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Control Techniques of Grid Connected PWM Rectifiers under Unbalanced Input Voltage Conditions
Bejvl, Martin ; Šimek, Petr ; Škramlík, Jiří ; Valouch, Viktor
Current-controlled voltage source converters are widely used in grid-connected applications,for example at ac drives with indirect frequency converters.The structure and parameters of the PLL are developed and proposed in order to cope with the grid containing both the positive and the negative sequence component, and minimize the wrong frequency transients during phase angle steps and also in the start-up stage. The DSC technique was realised. There is also necessary to compensate the negative sequence component in the grid voltage. The negative sequence component of the grid voltage causes ripple of the dc voltage in the intermediate circuit. Several sophisticated topologies of converter current controller were developed, simulated and tested for this purpose. Results of simulation and experimental tests are provided to evaluate different current control schemes and phase locked loop techniques.
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Differences in CO2 Extraction of Vegetable Oils, Essential Oils, and Minor Components from Plants
Sovová, Helena
Significant progress in understanding the phenomena that control supercritical fluid extraction from plants was made in the last years and is reflected in the literature. Combination of chemical engineering approach and botanical knowledge has appeared to be fruitful for the choice of extraction model and even for the prediction of extraction kinetics. This contribution refers to the papers utilizing knowledge of plant microstructure and location of extracted substances together with extraction equilibrium and attempts to specify the differences among extraction kinetics of vegetable oils, essential oils, and other substances. The most abundant substances like vegetable oils in seeds can be regarded in first approximation as non-interacting with plant matrix, in contrast to the minor components whose equilibrium concentration in CO2 is affected by their adsorption on matrix and often also by co-extracted substances.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22012102414100 - PDF
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Development of Process for Disposal of Plastic Waste Using Plasma Pyrolysis Technology and Option for Energy Recovery
Punčochář, Miroslav ; Ruj, B. ; Chatterjee, P.K.
Plasma pyrolysis is an innovative technology for transforming high calorific plastic waste into a valuable synthesis gas (syngas) by means of thermal plasma. The process developed is a drastic non-incineration thermal process, which uses extremely high temperature in an oxygen-starved environment to completely decompose input plastic waste into syngas, composed of very simple molecules viz : CO, H2 and hydrocarbons. A 20 kg/hr capacity plasma arc pyrolyser for treatment of plastic waste as well as energy recovery options from waste plastic has been indigenously designed, developed, installed and studied its performance at the Central Mechanical Engineering Research Institute (CSIR), Durgapur.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102414090 - PDF
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Analysis of logistics in freight transport technologies
VÁCHOVÁ, Monika
Bachelor thesis deals with the analysis individual technologies applied in logistics trucking transport.The thesis is focused on the information and satellite technologies. In terms of information technology were introduced various systems used in business ČSAD JIHOTRANS and then made a comparison. In terms of satellite technology was introduced control , navigation and tracking systems used in this enterprise. The next part dealt with freight and construct a calculation I estimate the cost of freight vehicles. Based on the estimates were submitted its own proposals for improvement.
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The technical monuments as a part of tourism in the region of Týn nad Vltavou
DOBEŠ, Jakub
This thesis processes a database of technical monuments in the city of Týn nad Vltavou and its surroundings. There was made a survey and controlled interviews with local businessmen and on its basis two plans of tourist routes and one cycle route were created. These plans of technical monuments include also its financing and project of new bike rentals.
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Ethics of auditors in practice
SVOJŠOVÁ, Pavlína
In my thesis I evaluated and assessed the activities of auditors in relation to the ethics of behavior in terms of legislation of the Czech Republic. I focused on the published cases of misconduct of auditors and the subsequent punitive sanctions. Ethical behavior is the basis for the auditor's professionalism. In connection with the accounting scandals and falsification of accounting and audit reports, the public began to discuss - among other things - auditors' liability for fraud detection leading to distorted accounts of the entities and the principles of ethical behavior started to get into the spotlight of auditors?, which was later enshrined in legal and professional standards including Code of Ethics of the International Federation of Accountants (IFAC). Expectations of many users of financial statements from the auditor's report are too high and usually go up beyond what the auditor can actually verify and confirm. However, it must be acknowledged that not all auditors are sufficiently aware of their responsibilities in relation to the distortion of financial statements due to fraud or misconduct, and adequately adapt their audit procedures due to them. Certainly worth mentioning is the most visible impact of accounting scandals in the accounting and auditing profession - the fall of Arthur Andersen, one of the former "Big Five" auditing firms. Accounting profession has responded by developing and tightening ethical standards with an emphasis on the conduct of professional accountants in the public interest, not only in the interests of individual clients or employers. The role of audit in society is irreplaceable. Quality of the audits undertaken, however, ultimately depends on the auditor's discipline and education, the control of the Council Chamber and also public oversight of auditing, as well as pressure of the users of financial statements and of the representatives on the appropriateness and quality of outputs. Ethics in the auditor's work and its compliance in life are the things that determine auditor?s reputation.
