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Understanding radiation-generated electronic traps in radiation dosimeters based on organic field-effect transistors
No full textOrganic dosimeters offer unique advantages over traditional technologies, and they can be used to expand the capabilities of current radiation detection systems. In-depth knowledge of the mechanisms underlying the interaction between radiation and organic materials is essential for their widespread adoption. Here, we identified and quantitatively characterized the electronic traps generated during the operation of radiation dosimeters based on organic field-effect transistors. Spectral analysis of the trap density of states, along with optical and structural studies, revealed the origin of trap states as local structural disorder within the crystalline films. Our results provide new insights into the radiation-induced defects in organic dosimeters, and pave the way for the development of more efficient and reliable radiation detection devices
Pilot assignment and power control in secure UAV-enabled cell-free massive MIMO networks
Get PDFThis paper investigates the pilot assignment and power control problems for secure UAV communications in cell-free massive MIMO network with the user-centric scheme, where numerous distributed access points (APs) simultaneously serve multiple UAVs and terminal users. Meanwhile, there exists one UAV acting as an eavesdropper which can perform pilot spoofing attack. Considering a mixture of Rayleigh and Ricean fading channels, the APs respectively perform MMSE estimation and distributed conjugate beamforming for uplink training and downlink data transmission. Using random matrix theory, the closed-form expression for a tight lower bound on the achievable secrecy rate is derived, which enables the impact analysis of key parameters, such as power, antenna configuration, UAV height, etc. Taking into account both performance and complexity, a novel pilot assignment scheme is proposed by combining weighted graphic framework and genetic algorithm, which can actualize global search with limited iterations. The max-min power control with security constraints is then studied in parallel, which can not only enhance the network fairness but also ensure the security. Accordingly, successive convex approximation and fractional optimization are jointly utilized to solve this non-convex problem. Simulation results numerically verify the analytical results and indicate the superiority of the proposed pilot assignment and power control schemes
Exploring online consumer review-management response dynamics : a heuristic-systematic perspective
Get PDFAlthough the effects of managerial responses (MRs) on subsequent customer reviews (CRs) has been explored, we lack a comprehensive theoretical framework to explain the interdependent relationships between previous and subsequent CRs—specifically the dynamic influences of MRs on future CRs. We draw on emotional contagion and regulation theories to develop a heuristic systematic model to explain CR-MR dynamics in online settings. We propose six systematic processing and three heuristic processing routes to delineate the determination and persuasion effects between previous and subsequent consumers' CRs. The systematic routes describe how current customers' compliments, complaints, and emotions influence their current rating scores. The heuristic processing routes describe how previous customers' rating scores and emotions influence current customers' rating scores and emotions. We suggest MR strategies to regulate these effects. The presence and length of MRs defines the numeric heuristic route while the positive-emotion heuristic route is conceptualized through expressions of thanks, sincerity, interaction, and complimenting customers. Expressions of apology, explanation, empathy, and remedy inform the negative-emotion heuristic route. We collect text from customers' reviews and managers' responses from the TripAdvisor website using text-mining techniques and analyze our hypotheses using Pooled Ordinary Least Squares (pooled OLS) and Generalized Method of Moment (GMM) modeling. Our findings not only enrich the theoretical underpinnings of the CR/MR literature, but also provide managerial guidance on how customers' emotional contagion and rating behaviors might be regulated
Quantitative evaluation of The Imagineerium education project by students : introducing the trowsdale index of confidence in experiential learning
Get PDFThe Imagineerium is an arts and engineering based curriculum project designed to enhance student confidence in learning. This study reports on the development of the Trowsdale Index of Confidence in Experiential Learning, an instrument designed to conceptualise and operationalise a four-component model of confidence in experiential learning appropriate for upper primary school students, embracing confidence in creativity, confidence in competence, confidence in collaboration, and confidence in learning. Data provided by 140 9- to 10-year-old students both before and after participating in the 10-week programme, demonstrated a significant increase in scores on this measure at time two, although there was no increase in scores on a control variable hypothesised not to be influenced by the intervention
Countercartographies of copper : Martha Rosler, Chris Kraus and the Great Arizona Copper Strike of 1983-1986
Get PDFChris Kraus is often read as a chronicler of women artists’ experience: their frustrated desires, stifled creativity and stolen labour. But while these are the struggles that her protagonists face, the novel sets such struggles within the pressing context of American Empire's expansion and reorganisation in the post-Vietnam era. The juxtaposition between these levels is what generates the drama of Kraus’ work. Foregrounding these juxtapositions, this article situates Kraus’ novels within a longer tradition of feminist conceptual artists like Martha Rosler who took the labour and domination of predominantly white middle-class housewives as a standpoint from which to attempt to understand the expansion of US-backed global capitalism. Specifically, the article draws on the concept of ‘countertopographies’ developed by feminist geographer Cindi Katz to argue that Rosler and Kraus’ work offers a form of ‘countertopographic aesthetics’. That is, they both turn to the sphere of the reproductive as a site from which to map the uneven effects of global capitalism, while also foregrounding their own uneasy relationship with the imperialist project of mapping itself, by drawing attention to the ideological practices and limits of their very mappings. To illustrate this claim, the article concludes by turning to a partially buried event in Kraus’ Summer of Hate (2012): the 1983 Clifton-Morenci Copper Strike, a crucial but often overlooked flashpoint in the roll-out of neoliberalism. This eighteen-month strike was fought by a largely Mexican-American workforce, and the Women's Auxiliary, who joined a long history of working-class housewives like the Housewives’ Committee of Siglo X in Bolivia in becoming strike leaders. I argue that the strike is both crucial to the conjecture that Kraus’ narrative traces, and also illuminating of the limit point of the protagonists’ politics and the form of mapping that is possible from such a perspective
