Black hole thermalization rate from brane anti-brane model

We develop the quasi-particle picture for Schwarzchild and far from extremal black holes. We show that the thermalization equations of the black hole is recovered from the model of branes and anti-branes. This can also be viewed as a field theory explanation of the relationship between area and entropy for these black holes. As a by product the annihilation rate of branes and anti-branes is computed.Comment: 11 pages, late

Retención de Dicamba por un carbón activo

Se han obtenido las isotermas de retención de dicamba, en disolución acuosa y a las temperaturas de 20°C y 40°C, sobre Un carbón activo preparado a partir de mad· era de olivo. Las isotermas son del tipo L de la clasificación de Giles y se ajustan a la isoterma de Langmuir. Las capacidades de retención son del orden de 10-5 moles . g-l. La entalpía aparente de retención es de + 6,9 Kcal. mol-l, y la entropía aparente de retención toma el valor de + 23,6 cal. °K-I mol-l. Cuando las isotermas de retención de dicamba se obtienen en disolución ciclohexánica, el proceso de retención se hace exotérmico, tomando la entalpia aparente de retención el valor de -5,0 Kcal . mol-l, y la entropia aparente de retención el valor de -15,0 cal. °K-l . mol-l.The retention isotherms of dicamba, in aqueous solution at 20°C and 40°C on an activated carbon, manufactured from olive wood, have been obtalned. These isotherms are of type «L .. of Gile's classificaUon, and have been analysed according to the Langmuir's equation. The retentlon capacitles are 3,16 . 10-5 mol . g-l at 20°C and 2,57 . 10-5 mol. g-l at 40°C. The apparent enthalpy and entropy for the retention .process are + 6,9 Kcal mol-l and + 23,6 cal °K-l mOI-1, respectively. When the isotherms are obtalned in cydohexanic solution, the process is exothermic, and the apparent enthalpy and entropy tak!e the values -5,0 Kcal mol-l and -15,0 cal. °K_l . mol-l, respectively

Holography and Eternal Inflation

We show that eternal inflation is compatible with holography. In particular, we emphasize that if a region is asymptotically de Sitter in the future, holographic arguments by themselves place no bound on the number of past e-foldings. We also comment briefly on holographic restrictions on the production of baby universes.Comment: 14 pages, 3 figures, revtex4, (v2 relation with work of Banks and Fischler clarified, references added

The Entropy of the Rotating Charged Black Threebrane from a Brane-Antibrane System

We show that a model based on a D3-brane--anti-D3-brane system at finite temperature, proposed previously as a microscopic description of the non-rotating black threebrane of type IIB supergravity arbitrarily far from extremality, can also successfully reproduce the entropy of the rotating threebrane with arbitrary charge (including the neutral case, which corresponds to the Kerr black hole in seven dimensions). Our results appear to confirm in particular the need for a peculiar condition on the energy of the two gases involved in the model, whose physical interpretation remains to be elucidated.Comment: 12 pages, references added in section 1 and

Estudio del proceso de retención de 2,4-D en un carbón activo procedente de cáscara de almendra. 1.-Cinética del proceso

The kinetics of the retentiofl process of 2,4-D on one activated carbon from aqueous solution at 10, 20, 30, 40 and 500C has been studied. This carbon was obtained by activation of almond shells. The retention process seems to take place following a reversible mechanism whose order, with respect to the adsorption process is two, and with respect to the desorption process is one.Se ha estudiado la cinética del proceso de retención de 2,4-D, en disolución acuosa, a las temperaturas de 10, 20, 30, 40 Y 50ºC en un carbón activo preparado a partir de cáscara de almendra. El proceso de retención parece transcurrir mediante un mecanismo reversible de orden dos respecto a la adsorción y de orden uno con respecto a la desorción

Can Quantum de Sitter Space Have Finite Entropy?

