Repository of Department of Physics in Osijek
Not a member yet
172 research outputs found
Sort by
Physics of Human Voice
Get PDFLjudska vrsta jedina je tijekom svojeg postojanja uspjela razviti sposobnost govora što je uvelike
doprinijelo razvoju civilizacije. Razvojem govora ljudi su svoju mđusobnu koegzistenciju
olakšali i način sporazumijevanja podigli na efikasniju razinu. Ljudski glas sastavni je dio naše
svakodnevice, a njegov nastanak i fizikalna pozadina izuzetno je zanimljiva i predstavlja pitanje
na koje bismo mogli pronaći odgovor. U ovom je završnom radu uz pomoć poznavanja
elementarne anatomije čovjeka i akustike pojašnjeno kako nastaje ljudski glas i kakvi se sve
procesi pri tome odvijaju.Homo sapiens are the only species that has, during their existence, developed the ability to
communicate, which greatly contributed to the evolution of civilization. With communication,
human species have made their co-existence easier and the ways of mutual understanding has
been raised to a more effective level. Human voice is an integral part of an everyday life; hence
its genesis and physical background represents an interesting question, as well as the question
which needs to be answered adequately. This paper provides definitions on acoustics and
elementary anatomy of a human being, and it is centered on how human voice is created with
descriptions of inevitable processes which take place during the production of speech and
communication
Monte Carlo Study of the Atmospheric Penetration of High-Energy Cosmic Protons
Get PDFU ovom diplomskom radu istražena je prodornost visokoenergijskih kozmičkih protona u
atmosferu Zemlje. Pokriveno je energijsko područje od 10 GeV do 100 TeV, što je tipično
područje koje pokrivaju Čerenkovljevi teleskopi. Opisane su kozmičke zrake, Zemljina
atmosfera i programski paket CORSIKA, koji je korišten za Monte Carlo simulacije pljuskova
koje u atmosferi iniciraju kozmički protoni. Rezultati simulacija uspoređeni su s teorijskim
izračunom uz pomoć atmosferskog izotermnog modela. Određena je tipična visina prve
interakcije kozmičkog protona u atmosferi za navedeno energijsko područje. Također su
navedeni minimumi i maksimumi visina na kojima se događa prva interakcija proton-zrak.In this graduate thesis, the penetration of higy-energy cosmic protons in the Earth's
atmosphere was studied. Energy domain from 10 GeV up to 100 TeV was covered, which is
typical Cherenkov telescope detection domain. The cosmic rays, Earth's atmosphere and
CORSIKA software package, used for Monte Carlo simulation of showers which are
initiated by cosmic protons in the atmosphere, are described. The simulation results are
compared with theoretical calculation using the atmospheric isothermal model. Typical first
interaction hight in the atmosphere for mentioned energy domain was determined. The
minimum and maximum altitudes at which the first proton-air interaction occurs are also
found
Distribution of Ambient Dose Equivalent in the Donji Miholjac
Get PDFU teorijskom dijelu diplomskog rada opisani su temeljni pojmovi iz područja
radioekologije, a ti pojmovi uključuju definiciju zračenja, navođenje dozimetrijskih
veličina i uređaja za mjerenje. Nakon toga prikazana je metodologija mjerenja brzine
ambijentalnog doznog ekvivalenta na području Donjeg Miholjca koja su provedena
tijekom lipnja i srpnja 2017. godine. Cilj mjerenja bio je ispitivanje potencijalnog
utjecaja ozračenja na stanovništvo Donjeg Miholjca. Grafički prikaz dobivenih
rezultata prikazan je pomoću web GIS aplikacije koja na temelju zadanih parametara
identificira položajne podatke. Rezultati istraživanja pokazali su da meteorološki
parametri nemaju bitan utjecaj na brzinu ambijentalnog doznog ekvivalenta na
području Donjeg Miholjca.In the theoretical part of the thesis, the basic concepts in the field of radioecology are
described and these concepts include the definition of radiation, the naming of
dosimetric sizes and measuring devices. Thereafter, a methodology for measuring
the velocity of the ambient dose equivalent in the area of Donji Miholjac was
presented, which was carried out during June and July 2017. The aim of the
measurements was to examine the potential influence of irradiation on the population
of Donji Miholjac. A graphical representation of the results obtained is displayed
using a web GIS application that identifies placement data based on the default
parameters. The results of the research have shown that meteorological parameters
do not have a significant influence on the velocity of the ambient dose equivalent in
the area of Donji Miholjac
Fizika glazbe
Get PDFGlazba je umjetnost čiji je medij zvuk. Smatra se jednom od najstarijih umjetnosti koja se koristi
u različite svrhe – zabavljačke, religijske, komunikacijske itd. Ovaj se završni rad temelji na
proučavanju zvukova, tj. njihovim karakteristikama poput brzine, jakosti, kvalitete, boje i
frekvencije čije razumijevanje može produbiti znanje o glazbi. Kako je zvuk longitudinalni val,
bilo je bitno proučiti načine širenja valova te njihova svojstva. Veliku važnost u glazbi ima i
akustika, tj. područje fizike koje se bavi načinima dobivanja zvukova i zakonima njihovog širenja.
