Academic literature on the topic 'Mechanická účinnost'

Mikropolutanty v životním prostředí působí negativně na vodní ekosystémy a též představují potenciální riziko pro lidské zdraví. Zásadním zdrojem vnosu mikropolutantů do životního prostředí jsou městské ČOV, jejichž konvenční mechanicko-biologická technologie není na odstraňování mikropolutantů navržena. V této práci jsme testovali účinnost odstranění mikropolutantů řadou oxidačních (např. ozonizace, UV/H2O2, Fentonova reakce, borem dopovaná diamantová elektroda) a sorpčních (např. granulované aktivní uhlí GAU, zeolity) procesů. Účinnost odstranění vybraných léčiv (např. erythromycin, sulfamethoxazol, ibuprofen atd.) a metabolitů pesticidů (např. acetochlor ESA, metazachlor ESA) jsme testovali v jednorázových vsádkových testech. S přihlédnutím k ekonomickým i provozním parametrům byla pro následné testování v reálných podmínkách (poloprovozní měřítko) zvolena kombinace oxidace UV/H2O2 a sorpce na GAU. Mikropolutanty v modelové vodě byly úspěšně odstraněny z 91% (suma léčiv) a cca 100% (suma metabolitů pesticidů) při použití optimální dávky H2O2 5 mg/l a intenzity UV záření 4 kJ/m2 s následnou sorpcí na GAU. Tyto velmi slibné výsledky v současné době ověřujeme v pilotní jednotce pro dočištění reálného odtoku z městské ČOV. Abstract (EN) Micropollutants cause harm to aquatic ecosystems and can also negatively affect human health. Major sources of micropollutants input to aquatic environments are wastewater treatment plants due to their insufficient removal during the conventional mechanical-biological process. This study aimed to evaluate potential WWTP effluent post-treatment processes for the removal of selected pharmaceuticals and pesticides using oxidation (e.g., ozonization, UV/H2O2, Fenton, boron-doped diamond electrode) and sorption (e.g. granular activated carbon, zeolite) processes and their combinations. The removal of selected pharmaceuticals (e.g. erythromycin, sulphamethoxazole, ibuprofen) and pesticides (e.g. acetochlor ESA, metazachlor ESA) was tested in batch assays. The combination of UV/H2O2 and activated carbon adsorption was the most favorable in terms of removal efficiency and economic and operational parameters. This combination achieved the removal efficiencies of pharmaceuticals and pesticides of 91 and 100%, respectively, using an optimum H2O2 dose of 5 mg/L and UV intensity of 4 kJ/m2 followed by granular activated carbon adsorption. These promising results are currently adopted in a pilot-scale study for the post-treatment of a real WWTP effluent.

This master's thesis is concerned with the mechanical efficiency of cranktrain contact pairs in a combustion engine. In the introductory part, the fundamental terminology relating to the cranktrain is presented along with the specification of the areas of mechanical losses, greasing modes and types of wear. The following chapters describe the possibilities of eliminating mechanical losses of the cranktrain and the calculation methods that can be utilized to mathematically solve mechanical losses. The practical part includes the proposal of a calculation model and its use in the analysis of the cranktrain of Skoda 1.2 HTP engine. The last part of this thesis comprises modified alternatives of the standard cranktrain focusing on the elimination of mechanical losses. The evaluation of the results is presented in the conclusion of this thesis.

Master’s thesis handles about measurement on linear motors. Acts about set of two linear machines on one rail. One is motor and second is load. Thesis paies their mathematical description, control and measurement. It’s made measurement of the linear motor load characteristic. Next measurement have to do with losses in the converter. Is chosen measuring instrument t for measurement during working cycle. During working cycle has determine power eciency of entire drive.

Parameters that characterizes quality internal building environment come forth these days. One of the main reasons for the choice of the topic of this thesis is to ensure the quality of the internal environment and well-being during the usage of the buildings. Prevention of the excessive wall dampness is one of the basic conditions of a healthy and quality building environment. The thesis verifies reliability and compares the efficiency of the selected damp-proof materials and its joints. The first part deals with the influences that are reasons for the dampness of the buildings, earmark of an interest area, introducing of the valid legislation focused on the building redevelopment, consideration and evaluation of the building constructions in light of the dampness. The next part of the thesis sets main and partial targets and consecutive steps leading to fulfilment of the targets. Selection of the appropriate redevelopment procedures, materials and joints of the selected materials selected for the experiment realization follows. As this area is relatively large, we selected mechanical redevelopment methods reaching the walls and three most commonly used materials and its joints within the framework of the selected methods. There are three main steps set in the thesis: preparation of the methodology and experiment realization, measurement optimization and measurement within the laboratory and on the real buildings, comparison and evaluation of the measured values. Experimental part of the thesis took place between the years 2008 - 2011. Experiment realization comprises of material acquisition, building of the test samples and application of the single redevelopment measures. The next step includes measurement on the individual samples on the fixed measuring points. Measurements are evaluated through the mathematical statistical methods. Efficiency of the particular materials are compared and evaluated.

