Dynamic Optimization of Autocatalytic Esterification in Semi Batch Reactor using Orthogonal Collocation and Control Vector Parameterization Method

Catalyzed Esterification of Propionic Anhydride with 2-Butanol is commonly applied in semi batch reactors where the process variables undergo significant changes during the duration of the batch. In this semi batch operation, there is no steady state and thus no constant setpoints around which the key variables can be regulated

Simulation And Optimization Studies Of Catalyzed Esterification Of Propionic Anhydride With 2-Butanol: Batch Versus Semi Batch Operation.

A model to represent the catalyzed esterification of propionic anhydride with 2-butanol has been developed and simulated

PID Controller for Batch Process using MATLAB-Simulink-Real-Time-Windows Target

The difficulties in implementing a controller in the real process leads to the practice of a real-time user-friendly simulator programming. This paper presents the application of the Simulink model as a Graphical User Interface (GUI) for signal visualization and parameter tuning in the real-time implementations

Online Dynamic Optimization of Feed Flowrate and Temperature Trajectories in Semi Batch Esterification Reactor

In semi batch esterification process, an operating feed flowrate and temperature reactor has a significant effect on conversion that determines final product quality

Apatite formation on calcined kaolin-white Portland cement geopolymer

In this study, calcined kaolin–white Portland cement geopolymerwas investigated for use as biomaterial. Sodiumhydroxide and sodium silicate were used as activators. In vitro test was performed with simulated body fluid (SBF) for bioactivity characterization. The formation of hydroxyapatite bio-layer on the 28-day soaked samples surface was tested using SEM, EDS and XRD analyses. The results showed that the morphology of hydroxyapatite was affected by the source material composition, alkali concentration and curing temperature. The calcined kaolin–white Portland cement geopolymer with relatively high compressive strength could be fabricated for use as biomaterial. The mix with 50% white Portland cement and 50% calcined kaolin had 28-day compressive strength of 59.0 MPa and the hydroxyapatite bio-layer on the 28-day soaked sample surface was clearly evident.This work was financially supported by the Thailand Research Fund (TRF) and Khon Kaen University under the TRF-Royal Golden Jubilee Ph.D. program (Grant No. PHD/0143/2554) and TRF-Senior Research Scholar (Grant No. RTA5780004)

Bioactivity enhancement of calcined kaolin geopolymer with CaCl2 treatment

This paper reports that surface treatment with CaCl2 enhances the bioactivity of a calcined kaolin geopolymer. Calcined kaolin, NaOH solution, sodium silicate solution, and heat curing were used to form geopolymer pastes. A soaked-treatment method was applied to the geopolymer samples using CaCl2 solution as the ion exchange agent. The bioactivity of the material was determined by the simulated body fluid (SBF) in vitro testing method. Scanning electron microscope images showed a dense apatite formation on the treated geopolymer surface after SBF immersion for only 3 days. The CaCl2 treatment promoted compressive strength and enhanced bioactivity by accelerating apatite precipitation and slowing down the rise in pH.This work was financially supported by the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission, through the Advanced Functional Materials Cluster of Khon Kaen University; and Khon Kaen University and the Thailand Research Fund (TRF) under the TRF-Royal Golden Jubilee Ph. D. program (Grant no. PHD/0143/2554); Post-doctoral training program (Grant no. 58110), Graduate school, Khon Kaen University and TRF Senior Research Scholar Contract No. RTA5780004.info:eu-repo/semantics/publishedVersio

SIMULATION AND OPTIMIZATION STUDIES OF CATALYZED ESTERIFICATION OF PROPIONIC ANHYDRIDE WITH 2-BUTANOL: BATCH VERSUS SEMI BATCH OPERATION

