Study and experimental test of Peltier cells for an energy recovery system in a renewable energy device

The present work focuses its attention about the need of implementation of an energy recovery system for a renewable energy device as photovoltaic cells. In a specific way the present paper is addressed to the evaluation of a potential use of Peltier cells to recover waste heat of PV, using the Seedback effect. An overview of Peltier cells, mainly focused on their functionality, properties and possible applications, is initially presented. The results of an extensive experimental test campaign is then presented; these tests have mainly been dedicated to the evaluation of Peltier cells properties in the electrical conversion of heating energy produced and/or not dissipated during the photovoltaic phenomena in siliceous PV cells. The last part of the work presents the results of a parallel test campaign where Peltier cells have been used as thermoelectric cooling devices, in the aim to improve the PV cell performance. In fact the efficiency and technical lifetime of these latter elements, is strongly affected by temperature of photovoltaic cell. This point and the dissipated heat are fundamental topics for every installation but above all in the cases of regions with a very hot climate or for concentrated photovoltaic plants

Vinyl Theory

Why are vinyl records making a comeback? How is their resurgence connected to the political economy of music? Vinyl Theory responds to these and other questions by exploring the intersection of vinyl records with critical theory. In the process, it asks how the political economy of music might be connected with the philosophy of the record. The young critical theorist and composer Theodor Adorno’s work on the philosophy of the record and the political economy of music of the contemporary French public intellectual, Jacques Attali, are brought together with the work of other theorists in order to understand the fall and resurrection of vinyl records. The major argument of Vinyl Theory is that the very existence of vinyl records may be central to understanding the resiliency of neoliberalism. This argument is made by examining the work of Adorno, Attali, Friedrich Nietzsche, and others on music through the lens of Michel Foucault’s biopolitics

Terror, Theory, and the Humanities

The events of September 11, 2001, have had a strong impact on theory and the humanities. They call for a new philosophy, as the old philosophy is inadequate to account for them. They also call for reflection on theory, philosophy, and the humanities in general. While the recent location and killing of Osama bin Laden, the leader of al-Qaeda, in Pakistan on May 2, 2011 - almost ten years after he and his confederates carried out the 9/11 attacks - may have ended the "war on terror", it has not ended the journey to understand what it means to be a theorist in the age of phobos nor the effort to create a new philosophy that measures up with life in the new millennium. It is in the spirit of hope - the hope that theory will help us to understand the age of terror - that the essays in this collection are presented

Metrological Characterization of a Vision-Based Measurement System for the Online Inspection of Automotive Rubber Profile

This paper deals with the metrological characterization of a stereovision-based measurement system for the inspection of automotive rubber profiles in an industrial plant. The characterization of this class of measurement systems introduces new challenges due to both the unavailability of reference measurement instruments and the complexity of the measurement system itself, which does not allow a straightforward application of the standard procedures for uncertainty evaluation. To assign optimum values to a number of design parameters, the followed approach focuses not only on evaluating the total uncertainty but also on analyzing systematic effects and influence quantities

A New Calibration Procedure for 3-D Shape Measurement System Based on Phase-Shifting Projected Fringe Profilometry

An original procedure is presented for the calibration of fringe-projection-based 3-D vision systems. The proposed approach estimates both the phase-to-depth and transverse relationships by directly measuring the phase maps for only three planes placed within the calibration volume and then estimating the phase maps for a number of other ldquovirtual planes.rdquo Experimental tests conducted on a fringe projection system show the effectiveness of the proposed procedure

Liver fibrosis in primary intestinal lymphangiectasia: an undervalued topic

The relationship between primary intestinal lymphangiectasia (PIL) and liver fibrosis is an emerging topic with many obscure aspects due to the rarity of the disorder. A recent paper reported that a six-month lowfat diet improved liver fibrosis. We report the case of a 17-year-old girl affected by PIL whose hepatic fibrosis progressively worsened within one year, despite dietetic support. This and the previous case report describe extraordinary events, which do not allow clear-cut clinical aspects to be established. Nevertheless, both cases suggest that in patients with PIL, it is necessary to closely monitor liver morphology with in-depth investigations including not only ultrasonography, but also elastography

Structure of Turbulence in Katabatic Flows below and above the Wind-Speed Maximum

Measurements of small-scale turbulence made over the complex-terrain atmospheric boundary layer during the MATERHORN Program are used to describe the structure of turbulence in katabatic flows. Turbulent and mean meteorological data were continuously measured at multiple levels at four towers deployed along the East lower slope (2-4 deg) of Granite Mountain. The multi-level observations made during a 30-day long MATERHORN-Fall field campaign in September-October 2012 allowed studying of temporal and spatial structure of katabatic flows in detail, and herein we report turbulence and their variations in katabatic winds. Observed vertical profiles show steep gradients near the surface, but in the layer above the slope jet the vertical variability is smaller. It is found that the vertical (normal to the slope) momentum flux and horizontal (along the slope) heat flux in a slope-following coordinate system change their sign below and above the wind maximum of a katabatic flow. The vertical momentum flux is directed downward (upward) whereas the horizontal heat flux is downslope (upslope) below (above) the wind maximum. Our study therefore suggests that the position of the jet-speed maximum can be obtained by linear interpolation between positive and negative values of the momentum flux (or the horizontal heat flux) to derive the height where flux becomes zero. It is shown that the standard deviations of all wind speed components (therefore the turbulent kinetic energy) and the dissipation rate of turbulent kinetic energy have a local minimum, whereas the standard deviation of air temperature has an absolute maximum at the height of wind-speed maximum. We report several cases where the vertical and horizontal heat fluxes are compensated. Turbulence above the wind-speed maximum is decoupled from the surface, and follows the classical local z-less predictions for stably stratified boundary layer.Comment: Manuscript submitted to Boundary-Layer Meteorology (05 December 2014

