CONALI ontology. A framework for design and evaluation of constructively aligned courses in higher education: putting in focus the educational goal verbs

An increasing number of Higher Education professionals have embraced the Constructivism theory in contrast with the traditional transmissive pedagogy approach where the focal figure is the teacher. Constructivists emphasizes that the learners acquire, or construct, knowledge through their own activities and previous knowledge. Teacher role is to set up an environment that can provide a good learning experience for the students. In view of this the alignment of the intended learning outcome (ILO) with the teaching and learning activity (TLA) and the assessment task (AT) of the course becomes an important requirement for good learning. The driver of the alignment is the educational goal verb (EGV) that represents the educational goal underling a specific intended learning outcome (ILO). This verb should be elicited by the course’s TLA and be the base for the consequent AT. The convergence of constructivism with this concept generates the constructive alignment pedagogical paradigm. The CONALI ontology answers the requirement for a structured framework to describe the vast body of knowledge developed in such a field. The salient aspects of constructive alignment have been extracted and classified in a comprehensive taxonomy. The following description of the semantic relationships among the different classes resulted in the CONALI ontology. The chosen modelling language is OWL: this provides the possibility to describe in a computer understandable way a higher education courses to an unprecedented level of detail. OWL enables also the creation of a specific knowledge base by populating the model. The knowledge base can then be analysed and interrogated on many important issues concerning the alignment of the instantiated course. The CONALI ontology becomes an important tool to design and synthesize the related domain knowledge. This paper proves the usability of CONALI ontology as tool to represent the courses in an engineering program and evaluate the alignment of their activities. The specific instantiation is based on the Industrial Engineering program at KTH Royal Institute of Technology in Stockholm, Sweden

Non-destructive detection of machining-induced white layers through grain size and crystallographic texture-sensitive methods

Detection of machining-induced white layers is currently a destructive inspection process with a form of cross-sectional microscopy required. This paper, therefore, reports on the development of a novel non-destructive inspection method for detecting white layers using grain size-sensitive and crystallographic texture-sensitive techniques. It is shown that x-ray diffraction can be used to detect white layers as thin as 5 μm in Ti-6Al-4 V through measurement of diffraction peak breadths and diffraction peak intensities, due to the influence of the sub 100 nm grain size and high lattice strain in the white layer, as well as the strong crystallographic texture in this titanium alloy. Compared to the existing optical microscopy inspection method, which can take days due to the number of steps involved, the x-ray diffraction peak breadth method offers non-destructive white layer detection in a matter of minutes at a resolution of 5 μm or less that competes directly with the optical method. Spatially resolved acoustic spectroscopy, a laser-generated ultrasonic surface acoustic wave detection method, can also be used to identify anomalous surfaces, containing a white layer or swept grain material, due to its sensitivity to the crystallographic texture changes that arise in severely plastically deformed Ti-6Al-4V as in Titanium with 6 % Aluminium and 4% Vanadium

Oxidative stress in the developing brain: effects of postnatal glucocorticoid therapy and antioxidants in the rat.

In premature infants, glucocorticoids ameliorate chronic lung disease, but have adverse effects on long-term neurological function. Glucocorticoid excess promotes free radical overproduction. We hypothesised that the adverse effects of postnatal glucocorticoid therapy on the developing brain are secondary to oxidative stress and that antioxidant treatment would diminish unwanted effects. Male rat pups received a clinically-relevant tapering course of dexamethasone (DEX; 0.5, 0.3, and 0.1 mg x kg(-1) x day(-1)), with or without antioxidant vitamins C and E (DEXCE; 200 mg x kg(-1) x day(-1) and 100 mg x kg(-1) x day(-1), respectively), on postnatal days 1-6 (P1-6). Controls received saline or saline with vitamins. At weaning, relative to controls, DEX decreased total brain volume (704.4±34.7 mm(3) vs. 564.0±20.0 mm(3)), the soma volume of neurons in the CA1 (1172.6±30.4 µm(3) vs. 1002.4±11.8 µm(3)) and in the dentate gyrus (525.9±27.2 µm(3) vs. 421.5±24.6 µm(3)) of the hippocampus, and induced oxidative stress in the cortex (protein expression: heat shock protein 70 [Hsp70]: +68%; 4-hydroxynonenal [4-HNE]: +118% and nitrotyrosine [NT]: +20%). Dexamethasone in combination with vitamins resulted in improvements in total brain volume (637.5±43.1 mm(3)), and soma volume of neurons in the CA1 (1157.5±42.4 µm(3)) and the dentate gyrus (536.1±27.2 µm(3)). Hsp70 protein expression was unaltered in the cortex (+9%), however, 4-HNE (+95%) and NT (+24%) protein expression remained upregulated. Treatment of neonates with vitamins alone induced oxidative stress in the cortex (Hsp70: +67%; 4-HNE: +73%; NT: +22%) and in the hippocampus (NT: +35%). Combined glucocorticoid and antioxidant therapy in premature infants may be safer for the developing brain than glucocorticoids alone in the treatment of chronic lung disease. However, antioxidant therapy in healthy offspring is not recommended

