Updating landslide inventory maps using Persistent Scatterer Interferometry (PSI)

This work illustrates the contribution of persistent scatterer interferometry (PSI) from radar satellites ERS (European Remote Sensing satellite) and ENVISAT (Environmental Satellite) for the updating of a pre-existing landslide inventory (LSI) map: the main purpose is to change or confirm the landslide state of activity and geometry and to identify new landslides. Radar data have been integrated with optical images and ancillary data in a 1320 km² wide river basin (Biferno Basin) located in the central-eastern part of Italy. The geological setting of the area is characterized by clay and alternated clayey, silt and sandy formations that are affected by slow landslides. Field validation confirmed the results and the capabilities of multi-interferometric synthetic aperture radar data, integrated and coupled with conventional techniques, to support landslide investigation at the regional scale thanks to the available archive of repeated satellite data, which provides measurements of ground displacements with a millimetre-scale accuracy. In the study area, about 9% of the pre-existing LSI has been modified by means of permanent scatterer (PS) information, 15% of which have changed the state of activity from dormant to active and 95 new landslides were detected. The radar interpretation method applied in Biferno Basin confirms its high capability of detecting and mapping landslides at basin the scale: the information acquired from radar interpretation is the basis of the proposed method to evaluate the state of activity and the intensity of slow landslides. However, it is clear that limitations exist and this method does not always support the updating of LSI for the whole study area. We consider this methodology and procedure as a portable and suitable one for different geological and geomorphological environments.     

Study of the kinetics of recrystallisation of dispersion-strengthened (Al/Al2O3) alloys

The kinetics of recrystallisation of an SAP alloy containing 5.25 wt % oxide has been studied, mainly by metallographic observations and transmission electron microscopy. At the beginning of the process the isothermal reaction follows the Avrami lawx=1– exp (–Bt ^k) withk – 1.7. A deviation from the above kinetics takes place with increasing time; it is shown by metallographic observations and from the effect of preliminary recovery that this behaviour results from competition between recovery and recrystallisation. The competing process has an activation energy close to the value of 1.57 eV, previously determined for the stage of dislocation recovery preceding recrystallisation.Results reported by other authors have been analysed, and it is noticed that competition is a general feature of recrystallisation in these alloys; this effect becomes more pronounced with increasing oxide concentration, and can ultimately stop recrystallisation. The analysis of the kinetics of recrystallisation indicates that the dispersed phase not only reduces the driving force for grain boundary migration, but also affects mobility by raising the activation energy of the process.     

Scheduling assembly tasks with caterpillar precedence constraints on dedicated machines

In this work, we address the problem of scheduling a set of n non-preemptive tasks on m dedicated machines in order to minimise the makespan. For each task deterministic processing times and a specific processing machine are given, moreover a set of precedence constraints among the tasks are known. We present a heuristic and some lower bounds on the minimum makespan for a relevant case in manufacturing applications, namely when the precedence constraints form a caterpillar graph. A caterpillar is a directed tree consisting of a single directed path and leaf nodes each of which is incident to the directed path by exactly one incoming arc. A number of computational experiments are also performed in order to test the performance of the proposed solution algorithm.     

Enzymatic Kinetic Resolution of 2-Piperidineethanol for the Enantioselective Targeted and Diversity Oriented Synthesis

2-Piperidineethanol (1) and its corresponding N-protected aldehyde (2) were used for the synthesis of several natural and synthetic compounds. The existence of a stereocenter at position 2 of the piperidine skeleton and the presence of an easily-functionalized group, such as the alcohol, set 1 as a valuable starting material for enantioselective synthesis. Herein, are presented both synthetic and enzymatic methods for the resolution of the racemic 1, as well as an overview of synthesized natural products starting from the enantiopure 1.     

