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- LC-MS/MS (3)
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- PCR (3)
- SC16 (3)
- Animal species differentiation (2)
- Creep deformation (2)
- ELISA (2)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (6)
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- 1.5 Proteinanalytik (4)
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- 5.1 Mikrostruktur Design und Degradation (1)
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Specimens of single crystal superalloy SC16 were creep deformed at 1223 K along [0 0 1] up to ±0.5% creep strain using stresses of -150 MPa and +150 MPa, respectively. Line widths and peak positions of superlattice reflections were measured by means of X-ray diffraction parallel and perpendicular to the load axis in the temperature range between 293 K and 1173 K. The line widths were found to decrease with the increase of temperature for both directions on the two specimens after tensile and compressive creep deformation. After both kinds of creep deformation the crystal lattice showed tetragonal distortion which decreased with increasing temperature. The tetragonality after tensile creep deformation was larger than unity while it was smaller than unity after compressive creep deformation. The peak positions and widths restored after cooling back to room temperature. The experimental results can qualitatively be explained by the creation of dislocations during deformation and their anisotropic arrangement at the γ/γ' interfaces.
Investigation of the orientation relationships of carlsbergite in the North Chile iron meteorite
(2005)
Calculation of the activation energy of self-diffusion in aluminium from impurity diffusion date
(1975)
High-resolution diffraction using synchrotron x-ray radiation was applied to study γ´ precipitates with an L12 superlattice crystal structure in the single crystal superalloy SC16 after creep deformation at 1223 K with a creep strain of ±0.5% for tensile and compressive loads, respectively. The measurements of full width at half maximum (FWHM) of 001 and 100 γ´ superlattice reflections were performed at various temperatures from ambient temperature to 1173 K in vacuum. The experimental results revealed that the FWHM of both reflections decrease with increasing temperature. It is well-known that changes in particle size and lattice distortion in materials could lead to a variation of FWHM. The observed behaviour is discussed in the light of both the above-mentioned aspects. The decrease in the peak width is mainly attributed to the temperature dependence of the internal strain state.
To start the large-scale deployment of offshore wind in German waters, the German Federal Ministry for the Environment (BMU) supports the offshore test site "alpha ventus" in the North Sea with a research budget of about 50 million Euro in the next years. The overall objective of the research is to reduce the costs of offshore wind energy deployment in deep water. In order to provide all participating research projects with detailed data, the test site will be equipped with extensive measurement instrumentation.
This research initiative was named RAVE Research at Alpha VEntus and consists of a variety of projects in connection with the installation and operation of alpha ventus. As part of the RAVE initiative, so far the participating institutes and companies have prepared projects on the following topics:
Realization of the joint measurements and data management
Analysis of loads, modelling and further development of the different components of offshore wind turbines
Loads at offshore foundations and structures
Further development of LIDAR wind measuring techniques
Grid integration of offshore wind energy
Monitoring of the offshore wind energy deployment in Germany "Offshore WMEP"
Measurement of the operating noises and modelling of the sound propagation between tower and water
Ecologic research
Time dependence of y/y' Lattice Mismatch in Creep-deformed Single Crystal Superalloy SC16 at 1173 K
(2007)
The crystallographic orientation of carlsbergite (CrN) in the north Chile meteorite (hexahedrite) was investigated using electron backscatter diffraction and transmission electron microscopy. These studies examined the CrN crystals in the rhabdites (idiomorphic schreibersite) and in kamacite. It was found that the CrN crystals embedded in rhabdite show a number of different orientation relationships with the host crystals. These orientations can be explained based on the lattice dimensions of both coexisting crystalline materials. It was also found that both carlsbergite and kamacite are characterized by a high dislocation density (109 cm2) while rhabdite is free of dislocations. It is supposed that in spite of the deformed metallic matrix, a general connection between the orientation relation of all the phases involved exists.
