209 research outputs found
METU DBL üzerinde berilyum temelli nötron üretim ışın hattının tasarımı ve simülasyonları
No full textThere are various sources of neutron irradiation for different neutron beam applications, each with their own limitations. Limited access to nuclear reactors, the need to adjust the flux and energy of neutrons, shielding requirements and high costs of laboratory neutron source Cf-252, which has an average neutron kinetic energy of 2.1 MeV that limits its applicability for high energy neutron applications, have led researches to study and adapt accelerator based neutron sources. An ideal source should have an adjustable flux and energy spectrum. One key channel is the 9Be(p, n)9B. By utilizing the METU Defocusing Beam-Line which uses proton cyclotron at TENMAK-NUKEN Proton Accelerator Facility, a beryllium based neutron irradiation station is proposed. This study focuses on design and simulations of a solid target system with optimal parameters such that highest neutron yield with lowest production rate of residual impurity and lowest activity can be achieved during its operation. Using Monte Carlo simulation toolkits such as FLUKA, Geant4, SRIM/TRIM and deterministic nuclear reaction modelling code TALYS, anticipated outcome of the proposed experiment has been extensively studied and are reported here. This thesis reports that by utilizing a 30 MeV, 150 μA proton beam, a beryllium based target setup stationed on METU-DBL can supply neutrons with energy spectrum starting from the epithermal (which can be further decreased to thermal using a moderator), extending to fast and ultra-fast range with a total integrated neutron flux of up to 3x10^10 n/cm2/s at a point on the outer surface of the target station.Farklı nötron ışınlama alanları için birçok nötron kaynağı çözümü bulunmaktadır fakat bu çözümlerin her biri belirli sınırlamaları beraberinde getirir. Nükleer reaktöre ulaşımın sınırlı olduğu, değiştirilebilir nötron akısı ve enerjisi gerekliliği, 2.1 MeV ortalama nötron enerjisine sahip olan ve yüksek enerjili nötron uygulamaları için uygun olmayan Cf-252 laboratuvar kaynağının yüksek maliyeti ve zırhlama gereklilikleri ara¸stırmacıları, hızlandırıcı temelli nötron kaynaklarını araştırıp kullanmaya teşvik etmiştir. İdeal bir nötron kaynağı ayarlanabilir akı ve enerji spektrumuna sahip olmalıdır. Bu temel kanallardan 9Be(p, n)9B öne çıkmaktadır. TENMAK-NÜKEN’de bulunan Proton Hızlandırcı Tesisinde yer alan hızlandırıcı ve onun bir kolu olan ODTÜ Saçılmalı Demet Hattı kullanılarak berilyum temelli bir nötron ışınlama istasyonu önerilmektedir. Bu çalışma, böyle bir katı hedef sisteminin operasyonel haldeyken, optimal parametreler kullanularak en yüksek nötron veriminin elde edilmesine, safsızlık ve ortamda radyoaktiviteye yol açan kalıntı çekirdeklerin en düşük miktarda üretimine odaklanmaktadır. Monte Carlo temelli FLUKA, Geant4, SRIM/TRIM ve deterministik nükleer reaksiyon modelleme kodları TALYS gibi simülasyon kodları kullanılarak önerilen deneyin beklenen çıktıları kapsamlı bir şekilde çalışılmış ve bildirilmiştir. Bu tez, 30 MeV enerjiye sahip 150 μA proton akımı kullanarak METU-DBL’e kurulacak bir berilyum hedef istasyonunun ürettiği nötronların epitermal enerjilerden, hızlı ve ultra-hızlı enerji seviyelerine uzandığını, ve nötron akısının ışınlama istasyonunun yüzeyinde bir noktada 3x10^10 n/cm2/s seviyesine varabileceğini bildirmektedir. Bu tez aynı zamanda nötronların polietilen moderatörden geçirilerek termal enerji seviyelerine indirgenebileceğini öngörmektedir.M.S. - Master of Scienc
Searching for topological dark matter in LIGO data
No full textGravitational-wave interferometers have been recently proposed as a promising probe in searches for dark matter. These highly sensitive instruments are potentially able to detect the interactions of dark matter with the detector's hardware. In this work, we explore the possibilities of discovering topological dark matter with the LIGO detectors. We analyze domain walls consisting of dark matter passing through the Earth, leaving traces in multiple detectors simultaneously. Considering dark matter interactions with light in the interferometer, and with the beam splitter, we perform the first analysis of topological dark matter with gravitational-wave strain data. We examine whether astrophysically unexpected triggers could be explained by domain-wall passages. We find that all of the binary black hole mergers we analyze favor the binary black hole merger hypothesis rather than the domain-wall hypothesis, with the closest being GW190521. Moreover, we find that some topological dark matter signals can be caught by binary black hole searches. Finally, we find that special types of glitches in the measurement data can inevitably limit the dark matter searches for certain parameters. These results are expected to guide future searches and analyses
