Oil well blow outs are investigated to determine methods to quickly and accurately respond to an emergency situation. Flow rate is needed to guide containment and dispersal operations. The Stratified Integral Multiphase Plume, SIMP, model was used to investigate the range of initial conditions available to integral modeling. Sensitivity to initial conditions is modest, but without experimental data at the appropriate scale the most accurate condition is unable to be determined. Flow rates are difficult to directly measure in blow out situations, so another method must be determined; therefore, sensitivity of several parameters to flow rate was also evaluated. Methane concentration in the first intrusion can be used in conjunction with velocity and trap height measurements to determine flow rate using an integral model. Plume width and temperature were determined to have little sensitivity. Separately, a containment dome was tested in the laboratory to determine if a full scale dome can be used to contain an oil leak in the field. The dome was found to have satisfactory entrapment in the designed position.

The Square Kilometre Array (SKA) is a multibillion and a multinational science project to build the world’s largest and most sensitive radio telescope. For a very large field of view, the combined collecting area would be one square kilometre (or 1, 000, 000 square metre) and spread over more than 3,000 km wide which will require a massive count of antennas (thousands). Each of the antennas contains hundreds of low noise amplifier (LNA) circuits. The antenna arrays are divided into low, medium and high operational frequencies and located at different positions to boost up the telescope’s scanning sensitivity.The objective of this work was to develop and fabricate fully on-chip LNA circuits to meet the stringent requirements for the mid-frequency array from 0.4 GHz to 1.4 GHz of the SKA radio astronomy telescope using Monolithic Microwave Integrated Circuit technology (MMIC). Due to the number of LNA reaching figures of millions, the fabricated circuits were designed with the consideration for low cost fabrication and high reliability in the receiver chain. Therefore, a relaxed optical lithography with Lg = 1 µm was adopted for a high yield fabrication process.Towards the fulfilment of the device’s low noise characteristics, a large number of device designs, fabrication and characterisation of InGaAs/InAlAs/InP pHEMTs were undertaken. These include optimisations at each critical fabrication steps. The device’s high breakdown and very low gate leakage characteristics were further improved by a combination of judicious epitaxial growth and manipulation of materials’ energy gaps. An attempt to increase the device breakdown voltage was also employed by incorporating Field Plate structure at the gate terminal. This yielded the devices with improvements in the breakdown voltage up to 15 V and very low gate leakage of 1 µA/mm, in addition to high transconductance (gm) characteristic. Fully integrated double stage LNA had measured NF varying from 1.2 dB to 1.6 dB from 0.4 GHz to 1.4 GHz, compared with a slightly lower NF obtained from simulation (0.8 dB to 1.1 dB) across the same frequency band.These are amongst the attractive device properties for the implementation of a fully on-chip MMIC LNA circuits demonstrated in this work. The lower circuit’s low noise characteristic has been demonstrated using large gate width geometry pHEMTs, where the system’s noise resistance (Rn) has successfully reduced to a few ohms. The work reported here should facilitate the successful implementation of rugged low noise amplifiers as required by SKA receivers.

Master's thesis includes designing of exhibition pavilon on a circular platform with a diameter of 35m. The pavilon is designed as a schwedler circular dome. The construction is designed as a ball and is made of tubes. Pavilon includes designing of floors and stairs bearing system that is also made of steel.

Master's thesis addresses the design and assessment of the load bearing structure of the shopping gallery. The building is designed as a three-storey rectangular plan with a flat roof. The structure is composed of steel frames and composite steel and concrete slabs. There are proposed two possible solutions - variant with a flat roof and direct central gallery, a reinforced rigid steel frames and a variant with a cupola roofed circular inner atrium, solidified with rods.

The master's thesis deals with a project of the steel structure of a residential building. The building is thought like sevenfloor balcony-access house. The access balcony is situated in atrium in the middle of the building, which is roofed with a shell dome. The regular hexagon creates a ground plan of each floor. Every floor is turned 30 degrees compared to the next floors. The longest cross dimension is 43 m (axial). The height of the building is 30,4 m (including copula envelope). The final structure is chosen on the basis of optimization of the structural variants. The climatic load angle structure falls into the locality of the town Brno. The vertical supporting structure is made from steel-concrete accoupled circular section columns. The floor structure is designed from the steel rolled section I and H. These support assembly of a horizontal structure. Some joists and girder are designed like accoupled with a concrete floor slab. The copula above atrium is made from glue laminated timber ribs. Infill rods are from steel tube. The top ring of copula is designed from the rolled section UPE.

