An experimental study of the partitioning of trace elements between rutile and silicate melt as a function of oxygen fugacity

Subduction zone or arc magmas are known to display a characteristic depletion of High Field Strength Elements (HFSE) relative to other similarly incompatible elements, which can be attributed to the presence of the accessory mineral rutile (TiO2) in the residual slab. Here we show that the partitioning behavior of vanadium between rutile and silicate melt varies from incompatible (~0.1) to compatible (~18) as a function of oxygen fugacity. We also confirm that the HFSE are compatible in rutile, with D(Ta) > D(Nb) >> (D(Hf) >/~ D(Zr), but that the level of compatibility is strongly dependent on melt composition, with partition coefficients increasing about one order of magnitude with increasing melt polymerization (or decreasing basicity). Our partitioning results also indicate that residual rutile may fractionate U from Th due to the contrasting (over 2 orders of magnitude) partitioning between these two elements. We confirm that, in addition to the HFSE, Cr, Cu, Zn and W are compatible in rutile at all oxygen fugacity conditions

Design and implementation of an integrated management system for ochratoxin A in the coffee production chain

n/

Development of a biosponge based on Luffa cylindrica and crosslinked chitosan for Allura red AC adsorption

A new bioadsorbent from Luffa cylindrica and cross-linked chitosan was proposed in the present study. Luffa was used as a natural support medium for chitosan crosslinked with glutaraldehyde (LCsG) and epichlorohydrin (LCsE). Biosponges were applied to remove Allura red from aqueous solutions. LCsG and LCsE were produced using different concentrations of chitosan (1%, 3% and 5% (m v−1)) and crosslinking agents (0.5%, 1.0% and 1.5% (v v−1)). Based on the FT-IR spectra, functional groups characteristic of chitosan crosslinked with glutaraldehyde and epichlorohydrin confirmed the crosslinking. In addition, the biosorbent revealed highly efficient functional groups and morphology with irregularities favorable for adsorption. It was found that the increase in the percentage of glutaraldehyde and epichlorohydrin increased the sample's swelling degree, and the degree of cross-linking was greater than 80% for all LCsG. The results regarding the degree of swelling and degree of crosslinking corroborated with the evaluation of the biosponge's adsorptive potential. The Sips model predicted the equilibrium isotherms, with a maximum adsorption capacity of 89.05 mg g−1 for LCsG and 60.91 mg g−1 for LCsE. The new procedure was successful. Luffa was excellent support for chitosan, resulting in an attractive, low-cost bioadsorbent, preventing renewable sources

Анализ маркетинговых приемов на примере томской сети универсамов "Абрикос"

В данной статье дано новое определение "маркетинговый прием", рассмотрена история развития российского маркетинга, проанализированы "маркетинговые приемы" на примере томской сети универсамов "Абрикос" и даны рекомендации для эффективных и экономных покупок в супермаркетах

Changes in trabecular bone, hematopoiesis and bone marrow vessels in aplastic anemia, primary osteoporosis, and old age

Retrospective histologic analyses of bone biopsies and of post mortem samples from normal persons of different age groups, and of bone biopsies of age- and sex-matched groups of patients with primary osteoporosis and aplastic anemia show characteristic age dependent as well as pathologic changes including atrophy of osseous trabeculae and of hematopoiesis, and changes in the sinusoidal and arterial capillary compartments. These results indicate the possible role of a microvascular defect in the pathogenesis of osteoporosis and aplastic anemia

Unveiling the impact of the effective particles distribution on strengthening mechanisms: A multiscale characterization of Mg+Y2O3 nanocomposites

International audienceMost models used to account for the hardening of nanocomposites only consider a global volume fraction of particles which is a simplified indicator that overlooks the particles size and spatial distribution. The current study aims at quantifying the effect of the real experimental particles spatial and size distribution on the strengthening of a magnesium based nanocomposites reinforced with Y 2 O 3 particles processed by Friction Stir Processing (FSP). X-ray tomographic 3-D images allowed to identify the best FSP parameters for the optimum nanocomposite. A detailed analysis indicates that the observed hardening is mainly due to Orowan strengthening and the generation of geometrically necessary dislocations (GND) due to thermal expansion coefficients (CTE) mismatch between magnesium and Y 2 O 3 particles. A multiscale characterization coupling 3D X-ray laboratory, synchrotron nanoholotomography and transmission electron microscopy (TEM) has been used to investigate particles size and spatial distribution over four orders of magnitude in length scales. Two dedicated micromechanical models for the two strengthening mechanisms are applied on the experimental particle fields taking into account the real particles size and spatial distribution, and compared to classical models based on average data. This required to develop a micromechanical model for CTE mismatch hardening contribution. This analysis reveals that the contribution from CTE mismatch is decreased by a factor two when taking into account the real distribution of particles instead of an average volume fraction

Fine-tuning of functional and structural properties of Ca(II)-alginate beads containing artichoke waste extracts

