Caracterización, cuantificación y análisis de la distribución espacial de microplásticos en el golfo de Cádiz

La contaminación de los sistemas marinos por microplásticos (MPs) está siendo estudiada a escala global en los mares y océanos. Esto es debido a la gran abundancia y ubicuidad que este tipo de polución presenta. En esta Tesis de Máster se ha evaluado la presencia de MPs en las aguas subsuperficiales del golfo de Cádiz, en seis radiales distintas, desde el cabo de Trafalgar hasta la desembocadura del río Guadiana, en el extremo suroccidental de la Zona Económica Exclusiva de las aguas españolas. A través de la campaña número 42 de la serie STOCA se filtraron un total de 46,307 L de agua de mar a través de una malla metálica con luz de 45 μm, distribuidos en 16 muestras. Tras la obtención del material particulado se realizó una digestión alcalina-oxidante (KOH-H2O2) para degradar la materia presente en estas. De manera general, se encontraron MPs en todas las estaciones estudiadas de las diferentes radiales, con una concentración media de 2 MPs·m-3. Las fibras fueron el tipo de ítem más abundante (70.2 %), seguido de las partículas tipo film (16.4 %) y los fragmentos (13.4 %). Alrededor del 70 % de los ítems encontrados se sometieron a una caracterización química a través del análisis de micro-espectroscopía infrarroja por Transformada de Fourier (μ-FTIR). El análisis de similitudes (ANOSIM) no mostró variación de la concentración de microplásticos entre las diferentes radiales a lo largo de la costa, pero si encontró un patrón de disminución de estas al aumentar la distancia desde costa. El análisis del modelo lineal múltiple basado en las distancias (DISTLM) realizado entre las variables de los MPs (concentración, tamaño, tipo, composición polimérica) y las variables oceanográficas (temperatura, salinidad, conductividad, oxígeno disuelto, fluorescencia y turbidez) no mostró relaciones significativas. Los resultados sugieren que las fuentes de contaminación de origen terrestre dominan los aportes de MPs en la zona de estudio

Fractional exhaled nitric oxide and eosinophil count in induced sputum to guide the management of children with asthma: a cost-utility analysis

Introduction: Previous evidence has shown that fractional exhaled nitric oxide (FeNO) and eosinophil count in induced sputum (EO) are cost-effective relative to standard of care in guiding the management of children with persistent asthma. There is some doubt as if there are differences between these two biomarkers in terms of costs and benefits. Clarifying this doubt would allow prioritization of the design of clinical practice guidelines. The study aimed to compare in terms of costs and benefits these biomarkers in patients with asthma between 4 and 18 years of age. Methods: A Markov model was used to estimate the cost-utility of asthma management using FeNO and EO in patients between 4 and 18 years of age. Transition probabilities, cost and utilities were estimated from previously published local studies, while relative risks were obtained from the systematic review of published randomized clinical trials. The analysis was carried out from a societal perspective. Results: The expected annual cost per patient with EO was USD1376 (CI 95% USD1376–USD1377) and for FeNO was USD1934 (CI 95% USD1333–USD1334), with a difference of USD42.3 between these strategies. The Quality-adjusted life years (QALYs) per person estimated with EO was 0.95 (CI 95% 0.951–0.952) and for FeNO was 0.94 (CI 95% 0.930–0.940), with a difference of 0.01 between these strategies. The NMB with EO was USD4902 (CI 95% 4900–4904) and for FeNO was USD4841 (CI 95% 4839–4843). The incremental cost-effectiveness ratio of EO was $3566 per QALY gained regarding FeNO. Conclusion: Our study demonstrates that induced sputum-guided management is a strategy cost-effective over FeNO and standard asthma management in Colombia. This evidence should encourage the adoption of any of these techniques to objectively guide the management of children with asthma in routine clinical practice in low-resource settings

Numerical analysis of high velocity impacts on unidirectional laminates

In this work a numerical methodology to predict the behavior of composite unidirectional laminates under high velocity impact is developed. In order to validate the model, experimental results of high velocity impacts of steel sphere against laminate coupons, were accomplished. The residual velocity in case of penetration and the damaged area in the panel are the variables chosen to validate the results obtained in the numerical methodology proposed. Finally an analysis of the influence of the projectile geometry is accomplished. (C) 2013 Elsevier Ltd. All rights reserved

Analysis of high velocity impacts of steel cylinders on thin carbon/epoxy woven laminates

In this work a numerical model was developed to predict the behavior of thin woven laminates under high velocity impacts. The material model, implemented in a user subroutine to be used with a commercial FE code, takes into account different failure mechanisms. The inter-lamina failure prediction is achieved by means of the use of cohesive elements. Finally, in order to validate the model, experimental tests were accomplished in a wide range of velocities from 100 to 400 m/s. Residual velocity of the projectile and damaged area of the laminates are compared with the numerical results. Once the model is validated, a further investigation has been made in order to analyze the influence of projectile slenderness on the laminate response.This research was done with the ¯nancial support of the Spanish Ministry of Education under Project reference DPI2010-15123 and of the Region of Madrid and University Carlos III of Madrid under Project reference CCG10-UC3M/DPI-4694

On the influence of filling level in CFRP aircraft fuel tank subjected to high velocity impacts

