Mechanochemical Synthesis of Visible Light Sensitive Titanium Dioxide Photocatalyst

Phase transition of anatase nanoparticles into the phases TiO2-II and rutile under grinding was studied. The addition of ammonium carbamate to the reaction mixture inhibits the phase conversion and the cold welding of particles. The UV-visible absorption spectrum showed narrowing the band gap width after grinding with an ammonium carbamate additive resulting in shift of the light absorption of the ground sample towards the visible region. By EPR, intensive formation of OH• radical at irradiation of the sample with both UV (λ > 300 nm) and visible (λ > 435 nm) light was observed. High photocatalytic activity of the ground sample in visible light region was demonstrated also by measurement of kinetics of the photocatalytic decomposition of 4-chlorophenol

CLADOBOTRYUM MYCOPHILUM, CAUSAL AGENT OF COBWEB DISEASE ON COMMERCIAL AGARICUS BISPORUS AND PLEUROTUS ERYNGII CROPS IN SPAIN

ABSTRACT Between 2008 and 2011, outbreaks of cobweb were observed in commercial white button and king oyster mushroom crops in Castilla-La Mancha (Spain) based on morphological and genetic analysis the casual agent was identified as Cladobotryum mycophilum. Two Agaricus bisporus mushroom cropping trials inoculated with C. mycophilum were performed. The total area of the crop affected by cobweb was 30% in the inoculated blocks of trial A and 45% in trial B. The non-inoculated blocks remained healthy. Compared with the uninoculated controls, a decrease in the yield of 10.7% was observed in trial A and 9.1% in trial B. Pathogenicity trial was also performed using blocks containing sterilized, spawned and incubated P. eryngii substrate. The first cobweb symptoms developed 23 days after inoculation and C. mycophilum was consistently re-isolated from nine (37.5%) of the inoculated blocks. Non-inoculated blocks remained healthy. In a second test, conidial suspensions of three isolates of C. mycophilum were inoculated onto P. eryngii fruit bodies. C. mycophilum grew between 80 and 85% of the inoculated fruit bodies, while the control fruit bodies remained symptomless

Non-isothermal Characterization of the Precipitation Hardening of a Cu-11Ni-19Zn-1Sn Alloy

The precipitation hardening of a Cu-11Ni-19Zn-1Sn alloy has been studied by means of Differential Scanning Calorimetry (DSC), High-Resolution Transmission Electron Microscopy (HRTEM), and hardness measurements. The calorimetric curves, in the range of temperatures analyzed, show the presence of one exothermic reaction followed by an endothermic one. The exothermic DSC peak is due to the segregation of Cu2NiZn precipitates and it is associated to a noticeable improvement of the mechanical properties of the alloy. The endothermic effect is associated to the dissolution of the Cu2NiZn precipitates into the copper matrix for restoring the starting Cu-11Ni-19Zn-1Sn homogeneous solid solution. The reaction mechanisms of these processes have been proposed from the kinetic analysis of the exothermic and endothermic DSC signals. The results obtained point out that tin plays a decisive role on the precipitation hardening of the alloy, because age hardening is not observed in the case of a Cu-Ni-Zn ternary alloy of similar composition

Production of Ag−ZnO powders by hot mechanochemical processing

Ag–CdO composites are still one of the most commonly used electrical contact materials in low-voltage applications owing to their excellent electrical and mechanical properties. Nevertheless, considering the restriction on using Cd due to its toxicity, it is necessary to find alternative materials that can replace these composites. In this study, the synthesis of Ag−ZnO alloys from Ag−Zn solid solutions was investigated by hot mechanochemical processing. The hot mechanochemical processing was conducted in a modified attritor mill at 138 °C under flowing O 2 at 1200 cm 3 /min for 3.0 h. The microstructure and phase evolution were investigated using X-ray diffractometry, field emission gun scanning electron microscopy and transmission electron microscopy. The results suggest that it is possible to complete the oxidation of Ag−Zn solid solution by hot mechanochemical processing at a low temperature and short time. This novel synthesis route c

Microcalorimetry: A powerful tool for quantitative analysis of aging hardening response of Cu-Ni-Sn alloys

