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Unraveling Propylene Oxide Formation in Alkali Metal Batteries
Get PDFThe increasing need for electrochemical energy storage drives the development of post-lithium battery systems. Among the most promising new battery types are sodium-based battery systems. However, like its lithium predecessor, sodium batteries suffer from various issues like parasitic side reactions, which lead to a loss of active sodium inventory, thus reducing the capacity over time. Some problems in sodium batteries arise from an unstable solid electrolyte interphase (SEI) reducing its protective power e. g., due to increased solubility of SEI components in sodium battery systems. While it is known that the electrolyte affects the SEI structure, the exact formation mechanism of the SEI is not yet fully understood. In this study, we follow the initial SEI formation on a piece of sodium metal submerged in propylene carbonate with and without the electrolyte salt sodium perchlorate. We combine X-ray photoelectron spectroscopy, gas chromatography, and density functional theory to unravel the sudden emergence of propylene oxide after adding sodium perchlorate to the electrolyte solvent. We identify the formation of a sodium chloride layer as a crucial step in forming propylene oxide by enabling precursors formed from propylene carbonate on the sodium metal surface to undergo a ring-closing reaction. Based on our combined theoretical and experimental approach, we identify changes in the electrolyte decomposition process, propose a reaction mechanism to form propylene oxide and discuss alternatives based on known synthesis routes
Dynamics of parafermionic states in transport measurements
No full textAdvances in hybrid fractional quantum Hall (FQH)-superconductor platforms pave the way for realisation of parafermionic modes. We analyse signatures of these non-abelian anyons in transport measurements across devices with Z6 parafermions (PFs) coupled to an external electrode. Simulating the dynamics of these open systems by a stochastic quantum jump method, we show that a current readout over sufficiently long times constitutes a projective measurement of the fractional charge shared by two PFs. Interaction of these topological modes with the FQH environment, however, may cause poisoning events affecting this degree of freedom which we model by jump operators that describe incoherent coupling of PFs with FQH edge modes. We analyse how this gives rise to a characteristic three-level telegraph noise in the current, constituting a very strong signature of PFs. We discuss also other forms of poisoning and noise caused by interaction with fractional quasiparticles in the bulk of the Hall system. We conclude our work with an analysis of four-PF devices, in particular on how the PF fusion algebra can be observed in electrical transport experiments
Demonstration of Thermoradiative Power Generation Using Compensated Infrared Rectennas
No full textThermoradiative devices convert low-temperature waste heat to electricity. These devices harvest heat and generate energy using deep space as a heat sink by radiating through the 8 to 13 μm atmospheric window. Infrared rectennas, which consist of ultrahigh speed diodes coupled to micrometer-scale antennas, can be tuned to these frequencies and are a good candidate for thermoradiative power generation at room temperature, if certain challenges can be circumvented. Practical optical rectennas require a high diode conversion efficiency, a high coupling efficiency between the diode and antenna, and a large array of devices sufficient to produce significant power. The novelty of our approach lies in designing and building a diode compensation structure at terahertz and arraying 250000 diodes, two approaches that have never been reported before. We demonstrate that a Ni/NiO/Al2O3/Cr/Au metal-double insulator-metal (MI2M) diode-based infrared rectenna with a 2.5 μm transmission line compensation structure in a staggered array can produce power from a temperature difference, and with development, it has the potential to produce competitive power outputs
Organising grassroots infrastructure: The (in)visible work of organisational (in)completeness
Get PDFIn this article we build on the concept of incompleteness, as recently developed in both organisational and urban studies, to improve our understanding of the collective actions of grassroots organisations in creating and governing critical infrastructures in the changing and resource-scarce contexts of urban informal settlements. Empirically, the article is informed by the case of resident associations providing critical services and infrastructure in informal settlements in Kisumu, Kenya. Findings suggest three organisational processes that grassroots organisations develop for the production and governance of incomplete grassroots infrastructures: shaping a partial organisation but creating the illusion of a formal and complete organisation; crafting critical (and often hidden) material and organisational infrastructures for the subsistence of dormant (but still visible) structures; and moulding nested infrastructure that shelters