burgos (Spain); Rosell, Mònica [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristallografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), C/Martí i Franquès s/n, 08028 Barcelona (Spain); Richnow, Hans H. [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Fischer, Anko [Isodetect GmbH Leipzig, Deutscher Platz 5b, D-04103 Leipzig (Germany)

    2015-04-09

    Highlights: • In situ biodegradation of ETBE was investigated in a fuel contaminated aquifer. • Degradation was studied by CSIA and in situ microcosms in combination with TLFA-SIP. • ETBE was degraded when ETBE was the main groundwater contaminant. • ETBE was also degraded in the presence of BTEX and MTBE. • Hydrochemical analysis indicated aerobic and anaerobic ETBE biodegradation. - Abstract: Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [{sup 13}C{sub 6}]-ETBE (BACTRAP{sup ®}s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant {sup 13}C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation.

  8. Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms

    International Nuclear Information System (INIS)

    Bombach, Petra; a, E-09001 Burgos (Spain))" data-affiliation=" (Kuvier the Biotech Company S.L., Ctra. N-I, p.k. 234–P.E. INBISA 23a, E-09001 Burgos (Spain))" >Nägele, Norbert; Rosell, Mònica; Richnow, Hans H.; Fischer, Anko

    2015-01-01

    Highlights: • In situ biodegradation of ETBE was investigated in a fuel contaminated aquifer. • Degradation was studied by CSIA and in situ microcosms in combination with TLFA-SIP. • ETBE was degraded when ETBE was the main groundwater contaminant. • ETBE was also degraded in the presence of BTEX and MTBE. • Hydrochemical analysis indicated aerobic and anaerobic ETBE biodegradation. - Abstract: Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [ 13 C 6 ]-ETBE (BACTRAP ® s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant 13 C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation

  9. Microbiological and Hydrogeochemical Controls on Anaerobic Biodegradation of Petroleum Hydrocarbons: Case Study from Fort McCoy, WI

    Science.gov (United States)

    Schreiber, M. E.; Zwolinski, M. D.; Taglia, P. J.; Bahr, J. M.; Hickey, W. J.

    2001-05-01

    We are investigating the role of anaerobic processes that control field-scale BTEX loss using a variety of experimental and numerical techniques. Tracer tests, laboratory microcosms, and in situ microcosms (ISMs) were designed to examine BTEX biodegradation under intrinsic and enhanced anaerobic conditions in a BTEX plume at Fort McCoy, WI. In the tracer tests, addition of nitrate resulted in loss of toluene, ethylbenzene, and m, p-xylenes but not benzene. Laboratory microcosm and ISM experiments confirmed that nitrate addition is not likely to enhance benzene biodegradation at the site. Excess nitrate losses were observed in both field and laboratory experiments, indicating that reliance on theoretical stoichiometric equations to estimate contaminant mass losses should be re-evaluated. To examine changes in microbial community during biodegradation of BTEX under enhanced nitrate-reducing conditions, DNA was extracted from laboratory microcosm sediment, the 16S-rRNA gene was amplified using eubacterial primers, and products were separated by denaturing gradient gel electrophoresis. Banding patterns suggest that nitrate caused more of a community change than BTEX. These data suggest that nitrate plays an important role in microbial population selection. Numerical simulations were conducted to simulate the evolution of the BTEX plume and to quantify BTEX losses due to intrinsic and nitrate-enhanced biodegradation. Results suggest that the majority of intrinsic BTEX mass loss has occurred under aerobic and iron-reducing conditions. Due to depletion of solid-phase Fe(III) over time, however, future BTEX losses under iron-reducing conditions will decrease, and methanogenesis will play an increasingly important role in controlling biodegradation. The simulations also suggest that although nitrate addition will decrease TEX concentrations, source removal with intrinsic biodegradation is likely the most effective treatment method for the site.

  10. Effects of imidacloprid on the ecology of sub-tropical freshwater microcosms.

    Science.gov (United States)

    Sumon, Kizar Ahmed; Ritika, Afifat Khanam; Peeters, Edwin T H M; Rashid, Harunur; Bosma, Roel H; Rahman, Md Shahidur; Fatema, Mst Kaniz; Van den Brink, Paul J

    2018-05-01

    The neonicotinoid insecticide imidacloprid is used in Bangladesh for a variety of crop protection purposes. Imidacloprid may contaminate aquatic ecosystems via spray drift, surface runoff and ground water leaching. The present study aimed at assessing the fate and effects of imidacloprid on structural (phytoplankton, zooplankton, macroinvertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater, sub-tropical ecosystems in Bangladesh. Imidacloprid was applied weekly to 16 freshwater microcosms (PVC tanks containing 400 L de-chlorinated tap water) at nominal concentrations of 0, 30, 300, 3000 ng/L over a period of 4 weeks. Results indicated that imidacloprid concentrations from the microcosm water column declined rapidly. Univariate and multivariate analysis showed significant effects of imidacloprid on the zooplankton and macroinvertebrate community, some individual phytoplankton taxa, and water quality variables (i.e. DO, alkalinity, ammonia and nitrate), with Cloeon sp., Diaptomus sp. and Keratella sp. being the most affected species, i.e. showing lower abundance values in all treatments compared to the control. The observed high sensitivity of Cloeon sp. and Diaptomus sp. was confirmed by the results of single species tests. No significant effects were observed on the species composition of the phytoplankton, periphyton biomass and organic matter decomposition for any of the sampling days. Our study indicates that (sub-)tropical aquatic ecosystems can be much more sensitive to imidacloprid compared to temperate ones. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

    Directory of Open Access Journals (Sweden)

    S. D. Forestieri

    2016-07-01

    Full Text Available The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 % of predominately submicron SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs. One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. Optically weighted GF(85 % values for SSA particles were derived from measurements of light scattering and particle size distributions. The mean optically weighted SSA diameters were 530 and 570 nm for the indoor and outdoor MARTs, respectively. The GF(85 % measurements were made concurrently with online particle composition measurements, including bulk composition (using an Aerodyne high-resolution aerosol mass spectrometer and single particle (using an aerosol time-of-flight mass spectrometer measurement, and a variety of water-composition measurements. During both microcosm experiments, the observed optically weighted GF(85 % values were depressed substantially relative to pure inorganic sea salt by 5 to 15 %. There was also a time lag between GF(85 % depression and the peak chlorophyll a (Chl a concentrations by either 1 (indoor MART or 3-to-6 (outdoor MART days. The fraction of organic matter in the SSA particles generally increased after the Chl a peaked, also with a time lag, and ranged from about 0.25 to 0.5 by volume. The observed depression in the GF(85 % values (relative to pure sea salt is consistent with the large observed volume fractions of non-refractory organic matter (NR-OM comprising the SSA. The GF(85 % values

  12. Laboratory evaluation of biodegradation of crude oil contaminated tundra soil

    International Nuclear Information System (INIS)

    Schepart, B.S.; Hyzy, J.B.; Jorgenson, M.T.

    1992-01-01

    A laboratory experiment was designed to evaluate oil degradation rates in heavily contaminated soil samples from an oil spill site under various redox and nutrient conditions. Reduction of total petroleum hydrocarbons (TPH) in the experiment by indigenous bacteria was found to be negligible under aerobic conditions for all nutrient amendments over a 12-week period. The unexpectedly poor performance of the aerobic treatment may have been due to the high concentration of TPH (153,487 ppM) and the slow rate at which indigenous bacteria grew, or the preferential use of biogenic carbon over petroleum hydrocarbons. In contrast, under anaerobic conditions TPH was reduced by 47% in high nitrogen and phosphorous microcosms. The unexpectedly good performance of anaerobic bacteria indicates that promotion of oil degradation in saturated subsurface soils is feasible. The best degradation rates, however, were achieved by application of bacterial amendments, which reduced TPH up to 60% over 12 weeks. The higher degradation rates using bacterial amendments were attributed to the relatively rapid rate at which the bacteria colonized the substrates. This result suggests that bacterial additions in the field would be useful for promoting more rapid degradation of oil, while the slower growing indigenous oil-degrading bacteria population is allowed to increase. 19 refs., 9 figs., 3 tabs

  13. Differentiating Biochemistry Course Laboratories Based on Student Experience

    Science.gov (United States)

    Jakubowski, Henry V.

    2011-01-01

    Content and emphases in undergraduate biochemistry courses can be readily tailored to accommodate the standards of the department in which they are housed, as well as the backgrounds of the students in the courses. A more challenging issue is how to construct laboratory experiences for a class with both chemistry majors, who usually have little or…

  14. Detection of Salmonella enterica Serovar Montevideo and Newport in Free-ranging Sea Turtles and Beach Sand in the Caribbean and Persistence in Sand and Seawater Microcosms.

    Science.gov (United States)

    Ives, A-K; Antaki, E; Stewart, K; Francis, S; Jay-Russell, M T; Sithole, F; Kearney, M T; Griffin, M J; Soto, E

    2017-09-01

    Salmonellae are Gram-negative zoonotic bacteria that are frequently part of the normal reptilian gastrointestinal flora. The main objective of this project was to estimate the prevalence of non-typhoidal Salmonella enterica in the nesting and foraging populations of sea turtles on St. Kitts and in sand from known nesting beaches. Results suggest a higher prevalence of Salmonella in nesting leatherback sea turtles compared with foraging green and hawksbill sea turtles. Salmonella was cultured from 2/9 and identified by molecular diagnostic methods in 3/9 leatherback sea turtle samples. Salmonella DNA was detected in one hawksbill turtle, but viable isolates were not recovered from any hawksbill sea turtles. No Salmonella was detected in green sea turtles. In samples collected from nesting beaches, Salmonella was only recovered from a single dry sand sample. All recovered isolates were positive for the wzx gene, consistent with the O:7 serogroup. Further serotyping characterized serovars Montevideo and Newport present in cloacal and sand samples. Repetitive-element palindromic PCR (rep-PCR) fingerprint analysis and pulsed-field gel electrophoresis of the 2014 isolates from turtles and sand as well as archived Salmonella isolates recovered from leatherback sea turtles in 2012 and 2013, identified two distinct genotypes and four different pulsotypes, respectively. The genotyping and serotyping were directly correlated. To determine the persistence of representative strains of each serotype/genotype in these environments, laboratory-controlled microcosm studies were performed in water and sand (dry and wet) incubated at 25 or 35°C. Isolates persisted for at least 32 days in most microcosms, although there were significant decreases in culturable bacteria in several microcosms, with the greatest reduction in dry sand incubated at 35°C. This information provides a better understanding of the epizootiology of Salmonella in free-ranging marine reptiles and the potential

  15. A Low Cost Implementation of an Existing Hands-on Laboratory Experiment in Electronic Engineering

    Directory of Open Access Journals (Sweden)

    Clement Onime

    2014-10-01

    Full Text Available In engineering the pedagogical content of most formative programmes includes a significant amount of practical laboratory hands-on activity designed to deliver knowledge acquisition from actual experience alongside traditional face-to-face classroom based lectures and tutorials; this hands-on aspect is not always adequately addressed by current e-learning platforms. An innovative approach to e-learning in engineering, named computer aided engineering education (CAEE is about the use of computer aids for the enhanced, interactive delivery of educational materials in different fields of engineering through two separate but related components; one for classroom and another for practical hands-on laboratory work. The component for hands-on laboratory practical work focuses on the use of mixed reality (video-based augmented reality tools on mobile devices/platforms. This paper presents the computer aided engineering education (CAEE implementation of a laboratory experiment in micro-electronics that highlights some features such as the ability to closely implement an existing laboratory based hands-on experiment with lower associated costs and the ability to conduct the experiment off-line while maintaining existing pedagogical contents and standards.

  16. Microwave-Assisted Esterification: A Discovery-Based Microscale Laboratory Experiment

    Science.gov (United States)

    Reilly, Maureen K.; King, Ryan P.; Wagner, Alexander J.; King, Susan M.

    2014-01-01

    An undergraduate organic chemistry laboratory experiment has been developed that features a discovery-based microscale Fischer esterification utilizing a microwave reactor. Students individually synthesize a unique ester from known sets of alcohols and carboxylic acids. Each student identifies the best reaction conditions given their particular…

  17. Dynamics of fault slip near the stability transition combining laboratory and numerical experiments

    Science.gov (United States)

    Mele Veedu, D.; Giorgetti, C.; Scuderi, M. M.; Barbot, S.; Marone, C.; Collettini, C.

    2017-12-01

    Frictional stability controls the seismogenic potential of faults. Laboratory (1) and theoretical (2) studies document and predict the conditions under which fault slip is seismic or aseismic. However, the full gamut of fault slip behavior near the stable/unstable boundary is still poorly known. Here, we combine insight from laboratory and numerical experiments to identify the wide spectrum of frictional instabilities around that transition, including slow-slip events, period-multiplying events, and chaos. We present a synoptic picture of the dynamics of fault slip in a bifurcation diagram obtained from a series of laboratory and numerical experiments. We compare the laboratory observations with spring-slider and finite-fault numerical models. In the laboratory, we vary the stiffness of the system by modulating the stress field around the experimental fault. In the numerical experiments, we vary the characteristic weakening distance to explore a range of critical nucleation sizes. Contrarily to previously found (3), complex fault dynamics can be obtained with a rate-and-state constitutive law with a single state variable. While the dynamics of fault slip is complicated on large faults by the presence of morphological and rheological heterogeneities, the range of instabilities identified in the laboratory is reminiscent of the variety of slow and fast earthquakes found along subduction zones (4). The accord between laboratory data and theoretical models affords more realistic predictions of fault behavior at slow slip speeds. (1) Scuderi et al., (2016), (2) Ruina (1983), (3) Gu & Wong (1994), (4) Obara & Kato (2016)

  18. Effects of invertebrate predators and a pesticide on temporary pond microcosms used for aquatic toxicity testing

    International Nuclear Information System (INIS)

    Barry, Michael J.; Davies, Warren

    2004-01-01

    The effects of increased trophic complexity, through the addition of predatory notonectids (Anisops deanei), on temporary pond microcosms used for aquatic toxicity testing were studied. Replicate microcosms were established using sediment from a dried temporary pond, and treated with one of four concentrations of the organochlorine pesticide endosulfan (0, 1, 10 or 50 μg/L), in the presence or absence of six A. deanei. The tanks were sampled regularly for nine weeks following the addition of the predators and the entire contents of each tank counted after 12 weeks. Analysis using non-metric multidimensional scaling (MDS) and non-parametric MANOVA showed that both Anisops and endosulfan at concentrations >10 μg/L significantly altered community structure. However, an interaction between the effects of Anisops and the effects of endosulfan was not detected. The addition of Anisops did not increase the variability of response and thus did not reduce the sensitivity of the test method

  19. Survival behaviour and virulence of the fish pathogen Vibrio ordalii in seawater microcosms.

    Science.gov (United States)

    Ruiz, Pamela; Poblete-Morales, Matías; Irgang, Rute; Toranzo, Alicia E; Avendaño-Herrera, Ruben

    2016-06-15

    Vibrio ordalii, the causative agent of atypical vibriosis, is a Gram-negative, motile, rod-shaped bacterium that severely affects the salmonid aquaculture industry. V. ordalii has been biochemically, antigenically and genetically characterized. However, studies on the survival behaviour of this bacterium in aquatic environments are scarce, and there is no information regarding its disease transmission and infectious abilities outside of the fish host or regarding water as a possible reservoir. The present study investigated the survival behaviour of V. ordalii Vo-LM-06 and Vo-LM-18 in sterile and non-sterile seawater microcosms. After a year in sterile seawater without nutrients, 1% of both V. ordalii strains survived (~10(3) colony-forming units ml(-1)), and long-term maintenance did not affect bacterial biochemical or genetic properties. Additionally, V. ordalii maintained for 60 d in sterile seawater remained infective in rainbow trout Oncorhynchus mykiss. However, after 2 d of natural seawater exposure, this bacterium became non-culturable, indicating that autochthonous microbiota may play an important role in survival. Recuperation assays that added fresh medium to non-sterile microcosms did not favour V. ordalii recovery on solid media. Our results contribute towards a better understanding of V. ordalii survival behaviour in seawater ecosystems.

  20. A Global Remote Laboratory Experimentation Network and the Experiment Service Provider Business Model and Plans

    Directory of Open Access Journals (Sweden)

    Tor Ivar Eikaas

    2003-07-01

    Full Text Available This paper presents results from the IST KAII Trial project ReLAX - Remote LAboratory eXperimentation trial (IST 1999-20827, and contributes with a framework for a global remote laboratory experimentation network supported by a new business model. The paper presents this new Experiment Service Provider business model that aims at bringing physical experimentation back into the learning arena, where remotely operable laboratory experiments used in advanced education and training schemes are made available to a global education and training market in industry and academia. The business model is based on an approach where individual experiment owners offer remote access to their high-quality laboratory facilities to users around the world. The usage can be for research, education, on-the-job training etc. The access to these facilities is offered via an independent operating company - the Experiment Service Provider. The Experiment Service Provider offers eCommerce services like booking, access control, invoicing, dispute resolution, quality control, customer evaluation services and a unified Lab Portal.

  1. How (not) to design procurement mechanisms: A laboratory experiment

    NARCIS (Netherlands)

    Onderstal, S.; van de Meerendonk, A.

    2008-01-01

    In this paper, we examine the relative performance of three commonly used procurement mechanisms: price-only auctions, scoring auctions, and benchmarking. We do so both in theory and in a laboratory experiment. We find that the auctions yield the same level of welfare, and welfare dominate

  2. Clinical and laboratory experience of chorionic villous sampling in ...

    African Journals Online (AJOL)

    Background: Chorionic villous sampling is a first trimester invasive diagnosis procedure that was introduced in Nigeria <2 decades ago. Objective: The objective of the following study is to review experience with chorionic villous sampling in relation to clinical and laboratory procedures, including general characteristics of ...

  3. Effects of a herbicide-insecticide mixture in freshwater microcosms: Risk assessment and ecological effect chain

    International Nuclear Information System (INIS)

    Brink, Paul J. van den; Crum, Steven J.H.; Gylstra, Ronald; Bransen, Fred; Cuppen, Jan G.M.; Brock, Theo C.M.

    2009-01-01

    Effects of chronic application of a mixture of the herbicide atrazine and the insecticide lindane were studied in indoor freshwater plankton-dominated microcosms. The macroinvertebrate community was seriously affected at all but the lowest treatment levels, the zooplankton community at the three highest treatment levels, with crustaceans, caddisflies and dipterans being the most sensitive groups. Increased abundance of the phytoplankton taxa Cyclotella sp. was found at the highest treatment level. Threshold levels for lindane, both at population and community level, corresponded well with those reported in the literature. Atrazine produced fewer effects than expected, probably due to decreased grazer stress on the algae as a result of the lindane application. The safety factors set by the Uniform Principles for individual compounds were also found to ensure protection against chronic exposure to a mixture of a herbicide and insecticide at community level, though not always at the population level. - Effects of chronic application of a herbicide-insecticide mixture were studied in indoor freshwater plankton-dominated microcosms. Effects could well be explained by the effects of the individual chemicals alone, no synergetic effects were reported

  4. The laboratory of the mind thought experiments in the natural sciences

    CERN Document Server

    Brown, James Robert

    1993-01-01

    Thought experiments are performed in the laboratory of the mind. Beyond this metaphor it is difficult to say just what these remarkable devices for investigating nature are or how they work. Though most scientists and philosophers would admit their great importance, there has been very little serious study of them. This volume is the first book-length investigation of thought experiments. Starting with Galileo's argument on falling bodies, Brown describes numerous examples of the most influential thought experiments from the history of science. Following this introduction to the subject, some substantial and provocative claims are made, the principle being that some thought experiments should be understood in the same way that platonists understand mathematical activity: as an intellectual grasp of an independently existing abstract realm. With its clarity of style and structure, The Laboratory of the Mind will find readers among all philosophers of science as well as scientists who have puzzled over how thou...

  5. LOSS OF ORGANIC CHEMICALS IN SOIL: PURE COMPOUND TREATABILITY STUDIES

    Science.gov (United States)

    Comprehensive screening data on the treatability of 32 organic chemicals in soil were developed. Of the evaluated chemicals, 22 were phenolic compounds. Aerobic batch laboratory microcosm experiments were conducted using two soils: an acidic clay soil with <1% organic matter and ...

  6. Experiment using laboratory scale extruder. Fluid behavior in twin-screw extruder

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi; Miura, Akihiko

    1999-09-01

    All evidences and chemical data suggest non-chemical heating mechanism raised the filling temperature of the bituminized product. But they indicate the filling temperature was higher than before at the incident. We estimated the physical heat mechanism in the extruder. It is well known that the viscous-heating occurs in mixing process in extruders. In order to confirm the behavior of the torque and temperature, some experiment using laboratory scale extruder were performed. The result of the experiment using laboratory scale extruder showed that the phenomena of salt enrichment and salt accumulation were observed and they raised mixture temperature at the decreased feed rate. These phenomena depend on the feed rate. It is considered that they have large contribution to heat transportation and operational torque due to the friction between screw and mixture. In this report, all experiment result are explained. (author)

  7. From a microcosm to the catchment scale: studying the fate of organic runoff pollutants in aquatic ecosystems

    Science.gov (United States)

    Böttcher, T.; Schroll, R.

    2009-04-01

    Spray-drift, drainage, erosion and runoff events are the major causes responsible for deportation of agrochemicals as micropollutants to aquatic non-target sites. These processes can lead to the contamination of nearby freshwater ecosystems with considerably high concentrations of xenobiotics. Thus, it is important to unravel the fate of these pollutants and to evaluate their ecological effects. A novel approach to address this goal was established by the development of a microcosm with multiple sampling abilities enabling quantitative assessment of organic volatilisation, mineralization, metabolization and distribution within the aquatic ecosystem. This microcosm system was designed to support modelling approaches of the catchment scale and gain insights into the fate of pesticides simulating a large scale water body. The potential of this microcosm was exemplified for Isoproturon (IPU), a phenylurea derived systemic herbicide, which is frequently found as contaminant in water samples and with the free-floating macrophyte Lemna minor as non-target species, that is common to occur in rural water bodies. During 21 days exposure time, only a small amount of 14C labeled IPU was removed from the aquatic medium. The major portion (about 5%) was accumulated by Lemna minor resulting in a BCF of 15.8. IPU-volatilisation was very low with 0.13% of the initially applied herbicide. Only a minor amount of IPU was completely metabolized, presumably by rhizosphere microorganisms and released as 14CO2. The novel experimental system allowed to quantitatively investigate the fate of IPU and showed a high reproducibility with a mean average 14C-recovery rate of 97.1

  8. Site-specific variability in BTEX biodegradation under denitrifying conditions

    International Nuclear Information System (INIS)

    Kao, C.M.; Borden, R.C.

    1997-01-01

    Laboratory microcosm experiments were conducted to evaluate the feasibility of benzene, toluene, ethylbenzene, m-xylene, and o-xylene (BTEX) biodegradation under denitrifying conditions. Nine different sources of inocula, including contaminated and uncontaminated soil cores from four different sites and activated sludge, were used to establish microcosms. BTEX was not degraded under denitrifying conditions in microcosms inoculated with aquifer material from Rocky Point and Traverse City. However, rapid depletion of glucose under denitrifying conditions was observed in microcosms containing Rocky Point aquifer material. TEX degradation was observed in microcosms containing Rocky Point aquifer material. TEX degradation was observed in microcosms containing aquifer material from Fort Bragg and Sleeping Bear Dunes and sewage sludge. Benzene was recalcitrant in all microcosms tested. The degradation of o-xylene ceased after toluene, ethylbenzene, and m-xylene were depleted in the Fort Bragg and sludge microcosms, but o-xylene continued to degrade in microcosms with contaminated Sleeping Bear Dunes soil. The most probable number (MPN) of denitrifiers in these nine different inocula were measured using a microtiter technique. There was no correlation between the MPN of denitrifiers and the TEX degradation rate under denitrifying conditions. Experimental results indicate that the degradation sequence and TEX degradation rate under denitrifying conditions may differ among sites. Results also indicate that denitrification alone may not be a suitable bioremediation technology for gasoline-contaminated aquifers because of the inability of denitrifiers to degrade benzene

  9. Large scale laboratory diffusion experiments in clay rocks

    International Nuclear Information System (INIS)

    Garcia-Gutierrez, M.; Missana, T.; Mingarro, M.; Martin, P.L.; Cormenzana, J.L.

    2005-01-01

    Full text of publication follows: Clay formations are potential host rocks for high-level radioactive waste repositories. In clay materials the radionuclide diffusion is the main transport mechanism. Thus, the understanding of the diffusion processes and the determination of diffusion parameters in conditions as similar as possible to the real ones, are critical for the performance assessment of deep geological repository. Diffusion coefficients are mainly measured in the laboratory using small samples, after a preparation to fit into the diffusion cell. In addition, a few field tests are usually performed for confirming laboratory results, and analyse scale effects. In field or 'in situ' tests the experimental set-up usually includes the injection of a tracer diluted in reconstituted formation water into a packed off section of a borehole. Both experimental systems may produce artefacts in the determination of diffusion coefficients. In laboratory the preparation of the sample can generate structural change mainly if the consolidated clay have a layered fabric, and in field test the introduction of water could modify the properties of the saturated clay in the first few centimeters, just where radionuclide diffusion is expected to take place. In this work, a large scale laboratory diffusion experiment is proposed, using a large cylindrical sample of consolidated clay that can overcome the above mentioned problems. The tracers used were mixed with clay obtained by drilling a central hole, re-compacted into the hole at approximately the same density as the consolidated block and finally sealed. Neither additional treatment of the sample nor external monitoring are needed. After the experimental time needed for diffusion to take place (estimated by scoping calculations) the block was sampled to obtain a 3D distribution of the tracer concentration and the results were modelled. An additional advantage of the proposed configuration is that it could be used in 'in situ

  10. FEBEX II Project THG Laboratory Experiments

    International Nuclear Information System (INIS)

    Missana, T.

    2004-01-01

    The main roles of the bentonite in a radioactive waste repository is to act as a geochemical barrier against the radionuclides migration. The effectiveness of this geochemical barrier depends on the surface properties of the solid phases and on the physico-chemical environment generated by the interaction of the solid phases with the groundwater. Within the FEBEX (Full-scale Engineered Barriers Experiment) project, a program of laboratory tests was designed to study and to understand the processes taking place in the clay barrier. Since the first stages of the project, these laboratory tests enabled to isolate different processes, making easier their interpretation, and provided fundamental parameters to be used in the Thermo Hydro Mechanical (THM) and Thermo Hydro Geochemical (THG) models. Additionally, experimental data enabled to check the predictive capability of these models. In the second phase of the project, laboratory tests focused on all those relevant aspects not sufficiently covered during FEBEX I. Particularly, the following main objectives were proposed for the THG investigations during FEBEX II : Attainment of a reliable description of the pore water chemistry at different geochemical conditions. Identification of the different types of water present in the bentonite and to determine the amount of available water for the solute transport.Evaluation of the potential effects of the extraction pressure in the chemical composition of the water obtained by squeezing methods.Study of the effects of the exchange complex in the rheological properties of the clay.Identification and modelling of the surface processes occurring in smectite, determination of the solubility constants of smectite and the formation constants of the surface complexes.Understanding of the mechanisms involved in the sorption of different radionuclides in the bentonite. Investigation of the diffusion mechanisms of conservative neutral and anionic species to have a deeper insight on the

  11. FEBEX II Project THG Laboratory Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Missana, T.

    2004-07-01

    The main roles of the bentonite in a radioactive waste repository is to act as a geochemical barrier against the radionuclides migration. The effectiveness of this geochemical barrier depends on the surface properties of the solid phases and on the physico-chemical environment generated by the interaction of the solid phases with the groundwater. Within the FEBEX (Full-scale Engineered Barriers Experiment) project, a program of laboratory tests was designed to study and to understand the processes taking place in the clay barrier. Since the first stages of the project, these laboratory tests enabled to isolate different processes, making easier their interpretation, and provided fundamental parameters to be used in the Thermo Hydro Mechanical (THM) and Thermo Hydro Geochemical (THG) models. Additionally, experimental data enabled to check the predictive capability of these models. In the second phase of the project, laboratory tests focused on all those relevant aspects not sufficiently covered during FEBEX I. Particularly, the following main objectives were proposed for the THG investigations during FEBEX II : Attainment of a reliable description of the pore water chemistry at different geochemical conditions. Identification of the different types of water present in the bentonite and to determine the amount of available water for the solute transport.Evaluation of the potential effects of the extraction pressure in the chemical composition of the water obtained by squeezing methods.Study of the effects of the exchange complex in the rheological properties of the clay.Identification and modelling of the surface processes occurring in smectite, determination of the solubility constants of smectite and the formation constants of the surface complexes.Understanding of the mechanisms involved in the sorption of different radionuclides in the bentonite. Investigation of the diffusion mechanisms of conservative neutral and anionic species to have a deeper insight on the

  12. Fusion virtual laboratory: The experiments' collaboration platform in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, H., E-mail: nakanisi@nifs.ac.jp [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Kojima, M.; Takahashi, C.; Ohsuna, M.; Imazu, S.; Nonomura, M. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Hasegawa, M. [RIAM, Kyushu University, Kasuga, Fukuoka 816-8560 (Japan); Yoshikawa, M. [PRC, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Nagayama, Y.; Kawahata, K. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

    2012-12-15

    'Fusion virtual laboratory (FVL)' is the experiments' collaboration platform covering multiple fusion projects in Japan. Major Japanese fusion laboratories and universities are mutually connected through the dedicated virtual private network, named SNET, on SINET4. It has 3 different categories; (i) LHD remote participation, (ii) bilateral experiments' collaboration, and (iii) remote use of supercomputer. By extending the LABCOM data system developed at LHD, FVL supports (i) and (ii) so that it can deal with not only LHD data but also the data of two remote experiments: QUEST at Kyushu University and GAMMA10 at University of Tsukuba. FVL has applied the latest 'cloud' technology for both data acquisition and storage architecture. It can provide us high availability and performance scalability of the whole system. With a well optimized TCP data transferring method, the unified data access platform for both experimental data and numerical computation results could become realistic on FVL. The FVL project will continue demonstrating the ITER-era international collaboration schemes and the necessary technology.

  13. Microrelief-Controlled Overland Flow Generation: Laboratory and Field Experiments

    Directory of Open Access Journals (Sweden)

    Xuefeng Chu

    2015-01-01

    Full Text Available Surface microrelief affects overland flow generation and the related hydrologic processes. However, such influences vary depending on other factors such as rainfall characteristics, soil properties, and initial soil moisture conditions. Thus, in-depth research is needed to better understand and evaluate the combined effects of these factors on overland flow dynamics. The objective of this experimental study was to examine how surface microrelief, in conjunction with the factors of rainfall, soil, and initial moisture conditions, impacts overland flow generation and runoff processes in both laboratory and field settings. A series of overland flow experiments were conducted for rough and smooth surfaces that represented distinct microtopographic characteristics and the experimental data were analyzed and compared. Across different soil types and initial moisture conditions, both laboratory and field experiments demonstrated that a rough soil surface experienced a delayed initiation of runoff and featured a stepwise threshold flow pattern due to the microrelief-controlled puddle filling-spilling-merging dynamics. It was found from the field experiments that a smooth plot surface was more responsive to rainfall variations especially during an initial rainfall event. However, enhanced capability of overland flow generation and faster puddle connectivity of a rough field plot occurred during the subsequent rain events.

  14. Transformation of fault slip modes in laboratory experiments

    Science.gov (United States)

    Martynov, Vasilii; Alexey, Ostapchuk; Markov, Vadim

    2017-04-01

    Slip mode of crust fault can vary because of many reasons. It's well known that fault structure, material of fault gouge, pore fluid et al. in many ways determines slip modes from creep and slow slip events to mega-earthquakes [1-3]. Therefore, the possibility of fault slip transformation due to external action is urgent question. There is popular and developing approach of fluid injection into central part of fault. The phenomenon of earthquakes induced due to pumping of water was investigated on small and large scales [4, 5]. In this work the laboratory experiments were conducted to study the evolution of the experimental fault slip when changing the properties of the interstitial fluid. The scheme of experiments is the classical slider-model set-up, in which the block under the shear force slips along the interface. In our experiments the plexiglas block 8x8x3 cm3 in size was put on the plexiglas base. The contact of the blocks was filled with a thin layer (about 3 mm thick) of a granular material. The normal load varied from 31 to 156 kPa. The shear load was applied through a spring with stiffness 60 kN/m, and the rate of spring deformation was 20 or 5 mcm/s. Two parameters were recorded during experiments: the shear force acting on the upper block (with an accuracy of 1 N) and its displacement relatively the base (with an accuracy of 0.1 μm). The gouge was composed of quartz sand (97.5%) and clay (2.5%). As a moisturizer were used different fluids with viscosity varying from 1 to 103 mPa x s. Different slip modes were simulated during slider-experiments. In our experiments slip mode is the act of instability manifested in an increase of slip velocity and a drop of shear stress acting on a movable block. The amplitude of a shear stress drop and the peak velocity of the upper block were chosen as the characteristics of the slip mode. In the laboratory experiments, slip events of one type can be achieved either as regularly recurring (regular mode) or as random

  15. Nuclear astrophysics at Gran Sasso Laboratory: the LUNA experiment

    Science.gov (United States)

    Cavanna, Francesca

    2018-05-01

    LUNA is an experimental approach for the study of nuclear fusion reactions based on an underground accelerator laboratory. Aim of the experiment is the direct measurement of the cross section of nuclear reactions relevant for stellar and primordial nucleosynthesis. In the following the latest results and the future goals will be presented.

  16. Virtual geotechnical laboratory experiments using a simulator

    Science.gov (United States)

    Penumadu, Dayakar; Zhao, Rongda; Frost, David

    2000-04-01

    The details of a test simulator that provides a realistic environment for performing virtual laboratory experimentals in soil mechanics is presented. A computer program Geo-Sim that can be used to perform virtual experiments, and allow for real-time observations of material response is presented. The results of experiments, for a given set of input parameters, are obtained with the test simulator using well-trained artificial neural-network-based soil models for different soil types and stress paths. Multimedia capabilities are integrated in Geo-Sim, using software that links and controls a laser disc player with a real-time parallel processing ability. During the simulation of a virtual experiment, relevant portions of the video image of a previously recorded test on an actual soil specimen are dispalyed along with the graphical presentation of response from the feedforward ANN model predictions. The pilot simulator developed to date includes all aspects related to performing a triaxial test on cohesionless soil under undrained and drained conditions. The benefits of the test simulator are also presented.

  17. Guided-inquiry laboratory experiments to improve students' analytical thinking skills

    Science.gov (United States)

    Wahyuni, Tutik S.; Analita, Rizki N.

    2017-12-01

    This study aims to improve the experiment implementation quality and analytical thinking skills of undergraduate students through guided-inquiry laboratory experiments. This study was a classroom action research conducted in three cycles. The study has been carried out with 38 undergraduate students of the second semester of Biology Education Department of State Islamic Institute (SII) of Tulungagung, as a part of Chemistry for Biology course. The research instruments were lesson plans, learning observation sheets and undergraduate students' experimental procedure. Research data were analyzed using quantitative-descriptive method. The increasing of analytical thinking skills could be measured using gain score normalized and statistical paired t-test. The results showed that guided-inquiry laboratory experiments model was able to improve both the experiment implementation quality and the analytical thinking skills. N-gain score of the analytical thinking skills was increased, in spite of just 0.03 with low increase category, indicated by experimental reports. Some of undergraduate students have had the difficulties in detecting the relation of one part to another and to an overall structure. The findings suggested that giving feedback the procedural knowledge and experimental reports were important. Revising the experimental procedure that completed by some scaffolding questions were also needed.

  18. Survival, growth, and body residues of hyalella azteca (Saussure) exposed to fipronil contaminated sediments from non-vegetated and vegetated microcosms.

    Science.gov (United States)

    Kröger, Robert; Lizotte, Richard E; Moore, Matthew T

    2009-09-01

    We assessed chronic effects of fipronil and metabolite contaminated sediments from non-vegetated and Thallia dealbata vegetated wetland microcosms on Hyalella azteca during wet and dry exposures. Mean sediment concentrations (ng g(-1)) ranged from 0.72-1.26, 0.01-0.69, 0.07-0.23, and 0.49-7.87 for fipronil, fipronil-sulfide, fipronil-sulfone, and fipronil-desulfinyl, respectively. No significant differences in animal survival or growth were observed between non-vegetated and vegetated microcosms during wet or dry exposures. Mean animal body residue concentrations (ng g(-1)) ranged from 28.4-77.6, 0-30.7, and 8.3-43.8 for fipronil, fipronil-sulfide, and fipronil-sulfone. Fipronil-desulfinyl was not detected in any animal samples.

