Ultraluminous X-ray sources (ULXs) are extragalactic, non-nuclear, point-like X-ray sources whose luminosity supersedes that of the Eddington limit of an accreting stellar mass black hole (L&gt; 10 ^ 39 erg / s). Most of them are powered by black holes and neutron stars undergoing genuine super-Eddington accretion, with a small handful of candidates being consistent with sub-Eddington accretion on an intermediate mass black hole. In this thesis, we explore the populations of ULXs in the sky surveys of ESA's X-ray satellite, XMM-Newton, and the MPE's newly launched X-ray telescope, eROSITA. We do so by correlating them with the HECATE list of galaxiesto build two X-ray non-nuclear catalogs, and comparing the yields with very expensive surveys and previous works. To build a catalog, we useother reference lists of contaminant objects, such as the Gaia data releases, the SIMBAD database or the SDSS survey to look for contaminating objects of diverse nature, such as foreground stars or background quasars, in order to make sure that our resulting ULX samples are as clean as possiblewith catalog data only. Our results include the attestation that the XMM-Newton ninth data release provides an improvement in quantity and quality with respect to older data releases used in previous works, and that the eROSITA survey is currently in a very preliminary stage. The two new catalogs contain 12,952 and 3,720 non-nuclear X-ray sources, out of which 914 and 132 are ULX candidates with an expected ~ 25% fraction of undetected contaminants. This constitutes a very significant contribution to the already known 300 ULX candidates. Since the sky coverage and depth of the XMM-Newton and eROSITA surveys are vastly different, only 19 of the ULX candidates are shared between the catalogs. ULX candidates are preferentially found in star-forming galaxies, but a subset of very bright objects (L&gt; 5x10 ^ 40 erg / s) try to be more common in elliptical galaxies, in contradiction to what has been established in the literature. / <p>This thesis was written under the joint supervision of Erin O'Sullivan at Uppsala University and Axel Schwope at the Leibniz Institute for Astrophysics in Potsdam. The presentation was held online due to the COVID-19 circumstances.</p> / Master Thesis

The main goal of this thesis is to compare 5 chosen grinding wheels, that vary by the material and structure. The testing is done in the company SLB, spol. s r.o., using a grinder on the holes BDU 80, which is set to 6 different settings of the grinding cycle, defined by the letters A´, A, B, C, D and E. These settings vary by the cutting conditions and enable to compare the tested grinding wheels by 8 measured parameters of the surface quality of the grinded bearing orbits of outer rings of the SLB 84-74 bearings, that are described by the drawing documentation.

This diploma thesis deals with the design and realization of a detachable joint for transferring a large torque from a drive to a driven member in a vertical forging press. The first part analyzes the disadvantages of production, assembly and disassembly of the original wedge joint of eccentric shaft and gear. The design of a new detachable joint is intended to remove the disadvantages of the original joint. Verification calculations are part of the proposal. The next part deals with the production of joint elements and the modification of the connected components for the designed joint.

