Repository of the Faculty of Chemistry and Technology, University of Split
Not a member yet
1086 research outputs found
Sort by
Ionic liquids : bachelor thesis
No full textIonske tekućine su soli koje mogu biti u tekućem agregatnom stanju pri sobnoj temperaturi. Najčešće su sastavljene od organskog kationa te anorganskog ili organskog aniona. Razvoj istraživanja ionskih tekućina značajan je zbog njihove široke primjene u raznim tehnologijama i industrijama. Cilj ovog rada je objasniti što su ionske tekućine, njihovu strukturu, razna fizikalno-kemijska svojstva koja posjeduju te njihovu sintezu. Nadalje, cilj ovog rada je opisati primjenu ionskih tekućina u industriji.Ionic liquids are salts that can be in a liquid state at room temperature. They are usually composed of an organic cation and an inorganic or organic anion. The development of research on ionic liquids is significat due to their wide application in vatious technologies and industries. The aim of this paper is to explain what ionic liquids are, their strucutre, various physiochemical properties they possess and their synthesis. Furthermore, the aim of this paper is to describe the application of ionic liquids in industry
Testing of the membrane response made of FePO4 : Ag2S : PTFE = 1 : 2 : 3 and FePO4 : Ag2S : PTFE = 1 : 3 : 4 at pH = 1,5 : bachelor thesis
No full textOsnovni cilj ovog završnog rada je ispitivanje membranskih ion-selektivnih elektroda čiji je glavni sastojak FePO 4 u kiselom mediju (pH=1,5). U radu je opisana priprava i dobivanje membrana te njihovo ispitivanje u otopinama željezovog(III) nitrata i željezovog(III) klorida za odziv na željezove(III) katione. Odziv na željezove(III) ione ispituje se kod sljedećih membrana: • Membrana 2, M2: FePO 4 : Ag 2 S: PTFE u omjeru 1: 1: 2 • Membrana 3, M3: FePO 4 : Ag 2 S: PTFE u omjeru 1: 2: 3 Razvijene membranske elektrode pokazuju zadovoljavajući odziv na željezove(III) ione.The base goal of this bachelor thesis is testing ion-selective membrane electrodes whose ingredient is FePO 4 in acidic medium (pH=1,5). This thesis explains the preparation and production of membranes and their testing in solutions of ferric nitrate and ferric chloride for response to ferric cations. The response to iron(III) ions is tested for the following membranes: • Membrane 2, M2: FePO 4 : Ag 2 S: PTFE in 1: 1: 2 ratio • Membrane 3, M3: FePO 4 : Ag 2 S: PTFE in 1: 2: 3 ratio The membrane electrodes developed show a satisfactory response to the iron(III) ions
Cancer cells metabolism : bachelor thesis
No full textRak se povijesno smatrao kao poremećaj širenja malignih stanica, međutim novija istraživanja i dokazi sugeriraju da ga treba smatrati metaboličkom bolešću. Rastući tumori preusmjeravaju svoje metaboličke programe kako bi zadovoljili i čak premašili bioenergetske i biosintetske potrebe neprekidnog rasta stanica. Invazija tumorskih stanica u okolna tkiva i njihovo širenje (metastaze) na udaljene organe glavni je uzrok smrtnosti većine bolesnika s karcinomom. Metabolički profil koji se može opaziti u stanicama karcinoma uključuje povećanu glikolizu, povećanu potrošnju glukoze i glutamina, pojačano lučenje laktata te poremećaj rada metaboličkih enzima. Stanice raka ne zahtijevaju potrošnju kisika u svrhu dobivanja energije kao što je to slučaj kod normalnih stanica. Umjesto toga, stanice raka se koriste glukozom 5-10 puta više u odnosu na normalnu stanicu za primarnu proizvodnju energije. Bez jasnog razumijevanja načina na koji nastaje rak, postaje teško formulirati uspješnu strategiju za učinkovito dugoročno upravljanje i prevenciju bolesti. Neuspjeh u jasnom definiranju podrijetla raka u velikoj je mjeri odgovoran za neuspjeh značajnog smanjenja stope smrtnosti. Metabolizam karcinoma dobiva sve veću pažnju te je veoma zanimljiv znanstvenicima u istraživanjima protutumorskih terapeutika. Ovim radom dan je kratki prikaz razlika u metabolizmu stanica raka u odnosu na normalnu stanicu te način na koji bi se u budućnosti mogla ciljati meta tumorskog metabolizma kako bi se razvila moguća prikladna protutumorska terapija.Cancer has historically been considered spreading disorder , however recent research and evidence suggest that it should be considered a metabolic disease. Growing toumors redirect their metabolic programs , to meet and even exceed the bioenergetic and biosynthetic needs of continuos cell growth. Invasion of tumor cells intos surrounding tissue and their spread ( metastasis ) to distant organs is a major cause of mortality in most cancer patients. The