Low-energy structure of the even-A 96−104 Ru isotopes via g-factor measurements

The transient-field-perturbed angular correlation technique was used with Coulomb excitation in inverse kinematics to perform a systematic measurement of the g factors of the first excited 21+ states in the stable even-A isotopes Ru96-104. The measurements have been made relative to one another under matched kinematic conditions and include a measurement of g(21+)=+0.47(3) in Ru96

Enhanced Mixing of Intrinsic States in Deformed Hf Nuclei

Excited low-spin, nonyrast states in 170,172,174Hf were populated in β + /∈decay and studied through off-beam γ-ray spectroscopy. New coincidence data allowed for a substantial revision of the level schemes of Hf170,172 and a confirmation of the level scheme of 174Hf. The Hf isotopes represent a unique situation in which a crossing of collective intrinsic excitations occurs, enhancing significantly the effects of mixing. Using branching ratios from excited 2+ states, this mixing is followed and studied. The resulting mixing matrix elements are found to be ∼30 keV—an order of magnitude larger than estimated previously for nearby nuclei. In the case of 170Hf, the 2+β and 2+γlevel are shown to be completely mixed

Cálculo de forças magnéticas e tensões mecânicas por elementos finitos em estruturas com ímãs permanentes: aplicação à máquina de fluxo axial

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2020.As propriedades magnéticas e elásticas são, geralmente, fortemente relacionadas em materiais magnéticos. Esse comportamento acoplado tem consequências sobre a modelagem e o cálculo de forças e tensões mecânicas de origem magnética em dispositivos eletromagnéticos. Por meio da aplicação do princípio das potências virtuais e conceitos de mecânica dos meios contínuos, diversas expressões do tensor de Maxwell são obtidas baseadas em simples modelos matemáticos do comportamento da magnetização em relação à deformação. Em particular, a modelagem de ímãs permanentes, que não se tem um consenso na literatura, é analisada em detalhe. Uma máquina de fluxo axial com ímãs permanentes é simulada em um software de elementos finitos por meio de uma formulação magnetostática, de forma que os campos resultantes são utilizados para o cálculo de forças locais, aplicando os modelos de tensor de Maxwell, considerando um acoplamento magnetoelástico parcial, ou seja, o efeito das tensões mecânicas sobre o comportamento magnético é desprezado. A metodologia e as análises apresentadas podem ser úteis para o cálculo de grandezas mecânicas, como tensões mecânicas induzidas por forças magnéticas, de forma a auxiliar no projeto de dispositivos eletromagnéticos.Abstract: Magnetic and elastic properties are, generally, strongly related in magnetic materials. This coupled behavior has consequences on the modeling and calculation of magnetic forces and resulting stress in electromagnetic devices. Through the application of the virtual power principle and concepts of continuum mechanics, several expressions of Maxwell stress tensor are obtained based on mathematical models that describe the relation between magnetization and deformation. In particular, the modeling of permanent magnets, which does not have a consensus in the literature, is analyzed in detail. An axial flux permanent magnet machine is simulated in a finite element software by application of a magnetostatics formulation, so that the resulting magnetic fields are used to calculate local forces, applying Maxwell stress tensor models, considering a partial magnetoelastic coupling, that is, the effects of stresses on magnetic behavior are ignored. The methodology and analyses presented can be useful to the calculation of mechanical quantities, such as stresses induced by magnetic forces, in order to help the design of electromagnetic devices

Modelagem da Histerese Magnética em Materiais Magnéticos Utilizando o Modelo de Jiles-Atherton

Magnetic materials are used in electrical machines, power transformers,inductors and others magnetic devices. These devices present nonlinearbehaviour which difficult magnetic field and flux calculations. The Jiles-Atherton model, based in experimental measurements, is used to represent thenonlinear behaviour in magnetic materials. In this work, this model is appliedin a monofasic transformer

Atmospheric Nitrogen Deposition in South–East Scotland: Quantification of the Organic Nitrogen Fraction in Wet, Dry and Bulk Deposition

Water soluble organic nitrogen (WSON) compounds are ubiquitous in precipitation and in the planetary boundary layer, and therefore are a potential source of bioavailable reactive nitrogen. This paper examines weekly rain data over a period of 22 months from June 2005 to March 2007 collected in 2 types of rain collector (bulk deposition and “dry+wet” deposition) located in a semi-rural area 15 km southwest of Edinburgh, UK (N 555144″, W 31219″). Bulk deposition collectors are denoted in this paper as “standard rain gauges”, and they are the design used in the UK national network for monitoring precipitation composition. “Dry+wet” deposition collectors are flushing rain gauges and they are equipped with a rain detector (conductivity array), a spray nozzle, a 2-way valve and two independent bottles to collect funnel washings (dry deposition) and true wet deposition. On average, for the 27 weekly samples with 3 valid replicates for the 2 types of collectors, dissolved organic nitrogen (DON) represented 23% of the total dissolved nitrogen (TDN) in bulk deposition. Dry deposition of particles and gas on the funnel surface, rather than rain, contributed over half of all N-containing species (inorganic and organic). Some discrepancies were found between bulk rain gauges and flushing rain gauges, for deposition of both TDN and DON, suggesting biological conversion and loss of inorganic N in the flushing samplers

First experimental test of X(5) critical-point symmetry in the A ∼ 130 mass region: Low-spin states and the collective structure of 130 Ce

Excited, low-spin states in Ce130 are populated in the ?+/? decay of Pr130 and studied through off-beam ?-ray spectroscopy at the Yale moving tape collector. New coincidence data lead to the construction of a substantially revised level scheme. The low-lying states of Ce130 are compared with the predictions of the X(5) critical-point model and the X(5)-?4 model, and the latter is found to give better agreement with the data in terms of energies. Discrepancies in the relative B(E2) values in Ce130 and the geometrical models suggest that the ? degree of freedom may play an important role in this mass region. � 2008 The American Physical Society

Centrifugal stretching from lifetime measurements in the 170 Hf ground state band

Centrifugal stretching in the deformed rare-earth nucleus 170Hf is investigated using high-precision lifetime measurements, performed with the New Yale Plunger Device at Wright Nuclear Structure Laboratory, Yale University. Excited states were populated in the fusion-evaporation reaction 124Sn(50Ti,4n)170Hf at a beam energy of 195 MeV. Recoil distance doppler shift data were recorded for the ground state band through the J=16+ level. The measured B(E2) values and transition quadrupole moments improve on existing data and show increasing ? deformation in the ground state band of 170Hf. The results are compared to descriptions by a rigid rotor and by the confined ?-soft rotor model. � 2013 American Physical Society