• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 227
  • 19
  • Tagged with
  • 246
  • 162
  • 125
  • 55
  • 55
  • 50
  • 44
  • 40
  • 39
  • 38
  • 34
  • 34
  • 34
  • 34
  • 33
  • 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.
11

Databáze tepelných parametrů oblečení pro systém iHVAC / Drivers clothing thermal resistance database for iHVAC system

Hrubanová, Kristýna January 2017 (has links)
This diploma thesis is focused on measurement of thermal properties of clothes by thermal manikin and on application of results for prediction of thermal comfort in system iHVAC. First part of thesis is dedicated to research with relation to this topic and to definitions of main computational equations necessary for experimental measurement. The choise of method for measurement based on available standards is an important part of this thesis. The main focus of thesis lies on measuring 5 combinations of clothes at different calibration temperatures and same temperature of manikin surface. Then data are examined and also the analysis of uncertaities and repeatability is maked. According to assupmtion , the independence of value of heat transfer coefficient to ambient temperature is comfirmed and calculated heat resistance of every single clothes is compared to existing wardrobe for system iHVAC. The outcome of this thesis is specificied and completed virtual wardrobe which serves to prediction of thermal comfort in car.
12

Vliv vybraných faktorů na reprodukční vlastnosti dojnic / Effect of selected factors on reproductive characteristics of dairy cows

Šťásková, Michaela January 2016 (has links)
The aim of the thesis was to evaluate the effect of selected factors on the reproductive characteristics of Montbeliard dairy cows. Hypothesis said that high milk production, poor health and high air temperatures have a negative effect on reproductive indicators of cows. In the literature review, there were summarized knowledge about the factors affecting fertility, reproductive indicators and a description of the breed. Observation was carried out on the farm Osičky, which is one of the centers of the company Agrodružstvo Lhota pod Libčany. To assess the influence of milk yield and health were monitored all standard lactations of dairy cows, which were completed in the period from 1. 1. 2014 to 31. 12. 2015. This gave rise to a set of 632 lactations. To evaluate the milk production was data set divided by the number of lactation, quarter of calving and the rate of milk production into three groups. As a disease with an expected negative impact on fertility, mastitis was selected. Besides air temperature, the relative humidity was assessed too. Indicators such as days open, days from calving to calving and services per conception were evaluated. In order to assess the impact of climate change on fertility data file was divided into 3 groups of air temperature, by quarter, according to the category of cows and by calendar year. Services per conception, pregnancy after the first insemination and pregnancy after all insemination, were assessed. Data could be obtained only from a whole herd of cows and heifers. For statistical evaluation has been used SAS 9.3 software (SAS / STAT 9.3, 2011). Achieved an average length of days open was 98.07 days, days from calving to calving 380.62 days, services per conception was 1.94, pregnancy after the first insemination in heifers 54.28% and 48.43% in cows, yield per lactation was 8 407, 98 kg of milk with fat contents of 3.65 % and a protein contents of 3.53 %. Mastitis occurred only in 17.72 % of cases. The average monthly air temperature during the year 2014 ranged from 1.3 ° C to 21.2 ° C, in 2015 it was 1.5 ° C - 23.2 ° C. From the results of the regression analysis, it was found that the milk production per lactation had a statistically significant effect on the length of the days open (r = 0.214; P <0.001), services per conception (r = 0.296; P <0.001) and days from calving to calving (r = 0.147; P < 0.01). Therefore we can talk about the significant influence of milk production per lactation. With the increasing amount of milk kg days open and days from calving to calving extended and services per conception also grew. Analysis of variance confirmed the effect of the amount of milk yield per lactation on days from calving to calving (P <0.05), days open (P <0.001) and services per conception (P <0.001). Furthermore, quarter of calving had a significant effect (P <0.05) on services per conception and days open and the effect of category on pregnancy after all insemination (P <0.01) and services per conception has been demonstrated (P <0.05). Heifers showed demonstrably better results of assessed reproductive characteristics compared to cows. There was no effect of the incidence of mastitis on days open, days from calving to calving and services per conception proven (P> 0.05). Effect of air temperature on services per conception, pregnancy after the first insemination and pregnancy after all insemination, was not statistically proven (P > 0.05). Furthermore it has been approved many correlations between different parameters at the levels of significance (P < 0.001, P < 0.05). The hypothesis was confirmed only for the negative impact of high milk production, but the impact of poor health and high air temperatures on reproduction was not approved. The results indicate a healthy herd in terms of mastitis, good management of breeding, which minimizes heat stress and which is of relatively high milk yield and proven negative impact of high milk production to reproduction, achieved a good level of reproduction.
13

Kontrolní tepelný výpočet teplovodního žárotrubného kotle / Rating thermal calculation of fire tube water heater

