Repository of Department of Physics in Osijek
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POSSIBLE SOLUTIONS TO THE FERMI PARADOX
No full textPotraga za životom u svemiru tema je od velike važnosti ne samo za potrebe astrobioloških istraživanja već i za čovječanstvo u cjelini. U ovom završnom radu dan je pregled prirode života i problema povezanih s njim, te pregled procesa i metoda astrobioloških istraživanja. Problem koji postavlja Fermijev paradoks iznesen je kroz ispitivanje Drakeove jednadžbe. Dano je nekoliko mogućih rješenja paradoksa uz zaključak da nepostojanje izvanzemaljskih civilizacija, iako se ne može definitivno potvrditi, predstavlja stvarnu mogućnost.Search for life in the universe is a subject of great importance not just for the purposes of astrobiological research but for humanity as a whole. In this bachelor thesis, an overview of the nature of life and the problems associated with it has been given, as well as an overview of the processes and methods of astrobiological investigations. The problem posed by the Fermi
paradox has been raised through the examination of the Drake equation. Several potential solutions to the paradox have been given with the conclusion that non-existence of extraterrestrial civilizations, although unable to be definitively proven, presents a genuine possibility
ANALYSIS OF DETERMINISTIC CHAOS BY USING NUMERICAL TOOLS IN PYTHON
No full textDeterministički je kaos teorija koja opisuje određene nelinearne sustave koji posjeduju izrazitu osjetljivost na početne uvjete. Takvi su sustavi deterministički u smislu da im je vremenska evolucija u potpunosti određena rješavanjem pripadne diferencijalne jedandžbe poznavanjem početnih uvjeta. Ponašanje ovakvih u načelu jednostavnih sustava može biti izrazito neprevidljivo i kaotično za dovoljno duge vremenske serije. U ovom ćemo diplomskom radu analizirati tri takva deterministička sustava i demonstrirati pod kojim će uvjetima doći do prijelaza u kaos. Najprije ćemo u teorijskoj podlozi uvesti notaciju i dati pregled
osnovnih svojstava, a zatim u drugom dijelu riješiti pripadne diferencijalne jednadžbe te varirati kontrolni parametar i početne uvjete. U toj ćemo analizi koristiti numeričke alate u Pythonu.Deterministic chaos is a theory which describes certain nonlinear dynamical systems that have a very sensitive dependence on initial conditions. Those system are deterministic in a sense that their time evolution is determined by solving corresponding differential equations and knowing the initial conditions. Behavior of this in principle simple systems can be very
chaotic if the time series are long enough. In this master’s thesis we will analyse three such deterministic systems and thus demonstrate the route to chaos. Firstly, we will introduce notation and give some basic properties in the theoretical introduction and after that we will solve corresponding differential equations and vary the control variable along with the initial conditions. In this analysis we will use numerical tools in Python
EFFECT OF ENERGY EFFICIENCY PROJECT ON INDOOR RADON CONCENTRATION LEVELS AT THE DEPT. OF PHYSICS AND THE DEPT. OF MATHEMATICS AT J. J. STROSSMAYER UNIVERSITY OF OSIJEK
No full textPoboljšanje energetske učinkovitosti postojećih građevina zadnjih je godina sve učestalije. Kako je konvekcija jedan od glavnih mehanizama gubitka topline u zgradama, samo izmjenom stare stolarije u novu PVC stolariju mogu se smanjiti strujanje zraka i
tako postići željeno smanjenje toplinskih gubitaka. Međutim, tim smanjenjem strujanja zraka olakšavamo nakupljanje radona u prostorijama unutar zgrade koji bi se inače ispustio u okolinu van zgrade. S obzirom da je radon drugi po redu (odmah nakon
pušenja) uzročnik karcinoma pluća u svijetu, takve neželjene pojave ne smiju se zanemariti. U ovom radu promatrane su prostorije jedne zgrade, Odjela za fiziku i Odjela za matematiku Sveučilišta J. J. Strossmayera u Osijeku u Republici Hrvatskoj, u kojima je
