Typ Ia Supernovae (SNe) können verwendet werden, um Bulk-Flows zu messen, die durchschnittliche Bewegung von Materie relativ zur kosmischen Mikrowellenhintergrundstrahlung (CMB). Bulk-Flow-Studien ermöglichen Tests der Behauptung des Kosmologischen Prinzips von Homogenität und Isotropie für ausreichend große Distanzen. Im letzten Jahrzehnt wurden mehrere hohe Bulk-Geschwindigkeiten in großen Skalen gemeldet, die schwer mit den Vorhersagen des ΛCDM-Kosmologiemodells zu vereinbaren sind. In dieser Arbeit schätze ich Bulk-Flows auf der Grundlage einer neuen Probe von SNe aus einer Next-Generation-Sky-Survey namens Zwicky Transient Facility (ZTF). Die Auswahl und Analyse der großen Anzahl von astrophysikalischen Transienten, die jede Nacht von dieser Survey erfasst werden, ist komplex. Ich habe eine flexible Analysis Software namens AMPEL entwickelt, um diese Aufgaben zu erfüllen. Ein neuer ZTF-Datensatz, der aus etwa 850 Typ Ia SNe besteht, wurde für diese Forschung zusammengestellt. Simulationen zeigen, dass die nicht-sphärische Surveygeometrie von ZTF, die aktuellen Stichprobengrößenbeschränkungen und der Malmquist-Bias zusammen systematische Effekte ergeben, die kleiner sind als die aktuellen statistischen Unsicherheiten. Ich habe die ZTF-Probe zusammen mit zwei anderen kosmologischen SNe-Proben im heliozentrischen Inertialsystem verwendet, um das kosmische Ruhesystem unabhängig vom CMB zu etablieren. Der gemessene Beobachter-Dipol innerhalb der Rotverschiebungsschale 0,06 < z < 0,1 zeigt eine Konvergenz mit dem CMB-Temperaturdipol. Im CMB-Inertialsystem im gleichen Skala wird kein signifikanter Bulk-Flow gemessen. / Type Ia supernovae (SNe) can be used to measure bulk flows, the average motion of matter relative to the Cosmic Microwave Background (CMB). Bulk-flow studies enable tests of the Cosmological Principle’s assertion of large-scale homogeneity and isotropy. Over the past decade, several high bulk-velocities at large scales have been reported, which are difficult to unify with constraints from the ΛCDM cosmological model. In this work, I estimate bulk-flows based on a new sample of SNe from a next-generation sky survey called the Zwicky Transient Facility (ZTF). Selecting and analyzing the large number of astrophysical transients detected each night by this survey is complex. I developed a flexible analysis framework called AMPEL to address these challenges. A new ZTF dataset comprising roughly 850 type Ia SNe was assembled for this research. Simulations show that the non-spherical survey geometry of ZTF, the current sample size limitations, and the Malmquist bias together yield systematic effects smaller than current statistical uncertainties. I used the ZTF sample along with two cosmological-grade SNe samples in heliocentric inertial frame to establish the cosmic rest frame independently from the CMB. The measured observer-dipole within the redshift shell 0.06 < z < 0.1 shows convergence with the CMB temperature dipole. In the CMB inertial frame at the same scale, no significant bulk-flow is detected.

Master of Science / Department of Grain Science and Industry / Kingsly Ambrose / Consistent and reliable flow of bulk wheat from hoppers and silos is very significant in wheat handling and processing. Bulk wheat flow challenges such as inconsistent flow, arching, etc., are common during handling. The irregular size and non-uniformity of physical properties, the presence of impurities affects the flow behavior during discharge. Chaff and insects infested kernels are the two most common impurities present in wheat. In this research, the effect of these two impurities on their physical and flow properties of wheat were studied. Physical and flow indicators, such as bulk, tapped, particle densities, angle of repose, Hausner’s ratio, Carr index, and porosity measures the flowability of uncompacted bulk solids. Meanwhile, flow properties tested by shear testing principle based on Jenike’s method, simulated bulk wheat under pressure in bins/hoppers. The dynamic properties tested quantify the energy required to flow, compressibility and permeability at dynamic handling situations. Due to the presence of impurities and moisture content differences, bulk density and angle of repose of wheat varied from 801.54kg/m3 to 718.36kg/m3, and 23.6° to 38.4°, respectively. Angle of internal friction and wall friction angle that reflect interaction between particles and particle with bins/hopper walls, ranged from 23.95° to 43.13° and 15.46° to 20.33°, respectively. In addition to instrumental flow property evaluation, the flow profile, discharge rate, and particle velocity during hopper flow of bulk wheat was studied using Particle Image Velocimetry method. Mass flow and funnel flow hopper dimensions were used for this flow profile analysis. The discharge rate decreased from 1.67 to 1.12 kg/s for mass flow and 1.42 to 0.86 kg/s for funnel flow when the chaff in bulk wheat increased from 0% to 7.5% (weight basis). Analysis of the active flow zone indicated that bulk wheat without chaff had a uniform flow compared to wheat with chaff in the bulk. The findings from this study will be useful for design of hopper bottom bins and handling equipment based on the wheat quality and percent moisture content.

A statistical investigation of the relationship between Lorentz force and Bursty Bulk Flow event (BBF) spatial location in the magnetotail is undertaken. Data is obtained in situ by the ESA Cluster II mission during the period July to October 2004. Firstly, a short introduction to BBFs and the Cluster mission is presented. Secondly, the curlometer method for determining Current densities in the Inner Central Plasma Sheet and its approximations are discussed. The curlometer method uses magnetic field density data from the Fluxgate Magnetometer (FGM) instrument and plasma velocities are obtained by the Hot Ion Analyzer (HIA) instrument. The satellite separation at the time of the measurement in the year 2004 was on the order of 1000 km. Results of the investigation are inconclusive. A few possible sources of error and reference material are mentioned.