Kinetics and physiological characteristics of autotrophic dentrification by denitrifying sulfur bacteria

2000 ◽  
Vol 42 (3-4) ◽  
pp. 59-68 ◽  
Author(s):  
S.-E. Oh ◽  
K.-S. Kim ◽  
H.-C. Choi ◽  
J. Cho ◽  
I.S. Kim
Keyword(s):  
Gas Production ◽  
Parameter Estimates ◽  
Production Volume ◽  
Autotrophic Denitrification ◽  
Nonlinear Regression Analysis ◽  
Monod Equation ◽  
Sulfur Bacteria ◽  
The Media ◽  
Parameter Values ◽  
Mixotrophic Conditions

To study the kinetics and physiology of autotrophic denitrifying sulfur bacteria, a steady-state anaerobic master culture reactor (MCR) was operated for over six months under a semi-continuous mode and nitrate limiting conditions using nutrient/mineral/buffer (NMB) medium containing thiosulfate and nitrate. Characteristics of the autotropic denitrifier were investigated through the cumulative gas production volume and rate, measured using an anaerobic respirometer, and through the nitrate, nitrite, and sulfate concentrations within the media. The bio-kinetic parameters were obtained based upon the Monod equation using mixed cultures in the MCR. Nonlinear regression analysis was employed using nitrate depletion and biomass production curves. Although this analysis did not yield exact biokinetic parameter estimates, the following ranges for the parameter values were obtained: μmax =0.12-0.2 hr-1; k=0.3-0.4 hr-1; Ks=3-10mg/L; YNO3=0.4-0.5mg Biomass/mg NO3--N. Inhibition of denitrification occurred when the concentrations of NO3--N, and SO42- reached about 660mg/L and 2,000mg/L, respectively. The autotrophic denitrifying sulfur bacteria were observed to be very sensitive to nitrite but relatively tolerant of nitrate, sulfate, and thiosulfate. Under mixotrophic conditions, denitrification by these bacteria occurred autotrophically; even with as high as 2 g COD, autotrophic denitrification was not significantly affected. The optimal pH and temperature for autotrophic denitrification was about 6.5–7.5 and 33–35 °C, respectively.

Modeling of respiratory system impedances in dogs

1987 ◽  
Vol 62 (2) ◽  
pp. 414-420 ◽  
Author(s):  
A. C. Jackson ◽  
K. R. Lutchen
Keyword(s):  
Respiratory System ◽  
Element Model ◽  
Parameter Estimates ◽  
Frequency Range ◽  
Nonlinear Regression Analysis ◽  
Entire Frequency Range ◽  
Frequency Dependent ◽  
Impedance Data ◽  
Parameter Values ◽  
Gas Compressibility

Mechanical impedances between 4 and 64 Hz of the respiratory system in dogs have been reported (A.C. Jackson et al. J. Appl. Physiol. 57: 34–39, 1984) previously by this laboratory. It was observed that resistance (the real part of impedance) decreased slightly with frequency between 4 and 22 Hz then increased considerably with frequency above 22 Hz. In the current study, these impedance data were analyzed using nonlinear regression analysis incorporating several different lumped linear element models. The five-element model of Eyles and Pimmel (IEEE Trans. Biomed. Eng. 28: 313–317, 1981) could only fit data where resistance decreased with frequency. However, when the model was applied to these data the returned parameter estimates were not physiologically realistic. Over the entire frequency range, a significantly improved fit was obtained with the six-element model of DuBois et al. (J. Appl. Physiol. 8: 587–594, 1956), since it could follow the predominate frequency-dependent characteristic that was the increase in resistance. The resulting parameter estimates suggested that the shunt compliance represents alveolar gas compressibility, the central branch represents airways, and the peripheral branch represents lung and chest wall tissues. This six-element model could not fit, with the same set of parameter values, both the frequency-dependent decrease in Rrs and the frequency-dependent increase in resistance. A nine-element model recently proposed by Peslin et al. (J. Appl. Physiol. 39: 523–534, 1975) was capable of fitting both the frequency-dependent decrease and the frequency-dependent increase in resistance. However, the data only between 4 and 64 Hz was not sufficient to consistently determine unique values for all nine parameters.

