Analytical solution for heat conduction due to a moving Gaussian heat flux with piecewise constant parameters

We provide an analytical solution of the heat equation in the half-space subject to a moving Gaussian heat flux with piecewise constant parameters. The solution is of interest in powder bed fusion applications where these parameters can be used to control the conduction of heat due to a scanning beam of concentrated energy. The analytical solution is written in a dimensionless form as a sum of integrals over (dimensionless) time. For the numerical computation of these integrals we suggest a quadrature scheme that utilizes pre-calculated look-up tables for the required quadrature orders. Such a scheme is efficient because the required quadrature orders are strongly dependent on the parameters in the heat flux. The possibilities of using the obtained computational technique for the control and optimization of powder bed fusion processes are discussed

Challenges for Knowledge Communities in Technical Work Domains

By drawing on the specific lessons learned from one case study, this paper will discuss collaboration, and issues upon knowledge communities in technical work domains. The results are based on a case study in a manufacturing process, thermal spraying, which can be characterised as very complex and technical. In order to understand the concept of knowledge communities in technical work domains I argue for an elaborated approach by going across different collaboration levels and organisational cultures, into issues of communities of practice. The discussion ends up with three main challenges for forming and supporting knowledge communities. These challenges might inspire an adequate work milieu, cultivated by both shared meanings and technology support

The Dynamics Of Interaction: Exploring A Living Lab Innovation Process From A Community Of Practice Perspective

This paper is based on a living lab project, which is an open, user-centric, innovation approach, where several actors from industry, user groups and academia are involved. The research question is: How can interaction dynamics be understood in a living lab innovation process? We applied an action-oriented research approach, where the empirical results are from The Find Project (TFP), which aim is to customize an ICT product based on the needs of a user group. The findings are analyzed from a community of practice perspective where three different communities, i) researchers from Halmstad Living Lab (HLL), ii) ICT developers (ICTD) and iii) next of kin of demented elderly persons (NOKD), represented the unit of analysis. We identified situations and activities that played a vital role for the innovation process in terms of boundary interaction dynamics. The contribution of our research to innovation theory is a combination and further exploration of the boundary spanning and communities of practice theories. We have developed a conceptual model describing the dynamics in boundary interactions of an ICT innovation process with regard to boundary objects-inuse and brokering. The conceptual model highlights two different levels of brokering: i) inner-level brokering and ii) outer-level brokering

Boundary dialogues in user-centric innovation

This paper is based on a user-centric innovation project, Free2Ride, which is seen as an example of community interaction that overcomes boundaries. Free2Ride aimed at developing a piece of ICT safety equipment consisting of a sender (on the horse) and a receiver (application in a smartphone) to be used by equestrian club members during their everyday riding activities. We will answer the research question of what the characteristics of a boundary dialogue in user-centric innovation activities are. The aim of the paper is to propose a model describing the characteristics of boundary dialogue in user-centric innovation that involve different communities of practices such as ICT developers, users and researchers. We applied a combination of research approaches consisting of action research and engaged scholarship approach. The theoretical framework for analyzing our findings is communities of practices with a specific interest in boundary spanning and learning dialogues. Our contribution is a model describing the characteristics of boundary dialogues in user-centric innovation. An important element of that model is the mental wandering, inwards and outwards, by core members in a community. We discuss the temporal as well as the symbolic nature of the mental wandering during the boundary dialogue in user-centric innovation activities

A greedy algorithm for optimal heating in powder-bed-based additive manufacturing

Powder-bed-based additive manufacturing involves melting of a powder bed using a moving laser or electron beam as a heat source. In this paper, we formulate an optimization scheme that aims to control this type of melting. The goal consists of tracking maximum temperatures on lines that run along the beam path. Time-dependent beam parameters (more specifically, beam power, spot size, and speed) act as control functions. The scheme is greedy in the sense that it exploits local properties of the melt pool in order to divide a large optimization problem into several small ones. As illustrated by numerical examples, the scheme can resolve heat conduction issues such as concentrated heat accumulation at turning points and non-uniform melt depths

A greedy algorithm for optimal heating in powder-bed-based additive manufacturing

Powder-bed-based additive manufacturing involves melting of a powder bed using a moving laser or electron beam as a heat source. In this paper, we formulate an optimization scheme that aims to control this type of melting. The goal consists of tracking maximum temperatures on lines that run along the beam path. Time-dependent beam parameters (more specifically, beam power, spot size, and speed) act as control functions. The scheme is greedy in the sense that it exploits local properties of the melt pool in order to divide a large optimization problem into several small ones. As illustrated by numerical examples, the scheme can resolve heat conduction issues such as concentrated heat accumulation at turning points and non-uniform melt depths

Boundaries of Logics in Municipality Communicators’ Facebook Practice: Towards a New Public Service Competence

With an increased use of external online platforms, digital government logics are gradually intertwined with external, algorithmic, crowd-influenced value logics of social media platforms. This new scene especially affects administration, which can no longer neutrally deliver public service, but becomes involved in processes of consideration and judging what rules and traditions seem most appropriate in the situation. Through deep interviews and workshops with municipal communicators, we examine this balancing act when communicators use social media for external communication. We use a practice perspective to characterize and conceptualize an emerging approach to public service