metabolic profile that can be observed in cancer cells includes increased glycolysis , increased consumption of glucose and glutamine , increased lactate secreation , and impaired use of metabolic enzyme metabolism . Cancer cells do not required oxygen , consumption for purpose of obtaining energy as is the case with normal cells . Instead cancer cells use glucose 5-10 times more than a normal cell for primary energy production. Without a clear understanding of how cancer develops , it becomes difficult to formualte a successful strategy for effective long – term managemnt and prevention. Failure to clearly define the origine of cancer is largely resposible for the failure to significantly reduce the death rate from the disease. Cancer metabolism is gaining increasing attention and is of great interest to scientists in research for antitumor therapy. This paper provides a breef overview of the differences in cancer in cell metabolism realtive to normal cells and way in which the target of tumor metabolism could be targeted in the future in order to develope a possible appropriate antitumor therapy
The influence of the molecular weight of poly(ethylene oxide) on the properties of PEO/chloro f, hib-POSS nanocomposites : bachelor thesis
No full textU ovome radu pripravljeno je osam različitih uzoraka od kojih prva četiri predstavljaju čisti PEO različitih molekulskih masa (100 000, 300 000, 1·10 6 i 5·10 6 ) a druga četiri predstavljaju kompozite kojima je dodano 5% nanočestica kloro fenil hepta izobutil poliedarskog oligomernog silseskvioksana (PEO/kloro f,hib-POSS). Uzorci su pripremljeni metodom taljenja u statičkim uvjetima te analizirani metodom diferencijalne pretražne kalorimetrije i infracrvene spektroskopije s Fourierovom transformacijom. Cilj ovog rada bio je odrediti toplinske karakteristike PEO/POSS nanokompozita, istražiti interakcije PEO-a i POSS-a te zaključiti o mogućnosti modifikacije svojstava PEO-a dodatkom kloro f,hib-POSS u cilju smanjivanja kristalne faze PEO-a. Nađeno je da je PEO djelomično kristalni polimer koji pokazuje staklasti prijelaz u temperaturnom području od -60 do -50 °C i talište u temperaturnom području od 55-95 °C. Najveći udio kristalne faze ima PEO molekulske mase 100 000 i iznosi 70 %, dok ostali PEO-i molekulske mase 300 000, 1·10 6 i 5·10 6 imaju od 60 – 65 % kristalne faze. Navedenim metodama istraživanja nisu potvrđene interakcije polimera i nanočestica. Izostanak interakcija PEO-a i kloro f,hib POSS nanočestica najvjerojatnije je posljedica loše dispergiranosti nanočestica u polimernoj matrici. Naime, kod priprave nanokompozita metodom taljenja u statičkim uvjetima može doći do aglomeracije nanočestica te se dobije obični kompozit, a ne nanokompozit.In this thesis, eight different samples were prepared, the first four represent pure PEO of different molecular weights (100 000, 300 000, 1·10 6 , 5·10 6 ) and the other four represent composites to which 5% nanoparticles of chloro phenyl hepta isobutyl polyhedral oligomeric silsesquioxane (PEO/chloro f,hib-POSS) were added. Samples were prepared by the melting method in the static conditions and analyzed by differential scanning calorimetry and FT-IR spectroscopy. The aim of this study was to determine the thermal characteristics of PEO/POSS nanocomposites, to investigate the interactions of PEO and POSS and to conclude about the possibilities of modifying the properties of PEO by adding chloro f,hib-POSS in order to reduce the crystal phase of PEO. PEO was found to be a partially crystalline polymer showing glass transition in the temperature range of -60 °C to -50 °C and a melting in the temperature range of 55-95 °C. The largest crystalline phase has a PEO of molecular mass of 100 000 and it is 70% while other PEOs have from 60 to 65% of the crystalline phase. The applied methods did not confirm the interactions between polymers and nanoparticles. The absence of interactions of PEO and chloro f,hib-POSS nanoparticles is most likely due to poor dispersion of nanoparticles in the polymer matrix. During the preparation of nanocomposites by the melting method in static conditions, agglomeration of nanoparticles can occur and the result is regular composite, not a nanocomposite
Multi-stage leachate treatment from municipal waste landfill Bikarac using chemical precipitation, aeration and fenton-like process : diploma thesis
