Number of found documents: 253
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Image analysis of particle size: effect of light source type
Formánek R.; Kysela B.; Šulc R.
2019 - English
Agitation of two immiscible liquids or solid-liquid suspension is a frequent operation in chemical and metallurgical industries. The sizes of particles, bubbles or droplets can be determined by the Image Analysis Technique. It is known that the quality of captured images depends significantly on the original image background that is mainly affected by the type of the light source. The aim of this contribution is to investigate the effect of light source type on image quality. The four types of light sources were tested: 1) 1000 W halogen lamp, 2) 72 W LED bar panel, 3) 60 W LED chip, and 4) 90 W LED chip. The illumination intensity and image background quality were investigated for each tested light sources. The effect of the shutter speed on evaluated particle sizes was tested using monodisperse spherical calibration particles having diameter of 1.19 mm. The difference observed between particle sizes evaluated by image analysis for given light source and declared calibration particle diameter was used as a measure of light source quality. Keywords: image analysis; light source Available in digital repository of ČVUT.
Image analysis of particle size: effect of light source type

Agitation of two immiscible liquids or solid-liquid suspension is a frequent operation in chemical and metallurgical industries. The sizes of particles, bubbles or droplets can be determined by the ...

Formánek R.; Kysela B.; Šulc R.
České vysoké učení technické v Praze, 2019

Measurement of drop size distribution time rate for liquid-liquid dispersion using IPI method
Jašíková D.; Kotek M.; Kysela B.; Šulc R.; Kopecký V.
2019 - English
The liquid-liquid dispersion properties are studied mainly by image analysis (IA) and Interferometric Particle Imaging (IPI). Drop sizes will be investigated in dilute dispersion since in this case the break up phenomena is the dominating and is not affected by phase fraction. Characteristics of the size distribution and the evolution of two liquid-liquid phase’s disintegration were studied. The IPI method was used for subsequent detailed study of the disintegrated droplets. We compared two liquids: Rhodosil Oil 47V50, and Silicone Oil AP1000 under stirrer rate of 540 rpm, and 760 rpm. The experiment run in the scaled model of agitated tank with Rushton turbine. Keywords: mixing; IPI method; drop size distribution Available in digital repository of ČVUT.
Measurement of drop size distribution time rate for liquid-liquid dispersion using IPI method

The liquid-liquid dispersion properties are studied mainly by image analysis (IA) and Interferometric Particle Imaging (IPI). Drop sizes will be investigated in dilute dispersion since in this case ...

Jašíková D.; Kotek M.; Kysela B.; Šulc R.; Kopecký V.
České vysoké učení technické v Praze, 2019

Probabilistic Analysis of Precast Concrete Element
Šrámek M.; Novák J.
2019 - English
Precast concrete pavement technology belongs to construction methods which provide rapid construction and minimal on site work in comparison with cast-in-place concrete pavement technology. Mainly, it is used for repairs and rehabilitation of existing pavements. Nowadays, it is being developed an innovative precast concrete pavement system whose advantages consist in rapid and easy construction and use of recycled material. The presented paper focuses on the probabilistic analysis of a selected precast concrete element developed for a surface course of the system. The analysis was conducted on a computational model of the selected element by using a stochastic method and nonlinear finite element method in order to observe the effect of uncertainties and variations in material properties, load and geometrical imperfection on the element behavior. Namely, it concerns geometrical imperfections, young's modulus of elasticity and reinforcement position. The probabilistic analyzes were evaluated with respect to element deflection, tensile stress in reinforcement, compressive stress in concrete and crack width. The obtained findings will serve for the optimization of the precast concrete element before the pavement test section is going to be constructed. Keywords: Precast pavement; imperfection; probabilistic analysis Available in digital repository of ČVUT.
Probabilistic Analysis of Precast Concrete Element

Precast concrete pavement technology belongs to construction methods which provide rapid construction and minimal on site work in comparison with cast-in-place concrete pavement technology. Mainly, it ...

