Quantitative determination of modal content and morphological properties of coal sulphides by digital image analysis as a tool to check their flotation behaviour

An efficient depression of coal sulphides in the flotation process means a healthier environment and may be essential for the sustainability of a coal operation. Nitric and ferric oxidative pre-treatment of coal pyrite have been tested to improve pyrite depression, and the results are compared with those from the process of raw, not pre-treated coal. The removal indexes point to nitric pre-treatment as the best, but depression is still low. The microscopic study of feed and products, coupled to Digital Image Analysis (DIA) in all the cases, provide important clues to understand the behaviour of pyrite, which can be related to quantitative parameters, such as the exposition ratio (ER), and to qualified interpretation of the textures. Pyrite shows in the first float an unexpected hydrophobic behaviour, which is due to its occurrence as framboids, or porous particles which may be intergrown with organic matter and behave as coal. In general, the flotation results can be predicted from the DIA-data, e.g. depression of liberated pyrite into the tailings, increased by oxidative pre-treatments by 300% (ferric) or by > 400% (nitric); or concentration of middlings with lower pyrite ER in the floats. DIA is an efficient tool to obtain some important quantitative informations which otherwise would be inaccessible (e.g. the morphological data on > 1,000,000 pyrite particles for this study), and its use should be enhanced to check ore processing

GEOMETRICAL STRING and DUAL SPIN SYSTEMS

We are able to perform the duality transformation of the spin system which was found before as a lattice realization of the string with linear action. In four and higher dimensions this spin system can be described in terms of a two-plaquette gauge Hamiltonian. The duality transformation is constructed in geometrical and algebraic language. The dual Hamiltonian represents a new type of spin system with local gauge invariance. At each vertex $\xi$ there are $d(d-1)/2$ Ising spins $\Lambda_{\mu,\nu}= \Lambda_{\nu,\mu}$, $\mu \neq \nu = 1,..,d$ and one Ising spin $\Gamma$ on every link $(\xi,\xi +e_{\mu})$. For the frozen spin $\Gamma \equiv 1$ the dual Hamiltonian factorizes into $d(d-1)/2$ two-dimensional Ising ferromagnets and into antiferromagnets in the case $\Gamma \equiv -1$. For fluctuating $\Gamma$ it is a sort of spin glass system with local gauge invariance. The generalization to $p$-branes is given.Comment: 16 pages,Late

Quiste odontogénico calcificante asociado con odontoma complejo: presentación de un caso y revisión bibliográfica

Se presenta un caso de quiste odontogénico calcificante asociado con odontoma (QOCaO) y con un canino permanente incluido en maxilar superior, en un paciente varón de 19 años. El Quiste Odontogénico Calcificante (QOC) fue descrito por primera vez cómo una entidad patológica por Gorlin y col. en 1962. Se trata de un tumor benigno odontogénico mixto,y aunque la mayoria de estas lesiones presentan características quísticas en algunos casos se presenta como una masa sólida (15 %), y su transformación maligna está bien documentada. El QOC se presenta en ocasiones asociado a otros tumores odontogénicos, el más común es el odontoma al que aparece relacionado en el 24% de los casos. Para esta asociación se ha sugerido el término de 'Quiste Odontogénico Odontocalcificante'. Radiológicamente es una lesión mixta, bien definida y que histológicamente consiste en un gran quiste en cuya parte central existe un área sólida con acúmulos de esmalte y dentina distribuidos irregularmente en algunas zonas y en otros lugares adopta un aspecto organoide bien definido. Se efectúa una revisión de la literatura y se discute su patogénesis.We report a calcifying odontogenic cyst associated with odontoma (COCaO) and an included permanent canine in the superior maxilla, in a 19 year-old-man. The calcifying odontogenic cyst (COC) was first described as a distinct entity by Gorlin et al in 1962. The lesion is a mixed odontogenic benign tumor, and although most of the cases present cystic characteristics, a few are of the solid type (15%), and its rare malignant transformation is well documented. The COC may occur in association with other odontogenic tumors, the most common is the odontoma, occurring in about 24% of the cases. For this association the term Odontocalcifying odontogenic cyst has been suggested. Radiographically is a well defined mixed lesion and histologically consists of a large cyst. In the central area of the cyst enamel and dentin deposits can be found, irregularly distributed in areas and in other parts it takes on a well defined organoid aspect. A thorough review of literature takes place and the pathogenesis is discussed

Boron doped TiO2 catalysts for photocatalytic ozonation of aqueous mixtures of common pesticides: Diuron, o-phenylphenol, MCPA and terbuthylazine

Photocatalysts were characterized by ICP-EOS, N2 adsorption-desorption, XRD, XPS, and DR-UV-Vis spectroscopy. Four recalcitrant herbicides and pesticides (diuron, o-phenylphenol, 2-methyl-4-chlorophenoxyacetic acid (MCPA) and terbuthylazine) were subjected to degradation by ozonation, photolytic ozonation, photocatalysis and photocatalytic ozonation using the prepared catalysts under simulated solar irradiation in a laboratory scale system. The boron that was not incorporated to the TiO2 interstitial positions was unstable and leached to the solution. The washed B-doped TiO2 catalysts, with 0.5-0.8 wt.% of interstitial boron were more active than bare TiO2 for the removal and mineralization of the target compounds. The combination of ozonation and photocatalysis led to faster mineralization rates and allowed the complete removal of the pesticides below the regulatory standards. The B-doped catalyst was stable and maintained 75% mineralization after 3 consecutive runs

