Diss.--Wuppertal, 1996. / Bibliogr. p. 325-349. Index.

Physical inactivity increases the risk of multiple diseases with extensive personal and societal effects [1]. For instance, the annual economic cost of physical inactivity is estimated to be more than 80 billion euros in the European Union (EU) [2]. One measure to increase physical activity is the promotion of active transport modes, such as cycling. Finland is aiming to increase the mode share of active transport modes to 35-38% by 2030 [3]. In tbe most recent national travel survey 8% of daily trips were made by bicycle and 22% of daily trips involved walking [ 4]. A shift from cars to more sustainable transport modes is desirable, however more work is needed to promote cycling safety, with cyclists over-represented in fatal (11%) and serious injuries (32%) when compared to mode share [5]. Amongst cyclist crashes in Finland, single-bicycle crashes (SBCs), where other road users are not collided with, represent more than half of non-fatal injuries [6-7] and 46% of fatal injuries [8--9]. This proportion of non-fatal injuries is similar to findings from other jurisdictions [6]. However, the rate of fatal injuries in SBCs is substantially higher in Finland compared to the average rate in Europe [10], highlighting the importance of understanding SBCs in a Finnish context. Analyses of SBCs are usually more challenging than crashes between bicycles and motor vehicles because SBCs are typically underreported in police-reported crash data [11]. However, in Finland, road crash investigation teams investigate almost all fatal road crashes, including SBCs. This captures high-quality information on SBCs including their contributory and background risk factors, as well as safety recommendations. Identifying the contributory factors that enable the occurrence of crashes and implementing actions to prevent these crashes can help promote cycling safety [ 12]. Such analyses and actions are particularly needed in Finland, where there are targets to increase the mode share of cycling. Given the robust data available through the in-depth investigations undertaken in Finland, this study aims to increase knowledge on SBCs and their safety recommendations by analysing data on fatal cycling crashes in Finland. The study compares the key characteristics, risk factors and safety recommendations regarding SBCs and other cyclist crashes. Although the data for this study is sourced from Finland, the findings are useful in other countries with similar bicycle infrastructure and weather conditions. [From: Introduction]

In our experience of teaching Calculus to engineering undergraduates we have had to grapple with many different problems. A major hurdle has been students’ inability to appreciate the importance of the theory. In their view the theoretical part of mathematics is separate from the computing part. In general, students also believe that they can pass their exams even though they do not have a real understanding of the theory behind the problems they are required to solve. In an effort to surmount these difficulties we tried to find ways to make students better understand the theoretical part of Calculus. This paper describes our experience of teaching Calculus. It reports on the continuation of our previous research.

When specimens of different sands are produced using the same preparation method and sheared under the same conditions (consolidation stress, loading, etc.), while simultaneously keeping the drainage closed, the resulting tendencies of these sands regarding the PWP build-up will be different. This research paper presents a simplified cyclic shear test, which is used to evaluate the accumulation of PWP in sands under defined specimen preparation procedure and testing conditions. In the proposed experiment, a comparison of different sands with this respect is easily achieved. The principle of this experimental method is based on the evolution of the PWP during cyclic shearing of a water-saturated sand sample. Undrained conditions during the experiment allow for the evolution of the PWP, which is quantified by the rate of the PWP build-up. The duration of a single cyclic shear test, including specimen preparation, is approximately 30 min. The evaluation of the rate of the PWP build-up for different densities resulted in an exponential dependence of the PWP build-up on the variation of the relative density. The results confirmed a higher generation of PWP in a fine sand compared to a coarse sand. A comparison with the results of undrained cyclic triaxial tests in the case of eight different sands demonstrated a good agreement between both experimental methods. The basis for the comparison was the density-dependent evolution of PWP in these methods. The presented method delivers a value (index) that quantifies the PWP build-up in sands under the defined testing conditions.

