Extreme lower probabilities

We consider lower probabilities on finite possibility spaces as models for the uncertainty about the state. These generalizations of classical probabilities can have some interesting properties; for example: k-monotonicity, avoiding sure loss, coherence, permutation invariance. The sets formed by all the lower probabilities satisfying zero or more of these properties are convex. We show how the extreme points and rays of these sets ─ the extreme lower probabilities ─ can be calculated and we give an illustration of our results

A focus on selected perspectives of the NUMEN project

The use of double charge exchange reactions is discussed in view of their application to extract information that may be helpful to determinate the nuclear matrix elements entering in the expression of neutrinoless double beta decay half-life. The strategy adopted in the experimental campaigns performed at INFN - Laboratori Nazionali del Sud and in the analysis methods within the NUMEN project is briefly described, emphasizing the advantages of the multi-channel approach to nuclear reaction data analysis. An overview on the research and development activities on the MAGNEX magnetic spectrometer is also given, with a focus on the chosen technological solutions for the focal plane detector which will guarantee the performances at high-rate conditions

Transient current effects on poly(o-methoxyaniline) films irradiated by pulsed electron beam

Fast transient current decay was recorded on POMA samples during current pulses (in the order of milliseconds) provided by a low energy electron beam under an applied field. The characteristic time decay depends on the electron beam energy and on the bias polarity. The results were explained taking into account the effect of space charge, the intrinsic conductivity of the non-irradiated region of the sample and the radiation-induced conductivity of the thin irradiated region. Fitting parameters may provide the value of both intrinsic and radiation-induced conductivities and the average electron range

Using shifts in the electronic emission curve to evaluate polymer surface degradation

The polymer surface degradation and/or modification evolution of Teflon FEP and Mylar C films caused by a low energy electron beam were analyzed using a new method that consists in measuring the second crossover energy shift in the electronic emission curve. Upon prolonged irradiation, the second crossover energy shifts irreversibly to lower values in Teflon FEP but to higher values in Mylar C, indicating distinct mechanisms of surface degradation for the two polymers. The method represents a relatively inexpensive way to monitor early stages of surface degradation since the secondary electron emission comes from a maximum depth below the geometric surface of 100 mn in insulators. (C) 2001 Elsevier B.V. Ltd. All rights reserved

Effects of flunitrazepam on local cerebral glucose utilization in the rat brain.

Flunitrazepam effects on local cerebral glucose utilization in the rat brain were investigated with the (14C) 2-Deoxy-D-Glucose procedure. The drug decreased glucose utilization in many areas of the rat brain, whereas no increases were observed. In this respect, the metabolic effects of flunitrazepam were different from those of other CNS "depressant" drugs, such as isoflurane and phencyclidine. Compared to the metabolic changes induced by diazepam, flunitrazepam peak effects appeared later and involved a greater number of regions

Compression waves and kinetic energy losses in collisions between balls and rods of different lengths

We report investigations of collisions between steel balls and free-ended rods using an electro-mechanical apparatus combined with a Michelson interferometer. Our experimental methodology allows for the evaluation of several collision-initiated parameters, such as collision duration, speed of the inter-material wave pulse, change in rod length, and post-collision center-of-mass velocity. The fractional loss of kinetic energy of the ball-rod system is studied theoretically and experimentally as a function of the rod length. Results are compared to predictions obtained from the elastic-body collision theory. Several aspects of elastic waves are illustrated without recourse to complicated mathematics. The experiment provides significant insight into the physical behavior of colliding solids. (C) 2014 American Association of Physics Teachers.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Espectroscopia de impedância no laboratório de ensino

Neste trabalho, mostramos que uma configuração desconhecida de um circuito montado com resistores e capacitores no interior de uma caixa preta, pode ser determinada através de uma técnica, conhecida como espectroscopia de impedância, largamente utilizada em várias areas da ciência. Como essa técnica faz uso da impedância complexa, apresentamos também uma introdução aos circuitos AC do ponto de vista do formalismo de números complexos. O arranjo experimental utiliza um gerador de audio como fonte AC para alimentar a caixa e um osciloscópio de duplo canal para medir tanto a parte real como a imaginária da impedância complexa do circuito desconhecido em função da frequência do gerador. A partir do espectro de impedância obtido, identifica-se não só a configuração do circuito no interior da caixa como também os valores das resistências e capacitâncias utilizadas para montá-lo.In this work we show that the configuration of an electrical circuit made up of resistors and capacitors in a black box may be determined using impedance spectroscopy, a technique that has been largely used in several scientific areas. Because the complex impedance is measured in this technique, we present basic concepts of a.c. electrical circuits analyzed with the formalism of complex numbers. The experimental setup includes a radiofrequency generator as the a.c. source for the circuit and a double-channel oscilloscope to measure both the real and imaginary parts of the complex impedance of the circuit in the black box. From the impedance spectrum we can not only determine the configuration of the electrical circuit in the black box but also the values of resistors and capacitors used.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Surface modifications on Teflon FEP and Mylar C induced by a low energy electron beam: a Raman and FTIR spectroscopic study

The surface modifications induced on Teflon FEP and Mylar C polymer films by a low energy electron beam are probed using Raman and FTIR spectroscopy. The electron beam, which does not affect the Mylar C, surface, may break the copolymer chain into its monomers degrading the Teflon FEP surface. For Mylar C the electron beam decreases the roughness of the polymer surface. This difference in behavior may explain recent results in which the surface modifications investigated by measuring the second crossover energy shift in the electronic emission curve differed for the two polymers (Chinaglia et al [1]). In addition, the Raman data showed no evidence of carbon formation for either polymer samples, which is explained by the fact that only a low energy electron beam is used

Biodegradation of the Films of PP, PHBV and Its Blend in Soil

Films of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(propylene) (PP), PP/PHBV (4:1), blends were prepared by melt-pressing and investigated with respect to their microbial degradation in soil after 120 days. Biodegradation of the films was evaluated by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction. The biodegradation and/or bioerosion of the PP/PHBV blend was attributed to microbiological attack, with major changes occurring at the interphases of the homopolymers. The PHBV film was more strongly biodegraded in soil, decomposing completely in 30 days, while PP film presented changes in amorphous and interface phase, which affected the morphology

Contribution of an extrinsic mechanism for the electrical polarization in BiMn2O5 ceramics

DC conductivity, frequency dependent dielectric constant and pyroelectric coefficients, obtained from thermal stimulated depolarization current curves, in BiMn2O5 ceramics in the range of temperatures from 10 K to 320 K are reported. The data could be explained if it is assumed that a dipole defect is formed due to an oxygen vacancy and two manganese ions which have their valence changed to accept an electron. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi.org/10.1063/1.4769752]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES