238 research outputs found
DISRUPTIVE TECHNOLOGIES OF GENERATION DISTRIBUTED AND ITS FUTURE IMPACTS ON ENERGY COMPANIES DOI: 10.5585/rai.v6i1.284
This paper develops a forecast of the future impact of disruptive technologies for distributed generation on the distribution of electric energy, with use of scenarios. Distributed generation (DG) is defined by the power generation technologies for which production is intended primarily to serve local loads, and disruptive technologies are considered those that, in general, cannot be easily evaluated by a dominant company, but when it is discovered by consumers, the firm changes the initial characteristics of the market and are rapidly incorporated by new consumers and producers. To accomplish the paper, it was used a methodology for the elaboration of scenarios from the use of combined techniques such as Delphi, quantitative extrapolation of data, Analysis and Structuring of Models (AEM) and evaluation of impacts. The results indicate that, with the advent of distributed generation, it will be possible to mitigate any eventual effects of uncertainty on the demand for energy. Thus, as a consequence of less uncertainty in supply, the introduction of distributed generation can contribute with the reliability and efficiency of the system more.Este trabalho faz uma previsão, a partir da construção de cenários, do impacto futuro de tecnologias disruptivas de geração distribuída sobre a distribuição de energia elétrica. Geração Distribuída (GD) é definida por tecnologias de geração de energia cuja produção é destinada a atender predominantemente cargas locais, e tecnologias disruptivas são consideradas aquelas que, em geral, não podem ser facilmente avaliadas por uma empresa dominante, mas, ao serem descobertas pelos consumidores, alteram as características iniciais do mercado e são incorporadas rapidamente por consumidores e novos produtores. Para a realização do trabalho, foi utilizada uma metodologia de elaboração de cenários a partir do uso de técnicas combinadas, como Delphi, extrapolações de dados, Análise e Estruturação de Modelos (AEM) e avaliação de impactos. Os resultados indicam que, com o advento da geração distribuída, será possível mitigar eventuais efeitos da incerteza da demanda de energia. Assim, como consequência da menor incerteza na oferta, a introdução da geração distribuída pode contribuir para tornar o sistema mais confiável e eficiente
Beta-decay branching ratios of 62Ga
Beta-decay branching ratios of 62Ga have been measured at the IGISOL facility
of the Accelerator Laboratory of the University of Jyvaskyla. 62Ga is one of
the heavier Tz = 0, 0+ -> 0+ beta-emitting nuclides used to determine the
vector coupling constant of the weak interaction and the Vud quark-mixing
matrix element. For part of the experimental studies presented here, the
JYFLTRAP facility has been employed to prepare isotopically pure beams of 62Ga.
The branching ratio obtained, BR= 99.893(24)%, for the super-allowed branch is
in agreement with previous measurements and allows to determine the ft value
and the universal Ft value for the super-allowed beta decay of 62Ga
Q-value of the superallowed beta decay of Ga-62
Masses of the radioactive isotopes 62Ga, 62Zn and 62Cu have been measured at
the JYFLTRAP facility with a relative precision of better than 18 ppb. A Q_EC
value of (9181.07 +- 0.54) keV for the superallowed decay of 62Ga is obtained
from the measured cyclotron frequency ratios of 62Ga-62Zn, 62Ga-62Ni and
62Zn-62Ni ions. The resulting Ft-value supports the validity of the conserved
vector current hypothesis (CVC). The mass excess values measured were (-51986.5
+-1.0) keV for 62Ga, (-61167.9 +- 0.9) keV for 62Zn and (-62787.2 +- 0.9) keV
for 62Cu.Comment: 12 pages, 3 figures, 2 tables, submitted to Phys. Lett. B. v2: added
acknowledgement
Spectroscopy of Na: Bridging the two-proton radioactivity of Mg
The unbound nucleus Na, the intermediate nucleus in the two-proton
radioactivity of Mg, was studied by the measurement of the resonant
elastic scattering reaction Ne(p,Ne)p performed at 4 A.MeV.
Spectroscopic properties of the low-lying states were obtained in a R-matrix
analysis of the excitation function. Using these new results, we show that the
lifetime of the Mg radioactivity can be understood assuming a sequential
emission of two protons via low energy tails of Na resonances
Accuracy of right atrial pressure estimation using a multi-parameter approach derived from inferior vena cava semi-automated edge-tracking echocardiography: a pilot study in patients with cardiovascular disorders
The echocardiographic estimation of right atrial pressure (RAP) is based on the size and inspiratory collapse of the inferior vena cava (IVC). However, this method has proven to have limits of reliability. The aim of this study is to assess feasibility and accuracy of a new semi-automated approach to estimate RAP. Standard acquired echocardiographic images were processed with a semi-automated technique. Indexes related to the collapsibility of the vessel during inspiration (Caval Index, CI) and new indexes of pulsatility, obtained considering only the stimulation due to either respiration (Respiratory Caval Index, RCI) or heartbeats (Cardiac Caval Index, CCI) were derived. Binary Tree Models (BTM) were then developed to estimate either 3 or 5 RAP classes (BTM3 and BTM5) using indexes estimated by the semi-automated technique. These BTMs were compared with two standard estimation (SE) echocardiographic methods, indicated as A and B, distinguishing among 3 and 5 RAP classes, respectively. Direct RAP measurements obtained during a right heart catheterization (RHC) were used as reference. 62 consecutive \u2018all-comers\u2019 patients that had a RHC were enrolled; 13 patients were excluded for technical reasons. Therefore 49 patients were included in this study (mean age 62.2\ua0\ub1\ua015.2\ua0years, 75.5% pulmonary hypertension, 34.7% severe left ventricular dysfunction and 51% right ventricular dysfunction). The SE methods showed poor accuracy for RAP estimation (method A: misclassification error, ME\ua0=\ua051%, R2\ua0=\ua00.22; method B: ME\ua0=\ua069%, R2\ua0=\ua00.26). Instead, the new semi-automated methods BTM3 and BTM5 have higher accuracy (ME\ua0=\ua014%, R2\ua0=\ua00.47 and ME\ua0=\ua022%, R2\ua0=\ua00.61, respectively). In conclusion, a multi-parametric approach using IVC indexes extracted by the semi-automated approach is a promising tool for a more accurate estimation of RAP
Direct and sequential radiative three-body reaction rates at low temperatures
We investigate the low-temperature reaction rates for radiative capture
processes of three particles. We compare direct and sequential capture
mechanisms and rates using realistic phenomenological parametrizations of the
corresponding photodissociation cross sections.Energy conservation prohibits
sequential capture for energies smaller than that of the intermediate two-body
structure. A finite width or a finite temperature allows this capture
mechanism. We study generic effects of positions and widths of two- and
three-body resonances for very low temperatures. We focus on nuclear reactions
relevant for astrophysics, and we illustrate with realistic estimates for the
-- and -- radiative capture
processes. The direct capture mechanism leads to reaction rates which for
temperatures smaller than 0.1 GK can be several orders of magnitude larger than
those of the NACRE compilation.Comment: To be published in European Physical Journal
High-precision half-life and branching-ratio measurements for superallowed Fermi β \u3csup\u3e+\u3c/sup\u3e emitters at TRIUMF - ISAC
A program of high-precision half-life and branching-ratio measurements for superallowed Fermi β emitters is being carried out at TRIUMF\u27s Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. Recent half-life measurements for the superallowed decays of 14O, 18Ne, and 26Alm, as well as branching-ratio measurements for 26Alm and 74Rb are reported. These results provide demanding tests of the Standard Model and the theoretical isospin symmetry breaking (ISB) corrections in superallowed Fermi β decays. © Owned by the authors, published by EDP Sciences, 2014
β-delayed γ-proton decay in 56Zn: analysis of the charged-particle spectrum
A study of the beta decay of the proton-rich T-z = 2 nucleus Zn-56 has been reported in a recent publication. A rare and exotic decay mode, beta-delayed gamma-proton decay, has been observed there for the first time in the fp shell. Here, we expand on some of the details of the data analysis, focussing on the charged particle spectrum
Beta decay of the Tz=-2 nucleus 64Se and its descendants
International audience; The beta decay of the Tz=-2 nucleus 64Se has been studied in a fragmentation reaction at RIKEN-Nishina Center. 64Se is the heavies Tz=-2 nucleus that decays to bound states in the daughter nucleus and the heaviest case where the mirror reaction 64Zn(3He,t)64Ga on the Tz=+2 64Zn stable target exists and can be compared. Beta-delayed gamma and proton radiation is reported for the 64Se and 64As cases. New levels have been observed in 64As, 64Ge (N=Z), 63Ge and 63Ga. The associated T1/2 values have been obtained
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