Organic acid profile of chestnut (Castanea sativa Mill.) as affected by hot air convective drying

The objective of the present work was to evaluate the effect of hot air convective drying on the organic acid profile of chestnut. An extractive method, with internal standard, followed by HPLC-UV was validated, allowing the quantification of malic, ascorbic, citric, and fumaric acids with good precision and accuracy. Fresh chestnuts presented differences between varieties. The thermal process caused equivalent losses of ascorbic acid on both varieties, but higher losses of malic acid in Longal. Furthermore, fumaric acid contents increased on both varieties. Therefore, hot air convective drying affected the organic acid composition of chestnut slices, and this effect was varietal dependent.     

Neutron bombardment of C60 and C70 fullerenes: A spectroscopic and calorimetric study

C₆₀ and C₇₀ fullerenes were neutron-bombarded to an integral dose of 3.28×10¹⁶ n cm^?2. After the neutron treatment the trichloromethane soluble fraction was determined spectrophotometrically and C₆₀ insoluble fraction was found at 3.8% while the insoluble fraction of C₇₀ 17.9%. The formation of the CHCl₃ insoluble fraction is due to polymerization and incipient amorphization of the neutron-bombarded fullerenes where C₇₀ appears more sensitive to radiation damage than C₆₀. Raman spectroscopy was used for the characterization of the irradiated fullerenes as well as electron spin resonance (ESR) and electronic absorption spectroscopy on solid samples. Differential scanning calorimetry (DSC) to 630°C was employed for the determination of the Wigner energy of the neutron-damaged fullerenes. The results are consistent with a higher level of radiation damage reached by C₇₀ in comparison to C₆₀ at the same neutron dose.     

Modeling the mechanical properties of optimally processed cordierite–mullite–alumina ceramic foams by X-ray computed tomography and finite element analysis

Bulk and cellular cordierite ceramics were prepared from a non-stoichiometric powder consisting of corundum, talc (triclinic), α-quartz, K-feldspar, kaolinite, mullite and a small amount of a glass phase. The optimal sintering processing route was evaluated to obtain good mechanical properties. A high flexural strength of 120 MPa and a Young’s modulus of 99 GPa were achieved. The ceramic foams were fabricated by impregnation of polymer preforms with the optimized stock suspension. The mechanical properties of ceramic foams were studied by impulse excitation and compression tests. The Gibson–Ashby model predicted the ceramic foam’s effective modulus and its elastic limit strength well, as measured experimentally. In addition, the actual three-dimensional (3-D) structure obtained from X-ray computed tomography (CT) coupled with the finite element method (FEM) was used to calculate the Young’s modulus and the elasticity limit of the ceramic foam; however, this did not produce aby better agreement between the calculated values and the experimental results. The discrepancy between the Gibson–Ashby model and FEM could probably be attributed to the accuracy and small volume of representative reconstructed 3-D cellular structure. Taking account of the effect of the internal hollow structure on the stress localization in the ceramic struts, the CT–FE modeling provides a good measure of the adaptability and predictability of actual ceramic foam structures for realistic damage modeling.     

Context-based wireless mesh networks: a case for network virtualization

Wireless Mesh Networks (WMNs) have gained increasing attention as an attractive means to provide connectivity in complement to access as offered by regular Internet Service Providers (ISPs). Such a grass-root technique, however, often suffers from detrimental operating conditions and poor quality. Network virtualization, on the other hand, has been widely advocated as a possibility to overcome what has often been referred to as the ossification of the Internet. Combining the concept of network virtualization with WMN technology, therefore, appears to be promising and desirable. It is envisioned that well managed multiple Virtual Networks (VNs) may overcome shortcomings of WMNs on the one hand, and extend the reach of the Internet beyond its current confinement into the realm and control of the user on the other hand. In this paper, we argue for a context-based approach for an effective means to extend multi-VNs from the Internet domain into WMN environments. We describe both mobility and preferences as context models in order to create virtualized WMNs based on these types of context models. As a result, it is envisioned to achieve a comprehensive connectivity coverage, accompanied by high assurance in network quality. We further present a distributed solution to manage multi-VNs, and a mobility-aware context use case to demonstrate the usefulness of our approach.     

Affective speech interface in serious games for supporting therapy of mental disorders

We describe a novel design, implementation and evaluation of a speech interface, as part of a platform for the development of serious games. The speech interface consists of the speech recognition component and the emotion recognition from speech component. The speech interface relies on a platform designed and implemented to support the development of serious games, which supports cognitive-based treatment of patients with mental disorders. The implementation of the speech interface is based on the Olympus/RavenClaw framework. This framework has been extended for the needs of the specific serious games and the respective application domain, by integrating new components, such as emotion recognition from speech. The evaluation of the speech interface utilized purposely collected domain-specific dataset. The speech recognition experiments show that emotional speech moderately affects the performance of the speech interface. Furthermore, the emotion detectors demonstrated satisfying performance for the emotion states of interest, Anger and Boredom, and contributed towards successful modelling of the patient’s emotion status. The performance achieved for speech recognition and for the detection of the emotional states of interest was satisfactory. Recent evaluation of the serious games showed that the patients started to show new coping styles with negative emotions in normal stress life situations.     

Prediction of the air wave due to blasting inside tunnels: Approximation to a ‘phonometric curve’

A review of the results of a previous research, has pointed out that only the magnitude of the blasting air wave at the tunnel portal depends on the tunnel and blasting design parameters (section, length, distance to the portal, maximum charge per delay…). For a given sound level at the tunnel portal, the magnitude of the air wave outside the tunnel depends on the attenuation due to natural or artificial barriers, similar to how a lamp focuses the light more along a given direction than along others. In this work, the air wave propagation outside the tunnel is briefly explained and a phonometric and iso-attenuation curves are proposed in order to represent the phenomenon and to synthesize the solution for a given case. Finally, a charge–distance curve is proposed in order to solve the problem in an easy way.     

Surface Dependence of Protein Nanocrystal Formation

The self‐assembly kinetics and nanocrystal formation of the bacterial surface‐layer‐protein SbpA are studied with a combination of quartz crystal microbalance with dissipation monitoring (QCM‐D) and atomic force microscopy (AFM). Silane coupling agents, aminopropyltriethoxysilane (APTS) and octadecyltrichlorosilane (OTS), are used to vary the protein–surface interaction in order to induce new recrystallization pathways. The results show that the final S‐layer crystal lattice parameters (a = b = 14 nm, γ = 90°), the layer thickness (15 nm), and the adsorbed mass density (1700 ng cm^?2) are independent of the surface chemistry. Nevertheless, the adsorption rate is five times faster on APTS and OTS than on SiO_2, strongly affecting protein nucleation and growth. As a consequence, protein crystalline domains of 0.02 µm² for APTS and 0.05 µm² for OTS are formed, while for silicon dioxide the protein domains have a typical size of about 32 µm². In addition, more‐rigid crystalline protein layers are formed on hydrophobic substrates. In situ AFM experiments reveal three different kinetic steps: adsorption, self‐assembly, and crystalline‐domain reorganization. These steps are corroborated by frequency–dissipation curves. Finally, it is shown that protein adsorption is a diffusion‐driven process. Experiments at different protein concentrations demonstrate that protein adsorption saturates at 0.05 mg mL^?1 on silane‐coated substrates and at 0.07 mg mL^?1 on hydrophilic silicon dioxide.