Magnetic properties of a spin-1 Triangular Ising system

We studied some magnetic behaviors of Blume-Capel (BC) model in a site diluted triangular lattice by means of the effective-field theory (EFT) with correlations. The effects of the exchange interaction (J), crystal field (D), concentration (p) and temperature (T) on the magnetic properties of spin-1 BC model in a triangular lattice such as magnetization, susceptibility, phase diagram and hysteresis behaviors are investigated, in detail. The phase diagrams of the system are presented in two different planes. The tricritical point as well as tetracritical and critical end special points are found as depending on the physical parameters of the system. Moreover, when the hysteresis behaviors of the system are examined, the single and double hysteresis loop are observed for various values of the physical parameters. We show that the hysteresis loops have different coercive field points in which the susceptibility make peak at these points

Domain Wall Depinning in Random Media by AC Fields

The viscous motion of an interface driven by an ac external field of frequency omega_0 in a random medium is considered here for the first time. The velocity exhibits a smeared depinning transition showing a double hysteresis which is absent in the adiabatic case omega_0 --> 0. Using scaling arguments and an approximate renormalization group calculation we explain the main characteristics of the hysteresis loop. In the low frequency limit these can be expressed in terms of the depinning threshold and the critical exponents of the adiabatic case.Comment: 4 pages, 3 figure

Melting of Flux Lines in an Alternating Parallel Current

We use a Langevin equation to examine the dynamics and fluctuations of a flux line (FL) in the presence of an {\it alternating longitudinal current} $J_{\parallel}(\omega)$. The magnus and dissipative forces are equated to those resulting from line tension, confinement in a harmonic cage by neighboring FLs, parallel current, and noise. The resulting mean-square FL fluctuations are calculated {\it exactly}, and a Lindemann criterion is then used to obtain a nonequilibrium `phase diagram' as a function of the magnitude and frequency of $J_{\parallel}(\omega)$. For zero frequency, the melting temperature of the mixed phase (a lattice, or the putative "Bose" or "Bragg Glass") vanishes at a limiting current. However, for any finite frequency, there is a non-zero melting temperature.Comment: 5 pages, 1 figur

Extracción en fase sólida de β-sitosterol y α-tocoferol de destilados de aceite de girasol desodorizado utilizando zeolita desilicada

In this study, the efficiency of using zeolite-based adsorbents in a solid phase extraction (SPE) procedure of α-tocopherol and β-sitosterol isolation from Sunflower Oil Deodorizer Distillate (SuDOD) with­out pre-treatment was investigated. The results showed that 99.2% α-tocopherol and 97.3% β-sitosterol were suc­cessfully isolated as pure fractions from SuDOD, when desilicated ZSM-5-type zeolite (DSiZSM-5) was used as adsorbent on a SPE. A simple and rapid HPLC method for simultaneous α-tocopherol and β-sitosterol analysis was developed and validated according to AOAC guidelines. It was found that the inclusion of a DSiZSM-5 SPE step increased the precision of the α-tocopherol and β-sitosterol analysis. In conclusion, DSiZSM-5 zeo­lite was proven to be an efficient adsorbent which can be used not only for the recovery of α-tocopherol and β-sitosterol from SuDOD in industrial scale, but also in a laboratory scale clean-up method prior to the analysis of α-tocopherol and β-sitosterol.En este estudio, se investigó la eficacia del uso de adsorbentes a base de zeolita en el procedimiento de extracción en fase sólida (EFS) para el aislamiento de α-tocoferol y β-sitosterol a partir de destilados de aceites de girasol desodorizados (SuDOD) sin ningún tratamiento previo. Los resultados mostraron que el 99,2% de α-tocoferol y el 97,3% de β-sitosterol se aislaron con éxito como fracciones puras de SuDOD, cuando se usó zeolita de tipo ZSM-5 desilicado (DSiZSM-5) como adsorbente en una EFS. Se desarrolló y validó un método HPLC simple y rápido para el análisis simultáneo de α-tocoferol y β-sitosterol de acuerdo con las directrices de la AOAC. Se encontró que la inclusión del paso DSiZSM-5 EFS aumentó la precisión del análisis de α-tocoferol y β-sitosterol. En conclusión, se demostró que la zeolita DSiZSM-5 es un adsorbente eficiente que puede usarse, no solo para la recuperación de α-tocoferol y β-sitosterol de SuDOD a escala industrial, sino también en un método de limpieza a escala de laboratorio antes del análisis de α-tocoferol y β-sitosterol