Die Arbeit untersucht den Einfluss von von radialen, im Zahngrund auslaufenden Schmierölbohrungen auf die Zahnfußtragfähigkeit außenverzahnter Stirnräder durch theoretische und experimentelle Untersuchungen. Es werden Formeln entwickelt, die ohne zeitaufwändige Berechnungen eine sichere Beurteilung des Einflusses von Schmierölbohrungen auf die Zahnfußtragfähigkeit ermöglichen. Dazu wird ein Einflussfaktor Y_OeB ermittelt, welcher die einfache Integration in vorhandene Berechnungsstandards erlaubt. Als Vorlage dient dabei die Berechnung der Zahnfußtragfähigkeit nach DIN 3990 / ISO 6336, die durch diesen Faktor ergänzt werden kann. Neben experimentellen Versuchen zum Einfluss der geometrischen Größen Zahnfußausrundungsradius und Bohrungsdurchmesser werden auch verschiedene Parameter wie die Kranzdicke, zusätzliche Torsionsbelastungen (z. B. an Sonnenwellen), die Wärmebehandlung und die Belastungsart (Schwell- oder Wechsellast) berücksichtigt. Darüber hinaus betrachtet die Arbeit das Verhalten verschiedener Werkstoffe bei Vorhandensein einer Schmierölbohrung. Sie liefert des Weiteren einen Erklärungsansatz zum Einfluss der Schmierölbohrungen auf die Zahnfußtragfähigkeit auf Basis der Veränderung der Eigenspannungsverteilung im Zahnfußgebiet durch die radiale Bohrung und bietet dafür auch ein Modell zur qualitativen Berechnung der Eigenspannungsverteilung auf Basis der FE-Methode an.:1 EINLEITUNG 1 1.1 WISSENSCHAFTLICHE PROBLEMSTELLUNG 1 1.2 ZIELSETZUNG 1 2 STAND DER TECHNIK UND DER BISHERIGEN FORSCHUNG 3 2.1 KERBEN UND KERBWIRKUNG 3 2.1.1 Einzelkerben 3 2.1.2 Mehrfachkerben 4 3 PRÄZISIERUNG DER AUFGABENSTELLUNG 6 4 NUMERISCHE UNTERSUCHUNGEN DER ZAHNRÄDER 7 4.1 GRUNDLAGEN DER FINITE ELEMENTE METHODE 7 4.2 FEM-MODELLBILDUNG – ELEMENTTYPEN 8 4.3 PARAMETERSTUDIE – GRUNDLEGENDE UNTERSUCHUNGEN 10 4.3.1 Variation der Umfangslage der Bohrung 17 4.3.2 Zusammenfassung der Parametervariationen 19 4.4 UNTERSUCHUNGEN ZUM EINFLUSS DER ZAHNBREITE 22 4.5 UNTERSUCHUNG DES SPANNUNGSGRADIENTEN 23 4.6 EINFLUSS EINER FASE AM AUSLAUF DER BOHRUNG IM ZAHNGRUND 25 4.7 SCHMIERÖLBOHRUNG UND VERZAHNUNGSMODIFIKATIONEN 27 5 EXPERIMENTELLE UNTERSUCHUNGEN 28 5.1 ALLGEMEINE VORBEMERKUNGEN 28 5.1.1 Versuchsvorrichtung für Schwelllastversuche 30 5.1.2 Prüfvorrichtung für Wechsellastversuche 31 5.2 KONTROLLE DER BREITENLASTVERTEILUNG 33 5.2.1 Lastverteilung am Zahnkopf 34 5.2.1.1 2D-Kontaktrechnung – Ermittlung des Hebelarmes unter Last 35 5.2.1.2 3D-Kontaktrechnung – Breitenlastverteilung am Zahnkopf 36 5.3 AUSWERTUNG DER VERSUCHE 38 5.3.1 Zeitfestigkeitsgebiet 38 5.3.1 Dauerfestigkeitsgebiet 39 5.4 ERGEBNISSE DER EXPERIMENTELLEN UNTERSUCHUNGEN 42 5.4.1 Geometrievariationen 42 5.4.2 Untersuchung anderer Parameter 43 5.4.3 Einfluss des Werkstoffes 47 5.4.4 Ergebnisse der Wechsellastversuche 51 5.5 STREUUNG DER MESSERGEBNISSE 53 5.6 ERGEBNISSE DER WERKSTOFFTECHNISCHEN UNTERSUCHUNGEN 54 5.6.1 Ergebnisse für 18CrNiMo7-6 54 5.6.2 Ergebnisse für 16MnCr5 55 5.6.3 Ergebnisse für 42CrMo4 55 5.6.4 Ergebnisse für 31CrMoV9 55 5.6.5 Untersuchung des Bruchbildes 56 5.7 UNTERSUCHUNG DES EIGENSPANNUNGSZUSTANDES 57 5.7.1 Experimentelle Untersuchungen 57 5.7.2 Theoretische Untersuchung der Verteilung der Eigenspannungen 60 5.7.2.1 Ringmodell 62 5.7.2.2 L-Modell 66 5.7.2.3 Zahnlückenmodell 70 5.7.2.4 Zahnradsegmentmodell 73 6 ZUSAMMENFASSUNG 77 7 AUSBLICK 80 8 LITERATUR 84 9 ABBILDUNGSVERZEICHNIS 89 10 TABELLENVERZEICHNIS 91 11 ANHANG 92

Going beyond previous statements, a way is presented which allows statements about smallest possible black holes. It turns out that they exist (theoretically) and that they represent a new stable elementary particle (called G-boson in this work), which shows connections to dark matter and makes dark energy necessary to explain astronomical observations, independent of its existence required in macroquantum theory. This results in logical sequences in the Big Bang, which make it appear in a somewhat different context than previously known.:Table of Contents 1. Abstract 2. Introduction 3. Preliminary consideration on the basis of Planck units 4. The boundary force 5. Boundary force and black holes, the G-boson 6. Properties of the G-boson 7. Origin of the G-bosons, the dark matter and energy 8. What does this mean for the big bang? 9. Astronomical findings 10. Summary

The work of this dissertation will study various aspects of the dynamics of compact objects using numerical simulations.We consider BH dynamics within two modified or alternative theories of gravity. Within a family of Einstein-Maxwell-Dilaton-Axion theories, we find that the GW waveforms from binary black hole (BBH) mergers differ from the standard GW waveform prediction of GR for especially large axion values. For more astrophysically realistic (i.e. smaller) values, the differences become negligible and undetectable. Weestablish the existence of a well-posed initial value problem for a second alternative theory fo gravity (quadratic gravity) and demonstrate in spherical symmetry that a linear instability is effectively removed on consideration of the full nonlinear theory.We describe the key components and development of a code for studying BBH mergers for which the mass ratio of the binaries is not close to one. Such intermediate mass ratio inspirals (IMRIs) are much more difficult to simulate and present greater demands on resolution, distributed computing, accuracy and efficiency. To this end, we present a highly-scalable framework that combines a parallel octree-refined adaptive mesh with a wavelet adaptive multiresolution approach. We give results for IMRIs with mass ratios up to 100:1. We study the ejecta from BNS in Newtonian gravity. Using smoothed particle hydrodynamics we develop and present the highly scalable FleCSPH code to simulate such mergers. As part of the ejecta analysis, we consider these mergers and their aftermath as prime candidates for heavy element creation and calculate r-process nucleosynthesis within the post-merger ejecta. Lastly we consider a non-standard, yet increasingly explored, interaction between a BH and a NS that serves as a toy model for primordial black holes (PBH) and their possible role as dark matter candidates. We present results from a study of such systems in which a small BH forms at the center of a NS. Evolving the spherically symmetric system in full GR, we follow the complete dynamics as the small BH consumes the NS from within. Using numerical simulations, we examine the time scale for the NS to collapse into the PBH and show that essentially nothing remains behind. As a result, and in contradiction to other claims in the literature, we conclude that thisis an unlikely site for ejecta and nucleosynthesis, at least in spherical symmetry.

Pomahač, Matěj. 2011. Headhunting: etnografie utváření osoby jako zboží. Nepublikovaná diplomová práce. Praha: FHS UK. Key Words ethnography; human resources consulting; headhunting; economic anthropology; economization; commodification; structural holes Summary This thesis is based on more than a year-long research which took place in a private human resources consulting company focused on the search for highly skilled workers (known as headhunting). The research focus was based primarily on the fact, that the author worked in the reference field as human resources consultant. This perspective enabled to focus on description and perception of everyday activities ongoing in the company in relation to its clients and candidates, from the headhunter's point of view. The data collected during the course of participant observation have been analysing with the use of Michel Callon's studies of economization and commodification in major part, and through the Ronald S. Burt's theory of structural holes in minor part. The analysis reveals the economic and political factors determining the field of headhunting practices and procedures, which headhunters use in order to face up their position of intermediary party between clients and candidates. The study also focuses on processes and technologies, by means of the...

