Compaction pressure influence on material properties and sorption behaviour of LiBH4–MgH2 composite

Among different Reactive Hydride Composites (RHCs), the combination of LiBH₄ and MgH₂ is a promising one for hydrogen storage, providing a high reversible storage capacity. During desorption of both LiBH₄ and MgH₂, the formation of MgB₂ lowers the overall reaction enthalpy. In this work, the material was compacted to pellets for further improvement of the volumetric hydrogen capacity. The influence of compaction pressure on the apparent density, thermal conductivity and sorption behaviour for the Li-based RHC during cycling was investigated for the first time. Although LiBH₄ melts during cycling, decrepitation or disaggregation of the pellets is not observed for any of the investigated compaction pressures. However, a strong influence of the compaction pressure on the apparent hydrogen storage capacity is detected. The influence on the reaction kinetics is rather low. To provide explanations for the observed correlations, SEM analysis before and after each sorption step was performed for different compaction pressures. Thus, the low hydrogen sorption in the first cycles and the continuously improving sorption for low pressure compacted pellets with cycling may be explained by some surface observations, along with the form stability of the pellets.     

Synthesis and electrochemical polymerisation of 3′-functionalised terthiophenes: Electrochemical and spectroelectrochemical characterisation

A new terthienyl derivative, 4′-[(2,2′:5′,2″-terthien-3′-yl)methoxy]-2,2′:6′,2″-terpyridine, was synthesised in order to electrogenerate a new conducting polymer as an electrode coating suitable to complex metal ions. The characteristics of the system obtained have been defined through electrochemical and spectroelectrochemical techniques. The physical and chemical properties of 4′-[(2,2′:5′,2″-terthien-3′-yl)methoxy]-2,2′:6′,2″-terpyridine are compared with those of 3′-hydroxymethyl-2,2′:5′,2″-terthiophene, i.e. the corresponding trimer not bearing the terpyridine ligand. Under the same conditions for both monomers, both electrochemical and spectroelectrochemical tests show that 4′-[(2,2′:5′,2″-terthien-3′-yl)methoxy]-2,2′:6′,2″-terpyridine leads to the formation of a narrower molecular weight distribution, with shorter-conjugated polymer chains.     

Studies on the catalytic dechlorination and abatement of chlorided VOC: the cases of 2-chloropropane, 1,2-dichloropropane and trichloroethylene

The conversion of monochloropropanes and dichloropropanes over acid catalysts has been investigated in the presence of oxygen. In the temperature range of 450–550 K, dehydrochlorination of monochloropropanes to propene and HCl occurs selectively over silica–alumina, while significant formation of chlorinated by-products is observed over ZSM5 zeolite catalyst even at higher temperatures. Dichloropropanes conversion over silica–alumina catalyst gives rise mainly to chloropropenes in the temperature range 500–700 K. CO_x are predominant products only at the highest reaction temperatures (just above 700 K). Water vapor in the feed only slightly affects conversions and selectivities. Deactivation processes occur upon dichloropropane conversion, mainly due to coke deposition.

The conversion of highly chlorinated compounds, such as trichloroethylene (TCE) has been tested over silica–alumina and over HY zeolite in the presence of water vapor in the so-called “steam reforming” conditions (HVOC:water=1:2). With diluted feed (1200 ppm) on HY, reaction occurs above 800 K and formation of chlorinated by-products is minimized, CO_x being the main reaction products. At higher HVOC concentrations conversion is obtained at even lower temperature (600 K), but no more negligible by-products formation has been detected. In our conditions zeolite catalyst is more effective in TCE total conversion than silica–alumina.     

Blue pleiades,a new solution for device discovery and scatternet formation in multi-hop Bluetooth networks

In this paper we introduce a novel and unified approach to the problems of device discovery and scatternet formation for the Bluetooth standard. We introduce a stochastic model for Bluetooth device discovery and prove that a protocol based on very simple local rules generates a topology that, with high probability, is connected and, crucially, has constant maximum degree. Based on this, we develop a new protocol for device discovery and scatternet formation for multi-hop BlueTooth networks. By means of extensive ns2 simulations we show that our solution is simple to implement, fast and requires low overhead, both for the device discovery and the scatternet formation phases, and leads to better performance when compared to the major approaches so far proposed in the literature.     