Helmholtz Zentrum Berlin (HZB) baut seit 2011 eine Testanlage Energy Recovery Linac (ERL) Project – BERLinPro. Das Ziel dieses Projektes ist den hohen Strom und hohe Brillanz von dem Elektronenstrahl in einem ERL zu demonstrieren. Die angestrebten Strahlparameter sind vergleichbar mit den Parametern von e.g. zukünftigen ERL-basierten Lichtquellen. Eine von solchen Anlagen ist Femto-Science Factory (FSF), die am HZB konzipiert wurde. FSF ist eine Lichtquelle in Röntgenbereich auf Basis von einem mehrumläufigen ERL mit zweistüfiger Injektion und Energie von einigen GeV. Die Quelle soll Diffraktionslimitiert sein und kurze (Femtosekundenbereich) Lichtpulse erzeugen. Die durchschnittliche und spitzen- Brillanz soll mindesten eine Größenordnung höher liegen als die Brillanz der modernen Speicherring-basierten Lichtquellen. Ein Überblick von BERLinPro und FSF ist gegeben. Eine potentielle Schwäche von ERL besteht in Strahlinstabilitäten, insbesondere regenerative Beam Break Up (BBU). Die Instabilität kann den erreichbaren durchschnittlichen Strom in einem ERL begrenzen. Der Grenzstrom von der BBU für BERLinPro ist berechnet in der Dissertation. Vergleich von zwei Linacs mit zwei verschiedenen supraleitenden Kavitätendesigns ist vorgestellt. Drei Methoden für Strahlstabilisierung (Einfluss von Strahlrotation mit einem Soleniod, Pseudoreflektor, und Tripleten von Quadrupolen in dem Linac auf den Grenzstrom) sind untersucht. Analytische Lösungen für die Twiss-Parameter wurden gefunden für die beste Linacoptik mit und ohne zusätzliche optische Elemente. Zukünftige große ERLs können unterschiedliche Beschleunigungsschemen benutzen. Diese Dissertation vergleicht drei Schemas: unmittelbare Injektion in einen 6 GeV Linac; zweistufige Injektion in einen 6 GeV Linac; und zweistufige Injektion in einen mehrumläufigen Beschleuniger mit geteiltem Hauptlinac in zwei 1 GeV Linacs. Der Basis für den Vergleich ist die Vollkostenanalyse sowie erreichbarer Grenzstrom von den Instabilitäten. / In January 2011 Helmholtz-Zentrum Berlin officially started the realization of the Berlin Energy Recovery Linac (ERL) Project – BERLinPro. The goal of this compact ERL is to develop the accelerator physics and technology required to accelerate a high-current (100 mA) low emittance beam. The parameters are desired for future large scale facilities based on ERLs, e.g. ERL-based synchrotron light sources. One of such large scale facilities is in the design phase at Helmholtz-Zentrum Berlin. This facility is called Femto-Science Factory (FSF). It is a GeV-scale multi-turn ERL-based light source. This light source will operate in the diffraction limited regime for X-rays and offer a short length of a light pulse in the femtosecond region. The average and peak brightness will be at least an order of magnitude higher than achievable from storage rings. In this work an overview of these two projects is given. One potential weakness of the Energy Recovery Linacs is a regenerative form of BBU – transverse beam break up instability. This instability can limit a beam current. In this work the threshold current of the BBU instability was calculated for BERLinPro. The comparison of two linacs based on different types of superconducting cavities is made. Different methods of BBU suppression are investigated (e.g. the influence of solenoid, pseudo-reflector and quadruple triplets in the linac structure on the BBU threshold). Analytic solutions of the Twiss parameters are used to find the best optic in the linac with and without external focusing are presented. Large scale ERL facilities can be realized on different schemes of beam acceleration. This dissertation compares a direct injection scheme with acceleration in a 6 GeV linac, a two-stage injection with acceleration in a 6 GeV linac and a multi-turn (3-turn) scheme with a two-stage injection and two main 1 GeV linacs. The key points of the comparison were total costs and BBU instability. Linac optic solutions are presented.

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In our experience of teaching Calculus to engineering undergraduates we have had to grapple with many different problems. A major hurdle has been students’ inability to appreciate the importance of the theory. In their view the theoretical part of mathematics is separate from the computing part. In general, students also believe that they can pass their exams even though they do not have a real understanding of the theory behind the problems they are required to solve. In an effort to surmount these difficulties we tried to find ways to make students better understand the theoretical part of Calculus. This paper describes our experience of teaching Calculus. It reports on the continuation of our previous research.