87,385 research outputs found
Management of the output electrical power in thermoelectric generators
No full textThermoelectric Generators (TEGs) are devices for direct conversion of heat into electrical power and bear a great potential for applications in energy scavenging and green energy harvesting. Given a heat source, the conversion efficiency depends on the available temperature difference, and must be maximized for optimal operation of the TEG. In this frame, the choice of materials with high thermoelectric properties should be accompanied by the identification of criteria for an optimal exploitation of the electrical power output. In this work, we briefly review the main properties of TEGs, focusing on the electrical power output and the thermal-to-electrical conversion efficiency. Besides, we discuss principles of operation of TEGs enabling the optimization of the electrical power output, based on the suitable choice of the electrical load. In particular, we comparatively present and discuss the conditions for matching the electrical load—yielding to maximum power transfer—and those for maximizing the conversion efficiency. We compare the two conditions applying them to the exploitation of a heat reservoir for energy storage and to the recovery of heat from a heat exchanger. We conclude that the difference between the two conditions is not significant enough to justify the complexity required by the implementation of the maximum efficiency. In addition, we consider the effect of the thermal contact resistance on the electrical power output. Using a simple thermal-electrical model, we demonstrate that the equivalent electrical resistance measured between the terminals of the TEG depends on the thermal exchange. Hence, for maximum power transfer, the electrical load of the TEG should not match its parasitic resistance, but the equivalent electrical resistance in each specific operating conditions, which determine the thermal fluxes. The model can be applied for the development of efficient alternative algorithms for maximum power point tracking
Public Sentiments Towards the Arts: A Critical Reanalysis of 13 Opinion Surveys
No full textThis paper summarizes and reviews studies of public perceptions of and sentiments towards the arts. It provides the first critical synthesis of such research based upon original secondary analyses of thirteen of the major data sets collected between 1973 and 1993. In so doing, it reports on what the surveys tell us about several questions of pressing interest to policy makers and others interested in the role of the arts in American society. To what extent do Americans support government funding of the arts, and from what level of government? To what extent do Americans believe that it is important for children to learn about the arts and that the arts are worthy of inclusion in the school curriculum? To what extent do Americans regard the arts as fundamentally important for the quality of community life, on the one hand, or the domain of a select few, on the other? To what extent do sentiments vary between men and women, African-Americans and Euro-Americans, the highly educated and the less schooled, the old and the young, and the wealthy and the less well off? And finally, what, if anything, can we infer about how these patterns have changed over time?
An Organic Electrochemical Transistor fabricated on Waxy-Sublimating Substrates
No full textThe global demand for zero-waste technologies requires the development of electronic devices with sustainable fabrication processes and (ideally) biodegradable materials and substrates. This article reports on the fabrication and electrical characterization of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-based organic electrochemical transistors (OECTs) on naturally degradable cyclododecane (CDD)-based substrates. The electrical performance of the devices is tested in a closed box flushed with nitrogen gas under ambient and different humidity conditions. The devices exhibit an ION/IOFF of more than 103 and transconductance values up to 300 mS. As a proof-of-concept of the potential use of the PEDOT:PSS OECTs for biosensing and environmental monitoring, their application as pH sensors is presented. The sensitivity of 2.25 mS/pH and the signal amplification (up to 50 mS) obtained in this study offer a promising perspective that opens to the formulation of strategies for a more responsible approach to the production and recovery processes of electronic platforms, thus contributing to sustainable technological practices
Mining user habits in smart spaces through process mining techniques
No full textIndependently of the specific task to be enacted in a smart space, it is always crucial to mine a set of models representing environmental dynamics and, noteworthy, user habits and desires. Many different formalisms have been proposed to model human habits, but the vast majority of them are either difficult to read and evaluate or their definition requires a huge amount of work from either experts or users. In this paper we propose to employ process mining techniques in order to model human habits, and we experimentally evaluate such an approach on a dataset built adopting the Smart-Home-in-a-Box toolkit with real users
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
John F. Kennedy telegram to Roosevelt
No full textJersey Homesteads (later the Borough of Roosevelt) was established in the 1930s as an agro-industrial cooperative community. It was established specifically for urban Jewish garment workers, many of whom had emigrated from Europe. President John F. Kennedy sent a telegram to the citizens of Roosevelt, New Jersey, apologizing for not being able to attend the memorial dedication in honor of former President Franklin Delano Roosevelt. (Jersey Homesteads became Roosevelt in 1945 in honor of the president.) President Kennedy expressed his gratitude to the people of Roosevelt for constructing the memorial, and commented that it will serve as a constant reminder of Roosevelt's good works
Ultrasound-guided aspiration and corticosteroid injection of Baker's cysts in knee osteoarthritis: a prospective observational study
No full textTo determine the effect on pain, function, and ultrasonographic findings of ultrasonography-guided Baker's cyst aspiration followed by corticosteroid injection in a group of patients with Baker's cyst secondary to knee osteoarthritis. Prospective observational study. Twenty-six subjects participated in this study. Clinical and instrumental evaluations were performed at baseline (T0), 1 wk (T1), and 4 wks (T2) after procedure. Mean Visual Analog Scale scores significantly dropped after the procedure (T0 = 6.2 [1.2]; T1 = 4.48 [1.5]; T2 = 4.32 [1.3]; T0 vs. T1 and P < 0.0001). A significant difference between preprocedure and postprocedure Western Ontario and McMaster Universities scores was found for pain (P < 0.0001) but not for joint stiffness (P = 0.7239) and disability (P = 0.6318). Ultrasonographic evaluation showed a significant reduction for both axial (P = 0.006) and sagittal (P = 0.01) areas of Baker's cyst, but no correlation was found between pain relief and Baker's cyst volume reduction. Cyst aspiration with corticosteroid injection give pain relief and cyst volume reduction in patients with Baker's cyst and concomitant knee osteoarthritis. However, when compared with current literature, our results are similar to those obtained with intra-articular knee corticosteroid injectio
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