Technology for Machining Bearing End Shield

Bakalářská práce je zaměřena na racionalizaci procesu výroby ložiskového štítu. V teoretické části je sestavena přehledná rešerše zabývající se aspekty a technologií obrábění. Praktická část byla orientována na konkrétní výrobu ložiskového štítu ve strojírenském podniku s navrženými podmínkami obrábění. Pro ověření nastavení řezných podmínek byla výroba realizována na CNC (SPR - 100). Dále byl v práci vylepšen dosavadní technologický postup. V závěru práce je vyhodnocena ekonomická stránka výroby a srovnána efektivnost ke stávajícímu technologickému postupuThis thesis deals with processing of the bearing shield. On production of this component is used CNC lathe from SPR - 100. There is described a technique for a specific machine together with presentation of the tools and products. The theoretical part deals with explaining concepts in the field of machining. Furthemore, there is pointed out the material and semifinished casting. In the practical part is designed the most suitable method for manufacturing the bearing shields with regard to the economic aspect of the production.346 - Katedra obrábění, montáže a strojírenské metrologievelmi dobř

Analysis of mining heritage of Příbram region

Katedra sociální geografie a region. rozvojeDepartment of Social Geography and Regional Develop.Faculty of SciencePřírodovědecká fakult

Experimental seismic measurement on the testing construction and the analyze

Konstrukce „stand“, která byla postavena v areálu Fakulty stavební, VŠB-TU Ostrava, má sloužit k realizaci experimentů a měření z různých oblastí stavitelství. Katedra geotechniky a podzemního stavitelství mimo jiné na konstrukci „standu“, konkrétně na železobetonových základových pásech, prováděla experimentální seizmické měření odezvy vibrační desky. Byl sledován útlum vibrací v prvních metrech od základu, získané záznamy byly vyhodnoceny v amplitudové i frekvenční oblasti a bylo provedeno zhodnocení na základě ČSN 73 0040. Součástí příspěvku je také možný návrh přístupu k analýze odezvy konstrukce na účinky vibrací za pomoci 3D matematického modelu vytvořeného programem SCIA Engineer 2011.1.Construction test „stand”, which was built on the premises of the Faculty of Civil Engineering, Technical University of Ostrava, is intended to implement the experiments and measurements from different areas of engineering. Department of Geotechnics and Underground Engineering carried out experimental measurements of seismic response of plate tamper on concrete strip footing of the construction test „stand”. Vibration attenuation was observed in the first meters from foundation constructions, obtained records were analyzed in amplitude and frequency domain and an evaluation based on ČSN 73 0040. Part of this paper is also possible approach to the response analyze of the structure to the effects of vibration using 3D mathematical model created by SCIA Engineer 2011.1

Dark side of the fence: ornamental plants as a source of wild-growing flora in the Czech Republic

Ornamental plants constitute an important source of alien, and potentially invasive species, but also include a substantial part of native flora and consist of taxa that occur both in the wild and in cultivation; yet garden floras are largely ignored in ecological studies.We studied ornamental plants in the Czech Republic in order to provide detailed information, based on field sampling, on the diversity of taxa grown in cultivation in private gardens. Sampling was done in accessible public areas, private gardens and private areas in villages, town- and city neighbourhoods, garden allotments, cemeteries, areas of dispersed farmhouse settlements not accessible to the public, and in new urban sprawl. The data can be used to estimate the propagule pressure of individual taxa, measured in terms of the frequency with which they are planted in the gardens. To make the data comparable across sites, we adopted a two-level approach that resulted in producing a detailed list (including all the taxa recorded) and an aggregated list (merging closely related and similar taxa, which was necessary in order to assess the frequency of planting across sites). Each species on the detailed list was assigned an origin, status, life history and cultivation requirements. Comparing the field records with national checklists of both native and alien vascular plants we quantified particular components of the ornamental flora. The floristic inventories for 174 sites yielded 1842 taxa on the detailed list, consisting of 1642 species (standard binomials), 9 cultivars assigned to genera, 147 hybrids and hybridogenous taxa, and 44 taxa identified at higher than species level. Of these taxa 1417 (76.9%) were alien and 420 (22.8%) native. The ornamental flora consisted of not-escaping aliens, escaping aliens and cultivated natives. Of the recorded taxa, 841 (45.6%) occur both in cultivation and the wild. The aggregated list comprised 1514 taxa and resulted from merging 533 taxa from the detailed list into 205 taxa. Most alien ornamentals are native to Asia and Americas. The proportion of escaped and not-escaping aliens significantly differed from wild aliens in the spontaneous flora with underrepresentation of escaped, which originated from Australia, Africa and the Mediterranean area. Taxa from Africa and anecophytes were overrepresented and those from Australia, the Mediterranean and other parts of Europe underrepresented among not escaping aliens. The assessment of planting frequency revealed that 270 taxa were found at more than 25% of the sites, while 584 (40%) occurred at only one or two sites.Winter annuals and shrubs are most represented among the commonly planted aliens; the only native species with comparably high planting frequencies among the aliens, are Vinca minor, Hedera helix and Aquilegia vulgaris. Related to the invasion potential of ornamental garden flora we analysed the recorded taxa with respect to the transient/persistent character of their occurrence. The core (persistent) part of the flora comprised 599 taxa (32% of the total number of taxa) and the transient 240 (13%) taxa. The “grey zone” between the two included 1003 taxa (55%). The results reported here provide quantitative insights into the role of horticulture as a major pathway of plant invasions

