Repository of Department of Physics in Osijek
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The evolution of the early universe
Get PDFFizika ranog svemira nalazi se na granici astronomije i filozofije s obzirom da ne
postoji potpuna teorija koja ujedinjuje sve fundamentalne sile prirode u trenutku stvaranja.
Osim toga, ne postoji mogućnost povezivanja promatrane fizike ranog svemira
s trenutnim fizikalnim teorijama (tj. nije moguće izgraditi drugi svemir).
Većinu događaja u evoluciji svemira nakon vremena Planckove epohe (oko 10^−43
sekundi nakon Velikog praska) današnja fizika može objasniti. Medutim, događaji
prije tog trenutno su nedefinirani, a posebice ne razumijemo uzrok Velikog praska. U
najboljem slučaju, možemo naše napore usredočtiti na ispitivanje i definiranje onoga
što ne razumijemo u potpunosti.Physics of the early Universe is at the boundary of astronomy and philosophy since
there is no a complete theory that unifies all the fundamental forces at the begining.
Furthermore, there is no way of joining observation of early Universe physics to current
theories in physics (i.e. it’s not possible to build another Universe)
Our physics can explain most of the evolution of the Universe after the Planck
time (approximately 10^−43 seconds after the Big Bang). Though, events before this
time are still undefined and, in particular, we do not understand the origin of the Big
Ban. At best, we can focus our efforts on examining and defining what we do not fully
understand
Doppler effect and its applications
Get PDFChristian Doppler prvi je proučavao frekvencije zvuka te uočio da, ako nam se izvor
zvuka približava ili udaljava, ne čujemo istu frekvenciju koju je izvor odaslao. Uspio je
opisati i dokazati navedenu hipotezu javnim pokusom još u 19. st. Promatrajući iz perspektive
tog vremena nikada ne bismo mogli pretpostaviti da će to otkriće doživjeti tako raznoliku
primjenu i steći toliko veliku važnost u mnogim područjima fizike, kao što su astronomija,
medicina, navigacija i mnoga druga područja.
U ovom radu, uz kratak teorijski uvod i matematički prikaz same pojave Dopplerovog
efekta, bit će opisan način na koji se on primjenjuje u navedenim područjima.Christian Doppler was the first one who studied sound frequencies and noticed that, if
the source is coming towards us or going away from us, we do not hear the same frequency as
the source emitted. He managed to describe and demonstrate this hypothesis by public
experiment in the 19th century. From the perspective of that time, it could never be assumed
that this discovery would have a wide range of applications and gain great importance in
many areas of physics. The present application of Doppler effect is very broad and it is used
in astronomy, medicine, navigation and many other areas.
In this work, a short theoretical introduction and matematics from Doppler effect will
be explained, as well as its application in different areas
Optimization of dose and image quality in computed tomography
Get PDFCilj je ovog rada ukazivanje na odnos kvalitete dobivene slike kompjuterskom
tomografijom i doze koju pacijent primi prilikom skeniranja. Rad je popraćen i
eksperimentalnim dijelom kojim će se provjeriti iznijete činjenice o kvaliteti slike i dozi zračenja
koju pacijent primi.
Rad se ne bavi tehničkim specifikacijama CT uređaja ili detaljnim principom rada, no
neke osnove rada uređaja ipak su iznesene.
Rad je koncipiran tako da su prvih pet cjelina teorijski uvod u kojem se iznose činjenice i
podaci koji
su potrebni za razumijevanje eksperimentalnog dijela rada koji se nalazi u šestoj
cjelini. Nakon teorijskog i eksperimentalnog dijela slijedi zaključak rada. Također, u osmoj je
cjelini dodan prilog A koji govori o zaštiti pacijenata prilikom skeniranja C
T uređajem.The aim of this thesis is to point out the relationship between image quality obtained by computed tomography and the dose that patients receive during the scan. The thesis is accompanied by experimental part, which will outline the facts about image quality and the radiation dose that the patient receives.
This thesis does not deal with technical specifications of the CT scan, it only provides a basic description of its working principle. The thesis consists of a theoretical introduction that outlinies the facts and data necessary to understand the experimental part of the paper. The results of the research study conducted in this paper are also presented. Finally, Appendix A offers an insight into the protection of patients during CT scanning
PC as an Oscilloscope in teaching Physics
Get PDFDiplomski rad s temom Računalo kao osciloskop u nastavi fizike je podijeljen u tri dijela kojeg
čine analogni osciloskop, digitalni osciloskop i demonstracijske vježbe.
U prvom dijelu opisani su dijelovi analognog osciloskopa i njegov princip rada. Obuhvaćen je i
povijesni pregled razvoja osciloskopa te osnovna građa osciloskopa, kao i sustav za horizontalni
te vertikalni otklon.
U drugom dijelu je opisan digitalni osciloskop, računalo kao osciloskop i softver Visual
Analyzer.
Zadnji dio diplomskog rada čine demonstracijske vježbe, izvedena na računalu, pomoću
programa Visual Analyzer, koje se mogu primjenjivati u nastavi fizike. U svim
demonstracijskim vježbama je navedena potrebna aparatura, postupak izvođenja vježbe kao i
fizikalna podloga.My thesis on computer oscilloscopes is divided into three main parts. The analogue oscilloscope,the digital oscilloscope and experiments.
