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Characterization of Hydophilicaly Modified Silicones
No full textOvaj rad opisuje karakteristike hidrofilno modificiranih silikona. Ukratko je opisano što su silikoni, kako se dobivaju i imenuju, te njihova svojstva i gdje se oni primjenjuju. Za izvođenje eksperimentalnog dijela korištena su dva uzorka silikona: LK-Ag-Platinum i LK- 7300 koji su dobiveni od tvrtke ELKAY SILICONES. Određivala se viskoznost otopina silikona različitih koncentracija. Analiza uzoraka izvršila se FTIR-spektroskopijom. Iako je FTIR analiza pokazala da su ispitivani uzorci gotovo identični, odnosno da posjeduju iste funkcionalne skupine, uočeno je da se viskoznost ispitivanih uzoraka značajno razlikuje. Pretpostavlja se da se radi o sličnim polimerima, a razlikuju se po molekulskoj masi ili u konformaciji.This work describes the characteristics of hydrophilicaly modified silicones. It briefly describes what silicones are, how to make them and name them, their properties and application. For the experiments, two samples of silicones were used: LK-Ag-Platinum and LK-7300, which were supplied by ELKAY SILICONES. The tests included viscosity measurements for aqueous silicone solutions of different concentrations. Analysis of samples was carried out also by FTIR spectroscopy. Although FTIR analysis showed that the test samples are almost identical, and that they have the same functional groups, it was observed that the sample viscosity is quite different. It can be assumed that the polymers are similar, but they differ in molecular weight or in the conformation
Analysis of Photochemical Pollution of the Adriatic Coast
No full textGlavni uzročnik fotokemijskog onečišćenja zraka je troposferski ozon koji ima štetno djelovanje na ljude i okoliš. Njegova koncentracija ovisi o primarnim onečišćivačima, odnosno o prekursorima iz kojih, kao sekundarni onečišćivač, nastaje. U ovom radu grafički su prikazani satni, dnevni i mjesečni prosjeci koncentracija ozona za 2013. godinu, za odabrane mjerne postaje duž Jadranske obale - Višnjan, Polača, Hum, Opuzen i Žarkovica. Također je prikazana i ovisnost koncentracije ozona o smjeru vjetra. Obradom podataka dobiveni su rezultati koji ukazuju na prisutnost dnevnog hoda prosječnih satnih koncentracija ozona u svim mjernim postajama. Također je, za sve mjerne postaje, na osnovi prosječnih dnevnih koncentracija ozona potvrđeno kako ozon ima svoj godišnji ciklus. Visoke koncentracije ozona tijekom ljetnih mjeseci povezuju se s visokim temperaturama u to doba godine, te povećanom koncentracijom primarnih onečišćivača usljed turističke sezone. Usporedbom dobivenih koncentracija ozona s meteorološkim parametrima (temperatura, vlažnost zraka, brzina i smjer vjetra) utvrđeno je da je ozon u pozitivnoj korelaciji s temperaturom te u negativnoj korelaciji s relativnom vlagom. Prikazana je i metodička obrada nastavne jedinice Ozon. Učenike je potrebno upoznati s fizikalnim svojstvima ozona te načinom njegova laboratorijskog dobivanja, objasniti nastanak ozona u troposferi i stratosferi te ukazati na važnost očuvanja okoliša i prirode.Tropospheric ozone is the main cause of photochemical air pollution and is harmful to people and the environment. Its concentration depends on the primary pollutants, precursors, from which ozone is produced as a secondary pollutant. Ozone concentrations in the lower layer of the troposphere are analyzed and presented as hourly, daily and monthly averages of ozone concentrations for 2013, for selected measuring stations along the Adriatic coast - Višnjan, Polača, Hum, Opuzen and Žarkovica. Dependence of ozone concentration on wind direction it has been observed as well. An annual cycle of ozone has been confirmed at all sites on the basis of the presence of diurnal average ozone concentration. High concentrations of ozone during the summer months are associated with seasonal high temperatures, and with increased concentration of primary