In the present work, electron backscatter diffraction was used to determine the microscopic dislocation structures generated during creep (with tests interrupted at the steady state) in pure 99.8% aluminium. This material was investigated at two different stress levels, corresponding to the power-law and power-law breakdown regimes. The results show that the formation of subgrain cellular structures occurs independently of the crystallographic orientation. However, the density of these cellular structures strongly depends on the grain crystallographic orientation with respect to the tensile axis direction, with <111> grains exhibiting the highest densities at both stress levels. It is proposed that this behaviour is due to the influence of intergranular stresses, which is different in <111> and <001> grains.
Formalin-fixed paraffin-embedded (FFPE) specimen from biopsy materials are a widespread sample format for pathologists and medical researchers. Pathologists are archiving vast numbers of FFPE samples which can be stored for decades. Conventional immunohistochemical staining (IHC) of biomarkers on FFPE tissue sections is one of the most important analytical techniques for cancer diagnosis and pathology in general. However standardization for IHC samples and quality management is tedious and differs significantly from clinic to clinic. Combining established IHC staining strategies with modern mass spectrometry mediated methods would increase it`s potential and enable access of large FFPE archives for multiplexed quantitation purposes. In this work element mass spectrometry and a new ink-jet printed internal standardization approach was successfully combined with IHC staining to facilitate quantitative multiplex assays for archived FFPE samples. The printing strategy improves elemental image resolution and reproducibility of paraffin embedded breast cancer tissue sections in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) using conventional IHC staining as a model system to investigate the new capabilities of this technique. For the internal standardization we applied a conventional CD-ink-jet printer to print a metal spiked ink onto the top of thin layer tissue sections with constant density. Printing was carried out in a direct comparison to an iodination of the tissue section as previously described as an alternative standardization method. The use of the printed internal standard allowed correction of the fluctuation during the laser ablation process and compensated instrumental drift effects. Mediated by the ink correction approach we achieved better signal-to-background-ratios (SBR) of 74 and better spatial resolution of 30 µm compared to iodination (SBR=23). This improved performance was demonstrated on tumorous areas in FFPE breast cancer tissue sections and allowing detection of Her-2 in tumorous areas of this tissue with significantly improved contrast.
In the field of animal species differentiation, work on standardizing methods has been intensified in Germany in recent years, not least due to the horsemeat scandal in 2013. Even though there are now hardly ever any positive findings anymore in examinations to detect horse adulterations in foods such as lasagne, animal species differentiation altogether ranks high in detecting adulteration of foods. This article, therefore, summarises the current status of analytical techniques used in Germany with standardization at German level. It has been established by the working group "Biochemical and Molecular Biological Analytics" of the Lebensmittelchemische Gesellschaft (Food Chemistry Society within the German Chemical Society) with support of experts in the working group “Molecular biology techniques for differentiating plant and animal species" (§64 of the German Food and Feed Code - LFGB) and the "Immunology and molecular biology" task force of the food hygiene and food of animal origin working group (ALTS), both from Germany.
High- and medium-entropy alloys (HEAs) are a quite new class of materials. They have a high potential for applications from low to high temperatures due to the excellent combination of their structural properties.
Concerning their application as components; processing properties, such as machinability, have hardly been investigated so far. Hence, machinability analyses with a focus on the influence of the milling process and its basic parameters (cutting speed, feed per cutting edge) on the resulting surface integrity of specimens from an equiatomic high- (CoCrFeMnNi) and a medium- (CoCrNi) entropy alloy have been carried out. A highly innovative milling process with ultrasonic assistance (USAM) was compared to conventional milling processes.
Recent studies have shown that USAM has a high potential to significantly reduce the mechanical load on the tool and workpiece surface during milling. In this study, the basic machining and ultrasonic parameters were systematically varied. After machining, the surface integrity of the alloys was analyzed in terms of topography, defects, subsurface damage, and residual stresses. It was observed that USAM reduces the cutting forces and increases the surface integrity in terms of lower tensile residual stresses and defect density near the surfaces for the CoCrFeMnNi alloy. It was shown that the cutting forces and the metallurgical influence in the sub surface region are reduced by increasing the cutting speed and reducing the feed rate per cutting edge. With the CoCrNi alloy, the tool revealed severe wear. As a result, for this alloy no influence of the parameters on the machinability could be determined.