An innovative membrane-electrode assembly for efficient and durable polymer electrolyte membrane fuel cell operations

An innovative membrane-electrode assembly, based on a polyoxometalate (POM)-modified low-Pt loading cathode and a sulphated titania (S-TiO₂)-doped Nafion membrane, is evaluated in a polymer electrolyte membrane fuel cell. The modification of fuel cell cathode with Cs₃HPMo₁₁VO₄₀ polyoxometalate is performed to enhance particles dispersion and increase active area, allowing low Pt loading while maintaining performance. The POM's high surface acidity favors kinetics of oxygen reduction reaction. The mesoporous features of POM allow the embedding of Pt inside the micro-mesopores, avoiding the Pt aggregation during fuel cell operation and delaying the aging process, with consequent increase of lifetime. On the other hands, commercial Nafion is modified with superacidic sulphated titanium oxide nanoparticles, allowing operation at low relative humidity and controlled polarization of the MEA. Further MEAs, formed by unmodified Nafion membrane and the POM-based cathode, as well as sulphated titanium-added Nafion and commercial Pt-based electrodes, are used as terms of comparison. The cell performances are studied by polarization curves, electrochemical impedance spectroscopy, Tafel plot analysis and high frequency resistance measurements. The dependence of cell performances on relative humidity is also studied. The catalytic and transport properties are improved using the coupled system, despite the reduced Pt loading, thanks to rich proton environment provided by cathode and membrane.     

Modes of Knowledge Accumulation, Entry Regimes and Patterns of Industrial Evolution

This paper explores the interplay between entry, selection andinnovative learning as determinants of industrial evolution.It proposes a model aimed at capturing some essential featuresof learning and competition as drivers of the dynamics. Usingboth analytical and numerical techniques, the paper disentanglespossible generic properties which robustly hold for a wide rangeof parameterizations. In particular, the paper identifies differentgeneric ‘evolutionary archetypes’, defined by characteristicinteractions between entry/exit regimes, learning and industrialstructures.     

Si-SiC-ZrB2 ceramics by silicon reactive infiltration

Silicon carbide ceramics obtained by silicon reactive infiltration are nowadays employed within industry in several high temperature applications. Although these ceramics show good thermo-mechanical properties and oxidation resistance, they suffer temperature limitations (1400 °C). At higher temperatures another type of ceramics, commonly known as ultra high temperature ceramics (UHTCs), is under study. These include the transition metal diborides of group IV; one in particular, zirconium diboride, is interesting in certain applications (e.g. aerospace) because of its low relative density. ZrB₂-SiC ceramics show good thermo-mechanical properties and maintain the “protective” passive oxidation regime of their scales over a wide range of temperatures.This paper presents a feasibility study on a manufacturing methodology to produce Si-SiC-ZrB₂ bulk ceramics taking advantage of the reactive infiltration technique. This technique allows lower processing temperatures and near to net shape capability due to low shrinking of the green compacted bodies. C-SiC-ZrB₂ preforms were successfully infiltrated with molten silicon. The resulting Si-SiC-ZrB₂ composites showed promising oxidation behavior, similarly to that reported in other works. Bulk material optimization was performed with a view to manufacturing Si-SiC-ZrB₂ ceramic matrix composites by silicon reactive infiltration in future.     

Emodin prevents intrahepatic fat accumulation, inflammation and redox status imbalance during diet-induced hepatosteatosis in rats

High-fat and/or high-carbohydrate diets may predispose to several metabolic disturbances including liver fatty infiltration (hepatosteatosis) or be associated with necro-inflammation and fibrosis (steatohepatitis). Several studies have emphasized the hepatoprotective effect of some natural agents. In this study, we investigated the potential therapeutic effects of the treatment with emodin, an anthraquinone derivative with anti-oxidant and anti-cancer abilities, in rats developing diet-induced hepatosteatosis and steatohepatitis. Sprague-Dawley rats were fed a standard diet (SD) for 15 weeks, or a high-fat/high-fructose diet (HFD/HF). After 5 weeks, emodin was added to the drinking water of some of the SD and HFD/HF rats. The experiment ended after an additional 10 weeks. Emodin-treated HFD/HF rats were protected from hepatosteatosis and metabolic derangements usually observed in HFD/HF animals. Furthermore, emodin exerted anti-inflammatory activity by inhibiting the HFD/HF-induced increase of tumor necrosis factor (TNF)-α. Emodin also affected the hepatocytes glutathione homeostasis and levels of the HFD/HF-induced increase of glutathionylated/phosphorylated phosphatase and tensin homolog (PTEN). In conclusion, we demonstrated that a natural agent such as emodin can prevent hepatosteatosis, preserving liver from pro-inflammatory and pro-oxidant damage caused by HFD/HF diet. These findings are promising, proposing emodin as a possible hindrance to progression of hepatosteatosis into steatohepatitis.