Spectroscopic signatures from first principles calculations: from surface adsorbates to liquids and polymers

In dieser Arbeit werden drei wasserstoffverbrückte Systeme in der kondensierten Phase mit Hilfe von first-principles-Elektronenstruktur-Rechnungen untersucht, die auf der Dichtefunktionaltheorie (DFT) unter periodischen Randbedingungen basieren. Ihre lokalen Konformationen und Wasserstoffbrückenbindungen werden mittels ab-initio Molekulardynamiksimulationen berechnet und weiterhin durch die Bestimmung ihrer spektroskopischen Parameter charakterisiert. Der Schwerpunkt liegt dabei auf lokalen Strukturen und auf schnellen Fluktuationen der Wasserstoffbrückenbindungen, welche von zentraler Bedeutung für die physikalischen und chemischen Eigenschaften der betrachteten Systeme sind. Die für die lokalen, instantanen Konformationen berechneten Spektren werden verwendet, um die physikalischen Prozesse, die hinter den untersuchten Phänomenen stehen, zu erklären: die Wasseradsorption auf metallischen Oberflächen, die Ionensolvatisierung in wässrigen Lösungen und der Protonentransport in protonleitenden Polymeren, welche Prototypen von Membranen für Brennstoffzellen sind. Die Möglichkeit der Vorhersage spektroskopischer Parameter eröffnet vielfältige Möglichkeiten des Dialogs zwischen Experimenten und numerischen Simulationen. Die in dieser Arbeit vorgestellten Ergebnisse zeigen, dass die Zuverlässigkeit dieser theoretischen Berechnungen inzwischen für viele experimentell relevante Systeme ein quantitatives Niveau erreicht hat.

Quantum effects and dynamics in hydrogen-bonded systems: a first-principles approach to spectroscopic experiments

Computer simulations have become an important tool in physics. Especially systems in the solid state have been investigated extensively with the help of modern computational methods. This thesis focuses on the simulation of hydrogen-bonded systems, using quantum chemical methods combined with molecular dynamics (MD) simulations. MD simulations are carried out for investigating the energetics and structure of a system under conditions that include physical parameters such as temperature and pressure. Ab initio quantum chemical methods have proven to be capable of predicting spectroscopic quantities. The combination of these two features still represents a methodological challenge. Furthermore, conventional MD simulations consider the nuclei as classical particles. Not only motional effects, but also the quantum nature of the nuclei are expected to influence the properties of a molecular system. This work aims at a more realistic description of properties that are accessible via NMR experiments. With the help of the path integral formalism the quantum nature of the nuclei has been incorporated and its influence on the NMR parameters explored. The effect on both the NMR chemical shift and the Nuclear Quadrupole Coupling Constants (NQCC) is presented for intra- and intermolecular hydrogen bonds. The second part of this thesis presents the computation of electric field gradients within the Gaussian and Augmented Plane Waves (GAPW) framework, that allows for all-electron calculations in periodic systems. This recent development improves the accuracy of many calculations compared to the pseudopotential approximation, which treats the core electrons as part of an effective potential. In combination with MD simulations of water, the NMR longitudinal relaxation times for 17O and 2H have been obtained. The results show a considerable agreement with the experiment. Finally, an implementation of the calculation of the stress tensor into the quantum chemical program suite CP2K is presented. This enables MD simulations under constant pressure conditions, which is demonstrated with a series of liquid water simulations, that sheds light on the influence of the exchange-correlation functional used on the density of the simulated liquid.

