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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Rozpoznávání a klasifikace polygonálních struktur mrazových klínů z dat DPZ / Recognition and classification of patterned ground polygons from remote sensing data

Kříž, Jan January 2013 (has links)
Recognition and classification of patterned ground polygons from remote sensing data Abstract The main objective of this thesis has been to prove the possibility of using object based image analysis classification for identification of the ice-wedge polygons and to find general method for their classification. The thesis contains a comparison of the object based and pixel based classification of the subject. The three classification rulesets for OBIA were developed on three test sites on Mars captured by HiRISE sensor. As a result, the general classification approach is suggested. The manually collected datasets, which are common in geomorphological research, were used as the reference sample. The OBIA classification provided better results in all three cases, whereas the pixel classification was valid in only one case. Another objective has been the automatization of the process of gaining information about morphometric characteristics of the ice-wedge polygons and the subsequent classification of the polygons. Within the scope of the process were developed methods for creating polygonal network and specified parameters of those methods. Several toolboxes for the ArcGIS software were prepared and they are part of the results of the thesis. Keywords: patterned ground, ice-wedge polygons, remote sensing,...
2

Navrhování konstrukcí vozovek pomocí dimenzačního programu Alize / Design of road constructions with the programme Alize

Grošek, Jiří January 2013 (has links)
This master’s thesis deals with the analysis of stress, fatigue and the assessment of frost effects in program ALIZE as it is prescribed in norm NFP 98-086 and comparing with the regulation TP 170 Designing roadways of roads and program LayEps.
3

Polohové a morfometrické charakteristiky polygonů mrazových klínů na Marsu / Spatial and morphometric features of thermal contraction crack polygons on Mars

Žížalová, Ivana January 2019 (has links)
The aim of this thesis is to analyze zonality of the thermal contraction crack polygons on the surface of Mars. Their morphology and its variation are analyzed in relation to the latitude of Mars. For spatial and morphological analysis were selected 64 images from the HiRISE (Mars Reconnaissance Orbiter) polychromatic camera dataset, images are covering the bandwidths proportionally. Images were first visually analyzed using HiView. 258 areas containing the thermal contraction crack polygons (with total area of 1184 km2 ) and 1036 well developed thermal contraction crack polygons were further vectorized using ArcMap. The thermal contraction crack polygons were found in every searched latitude which proves the ubiquity of permafrost. The largest amount of the thermal contraction crack polygons have been found in latitudes ±60ř and 45ř. In these latitudes were also found the largest and probably the deepest thermal contraction crack polygons (average length ranges from 42,1 - 73,6 m). The smallest polygons (average length 7,7 m) were found around the equator. "Altitude" has no effect on the spread of the thermal contraction crack polygons on Mars; however it has the effect on its morphology. The most widespread are pentagonal polygons, which occur mainly in the southern hemisphere. The next most...
4

Sledování odolnosti proti mrazu a vodě stmelených směsí do pozemních komunikací / Resistance to freezing and thawing of hydraulically bound mixtures to roads

Švantner, Lukáš January 2014 (has links)
The theoretical part of this master’s thesis contain comparing the methods of endurance hydraulic bound mixtures of concrete recycles against influence of water and freeze in Czech republic and some other states of The European Union. The practical part is dedicated about laboratory testing concrete recycles with mixtures of binders and its endurance against the water and freeze cycles in Czech republic. In made rollers is compared the strength in pure compression with the strength in pure compression after freezing cycles. From the results of the exams is considered about suitability of using these hydraulic bound mixtures to road construction depending on the kind of use binder, amount of the binder and water. Results of this thesis will be used to revision of national postscript of technological norm ČSN 73 6124-1.
5

Morfologie fosilních tříděných strukturních půd Krkonoš / Structure of non-active sorted patterned ground in the Giant Mts.