If one tries to view de Sitter as a true (as opposed to a meta-stable) vacuum, there is a tension between the finiteness of its entropy and the infinite-dimensionality of its Hilbert space. We invetsigate the viability of one proposal to reconcile this tension using $q$-deformation. After defining a differential geometry on the quantum de Sitter space, we try to constrain the value of the deformation parameter by imposing the condition that in the undeformed limit, we want the real form of the (inherently complex) quantum group to reduce to the usual SO(4,1) of de Sitter. We find that this forces $q$ to be a real number. Since it is known that quantum groups have finite-dimensional representations only for $q=$ root of unity, this suggests that standard $q$-deformations cannot give rise to finite dimensional Hilbert spaces, ruling out finite entropy for q-deformed de Sitter.Comment: 10 pages, v2: references added, v3: minor corrections, abstract and title made more in-line with the result, v4: published versio

Estudio del proceso de retención de 2,4-D en un carbón activo procedente de cáscara de almendra. II.-Isotermas de retención

Se han estudiado las isotermas de retención de 2,4-D, en disolución acuosa a las temperaturas de 10, 20, 30, 40 Y 50ºC, en un carbón activo preparado a partir de cáscara de almendra. Los datos obtenidos se han ajustado a las ecuaciones de Langmuir, B.E.T. y López-González, las cuales fueron adaptadas adecuadamente a procesos de adsorción en disolución. Se ha calculado la capacidad de retención del carbón activo utilizado, que es del orden de 10-3 moles de 2,4-D por gramo de carbón. Asúnismo, se han determinado la superficie del mismo accesible a las moléculas de 2,4-D, así como las magnitudes termodinámicas aparentes del proceso.Retention isotherms of 2,4-D in aqueous solution on an activated carbon at 10, 20, 30, 40 and 500C have been obtained. The activated carbon was prepared using almond shells as raw material. The retention process has been studied using the Langmuir, B.E.T. and López-González methods, wich were adapted to adsorption from solutions. The retention capacity of this carbon was around 1O-3mols.g-l. The surface area accesible to 2,4-D molecules as well as the thermodynarnic parameters of the process have been also calculated

Estudio del proceso de retención de 2,4-D en un carbón activo procedente de cáscara de almendra. II.-Isotermas de retención

Retention isotherms of 2,4-D in aqueous solution on an activated carbon at 10, 20, 30, 40 and 50ºC have been obtained. The activated carbon was prepared using almond shells as raw material. The retention process has been studied using the Langmuir, B.E.T. and López-González methods, wich were adapted to adsorption from solutions. The retention capacity of this carbon was around 10-3 mols.g-1. The surface area accesible to 2,4-D molecules as well as the thermodynarnic parameters of the process have been also calculated.Se han estudiado las isotermas de retención de 2,4-D, en disolución acuosa a las temperaturas de 10, 20, 30, 40 Y 50ºC, en un carbón activo preparado a partir de cáscara de almendra. Los datos obtenidos se han ajustado a las ecuaciones de Langmuir, B.E.T. y López-González, las cuales fueron adaptadas adecuadamente a procesos de adsorción en disolución. Se ha calculado la capacidad de retención del carbón activo utilizado, que es del orden de 10-3 moles de 2,4-D por gramo de carbón. Asúnismo, se han determinado la superficie del mismo accesible a las moléculas de 2,4-D, así como las magnitudes termodinámicas aparentes del proceso

Black Hole Entropy and Superconformal Field Theories on Brane-Antibrane Systems

We obtain the enropy of Schwarzschild and charged black holes in D>4 from superconformal gases that live on p=10-D dimensional brane-antibrane systems wrapped on T^p. The preperties of the strongly coupled superconformal theories such as the appearance of hidden dimensions (for p=1,4) and fractional strings (for p=5) are crucial for our results. In all cases, the Schwarzschild radius is given by the transverse fluctuations of the branes and antibranes due to the finite temperature. We show that our results can be generalized to multicharged black holes.Comment: 24 pages in phyzzx.te

Estudio del proceso de retención de 2,4-D en un carbón activo procedente de cáscara de almendra. 1.-Cinética del proceso

Se ha estudiado la cinética del proceso de retención de 2,4-D, en disolución acuosa, a las temperaturas de 10, 20, 30, 40 Y 50ºC en un carbón activo preparado a partir de cáscara de almendra. El proceso de retención parece transcurrir mediante un mecanismo reversible de orden dos respecto a la adsorción y de orden uno con respecto a la desorción.The kinetics of the retentiofl process of 2,4-D on one activated carbon from aqueous solution at 10, 20, 30, 40 and 500C has been studied. This carbon was obtained by activation of almond shells. The retention process seems to take place following a reversible mechanism whose order, with respect to the adsorption process is two, and with respect to the desorption process is one