The motion of shock waves is important in many fields of engineering and increasingly so with medical applications and applications to inertial confinement fusion technologies. The flow structures that moving shock waves create when they encounter a change in area is complex and can be difficult to understand. Previousresearchers have carried out experimental studies and many numerical studies looking at this problem in more detail. There has been a discrepancy between numerical and experimental work which had remained unanswered. One of the aims of this project is to try and resolve the discrepancy between numerical and experimental work and try to investigate what experimental techniques are suitable for work of this type and the exact way in which they should be applied. Most previous work has focused on sharp changes in geometry which induce immediate flow separation. In this project rounded corners will also be investigated and the complex flow features will be analyzed.Two geometries, namely a sharp 172 degree knife-edge and a 2.8 mm radius rounded corner will be investigated at three experimental pressure ratios of 4, 8 and 12 using air as the driver gas. This yields experimental shock Mach numbers of 1.28, 1.46 and 1.55. High-speed schlieren and shadowgraph photography with varying levels of sensitivity were used to qualitatively investigate the wave structures. Particle image velocimetry (PIV), pressure-sensitive paint (PSP) and traditional pressure transducers were used to quantify the flow field. Numerical simulations were performed using the commercial package Fluent to investigate the effect of numerical schemes on the flow field produced and for comparison with the experimental results. The sharp geometry was simulated successfully using an inviscid simulation while the rounded geometry required the addition of laminar viscosity. Reynolds number effects will be only sparsely referred to in this project as the flows under investigation show largely inviscid characteristics. As the flow is developing in time rather than in space, quotation of a distance-based Reynolds number is not entirely appropriate; however, Reynolds number based on the same spatial location but varying in time will be mentioned. The density-based diagnostics in this project were designed to have a depth of field appropriate to the test under consideration. This approach has been used relatively few times despite its easy setup and significant impact on the results. This project contains the first quantative use of PIV and PSP to shock wave diffraction. Previous studies have almost exclusively used density-based diagnostics which, although give the best impression of the flow field, do not allow for complete analysis and explanation of all of the flow features present. PIV measurements showed a maximum uncertainty of 5% while the PSP measurements showed an uncertainty of approximately 10%.The shock wave diffraction process, vortex formation, shear layer structure, secondary and even tertiary expansions and the shock vortex interaction were investigate. The experimental results have shown that using one experimental technique in isolation can give misleading results. Only by using a combination of experimental techniques can we achieve a complete understanding of the flow field and draw conclusions on the validity of the numerical results. Expanding the range of the experimental techniques currently in use is vital for experimental aerodynamic testing to remain relevant in an industry increasingly dominated by numerical research. To this end, significant research work has been carried out on extending the range of the PSP technique to allow for the capture of shock wave diffraction, one of the fastest transient fluid processes, and for applications to low-speed flow (< 20 ms−1).

