Role of hydrostatic paradoxes towards the formation of the scientific thought of students at academic level

The importance of fluid mechanics is often underrated. Besides studying the mechanisms governing static and dynamic fluids, this discipline could have a great role in the understanding of many principles, topics and concepts of general mechanics. When approached in a proper way, fluid mechanics provides numerous 'case studies' apt to clarify the physical content of several mechanical laws. Unfortunately, fluid mechanics, in physics classes, is generally viewed as a 'lower branch' of mechanics. Its rules and laws too often are regarded as too particular, or even as special cases, to deserve the same attention paid to other arguments. The help that fluid mechanics could return in the learning process can be proved by some easy considerations. In this frame, the so-called hydrostatic paradoxes could provide a tremendous contribution to the learning processes

Les carrières politiques naissent-elles encore dans les communes ? Etat des lieux des profils politiques et parcours atypiques = Beginnen die politischen Karrieren noch immer in den Gemeinden ? : Politische Profile und atypische Laufbahnen : eine Bestandsaufnahme

Ce document présente quelques constats saillants sur l’évolution des carrières politiques des parlementaires fédéraux de 1957 à nos jours sous l’angle de la place des différents échelons fédéraux dans leur carrière politique. Notre étude a pour but d’identifier dans quelle mesure, au fil du temps, les échelons communaux et cantonaux restent des étapes importantes dans les carrières politiques fédérales. Siéger dans un organe législatif ou exécutif communal ou cantonal constitue-t-il toujours une étape indispensable pour accéder au Parlement fédéral ? Les parlementaires cumulent-ils toujours plusieurs mandats électifs ? Nous cherchons par là à proposer un bref état des lieux de l’évolution des carrières politiques des parlementaires fédéraux en nous centrant sur la « sensibilité » cantonale et communale des élus fédéraux au cours de leurs carrières depuis les années 1950. Cette analyse nous offre ainsi des constats pour penser l’évolution du fédéralisme suisse. Même si certaines ruptures peuvent être identifiées, ce sont plutôt les nombreuses continuités qui prévalent. Les données portent essentiellement sur quatre cohortes de parlementaires du Conseil national et du Conseil des Etats (1957, 1980, 2000, 2016) dont nous analysons les différentes étapes de leur carrière politique. = Das vorliegende Dokument präsentiert einige auffallende Erkenntnisse aus einer Analyse der Entwicklung der politischen Karriere der Bundesparlamentarierinnen und -parlamentarier von 1957 bis heute unter dem Blickwinkel der Bedeutung der verschiedenen föderalen Ebenen in ihrem Werdegang. Unsere Studie befasste sich mit der Frage, inwiefern die kommunalen und kantonalen Ebenen weiterhin bedeutende Etappen für eine politische Karriere auf Bundes- ebene sind. Ist ein Amt in einem legislativen oder exekutiven Organ einer Gemeinde oder eines Kantons immer noch ein unerlässlicher Schritt auf dem Weg ins Bundesparlament? Nehmen Parlamentarierinnen und Parlamentarier weiterhin mehrere politische Mandate wahr? Wir haben eine kurze Bestandsaufnahme der Entwicklung der politischen Karriere der Parla- mentsmitglieder vorgenommen und uns dabei auf die Frage konzentriert, wie sehr sich die Bundesparlamentarierinnen und -parlamentarier in ihrer Laufbahn seit den 1950er Jahren um kantonale und kommunale Belange gekümmert haben und diesbezüglich sensibilisiert sind. Diese Analyse liefert Ansätze, um über die Entwicklung des Schweizer Föderalismus nach- zudenken. Auch wenn gewisse Brüche zu erkennen sind, überwiegen eher die zahlreichen Kontinuitäten. Die untersuchten Daten betreffen im Wesentlichen vier Kohorten von Mitgliedern des Natio- nal- und Ständerates (1957, 1980, 2000, 2016), deren verschiedenen Etappen ihrer politi- schen Laufbahn einer Analyse unterzogen wurden

Electronic phase separation near the superconductor-insulator transition of Nd1+xBa2−xCu3O7−δ thin films studied by an electric-field-induced doping effect

We report a detailed study of the transport properties of Nd(1+x)Ba(2-x)Cu(3)O(7-delta) thin films with doping changed by field effect. The data cover the whole superconducting to insulating transition and show remarkable Similarities with the effect of chemical doping in high critical temperature superconductors. The results suggest that the add-on of carriers is accompanied by an electronic phase separation, independent on the details of the doping mechanism

A teaser made simple: a didactic measurement of the spectral answer of a human-eye-calibrated lux meter

A simple didactic experiment has been designed and realized, in order to illustrate to undergraduate students in scientific faculties some basic concepts lying behind the fundamentals of geometrical optics. The spectral response of a human-eye-calibrated lux meter was measured using a very trivial experimental arrangement. The white light of a halogen lamp was decomposed into its spectral components through a diffraction grating, so that collecting the radiation at different dispersion angles allowed one to measure the intensity as a function of wavelength. The experiment can be used to effectively illustrate the concepts of spectral distribution, the radiometry versus photometry conversion and photopic response, and the famous historical experience by Herschel on the 'temperature of colours'

Синтез слоев графена из рисовой шелухи и их характеристики

In this work, a method of obtaining graphene layers from natural source specifically from rice husk was developed. A rice husk (RH) was used as a raw material, and potassium hydroxide was used as activation agent. The graphene layers were obtained after four successive stages: pre-carbonization, desilication in 1M NaOH solution, chemical activation and exfoliation of the carbonized rice husk (CRH). The obtained samples were studied using Raman spectroscopy, TEM and SEM; the Raman peaks evidenced the presence of graphene multilayers in the sample. A detailed observation of Raman spectroscopy showed that the obtained samples with ratio of 1/4 and 1/5 (RH/KOH) consisted of graphene layers with a high content of amorphous component. The yield of the product was ~ 3% by weight. This study can provide a new way to the large-scale synthesis of low-cost single and multi-layered graphene using rice husk or other renewable resources

THz spectroscopy on graphene-like materials for bio-compatible devices

Graphene-like (GL) layers and eumelanin-based graphene-like (EUGL) hybrids have been investigated through THz time domain spectroscopy. The interest in these materials lies on their peculiar chemical-physical properties: the former are conductive water stable materials, whereas the latter are biocompatible materials with good conductive and adhesive properties. Both exhibit promising optoelectronic and bioelectronic applications. We measured mixtures of GL layers or EUGL hybrids with KBr, shaped in pellets with uniform thickness, in order to circumvent problems related to sample inhomogeneity and roughness. A mean field theory was applied to extract direct information on permittivity and conductivity. Data have been carefully fitted through the Drude-Smith theory, confirming the conductive nature of the hybrid materials. The results show that EUGL hybrid-based devices can be promising for the next generation of printable bio-circuits