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Prilog kinematičkoj sintezi mehanizama u sistemima oslanjanja motornih vozila / A contribution to the kinematical synthesis of motor vehicle suspension mechanismsPoznanović Nenad 19 September 2016 (has links)
<p>U radu je razmatran problem projektovanja polužnih mehanizama koji se primenjuju u sistemima elastičnog oslanjanja drumskih vozila.<br />Polužni mehanizmi za vođenje točka imaju zadatak da ostvare pokretnu vezu točka sa nosećim strukturama vozila koja omogućava približno vertikalno relativno kretanje točka u odnosu na telo vozila i obezbeđuje prijem aktivnih i reaktivnih sila i momenata nastalih u interakciji točka sa podlogom.<br />Definisana je jednostavna, univerzalna metoda za optimalnu sintezu mehanizama u sistemima oslanjanja vozila, koja ne zahteva pripreme i prilagođavanje različitim specifičnim uslovima i zahtevima sinteze mehanizama u okvirima ove tematike. Osnovne karakteristike predloženog postupka su: tačnost i praktična primenljivost usvojenog metodološkog prilaza; jednostavnost i univerzalnost celokupnog postupka sinteze, osigurana usvajanjem algoritma diferencijalne evolucije kao optimizacione metode; robusnost metoda i odsustvo potrebe za pripremom i prilagođavanjem različitim postavkama problema sinteze; implementacijom postupka u okruženju opšteg matematičkog programa Mathcad omogućeno je da svi elementi proračuna (ulazni podaci, jednačine, komentari, skice, dijagramski prikazi i numerički rezultati) budu objedinjeni na jednom mestu.Primena razvijenog postupka sinteze demonstrirana je na karakterističnim problemima optimalne sinteze mehanizama za oslanjanje vozila. Problemi su postavljeni tako da je zadato kretanje nosača točka - generisano je mehanizmom poznate konfiguracije. U takvoj postavci problema, u kojoj se pouzdano zna da se zadato kretanje nosača točka može ostvariti, izvedeni su numerički eksperimenti sa višestrukim ponavljanjem postupka sinteze uz variranje početnih vrednosti nepoznatih konstrukcionih parametara slučajnim izborom iz širokih intervala. Dobijeni rezultati su pokazali da je u svim slučajevima razvijeni postupak sinteze rezultovao mehanizmom koji ostvaruje zadato kretanje uz odstupanja znatno ispod praga fizičke značajnosti.</p> / <p>This paper is focused on the design of lever mechanisms used in systems for elastic vehicle suspension.<br />The lever mechanisms used for wheel guidance are tasked with accomplishing a mobile connection between the wheel and the support structure that allows the wheel a roughly vertical motion relative to the vehicle body and receives the active and reactive forces and torque originating from the interaction between the wheel and the ground.<br />A simple, universal method for the optimal synthesis of mechanisms used in vehicle support systems is defined, one that doesn’t require extensive preparation or adjustments for specific conditions. The basic characteristics of the proposed method are: accuracy and practical applicability of the method; simplicity and universality of the whole synthesis process, insured by adopting the differential evolution algorythm for the optimization method; robustness of the method and the lack of need for preparation and adjustments to the different synthesis peoblems; by implementing the method in the universal mathematical program Mathcad, the calculation elements (input, equations, comments, sketches, diagrams and numerical resuts) are all presented and accessible in one place.<br />The application of the developed method is demonstrated on charachetirstic problems of the optimal synthesis of vehicle support mechanisms. The problems are set up so that the motion of the wheel support is known – it is generated by a mechanism with a known configuration. In this kind of setting, where one is sure the given motion of the wheel support can be accomplished, a series of numerical tests was performed with multiple repetitions of the synthesis method using different initial values of the unknown construction parameters randomly chosen from wide intervals. The results of these experiments have shown that for each set of initial values, the developed method resulted in a mechanism that accomplished the required motion with very slight deviations, too small to be of any practical importance.</p>
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Perkolacioni procesi pri polimerizaciji olefina pomoću jedinjenja prelaznih metala / Percolation Processes in Olefin Polymerization with Transition MetalsPilić Branka 12 January 2006 (has links)