Glavni izvori zvukova jesu glazbeni instrumenti. U ovom je završnom radu napravljena glavna
podjela glazbenih instrumenata prema nastanku zvuka te su opisana svojstva instrumenata i načini
na koje istrumenti proizvode zvukove.Music is art whose media is sound. It is considered to be one of the oldest arts used for various
purposes - entertainments, religions, communication etc. This Bachelor thesis is based on the study
of sounds, ie their characteristics such as speed, strength, quality, color and frequency whose
understanding can deepen the knowledge of music. As sound is a longitudinal wave, it was also
important to study the ways how waves are spread and their properties. Of great importance in
music there is also acoustics, the field of physics dealing with the ways of making sounds and the
laws of their spread. The main sources of sounds are musical instruments. In this Bachelor thesis,
the main division of musical instruments has been made according to sound formation, the
characteristics of the instruments are described and it is presented the ways instruments are
producing sound
Parabolic Mirror
Get PDFZrcalom se koristimo svakodnevno, a da ustvari uopće ne pridajemo nikakvu važnost funkciji
zrcala. Zrcalo definiramo kao glatku površinu koja dobro reflektirati svjetlost. Dijelimo ih na ravna
i sferna zrcala. Postoje još i ne-sferna zrcala koje zapravo ubrajamo u sferna zrcala. Ne-sferna
zrcala su zrcala čija je ploha zaobljena, a neka od njih su elipsoidno, parabolično, valovito i slično.
Diplomski rad ima za cilj, uz glavne karakteristike ravnog i sfernog zrcala, opisati parabolično
zrcalo, matematičkim izvodom pokazati da se sve svjetlosne zrake kod paraboličnog zrcala
reflektiraju u žarištu zrcala, izraditi navedeno zrcalo i eksperimentalno potvrditi matematički
izvod. Također su navedeni eksperimenti koji pokazuju kako parabolično zrcalo može poslužiti
kao alternativni izvor energije. Na kraju je donesen zaključak i navedeni su razlozi zašto izrada
ovakvog zrcala postaje sve popularnija.We use mirrors daily but as a matter of fact we do not give any importance to the function of the
mirror. We define the mirror as a smooth surface that reflects the light. We divide mirrors into flat
and spherical. There are also non-spherical mirrors, they are actually part of spherical mirrors.