Submitted by Luis Ricardo Andrade da Silva (lrasilva@uefs.br) on 2016-02-22T22:50:07Z No. of bitstreams: 1 Disserta??o_Alex_RGV_Final2.pdf: 2862200 bytes, checksum: e222cf5496c76484ec34f8fdd9012d23 (MD5) / Made available in DSpace on 2016-02-22T22:50:07Z (GMT). No. of bitstreams: 1 Disserta??o_Alex_RGV_Final2.pdf: 2862200 bytes, checksum: e222cf5496c76484ec34f8fdd9012d23 (MD5) Previous issue date: 2015-11-16 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / In Brazil, research on Arecaceae pollen grains are related to melissopalynology, the palynotaxonomy, being scarce the physiology of pollen. Reproductive biology studies pollination are of great importance in different cultures, from their results can obtain parameters to be used to obtain a considerable increase in the production of croops, as well as the size and quality of fruits, helping for good economic income of the producers. In vitro pollen germination also allows you to check its viability and reproductive strength, and are important tools in breeding programs of plants, assisting in the selection of the most effective genotypes and training hybrids. The chapter one of this work consists of evaluation of the type of culture medium and implications on the choice of micronutrients which form part of its composition, as well as the pretreatment of specimens. It was observed that oil palm pollen (Elaeis guineensis Jacq.) Showed an increase in germination rates after being dissected for a period of four hours and the culture medium with only boric acid and calcium nitrate, in addition to the power source (sucrose) are efficient to display their germination potential. Chapter two contained in the evaluation glycoconjugate (lectins) on the pollen germination of oil palm, which was discussed metabolic interactions of these processes. Lectins are important regulators and operate in recognition and acknowledgment of pollen on the pistil and can act as genetic incompatibility factors. Germination was evaluated in BCa means (boron and calcium) with the addition of lectins: Crotalaria pallida lectin (CPL), Concanavalin A (ConA) and Jacalin (JAC) in two concentrations. An increase of the germination rate in the presence of ConA and CPL lectins and inhibition in the presence of JAC. The results of this study were valuable, since aggregate informative values and extend discussions on the processes involving the germination of pollen grains and formation of pollen tubes of oil palm. / No Brasil, pesquisas com gr?os de p?len da fam?lia Arecaceae est?o relacionados ? melissopalinologia e palinotaxonomia, sendo escassos aqueles voltados ? fisiologia do p?len. Estudos de biologia reprodutiva relacionados ? poliniza??o s?o de grande import?ncia nas diversas culturas, visto que a partir dos seus resultados pode se obter par?metros a serem utilizados visando o aumento consider?vel da produ??o de plantas cultivadas, bem como no tamanho e na qualidade dos frutos, contribuindo para bons rendimentos econ?micos dos produtores. A germina??o de gr?os de p?len in vitro tamb?m permite verificar seu vigor reprodutivo, sendo importante ferramentas em programas de melhoramento gen?tico de plantas, auxiliando na sele??o de gen?tipos mais eficazes para cruzamentos e forma??o de h?bridos. O cap?tulo um deste trabalho teve como prop?sito avaliar o tipo de meio de cultura e as implica??es da escolha dos micronutrientes que fazem parte da sua composi??o, bem como do tratamento pr?vio das amostras. Foi observado que o p?len de dendezeiro (Elaeis guineensis Jacq.) apresentou aumento nas taxas de germina??o depois de ser desidratado por um per?odo de quatro horas e que o meio de cultura com apenas ?cido b?rico e nitrato de c?lcio, al?m da sacarose como fonte de energia, s?o eficientes para exibir o potencial germinativo. O cap?tulo dois consta da avalia??o de prote?nas glicoconjugadas (lectinas) sobre a germinabilidade pol?nica do dendezeiro. Foram discutidas as intera??es metab?licas desses processos, bem como o papel das lectinas que s?o importantes reguladores sobre a recogni??o e reconhecimento do p?len no pistilo, podendo atuar como fatores de incompatibilidade gen?tica. Foi avaliada a germina??o em meio BCa (boro e c?lcio) com adi??o das lectinas: Lectina de Crotalaria pallida Aiton (CPL), Concanavalina A (ConA) e Jacalina (JAC), em duas concentra??es. Verificou-se aumento das taxas de germina??o na presen?a das lectinas CPL e ConA e inibi??o da germina??o na presen?a da JAC. Os resultados deste trabalho agregam valores informativos sobre a compreens?o da biologia reprodutiva de dendezeiro (Arecaceae) ocorrente na ?Costa do Dend??/Bahia e ampliam as discuss?es sobre os processos que envolvem a germina??o de gr?os de p?len e forma??o dos tubos pol?nicos.