<p>Prema postojećem tumačenju Ziegler-Natta polimerizacije, smatra se da se prekursor prelaznog metala (Mt) aktivira pomoću alkila metala, a da se rast polimernog lanca ostvaruje umetanjem monomera između Mt i rastućeg polimernog lanca. Postoje mnoga neslaganja eksperimentalnih činjenica sa tumačenjem polimerizacije mehanizmom insertacije. U ovom radu predložen je novi mehanizam polimerizacije olefina pomoću jedinjenja prelaznih metala perkolacijom naelektrisanja (CPM): makromolekulski lanac nastaje polimerizacijorm grozda monomera (nM) koji je adsorbovan na nosaču (S) između dva adsorbovana prelazna metala, jednog u višem (Mt<sup>+4</sup>), a drugog u nižem oksidacionom stanju (Mt<sup>+2</sup>):</p><p style="text-align: center;">( Mt<sup>n+1...</sup>nM<sup>...</sup>Mt<sup>n+1</sup>)/S →(Mt<sup>n</sup>Mt<sup>n</sup>)/S + polimer.</p><p>Novi mehanizam polimerizacije perkoracijom naelektrisanja potvrđen je eksperimentalnim podacima, matematičkim proračunima i kompjuterskim simulacijama. U radu je prvo ukazano na značaj dosadašnjih istraživanja i dat je prikaz pojedinih eksperimentalnih činjenica koje potvrđuju perkolacioni model polimerizacije. Po principu Monte-Carlo simulacija, napravljen je novi specijalni kompjuterski program "Lattice" koji omogućuje simulaciju polimerizacije olefina pomoću CPM. U radu je dat detaljan opis kompjuterskog programa "Lattice" i ojašnjeno je na koji način se eksperimentalni parametri prevode u parametre perkolacionog modela polimerizacije. Na osnovu matematičkog proračuna i kompjuterske simulacije (primenom teorije Kobozeva) predviđen je uticaj sadržaja prelaznog metala na nosaču na produktivnost metala i nosača, što je potvrđeno eksperimentalnim podacima. U radu je prikazano na koji način promene: tipa nosača, početne površinske koncentracije monomera, koncentracije prelaznim metala redosledu dodavanja reagujućih komponenti, utiču na grafiku brzina polimerizacije - vreme. Primenom perkolacionog modela polimerizacije objašnjene su eksperimentalne činjenice koje do sad nisu mogle biti potpuno objašnjene primenom mehanizma insertacije.</p> / <p>According the current explanation of Ziegler-Natta polymerization, transition metal (Mt)<br />is activated by alkyl group and vacant orbital are formed. It is belived that polymer<br />chain propagates by monomer insertion between Mt and growing polymer chain. It has also been known that by using existing insertion mechanism of the polymerization,<br />some experimentally proved facts cannot be explained completely. In this paper new<br />charge percolation mechanism (CPM) of olefin polymeiization by supported Mt<br />complexes is presented: a macromolecular chain is formed polymerization of<br />monomer cluster (nM) adsorbed at the support (S) between two immobilised Mt ions,<br />one in the higher (Mt<sup>+4</sup>) and the other in the lower (Mt<sup>+2</sup>) oxidation state:</p><p style="text-align: center;">( Mtn+1...nM...Mtn+1)/S →(MtnMtn)/S + polymer.</p><p>New CPM has been confirmed by published experimental data, by calculating and by computer simulation. First it has been clarified the signifigance of the existing<br />experiment and some experimental facts wich are confrlmed by CPM are shown. A special computer program "Lattice" has been developed to simulate olefin<br />polymerization based on CPM using Monte Carlo procedure. In this work it is explanied<br />how the polymerization parametar from real experiments are transfered to percolation<br />and simulation parametars. The effects of thesurface concentration of active centres on<br />metal productivities and support productivites has been predicted by the calculating and computer simulation (using catalytic theory of Kobozev) and confirmed by real<br />experimental data. In this work it is also shown how the polymer structure and tipe of<br />the curve polymerization rate/time depend on reaction conditions (Mt concentration, tipe of the support, Mt/S ratio, sequence of chemical components addition, time). At the end the experimental facts which couldn't have been explained completaly ty insertion<br />mechanism are explanied using CpM.</p><p style="text-align: center;"> </p>
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Dijagnostika oštećenja i procena preostalog životnog veka cevi etilenskih peći / Failure diagnostics and remaining lifeprediction of ethylene furnace tubeKucora Ištvan 29 September 2016 (has links)
