A geochemical and mineralogical study was performed on lignite samples from the Upper Miocene Kovin deposit, hosting three coal seams. The Kovin lignite is characterized by high moisture content, ...medium to high ash yield, medium to high sulphur content and a relatively low gross and net calorific value. The mineralogical composition, and major and trace element contents were determined by X-ray diffraction, scanning electron microscopy with energy dispersive Xray spectroscopy (SEM-EDS) analyses, and inductively coupled plasma optical emission spectrometry (ICP-OES). The most abundant minerals in all lignite samples from the three coal seams are clays (illite/smectite), silicates (quartz, plagioclase), sulphates (gypsum/anhydrite) and carbonate (calcite). The other iron-rich minerals are sulphides, oxides and hydroxides (pyrite, magnetite, haematite, and limonite). In general, mineral matter in the matrix coal consists of illite/ smectite and quartz, while xylite-rich coals, apart from illite/smectite, have a higher content of sulphates and Fe-oxide/hydroxide minerals. The lignite from the Kovin deposit is enriched in As, Cd, Co, Cr, Cu, Ga, Li, Mn, Mo, Ni, Pb, V, Zn, Gd, Tb, Er and Lu in comparison with the Clarke values for brown coals. The statistical analysis of bulk compositional data shows inorganic affinity for the majority of the major and trace elements and possible association with pyrite, illite/ smectite and calcite.
Tokom rada na disertaciji ispitivana su 33 uzorka mogućih matičnih stena iz tri najznačajnije lokalne generativne depresije našeg dela Panonskog basena: Banatsko Aranđelovo, Srpska Crnja i Zrenjanin. ...Devet ispitivanih uzoraka je bilo iz srednjeg miocena (baden i sarmat), 16 uzoraka je iz gornjeg miocena (panon i pont), sedam uzoraka iz nedefinisanog miocena (srednji miocen ili panon) i jedan uzorak je nepoznate stratigrafske pripadnosti. Uzorci potiču sa relativnih dubina od 1540 do 3420 m, na kojima temperature iznose 88-175 °C. Ispitivano područje se odlikuje specifičnim geotermičkim karakteristikama: povišenim geotermalnim gradijentom (4,0 – 7,5 °C/100m), toplotnim tokovima visokog intenziteta (90 – 110 mW/m2) i veoma velikim brzinama zagrevanja sedimenata srednjeg i gornjeg miocena (9 – 22 °C/milion godina).Osnovni predmet disertacije bio je definisanje zone generisanja nafte u Panonskom basenu Srbije, odnosno definisanje „naftnog prozora” na osnovu detaljnih geohemijskih istraživanja u kombinaciji sa već poznatim geološkim podacima. Ciljevi ove teze bili su i utvrđivanje porekla, sredine taloženja i zrelosti organske supstance ispitivanih matičnih stena, kao i utvrđivanje primenljivosti maturacionih parametara i jednačina za izračunavanje refleksije vitrinita za uzorke matičnih stena iz hipertermalnog basena. Na osnovu korelacije biomarkerskih parametara procenjena je i starost za sedam uzoraka iz nedefinisanog miocena.Opšta karakterizacija organske supstance podrazumevala je elementarnu analizu i Rock-Eval pirolizu, a refleksija vitrinita je korišćena za utvrđivanje Izvod ii stepena zrelosti kerogena. Rastvorna organska supstanca je izolovana ekstrakcijom po Soksletu (Soxhlet), a zatim je razdvojena na ugljovodonični deo i polarni ostatak. Za analizu individualnih biomarkera (n-alkani, izoprenoidni alifatični alkani, sterani i terpani) i aromatičnih jedinjenja (derivati naftalena, fenantrena i dibenzotiofena) primenjene su savremene instrumentalne metode gasna hromatografija sa masenom spektrometrijom (GC-MS) i gasna hromatografija sa tandemskom masenom spektrometrijom (GC-MS-MS).Organska supstanca je mešovitog drvenasto-algalnog porekla, pretežno sačinjena od kerogena tipa II. Taloženje organske supstance se odvijalo u promenljivim uslovima, od redukcionih do suboksičnih, pri čemu se salinitet paleosredine postepeno smanjivao od srednjeg ka gornjem miocenu.Početak generisanja nafte odgovara temperaturi 110-120 °C i dubini od 1850 do 2100 m, pri refleksiji