Tunable asymmetric magnetoimpedance effect in ferromagnetic NiFe/Cu/Co films

We investigate the magnetization dynamics through the magnetoimpedance effect in ferromagnetic NiFe/Cu/Co films. We observe that the magnetoimpedance response is dependent on the thickness of the non-magnetic Cu spacer material, a fact associated to the kind of the magnetic interaction between the ferromagnetic layers. Thus, we present an experimental study on asymmetric magnetoimpedance in ferromagnetic films with biphase magnetic behavior and explore the possibility of tuning the linear region of the magnetoimpedance curves around zero magnetic field by varying the thickness of the non-magnetic spacer material, and probe current frequency. We discuss the experimental magnetoimpedance results in terms of the different mechanisms governing the magnetization dynamics at distinct frequency ranges, quasi-static magnetic properties, thickness of the non-magnetic spacer material, and the kind of the magnetic interaction between the ferromagnetic layers. The results place ferromagnetic films with biphase magnetic behavior exhibiting asymmetric magnetoimpedance effect as a very attractive candidate for application as probe element in the development of auto-biased linear magnetic field sensors.Comment: 5 figure

ON THE MONITORING OF THE GAS-SOLID FLOWS IN INDUSTRIAL FLUIDIZED BEDS BY USING ELECTRICAL CHARGE SENSORS

The fluidized bed technology has been used in many industrial processes. It promotes good rates of heat, mass transfer and chemical reaction by generating high level of gas-solid mixture. However, the assurance of quality and efficiency of these processes requires the monitoring of the gas-solid flow. For this propose, there are some sensing techniques that allows generating dynamic signals from cold or hot fluidized beds. They are based on pressure fluctuations, acoustic and mechanical vibrations, electrical capacitance and on electrical charges. Electrical charge sensors were proposed originally for measuring the flow velocity in pneumatic conveying. They are composed of one or more metallic electrodes that detect electrical charges in the gas-solid flow, which are generated by particle-particle and particle-wall interaction due to triboelectric effect. In this work, such sensors are explored as a robust and inexpensive solution for the monitoring of industrial fluidized beds. However, since research investments are requested specially on the design of the sensor, concerning the flow quantity of interest and the electrification processes acting on the sensor, in this work different configurations were classified from information in literature, and other were proposed in this work concerning their use with industrial fluidized beds. Although the relation between magnitude of the detected charges and some physical quantities of the flow, such as concentration, is still not clear, other important information can be obtained by analyzing dynamic signals, as velocity or bubbles frequency, or even for identifying of the fluidization regime. It was stated that each configuration, with its own shape and arrangement, can promote or not one or other electrification process by contact, friction or induction and, therefore, each one has a different perception of the flow

A note on bonus scales

We revisit the optimal bonus scales introduced by Norberg (Norberg, R., 1976, Scandinavian Actuarial Journal (2): 92-107), Borgan, Hoem, and Norberg (Borgan, O., J. Hoem, and R. Norberg, 1981, Scandinavian Actuarial Journal (2): 165-178), and Gilde and Sundt (Gilde, V., and B. Sundt, 1989, Scandinavian Actuarial Journal (1): 13-22) and underline some potential problems of the linear scales. As a possible solution we propose the use of geometric scales..info:eu-repo/semantics/publishedVersio

Particulate organic carbon in agrosystems in the brazilian Semiarid.

Drylands cover about 40% of the planet, in which 44% are occupied with cultivated systems. Covering 45% of Brazilian Semiarid the grasslands are main land use this region. In order to increase biomass production and provide food for goats, sheep and bovines are implanted different agrosystems with differences species Cenchurs ciliairis L. (CC), Opuntia ficus indica Mill. (OF), Gliricidia sepium Jacq. (Walp.) (GS), Leucaena leucocephala Lam. De Wit. (LL). However, with removal of native vegetation (NV) there is a change in supply plant material and hence in soil organic matter (SOM), which is formed by substances in different stages of decomposition. Among the chemical components contained in SOM is carbon (C), the main structuring element of nature. In soils, the C can be in the form particulate organic carbon (POC), coming from the biotic residues being quite susceptible to change of land use, and mineral-associated carbon fraction formed by organomineral complexes that are not available to decomposition . POC is associated with the active compartment and can be lost more eas ly, depending on land use. In sense, to evaluate how the introduction of new species for animal feeding can modify the POC, soil samples were collected at following depths: 0-5, 5-10, 10-15, 15-20, 20-30, 30- 40 cm, with four replicates for uses with different ages: NV (always preserved), CC (30 yr), OF (21 yr), GS (17 yr) and LL (24 yr). The air dried soil was separated in a 53 ?m sieve, where the particles larger than >53 ?m corresponded to POC

Boletim agrometeorológico do ano de 2000 para o municípío de Teresina, PI.

Fonte dos dados meteorológicos; Dados meteorológicos e normais climatológicas; Apresentação dos dados meteorológicos diários do município de Teresina, PI, referentes ao ano de 2000; Comparação das normais climatológicas do município de Teresina, PI, entre o período de 1980 a 1999 e o ano de 2000; Análise dos dados e fatores meteorológicos atuantes.bitstream/item/36445/1/Doc60.pd

Boletim agrometeorológico de 2001 para o Município de Teresina-PI.

Fonte dos dados meteorológicos; Dados meteorológicos e normais climatológicas; Apresentacão dos dados meteorológicos diários do município de Teresina, PI, referentes a 2001 (Tabelas 1 a 12); Comparação das normais climatológicas de médias mensais das variaveis climáticas do município de Teresina, PI, entre os períodos de 1980 a 2000 e ano de 2001 (Fig . 1 a 8); Análise dos dados e fatores meteorológicos atuantes.bitstream/item/36626/1/Doc66.pd

Boletim agrometeorológico do ano de 2004 para o Município de Teresina, PI.

Fonte dos dados meteorológicos; Dados meteorológicos e normais climatológicas; Apresentacão dos dados meteorológicos diários do Município de Teresina, PI, referentes ao ano de 2004; Comparacão das normais climatológicas do Município de Teresina, PI, entre o período de 1980 a 2003 e os dados do ano de 2004; Análise dos dados e fatores meteorológicos atuantes.bitstream/item/35999/1/Doc111.pd

Weyl's Lagrangian in teleparallel form

The main result of the paper is a new representation for the Weyl Lagrangian (massless Dirac Lagrangian). As the dynamical variable we use the coframe, i.e. an orthonormal tetrad of covector fields. We write down a simple Lagrangian - wedge product of axial torsion with a lightlike element of the coframe - and show that this gives the Weyl Lagrangian up to a nonlinear change of dynamical variable. The advantage of our approach is that it does not require the use of spinors, Pauli matrices or covariant differentiation. The only geometric concepts we use are those of a metric, differential form, wedge product and exterior derivative. Our result assigns a variational meaning to the tetrad representation of the Weyl equation suggested by J. B. Griffiths and R. A. Newing