  19. Simulations of Laboratory Astrophysics Experiments using the CRASH code

    Science.gov (United States)

    Trantham, Matthew; Kuranz, Carolyn; Fein, Jeff; Wan, Willow; Young, Rachel; Keiter, Paul; Drake, R. Paul

    2015-11-01

    Computer simulations can assist in the design and analysis of laboratory astrophysics experiments. The Center for Radiative Shock Hydrodynamics (CRASH) at the University of Michigan developed a code that has been used to design and analyze high-energy-density experiments on OMEGA, NIF, and other large laser facilities. This Eulerian code uses block-adaptive mesh refinement (AMR) with implicit multigroup radiation transport, electron heat conduction and laser ray tracing. This poster will demonstrate some of the experiments the CRASH code has helped design or analyze including: Kelvin-Helmholtz, Rayleigh-Taylor, magnetized flows, jets, and laser-produced plasmas. This work is funded by the following grants: DEFC52-08NA28616, DE-NA0001840, and DE-NA0002032.

  20. Influence of phosphate and copper on reductive dechlorination of thiobencarb in California rice field soils.

    Science.gov (United States)

    Gunasekara, Amrith S; Tenbrook, Patti L; Palumbo, Amanda J; Johnson, Catherine S; Tjeerdema, Ronald S

    2005-12-28

    The potential for reductive dechlorination of the herbicide thiobencarb (TB) by microbes and its prevention in saturated anaerobic rice field soils was examined in laboratory microcosms. TB is effective in controlling both annual grasses and broadleaf weeds. In anoxic microcosms, TB was effectively degraded within 30 days to its dechlorinated product, deschlorothiobencarb (DTB), in two Sacramento Valley rice field soils. TB dechlorination, and subsequent degradation, followed pseudo-zero- (lag phase) and first-order (degradation phase) kinetics. Logistic regression analysis (r2 > 0.841) produced a half-life (t(1/2)) in nonsterile soils ranging from 10 to 15 days, which was also observed when microcosms were amended with low concentrations (copper (Cu2+; as the fungicides Cu(OH)2 and CuSO4.5H2O). High Cu2+ concentrations (>40 mg L(-1)) were added to the microcosms to determine if copper toxicity to dechlorinating microbes is concentration dependent within the range used. After 30 days, the low-copper-amended soils closely resembled the nonsterile experiments to which no Cu2+ was added while the high-copper-amended microcosms were similar to the sterile experiment. Microcosms were also separately amended with 5.7 g L(-1) phosphate (PO4(2-); as KH2PO4), a nutrient regularly applied to rice fields. Phosphate-amended experiments also showed TB degradation, but no DTB formation, indicating the phosphate played a role, possibly as a microbial inhibitor or an alternative electron acceptor, in limiting the dechlorination of TB. In summary, TB dechlorination was inhibited at high Cu(OH)2, CuSO4.5H2O, and KH2PO4 concentrations.

  1. Microcosm investigation of growth and phytoremediation potential of Azolla japonica along nitrogen gradients.

    Science.gov (United States)

    Park, Hun; Song, Uhram

    2017-10-03

    Although Azolla species are among the most promising plants for use in phytoremediation, more studies on their growth and nitrogen (N) uptake along the N gradients of growing media are required. In this study, N concentration-dependent growth in growing media and phosphorus (P) and N accumulation by Azolla japonica were studied by estimating direct N uptake from media by molybdenum-iron proteins. The doubling time of A. japonica was less than a week, regardless of the N concentration (0, 5, and 25 mg N/L) present in the growth media, indicating that this plant is suitable for remediation. Plants showed a high uptake of P, probably via plant-bacteria symbiosis, indicating their potential for effective P remediation. A. japonica also showed more than 4% N content regardless of the treatment and accumulated more than 40 mg of N per microcosm in 3 weeks. iron and molybdenum levels in plants were strongly associated with N fixation, and N uptake from media was estimated to be more than 25 mg per microcosm in 3 weeks, indicating that A. japonica has N remediation potential. As A. japonica is a rapidly growing plant, capable of efficient P and N remediation, it has great potential for use in phytoremediation of nutrient-enriched waters such as agricultural or urban wastewater and eutrophicated aquatic ecosystems.

  2. Physical barriers formed from gelling liquids: 1. numerical design of laboratory and field experiments

    International Nuclear Information System (INIS)

    Finsterle, S.; Moridis, G.J.; Pruess, K.; Persoff, P.

    1994-01-01

    The emplacement of liquids under controlled viscosity conditions is investigated by means of numerical simulations. Design calculations are performed for a laboratory experiment on a decimeter scale, and a field experiment on a meter scale. The purpose of the laboratory experiment is to study the behavior of multiple gout plumes when injected in a porous medium. The calculations for the field trial aim at designing a grout injection test from a vertical well in order to create a grout plume of a significant extent in the subsurface

  3. 3D mapping of turbulence: a laboratory experiment

    Science.gov (United States)

    Le Louarn, Miska; Dainty, Christopher; Paterson, Carl; Tallon, Michel

    2000-07-01

    In this paper, we present the first experimental results of the 3D mapping method. 3D mapping of turbulence is a method to remove the cone effect with multiple laser guide stars and multiple deformable mirrors. A laboratory experiment was realized to verify the theoretical predictions. The setup consisted of two turbulent phase screens (made with liquid crystal devices) and a Shack-Hartmann wavefront sensor. We describe the interaction matrix involved in reconstructing Zernike commands for multiple deformable mirror from the slope measurements made from laser guide stars. It is shown that mirror commands can indeed be reconstructed with the 3D mapping method. Limiting factors of the method, brought to light by this experiment are discussed.

  4. Large aperture harmonic conversion experiments at Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Linford, G.J.; Johnson, B.C.; Hildum, J.S.; G. J. Linford is now with Max-Planck-Institut fur Quantenoptik, D-8046 Garching, Federal Republic of Germany)

    1982-01-01

    Large aperture harmonic conversion experiments to 2ω (532 nm), 3ω (355 nm), and 4ω (266 nm) on the Argus laser at the Livermore National Laboratory are described. Harmonically converted energies of up to 346 J have been generated at external conversion efficiencies of 83%. A discussion of the harmonic conversion experiments and a brief summary of enhanced 2ω and 3ω inertial confinement fusion target performances are provided

  5. Large aperture harmonic conversion experiments at Lawrence Livermore National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Linford, G.J.; Johnson, B.C.; Hildum, J.S.; Martin, W.E.; Snyder, K.; Boyd, R.D.; Smith, W.L.; Vercimak, C.L.; Eimerle, D.; Hunt, J.T.

    1982-10-15

    Large aperture harmonic conversion experiments to 2..omega.. (532 nm), 3..omega.. (355 nm), and 4..omega.. (266 nm) on the Argus laser at the Livermore National Laboratory are described. Harmonically converted energies of up to 346 J have been generated at external conversion efficiencies of 83%. A discussion of the harmonic conversion experiments and a brief summary of enhanced 2..omega.. and 3..omega.. inertial confinement fusion target performances are provided.

  6. Fate and persistence of a pathogenic NDM-1-positive Escherichia coli strain in anaerobic and aerobic sludge microcosms

    KAUST Repository

    Mantilla-Calderon, David

    2017-04-15

    The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly slower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable but no further decay was observed. Instead, 1 in every 10000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 were detected to have transferred to other native microorganisms in the sludge, or are released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24 h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater.IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study points at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic

  7. Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms.

    Science.gov (United States)

    Mantilla-Calderon, David; Hong, Pei-Ying

    2017-07-01

    The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the

  8. On the potential for using immersive virtual environments to support laboratory experiment contextualisation

    Science.gov (United States)

    Machet, Tania; Lowe, David; Gütl, Christian

    2012-12-01

    This paper explores the hypothesis that embedding a laboratory activity into a virtual environment can provide a richer experimental context and hence improve the understanding of the relationship between a theoretical model and the real world, particularly in terms of the model's strengths and weaknesses. While an identified learning objective of laboratories is to support the understanding of the relationship between models and reality, the paper illustrates that this understanding is hindered by inherently limited experiments and that there is scope for improvement. Despite the contextualisation of learning activities having been shown to support learning objectives in many fields, there is traditionally little contextual information presented during laboratory experimentation. The paper argues that the enhancing laboratory activity with contextual information affords an opportunity to improve students' understanding of the relationship between the theoretical model and the experiment (which is effectively a proxy for the complex real world), thereby improving their understanding of the relationship between the model and reality. The authors propose that these improvements can be achieved by setting remote laboratories within context-rich virtual worlds.

  9. Effects of a mixture of tetracyclines to Lemna gibba and Myriophyllum sibiricum evaluated in aquatic microcosms

    Energy Technology Data Exchange (ETDEWEB)

    Brain, Richard A [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Wilson, Christian J [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Johnson, David J [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Sanderson, Hans [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Bestari, Ketut [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Hanson, Mark L [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Sibley, Paul K [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Solomon, Keith R [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada)

    2005-12-15

    The impact of a mixture of oxytetracycline, chlortetracycline, tetracycline and doxycycline on Myriophyllum sibiricum and Lemna gibba was investigated using fifteen 12,000-L microcosms (k = 5, n = 3). Significant concentration-response relationships were only found for M. sibiricum, where dry mass was 69, 47, 30, and 7% of controls at respective treatment concentrations of 0.080, 0.218, 0.668, and 2.289 {mu}mol/L. Somatic endpoints were strongly and negatively correlated with percent light transmission, except plant length, which was positively correlated. Treated microcosms experienced a reduction in the percent of surface irradiance penetrating the water column as high as 99.8% at a depth of 70 cm, relative to controls. Position relative to the water column was likely responsible for the differential effects observed between floating (L. gibba) and submerged (M. sibiricum) species of macrophytes. A hazard quotient assessment of the lowest EC{sub 10} value indicated significant risk, exceeding the critical HQ value, but not the lowest EC{sub 25} value. - Mixtures of tetracycline antibiotics pose a risk to submerged but not floating aquatic plants.

  10. Effects of a mixture of tetracyclines to Lemna gibba and Myriophyllum sibiricum evaluated in aquatic microcosms

    International Nuclear Information System (INIS)

    Brain, Richard A.; Wilson, Christian J.; Johnson, David J.; Sanderson, Hans; Bestari, Ketut; Hanson, Mark L.; Sibley, Paul K.; Solomon, Keith R.

    2005-01-01

    The impact of a mixture of oxytetracycline, chlortetracycline, tetracycline and doxycycline on Myriophyllum sibiricum and Lemna gibba was investigated using fifteen 12,000-L microcosms (k = 5, n = 3). Significant concentration-response relationships were only found for M. sibiricum, where dry mass was 69, 47, 30, and 7% of controls at respective treatment concentrations of 0.080, 0.218, 0.668, and 2.289 μmol/L. Somatic endpoints were strongly and negatively correlated with percent light transmission, except plant length, which was positively correlated. Treated microcosms experienced a reduction in the percent of surface irradiance penetrating the water column as high as 99.8% at a depth of 70 cm, relative to controls. Position relative to the water column was likely responsible for the differential effects observed between floating (L. gibba) and submerged (M. sibiricum) species of macrophytes. A hazard quotient assessment of the lowest EC 10 value indicated significant risk, exceeding the critical HQ value, but not the lowest EC 25 value. - Mixtures of tetracycline antibiotics pose a risk to submerged but not floating aquatic plants

  11. The use of terrestrial and aquatic microcosms and mesocosms for the ecological risk assessment of veterinary medicinal products

    NARCIS (Netherlands)

    Brink, van den P.J.; Tarzona, J.V.; Solomon, K.R.; Knacker, T.; Brink, van den N.W.; Brock, T.C.M.; Hoogland, J.P.

    2005-01-01

    In this paper, we investigate the applicability of experimental model ecosystems (microcosms and mesocosms) for the ecological risk assessment of veterinary medicinal products (VMPs). VMPs are used in large quantities, but the assessment of associated risks to the environment is limited, although

  12. Closing the loop on improvement: Packaging experience in the Software Engineering Laboratory

    Science.gov (United States)

    Waligora, Sharon R.; Landis, Linda C.; Doland, Jerry T.

    1994-01-01

    As part of its award-winning software process improvement program, the Software Engineering Laboratory (SEL) has developed an effective method for packaging organizational best practices based on real project experience into useful handbooks and training courses. This paper shares the SEL's experience over the past 12 years creating and updating software process handbooks and training courses. It provides cost models and guidelines for successful experience packaging derived from SEL experience.

  13. Chlorodifluoroacetic acid fate and toxicity to the macrophytes Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum in aquatic microcosms.

    Science.gov (United States)

    Hanson, M L; Sibley, P K; Mabury, S A; Muir, D C; Solomon, K R

    2001-12-01

    Chlorodifluoroacetic acid (CDFA) is a novel haloacetic acid (HAA) and has been recently documented in aquatic systems. It is a suspected degradation product of the refrigerants 1,1,2-trichloro-1,1-difluoroethane (CFC-113) and 1-chloro-1,1-difluoroethane (HCFC-142b). Haloacetic acids can be phytotoxic, putatively acting through inhibition of the citric acid cycle. Replicate (n = 3) 12,000-L model aquatic ecosystems (microcosms) were dosed once at 0.5, 1, 5, and 20 mg/L of neutralized CDFA. Three microcosms served as controls. Each microcosm was stocked with eight individual apical shoots of both Myriophyllum spicatum and Myriophyllum sibiricum and sampled at regular intervals over a 42-d exposure period. The plants were assessed for the somatic endpoints of plant length, root growth, node number, and wet and dry mass and the biochemical endpoints of chlorophyll-a/b and carotenoid content as well as citric acid levels. The duckweed Lemna gibba was also introduced into these systems and monitored over a period of 14 d for wet/dry mass, plant/frond number, chlorophyll content, and growth rate. Concentrations of CDFA remained constant in the water column over the course of the fate investigation (241 d), indicating that this compound undergoes little, if any, degradation in aquatic systems. Results showed few statistically significant differences from controls for all three plant species with exposure to CDFA but no biologically relevant impacts. Overall, CDFA does not appear to pose any risk to these aquatic macrophytes at current environmental concentrations.

  14. Book Review "Advances on remote laboratories and e-learning experiences"

    Directory of Open Access Journals (Sweden)

    Jesús A. del Alamo

    2007-08-01

    Full Text Available Book Review "Advances on remote laboratories and e-learning experiences", book editors: Luís Gomes and Javier García-Zubía, University of Deusto, Spain. Reviewed by Jesús A. del Alamo, Massachusetts Institute of Technology, M.I.T.

  15. Evaluation of community structure and community function after exposure to the turbine fuel jet-A

    International Nuclear Information System (INIS)

    Rodgers, S.C.; Landis, W.G.

    1993-01-01

    The underlying premises of the Mixed Flask Culture (MFC), an aquatic microcosm design, include (1) that the effects of a perturbation to an aquatic community may be monitored through the measurement of its functional parameters (i.e. pH and productivity/respiration ratio) and (2) these measurements will be similar between different wild-derived communities given the same perturbation. Two MFC experiments were conducted to assess these two premises. The treatment groups in both experiments consisted of 0%, 1%, 5%, and 15% WSF Jet-A with six replicates respectively. The experimental designs reflected both the MFC and the Standard Aquatic Microcosm (SAM); this hybrid design resulted in following a MFC protocol, but incorporated the SAM specified laboratory cultured organisms. Beaker homogeneity via cross inoculation and reinoculation was encouraged in the first experiment prior to dosing. Beaker heterogeneity was encouraged in the first experiment prior to dosing. Beaker heterogeneity was encouraged in the second experiment by not cross inoculating or reinoculating. The differences between the two experiments was designed to indicate if differently derived communities react similarly to an identical perturbation. Do the microcosms within each treatment group resemble each other functionally throughout the experiment, or is the within group deviation greater than the between group deviation?

  16. Influence of Aroclor 1242 Concentration on Polychlorinated Biphenyl Biotransformations in Hudson River Test Tube Microcosms

    Science.gov (United States)

    Fish, K. M.

    1996-01-01

    When 93.3 to 933 (mu)mol of Aroclor 1242 per kg was added to Hudson River sediment test tube microcosms, the rates of polychlorinated biphenyl biotransformations increased with increasing Aroclor 1242 concentration after a 4- to 8-week acclimation period. In contrast, when 37.3 (mu)mol of Aroclor 1242 per kg was added, polychlorinated biphenyl biotransformations occurred at slow constant rates. PMID:16535387

  17. Real-time laboratory exercises to test contingency plans for classical swine fever: experiences from two national laboratories.

    Science.gov (United States)

    Koenen, F; Uttenthal, A; Meindl-Böhmer, A

    2007-12-01

    In order to adequately and efficiently handle outbreaks of contagious diseases such as classical swine fever (CSF), foot and mouth disease or highly pathogenic avian influenza, competent authorities and the laboratories involved have to be well prepared and must be in possession of functioning contingency plans. These plans should ensure that in the event of an outbreak access to facilities, equipment, resources, trained personnel, and all other facilities needed for the rapid and efficient eradication of the outbreak is guaranteed, and that the procedures to follow are well rehearsed. It is essential that these plans are established during 'peace-time' and are reviewed regularly. This paper provides suggestions on how to perform laboratory exercises to test preparedness and describes the experiences of two national reference laboratories for CSF. The major lesson learnt was the importance of a well-documented laboratory contingency plan. The major pitfalls encountered were shortage of space, difficulties in guaranteeing biosecurity and sufficient supplies of sterile equipment and consumables. The need for a standardised laboratory information management system, that is used by all those involved in order to reduce the administrative load, is also discussed.

  18. Enhanced biodegradation of naphthalene in MGP aquifer microcosms

    International Nuclear Information System (INIS)

    Durant, N.D.; Jonkers, C.A.A.; Wilson, L.P.; Bouwer, E.J.

    1995-01-01

    Subsurface sediments collected from a former manufactured-gas-plant (MGP) site contain bacteria capable of mineralizing significant amounts of 14 C-naphthalene in aerobic (8.5 mg/L O 2 ) sediment-water microcosms incubated at 10 C. The extent to which electron-acceptor (O 2 and NO 3 - ) and nutrient (NO 3 - and PO 4 3- ) amendments enhanced naphthalene mineralization in these sediments varied considerably. Oxygen-amended conditions (21 mg/L O 2 ) resulted in the greatest rate and extent of biodegradation for most sediments. Data suggested, however, that some MGP-site sediments prefer mixed NO 3 - /O 2 electron-acceptor conditions for naphthalene biodegradation. Significant denitrification was observed in the nitrate-amended sediments exhibiting naphthalene mineralization. In most cases, PO 4 3- complexed with the sediments either had no effect or inhibited naphthalene mineralization. Sediments unable to mineralize naphthalene over the 6-week incubation period were characterized by low pH ( 4 2- (>500 mg/L) conditions

  19. Maintenance experiences at analytical laboratory at the Tokai reprocessing plant

    International Nuclear Information System (INIS)

    Suzuki, Hisanori; Nagayama, Tetsuya; Horigome, Kazushi; Ishibashi, Atsushi; Kitao, Takahiko; Surugaya, Naoki

    2014-01-01

    The Tokai Reprocessing Plant (TRP) is developing the technology to recover uranium and plutonium from spent nuclear fuel. There is an analytical laboratory which was built in 1977, as one of the most important facilities for process and material control analyses at the TRP. Samples taken from each process are analyzed by various analytical methods using hot cells, glove boxes and hume-hoods. A large number of maintenance work have been so far carried out and different types of experience have been accumulated. This paper describes our achievements in the maintenance activities at the analytical laboratory at the TRP. (author)

  20. Swedish-German actinide migration experiment at ÄSPÖ hard rock laboratory

    Science.gov (United States)

    Kienzler, B.; Vejmelka, P.; Römer, J.; Fanghänel, E.; Jansson, M.; Eriksen, T. E.; Wikberg, P.

    2003-03-01

    Within the scope of a bilateral cooperation between Svensk Kärnbränslehantering (SKB) and Forschungszentrum Karlsruhe, Institut für Nukleare Entsorgung (FZK-INE), an actinide migration experiment is currently being performed at the Äspö Hard Rock Laboratory (HRL) in Sweden. This paper covers laboratory and in situ investigations on actinide migration in single-fractured granite core samples. For the in situ experiment, the CHEMLAB 2 probe developed by SKB was used. The experimental setup as well as the breakthrough of inert tracers and of the actinides Am, Np and Pu are presented. The breakthrough curves of inert tracers were analyzed to determine hydraulic properties of the fractured samples. Postmortem analyses of the solid samples were performed to characterize the flow path and the sorbed actinides. After cutting the cores, the abraded material was analyzed with respect to sorbed actinides. The slices were scanned optically to visualize the flow path. Effective volumes and inner surface areas were measured. In the experiments, only breakthrough of Np(V) was observed. In each experiment, the recovery of Np(V) was ≤40%. Breakthrough of Am(III) and Pu(IV) as well as of Np(IV) was not observed.

  1. Aerobic degradation potential of the herbicides mecoprop, dichlorprop and bentazone in groundwater from chalk aquifers

    DEFF Research Database (Denmark)

    Levi, Suzi; Hybel, Anne-Marie; Bjerg, Poul Løgstrup

    2011-01-01

    The aerobic degradation potential of mecoprop, dichlorprop and bentazone was studied at concentration of 1 μg/L in laboratory batch experiments with groundwater from chalk aquifers. Within the incubation period of 129 days, 14C-mecoprop concentration decreased to 60-80% in the microcosms with gro...

  2. Zero-Gravity Atmospheric Cloud Physics Experiment Laboratory engineering concepts/design tradeoffs. Volume 1: Study results

    Science.gov (United States)

    Greco, R. V.; Eaton, L. R.; Wilkinson, H. C.

    1974-01-01

    The work is summarized which was accomplished from January 1974 to October 1974 for the Zero-Gravity Atmospheric Cloud Physics Laboratory. The definition and development of an atmospheric cloud physics laboratory and the selection and delineation of candidate experiments that require the unique environment of zero gravity or near zero gravity are reported. The experiment program and the laboratory concept for a Spacelab payload to perform cloud microphysics research are defined. This multimission laboratory is planned to be available to the entire scientific community to utilize in furthering the basic understanding of cloud microphysical processes and phenomenon, thereby contributing to improved weather prediction and ultimately to provide beneficial weather control and modification.

  3. BOW SHOCK FRAGMENTATION DRIVEN BY A THERMAL INSTABILITY IN LABORATORY ASTROPHYSICS EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki-Vidal, F.; Lebedev, S. V.; Pickworth, L. A.; Swadling, G. F.; Skidmore, J.; Hall, G. N.; Bennett, M.; Bland, S. N.; Burdiak, G.; De Grouchy, P.; Music, J.; Suttle, L. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Ciardi, A. [Sorbonne Universités, UPMC Univ. Paris 6, UMR 8112, LERMA, F-75005, Paris (France); Rodriguez, R.; Gil, J. M.; Espinosa, G. [Departamento de Fisica de la Universidad de Las Palmas de Gran Canaria, E-35017 Las Palmas de Gran Canaria (Spain); Hartigan, P. [Department of Physics and Astronomy, Rice University, 6100 S. Main, Houston, TX 77521-1892 (United States); Hansen, E.; Frank, A., E-mail: f.suzuki@imperial.ac.uk [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)

    2015-12-20

    The role of radiative cooling during the evolution of a bow shock was studied in laboratory-astrophysics experiments that are scalable to bow shocks present in jets from young stellar objects. The laboratory bow shock is formed during the collision of two counterstreaming, supersonic plasma jets produced by an opposing pair of radial foil Z-pinches driven by the current pulse from the MAGPIE pulsed-power generator. The jets have different flow velocities in the laboratory frame, and the experiments are driven over many times the characteristic cooling timescale. The initially smooth bow shock rapidly develops small-scale nonuniformities over temporal and spatial scales that are consistent with a thermal instability triggered by strong radiative cooling in the shock. The growth of these perturbations eventually results in a global fragmentation of the bow shock front. The formation of a thermal instability is supported by analysis of the plasma cooling function calculated for the experimental conditions with the radiative packages ABAKO/RAPCAL.

  4. Eight year experience in open ended instrumentation laboratory

    Science.gov (United States)

    Marques, Manuel B.; Rosa, Carla C.; Marques, Paulo V. S.

    2015-10-01

    When designing laboratory courses in a Physics Major we consider a range of objectives: teaching Physics; developing lab competencies; instrument control and data acquisition; learning about measurement errors and error propagation; an introduction to project management; team work skills and scientific writing. But nowadays we face pressure to decrease laboratory hours due to the cost involved. Many universities are replacing lab classes for simulation activities, hiring PhD. and master students to give first year lab classes, and reducing lab hours. This leads to formatted lab scripts and poor autonomy of the students, and failure to enhance creativity and autonomy. In this paper we present our eight year experience with a laboratory course that is mandatory in the third year of Physics and Physical Engineering degrees. Since the students had previously two standard laboratory courses, we focused on teaching instrumentation and giving students autonomy. The course is divided in two parts: one third is dedicated to learn computer controlled instrumentation and data acquisition (based in LabView); the final 2/3 is dedicated to a group project. In this project, the team (2 or 3 students) must develop a project and present it in a typical conference format at the end of the semester. The project assignments are usually not very detailed (about two or three lines long), giving only general guidelines pointing to a successful project (students often recycle objectives putting forward a very personal project); all of them require assembling some hardware. Due to our background, about one third of the projects are related to Optics.

  5. The safeguards on-site laboratory at Sellafield. Five years operational experience

    Energy Technology Data Exchange (ETDEWEB)

    Duinslaeger, L.; Belle, P. van; Mayer, K.; Casteleyn, K.; Abousahl, S.; Daures, P.; Eberle, H.; Enright, T.; Guiot, A.; Hild, M.; Horta Domenech, J.; Lajarge, P.; Laurent, P.; Le Terrier, A.; Lynch, B.; Marucci, M.; Millet, S.; Ottmar, H.; Richir, P.; Street, S.; Vallet, P.; Zuleger, E. [European Commission, Karlsruhe (Germany). Inst. for Transuranium Elements

    2004-06-01

    The start of operation of the large reprocessing facilities led Euratom Safeguards to a new approach for verification analysis of samples taken at the facility: the installation of on-site laboratories. The availability of analytical capabilities for independent verification measurements at the site of these facilities offers obvious advantages in view of timeliness of results. The 'On-Site Laboratory' (OSL) at the BNFL Sellafield site was the first ever and entered into operation in 1999. For almost five years, the Institute for Transuranium Elements (ITU) has been operating the laboratory under routine conditions. During this period, more than one thousand safeguards samples were analysed. The experience gained in the management, logistics and operation of the OSL allow a critical review based on a significant period in time. This includes also aspects of training of staff, maintenance of equipment, flow of information, and improvements in the efficiency. The analytical issues are of key importance: based on the operational experience, the measurement methods were adapted (changing boundary conditions), the distribution of samples according to material type changed (start up of MOS fabrication plant), and the cutback in resources triggered a further streamlining of the analytical efforts. (orig.)

  6. Cleanup of a Department of Energy Nonreactor Nuclear Facility: Experience at the Los Alamos National Laboratory High Pressure Tritium Laboratory

    International Nuclear Information System (INIS)

    Horak, H.L.

    1995-01-01

    On October 25, 1990, Los Alamos National Laboratory (LANL) ceased programmatic operations at the High Pressure Tritium Laboratory (HPTL). Since that time, LANL has been preparing the facility for transfer into the Department of Energy's (DOE's) Decontamination and Decommissioning Program. LANL staff now has considerable operational experience with the cleanup of a 40-year-old facility used exclusively to conduct experiments in the use of tritium, the radioactive isotope of hydrogen. Tritium and its compounds have permeated the HPTL structure and equipment, have affected operations and procedures, and now dominate efforts at cleanup and disposal. At the time of shutdown, the HPTL still had a tritium inventory of over 100 grams in a variety of forms and containers

  7. Monitoring Arthrobacter protophormiae RKJ100 in a 'tag and chase' method during p-nitrophenol bio-remediation in soil microcosms.

    Science.gov (United States)

    Pandey, Gunjan; Pandey, Janmejay; Jain, Rakesh K

    2006-05-01

    Monitoring of micro-organisms released deliberately into the environment is essential to assess their movement during the bio-remediation process. During the last few years, DNA-based genetic methods have emerged as the preferred method for such monitoring; however, their use is restricted in cases where organisms used for bio-remediation are not well characterized or where the public domain databases do not provide sufficient information regarding their sequence. For monitoring of such micro-organisms, alternate approaches have to be undertaken. In this study, we have specifically monitored a p-nitrophenol (PNP)-degrading organism, Arthrobacter protophormiae RKJ100, using molecular methods during PNP degradation in soil microcosm. Cells were tagged with a transposon-based foreign DNA sequence prior to their introduction into PNP-contaminated microcosms. Later, this artificially introduced DNA sequence was PCR-amplified to distinguish the bio-augmented organism from the indigenous microflora during PNP bio-remediation.

  8. Transport and degradation of pesticides in a biopurification system under variable flux, part I: A microcosm study

    Energy Technology Data Exchange (ETDEWEB)

    De Wilde, Tineke, E-mail: dewilde.tineke@gmail.co [Laboratory of Crop Protection Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Spanoghe, Pieter [Laboratory of Crop Protection Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Ryckeboer, Jaak [Division Soil and Water Management, Faculty of Bioscience Engineering, Catholic University Leuven, Kasteelpark Arenberg 20, B-3001 Leuven (Belgium); Jaeken, Peter [PCF-Royal Research Station of Gorsem, De Brede Akker 13, 3800 Sint-Truiden (Belgium); Springael, Dirk [Division Soil and Water Management, Faculty of Bioscience Engineering, Catholic University Leuven, Kasteelpark Arenberg 20, B-3001 Leuven (Belgium)

    2010-10-15

    The efficiency of a biopurification system, developed to treat pesticide contaminated water, is to a large extent determined by the chemical and hydraulic load. Insight into the behaviour of pesticides under different fluxes is necessary. The behaviour of metalaxyl, bentazone, linuron, isoproturon and metamitron was studied under three different fluxes with or without the presence of pesticide-primed soil in column experiments. Due to the time-dependent sorption process, retention of the pesticides with intermediate mobility was significantly influenced by the flux. The higher the flux, the slower pesticides will be sorbed, which resulted in a lower retention. Degradation of the intermediate mobile pesticides was also submissive to variations in flux. An increase in flux, led to a decrease in retention, which in turn decreased the opportunity time for biodegradation. Finally, the presence of pesticide-primed soil was only beneficial for the degradation of metalaxyl. - Retention and degradation of pesticides in microcosms liable to different fluxes.

  9. Lecture Meets Laboratory - Experimental Experiences for Large Audiences: Concept and Implementation

    Directory of Open Access Journals (Sweden)

    Katrin Temmen

    2014-10-01

    Full Text Available Lecture courses are an integral part of academia with a long tradition. The efficiency of such courses can be notably increased by active participation of students in the learning process. This article will elaborate on a re-structuring of an engineering lecture attended by more than 400 students; during the course, laboratory experiments are integrated directly into the lecture, allowing students to gain their own practical experience.

  10. Georgia Teachers in Academic Laboratories: Research Experiences in the Geosciences

    Science.gov (United States)

    Barrett, D.

    2005-12-01

    The Georgia Intern-Fellowships for Teachers (GIFT) is a collaborative effort designed to enhance mathematics and science experiences of Georgia teachers and their students through summer research internships for teachers. By offering business, industry, public science institute and research summer fellowships to teachers, GIFT provides educators with first-hand exposure to the skills and knowledge necessary for the preparation of our future workforce. Since 1991, GIFT has placed middle and high school mathematics, science and technology teachers in over 1000 positions throughout the state. In these fellowships, teachers are involved in cutting edge scientific and engineering research, data analysis, curriculum development and real-world inquiry and problem solving, and create Action Plans to assist them in translating the experience into changed classroom practice. Since 2004, an increasing number of high school students have worked with their teachers in research laboratories. The GIFT program places an average of 75 teachers per summer into internship positions. In the summer of 2005, 83 teachers worked in corporate and research environments throughout the state of Georgia and six of these positions involved authentic research in geoscience related departments at the Georgia Institute of Technology, including aerospace engineering and the earth and atmospheric sciences laboratories. This presentation will review the history and the structure of the program including the support system for teachers and mentors as well as the emphasis on inquiry based learning strategies. The focus of the presentation will be a comparison of two placement models of the teachers placed in geoscience research laboratories: middle school earth science teachers placed in a 6 week research experience and high school teachers placed in 7 week internships with teams of 3 high school students. The presentation will include interviews with faculty to determine the value of these experiences

  11. Laboratory experiments in innovation research: A methodological overview and a review of the current literature

    OpenAIRE

    Brüggemann, Julia; Bizer, Kilian

    2016-01-01

    Innovation research has developed a broad set of methodological approaches in recent decades. In this paper, we propose laboratory experiments as a fruitful methodological addition to the existing methods in innovation research. Therefore, we provide an overview of the existing methods, discuss the advantages and limitations of laboratory experiments, and review experimental studies dealing with different fields of innovation policy, namely intellectual property rights, financi...

  12. Ecological effects of spring and late summer applications of lambda-cyhalothrin on freshwater microcosms.

    Science.gov (United States)

    Van Wijngaarden, R P A; Brock, T C M; van den Brink, P J; Gylstra, R; Maund, S J

    2006-02-01

    The aim of the study was to compare the effects of the pyrethroid insecticide lambda-cyhalothrin (treated at 10, 25, 50, 100, 250 ng active ingredient a.i./L) on a drainage ditch ecosystem in spring and late summer. Microcosms (water volume approximately 430 L) were established using enclosures in a 50-cm-deep experimental ditch system containing communities typical of macrophyte-dominated freshwater ecosystems. Effects on macroinvertebrates, zooplankton, phytoplankton, macrophytes, and community metabolism were assessed and evaluated using univariate and multivariate statistical techniques. The macroinvertebrate community responded most clearly to treatment and, as anticipated, insects and crustaceans were among the most sensitive organisms. Statistical analysis showed that the underlying community structure was significantly different between the spring and summer experiments. However, the most sensitive species (Chaoborus obscuripes and Gammarus pulex) were abundant in spring as well as in late summer. In spring and late summer, only slight and transient effects were observed at the community level in the 10-ng/L treatment. Overall, the study did not show substantial differences in the responses of sensitive taxa between spring and late summer treatments, and effects thresholds were similar irrespective of season of treatment.

  13. An Experiment Using Sucrose Density Gradients in the Undergraduate Biochemistry Laboratory.

    Science.gov (United States)

    Turchi, Sandra L.; Weiss, Monica

    1988-01-01

    Describes an experiment to be performed in an undergraduate biochemistry laboratory that is based on a gradient centrifugation system employing a simple bench top centrifuge, a freezer, and frozen surcose gradient solution to separate macromolecules and subcellular components. (CW)

  14. Petroleum-hydrocarbon utilization by native bacterial population ...

    African Journals Online (AJOL)

    Two Nigerian crude oils (Bonny light and Escravos blend) were exposed to the wastewater canal via oil impregnated membrane filters (0.45 μm diameter) for 21 days in a microcosm experiment. Bacterial petroleum-hydrocarbon utilizers were later harvested from both the millipore membrane filters and laboratory ...

  15. Development and Use of Online Prelaboratory Activities in Organic Chemistry to Improve Students' Laboratory Experience

    Science.gov (United States)

    Chaytor, Jennifer L.; Al Mughalaq, Mohammad; Butler, Hailee

    2017-01-01

    Online prelaboratory videos and quizzes were prepared for all experiments in CHEM 231, Organic Chemistry I Laboratory. It was anticipated that watching the videos would help students be better prepared for the laboratory, decrease their anxiety surrounding the laboratory, and increase their understanding of the theories and concepts presented.…

  16. Visual Representations of Microcosm in Textbooks of Chemistry: Constructing a Systemic Network for Their Main Conceptual Framework

    Science.gov (United States)

    Papageorgiou, George; Amariotakis, Vasilios; Spiliotopoulou, Vasiliki

    2017-01-01

    The main objective of this work is to analyse the visual representations (VRs) of the microcosm depicted in nine Greek secondary chemistry school textbooks of the last three decades in order to construct a systemic network for their main conceptual framework and to evaluate the contribution of each one of the resulting categories to the network.…

  17. Transfer of elements relevant to nuclear fuel cycle from soil to boreal plants and animals in experimental meso- and microcosms

    Energy Technology Data Exchange (ETDEWEB)

    Tuovinen, Tiina S., E-mail: tiina.tuovinen@uef.fi [Department of Environmental Science, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio (Finland); Kasurinen, Anne; Häikiö, Elina [Department of Environmental Science, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio (Finland); Tervahauta, Arja [Department of Biology, University of Eastern Finland, P.O. Box FI-70211, Kuopio (Finland); Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka [Department of Environmental Science, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio (Finland)

    2016-01-01

    Uranium (U), cobalt (Co), molybdenum (Mo), nickel (Ni), lead (Pb), thorium (Th) and zinc (Zn) occur naturally in soil but their radioactive isotopes can also be released into the environment during the nuclear fuel cycle. The transfer of these elements was studied in three different trophic levels in experimental mesocosms containing downy birch (Betula pubescens), narrow buckler fern (Dryopteris carthusiana) and Scandinavian small-reed (Calamagrostis purpurea ssp. Phragmitoides) as producers, snails (Arianta arbostorum) as herbivores, and earthworms (Lumbricus terrestris) as decomposers. To determine more precisely whether the element uptake of snails is mainly via their food (birch leaves) or both via soil and food, a separate microcosm experiment was also performed. The element uptake of snails did not generally depend on the presence of soil, indicating that the main uptake route was food, except for U, where soil contact was important for uptake when soil U concentration was high. Transfer of elements from soil to plants was not linear, i.e. it was not correctly described by constant concentration ratios (CR) commonly applied in radioecological modeling. Similar nonlinear transfer was found for the invertebrate animals included in this study: elements other than U were taken up more efficiently when element concentration in soil or food was low. - Highlights: • We studied transfer of elements in boreal food chain using meso- and microcosms. • Elements related to nuclear fuel cycle and mining were examined. • Higher uptake at lower soil concentrations was observed for primary producers. • Snails took up elements mainly from food but for U also soil was an element source. • Non-linear transfer of essential elements was observed for herbivore and decomposer.