Novel glassy behavior in a ferromagnetic p-spin model

Recent work has suggested the existence of glassy behavior in a ferromagnetic model with a four-spin interaction. Motivated by these findings, we have studied the dynamics of this model using Monte Carlo simulations with particular attention being paid to two-time quantities. We find that the system shares many features in common with glass forming liquids. In particular, the model exhibits: (i) a very long-lived metastable state, (ii) autocorrelation functions that show stretched exponential relaxation, (iii) a non-equilibrium timescale that appears to diverge at a well defined temperature, and (iv) low temperature aging behaviour characteristic of glasses.Comment: 6 pages, 5 figure

Numerical simulation of strongly nonlinear and dispersive waves using a Green-Naghdi model

We investigate here the ability of a Green-Naghdi model to reproduce strongly nonlinear and dispersive wave propagation. We test in particular the behavior of the new hybrid finite-volume and finite-difference splitting approach recently developed by the authors and collaborators on the challenging benchmark of waves propagating over a submerged bar. Such a configuration requires a model with very good dispersive properties, because of the high-order harmonics generated by topography-induced nonlinear interactions. We thus depart from the aforementioned work and choose to use a new Green-Naghdi system with improved frequency dispersion characteristics. The absence of dry areas also allows us to improve the treatment of the hyperbolic part of the equations. This leads to very satisfying results for the demanding benchmarks under consideration

Synthesis of BiOI/Mordenite Composites for Photocatalytic Treatment of Organic Pollutants Present in Agro-Industrial Wastewater

Recently, bismuth oxyiodide (BiOI) is an attractive semiconductor to use in heterogeneous photocatalysis processes. Unfortunately, BiOI individually shows limited photocatalytic efficiency, instability, and a quick recombination of electron/holes. Considering the practical application of this semiconductor, some studies show that synthetic zeolites provide good support for this photocatalyst. This support material permits a better photocatalytic efficiency because it prevents the quick recombination of photogenerated pairs. However, the optimal conditions (time and temperature) to obtain composites (BiOI/ synthetic zeolite) with high photocatalytic efficiency using a coprecipitation-solvothermal growth method have not yet been reported. In this study, a response surface methodology (RSM) based on a central composite design (CCD) was applied to optimize the synthesis conditions of BiOI/mordenite composites. For this purpose, eleven BiOI/mordenite composites were synthesized using a combined coprecipitation-solvothermal method under different time and temperature conditions. The photocatalytic activities of the synthesized composites were evaluated after 20 min of photocatalytic oxidation of caffeic acid, a typical organic pollutant found in agro-industrial wastewater. Moreover, BiOI/mordenite composites with the highest and lowest photocatalytic activity were physically and chemically characterized using nitrogen adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and diffuse reflectance spectroscopy (DRS). The optimal synthesis conditions prove to be 187 °C and 9 h. In addition, the changes applied to the experimental conditions led to surface property modifications that influenced the photocatalytic degradation efficiency of the BiOI/mordenite composite toward caffeic acid photodegradation

Galaxy rotation curves: the effect of j x B force

Using the Galaxy as an example, we study the effect of j x B force on the rotational curves of gas and plasma in galaxies. Acceptable model for the galactic magnetic field and plausible physical parameters are used to fit the flat rotational curve for gas and plasma based on the observed baryonic (visible) matter distribution and j x B force term in the static MHD equation of motion. We also study the effects of varied strength of the magnetic field, its pitch angle and length scale on the rotational curves. We show that j x B force does not play an important role on the plasma dynamics in the intermediate range of distances 6-12 kpc from the centre, whilst the effect is sizable for larger r (r > 15 kpc), where it is the most crucial.Comment: Accepted for publication in Astrophysics & Space Science (final printed version, typos in proofs corrected

Efficacy, safety and patient reported outcomes (PROS) in adult patients with atopic dermatitis treated with dupilumab at week-52 in usual clinical practice

P15 Background: Dupilumab, an anti-interleikin-4-receptor-a monoclonal antibody, is a new treatment for atopic dermatitis in adults. Objective: To evaluate – at week 52 – patient reported outcomes, satisfaction, efficacy and safety, with dupilumab in adult patients with moderate-to-severe atopic dermatitis refractory to the usual treatments previously performed under conditions of usual clinical practice. Methods: Twelve patients were enrolled. Patients from our hospital, under routine clinical practice, were treated with subcutaneous dupilumab 300 mg every 2 weeks. The outcomes were evaluated at baseline, week 4, 8, 12, 16, 28 , 40 and week 52. The variables evaluated were: itch, difficulty to sleep, previous stressful life events, severity (SCORAD), anxiety and depression symptoms (HADS), quality of life (DLQI, EQ5D3L), satisfaction, adherence to the treatment, efficacy and safety. Results: At week 52 significant improvement was observed in severity, itch, difficulty to sleep, anxiety and depression symptoms, and quality of life. Satisfaction with dupilumab compared to previous treatments was significantly higher in all aspects assessed. No significant dupilumab-induced laboratory abnormalities were noted, and adverse events were mild and transient. Conclusions: Dupilumab used under routine clinical practice for 52 weeks improved atopic dermatitis signs and symptoms, with a good safety profile and patient satisfaction