Search results for "Class"
showing 10 items of 38174 documents
Apparent and quantitative loss of fatty acids and triacylglycerols at frying temperatures
2012
[EN]: Olive and sunflower oils were heated at 180 °C for 5, 10 and 15 hours with the aim of defining the changes in the contents of fatty acid methyl esters (FAME) and triacylglycerols (TAG) under frying conditions. Differences between apparent and real loss of FAME or TAG are defined for an adequate interpretation of the changes taking place at high temperature. Such differences depend on the expression of the results and frequently result in erroneous conclusions. Results showed that from the normalized composition it could be deduced that only the most unsaturated FAME (C18:2) or TAG containing it was significantly altered. However, quantitative data indicated that all the unsaturated FA…
Uusia käytäntöjä rakentamassa? : poliisi yhteistyön tekijänä kotouttavassa työssä
2019
Monialainen yhteistyö on yksi keskeinen työmenetelmä kotouttavassa työssä. Monialaisuus viittaa viranomaisten rinnalla järjestökentän, kieli- ja kulttuuritaustaisten yhteisöjen sekä yksityissektorin osallisuuteen yhteistyössä. Myös poliisi on yhtenä toimijana paikallisessa, monialaisessa yhteistyössä kotoutumisen edistämiseksi. Mutta mitä tämä yhteistyö on käytännössä poliisin työn näkökulmasta? Mitä poliisilta heidän nähdäkseen odotetaan ja millaista lisäarvoa poliisi kokee voivansa tuoda yhteistyöhön? Tämä artikkeli kuvailee poliisien kokemuksia yhteistyöstä perustuen väitöskirjatutkimuksen haastatteluaineistoon, joka on koottu neljän poliisilaitoksen alueelta Suomessa. Poliisityötä lähes…
Design of New Polyaspartamide Copolymers for siRNA Delivery in Antiasthmatic Therapy
2020
Here, a novel protonable copolymer was realized for the production of polyplexes with a siRNA (inhibitor of STAT6 expression in asthma), with the aim of a pulmonary administration. The polycation was synthesized by derivatization of &alpha
Application of polydopamine functionalized zinc oxide for glucose biosensor design
2021
Zinc oxide (ZnO) nanostructures are widely used in optical sensors and biosensors. Functionalization of these nanostructures with polymers enables optical properties of ZnO to be tailored. Polydopamine (PDA) is a highly biocompatible polymer, which can be used as a versatile coating suitable for application in sensor and biosensor design. In this research, we have grown ZnO-based nanorods on the surface of ITO-modified glass-plated optically transparent electrodes (glass/ITO). Then the deposition of the PDA polymer layer on the surface of ZnO nanorods was performed from an aqueous PDA solution in such a way glass/ITO/ZnO-PDA structure was formed. The ZnO-PDA composite was characterized by S…
Comparative Investigation on the Soil Burial Degradation Behaviour of Polymer Films for Agriculture before and after Photo-Oxidation
2020
Polymer films based on biodegradable polymers, polyethylene (PE) and modified PE with oxo-degradable additive were prepared by film blowing. Carbon black (1%) was added to all the films. Commercial biodegradable Ecovio®
On the effectiveness of different additives and concentrations on the re-building of the molecular structure of degraded polyethylene
2006
Mechanical recycling is an easy and economic way to re-use plastic waste as secondary materials, but, in general, their properties are worse with respect to the reclaimed materials and the virgin polymer. The aim of this work was to study the effect of concentration and reaction kinetics of two additives, an ethylene-co-glycidyl methacrylate (Lotader) and a hydroxylamine derivative (CGX), in the re-building of a degraded polyethylene. CGX is a nitroxyl radical generator able to form branching in polyolefins while the epoxy groups of Lotader can react with the functional groups present in the recycled polyethylene. The results indicate that the CGX has a higher reaction rate than Lotader, pr…
Effect of sample preparation on gel permeation chromatography results of determination of molecular weight of polyethylene obtained with using of zir…
2003
Molecular weights of polyethylene (PE) obtained with using of zirconocene catalyst activated with large excess of methylaluminoxane (MAO) were determined by gel permeation chromatography (GPC) method. It was found that repeatability of the measurements is strongly influenced by MAO remained in PE samples as well as time of sample keeping in the apparatus (dissolution + measurement time) at temp. 142 °C. A method of MAO removing from PE samples, before GPC measurement, based on additional washing of the sample with HF in methanol solution has been proposed. This modification leads to better both authenticity and repeatability of the results. Studies on the influence of time of sample keeping…
Effect of immobilization of titanocene catalyst in aralkyl imidazolium chloroaluminate media on performance of biphasic ethylene polymerization and p…
2012
1-(2-Phenylethyl)-3-methylimidazolium and 1-benzyl-3-methylimidazolium chloroaluminates, [Ph-C2mim][AlCl4] and [Bzlmim][AlCl4], were applied as media of the Cp2TiCl2 catalyst for biphasic ethylene polymerization. The studied aralkyl ionic liquids ensure greater stability of the catalyst at higher temperatures and more regular morphology of the produced polyethylene than analogous 1-n-alkyl-3-methylimidazolium chloroaluminates. The alkylaluminium compound participates in the termination reaction of the polymer chain. The catalyst is stable and enables recycling of the ionic liquid phase in the consecutive polymerization reactions. The [Ph-C2mim][AlCl4] ionic liquid and AlEt2Cl alkylaluminium…
Weathering of low-density polyethylene grafted with itaconic acid in laboratory tests
2011
Polyethylene grafted with itaconic acid was subjected to weathering under laboratory accelerated conditions. The course of the photo-oxidative degradation process of that material was studied by FTIR spectroscopy both through quantitative measurements of changes in absorbance values at selected wave numbers and through measurements of surface area values for absorption bands which were separated by means of deconvolution. The use of both those procedures of quantitative determinations resulted in a general conclusion that the oxidation process was initiated from the very first moment of irradiation, and it produced ketones, acids, esters (intramolecular and of acetate type), peracids, peres…
Influence of accelerated ageing conditions on the process of polyolefines degradation
2003
The process of polymers weathering and the methods of polymers weathering and accelerated ageing investigations were characterized. Accelerated ageing tests of polyethylene and polypropylene samples have been done in laboratory conditions. The ageing time (up to 400 h) influence, at various levels of ageing factors: UV radiation intensity (80—190 W/m2), temperature (35—55 °C) and humidity (30—90%), on the changes of the structures of polymers investigated (shares of carbonyl and olefinic groups from FT-IR spectra — Fig. 1, 2, 4 and 5), on the changes of polymers molecular weights (Fig. 3 and 6, Table 1) and on the changes of mechanical properties during tension (Table 1) has been investigat…