Search

Predmet istraživanja ovoga rada je granulometrijska analiza laserskom difrakcijom. Cilj istraživanja je utvrditi postupak pripreme uzorka te uvjeta mjerenja laserskim difraktometrom na primjeru analize donjokrednog paleotla iz kamenoloma Kanfanar u Istri. U teoretskom dijelu rada opisana je metoda laserske difrakcije. Također je prikazana važnost rezultata granulometrijske analize geoloških materijala u različitim geološkim disciplinama. Praktični dio rada sastojao se od niza različitih priprema uzorka i granulometrijskih analiza s različitim postavkama mjerenja. Laserski granulometar korišten pri izradi ovoga rada je Mastersizer 3000 nizozemsko-britanske tvrtke Malvern Panalytical. Na temelju rezultata opetovanih mjerenja analiziranog uzorka poznatog mineralnog i kemijskog sastava, razrađen je standardni operativni postupak (SOP) pripreme uzoraka i analize laserskom difrakcijom. Izrađen SOP je primijenjen i na ostalim uzorcima iz profila paleotla lokaliteta Kanfanar. Rezultati su prikazani tablično (kvantili i volumni udjeli pojedinih granulometrijskih frakcija) te grafički (kumulativne granulometrijske krivulje). Analizirani uzorci su klasificirani sa stanovišta sedimentologije, pedologije, hidrogeologije i inženjerske geologije. Ovaj rad izrađen je u sklopu HRZZ projekta IP-2019-04-8054 WIANLab - Zapadnoistarska antiklinala kao idealni prirodni laboratorij za proučavanje regionalnih diskordancija u karbonatnim stijenama., The subject of this thesis is the grain size analysis by laser diffraction. The aim of the research was to develop the procedure for sample preparation and measurement settings of laser diffractometer using samples of Lower Cretaceous paleosol from the Kanfanar quarry in Istria. The theoretical part of the thesis describes the laser diffraction method. It also presents the importance of grain size data of geological materials in different geological disciplines. The practical part of the work consisted of a series of different sample preparations and grain size analyzes using different measurement settings. The laser diffractometer used in this study is the Mastersizer 3000 from the Dutch-British company Malvern Panalytical. Based on the results of repeated measurements of the analyzed sample with known mineral and chemical composition, a standard operating procedure (SOP) for sample preparation and its analysis by laser diffraction was developed. The developed SOP was applied to other samples from the paleosol profile of the Kanfanar site. The results are presented in tables as quantiles and as volume percentages of each grain size fraction, and graphically as cumulative granulometric curves. The analyzed samples are classified from the standpoint of sedimentology, pedology, hydrogeology and engineering geology. This work was carried out within the framework of the project IP-2019-04-8054 of the Croatian Science Foundation WIANLab - Western Istrian Anticline as an ideal natural laboratory for the study of regional unconformities in carbonate rocks.

