Effect of stoichiometry and milling processes in the synthesis and the piezoelectric properties of modified KNN nanoparticles by solid state reaction

Nanoparticles in the system (K,Na,Li)(Nb,Ta,Sb)O₃, modified KNN, were synthesized following a solid state reaction procedure. Milling of the individual carbonate and oxide raw materials was carried out before mixing of the components to optimize particle size. These mixtures were calcined at 700 °C for 2 h, obtaining nanoparticles with size ranging between 50 and 200 nm. The optimization of the raw materials particle size and the particle refinement of the carbonates during their decomposition play a key role in the formation of the modified KNN nanoparticles by solid state route. The obtained nanoparticles show tetragonal and orthorhombic phases coexistence that could be attributed in part to the lack of homogeneity of cations distribution confirmed by EDS analysis. The K⁺ cation excess on the modified KNN system produces a displacement of Li⁺ cations from the perovskite structure that is the origin of the stabilization of the orthorhombic symmetry. These nanoparticles are used to sintered ceramics with good piezoelectric properties without needing of anisotropic preparation methods. The sintered ceramics show resistance to hygroscopicity and deliquescence.     

The effect of montmorillonite and compatibilizer quantities on stiffness and toughness of polyamide nanoblends

Although polymer blend nanocomposites are widely studied, the balance between stiffness and toughness has not yet been investigated in detail. Some materials producers as well as some sectors in the automotive industry try to improve the toughness of materials without an important loss in stiffness. With this in mind, the aim of the study reported here was to obtain a good balance between toughness and stiffness of polymer blends with different amounts of clay and compatibilizer. In this context, the microstructure of polyamide 6/ethylene–propylene–diene metallocene terpolymer/(ethylene–propylene–diene copolymer)‐graft‐(maleic anhydride) blends with various amounts of clay (2, 3, 4 and 5 wt%) and compatibilizer (10 and 20 wt%) was studied to analyse the achieved morphology to understand the macroscopic properties. The morphology of the rubber phase and the dispersion of the montmorillonite (MMT) are the main factors that influence the mechanical properties. In this sense, the highest Young's modulus is achieved for nanoblends with 5 wt% of MMT, although this nanoblend has the lowest value of notched Izod impact strength. The results obtained suggest that there is a clear trade‐off between stiffness, toughness and temperature behaviour when the ratio of (ethylene–propylene–diene copolymer)‐graft‐(maleic anhydride) to MMT is 5:1. Copyright © 2009 Society of Chemical Industry     

The electronic structure of oxide-supported tungsten oxide catalysts as studied by UV spectroscopy

The UV spectra of tungsten oxide catalysts supported on alumina, titania and zirconia, and on titania–alumina and titania–zirconia mixed oxides are reported and discussed. Evidence is provided for the different electronic structure of supports and catalysts, which could affect the behavior of the tungsten oxide centres in the different cases. On alumina, tungsten oxide centres are “isolated” by the insulating support, while on titania-based materials they are likely in electronic contact with each other and with Ti centres through the support conduction band. In the case of WOx2013;ZrO₂, the 5d levels of tungsten ions fall just below of the lower energy limit of the support conduction band. This revised version was published online in July 2006 with corrections to the Cover Date.     

Selective catalytic transformations of methanol to C2-C3 hydrocarbons over the new zeolite type LZ 132

The small pore zeolite HLZ 132 exhibits, in comparison with other zeolites, an increased selectivity for the transformation of methanol to ethylene in the reaction temperature range 350–500 °C: the weight ratio of C₂H₄ to C₃H₆ in the products ranges between 1 and 4 at WHSV=2 h^–1. Besides the effect of the reactant shape selectivity this fact may be interpreted by the participation of the asymmetrical methoxy groups in the surface as well as by proton-donor centres of lower acidity which do not catalyze the oligomerization of ethylene but which do the more basic molecule of propylene, thereby generating polyene-type coke.     

