This thesis explores the utilization of FEM software ANSYS in the analysis of the real blade wheel of a radial compressor used in small turbine aviation motors. This apparatus is made by První brněnská strojírna a.s., and its detached site in Velká Bíteš where it has the aviation engineering division. The aim of this thesis is a comprehensive blade wheel analysis composed of several steps. These steps include static and elasto-plastic strength analysis, which describes stress distribution and its assessment from the perspective of boundary conditions of elasticity during the use of the Hooke and the non-linear model of the material. Another step is dynamic analysis; in this case modal analysis, which describes the frequencies and its waveforms. The last part of the thesis contains thermal analysis while considering stationary and non-stationary thermal field. The analysis is then transformed into thermal-stress coupled analysis, which describes stress distribution resulting from thermal expansion of the material. The thesis follows the process of calculation simulations that are used during the design of a real impeller, thus before the creation of a prototype that undergoes real experiments.

Huminové kyseliny představují hlavní součást půdní organické hmoty. Jedná se o všudypřítomné sloučeniny s komplexní chemickou a fyzikálně-chemickou strukturou. Předkládaná práce shrnuje několik způsobů modifikací huminových kyselin provedených za účelem úpravy jejich vlastností. V první části byl studován vliv vzdušné oxidace lignitu na velikost výtěžku a fyzikálně-chemický charakter produkovaných regenerovaných huminových kyselin. Druhý krok představoval snahu stabilizovat strukturu lignitických huminových kyselin a zlepšit zádrž vody. Bylo provedeno síťování pomocí formaldehydu a karbodiimidů, které předpokládá vznik nových kovalentních vazeb v různých částech struktury huminových kyselin. Produkce zesíťované struktury byla motivována snahou vytvořit systémy podobné hydrogelům, založené na huminových látkách s možností úpravy jejich reaktivity a retence vody. Chemické složení a fyzikálně-chemické vlastnosti připravených vzorků byly studovány různými metodami, mezi nejdůležitější patří DSC a NMR relaxometrie. Chemické složení bylo studováno pomocí FTIR a elementární analýzy za účelem posoudit a porovnat změny s původním neupraveným vzorkem. Stability vzorků byly stanoveny pomocí termogravimetrie. Nejdůležitějším sledovaným parametrem této práce byla změna hydratačních charakteristik. K jejich studiu jsme vyvinuli a aplikovali několik nových termoanalytických a NMR relaxometrických přístupů. Ve snaze napodobit přírodní procesy byla studována sorpce vody huminovými kyselinami z prostředí s kontrolovanou vzdušnou vlhkostí. Byly pozorovány kvalitativní a kvantitativní hlediska sorpce vody. Zesíťování za použití formaldehydu způsobilo snížení sorpční kapacity vlhkosti. Tato změna je připisována separaci funkčních skupin a menší strukturní kompaktnosti. Zesíťované huminové kyseliny dále vykazovaly rychlejší příjem vody a přibližně třikrát větší kapacitu zádrže vody než původní huminové kyseliny. V případě použití karbodiimidu (ve vodě rozpustného N-Ethyl-N-(3-dimethylaminopropyl)karbodiimidu (EDC)) obsahovaly výsledné produkty 14–40 % původních karboxylových skupin. I přesto tyto látky překonaly schopnost sorpce vlhkosti původního nemodifikovaného vzorku o 10–14 % po kondiciaci v prostřední se 100% relativní vzdušnou vlhkostí. Navzdory rigidnější struktuře vykazovaly EDC deriváty rychlejší bobtnání a dosáhly téměř stejné kapacity zádrže vody po 18 dnech jako původní vzorek. Vzorky modifikované karbodiimidy vykazovaly známky degradace již po 3–9 dnech což částečně snižuje jejich využitelnost. Získané výsledky naznačují, že kapacita zádrže vody, kinetika bobtnání a schopnost sorpce vlhkosti huminových kyselin nejsou výhradně určeny koncentrací karboxylových skupin, nebo dalších polárních fragmentů, ale také jejich vzájemným rozmístěním a distribucí velikosti pórů na povrchu a také uvnitř struktury. Získané poznatky této studie mohou sloužit například k produkci půdních kondicionérů založených na huminových kyselinách, tj. remediačních preparátů s požadovanými, ale především nastavitelnými schopnostmi poutat a následně uvolňovat vodu do okolního prostředí. V neposlední řadě přispějí uvedené závěry ke zkvalitnění základního porozumění procesu hydratace v modifikovaných a původní vzorcích, což je přínosné ve vztahu k objasnění hydratace komplexních přírodních systémů a to zejména přírodní organické hmoty.

