This paper presents the behaviour and design of axially loaded concrete-filled steel tube circular stub columns. The study was conducted over a wide range of concrete cube strengths ranging from 30 to 110 MPa. The external diameter of the steel tube-to-plate thickness (D/t) ratio ranged from 15 to 80 covering compact steel tube sections. An accurate finite element model was developed to carry out the analysis. Accurate nonlinear material models for confined concrete and steel tubes were used. The column strengths and load¿axial shortening curves were evaluated. The results obtained from the finite element analysis were verified against experimental results. An extensive parametric study was conducted to investigate the effects of different concrete strengths and cross-section geometries on the strength and behaviour of concrete-filled compact steel tube circular stub columns. The column strengths predicted from the finite element analysis were compared with the design strengths calculated using the American, Australian and European specifications. Based on the results of the parametric study, it is found that the design strengths given by the American Specifications and Australian Standards are conservative, while those of the European Code are generally unconservative. Reliability analysis was performed to evaluate the current composite column design rules.

Vacuum-assisted toilets make use of a large pressure difference between the ambient pressure and a vacuum tank to transport waste from the toilet bowl to the septic tank. This process requires 98% less water per flush making it an attractive product for transport vehicles such as airplanes, cruise ships, and trains. Unfortunately, the water savings come at the cost of high noise levels. This thesis investigates the acoustic characteristics of a vacuum-assisted toilet flush and several methods to reduce the radiated noise. Some methods include changing rinse parameters such as rinse pressure, rinse length, and rinse timing, adding structural damping of the bowl to reduce re-radiation, inserting a tube between the bowl and valve that utilizes a larger bend radius and longer tube length than what is currently installed, and modifying the valve. The most effective solution without requiring more water per flush was to insert a tube. The initial peak level was reduced by 16 dB and the steady-vacuum noise was reduced by 5 dB. Evidence of evanescent decay and reduced flow velocity as possible mechanisms for the noise reduction are presented and discussed. Rinse variations show a strong impact of the rinse-tube interaction on the noise reduction. In addition to these techniques, a modified flush plate opening and closing velocity profile is suggested which optimizes the sound generated by the opening and closing of the valve. Finally, a promising dual-valve solution that may take extra coordination of vacuum-assisted toilet manufacturers and airplane/cruise ship/train manufacturers is presented. By placing a secondary valve near the septic tank, the main noise from the valve is significantly reduced.

A theoretical study has been conducted to investigate the effect of flat bars supports on the dynamic response of a heat exchanger U-tube. The tube is modelled using three dimensional, six degrees of freedom per node straight beam finite elements. A new method, the stiffness method, is introduced to compute the impact forces at the supports. It is compared with the previously used external force method. Modal analysis is employed to investigate the modal energy dissipation in the higher modes. Time response of the U-tube is analysed using a Fast Fourier Transform algorithm. The effects of clearance, excitation magnitude, and mode coupling through friction at the supports are investigated. / Thesis / Master of Engineering (ME)

Today, the world faces an energy source transformation that is difficult to grasp. To convert to a green energy society, carbon, oil, and natural gas must faze out as fuels during the upcoming decades. Hydrogen gas has received a lot of attention in recent years regarding the challenges in the energy sector, not only because of its multifunctionality as a fuel but also because it is a great energy carrier. The largest part of the green hydrogen gas produced in the future will be made in locations with great possibilities to produce hydrogen gas from solar energy. This means that a huge amount of this will need to be transported (and stored correctly during transportation) to countries with an increased industrial need for hydrogen but with insufficient production of hydrogen. The report will cover two different ways of transporting hydrogen gas. The first one is intermodal transport of tubes (hydrogen gas) or tanks (cryogenic hydrogen), and the second one is through pipelines. The report will also investigate two different ways of storing hydrogen, as a cryogenic liquid or as a compressed gas. The report will also investigate the production of intermodal commodities for compressed hydrogen gas where a material selection will be made to optimise the possibilities to store and transport hydrogen gas. The material selection analysis showed that a duplex stainless steel was the best material for hydrogen gas tubes. From the result, it is clear that compressed hydrogen gas in tube containers is the cheapest transport method with respect to both Operational Expenses (OpEx) and Capital Investment Expenses (CapEx). / Idag står världen inför en energiomställning med stora hinder. För att ställa om till ett samhälle med grön energi står det klart att kol, olja och naturgas måste fasas ut som bränslen under de kommande decennierna. Vätgas har fått mycket uppmärksamhet under de senaste åren när det gäller utmaningarna inom energisektorn, inte bara på grund av dess multifunktionalitet som bränsle utan också för att det är en utmärkt energibärare. Den största delen av den gröna vätgas som produceras i framtiden kommer att tillverkas på platser med stora möjligheter att producera vätgas från solenergi. Detta innebär att en enorm mängd av detta kommer att behöva transporteras (och lagras korrekt under transporten) till länder med ett ökat industriellt behov av vätgas men med otillräcklig produktion av vätgas. Rapporten kommer att omfatta två olika sätt att transportera vätgas. Det första är intermodal transport av tuber (vätgas) eller tankar (kryogen vätgas), och det andra är genom rörledningar. Rapporten kommer också att undersöka två olika sätt att lagra vätgas, som en kryogen vätska eller som en komprimerad gas. Rapporten kommer också att undersöka produktionen av intermodala råvaror för komprimerad vätgas där ett materialval kommer att göras för att optimera möjligheterna att lagra och transportera vätgas. Materialvalsanalysen visade att duplex rostfritt stål var det bästa materialet för vätgastuber. Av resultatet framgår det tydligt att komprimerad vätgas i rörbehållare är den billigaste transportmetoden med avseende på både Operational Expenses (OpEx) och Capital Investment Expenses (CapEx).

