10,346 research outputs found
Sistema simplificado para melhoria da qualidade da água consumida nas comunidades rurais do semi-árido do Brasil.
Além da quantidade, a qualidade da água também é uma questão que preocupa. A má qualidade da água consumida é a maior responsável pelas doenças endêmicas nos países em desenvolvimento, como por exemplo, hepatite, cólera, febre tifóide, entre outras. Falta de acesso à água de boa qualidade e ao saneamento resulta em centenas de milhões de casos de doenças de veiculação hídrica. No Brasil, de acordo com pesquisa do Censo 2000, 5,9% dos domicílios brasileiros lançam seus esgotos em valas, rios, lagos ou no mar. Dessa proporção, a maior parte ocorre nas áreas rurais (10%) do que nas urbanas (5%). Já os domicílios que não possuem instalações sanitárias chegam a 8,3% do total do país, sendo mais freqüentes nas regiões rurais (35,3%). Essa situação torna-se gritante na área rural da Região Nordeste (60,5%), num contraste brutal com as áreas rurais da Região Sul (7,4%) (IBGE, 2002). Na região do Semi-Árido do Brasil, a população de algumas comunidades rurais, devido à escassez é obrigada a percorrer grandes distâncias para a obtenção de água, na maioria das vezes de péssima qualidade e de turbidez muito elevada. Entre os objetivos deste trabalho, estão a proposição de sistemas simplificados, econômicos, práticos e viáveis para a melhoria da qualidade da água consumida nas comunidades rurais do semi-áridodo Brasil; a comprovação da viabilidade de aplicação desses sistemas; e a apresentação dos resultados obtidos a partir da aplicação desses sistemas.bitstream/CNPMA/7457/1/documentos_53.pd
On the quantumness of correlations in nuclear magnetic resonance
Nuclear Magnetic Resonance (NMR) was successfully employed to test several
protocols and ideas in Quantum Information Science. In most of these
implementations the existence of entanglement was ruled out. This fact
introduced concerns and questions about the quantum nature of such bench tests.
In this article we address some issues related to the non-classical aspects of
NMR systems. We discuss some experiments where the quantum aspects of this
system are supported by quantum correlations of separable states. Such
quantumness, beyond the entanglement-separability paradigm, is revealed via a
departure between the quantum and the classical versions of information theory.
In this scenario, the concept of quantum discord seems to play an important
role. We also present an experimental implementation of an analogous of the
single-photon Mach-Zehnder interferometer employing two nuclear spins to encode
the interferometric paths. This experiment illustrate how non-classical
correlations of separable states may be used to simulate quantum dynamics. The
results obtained are completely equivalent to the optical scenario, where
entanglement (between two field modes) may be present
ENERGETIC ESTIMATION OF HEAT-RECOVERY COKE OVEN
Worldwide, steel production insistently seeks energy strength, pointing out the precision of application of all energy from the raw material with the objective of increasing production with quality and economically viable. In this sense, the energy assessment is the basis adopted to decide on the manufacture of coke in the industry. With this argument, this paper presents an energy analysis of Heat Recovery furnaces through calorific value, a method specified by the Energy Research Company of Brazil and the Brazilian Association of Metals and Materials for application in calculations in a productive environment. The data of the basic raw materials for the production of coke, the technological analysis and the energy estimation in the manufacture of coke in Coke Ovens Heat Recovery can be found in the proposed method. The present work presents result that demonstrate that the active and efficient use of the calorific value of metallurgical coal produces an energy quality coke for the manufacture of pig iron in the blast furnace.