pollutants connected to number of tourists. Comparing the ozone concentration with meteorological parameters such as temperature, relative humidity, wind speed and direction, it has been found that ozone is positively correlated with temperature and negatively correlated with the relative humidity. In accordance with teacher preparation requirements, a unit plan "The Ozone" has been prepared. Students need to know physical properties of ozone and how it is prepared in laboratory, to explain the formation of ozone in the troposphere and stratosphere and be aware of the importance of preserving the environment and nature
Effects of Anasthetics on Transmembrane Ion Channels
No full textCilj ovog rada je upoznati se sa temeljima anestezije, te mehanizmima djelovanja lokalne i opće anestezije na ionske kanale. U literaturnom pregledu opisana je povijest anestezije, razlike između lokalne i opće anestezije, te su ukratko objašnjeni osnovni pojmovi iz biokemije stanice, kao što su građa stanice, membrane te su opisane 3 vrste ionskih kanala, koji su glavna meta anestezijskog djelovanja. Opisano je molekularno djelovanje anestetika na ionske kanale, te na koje dijelove proteina djeluje anestezija. Pokazano je kako i lokalna i opća anestezija imaju različite mehanizme djelovanja, te također kako i anestetici iste vrste mogu imati različit mehanizam. U ovome radu se može vidjeti kako mehanizam djelovanja anestetika još nije u potpunosti razrađen, te da se mora još istraživati građa ionskih kanala i ostalih meta anestetika, kako bi se u potpunosti razjasnio način djelovanja anestezije.The goal of this thesis is to learn more about the foundations of anesthesia, and the mechanisms of action of local and general anesthesia on ion channels. History of anesthesia, the differences between local and general anesthesia were described, also key terms in cell biochemistry, like the cell structure, cell membranes, and 3 different kinds of ion channels, which are the main targets of anesthetic action, were introduced. Molecular action of anesthetics on ion channels was also described, as well as the protein parts susceptible to the action of anesthesia. Difference between the actions of local and general anesthesia were also discussed. Furthermore, it was shown how anesthetics of same class can have different mechanisms of action. This thesis also states that mechanisms of anesthetics are yet not fully understood and that the further research on structure of ion channels and other targets of anesthetics has to be carried out in order to fully elucidate mechanisms of actions of anesthetics
Determination of surfactant concentration in mouthnasm liquids
No full textU ovom radu govori se o određivanju koncentracije tenzida u tekućinama za ispiranje usta. Tenzidi su organske tvari koje karakterizira hidrofoban i hidrofilan dio molekule. One su sastavni dio brojnih sredstva za čišćenje, ali i sredstva za osobnu higijenu. Postoje četiri vrste površinski aktivnih tvari (kationske, anionske, neionske i amfolitske), a u sastavu ispitanih tekućina za ispiranje usta nalaze se kationski i amfolitski tenzidi. Ispitivane vodice za ispiranje usta u svom sastavu imaju amfolitski tenzid kokamidopropil betain (CAPB) ili kationski tenzid cetilpiridinijev klorid (CPC). Sva mjerenja vršena su direktnom potenciometrijom preko uređaja Metrohm i programa Tiamo. Analizirana su četiri uzorka vodica za ispiranje usta (MW1, MW2, MW3 i MW5). Uz titracije čistih uzoraka, napravljene su i titracije sa standardnim dodatkom (CPC). Koncentracija tenzida u uzorku MW1 iznosi 3,3428·10-3 moldm-3, u uzorku MW2 3,81416·10-3 moldm-3, u uzorku MW3 1,4041·10-3 moldm-3 i u uzorku MW5 5,5593·10-3 moldm-3. Točka ekvivalencije određena je instrumentalno. Koncentracije su određene računski na temelju dobivenih podataka. Rezultati su prikazani grafički u ovisnosti elektromotorne sile o volumenu utrošenog titranta (SDS).This paper deals with the determination of surfactants concentration