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Ultrasound
No full textU prvom dijelu diplomskog rada opisala sam povijesni razvoj ideja o zvuku, valne pojave
u prirodi i pojave koje prate zvučne valove, granice čujnosti ljudskog uha te definirala ultrazvuk.
U drugom dijelu opisujem rezultate eksperimenata u kojima se određuje valna duljina ultrazvuka
u tekućinama i računa njegova brzina iz optički projicirane slike te kako brzina ultrazvuka ovisi o
temperaturi tekućine na primjeru za destiliranu vodu. Nadalje, osim eksperimentalnog dijela koji
sam odrađivala u praktikumu Odjela za fiziku, izradila sam ultrazvučni detektor šišmiša koji
detektira njihovo glasanje i na taj se način može odrediti prisutnost određene vrste šišmiša na
promatranoj lokaciji. U posljednjem dijelu dajem zaključak o izvedenim pokusima te povezujem
dobivene rezultate s fizikalnom teorijom o ultrazvuku.In the first part of this master thesis, the development of the basic concept of the sound
through the history of science as well as the wave and sound phenomena in nature were described,
frequency range of a human ear was determined, and ultrasound was explained. In the
experimental part the several experiments were described. Firstly, the wave length of sound in
some fluids was determined and speed of sound from a projected picture was calculated. Secondly,
dependence of the speed of sound on the temperature of a fluid (water) was investigated. Finally,
bat detector was constructed, and detailed instructions for that were presented. Bat detector is a
device which detects if bats are present at a certain location and works on frequencies of
ultrasound. The application of constructed bat detector was presented at 18th International Bat
Night in Osijek ZOO. In conclusion, the obtained results from the experiments were discussed and
some additional application of ultrasound in our lives were described
Traffic collisions
Get PDFNa početku diplomskog rada istaknuta je uloga fizike i njezine praktične primjene u analizi
sudara, nakon čega je ukratko prikazan razvoj mehanike kroz povijest. U trećem poglavlju
opisane su temeljne fizikalne veličine i zakoni bez kojih ne bi bilo moguće analizirati sudar,
vrste sudara, te osnovne zakonitosti koje se pri njima javljaju, što je detaljnije razrađeno u
slijedećem poglavlju. U petom poglavlju povezane su fizikalne veličine razmotrene ranije sa
konkretnom primjenom, te jednadžbe koje se temeljem znanja iz prethodnih poglavlja
primjenjuju u analizi sudara. U šestom poglavlju dan je primjer analize stvarnog sudara sa
odgovorima na konkretna, često postavljena pitanja relevantna u istom.At the beginning of the thesis, an emphasized was put on the role of physics and its practical
application in the collision analysis, followed by a brief illustration of the history of
mechanics. In the third chapter, basic physical dimensions and laws that enable analysis of a
collision are described, as well as the types of collision and fundamental principles that
manifest themselves during collisions, which is further clarified in the next chapter. In the
fifth chapter, previously discussed physical dimensions are linked to their practical
application and equations applicable to the collision analysis, based on conclusions from
previous chapters. In the sixth chapter, a sample of the analysis of a real collision was
provided, including the answers on specific, frequently asked, relevant questions
STANDING WAVE ON GUITAR STRING
Get PDFU radu je opisano kako žičani glazbeni instrumenti proizvode zvuk. Najprije su uvedeni osnovni
pojmovi valnog gibanja i akustike. Zatim je izveden model malih oscilacija napete žice te je
dobivena valna jednadžba. Pojašnjena je osnovna ideja složenih valnih gibanja i Fourierove
analize. U drugom dijelu govori se o glazbenim intervalima i ljestvicama. Konačno, u
eksperimentalnom dijelu su korišteni Soundcard Scope te Overtone Analyzer.In this work it is described how string instruments produce sound. Firstly, general therms of
wave motion and accoustic are introduced. Afterwards, model of small oscillations is presented
and wave equation is derived. Basic idea of complex wave motion and Fourier analysis is
explained. In second part are discussed ideas of music intervals and scales. Finally, Soundcard
Scope and Overtone Analyzer are used in experimental section
Magnetic levitation
Get PDFTema ovog završnog rada je magnetska levitacija. Na samom početku dan je kratak povijesni
pregled magnetizma, navedena su magnetska svojstva materijala s naglaskom na
dijamagnetizmu, zbog toga što se kod dijamagneta uvodi pojam magnetske levitacije. Na
samom kraju rada nalazi se poglavlje maglev vlakovi, gdje se želi pobliže objasniti na primjeru
primjena magnetske levitacije.Subject of this final thesis is magnetic levitation. In the beginning it contains short historical
overview of magnetism. After that comes description of magnetism and magnetic properties of
materials with emphasis on diamagnetism. Last part of thesis deals with Maglev trains as an
example of application of magnetic levitation
Mjerenje koncentracije aktivnosti radona 222^ Rn u vodi iz prirodnih izvora u općini Slavonski Šamac
Get PDFNa samom početku teorijskog dijela ovog rada opisano je što je radioaktivnost, koje su vrste
radioaktivnih raspada te utjecaj zračenja na ljude. Zatim su opisane kemijske i fizikalne osobine
radona, njegova rasprostranjenost te načini ulaska u zatvorene prostore. U radu su navedene
uobičajene doze zračenja i mehanizmi mitigacije radona.
