Search results for " reliability"
showing 10 items of 557 documents
A Multi objective inventory model for short food supply chains
2017
Over the past 50 years, vertically integrated multinationals dominated global food markets by providing huge product diversity at low prices. Such systems are characterized by long supply chains capable of achieving high cost efficiencies resulting from the use of cheap raw materials, high chemical inputs, industrial shelf-life extension processes, economies of scale and mechanization. This dominant position on the market, however, has been achieved at a heavy cost on the global environment, generated by massive food wastage, and by a steady supply of fossil fuels. For such reasons, global supply chains are considered unsustainable and new food systems are being promoted in order to replace…
Association between physical, psychological and social frailty and health-related quality of life among older people
2019
Abstract Background Studies on the association between frailty and health-related quality of life (HRQoL) are scarce and show contradictory results. This study aimed to evaluate the association between physical, psychological and social frailty and HRQoL among community-dwelling older people. Methods A cross-sectional study was performed with baseline data collected in 2015 from the Urban Health Centers Europe (UHCE) project in five European countries, the United Kingdom, Greece, Croatia, The Netherlands and Spain. A total of 2325 participants were included in the baseline measurements of the Urban Health Centers Europe project; 2167 participants (mean age = 79.7; SD=5.6) were included in t…
Seismic vulnerability of structures and infrastructures: Strategies for assessment and mitigation
2017
Seismic engineering is constantly looking for new strategies and methods that provide designers with the opportunity to get more and more efficient solutions both from the performance and from the economic point of view. In this context, the scientific community is called not to miss its support and to face the new challenges coming from the observation of the damage caused by the recent earthquakes. This Special Issue of “Ingegneria Sismica” collects some works focusing the theme of the seismic vulnerability, some of them specifically refer to mitigation strategies while others address modeling strategies. Obviously, for the multiplicity of aspects involving the theme of "seismic vulnerabi…
Metrological performances of voltage and current instrument transformers in harmonics measurements
2018
In the new electrical system scenario, the increasing presence of non-linear loads and renewable energy sources makes the measurement of harmonics an essential task. The accuracy of harmonic measurement firstly depends on the used instrument transformers for voltage and current sensing. Since the behavior of instrument transformers in non-sinusoidal conditions is not always well defined, this paper presents an experimental study on the metrological performances of current and voltage instrument transformers (CTs and VTs) in the presence of harmonics. Proper tests procedures are defined and measurement setups are developed for both CTs and VTs calibration. The analysis is carried out by usin…
Probabilistic Flood Hazard Mapping Using Bivariate Analysis Based on Copulas
2017
This study presents a methodology to extract probabilistic flood hazard maps in an area subject to flood risk, taking into account uncertainties in the definition of design hydrographs. Particularly, the authors present a new method to produce probabilistic inundation and flood hazard maps in which the hydrological input (i.e., synthetic flood design event) to a 2D hydraulic model has been obtained by using a bivariate statistical analysis (copulas) to generate flood peak discharges and volumes. This study also aims to quantify the contribution of boundary conditions’ uncertainty in order to evaluate the effect of this uncertainty source on probabilistic flood hazard mapping. Different comb…
Leadership and employees’ perceived safety behaviours in a nuclear power plant: A structural equation model
2011
Leadership is considered an essential element in guaranteeing the safe running of organizations. The purpose of the present study is to find out how leader behaviours influence employees' safety behaviours (perceived safety behaviours) in the nuclear field. In an attempt to answer this question, the authors of this research have considered the way this influence is exercised, taking into consideration some important factors like safety culture and safety climate. To achieve this, the empowerment leadership model, based on a behavioural approach to leadership, was used. The sample was made up of 566 employees from a Spanish nuclear power plant. The results indicated that when safety culture …
Profiling Safety Behaviors: Exploration of the Sociocognitive Variables that Best Discriminate Between Different Behavioral Patterns
2012
This study combines contributions from both safety climate literature and prominent social influence theories. It was developed to identify the combination of sociocognitive variables that differentiate between different profiles of safety behaviors. This empirical approach has hardly been explored in the literature on behavioral aspects related to safety. The research setting for this study was a transportation company (N= 356). The results of discriminant analysis showed that different combinations of dispositional and situational influences may lead to diverse profiles of compliance and proactive safety behaviors. Perceived behavioral control was revealed to be the variable that best dif…
Reliability and Retention Study of Nanocrystal Cell Array
2002
We have studied nanocrystal memory arrays with 2.56 × 105 cells (256kb) in which Si nanocrystals have been obtained by CVD deposition on a 4nm tunnel oxide. The cells in the array are programmed and erased by electron tunneling through the SiO2 dielectric. We find that the threshold voltage distribution has little spread. In addition the arrays are also very robust with respect to drain stress and show good retention.
Psychometric properties and factor structure of the Satisfaction with Life Scale in an elderly Portuguese retirees students sample
2017
El objetivo principal de este estudio ha sido analizar las propie- dades psicométricas de la escala de Satisfacción con la Vida (SWLS) en una muestra de 363 estudiantes jubilados pertenecientes a varias universidades portuguesas. El 70% de los participantes eran mujeres frente a un 30% de hombres, con una media de edad de 67 años (SD = 7.59) y un rango de edad comprendido entre 48 y 90 años. Se realizó un Análisis Factorial Ex- ploratorio con R Commander y un Análisis Factorial Confirmatorio con Amos 18.0. El modelo que obtuvo un mejor ajuste estaba compuesto por un único factor. El índice de consistencia interna de la escala en su conjun- to fue de .777. En cuanto a la validez concurrente,…
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.