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  • Public defence: 2020-02-06 10:00 C208
    Agic, Adnan
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Edge Geometry Effects on Entry Phase by Forces and Vibrations2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Intermittent machining is in general strongly related to the large impacts in the entry phase and related vibrations. The influence of the impact forces and vibrations on the cutting process is dependent on workpiece material, structural properties of the tool-workpiece system, cutting edge geometries and cutting parameters. Cutting forces adopt generally a periodic behaviour that gives rise to forced vibrations. In addition, self-induced vibrations may arise because of lowrigidity and insufficient damping in the tool-workpiece system at specific cutting parameters. The ability of the cutting tool to carry the loads during the entry phase and minimize the vibrations is often the key parameter for an effective machining operation.This research work is based on the experiments, analytical studies and modelling. It was carried out through six main studies beginning with a force build-up analysis of the cutting edge entry into the workpiece in intermittent turning. This was followed by a second study, concentrated on modelling of the entry phase which has partly been explored through experiments and theory developed in the first study.

    The third part was focused on the influence of the radial depth of cut upon the entry of the cutting edge into the workpiece in a face milling application. The methodology for the identification of unfavourable radial depth of cut is also addressed herein. Next, effects of the cutting edge on the vibrations in an end milling application were investigated. This study was related to a contouring operation with the maximum chip thickness in the entry phase when machining steel, ISO P material.

    The results of this work provide some general recommendations when milling this type of workpiece material. After that, the focus was set on the dynamic cutting forces in milling. The force developments over a tooth engagement in milling showed to be strongly dependent on the cutting edge geometry. A significant difference between highly positive versus highly negative geometry was found.

    The implication of this phenomena on the stress state in the cutting edge and some practical issues were analysed. Finally, the role of the helix angle on the dynamic response of a workpiece was investigated. The modelling technique using force simulation and computation of the dynamic response by means of modal analysis was presented. Extensive experimental work was conducted to compare the modelling and experimentally obtained results. The modelling results showed a similar trend as the experimental results. The influence of helix angle on the cutting forces and the dynamic response was explained in detail.The research conducted in this work contributes to the deeper understanding of the influence of the cutting edge geometry and the cutting parameters on the force build up process during the entry phase. The presented studies investigate the force magnitudes, force rates and dynamic behaviour of the tools and workpieces when machining at the challenging entry conditions. The methodologies applied are focused on the physical quantities as forces and vibrations rather than the experimental studies that evaluate tool life. The methods and results of the research work are of great interest for the design of the cutting tools and optimization of the cutting processes.

  • Zouini, Btissame
    et al.
    Abdelmalek Essaadi University, Department of Biology, Faculty of Sciences, Tetouan, Morocco.
    Sfendla, Anis
    Higher Institute of Nursing Professions and Health Techniques, Errachidia, Morocco.
    Hedman Ahlström, Britt
    University West, Department of Health Sciences, Section for health promotion and care sciences.
    Senhaji, Meftaha
    Abdelmalek Essaadi University, Faculty of Sciences, Tetouan, Morocco.
    Kerekes, Nora
    University West, Department of Health Sciences, Section for health promotion and care sciences.
    Mental health profile and its relation with parental alcohol use problems and/or the experience of abuse in a sample of Moroccan high school students: An explorative study2019In: Annals of General Psychiatry, ISSN 1744-859X, E-ISSN 1744-859X, Vol. 18, no 1, article id 27Article in journal (Refereed)
    Abstract [en]

    Background: Studies on mental health are scarce from Arab countries, especially studies focusing on adolescents. In addition to the neurobiological and physiological changes that occur during adolescent development, psychological, societal and cultural influences have strong effects on adolescents’ behavior and on their somatic and mental health. The present study aimed (1) to describe the mental health profile, operationalized as psychological distress, of a sample of Moroccan adolescents, and (2) to investigate how specific psychosocial factors (parental alcohol use problems and the experience of physical and/or psychological abuse) may affect adolescents’ mental health. Methods: The sample included 375 adolescents from conveniently selected classes of four high schools in the city of Tetouan in Morocco. The participants responded to an anonymous survey containing, beside other inventories, the Brief Symptom Inventory (BSI) and identified those reporting parental alcohol use problems and/or the previous experience of abuse. The sample characteristics were defined using descriptive statistics. The effects of the defined psychosocial factors were identified using the Kruskal-Wallis test, followed by the post hoc Fisher’s least significant difference test. Results: The most common problems found in high school students from an urban region of Morocco were memory problems, concentration difficulties, restlessness, fear, nervosity and feelings of inadequacy during interpersonal interactions. The female students reported significantly higher psychological distress levels when compared to the male students (p < 0.001). The adolescents reporting parental alcohol use problems and the experience of physical/psychological abuse showed significantly higher levels of psychological distress (p = 0.02), especially symptoms of somatization (p < 0.001), hostility (p = 0.005) and anxiety (p = 0.01), than those not reporting any of these psychosocial factors. Conclusion: The mental health profile of female adolescents from an urban area of Morocco is worse than that of their male fellow students. Adolescents reporting parental alcohol use problems and/or the experience of physical/psychological abuse need synchronized support from social- A nd healthcare services. © 2019 The Author(s).

