11. Study on multi-ELVES in the Pierre Auger ObservatoryA. Vásquez Ramírez, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, objavljeni znanstveni prispevek na konferenci Opis: Since 2013, the four sites of the Fluorescence Detector (FD) of the Pierre Auger Observatory record ELVES with a dedicated trigger. These UV light emissions are correlated to distant lightning strikes. The length of recorded traces has been increased from 100 μs (2013), to 300 μs (2014-16), to 900 μs (2017-present), to progressively extend the observation of the light emission towards the vertical of the causative lightning and beyond. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. The nature of the multi-ELVES is not completely understood but may be related to the different types of lightning in which they are originated. For example, it is known that Narrow Bipolar Events can produce double ELVES, and Energetic In-cloud Pulses, occurring between the main negative and upper positive charge layer of clouds, can induce double and even quadruple ELVES in the ionosphere. This report shows the seasonal and daily dependence of the time gap, amplitude ratio, and correlation between the pulse widths of the peaks in a sample of 1000+ multi-ELVES events recorded during the period 2014-20. The events have been compared with data from other satellite and ground-based sensing devices to study the correlation of their properties with lightning observables such as altitude and polarity.
Ključne besede: Pierre Auger Observatory, indirect detection, fluorescence detection, UV light, multi-ELVES, lightning
Objavljeno v RUNG: 03.10.2023; Ogledov: 1441; Prenosov: 5
 Celotno besedilo (1,25 MB)
Gradivo ima več datotek! Več... |
12. Cosmic Ray Composition between 2 PeV and 2 EeV measured by the TALE Fluorescence DetectorT. AbuZayyad, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci Opis: The Telescope Array (TA) cosmic rays detector located in the State
of Utah in the United States is the largest ultra high energy cosmic rays
detector in the northern hemisphere. The Telescope Array Low Energy Extension
(TALE) fluorescence detector (FD) was added to TA in order to lower the
detector's energy threshold, and has succeeded in measuring the cosmic rays
energy spectrum down to PeV energies, by making use of the direct Cherenkov
light produced by air showers. In this contribution we present the results
of a measurement of the cosmic-ray composition using TALE FD data collected
over a period of ∼7 years. TALE FD data is used to measure the Xmax distributions of showers seen in the energy range of 10^15.3 - 10^18.3 eV. The data distributions are fit to Monte Carlo distributions of {H, He, N, Fe} cosmic-ray primaries for energies up to 10^18 eV. Mean Xmax values are measured for the full energy range. TALE observes a light composition at the "Knee", that gets gradually heavier as energy increases toward the "Second-Knee". An increase in the Xmax elongation rate is observed at energies just above 10^17.3 eV indicating a change in the cosmic rays composition from a heavier to a lighter mix of primaries.
Ključne besede: Telescope Array, TALE, low energy extension, indirect detection, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, composition
Objavljeno v RUNG: 02.10.2023; Ogledov: 1408; Prenosov: 6
Celotno besedilo (960,82 KB)
Gradivo ima več datotek! Več... |
13. Cosmic Ray Energy Spectrum measured by the TALE Fluorescence DetectorT. AbuZayyad, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci Opis: The Telescope Array (TA) cosmic rays detector located in the State
of Utah in the United States is the largest ultra high energy cosmic rays
detector in the northern hemisphere. The Telescope Array Low Energy Extension
(TALE) fluorescence detector (FD) was added to TA in order to lower the
detector's energy threshold, and has succeeded in measuring the cosmic rays
energy spectrum down to PeV energies, by making use of the direct Cherenkov
light produced by air showers. In this contribution we present the results
of a measurement of the cosmic-ray energy spectrum using TALE FD data
collected over a period of ∼7 years. The data set used for this
measurement is the same one used for the mass composition measurement that is
presented, as a separate contribution, at this conference. The energy
spectrum shows features consistent with the "knee" and the "second knee"; a
similar result to our previous energy spectrum publication. This time
using a different hadronic model, and different event selection criteria as
explained in the text of this proceeding.
