Equipment for the Measurement of the Force Effect of the Water Jet

Import 29/09/2010V úvodu bakalářské práce je popsáno několik typů používaných proudů v praxi. Dále užití vodního paprsku při dělení materiálu. Bakalářská práce se zabývá teorií vodního paprsku ve vzduchu a ve vakuu. Hlavním obsahem bakalářské práce je návrh zařízení pro měření silového účinku vodního paprsku. V této práci jsou navržena dvě zařízení. První zařízení obsahuje nádrž s čerpadlem a potrubí. U druhého návrhu zařízení je nádrž, čerpadlo a potrubí nahrazeno vysokotlakým čističem. Dále jsou v práci uvedeny výpočty pro stanovení silového účinku vodního paprsku. V závěru je vybráno vhodnější řešení. Součástí práce jsou vytvořené návody do cvičení pro měření silového účinku vodního paprsku.In the introduction of the Bachelor thesis are described several types of jets, which are used in practice. Next I described using of the jets for material separation. Bachelor thesis deals with the theory of the water jets in the air and in the vacuum. The main content of the Thesis is proposal of equipments for measurement power effect of the water jet. In this work are proposed two equipments. The first equipment contains tank with the pump and pipeline. In the second equipment is tan pump and pipeline supersede by high pressure cleaning. Next in Bachelor thesis are calculations for establishment of effective power water jet. At the end the best solution is selected. The thesis also includes instruction for measurement of power effect of water jet.Prezenční338 - Katedra hydromechaniky a hydraulických zařízenívelmi dobř

Testing of a Radiant Wall Cooling System with Pipes Coupled to Aerated Blocks

Thermal output, surface temperatures, and supply and return water temperature were measured for a wall cooling system involving pipe attached to a wall section made of thermally insulating blocks. The experiment was performed for warm climatic conditions typical of, e.g., summer in Central and Northern Europe. The outdoor environment was simulated by a climatic chamber while the indoor climate was simulated by attaching a hotbox to the wall surface. The sensitivity of thermal output to several design parameters was investigated by 2D numerical simulations. The measurements showed a fast thermal response of the wall system. The cooling output was 38.3 W per m2 of the cooling area which equalled about 4.8 W/m2 per 1 K temperature difference between water and hotbox. The lowest surface temperature of 19.6 °C was measured at the pipe. Thus, the cooling output could be enhanced by reducing the surface temperature closer to the dew point temperature. The temperature of water in the pipe was very close to the surface temperature. It was illustrated how this characteristic of the wall cooling system tested positively affects the efficiency and cooling capacity of an air-to-water heat pump

Investigation of polyurethane electrospinning process efficiency

The electrospinning process efficiency of different PUs has been investigated. Specific attention has been paid to understand the role of PU soft segments and synthesis type on the stability of the PU solution and electrospinning process as well as on the quality/property changes of the produced nanofibres. PU samples before and after the process were analyzed rheologicaly and relaxation spectra were determined for all of them from frequency dependent loss and storage moduli measurements. It has been found that rheological analysis of PU, which is used for electrospinning process, can be useful tool from electrospinning process efficiency and optimization point of view. Nanolayers homogeneity during several hours of manufacture in optimized electrospinning process is proved by selected properties from aerosol filtration. © 2009 American Institute of Physics

Morphology of nano and micro fiber structures in ultrafine particles filtration

Selected procedures permitting to prepare homogeneous nanofibre structures of the desired morphology by employing a suitable combination of variables during the electrospinning process are presented. A comparison (at the same pressure drop) was made of filtration capabilities of planar polyurethane nanostructures formed exclusively by nanofibres, space polycarbonate nanostructures having bead spacers, structures formed by a combination of polymethyl methacrylate micro- and nanofibres and polypropylene meltblown microstructures, through which ultrafine particles of ammonium sulphate 20-400 nm in size were filtered. The structures studied were described using a new digital image analysis technique based on black and white images obtained by scanning electron microscopy. More voluminous structures modified with distance microspheres and having a greater thickness and mass per square area of the material, i.e. structures possessing better mechanical properties, demanded so much in nanostructures, enable preparation of filters having approximately the same free volume fraction as flat nanofibre filters but an increased effective fibre surface area, changed pore size morphology and, consequently, a higher filter quality. © 2011 American Institute of Physics

Is it really advantageous to operate proximal femoral fractures within 48 h from diagnosis? – A multicentric retrospective study exploiting COVID pandemic-related delays in time to surgery

Objectives: Hip fractures in the elderly are common injuries that need timely surgical management. Since the beginning of the pandemic, patients with a proximal femoral fracture (PFF) experienced a delay in time to surgery. The primary aim of this study was to evaluate a possible variation in mortality in patients with PFF when comparing COVID-19 negative versus positive. Methods: This is a multicentric and retrospective study including 3232 patients with PFF who underwent surgical management. The variables taken into account were age, gender, the time elapsed between arrival at the emergency room and intervention, pre-operative American Society of Anesthesiology score, pre-operative cardiovascular and respiratory disease, and 10-day/1-month/6-month mortality. For 2020, we had an additional column, “COVID-19 swab positivity.” Results: COVID-19 infection represents an independent mortality risk factor in patients with PFFs. Despite the delay in time-to-surgery occurring in 2020, no statistically significant variation in terms of mortality was detected. Within our sample, a statistically significant difference was not detected in terms of mortality at 6 months, in patients operated within and beyond 48 h, as well as no difference between those operated within or after 12/24/72 h. The mortality rate among subjects with PFF who tested positive for COVID-19 was statistically significantly higher than in patients with PFF who tested. COVID-19 positivity resulted in an independent factor for mortality after PFF. Conclusion: Despite the most recent literature recommending operating PFF patients as soon as possible, no significant difference in mortality was found among patients operated before or after 48 h from diagnosis