Šrámek M.; Novák J.
České vysoké učení technické v Praze, 2019

Utilization of recycled plastic in concrete production
Horáková A.; Novák J.
2019 - English
The environmental aspects of sustainable development in the construction industry consist in the utilization of secondary raw materials in design and construction of new structures. Recycling of waste plastics reduces environmental impacts such as global warming and climate change, raw material and energy consumption, waste production and total environmental pollution. The fact that China significantly reduced the import of plastic waste in 2017 raises the question of dealing with this waste in other states. A complicated recycling process of waste plastics puts pressure on scientific community to find new, more efficient ways of using this waste in the construction industry. Waste plastics recycling for use in concrete building applications takes place predominantly in two forms: replacing natural aggregate with plastic aggregate and using fibre for fibre-reinforced concrete. The paper deals with the behavior and mechanical properties of a completely innovative material called polymerbeton, which is composed of aggregate and plastic waste, which replaces cement as a binder. The completely unique composition of this concrete required testing of production technologies and standard quasi-static experimental tests to obtain basic knowledge about the behavior and mechanical properties of this composite. The obtained knowledge show that special attention must be paid to the production of material, which takes place at elevated temperatures. This composite has a relatively high tensile strength compared to conventional concrete and brittle fracture behavior. In the next phases of the research project the optimization of the production technologies and the composition of the composite will be provided. Keywords: Polymer concrete; Sustainable development; Recyclation; Strenght tests; PET Available in digital repository of ČVUT.
Utilization of recycled plastic in concrete production

The environmental aspects of sustainable development in the construction industry consist in the utilization of secondary raw materials in design and construction of new structures. Recycling of waste ...

Horáková A.; Novák J.
České vysoké učení technické v Praze, 2019

Optimized use of the steam accumulator in the combined heat and power production
Votava J.; Kyncl J.; Müller Z.; Vetoshkin L.; Rimbala J.
2019 - English
This paper presents technical analysis of the usage of steam accumulator in the combined heat and power production and also in all general steam production. Created mathematical model is possible to use for evening on wanted slope of steam flow change. Keywords: Cogeneration; Ancillary Services (AnS); System Services (SyS); Green bonus Available in digital repository of ČVUT.
Optimized use of the steam accumulator in the combined heat and power production

This paper presents technical analysis of the usage of steam accumulator in the combined heat and power production and also in all general steam production. Created mathematical model is possible to ...

Votava J.; Kyncl J.; Müller Z.; Vetoshkin L.; Rimbala J.
České vysoké učení technické v Praze, 2019

Practical CRIS Interoperability
Dvořák J.; Chudlarský T.; Špaček J.
2019 - English
Institutional Current Research Information Systems typically interoperate and interact with a rich variety of other information systems and services. We aim at providing a basic list and discussing the motivations, the technical aspects of the information interchange that is taking place, and potential benefits of applying CERIF. Our findings are illustrated on the example of the CRIS of the Czech Technical University in Prague, an in-house built CRIS with over two decades of history. Keywords: Institutional Current Research Information Systems; information system interoperability; information interchange standardization; CERIF Available in digital repository of ČVUT.
Practical CRIS Interoperability

Institutional Current Research Information Systems typically interoperate and interact with a rich variety of other information systems and services. We aim at providing a basic list and discussing ...

Dvořák J.; Chudlarský T.; Špaček J.
České vysoké učení technické v Praze, 2019

Discrete analysis on non-cubic lattices
Nesterenko M.; Pošta S.
2019 - English
The paper proposes practical and computation methods for discrete analysis of functions defined on the weight lattices or model sets of semisimple Lie groups. They are entirely group theoretical, being based on finite groups and their duals. Numerical computations approximate target functions uniformly on the entire infinite space. Several examples are considered. Keywords: discrete analysis; weight lattice; quasicrystal; Lie group; Lie algebra; Fourier transform Available in digital repository of ČVUT.
Discrete analysis on non-cubic lattices

The paper proposes practical and computation methods for discrete analysis of functions defined on the weight lattices or model sets of semisimple Lie groups. They are entirely group theoretical, ...

