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Inner Structure of Functionala Region: Theoretical Aspects
Erlebach, M.; Klapka, Pavel; Halás, M.; Tonev, P.
2014 - English
The contribution addresses theoretically the inner structure of functional region. It defines types of functional regions on the basis of selected criteria regarding their inner structure. As classification criteria a number of cores in a region, their hierarchical importance and ch aracter of interaction relationships between them and within a region have been employed. A study of functional regions is not important only for geography, but also for regional and spatial science and for planning practise.
Keywords:
functional region; inner structure; types of regions
Fulltext is available at external website.
Inner Structure of Functionala Region: Theoretical Aspects
The contribution addresses theoretically the inner structure of functional region. It defines types of functional regions on the basis of selected criteria regarding their inner structure. As ...
Texture of cokes in relation to parameters of coal and coke
Pěgřimočová, J.; Kožušníková, Alena
2013 - English
The article presents a proposal of the simplified classification of textures of coke and the relationship between the texture parameters of coke both coal, from which the coke was made, and properties of the coke.
Keywords:
texture of cokes; coal; phase carbon forms
Available in a digital repository NRGL
Texture of cokes in relation to parameters of coal and coke
The article presents a proposal of the simplified classification of textures of coke and the relationship between the texture parameters of coke both coal, from which the coke was made, and ...
Pulsed liquid jet generated by pulse multiplication technique
Dvorský, R.; Sitek, Libor; Sochor, T.
2013 - English
First theoretical papers summarizing the high mechanical energy cumulation when high-speed drops impacting the solid surface as a result of the water hammer effect have been known since 1960’s. Heymann has demonstrated that pressure maximum in the impact of a spherical drop of a liquid is several times higher than the presupposed maximum for the classical water hammer effect. The latter maximum pressure itself exceeds the mere stagnation pressure of the continuous jet many times hereat. When developing devices for pulse jet generation a new generalization of the classical water hammer theory for high pressures has been implemented. Based on this the new patented principle of “pulse multiplication” has been formulated. The pulse multiplier is the source of high-pressure pulses with 100% depth of modulation of liquid jet discharge velocity that allows increasing the jet disintegration effect significantly without the abrasive material application.
Keywords:
pulse liquid jet; water hammer effect; pulse intensifier; high-pressure pulses
Available in a digital repository NRGL
Pulsed liquid jet generated by pulse multiplication technique
First theoretical papers summarizing the high mechanical energy cumulation when high-speed drops impacting the solid surface as a result of the water hammer effect have been known since 1960’s. ...
Preliminary analysis of volume material removal at bone cement disintegration by pulsating water jet
Lehocká, D.; Hloch, S.; Foldyna, Josef; Monka, P.; Monková, K.; Brezíková, K.
2013 - English
The article deals with preliminary analysis of material removal during disintegration of bone cement. This article was created to show possibilities of pulsating water jet utilization in medicine. Experiments with pulsating water jet were done using two types of nozzles - flat and round. Traces in bone cement were measured by optical profilemeter MicroProf FRT. Results show that pulsating water jet will be possible focuses as a tool for medical purposes, but further detailed research is needed.
Keywords:
pulsating water jet; PMMA - bone cement; volume removal
Available in a digital repository NRGL
Preliminary analysis of volume material removal at bone cement disintegration by pulsating water jet
The article deals with preliminary analysis of material removal during disintegration of bone cement. This article was created to show possibilities of pulsating water jet utilization in medicine. ...
Research on effects of pulsating water jets on concrete
Sitek, Libor; Bodnárová, L.
2013 - English
An article briefly presents results achieved during laboratory and in-situ tests of removing surface layers of concrete exposed to various environments using several types of high-velocity water jets commonly used in the rehabilitation praxis or advanced water jets the use of which is expected in the near future. The effects of pulsating jets were always compared with classical continuous jets under identical or similar working conditions.
Keywords:
degraded concrete; structure rehabilitation; concrete surface; pulsating water jet
Available in a digital repository NRGL
Research on effects of pulsating water jets on concrete
An article briefly presents results achieved during laboratory and in-situ tests of removing surface layers of concrete exposed to various environments using several types of high-velocity water jets ...
Removal of polyurea spray coatings from the surface of cement concrete by water jet technology
Ščučka, Jiří; Bódi, Z.; Hlaváček, Petr; Klich, Jiří; Martinec, Petr; Foldyna, Josef
2013 - English
The paper is focused on the removal of polyurea spray coatings from the surface of cement concrete by the water jet technology. A series of experiments was conducted to disintegrate a defined polyurea spray coat layer on the surface of cement concrete tiles using different configurations of the water jet system. The results of these experiments have confirmed that the continuous water jet was highly effective in removing the spray coat, causing no damage to the concrete substrate underneath. The partial experimental results have also indicated that this process can be used to produce an anti-skid finish on polyurea spray coatings applied onto horizontal structures.
