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Comparison choice cultural and weed kinds form stock Amaranthus
VÁLEK, Jan
Amaranthus (L.) belongs to among old cultural crops. Cultural forms of some species were already grown by Aztecs and Incs in ancient times. High nutritive value of seeds redounded to rediscovery of the crops. Tested varieties of cultural amaranth get to the interaction whit wild species of amaranth. This work would had contribute to better knowledge of ecology in the hybrid of cultural variety and weed (A. x turicensis = A. cruentus x A. retroflexus) The aim of this work was to describe production and morphometric characteristics of selected relative cultural and weed species of amaranth (Amaranthus hypochondriacus, Amaranthus cruentus, Amaranthus retroflexus), the hybrid A. x turicensis and to determinate occurrence and survival of weed species A. retroflexus onplaces, where cultural amarant was grown. A. retroflexus shows as a very resistant to damage. Cultural species responded on damage by reduction of majority observed parameters. Cultural species of amaranth responded more on different conditions substrate than the weed species. Response of hybrid on different substratum conditions was in the middle of spectrum of the response in cultural parents and the weed species. Indiference of the hybrid to substrate should be better clear up in the next studies. Weed species is little sensitive to competicion and his characteristics (total biomass, legth inflorescence, height of plants, number of leaves) are different not much. Effect of competition on hybrid shows his non - uniform response probably caused by his considerable variability Absence of cultural amarant and interspecific hybrids shows on relation of these plants to warmer weather that is probably the main factor for their occurrence.
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Historic Mortars - HMC 2010 and RILEM TC 203-RHM final workshop
Válek, Jan ; Groot, C. ; Hughes, J.
The HMC2010 conference and TC 203-RHM final workshop took place in Prague 22-24 September 2011. The event was organised by the Institute of Theoretical and Applied Mechanics of the Academy of Sciences of the Czech Republic (ITAM AV ČR) in cooperation with RILEM. The conference was chaired by J. Válek of ITAM. The final workshop was chaired the TC 203-RHM chairman and its secretary C. Groot of TÚ Delft and J. Hughes of University of the West of Scotland. Members of the TC 203-RHM were acting also as the International Scientific Committee members of the conference. The HMC2010 Organising Committee was composed of the staff members of ITAM AV ČR. The event was attended by 190 participants from 30 countries. Such a number of participants was regarded as a great success considering its rather narrow and specific scope and also the fact that it was only the 2nd conference in this future to be regular series.
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Study of historic mortars - Inspiration for the lime industry?
Válek, Jan
Study of historic mortars is motivated by the desire of understanding of these materials and also by the contemporary approach towards repair of architectural heritage. Detailed study contributes to new scientific findings for example about durability of materials and their degradation agents. Results of study of historic mortars can be an inspiration for production of modern lime based mortars. The focus on authenticity and understanding of historic materials leads to a reintroduction of production of some binders for repair of historic buildings. The 2nd Historic mortars conference joined with the RILEM TC 203-RHM - Repair mortars for historic masonry -was held in Prague earlier this year. This paper refers about selected contributions of this conference.
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Tests for desing of mortars and renders compatible with existing historic material
Válek, Jan ; Slížková, Zuzana
Design of masonry mortars and renders for repair of historic structures includes tests and testing procedures which serve for evaluation of compatibility between existing material and repair mixtures. Paper describes current possibilities of tests and analysis of historic and new mortars. The authors stem from published definitions of compatibility and emphasize a necessity to take into account also more detailed technical specifications, e.g. position of evaluated material in structure, type of structure, material exposure conditions, degree of deterioration of material and its ability to serve its original function.
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