Mathematical modeling of trichloroethylene (TCE) degradation in membrane-attached biofilms

2000 ◽  
Vol 41 (4-5) ◽  
pp. 239-244 ◽  
Author(s):  
D.R. Noguera ◽  
G. Pizarro ◽  
L.W. Clapp
Keyword(s):  
Mathematical Modeling ◽  
Gas Phase ◽  
Competitive Inhibition ◽  
Cell Concentration ◽  
Biofilm Reactor ◽  
Membrane Thickness ◽  
Back Diffusion ◽  
Simulation Results ◽  
Inactive Cell ◽  
Tce Degradation

A mathematical model for the counter-diffusional membrane-attached methanotrophic biofilm reactor was developed. The model included competitive inhibition between trichloroethylene (TCE) and methane, production of inactive cells by TCE byproduct toxicity, and biomass detachment as a function of inactive cell concentration. Simulation results indicated that the optimum oxygen to methane ratio was dependent on the biofilm and the membrane thickness. Furthermore, the model confirmed experimental observations that the efficiency of the process is not limited by competitive inhibition or substrates mass transfer, but by the back-diffusion of TCE through the membrane and the consequent TCE accumulation in the gas phase.

Methods of Mathematical Modeling of the Leaching Process of Cobalt-Containing Solutions

2021 ◽  
Vol 316 ◽  
pp. 661-666
Author(s):  
Nataliya V. Mokrova
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Chemical Kinetics ◽  
Group Method ◽  
Data Handling ◽  
Multistage Processes ◽  
Leaching Process ◽  
Proposed Model ◽  
Simulation Results ◽  
The Mathematical Model

Current cobalt processing practices are described. This article discusses the advantages of the group argument accounting method for mathematical modeling of the leaching process of cobalt solutions. Identification of the mathematical model of the cascade of reactors of cobalt-producing is presented. Group method of data handling is allowing: to eliminate the need to calculate quantities of chemical kinetics; to get the opportunity to take into account the results of mixed experiments; to exclude the influence of random interference on the simulation results. The proposed model confirms the capabilities of the group method of data handling for describing multistage processes.

scholarly journals Population Behavior in the Mathematical Model of the Spread of COVID19 Type SEIRS

2021 ◽  
Vol 6 (2) ◽  
pp. 83-88
Author(s):  
Asmaidi As Med ◽  
Resky Rusnanda
Keyword(s):  
Mathematical Modeling ◽  
Numerical Simulation ◽  
Mathematical Model ◽  
Everyday Life ◽  
Applied Mathematics ◽  
Living Things ◽  
Simulation Results ◽  
Parameter Values ◽  
The Mathematical Model ◽  
Disease Free

Mathematical modeling utilized to simplify real phenomena that occur in everyday life. Mathematical modeling is popular to modeling the case of the spread of disease in an area, the growth of living things, and social behavior in everyday life and so on. This type of research is included in the study of theoretical and applied mathematics. The research steps carried out include 1) constructing a mathematical model type SEIRS, 2) analysis on the SEIRS type mathematical model by using parameter values for conditions 1and , 3) Numerical simulation to see the behavior of the population in the model, and 4) to conclude the results of the numerical simulation of the SEIRS type mathematical model. The simulation results show that the model stabilized in disease free quilibrium for the condition  and stabilized in endemic equilibrium for the condition .

Mathematical modeling of biological tissues electrical conductivity based on the ion electrodiffusion equations

2021 ◽  
Author(s):  
N.V. Kovalenko ◽  
K.V. Sovin ◽  
O.A. Ryabushkin
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Electrical Properties ◽  
Biological Tissue ◽  
Physiological State ◽  
Biological Tissues ◽  
Radiation Heating ◽  
Tissue Degradation ◽  
Simulation Results ◽  
Electrical Properties Of Tissues

Problem formulating. The vital processes of biological tissues are closely related to their electrical properties. An important task is to create a physical and mathematical model that will link the electrical properties of tissues to their physiological state. Goal. Construction of a model of biological tissue electrical properties based on the equations of ion electrodiffusion. Result. The paper presents the model of biological tissue electrical properties based on the ion electrodiffusion equations, and compares the simulation results with the experimental results presented in the literature. Practical meaning. The presented model can be used to describe processes occurring in tissue at the level of concentration and conductivity of ions in individual cells and cell membranes. In particular, the process of tissue degradation during laser radiation heating can be described.