Nakon toga opisano je kako radon dospijeva u vodu, kakav rizik predstavlja kada se nađe u
vodi te su navedeni podaci o referentnim razinama koncentracije radona.
Kao uvod u eksperimentalni dio iznesene su činjenice o vodi koja se proučava u ovom radu,
način uzorkovanja te način pripreme uzoraka za mjerenje. Potom je opisan princip rada uređaja
koji je korišten u analizi uzoraka. Na kraju su prikazani rezultati uz njihovu statističku obradu.
Kao posljednji dio rada dan je zaključak, te pregled korištene literature.At the very beginning of the theoretical part of this thesis the radioactivity, types of radioactive
decay and effects of radiation on humans have been described. Subsequently, there is a
description of chemical and physical properties of radon, its distribution and ways of radon
entering indoors. The usual radiation doses and mechanisms of radon mitigation are listed in
the thesis. After that, there is a description of how radon reaches water, what are the risks of
radon reaching water and what are the reference levels of radon concentration.
As an introduction to the experimental part of thesis, some facts about the water studied in this
thesis, as well as method of sampling and the way of preparing samples for measuring are
presented. After that, the operating principle of device used in the sample analysis is described.
Finally, the results are presented together with their statistical evaluation. The thesis ends with
conclusion and literature review
Radon in Natural Mineral Waters
Get PDFU teorijskom dijelu diplomskog rada navedene su i opisane vrste radioaktivnog
raspada. Opisane su dozimetrijske veličine, te utjecaj ionizirajućeg zračenja na čovjeka.
Navedene su fizikalno-kemijske karakteristike radona i razlog njegova proučavanja. Nadalje,
u radu je opisano i značenje naziva prirodna mineralna voda.
U eksperimentalnom dijelu rada opisane su metode određivanja koncentracije radona u
vodi tekućinskim scintilacijskim detektorom TriCarb 2900 i AlphaGUARD mjernog uređaja
kao i njihov princip rada. Dobiveni rezultati mjerenja su uspoređeni, te su izračunate godišnje
efektivne doze primljene ingestijom takve vode. Zatim su uspoređene vrijednosti s dozama
primljenima inhalacijom i ingestijom vode iz gradskih vodovoda.In theoretical part of this thesis the types of radioactivity are described. Dosimetric
quantities are described as well as the influence of ionising radiation on humans. The
physical and chemical properties of radon are described and many reason for it's study are
emphasized. Furthermore, the term natural mineral water is described in this thesis.
In the experimental part of this thesis the methods of determination of concentration
radon in water by TriCarb 2900 and AlphaGuard measuring system are described as well as
their principle of operation. Furthermore, the sampled natural mineral waters that are
available on the Croatian market are presented as well as the obtained results. Effective
annual doses due to water ingestion were calculated and the results of measurement
comparison were given. The obtained values were compared with the doses received due to
inhalation and ingestion of water from waterworks
First observation of astropsyhical neutrino in correlation with observation of high energy cosmic gamma - rays
Get PDFVeć se dugo smatra da bi odgovor na pitanje izvora kozmičkih neutrina i visokoener- gijskih gama-zraka mogli biti blazari. U ovom ćemo radu predstaviti detekciju jednog takvog neutrina, koja se dogodila 22. rujna 2017. godine, u sklopu neutrinskog opservatorija Ice Cube, koristeći Čerenkovljev efekt. Prije toga ćemo na teorijskoj razini obraditi neutrino, gama-zračenje te Čerenkovljevo zračenje. Nakon toga ćemo poseban naglasak staviti na astrofizički neutrino i njegovu detekciju. Na kraju ćemo opisati kako je tekao sam postupak detekcije te povezati detekciju kozmičkog neutrina s detekcijom visoko- energijskih gama-zraka, koje uspješno detektiramo već duže vrijeme. Time ćemo pokušati potvrditi da su blazari izvor kozmičkih neutrina te gama-zračenja visokih energija.For a long time it is thought that the source of cosmic neutrinos and high energy gamma
rays could be blazars. In this paper, we will present a detection of such a neutrino, which
occured on September 22nd 2017., in the Ice Cube neutrino observatory, using Cherenkov effect. Firstly, we will define neutrinos, gamma radiation and Cherenkov radiation. Secondly, we will emphasize astrophysical neutrino and its detection. Lastly, we will
