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Number of found documents:
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Electrochemical Properties of Pretomanid. New drug for Tuberculosis Treatment
Deri, M.; Vespi, M.; Giannarelli, S.; Hromadová, Magdaléna
2024 - English
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.
Keywords:
pretomanid; dimetridazole; cyclic voltammetry; reduction mechanism
Available on request at various institutes of the ASCR
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 ...
Redox Properties of Pyrene-Cyclohexene Conjugates – Electrochemical Study
Koláčná, Lucie; Čubiňák, M.; Tobrman, T.; Ludvík, Jiří
2024 - English
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.
Keywords:
pyrene; cyclohexene; conjugation
Available on request at various institutes of the ASCR
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 ...
Electrochemical Valorization of Lignocellulosic Biomass Amination of Furfural and 5-Hydroxymethylfurfural
Donkeng Dazie, Joel; Koláčná, Lucie; Urban, Jiří; Lamač, Martin; Ludvík, Jiří
2024 - English
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.
Keywords:
furfural; 5-hydroxymethylfurfural; (di)amines
Available on request at various institutes of the ASCR
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 ...
Electrochemical Properties of Newly Synthesized Selaginpulvilins
Dostálová, L.; Sokolová, Romana; Schwarzová-Pecková, K.; Rýček, L.
2024 - English
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.
Keywords:
oxidation; cyclic voltammetry; selaginpulvilins
Available on request at various institutes of the ASCR
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 ...
3D-printed Electrodes with Nearly Ideal Charge Transfer Characteristics
Vaněčková, Eva; Sebechlebská, Táňa; Kolivoška, Viliam
2024 - English
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.
Keywords:
three-dimensional printing; electrochemistry; electrodes
Available on request at various institutes of the ASCR
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 ...
Galloping of insulated bundled overhead line - nonlinear numerical analysis in time domain
Macháček, Michael; Hračov, Stanislav
2024 - English
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.
Keywords:
aerial bundled conductors; wind effects; galloping; limit cycle oscillation
Available in digital repository of the ASCR
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, ...
Applicable Adaptive Discounted Fully Probabilistic Design of Decision Strategy
Molnárová, Soňa
2024 - English
The work addresses the issue of decreased utility of future rewards, referred to as discounting, while utilizing fully probabilistic design (FPD) of decision strategies. FPD obtains the optimal strategy for decision tasks using only probability distributions, which is its main asset. The standard way of solving decision tasks is provided by Markov decision processes (MDP), which FPD covers as a special case. Methods of solving discounted MDPs have already been introduced. However, the use of FPD might be advantageous when solving tasks with an unknown system model. Due to its probabilistic nature, FPD is able to obtain a more precise estimation of this model. After previously introducing discounting and system model estimation to FPD, the current work examines the effect of discounting on decision processes and its possible advantages when dealing with an unknown system model.
Keywords:
Bayesian estimation; decision making; discounting; forgetting; probabilistic strategy design; supression of aproximate modelling impact
Fulltext is available at external website.
Applicable Adaptive Discounted Fully Probabilistic Design of Decision Strategy
The work addresses the issue of decreased utility of future rewards, referred to as discounting, while utilizing fully probabilistic design (FPD) of decision strategies. FPD obtains the optimal ...
Numerical study of the steady airflow in the human respiratory system during inhaling and exhaling
Lancmanová, Anna; Bodnár, Tomáš
2024 - English
This paper presents some of the initial results of the numerical simulations of a steady turbulent flow in human upper airways during inhalation and exhalation. The mathematical model is based on the system of Reynolds-Averaged incompressible Navier-Stokes equations complemented by the SST k − ω turbulence model. The simulations were performed using finite-volume open source solver OpenFOAM on a realistic three-dimensional geometry. The main aim of this particular study is to verify the computational setup with special focus on appropriate choice and implementation of boundary conditions. The prescribed boundary conditions are chosen to mimic the physiological conditions during normal breathing cycle. This study aims to gain an insight into the airflow behavior during the inhalation and exhalation process by comparing the results of two distinct simulations corresponding to two different (opposite) flow rates . The obtained local flow rates and flow fields for both cases are presented and mutually compared. This initial work should serve as a foundation for future more complex simulations that will include the time-dependent and compressible effects.
Keywords:
human airways; incompressible Navier-Stokes; OpenFOAM
Available in digital repository of the ASCR
Numerical study of the steady airflow in the human respiratory system during inhaling and exhaling
This paper presents some of the initial results of the numerical simulations of a steady turbulent flow in human upper airways during inhalation and exhalation. The mathematical model is based on the ...
Assessment of the Presence of Hazardous Components in Textile Waste
Shtukaturova, Anastasia
2024 - English
An up-flow percolation test was chosen to identify and characterize heavy metals and PFAS constituents in textile waste. Up-flow column percolation tests are used on a laboratory scale to assess the leaching behavior of a hazardous substance from a waste in a given state as a function of time. The test was performed according to the European Technical Standard CEN/TS 14405. Preliminary results showed the following heavy metals in the leachates Al, As, Co, Cr, Cu, Fe, Mn, Pb, Zn and Sb, with Al, Cr, Fe, Mn and Zn being predominant.
Keywords:
textile waste; percolation test; PFAS; heavy metals
Available in a digital repository NRGL
Assessment of the Presence of Hazardous Components in Textile Waste
An up-flow percolation test was chosen to identify and characterize heavy metals and PFAS constituents in textile waste. Up-flow column percolation tests are used on a laboratory scale to assess the ...
Drone Based Vertical Profiling of Black Carbon Aerosols at a Rural Background and an Urban Site in Central Europe
Julaha, Kajal
2024 - English
This research aims to assess the vertical distribution of BC aerosols using a drone and micro Aethalometer AE51 at two distinct sites in the Czech Republic: 1. NAOK (National Atmospheric Observatory Košetice) representing a regional background, and 2. MFF (Faculty of Mathematics and Physics in Prague) representing an urban site. At NAOK, a 250-meter measurement tower is accessible, providing a means to validate and calibrate the drone measurements.
Available in a digital repository NRGL
Drone Based Vertical Profiling of Black Carbon Aerosols at a Rural Background and an Urban Site in Central Europe
This research aims to assess the vertical distribution of BC aerosols using a drone and micro Aethalometer AE51 at two distinct sites in the Czech Republic: 1. NAOK (National Atmospheric Observatory ...
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