  18. Fate of N-nitrosodimethylamine in recycled water after recharge into anaerobic aquifer.

    Science.gov (United States)

    Patterson, B M; Pitoi, M M; Furness, A J; Bastow, T P; McKinley, A J

    2012-03-15

    Laboratory and field experiments were undertaken to assess the fate of N-nitrosodimethylamine (NDMA) in aerobic recycled water that was recharged into a deep anaerobic pyritic aquifer, as part of a managed aquifer recharge (MAR) strategy. Laboratory studies demonstrated a high mobility of NDMA in the Leederville aquifer system with a retardation coefficient of 1.1. Anaerobic degradation column and (14)C-NDMA microcosm studies showed that anaerobic conditions of the aquifer provided a suitable environment for the biodegradation of NDMA with first-order kinetics. At microgram per litre concentrations, inhibition of biodegradation was observed with degradation half-lives (260±20 days) up to an order of magnitude greater than at nanogram per litre concentrations (25-150 days), which are more typical of environmental concentrations. No threshold effects were observed at the lower ng L(-1) concentrations with NDMA concentrations reduced from 560 ng L(-1) to recharge bore. These microcosm experiments showed a faster degradation rate than anaerobic microcosms, with a degradation half-life of 8±2 days, after a lag period of approximately 10 days. Results from a MAR field trial recharging the Leederville aquifer with aerobic recycled water showed that NDMA concentrations reduced from 2.5±1.0 ng L(-1) to 1.3±0.4 ng L(-1) between the recharge bore and a monitoring location 20 m down gradient (an estimated aquifer residence time of 10 days), consistent with data from the aerobic microcosm experiment. Further down gradient, in the anaerobic zone of the aquifer, NDMA degradation could not be assessed, as NDMA concentrations were too close to their analytical detection limit (<1 ng L(-1)). Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  19. Sampling Participants' Experience in Laboratory Experiments: Complementary challenges for more complete data collection

    Directory of Open Access Journals (Sweden)

    Alan eMcAuliffe

    2016-05-01

    Full Text Available Speelman and McGann's (2013 examination of the uncritical way in which the mean is often used in psychological research raises questions both about the average's reliability and its validity. In the present paper, we argue that interrogating the validity of the mean involves, amongst other things, a better understanding of the person's experiences, the meaning of their actions, at the time that the behaviour of interest is carried out. Recently emerging approaches within Psychology and Cognitive Science have argued strongly that experience should play a more central role in our examination of behavioural data, but the relationship between experience and behaviour remains very poorly understood. We outline some of the history of the science on this fraught relationship, as well as arguing that contemporary methods for studying experience fall into one of two categories. Wide approaches tend to incorporate naturalistic behaviour settings, but sacrifice accuracy and reliability in behavioural measurement. Narrow approaches maintain controlled measurement of behaviour, but involve too specific a sampling of experience, which obscures crucial temporal characteristics. We therefore argue for a novel, mid-range sampling technique, that extends Hurlburt's Descriptive Experience Sampling, and adapts it for the controlled setting of the laboratory. This Controlled Descriptive Experience Sampling may be an appropriate tool to help calibrate both the mean and the meaning of an experimental situation with one another.

  20. Artificial Crab Burrows Facilitate Desalting of Rooted Mangrove Sediment in a Microcosm Study

    Directory of Open Access Journals (Sweden)

    Nathalie Pülmanns

    2015-07-01

    Full Text Available Water uptake by mangrove trees can result in salt accumulation in sediment around roots, negatively influencing growth. Tidal pumping facilitates salt release and can be enhanced by crab burrows. Similarly, flushing of burrows by incoming tidal water decreases sediment salinity. In contrast to burrows with multiple entrances, the role of burrows with one opening for salinity reduction is largely unknown. In a microcosm experiment we studied the effect of artificial, burrow-like macro-pores with one opening on the desalting of mangrove sediment and growth of Rhizophora mangle L. seedlings. Sediment salinity, seedling leaf area and seedling growth were monitored over six months. Artificial burrows facilitated salt release from the sediment after six weeks, but seedling growth was not influenced. To test whether crab burrows with one opening facilitate salt release in mangrove forests, sediment salinities were measured in areas with and without R. mangle stilt roots in North Brazil at the beginning and end of the wet season. In addition, burrows of Ucides cordatus were counted. High crab burrow densities and sediment salinities were associated with stilt root occurrence. Precipitation and salt accumulation by tree roots seem to have a larger effect on sediment salinity than desalting by U. cordatus burrows.

  1. Effect of tetracycline residues in pig manure slurry on tetracycline-resistant bacteria and resistance gene tet(M) in soil microcosms

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Wulff, Gitte; Vaclavik, Elvira

    2006-01-01

    and oxytetracycline were almost stable through out the experimental period, but the tetracycline concentrations had no effect on prevalence of tetracycline-resistant bacteria. The presented microcosm approach simulated natural farmland conditions well and supported results from previous field studies. (c) 2006...

  2. Laboratory Experiment Investigating the Impact of Ocean Acidification on Calcareous Organisms

    Science.gov (United States)

    Perera, Alokya P.; Bopegedera, A. M. R. P.

    2014-01-01

    The increase in ocean acidity since preindustrial times may have deleterious consequences for marine organisms, particularly those with calcareous structures. We present a laboratory experiment to investigate this impact with general, introductory, environmental, and nonmajors chemistry students. For simplicity and homogeneity, calcite was…

  3. Cesium, manganese and cobalt water-sediment transfer kinetics and diffusion into mangrove sediments inferred by radiotracer experiments

    International Nuclear Information System (INIS)

    Machado, E.C.; Machado, W.; Patchineelam, S.R.

    2012-01-01

    A study on the trace elements transfer from tidal water to mangrove sediments from Guanabara Bay (southeastern Brazil) was performed in laboratory microcosms. Sediment cores were covered with tidal water spiked with 137 Cs, 54 Mn and 57 Co during 5-h experiments, and water samples were taken at regular intervals to measure uptake kinetics at the sediment-water interface. At the end of the experiments, the uptake and diffusional penetration into the sediments was evaluated. Half-removal times from water to sediments were slightly higher for 137 Cs (3.4 ± 1.7 h) than observed for 54 Mn (2.3 ± 0.2 h) and 57 Co (2.6 ± 1.1 h). After these experiments, all radioisotopes presented decreasing activities with increasing sediment depth, being the distribution of 137 Cs indicative of higher diffusion within the upper 2 cm. This study on the removal of 137 Cs, 54 Mn and 57 Co from tidal water by mangrove sediments suggests that while 57 Co and 54 Mn presented closer behaviors, there was a slightly higher mobility of 137 Cs. (author)

  4. An Enzyme Kinetics Experiment for the Undergraduate Organic Chemistry Laboratory

    Science.gov (United States)

    Olsen, Robert J.; Olsen, Julie A.; Giles, Greta A.

    2010-01-01

    An experiment using [superscript 1]H NMR spectroscopy to observe the kinetics of the acylase 1-catalyzed hydrolysis of "N"-acetyl-DL-methionine has been developed for the organic laboratory. The L-enantiomer of the reactant is hydrolyzed completely in less than 2 h, and [superscript 1]H NMR spectroscopic data from a single sample can be worked up…

  5. Simulating the volatilization of solvents in unsaturated soils during laboratory and field infiltration experiments

    Science.gov (United States)

    Cho, H. Jean; Jaffe, Peter R.; Smith, James A.

    1993-01-01

    This paper describes laboratory and field experiments which were conducted to study the dynamics of trichloroethylene (TCE) as it volatilized from contaminated groundwater and diffused in the presence of infiltrating water through the unsaturated soil zone to the land surface. The field experiments were conducted at the Picatinny Arsenal, which is part of the United States Geological Survey Toxic Substances Hydrology Program. In both laboratory and field settings the gas and water phase concentrations of TCE were not in equilibrium during infiltration. Gas-water mass transfer rate constants were calibrated to the experimental data using a model in which the water phase was treated as two phases: a mobile water phase and an immobile water phase. The mass transfer limitations of a volatile organic compound between the gas and liquid phases were described explicitly in the model. In the laboratory experiment the porous medium was nonsorbing, and water infiltration rates ranged from 0.076 to 0.28 cm h−1. In the field experiment the water infiltration rate was 0.34 cm h−1, and sorption onto the soil matrix was significant. The laboratory-calibrated gas-water mass transfer rate constant is 3.3×10−4 h−1 for an infiltration rate of 0.076 cm h−1 and 1.4×10−3 h−1 for an infiltration rate of 0.28 cm h−1. The overall mass transfer rate coefficients, incorporating the contribution of mass transfer between mobile and immobile water phases and the variation of interfacial area with moisture content, range from 3×10−4 h−1 to 1×10−2 h−1. A power law model relates the gas-water mass transfer rate constant to the infiltration rate and the fraction of the water phase which is mobile. It was found that the results from the laboratory experiments could not be extrapolated to the field. In order to simulate the field experiment the very slow desorption of TCE from the soil matrix was incorporated into the mathematical model. When desorption from the

  6. Background study of absorbed dose in biological experiments at the Modane Underground Laboratory

    Directory of Open Access Journals (Sweden)

    Lampe Nathanael

    2016-01-01

    Full Text Available Aiming to explore how biological systems respond to ultra-low background environ-ments, we report here our background studies for biological experiments in the Modane Under-ground Laboratory. We find that the minimum radioactive background for biology experiments is limited by the potassium content of the biological sample itself, coming from its nutritive me-dium, which we find in our experimental set-up to be 26 nGy hr-1. Compared to our reference radiation environment in Clermont-Ferrand, biological experiments can be conducted in the Modane laboratory with a radiation background 8.2 times lower than the reference above-ground level. As the radiation background may be further reduced by using different nutritive media, we also provide measurements of the potassium concentration by gamma spectroscopy of yeast extract (63.3±1.2 mg g-1 and tryptone (2.5±0.2 mg g-1 in order to guide media selection in future experiments.

  7. Isolation and Characterization of Agrobacterium Strains from Soil: A Laboratory Capstone Experience

    Directory of Open Access Journals (Sweden)

    Kim R. Finer

    2016-12-01

    Full Text Available In this investigation, the students’ goal was to isolate and characterize Agrobacterium strains from soil. Following selection and enrichment on 1A-t medium, putative Agrobacterium isolates were characterized by Gram stain reaction and biochemical tests. Isolates were further evaluated using polymerase chain reaction (PCR with different primer sets designed to amplify specific regions of bacterial deoxyribonucleic acid (DNA. Primer sets included AGRH to identify isolates that were members of the Rhizobiaceae, BIOVAR1 primers to identify members of Agrobacterium biovar group I, and a third set, VIRG, to determine presence of virG (only present in pathogenic Agrobacterium strains. During the investigation, students applied previously learned techniques including serial dilution, use of selective/differential media, staining protocols, biochemical analysis, molecular analysis via PCR, and electrophoresis. Students also gained practical experience using photo documentation to record data for an eventual mock journal publication of the capstone laboratory experience. Pre- and post-evaluation of class content knowledge related to the techniques, protocols, and learning objectives of these laboratories revealed significant learning gains in the content areas of Agrobacterium–plant interactions (p ≤ 0.001 and molecular biology (p ≤ 0.01. The capstone journal assignment served as the assessment tool to evaluate mastery and application of laboratory technique, the ability to accurately collect and evaluate data, and critical thinking skills associated with experimental troubleshooting and extrapolation. Analysis of journal reports following the capstone experience showed significant improvement in assignment scores (p ≤ 0.0001 and attainment of capstone experience learning outcomes.

  8. Investigating Affective Experiences in the Undergraduate Chemistry Laboratory: Students' Perceptions of Control and Responsibility

    Science.gov (United States)

    Galloway, Kelli R.; Malakpa, Zoebedeh; Bretz, Stacey Lowery

    2016-01-01

    Meaningful learning requires the integration of cognitive and affective learning with the psychomotor, i.e., hands-on learning. The undergraduate chemistry laboratory is an ideal place for meaningful learning to occur. However, accurately characterizing students' affective experiences in the chemistry laboratory can be a very difficult task. While…

  9. The Laboratory of the Mind Thought Experiments in the Natural Sciences

    CERN Document Server

    Brown, James Robert

    2010-01-01

    Newton's bucket, Einstein's elevator, Schrödinger's cat - these are some of the best-known examples of thought experiments in the natural sciences. But what function do these experiments perform? Are they really experiments at all? Can they help us gain a greater understanding of the natural world?  How is it possible that we can learn new things just by thinking?   In this revised and updated new edition of his classic text The Laboratory of the Mind, James Robert Brown continues to defend apriorism in the physical world. This edition features two new chapters, one on "counter

  10. Discovering Inexpensive, Effective Catalysts for Solar Energy Conversion: An Authentic Research Laboratory Experience

    Science.gov (United States)

    Shaner, Sarah E.; Hooker, Paul D.; Nickel, Anne-Marie; Leichtfuss, Amanda R.; Adams, Carissa S.; de la Cerda, Dionisia; She, Yuqi; Gerken, James B.; Pokhrel, Ravi; Ambrose, Nicholas J.; Khaliqi, David; Stahl, Shannon S.; Schuttlefield Christus, Jennifer D.

    2016-01-01

    Electrochemical water oxidation is a major focus of solar energy conversion efforts. A new laboratory experiment has been developed that utilizes real-time, hands-on research to discover catalysts for solar energy conversion. The HARPOON, or Heterogeneous Anodes Rapidly Perused for Oxygen Overpotential Neutralization, experiment allows an array of…

  11. Investigation of microbial community structure in constructed mangrove microcosms receiving wastewater-borne polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs)

    International Nuclear Information System (INIS)

    Wang, Ya-fen; Wu, Yan; Pi, Na; Tam, Nora Fung-yee

    2014-01-01

    The study aims to examine relationships between microbial community structure and mixed pollutants of polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs) in constructed wetland microcosms, planted with Excoecaria agallocha or Kandelia obovata, two common mangrove plant species, and under two tidal regimes, everyday tidal (Te) and no tidal flooding (Tn). Results showed both microbial community structure and the retained amounts of pollutants were significantly determined by tidal regime, while the effect of plant species was small. Higher amounts of PAHs but lower amounts of PBDEs were always retained in sediments under Te than Tn regimes. Accordingly, temporal and vertical distributions of microbial community structure differed greatly between the two tidal regimes. Redundancy analysis further revealed significant correlation between a subgroup of the mixed PAHs and PBDEs with variation in microbial community structure. The findings will help to propose specific strategies to improve the bioremediation efficiency of constructed wetland. - Highlights: • We found synchronous degradation of PAHs and PBDEs in constructed mangrove microcosms. • Retained amounts of PAHs and PBDEs were determined mainly by tidal regime. • Tidal regime in turn significantly determined microbial community structure. • Variations of microbial EL-FAME profiles were more affected by PBDEs than PAHs. • Bap and BDE-154 were two most influential pollutants on microbial community structure. - Sedimentary microbial community structure was significantly determined by tidal regime, which in turn determined retained amounts of PAHs and PBDEs in constructed mangrove microcosms

  12. Molecular- and cultivation-based analyses of microbial communities in oil field water and in microcosms amended with nitrate to control H{sub 2}S production

    Energy Technology Data Exchange (ETDEWEB)

    Kumaraswamy, Raji; Ebert, Sara; Fedorak, Phillip M.; Foght, Julia M. [Alberta Univ., Edmonton, AB (Canada). Biological Sciences; Gray, Murray R. [Alberta Univ., Edmonton, AB (Canada). Chemical and Materials Engineering

    2011-03-15

    Nitrate injection into oil fields is an alternative to biocide addition for controlling sulfide production ('souring') caused by sulfate-reducing bacteria (SRB). This study examined the suitability of several cultivation-dependent and cultivation-independent methods to assess potential microbial activities (sulfidogenesis and nitrate reduction) and the impact of nitrate amendment on oil field microbiota. Microcosms containing produced waters from two Western Canadian oil fields exhibited sulfidogenesis that was inhibited by nitrate amendment. Most probable number (MPN) and fluorescent in situ hybridization (FISH) analyses of uncultivated produced waters showed low cell numbers ({<=}10{sup 3} MPN/ml) dominated by SRB (>95% relative abundance). MPN analysis also detected nitrate-reducing sulfide-oxidizing bacteria (NRSOB) and heterotrophic nitrate-reducing bacteria (HNRB) at numbers too low to be detected by FISH or denaturing gradient gel electrophoresis (DGGE). In microcosms containing produced water fortified with sulfate, near-stoichiometric concentrations of sulfide were produced. FISH analyses of the microcosms after 55 days of incubation revealed that Gammaproteobacteria increased from undetectable levels to 5-20% abundance, resulting in a decreased proportion of Deltaproteobacteria (50-60% abundance). DGGE analysis confirmed the presence of Delta- and Gammaproteobacteria and also detected Bacteroidetes. When sulfate-fortified produced waters were amended with nitrate, sulfidogenesis was inhibited and Deltaproteobacteria decreased to levels undetectable by FISH, with a concomitant increase in Gammaproteobacteria from below detection to 50-60% abundance. DGGE analysis of these microcosms yielded sequences of Gamma- and Epsilonproteobacteria related to presumptive HNRB and NRSOB (Halomonas, Marinobacterium, Marinobacter, Pseudomonas and Arcobacter), thus supporting chemical data indicating that nitrate-reducing bacteria out-compete SRB when nitrate is

  13. The Equilibrium Constant for Bromothymol Blue: A General Chemistry Laboratory Experiment Using Spectroscopy

    Science.gov (United States)

    Klotz, Elsbeth; Doyle, Robert; Gross, Erin; Mattson, Bruce

    2011-01-01

    A simple, inexpensive, and environmentally friendly undergraduate laboratory experiment is described in which students use visible spectroscopy to determine a numerical value for an equilibrium constant, K[subscript c]. The experiment correlates well with the lecture topic of equilibrium even though the subject of the study is an acid-base…

  14. Spherical wave particle velocities in geologic materials from laboratory experiments

    International Nuclear Information System (INIS)

    Cizek, J.C.; Florence, A.L.

    1983-01-01

    Particle velocity records that describe spherical waves in rock simulants, tuffs, salt, and granite have been obtained in laboratory experiments. The records aid the modeling of constitutive equations for continuum mechanics codes used in DNA containment research. The technique has also been applied to investigate containment-related problems involving material poperties, failure criteria, scaling, decoupling, and residual strain field relaxation. 22 figures

  15. Dechlorinating ability of TCE-fed microcosms with different electron donors

    International Nuclear Information System (INIS)

    Panagiotakis, Iraklis; Mamais, Daniel; Pantazidou, Marina; Marneri, Matina; Parapouli, Maria; Hatziloukas, Efstathios; Tandoi, Valter

    2007-01-01

    The main objective of the work presented herein is to assess the effect of different electron donors (butyric acid and methanol) on the dechlorinating activity of two microbial cultures where active methanogenic populations are present, in an effort to evaluate the importance of the electron donor selection process. The ability of each anaerobic culture to dechlorinate TCE, when enriched with either butyric acid or methanol, was verified based on the results of gas chromatography. In addition, the fluorescent in situ hybridization (FISH) and the polymerase chain reaction (PCR) methods gave positive results for the presence of Dehalococcoides spp. According to results of the batch tests conducted in this study, it appears that the selection of the electron donor for stimulating TCE dechlorination depends on microbial culture composition; therefore, the decision on the appropriate electron donor should be based on site-specific microcosm studies

  16. Cross-disciplinary thermoregulation and sweat analysis laboratory experiences for undergraduate Chemistry and Exercise Science students.

    Science.gov (United States)

    Mulligan, Gregory; Taylor, Nichole; Glen, Mary; Tomlin, Dona; Gaul, Catherine A

    2011-06-01

    Cross-disciplinary (CD) learning experiences benefit student understanding of concepts and curriculum by offering opportunities to explore topics from the perspectives of alternate fields of study. This report involves a qualitative evaluation of CD health sciences undergraduate laboratory experiences in which concepts and students from two distinct disciplines [chemistry (CHEM) and exercise physiology (EPHE)] combined to study exercise thermoregulation and sweat analysis. Twenty-eight senior BSc Kinesiology (EPHE) students and 42 senior BSc CHEM students participated as part of their mutually exclusive, respective courses. The effectiveness of this laboratory environment was evaluated qualitatively using written comments collected from all students as well as from formal focus groups conducted after the CD laboratory with a representative cohort from each class (n = 16 CHEM students and 9 EPHE students). An open coding strategy was used to analyze the data from written feedback and focus group transcripts. Coding topics were generated and used to develop five themes found to be consistent for both groups of students. These themes reflected the common student perceptions that the CD experience was valuable and that students enjoyed being able to apply academic concepts to practical situations as well as the opportunity to interact with students from another discipline of study. However, students also reported some challenges throughout this experience that stemmed from the combination of laboratory groups from different disciplines with limited modification to the design of the original, pre-CD, learning environments. The results indicate that this laboratory created an effective learning opportunity that fostered student interest and enthusiasm for learning. The findings also provide information that could inform subsequent design and implementation of similar CD experiences to enhance engagement of all students and improve instructor efficacy.

  17. Two-dimensional flow-through microcosms - Versatile test systems to study biodegradation processes in porous aquifers

    Science.gov (United States)

    Bauer, Robert D.; Rolle, Massimo; Kürzinger, Petra; Grathwohl, Peter; Meckenstock, Rainer U.; Griebler, Christian

    2009-05-01

    SummaryA fundamental prerequisite of any remedial activity is a sound knowledge of both the biotic and abiotic processes involved in transport and degradation of contaminants. Investigations of these aspects in situ often seem infeasible due to the complexity of interacting processes. A simplified portrayal of nature can be facilitated in laboratory-based two-dimensional (2D) sediment flow-through microcosms. This paper describes the versatility of such simple aquifer model systems with respect to biodegradation of aromatic hydrocarbons, i.e. toluene and ethylbenzene, under various environmental conditions. Initially constructed to study non-reactive and bioreactive transport of organic contaminants in homogeneous porous media under steady state hydraulic conditions, experimental setups developed towards more realistic heterogeneous sediment packing and transient hydraulic conditions. High-resolution spatial and temporal sampling allowed to obtain new insights on the distribution of bioactivities in contaminant plumes and associated controlling and limiting factors. Major biodegradation activities in saturated porous sediments are located at the fringes of contaminant plumes and are driven by dispersive mixing. These hot-spots of contaminant biotransformation are characterized by steep physical-chemical gradients in the millimeter to centimeter range. Sediment heterogeneity, i.e. high-conductivity zones, was shown to significantly enhance transverse mixing and subsequently biodegradation. On the contrary, transient hydraulic conditions may generate intermediate disturbances to biodegrader populations and thus may interfere with optimized contaminant conversion. However, a bacterial strain aerobically degrading toluene, i.e. Pseudomonas putida F1, was shown to adapt to vertically moving contaminant plumes, in the way that it regained full biodegradation potential two-times faster in areas with a mid-term (days to weeks) contamination history than in areas not

  18. Thermodynamic Exploration of Eosin-Lysozyme Binding: A Physical Chemistry and Biochemistry Laboratory Experiment

    Science.gov (United States)

    Huisman, Andrew J.; Hartsell, Lydia R.; Krueger, Brent P.; Pikaart, Michael J.

    2010-01-01

    We developed a modular pair of experiments for use in the undergraduate physical chemistry and biochemistry laboratories. Both experiments examine the thermodynamics of the binding of a small molecule, eosin Y, to the protein lysozyme. The assay for binding is the quenching of lysozyme fluorescence by eosin through resonant energy transfer. In…

  19. Biological 12C-13C fractionation increases with increasing community-complexity in soil microcosms

    DEFF Research Database (Denmark)

    Yang, Weijun; Magid, Jakob; Christensen, Søren

    2014-01-01

    -rates and determine the trophic level of organisms in biological systems. While it is widely accepted that 15N-accumulates in natural food-chains, it is disputed to which extent this is the case for C-13. We constructed sand-microcosms inoculated with a dilution series of soil organisms and amended with glucose......Isotope fractionation is a ubiquitous phenomenon in natural ecosystems. When chemical elements move through food chains, natural isotope ratios change because biological processes tend to discriminate against heavier isotopes. This effect can be used to trace flows of matter, estimate process...

  20. Stratospheric controlled perturbation experiment (SCoPEx): overview, status, and results from related laboratory experiments

    Science.gov (United States)

    Keith, D.; Dykema, J. A.; Keutsch, F. N.

    2017-12-01

    Stratospheric Controlled Perturbation Experiment (SCoPEx), is a scientific experiment to advance understanding of stratospheric aerosols. It aims to make quantitative measurements of aerosol microphysics and atmospheric chemistry to improve large-scale models used to assess the risks and benefits of solar geoengineering. A perturbative experiment requires: (a) means to create a well-mixed, small perturbed volume, and (b) observation of time evolution of chemistry and aerosols in the volume. SCoPEx will used a propelled balloon gondola containing all instruments and drive system. The propeller wake forms a well-mixed volume (roughly 1 km long and 100 meters in diameter) that serves as an experimental `beaker' into which aerosols (e.g., budget, etc; (d) results from CFD simulation of propeller wake and simulation of chemistry and aerosol microphysics; and finally (e) proposed concept of operations and schedule. We will also provide an overview of the plans for governance including management of health safety and environmental risks, transparency, public engagement, and larger questions about governance of solar geoengineering experiments. Finally, we will briefly present results of laboratory experiments of the interaction of chemical such as ClONO2 and HCl on particle surfaces relevant for stratospheric solar geoengineering.

  1. Arbuscular-mycorrhizal networks inhibit Eucalyptus tetrodonta seedlings in rain forest soil microcosms.

    Directory of Open Access Journals (Sweden)

    David P Janos

    Full Text Available Eucalyptus tetrodonta, a co-dominant tree species of tropical, northern Australian savannas, does not invade adjacent monsoon rain forest unless the forest is burnt intensely. Such facilitation by fire of seedling establishment is known as the "ashbed effect." Because the ashbed effect might involve disruption of common mycorrhizal networks, we hypothesized that in the absence of fire, intact rain forest arbuscular mycorrhizal (AM networks inhibit E. tetrodonta seedlings. Although arbuscular mycorrhizas predominate in the rain forest, common tree species of the northern Australian savannas (including adult E. tetrodonta host ectomycorrhizas. To test our hypothesis, we grew E. tetrodonta and Ceiba pentandra (an AM-responsive species used to confirm treatments separately in microcosms of ambient or methyl-bromide fumigated rain forest soil with or without severing potential mycorrhizal fungus connections to an AM nurse plant, Litsea glutinosa. As expected, C. pentandra formed mycorrhizas in all treatments but had the most root colonization and grew fastest in ambient soil. E. tetrodonta seedlings also formed AM in all treatments, but severing hyphae in fumigated soil produced the least colonization and the best growth. Three of ten E. tetrodonta seedlings in ambient soil with intact network hyphae died. Because foliar chlorosis was symptomatic of iron deficiency, after 130 days we began to fertilize half the E. tetrodonta seedlings in ambient soil with an iron solution. Iron fertilization completely remedied chlorosis and stimulated leaf growth. Our microcosm results suggest that in intact rain forest, common AM networks mediate belowground competition and AM fungi may exacerbate iron deficiency, thereby enhancing resistance to E. tetrodonta invasion. Common AM networks-previously unrecognized as contributors to the ashbed effect-probably help to maintain the rain forest-savanna boundary.

  2. Ideas in Practice (3): A Simulated Laboratory Experience in Digital Design.

    Science.gov (United States)

    Cleaver, Thomas G.

    1988-01-01

    Gives an example of the use of a simplified logic simulator in a logic design course. Discusses some problems in logic design classes, commercially available software, and software problems. Describes computer-aided engineering (CAE) software. Lists 14 experiments in the simulated laboratory and presents students' evaluation of the course. (YP)

  3. Microscale Organic Laboratory II: The Benefits Derived from Conversion to the Program and Representative Experiments.

    Science.gov (United States)

    Mayo, Dana W.; And Others

    1985-01-01

    Smaller amounts of materials are used in organic chemistry experiments as a means of improving air quality in the laboratory. Outlines benefits from this approach and describes two representative experiments in detail. These experiments are the Cannizzaro reaction and preparation of an aromatic nitrile. (JN)

  4. High Pb concentration stress on Typha latifolia growth and Pb removal in microcosm wetlands.

    Science.gov (United States)

    Han, Jianqiu; Chen, Fengzhen; Zhou, Yumei; Wang, Chaohua

    2015-01-01

    When constructed wetlands are used to treat high-Pb wastewater, Pb may become a stress to wetland plants, which subsequently reduces treatment performance and the other ecosystem services. To facilitate the design and operation of constructed wetlands for treatment of Pb-rich wastewater, we investigated the irreversible inhibitory level of Pb for Typha latifolia through experiments in microcosm wetlands. Seven horizontal subsurface flow constructed wetlands were built with rectangular plastic tanks and packed with marble chips and sand. All wetlands were transplanted with nine stems of Typha latifolia each. The wetlands were batch operated in a greenhouse with artificial wastewater (10 L each) for 12 days. Influent to the seven wetlands had different concentrations of Pb: 0 mg/L, 10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, 200 mg/L, and 500 mg/L, respectively. The results suggested that leaf chlorophyll relative content, relative growth rate, photosynthetic characteristics, activities of superoxide dismutase, peroxidase, and content of malondialdehyde were not affected when initial Pb concentration was at 100 mg/L and below. But when initial Pb concentration was above 100 mg/L, all of them were seriously affected. We conclude that high Pb concentrations wastewater could inhibit the growth of Typha latifolia and decrease the removal rate of wetlands.

  5. Bacterial community shift in the coastal Gulf of Mexico salt-marsh sediment microcosm in vitro following exposure to the Mississippi Canyon Block 252 oil (MC252)

    KAUST Repository

    Koo, Hyunmin; Mojib, Nazia; Huang, Jonathan P.; Donahoe, Rona J.; Bej, Asim K.

    2014-01-01

    In this study, we examined the responses by the indigenous bacterial communities in salt-marsh sediment microcosms in vitro following treatment with Mississippi Canyon Block 252 oil (MC252). Microcosms were constructed of sediment and seawater collected from Bayou La Batre located in coastal Alabama on the Gulf of Mexico. We used an amplicon pyrosequencing approach on microcosm sediment metagenome targeting the V3–V5 region of the 16S rRNA gene. Overall, we identified a shift in the bacterial community in three distinct groups. The first group was the early responders (orders Pseudomonadales and Oceanospirillales within class Gammaproteobacteria), which increased their relative abundance within 2 weeks and were maintained 3 weeks after oil treatment. The second group was identified as early, but transient responders (order Rhodobacterales within class Alphaproteobacteria; class Epsilonproteobacteria), which increased their population by 2 weeks, but returned to the basal level 3 weeks after oil treatment. The third group was the late responders (order Clostridiales within phylum Firmicutes; order Methylococcales within class Gammaproteobacteria; and phylum Tenericutes), which only increased 3 weeks after oil treatment. Furthermore, we identified oil-sensitive bacterial taxa (order Chromatiales within class Gammaproteobacteria; order Syntrophobacterales within class Deltaproteobacteria), which decreased in their population after 2 weeks of oil treatment. Detection of alkane (alkB), catechol (C2,3DO) and biphenyl (bph) biodegradation genes by PCR, particularly in oil-treated sediment metacommunity DNA, delineates proliferation of the hydrocarbon degrading bacterial community. Overall, the indigenous bacterial communities in our salt-marsh sediment in vitro microcosm study responded rapidly and shifted towards members of the taxonomic groups that are capable of surviving in an MC252 oil-contaminated environment.

  6. Bacterial community shift in the coastal Gulf of Mexico salt-marsh sediment microcosm in vitro following exposure to the Mississippi Canyon Block 252 oil (MC252)

    KAUST Repository

    Koo, Hyunmin

    2014-07-10

    In this study, we examined the responses by the indigenous bacterial communities in salt-marsh sediment microcosms in vitro following treatment with Mississippi Canyon Block 252 oil (MC252). Microcosms were constructed of sediment and seawater collected from Bayou La Batre located in coastal Alabama on the Gulf of Mexico. We used an amplicon pyrosequencing approach on microcosm sediment metagenome targeting the V3–V5 region of the 16S rRNA gene. Overall, we identified a shift in the bacterial community in three distinct groups. The first group was the early responders (orders Pseudomonadales and Oceanospirillales within class Gammaproteobacteria), which increased their relative abundance within 2 weeks and were maintained 3 weeks after oil treatment. The second group was identified as early, but transient responders (order Rhodobacterales within class Alphaproteobacteria; class Epsilonproteobacteria), which increased their population by 2 weeks, but returned to the basal level 3 weeks after oil treatment. The third group was the late responders (order Clostridiales within phylum Firmicutes; order Methylococcales within class Gammaproteobacteria; and phylum Tenericutes), which only increased 3 weeks after oil treatment. Furthermore, we identified oil-sensitive bacterial taxa (order Chromatiales within class Gammaproteobacteria; order Syntrophobacterales within class Deltaproteobacteria), which decreased in their population after 2 weeks of oil treatment. Detection of alkane (alkB), catechol (C2,3DO) and biphenyl (bph) biodegradation genes by PCR, particularly in oil-treated sediment metacommunity DNA, delineates proliferation of the hydrocarbon degrading bacterial community. Overall, the indigenous bacterial communities in our salt-marsh sediment in vitro microcosm study responded rapidly and shifted towards members of the taxonomic groups that are capable of surviving in an MC252 oil-contaminated environment.

  7. Laboratory Astrophysics Experiments to Study Star Formation

    Science.gov (United States)

    Young, Rachel

    As a thesis project, I devised and implemented a scaled accretion shock experiment on the OMEGA laser (Laboratory for Laser Energetics). This effort marked the first foray into the growing field of laser-created magnetized flowing plasmas for the Center for Laser Experimental Astrophysical Research (CLEAR) here at the University of Michigan. Accretion shocks form when streams of accreting material fall to the surface of a young, growing star along magnetic field lines and, due to their supersonic flow, create shocks. As I was concerned with what was happening immediately on the surface of the star where the shock forms, I scaled the system by launching a plasma jet (the "accreting flow") and driving it into a solid surface (the "stellar surface") in the presence of an imposed magnetic field parallel to the jet flow (locally analogous to the dipole field of the star). Early work for this thesis project was dedicated to building a magnetized flowing plasma platform at CLEAR. I investigated a method for launching collimated plasma jets and studied them using Thomson scattering, a method which measures parameters such as temperature and density by scattering a probe beam off the experimental plasma. Although the data were corrupted with probe heating effects, I overcame this problem by finding the mass density of the jets and using it to determine they were isothermal rarefactions with a temperature of 6 eV. Scaling an astrophysical phenomenon to the laboratory requires tailoring the parameters of the experiment to preserve its physics, rather than creating an experiment that merely superficially resembles it. I ensured this by distilling the driving physical processes of the astrophysical system--accretion shocks--into a list of dimensionless number constraints and mapping these into plasma parameter space. Due to this project being the first magnetized flowing plasma effort at CLEAR, it suffered the growing pains typical of a young research program. Of my two primary

  8. CANDU steam generator life management: laboratory data and plant experience

    International Nuclear Information System (INIS)

    Tapping, R.L.; Nickerson, J.H.; Subash, N.; Wright, M.D.

