This work aims to develop and implement a linear elastic grain-level micromechanical model based on the discrete element method using bonded contacts and an improved fracture criteria to capture both intergranular and transgranular microcrack initiation and evolution in polycrystalline ceramics materials. Gaining a better understanding of the underlying mechanics and micromechanics of the fracture process of brittle polycrystalline materials will aid in high performance material design. Continuum mechanics approaches cannot accurately simulate the crack propagation during fracture due to the discontinuous nature of the problem. In this work we distinguish between predominately intergranular failure (along the grain boundaries) versus predominately transgranular failure (across the grains) based on grain orientation and microstructural parameters to describe the contact interfaces and present the first approach at fracturing discrete elements. Specifically, the influence of grain boundary strength and stiffness on the fracture behavior of an idealized ceramic material is studied under three different loading conditions: uniaxial compression, brazilian, and four-point bending. Digital representations of the sample microstructures for the test cases are composed of hexagonal, prismatic, honeycomb-packed grains represented by rigid, discrete elements. The principle of virtual work is used to develop a microscale fracture criteria for brittle polycrystalline materials for tensile, shear, torsional and rolling modes of intergranular motion. The interactions between discrete elements within each grain are governed by traction displacement relationships.

The Covid-19 global pandemic has challenged traditional models of leadership and change management. In a few months, organisations were forced to transform into working virtually, either partially or wholly. In this context, leadership practices have been crucial to the survival of organisations and their capability to manage that change with minimum interruption and constant productivity. Leadership is a complex social and organisational phenomenon, and this study takes on the novel Leadership-as-practice perspective that understands leadership as an emerging and unfolding process through daily experience and offers an alternative to restrictive traditional competency models. In the era of communications technology, traditional leadership models, remote working, and change management have already been intensively studied. However, little research in the IT management area combines those three topics in the context of a crisis, and leaders were left without clear and researchbased references to guide their efforts during this pandemic. Thus, this study seeks to close that research gap and identify which practices leaders used to strategically and effectively leverage virtual teams to sustain productivity and keep business operational during a global crisis. This study was conducted with a case study research strategy, and data were collected from eleven semistructured interviews with leaders from different levels and organisations across Europe and North America. The chosen data analysis method was grounded theory to ensure findings were grounded in data, along with thematic analysis and constant comparative analysis. Results revealed three categories of practices were central to managing the change to virtual collaboration during the Covid-19 pandemic: Intentional and frequent communications, adaptability, and people-centric focus. Previous research indicates these were not common to other crises, and their absence might have led to destructive leadership behaviours during the pandemic context. These results are coherent with the recent rise of the transformational leadership current and its emphasis on human values in business contexts. From a research perspective, this study fills the gap in extant research and contributes to the growing body of literature using the Leadership-as-practice perspective. From a business perspective, these practices offer leaders a simple framework to guide their change efforts and might imply a need to rethink the manager-team member relationship and responsibilities. Similarly, they might point towards a greater responsibility for organisations to address remote working and secure employee well-being during crises.

Background: The traditionally homogeneous work environment, historically associated with physical locations such as offices and buildings, has undergone significant changes in recent years. This change has been driven by technological innovation, cultural development and external challenges, an accelerator in this process was the global spread of covid-19, which radicalized the traditional way of working. Purpose: The purpose of this study is to create a deeper understanding of how leadership has been affected in step with work environment changes. A delimitation has been made towards an explicit work environment, the hybrid environment.  Methodology: Through a combination of literature review and qualitative data collection methods such as interviews, has this study investigated how leadership practices have changed and adapted to the hybrid work environment in symbiosis with what challenges and adaptations, have developed.  Result: The results show that leaders must now be more empathetic, communicative, and consultative than before. They also need to possess a combination of emotional and technical skills to effectively navigate the complexity that the combined work environment entails. In addition, the importance of being able to manage and understand team dynamics and the emotional needs of individuals has become more prominent. Conclusion: Today's leaders, which are operating in hybrid work environments, face the challenging task of balancing technical competence along with human dynamics. To be effective, these leaders must be agile, forward-thinking and tech savvy. Success lies in their ability to combine innovative methods with a deep understanding of human interaction, which is critical to their effectiveness in this rapidly changing work environment.