Non-spherical mirrors are mirrors whose surface is rounded and some of them are ellipsoidal,
parabolic, wavy and similar. The main goals of this thesis are describing the parabolic mirror with
the main features of the plane and spherical mirrors, by means of a mathematical statement that all
light beams reflect in the focus of the mirrors, create the mirror and experimentally confirm the
mathematical statement. Experiments that show how parabolic mirror can serve as an alternative
energy source are also mentioned. Conclusion and reason why making of this type of mirror is
becoming more and more popular are given at the end of this thesis
Farmakokinetičko modeliranje specifičnog kontrasta za jetru
Get PDFMeasurement of liver function after embolization is based on the application of
specific liver contrast agent which can be excreted through liver into the bile and
recording the whole process with magnetic resonance. By closing the branch of
the portal vein which enables food supply, we stimulate the growth of the second,
healthy, part of the liver. The analysis of MRI recordings consists of several
phases and gives curves that represent time-varying contrast concentrations in
blood and liver tissue. By using pharmacokinetic models for fitting the curves
we obtain parameters that describe the function of the liver; perfusion, contrast
uptake and extraction rate, volume of hepatocytes and sinusoidal cells.Mjerenje funkcije jetre nakon embolizacije temelji se na primjeni specifičnog
kontrasta za jetru, koji se putem jetre izlucuje u žuć te snimanjem cijelog procesa magnetskom rezonancom. Zatvaranjem jednog kraka portalne vene koja omogućuje dovod hranjivih sastojaka, potiče se rast drugog dijela jetre koji na sebe preuz-
ima funkciju djela zaraženog tumorom. Analiza snimaka magnetske rezonance, koja se sastoji od nekoliko faza, daje krivulje koje predstavljaju vremensku promjenu koncentracije kontrasta u krvi i tkivu jetre. Primjenom farmakokinetičkih
modela za opisivanje krivulja dobivamo parametre koji opisuju funkciju jetre; perfuziju, brzinu apsorpcije te izlučivanja kontrasta, volumen hepatocita te sinusoidalnih stanica
APPLICATION OF PHONES IN PHYSICAL EDUCATION
Get PDFU uvodnom dijelu diplomskog rada navedene su najčešće metode rada nastavnika u školama te nedostaci koji proizlaze iz takvog nastavnog procesa. Opisana je važnost pokusa i na koji način je integrirana u nastavi fizike. Navedena je primjena različite tehnologije u nastavi te razlozi zbog kojih postaju neizostavan dio nastavnog procesa. Središnji dio rada posvećen je objašnjavanju potrebe za uvođenjem mobitela i usporedbu s upotrebom laboratorijske opreme. Također, opisan je princip rada pojedinih komponenata mobitela te koju funkciju mogu obavljati u zadanim uvjetima. Metodički su obrađene dvije nastavne jedinice Slobodan pad i Zvuk, gdje se detaljno opisuje korištenje aplikacija za mjerenje fizikalnih veličina. Na kraju se navode načini primjene mobitela u raznim segmentima nastavnog procesa.The introductory part of the thesis deals with the most common methods of teacher work in schools and the disadvantages that arise from such teaching process. The importance of the experiment is described and how it is integrated into the teaching of physics. The application of different teaching technologies is mentioned and the reasons why they become an indispensable part of the teaching process. The central part of the paper is devoted to explaining the need for mobile phone introduction and comparison with the use of laboratory equipment. It also describes the principle of work of some cell phone components and which function can be performed under the given conditions. Two teaching units Free fall and Sound were handled methodically, where the use of applications for physical size measurement is described in detail. In the end, there are ways of using cell phones in various segments of the teaching process
Ultrasound and Applications
Get PDFUltrazvuk je mehanički val, odnosno zvuk frekvencije izvan spektra čujnosti ljudskog
uha, dakle iznad 20 000 Hz. U prirodi se ultrazvuk pojavljuje kao zvučni val, ali može se i
proizvesti ultrazvučnim generatorima, odnosno pretvaračima drugih oblika energije u energiju
ultrazvučnih valova. Tako se ultrazvuk može dobiti pomoću inverznog piezoelektričnog efekta,
te pomoću magnetostrikcije. Pri prolasku ultrazvuka kroz neki materijal dolazi do refleksije,
refrakcije, transmisije, difrakcije i apsorpcije ultrazvučnog vala. Ultrazvuk se primjenjuje u
mnogim tehničkim granama. Primjene su različite, mnogobrojne i od velikog značaja za
modernu tehnologiju.
U ovom završnom radu opisan je fenomen zvuka, te osnovna fizikalna svojstva zvuka. Rad
je posvećen ultrazvuku, izvorima ultrazvuka, te načinima rasprostiranja ultrazvučnih valova.
