Studio preliminare riguardante un sistema di controllo dello stato dell’utensile e della qualità della lavorazione nella foratura di materiali compositi a matrice plastica.

Obiettivo di questa tesi è stato l’allestimento un laboratorio multisensoriale per l’applicazione della tecnica TCM (Tool Condition Monitoring) alla foratura di materiali compositi a matrice plastica rinforzati con fibra di carbonio, che permetta di quantificare l’usura dell’utensile con il progredire della lavorazione, sia direttamente tramite misure ottiche, sia indirettamente misurando l’andamento delle forze coinvolte nella processo e controllando al contempo la qualità del foro realizzato. La prima fase dell’allestimento del laboratorio è consistita nel collegamento e calibrazione dei vari sensori per la misurazione della forza di avanzamento, della coppia applicata all’utensile, della potenza assorbita e delle vibrazioni originate dal contatto punta-pezzo. Per poter gestire questi sensori è stato sviluppato un programma in ambiente LabView. E’ stata inoltre progettata e realizzata un’attrezzatura solidale alla macchina utensile che aspira i residui della lavorazione. La seconda fase è consistita invece nello sviluppo di un sistema ottico di misurazione dell’usura dell’utensile e del danneggiamento, sotto forma di delaminazione, del materiale attorno al foro. A tale scopo è stata realizzata un’attrezzatura flessibile che consente di acquisire in modo rapido e in condizioni ripetibili immagini a forte ingrandimento della punta e della zona attorno al foro. Sono stati elaborati dei programmi in ambiente Matlab per l’analisi di tali immagini e l’estrazione di parametri che quantificano l’usura dell’utensile e il danneggiamento del composito. Nell’ultima fase sono state condotte prove di foratura su vari materiali per validare il sistema di sensori e di acquisizione immagini. I risultati ottenuti, oltre che confermare il buon funzionamento del laboratorio e la sua utilità in questo genere di prove, hanno anche fornito interessanti indicazioni sui processi di foratura dei materiali compositi

Adiabatic-passage cross polarization in N-15 NMR spectroscopy of peptides weakly associated to phospholipids: Determination of large RDC

Structural information can be extracted from one-bond residual dipolar couplings (RDC) measured in NMR spectra of systems in field-ordered media. RDC can be on the order of J-couplings if the anisotropy of alignment is ~ 10−2, 10-fold stronger than that typically used for structural studies of water-soluble proteins. In such systems the performance of 1H→ 15N polarization transfer methods of the INEPT type is not satisfactory. In this study we show the effectiveness of adiabatic-passage cross-polarization (APCP) in transferring the 1H→ 15N polarization in the bicelle-associated peptide Leucine Enkephalin (Lenk). APCP is efficient both in static samples and in samples spun at the magic angle (MAS) or any other angle of the spinning axis to the magnetic field (variable-angle spinning, VAS). The anisotropic spectrum of an aligned static sample and the isotropic spectrum of the sample under MAS provide a set of possible values for the 1H-15N RDC of phospholipid-associated Lenk. The unambiguous determination of the 1H-15N RDC was accomplished by means of VAS experiment

CARTOGRAPHY FOR THE DIDACTICS AND DIDACTICS FOR THE CARTOGRAPHY

Ciò che emerge dall’analisi svolta sulle Università italiane è che, nonostante l’alto valore formativo, la cartografia, nelle Facoltà umanistiche, sembra aver perso il rilievo di un tempo. La riforma universitaria ha imposto che venisse operata una scelta: cartografia o geografia. Tale scelta è andata a scapito della cartografia, ma è evidente la consapevolezza che il linguaggio della geografia rimane basilare per coloro che devono insegnare e tramandare competenze per formare non solo geografi ma persone capaci di collocarsi nel mondo.The analysis carried out from the Italian University shows that, in spite of the high formative value, the cartography in the humanistic Faculties seems to have lost the importance/emphasis it had in the past. The university reform forced to choose between two subjects: cartography or geography. This choice has penalized cartography, but it stands to reason that the language of geography is fundamental for all those who have to learn and hand on competencies not only to geographers but also to people that will be part of the word

Chiroptical Properties and Absolute Configuration of Chiral, Open Chain Di- and Tri-substituted Allenes: a Polarizability Approach

A second order treatment of the optical activity of chiral diand tri-substituted open chain allenes, by means of the polarizability model of DeVoe, makes it possible to establish a simple relationship between optical rotatory power and absolute configuration of these compounds

Biological Solid-state NMR at ETH Zurich

Solid-state Magnetic Resonance has been greatly developed over the past decade. Higher field spectrometers and other technical developments are expected to lead to further significant improvements

NMR of bicelles: orientation and mosaic spread of the liquid-crystal director under sample rotation

Model-membrane systems composed of liquid-crystalline bicellar phases can be uniaxially oriented with respect to a magnetic field, thereby facilitating structural and dynamics studies of membrane-associated proteins. Here we quantitatively characterize a method that allows the manipulation of the direction of this uniaxial orientation. Bicelles formed from DMPC/DHPC are examined by 31P NMR under variable-angle sample-spinning (VAS) conditions, confirming that the orientation of the liquid-crystalline director can be influenced by sample spinning. The director is perpendicular to the rotation axis when Θ (the angle between the sample-spinning axis and the magnetic field direction) is smaller than the magic angle, and is parallel to the rotation axis when Θ is larger than the magic angle. The new 31P NMR VAS data presented are considerably more sensitive to the orientation of the bicelle than earlier 2H studies and the analysis of the sideband pattern allows the determination of the orientation of the liquid-crystal director and its variation over the sample, i.e., the mosaic spread. Under VAS, the mosaic spread is small if Θ deviates significantly from the magic angle but becomes very large at the magic angl

Switched-angle spinning applied to bicelles containing phospholipid-associated peptides

In a model study, the proton NMR spectrum of the opioid pentapeptide leucine-enkephalin associated with bicelles is investigated. The spectral resolution for a static sample is limited due to the large number of anisotropic interactions, in particular strong proton-proton couplings, but resolution is greatly improved by magic-angle sample spinning. Here we present two-dimensional switched-angle spinning NMR experiments, which correlate the high-resolution spectrum of the membrane-bound peptide under magic-angle spinning with its anisotropic spectrum, leading to well-resolved spectra. The two-dimensional spectrum allows the exploitation of the high resolution of the isotropic spectrum, while retaining the structural information imparted by the anisotropic interactions in the static spectrum. Furthermore, switched-angle spinning techniques are demonstrated that allow one to record the proton spectrum of ordered bicellar phases as a function of the angle between the rotor axis and the magnetic field direction, thereby scaling the dipolar interactions by a predefined facto

On the Chiroptical Behavior of Conjugated Multichromophoric Compounds of a New Pseudoaromatic Class: Bicolchicides and Biisocolchicides

It is well known that, stemming from the mutual interplay between chromophores, circular dichroism (CD) is a powerful technique to deal with structural problems for both the small organic molecule and the biopolymer. However, quantitative interpretations of the spectroscopic and structural terms that give rise to the exciton couplet are usually presented for ideal cases, or a few CD bands only are taken into account, overlooking the role of the solvent medium. Circular dichroism and UV absorption spectra were carried out for colchicide (3) and isocolchicide (6), as well as their coupling products, 10,10'-bicolchicide (2) and 9,9'-biisocolchicide (5), in both hydrogen bonding and non hydrogen bonding solvents, as well as MeCN/H(2)O mixtures. A dramatic control by the solvent emerged, as even tiny changes in the composition of solvent mixtures, at ca 1 water molar fraction, induced a dramatic modification of their CD bands. A mutarotation phenomenon--long known for isocolchicine (8)--was also observed for 5, and can be attributed to the interconversion between atropisomers (R(a),7S),(R(a),7'S)-5a and (R(a),7S),(S(a),7'S)-5b. Our data show that with molecules built on two structurally identical moieties which embody both hydrophilic and hydrophobic groups, even tiny changes in the composition of solvent mixtures cause a dramatic modification of the CD bands. Their analysis arrives at a qualitative rationalization of the observed CD couplets from the coupling of high energy transitions, while attempts at a quantitative interpretation of these phenomena through time-dependent density functional theory allowed to reproduce satisfactorily the CD spectrum in the 300-450 nm region only. Failure with higher energies probably reflects currently inadequate specific theoretical treatments of the solvent medium

INFLUÊNCIA DA ESTÉTICA VISUAL NA USABILIDADE E EXPERIÊNCIA DO USUÁRIO EM INTERFACES HUMANO-COMPUTADOR

This study aims to identify assessment tools that relate visual aesthetics, usability and user experience in HCI. For this, a systematic review was conducted on the basis Science Direct and Scopus. The results of the survey conducted bring the evaluation and synthesis of eight instruments found directly related to the subject.Este trabalho identifica instrumentos de avaliação que relacionam estética visual, usabilidade e experiência do usuário em HCI. Para tal, foi realizada uma revisão sistemática nas bases Science Direct e Scopus. Os resultados do levantamento realizado trazem a avaliação e síntese de oito instrumentos encontrados relacionados diretamente ao tema

Collaborative design methodologies for clothing flat modeling

This article reflects on the importance of collaborative design methodologies in the construction of new configurations for teaching flat clothing modeling. Within the field of teaching fashion and clothing, but specifically in the disciplines of flat modeling, several problems can be identified regarding teaching-learning. Silva and França (2018) state that there is little perceived ability to understand the execution of the molds on the part of the students, which cause the discipline to be seen with a high degree of complexity, causing dissatisfaction, both on the part of the students and by part of the teachers who teach it. This article is based on data, four surveys carried out in fashion and clothing courses in Brazil regarding teaching-learning of the flat modeling technique and from the gaps identified in its results, we will substantiate the paths taken by this research.Based on the assumption that the understanding of the reasons and the difficulties present in the contexts of the researches carried out on teaching and learning of flat modeling in recent years, are not due to individual and solitary actions, but to collective constructions of all the authors involved. In this work, concepts of collaborative design methodologies are explored, as innovative and effective methods of this construction. Understanding that, through collaborative means, it is possible to contribute with activities and solutions from different fields, starting from a new perspective when conceiving formal concepts and solutions.Thus, the question that guides this study and which will be answered is: how can collaborative design methodologies contribute to the flat modeling of clothing? The article is structured in four topics, which aims to clarify points and difficulties raised in research that were carried out in recent years on teaching and learning of flat modeling through a systematic literature review that points out data on the state of the art of flat modeling and its relationship with collaborative methodologies