Integrated Subsurface to Surface Modeling to Assess Reservoir Uncertainty Quantification to A Carbonate Reservoir

2020 ◽  
Author(s):  
A. Chaterine
Keyword(s):  
Uncertainty Quantification ◽  
Gas Production ◽  
Carbonate Reservoir ◽  
Production Volume ◽  
Production Forecast ◽  
Uncertainty Range ◽  
Field Development ◽  
Production Forecasting ◽  
Production Scheme ◽  
Rock Compressibility

This study accommodates subsurface uncertainties analysis and quantifies the effects on surface production volume to propose the optimal future field development. The problem of well productivity is sometimes only viewed from the surface components themselves, where in fact the subsurface component often has a significant effect on these production figures. In order to track the relationship between surface and subsurface, a model that integrates both must be created. The methods covered integrated asset modeling, probability forecasting, uncertainty quantification, sensitivity analysis, and optimization forecast. Subsurface uncertainties examined were : reservoir closure, regional segmentation, fluid contact, and SCAL properties. As the Integrated Asset Modeling is successfully conducted and a matched model is obtained for the gas-producing carbonate reservoir, highlights of the method are the following: 1) Up to ± 75% uncertainty range of reservoir parameters yields various production forecasting scenario using BHP control with the best case obtained is 335 BSCF of gas production and 254.4 MSTB of oil production, 2) SCAL properties and pseudo-faults are the most sensitive subsurface uncertainty that gives major impact to the production scheme, 3) EOS modeling and rock compressibility modeling must be evaluated seriously as those contribute significantly to condensate production and the field’s revenue, and 4) a proposed optimum production scenario for future development of the field with 151.6 BSCF gas and 414.4 MSTB oil that yields a total NPV of 218.7 MMUSD. The approach and methods implemented has been proven to result in more accurate production forecast and reduce the project cost as the effect of uncertainty reduction.

scholarly journals Calibrating a global three-dimensional biogeochemical ocean model (MOPS-1.0)

2017 ◽  
Vol 10 (1) ◽  
pp. 127-154 ◽  
Author(s):  
Iris Kriest ◽  
Volkmar Sauerland ◽  
Samar Khatiwala ◽  
Anand Srivastav ◽  
Andreas Oschlies
Keyword(s):  
Large Scale ◽  
Environmental Changes ◽  
Single Species ◽  
Ocean Model ◽  
Biogeochemical Model ◽  
Parameter Estimates ◽  
Spatial And Temporal Scales ◽  
Ocean Models ◽  
Biogeochemical Tracers ◽  
Parameter Values

Abstract. Global biogeochemical ocean models contain a variety of different biogeochemical components and often much simplified representations of complex dynamical interactions, which are described by many ( ≈ 10 to  ≈ 100) parameters. The values of many of these parameters are empirically difficult to constrain, due to the fact that in the models they represent processes for a range of different groups of organisms at the same time, while even for single species parameter values are often difficult to determine in situ. Therefore, these models are subject to a high level of parametric uncertainty. This may be of consequence for their skill with respect to accurately describing the relevant features of the present ocean, as well as their sensitivity to possible environmental changes. We here present a framework for the calibration of global biogeochemical ocean models on short and long timescales. The framework combines an offline approach for transport of biogeochemical tracers with an estimation of distribution algorithm (Covariance Matrix Adaption Evolution Strategy, CMA-ES). We explore the performance and capability of this framework by five different optimizations of six biogeochemical parameters of a global biogeochemical model, simulated over 3000 years. First, a twin experiment explores the feasibility of this approach. Four optimizations against a climatology of observations of annual mean dissolved nutrients and oxygen determine the extent to which different setups of the optimization influence model fit and parameter estimates. Because the misfit function applied focuses on the large-scale distribution of inorganic biogeochemical tracers, parameters that act on large spatial and temporal scales are determined earliest, and with the least spread. Parameters more closely tied to surface biology, which act on shorter timescales, are more difficult to determine. In particular, the search for optimum zooplankton parameters can benefit from a sound knowledge of maximum and minimum parameter values, leading to a more efficient optimization. It is encouraging that, although the misfit function does not contain any direct information about biogeochemical turnover, the optimized models nevertheless provide a better fit to observed global biogeochemical fluxes.

scholarly journals Escherichia coli O157 infection on Scottish cattle farms: dynamics and control

2010 ◽  
Vol 8 (60) ◽  
pp. 1051-1058 ◽  
Author(s):  
Xu-Sheng Zhang ◽  
Mark E. J. Woolhouse
Keyword(s):  
Escherichia Coli ◽  
Herd Size ◽  
Parameter Estimates ◽  
Control Effort ◽  
Considerable Uncertainty ◽  
Targeted Interventions ◽  
Dynamics And Control ◽  
And Control ◽  
Parameter Values ◽  
Cattle Farms