uočeno povećanje srednje koncentracije radona veće od trostrukog nakon postavljanja nove PVC stolarije u odnosu na prošle koncentracije kada je u pitanju bila stara drvena.Energy efficiency upgrades of existing buildings in recent years have become more frequent. As convection is one of the main mechanisms of heat loss in buildings, only by replacing old windows with new PVC ones, air flow can be reduced and thus the desired reduction in heat loss in a building achieved. However, that reduction of air flow facilitates indoor radon gas buildup which would otherwise vacate to the outdoor environment. Considering that radon is the second leading cause of lung cancer (second only to smoking) worldwide, such unwanted occurrences should not be ignored. In this paper, indoor radon concentration levels at the Dept. of Physics and the Dept. of Mathematics at J. J. Strossmayer University of Osijek, Republic of Croatia, are observed. The resulting average concentration levels after the installation of new PVC windows are more than tripled as opposed to levels with the old wooden ones before
Sunlight dependency on meteorological parameters
No full textMjerenja Sunčevog osvjetljenja izvršena su na lokaciji u privatnom vlasništvu nedaleko same meteorološke postaje Gradište što je omogućilo usporedbu vlastitih podataka s podacima koje je proslijedila meteorološka postaja. Podaci se ne mogu direktno usporediti jer meteorološka postaja ne mjeri Sunčevo osvjetljenje kao takvo, već mjeri koliko je dugo Sunce sjalo tokom određenog perioda dana te je li toga dana bilo više ili manje naoblake. Uzimajući u obzir te podatke oni se indirektno mogu povezati s vlastitim mjerenjima koja daju točnu količinu Sunčevog osvjetljenja i na taj način može se napraviti poveznica među ovim podacima.Measurments of sunlight illuminance were done at a private location in a close proximity of meteorological station Gradište, which made it possible to compare own data with the data from the meteorological station. The data can not be directly compared because the meteorological station does not measure sunlight as such, but it does measure how long
has the Sun shone during a certain period of the day and whether if there was more or less cloud cover that day. Taking this data into account, they can be indirectly linked to own measurements that give the exact amount of sunlight and thus a correlation can be made between own measurements and data provided by meteorological station
NUMERICAL ANALYSIS OF MOVEMENT OF 1D RANDOM WALK
No full textKod promatranja raznih fizičkih sustava i procesa s kojima se susrećemo i koji nas okružuju, često postoji težnja za korištenjem determinističkog načina razmatranja istih, za pretpostaviti je zato što je „lakše“ ili jednostavnije približiti si takve slučajeve. No, kako bi ostali dosljedni, treba prihvatiti kako u se u promatranjima stvarnih procesa i sustava zapravo radi o promatranju iznimno velikih
brojeva, često raznovrsnih čestica ili elemenata sustava, koji se na najmanjim razinama svaki ponašaju na određeni način. Kako bismo ih mogli promatrati i opisivati na način koji ima fizičkog smisla, nužno je koristiti se stohastičkim metodama i modelima. U ovome radu na primjeru nasumičnog hoda u jednoj dimenziji prikazana je upravo poveznica između determinističkog i stohastičkog pristupa razmatranjima.When observing various physical systems and processes we encounter regularly and which surround us, there is a tendency to use a deterministic approach to such observations, presumably because it is „easier“ or less complicated to draw near such cases. But, in order to remain consistent, we should accept that in observing realistic processes and systems, we come to
encompass extremely large numbers of often very diverse particles or system elements, all of which act in a specific way on the smallest scales. If we are to observe and describe such systems in a manner that has physical sense, it is necessary to apply stochastic methods and models. In this paper, an example of random walks in one dimension is used precisely to demonstrate the connection between the deterministic and stochastic approach
API TESTING IN POSTMAN