Uxa, Tomáš January 2011 (has links)
Sorted patterned ground are a group of periglacial microforms which create more or less symmetrical forms due to frost action and especially repeated freeze-thaw cycles. The origin of sorted patterned ground in the Giant Mts. is presumed in late Pleistocene and they are suggested to be recently inactive (with the exception of sorted circles). Their occurrence is linked to the topmost localities with flat surfaces and intense wind action which causes low snow cover and allow deep soil freezing. The submitted diploma thesis deals with the influence of site characteristics (such as microclimatic extremity, terrain morphology and lithology) on morphology and sorting degree of sorted patterned ground. Field research was carried out along a transect tracing the microclimatic extremity gradient (represented by altitude and so-called relative snow height) in area of Mt. Luční hora in the eastern part of the Giant Mts. which in relatively homogeneous from the viewpoint of lithology and wind exposure. The transect was further extended across the Modré sedlo Saddle to the Mt. Studniční hora where there also occur various types of fossil sorted patterned ground or quasi- active sorted circles in the Modré sedlo Saddle, respectively. However, there is a variability of lithological as well as altitude...
6

Nízkoteplotní vlastnosti asfaltových pojiv a směsí / Low temperature properties of asphalt binders and mixtures

Veselý, Petr Unknown Date (has links)
Today’s society is highly reliable on a working road infrastructure, which is because of collective efforts already built in terms of main net of roadways, and the attention is now paid to its service life primarily from a point of view of a climate change which is causing more frequent temperature extremes. This thesis sets its goal to perform basic tests for bitumen, especially ones dealing with low temperature properties, on types of bitumen usually used in out day to day world and asphalt mixtures made with those types of bitumen. The theoretical part talks about the basic definition of bitumen and studies performed on the similar issue. Practical part of the thesis is focused on performing the tests of bitumen and asphalt, which include but are not limited to, penetration test, softening point test, critical temperature detected by method by Fraasse and the bending beam rheometer and the test to set critical temperature of asphalt by using TSRST. At the end of the thesis the evaluation of results and its mutual correlation is performed.
7

Funkční zkoušky na směsích zkušebního úseku s asfaltovým betonem s vysokým obsahem R-materiálu / Functional tests on mixtures of the test section with asphalt concrete and high amount of RAP

Kučerová, Marcela January 2018 (has links)
The diploma thesis is focused on the testing of asphalt mixtures of asphalt concrete containing reclaimed asphalt and laying of the test section. The theoretical part deals with the use of reclaimed asphalt in hot asphalt mixtures, namely the specifics of rejuvenating agents, aging and asphalt mixture. Further more information on the functional properties of asphalt mixtures and the influence of reclaimed asphalt on them is given. The practical part describes testing of mixtures of ACO 11+ and ACO 11+ with 50% reclaimed asphalt and tests on asphalt binders. In order to compare the proposed mixtures, the low thermal properties of ČSN EN 12697-46 and the stiffness modules according to ČSN EN 12697-26. In the last part of the diploma thesis the results of the measured values were compared with each other in order to determine of asfphalt recovery. From the overall test results, it can be seen that the effect of the rejuvenating agent was positive. However, the desired degree of rejuvenation has not been achieved after production.
8

Snižování pracovních teplot při výrobě a pokládce asfaltových směsí / Reducing the operating temperature of the production and laying of asphalt mixtures

Komenda, Radek January 2013 (has links)
The subject of this thesis is the issue of reduction of the operating temperatures in the production and laying asphalt mixtures with a more specific focus on influencing the functional properties of these mixtures, especially low-temperature parameters. The thesis is notionally divided into two parts. The first part refers to the low-temperature asphalt mixtures and the second part pays the attention to asphalt mixtures with an added R-material. For production of asphalt mixtures in the first part of thesis were used five additives and for the second part were used a total of four different asphalt mixtures which differs in the participation of added R-material. Both parts are divided into a theoretical part, which discusses the existing experience, the use of these mixtures and the practical part, which analyses in detail the tested mixture ( the composition and preparation of tested specimens ) and deals with the result of laboratory test. In particular, it is a test of asphalt mixture resistance against the formation of frost cracks according to ČSN EN 12697-46 and by comparing the individual mixtures in comparison with the reference sample and among each other.
9

Asfaltové vrstvy s výztužnými sklovláknitými geomřížemi / Asphalt layers with reinforcing glass-fiber geogrids

Sachr, Jiří January 2019 (has links)
This diploma thesis deals with the use of glass fiber geogrids and geocomposites in road construction. The reinforcement elements are inserted between the wearing and binder asphalt layer. This diploma thesis summarizes the knowledge connected with reinforcing of asphalt roads using glass fiber. It examines the effect of reinforcing fiberglass elements on the resistance of asphalt layers loaded with traffic. At the same time, it deals with the application of a various amount of tack coat and subsequent behavior of the asphalt layers. In this work, laboratory tests of bond strength between layers on cores and four-point bending were performed.

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