Pushover analysis of an existing reinforced concrete bridge:Jamboree Road Overcrossing in Irvine, California

The work for the present thesis started in California, during my semester as an exchange student overseas. California is known worldwide for its seismicity and its effort in the earthquake engineering research field. For this reason, I immediately found interesting the Structural Dynamics Professor, Maria Q. Feng's proposal, to work on a pushover analysis of the existing Jamboree Road Overcrossing bridge. Concrete is a popular building material in California, and for the most part, it serves its functions well. However, concrete is inherently brittle and performs poorly during earthquakes if not reinforced properly. The San Fernando Earthquake of 1971 dramatically demonstrated this characteristic. Shortly thereafter, code writers revised the design provisions for new concrete buildings so to provide adequate ductility to resist strong ground shaking. There remain, nonetheless, millions of square feet of non-ductile concrete buildings in California. The purpose of this work is to perform a Pushover Analysis and compare the results with those of a Nonlinear Time-History Analysis of an existing bridge, located in Southern California. The analyses have been executed through the software OpenSees, the Open System for Earthquake Engineering Simulation. The bridge Jamboree Road Overcrossing is classified as a Standard Ordinary Bridge. In fact, the JRO is a typical three-span continuous cast-in-place prestressed post-tension box-girder. The total length of the bridge is 366 ft., and the height of the two bents are respectively 26,41 ft. and 28,41 ft.. Both the Pushover Analysis and the Nonlinear Time-History Analysis require the use of a model that takes into account for the nonlinearities of the system. In fact, in order to execute nonlinear analyses of highway bridges it is essential to incorporate an accurate model of the material behavior. It has been observed that, after the occurrence of destructive earthquakes, one of the most damaged elements on highway bridges is a column. To evaluate the performance of bridge columns during seismic events an adequate model of the column must be incorporated. Part of the work of the present thesis is, in fact, dedicated to the modeling of bents. Different types of nonlinear element have been studied and modeled, with emphasis on the plasticity zone length determination and location. Furthermore, different models for concrete and steel materials have been considered, and the selection of the parameters that define the constitutive laws of the different materials have been accurate. The work is structured into four chapters, to follow a brief overview of the content. The first chapter introduces the concepts related to capacity design, as the actual philosophy of seismic design. Furthermore, nonlinear analyses both static, pushover, and dynamic, time-history, are presented. The final paragraph concludes with a short description on how to determine the seismic demand at a specific site, according to the latest design criteria in California. The second chapter deals with the formulation of force-based finite elements and the issues regarding the objectivity of the response in nonlinear field. Both concentrated and distributed plasticity elements are discussed into detail. The third chapter presents the existing structure, the software used OpenSees, and the modeling assumptions and issues. The creation of the nonlinear model represents a central part in this work. Nonlinear material constitutive laws, for concrete and reinforcing steel, are discussed into detail; as well as the different scenarios employed in the columns modeling. Finally, the results of the pushover analysis are presented in chapter four. Capacity curves are examined for the different model scenarios used, and failure modes of concrete and steel are discussed. Capacity curve is converted into capacity spectrum and intersected with the design spectrum. In the last paragraph, the results of nonlinear time-history analyses are compared to those of pushover analysis.

N-Heterocyclic carbene complexes of silver, rhodium and iron: structures, dynamics and catalysis

