Développement du questionnaire d’adaptation des étudiants à l’université (QAEU)

L’objectif de cette recherche est de présenter un outil d’évaluation de l’adaptation des étudiants à l’université, traduit d’une épreuve de langue anglaise : le S.A.C.Q. Les hypothèses relatives aux effets de la traduction et du contexte universitaire français visent à tester la validité de construction (structure du questionnaire, affectation des items aux différentes dimensions de l’adaptation). D’autres hypothèses portent sur la validité externe (relations avec les stratégies de coping et avec la variable sexe). Les données recueillies auprès d’un échantillon de 357 étudiants de première année de lettres et sciences humaines permettent de dégager six facettes de l’adaptation (sociale ; personnelle ; universitaire-performance, universitaire-application, universitaire-environnement ; attachement à l’institution). Un coping centré sur la tâche et décentré de l’émotion est favorable à une meilleure adaptation. Les hommes ont un niveau d’adaptation personnelle plus élevé que les femmes. Cette épreuve contribue à préciser la notion d’adaptation et offre un outil utile tant au niveau de la recherche que pour les professionnels de l’orientation.This study presents a tool to evaluate student adaptation to college that is a translation of the Student Adaptation to College Questionnaire (S.A.C.Q.). Hypotheses related to effects of translation and the French College context intend to test construct validity (structure of the questionnaire, items assignment to the different dimensions of adaptation). Other hypotheses are designed to test external validity of the scale (relationships to coping and the gender variable). The data collected from 357 freshmen in a Liberal Arts College lead us to structure the questionnaire along six dimensions (social, personal, academic performance, academic application, academic environment, and institutional attachment). Problem-focused coping and/or non-emotional coping mechanisms are predictive of good adjustment. Men score higher than women do on personal/emotional adjustment. This questionnaire represents a step towards a more accurate definition of adaptation and is a useful tool in terms of research and counselling

Managing irritable bowel syndrome: The impact of micro-physiotherapy

Contexte : Le syndrome du colon irritable (SCI) présente une pathologie complexe, une prévalence élevée et un impact important sur la qualité de vie des patients. Comme la thérapie conventionnelle n’apporte souvent que des résultats insatisfaisants, une approche plus holistique peut être souhaitable. L’étude actuelle a évalué l’effet de la microkinésithérapie sur la sévérité des symptômes du SCI. Méthodes : Dans cette étude en double aveugle, 61 patients récurrents du SCI ont été randomisés pour recevoir deux séances d’un traitement de microkinésithérapie ou d’un traitement simulé de microkinésithérapie. Les critères d’inclusion étaient la présence de ≥1 symptôme SCI de douleurs abdominales, constipation, diarrhée ou ballonnements. Les critères d’exclusion étaient une chirurgie intestinale majeure antérieure et la présence de maladies chroniques. L’âge moyen du patient était de 53,5 ± 15,3 ans. La microkinésithérapie consistait en un examen micro-palpatoire pour identifier les lésions ostéopathiques, suivi d’un micro-massage pour stimuler l’auto-guérison. Le groupe témoin a subi une procédure simulée. La présence et la gravité des symptômes ont été évaluées lors du suivi par un même gastro-entérologue au départ de l’étude et 1 mois après les séances. Résultats : Deux patients n’ont pas terminé l’étude. Il y a une différence significative entre le pourcentage de patients qui s’est amélioré après la première séance, à 74 % pour le groupe de microkinésithérapie et à 38 % pour le groupe placebo (p = 0,005). Après la deuxième séance, l’amélioration initiale a été maintenue dans les deux groupes, bien que sans plus de gains, et les différences entre les groupes d’étude sont demeurées significatives (p = 0,007). Conclusions : La microkinésithérapie améliore considérablement les symptômes du SCI et devrait être explorée plus avant pour une utilisation dans les soins de santé traditionnels.Background: Irritable bowel syndrome (IBS) has a complex pathology, high prevalence and large impact on patients’ quality of life. As conventional therapy may yield unsatisfactory results, a more holistic approach may be desirable. The current study assessed the effect of micro-physiotherapy on the severity of IBS symptoms. Methods: In a double-blind study, 61 recurrent IBS patients were randomised to two sessions of microphysiotherapy or sham micro-physiotherapy. Inclusion criteria were the presence of ≥1 IBS symptom from abdominal pain, constipation, diarrhoea or bloating. Exclusion criteria were previous major intestinal surgery and the presence of chronic diseases. The mean patient age was 53.5±15.3 years. Micro-physiotherapy consisted of micro-palpatory examination to identify osteopathic lesions, followed by micro-massage to stimulate self healing. The control group underwent a sham procedure. The presence and severity of symptoms was assessed at baseline and at 1-month follow-up by the same gastroenterologist. Results: Two patients did not complete the study. There was a significant difference in percentage of patients that improved after the first session, at 74 % for the micro-physiotherapy group and 38% for the sham group, respectively (p=0.005). After the second session, the initial improvement was maintained in both groups, although with no further gains, and the differences between the study groups remained significant (p=0.007). Conclusions: Micro-physiotherapy significantly improves IBS symptoms and should be further explored for use in mainstream healthcare