The first part includes descriptions of the parts and work principle of the analogue oscilloscope.
It also includes a overview of the history and basic structure of the analogue oscilloscope, as well as a description of systems for horizontal and vertical deflection.
In the next part I describe the digital oscilloscope, PC oscilloscope and the software Visual Analyzer.
The last part of my thesis contains experiments, used in teaching physics, performed on a PC oscilloscope. In all of the presented experiments there is a description of the necessary equipment, the way in which they were performed and the foundation each experiment has in physics
Michelson’s interferometer
Get PDFMichelsonov interferometar je uređaj koji razdvaja zraku svjetlosti na dvije koje imaju
odvojene putanje te se ponovo sastaju na detektoru. Inteferometar, kojeg je konstruirao
Michelson, se sastoji od koherentnog izvora svjetlosti (natrijeve lučice, a danas lasera), djelitelja
snopa, dva zrcala (od kojih je jedno pomično) i detektora (teleskopa ili u našem slučaju bijelog
zastora). Michelsonov interferometar se koristi za određivanje malog pomaka predmeta, mjerenje
indeksa loma optičkog sredstva i za detekciju gravitacijskih valova. Također, možemo ga
koristiti i za podešavanje drugih optičkih uređaja.The Michelson interferometer is a device that separates a beam of light into two separate tracks which meet again on the detector. The Inteferometer, constructed by the Michelson, consists of a coherent light source (sodium harbor or laser nowadays), a beam splitter, two
mirrors (one of which is movable) and a detector (a telescope or in this case a white curtain). The Michelson interferometer is used to determine small displacements of objects, to measure the refractive index of the optical device and to detect gravitational waves. Also, we can use it to set up other optical devices
Analysis of Osijek high school students' attitude towards education in physics and informatics
Get PDFU diplomskom radu prezentirani su rezultati ankete čiji je cilj bio ispitati stavove srednjoškolskih učenika o nastavi fizike i informatike. U ispitivanju je sudjelovalo 1049 učenika sedam osječkih srednjih škola. Dobiveni odgovori prezentirani su po spolu, razredu i školi, a u analizi podataka korištene su metode deskriptivne i inferencijalne statistike. Istraživanjem se nastojalo utvrditi koliko je nastava fizike i informatike zanimljiva učenicima, kako su opremljeni kabineti, koliko su učenici zadovoljni udžbenicima i načinom predavanja svojih profesora te s kojom lakoćom usvajaju nove pojmove iz navedenih nastavnih predmeta. Rezultati analize pokazuju da postoji potreba da se nastava iz oba predmeta dodatno približi srednjoškolskim učenicima te da se na taj način poveća njihov interes za fiziku i informatiku. Istraživanje je također otkrilo da u praktički svim analiziranim aspektima srednjoškolski učenici statistički značajno pozitivnije percipiraju nastavu informatike, nego nastavu fizike.This master thesis presents the results of the survey that was conducted in order to determine the attitudes of high school students towards education in physics and informatics. The total number of Osijek high school students which participated in the research was 1049. The results are presented in tables, differentiated by gender, class and school. The collected data were analysed by using descriptive and inferential statistical methods. The survey tried to determine how interesting the physics and informatics education is for the students, how satisfied they are with students’ books, the way of professors’ teaching, and current state of equipment, and how easily they acquire new terms of the given subjects. The results of the analysis show that there is a need to make the education more students friendly in order to maximize their interest in physics and informatics. The survey also revealed that, in almost every aspect analysed, high school students perceive informatics education more positive than physics
Radon in houses in Medimurje county
Get PDFU teorijskom dijelu diplomskog rada opisani su tipovi radioaktivnosti, zakon radioaktivnog raspada, a navedene su i vrste i izvori zračenja. Zatim su definirane osnovne dozimetrijske
veličine i njihove mjerne jedinice.
Prikazane su fizikalno-kemijske karakteristike radona i
njegovih kratkoživućih potomaka. Opisan je način na koji radon ulazi u kuće te postupci prevencije njegova ulaska kao i postupci smanjenja povišene koncentracije radona u kućama.
Objašnjen je štetan utjecaj radona na zdravlje čovjeka kao razlog zbog kojeg se i vrši istraživanje koncentracije radona u
kućama.
U eksperimentalnom dijelu rada objašnjena je metoda mjerenja radona pomoću detektora nuklearnih tragova. Detaljno je opisan način izrade, postavljanja i prikupljanja detektora, kao i
sama obrada rezultata mjerenja. Dobiveni podaci predstavljeni su tablično i grafički izradom dva zemljovida radonske koncentracije: po administrativnim jedinicama (Međimurska županija) te
mrežnim pristupom. Izmjerene koncentracije rad
ona u kućama su bile u intervalu od 11 do 528 Bq m^{-3}
, a srednji ravnotežni faktor iznosi 0,55.