Activity, structure, and stratification of membrane-attached methanotrophic biofilms cometabolically degrading trichloroethylene

1999 ◽  
Vol 39 (7) ◽  
pp. 153-161 ◽  
Author(s):  
Lee W. Clapp ◽  
John M. Regan ◽  
Firdaus Ali ◽  
Jack D. Newman ◽  
Jae K. Park ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pure Culture ◽  
Competitive Inhibition ◽  
Biofilm Reactor ◽  
Utilization Rate ◽  
Negative Effects ◽  
Loading Rates ◽  
Activity Structure ◽  
Serine Pathway ◽  
Biofilm Development

A membrane-attached methanotrophic biofilm reactor was developed for the cometabolic degradation of trichloroethylene (TCE). In this reactor, CH4 and O2 are supplied to the interior of the biofilm through the membrane, while TCE-contaminated water is supplied to the exterior, creating a “counter-diffusional” effect that minimizes competitive inhibition between TCE and CH4. In addition, this novel design provides 100% CH4 and O2 transfer efficiencies, promotes the development of a thick biofilm, and minimizes the negative effects of TCE byproduct toxicity. The reactor sustained 80-90% TCE removals at TCE loading rates ranging from 100-320 μmol/m2/d. Chloride mass balances demonstrated that 60-80% of the TCE removed was mineralized. The maximum TCE transformation yield was 1.8 mmol of TCE removed per mole of CH4 utilized, although higher transformation yields are expected at higher TCE loading rates. The CH4 utilization rate was 0.20 mol/m2/d. Scanning electron microscopy (SEM) revealed a dense biofilm with a thickness of at least 400 μm. SEM and transmission electron microscopy (TEM) analyses indicated that the “holdfast” material associated with rosette formation in planktonic Methylosinus trichosporium OB3b (M.t. OB3b) cells might also contribute to pure-culture biofilm development. In addition, fimbriae-like structures not commonly associated with methanotrophic bacteria were observed in pure-culture M.t. OB3b biofilms. Finally, fluorescent in situ hybridization (FISH) analyses showed the presence of discrete microcolonies of serine-pathway methanotrophs within mixed-culture biofilms.

The Tapping Machine Mathematical Modeling Simulation Study

2013 ◽  
Vol 373-375 ◽  
pp. 2073-2077
Author(s):  
Bing Hua Jiang ◽  
Li Fang ◽  
Hang Biao Guo
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Blast Furnace ◽  
Rotation Speed ◽  
Pulse Signal ◽  
Structural Features ◽  
Machine Model ◽  
Modeling Simulation ◽  
Impact Attenuation ◽  
Simulation Results

Based on the tapping machines special structural features and practices, from both directions of rotation and impact established the tapping machine mechanism rotating borer and impact dynamic mathematical model, analysed the effect of different tapping machines parameters on the model itself, simulated the model with inputting wide pulse signal, the simulation results show that: firstly, the tapping machine model established in this paper is reasonable; secondly, increase the damping coefficient of the blast furnace, the tapping machines rotating borer rotation speed and impact attenuation speed decrease.

RANS Modeling in Gas-Solid Particle Vertical Flow (Keynote)

2005 ◽  
Author(s):  
Alexander I. Kartushinsky ◽  
Efstathios E. Michaelides
Keyword(s):  
Mathematical Modeling ◽  
Gas Phase ◽  
Solid Particle ◽  
Pipe Flow ◽  
Original Model ◽  
Particle Flow ◽  
Dispersed Phase ◽  
Vertical Flow ◽  
Rans Modeling ◽  
Phase Motion

Results from the mathematical modeling of gas-solid particle flow in an upward pipe flow performed in the framework of RANS are presented. The aim of the study is to implement an original model of closure for the transport equations of dispersed phase along with particles involvement into the turbulence motion into further developed the modeling description using the RANS approach. It allows the retention of the diffusive terms in both streamwise and radial directions. The numerical simulations show that the RANS method captures the main characteristics and overall behavior of the particle and gas-phase motion in the pipe.