ABSTRACT A model to represent the catalyzed esterification of propionic anhydride with 2-butanol has been developed and simulated. Two modes of operation i.e. batch and semi batch have been simulated and compared. The performance of both modes of operation has been compared using two performance indicators i.e. amount of conversion and process time. The effect of feed rate (semi batch) and temperature (both batch and semi batch) towards time required to achieve 97% of conversion has been carried out. Then the time required to achieve 97% conversion in semi batch operation has been optimized using Control Vector Parameterization (CVP) technique. It was observed that the highest conversion can be achieved at the lowest dynamic feed rate. For the effect of temperature, it was found that the process time of batch operation was shorter than in the semi batch if temperature is lower than 323 K, but at temperature greater than 333K, process time required by semi batch is shorter than the batch. For the optimization problem, the optimum temperature and feed rate trajectories obtained were led to shorter process time than batch operation i.e. 98 min for achieving 97% of conversion

The Gut Microbiota and Their Metabolites in Human Arterial Stiffness

Aim: Gut microbiota-derived metabolites, such as short-chain fatty acids (SCFAs) have vasodilator properties in animal and human ex vivo arteries. However, the role of the gut microbiota and SCFAs in arterial stiffness in humans is still unclear. Here we aimed to determine associations between the gut microbiome, SCFA and their G-protein coupled sensing receptors (GPCRs) in relation to human arterial stiffness. / Methods: Ambulatory arterial stiffness index (AASI) was determined from ambulatory blood pressure (BP) monitoring in 69 participants from regional and metropolitan regions in Australia (55.1% women; mean, 59.8± SD, 7.26 years of age). The gut microbiome was determined by 16S rRNA sequencing, SCFA levels by gas chromatography, and GPCR expression in circulating immune cells by real-time PCR. / Results: There was no association between metrics of bacterial α and β diversity and AASI or AASI quartiles in men and women. We identified two main bacteria taxa that were associated with AASI quartiles: Lactobacillus spp. was only present in the lowest quartile, while Clostridium spp. was present in all quartiles but the lowest. AASI was positively associated with higher levels of plasma, but not faecal, butyrate. Finally, we identified that the expression of GPR43 (FFAR2) and GPR41 (FFAR3) in circulating immune cells were negatively associated with AASI. / Conclusions: Our results suggest that arterial stiffness is associated with lower levels of the metabolite-sensing receptors GPR41/GPR43 in humans, blunting its response to BP-lowering metabolites such as butyrate. The role of Lactobacillus spp. and Clostridium spp., as well as butyrate-sensing receptors GPR41/GPR43, in human arterial stiffness needs to be determined

Developmental neurotoxic effects of chronic endosulfan exposure in the zebrafish larvae

Endosulfan was listed as a member of Persistent Organic Pollutants (POP) and the usage was banned, yet this pesticide is still widely used in many developing countries. The usage of this pesticide can reach aquatic system through runoff from agricultural areas. Due to their persistent characteristic in the environment, human population are posed to continuous exposure to endosulfan. Consequently, endosulfan was found in the cord blood and breast milk of pregnant women, thus may induced adverse effects to the developing nervous system. In this study, we focused to determine the developmental neurotoxicity effects of chronic embryonic exposure to endosulfan in the zebrafish larvae. The zebrafish embryos were exposed to several concentrations of endosulfan in a semi static condition, where half of the medium was renewed for every 24 h from 5 hours post fertilization (hpf) until hatching. We measured spontaneous tail coiling at 24 hpf; heart rate at 48 hpf and mortality rate at 72 hpf. We found that, endosulfan decreased the spontaneous tail coiling, heart rate and increased the total percentage of mortality as the concentration increased. At 6 days post fertilization (dpf), we measured the swimming activity of individual larva and found that endosulfan significantly decreased the swimming activity behaviour at 40nM-200nM. The zebrafish larvae exposed to endosulfan higher than 200nM were unable to survive until 6 dpf. We further evaluated anxiety behaviour in the group of 5 larvae at 6 dpf exposed to 200nM endosulfan, with and without visual stimuli. Caffeine (100mg/L) was used as an anxiogenic drug. Caffeine increased the anxiety behaviour while endosulfan decreased the anxiety behaviour in the zebrafish larvae. Our result showed that zebrafish embryos can be an alternative research model to study the developmental neurotoxicity testing at high-throughput screenings