    2001-10-01

    As CANDU reactors enter middle age, and the potential value of the plants in a deregulated market is realized, life management and life extension issues become increasingly important. An accurate assessment of critical components, such as the CANDU 6 steam generators (SGs), is crucial for successful life extension, and in this context, material issues are a key factor. For example, service experience with Alloy 900 tubing indicates very low levels of degradation within CANDU SGs; the same is also noted worldwide. With little field data for extrapolation, life management and life extension decisions for the tube bundles rely heavily on laboratory data. Similarly, other components of the SGs, in particular the secondary side internals, have only limited inspection data upon which to base a condition assessment. However, in this case there are also relatively little laboratory data. Decisions on life management and life extension are further complicated--not only is inspection access often restricted, but repair or replacement options for internal components are, by definition, also limited. The application of CANDU SG life management and life extension requires a judicious blend of in-service data, laboratory research and development (R and D) and materials and engineering judgment. For instance, the available laboratory corrosion and fretting wear data for Alloy 800 SG tubing have been compared with plant experience (with all types of tubing), and with crevice chemistry simulations, in order to provide an appropriate inspection guide for a 50-year SG life. A similar approach has been taken with other SG components, where the emphasis has been on known degradation mechanisms worldwide. This paper provides an outline of the CANDU SG life management program, including the results to date, a summary of the supporting R and D program showing the integration with condition assessment and life management activities, and the approach taken to life extension for a typical

  9. Pre-test simulations of laboratory-scale heater experiments in tuff. Yucca Mountain Site Characterization Project

    International Nuclear Information System (INIS)

    Ho, Clifford K.

    1995-09-01

    Laboratory-scale heater experiments are Proposed to observe thermohydrologic Processes in tuffaceous rock using existing equipment and x-ray imaging techniques. The purpose of the experiments is to gain understanding of the near-field behavior and thermodynamic environment surrounding a heat source. As a prelude to these experiments, numerical simulations are performed to determine design-related parameters such as optimal heating power and heating duration. In addition, the simulations aid in identifying and understanding thermal processes and mechanisms that may occur under a variety of experimental conditions. Results of the simulations show that convection may play an important role in the heat transfer and thermodynamic environment of the heater if the Rayleigh-Darcy number exceeds a critical value (= 10 for the laboratory experiments) depending on the type of backfill material within the annulus (or drift)

  10. Temporal succession in carbon incorporation from macromolecules by particle-attached bacteria in marine microcosms: Particle-attached bacteria incorporating organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Mayali, Xavier [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stewart, Benjamin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mabery, Shalini [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, Peter K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-12-21

    Here, we investigated bacterial carbon assimilation from stable isotope-labelled macromolecular substrates (proteins; lipids; and two types of polysaccharides, starch and cellobiose) while attached to killed diatom detrital particles during laboratory microcosms incubated for 17 days. Using Chip-SIP (secondary ion mass spectrometry analysis of RNA microarrays), we identified generalist operational taxonomic units (OTUs) from the Gammaproteobacteria, belonging to the genera Colwellia, Glaciecola, Pseudoalteromonas and Rheinheimera, and from the Bacteroidetes, genera Owenweeksia and Maribacter, that incorporated the four tested substrates throughout the incubation period. Many of these OTUs exhibited the highest isotope incorporation relative to the others, indicating that they were likely the most active. Additional OTUs from the Gammaproteobacteria, Bacteroidetes and Alphaproteobacteria exhibited generally (but not always) lower activity and did not incorporate all tested substrates at all times, showing species succession in organic carbon incorporation. We also found evidence to suggest that both generalist and specialist OTUs changed their relative substrate incorporation over time, presumably in response to changing substrate availability as the particles aged. This pattern was demonstrated by temporal succession from relatively higher starch incorporation early in the incubations, eventually switching to higher cellobiose incorporation after 2 weeks.

  11. The generation and amplification of intergalactic magnetic fields in analogue laboratory experiments with high power lasers

    Science.gov (United States)

    Gregori, G.; Reville, B.; Miniati, F.

    2015-11-01

    The advent of high-power laser facilities has, in the past two decades, opened a new field of research where astrophysical environments can be scaled down to laboratory dimensions, while preserving the essential physics. This is due to the invariance of the equations of magneto-hydrodynamics to a class of similarity transformations. Here we review the relevant scaling relations and their application in laboratory astrophysics experiments with a focus on the generation and amplification of magnetic fields in cosmic environment. The standard model for the origin of magnetic fields is a multi stage process whereby a vanishing magnetic seed is first generated by a rotational electric field and is then amplified by turbulent dynamo action to the characteristic values observed in astronomical bodies. We thus discuss the relevant seed generation mechanisms in cosmic environment including resistive mechanism, collision-less and fluid instabilities, as well as novel laboratory experiments using high power laser systems aimed at investigating the amplification of magnetic energy by magneto-hydrodynamic (MHD) turbulence. Future directions, including efforts to model in the laboratory the process of diffusive shock acceleration are also discussed, with an emphasis on the potential of laboratory experiments to further our understanding of plasma physics on cosmic scales.

  12. Comparative analysis of bacterial community-metagenomics in coastal Gulf of Mexico sediment microcosms following exposure to Macondo oil (MC252)

    KAUST Repository

    Koo, Hyunmin

    2014-09-10

    The indigenous bacterial communities in sediment microcosms from Dauphin Island (DI), Petit Bois Island (PB) and Perdido Pass (PP) of the coastal Gulf of Mexico were compared following treatment with Macondo oil (MC252) using pyrosequencing and culture-based approaches. After quality-based trimming, 28,991 partial 16S rRNA sequence reads were analyzed by rarefaction, confirming that analyses of bacterial communities were saturated with respect to species diversity. Changes in the relative abundances of Proteobacteria, Bacteroidetes and Firmicutes played an important role in structuring bacterial communities in oil-treated sediments. Proteobacteria were dominant in oil-treated samples, whereas Firmicutes and Bacteroidetes were either the second or the third most abundant taxa. Tenericutes, members of which are known for oil biodegradation, were detected shortly after treatment, and continued to increase in DI and PP sediments. Multivariate statistical analyses (ADONIS) revealed significant dissimilarity of bacterial communities between oil-treated and untreated samples and among locations. In addition, a similarity percentage analysis showed the contribution of each species to the contrast between untreated and oil-treated samples. PCR amplification using DNA from pure cultures of Exiguobacterium,  Pseudoalteromonas,  Halomonas and Dyadobacter, isolated from oil-treated microcosm sediments, produced amplicons similar to polycyclic aromatic hydrocarbon-degrading genes. In the context of the 2010 Macondo blowout, the results from our study demonstrated that the indigenous bacterial communities in coastal Gulf of Mexico sediment microcosms responded to the MC252 oil with altered community structure and species composition. The rapid proliferation of hydrocarbonoclastic bacteria suggests their involvement in the degradation of the spilt oil in the Gulf of Mexico ecosystem.

  13. LABORATORY EXPERIMENTS TO SIMULATE CO2 OCEAN DISPOSAL

    Energy Technology Data Exchange (ETDEWEB)

    Stephen M. Masutani

    1999-12-31

    This Final Technical Report summarizes the technical accomplishments of an investigation entitled ''Laboratory Experiments to Simulate CO{sub 2} Ocean Disposal'', funded by the U.S. Department of Energy's University Coal Research Program. This investigation responds to the possibility that restrictions on greenhouse gas emissions may be imposed in the future to comply with the Framework Convention on Climate Change. The primary objective of the investigation was to obtain experimental data that can be applied to assess the technical feasibility and environmental impacts of oceanic containment strategies to limit release of carbon dioxide (CO{sub 2}) from coal and other fossil fuel combustion systems into the atmosphere. A number of critical technical uncertainties of ocean disposal of CO{sub 2} were addressed by performing laboratory experiments on liquid CO{sub 2} jet break-up into a dispersed droplet phase, and hydrate formation, under deep ocean conditions. Major accomplishments of this study included: (1) five jet instability regimes were identified that occur in sequence as liquid CO{sub 2} jet disintegration progresses from laminar instability to turbulent atomization; (2) linear regression to the data yielded relationships for the boundaries between the five instability regimes in dimensionless Ohnesorge Number, Oh, and jet Reynolds Number, Re, space; (3) droplet size spectra was measured over the full range of instabilities; (4) characteristic droplet diameters decrease steadily with increasing jet velocity (and increasing Weber Number), attaining an asymptotic value in instability regime 5 (full atomization); and (5) pre-breakup hydrate formation appears to affect the size distribution of the droplet phase primary by changing the effective geometry of the jet.

  14. Culturing Toxic Benthic Blooms: The Fate of Natural Biofilms in a Microcosm System

    Directory of Open Access Journals (Sweden)

    Francesca Di Pippo

    2017-08-01

    Full Text Available A microcosm designed for culturing aquatic phototrophic biofilms on artificial substrata was used to perform experiments with microphytobenthos sampled during summer toxic outbreaks of Ostreopsis cf. ovata along the Middle Tyrrhenian coast. This dynamic approach aimed at exploring the unique and complex nature of O. cf. ovata bloom development in the benthic system. Epibenthic assemblages were used as inocula for co-cultures of bloom organisms on polycarbonate slides at controlled environmental conditions. Biofilm surface adhesion, growth, and spatial structure were evaluated along with shifts in composition and matrix production in a low disturbance regime, simulating source habitat. Initial adhesion and substratum colonisation appeared as stochastic processes, then community structure and physiognomy markedly changed with time. Dominance of filamentous cyanobacteria and diatoms, and dense clusters of Amphidinium cf. carterae at the mature biofilm phases, were recorded by light and confocal microscopy, whilst O. cf. ovata growth was visibly limited in the late culture phases. Life-form strategies, competitiveness for resources, and possibly allelopathic interactions shaped biofilm structure during culture growth. HPLC (High Performance Liquid Chromatography analysis of exopolysaccharidic matrix revealed variations in sugar total amounts and composition. No toxic compounds were detected in the final communities tested by LC-MS (Liquid Chromatography- Mass Spectrometry and MALDI-TOF MS (Matrix Assisted Laser Desorption Ionization Time OF Flight Mass Spectroscopy techniques.

  15. Calibration Laboratory for Medical Physics towards ISO/ IEC 17025 accreditation: Experience and challenges

    International Nuclear Information System (INIS)

    Asmaliza Hashim; Abdul Aziz Ramli; Muhammad Jamal Isa; Sharul Azlan Azizan

    2011-01-01

    Medical Physics Calibration Laboratory is laboratory where placed under Medical Physics Group, Radiation Healthy and Safety Division. This laboratory offers calibration services to their customers that covered doses calibration, tube voltan (kVp), exposure doses, sensitometer and densitometer. After 12 years of operation, it is the right time for this laboratory to upgrade their quality services based on ISO/ IEC 17025. Accreditation scope covered calibration for diagnostic doses only. Starting from 2009, serious effort was done to prepare the quality documents that covered quality manual, quality procedure and work orders. Meanwhile, several series of audit were done by Quality Management Center (QMC), now Innovation Management Center (IMC) with collaboration with Standard Department. This paper works revealed challenges and experience during the process toward ISO/ IEC 17025 accreditation. (author)

  16. An Enzymatic Clinical Chemistry Laboratory Experiment Incorporating an Introduction to Mathematical Method Comparison Techniques

    Science.gov (United States)

    Duxbury, Mark

    2004-01-01

    An enzymatic laboratory experiment based on the analysis of serum is described that is suitable for students of clinical chemistry. The experiment incorporates an introduction to mathematical method-comparison techniques in which three different clinical glucose analysis methods are compared using linear regression and Bland-Altman difference…

  17. Experiments at The Virtual National Laboratory for Heavy Ion Fusion

    International Nuclear Information System (INIS)

    Seidl, P.A.; Bieniosek, F.M.; Celata, C.M.; Faltens, A.; Kwan, J.W.; MacLaren, S.A.; Ponce, D.; Shuman, D.; Yu, S.; Ahle, L.; Lund, S.; Molvik, A.; Sangster, T.C.

    2000-01-01

    An overview of experiments is presented, in which the physical dimensions, emittance and perveance are scaled to explore driver-relevant beam dynamics. Among these are beam merging, focusing to a small spot, and bending and recirculating beams. The Virtual National Laboratory for Heavy Ion Fusion (VNL) is also developing two driver-scale beam experiments involving heavy-ion beams with I(sub beam) about 1 Ampere to provide guidance for the design of an Integrated Research Experiment (IRE) for driver system studies within the next 5 years. Multiple-beam sources and injectors are being designed and a one-beam module will be built and tested. Another experimental effort will be the transport of such a beam through about 100 magnetic quadrupoles. The experiment will determine transport limits at high aperture fill factors, beam halo formation, and the influence on beam properties of secondary electron Research into driver technology will be briefly presented, including the development of ferromagnetic core materials, induction core pulsers, multiple-beam quadrupole arrays and plasma channel formation experiments for pinched transport in reactor chambers

  18. Evaluation of the biodegradability of petroleum in microcosm systems by using mangrove sediments from Camamu Bay, Bahia, Brazil.

    Science.gov (United States)

    Santos, A C F; Rezende, R P; Brendel, M; Souza, S S; Gonçalves, A C S; Dias, J C T

    2014-03-24

    We investigated the biodegradability of oil in mangrove sediment from Camamu Bay and measured its effect on the bacterial community. Microcosms of mangrove sediment were contaminated with 0.1, 0.5, 1, 2, and 5% (w/v) oil, and the microbial activity was compared to that in uncontaminated sediment. The evolution of CO2 and gas chromatography showed the mineralization of oil compounds, which could reach 100%. Bacterial diversity was determined by polymerase chain reaction using a set of primers for the V3 and V6-V8 regions of 16S rDNA. The band profile obtained by denaturing gradient gel electrophoresis of the amplicons that were obtained for the V3 region showed a negative correlation between band number and oil concentration, whereas that of the V6-V8 region showed a positive correlation between band numbers and oil concentration. The latter also gave similar results for microcosms that were contaminated with 2 and 5% oil. These results demonstrate the mangrove sediment's capacity to recover from oil contamination (in vitro) and suggest that native mangrove microorganisms contain enzymes necessary for the catabolism of oil.

  19. Laboratory Experiments on Meandering Meltwater Channels

    Science.gov (United States)

    Fernandez, R.; Berens, J.; Parker, G.; Stark, C. P.

    2017-12-01

    Meandering channels of all scales and flowing over a wide variety of media have common planform patterns. Although the analogy in planform suggests there is a common underlying framework, the constitutive relations driving planform evolution through vertical incision/deposition and lateral migration differ from medium to medium. The driving processes in alluvial and mixed bedrock-alluvial meandering channels have been studied substantially over the last decades. However, this is not the case for meandering channels in other media such as ice or soluble rock. Here we present results from experiments conducted at the Ven Te Chow Hydrosystems Laboratory of the University of Illinois at Urbana-Champaign on meltwater meandering channels. A rivulet is carved into an ice block and water is allowed to flow at a constant discharge. Planform evolution is analyzed with time lapse imaging and complemented with rubber molds of the channel once the experiment is over. These molds give us the full 3D structure of the meandering, including incisional overhang. Vertical incision rates are measured throughout the run by taking elevations along the channel, and these measurements are complemented with analysis from the molds. We show examples of meandering of intense amplitude with deep overhangs. Features resembling scroll bars document cyclically punctuated melting. We report on lateral migration rates, incision rates, sinuosity, channel depths, channel widths, reach averaged velocities, bend wavelengths and amplitudes and compare them to values reported in the literature for alluvial rivers.

  20. Evidence of lead biomagnification in invertebrate predators from laboratory and field experiments

    International Nuclear Information System (INIS)

    Rubio-Franchini, Isidoro; Rico-Martinez, Roberto

    2011-01-01

    This report includes atomic absorption data from water column, elutriates and zooplankton that demonstrate that lead biomagnifies at El Niagara reservoir, Mexico. Results include field data (bioaccumulation factors) (BAFs) and laboratory data (bioconcentration factors) (BCFs). Two findings: high BAFs for invertebrate predator like Acanthocyclops robustus, Asplanchna brightwellii, Culex sp. larvae, and Hyalella azteca, compared to grazer species Moina micrura and Simocephalus vetulus; low BCF's found for some predators, suggested that lead biomagnifications were taking place. The presence of Moina micrura in the gut of Asplanchna allowed us to design experiments where A. brightwellii was fed lead-exposed M. micrura neonates. The BAF of Asplanchna was 123,684, BCF was 490. Asplanchna individuals fed exposed Moina had 13.31 times more lead than Asplanchna individuals just exposed 48-h to lead, confirming that lead biomagnification occurs. Results of two fish species showed no lead biomagnification, suggesting that lead biomagnification might be restricted to invertebrate predators. - Highlights: → Study shows lead biomagnification evidence in reservoirs where top predators are invertebrates. → Study discusses why in previous studies lead biomagnifications were not detected. → Evidence of biomagnification comes from field and laboratory studies. - This study shows evidence (from field and laboratory experiments) of lead biomagnification in a freshwater reservoir where the main predators are invertebrates.

  1. X-Ray Diffraction of Intermetallic Compounds: A Physical Chemistry Laboratory Experiment

    Science.gov (United States)

    Varberg, Thomas D.; Skakuj, Kacper

    2015-01-01

    Here we describe an experiment for the undergraduate physical chemistry laboratory in which students synthesize the intermetallic compounds AlNi and AlNi3 and study them by X-ray diffractometry. The compounds are synthesized in a simple one-step reaction occurring in the solid state. Powder X-ray diffractograms are recorded for the two compounds…

  2. Database of full-scale laboratory experiments on wave-driven sand transport processes

    NARCIS (Netherlands)

    van der Werf, Jebbe J.; Schretlen, Johanna Lidwina Maria; Ribberink, Jan S.; O'Donoghue, Tom

    2009-01-01

    A new database of laboratory experiments involving sand transport processes over horizontal, mobile sand beds under full-scale non-breaking wave and non-breaking wave-plus-current conditions is described. The database contains details of the flow and bed conditions, information on which quantities

  3. Group as social microcosm: Within-group interpersonal style is congruent with outside group relational tendencies.

    Science.gov (United States)

    Goldberg, Simon B; Hoyt, William T

    2015-06-01

    The notion that individuals' interpersonal behaviors in the context of therapy reflects their interpersonal behaviors outside of therapy is a fundamental hypothesis underlying numerous systems of psychotherapy. The social microcosm hypothesis, in particular, claims the interpersonal therapy group becomes a reflection of group members' general tendencies, and can thus be used as information about members' interpersonal functioning as well as an opportunity for learning and behavior change. The current study tested this hypothesis using data drawn from 207 individuals participating in 22 interpersonal process groups. Ratings were made on 2 key interpersonal domains (Dominance and Affiliation) at baseline and at Weeks 2, 5, and 8 of the group. Two-level multilevel models (with participants nested within groups) were used to account for the hierarchical structure, and the social relations model (SRM; Kenny, 1994) was used to estimate peer ratings (target effects in SRM) unconfounded with rater bias. Participants showed consensus at all time points during the interpersonal process groups on one another's levels of dominance and affiliation. In addition, self- and peer ratings were stable across time and correlated with one another. Importantly, self-ratings made prior to group significantly predicted ratings (self- and peer) made within the group, with effect sizes within the medium range. Taken together, these results provide robust support for the social microcosm hypothesis and the conjecture that interpersonal style within-group therapy is reflective of broader interpersonal tendencies. (c) 2015 APA, all rights reserved).

  4. Dissipation of 2,4-D in soils of the Humid Pampa region, Argentina: a microcosm study.

    Science.gov (United States)

    Merini, Luciano J; Cuadrado, Virginia; Flocco, Cecilia G; Giulietti, Ana M

    2007-06-01

    Phenoxy herbicides like 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in agricultural practices. Although its half life in soil is 7-14d, the herbicide itself and its first metabolite 2,4-dichlorophenol (2,4-DCP) could remain in the soil for longer periods, as a consequence of its intensive use. Microcosms assays were conducted to study the influence of indigenous microflora and plants (alfalfa) on the dissipation of 2,4-D from soils of the Humid Pampa region, Argentina, with previous history of phenoxy herbicides application. Results showed that 2,4-D was rapidly degraded, and the permanence of 2,4-DCP in soil depended on the presence of plants and soil microorganisms. Regarding soil microbial community, the presence of 2,4-D degrading bacteria was detected even in basal conditions in this soil, possibly due to the adaptation of the microflora to the herbicide. There was an increment of two orders of magnitude in herbicide degraders after 15d from 2,4-D addition, both in planted and unplanted microcosms. Total heterotrophic bacteria numbers were about 1x10(8) CFUg(-1) dry soil and no significant differences were found between different treatments. Overall, the information provided by this work indicates that the soil under study has an important intrinsic degradation capacity, given by a microbial community adapted to the presence of phenoxy herbicides.

  5. Laboratory simulation of the formation of an ionospheric depletion using Keda Space Plasma EXperiment (KSPEX

    Directory of Open Access Journals (Sweden)

    Pengcheng Yu

    2017-10-01

    Full Text Available In the work, the formation of an ionospheric depletion was simulated in a controlled laboratory plasma. The experiment was performed by releasing chemical substance sulfur hexafluoride (SF6 into the pure argon discharge plasma. Results indicate that the plasma parameters change significantly after release of chemicals. The electron density is nearly depleted due to the sulfur hexafluoride-electron attachment reaction; and the electron temperature and space potential experience an increase due to the decrease of the electron density. Compared to the traditional active release experiments, the laboratory scheme can be more efficient, high repetition rate and simpler measurement of the varying plasma parameter after chemical releasing. Therefore, it can effective building the bridge between the theoretical work and real space observation.

  6. Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments

    Science.gov (United States)

    Oswald, Sandro M.; Pietsch, Helga; Baumgartner, Dietmar J.; Weihs, Philipp; Rieder, Harald E.

    2017-03-01

    This study investigates the effects of ambient meteorology on the accuracy of radiation (R) measurements performed with pyranometers contained in various heating and ventilation systems (HV-systems). It focuses particularly on instrument offsets observed following precipitation events. To quantify pyranometer responses to precipitation, a series of controlled laboratory experiments as well as two targeted field campaigns were performed in 2016. The results indicate that precipitation (as simulated by spray tests or observed under ambient conditions) significantly affects the thermal environment of the instruments and thus their stability. Statistical analyses of laboratory experiments showed that precipitation triggers zero offsets of -4 W m-2 or more, independent of the HV-system. Similar offsets were observed in field experiments under ambient environmental conditions, indicating a clear exceedance of BSRN (Baseline Surface Radiation Network) targets following precipitation events. All pyranometers required substantial time to return to their initial signal states after the simulated precipitation events. Therefore, for BSRN-class measurements, the recommendation would be to flag the radiation measurements during a natural precipitation event and 90 min after it in nighttime conditions. Further daytime experiments show pyranometer offsets of 50 W m-2 or more in comparison to the reference system. As they show a substantially faster recovery, the recommendation would be to flag the radiation measurements within a natural precipitation event and 10 min after it in daytime conditions.

  7. Experimental terrestrial soil-core microcosm test protocol. A method for measuring the potential ecological effects, fate, and transport of chemicals in terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Van Voris, P.; Tolle, D.A.; Arthur, M.F.

    1985-06-01

    In order to protect the environment properly and have a realistic appraisal of how a chemical will act in the environment, tests of ecological effects and chemical fate must be performed on complex assemblages of biotic and abiotic components (i.e., microcosms) as well as single species. This protocol is one which could be added to a series of tests recently developed as guidelines for Section 4 of the Toxic Substances Control Act (P.L. 94-469; U.S.C., Section 2601-2629). The terrestrial soil-core microcosm is designed to supply site-specific and possibly regional information on the probable chemical fate and ecological effects resulting from release of a chemical substance to a terrestrial ecosystem. The EPA will use the data resulting from this test system to compare the potential hazards of a chemical with others that have been previously evaluated.

  8. Design of simulated nuclear electronics laboratory experiments based on IAEA-TECDOC-530 on pcs

    International Nuclear Information System (INIS)

    Ghousia, S.F.; Nadeem, M.; Khaleeq, M.T.

    2002-05-01

    In this IAEA project, PK-11089 (Design of Simulated Nuclear Electronics Laboratory Experiments based on IAEA-TECDOC-530 on PCs), a software package consisting of Computer-Simulated Laboratory Experiments on Nuclear Electronics compatible with the IAEA-TECDOC-530 (Nuclear Electronics Laboratory Manual) has been developed in OrCAD 9.0 (an electronic circuit simulation software environment) as a self-training aid. The software process model employed in this project is the Feedback Waterfall model with some Rapid Application Model. The project work is completed in the five phases of the SDLC, (all of them have been fully completed) which includes the Requirement Definition, Phase, System and Software Design, Implementation and Unit testing, Integration and System-testing phase and the Operation and Maintenance phase. A total of 125 circuits are designed in 39 experiments from Power Supplies, Analog circuits, Digital circuits and Multi-channel analyzer sections. There is another set of schematic designs present in the package, which contains faulty circuits. This set is designed for the learners to exercise the troubleshooting. The integration and system-testing phase was carried out simultaneously. The Operation and Maintenance phase has been implemented by accomplishing it through some trainees and some undergraduate engineering students by allowing them to play with the software independently. (author)

  9. Laboratory experiments inform iceberg-calving forces

    Science.gov (United States)

    Cathles, L. M.; Burton, J. C.

    2013-12-01

    Globally detected glacial earthquakes are produced during cubic-kilometer scale calving events. The mechanism producing these earthquakes and the dependence of the seismic moment on iceberg size and glacial calving front geometry are not well established. We use a laboratory-scale model of the post-fracture calving process to measure aspects of the calving process not observable in nature. In our experiments, buoyant plastic blocks rest against against a force plate (glacial terminus) which measures both the total force and the torque exerted during the calving process. The blocks are gravitationally unstable, so that they will spontaneously capsize and rotate away from the terminus. We find that hydrodynamics are crucial when considering the coupling between the calving process and the solid earth. There is both a pushing contact force and a simultaneous pulling hydrodynamic force created by a reduced pressure along the terminus face. This suggests that a single couple force mechanism is a more appropriate mode for glacial earthquakes than the commonly used centroid single force model.

  10. The impact of different proportions of a treated effluent on the biotransformation of selected micro-contaminants in river water microcosms.

    Science.gov (United States)

    Nödler, Karsten; Tsakiri, Maria; Licha, Tobias

    2014-10-10

    Attenuation of micro-contaminants is a very complex field in environmental science and evidence suggests that biodegradation rates of micro-contaminants in the aqueous environment depend on the water matrix. The focus of the study presented here is the systematic comparison of biotransformation rates of caffeine, carbamazepine, metoprolol, paracetamol and valsartan in river water microcosms spiked with different proportions of treated effluent (0%, 0.1%, 1%, and 10%). Biotransformation was identified as the dominating attenuation process by the evolution of biotransformation products such as atenolol acid and valsartan acid. Significantly decreasing biotransformation rates of metoprolol were observed at treated effluent proportions ≥ 0.1% whereas significantly increasing biotransformation rates of caffeine and valsartan were observed in the presence of 10% treated effluent. Potential reasons for the observations are discussed and the addition of adapted microorganisms via the treated effluent was suggested as the most probable reason. The impact of additional phosphorus on the biodegradation rates was tested and the experiments revealed that phosphorus-limitation was not responsible.

  11. Educational laboratory experiments on chemistry in a nuclear engineering school

    International Nuclear Information System (INIS)

    Akatsu, E.

    1982-01-01

    An educational laboratory experiment on radiochemistry was investigated by students in the general course of the Nuclear Engineering School of Japan Atomic Energy Research Institute. Most of them are not chemical engineers, but electrical and mechanical engineers. Therefore, the educational experiment was designed for them by introducing a ''word experiment'' in the initial stage and by reducing the chemical procedure as far as possible. It began with calculations on a simple solvent extraction process-the ''word experiment''--followed by the chemical separation of 144 Pr from 144 Ce with tri-n-butyl phosphate in a nitric acid system and then measurement of the radioactive decay and growth of the separated 144 Pr and 144 Ce, respectively. The chemical procedure was explained by the phenomenon but not by the mechanism of chelation. Most students thought the experiment was an exercise in solvent extraction or radiochemical separation rather than a radioactive equilibrium experiment. However, a pure chemist considered it as a sort of physical experiment, where the chemical procedure was used only for preparation of measuring samples. Another experiment, where 137 Cs was measured after isolation with ammonium phosphomolybdate, was also investigated. The experiment eliminated the need for students who were not chemists to know how to use radioactive tracers. These students appreciated the realization that they could understand the radioactivity in the environmental samples in a chemical frame of reference even though they were not chemists

  12. Comparison of laboratory and field experience of PWSCC in Alloy 182 weld metal

    Energy Technology Data Exchange (ETDEWEB)

    Scott, P.; Meunier, M.-C.; Steltzlen, F. [AREVA NP, Tour AREVA, Paris La Defense (France); Calonne, O.; Foucault, M. [AREVA NP, Centre Technique, Le Creusot Cedex (France); Combrade, P. [ACXCOR, Saint Etienne (France); Amzallag, C. [EDF, SEPTEN, Villeurbanne (France)

    2007-07-01

    Laboratory studies of stress corrosion cracking of the nickel base weld metal, Alloy 182, in simulated PWR primary water suggest similar resistance to crack initiation and somewhat enhanced propagation rates relative to wrought Alloy 600. By contrast, field experience of cracking in the primary circuits of PWRs shows in general much better performance for Alloy 182 relative to Alloy 600 than would be anticipated from laboratory studies. This paper endeavours to resolve this apparent conundrum. It draws on the conclusions of recent research that has focussed on the role of surface finish, particularly cold work and residual stresses resulting from different fabrication processes, on the risk of initiating IGSCC in nickel base alloys in PWR primary water. It also draws on field experience of stress corrosion cracking that highlights the important role of surface finish for crack initiation. (author)

  13. Program of experiments for the operating phase of the Underground Research Laboratory

    International Nuclear Information System (INIS)

    Simmons, G.R.; Bilinsky, D.M.; Davison, C.C.; Gray, M.N.; Kjartanson, B.H.; Martin, C.D.; Peters, D.A.; Lang, P.A.

    1992-09-01

    The Underground Research Laboratory (URL) is one of the major research and development facilities that AECL Research has constructed in support of the Canadian Nuclear Fuel Waste Management Program. The URL is a unique geotechnical research facility constructed in previously undisturbed plutonic rock, which was well characterized before construction. The site evaluation and construction phases of the URL project have been completed and the operating phase is beginning. A program of operating phase experiments that address AECL's objectives for in situ testing has been selected. These experiments were subjected to an external peer review and a subsequent review by the URL Experiment Committee in 1989. The comments from the external peer review were incorporated into the experiment plans, and the revised experiments were accepted by the URL Experiment Committee. Summaries of both reviews are presented. The schedule for implementing the experiments and the quality assurance to be applied during implementation are also summarized. (Author) (9 refs., 11 figs.)

  14. Antiseptics and microcosm biofilm formation on titanium surfaces

    Directory of Open Access Journals (Sweden)

    Georgia VERARDI

    2016-01-01

    Full Text Available Abstract Oral rehabilitation with osseointegrated implants is a way to restore esthetics and masticatory function in edentulous patients, but bacterial colonization around the implants may lead to mucositis or peri-implantitis and consequent implant loss. Peri-implantitis is the main complication of oral rehabilitation with dental implants and, therefore, it is necessary to take into account the potential effects of antiseptics such as chlorhexidine (CHX, chloramine T (CHT, triclosan (TRI, and essential oils (EO on bacterial adhesion and on biofilm formation. To assess the action of these substances, we used the microcosm technique, in which the oral environment and periodontal conditions are simulated in vitro on titanium discs with different surface treatments (smooth surface - SS, acid-etched smooth surface - AESS, sand-blasted surface - SBS, and sand-blasted and acid-etched surface - SBAES. Roughness measurements yielded the following results: SS: 0.47 µm, AESS: 0.43 µm, SB: 0.79 µm, and SBAES: 0.72 µm. There was statistical difference only between SBS and AESS. There was no statistical difference among antiseptic treatments. However, EO and CHT showed lower bacterial counts compared with the saline solution treatment (control group. Thus, the current gold standard (CHX did not outperform CHT and EO, which were efficient in reducing the biofilm biomass compared with saline solution.

  15. Evaluation of Surface Runoff Generation Processes Using a Rainfall Simulator: A Small Scale Laboratory Experiment

    Science.gov (United States)

    Danáčová, Michaela; Valent, Peter; Výleta, Roman

    2017-12-01

    Nowadays, rainfall simulators are being used by many researchers in field or laboratory experiments. The main objective of most of these experiments is to better understand the underlying runoff generation processes, and to use the results in the process of calibration and validation of hydrological models. Many research groups have assembled their own rainfall simulators, which comply with their understanding of rainfall processes, and the requirements of their experiments. Most often, the existing rainfall simulators differ mainly in the size of the irrigated area, and the way they generate rain drops. They can be characterized by the accuracy, with which they produce a rainfall of a given intensity, the size of the irrigated area, and the rain drop generating mechanism. Rainfall simulation experiments can provide valuable information about the genesis of surface runoff, infiltration of water into soil and rainfall erodibility. Apart from the impact of physical properties of soil, its moisture and compaction on the generation of surface runoff and the amount of eroded particles, some studies also investigate the impact of vegetation cover of the whole area of interest. In this study, the rainfall simulator was used to simulate the impact of the slope gradient of the irrigated area on the amount of generated runoff and sediment yield. In order to eliminate the impact of external factors and to improve the reproducibility of the initial conditions, the experiments were conducted in laboratory conditions. The laboratory experiments were carried out using a commercial rainfall simulator, which was connected to an external peristaltic pump. The pump maintained a constant and adjustable inflow of water, which enabled to overcome the maximum volume of simulated precipitation of 2.3 l, given by the construction of the rainfall simulator, while maintaining constant characteristics of the simulated precipitation. In this study a 12-minute rainfall with a constant intensity

  16. Local knowledge, environmental politics, and the founding of ecology in the United States. Stephen Forbes and "The Lake as a Microcosm" (1887).

    Science.gov (United States)

    Schneider, D W

    2000-12-01

    Stephen Forbes's "The Lake as a Microcosm" is one of the founding documents of the science of ecology in the United States. By tracing the connections between scientists and local fishermen underlying the research on floodplain lakes presented in "The Lake as a Microcosm," this essay shows how the birth of ecology was tied to local knowledge and the local politics of environmental transformation. Forbes and the other scientists of the Illinois Natural History Survey relied on fishermen for manual labor, expertise in catching fish, and knowledge of the natural history of the fishes. As Forbes and his colleagues worked in close contact with fishermen, they also adopted many of their political concerns over the privatization of the floodplain and became politically active in supporting their interests. The close connection between scientists and local knowledge forced the ecologists to reframe the boundaries of ecology as objective or political, pure or applied, local or scientific.

  17. Upcycling CERN Exhibitions

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    Summer is coming - and with it, a new Microcosm exhibition showcasing CERN (see here). But while the new exhibit is preparing to enchant visitors, many have been asking about the site's former content. Will it simply be out with the old and in with the new? Not as such!   The plasma ball from Microcosm is now on display at the LHCb site. As Microcosm's new content is moving in, its old content is moving up. From LHCb to IdeaSquare, former Microcosm displays and objects are being installed across the CERN site. "Microcosm featured many elements that were well suited to life outside of the exhibition," says Emma Sanders, Microcosm project leader in the EDU group. "We didn't want this popular content to go to waste, and so set out to find them new homes across CERN." The LHCb experiment has received a number of Microcosm favourites, including the Rutherford experiment, the cosmic ray display and the Thomson experiment. "We&...

  18. Evaluation of the biodegradation of Alaska North Slope oil in microcosms using the biodegradation model BIOB

    Directory of Open Access Journals (Sweden)

    Jagadish eTorlapati

    2014-05-01

    Full Text Available We present the details of a numerical model, BIOB that is capable of simulating the biodegradation of oil entrapped in the sediment. The model uses Monod kinetics to simulate the growth of bacteria in the presence of nutrients and the subsequent consumption of hydrocarbons. The model was used to simulate experimental results of Exxon Valdez oil biodegradation in laboratory columns (Venosa et al. (2010. In that study, samples were collected from three different islands: Eleanor Island (EL107, Knight Island (KN114A, and Smith Island (SM006B, and placed in laboratory microcosms for a duration of 168 days to investigate oil bioremediation through natural attenuation and nutrient amendment. The kinetic parameters of the BIOB model were estimated by fitting to the experimental data using a parameter estimation tool based on Genetic Algorithms (GA. The parameter values of EL107 and KN114A were similar whereas those of SM006B were different from the two other sites; in particular biomass growth at SM006B was four times slower than at the other two islands. Grain size analysis from each site revealed that the specific surface area per unit mass of sediment was considerably lower at SM006B, which suggest that the surface area of sediments is a key control parameter for microbial growth in sediments. Comparison of the BIOB results with exponential decay curves fitted to the data indicated that BIOB provided better fit for KN114A and SM006B in nutrient amended treatments, and for EL107 and KN114A in natural attenuation. In particular, BIOB was able to capture the initial slow biodegradation due to the lag phase in microbial growth. Sensitivity analyses revealed that oil biodegradation at all three locations were sensitive to nutrient concentration whereas SM006B was sensitive to initial biomass concentration due to its slow growth rate. Analyses were also performed to compare the half-lives of individual compounds with the decay rate of the overall PAH.