In this study, we parametrize a stochastic individual-based model of the transmission dynamics of Escherichia coli O157 infection among Scottish cattle farms and use the model to predict the impacts of both targeted and non-targeted interventions. We first generate distributions of model parameter estimates using Markov chain Monte Carlo methods. Despite considerable uncertainty in parameter values, each set of parameter values within the 95th percentile range implies a fairly similar impact of interventions. Interventions that reduce the transmission coefficient and/or increase the recovery rate of infected farms (e.g. via vaccination and biosecurity) are much more effective in reducing the level of infection than reducing cattle movement rates, which improves effectiveness only when the overall control effort is small. Targeted interventions based on farm-level risk factors are more efficient than non-targeted interventions. Herd size is a major determinant of risk of infection, and our simulations confirmed that targeting interventions at farms with the largest herds is almost as effective as targeting based on overall risk. However, because of the striking characteristic that the infection force depends weakly on the number of infected farms, no interventions that are less than 100 per cent effective can eradicate E. coli O157 infection from Scottish cattle farms, implying that eliminating the disease is impractical.

scholarly journals Effects of Irreducible Fluid Saturation and Gas Entry Pressure on Gas Production from Hydrate-Bearing Clayey Silt Sediments by Depressurization

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Xiaolong Ma ◽  
Youhong Sun ◽  
Wei Guo ◽  
Rui Jia ◽  
Bing Li
Keyword(s):  
Water Saturation ◽  
Gas Production ◽  
Production Volume ◽  
Water Production ◽  
Shenhu Area ◽  
Gas Saturation ◽  
Fluid Saturation ◽  
Entry Pressure ◽  
Clayey Silt ◽  
Irreducible Water Saturation

Gas hydrates in the Shenhu area are mainly hosted in clayey silt sediments, which have the relatively high irreducible fluid saturation and gas entry pressure. And then, they will have an impact on gas production from hydrate-bearing clayey silt sediments, which was evaluated by the numerical simulations of SH2 site in Shenhu area in this paper. The results showed that, with the increase in irreducible water saturation and irreducible gas saturation, the amount of water production and gas production was obviously reduced. When the irreducible water saturation increased from 0.10 to 0.50, the cumulative CH4 production volume decreased from 1668799 m3 to 1536262 m3, and the cumulative water production volume dropped from 620304 m3 to 564797 m3, respectively. When the irreducible gas saturation increased from 0.01 to 0.05, the cumulative CH4 production volume dropped from 1812522 m3 to 1622121 m3, and the cumulative water production volume dropped from 672088 m3 to 600617 m3, respectively. In addition, the capillary pressure increased obviously with the increase in gas entry pressure, but the effect on gas production was small and the effect on water production could be negligible. In conclusion, irreducible water and gas saturation had an important effect on the gas production from gas hydrate, whereas the effects of gas entry pressure could be ignored.

scholarly journals Leave-One-Trial-Out (LOTO): A general approach to link single-trial parameters of cognitive models to neural data

2018 ◽  
Author(s):  
Sebastian Gluth ◽  
Nachshon Meiran
Keyword(s):  
Cognitive Model ◽  
Parameter Estimates ◽  
Model Parameters ◽  
Single Trial ◽  
Neural Data ◽  
Brain Signals ◽  
Complete Dataset ◽  
Advance Research ◽  
The Difference ◽  
Parameter Values

AbstractIt has become a key goal of model-based neuroscience to estimate trial-by-trial fluctuations of cognitive model parameters for linking these fluctuations to brain signals. However, previously developed methods were limited by being difficulty to implement, time-consuming, or model-specific. Here, we propose an easy, efficient and general approach to estimating trial-wise changes in parameters: Leave-One-Trial-Out (LOTO). The rationale behind LOTO is that the difference between the parameter estimates for the complete dataset and for the dataset with one omitted trial reflects the parameter value in the omitted trial. We show that LOTO is superior to estimating parameter values from single trials and compare it to previously proposed approaches. Furthermore, the method allows distinguishing true variability in a parameter from noise and from variability in other parameters. In our view, the practicability and generality of LOTO will advance research on tracking fluctuations in latent cognitive variables and linking them to neural data.

scholarly journals Valorization of dietary lemon pomace waste to enhance lucerne silage composition and quality characteristics, and ruminal biogas production and fermentation

2021 ◽  
Author(s):  
Maghsoud Besharati ◽  
Valiollah Palangi ◽  
Zabihollah Nemati ◽  
Rashid Safari ◽  
Abdelfattah Z. M. Salem
Keyword(s):  
Dry Matter ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Bacterial Species ◽  
Gas Production ◽  
Matter Content ◽  
Dry Matter Content ◽  
Production Volume ◽  
Randomized Design

