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- 2011 (4) (entfernen)
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- Carbon nanofibers (1)
- Concealed infestation (1)
- Detection technologies (1)
- Dry rot (1)
- Electrical conductivity (1)
- Epoxy composites (1)
- Experiments (1)
- Fungal detection (1)
- Hydrogen detection (1)
- Hydrogen safety (1)
Carbon nanofibers (CNFs) were functionalized by a multistage process including oxidation, reduction and silanization. The chemical modifications were examined by Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry, Raman spectroscopy and thermogravimetric analysis. The silanized CNFs were then added into an epoxy resin (EPON 828) to study the effect of the surface modification of CNFs on the properties of nanocomposites. For comparison, nanocomposites containing original unmodified CNFs were also investigated. Scanning electron microscopy indicates better dispersion of modified fibers in the epoxy polymer matrix; the mechanical and thermal properties of composites are also improved; the electrical conductivity of the composites is reduced.
In the area of hydrogen safety, research facilities are essential for the experimental investigation of relevant phenomena, for testing devices and safety concepts, as well as for the generation of validation data for the various numerical codes and models. Within the framework of the European HySafe Network of Excellence (NoE), the 'Integration of Experimental Facilities (IEF)' activity has provided basic support for joint experimental work. Even beyond the funding period of the HySafe NoE in the 6th Framework Program, IEF represents a long-lasting effort for the sustainable integration of experimental research capacities and expertise of the partners from different research fields. In order to achieve a high standard in the quality of experimental data provided by the partners, emphasis was put on the know-how transfer between the partners. On the one hand, documentation on the experimental capacities was prepared and analyzed. On the other hand, a wiki-based communication platform was established, supported by biannual workshops covering topics ranging from measurement technologies to safety issues. Based on the partners' contributions, a working document was created on best practice including the joint experimental knowledge of all partners with regard to experimental set-ups and instrumentation. The paper gives an overview of the IEF partners and the network activities over the last five years.
Hydrogen sensors - A review
(2011)
Hydrogen sensors are of increasing importance in connection with the development and expanded use of hydrogen gas as an energy carrier and as a chemical reactant. There are an immense number of sensors reported in the literature for hydrogen detection and in this work these sensors are classified into eight different operating principles. Characteristic performance parameters of these sensor types, such as measuring range, sensitivity, selectivity and response time are reviewed and the latest technology developments are reported. Testing and validation of sensor performance are described in relation to standardisation and use in potentially explosive atmospheres so as to identify the requirements on hydrogen sensors for practical applications.
During their growth on wood many fungi produce characteristic volatile organic compounds as secondary metabolites. These microbial volatile organic compounds (MVOCs) can be used as indicators of fungal growth even when such growth is concealed. In order to investigate the formation of these volatile metabolites on building materials, specimens of pine sapwood on agar media colonized by the dry-rot fungus Serpula lacrymans and a mixture of six moulds were examined. MVOCs from this fungal growth were studied over a period of up to half a year by ion mobility spectrometry (IMS) headspace analysis using a sensitive, portable IMS mini-device. The IMS headspace spectra from the growing fungal specimens obtained during this time span are differed from non-incubated wood specimens and indicate the presence of a mixture of MVOCs. The composition and amount of volatile metabolites of the fungi changed during cultivation. This was confirmed by a principal component analysis (PCA). Identification of different MVOCs in the headspace according to drift time and the mobility of ionized gaseous species in reference to GC-MS investigations were proposed. It was concluded that IMS can be used as a rapid and sensitive on-site method to indicate actively growing fungi concealed within wood.