Ključne besede: Telescope Array, TALE, low energy extension, indirect detection, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, energy spectrum
Objavljeno v RUNG: 02.10.2023; Ogledov: 1412; Prenosov: 7
Celotno besedilo (2,92 MB)
Gradivo ima več datotek! Več... |
14. Cosmic Ray Composition in the Second Knee Region as Measured by the TALE Hybrid DetectorR. Abbasi, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci Opis: The Telescope Array Low-energy Extension (TALE) experiment is a hybrid air shower detector for the observation of air showers induced by cosmic rays with energy above 10^16 eV. The TALE detector consists of a Fluorescence Detector (FD) station with 10 FD telescopes located at the TA Middle Drum FD Station (itself made up of 14 FD telescopes), and a Surface Detector (SD) array made up of 80 scintillation counters, including 40 with 400 m spacing and 40 with 600 m spacing. A triggering system for the TALE-SD using an external trigger from the TALE-FD, a so-called hybrid trigger, allows for a lower energy threshold. The TALE hybrid trigger system has been working since 2018. Here we present an estimate of the performance of hybrid detection using a Monte Carlo simulation, and a first measurement of the cosmic ray composition and spectrum using the TALE-Hybrid detector.
Ključne besede: Telescope Array, TALE, low energy extension, indirect detection, hybrid detection, ground array, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, energy spectrum, composition
Objavljeno v RUNG: 02.10.2023; Ogledov: 1467; Prenosov: 6
Celotno besedilo (2,41 MB)
Gradivo ima več datotek! Več... |
15. Highlights from the Telescope Array experimentGrigory I. Rubtsov, R. U. Abbasi, T. Abu-Zayyad, M. Allen, Yasuhiko Arai, R. Arimura, E. Barcikowski, J. W. Belz, Douglas R. Bergman, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci (vabljeno predavanje) Opis: The Telescope Array (TA) is the largest cosmic ray observatory in the Northern Hemisphere. It is designed to measure the properties of cosmic rays over a wide range of energies. TA with it's low energy extension (TALE) observe cosmic-ray induced extensive air showers between 2 PeV and 100 EeV in hybrid mode using multiple instruments, including an array of scintillator detectors at the Earth's surface and telescopes to measure the fluorescence and Cerenkov light. The statistics at the highest energies is being enhanced with the ongoing construction of the TAx4 experiment which will quadruple the surface area of the detector. We review the present status of the experiments and most recent physics results on the cosmic ray anisotropy, chemical composition and energy spectrum. Notable highlights include a new feature in the energy spectrum at about 10^19.2 eV, and a new clustering of events in the direction of Perseus-Pisces supercluster above this energy. We also report on updated diffuse photon flux limits and new spectrum and composition results in the lower energy range from the TALE extension.
Ključne besede: Telescope Array, TALE, low energy extension, TAx4, indirect detection, hybrid detection, ground array, fluorescence detection, Cherenkov light, ultra-high energy, cosmic rays, energy spectrum, composition, anisotropy
Objavljeno v RUNG: 26.09.2023; Ogledov: 1329; Prenosov: 6
Celotno besedilo (6,75 MB)
Gradivo ima več datotek! Več... |
16. |
17. From futile to fruitful: Diesel soot as white light emitterMohanachandran Nair Sindhu Swapna, Sankararaman S, 2018, izvirni znanstveni članek Opis: The present work describes a solution for the effective use of the hazardous particulate matter (diesel soot) from the internal combustion engines (ICEs) as a potential material emitting white light for white light emitting diodes (WLEDs). The washed soot samples are subjected to Field Emission Scanning Electron Microscopy (FESEM), High- Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive Spectroscopy (EDS), UV-Visible, Photoluminescent (PL) Spectroscopy and quantum yield measurements. The CIE plot and Correlated Color Temperature (CCT) reveals the white fluorescence on photoexcitation. The sample on ultraviolet (UV) laser excitation, provides a visual confirmation of white light emission from the sample. The diesel soot collected from public transport buses of different years of manufacture invariably exhibit white fluorescence at an excitation of 350 nm. The sample show a quantum yield of 47.09%. The study is significant in the context of pollution and search for low-cost, rare-earth phosphor free material for white light emission and thereby turning the hazardous, futile material into a fruitful material that can be used for potential applications in photonics and electronics.
