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Potentiometric determination of fluoride in white wines of the Pošip variety : diploma thesis
No full textCilj ovog istraživanja je potenciometrijski odrediti sadržaj fluoridnih iona u bijelim vinima sorte pošip s različitih geografskih područja te usporediti i objasniti moguće razlike u koncentracijama fluorida za različite lokacije i sorte vina. Fluoridi u vinu su određeni metodom standardnog dodatka upotrebom fluorid-ionsko selektivne elektrode. Ispitana je koncentracija fluorida u 12 uzoraka vina sa otoka Pelješca, Korčule, Hvara i iz Konavla. Vinarija s najvećom koncentracijom fluorida (447,4 ± 48,98 µg L -1 ) je smještena na otoku Korčuli, a s najmanjom (264,8 ± 11,47 µg L -1 ) koncentracijom fluorida smještena je u središnjem dijelu otoka Pelješca. Uzrok različitih koncentracija može biti: geografsko područje, upotreba pesticida i umjetnih gnojiva te tehnološki procesi proizvodnje vina. Koncentracije fluorida uzoraka vina iz središnjeg dijela otoka Pelješca su vrlo slične. Uzorci vina proizvedenih u istoj vinariji na Hvaru značajno se razlikuju zbog upotrebe dvije različite sorte vinove loze (pošip vs. pošip selekcija).The aim of this research is to potentiometrically determine the content of fluoride ions in white wines of the Pošip variety from different geographical areas, and to compare and explain possible differences in fluoride concentrations for different locations and wine varieties. Fluorides in wine were determined by the standard addition method using a fluoride-ion selective electrode. The concentration of fluoride in 12 wine samples from the islands of Pelješac, Korčula, Hvar and Konavle was tested. The winery with the highest fluoride concentration (447.4 ± 48.98 µg L -1 ) is located on the Korčula Island, and the winery with the lowest (264.8 ± 11.47 µg L -1 ) fluoride concentration is located in the central part of the Pelješac Island. The cause of different concentrations can be: geographical area, use of pesticides and artificial fertilizers, and technological processes of wine production. Fluoride concentrations of wine samples from the central part of the island of Pelješac are very similar. Samples of wines produced in the same winery on Hvar show significant differences due to the use of two different grape varieties (Pošip vs. Pošip Selection)
Influence of current density and zeolite particle size on the hybrid process of leachate treatment by electrocoagulation in the presence of zeolite : bachelor thesis
No full textIako korozija konstrukcijskih materijala predstavlja negativnu pojavu, kada se elektrokemijski postupci koriste za pročišćavanje otpadnih voda, anodno otapanje metala može imati pozitivan učinak. U ovom radu, ispitan je utjecaj različitih gustoća struje nakon primjene u obradi otpadne vode hibridnim procesom elektrokoagulacije i sintetskog zeolita. Ispitan je i utjecaj različitih veličina čestica zeolita na otapanje elektrode, stanje površine elektrode i efikasnost uklanjanja. Površina elektroda analizirana je snimanjem sa svjetlosnim mikroskopom uz različita uvećanja. Ispitan je utrošak aluminijevih elektroda tijekom hibridnog procesa elektrokoagulacije u prisustvu sintetskog zeolita, te su izvedeni zaključci o stanju površine elektroda nakon odvijanja hibridnog procesa. Bolja efikasnost uklanjanja dobivena je provođenjem eksperimenta pri većim gustoćama struje kao i kod sustava koji su se provodili uz dodatak zeolita veće veličine čestica. Značajno veća oštećenja su na elektrodama koje su se koristile u eksperimentu s dvostruko većom gustoćom struje. Također, značajna oštećenja su zamijećena na elektrodi koja su se koristila u eksperimentu s većim česticama zeolita, što se može povezati s njihovim izraženijim abrazivnim djelovanjem.Although the corrosion of structural materials is a negative phenomenon, when electrochemical processes are used for wastewater treatment, anodic dissolution of metals can have a positive effect. In this work, the influence of different current densities was investigated after they were used in wastewater treatment by a hybrid process of electrocoagulation combined with the