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Score of combine harvester with a different threshing device at harvest of cereals and oilseed rape in the business of agricultural production
HRACH, Milan
The purpose of this work was to compare aktivity and grade work combine harvester with different threshing system at harvesting a grain and oilseed rape in the business of agricultural production. Work was focuse on the size harvesting losses, grade grind and spreading crop residues, influence on the moisture of harvested crops on the size losses grade grind and spreading crop residues, throughput combine harvester, analysis of performance and consumption fuel. Work is complete about principal parametr agricultural operations, principal parametr owner machines and simply analysis of operating and investment costs. Although combine harvester didn't work at same land, measurement was done in the most consistent as possible in harvested condition regarding the weather, terrain, etc. From results are clearly that almost all the results achieved best results with a conventional combine harvester threshing mechanism Claas Lexion 580. Exception was only throughput at harvest of winter oilseed rape, which had machine John Deere S 690 with axial threshing of 1.23 kg ha-1 higher than Claas Lexion 580. Consumption fuel was lower at harvest of winter wheat with procrastination straw on the line by machine Claas Lwxion 670 with value 11,0 l.ha-1. . When shredding straw was reached average values for all combine. The worst grind and spread straw demonstrated combine harvester John Deere S 690 where avoid spreading crop residues over the entire stroke. All machines accomplish agro-technical requirements for the combine in terms of losses off 1,5 % in direct harvest, performance, throughput, quality scatter chop, shred the quality of crop residues and working speed. Results this work convince me to recommend harvester Claas Lexoon 580 especially for large agricultural business and for service businesses with minimum efficiency 1 340 ha.rok-1 . For smaller business or business with higer structure of livestock production I would have chosed thresher with straw walker technology separation device and to Claas Lexion 670. Combine harvester John Deere S 690 U would advised more for service businesses and large business engaged in growing corn for grain with minimum area coverage. For both machines I would choose the cutter adapter on the frame 9 meters.
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Trapped Vortex Ring
Tesař, Václav
Paper discusses an almost unknown and yet interesting operating principle of fluidic nomoving-part devices for flow control. The principle is based on the properties of vortex rings. A standing vortex ring is kept in a semi-toroidal recession positioned opposite to an annular nozzle from whichissues an annular fluid jet. The ring can exist in the recession with two alternative senses of rotation so that the annular jet is led to either the central exit through the centre of the vortex, or to the outer spacepast the outer vortex circumference.
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Deployment of corporate audio-video technology
Nikl, Martin ; Havránek, Martin (advisor) ; Matyáš, Matyáš (referee)
This thesis deals with the possibility of connecting, automating and controlling audio/video hardware. In the theoretical part the author deals with input and output A/V devices, A/V interfaces communication interfaces, possibility of connecting automation elements and a room control. It explains terms relating to the audio/video topic.
The practical part suggests a complete design and implementation of a showroom to present the portfolio of Colsys company, which demonstrates functions of the control system Crestron, such as controlling projectors, video matrices, sound equipment and building automation (lights, air conditioning, blinds, etc.). First part of this section deals with defining the requirements for individual devices. The next step was the selection of suitable components based on fulfilling the set criteria and the budget. After that a check of compatibility was performed and room layout was designed, which contained electrical layout and a room blueprint. Final step of this section was designing the user interface and its realization in order to create the control unit program.
Based on the theoretical part the author created a chapter titled Recommendation, which is verified in the practical part by creating a fully functional showroom for Colsys company, which also serves as a meeting room.
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