Ključne besede: White light emitter, Diesel soot, CIE plot, Quantum yield, Fluorescence
Objavljeno v RUNG: 30.06.2022; Ogledov: 1797; Prenosov: 0
Gradivo ima več datotek! Več... |
18. Blue light emitting diesel soot for photonic applicationsMohanachandran Nair Sindhu Swapna, Sankararaman S, 2018, izvirni znanstveni članek Opis: The present work is the first report of producing blue light emission from phosphor free and low-cost material—the diesel soot from the internal combustion engines (ICEs). The structural morphology is analyzed by field emission scanning electron microscopy and high-resolution transmission electron microscopy. The optical characterization is done by recording UV–visible spectrum and photoluminescent Spectrum. The CIE plot and the power spectrum for the sample show blue emission. This is further verified by collecting diesel soot from the ICE of different year of make. A visual confirmation of blue emission is obtained by exciting the sample with UV laser. The presence of various allotropic forms of carbon in the sample is identified by x-ray diffraction, Fourier transform infrared and Raman spectroscopic analysis.
Ključne besede: blue light emitter, diesel soot, photoluminescence, CIE plot
Objavljeno v RUNG: 30.06.2022; Ogledov: 1611; Prenosov: 0
Gradivo ima več datotek! Več... |
19. Camphor soot: A Tunable Light EmitterMohanachandran Nair Sindhu Swapna, SARITHA DEVI H V, Sankararaman S, 2018, izvirni znanstveni članek Opis: The work in this paper is the first report on the green synthesis of the blue light emitter from waxy, flammable solid collected
from Cinnamomum camphora by controlled combustion for photonic applications. Analysis with field emission scanning
electron microscope and high-resolution transmission electron microscope provides the morphology, whereas the thermo-gravimetric analysis gives the thermal stability of the soot. The optical and structural characterizations are done by recording
UV–Visible, Photoluminescent, and Raman Spectrum. The CIE plot and the power spectrum of the sample show a blue
emission at an excitation of 350 nm at room temperature with a quantum yield of 46.15%. The dependence of luminescent
behavior on temperature and excitation wavelength reveals that the material is a tunable blue emitter. This green synthesis of
the blue light emitter is highly significant, when the world is in search of a simple, phosphor-free, non-toxic, cost-effective
material with good quantum efficiency
Ključne besede: camphor, soot, blue light emitter
Objavljeno v RUNG: 30.06.2022; Ogledov: 1613; Prenosov: 0
Gradivo ima več datotek! Več... |
20. Use of color in animation : diploma thesisMaja Grčki, 2022, diplomsko delo Opis: Color is a powerful tool that helps us set the mood, however, its importance is often left unnoticed while watching any form of media (movies, photography, commercials, books, etc.). Both art theory and human psychology show evidence that color and lighting have a large impact on the perception of the viewer which is why this thesis will focus on exploring what impact color and correct lighting of a scene have on people's minds and how it can be used in animation to convey the correct emotions and enhance the viewer’s experience. Throughout this thesis we will cover topics related to color theory, light and how animation studios work on their films in terms of color and lighting. Each chapter will help understand and learn about different uses of color, such as color psychology and symbolism of colors, color scripts, and lighting, and in the end, a case study to conclude everything mentioned before. To do so, this thesis will take a look at Pixar and Disney and their movies such as Coco (Pixar, 2017), Tangled (Walt Disney, 2010) and Finding Nemo (Pixar, 2003) as well as different color theory studies. We will also use the example of the practical part of the diploma work, animated music video Crystal Clear, to see how the colors were used and what the thought process behind it was.
Ključne besede: Color, Animation, Mood, Psychology, Light, Pixar, Disney, ColorScript
Objavljeno v RUNG: 22.02.2022; Ogledov: 3225; Prenosov: 144
 Povezava na celotno besedilo
Gradivo ima več datotek! Več... |