<p>Disertacija je posvećena problemima<br />oštećenja cevi pirolitičkih peći u fabrici etilena,<br />kao i metodima procene preostalog ţivotnog<br />veka cevi peći, uopštava teorijska i praktična<br />istraţivanja koja su sprovedena za vreme<br />trajanja doktorskih studija.<br />Peć za pirolizu benzina je uzeta kao tipičan<br />primer za proučavanje preostalog ţivotnog veka<br />na osnovu prikupljenih podataka o cevima peći,<br />kao što su: redukcija debljine zida, povećanje<br />spoljnjeg prečnika, tvrdoća i metalografska<br />istraţivanja, itd., a eksperimentalni rezultati su<br />dobiveni iz pripremljenih isečaka cevi peći.<br />Razmatra se veliki kompleks pitanja povezan<br />sa problemom tačnosti procene ţivotnog veka.<br />Iako otkaz cevi peći nije veliki bezbednosni<br />problem, procena preostalog ţivotnog veka cevi<br />je značajna zbog uštede troškova koji proizilaze<br />iz optimizacije procesnih parametara ili<br />redukcije frekvence ispitivanja i prevazilaţenja<br />neplaniranih zastoja.</p> / <p>The dissertation is devoted to<br />problems of pyrolysis furnace tubes<br />damage in ethylene plant, and methods of<br />assessment of the furnace tube remaining<br />life, generalizes the theoretical and<br />practical research that is conducted during<br />the doctoral studies.<br />Furnace for the gasoline pyrolysisis<br />taken as a typical example for the study of<br />the remaining life based on data collected<br />on the furnace tube, such as the reduction<br />of wall thickness, increasing the outer<br />diameter, hardness and metallographic<br />testing, etc.., and experimental results<br />were obtained from prepared furnace tube<br />slices.<br />Discusses the major issues associated<br />with the complex problem of the accuracy<br />of life expectancy. Although furnace tube<br />failure isn’t a major security problem, the<br />tube remaining life estimation is important<br />because of cost savings resulting from the<br />optimization of process parameters or<br />reducing the frequency of tests and<br />overcome unplanned downtime.</p>
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Sinteza, karakterizacija i primena sorbenata na bazi gvožđa i mangana za uklanjanje arsena iz vode / Synthesis, characterisation and application iron and manganeous based sorbents for arsenic removal from waterNikić Jasmina 12 July 2019 (has links)
<p>Prisusutvo arsena u podzemnim vodama, koje se primenjuju za vodosnabdevanje stanovništva je globalan problem. Različiti konvencionalni<br />procesi se primenjuju za uklanjanje arsena iz vode, uključujući koagulaciju i<br />flokulaciju, sorpciju, membransku filtraciju i jonsku izmenu. Uzimajući u<br />obzir relativnu nisku cenu, jednostavnu kontrolu procesa i održavanje, visok<br />stepen uklanjanja arsena, sorpcija se smatra jednom od najpodobnijih tehnika<br />za uklanjanje arsena u tretmanu vode za piće. Premda su na tržištu dostupni<br />različiti sorbenti za uklanjanje arsena, postoji potreba za iznalaženjem i<br />razvojem novih <em> low-cost </em> sorbenata, a kojima bi se pak mogao obezbediti<br />visok stepen uklanjanja oba oksidaciona oblika arsena, i As(III) i As(V). Cilj<br />ovog rada bio je usmeren na sintezu i karakterizaciju novih sorbenata na bazi<br />gvožđa i mangana odnosno Fe-Mn binarnog oksida, ispitivanje njihovog<br />potencijala za uklanjanje arsena iz vode i utvrđivanje da li novosintetisani<br />sorbenti po pitanju efikasnosti, mogu konkurisati postojećim komercijalnim i<br />široko korišćenim sorbentima u tretmanima voda.<br />Metodom precipitacije, sintetisani su Fe-Mn binarni oksidi sa različitim Fe:Mn molskim odnosima 1:1, 3:1, 6:1 i 9:1, dok su kombinacijom heterogene nukleacione tehnike i precipitacije, sintetisana i četiri sorbenta magnetnih svojstava (Mag, Mag-Fe, Mag-Mn, Mag-FeMn). Modifikacijom biopolimera Chitosana i GAC, sa Fe-Mn binarnim oksidom, razvijena su preostala dva materijala Chit-FeMn, odnosno GAC-FeMn. Sintetisani sorbenti su karakterisani različitim tehnikama i metodama (SEM/EDS, XRD,FTIR, BET).Fizičko-hemijskom karakterizacijom sintetisanih sorbenata ustanovljeno je da se Fe-Mn binarni oksidi i magnetni materijali, karakterišu relativno velikim specifičnim površinama (109-300 m<sup> 2 </sup>/g) i zapreminama mezopora (0,144-0,403 cm <sup>3</sup> /g). Velika specifična površina i razvijena mikroporozna struktura uočena je kod GAC-FeMn (996 m<br /><sup>2</sup> /g; 0,394 cm<sup> 3 /</sup>g). U poređenju sa ostalim sintetisanim sorbentima, Chit-FeMn je karakterisala najmanja specifična površina i zapremina mezopora (1,99 m<br /><sup>2 </sup>/g; 0,014 cm <sup>3</sup> /g). XRD analiza Fe-Mn binarnih oksida ukazala je da je fazna struktura sintetisanih Fe-Mn binarnih oksida slična ferihidratu dok je fazna struktura magnetnih materijala ukazala na prisustvo magemita.<br />Ispitivanja kinetike sorpcionog procesa ukazala su da je mehanizam sorpcije<br />As(III) i As(V) na sintetisanim sorbentima sloţena kombinacija površinske<br />hemisorpcije, koja se odvija kroz granični sloj čestica sorbenata i unutarčestične difuzije. Tome u prilog išli su i rezultati FTIR analize kojima<br />je potvrđeno da se sorpcija arsena na sintetisanim sorbentima ostvaruje kroz<br />interakcije hidroksilnih grupa gvožđa prisutnih na površini sorbenata i arsena.