The method for the deconvolution of overlapping DSC peaks here proposed has been used by the first time for the quantitative determination of the enthalpies associated to the phase transitions undergone during the aging of an alloy. They have been determined the enthalpies evolved along the first and the second overlapping DSC traces of Cu-10 wt%Ni-5.5 wt%Sn alloy, which are associated, respectively, to the spinodal decomposition of the alloy and the segregation of a DO22 (CuxNi1-x)3Sn tetragonal phase. The fraction of the DO22 phase (responsible of the aging hardening of this alloy) has been successfully determined from DSC as a function of the annealing treatment, while TEM and XRD failed for this purpose. It has been demonstrated that a threshold higher than 50% of crystallization of the DO22 phase is required for achieving a significant increase of the hardness as a function of the crystallization percentage. These results suggest that microcalorimetric measurement can be a powerful tool to establish quantitative relationships between the mechanical, electrical or functional properties of alloys and their structural changes undergone by aging

Genetic Analysis and In Vitro Enzymatic Determination of Bacterial Community in Compost Teas from Different Sources

16 páginas.-- 2 figuras.-- 5 tablas.-- 53 referenciasCompost tea has been used throughout the world to control diseases and promote the growth of plants. The microbial community is the main factor involved both in the antagonistic effect against relevant phytopathogens and as a stimulator of plant growth. The objective of this research is to determine the bacterial diversity present in four types of compost as well as some of the mechanisms that may be involved in the positive effects of compost tea on crops. Aerated (ACT) and non-aerated (NCT) compost teas were obtained from four different composts: spent mushroom substrate compost (SMC), grape marc compost (GMC), greenhouse horticultural crop residues compost (CRC), and vermicompost (CRV). 16S rDNA-based DGGE profiles were obtained for each compost tea and their respective bacterial communities were analyzed. Of the 100 clones obtained, those typical for being dominant for all profiles were chosen. In total, 20 different clones were sequenced. The results showed that the bacterial communities of most compost teas had high richness, diversity, and evenness values, with relative abundance of species belonging to Bacteroidetes and Proteobacteria. The NCTs obtained from all the composts, especially CRC and CRV, showed high levels of siderophore production, while teas from GMC manifested high and consistent cellulase activity. The ACTs from all the composts, especially SMC, had high protease activityThe present work benefited from the input of the project RTA2010-00011-C02-02. “Caracterización microbiológica y optimización de los mecanismos de supresividad de sustratos postcultivos de hongos comestibles frente a enfermedades del champiñón, ” from Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) supported by the Spanish Ministry of Science and Innovation.Peer reviewe

Microbiota fúngica asociada a las podredumbres radiculares del puerro cultivado en Villena

Se presenta en este trabajo un estudio sobre la etiología de las podredumbres radiculares del puerro. El estudio abarca los análisis practicados a 825 plantas producidas en semilleros con sustratos a base de turba y bandejas alveoladas y a 310 plantas procedentes de diferentes parcelas en producción del campo de Villena. Las raíces de las plantas, tanto las producidas en semillero como las del campo mostraban, fundamentalmente, una podredumbre blanda que a veces, adquiría coloración marrón clara o rosada, cualquiera que fuese la variedad del puerro (Lancelot, Nepal y Sabina). Dieciséis especies o géneros de hongos fueron aislados, sobresaliendo por su frecuencia: Fusarium moniliforme (F. verticillioides), F.oxysporum, F. roseum, F.solani, Macrophomina phaseolina, Phoma sp., Pythium sp., Rhizoctonia solani, Stemphylium botryosum. Un total de 49 aislados de los hongos mencionados fueron inoculados en plántulas de tres variedades de puerro (Lancelot, Nepal y Sabina) en condiciones ambientales controladas en una cámara climatizada. Ningún síntoma de los observados en campo fue reproducido en las 3528 plantas inoculadas mediante tres técnicas diferentes. El artículo presenta una explicación posible para las podredumbres radiculares estudiadas, basadas en las técnicas de producción de plantas en semilleros, utilizando bandejas alveoladas con sustrato a base de turba y la consiguiente forma de manejar el cultivo en el terreno de asiento al aire libr

Mercado actual para los profesionales del periodismo en la Región Metropolitana y su tendencia a 1998

In this work, a mechanochemical procedure is proposed as a simple and fast method to synthesize the pure BiFeO3 perovskite phase as a nanostructured material without the need for purification treatments, while the mechanochemical reaction mechanism has been investigated and correlated with that of the conventional solid-state reaction. Thus, different milling conditions have been used as a tool for tailoring the crystallite size of the resulting BiFeO3 nanoparticles. The materials prepared by the mechanochemical reaction could be annealed or sintered without the formation of undesirable phases. Both the ferroelectric and ferromagnetic transitions were observed by DSC. Finally, the dielectric constants of the prepared material at different frequencies as a function of the temperature have been measured, showing that the material is clearly an isolator below 200 °C, characteristic of a high quality BiFeO3 material.Gobierno de España CTQ 2011-27626Junta de Andalucía TEP-03002, TEP-785