Products manufactured by aluminium casting have become very popular and already replaced many parts that were once produced by iron and steel casting. This trends upwards especially in the automotive industry as it has become extremely important to reduce vehicle weight due to environmental requirements and economical aspects. This popularity of aluminium alloys could be ascribed to their light weights and many other advantages including excellent castability, good corrosion resistance, good thermal and electrical conductivity, good machinability, low melting temperatures and minimal gas solubility with the exception of hydrogen. The most important alloy group among casting alloys is Aluminium Silicon (Al - Si).   Al-Si alloys must undergo a specific melt treatment procedure prior to casting. This treatment consists of several steps including degassing of hydrogen, grain refinement and eutectic modification. The aim of this study is to make an assessment of the metal treatment process of an (Al-Si) casting alloy at Unnaryd Modell AB for the purpose of improving the melt conditions and thus the quality of the final product. A rotary degasser provided by Foseco is also tested instead of the traditional tablet degassing method to see if this technique would result in any significant improvement of the melt quality. The results show that Unnaryd modell AB follows a proper treatment routine. It shows moreover that the rotary degassing is superior to the tablet degassing in many aspects including the level of degassing achieved, time efficiency, environmental consideration and personnel security.

A composite part manufacturing mold was considered one of the most important factors that affected a successful composite part manufacturing process for this research. A highly durable surface was required for the mold to prevent surface damages and increase mold life. A high surface finish quality of the mold improved the surface quality of the composite part and lowered the demolding force. However, the surface of additively manufactured fiber reinforced composite molds usually had lower durability and surface finish quality compared to traditional metal molds. To solve these issues, the author applied an additional coating on top of the additively manufactured fiber reinforced composite mold surface. A thermal analysis of the additively manufactured fiber reinforced composite material and the coating material were performed to select an applicable coating technique and coating material. The thermoset polymer coating with ceramic particles that was applied with a liquid spray coating technique was selected as a coating material. Various surface property tests were performed to evaluate the coated surface compared to the non-coated surface. The additively manufactured fiber reinforced composite test specimen manufacturing process and the coating application process were demonstrated in this study. The surface durability of the test specimens was tested using a surface hardness test and an abrasion resistance test. The surface performance of the test specimens was measured using a surface roughness test and a demolding test. The sustainability of the coating material on the additively manufactured fiber reinforced composite was tested using coefficient of thermal expansion (CTE) test, coating adhesion test, and mold life experiment. In the mold life experiment, the non-coated and coated mold were used for multiple composite part manufacturing processes to investigate how the coating affected the life of the mold. The test results showed that the coated surface had a significantly improved surface abrasion resistance and demolding performance. However, the coating did not significantly improved surface hardness and roughness with the coating. The adhesion strength of the coating was not degraded even there was a coefficient of thermal expansion (CTE) mismatch between the additively manufactured fiber reinforced composite and the coating material. The coated additively manufactured fiber reinforced composite mold was able to be used for multiple autoclave composite part manufacturing cycles. The coating covered most of the small voids on the mold surface and provided a more homogeneous surface compared to the non-coated mold, but the voids which could not be covered with the coating caused a chipped coating issue. Once the chipped coating occurred, the size of chipped coating got larger each time the tool was used for a composite part manufacturing cycle. Although the additional coating provided some improvements for the surface properties, the coating applied in this research could not be an ultimate solution to meet all the surface property requirements for composite part manufacturing mold.

