Shear behavior of reinforced concrete slabs under concentrated load: an investigation through Sequentially Linear Analysis

ABSTRACT (italiano) Con crescente attenzione riguardo al problema della sicurezza di ponti e viadotti esistenti nei Paesi Bassi, lo scopo della presente tesi è quello di studiare, mediante la modellazione con Elementi Finiti ed il continuo confronto con risultati sperimentali, la risposta in esercizio di elementi che compongono infrastrutture del genere, ovvero lastre in calcestruzzo armato sollecitate da carichi concentrati. Tali elementi sono caratterizzati da un comportamento ed una crisi per taglio, la cui modellazione è, da un punto di vista computazionale, una sfida piuttosto ardua, a causa del loro comportamento fragile combinato a vari effetti tridimensionali. La tesi è incentrata sull'utilizzo della Sequentially Linear Analysis (SLA), un metodo di soluzione agli Elementi Finiti alternativo rispetto ai classici approcci incrementali e iterativi. Il vantaggio della SLA è quello di evitare i ben noti problemi di convergenza tipici delle analisi non lineari, specificando direttamente l'incremento di danno sull'elemento finito, attraverso la riduzione di rigidezze e resistenze nel particolare elemento finito, invece dell'incremento di carico o di spostamento. Il confronto tra i risultati di due prove di laboratorio su lastre in calcestruzzo armato e quelli della SLA ha dimostrato in entrambi i casi la robustezza del metodo, in termini di accuratezza dei diagrammi carico-spostamento, di distribuzione di tensioni e deformazioni e di rappresentazione del quadro fessurativo e dei meccanismi di crisi per taglio. Diverse variazioni dei più importanti parametri del modello sono state eseguite, evidenziando la forte incidenza sulle soluzioni dell'energia di frattura e del modello scelto per la riduzione del modulo elastico trasversale. Infine è stato effettuato un paragone tra la SLA ed il metodo non lineare di Newton-Raphson, il quale mostra la maggiore affidabilità della SLA nella valutazione di carichi e spostamenti ultimi insieme ad una significativa riduzione dei tempi computazionali. ABSTRACT (english) With increasing attention to the assessment of safety in existing dutch bridges and viaducts, the aim of the present thesis is to study, through the Finite Element modeling method and the continuous comparison with experimental results, the real response of elements that compose these infrastructures, i.e. reinforced concrete slabs subjected to concentrated loads. These elements are characterized by shear behavior and crisis, whose modeling is, from a computational point of view, a hard challenge, due to their brittle behavior combined with various 3D effects. The thesis is focused on the use of Sequentially Linear Analysis (SLA), an alternative solution technique to classical non linear Finite Element analyses that are based on incremental and iterative approaches. The advantage of SLA is to avoid the well-known convergence problems of non linear analyses by directly specifying a damage increment, in terms of a reduction of stiffness and strength in the particular finite element, instead of a load or displacement increment. The comparison between the results of two laboratory tests on reinforced concrete slabs and those obtained by SLA has shown in both the cases the robustness of the method, in terms of accuracy of load-displacements diagrams, of the distribution of stress and strain and of the representation of the cracking pattern and of the shear failure mechanisms. Different variations of the most important parameters have been performed, pointing out the strong incidence on the solutions of the fracture energy and of the chosen shear retention model. At last a confrontation between SLA and the non linear Newton-Raphson method has been executed, showing the better reliability of the SLA in the evaluation of the ultimate loads and displacements, together with a significant reduction of computational times.

Model predictive flight control systems for rotorcraft UAS

Constraints are widely present in the flight control problems: actuators saturations or flight envelope limitations are only some examples of that. The ability of Model Predictive Control (MPC) of dealing with the constraints joined with the increased computational power of modern calculators makes this approach attractive also for fast dynamics systems such as agile air vehicles. This PhD thesis presents the results, achieved at the Aerospace Engineering Department of the University of Bologna in collaboration with the Dutch National Aerospace Laboratories (NLR), concerning the development of a model predictive control system for small scale rotorcraft UAS. Several different predictive architectures have been evaluated and tested by means of simulation, as a result of this analysis the most promising one has been used to implement three different control systems: a Stability and Control Augmentation System, a trajectory tracking and a path following system. The systems have been compared with a corresponding baseline controller and showed several advantages in terms of performance, stability and robustness.

