On-line fault detection and diagnosis obtained by implementingneural algorithms on a digital signal processor

A measurement instrument for on-line fault detection and diagnosis is proposed. It is based on the implementation of a neural network algorithm on a processor specialized in digital signal processing and provided with suitable data acquisition and generation units. Two specific implementations are detailed. The former uses the neural-network to simulate on-line the correct system behavior, thus allowing the fault detection to be achieved by comparing the neural network output with the measured one. The latter uses the neural network to classify on-line the system as correct or faulty, thus allowing the fault detection and diagnosis to be achieved simultaneously. These two implementations are applied to detect on-line and diagnose faults on a real system in order to point out different fields of application and to highlight the performance of the measurement apparatus     

An automated self-calibrated instrument for nondestructive testing on conductive materials

An instrument for nondestructive testing in industrial environments was designed, set up, and tested. It uses fluxset magnetic sensors and is based on dedicated boards suitably set up to optimize system performances with no loss in flexibility. A self-calibration and adjustment capability was implemented, thus allowing the instrument to operate optimally in different environments. A fast Fourier transform-based algorithm was used for both probe adjustment and measurement postprocessing. The assembled instrument was then tested on specimens with known cracks, showing a very good agreement between theoretical and experimental results.     

Zeolite Advances in the Chemical and Fuel Industries: A Technical Perspective

Since zeolites were first used in petroleum processing in the 1960s [1-61], zeolite catalysis has undergone rapid and dynamic advances. The number of zeolite-related United States patents published through 1981 exceeds 5,000, and the zeolite scientific and technical literature contains over 25,000 articles [7]. Forty zeolite minerals have been identified to date, and approximately 150 synthetic materials have been reported [8].     

Experimental investigation on workers’ exposure to electromagnetic fields in proximity of magnetic resonance imaging systems

The paper presents the results of an experimental activity focused on the measurement of electromagnetic fields generated by magnetic resonance imaging systems, carried out with the purpose of assessing exposure of workers to static, low frequency and radio-frequency electromagnetic fields , as required by the EU Directive 2004/40/EC. The main contribution of the paper is that it presents a comparative study of exposure carried out during operation of the MRI system and close to the sources, with different scanning sequences and RF coils. Results show that the static magnetic field follows the theoretical values only close to the magnet due to the effect of the walls, with a few percent variation due to the operating conditions; exposure to the magnetic field in the low frequency band is mainly determined by emissions generated by the power grid at 50 Hz and by the pulses driving the gradient coils; and finally the radio-frequency band only shows contributions by the diagnostic pulses at the resonance frequency, with exposure levels usually below the limits contained in the Directive.     

The protein kinase C activators phorbol esters and phosphatidylserine inhibit neutral sphingomyelinase activation, ceramide generation, and apoptosis triggered by daunorubicin

To address the role of protein kinase C (PKC) in the regulation of ceramide production, we evaluated the impact of the PKC activators 12-O-tetradecanoylphorbol-13-acetate and phosphatidylserine on the apoptotic signaling pathway triggered by the chemotherapeutic drug daunorubicin. Treatment of U937 and HL-60 cells with 0.5-1 microM daunorubicin induced a greater than 30% activation of neutral sphingomyelinase activity within 4-10 min with concomitant sphingomyelin hydrolysis and ceramide generation. Activation of PKC by 12-O-tetradecanoylphorbol-13-acetate and phosphatidylserine inhibited daunorubicin-induced neutral sphingomyelinase activation, sphingomyelin hydrolysis, ceramide generation, and apoptosis. The apoptotic response could be restored by the addition of 25 microM cell-permeant C6-ceramide. In conclusion, PKC emerges as a potentially critical negative regulator of the anthracycline-activated sphingomyelin-ceramide apoptotic pathway.     

Achieving ultra low emissions in a commercial 1.4 MW gas turbine utilizing catalytic combustion

The drive to achieve low emissions from gas turbines has been an ongoing challenge for over 30 years with the reduction of NO_x levels representing the most difficult issue. Catalytic combustion represents the technological approach that can achieve the lowest level of NO_x, in the range of 3 ppm and lower depending on the combustion system design. The program to develop a catalytic combustion technology that can achieve ultra low levels of NO_x, CO and unburned hydrocarbons (UHCs), applicable to a wide range of gas turbine systems and with long term durability is described. The technological approach is to combust only a portion of the fuel within the catalyst with the remaining fuel combusted downstream of the catalyst allowing the catalyst to operate at a low temperature and thus obtaining good long term catalyst durability. This catalytic combustion approach is then applied to a 1.4 MW gas turbine to demonstrate feasibility and to obtain real field experience and to identify issues and areas needing further work. The success of this demonstration lead to a commercial combustor design. This combustor and the final commercial package is described and the performance specifications discussed.     

Compact CMOS implementation of a low‐power,current‐mode programmable cellular neural network

We report on the design and characterization of a full‐analog programmable current‐mode cellular neural network (CNN) in CMOS technology. In the proposed CNN, a novel cell‐core topology, which allows for an easy programming of both feedback and control templates over a wide range of values, including all those required for many signal processing tasks, is employed. The CMOS implementation of this network features both low‐power consumption and small‐area occupation, making it suitable for the realization of large cell‐grid sizes. Device level and Monte Carlo simulations of the network proved that the proposed CNN can be successfully adopted for several applications in both grey‐scale and binary image processing tasks. Results from the characterization of a preliminary CNN test‐chip (8×1 array), intended as a simple demonstrator of the proposed circuit technique, are also reported and discussed. Copyright © 2001 John Wiley & Sons, Ltd.     

Fluid dynamic performances of traditional and alternative jet fans in tunnel longitudinal ventilation systems

This paper presents the results of a numerical investigation carried out on an alternative jet fan, known in literature like Banana Jet®, and it compares its fluid dynamic performances to traditional axial ventilation systems. The alternative jet fan is equipped with inlet/outlet sections inclined at a fixed pitch angle (α) toward the tunnel floor. This approach establishes an alternative solution that is able to provide a safety level equivalent to the traditional solution, in different scenarios. Both systems are installed in an one-way tunnel and two different scenarios (without vehicles and with traffic jam) are considered, in event of fire. The fire was simulated setting heat flux on Heavy Good Vehicle (HGV) surface and comprehensive of radiative heat flux. Computational Fluid-Dynamic (CFD) are applied to simulate the ventilation in the unidirectional tunnel through k–ε model, including temperature fields. The results show, for both scenarios, the existence of an optimal pitch angle which offers advantages in comparison with the traditional system (α = 0°) in terms of plant and running costs. In the next paper, the influence of the radiative heat flux for the optimal pitch angle will be explicitly considered.     

Development of a fabrication technology for double-sided AC-coupled silicon microstrip detectors

We report on the development of a fabrication technology for double-sided, AC-coupled silicon microstrip detectors for tracking applications. Two batches of detectors with good electrical figures and a low defect rate were successfully manufactured at IRST Laboratory. The processing techniques and the experimental results obtained from these detector prototypes are presented and discussed.