Keywords:
concrete; polyurea spray coating; removal; water jet
Available in a digital repository NRGL
Removal of polyurea spray coatings from the surface of cement concrete by water jet technology
The paper is focused on the removal of polyurea spray coatings from the surface of cement concrete by the water jet technology. A series of experiments was conducted to disintegrate a defined polyurea ...
Relief assessment methodology with respect to geoheritage based on example of the Deblínská vrchovina Highland
Kirchner, Karel; Kubalíková, L.
2013 - English
The article deals with history, presence and possible future development of geoconservation in the Czech Republic. Both examples of legislative instruments and other geoconservation activities are presented. Practically, the geoconservation activities are shown at the case study of the central part of the Deblínská vrchovina Highland (Maršov valley area) in the south-eastern part of the Czech Republic.
Keywords:
geoheritage; geomorphosites assessment; Maršov valley
Fulltext is available at external website.
Relief assessment methodology with respect to geoheritage based on example of the Deblínská vrchovina Highland
The article deals with history, presence and possible future development of geoconservation in the Czech Republic. Both examples of legislative instruments and other geoconservation activities are ...
Measurement and evaluation of pulsating water jet peening intensity
Hlaváček, Petr; Klich, Jiří; Foldyna, Josef; Sitek, Libor
2013 - English
Pulsating water jet peening is a promising method in surface treatment. It has the potential to induce compressive residual stresses that benefit the fatigue life of components similar to the other peening process. In this paper experimental results obtained by action of pulsating water jet on Almen strips are presented.
Keywords:
pulsating water jet; peening intensity; Almen strips
Available in a digital repository NRGL
Measurement and evaluation of pulsating water jet peening intensity
Pulsating water jet peening is a promising method in surface treatment. It has the potential to induce compressive residual stresses that benefit the fatigue life of components similar to the other ...
Research on waterjet in Institute of Geonics of the AS CR from 1990 to 2006
Vašek, Jaroslav
2013 - English
The paper is continuation of an article published in the proceedings of the conference "Water Jet 2011 - Research, Development, Applications”. By 1990, the work is briefly described in the article (VAŠEK 2011). The follow-up work carried out in the period 1990 - 2006 is the subject of this article. The paper gives a brief overview of the author's participation at the World Mining Congress in Beijing (1990), a collaboration with CNR Canada, CNR Cagliari (Italy), the organization of international conferences GEOMECHNICS 91, 93 and 96. The cooperation with University of Missouri Rola (hereinafter UMR) USA, Cornerstone Technologies and Pennsylvania Micronics, cooperation within the project EU-Inco Copernicus (1995 - 1999) and the project of Grant Agency of the Academy of Sciences of the Czech Republic (hereinafter GAAV) "Mechanical breakages and disintegration processes of coal and rock - theoretical aspects, applications, outlook” (2001-2006) are also presented.
Keywords:
water jet; history; period 1990 - 2006
Available in a digital repository NRGL
Research on waterjet in Institute of Geonics of the AS CR from 1990 to 2006
The paper is continuation of an article published in the proceedings of the conference "Water Jet 2011 - Research, Development, Applications”. By 1990, the work is briefly described in the article ...
Thermal behaviour of organically modified clays
Plevová, Eva; Vaculíková, Lenka; Vítámvásová, E.; Šugárková, Věra; Martynková, G.S.
2013 - English
The clay minerals were modified by two alkylammonium cations under sorption procedure. T X-ray powder diffraction and FT-IR spectroscopy were used to evaluate the intercalation process of organic cations int the clay structure. The organo - montmorillonites exhibited IR spectra giving evidence about sorption or intercalation of the alkylammonium cations. The enhancement of the basal spacing obtained by X-ray diffraction confirmed the intercalation process of cations into montmorillonite and vermiculite samples. Thermal behaviour of the modified clay minerals was investigated by simultaneous thermogravimetry and differential thermal analysis. The organically modified montmorillonites exhibited the higher values of temperatures related to the total melting. Also the temperatures of exotherm effects connected to recrystallization and transformation increased with the concentration of alkylammonium salts. The temperatures of dehydratation and dehydroxilation decreased with concentration of alkylammonium cations. Vermilulite samples showed generally reducing of their thermal stability.
Keywords:
clay minerals; alkylammonium cations; intercalation; thermal analysis
Available in a digital repository NRGL
Thermal behaviour of organically modified clays
The clay minerals were modified by two alkylammonium cations under sorption procedure. T X-ray powder diffraction and FT-IR spectroscopy were used to evaluate the intercalation process of organic ...
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