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1
Content available remote Process Engineering in Iron Production
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EN
Balance, thermodynamic and mainly kinetic approaches using methods of process engineering enable to determine conditions under which iron technology can actually work in limiting technological states, at the lowest reachable fuel consumption (reducing factor) and the highest reachable productivity accordingly. Kinetic simulation can be also used for variant prognostic calculations. The paper deals with thermodynamics and kinetics of iron making process. It presents a kinetic model of iron oxide reduction in a low temperature area. In the experimental part it deals with testing of iron ore feedstock properties. The theoretical and practical limits determined by heat conditions, feedstock reducibility and kinetics of processes are calculated.
EN
The purpose of the present investigation was to prepare pH-sensitive hydrogels from photo-crosslinked poly(ethylene glycol) diacrylate (PEG-DA). Rutile titanium dioxide (TiO2) was employed to modify the PEG-DA hydrogels. The rutile titanium dioxide (TiO2) nanoparticles were prepared by direct oxidation of titanium in the presence of polyethylene glycol (PEG) at high temperature. The nanoparticles were characterized by FT-IR, XRD and SEM. The influence of experimental conditions, such as pH, type and amount of photoinitiators on the release profiles of donepezil hydrochloride (active pharmaceutical ingredient for Alzheimer disease) from modified PEG-DA hydrogels, was investigated. The drug release processes were analyzed kinetically using zero-order, first-order, Hixson-Crowell and Peppas models.
EN
This paper studies kinetic aspects of toner flotation in a mechanical cell with methyl isobutyl carbinol (MIBC) as a frother by using a synthetic toner sample 212+0 μm in a size at variable pH. The effect of the MIBC dosage and pH value on the flotation behavior of the toner has been investigated in terms of toner recovery and fiber recovery. Two kinetic models, the classical first order model and a modified first order model, have been tested and compared. It was established that the achieved optimal parameters of flotation were MIBC 1.5 mg/dm3 and pH from 7 to 12. The obtained results indicate that the toner floats rapidly and that flotation kinetics fits well the modified first order model with a very good correlation coefficient compared to the correlation coefficient for the classical first order model.
EN
This study evaluated the kinetics of water vapour adsorption on the surface of starch molecules derived from wheat. The aim of the study was to determine an equation that would allow estimation of water content in tested material in any time-point of the adsorption process aimed at settling a balance with the environment. An adsorption isotherm of water vapour on starch granules was drawn. The parameters of the Guggenheim, Anderson, and De Boer equation were determined by characterizing the tested product and adsorption process. The equation of kinetics of water vapour adsorption on the surface of starch was determined based on the Guggenheim, Anderson, and De Boer model describing the state of equilibrium and on the model of a first-order linear inert element describing the changes in water content over time.
EN
In this study, the relationships between the liberation degree and the kinetic breakage parameters of a chromite ore obtained from the Burdur (Türkiye) were examined under the laboratory conditions. Firstly, liberation degrees for chromite particles were determined by the particle counting method in a metal microscope for 4 different size groups. Secondly, the breakage parameter of chromite ore which was dry ground with a ball mill was obtained using standard test methods. Additionally, the model parameters were also determined for the fractional interstitial fillings (U) of the chromite sample. Thirdly, the kinetic grinding parameters were compared with the liberation degree of the chromite sample. As a result of the tests, a very good correlation was obtained with R2=0.998, and regression analysis in the grinding processing of the chromite ore was used to verify the validity of the relationship parameter of Si that was produced. To these, it was found that interstitial fillings (U=0.6, 0.8, 1.0, and 1.2) have an effect on the grinding.
EN
Spent Pot Lining (SPL) cathode pot, waste from the aluminium smelting process needs detoxification from cyanides, washing out water-soluble salts and extraction of the cryolite (Na3AlF6) decomposition products to be recycled. Revealed cryolite decomposition mechanism with NaOH opens possibilities to explore its critical role in the reactive extraction process. Common Na+ ion from NaOH hinders the solubility of the product but also drives mass transfer to the reaction site. Reaction mass balance provides adequate liquid to solid ratio (L/S) and NaOH concentration range. A newly developed kinetic model based on Whitman film theory and NaOH mass flow enables prediction of the reaction time to decompose cryolite to a low enough level. Results show that the internal particle resistance to transport (1/ks) is 19 times larger than the external (1/kl) one and governs the whole process.
