ZIAF — Audit für landwirtschaftliches Subventionsverfahren

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Chemical and Morphological Changes of Vacuum-Plasma-Sprayed Hydroxyapatite Coatings during Immersion in Simulated Physiological Solutions

The purpose of this investigation was to study the behavior of vacuum-plasma-sprayed hydroxyapatite (VPS-HA) coatings in a defined simulated physiological environment that mimics the conditions that the material experiences after implantation in the human body. Commercially available and clinically used HA coatings on titanium alloy substrates were immersed in an inorganic simulated body fluid (SBF) with ion concentrations that were almost equal to those of human blood plasma and in fetal calf serum (FCS) for time periods of 1, 3, 7, 14, and 28 days. At each time interval, the VPS-HA coatings were analyzed using scanning electron microscopy, X-ray diffractometry, Fourier transform infrared spectroscopy, and inductively coupled plasma-atomic emission spectroscopy. The as-received VPS coatings consisted of HA as the main phase component; in addition, small concentrations of tricalciumphosphate (TCP) were determined to be present. During immersion in SBF, transformation of the peripheral area of the VPS coating to a regular spherical shape was observed. Concentration measurements of the immersion solution indicated that dissolution of the more-soluble TCP started within the first day. At the same time, precipitation of a carbonate-containing, marginally crystalline calcium phosphate with very small coherently scattering domains was observed. In FCS, the dissolution of calcium and phosphorus was observed; however, the precipitation of the new calcium phosphate layer was retarded by the presence of proteins, which indicates their important role in the ion-exchange mechanisms. In both solutions, the coating integrity was not adversely affected, which indicates the high stability of VPS-HA coatings in a simulated physiological environment.     

Analysis of short fibres orientation in steel fibre-reinforced concrete (SFRC) by X-ray tomography

The mechanical properties of fibre composite materials are largely determined by the orientation of fibres within the matrix. Which orientation distribution short fibres follow in different parts of a structural element is still a subject for research and discussions in the scientific community. In this article, we present a modern and advanced method for measuring the orientation of short fibres in steel fibre-reinforced concrete (SFRC) by X-ray microtomography. With this method, a voxel image of the fibres is obtained directly in 3D, and the orientation of each individual fibre is calculated based on a skeletonized representation of this image. Scans of 12 SFRC samples, taken from the central height region of real-size floor slabs, reveal the fibres to be mostly horizontally oriented near the centre of a floor slab and more vertically oriented near the edge; here the alignment with the formwork dominates. The fibre orientation distributions are characterized by several orientation parameters as quantitative measures for the alignment. On the practical side, this method has the potential to be incorporated into the development and production process of SFRC structures to verify how the fibres contribute to capacity.     

Voltage Dependence of the Amplitude of Aharonov-Bohm Oscillations in Mesoscopic Metal Rings

We investigated the influence of a DC-bias voltage V_DCon the Aharonov–Bohm oscillations in mesoscopic metal rings.The amplitude of the oscillations fluctuates as a function ofV_DC with a typical voltage scale corresponding to theThouless energy. We also observed a square-root like increaseof the amplitude with increasing V_DC. This behavior is inagreement with the theoretical prediction of the fluctuationsof the nonlinear conductance in singly connectednanostuctures.     

使用有无定型载体的催化剂的乙醇过程

正本发明涉及到有无定型载体和一种或几种活性金属的催化剂,以及使用这一催化剂从醋酸生产乙醇的过程。无定型载体可以包含载体材料和无定型载体改性剂,改性剂调节载体材料的酸度。在无定型催化剂     

改进载体制备的加氢催化剂的煅烧

正本发明涉及到有非晶型型载体和一种或多种活性金属的催化剂。非晶型载体可能包括载体材料和非晶型载体改性剂,改性剂调节载体材料的酸度。在非晶型催化剂制备时,后-合成处理,即煅烧,可以用于调节催化     

Experimental results of nanofluids flow effects on metal surfaces

The results of an experimental study on the effects of the flow of nanofluids (water-based suspensions of nanometer-sized solid particles) on metal surfaces are presented. Either different nanofluids (containing TiO₂, Al₂O₃, ZrO₂, and SiC, respectively) and different target materials (aluminum, copper, stainless steel) have been investigated, under similar operating conditions. Different behaviors were observed depending on the specific combination nanofluid-target material, which in some cases led to severe damaging of the tested target, thus highlighting the need for an adequate preliminary investigation of the possible interactions between the selected nanofluid and the apparatus materials, before its adoption as heat transfer fluid.