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The aim of this study was to determine the effect of density and kinship on the rate of metamorphosis of the selected species of frogs. The work was made in Rana temporaria, common frog. Tadpoles of this species have been bred at different densities kindred subjects. The regular weekly intervals were timed tadpoles until metamorphosis. It has been shown that tadpoles reared individually developed much faster and metamorphosed at larger sizes. Contrast, tadpoles raised in unrelated groups developed much more slowly than in the group composed of related individuals.

The aim of my diploma thesis was to evaluate four densities of growth by chosen varieties of potatoes. The thesis deals with the experiment on 4 different varieties of potatoes. I have chosen the standard technology of growing ware potatoes. The selected densities of growth were 35 000, 40 000, 45 000 and 50 000 young plants ha-1. Each variant was repeated four times. I have evaluated the yield of bulbs, the share and yield of ware bulbs, the average number of bulbs for one plant, the weight of bulbs for one plant, the average weight of a bulb and the average weight of ware bulbs. The research was done on a private farm like the field experiment. The farm is located in potato-growing area in Vysočina Region, 490 metres above the sea level. Potatoes are grown approximately over 7 hectares on the farm. The experiment started in 2010. The potato planter MARS 42 was used for the planting. The distance between drills was 0,75 metre. Parcels consisted of 4 drills, each drill equals one repetition, each parcel equals one density of growth. On purchase of samples was realized the kickoff of 10 plants from each repetition. What followed was division of bulbs according to their size in each sample. They were divided into bulbs smaller than 40 millimetres and bigger. After that the samples were weighed and bulbs were counted. The number of bulbs and the weight of bulbs are very important for subtotal. It was established the variety Mirage made the best results when the density was 45 000 plants ha-1. The variety Agria had two suitable densities of growth, namely 40 000 and 45 000 plants ha-1. There was no considerable difference between them. In contrast with previous, the varieties Victoria and Marabel made the best result when the density was 35 000 plants ha-1. I have realized the density 50 000 plants ha-1 is explicitly unsuitable for all varieties. This density of growth is loss-making especially because of lowering of all assessed indexes. Another disadvantage is higher costs (more bulbs are required) and then there is also bigger risk of diseases and pests.

The decomposition dynamics of deadwood was investigated using robust 40-years-long temporal dataset and physical properties of decaying logs in alluvial, fir-beech and fir-spruce-beech natural forests. While the downed logs of most alluvial tree species are decomposed in 23-42 years depending on DBH, the large-sized logs of Quercus robur had a residence time 73 years. Deadwood of Fagus sylvatica decomposed completely in 30-53 years and Abies alba in 53-95 years depending on the macroclimatic conditions and DBH. Deadwood of Picea abies had a decomposition time 58-81 years on the site of a mountain mixed forest. In addition, the effect of the mortality mode and position of logs on the decomposition time was confirmed. Evaluation of deadwood density on sampled logs showed that the remaining mass (decay rate) varies greatly between the logs with the same values of time since death. This confirmed the need for robust data for observations about deadwood decomposition.

In one year (2017) small plotting field experiment with sow corn was compared influence of density of sowing on gain of grains between a few chosen varieties of crossbred grainy corn. For the experiment there were used 6 varieties of grainy corn, bred by Limagrain company. Concretely crossbreds LG 30.315, LG 30.369, LG 30.215, LG 32.58, LZM 266/52 and LG 31.276. All of the varieties were sown in 5 different densities (50 000, 65 000, 80 000, 95 000 and 110 000 individuals/ha) in 3 repetitions. After ingathering, by all of the varieties, were compared the gain of the grains in 14 % dampness, dampness while ingathering and weight of thousand grains while dampness 14 %. The biggest gain was achieved with varieties LG 31.276 and LG 30.369, however at the same time they had the highest dampness. The biggest weight of thousands of seeds was achieved by density of sowing 50 000 individuals/ha (approximatelly 294,58 g). Generally we can say, that higher desity of sowing has a negative influence on weight of thousands of grains. Field experi-ment corroborated, that for achieving higher gain is important density of sowing, according to chosen crossbred. Highest gains were achieved with density of sowing 80 000 and 95 000 individuals/ha.

