Criticality features in ULF magnetic fields prior to the 2011 Tohoku earthquake

The criticality of ULF (Ultra-low-frequency) magnetic variations is investigated for the 2011 March 11 Tohoku earthquake (EQ) by natural time analysis. For this attempt, some ULF parameters were considered: (1) F_h (horizontal magnetic field), (2) F_z (vertical magnetic field), and (3) D_h (inverse of horizontal magnetic field). The first two parameters refer to the ULF radiation, while the last parameter refers to another ULF effect of ionospheric signature. Nighttime (L.T. = 3 am ± 2 hours) data at Kakioka (KAK) were used, and the power of each quantity at a particular frequency band of 0.03–0.05 Hz was averaged for nighttime hours. The analysis results indicate that F_h fulfilled all criticality conditions on March 3–5, 2011, and that the additional parameter, D_h reached also a criticality on March 6 or 7. In conclusion, criticality has reached in the pre-EQ fracture region a few days to one week before the main shock of the Tohoku EQ.     

Combined Effect of Temperature and Ternary Mobile Phase Composition on the Retention in Ternary Isocratic and Gradient Elution RP-LC under Isothermal Conditions. Application to the Retention Prediction of Four Macrolide Antibiotics

Retention models considering simultaneously ternary mobile phase organic contents and column temperature (T) were developed by a direct combination of equations expressing separately the dependence of the retention upon each of these factors. Thus, a combination of a linear dependence of the logarithm of the solute retention factor, ln k (T), against 1/T, i.e. ln k (T) = a + b/T, and of either a linear or a quadratic dependence of ln k upon the compositions of a binary mobile phase, gave two different expressions for the logarithm of the solute retention factor in terms of both temperature and organic contents in the ternary mobile phase. The effectiveness of the above models was tested in the prediction of isothermal retention of a mixture of four macrolide antibiotics under ternary isocratic and gradient elution conditions using mobile phases modified by methanol and acetonitrile. The limiting case of using ternary eluents with constant ratio of the concentrations of the two organic modifiers was also tested.     

The first use of porphyrins as catalysts in cross-coupling reactions: a water-soluble palladium complex with a porphyrin ligand as an efficient catalyst precursor for the Suzuki-Miyaura reaction in aqueous media under aerobic conditions

For the first time, a palladium complex with a porphyrin ligand is used as a catalyst precursor for cross-coupling reactions. The synthesis of a palladium complex with a phosphine-free and water-soluble potassium carboxylate salt of a porphyrin, and its evaluation in the Suzuki-Miyaura reaction of phenylboronic acid with aryl bromides (from electron-rich to electron-poor), in neat water, under aerobic conditions is described. Catalysis is performed at 100 °C for 4 h, using K₂CO₃ as base, and a substrate to catalyst molar ratio of 1000:1, leading to yields of coupling products in the range of 80-100%. The catalyst can be recycled and reused, but unfortunately, with a loss in activity.     

Impact of Statistical Multiplexing on Voice Quality in Cellular Networks

This paper examines the quality of transmission of voice over cellular, packet-switched networks. The medium access mechanism in the uplink is simulated under various statistical multiplexing scenarios in order to assess the effect of front-end clipping on voice quality. Moreover, the simulation is implemented in a real-time demonstration platform utilized to acquire subjective indicators of voice quality by performing Mean Opinion Score (MOS) tests. Results from the MOS tests are reported, and an analysis of the obtained speech samples is presented. Finally, the results are summarized and potential further directions for the simulation tool and the speech models are discussed.     

High resolution multigrid cross-correlation digital PIV measurements of a turbulent starting jet using half frame image shift film recording

This paper describes a novel approach of acquiring two single-exposed, non-overlapping images using half frame image shift (HFIS) recording on photographic film. This technique permits the recording of two single-exposed, non-overlapping images of seed particles in a flow plane on high spatial resolution film with any arbitrary time delay between exposures. A new multigrid CCDPIV (MCCDPIV) analysis method is used to analyse the single-exposed, non-overlapping sequential images resulting in PIV measurements with a larger velocity dynamic range, lower random error and better spatial resolution than standard CCDPIV analysis. HFIS recording followed by MCCDPIV analysis was employed to measure the spatio-temporal evolution of the in-plane velocity vector and the out-of-plane vorticity fields of a turbulent starting jet at Reynolds numbers based on the orifice diameter and piston velocity of 10,780 and 13,860.     

Emerging nanocomposite biomaterials as biomedical adsorbents: an overview

Abstract

Biomedicine and pharmacy identify highly important scientific fields within the present time. However, increased advancements in these sciences have influenced the identification of increased levels in environmental degradation through pollution. Pharmaceutical production has influenced increased scientific and public concern regarding the increasing rate of pollution attributed to high levels of toxicological properties within the products. Pharmaceutical compounds are not fully removed through the integration of wastewater treatment plants (WWTP). This renders pharmaceutical compounds, municipal effluents together with hospitals as the major culprits in the development of the majority of the sources that enhance environmental degradation. A wide range of the compounds have been the identified within WWTP effluents, surface water together with ground and drinking water on a global scale. All above has influenced the research development in technological field developing new ways for efficient removal of pharmaceuticals from wastewater produced from the pharmaceuticals or biomedical industries. This situation may be altered through the utilization of adsorbents. Therefore more studies have been published investigating the use of nanocomposite biomaterials for removing the pharmaceutical compounds existing in biomedical effluents.     

Magnetohydrodynamics and Plasma Cosmology

We study the linear magnetohydrodynamic (MHD) equations, both in the Newtonian and the general-relativistic limit, as regards a viscous magnetized fluid of finite conductivity and discuss instability criteria. In addition, we explore the excitation of cosmological perturbations in anisotropic spacetimes, in the presence of an ambient magnetic field. Acoustic, electromagnetic (e/m) and fast-magnetosonic modes, propagating normal to the magnetic field, can be excited, resulting in several implications of cosmological significance.