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107. Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type AnalysisMaryline Pflieger, Petra Makorič, Manca Kovač Viršek, Špela Koren, 2017, pregledni znanstveni članek Opis: Plastic resin pellets, categorized as microplastics (≤5 mm in diameter), are small granules that can be unintentionally released to the
environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and
on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might
consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the
hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid
determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets,
analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets
by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy.
The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main
metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes
a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.
Ključne besede: Environmental Sciences, Issue 125, Microplastics, resin pellets, pesticides, persistent organic pollutants, organochlorine pesticides, dichlorodiphenyltrichloroethane, endosulfan, hexachlorocyclohexane, lindane, Fourier transform infrared spectroscopy, pressurized fluid extractor
Objavljeno v RUNG: 10.07.2017; Ogledov: 4659; Prenosov: 0 |
108. Analysis of polychlorinated biphenyls adsorbed on plastic pellets: Comparison of extraction techniquesPetra Makorič, 2017, magistrsko delo Opis: Plastic resin pellets are one of the main components of plastic fragments in the marine environment. They are small granules, generally cylinder or disk-shaped, with a diameter of a few millimetres used as industrial raw material for the production of plastic manufactured items. Resin pellets can be unintentionally released to the environment during manufacturing and transport, and can reach the ocean through processes such as surface run-off. Because of their environmental persistence, they are widely distributed in the oceans and on the beaches, all over the globe. Plastic pellets are also a sink of toxic compounds such as polychlorinated biphenyls (PCBs) that are present in the environment.
During this thesis, we designed a protocol for extracting and analysing PCBs from marine plastic resin pellets. Although pressurized fluid extraction (PFE) is not commonly used in the field of microplastics, it is a reliable and efficient technique applied in other research areas. Thus, this method was tested in this work. PCBs were extracted from plastic pellets with PFE at 65 ºC and under 100 bar with hexane. Then, the extracts were concentrated to 1 mL, cleaned up on Florisil cartridge through solid-phase extraction. Prior to analysis on GC-ECD, the cleaned extracts were concentrated again.
In the second part of the thesis, the following four extraction techniques of PCBs from plastic resin pellets were compared: Soxhlet extraction, PFE, ultrasonication and maceration. The obtain results have shown that the best efficiency and repeatability of extraction is achieved with PFE. In case of Soxhlet extraction, the results were unrepeatable. Maceration and ultrasonication had 40-45 % lower extraction efficiencies than PFE.
Ključne besede: PCB, plastic resin pellets, pressurized fluid extraction, Soxhlet, maceration, ultrasonication, microplastics
Objavljeno v RUNG: 22.06.2017; Ogledov: 5249; Prenosov: 268
 Celotno besedilo (1,95 MB) |
109. Teorija jezika skozi prizmo usvajanja nejezikovnih prvin – pilotna študijaTjaša Popović, 2017, diplomsko delo Opis: V središču diplomske naloge je možnost, da bi lahko temelje za univerzalno hierarhijo funkcijskih projekcij, ki jo opazujemo v jeziku, iskali v splošni kogniciji (Žaucer 2015). Če taki temelji obstajajo, lahko pričakujemo, da obstaja tudi povezava med vrstnim redom funkcijskih projekcij, v katerih se v samostalniški zvezi pojavljajo pridevniki, in vrstnim redom usvajanja konceptov, ki jih pridevniki v ustrezni funkcijski projekciji izražajo. Na podlagi preteklih raziskav (Radford 1996) pričakujemo, da bodo otroci koncepte, ki so v hierarhiji postavljeni nižje, usvojili prej in tiste, ki so višje, kasneje. V diplomskem delu so zato predstavljene kartografske raziskave, ki kažejo, da obstaja v samostalniški zvezi univerzalna hierarhija pridevnikov. Sledeč Scottu (2002)preverjamo, ali slovenščina potrjuje univerzalno hierarhijo, ki je bila predlagana predvsem na podlagi angleščine. Pri tem je posebna pozornost posvečena pridevnikom, ki poimenujejo velikost, obliko in barvo. Sklenemo, potrjujoč Scottove (2002) trditve, da si ti sledijo v zaporedju velikost → oblika → barva. V nadaljevanju so predstavljeni rezultati pilotne študije, s pomočjo katere smo pri otrocih preverjali razumevanje konceptov velikosti, oblike in barve. Na podlagi dobljenih rezultatov ne moremo sklepati o vrstnem redu usvajanja konceptov velikosti, oblike in barve, saj se je pokazalo, da so otroci, ki so nalogo razumeli, že usvojili vse tri raziskovane koncepte.
Ključne besede: Univerzalna hierarhija funkcijskih projekcij, pridevniki, samostalniška zveza, usvajanje jezika, koncepti, velikost, oblika, barva.
Objavljeno v RUNG: 25.05.2017; Ogledov: 6181; Prenosov: 283
Celotno besedilo (1,02 MB) |
110. O koordiniranih in večkratnih k-vprašanjih v slovenščiniPetra Mišmaš, 2017, izvirni znanstveni članek Opis: Prispevek obravnava večkratna in koordinirana k-vprašanja v slovenščini, pri čemer je pozornost posvečena zlasti primerjavi med obema skupinama vprašanj, k problematiki pa pristopamo v teoretičnem okviru tvorbene slovnice. Na podlagi razlik med koordiniranimi in večkratnimi k-vprašanji sklenemo, da zahtevata obe skupini vprašanj kljub navideznim podobnostim ločeno obravnavo tudi v slovenščini. Ta sklep je izhodišče za nadaljnje raziskave koordiniranih k-vprašanj v slovenščini, saj so tovrstna vprašanja v slovenskem jezikoslovju do tega trenutka v veliki meri neraziskana.
Ključne besede: slovenščina, tvorbena slovnica, skladnja, koordinirana k-vprašanja, večkratna k-vprašanja
Objavljeno v RUNG: 03.04.2017; Ogledov: 4450; Prenosov: 0
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