Polymer derived ceramic materials from Si,B and MoSiB filler-loaded perhydropolysilazane precursor for oxidation protection

Silica-based coating systems were developed using polymer derived ceramics (PDCs) technology. Ceramic composites on the base of a SiO₂ and SiNO matrix and homogeneously distributed Mo₅SiB₂, SiB₆, Si and B fillers were manufactured. The coating systems have low porosity and provide a high oxidation resistance up to 100 h at 800 °C and 1100 °C in air. The influence of temperature and atmosphere of pyrolysis on the polymer precursor, the volume fraction of filler materials on the chemical composition of compacts as well as their high-temperature oxidation protection was investigated.     

Control of material flow in a combined backward can - forward rod extrusion

The paper deals with an analysis of an extrusion process with a divided material flow. As we are forced to seek for optimal technological solutions with short testing times and low risks and costs, a reliable process evaluation is of the greatest importance.

The paper discusses the influences of tool geometry, friction and lubrication as well as workpiece properties on balanced material flow in a combined extrusion process. The FEM analysis applying the DEFORM code has been used in order to predict the process parameters and to estimate its stability. The subsequent experimental verification has resulted in a conclusion that modern computer aided tools, tuned by proper experimental sets, can be used for fast and reliable cold metal forging process planning.     

Digital PCR Panel for Sensitive Hematopoietic Chimerism Quantification after Allogeneic Stem Cell Transplantation

Accurate and sensitive determination of hematopoietic chimerism is a crucial diagnostic measure after allogeneic stem cell transplantation to monitor engraftment and potentially residual disease. Short tandem repeat (STR) amplification, the current “gold standard” for chimerism assessment facilitates reliable accuracy, but is hampered by its limited sensitivity (≥1%). Digital PCR (dPCR) has been shown to combine exact quantification and high reproducibility over a very wide measurement range with excellent sensitivity (routinely ≤0.1%) and thus represents a promising alternative to STR analysis. We here aimed at developing a whole panel of digital-PCR based assays for routine diagnostic. To this end, we tested suitability of 52 deletion/insertion polymorphisms (DIPs) for duplex analysis in combination with either a reference gene or a Y-chromosome specific PCR. Twenty-nine DIPs with high power of discrimination and good performance were identified, optimized and technically validated. We tested the newly established assays on retrospective patient samples that were in parallel also measured by STR amplification and found excellent correlation. Finally, a screening plate for initial genotyping with DIP-specific duplex dPCR assays was designed for convenient assay selection. In conclusion, we have established a comprehensive dPCR system for precise and high-sensitivity measurement of hematopoietic chimerism, which should be highly useful for clinical routine diagnostics.     

Influence of temperature of thermal treatment on surface densification of spruce

Spruce (Picea abies L. Karst) wood lamellae, thermally treated at 170, 190, 210 and 230 °C were surface densified by compression at a temperature of 150 °C to three degrees of compression. Immediate springback, set recovery, mechanical properties in 3-point flexure, Brinell hardness and density profiles measurements were used to determine the effect of thermal treatment on the properties of surface densified wood. The highest immediate springback occurred in wood specimens thermally treated at the highest temperature (230 °C) and decreased with decreasing thermal treatment temperature. The untreated samples had the highest set recovery, which decreased with the temperature of thermal treatment. The surface densification increased hardness and bending strength. The highest increase was in the case of untreated wood and decreased with the temperature of thermal treatment. The modulus of elasticity (MOE) and modulus of rupture (MOR) of surface densified wood decreased with increasing thermal treatment temperature. The trend was similar for specimens which were thermally treated but not surface densified. Surface densification increased the density of the specimens in the first few millimetres below the surface. The highest density was achieved in untreated specimens and the lowest in specimens thermally treated at the highest temperature.     

Water jetting technology: an alternative in incremental sheet metal forming

This exploratory paper aims to introduce a high-speed Water Jet (WJ) as a tool for die-less Incremental Sheet Metal Forming (ISMF). First experiments indicate that in the case of Water Jet Incremental Sheet Metal Forming (WJISMF) the forming time, energy efficiency and forming accuracy are rather poor compared to ISMF with a rigid tool. However, the proposed technology brings higher process flexibility and better tools to workpiece interface conditions. For a better process characterization, the relative jet diameter is introduced, which is defined as the ratio between the WJ diameter and the blank thickness. Relevant process parameters are identified and technological windows are phenomenological defined, shoving that WJISMF can be applied as a complementary solution to ISMF with a rigid tool.     

Flächendatenbank für die hydrogeologische Karte im bayerischen Bodeninformationssystem

The hydrogeological survey of Bavaria has recently been intensified in order to produce a countrywide hydrogeological map at the scale of 1:50,000 by 2015. The spatial data will be seamfree, reflect the 3D-character of hydrogeological maps and comprehensive search functions will be available for the whole dataset. A spatial database was designed which incorporates the complex relations of rock and groundwater bodies. The underlying relational data model integrates the following main object types: propagation of the upper aquifers and surface layers, rock bodies, structural surfaces together with point data and fault lines, groundwater bodies as well as groundwater surfaces together with point data and the distribution of different types of groundwater potential. The database was developed as an ArcGISextension using the Geodatabase as a relational database. The application of this system supports the mapping process and guarantees a consistent data structure. After integration into the Bavarian Soil Information System, the hydrogeological spatial data will be available for the users in a searchable format.