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Car cabin passive cooling system performance study
Viščor, Petr ; Hejčík, Jiří (referee) ; Fišer, Jan (advisor)
The work is focused on issue of passive cooling in a cabin of a car. The basic principles and mechanisms of heat transfer are described in the theoretical part and the quality of cabin environment in terms of thermal comfort and air quality is discussed as well. Next part of the work describing the principles of ventilation and air conditioning of cabins and possible methods of passive cooling are discussed. Passive cooling means decrease of temperature of cars interior, without need of energy supply from car battery, or fuel. The last part of the work includes numerical simulation of selected methods of passive cooling using the THESEUS-FE 3.0 software. Simulations were performed on model of Volkswagen Polo car and primarily were focused on testing of functionality of various methods of passive cooling.
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Comparison of chemical composition of throughfall and deposited precipitation
Chaloupecký, Pavel ; Špičková, Jitka ; Fišák, Jaroslav ; Skřivan, Petr
Since June 2004 throughfall samples in beech and spruce vegetation have been taken at the observatory Milesovka. Ever since 1998 fog water samples have been taken there as well. In this paper are compared the concentrations of main ions and trace elements in throughfall and in deposited precipitation. The concentrations of main ions and trace elements in throughfal are primarily affected by the volume of samples. The highest concentrations of monitored sustances in throughfall were recorded in September and in October when the lowest rainfall totals were measured. The concentrations of monitored sustances were in throughfall mostly higher in spruce vegetation in comparison with beech vegetation. It is probably due to the thicker treetop in spruce vegetation on Milesovka observatory. Due to the thicker treetop a smaller volume of throughfall is let fall and the substances from ambient air are captured more effectively in comparison with beech vegetation. In the case of main ions the lowest concentrations were measured in fog water samples. For trace elements wasn´t data. From comparison with reference locality Lesni potok is obvious that concentrations of monitored sustances in throughfall on Milesovka exceed sharply concentrations in locality Lesni potok. This difference is considerably higher by spruce vegetation in comparison to beech vegetation which indicate that it is necessary take not only local air quality into account but also type of vegetation and thick of treetop which can very significantly contribute to the chemical composition of throughfall.
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Effect of an exhaust opening location on air quality in an apartment
Charvát, Tomáš ; Forman, Matěj (referee) ; Krejčí, Vladimír (advisor)
This thesis deals with the influence of the location of exhaust outlets on the air quality. The study examines the performance of the hybrid ventilation system installed in an experimental house. The central point of this work is a numerical model of a bedroom with heat and carbon dioxide sources. The temperature, speed and concentration fields have been solved for, from which further quantities of thermal comfort PMV, PPD and DR were evaluated. Finally, the impact of changes in the quality of the microclimate using these quantities and in the energy efficiency ventilation is assessed.
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Optimization of internal ambient air quality in libraries and archives aimed at reduction of degradation of library and archival materials
Součková, Magda ; Vávrová, Petra ; Novotný, Jan, ; Dřevíkovská, Jana ; Paulusová, Hana ; Bartl, Benjamin ; Bartlová, Lenka ; Bacílková, Bronislava, ; Straka, Roman ; Ďurovič, Michal, ; Mašková, Ludmila ; Smolík, Jiří
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An evaluation of the effectiveness of investments in energy savings
Ondráček, Jan ; Klímová, Lenka (referee) ; Vaňková, Lucie (advisor)
Investments in energy saving of buildings is associated with a reduction in the operating costs, but it is also an effort to improve the quality of the environment. The main impulse are constantly rising energy prices and deteriorating air quality. The diploma thesis deals with the return on investment in thermal insulation of residential houses. The theoretical part describes the different definitions from the field of investments, pricing and energy modifications. In the practical part are considered two apartment buildings, the first insulated, non-insulated second. The next step is quantifying of the investment cost of such insulation designed with the calculation of payback period, net present value and internal rate of return. At the end of the work is the evaluation of the effectiveness of investments.
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The Effect of Oregano Essential Oil on Microbial Load, Drying Kinetics and Sensory Atributes of Dried Meat
Hernandez Hernandez, Helga Johana ; Banout, Jan (advisor) ; František, František (referee)
Microbial load can be controlled using either synthetic or natural preservatives. Particular interest has been focused on the potential application of plant essential oils as safer additives for meat. However, there is no published research on the use of essential oils during the meat drying process. This study was focused on enhancing the meat drying process. At first a value-added dried meat product by using oregano essential oil (OEO) to inhibit the growth of bacteria, and the sensorial response from assessors is presented. It was found that the application of the OEO in meat is effective in inhibiting Salmonella enteritidis and Escherichia coli. After 6 hours of drying at 55°C, 2 ml (0.038 ml l-1 air) and 1.5 ml (0.028 ml l-1 air) of OEO were considered the minimal inhibitory concentrations (MICs) against S. enteritidis and E. coli, respectively. Samples treated with 0.75 ml of OEO were more attractive for consumption compared with the control; at a higher concentration of OEO, the sensory quality of the food was affected.
Next, the effect of modified blanching treatments on the drying behaviour of beef meat was evaluated by determining moisture ratio versus time curves and the influence on sensory quality of the resulted product. The 3 treatments under investigation were (1) oil treatment (2) steam blanching and (3) hot air blanching with 3 doses of oregano essential oil (1) 1.5 ml (2) 3 ml and (3) 6 ml. Each treatment had an effect on the drying time of the beef samples, however, the dose of oregano essential oil applied did not affect the drying process. The results showed that steam blanching was very effective reducing the drying time. Meanwhile, 1.5 ml and 3 ml hot air blanching samples and 1.5 ml oil treatment samples were judged as better from sensory point of view and the respondents considered that adding oregano essential oil enriched the pleasantness of the smell.
In conclusion, a value-added dried meat product obtained by using oregano essential oil to enhance food safety received an acceptable sensorial response from consumers. Additionally, each modified blanching treatment tested influences the drying kinetics process, but the dose of oregano applied did not affect the drying process. In this sense, hot air blanching and oil treatment with the lowest dose had an acceptable sensorial response from consumers.
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The effect of housing system on egg shell quality and egg internal quality
Vlčková, Jana ; Tůmová, Eva (advisor) ; Skřivanová, Eva (referee)
In the study 3 experiments were carried out. The objective of the first experiment was to evaluate performance of laying hens, quality of air in poultry house, and microbial contamination of the eggshell in laying hens kept under blue, green, red, and yellow light colour in enriched cages. The laying performance characteristics (hen-day egg production, mortality, and egg weight) were not affected by light colour. Similarly, microbial contamination of the air was not significantly different related to the light colour. There were significant interactions in eggshell contamination between cage floor and light colour in Escherichia coli and Enterococcus. The highest number of Escherichia coli was detected in eggs from hens housed in the middle floor given yellow light and the lowest values on the upper floor also under yellow light colour. Similar results were observed in Enterococcus. The results of our study indicate that the light colour has a minor effect on microbial contamination but the significant influence was in the floor position. The highest microbial egg contamination was found on eggs from the middle floor.
In the second experiment, the effect of housing system (conventional cage, litter, aviary) and feed calcium content (3,0 and 3,5%) on laying performance characteristics, technological quality of eggs, microbial contamination of the eggshell and egg content during storage was evaluated. The significant interaction between housing system and feed calcium content was found in egg weight, eggshell strength, eggshell percentage, eggshell weight, Haugh units and albumen index. The housing system affected egg production, feed intake, egg weight and some characteristics of eggshell quality. From characteristics of eggshell quality the feed calcium content affected only eggshell strength and eggshell percentage. The significant interaction between housing system and storage time was found in contamination of eggshell by total number of microorganisms. The housing system affected also contamination of the eggshell where higher number of Escherichia coli and total number of microorganisms were in eggs from litter. Higher penetration of all monitored species of microorganisms on the eggshell membranes was 2nd and 7th day of storage in the group with 3.5% of calcium in the feed mixture in eggs from the litter. This could be associated with lower quality of eggshell in this type of housing.
In the experiment 3, the effect of different housing system (enriched cage, free range) on technological quality of eggs, microbial contamination of the eggshell, egg content and concentration of protein in albumen during storage was observed. The housing system affected all characteristics of eggshell quality with higher values in cage system. Higher number of pores in eggshell was found in free range. The important relationship between housing system and storage time was indicated in Haugh unit, albumen index, pH albumen and yolk index. The values for characteristics quality of albumen and yolk were better in eggs from cages. Their quality during storage decreased faster in alternative housing systems. There was detected interaction between housing system and storage time also in Escherichia coli, Enterococcus and total number of microorganisms. The highest microbial contamination in fresh eggs was found in free range. The number of microorganisms with storage time significantly decreased faster in eggs from cage system. The penetration of Escherichia coli and total number of microorganisms in albumen was lower in eggs from cage compared to free range. The significant effect of housing system was found in concentration of lysozyme in albumen with higher values in egg from free range. It is obvious that a better quality of the eggs is in the cage housing system. The eggs from this type of housing also remain during storage for longer time in better quality compared with alternative housing systems.
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Air Quality in Different Types of Archives
Mašková, Ludmila ; Smolík, Jiří ; Ondráček, Jakub
Particulate matter (PM) and gaseous pollutants in libraries and archives can be harmful for materials stored there. The study includes indoor/outdoor monitoring of air quality in 4 archives, which representing different outdoor environments: Zlatá Koruna (rural), Třeboň (small city), Teplice (industrial area), and Prague (large city with traffic). The aim of this study is to investigate concentrations and sources of airborne PM and gaseous pollutants in the indoor environment of the archives, and to establish the relationship between the indoor and outdoor environment. The results indicated outdoor air as the most probable source of particles in the indoor environment of naturally ventilated archives at Zlatá Koruna, Třeboň and Teplice. The concentrations in the indoor environment in Prague are relatively constant and low, because the archive is equipped with a sophisticated filtration systém.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22013101814590 - PDF
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Avenue foundation in extreme conditions special respect to soil quality
Šimek, P. ; Šimek, Miloslav
Quality of soil environment is an important factor which substantially influences growth of plants. Present paper deals on general features and main parts of soils. The importance of soil air content and composition of soil air together with main principles of movement of gases in soil are described. Soil aeration status, namely low oxygen concentration, both low and high carbon dioxide concentrations and higher ethylene concentrations directly influence plants. Changes in amount and composition of soil air impact a number of soil physical and chemical properties, and by this mechanism also influence plant growth and behaviour.
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