Cilj ovog rada bio je sagledati princip rada ultrazvuka te ispitati utjecaj amplitude ultrazvuka na veliĉinu kristala boraksa dobivenih postupkom kontroliranog hlaĊenja u kristalizatoru s miješanjem. U prvom dijelu istraživanja provedena je šaržna kristalizacija u reaktoru s miješanjem iz otopine zasićene pri temperaturi od 30 °C i hlaĊene brzinom od 6 ° C h -1 . Pri tome je praćena promjena koncentracije otopine kako bi se utvrdio poĉetak nukleacije i promjena koncentracije uslijed rasta kristala, a po završetku procesa izvršeno je prosijavanje i granulometrijska analiza produkta. U drugom dijelu radu sagledavan je utjecaj amplitude ultrazvuka na tri izdvojene klase prethodno dobivenog produkta šaržne kristalizacije uz miješanje. Pri ovim ispitivanjima su klase kristala srednje veliĉine od 45, 170 i 375 m, ultrazvuĉno su suspendirane u otopini acetona zasićenoj i termostatiranoj pri 25 °C. Amplitude ultrazvuka iznosile su 20, 30 i 40 %. Nakon djelovanja ultrazvuka u trajanju od 10, 20 i 30 min granulometrijska svojstva kristala analizirana su metodom laserske difrakcije. Istodobno, uz mjerenje veliĉine kristala odreĊivana je elektriĉna vodljivost otopine, , kako bi se sagledale koncentracijske promjene unutar otopine. Rezultati rada ukazali su da niti jedna od izdvojenih klasa kristala nije znaĉajno promijenila svoju veliĉinu tijekom procesnog vremena pri ispitivanim amplitudama ultrazvuka. TakoĊer ni vodljivost otopine nije se promijenila, zbog ĉega se može zakljuĉiti da navedene amplitude neće uzrokovati lom niti otapanje kristala boraksa te ih se može koristiti pri ispitivanju utjecaja ultrazvuka na kinetiku kristalizacije boraksa. The purpose of this study was to observe the ultrasound working principle and to examine the influence of ultrasonic amplitude on the size of borax crystal obtained by the controlled cooling in the batch stirred crystallizer. In the first part of the study, batch crystallization was carried out in a stirred reactor from a solution saturated at 30 ° C and cooled at 6 ° C h -1 . Concentration change of the mother liquor over process time was measured in order to determine the onset of nucleation and the change in the concentration due to crystal growth. Upon the completion of the process, sieving and granulometric analysis of the product was done. In the second part of the work, the effect of ultrasound amplitude on three classes of crystals obtained in a batch stirred reactor was examined. The classes of crystals of average size 45, 170 and 375 m were ultrasonically suspended in a solution of acetone saturated and thermostated at 25 ° C. Ultrasound amplitude was 20, 30 and 40%. After 10, 20 and 30 min of ultrasonic treatment, the granulometric properties of the crystal were analysed by laser diffraction method. At the same time, with the measurement of the crystal size, the electrical conductivity of the solution, , was measured in order to monitor concentration change within the solution. The results of the study showed negligible change in size of examined crystal classes over process time at the applied ultrasound amplitudes. Also, the conductivity of the solution has not changed, which indicated that applied amplitude will not cause breakage or dissolution of the borax crystals and can be used in the further study of influence of ultrasound on the crystallization kinetics of borax.

Klasičnim sijanjem praškastih materijala često dolazi do pojave aglomerata koji onemogućavaju ravnomjeran i potpun prolaz čestica kroz očice sita. U ovom završnom radu provedena je granulometrijska analiza uzoraka sa i bez primjene ultrazvuka visokog intenziteta i laserska analiza raspodjele veličine čestica pri čemu su korišteni uzorci smeđeg šećera i fruktoze, prethodno samljeveni na 6000 i 12000 o/min. Korištena su sita promjera očica: 355, 280, 180, 100, 56 i 20 μm. Uzorci su prosijani pri amplitudama trešnje od 1.0 i 2.0 mm u vremenskom intervalu od 3 sekunde, trajanju od 5 minuta sa i bez primjene ultrazvuka visokog intenziteta uz amplitudu od 80%. Rezultati granulometrijske analize prikazani su kao ovisnost relativne učestalosti o veličini otvora očica sita pri primijenjenoj amplitudi sijanja. Iz rezultata je vidljivo da primjena ultrazvuka poboljšala ujednačenost raspodjele veličine čestica. Najbolji rezultati postignuti su primjenom kombinacije ultrazvuka i amplitude trešnje od 2 mm. Agglomeration phenomenon which prevents continuous passage of powder particles through sieve is the biggest problem of classical sieving. In this undergraduate thesis, granulometric analysis of samples with and without application of high intensity ultrasound and laser particle size distribution were conducted, using samples of brown sugar and fructose previously milled at 6000 and 12000 rpm. Sieve opening sizes were 355, 280, 180, 100, 56 and 20 μm. The samples were sieved at the amplitude of 1.0 and 2.0 mm in intervals of 3 seconds, during 5 minutes, with and without application of high intensity ultrasound (amplitude of 80%). Results of sieving analysis are presented as a step-like frequency distribution curve at a determined amplitude of ultrasound. It is shown that the high intensity ultrasound enhances the effect of sieving. The best results were achieved with a combination of ultrasound and 2.0 mm amplitude.

