Film stimulating coatings for seeds based on silica mixtures

For improve the quality of harvests, modern farms in many countries widely use fertilizers of mineral and natural origin. To mitigate the negative impact on the environment, they try to minimize the amount of mineral fertilizers applied to the soil by creating composite systems. In particular, powdered composite materials are known based on highly dispersed silica and microquantities of mineral fertilizers, which are applied to the surface of the seeds by dusting. The aim of this work was to develop a new generation of film stimulating coatings based on mixtures of hydrophobic AM-1-300 and hydrophilic A-300 silicas, mineral fertilizers and bioactive components. Mixtures of hydrophilic and hydrophobic silicas in the ratio 1:1 and 1:2 were used to obtain a pasty composite with the given stimulating properties; colloidal starch solution; medium salts of mineral acids, bioactive components “Humifriend” and fungicide “Fital”. Such composite systems were applied directly to the surface of sowing material, grains of wheat variety “Natalka” before sowing in sand and on filter paper, according to DSTU 4138-2002. During the study, the following parameters were measured: seed germination energy, germination and morphological characteristics of wheat germs, which consisted in measuring the length of the root and stem. It is shown that when editing certain amounts of bioactive components to the composition of stimulating pasty composites, it is possible to program the properties of future films and powders: to increase morphological characteristics, uniformity of germination and fungicidal characteristics of composites. It has been found that the presence of mineral fertilizers in pasty composites of silicas mixtures 1:1 and 1:2 has a positive effect on the uniform germination of wheat seeds in the sand and on the filter paper. Instead, the presence in the pastes of the active ingredients “Fital” and “Humifriend”, regardless of the environment where the seeds germinated, there is a significant slowdown in the growth of wheat germ in both environments. It has been found that an excess of hydrophilic silica in the pasty composite leads to the development on the surface of the grains of mycosis lesions, regardless of the germination environment. Therefore, stimulant pastes based on 1:2 silica mixtures must contain fungicides of mineral or biological origin.

The Influence of Thermal Sprayed Coats Chemical Composition on the Microstructure and Properties

In the present work, the microstructure, phase composition and microhardness of Cr3C2-NiCr, WCCo, and powdered composite NiCrSiBCr10%,Fe2.5%,Si3.1%,Bi2.1%C; NiCrSiBFe5; NiCrSiBCr5; NiCrSiBFe2.5Cr2.5; HVOF coatings applied on the Al-Si substrate have been compared. The coating cross-sections were examined by optical microscopy (OM), scanning electron microscopy (SEM) and electron transmission microscopy (TEM). For hard Cr3C2-NiCr and WC-Co coatings, a total microhardness level of about 860 and 1240 HV, respectively, was obtained. The microhardness of composite coatings was essentially lower and comprised in the range of values between 420 and 540 HV. The lowest level of microhardness showed the NiCrSiBFe2.5Cr2.5 coating. The most refined microstructure was found in Cr3C2 and WC coatings. The mean size of splat granules obtained in Cr3C2-NiCr had the value of about 2.7 m and of 0.5 m in WC-Co. For comparison, the granules obtained in composite coatings had the dimensions of about 30 μm. An Xray diffraction (XRD) revealed the presence of Cr3C2 and WC carbides in Cr3C2-CrNi and WC-Co coatings. In composite coatings, the phases of Cr3Ni5Si2, Ni3Si, FeSi, Fe2B, Cr3Si, BCr as well as other phases were found. The existence of the analyzed phases was additionally confirmed by the selective etching of coating microstructure. The annealing of coatings at 823K resulted in pore disappearance and increased the coating microhardness.

Manufacture of Sheets Using Post-Consumer Unsaturated Polyester Resin/Glass Fibre Composites

The storage of post-consumer unsaturated polyester/glass fibre composites impacts negatively on the environment due to its persistence (long lifetime of both the glass fibre and the resin) as well as the high volume/weight ratio of the residues. In this work we introduce a new approach for the recycling process of artefacts made of these polyester/glass fibre composites that involves the dispersion of the ground, not powdered, composite in raw polyester resin. Room temperature resin curing was employed. Flexural and impact tests were performed to optimize the processing conditions and the manufacturing process. Significant improvement in texture, flexural strength and impact resistance of sheets were achieved by pressing and heating the sheets at 40∞C and 50∞C during curing. The artefacts utilized in our work were post-consumer public telephone weather protector caps, which, in Brazil, are manufactured with a composite of unsaturated polyester/glass fibre. Although we used this specific artefact, the methodology can be extended to different types of post-consumer materials or industrial scraps.

Normal Phase Liquid Chromatographic Determination of Sulfamethoxazole in Tablets: Collaborative Study

A stability-indicating liquid chromatographic method is presented for determining sulfamethoxazole in tablets. The method uses a 10 p.m silica column, an isooctane-methylene chloride-2-propanol-acetonitrile- glacial acetic acid (70 + 25 + 5 + 5 + 0.5) mobile phase, and photometric detection at 254 nm. Seven laboratories collaboratively studied this method on powdered composite samples prepared from commercial 500 and 1000 mg tablets and on an authentic tablet mixture containing 83.32% added sulfamethoxazole. Mean assay results for the 500 and 1000 mg tablets w ere 102.2 and 97.9% of declared, respectively (n = 4). The mean recovery value for the synthetic sample was 99.4% (n = 4). The pooled reproducibility standard deviation (SD) (coefficient of variation (CV) ) and pooled repeatability SD (CV) were ± 1.01 (1.01%) and ± 0.96 (0.96%), respectively. These results were in good agreement with those obtained by the Associate Referee for the titration method of USP XX. The proposed method can also be used for monitoring the presence of sulfanilamide in sulfamethoxazole by increasing the proportions of both acetonitrile and 2-propanol in the mobile phase. The method has been adopted official first action.