Effect of drying temperature on polyphenolic content and antioxidant activity of apricots

This study was carried out in order to check for the influence of drying parameters on the phenolic compounds and antioxidant activity on two apricot cultivars (Pelese and Cafona) using two sets of air drying temperatures: (1) air temperature at 55 °C; (2) air temperature at 75 °C. Whole fresh and dried fruits were assessed for: phenolics, ascorbic acid, antioxidant activity and redox potential (all parameters were calculated on a dry matter basis). Analysis of data shows that the decrease in chlorogenic and neochlorogenic acid in Cafona cultivar is higher at the lower drying temperature. Catechin showed the same behaviour of hydroxycinnamic acids in both cultivars, while the decrease in the other compounds was significantly more marked in the sample dried at 75 °C. The antioxidant activity increased significantly in Cafona fruits and this increase was confirmed by a diminution of the redox potential.     

Characterization of Jatropha curcas oils and their derived fatty acid ethyl esters obtained from two different plantations in Cuba

The scope of this work is to evaluate some properties of the oils and derived fatty acid ethyl esters (FAEE) from two different Jatropha Curcas species planted in Cuba. The properties that were determined include the acid value, peroxide value, p-anisidine value and fatty acid ethyl esters composition. In order to study the influence of the genus species and geographic conditions on the fuel properties, the oils from Jatropha Curcas planted in two regions of Cuba and their derived FAEE were analyzed and compared. The two plantations were in San José (SJ) and Guantanamo (Gt) representing respectively the western and eastern part of the island.The analyses indicated that the FAEE obtained from Guantanamo has a higher acid value and peroxide value compared with the FAEE from San José. The p-anisidine values did not show a clear trend and the results of gas chromatography-mass spectrometry indicated a similar FAEE composition. The results obtained by gas chromatography are in good agreements with previous reports.     

High temperature tribological characterisation of TiAlSiN coatings produced by cathodic arc evaporation

This study reports on the wear properties at medium-high temperatures of TiAlSiN films deposited by cathodic arc evaporation on hot work steel substrates. The chemical composition and microstructure of the coatings were characterised by glow discharge optical emission spectroscopy, scanning electron microscopy and X-ray diffraction. The mechanical properties, i.e. hardness and elastic modulus were evaluated by nanoindentation, and the adhesion of the coatings was tested by scratch tests. Coatings with stoichiometries of Ti_0.31Al_0.1Si_0.06N_0.53 and Ti_0.23Al_0.12Si_0.09N_0.55 exhibit microstructures consisting of solid solutions of (Ti,Al,Si)N, where Al and Si replace Ti atoms. These films show high hardness and good adhesion strength to the hot work steels. Conversely, coatings with a stoichiometry of Ti_0.09Al_0.34Si_0.02N_0.55 show a wurtzite-like microstructure, low hardness and poor adhesion strength.The wear rates of the coatings were investigated by ball-on-disc experiments at room temperature, 200 °C, 400 °C and 600 °C, using alumina balls as counter surfaces. At room temperature, the films show wear rates of the same order of magnitude of TiN and TiAlN coatings. On the other hand, the wear rates of solid solution (Ti,Al,Si)N coatings measured at 200, and 400 °C are one order of magnitude smaller than those measured at room temperature due to the formation of oxide-containing tribofilms on the wear tracks. At 600 °C the wear rates increase but still keep smaller than those measured at room temperature, although this effect can be influenced by the softening of the steel substrates by over-tempering. EDS analyses revealed that, between 200 °C and 400 °C, the oxidation of the coating occurs only at the contact zone between the film and the counterpart body due to the sliding process.     

Syngas production from polyethylene and biogas in porous media combustion

The production of syngas from biogas (surrogate of CH₄/CO₂: 55/45 v/v) and polyethylene in a porous media combustion reactor is experimentally studied. The employed setup is novel and has not been studied before. A semi-continuous feed of solid fuel and a constant filtration velocity of the gaseous reactants of 17 cm/s were considered. Temperature, velocity of propagation, and composition of the syngas produced in the combustion waves were registered in a tubular reactor packed with a ceramic foam porous medium and two solid fuel inlets. In the first part of the study, a baseline determined by the filtration combustion of a biogas/air mixture through the ceramic foam at the equivalence ratio ($\mathrm{?}$) range $0.7\le \mathrm{?}\le 1.6$, having transient (upstream and downstream) and stationary combustion wave propagation regimes, is established. In the second part of this work, portions of the ceramic foam in two different separated zones are extracted, leaving space for the semi-continuous supply of polyethylene. In this second part the biogas-air combustion was performed only for $\mathrm{?}=0.8$ and $\mathrm{?}=1.6$. Although the combustion temperature decreased by the presence of polyethylene, it was found that the syngas (both H₂ and CO) yield was larger than for the baseline. The highest degrees of conversion to hydrogen and carbon monoxide was reached under the presence of polyethylene, having 45% and 67% for $\mathrm{?}=0.8$, and 45% and 60% for $\mathrm{?}=1.6$, respectively. These results are very promising and they demonstrate the capabilities of the presented methodology and experimental setup, which should encourage future attempts of applications of the technology.     

Improved thermal stability of oxide-supported naked gold nanoparticles by ligand-assisted pinning

We report a method to improve the thermal stability, up to 900 °C, of bare-metal (naked) gold nanoparticles supported on top of SiO(2) and SrTiO(3) substrates via ligand-assisted pinning. This approach leads to monodisperse naked gold nanoparticles without significant sintering after thermal annealing in air at 900 °C. The ligand-assisted pinning mechanism is described.     

A multiscale parallel computing architecture for automated segmentation of the brain connectome

Several groups in neurobiology have embarked into deciphering the brain circuitry using large-scale imaging of a mouse brain and manual tracing of the connections between neurons. Creating a graph of the brain circuitry, also called a connectome, could have a huge impact on the understanding of neurodegenerative diseases such as Alzheimer's disease. Although considerably smaller than a human brain, a mouse brain already exhibits one billion connections and manually tracing the connectome of a mouse brain can only be achieved partially. This paper proposes to scale up the tracing by using automated image segmentation and a parallel computing approach designed for domain experts. We explain the design decisions behind our parallel approach and we present our results for the segmentation of the vasculature and the cell nuclei, which have been obtained without any manual intervention.