  19. Validation experiment of a numerically processed millimeter-wave interferometer in a laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kogi, Y., E-mail: kogi@fit.ac.jp; Higashi, T.; Matsukawa, S. [Department of Information Electronics, Fukuoka Institute of Technology, Fukuoka 811-0295 (Japan); Mase, A. [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga, Fukuoka 816-0811 (Japan); Kohagura, J.; Yoshikawa, M. [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Nagayama, Y.; Kawahata, K. [National Institute for Fusion Science, Toki, Gifu 509-5202 (Japan); Kuwahara, D. [Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2014-11-15

    We propose a new interferometer system for density profile measurements. This system produces multiple measurement chords by a leaky-wave antenna driven by multiple frequency inputs. The proposed system was validated in laboratory evaluation experiments. We confirmed that the interferometer generates a clear image of a Teflon plate as well as the phase shift corresponding to the plate thickness. In another experiment, we confirmed that quasi-optical mirrors can produce multiple measurement chords; however, the finite spot size of the probe beam degrades the sharpness of the resulting image.

  20. Undergraduate Laboratory Experiment: Measuring Matter Antimatter Asymmetries at the Large Hadron Collider

    CERN Document Server

    Parkes, Chris; Gutierrez, J

    2015-01-01

    This document is the student manual for a third year undergraduate laboratory experiment at the University of Manchester. This project aims to measure a fundamental difference between the behaviour of matter and antimatter through the analysis of data collected by the LHCb experiment at the Large Hadron Collider. The three-body dmecays $B^\\pm \\rightarrow h^\\pm h^+ h^-$, where $h^\\pm$ is a $\\pi^\\pm$ or $K^\\pm$ are studied. The inclusive matter antimatter asymmetry is calculated, and larger asymmetries are searched for in localized regions of the phase-space.

  1. Connecting Solubility, Equilibrium, and Periodicity in a Green, Inquiry Experiment for the General Chemistry Laboratory

    Science.gov (United States)

    Cacciatore, Kristen L.; Amado, Jose; Evans, Jason J.; Sevian, Hannah

    2008-01-01

    We present a novel first-year chemistry laboratory experiment that connects solubility, equilibrium, and chemical periodicity concepts. It employs a unique format that asks students to replicate experiments described in different sample lab reports, each lacking some essential information, rather than follow a scripted procedure. This structure is…

  2. Sebastien Pelletier explains states of matter to an enthusiastic group of youngsters during the opening of a new exhibition in Microcosm last week

    CERN Multimedia

    2000-01-01

    The Fun with Physics workshop will be offered to all 13-14 year olds in school groups visiting CERN this year. The new Microcosm contents have been developed in collaboration with the local teaching community, and cover particles and the forces that act between them.

  3. Performance of the In Situ Microcosm Technique for Measuring the Degradation of Organic Chemicals in Aquifers

    DEFF Research Database (Denmark)

    Nielsen, Per H.; Christensen, Thomas Højlund; Albrechtsen, Hans-Jørgen

    1996-01-01

    chemicals in polluted and pristine aquifers representing different redox environments. The ISM technique has great potential for providing field-relevant degradation potentials and rate constants, but care must be taken in using the equipment and interpreting the results. This paper provides details......An in situ microcosm (ISM) consists of a stainless steel cylinder isolating about 2 L of the aquifer and is equipped with valves allowing for loading and sampling from the ground surface. During the last five years, this technique has been used frequently to study the degradation of organic...

  4. Emulation-Based Virtual Laboratories: A Low-Cost Alternative to Physical Experiments in Control Engineering Education

    Science.gov (United States)

    Goodwin, G. C.; Medioli, A. M.; Sher, W.; Vlacic, L. B.; Welsh, J. S.

    2011-01-01

    This paper argues the case for emulation-based virtual laboratories in control engineering education. It demonstrates that such emulation experiments can give students an industrially relevant educational experience at relatively low cost. The paper also describes a particular emulation-based system that has been developed with the aim of giving…

  5. Transitioning from Expository Laboratory Experiments to Course-Based Undergraduate Research in General Chemistry

    Science.gov (United States)

    Clark, Ted M.; Ricciardo, Rebecca; Weaver, Tyler

    2016-01-01

    General chemistry courses predominantly use expository experiments that shape student expectations of what a laboratory activity entails. Shifting within a semester to course-based undergraduate research activities that include greater decision-making, collaborative work, and "messy" real-world data necessitates a change in student…

  6. Experience of TLD personnel monitoring laboratory

    International Nuclear Information System (INIS)

    Jakhete, Prashant

    2002-01-01

    Full text: Renentech Laboratories is the first Private Enterprise in India to have been chosen to provide Personnel radiation monitoring services to radiation workers at different parts of the country. Since 1992 the Company has been manufacturing TLD phosphor powder of requisite quality and from 1995 commenced the production of TLD cards for radiation monitoring. After getting the necessary approval from the competent authorities in the country, the company undertook a rigorous quality assurance programme and received the accreditation in 1999 to carry out the personnel monitoring of radiation. Since then the trained staff of the Company is covering 1200 institutions in 16 states where radiation is being used. This translates to processing of 60,000 Till cards annually, the maximum limit permitted by BARC. Processing of exposure data is done strictly according well-laid guidelines. Any cases of overexposure are immediately referred to Calibration and Dose Record Section of BARC to meet the regulatory requirements. Necessary procedural guidelines are followed to handle such cases. In this lecture, learning, operation and implementation experience of a typical Private Company in a task, which, hitherto had been regarded as exclusive responsibility of state owned institution, is enumerated

  7. Ice and Atoms: experiments with laboratory-based positron beams

    International Nuclear Information System (INIS)

    Coleman, P G

    2011-01-01

    This short review presents results of new positron and positronium (Ps) experiments in condensed matter and atomic physics, as an illustration of the satisfying variety of scientific endeavours involving positron beams which can be pursued with relatively simple apparatus in a university laboratory environment. The first of these two studies - on ice films - is an example of how positrons and Ps can provide new insights into an important system which has been widely interrogated by other techniques. The second is an example of how simple positron beam systems can still provide interesting information - here on a current interesting fundamental problem in positron atomic physics.

  8. Solid deuterated water in space: detection constraints from laboratory experiments

    Science.gov (United States)

    Urso, R. G.; Palumbo, M. E.; Baratta, G. A.; Scirè, C.; Strazzulla, G.

    2018-06-01

    The comparison between astronomical spectra and laboratory experiments is fundamental to spread light on the structure and composition of ices found in interstellar dense molecular clouds and in Solar System bodies. Water is among the most abundant solid-phase species observed in these environments, and several attempts have been made to investigate the presence of its solid-phase isotopologues. In particular, the detection of the O-D stretching mode band at 4.1 μm due to both D2O and HDO within icy grain mantles is still under debate, and no detection have been reported about the presence of these species within icy bodies in the Solar System yet. In the near future, an important contribution could derive from the data acquired in the O-D stretching mode spectral range by the sensitive instruments on board the James Webb Space Telescope. With this in mind, we performed several laboratory experiments to study the O-D stretching mode band in solid mixtures containing water and deuterated water deposited in the temperature range between 17 and 155 K, in order to simulate astrophysical relevant conditions. Furthermore, samples have been studied at various temperature and irradiated with energetic ions (200 keV H+) in order to study the effects induced by both thermal and energetic processing. Our results provide some constraints on the detection of the 4.1 μm band in astronomical environments.

  9. Constraints on the rheology of the partially molten mantle from numerical models of laboratory experiments

    Science.gov (United States)

    Rudge, J. F.; Alisic Jewell, L.; Rhebergen, S.; Katz, R. F.; Wells, G. N.

    2015-12-01

    One of the fundamental components in any dynamical model of melt transport is the rheology of partially molten rock. This rheology is poorly understood, and one way in which a better understanding can be obtained is by comparing the results of laboratory deformation experiments to numerical models. Here we present a comparison between numerical models and the laboratory setup of Qi et al. 2013 (EPSL), where a cylinder of partially molten rock containing rigid spherical inclusions was placed under torsion. We have replicated this setup in a finite element model which solves the partial differential equations describing the mechanical process of compaction. These computationally-demanding 3D simulations are only possible due to the recent development of a new preconditioning method for the equations of magma dynamics. The experiments show a distinct pattern of melt-rich and melt-depleted regions around the inclusions. In our numerical models, the pattern of melt varies with key rheological parameters, such as the ratio of bulk to shear viscosity, and the porosity- and strain-rate-dependence of the shear viscosity. These observed melt patterns therefore have the potential to constrain rheological properties. While there are many similarities between the experiments and the numerical models, there are also important differences, which highlight the need for better models of the physics of two-phase mantle/magma dynamics. In particular, the laboratory experiments display more pervasive melt-rich bands than is seen in our numerics.

  10. Insights into environmental controls on microbial communities in a continental serpentinite aquifer using a microcosm-based approach.

    Science.gov (United States)

    Crespo-Medina, Melitza; Twing, Katrina I; Kubo, Michael D Y; Hoehler, Tori M; Cardace, Dawn; McCollom, Tom; Schrenk, Matthew O

    2014-01-01

    Geochemical reactions associated with serpentinization alter the composition of dissolved organic compounds in circulating fluids and potentially liberate mantle-derived carbon and reducing power to support subsurface microbial communities. Previous studies have identified Betaproteobacteria from the order Burkholderiales and bacteria from the order Clostridiales as key components of the serpentinite-hosted microbiome, however there is limited knowledge of their metabolic capabilities or growth characteristics. In an effort to better characterize microbial communities, their metabolism, and factors limiting their activities, microcosm experiments were designed with fluids collected from several monitoring wells at the Coast Range Ophiolite Microbial Observatory (CROMO) in northern California during expeditions in March and August 2013. The incubations were initiated with a hydrogen atmosphere and a variety of carbon sources (carbon dioxide, methane, acetate, and formate), with and without the addition of nutrients and electron acceptors. Growth was monitored by direct microscopic counts; DNA yield and community composition was assessed at the end of the 3 month incubation. For the most part, results indicate that bacterial growth was favored by the addition of acetate and methane, and that the addition of nutrients and electron acceptors had no significant effect on microbial growth, suggesting no nutrient- or oxidant-limitation. However, the addition of sulfur amendments led to different community compositions. The dominant organisms at the end of the incubations were closely related to Dethiobacter sp. and to the family Comamonadaceae, which are also prominent in culture-independent gene sequencing surveys. These experiments provide one of first insights into the biogeochemical dynamics of the serpentinite subsurface environment and will facilitate experiments to trace microbial activities in serpentinizing ecosystems.

  11. Operational experience at RCD and FCD laboratories during various ventilation conditions

    International Nuclear Information System (INIS)

    Murali, S.; Ashok Kumar, P.; Thanamani, M.; Rath, D.P.; Sapkal, J.A.; Raman, Anand

    2007-01-01

    Radiochemistry and Fuel Chemistry wing of Radiological Laboratory facility has various radio-chemical operations on isotopes of plutonium and trans-plutonium elements, carried out under containment and safe operational conditions. The ventilation provided to the facility is a Once - through system. The ventilation system is designed with separate headers for laboratory and glove box exhausts. There is scheduled periodic shut down of ventilation system for maintenance during non-occupancy hours/week ends. The buildup of natural α - emitters activity due to ventilation shut down, observed to be prevailing on stack air sample filter papers after the ventilation startup, is studied. The paper describes the operational experience gained over a period during ventilation shut down and suggests the course of remedial action for reducing the internal exposure due to build up of natural α - emitters and their progenies. (author)

  12. The effects of plant diversity on nitrous oxide emissions in hydroponic microcosms

    Science.gov (United States)

    Sun, Hongying; Zhang, Chongbang; Song, Changchun; Chang, Scott X.; Gu, Baojing; Chen, Zhengxin; Peng, Changhui; Chang, Jie; Ge, Ying

    2013-10-01

    Previous studies have shown that plant diversity can improve the wastewater purification efficiency of constructed wetlands (CWs), but its effect on the nitrous oxide (N2O) emission in CWs has been unknown. To investigate the effect of plant diversity on the N2O emission, we established four plant species richness levels (each level containing 1, 2, 3 and 4 species, respectively) by using 96 hydroponic microcosms. Results showed that plant species richness enhanced the N2O emission, ranging from 27.1 to 115.4 μg N2O m-2 d-1, and improved nitrate removal (P 0.05), but improved nitrogen removal (P < 0.001). Hence, our study highlights the importance of both plant species richness and species identity in mediating the N2O emission and nitrogen removal in CWs.

  13. Low-cost nonlinear optics experiment for undergraduate instructional laboratory and lecture demonstration

    Science.gov (United States)

    Turchiello, Rozane de F.; Pereira, Luiz A. A.; Gómez, Sergio L.

    2017-07-01

    This paper presents a simple and affordable experiment on the thermal lens effect, suitable for an undergraduate educational laboratory or as a tabletop demonstration in a lecture on nonlinear optics. Such an experiment exploits the formation of a lens in an absorbing medium illuminated by a laser beam with a Gaussian intensity profile. As an absorber, we use a commercial soy sauce, which exhibits a strong thermal lensing effect. Additionally, we show how to measure the radius of a Gaussian beam using the knife-edge method, and how to estimate the focal length of the induced thermal lens.

  14. Field tracer transport experiments at the site of Canada's underground research laboratory

    International Nuclear Information System (INIS)

    Frost, L.H.; Davison, C.C.; Vandergraaf, T.T.; Scheier, N.W.; Kozak, E.T.

    1997-01-01

    To gain a better understanding of the processes affecting solute transport in fractured crystalline rock, groundwater tracer experiments are being performed within natural fracture domains and excavation damage zones at various scales at the site of AECL's Underground Research Laboratory (URL). The main objective of these experiments is to develop and demonstrate methods for characterizing the solute transport properties within fractured crystalline rock. Estimates of these properties are in turn being used in AECL's conceptual and numerical models of groundwater flow and solute transport through the geosphere surrounding a nuclear fuel waste disposal vault in plutonic rock of the Canadian Shield. (author)

  15. A Wideband Magnetoresistive Sensor for Monitoring Dynamic Fault Slip in Laboratory Fault Friction Experiments.

    Science.gov (United States)

    Kilgore, Brian D

    2017-12-02

    A non-contact, wideband method of sensing dynamic fault slip in laboratory geophysical experiments employs an inexpensive magnetoresistive sensor, a small neodymium rare earth magnet, and user built application-specific wideband signal conditioning. The magnetoresistive sensor generates a voltage proportional to the changing angles of magnetic flux lines, generated by differential motion or rotation of the near-by magnet, through the sensor. The performance of an array of these sensors compares favorably to other conventional position sensing methods employed at multiple locations along a 2 m long × 0.4 m deep laboratory strike-slip fault. For these magnetoresistive sensors, the lack of resonance signals commonly encountered with cantilever-type position sensor mounting, the wide band response (DC to ≈ 100 kHz) that exceeds the capabilities of many traditional position sensors, and the small space required on the sample, make them attractive options for capturing high speed fault slip measurements in these laboratory experiments. An unanticipated observation of this study is the apparent sensitivity of this sensor to high frequency electomagnetic signals associated with fault rupture and (or) rupture propagation, which may offer new insights into the physics of earthquake faulting.

  16. A Stopped-Flow Kinetics Experiment for the Physical Chemistry Laboratory Using Noncorrosive Reagents

    Science.gov (United States)

    Prigodich, Richard V.

    2014-01-01

    Stopped-flow kinetics techniques are important to the study of rapid chemical and biochemical reactions. Incorporation of a stopped-flow kinetics experiment into the physical chemistry laboratory curriculum would therefore be an instructive addition. However, the usual reactions studied in such exercises employ a corrosive reagent that can over…

  17. Ground-Laboratory to In-Space Atomic Oxygen Correlation for the Polymer Erosion and Contamination Experiment (PEACE) Polymers

    Science.gov (United States)

    Stambler, Arielle H.; Inoshita, Karen E.; Roberts, Lily M.; Barbagallo, Claire E.; deGroh, Kim K.; Banks, Bruce A.

    2011-01-01

    The Materials International Space Station Experiment 2 (MISSE 2) Polymer Erosion and Contamination Experiment (PEACE) polymers were exposed to the environment of low Earth orbit (LEO) for 3.95 years from 2001 to 2005. There were 41 different PEACE polymers, which were flown on the exterior of the International Space Station (ISS) in order to determine their atomic oxygen erosion yields. In LEO, atomic oxygen is an environmental durability threat, particularly for long duration mission exposures. Although spaceflight experiments, such as the MISSE 2 PEACE experiment, are ideal for determining LEO environmental durability of spacecraft materials, ground-laboratory testing is often relied upon for durability evaluation and prediction. Unfortunately, significant differences exist between LEO atomic oxygen exposure and atomic oxygen exposure in ground-laboratory facilities. These differences include variations in species, energies, thermal exposures and radiation exposures, all of which may result in different reactions and erosion rates. In an effort to improve the accuracy of ground-based durability testing, ground-laboratory to in-space atomic oxygen correlation experiments have been conducted. In these tests, the atomic oxygen erosion yields of the PEACE polymers were determined relative to Kapton H using a radio-frequency (RF) plasma asher (operated on air). The asher erosion yields were compared to the MISSE 2 PEACE erosion yields to determine the correlation between erosion rates in the two environments. This paper provides a summary of the MISSE 2 PEACE experiment; it reviews the specific polymers tested as well as the techniques used to determine erosion yield in the asher, and it provides a correlation between the space and ground laboratory erosion yield values. Using the PEACE polymers asher to in-space erosion yield ratios will allow more accurate in-space materials performance predictions to be made based on plasma asher durability evaluation.

  18. Competitive outcome of Daphnia-Simocephalus experimental microcosms: salinity versus priority effects.

    Directory of Open Access Journals (Sweden)

    Cláudia Loureiro

    Full Text Available Competition is a major driving force in freshwaters, especially given the cyclic nature and dynamics of pelagic food webs. Competition is especially important in the initial species assortment during colonization and re-colonization events, which depends strongly on the environmental context. Subtle changes, such as saline intrusion, may disrupt competitive relationships and, thus, influence community composition. Bearing this in mind, our objective was to assess whether low salinity levels (using NaCl as a proxy alter the competitive outcome (measured as the rate of population biomass increase of Daphnia-Simocephalus experimental microcosms, taking into account interactions with priority effects (sequential species arrival order. With this approach, we aimed to experimentally demonstrate a putative mechanism of differential species sorting in brackish environments or in freshwaters facing secondary salinization. Experiments considered three salinity levels, regarding NaCl added (0.00, 0.75 and 1.50 g L(-1, crossed with three competition scenarios (no priority, priority of Daphnia over Simocephalus, and vice-versa. At lower NaCl concentrations (0.00 and 0.75 g L(-1, Daphnia was a significantly superior competitor, irrespective of the species inoculation order, suggesting negligible priority effects. However, the strong decrease in Daphnia population growth at 1.50 g L(-1 alleviated the competitive pressure on Simocephalus, causing an inversion of the competitive outcome in favour of Simocephalus. The intensity of this inversion depended on the competition scenario. This salinity-mediated disruption of the competitive outcome demonstrates that subtle environmental changes produce indirect effects in key ecological mechanisms, thus altering community composition, which may lead to serious implications in terms of ecosystem functioning (e.g. lake regime shifts due to reduced grazing and biodiversity.

  19. Radon transport in fractured soil. Laboratory experiments and modelling

    International Nuclear Information System (INIS)

    Hoff, A.

    1997-10-01

    Radon (Rn-222) transport in fractured soil has been investigated by laboratory experiments and by modelling. Radon transport experiments have been performed with two sand columns (homogeneous and inhomogeneous) and one undisturbed clayey till column containing a net of preferential flow paths (root holes). A numerical model (the finite-element model FRACTRAN) and an analytic model (a pinhole model) have been applied in simulations if soil gas and radon transport in fractured soil. Experiments and model calculations are included in a discussion of radon entry rates into houses placed on fractured soil. The main conclusion is, that fractures does not in general alter transport of internally generated radon out of soil, when the pressure and flow conditions in the soil is comparable to the conditions prevailing under a house. This indicates the important result, that fractures in soil have no impact on radon entry into a house beyond that of an increased gas permeability, but a more thorough investigation of this subject is needed. Only in the case where the soil is exposed to large pressure gradients, relative to gradients induced by a house, may it be possible to observe effects of radon exchange between fractures and matrix. (au) 52 tabs., 60 ill., 5 refs

  20. Radon transport in fractured soil. Laboratory experiments and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, A

    1997-10-01

    Radon (Rn-222) transport in fractured soil has been investigated by laboratory experiments and by modelling. Radon transport experiments have been performed with two sand columns (homogeneous and inhomogeneous) and one undisturbed clayey till column containing a net of preferential flow paths (root holes). A numerical model (the finite-element model FRACTRAN) and an analytic model (a pinhole model) have been applied in simulations if soil gas and radon transport in fractured soil. Experiments and model calculations are included in a discussion of radon entry rates into houses placed on fractured soil. The main conclusion is, that fractures does not in general alter transport of internally generated radon out of soil, when the pressure and flow conditions in the soil is comparable to the conditions prevailing under a house. This indicates the important result, that fractures in soil have no impact on radon entry into a house beyond that of an increased gas permeability, but a more thorough investigation of this subject is needed. Only in the case where the soil is exposed to large pressure gradients, relative to gradients induced by a house, may it be possible to observe effects of radon exchange between fractures and matrix. (au) 52 tabs., 60 ill., 5 refs.

  1. Imidazole as a pH Probe: An NMR Experiment for the General Chemistry Laboratory

    Science.gov (United States)

    Hagan, William J., Jr.; Edie, Dennis L.; Cooley, Linda B.

    2007-01-01

    The analysis describes an NMR experiment for the general chemistry laboratory, which employs an unknown imidazole solution to measure the pH values. The described mechanism can also be used for measuring the acidity within the isolated cells.

  2. [Explore microcosmic connection between autophagy mechanism and follicular development based on "kidney governing reproduction" theory].

    Science.gov (United States)

    Bai, Jun; Wu, Ke-Ming; Gao, Ran-Ran

    2018-03-01

    In the theory of traditional Chinese medicine(TCM) that "kidney storing essence and governing reproduction", reproductive essence is an important part of the kidney essence and acts as the original material of offspring embryos. Sperm, oocyte and zygote should be all included in the range of reproductive essence. Ovum is the essence of reproduction from inborn. The follicles maturation depends on the quality of oocyte and the vigor of kidney essence. Meanwhile, discharge of mature ovum relies on the stimulation and promotion by kidney Qi. Autophagy almost exists in different cells stages and all various of mammalian cells. Many studies have found that autophagy not only participates in the formation of follicles, but also in every phase of the follicles development, and is involved in the occurrence and development of ovarian diseases. Recently, more and more scholars believe that autophagy is a new field to explore the microcosmic relationship between autophagy and TCM. Kidney-nourishing TCM could promote follicular growth and improve variety clinical symptoms by inhibiting the apoptosis of ovarian granulosa cells and reducing follicular atresia. Meanwhile, apoptosis of ovarian granulosa cells is closely related to autophagy of ovarian granulosa cells. In order to provide some theoretical foundation for kidney-nourishing therapy's promoting effect on follicular growth and improving effect on ovarian function, also to further explore the molecular mechanism of kidney-nourishing medicine in promoting follicular development, this paper would explain the microcosmic relationship between autophagy and follicular development based on the theory of "kidney governing reproduction". All of these would be of great significance to prevent and intervene the diseases of reproductive system timely and effectively. Copyright© by the Chinese Pharmaceutical Association.

  3. The testing effect for mediator final test cues and related final test cues in online and laboratory experiments.

    Science.gov (United States)

    Coppens, Leonora C; Verkoeijen, Peter P J L; Bouwmeester, Samantha; Rikers, Remy M J P

    2016-05-31

    The testing effect is the finding that information that is retrieved during learning is more often correctly retrieved on a final test than information that is restudied. According to the semantic mediator hypothesis the testing effect arises because retrieval practice of cue-target pairs (mother-child) activates semantically related mediators (father) more than restudying. Hence, the mediator-target (father-child) association should be stronger for retrieved than restudied pairs. Indeed, Carpenter (2011) found a larger testing effect when participants received mediators (father) than when they received target-related words (birth) as final test cues. The present study started as an attempt to test an alternative account of Carpenter's results. However, it turned into a series of conceptual (Experiment 1) and direct (Experiment 2 and 3) replications conducted with online samples. The results of these online replications were compared with those of similar existing laboratory experiments through small-scale meta-analyses. The results showed that (1) the magnitude of the raw mediator testing effect advantage is comparable for online and laboratory experiments, (2) in both online and laboratory experiments the magnitude of the raw mediator testing effect advantage is smaller than in Carpenter's original experiment, and (3) the testing effect for related cues varies considerably between online experiments. The variability in the testing effect for related cues in online experiments could point toward moderators of the related cue short-term testing effect. The raw mediator testing effect advantage is smaller than in Carpenter's original experiment.

  4. Immersion and contact freezing experiments in the Mainz wind tunnel laboratory

    Science.gov (United States)

    Eppers, Oliver; Mayer, Amelie; Diehl, Karoline; Mitra, Subir; Borrmann, Stephan; Szakáll, Miklós

    2016-04-01

    Immersion and contact freezing are of outmost important ice nucleation processes in mixed phase clouds. Experimental studies are carried out in the Mainz vertical wind tunnel laboratory in order to characterize these nucleation processes for different ice nucleating particles (INP), such as for mineral dust or biological particles. Immersion freezing is investigated in our laboratory with two different experimental techniques, both attaining contact-free levitation of liquid droplets and cooling of the surrounding air down to about -25 °C. In an acoustic levitator placed in the cold room of our laboratory, drops with diameters of 2 mm are investigated. In the vertical air stream of the wind tunnel droplets with diameter of 700 micron are freely floated at their terminal velocities, simulating the flow conditions of the free atmosphere. Furthermore, the wind tunnel offers a unique platform for contact freezing experiments. Supercooled water droplets are floated in the vertical air stream at their terminal velocities and INP are injected into the tunnel air stream upstream of them. As soon as INP collides with the supercooled droplet the contact freezing is initiated. The first results of immersion and contact freezing experiments with cellulose particles both in the acoustic levitator and in the wind tunnel will be presented. Cellulose is considered as typical INP of biological origin and a macrotracer for plant debris. Nucleating properties of cellulose will be provided, mainly focusing on the temperature, INP concentration, and specific surface area dependences of the freezing processes. Direct comparison between the different experimental techniques (acoustic levitator and wind tunnel), as well as between nucleation modes (immersion and contact freezing) will be presented. The work is carried out within the framework of the German research unit INUIT.

  5. Diffusion Experiments with Opalinus and Callovo-Oxfordian Clays: Laboratory, Large-Scale Experiments and Microscale Analysis by RBS

    International Nuclear Information System (INIS)

    Garcia-Gutierrez, M.; Alonso, U.; Missana, T.; Cormenzana, J.L.; Mingarro, M.; Morejon, J.; Gil, P.

    2009-01-01

    Consolidated clays are potential host rocks for deep geological repositories for high-level radioactive waste. Diffusion is the main transport process for radionuclides (RN) in these clays. Radionuclide (RN) diffusion coefficients are the most important parameters for Performance Assessment (PA) calculations of clay barriers. Different diffusion methodologies were applied at a laboratory scale to analyse the diffusion behaviour of a wide range of RN. Main aims were to understand the transport properties of different RNs in two different clays and to contribute with feasible methodologies to improve in-situ diffusion experiments, using samples of larger scale. Classical laboratory essays and a novel experimental set-up for large-scale diffusion experiments were performed, together to a novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS), for diffusion analyses at the micrometer scale. The main experimental and theoretical characteristics of the different methodologies, and their advantages and limitations are here discussed. Experiments were performed with the Opalinus and the Callovo-Oxfordian clays. Both clays are studied as potential host rock for a repository. Effective diffusion coefficients ranged between 1.10 - 10 to 1.10 - 12 m 2 /s for neutral, low sorbing cations (as Na and Sr) and anions. Apparent diffusion coefficients for strongly sorbing elements, as Cs and Co, are in the order of 1.10-13 m 2 /s; europium present the lowest diffusion coefficient (5.10 - 15 m 2 /s). The results obtained by the different approaches gave a comprehensive database of diffusion coefficients for RN with different transport behaviour within both clays. (Author) 42 refs

  6. Effect of moisture and temperature variation on DOC release from a peatland: conflicting results from laboratory, field and historical data analysis.

    Science.gov (United States)

    Preston, Michael D; Eimers, M Catherine; Watmough, Shaun A

    2011-03-01

    Peatlands are large repositories of atmospheric carbon and concern has been raised over the stability of this carbon store because increasing dissolved organic carbon (DOC) concentrations have been observed in peatland drainage waters. A number of potential causes have been proposed in the literature, and conflicting results among studies conducted at different spatial and temporal scales suggest that the methodological approach may be an important confounding factor. The objective of this study was to determine the influence of moisture and temperature on DOC release from a south-central Ontario peatland during the fall (a major export period) following three commonly used approaches: laboratory microcosms, an intensive field study and analysis of long-term data (1980-2008). The effect of variations in temperature and moisture differed among microcosm, field study and analysis of the long-term record. Water content was important at the microcosm scale as DOC concentration and aromaticity increased with peat water-saturation. Drought caused a decrease in DOC concentration and pH, and an increase in sulphate and base cation concentrations. In contrast, the field study indicated that DOC concentration was strongly associated with temperature, and weakly correlated (negatively) with stream discharge. Average fall DOC concentration (but not export) increased over the 29 year record, and was correlated with fall discharge and precipitation (negative) and summer precipitation and fall stream pH (positive). As no common strong predictor of fall DOC was found at three scales of investigation at a single, well-studied site, it may be unreasonable to expect to identify a universal driver behind the widespread increase in DOC concentration. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. Role of Laboratory Plasma Experiments in exploring the Physics of Solar Eruptions

    Science.gov (United States)

    Tripathi, S.

    2017-12-01

    Solar eruptive events are triggered over a broad range of spatio-temporal scales by a variety of fundamental processes (e.g., force-imbalance, magnetic-reconnection, electrical-current driven instabilities) associated with arched magnetoplasma structures in the solar atmosphere. Contemporary research on solar eruptive events is at the forefront of solar and heliospheric physics due to its relevance to space weather. Details on the formation of magnetized plasma structures on the Sun, storage of magnetic energy in such structures over a long period (several Alfven transit times), and their impulsive eruptions have been recorded in numerous observations and simulated in computer models. Inherent limitations of space observations and uncontrolled nature of solar eruptions pose significant challenges in testing theoretical models and developing the predictive capability for space-weather. The pace of scientific progress in this area can be significantly boosted by tapping the potential of appropriately scaled laboratory plasma experiments to compliment solar observations, theoretical models, and computer simulations. To give an example, recent results from a laboratory plasma experiment on arched magnetic flux ropes will be presented and future challenges will be discussed. (Work supported by National Science Foundation, USA under award number 1619551)

  8. Small Laccase from "Streptomyces Coelicolor"--An Ideal Model Protein/Enzyme for Undergraduate Laboratory Experience

    Science.gov (United States)

    Cook, Ryan; Hannon, Drew; Southard, Jonathan N.; Majumdar, Sudipta

    2018-01-01

    A one semester undergraduate biochemistry laboratory experience is described for an understanding of recombinant technology from gene cloning to protein characterization. An integrated experimental design includes three sequential modules: molecular cloning, protein expression and purification, and protein analysis and characterization. Students…

  9. Five biomedical experiments flown in an Earth orbiting laboratory: Lessons learned from developing these experiments on the first international microgravity mission from concept to landing

    Science.gov (United States)

    Winget, C. M.; Lashbrook, J. J.; Callahan, P. X.; Schaefer, R. L.

    1993-01-01

    There are numerous problems associated with accommodating complex biological systems in microgravity in the flexible laboratory systems installed in the Orbiter cargo bay. This presentation will focus upon some of the lessons learned along the way from the University laboratory to the IML-1 Microgravity Laboratory. The First International Microgravity Laboratory (IML-1) mission contained a large number of specimens, including: 72 million nematodes, US-1; 3 billion yeast cells, US-2; 32 million mouse limb-bud cells, US-3; and 540 oat seeds (96 planted), FOTRAN. All five of the experiments had to undergo significant redevelopment effort in order to allow the investigator's ideas and objectives to be accommodated within the constraints of the IML-1 mission. Each of these experiments were proposed as unique entities rather than part of the mission, and many procedures had to be modified from the laboratory practice to meet IML-1 constraints. After a proposal is accepted by NASA for definition, an interactive process is begun between the Principal Investigator and the developer to ensure a maximum science return. The success of the five SLSPO-managed experiments was the result of successful completion of all preflight biological testing and hardware verification finalized at the KSC Life Sciences Support Facility housed in Hangar L. The ESTEC Biorack facility housed three U.S. experiments (US-1, US-2, and US-3). The U.S. Gravitational Plant Physiology Facility housed GTHRES and FOTRAN. The IML-1 mission (launched from KSC on 22 Jan. 1992, and landed at Dryden Flight Research Facility on 30 Jan. 1992) was an outstanding success--close to 100 percent of the prelaunch anticipated science return was achieved and, in some cases, greater than 100 percent was achieved (because of an extra mission day).

  10. Influence of trenbolone on the structural and functional diversity of microbial communities from a lake sediment

    OpenAIRE

    Radl, Viviane

    2006-01-01

    In recent years, substances with endocrine-disrupting activity have been detected in aquatic ecosystems worldwide. Application of sewage biosolids, dung or manure with high hormone concentrations onto agricultural land are one import source of contamination. Although effects of endocrine-disrupting chemicals on vertebrates have been deeply investigated, less is known about their interactions with non-target organisms, e.g. microorganisms. In microcosms experiments (outdoor and laboratory) usi...

  11. Applicability of sorption data determined by laboratory experiments for evaluation of strontium-85 mobility in subsurface field

    International Nuclear Information System (INIS)

    Tanaka, Tadao; Mukai, Masayuki

    2003-01-01

    Applicability of laboratory measurements to radionuclide transport in a natural environment was studied using the data from the field tests. The K d values obtained in the laboratory experiments were input into the instantaneous equilibrium sorption model, which simulates the migration of 85 Sr in the unsaturated loess. This simulation managed to reproduce results of the aforementioned field tests. To evaluate more accurately migration behavior of 85 Sr, based on the sorption data obtained by the laboratory experiments, the hybrid sorption model consisting of the equilibrium sorption process and the kinetic sorption process was proposed. When compared with predictions using the K d -based equilibrium sorption model, the results of the field migration tests of 85 Sr were more successfully reproduced by introducing the hybrid sorption model. (author)

  12. Laboratory Experiments in Physics for Modern Astronomy With Comprehensive Development of the Physical Principles

    CERN Document Server

    Golden, Leslie

    2013-01-01

    This book presents experiments which will teach physics relevant to astronomy. The astronomer, as instructor, frequently faces this need when his college or university has no astronomy department and any astronomy course is taught in the physics department. The physicist, as instructor, will find this intellectually appealing when faced with teaching an introductory astronomy course. From these experiments, the student will acquire important analytical tools, learn physics appropriate to astronomy, and experience instrument calibration and the direct gathering and analysis of data. Experiments that can be performed in one laboratory session as well as semester-long observation projects are included. This textbook is aimed at undergraduate astronomy students.

  13. Effects of pH upon the environmental fate of [14C]fenitrothion in an aquatic microcosm

    International Nuclear Information System (INIS)

    Fisher, S.W.

    1985-01-01

    The environmental fate of [ 14 C]fenitrothion was evaluated in aquatic microcosms held at pH 8.3 or 6.7. No general effect attributable to pH was observed; however, several significant interactions were identified. Of these, the findings that statistically higher amounts of radioactivity were present in water held at pH 6.7 and that significantly less metabolism of the parent compound occurred in the organisms at pH 8.3 were preeminent. These differences seen in metabolism and environmental fate between pH values are relatively minor and do not compromise the safety of the compound

  14. Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments

    OpenAIRE

    S. M. Oswald; H. Pietsch; D. J. Baumgartner; P. Weihs; H. E. Rieder

    2017-01-01

    This study investigates effects of ambient meteorology on the accuracy of radiation measurements performed with pyranometers contained in various heating/ventilation systems (HV-systems). It focuses particularly on instrument offsets observed following precipitation events. To quantify pyranometer responses to precipitation, a series of controlled laboratory experiments as well as two targeted field campaigns were performed in 2016. The results indicate that precipitation (as simulated by spr...