MRI and CT in the diagnosis of coronary artery disease: indications and applications

In recent years, technical advances and improvements in cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI) have provoked increasing interest in the potential clinical role of these techniques in the non-invasive work-up of patients with suspected coronary artery disease (CAD) and correct patient selection for these emerging imaging techniques. In the primary detection or exclusion of significant CAD, e.g. in the patient with unspecific thoracic complaints, and also in patients with known CAD or advanced stages of CAD, both CT and MRI yield specific advantages. In this review, the major aspects of non-invasive MR and CT imaging in the diagnosis of CAD will be discussed. The first part describes the clinical value of contrast-enhanced non-invasive CT coronary angiography (CTCA), including the diagnostic accuracy of CTCA for the exclusion or detection of significant CAD with coronary artery stenoses that may require angioplastic intervention, as well as potentially valuable information on the coronary artery vessel wall. In the second section, the potential of CT for the imaging of myocardial viability and perfusion will be highlighted. In the third and final part, the range of applications of cardiac MRI in CAD patients will be outlined

Theoretical and experimental study of tooling systems : passive control of machining vibration

Vibration control has been and still remains a subject of primary importance in modern manufacturing industry. To be able to remove high volumes of material in shorter time as well as to be able to get the right quality of the parts at the first time are goals that many shops would like to achieve. Tooling systems, and especially cantilever tools, and cantilever structural units of machine tools are the least rigid components of machining systems and therefore the most prone to vibration. Boring tools are often encountered as rotating tools in machining centres or as stationary tools in internal turning. In this thesis the focus is on internal turning. Internal turning is widely known as a very delicate operation and it is often carried out with cutting parameters far from optimal, from a productivity point of view, due to limitations imposed by vibration. Another type of tooling system whose functionality is impaired by vibration is the parting-off tool. The design of damped parting-off tool is one of the focus of this thesis as well. Vibration control has the purpose to achieve an efficient energy dissipation of a vibrational system. Basically this is achieved by controlling the damping of the system. Since damping involves the conversion of energy associated with a vibration to other forms, there are several mechanisms to remove energy from a vibrating system. Typically these mechanisms are divided in two classes: 1. Mechanisms that convert mechanical energy to heat, i.e. passive damping. 2. Mechanisms that transport energy away from vibrating systems, i.e. active damping. Both these techniques have been used during the years and both have been giving excellent results. The active vibration control mechanisms are more expensive and not suitable for machining due to the cables they necessitate that could interfere with the machining operation. This work proposes an original approach to vibration damping in machining systems, the objects of vibration dissipation being the structural components on the link between turret and cutting insert. The idea is to use composite materials to create damping interfaces between and within the different structural components. Different clamping system designs are being compared in order to see how these influence the performance of the machining system and different cutting inserts have been compared for machining hardened steel. The newly designed components have been going through both extensive off-line (modal analysis) and on-line dynamic testing (machining test) and the results show that the new tool holders used in combination with hydrostatic clamping system are the most optimal solution among the tested ones. The new design for the turret has been giving promising results and more can be achieved by bringing minor changes to it, these changes are being implemented at the time of writing this thesis.QC 2010110

Theoretical and experimental study of tooling systems : passive control of machining vibration

