Perspective Chapter: Viscoelastic Mechanical Equivalent Models

Today, we are living in a polymeric era where thousands of daily used products are manufactured from some polymeric materials with different tasks and under a wide range of ambient conditions, including time duration of loading and working condition temperature. This leads to focusing light spot on behavior of such specific materials and investigating the strain associated with the applied stress to understand both of creep and stress relaxation behavior of the loaded polymeric components. Hence, this chapter deals with the estimation of induced strain allied with the applied force on a polymeric material via establishing the so-called mechanical equivalent models starting from the simple elastic element (spring with a modulus of elasticity E), simple viscous element (damper or dashpot with fluid viscosity η), Maxwell model, Voigt model, modified Maxwell model, modified Voigt model, and Maxwell-Voigt model. The theoretical analysis was built on derivation of the prompted deformation, as a function of time in each of the employed models, as a result of the applied external load (force) and then by depending on Hook’s law transforming the gained expressions into stress (σ) and strain (ε) notation, followed by comparing the obtained equation with the general formula of the Hook’s law to find exact values of the constant and as coefficients of the stress and strain. Final theoretical analysis showed that Maxwell’s modified model was the best describing behavior of a loaded polymeric material to some extent followed by the other models

Développement d’applications de Télémédecine sur Smartphones

This thesis is a part of the general development framework for embedded applications in telemedicine. We started with a thorough study of the ECG signal through a full analysis of QRSTA (QRS-T-area) parameter of this signal. This study led to the development of our first application "DIAGNOSE ECG", embedded on a smartphone, for the determination of the QRSTA parameter, which is considered as an indicator of sudden death. Then, we studied the hemodynamic cardiorespiratory interactions in order to analyze their impact on sleep apnea and the condition of the drivers. In this context, we have contributed on the development of a multi-varied causal model, based on Granger's causality analysis between respiratory, hemodynamic and cardiac signals. Finally, we developed a new approach of analyzing physiological signal based on panel co-integration approach, allowing short- and long-term quantification using FM-OLS and DOLS estimators.Cette thèse s’inscrit dans le cadre général de développement des applications embarquées en télémédecine. Nous avons commencé par une étude approfondie du signal ECG à travers une analyse complète du paramètre QRSTA (QRS-T-area) de ce signal. Cette étude a conduit au développement de notre première application «DIAGNOSE ECG», embarquée sur un smartphone, pour la détermination du paramètre QRSTA considéré comme un indicateur de la mort subite. Ensuite, nous avons étudié les interactions cardiorespiratoires hémodynamiques afin d’analyser leurs impacts sur l’apnée du sommeil et sur l’état des conducteurs. Dans ce cadre, nous avons contribué par le développement d’un modèle causal multi-varié, basé sur la causalité de Granger entre les signaux respiratoires, hémodynamiques et cardiaques. Enfin, nous avons élaboré une nouvelle approche d’analyse des signaux physiologiques à base d’un modèle de co-intégration sur données panel, permettant la quantification à court et à long termes à l’aide des estimateurs FM-OLS et DOLS

The Direction of Information between Cardiorespiratory Hemodynamic Signals: Test Analysis using Granger Causality

cardiovascular diseases are the leading cause of worldwide mortality, each year more and more people die cause the cardiovascular disease comparatively to any other causes, the number of deaths because the cardiovascular disease is estimated at 17.3 million and represent 30% of the total global mortality, among these deaths, 7.3 million were caused by coronary heart disease and 6.2 million by AVC.Over 80% of deaths happen in countries with low and middle income and occur almost equally between men and women. By 2030, almost 23.3 million people will die from cardiovascular disease (mainly heart disease and AVC), according to projections, these diseases should remain the leading causes of death.This study analyzes the interactions that may exist between the three leads ECG, Hemodynamics signals, and the respiratory signals for the 187 patients taken from Montreal General Hospital / MF (Massachusetts General Hospital / Marquette Foundation) databases, using the Granger causality test for all patients. The results show significantly that there is a causality relationship between three leads ECG and other signals. Way of example, the results also indicate the existence of a unidirectional causality from ART, CVP, PAP, RESP, CO2 to ECG1 respectively 97.91%, 81.63%, 93.87%, 93.87%, 93.87% for all patients.The originality of this article is the number of variables selected for the study, unlike the majority of studies that are conducted only with two variable

Revealing the Dynamic Correlation between Cardiac and Respiratory Hemodynamic Signals Using Time-Dependent Panel Co- Integration Analysis

ABSTRACT: Panel Co-integration is one of the most popular methods to reveal and evaluate the influence and the interactions that may exist between long-term variables; Co-integration is used in different field and enjoying unprecedented popularity due reliability, clarity and robustness. In this article, we conducted an investigation using very powerful mathematical model to verify if a long-term relationship exists between Cardiorespiratory hemodynamic signals, the methodology we applied in this paper is mainly based on four basic parts, in first part we applied unit root tests to assess the stationarity of series, the second step is to apply the test of Co-integration model and quantify this long-term relationship. Finally we applied the Granger causality tests to the entire panel that consists of 186 patients taken from Montreal Hospital / General MF (Massachusetts General Hospital / Marquette Foundation) database. The results found in this study show the long-term interaction between the Cardiorespiratory hemodynamic signals, and reveals how the understanding of these interactions can help the doctors to understand the risks that may exist between these interactions. The originality of this article is the number of variables incorporated in our model study. Unlike the majority of studies that are conducted with only two variables, our study is specified by its multidimensionality. The main advantage of a multidimensional and multivariate model is to solve a multitude of problemsthatprevent doctors to treat the patients betterandis not the case for studies in two dimensions

Waveguide Amplifier for Extended Reach of WDM/FSO

In this chapter, EYDWA (erbium ytterbium doped waveguide amplifier) is characterized for wavelength division multiplexing (WDM) approach on free space optical (FSO) transmission systems with channels being spaced at 0.4 nm interval. Moreover, in this paper, was study different characterizations of EYDWA amplifier, which depend essentially on the opt-geometric parameters, such as concentrations of ions erbium, length of the waveguide and the effect of those parameters to optimize the performance of proposed system. Furthermore, the results reveal that the EYDWA booster (post-amplification) can improve the high performance remarkably under clear rain and the acceptable transmission can be carried out up to 26 km while it get reduced to 19.5 km by using pre-amplification

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)