Quantum-Mechanical Dualities on the Torus

On classical phase spaces admitting just one complex-differentiable structure, there is no indeterminacy in the choice of the creation operators that create quanta out of a given vacuum. In these cases the notion of a quantum is universal, i.e., independent of the observer on classical phase space. Such is the case in all standard applications of quantum mechanics. However, recent developments suggest that the notion of a quantum may not be universal. Transformations between observers that do not agree on the notion of an elementary quantum are called dualities. Classical phase spaces admitting more than one complex-differentiable structure thus provide a natural framework to study dualities in quantum mechanics. As an example we quantise a classical mechanics whose phase space is a torus and prove explicitly that it exhibits dualities.Comment: New examples added, some precisions mad

Voltage dip immunity aspects of power-electronic equipment : recommendations from CIGRE/CIRED/UIE JWG C4.110

This paper presents some of the results from an international working group on voltage-dip immunity. The working group has made a number of recommendations to reduce the adverse impact of voltage dips. Specific recommendations to researchers and manufacturers of powerelectronic equipment are considering all voltage dip characteristics early in the design of equipment; characterize performance of equipment by means of voltage-dip immunity curves; and made equipment with different immunity available

Voltage dip immunity of equipment and installations : messages to stakeholders

This paper presents the messages to the stakeholders on voltage-dip immunity as extracted by UIE WG2 from CIGRE TB412 [1]. The paper summarizes the main recommendations from this technical brochure in the form of messages towards regulators, standard-settingorganizations, network operators, industrial customers, equipment manufacturers, and power quality monitor manufacturers, researchers

Open dual cycle with composition change and limited pressure for prediction of miller engines performance and its turbine temperature

An improved thermodynamic open Dual cycle is proposed to simulate the working of internal combustion engines. It covers both spark ignition and Diesel types through a sequential heat release. This study proposes a procedure that includes (i) the composition change caused by internal combustion, (ii) the temperature excursions, (iii) the combustion efficiency, (iv) heat and pressure losses, and (v) the intake valve timing, following well-established methodologies. The result leads to simple analytical expressions, valid for portable models, optimization studies, engine transformations, and teaching. The proposed simplified model also provides the working gas properties and the amount of trapped mass in the cylinder resulting from the exhaust and intake processes. This allows us to yield explicit equations for cycle work and efficiency, as well as exhaust temperature for turbocharging. The model covers Atkinson and Miller cycles as particular cases and can include irreversibilities in compression, expansion, intake, and exhaust. Results are consistent with the real influence of the fuel-air ratio, overcoming limitations of standard air cycles without the complex calculation of fuel-air cycles. It includes Exhaust Gas Recirculation, EGR, external irreversibilities, and contemporary high-efficiency and low-polluting technologies. Correlations for heat ratio gamma are given, including renewable fuels

A importância da cobertura florestal para o ecossistema e para a sociedade

"O dado já é conhecido, mas nunca é demais repetir, o Rio Grande só possui 2% de suas matas nativas. Ou menos, como querem alguns. Considerando que estamos começando a ser desertos, desaparecimento de riachos e destruição total do solo, chamar a este fato de "problama" é muito pouco. É uma catástrofe - embora seja preciso prestar etençlo para ver, ouvir e sentir a violência que sofre a natureza gaúcha. Mas acordamos a tempo. E, de alguns anos para cá, plantar árvores tornou-se tão necessário quanto plantar soja. Sob pena de, em alguns anos, não termos mais árvores, solo, água e, multo menos, soja." (FECOTRIGO, 1988,p. 4)."Florestas devastadas, o quadro da Região Sul," (ZERO HORA, 04/04/89, p4).Segundo as citações bibliográficas acima expostas, embora sendo apenas duas, pela eloquência dos termos utilizados pode-se perceber facilmente a importância do tema abordado, a necessidade e a falta de cobertura florestal. Mas quais são de fato as reais implicações da existência ou não da cobertura florestal para o ecossistema a para a sociedade como um todo? Através de intensa revisão bibliográfica, enumerando 5 tópicos, quais sejam, efeitos microclimáticos; efeitos sobre o ciclo hidrológico: problemas de conservação do solo (erosão, estabilidade de encostas, etc), efeitos sobre a fauna e; fator econômico, pretende-se justificar eelucidar sobre a importância da cobertura florestal

