Joel Cisneros - Academia.edu (original) (raw)
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Papers by Joel Cisneros
Talanta, 2005
The sonogel-carbon electrode is a new class of sol-gel electrode that exhibit favourable mechanic... more The sonogel-carbon electrode is a new class of sol-gel electrode that exhibit favourable mechanics and electrics properties to be used as electrochemical sensor. In this paper, a modified sonogel-carbon electrode is proposed to determine mercury at trace levels. The modified electrode is obtained by electropolymerization of 3-methylthiophene on the surface of a bare sonogel-carbon electrode. This electrode shows high selectivity and sensitivity and linear response towards Hg(II), with a detection limit of 1.4 × 10 −3 mg l −1 . The electrode is reusable by a simple chemical cleaning procedure. No deterioration was observed in the electrode response during at least 1 week of successive measurements.
Revista Mexicana De Astronomia Y Astrofisica, 2000
The second order virial equations are employed to analyze in a first approximation the stability ... more The second order virial equations are employed to analyze in a first approximation the stability of a self-gravitating fluid made up of two confocal spheroids with solid-body differential rotation. The equilibrium solution for such a model is known to consist of a series which in the present study is shown to be, almost throughout, stable. On the other hand, the series contains some spheroids of zero frequency, an indication that secondary sequences of tri-axial figures could branch off from them. Such is indeed the case, even if the bifurcated sequences consist exclusively of Dedekind-type figures, as they are static with internal motions of differential vorticity. Anyway, Jacobi-type figures could not beforehand be expected to give out from the model, since it would be inconsistent with Hamy's theorem.
Revista Mexicana De Astronomia Y Astrofisica, 2004
The second order virial equations are employed to analyze, in a first approximation, the stabilit... more The second order virial equations are employed to analyze, in a first approximation, the stability of a self-gravitating fluid made up of two confocal ellipsoids carrying internal currents of differential vorticity, which allow their equilibrium. These Dedekind-type figures result because some of the members of a series of inhomogeneous rotating spheroids have null frequencies, from which they bifurcate in sequences of fixed ɛ, the body's relative density. We find that such sequences have each an instability regime, which is wide at low ɛ , and becomes gradually narrower as ɛ increases. Instability persists--even for very large ɛ --at the final portion of the sequences, where the figures whose internal ellipsoid has the most prominent equatorial flattening are located.
Mediante la técnica del virial a segundo armónico se analiza, en primera aproximación, la estabil... more Mediante la técnica del virial a segundo armónico se analiza, en primera aproximación, la estabilidad de un fluido autogravitante estático, tipo Dedekind, que consiste de dos elipsoides confocales de diferente densidad. Estas figuras, que mantienen su equilibrio en base a corrientes internas de vorticidad diferencial, resultan debido a que algunos de los miembros de una serie de esferoides inhomogéneos rotantes son de frecuencia nula, de donde se bifurcan en secuencias de ε (la densidad relativa del cuerpo) fija. Se encuentra que tales secuencias tienen un régimen de inestabilidad, el cual es tanto más amplio mientras menor sea ε, pero que se estrecha al incrementar ε. Para ε muy grande la inestabilidad persiste en la porción final de las secuencias, en donde se hallan las figuras cuyo elipsoide interno tiene la excentricidad ecuatorial más prominente.
Talanta, 2005
The sonogel-carbon electrode is a new class of sol-gel electrode that exhibit favourable mechanic... more The sonogel-carbon electrode is a new class of sol-gel electrode that exhibit favourable mechanics and electrics properties to be used as electrochemical sensor. In this paper, a modified sonogel-carbon electrode is proposed to determine mercury at trace levels. The modified electrode is obtained by electropolymerization of 3-methylthiophene on the surface of a bare sonogel-carbon electrode. This electrode shows high selectivity and sensitivity and linear response towards Hg(II), with a detection limit of 1.4 × 10 −3 mg l −1 . The electrode is reusable by a simple chemical cleaning procedure. No deterioration was observed in the electrode response during at least 1 week of successive measurements.
Revista Mexicana De Astronomia Y Astrofisica, 2000
The second order virial equations are employed to analyze in a first approximation the stability ... more The second order virial equations are employed to analyze in a first approximation the stability of a self-gravitating fluid made up of two confocal spheroids with solid-body differential rotation. The equilibrium solution for such a model is known to consist of a series which in the present study is shown to be, almost throughout, stable. On the other hand, the series contains some spheroids of zero frequency, an indication that secondary sequences of tri-axial figures could branch off from them. Such is indeed the case, even if the bifurcated sequences consist exclusively of Dedekind-type figures, as they are static with internal motions of differential vorticity. Anyway, Jacobi-type figures could not beforehand be expected to give out from the model, since it would be inconsistent with Hamy's theorem.
Revista Mexicana De Astronomia Y Astrofisica, 2004
The second order virial equations are employed to analyze, in a first approximation, the stabilit... more The second order virial equations are employed to analyze, in a first approximation, the stability of a self-gravitating fluid made up of two confocal ellipsoids carrying internal currents of differential vorticity, which allow their equilibrium. These Dedekind-type figures result because some of the members of a series of inhomogeneous rotating spheroids have null frequencies, from which they bifurcate in sequences of fixed ɛ, the body's relative density. We find that such sequences have each an instability regime, which is wide at low ɛ , and becomes gradually narrower as ɛ increases. Instability persists--even for very large ɛ --at the final portion of the sequences, where the figures whose internal ellipsoid has the most prominent equatorial flattening are located.
Mediante la técnica del virial a segundo armónico se analiza, en primera aproximación, la estabil... more Mediante la técnica del virial a segundo armónico se analiza, en primera aproximación, la estabilidad de un fluido autogravitante estático, tipo Dedekind, que consiste de dos elipsoides confocales de diferente densidad. Estas figuras, que mantienen su equilibrio en base a corrientes internas de vorticidad diferencial, resultan debido a que algunos de los miembros de una serie de esferoides inhomogéneos rotantes son de frecuencia nula, de donde se bifurcan en secuencias de ε (la densidad relativa del cuerpo) fija. Se encuentra que tales secuencias tienen un régimen de inestabilidad, el cual es tanto más amplio mientras menor sea ε, pero que se estrecha al incrementar ε. Para ε muy grande la inestabilidad persiste en la porción final de las secuencias, en donde se hallan las figuras cuyo elipsoide interno tiene la excentricidad ecuatorial más prominente.