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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. ...
Zajištění stability hnědouhelných pilířů kotvením
Ďuriš, L.; Šňupárek, Richard
2016 - Czech
Pro zajištění stability důlních chodeb respektive fungování celého systému chodba - pilíř je nutno udržet stabilní zejména uhelné pilíře mezi chodbami. Tato podmínka se dá zvládnout správným dimenzováním zejména šířky pilíře a samostatnou svorníkovou výztuží, která výrazně zvyšuje stabilitu a životnost chodeb. Vzhledem k zatím chybějícím zkušenostem a měřením z podmínek hnědouhelné pánve je potřeba tyto návrhy nejdříve ověřit pokusnými díly, které by bylo vhodné osadit příslušnou měřící technikou. The paper deals with the issue of stability and stabilization of coal pillars by using rockbolt support. Application of the method room pillar can become very beneficial to the place where it can be somehow limited extraction using longwall face. This method is respectful of the overburden and excavated areas stay stable. The problem with this method is currently designing pillars so as to sufficiently handle pass the load.
Keywords:
reinforcement; anchoring; rock massif
Available at various institutes of the ASCR
Zajištění stability hnědouhelných pilířů kotvením
Pro zajištění stability důlních chodeb respektive fungování celého systému chodba - pilíř je nutno udržet stabilní zejména uhelné pilíře mezi chodbami. Tato podmínka se dá zvládnout správným ...
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 ...
A Comparison of Preconditioning Methods for Saddle Point Problems with an Application to Porous Media Flow Problems
Axelsson, Owe; Blaheta, Radim; Hasal, Martin
2016 - English
The paper overviews and compares some block preconditioners for the solution of saddle point systems, especially systems arising from the Brinkman model of porous media flow. The considered preconditioners involve different Schur complements as inverse free Schur complement in HSS (Hermitian - Skew Hermitian Splitting preconditioner), Schur complement to the velocity matrix and finally Schur complement to a regularization block in the augmented matrix preconditioner. The inverses appearing in most of the considered Schur complements are approximated by simple sparse approximation techniques as element-by-element and Frobenius norm minimization approaches. A special interest is devoted to problems involving various Darcy, Stokes and Brinkman flow regions, the efficiency of preconditioners in this case is demonstrated by some numerical experiments.
Keywords:
schur complements; linear-systems; high performance computing
Available at various institutes of the ASCR
A Comparison of Preconditioning Methods for Saddle Point Problems with an Application to Porous Media Flow Problems
The paper overviews and compares some block preconditioners for the solution of saddle point systems, especially systems arising from the Brinkman model of porous media flow. The considered ...
Composition and microstructure of plasters in convent of the Želiv Monastery (Czech Republic)
Rezek, P.; Martinec, Petr; Ščučka, Jiří; Majstríková, T.
2016 - English
The paper deals with analyses of composition and structure of historic plasters from the convent building of the Želiv Monastery (Czech Republic). Composition and microstructure of plaster samples taken from the historic object have been assessed using both traditional and advanced analytical methods. The following techniques have been used for the assessment of binders and fine aggregates in plasters: optical microscopy of thin sections, mineralogical and petrographic analysis of separated components, infrared spectroscopy, and thermal analysis. Presented results show significant differences in character of the studied materials of varying age and demonstrate the effectiveness of the taken analytical approach.
Keywords:
aggregate; thermal analysis; historic plaster; infrared spectroscopy; optical microscopy
Available at various institutes of the ASCR
Composition and microstructure of plasters in convent of the Želiv Monastery (Czech Republic)
The paper deals with analyses of composition and structure of historic plasters from the convent building of the Želiv Monastery (Czech Republic). Composition and microstructure of plaster samples ...
Teoreticko-metodologická východiska anticipace rizik brownfield managementu
Trojan, Jakub; Krejčí, Tomáš; Taraba, P.