<br />Dodatno, pokazano je da se za razliku od sorpcije As(V), sorpcija As(III) na sorbentima koji pored oksida gvožđa sadrže i okside mangana (Fe-Mn binarni oksidi, Mag-FeMn, Mag-Mn,Chit-FeMn i GAC-FeMn) odvija u dva koraka. U prvom koraku As(III) se oksiduje do As(V), dok u drugom koraku, oksidovani As(V) mehanizmom ligandne izmene formira komplekse na površini ovih sorbenata.<br />Afiniteti sorpcije Fe-Mn binarnih oksida (na osnovu K<sub>d</sub> vrednosti) za As(III) opadali su u nizu Fe-Mn 3:1 > Fe-Mn 1:1 > Fe-Mn 6:1 > Fe-Mn 9:1 odnosno kod As(V): Fe-Mn 6:1 > Fe-Mn 3:1 > Fe-Mn 9:1 > Fe-Mn 1:1. Kod magnetnih kompozita, najveća K<sub>d</sub> vrednost za As(III) i As(V) ustanovljena je kod Mag-FeMn. Uopšteno, Kd<br />vrednosti za As(III), kod magnetnih kompozita, opadale su u nizu: Mag-FeMn > Mag-Mn > Mag > Mag-Fe, Slično, afinitet sorbenata za As(V), opadao je na sledeći način: Mag-FeMn > Mag > Mag-Fe > Mag-Mn. U poređenju sa neimpregniranim, K<sub>d</sub> vrednosti bile su daleko veće kod obloţenih materijala, Chit-FeMn i GAC-FeMn, što je ukazalo na značajan doprinos Fe-Mn binarnog oksida adsorpcionom kapacitetu neimpregniranih medija za As(III) i As(V). U odnosu na ostale ispitivane anjone, najveći uticaj na sorpciju oba oblika arsena na svim sintetisanim sorbentima uočen je kod fosfata, dok je uticaj nitrata i hlorida, u svim slučajevima bio bez značaja. Uticaj ispitivanih anjona na sorpciju As(III) i As(V) na Fe-Mn binarnim oksidima, magnetnim materijalima, Chit-FeMn kao i na sorpciju As(V) na GAC-FeMn, opadao je u nizu: fosfati > silikati > karbonati > sulfati > nitrati > hloridi. Slično, uticaj ispitivanih anjona na sorpciju As(III) na GAC-FeMn je opadao na sledeći način: fosfati > silikati > sulfati > karbonati > nitrati > hloridi.Primenom smeše NaCl-NaOH-NaOCl odnosno primenom 0,1 M i 0,5 M rastvora NaOH, ustanovljeno je da se sintetisani sorbenti mogu jednostavno i efikasno regenerisati i višestruko primeniti, što je od izuzetnog značaja sa ekološkog i ekonomskog aspekta. Najmanje smanjenje sorpcionog kapaciteta i za As(III) i za As(V), nakon pet ciklusa sorpcije -desorpcije, ustanovljeno je kod binarnog oksida sa Fe:Mn molskim odnosom 3:1 i Mag-FeMn. Na osnovu rezultata prikazanih u ovom radu, može se zaključiti da sintetisani sorbenti, Fe-Mn binarni oksidi i magnetni kompoziti, posebno Mag-FeMn, mogu biti efikasna i ekonomična alternativa skupim komercijalnim sorbentima i drugim sofisticiranim tehnologijama. Visok oksidacioni i sorpcioni kapacitet ovih materijala, koji obezbeđuje istovremeno uklanjanje oba oksidaciona oblika arsena daje veliku prednost ovim sorbentima i čini ih veoma atraktivnim i obećavajućim u tretmanu voda. Dodatni benefit<br />magnetnih sorbenata, pre svega Mag-FeMn, ogleda se u njegovoj jednostavnoj separaciji iz vodenog medijuma i recirkulaciji u sistemu. Glavne prednosti sintetisanih Chit-FeMn i GAC-FeMn, ogledaju se u mogućnosti njihove primene kao efikasne filtracione ispune.</p> / <p>The presence of inorganic arsenic in groundwater used for drinking water supply is a global problem. Different techniques such as oxidation, coagulation, adsorption, ion exchange, and membrane filtration have been developed and applied for arsenic removal from aqueous media. Among these technologies, adsorption is regarded as one of the most promising approaches to remove arsenic from water because of its high efficiency, low cost, simplicity of operation. Although many sorbents for arsenic removal are available on the market, there is still a need to identify and develop new lowcost sorbents which are highly effective in removing both oxidation states of arsenic, As(III) and As(V). This dissertation therefore presents the synthesis and characterization of ten new iron and manganese based sorbents specifically developed for effective As removal. The Fe- Mn binary oxides were prepared with Fe:Mn molar ratios of 1:1, 3:1,6:1 and 9:1, while four heterogeneous magnetic composites (Mag, Mag-Fe,Mag-Mn, Mag-FeMn) were synthesized by combining the heterogeneous nucleation technique with precipitation. The remaining two materials, Chit-FeMn and GAC-FeMn, were created by modifying the Chitosan and GAC biopolymers with Fe-Mn binary oxide (Chit-FeMn and GAC-FeMn).Multiple techniques were applied to determine the physical and chemical characteristics of the resulting sorbents (including SEM/EDS, XRD, FTIR and BET analyses). In order to establish which sorbents show the greatest promise for application during drinking water treatment, the sorption capacity of the sorbents, theAs(III) and As(V) sorption mechanisms, and the impact of various factors relevant to arsenic sorption, including the regeneration potential and the reuse potential of the sorbents, were all investigated in batch experiments. During the physical characterisation, the Fe-Mn binary oxides and magnetic materials were found to have relatively large specific surface