vitrinita, Rc ≈ 0,53-0,58 %. „Naftni prozor“ dostiže maksimum na oko 145-150 °C, pri Rc ≈ 0,72-0,75 %, na dubinama od 2600 do 2900 m. Kraj „naftnog prozora“ je na 170-175 °C, pri Rc ≈ 0,89-0,93 %, i dubini od oko 3500 m. Izvedena je i aproksimativna kalibracija vrednosti biomarkerskih maturacionih parametara u odnosu na „naftni prozor“. Pri tome je definisana i moguća primena dva, u organsko-geohemijskoj literaturi, relativno nova biomarkera, „rano eluirajućih“ hopana (čija struktura je pretpostavljena, ali ne i u potpunosti potvrđena) i C(14a)-homo-nor-17α(H)- hopana.Kada je reč o primenljivosti maturacionih parametara i jednačina za izračunavanje refleksije vitrinita na uzorcima matičnih stena iz hipertermalnog basena ustanovljeno je da su najprimenljivije jednačine zasnovane na savremenoj temperaturi, steranskim i dibenzotiofenskim maturacionim parametrima i maturacionom parametru predloženom u ovoj disertaciji koji predstavlja odnos C(14a)-homo-nor-17α(H)-hopana i C30 17α(H),21β(H)-hopana. Takođe, po prvi put su ustanovljene linearna i logaritamska jednačina koje povezuju refleksiju vitrinita sa vrednostima steranskog maturacionog parametra C29ββ(R)/C29(ββ(R)+αα(R)).
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•Co2+ doped Al2O3 coatings were formed by plasma electrolytic oxidation (PEO).•Cobalt content of coatings increased in agreement with Co2+ content of PEO solutions.•Cobalt in coatings ...significantly improved catalytic activity in the Oxone® based AOP.•The Co2+ doped Al2O3 coatings exhibited good stability in the investigated reaction.
The aim of this work is to examine the possibility of the formation of cobalt doped Al2O3 coatings on aluminum substrate by plasma electrolytic oxidation process (PEO) and application of the obtained material as catalyst in the sulfate radical (SO4−) based advanced oxidation process (SR-AOP). The morphology and elemental composition, of the coatings were characterized using Scanning Electron Microscopy. The obtained material was tested as catalyst in SR-AOP in the degradation of model dye (tartrazine) in aqueous solution. Potassium peroxymonosulfate (Oxone®) was used as the source of radicals. The catalytic role of cobalt in tartrazine decolorization was tested in the catalytic system consisting of PEO cobalt doped Al2O3 coated Al plates and Oxone®. It was found that the addition of cobalt precursor into PEO electrolyte solution significantly improved the catalytic properties of obtained coatings with respect to cobalt-free Al2O3 coating and Oxone®. The influence of cobalt content in the supporting electrolyte during PEO process on the catalytic activity of the coatings, as well as Oxone® dosages in SR-AOP, were examined.
Translations of instruments for measuring quality of life developed in certain, mostly more developed, parts of the world usually do not cover regionally specific aspects of health-related quality of ...life, even after transcultural validation. The aim of this study was to develop and validate a reliable questionnaire in Serbian, Croatian, Bosnian, and Montenegrin languages suitable for measuring health-related quality of life in adults.
The study was of a cross-sectional type, assessing the reliability and validity of a newly developed questionnaire for measuring health-related quality of life (HRQoL) in adults residing in western Balkan states (WB-HRQoL). It was conducted on a sample of 489 adults from Serbia, Croatia, Bosnia & Herzegovina, and Montenegro, with a mean age of 52.2±14.4 years and a male/female ratio of 195/294 (39.9%/60.1%).
The definitive version of the WB-HRQoL scale with 19 items showed very good reliability, with Cronbach's alpha 0.905. The scale was temporally stable, and satisfactory results were obtained for divergent and convergent validity tests. Exploratory factorial analysis brought to the surface four domains of health-related quality of life, namely the physical, psychical, social, and environmental.
The WB-HRQoL scale is a reliable and valid generic instrument for measuring HRQoL that takes into account the cultural specifics of the western Balkan region.
Background/Aim. Phthalates are recognized as endocrine-disrupting compounds and are extensively present in a variety of everyday products. Chronic exposure to phthalates is suspected to be associated ...with a range of health disorders. The aim of the study was to examine the abundance of phthalate metabolites in the urine samples among adults in the Autonomous Province of Vojvodina, Serbia, and to determine the prevalence of phthalate metabolites in healthy individuals and those with metabolic disorders such as obesity and newly diagnosed type 2 diabetes mellitus (T2DM). Methods. For the study purpose, the first morning urine sample of 308 participants was screened for the presence of 10 phthalate metabolites: mono-ethyl phthalate (MEP), mono-(2-ethylhexyl) phthalate (MEHP), mono-n-butyl phthalate (MBP), mono-iso-allyl phthalate (MiAP), mono-n-allyl phthalate (MnAP), mono-cyclohexyl phthalate (MCHP), mono-benzyl phthalate (MBzP), mono-n-octyl phthalate (MOP), mono-n-propyl phthalate (MPP) and mono-methyl phthalate (MMP). Results. At least one phthalate metabolite was detected in the first morning urine sample in 50.32% of the examined population. The most frequently detected phthalate metabolites were MEP and MEHP. Out of all phthalate-positive participants, 38.3% of them had one, 10.7% had two, while 1.3% of participants had three phthalate metabolites in the first morning urine sample. A significant difference (p < 0.05) between groups was observed on MEP and MMP frequency, while border-line significant difference (p < 0.1) between groups was observed on MEHP and MCHP frequency. Conclusion. In the Vojvodina region, both healthy adults and those with metabolic disorders such as obesity and newly diagnosed T2DM are predominantly exposed to di-ethyl phthalate and di-(2-ethylhexyl)phthalate since MEP and MEHP were the most frequently detected phthalate metabolites. Further re-search is required in order to provide more details of the phthalates influence on the adverse health effects.
We present here the improved design and development of optical sensor for non-invasive measurements of arterial blood flow waveform. The sensor is based on a physical principle of reflective ...photoplethysmography (PPG). As the light source we used serially connected infrared diodes whereas NPN silicon phototransistors were used as light detectors. The electronic components were molded into square package and poured with silicone. Such preparation produced an elastic superficies that allowed excellent attachment of the sensor on the skin’s surface. Moreover, a serial connection of infrared diodes and phototransistors completely eliminated signal artifacts caused by minor muscle contractions. The sensor recording performances were examined at the photoplethysmographic sites on three different arteries; the commune carotid, femoral and radial and, on each site the sensor demonstrated remarkable capability to make a consistent, reproducible measurements. Because of the advantageous physical and electrical properties, the new sensor is suitable for various cardiovascular diagnostics procedures, especially when long-term measurements of arterial blood flow waveform are required, for monitoring of different parameters in cardiovascular units and for research.
We present here the improved design and development of optical sensor for non-invasive measurements of arterial blood flow waveform. The sensor is based on a physical principle of reflective ...photoplethysmography (PPG). As the light source we used serially connected infrared diodes whereas NPN silicon phototransistors were used as light detectors. The electronic components were molded into square package and poured with silicone. Such preparation produced an elastic superficies that allowed excellent attachment of the sensor on the skin's surface. Moreover, a serial connection of infrared diodes and phototransistors completely eliminated signal artifacts caused by minor muscle contractions. The sensor recording performances were examined at the photoplethysmographic sites on three different arteries; the commune carotid, femoral and radial and, on each site the sensor demonstrated remarkable capability to make a consistent, reproducible measurements. Because of the advantageous physical and electrical properties, the new sensor is suitable for various cardiovascular diagnostics procedures, especially when long-term measurements of arterial blood flow waveform are required, for monitoring of different parameters in cardiovascular units and for research.
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