Također se bavi njegovim raznolikim primjenama u medicini, navigaciji, defektoskopiji itd.Ultrasound is a mechanical wave, sound frequencies beyond the range of audibility of the
human ear, above 20 000 Hz. In nature ultrasound appears as a sound wave, but it can also be
produced by ultrasonic generators. They convert other forms of energy into energy of ultrasound
waves. Ultrasound can be obtained by using the inverse piezoelectric effect and
magnetostriction. Passage of ultrasound through a material leads to reflection, refraction,
transmission, diffraction and absorption of ultrasonic waves. Ultrasound is used in many
technical fields. Applications of ultrasound are various, numerous and of great importance to
modern technology.
This bachelor's thesis describes the phenomenon of sound, and basic physical properties of
sound. This work is dedicated to ultrasound, ultrasound sources, and methods of propagation of
ultrasonic waves. It also deals with its various applications in medicine, navigation, defectoscopy, etc
Comparison of Several Methods for Measuring Radon Activity Concetration in Water
Get PDFU teorijskom dijelu diplomskog rada opisane su vrste radioaktivnog raspada, zakon
radioaktivnog raspada te radioaktivni raspadni nizovi. U radu je iskazana važnost te utjecaj
ionizirajućeg zračenja na čovjeka te u skladu s time su navedene i osnovne dozimetrijske veličine.
Prikazane su fizikalne i kemijske karakteristike radona i njegovih kratkoživućih potomaka te
načini prijenosa radona iz tla u vodu i zrak. Izneseni su zaključci istraživanja vezani za opasnosti
radona za zdravlje čovjeka.
U eksperimentalnom dijelu rada su opisani uređaji i metode kojima su izvršena mjerenja
koncentracije radona u vodi nakon čega su izneseni rezultati mjerenja. Na samom kraju
diplomskog rada je dan zaključak vezan za metode i rezultate mjerenja te njihovu korektnost.In theoretical part of this thesis the types of radioactivity, law of radioactivity and
radioactive decay chains are described. The importance and influence of ionizing radiation on
humans is stated in this thesis, together with basic dosimetry quantities and appropriate units.
Physical and chemical properties of radon and its short-lived progeny are described, as well as the
mechanism of radon transfer through the soil in water and air. Some conclusions on the influence
of radon and radon progeny on public health are presented.
In experimental part of this thesis devices and methods of radon measurements in water are
described and results are presented. Conclusions about used methods, obtained results and
discussion of the performances of all used methods are given at the end of this thesis
Commissioning of Megavoltage Photon Beam Lenear Accelerator Varian Clinic iX
Get PDFU ovome diplomskom radu opisana je priprema za kliničku uporabu novog medicinskog linearnog akceleratora
Varian Clinac iX, u Kliničkom bolničkom centru, u Osijeku. U radu su prezentirani svi dijelovi akceleratora i
objašnjen je njihov princip rada. Navedene su i detaljno objašnjene sve fizikalne veličine korištene u mjerenjima. U
eksperimentalnom dijelu rada prikazana su sva prihvatna dozimetrijska mjerenja koja se temelje na hrvatskom
Zakonu o radiološkoj i nuklearnoj sigurnosti, a obuhvaćaju testove sa fotonskim te elektronskim snopovima. Za
fotonske snopove mjerila se postotna dubinska doza, profili i output faktori za energije 6 MV, 6 MV FFF i 10 MV.
Za elektronske snopove mjerila se postotna dubinska doza te profili sa i bez aplikatora, za energija 6 MeV, 9 MeV,
12 MeV i 15 MeV. Svi su rezultati prikazani tablično i grafički.This master thesis describes commissioning of the new medical linear accelerator Varian Clinac iX at the Clinical
Hospital Center in Osijek. In this paper, all parts of the accelerator are presented and their working principles are
explained. All the physical units that are used in the measurements are explained in detail. All experimental
measurements based on Croatian Law of Radiological and Nuclear Safety, including photon and electron beam tests,
are shown in the experimental part of the paper. Percentual Depth Dose, Profiles and Output Factors are measured
for the photon beams, at the energy of 6 MV, 6 MV FFF and 10 MV. Also, Percentual Depth Dose and Profiles with
and without applicators are measured for the electron beams, at the energy of 6 MeV, 9 MeV, 12 MeV and 15 MeV.
All the results are presented graphical and in tables