Vibration control has been and still remains a subject of primary importance in modern manufacturing industry. To be able to remove high volumes of material in shorter time as well as to be able to get the right quality of the parts at the first time are goals that many shops would like to achieve. Tooling systems, and especially cantilever tools, and cantilever structural units of machine tools are the least rigid components of machining systems and therefore the most prone to vibration. Boring tools are often encountered as rotating tools in machining centres or as stationary tools in internal turning. In this thesis the focus is on internal turning. Internal turning is widely known as a very delicate operation and it is often carried out with cutting parameters far from optimal, from a productivity point of view, due to limitations imposed by vibration. Another type of tooling system whose functionality is impaired by vibration is the parting-off tool. The design of damped parting-off tool is one of the focus of this thesis as well. Vibration control has the purpose to achieve an efficient energy dissipation of a vibrational system. Basically this is achieved by controlling the damping of the system. Since damping involves the conversion of energy associated with a vibration to other forms, there are several mechanisms to remove energy from a vibrating system. Typically these mechanisms are divided in two classes: 1. Mechanisms that convert mechanical energy to heat, i.e. passive damping. 2. Mechanisms that transport energy away from vibrating systems, i.e. active damping. Both these techniques have been used during the years and both have been giving excellent results. The active vibration control mechanisms are more expensive and not suitable for machining due to the cables they necessitate that could interfere with the machining operation. This work proposes an original approach to vibration damping in machining systems, the objects of vibration dissipation being the structural components on the link between turret and cutting insert. The idea is to use composite materials to create damping interfaces between and within the different structural components. Different clamping system designs are being compared in order to see how these influence the performance of the machining system and different cutting inserts have been compared for machining hardened steel. The newly designed components have been going through both extensive off-line (modal analysis) and on-line dynamic testing (machining test) and the results show that the new tool holders used in combination with hydrostatic clamping system are the most optimal solution among the tested ones. The new design for the turret has been giving promising results and more can be achieved by bringing minor changes to it, these changes are being implemented at the time of writing this thesis.QC 2010110

Improving Machining System Performance through designed-in Damping : Modelling, Analysis and Design Solutions

With advances in material technology, allowing, for instance, engines to withstand higher combustion pressure and consequently improving performance, comes challenges to productivity. These materials are, in fact, more difficult to machine with regards to tool wear and especially machine tool stability. Machining vibrations have historically been one of the major limitations to productivity and product quality and the cost of machining vibration for cylinder head manufacturing has been estimated at 0.35 euro per part. The literature review shows that most of the research on cutting stability has been concentrating on the use of the stability limits diagram (SLD), addressing the limitations of this approach. On the other hand, research dedicated to development of machine tool components designed for chatter avoidance has been concentrating solely on one component at the time. This thesis proposes therefore to extend the stability limits of the machining system by enhancing the structure’s damping capability via a unified concept based on the distribution of damping within the machining system exploiting the joints composing the machine tool structure. The design solution proposed is based on the enhancement of damping of joint through the exploitation of viscoelastic polymers’ damping properties consciously designed as High Damping Interfaces (HDI). The tool-turret joint and the turret-lathe joint have been analysed. The computational models for dimensioning the HDI’s within these joints are presented in the thesis and validated by the experiments. The models offer the possibility of consciously design damping in the machining system structure and balance it with regards to the needed stiffness. These models and the experimental results demonstrate that the approach of enhancing joint damping is viable and effective. The unified concept of the full chain of redesigned components enables the generation of the lowest surface roughness over the whole range of tested cutting parameters. The improved machining system is not affected by instability at any of the tested cutting parameters and offers an outstanding surface quality. The major scientific contribution of this thesis is therefore represented by the proposed unified concept for designing damping in a machining system alongside the models for computation and optimisation of the HDIs. From the industrial application point of view, the presented approach allows the end user to select the most suitable parameters in terms of productivity as the enhanced machine tool system becomes less sensitive to stability issues provoked by difficult-to-machine materials or fluctuations of the work material properties that may occur in ordinary production processes.QC 20120413DampComatProduction 4 microFFI Robust Machinin

Valutazione della degenerazione delle cellule ganglionari retiniche in due modelli murini di neurodegenerazione

