Einen Zahn zugelegt

Damit ein Zahnersatz von den Patienten und den Zahnärzten akzeptiert wird, muss das Produkt hohen ästhetischen Ansprüchen genügen. Zudem muss eine hohe Festigkeit und Zähigkeit erreicht werden, damit eine einwandfreie Funktion gewährleistet ist. Zusammen mit der Firma Straumann und der Fachhochschule Nordwestschweiz (FHNW) arbeitet die BFH an neuartigen Methoden zur Herstellung von Zahnersatz

Local Impedance Spectroscopy: A Potential Tool to Characterize the Evolution of Emulsions and Foams

The potential of local impedance spectroscopy (IS) to access changes in emulsions and foams has been investigated. As test systems we used the separation of a simple oil/vinegar mixture as well as the whipping process of dairy cream. For the latter, IS data were compared to particle size distribution (PSD) measurements. Our measurements show that local IS is indeed a valuable tool to locally study processes in emulsion. On one hand, it seems to be very sensitive to small water quantities in oil thus being a suitable method for process control in water removing processes. On the other hand, concerning fat foams, it seems to be able to detect the evolution of foam structures. Both examples show that local IS could be a helpful tool for process control

A comparison of microtensile and microcompression methods for studying plastic properties of nanocrystalline electrodeposited nickel at different length scales

A comparison of microcompression and microtensile methods to study mechanical properties of electrodeposited nanocrystalline (nc) nickel has been performed. Microtensile tests that probe a volume of more than 2 × 106 μm3 show reasonable agreement with results from microcompression tests that probe much smaller volumes down to a few μm3. Differences between the two uniaxial techniques are discussed in terms of measurements errors, probed volume and surface effects, strain rate, and influence of stress state. Uniaxial solicitation in compression mode revealed several advantages for studying stress–strain properties

Mikrotechnik in der Gemälderestaurierung

Als vielversprechender Ersatz für herkömmliche Klebetechniken in der Konservierung und Restaurierung von Gemälden gelten Klebstoffgitter. Die Dimensionen der Gitter betragen wenige Hundert Mikrometer. Etablierte Verfahren aus der Mikrotechnik könnten deshalb zur Herstellung solcher Gitter genutzt werden

Murviel-lès-Montpellier – Le Mas d'Oliviers (secteur extra-muros sud-ouest), Maison de retraite 1 (parcelle 371, secteur B1)

Identifiant de l'opération archéologique : Date de l'opération : 1994 (SU) Inventeur(s) : Schwaller Martine (SRA) Le projet d'installation d'une maison de retraite médicalisée sur un terrain situé au sud de l'enceinte et à côté du stade a entraîné une étude d'impact archéologique dans l'angle sud-est de la parcelle 371 [ (Fig. n°1), site E]. Les tranchées d'exploration ont mis au jour, d'une part, le tracé fossile d'un cours d'eau orienté est-ouest (peut-être un ancien lit du Carabiol), d'au..

A novel Model for the Mechanism of Laser-Induced Back Side Wet Etching in Aqueous Cu Solutions using ns Pulses at 1064nm

Laser induced back side wet etching has shown to be a promising tool for the micro-structuring of transparent materials. Detailed studies have been performed using UV excimer laser sources, aromatic hydrocarbon and liquid metal absorbers. Only little work is reported however using aqueous Cu solutions as absorbers and ns laser pulses at 1064 nm wavelength. We present a novel model for this specific setup. Our experiments indicate that physisorbed Cu2+ ions at the polar glass surface absorb the laser light. This leads to local thermal stresses in the glass and subsequent micro-ablation

Nanoindentation of single pulp fibre cell walls

Unrefined chemical pulps of bleached and unbleached softwood (Scots pine, Pinus sylvestris) and hardwood (Eucalyptus, Eucalyptus globulus) were subjected to indentation tests using a nanoindenter equipped with an AFM scanner. Tests on unbleached pulps revealed no difference in hardness values between softwood and hardwood, but bleaching treatment decreased the hardness values of both pulps. Indentation modulus of 12GPa was observed for unbleached softwood pulps, which is 25% higher than unbleached hardwood pulps. Bleaching treatment again decreased the indentation modulus of the softwood pulps, whereas it slightly increased the indentation modulus of the hardwood pulps. After bleaching and drying processes, only negligible difference was observed in cell wall mechanical properties (hardness and indentation modulus) between hardwood and softwood pulps. This study is based on latewood pulp fibre

Comparison of nanoindentation results obtained with Berkovich and cube-corner indenters

There is increasing interest in using sharp cube corner indenters in nanoindentation experiments to study plastic properties. In combination with finite element methods it is for instance possible to extract stress-strain curves from load-displacement curves measured with differently shaped pyramidal indenters. Another example is the fracture toughness of coatings, which can be studied using cracks produced during indentation with cube corner tips. We have carried out indentation experiments with Berkovich and cube corner indenters on eight different materials with different mechanical properties. To gain information about the formation of pile-up and cracks, indentation experiments with cube corner indenter were performed inside a Scanning Electron Microscope (SEM) using a custom-built SEMMicroindenter. The results show that reliable hardness and modulus values can be measured using cube corner indenters. However, the fit range of the unloading curve has a much bigger influence on the results for the cube corner than for the Berkovich tip. The unloading curves of a cube corner measurement should therefore be carefully inspected to determine the region of smooth curvature and the unloading fit range chosen warily. Comparison of the modulus results shows that there is no significant difference between cube corner and Berkovich measurements. Also for hardness, no fundamental difference is observed for most of the investigated materials. Exceptions are materials like silicon nitride, cemented carbide or glassy carbon, where a clear difference to the hardness reference value has been observed although the modulus difference is not pronounced

Micro structuring of transparent materials with NIR ns-laser pulses

A current challenge in laser processing is high precision micromachining of transparent materials, e.g. to manufacture micro-optical elements. This can be achieved amongst others by using laser induced backside wet etching. Research has been done by several groups in the last years. Most of the published results were obtained by using UV excimer lasers. Our approach deals withthe implementation of the technique for NIR laser sources. We investigated the effects of different pulse widths and repetitionrates on laser induced back side wet etching for 1064nm wavelength and for different absorbers

AgO investigated by photoelectron spectroscopy : Evidence for mixed valence

We present photoelectron spectroscopy investigations of in-situ prepared AgO. The sample was prepared by room temperature oxidation of Ag in an electron cyclotron resonance O2 plasma. In contrast to other measurements based on ex situ prepared AgO powder samples, our investigations show a distinct double peak structure of the O 1s signal with a remarkable chemical shift of 2.9 eV between the two O 1s components. These two components can not be motivated from a crystallographic point of view as the oxygen sites are all equivalent in the unit cell. We interpret this double peak structure as a characteristic feature of AgO and discuss it in terms of mixed valences