Počet nalezených dokumentů: 11854
Publikováno od do

Emerging Contaminants in Sewage Sludge: Analysis and Their Removal by Pyrolysis
Hušek, Matěj
2024 - anglický
The study continues with flame retardants (e.g., phosphorus-based or brominated) present in sludge, which may pose a hazard to nature and human health3,4. There is a lack of information on their pyrolysis removal and occurrence in the sludge in the Czech Republic. Klíčová slova: sewage sludge; pyrolysis; PFAS; flame retardants Plné texty jsou dostupné v digitálním repozitáři NUŠL
Emerging Contaminants in Sewage Sludge: Analysis and Their Removal by Pyrolysis

The study continues with flame retardants (e.g., phosphorus-based or brominated) present in sludge, which may pose a hazard to nature and human health3,4. There is a lack of information on their ...

Hušek, Matěj
Ústav chemických procesů, 2024

Cholinium Based Ionic Liquids: Influence of Water as a Co-solvent on Their Physico-chemical Properties and Preliminary Results for Dissolution of Biopolymers
Souvenir Zafindrajaona, Mahasoa-Salina
2024 - anglický
Ionic liquids (ILs) are emerging as promising alternative solvents in the field of natural substance extraction, offering significant advantages over traditional solvents. Since the last decade, we notice the increasing use of greener solvent alternatives such as Natural Deep Eutectic Solvents (NaDES) or ILs for the extraction of highly valuable compounds from natural sources such as lignocellulose. During this presentation, the influence of water on heat capacity, density, speed of sound and TGA will be discussed and the preliminary results for lignin dissolution willbe presented. Plné texty jsou dostupné v digitálním repozitáři NUŠL
Cholinium Based Ionic Liquids: Influence of Water as a Co-solvent on Their Physico-chemical Properties and Preliminary Results for Dissolution of Biopolymers

Ionic liquids (ILs) are emerging as promising alternative solvents in the field of natural substance extraction, offering significant advantages over traditional solvents. Since the last decade, we ...

Souvenir Zafindrajaona, Mahasoa-Salina
Ústav chemických procesů, 2024

Growth and Phosphorus Dynamics During Tolypothrix tenuis Cultivation – a Cyanobacterium of Biotechnological Potential
Mušálková, Petra
2024 - anglický
Here I investigated the course of biomass growth, phosphorus uptake and changes in intracellular phosphorus content in T. tenuis in a batch cultivation. Cultivation experiment was held in multiple bubble columns during a light regime (alternating light and dark periods 16 and 8h). Thanks to this experiment I was able to obtain a growth curve of T. tenuis. The decrease of phosphorus concentration in the medium was disproportionally faster\nthan biomass growth resulting in significant oscillations of phosphorus content in the biomass, which are typical characteristics for LPU. It was also observed, that after all phosphorus was removed from the medium, the algae growth continues over time, while obviously utilizing intracellular phosphorus reserves. These findings are valuable in course of using this cyanobacterium for efficient bioremediation of eutrophic water based on phosphorus removal by targeted algae cultivation. Plné texty jsou dostupné v digitálním repozitáři NUŠL
Growth and Phosphorus Dynamics During Tolypothrix tenuis Cultivation – a Cyanobacterium of Biotechnological Potential

Here I investigated the course of biomass growth, phosphorus uptake and changes in intracellular phosphorus content in T. tenuis in a batch cultivation. Cultivation experiment was held in multiple ...

Mušálková, Petra
Ústav chemických procesů, 2024

Influence of Material Properties and Mixing Dynamics on Heat Transport in Granular Materials
Kokavcová, Anna
2024 - anglický
This study evaluates the effect of rotational speed on heat transfer and analyzes particle motion at different stirrer rotational frequencies to understand how primary and secondary flows affect heat transfer efficiency. It also examines the effect of Young’s modulus on heat transfer at different agitator\noperating speeds. Key simulation parameters and their influence 33 on heat transfer efficiency are detailed to improve the reproducibility and applicability of the results. Klíčová slova: granular mixing; heat transfer; DEM Plné texty jsou dostupné v digitálním repozitáři Akademie Věd.
Influence of Material Properties and Mixing Dynamics on Heat Transport in Granular Materials

This study evaluates the effect of rotational speed on heat transfer and analyzes particle motion at different stirrer rotational frequencies to understand how primary and secondary flows affect heat ...

Kokavcová, Anna
Ústav chemických procesů, 2024

Electrochemical Properties of Pretomanid. New drug for Tuberculosis Treatment
Deri, M.; Vespi, M.; Giannarelli, S.; Hromadová, Magdaléna
2024 - anglický
The electrochemical behavior of Pretomanid (PA 824) has been investigated in acetonitrile by cyclic voltammetry at different scan rates and compared to dimetridazole reduction in order to elucidate its redox mechanism. Both compounds show similar reduction behavior in the aprotic solvent that involves one electron transfer to the nitro group. The reduction of Pretomanid is more difficult and the stability of its nitro anion radical is much lower compared to the dimetridazole molecule. Klíčová slova: pretomanid; dimetridazole; cyclic voltammetry; reduction mechanism Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Electrochemical Properties of Pretomanid. New drug for Tuberculosis Treatment

The electrochemical behavior of Pretomanid (PA 824) has been investigated in acetonitrile by cyclic voltammetry at different scan rates and compared to dimetridazole reduction in order to elucidate ...

Deri, M.; Vespi, M.; Giannarelli, S.; Hromadová, Magdaléna
Ústav fyzikální chemie J. Heyrovského, 2024

Redox Properties of Pyrene-Cyclohexene Conjugates – Electrochemical Study
Koláčná, Lucie; Čubiňák, M.; Tobrman, T.; Ludvík, Jiří
2024 - anglický
The series of 16 compounds for "organic electronics" comprising the double-bond cyclohexene core extended by pyrene and/or other aromatics were electrochemically characterized by rotating disk voltammetry in N,N-dimethylformamide. Due to multiple substitutions, the resulting potential gap represents the sum of all substituent effects. Different combinations of substituents can be used to achieve the desired properties of cyclohexene-pyrene derivatives. The electrochemical data presented in this contribution facilitate further tuning of properties of these molecules and systems to achieve features required in material chemistry just by means of chemical modification. Klíčová slova: pyrene; cyclohexene; conjugation Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Redox Properties of Pyrene-Cyclohexene Conjugates – Electrochemical Study

The series of 16 compounds for "organic electronics" comprising the double-bond cyclohexene core extended by pyrene and/or other aromatics were electrochemically characterized by rotating disk ...

Koláčná, Lucie; Čubiňák, M.; Tobrman, T.; Ludvík, Jiří
Ústav fyzikální chemie J. Heyrovského, 2024

Electrochemical Valorization of Lignocellulosic Biomass Amination of Furfural and 5-Hydroxymethylfurfural
Donkeng Dazie, Joel; Koláčná, Lucie; Urban, Jiří; Lamač, Martin; Ludvík, Jiří
2024 - anglický
Furfural (FF) and 5-hydroxymethylfurfural (HMF) isolated from waste lignocellulosic biomass represent renewable sources. The present contribution deals with the transformation of FF and HMF into furfuryl amines which are important precursors namely for pharmaceutical synthesis. First, FF and HMF underwent condensation reactions with various amines which were electrochemically monitored to optimize the process. The resulting Schiff bases were identified by NMR and subsequently electrochemically reduced in basic media. The vicinal diamine (aminopinacol) was the main product besides the expected furfuryl amines. This reaction is a contribution to green synthesis because it was performed electrochemically, in water, and without any metallic catalysts. Klíčová slova: furfural; 5-hydroxymethylfurfural; (di)amines Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Electrochemical Valorization of Lignocellulosic Biomass Amination of Furfural and 5-Hydroxymethylfurfural

Furfural (FF) and 5-hydroxymethylfurfural (HMF) isolated from waste lignocellulosic biomass represent renewable sources. The present contribution deals with the transformation of FF and HMF into ...