Polášek, Kryštof January 2020 (has links)
This diploma thesis deals with thermal calculations of fire tube water heater. The first part of the thesis describes different classifications of boilers and water heaters and provides a basic overview for different types of commonly used boilers. The next part describes thermal calculation model created in Maple software, used formulas and algorithm of the model. Subsequently, the model is applied to the experimental water heater in the form of computational rating. In the last part of the thesis the model is applied to the existing operated industrial water heater to evaluate predictive ability of the calculation model by comparing the essential operating parameters obtained from the calculation with real data measured on the water heater.
14

Přepočet kotle při změně jmenovitých parametrů / Recalculation boiler at change of nominal parametrs

Haška, Miroslav January 2009 (has links)
This thesis concerns with recalculation of steam boiler. Arrangement for reaching of new steam boiler parameters and temperature of combustion gases was suggested at first. Then it was verified with thermal calculation, all necessities included.
15

Plynofikace uhelného kotle 210 t/h; 13,63 MPa; 540 °C / Gasification of coal boiler 210 t/h; 13,63 MPa; 540 °C

Zajíc, Josef January 2013 (has links)
This thesis aims to gas installation of the coal boiler and its thermal recount. In the first part, there is implemented calculation of the combusting chamber. After that follows the recalculation of heat exchange surfaces and proposal tube air heater, which will replace the existing air heater Ljungström. The emphasis is placed on the preservation of the exsiting steam parametrs and keeps emission limit of NOx.
16

Plynofikace olejového kotle v cukrovaru 65 t/h, 3,8 MPa, 450 °C / Oil boilers gasification in sugar refinery 65 t/h, 3,8 MPa, 450 °C

Štukavec, Karel January 2015 (has links)
This masters thesis deals with the gasification of current oil boiler. The first part of the thesis describes the existing boiler. The next part follows gasification with respect for comply with the limits of NOX and recalculation of boiler for operation with the natural gas.
17

Analýza působení mikroklimatu ve stáji na produkci, reprodukci a chování dojnic holštýnského skotu ve vybraném chovu

Zavadilová, Kristýna January 2019 (has links)
The aim of the diploma thesis was to elaborate a literary review on the topic: Analysis of microclimate effect in stable on production, reproduction and behaviour of the dairy cows of the Holstein cattle at the selected breeding. The practical part took part in ZD Hříšice, where in 2018 yearly measurements of temperatures and relative air humidity were performed using the Onset Hobo sensor. The AfiFarm system recorded daily milk yields from 355 Holstein dairy cows; performance control data were used as well. February was the coldest month with an average temperature of 5.42 °C. August was the warmest month with an average temperature 21.35 °C, simultaneously the lowest average relative humidity of 59.85 % was measured. In the production group of high-yielding dairy cows, which achieved an average milk yield of 35.6 kg, the average daily milk yield decreased by 3 kg in August. For a group of less production with an average daily production of 23 kg, production decreased by 2.3 kg. In August, the insemination index was 5.1 for cows and 2.4 for heifers. The results obtained from pedometers of dairy cows recorded the highest physical activity in July, it can therefore be assumed that they were lying less.
18

Vliv režimu práce zážehového motoru na jeho tepelnou bilanci

Studený, Petr January 2017 (has links)
The diploma thesis presents a topic The Influence of the Mode of Work of a Petrol Engine on its Heat Balance. The thesis is divided into two parts. The first one is focused on the characteristics of combustion engines and on individual components of a spark-ignition engine, which are closely related to a measurement of the heat balance. Second part of the presented thesis describes methodology of the heat balance measurement on a spark-ignition engine at the motor testing institute of Department of Technology and Automobile Transport of Mendel University in Brno. It is primarily focused on change of the individual heat flow components during different loading modes and graphic representation of them.
19

Regenerace tepla a vody při sušení papíru / Regeneration of heat and water for paper drying process

Milko, Michal January 2018 (has links)
Diploma thesis titled Regeneration of heat and water for paper drying process analyzes use of waste hot air ventilated from drying section of paper mill. Moreover is described detailed design process of recuperation heat exchanger, which should be part of regeneration loop of paper mill. Designed heat exchanger is plate-fin crossflow heat exchanger. For deasign is used – NTU method.
20

Výměník tepla pro záchranný habitat / Heat exchanger for rescue habitat

Bouma, Adam January 2013 (has links)
This thesis deals with the specific issues of designing a suitable type of heat exchanger for ventilation in a rescue habitat. The paper presents an overview of the most common types of heat exchangers and characterizes basic heat transfer mechanisms (radiation, convection). Based on the above and other knowledge, a thermal-hydraulic calculation model suitable for a regenerative heat exchanger type is compiled and the necessary calculations are performed. The thesis also contains an evaluation of the results for three materials which can be used in the production of a heat exchanger (aluminum, copper, steel).

Page generated in 0.025 seconds