Abstract The purpose of this study was to investigate the effect of adding various levels of waste sour lemon pomace to lucerne on the properties and ruminal gas production of silage. Levels of 0 (Control), 25 (L1), 50 (L2), 75 (L3), and 100 (L4) % lemon pomace were replaced by lucerne for silage preparation and silenced for 60 days. The experiment was conducted in a completely randomized design with three replications (3 silos per treatment). After opening the silos, pH and dry matter were measured immediately, and the dried samples were kept at -20 until further tests. The silage pH decreased with the addition of lemon pomace compared to the control (p < 0.05). Total silage volatile fatty acids and dry matter content increased with adding lemon pomace. The results of gas production also showed that lemon pomace increased the in vitro gas production volume. Adding lemon pomace to lucerne silage due to the high pectin content in these agricultural wastes caused a rapid decrease of silage pH and an acidic environment. It prevented the growth of non-beneficial bacterial species. The obtained data showed that waste sour lemon has a good potential to use as a livestock feedstuff that can be useful in reducing the cost of ruminant production and preventing environmental pollution.

scholarly journals Numerical Investigation on Gas Production Performance in Methane Hydrate of Multilateral Well under Depressurization in Krishna-Godavari Basin

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Xin Xin ◽  
Si Li ◽  
Tianfu Xu ◽  
Yilong Yuan
Keyword(s):  
Production Rate ◽  
Production Efficiency ◽  
Gas Production ◽  
Geometric Parameters ◽  
Production Performance ◽  
Production Volume ◽  
Hydrate Decomposition ◽  
Single Well ◽  
Influence Radius ◽  
Lateral Branches

Nature gas hydrate is a new kind of clean and potential resources. Depressurization is regarded as the most effective and promising hydrate production technology. One of the key points in improving the gas production effectiveness of depressurization is whether pressure gradient could transmit in strata effectively. Single well method is widely used in hydrate exploit which is circumscribed in expanding the range of hydrate decomposition. Consequently, the well structure and production strategy needs to be optimized for improving the gas recovery efficiency. The multilateral well technology is proposed for increasing the gas productivity of the reservoir greatly by increasing the multilateral branches. In this paper, we established a numerical simulation model based on the geological data NGHP-02-16 site in the KG basin to evaluate the gas production performance of the reservoir by depressurization. It mainly focuses on investigating the gas production performance of multilateral wells with different combinations of geometric parameters of multilateral branches, such as different dip angle, numbers, and spacing of lateral branches. The result shows that the multilateral well method can effectively increase the gas production rate with the water production rate increase slightly. The cumulative gas production volume of a single vertical well is about 2.85 × 10 6   m 3 , while it is of the multilateral well can reach 4.18 × 10 6   m 3 during a one-year production. The well interference, the effective influence radius of each multilateral branch, and the vertical depth of the lateral branch are the main factors which affect the gas production efficiency of the multilateral well. The optimization of the geometric parameters of lateral should consider not only the gas production efficiency but also the well interference between the lateral branches.

scholarly journals Stainless Steel Cyclic Voltammograms in Dioscorea Opposita Flour Media

2021 ◽  
Vol 6 (3) ◽  
pp. 535-542
Author(s):  
Isana Supiah Yosephine Louise ◽  
Siti Marwati ◽  
S. Sulistyani ◽  
Heru Pratomo Al ◽  
Felix Arie Setiawan
Keyword(s):  
Stainless Steel ◽  
Energy Consumption ◽  
Water Electrolysis ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Cyclic Voltammograms ◽  
Electrolysis Process ◽  
Dioscorea Opposita ◽  
The Media ◽  
The Cost

Improving the efficiency of hydrogen gas production in the water electrolysis process draws great attention from many scholars. To improve the efficiency of the process and reduction in the cost, stainless steel has been widely implemented in the industrial water electrolysis process. Electrolyte modification is also one of the methods to improve the water electrolysis process. The study used Dioscorea opposita tuber flour as a media addition in an alkaline solution. The efficiency of water electrolysis was evaluated by cyclic voltammetry. The result showed that the activity of the electrode and energy consumption were increased with values of 29 and 23%, respectively, by adding 3 g of the media. However, no media addition showed the lowest energy consumption regarding overpotential value. In general, the Dioscorea opposita tuber flour tends to cover the electrode and reduce the activity. Moreover, the utilization of wastewater from Dioscorea opposita flour industry is still beneficial to produce hydrogen gas instead of using freshwater.