Windows in building façade are vulnerable to blast pressures. When subjected to blast shock waves, glass windows may suffer failures, potentially causing serious injuries and casualties to the building occupants due to the flying glass shards and other projectiles. Protective films and laminated glass are widely used to protect windows against blast loads. These techniques have proven to reduce or prevent hazards associated with glass breakage. The use of steel or strengthened aluminum frames also reduce window blast hazards associated with frame failures. However, such measures are not always sufficient to mitigate the blast hazard if window retention anchors do not have sufficient resistance to blast pressures. Research on blast resistant windows is scarce in the literature. Therefore, a comprehensive research project was undertaken to address the behaviour, analysis, and design of window retention anchors. The research program consisted of combined experimental and analytical components. Three main phases were pursued, comprising of: i) Experimental research using a shock tube as blast simulator, ii) Numerical investigation based on three-dimensional finite element method (FEM) of analysis, and iii) Non-linear dynamic analysis of window systems based on a single-degree-of-freedom (SDOF) simplification. The experimental phase consisted of tests of 23 punched windows mounted on four different types of substrates consisting of structural steel, reinforced concrete, concrete block masonry, and stone masonry. The experimental parameters included window size and aspect ratio, glazing type, protective film thickness, substrate type, as well as the number and pattern of window retention anchors. Two levels of blast pressure-impulse combinations were used as per the recommendations of the U.S General Services Administration (GSA).The numerical phase involved FEM modelling and analysis of selected test windows. The FEM models were first validated against test results. The validated models were then employed to conduct an analytical parametric study. The parameters in this phase consisted of; substrate type, window frame rigidity, anchor fixity level in the substrate, window aspect ratio and size, anchor spacing, and blast pressure-impulse combination. The results demonstrated the significance of design parameters on window response, while also defining anchor force distribution along the window frame. A simplified SDOF method of analysis was developed for window systems, including the effects of anchor flexibility and substrate rigidity on non-linear response. The analysis approach includes the construction of window resistance functions in pre-break and post-break phases of response, where the latter stage of response is dominated by the membrane action of protective film. The analysis leads to the computation of anchor design forces, which have been validated against anchor shear and axial tension forces recorded experimentally. The SDOF analysis is recommended for use in designing blast-resistant window retention anchors on different substrates.

I detta kandidatexamensarbete har syftet varit att undersöka metoder för att forma ett wellpappark, skapat av Arcwise (SCA), till en cylindrisk-, tubformad kartong. Arbete mynnade ut till ett koncept för en resningsmaskin som monterar ihop Arcwisetuben. Resningsmaskinen ska vara en instegsmodell från manuellt arbete till en automatisk produktion. För utveckling av maskinkonceptet tillämpades metoden produktutveckling inom industrin, kapitel 4, enligt boken ”Produktutveckling effektiva metoder för konstruktion och design”.  Ifrån produktutveckling inom industrin tillämpas endast fem av sju faser i detta projekt; förstudie, produktspecificering, konceptutveckling-konceptgenerering, konceptutvärdering och konceptval samt prototyp. Förstudien ledde fram till att sugkoppar och tryckluft var bra metoder för tillämpning vid lyft och förflyttning av arket mellan de olika stationerna. Ett wellpappark deformeras inte plastiskt vid formgivning som exempelvis metall och behöver därför formges från två håll. Maskinkoncepten som tas fram görs med hjälp av en kravspecifikation, mind map och en aktivitetsanalys. Konceptskisserna bedöms med hjälp av Pughs matris. Det vinnande konceptet var en länkarmslösning som slutligen visualiseras i CAD som en prototyp. Projektets syfte uppfylldes genom att Arcwise wellpappark går att forma till en cylindrisk kartong och ett koncept som är redo för tillverkningsanpassning har tagits fram. / The purpose of this project has been to investigate methods for shaping a corrugated sheet, created by Arcwise (SCA), into a cylindrical tube. The work led to a concept of a Corrugated cardboard machine that produces Arcwise tubes. The machine is an entry-level model from manual work to automatic production. The development of the machine concept used is the method of Product development of industry. In the method were five of seven phases used: Feasibility study, product specification, concept development and concept generation, concept evaluation and concept selection and prototype. The feasibility study led to the fact that a suction cup and compressed air were good methods for lifting and moving the sheet between different stations. A corrugated sheet does not deform plastically during forming and therefore needs to be shaped from two directions. The machine concept that is developed are made with help of a requirements specification, mind map and an activity analysis. Pughs matrix were used to evaluate and decide which concept to develop further. The winning concept was a link arm solution that is visualized in CAD as a prototype. The purpose of the project where fulfilled, the Arcwise corrugated board can be shaped into a cylindrical tube and a production concept ready for manufacturing adaptation has been developed.

