Nucleation and Crystallization of a Lithium Aluminosilicate Glass

An aluminosilicate glass of composition 61SiO₂6Al₂O₃10MgO6ZnO·12Li₂O·5TiO₂ (mol%) has been prepared by a melting process and investigated as far as crystallization is concerned. Glass-ceramic is easily obtained because glass shows a high tendency to crystallize starting from 700°C. The crystalline phases evolve with temperature, showing the aluminosilicates to be the main phase up to 1050°C, followed by metasilicates and silicates, some of which have lower melting points. The titanates of Mg and Zn develop from the phase-separated glass, soon after T _g, and grow to form nucleation centers for the other crystalline phases. The evolution from phase-separated glass to glass-ceramic has been followed by many thermal, diffractometric, spectroscopic, and microscopic techniques.     

Landslide Hazard Evaluation: The Landslide Hazard Curves

This paper presents an innovative, practical methodology to establish priorities for slope monitoring and the planning of stabilization works in large hilly areas. The study is based on the analysis of geological and geomorphological maps, identification of catchment areas, and the division of catchment areas into primary (with main stream) and secondary (without main stream) sub-basins. Attention was focused on secondary sub-basins and their characteristics: lithology; an ad hoc parameter q (related to the average rainfall, the size of the basin, and the width of the toe section), and the average slope inclination i. The technique presented enables the “landslide hazard curve,” unique for a given formation in homogenous areas with similar rainfall conditions and seismicity, to be drawn in a chart which features q and i. All the ascertained and assumed unstable areas represented in the chart are located above the landslide hazard curve.?The study was carried out scientifically by taking into account engineering aspects (geological, geomorphological, hydrological, and geotechnical), which influence slope stability. Groundwater levels, important in mapping out landslide prone areas, were considered in the study by means of the parameter q.     

SVD-Based Techniques for Zero-Padded Block Transmission Over Fading Channels

In this paper, the performance of filter bank transceivers in the presence of a dispersive time-variant channel is investigated. It is well known that filter bank transceivers can be adapted to the channel transfer function to yield intersymbol interference (ISI) cancellation. When the channel is time variant, several problems arise, since the transceiver should be changed whenever the channel evolves. In this paper, we will allow both the transmitter and the receiver to change and satisfy the interference-free condition, under the assumption of a zero-padded block transmission. In this case, the optimum transmitter-receiver pair can be computed by using a singular value decomposition (SVD) of the channel matrix. A fast receiver adaptation based on SVD tracking is presented. Simulation results show that minimum performance loss with respect to the optimum receiver can be achieved for our reduced complexity receiver     

Electrodeposition of nanostructured bioactive hydroxyapatite-heparin composite coatings on titanium for dental implant applications

In this paper we describe the one-pot fabrication of hydroxyapatite (HA)-heparin composites by electrodeposition onto Ti substrates and their characterisation in terms of structure, morphology, heparin content and bioactivity. HA coatings are well known and widely applied osteointegration enhancers, but post-implant healing rate in dental applications is still suboptimal: e.g. coagulation control plays a key role and the incorporation of an anticoagulant is considered a highly desirable option. In this study, we have developed an improved, simple and robust growth procedure for single-phase, pure HA-heparin films of thickness 1/3 μm. HA-heparin, forming nanowires, has the ideal morphology for bone mineralisation. Staining assays revealed homogeneous incorporation of sizable amounts of heparin in the composite films. The bioactivities of the HA and HA-heparin coatings on Ti were compared by HeLa cell proliferation/viability tests and found to be enhanced by the presence of the anticoagulant.     

Soluble or bound laminin elicit in human neuroblastoma cells short- or long-term potentiation of a K+ inwardly rectifying current: relevance to neuritogenesis

Changes in the resting potential (VREST) and in the underlying ionic conductances were measured by the patch-clamp technique in SH-SY5Y human neuroblastoma cells exposed to substrate-bound or soluble Laminin (bLN; sLN), as compared to integrin-independent substrates (polylysine (PL); bovine serum albumin (BSA)). While PL and BSA were ineffective, both forms of LN caused an early (5-15 min) activation of a peculiar type of Inwardly Rectifying K+ current (IIR) characterised by a voltage-dependent inactivation in the range of membrane potentials around -50/0 mV. IIR was blocked by Cs+ ions and by the antiarrhythmic drug E-4031, a specific inhibitor of the HERG-codified channels. In cells adherent to bLN, IIR potentiation (85%) persisted for 90-120 min and was accompanied by a similar, but transient, increase in the leakage conductance (GL). Successively, the persistence of a high IIR conductance and the decrease of GL progressively bring VREST from -12 to approximately -30 mV in about 120 min. On the other hand, in cells adherent to PL, exposure to sLN produced a similar but not persistent activation of IIR, without any increase in GL: this caused a rapid, transient hyperpolarisation of VREST. The effects of bLN and sLN were mimicked by antibodies raised against the integrin beta 1 subunit, suggesting a specific integrin-mediated mechanism. In fact, when bound to the culture dishes, these antibodies simultaneously activated the IIR and GL, whereas in soluble form they only activated IIR. Cells adherent to bLN emitted neurites, a process impaired by the block of IIR by E-4031 and Cs+. On the whole data suggest that the integrin-mediated activation of IIR plays a crucial role in the commitment to neuritogenesis of neuroblastoma cells, independently on the effects of this activation on VREST.     

