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This paper aims to develop an innovative 3D printer based on material extrusion to expand applied material field and shorten the production cycle. The developed 3D printer can fabricate products directly using various powders, including polymers and fillers. In addition, the influence of extrusion on the orientation of thermal conductive filler is also investigated.

To ensure the plasticizing effect and the mixing ability, the printing head is a conical twin-screw extruder, which have a smaller volume. PA12 and h-BN powders were selected for printing as matrix and filler, respectively. The properties of printing products were characterized.

The results show that the new printer can fabricate products directly using polymer powders because of the mixing ability of the twin-screw. The h-BN filler orient in the PA12 matrix and form thermal conduction paths due to the extrusion process, which make the printed samples have an anisotropic thermal conductivity.

The innovative 3D printer provides a method of printing products directly using powders, which can expand material field and shorten the production cycle. For composites, the extrusion process can make fillers orient in the matrix to fabricate products with anisotropic characteristics.

The purpose of this paper is to compare different powder metallurgy (PM) processes to produce ceramic parts through additive manufacturing (AM). This creates the potential to rapidly shape ceramic parts with an almost unlimited shape freedom. In this paper, alumina (Al₂O₃) parts are produced, as Al₂O₃ is currently the most commonly used ceramic material for technical applications.

Variants of the following PM route, with indirect selective laser sintering (indirect SLS) as the AM shaping step, are explored to produce ceramic parts: powder synthesis, indirect SLS, binder removal and furnace sintering and alternative densification steps.

Freeform-shaped Al₂O₃ parts with densities up to approximately 90 per cent are obtained.

The resulting Al₂O₃ parts contain inter-agglomerate pores. To produce higher-quality ceramic parts through indirect SLS, these pores should be avoided or eliminated.

The research is innovative in many ways. First, composite powders are produced using different powder production methods, such as temperature-induced phase separation and dispersion polymerization. Second, four different binder materials are investigated: polyamide (nylon-12), polystyrene, polypropylene and a carnauba wax – low-density polyethylene combination. Further, to produce ceramic parts with increased density, the following densification techniques are investigated as additional steps of the PM process: laser remelting, isostatic pressing and infiltration.

This study aims to evaluate and compare the macroscopic properties of commercial acrylonitrile-butadiene-styrene (ABS) processed by two different types of additive manufacturing (AM) machines. The focus is also on the effect of multiple closed-loop recycling of ABS.

A conventional direct-drive, Cartesian-type machine and a Bowden, Delta-type machine with an infrared radiant heating system are used to manufacture test specimens molded in ABS. Afterward, multiple closed-loop recycling cycles are conducted, involving consecutive AM (four times) and recycling (three times). The rheological, mechanical, morphological and physicochemical properties are investigated.

The type of machine affects the quality of the produced parts. The machine containing an infrared radiant system in a temperature-controlled chamber produces parts showing higher mechanical properties and filling fraction, although it increases the yellowing. Closed-loop recycling of ABS for AM is applicable for at least two cycles, inducing a slight increase in tensile modulus (ca. 5%) and in tensile strength (ca. 13%) and a decrease in the impact strength (ca. 14%) and melt viscosity. An increase in the filling fraction of the AM parts promotes an increase in tensile strength and tensile modulus, although it does not influence the impact strength. Furthermore, multiple closed-loop recycling does not affect the overall chemical structure of ABS.

Controlling the environmental temperature and using infrared radiant heating during AM of ABS improves the quality of the produced parts. Closed-loop recycling of ABS used in AM is feasible up to at least two recycling steps, supporting the implementation of a circular economy for polymer-based AM.

This study shows original results regarding the assessment of the effect of different types of AM machines on the main end-use properties of ABS parts and the influence of multiple closed-loop recycling on the characteristics of ABS fabricated by the most suited AM machine with an infrared radiant heating system and a temperature-controlled environment.

Austrian economics figures centrally in organizational entrepreneurship research. However, researchers have focussed almost entirely on the Austrian school's “gales of creative destruction” and “entrepreneurial discovery” metaphors, which are rooted in equilibrium assumptions and thus downplay the more subjective and dynamic aspects of entrepreneurship. The purpose of this paper is to question such assumptions, proposing instead a “kaleidic” metaphor drawn from the radical subjectivist strand of Austrian economics. The paper develops, grounds, and enriches the theoretical concepts this metaphor embodies in order to advance the general understanding of entrepreneurship as a radically subjective, disequilibrium phenomenon, as well as the specific knowledge of entrepreneurs’ career and venture experiences. In doing so, the paper highlights creative imagination as a wellspring of entrepreneurship.

