Search results for "Forced"

Analytical solution for the transient response of symmetric magnetoelectric laminated beams

2010

In this paper an analytical solution is presented for the forced vibration problem of magnetoelectric symmetric laminated beams. In deriving the mathematical model the Timoshenko’s beam theory is used and the electric and magnetic fields are assumed to be quasi-static. The model is written for a magnetoelectric sensing device by applying proper magnetoelectric boundary conditions on the beam top and bottom surfaces. The model highlights that the magneto-electro-mechanical couplings affect the bending stiffness and that the magnetoelectric inputs can be treated as equivalent bending moments. Forced vibration analyses are presented to assess the reliability of the solution.

Implementation of a fast and low cost IR-NDT technique by means of a Square Pulse modulated Lock-In Thermography

2012

This work describes the development of an IR-NDT procedure based on a lock-in signal treatment in the frequency domain to obtain phase-contrast defect signatures. Heat stimulation is obtained by periodically shattering a common low-power halogen lamp. The delivered heat is then modulated as a train of square waves with multi-frequency harmonic content. The proposed lock-in algorithm is able to selectively retrieve phase and amplitude information at various frequencies of the acquired temperature, acting also as a narrow band filter to improve defect-signature to noise ratio. The procedure is implemented and evaluated by means of low cost IR equipment to investigate artificially defected thi…

Vulnerability to Forced Labour and Trafficking: The case of Romanian women in the agricultural sector in Sicily

2015

This paper focuses on labour and sexual exploitation faced by Romanian female workers employed in the agricultural sector in Ragusa, Sicily, Italy. Drawing on fieldwork conducted in 2013 and 2014 with Romanian female farm workers in Ragusa, the paper identifies factors that contribute towards their vulnerability to exploitation. By paying specific attention to the experiences of women who are mothers with dependent children, we look at structural factors that increase their vulnerability and consider how this vulnerability ‘forces’ women into situations whereby they effectively accept and/or submit to abuse. We also highlight how European Union (EU) citizenship does not automatically protec…

ASSESSMENT OF THE STRENGTH OF CARBON-CARBON COMPOSITES IN CROSS-BENDING AND SHEARING

2015

Numerical Calibration of a Simplified Model for FRP Confinement of Columns

2018

This paper presents the calibration of a simplified analytical model for concrete columns confined by fiber reinforced polymer (FRP) jackets. The model allows evaluating the increase of strength, ductility and dissipated energy without defining the lateral confinement pressure and it can be easily extended for the assessment of FRP confinement in design applications. This model was obtained by a simplified procedure based on the best fit of experimental data available in the literature and the coefficient of determination (R2) was evaluated in order to estimate the accuracy of the regression analysis. A numerical database resulting from finite element (FE) analyses was compiled and reported…

Simplified analytical models for compressed concrete columns confined by FRP and FRCM system

2017

In order to consider the response of concrete columns confined by FRP and FRCM system, proper models have to be formulated. In this context the present paper shows a generalized criterion for the determination of the increase in strength, in ductility and in dissipated energy for varying corner radius ratio of the cross section and fiber volumetric ratio. The procedure is based on the best fitting of several experimental data and unlike the usual empirical approaches available in the literature, the proposed technique relates the confinement effectiveness to a single parameter representative of the relative stiffness between the original concrete core and the reinforcement system. Furthermo…

Airway obstruction in relation to symptoms in chronic respiratory disease—a nationally representative population study

2000

Abstract We examined the severity of airway obstruction and the occurrence of respiratory symptoms in a large, nationally representative population sample and in a subgroup of subjects with chronic bronchitis and/or emphysema to obtain information for developing national prevention and treatment strategies for these diseases. The study population comprised of 7217 randomly selected subjects (aged 30 years and older) who participated in a comprehensive health examination survey. The ‘cases' were subjects diagnosed as having chronic bronchitis and/or emphysema. The survey methods comprised of questionnaires, interviews, physical measurements, including spirometry, and clinical examinations. I…

Subclinical impairment of lung function is related to mild cardiac dysfunction and manifest heart failure in the general population.

2016

Lung function impairment has previously been related to heart failure, although no overt cardiovascular or structural heart disease is present. The extent to which pulmonary function is related to subclinical left ventricular impairment in the general population remains to be investigated.15010 individuals from the general population (mean age 55±11years, 50.5% men) in the Gutenberg Health Study underwent spirometry, transthoracic echocardiography and biomarker measurement. Forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) in percent of the predicted value and FEV1/FVC ratio were associated with echocardiographic measures of cardiac structure, systolic and diastolic func…

FEV1 and FVC predict all-cause mortality independent of cardiac function - Results from the population-based Gutenberg Health Study.

2017

Abstract Background Lung function has previously been related to increased mortality. Whether pulmonary impairment is associated with an increased mortality independent of cardiac dysfunction remains unclear. Methods In 15010 individuals from the general population (age range 35–74years, 51% men) in the Gutenberg Health Study we performed spirometry and transthoracic echocardiography. N-terminal pro-B-type natriuretic peptide (Nt-proBNP) and high-sensitive troponin I (hsTnI) were measured in all individuals. 1819 individuals with pulmonary diseases were excluded from further analysis. Results The median for forced expiratory volume in 1s (FEV1) was 94.2% and for forced vital capacity (FVC) …

The airway response to deep inspirations decreases with COPD severity and is associated with airway distensibility assessed by computed tomography.

2008

In patients with mild chronic obstructive pulmonary disease (COPD), the effect of deep inspirations (DIs) to reverse methacholine-induced bronchoconstriction is largely attenuated. In this study, we tested the hypothesis that the effectiveness of DI is reduced with increasing disease severity and that this is associated with a reduction in the ability of DI to distend the airways. Fifteen subjects [Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I–II: n = 7; GOLD stage III–IV: n = 8] underwent methacholine bronchoprovocation in the absence of DI, followed by DI. The effectiveness of DI was assessed by their ability to improve inspiratory vital capacity and forced expira…