No full textU ovome radu provedena je fizikalno-kemijska karakterizacija procjedne vode s odlagališta otpada Bikarac te njena obrada primjenom kemijskog taloženja, aeracije i Fenton sličnog procesa. Rezultati su pokazali da primjenom kemijskog taloženja i aeracije vrijednosti pokazatelja BPK 5 , KPK, N po Kjeldahlu i NH 3 -N su ispod MDK vrijednosti propisanih Pravilnikom te se obrađena procjedna voda može ispustiti u sustav javne odvodnje nakon neutralizacije, ali ne i u površinske vode. Ispitan je utjecaj pH, koncentracije Fe 3+ i H 2 O 2 , molarnog koncentracijskog omjera Fe 3+ :H 2 O 2 te vremena kontakta na smanjenje KPK vrijednosti primjenom Fenton sličnog procesa. Najučinkovitije smanjenje KPK primjenom Fenton sličnog procesa u iznosu od 40% postignuto je pri optimalnim uvjetima procesa: pH=4, molarnom koncentracijskom omjeru Fe 3+ :H 2 O 2 =1:30 te koncentraciji Fe 3+ od 18 mg/L. Na temelju kinetičkih rezultata ustanovljeno je da je stvarni red reakcije između prvog i drugog reda. Primjenom Fenton sličnog procesa nisu se postigli uvjeti za ispust obrađene procjedne vode u površinske vode.In this paper, the physico-chemical characterization of leachate from the Bikarac landfill and its treatment using chemical precipitation, aeration and Fenton-like process was performed. The results showed that by applying chemical precipitation and aeration the values of BOD 5 , COD, Kjeldahl nitrogen and ammonia are below the permissible limits prescribed by the Croatian legislative and treated leachate can be discharged into the public system after neutralization, but not into the surface waters. The influence of pH, concentration of Fe 3+ and H 2 O 2 , molar concentration ratio of Fe 3+ :H 2 O 2 and contact time on the decreasing of COD values using the Fenton-like process was also investigated. The most effective decreasing of COD using Fenton-like process in the amount of 40% was achieved under optimal process conditions: the pH=4, the molar concentration ratio Fe 3+ :H 2 O 2 =1:30, as well as Fe 3+ concentration of 18 mg/L. Based on the kinetic results, it was found that the real reaction order was between the first and second order. By applying the Fenton-like process, the conditions for the discharge of treated leachate into surface waters were not achieved
Determination of PID controller parameters for temperature control in batch reactor based on simulated step test data : diploma thesis
No full textCilj ovog rada bio je analizirati različite metode ugađanja PID regulatora na temelju podataka simuliranog testa na skok za proces vođenja temperature u šaržnom reaktoru. Za procese u kojima je vođena veličina temperatura, potrebno je s velikom pozornošću pratiti odziv procesa i rezultate ugađanja regulatora. Takvi procesi najčešće zahtijevaju da temperatura dolazi u radnu točku brzo i bez ikakvih prebačaja i oscilacija. Povećanje temperature ubrzava kemijsku reakciju što, u konačnici, može negativno utjecati na kvalitetu proizvoda. Odabiru najpogodnije metode ugađanja PID regulatora, ne može se pristupiti bez prikupljenog znanja o procesu. Karakterizacija procesa se provela korištenjem programskih paketa Simcet 9.2. (u kojem je proveden test na skok) i Pitops 7 (u kojem su određeni parametri modela). Ugađanje regulatora je provedeno u modulu Pitops-PID pri čemu su primijenjene klasična Ziegler-Nichols metoda te Pitops metode. Rezultati su pokazali da se najstabilniji i najbrži odziv uz minimalan prebačaj dobije kod Pitops ITAE metode.The aim of this paper was to analyze different tuning methods of PID controllers based on simulated step test data for the process of temperature control in a batch reactor. For processes in which the temperature is the controlled variable, it is necessary to closely monitor the process response and the results of controller tuning. Such processes usually require for the temperature to reach the setpoint quickly and without overshoots and oscillations. Increasing the temperature accelerates the chemical reaction which, ultimately, can negatively affect the quality of the product. Prior to selection of PID tuning method, process should be characterized. Process characterization was accomplished using Simcet 9.2 (in which step test was performed) and Pitops 7 (in which the model parameters were determined) software packages. PID controller tuning was performed in the Pitops-PID module using the classical Ziegler-Nichols method and the Pitops methods. The results showed that the most stable and fastest response with minimal overshoot was obtained with the Pitops ITAE method
Analytic methdos of heavy metals determination in plant materials : bachelor thesis