Retorica e mito in Giambattista Vico

The purpose of this thesis is to show that Vico had the constant aim, remained unaltered in time, to support the usefulness of Rhetoric. The awareness of the strength acquired by the “anti-rhetorical” movements, particularly by the Cartesians and the Logicians from Port-Royal, obliged Vico to elaborate some strategies and counter-moves that, little by little, became more and more complex and refined, till they inspired his main work, The New Science. By taking into consideration the most significant aspects of Vico’s speculation (topic, tropes, the formation of language, the development of human thought, the new conception of philology ), this work shows that they are part of a strategy worked out by the Neapolitan philosopher, in order to demonstrate the validity, the usefulness and the modernity of Rhetoric. Every aspect of Vico’s thought reaches its peak when Vico formulates his theory about myths, which he interprets as an expression of the primitive man’s necessities and demands. The point of view expressed by this doctorate thesis emphasizes that, despite the inevitable modifications that have taken place through the centuries, Vico’s thought keeps its substantial unity. So those subjects that critical literature tends to separate are, in reality, linked and unified.

Willem de Sitter in Leiden - ein Kapitel in der Rezeptionsgeschichte der Relativitätstheorien

Der niederländische Astronom Willem de Sitter ist bekannt für seine inzwischen berühmte Kontroverse mit Einstein von 1916 bis 1918, worin die relativistische Kosmologie begründet wurde. In diesem Kontext wird sein Name mit dem von ihm geschaffenen kosmologischen Modell verbunden, welches er als Gegenbeispiel zu Einsteins physikalischer Intuition schuf. Obwohl diese Debatte schon in wissenschaftshistorischen Arbeiten analysiert wurde, hat de Sitters Rolle in der Rezeption und dem Verbreiten der allgemeinen Relativitätstheorie bislang in der Hauptrichtung der Einstein-Studien noch nicht die ihr zustehende Aufmerksamkeit erhalten. Die vorliegende Untersuchung zielt darauf ab, seine zentrale Wichtigkeit für die Forschung zur ART innerhalb der Leidener Community aufzuzeigen. Wie Eddington war de Sitter einer der wenigen Astronomen, die sowohl hinreichende Ausbildung als auch nötige Interessen vereinten, um zum einen die spezielle und zum anderen die allgemeine Relativitätstheorie zu verfolgen. Er befasste sich zunächst 1911 mit dem Relativitätsprinzip (Einsteins erstes Postulat der SRT); zwei Jahre später fand er einen Nachweis für die Konstanz der Lichtgeschwindigkeit (Einsteins zweites Postulat). De Sitters Interesse an Gravitationstheorien reicht sogar noch weiter zurück und lässt sich bis 1908 zurückverfolgen. Überdies verfolgte er Einsteins Versuche, einen feldtheoretischen Ansatz für die Gravitation zu konstruieren, inklusive der kontroversen Einstein-Grossmann Theorie von 1913. Diese Umstände zeigen deutlich, dass de Sitters bekannteres Werk zur ART eine Konsequenz seiner vorausgegangenen Forschungen war und kein Resultat einer plötzlichen, erst 1916 einsetzenden Beschäftigung mit Einsteins Relativitätstheorie.

