Cone calorimeter testing of S2 glass reinforced polymer composites

With the ever increasing demand for fuel savings on vehicles, there is a strong push to replace metal with polymeric + fiber (carbon/glass) composites. However, the replacement of metal with polymeric composites can lead to additional fire risk. Our study focused on glass fiber reinforced polymer composites meant for vehicular structural applications, and flammability performance of these composites was studied by cone calorimetery. The effects of fiberglass loading, nanocomposite use (clay, carbon nanofiber) and polymer type (epoxy, phenolic) were studied under a heat flux of 50kW/m² to better understand the potential effects that these variables would have on material flammability. It was found that as fiberglass loading increased, flammability decreased, but at a cost to structural integrity of the residual polymer + fiber char. The use of nanocomposites has little effect on reducing flammability in this set of samples, but the use of phenolic resins in comparison with epoxy resins was found to yield the greatest improvements in flammability performance. Further, the phenolic system yielded a higher level of structural integrity to the final polymer + fiberglass char when compared with the other polymer systems of low heat release. Copyright © 2009 John Wiley & Sons, Ltd.     

Novel biodegradable, biomimetic and functionalised polymer scaffolds to prevent expansion of post-infarct left ventricular remodelling

Over the past decade, a large number of strategies and technologies have been developed to reduce heart failure progression. Among these, cardiac tissue engineering is one of the most promising. Aim of this study is to develop a 3D scaffold to treat cardiac failure. A new three-block copolymer, obtained from δ-valerolactone and polyoxyethylene, was synthesised under high vacuum without catalyst. Copolymer/gelatine blends were microfabricated to obtain a ECM-like geometry. Structures were studied under morphological, mechanical, degradation and biological aspects. To prevent left ventricular remodelling, constructs were biofunctionalises with molecularly imprinted nanoparticles towards the matrix metalloproteinase MMP-9. Results showed that materials are able to reproduce the ECM structure with high resolution, mechanical properties were in the order of MPa similar to those of the native myocardium and cell viability was verified. Nanoparticles showed the capability to rebind MMP-9 (specific rebinding 18.67) and to be permanently immobilised on the scaffold surface.     

Delta conversion parameter between pH scales (SWpH and SSpH) in acetonitrile/water mixtures at various compositions and temperatures

The SSpH in acetonitrile/water mixtures at different temperatures cannot be directly measured because of the lack of calibration buffers in these hydroorganic media at most temperatures different from 25 degrees C. In this paper, the delta parameter has been determined for acetonitrile/water mixtures from 0 up to 90% acetonitrile at different temperatures from 15 to 60 degrees C, and the values were fitted to a very simple simultaneous function of composition and temperature. The delta values allow conversion of the SWpH scale (pH measured in acetonitrile/water with electrodes calibrated in water) to the SSpH scale (pH measured in acetonitrile/water with electrodes calibrated in the same acetonitrile/water mixture). The practical determination of SWpH is direct because the calibration of the electrodes is carried out with commercial aqueous standard buffers. Thus, the SSpH value of any buffered acetonitrile/water mobile phase used in reversed-phase liquid chromatography, which is directly related to the ionized fraction of analyte and, therefore, to its average retention, can be easily known at any temperature from the measured SWpH and the corresponding delta value.     

Laser-assisted fabrication of biomolecular sensing microarrays

With the aim of obtaining high density biosensing arrays we use pulsed laser deposition to immobilize functional biomolecules on useful surfaces, and micro- and nanopatterning techniques for fabrication of prototype immunosensing bioarrays. We report biological activity tests demonstrating the functional properties of the immobilized proteins and atomic force microscopy characterization of films of nanometric dimensions. Laser-fabricated immunofluorescent arrays are analyzed to check that the intensity and contrast of the sensing sites allow efficient device fabrication. We have also developed an elementary array of heterogeneous reaction sites and tested its performance by simultaneous incubation with the different specific antigens.     