  15. In situ and laboratory migration experiments through boom clay at Mol

    International Nuclear Information System (INIS)

    Preter, P. de; Put, M.; Canniere, P. de

    1993-01-01

    Physico-chemical characterization and migration studies in the Boom clay, envisaged as a potential host sediment for high level waste disposal in Belgium, were started some 15 years ago. A synthesis study of this experimental work has recently been conducted to compile all available data. From a comparison of the available migration data and the data requirements as derived from the performance assessment studies PAGIS (1988) and PACOMA (1991) the new migration programme (1991-1995) was defined. The critical radionuclides, both with relation to dose rates to man and to missing or unreliable migration data, turned out to be 14 C, 99 Tc. 135 Cs and 237 Np. A second group of radionuclides was found to be possibly critical: 79 Se, 93 Zr, 107 Pd, U - , Am - , Cm - , and Pu-isotopes. This report concentrates on the experimental results as obtained from the migration experiments started in the previous migration programme. Some of the reported radionuclides e.g. 90 Sr) have lost their critical character and will not be further studied within the new programme. New experimental data from laboratory tests have become available for Np, Cs, Sr and C (as HC0 3 - ) and the first results on the migration of organic molecules dissolved in the interstitial Boom clay water are reported. The hydraulic parameters (the hydraulic conductivity K and the storage coefficient S o ) were calculated from both laboratory percolation experiments and in situ piezometric measurements. Conclusions concerning Boom clay anisotropy are drawn. Finally, a short description of the ongoing in situ HTO injection experiment is given and the experimental data are analyzed and discussed. 10 refs., 4 figs., 1 tab

  16. Linear Accelerator Laboratory

    International Nuclear Information System (INIS)

    1976-01-01

    This report covers the activity of the Linear Accelerator Laboratory during the period June 1974-June 1976. The activity of the Laboratory is essentially centered on high energy physics. The main activities were: experiments performed with the colliding rings (ACO), construction of the new colliding rings and beginning of the work at higher energy (DCI), bubble chamber experiments with the CERN PS neutrino beam, counter experiments with CERN's PS and setting-up of equipment for new experiments with CERN's SPS. During this period a project has also been prepared for an experiment with the new PETRA colliding ring at Hamburg. On the other hand, intense collaboration with the LURE Laboratory, using the electron synchrotron radiation emitted by ACO and DCI, has been developed [fr

  17. Interactive virtual optical laboratories

    Science.gov (United States)

    Liu, Xuan; Yang, Yi

    2017-08-01

    Laboratory experiences are essential for optics education. However, college students have limited access to advanced optical equipment that is generally expensive and complicated. Hence there is a need for innovative solutions to expose students to advanced optics laboratories. Here we describe a novel approach, interactive virtual optical laboratory (IVOL) that allows unlimited number of students to participate the lab session remotely through internet, to improve laboratory education in photonics. Although students are not physically conducting the experiment, IVOL is designed to engage students, by actively involving students in the decision making process throughout the experiment.

  18. EXPERIENCE OF THE ORGANIZATION OF VIRTUAL LABORATORIES ON THE BASIS OF TECHNOLOGIES OF CLOUD COMPUTING

    Directory of Open Access Journals (Sweden)

    V. Oleksyuk

    2014-06-01

    Full Text Available The article investigated the concept of «virtual laboratory». This paper describes models of deploying of cloud technologies in IT infrastructure. The hybrid model is most recent for higher educational institution. The author suggests private cloud platforms to deploying the virtual laboratory. This paper describes the experience of the deployment enterprise cloud in IT infrastructure of Department of Physics and Mathematics of Ternopil V. Hnatyuk National Pedagogical University. The object of the research are virtual laboratories as components of IT infrastructure of higher education. The subject of the research are clouds as base of deployment of the virtual laboratories. Conclusions. The use of cloud technologies in the development virtual laboratories of the is an actual and need of the development. The hybrid model is the most appropriate in the deployment of cloud infrastructure of higher educational institution. It is reasonable to use the private (Cloudstack, Eucalyptus, OpenStack cloud platform in the universities.

  19. Effects of non-steroidal anti-inflammatory drugs on cyanobacteria and algae in laboratory strains and in natural algal assemblages.

    Science.gov (United States)

    Bácsi, István; B-Béres, Viktória; Kókai, Zsuzsanna; Gonda, Sándor; Novák, Zoltán; Nagy, Sándor Alex; Vasas, Gábor

    2016-05-01

    In recent years measurable concentrations of non-steroidal anti-inflammatory drugs (NSAIDs) have been shown in the aquatic environment as a result of increasing human consumption. Effects of five frequently used non-steroidal anti-inflammatory drugs (diclofenac, diflunisal, ibuprofen, mefenamic acid and piroxicam in 0.1 mg ml(-1) concentration) in batch cultures of cyanobacteria (Synechococcus elongatus, Microcystis aeruginosa, Cylindrospermopsis raciborskii), and eukaryotic algae (Desmodesmus communis, Haematococcus pluvialis, Cryptomonas ovata) were studied. Furthermore, the effects of the same concentrations of NSAIDs were investigated in natural algal assemblages in microcosms. According to the changes of chlorophyll-a content, unicellular cyanobacteria seemed to be more tolerant to NSAIDs than eukaryotic algae in laboratory experiments. Growth of eukaryotic algae was reduced by all drugs, the cryptomonad C. ovata was the most sensitive to NSAIDs, while the flagellated green alga H. pluvialis was more sensitive than the non-motile green alga D. communis. NSAID treatments had weaker impact in the natural assemblages dominated by cyanobacteria than in the ones dominated by eukaryotic algae, confirming the results of laboratory experiments. Diversity and number of functional groups did not change notably in cyanobacteria dominated assemblages, while they decreased significantly in eukaryotic algae dominated ones compared to controls. The results highlight that cyanobacteria (especially unicellular ones) are less sensitive to the studied, mostly hardly degradable NSAIDs, which suggest that their accumulation in water bodies may contribute to the expansion of cyanobacterial mass productions in appropriate environmental circumstances by pushing back eukaryotic algae. Thus, these contaminants require special attention during wastewater treatment and monitoring of surface waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. A Laboratory experiment on vermicomposting of winery residues and sewage sledge

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, M. D.; Molina, M. J.; Llinares, J.; Pons, V.; Pallares, L.

    2009-07-01

    Organic waste addition to agricultural soils is proposed as a disposal strategy to improve the structural properties and organic matter content of soils. In this work, the results obtained after a vermicomposting process are reported. The process has been performed mixing rabitt crop wastes with increasing addition of either vinasse bio solids or municipal sewage sludges. For this purpose, a laboratory experiment was conducted in which both wastes were inoculated with earthworms (Eisenia foetida) and maintained under controlled conditions for 4 months. (Author)

  1. A Laboratory experiment on vermicomposting of winery residues and sewage sledge

    International Nuclear Information System (INIS)

    Soriano, M. D.; Molina, M. J.; Llinares, J.; Pons, V.; Pallares, L.

    2009-01-01

    Organic waste addition to agricultural soils is proposed as a disposal strategy to improve the structural properties and organic matter content of soils. In this work, the results obtained after a vermicomposting process are reported. The process has been performed mixing rabitt crop wastes with increasing addition of either vinasse bio solids or municipal sewage sludges. For this purpose, a laboratory experiment was conducted in which both wastes were inoculated with earthworms (Eisenia foetida) and maintained under controlled conditions for 4 months. (Author)

  2. In-situ subaqueous capping of mercury-contaminated sediments in a fresh-water aquatic system, Part I—Bench-scale microcosm study to assess methylmercury production

    International Nuclear Information System (INIS)

    Randall, Paul M.; Fimmen, Ryan; Lal, Vivek; Darlington, Ramona

    2013-01-01

    Bench-scale microcosm experiments were designed to provide a better understanding of the potential for Hg methylation in sediments from an aquatic environment. Experiments were conducted to examine the function of sulfate concentration, lactate concentration, the presence/absence of an aqueous inorganic Hg spike, and the presence/absence of inoculums of Desulfovibrio desulfuricans, a strain of sulfate-reducing bacteria (SRB) commonly found in the natural sediments of aquatic environments. Incubations were analyzed for both the rate and extent of (methylmercury) MeHg production. Methylation rates were estimated by analyzing MeHg and Hg after 2, 7, 14, 28, and 42 days. The production of metabolic byproducts, including dissolved gases as a proxy for metabolic utilization of carbon substrate, was also monitored. In all treatments amended with lactate, sulfate, Hg, and SRB, MeHg was produced (37 ng/g-sediment dry weight) after only 48 h of incubation and reached a maximum sediment concentration of 127 ng/g-sediment dry weight after the 42 day incubation period. Aqueous phase production of MeHg was observed to be 10 ng/L after 2 day, reaching a maximum observed concentration of 32.8 ng/L after 14 days, and declining to 10.8 ng/L at the end of the incubation period (42 day). The results of this study further demonstrates that, in the presence of an organic carbon substrate, sulfate, and the appropriate consortia of microorganisms, sedimentary Hg will be transformed into MeHg through bacterial metabolism. Further, this study provided the basis for evaluation of an in-situ subaqueous capping strategy that may limit (or potentially enhance) MeHg production. -- Highlights: • Hg methylation by SRB is limited by the depletion of sulfate and carbon. • Hg methylation is sensitive to competition by methanogens for carbon substrate. • In high lactate environment, all lactate was utilized in the microcosms within seven days. • In the absence of adequate metabolic fuel, Me

  3. In-situ subaqueous capping of mercury-contaminated sediments in a fresh-water aquatic system, Part I—Bench-scale microcosm study to assess methylmercury production

    Energy Technology Data Exchange (ETDEWEB)

    Randall, Paul M., E-mail: randall.paul@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States); Fimmen, Ryan [Geosyntec Consultants, 150 E. Wilson Bridge Road, Suite 232, Worthington, OH 43085 (United States); Lal, Vivek; Darlington, Ramona [Battelle, 505 King Ave., Columbus, OH 43201 (United States)

    2013-08-15

    Bench-scale microcosm experiments were designed to provide a better understanding of the potential for Hg methylation in sediments from an aquatic environment. Experiments were conducted to examine the function of sulfate concentration, lactate concentration, the presence/absence of an aqueous inorganic Hg spike, and the presence/absence of inoculums of Desulfovibrio desulfuricans, a strain of sulfate-reducing bacteria (SRB) commonly found in the natural sediments of aquatic environments. Incubations were analyzed for both the rate and extent of (methylmercury) MeHg production. Methylation rates were estimated by analyzing MeHg and Hg after 2, 7, 14, 28, and 42 days. The production of metabolic byproducts, including dissolved gases as a proxy for metabolic utilization of carbon substrate, was also monitored. In all treatments amended with lactate, sulfate, Hg, and SRB, MeHg was produced (37 ng/g-sediment dry weight) after only 48 h of incubation and reached a maximum sediment concentration of 127 ng/g-sediment dry weight after the 42 day incubation period. Aqueous phase production of MeHg was observed to be 10 ng/L after 2 day, reaching a maximum observed concentration of 32.8 ng/L after 14 days, and declining to 10.8 ng/L at the end of the incubation period (42 day). The results of this study further demonstrates that, in the presence of an organic carbon substrate, sulfate, and the appropriate consortia of microorganisms, sedimentary Hg will be transformed into MeHg through bacterial metabolism. Further, this study provided the basis for evaluation of an in-situ subaqueous capping strategy that may limit (or potentially enhance) MeHg production. -- Highlights: • Hg methylation by SRB is limited by the depletion of sulfate and carbon. • Hg methylation is sensitive to competition by methanogens for carbon substrate. • In high lactate environment, all lactate was utilized in the microcosms within seven days. • In the absence of adequate metabolic fuel, Me

  4. A Survey on Faculty Perspectives on the Transition to a Biochemistry Course-Based Undergraduate Research Experience Laboratory

    Science.gov (United States)

    Craig, Paul A.

    2017-01-01

    It will always remain a goal of an undergraduate biochemistry laboratory course to engage students hands-on in a wide range of biochemistry laboratory experiences. In 2006, our research group initiated a project for "in silico" prediction of enzyme function based only on the 3D coordinates of the more than 3800 proteins "of unknown…

  5. Ranking protective coatings: Laboratory vs. field experience

    Science.gov (United States)

    Conner, Jeffrey A.; Connor, William B.

    1994-12-01

    Environmentally protective coatings are used on a wide range of gas turbine components for survival in the harsh operating conditions of engines. A host of coatings are commercially available to protect hot-section components, ranging from simple aluminides to designer metallic overlays and ceramic thermal barrier coatings. A variety of coating-application processes are available, and they range from simple pack cementation processing to complex physical vapor deposition, which requires multimillion dollar facilities. Detailed databases are available for most coatings and coating/process combinations for a range of laboratory tests. Still, the analysis of components actually used in engines often yields surprises when compared against predicted coating behavior from laboratory testing. This paper highlights recent work to develop new laboratory tests that better simulate engine environments. Comparison of in-flight coating performance as well as industrial and factory engine testing on a range of hardware is presented along with laboratory predictions from standard testing and from recently developed cyclic burner-rig testing.

  6. Nitration of Phenols Using Cu(NO[subscript 3])[subscript 2]: Green Chemistry Laboratory Experiment

    Science.gov (United States)

    Yadav, Urvashi; Mande, Hemant; Ghalsasi, Prasanna

    2012-01-01

    An easy-to-complete, microwave-assisted, green chemistry, electrophilic nitration method for phenol using Cu(NO[subscript 3])[subscript 2] in acetic acid is discussed. With this experiment, students clearly understand the mechanism underlying the nitration reaction in one laboratory session. (Contains 4 schemes.)

  7. If you pay peanuts: a laboratory experiment on reward schemes in employment service contracting

    NARCIS (Netherlands)

    van de Meerendonk, A.; Onderstal, S.

    2010-01-01

    The design of tenders and contracts is a crucial factor in the success or failure of the contracting-out of reintegration services. In a laboratory experiment with professionals from private reintegration service providers, we tested two tender designs. In the first design, the government announces

  8. Fault healing promotes high-frequency earthquakes in laboratory experiments and on natural faults

    Science.gov (United States)

    McLaskey, Gregory C.; Thomas, Amanda M.; Glaser, Steven D.; Nadeau, Robert M.

    2012-01-01

    Faults strengthen or heal with time in stationary contact and this healing may be an essential ingredient for the generation of earthquakes. In the laboratory, healing is thought to be the result of thermally activated mechanisms that weld together micrometre-sized asperity contacts on the fault surface, but the relationship between laboratory measures of fault healing and the seismically observable properties of earthquakes is at present not well defined. Here we report on laboratory experiments and seismological observations that show how the spectral properties of earthquakes vary as a function of fault healing time. In the laboratory, we find that increased healing causes a disproportionately large amount of high-frequency seismic radiation to be produced during fault rupture. We observe a similar connection between earthquake spectra and recurrence time for repeating earthquake sequences on natural faults. Healing rates depend on pressure, temperature and mineralogy, so the connection between seismicity and healing may help to explain recent observations of large megathrust earthquakes which indicate that energetic, high-frequency seismic radiation originates from locations that are distinct from the geodetically inferred locations of large-amplitude fault slip

  9. Designing experiments on thermal interactions by secondary-school students in a simulated laboratory environment

    Science.gov (United States)

    Lefkos, Ioannis; Psillos, Dimitris; Hatzikraniotis, Euripides

    2011-07-01

    Background and purpose: The aim of this study was to explore the effect of investigative activities with manipulations in a virtual laboratory on students' ability to design experiments. Sample Fourteen students in a lower secondary school in Greece attended a teaching sequence on thermal phenomena based on the use of information and communication technology, and specifically of the simulated virtual laboratory 'ThermoLab'. Design and methods A pre-post comparison was applied. Students' design of experiments was rated in eight dimensions; namely, hypothesis forming and verification, selection of variables, initial conditions, device settings, materials and devices used, process and phenomena description. A three-level ranking scheme was employed for the evaluation of students' answers in each dimension. Results A Wilcoxon signed-rank test revealed a statistically significant difference between the students' pre- and post-test scores. Additional analysis by comparing the pre- and post-test scores using the Hake gain showed high gains in all but one dimension, which suggests that this improvement was almost inclusive. Conclusions We consider that our findings support the statement that there was an improvement in students' ability to design experiments.

  10. Diffusion Experiments with Opalinus and Callovo-Oxfordian Clays: Laboratory, Large-Scale Experiments and Microscale Analysis by RBS

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Gutierrez, M.; Alonso, U.; Missana, T.; Cormenzana, J.L.; Mingarro, M.; Morejon, J.; Gil, P.

    2009-09-25

    Consolidated clays are potential host rocks for deep geological repositories for high-level radioactive waste. Diffusion is the main transport process for radionuclides (RN) in these clays. Radionuclide (RN) diffusion coefficients are the most important parameters for Performance Assessment (PA) calculations of clay barriers. Different diffusion methodologies were applied at a laboratory scale to analyse the diffusion behaviour of a wide range of RN. Main aims were to understand the transport properties of different RNs in two different clays and to contribute with feasible methodologies to improve in-situ diffusion experiments, using samples of larger scale. Classical laboratory essays and a novel experimental set-up for large-scale diffusion experiments were performed, together to a novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS), for diffusion analyses at the micrometer scale. The main experimental and theoretical characteristics of the different methodologies, and their advantages and limitations are here discussed. Experiments were performed with the Opalinus and the Callovo-Oxfordian clays. Both clays are studied as potential host rock for a repository. Effective diffusion coefficients ranged between 1.10{sup -}10 to 1.10{sup -}12 m{sup 2}/s for neutral, low sorbing cations (as Na and Sr) and anions. Apparent diffusion coefficients for strongly sorbing elements, as Cs and Co, are in the order of 1.10-13 m{sup 2}/s; europium present the lowest diffusion coefficient (5.10{sup -}15 m{sup 2}/s). The results obtained by the different approaches gave a comprehensive database of diffusion coefficients for RN with different transport behaviour within both clays. (Author) 42 refs.

  11. Influences of aquatic plants on the fate of the pyrethroid insecticide lambda-cyhalothrin in aquatic environments.

    Science.gov (United States)

    Hand, L H; Kuet, S F; Lane, M C; Maund, S J; Warinton, J S; Hill, I R

    2001-08-01

    Aquatic exposure assessments for pesticides are generally based on laboratory studies performed in water alone or water sediment systems. Although aquatic macrophytes, which include a variety of bryophytes, macroalgae, and angiosperms, can be a significant component of many aquatic ecosystems, their impact on pesticide fate is generally not included in exposure assessments. To investigate the influence of aquatic plants on the fate and behavior of the pyrethroid insecticide lambda (lambda)-cyhalothrin, two laboratory experiments (to assess adsorption and degradation) and an indoor microcosm study (to assess fate under semirealistic conditions) were conducted. In the laboratory studies, adsorption to macrophytes was extensive and essentially irreversible, and degradation occurred rapidly by cleavage of the ester bond. In the indoor microcosm, which contained water, sediment, and macrophytes from a pond, degradation was also rapid, with DT50 and DT90 values of less than 3 and 19 h, respectively, for dissipation from the water column and of less than 3 and 56 h, respectively, for the whole system. For adsorptive and readily degraded pesticides like lambda-cyhalothrin, we conclude that macrophytes have considerable influence on fate and behavior in surface waters.

  12. Effects of different levels of UV-B radiation on marine epilithic communities: a short-term microcosm study

    Directory of Open Access Journals (Sweden)

    R. A. Danilov

    2000-12-01

    Full Text Available Epilithic communities from brackish coastal water of the east coast of Sweden were studied in order to reveal their responses to different levels of UV-B radiation. The experiment was conducted for seven days in an indoor microcosm system. The epilithic communities were exposed daily to different doses of UV-B radiation: 1, 3, 5 and 7 hours, respectively. The intensity of the UV-B radiation used was similar to that in natural environments. After seven days clear shifts both in species composition and community structure were observed. All species of diatoms showed negative correlation with enhanced levels of UV-B. On the other hand, abundance of cyanobacteria was positively correlated with enhanced levels of UV-B (Calothrix aeruginea, R=0.49;Oscillatoria amphibia, R=0.93; Pseudanabaena mucicola, R=0.26. Communities dominated by diatoms and green algae at the initial stage of the experiment did show a drastic decrease in diatom abundance under UV-B stress and finally became dominated by cyanobacteria. Among green algae the abundance of Cladophora sericea correlated positively (R=0.33 with enhanced exposure to UV-B, while Monoraphidium-species exhibited negative correlation to UV-B. Otherwise, no significant correlation between other green algae species identified and UV-B stress could be detected. We conclude that UV-B radiation, even at lower levels, is capable to induce severe changes to marine epilithic communities. The trends revealed in the present study predict a shift from communities dominated by diatoms and green algae to those dominated by cyanobacteria.

  13. Genotypic variability enhances the reproducibility of an ecological study.

    Science.gov (United States)

    Milcu, Alexandru; Puga-Freitas, Ruben; Ellison, Aaron M; Blouin, Manuel; Scheu, Stefan; Freschet, Grégoire T; Rose, Laura; Barot, Sebastien; Cesarz, Simone; Eisenhauer, Nico; Girin, Thomas; Assandri, Davide; Bonkowski, Michael; Buchmann, Nina; Butenschoen, Olaf; Devidal, Sebastien; Gleixner, Gerd; Gessler, Arthur; Gigon, Agnès; Greiner, Anna; Grignani, Carlo; Hansart, Amandine; Kayler, Zachary; Lange, Markus; Lata, Jean-Christophe; Le Galliard, Jean-François; Lukac, Martin; Mannerheim, Neringa; Müller, Marina E H; Pando, Anne; Rotter, Paula; Scherer-Lorenzen, Michael; Seyhun, Rahme; Urban-Mead, Katherine; Weigelt, Alexandra; Zavattaro, Laura; Roy, Jacques

    2018-02-01

    Many scientific disciplines are currently experiencing a 'reproducibility crisis' because numerous scientific findings cannot be repeated consistently. A novel but controversial hypothesis postulates that stringent levels of environmental and biotic standardization in experimental studies reduce reproducibility by amplifying the impacts of laboratory-specific environmental factors not accounted for in study designs. A corollary to this hypothesis is that a deliberate introduction of controlled systematic variability (CSV) in experimental designs may lead to increased reproducibility. To test this hypothesis, we had 14 European laboratories run a simple microcosm experiment using grass (Brachypodium distachyon L.) monocultures and grass and legume (Medicago truncatula Gaertn.) mixtures. Each laboratory introduced environmental and genotypic CSV within and among replicated microcosms established in either growth chambers (with stringent control of environmental conditions) or glasshouses (with more variable environmental conditions). The introduction of genotypic CSV led to 18% lower among-laboratory variability in growth chambers, indicating increased reproducibility, but had no significant effect in glasshouses where reproducibility was generally lower. Environmental CSV had little effect on reproducibility. Although there are multiple causes for the 'reproducibility crisis', deliberately including genetic variability may be a simple solution for increasing the reproducibility of ecological studies performed under stringently controlled environmental conditions.

  14. Experiments at the Aespoe Hard Rock Laboratory

    International Nuclear Information System (INIS)

    2004-12-01

    A dress rehearsal is being held in preparation for the construction of a deep repository for spent nuclear fuel at SKB's underground Hard Rock Laboratory (HRL) on Aespoe, outside Oskarshamn. Here we can test different technical solutions on a full scale and in a realistic environment. The Aespoe HRL is also used for field research. We are conducting a number of experiments here in collaboration with Swedish and international experts. In the Zedex experiment we have compared how the rock is affected around a drill-and-blast tunnel versus a bored tunnel. In a new experiment we will investigate how much the rock can take. A narrow pillar between two boreholes will be loaded to the point that the rock's ultimate strength is exceeded (Aespoe Pillar Stability Experiment). In the Demo Test we are demonstrating emplacement of the copper canisters and the surrounding bentonite in the deposition holes. In the Prototype Repository we study what long-term changes occur in the barriers under the conditions prevailing in a deep repository. Horizontal deposition: Is it possible to deposit the canisters horizontally without compromising safety? Backfill and Plug Test: The tunnels in the future deep repository for spent nuclear fuel will be filled with clay and crushed rock and then plugged. Canister Retrieval Test: If the deep repository should not perform satisfactorily for some reason, we want to be able to retrieve the spent fuel. The Lot test is intended to show how the bentonite behaves in an environment similar to that in the future deep repository. The purpose of the TBT test is to determine how the bentonite clay in the buffer is affected by high temperatures. Two-phase flow means that liberated gas in the groundwater flows separately in the fractures in the rock. This reduces the capacity of the rock to conduct water. Lasgit: By pressurizing a canister with helium, we can measure how the gas moves through the surrounding buffer. Colloid Project: Can very small particles

  15. Team-Based Learning, Faculty Research, and Grant Writing Bring Significant Learning Experiences to an Undergraduate Biochemistry Laboratory Course

    Science.gov (United States)

    Evans, Hedeel Guy; Heyl, Deborah L.; Liggit, Peggy

    2016-01-01

    This biochemistry laboratory course was designed to provide significant learning experiences to expose students to different ways of succeeding as scientists in academia and foster development and improvement of their potential and competency as the next generation of investigators. To meet these goals, the laboratory course employs three…

  16. Assessment of agglomeration, co-sedimentation and trophic transfer of titanium dioxide nanoparticles in a laboratory-scale predator-prey model system

    Science.gov (United States)

    Gupta, Govind Sharan; Kumar, Ashutosh; Shanker, Rishi; Dhawan, Alok

    2016-08-01

    Nano titanium dioxide (nTiO2) is the most abundantly released engineered nanomaterial (ENM) in aquatic environments. Therefore, it is prudent to assess its fate and its effects on lower trophic-level organisms in the aquatic food chain. A predator-and-prey-based laboratory microcosm was established using Paramecium caudatum and Escherichia coli to evaluate the effects of nTiO2. The surface interaction of nTiO2 with E. coli significantly increased after the addition of Paramecium into the microcosm. This interaction favoured the hetero-agglomeration and co-sedimentation of nTiO2. The extent of nTiO2 agglomeration under experimental conditions was as follows: combined E. coli and Paramecium > Paramecium only > E. coli only > without E. coli or Paramecium. An increase in nTiO2 internalisation in Paramecium cells was also observed in the presence or absence of E. coli cells. These interactions and nTiO2 internalisation in Paramecium cells induced statistically significant (p < 0.05) effects on growth and the bacterial ingestion rate at 24 h. These findings provide new insights into the fate of nTiO2 in the presence of bacterial-ciliate interactions in the aquatic environment.

  17. Bioremediation of petroleum contaminated soil at CFS Alert - Laboratory scale respirometry experiment

    International Nuclear Information System (INIS)

    Haidar, S.; Bennett, J.; Jarrett, P.; Biggar, K.

    1998-01-01

    The feasibility of 'biopiling' was tested at Canadian Forces Station 'Alert', located in the high Arctic where the feasibility of bioremediation is yet to be proven. Laboratory respirometer experiments were conducted at 11 degrees C that examined the behaviour of indigenous microorganisms. Experiments were also carried out at one contaminated site. Various soil properties were analyzed, as well as total petroleum hydrocarbons. Results showed that the respirometer system functioned properly in monitoring the behaviour of microorganisms, that indigenous microorganisms were active at 11 degrees C, and that they functioned at a constant rate of oxygen consumption. These results suggest that biopiling may be feasible under the conditions existing at CFS 'Alert'. 12 refs., 5 tabs., 8 figs

  18. Contribution of vegetation and water table on isoprene emission from boreal peatland microcosms

    DEFF Research Database (Denmark)

    Tiiva, Päivi; Faubert, Patrick; Räty, Sanna

    2009-01-01

    emission in these naturally wet ecosystems, although water table is predicted to decline due to climate warming. We studied the relative contribution of mosses vs. vascular plants to isoprene emission in boreal peatland microcosms in growth chambers by removing either vascular vegetation or both vascular...... hollows with intact vegetation, 45 ± 6 µg m-2 h-1, was decreased by 25% under water table drawdown. However, water table drawdown reduced net ecosystem carbon dioxide (CO2) exchange more dramatically than isoprene emission. Isoprene emission strongly correlated with both CO2 exchange and methane emission......Boreal peatlands are substantial sources of isoprene, a reactive hydrocarbon. However, it is not known how much mosses, vascular plants and peat each contribute to isoprene emission from peatlands. Furthermore, there is no information on the effects of declining water table depth on isoprene...

  19. Dehydration of 2-Methyl-1-Cyclohexanol: New Findings from a Popular Undergraduate Laboratory Experiment

    Science.gov (United States)

    Friesen, J. Brent; Schretzman, Robert

    2011-01-01

    The mineral acid-catalyzed dehydration of 2-methyl-1-cyclohexanol has been a popular laboratory exercise in second-year organic chemistry for several decades. The dehydration experiment is often performed by organic chemistry students to illustrate Zaitsev's rule. However, sensitive analytical techniques reveal that the results do not entirely…

  20. Nulling interferometry for the darwin mission: laboratory demonstration experiment

    Science.gov (United States)

    Ollivier, Marc; Léger, Alain; Sekulic, Predrag; Labèque, Alain; Michel, Guy

    2017-11-01

    The DARWIN mission is a project of the European Space Agency that should allow around 2012 the search for extrasolar planets and a spectral analysis of their potential atmosphere in order to evidence gases and particularly tracers of life. The principle of the instrument is based on the Bracewell nulling interferometer. It allows high angular resolution and high dynamic range. However, this concept, proposed more than 20 years ago, has never been experimentally demonstrated in the thermal infrared with high levels of extinction. We present here a laboratory monochromatic experiment dedicated to this goal. A theoretical and numerical approach of the question highlights a strong difficulty: the need for very clean and homogeneous wavefronts, in terms of intensity, phase and polarisation distribution. A classical interferometric approach appears to be insufficient to reach our goals. We have shown theoretically then numerically that this difficulty can be surpassed if we perform an optical filtering of the interfering beams. This technique allows us to decrease strongly the optical requirements and to view very high interferometric contrast measurements with commercial optical pieces. We present here a laboratory interferometer working at 10,6 microns, and implementing several techniques of optical filtering (pinholes and single-mode waveguides), its realisation, and its first promising results. We particularly present measurements that exhibit stable visibility levels better than 99,9% that is to say extinction levels better than 1000.

  1. The Effect of an Open-Ended Design Experience on Student Achievement in an Engineering Laboratory Course

    Directory of Open Access Journals (Sweden)

    Matthew Cullin

    2017-11-01

    Full Text Available This study explores the effect of incorporating an Open-Ended Design Experience (OEDE into an undergraduate materials science laboratory taken by third-year mechanical engineering students. The focus of the OEDE was carbon fiber reinforced plastics and sandwich structures. The results indicate that the incorporation of OEDE’s in laboratory courses produces significant benefits in terms of student engagement, participation, and perception of competence. In addition, the OEDE was found to enhance students’ ability to apply related concepts as compared to non-OEDE lab activities. The authors conclude that the incorporation of OEDE’s can increase the effectiveness of engineering laboratory courses.

  2. Fitting It All In: Adapting a Green Chemistry Extraction Experiment for Inclusion in an Undergraduate Analytical Laboratory

    Science.gov (United States)

    Buckley, Heather L.; Beck, Annelise R.; Mulvihill, Martin J.; Douskey, Michelle C.

    2013-01-01

    Several principles of green chemistry are introduced through this experiment designed for use in the undergraduate analytical chemistry laboratory. An established experiment of liquid CO2 extraction of D-limonene has been adapted to include a quantitative analysis by gas chromatography. This facilitates drop-in incorporation of an exciting…

  3. Kinetics of Hydrolysis of Acetic Anhydride by In-Situ FTIR Spectroscopy: An Experiment for the Undergraduate Laboratory

    Science.gov (United States)

    Haji, Shaker; Erkey, Can

    2005-01-01

    A reaction kinetics experiment for the chemical engineering undergraduate laboratory course was developed in which in-situ Fourier Transfer Infrared spectroscopy was used to measure reactant and product concentrations. The kinetics of the hydrolysis of acetic anhydride was determined by experiments carried out in a batch reactor. The results…

  4. Quantum Dots in a Polymer Composite: A Convenient Particle-in-a-Box Laboratory Experiment

    Science.gov (United States)

    Rice, Charles V.; Giffin, Guinevere A.

    2008-01-01

    Semiconductor quantum dots are at the forefront of materials science chemistry with applications in biological imaging and photovoltaic technologies. We have developed a simple laboratory experiment to measure the quantum-dot size from fluorescence spectra. A major roadblock of quantum-dot based exercises is the particle synthesis and handling;…

  5. Performance assessment experience at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Lee, D.W.

    1994-01-01

    The development of a performance assessment (PA) for low-level radioactive waste disposal operations at Oak Ridge National Laboratory (ORNL) was initiated in 1989 and is continuing. A draft PA was prepared in September 1990 and submitted to the DOE Peer Review Panel for review and comment. Recommendations were received that formed the basis for a revised PA that was completed in December 1993. The review of the revised PA is continuing. This paper reviews the experience gained in the preparation of the PA including the technical difficulties associated with performance assessment in Oak Ridge and an overview of the methods used in the PA. Changes in waste operations that resulted from the findings in the PA include improved waste acceptance criteria, waste certification, and waste management practices. The discussion includes issues that relate to the application of current performance objectives to older disposal facilities, which are being addressed as part of the CERCLA process

  6. The effects of nutrient enrichment on oil sands reclaimed wetlands : a field microcosm study

    International Nuclear Information System (INIS)

    Chen, H.; Farwell, A.; Dixon, G.

    2010-01-01

    Bitumen extraction processes generate large amounts of processed materials containing polycyclic aromatic hydrocarbons (PAHs), naphthenic acids (NA), and additional salts. The use of processed materials in reclaimed wetlands and lakes has an impact on aquatic faunal and floral colonization. This study investigated the effects on nutrient enrichment on reclaimed wetlands containing processed materials. Chlorophyll a and total biomass analyses were conducted in order to evaluate the influence of nutrient addition on primary production. The nutrients were added to microcosms with differing levels of fertility for 3 different water types with varying NA concentrations in 3 different reclamation substrates. Results of the study showed different levels of growth depending on both the water and substrate type. Combined planktonic and periphytic growth was highest in water with high levels of dissolved organic and inorganic carbon.

  7. Network Performance and Quality of Experience of Remote Access Laboratories

    Directory of Open Access Journals (Sweden)

    Alexander A. Kist

    2012-11-01

    Full Text Available Remote Access Laboratories (RAL have become important learning and teaching tools. This paper presents a performance study that targets a specific remote access architecture implemented within a universities operational environment. This particular RAL system provides globally authenticated and arbitrated remote access to virtualized computers as well as computer controlled hardware experiments. This paper presents system performance results that have been obtained utilizing both a set of automated and human subject tests. Principle objectives of the study were: To gain a better understanding of the nature of network traffic caused by experimental activity usage; to obtain an indication of user expectations of activity performance; and to develop a measure to predict Quality of Experience, based on easily measurable Quality of Service parameters. The study emulates network layer variation of access-bandwidth and round-trip-time of typical usage scenarios and contrasts against user perception results that allow classifying expected user performance. It demonstrates that failure rate is excellent measure of usability, and that round-trip-time predominantly affects user experience. Thin-client and remote desktop architectures are popular to separate the location of users and the actual data processing and use similar structures, hence results of this study to be applied in these application areas as well.

  8. Synthesis of 10-Ethyl Flavin: A Multistep Synthesis Organic Chemistry Laboratory Experiment for Upper-Division Undergraduate Students

    Science.gov (United States)

    Sichula, Vincent A.

    2015-01-01

    A multistep synthesis of 10-ethyl flavin was developed as an organic chemistry laboratory experiment for upper-division undergraduate students. Students synthesize 10-ethyl flavin as a bright yellow solid via a five-step sequence. The experiment introduces students to various hands-on experimental organic synthetic techniques, such as column…

  9. Laboratory Impact Experiments

    Science.gov (United States)

    Horanyi, M.; Munsat, T.

    2017-12-01

    The experimental and theoretical programs at the SSERVI Institute for Modeling Plasmas, Atmospheres, and Cosmic Dust (IMPACT) address the effects of hypervelocity dust impacts and the nature of the space environment of granular surfaces interacting with solar wind plasma and ultraviolet radiation. These are recognized as fundamental planetary processes due their role in shaping the surfaces of airless planetary objects, their plasma environments, maintaining dust haloes, and sustaining surface bound exospheres. Dust impacts are critically important for all airless bodies considered for possible human missions in the next decade: the Moon, Near Earth Asteroids (NEAs), Phobos, and Deimos, with direct relevance to crew and mission safety and our ability to explore these objects. This talk will describe our newly developed laboratory capabilities to assess the effects of hypervelocity dust impacts on: 1) the gardening and redistribution of dust particles; and 2) the generation of ionized and neutral gasses on the surfaces of airless planetary bodies.