The paper employs a case study design to inductively develop the theoretical concepts embodied in the kaleidic metaphor and deductively ground them in the accounts 12 entrepreneurs provided about their career and venture experiences. The paper employs symbolist methods to develop thicker descriptions, generate alternative understandings, and facilitate richer interpretations. Moreover, the paper adopts a reflexive approach in considering the study's implications.

The results suggest the kaleidic metaphor comprises five overarching ideas that resonate, often very strongly, with entrepreneurs.

The study is the first to theoretically develop and empirically ground the ideas the kaleidic metaphor embodies. The paper contributes to a growing body of conceptual work and joins a handful of empirical studies by organizational entrepreneurship scholars using the radical Austrian perspective.

Three different pedagogical approaches grounded in three different definitional foundations of entrepreneurship have been compared in relation to their effects on students. They are: (1) “Idea and Artefact-Creation Pedagogy” (IACP), grounded in opportunity identification and creation, (2) “Value-Creation Pedagogy” (VaCP), grounded in value creation and (3) “Venture-Creation Pedagogy” (VeCP), grounded in organisation creation.

Data were collected at 35 different sites where education was deemed to be entrepreneurial and experiential. A quantitative, smartphone app-based data collection method was used alongside a qualitative interview approach. 10,953 short-survey responses were received from 1,048 participants. Responses were used to inform respondent selection and discussion topics, in 291 student and teacher interviews. Comparative analysis was then conducted.

The three approaches resulted in very different outcomes, both in magnitude and in kind. VaCP had strong effects on entrepreneurial competencies, on student motivation and on knowledge and skills acquisition. VeCP had weaker effects on knowledge and skills acquisition. IACP had weak effects on all outcomes probed for. Differences were attributed to variation in prevalence of certain emotional learning events and to variation in purpose as perceived by students.

VaCP could serve as an escape from the potential dilemma faced by many teachers in entrepreneurial education, of being caught between two limiting courses of action; a marginal VeCP approach and a fuzzy IACP one. This could prompt policymakers to reconsider established policies. However, further research in other contexts is needed, to corroborate the extent of differences between these three approaches.

Most impact studies in experiential entrepreneurial education focus only on organisation-creation-based education. This study contributes by investigating entrepreneurial education that is also grounded in two other definitional foundations. Allowance has been made for novel comparative conclusions.

Despite the prevalence of technology in health care, marketing research on social media in the birthspace is limited. The purpose of this paper is to explore how birthing women leverage social media for transformative well-being in the liminal context of birth.

A qualitative study of women who had recently experienced birth was undertaken. Thematic analysis of data from in-depth interviews reveals birthing women’s digital practices and social media capabilities for well-being in a liminal space.

Within the birthspace, women use social media and digital platforms in an effortful and goal-directed way for role transitions and transformation, curating self and other history, goal striving and normalizing experience. These digital practice styles facilitate consumer integration of the liminal digital birthspace and in situ service encounter enabling diverse value outcomes. Drawing on liminality and social presence theories, the authors interpret these practices as demonstrating three interactive liminal stages of suspending, comprehending and transforming. Multi-modality and rapid connection afforded by digital devices and social media platforms provide social presence (according to perceived immediacy and intimacy) enabling transformative well-being outcomes.

This study is unique, as it provides insights into the traditionally private health service experience of birth. Further, the authors extend the understanding of liminal spaces and use of digital technology, specifically for transformative outcomes, by proposing a framework of consumers’ digital practice styles for well-being in liminal spaces.

The study examines the role that societal levels of self-control – behavioral and cognitive self-control – play in shaping entrepreneurial intentions after both favorable and unfavorable prior exits.

Using Global Entrepreneurship Monitor (GEM) data set on the nature of entrepreneurial exits from 32 countries between 2007 and 2010 and supplementing this data set with country-level scores of behavioral and cognitive self-controls, the authors test five hypotheses on the effects of societal levels of self-control on post-exit entrepreneurial intentions.

The study finds that individuals who exit entrepreneurship for negative reasons (versus positive reasons) are more likely to form entrepreneurial intentions. Further, societal levels of self-control moderate this likelihood.

The study invokes the psychological construct of self-control in the context of entrepreneurship. The novelty lies in rendering self-control as also a higher order societal level construct and then also empirically testing the role that societal self-control plays in shaping entrepreneurial intentions after prior exits. Societal self-control accounts for cross-country variance in why individuals in some societies are better suited and capable to return to entrepreneurship despite unfavorable prior exits.