Período de convivência das plantas daninhas com cultivares de feijão-caupi em várzea no Amazonas.

Este trabalho teve o objetivo de determinar o período de convivência das plantas daninhas com três cultivares de feijão-caupi (Vigna unguiculata) em solo de várzea no Estado do Amazonas. A semeadura do feijão-caupi foi em outubro de 2007 no sistema convencional

Seizure Detection, Seizure Prediction, and Closed-Loop Warning Systems in Epilepsy

Nearly one-third of patients with epilepsy continue to have seizures despite optimal medication management. Systems employed to detect seizures may have the potential to improve outcomes in these patients by allowing more tailored therapies and might, additionally, have a role in accident and SUDEP prevention. Automated seizure detection and prediction require algorithms which employ feature computation and subsequent classification. Over the last few decades, methods have been developed to detect seizures utilizing scalp and intracranial EEG, electrocardiography, accelerometry and motion sensors, electrodermal activity, and audio/video captures. To date, it is unclear which combination of detection technologies yields the best results, and approaches may ultimately need to be individualized. This review presents an overview of seizure detection and related prediction methods and discusses their potential uses in closed-loop warning systems in epilepsy

Highly dispersed PTFE/Co3O4 flexible films as photocatalyst showing fast kinetic performance for the discoloration of azo-dyes under solar irradiation

Small nanosized clusters of Co3O4 coated on PTFE (polytetrafluoroethylene) flexible film is reported as a novel supported photocatalyst effective in the fast discoloration of the azo-dye Orange II under simulated solar radiation in the presence of oxone (2KHSO5·KHSO4·K2SO4). The photocatalytic discoloration of Orange II on the PTFE/Co3O4 films proceeds within minutes and the process could be repeated many times without a loss in photocatalyst stability. The photodiscoloration proceeds with a photonic efficiency of ∼1. The PTFE seems to act as a structure forming matrix for the colloidal Co3O4 coated on it surface leading to nanosized clusters of Co3O4. Monitoring the amount of Co2+-ions shows the Co2+-ions from the PTFE/Co3O4 during the photocatalysis enter the solution and at a later are stage re-adsorbed the Co3O4 crystallographic network (∼8 min). By elemental analysis (EA) the loading of Co-loading per cm2 PTFE film was found to vary between 1% and 2%. Transmission electron microscopy (TEM) shows the size of the Co3O4 clusters to vary between 3 and 10 nm. Electron dispersive spectrometry (EDS) confirms the presence of Co on the PTFE. X-ray photoelectron spectroscopy (XPS) of the PTFE/Co3O4 films reveal a partial reduction of the Co3O4 after Orange II discoloration leading to a substantial increase of the amount of Co(II) species in the Co3O4. Physical insight is provided into the catalyst film surface by carrying out Ar-sputtering of the PTFE/Co3O4 surface to remove the catalyst overlayers up to ∼20 nm

Preparation, stabilization and characterization of TiO2 on thin polyethylene films (LDPE): Photocatalytic applications

An innovative way to fix preformed nanocrystalline TiO2 on low-density polyethylene film (LDPE-TiO2) is presented. The LDPE-TiO2 film was able to mediate the complete photodiscoloration of Orange II using about seven times less catalyst than a TiO2 suspension and proceeded with a photonic efficiency of ~0.02. The catalyst shows photostability over long operational periods during the photodiscoloration of the azo dye Orange II. The LDPE-TiO2 catalyst leads to full dye discoloration under simulated solar light but only to a 30% TOC reduction since long-lived intermediates generated in solution seem to preclude full mineralization of the dye. Physical insight is provided into the mechanism of stabilization of the LDPE-TiO2 composite during the photocatalytic process by X-ray photoelectron spectroscopy (XPS). The adherence of TiO2 on LDPE is investigated by electron microscopy (EM) and atomic force microscopy (AFM). The thickness of the TiO2 film is seen to vary between 1.25 and 1.69 mm for an unused LDPE-TiO2 film and between 1.31 and 1.50 mmfor a sample irradiated 10h during Orange II discoloration pointing out to a higher compactness of the TiO2 film after the photocatalysis

Structure and performance of a novel TiO2-phosphonate composite photocatalyst

An innovative SiO2-PO43--TiO2 photocatalyst is presented which is able to bond TiO2 to Raschig rings (RR). Evidence for the formation on the catalyst surface of P = O stretching bands near 1200-1250 cm(-1) is presented by FTIR spectroscopy. The TiO2 Degussa P25 on the catalyst surface (RR) was further characterized by high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction showing that the composite catalyst prepared at 500 degrees C does not alter the particle size or crystallographic composition of the TiO2 Degussa P25 particles. The Ti- and P-distribution of the catalyst surface overlayers was obtained by Ar-sputtering eroding up to 100 topmost catalyst layers. By atomic force microscopy (AFM) the root mean square roughness (Rq) or rugosity of similar to 771 nm and an average height of the catalyst layer of 1.52 mu m were found on the glass surface. The root mean square roughness Rq varies very little in value before and after the photocatalysis indicating that the sample porosity is conserved during 4-CP photodegradation. The disappearance kinetics of 4-chlorophenol (4-CP) on the SiO2-PO43--TiO2 composite occurred within 15 min and was faster than the 45 min needed with suspensions of TiO2 Degussa P25 (1 g L-1). The SiO2-PO43--TiO2 photocatalyst was able to degrade repetitively 4-CP solutions without loss of activity. The effect of the light intensity, oxidant concentration and 4-CP concentration on the photodegradation kinetics was investigated and is reported in this study. (C) 2008 Elsevier B.V. All rights reserved

Direct Compounding Injection Molding and Resulting Properties of Ternary Blends of Polylactide, Polybutylene Succinate and Hydrogenated Styrene Farnesene Block Copolymers

Direct compounding injection molding of ternary blends of polylactide (PLA), polybutylene succinate (PBS) and a hydrogenated styrene farnesene block copolymer (HSFC) was investigated for different blend compositions. Morphological analysis by atomic force microscopy and scanning electron microscopy showed a heterogeneous morphology of the ternary blends, with coexisting droplets of HSFC and PLA respectively PBS. Particle sizes analysis of the minor phases in the ternary blends showed mean values in the range of ∼1 μm, which is discussed in correlation to the rheological properties of the blend components as obtained by high pressure capillary rheometry. In result, with increasing HSFC content, the ternary blends showed a significant increase in notched Charpy impact strength (acN). In concrete, for the ternary blends with 15 wt% of HSFC a maximum acN of 15.8 kJ/m2 was found. At the same time, incorporation of the HSFC resulted only in a moderate reduction in elastic modulus and tensile strength

Blends of photovoltaic-grade ethylene-vinylacetate copolymers and low-density ethylene-octene copolymers, their morphology and their thermal, mechanical, and rheological properties

Blends of photovoltaic‐grade ethylene-vinyl acetate copolymer (EVA), defined by high VA‐content and low crystallinity, and low‐density ethylene-octene copolymer (EO) have been investigated with regard to their processing, thermal and mechanical properties as well as their morphology. It was found that the amount of EO in the blend has a strong influence on the shear thinning behavior, melt viscosity and therefore the required extrusion temperature and resulting ability to incorporate temperature‐sensitive additives like a peroxidic crosslinking agent. A phase separated morphology was found for all blend compositions, though partial miscibility leading to co‐crystallization was observed for EVA rich blends. EO rich blends show lower glass transition and higher melting point compared to neat EVA and exhibit higher elastic modulus at elevated temperatures as well as greater elongation at break during tensile testing while the light transmission is diminished