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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.
91

Návrh sušky na biomasu / Proposal dryers for biomass

Hrnčířová, Michaela January 2011 (has links)
This thesis deals with reducing the moisture content of biomass drying and its subsequent use as biofuel. The work is a belt drying and its integration into the system with a grate boiler. It proposes a variety of drying options for use of different drying media. In the end, an economic evaluation of the combustion system uses a belt dryer, and a system without any possibility of drying the fuel before it enters the boiler.
92

Měření emisivity vlhkých a suchých povrchů / Measuring of emissivity of wet and dry surfaces

Brzobohatý, Tomáš January 2012 (has links)
The objective of this thesis is to create summary of emissivity of wet surfaces, emissivity of rime surfaces and emissivity of dry surfaces. The next objective is to create materials for termovision measurement and find the use for this materials for practice. Theoretical part of thesis deals with a theory of ways of heat transfer (radiation mainly), description of emisivity concept, description of emisivity finding ways and the show emissivity of mesuared materials from avaible sources for working hypothesis. Emissivity of dry, wet and rime samples were measured as the experimental part of thesis. Experimental part of thesis consist of experiment description, working hypothesis, measuring instruments and measuring area description, measuring proces description and presentation of measured results. Obtained dependences are benefits for termovision measurent, energy evaluation and the thermal state microclimate simulations.
93

Analýza účinnosti mechanických sanačních metod se zaměřením na problematiku spojů vkládaných materialů / Efficiency Analysis of Mechanical Redevelopment Methods with a Focus to the Problems of Joints of Inserted Materials

Mizerová, Lenka Unknown Date (has links)
Parameters that characterizes quality internal building environment come forth these days. One of the main reasons for the choice of the topic of this thesis is to ensure the quality of the internal environment and well-being during the usage of the buildings. Prevention of the excessive wall dampness is one of the basic conditions of a healthy and quality building environment. The thesis verifies reliability and compares the efficiency of the selected damp-proof materials and its joints. The first part deals with the influences that are reasons for the dampness of the buildings, earmark of an interest area, introducing of the valid legislation focused on the building redevelopment, consideration and evaluation of the building constructions in light of the dampness. The next part of the thesis sets main and partial targets and consecutive steps leading to fulfilment of the targets. Selection of the appropriate redevelopment procedures, materials and joints of the selected materials selected for the experiment realization follows. As this area is relatively large, we selected mechanical redevelopment methods reaching the walls and three most commonly used materials and its joints within the framework of the selected methods. There are three main steps set in the thesis: preparation of the methodology and experiment realization, measurement optimization and measurement within the laboratory and on the real buildings, comparison and evaluation of the measured values. Experimental part of the thesis took place between the years 2008 - 2011. Experiment realization comprises of material acquisition, building of the test samples and application of the single redevelopment measures. The next step includes measurement on the individual samples on the fixed measuring points. Measurements are evaluated through the mathematical statistical methods. Efficiency of the particular materials are compared and evaluated.
94

Vliv hliněných omítek na tepelnou stabilitu místnosti / Effect of clay plasters application on heat storage

Koukalová, Pavla January 2017 (has links)
The aim of this master thesis is a research of effects of clay plaster application and natural ventilation on heat storage of a room. In addition to theoretical analysis of basic characteristics of clay as material used in the field of civil engineering, an experimental verification of these characteristical features is carried out as well. The thesis also studies thermal comfort of a room in terms of humidity and concentration of CO2 in dependence of natural ventilation. In the last part, numerical verification of effects of clay plaster application on heat storage is calculated using Simulace 2015 software.
95

Vliv fázové přeměny vody v zemině na průběh teplotního kmitu / Effect of soil water phase change on the soil temperature oscillation

Trlica, Ondřej January 2017 (has links)
This thesis deals with the study of soils freezing in terms of phase change of water contained in the soil strata on green roofs. The aim of this work is to verify the effect of phase transformation of water on the course of temperature oscillation. First described the basic characteristics of soils generally, and subsequently described processes occurring during phase transformation of water in the soil and has been carried out experimental verification of the effect of moisture in the soil on the course of temperature oscillation. In the overall evaluation of the work, an analysis of the effect of phase change water in soil on the course of temperature oscillation and the resulting conclusion of work.
96

Pařezová výmladnost jako základ obnovy a produkce nízkého lesa =:Stump sprouting as a basis for the regeneration and production of coppice /

