No (257)
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257
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Velocity measurements on continuous micro water jet using fluorescent PMMA seeding particles
Zeleňák, Michal; Ščučka, Jiří; Souček, Kamil
2017 - English
The paper deals with application of optical diagnostic techniques for velocity\nmeasurements of continuous micro water jet. The combination of Particle image\nvelocimetry, Particle tracking velocimetry, Laser induced fluorescence and\nShadowgraphy methods have been applied together with the use of fluorescent\nPMMA seeding particles. An experimental closed water circuit was designed with\na low-pressure water pump, and a series of experiments was conducted to\nmeasure the velocity of seeding particles in the water jet flow below the diamond\nmicro-nozzle outlet. The basic principles of the methods used in experiments are\nalso described.
Keywords:
micro water jet; fluorescent PMMA particles; velocity; LIF; PTV; PIV
Available on request at various institutes of the ASCR
Velocity measurements on continuous micro water jet using fluorescent PMMA seeding particles
The paper deals with application of optical diagnostic techniques for velocity\nmeasurements of continuous micro water jet. The combination of Particle image\nvelocimetry, Particle tracking ...
Community area risk assessment for flash flood
Kolejka, Jaromír; Rapant, P.; Krejčí, Tomáš
2017 - English
The flash floods forecasting is struggling mainly with extraordinary irregularities in origin of causal precipitations. They only in conjunction with the territory water saturation caused by antecedent precipitations start effect of other local factors that can consequences of short-term extreme precipitation either worsen or mitigate vice versa. Other community area features represent a permanent potential for an adequate territory response after heavy rains. According to current knowledge, it is possible to assess the flash floods hazard of a particular territory in case of extreme precipitation in advance. If such precipitations are already on the ground, or if they are just coming up in the atmosphere, the local flood control headquarters has at least time enough to call alarm and issue a flood warning. In the ideal case, it is possible to incorporate such area assessment into the concept of decision-making of the disaster staff and to insert it into the master plan documentation. The aim of this text is to present above mentioned original method, which can be used in authomatic GIS environment by public administration as well as other users. Suggested procedure is based on automatic hydrologic modelling in ArcGIS platform in combination with advanced digital terrain model. Delimitation of partial catchment basins is also part of our proces, which enables to decide about the risk value of the area in more detail using weighted arithmetic mean. These methods result to detailed imagination about probably threatened localities - and it is essential tool for local authorities and their decision making process in case of early warning.
Keywords:
flash flood; local development; risk assessment; planning documentation
Available at various institutes of the ASCR
Community area risk assessment for flash flood
The flash floods forecasting is struggling mainly with extraordinary irregularities in origin of causal precipitations. They only in conjunction with the territory water saturation caused by ...
Perception of wind power plants construction on the local level: Case studies in East Bohemia
Janová, M.; Kunc, J.; Frantál, Bohumil
2017 - English
The paper aims to evaluate selected findings of a research regarding the attitudes of the inhabitants of East Bohemian municipalities (Anenska Studanka and Vitezna) towards the construction of wind power plants and the perception thereof. A survey was carried out among the inhabitants of the two municipalities, as well as nearby municipalities and guided interviews were conducted with their mayors. The two selected sites differ in population numbers, time of power plant construction, number and size of the turbines and form of financial settlement. In the case of Vitezna, the power plant in question was community-funded, meaning that a portion of the shares was offered to the inhabitants (a unique case in the Czech Republic). The results indicated that, over time, the attitudes and opinions of the respondents from all the municipalities concerned have shifted towards a more positive perception of wind power plants. They have, however, also become more polarized. Citizens' movements against further construction have been created, even though it is currently not possible in the Czech Republic, especially given that the government has cancelled funding for the support of clean power. Respondents who were found to have the fewest issues with the wind power plants were younger than 30 years, graduates of secondary education and resided at a greater distance from the stations without having direct visual contact with them from their home.
Keywords:
wind power plants; perception; local level; Eastern Bohemia
Available at various institutes of the ASCR
Perception of wind power plants construction on the local level: Case studies in East Bohemia
The paper aims to evaluate selected findings of a research regarding the attitudes of the inhabitants of East Bohemian municipalities (Anenska Studanka and Vitezna) towards the construction of wind ...
The Flow of Mixture Vapors in the Vacuum Column K101, Nominal and Reduced Capacity
Říha, Zdeněk
2017 - English
The report contains CFD results and description of the gas mixture flow in the bottom part of the vacuum column K101. There were solved two cases. Both cases had the same geometry. The difference between ones was in quantity of vapors on the inputs. The first case was calculated for the nominal quantity of vapors. The second case was calculated for reduced quantity (60% of nominal quantity) of vapors. Calculated results of above mentioned cases are placed in report´s enclosures 1 and 2.
Keywords:
CFD results; vacuum column; gas mixture flow
Available at various institutes of the ASCR
The Flow of Mixture Vapors in the Vacuum Column K101, Nominal and Reduced Capacity
The report contains CFD results and description of the gas mixture flow in the bottom part of the vacuum column K101. There were solved two cases. Both cases had the same geometry. The difference ...
Application of high speed water jet technology for concrete repair
Bodnárová, L.; Sitek, Libor; Foldyna, Josef; Jarolím, T.
2017 - English
This article brings selected knowledge from the long-term cooperation between\nthe Brno University of Technology, the Faculty of Civil Engineering, the Institute of\nTechnology of Building Materials and Components, and the Academy of Sciences of\nthe Czech Republic, v.v.i., Institute of Geonics, Ostrava – Poruba in the field of\nthe interaction of high-speed water jets and concrete, especially with regard to\nthe use of high-speed water jet technology for the removal of surface layers of\nconcrete during repair of concrete.