Nonclassical correlation in NMR quadrupolar systems
The existence of quantum correlation (as revealed by quantum discord), other
than entanglement and its role in quantum-information processing (QIP), is a
current subject for discussion. In particular, it has been suggested that this
nonclassical correlation may provide computational speedup for some quantum
algorithms. In this regard, bulk nuclear magnetic resonance (NMR) has been
successfully used as a test bench for many QIP implementations, although it has
also been continuously criticized for not presenting entanglement in most of
the systems used so far. In this paper, we report a theoretical and
experimental study on the dynamics of quantum and classical correlations in an
NMR quadrupolar system. We present a method for computing the correlations from
experimental NMR deviation-density matrices and show that, given the action of
the nuclear-spin environment, the relaxation produces a monotonic time decay in
the correlations. Although the experimental realizations were performed in a
specific quadrupolar system, the main results presented here can be applied to
whichever system uses a deviation-density matrix formalism.Comment: Published versio
STUDY OF PLASMA ION NITRIDING OF AISI H13 STEEL
This work studied the thermochemical treatment of AISI H13 steel used for extrusion of aluminum parts, by plasma ionic nitriding, with the objective of increasing the surface hardness of the mold, by forming an external layer of stable nitrides, increasing the resistance to wear, fatigue, corrosion and thermal resistance. Because it uses ions, plasma ion nitriding is more efficient than liquid and gas nitriding. This process is widely used for ferrous materials and aluminum. The main applications are for extrusion, material injection molds, cutting tools and automotive parts. In this work, samples of the AISI H13 steel were nitrided to be used as aluminum injection molds. The treatment was carried out at 300 oC in a sodium cyanide bath, for a period of 6 h at a pressure of 15 mTorr (2 Pa). The gaseous mixture inside the nitreter consisted of 80% N2 + 20% H2. After treatment, Vickers hardness measurements reached surface values of 963 HV. The results at the end of the treatment showed a 122 µm nitrided layer
Quantum Cosmology in Scalar-Tensor Theories With Non Minimal Coupling
Quantization in the minisuperspace of non minimal scalar-tensor theories
leads to a partial differential equation which is non separable. Through a
conformal transformation we can recast the Wheeler-DeWitt equation in an
integrable form, which corresponds to the minimal coupling case, whose general
solution is known. Performing the inverse conformal transformation in the
solution so found, we can construct the corresponding one in the original
frame. This procedure can also be employed with the bohmian trajectories. In
this way, we can study the classical limit of some solutions of this quantum
model. While the classical limit of these solutions occurs for small scale
factors in the Einstein's frame, it happens for small values of the scalar
field non minimally coupled to gravity in the Jordan's frame, which includes
large scale factors.Comment: latex, 18 page
Environmental Behaviour of Metolachlor and Diuron in a Tropical Soil in the Central Region of Brazil.
The environmental behaviour of metolachlor and diuron was studied in the Central-western region of Brazil, by means of a field study where six experimental plots were installed. The soil was classified as a Latosol, and the soil horizons were characterized. Sorption of metolachlor and diuron was evaluated in laboratory batch experiments. Metolachlor and diuron were applied to the experimental plots on uncultivated soil in October 2003. From this date to March 2004, the following processes were studied: leaching, runoff and dissipation in top soil. Koc of metolachlor varied from 179 to 264 mL g?1 in the soil horizons. Koc of diuron in the Ap horizon was 917 mL g?1, decreasing significantly in the deeper horizons. Field dissipation half-lives of metolachlor and diuron were 18 and 15 days, respectively. In percolated water, metolachlor was detected in concentrations ranging from 0.02 to 2.84 ?g L?1. In runoff water and sediment, metolachlor was detected in decreasing concentrations throughout the period of study. Losses of 0.02% and 0.54% of the applied amount by leaching and runoff, respectively, were observed confirming the high mobility of this herbicide in the environment. In percolated water, diuron was detected with low frequency but in relatively high concentrations (up to 6.29 ?g L?1). In runoff water and soil, diuron was detected in decreasing concentrations until 70 days after application, totalizing 13.9% during the whole sampling period. These results show the importance of practices to reduce runoff avoiding surface water contamination by these pesticides, particularly diuron
Optical properties of titanium oxycarbide thin films
The optical properties of TiC x O y thin films, deposited by reactive dc magnetron sputtering at
different oxygen flow, were investigated by spectroscopic ellipsometry in the energy range of
0.75–4.5 eV. The dielectric functions measured in the energy range of intraband transitions
were analyzed using the classical Drude theory. These results show that free plasma energy
and the damping constant of the films depend strongly on film stoichiometry and on their
oxygen content. The interband contribution to the optical conductivity of these films is in
good agreement with the optical conductivity obtained from first principles calculations based
on density functional theory. Both the experimental and the calculated results show that it is
possible to significantly modify the optical properties of titanium oxycarbide by adjusting the
oxygen content.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência , Tecnologia, Inovação” – CONC-REEQ/443/EEI/2005, PTDC/CTM/69362 e SFRH/BD/27569/200
- …