The Hausdorff moments in statistical mechanics

A new method for solving the Hausdorff moment problem is presented which makes use of Pollaczek polynomials. This problem is severely ill posed; a regularized solution is obtained without any use of prior knowledge. When the problem is treated in the L 2 space and the moments are finite in number and affected by noise or round‐off errors, the approximation converges asymptotically in the L 2 norm. The method is applied to various questions of statistical mechanics and in particular to the determination of the density of states. Concerning this latter problem the method is extended to include distribution valued densities. Computing the Laplace transform of the expansion a new series representation of the partition function Z(β) (β=1/k BT ) is obtained which coincides with a Watson resummation of the high‐temperature series for Z(β)

Excited States in 52Fe and the Origin of the Yrast Trap at I=12+

Excited states in 52Fe have been determined up to spin 10\hbar in the reaction 28Si + 28Si at 115 MeV by using \gamma-ray spectroscopy methods at the GASP array. The excitation energy of the yrast 10+ state has been determined to be 7.381 MeV, almost 0.5 MeV above the well known \beta+-decaying yrast 12+ state, definitely confirming the nature of its isomeric character. The mean lifetimes of the states have been measured by using the Doppler Shift Attenuation method. The experimental data are compared with spherical shell model calculations in the full pf-shell.Comment: 9 pages, RevTeX, 7 figures include

Structure of the icosahedral Ti-Zr-Ni quasicrystal

The atomic structure of the icosahedral Ti-Zr-Ni quasicrystal is determined by invoking similarities to periodic crystalline phases, diffraction data and the results from ab initio calculations. The structure is modeled by decorations of the canonical cell tiling geometry. The initial decoration model is based on the structure of the Frank-Kasper phase W-TiZrNi, the 1/1 approximant structure of the quasicrystal. The decoration model is optimized using a new method of structural analysis combining a least-squares refinement of diffraction data with results from ab initio calculations. The resulting structural model of icosahedral Ti-Zr-Ni is interpreted as a simple decoration rule and structural details are discussed.Comment: 12 pages, 8 figure

New Mechanics of Traumatic Brain Injury

The prediction and prevention of traumatic brain injury is a very important aspect of preventive medical science. This paper proposes a new coupled loading-rate hypothesis for the traumatic brain injury (TBI), which states that the main cause of the TBI is an external Euclidean jolt, or SE(3)-jolt, an impulsive loading that strikes the head in several coupled degrees-of-freedom simultaneously. To show this, based on the previously defined covariant force law, we formulate the coupled Newton-Euler dynamics of brain's micro-motions within the cerebrospinal fluid and derive from it the coupled SE(3)-jolt dynamics. The SE(3)-jolt is a cause of the TBI in two forms of brain's rapid discontinuous deformations: translational dislocations and rotational disclinations. Brain's dislocations and disclinations, caused by the SE(3)-jolt, are described using the Cosserat multipolar viscoelastic continuum brain model. Keywords: Traumatic brain injuries, coupled loading-rate hypothesis, Euclidean jolt, coupled Newton-Euler dynamics, brain's dislocations and disclinationsComment: 18 pages, 1 figure, Late

In situ, real-time visualization of electrochemistry using magnetic resonance imaging

The drive to develop better electrochemical energy storage devices requires the development of not only new materials, but also better understanding of the underpinning chemical and dynamical processes within such devices during operation, for which new analytical techniques are required. Currently, there are few techniques that can probe local composition and transport in the electrolyte during battery operation. In this paper, we report a novel application of magnetic resonance imaging (MRI) for probing electrochemical processes in a model electrochemical cell. Using MRI, the transport and zinc and oxygen electrochemistry in an alkaline electrolyte, typical of that found in zinc-air batteries, are investigated. Magnetic resonance relaxation maps of the electrolyte are used to visualize the chemical composition and electrochemical processes occurring during discharge in this model metal-air battery. Such experiments will be useful in the development of new energy storage/conversion devices, as well as other electrochemical technologies

EVOLUTION OF THE FUSION LIKE PROCESS AROUND THE FERMI ENERGY

The study of evaporation residue from the Ne + Ag system shows that there is qualitative change in the reaction mechanism in the Fermi energy domain. At 20 MeV/u the projectile is mostly absobered by the target, while at 30-37 MeV/u a continious range of mass transfer with a large transverse momentum is observed

Uso de la lama del lago “El Nihuil”, digestión anaeróbica para obtención de biogás

Esta investigación consiste en mitigar los efectos naturales y artificiales causados en un lago de una localidad turística de la provincia de Mendoza. Una de las soluciones más efectivas para este caso es la poda de las algas del mismo. Pero ésta acarrea el inconveniente: deposición final de estos desechos. Se propuso aprovechar la degradación de estas plantas en forma anaeróbica. Se realizaron pruebas a escala, las que comprenden dos etapas. En la primera se verificó la producción de gas combustible y se realizaron análisis químicos de la materia antes y después de la degradación. En la segunda se midió el gas producido. Al final de este proceso se consigue también una disminución de la masa residual, la que a su vez puede ser aprovechada como fertilizante y/o mejorador de suelos. En la actualidad es fundamental encontrar nuevas fuentes de energías que contaminen menos, y un mayor aprovechamiento de los residuos.This project consists in mitigating the natural and artificial effects caused in a touristic village’s lake from Mendoza. One of the best solutions is pruning alga of the lake. But this one produces another inconvenient which is his final deposition. The solution propounded is: use it as a source of biogas degrading this plant. The anaerobic digestion was studied, and then there were done small experiment in two stages. In the first one was verified the combustible gas production. There was done a chemical analysis of this matter after the degradation and before it. In the second part of the experience we measured the gas produced. At the end of this process we had less waste, and this one can be used as fertilizer and to improve ground mechanical properties. It is truly important to found new sources of energy that are less polluting and a better use of waste.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Uso de la lama del lago “El Nihuil”, digestión anaeróbica para obtención de biogás

Esta investigación consiste en mitigar los efectos naturales y artificiales causados en un lago de una localidad turística de la provincia de Mendoza. Una de las soluciones más efectivas para este caso es la poda de las algas del mismo. Pero ésta acarrea el inconveniente: deposición final de estos desechos. Se propuso aprovechar la degradación de estas plantas en forma anaeróbica. Se realizaron pruebas a escala, las que comprenden dos etapas. En la primera se verificó la producción de gas combustible y se realizaron análisis químicos de la materia antes y después de la degradación. En la segunda se midió el gas producido. Al final de este proceso se consigue también una disminución de la masa residual, la que a su vez puede ser aprovechada como fertilizante y/o mejorador de suelos. En la actualidad es fundamental encontrar nuevas fuentes de energías que contaminen menos, y un mayor aprovechamiento de los residuos.This project consists in mitigating the natural and artificial effects caused in a touristic village’s lake from Mendoza. One of the best solutions is pruning alga of the lake. But this one produces another inconvenient which is his final deposition. The solution propounded is: use it as a source of biogas degrading this plant. The anaerobic digestion was studied, and then there were done small experiment in two stages. In the first one was verified the combustible gas production. There was done a chemical analysis of this matter after the degradation and before it. In the second part of the experience we measured the gas produced. At the end of this process we had less waste, and this one can be used as fertilizer and to improve ground mechanical properties. It is truly important to found new sources of energy that are less polluting and a better use of waste.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES