Refine
Document Type
Language
- English (3)
Reviewed
- Begutachtet/Reviewed (3) (remove)
Keywords
Institute
Carbon-doped titania was fabricated via carbothermal treatment in nitrogen–acetylene gas flow and further used as a precursor for multiwalled titanate nanotube (TNT) synthesis via alkaline hydrothermal route. Investigation of the reaction products after hydrothermal treatment of carbon-doped titania using Transmission electron microscopy, X-ray diffraction, and Brunauer–Emmett–Teller method shows the successful formation of TNTs. The presence of carbon was proved although the type of incorporation could not be certified. All samples show approximately the same carbon content before and after hydrothermal treatment. An increasing pretreatment temperature of titania precursor powders yields more secondary products in the nanotube samples, indicating lower reactivity of the titanium oxycarbide phase during hydrothermal treatment. In this study, TNTs with 6 wt% carbon and with the highest specific surface area of 340 m2/g were formed via hydrothermal treatment of carbon-doped titania precursor powder exposed to 700 °C during carbothermal pretreatment.
Highly connected with the environment via various interfaces, cars have been the focus of malicious cyber attacks for years. These attacks are becoming an increasing burden for a society with growing vehicle autonomization: they are the sword of Damocles of future mobility. Therefore, research is particularly active in the area of vehicle IT security, and in part also in the area of dependability, in order to develop effective countermeasures and to maintain a minimum of one step ahead of hackers. This paper examines the known state-of-the-art security and dependability measures based on a detailed and systematic analysis of published cyber attacks on automotive software systems. The sobering result of the analysis of the cyber attacks with the model-based technique SAM (Security Abstraction Model) and a categorization of the examined attacks in relation to the known security and dependability measures is that most countermeasures against cyber attacks are hardly effective. They either are not applicable to the underlying problem or take effect too late; the intruder has already gained access to a substantial part of the vehicle when the countermeasures apply. The paper is thus contributing to an understanding of the gaps that exist today in the area of vehicle security and dependability and concludes concrete research challenges.
Semiconducting transition metal oxides such as TiO 2 are promising photo(electro)catalysts for solar water splitting and photoreduction of CO 2 as well as for antibacterial, self-, water and air-cleaning coatings and admixtures in paints, building materials, on window glass or medical devices. In photoelectrocatalytic applications TiO 2 is usually used as photoanode only catalyzing the oxidation
reaction. In coatings and admixtures TiO 2 works as heterogeneous catalyst and has to catalyze a complete redox cycle. While photoelectrochemical charge transport parameters are usually quite well accessible by electrochemical measurements, the quantitative description of photocatalytic properties is more challenging. Here, we present a systematic structural, photoelectrocatalytic, photocatalytic and antimicrobial study to understand if and how photoelectrochemical parameters can be used to predict the photocatalytic activity of TiO 2. For this purpose TiO 2 thin films on
flourine-doped tin oxide substrates were prepared and annealed at temperatures between 200 and 600 ◦C. The film morphologies and thicknesses were studied by GIXRD, FESEM, and EDX. Photoelectrochemical properties were measured by linear sweep voltammetry, photoelectrochemical impedance spectroscopy, chopped light chronoamperometry, and intensity modulated photocurrent/photovoltage spectroscopy. For comparison, photocatalytic rate constants were determined by
methylene blue degradation and Escherichea coli inactivation and correlated with the deducedphotoelectrocatalytic parameters. We found that the respective photoactivities of amorphous and crystalline TiO 2 nanolayers can be best correlated, if the extracted photoelectrochemical parameters such as charge transfer and recombination rates, charge transfer efficiencies and resistances are measured close to the open circuit potential (OCP). Hence, the interfacial charge transport parameters at the OCP can be indeed used as descriptors for predicting and understanding the photocatalytic
activity of TiO 2 coatings.