Maastrichtian-Paleocene deposition in the Paraíba basin, NE Brazil

Abstrac

C and O Isotope Chemostratigraphy and Bulk Chemistry of Reef Limestones of the Tambaba Formation, Paraíba Basin, Northeastern Brazil

This work focuses on the behavior of the C and O isotopes and major and trace element chemistry of the carbonate rocks of the Tambaba Formation, Paraíba Basin, Northeastern Brazil. Thirteen carbonate samples collected from three vertical profiles located perpendicular to the bedding along the coast of the state of Paraíba were analyzed. The δ13C values ranged from 1.6 to 2.8‰ VPDB while the δ18O values ranged from -1.2 to 1.8‰ VPDB, thus suggest a restricted shallow-platform depositional environment. X-ray fluorescence analyses suggested diagenetic changes, such as the replacement of dolomite by calcite (Mn/Sr ratios from 0.6 to 28) and dolomitization, which was identified by high Mg/Ca ratios (0.5 to 0.6). The very low SiO2 and Al2O3 content attested to the low terrigenous material influx. The carbon isotope values suggest that the carbonate rocks were deposited after the Paleocene-Eocene Thermal Maximum (PETM) event

Assessment of myelination in infants and young children by T1 relaxation time measurements using the magnetization-prepared 2 rapid acquisition gradient echoes sequence

Background: Axonal myelination is an important maturation process in the developing brain. Increasing myelin content correlates with the longitudinal relaxation rate (R1=1/T1) in magnetic resonance imaging (MRI). Objective: By using magnetization-prepared 2 rapid acquisition gradient echoes (MP2RAGE) on a 3-T MRI system, we provide R1 values and myelination rates for infants and young children. Materials and methods: Average R1 values in white and grey matter regions in 94 children without pathological MRI findings (age range: 3 months to 6 years) were measured and fitted by a saturating-exponential growth model. For comparison, R1 values of 36 children with different brain pathologies are presented. The findings were related to a qualitative evaluation using T2, magnetization-prepared rapid acquisition gradient echo (MP-RAGE) and MP2RAGE. Results: R1 changes rapidly in the first 16 months of life, then much slower thereafter. R1 is highest in pre-myelinated structures in the youngest subjects, such as the posterior limb of the internal capsule (0.74-0.76 +/- 0.04 s(-1)) and lowest for the corpus callosum (0.37-0.44 +/- 0.03 s(-1)). The myelination rate is fastest in the corpus callosum and slowest in the deep grey matter. R1 is decreased in hypo- and dysmyelination disorders. Myelin maturation is clearly visible on MP2RAGE, especially in the first year of life. Conclusion: MP2RAGE permits a quantitative R1 mapping method with an examination time of approximately 6 min. The age-dependent R1 values for children without MRI-identified brain pathologies are well described by a saturating-exponential function with time constants depending on the investigated brain region. This model can serve as a reference for this age group and to search for indications of subtle pathologies. Moreover, the MP2RAGE sequence can also be used for the qualitative assessment of myelinated structures

Modeling of GRBAS perceptual evaluation using spectral features obtained from an auditory-based filterbank.

Perceptual voice evaluation according to the GRBAS scale is modelled using a linear combination of acoustic parameters calculated after a filter-bank analysis of the recorded voice signals. Modelling results indicate that for breathiness and asthenia more than 55% of the variance of perceptual rates can be explained by such a model, with only 4 latent variables. Moreover, the greatest part of the explained variance can be attributed to only one or two latent variables similarly weighted by all 5 listeners involved in the experiment. Correlation factors between actual rates and model predictions around 0.6 are obtained