Contour integration and principles of perceptual grouping

Ziel der Arbeit ist die Analyse von Prinzipien der Konturintegration im menschlichen visuellen System. Die perzeptuelle Verbindung benachbarter Teile in einer visuellen Szene zu einem Ganzen wird durch zwei gestalttheoretisch begründete Propositionen gekennzeichnet, die komplementäre lokale Mechanismen der Konturintegration beschreiben. Das erste Prinzip der Konturintegration fordert, dass lokale Ähnlichkeit von Elementen in einem anderen Merkmal als Orientierung nicht hinreicht für die Entdeckung von Konturen, sondern ein zusätzlicher statistischer Merkmalsunterschied von Konturelementen und Umgebung vorliegen muss, um Konturentdeckung zu ermöglichen. Das zweite Prinzip der Konturintegration behauptet, dass eine kollineare Ausrichtung von Konturelementen für Konturintegration hinreicht, und es bei deren Vorliegen zu robuster Konturintegrationsleistung kommt, auch wenn die lokalen merkmalstragenden Elemente in anderen Merkmalen in hohem Maße zufällig variieren und damit keine nachbarschaftliche Ähnlichkeitsbeziehung entlang der Kontur aufweisen. Als empirische Grundlage für die beiden vorgeschlagenen Prinzipien der Konturintegration werden drei Experimente berichtet, die zunächst die untergeordnete Rolle globaler Konturmerkmale wie Geschlossenheit bei der Konturentdeckung aufweisen und daraufhin die Bedeutung lokaler Mechanismen für die Konturintegration anhand der Merkmale Kollinearität, Ortsfrequenz sowie der spezifischen Art der Interaktion zwischen beiden Merkmalen beleuchten. Im ersten Experiment wird das globale Merkmal der Geschlossenheit untersucht und gezeigt, dass geschlossene Konturen nicht effektiver entdeckt werden als offene Konturen. Das zweite Experiment zeigt die Robustheit von über Kollinearität definierten Konturen über die zufällige Variation im Merkmal Ortsfrequenz entlang der Kontur und im Hintergrund, sowie die Unmöglichkeit der Konturintegration bei nachbarschaftlicher Ähnlichkeit der Konturelemente, wenn Ähnlichkeit statt über kollineare Orientierung über gleiche Ortsfrequenzen realisiert ist. Im dritten Experiment wird gezeigt, dass eine redundante Kombination von kollinearer Orientierung mit einem statistischen Unterschied im Merkmal Ortsfrequenz zu erheblichen Sichtbarkeitsgewinnen bei der Konturentdeckung führt. Aufgrund der Stärke der Summationswirkung wird vorgeschlagen, dass durch die Kombination mehrerer Hinweisreize neue kortikale Mechanismen angesprochen werden, die die Konturentdeckung unterstützen. Die Resultate der drei Experimente werden in den Kontext aktueller Forschung zur Objektwahrnehmung gestellt und ihre Bedeutung für die postulierten allgemeinen Prinzipien visueller Gruppierung in der Konturintegration diskutiert. Anhand phänomenologischer Beispiele mit anderen Merkmalen als Orientierung und Ortsfrequenz wird gezeigt, dass die gefundenen Prinzipien Generalisierbarkeit für die Verarbeitung von Konturen im visuellen System beanspruchen können.

Riorganizzazione di un distribution center mediante le tecniche di lean production: il caso Gambro Dasco spa

La Lean Production è un tema di estrema attualità per tutte le aziende che abbiano compreso l’importanza di produrre di più, con le risorse che si hanno a disposizione, eliminando sistematicamente tutte le attività che non creano valore aggiunto. La Produzione Snella è diventato un metodo per incrementare la competitività, riducendo l’incertezza e aumentando il servizio fornito al cliente. Nella realtà attuale vi è ancora una scarsa diffusione dei concetti Lean. Le cause di questo problema sono imputabili soprattutto alla cultura del management aziendale, alla mancanza di efficaci strumenti tecnologici a supporto, e in alcuni casi, la scarsa disponibilità delle imprese ad abbracciare la filosofica “snella”. La presente tesi, dopo una panoramica introduttiva su l’origine e l’evoluzione del Pensiero Snello e l’analisi di tutti i tools disponibili per combattere lo spreco; si propone di analizzare l’applicazione degli stessi in Gambro Dasco, multinazionale biomedicale leader nella vendita delle sue apparecchiature per dialisi.

EPR spectroscopy as a tool for the elucidation of non-covalent structuring principles in complex soft matter