in mouthwash liquids. Surfactants are organic matters which contain hydrophobic and hydrophilic part of molecule. They are main component in many cleaning personal hygiene products. There are four types of surfactants (cationic, anionic, nonionic and amphoteric), but only cationic and amphoteric surfactants are part of analyzed mouthwash liquids. Analyzed mouthwash liquids have amphoteric surfactant cocamidopropyl betaine (CAPB) or cationic surfactants cetylpyridinium chloride (CPC). All measurments were conducted by direct potentiometry with device Metrohm and softwere Tiamo. There were four samples of mouthwash liquids that were analyzed (MW1, MW2, MW3 and MW5). With titration of pure samples, there were also titration with known addition (CPC). The concetration of surfactant in sample MW1 is 3,3428·10-3 moldm-3, in sample MW2 3,81416·10-3 moldm-3, in sample MW3 1,4041·10-3 moldm-3 and in sample MW5 5,5593·10-3 moldm-3. Equivalent point was determined instrumentally. Concetrations are determined by obtained results. Results are presented by graphical representation of dependency electromotive force of spent titrant volume (SDS)
Temporal Varijations in Concentrations of Atmospheric Pollutants in the National park Kopački rit
No full textAtmosferski polutanti u graničnom sloju atmosfere imaju značajan utjecaj na sveukupni ţivot na Zemlji, uključujući učinak na zdravlje ljudi te ţivot pojedinih biljnih vrsta. MeĎu najznačajnijim polutantima ističe se ozon kao sekundarni polutant stvoren nizom reakcija iz primarnih polutanata (hlapljivi organski spojevi, dušikovi oksidi) koji izravno emisijom dospijevaju u atmosferu. U ovom radu prikazani su rezultati mjerenja koncentracija ozona u Parku prirode Kopački rit tijekom 2013. godine. Park prirode Kopački rit nalazi se u Baranji, na sjeveroistoku Hrvatske izmeĎu rijeka Drave i Dunava i jedna je od najvećih močvara u Europi. Mjerna postaja smještena je u Tikvešu. Mjerenja koncentracije ozona 2013. godine u Kopačkom ritu ukazala su na promjene koncentracija ozona s obzirom na mjerenja iz 2008. i 2013. godine. Analizom glavnih komponenata i izračunom korelacijskog koeficijenta utvrĎen je odnos izmeĎu koncentracije ozona i meteoroloških parametara. Veće koncentracije ozona su pri suhim i sunčanim vremenskim uvjetima. Metodički dio diplomskog rada sadrţi pripremu za nastavnu jedinicu pod naslovom Ozon. Nastavni sat je zamišljen kao kombinacija frontalnog rada i individualnog rada kojim bi učenici pomoću demonstracijskog pokusa samostalno zaključili koji je način dobivanja ozona te naučili nešto o njegovim svojstvima.Atmospheric pollutants in the boundary layer of the atmosphere have a major impact on life on Earth in general, which includes health effects and effects on a certain plant species. Ozone is one of the most significant pollutants which directly occur in atmosphere through emissions. It is formed through many reactions as a secondary pollutant from primary pollutants such as volatile organic compounds or nitrogen oxides. Survay of the ozone concentration for the 2013 th in the Nature Reserve Kopački rit is displayed in this thesis. The monitoring site was located near Tikveš. The Nature Reserve Kopački rit, located in Baranya, the far north-east of Croatia between the rivers of Drava and Danube is one of the largest natural marshlands in Europe. Measurements conducted in Kopački rit have shown a great diversity in ozone concentrations during the monitoring period. Principal component analysis and calculating the correlation coefficient was applied to provide the relationships between ozone concentrations and certain meteorological parameters. Higher ozone concentrations occurred in stagnant air under dry and sunny weather conditions. Methodic part of graduation thesis contain preparation for the teaching unit entitled Ozone. Lesson is designed as a combination of frontal lectures and individual work where students should independently conclude about ozone properties by means of experiment
