Search results for "batch"
showing 10 items of 113 documents
New time-dependent Monte Carlo algorithm designed to model three-phase batch reactor processes: applications on 2,4-dinitro-toluene hydrogenation on …
2003
Abstract The hydrogenation of 2,4-dinitro-toluene on a Pd/C catalyst was employed as a test reaction to simulate, by the time-dependent Monte Carlo method, processes occurring in a three-phase batch reactor working at isobar and isotherm conditions. A new time-dependent Monte Carlo algorithm, including an original subroutine useful to reduce the time of the simulations, was developed and implemented in Fortran language. The paper describes the flowchart of the code together with the main technical details and the involved physical and chemical models. Computational characteristics, such as the simulated time to reach surface steady state conditions and the effects of the catalyst morphology…
A Friendly-Biological Reactor SIMulator (BioReSIM) for studying biological processes in wastewater treatment processes
2014
Biological processes for wastewater treatments are inherently dynamic systems because of the large variations in the influent wastewater flow rate, concentration composition and the adaptive behavior of the involved microorganisms. Moreover, the sludge retention time (SRT) is a critical factor to understand the bioreactor performances when changes in the influent or in the operation conditions take place. Since SRT are usually in the range of 10-30 days, the performance of biological reactors needs a long time to be monitored in a regular laboratory demonstration, limiting the knowledge that can be obtained in the experimental lab practice. In order to overcome this lack, mathematical model…
Stochastic Scheduling of Production Orders Under Uncertainty
2017
This paper attempts to solve the problem of searching minimum production order completion time variants by means of stochastic logical structures with all cost curve descent points and corresponding minimum-cost schedules. The analysis presented in this paper considers scheduling of unique and small batch production, predominantly to order, which accounts for changing requirements of the customer, the complexity and long production process makespan including its technical preparation. Scheduling of production order was performed by means of GAN networks and employed the concept of soft relations. The cost/time relation analysis is based on two-node network models using the cost curve. A new…
Sequential batch membrane bio-reactor for wastewater treatment: The effect of increased salinity
2016
In this work, a sequential batch membrane bioreactor pilot plant is investigated to analyze the effect of a gradual increase in salinity on carbon and nutrient removal, membrane fouling and biomass kinetic parameters. The salinity was increased by 2 g NaCl L-1 per week up to 10 g NaCl L-1. The total COD removal efficiency was quite high (93%) throughout the experiment. A gradual biomass acclimation to the salinity level was observed during the experiment, highlighting the good recovery capabilities of the system. Nitrification was also influenced by the increase in salinity, with a slight decrease in nitrification efficiency (the lowest value was obtained at 10 g NaCl L-1 due to lower nitri…
Impact of Gluten-Friendly Bread on the Metabolism and Function of In Vitro Gut Microbiota in Healthy Human and Coeliac Subjects
2016
The main aim of this paper was to assess the in vitro response of healthy and coeliac human faecal microbiota to gluten-friendly bread (GFB). Thus, GFB and control bread (CB) were fermented with faecal microbiota in pH-controlled batch cultures. The effects on the major groups of microbiota were monitored over 48 h incubations by fluorescence in situ hybridisation. Short-chain fatty acids (SCFAs) were measured by high-performance liquid chromatography (HPLC). Furthermore, the death kinetics of Lactobacillus acidophilus, Bifidobacterium animalis subsp. lactis, Staphylococcus aureus, and Salmonella Typhimurium in a saline solution supplemented with GFB or CB were also assessed. The experiment…
Kinetics and characteristics of 70 °C, VFA-grown, UASB granular sludge
1999
We studied in batch reactors the kinetics and characterization of 70 °C, volatile fatty acids (VFAs)-grown, upflow anaerobic sludge blanket granular sludge with 55 and 35 °C sludge as reference. The half-saturation constant (Ks), the inhibition constant (Ki), the maximum specific methane production rate (μCH4max), and the inhibition response coefficient (n) of the 70 °C sludge were 6.15 mM, 48.2 mM, 0.132 h−1, and 2.48, respectively, while no inhibition occurred at 55 and 35 °C, where the Ks was 3.67 and 3.82 mM, respectively. At 70 °C, the highest initial specific methanogenic activity (ISMA, 0.311 gCH4-COD per gram volatile solids per day) on VFAs was about 12–15% lower than that on aceta…
Comparison of different predictive models for nutrient estimation in a sequencing batch reactor for wastewater treatment
2006
Abstract In this paper different predictive models for nutrient estimation in a sequencing batch reactor (SBR) for wastewater treatment are compared: principal component regression (PCR), partial least squares (PLS), and artificial neural networks (ANNs). Two unfolding procedures were used: batch-wise and variable-wise. For the latter unfolding method, X and Y matrix augmentation with lagged variables were used in some models to incorporate process dynamics. The results have shown that batch-wise unfolding PLS models outperform the other approaches. The ANN models are good predictive models, but in this particular case-study, they do not outperform those multivariate projection models that …
Multivariate SPC of a sequencing batch reactor for wastewater treatment
2007
Data from a sequencing batch reactor (SBR) operated for enhanced biological phosphorus removal from wastewater have been analysed in order to propose an efficient MSPC scheme of the process. Different multivariate bilinear approaches have been applied and compared in terms of their capabilities for on-line and off-line fault detection and diagnosis. The typical three-way data structure from a batch process was unfolded batch-wise and variable-wise. In the latter case, two models were built: with (AT) and without (WKFH) removing the main non-linear behaviour of the process data. Since the process consists of several stages, the monitoring strategies tested include: one model for all stages a…
On optimizing firewall performance in dynamic networks by invoking a novel swapping window-based paradigm
2018
Designing and implementing efficient firewall strategies in the age of the Internet of Things (IoT) is far from trivial. This is because, as time proceeds, an increasing number of devices will be connected, accessed and controlled on the Internet. Additionally, an everincreasingly amount of sensitive information will be stored on various networks. A good and efficient firewall strategy will attempt to secure this information, and to also manage the large amount of inevitable network traffic that these devices create. The goal of this paper is to propose a framework for designing optimized firewalls for the IoT. This paper deals with two fundamental challenges/problems encountered in such firewalls…
Sustainable Method Using Filtering Techniques for a Fermentation Process State Estimation
2020
Winemaking is concerned about sustainable energy availability that implies new methods for process monitoring and control. The aim of this paper is to realize a comparative analysis of the possibilities offered using estimation techniques, balances, and filtering techniques such as the Kalman filter (KF) and the extended Kalman filter (EKF), to obtain indirect information about the alcoholic fermentation process during winemaking. Thus, an estimation solution of the process variables in the exponential growing phase is proposed, using an extended observer. In addition, two estimation solutions of this process with the EKF and an estimation of the decay phase of the fermentation process are …