2015 - Czech
Příspěvek je zaměřen na představení východisek teoreticko-metodologického charakteru, která formují metodiku anticipace rizik u velkých projektů v brownfields managementu. Předkládá poznatky odkazující se na již realizované mezinárodní projekty 7. rámcového programu (zejména prioritizační nástroj rozvoje brownfields) stejně jako z řešených projektů aplikovaného výzkumu v oblasti brownfields a soustředí se na deskripci základních tezí podávaného projektového záměru řešícího anticipaci rizik v oblasti brownfield managementu (TAČR, Omega, TD03000089). The paper is focused on presenting the theoretical and methodological basis shaping the methodology of anticipation of risk in the field of brownfields management. It analyzes the findings of already completed international projects under the 7th Framework Programme (especially the prioritization tool for development of brownfields) as well as results and proposals from completed projects of applied research in the field of brownfields. It also focuses on description of basic layout of proposed project from the field of risk anticipation in the brownfield management (TAČR, Omega, TD03000089).
Keywords:
risk analysis; brownfields; management
Available at various institutes of the ASCR
Teoreticko-metodologická východiska anticipace rizik brownfield managementu
Příspěvek je zaměřen na představení východisek teoreticko-metodologického charakteru, která formují metodiku anticipace rizik u velkých projektů v brownfields managementu. Předkládá poznatky ...
Regional and flash flood as a limiting factor for development
Kolejka, Jaromír; Krejčí, Tomáš; Rapant, P.; Inspektor, T.
2015 - English
Locating and developing factors are generally well known, studied and taken into account in the accepting of the solution. In contrast, the limiting factors of development usually stands in the background. Current data sources, knowledge and modelling technologies allow greatly anticipate the extent of the flood situation. Evaluation of the risk of regional or flash floods is not discouraging information for investors, but rather to guide their activities to a safe area. Knowledge of risk locations in the Czech Republic in terms of these types of floods also help for the safety of visitors and the local population. Appropriately incorporated findings into the development plans of all dimensions support the initiatives of local and external investors. The paper illustrates the unconventional use of public available geodata in the form of an offer vital information into regional development plans.
Keywords:
flood; regional development; limiting factors; natural hazard
Available at various institutes of the ASCR
Regional and flash flood as a limiting factor for development
Locating and developing factors are generally well known, studied and taken into account in the accepting of the solution. In contrast, the limiting factors of development usually stands in the ...
GEOSITE AND GEOMORPHOSITE ASSESSMENT FOR GEOTOURISM PURPOSE: A CASE STUDY FROM THE VIZOVICKA VRCHOVINA HIGHLAND, EASTERN MORAVIA
Kirchner, Karel; Kubalíková, Lucie
2014 - English
Geotourism can be understood at a broader sense as geographical tourism sustaining environment, culture, aesthetics, heritage and the well-being of residents of a place or in a more restricted sense as a form of nature tourism that specifically focuses on landscape and geology. Geological, geomorphological and pedological sites are the most important resource for the geotourism activities. It is evident that not every site can be used for geotourism purposes. To find out which site can be used, it is necessary to identify, describe and assess various sites using a suitable assessment methodology. Based on the definition and conceptsof geotourism and the assessment methods already used for geomorphosite assessment, authors propose five groups of assessment criteria. The method was used for assessing selected sites in the Vizovickavrchovina Highland (Eastern Moravia, Outer Western Carpathians). Thanks to the assessment of the sites in this region, some potential geotourism resources were identified. Although the proposed method is numerical which should reduce the subjectivity, there is always a degree of subjectivity due to the fact that the real value of some criteria cannot be measured and it depends on assessor's experience, knowledge and preferences.
Keywords:
geodiversity; geoheritage; numerical assessment; Outer Western Carpathians
Available at various institutes of the ASCR
GEOSITE AND GEOMORPHOSITE ASSESSMENT FOR GEOTOURISM PURPOSE: A CASE STUDY FROM THE VIZOVICKA VRCHOVINA HIGHLAND, EASTERN MORAVIA
Geotourism can be understood at a broader sense as geographical tourism sustaining environment, culture, aesthetics, heritage and the well-being of residents of a place or in a more restricted sense ...
Factors of revitalization of brownfields in the Czech Republic
Osman, Robert; Frantál, Bohumil; Kunc, Josef; Klusáček, Petr; Martinát, Stanislav
2014 - English
The paper deals with reuse of brownfields in the Czech Republic. Based on the analysis of information about re-use of residual spaces are shown major changes in the current management space. The paper is based on a comparison of two data files - specifically, the existing brownfields database managed by the CzechInvest and own database of brownfields that have already been revitalized. The paper is divided into three parts, the first part of the paper analyzes the structure of a revitalized brownfields, in the second part of the paper, the structure of this file is compared with the structure of existing brownfields and the third part analyzes the factors revitalization of brownfields. The paper aims to answer the question what functions take the brownfields after revitalization and what factors determine their reuse.
Keywords:
space management; revitalization; brownfield
Available at various institutes of the ASCR
Factors of revitalization of brownfields in the Czech Republic
The paper deals with reuse of brownfields in the Czech Republic. Based on the analysis of information about re-use of residual spaces are shown major changes in the current management space. The paper ...
Vybrané aspekty monitoringu tepelné expozice báňských záchranářů
Pavelek, Zdeněk
2014 - Czech
Zásahy báňských záchranářů ve ztížených mikroklimatických podmínkách patří mezi nejobtížnější a také nejrizikovější zásahové činnosti báňského záchranného sboru. Standardně používaná metoda monitoringu tepelné expozice báňských záchranářů spočívá v manuálním měření teplot (relativní vlhkosti) důlního ovzduší při cestě na pracovišti a na pracovišti samotném a dále ve sledování aktuálního tělesného stavu báňských záchranářů měřením jejich tepové frekvence. Z měření teplot (relativní vlhkosti) důlního ovzduší je následně tabelárně stanovována délka doby zásahu bez dýchacích přístrojů i s nasazenými dýchacími přístroji. Nové směry v monitoringu tepelné expozice báňských záchranářů s sebou přinášejí především akcentaci kontinuálního hodnocení aktuálního tělesného stavu každého jednotlivého zasahujícího báňského záchranáře, přičemž toto hodnocení je založeno na průběžném měřením fyziologických veličin tělesného organismu. Tento způsob monitoringu tepelné expozice báňských záchranářů představuje výrazné zvýšení míry bezpečnosti vedení zásahové činnosti báňského záchranné služby při hornické činnosti v hlubinných dolech. The responses of mine rescuers in worsened microclimatic conditions are among the most arduous and risky operations undertaken by mine rescue crews. The standard method of monitoring mine rescuers´ exposure to heat consists of manually measuring the temperature (relative humidity) of the mine atmosphere both en route and on site and further, of monitoring the actual physical condition of mine rescuers by measuring their pulse rate. From the measurement of the temperature (relative humidity) in the mine atmosphere, the duration of responses without wearing breathing apparatuses, or when wearing them, can subsequently be determined by means of tabulated values. New trends in monitoring the mine rescuers´ exposure to heat mainly accentuate continuous evaluation of the current physical condition of every individual mine rescuer in action, while this evaluation is based on continuous measurement of the physiological quantities of physical organism. This method of monitoring mine rescuers´ exposure to heat represents a significant improvement in safety when guiding responses of mine rescue services during mining activity in underground mines.
Keywords:
mine rescuers; worsened microclimatic conditions; risky operations
Available at various institutes of the ASCR
Vybrané aspekty monitoringu tepelné expozice báňských záchranářů
Zásahy báňských záchranářů ve ztížených mikroklimatických podmínkách patří mezi nejobtížnější a také nejrizikovější zásahové činnosti báňského záchranného sboru. Standardně používaná metoda ...
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