La malattia di Alzheimer (AD) e la sclerosi laterale amiotrofica (ALS) rappresentano due patologie neurodegenerative che sono, ad oggi, tra le maggiori cause di morbilità e di disabilità. In particolare, l’AD è il tipo più diffuso di demenza ed è caratterizzata sia da forme sporadiche che familiari ad insorgenza precoce. La maggior parte dei casi di malattia familiare di Alzheimer (FAD) sono associati a mutazioni autosomiche dominanti nei geni che codificano per la proteina precursore dell'amiloide (APP), per la presenilina 1 (PSEN1) e per la presenilina 2, implicati nel fisiologico processo di sintesi e proteolisi delle β-amiloidi (Aβ). Queste mutazioni comportano un’aumentata processazione dell’APP, con conseguente deposizione e aggregazione extracellulare di Aβ, le principali costituenti delle cosiddette placche amiloidi. Un altro elemento patogenetico è rappresentato dai grovigli neurofibrillari intraneuronali, che si vengono a formare in seguito a meccanismi di iperfosforilazione della proteina associata ai microtubuli tau. Tutti questi elementi, nell'insieme, contribuiscono in modo significativo all’alterazione del metabolismo cellulare a livello neuronale, provocando infiammazione, stress ossidativo, citotossicità, morte neuronale e declino cognitivo associato. Questa condizione viene riprodotta nel modello murino transgenico 5xFAD che presenta cinque mutazioni specifiche, di cui tre nel gene umano dell’APP e due nel gene umano della PSEN1, che comportano un’insorgenza più rapida della malattia. La ALS, invece, rappresenta una malattia neurodegenerativa progressiva e potenzialmente fatale, caratterizzata da atrofia muscolare neurogena e paralisi dovute alla perdita dei motoneuroni corticali e spinali. Una delle cause alla base della sua patogenesi è rappresentata da mutazioni autosomiche dominanti nel gene della superossido dismutasi 1 (SOD1), che codifica per un importante enzima antiossidante cellulare. Per studiare le caratteristiche di questa patologia è stato selezionato il modello murino transgenico SOD1G93A che esprime una forma mutante del gene umano. Questa condizione comporta un fenotipo simile a quello dell’uomo con degenerazione progressiva dei motoneuroni associata a morte neuronale, gliosi e accumulo di proteine mal ripiegate e ubiquitinate. Quest'ultimo processo, in particolare, sembrerebbe essere legato alla presenza di prodotti proteici SOD1 anomali, caratterizzati da una struttura instabile, perdita della funzione enzimatica e proni alla formazione di aggregati insolubili che risultano in condizioni di stress ossidativo e neurotossicità a livello di motoneuroni e cellule gliali. Lo scopo di questa tesi è quello di caratterizzare le principali alterazioni strutturali, funzionali e molecolari a livello retinico in questi modelli murini, in linea con l’obiettivo finale di elaborare una terapia genica a RNA, che possa permettere di intervenire contro la neurodegenerazione in modelli animali di note patologie. In questo contesto, la retina viene utilizzata come modello di sistema nervoso centrale trattandosi, a tutti gli effetti, di una porzione integrale ma dislocata, e perciò di più facile accesso. Gli animali sono stati valutati periodicamente tramite elettroretinogramma e tomografia a coerenza ottica, al fine di evidenziare alterazioni funzionali e strutturali retiniche e poter così seguire il declino nel tempo. Allo stesso modo, sono state condotte analisi molecolari tramite Western Blot al fine di valutare l’espressione proteica dei principali marker associati a stress ossidativo, quali il fattore di trascrizione nucleare eritroide-2 (Nrf-2), la eme-ossigenasi 1 (HO-1), la NADPH chinone ossidoreduttasi, e del marker di disfunzione mitocondriale citocromo c (Cyt-c). Infine, sono stati analizzati anche i livelli di alcune proteine che risultano maggiormente espresse in condizioni di neuroinfiammazione come la proteina fibrillare acida della glia (GFAP), la molecola 1 dell'adattatore legante il calcio ionizzato (IBA-1), il fattore nucleare κB (NF-κB) e la sua forma fosforilata (pNF-κB). A conclusione di questo elaborato di tesi, si riscontra la presenza di alterazioni funzionali, strutturali e molecolari nel modello 5xFAD già a partire dai 6 mesi e alterazioni funzionali e molecolari nel modello SOD1 a 90 giorni di età. Nel complesso, questi risultati sottolineano come l’indagine retinica rappresenti un approccio valido per la valutazione di processi patologici e alterazioni associati a malattie neurodegenerative, anche a tempi precoci. Questo elemento si rivela essenziale per la successiva applicazione nell’ambito della sperimentazione di nuove terapie

Influence of inserts coating and substrate on TooloxR44 machining

The objective of the research presented in this paper is to characterize the machinability of TOOLOX 44 during cutting with PALBIT inserts with focus on how different combinations of coatings and substrates influence the machining process in aspects such as tool life, cutting forces, temperature and chip forming process. The foremost result is that TOOLOX is machinable and when the right tool is chosen high productivity can be achieved. Using the right insert, equipped with chipbreaker, should allow to machine this hardened steel even at higher cutting speeds than the ones used in this investigation.QC 20101109</p