The diploma thesis deals with the problematics of engine oils degradation in a garden machinery. In the theoretical part, there is a description of the basic functions and properties of engine oils, their production, composition and also used standard classifications. The practical part is devoted to evaluation of the degradation of five selected engine oils. There are described the oils, the selected garden machinery (five machines with a four-stroke spark-ignition engine) and also the sampling methodology and measuring devices. Two samples of oil were taken from each machine – a partially used and a used engine oil, which were compared with a new oil of the same specification and designation. For all samples, their dynamic viscosity (at 40 °C), density and amount of selected metal wear particles were measured. In the final chapter, the measured parameters are processed into a tables and graphs, and the results are discussed.

The aim of this thesis was determination of basic density of silver birch (Betula pendula Roth.), from segments taken from the breast height, in relation with the stand structure. The research was conducted in area Nízký Jeseník and Slavkov. The segments were taken by Pressler auger in three stands with different age per the area. The average basic density of the silver birch is 491,1 kg∙m-3 (Velká Polom) and 504,2 kg∙m-3 (Slavkov). The positive correlation was found out between the basic density and the age. The dependency between basic density with height and diameter at breast height is very low. The other matter was the determination of variability of basic density along the stem height– the values increases with the height of the tree. The analysis of possible relation between the basic density and the average tree-rings width showed that the dependency is low.

This Master's thesis focuses on the problematics of the diesel engine oil in the combine harvesters degradation. The first part focuses on the manufacturing process of the en-gine oils, on their structure, on the description of their properties and on their division into individual classifications. Types of the lubrication systems and the diagnostics of the engine oils are described next. Seven samples of oil were monitored, three of them were samples of used engine oil from the combine harvesters Claas, where the engine oil with viscosity grade 10W-40 was used. Next two samples were from used oil from the combine harvesters Case IH, where was the engine oil with viscosity grade 15W-40. Two samples of new oil of each kind were taken for the comparison of the engine oil degradation. Their physical and mechanical properties were compared afterwards. The results obtained are interpreted both numerically and graphically. In the conclusion, the evaluation and the results obtained are summarized.

This diploma thesis deals with rheological properties of cream in this theoretical part. The first part describes the composition of milk as a basic product in the production of cream, and the definition of cream according to legislation and its composition. Another part of the thesis is focused on the production of cream and its distribution by kind. In the next chapter, attention is paid to the rheological properties of food, esspecially viscosity and density. The practical part is focused on the measurement of rheological properties of 10 whipping cream samples available on market. The fat proportion of the samples ranged between 30 - 33 %. For all of these samples, viscosiy and density were measured. For chosen samples was also determined the dependency of shear stress to shear rate. This dependence, using Ostwald-de Waele model, determines what type of fluid is involved. Another observed parameter was the dependency of the dynamic viscosity on the shear rate and the relation of this viscosity to the temperature changes. All samples were subjected to analytical determination of cream (dry matter, fat, titration acidity, active acidity, electrical conductivity). From the analysis of the fat proportion proportion, we are able to compare our measured data to the projected data declared by producers.

In this thesis we consider an open question of Feige that asks whether there always exists a constantly Lipschitz bijection of an n2 -point subset of Z2 onto a regular grid [n] × [n] for every n ∈ N. We relate this question to an already resolved problem of the existence of a bounded positive measurable density in R2 that is not the Jacobian of any bilipschitz map. This problem was resolved by Burago and Kleiner [1], and independently, by McMullen [12]. We present the work of Burago and Kleiner, analyze its relation to Feige's problem and sug- gest a continuous formulation of Feige's question in a special case. Then we present the Burago-Kleiner density, make several observation about the properties of this density, and after that we construct a density that is everywhere nonrealizable as the Jacobian of a bilipschitz map. Subsequently, we discuss our continuous variant of Feige's question, provide several observation concerning it, and finally, we try to use the everywhere nonrealizable density constructed before to answer our continuous variant of Feige's question. However, this last task still remains incomplete. 1