No full textU prvom dijelu diplomskog rada uvedeni su i pojašnjeni pojmovi API-ja, REST komunikacijskog protokola i JSON formata prijenosa podataka. Navedene su i objašnjene glavne HTTP metode za komunikaciju klijent-server kao i sastavni dijelovi zahtjeva i odgovora pri komunikaciji s API-jem. U drugom dijelu rada definiran je i opisan Postman kao glavni alat korišten u radu, njegovi elementi
sučelja te načini baratanja sa zahtjevima i pojedinim dijelovima odgovora. Cilj rada bio je opisati postupak testiranja API-ja u Postman alatu što je realizirano u završnom dijelu rada na konkretnom primjeru koristeći Spotify API.In the first part of the thesis, the concepts of API, REST communication protocol and JSON data transmission format were introduced and clarified. The main HTTP methods for client-server communication as well as the components of requests and responses when communicating with the API are listed and explained. In the second part of the paper, Postman is defined and described as the main tool used in the paper, as well as its interface elements and ways of dealing with requests
and individual parts of the answers. The aim of the paper was to describe the process of testing the API in the Postman tool, which was realized in the final part of the work on a specific example using the Spotify API
QUALITY CONTROL ON SPECT - CT DEVICE
No full textOvaj završni rad bavi se procesima kontrole kvalitete na SPECT – CT uređajima. Teorijski dio rada obrađuje opise postupaka kontrole kvalitete uređaja, te teorijski osvrt na najvažnije vrste testiranja koji se provode na dnevnoj, tjednoj, mjesečnoj, polugodišnjoj i godišnjoj bazi. Obavezni izvršitelji testova su medicinski fizičar za sve testove ili prvostupnik radiološke tehnologije ako su dnevni testovi u pitanju. Također, u radu se prikazuju i osnove zakonske regulative za kontrolu kvalitete uređaja koji emitiraju ionizirajuće zračenje.This final paper deals with quality control processes on SPECT - CT devices. The theoretical part of the work deals with descriptions of device quality control procedures, and a theoretical overview of the most important types of testing that are carried out on a daily, weekly, monthly, quarterly and annual basis. Mandatory test takers are a medical physicist or a bachelor's degree in medical radiology. Also, the paper presents the basics of legal regulations for quality control of devices that emit ionizing radiation
QUALITY CONTROL PROTOCOL (QC) FOR THE DETERMINATION OF RADON CONCENTRATION IN WATER ON A LIQUID SCINTILLATION COUNTER
No full textU ovom je diplomskom radu predstavljen protokol za kontrolu kvalitete za određivanje koncentracije radona u vodi na tekućinskom scintilacijskom brojaču. U početnom dijelu rada su ukratko objašnjeni pojmovi radioaktivnosti i zračenja, a zatim je objašnjeno što je to radon i kako utječe na nas. Nakon toga, opisana je metoda mjerenja koncentracije aktivnosti radona u vodi kao i način rada korištenih mjernih uređaja. U radu su istraženi utjecaji pojedinih dijelova mjernog procesa na kvalitetu rezultata mjerenja koncentracije aktivnosti radona u vodi: ovisnost temperature skladištenja uzorka, ovisnost amplituda mućkanja uzorka i koktela u viali, vrijeme mućkanja uzorka i koktela te na kraju ekstrakcija uzorka. Dobiveni rezultati ukazuju da temperatura skladištenja uzoraka utječe na rezultate mjerenja koncentracije radona odnosno uzorke je potrebno čuvati na nižim temperaturama. Nadalje, izmjerena koncentracija radona ne ovisi o amplitudi kojom se uzorak mućka, ali ovisi o trajanju mućkanja. Na kraju je utvrđeno
da nema potrebe provoditi višestruku ekstrakciju uzorka jer se većina radona već nakon prvog mućkanja zadrži u koktelu.This thesis presents a quality control protocol for determining the concentration of radon in water using a liquid scintillation counter. In the initial part of the paper, the concepts of radioactivity and radiation are briefly explained, and then it is explained what radon is and how it affects us. After that, the method of measuring the concentration of radon activity in water is described, as well as the method of operation of the used measuring devices. The paper studied the effects of individual parts of the measurement process on the quality of