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Comparison of production and conditions of use of liquid biofuels in different countries
Semerák, Adam ; Pecen, Josef (advisor) ; Krepl, Vladimír (referee)
Biofuels production has experienced rapid growth in recent years. Many countries initiated legislative measures to promote their development, production and use in the transport sector. However, there are also growing concerns about the economic, environmental and social sustainability of biofuels, as well as their ability to truly meet the expectations of energy security.
This paper attempted to point out the complexity and diversity of the production and use of liquid biofuels in the transport sector while using available information resources. More specifically, bioethanol and biodiesel which are most commonly used biofuels. Furthermore, he also tried to point out the diversity of characteristics and impacts in production and use of liquid biofuels, as well as the importance of consideration of the specific local conditions. That was examined from four perspectives of sustainability: technological, economical, socioinstitutional, and environmental. To illustrate the diversity and interdependence of the impacts of this whole issue two countries with very different human development indexes were selected. The Malaysia and India.
At the basis of this paper the author concluded that for successful and sustainable production of liquid biofuels there must be taken into account all the factors examined equally. He also emphasized the importance of further research of this renewable energy source in terms of ensuring future energy security.
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Scattering of Sun Radiation on Microparticles in a Closed Environment of Water Bath
Jelínek, Marek ; Pecen, Josef (advisor) ; Zeman, Josef (referee)
This thesis deals with an alternative technology used to illuminate spaces without access to daylight. Technology uses primarily scattering and also reflection and refraction of sunlight in the optical environment of the PET bottles with water and microparticles. The base of technology consists of a plastic bottle filled with water with microparticles and positioned so that it vertically penetrates the roof interior. The effect of scattering of sunlight in the bottle is amplified by using a suitable material of the microparticles.
Review of literature deals with areas that the technology is primarily designed for and the current state of expansion. The principle of technology and factors affecting its efficiency are explained.
The aim of the experiment was limited testing and selection of suitable material of microparticles and their concentration for the possibility of practical use within the technology described. Several measurements were performed of the intensity ratio of incident and scattered light using selected materials of microparticles of various concentrations. Based on the obtained values and their comparison a solution containing 0.5 g of limestone into 1.5 l of water was selected as the most suitable optical environment for the solution.
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Influence of texture of briquettes from biomass to their mechanical properties
Černá, Iva ; Pecen, Josef (advisor) ; Jan, Jan (referee)
With the rising amount of AD technology utilizers, the issue how to storage, such liquid
material, which digestate is. In recent time, there are some other ways to utilize it, except
fertilizing with liquor, liquid part of digestate. Digestate can be dried and pressed into
briquette or pelleted form. In briquette form is important to understand relations between
properties of individual components because one property can influence another one, which
constituting texture of the material and its reprocessing into the final form of the product.
Thus this study was conducted, to find and/or quantify the relation between the texture of
biomass briquettes and their durability and strength of shape during manipulation, storage
and use. Basic hypothesis of this work is based on open presumption that briquette texture is
dependent on many parameters. Some of those parameters were tested. Namely, composition
of matter, physical properties of digestate briquettes, durability and hardness, size analysis
and other. Digestate has approved as good material for compression with high content of
nutrients. The rate of abrasion varied 7-12% at the beginning decreasing to 3-5%. Shore
testing showed results predicating relation between particle size and hardness. Sieve and
image analysis then showed range of particles ranging size 0.01 mm from 99.5% and 10 mm
from 99.7%, most of them with needle-like shapes. This study suggested the method that
allows analysing particle size distribution in sample and describes other briquette properties,
which can be useful for next research and commercial purposes.
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Suitable Methods of Determination and Varification Ammonia and Selected Greenhouse Gasses Detection
Zabloudilová, Petra ; Pecen, Josef (advisor) ; Jan, Jan (referee)
The dissertation deals with methods of detection gases from agriculture, especially ammonia. To understand and control of ammonia and others gases (i.g. methane) depends on sampling and measurement techniques that includes devices, instruments and procedures. In the theoretical part are listed the basic characteristics of ammonia and selected greenhouse gases and its environmental effects, sources of emissions and characteristics of chosen gas sensors (especially semiconductor sensors). In the experimental part of the work were tested conditions of chosen types of sensors (especially semiconductor sensors) mentioned above in the laboratory, according to the change of relative humidity and concentration detection gas especially. The chosen sensors were verified for measuring in the operational conditions (in the barns). Finally, the advantages and disadvantages of tested sensors are discussed (with regard to use these sensors in operational conditions).
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Optimization of microclimate parameters in dairy farms, while reducing the energy consumption of selected technological systems
Češpiva, Miroslav ; Pecen, Josef (advisor) ; Ján, Ján (referee)
Thesis is focused on the measurement and evaluation of microclimate parameters in barns for dairy farming and the determination of the energy consumptions of selected technologies in these barns. The aim of this work was to design and eventually to implement adjustments in order to improve the parameters of cowshed microclimate and reducing the energy consumption of selected technologies in depends on results of the measurements. Three structurally different cowsheds with different slurry clearing technologies were selected for monitoring. I focused on the measurement of temperature and relative humidity in relation to temperature- humidity index and its impact on heat stress on dairy cows. I measured airflow in the cowsheds and I determinate concentrations and emissions of ammonia and methane in the cowsheds in different seasons. I monitored light intensity in the cowsheds and I determined the dependence of building solutions on the use of outdoor light to illuminate the interior of the barns. The energy consumption of the lighting system depending on the season and the consumption of additional fans on the air temperature were studied.
On the bases of results of the experimental part I designed and implemented lighting system, controlled by light intensity in a cowshed and energy-saving ventilation in the cowshed - type K105. I suggested a system of continuously monitoring of climatic parameters in the cowshed with immediate calculation of temperature- humidity index.
Measurements have shown the dependence of gases concentrations on the way of slurry clearing technologies. The building solutions of cowsheds and type of ventilation proved a significant influence on the temperature- humidity index during the summer.
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