Impacts of the use of SIC semiconductors in actuations systems

Driven by customers’ demands to improve aircraft performance on one hand, while ensuring compliance to ACARE (Advisory Council for Aeronautics Research in Europe) environmental requirements for 2020 on the other, the aircraft industry has been pushing toward the concept of More Electric Aircraft (MEA) for the last ten years or so. One of the main challenges associated to the More Electric Aircraft is thus to increase drastically the power density of electrical power systems, such as electromechanical chains applied to actuation systems, without compromising on reliability. This paper explains the advantages of using Wide Bandgap (WBG) semiconductors made of Silicon Carbide (SiC) in the power converters that are used in an electromechanical chain as well as the associated drawbacks when it comes to EMI and partial discharge, which are mainly related to high dv/dt and overvoltage during commutation. It also shows the development of a generic electromechanical chain platform at the Institut de Recherche Technologique (IRT) Saint-Exupéry and all related research. This platform is being designed in order to test different technologies composing an electromechanical chain (SiC transistors, passive filters, cables, innovative motor) and to evaluate the impact of the use of such technologies

Trade-off between Losses and EMI Issues in Three-Phase SiC Inverters for Aircraft Applications

Power converters will only be effectively used in future aircrafts if they are compact, efficient and reliable. All these aspects can be improved by the use of disruptive technology such as the so-called Wide Bandgap (WBG) semiconductors made of Silicon Carbide (SiC) or Gallium Nitride (GaN). These components can switch much faster than their silicon counterpart, which can reduce converter losses and also decrease differential mode filter given the increase of switching frequency. However, such a fast commutation increases Electromagnetic Interference (EMI) issues in the converter and loads connected to it. This paper shows the approach developed at the French Institute of Technology (IRT) Saint-Exupery, in order to evaluate the trade-offs between losses and EMI issues of three-phase inverters used in future aircraft applications. Given the voltage DC bus of 540V, SiC MOSFETs are investigated and experimental results show the impact of these components on losses and EMI for different parameters

Unshielded Cable modeling for Conducted Emissions Issues in Electrical Power Drive Systems

In power electronics applications, high frequency models for cables are necessary to understand EMI issues in pulsewidth modulation drives. This paper shows the approach developed at the French Institute of Technology (IRT) Saint-Exupery, in order to take account of the frequency dependency of unshielded power cables per-unit-length parameters for EMC simulations. Fast, predictive models are compared to different shapes numerical models. The method was applied to unshielded two and three wires cables. Finally, common mode (CM) emissions modeling is proposed to predict the CM noise currents, which are the most disturbing in any variable-speed drive systems. The modeling principle is to consider the complete CM circuit as a chain of quadripolar matrices

Overvoltage at motor terminals in SiC-based PWM drives

Key points in the development of More Electrical Aircraft (MEA) are currently DC power distribution in higher voltage levels (540 V) and the use of disruptive technology such as Wide BandGap (WBG) semiconductors in power inverters. Using WBG components (SiC and GaN) increases the power converter mass density. However, fast switching of WBG components (tens of kV/s) induces voltage transient overshoots due to parasitic elements within the inverter. In addition, propagation and reflection phenomena along the harness connected to this inverter, even for small lengths, cause a significant voltage overshoot across the loads. Such overvoltage in Adjustable Speed Drives (ASD: association of inverter, harness and motor) supplied by the new HVDC 540 V aeronautical network could be fatal for the Electrical Insulation System (EIS). This paper proposes a fast and accurate modeling methodology to predict transient overvoltage; it allows us to analyze the impact of SiC inverter technology on overvoltage at motor terminals