The research performed in the framework of this Master Thesis has been directly inspired by the recent work of an organometallic research group led by Professor Maria Cristina Cassani on a topic related to the structures, dynamics and catalytic activity of N-heterocyclic carbene-amide rhodium(I) complexes1. A series of [BocNHCH2CH2ImR]X (R = Me, X = I, 1a’; R = Bz, X = Br, 1b’; R = trityl, X = Cl, 1c’) amide-functionalized imidazolium salts bearing increasingly bulky N-alkyl substituents were synthetized and characterized. Subsequently, these organic precursors were employed in the synthesis of silver(I) complexes as intermediate compounds on a way to rhodium(I) complexes [Rh(NBD)X(NHC)] (NHC = 1-(2-NHBoc-ethyl)-3-R-imidazolin-2-ylidene; X = Cl, R = Me (3a’), R = Bz (3b’), R = trityl (3c’); X = I, R = Me (4a’)). VT NMR studies of these complexes revealed a restricted rotation barriers about the metal-carbene bond. However, while the rotation barriers calculated for the complexes in which R = Me, Bz (3a’,b’ and 4a) matched the experimental values, this was not true in the trityl case 3c’, where the experimental value was very similar to that obtained for compound 3b’ and much smaller with respect to the calculated one. In addition, the energy barrier derived for 3c’ from line shape simulation showed a strong dependence on the temperature, while the barriers measured for 3a’,b’ did not show this effect. In view of these results and in order to establish the reasons for the previously found inconsistency between calculated and experimental thermodynamic data, the first objective of this master thesis was the preparation of a series of rhodium(I) complexes [Rh(NBD)X(NHC)] (NHC = 1-benzyl-3-R-imidazolin-2-ylidene; X = Cl, R = Me, Bz, trityl, tBu), containing the benzyl substituent as a chiral probe, followed by full characterization. The second objective of this work was to investigate the catalytic activity of the new rhodium compounds in the hydrosilylation of terminal alkynes for comparison purposes with the reported complexes. Another purpose of this work was to employ the prepared N-heterocyclic ligands in the synthesis of iron(II)-NHC complexes.

A LES study of a modified Ahmed body geometry

A numerical study using Large Eddy Simulation Coherent Structure Model (LES-CSM), of the flow around a simplified Ahmed body, has been done in this work of thesis. The models used are two salient geometries from the experimental investigation performed in [1], and consist, in particular, in two notch-back body geometries. Six simulation are carried out in total, changing Reynolds number and back-light angle of the model’s rear part. The Reynolds numbers used, based on the height of the models and the free stream velocity, are Re = 10000, Re = 30000 and Re = 50000. The back-light angles of the slanted surface with respect to the horizontal roof surface, that characterizes the vehicle, are taken as B = 31.8◦ and B = 42◦ respectively. The experimental results in [1] have shown that, depending on the parameter B, asymmetric and symmetric averaged flow over the back-light and in the wake for a symmetric geometry can be observed. The aims of the present work of master thesis are principally two. The first aim is to investigate and confirm the influence of the parameter B on the presence of the asymmetry of the averaged flow, and confirm the features described in the experimental results. The second important aspect is to investigate and observe the influence of the second variable, the Reynolds number, in the developing of the asymmetric flow itself. The results have shown the presence of the mentioned asymmetry as well as an influence of the Reynolds number on it.

Feeding behaviour of the Corydoradinae

The evolution of a sub-family of south-american freshwater catfishes has created a great diversification of its representants into a huge number of species, usually members of characteristic mimicry communities. After the work of Alexandrou (Alexandrou, 2011) on the phylogeny of the group that discovered the existence of more deep divisions, from the taxonomic point of view, of the sub-family, even from the ecological point of view, I tried to reconfirm these statements from the ethological point of view, settling watching and recording sessions and an experiment that could show their interactions on the environment by observing their substrate mixing action.

Origin of cold gas and dust in massive elliptical galaxies

The recent availability of multi-wavelength data revealed the presence of large reservoirs of warm and cold gas and dust in the innermost regions of the majority of massive elliptical galaxies. To prove an internal origin of cold and warm gas, the investigation of the spatially distributed cooling process which occurs because of non-linear density perturbations and subsequent thermal instabilities is of crucial importance. The first goal of this work of thesis is to investigate the internal origin of warm and cold phases. Numerical simulations are the powerful tool of analysis. The way in which a spatially distributed cooling process originates has been examined and the off-centre amount of gas mass which cools when different and differently characterized AGN feedback mechanisms operate has been quantified. This thesis demonstrates that the aforementioned non-linear density perturbations originate and develop from AGN feedback mechanisms in a natural fashion. An internal origin of the warm phase from the once hot gas is shown to be possible. Computed velocity dispersions of ionized and hot gas are similar. The cold gas as well can originate from the cooling process: indeed, it has been estimated that the surrounding stellar radiation, which is one of the most feasible sources of ionization of the warm gas, does not manage to keep ionized all the gas at 10^4 K. Therefore, cooled gas does undergo a further cooling which can lead the warm phase to lower temperatures. However, the gas which has cooled from the hot phase is expected to be dustless; nonetheless, a large fraction of early type galaxies has detectable dust in their cores, both concentrated in filamentary and disky structures and spread over larger regions. Therefore a regularly rotating disk of cold and dusty gas has been included in the simulations. A new quantitative investigation of the spatially distributed cooling process has therefore been essential: the contribution of the included amount of dust which is embedded in the cold gas does have a role in promoting and enhancing the cooling. The fate of dust which was at first embedded in cold gas has been investigated. The role of AGN feedback mechanisms in dragging (if able) cold and dusty gas from the core of massive ellipticals up to large radii has been studied.

