Hadronic multiparticle production with Sibyll

An updated version of the hadronic interaction model Sibyll is presented. The model focuses on aspects important for cosmic ray interactions. The effect of the model extension on the interpretation of measurements are discussed

Thermal transport of nanoenergetics in composite materials

Field of study: Mechanical and aerospace engineering.Dr. Matthew Maschmann, Thesis Supervisor."December 2017."Nanoenergetic materials such as nanothermites are made up of a mixture of nanoscale fuel and oxidizer particles separated by small distances to promote rapid reaction. When reacted, they can reach an adiabatic flame temperature approximately 3000 to 4000K and generate a shock wave of approximately 2500 m/s. In this work we studied the effects of plasmonic photothermal heating and its interaction with aluminum nanoparticles. Plasmonic gratings are known to enhance electric fields based on the structure and surface plasmon resonance as a result of light coupling. By understanding the effects of enhanced electric fields caused by plasmonic gratings, we can study the effects it has on nanoparticles and its applications in in - situ temperature mapping. From the results of this investigation via numerical methods, it was found that six nanoparticles in contact were enough to reach beyond ignition temperature of 470 degrees C, and validated the plasmonic grating does enhance the photothermal heating of nanoparticles. Another facet to this thesis is the investigation of thermal conductivity of graphene with decorated aluminum nanoparticles. Graphene acts as a great platform for spreading thermal energy due to its excellent thermal properties. We investigate the potentially beneficial thermal properties for sustaining combustion during nanoparticle heating. However, the phonon scattering caused by nanoparticles on the surface of graphene is still not completely understood. This work gives preliminary simulation results and experimental designs to the investigation of the thermal conductivity of graphene with decorated nanoparticles.Includes bibliographical references (pages 82-85)

Effectiveness of Autism Education in Accredited Dental Hygiene Programs

The increase in the prevalence of individuals diagnosed with autism spectrum disorder (ASD) has increased dramatically over the last few decades, causing an increase in the exposure of dental professionals to patients with the disorder in a clinical setting. The purpose of this study is to understand the influence of the licensed dental hygienists’ professional attitude towards treating a patient with ASD, and the level of accommodations provided to patients with ASD during a routine dental visit, based on the amount of knowledge provided about the disorder during an accredited dental hygiene program. Survey data were collected from 78 registered dental hygienists from the states of Kentucky and Tennessee. The results revealed that 58 (80.5%) treat patients with ASD within their dental practices, and 41.03% of these reported treating one patient per month. The researcher sought to investigate the influence of the amount of knowledge presented on ASD within an accredited dental hygiene program and the influence of the dental hygienists’ attitude towards treating patients with ASD post-graduation. Results of the study revealed no significant difference of the dental hygienists’ professional attitude toward treating a patient with autism spectrum disorder and the accommodations provided to patients with autism during a routine dental visit and the amount of education provided during their accredited dental hygiene program. Given the increased prevalence of ASD, it is vital to address the lack of access to care, and evaluate the amount of education received while attending an accredited dental hygiene program

Calculation of conventional and prompt lepton fluxes at very high energy

An efficient method for calculating inclusive conventional and prompt atmospheric leptons fluxes is presented. The coupled cascade equations are solved numerically by formulating them as matrix equation. The presented approach is very flexible and allows the use of different hadronic interaction models, realistic parametrizations of the primary cosmic-ray flux and the Earth's atmosphere, and a detailed treatment of particle interactions and decays. The power of the developed method is illustrated by calculating lepton flux predictions for a number of different scenarios.Comment: 8 pages, 10 figures, for Proceedings of the International Symposium for Very-High Energy Cosmic-Ray Interactions (ISVHECRI 2014

Molekulare Gymnastik : Rotationen, Schwingungen und chemische Reaktionen

Bei jeder chemischen Reaktion werden Bindungen gebrochen und andere neu geknüpft. Dabei ändert sich die Anordnung und eventuell Anzahl der Atome im Molekül. Voraussetzung hierfür sind Bewegungen der beteiligten Atome und Moleküle. Um chemische Umwandlungen in "Echtzeit" zu studieren, müssen Untersuchungen im Zeitbereich der Schwingungs- und Rotationsdynamik durchgeführt werden. Dazu nutzen Wissenschaftler des Instituts für Physikalische und Theoretische Chemie die Möglichkeiten der modernen Ultrakurzzeit-Lasertechnik

The hadronic interaction model SIBYLL 2.3c and Feynman scaling

The Monte Carlo model Sibyll has been designed for efficient simulation of hadronic multiparticle production up to the highest energies as needed for interpreting cosmic ray measurements. For more than 15 years, version 2.1 of Sibyll has been one of the standard models for air shower simulation. Motivated by data of LHC and fixed-target experiments and a better understanding of the phenomenology of hadronic interactions, we have developed an improved version of this model, version 2.3, which has been released in 2016. In this contribution we present a revised version of this model, called Sibyll 2.3c, that is further improved by adjusting particle production spectra to match the expectation of Feynman scaling in the fragmentation region. After a brief introduction to the changes implemented in Sibyll 2.3 and 2.3c with respect to Sibyll 2.1, the current predictions of the model for the depth of shower maximum, the number of muons at ground, and the energy spectrum of muons in extensive air showers are presented.Comment: 35th International Cosmic Ray Conferenc

Universality of the muon component of extensive air showers

In extensive air shower experiments, the number of muons crossing a detector at a given position, as well as their arrival time, arrival direction, and energy, are determined by a more fundamental 3-dimensional distribution linked to the hadronic core of the shower. Muons are produced high up in the atmosphere after the decay of mesons in the hadronic cascade. The distributions of production depth, energy, and transverse momentum of muons are enough to fully predict the muon component of air showers in any particular observational condition. By using air-shower simulations with the state-of-the-art hadronic interaction models, the mentioned distributions at production are analyzed as a function of zenith angle, primary mass, and hadronic interaction model, and their level of universality is studied and assessed in an exhaustive manner for the first time