National Repository of Grey Literature 1,004 records found  1 - 10nextend  jump to record: Search took 0.06 seconds. 


Reinforcing grouting in coal seams
Souček, Kamil ; Šňupárek, Richard
Chemical grouting is very effective in coal mining. The paper summarises experience with chemical grouting for stabilisation and reinforcing of underground openings.

Perfectly matched layer as a boundary condition for modelling dielectric waveguide structures
Čtyroký, Jiří
Physical principle of the "perfectly matched layer" as a boundary condition for numerical modelling of open waveguide problems is explained. As an example, spectral properties of waveguide grating are calculated using the mode matching method with perfectly matched layers as a boundary condition.

Residential Complex in Brno - Komín
Ertl, Jakub ; Čelikovský, Martin (referee) ; Makovský, Zdeněk (advisor)
Urban Risen Solution parcel located on the street Pasture in the city of Brno chimney. The property is located on the edge of the city district and directly continues the surrounding forest, which is on the east side. The plot is an avenue of chestnut trees that proposal preserves intact. Oklí are good amenities. In its narrowest surroundings there are elementary school and kindergarten with their priľahlími Sports and satellites family townhouses on the south side of the property. After the eastern and northern boundary leads IMPORTANT relaxing walking routes on which the proposal responds through-beds, and a "restoration" of pastures, which once was located here. Land would extend that oľúbenú Walking and served by community residents as well as the city of the chimney. The project also own community náveznosťou room with a plate of street furniture. Architectural design Material objects based on the elongated shape of the land and is divided into three apartment buildings. Distributes land to the "street" and the "grazing". The volume responds to building orientation sides are angled wings housing the south and west. All the apartments are so perfect sunlit and overlook the "pasture". On the north side of the building they are arranged in the form of communication zasklennej galleries. The porch with loggias flats made up of separate steel structure, which forms the form of these apartment buildings. The main module becomes one living room, ensuring good housing variability. The building is located only forty apartments of sizes 1 + kk to 5 + kk apartment with terrace. Parking is in the combined form of overhead and underground parking. Building Solutions The building is designed as a reinforced concrete skeleton with dimensions of 8600 mm x 6600 mm with stiffening communication core. The shell is insulated with thermal insulation with a thickness of 200 mm. Area building openings is minimized on the north facade and vice versa is open to south and west facades, which benefits the passive energy gain. These construction holes are filled with high quality aluminum windows and doors with Triple glazing. On the frame is attached a separate steel construction porches and balcony. This concept allows a perfect insulation shell fired by a separate steel structures unheated porch and balcony, and hence a considerable degree of energy efficiency.

Contactless measurement of surface temperatures when machining
Šťáva, Radek ; Sliwková, Petra (referee) ; Polzer, Aleš (advisor)
Contactless measuring of surface temperature integration in the other measurement methods and their assimilation at evaluation of surface temperature of a semi-finished product bored by various tools is the target of the work. An impassable opening is being bored by these tools. The opening is close to a scanned wall. The semi-finished wall temperatures are being scanned by thermocamera and subsequently compared for every single used tool in this experiment.

Summary of foreign knowledge about the origin and development of EDZ in crystalline rocks - research
Vavro, Martin ; Souček, Kamil ; Staš, Lubomír ; Vavro, Leona
Presented search summarizes findings of foreign research oriented on the origin and evolution of the excavation damaged zone in crystalline rocks with a particular focus on the essential results of experimental projects which were performed in Canada, Sweden, Finland, and Switzerland. The study is divided, excluding the introduction, into seven main chapters of the text, which gradually deal with: (1) definition of key terms, (2) overview of the main underground research laboratories in the world where EDZ assessment was conducted, (3) methods suitable for EDZ description and characterization, (4) main factors influencing the origin of failure around the excavations and time-dependent evolution of EDZ. An overview of important outcomes of EDZ experiments, focusing on the European hard rock laboratories (Stripa, Äspö, Onkalo/Olkiluoto and Grimsel), and their summary are presented in the final two chapters.\nThe review summarizing the published key findings and results of in situ experiments shows, that for rock in lower stress state, i.e. in no spalling environment, the extent and character of rock mass damage is typically dependent on the excavation method. Using mechanical excavation, rock damage zone with thickness less than 3 centimeters can be originated. The microcracks within this zone contribute to the increase of hydraulic conductivity of the rock mass. At some test sites (Äspö, Grimsel), where the tunnel boring machine technology was used, the damage zone was already detected in depth of less than 5 mm.\nOn the contrary, openings excavated by drilling and blasting are characterized by much more extensive damage zones up to several tens of centimeters in width. The damage progressively diminishes with the distance from the opening.

Organized Nanostructured TiO2 Materials: Synthesis, Characterization, Applications
Zukalová, Markéta ; Rathouský, Jiří (advisor) ; Mička, Zdeněk (referee) ; Šubrt, Jan (referee)
CONCLUSIONS It has been known for a long time that material properties change on the nanoscale and are different from those of single crystals or conventional microstructured, monolithic or composite materials32. The presented thesis aimed at demonstration of the diversity in these properties for various morphologies of TiO2. Despite the fact that the chemical composition is identical, the structure of different morphologies matters and it is respon-sible for their specialty. The successfully mastered syntheses of desirable particle size materials open the pathway towards applications taking advantage of size dependent properties. DSC employing 2μm mesoporous TiO2 film as a photoanode exhibited the solar conversion efficiency as high as 4.63% due to the large surface area (roughness fac-tor). Optimized pore size together with the framework consisting of anatase nanocrystals are responsible for the high dye adsorption capacity improving the performance. Incorporating an additional inverse opal layer in DSC represents an example of its further possible upgrade. This optimized set up can increase the short circuit photocurrent effi-ciency of this device of about 26 % (Ref.39). Owing to the diffusion coefficient of an order of 10-13 cm2/s for microcrystalline spinel and even less for nanocrystalline spinel...