addition of synthetic zeolite. Also, the influence of different zeolite particle size on electrode dissolution, electrode surface condition and removal efficiency were tested. The surface of the electrodes was analyzed by recording it with a light microscope at different magnifications. The consumption of aluminum electrodes during the hybrid process of electrocoagulation in the presence of synthetic zeolite was examined, and conclusions were drawn about the condition of the surface of the electrodes after the hybrid process. Better removal efficiency was obtained by conducting the experiment at higher current densities and in systems using larger zeolites particles. The electrodes used in the experiment with double current density were significantly more damaged. Significant damage was also observed on the electrode used in the experiment with larger zeolite particles, which can be associated with the stronger abrasive effect
Thermal and termooxidative degradation of polymer packaging film containing rosemary extract : master thesis
No full textU ovom radu istražen je utjecaj dodatka ekstrakta ružmarina (ER) na toplinsku i termooksidacijsku stabilnost polimerne matrice polietilena (PE) i polipropilena (PP) . Toplinska razgradnja polietilena i polipropilena se odvija kroz jedan stupanj, dok se njihovi kompoziti PE/ER i PP/ER razgrađuju u dva stupnja. Toplinska i termooksidacijska razgradnja ekstrakta ružmarina se odvija kroz tri stupnja. Toplinska postojanost kompozita PE/ER se poboljšava dodatkom ekstrakta, dok u slučaju kompozita PP/ER ekstrakt ne utječe na toplinsku postojanost polimerne matrice polipropilena. U struji kisika čisti polietilen i kompozit PE/ER se razgrađuju u tri područja razgradnje. Termooksidacijska razgradnja čistog polipropilena i kompozita PP/ER se odvija u dva stupnja. Dodatak ekstrakta ružmarina poboljšava termooksidacijsku postojanost obiju istraživanih polimernih matrica, odnosno kompozita, pri čemu je vidljiv značajniji utjecaj na polimernu matricu polietilena.In this work the influence of the addition of rosemary extract (RE) on the thermal and thermooxidative stability of the polymer matrix of polyethylene (PE) and polypropylene (PP) were investigated. Thermal degradation of the polyethylene and polypropylene occurs in a single degradation step while their composites PE/ER and PP/ER decompose in two steps. Thermal and thermooxidative degradation of rosemary extract takes place through three steps. The thermal stability of the PE/ER composite is improved by the addition of the extract, while in the case of the PP/ER composite the extract does not affect the thermal stability of the polypropylene polymer matrix. In the oxygen atmosphere pure polyethylene and PE/ER composite are degraded in three areas of decomposition. Thermooxidative decomposition of pure polypropylene and PP/ER composite takes place in two steps. The addition of rosemary extract improves the thermooxidative stability of both composites, while having a more significant effect on the polyethylene polymer matri
Enzyme inhibition by essential oils of arthemisae species : bachelor thesis
No full textCilj ovog završnog rada bio je pregled dostupne znanstvene literature na temu in vitro inhibicije enzima eteričnim uljima biljaka roda Artemisiae. Brojna bolesna stanja u ljudi tretiraju se ili preveniraju na način da se enzimi ključni u procesima vezanim uz pojedina bolesna stanja inhibiraju. Obzirom da se uz lijekove koji se koriste u tretmanima ovih i sličnih bolesti vezuju i određene nuspojave, znanstvena zajednica je u stalnoj potrazi za tvarima izoliranim iz prirode koji će pomoći u tretmanu pojedinih bolesti. Kao izvori podataka koristile su se dostupne znanstvene baze podataka Web of Science Core Collection i Scopus. Deset biljnih vrsta roda Artemisia testirano je na sposobnost njihovih eteričnih ulja da inhibiraju enzime koji imaju važnu ulogu u tretmanu bolesti u ljudi. To su vrste: A. absinthium, A. alba, A. annua, A. arborescens, A. aucheri, A. campesteris, A. fragrans. A. infranensis, A. macrocephala i A. maderaspatana. Enzimi koji su pri tom ispitivani su AChE, BChE, α-amilaza, α-glukozidaza, tirozinaza, ACE, COX-1 