The electron backscatter diffraction (EBSD) technique is used to investigate the dislocation structures formed after steady-state creep deformation of an Al-3.85%Mg alloy. This material is crept at two different stress levels, corresponding to the so-called power-law and power-law breakdown regimes. The results show that, regardless of the creep stress level, the strain tends to localize, leading to the formation of intragranular bands. The thickness of such bands is larger when the material is tested at loads corresponding to the power-law breakdown. This suggests enhanced diffusion by dislocation pipes.
Remote sensing of hazardous substances is a key task that can be achieved with the help of remotely operated platforms equipped with specific sensors. A huge variety of methods and used vehicles have been developed for different purposes in recent years. The term smart dust refers to a science fiction novel and develop shortly after into a research proposal at UC Berkley funded by DARPA. Subsequently, the topic gained attraction but was overall considered as to complex for the technologies available at that time. In the launched passive smart dust project, we shift to a simple “chemical intelligent” passive sensor particle on the ground combined a read-out active sensor attached to an Unmanned Aerial Vehicle (UAV). The reactive particle surface can be preadjusted in the lab for exact desired properties regarding certain reactions to hazardous substances.
Moreover, the aimed interaction with the active sensor can be modified. Planed applications allow for different materials e.g., for short time measurement, being ecologically degradable, or weather stable for long time monitoring.
High demand for remote sensing of hazardous substances. Possible solution: Use of distributed, low cost, and environmentally safe particles as passive sensors that can be read out remotely
Chemical intelligence on the particle surface can be easily modified Particles enable optically quantifiable response and inference of target substances (also no maintenance or power supply required
We introduce a passive smart dust concept as a novel solution for environmental monitoring. Utilizing chemical reagents like colorimetric indicators and other chemosensors, these particles detect varying environmental conditions. We developed paper-based sensors that are both cost-effective and eco-friendly. In practical tests, these sensors, dispersed over a designated area, successfully identified hazardous substances by changing their color when exposed to acids or bases. This color change was remotely detectable using a drone-mounted color camera. The data thus obtained was processed through specialized software, accurately pinpointing areas of contamination. This method proves the efficacy and scalability of passive smart dust technology for real-time, environmentally sustainable remote sensing of hazardous materials
Nicht zuletzt bedingt durch den Pferdefleischskandal im Jahr 2013 wurden in Deutschland die Aktivitäten bei der Methodenstandardisierung im Bereich der Tierarten-Differenzierung in den vergangenen Jahren intensiviert. Wenn auch positive Befunde bei dem Nachweis von Bestandteilen aus Pferd in Lebensmitteln wie Lasagne derzeit so gut wie nicht mehr anzutreffen sind, so hat die Tierartendifferenzierung insgesamt beim Nachweis von Verfälschungen in Lebensmitteln einen hohen Stellenwert.
Diese Arbeit fasst daher den aktuellen Stand der Analytik in Deutschland mit Schwerpunkt bei der Standardisierung zusammen. Sie wurde erstellt durch die Arbeitsgruppe „Biochemische und molekularbiologische Analytik“ der Lebensmittelchemischen Gesellschaft mit Unterstützung von Experten der Arbeitsgruppe „Molekularbiologische Methoden zur Pflanzen- und Tierartendifferenzierung“ (§ 64 LFGB) sowie der ALTS-Arbeitsgruppe „Immunologie und Molekularbiologie“ (jeweils D).
Work on standardising methods in the field of animal species differentiation has been intensified in Germany in recent years, not least due to the horsemeat scandal in 2013. Even though there are now hardly ever any positive findings any more in examinations to detect horse adulterations in foods such as lasagne, animal species differentiation altogether ranks high in detecting adulteration of foods. This article therefore summarises the current status of analytical techniques used in Germany with standardisation at German level. It has been established by the working group “Biochemical and Molecular Biological Analytics” of the Lebensmittelchemische Gesellschaft (Food Chemistry Society within the German Chemical Society) with support of experts in the working group “Molecular biology techniques for differentiating plant and animal species” (§ 64 of the German Food and Feed Code – LFGB) and the “Immunology and molecular biology” task force of the food hygiene and Food of animal origin working group (ALTS), both from Germany.