Loop Equations and the Topological Phase of Multi-Cut Matrix Models

We study the double scaling limit of mKdV type, realized in the two-cut Hermitian matrix model. Building on the work of Periwal and Shevitz and of Nappi, we find an exact solution including all odd scaling operators, in terms of a hierarchy of flows of $2\times 2$ matrices. We derive from it loop equations which can be expressed as Virasoro constraints on the partition function. We discover a ``pure topological" phase of the theory in which all correlation functions are determined by recursion relations. We also examine macroscopic loop amplitudes, which suggest a relation to 2D gravity coupled to dense polymers.Comment: 24p

EVALUATION OF THE COMBUSTION PROCESS OF COFFEE HUSK SAMPLES IN A DROP TUBE FURNACE (DTF)

Thermal conversion processes that use coffee husk are an alternative to solve the environmental problems of disposal and waste burning in open places and avoid greenhouse gases emissions. The present study evaluates in natura coffee husk samples and residues obtained from a combustion process in a Drop Tube Furnace (DTF). Such an evaluation consists in understanding the efficiency of the burning process, therefore the activation energies (Ea) of the combustion process for both samples were determined. The isoconversional kinetic method (Model Free Kinetics) was used for the determination of the Ea values of the samples. The Ea values of the main stages of the combustion process (devolatilization and carbonization) for both samples were compared. Thermogravimetric (TG) and Derivative Thermogravimetric (DTG) data at five heating rates (10, 15, 20, 25 and 30 oC min-1) were used for the determination of hemicellulose, cellulose and residual lignin. SEM (Scanning Electronic Microscopy) images and EDS (Energy Dispersive Spectroscopy) analysis were applied as complementary techniques in the combustion process. The results show that for both samples the Ea values were higher for the carbonization step than for devolatilization. The Ea values for the stages of devolatilization and carbonization for the residues were 33 and 15% lower than those for the in natura coffee husk samples. The lower Ea values in both steps for the residues are indicative of a reduction in the complexity of the reaction mechanism, which can be a parameter for the evaluation of the biomass combustion process. According to the SEM images, the residues showed exploded surfaces caused by the combustion process, whereas in the in natura samples a denser and robust structure was observed. The ash formed after the combustion process in the thermobalance was also evaluated by SEM and EDS analyses and showed a more homogenous structure with tiny particles in comparison with the in natura coffee husk samples. The EDS analysis confirmed the presence of precursor elements in the samples, such as potassium and other inorganic materials, which were intensified after the combustion process

Covariant Symplectic Structure and Conserved Charges of New Massive Gravity

We show that the symplectic current obtained from the boundary term, which arises in the first variation of a local diffeomorphism invariant action, is covariantly conserved for any gravity theory described by that action. Therefore, a Poincare invariant 2-form can be constructed on the phase space, which is shown to be closed without reference to a specific theory. Finally, we show that one can obtain a charge expression for gravity theories in various dimensions, which plays the role of the Abbott-Deser-Tekin (ADT) charge for spacetimes with non-constant curvature backgrounds, by using the diffeomorphism invariance of the symplectic 2-form. As an example, we calculate the conserved charges of some solutions of New Massive Gravity (NMG) and compare the results with the previous works.Comment: 18 pages, No figures, RevTEX4.1; ver 2: minor corrections, version accepted for publication in Physical Review

On Superpotentials and Charge Algebras of Gauge Theories

We propose a new "Hamiltonian inspired" covariant formula to define (without harmful ambiguities) the superpotential and the physical charges associated to a gauge symmetry. The criterion requires the variation of the Noether current not to contain any derivative terms in \partial_{\mu}\delta \f. The examples of Yang-Mills (in its first order formulation) and 3-dimensional Chern-Simons theories are revisited and the corresponding charge algebras (with their central extensions in the Chern-Simons case) are computed in a straightforward way. We then generalize the previous results to any (2n+1)-dimensional non-abelian Chern-Simons theory for a particular choice of boundary conditions. We compute explicitly the superpotential associated to the non-abelian gauge symmetry which is nothing but the Chern-Simons Lagrangian in (2n-1) dimensions. The corresponding charge algebra is also computed. However, no associated central charge is found for $n \geq 2$. Finally, we treat the abelian p-form Chern-Simons theory in a similar way.Comment: 32 pages, LaTex. The proposal is restricted to first order theories. An appendix is added. Some references are adde

Methodology for the study of the dolomite porosity in essay of interrupted sulfation