Searching for topological dark matter in LIGO data
No full textGravitational-wave interferometers have been recently proposed as a promising probe in searches for dark matter. These highly sensitive instruments are potentially able to detect the interactions of dark matter with the detector\u27s hardware. In this work, we explore the possibilities of discovering topological dark matter with the LIGO detectors. We analyze domain walls consisting of dark matter passing through the Earth, leaving traces in multiple detectors simultaneously. Considering dark matter interactions with light in the interferometer, and with the beam splitter, we perform the first analysis of topological dark matter with gravitational-wave strain data. We examine whether astrophysically unexpected triggers could be explained by domain-wall passages. We find that all of the binary black hole mergers we analyze favor the binary black hole merger hypothesis rather than the domain-wall hypothesis, with the closest being GW190521. Moreover, we find that some topological dark matter signals can be caught by binary black hole searches. Finally, we find that special types of glitches in the measurement data can inevitably limit the dark matter searches for certain parameters. These results are expected to guide future searches and analyses.16 pages with 14 figure
Detecting fundamental vector fields with LISA
No full textISSN:1550-7998ISSN:0556-2821ISSN:1550-2368ISSN:0556-2821ISSN:1550-236
Osmanlı Devleti’nde Okutulan İlk Fizik Ders Kitabı: Usûl-i Hikmet-i Tabiiye (Doğa Felsefesine Giriş)
No full textBu makalede modernleşmenin eğitim üstündeki etki ve sonuçları paralelinde Osmanlı Devleti’nde modern bilimlere ve fizik eğitimine nasıl bakıldığı, dönemin ilk fizik ders kitabı olan Usûl-ü Hikmet-i Tabiiye (Doğa Felsefesine Giriş) aracılığıyla açıklanmaya çalışılmıştır. Modernleşmenin anahtarı olan eğitsel gelişmeler, ülkede eski eğitim kurumlarının yanı sıra yeni eğitim kurumlarının açılmasına da öncülük etmiştir. Söz konusu yeni eğitim kurumlarının materyal ihtiyacı yeni ders kitaplarını bir zorunluluk haline getirmiştir. Usûl-ü Hikmet-i Tabiiye bu ders kitaplarından birisidir. 1885 yılında ilk baskısı yapılan kitabın yazarı Mehmet Emin Derviş Paşa’dır. Mühendishanelerde okutulmak için hazırlanan eser, yalın anlatımı ve ele aldığı konuların çeşitliliği, fotoğraflarla zenginleştirilmiş içeriği bakımından da değerlidir. Anahtar Kelimeler: Modernleşme, Eğitim, Felsefe, Doğa Felsefesi, Fizik The First Physics Textbook in Ottoman State: Usûl-ü Hikmet-i Tabiiye (Introduction to the Philosophy of Nature)Abstract: In this article how modern sciences and physics education was perceived in the Ottoman Empire in parallel with the effects and results of modernization on education is tried to be explained through the era’s the first physics textbook called Usûl-ü Hikmet-i Tabiiye (Introduction to the Philosophy of Nature). “Education”, being the key to the modernization, pioneered to the foundation of new educational institutions as well as the older educational institutions. The material need of the new educational institutions in question necessitated the use of new textbooks. In this respect, Usûl-ü Hikmet-i Tabiiye is one of these textbooks. The author of the book, whose first publication was in 1885, is Mehmet Emin Derviş Paşa. This work, prepared to be taught in engineer schools, is valuable for its plain expression, variety of subjects it deals with and its content enriched with photographs. Keywords: Modernization, Education, Philosophy, Nature Philosophy, Physic
A Quest through Interconnected Datasets: Research on Annotation Practices in Highly Cited Audio Machine Learning Work and Their Utilized Datasets: Annotation Practices in Datasets Utilized by The International Conference on Acoustics, Speech, and Signal Processing (ICASSP) Conferences: A Transparency Analysis
No full textThis research examines transparency between ICASSP conference papers and the dataset documentations related to the datasets' annotation practices. Top-cited 5 papers and 51 unique resources in total were considered. All of the selected papers utilized at least one dataset. For every paper, an extensive metadata search has done to reach the initial datasource of those datasets. These searches happened both within the paper contents such as sections and references along with outside the paper contents through the way of extensive web queries. Analysis of the papers published from 2021 and 2022 and their relevant datasets revealed varying levels of transparency. Original dataset creators provide comprehensive information, while papers using modified datasets offer limited details on initial annotations. Emphasizing the need for accountability, this study suggests that papers utilizing datasets should trace back to the initial dataset and provide explicit comments. The findings underscore the importance of ensuring sufficient information in initial datasets and promoting transparency and traceability in dataset annotation practices within the ICASSP community.CSE3000 Research ProjectComputer Science and Engineerin