Enabled by advanced information technologies, the distributed work environment has become a choice of organizations. When employees and supervisors work in geographically separate locations, management challenges emerge. Performance improvement may become an issue. Performance may be improved by identifying, studying, and improving factors that affect work performance. Two factors–feedback and goal setting–were chosen for this study because of the strong evidence of the effects of these components. Positive effects of feedback and goal setting are commonly accepted in the literature concerning the traditional work environment. This study focused only on knowledge work because most work in the distributed work environment may be knowledge work. The purpose of this study was to investigate the effects of feedback and goal setting on knowledge work performance in the distributed work environment. A laboratory experiment was conducted using 36 student subjects. The experimental design was a 3 X 2 factorial design consisting of three levels of feedback (i.e., no feedback, task feedback, and task feedback with comparisons with others) and two levels of goal setting (i.e., no goal setting and goal setting). Subjects were randomly assigned to various combinations of these two variables. The evidence did not outright support the claim that feedback and goal setting improve task performance; task performance of the subjects was improved only under certain conditions. Task feedback did not improve task performance because of its added pressure, especially in the presence of goals. Task performance was higher for the subjects who received both task feedback and information about others’ performance than for the subjects who received task feedback only. Overall, feedback was not found to improve task performance. The study did not support the hypothesis that specific and difficult goals improve task performance. The added pressure of having difficult goals was found to have demotivating effects. The notion that the co-presence of feedback and goals is necessary to improve task performance was not supported because of the combined pressure that both components created. The subjects who had feedback and/or goals did not perform better than those who had neither feedback nor goals. / Ph. D.

Globalisation, technological advancements and changing social needs result in virtual work arrangements becoming more prominent. Virtual work is conducted away from the traditional office setting and usually occurs in employees’ personal home environments. Virtual work has been called virtualling in this study, and virtual employees are referred to as virtuallers. A phenomenological orientation was adopted in studying completely virtual workers in a completely virtual context; sourcing of participants and data collection were also conducted completely virtually. This study presented new ways of conducting research in the modern, virtual world of work. An autoethnography was included, as the researcher is also a virtualler and insider of virtualling. Four key case studies are presented to provide a holistic picture of virtualling and virtuallers. Thematic results indicate key influencing factors that originate from virtualling, as well as factors and mindset requirements that pertain to the virtualler personally. It was further found and proposed that the resulting virtual environment changes virtuallers’ ways of doing things and viewing the world, hence results in changes in their lifestyle and career identity. The abstract psychological structure as it resulted from the thread of meanings was presented as virtualness. Authentic psychological identification with virtualling and adopting a boundarylessness employability mindset oriented towards psychological success are highlighted as key requirements in order to experience virtualness. / Industrial and Organisational Psychology / MCOM (Industrial and Organisational Psychology)

Globalisation, technological advancements and changing social needs result in virtual work arrangements becoming more prominent. Virtual work is conducted away from the traditional office setting and usually occurs in employees’ personal home environments. Virtual work has been called virtualling in this study, and virtual employees are referred to as virtuallers. A phenomenological orientation was adopted in studying completely virtual workers in a completely virtual context; sourcing of participants and data collection were also conducted completely virtually. This study presented new ways of conducting research in the modern, virtual world of work. An autoethnography was included, as the researcher is also a virtualler and insider of virtualling. Four key case studies are presented to provide a holistic picture of virtualling and virtuallers. Thematic results indicate key influencing factors that originate from virtualling, as well as factors and mindset requirements that pertain to the virtualler personally. It was further found and proposed that the resulting virtual environment changes virtuallers’ ways of doing things and viewing the world, hence results in changes in their lifestyle and career identity. The abstract psychological structure as it resulted from the thread of meanings was presented as virtualness. Authentic psychological identification with virtualling and adopting a boundarylessness employability mindset oriented towards psychological success are highlighted as key requirements in order to experience virtualness. / Industrial and Organisational Psychology / M.Comm. (Industrial and Organisational Psychology)

No description available.

