4,167 research outputs found

    Meso-scale FDM material layout design strategies under manufacturability constraints and fracture conditions

    Get PDF
    In the manufacturability-driven design (MDD) perspective, manufacturability of the product or system is the most important of the design requirements. In addition to being able to ensure that complex designs (e.g., topology optimization) are manufacturable with a given process or process family, MDD also helps mechanical designers to take advantage of unique process-material effects generated during manufacturing. One of the most recognizable examples of this comes from the scanning-type family of additive manufacturing (AM) processes; the most notable and familiar member of this family is the fused deposition modeling (FDM) or fused filament fabrication (FFF) process. This process works by selectively depositing uniform, approximately isotropic beads or elements of molten thermoplastic material (typically structural engineering plastics) in a series of pre-specified traces to build each layer of the part. There are many interesting 2-D and 3-D mechanical design problems that can be explored by designing the layout of these elements. The resulting structured, hierarchical material (which is both manufacturable and customized layer-by-layer within the limits of the process and material) can be defined as a manufacturing process-driven structured material (MPDSM). This dissertation explores several practical methods for designing these element layouts for 2-D and 3-D meso-scale mechanical problems, focusing ultimately on design-for-fracture. Three different fracture conditions are explored: (1) cases where a crack must be prevented or stopped, (2) cases where the crack must be encouraged or accelerated, and (3) cases where cracks must grow in a simple pre-determined pattern. Several new design tools, including a mapping method for the FDM manufacturability constraints, three major literature reviews, the collection, organization, and analysis of several large (qualitative and quantitative) multi-scale datasets on the fracture behavior of FDM-processed materials, some new experimental equipment, and the refinement of a fast and simple g-code generator based on commercially-available software, were developed and refined to support the design of MPDSMs under fracture conditions. The refined design method and rules were experimentally validated using a series of case studies (involving both design and physical testing of the designs) at the end of the dissertation. Finally, a simple design guide for practicing engineers who are not experts in advanced solid mechanics nor process-tailored materials was developed from the results of this project.U of I OnlyAuthor's request

    Examining the Impact of Personal Social Media Use at Work on Workplace Outcomes

    Get PDF
    A noticable shift is underway in today’s multi-generational workforce. As younger employees propel digital workforce transformation and embrace technology adoption in the workplace, organisations need to show they are forward-thinking in their digital transformation strategies, and the emergent integration of social media in organisations is reshaping internal communication strategies, in a bid to improve corporate reputations and foster employee engagement. However, the impact of personal social media use on psychological and behavioural workplace outcomes is still debatebale with contrasting results in the literature identifying both positive and negative effects on workplace outcomes among organisational employees. This study seeks to examine this debate through the lens of social capital theory and study personal social media use at work using distinct variables of social use, cognitive use, and hedonic use. A quantitative analysis of data from 419 organisational employees in Jordan using SEM-PLS reveals that personal social media use at work is a double-edged sword as its impact differs by usage types. First, the social use of personal social media at work reduces job burnout, turnover intention, presenteeism, and absenteeism; it also increases job involvement and organisational citizen behaviour. Second, the cognitive use of personal social media at work increases job involvement, organisational citizen behaviour, employee adaptability, and decreases presenteeism and absenteeism; it also increases job burnout and turnover intention. Finally, the hedonic use of personal social media at work carries only negative effects by increasing job burnout and turnover intention. This study contributes to managerial understanding by showing the impact of different types of personal social media usage and recommends that organisations not limit employee access to personal social media within work time, but rather focus on raising awareness of the negative effects of excessive usage on employee well-being and encourage low to moderate use of personal social media at work and other personal and work-related online interaction associated with positive workplace outcomes. It also clarifies the need for further research in regions such as the Middle East with distinct cultural and socio-economic contexts

    The Digital Continent:Placing Africa in Planetary Networks of Work

    Get PDF
    Only ten years ago, there were more internet users in countries like France or Germany than in all of Africa put together. But much has changed in a decade. The year 2018 marks the first year in human history in which a majority of the world’s population are now connected to the internet. This mass connectivity means that we have an internet that no longer connects only the world’s wealthy. Workers from Lagos to Johannesburg to Nairobi and everywhere in between can now apply for and carry out jobs coming from clients who themselves can be located anywhere in the world. Digital outsourcing firms can now also set up operations in the most unlikely of places in order to tap into hitherto disconnected labour forces. With CEOs in the Global North proclaiming that ‘location is a thing of the past’ (Upwork, 2018), and governments and civil society in Africa promising to create millions of jobs on the continent, the book asks what this ‘new world of digital work’ means to the lives of African workers. It draws from a year-long fieldwork in South Africa, Kenya, Nigeria, Ghana, and Uganda, with over 200 interviews with participants including gig workers, call and contact centre workers, self-employed freelancers, small-business owners, government officials, labour union officials, and industry experts. Focusing on both platform-based remote work and call and contact centre work, the book examines the job quality implications of digital work for the lives and livelihoods of African workers

    Internationalisation dynamics in contemporary South American life sciences: the case of zebrafish