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Over time the level of inoculant will decrease due to fading and this needs to be compensated bymore additions of inoculant. When casting CGI400 at Scania a one-step method is used, and the inoculant additions are based on the last ladle from the previous oven. Longer stops in production will result in the previous oven not being representable and more inoculant should be added. A method to establish the inoculation level of the base iron in the oven would make it easier to control the process. This study was about inoculation measurements with the help of thermo- analysis of the melt in the oven to get a better understanding how it fluctuates between ovens and changes over time. The study is also about how to implement this tool into production in a foundry. With the help of thermo- analytic measurements, the inoculation level of the melt was established, and the method was also used to see how the level of inoculant changed over. To establish the inoculation additions needed, the saturation point of inoculant was investigated. The results from the study shows that the starting level of inoculant is too low in the melt it also shows that the inoculation level fluctuates over time. The conclusions that can be drawn from this study is that thermos analysis can be used in production to establish the inoculation level, but moremeasurements needs to be conducted to determine its accuracy. / Över tid så minskar ympnivån i en smälta på grund av fading och detta måste kompenseras med mertillsatser av ymp. Vid gjutning av CGI400 på Scania används en en-stegs metod där man baserar ymptillsatsen i skänken på vad ympnivån var i sista skänken från den tidigare ugnen. Vid längre produktionsstopp kommer inte ympnivån från ugnen innan vara representativ utan mer ymp måste tillsättas. En metod för att bestämma ympnivån av basjärnet i ugnen skulle göra det lättare att styra processen. Denna studie handlar om ympmätning med hjälp av termisk analys i bas smälta för att få en bättre förståelse för hur den fluktuerar mellan ugnar och ändras över tid. Studien handlar också om hur man ska kunna applicera denna mätmetod i produktionen på ett gjuteri. Med hjälp av termo analytiska mätningar skulle grundnivån av ymp i smältan bestämmas och även för att se hur nivån ändrades över tiden. För att bestämma tillsatsen av ymp som borde tillföras undersöktes mättnadspunkten av ymp och hur den kunde tillsättas i skänk. Resultaten från studien visar att grundnivån av ymp är för låg och resultaten visar också att nivån av ymp fluktuerar både upp och ner ökar tid vilket inte var vad man hade förväntat sig och även det finns flera faktorer som kan påverka nivån. Slutsatsen som kan dras är att termisk analys kan användas i produktion för att bestämma ympnivån, men mer mätningar behövs för att bestämmadess noggrannhet.

The order of OH groups in the crystal structure of SbC2O4OH, a potential precursor in the synthesis of ternary oxides, was debated. Neutron diffraction on the deuteride SbC2O4OD revealed disordered OD groups with half occupation for deuterium atoms on either side of a mirror plane (SbC2O4OD at T = 298(1) K: Pnma, a = 582.07(3) pm, b = 1128.73(5) pm, c = 631.26(4) pm). O–H stretching frequencies are shifted by a factor of 1.35 from 3390 cm−1 in the hydride to 2513 cm−1 in the deuteride as seen in infrared spectra. SbC2O4OH suffers radiation damage in a synchrotron beam, which leaves a dark amorphous residue. Thermal decomposition at 564 K yields antimony oxide, carbon dioxide, carbon oxide, and water in an endothermic reaction. When using SbC2O4OH as a precursor in reactions, however, ternary oxides are only formed at much higher temperatures.

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No description available.

<p>As a cost-effective, healthy, and environmentally friendly personal mode of transportation, electric bicycles (E-bikes) are gaining an increasing market share from conventional bicycles and automobiles. Considering the legal rules in Ontario, Canada, a 500W motor makes the E-bike more attractive for travelling use. At the same time, the simple structure, high torque and power density, as well as the low cost of the switched reluctance machine (SRM) makes it a strong candidate for E-bikes.</p> <p>In this thesis, a 3-phase, external-rotor SRM with 6 stator poles and 10 rotor poles is designed for E-bike. The design of an external rotor arrangement of the 6-10 SRM topology has not previously been reported, hence it offers a new contribution to the published works. The machine design is initiated by the output power equation and is followed by a comprehensive finite element analysis (FEA). The external-rotor arrangement is chosen to facilitate ease of integration into the wheel hub structure of a typical pedal bicycle. The increasing rotor poles yield improved torque ripple reduction than more conventional (i.e. 6-4, 12-8 etc.) SRM design, which is an essential feature for low speed rider comfort.</p> <p>A new torque ripple reduction control scheme is investigated. Although the comparison shows that the torque sharing function has more positive result than angular position control with regards to torque ripple, this is at the expense of higher losses. Detailed thermal analysis ensures this machine is suitable to require no additional cooling system. The final machine design is experimentally tested via a full system prototype. Results highlight some limitation of the 2-D FEA in terms of the winding inductance calculation. Here, the end winding introduce more influence on short thickness machine, which will reduce its output power. However, its power-speed curve shows that this prototype machine has very strong overload ability.</p> / Master of Applied Science (MASc)