Design and construction of a scintillating fibre tracker for measuring hard exclusive reactions at HERMES

This thesis describes design and construction of the SFT. The first section gives a comprehensive overview of the experimental set-up of HERMES and its components relevant for DVCS analysis. The second section introduces the Recoil Detector and Monte Carlo (MC) studies performed to evaluate the requirements for the individual detector parts. In the third section a detailed description of the design parameters and constraints is given and the chosen materials and assembling methods are discussed. This section is complemented by reporting results of the performance of SFT prototype modules from a test experiment conducted at GSI. Finally, an introduction into the GPD formalism and its application to nuclei is given in the fourth section and pioneering results of DVCS off nuclei are presented in the fifth section.Im Rahmen dieser Arbeit wird die Planung und der Bau eines Spurrekonstruktionsdetektors aus szintillierenden Fasern (SFT) für den HERMES Recoil-Detektor beschrieben. Dies umfaßt die Festlegung der Entwurfsziele, Entwicklung von Herstellungverfahren, Auswahl der Detektorbestandteile sowie die Durchführung und Auswertung von Komponententests. Abschließend wird eine Einführung in den Generalised Parton Distribution-Formalismus (GPD) zur Beschreibung der nicht-perturbativen Nukleonstruktur gegeben. Dieser Formalismus kann auch auf Atomkerne angewendet werden und zu neuen Einsichten in die Kernstruktur und partonische Freiheitsgrade im Kern führen. Anschließend wird die Analyse tief-virtueller Compton-Streuereignisse an verschiedenen Kernen beschrieben

A NOVEL BCG SENSOR-ARRAY FOR UNOBTRUSIVE CARDIAC MONITORING

Unobtrusive heart rate monitoring is a popular research topic in biomedical engineering. The reason is that convential methods, e.g. the clinical gold standard electrocardiography, require conductive contact to the human body. Other methods such as ballistocardiography try to record these vital signs without electrodes that are attached to the body. So far, these systems cannot replace routine procedures. Most systems have some drawbacks that cannot be compensated, such as aging of the sensor materials or movement artifacts. In addition, the signal form differs greatly from an ECG, which is an electrical signal. The ballistocardiogram has a mechanical source, which makes it harder to evaluate. We have developed a new sensor array made of near-IR-LEDs to record BCGs. IR-sensors do not age in relevant time scales. Analog filtering was neccesary, because the signal amplitude was very small. The digitized data was then processed by various algorithms to extract beat-to-beat or breath-to-breath intervals. The redundancy of multiple BCG channels was used to provide a robust estimation of beat-to-beat intervals and heart rate. We installed the system beneath a mattress topper of a hospital bed, but any other bed would have been sufficient. The validation of this measurement system shows that it is well suited for BCG recordings. The use of multiple channels has proven to be superior to relying on a single BCG channel

Thermoschockverhalten und temperaturabhängige Eigenschaften kohlenstoffarmer und -freier Feuerfestwerkstoffe

Novel developed refractories with reduced carbon content for application in steel industry were investigated regarding to their thermo-mechanical behaviour. Another major part of this work was focused on the development and trial of new/optimization of established test methods (thermal shock by heating via electron beam and wedge splitting test). Al$_{2}$O$_{3}$ with the addition of 2.5 wt.% ZrO$_{2}$ and TiO$_{2}$ respectively (AZT) leads to animproved thermal shock behaviour compared to pure Al$_{2}$O$_{3}$ materials. Temperature dependent investigations revealed a thermal hysteresis of elastic modulus, shear modulus, Poisson's ratio and thermal expansion, accompanied by a phase transformation of ZrO$_{2}$ (monoclinic $\rightarrow$ tetragonal). High temperature (800 - 1000 $^{\circ}$C) wedge splitting tests were performed with optical notch opening determination for Al$_{2}$O$_{3}$ and AZT. The phase transformation of ZrO$_{2}$ leads to a more brittle behaviour of AZT at 800 $^{\circ}$C compared to room temperature. Different loading configurations for the wedge splitting test were tested using Alumina and Al$_{2}$O$_{3}$-C materials in order to apply the test method on small specimen geometries (40 X 40 X 20 mm$^{3}$). Promising results were obtained from a simple approach using two rollers into a grooved sample. With this method, it was possible to determine a constant (sample material independent) friction coefficent ($\mu$ = 0,13). The results showed a good agreement with experimental data obtained from compact tension tests. Thermal shock tests by heating using the electron beam facility JUDITH 1 allowed the application of a well distributed loading pattern on MgO-C Materials. Temperatures up to 1400 $^{\circ}$C at the surface were achieved. The main damage was observed within the MgO grains