describe the steps through the process of its detection and link the detection of cosmical
neutrinos with the detection of high energy gamma rays, which we succesfully detect
for a while. Using this, we will try to confirm that the source of cosmic neutrinos and
high energy gamma radiation are blazars
Spark Counter Radiation Detector
Get PDFU uvodnom dijelu diplomskog rada opisani su radioaktivnost, tipovi radioaktivnosti, ionizacija tvari i
osnovni principi detekcije radioaktivnog zračenja. Naglasak je stavljen na opis principa rada spark detektora
koji detektiraju električne iskre kao posljedicu prolaska zračenja kroz određeno osjetljivo područje
detektora. Glavni dio diplomskog rada daje detaljan opis svih faza dizajna, konstrukcije, testiranja i
implementacije spark detektora. Detaljno su opisani neki pokusi koji se mogu iskoristiti u nastavi, kako bi
se uočile, istražile i objasnile neke pojave i procesi vezani uz radioaktivnost i svojstva radioaktivnog
zračenja, ionizaciju tvari i detekciju zračenja, a s ciljem njihova dubljeg razumijevanja kod učenika i
studenata.The introductory part of the thesis describes radioactivity and its properties, ionization and basic principles
of radiation detection. The emphasis is put on the description of the spark detectors and their detection of
electrical sparks which occur due to passing of radiation through a particularly sensitive area of the detector.
The main part of this paper gives a detailed description of all stages of design, construction, testing and
implementation of a spark detector. A number of experiments suitable for in-class use are described in
detail. They are significant for exploring and explaining certain phenomena and processes related to
radioactivity, ionization and radiation detection, with the aim of enhancing the students' understanding of
these subjects
Neuromagnetizam - neinvazivni uvid u kortikalnu neurodinamiku
Get PDFIstraživanja mozga intenzivnije se razvijaju zadnjih pedesetak godina, a gotovo 90% informacija
koje trenutno znamo o mozgu otkriveno je u zadnjih deset godina 20. stoljeća, dekade nazvane
„Desetljećem mozga“. No, dosadašnja se otkrića smatraju tek početkom i očekuje se da će se
mnoge tajne mozga tek otkriti. Među dosadašnjim otkrićima posebno su se istaknule metode za
neinvazivno funkcionalno oslikavanje mozga. One su nam otvorile cijeli niz novih mogućnosti,
od dinamičkog praćenja promjena normalnih funkcija mozga do razotkrivanja različitih
patoloških stanja kao što su shizofrenija, ovisnosti o drogama, epilepsija itd.The brain research is intensively developing during past fifty years. Hovewer, almost 90% of all
information we currently know about the brain has been discovered in the last decade of the 20th
century, the decade called "The Decade of the Brain". The current findings are considered only
as a beginning and it is expected that many brain secrets just have to be revealed. Among the
discoveries made so far, special emphasis was put on the methods for noninvasive functional
brain imaging. They opened a whole set of new possibilities, ranging from dynamic monitoring
of changes in normal brain functions to the detection of various pathological conditions such as
schizophrenia, drug addiction, epilepsy etc
Observing of Jupiter in the oposition
Get PDFU ovom završnom radu predstavljen je Jupiter. U teorijskom dijelu, nakon kratkog povijesnog
pregleda istraživanja ovog plinovitog diva Sunčevog sustava, navedena su njegova fizička svojstva
i uspoređena s fizičkim svojstvima Zemlje radi jednostavnije vizualizacije Jupitera. Kroz rad
također je pojašnjena unutarnja građa planeta, atmosfera Jupitera te njegovi prsteni i prirodni
sateliti. Na kraju su istaknute i detaljnije opisane pojave kao što je Velika crvena pjega.
Nakon detaljne teorijske podloge objašnjeni su astronomski pojmovi i teleskopi kojima se
promatrao Jupiter u opoziciji. Priložene su fotografije kao rezultat promatranja te analiza istoga.In this paper Jupiter is presented. After short historical overview of this gas giant, in the theoretical
part, properties and comparison with Earth is given in order to visualize Jupiter more easily.
Throughout the paper Jupiter's structure, atmosphere, rings and natural satellites as well as the Big
Red Spot were described.
After detailed theoretical base, astronomical terms and telescopes used for observation of Jupiter
in opposition were explained. Result of this observations are attached in the form of photographs
as well as analysis of formerly mentioned phenomena