The aim of this diploma thesis is a design of the multy-storey steel structure with a wooden dome structure of the shopping centre in city of Banská Bystrica, Slovakia. Minimum build-up area is 2 000m2. Minimum number of storeys is set at 2. Steel structure is composed as a frame construction with composite steel-concrete ceilings. Building has 2 storeys at all. Wooden structure of dome is composed by glue laminated curved beams. The structural design and analysis is performed by software SCIA Engineer 15.

No description available.

With the newly deployed fifth-generation telecommunications system and upcoming sixth-generation, high-gain antennas with hemispherical scanning capabilities are of high interest. Phased array antennas allow for fast scanning capabilities with electronic beam-steering. In an effort to reduce the number of antenna elements while maintaining the antenna aperture size, the element spacing is increased. However sparse arrays introduce grating lobes in the radiation pattern. An interesting solution to reduce the grating lobes is to integrate a lens with the array. Further, simulating the radiation pattern with a ray-tracing algorithm and the geometrical optics approximation makes for fast simulation times. The presented ray-tracing algorithm in this work speeds up the simulation by 43 times compared to a two-dimensional full-wave simulation. To model the full radiation pattern the rays are shot out from a single point across a set angular space. To emulate an element pattern the rays are excited with a set amplitude distribution. Here, two different methods of obtaining the amplitude are presented and compared to a two-dimensional full-wave COMSOL model. The lens is made from a dielectric, constructed from the conics equation with applied conformal matching layers. The ray path and phase distribution are calculated with Snell's law, the amplitude distribution at the lens aperture is calculated through the ray tube theory, and the radiation pattern with the Kirchhoff Diffraction formula. To optimize the lens shape and an array offset, the ray-tracing algorithm is coupled with a Particle Swarm Optimization algorithm. Two different arrays are used in this thesis, the first constructed from open-ended waveguides and the second using sub-arrays of the same waveguides. The optimized lens for the first array shows that a grating lobe suppression between 1.1-2.0 dB is achievable with a main lobe reduction between 0.2-0.3 dB for scanning to -20 degrees. For the array with sub-arrays, the main lobe suppression is between 0.3-0.9 dB, with a grating lobe suppression of up to 4.0 dB. / Med det nyligen lanserade femte generationens telekommunikationssystem och den kommande sjätte generationen är högförstärkningsantenner med halvsfäriska skanningsmöjligheter av stort intresse. Fasade array-antenner möjliggör snabb skanningskapacitet med elektronisk strålstyrning. I ett försök att minska antalet antennelement samtidigt som antennöppningens storlek bibehålls, ökas elementavståndet. Men glesa arrayer introducerar gallerlober i strålningsmönstret. En intressant lösning för att minska gallerloberna är att integrera en lins med arrayen. Vidare, simulering av strålningsmönstret med en strålspårningsalgoritm och den geometriska optiska approximationen ger snabba simuleringstider. Den presenterade strålspårningsalgoritmen i detta arbete snabbar upp simuleringen med 43 gånger jämfört med en tvådimensionell helvågssimulering. För att modellera hela strålningsmönstret skjuts strålarna ut från en enda punkt över ett fast vinkelutrymme. För att efterlikna ett elementmönster exciteras strålarna med en inställd amplitudfördelning. Här presenteras två olika metoder för att erhålla amplituden och jämförs med en tvådimensionell fullvågs-COMSOL-modell. Linsen är gjord av ett dielektrika konstruerat från koniska ekvationen med applicerade konforma matchande lager. Strålvägen och fasfördelningen beräknas med Snell-lagen, amplitudfördelningen vid linsöppningen beräknas genom strålrörsteorin och strålningsmönstret med Kirchhoff-diffraktionsformeln. För att optimera linsformen och en arrayförskjutning är strålspårningsalgoritmen kopplad med en Particle Swarm algoritm. Två olika arrayer används i denna avhandling, den första konstruerad av vågledare med öppen ände och den andra med hjälp av sub-arrayer av samma vågledare. Den optimerade linsen för den första arrayen visar att en gallerlobsundertryckning mellan 1,1-2,0 dB kan uppnås med en huvudlobsreduktion mellan 0,2-0,3 dB för skanning till -20 grader. För arrayen med sub-arrayer är undertryckningen av huvudloben mellan 0,3-0,9 dB, med en gallerlobundertryckning på upp till 4,0 dB.

No description available.

No description available.