areas (109-300 m 2 /g) and mesopore volumes (0.144-0.403 cm 3 /g). A large specific surface area and microporous structure was observed for GAC-FeMn (996 m 2 /g; 0.394 cm 3 /g). In comparison with the other synthesized sorbents, Chit-FeMn has the smallest specific surface area and pore volume (1.99 m 2 /g; 0.014 cm 3 /g). XRD analyses of the Fe-Mn binary oxides indicated that the phase structure of the synthesized Fe-Mn binary oxides was similar to ferrihydrate, while the phase structure of the magnetic materials showed a good agreement with the XRD diffractogram of maghemite. Investigations into As sorption process kinetics have shown that the sorption mechanism for both As(III) and As(V) on the synthesized sorbents is a combination of surface hemisorption, which takes place through the boundary layer of sorbent particles, and intracellular diffusion. The FTIR analyses confirmed that arsenic sorption was accomplished through the interactions of the hydroxyl groups of iron present on the surface of the sorbents and arsenic. In contrast to the sorption of As(V), it was also shown that As(III) sorption onto sorbents containing manganese oxides (Fe-Mn binary oxides, Mag-FeMn, Mag-Mn, Chit-FeMn and GAC -FeMn) takes place in two steps. In the first step As(III) is oxidized to As(V), while in the second step, the oxidized As(V) forms complexes on the surface of the sorbents via ligand exchange. The Fe-Mn binary oxide sorption capacities (expressed as Kd values) for As(III) followed the trend Fe-Mn 3:1 > Fe-Mn 1:1 > Fe-Mn 6:1 > Fe-Mn 9:1, whereas the As(V) trend was Fe-Mn 6:1 > Fe-Mn 3:1 > Fe-Mn 9:1 > Fe-Mn 1:1. In the magnetic composites, the largest Kd value for As(III) and As(V) was obtained for Mag-FeMn. Generally, the Kd values for As(III) in the magnetic composites decreased in the series: Mag-FeMn > Mag-Mn > Mag > Mag-Fe. Similarly, the affinity of the sorbents for As(V) was as follows: Mag-FeMn > Mag > Mag-Fe > Mag- Mn. In comparison to the nonimpregnated materials, the Kd values were much higher for the boated materials, Chit-FeMn and GAC-FeMn, demonstrating the significant advantage Fe-Mn binary oxides provide in increasing As(III) and As(V) adsorption capacities. One of the most problematic limiting factors in applying adsorption technologies during drinking water treatment is the presence of other water constituents which interfere with the adsorption process. Investigations into the inhibitory effect of competive anions on the adsorption of both forms of arsenic revealed that phosphates were the worst offenders in terms ofreducing the arsenic removal efficacy of sorbents investigated. From the largest to the smallest negative influence of the anions investigated, for As(III) and As(V) adsorption on Fe-Mn binary oxides, magnetic materials and Chit-FeMn, as well as As(V) adsorption on GAC-FeMn, the order was: phosphates > silicates > carbonates > sulfates > nitrates > chlorides, with the presence of the latter two anions proving almost irrelevant to the As adsorption process. Similarly, the negative influence of anions on As(III) sorption on GAC-FeMn was: phosphates > silicates > sulphates > carbonates > nitrates > chlorides. Another issue with applying adsorption in real treatment conditions is the need to regularly regenerate and/or replace the spent sorbent. In this work, a simple and efficient process for sorbent rfegeneration is demonstrated. This regeneration process can be applied to the sorbents investigated multiple times, and uses an NaCl-NaOH-NaOCl mixture, or 0.1 M and 0.5 M NaOH solutions. This finding is of great importance from an ecological and economic point of view. The minimum reduction in the sorption capacity for both As(III) and As(V), after five sorption-regeneration cycles, was found in the binary oxide with a 3:1 Fe:Mn molar ratio and Mag-FeMn. Arsenic sorption behaviour was also investigated using real groundwater samples, with the results demonstrating the great potential of 3:1 Fe-Mn binary oxide and Mag- FeMn. However, Chit-FeMn and GAC-FeMn were less effective at adsorbing As from the groundwater samples.Based on the results presented in this dissertation, it can be concluded that the synthesized sorbents, especially the Fe-Mn binary oxides and magnetic composites, and Mag-FeMn in particular, can be efficient and economical alternatives to expensive commercial sorbents and other sophisticated As removal technologies. The high oxidation and sorption capacity of these materials, which ensure the simultaneous removal of arsenic with both oxidation states, is a large advantage for these sorbents and makes them very attractive and promising for application in drinking water treatment. An additional benefit of the magnetic sorbents, primarily Mag-FeMn, is the ease with which they may be separated from the aqueous medium, allowing for simple recirculation within a system. Similarly, the main advantages of the synthesized Chit- FeMn and GAC-FeMn are reflected in their application as effective filtration media.</p>