Advanced analysis of transient overvoltage in electromechanical chain fed by SiC inverter

Key areas in the development of More Electrical Aircraft (MEA) are, currently, DC power distribution in higher voltage levels and the use of disruptive technology such as Wide BandGap (WBG) semiconductor. Using WBG components (SiC and GaN) increases the power converter mass density. However, fast switching of WBG components (tens of kV/µs) induces voltage transient overshoots due to parasitic coupling within the inverter. In addition, propagation and reflection phenomena along the harness, even for small lengths, cause voltage overshoots across the loads. Such overvoltage in an electromechanical chain (association of inverter, harness and motor) supplied by the new HVDC 540V aeronautical network could be fatal for the Electrical Insulation System (EIS). This paper proposes an accurate and fast model to predict overvoltage along a harness; it allows to analyze the impact of SiC inverter output voltage waveforms

Investigations on Partial Discharges risk in aeronautical rotating machine fed by HVDC 540Vdc network

The voltage level aboard new aircraft generations has grown from 115V AC to 230V AC . This has given rise to a new HVDC +/- 270V instead of +270V. The Adjustable Speed Drives (ASD) aboard more electrical aircraft are currently fed by fast switching PWM IGBT converters which rise time and fall time are higher than 50ns. To improve the converters power density, the very fast Wide Bandgap semiconductor technologies (Silicon Carbide) are currently under evaluation; their switching rise time and fall time could be lower than 20ns. This paper, by using industrial ASD fed by 540Vdc, initially addresses an experimental investigations analysis of motor overvoltages according to: inverters technologies (IGBT and SiC), harness length and harness shielding. Then, investigations on the Partial Discharges Inception Voltage (PDIV) are carried out on primary components of Electrical Insulation System (EIS) type 1 at atmospheric and reduced pressures, according to several parameters: magnet wire (MW) diameter, MW grade, polyimide insulating paper thickness. The paper concludes with a discussion of the different results and thoughts about overvoltages and partial discharges challenges

A strategy for human factors/ergonomics: developing the discipline and profession

Human factors/ergonomics (HFE) has great potential to contribute to the design of all kinds of systems with people (work systems, product/service systems), but faces challenges in the readiness of its market and in the supply of high-quality applications. HFE has a unique combination of three fundamental characteristics: (1) it takes a systems approach (2) it is design driven and (3) it focuses on two closely related outcomes: performance and well-being. In order to contribute to future system design, HFE must demonstrate its value more successfully to the main stakeholders of system design. HFE already has a strong value proposition (mainly well-being) and interactivity with the stakeholder group of 'system actors' (employees and product/service users). However, the value proposition (mainly performance) and relationships with the stakeholder groups of 'system experts' (experts from technical and social sciences involved in system design), and 'system decision makers' (managers and other decision makers involved in system design, purchase, implementation and use), who have a strong power to influence system design, need to be developed. Therefore, the first main strategic direction is to strengthen the demand for high-quality HFE by increasing awareness among powerful stakeholders of the value of high-quality HFE by communicating with stakeholders, by building partnerships and by educating stakeholders. The second main strategic direction is to strengthen the application of high-quality HFE by promoting the education of HFE specialists, by ensuring high-quality standards of HFE applications and HFE specialists, and by promoting HFE research excellence at universities and other organisations. This strategy requires cooperation between the HFE community at large, consisting of the International Ergonomics Association (IEA), local (national and regional) HFE societies, and HFE specialists. We propose a joint world-wide HFE development plan, in which the IEA takes a leadership role. Practitioner Summary: Human factors/ergonomics (HFE) has much to offer by addressing major business and societal challenges regarding work and product/ service systems. HFE potential, however, is underexploited. This paper presents a strategy for the HFE community to strengthen demand and application of *Corresponding author. Email: [email protected] high-quality HFE, emphasising its key elements: systems approach, design driven, and performance and well-being goals