i COX-2. Rezultati su pokazali da eterično ulje izolirano iz nadzemnog dijela biljke A.alba iz Alžira pokazuju najbolju sposobnost inhibicije, osobito enzima AChE i BChE. Dobar inhibicijski učinak ovo eterično ulje pokazuje i na enzim α- amilazu. Eterično ulje iste vrste iz nadzemnih dijelova A.alba iz Maroka pokazuje srednje dobar inhibicijski učinak na enzim α-amilazu i α-glukozidazu. Eterično ulje A.infranensis izolirano iz nadzemnog dijela biljke sabrane u Maroku pokazalo je srednje dobru sposobnost inhibicije α-amilaze i α-glukozidaze. Sva ostala testirana eterična ulja pokazuju lošu sposobnost inhibicije testiranih enzima ili se njihov inhibicijski potencijal ne može procjeniti.The aim of this bachelor thesis was to review available scientific literature on the topic of in vitro enzyme inhibition by essential oils of the genus Artemisiae. Numerous human diseases are treated or prevented by enzyme inhibition. Since certain adverse reactions are associated with medicines used in the treatment of these and similar diseases, the scientific community is constantly searching for substances isolated from nature that would help treat these diseases. Available scientific databases Web of Science Core Collection and Scopus were used as data sources. Ten plant species of the Artemisia genus were tested for the ability of their essential oils to inhibit enzymes that play an important role in treating diseases in humans. These are: A. absinthium, A. alba, A. annua, A. arborescens, A. aucheri, A. campesteris, A. fragrans. A. infranensis, A. macrocephala and A. maderaspatana. The enzymes that are inhibited are AChE, BChE, α-amylase, α-glucosidase, tyrosinase, ACE, COX-1 and COX- 2. The results showed that essential oil isolated from the superground part of Artemisia alba from Algeria shows the best inhibitory capability, especially the enzymes AChE and BChE. Good inhibitory effect of this oil also affects α-amylase enzymes. Essential oil of the same species from the superground parts of the A.alba from Morocco shows a medium inhibitory effect on α-amylase and α-glucosidase enzymes. A. infranensis essential oil isolated from the superground part of Morocco's plant has shown a medium capacity to inhibit α-amylase and α- glucosidase. All other tested essential oils show poor ability to inhibit tested enzymes or their inhibitory potential cannot be estimated
Srtuctural diverity of glucosinolates and their breakdown products in different plant familes : docotral thesis
No full textSAŽETAK Raspodjela glukozinolata unutar biljnih porodica reda Brassicales istražena je UHPLC- DAD-MS/MS analizom desulfoglukozinolata na temelju određenih kvalitativnih i kvantitativnih informacija i to u različitim biljnim tkivima četrdeset osam (48) biljaka iz pet (5) biljnih porodica (Brassicaceae, Capparidaceae, Moringaceae, Resedaceae, Tropaeolaceae) koje rastu u Republici Hrvatskoj i šire. Razvijena je baza MS2 spektara desulfoglukozinolata korištenjem komercijalno dostupnih standarda kao i glukozinolata izoliranih iz prirodnih izvora. Biljna porodica Brassicaceae je sadržavala najraznolikije glukozinolate koje potječu od sedam (7) aminokiselinskih prekursora, i to najčešće od metionina, praćeno s glukozinolatima koji potječu od triptopfana te fenilalanina i/ili tirozina, dok su razgranati alifatski glukozinolati koji potječu od valina, leucina i izoleucina zastupljeni tek u rijetkim vrstama. Jedini poznati glukozinolat, glukokaparin, koji potječe od aminokiseline alanina identificiran je samo u porodici Capparidaceae i to kao glavni u svim istraženim vrstama, dok su ostali glukozinolati u većoj mjeri potjecali od triptofana. Moringa oleifera (porodica Moringaceae) sadržavala je 4-(α-L- ramnopiranoziloksi)benzil-glukozinolat te u manjim količinama tri (3) O-acetilirana izomera istog glukozinolata čiji aminokiselinski prekursor je fenilalanin i/ili tirozin. U vrstama Reseda lutea i R. phyteuma (porodica Resedaceae) identificiran je izomer 4-(α-L-ramnopiranoziloksi)benzil-glukozinolata, 2-(α-L-ramnopiranoziloksi)benzil- glukozinolat karakterističan za biljnu porodicu Resedaceae, koji potječe od fenilalanina, dok je u R. alba kao glavni glukozinolat identificiran 2-hidroksi-2-metilpropil- glukozinolat koji potječe od izoleucina. Tropaeolum majus je sadržavao arilalifatski benzil-glukozinolat kao glavni, praćen sa 3-metoksibenzil-glukozinolatom, a oba potječu od fenilalanina, jedinog poznatog aminokiselinskog prekursora glukozinolata u porodici Tropaeolaceae. Uvidom u kvantitativni sastav glukozinolata odabrane su biljne vrste kao dobri izvori glukozinolata koji su izolirani u obliku desulfoglukozinolata i potvrđeni spektroskopskim tehnikama (MS2, 1 H, 13 C, COSY i HSQC NMR). 