Quadri di sintomi. Teoria della immagini, storia dell'arte e scienze umane in medicina

Lo studio analizza il modo in cui la storia dell’arte e la visual culture vengono utilizzate all’interno delle medical humanities, e cerca di suggerire un metodo più utile rispetto a quelli fin qui proposti. Lo scritto è organizzato in due parti. Nella prima parte sono analizzate alcune teorie e pratiche delle scienze umane in medicina. In particolare, ci concentriamo sulla medicina narrativa e sugli approcci con cui la storia dell’arte viene inclusa nella maggioranza dei programmi di medical humanities. Dopodiché, proponiamo di riconsiderare questi metodi e di implementare il ruolo di un pensiero storico e visivo all’interno di tali insegnamenti. Nella seconda parte, alla luce di quanto emerso nella prima, ci dedichiamo a uno studio di caso: la rappresentazione della melanconia amorosa, o mal d’amore, in una serie di dipinti olandesi del Secolo d’Oro. Colleghiamo queste opere a trattati medico-filosofici dell’epoca che permettano di inquadrare il mal d’amore in un contesto storico; in seguito, analizziamo alcune interpretazioni fornite da studiosi e storici dell’arte a noi contemporanei. In particolare, esaminiamo lo studio pionieristico di Henry Meige, pubblicato sulla “Nouvelle iconographie de la Salpêtrière” nel 1899, da cui emerge la possibilità di un confronto critico sia con le posizioni iconodiagnostiche di Charcot e Richer sia con quelle della prima psicoanalisi.

Erasmo come Ercole nell'adagio Herculei labores

Il lavoro consiste nella traduzione dell’adagio 2001, Herculei labores con commento delle righe 1-116, che comprendono il racconto della fatica di Ercole contro l’idra di Lerna e le interpretazioni che Erasmo ne fornisce per introdurre la filologia come impresa erculea in chiave autobiografica. L’introduzione ha lo scopo di presentare una sintesi degli elementi notevoli del commento e alcune osservazioni sull’autorappresentazione di sé dell’umanista. Erasmo fa dell’identificazione con Ercole un topos della propria descrizione in chiave ironica, ma si propone anche come emulo di Girolamo, di cui cura l’edizione delle lettere. Questo lavoro prende in considerazione infine il ritratto di Erasmo dipinto da Holbein e custodito a Longford Castle in relazione al testo dell’adagio, al quale allude con la scritta in primo piano, ΗΡΑΚΛΕΙΟΙ ΠΟΝΟΙ.

Obsessed With Work: A multi-causal and multi-rater approach to workaholism

Workaholism is defined as the combination of two underlying dimensions: working excessively and working compulsively. The present thesis aims at achieving the following purposes: 1) to test whether the interaction between environmental and personal antecedents may enhance workaholism; 2) to develop a questionnaire aimed to assess overwork climate in the workplace; 3) to contrast focal employees’ and coworkers’ perceptions of employees’ workaholism and engagement. Concerning the first purpose, the interaction between overwork climate and person characteristics (achievement motivation, perfectionism, conscientiousness, self-efficacy) was explored on a sample of 333 Dutch employees. The results of moderated regression analyses showed that the interaction between overwork climate and person characteristics is related to workaholism. The second purpose was pursued with two interrelated studies. In Study 1 the Overwork Climate Scale (OWCS) was developed and tested using a principal component analysis (N = 395) and a confirmatory factor analysis (N = 396). Two overwork climate dimensions were distinguished, overwork endorsement and lacking overwork rewards. In Study 2 the total sample (N = 791) was used to explore the association of overwork climate with two types of working hard: work engagement and workaholism. Lacking overwork rewards was negatively associated with engagement, whereas overwork endorsement showed a positive association with workaholism. Concerning the third purpose, using a sample of 73 dyads composed by focal employees and their coworkers, a multitrait-multimethod matrix and a correlated trait-correlated method model, i.e. the CT-C(M–1) model, were examined. Our results showed a considerable agreement between raters on focal employees' engagement and workaholism. In contrast, we observed a significant difference concerning the cognitive dimension of workaholism, working compulsively. Moreover, we provided further evidence for the discriminant validity between engagement and workaholism. Overall, workaholism appears as a negative work-related state that could be better explained by assuming a multi-causal and multi-rater approach.

