scholarly journals Theoretical formulations and simulations of one-dimensional inhibition kinetics of ethanologenic microorganisms in batch fermenters

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Peter P. Bamaalabong ◽  
Nana Y. Asiedu ◽  
F. Abunde Neba ◽  
Francesca Baidoo ◽  
Ahmad Addo

Abstract The utilization of bio-based technology for energy has piqued researchers' curiosity around the world. As a result, bioethanol fermentation has been a hot topic of research for many scientists since it uses less energy and chemicals, produces fewer harmful by-products and emissions, and has environmentally favorable applications. The modeling and simulations of one-dimensional product and substrate inhibitions for sorghum, maize, and cassava extracts are discussed in this paper. Because it provides an edge over other methodologies, mechanistic modeling techniques are used. Models of substrate and product inhibitions in one dimension (1-D) are constructed. These 1-D models are then confirmed using parameter estimates before being employed in the work's simulations. For each dynamic model constructed, model fitness coefficients (α) are calculated. For the product, the exponential inhibition model, sorghum extract data has the best model fitness coefficient (α = 0.4088), for product sudden stop inhibition model and cassava extract data gives the best model fitness coefficient ($$\alpha $$ α = 0.4417) for product exponential model. The projected yield increases for substrate exponential inhibition with sorghum extract data, substrate linear inhibition with maize extract data, and substrate linear inhibition with cassava extract data are 74%, 27%, and 25%, respectively. This unique framework has offered the industry a wide choice of kinetics models to choose from to alleviate inhibitions in fermentation systems and maximize yield and productivity in the bioethanol fermentation process. Article Highlights The modeling of inhibitions namely linear, sudden stop, and exponential in batch fermentation processes are presented in this article. Model fitness coefficient analysis showed the product as a primary inhibitor and substrate as a secondary inhibitor during the process The cassava and maize processes described linear inhibition model and sorghum fermentation showed exponential product inhibition model.

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yaroslava E. Poroshyna ◽  
Aleksander I. Lopato ◽  
Pavel S. Utkin

Abstract The paper contributes to the clarification of the mechanism of one-dimensional pulsating detonation wave propagation for the transition regime with two-scale pulsations. For this purpose, a novel numerical algorithm has been developed for the numerical investigation of the gaseous pulsating detonation wave using the two-stage model of kinetics of chemical reactions in the shock-attached frame. The influence of grid resolution, approximation order and the type of rear boundary conditions on the solution has been studied for four main regimes of detonation wave propagation for this model. Comparison of dynamics of pulsations with results of other authors has been carried out.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joanna Pietraszewicz ◽  
Aleksandra Seweryn ◽  
Emilia Witkowska

AbstractWe study phase domain coarsening in the long time limit after a quench of magnetic field in a quasi one-dimensional spin-1 antiferromagnetic condensate. We observe that the growth of correlation length obeys scaling laws predicted by the two different models of phase ordering kinetics, namely the binary mixture and vector field. We derive regimes of clear realization for both of them. We demonstrate appearance of atypical scaling laws, which emerge in intermediate regions.


2013 ◽  
Vol 05 (01) ◽  
pp. 1350001 ◽  
Author(s):  
WILLIAM TOH ◽  
ZISHUN LIU ◽  
TENG YONG NG ◽  
WEI HONG

This work examines the dynamics of nonlinear large deformation of polymeric gels, and the kinetics of gel deformation is carried out through the coupling of existing hyperelastic theory for gels with kinetic laws for diffusion of small molecules. As finite element (FE) models for the transient swelling process is not available in commercial FE software, we develop a customized FE model/methodology which can be used to simulate the transient swelling process of hydrogels. The method is based on the similarity between diffusion and heat transfer laws by determining the equivalent thermal properties for gel kinetics. Several numerical examples are investigated to explore the capabilities of the present FE model, namely: a cube to study free swelling; one-dimensional constrained swelling; a rectangular block fixed to a rigid substrate to study swelling under external constraints; and a thin annulus fixed at the inner core to study buckling phenomena. The simulation results for the constrained block and one-dimensional constrained swelling are compared with available experimental data, and these comparisons show a good degree of similarity. In addition to this work providing a valuable tool to researchers for the study of gel kinetic deformation in the various applications of soft matter, we also hope to inspire works to adopt this simplified approach, in particular to kinetic studies of diffusion-driven mechanisms.


2021 ◽  
pp. 2105228
Author(s):  
Ping Wei ◽  
Yong Cheng ◽  
Xiaolin Yan ◽  
Weibin Ye ◽  
Xiangna Lan ◽  
...  