This thesis aims at connecting structural and functional changes of complex soft matter systems due to external stimuli with non-covalent molecular interaction profiles. It addresses the problem of elucidating non-covalent forces as structuring principle of mainly polymer-based systems in solution. The structuring principles of a wide variety of complex soft matter types are analyzed. In many cases this is done by exploring conformational changes upon the exertion of external stimuli. The central question throughout this thesis is how a certain non-covalent interaction profile leads to solution condition-dependent structuring of a polymeric system.rnTo answer this question, electron paramagnetic resonance (EPR) spectroscopy is chosen as the main experimental method for the investigation of the structure principles of polymers. With EPR one detects only the local surroundings or environments of molecules that carry an unpaired electron. Non-covalent forces are normally effective on length scales of a few nanometers and below. Thus, EPR is excellently suited for their investigations. It allows for detection of interactions on length scales ranging from approx. 0.1 nm up to 10 nm. However, restriction to only one experimental technique likely leads to only incomplete pictures of complex systems. Therefore, the presented studies are frequently augmented with further experimental and computational methods in order to yield more comprehensive descriptions of the systems chosen for investigation.rnElectrostatic correlation effects in non-covalent interaction profiles as structuring principles in colloid-like ionic clusters and DNA condensation are investigated first. Building on this it is shown how electrostatic structuring principles can be combined with hydrophobic ones, at the example of host-guest interactions in so-called dendronized polymers (denpols).rnSubsequently, the focus is shifted from electrostatics in dendronized polymers to thermoresponsive alkylene oxide-based materials, whose structuring principles are based on hydrogen bonds and counteracting hydrophobic interactions. The collapse mechanism in dependence of hydrophilic-hydrophobic balance and topology of these polymers is elucidated. Complementarily the temperature-dependent phase behavior of elastin-like polypeptides (ELPs) is investigated. ELPs are the first (and so far only) class of compounds that is shown to feature a first-order inverse phase transition on nanoscopic length scales.rnFinally, this thesis addresses complex biological systems, namely intrinsically disordered proteins (IDPs). It is shown that the conformational space of the IDPs Osteopontin (OPN), a cytokine involved in metastasis of several kinds of cancer, and BASP1 (brain acid soluble protein one), a protein associated with neurite outgrowth, is governed by a subtle interplay between electrostatic forces, hydrophobic interaction, system entropy and hydrogen bonds. Such, IDPs can even sample cooperatively folded structures, which have so far only been associated with globular proteins.

"Applicazioni della metodologia lean six sigma nel settore dei servizi: Il caso caricese"

In questo momento i servizi costituiscono il principale settore d’impiego e la maggior fonte di reddito per le economie sviluppate, rappresentando circa tre quarti del prodotto interno lordo sia negli Stati Uniti che nel Regno Unito. (Piercy e Rich, 2009) Nonostante però questa notevole importanza per l’economia, le organizzazioni di questo settore non riescono a fornire dei servizi di qualità tale da soddisfare le richieste dei clienti. (Piercy e Rich, 2009) Ancora più preoccupante è il risultato degli indicatori che forniscono un livello di qualità dei servizi in calo di anno in anno. (Dickson et al., 2005) Questo lavoro di tesi si occupa di analizzare il Lean Six Sigma come metodologia di cambiamento organizzativo e miglioramento dei processi aziendali, nel contesto dei servizi e in modo particolare in quelli finanziari. L’obiettivo di questo lavoro è quello di presentare il Lean Six Sigma applicato ai servizi analizzando i fattori critici di successo, i fattori ostativi, le barriere organizzative interne, le differenze tra il settore manifatturiero e quello dei servizi, gli strumenti, gli obiettivi e i benefici introdotti. Si vuole inoltre indagare l’applicazione di tale metodologia a un’azienda italiana di piccole e medie dimensioni esaminando le caratteristiche da tenere in considerazione durante la sua implementazione.

Analisi ed ottimizzazione del valore di performance dell'area assemblaggio in una multinazionale del settore metalmeccanico e definizione del ruolo di lean thinker

Ottimizzazione VARI dell'area assemblaggio in una multinazionale del settore metalmeccanico e definizione del ruolo del lean thinker per la gestione del sistema di lean production.

The Social Principles of Jesus: A Critical Re-examination of Walter Rauschenbusch’s Social Gospel

It has been nine decades since Walter Rauschenbusch (1861-1918) published a slim volume entitled The Social Principles of Jesus. Though today less well known than his other works Christianity and the Social Crisis (1907) and Theology for the Social Gospel (1917), it is Social Principles that most adeptly summarizes the theological ethics of Rauschenbusch’s “social gospel.” Taking the form of a pedagogical treatise, Social Principles reads as both a finely tuned analysis of the modern relevance of the teachings of Jesus, and an impassioned plea on the part of its author for an end to the folly of interpreting Christianity solely in “individualistic” terms. It is Rauschenbusch’s expressed aim to resurrect the core teachings of Jesus, which are social and ethical, and apply these to a renewed, socially conscious liberal democracy, establishing a grand harmony between religion, ethics, and social evolution. How far this vision was from the burgeoning “fundamentalism” of his day (and ours) is more than evidenced by the critical reaction of many of his more conservative peers, but also indicates the continuing relevance of his work for theologians and others looking for alternative paths. The following exposition is supplemented with appreciative and critical comments.