  • Dåderman, Anna Maria
    et al.
    University West, Department of Social and Behavioural Studies, Division of Psychology, Pedagogy and Sociology. Karolinska Institutet.
    Hallberg, Angela
    University West, Department of Social and Behavioural Studies, Division of Psychology, Pedagogy and Sociology.
    Skog, Sandra
    University West, Department of Social and Behavioural Studies, Division of Psychology, Pedagogy and Sociology.
    Kajonius, Petri
    University West, Department of Social and Behavioural Studies, Division of Psychology, Pedagogy and Sociology.
    Emotional Leadership in Relation to Task Performance, Work Engagement, and Perceived Stress2019In: Working for the greater good: Inspiring people, designing jobs and leading organizations for a more inclusive society / [ed] Prof. Franco Fraccaroli, Turin, 2019Conference paper (Refereed)
    Abstract [en]

    Purpose: To describe and explore emotional leadership meta-resources based on traits (self-esteem, emotional intelligence, leadership intelligence, empathy, Big Six, narcissism) and coping resources (e.g. cognitive), using Hobfoll’s motivational Conservation of Resources (COR). Our hypothesis was that leadership resources would be positively related to work engagement and negatively to perceived stress.

    Methodology: Participants (N = 344) were leaders aged between 23 and 65 years (M = 49, SD = 8.6; 58% women) who completed an online questionnaire including measures of common traits and coping resources. Work engagement was measured by Utrecht Work Engagement Scale (UWES-9; Schaufeli & Bakker, 2004), and stress by Perceived Stress Scale (PSS-10; Cohen & Williamson, 1988). We used an exploratory factor analysis approach to describe and structure our data, and structural equation modelling (SEM) to test whether an emotional leadership meta-resource factor would be positively related to work engagement and negatively to perceived stress.

    Results: The investigated traits and resources could be described along four broad emotional leadership resource factors: (1) Externalizing; (2) Moral goodness; (3) Destrudo; (4) Rational mastery. As expected, the emotional leadership meta-resource factor showed a strong convergence (~.80) with both work engagement (positively) and perceived stress (negatively). 

    Research/Practical Implications: The results imply that organizations may strengthen work engagement and reduce stress by recruiting leaders possessing valuable emotional leadership resources.

    Originality/Value: Our study is the first to describe emotional leadership resources based on traits linked with work engagement and perceived stress in a novel fashion (meta-traits, based on structural trait analysis).

  • Dåderman, Anna Maria
    et al.
    University West, Department of Social and Behavioural Studies, Division of Psychology, Pedagogy and Sociology.
    Hjalmarsson, Annica
    University West, Department of Social and Behavioural Studies, Division of Psychology, Pedagogy and Sociology.
    Relationship between emotional intelligence, personality and work performance: A cross-sectional study2019Conference paper (Refereed)
    Abstract [en]

    The background of this study is the observation that people with high emotional intelligence (EI) perform well at work. The aim of this study was to further validate the Trait Emotional Intelligence Questionnaire Short Form (TEIQue-SF) by (1) investigating its relationships with the Mini International Personality Item Pool-6 Inventory (Mini-IPIP6), the Short Dark Triad Assessment (SD3), and the Individual Work Performance Questionnaire (IWPQ), (2) identifying which personality traits best explain variations in trait EI, and (3) investigating whether trait EI can predict variations in each dimension (Task Performance, Contextual Performance, and Counterproductive Work Behavior, CWB) of self-perceived work performance. A cross-sectional study was done with 228 Swedish participants (M = 34 years, SD = 12.6, range 16-71 years, 66% women) with an average work experience of 14 years (SD = 11.5). One expected result was that all dimensions of trait EI correlated negatively with Neuroticism and Machiavellianism, and positively with Extraversion, Agreeableness, Conscientiousness, Openness to Experience, and Narcissism. Self-control and Sociability had, however, almost zero correlation with Machiavellianism. A positive correlation was found between all dimensions of EI and Task Performance and Contextual Performance. Standard regression analyses showed that 26% to 46% of the variation in the different dimensions of EI was explained by the “Big Six” personality traits. Hierarchical multiple regression analyses indicated that trait EI accounted for a significant proportion of the variation in Contextual Performance that was not explained by any of the “Big Six” personality traits, and that trait EI did not explain any variation in CWB above Neuroticism and Honesty-Humility. In addition, trait EI explained an additional 6% of the variation in Task Performance when controlling for gender, age, Neuroticism and Conscientiousness. It is concluded that the Swedish version of the TEIQue-SF has shown reasonable theoretically and empirically grounded relationships with relevant variables for the workplace.