O objetivo deste trabalho é o desenvolvimento de um pós-processador para um software baseado no método dos elementos finitos destinado a problemas de eletromagnetismo. Três métodos de determinação de torque de origem eletromagnética são abordados e comparados do ponto de vista da precisão e implementação, quais sejam: variação da energia magnética, integração do tensor de Maxwell e princípio do trabalho virtual (derivada do jacobiano local). Dois métodos são propostos para a determinação de reatâncias de eixo direto e em quadratura de máquinas síncronas. A metodologia é aplicada na análise de um motor síncrono de relutância de 15 hp, 380v, 4 pólos, cujos resultados são apresentados no capítulo IV. / The aim of this work is to develop a post-processor for use with an electromagnetism-oriented software based upon the Finite Elements Method. Three methods for determining electromagnetic torque are presented and compared in terms of precision and implementation: (i) Variation of Magnetic Energy, (ii) Maxwell Stress Method and (iii) Virtual-work Principle (Local Jacobian Derivative). Two methods for calculating direct-axis and quadrature-axis reactances of synchronous machines are proposed. The methodology is applied in the analysis of a 15 HP, 380 v, 4-pole reluctance synchronous motor and the results are presented in Chapter IV.

O objetivo deste trabalho é o desenvolvimento de um pós-processador para um software baseado no método dos elementos finitos destinado a problemas de eletromagnetismo. Três métodos de determinação de torque de origem eletromagnética são abordados e comparados do ponto de vista da precisão e implementação, quais sejam: variação da energia magnética, integração do tensor de Maxwell e princípio do trabalho virtual (derivada do jacobiano local). Dois métodos são propostos para a determinação de reatâncias de eixo direto e em quadratura de máquinas síncronas. A metodologia é aplicada na análise de um motor síncrono de relutância de 15 hp, 380v, 4 pólos, cujos resultados são apresentados no capítulo IV. / The aim of this work is to develop a post-processor for use with an electromagnetism-oriented software based upon the Finite Elements Method. Three methods for determining electromagnetic torque are presented and compared in terms of precision and implementation: (i) Variation of Magnetic Energy, (ii) Maxwell Stress Method and (iii) Virtual-work Principle (Local Jacobian Derivative). Two methods for calculating direct-axis and quadrature-axis reactances of synchronous machines are proposed. The methodology is applied in the analysis of a 15 HP, 380 v, 4-pole reluctance synchronous motor and the results are presented in Chapter IV.

Virtual Reality (VR) video is emerging as a new art form. Viewing VR video requires wearing the VR headset to fully experience the immersive surrounding of the content. However, the novel viewing experience of VR video creates new challenges and requirements for conventional video authoring tools, which were designed mainly for working with normal video on a desktop display. Designing effective authoring tools for VR video requires intuitive video interfaces specific to VR. This dissertation develops new workflows and systems that enable filmmakers to create and improve VR video while fully immersed in a VR headset. We introduce a series of authoring tools that enables filmmakers to work with video in VR: 1) Vremiere, an in-headset video editing application that enables editors to edit VR video entirely in the headset, 2) CollaVR, a networked system that enables multiple users to collaborate and review video together in VR, and 3) a set of techniques to assist filmmakers in managing and accessing interfaces in stereoscopic VR video without suffering depth conflicts. The design of these applications is grounded in existing practices and principles learned in interviews with VR professionals. A series of studies is conducted to evaluate these systems, which demonstrate the potential of in-headset video authoring.