2007 ◽  
Vol 215 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Edgar Erdfelder ◽  
Lutz Cüpper ◽  
Tina-Sarah Auer ◽  
Monika Undorf

Abstract. A memory measurement model is presented that accounts for judgments of remembering, knowing, and guessing in old-new recognition tasks by assuming four disjoint latent memory states: recollection, familiarity, uncertainty, and rejection. This four-states model can be applied to both Tulving's (1985) remember-know procedure (RK version) and Gardiner and coworker's ( Gardiner, Java, & Richardson-Klavehn, 1996 ; Gardiner, Richardson-Klavehn, & Ramponi, 1997 ) remember-know-guess procedure (RKG version). It is shown that the RK version of the model fits remember-know data approximately as well as the one-dimensional signal detection model does. In contrast, the RKG version of the four-states model outperforms the corresponding detection model even if unequal variances for old and new items are allowed for.We show empirically that the two versions of the four-statesmodelmeasure the same state probabilities. However, the RKG version, requiring remember-know-guess judgments, provides parameter estimates with smaller standard errors and is therefore recommended for routine use.


2016 ◽  
Vol 23 (2) ◽  
pp. 448-459 ◽  
Author(s):  
Richard T. Melstrom

This article presents an exponential model of tourist expenditures estimated by a quasi-maximum likelihood (QML) technique. The advantage of this approach is that, unlike conventional OLS and Tobit estimators, it produces consistent parameter estimates under conditions of a corner solution at zero and heteroscedasticity. An application to sportfishing evaluates the role of socioeconomic demographics and species preferences on trip spending. The bias from an inappropriate estimator is illustrated by comparing the results from QML and OLS estimation, which shows that OLS significantly overstates the impact of trip duration on trip expenditures compared with the QML estimator. Both sets of estimates imply that trout and bass anglers spend significantly more on their fishing trips compared with other anglers.


2012 ◽  
Vol 78 (15) ◽  
pp. 5305-5312 ◽  
Author(s):  
Jacob Bælum ◽  
Emmanuel Prestat ◽  
Maude M. David ◽  
Bjarne W. Strobel ◽  
Carsten S. Jacobsen

ABSTRACTMineralization potentials, rates, and kinetics of the three phenoxy acid (PA) herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), and 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP), were investigated and compared in 15 soils collected from five continents. The mineralization patterns were fitted by zero/linear or exponential growth forms of the three-half-order models and by logarithmic (log), first-order, or zero-order kinetic models. Prior and subsequent to the mineralization event,tfdAgenes were quantified using real-time PCR to estimate the genetic potential for degrading PA in the soils. In 25 of the 45 mineralization scenarios, ∼60% mineralization was observed within 118 days. Elevated concentrations oftfdAin the range 1 × 105to 5 × 107gene copies g−1of soil were observed in soils where mineralization could be described by using growth-linked kinetic models. A clear trend was observed that the mineralization rates of the three PAs occurred in the order 2,4-D > MCPA > MCPP, and a correlation was observed between rapid mineralization and soils exposed to PA previously. Finally, for 2,4-D mineralization, all seven mineralization patterns which were best fitted by the exponential model yielded a highertfdAgene potential after mineralization had occurred than the three mineralization patterns best fitted by the Lin model.


1982 ◽  
Vol 243 (1) ◽  
pp. R7-R17 ◽  
Author(s):  
C. Cobelli ◽  
R. Nosadini ◽  
G. Toffolo ◽  
A. McCulloch ◽  
A. Avogaro ◽  
...  

The kinetics of ketone bodies was studied in normal humans by giving a combined bolus intravenous injection of labeled acetoacetate ([14C]AcAc) and D(--)-beta-hydroxybutyrate (beta-[14C]-OHB) to seven subjects after an overnight fast, on two different occasions, and by collecting frequent blood samples for 100 min. Kinetic data were analyzed with both noncompartmental and compartmental modeling techniques. A four-compartment model, representing AcAc and beta-OHB in blood and two equilibrating ketone body compartments, inside the liver and extrahepatic tissues, was chosen as the most reliable mathematical representation; it is physiologically plausible and was able to accurately fit the data. The model permitted evaluation of the in vivo rate of ketone body production in the liver, the individual plasma clearance rates of AcAc and beta-OHB, their initial volumes of distribution, and the transfer rate parameters among the four ketone body compartments. Moreover, the model provided estimates of the components of the rates of appearance of AcAc and beta-OHB in plasma due to newly synthesized ketone body from acetyl-CoA in the liver, and to interconversion and recycling in the liver and extrahepatic tissues. The model also was used to evaluate other methodologies currently employed in the analysis of ketone body turnover data: the conventional approach based on use of the combined specific activity of AcAc and beta-OHB required assumptions not satisfied in vivo, leading to substantial errors in key parameter estimates.


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