Veličina i raspodjela veličina čestica značajni su u mnogim postupcima farmaceutske industrije, kao što su tabletiranje i granuliranje, budući da o veličini čestica i njihovom obliku ovisi brzina otpuštanja djelatne tvari, a time i bioraspoloživost u organizmu. Cilj ovog rada bio je usporediti metode laserske difrakcije i analize slike pri mjerenju raspodjele veličina čestica praškastog uzorka. Istraživanje je provedeno na 24 uzorka dobivenih usitnjavanjem farmaceutske djelatne tvari dronedaron-hidroklorida. Uspoređene su vrijednosti kvantila dobivene pomoću obje metode. Na temelju raspodjela veličina čestica dobivenih metodama laserske difrakcije i analize slike može se zaključiti da postoji značajno odstupanje u dobivenim raspodjelama. Najznačajnije odstupanje dobiveno je u području manjih čestica gdje se očituje nedostatak metode laserske difrakcije. Zbog nesferičnih čestica analiziranih uzoraka, metoda analize slike daje relevantnije podatke o raspodjeli veličina čestica. Particle size and particle size distribution are significant in many pharmaceutical industry processes such as tableting and granulation, since particle size and shape have significant effect on drug release profile and thus bioavailability in the body. The aim of this research was to compare the methods of laser diffraction and image analysis when measuring the particle size distribution of the powder samples. The study was conducted on 24 samples obtained by micronization of the pharmaceutical active ingredient, dronedarone hydrochloride. The values of quantiles obtained by both methods are compared. Based on the particle size distribution obtained by laser diffraction method and image analysis, it can be concluded that there is a significant difference in distribution results. The most significant deviation was obtained for small particles where the disadvantage of the laser diffraction method is evident. Because of non-spherical particles of analyzed samples, the image analysis method gives more relevant data on the particle size distribution.

Cilj ovog diplomskog rada bio je istražiti granulometrijske, mineraloške te morfološke značajke recentnih sedimenata Plitvičkih jezera. Analizirani su uzorci iz jezgri sedimenata s četiri lokaliteta u jezeru Prošće, tri lokaliteta u jezeru Kozjak, te s jednog lokaliteta u Matici, Gradinskom jezeru i jezeru Kaluđerovac. Za određivanje granulometrijskih značajki sedimenta korištena je metoda laserske difrakcije (LD), mineraloški sastav određen je rendgenskom difrakcijom na prahu (XRD), a morfološke značajke sedimenta istražene su primjenom pretražne elektronske mikroskopije s visokim razlučivanjem (FE-SEM). Prema klasifikacijskom modelu koji je predložio Shepard (1954) sedimenti Gradinskog jezera svrstani su u grupu pijeska, sedimenti jezera Kozjak u grupu silta, a sedimenti Matice i Prošća u grupu pjeskovitog silta. U karbonatnom precipitatu iz Matice i mladoj sedri iz jezera Galovac jedina dominantna mineralna faza je visoko kristalizirani kalcit, uz koji se pojavljuju male količine dolomita. Sedimenti jezera Kozjak sadrže približno 95 % kalcita, te manje količine dolomita i kvarca. Najzastupljenije čestice kalcita u recentnim sedimentima imaju značajke mezokristalnih struktura što ukazuje na procese formiranja kalcitne mineralne faze iz vodenog sustava. U Matici je u kalcitnim mineralnim prevlakama uočena pojava cijanobakterija, što ukazuje na njihov značaj u biološki induciranim procesima formiranja kalcita., This thesis provides granulometrical and mineralogical properties of recent sediments from the Plitvice Lakes. Sediment cores were collected at four stations from the Lake Prošće, three stations from the Lake Kozjak and one station from the Matica, the Gradinsko Lake and the Lake Kaluđerovac. Sediment samples were granulometrically characterized by laser diffraction (LD), identification of mineral composition was performed by X-ray powder diffraction (XRD) and morphological properties of particles were analyzed by field emission scanning electron microscopy (FE-SEM). Considering the ratio of different grain size fraction (Shepard, 1954), sediment from the Gradinsko lake was classified as sand, sediment from the Kozjak Lake was classified as silt, while the sediments from the Matica and the Prošće Lake were classified as sandy-silt. The dominant mineral phase in tufa from the Matica and the Galovac Lake was highly crystallized calcite with partial appearance of dolomite. The recent sediments from the Kozjak Lake consist of approximately 95 % calcite and a small amount of dolomite and quartz. The most common morphology of calcite particles found in sediment was mesocrystal shape, which exemplifies the role of biologically induced inorganic precipitation processes in their formation. The appearance of cyanobacteria in the precipitates of the Matica indicated the significance of cyanobacteria in formation of calcite solids.