Keywords:
high speed water jet (HSWJ); concrete; concrete repair; X-ray CT; carbon nanotubes (CNTs)
Available on request at various institutes of the ASCR
Application of high speed water jet technology for concrete repair
This article brings selected knowledge from the long-term cooperation between\nthe Brno University of Technology, the Faculty of Civil Engineering, the Institute of\nTechnology of Building Materials ...
Evaluation of selected surface characteristics of CW004A copper disintegrated by PWJ
Lehocká, D.; Klich, Jiří
2017 - English
Paper deals with copper CW004A surface characteristics evaluation after\ndisintegration by enhanced pulsating water jet. The main aim was identify and\ndescribe areas of pulsating water jet disintegration effects on material with using\ncircular nozzle diameter. 25 samples were disintegrated at change traverse speed\nv = 0.1 – 20 mm·s-1, for assessment of individual areas formation. Surface\ncharacteristics were evaluated based on surface roughness parameters Ra [μm],\nRz [μm], Rp [μm], Rv [μm], mass material removal Δm [mg.mm-1] and volume\nmaterial removal Vm [mm3]. Based on experimental investigation, three areas of\npulsating water jet effects on material were determined.
Keywords:
pulsating water jet; copper; roughness; topography
Available on request at various institutes of the ASCR
Evaluation of selected surface characteristics of CW004A copper disintegrated by PWJ
Paper deals with copper CW004A surface characteristics evaluation after\ndisintegration by enhanced pulsating water jet. The main aim was identify and\ndescribe areas of pulsating water jet ...
Flow Field Analysis in Abrasive Head as Tool for High-Speed Abrasive Jet Cutting
Říha, Zdeněk; Zeleňák, Michal
2017 - English
The article presents an analysis of the calculated flow field of water, vapor and\nabrasive particles in the inner geometry of a tool called the abrasive head using\na multiphase numerical flow model. The results of the above-mentioned analysis\nare compared with measured values of abrasive particle velocities at the outlet of\nthe abrasive head. For measuring of abrasive particle velocities, the PIV method\nwas used.
Keywords:
abrasive head; high-speed water jet; abrasive particle velocity
Available on request at various institutes of the ASCR
Flow Field Analysis in Abrasive Head as Tool for High-Speed Abrasive Jet Cutting
The article presents an analysis of the calculated flow field of water, vapor and\nabrasive particles in the inner geometry of a tool called the abrasive head using\na multiphase numerical flow model. ...
Cutting experiments with ASJ at 1500 bar
Zeleňák, Michal; Foldyna, Josef; Souček, Kamil; Klichová, Dagmar
2016 - English
The aim of experimental work was to determine cutting condition maximal, middle and fine traverse speeds for selected materials and thicknesses. Materials were cut at pressure 1500 bars and 10% of suspension concentration. Secondary objective is long-term monitoring of nozzles wear using X – Ray CT tomography.
Keywords:
high-speed abrasive suspension jet; cutting; technology
Available at various institutes of the ASCR
Cutting experiments with ASJ at 1500 bar
The aim of experimental work was to determine cutting condition maximal, middle and fine traverse speeds for selected materials and thicknesses. Materials were cut at pressure 1500 bars and 10% of ...
Two phase flow of water and air, flat jet above the plate, jet sloping 75° and 90°
Říha, Zdeněk
2016 - English
The report contains CFD results and description of the two phase flow water and air. Water comes into the computational domain through\nsimplified nozzle which creates water flat jet with spraying angle c. 40o. The flat jet falls on the wall surface where flows along the surface plate in all directions (x,y mainly). The aim of the work is to show how the falling water flows on the wall surface with help of advanced CFD model. Two cases had been solved there with various jets sloping to the surface plate. The first case contains results with configuration of the geometry for the jet sloping 75o and second case contains results with configuration of the geometry for the jet sloping 90o, see enclosures 1 and 2. Given calculation had been done as steady state calculations.
Keywords:
CFD model; two phase flow water and air; jet sloping
Available on request at various institutes of the ASCR
Two phase flow of water and air, flat jet above the plate, jet sloping 75° and 90°
The report contains CFD results and description of the two phase flow water and air. Water comes into the computational domain through\nsimplified nozzle which creates water flat jet with spraying ...
Assessment of the Aggregate in Historical Plasters
Rezek, P.; Martinec, Petr
2016 - English
This article deals with the analysis of the aggregates of historical plasters. In the paper there is described the assessment methodology of the aggregates of historical plasters. The assessment of the aggregates is carried out with the example of a set of original and modern-day aggregates taken in the prelature and convent of the Želiv Monastery. Composition of fine aggregates of historical plasters was compared to the composition of the aggregates from resources of nearby watercourses. As well as it was assessed the geological character of nearby vicinity of the Monastery. For the analysis of character of the plaster fine aggregates it is applied the optical microscopy of the plaster thin sections, grain size analysis, mineralogical and petrographic analysis of the aggregates. The presented results document the differences in the origin of the aggregate used in plasters.
Keywords:
aggregate; composition; geological situation; historical plaster; petrography
Available at various institutes of the ASCR
Assessment of the Aggregate in Historical Plasters
This article deals with the analysis of the aggregates of historical plasters. In the paper there is described the assessment methodology of the aggregates of historical plasters. The assessment of ...
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