Das neue digitale ‚Shakespeare-Bildarchiv Oppel-Hammerschmidt‘ an der Universitätsbibliothek Mainz : Reden und Beiträge anlässlich seiner öffentlichen Vorstellung am 17. November 2008 an der Johannes Gutenberg-Universität Mainz

On the basis of illustrations of Shakespeare's Hamlet, the new digital 'Oppel-Hammerschmidt Shakespeare Illustration Archive' at the Mainz University Library - together with a lavishly-constructed and multiply-linked Web interface version - was presented to the public on 17 November 2008. This e-book, edited by Andreas Anderhub and Hildegard Hammerschmidt-Hummel, contains the speeches and presentations given on the occasion of the opening ceremony of the electronic archive. The collection of the new archive, published here for the first time, holds about 3,500 images and is part of the only Shakespeare illustration archive in the world. The Shakespeare Illustration Archive was founded in 1946 by the internationally acclaimed Shakespeare and Goethe scholar, Prof. Horst Oppel. This part of the archive was donated to the Mainz University Library on condition that its holdings be digitalised and made available to the public. The collection has been named 'The Oppel-Hammerschmidt Shakespeare Illustration Archive' in accordance with the terms of the Agreement of Donation of 9, 15, and 16 September 2005, and honouring the 16 March 1988 Delegation of Authority and Declaration of Intent by Frau Ingeborg Oppel, Prof. Oppel's widow and legal assignee. Vice-President Prof. Jürgen Oldenstein opened the proceedings by noting that 2008 had been a good year for international Shakespeare scholarship. For, in London, the site of the 'Theatre' in Shoreditch, where Shakespeare's company performed, had been unearthed, and in Mainz the Shakespeare Archive had gone online with thousands of illustrations. The Dean of the Faculty of Philosophy and Philology, Prof. Mechthild Dreyer, who mentioned that she herself had long been successfully employing interdisciplinary research methods, took particular pleasure in the transdisciplinary approach to research resolutely pursued by Prof. Hammerschmidt-Hummel. Prof. Clemens Zintzen (Cologne), former President of the Mainz Academy of Literature and Sciences, recalled highlights from the more than sixty-year-long history of the Shakespeare Illustration Archive. Prof. Kurt Otten (Heidelberg and Cambridge) drew an impressive portrait of Horst Oppel's personality as an academic and praised his influential books on Goethe and Shakespeare. He pointed out that Oppel's Shakespeare Illustration Archive, the basis for many a dissertation, had enjoyed great popularity around the world. Prof. Otten also delineated the academic career of Prof. Hammerschmidt-Hummel and her new findings regarding Shakespeare's time, life and work. Prof. Rüdiger Ahrens OBE (Würzburg) drew attention to Prof. Hammerschmidt-Hummel's research results, directly or indirectly arising out of her work on the Shakespeare Illustration Archive. This research had centred on proving the authenticity of four visual representations of Shakespeare (the Chandos and Flower portraits, the Davenant bust and the Darmstadt Shakespeare death mask); solving the mystery around Shakespeare's 'Dark Lady'; and establishing the dramatist's Catholic religion. Prof. Hammerschmidt-Hummel reported on her 'Shakespeare Illustration' project, describing the nature, dimensions and significance of the Archive's pictorial material, which relates to all of Shakespeare's plays and stretches over five centuries. She explained that the digital 'Oppel-Hammerschmidt Illustration Archive' was an addition to the three-volume edition she had compiled, authored and edited for publication in 2003. Unlike the print version, however, the digital collection had only been partly editorially prepared. It represented source material and a basis for further work. Hammerschmidt-Hummel expressed her thanks to the Head of the Central University Library, Dr Andreas Anderhub, for his untiring commitment. After the initial donation had been made, he had entered enthusiastically into setting up the necessary contacts, getting all the work underway, and clearing the legal hurdles. Hammerschmidt-Hummel was especially grateful to University of Mainz librarian Heike Geisel, who had worked for nearly five years to carry out the large-scale digitalization of a total of 8,800 items. Frau Geisel was also extremely resourceful in devising ways of making the collection yield even more, e.g. by classifying and cross-linking the data, assembling clusters of individual topics that lend themselves to research, and (in collaboration with the art historian Dr Klaus Weber) making the archive's index of artists compatible with the data-bank of artists held by the University of Mainz Institute of Art History. In addition, she compiled an extremely helpful 'users' guide' to the new digital collection. Frau Geisel had enjoyed invaluable support from Dr Annette Holzapfel-Pschorn, the leading academic in the Central IT Department at the University, who set up an intelligent, most impressive Web interface using the latest application technologies. Frau Geisel and Dr Holzapfel-Pschorn were highly praised for their convincing demonstration, using illustrations to Hamlet, of how to access this well-devised and exceptionally user-friendly Web version. For legal reasons, Prof. Hammerschmidt-Hummel pointed out, the collection could not be released for open access on the internet. The media - as Dr Anderhub stressed in his foreword - had shown great interest in the new digital collection of thousands of Shakespearean illustrations (cf. Benjamin Cor's TV feature in "Tagesthemen", 17 November 2008, presented by Tom Buhrow). The ‘Oppel-Hammerschmidt Shakespeare Illustration Archive’ should also meet with particular interest not only among academic specialists, but also among the performers of the arts and persons active in the cultural realm in general, as well as theatre and film directors, literary managers, teachers, and countless Shakespeare enthusiasts.

