Energy fluxes in helical magnetohydrodynamics and dynamo action

Renormalized viscosity, renormalized resistivity, and various energy fluxes are calculated for helical magnetohydrodynamics using perturbative field theory. The calculation is to first-order in perturbation. Kinetic and magnetic helicities do not affect the renormalized parameters, but they induce an inverse cascade of magnetic energy. The sources for the the large-scale magnetic field have been shown to be (1) energy flux from large-scale velocity field to large-scale magnetic field arising due to nonhelical interactions, and (2) inverse energy flux of magnetic energy caused by helical interactions. Based on our flux results, a premitive model for galactic dynamo has been constructed. Our calculations yields dynamo time-scale for a typical galaxy to be of the order of $10^8$ years. Our field-theoretic calculations also reveal that the flux of magnetic helicity is backward, consistent with the earlier observations based on absolute equilibrium theory.Comment: REVTEX4; A factor of 2 corrected in helicit

Comparación inter-laboratorios del OIEA para la química del agua geotérmica: críticas sobre la incertidumbre analítica, la precisión y el modelado del yacimiento geotérmico de Los Azufres, México

The results of International Atomic Energy Agency (IAEA) inter-laboratory comparison program reported in the literature during 1992 and 2004 were analyzed to estimate analytical uncertainty in the geochemical analysis of geothermal waters. Statistical data treatments for the detection and elimination of outliers and extremums were performed using five methods: (i) data visualization (or raw data statistics); (ii) mean ( x ) and standard deviation (s) calculation after eliminating outliers with x ± 2s ; (iii) median and median absolute difference (MAD); (iv) Huber method; and (v) single-outlier type multiple test method involving Dixon, Grubbs, skewness and kurtosis tests at 99% confidence level. The results are reported in scientific notation with one significant digit of uncertainty. A comparative study of all the five statistical data treatment methods suggests that the fifth method provides better results for the statistical analysis of experimental measurements. A preliminary evaluation for the analytical accuracy of geochemical analysis of geothermal waters, prepared by dissolving 4.585 g CaCl2 (98.2%), 16.5 g NaCl (99.9%), 3.58 g MgCl2 (99.0%), 0.74 g Na2SO4 (99.0%) and 0.95 g KCl (99.5%) in 1 liter of solution, is presented. The analysis of Na+ and K+ are reasonably accurate, while Mg2+ and SO4 2- have high inaccuracy. The accuracy of Ca2+ and Cl- analyses is in-between. A systematic analysis of the results suggests that the present inaccuracy in the measurements of Mg2+, Ca2+, SO4 2- and Cl- are probably associated with the sample preparation. The relations between the coefficient of variation (i.e. % analytical uncertainty) and concentration of each element are derived, which are used for the propagation of uncertainty in the geochemical calculations of geothermal systems. The uncertainty propagation procedure is illustrated in the calculation of Los Azufres geothermal reservoir temperature and vapor fraction. The uncertainty in the estimated temperature is ±20 K, which means that the changes in the geothermal reservoir fluid characteristics during its exploitation are generally within the uncertainty.Los resultados del programa de comparación inter-laboratorios del Organismo Internacional de Energía Atómica (OIEA), reportados en la literatura durante el período 1992 y 2004, han sido analizados para estimar la incertidumbre en los análisis geoquímicos de las aguas geotérmicas. Se realizó el tratamiento estadístico de los datos para la detección y eliminación de valores atípicos y extremos con cinco métodos: (i) la visualización de los datos (o las estadísticas de los datos en bruto); (ii) el cálculo de media ( x ) y la desviación estándar (s), después de la eliminación de valores atípicos con el criterio x ± 2s ; (iii) la mediana y la diferencia media absoluta (MAD); (iv) el método de Huber; y (v) el método de prueba múltiple del tipo del valor atípico que combina las pruebas de Dixon, Grubbs, asimetría y curtosis en el nivel de confianza del 99%. Los resultados fueron presentados en la notación científica con la incertidumbre de un dígito significativo. Un estudio comparativo de los cinco métodos estadísticos de tratamientos de datos sugiere que el quinto método proporciona mejores resultados para el análisis estadístico de las mediciones experimentales. Se presenta una evaluación preliminar de la exactitud analítica de los análisis geoquímicos de las aguas geotermales, preparadas con la disolución de 4,585 g de CaCl2 (98.2%), 16,5 g de NaCl (99.9%), 3,58 g de MgCl2 (99.0%), 0,74 g de Na2SO4 (99,0%) y 0,95 g de KCl (99,5%) en 1 litro de solución. Los análisis de Na+ y K+ son razonablemente precisos, mientras que Mg2+ y SO4 2- tienen una inexactitud alta. La exactitud de Ca2+ y Cl- está en el medio. Un análisis sistemático de los resultados sugiere que la inexactitud en la medición de Mg2+, Ca2+, SO4 2- y Cl- está probablemente relacionada con la preparación de la muestra. Las relaciones entre el coeficiente de variación (% de incertidumbre analítica) y la concentración de cada elemento se derivaron, y posteriormente se utilizaron para la propagación de la incertidumbre en los cálculos geoquímicos de sistemas geotérmicos. El procedimiento de cálculo se ilustra con la propagación de la incertidumbre en el cálculo de la temperatura y la fracción de vapor en el sistema geotérmico del yacimiento de Los Azufres. La incertidumbre en la temperatura estimada es de ± 20 K, lo que significa que los cambios en las características de los fluidos del yacimiento geotérmico durante su explotación están en general dentro de la incertidumbre

