Modeling Studies on Microbial Effects on Groundwater Chemistry

2006 ◽  
Vol 985 ◽  
Author(s):  
Yoshikatsu Tochigi ◽  
Hideki Yoshikawa ◽  
Mikazu Yui
Keyword(s):  
Redox Potential ◽  
Microbial Activity ◽  
Specific Activity ◽  
Measurement Techniques ◽  
Groundwater Chemistry ◽  
Sensitivity Analyses ◽  
Numerical Code ◽  
Sulfate Reducing ◽  
Geochemical Parameters ◽  
Microbial Effects

AbstractThe overall goal of this project is to develop a model to predict microbial effects on the performance of a high-level radioactive waste (HLW) repository. As a first step, the effects of microbes on groundwater chemistry have been evaluated with the numerical code 'MINT', using data collected from the borehole HDB-6 in the Horonobe underground research laboratory (URL) in Japan. The MINT code models biochemistry and geochemical equilibrium, with consideration of transport of solute and microbial activity. The MINT code simulates the activities of 6 major groups of microbes, classified by their metabolism as 'aerobic', 'denitrifying', 'manganese reducing', 'iron reducing', 'sulfate reducing' and 'methanogenic'. The specific activity of each of these groups will depend on the redox potential (Eh) of the groundwater.Sensitivity analyses were performed to investigate the consequences of changes in groundwater composition on the effects of microbial activity. This indicates that the activities of Sulfate Reducing Bacteria (SRB) and methanogens are relatively high. The concentration of dissolved methane produced by such microbial activity is seen to be influenced by sulfate concentration. Based on the observed data from Horonobe URL, the concentration in oxygen is relatively high and the activity of denitrifying bacteria is the highest of the major 6 groups of microbes. This can, however, be attributable to chemical / microbial contamination of the groundwater during sampling. The modeling results indicate that the concentration of dissolved oxygen and nitrate ion should be quickly reduced by microbial metabolism, reducing the redox potential to a level low enough for active methanogenesis to commence. Such assessment can be important to evaluate the reliability of sampling and measurement techniques for sensitive geochemical parameters in general - and microbiology in particular.

Construction of Microbial Kinetics Database for PA of HLW disposal

2014 ◽  
Vol 1665 ◽  
pp. 47-53
Author(s):  
Hideki Yoshikawa ◽  
Tsuyoshi Ito ◽  
Kotaro Ise ◽  
Yoshito Sasaki
Keyword(s):  
Chemical Species ◽  
Literature Survey ◽  
Sensitivity Analyses ◽  
Sulfate Reducing ◽  
Microbial Kinetics ◽  
Acetogenic Bacteria ◽  
Deep Underground ◽  
Waste Repository ◽  
High Level ◽  
Microbial Effects

ABSTRACTTo evaluate a change of chemical species of groundwater composition by the metabolism of microbes, which will be introduced to deep underground from the surface and be in a deep underground, is important for the discussion of the microbial effects on the performance assessment of the high-level radioactive waste repository. The purpose of this study is to develop of a microbial kinetics database to evaluate their activities in the deep underground environment.Some microbial metabolism data were collected and constructed their kinetics database for aerobic, denitrifying, manganese reducing, iron reducing, sulfate reducing, methanogenic and acetogenic bacteria to evaluate above groundwater chemistry. About 1260 data were selected by literature survey for some journals and books published from 1960s and summarized in this microbial kinetics database. Some sensitivity analyses were performed for some parameter of metabolism of microbes.

A new method for monitoring the redox potential of fuel salt based on the deposition of 95Nb on Hastelloy C276

2021 ◽  
Vol 109 (5) ◽  
pp. 357-365
Author(s):  
Zhiqiang Cheng ◽  
Zhongqi Zhao ◽  
Junxia Geng ◽  
Xiaohe Wang ◽  
Jifeng Hu ◽  
...  
Keyword(s):  
Redox Potential ◽  
Molten Salt ◽  
Specific Activity ◽  
Chemical Reduction ◽  
Quantitative Approach ◽  
Experimental Results ◽  
New Method ◽  
Molten Salt Reactor ◽  
Fuel Salt ◽  
Well Correlation

Abstract To develop the application of 95Nb as an indicator of redox potential for fuel salt in molten salt reactor (MSR), the specific activity of 95Nb in FLiBe salt and its deposition of 95Nb on Hastelloy C276 have been studied. Experimental results indicated that the amount of 95Nb deposited on Hastelloy C276 resulted from its chemical reduction exhibited a positive correlation with the decrease of 95Nb activity in FLiBe salt and the relative deposition coefficient of 95Nb to 103Ru appeared a well correlation with 95Nb activity in FLiBe salt. Both correlations implied that the measurement of 95Nb activity deposited on Hastelloy C276 specimen might provide a quantitative approach for monitoring the redox potential of fuel salt in MSR.

scholarly journals Detecting Redox Potentials Using Porous Boron Nitride/ATP-DNA Aptamer/Methylene Blue Biosensor to Monitor Microbial Activities

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 83
Author(s):  
Kai Guo ◽  
Zirui Song ◽  
Gaoxing Wang ◽  
Chengchun Tang
Keyword(s):  
Methylene Blue ◽  
Microbial Community ◽  
Boron Nitride ◽  
Redox Potential ◽  
Microbial Activity ◽  
Potential Change ◽  
Dna Aptamer ◽  
Redox Potentials ◽  
Microplate Reader

Microbial activity has gained attention because of its impact on the environment and the quality of people’s lives. Most of today’s methods, which include genome sequencing and electrochemistry, are costly and difficult to manage. Our group proposed a method using the redox potential change to detect microbial activity, which is rooted in the concept that metabolic activity can change the redox potential of a microbial community. The redox potential change was captured by a biosensor consisting of porous boron nitride, ATP-DNA aptamer, and methylene blue as the fluorophore. This assembly can switch on or off when there is a redox potential change, and this change leads to a fluorescence change that can be examined using a multipurpose microplate reader. The results show that this biosensor can detect microbial community changes when its composition is changed or toxic metals are ingested.

scholarly journals Purification and Characterization of an Iron Superoxide Dismutase and a Catalase from the Sulfate-Reducing BacteriumDesulfovibrio gigas

2000 ◽  
Vol 182 (3) ◽  
pp. 796-804 ◽  
Author(s):  
Wagner G. Dos Santos ◽  
Isabel Pacheco ◽  
Ming-Yih Liu ◽  
Miguel Teixeira ◽  
António V. Xavier ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
High Spin ◽  
Specific Activity ◽  
Ligand Field ◽  
Strictly Anaerobic ◽  
Oxygen Utilization ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Sulfate Reducing ◽  
Link Type

ABSTRACT The iron-containing superoxide dismutase (FeSOD; EC 1.15.1.1 ) and catalase (EC 1.11.1.6 ) enzymes constitutively expressed by the strictly anaerobic bacterium Desulfovibrio gigas were purified and characterized. The FeSOD, isolated as a homodimer of 22-kDa subunits, has a specific activity of 1,900 U/mg and exhibits an electron paramagnetic resonance (EPR) spectrum characteristic of high-spin ferric iron in a rhombically distorted ligand field. Like other FeSODs from different organisms, D. gigas FeSOD is sensitive to H2O2 and azide but not to cyanide. The N-terminal amino acid sequence shows a high degree of homology with other SODs from different sources. On the other hand, D. gigas catalase has an estimated molecular mass of 186 ± 8 kDa, consisting of three subunits of 61 kDa, and shows no peroxidase activity. This enzyme is very sensitive to H2O2and cyanide and only slightly sensitive to sulfide. The native enzyme contains one heme per molecule and exhibits a characteristic high-spin ferric-heme EPR spectrum (g y,x = 6.4, 5.4); it has a specific activity of 4,200 U/mg, which is unusually low for this class of enzyme. The importance of these two enzymes in the context of oxygen utilization by this anaerobic organism is discussed.

