Search results for "AFC"

Survival and gene expression under different temperature and humidity regimes in ants

2017

Short term variation in environmental conditions requires individuals to adapt via changes in behavior and/or physiology. In particular variation in temperature and humidity are common, and the physiological adaptation to changes in temperature and humidity often involves alterations in gene expression, in particular that of heat-shock proteins. However, not only traits involved in the resistance to environmental stresses, but also other traits, such as immune defenses, may be influenced indirectly by changes in temperature and humidity. Here we investigated the response of the ant F. exsecta to two temperature regimes (20 degrees C & 25 degrees C), and two humidity regimes (50% & 75%), for…

Lavtemperatur brenselceller

2005

Dokumentet er en del av en eksamensoppgave i MEF4200 Energimaterialer ved UiO høsten 2004. Som del av eksamen i emnet MEF4200 Energimaterialer ved Universitetet i Oslo (UiO) høsten 2004 var oppgaven å skrive en populærvitenskapelig artikkel for avgangselever i videregående skole. Artikkelen presenteres her og omhandler lavtemperatur brenselceller. De brenselcelletypene som beskrives er alkaliske brenselceller, PEM-brenselceller og metanolbrenselceller, alle med en driftstemperatur på normalt under 100 °C, og deres bruksområder.

CAD-R. Cuestionario de afrontamiento al dolor crónico: análisis factorial confirmatorio. ¿Hay diferencias individuales en sexo, edad y tipo de dolor?

2017

espanolRESUMEN Introduccion: Se presenta una revision del CAD-R (Cuestionario de afrontamiento al dolor reducido) (1) en una muestra de 4.389 pacientes diagnosticados con dolor cronico derivada de un estudio multicentrico de toda Espana (2). Material y metodo: Se analiza la estructura factorial mediante analisis factorial exploratorio (AFE) y confirmatorio (AFC), asi como la fiabilidad (consistencia interna y test retest a los tres meses, esta ultima sobre 2.825 pacientes). Se ponen a prueba cuatro modelos constatando que las estrategias de primer orden correlacionadas son las que aportan mejores indices de ajuste. Resultados: Tanto los indices de consistencia interna como los test-retest r…

Fractal Dimension Logarithmic Differences Method for Low Voltage Series Arc Fault Detection

2021

Series arc faults introduce singularities in the current signal and changes over time. Fractal dimension can be used to characterize the dynamic behaviour of the current signal by providing a degree of signal chaos. This measure of irregularity exhibits changes in signal behaviour that can suitably be used as a basis for series arc fault detection. In this paper, an efficient low voltage series arc fault detection method based on the logarithmic differences of the estimate of the fractal dimension of the current signal using the multiresolution length-based method is presented. The discrete wavelet transform and the hard thresholding denoising with the universal threshold are also used. Exp…

A set of indicators for arc faults detection based on low frequency harmonic analysis

2016

In this paper a novel set of indicators is presented for arc faults detection in electrical circuits. The indicators are defined starting from an experimental characterization of the arc fault phenomenon and the study of the arcing current in several test conditions, which were chosen in accordance with the UL 1699 Standard requirements. The proposed parameters are measured by means of a high resolution low frequency spectral analysis of the arcing current, which allows to achieve a good spectral resolution even with short observation windows.

Arc Fault Detection Method Based on CZT Low-Frequency Harmonic Current Analysis

2017

This paper presents a method for the detection of series arc faults in electrical circuits, which has been developed starting from an experimental characterization of the arc fault phenomenon and an arcing current study in several test conditions. Starting from this, the authors have found that is it possible to suitably detect arc faults by means of a high-resolution low-frequency harmonic analysis of current signal, based on chirp zeta transform, and a proper set of indicators. The proposed method effectiveness is shown by means of experimental tests, which were carried in both arcing and nonarcing conditions and in the presence of different loads, chosen according to the UL 1699 standard…

Experimental characterization of series arc faults in AC and DC electrical circuits

2014

This paper presents an experimental characterization of the arc fault phenomenon, for both AC and DC systems, focusing the attention on series arcs. The aim of the study is to find some current characteristics, which can be significant for the purpose of arc detection. The arcing current signal is analyzed in both time and frequency domain. For the AC analysis, the test conditions are chosen in accordance with the “unwanted tripping tests” and the “operation inhibition tests” reported in the Standard UL 1699. The DC study is carried out on the currents waveforms acquired during some on-field tests on a PV plant. Starting from the study herein presented, the authors have found that is it pos…

Material, mental, and moral progress : American conceptions of civilization in late 19th century studies on "things Chinese and Japanese"

2015

Fogging effect correction of Gafchromic HD-V2 film response for its use in high-dose radiotherapy

2020

GAFChromic® HD-V2 film is a reliable dose measurement device, thin, flexible, inexpensive, simple to use and easy to analyze. The response in terms of net absorbance with respect to absorbed dose was found to be linear in a large dose range, which supports the feasibility of using the film dosimeters in many applications, such as radiotherapy. For its use, a "fogging" effect must be take into account since film response changes with time. To determine a calibration curve valid for any time, fogging effect was investigated for more than 400 days. A correction procedure allows the use of HD-V2 film dosimeters in high-dose radiotheraphy, as brachytherapy, and quality assurance (QA) procedures.

Response of GAFChromic® HD-V2 film dosimeter in 10-300 Gy dose range for radiation testing of electronic devices

2019

The study reported in this paper aimed to investigate the response of a GAFChromic? HD-V2 film dosimeter in the dose range between 10 and 300 Gy, normally used to perform irradiation tests on electronic devices with a 60Co gamma-ray irradiator. The well-defined linearity of response in terms of absorbance as a function of absorbed dose, easiness of handling and data analysis of irradiated dosimeters, reproducibility, stability, and insensitivity to visible light and most of the environmental parameters, make HD-V2 film a flexible, inexpensive and reliable dose measurement device. The study has shown a fogging effect of the dosimeter response since its value changes over time. Strategies and…