Calculation of renormalized viscosity and resistivity in magnetohydrodynamic turbulence

A self-consistent renormalization (RG) scheme has been applied to nonhelical magnetohydrodynamic turbulence with normalized cross helicity $\sigma_c =0$ and $\sigma_c \to 1$. Kolmogorov's 5/3 powerlaw is assumed in order to compute the renormalized parameters. It has been shown that the RG fixed point is stable for $d \ge d_c \approx 2.2$. The renormalized viscosity $\nu^*$ and resistivity $\eta^*$ have been calculated, and they are found to be positive for all parameter regimes. For $\sigma_c=0$ and large Alfv\'{e}n ratio (ratio of kinetic and magnetic energies) $r_A$, $\nu^*=0.36$ and $\eta^*=0.85$. As $r_A$ is decreased, $\nu^*$ increases and $\eta^*$ decreases, untill $r_A \approx 0.25$ where both $\nu^*$ and $\eta^*$ are approximately zero. For large $d$, both $\nu^*$ and $\eta^*$ vary as $d^{-1/2}$. The renormalized parameters for the case $\sigma_c \to 1$ are also reported.Comment: 19 pages REVTEX, 3 ps files (Phys. Plasmas, v8, 3945, 2001

Heteroduplex analysis of the RNA of clone 3 Moloney murine sarcoma virus

Heteroduplex analysis of the RNA isolated from purified virions of clone 3 Moloney murine sarcoma virus (M-MSV) hybridized to cDNA's from Moloney murine leukemia virus (M-MLV) and clone 124 M-MSV shows that the main physical component of clone 3 RNA is missing all or most of the 1.5-kilobase (kb) clone 124 M-MSV specific sequence denoted beta s (S. Hu et al. Cell 10:469-477, 1977). This sequence is either deleted in clone 3 RNA or substituted by a very short (0.3-kilobase) sequence. In other respects, clone 3 and clone 124 RNAs show the same heteroduplex structure relative to M-MLV. Since beta s is believed to contain the src gene(s) of clone 124 RNA, this result leaves as an unresolved question the nature of the src gene(s) of the clone 3 M-MSV RNA complex

Cohesion, Elastic Constants and Vibrational Mechanics of Fcc Platinum

A model in real space has been developed by extending the generalized form of the exponential potential known as extended generalized exponential potential (EGEP) to account for (a) the correct nature of repulsive and attractive components of forces for all the separations in general and that of small separations in particular, (b) the three-body forces such as volume forces in an indirect way in the framework of EGEP through the parameter n, (c) the dielectric screening functions in an alternative and simpler form through the parameter m. The model is employed to compute the cohesive energy, second-order elastic constants and phenon spectra for fcc platinum. The predictions show promising agreement with experimental findings.Author Affiliation: Divesh Verma A. F. School of Engineering and Technology, Dhauj-121 004, Haryana, India M L Verma* and A Verma Department of Physics, GGDSD College, Palwal-121 102, Haryana, India and R P S Rathore Department of Physics, B.M.A.S. Engineering College, Agra-282 002, Uttar Pradesh, India1.A. F. School of Engineering and Technology, Dhauj-121 004, Haryana, India 2.Department of Physics, GGDSD College, Palwal-121 102, Haryana, India 3.Department of Physics, B.M.A.S. Engineering College, Agra-282 002, Uttar Pradesh, Indi