Filologia Classica: dal segno, al suono, al significato

Il lavoro presenta le ricerche svolte ed i risultati ottenuti per consentire alle persone non vedenti lo studio quanto più autonomo del greco antico tramite sintesi vocale. Una introduzione storica ripercorre la prima vicenda professionale dell'esercizio della professione docente delle lettere classiche da parte di un soggetto privo di vista, mentre il riferimento alla legislazione contemporanea tenta di disegnare una cornice capace dei più moderni approdi supportati dalle tecnologie informatiche. La Tesi illustra infine il funzionamento dei vari dispositivi prodotti, mentre una importante appendice ripercorre le pubblicazioni via via curate dal Gruppo di Studio, accogliendo infine le trascrizioni dei codici di programmazione delle sintesi vocali realizzate. Essa affida così all'Università la prosecuzione delle ricerche delineando ulteriori ipotesi di sviluppo.

Willem Marinus Dudok. Progetti urbani per la citta' di Hilversum

Il tema principale affrontato dalla presente ricerca è quello dell’architettura della città; attraverso lo studio dei progetti urbani redatti dall’architetto Willem Marinus Dudok per la città di Hilversum, la tesi vuole confermare l’ipotesi che la costruzione dei “luoghi urbani” collettivi è il fulcro dell’idea di architettura che porta alla costruzione della città. La ricerca si propone di studiare il contributo dato da Dudok al progetto dello sviluppo urbano della città olandese, considerando un arco temporale che va dal 1915, anno in cui l’architetto viene designato a ricoprire la carica di direttore del locale ufficio Lavori Pubblici, al 1954, anno simbolico della sua nomina a cittadino onorario di Hilversum. Il lavoro di ricerca vuole individuare quelle caratteristiche formali e tipologiche, insite nei quartieri progettati dall’architetto olandese, in grado di definire una struttura urbana capace di sostenere un ragionamento architettonico indipendente dal luogo e dal tempo, un ragionamento impostato sulla definizione della forma urbis. Non desidera certo delineare un modello, vista la consapevolezza che ogni progetto ha un proprio luogo e un proprio tempo, cerca di tratteggiare, piuttosto, uno scenario possibile per il progetto urbano, capace di assurgere ad exemplum per la costruzione della città. I progetti analizzati riguardano edifici residenziali e spazi urbani per la collettività; questi rappresentano veri e propri nuclei aggregativi per la costruzione dei complessi di alloggi popolari, dei quali definiscono la scena fissa delle vicende umane. Lo studio di questi quartieri rappresenta, pertanto, il tentativo di decodificare un “modo” di comporre la città dal quale sia possibile estrapolare temi validi e di carattere generale che permettano di formalizzare una serie di utili insegnamenti, tramite i quali poter pensare alla realizzazione della stessa, nella convinzione che “la qualità del progetto consiste nella qualità dei caratteri del tema e nel loro riconoscimento nelle forme dell’architettura”.

