Influence of Humidity on Fiber Bragg Grating Sensors

We demonstrate the influence of the relative humidity (RH) on the wavelength of fiber Bragg grating sensors (FBGS), performing tests with five FBGS at different humidity and temperature conditions. These tests were performed in a climate chamber whose RH changes according to a scheduled profile from 30% to 90%, in steps of 10%. These profiles were repeated for a wide range of temperatures from to , in steps of . Two different types of instrumentation methods have been tested, spot welding and epoxy bonding, in two different materials, steel and carbon fiber reinforced polymer (CFRP). We discuss the results for each type of sensor and instrumentation method by analyzing the linearity of the Bragg wavelength with RH and temperature.

Influence of Humidity on Fiber Bragg Grating Sensors

We demonstrate the influence of the relative humidity (RH) on the wavelength of fiber Bragg grating sensors (FBGS), performing tests with five FBGS at different humidity and temperature conditions. These tests were performed in a climate chamber whose RH changes according to a scheduled profile from 30% to 90%, in steps of 10%. These profiles were repeated for a wide range of temperatures from 10 degrees C to 70 degrees C, in steps of 10 degrees C. Two different types of instrumentation methods have been tested, spot welding and epoxy bonding, in two different materials, steel and carbon fiber reinforced polymer (CFRP). We discuss the results for each type of sensor and instrumentation method by analyzing the linearity of the Bragg wavelength with RH and temperature.

Running Pace Decrease during a Marathon Is Positively Related to Blood Markers of Muscle Damage

Background: Completing a marathon is one of the most challenging sports activities, yet the source of running fatigue during this event is not completely understood. The aim of this investigation was to determine the cause(s) of running fatigue during a marathon in warm weather. Methodology/Principal Findings: We recruited 40 amateur runners (34 men and 6 women) for the study. Before the race, body core temperature, body mass, leg muscle power output during a countermovement jump, and blood samples were obtained. During the marathon (27 uC; 27% relative humidity) running fatigue was measured as the pace reduction from the first 5-km to the end of the race. Within 3 min after the marathon, the same pre-exercise variables were obtained. Results: Marathoners reduced their running pace from 3.5 6 0.4 m/s after 5-km to 2.9 6 0.6 m/s at the end of the race (P,0.05), although the running fatigue experienced by the marathoners was uneven. Marathoners with greater running fatigue (. 15% pace reduction) had elevated post-race myoglobin (1318 6 1411 v 623 6 391 mg L21; P,0.05), lactate dehydrogenase (687 6 151 v 583 6 117 U L21; P,0.05), and creatine kinase (564 6 469 v 363 6 158 U L21; P = 0.07) in comparison with marathoners that preserved their running pace reasonably well throughout the race. However, they did not differ in their body mass change (23.1 6 1.0 v 23.0 6 1.0%; P = 0.60) or post-race body temperature (38.7 6 0.7 v 38.9 6 0.9 uC; P = 0.35). Conclusions/Significance: Running pace decline during a marathon was positively related with muscle breakdown blood markers. To elucidate if muscle damage during a marathon is related to mechanistic or metabolic factors requires further investigation.

Fiber Bragg Gratings, IT Techniques and Strain Gauge Validation for Strain Calculation on Aged Metal Specimens

This paper studies the feasibility of calculating strains in aged F114 steel specimens with Fiber Bragg Grating (FBG) sensors and infrared thermography (IT) techniques. Two specimens have been conditioned under extreme temperature and relative humidity conditions making comparative tests of stress before and after aging using different adhesives. Moreover, a comparison has been made with IT tecniques and conventional methods for calculating stresses in F114 steel. Implementation of Structural Health Monitoring techniques on real aircraft during their life cycle requires a study of the behaviour of FBG sensors and their wiring under real conditions, before using them for a long time. To simulate aging, specimens were stored in a climate chamber at 70 degrees C and 90% RH for 60 days. This study is framed within the Structural Health Monitoring (SHM) and Non Destructuve Evaluation (NDE) research lines, integrated into the avionics area maintained by the Aeronautical Technologies Centre (CTA) and the University of the Basque Country (UPV/EHU).