Heating of magnetic fluid systems driven by circularly polarized magnetic field

Cataloged from PDF version of article.A theory is presented to calculate the heat dissipation of a magnetic suspension, a ferrofluid, driven by7 circularly polarized magnetic field. Theory is tested by in vitro experiments and it is shown that, regardless of the character of the relaxation process, linearly and circularly polarized magnetic field excitations, having the same root-mean-square magnitude, are equivalent in terms of heating efficiency. (C) 2010 Elsevier B.V. All rights reserved

Urodynamic assessment of short-term effects of pelvic radiotherapy on bladder function in patients with gynecologic cancers

Objectives: To determine the short-term effects of adjuvant or primary curative radiotherapy (RT) on the urinary system in women with gynecologic cancer. Material and methods: This is a prospective, concurrent cohort study including 55 patients with gynecologic cancer who were divided into three groups. Group 1 included 10 patients who were administered adjuvant RT following a radical hysterectomy (RH); Group 2 included 36 patients who were administered adjuvant RT following a type 1 hysterectomy and Group 3 included 9 patients who were administered primary curative RT. Urogynecologic assessments were carried out on patients before and six months after the treatment. Results: Compared to pretreatment, no significant differences were observed in any of the three groups after treatment in terms of incontinence, first urge to urinate, normal urge to urinate, severe urge to urinate and changes in residual urine volumes. There was a significant decrease in maximal vesical pressure after treatment in Group 1 and Group 3. The maxi­mum detrusor pressure decreased significantly in Group 1. The post-treatment decline in bladder capacity in Group 1 and Group 2 was also significant. Conclusions: RH and pelvic RT cause lower urinary system dysfunction. Especially patients who receive primary curative RT and patients who are administered RT after RH, where more pelvic denervation occurs, are at higher risk due to high doses of RT

Anomalous roughening of wood fractured surfaces

Scaling properties of wood fractured surfaces are obtained from samples of three different sizes. Two different woods are studied: Norway spruce and Maritime pine. Fracture surfaces are shown to display an anomalous dynamic scaling of the crack roughness. This anomalous scaling behavior involves the existence of two different and independent roughness exponents. We determine the local roughness exponents ${\zeta}_{loc}$ to be 0.87 for spruce and 0.88 for pine. These results are consistent with the conjecture of a universal local roughness exponent. The global roughness exponent is different for both woods, $\zeta$ = 1.60 for spruce and $\zeta$ = 1.35 for pine. We argue that the global roughness exponent $\zeta$ is a good index for material characterization.Comment: 7 two columns pages plus 8 ps figures, uses psfig. To appear in Physical Review

Photopatterning of PMMA films with gold nanoparticles: Diffusion of AuCl4 - ions

Photopatterning of poly(methyl methacrylate) (PMMA) films is performed by UV irradiation of the polymer films containing uniformly distributed AuCl 4 - ions. The process reduces the gold ions and leads to production of Au nanoparticles in the irradiated regions at room temperature (RT). Resulting films are investigated with scanning electron microscopy, which revealed, in addition to regions with gold nanoparticles, the presence of "ion-depleted regions". These regions are formed at RT and within the rigid polymer matrix by diffusion of gold ions toward the irradiated regions, ending up with no or very little gold moieties, which are important for prevention of delayed processes for postgeneration of unwanted features, if and when such materials are utilized for device production. Further investigations performed by fluorescence and Raman measurements and XPS mapping give additional evidence supporting the existence of such regions. Similar regions are also observed within the poly(vinyl alcohol) (PVAL) films. The ion-depleted regions are about 10 μm wide, which is a significant length for the metal ions to travel through a rigid matrix like PMMA (or PVAL) at room temperature and raises important questions as to the diffusion mechanism(s) of the metal ions and to the nature of the driving force(s). © 2010 American Chemical Society

Theory of the vortex matter transformations in high Tc superconductor YBCO

Flux line lattice in type II superconductors undergoes a transition into a "disordered" phase like vortex liquid or vortex glass, due to thermal fluctuations and random quenched disorder. We quantitatively describe the competition between the thermal fluctuations and the disorder using the Ginzburg -- Landau approach. The following T-H phase diagram of YBCO emerges. There are just two distinct thermodynamical phases, the homogeneous and the crystalline one, separated by a single first order transitions line. The line however makes a wiggle near the experimentally claimed critical point at 12T. The "critical point" is reinterpreted as a (noncritical) Kauzmann point in which the latent heat vanishes and the line is parallel to the T axis. The magnetization, the entropy and the specific heat discontinuities at melting compare well with experiments.Comment: 4 pages 3 figure