Donkeng Dazie, Joel; Koláčná, Lucie; Urban, Jiří; Lamač, Martin; Ludvík, Jiří
Ústav fyzikální chemie J. Heyrovského, 2024

Electrochemical Properties of Newly Synthesized Selaginpulvilins
Dostálová, L.; Sokolová, Romana; Schwarzová-Pecková, K.; Rýček, L.
2024 - anglický
The electrochemical properties of newly synthesized selaginpulvilin were investigated by cyclic voltammetry and UV-Vis spectroelectrochemistry. The subject of the study were two\nselaginpulvilins differing in the presence of a hydroxyl group in the media of 0.1 mol L-1 tetrabutylammonium hexafluorophosphate as supporting electrolyte in anhydrous acetonitrile. Both\ncompounds provided an oxidative signal in the positive region until +2.0 V. Klíčová slova: oxidation; cyclic voltammetry; selaginpulvilins Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Electrochemical Properties of Newly Synthesized Selaginpulvilins

The electrochemical properties of newly synthesized selaginpulvilin were investigated by cyclic voltammetry and UV-Vis spectroelectrochemistry. The subject of the study were two\nselaginpulvilins ...

Dostálová, L.; Sokolová, Romana; Schwarzová-Pecková, K.; Rýček, L.
Ústav fyzikální chemie J. Heyrovského, 2024

3D-printed Electrodes with Nearly Ideal Charge Transfer Characteristics
Vaněčková, Eva; Sebechlebská, Táňa; Kolivoška, Viliam
2024 - anglický
3D printing is an outstanding manufacturing tool for prototyping customized designs at reduced time and costs, having found applications in fields such as medicine or the automotive industry. The development of printable electrically conductive composite materials brought a revolution to electrochemistry, with 3D-printed electrodes being intensively studied from the viewpoint of\nanalytical performance and stability. However, it is often reported that 3D-printed electrodes have poor charge transfer characteristics, typically due to limited exposure of the electrically conductive phase at the composite surface to the surrounding solution. In this work, we devise and apply simple electrochemical activation procedures that lead to a significant improvement of charge transfer characteristics of 3D printed electrodes. Klíčová slova: three-dimensional printing; electrochemistry; electrodes Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
3D-printed Electrodes with Nearly Ideal Charge Transfer Characteristics

3D printing is an outstanding manufacturing tool for prototyping customized designs at reduced time and costs, having found applications in fields such as medicine or the automotive industry. The ...

Vaněčková, Eva; Sebechlebská, Táňa; Kolivoška, Viliam
Ústav fyzikální chemie J. Heyrovského, 2024

Galloping of insulated bundled overhead line - nonlinear numerical analysis in time domain
Macháček, Michael; Hračov, Stanislav
2024 - anglický
Our contribution focuses on a 3D numerical nonlinear analysis of galloping in a specific bundled overhead line with ice accretion. We studied the susceptibility to this self-excited oscillation, critical onset wind speeds, and global dynamic response of a very low-tensioned line with simulated icing observed on similar real conductors. Due to the highly nonlinear mechanical behavior of such a flexible cable, we employed the Newmark integration method combined with the iterative Newton-Raphson method. We analyzed two numerical models of the overhead line loaded by the wind: one assuming nonlinearity only in the wind load, while retaining the linearity of the mechanical system itself, and the other representing a fully nonlinear system including geometrical nonlinearity. Our analysis revealed that the determined critical wind speeds for the onset of galloping are in relatively close ranges for both models. However, numerical simulations with the fully nonlinear system indicated significantly lower amplitudes of limit cycle oscillations, especially at higher wind speeds, compared to the linear model of the line. This underscores the necessity of using fully nonlinear models during the design stage of such low-tensioned aerial conductors. Klíčová slova: aerial bundled conductors; wind effects; galloping; limit cycle oscillation Plné texty jsou dostupné v digitálním repozitáři Akademie Věd.
Galloping of insulated bundled overhead line - nonlinear numerical analysis in time domain

Our contribution focuses on a 3D numerical nonlinear analysis of galloping in a specific bundled overhead line with ice accretion. We studied the susceptibility to this self-excited oscillation, ...

Macháček, Michael; Hračov, Stanislav
Ústav teoretické a aplikované mechaniky, 2024

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