Uherková, Barbora January 2019 (has links)
In 2008, a young coppice was established and studied in the south-eastern part of the Czech Republic. The main studied species Quercus petraea (Matt.) Liebl agg. and Carpinus betulus L. are typical species of Central European coppices. The aim of the dissertation thesis was to study the topic of re-sprouting, the process when the new regeneration of sprouts is created. Re-sprouting occurred after thinning carried out at the turn of the years 2014/2015. The number of live and dead new sprouts was recorded, and their heights were measured. Subsequently, the effects of the stump basal area before and after thinning, the thinning intensity, leaf area index and light conditions (gap fraction, openness, direct, indirect and total site factor) were studied on the newly established generation of sprouts. Another aim of the dissertation thesis was to find out the effect of thinning on the growth of the coppice in the current changing climate conditions. For three growing seasons (2015 –2017) after the thinning, the growth (diameter and height increments) and soil water content were observed. To study the effect of climatic conditions, a throughfall reduction was simulated by using drainage channels. Similar system of drainage channels was used in Spain, France and other countries. To address the topic of soil degradation, the impact of throughfall reduction and thinning on soil CO2 efflux was investigated. Comparison between subplots with and without thinning, subplots with and without throughfall reduction and coppice with false high forest (control area to the research area of coppice forest) were carried out. As far as the re-sprouting is concerned, the stump basal area before thinning and the thinning intensity statistically significantly influenced the number and height of the new sprouts. Among all factors of light condition, only the indirect site factor was statistically significant. Therefore, the thinning affected soil moisture and the amount of light in the coppice. In the first year after the thinning, the diameter increments of sessile oak and European hornbeam were positively influenced by thinning. In the following two growing seasons, thinning did not significantly influence the diameter increment. However, the height increment of both trees during the whole study period has not been positively affected by thinning. On the other hand, thinning significantly affected the soil moisture. During the three-year study period, soil moisture was higher on thinned plots. This finding is in coincidence with research experiments carried out in southern Europe. The second studied factor, which was the throughfall reduction, did not influence neither the diameter increment, nor the height increment and nor the soil moisture in both species for the entire period. Thinning did not affect soil CO2 efflux rates, whereas the throughfall reduction did. Coppice reached almost the same soil CO2 efflux rates as the false high forest. In conclusion, thinning in coppice leads to an increase of available soil water. The water availability will be very actual issue at lower altitudes – here the tree species are sensitive to high air temperatures and drought stress. It should be noted that the younger developmental stages of the forest stands show increased sensitivity to water deficit due to drought. Thanks to sprouting ability, coppicing can therefore be appropriate management in some deciduous stands at lower altitudes under changing climate conditions.
97

Vodní režim rekultivovaných a nerekultivovaných výsypek / Water regime of reclaimed and nonreclaimed heaps

Cejpek, Jiří January 2011 (has links)
Summary: Great Podkrusnohorska spoil heaps in the Sokolov region in Western Bohemia is the largest spoil heaps in the Czech Republic, which was pour million tonnes of overburden soil surface mining of brown coal. The thesis is setting on the basic characteristics of the water regime and water balance of spoil heap soil and thus follows a series of previous works dealing with the comparative development of the reclaimed and unreclaimed area. The areas are long-term monitoring of soil moisture using a dielectric soil moisture meter total water regime was monitored by subsurface with gravitation lyzimeter, runoff and throughfall rainfall. Older unreclaimed plots as well as reclaimed plots have higher porosity, water field capacity and moistre than young sites, however there are limited by water deficiency in similatr way as young sites due to increase in wilting point. Keywords: Spoil heaps, Recultivation, Soil humidity, Water supply, Water balance
98

Hustotní profil a jeho vliv na vlastnosti třískových desek

Matyáš, Michal January 2017 (has links)
The goal of this thesis is to determine properties of manufactured particleboards with different percent content of recycled wood. The objective was to determine density values, thickness swelling, moisture content, internal bonding, bending properties and vertical density profile of particleboards. The research question was to report the effect of different percent content of recycled wood on final properties of particleboard. The own method was established and various particleboards produced. The properties of materials were tested according to EN standards and by descriptive statistics, analysis of variance (ANOVA) and linear regression evaluated. In summary in research it was observed that percent content of recycled wood has little impact on final properties of particleboard, although there were several factors which may have affected these results. These factors are described in this thesis.
99

Evaluation of water use efficiency of short rotation poplar coppice at Bohemian-moravian highlands

Hlaváčová, Marcela January 2014 (has links)
The diploma thesis provides basic characteristics of short rotation coppice plantations, then the most significant short rotation coppice species cultivated in the Czech Republic are described. The detailed description of particular Populus L. clone J-105 grown at the plantation of the Test Station Domanínek Ltd. follows. Afterwards, key determinants of short rotation coppice yield are presented in the text. The last theoretical part of the thesis deals with water use efficiency (WUE) with emphasis on the method used at the experimental plantation in Domanínek. The methods of sap flow measurements and biomass determinations are described for this purpose. The main aim of the practical part of the thesis is to determine WUE of 16 measured trees where sap flow measuring systems were installed. These trees are divided into 3 cohorts according to diameters at breast height (DBH) at the beginning of the growing season 2013. The additional measurements were carried out: phenological imaging, soil moisture measurements, LAI measurements and sapwood area determination. The statistical analysis of WUE did not show any statistically significant differences between values of WUE for individual cohorts. Only in May, the statistically significant difference between cohort 1 (trees with the thickest stems) and cohort 3 (trees with the lowest values of DBH) appeared.
100

Analýza vlivu vybraných faktorů na xylogenezi a floémogenezi smrku ztepilého (Picea abies (L.) Karst.)

Vichrová, Gabriela January 2014 (has links)
No description available.

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