Flow and Thermal Analysis during Hot Extrusion of Two Kinds of Stainless Steel: AISI 316Ti and AISI 329A

A mathematical model was developed to describe the mechanical and thermal behaviour of stainless steels during hot extrusion. The reference point for the study was the experimental data of the extrusion process performed on two stainless steels in order to take into account the most significant features of the process: temperature, velocities, extrusion ratio and the shape of the extrusion die. The developed simulation approach is based on the Navier‐Stokes equations which were used to compute the speed field in the steel during its passage in the die; this formalism allows to reach the resolution of the structural problem from the data easily measured during the industrial practice, i.e. press velocity and velocity of the extruded material at the exit from the die. The behaviour of the steel can be calculated through its constitutive law at high temperature from the fields of velocity, strain rate, strain and stress. The structural model is coupled with a thermal one based on the Fourier equation which provides the thermal field that plays a fundamental role in the microstructural features of the final product. The validation of the computational approach has been realized by an analysis of the obtained velocity distribution in the material and by a comparison between the calculated temperature field, the metallographic structure and the measured micro‐hardness values.     

A Rapid Method for the Recovery,Quantification and Electrophoretic Analysis of Proteins from Beer

A previously‐developed method for protein recovery from wine has been applied to beer and beer foam samples. The method involves the complexation of proteins with dodecyl sulfate (added as sodium salts) and subsequently the insolubilization of the protein‐detergent complexes by addition of potassium ions (added as KCl). The protocol allows preparation of proteins from a few hundred microliters of beverage in a few minutes. The precipitated proteins are free from interfering materials and are directly utilizable for quantitative and electrophoretic assays.     

Dam-Break Flows: Acquisition of Experimental Data through an Imaging Technique and 2D Numerical Modeling

This paper presents experimental and two-dimensional (2D) numerical results of four tests concerning rapidly varying flows induced by the sudden removal of a sluice gate. For the acquisition of the experimental data, an imaging technique capable of providing spatially distributed information was adopted: a coloring agent was added to the water, the opalescent bottom of the facility was backlighted, and photographs of the area of interest were taken. The gray tones of the acquired images were converted into water depths by means of transfer functions derived from a static calibration. The potential sources of error of the proposed procedure are discussed. A local comparison with an ultrasonic device showed a 20% maximum deviation in 95% of the observations. The tests were simulated through a 2D MUSCL-Hancock finite volume numerical model, based on the classical shallow water approximations, in which the intercell water depths are estimated according to the surface gradient method. A global analysis of the relative frequency distributions of the deviation between numerical and experimental results is performed. Despite some evident differences at a local scale, the adopted 2D numerical model is capable of reproducing the main features of the flow fields under investigation.     

An experimental investigation into the buckling and post-buckling of CFRP shells under combined axial and torsion loading

The results of an experimental study of the buckling and post-buckling behaviour of four unstiffened thin-walled CFRP cylindrical shells are presented. The test equipment allows axial and torsion loading, applied separately and in combination, using a position control mode, and includes a laser scanning system for the measurement in situ of the geometric imperfection as well as of the progressive change in deformations. The results identify the effect of laminate orientation, show that the buckling loads are essentially independent of load sequence and demonstrate that the shells are able to sustain load in the post-buckling field without any damage. The measured data are fundamental for the development and validation of analytical and numerical models and contribute to the definition of applicable strength design criteria of composite cylindrical shells in the post-buckling field, with the final aim of a larger structure weight saving.     

Bad but Bold: Ambivalent Attitudes Toward Men Predict Gender Inequality in 16 Nations.

A 16-nation study involving 8,360 participants revealed that hostile and benevolent attitudes toward men, assessed by the Ambivalence Toward Men Inventory (P. Click & S.T. Fiske, 1999), were (a) reliably measured across cultures, (b) positively correlated (for men and women, within samples and across nations) with each other and with hostile and benevolent sexism toward women (Ambivalent Sexism Inventory, P. Click & S.T. Fiske, 1996), and (c) negatively correlated with gender equality in cross-national comparisons. Stereotype measures indicated that men were viewed as having less positively valenced but more powerful traits than women. The authors argue that hostile as well as benevolent attitudes toward men reflect and support gender inequality by characterizing men as being designed for dominance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)