Srednji godišnji efektivni dozni ekvivalent za radon i
njegove kratkoživuće potomke, prema korištenom ICRP 65 modelu,
za stanovnike Međimurske županije iznosi 2,09 mSv.In the theoretical part of this bachelor thesis, the types of radioactivity, law of radioactivity as well as the meaning of radioactivity in general are described. The basic dosimetric quantities and its units are defined. After that, the physical and chemical properties of radon and its short-lived progeny are introduced. The sources of radon are specified and the mechanisms of entering the houses as well as the importance of protecting and decreasing radon levels in houses are emphasized. The impact of radon issue on public health and related experimental research are
commented.The method of radon measurement by nuclear track
etched detectors is described in experimental part of this thesis
. The way of producing, setting up and collecting of detectors as
well as the way of their analysis is briefly described. The obtained data are presented in tabular and
graphical ways. Two indoor radon maps are produced: one using administrative borders of Međimurje county
and the other using grid cell approach.
Indoor radon concentrations were in range from 11 to 528 Bq m^{-3}. The averaged equilibrium factor was 0.55 . The population of the
Međimurje county receive the annual effective dose equivalent due to
radon and its short-lived progeny of 2.09 mSv
in average
Cloud Chamber
Get PDFDiplomski rad s temom Maglena komora podijeljen je u tri dijela. U uvodu je naglašena
njezina vaţnost u fizici. Nakon toga su opisani različiti detektori zračenja i njihove
karakteristike. Kao teorijski dio rada opisana je originalna maglena komora koju je
izradio C. T.
L. Wilson te sva otkrića u znanosti koja su uslijedila. Nakon toga je, kao praktični dio, opisan
postupak dizajniranja maglene komore te je predočen krajnji proizvod. Na kraju su prezentirani
rezultati eksperimenata pomoću napravljene maglene komore. Kao dodatak je opisana primjena
maglene komore u nastavi fizike.Master thesis with the topic Cloud chamber is divided into three parts. The introduction highlighted its importance in physics. Further in the paper, various, radiation detectors and their characteristics, are described.
As a theoretical part of the thesis, the original cloud chamber created by C.T.L. Wilson and all the discoveries in science that followed, are described. After that, as a practical part of the thesis,
the process of designing a cloud chamber is described and its final product is presented. Finally, the paper presents the results
of experiments which have been made with that cloud
chamber. Application of cloud chamber in teaching physics is
described , as an addition
ICT competence of teachers in primary schools in the Eastern and Central Croatia
Get PDFTema diplomskog rada prezentira kompetencije učitelja informatike iz područja informacijsko komunikacijske tehnologije (u daljnjem tekstu IKT) u nastavi informatike osnovnih škola Istočne i Središnje Hrvatske. U prvom teorijskom dijelu obrađeni su osnovni pojmovi koji upućuju na obaveznu primjenu IKT-a u području formalnog obrazovanja.
Drugi dio diplomskog rada prikazuje rezultate ankete: IKT kompetencije učitelja u osnovnim školama. Anketa u obliku upitnika na papiru provedena je u okviru održavanja stručnih skupova Županijskih stručnih vijeća učitelja informatike. Anketirano je 232 učitelja informatike. Rezultati istraživanja prikazani su tablično a pri izračunu korišteni su osnovni pokazatelji deskriptivne i inferencijalne statistike.The Diploma work thesis presents the competence of teachers in the field of computer information and communication technologies (hereinafter ICT) in informatics teaching in primary schools, in the Eastern and Central Croatia. The first theoretical part deals with the basic terms that refer to the mandatory application of ICT in the field of formal education. The second part deals with the survey results: ICT competence of teachers in primary schools.
The survey in the form of a fill in questionnaire has been implemented within the framework of a series of professional meetings of the County based councils of informatics teachers. The survey involved 232 teachers of informatics. The research results have been displayed in the table, whereas the calculation was made by use of the basic indicators of descriptive and inferential statistics
ANALISIS OF CROATIAN UNIVERSITIES STUDENTS ATTITUDES TOWARDS ONLINE LEARNING
Get PDFPredmet istraživanja ovog diplomskog rada je online učenje u hrvatskom visokom obrazovanju sa stajališta studenata. U uvodu je objašnjena potreba za online oblikom nastave i njegov proces prilagodbe pedagoškoj paradigmi. Nakon toga prikazan je povijesni razvoj učenja na daljinu, od korespondentnog do e-učenja. Zatim su objašnjeni pojmovi učenja na daljinu, e-učenje i online učenja uz pregled njihovih definicija. Na kraju su prezentirani rezultati istraživanja online učenja provedenog među hrvatskim studentima. Cilj istraživanja je bio utvrditi percepciju studenata i koliko je online učenje prihvaćeno na hrvatskim sveučilištima.The subject of this master thesis is online learning in Croatian higher education from students' perspective. The need for online form of education as well as its process of adjustment to the pedagogical paradigm are briefly explained in the introduction. Further in the paper, history of distance education, from basic correspondent learning to e-learning, is presented. It is followed by explanation of concepts of distance education, e-learning, and online learning with a review of their definitions. Finally, the paper presents the results of research on online learning conducted among Croatian students. The aim of the survey was to determine students’ perceptions and the extent to which online learning has been adopted by Croatian universities