This diploma thesis deals with a basic description of dynamic and condenser microphone, its performance regarding polar patterns and a type of mechanical construction. It also describes a principle of operation of a triode. The thesis deals with selecting of a suitable type of microprocessor to control microphone preamplifier functions. Last part contains a power supply and microphone preamplifier circuits design using a semiconductor and vacuum tube technology.

Significant maldistribution negatively influences performance of equipment containing dense tube bundles and, moreover, it can cause a wide range of operating issues. This thesis therefore focuses on analysis of fluid flow in complete distribution systems via computational fluid dynamics (CFD). Data obtained from simulations carried out using the software ANSYS Fluent were also statistically analysed. Influence of system arrangement, tube bundle parameters and operating parameters on flow distribution non-uniformity and pressure drop was investigated. According to the results, system arrangement is the crucial differentiating parameter in terms of flow distribution as well as pressure drop. Additionally, data obtained via the classical CFD approach were compared with those yielded by a simplified CFD model for three selected distribution systems. Simplified CFD approach can - given its low computational demand - be utilised in optimization algorithms as well as in the course of the initial stage of equipment design process. Furthermore, this thesis discusses a simulation tool which is based on the simplified CFD approach. Although this tool is still being developed, the results it yields are very promising.

The aim of the thesis is to design and appreciation steel load-bearing structure of motor show. The object is situated in Brno. The Structure consist of tubes and rolling sections. The breadth of construction is 36,5m, lenght 42m and height in the heihest point is 13,2m. The structrure is consists of three parts. Show room, offices and workshop. The height of show room is 20m, offices 8,5m and workshop 8m. The show room consist of arched truss girder. The distance of each cross links is 6 m. Structural design were perfomered by Scia Engineer 2017 and hand computation.

Tato diplomová práce se zaměřuje na modelování proudění tekutiny v paralelních distribučních systémech, kde hraje důležitou roli rovnoměrnost distribuce tekutin. Pro tento účel je vytvořen vlastní CFD kód. Kód je napsán v programovacím jazyce Java a používá ke zlepšení výkonu knihovny třetích stran, které se vyznačují přímým přístupem ke hardwarovým a systémovým prostředkům. Kód se také vyznačuje určitými zjednodušeními, u nichž se očekává, že sníží výpočetní časy. Vliv použitých zjednodušujících opatření je vyhodnocen porovnáním výsledků simulací proudění na několika geometriích s údaji získanými z podrobných modelů CFD. Geometrie použitých svazků trubek se odlišují různými uspořádáními toku a trubek a také různým počtem trubek.

The diploma thesis aims to establish thermo-hydraulic properties of a flexible tube described by its Darcy friction factor and film heat transfer coefficient respectively. A flexible tube (corrugated stainless steel tube) is an easily shapeable stainless steel component used to build various piping connections, in a place of more common copper or plastic made tubes. It can also be used to build heat exchangers thanks to its signature properties. The investigated product is the one developed and manufactured by the Czech company Flexira s.r.o. and sold under the brand name xConnect System. Its thermo-hydraulic properties are established by an experiment, which is based on real utilizations by Laboratory of Energy Intensive Processes in NETME (New Technologies for Mechanical Engineering) Centre at Brno University of Technology. The investigated case is a coil-shaped element serving a purpose of a water-to-water heat exchanger. The text contains a literature survey of the chosen flexible tube and a description of a draft and development of the specific experimental test based off the established theory. The obtained results are then analysed, for the purpose of establishing a functional dependence, which can then be used to calculate a film heat transfer coefficient.

The master thesis deals with the influence of heat treatment and storage time on microstructure and mechanical properties of 26MnB5 steel, which is used in the production of tubular components in the quenched and tempered state. The objective was to increase the plasticity of the steel by the definition of new process parameters of the induction heat treatment line. New tempering diagrams of 26MnB5 steel for two various speeds of the heat treatment line were established and used to determine new tempering temperature and speed of the heat treatment line. Observation of the influence of storage time on mechanical properties of the steel did not reveal that it is liable to ageing.