Convergence between US GAAP and IFRS: Current Status and Outlook for the Future

Bakalářská práce se zabývá analýzou procesu konvergence mezi IFRS a US GAAP, a analýzou vybraných přetrvávajících rozdílů mezi těmito účetními systémy. Za tímto účelem předkládá tato práce v první části shrnutí dosavadního vývoje procesu konvergence mezi IFRS a US GAAP, a hodnocení jeho dosavadní úspěšnosti. Druhá část práce se zaměřuje na představení vybraných důležitých přetrvávajících rozdílů mezi IFRS a US GAAP, a současně ukazuje dopady vybraných rozdílů na konkrétních účetních případech. Třetí část práce se zaměřuje na analýzu současného stavu tohoto procesu konvergence, a představuje možnosti jeho dalšího vývoje. Poslední část práce celkově hodnotí problematiku konvergenčního procesu a analyzuje důvody, proč nebyl tento proces příliš úspěšný.Katedra financí a účetnictvíObhájeno2112-12-06The bachelor thesis focuses on analysis of the process of convergence of IFRS and US GAAP, and also on analysis of selected differences between the two financial reporting systems. The first part of the thesis presents a summary of the history of the convergence process, and assesses how successful it has been so far. The second part of the thesis focuses on selected important differences between IFRS and US GAAP and shows the impact of the differences on specific situations. The third part analyzes the currents status of the convergence process and discusses the possibilities for its future development. The last part of the thesis provides an overall evaluation of the convergence process and analysis of why it has not been very successful

Using Live Script for modelling and experimental identification education

Bakalářská práce je věnována problematice matematicko-fyzikální analýzy a experimentální identifikace dynamických systémů a jejím cílem je vytvoření studijního systému založeného na využití nástroje Live Script výpočetního systému MATLAB.The bachelor thesis is devoted to the issue of mathematical-physical analysis and experimental identification of dynamic systems and the creation of a study system based on Live Script tool of MATLAB computational environment.Fakulta elektrotechniky a informatikyCílem práce bylo vytvořit ukázkové úlohy pro výuku modelování a experimentální identifikace za použití nástroje Live Script MATLABu. Analytické modely jsou vytvořeny v Simulinku a také pomocí nástroje Live Script, kde je uveden také popis systému a odvození modelu. Experimentální modely jsou zpracovány pouze pomocí Live Script. Cíl bakalářské práce byl splněn.Dokončená práce s úspěšnou obhajobo

Determination of Pressure Losses in Pipe Fittings Using Numerical Modeling

Import 03/08/2012V mé diplomové práci jsem se zabýval laboratorním měřením a numerickým modelováním místních ztrát na tvarovkách potrubí. Úvod diplomové práce je věnován teorii vzniku místních ztrát zejména u náhlého rozšíření a zúžení průřezu potrubí a výpočtu hodnoty ztrátového součinitele. V další části jsou zpracovány výsledky získané z laboratorního měření, které probíhalo v laboratořích katedry hydromechaniky a hydraulických zařízení (338). Veškeré potřebné hodnoty a závislosti jsou uvedeny v tabulkách a grafech. Hodnoty ztrátového součinitele jsem vyhodnocoval pro přítokovou a odtokovou rychlost. Následně jsem na základě laboratorního měření provedl numerické modelování proudění pro náhlé rozšíření a zúžení průřezu. Samotnému modelování předchází tvorba modelu a výpočetní sítě. Na závěr diplomové práce jsem provedl porovnání hodnot ztrátových součinitelů z laboratorního měření a numerického modelování s hodnotami uváděnými v literatuře.In my thesis I deal with laboratory measurements and numerical modeling of local losses in a pipe fittings. The beginning of the thesis is devoted to the theory of local losses especially in case of sudden expansion and contraction of the pipe cross-section and definition of the loss coefficient is described. In the next section the results obtained from laboratory measurements are evaluated. Experimental investigation was carried out at the Department of Hydromechanics and Hydraulic Equipment. All obtained data and functions are presented in tables and graphs. Value of local losses I evaluated for inlet and outlet velocity. In another part numerical modeling is performed based on the laboratory measurement. The definition of geometry and generation of the model grid is described at the beginning of the numerical modeling. At the conclusion of the thesis the loss coefficients obtained by laboratory measurements and numerical modeling are compared with the values reported in the literature.338 - Katedra hydromechaniky a hydraulických zařízenívelmi dobř

Introduction into the theory of optimum currency areas

The study provides a comprehensive overview of the development of the Optimum Currency Area theory up to date. It first concentrates on examination of the broader discussion on different exchange rate regimes and their appropriateness for different economies. It then turns to the basic issue of the theory - to determine and study the preconditions which countries (or regions) aspiring to join a monetary union must fulfill in order to ensure that they will benefit from joining rather than be affected adversely. This study presents a critical evaluation of these preconditions by including the most recent developments in the study of the respective areas. It also extends the debate by discussing issues which have so far not been explicitly pursued by the theory as characteristics of an optimum currency area.optimum currency areas, monetary unions, European monetary union