Analysis of Photochemical Poiiution in Urban Areas of Republic of Croatia
No full textFotokemijsko zagađenje nastaje kao posljedica nagomilavanja štetnih tvari u troposferi iznad urbanih centara gdje su emisije prekursora dostatne da sinteza prevagne nad razgradnjom polutanata. Praćenje koncentracije ozona, kao glavnog sastojka fotokemijskog smoga, bitno je u zaštiti ljudskog zdravlja. Cilj ovog rada je utvrditi stupanj zagađenosti svakog od četiri urbana centra Republike Hrvatske; Osijek, Rijeka, Zagreb, Dubrovnik. Predmet obrade su validirani podaci Ministarstva zaštite okoliša i prirode. Zaključeno je da je Dubrovnik najzagađeniji, u kategoriju osrednje zagađenih pripadaju Rijeka i Osijek, dok je najslabije zagađen grad Zagreb.Photochemical pollution occurs as a result of accumulation of pollutants in the troposphere above urban centers where emissions of precursors seems to be sufficient for synthesis to outweigh decomposition of hazardous compounds. Monitoring concentrations of ozone, the main ingredient in photochemical smog, is important for protection of human health. The aim of this study was to determine degree of atmosphere contamination over four urban centers in the Republic of Croatia; Osijek, Rijeka, Zagreb, Dubrovnik. The subject of processing are validated data from the Ministry of Environmental and Nature Protection. The results show that Dubrovnik is the most polluted, in category of moderately polluted are Rijeka and Osijek, while the least polluted is city of Zagreb
Mehanokemijska sinteza Schiffovih baza
No full textZbog današnje potrebe za smanjenjem negativnih utjecaja na okoliš i količine otapala u kemijskim reakcijama sve se više okrećemo novim, alternativnim metodama dobivanja spojeva. Mehanokemijska sinteza je jedan od tih načina. Umjesto da se kemijske reakcije, kao što je to do sad bio običaj, izvode pomoću raznoraznih, najčešće organskih otapala koja mogu biti toksična, te podrazumijevaju velike unose energije i kasnije otpad koji treba zbrinuti, mehanokemija se javlja kao energetski učinkovita alternativa i omogućava istraživanje kemijskih reakcija bez upotrebe skupih i opasnih otapala. U ovome su radu mehanokemijskom sintezom pripravljene Schiffove baze izvedene iz dialdehida i diamina ručnim usitnjavanjem u tarioniku. Analiza produkata vršila se IR spektroskopijom i termičkom analizom pri čemu je ustanovljeno da je moguće dobiti željene produkte u visokom prinosu.Due to today's need to reduce negative impacts on the environment of solvents usage in chemical reactions we are increasingly turning to new alternative methods of preparing the compounds. Solvent free synthesis is one of those ways. Instead of chemical reactions, like it was the case so far, that are performed in various, mostly organic solvents, that are toxic and include large inputs of energy and subsequent waste that must be disposed of. Solvent free synthesis occurs as an energy efficient alternative that allows the study of chemical reaction without the use of expensive and hazardous solvents. Herein we demonstrate the classical solvent free synthesis of Schiff bases derived from dialdehyde and diamine by grinding in a mortar by hand. The prepared compounds were characterized by IR spectroscopy and thermal analysis (TGA-DSC) wherein is establish that it is possible to obtain the desired products in high yield
Analysis of data ozone in boindary layer atmosphere on the island Vis