Modelo de representación y difusión de cavidades. Cueva de Praileaitz. Deba, Gipuzkoa

[ES] Este artículo está basado en el siguiente proyecto que también puede ser consultado en este repositorio:

Análisis y mejora de un sistema de refrigeración en el laboratorio LCCE en Vitoria-Gasteiz

[ES]El objetivo de este proyecto es el análisis y mejora de un sistema de refrigeración en el Laboratorio de Control de Calidad en la Edificación (LCCE) del Gobierno Vasco/Eusko Jaurlaritza en Vitoria-Gasteiz. Dicho equipo, después de un uso continuado, sufre una colmatación por la formación de hielo en el intercambiador de calor. Por ello, en el siguiente texto se proponen alternativas para acabar con la formación del hielo y poder seguir con el funcionamiento normal del equipo. Se va a proceder a modificar el control de la instalación y también parte de la instalación eléctrica y sensórica. Para ello, se han usado las instalaciones del laboratorio LCCE así como la ayuda de los trabajadores del mismo. Todos los datos del sistema de refrigeración (temperaturas, caudal, humedad, etc...) se toman de un documento Excel que es guardado automáticamente al realizar los ensayos. El trabajo se ha estructurado de la siguiente manera: Introducción y descripción del sistema Análisis de las alternativas y la metodología utilizada Conclusiones, fuentes de información y anexos

Bilboko IGET-eko berotze, aireztatze eta aire girotu sistemaren analisia.

[EU]Proiektu honen helburua, Makina eta Motor Termiko sailean dagoen aire girotu, aireztatze eta berogailu sistema elikatzen duen makinaren analisi bat egitea da. Makina behar duen bezala lan egiten duen eta bulegoetan airearen kalitatea bermatzen baden ikusiko dugu. Hortaz, testu honek aurreko egoerak betetzen diren edo ez argituko du eta ezezko kasua izatekotan funtzionamendu normalera bueltatzeko aukerak proposatuko dira. Horretarako neurketak bai bulegoetan egingo dira eta baita makinan ere. Datu hauek (tenperatuak, emariak, hezetasuna, eta abar…) Excel horri batean gordeko dira gero taulak lortzeko eta errazago identifikatzeko non dauden arazoak. Lana hurrengo eran egituratu da: Sistemaren sarrera eta deskribapena. Neurketak egiteko metodologia eta sistemaren analisia. Konklusioak, informazio iturriak eta eranskinak.

The effect of low solubility organic acids on the hygroscopicity of sodium halide aerosols

In order to accurately assess the influence of fatty acids on the hygroscopic and other physicochemical properties of sea salt aerosols, hexanoic, octanoic or lauric acid together with sodium halide salts (NaCl, NaBr and NaI) have been chosen to be investigated in this study. The hygroscopic properties of sodium halide sub-micrometre particles covered with organic acids have been examined by Fourier-transform infrared spectroscopy in an aerosol flow cell. Covered particles were generated by flowing atomized sodium halide particles (either dry or aqueous) through a heated oven containing the gaseous acid. The obtained results indicate that gaseous organic acids easily nucleate onto dry and aqueous sodium halide particles. On the other hand, scanning electron microscopy (SEM) images indicate that lauric acid coating on NaCl particles makes them to aggregate in small clusters. The hygroscopic behaviour of covered sodium halide particles in deliquescence mode shows different features with the exchange of the halide ion, whereas the organic surfactant has little effect in NaBr particles, NaCl and NaI covered particles experience appreciable shifts in their deliquescence relative humidities, with different trends observed for each of the acids studied. In efflorescence mode, the overall effect of the organic covering is to retard the loss of water in the particles. It has been observed that the presence of gaseous water in heterogeneously nucleated particles tends to displace the cover of hexanoic acid to energetically stabilize the system.

Energy retrofits in social housing. Analysis of its thermal behaviour.

468 p.