No full textU prirodi su prisutne veće koncentracije teških metala čiji uzrok možemo tražiti u prirodi ili antropogenom djelovanju. Teški metali su, po definiciji, elementi gustoće veće od 5 g/cm 3 . Dok neki mogu biti osnovni nutrijenti, ostali mogu biti otrovni. Oni u ljudskom organizmu izazivaju razne poremećaje karcinogene i nekarcinogene prirode, a može doći do trovanja konzumiranjem hrane biljnog podrijetla. Kroz zakonsku regulativu je propisana dozvoljena količina teških metala u istoj. Do apsorpcije i skladištenja teških metala iz tla u biljke dolazi putem niza transportnih mehanizama koji inače služe za apsorpciju mikronutrijenata. Različite biljne vrste imaju i različita apsorpcijska svojstva, radi čega je važno definirati faktor prijenosa koji označava odnos koncentracije teških metala u biljkama i one u odgovarajućem tlu. Da bi ga odredili u istraživanju je važno uzeti u obzir i analizu tla koja je, kao i analiza biljnih materijala, propisana određenim protokolima koji slijede iz zakonske rgulative. Priprema uzoraka se može odvijati na dva načina: mokrim i suhim razaranjem, od kojih obje imaju svoje prednosti i nedostatke. Pripremljeni uzorci dalje se analizira različitim instrumentnim tehnikama, najčešće AAS - om, ICP - MS - om, ICP - AES - om ili HG - AFS - omHigher concentrations of heavy metals are present in nature, the cause of which can be found in nature or anthropogenic activity. Heavy metals are, by definition, elements with a density greater than 5 g / cm 3 . While some can be essential nutrients, others can be toxic. They cause various disorders of carcinogenic and non- carcinogenic nature in the human body, and poisoning can occur by consuming food of plant origin. The legal regulations prescribe the permitted amount of heavy metals in it. The absorption and storage of heavy metals from the soil into plants occurs through a series of transport mechanisms that otherwise serve to absorb micronutrients. Different plant species also have different absorption properties, which is why it is important to define a transfer factor that indicates the ratio of the concentration of heavy metals in plants and those in the corresponding soil. In order to determine it, it is important to take into account the analysis of the soil, which, as well as the analysis of plant materials, is prescribed by certain protocols and the regulations. Sample preparation can be performed in two ways: wet and dry destruction, both of which have their advantages and disadvantages. The prepared samples can be analysed by different instrumental techniques such as AAS, ICP - MS, ICP - AES or HG - AFS
Comparison of spectrophotometric and potentiometric determination of biologicall active substances in pharmaceuticals - review : bachelor thesis
No full textCilj ovog završnog rada bio je pregledati noviju literaturu spektrofotometrijskih i potenciometrijskih određivanja biološki aktivnih tvari u farmaceuticima. Isto tako, usporediti spektrofotometrijska i potenciometrijska mjerenja različitih autora. Aktivne farmaceutske tvari(API) obrađene u znanstvenim radovima su metformin, bupropion hidroklorid i difenhidramin. Ispitana je valjanost izvornih UV- i izvedenih UV-spektrofotometrijskih metoda s obzirom na preciznost, raspon linearnosti, točnost, granicu detekcije i granicu kvantifikacije. Načinjene su krivulje pH vrijednosti u odnosu na dodani volumen titranta pri potenciometrijskim titracijama. U pregledanim radovima potenciometrijska metoda daje bolju točnost i bolju preciznost od spektrofotometrijske, ali do koncentracija reda veličine 10 -5 M. Međutim, UV-VIS spektrofotometrija omogućava određivanje nižih koncentracija opisanih tvari.The aim of this final paper was to review the new literature on spectrophotometric and potentiometric determinations of biologically active substances in pharmaceuticals. Also, to compare spectrophotometric and potentiometric measurements of different authors. The active pharmaceutical ingredients(APIs) processed in scientific papers are metformin, bupropion hydrochloride and diphenhydramine. The validity of original UV and derived UV spectrophotometric were examined with respect to precision, linearity range, accuracy, detection limit and quantification limit. Curves of pH values in relation to the added volume of titrant were made during potentiometric titration. In these works, the potentiometric method gives the best accuracy than the specrophotometric one. However, UV- VIS spectrophotometry can handle compounds with lower solubility and lower sample concentrations
