Search results for "Kinetic"
showing 10 items of 3064 documents
Convergent results from experimental and theoretical DFT studies of the intramolecular rearrangement of Z-hydrazones of 3-acetyl-1,2,4-oxadiazoles
2004
A combined kinetic and theoretical study of the monocyclic rearrangements of heterocycles (MRH) has been carried out. The interconversion of the Z-hydrazone of 3-benzoyl-5-phenyl-1,2,4-oxadiazole into the corresponding triazole has been experimentally investigated in dioxane/water in the pS(+) range 5.5(5)-13.9. The uncatalyzed region has been examined at the DFT level using a model system formed by the Z-hydrazone of 3-formyl-1,2,4-oxadiazole and one or two water molecules. The environmental effect of the solvent has been emulated using a continuum model (COSMO) approach. The kinetic data suggest a concerted process where the magnitude of the activation barrier is determined by the interpl…
Freeze-out radii extracted from three-pion cumulants in pp, p–Pb and Pb–Pb collisions at the LHC
2014
In high-energy collisions, the spatio-temporal size of the particle production region can be measured using the Bose-Einstein correlations of identical bosons at low relative momentum. The source radii are typically extracted using two-pion correlations, and characterize the system at the last stage of interaction, called kinetic freeze-out. In low-multiplicity collisions, unlike in high-multiplicity collisions, two-pion correlations are substantially altered by background correlations, e.g. mini-jets. Such correlations can be suppressed using three-pion cumulant correlations. We present the first measurements of the size of the system at freeze-out extracted from three-pion cumulant correl…
Otrējo spirtu dinamiskā kinētiskā sadalīšana
2019
Antrinių alkoholių dinaminė kinetinė rezoliucija. Simonas Balkaitis. Darbo vadovas: Dr. chem. Artis Kinēns. Magistrinį darbą sudaro 63 puslapiai, 10 iliustracijų, 31 schema, 14 lentelių, 1 lygtis, 53 literatūros šaltiniai. Darbas parašytas anglų kalba. Pirmiausia buvo ištirta antrinių alkoholių racemizacija įvairių iridžio, rutenio ir geležies katalizatorių pagalba. Tuomet, racemizacijai tinkamiausiuose tirpiklių variantuose buvo tiriama alkoholių kinetinė rezoliucija. Gauti duomenys buvo panaudoti naujos dinaminės kinetinės rezoliucijos procedūros paieškose.
Determination of sorption properties of heavy metals in various biosorbents
2018
Various techniques of determination of properties of physicochemical processes of heavy metal sorption in biosorbents were analysed. The methods of preparing and storing samples, conditions of experiment performance, as well as the methods of data interpretation were discussed. Two procedures of study were analysed: (1) in the static system of biosorbent-solution contact and (2) in the system of dynamic flow of solution. Copper cation sorption was studied. The effect of consecutive stages of the study on the quality of final results was shown. A high degree of uncertainty of the sorption capacity assessment was reported, which was dependent on the manner of conducting the study. The applica…
Investigation of propoxylation and ethoxylation of 2-ethylhexanol in the presence of an alkaline and DMC type catalyst at initial stages of the synth…
2016
This paper reports results from monopropoxylation and monoethoxylation of ethylhexyl alcohol performed in the presence of KOH and DMC type catalysts, respectively. The existing differences are discussed in terms of kinetic performance of the syntheses, as well as compositions of the obtained products. The investigated DMC type catalyst showed 60 to 70 times higher conversion rates, narrower homologue distributions and higher selectivity, as compared to KOH. Interpretation of the experimental results was performed using kinetic parameters of the Wejbul Nycander Gold model and the Natta Mantica relationships. In spite of any differences between the reactivity of the investigated catalysts and…
Modelling of the air purification from volatile organic compounds in a trickle-bed bioreactor
2016
Badano proces oczyszczania powietrza ze styrenu, substancji zaliczanej do grupy lotnych związków organicznych (LZO), prowadzony w pilotowym bioreaktorze strużkowym (TBB). Ponieważ najważniejszym etapem procesu oczyszczania powietrza z LZO w bioreaktorze strużkowym jest biologiczna reakcja jego rozkładu, zatem, projektując proces, należy przede wszystkim starannie wyselekcjonować mikroorganizmy efektywnie rozkładające usuwane z powietrza zanieczyszczenie, określić warunki najkorzystniejsze dla ich wzrostu oraz wyznaczyć kinetykę reakcji. W wyniku testów porównawczych wyselekcjonowano szczep efektywnie wykorzystujący styren jako jedyne źródło węgla i energii. Był to, pochodzący z kolekcji VTT…
Modelling of the cometabolic decomposition of 4-chlorophenol and phenol by the Stenotrophomonas maltophilia KB2 strain
2017
Zaprezentowano model rozkładu 4-chlorofenolu przez szczep Stenotrophomonas maltophilia KB2 w obecności fenolu jako substratu wzrostowego. Opracowanie tego modelu wymagało wykonania czterech serii badań: biodegradacji różnych dawek czystego fenolu, biodegradacji różnych dawek czystego 4-CP, biodegradacji 4-CP w obecności fenolu przy różnym stosunku stężeń obu substratów oraz biodegradacji 4-CP przez komórkiw fazie spoczynku, indukowane wstępnie fenolem. Szczegółowo omówiono sposoby wyznaczania poszczególnych parametrów równań opisujących szybkość degradacji substratów wzrostowego i niewzrostowego oraz przyrostu biomasy. W oparciu o stworzoną bazę danych obliczono m.in. stałe półnasycenia KSg…
Establishing a threshold for rainfall‐induced landslides by a kinetic energy–duration relationship
2020
Many investigators have attempted to define the threshold of landslide failure, that is, the level of the selected climatic variable above which a rainfall-induced landslide occurs. Intensity–duration (I–d) relationships are the most common type of empirical thresholds proposed in the literature for predicting landslide occurrence induced by rainfall. Recent studies propose the use of the kinetic power per unit volume of rainfall (J m−2 mm−1) to quantify the threshold of landslides induced by rainfall. In this paper, the relationship between rainfall duration and kinetic power corresponding to landslides triggered by rain was used to propose a new approach to define the threshold for predic…
Sorafenib in Mice – A Pharmacokinetic Study
2015
Pharmacokinetic models are applied to determine the drug distribution in the organism with respect to a given administration. Models based on body anatomy and physiology can provide an accurate description of drug concentrations reached in specific organs and tissues of mammals. This article proposes a model based on mammalian anatomy and physiology to predict the biodistribution in mice of sorafenib, an anti-cancer drug, with specific attention to the concentration reached in the liver, as that is the action site in case of hepatocellular carcinoma treatment. The model reveals a close correspondence respect to experimental concentration data in the organism and also assesses with good fide…
Drying kinetics and physico-chemical quality of mango slices
2019
Mango (Mangifera indica L.) is an important tropical fruit consumed worldwide and grown in Italy only in Sicily, where the areas of the Tyrrhenian coast have proved to be suitable to produce valuable fruits. Mango fruit has a pleasant aroma and taste, which are important qualities for consumer’s sensorial acceptance. However, they are highly perishable, prone to progressive undesired changes if stored untreated, resulting in around 25% postharvest losses, which is further increased during storage and transportation. An alternative for reducing the above-mentioned undesired changes is the dehydration of the cut fruit, which reduce the fruit water activity, thereby avoiding the deteriorative …