Uncovering crystallization mechanisms of SiO2-MnO based welding fluxes
No full textUnderstanding the crystallization mechanism of flux is critical to tailoring welding processes and thus improving welding performance. However, reproducing or directly observing the flux crystallization process during welding is not feasible due to technical limitations. Here, we report a strategy capturing the crystallization features of SiO2–MnO based fluxes by analyzing post-welding slags. Moreover, crystallization mechanisms of the slags have also been elucidated by molecular dynamics simulations and thermodynamic approaches. Our findings reveal that the crystallization fraction is significantly enhanced from 0 to 100 % with a substitutin of TiO2 for SiO2, but is moderately reduced from 70.68 to 61.96 % upon substituting MnO with CaO. Such distinct phenomena have been associated with the fact that crystal nucleation and growth are subjected to thermodynamic and kinetic factors, including degree of structural polymerization, bond distributions, and atomic diffusion capacity. These insights will facilitate tackling practical challenges pertinent to precisely controlling flux crystallization behaviors through compositional adjustment
Three decades of EU climate policy : racing toward climate neutrality?
Get PDFThe European Union (EU) began developing climate policy in the 1990s. Since then, it has built up a broad portfolio of mitigation policy measures and governance tools, including legally binding targets to reduce greenhouse gas (GHG) emissions, and policy measures addressing emissions trading, renewable energy, energy efficiency, and more. In 2019, the European Commission—the EU's executive arm—published the European Green Deal (EGD), an overarching policy framework to achieve the goal of climate neutrality by 2050. The EGD aims to push EU climate policy and governance far beyond incremental policy development. In this article, we ask: does the EGD represent a break from past patterns of EU climate governance? We argue that it maintains several past patterns, but nevertheless breaks from other established policy and governance trends. We review insights from politicization and new institutionalist theoretical lenses to help us understand these findings. We reveal certain tensions and challenges inherent in the EU's climate governance approach—around speed and coherence, effectiveness and just transition—that highlight future research needs, and raise questions about the EU's ability to implement its climate policy goals. This article is categorized under: Policy and Governance > Multilevel and Transnational Climate Change Governanc
Feminist theories and activist practices in organization studies
Get PDFThis piece reflects on the untapped potential of feminist theories and activist practices to address vital organizational issues and societal challenges such as inequality, sustainability, and care for the environment. While we recognize and briefly review the progress on gender issues in organization studies achieved over the last decades, our focus is on identifying the critical and underutilized strands of feminist thinking offering fresh responses to these problems, including decolonial feminism, feminist ethics of care, posthuman feminism, and ecofeminism. By way of illustrating our theoretical arguments, we discuss how five different papers recently published in Organization Studies address some of these issues, including the uncovering hidden entanglements of power and performativity in a global bank and in the beauty industry by paying attention to body and affect, the underrepresented struggles of women in the Global South as they disrupt gendered practices through consciousness raising, contesting gender regimes at organizational social events, and finally, how the social media operate at the intersection of gender and occupation. We conclude by outlining future directions for research as we discuss the contributions of anti-racist feminist theory and decolonial feminist practice to completing the unfinished project of social change while making our scholarship more reflexive and inclusive
The performance and appearance of confidence among the enslavers of South Carolina and Cuba
No full textFor decades the public and private documents of enslavers have been examined to produce seminal studies of slavery. This article explores the interval between public and private, exposing it as a liminal space of emotional direction for the enslaving elite of nineteenth-century South Carolina and Cuba. Consulting confidential correspondence, periodicals, and published proclamations gathered from archives across Cuba, Spain, and the U.S., this study focusses upon instances when enslavers strategized as to how their violence, words, architectural surroundings, legal codification, and press should best buttress what they regarded as the necessary emotional balance for maintaining their dominance: white confidence and Black fear. Analyzing these words and actions using History of the Emotions methodologies and principles including emotionology, emotional regimes, and the emotional politics of slavery, this article contributes the theorization of the ‘confidence script’, a performative narrative style deployed by proslavery elites to publicly assert unalloyed white composure regardless of tangible unrest among the enslaved population, or furtive admissions of slaveholder dread. Its conclusion asserts that the silences and proclamations surrounding racialised white fear and performative confidence in Cuba and the U.S. continue to propagate and justify nefarious white violence and injustice against Black Cubans and Americans today