Search results for " kinetic"
showing 10 items of 416 documents
Effect of Pulsed Electric Field Pretreatment on Drying Kinetics, Color, and Texture of Parsnip and Carrot.
2018
The aim of the study was to evaluate the effect of pulsed electric field (PEF) pretreatment on drying kinetics and on color and textural changes in sliced parsnip and carrot. Cell disintegration index measured in parsnips after PEF pretreatment significantly differed from the ones measured for carrots and, consequently, the reduction of the time needed to dry both samples to a final moisture content up to 5% (wet basis). The drying time of the PEF pretreated parsnip was reduced by up to 28% at 70 °C and by up to 21% at 60 °C in carrot, in comparison to untreated samples. The PEF pretreatment influenced the effective diffusivity of water into the samples going from 50 °C to 70 °C: in carrots…
A new plant wide modelling approach for the reduction of greenhouse Gas emission from wastewater treatment plants
2017
Recent studies about greenhouse gas (GHG) emissions show that sewer collection systems and wastewater treatment plants (WWTPs) are anthropogenic GHG potential sources. Therefore, they contribute to the climate change and air pollution. This increasing interest towards climate change has led to the development of new tools for WWTP design and management. This paper presents the first results of a research project aiming at setting-up an innovative mathematical model platform for the design and management of WWTPs. More specifically, the study presents the project’s strategy aimed at setting-up a plant-wide mathematical model which can be used as a tool for reducing/controlling GHG from WWTP.…
Polymer dynamics in thin p-type conducting films investigated by ac-electrogravimetry. Kinetics aspects on anion exclusion, free solvent transfer, an…
2015
A new transfer model is proposed to explain ac-electrogravimetry response of p-doped films. This model takes into account the exclusion effect occurring as a result of the anion transfer. The insertion/expulsion of anions inside a film involves simultaneously the expulsion/insertion of free solvent molecules. The number of solvent molecules excluded depends on the volume of anion transferred. Solvent transfer stimulated by the conformational changes of films constitutes the remaining electrogravimetric response when the exclusion process cannot explain by itself this response. Consequently, the kinetics of this free solvent transfer can be directly related to the kinetics of conformational …
Flow chemistry: Imidazole-based ionic liquid syntheses in micro-scale
2010
The quarternization of an N-atom in the 1-methyl-imidazole with different alkylating agents was investigated to form so-called Ionic Liquids. (3-Chloropropyl)-trimethoxysilane, 1-chlorobutane, diethyl sulfate and methyl trifluoromethanesulfonate were used as alkylating agents. Reaction kinetics range from very slow to instantaneous and the reaction heat from endothermal to extremely exothermal respectively. The reactions were performed under flow conditions using different types of microstructured reactors as well as pre-structurized reactants in the micro-scale. Unusual heat management with integrated heat pipes allow safer performing of highly exothermal reactions with comparably high thr…
Transesterification of rapeseed oil over acid resins promoted by supercritical carbon dioxide
2011
The methanolysis of rapeseed oil catalyzed by commercial styrene-divinylbenzene macroporous acid resins was performed in a batch reactor at 100-140 °C and 10-46 MPa to study the effect of supercritical carbon dioxide (scCO2) on the performances of the process. Reaction temperatures of 120-140 °C were necessary to obtain high enough yields of fatty acid methyl esters. Upon addition of scCO2 faster transesterification kinetics was obtained also at the lowest investigated operating pressure (10-11 MPa), working in two fluid phase systems. Experiments performed changing the reaction time indicated that most of the esters were formed during the first 3 h. When the pressure was increased at 38-46…
Removal of Brilliant Green Dye from Water Using Ficus benghalensis Tree Leaves as an Efficient Biosorbent
2023
The presence of dyes in water stream is a major environmental problem that affects aquatic and human life negatively. Therefore, it is essential to remove dye from wastewater before its discharge into the water bodies. In this study, Banyan (Ficus benghalensis, F. benghalensis) tree leaves, a low-cost biosorbent, were used to remove brilliant green (BG), a cationic dye, from an aqueous solution. Batch model experiments were carried out by varying operational parameters, such as initial concentration of dye solution, contact time, adsorbent dose, and pH of the solution, to obtain optimum conditions for removing BG dye. Under optimum conditions, maximum percent removal of 97.3% and adsorption…
CO rebinding kinetics and molecular dynamics simulations highlight dynamic regulation of internal cavities in human cytoglobin
2013
Abstract: Cytoglobin (Cygb) was recently discovered in the human genome and localized in different tissues. It was suggested to play tissue-specific protective roles, spanning from scavenging of reactive oxygen species in neurons to supplying oxygen to enzymes in fibroblasts. To shed light on the functioning of such versatile machinery, we have studied the processes supporting transport of gaseous heme ligands in Cygb. Carbon monoxide rebinding shows a complex kinetic pattern with several distinct reaction intermediates, reflecting rebinding from temporary docking sites, second order recombination, and formation (and dissociation) of a bis-histidyl heme hexacoordinated reaction intermediate…
Improvement of ALT decay kinetics by all-oral HCV treatment: Role of NS5A inhibitors and differences with IFN-based regimens
2017
Background Intracellular HCV-RNA reduction is a proposed mechanism of action of direct-acting antivirals (DAAs), alternative to hepatocytes elimination by pegylated-interferon plus ribavirin (PR). We modeled ALT and HCV-RNA kinetics in cirrhotic patients treated with currently-used all-DAA combinations to evaluate their mode of action and cytotoxicity compared with telaprevir (TVR)+PR. Study design Mathematical modeling of ALT and HCV-RNA kinetics was performed in 111 HCV-1 cirrhotic patients, 81 treated with all-DAA regimens and 30 with TVR+PR. Kinetic-models and Cox-analysis were used to assess determinants of ALT-decay and normalization. Results HCV-RNA kinetics was biphasic, reflecting …
Efficient Removal of Methyl Red Dye by Using Bark of Hopbush
2022
Methyl red (MR) dye, one of the azo dyes, is mutagenic and its persistence has negative effects on the environment and people’s health. The current work is the first to demonstrate that methyl red dye can be removed effectively and sustainably, utilizing biomass derived from the bark of the Dodonaea viscosa (Hopbush) plant. The Hopbush bark shows effective adsorption of MR, upto 73%, under optimized conditions in an aqueous medium. The experimental conditions were optimized by examining the effect of time, initial dye concentration, pH and ionic strength on the adsorption process in an aqueous medium. Maximum (i.e., 73%) adsorption of MR removal (500 ppm) was observed in highly acidic…
Chemical and biochemical responses to sub−lethal doses of mercury and cadmium in gilthead seabream (Sparus aurata)
2022
Specimens of Sparus aurata were exposed to sub-lethal concentrations of Hg and Cd for 25 days and the levels of both metals were investigated in organs and tissues. Bioaccumulation of Hg decreased as follow: gills > kidney > liver > skin > muscle, while the order of Cd bioaccumulation was: liver > kidney > gills > skin > muscle. Immediately after exposure, both metals showed the highest bioaccumulation in gills and skin indicating that these organs are reliable targets for biomonitoring studies after short term exposure. Metals introduction caused a significant time-dependent concentrations increase in kidney and liver, while in the muscle a significant in-crease of …