2,031 research outputs found

    First results of systematic studies done with different types of Silicon Photomultipliers

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    The presented results are obtained during the first steps taken in order to develop a setup and measurement procedures which allow to compare properties of diverse kinds of silicon photomultipliers. The response to low-intensity light was studied for silicon photomultipliers produced by CPTA (Russia), Hamamatsu (Japan), ITC-irst (Italy) and SensL (Ireland).Comment: 3 pages, 3 figures, proceedings of the Internationa Linear Collider Workshop LCWS2007, Hamburg, German

    Low Cost NBTI Degradation Detection and Masking Approaches

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    Performance degradation of integrated circuits due to aging effects, such as Negative Bias Temperature Instability (NBTI), is becoming a great concern for current and future CMOS technology. In this paper, we propose two monitoring and masking approaches that detect late transitions due to NBTI degradation in the combinational part of critical data paths and guarantee the correctness of the provided output data by adapting the clock frequency. Compared to recently proposed alternative solutions, one of our approaches (denoted as Low Area and Power (LAP) approach) requires lower area overhead and lower, or comparable, power consumption, while exhibiting the same impact on system performance, while the other proposed approach (denoted as High Performance (HP) approach) allows us to reduce the impact on system performance, at the cost of some increase in area and power consumption

    Quality control facilities for large optical reflectors at ENEA-Casaccia for physics application

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    The paper describes the quality control facilities for large optical reflectors available at ENEA-Casaccia. Commercial and custom spectrophotometers allow to measure the reflectance; specular and diffused for flat samples, and specular for the full-size reflector. In the case of spherical shape, the 2f and the pin-hole optical tests give a quick evaluation of the focusing effectiveness and the curvature uniformity, respectively. An optical profilometer allows to accurately measure the reflector profile and its deviations from the project specifications

    First results of comparative studies of silicon photomultipliers

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    The presented results are obtained during the first steps taken in order to develop a set-up and measurement procedures which allow to compare properties of diverse samples of silicon photomultipliers. The response to low-intensity light was studied for silicon photomultipliers produced by CPTA (Russia), Hamamatsu(Japan), ITC-irst (Italy) and SensL (Ireland)

    Thermo-oxidative characterisation of the residues from persimmon harvest for its use in energy recovery processes

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    [EN] The residues from the harvest of persimmon fruit will be thermally valorised by means of high temperature reactions within a spouted bed reactor. With the aim to obtain valuable information for the design of the device, the thermo-chemical processes were simulated by multi-rate linear non-isothermal Thermogravimetric Analysis (TGA) using O-2 as carrier gas. In addition, a set of analyses were carried out using Ar as carrier gas in order to evaluate the influence of the atmosphere (oxidative or inert conditions) on the decomposition of the samples evaluating the reactions of pyrolysis. The release of gases was monitored by Evolved Gas Analysis (EGA) with in-line Fourier Transformed Infrared (FT-IR) analysis. The thermochemical reaction was mathematically described through the definition of the main kinetic parameters: activation energy (Ea), pre-exponential factor (In A) and model and order of reaction (n). The so-called kinetic triplet was calculated through the application of a methodology based on complementary isoconversional methods. These results will be the initial parameters that will help design the Spouted Bed Reactor and it is envisaged that they will be used in computer simulation software to achieve a better understanding of the process to obtain the optimum operational parameters. (C) 2016 Published by Elsevier B.V.Moliner, C.; Aguilar, A.; Bosio, B.; Arato, E.; Ribes-Greus, A. (2016). Thermo-oxidative characterisation of the residues from persimmon harvest for its use in energy recovery processes. Fuel Processing Technology. 152:421-429. https://doi.org/10.1016/j.fuproc.2016.07.008S42142915

    Chacarita Project: Conformation and analysis of a modern and documented human osteological collection from Buenos Aires City - Theoretical, methodological and ethical aspects

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    Osteological reference collections play a key role in bioanthropological research; they allow the development and testing of methods for sexing and aging individuals using different bone and dental attributes. This paper presents the first stage results of the ongoing Chacarita Research Project, which aims to generate and study a reference collection of adult skeletons representative of the contemporary population of Buenos Aires city. The Chacarita Collection is being conformed of unclaimed human remains of individuals of known nationality, sex, age, cause and date of death from the Chacarita Public Cemetery. Unlike other similar endeavors, this sample has been completely exhumed using archaeological techniques. So far, a total of 146 adult skeletons have been recovered (60 females - 41.1% - and 86 males - 58.90% -), the majority of which have ages-at-death in the range of 71-90 years. They were born primarily in Argentina (n = 133; 91.1%), although other nationalities are also represented. Dates of death go between 1987 and 2000. In the short term, the osteological study of this collection will allow assessment of the performance of classical methods of sex determination and age-at-death estimation in a local setting. A special priority will be given to the study of osteological changes in individuals over 50 years. As the sample is being retrieved by exhumation, the impact of taphonomic agents on the most diagnostic bones structures is also being assessed. In the long term, this osteological collection will be available to generate new population-specific techniques, and to develop comparative biological studies.Fil: Bosio, L. A.. Universidad de Buenos Aires. Facultad de Medicina. Cátedra de Medicina Legal y Deontología Médica. Servicio de Antropología Forense; ArgentinaFil: García Guraieb, S.. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; ArgentinaFil: Luna, Leandro Hernan. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Museo Etnográfico "Juan B. Ambrosetti"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aranda, C.. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Museo Etnográfico "Juan B. Ambrosetti"; Argentin

    A feasibility assessment of a retrofit Molten Carbonate Fuel Cell coal-fired plant for flue gas CO<sub>2</sub> segregation

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    This work considers the use of a Molten Carbonate Fuel Cell (MCFC) system as a power generation and CO2 concentrator unit downstream of the coal burner of an existing production plant. In this way, the capability of MCFCs for CO2 segregation, which today is studied primarily in reference to large-scale plants, is applied to an intermediate-size plant highlighting the potential for MCFC use as a low energy method of carbon capture. A technical feasibility analysis was performed using an MCFC system-integrated model capable of determining steady-state performance across varying feed composition. The MCFC user model was implemented in Aspen Custom Modeler and integrated into the reference plant in Aspen Plus. The model considers electrochemical, thermal, and mass balance effects to simulate cell electrical and CO2 segregation performance. Results obtained suggest a specific energy requirement of 1.41 MJ kg CO2 121 significantly lower than seen in conventional Monoethanolamine (MEA) capture processes

    Approach to a rational rotation number in a piecewise isometric system

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    We study a parametric family of piecewise rotations of the torus, in the limit in which the rotation number approaches the rational value 1/4. There is a region of positive measure where the discontinuity set becomes dense in the limit; we prove that in this region the area occupied by stable periodic orbits remains positive. The main device is the construction of an induced map on a domain with vanishing measure; this map is the product of two involutions, and each involution preserves all its atoms. Dynamically, the composition of these involutions represents linking together two sector maps; this dynamical system features an orderly array of stable periodic orbits having a smooth parameter dependence, plus irregular contributions which become negligible in the limit.Comment: LaTeX, 57 pages with 13 figure
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