Regenerative heat exchangers are established as a means of heat recovery in many industrial applications. The fixed-bed regenerators are mostly used to transfer heat from hot flue gas to cold air. In this work, several mathematical models of regenerators and several calculation methods were compared, while the preferred method is Willmott’s open method from 1964. Analysis of the influence of geometrical and operational parameters was carried out for the linear regenerator model.

Wastewater treatment performance of three pilot-scale packed-bed anaerobic digesters with walnut shell medium was researched for treating dairy freestall barn flushwater. Reciprocation mixing was evaluated as a means to lessen channelization in the media bed and to improve biogas production and organic matter removal at ambient temperatures. Reciprocation has been used in biological nitrogen removal systems to introduce air into the system to repeatedly oxygenate nitrifying biofilm along with mixing (Behrends et al. 2003), but the anaerobic systems benefit from mixing. Two tanks were used in each system, where one was full and one was empty at any given time. Water was repeatedly pumped from one tank to the other and back again (reciprocation). A key research objective was to determine the minimum reciprocation frequency (between 0-10 per day) while still maintaining moderate methane production and treatment performance. Broken walnut shells with a specific surface area of 360 m2/m3 were used as the packed media. Digester influent, which was pretreated to remove large solids, had the following characteristics: total solids (TS) of 5.5 g/L, volatile solids (VS) of 2.8 g/L, 5-day carbonaceous biochemical oxygen demand (cBOD5) of 800 mg/L, and chemical oxygen demand (COD) of 4340 mg/L. Average digesting liquid temperatures ranged from 14.1 to 23.6 °C. At 6-day theoretical hydraulic residence times (V/Q where V is Lliquid, which is volume of liquid occupying the digester pores, and Q is total daily influent flow) and 1 reciprocation per day, methane production was 0.060 ± 0.10 LCH4/Lliquid-day and at 10 reciprocations methane production 0.058 ± 0.14 LCH4/Lliquid-day (mean ± standard deviation of measurements over time). COD percent removals were both 51% at 6-day V/Q. Since multiple reciprocations did not appear to make a difference in methane production and treatment performance, fewer reciprocations were used in subsequent experiments. Higher flow rates were also used in subsequent experiments to accelerate sludge clogging and channelization in the walnut-shell bed and thereby allow detection of any advantage provided by reciprocation compared to an upflow reactor. At 0 and 1 reciprocations per day and 0.35 and 0.50-day V/Qs, respectively, methane production was 0.24 ± 0.08 and 0.23 ± 0.08 LCH4/Lliquid-day and COD percent removal was 17 and 22%. Over the study period of 226 days, walnut shell porosities decreased due to sludge accumulation from 0.68 and 0.64 (start-up or clean-bed) to 0.31 and 0.24 in the 1 and 0 reciprocation per day reactors. Sludge accumulation and channelization did not appear to be affected by reciprocation mixing on the scale of this study.

Diploma thesis is about development of program application for management maintenance of fixed assets for the companies ESOX, spol. s.r.o. and ESOX-PLAST s.r.o. In the first part of the work are mentioned theoretical backgrounds which where used to create diploma thesis. Further in the work there is evaluated the current situation of companies and also current situation of the solved problem. It follows by the creation of the application which single parts are described in the diploma thesis. At the conclusion there are summarized benefits of the program application and its assessment from an economic perspective.

Master's thesis solve problem with fixed asset's in company Antreg, a.s. Main focusis is oriented to the most important areas, especially the organisation and maintenance activity and taking care of assets.. Objective is to elaborate proposals for problems resulting from executed analysis.

Diploma thesis deals with constructional design of an experimental fixed-bed reactor for biomass combustion research. This device is designed to facilitate good control of the combustion process and collection of quality data, particularly temperature, pressure, gas composition and mass loss. Obtained data is for creating mathematical models of combustion of solid biomass in the fixed-bed.

This master´s thesis solves the problem of stationary viscous flow of incompressible fluids in thin layers of fluid film lubrication in fixed pad thrust bearings. The parametric computational model of oil domain was created for investigation the distribution of pressure, velocity and thermal fields together with the determination of the basic parameters as axial force, heating up and friction loss. Subsequently this model was applied for investigation influence of uneven bearing clearance. The problem task was solved by final volume method in Ansys CFX 12.0 software.

This thesis named Analysis of the impact of fixed obstacles near roads on the course of traffic accidents deals with the diversification of fixed obstacles near the roads, brief theory of road accidents, possible consequences and shows statistics of road accidents with a fixed obstacle. The aim is to perform analysis of real traffic accidents with a fixed obstacle with serious consequences for health, life and property and with the help of a computer simulation software to analyze the same accident again, but for the condition if the fixed obstacle was removed. Finally, the consequences of accidents are compared, the analysis are evaluated and the proposed measures to eliminate the consequences are assessed.

This master’s thesis deals with problems of financing the acquisition of fixed assets. The theoretical part focuses on defining fixed assets and describing possibilities of its financing. The analytical part describes particular fixed asset and informs about economical situation of the company. This part also compares lease financing, bank loans and equity financing. The final part recommends the best possible option for the acquisition of fixed assets.

There is an ongoing need for educational psychologists, researchers, policymakers, educators, and parents to continue to identify and understand the academic and nonacademic factors that influence academic achievement. Recent studies have documented the steady decline in the academic performances of students from Grades 7 to 9. The purpose of this study was to examine the statistical relationship between basic psychological needs satisfaction in relationship with caregivers, mindsets of intelligence, and academic achievement among secondary school students in the Commonwealth of Dominica. This study was grounded in the self-determination theory and mindsets of intelligence theory. A non-experimental correlational design using survey methodology was used for this study. Participants were 143 3rd year secondary school students ages 11 through 15. The participants’ academic achievement, mindsets of intelligence and their basic psychological needs satisfaction in relationship with their caregivers, were measured. The data were analyzed using standard multiple regression. The results of the study found a significant inverse relationship between the relatedness component of psychological needs satisfaction and academic achievement. Additionally, higher mindset of intelligence scores significantly predicted higher scores in math, English, and science in the participants first and second years of secondary school. The positive social change implications of this study may equip policymakers, teachers, and parents with the relevant information needed to design and implement programs aimed at improving the academic achievement of secondary school students

This essay is about flexibility in relation to employment protection through a gender perspective. It handles the regulations of fixed term employments and how they are regulated in collective agreements in different sectors. The sectors studied are chosen by statistics on male- and female dominated sectors to apply a gender perspective. 90 percent of Swedish workers are covered by collective agreements and many of the studied agreements differ markedly from both the regulation in the Swedish law and from each other. The study shows that depending on which sector you are working in your employment protection will differ. Especially in female dominated sectors the regulations of fixed term employments are even more flexible than the law and the regulations in male dominated sectors. According to the gender structure of the labor market, women have lower status, which could be an explanation to why the regulations tend to be less favorable for women. The result of the study shows that collective agreements in female dominated sectors tend to have regulations according to the Swedish law or less favorable than the law. The male dominated sectors on the other hand tend to have collective agreements that are stricter regulated than the law when it comes to the area of fixed term employments. By that said the regulations of fixed term employments seem through a gender perspective be better for men than for women.