  10. Ready to don a white coat?

    CERN Multimedia

    Anaïs Schaeffer

    2014-01-01

    What better way to learn than to try yourself? That’s the idea of S'Cool LAB, a new teaching laboratory: it offers school-children visiting CERN the chance to take part in a half-day practical workshop in a purpose-equipped lab.   S’Cool LAB’s first pupils testing the new laboratory. Photo: Jeff Wiener. S’Cool LAB, which originated from an idea first suggested about 15 years ago, was launched on 3 July and will start to welcome pupils by early 2015. "This new lab is housed in the lower part of Microcosm, where the UA1* experiment detector was previously on display," explains Jeff Wiener, who led the project to set up S'Cool LAB at the same time as completing his thesis in the field of education. “It’s now known as Building 143-R-003. For more than a year now, we’ve been putting up dividing walls to separate the lab from the rest of Microcosm, and we've fitted it with a smart floor ...

  11. Microbial analysis of the buffer/container experiment at AECL's underground research laboratory

    International Nuclear Information System (INIS)

    Stroes-Gascoyne, S.

    1996-07-01

    The Buffer/Container Experiment (BCE) was carried out at AECL's Underground Research Laboratory (URL) for 2.5 years to examine the in situ performance of compacted buffer material in a single emplacement borehole under vault-relevant conditions. During decommissioning of this experiment, numerous samples were taken for microbial analysis to determine if the naturally present microbial population in buffer material survived the conditions (i.e., compaction, heat and desiccation) in the BCE and to determine which group(s) of microorganisms would be dominant in such a simulated vault environment. Such knowledge will be very useful in assessing the potential effects of microbial activity on the concept for deep disposal of Canada's nuclear fuel waste, proposed by AECL. 46 refs., 31 tabs., 35 figs

  12. HPLC of the Polypeptides in a Hydrolyzate of Egg-White Lysozyme. An Experiment for the Undergraduate Biochemistry Laboratory.

    Science.gov (United States)

    Richardson, W. S., III; Burns, L.

    1988-01-01

    Describes a simple high-performance liquid chromatography experiment for undergraduate biochemistry laboratories. The experiment illustrates the separation of polypeptides by a step gradient elution using a single pump instrument with no gradient attachments. Discusses instrumentation, analysis, a sample preparation, and results. (CW)

  13. Investigating Student Perceptions of the Chemistry Laboratory and Their Approaches to Learning in the Laboratory

    Science.gov (United States)

    Berger, Spencer Granett

    This dissertation explores student perceptions of the instructional chemistry laboratory and the approaches students take when learning in the laboratory environment. To measure student perceptions of the chemistry laboratory, a survey instrument was developed. 413 students responded to the survey during the Fall 2011 semester. Students' perception of the usefulness of the laboratory in helping them learn chemistry in high school was related to several factors regarding their experiences in high school chemistry. Students' perception of the usefulness of the laboratory in helping them learn chemistry in college was also measured. Reasons students provided for the usefulness of the laboratory were categorized. To characterize approaches to learning in the laboratory, students were interviewed midway through semester (N=18). The interviews were used to create a framework describing learning approaches that students use in the laboratory environment. Students were categorized into three levels: students who view the laboratory as a requirement, students who believe that the laboratory augments their understanding, and students who view the laboratory as an important part of science. These categories describe the types of strategies students used when conducting experiments. To further explore the relationship between students' perception of the laboratory and their approaches to learning, two case studies are described. These case studies involve interviews in the beginning and end of the semester. In the interviews, students reflect on what they have learned in the laboratory and describe their perceptions of the laboratory environment. In order to encourage students to adopt higher-level approaches to learning in the laboratory, a metacognitive intervention was created. The intervention involved supplementary questions that students would answer while completing laboratory experiments. The questions were designed to encourage students to think critically about the

  14. Laboratory experiments in the study of the chemistry of the outer planets

    Science.gov (United States)

    Scattergood, Thomas W.

    1987-01-01

    It is shown that much information about planetary chemistry and physics can be gained through laboratory work. The types of experiments relevant to planetary research concern fundamental properties, spectral/optical properties, 'Miller-Urey' syntheses, and detailed syntheses. Specific examples of studies of the chemistry in the atmosphere of Titan are described with attention given to gas phase chemistry in the troposphere and the composition of model Titan aerosols. A list of work that still needs to be done is provided.

  15. Environmental Sciences Laboratory dedication, February 26-27, 1979

    International Nuclear Information System (INIS)

    Auerbach, S.I.; Millemann, N.T.

    1980-09-01

    The dedication of the new Environmental Sciences Laboratory coincided with the 25th year of the establishment of the science of ecology at Oak Ridge National Laboratory. That quarter century witnessed the evolution of ecology from an obscure, backwater discipline of biology to a broadly used, everyday household word. The transition reflected broad and basic changes in our social and cultural view of the world. This was brought about as a result of the awareness developed in our society of the importance of the environment, coupled with efforts of ecologists and other environmental scientists who identified, clarified, and formulated the issues and challenges of environmental protection for both the lay public and the scientific community. In many respects, the activities in ecology at ORNL were a microcosm of the broader social scene; the particular problems of the environment associated with atomic energy needed to be defined in scientific terms and articulated in both the specific and general sense for a larger audience which was unfamiliar with the field and somewhat alien to its concepts and philosophy. The success of this effort is reflected in the existence of the new Environmental Sciences Laboratory. This dedication volume brings together the thoughts and reflections of many of these scientists whose efforts contributed in a unique and individualistic fashion not only to ORNL but also to the national identification of ecology and its importance to the achievement of our national goals. Their remarks and presentations are not only a pleasant and personally gratifying recapitulation of the past and of ORNL's contributions to ecology but also portend some of the challenges to ecology in the future

  16. Environmental Sciences Laboratory dedication, February 26-27, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Auerbach, S.I.; Millemann, N.T. (eds.)

    1980-09-01

    The dedication of the new Environmental Sciences Laboratory coincided with the 25th year of the establishment of the science of ecology at Oak Ridge National Laboratory. That quarter century witnessed the evolution of ecology from an obscure, backwater discipline of biology to a broadly used, everyday household word. The transition reflected broad and basic changes in our social and cultural view of the world. This was brought about as a result of the awareness developed in our society of the importance of the environment, coupled with efforts of ecologists and other environmental scientists who identified, clarified, and formulated the issues and challenges of environmental protection for both the lay public and the scientific community. In many respects, the activities in ecology at ORNL were a microcosm of the broader social scene; the particular problems of the environment associated with atomic energy needed to be defined in scientific terms and articulated in both the specific and general sense for a larger audience which was unfamiliar with the field and somewhat alien to its concepts and philosophy. The success of this effort is reflected in the existence of the new Environmental Sciences Laboratory. This dedication volume brings together the thoughts and reflections of many of these scientists whose efforts contributed in a unique and individualistic fashion not only to ORNL but also to the national identification of ecology and its importance to the achievement of our national goals. Their remarks and presentations are not only a pleasant and personally gratifying recapitulation of the past and of ORNL's contributions to ecology but also portend some of the challenges to ecology in the future.

  17. Laboratory space physics: Investigating the physics of space plasmas in the laboratory

    Science.gov (United States)

    Howes, Gregory G.

    2018-05-01

    Laboratory experiments provide a valuable complement to explore the fundamental physics of space plasmas without the limitations inherent to spacecraft measurements. Specifically, experiments overcome the restriction that spacecraft measurements are made at only one (or a few) points in space, enable greater control of the plasma conditions and applied perturbations, can be reproducible, and are orders of magnitude less expensive than launching spacecraft. Here, I highlight key open questions about the physics of space plasmas and identify the aspects of these problems that can potentially be tackled in laboratory experiments. Several past successes in laboratory space physics provide concrete examples of how complementary experiments can contribute to our understanding of physical processes at play in the solar corona, solar wind, planetary magnetospheres, and the outer boundary of the heliosphere. I present developments on the horizon of laboratory space physics, identifying velocity space as a key new frontier, highlighting new and enhanced experimental facilities, and showcasing anticipated developments to produce improved diagnostics and innovative analysis methods. A strategy for future laboratory space physics investigations will be outlined, with explicit connections to specific fundamental plasma phenomena of interest.

  18. Transplant experiments uncover Baltic Sea basin-specific responses in bacterioplankton community composition and metabolic activities

    OpenAIRE

    Lindh, Markus V.; Figueroa, Daniela; Sjöstedt, Johanna; Baltar, Federico; Lundin, Daniel; Andersson, Agneta; Legrand, Catherine; Pinhassi, Jarone

    2015-01-01

    Anthropogenically induced changes in precipitation are projected to generate increased river runoff to semi-enclosed seas, intensifying loads of terrestrial dissolved organic matter and decreasing salinity. To determine how bacterial community structure and functioning adjust to such changes, we designed microcosm transplant experiments with Baltic Proper (salinity 7.2) and Bothnian Sea (salinity 3.6) water. Baltic Proper bacteria generally reached higher abundance than Bothnian Sea bacteria ...

  19. Solder wetting behavior enhancement via laser-textured surface microcosmic topography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haiyan [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Peng, Jianke [Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Fu, Li, E-mail: fuli@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Wang, Xincheng [Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Xie, Yan [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2016-04-15

    Graphical abstract: - Highlights: • The wetting angle of lead free solder on Cu was reduced by surface microstructure. • The wetting form of Sn-Ag-Cu solder on Cu was “non-composite surface”. • The experimental results had a sound fit with the theoretical calculation. - Abstract: In order to reduce or even replace the use of Sn-Pb solder in electronics industry, the laser-textured surface microstructures were used to enhance the wetting behavior of lead free solder during soldering. According to wetting theory and Sn-Ag-Cu lead free solder performance, we calculated and designed four microcosmic structures with the similar shape and different sizes to control the wetting behavior of lead free solder. The micro-structured surfaces with different dimensions were processed on copper plates by fiber femtosecond laser, and the effect of microstructures on wetting behavior was verified experimentally. The results showed that the wetting angle of Sn-Ag-Cu solder on the copper plate with microstructures decreased effectively compared with that on the smooth copper plate. The wetting angles had a sound fit with the theoretical values calculated by wetting model. The novel method provided a feasible route for adjusting the wetting behavior of solders and optimizing solders system.

  20. Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, Paul [Boston College, Chestnut Hill, MA (United States)

    2015-10-20

    Aerosols containing black carbon (and some specific types of organic particulate matter) directly absorb incoming light, heating the atmosphere. In addition, all aerosol particles backscatter solar light, leading to a net-cooling effect. Indirect effects involve hydrophilic aerosols, which serve as cloud condensation nuclei (CCN) that affect cloud cover and cloud stability, impacting both atmospheric radiation balance and precipitation patterns. At night, all clouds produce local warming, but overall clouds exert a net-cooling effect on the Earth. The effect of aerosol radiative forcing on climate may be as large as that of the greenhouse gases, but predominantly opposite in sign and much more uncertain. The uncertainties in the representation of aerosol interactions in climate models makes it problematic to use model projections to guide energy policy. The objective of our program is to reduce the uncertainties in the aerosol radiative forcing in the two areas highlighted in the ASR Science and Program Plan. That is, (1) addressing the direct effect by correlating particle chemistry and morphology with particle optical properties (i.e. absorption, scattering, extinction), and (2) addressing the indirect effect by correlating particle hygroscopicity and CCN activity with particle size, chemistry, and morphology. In this connection we are systematically studying particle formation, oxidation, and the effects of particle coating. The work is specifically focused on carbonaceous particles where the uncertainties in the climate relevant properties are the highest. The ongoing work consists of laboratory experiments and related instrument inter-comparison studies both coordinated with field and modeling studies, with the aim of providing reliable data to represent aerosol processes in climate models. The work is performed in the aerosol laboratory at Boston College. At the center of our laboratory setup are two main sources for the production of aerosol particles: (a

  1. Variability in Small Hive Beetle (Coleoptera: Nitidulidae) Reproduction in Laboratory and Field Experiments.

    Science.gov (United States)

    Meikle, William G; Holst, Niels; Cook, Steven C; Patt, Joseph M

    2015-06-01

    Experiments were conducted to examine how several key factors affect population growth of the small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae). Laboratory experiments were conducted to examine effects of food quantity and temperature on reproduction of cohorts of young A. tumida adults (1:1 sex ratio) housed in experimental arenas. Daily numbers and total mass of larvae exiting arenas were highly variable within treatment. Either one or two cohorts of larvae were observed exiting the arenas. Food quantity, either 10 g or 20 g, did not significantly affect the number of larvae exiting arenas at 32°C, but did at 28°C; arenas provided 20 g food produced significantly more larvae than arenas provided 10 g. Temperature did not affect the total mass of larvae provided 10 g food, but did affect larval mass provided 20 g; beetles kept at 28°C produced more larval mass than at 32°C. Field experiments were conducted to examine A. tumida reproductive success in full strength bee colonies. Beetles were introduced into hives as egg-infested frames and as adults, and some bee colonies were artificially weakened through removal of sealed brood. Efforts were unsuccessful; no larvae were observed exiting from, or during the inspection of, any hives. Possible reasons for these results are discussed. The variability observed in A. tumida reproduction even in controlled laboratory conditions and the difficulty in causing beetle infestations in field experiments involving full colonies suggest that accurately forecasting the A. tumida severity in such colonies will be difficult. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  2. A Laboratory Experiment, Based on the Maillard Reaction, Conducted as a Project in Introductory Statistics

    Science.gov (United States)

    Kravchuk, Olena; Elliott, Antony; Bhandari, Bhesh

    2005-01-01

    A simple laboratory experiment, based on the Maillard reaction, served as a project in Introductory Statistics for undergraduates in Food Science and Technology. By using the principles of randomization and replication and reflecting on the sources of variation in the experimental data, students reinforced the statistical concepts and techniques…

  3. Nitrification is a primary driver of nitrous oxide production in laboratory microcosms from different land-use soils

    Directory of Open Access Journals (Sweden)

    Rui Liu

    2016-09-01

    Full Text Available Most studies on soil N2O emissions have focused either on the quantifying of agricultural N2O fluxes or on the effect of environmental factors on N2O emissions. However very limited information is available on how land-use will affect N2O production, and nitrifiers involved in N2O emissions in agricultural soil ecosystems. Therefore, this study aimed at evaluating the relative importance of nitrification and denitrification to N2O emissions from different land-use soils and identifying the potential underlying microbial mechanisms. A 15N-tracing experiment was conducted under controlled laboratory conditions on four agricultural soils collected from different land-use. We measured N2O fluxes, nitrate (NO3− and ammonium (NH4+ concentration and15N2O, 15NO3− and 15NH4+ enrichment during the incubation. Quantitative PCR was used to quantify ammonia-oxidizing archaea (AOA and ammonia-oxidizing bacteria (AOB. Our results showed that nitrification was the main contributor to N2O production in soils from sugarcane, dairy pasture and cereal cropping systems, while denitrification played a major role in N2O production in the vegetable soil under the experimental conditions. Nitrification contributed to 96.7% of the N2O emissions in sugarcane soil followed by 71.3% in the cereal cropping soil and 70.9% in the dairy pasture soil, while only around 20.0% of N2O was produced from nitrification in vegetable soil. The proportion of nitrified nitrogen as N2O (PN2O value varied across different soils, with the highest PN2O value (0.26‰ found in the cereal cropping soil, which was around 10 times higher than that in other three systems. AOA were the abundant ammonia oxidizers, and were significantly correlated to N2O emitted from nitrification in the sugarcane soil, while AOB were significantly correlated with N2O emitted from nitrification in the cereal cropping soil. Our findings suggested that soil type and land-use might have strongly affected the

  4. Nitrification Is a Primary Driver of Nitrous Oxide Production in Laboratory Microcosms from Different Land-Use Soils.

    Science.gov (United States)

    Liu, Rui; Hu, Hangwei; Suter, Helen; Hayden, Helen L; He, Jizheng; Mele, Pauline; Chen, Deli

    2016-01-01

    Most studies on soil N2O emissions have focused either on the quantifying of agricultural N2O fluxes or on the effect of environmental factors on N2O emissions. However, very limited information is available on how land-use will affect N2O production, and nitrifiers involved in N2O emissions in agricultural soil ecosystems. Therefore, this study aimed at evaluating the relative importance of nitrification and denitrification to N2O emissions from different land-use soils and identifying the potential underlying microbial mechanisms. A (15)N-tracing experiment was conducted under controlled laboratory conditions on four agricultural soils collected from different land-use. We measured N2O fluxes, nitrate ([Formula: see text]), and ammonium ([Formula: see text]) concentration and (15)N2O, (15)[Formula: see text], and (15)[Formula: see text] enrichment during the incubation. Quantitative PCR was used to quantify ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Our results showed that nitrification was the main contributor to N2O production in soils from sugarcane, dairy pasture and cereal cropping systems, while denitrification played a major role in N2O production in the vegetable soil under the experimental conditions. Nitrification contributed to 96.7% of the N2O emissions in sugarcane soil followed by 71.3% in the cereal cropping soil and 70.9% in the dairy pasture soil, while only around 20.0% of N2O was produced from nitrification in vegetable soil. The proportion of nitrified nitrogen as N2O (PN2O-value) varied across different soils, with the highest PN2O-value (0.26‰) found in the cereal cropping soil, which was around 10 times higher than that in other three systems. AOA were the abundant ammonia oxidizers, and were significantly correlated to N2O emitted from nitrification in the sugarcane soil, while AOB were significantly correlated with N2O emitted from nitrification in the cereal cropping soil. Our findings suggested that soil

  5. Comparison of test results in the evaluation of the WSF of several jet fuels using the standardized aquatic microcosm and the mixed flask culture protocols

    International Nuclear Information System (INIS)

    Landis, W.G.; Matthews, R.A.; Markiewicz, A.J.; Matthews, G.B.

    1993-01-01

    The water soluble fraction of the turbine fuels Jet-A, JP-4 and JP-8 have been examines as stressors for two microcosm protocols, the standardized aquatic microcosm (SAM) and the mixed flask culture (MFC). The SAM is a 3 L system inoculated with standard cultures of algae, zooplankton, bacteria, protozoa. In contrast, the MFC is 1 L and is inoculated with a complex mixture of organisms derived from a natural source. Analysis of the organism counts and physical data were conducted using conventional and newly derived multivariate methods. Physical parameters, such as pH and oxygen metabolism, were often not as sensitive as species and bacterial counts. Like the SAM system, species numbers and other variables that determined clusters varied among sampling dates. Compared to the larger yet simpler system, the MFC exhibits more violent dynamics and is more likely to become catastrophically fixated, as in systems dominated by cyanobacteria. The combination of greater diversity and smaller volume may contribute to the volatile or chaotic dynamics of the MFC system

  6. On the possibility of measuring the Earth's gravitomagnetic force in a new laboratory experiment

    International Nuclear Information System (INIS)

    Iorio, Lorenzo

    2003-01-01

    In this letter we propose, in a preliminary way, a new Earth-based laboratory experiment aimed at the detection of the gravitomagnetic field of the Earth. It consists of the measurement of the difference between the circular frequencies of two rotators moving along identical circular paths, but in opposite directions, on a horizontal friction-free plane in a vacuum chamber placed at the South Pole. The accuracy to our knowledge of the Earth's rotation from VLBI and the possibility of measuring the rotators' periods over many revolutions should allow for the feasibility of the proposed experiment. (letter to the editor)

  7. Diverse Reductive Dehalogenases Are Associated with Clostridiales-Enriched Microcosms Dechlorinating 1,2-Dichloroethane

    KAUST Repository

    Merlino, Giuseppe; Balloi, Annalisa; Marzorati, Massimo; Mapelli, Francesca; Rizzi, Aurora; Lavazza, Davide; de Ferra, Francesca; Carpani, Giovanna; Daffonchio, Daniele

    2015-01-01

    The achievement of successful biostimulation of active microbiomes for the cleanup of a polluted site is strictly dependent on the knowledge of the key microorganisms equipped with the relevant catabolic genes responsible for the degradation process. In this work, we present the characterization of the bacterial community developed in anaerobic microcosms after biostimulation with the electron donor lactate of groundwater polluted with 1,2-dichloroethane (1,2-DCA). Through a multilevel analysis, we have assessed (i) the structural analysis of the bacterial community; (ii) the identification of putative dehalorespiring bacteria; (iii) the characterization of functional genes encoding for putative 1,2-DCA reductive dehalogenases (RDs). Following the biostimulation treatment, the structure of the bacterial community underwent a notable change of the main phylotypes, with the enrichment of representatives of the order Clostridiales . Through PCR targeting conserved regions within known RD genes, four novel variants of RDs previously associated with the reductive dechlorination of 1,2-DCA were identified in the metagenome of the Clostridiales-dominated bacterial community.

  8. Diverse Reductive Dehalogenases Are Associated with Clostridiales-Enriched Microcosms Dechlorinating 1,2-Dichloroethane

    KAUST Repository

    Merlino, Giuseppe

    2015-03-06

    The achievement of successful biostimulation of active microbiomes for the cleanup of a polluted site is strictly dependent on the knowledge of the key microorganisms equipped with the relevant catabolic genes responsible for the degradation process. In this work, we present the characterization of the bacterial community developed in anaerobic microcosms after biostimulation with the electron donor lactate of groundwater polluted with 1,2-dichloroethane (1,2-DCA). Through a multilevel analysis, we have assessed (i) the structural analysis of the bacterial community; (ii) the identification of putative dehalorespiring bacteria; (iii) the characterization of functional genes encoding for putative 1,2-DCA reductive dehalogenases (RDs). Following the biostimulation treatment, the structure of the bacterial community underwent a notable change of the main phylotypes, with the enrichment of representatives of the order Clostridiales . Through PCR targeting conserved regions within known RD genes, four novel variants of RDs previously associated with the reductive dechlorination of 1,2-DCA were identified in the metagenome of the Clostridiales-dominated bacterial community.

  9. Rhizosphere effect of colonizer plant species on the development of soil microbial community during primary succession on postmining sites

    Energy Technology Data Exchange (ETDEWEB)

    Elhottova, D.; Kristufek, V.; Maly, S.; Frouz, J. [Academy of Sciences of the Czech Republic, Ceske Budejovice (Czech Republic). Inst. for Soil Biology

    2009-07-01

    The impact of pioneer plant species Tussilago farfara on structural, functional, and growth characterization of microbial community colonizing the spoil colliery substrate was studied in a laboratory microcosm experiment. Microcosms consisting of spoil substrate (0.7 dm{sup 3} of tertiary alkaline clay sediment from Sokolov brown-coal mine area) from a pioneer site (without vegetation, 5 years after heaping) were cultivated in a greenhouse with one plant of this species. Plant roots substantially increased microbial diversity and biomass after one season (7 months) of cultivation. Roots influenced the microbial community and had nearly twice the size, higher growth, and metabolic potential in comparison to the control. The development of microbial specialists improves the plant nutrient status. Bacterial nitrogen (N{sub 2}) fixators (Bradyrhizobium japonicum, Rhizobium radiobacter) and arbuscular mycorrhizal fungi were confirmed in the rhizosphere of Tussilago farfara.

  10. Gravimetric Analysis of Bismuth in Bismuth Subsalicylate Tablets: A Versatile Quantitative Experiment for Undergraduate Laboratories

    Science.gov (United States)

    Davis, Eric; Cheung, Ken; Pauls, Steve; Dick, Jonathan; Roth, Elijah; Zalewski, Nicole; Veldhuizen, Christopher; Coeler, Joel

    2015-01-01

    In this laboratory experiment, lower- and upper-division students dissolved bismuth subsalicylate tablets in acid and precipitated the resultant Bi[superscript 3+] in solution with sodium phosphate for a gravimetric determination of bismuth subsalicylate in the tablets. With a labeled concentration of 262 mg/tablet, the combined data from three…

  11. Positive experiences of volunteers working in deployable laboratories in West Africa during the Ebola outbreak.

    NARCIS (Netherlands)

    Belfroid, Evelien; Mollers, Madelief; Smit, Pieter W; Hulscher, Marlies; Koopmans, Marion; Reusken, Chantal; Timen, Aura

    2018-01-01

    The largest outbreak of Ebola virus disease ever started in West Africa in December 2013; it created a pressing need to expand the workforce dealing with it. The aim of this study was to gain insight into the experiences of volunteers from the European Union who worked in deployable laboratories in

  12. Reform in a General Chemistry Laboratory: How Do Students Experience Change in the Instructional Approach?

    Science.gov (United States)

    Chopra, I.; O'Connor, J.; Pancho, R.; Chrzanowski, M.; Sandi-Urena, S.

    2017-01-01

    This qualitative study investigated the experience of a cohort of students exposed consecutively to two substantially different environments in their General Chemistry Laboratory programme. To this end, the first semester in a traditional expository programme was followed by a semester in a cooperative, problem-based, multi-week format. The focus…

  13. LabView Based Nuclear Physics Laboratory experiments as a remote teaching and training tool for Latin American Educational Centers

    International Nuclear Information System (INIS)

    Sajo-Bohus, L.; Greaves, E. D.; Barros, H.; Gonzalez, W.; Rangel, A.

    2007-01-01

    A virtual laboratory via internet to provide a highly iterative and powerful teaching tool for scientific and technical discipline is given. The experimenter takes advantage of a virtual laboratory and he can execute nuclear experiment at introductory level e.g. Gamma ray detection with Geiger-Mueller Counter at remote location using internet communication technology

  14. Manure biochar influence upon soil properties, phosphorus distribution and phosphatase activities: A microcosm incubation study.

    Science.gov (United States)

    Jin, Yi; Liang, Xinqiang; He, Miaomiao; Liu, Yu; Tian, Guangming; Shi, Jiyan

    2016-01-01

    Using manure-derived-biochar as an alternative phosphorus (P) source has bright future prospects to improve soil P status. A 98-day microcosm incubation experiment was set up for two soils which were amended with manure biochar at proportions of 0, 0.5% and 1.5%. Swine manure samples were air-dried and manure biochar was prepared by pyrolysis at 400 °C for 4 h. As determined by P-31 nuclear magnetic resonance ((31)P NMR) spectroscopy, manure biochar mainly increased the contents and fractions of orthophosphate and pyrophosphate in two soils, while decreased those of monoesters (P<0.05). At the end of incubation, 1.5% of manure biochar raised soil pH by 0.5 and 0.6 units, cation exchange capacity by 16.9% and 32.2%, and soil total P by 82.1% and 81.1% for silt loam and clay loam soils, respectively, as compared with those soils without biochar. Simultaneously, 1.5% of manure biochar decreased acid phosphomonoesterase activities by 18.6% and 34.0% for clay loam and silt loam, respectively; while it increased alkaline phosphomonoesterase activities by 28.5% and 95.1% for clay loam and silt loam, respectively. The enhancement of soil P availability after manure biochar addition was firstly due to the orthophosphate and pyrophosphate as the major P species in manure biochar which directly increased contents of soil inorganic P, and also attributed to the decomposition of some organic P like monoesters by enhanced alkaline phosphomonoesterase activities from manure biochar addition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Mineralization of PAHs in coal-tar impacted aquifer sediments and associated microbial community structure investigated with FISH

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, S W; Ong, S K; Moorman, T B [Iowa State University, Ames, IA (USA)

    2007-11-15

    The microbial community structure and mineralization of polycyclic aromatic hydrocarbons (PAHs) in a coal-tar contaminated aquifer were investigated spatially using fluorescence in situ hybridization (FISH) and in laboratory-scale incubations of the aquifer sediments. DAPI-detected microbial populations in the contaminated sediments were three orders of magnitude greater than nearby uncontaminated sediments, suggesting growth on coal-tar constituents in situ. Actinobacteria, {beta}- and {gamma}-Proteobacteria, and Flavobacteria dominated the in situ aerobic (> 1 mg l{sup -1} dissolved oxygen) microbial community, whereas sulfate-reducing bacteria comprised 37% of the microbial community in the sulfidogenic region of the aquifer. Rapid mineralization of naphthalene and phenanthrene were observed in aerobic laboratory microcosms and resulted in significant enrichment of {beta}- and {gamma}-Proteobacteria potentially explaining their elevated presence in situ. Nitrate- and sulfate-limited mineralization of naphthalene in laboratory microcosms occurred to a small degree in aquifer sediments from locations where groundwater chemistry indicated nitrate- and sulfate-reduction, respectively. The results of this study suggest that FISH may be a useful tool for providing a link between laboratory microcosms and groundwater measurements made in situ necessary to better demonstrate the potential for natural attenuation at complex PAH contaminated sites.

  16. Coulometric Titration of Ethylenediaminetetraacetate (EDTA) with Spectrophotometric Endpoint Detection: An Experiment for the Instrumental Analysis Laboratory

    Science.gov (United States)

    Williams, Kathryn R.; Young, Vaneica Y.; Killian, Benjamin J.

    2011-01-01

    Ethylenediaminetetraacetate (EDTA) is commonly used as an anticoagulant in blood-collection procedures. In this experiment for the instrumental analysis laboratory, students determine the quantity of EDTA in commercial collection tubes by coulometric titration with electrolytically generated Cu[superscript 2+]. The endpoint is detected…

  17. Variability of Biological Degradation of Aromatic Hydrocarbons in an Aerobic Aquifer Determined by Laboratory Batch Experiments

    DEFF Research Database (Denmark)

    Nielsen, Per Henning; Christensen, Thomas Højlund

    1994-01-01

    The biological aerobic degradation of 7 aromatic hydrocarbons (benzene, toluene, o-xylene, p-dichlorobenzene, o-dichlorobenzene, naphthalene and biphenyl) was studied for 149 days in replicate laboratory batch experiments with groundwater and sediment from 8 localities representing a 15 m × 30 m...

  18. Genetically engineered Pseudomonas putida X3 strain and its potential ability to bioremediate soil microcosms contaminated with methyl parathion and cadmium.

    Science.gov (United States)

    Zhang, Rong; Xu, Xingjian; Chen, Wenli; Huang, Qiaoyun

    2016-02-01

    A multifunctional Pseudomonas putida X3 strain was successfully engineered by introducing methyl parathion (MP)-degrading gene and enhanced green fluorescent protein (EGFP) gene in P. putida X4 (CCTCC: 209319). In liquid cultures, the engineered X3 strain utilized MP as sole carbon source for growth and degraded 100 mg L(-1) of MP within 24 h; however, this strain did not further metabolize p-nitrophenol (PNP), an intermediate metabolite of MP. No discrepancy in minimum inhibitory concentrations (MICs) to cadmium (Cd), copper (Cu), zinc (Zn), and cobalt (Co) was observed between the engineered X3 strain and its host strain. The inoculated X3 strain accelerated MP degradation in different polluted soil microcosms with 100 mg MP kg(-1) dry soil and/or 5 mg Cd kg(-1) dry soil; MP was completely eliminated within 40 h. However, the presence of Cd in the early stage of remediation slightly delayed MP degradation. The application of X3 strain in Cd-contaminated soil strongly affected the distribution of Cd fractions and immobilized Cd by reducing bioavailable Cd concentrations with lower soluble/exchangeable Cd and organic-bound Cd. The inoculated X3 strain also colonized and proliferated in various contaminated microcosms. Our results suggested that the engineered X3 strain is a potential bioremediation agent showing competitive advantage in complex contaminated environments.

  19. Gene expression analysis of 4 biomarker candidates in Eisenia fetida exposed to an environmental metallic trace elements gradient: A microcosm study

    Energy Technology Data Exchange (ETDEWEB)

    Brulle, Franck; Lemiere, Sebastien [Univ Lille Nord de France, F-59000 Lille (France); LGCgE, Equipe Ecologie Numerique et Ecotoxicologie, Lille 1, F-59650 Villeneuve d' Ascq (France); Waterlot, Christophe; Douay, Francis [Univ Lille Nord de France, F-59000 Lille (France); LGCgE, Equipe Sols et Environnement, Groupe ISA, 48 boulevard Vauban, F-59046 Lille Cedex (France); Vandenbulcke, Franck, E-mail: franck.vandenbulcke@univ-lille1.fr [Univ Lille Nord de France, F-59000 Lille (France); LGCgE, Equipe Ecologie Numerique et Ecotoxicologie, Lille 1, F-59650 Villeneuve d' Ascq (France)

    2011-11-15

    Past activities of 2 smelters (Metaleurop Nord and Nyrstar) led to the accumulation of high amounts of Metal Trace Elements (TEs) in top soils of the Noyelles-Godault/Auby area, Northern France. Earthworms were exposed to polluted soils collected in this area to study and better understand the physiological changes, the mechanisms of acclimation, and detoxification resulting from TE exposure. Previously we have cloned and transcriptionally characterized potential biomarkers from immune cells of the ecotoxicologically important earthworm species Eisenia fetida exposed in vivo to TE-spiked standard soils. In the present study, analysis of expression kinetics of four candidate indicator genes (Cadmium-metallothionein, coactosin like protein, phytochelatin synthase and lysenin) was performed in E. fetida after microcosm exposures to natural soils exhibiting an environmental cadmium (Cd) gradient in a kinetic manner. TE body burdens were also measured. This microcosm study provided insights into: (1) the ability of the 4 tested genes to serve as expression biomarkers, (2) detoxification processes through the expression analysis of selected genes, and (3) influence of land uses on the response of potential biomarkers (gene expression or TE uptake). - Highlights: {yields} Expression biomarkers in animals exposed to Cadmium-contaminated field soils. {yields} Expression kinetics to test the ability of genes to serve as expression biomarkers. {yields} Study of detoxification processes through the expression analysis of selected genes.

  20. Undergraduate Organic Chemistry Laboratory Safety

    Science.gov (United States)

    Luckenbaugh, Raymond W.

    1996-11-01

    Each organic chemistry student should become familiar with the educational and governmental laboratory safety requirements. One method for teaching laboratory safety is to assign each student to locate safety resources for a specific class laboratory experiment. The student should obtain toxicity and hazardous information for all chemicals used or produced during the assigned experiment. For example, what is the LD50 or LC50 for each chemical? Are there any specific hazards for these chemicals, carcinogen, mutagen, teratogen, neurotixin, chronic toxin, corrosive, flammable, or explosive agent? The school's "Chemical Hygiene Plan", "Prudent Practices for Handling Hazardous Chemicals in the Laboratory" (National Academy Press), and "Laboratory Standards, Part 1910 - Occupational Safety and Health Standards" (Fed. Register 1/31/90, 55, 3227-3335) should be reviewed for laboratory safety requirements for the assigned experiment. For example, what are the procedures for safe handling of vacuum systems, if a vacuum distillation is used in the assigned experiment? The literature survey must be submitted to the laboratory instructor one week prior to the laboratory session for review and approval. The student should then give a short presentation to the class on the chemicals' toxicity and hazards and describe the safety precautions that must be followed. This procedure gives the student first-hand knowledge on how to find and evaluate information to meet laboartory safety requirements.

  1. Scaled laboratory experiments explain the kink behaviour of the Crab Nebula jet.

    Science.gov (United States)

    Li, C K; Tzeferacos, P; Lamb, D; Gregori, G; Norreys, P A; Rosenberg, M J; Follett, R K; Froula, D H; Koenig, M; Seguin, F H; Frenje, J A; Rinderknecht, H G; Sio, H; Zylstra, A B; Petrasso, R D; Amendt, P A; Park, H S; Remington, B A; Ryutov, D D; Wilks, S C; Betti, R; Frank, A; Hu, S X; Sangster, T C; Hartigan, P; Drake, R P; Kuranz, C C; Lebedev, S V; Woolsey, N C

    2016-10-07

    The remarkable discovery by the Chandra X-ray observatory that the Crab nebula's jet periodically changes direction provides a challenge to our understanding of astrophysical jet dynamics. It has been suggested that this phenomenon may be the consequence of magnetic fields and magnetohydrodynamic instabilities, but experimental demonstration in a controlled laboratory environment has remained elusive. Here we report experiments that use high-power lasers to create a plasma jet that can be directly compared with the Crab jet through well-defined physical scaling laws. The jet generates its own embedded toroidal magnetic fields; as it moves, plasma instabilities result in multiple deflections of the propagation direction, mimicking the kink behaviour of the Crab jet. The experiment is modelled with three-dimensional numerical simulations that show exactly how the instability develops and results in changes of direction of the jet.

  2. Laboratory Experiments to Stimulate CO2 Ocean Disposal

    International Nuclear Information System (INIS)

    Masutani, S.M.