In this work, the process of impact that takes place in a partially filled tank is analyzed, performing a numerical simulation, in order to understand the response of the composite laminated structure. The commercial finite-element code LS-DYNA v.R7 has been used to simulate an Hydrodynamic RAM event created by a steel spherical projectile impacting a partially water-filled woven CFRP square tube using two different approaches (MM-ALE and SPH). The intralaminar and interlaminar damage have been taken into account implementing an user subroutine and by means of a cohesive interaction, respectively. Once the numerical model is validated using available experimental data, the effect of the filling level in the failure of the tank is analyzed in detail taking advantage of the information provided by the numerical model. (C) 2013 Elsevier Ltd. All rights reserved.This research was done with the financial support of the Spanish Ministry of Education under Project reference DPI2010-15123 and of the Region of Madrid and University Carlos III of Madrid under Project reference CCG10-UC3M/DPI-4694

Experimental analysis of normal and oblique high velocity impacts on carbon/epoxy tape laminates

In this work, the effect of high velocity impacts on carbon/epoxy tape quasi-isotropic laminates is studied. Experimental test were carried out at two different impact angles and in a wide range of velocities (from 80 to 490 m/s). Both parameters, the residual velocity and the damaged area, are used to evaluate the effect of the kinetic energy of the projectile on the laminate response. In addition it has been proposed a simplified analytical model which allows to identify the different energy absorbtion mechanisms and predict the residual velocity of the projectile. Finally the energy absorbed by the laminate during the impact is studied.This research was done with the financial support of the Spanish Ministry of Ed- ucation under Project reference DPI2010-15123 and of the Region of Madrid and University Carlos III of Madrid under Project reference CCG10-UC3M/DPI-4694

Analysis of Ice Impact Process at High Velocity

In this work the high velocity impact of ice spheres is analysed. An experimental methodology has been developed in order to launch, at high velocity, ice spheres of different diameters against a load cell to measure the force induced during the impact. An analysis of the influence of the ice mass on the impact force is accomplished using the contact force which was calculated by means of an inverse problem technique. Finally a study of the impact phenomenon has been performed using the videos obtained with a high speed camera.This research was done with the financial support of the Spanish Ministry of Education under Project reference DPI2013-41094-R

Numerical analysis of CFRP fluid-filled tubes subjected to high-velocity impact

In recent years, vulnerability against high-velocity impact loads has become an increasingly critical issue in the design of composite aerospace structures. The effects of Hydrodynamic Ram (HRAM), a phenomenon that occurs when a high-energy object penetrates a fluid-filled container, are of particular concern in the design of wing fuel tanks for aircraft because it has been identified as one of the important factors in aircraft vulnerability. The projectile transfers its momentum and kinetic energy through the fluid to the surrounding structure, increasing the risk of catastrophic failure. In the present paper, the commercial finite-element code ABAQUS/Explicit has been used to simulate an HRAM event due to the impact of a steel spherical projectile into a water-filled woven CFRP square tube. In order to simulate the fluid-structure interaction, the Coupled Eulerian Lagrangian (CEL) approach is used. Experimental tests which indicate the pressure at different points of the fluid, strains of the walls and cavity evolution for different impact velocities are compared with the numerical results in order to assess the validity and accuracy of CEL technique in reproducing such a complex phenomenon. Also, several numerical impacts at different initial projectile velocities are performed to study its influence in the HRAM phenomenon.This research was done with the fianancial support of the Spanish Ministry of Education under Project reference DPI2010-15123 and of the Region of Madrid and University Carlos III of Madrid under Project reference CCG10-UC3M/DPI-4694. The authors would like also to acknowledge the Center for the Development of Industrial Technology (CDTI) of Spain and to the company AERNNOVA Aerospace for the financial support for this research. We wish to express sincere gratitude to Mr. S. Puerta for his valuable help during the experimental testing

Experimental study of the impactor mass effect on the low velocity impact of carbon/epoxy woven laminates

In this work, the analysis of the impactor mass effect on the behaviour of carbon/epoxy woven laminates under low velocity impact is carried out. To this end experimental test were performed by means of a drop weigh tower in a range of energies varying from 10 to 110 J, and using three different impactor masses. Two different laminate thicknesses were considered in order to take into account its possible influence. An analysis of the impact tests is performed using the Composite Structure Impact Performance Assessment Program, in order to observe the influence of impactor mass. Once impacted, the laminates were inspected by means of a C-Scan (to quantify the delamination extension) and a phased array ultrasonic system (to analyse the failure through the thickness); this non-destructive analysis will determine the influence of the impactor mass on the laminate failure. (C) 2015 Elsevier Ltd. All rights reserved.This research was done with the financial support of the Spanish Ministry of Economy and Competitiveness under Project reference DPI2013 41094 R

Experimental analysis of ice sphere impacts on unidirectional carbon/epoxy laminates

This work analyses the behaviour of carbon/epoxy unidirectional laminates subjected to high velocity impacts of ice spheres. To this end, ice projec- tiles were launched against composite laminates in a wide range of velocities (50 -250 m/s). Two different ice diameters (40 and 50 mm) and two laminate thicknesses (4 and 6 mm) were considered. The internal damage was measured using both destructive and non-destructive techniques, which allow an accurate quanti cation of the delaminated area. Finally the in uence of the different parameters considered on the damage of the laminate is analysed by means of a dimensionless variable.This research was done with the financial support of the Spanish Ministry of Economy and Competitiveness under Project reference DPI2013-41094-R