Multicentre study for a robust protocol in single-voxel spectroscopy: quantification of MRS signals by time-domain fitting algorithms

Magnetic Resonance Spectroscopy (MRS) is an advanced clinical and research application which guarantees a specific biochemical and metabolic characterization of tissues by the detection and quantification of key metabolites for diagnosis and disease staging. The "Associazione Italiana di Fisica Medica (AIFM)" has promoted the activity of the "Interconfronto di spettroscopia in RM" working group. The purpose of the study is to compare and analyze results obtained by perfoming MRS on scanners of different manufacturing in order to compile a robust protocol for spectroscopic examinations in clinical routines. This thesis takes part into this project by using the GE Signa HDxt 1.5 T at the Pavillion no. 11 of the S.Orsola-Malpighi hospital in Bologna. The spectral analyses have been performed with the jMRUI package, which includes a wide range of preprocessing and quantification algorithms for signal analysis in the time domain. After the quality assurance on the scanner with standard and innovative methods, both spectra with and without suppression of the water peak have been acquired on the GE test phantom. The comparison of the ratios of the metabolite amplitudes over Creatine computed by the workstation software, which works on the frequencies, and jMRUI shows good agreement, suggesting that quantifications in both domains may lead to consistent results. The characterization of an in-house phantom provided by the working group has achieved its goal of assessing the solution content and the metabolite concentrations with good accuracy. The goodness of the experimental procedure and data analysis has been demonstrated by the correct estimation of the T2 of water, the observed biexponential relaxation curve of Creatine and the correct TE value at which the modulation by J coupling causes the Lactate doublet to be inverted in the spectrum. The work of this thesis has demonstrated that it is possible to perform measurements and establish protocols for data analysis, based on the physical principles of NMR, which are able to provide robust values for the spectral parameters of clinical use.

Synthesis of novel cobalt and iron complexes for sustainable catalytic hydrogenations

Aim of the present work of thesis is to synthesize new non-noble metal based complexes to be employ in redox reactions by a metal-ligand cooperative mechanism. The need of replacing toxic and expensive precious metal complexes with more available and benign metals, has led to the development of new compounds based on cobalt and iron, which are the metals investigated in this study. A carbonyl-tetrahydroborato-bis[(2-diisopropylphosphino)ethyl]amine-cobalt complex bearing a PNP-type ligand is synthesized by a three-step route. Optimization attempt of reaction route were assessed in order to lowering reaction times and solvent waste. New cobalt complex has been tested in esters hydrogenation as well as in acceptorless dehydrogenative coupling of ethanol. Other varieties of substrates were also tested in order to evaluate any possible applications. Concerning iron complex, dicarbonyl-(η4-3,4-bis(4-methoxyphenyl)-2,5-diphenylcyclopenta-2,4-dienone)(1,3-dimethyl-ilidene)iron is synthesized by a three steps route, involving transmetallation of a silver complex, derived from an imidazolium salt, to iron complex. In order to avoid solvent waste, optimization is assessed. Studies were performed to assess activity of triscarbonyl iron precursor toward imidazolium salt and silver complexes.

Feedback linearization of antagonistically actuated variable stiffness joints with twisted string actuators

The work of this thesis is on the implementation of a variable stiffness joint antagonistically actuated by a couple of twisted-string actuator (TSA). This type of joint is possible to be applied in the field of robotics, like UB Hand IV (the anthropomorphic robotic hand developed by University of Bologna). The purposes of the activities are to build the joint dynamic model and simultaneously control the position and stiffness. Three different control approaches (Feedback linearization, PID, PID+Feedforward) are proposed and validated in simulation. To improve the properties of joint stiffness, a joint with elastic element is taken into account and discussed. To the end, the experimental setup that has been developed for the experimental validation of the proposed control approaches.

