On the corrosion behaviour of laser-irradiated aluminium surfaces

The corrosion behaviour of laser-irradiated aluminium surfaces was studied by means of the characterization of anodic oxide layers.Thin oxide layers were prepared by anodizing in 3% ammonium tartrate solution under potentiostatic control. Layers grown on laser-irradiated surfaces showed improved resistance towards pitting attack compared with those grown on unirradiated surfaces.Oxide layers were prepared by anodizing in an acid solution under galvanostatic control. These layers were always thicker and morphologically more uniform, as well as being without microcracks after a sealing treatment in boiling water, when they were grown on irradiated surfaces.These results support the hypothesis that a chemically inert metal surface is formed as a result of laser treatment.     

An On-Line Pneumatic Cigarette Inspection Device Based on Two Tightly Coupled Microprocessors

Ventilation is a technique for controlling the amount of both nicotine and tar delivered to smokers. VECOM is a system designed to control cigarette ventilation. It operates on every cigarette, on-line with the production process, taking measurements in accordance with a pneumatic model of ventilated cigarettes. Presented are the problems associated with performing on-line measurements, error correction, and overall system organization.     

High temperature distillation process with sea water feed decalcification pretreatment

The performance ratio of a desalination plant can be increased to reach 16–18 by coupling it with a decalcification pretreatment by ion exchange of the sea-water make-up, so making MSF comparable with RO from energetic point of view. A new strong cationic resin DECAL has been tailored; its main features are high selectivity towards the calcium ion and low concentration of the regenerating brine. These characteristics make it compatible with the normal operating range of multiflash plants and very suitable for the above service, when compared with other resins.The optimum coupling conditions of the whole plant, as has been pointed out, lie between 140°C and 150 °C for the top brine temperature and 2 to 2.5 for the brine concentration factor. In these conditions it is possible to operate with sea water-resin bed ratio higher than 20.     

Chemical kinetics and diffusion in poly(butylene terephthalate) solid-state polycondensation: Experiments and theory

Postpolymerization was obtained in solid PBT sheets, by annealing in a dry nitrogen stream at 214°C. After different reaction times, the samples were cut into thin slices. The M_w profile within the sample was obtained through intrinsic viscosity measurements in a phenol–TCE mixture. At each location inside the sample, the [η] vs. time curve typically shows a maximum, which is rather broad at the midplane and much sharper at the external surface. The phenomenon was mathematically described by accounting for both diffusion and chemical reactions within the slab; five simultaneous chemical reactions have been considered. The observed behavior is found to be essentially due to two competing processes, i.e., the diffusion of the low molecular weight species generated during the polycondensation and the thermal degradation reaction. The model predictions are compared with the experimental data showing a satisfactory agreement.     

Book Embeddability of Series–Parallel Digraphs

In this paper we deal with the problem of computing upward two-page book embeddings of Two Terminal Series-Parallel (TTSP) digraphs, which are a subclass of series-parallel digraphs. An optimal O(n) time and space algorithm to compute an upward two-page book embedding of a TTSP-digraph with n vertices is presented. A previous algorithm of Alzohairi and Rival [1] runs in O(n³) time and assumes that the input series-parallel digraph does not have transitive edges. An application of this result to a computational geometry problem is also discussed. More precisely, upward two-page book embeddings are used to deal with the upward point-set embeddability problem, i.e., the problem of mapping planar digraphs onto a given set of points in the plane so that all edges are monotonically increasing in a common direction. The equivalence between upward two-page book embeddability and upward point-set embeddability with at most one bend per edge on any given set of points is proved. An O(n log n)-time algorithm for computing an upward point-set embedding with at most one bend per edge for TTSP-digraphs is presented.     