No full textKoncentracija ozona u stratosferi rezultat je dinamičke ravnoteže između kemijskih procesa nastajanja te procesa njegove razgradnje. Prisutnost ozona u nižim slojeva atmosfere (troposfera) u obliku je fotokemijskog smoga koji narušava zdravlje i smanjuje vidljivost. Najvažniji učinak na ultraljubičasto zračenje ima ozon, a danas antropogeni faktori dovode do znatnih promjena ozona koje se očituju u stvaranju ozonskih rupa i fotosmoga. U ovom će se završnom radu analizirati uloga ozona u atmosferi, njegova obilježja prostorne raspodjele te godišnji hod. Na mjernoj postaji na otoku Visu (Hum) tijekom 2014. godine mjerena je koncentracija ozona. Mjerenje koncentracije ozona ima tipični godišnji hod s niskim zimskim vrijednostima i višim ljetnim vrijednostima zbog povećanog utjecaja Sunčevog zračenja koje sudjeluje u procesu stvaranja prizemnog ozona. Također, u dnevnom hodu koncentracije ozona izraženiji je jutarnji minimum i podnevni maksimum. Meteorološki parametri koji imaju najveći utjecaj na koncentraciju ozona su relativna vlažnosti i temperatura, a brzina vjetra i smjer vjetra nemaju veći utjecaj.Concentration of ozone in the stratosphere is a result of a dynamic balance between chemical processes of its formation and its destruction. The presence of ozone in the lower atmosphere (troposphere) is manifested in the form of photochemical smog that has a bad influence on health and reduces visibility. Ozone has the most important effect on ultraviolet radiation, and anthropogenic factors have lead to significant changes in ozone level, which are manifested in creating ozone holes and photochemical smog. In this thesis the role of ozone in the atmosphere, its characteristics of spatial distribution and the annual mean will be analyzed. During 2014, concentration of ozone at the Measuring station on the island of Vis (Hum) was measured. Typical annual mean of ozone concentration has low values in winter and higher values in summer because of increased influence of solar radiation that participates in the formation of ground-level ozone. Also, daily mean of ozone concentration has more stressed morning minimum and midday maximum. Relative humidity and temperature are meteorological parameters which have a great impact on ozone concentration while wind speed and direction don't have a momentous impact on ozone concentration
Influence of a Different Plasticizer on the Surfactant Electrode Properties
No full textIzrađene su membrane za ionsko-selektivne elektrode koje sadrže plastifikatore orto-nitrofenil-oktil eter (o-NPOE), dioktil ftalat (DOP), dioktil sebakat (DOS), 2-nitrofenil-fenil eter (NPPE), dibutil ftalat (DBP) i dibutil sebakat (DBS). Nakon sastavljanja elektroda ispitane su njihove odzivne karakteristike na kationske tenzide: cetilpiridinijev klorid monohidrat (CPC), heksadeciltrimetilamonijev bromid (CTAB), benzetonijev klorid (Hyamine 1622) i 1,3-didecil-2-metilimidazolijev klorid (DMIC). Osim odzivnih karakteristika na kationske tenzide ispitane su i odzivne karakteristike na anionske tenzide: natrijev dodecilsulfat (SDS) i natrijev dodecilbenzensulfonat (SDBS). Otopine kationskih i anionskih tenzida bile su u rasponu koncentracija od 4·10-2 do 4·10-4 mol dm-3. Odzivne karakteristike ispitivane su u destiliranoj vodi pri sobnoj temperaturi i bez promjene pH vrijednosti. Ionsko-selektivne elektrode čije membrane sadrže različite plastifikatore pokazale su različite odzivne karakteristike. Za istu vrstu tenzida elektrode su pokazale različitu selektivnost, granice detekcije i mjerno područje. Najbolje odzivne karakteristike, za sve vrste ispitivanih plastifikatora, pokazala je otopina kationskog tenzida Hyamine 1622. Odstupanje postoji jedino kod membrane koja sadrži DBS. Odzivi te membrane na otopine Hyamine 1622, CPC i CTAB nisu pogodni za daljnja istraživanja, a i sama membrana je mehanički nestabilna i kratkog vijeka trajanja. Ipak, s otopinom DMIC, te otopinama oba anionska tenzida ta membrana je pokazala zadovoljavajuće odzivne karakteristike. Rezultati istraživanja su pokazali da sastav membrane izravno utječe na njena senzorska svojstva za određivanje anionskih i kationskih tenzida. Metodički dio rada sadrži pripremu za nastavnu jedinicu pod naslovom Sapuni i detergenti. Nastavni sat je zamišljen kao kombinacija frontalnog i grupnog rada. Učenike je potrebno upoznati sa građom sapuna i detergenata te navesti njihova svojstva koja se ujedno dokazuju izvođenjem pokusa. Nakon izvođenja pokusa učenici