Filtern
Dokumenttyp
Schlagworte
- Analysis (1)
- Calorimetry (1)
- Cement (1)
- Computertomographie (1)
- Cyanine (1)
- Diffuse (1)
- Dye (1)
- Fluorescence (1)
- Holzschutz (1)
- Kulturgut aus Holz (1)
- Measurement uncertainty (1)
- Messunsicherheit (1)
- Method (1)
- Monitoring (1)
- Nano (1)
- Optical probe (1)
- Optical spectroscopy (1)
- PCE (1)
- Particle (1)
- Phase (1)
- Reflection (1)
- Sensor (1)
- Simulation (1)
- Virtual metrology (1)
- Virtuelle Messtechnik (1)
- XRD (1)
Organisationseinheit der BAM
Die Mikro- und Nanotechnologie gehört zu den Schlüsseltechnologien des 21. Jahrhunderts mit hohen Wachstumsprognosen, wie auch die im Auftrag des BMBF durchgeführte Studie “Nanotechnologie als wirtschaftlicher Wachstumsmarkt” von 2004 ausführlich darstellt. Aus diesem Trend resultiert ein steigender Bedarf an Messsystemen, die Nanostrukturen prozessnah bzw. im Fertigungsprozess charakterisieren können. Virtuelle Messgeräte liefern Erkenntnisse zur Entwicklung neuartiger Messsysteme, Analyse und Optimierung bestehender Verfahren sowie die Bestimmung der Messunsicherheit und modellbasierten Korrektur systematischer Fehler. Der virtuelle Messprozess umfasst neben dem Messmittel auch die Probe und die Wechselwirkungen zwischen beiden. In diesem Beitrag werden virtuelle Messgeräte vorgestellt sowie deren Anwendung diskutiert.
Polycarboxylate ethers (PCEs) are widely used in construction, but the exact nature of their interaction with cement is still debated. Aiming at a better understanding of the role of tricalcium Aluminate (C3A) in cement hydration, we assessed the potential of optical spectroscopy in combination with a water-soluble fluorescent organic reporter dye (S0586) to monitor the early hydration of C3A in the presence of 26 wt% CaSO4.2H2O (C3A26G-S) with and without PCE. As optical methods, steady-state fluorescence and diffuse reflectance (UV–VisDR) spectroscopy were employed. Phase characterization and particle size distribution were performed with in-situ X-ray diffraction (in-situ XRD) and dynamic light scattering (DLS). Our results show that fluorescence and UV–VisDR spectroscopy can be used to monitor the formation of metastable phases by the disaggregation of the dye S0586 in a cement paste as well as changes in ettringite formation. Addition of PCE slowed down the disaggregation of the dye as reflected by the corresponding changes of the dyes absorption and fluorescence. This prolonged induction period is a well-known side effect of PCEs and agrees with previous reported calorimetric studies and the Inhibition of gypsum dissolution observed by in-situ XRD. This demonstrates that fluorescence and UV–VisDR spectroscopy together with a suitable optical probe can provide deeper insights into the influence of PCE on C3A-gypsum hydration which could be e.g., utilized as screening method for comparing the influences
of different types of PCEs.
The baroque epitaph Reyer (1704) at the St. Laurentius church in Tönning was treated with carbolineum as a wood preservation agent in 1903. The subsequent constant migration of carbolineum through the layers of paint to the surface has had a detrimental effect on the aesthetic appearance of the epitaph. Carbolineum is an oily, water-insoluble, flammable, dark brown mixture of coal tar oil components. Due to its content of polycyclic aromatic hydrocarbons (PAH), which are classified as carcinogenic and harmful to the environment, the use of carbolineum has been forbidden. The aim of the project is to develop an exemplary Conservation treatment (hat will reduce the toxic contents of the historical wooden object. The new method should be applicable to similar objects that are also contaminated with carbolineum. The historic carbolineum was identified by the GC-MS method and the X-Ray computed tomography revealed the biological wood damage and previous restoration measures. Several decontamination methods such as the extraction with supercritical C02, with dichloromethane vapour/fluids, with 1,3-dioxolane or with petrol ether by vaccum impregnation were investigated. This project is founded by the Deutsche Bundesstiftung Umwelt (DBU).
Digital image analysis
(2011)
Comparatiye digital analysis was performed on the five moon drawings from the New York copy of the Sidereus Nuncius and the copperplate etchings printed in the Graz and Florence copies. The sequences of figures for the drawings on pages 8r, 9v and lOv demonstrate the process of digitally enhancing the black material on the drawings, isolating that material and then overlaying it on the etchings. Using an image editing program (Image Pro® Plus by Media Cybernetics) the black material on the drawings and the letterpress-printed text were isolated and segmented from the brown drawing media. As shown in Figs. 4, 6 and 8, the isolation was possible and the black material clearly overlaps the demarcation line in the drawings. To compare the drawn and printed images of each moon, the images were laid on top of each other with Adobe Photoshop® (Adobe Systems). In these images, the printed text was used for alignment and scale. By decreasing the opacity of the image on top, the lines of each image were compared. This technique revealed an almost one-to-one correlation between the demarcation line in the drawing (as indicated by the black material) and that on the etching. In each case, the similarities and concurrences by far outnumbered the minor deviations in line. One precondition of this work was that all the photographs be at the same angle, plane-parallel, so that the drawings could be compared with the etchings. A slight aberration in the plane could distort the geometry of the illustrations. Rectification of the image plane was carried out by means of the program metigo® MAP 2.2 (Fokus GmbH Leipzig). To validate the method, photographs from the same detail of the New York copy taken with different photographic cameras and different Parameters were rectified with metigo® MAP and compared in Adobe Photoshop®. The overlay of these photographs shows a good correlation in the layout of the lettering and moon figures with only small aberrations. The distribution of the black material on the drawings can be followed as clearly in the rectified photographs as in the unrectified photographs, the information is the same.