Terahertz LC Microcavities: From Quantum Cascade Lasers to Ultrastrong Light-Matter Coupling

We review research on the physics of intersubband transitions in the THz range in a sub wavelength microcavity environment. Laser action was achieved at 1.5 THz by inserting quantum cascade gain material between the capacitor plates of a new resonant LC cavity, achieving a normalized mode volume ratio of only $V_{eff}/(\lambda /2n)^{3}=0.12$ of the cavity mode $V_{eff}$ and the normalized optical volume $(\lambda /2n)^{3}$ . By using the same cavity as the constituting meta-atom of a THz metamaterial, strong and ultra strong light matter coupling was observed up to room temperature. Finally, the same metamaterial coupled to parabolic semiconductor quantum wells was investigated in the regime of electrical in-plane pumping, showing THz emission in the ultra strong coupling regime.     

Cycling losses in refrigeration equipment: An experimental evaluation

Cycling losses may be defined as those inefficiencies that reduce the performances of units during the transient period. They may be quantified by comparing the Energy Efficiency Ratio (EER) of a cycling unit and the EER of the same unit working continuously.The on-off control is the most widespread strategy for modulating; therefore, a reliable evaluation of cycling losses is fundamental to assess the EER of the system. The mentioned losses have been experimentally evaluated on a test rig, and logged data demonstrate a loss up to 13% with respect to steady operations when the load factor is lower than 10% and a Thermostatic Expansion Valve (TEV) is used. The insertion of a solenoid valve in series with the TEV can reduce the losses but the best results are obtained by using the Electronic Expansion Valve (EEV) instead of the TEV.     

Air-liquid biofilm formation is dependent on ammonium depletion in a Saccharomyces cerevisiae flor strain

Air–liquid biofilm formation appears to be an adaptive mechanism that promotes foraging of Saccharomyces cerevisiae flor strains in response to nutrient starvation. The FLO11 gene plays a central role in this phenotype as its expression allows yeast cells to rise to the liquid surface. Here, we investigated the role of ammonium depletion in air–liquid biofilm formation and FLO11 expression in a S. cerevisiae flor strain. The data obtained show that increasing ammonium concentrations from 0 to 450 m m reduce air–liquid biofilm in terms of biomass and velum formation and correlate with a reduction of FLO11 expression. Rapamycin inhibition of the TOR pathway and deletion of RAS2 gene significantly reduced biofilm formation and FLO11 expression. Taken together, these data suggest that ammonium depletion is a key factor in the induction of air–liquid biofilm formation and FLO11 expression in S. cerevisiae flor strains. Copyright © 2011 John Wiley & Sons, Ltd.     

The influences of geological and land use settings on shallow landslides triggered by an intense rainfall event in a coastal terraced environment

Several factors (including slope morphology, geological and structural settings, the mechanical properties of soils, weathering, hydrological and hydrogeological conditions and land use changes) can affect the origin and development of shallow landslides induced by rainfall. On 25 October 2011, an intense rainfall occurred in a wide area of Italy between eastern Liguria and northern Tuscany, triggering thousands of shallow landslides and causing widespread flooding. Floods and landslides caused severe damage to villages and infrastructure and caused 13 fatalities. This study was conducted to investigate the shallow landslides triggered by the rainfall in the Vernazza basin (Cinque Terre in eastern Liguria), where landslides and debris floods caused 3 fatalities and damage of approximately €130 million. The Vernazza basin, which is characterised by steep slopes, geological heterogeneity and unusual land use settings (approximately 50 % of the slopes have been terraced for centuries), was chosen as the focus of this study, conducted to assess the influences of several factors on landslide occurrence. Field surveys and engineering geological investigations, including laboratory and in situ tests, were carried out at various sites to assess the stratigraphic and geotechnical features of the soil slope covers. A basic engineering geological zoning was carried out, taking into account the bedrock lithology, the geotechnical properties of the soils and the land use settings. On the basis of a detailed inventory of the shallow landslides that occurred, the distribution of the landslides was analysed with respect to the slopes, the bedrock lithology, the land uses and the engineering geological setting. Terraced areas on impermeable bedrock were identified as the main landslide-prone areas. The results of the study also showed that the time since abandonment of terraces plays an important role in the occurrence of shallow landslides induced by rainfall.