Source and Purity of Factor VIII Products As Risk Factors for Inhibitor Development In Previously Untreated Patients with Severe Hemophilia A

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 25-25
Author(s):  
Maria Elisa Mancuso ◽  
Pier Mannuccio Mannucci ◽  
Angiola Rocino ◽  
Isabella Garagiola ◽  
Annarita Tagliaferri ◽  
...  
Keyword(s):  
Risk Factors ◽  
Factor Viii ◽  
High Purity ◽  
Hemophilia A ◽  
Conflicts Of Interest ◽  
Specific Activity ◽  
Sensitivity Analyses ◽  
Severe Hemophilia ◽  
Inhibitor Development ◽  
Treatment Data

Abstract Abstract 25 Background: Inhibitor development is influenced by several genetic and environmental factors and the type of factor VIII (FVIII) products may play a role. Methods: We designed a cohort study whose novelty resides in the classification of products not only according to the plasmatic (pdFVIII) or recombinant (rFVIII) source of FVIII but also to the degree of purity expressed as FVIII specific activity per mg of protein. The role of FVIII product as risk factor for inhibitor development was evaluated in a multivariate model adjusting for potential confounders (i.e. age at first FVIII exposure, intensive treatment and prophylaxis). Cumulative incidences of all and high-responding inhibitors were calculated for the whole cohort of 721 patients with severe and moderate hemophilia A followed-up in 3 Italian Hemophilia Centers. Detailed treatment data from the first FVIII infusion up to inhibitor development or 150 exposure days were available for 377 patients and in this group of patients risk factors for inhibitor development including the type of FVIII product and its degree of purity (i.e. low/intermediate-, high-purity pdFVIII and rFVIII) were analysed. Results: The overall cumulative incidence of inhibitors was 22% (n=160; 130 high-responders, 18%) and it was lower in patients first treated with pdFVIII (107/586, 18%) than in those treated with rFVIII (53/135, 39%). Similar results were obtained by evaluating only high-responding inhibitors and patients with severe hemophilia. The adjusted hazard ratio of inhibitor development was 4.9 with rFVIII and 2.0 with high-purity pdFVIII (95%CI: 2.9–8.3 and 1.1–4.0), taking as reference low/intermediate-purity pdFVIII. There was no difference in the frequency of inhibitor testing between treatment groups. Sensitivity analyses - in patients who never switched product type, previously untreated patients, those treated on-demand and those with high-risk F8 mutations - confirmed an increased inhibitor risk in patients first treated with rFVIII or high-purity pdFVIII than in those treated with low/intermediate-purity pdFVIII. In fact, in all the aforementioned subgroups by multivariate analysis the risk of inhibitor development was invariably 3- to 6-fold higher in patients first treated with rFVIII than in those first treated with pdFVIII, and similar results were obtained for both all inhibitors and high-responding inhibitors. Conclusions: This study shows that the degree of purity of FVIII products influences inhibitor development independently from other risk factors, and emphasizes that differences exist also within pdFVIII products. Disclosures: No relevant conflicts of interest to declare.

Experimental Investigations on Cooling Air Ejection at a Straight Turbine Cascade Using PIV and QLS

2011 ◽  
Author(s):  
Oliver Freund ◽  
Hans-Juergen Rehder ◽  
Philipp Schaefer ◽  
Ingo Roehle
Keyword(s):  
Measurement Techniques ◽  
Co2 Concentration ◽  
Light Sheet ◽  
Numerical Code ◽  
Experimental Investigations ◽  
Test Bed ◽  
Air Concentration ◽  
Trailing Edge ◽  
Air Ejection ◽  
Cooling Air

Due to the high turbine inlet temperatures in modern aircraft engines the adoption of several cooling techniques in the first turbine blade rows is state of the art. For this reason the influence of cooling air ejection on the main flow is in the interest of scientists. In this paper experimental and numerical investigations on the trailing edge cooling air ejection at a stator profile are presented. All measurements are performed at the Straight Cascade Wind tunnel Go¨ttingen. To verify the influence of the cooling air flow on the flow field, the velocity field is measured by Particle Image Velocimetry (PIV). The development of the cooling air concentration is analyzed by utilizing the Quantitative Light Sheet (QLS) technique. For validation purposes the QLS results are compared to CO2 concentration measurements. Both measurement techniques are in good agreement with each other. One of the most important advantages of PIV and QLS is the possibility of combining them at the same test bed due to the identical experimental setup. The experimental investigations are supported by numerical simulations based on the numerical code TRACE. Both the numerical results as well as the experimental results prove the reduction of the trailing edge shock by increasing the coolant mass flow ratio.

