Rechtliche Grenzen gebührenpolitischer Steuerung: das Beispiel der Abfallgebühren

Umweltrechtliche Regulierung bedient sich - auch unter europarechtlichem Einfluss - verstärkt ökonomischer Instrumente. Im Bereich des Abfallrechts wurde in diesem Zusammenhang lange über die Möglichkeiten und Grenzen kommunaler Verpackungssteuern gestritten. In jüngerer Zeit sind kommunale Abfallgebühren in den Fokus der Aufmerksamkeit gerückt. Ihre Ausformung bewegt sich in einem Spannungsverhältnis allgemeiner gebührenrechtlicher Grundsätze (Kostendeckungsprinzip), verfassungsrechtlicher Prinzipien (Verhältnismäßigkeitsprinzip, Gleichheitsgrundsatz), landesgesetzlicher Vorgaben und kommunaler Satzungshoheit. Vor diesem Hintergrund stellt sich die Frage, inwieweit Abfallgebühren im Spannungsfeld dieser Vorschriften Vermeidungsanreize enthalten und hierdurch Bestandteil eines Abgabenregulierungsrechts werden können.Environmental governance is - not least as a result of European Union legislation - increasingly based on economic instruments. In the field of waste policy long-winded political debates on the introduction of packaging waste charges have been a case in point. More recently, the political attention has shifted to local waste charges. The specification of the latter occurs within a complex framework of general legal principles related to fee collection (like the principle of cost recovery), constitutional principles (principles of proportionality and equality), federal law, as well as local statutes. Against this backdrop, the central problem addressed by this article refers to the question if and to what extent waste charges may actually entail incentives for waste avoidance and this way might constitute an elementary cornerstone of national waste governance

Cyclic deformation behavior of Mg–SiC nanocomposites on the macroscale and nanoscale

Metal‐ceramic nanocomposites are promising candidates for applications necessitating light weight and excellent fatigue resistance. We produced Mg–SiC nanocomposites from mechanically milled powders, yielding a homogeneous nanocrystalline structure and excellent quasistatic strength values. Little is known, however, about the fatigue behavior of such composites. Here, we used load increase tests on the macroscale to yield estimation values of the fatigue endurance limit. Fatigue strength increased significantly for the materials processed by the powder metallurgical route. We further investigated the cyclic deformation behavior under stress‐controlled conditions on the macroscale and nanoscale. Cyclic nanoindentation showed that indentation depth and cyclic plastic deformation decreased with increasing reinforcement content, hinting to a higher cyclic strength and corroborating the results from the macroscopic load increase tests. Our results therefore show that cyclic nanoindentation reliably determines the plastic deformation behavior of Mg nanocomposites offering the possibility of fast material analysis.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Peer Reviewe

Kommunikationsunterricht im Ingenieurstudium - Quo vadis?

Der Artikel stellt den Ansatz eines sprachübergreifenden und szenariobasierten Kommunikationsunterrichts an der School of Engineering vor. Ausgehend von gesellschaftlichen und hochschulstrategischen Überlegungen werden die für den Unterrichtsansatz zentralen Elemente der Mehrsprachigkeit, des szenariobasierten Lernens und der Digitalisierung diskutiert. Darauf aufbauend wird die Durchführung und Auswertung eines Pilotversuchs zum sprachübergreifenden und szeanriobasierten Unterricht im Studiengang Wirtschaftsingenieurwesen erläutert

Szenariobasierter Kommunikationsunterricht an Fachhochschulen

The role of language teaching in technical curricula finds itself today at a crossroads. First and foreign language training per se are less a priority than is communicative competence in a professional and scientific environment. A project team at the ZHAW School of Engineering has therefore embarked on the design of a functionally defined, scenario-based learning concept within a communication curriculum in which the roles of the two languages, German and English, are understood as complementary and even profitably engaged in the same classroom and as part of one learning experience

Auto-completion of Contours in Sketches, Maps and Sparse 2D Images Based on Topological Persistence

We design a new fast algorithm to automatically complete closed contours in a finite point cloud on the plane. The only input can be a scanned map with almost closed curves, a hand-drawn artistic sketch or any sparse dotted image in 2D without any extra parameters. The output is a hierarchy of closed contours that have a long enough life span (persistence) in a sequence of nested neighborhoods of the input points. We prove theoretical guarantees when, for a given noisy sample of a graph in the plane, the output contours geometrically approximate the original contours in the unknown graph

Forage silica and water content control dental surface texture in guinea pigs and provide implications for dietary reconstruction

Recent studies have shown that phytoliths are softer than dental enamel but still act as abrasive agents. Thus, phytolith content should be reflected in dental wear. Because native phytoliths show lower indentation hardness than phytoliths extracted by dry ashing, we propose that the hydration state of plant tissue will also affect dental abrasion. To assess this, we performed a controlled feeding experiment with 36 adult guinea pigs, fed exclusively with three different natural forages: lucerne, timothy grass, and bamboo with distinct phytolith/silica contents (lucerne < grass < bamboo). Each forage was fed in fresh or dried state for 3 weeks. We then performed 3D surface texture analysis (3DST) on the upper fourth premolar. Generally, enamel surface roughness increased with higher forage phytolith/silica content. Additionally, fresh and dry grass feeders displayed differences in wear patterns, with those of fresh grass feeders being similar to fresh and dry lucerne (phytolith-poor) feeders, supporting previous reports that "fresh grass grazers" show less abrasion than unspecialized grazers. Our results demonstrate that not only phytolith content but also properties such as water content can significantly affect plant abrasiveness, even to such an extent that wear patterns characteristic for dietary traits (browser-grazer differences) become indistinguishable

Dust and grit matter: abrasives of different size lead to opposing dental microwear textures in experimentally fed sheep (Ovis aries)

External abrasives ingested along with the herbivore diet are considered main contributors to dental wear, though how the different sizes and concentrations of these abrasives influence wear remains unclear. Dental microwear texture analysis (DMTA) is an establishedmethod for dietary reconstructionwhich describes a tooth’s surface topography on a micrometre scale. The method has yielded conflicting results as to the effect of external abrasives. In the present study, a feeding experiment was performed on sheep (Ovis aries) fed seven diets of different abrasiveness. Our aim was to discern the individual effects of size (4, 50 and 130 μm) and concentration (0%,4% and 8% of dry matter) of abrasives on dental wear, applying DMTA to four tooth positions. Microwear textures differed between individual teeth, but surprisingly, showed no gradient along the molar tooth row, and the strongest differentiation of experimental groups was achieved when combining data of all maxillary molars. Overall, a pattern of increasing height, volume and complexity of the tooth’s microscopic surface appeared with increasing size of dietary abrasives, and when compared with the control, the small abrasive diets showed a polishing effect. The results indicate that the size of dietary abrasives is more important for dental microwear texture traces than their concentration, and that different sizes can have opposing effects on the dietary signal. The latter finding possibly explains conflicting evidence from previous experimental DMTA applications. Further exploration is required to understand whether and how microscopic traces created by abrasives translate quantitatively to tissue loss