Search results for " Reliability."
showing 10 items of 551 documents
Skewness and kurtosis of 1/f noise in semiconductor devices
2000
An experimental investigation of the third and fourth moments of the 1/f noise of two different electronic devices is reported. The skewness and the kurtosis of the noise voltage data are estimated. Although the devices under investigation have similar noise power spectral density, the time waveforms are shown to have slightly different statistical properties. In both cases, a small deviation from Gaussian distribution is observed.
Path Integral Methods for the Probabilistic Analysis of Nonlinear Systems Under a White-Noise Process
2020
Abstract In this paper, the widely known path integral method, derived from the application of the Chapman–Kolmogorov equation, is described in details and discussed with reference to the main results available in literature in several decades of contributions. The most simple application of the method is related to the solution of Fokker–Planck type equations. In this paper, the solution in the presence of normal, α-stable, and Poissonian white noises is first discussed. Then, application to barrier problems, such as first passage problems and vibroimpact problems is described. Further, the extension of the path integral method to problems involving multi-degrees-of-freedom systems is anal…
Compatibility, effectiveness and susceptibility to degradation of alkoxysilane-based consolidation treatments on a carbonate stone
2021
Abstract Alkoxysilane-based consolidation treatment are commonly employed in restoration and conservation works of Cultural Heritage buildings. However, their poor affinity to carbonate stones is well-known. In this paper, we evaluate three consolidant treatments (two of them modified to incorporate hydrophobic or photocatalytic properties), formulated to circumvent this drawback and their cracking during drying, through a surfactant-assisted synthesis. The consolidants were applied on Noto stone, a biocalcarenite (~95% CaCO3 ) employed in numerous Cultural Heritage buildings of Southern Italy. A comprehensive validation of the three consolidants, compared to a commercial TEOS based consoli…
Iron-containing phases in metallurgical and coke dusts as well as in bog iron ore
2017
Abstract Several samples of dusts from steel and coke plants (collected mostly with electro filters) were subjected to the investigation of content of mineral phases in their particles. Additionally, sample of bog iron ore and metallurgical slurry was studied. Next, the magnetic susceptibility of all the samples was determined, and investigations of iron-containing phases were performed using transmission Mössbauer spectrometry. The values of mass-specific magnetic susceptibility χ varied in a wide range: from 59 to above 7000 × 10−8 m-3·kg−1. The low values are determined for bog iron ore, metallurgical slurry, and coke dusts. The extremely high χ was obtained for metallurgical dusts. The …
Analyses of single- and two-phase flow pressure drops in helical pipes using a modified RELAP5 code
2012
Abstract Thermal fluid dynamics analyses on single- and two-phase flows in helical pipes of steam generators to be used in Generation III and IV nuclear reactors have been performed. The study concerned with experimental activities as well code simulations carried out in the framework of a collaboration between the Department of Energetics of the Polytechnic of Torino and the Department of Energy of the University of Palermo. The goal was the validation of models implemented in Relap5/Mod3.2β thermal–hydraulic advanced code to simulate the hydrodynamic behaviour of helical pipe components in spite of the one-dimensional nature of the code. It is shown that much of the experimental data obta…
Computational and experimental studies of the flow field near the beam entrance window of a liquid metal target
2014
Abstract After the first world liquid metal target has been successfully operated at the SINQ facility at the Paul Scherrer Institut (PSI) for 6 months. The idea of having a reliable target with a bypass flow for cooling the beam entrance window, but with the bypass flow not driven by a separate pump, was examined within the project called LIMETS (Liquid Metal Target for SINQ). In designing of liquid metal targets, turbulence modelling is of high importance due to lack in methods for measuring the spatial distribution of flow and turbulence characteristics. In this study, validation of different turbulence models were performed in water model with hemispherical geometry using particle image…
A semi-empirical approach for predicting two-phase flow discharge through branches of various orientations connected to a horizontal main pipe
2010
Abstract The subdivision of two-phase flow in branching conduits consisting of a large horizontal main pipe with upward, downward, or lateral branches of reduced diameter is of great interest in various technological fields. For example, these conduits are important in light-water nuclear reactors (LWRs) in the case of a small break loss-of-coolant accident (SBLOCA) in a leg of the reactor's primary coolant loops, as well as for breaks or valve malfunctions in a large pipeline. In these kinds of circumstances, the relevant phenomenology often involves phase stratification coupled with possible liquid entrainment or gas pool-through phenomena. Therefore, these phenomena were studied in depth…
Sensitivity Analysis of the MASLWR Helical Coil Steam Generator Using TRACE
2011
Accurate simulation of transient system behavior of a nuclear power plant is the goal of systems code calculations, and the evaluation of a code's calculation accuracy is accomplished by assessment and validation against appropriate system data. These system data may be developed either from a running system prototype or from a scaled model test facility, and characterize the thermal hydraulic phenomena during both steady state and transient conditions. The identification and characterization of the relevant thermal hydraulic phenomena, and the assessment and validation of thermal hydraulic systems codes, has been the objective of multiple international research programs. The validation and…
The measuring method for tests of horizontal two-phase gas–liquid flows, using optical and capacitance tomography
2009
Abstract The paper presents a measurement method in testing horizontal two-phase gas–liquid flows. It also describes the test stand including two tomography measurement systems. The optical and capacitance tomography systems can be used for measurements at the same time. It is necessary to apply two tomography systems working at the same time because of complexity of phenomena occurring in two-phase flows, and a wide range of applicability of the presented method. The optical tomography system in which a tested object is illuminated from five projections. The measurement of luminous intensity is changed into a discrete signal (0 or 1) in the detectors including 64 optical sensors. Next, the…
Investigation of corrosion defects in titanium by positron annihilation
2015
Abstract The positron annihilation method was used to study the formation of defects in titanium samples during their corrosion in the vapor of a 3% HCl solution. In particular, the distribution of defects depending on the distance from the corroding surface and the impact of an external magnetic field on the concentration of vacancies forming during the corrosion of titanium layers close to the surface were determined.