EN
Kinetic resolution of (R)- and (S)-mandelic acid by its transesterification with vinyl acetate catalysed by Burholderia cepacia lipase has been studied. The influence of the initial substrate concentration on the kinetics of process has been investigated. A modified ping-pong bi-bi model of enzymatic transesterification of (S)-mandelic acid including substrate inhibition has been developed. The values of kinetic parameters of the model have been estimated. We have shown that the inhibition effect revealed over a certain threshold limit value of the initial concentration of substrate.
EN
The paper presents results of methane fermentation of municipal solid waste organic fraction (OFMSW) under mesophilic conditions. The carbon balance of the process was developed on the basis of CHNS elementary analysis, VFA and biogas contents. A simple kinetic model for OFMSW fermentation was proposed. The model comprising the first- order-kinetics equation (with or without VFA inhibition) and the Monod equation was verified experimentally.
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The article presents the results of kinetic studies of the wet oxidation process of dairy sewage. The dairy sewage, obtained straight from the production line, was subjected to oxidation at pH close to the natural value of 7. Experiments were carried out in a stirred batch tank reactor at the oxygen partial pressure equal to 1 MPa and at temperature ranging from 473 to 593 K. The effectiveness of organic compounds decomposition was estimated based on the measurement of TOC. The kinetics of decomposition of milk components, ie lactose, protein and fat, as well as the kinetics of oxidation of intermediate products was the aim of the study. Measurement of the concentration of protein, fat and lactose was done with a milk composition analyzer, calibrated in relation to the dairy sewage. The obtained results were used to develop a mathematical model of wet oxidation of dairy sewage, including the group of analyzed compounds.
PL
Artykuł prezentuje wyniki badań kinetycznych procesu mokrego utleniania ścieków pochodzących z przemysłu mleczarskiego. Utlenianiu poddane zostały ścieki mleczarskie o ich naturalnym pH zbliżonym do wartości 7, pobrane bezpośrednio po procesie produkcyjnym. Badania prowadzone były w okresowym reaktorze zbiornikowym z mieszadłem, przy ciśnieniu cząstkowym tlenu wynoszącym 1 MPa, w zakresie zmienności temperatury od 473 do 593 K. Oceny efektywności stopnia rozkładu związków organicznych dokonano na podstawie pomiaru wartości TOC. Celem badań było zbadanie kinetyki rozkładu związków wchodzących w skład mleka - laktozy, białek i tłuszczu oraz kinetyki przemian produktów pośrednich utleniania - lotnych kwasów tłuszczowych. Pomiar stężenia białek, tłuszczu i laktozy odbywał się z wykorzystaniem analizatora składu mleka, skalibrowanego w stosunku do ścieków mleczarskich. Otrzymane wyniki posłużyły do budowy modelu matematycznego procesu mokrego utleniania ścieków, obejmującego grupy analizowanych związków.
12
Content available remote Wet Oxidation of Dairy Sewage
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EN
Results of kinetic studies on the process of wet oxidation of dairy sewage are presented. Experiments were carried out in a stirred batch tank reactor at the oxygen partial pressure equal to 1 MPa and at temperature ranging from 473 to 523 K. Dairy sewage was subjected to oxidation at a natural pH close to 4. The efficiency of decomposition of organic compounds was estimated on the basis of TOC measurement. The highest TOC reduction rate reached 79.6%. A kinetic model of the process was proposed and its parameters were determined experimentally. Good agreement of the experimental and calculated results was obtained.
