Study of a nonhomogeneous aerogel radiator in a proximity focusing RICH detector

The use of a nonhomogeneous aerogel radiator, i.e. one consisting of layers with different refractive indices, has been shown to improve the resolution of the Cherenkov angle measured with a proximity focusing RICH detector. In order to obtain further information on the performance of such a detector, a simple model has been used to calculate the resolution and search for optimal radiator parameters.Comment: Submitted to Nucl. Instr. Met

Ekstremalna svojstva paralelograma upisanih u elipsu

Među mnogobrojnim svojstvima paralelograma upisanih u elipsu, u ovom radu su istaknuta dva koja su povezana s maksimalnim opsegom i maksimalnom površinom paralelograma. Koristeći neke elementarne činjenice o krivuljama drugog reda iz afine i projektivne geometrije, dokazan je Glavni teorem koji kaže da su paralelogrami maksimalnog opsega upisani u elipsu karakterizirani svojstvom da su tangente elipse u susjednim vrhovima paralelograma međusobno okomite, te da je svaka točka elipse vrh točno jednog takvog paralelograma. U radu je opisano i fizikalno tumačenje problema određivanja svih paralelograma maksimalnog opsega upisanih u zadanu elipsu koji je Jean-Marc Richard povezao s problemom iz balistike o određivanju „sigurnog područja“ za familiju putanja hitaca, odnosno satelita. Nadalje, izloženi su još neki alternativni dokazi i poopćenja Glavnog teorema koje su naveli A. Connes i D. Zagier. Opisani su i rezultati N. Anghela čiji je glavni cilj bio poopćenje u smjeru karakterizacije klase krivulja kojima je ortoptička krivulja kružnica. Pozivanjem na nekoliko stavaka iz Bergerove „Geometrije“ zaokružen je pregled prethodno izloženih rezultata te je istaknuta veza s klasičnim Ponceletovim teoremom o poligonima upisanima jednoj, a opisanima drugoj zadanoj krivulji 2. reda. Na kraju rada je izloženo rješenje problema u vezi određivanja paralelograma maksimalne površine upisanih u elipsu koristeći činjenicu da se elipsa može prikazati kao slika kružnice u perspektivnoj afinosti te da je omjer površina invarijanta svakog afinog preslikavanja.Among the many properties of parallelograms inscribed in the ellipse, here are presented two of these which are related to the maximal perimeter and maximal area of the parallelogram. Using some elementary facts about curves of the second order from affine and projective geometry, the Main Theorem is proven, asserting that parallelograms of maximal perimeter, inscribed in an ellipse, are characterized by the fact that the tangents of ellipse at adjacent vertices of the parallelogram are mutually perpendicular. Moreover, each point of the ellipse is a vertex of exactly one such parallelogram. A physical interpretation of the problem of determining all parallelograms of maximal perimeter inscribed in a given ellipse is also described in this paper. Jean-Marc Richard associated this problem to a problem from ballistics, namely determining the “safe domain" for the family of trajectories of projectiles or satellites. Furthermore, some alternative proofs and generalizations of the Main Theorem are presented, as stated by A. Connes and D. Zagier. Some related results of N. Anghel are described as well, his main goal being a characterization of a larger class of curves whose orthoptic curve is a circle. By referring to several items from M. Berger’s ”Geometry”, a review of previously presented results is completed, indicating also a link to the classic Poncelet theorem on polygons inscribed in one given conic and circumscribed about another given conic. In the final chapter, a solution to the problem of determining parallelograms with maximal area inscribed in an ellipse is presented, using a representation of the ellipse as the image of a circle in perspective affinity and the affine invariance of the ratio of areas

The HERA-B Ring Imaging Cherenkov Counter

The HERA-B RICH uses a radiation path length of 2.8 m in C_4F_10 gas and a large 24 square meters spherical mirror for imaging Cherenkov rings. The photon detector consists of 2240 Hamamatsu multi-anode photomultipliers with about 27000 channels. A 2:1 reducing two-lens telescope in front of each PMT increases the sensitive area at the expense of increased pixel size, resulting in a contribution to the resolution which roughly matches that of dispersion. The counter was completed in January of 1999, and its performance has been steady and reliable over the years it has been in operation. The design performance of the RICH was fully reached: the average number of detected photons in the RICH for a beta=1 particle was found to be 33 with a single hit resolution of 0.7 mrad and 1 mrad in the fine and coarse granularity regions, respectively.Comment: 29 pages, 23 figure