Nesterenko M.; Pošta S.
České vysoké učení technické v Praze, 2019

Interaction Experiment At The Bukov URF
Svoboda J.; Vašíček R.; Smutek J.; Hausmannová L.; Franěk J.; Rukavičková L.; Večerník P.
2019 - English
The Interaction Experiment is being prepared by the CTU, ÚJV and ČGS for SÚRAO at the Bukov URF.The experiment is concerned with the study of mutual interactions between the candidate materials for the engineered barriers of the DGR, the rock environment and groundwater.The objective is to investigate the various interactions between the materials planned for use in the future DGR in a real rock environment.Thus,the experiment is located in the Bukov URF at a depth of 550m of the former Rožná I mine. The experiment consists of ten physical models emplaced in horizontal boreholes.Five of the models have been designed for the study of interactions at ambient temperatures and the other five for the study of interactions at elevated temperatures (4x up to 100°C, 1x up to 200°C).Heated models are cylindrical in shape with a diameter of 240mm and a length of 1450mm.Rod heaters have been placed along the axes of each of the models.The heaters are surrounded by a bentonite filling and geotextile or concrete rings have been placed along the interface between the bentonite layer and the rock so as to provide for the homogeneous influx of water. Other models have a diameter of 90mm and do not contain heaters.All the models are being artificially saturated with local groundwater. In order to investigate the various types of interactions,differing combinations of materials were selected for each model:compacted bentonite with two differing dry densities,a bentonite pellet mixture,standard concrete and low pH concrete.All the materials as well as the rock environment were characterized in detail.It is assumed that the loading phase for each of the physical models will last for at least 3 years.Following the completion of the experiments, the individual physical models will be dismantled and analysed in detail.The outcome of the experiment will consist of a detailed description of the geochemical and mineralogical changes to the various materials. Keywords: URF; in-situ experiment; bentonite; interactions Available in digital repository of ČVUT.
Interaction Experiment At The Bukov URF

The Interaction Experiment is being prepared by the CTU, ÚJV and ČGS for SÚRAO at the Bukov URF.The experiment is concerned with the study of mutual interactions between the candidate materials for ...

Svoboda J.; Vašíček R.; Smutek J.; Hausmannová L.; Franěk J.; Rukavičková L.; Večerník P.
České vysoké učení technické v Praze, 2019

Electromagnetic disturbance in industrial LED lighting systems
Bálský M.; Zeifart T.; Kozlok M.
2019 - English
The electromagnetic disturbance of individual LED luminaires and the requirements of technical standards to limit it are well known. This paper focuses on the analysis of electromagnetic disturbance of entire industrial LED lighting systems with a high number of luminaires and hence high power consumption. In such large industrial lighting systems, the effects of electromagnetic disturbance may be very different from the electromagnetic disturbance of individual luminaires. Keywords: LED light; lighting system; industry; total harmonic distortion Available in digital repository of ČVUT.
Electromagnetic disturbance in industrial LED lighting systems

The electromagnetic disturbance of individual LED luminaires and the requirements of technical standards to limit it are well known. This paper focuses on the analysis of electromagnetic disturbance ...

Bálský M.; Zeifart T.; Kozlok M.
České vysoké učení technické v Praze, 2019

Improvement of transient stability using STATCOM combined with optimization
Vetoshkin L.; Votava J.; Kyncl J.; Müller Z.
2019 - English
Further improvement of FACTS (Flexible Alternating Current Transmission System) control can help to increase the transient stability of a power system without adding extra grid inertia. Sophisticated optimization algorithms and modern Computer Algebra Systems provide new means of controller synthesis for power systems. The paper presents an approach of enhancement of transient stability using FACTS devices, particularly STATCOM (Static Synchronous Compensators), combined with optimization. Furthermore, chapter 3 describes different ways of defining the objective function. Different approaches are compared using the case study model that was implemented in MATLAB/Simulink. Keywords: FACTS; STATCOM; optimization; transient stability Available in digital repository of ČVUT.
Improvement of transient stability using STATCOM combined with optimization

Further improvement of FACTS (Flexible Alternating Current Transmission System) control can help to increase the transient stability of a power system without adding extra grid inertia. Sophisticated ...

Vetoshkin L.; Votava J.; Kyncl J.; Müller Z.
České vysoké učení technické v Praze, 2019

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