Wheel-flat diagnostic tool via wavelet transform

The detection and acknowledgement of signatures, for condition monitoring and fault diagnostics by wavelet transform, deserves increased attention, due to its property of variable time–frequency resolution, which overcomes limitations of classical time–frequency approaches.In the paper, a diagnostic tool is presented, based on the wavelet transform, able to detect and to quantify the wheel-flat defect of a test train at different speeds and to measure the train speed with proper accuracy. The designed diagnostic tool minimises the hardware requirements, since only one accelerometer is needed, and provides results in real time.The results, achieved by an exhaustive experimental campaign, permit to validate the effectiveness of the diagnostic tool and to demonstrate the advantages of wavelet-based detection of signatures.     

Catalytic activity of a mechanically mixed Ga2Oe/H-MFI catalyst under distance preservative conditions

The distance between active centers is the key factor in studying the activity of a gallium promoted zeolite catalyst. Special conditions, preserving the long distance between gallium and zeolite acid center (i.e. distance preservative conditions), were found in mechanically mixed catalysts. Catalyst samples were tested with the n-butane aromatization reaction under these conditions. The observed catalytic cooperation between active centers was ascribed to a bifunctional catalyst and/or a remote control mechanism.     

Uptake of Escherichia coli, Vibrio cholerae non-O1 and Enterococcus durans by, and depuration of mussels (Mytilus galloprovincialis)

The uptakes of Escherichia coli, Vibrio cholerae non-O1 and Enterococcus durans by mussels (Mytilus galloprovincialis) and the times for depuration were investigated in order to determine the most useful indicator of vibrio contamination. The mussels were maintained in tanks of static seawater contaminated with bacteria at 5 log10 CFU/ml for bioaccumulation. Depuration was carried out by circulating fresh seawater through the tanks. Each organism was presented alone and with others to mussels, at temperatures of 14 and 21 degrees C. In water contaminated with either single or mixed organisms, the bacteria accumulated rapidly in the mussels reaching high concentrations after 1 h. With both single and mixed organisms, the maximum numbers of E. coli in mussels were 6.6 log10 CFU/g at 14 degrees C and 5.4 log10 CFU/g at 21 degrees C. Both V. cholerae non-O1 and E. durans alone or with other organisms reached a number ranging from 6.5 to 7 log10 CFU/g at both temperatures. During depuration the numbers of all the organisms slowly decreased, with E. coli alone, numbers ranged from 2.8 to 2 log10 CFU/g after 72 h at both 14 and 21 degrees C, and the organisms were undetectable after 144 h. With mixed organisms at 14 degrees C E. coli became undetectable after 168 h but at 21 degrees C no E. coli were recovered after 72 h. At 14 degrees C V. cholerae non-O1 alone also was undetectable after 168 h, but at 21 degrees C and with mixed organisms at both temperatures. V. cholerae was recovered after 168 h at numbers about 1 log10 CFU/g. After 168 h numbers of E. durans alone ranged from 2.6 log10 CFU/g at 14 degrees C to 1.5 log10 CFU/g at 21 degrees C, and with mixed organisms the numbers ranged from 2.3 to 2.0 log10 CFU/g at both temperatures. Of the three bacteria of faecal origin, E. durans is quickly acquired by mussels and released more slowly than the others, while E. coli quickly becomes undetectable. The results suggest that, for this kind of seafood, enterococci may be a more appropriate indicator than E. coli of risks to consumers from vibrios.     

Titania solar cells: new photovoltaic technology

Titania solar cells are a new type of photovoltaic device invented by Professor Michael Grätzel at Ecole Polytechnique Federale de Lausanne (Switzerland). Titania solar cells convert sunlight directly into electricity through a process similar to photosynthesis. It has performance advantages over other solar cells, which include the ability to perform well in low light and shade, and to perform consistently well over a wide range of temperatures. Titania solar cells can be fabricated to be either transparent or opaque in appearance. The simple materials, construction technique and processing equipment make Titania modules attractive for affordable power generation. Applications of such a module include many consumer and professional products, including vertically mounted solar tiles used as integrated building materials and, in future, used as power generating windows.     

On the Heat-Flux Dependent Thermoelasticity for Micropolar Porous Media

In the present paper, in the context of the linear theory of heat-flux dependent thermoelasticity for micropolar porous media, we derive a uniqueness theorem with no positive definiteness assumption on the elastic constitutive coefficients. Moreover, we prove, under non homogeneous initial conditions, a reciprocal relation and a variational principle. These generalize previous results about inhomogeneous and anisotropic micropolar thermoelastic materials.     

Study of green Sicilian table olive fermentations through microbiological,chemical and sensory analyses

The production of five different green table olive cultivars was studied by a combined strategy consisting of chemical, microbiological and sensory analyses. Cultivable microflora of samples collected during processing was monitored by plate counts on seven synthetic culture media. In all samples Enterobacteriaceae, Pseudomonaceae, staphylococci, lactic acid bacteria and spore-forming bacteria were undetectable. Yeasts and moulds were countable from the day 42 (2 log CFU/ml) till the end of fermentation (6 log CFU/ml). The use of three different approaches for microorganism detection, including a culture-independent methodology, revealed the presence of barely three yeast species during the entire fermentation period: Candida parapsilosis, Pichia guilliermondii and Pichia kluyveri. Biochemical features of technological interest were evaluated for 94 strains in order to investigate their potential role in fermentation of green Sicilian table olives.