Výplň týlní deprese sesuvu mezi Židlochovicemi a Blučinou na severozápadním okraji Výhonu

The studied area is located in a small basin between between Strže („Cézavy“) and Výhon hills. The „Cézavy“ site is an important Bronze Age enclosed settlement. Geological setting was examined by coring and electric resistivity tomography. Selected horizons were dated by C14 method. Holocene infill of basin is composed of two sedimentary units: intra-basin facies of dark coloured lacustrin-swamp clayey-silty sediments and marginal facies of clayey-silty-sandy sediments. Basin of assymetrical shape is deepest near foothill of „Cezávy“, where started infilling of basin as soon as ~3600 BP or earlier. The basin is delimited by bodies of Miocene rocks. Geochronological model shows existence of swamps-lacustrine basins in a time span since 17th century BC till 18th centuriy AD. It indicates, that main cause that filled the basin is individual landslides. Every landslide event caused new spatial configuration of basins and elevations. Last significant events were probably extensive, historically recorded landslides in 70‘s of 18th century. Recent morphology was formed as late as in 19th century

Forest microclimate dynamics drive plant responses to warming

Climate warming is causing a shift in biological communities in favor of warm-affinity species (i.e., thermophilization). Species responses often lag behind climate warming, but the reasons for such lags remain largely unknown. Here, we analyzed multidecadal understory microclimate dynamics in European forests and show that thermophilization and the climatic lag in forest plant communities are primarily controlled by microclimate. Increasing tree canopy cover reduces warming rates inside forests, but loss of canopy cover leads to increased local heat that exacerbates the disequilibrium between community responses and climate change. Reciprocal effects between plants and microclimates are key to understanding the response of forest biodiversity and functioning to climate and land-use changes

Observer and relocation errors matter in resurveys of historical vegetation plots

Aim: Revisits of non-permanent, relocatable plots first surveyed several decades ago offer a direct way to observe vegetation change and form a unique and increasingly used source of information for global change research. Despite the important insights that can be obtained from resurveying these quasi-permanent vegetation plots, their use is prone to both observer and relocation errors. Studying the combined effects of both error types is important since they will play out together in practice and it is yet unknown to what extent observed vegetation changes are influenced by these errors. Methods: We designed a study that mimicked all steps in a resurvey study and that allowed determination of the magnitude of observer errors only vs the joint observer and relocation errors. Communities of vascular plants growing in the understorey of temperate forests were selected as study system. Ten regions in Europe were covered to explore generality across contexts and 50 observers were involved, which deliberately differed in their experience in making vegetation records. Results: The mean geographic distance between plots in the observer+relocation error data set was 24m. The mean relative difference in species richness in the observer error and the observer+relocation data set was 15% and 21%, respectively. The mean pseudo-turnover between the five records at a quasi-permanent plot location was on average 0.21 and 0.35 for the observer error and observer+relocation error data sets, respectively. More detailed analyses of the compositional variation showed that the nestedness and turnover components were of equal importance in the observer data set, whereas turnover was much more important than nestedness in the observer+relocation data set. Interestingly, the differences between the observer and the observer+relocation data sets largely disappeared when looking at temporal change: both the changes in species richness and species composition over time were very similar in these data sets. Conclusions: Our results demonstrate that observer and relocation errors are non-negligible when resurveying quasi-permanent plots. A careful interpretation of the results of resurvey studies is warranted, especially when changes are assessed based on a low number of plots. We conclude by listing measures that should be taken to maximally increase the precision and the strength of the inferences drawn from vegetation resurveys

Replacements of small- by large-ranged species scale up to diversity loss in Europe’s temperate forest biome

The loss of biodiversity at the global scale has been difficult to reconcile with observations of no net loss at local scales. Vegetation surveys across European temperate forests show that this may be explained by the replacement of small-ranged species with large-ranged ones, driven by nitrogen deposition. Biodiversity time series reveal global losses and accelerated redistributions of species, but no net loss in local species richness. To better understand how these patterns are linked, we quantify how individual species trajectories scale up to diversity changes using data from 68 vegetation resurvey studies of seminatural forests in Europe. Herb-layer species with small geographic ranges are being replaced by more widely distributed species, and our results suggest that this is due less to species abundances than to species nitrogen niches. Nitrogen deposition accelerates the extinctions of small-ranged, nitrogen-efficient plants and colonization by broadly distributed, nitrogen-demanding plants (including non-natives). Despite no net change in species richness at the spatial scale of a study site, the losses of small-ranged species reduce biome-scale (gamma) diversity. These results provide one mechanism to explain the directional replacement of small-ranged species within sites and thus explain patterns of biodiversity change across spatial scales