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Fotolitička i fotokatalitička razgradnja odabranih psihoaktivnih komponenata lekova u vodenoj sredini / Photolytic and photocatalytic degradation of selected psychoactive drugs in aquatic environmentFinčur Nina 06 July 2018 (has links)
<p>Ispitana je direktna i indirektna fotoliza alprazolama (ALP) i amitriptilina (AMI)<br />primenom UV, vidljivog i simuliranog sunčevog zračenja (SSZ). Takođe, praćena je stabilnost vodenih rastvora ALP i AMI u mraku. U okviru ispitivanja fotokatalitičke razgradnje ALP,ispitana je efikasnost ZnO i TiO<sub>2 </sub>Degussa P25 primenom UV i SSZ. Takođe, proučavan je utica jmasene koncentracije fotokatalizatora, pH, kao i<br />uticaj hvatača radikala/šupljina i elektron-akceptora. Praćen je stepen mineralizacije<br />merenjem ukupnog organskog ugljenika i primenom jonske hromatografije. Takođe,<br />detaljno su ispitani reakcioni intermedijeri. Dalje,ispitano je ponovno korišćenje ZnO u tri uzastopna procesa razgradnje ALP. U cilju praćenja citotoksičnosti ALP, ispitan je in vitro rast dve ćelijske linije: Neuro-2a i MRC-5. Zatim,proučavana je efikasnost sintetisanih ZnO (ZnO modifikovani mlevenjem i kalcinacijom, ZnO dopirani jonima Mg(II), ternarni i mešani cink-kalaj-oksidi) i TiO<sub>2</sub> (anatas TiO<sub>2</sub> nedopirani i dopirani La(III)-jonima, brukitni TiO2) nanoprahova u razgradnji ALP primenom UV i SSZ. U okviru fotokatalitičke razgradnje AMI, ispitana je efikasnost razgradnje pri različitim eksperimentalnim uslovima (uticaj vrste fotokatalizatora i zračenja, masene koncentracije fotokatalizatora, početne koncentracije supstrata, uticaj prisustva kako hvatača radikala i šupljina, tako i elektron-akceptora). Praćen je stepen mineralizacije merenjem ukupnog organskog ugljenika i primenom jonske hromatografije. U cilju praćenja citotoksičnosti AMI, ispitan je in vitro rast četiri ćelijske linije: Neuro-2a, MRC-5, H-4-II-E i HT-29. Zatim, proučavana je efikasnost sintetisanih TiO<sub>2</sub>/polianilin nanokompozitnih prahova, kao i prevlaka čistog TiO<sub>2 </sub>i WO<sub>3</sub>/TiO<sub>2</sub> u razgradnji AMI primenom UV i SSZ. Takođe, ispitan je uticaj strukture supstrata na efikasnost fotokatalitičke razgradnje kroz ispitivanje efikasnosti sintetisanih TiO<sub>2</sub> nanoprahova dopiranih jonima W(VI), zatim mešanih cink-kalaj-oksid nanoprahova, kao i indijum-cink-oksid nanoprahova primenom UV i SSZ.</p> / <p>Direct and indirect photolysis of alprazolam (ALP) and amitriptyline (AMI) were studied using UV, visible, and simulated solar irradiation (SSI). Also, the stability of the ALP and AMI aqueous solutions in the dark were monitored. Photocatalytic degradation of ALP was studied in the presence of ZnO and TiO<sub>2</sub> Degussa P25 using UV and SSI. Also, the influence of the photocatalyst loading, pH, as well as the influence of the radical and holes scavengers and electron acceptors were studied. The degree of mineralization was monitored by measuring of total organic carbon and using ion chromatography. Also, reaction intermediates were examined in detail. Further, reusabillity of ZnO was investigated in three consecutive degradation processes of ALP. In order to get insight into the cytotoxicity of the ALP and intermediates formed during photocatalytic degradation, their influence on the growth of two cell lines: Neuro-2a and MRC-5 were investigated. Then, the efficacy of synthesized ZnO (ZnO modified with milling and calcination, ZnO doped with Mg(II) ions, ternary and coupled binary tin-zinc-oxide) and TiO<sub>2</sub> (anatase TiO<sub>2</sub> undoped and doped with La(III) ions and brookite TiO<sub>2</sub>) nanopowders in ALPdegradation using UV and SSI were investigated. Within the photocatalytic degradation of AMI, the degradation efficiency under different experimental conditions was studies (influence of the photocatalyst and irradiation type, photocatalyst loading, initial substrate concentration, the effect of the presence of radical and holes scavengers, and electron acceptors). The degree of mineralization was monitored by measuring of total organiccarbon and using ion chromatography. In order to study the cytotoxicity of AMI and degradation intermediates, their influence on the growth of four cell lines: Neuro-2a, MRC-5, H-4-II-E, and HT-29 were investigated. Then, the efficacy of synthesized TiO2/polyaniline nanocomposite powders, as well as photocatalysts of pure TiO<sub>2</sub> and WO<sub>3</sub>/TiO<sub>2</sub> in the form of films in AMI degradation using UV and SSI were studied. In addition, the effect of the substrate structure on the efficiency of photocatalytic degradation was studied by testing the activity of synthesized TiO<sub>2 </sub> nanopowders doped with W(VI) ions, then coupled binary tin-zinc- oxide nanopowders, as well as coupled binary indium-zinc- oxide nanopowders using UV and SSI.</p>