Electrochemical Disinfection of Experimentally Infected Teeth by Boron-Doped Diamond Electrode Treatment

Disinfection and prevention of re-infection are the decisive treatment steps in endodontic therapy. In this study, boron-doped diamond (BDD) electrodes have been fabricated and used for disinfecting the root canals of extracted human teeth, which had been covered with bacterial biofilms formed by Bacillus subtilis and Staphylococcus epidermidis. The growth of B. subtilis could be successfully impaired, achieving a complete disinfection after 8.5 min treatment time with the success of disinfection depending on the insertion depth of the electrode in the root canal. S. epidermidis could completely be removed after 3.5 min treatment time. A clinically applicable electrode array led to complete disinfection after treatment times of 10 min for S. epidermidis and 25 min for B. subtilis. BDD electrode application allowed for the improved disinfection of root canals and dentin tubules based on a continuous production of reactive oxygen species and their enhanced penetration of dentin tubules most likely due the formation of a continuous stream of small gas bubbles. The treatment times that are required here will be shortened in clinical application, as mechanical shaping of the canal system would precede the disinfection process

Evaluation of temporomandibular joints after orthognathic surgery – the anamnestic and clinical index according to Helkimo

Introduction. Skeletal disorders require orthodontic preparation as part of the process of combined surgical and orthodontic treatment planning. The displacement of condylar head to glenoid fossa or to the articulating disc as well as changes in the muscular function can occur as a result of the treatment of morphological disorders. Such displacements and rotations of the condylar long axis can lead to temporomandibular dysfunction. Aim. The purpose of the study was to assess the influence of orthognathic surgery on the temporomandibular function on the basis of the anamnestic and clinical dysfunction index according to Helkimo performed before and after surgical treatment of mandibular prognathism. Material and methods. The material included 20 patients with diagnosed skeletal class III malocclusion. The following examinations were conducted in all patients prior to and 3–6 months after the orthognathic surgery: a subjective examination – anamnesis including the anamnestic index according to Helkimo (Ai); and an objective examination – examination chart and clinical dysfunction index according to Helkimo (Di). Results. The number of individuals without subjective masticatory dysfunction symptoms (anamnestic index according to Helkimo) significantly increased to 14 after the surgery. However, the evaluation of moderate and severe subjective symptoms in the studied group showed no statistically significant changes before and after the operation. Mild symptoms (Di-I) of the clinical dysfunction index according to Helkimo were the most frequent in patients before and after surgical treatment. The number of patients with moderate symptoms (Di-II) decreased after the operation. Conclusions. The clinical dysfunction index according to Helkimo cannot be assessed on the basis of the anamnestic index

A design concept of active cooling for tailored forming workpieces during induction heating

The demand for lightweight construction is constantly increasing. One approach to meet this challenge is the development of hybrid components made of dissimilar materials. The use of the hybrid construction method for bulk components has a high potential for weight reduction and increased functionality. However, forming workpieces consisting of dissimilar materials requires specific temperature profiles for achieving sufficient formability. This paper deals with the development of a specific heating and cooling strategy to generate an inhomogeneous temperature distribution in hybrid workpieces. Firstly, the heating process boundaries with regard to temperature parameters required for a successful forming are experimentally defined. Secondly, a design based on the obtained cooling strategy is developed. Next a modelling embedded within an electro-thermal framework provides the basis for a numerical determination of admissible cooling rates to fulfil the temperature constraint. Here, the authors illustrate an algorithmic approach for the optimisation of cooling parameters towards an effective minimum, required for applicable forming processes of tailored forming

Engaging a product-focused sales force in solution selling: interplay of individual- and organizational-level conditions

This study explains how manufacturers tackle the critical managerial challenge of transforming a product-focused sales force to undertake solution selling. Through an application of configurational theory, the authors explain how individual and organizational conditions combine to determine salespeople’s engagement in solution selling.Multilevel, multisource data from the sales organization of a global supplier of building solutions represent input from salespeople (N = 184), solution champions (N = 23), and sales managers (N = 26). A fuzzy set qualitative comparative analysis reveals no single, optimal way to overcome transformation challenges. Rather, consistent with prior research, solution selling requires certain types of salespeople, because valuebased selling is a necessary condition for successful engagement. Beyond this foundational condition, a heterogeneous sales force can be engaged, as long as the organization provides appropriate support that is tailored to individual salespersons’ needs. The findings affirm that this viable support can come from either sales managers or solution champions.</p