layers of floating and autonomous groups embedded in communities. In a resource-poor environment, the strategy is to create incompleteness, less organisation and to keep it partial and limited to a minimum of elements. The article also explores the political implications of organisational and infrastructural incompleteness by examining how it leads to efforts to craft loose and ambiguous governmental arrangements, connecting them materially and politically to formal infrastructure systems. These governmental arrangements are shifting and in the making, and therefore also incomplete. The article reveals how grassroots organisations mobilise a wide range of (in)visibility approaches. It concludes by exposing the hidden power of \u27incompleteness\u27 and the potential in hiding certain elements of incompleteness from outsiders, while rendering other elements visible when perceived as useful
Science parks as key players in entrepreneurial ecosystems
Get PDFThis study explores the crucial role of modern science parks in the creation, development, and management of entrepreneurial ecosystems. Thus, it has developed a conceptual framework for analysing the role that science parks could have in developing an entrepreneurial ecosystem. We interviewed several stakeholders in the entrepreneurial ecosystem oriented towards sustainable production. The study design comprises three levels of analysis: 27 nodes, 7 themes, and 3 aggregate dimensions. While a science park can play a key role in creating, developing, and managing an entrepreneurial ecosystem, we find that its success largely depends on the level of cooperation among the key stakeholders. This study provides new insights into (i) how we can better comprehend the emergence of linkages to develop entrepreneurial ecosystems and (ii) how science park managers and regional policymakers can better examine the role of key stakeholders in envisioning, configuring, and enabling regional entrepreneurial ecosystems. When studying science parks, it is important to use a holistic approach, focusing on the key players in the entrepreneurial ecosystem - science parks and their stakeholders - and knowing how and when to intervene
Patent management: The prominent role of strategy and organization
No full textThe purpose of this article is twofold; to verify the existence of different profiles of firms based on the level of sophistication of their patent management core processes, and to test the impact of the interplay between two patent management supporting dimensions, namely patent strategy and organization for patenting, on the level of sophistication of patent management core processes.\ua0The method consists of a survey study, collecting data from a set of European patent management professionals. This data is analyzed with factor analysis, cluster analysis, and regression analysis to test a number of hypotheses.\ua0The results show that patent strategy positively and significantly impacts patent management sophistication, and that the patent organization positively moderates this relationship. In other words, a patent strategy, supported by a well-developed patent organization and culture, will positively influence the processes of managing a firm’s patent portfolio.\ua0This study is, to our knowledge, the first one to provide quantitative evidence that supports the notion that it is important to take a strategic and organizational perspective of patent management
Phytobiotic potential of Teucrium polium phenolic microcapsules against Salmonella enteritidis infection in mice
No full textSalmonella\ua0infection is a major public health issue worldwide. Given the alarming increase in infections with antibiotic-resistant microorganisms and side effects of synthetic antibiotics, there is an\ua0increasing interest in medicinal plants as natural alternatives to synthetic drugs to combat antibiotic-resistant microorganisms. The present study investigated the biological properties and health-promoting effects of microencapsulated phenolic compounds of Teucrium polium leaves as a dietary phytobiotic in mice challenged by Salmonella enteritidis. Microcapsules showed a capsulation efficiency of 93.6% with a particle size of 1261.8\ua0nm with antioxidant and antibacterial activities in-vitro. The phytochemical analysis confirmed the presence of various phenolic compounds, i.e., ferulic acid, cinnamic acid, gallic acid, caffeic acid, salicylic acid, catechin, ellagic acid, and chrysin ranged between 121.6 and 975.3\ua0\ub5g/g DW. The microencapsulated phenolics exhibited improvement in the growth, liver function, morphometric parameters of ileum, antioxidant- and inflammation-related gene expression and inhibited the ileal population of S. enteritidis in mice challenged by S. enteritidis infection. The microencapsulated phenolics from T. polium leaves could be a promising phytobiotic approach to combat S. enteritidis infections
Be prepared and do the best you can: a focus group study with staff on the care environment at Swedish secure youth homes