PL
W pracy przedstawiono wyniki badań kinetycznych procesu mokrego utleniania ścieków przemysłu mleczarskiego. Badania przeprowadzono w okresowym reaktorze zbiornikowym z mieszadłem, przy ciśnieniu cząstkowym tlenu O2 P = 1 MPa, w zakresie temperatury od 473 do 523 K. Utlenianiu poddawano ścieki mleczarskie o ich naturalnym odczynie zbliżonym do wartości 4. Oceny efektywności rozkładu związków organicznych dokonano na podstawie pomiaru wartości TOC. Najwyższy stopień redukcji TOC ukształtował się na poziomie 79,6%. Zaproponowano model kinetyczny procesu i na podstawie badań eksperymentalnych określono jego parametry. Uzyskano dobrą zgodność wyników doświadczalnych i obliczeniowych.
13
Content available remote Kinetyczne przesłanki mechanizmu kondensacji Knoevenagela
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PL
Badano kinetykę reakcji kondensacji Knoevenagela aldehydu salicylowego z malonianem dietylu, katalizowaną 4-piperydynopiperydyną w toluenie jako rozpuszczalniku. Zaproponowano model kinetyzacji reakcji.
EN
The kinetic of the Knoevenagel condensation of salicylaldehyde with diethylmalonate in the presence of 4-piperidinopiperidyne as a catalyst in toluene as a solvent has been studied. The reaction mechanism was proposed and kinetic model was numerically verified.
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Content available remote Wet Oxidation of Dairy Sewage
75%
EN
Results of kinetic studies on the process of wet oxidation of dairy sewage are presented. Experiments were carried out in a stirred batch tank reactor at the oxygen partial pressure equal to 1 MPa and at temperature ranging from 473 to 523 K. Dairy sewage was subjected to oxidation at a natural pH close to 4. The efficiency of decomposition of organic compounds was estimated on the basis of TOC measurement. The highest TOC reduction rate reached 79.6%. A kinetic model of the process was proposed and its parameters were determined experimentally. Good agreement of the experimental and calculated results was obtained.
PL
W pracy przedstawiono wyniki badań kinetycznych procesu mokrego utleniania ścieków przemysłu mleczarskiego. Badania przeprowadzono w okresowym reaktorze zbiornikowym z mieszadłem, przy ciśnieniu cząstkowym tlenu PO2 = 1 MPa, w zakresie temperatury od 473 do 523 K. Utlenianiu poddawano ścieki mleczarskie o ich naturalnym odczynie zbliżonym do wartości 4. Oceny efektywności rozkładu związków organicznych dokonano na podstawie pomiaru wartości TOC. Najwyższy stopień redukcji TOC ukształtował się na poziomie 79,6%. Zaproponowano model kinetyczny procesu i na podstawie badań eksperymentalnych określono jego parametry. Uzyskano dobrą zgodność wyników doświadczalnych i obliczeniowych.
EN
With the ultimate aim of improving mixer geometry by using a mathematical model for rubber mixing, this Paper concentrates on the dispersive mixing process of filler disagglomeration. Specially designed elongational flow experiments were used to achieve dispersive mixing under conditions of known stress and strain rate history. It was found that the disagglomeration process is satisfactorily described by a first order differential equation with the rate constant proportional to the power density experienced by the compound during mixing. The kinetic model was implemented in original finite element software to obtain a 2-dimensional simulation of mixing in a twin rotor internal mixer. It was concluded that the 2-dimensional simulation would be useful for relating cross-sectional rotor geometry to efficiency of filler disagglomeration, and hence dispersive mixing.
PL
Opracowano model kinetyczny niskociśnieniowej syntezy metanolu z gazu syntezowego na polskim katalizatorze przemysłowym Cu/ZnO/MnO[3]/Al[2]O[3] (BT-1). Wyprowadzenie równań kinetycznych oparto na szczegółowym mechanizmie reakcji, uwzględniającym tworzenie metanolu z CO i niezależnie z CO[2]. W układzie przebiega również reakcja konwersji tlenku węgla z wodą. Do oszacowania parametrów modelu wykorzystano dane doświadczalne uzyskane w reaktorze pracującym w układzie gaz-zawiesina katalizatora. Symulacja procesu z użyciem opracowanego modelu wykazała, że metanol powstaje głównie z CO[2].