A new philosophy for stochastic equivalent linearization

An extension, to the time-dependent situation, of what is known in static structural reliability as the ‘normal tail approximation’ is presented. This is pursued within the classical stochastic equivalent linearization scheme. Duffing and hysteretic oscillators are studied in detail.     

Load combination by partial safety factors

The Load and Resistance Factor Design (LRFD) format, which is a generic form of most current mechanical and structural design criteria, is accepted to be appropriate for load combination purposes. The meaning of the load factors in the framework of a LRFD format is discussed from a theoretical point of view. These load factors can be obtained by suitable calibration procedures. The problems that arise in the application of these procedures are analysed.A new calibration methodology is formulated and its operative aspects are dicussed. In this approach, the structure is designed to have a high reliability under permanent and quasi-permanent loads. Consistent degrees of safety for different design situations are achieved by calibrating the combination factors to be applied to the short-duration loads. Some numerical examples of this new calibration procedure are presented.The applications in reactor technology may be of some interest. The structural components of a nuclear power plant are generally subjected to several actions of different nature. By adopting the approach discussed in this paper, the reliability of every sub-structure has to be assessed only when the sub-structure is subjected to a set of few actions in combination. Moreover the safety analyses can be conducted in a deterministic context, all probabilistic calculations being limited to a preliminary investigation on the loads.     

Fast and air stable near-infrared organic detector based on squaraine dyes

In search for an organic material suitable for the detection of near-infrared electromagnetic radiation and at the same time capable of air stable operation of related devices, so to address the many applications envisaged with this technology (remote control, chemical/biological sensing, optical communication, spectroscopic and medical instruments), we explore the performance of a blend of hydrazone end-capped symmetric squaraines and phenyl C₆₁ butyric acid methyl ester. We succeed in developing air stable solution-processed devices with external quantum efficiency in the NIR as high as 3.5% and response times of few hundreds of nanoseconds. Essential to these achievements has been a detailed characterization of the devices performed by correlating the optoelectronic performances to the morphology of the layers (extracted from AFM measurements) and to the charge carrier mobility (extracted from transistor structures), enabling their optimization at the chemical level, by tailoring the squaraine substitution pattern, and at the device level, by tuning the blend composition. We show that a good balance between holes and electrons mobility is essential for high EQE and fast response speed, and that a smooth morphology is mandatory to achieve long term air stability and operability with no need for encapsulation.     

Effect of sonolysis on waste activated sludge solubilisation and anaerobic biodegradability

Activated sludge processes are key technologies in wastewater treatment. These biological processes produce huge amounts of waste activated sludge (WAS) or otherwise biosolids. Mechanical, thermal, and/or chemical WAS conditioning techniques have been proposed to reduce the sludge burden. Among the WAS treatments, the pre-treatment with ultrasound (US) is one of the most innovative processes. In many anaerobic digestion processes for the treatment of the sludge produced in wastewater treatment plants, the hydrolysis of the organic matter has been identified as the rate limiting step.This study is focused on the effect of US pre-treatment of WAS to the anaerobic digestion. Particle size reduction, Chemical Oxygen Demand (COD) solubilization and biodegradability by anaerobic digestion were monitored in order to find the optimal dose in US pre-treatment.The results show the better sonolysis conditions (US density, sonication time, specific energy) which can significantly improve the COD solubilisation and the anaerobic biodegradability.     

The circular economy of agro and post-consumer residues as raw materials for sustainable ceramics

The circular economy in the area of waste management implies their re-use as a raw material in different production cycles. Both the qualitative and quantitative characteristics of the residues from the agro sector and those of the products of the ceramics sector make possible to think of a feasible application. This review will illustrate some examples of recycling of residues deriving from animal and vegetable sectors (and two post consume products, spent coffee grounds, and packaging glass cullet), studied by the authors, falling within the concept of urban and agricultural sustainable development. Not only the most traditional products such as glass-ceramics, glazes, bricks, but also the most innovative lightweight aggregates for plant structures or in and out soil cultivation, as well as additives such as deflocculants for ceramic suspensions, which will be illustrated from the design/production, characterization, and comparison with commercial products.