Morphology of extruded high-density polyethylene pipes studied by atomic force microscopy

Atomic force microscopy (AFM) was used to study the structure of extruded polyethylene (PE) pipe. During extrusion, the outer surface of the pipe was cooled with water. Two cross sections, parallel and transverse to the extrusion direction, were examined in order to spatially follow the structural development during extrusion. The morphology revealed was spherulitic, and the spherulites had a mostly banded appearance when viewed under the AFM. We were not able to distinguish an oriented skin layer at the surface of the pipe, either by AFM or polarizing microscopy. The changes in the pipe's structure resulting from the cooling conditions were found to be rather gradual, and no clearly defined zones were observed. A slight orientation towards the extrusion direction was detected only in the area of the pipe crystallized under the lowest degree of undercooling. Measured spherulitic size, band period, and lamellae thickness showed a gradual increase in their values from the cooled to the noncooled surface of the pipe. Transmission electron microscopy (TEM) was used to verify the band period and lamellae thickness measurements done by AFM

Regard littéraire sur la programmation comprise comme une écriture

International audienc

Over het belang van het hoger technisch onderwijs in België en Vlaanderen voor de democratisering en de expansie van het hoger onderwijs (1962-1999). Een literatuurstudie

The main thesis of the research is that the outcome of the democratization of the tertiary education in the second half of the twentieth century only exactly can be described and correctly evaluated if we also take into account the fast quantitative growth and the qualitative improvement of the not university tertiary education, – a research domain that remains almost an unexplored area. The tertiary technical education has underwent, in the second half of the twentieth century, a genuine metamorphose. From an isolated and a stand-alone education system – the consequence of the traditional non-intervention principle – this segment of tertiary education has grown out to an extremely important part of tertiary education. The number of students in tertiary technical education has shown a continuous increase. As a consequence there was a sufficient critical mass which permitted to evolve into a full-fledged form of tertiary education. This evolution was the consequence of the considerable post-war mutations in the demographic, economic, geopolitical and technological sectors of Belgian society which resulted seamlessly in the Golden Sixties. In addition the School Pact induced, from 1958, a counterbalance for the philosophical contrasts in turning the conflict- and confrontation model into a consultation model. The qualitative improvement was based on three elements. First of all, there was the principle of proximity in legal, financial, physical, geographic and social respect. Then there was the practice of an appropriate, at that time a somewhat peculiar pedagogical concept: integrated education. Herein, the general education and the technical training were processed to a synthesis, often combined with a curriculum inversion. Finally there was the relatively short study duration, mostly two or three years. In the end the result was a limitation of the (direct) study costs and a reduction of the psycho-social obstacles to continue studying, because the friction (the status incongruity) remained manageable between the social assigned origin status (ascription) and the acquired professional status (achievement). The legal and decretal framework reflected this metamorphose: the royal decision of 14 November 1962 classified the tertiary technical education into three hierarchical degrees, the law of 7 July 1970 worked out a general structure of the tertiary education and the decrees of 1991 and 1994 did the same for the not university tertiary education. After the implementation of the Bologna Declaration (1999), this set of regulations will be integrated into the Codex Tertiary Education (2013). In the analysis of the government’s promotion of the democratization of the participation in tertiary education, there can be seen a pattern of finding new insights in exogenous and endogenous inhibiting factors. Originally, democratization was considered as a financial problem. From the sixties the focus shifted first to an improvement (the so-called omnivalence law of 1964) and subsequently to a replacement of the vertical/categorically by a horizontal/ comprehensive education structure (the renewed secondary education law of 1971 and the unit type decree of 1989). In the eighties the main topic was the gender problems and in the nineties the ethnicity problems. Currently, the participation in education is rather considered as a multidimensional problem of autochthonous and immigrant underprivileged/disadvantaged groups, a problem that requires an integrated approach. On the basis of Kyvik’s analysis of The Dynamics of Change in Higher Education. Expansion and Contraction in an organizational Field (2009), attention is given to the structural change in the Belgian/Flemish tertiary education from a binary system to a unified system, embedded in a secular trend (1830-1999).status: publishe

Programmation de jeux vidéo en C# sous Unity3D, présentation d'un projet de jeu sérieux (descriptif d’atelier)

International audienc

Module Development - Get the Drupal started

Deze sessie wil beginnende drupal developers op weg helpen op basis van eigen ervaringen en eenvoudige, werkende voorbeelden. Tijdens het voorbije jaar ging veel tijd verloren om iets werkend te krijgen. De stijle leercurve, nieuwe concepten en massa's documentatie maken het knap lastig om je weg te vinden bij het ontwikkelen van modules. Inhoud Na een inleiding van concepten - arrays, hooks, ... - worden met demo's de tools en de verschillende aspecten van module development belicht: •devel module; •eenvoudig theming voorbeeld (hoe voeg je custom theming toe en hoe kan je die dan gebruiken); •een elementair form voorbeeld (illustratie van form API, validation en form submission); •een block voorbeeld met permissions; •een preprocess voorbeeld (hoe de 'read more' link aanpassen) •een form_alter voorbeeldstatus: publishe

Diagnostic rapide de la tuberculose pulmonaire par extraction automatisée d'ADN suivie de PCR en temps réel à partir d'échantillons respiratoires décontaminés et non décontaminés

PARIS-BIUP (751062107) / SudocSudocFranceF