scholarly journals Nitrite oxidation by phototrophic bacteria of Chlorobium, Thiocapsa and Lamprocystis genera under the influence of inorganic pollutants

2021 ◽  
Vol 29 (1) ◽  
pp. 39-46
Author(s):  
O. M. Moroz ◽  
G. I. Zvir ◽  
S. O. Hnatush
Keyword(s):  
Biomass Accumulation ◽  
Purple Sulfur Bacteria ◽  
Inorganic Pollutants ◽  
Sulfate Ions ◽  
Sulfur Bacteria ◽  
Physiological Properties ◽  
Dry Cell Weight ◽  
The Media ◽  
Dry Cell ◽  
In Cells

Pollutants of inorganic nature (acids, alkalis, mineral salts of different composition, metals) change the course of biological processes of environmental purification, but their influence on the physiological properties of phototrophic sulfur bacteria has not been studied enough. The usage of nitrite ions as an electron donor of anoxygenic photosynthesis by cells of phototrophic green and purple sulfur bacteria Chlorobium limicola IMV K-8, Thiocapsa sp. Ya-2003 and Lamprocystis sp. Ya-2003, isolated from Yavorivske Lake, under the influence of the most widespread inorganic pollutants – hydro- and dihydrophosphates, sulfates, chlorides and chlorates, has been studied. It is shown that KH2PO4, K2HPO4, Na2SO4, NaCl and KClO3, present in the van Niel medium with 4.2 mM NaNO2 at concentrations that are 0.5, 1.0, 2.0, 3.0, 4.0 times different from the maximum permissible concentrations (MPC), influenced the biomass accumulation and nitrite ions oxidation by phototrophic green and purple sulfur bacteria. In media with hydro- and dihydrophosphate ions at concentrations 4.0 times higher than the MPC, inhibition of bacterial growth was up to 1.7 times lower than in the control. The biomass accumulation by bacteria in media with chloride and chlorate ions at concentrations 3.0–4.0 times higher than MPC was 2.0–2.8 times lower compared to the control. In the medium with Na2SO4 at concentrations 2.0–4.0 times higher than MPC, the biomass was 2.0–4.0 times lower than in the control. Nitrites’ oxidation by all strains in the media with the studied pollutants was slowed down. The residual content of nitrite ions in media with hydro- and dihydrophosphate, chloride and chlorate ions at their concentrations 4.0 times higher than MPC, exceeded the NO2– content in the control variants up to 1.7 times. If in the medium without pollutants the cells of C. limicola IMV K-8, Thiocapsa sp. Ya-2003 and Lamprocystis sp. Ya-2003 strains oxidized 72.7%, 72.2% and 71.4%, respectively, of nitrite ions present in the medium, then in the medium with sulfate ions at concentration 4.0 times higher than the MPC, bacteria oxidized nitrite ions only at 39.6%, 34.4% and 27.0%, respectively. Oxidation of a lower quantity of nitrites by phototrophic bacteria in the media with inorganic pollutants led to the production by them of a lower quantity of nitrates. The content of NO3– in the media with hydro-, dihydrophosphate and chlorate ions at all concentrations was up to 1.9 times lower than in the control. In media with sulfate ions at concentrations 2.0–4.0 times higher than MPC and chloride at concentration 4.0 times higher than MPC, the content of nitrate ions was 2.1–4.3 and 2.0 times, respectively, lower than in the control variants. Inorganic pollutants stimulated the synthesis of intracellular carbohydrates in C. limicola IMV K-8. If the content of intracellular glucose in cells grown in the medium without pollutants was 10.3 mg/g dry cell weight, then in cells grown in media with K2HPO4, KH2PO4, Na2SO4, NaCl and KClO3 at concentrations 4.0 times higher than MPC, its content increased by 12.2%, 10.7%, 51.6%, 17.1% and 35.9%, respectively. The glycogen content in the cells grown in the medium without pollutants was 45.1 mg/g dry cell weight. Hydro- and dihydrophosphate, chloride and chlorate ions at concentrations 4.0 times higher than MPC stimulated glycogen synthesis in cells by 47.5%, 57.6%, 67.4% and 74.6%, respectively. The glycogen content in cells grown in the medium with Na2SO4 at concentrations 3.0 and 4.0 times higher than MPC increased by 102.9% and 107.5%, respectively. Therefore, it is established that pollutants of inorganic nature affect the physiological properties of photosynthetic sulfur bacteria and thus change the course of biological processes of environment purification, in particular, from nitrite ions.

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