Artichoke harvest waste is rich in phenolic compounds, which we retrieved with green extractions to exploit this otherwise undervalued material. Here, to protect these labile compounds, we encapsulated the extract into Ca(II)-alginate beads and optimized their physico-chemical and structural properties via response surface methodology. Moreover, we corroborated the carryover of predominant phenolic compounds from waste to bead via high-performance liquid chromatography coupled with diode-array detection and mass spectrometry (HPLC-DAD-MS). We found that maximum bioactive capacity is obtained at higher concentrations of alginate precursor and lower gel consolidation times and that strength, size, and roundness of the beads were influenced mainly by the alginate precursor concentration. Additionally, through small angle X-ray scattering we revealed a deep relationship between synthesis conditions and the microstructure of the gel, related to the crosslinking degree and ramification of the final arrangement, which in turn impacts its strength. We validated the model by running an optimal point of 2 min of gelling time and 2.25 % of alginate and obtaining satisfactory experimental errors for the parameters analyzed. This holistic approach enables modulation and bottom-up tuning of the structure of beads for advanced delivery applications.EEA San PedroFil: Zazzali, Ignacio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica y Departamento de Industrias; ArgentinaFil: Zazzali, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR); ArgentinaFil: Zazzali, Ignacio. Universidad de Buenos Aires. Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR); ArgentinaFil: Jaramillo, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Tecnología de Alimentos y Procesos Químicos (ITAPROQ); ArgentinaFil: Jaramillo, Gabriela. Universidad de Buenos Aires. Instituto de Tecnología de Alimentos y Procesos Químicos (ITAPROQ); ArgentinaFil: Gabilondo, Julieta. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Peixoto Mallmann, Luana. Universidade Federal do Río Grande do Sul. Instituto de Ciência e Tecnologia de Alimentos; BrasilFil: Rodrigues, Eliseu. Universidade Federal do Río Grande do Sul. Instituto de Ciência e Tecnologia de Alimentos; BrasilFil: Perullini, Mercedes. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Perullini, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE); ArgentinaFil: Perullini, Mercedes. Universidad de Buenos Aires. Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE); ArgentinaFil: Santagapita, Patricio R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica y de Industrias; ArgentinaFil: Santagapita, Patricio R. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR); ArgentinaFil: Santagapita, Patricio R. Universidad de Buenos Aires. Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR); Argentin

SSDSS IV MaNGA - Properties of AGN host galaxies

We present here the characterization of the main properties of a sample of 98 AGN host galaxies, both type-II and type-I, in comparison with those of about 2700 non-active galaxies observed by the MaNGA survey. We found that AGN hosts are morphologically early-type or early-spirals. For a given morphology AGN hosts are, in average, more massive, more compact, more central peaked and rather pressurethan rotational-supported systems. We confirm previous results indicating that AGN hosts are located in the intermediate/transition region between star-forming and non-star-forming galaxies (i.e., the so-called green valley), both in the ColorMagnitude and the star formation main sequence diagrams. Taking into account their relative distribution in terms of the stellar metallicity and oxygen gas abundance and a rough estimation of their molecular gas content, we consider that these galaxies are in the process of halting/quenching the star formation, in an actual transition between both groups. The analysis of the radial distributions of the starformation rate, specific star-formation rate, and molecular gas density shows that the quenching happens from inside-out involving both a decrease of the efficiency of the star formation and a deficit of molecular gas. All the intermediate data-products used to derive the results of our analysis are distributed in a database including the spatial distribution and average properties of the stellar populations and ionized gas, published as a Sloan Digital Sky Survey Value Added Catalog being part of the 14th Data Release: http://www.sdss.org/dr14/manga/manga-data/manga-pipe3d-value-added-catalog/Comment: 48 pages, 14 figures, in press in RMxA

About the pulsed current distribution in the massive single-turn solenoid

Криволинейный контур профиля массивного одновиткового соленоида для создания заданного распределения импульсного магнитного поля на цилиндрической поверхности при магнитно-импульсной обработке металлов можно существенно упростить, аппроксимируя многоугольником. Распределение тока вблизи острых кромок таких соленоидов, соответствующих вершинам многоугольника, представляет теоретический и практический интерес. Однако в реальных условиях идеально острые кромки не достижимы и в высоковольтной и сильноточной технике их обычно скругляют, чтобы избежать локального перегрева. Такое скругление может вызывать перераспределение тока. Получены распределения импульсного тока в системе массивный одновитковый соленоид - соосный проводящий цилиндр при помощи численного решения интегрального уравнения для поверхностной плотности тока в приближении идеального поверхностного эффекта. При этом интегральное уравнение аппроксимировали системой линейных алгебраических уравнений на сетке, нанесенной на контур профиля соленоида и образующую цилиндра. Установлено, что аппроксимация точного контура многоугольным ведет к существенному перераспределению тока в соленоиде. Имеет место значительное возрастание поверхностной плотности тока вблизи кромок соответствующих вершинам многоугольника, величина внутреннего угла которых меньше π, и уменьшение поверхностной плотности тока, если величина такого угла больше π. Сделана оценка влияния скругления острых кромок дугами относительно малого радиуса на получаемые распределения поверхностной плотности тока. Показано, что увеличение радиуса скругления приводит к уменьшению максимальной плотности тока вблизи скругляемой кромки, если внутренний угол при соответствующей вершине меньше π. При этом, относительная величина этого уменьшения зависит преимущественно от величины угла и практически не зависит от расположения. Максимальное уменьшение наблюдается вблизи вершин, угол при которых равен π/2: плотность тока уменьшается в 2.5÷4 раза в зависимости от радиуса скругления. Для вершин, угол при которых больше π, характерно увеличение минимальной плотности тока вследствие усиления кольцевого эффекта и эффекта близости.A curvilinear contour of a massive single-turn solenoid for generating a given distribution of pulse magnetic field on the cylindrical workpiece during magnetic pulse forming process can be significantly simplified using approximation by a polygon. The current distribution near the sharp edges of such solenoids is of theoretical and practical interest. However, in real conditions the ideally sharp edges are not achievable. Besides, in high-voltage and high-current equipment they are usually rounded to avoid local overheating. Therefore, the current redistribution may be caused by such rounding. The distributions of pulsed current in system of massive single-turn solenoid and coaxially placed conductive cylinder is received with help of numerical solution of integral equation for surface current density using ideal skin effect approximation