Study on the IMO Second Generation Intact Stability Criteria of Surf-riding/Broaching Failure Mode

2015 ◽  
Author(s):  
Peiyuan Feng ◽  
Xingrong Shen ◽  
Sheming Fan
Keyword(s):  
Failure Mode ◽  
Model Experiment ◽  
Ship Design ◽  
Sensitivity Analyses ◽  
Numerical Code ◽  
Stability Criteria ◽  
Intact Stability ◽  
Free Running ◽  
Surf Riding ◽  
Potential Impact

A series of investigations on the vulnerability criteria for the surf-riding/broaching stability failure mode is conducted. First and foremost, free running model experiment of a purse seiner in severe following waves is performed to demonstrate the fatalness of surf-riding/broaching. The latest IMO proposal to assess broaching stability failure mode is then studied in detail. A numerical code with user interface is developed to facilitate sensitivity analyses and sample ship calculations. The appropriateness of the proposal is analyzed and its potential impact on ship design is discussed.

MICROBIAL ACTIVITY IN THE PEERLESS JENNY KING SULFATE REDUCING BIOREACTOR SYSTEM

2007 ◽  
Vol 2007 (1) ◽  
pp. 109-122 ◽  
Author(s):  
Emma Buccambuso ◽  
Linda Figueroa ◽  
Jim Ranvile ◽  
Thomas Wildeman ◽  
David Reisman
Keyword(s):  
Microbial Activity ◽  
Sulfate Reducing ◽  
Bioreactor System ◽  
Sulfate Reducing Bioreactor

Organic Carbon Utilisation by Iron(II)-Oxidising Bacteria Sulfobacillus thermosulfidooxidans and Alicyclobacillus Strain FP1 that Inhabit Copper Sulfide Leaching Heaps

2015 ◽  
Vol 1130 ◽  
pp. 218-221 ◽  
Author(s):  
Denis W. Shiers ◽  
David M. Collinson ◽  
Helen R. Watling
Keyword(s):  
Microbial Activity ◽  
Yeast Extract ◽  
Copper Sulfide ◽  
Measurement Techniques ◽  
Organic Substrates ◽  
Solution Ph ◽  
Acid Consumption ◽  
Culture Independent ◽  
Carbon Utilisation ◽  
Monitoring And Measurement

Strains ofSulfobacillus (S.)andAlicyclobacillusspecies have been identified/detected in managed bioleaching heaps and agitated tanks using culture-dependent and culture-independent methods.S thermosulfidooxidansoxidises both iron(II) and reduced inorganic sulfur compounds (RISC). Several strains were isolated from a copper sulfide heap in North Western Australia.Alicyclobacillusstrain FP1 (FP1) was also isolated from the heap and oxidises iron(II) but not RISC. However, the species exhibit differentiating characteristics during growth on D-glucose, which has been explored using a suite of monitoring and measurement techniques. As examples, a growth factor (yeast extract) is essential for FP1 but not forS. thermosulfidooxidans, although yeast extract is beneficial to the latter. FP1 grows well on glucose, compared with the poor-to-no growth ofS. thermosulfidooxidanson the substrate. Solution pH strongly influences the activity of both species when grown on organic substrates, suggesting a pivotal role for solution acidity in the growth and activity of heterotrophs or mixotrophs in heap leach systems. This research forms part of an ongoing development of a data base with which to interpret the impacts of leaching conditions in heaps on microbial activity without having to disrupt metal production by invasive sampling campaigns. The insights gained will assist in understanding the effects that changing conditions in heaps due to acid consumption and/or increased element concentrations in process water may have on microbial activity.

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