Application of Microwave Methods for Characterization of NEG Coatings and Obstacle Detection in Accelerator Beam-pipes

In many particle accelerators, including the LHC at the European Organization for Nuclear Research CERN, NEG coatings are used to improve vacuum performance. In other particle accelerators there have been hints that those coatings could have a relevant impact on the beam coupling impedance, however the data available is contradictory. To clarify the possible impact of NEG coatings the electromagnetic properties have been measured. The measurements have been carried out by means of cavity perturbation method. The second part of this thesis deals with the microwave waveguide reflectometer developed at CERN several years ago, which is used as part of the quality assurance test program for the LHC assembly. To ensure optimum operation and to avoid an expensive removal of any foreign object from inside the LHC beam-screen after its completion, microwave reflectometry is performed. Until now several objects have been found by means of reflectometry, but so far neither precise data about the reflections of different foreign objects, nor the precise limits of the system are known

Behavioural postures and the rate of body temperature change in wild freshwater crocodiles, Crocodylus johnstoni

I recorded body temperature and behaviour of eight Crocodylus johnstoni in the wild over a 2-yr period in order to quantify the effect of posturing on body temperature and to provide a mechanistic explanation of how behaviour affects body temperature. Behaviour was categorised according to the proportion of a crocodile's surface area exposed from the water (0% exposed [=diving] to 100% exposed [=basking]). Crocodiles did not simply shuttle between the extremes of 100% exposed and diving but showed an array of intermediate postures. Rates of body temperature change were negative for exposures less than 40% and positive for 60%-100% exposed. This was due to the difference between operative temperature and body temperature, which was negative during diving but increased with the percentage of exposure, up to 25 degrees-30 degrees C during basking. For any particular posture, the rate of body temperature change decreased with increasing mass. Thermal time constants were shortest during diving and longest during basking. A heat-transfer equation predicted the rate of body temperature change well, except that it underestimated the rate of body temperature change during 80% and 100% exposed. Exposing only a small part of their body when in water (20%) slowed heat loss considerably, allowing crocodiles to spend more time in the water while maintaining body temperature within their preferred body temperature range

AN EXAMINATION OF A CONDUCTOR’S PERFORMANCE PREPARATION OF THE MENDELSSOHN VIOLIN CONCERTO IN E MINOR

The music of Felix Mendelssohn-Bartholdy (1809-47) has earned a prominent position in the orchestral repertoire. One of his greatest works, and certainly one of the most performed, is his Violin Concerto in E minor, Op. 64. The work enjoys much popularity with, and recognition by, soloists, orchestras, and conductors alike. Even with its fame and familiarity, it remains a work that must be carefully studied and prepared by the conductor. This document presents an examination of a conductor’s performance preparation of the Mendelssohn Violin Concerto. The purpose of this examination is to equip the conductor with a depth of knowledge that will yield rehearsals and performances of the concerto that are stylistically appropriate, well informed, and efficient. Major sections include an examination of the concerto’s 1844 and 1845 versions and available performance materials, tempo selection and execution, size, balance and composition of the orchestra, stylistic traits, and aspects of performance practice

Motion control using optical flow of sparse image features

Reactive motion planning and local navigation of robots remains a significant challenge in the motion control of robotic vehicles. This thesis presents new results on vision guided navigation using optical flow. By detecting key image features, calculating optical flow and leveraging time-to-transit (tau) as a feedback signal, control architectures can steer a vehicle so as to avoid obstacles while simultaneously using them as navigation beacons. Averaging and balancing tau over multiple image features successfully guides a vehicle along a corridor while avoiding looming objects in the periphery. In addition, the averaging strategy deemphasizes noise associated with rotationally induced flow fields, mitigating risks of positive feedback akin to the Larsen effect. A recently developed, biologically inspired, binary-key point description algorithm, FReaK, offers process speed-ups that make vision-based feedback signals achievable. A Parrot ARDrone2 has proven to be a reliable platform for testing the architecture and has demonstrated the control law's effectiveness in using time-to-transit calculations for real-time navigation

A Model-driven Approach for the Description of Blockchain Business Networks

The concept of blockchain technology has gained significant momentum in practice and research in the past few years, as it provides an effective way for addressing the issues of anonymity and traceability in distributed scenarios with multiple parties, which have to exchange information and want to securely collaborate with each other. However, up-to-date, the impact of the structure and setup of business networks on successfully applying blockchain technology, remains largely unexplored. We propose a model-driven approach, combining an ontology and a layer model, that is capable of capturing the properties of existing blockchain-driven business networks. The layers are used to facilitate the comprehensive description of such networks. We also introduce the Blockchain Business Network Ontology (BBO), formalizing the concepts and properties for describing the integral parts of a blockchain network. We show the practical applicability of our work by evaluating and applying it to an available blockchain use case

Increased physical activity does not improve obesity-induced decreases in muscle quality in zebrafish (Danio rerio)

Obesity has a negative effect on muscle contractile function, and the effects of obesity are not reversed by weight loss. It is therefore important to determine how muscle function can be restored, and exercise is the most promising approach. We tested the hypothesis (in zebrafish, Danio rerio) that moderate aerobic exercise (forced swimming for 30 min per day, raising metabolic rates to at least twice resting levels) will alleviate the negative effects of obesity of muscle function. We allocated zebrafish randomly to experimental treatments in a fully factorial design with diet treatment (three levels: lean control, diet-induced obese, obese followed by weigh loss [obese-lean]), and exercise (exercise and sedentary control) as independent factors. Treatments were conducted for 10 weeks, and we measured locomotor performance, isolated muscle mechanics, and myosin heavy chain composition. Obesity led to decreased muscle force production per unit area (p = 0.01), and slowed muscle contraction (p = 0.004) and relaxation rates (p = 0.02). These effects were not reversible by weight loss or exercise. However, at the level implemented in our experimental animals, neither diet nor exercise affected swimming performance or myosin heavy chain concentrations. The moderate levels of exercise we implemented therefore are not sufficient to reverse the effects of obesity on muscle function, and higher intensity or a combination of modes of exercise may be necessary to improve muscle quality during obesity and following weight loss.Funding provided by: Australian Research CouncilCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000923Award Number: DP18010303