Cytarabine dose for acute myeloid leukemia

Cytarabine (ara-C) is an important drug in the treatment of acute myeloid leukemia (AML). High-dose cytarabine (2000 to 3000 mg per square meter of body-surface area) is toxic but results in higher rates of relapse-free survival than does the conventional dose of 100 to 400 mg per square meter. Intermediate dose levels have not been thoroughly evaluated.

[A million football fans in a city of 120,000 inhabitants--a nightmare for emergency medicine and disaster management? Euro 2008 and the "Orange wonder of Berne"]

The 2008 European Football Championship 2008 (Euro 08) is the largest sporting event ever organized in Switzerland. One million visitors came to the city of Berne during the event and the local airport in Bern/Belp registered 261 extra flights. For each football game there were 33,000 fans in the stadium and 100,000 fans in the public viewing zones.The ambulance corps and the Department of Emergency Medicine (ED) at Inselspital, University Hospital Berne, were responsible for basic medical care and emergency medical management. Injuries and illnesses were analyzed by a standardized score (NACA score). The preparation strategy as well as costs and patient numbers are presented in detail.A total of 30 additional ambulance vehicles were used, 4,723 additional working days (one-third medical professionals) were accumulated, 662 ambulance calls were registered and 240 persons needed medical care (62% Swiss, 28% Dutch and 10% other nationalities). Among those needing treatment 51 were treated in 1 of the 4 city hospitals. No injuries with NACA grades VI and VII occurred (NACA I: 4, NACA II: 17, NACA III: 16, NACA IV: 10 and NACA V: 4 patients). The city of Berne compensated the Inselspital Bern with a total of 112,603 Euros for extra medical care costs. The largest amount was spent on security measures (50,300 Euros) and medical staff (medical doctors 22,600 Euros, nurses 29,000 Euros). Because of the poor weather and the exemplary behavior of the fans, the course of events was rather peaceful.

Autologous peripheral blood stem cell transplantation for acute myeloid leukemia

We report the results of a prospective, randomized phase 3 trial evaluating autologous peripheral blood stem cell transplantation (ASCT) versus intensive consolidation chemotherapy in newly diagnosed AML patients in complete remission (CR1). Patients with AML (16-60 years) in CR1 after 2 cycles of intensive chemotherapy and not eligible for allogeneic SCT were randomized between intensive chemotherapy with etoposide and mitoxantrone or ASCT ater high-dose cyclophosphamide and busulfan. Of patients randomized (chemotherapy, n = 259; ASCT, n = 258), more than 90% received their assigned treatment. The 2 groups were comparable with regard to prognostic factors. The ASCT group showed a markedly reduced relapse rate (58% vs 70%, P = .02) and better relapse-free survival at 5 years (38% vs 29%, P = .065, hazard ratio = 0.82; 95% confidence interval, 0.66-1.1) with nonrelapse mortality of 4% versus 1% in the chemotherapy arm (P = .02). Overall survival was similar (44% vs 41% at 5 years, P = .86) because of more opportunities for salvage with second-line chemotherapy and stem cell transplantation in patients relapsing on the chemotherapy arm. This large study shows a relapse advantage for ASCT as postremission therapy but similar survival because more relapsing patients on the chemotherapy arm were salvaged with a late transplantation for relapse. This trial is registered at www.trialregister.nl as #NTR230 and #NTR291.