Depletion of tylosin residues in feathers,muscle and liver from broiler chickens after completion of antimicrobial therapy

Tylosin is one of the most commonly used antimicrobial drugs from the macrolide family and in broiler chickens it is used specially for the treatment of infectious pathologies. The poultry industry produces several by-products, among which feathers account for up to 7% of a chicken’s live weight, thus they amount to a substantial mass across the whole industry. Feathers have been repurposed as an animal feed ingredient by making them feather meal. Therefore, the presence of high concentrations of residues from antimicrobial drugs in feathers might pose a risk to global public health, due to re-entry of these residues into the food chain. This work aimed to characterise the depletion behaviour of tylosin in feather samples, while considering its depletion in muscle and liver tissue samples as a reference point. To achieve this goal, we have implemented and validated an analytical methodology suitable for detecting and quantifying tylosin in these matrices. Sixty broiler chickens, raised under controlled conditions, received an oral dose of 32 mg kg^-1 of tylosin for 5 days. Tylosin was quantified in muscle, liver and feathers by liquid chromatography coupled with a photodiode array detector (HPLC-DAD). High concentrations of tylosin were detected in feather samples over the whole experimental period after completing both the therapy and the recommended withdrawal time (WDT). On the other hand, tylosin concentrations in muscle and liver tissue samples fell below the limit of detection of this method on the first sampling day. Our results indicate that the WDT for feather samples is 27 days, hence using feather meal for the formulation of animal diets or for other agricultural purposes could contaminate with antimicrobial residues either other livestock species or the environment. In consequence, we recommend monitoring this matrix when birds have been treated with tylosin, within the context of poultry farming.     

Nutritional quality and acceptability of a product formulated with mechanically deboned poultry meat,plasma and bovine red cell

The purpose of this research was to evaluate the nutritional quality and acceptability of a meat product formulated with mechanically deboned poultry meat (40%), bovine plasma (40%) and bovine red cells (3%) as major ingredients. Proteins, fat, humidity and ash were determined by AOAC procedure, iron and calcium by Atomic Absorption Spectrometry and essential amino acids by HPLC. Biological evaluation was performed using digestibility and PER procedures. To evaluate the acceptability (flavor, color and odor) of the product were used 277 children. Results indicated that 100 g of the formulated meat product contain 10.7 g of proteins, 4.4 g of fat, 68.6 g of humidity, 2.9 g of ash, 4.9 mg of iron, 46.6 mg of calcium. Essential amino acids are above the FAO requirements for a highly nutritional protein digestibility (92.4%) and PER (2.18). Acceptability was 91.3% for flavor, 81.2% for color and 92.4% for odor. The high nutritional quality and acceptability along with the low cost make this meat product suitable for government social programs.     

GPU fuzzy c-means algorithm implementations: performance analysis on medical image segmentation

Multimedia Tools and Applications - Image segmentation in the medical imagery such as MRI, is an essential step to the sensitive analysis of human tissues lesions with the objective to improve the...     

Nutrient concentration in soil water extracts and soybean nutrition in response to lime and gypsum applications to an acid Oxisol under no-till system

No-till system (NTS) occupies 20 million hectares with grain crops in Brazil. However, calcium deficiency and aluminum toxicity can limit crop yields in many soils, and liming, associated to gypsum application, is an option for improving soil management. The objective of this study was to evaluate the effects of lime and gypsum application on the composition of soil water extracts of a clayey Rhodic Hapludox, cultivated with soybean under NTS. The experiment had a randomized complete block design with split-plots. The plots consisted of lime treatments (either a single rate of 4.5 t ha⁻¹ or three annual rates of 1.5 t ha⁻¹) surface-applied or incorporated at 0.2 m depth. The subplots received surface applications of gypsum (3, 6 and 9 t ha⁻¹). Liming increased total calcium and magnesium concentrations and the magnesium free Form activity (aMg²⁺) in the water extracts. The effect of liming on Mg was observed at deeper layers of the soil profile. Gypsum increased total concentration and free forms activities at calcium (aCa²⁺) and sulfate, but decreased to magnesium in the 0.05–0.2 m soil layer. Part of Mg lost from these upper layers probably contributed to increased Mg in the subsoil (0.4–0.8 m). Free forms activities at the aluminum, calcium, magnesium and sulfate were lower than the total concentrations, mainly for aluminum. Ca and Mg concentrations in soybean leaf tissue were positively correlated to the aCa²⁺ and aMg²⁺ in the soil water extract. Soybean grain yield was negatively correlated to both Mn total concentration and activity (free form) in the soil water extract, but it was positively correlated to sulfate (total concentration and free form activity) in the subsoil layer and to the Ca total concentration in the upper layer (0–0.05 m). It is concluded that lime and gypsum ameliorate soybean grain yield under NTS.