The Mechanical Improve Design and Simulation Analysis of Loom’s Let-Off System

2012 ◽  
Vol 443-444 ◽  
pp. 1078-1083
Author(s):  
Jian Cheng Yang ◽  
Xin Rong Li ◽  
Yong Li Zhao ◽  
Guan Zhu Wang ◽  
Ze Xu Zhou
Keyword(s):  
Mathematical Modeling ◽  
Transmission Line ◽  
Simulation Analysis ◽  
Poor Performance ◽  
Complex Mechanism ◽  
Improve Design ◽  
Line Complex ◽  
Simulation Results ◽  
Low Sensitivity ◽  
And Control

As the long transmission line, complex mechanism, poor performance of regulation and control and low sensitivity of mechanical let-off, so it can not meets the requirements of stable tension. Therefore, the let-off mechanical was improved. This paper takes let-off system of SAURER400 rapier loom as experimental subject, mathematical modeling to every parts of loom, and takes simulation and comparison. The simulation results show the improvement of mechanical can meet the basic requirements of weaving, and it indicates the works that done former are effective and correct.

scholarly journals Unique Kinetic Properties of Phenol-Degrading Variovorax Strains Responsible for Efficient Trichloroethylene Degradation in a Chemostat Enrichment Culture

2005 ◽  
Vol 71 (2) ◽  
pp. 904-911 ◽  
Author(s):  
Hiroyuki Futamata ◽  
Yayoi Nagano ◽  
Kazuya Watanabe ◽  
Akira Hiraishi
Keyword(s):  
16S Rrna ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Competitive Inhibition ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Kinetic Properties ◽  
Rrna Gene ◽  
High Affinity ◽  
Degrading Bacteria ◽  
Tce Degradation

ABSTRACT A chemostat enrichment of soil bacteria growing on phenol as the sole carbon source has been shown to exhibit quite high trichloroethylene (TCE)-degrading activities (H. Futamata, S. Harayama, and K. Watanabe, Appl. Environ. Microbiol. 67:4671-4677, 2001). To identify the bacterial populations responsible for the high TCE-degrading activity, a multidisciplinary survey of the chemostat enrichment was conducted by employing molecular-ecological and culture-dependent approaches. Three chemostat enrichment cultures were newly developed under different phenol-loading conditions (0.25, 0.75, and 1.25 g liter−1 day−1) in this study, and the TCE-degrading activities of the enrichments were measured. Among them, the enrichment at 0.75 g liter−1 day−1 (enrichment 0.75) expressed the highest activity. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments detected a Variovorax ribotype as the strongest band in enrichment 0.75; however, it was not a major ribotype in the other samples. Bacteria were isolated from enrichment 0.75 by direct plating, and their 16S rRNA genes and genes encoding the largest subunit of phenol hydroxylase (LmPHs) were analyzed. Among the bacteria isolated, several strains were affiliated with the genus Variovorax and were shown to have high-affinity-type LmPHs. The LmPH of the Variovorax strains was also detected as the major genotype in enrichment 0.75. Kinetic analyses of phenol and TCE degradation revealed, however, that these strains exhibited quite low affinity for phenol compared to other phenol-degrading bacteria, while they showed quite high specific TCE-degrading activities and relatively high affinity for TCE. Owing to these unique kinetic traits, the Variovorax strains can obviate competitive inhibition of TCE degradation by the primary substrate of the catabolic enzyme (i.e., phenol), contributing to the high TCE-degrading activity of the chemostat enrichments. On the basis of physiological information, mechanisms accounting for the way the Variovorax population overgrew the chemostat enrichment are discussed.

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