Get PDFPURPOSE: This study examined staff members\u27 experiences of the institutional care environment within secure youth homes. METHODS: Data were collected through three focus group discussions with 17 staff members at two secure youth homes. Subsequently, a thematic analysis was conducted. RESULTS: The analysis indicated two main themes: risk management and damage control in a restricted environment and compensating and reconstructing ordinariness-trying to make the best of it; each theme had three subthemes. The care environment seems to be experienced by staff as characterized by conflicting demands, thus constituting a gap between needs and what is possible to achieve-a balancing act that constitutes a constant struggle. CONCLUSIONS: The staff members\u27 constant struggle could be interpreted as conflicting moral and instrumental demands; they know what the youths need, but the environment of the secure youth homes demands the decorous behaviour of sociomaterial control practices-rather than care practices
Shaping Engineers, Making Gender Politics: Swedish Universities of Technology and the Creation of a Policy Field, 1976–1998
Get PDFDespite a global reputation as a gender-equal nation, the labour market in Sweden is segregated. This particularly applies to engineering. Five decades of national gender equality policies and engineering recruitment campaigns have only partially transformed the situation. This thesis combines the study of two parallel and interlinked phenomena: the development of Swedish engineering education and profession, and the evolution of a national gender equality policy field. It examines how the Swedish engineering profession – represented by the universities of technology – from the mid-1970s, responded to demands from both national policies and from within the engineering communities. The push to act went in two directions; national policies pressured universities of technology to take measures, and representatives from the engineering communities often shaped gender equality policies. How engineering educators steered definitions of gender equality and the corresponding solutions in directions that suited their professional needs are at the heart of the analysis here. Drawing on previously unexplored archival sources and interviews and deploying a theoretical framework of professional boundary work (Thomas F. Gieryn), the dissertation argues that the Swedish male-dominated engineering profession, represented by their technical universities, conducted gender equality politics. The study adds to an emerging international research field on the history of gendered engineering (e.g. Amy Sue Bix, Nathan Ensmenger, Laura Ettinger, Mar Hicks, Alice Clifton-Morekis, Londa Schiebinger, Karin Zachmann) and the Swedish historiography of national gender equality politics. It presents Swedish historiography on the gendered culture in engineering and national gender equality policy to an international audience
From the Ground Up: Designerly Knowledge in Human-Drone Interaction
Get PDFThere are flying robots out there — you may have seen and heard them, droning over your head. Drones have expanded our human capacities, lifting our sight to the skies, but not without generating intricate experiences. How are these machines being designed and researched? What design methods, approaches, and philosophies are relevant to the study of the development (or decline) of drones in society? In this thesis, I argue that we must re-frame how drones are studied, from the ground up, through a design stance. I invite you to take a journey with me, with changing lenses from the work of others to my own intimate relationship with this technology. My work relies on exploring the fringes of design research: understudied groups such as children, alternative design approaches such as soma design, and peripheral methods such as autoethnography.This thesis includes four articles discussing perspectives on designerly knowledge, composing a frame surrounding the notion that we may be missing out on some of the aspects of the wicked nature of human-drone interaction (HDI) design. The methods are poised on phenomenology and narratives, and supported by the assumption that any subject of study is a sociotechnical assemblage. Starting through a first-person perspective, I offer a contribution to the gap in research through a longitudinal autoethnographic study conducted with my children. The second paper comes in the form of a pictorial expressing a first-person experience during a design research workshop, and what that meant for my relationship with drones as a research material. The third paper leaps into a Research through Design project, challenging the solutionist drone and offering instead the first steps in a concept-driven design of the unlikely pairing of drones and breathing. The fourth paper returns to the pictorial form, suggesting a method for visual conversations between researchers through the tangible qualities of sketches and illustrations. Central to this thesis, is the argument for designerly approaches in HDI and championing the need for alternative forms of publication and research. To that end, I include two publications in the form of pictorials: a publication format relying on visual knowledge and with growing interest in the HCI community