When Beauty Goes to Sleep: an analysis of the symbolism behind the sleeping beauty tale

Approaching the world of the fairy tale as an adult, one soon realizes that things are not what they once seemed during story time in bed. Something that once appeared so innocent and simple can become rather complex when digging into its origin. A kiss, for example, can mean something else entirely. I can clearly remember my sister, who is ten years older than I am, telling me that the fairy tales I was told had a mysterious hidden meaning I could not understand. I was probably 9 or 10 when she told me that the story of Sleeping Beauty, which I used to love so much in Disney’s rendering, was nothing more than the story of an adolescent girl, with all the necessary steps needed to become a woman, the bleeding of menstruation and the sexual awakening - even though she did not really put it in these terms. This shocking news troubled me for a while, so much so that I haven’t watched that movie since. But in reality it was not fear that my sister had implanted in me: it was curiosity, the feeling that I was missing something terribly important behind the words and images. But it was not until last year during my semester abroad in Germany, where I had the chance to take a very interesting English literature seminar, that I fully understood what I had been looking for all these years. Thanks to what I learned from the work of Bruno Bettelheim, Jack Zipes, Vladimir Propp, and many other authors that wrote extensively about the subject, I feel I finally have the right tools to really get to know this fairy tale. But what I also know now is that the message behind fairy tales is not to be searched for behind only one version: on the contrary, since they come from oral traditions and their form was slowly shaped by centuries of recountals and retellings, the more one digs, the more complete the understanding of the tale will be. I will therefore look for Sleeping Beauty’s hidden meaning by looking for the reason why it did stick so consistently throughout time. To achieve this goal, I have organized my analysis in three chapters: in the first chapter, I will analyze the first known literary version of the tale, the French Perceforest, and then compare it with the following Italian version, Basile’s Sun, Moon, and Talia; in the second chapter, I will focus on the most famous and by now classical literary versions of Sleeping Beauty, La Belle Au Bois Dormant, written by the Frenchman, Perrault, and the German Dornröschen, recorded by the Brothers Grimm’s; finally, in the last chapter, I will analyze Almodovar’s film Talk to Her as a modern rewriting of this tale, which after a closer look, appears closely related to the earliest version of the story, Perceforest.

The creation and use of an international reference glossary specific for horror role-playing games

This thesis focuses on the technical approach to the translation of the Italian horror role-playing game Sine Requie into English. It aims to prove that both the role-playing and horror aspects of the genre are important to convey an enjoyable experience to the players, and that it is possible to create and international reference glossary to better translate the horror genre itself. Following a brief introduction of the history of role-playing games (RPGs), we will look at the RPG technical vocabulary in Sine Requie, and analyze which of these elements can be translated following the great models of the history of role-playing games. A brief introduction will follow regsrding the horror genre and its core characteristics based on the work of worldwide famous horror writer H.P. Lovecraft. Lastly, a description on how the international reference glossary for the horror genre was created will be presented along with a few examples of its practical use.

Dynamics of inorganic carbon and carbonate saturation in the Gulf of Cádiz (SW Spain)

The study of inorganic carbon chemistry of the coastal ocean is conducted in the Gulf of Cádiz (GoC). Here we describe observations obtained during 4 sampling cruises in March, June, September and November 2015. The primary data set consists of state-of-the-art measurements of the keystone parameters of the marine CO2 system: Total Alkalinity (TA), pH, dissolved inorganic carbon (DIC). We have then calculated aragonite and calcite saturation state. The distribution of inorganic carbon system parameters in the north eastern shelf of the Gulf of Cádiz showed temporal and spatial variability. River input, mixing, primary production, respiration and remineralization were factors that controlled such distributions. Data related to carbonate saturation of calcite and aragonite reveal the occurrence of a supersaturated water; in any case, both species increased with distance and decreased with depth. The carbon system parameters present a different behaviour close to the coast to offshore ad at deeper water. In this area six water masses are clearly identified by their different chemical properties: Surface Atlantic Water, North Atlantic Central Water (NACW) and Mediterranean Water (MOW). Moreover, with this work the measurement of calcium in seawater is optimize, allowing a better quantification for future work of the saturation state of CaCO3.