In the first part of the master’s thesis dealing with the increasing efficiency of induction motors there are briefly presented basic information about induction motors, followed by an overview of the losses of induction motors. The next part deals with the ways to increase efficiency of induction motors without increasing tooling costs. The practical part consists of four measurements of four induction motors, with their various mechanical adjustments to make comparing benefits of these modifications possible. The measured results are compared by a finite element method in Maxwell 2D Design program, in which the same motors are simulated as measured. Theoretical knowledge about the increase of efficiency is practically applied while being implemented in the simulations.

This diploma thesis deals with the issue of using fine powder of concrete recyclate. In this thesis, the theoretical expectations of milling are summarized as well as high energy milling. Afterwards professional articles, in which fine powder of concrete recyclate is successfully activated, are described and commented on. In the experimental part, there are 11 recipes of cement mortar and 3 recipes of concrete mixed. The benefit of using fine powder of concrete recyclate as a possible substitute for part of the cement is evaluated.

The thesis is focused on analyzing the current status of the technology used for cleaning flue gas from persistent organic pollutants, especially PCDD/F. For the three most commonly used methods of solution operational and energy efficiency comparison was made, where achievable energy export and the impact of the change in working conditions on the efficiency indicators of energy production and use of the energy was evaluated. In conditions we considered an alternative machine-technological solutions used for the final disposal of persistent organic pollutants resulting from the waste combustion in terms of additional operating costs and energy efficiency.

The master's thesis deals and introduces a single-phase inductions machines, the principle of operation, types of design and operating conditions. This thesis includes analysis of individual losses in the machine and reduce the possibility of different ways. After a theoretical proposal for reducing losses are measured by mass-produced single-phase induction machine. Further machine modifications proposed for reducing losses in the stator windings and designed a prototype machine with the adjustment of the magnetic circuit to reduce iron losses made by ATAS elektromotory Nachod a.s. The results are supplemented by a simulation using software Maxwell RMxprt and finite element method (FEM). Finally, they are compared to each machines modifications mainly in terms of energy consumption.

The main purpose of the thesis Automatic measurement of induction machine using LabVIEW was to develope an automated measuring system, which is used to perform tests of induction motors. The algorithm of the system is programmed in LabVIEW. In the practical part of this thesis, a measurement of the motor Atas Elektromotory Náchod a.s. T22VT512 is carried out, in order to verificate functions of the algorithm, and to perform tests of the motor to analyse losses. Another part of the work is dedicated to the electromagnetic calculation of the motor T22VT512. For this purpose, two softwares with different principles of calculation have been used. Firstly, the calculation is solved by an analytical based software called RMxprt. Secondly, the software Maxwell 2D is used to make the calculation of electric and magnetic fields by the finite element method.

The master’s thesis Improvement power parameter of small induction motors deals with issues of lowering the losses of small induction motors. The first part introduces with design and principles of operation of induction motors. Also introduces to theoretical problematic of losses, their lowering and measuring. In the practical part there are results of the measuring the losses in the induction motor ATAS Elektromotory Náchod a.s. T22VT512 (71-0512). There are proposed methods of increasing the efficiency of induction motor due to measuring and their verification in the Maxwell software. The last part is dedicated to measuring the losses of prototype motor from ATAS and comparison of results with previous motor.

This thesis deals with the design changes of intake and exhaust systems of naturally aspirated combustion engine with the aim to improve its dynamic characteristics. An overview of intake and exhaust tract designs (together with their impact on the engine efficiency) is provided in the introductory part of the thesis. Based on this knowledge, modifications of the intake and exhaust systems of Ford Windsor V8 engine were proposed and installed in a vehicle. A series of dynamic and static tests on chassis dynamometer were carried out in order to measure the impact of the changes on the torque curve. The impacts of the changes are presented in detailed analysis of power and torque characteristics with respect to the engine speed. The results are discussed and the possible causes of observed phenomena are identified.