the results of measuring the concentration of radon activity in water: the dependence of the temperature of the sample storage, the dependence of the shaking amplitudes of the sample and the cocktail in the vial, the time of shaking the sample and the cocktail, and finally the extraction of the sample. The obtained results indicate that the storage temperature of the samples affects the results of the radon concentration measurement, that is, the samples need to be stored at lower temperatures. Furthermore, the measured radon concentration does not depend on the amplitude with which the sample is shaken, but it does depend on the duration of shaking. In the end, it was determined that there is no need to carry out multiple extractions of the sample because most of the radon remains in the cocktail after the first shaking
CRYSTAL LATTICE DEFECTS
No full textNa samome početku rada opisani su elementi strukture idealnoga kristala i najvažniji kristalografski pojmovi. Gibbsova slobodna energija u stanju termičke ravnoteže sustava poprima minimalnu vrijednost. Pokazano je da zbog toga stvarni kristali u stanju termičke ravnoteže na temperaturi iznad apsolutne nule uvijek sadrže određeni broj defekata. Ti defekti mogu biti statički i dinamički. Dinamički defekti uzrokovani su pobuđenjem kristala. Statički defekti nastaju pri konstrukciji kristala ili kasnijim izvanjskim djelovanjima. Statički se defekti klasificiraju s obzirom na broj dimenzija kroz koje se prostiru pa se tako razlikuju bezdimenzionalni ili točkasti, jednodimenzionalni ili linijski, dvodimenzionalni ili plošni te trodimenzionalni ili volumni defekti. S obzirom na to da su čest predmet proučavanja fizike čvrstoga stanja, u ovom je radu posebna pozornost dana točkastim i linijskim defektima. Također je određen broj Schottkyjevih i Frenkelovih defekata pri termičkoj ravnoteži na zadanoj temperaturi.At the very beginning of the paper, the elements of the ideal crystal structure and the most important crystallographic concepts are described. The Gibbs free energy in the thermal equilibrium state of the system must be at a minimum value. It has been shown that, therefore, real crystals in the state of thermal equilibrium at temperatures above absolute zero always contain a certain number of defects. They can be static and dynamic. Dynamic defects are caused by crystal excitation. Static defects
form during crystal construction or subsequent external actions. Static defects are classified according to the number of dimensions through which they extend, thus distinguishing between dimensionless or point, one-dimensional or linear, two-dimensional or planar, and three-dimensional or volume defects. Since they are a frequent subject of solid-state physics studies, in this paper special attention is given to point and line defects. The number of Schottky and Frenkel defects at
thermal equilibrium at a given temperature was also determined
ATTITUDES OF PARENTS OF PRIMARY SCHOOL STUDENTS TOWARDS DISTANCE LEARNING
No full textPredmet istraživanja ovog završnog rada su stavovi roditelja učenika osnovnih škola o nastavi na daljinu tijekom pandemije koronavirusa. Na početku je definiran pojam učenja na daljinu te su raspravljene njegove prednosti i nedostaci. U nastavku rada navedena su istraživačka pitanja i opisan je uzorak. Rezultati provedene ankete prezentirani su u posebnom poglavlju. Prema
rezultatima, roditelji uočavaju probleme vezane uz nastavu na daljinu i vjeruju da tradicionalna nastava u učionici ima pozitivniji utjecaj na njihovu djecu.The subject of this thesis is the attitudes of parents of primary school students towards distance learning during the COVID-19 pandemic. At the beginning, the term of distance learning is defined and its advantages and disadvantages are discussed. In the continuation of the paper, research questions are listed and the sample is described. The results of the conducted survey
are presented in a separate chapter. According to the results, parents notice problems related to distance education and believe that traditional teaching in a classroom has a more positive impact on their children