Study for reclamation plan for open-pit sand mining area of Pískovna and Na Jatkách at Brandýs n. L.-Stará Boleslav
Prášek, Přemysl ; Novotný, Vojtěch (advisor) ; Jindřiška, Jindřiška (referee)
This bachelor thesis concerns with reclamation of post-mining areas that are in direct contact with inhabited areas. Based on a literature review it proposes a new solution for reclamation of areas Pískovna and Na Jatkách at Brandýs nad Labem-Stará Boleslav municipality. The proposal attempts to be a consensus between the reclamation plan of the mining company, the requirements of nature and flood protection and the recreational needs of the residents of the municipality. Based on the above, the bachelor thesis proposes changes to current Land use plan of the municipality.

Ecological and evolution strategies of necrophagous beetles (Coleoptera)
Jakubec, Pavel ; Růžička, Jan (advisor) ; Petr, Petr (referee)
Necrophagous beetles (Coleoptera) are very interesting and diverse ecological group of species with an immense impact on a natural nutrient cycle. Their main food source and breeding ground are carrions of vertebrates, human remains included. This relationship is often used in various ways by forensic entomology, but its potential was not jet fully reached, because our knowledge of biology and ecology of these beetles is very much incomplete. In this thesis I would like to explore geographic distribution, ecological requirements and developmental biology of several Central European necrophagous beetles as an outcome of their ecological and evolution strategies. For that I raised three broad research questions. Which factors are determining the local abundance of carrion beetles (Coleoptera: Silphidae)? How the current geographical distribution of open-landscape carrion beetles looks like in the Czech Republic? How the temperature affects the development of Sciodrepoides watsoni (Spence, 1813)? We found out that soil type can have significant effect on abundance of carrion beetles. They showed preference for chernozem -- Nicrophorus antennatus (Reitter), N. germanicus (Linnaeus), N. interruptus (Stephens), N. sepultor (Charpentier), Silpha obscura obscura (Herbst), T. sinuatus (Fabricius) or for fluvisol as did N. humator (Gleditsch). These findings support our hypothesis that soil type could be an important factor determining the occurrence of necrophagous European carrion beetles. To collect novel data of the current geographical distribution of carrion beetles we used 420 baited pitfall traps at 84 localities, and we collected 71 234 specimens of 15 silphid species. Among them, three endangered carrion beetle species listed on the Czech Red List of Invertebrates, were found. Two are vulnerable thermophilic species of open landscapes, Nicrophorus antennatus (Reitter, 1884) (collected around Louny and Židlochovice) and Nicrophorus germanicus (Linnaeus, 1758) (Louny, Zábřeh and Židlochovice). The third is the near threatened species, Nicrophorus sepultor Charpentier, 1825 (collected around Louny, Kutná Hora, Zábřeh and Židlochovice), which also prefers open landscapes. We studied development of common Holarctic beetle Sciodrepoides watsoni under five constant temperature regimes in laboratory (15, 18, 21, 25 and 28°C). Parameters of thermal summation models and their standard errors were calculated for each developmental stage (egg, three larval instars and pupae). We also find a new character for larval instar determination (head width) and proposed novel approach for future studies of size-based characters in instar determination.

Analysis of selected factors affecting occurrence of Chalara fraxinea in the environment.
Havrdová, Ludmila ; Šrůtka, Petr (advisor) ; Jaroslava, Jaroslava (referee)
Extensive investigation of ash dieback impact on different rural vegetation types (solitaires, scattered plantations, riparian stands, scree- and ash-alder alluvial forests) was performed in the Lusatian Mts. (the Czech Republic) between 2011 and 2013. The rate of ash dieback and 27 environmental variables were investigated in 80 research plots with a total of 1045 evaluated trees. The developed model (GLM) explained ca 27% of the disease variability. Particular models for each vegetation type importantly differed from each other and explained 28--46% of the disease variability. The variables that positively affected the disease impact included the host crown area, ash area and rate of ash in the stands, tree layer area, canopy closure, north aspect, shrub and herbaceous layer canopy, vertical heterogeneity and standard deviation of TPI. Tree height, the distance and damage of the nearest host as well as the water source distance, slope and its standard deviation affected it negatively. The coincidental attack of the trees by Armillaria sp. and Hylesinus fraxini positively affected the disease progress, whereas the presence of Nectria sp. and Aceria fraxinivorus conclusively decreased progress, most likely via the induction of secondary metabolites. The highly conclusive regression of ash dieback on the number of days with an air humidity of >95% between 6--11 a.m. in the main period of ascospore spread was identified. Because the air humidity near the ground was highly affected by local factors, a GLM model explaining the variability of air humidity with that of investigated factors was developed. This model explained 77% of the variability attributed to air humidity, local factors (TPI and SD of TPI, aspect, slope, altitude, distance from open water, tree and shrub layers canopy, tree stand height, etc.) greatly affected the disease impact related to air humidity. The landscape form was identified as a factor (most likely via air humidity) that affects the impact of the disease -- for example, the stands on mountain tops and slopes were less affected than the stands in valleys. The vegetation types highly differed in the disease extent. In general, the solitaires and scree forests were significantly less damaged than mixed ash-alder forests and riparian stands. The smaller stands were less affected than the more extended, the stands enclosed in canopy of other forests were less damaged than comparable vegetation in open landscapes and stands with higher humidity (riparian stands and mixed ash-alder forests) were more damaged than those without water. The outcome clearly supports the possibility of development and usefulness of appropriate forest and landscape management of the disease.