EN
A mathematical model was developed to describe kinetics of the low-pressure methanol synthesis from syngas over Polish commercial Cu/ZnO/MnO[3]/Al[2]O[3] (BT-1) catalyst. A rigorous reaction network including methanol formation from CO and CO[2] and the water gas-shift reaction was a basis for the derivation of the rate expressions. The kinetic parameters were estimated by nonlinear regression of the experimental data obtained in a stirred tank slurry reactor. Model simulation showed that under reaction conditions, methanol is formed mainly from CO[2].
PL
Podjęto próbę sformułowania modelu strukturalnego opisującego stechiometrię i kinetykę wytwarzania kwasu cytrynowego przez Aspergillus niger. Dane doświadczalne procesu wgłębnej biosyntezy kwasu cytrynowego prowadzonego w podłożu syntetycznym z sacharozą w 30 degree C wykorzystano do identyfikacji modelu. Stwierdzono, że zaproponowany model matematyczny bardzo dobrze odzwierciedla charakter zmian danych doświadczalnych.
EN
A structured, non-segregated model that describes the stoichiometry and kinetics of citric acid production by Aspergillus niger from hexoses has been developed. The model was validated in experiments of the submerged culture of A. niger in synthetic sugar media at 30 stopni C. The formulated stoichiometry and balance equations allowed model predictions to be in qualitative and quantitative agreement with the experimental data.
EN
This research focused on using coriander seeds as low cost adsorbent to remove heavy metals ions such as lead, zinc, and nickel from wastewater. Different parameters were studied to obtain the best results, such as pH, contact time, adsorbent dosage, concentration of initial metals and agitation speed. The highest results were obtained at pH 6, 105 min contact time, 1 g/100 ml dosage, 50 mg/l initial concentration of metal ions and 200 rpm agitation speed at temperature 25 ± 2 °C, which were 95.926%, 89.799% and 79.255% for lead, zinc and nickel ions, respectively. The results were also categorized as the Langmuir and Freundlich models, and found that the Freundlich isotherm fit the experimental data better than the Langmuir isotherm. The pseudo-second order was shown to have a high degree of fitness based on kinetic data. The adsorbent was characterized using a variety of techniques, including Fourier transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM).
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The article presents the results of kinetic studies of the wet oxidation process of dairy sewage. The dairy sewage, obtained straight from the production line, was subjected to oxidation at pH close to the natural value of 7. Experiments were carried out in a stirred batch tank reactor at the oxygen partial pressure equal to 1 MPa and at temperature ranging from 473 to 593 K. The effectiveness of organic compounds decomposition was estimated based on the measurement of TOC. The kinetics of decomposition of milk components, ie lactose, protein and fat, as well as the kinetics of oxidation of intermediate products was the aim of the study. Measurement of the concentration of protein, fat and lactose was done with a milk composition analyzer, calibrated in relation to the dairy sewage. The obtained results were used to develop a mathematical model of wet oxidation of dairy sewage, including the group of analyzed compounds.
PL
Artykuł prezentuje wyniki badań kinetycznych procesu mokrego utleniania ścieków pochodzących z przemysłu mleczarskiego. Utlenianiu poddane zostały ścieki mleczarskie o ich naturalnym pH zbliżonym do wartości 7, pobrane bezpośrednio po procesie produkcyjnym. Badania prowadzone były w okresowym reaktorze zbiornikowym z mieszadłem, przy ciśnieniu cząstkowym tlenu wynoszącym 1 MPa, w zakresie zmienności temperatury od 473 do 593 K. Oceny efektywności stopnia rozkładu związków organicznych dokonano na podstawie pomiaru wartości TOC. Celem badań było zbadanie kinetyki rozkładu związków wchodzących w skład mleka - laktozy, białek i tłuszczu oraz kinetyki przemian produktów pośrednich utleniania - lotnych kwasów tłuszczowych. Pomiar stężenia białek, tłuszczu i laktozy odbywał się z wykorzystaniem analizatora składu mleka, skalibrowanego w stosunku do ścieków mleczarskich. Otrzymane wyniki posłużyły do budowy modelu matematycznego procesu mokrego utleniania ścieków, obejmującego grupy analizowanych związków.
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