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23707号 / 理博第4797号 / 新制||理||1687(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 上田 佳宏, 教授 嶺重 慎, 准教授 岩室 史英 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Primordial black holes (PBHs) are expected to form in the very early universe, and therefore, we could use them to probe pre­BBN times. Astrophysical observations permit the placement of bounds on the abundance of PBHs. Combining these bounds with predictions of PBH formation and the resulting PBH abundances, we explore the possibility to constrain an epoch of early matter domination (MD). For this analysis, we incorporate the recently obtained and most stringent bounds on PBHs from 21 cm observations. We assume density perturbations described by a near­power­law form of the curvature power spectrum consistent with the Planck 2018 results and derive the corresponding PBH mass function using recent results from the literature. To place constraints on an early matter­dominated (MD) epoch, we compare this with up­to­ date bounds on PBHs, adding those from 21 cm astronomy, using a formalism to apply monochromatic constraints to extended mass functions. We find that 21 cm bounds on PBHs may probe early MD if it lasts for a duration of at least ∼ 12 e­folds and ends at a reheating temperature T_min &lt; T_reh ≲ 105.5 GeV, where Tmin depends on the duration of the MD, the spectral index ns, and αs. For optimistic assumptions, our derived limits on the spectral index ns extend into the Planck 2018 67% upper confidence region of n_s = 0.9649 ± 0.0042, nearly reaching its median n_s = 0.9649, if we neglect the running αs. Our bounds on the running α_s show that early MD is incompatible with positive running α_s ≳ 0. / Primordiala svarta hål förutsäges ha skapats i det mycket tidiga universum. Ur detta förstår vi att dessa svarta hål ger oss en länk till universums tillstånd under deras skapelse och att vi genom studiet av primordiala svarta hål kan skymta detta tillstånd. Restriktioner på mängden primordiala svarta hål i universum kan beräknas utifrån astrofysiska observationer. Jämförelse av dessa restriktioner med teoretiska förutsägelser av vilka mängder av primordiala svarta hål som skapats vid olika tillstånd medger att vissa tillstånd utesluts. I detta arbete undersöker vi just detta samband och avser etablera huruvida de starkaste restriktionerna på primordiala svarta hål, speciellt från 21 cm observationer av universum, kan utesluta ett kosmologiskt scenario med tidig materiadominans. För att göra detta antar vi att störningar i den annars homogena energidensiteten kan beskrivas med hjälp av ett nästan­storleksoberoende potenssamband vars form ges av resultat från Planck kollaborationen 2018. Givet denna potenslag beräknar vi en form för de primordiala svarta hålens massdistribution medelst resultat från den vetenskapliga litteraturen. Vi jämför sedan dessa förutsägelser med de senaste mängdrestriktionerna på primordiala svarta hål, inkluderat dem från 21 cm observationer, för att erhålla nya begränsningar på tidig materiadominans. Vi tar i beaktande att massdistributionen av primordiala svarta hål inte är monokromatisk, utan utbredd. Resultatet av denna analys är att tidig materiadominans är inom räckhåll för att uteslutas medelst studier av primordiala svarta hål om perioden av materiadominans är längre än ∼ 12 e­folds och att den slutar vid återuppvärmningstemperaturen T_min &lt; T_reh ≲ 10^5.5 GeV, där Tmin beror på hur länge den tidiga materiadominansen varar, på det spektrala indexet ns och det spektrala indexets derivata αs. För optimistiska antaganden äventyrar dessa restriktioner på materiadominans resultat från Planck kollaborationen 2018 i det att det övre konfidensintervallet på det spektrala indexet n_s = 0.9649 ± 0.0042 är exkluderat, och att förändringen av detta index, α_s, inte kan vara positiv då vi låter storleksordningen minska.

This dissertation explores how dark and light personality traits influence venture performance via mediating effects of social structure. Because entrepreneurship is an inherently social process, theoretical perspectives of social network theory and social comparison theory are used to examine how entrepreneurs’ dark and light personality traits interact with personality traits of socially proximal others to influence venture performance via network structure. These perspectives are drawn together using socioanalytic theory. This dissertation argues that agreeableness and narcissism interact with the personality traits of network others at the group-level to influence structural hole positioning within entrepreneurial networks; in turn, structural holes are hypothesized to exert a positive effect on venture revenue. This study offers contributions to the fields of entrepreneurship, entrepreneurial personality, social networks, and social comparison processes. Hypotheses are tested using a dataset of 234 entrepreneurs nested within 24 groups; analyses are conducted via linear mixed effects models and Monte-Carlo approximation of mediation confidence intervals (Model 1) and OLS regression and non-parametric bootstrapping approximation of mediation confidence intervals (Model 2).