    Get PDF
    We tend to assume that science is inherently international. Geographical boundaries are not a matter of concern in science, and when they do – e.g. due to the rise of nationalist or populist movements – they are thought to constitute a threat to the essence of the scientific enterprise; namely, the global mobility of ideas, knowledge and researchers. Quite recently, we also started to consider that research could become ‘more international’ under the assumption that in doing so it becomes better, i.e. more collaborative, innovative, dynamic, and of greater quality. Such a positive conceptualisation of internationalisation, however, rests on interpretations coming almost exclusively from the Global North that systematically ignore power dynamics in scientific practice and that regard scientific internationalisation as an unproblematic transformative process and as a desired outcome. In Science and Technology Studies (STS), social research on model organisms is perhaps the clearest example of the influence of the dominant vision of internationalisation. This body of literature tends to describe model organism science and their research communities as uniform and harmonious international ecosystems governed by a strong collaborative ethos of sharing specimens, knowledge and resources. But beyond these unproblematic descriptions, how does internationalisation actually transform research on life? To what extent do the power dynamics of internationalisation intervene in contemporary practices of knowledge production and diffusion in this field of research? This thesis revisits the dynamics and practices of scientific internationalisation in contemporary science from the perspective of South American life sciences. It takes the zebrafish (Danio rerio), a small tropic freshwater fish, originally from the Ganges region in India and quite popular in pet shops, as a case study of how complex dynamics of internationalisation intervene in science. While zebrafish research has experienced a remarkable growth in recent years at the global scale, in South America its growth has been unprecedented, allowing average laboratories, which often operate with small budgets and with less well-developed science infrastructures, to conduct world-class research. My approach is based on a consideration of internationalisation as a conceptual model of change. I consider internationalisation to be a process essentially marked by tensions in the spatial, cognitive and evaluative dimensions of scientific practice. These tensions, I claim, are not just a key feature of internationalisation, but also aspects of a conceptual opposition that is geared towards explaining how change comes about in science. By studying the dynamics of internationalisation, I seek to understand various transformations of zebrafish research: from its construction as a research artefact to its diffusion across geographical boundaries. My focus on South America, on the other hand, helps me to understand the complexity of such dynamics beyond the lenses of the dominant discourse of internationalisation that prevails in the STS literature on model organisms. I use mixed-methods (i.e. semi-structured interviews, document analysis, bibliometrics and social network analysis) to observe and interpret transformations of internationalisation at different scales and levels. My analysis suggests first, that internationalisation played an important role in the construction of the zebrafish as a model organism and that, in the infrastructures and practices of resource exchange that sustain the scientific value of the organism internationally, dynamics of asymmetry and empowerment problematise the collaborative ethos of this community. Second, I found that collaborative networks – measured through co-authorships – also played an important role in the diffusion of zebrafish as a model organism in South America. However, I did not find a clear indication of international dependency in the diffusion of zebrafish, explained by a geographical concentration of scientific expertise in the zebrafish collaboration network. Rather than exposing peripheral researchers to novel ideas, networks of international collaboration seem to be more related to access to privileged material infrastructures resulting from the social organisation of scientific labour worldwide. Lastly, by examining practices of biological data curation and researchers’ international mobility trajectories, I describe how dynamics of internationalisation shape the notion of research excellence in model organism science. In this case, I found mobility trajectories to play a key role in boosting researchers’ contributions to the community’s database, especially among researchers from peripheral communities like South America. Overall, while these findings show the value of considering internationalisation as a conceptual model of change in science, more research is needed on the intervention of complex dynamics of internationalisation in other cases and fields of research

    Abstracts

    Get PDF

    Network failure: digital technology in sponsored search advertising

    Get PDF
    The current study advances understanding of sponsored search advertising (SSA) by exploring failures in networks of SSA tools and human actors. SSA represents a novel form of information technology-bound marketing practice that has rapidly proliferated marketing over the last 25 years. The confluence of search technology and advertising has redefined how contemporary marketing is practiced, causing significant redistribution in marketing spent, advertising activity and the emergence of new actors. These shifts have attracted significant interest with rapidly growing number of studies addressing matters around SSA strategy, including various SSA features and functions. In radical departure from mainstream SSA literature, the current study adopts a practice-based view to provide a more nuanced understanding of how the networks of human and technological actors emerge, are stabilised and fail in SSA. By casting SSA as networked practice, the study highlights social construction and the dynamic, multiple and fluid nature of SSA. Actor network theory (ANT) theoretically frames failure in SSA and the networked nature of human and nonhuman actors that contribute to it. The study adopts a qualitative research design, where the data was collected through a 7-month ethnography and the data set includes semi-structured and insitu interviews, day-to day (participant) observations, images, field notes, secondary data and a detailed research diary. The data is anchored on events made up of relations – the principal units of analysis. The findings are presented as a set of ethnographic stories from problematised events. They show how SSA dynamism, fluidity and multiplicity can only be acknowledged accurately enough if human and nonhuman actors in networks are followed in their attempts to build heterogeneous relations. This enables enactment of several new actors, intentions and roles from the Google advertising practice in a specialised SSA agency. The findings provide novel insights that address several gaps in the marketing literature

    BCE KSZI Reader 2022

    Get PDF
    A kötet oktatĂĄsi cĂ©lokat szolgĂĄl. A szöveggyƱjtemĂ©nyben szereplƑ tanulmĂĄnyok mĂĄsodközlĂ©sek, azokra hivatkozni az eredeti megjelenĂ©si helyĂŒkön kell
    • 

    corecore