MODELING AND SIMULATION OF THERMOELECTRIC PLANT OF COMBINED CYCLES AND ITS ENVIRONMENTAL IMPACT

The impact any power plant has upon the environment must be minimized as much as possible. Due to its high efficiency, low emission levels and low cooling requirements, combined cycle plants are considered to be environmentally friendly. This study evaluates the effect of operational conditions on pollutants (CO, CO2, SOx, NOx) emissions levels, waste-heat and wastewater of a combined-cycle natural gas and steam power plant. The HYSYS process simulation was used for modelling and simulation. The study clearly shows that the absolute quantity of pollutants emitted is high. Also, it was possible to verify that the unit operate in the condition of minimal emissions regarding the maximum possible, and thus a reduction or elimination of such pollutants is not possible

Anisotropy of Thermal Conductivity and Possible Signature of the Fulde-Ferrell-Larkin-Ovchinnikov state in CeCoIn_5

We have measured the thermal conductivity of the heavy-fermion superconductor CeCoIn_5 in the vicinity of the upper critical field, with the magnetic field perpendicular to the c axis. Thermal conductivity displays a discontinuous jump at the superconducting phase boundary below critical temperature T_0 ~ 1 K, indicating a change from a second to first order transition and confirming the recent results of specific heat measurements on CeCoIn_5. In addition, the thermal conductivity data as a function of field display a kink at a field H_k below the superconducting critical field, which closely coincides with the recently discovered anomaly in specific heat, tentatively identified with the appearance of the spatially inhomogeneous Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconducting state. Our results indicate that the thermal conductivity is enhanced within the FFLO state, and call for further theoretical investigations of the order parameter's real space structure (and, in particular, the structure of vortices) and of the thermal transport within the inhomogeneous FFLO state.Comment: 19 pages, 6 figures, submitted to Prhys. Rev.

Sistemas agroflorestais: restauração ambiental e produção no âmbito da Floresta Ombrófila Mista.

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High-Field Properties of Single-Crystalline Cavo3

The magnetic properties of perovskite CaVO3 single crystals have been studied by means of magnetoresistance r(T, H) and magnetization M(H) measurements in fields to 18T. At 2 K, the magnetoresistance is positive and a maximum value of Dr(18T)/r(0) = 16.5% is found for H//a. The magnetization exhibits a smooth increase at 2 K, reaching values of M(18T) = 0.03, 0.05, 0.17 mB/f.u. for H//a, H//b, and H//c, respectively. This anisotropy found in M(H) is consistent with that observed for Dr(H//a) > Dr(H//b) > Dr(H//c). These results can be interpreted in terms of the field-dependent scattering mechanism of CaVO3.Comment: 10 pages, including 3 figure

How do edge states position themselves in a quantum Hall graphene pn junction?

Recent experiments have shown that electronic Mach-Zehnder interferometers of unprecedented fidelities could be built using a graphene pn junction in the quantum Hall regime. In these junctions, two different edge states corresponding to two different valley configurations are spatially separated and form the two arms of the interferometer. The observed separation, of several tens of nanometers, has been found to be abnormally high and thus associated to unrealistic values of the exchange interaction. In this work, we show that, although the separation is due to exchange interaction, its actual value is entirely governed by the sample geometry and independent of the value of the exchange splitting. Our analysis follows the lines of the classical work of Chklovski-Shklovskii- Glazman on electrostatically induced edge state reconstruction and includes quantitative numerical calculations in the experimental geometries.Comment: 4 pages, 4 figure

Arquitetura da informação dos sites da Agropedia brasilis.

Agropedia brasilis é mais um dos esforços empreendidos na empresa para compatibilizar suas necessidades com as possibilidades oferecidas pelas tecnologias de informação e comunicação. O que se buscou neste trabalho foram os elementos necessários para uma estrutura inicial que atendesse aos interesses mais imediatos dos usuários

Molecular markers applied to evaluation of environmental services in the araucaria forest in Southern Brazil.

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