Chemical analysis of volatile compounds of craft beer ''Mrka'' : bachelor thesis
No full textU ovom radu analiziran je kemijski sastav hlapljivih spojeva craft piva „Mrka“. Tijekom proizvodnje craft piva „Mrka“ dodani su začini poput metvice, cimeta, muškatnog oraščića i čokolade radi poboljšanja mirisa i okusa piva. Hlapljivi spojevi izolirani su dvjema različitim metodama: mikroekstrakcijom vršnih para na krutoj fazi (HS-SPME) s dva različita vlakna te kontinuiranom ekstrakcijom tekuće-tekuće s organskim otapalom te su analizirani spregnutom tehnikom plinska kromatografija–spektrometrija masa (GC-MS) u cilju usporedbe sličnosti i razlika dobivenih rezultata. SPME metodom identificirano je 37 različitih spojeva dok je kontinuiranom ekstrakcijom tekuće-tekuće identificirano njih 23. Identificirani spojevi mogu se svrstati u sljedeće kemijske skupine: alkoholi, esteri, alkaloidi, terpenski spojevi i ketoni.In this paper, the chemical composition of volatile compounds of craft beer "Mrka" is analyzed. During the production of craft beer "Mrka", spices such as mint, cinnamon, nutmeg and chocolate were added to improve the smell and taste of beer. The volatile compounds were isolated by two different methods: solid phase peak extraction microextraction (HS-SPME) with two different fibers and continuous liquid- liquid extraction with an organic solvent, and were analyzed by the gas chromatography–mass spectrometry (GC-MS) conjugation technique for comparison. similarities and differences in the results obtained. 37 different compounds were identified by the SPME method, while 23 were identified by the continuous liquid-liquid extraction method. The identified compounds can be classified into the following chemical groups: alcohols, esters, alkaloids, terpene compounds and ketones
Microwave synthesis of aluminum oxide particles with different experimental conditions : diploma thesis
No full textAluminijev oksid (Al 2 O 3 ) ima široku primjenu u anorganskoj industriji zbog svojim izrazito povoljnih kemijskih i termičkih svojstava. Najpoznatija uporaba Al 2 O 3 je u procesu proizvodnje keramike (čisti Al 2 O 3 ili smjesa Al 2 O 3 i ZrC, ZnO 2 , SiC i dr.). Zbog svojih dobrih mehaničkih svojstava Al 2 O 3 se upotrebljava i kao abraziv te u staklenoj industriji kao vatrostalni materijal. Cilj ovog diplomskog rada je ispitati eksperimentalne uvjete sinteze (temperatura, utjecaj surfaktanta, vrijeme) čestica Al 2 O 3. U radu su primijenjene temperature sinteze u rasponu od 130°C do 250°C (130°C, 200°C i 250°C) za različito vrijeme sinteze od 20, 30 i 40 min i uz prisutnost miješanja ili bez miješanja tijekom mikrovalne sinteze. Od surfaktanata koji su korišteni, ispitan je utjecaj cetiltrimetilamonijeva bromida (CTAB) u količinama od 0,4 g i 1,0 g, polietilen glikola (PEG) u količinama 2 g, 1 g i 0,4 g, natrijva dodecil-sulfata (SDS) u količini od 1 g te N-gvanilurea sulfat u količini od 1 g. Svi uzorci snimljeni su IR-spektrometrom (FTIR). Odabrane uzorke, koji su pokazivali najbolje FTIR rezultate, žareni su pri temperaturama 400°C, 800°C i 1100°C. Duljina žarenja iznosila je 2 h odnosno 4 h.Due to its extremely favourable chemical and thermal properties, aluminum oxide has wide application in the inorganic industry. The most well-known use of Al 2 O 3 is in the process of ceramics production (as a pure Al 2 O 3 or as a mixture of Al 2 O 3 and ZrC, ZnO 2 , SiC etc.). Due to its good mechanical properties it is also used as an abrasive, but also in the glass industry as a refractory material. The goal of this master thesis is to examine the experimental conditions (synthesis temperature, annealing temperature, surfactant effect, synthesis time, mixing effect etc.) that would be most optimal for obtaining Al 2 O 3 particles. The thesis uses synthesis temperatures ranging from 130°C to 250°C (130°C, 200°C and 250°C) for different synthesis times (20 min, 30 min, 40 min) and the presence or the absence of mixing during microwave synthesis. Of the surfactants that were used, the influence of cetyl trimethylammonium bromide (CTAB) in quantities of 0,4 g and 1,0 g, polyethylene glycol in quantities of 2,0 g, 1,0 g and 0,4 g, sodium dodecyl sulfate in quantities of 1,0 g and N-guanylurea sulfate in quantities of 1,0g was examed. All sample were analyzed by FTIR. Selected samples, which had showed the best FTIR results, were subjected to the annealing process at respective temperatures of 400°C, 800°C and 1100°C. The annealing lenght was 2 h at 400°C and 4 h for annealing at 800°C and 1100°C, respectively