Elevated : increased significances with multi-messenger coincidences
No full textCoincident multi-messenger observation of cosmic sources can offer numerous
benefits. One significant advantage is enhancing the detection significance of
separate detectors by correlating their data and assuming a joint emission. We
have formulated an approach for updating the Bayesian posterior probability of
an astrophysical origin, namely , relying on multi-messenger
coincidences. We demonstrated this with candidate coincident gravitational
waves and high-energy neutrinos. Applying our method to the public data of
candidate coincident high-energy neutrinos with subthreshold gravitational-wave
triggers, we found that in the case of highly energetic neutrino coincidences,
can increase from approximately to . This
marked improvement makes subthreshold detections much more confident.Comment: 7 pages, 1 figure, 1 tabl
Neutrino emission upper limits with maximum likelihood estimators for joint astrophysical neutrino searches with large sky localizations
No full textSince the start of the gravitational wave observation era, no joint high energy neutrino and gravitational wave event has been found. These non-detections could be used for setting an upper bound on the neutrino emission properties for gravitational wave events individually or for a set of them. Although in the previous joint high energy neutrino and gravitational wave event searches upper limits have been found, there is a lack of consistent method for the calculation. The problem addressed in this paper is finding those limits for astrophysical events which are localized poorly in the sky where the sensitivities of the neutrino detectors change significantly and can also emit neutrinos, for example the gravitational wave detections. Here we describe methods for assigning limits for expected neutrino count, emission fluence and isotropically equivalent emission based on maximum likelihood estimators. Then we apply described methods on the three GW detections from aLIGO's first observing run (O1) and find upper limits for them
Transmission dynamics of COVID-19 pandemic with combined effects of relapse, reinfection and environmental contribution: A modeling analysis
No full textReinfection and reactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have recently raised public health pressing concerns in the fight against the current pandemic globally. In this study, we propose a new dynamic model to study the transmission of the coronavirus disease 2019 (COVID-19) pandemic. The model incorporates possible relapse, reinfection and environmental contribution to assess the combined effects on the overall transmission dynamics of SARS-CoV-2. The model’s local asymptotic stability is analyzed qualitatively. We derive the formula for the basic reproduction number ([Formula: see text]) and final size epidemic relation, which are vital epidemiological quantities that are used to reveal disease transmission status and guide control strategies. Furthermore, the model is validated using the COVID-19 reported situations in Saudi Arabia. Moreover, sensitivity analysis is examined by implementing a partial rank correlation coefficient technique to obtain the ultimate rank model parameters to control or mitigate the pandemic effectively. Finally, we employ a standard Euler technique for numerical simulations of the model to elucidate the influence of some crucial parameters on the overall transmission dynamics. Our results highlight that contact rate, hospitalization rate, and reactivation rate are the fundamental parameters that need particular emphasis for the prevention, mitigation and control
Izak Y. Gabay, Yildiz i sus sekretos: el reino de Abdul Hamid: description and datingIzak Y. Gabay, Yildiz i sus sekretos: el reino de Abdul Hamid: description and dating
No full text<p><em>Yildiz i sus sekretos: el reino de Abdul Hamid</em> (<em>Yildiz and its secrets: the reign of Abdülhamid)</em>, is one of the few documents found about the late Ottoman Empire written by a Sephardic Jewish author. It supposes an important document for the studies about General Universal History, especially for the one related to the Ottoman Empire and the intercultural relations which existed within it. In this article we will proceed to the presentation of the contents of this book, one of the last representatives works more significant written in Judeo-Spanish <em>aljamia </em>with Hebrew letters, by gathering some points of interest such as the fixing of certain crucial dates in the history of the book.</p>
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