Granulometrijski sastav tla (GST) jedan je od najvažnijih parametara fizikalnih značajki tla koji ima utjecaj na gotovo sva fizikalna i brojna kemijska svojstva tla. Pokazatelj je masenog udjela pojedinih čestica u tlu (pijeska, praha i gline) koje su klasificirane prema veličini u frakciju sitnice (čestice manje od 2 mm u promjeru). Cilj ovog rada bio je utvrditi da li postoje razlike u rezultatima koji se dobivaju prilikom određivanja GST pomoću tri različite metode. Korištena je klasična pipet-metoda s Na-pirofosfatom prema Pedološkom priručniku (KP), normirana pipet-metoda (ISO 11277) (NP) te metoda s laserskim difraktometrom SALD 2300 (LD). Analizirano je 15 uzoraka površinskih i potpovršinskih slojeva tla teksturnih oznaka: pjeskovita ilovača (PI) (pet uzoraka), praškasta ilovača (PrI) (pet uzoraka) i praškasto glinasta ilovača (PrGI) (pet uzoraka). Dobiveni rezultati istraživanja su testirani neparametrijskom metodom, Friedmanovom analizom varijance (X2) i Wilcoxonovim testom. Statistička analiza je pokazala da su razlike između tri metode statistički značajne za sve analizirane frakcije (krupni pijesak, krupni i sitni prah, glina) osim za frakciju sitnog pijeska. Na temelju dobivenih udjela pijeska, praha i gline, određena je i teskturna oznaka analiziranih uzoraka tla pomoću teksturnog trokuta (FAO 2006). Usporedbom rezultata na teksturnom trokutu u uzorcima koji sadrže 15% gline i više uočeno je značajno odstupanje lasera u odnosu na pipet metode. Obzirom da tri istraživane metode za analizu GST daju rezultate koji se statistički značajno razlikuju, potrebna su daljnja istraživanja tj. usporedbe metoda i to koristeći veliki broj uzoraka, te na tlima različite teksture i različitih sadržaja organske tvari. Posebno se to odnosi na lasersku difrakciju, kao noviju metodu koja će se u budućnosti sve više koristiti jer zahtijeva malu količinu uzoraka i kratko vrijeme za analizu. Particle-size distribution is one of the most fundamental physical properties of soil. It is a list of values that defines the relative amount, typically by mass, of particles present according to size. The objective of this study is to determine the differences in the results obtained by the determination of soil praticle-size distribution (PSD) with three different methods. The old classic method with Na-pyrophosphate, pipette method according to the ISO 11277 and laser diffractometer (SALD 2300) were used. A comparison between methods was carried out for 15 surface and subsurface soil samples from continental Croatia whose textural classes are sandy loam (SL) (five samples), silt loam (SiL) (five samples) and silty clay loam (SiCL) (five samples). The results of this research are tested with non-parametric method – Friedman's analysis of variance (X2) and with Wilcoxson's test. The differences between three tested methods are statistically significant for all soil fractions except for the fine sand. In textural interpretation, using textural triangle, differences between methods are also visible. In samples that contain 15 % or more clay, deviation between the laser method and the two pipette methods is observed. Considering that this three used methods do not give the same results, further researches are needed using a large number of samples and in the soils of different textures and different content of organic matter. This is especially true for the laser diffraction method, which is expected to be even more used in the future because it requires a small amount of samples and a short time for analysis.

U ovom diplomskom radu opisuju se i razmatraju sedimentološke, mineraloške i morfološke značajke recentnih sedimenata mljetskih jezera (Jadransko more, Hrvatska). Granulometrijske značajke sedimenata analizirane su primjenom laserske difrakcije (LD). Mineralni sastav i morfološke značajke sedimentnih čestica ispitani su rendgenskom digrakcijom na prahu (XRD), odnosno pretražnim elektronskim mikroskopom s visokom rezolucijom (FE-SEM). Potvrđeno je da u mineralnom sastavu sedimenta Malog jezera prevladavaju aragonitne igličaste čestice. Prisutnost aragonita u Velikom jezeru je manja nego u Malom jezeru, dok je u površinskom sedimentu otvorenog mora njegov sadržaj zanemariv. U Malom jezeru po prvi je puta uočena pojava autigenog framboidalnog pirita u dubljim segmentima jezgre sedimenta što ukazuje na periode anoksije u njegovim dubljim dijelovima., This master thesis describes and discuses the sedimentological, mineralogical and morphological properties of recent sediments from the Mljet Lakes (Adriatic Sea, Croatia). Granulometric characteristics of sediments were analyzed by laser diffraction (LD). The mineral composition and morphological properties of sediment particles were examined by X-ray diffraction (XRD) and field emission electron microscopy (FE-SEM), respectively. It was confirmed that aragonite in the form of needle-like particles is the dominant mineral phase in the sediment of the Malo Jezero lake. The presence of aragonite in sediment of Veliko Jezero lake was diminished, while only a negligible amount of aragonite was found in the surface sediments from the open sea. The existence of authigenic framboidal pyrite was determined for the first time in deeper segments of the core sediment, indicating periods of anoxia in the deeper parts of the Malo Jezero lake.