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Fotokatalitička stabilnost odabranih aktivnih komponenata kardiovaskularnih lekova: kinetika, mehanizam i toksičnost intermedijera / Photocatalytic stability of selected active components of cardiovascular drugs: kinetics, mechanism and toxicity of the intermediatesArmaković Sanja 01 July 2016 (has links)
<p>Ispitana je direktna i indirektna razgradnja odabranih β-blokatora (metoprolol- tartarata, MET i propranolol-hidrohlorida, PRO) kao i diuretika (hidrohlortiazida, HCTZ) i njegovog stabilnog intermedijera hidrolize 4-amino-6-hlor-1,3-benzendisulfonamida (ABSA). Praćena je i kinetika razgradnje direktnom i indirektnom fotolizom uz primenu UVA, UVC, sunčevog i simuliranog sunčevog zračenja (SSZ). Najpre je ispitana stabilnost MET pod dejstvom SSZ, UVA, UVC, UVA/H<sub>2</sub>O<sub>2 ,</sub> i UVA/ BrO<sub>3</sub><sup>-</sup>. Dalje je ispitana efikasnost razgradnje MET pod dejstvom O<sub>3</sub>i UVC/O<sub>3.</sub> Identifikovano je deset intermedijera tokom UVC, O<sub>3 </sub>i UVC/O<sub>3</sub> razgradnje, pri čemu samo jedan ima značajno višu toksičnost prema algama i bakterijama u odnosu na ostale. Efikasnost fotokatalitičke razgradnje MET je ispitana u TiO<sub>2</sub> suspenzijama sa komercijalnim katalizatorima (Wackherr i Degussa P25). Mehanizam fotokatalitičke razgradnje je detaljno ispitan, pri čemu je identifikovano četrnaest intermedijera. EC<sub>50</sub> vrednost MET i njegovih smeša nastalih pri fotokatalitičkoj razgradnji su određene na tri ćelijske linije sisara (H-4-II-E, HT-29 i MRC-5). Kako bi se povećala efikasnost rocesa fotokatalitičke razgradnje primenom komercijalnih katalizatora, ispitan je uticaj prisustva elektron-akceptora u suspenziji, pri čemu je upoređen uticaj O<sub>2</sub>/H<sub>2</sub>O<sub>2</sub>, i O<sub>2</sub>/ BrO<sub>3</sub><sup>-</sup> na mehanizam razgradnje. Na osnovu teorije funkcionala gustine stekao se uvid u promene unutar molekula MET u prisustvu reaktivnih radikala. Takođe, ispitana je efikasnost nedopiranih TiO<sub>2</sub> , kao i dopiranih La(III) nanoprahova sintetisanih sol−gel postupkom, u razgradnji MET. Uticaj temperature kalcinacije na fotokatalitičku efikasnost TiO 2 nanoprahova dopiranih pomoću La(III) ispitana je na supstratima MET i PRO, pri čemu je analiziran i uticaj strukture polaznog jedinjenja na informacija efikasnost fotokatalitičke razgradnje. Rezultati su upoređeni sa nedopiranim TiO<sub>2 </sub>nanoprahom i TiO<sub>2 </sub>Degussa P25 (pri pH-vrednosti 9). Pored toga, ispitana je kinetika i toksičnost PRO i njegovih intermedijera nastalih tokom razgradnje sa TiO<sub>2 </sub>Degussa P25. Ispitan je i uticaj strukture polaznog jedinjenja (MET, HCTZ i ABSA) na fotorazgradnju pod dejstvom UVA, sunčevog i simuliranog sunčevog zračenja, u odsustvu/prisustvu TiO<sub>2</sub> Degussa P25. Takođe, ispitan je i sinergistički efekat MET i ABSA na proces hidrolize, direktne fotolize i fotokatalize sa SSZ/TiO<sub>2 </sub>Degussa P25. Kako bi se stekao uvid u toksičnost proučavanih sistema, ispitan je njihov uticaj na rast odabranih ćelijskih linija sisara.</p> / <p>Direct and indirect degradation of selected β-blockers (metoprolol tartrate, MET and propranolol hydrochloride, PRO) and also diuretic (hydrochlorothiazide, HCTZ) in addition to its stable hydrolysis intermediate 4-amino-6-chloro- 1,3-benzenedisulfonamide (ABSA) were investigated. The kinetics of their degradation obtained by direct and indirect photolysis under UVA, UVC, sunlight and simulated sunlight irradiation (SSI) have been followed. Firstly, the stability of MET under influence of SSI, UVA, UVC, UVA/H<sub>2</sub>O<sub>2</sub> , and UVA/ BrO<sub>3</sub><sup>-</sup> has been investigated. Further, the efficiency of MET degradation under influence of O<sub>3</sub>, and UVC/O<sub>3</sub> has been explored. Ten intermediates have been identified during the UVC, O<sub>3</sub>, and UVC/O<sub>3</sub> treatments, while only one intermediate had significantly higher toxicity towards the algae and bacteria in respect to the others. Efficiency of photocatalytic degradation of MET was investigated in TiO<sub>2</sub> suspensions with commercial catalysts (Wackherr and Degussa P25). Mechanism of photocatalytic degradation was investigated in detail according to which fourteen intermediates were identified. EC 50 value of MET and its mixtures formed during the photocatalytic degradation has been determined at three mammalian cell lines (H-4-II-E, HT-29, and