Search results for "Scheme"

QRPA estimate for the Δ (1232) contribution to the Gamow-Teller decay of heavy nuclei

1991

Abstract The contribution of the Δ (1232) isobars to the nuclear beta decay strength function is estimated in the framework of the charge-changing form of the QRPA. This procedure is applied to neutron-deficient tin isotopes. The results imply that the quenching of the low-energy Gamow-Teller decay strength cannot attributed to the presence of delta admixtures in the nuclear wave function.

Numerical expressions for the computation of coincidence-summing correction factors in γ-ray spectrometry with HPGe detectors

2009

Numerical expressions to compute gamma-gamma and gamma-X(K) coincidence summing corrections were deduced by using a suitable computer program and a matrix representation of a decay scheme. For point sources only full-energy peak and total efficiencies are needed. Alternatively, values of peak-to-total ratio can be introduced. For extended sources, the same expressions can be considered with the introduction of "effective efficiencies". Examples of the use of the expressions for point sources and a particulate filter sample measured with a 60% relative efficiency HPGe detector are reported.

A particle method for a Lotka-Volterra system with nonlinear cross and self-diffusion

2008

Semistable Higgs bundles, periodic Higgs bundles and representations of algebraic fundamental groups

2019

Let $k $ be the algebraic closure of a finite field of odd characteristic $p$ and $X$ a smooth projective scheme over the Witt ring $W(k)$ which is geometrically connected in characteristic zero. We introduce the notion of Higgs-de Rham flow and prove that the category of periodic Higgs-de Rham flows over $X/W(k)$ is equivalent to the category of Fontaine modules, hence further equivalent to the category of crystalline representations of the \'{e}tale fundamental group $\pi_1(X_K)$ of the generic fiber of $X$, after Fontaine-Laffaille and Faltings. Moreover, we prove that every semistable Higgs bundle over the special fiber $X_k$ of $X$ of rank $\leq p$ initiates a semistable Higgs-de Rham …

Distributed routing and channel allocation in multi-channel multi-hop ad hoc networks

2013

In this paper, we propose a novel routing protocol which is integrated with channel assignment for multi-channel multi-hop wireless ad hoc networks. In such a network, each node is equipped with three transceivers. One is always tuned on a control channel which is responsible for control and broadcast messages, and the other two perform as transmitter and receiver respectively for traffic flows on different data channels. The routing protocol works in an on-demand manner, and the proposed routing discovery process selects a path that potentially traverses nodes with lighter traffic load and lower number of carried flows. With a given number of non-overlapping channels, the optimal solution …

A mini-slot-based cooperative MAC protocol for wireless mesh networks

2010

This paper proposes a TDMA-based medium access control protocol with cooperative communications enabled in wireless mesh networks. The proposed scheme is based on a multi-hop scenario which is extended from the conventional one-hop triangle cooperative transmission scenario. Benefiting from the elaborate mini-slot design, channel resources are fairly and efficiently allocated to each router so that no handshake is needed prior to every packet transmission. By giving priority for channel access to cooperative transmission performed by an optimal helper which is determined based on the received SNR, higher successful transmission rate can be achieved. Numerical results demonstrate that the pr…

The effect of support schemes on Photovoltaic installed capacity in Europe: a WDEA-STATIS analysis

2014

The European Union (EU) has been committed to promoting Renewable Energy Sources (RES) since 1985, focusing its attention on the financial coordination needed to support the sector, and the possibility of harmonizing support scheme systems. Starting from this assumption, the aim of this study is to provide, by means of STATIS together with windows DEA analysis, a response about which kind of support schemes have worked best in a sample of 11 EU Member States over the last 15 years in terms of Photovoltaic overall installed capacity, the most expensive RES technology.

Geostatistic study of salt distribution in “laguna de Salinas”. Alicante. Spain

1999

The distribution of different types of salts and the dynamic processes leading to their distribution in a playa saltlake of 3x2 Km wide, were drawn using statistics and geostatistics of the data obtained by augering the soil at different depths, following a regular square grid sampling scheme. The lake is now colonised by Halophytes which density corresponds inversely with the salinity gradient, although the main surface of the lake remains bare.

Postprocessing of a Finite Element Scheme with Linear Elements

1987

In this contribution we first give a brief survey of postprocessing techniques for accelerating the convergence of finite element schemes for elliptic problems. We also generalize a local superconvergence technique recently analyzed by Křižek and Neittaanmaki ([20]) to a global technique. Finally, we show that it is possible to obtain O(h4) accuracy for the gradient in some cases when only linear elements are used. Numerical tests are presented.

FLEX End-to-End Mission Performance Simulator

2016

The FLuorescence EXplorer (FLEX) mission, selected as the European Space Agency's eighth Earth Explorer, aims to globally measure the sun-induced-chlorophyll-fluorescence spectral emission from terrestrial vegetation. In the frame of the FLEX mission, several industrial and scientific studies have analyzed the instrument design, image processing algorithms, or modeling aspects. At the same time, a common tool is needed to address the overall FLEX mission performance by combining all these features. For this reason, an end-to-end mission performance simulator has been developed for the FLEX mission (FLEX-E). This paper describes the FLEX-E software design, which combines the generation of co…