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Electric Drive Diagnostics and Utilization in Agricultural Machinery
Čedík, Jakub ; Pexa, Martin (advisor) ; Kumhála, František (referee)
This doctoral dissertation thesis deals with rotary mowers, specifically with the issue of mulching.
In the theoretical part the reader is being familiar with the technology of mulching and its importance. Further, the individual types of mulchers and its advantages and disadvantages are described. The literary analysis of energy demands of rotary mowers is stated. Further, the parameters influencing energy demands of the mulcher are also analyzed.
The results of measurement of the energy demands of the mulcher with vertical axis of rotation are presented. The dependency of input power, specific energy consumption and fuel consumption on mass performance of the machine are created. Furthermore, the energy demands was determined, while mulcher was working continuously at the permanent grassland. The energy losses of the mulcher were also analyzed.
The effect of modification of operational and constructional parameters on the energy demands and quality of work of the mulcher wit vertical axis of rotation is studied. From the constructional parameters the shape of working tool, especially cloth angle and rake angle of the tool, and shape of the cover of the mulcher workspace is modified. From the operational parameters the cutting speed and mass performance according to conditions is modified.
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Methods of Tensile Force Measurements for Modern Soil Tillage Machines
Procházka, Petr ; Kumhála, František (advisor) ; Soukup, Josef (referee)
This Ph.D. thesis is focused on tensile forces measurement process of modern tillage machines for bigger working width. There is a limited amount of measuring devices for tensile forces higher than 100 kN.To eliminate tensile rod disadvantages (need of use of two tractors is complicated for measuring operation during the headlands turns) the
new measuring frame was developed to measure the tensile forces. To characterize the physical attributes of the soil, before the new developed measurement, the samples of unbroken soil where taken (Kopecky cylinders. The penetration resistance of soil was measured in a horizontal and vertical profile by use of penetrometer.The measuring made on specific lands proven the new developed measuring device to be able to measure the tensile force up to 200 kN
and more. The practical use of the measuring device was comparable to the measuring by a tensile rod during the measuring process.The considerable influence of the soil moisture was proven by the penetration measurements of the soil. The vertical and horizontal penetrometer measurements showed a similarity of the measuring method. The horizontal penetrometer might be a useful measuring method for a quick analysis of soil physical character considering accurate soil moisture measuring. Accurate instant soil moisture measuring and precise measurement of chisel plough working depth is a current theme for a future research.
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The comparison of different methods for soil physical properties determination
Domin, Vojtěch ; Kumhála, František (advisor) ; Mašek, Jiří (referee)
This diploma thesis is focused on comparison of the methods which are used for soil physical properties measurement . A penetrometer and Kopecky rollers were used. To assess these methods, the soil properties were evaluated on the land of joint-stock company Sloveč near Městce Králové. The first part of this thesis consists of an introduction which describes the basic information related to this issue. The second part deals with literature review where the basic physical properties of soils are discussed, such as porosity and bulk density. The aim of this diploma thesis is mentioned in the third part. It is followed by the methodology in which the different methods of measurement are described. The next chapter focuses on the analysis of measured data and its evaluation. The next part deals with the technical-economic evaluation of measurement methods. The last part brings the conclusion which summarizes all the results of the thesis. The most interesting result of this diploma thesis that penetrometric measurement is affected by soil moisture content so significantly that it can show soil compaction entirely on other areas of the land than measurements using Kopecky rollers.
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Evaluation of advanced engineering use in tropics and subtropics
Mikuláš, Dalibor ; Prikner, Patrik (advisor) ; Kumhála, František (referee)
Modern agriculture systems use largely powerful machines with respect to its operation potential. This trend extends to countries with low levels of agriculture, where it can be found part of global agricultural production. Primarily soil properties affect the use of modern agricultural technology in specific regions; however, agricultural machinery manufacturers still adapt traction properties for specific climatic conditions. The aim of this thesis was to analyze and assess the current state of agricultural machinery in specific regions of the tropics and subtropics, where agricultural systems are focused on the production of crucial crops for food and industrial use.
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Determination of the annual costs for golf course upkeep
Shapoval, Vadym ; Kumhála, František (advisor) ; Krupička, Josef (referee)
This thesis deals with the maintenance of golf courses and especially machinery needed for the maintenance of these courses. The work is divided into two main parts - theoretical and practical. At the beginning of the theoretical part of the thesis are explained basic terminologies of golf courses and an explanation of the basic concept is given. This is followed by an analysis of each operation, and a description of the machines that are used to perform these operations. At the end of the theoretical part, there are briefly mentioned the various components of the costs for the machine maintenance and an overview of useful formulas for calculation of the costs is discussed. The practical part contains an overview of data collected on individual golf courses, including general information about these golf courses. Evaluation obtaining results of the calculation is mentioned at the end of the thesis.
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Monitoring of rolling greens methods and frequency impact on green speed on selected courses
Fichtl, Lukáš ; Kumhála, František (advisor) ; Chyba, Jan (referee)
This diploma thesis is focused on monitoring of golf green rolling methods and its frequency impact on green speed on selected courses. In the first part of this thesis issues relating to golf, global history of golf and history of golf in Czech Republic are analyzed, also are described golf green construction methods here. There is also described golf green rolling and the effects of rolling. The next part presents methodology of experiments and presents the results of these experiments. The analyzed data showed that the green speed did not decrease too much during the day. The results of another experiment showed that the different types of used rollers have just a little effect on a final green speed increase. In other words, the differences in green speed increasimg, caused by using of different green rollers, cannot be detected by any golf player.
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