MRC-5). In order to improve the efficiency of photocatalytic degradation process applying commercial catalysts, the influence of presence of electron acceptors in suspension has been investigated and the influence of O<sub>2</sub>/H<sub>2</sub>O<sub>2 </sub>and O<sub>2</sub>/BrO<sub>3</sub><sup>-</sup> to the mechanism of degradation has been compared. Based on the density functional theory an insight to the changes within MET molecule in the presence of reactive radicals has been made. Also, the efficiency of bare TiO<sub>2</sub>, as well as doped La(III) nanopowders synthesized by sol-gel procedure, in the degradation of MET has been investigated. The influence of calcination temperature on hotocatalytic efficiency of TiO<sub>2 </sub>nanopowders doped with La(III) has been studied on the MET and PRO substrates, and the influence of structure of the starting compound on the efficiency of photocatalytic degradation had been analyzed. Results have been compared with bare TiO<sub>2 </sub>nanopowder and TiO<sub>2</sub> Degussa P25 (at pH value of 9). Besides, kinetics and toxicity of PRO and its intermediates formed during the degradation with TiO<sub>2</sub> Degussa P25 have been investigated. The influences of starting compound’s structure (MET, HCTZ, and ABSA) to photodegradation under UVA, sunlight and SSI, in the absence/presence of TiO<sub>2</sub> Degussa P25, have been investigated. Also, the synergistic effects of MET and ABSA to the process of hydrolysis, direct photolysis, and photocatalysis with SSI/TiO<sub>2</sub> Degussa P25 have been investigated. In order to get an insight into the toxicity of the studied systems, their influence on the growth of selected mammalian cell lines has been investigated as well.</p>
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Fotolitička i fotokatalitička razgradnja odabranih herbicida u vodenoj sredini / Photolytic and photocatalytic degradation of selected herbicides in aqueous mediaDespotović Vesna 10 July 2014 (has links)
<p>Ispitana je kinetika i mehanizam fotokatalitičke razgradnje herbicida kvinmeraka i klomazona u prisustvu UV/TiO<sub>2</sub> Degussa P25, odnosno piklorama i klopiralida <br />primenom UV/TiO<sub>2</sub> Wackherr pri različitim eksperimentalnim uslovima. Praćena je i kinetika razgradnje odabranih herbicida direktnom fotolizom uz primenu sunčevog, UV i vidljivog zračenja, kao i u odsustvu svetlosti. Pored toga, upoređena je efikasnost <br />UV/TiO<sub>2</sub> Degussa P25, odnosno UV/TiO<sub>2</sub> Wackherr sa vidljivim zračenjem, kao i direktnom fotolizom u prisustvu pomenutih izvora svetlosti. U cilju procene <br />citotoksičnosti klomazona i klopiralida, kao i smeše klomazona i klopiralida i njihovih intermedijera nastalih tokom fotokatalitičke razgradnje ispitan je in vitro rast <br />ćelijskih linija MRC-5 i H-4-II-E. Nakon ispitivanja fotokatalitičke razgradnje odabranih herbicida u dvaput destilovanoj vodi, praćena je njihova razgradnja i u prirodnim vodama. Takođe, ispitan je uticaj dodatka hidrogenkarbonata i huminske kiseline na efikasnost razgradnje odabranih herbicida. Fotokatalitička razgradnja klomazona, piklorama i mekopropa je ispitivana i u prisustvu UV/TiO<sub>2</sub> nanocevi. Aktivnost katalizatora TiO<sub>2 </sub>Wackherr i TiO<sub>2</sub> nanocevi je upoređena sa TiO<sub>2</sub> Degussa P25.</p> / <p>The kinetics and mechanism of photocatalytic degradation of the herbicides quinmerac and clomazone in the presence of UV/TiO<sub>2</sub> Degussa P25, and of picloram and clopyralid using UV/TiO<sub>2</sub> Wackherr under different experimental conditions were studied. The kinetics of degradation of selected herbicides by direct photolysis using sunlight, UV and visible radiation, and in the absence of light were followed. In addition, the efficiencies of UV/TiO<sub>2</sub> Degussa P25 and UV/TiO<sub>2 </sub>Wackherr were compared with visible radiation and direct photolysis in the presence of the above mentioned light sources. In order to evaluate the cytotoxicity of clomazone <br />and clopyralid alone and in their mixture with intermediates formed during the photocatalytic degradation, in vitro growth of cell lines, MRC-5 and H-4-II-E was followed. After examining the photocatalytic degradation of selected herbicides in double distilled water, their decomposition in natural waters was also followed. Also, the influence of hydrogencarbonate and humic acid addition on the efficiency of degradation of selected herbicides was studied. Photocatalytic degradations of clomazone, picloram and mecoprop were investigated in the presence of UV/TiO<sub>2 </sub>nanotubes. Activities of the catalysts TiO<sub>2</sub> Wackherr and TiO<sub>2 </sub>nanotubes were compared to TiO<sub>2</sub> Degussa P25.</p>
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