Recent improvements to the ITER neutral beam system design

The ITER [1] fusion device is expected to demonstrate the feasibility of magnetically confined deuterium–tritium plasma as an energy source which might one day lead to practical power plants. Injection of energetic beams of neutral atoms (up to 1 MeV D⁰ or up to 870 keV H⁰) will be one of the primary methods used for heating the plasma, and for driving toroidal electrical current within it, the latter being essential in producing the required magnetic confinement field configuration. The design calls for each beamline to inject up to 16.5 MW of power through the duct into the tokamak, with an initial complement of two beamlines injecting parallel to the direction of the current arising from the tokamak transformer effect, and with the possibility of eventually adding a third beamline, also in the co-current direction. The general design of the beamlines has taken shape over the past 17 years [2], and is now predicated upon an RF-driven negative ion source based upon the line of sources developed by the Institute for Plasma Physics (IPP) at Garching during recent decades [3], [4], [5], and a multiple-aperture multiple-grid electrostatic accelerator derived from negative ion accelerators developed by the Japan Atomic Energy Agency (JAEA) across a similar span of time [6], [7], [8]. During the past years, the basic concept of the beam system has been further refined and developed, and assessment of suitable fabrication techniques has begun. While many design details which will be important to the installation and implementation of the ITER beams have been worked out during this time, this paper focuses upon those changes to the overall design concept which might be of general interest within the technical community.     

A model to manage a large number of transactions: a case study

The aim of this paper is to present a model for the Computer Centre of an important Italian banking group. The model groups data and transactions to deal with the large dimension of the Centre. The transactions arrivals are considered as Posson stochastic variables and the probability values are estimated. Some computational results are given.     

Assessing soil respiration by means of near-infrared diode laser spectroscopy

High-resolution diode laser spectroscopy in the near-infrared region is applied to the accurate measurement of soil respiration. In particular, the use of a diode-laser-based spectrometer has allowed the implementation, for the first time, of a static accumulation method capable of measuring soil respiration from continuous measurements of CO(2) concentrations, with minor perturbation on soil respiration as well as on CO(2) transport and emission. The system has been tested in a laboratory experiment by detection of CO(2) production from sandy matrices, inoculated with active soil microbes and supplied with different amounts of decomposable plant material. Respiration rates of all samples were then retrieved using a diffusion model. The results of the laboratory tests are in agreement with those expected on the basis of sample composition. Examples of operation with real soil samples are also reported. We discuss the possible field application of the system, in conjunction with closed static soil chambers.     

A Reconfigurable High-Speed Optical System for Integrated Local Communications

The introduction of optical fibers in local area networks makes it possible to implement wide-band communication systems integrating all the communication services (telephone, data, images, etc.) foreseen in future office scenarios. This paper describes a reconfigurable high-speed local communication system, which is currently under development at the Centro Studi e Laboratori Telecomunicazioni (CSELT), conceived to attain high reliability and efficiency features, therefore suitable for a wide range of application environments, such as automated offices, integrated manufacturing, hospitals, etc. The access organization is based on a hybrid (i.e., circuit and packet) protocol, which guarantees each type of traffic the required grade of service, while allowing an optimal exploitation of the transmission capacity. Fault-tolerance issues are taken as a guideline in the overall system conception and, in particular, in the transmission subsystem design. The transmission subsystem presently uses available optical technology to implement a loop-shaped bus topology capable of reconfiguring by means of a distributed algorithms, when a link or node fails.     

Steady-state mathematical models of battery storage plants withline-commutated converters

Battery storage plants can be interfaced to electric power systems by AC/DC line-commutated converters, whose behavior is strongly influenced by AC and DC side interactions, and which can work in nonideal conditions such as those arising from voltage harmonics and imbalances. Mathematical models of battery storage plants with conventionally and nonconventionally controlled line-commutated converters are presented. The aim is to carry out a complete harmonic analysis in steady-state nonideal conditions. The models, which include the DC side of the converter, can be directly employed in an iterative harmonic analysis of a power system with converters. Numerical simulation results are discussed     

Evaluation of sustainability of a city through fuzzy logic

The sustainable indicators are characterized by a low degree of aggregation and a high amount of information. An indicator must show a synthetic representation of a real environmental, by using a value or a parameter, so that they can be easily used by policy makers. It is necessary to connect, therefore, the various systems in an appropriately integrated sustainable system. The indicators need to be aggregated based on the structure of the data. Each indicator must to be defined through a weight with reference to another weighted indicator.