Utilization of Miscanthus for Energy Purposes

Predložená práca sa zaoberá predstavením ozdobnice čínskej ako energetickej plodiny. Hlavný doraz je kladený na zhodnotenie energetických parametrov s následným využitím ako biomasové palivo. Výsledkom práce je posúdenie ekonomického potenciálu produkcie tejto plodiny na energetické účely v stredoeurópskych klimatických podmienkach.This bachelor’s thesis introduces Miscanthus as an energy crop. The main goal is to evaluate its energy parameters and further use as a biomass fuel. The result of this thesis is to evaluate the economical potenciál for produtcion of this crop for energy purposes in the climate conditions of Central Europe.

Jednoslojni i višeslojni spremnici od poli(etilen-teeftalat)-a

U staklenoj ambalaži piće se čuvalo stotinama godina pa je već sama pomisao na čuvanje gaziranih pića u PET ambalaži poticala je skeptičnost kod ljudi. Posebno pakiranje piva. Danas je PET sve više u upotrebi jer u potpunosti zadovoljava zahtjeve širokog tržišta. Boce se danas lakše transportiraju s jednog mjesta na drugo jer su opasnosti vezane za puknuća samih boca bitno smanjene u usporedbi s staklenom ambalažom. PET ambalaža koja je namijenjena za pakiranje piva počela se razvijati početkom ovog stoljeća. 2003. godine na tržište su bile plasirane prve PET boce u kojima se nalazilo pivo koje je zadržavalo jednaku kvalitetu i trajnost (4.mj) kao i u staklenim bocama. Te su se godine i kod nas pojavile prve PET boce u koje se punilo Ožujsko pivo. Nedugo nakon toga uporaba PET-a za pivo proširila se i na druge krajeve i zemlje. PET boce u kojoj se nalazilo pivo, bile su pod nazivom (danas već vrlo poznatim) Q-pack

Random number generator

Táto diplomová práca sa zaoberá generovaním náhodných čísel a implementáciou generátoru Fortuna v jazyku Java. Práca sa najprv venuje teoretickému zoznámeniu s problematikou generácie náhodných dát. Potom sú v nej popísané a analyzované rôzne zdroje entropie ako pohyb myšou, písanie na klávesnici, zachytávanie šumu pomocou mikrofónu a zachytávanie šumu pomocou webkamery. Analýza sa zaoberá náhodnosťou, použiteľnosťou a objemom získaných dát. Potom je v práci spomínaný teoretický opis generátoru náhodných čísel Fortuna. Na záver je predstavený a popísaný objektový návrh programu Fortuna a sú tu spomenuté aj všetky implementačné detaily s tým súvisiace.This master thesis deals with a generation of random numbers and Fortuna generator implementation in Java language. In the first part the theoretical familiarization to the issues is introduced. Various entropy sources like mouse movement, keyboard typing, microphone and web camera noise are described and analysed. The analysis focuses on randomness, usability and volume of gathered data. Also the Fortuna random number generator is described from the theoretical view. Object analysis and implementation details are described in the last chapter of the document.

Analysis of Private Information from FAT32

Cílem této práce bylo vytvořit aplikaci pracující se souborovým systémem FAT32, ve kterém vyhledá požadované soubory a obnoví je. Následně z těchto souborů získá citlivé informace. Nejprve jsou popsány principy FAT32 a způsob ukládání informací ve zkoumaných aplikacích. V posledních kapitolách je návrh, implementace a testování aplikace.The aim of this thesis was to create an application which can search for and recover specific files in the file system FAT32, and subsequently extract sensitive information from these files. The first part of this thesis describes the principles underlying FAT32, and focuses on how the analysed applications store information. The second part outlines the application and describes its implementation and simulations.

Intentional Communities and Liberal Policies of Cultural Support

Some theoreticians argue that the stability of liberalism is to a large extent an outcome of a continued existence of traditional and other forms of life in communities, which are able to slow down or hinder the immoderate expansion of individualism, but that liberal societies are liable to destroy that foundation of their stability. However, liberal society cannot allow the destruction of the existing forms of communal and communitarian life, because it would mean its destabilization. On the contrary, where traditional communities do not play their stabilising role, liberal societies must change their social and cultural policy in order to generate some new forms of communitarian and communal life. The article deals with some constructive and destructive influences of liberalism on the communities constituted around separate concepts of the good. It shows that modern societies may be fertile soil for a variety of cultural and other communities