Youth itineraries, individuation, and reflexivities: approaches to social participation in low-income metropolitan neighborhoods

En este artículo se presenta un análisis de itinerarios de individuación, en atención a las formas de participación y reflexividad de personas jóvenes que viven en barrios populares de tres áreas metropolitanas: Buenos Aires/Argentina, Porto Alegre/Brasil y Santiago/Chile. Para ello, se articulan resultados de diferentes estudios empíricos desarrollados entre 2013 y 2019, con herramientas conceptuales de la sociología del individuo de Danilo Martuccelli, especialmente las nociones de pruebas, soportes y texturas sociales. En primer lugar, se abordan los referentes teóricos utilizados para el despliegue del problema y las estrategias metodológicas utilizadas para la construcción y el análisis de las narrativas juveniles. Posteriormente, se realiza la interpretación del corpus de datos en torno a dos ejes centrales: a) territorios, actores e intermundos populares; b) jóvenes, participación social y reflexividades. Las personas jóvenes enfrentan, en diversos territorios populares, una pluralidad de coerciones materiales y simbólicas. Sin embargo, allí también traman espacios colectivos donde establecen identificaciones personales y grupales, cuando descubren o generan propuestas deportivas, artístico-políticas y educativas. En estas, producen vínculos intergeneracionales, recuperan saberes ancestrales y construyen marcos referenciales y reflexivos, volviendo la territorialidad un soporte y un signo de reconocimiento. En este sentido, el estudio de las narrativas juveniles constituye una herramienta privilegiada para el análisis de las agencias y las individualidades populares latinoamericanas.This study analyzes individuation itineraries by considering the forms of participation and reflexivity of young people who live in low-income neighborhoods in three metropolitan areas: Buenos Aires/Argentina, Porto Alegre/Brazil, and Santiago/Chile. For this, this study articulated the results of several empirical studies conducted from 2013 to 2019 with the conceptual tools in Danilo Martuccelli’s sociology of the individual, especially its notions of tests, supports, and social textures. This research first addresses theoretical frameworks to implement its problem and methodological strategies to build and analyze youth’s narratives. Then, it interpreted its data corpus around two central axes: a) low-income territories, actors, and interworlds and b) young people, social participation, and reflexivities. Young people face a plurality of material and symbolic coercions in several low-income territories. However, these territories also create collective spaces in which youths establish personal and group identifications as they discover or generate sports, artistic-political, and educational proposals, which create intergenerational bonds, recover ancestral knowledge, and build referential and reflective landmarks, transforming territorialities into supports and a sign of recognition. Thus, studying youth narratives offers a privileged tool to analyze Latin American low-income agencies and individualities

In Situ Lithiation–Delithiation of Mechanically Robust Cu–Si Core–Shell Nanolattices in a Scanning Electron Microscope

Nanoarchitected Cu–Si core–shell lattices were fabricated via two-photon lithography and tested as mechanically robust Li-ion battery electrodes which accommodate ∼250% Si volume expansion during lithiation. The superior mechanical performance of the nanolattice electrodes is directly observed using an in situ scanning electron microscope, which allows volume expansion and morphological changes to be imaged at multiple length scales, from single lattice beam to the architecture level, during electrochemical testing. Finite element modeling of lithiation-induced volume expansion in a core–shell structure reveals that geometry and plasticity mechanisms play a critical role in preventing damage in the nanolattice electrodes. The two-photon lithography-based fabrication method combined with computational modeling and in situ characterization capabilities would potentially enable the rational design and fast discovery of mechanically robust and kinetically agile electrode materials that independently optimize geometry, feature size, porosity, surface area, and chemical composition, as well as other functional devices in which mechanical and transport phenomena are important

Variational Field Theoretic Approach to Relativistic Scattering

Nonperturbative polaron variational methods are applied, within the so-called particle or worldline representation of relativistic field theory, to study scattering in the context of the scalar Wick - Cutkosky model. Important features of the variational calculation are that it is a controlled approximation scheme valid for arbitrary coupling strengths, the Green functions have all the cuts and poles expected for the exact result at any order in perturbation theory and that the variational parameters are simultaneously sensitive to the infrared as well as the ultraviolet behaviour of the theory. We generalize the previously used quadratic trial action by allowing more freedom for off-shell propagation without a change in the on-shell variational equations and evaluate the scattering amplitude at first order in the variational scheme. Particular attention is paid to the $s$-channel scattering near threshold because here non-perturbative effects can be large. We check the unitarity of a our numerical calculation and find it greatly improved compared to perturbation theory and to the zeroth order variational results.Comment: 26 pages, Latex, 5 postscript figures embedded with epsf, submitted to Nucl. Phys.