    1997-01-01

    This Technical Progress Report summarizes activities conducted over the period 8/16/96-2/15/97 as part of this project. This investigation responds to the possibility that restrictions on greenhouse gas emissions may be imposed in the future to comply with the Framework Convention on Climate Change. The primary objective of the investigation is to obtain experimental data that can be applied to assess the technical feasibility and environmental impacts of oceanic containment strategies to limit release of carbon dioxide (CO 2 ) from coal and other fossil fuel combustion systems into the atmosphere. Critical technical uncertainties of ocean disposal of CO 2 will be addressed by performing experiments that: (1) characterize size spectra and velocities of a dispersed CO 2 phase in the near-field of a discharge jet; and (2) estimate rates of mass transfer from dissolving droplets of liquid CO 2 encased in a thin hydrate shell. Experiments will be conducted in a laboratory facility that can reproduce conditions in the ocean to depths of 600 m (1,969 ft). Between 8/16/96 and 2/15/97, activities focused on modifications to the experimental apparatus and the testing of diagnostics. Following completion of these tasks, experiments will be initiated and will continue through the end of the 36 month period of performance. Major accomplishments of this reporting period were: (1) delivery, set-up, and testing of the PDPA (Phase Doppler Particle Analyzer), which will be the principal diagnostic of the continuous CO 2 jet injection tests; (2) presentation of research papers and posters at the 212th American Chemical Society National Meeting and the Third International Conference on Carbon Dioxide Removal; (3) participation in the 4th Expert Workshop on Ocean Storage of Carbon Dioxide; (4) execution of an Agreement with ABB Management, Ltd. to support and extend the activities of this grant; and (5) initiation of research collaborations with Dr. P.M. Haugen of the University of

  3. 29th November 2011 - Czech Parliament Members of the Social Committee of the Lower Chamber visiting CERN permanent exhibition Microcosm and ATLAS visitor centre with Senior Czech Physicist and ILO I. Lehraus.

    CERN Multimedia

    Jean-Claude Gadmer

    2011-01-01

    29th November 2011 - Czech Parliament Members of the Social Committee of the Lower Chamber visiting CERN permanent exhibition Microcosm and ATLAS visitor centre with Senior Czech Physicist and ILO I. Lehraus.

  4. A laboratory plasma experiment for studying magnetic dynamics of accretion discs and jets

    OpenAIRE

    Hsu, S. C.; Bellan, P. M.

    2002-01-01

    This work describes a laboratory plasma experiment and initial results which should give insight into the magnetic dynamics of accretion discs and jets. A high-speed multiple-frame CCD camera reveals images of the formation and helical instability of a collimated plasma, similar to MHD models of disc jets, and also plasma detachment associated with spheromak formation, which may have relevance to disc winds and flares. The plasmas are produced by a planar magnetized coaxial gun. The resulting...

  5. The effect of noise in a performance measure on work motivation: A real effort laboratory experiment

    NARCIS (Netherlands)

    Sloof, R.; van Praag, C.M.

    2008-01-01

    This paper reports the results of an individual real effort laboratory experiment where subjects are paid for measured performance. Measured performance equals actual performance plus noise. We compare a stable environment where the noise is small with a volatile environment where the noise is

  6. Hands-On Experiences of Undergraduate Students in Automatics and Robotics Using a Virtual and Remote Laboratory

    Science.gov (United States)

    Jara, Carlos A.; Candelas, Francisco A.; Puente, Santiago T.; Torres, Fernando

    2011-01-01

    Automatics and Robotics subjects are always greatly improved when classroom teaching is supported by adequate laboratory courses and experiments following the "learning by doing" paradigm, which provides students a deep understanding of theoretical lessons. However, expensive equipment and limited time prevent teachers having sufficient…

  7. The effect of noise in a performance measure on work motivation: A real effort laboratory experiment

    NARCIS (Netherlands)

    Sloof, R.; van Praag, C.M.

    2010-01-01

    This paper reports the results of an individual real effort laboratory experiment where subjects are paid for measured performance. Measured performance equals actual performance plus noise. We compare a stable environment where the noise is small with a volatile environment where the noise is

  8. Recent Progress on the magnetic turbulence experiment at the Bryn Mawr Plasma Laboratory

    Science.gov (United States)

    Schaffner, D. A.; Cartagena-Sanchez, C. A.; Johnson, H. K.; Fahim, L. E.; Fiedler-Kawaguchi, C.; Douglas-Mann, E.

    2017-10-01

    Recent progress is reported on the construction, implementation and testing of the magnetic turbulence experiment at the Bryn Mawr Plasma Laboratory (BMPL). The experiment at the BMPL consists of an ( 300 μs) long coaxial plasma gun discharge that injects magnetic helicity into a flux-conserving chamber in a process akin to sustained slow-formation of spheromaks. A 24cm by 2m cylindrical chamber has been constructed with a high density axial port array to enable detailed simultaneous spatial measurements of magnetic and plasma fluctuations. Careful positioning of the magnetic structure produced by the three separately pulsed coils (one internal, two external) are preformed to optimize for continuous injection of turbulent magnetized plasma. High frequency calibration of magnetic probes is also underway using a power amplifier.

  9. Digital Data Acquisition System for experiments with segmented detectors at National Superconducting Cyclotron Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Starosta, K., E-mail: starosta@sfu.c [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Crawford, H.; Mantica, P. [National Superconducting Cyclotron Laboratory and Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W.K. [XIA LLC, Hayward, CA 94544 (United States)

    2009-11-11

    A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a gamma ray in a SeGA detector from implementation of gamma-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.

  10. Digital Data Acquisition System for experiments with segmented detectors at National Superconducting Cyclotron Laboratory

    International Nuclear Information System (INIS)

    Starosta, K.; Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T.; Crawford, H.; Mantica, P.; Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W.K.

    2009-01-01

    A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a γ ray in a SeGA detector from implementation of γ-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.

  11. Digital Data Acquisition System for experiments with segmented detectors at National Superconducting Cyclotron Laboratory

    Science.gov (United States)

    Starosta, K.; Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T.; Crawford, H.; Mantica, P.; Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W. K.

    2009-11-01

    A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a γ ray in a SeGA detector from implementation of γ-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.

  12. DHCVIM - a direct heating containment vessel interactions module: applications to Sandia National Laboratories Surtsey experiments

    International Nuclear Information System (INIS)

    Ginsberg, T.; Tutu, N.K.

    1987-01-01

    Direct containment heating is the mechanism of severe nuclear reactor accident containment loading that results from transfer of thermal and chemical energy from high-temperature, finely divided, molten core material to the containment atmosphere. The direct heating containment vessel interactions module (DHCVIM) has been developed at Brookhaven National Laboratory to model the mechanisms of containment loading resulting from the direct heating accident sequence. The calculational procedure is being used at present to model the Sandia National Laboratories one-tenth-scale Surtsey direct containment heating experiments. The objective of the code is to provide a test bed for detailed modeling of various aspects of the thermal, chemical, and hydrodynamic interactions that are expected to occur in three regions of a containment building: reactor cavity, intermediate subcompartments, and containment dome. Major emphasis is placed on the description of reactor cavity dynamics. This paper summarizes the modeling principles that are incorporated in DHCVIM and presents a prediction of the Surtsey Test DCH-2 that was made prior to execution of the experiment

  13. Interrelationship between Plasma Experiments in the Laboratory and in Space

    Energy Technology Data Exchange (ETDEWEB)

    Koepke, Mark E. [West Virginia Univ., Morgantown, WV (United States)

    2017-05-25

    Funds were expended to offset the travel costs of three students and three postdoctoral research associates to participate in and present work at the 2015 International Workshop on the Interrelationship between Plasma Experiments in the Laboratory and in Space (IPELS2015), 23-28 August 2015, Pitlochry, Scotland, UK. Selection was priority-ranked by lab-space engagement, first, and topic relevance, second. Supplementary selection preference was applied to under-represented populations, applicants lacking available travel-resources in their home research group, applicants unusually distant from the conference venue, and the impact of the applicant’s attendance in increasing the diversity of conference participation. One support letter per student was required. The letters described the specific benefit of IPELS2015 to the student dissertation or the postdoc career development, and document the evidence for the ordering criteria.

  14. Feasibility of establishing a biosafety level 3 tuberculosis culture laboratory of acceptable quality standards in a resource-limited setting: an experience from Uganda.

    Science.gov (United States)

    Ssengooba, Willy; Gelderbloem, Sebastian J; Mboowa, Gerald; Wajja, Anne; Namaganda, Carolyn; Musoke, Philippa; Mayanja-Kizza, Harriet; Joloba, Moses Lutaakome

    2015-01-15

    Despite the recent innovations in tuberculosis (TB) and multi-drug resistant TB (MDR-TB) diagnosis, culture remains vital for difficult-to-diagnose patients, baseline and end-point determination for novel vaccines and drug trials. Herein, we share our experience of establishing a BSL-3 culture facility in Uganda as well as 3-years performance indicators and post-TB vaccine trials (pioneer) and funding experience of sustaining such a facility. Between September 2008 and April 2009, the laboratory was set-up with financial support from external partners. After an initial procedure validation phase in parallel with the National TB Reference Laboratory (NTRL) and legal approvals, the laboratory registered for external quality assessment (EQA) from the NTRL, WHO, National Health Laboratories Services (NHLS), and the College of American Pathologists (CAP). The laboratory also instituted a functional quality management system (QMS). Pioneer funding ended in 2012 and the laboratory remained in self-sustainability mode. The laboratory achieved internationally acceptable standards in both structural and biosafety requirements. Of the 14 patient samples analyzed in the procedural validation phase, agreement for all tests with NTRL was 90% (P 80% in all years from NTRL, CAP, and NHLS, and culture was 100% for CAP panels and above regional average scores for all years with NHLS. Quarterly DST scores from WHO-EQA ranged from 78% to 100% in 2010, 80% to 100% in 2011, and 90 to 100% in 2012. From our experience, it is feasible to set-up a BSL-3 TB culture laboratory with acceptable quality performance standards in resource-limited countries. With the demonstrated quality of work, the laboratory attracted more research groups and post-pioneer funding, which helped to ensure sustainability. The high skilled experts in this research laboratory also continue to provide an excellent resource for the needed national discussion of the laboratory and quality management systems.

  15. Role of Organic Acids in Bioformation of Kaolinite: Results of Laboratory Experiments

    Science.gov (United States)

    Bontognali, T. R. R.; Vasconcelos, C.; McKenzie, J. A.

    2012-04-01

    Clay minerals and other solid silica phases have a broad distribution in the geological record and greatly affect fundamental physicochemical properties of sedimentary rocks, including porosity. An increasing number of studies suggests that microbial activity and microbially produced organic acids might play an important role in authigenic clay mineral formation, at low temperatures and under neutral pH conditions. In particular, early laboratory experiments (Linares and Huertas, 1971) reported the precipitation of kaolinite in solutions of SiO2 and Al2O3 with different molar ratios SiO2/Al2O3, together with fulvic acid (a non-characterized mixture of many different acids containing carboxyl and phenolate groups) that was extracted from peat soil. Despite many attempts, these experiments could not be reproduced until recently. Fiore et al. (2011) hypothesized that the non-sterile fulvic acid might have contained microbes that participated in the formation of kaolinite. Using solutions saturated with Si and Al and containing oxalate and/or mixed microbial culture extracted from peat-moss soil, they performed incubation experiments, which produced kaolinite exclusively in solutions containing oxalate and microbes. We proposed to test the role of specific organic acids for kaolinite formation, conducting laboratory experiments at 25˚C, with solutions of sodium silicate, aluminum chloride and various organic compounds (i.e. EDTA, citric acid, succinic acid and oxalic acid). Specific organic acids may stabilize aluminum in octahedral coordination positions, which is crucial for the initial nucleation step. In our experiments, a poorly crystalline mineral that is possibly a kaolinite precursor formed exclusively in the presence of succinic acid. In experiments with other organic compounds, no incorporation of Al was observed, and amorphous silica was the only precipitated phase. In natural environments, succinic acid is produced by a large variety of microbes as an

  16. Meteorological Development Laboratory Student Career Experience Program

    Science.gov (United States)

    McCalla, C., Sr.

    2007-12-01

    The National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) provides weather, hydrologic, and climate forecasts and warnings for the protection of life and property and the enhancement of the national economy. The NWS's Meteorological Development Laboratory (MDL) supports this mission by developing meteorological prediction methods. Given this mission, NOAA, NWS, and MDL all have a need to continually recruit talented scientists. One avenue for recruiting such talented scientist is the Student Career Experience Program (SCEP). Through SCEP, MDL offers undergraduate and graduate students majoring in meteorology, computer science, mathematics, oceanography, physics, and statistics the opportunity to alternate full-time paid employment with periods of full-time study. Using SCEP as a recruiting vehicle, MDL has employed students who possess some of the very latest technical skills and knowledge needed to make meaningful contributions to projects within the lab. MDL has recently expanded its use of SCEP and has increased the number of students (sometimes called co- ops) in its program. As a co-op, a student can expect to develop and implement computer based scientific techniques, participate in the development of statistical algorithms, assist in the analysis of meteorological data, and verify forecasts. This presentation will focus on describing recruitment, projects, and the application process related to MDL's SCEP. In addition, this presentation will also briefly explore the career paths of students who successfully completed the program.

  17. Safety research experiment facilities, Idaho National Engineering Laboratory, Idaho. Final environmental impact statement

    International Nuclear Information System (INIS)

    Liverman, J.L.

    1977-09-01

    This environmental statement was prepared for the Safety Research Experiment Facilities (SAREF) Project. The purpose of the proposed project is to modify some existing facilities and provide a new test facility at the Idaho National Engineering Laboratory (INEL) for conducting fast breeder reactor (FBR) safety experiments. The SAREF Project proposal has been developed after an extensive study which identified the FBR safety research needs requiring in-reactor experiments and which evaluated the capability of various existing and new facilities to meet these needs. The proposed facilities provide for the in-reactor testing of large bundles of prototypical FBR fuel elements under a wide variety of conditions, ranging from those abnormal operating conditions which might be expected to occur during the life of an FBR power plant to the extremely low probability, hypothetical accidents used in the evaluation of some design options and in the assessment of the long-term potential risk associated with wide-acale deployment of the FBR

  18. A simple laboratory experiment to measure the surface tension of a liquid in contact with air

    International Nuclear Information System (INIS)

    Riba, Jordi-Roger; Esteban, Bernat

    2014-01-01

    A simple and accurate laboratory experiment to measure the surface tension of liquids has been developed, which is well suited to teach the behaviour of liquids to first- or second-year students of physics, engineering or chemistry. The experimental setup requires relatively inexpensive equipment usually found in physics and chemistry laboratories, since it consists of a used or recycled burette, an analytical balance and a stereoscopic microscope or a micrometer. Experimental data and error analysis show that the surface tension of distilled water, 1-butanol and glycerol can be determined with accuracy better than 1.4%. (paper)

  19. Red Seaweed Enzyme-Catalyzed Bromination of Bromophenol Red: An Inquiry-Based Kinetics Laboratory Experiment for Undergraduates

    Science.gov (United States)

    Jittam, Piyachat; Boonsiri, Patcharee; Promptmas, Chamras; Sriwattanarothai, Namkang; Archavarungson, Nattinee; Ruenwongsa, Pintip; Panijpan, Bhinyo

    2009-01-01

    Haloperoxidase enzymes are of interest for basic and applied bioscientists because of their increasing importance in pharmaceutical industry and environmental cleanups. In a guided inquiry-based laboratory experiment for life-science, agricultural science, and health science undergraduates, the bromoperoxidase from a red seaweed was used to…

  20. Undergraduate Student Attitudes and Perceptions toward Low- and High-Level Inquiry Exercise Physiology Teaching Laboratory Experiences

    Science.gov (United States)

    Henige, Kim

    2011-01-01

    The purpose of this investigation was to compare student attitudes toward two different science laboratory learning experiences, specifically, traditional, cookbook-style, low-inquiry level (LL) activities and a high-inquiry level (HL) investigative project. In addition, we sought to measure and compare students' science-related attitudes and…

  1. Current sheets in the Earth’s magnetosphere and in laboratory experiments: The magnetic field structure and the Hall effect

    International Nuclear Information System (INIS)

    Frank, A. G.; Artemyev, A. V.; Zelenyi, L. M.

    2016-01-01

    The main characteristics of current sheets (CSs) formed in laboratory experiments are compared with the results of satellite observations of CSs in the Earth’s magnetotail. We show that many significant features of the magnetic field structure and the distributions of plasma parameters in laboratory and magnetospheric CSs exhibit a qualitative similarity, despite the enormous differences of scales, absolute values of plasma parameters, magnetic fields, and currents. In addition to a qualitative comparison, we give a number of dimensionless parameters that demonstrate the possibility of laboratory modeling of the processes occurring in the magnetosphere.

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

    Science.gov (United States)

    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

  3. ENTRY 2003: The international workshop on reliable performance assessment through laboratory experiments and ground surface investigations. 10th anniversary of ENTRY

    International Nuclear Information System (INIS)

    Ishikawa, Hirohisa; Yui, Mikazu; Uchida, Masahiro; Kamei, Gento

    2004-03-01

    To commemorate the 10th anniversary of the ENTRY, a laboratory in JNC Tokai for R and D in the field of geological disposal of radioactive waste, an international workshop was held in JNC Tokai, during the term of Sept 22 to 24, 2003. A technical tour for the Horonobe Underground Research Laboratory site was also done before the workshop, on October 20 to 21, to deepen understanding the background of discussion in the workshop. The workshop contained two sessions. The topic of each session was 1. long-term transition of the near-field and 2. cooperation among the performance assessment, in-situ experiment, and laboratory experiment, respectively. In the session 1, we mainly discussed the thermal-hydrological-mechanical-chemical (THMC) coupled processes for the near-field performance assessment, especially focusing on chemical degradation effects by cement materials and the status of mechanistic understanding radionuclide migration. Silicate dissolution kinetic model, including smectite dissolution in a hyper alkaline solution, was also discussed. Then, we discussed a relevant linkage among laboratory experiments, model (simulation experiment) and database development, in-situ experiment and natural analogue. In the session 2, we discussed 1) methodology for understanding the site based on the surface and boreholes investigations, 2) identification of remained uncertainty after the surface and boreholes investigations, 3) the critical measurement at the surface and boreholes investigations, 4) feedback items from performance assessment to site characterization and 5) required data besides the site investigation. This report contains the minutes of discussion in the workshop. Presented materials were also appended with permission from the speakers. (author)

  4. Frictional sliding in layered rock: laboratory-scale experiments

    International Nuclear Information System (INIS)

    Buescher, B.J.; Perry, K.E. Jr.; Epstein, J.S.

    1996-09-01

    The work is part of the rock mechanics effort for the Yucca Mountain Site Characterization Program. The laboratory-scale experiments are intended to provide high quality data on the mechanical behavior of jointed structures that can be used to validate complex numerical models for rock-mass behavior. Frictional sliding between simulated rock joints was studied using phase shifting moire interferometry. A model, constructed from stacks of machined and sandblasted granite plates, contained a central hole bore normal to the place so that frictional slip would be induced between the plates near the hole under compressive loading. Results show a clear evolution of slip with increasing load. Since the rock was not cycled through loading- unloading, the quantitative differences between the three data sets are probably due to a ''wearing-in'' effect. The highly variable spatial frequency of the data is probably due to the large grain size of the granite and the stochastic frictional processes. An unusual feature of the evolution of slip with increasing load is that as the load gets larger, some plates seem to return to a null position. Figs, 6 refs

  5. The Effect of Chemistry Laboratory Activities on Students' Chemistry Perception and Laboratory Anxiety Levels

    Science.gov (United States)

    Aydogdu, Cemil

    2017-01-01

    Chemistry lesson should be supported with experiments to understand the lecture effectively. For safety laboratory environment and to prevent laboratory accidents; chemical substances' properties, working principles for chemical substances' usage should be learnt. Aim of the present study was to analyze the effect of experiments which depend on…

  6. Characteristics of two types of beam plasma discharge in a laboratory experiment

    International Nuclear Information System (INIS)

    Boswell, R.W.; Kellogg, P.J.

    1983-01-01

    Experiments on the Beam Plasma Discharge (BPD) using an electron beam travelling along a magnetic field have been carried out in a large volume laboratory vacuum chamber. Two different types of BPD have been observed, and scaling laws for varying neutral gas pressure, axial magnetic field, interaction length and electron flux, deduced. The second type of BPD occurs when the beam current is increased well above the threshold for the first type. The transition from the first type to the second, like the ignition of the first, is distinguished by abrupt changes of luminosity, discharge diameter, and wave emission signature

  7. Experiences with fast breeder reactor education in laboratory and short course settings

    International Nuclear Information System (INIS)

    Waltar, A.E.

    1983-01-01

    The breeder reactor industry throughout the world has grown impressively over the last two decades. Despite the uncertainties in some national programs, breeder reactor technology is well established on a global scale. Given the magnitude of this technological undertaking, there has been surprisingly little emphasis on general breeder reactor education - either at the university or laboratory level. Many universities assume the topic too specialized for including appropriate courses in their curriculum - thus leaving students entering the breeder reactor industry to learn almost exclusively from on-the-job experience. The evaluation of four course presentations utilizing visual aids is presented

  8. Controlled laboratory experiments and modeling of vegetative filter strips with shallow water tables

    Science.gov (United States)

    Fox, Garey A.; Muñoz-Carpena, Rafael; Purvis, Rebecca A.

    2018-01-01

    Natural or planted vegetation at the edge of fields or adjacent to streams, also known as vegetative filter strips (VFS), are commonly used as an environmental mitigation practice for runoff pollution and agrochemical spray drift. The VFS position in lowlands near water bodies often implies the presence of a seasonal shallow water table (WT). In spite of its potential importance, there is limited experimental work that systematically studies the effect of shallow WTs on VFS efficacy. Previous research recently coupled a new physically based algorithm describing infiltration into soils bounded by a water table into the VFS numerical overland flow and transport model, VFSMOD, to simulate VFS dynamics under shallow WT conditions. In this study, we tested the performance of the model against laboratory mesoscale data under controlled conditions. A laboratory soil box (1.0 m wide, 2.0 m long, and 0.7 m deep) was used to simulate a VFS and quantify the influence of shallow WTs on runoff. Experiments included planted Bermuda grass on repacked silt loam and sandy loam soils. A series of experiments were performed including a free drainage case (no WT) and a static shallow water table (0.3-0.4 m below ground surface). For each soil type, this research first calibrated VFSMOD to the observed outflow hydrograph for the free drainage experiments to parameterize the soil hydraulic and vegetation parameters, and then evaluated the model based on outflow hydrographs for the shallow WT experiments. This research used several statistical metrics and a new approach based on hypothesis testing of the Nash-Sutcliffe model efficiency coefficient (NSE) to evaluate model performance. The new VFSMOD routines successfully simulated the outflow hydrographs under both free drainage and shallow WT conditions. Statistical metrics considered the model performance valid with greater than 99.5% probability across all scenarios. This research also simulated the shallow water table experiments with

  9. Determination of Mercury in Milk by Cold Vapor Atomic Fluorescence: A Green Analytical Chemistry Laboratory Experiment

    Science.gov (United States)

    Armenta, Sergio; de la Guardia, Miguel

    2011-01-01

    Green analytical chemistry principles were introduced to undergraduate students in a laboratory experiment focused on determining the mercury concentration in cow and goat milk. In addition to traditional goals, such as accuracy, precision, sensitivity, and limits of detection in method selection and development, attention was paid to the…

  10. Iron oxides stimulate microbial monochlorobenzene in situ transformation in constructed wetlands and laboratory systems

    International Nuclear Information System (INIS)

    Schmidt, Marie; Wolfram, Diana; Birkigt, Jan; Ahlheim, Jörg; Paschke, Heidrun; Richnow, Hans-Hermann; Nijenhuis, Ivonne

    2014-01-01

    Natural wetlands are transition zones between anoxic ground and oxic surface water which may enhance the (bio)transformation potential for recalcitrant chloro-organic contaminants due to the unique geochemical conditions and gradients. Monochlorobenzene (MCB) is a frequently detected groundwater contaminant which is toxic and was thought to be persistent under anoxic conditions. Furthermore, to date, no degradation pathways for anoxic MCB removal have been proven in the field. Hence, it is important to investigate MCB biodegradation in the environment, as groundwater is an important drinking water source in many European countries. Therefore, two pilot-scale horizontal subsurface-flow constructed wetlands, planted and unplanted, were used to investigate the processes in situ contributing to the biotransformation of MCB in these gradient systems. The wetlands were fed with anoxic MCB-contaminated groundwater from a nearby aquifer in Bitterfeld, Germany. An overall MCB removal was observed in both wetlands, whereas just 10% of the original MCB inflow concentration was detected in the ponds. In particular in the gravel bed of the planted wetland, MCB removal was highest in summer season with 73 ± 9% compared to the unplanted one with 40 ± 5%. Whereas the MCB concentrations rapidly decreased in the transition zone of unplanted gravel to the pond, a significant MCB removal was already determined in the anoxic gravel bed of the planted system. The investigation of hydro-geochemical parameters revealed that iron and sulphate reduction were relevant redox processes in both wetlands. In parallel, the addition of ferric iron or nitrate stimulated the mineralisation of MCB in laboratory microcosms with anoxic groundwater from the same source, indicating that the potential for anaerobic microbial degradation of MCB is present at the field site. - Highlights: • MCB removal in anoxic gravel bed of a planted and an unplanted constructed wetland was accompanied by iron

  11. Iron oxides stimulate microbial monochlorobenzene in situ transformation in constructed wetlands and laboratory systems

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Marie; Wolfram, Diana; Birkigt, Jan [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Ahlheim, Jörg [Department of Groundwater Remediation, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Paschke, Heidrun [Department of Analytical Chemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Richnow, Hans-Hermann [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Nijenhuis, Ivonne, E-mail: ivonne.nijenhuis@ufz.de [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany)

    2014-02-01

    Natural wetlands are transition zones between anoxic ground and oxic surface water which may enhance the (bio)transformation potential for recalcitrant chloro-organic contaminants due to the unique geochemical conditions and gradients. Monochlorobenzene (MCB) is a frequently detected groundwater contaminant which is toxic and was thought to be persistent under anoxic conditions. Furthermore, to date, no degradation pathways for anoxic MCB removal have been proven in the field. Hence, it is important to investigate MCB biodegradation in the environment, as groundwater is an important drinking water source in many European countries. Therefore, two pilot-scale horizontal subsurface-flow constructed wetlands, planted and unplanted, were used to investigate the processes in situ contributing to the biotransformation of MCB in these gradient systems. The wetlands were fed with anoxic MCB-contaminated groundwater from a nearby aquifer in Bitterfeld, Germany. An overall MCB removal was observed in both wetlands, whereas just 10% of the original MCB inflow concentration was detected in the ponds. In particular in the gravel bed of the planted wetland, MCB removal was highest in summer season with 73 ± 9% compared to the unplanted one with 40 ± 5%. Whereas the MCB concentrations rapidly decreased in the transition zone of unplanted gravel to the pond, a significant MCB removal was already determined in the anoxic gravel bed of the planted system. The investigation of hydro-geochemical parameters revealed that iron and sulphate reduction were relevant redox processes in both wetlands. In parallel, the addition of ferric iron or nitrate stimulated the mineralisation of MCB in laboratory microcosms with anoxic groundwater from the same source, indicating that the potential for anaerobic microbial degradation of MCB is present at the field site. - Highlights: • MCB removal in anoxic gravel bed of a planted and an unplanted constructed wetland was accompanied by iron

  12. Study about the behaviour of fishways in laboratory. Experiments 2009-2010

    International Nuclear Information System (INIS)

    Lara Dominguez, A.; Aramburu Godinez, E.; Berges Acedo, J. A.; Morcillo Alonso, F.; Castillo Blanco, M.

    2011-01-01

    The Hydraulic Laboratory of the Center for Hydro graphic Studies (CEDEX) is carrying out a study about the behaviour of some salmonid and cryprinid fish species in a vertical slot fishways built in the Laboratory, in order to know the relationship between hydraulic and biological parameters and to obtain valid design criteria. Its the first time in our country that fish are been monitored in a fishways using a RFD system, underwater and cenital cameras. First at all, the hydraulic of this typology has been characterised. An experiment protocol has been established to optimize the results. Regarding fish movements in the fishways, on the one hand we have found that fish always rest ascending the pass and, on the other, an influence of the flow on the percentage of fish that ascend the whole pass. Moreover, a tool analyze the efficiency of a fish way model according to biological criteria has been contrasted but it needs to be calibrated with biological variables obtained from native fish species. concerning fish fatigue and effort, studies about physiological parameters in plasma (hematocrit, glucose, cortisol and lactate) have implemented and the results point out the need to increase the studies with physiological parameters in muscle. (Author) 14 refs.

  13. Transcriptome Changes of Escherichia coli, Enterococcus faecalis, and Escherichia coli O157:H7 Laboratory Strains in Response to Photo-Degraded DOM

    Directory of Open Access Journals (Sweden)

    Adelumola Oladeinde

    2018-05-01

    Full Text Available In this study, we investigated gene expression changes in three bacterial strains (Escherichia coli C3000, Escherichia coli O157:H7 B6914, and Enterococcus faecalis ATCC 29212, commonly used as indicators of water quality and as control strains in clinical, food, and water microbiology laboratories. Bacterial transcriptome responses from pure cultures were monitored in microcosms containing water amended with manure-derived dissolved organic matter (DOM, previously exposed to simulated sunlight for 12 h. We used RNA sequencing (RNA-seq and quantitative real-time reverse transcriptase (qRT-PCR to compare differentially expressed temporal transcripts between bacteria incubated in microcosms containing sunlight irradiated and non-irradiated DOM, for up to 24 h. In addition, we used whole genome sequencing simultaneously with RNA-seq to identify single nucleotide variants (SNV acquired in bacterial populations during incubation. These results indicate that E. coli and E. faecalis have different mechanisms for removal of reactive oxygen species (ROS produced from irradiated DOM. They are also able to produce micromolar concentrations of H2O2 from non-irradiated DOM, that should be detrimental to other bacteria present in the environment. Notably, this study provides an assessment of the role of two conjugative plasmids carried by the E. faecalis and highlights the differences in the overall survival dynamics of environmentally-relevant bacteria in the presence of naturally-produced ROS.

  14. Design of a Flexible Hardware Interface for Multiple Remote Electronic practical Experiments of Virtual Laboratory

    Directory of Open Access Journals (Sweden)

    Farah Said

    2012-03-01

    Full Text Available The objective of this work is to present a new design of a Flexible Hardware Interface (FHI based on PID control techniques to use in a virtual laboratory. This flexible hardware interface allows the easy implementation of different and multiple remote electronic practical experiments for undergraduate engineering classes. This interface can be viewed as opened hardware architecture to easily develop simple or complex remote experiments in the electronic domain. The philosophy of the use of this interface can also be expanded to many other domains as optic experiments for instance. It is also demonstrated that software can be developed to enable remote measurements of electronic circuits or systems using only Web site Interface. Using standard browsers (such as Internet explorer, Firefox, Chrome or Safari, different students can have a remote access to different practical experiments at a time.

  15. In-situ experiments on bentonite-based buffer and sealing materials at the Mont Terri rock laboratory (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Wieczorek, K. [Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) GmbH, Braunschweig (Germany); Gaus, I. [National Cooperative for the Disposal of Radioactive Waste (NAGRA), Wettingen (Switzerland); Mayor, J. C. [Empresa Nacional de Residuos Radiactivos SA (ENRESA), Madrid (Spain); and others

    2017-04-15

    Repository concepts in clay or crystalline rock involve bentonite-based buffer or seal systems to provide containment of the waste and limit advective flow. A thorough understanding of buffer and seal evolution is required to make sure the safety functions are fulfilled in the short and long term. Experiments at the real or near-real scale taking into account the interaction with the host rock help to make sure the safety-relevant processes are identified and understood and to show that laboratory-scale findings can be extrapolated to repository scale. Three large-scale experiments on buffer and seal properties performed in recent years at the Mont Terri rock laboratory are presented in this paper: The 1:2 scale HE-E heater experiment which is currently in operation, and the full-scale engineered barrier experiment and the Borehole Seal experiment which have been completed successfully in 2014 and 2012, respectively. All experiments faced considerable difficulties during installation, operation, evaluation or dismantling that required significant effort to overcome. The in situ experiments show that buffer and seal elements can be constructed meeting the expectations raised through small-scale testing. It was, however, also shown that interaction with the host rock caused additional effects in the buffer or seal that could not always be quantified or even anticipated from the experience of small-scale tests (such as re-saturation by pore-water from the rock, interaction with the excavation damaged zone in terms of preferential flow or mechanical effects). This led to the conclusion that testing of the integral system buffer/rock or seal/rock is needed. (authors)

  16. Nutrient cycling Microbial Ecosystems: Assembly, Function and Targeted Design

    Science.gov (United States)

    2017-05-05

    Replicate microcosms created from freshwater pond sediment and water , supplemented by cellulose and sulfate.  Figure 2. Analytical predictions of a ‘2...used as food by other populations [14,15]. On the experimental side, we have used laboratory microcosms, made from pond sediment and water ...different chemical transformations, converting potentially harmful chemicals via a series of intermediates, to harmless waste products. This shuttling of

  17. CIEMAT external dosimetry service: ISO/IEC 17025 accreditation and 3 y of operational experience as an accredited laboratory

    International Nuclear Information System (INIS)

    Romero, A.M.; Rodriguez, R.; Lopez, J.L.; Martin, R.; Benavente, J.F.

    2016-01-01

    In 2008, the CIEMAT Radiation Dosimetry Service decided to implement a quality management system, in accordance with established requirements, in order to achieve ISO/IEC 17025 accreditation. Although the Service comprises the approved individual monitoring services of both external and internal radiation, this paper is specific to the actions taken by the External Dosimetry Service, including personal and environmental dosimetry laboratories, to gain accreditation and the reflections of 3 y of operational experience as an accredited laboratory. (authors)

  18. Bacterial Transport in Heterogeneous Porous Media: Laboratory and Field Experiments

    Science.gov (United States)

    Fuller, M. E.

    2001-12-01

    A fully instrumented research site for examining field-scale bacterial transport has been established on the eastern shore of Virginia. Studies employing intact sediment cores from the South Oyster site have been performed to examine the effects of physical and chemical heterogeneity, to derive transport parameters, and to aid in the selection of bacterial strains for use in field experiments. A variety of innovative methods for tracking bacteria were developed and evaluated under both laboratory and field conditions, providing the tools to detect target cell concentrations in groundwater down to effects of physical and chemical heterogeneity on field-scale bacterial transport. The results of this research not only contribute to the development of more effective bioremediation strategies, but also have implications for a better understanding of bacterial movement in the subsurface as it relates to public health microbiology and general microbial ecology.

  19. Safety Research Experiment Facilities, Idaho National Engineering Laboratory, Idaho. Draft environmental statement

    International Nuclear Information System (INIS)

    1977-01-01

    This environmental statement was prepared in accordance with the National Environmental Policy Act of 1969 (NEPA) in support of the Energy Research and Development Administration's (ERDA) proposal for legislative authorization and appropriations for the Safety Research Experiment Facilities (SAREF) Project. The purpose of the proposed project is to modify some existing facilities and provide a new test facility at the Idaho National Engineering Laboratory (INEL) for conducting fast breeder reactor (FBR) safety experiments. The SAREF Project proposal has been developed after an extensive study which identified the FBR safety research needs requiring in-reactor experiments and which evaluated the capability of various existing and new facilities to meet these needs. The proposed facilities provide for the in-reactor testing of large bundles of prototypical FBR fuel elements under a wide variety of conditions, ranging from those abnormal operating conditions which might be expected to occur during the life of an FBR power plant to the extremely low probability, hypothetical accidents used in the evalution of some design options and in the assessment of the long-term potential risk associated with wide-scale deployment of the FBR

  20. Aespoe Hard Rock Laboratory. Final report of the first stage of the tracer retention understanding experiments

    International Nuclear Information System (INIS)

    Winberg, A.; Andersson, Peter; Hermanson, Jan; Byegaard, Johan

    2000-03-01

    The first stage of the Tracer Retention Understanding Experiments (TRUE) was performed as a SKB funded project. The overall objectives of TRUE are to develop the understanding of radionuclide migration and retention in fractured rock, to evaluate the realism in applied model concepts, and to assess whether the necessary input data to the models can be collected from site characterisation. Further, to evaluate the usefulness and feasibility of different model approaches, and finally to provide in situ data on radionuclide migration and retention. The strive for address with multiple approaches is facilitated through a close collaboration with the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes. The TRUE programme is a staged programme which addresses various scales from laboratory ( 22 Na + 47 Ca 2+ ≅ 85 Sr 2+ 86 Rb + ≅ 133 Ba 2+ The field tracer tests, using essentially the same cocktail of sorbing tracers as in the laboratory, were found to show the same relative sorbtivity as seen in the laboratory. A test using 137 Cs showed that after termination of the test, some 63% of the injected activity remained sorbed in the rock. The interpretation of the in situ tests with sorbing tracers was performed using the LaSAR approach, developed as a part of the TRUE project. In this approach the studied flow path is viewed as a part of an open fracture. Key processes are spatially variable advection and mass transfer. The evaluation shows that laboratory diffusion data are not representative for in situ conditions, and that a close fit between field and modelled breakthrough is obtained only when a parameter group which includes diffusion is enhanced with a factor varying between 32-50 for all tracers and experiments (except for Cs) and 137 for Cs. Our interpretation is that the enhancement is mainly due to higher diffusivity/porosity and higher sorption in the part of the altered rim zone of the feature which is accessible over the time scales