popunjavaju radne listiće, a na kraju sata ponavlja se obrađeno gradivo.How to prepare membranes for ion-selective electrodes which contain plasticizers ortho-nitrophenyl octylether (o-NPOE), dioctylphthalate (DOP), dioctylsebacate (DOS), 2-nitrophenyl phenylether (NPPE), dibutylphthalate (DBP) and dibutylsebacate (DBS) has been shown in the thesis. The relevant electrode response characteristics to the cationic surfactant such as cetylpyridinium chloride monohydrate (CPC), hexadecyltrimethylammonium bromide (CTAB), benzethonium chloride (Hyamine 1622) and 1,3 -didecyl-2- methylimidazolium chloride (DMIC) are tested. The response characteristics to the anionic surfactant such as sodiumdodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS) were examined as well. The concentration range from 4·10-2 to 4·10-4 mol dm-3 was kept for both cationic and anionic surfactant solutions. The response characteristics were tested in destilled water at room temperature at constant pH. It has been obvious that ion-selective electrode response characteristics depend on applied membrane plasticizers. The electrodes showed different selectivity, limits of detection and the measurement range by using the same type of surfactant. The solution of the cationic surfactant Hyamine1622 has evinced the best response characteristics comparing to the all types of tested plasticizers. A deviation exists only in the membrane which contains the DBS. The response of this membrane in solution of Hyamine1622, CPC and CTAB is not suitable for further studies, and more over, the membrane is quite unstable and has short lifetime. However, in the DMIC solution and in the solutions of both anionic surfactants this membrane has showed satisfying response characteristics. The results revealed that the composition of a membrane directly affects its sensory properties of determination of anionic and cationic surfactants. In accordance with teacher preparation requirements, a unit plan for lecture called Soaps and detergents has been prepared. Lesson is designed as a combination of frontal and group work. The disciples have to meet the structure of soap and detergents, and specify their properties, which is also prove by performing experiments. After performing the experiment the disciples are expected to fill out worksheets and at the end of the lecture repeat the processed material
Arsenic in Eastern Croatia Water
No full textU radu je opisan arsen kao kemijski element te oblici u kojima se pojavljuje. Prikazani su najvažniji prirodni i antropogeni izvori arsena u okolišu te podzemnim i površinskim vodama (vodi za piće). Opisana je toksičnost arsena, promjene koje unos arsena uzrokuje u organizmu te zdravstveni rizici za izloženu populaciju. Navedene su i ukratko objašnjene metode određivanja arsena te metode uklanjanja arsena iz voda koje se koriste u vodoopskrbi. Detaljnije je obrađena problematika povećane koncentracije arsena u vodama istočne Hrvatske, što uključuje podatke o izmjerenim koncentracijama arsena u vodi za piće u pojedinim mjestima istočne Hrvatske, načine dospijevanja u vode te metode uklanjanja arsena iz voda.The paper presents chemical element arsenic and forms in which arsenic is present in the environment. It gives an overview of the most important natural and anthropogenic sources of arsenic in the environment and also in groundwater and surface waters (drinking water). It further presents toxicity of arsenic; changes that arsenic can cause when enter the organism and health risk for the exposed population. There is a brief overview of methods of arsenic detection and water purification that are most frequently used. There is also a detailed description of the problem with higher arsenic concentrations in Eastern Croatia, where the details of measured concentrations of arsenic in drinking water in some places of Eastern Croatia are listed. Also the ways of arsenic entering the water and methods of water purification are described