Curtain walls provide exterior façade to modern buildings. When subjected to blast shock waves, curtain walls may suffer significant damage, potentially causing serious injuries and casualties to building occupants. Protective films, laminated glass and strengthening of mullions and transoms are used to protect curtain wall components against blast loads. Limited research is available on blast protection of curtain wall components. On the other hand, connections of curtain wall mullions with the supporting substrate, as well as mullion-transom connections form potentially vulnerable locations under blast loads. Research on these connections is lacking in the literature. Therefore, a comprehensive research project has been undertaken in this thesis to address the behavior, analysis, and design of curtain wall connections, both between the mullions and supporting concrete slabs/beams and the mullions and transoms. The research project consists of three phases: i) Experimental research using the University of Ottawa Shock Tube as blast simulator, ii) Numerical investigation based on three-dimensional finite element method (FEM) using LS-DYNA, and iii) Non-linear dynamic analysis of curtain wall systems based on a single-degree-of-freedom (SDOF) to develop a connection design procedure. The experimental phase consisted of tests of three full-size curtain walls mounted on steel HSS sections of the Shock Tube to investigate mullion-to-transom connections and nine single mullions connected to concrete beams to investigate mullion-to-concrete substrate connection. The single mullions either represented floor-to-floor mullions or continuous mullions over the supporting slab. They were connected to concrete beams (representing floor slabs) by means of brackets, which provided high degree of rotational restraints and full translational restraints or connected through damping materials (springs or HRD rubber pads), which allowed translational movements as they dampened the effects of the shock wave. The numerical investigation involved FEM analysis and modeling of all the test specimens. The first step involved the validation of numerical models against test data. The analysis was then extended to conduct a parametric investigation to cover cases that have not been covered in the experiments. This resulted in the investigation of six different design parameters used in connection design. The numerical outcomes illustrated the importance of blast effects on connection design parameters, support reactions, curtain wall response, force and stress distributions on curtain wall components. The information gathered through experimental and numerical research on connection performance led to the formulation of a connection design procedure. Single-degree-of-freedom (SDOF) dynamic analysis technique was adopted to curtain wall analysis as a tool to compute connection design forces. Both the Uniform Facilities Criteria (UFC) charted solution (manual calculations) and two computer software developed at the University of Ottawa (RC-Blast and CW-Blast) were used to conduct SDOF analysis to validate the procedure against experimental and numerical results before they were recommended as design tools. Finally, the details of connection design are provided for different types of connections.

Cold pilgering is a challenging tube forming process in terms of modeling due to the complexity in kinematic of tools, friction condition and material behavior. The process development has mostly been based on simple formulas and costly full-scale tryouts. The aim in this study is to develop validated Finite element models of cold pilgering to increase the understanding of influence of the process parameters on the produced tubes. In the course of this thesis, three-dimensional mechanical and thermo-mechanical Finite element models of cold pilgering were developed. The commercial code MSC.Marc was used in the simulations. General 3D models are needed to be able to capture asymmetric deformation in cold pilgering. It was found that tool deflections together with elastic deformation of roll dies have considerable influence on the rolling force. Furthermore, the strain rate and temperature effects on the response of the material and thereby on the rolling force were evaluated.

Transient Receptor Potential channels (TRP) are a superfamily of cationic specific ionchannels that are regulated by various stimuli such as temperature, pH, mechanical stress, ligandsand ion concentration. The role of TRP channels in disease states such as autosomal dominantpolycystic kidney disease, cancer metastasis, and developmental defects lend credence to thebelief that they play an important part in epithelial morphogenesis events. The development ofsomites, neural tube closure and migration of neural crest cells to form things such as the faceand heart is a good developmental model for the aforementioned cellular processes. We haveshown that TRP channels can be found in the developing ectoderm, hindbrain, and heart and thatthe inhibition of TRP channels in a developing embryo results in phenotypes suggestingperturbation of cellular remodeling processes. This leads to the question of the specific role ofTRP channels in the epithelial mesenchymal transition and remodeling in developing chickembryos.

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