The aim of this work is to propose a methodology to evaluate the evolution of the pore blockage of limestone during the sulfation reaction. The experiments were performed for a national limestone (dolomite) with average particle size of 545 μm in interrupted sulfation tests were conducted at seven different times and at three different temperatures of the process. The empirical data were obtained from porosimetry tests to establish BET surface area, volume and average size of pore and distribution of pore sizes of the sulfated samples. Thermogravimetric tests were performed to evaluate the preparation methodology of the samples used in the porosimetry tests.FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Content aggregation, visualization and emergent properties in computer simulations

With the rapidly growing amounts of information, visualization is becoming increasingly important, as it allows users to easily explore and understand large amounts of information. However the field of information visualiza- tion currently lacks sufficient theoretical foundations. This article addresses foundational questions connecting information visualization with computing and philosophy studies. The idea of multiscale information granula- tion is described based on two fundamental concepts: information (structure) and computation (process). A new information processing paradigm of Granular Computing enables stepwise increase of granulation/aggregation of information on different levels of resolution, which makes possible dynamical viewing of data. Information produced by Google Earth is an illustration of visualization based on clustering (granulation) of information on a succession of layers. Depending on level, specific emergent properties become visible as a result of different ways of aggregation of data/information. As information visualization ultimately aims at amplifying cognition, we discuss the process of simulation and emulation in relation to cognition, and in particular visual cognition

THE CALCIUM LOOPING CYCLE STUDY FOR CAPTURING CARBON DIOXIDE APPLIED TO THE ENERGY GENERATION

The calcium looping process (Ca-L) is a promising technology to reduce of the carbon dioxide (CO2) emissions when applied in energy generation systems. Ca-based materials (usually limestone) are used in this process as CO2 sorbents. Thus, the CO2 capture occurs by the reversible reaction between calcium oxide (CaO) and CO2, resulting in the calcium carbonate form (CaCO3). Compared to other technologies applied to carbon sequestration process, the Ca-L offers additional advantages such: the use of fluidized bed technology that is already well established; this process occurs at high temperature, and the excess of heat generated can be recovered; the cost of limestone sorbents is low because of its wide availability. However, in the applying the Ca-L process is essential to understand the mechanism and the effect of partial pressure of CO2 in both, calcination and carbonation processes; to investigate the effect of sintering and to evaluate the sorbent activity decay. In this paper, empirical technique such as thermogravimetry is applied to investigate the reactivity of dolomite as CO2 sorbent. The effect of CO2 high concentrations in both calcination/carbonation processes is also investigated

STUDY OF THERMAL DECOMPOSITION AND IGNITION TEMPERATURE OF BAGASSE, COAL AND THEIR BLENDS

In Brazil, due to its availability, sugar cane bagasse has a high potential for power generation. The knowledge of ignition behavior, as well as the knowledge of the chemical kinetics, in of fuels combustion process is important features in boilers projects and in the stability of the combustion process control. The aim of this study is to investigate the thermal behavior of sugar cane bagasse, coal and their blends. The methodology proposed by Tognotti et al. (1985) was applied to determine the ignition temperature for all samples. Ignition temperatures were 256oC for neat bagasse and 427oC for neat coal, and 275oC for both blends (50-50% and 25-75%). The Model-Free Kinetics was applied to determine the apparent activation energy (Eα) of the thermal decomposition of sugar cane bagasse. For the two major events of mass loss of bagasse which correspond to the thermal decomposition of organic matter (mainly hemicellulose, cellulose and lignin), average values of Eα were obtained for both combustion and pyrolysis processes. In synthetic air atmosphere, the Eα were 170.8±26.3 kJ⋅mol-1 and 277.8±58.6 kJ⋅mol-1, while in nitrogen atmosphere, the Eα were 185.0 ± 11.4 kJ⋅mol-1 and 82.1±44.4 kJ⋅mol-1. The results obtained can be explained by synergistic effects when both bagasse and coal were blended, changing the fuel reactivity

A topological limit of gravity admitting an SU(2) connection formulation

We study the Hamiltonian formulation of the generally covariant theory defined by the Lagrangian 4-form L=e_I e_J F^{IJ}(\omega) where e^I is a tetrad field and F^{IJ} is the curvature of a Lorentz connection \omega^{IJ}. This theory can be thought of as the limit of the Holst action for gravity for the Newton constant G goes to infinity and Immirzi parameter goes to zero, while keeping their product fixed. This theory has for a long time been conjectured to be topological. We prove this statement both in the covariant phase space formulation as well as in the standard Dirac formulation. In the time gauge, the unconstrained phase space of theory admits an SU(2) connection formulation which makes it isomorphic to the unconstrained phase space of gravity in terms of Ashtekar-Barbero variables. Among possible physical applications, we argue that the quantization of this topological theory might shed new light on the nature of the degrees of freedom that are responsible for black entropy in loop quantum gravity.Comment: Appendix added where moldels leading to boundary degrees of freedom are constructed. This version will appear in PRD