Vincenzo Ferrara

An addressing effective computer model for surface stabilized ferroelectric liquid crystal cells

Abstract A simple uniform director model is discussed which provides, for the first time, an agreement with experimental data for the dynamic optical behaviour of SSFLC cells subject to matrix addressing waveforms. Its use in fast running, interactive software has enabled us to design new, high speed matrix addressing schemes which have been experimentally tested.

A review on ground penetrating radar technology for the detection of buried or trapped victims

The localization of people buried or trapped under snow or debris is an emerging field of application of ground penetrating radar (GPR). In the last years, technological solutions and processing approaches have been developed to improve detection accuracy, speed up localization, and reduce false alarms. As such, GPR can play an active role in cooperative approaches required to tackle such emergencies. In this work, we present and briefly analyze the evolution of research in this field of application of GPR technology. In doing so, we adopt a point of view that takes into account that avalanches and collapsed buildings are two scenarios that call for different GPR approaches, since the former can be tackled through image processing of radar data, while the latter rely on the detection of the Doppler frequency changes induced by physiological movements of survivors, such as breathing.

Use of Ptfe Alignment Layers in Passive Addressed Ssflc Displays

Abstract Polytetrafluoroethylene (PTFE or Teflon®) layers have been developed as orientation films in order to produce ferroelectric liquid crystals displays with improved addressing behaviour. PTFE layers have been friction deposited on glass substrate with ITO electrodes at various temperatures in the range 130 °C-200 °C. The PTFE layers have been used to assemble displays which were addressed and showed no hysteresis, reduced image sticking and reduced switching time with respect to standard test cells employing rubbed polymers as alignment layers. In order to assure the best electro-optical performance, PTFE films have been characterized from the point of view of uniformity and thickness as function of deposition parameters.

Influence of Charge Transfer Complex Doping of Polyamide Alignment Film on SSFLC Cell Performance

Abstract New alignment films for surface stabilized ferroelectric liquid crystals displays (SSFLCDs) have been produced by doping standard polyamide alignment films with an organic conducting charge transfer complex. The doping process exploits absorption equilibrium between a solution of the dopant and the polymeric solid phase. Dopant concentration in the solid state has been evaluated by spectrophotometric analysis in the UV-visible range. Test displays with ITO electrodes and doped alignment layers have been fabricated and their performance evaluated with new techniques. It has been found that optical response is a function of dopant concentration in the alignment layer and that display performances can improve at an optimum concentration. In fact addressing hysteresis is reduced at low dopant concentration, but increases at higher concentrations.

Efficient energy harvesting for Microbial Fuel Cell dedicated to Wireless Sensor Network

Microbial Fuel Cell (MFC) is novel technology for harvesting a fully sustainable zero emissions bioenergy that, by means of dedicated electronic circuits, suitably can be used for the proper functioning of a single Wireless Sensor Network (WSN) node. MFC is a bioreactor that transforms energy stored in chemical bonds of organic compounds into electrical energy. Low-power electronic devices allow now the design of electronic systems characterized by very low energy consumption. Accordingly, this allows the use of power sources based on energy harvesting techniques that involve clean renewable sources as MFC The first section of the paper introduces technological characteristics of the cell. The second one briefly examines the gap between electrical supplying of the cell and the energy requirements of WSN nodes. The design requires the usage of a step-up DC/DC converter, so the last part of the paper deals with the problems that occur when you want realize a system including a single MFC reactor for powering a single WSN node.

Structures and organisation of an information tool dedicated to simulation and management of environmental risks

Many new services of public usefulness need geographic data to carry out their tasks. Therefore many of these services are based on Geographic Information System (GIS) products that are getting a great favour and diffusion of trade, Other services, as the instruments of navigation, the position detection on the territory of cars, make part of standard instrumentation, e.g. of a car, or represent central business of a company. At same way, they can support management systems which are characterised by a more complex architecture. We will examine the structure and organisation of a base-system that is dedicated to management of environmental risks and that easily must be specialised in a special application or a monitoring activity, In particular we will explain design lines of our platform Terrapack@ [1]. This one is structured in order to facilitate inclusion of simulation tools of environmental phenomena, guaranteeing integration of procedures and software tools [2] that are independently developed from specialists of specific field. By means of this architecture, we included and tested different tools of analysis and simulation, regarding risk management, e.g.: electromagnetic pollution in urban area [3], air pollution due to a smoke-stack [4] and forest tire propagation [5]. Moreover graphical tools are conveniently used to interpret physical data in their geographic location by establishing their mutual relation together with territorial data. Physical data can be detected online. At same way, resources can be controlled on-line and the system is conveniently oriented to manage emergency activities during an environmental disaster. Some management examples of environmental risk together with future applications will be shown and analysed.

Technical Survey About Available Technologies For Detecting Buried People Under Rubble Or Avalanches

Among all activities carried out in disaster scenarios, such as collapsed buildings, earthquakes, and avalanches, the detection and rescue of buried or trapped people have the priority. The paper aims at presenting the progress in the technological development of electronic devices and systems used to detect people buried under rubbles or avalanches. Many technologies realize detection, but only electromagnetic ones assure best results in terms of speed and accuracy of a relief, working also in a noisy environment. We can divide the methodologies using electromagnetic propagation in the three main. One is based on detection of active or passive electronic devices carried by the victim; the second one detects the body of a person as perturbation of the backscattered electromagnetic wave, due to dielectric discontinuity in the medium; the third case is based on the detection of vital signs. Both last two methodologies can be suitable for detecting people trapped under rubbles that can be free to move, also partially. More frequently, a buried person is motionless, because he is unconscious or the ruins block him. Consequently, the detection of vital signs, such as heartbeat or breathing, is the unique possible only. Performances and limits of each method is presented in the

Passive matrix SSFLC display with analogue grey levels using PTFE alignment films

Fabrication and performance of a surface stabilised ferroelectric liquid crystal display are reported. Grey shades are obtained by modulating the width of switched FLC microdomains by means of an electric field gradient distributed over the pixel, between adjacent metal columns. Such a gradient, depending on the data voltages, is achieved through a high resistance film deposited on the column glass plate. The choice of PTFE (Poly-tetra-fluoro-ethylene) alignment layers, easily deposited by friction, provides very low hysteresis and sticking effect. Morphology of alignment layers, carried out by AFM, is briefly described and evaluated. Addressing mode voltage waveforms to obtain grey shades are also reported.

Studies on Addressing Techniques for Bistable Ferroelectric Liquid Crystal Cells

Abstract A classification of all the known addressing modes is proposed and related to our simple uniform director model for the addressed FLC cell. Two addressing tricks are explained which have been found by extensive simulations with the model. Addressing experiments with our modes at 12 μs line addressing time are presented. Computer-plotted voltage-time regions of operations for several addressing modes are discussed.

Brownfield Identification: Different Approaches for Analysing Data Detected by Means of Remote Sensing

Remote sensing techniques have been used to identify different brownfield sites. Some brownfield are characterized by the presence in the area of hazardous materials and some are only a structure or land that is under-used or abandoned. Since brownfields are associated with urban wastes, such as the demolition of buildings, dangerous materials or contaminants will be involved. Hazard and health risks increase so thee is a need for administration policy to detect dangerous materials at an early stage. The paper will discuss the different techniques for identifying brownfields and for monitoring using different types of remote sensing.