3-(Metilsulfinil)propil-glukozinolat je izoliran iz biljke Anastatica hierochuntica (porodica Brassicaceae), 4-hidroksibenzil-glukozinolat iz vrste Sinapis alba (porodica Brassicaceae), metil-glukozinolat iz Capparis orientalis (porodica Capparidaceae), 2-hidroksi-2-metilpropil-glukozinolat iz biljke Reseda alba (porodica Resedaceae) te benzil-glukozinolat iz Tropaeolum majus (porodica Tropaeolaceae). Također, na temelju MS2 spektara i biosintetskih karakteristika identificirana su 4 nova glukozinolata: orto ili meta hidroksi-4-(α-L-ramnopiranoziloksi)benzil-glukozinolat (Moringa oleifera), 4´-O- (β-D-apiofuranoziloksi)benzil-glukozinolat (Hesperis laciniata i Thlaspi perfoliatum), 4- hidroksi-1-metoksiindol-3-ilmetil-glukozinolat (Thlaspi perfoliatum) te 3-hidroksi-(4- metilsulfonil)butil-glukozinolat (Barbarea vulgaris) čije strukture trebaju dodatnu potvrdu NMR-om. Stabilnost desulfo-4-(metilsulfinil)but-3-enil-glukozinolata izoliranog iz biljke Matthiola incana ispitivana je tijekom jednomjesečnog razdoblja te je utvrđena njegova nestabilnost u vodenoj otopini, odnosno drastičan pad sadržaja (do 80 %) praćen spontanom konverzijom u cikličke tioimidatne N-okside. Korištenjem konvencionalnih (enzimska hidroliza i hidrodestilacija) te modernih metoda (mikrovalna destilacija te hidrodifuzija i gravitacija) ispitan je enzimski i termički utjecaj na razgradnju glukozinolata. U uvjetima termičke razgradnje potpomognute mikrovalovima dobiveni su manji prinosi razgradnih produkata u odnosu na termičku razgradnju tijekom hidrodestilacije te enzimsku hidrolizu. Izotiocijanati kao razgradni produkti glukozinolata su se pokazali nestabilnim pri uvjetima GC-MS mjerenja i to za ω-metilsulfinilne C3, C5 i C6 izotiocijanate čiji je raspad rezultirao nastankom odgovarajućih olefinskih izotiocijanata. Dodatno, zbog prisutnosti elektron-donirajuće hidroksilne skupine u para položaju na benzenskom prstenu, kod 4-hidroksibenzil- izotiocijanata i 4-hidroksi-3,5-dimetoksibenzil-izotiocijanata, utvrđena je nestabilnost koja vodi ka nastanku artefakata tijekom GC-MS mjerenja. Također, razgradni produkti indolnih glukozinolata nisu identificirani. Ovime je istaknut nedostatak neizravne metode identifikacije glukozinolata preko razgradnih produkata u biljnim vrstama. U biljci Eruca vesicaria biofortificiranoj selenijem iz natrijevog selenata identificiran je 4-(metilseleno)butil-glukozinolat izveden iz selenometionina na temelju MS2 spektra koji je po prvi puta prikazan. Utvrđeno je da hidroponski uzgojene klice pet (5) odabranih biljaka iz porodice Brassicaceae imaju visoki sadržaj karakterističnih glukozinolata zbog čega predstavljaju dobar izvor za njihovu izolaciju.ABSTRACT Distribution of glucosinolates within plant families of the order Brassicales was investigated using qualitative and quantitative UHPLC-DAD-MS/MS analysis of desulfoglucosinolates in different plant tissues of forty-eight (48) plants from five (5) plant families (Brassicaceae, Capparidaceceae, Moringaceae, Resedaceae, Tropaeolaceae) growing in the Republic of Croatia and worldwide. A database of MS2 spectra of desulfoglucosinolates was developed using commercially available standards as well as glucosinolates isolated from natural sources. The Brassicaceae plant family contained a wide variety of glucosinolates derived from seven (7) different amino acid precursors, most commonly from methionine, followed by glucosinolates derived from tryptophan, phenylalanine and/or tyrosine, while branched aliphatic glucosinolates deriving from valine, leucine and isoleucine were scarce. Glucocapparin, the only known glucosinolate derived from the amino acid alanine, was identified solely in the Capparidaceae family as the main one in all the species studied, while the other glucosinolates largely derived from tryptophan. Moringa oleifera (family Moringaceae) contained 4-(α-L-rhamnopyranosyloxy)benzyl glucosinolate and, in less amount, three O-acetylated isomers of the same glucosinolate derived from phenylalanine and/or tyrosine. In the species Reseda lutea and R. phyteuma (family Resedaceae) an isomer of 4-(α-L-rhamnopyranosyloxy)benzyl glucosinolate, 2- (α-L-rhamnopyranosyloxy)benzyl glucosinolate, was identified characteristic for the plant family Resedaceae, originating from phenylalanine. On the other hand, 2-hydroxy- 2-methylpropyl glucosinolate derived from isoleucine was the major glucosinolate identified in R. alba. The main glucosinolate in Tropaeolum majus was arylaliphatic benzyl glucosinolate followed by 3-methoxybenzyl glucosinolate, both derived from phenylalanine, the only known amino acid precursor of glucosinolates in the Tropaeolaceae family. Insight into the quantitative composition of glucosinolates enabled the selection of the plant species as the sources of glucosinolates for their isolation in the form of desulfoglucosinolates and confirmation by spectroscopic techniques (MS2, 1 H, 13 C, COSY and HSQC NMR). 3-(Methylsulfinyl)propyl glucosinolate was isolated from Anastatica hierochuntica (family Brassicaceae), 4-hydroxybenzyl glucosinolate from Sinapis alba (family Brassicaceae), methyl glucosinolate from Capparis orientalis (family Capparidaceae), 2-hydroxy-2-methylpropyl glucosinolate from Reseda alba (family Resedaceae) and benzyl glucosinolate from Tropaeolum majus (family Tropaeolaceae). Also, based on MS2 spectra and biosynthetic characteristics, four (4) new glucosinolates were identified: ortho or meta hydroxy-4-(α-L- rhamnopyranosyloxy)benzyl glucosinolate (Moringa oleifera), 4´-O-(β-D- apiofuranosyloxy)benzyl glucosinolate (Hesperis laciniata and Thlaspi perfoliatum), 4- hydroxy-1-methoxyindol-3-ylmethyl glucosinolate (Thlaspi perfoliatum) and 3-hydroxy- (4-methylsulfonyl)butyl glucosinolate (Barbarea vulgaris) whose structures need further confirmation by NMR. The stability of desulfo-4-(methylsulfinyl)but-3-enyl glucosinolate isolated from Matthiola incana was studied over a one-month period and its instability in aqueous solution was observed, showing a significant drop in the content (up to 80%) followed by spontaneous conversion to cyclic thioimidate N-oxides. The enzymatic and thermal degradation of glucosinolates was studied by using conventional (enzymatic hydrolysis and hydrodistillation) and modern methods (microwave distillation and hydrodiffusion and gravity). Under microwave-assisted thermal decomposition conditions, lower yields of decomposition products were obtained compared to thermal decomposition during hydrodistillation and enzymatic hydrolysis. Isothiocyanates as degradation products of glucosinolates showed to be unstable at GC-MS conditions for ω-methylsulfinyl C3, C5 and C6 isothiocyanates, which decomposition resulted in the formation of the corresponding olefinic isothiocyanates. Additionally, due to the presence of an electron- donating hydroxyl group in the para position on the benzene ring, in 4-hydroxybenzyl isothiocyanate and 4-hydroxy-3,5-dimethoxybenzyl isothiocyanate, instability lead to formation of artifacts found during GC-MS analysis. Also, degradation products of indole glucosinolates have not been identified. This highlights the disadvantage of an indirect method for the identification of glucosinolates via their degradation products in plant species. In the Eruca vesicaria biofortified by selenium from sodium selenate, 4- (methylseleno)butyl glucosinolate derived from selenomethionine was identified based on the MS2 spectrum shown for the first time. Hydroponically grown sprouts of the five (5) selected plants of Brassicaceae family were found to have a high content of characteristic glucosinolates presenting a good source for their isolation
Determination of funcional compounds in coffee and coffee by-product : bachelor thesis
No full textNusproizvodi kave kao što su pulpa, ljuske i talog kave bogati su bioaktivnim spojevima, uključujući fenole. Na učinkovitost ekstrakcije fenolnih spojeva iz ovih nusproizvoda može se značajno utjecati metodom ekstrakcije i izborom otapala. Trenutna istraživanja usmjerena su na principe zelene ekstrakcije. Cilj ovog rada je bio odrediti fenolni sastav ekstrakata sirove kave, pržene kave i nusproizvoda koji nastaje tijekom njenog prženja pripravljenih dvjema ekstrakcijskim metodama (ekstrakcija potpomognuta ultrazvukom, UZV i ubrzana ekstrakcija otapalima, ASE) uz korištenje različitih otapala (etanol, voda i njihove mješavine). Ukupni fenoli određeni su spektrofotometrijski, dok su pojedine fenolne kiseline detektirane tekućinskom kromatografijom visoke učinkovitosti (HPLC). Rezultati su pokazali značajan sadržaj ukupnih fenola u svim uzorcima kod ASE (520-5910 mg GAE/L) i UZV (343-5020 mg GAE/L) metode. Kod obiju ekstrakcijskih metoda klorogenska kiselina je najdominantnija fenolna kiselina, nakon koje slijedi kava kiselina. Na razlike u rezultatima značajno su utjecali korišteno otapalo i metoda ekstrakcije. U ekstraktima ASE, sadržaj ukupnih fenola se smanjio sa smanjenjem sadržaja vode u smjesi otapala, trend koji nije primijećen u ekstraktima UZV. Ova studija pruža uvid u razvoj učinkovitih procesa ekstrakcije za proizvodnju visokokvalitetnih ekstrakata koji se potencijalno mogu koristiti u prehrambenoj industriji.Coffee by-products such as pulp, husks and coffee grounds are rich in bioactive compounds, including phenols. The efficiency of extraction of phenolic compounds from these by-products can be significantly influenced by the extraction method and the choice of solvent. Current research focuses on the principles of green extraction. The aim of this work was to determine the phenolic composition of green coffee extracts, roasted coffee and by-products produced during its roasting,prepared by two extraction methods (ultrasound-assisted extraction, UAE and accelerated solvent extraction, ASE) using different solvents (ethanol, water and their mixtures). The total phenols were determined spectrophotometrically, while the individual phenolic acids were detected by high performance liquid chromatography (HPLC). The results showed a significant content of total phenols in all samples using the ASE (520-5910 mg GAE/L) and UAE (343-5020 mg GAE/L) methods. In both extraction methods, chlorogenic acid is the dominant phenolic acid, followed by caffeic acid. The differences in the results were significantly influenced by the solvent used and the extraction method. In ASE extracts, the content of total phenols decreased with decreasing water content in the solvent mixture, a trend that was not observed in UAE extracts. This study provides valuable insights into the development of efficient extraction processes for the production of high-quality extracts that can potentially be used in the food industry
Measurements of CO2, CO and NO2 concentrations in the area of the city of Zenica : bachelor thesis
No full textZrak je smjesa plinova čiji sadržaj može ovisiti o različitim faktorima kao što su nadmorska visina, meteorološki uvjeti, izvori onečišćenja itd. Onečišćenje zraka igra značajnu ulogu u današnjem svijetu pri čemu veliki udio proizlazi iz ljudskih aktivnosti. Loša kvaliteta zraka utječe na okoliš, a samim time i na zdravlje ljudi. Mjerenje kvalitete zraka postalo je dijelom raznih zakonskih okvira i uredbi kojim se nastoji kontrolirati emisija onečišćujućih tvari. Ugljikov(IV) oksid (CO 2 ) je staklenički plin čija koncentracija u atmosferi kontinuirano raste još od industrijske revolucije te se njegova koncentracija nastoji kontrolirati. Zakonski su određene granične vrijednosti koncentracije plinova ispod kojih ti plinovi ne predstavljaju opasnost, odnosno to je vrijednost ispod koje postoji najmanji mogući rizik od štetnih učinaka na ljudsko zdravlje i/ili okoliš. U sklopu zakonskih uredbi, jedni od tih plinova su dušikov(IV) oksid (NO 2 ) i ugljikov(II) oksid (CO). Njihovo mjerenje, zajedno s CO 2 , provedeno je na području grada Zenice. Ustanovljeno je da je najveća srednja koncentracija CO 2 izmjerena na mjernoj postaji broj 2, tj. na kružnom toku te je iznosila 606,25 ppm. Najveća srednja vrijednost koncentracije NO 2 također je izmjerena na mjernoj postaji broj 2 i iznosila je 0,0275 ppm. Na postaji broj 3, u naselju Tetovo, izmjerena je najveća srednja vrijednost koncentracije CO u iznosu od 2,5 ppm.Air is a mixture of gases whose composition can depend on various factors such as altitude, weather conditions, pollution sources, etc. Air pollution plays a significant role in today's world, with a large share arising from human activities. Poor air quality affects the environment and, consequently, human health. Measuring air quality has become part of various legal frameworks and regulations aimed at controlling the emission of pollutants. Carbon dioxide (CO₂) is a greenhouse gas whose concentration in the atmosphere has been continuously rising since the Industrial Revolution, and efforts are being made to control its levels. Legally defined limit values for gas concentrations are established below which these gases do not pose a danger; that is, they represent a value below which there is the least possible risk of harmful effects on human health and/or the environment. Among the gases regulated by legal frameworks are nitrogen dioxide (NO₂) and carbon monoxide (CO). Their measurements, along with CO₂, were conducted in the area of the city of Zenica. It was found that the highest average concentration of CO₂ was measured at monitoring station number 2, located at the roundabout, and it amounted to 606.25 ppm. The highest average concentration of NO₂ was also measured at monitoring station number 2, amounting to 0.0275 ppm. At station number 3, in the Tetovo settlement, the highest average concentration of CO was measured at 2.5 ppm
Artemisia absinthium L.: Chemical composition and biological activity : diploma thesis
No full textCilj ovog rada bio je izolirati i odrediti kemijski sastav eteričnih ulja pelina (Artemisia absinthium L.) sakupljenih na različitim lokalitetima te u različitim sezonama, ispitati sposobnost inhibicije eteričnih ulja na djelovanje enzima acetilkolinesteraze, butirilkolinesteraze i α-glukozidaze te istražiti antioksidacijsku aktivnost. Predominantni spojevi eteričnog ulja pelina iz Sinja su cis-sabinil-acetat i cis-epoksi-ocimen, eteričnog ulja pelina iz Mostara su cis-epoksi-ocimen i cis-krizantemil-acetat, eteričnog ulja pelina iz Zaboka su trans-tujon i cis- epoksi-ocimen te ulja pelina iz Obrovca je cis-epoksi-ocimen. Kod svih analiziranih uzoraka ulja ove biljke sabrane na različitim lokacijama i u različitim sezonama branja kao dominantne komponente ulja javljaju se oksidirani monoterpenski spojevi-monoterpenoidi. Eterična ulja biljke A. absinthium L. pokazuju umjerenu ili slabu sposobnost inhibicije enzima AChE i BChE, ne inhibiraju ili umjereno inhibiraju enzim α-glukozidazu, pokazuju slab redukcijski potencijal i ne pokazuju sposobnost hvatanja slobodnih DPPH radikala.The aim of this study was to isolate and determine the chemical composition of essential oils of wormwood (Artemisia absinthium L.) collected at different sites and in different seasons, to examine the ability to inhibit essential oils on the enzymes acetylcholinesterase, butyrylcholinesterase and α-glucosidase and to investigate antioxidant activity. The predominant compounds of wormwood essential oil from Sinj are cis-sabinyl-acetate and cis-epoxy-ocimen, wormwood essential oil from Mostar are cis-epoxy-ocimen and cis-chrysanthemum-acetate, wormwood essential oil from Zabok are trans-thujone and cis-epoxy-ocimen and oils wormwood from Obrovac is cis-epoxy-ocimen. In all analyzed oil samples of this plant collected at different locations and in different harvesting seasons, oxidized monoterpene compounds-monoterpenoids appear as the dominant oil components. The essential oils of A. absinthium L. show moderate or weak ability to inhibit the enzymes AChE and BChE, do not inhibit or moderately inhibit the enzyme α-glucosidase, show weak reduction potential and do not show the ability to capture free DPPH radicals
Structural and thermal characterization of polylactic acid/calcium lactate composited : diploma thesis
No full textModifikacija polilaktidne kiseline (PLA) provedena je dodatkom kalcijevog laktata (CL) s ciljem određivanja njegovog utjecaja na strukturna i toplinska svojstva te kristalnost PLA. Uspješno su određeni optimalni uvjeti za predmješanje početnih materijala kao i uvjeti ekstrudiranja na dvopužnom ekstruderu s kontrarotirajućim vijcima. Primjenom infracrvene spektroskopije s Fourierovom transformacijom (FTIR) utvrđeno je nepostojanje interakcija između PLA i CL. Diferencijalna pretražna kalorimetrija (DSC) je primijenjena u svrhu istraživanja utjecaja CL na toplinska svojstva i kristalnost PLA. Utvrđeno je nukleacijsko djelovanje CL pri čemu su toplinske značajke PLA ostale nepromijenjene neovisno o sastavu. Primjenom neizotermne termogravimterije (TG) istraživan je utjecaj CL na toplinsku postojanost PLA pri čemu je utvrđeno znatno narušavanje toplinske postojanosti PLA i s najmanjim udjelom CL (2 mas.%). S primijenjenim metodama analize nije utvrđen optimalan udio CL koji bi omogućio raspodjelu kalcijevih iona po masi bez narušavanja strukture i toplinskih svojstava PLAThe modification of polylactic acid (PLA) was carried out by adding calcium lactate (CL) with the aim of determining its influence on the structural and thermal properties, as well as crystallinity of PLA. Optimal conditions for premixing the initial materials as well as the extrusion conditions on a twin-screw extruder with counter-rotating screws were successfully identified. Fourier transform infrared spectroscopy (FTIR) revealed no interactions between PLA and CL. Differential scanning calorimetry (DSC) was applied to investigate the influence of CL on the thermal properties and crystallinity of PLA. The nucleating effect of CL was observed, while the thermal properties of PLA remained unchanged regardless of the composition. Non-isothermal thermogravimetry (TG) was used to study the influence of CL on the thermal stability of PLA. Significant degradation of the thermal stability of PLA was determined, even with the smallest addition of CL (2 wt.%). By applying analysis methods, the optimal CL content was not established. By applying analysis methods, the optimal CL content that would allow the distribution of calcium ions by mass without disrupting the structural and thermal properties of PLA, was not established
Thermal and thermooxidative degradation of PVAL/PEO blends prepared by solution casting method : master thesis
No full textU ovom radu provedena je toplinska i termooksidacijska razgradnja filmova PVAL, PEO i mješavina PVAL/PEO. Toplinska razgradnja PVAL-a odvija se kroz tri stupnja, a PEO-a kroz jedan stupanj pri čemu je PEO toplinski stabilniji. Sve mješavine pokazuju tri razgradna stupnja. Mješavine sastava 70/30 i 30/70 pokazuju bolja toplinska svojstva od čistih komponenti, dok mješavina 50/50 ima najlošiju toplinsku postojanost. U struji kisika, odnosno pri termooksidacijskoj razgradnji PEO zadržava jedan stupanj razgradnje dok se PVAL razgrađuje kroz četiri stupnja razgradnje. Bolju termooksidacijsku stabilnost pokazuje PVAL. Mješavine sastava 50/50 i 30/70 se razgrađuju kroz četiri stupnja, a mješavina 70/30 kroz pet stupnjeva. Mješavina sastava 50/50, kao i pri toplinskoj razgradnji, pokazuje najlošiju termooksidacijsku stabilnost.In this paper thermal and thermooxidative degradation of PVAL, PEO and PVA/PEO blends films was investigated. Thermal degradation of PVAL takes place through three stages while the thermal degradation of PEO occurs in a single stage, however PEO is more stable. All PVAL/PEO blends show three degradation stages. The 70/30 and 30/70 PVAL/PEO blends show enhanced thermal properties in comparison to the pure components, while the 50/50 blend has the worst thermal stability. Thermooxidative degradation of PVAL occurs trough four stages, while PEO keep single step degradation. Better thermooxidation stability has PVAL. The 50/50 and 30/70 blends are degraded through four stages, and 70/30 blend through five degradation stages. The 50/50 PVAL/PEO blend, as well as during the thermal degradation, shows the worst thermooxidation stability