Search results for "Gradation"

Desertification and Water Scarcity as a Security Challenge in the Mediterranean

2009

There is a new perception of a global dimension: environmental security. The protection of our fixed and shared environment is gradually coming to people’s attention as an obligatory requirement for equitable development, in order to prevent disasters related to environmental security and to avoid conflicts. The Euro-Mediterranean Region is also immersed in this general trend partly as a consequence of more frequent severe environmental events, such as forest fires, floods and landslides, droughts, torrential rains, heat waves and water scarcity. The Southern and Eastern shores of the Mediterranean undergo even more harsh environmental impacts affecting the stability of the land, its capaci…

Stochastic modeling and prediction of catalytic converters degradation

2009

This paper proposes a stochastic model for describing the degradation process of catalytic converters over time, where the degradation is indirectly measured through the emission of complex hydrocarbons (HC) in legislated driving cycles. The proposed model is the superposition of two processes, the former being a dependent increments process which describes the actual degradation process, and the latter a white noise process which models the experimental errors. In particular, the proposed model assumes that the degradation growth in a small usage interval depends on the degradation level at the beginning of the interval, rather than on the age of the converter. The model has been applied t…

Genome Sequence of Rhodococcus sp. Strain BCP1, a Biodegrader of Alkanes and Chlorinated Compounds

2013

Rhodococcus sp. strain BCP1 (DSM 44980) co-metabolizes chlorinated compounds and mineralizes a broad range of alkanes being highly tolerant to these toxic chemicals. Here, we present the high-quality draft genome sequence of strain BCP1 consisting of 6,231,823 bp, with a G+C content of 70.4%, 5,902 protein-coding genes, and 58 RNAs genes. Rhodococcus genus comprises Gram-positive, non-sporulating, aerobic bacteria that are widely distributed in the environment (1). Rhodococcus sp. strain BCP1 (formerly: Rhodococcus aetherovorans strain BCP1, DSM 44980) was selected from an aerobic butane-utilizing consortium as the prevailing isolate able to co-metabolize chloroform, vinyl chloride and tric…

An analytical study of mixed backoff schemes for QoS differentiation in wireless LAN

2009

In this paper, we propose an analytical model to evaluate performances of a wireless network composed by two groups of nodes using two different backoff schemes for channel access. The two different backoff schemes are used for QoS differentiation in term of priority. Our analysis results show that the priority group can have its performances enhanced, in term of saturation throughput and delay, without significant degradation of normal group nodes performances. This enhancement is also noticed for throughput efficiency at system level.

A computational framework for low-cycle fatigue in polycrystalline materials

2021

Abstract A three-dimensional framework for low-cycle fatigue analysis of polycrystalline aggregates is proposed in this work. First, a cohesive law coupling plasticity and damage is developed for modelling cycle-by-cycle degradation of material interfaces up to complete de-cohesion and failure. The law may model both quasi-static degradation under increasing monotonic load and degradation under cyclic loading, through a coupled plasticity-damage model whose activation and flow rules are formulated in a thermodynamically consistent framework. The proposed interface laws have been then implemented and coupled with a multi-region boundary element formulation, with the aim of analysing low-cycl…

Temperature profiles of field-aged multicrystalline silicon photovoltaic modules affected by microcracks

2021

In this work, the temperature sensitivities of field-aged multicrystalline silicon PV modules affected by microcracks are investigated. It is found that the temperature coefficient of efficiency of all modules has increased more than 10 times over the 20 years period, mainly due to a degradation in the temperature coefficients of fill factor. Temperature coefficient of efficiency of PV modules affected by microcracks changed from -0.44 %/ °C to -1.51 %/°C under solar irradiance conditions at 1010 - 1030 W/m2. Inconsistent values for the Evans–Floschuetz efficiency ratio versus temperature plots for the microcrack affected modules were also observed.

Non-uniform Sediment Transport Estimation in Non-equilibrium Situations: Case Studies

2014

Abstract Quantitative estimate of sediment transport in alluvial channels is one of the most important task in river engineering. Even today, numerical models of sediment transport processes are confronted with some difficulties, often of conceptual nature. One of these difficulties is the simulation of non-uniform sediment transport in non-equilibrium situations, which requires the characterization of the ability of the alluvial system to immediately overcome the variations of the sediment boundary conditions. In this work a 1-D numerical model, which includes a new expression of the so-called “adaptation coefficient”, has been applied to test its capability to simulate the transient bed p…

Extended Validation of Dynamic Irreversible Thermoporation: A Novel Thermal Process for Microbial Inactivation

2015

A novel thermal treatment for microorganism inactivation, characterized by a very rapid temperature increase (up to 30°C/s) and a low final temperature (up to 65°C) maintained for a relatively short holding time, has been recently presented and tested by the authors, showing microbial load reduction greater than 5 log units against several common bacteria and yeasts. With the aim of extending the possible use of the new thermal treatment to a wider microorganisms class, in this work the dynamic irreversible thermoporation (DIT) treatment was further tested on a well-known thermoresistant strain, the Enterococcus hirae: The results of these new experimental tests confirmed the reliability of…

Le statue rinascimentali di palazzo Abatellis: caratterizzazione delle dorature e dei pigmenti tramite spettrometria XRF.

2010

Improvement of photo-stability of LLDPE-based nanocomposites

2006

LLDPE-based nanocomposites undergo faster photo-oxidation than the unfilled matrix and the extent of their physical properties deterioration, namely elongation at break and tensile strength, is dependent on the organo-nanoclay loading. The observed acceleration is not due to faster photo-oxidation but rather due to a reduction of the oxidation induction time. The presence in the organoclays of trace amounts of metal ions may be promoting catalytic photodegradation. While UV absorbers provide useful protection, use of a metal deactivator has been found to greatly enhance the photo-stability of the LLDPE-based nanocomposites. Combinations of a metal deactivator and UV absorber yield synergist…