Modern cranes built for the handling of containers should work efficiently concerning the energy consumption, and should also decrease the time of the handling process by using high trolley velocities. On the other hand these cranes should be able to reach the target positions precisely and without residual vibrations. Especially, the trolley accelerations needed to shorten the operating cycles excite the load as well as the crane structure, leading to vibrations, which should be reduced by suitable control methods. This Dissertation develops energy and time optimal control methods on the basis of suitable models of container handling systems for transferring a load unit. Based on the Pontryagin maximum principle the optimal control methods are determined. Their disadvantage, however, is that they react very sensitively on the inaccuracies of the system parameters. Especially, the data of the containers is very often not known exactly. That is why the input shaping method is taken as an alternative to the optimal solution based on the maximum principle. The corresponding suboptimal solutions are very robust concerning the inaccuracies of the system parameters and the initial conditions. The mechanical modelling takes into account the pendulum like motion of the load as well as the vibration of the crane structure.

This work analyses the operating performance of polymer-electrolyte-membrane fuel cells (PEMFC) for the use as portable energy converter. Especially, mass transport in the liquid and gaseous phase inside the PEMFC are experimentally examined. Water produced during the reaction is measured and liquid water transport in the air flow field of a semi-transparent PEMFC is visualized. Besides this, investigations of different flow field designs are used to develop two portable PEMFC systems. To understand the physical and electrochemical behaviour inside a PEMFC numerical simulations are performed. The used mathematical model is provided by the company Fluent. It verifies spatially resolved current distribution measurements of a PEMFC with straight, parallel gas channels. Thereby, the calculations can be used for the optimisation of the operating performance of PEMFC systems.

Theoretical models describing the kinetic and evaporation as well as the electrical charge of droplets in a droplet chain generated by a vibrating orifice generator are presented. The models are verified by experimental results. Droplet charge and the electrical current transported by the droplet chain are correlated with the length of the liquid jet. Based on these results, an apparatus for generating neutral or predefined charged particles has been developed, whereby not only the average charge of the particle collective, but also the charge of individual droplets can be defined. The applicability in generating solid particle aerosols by jet dispersion of solutions are disclosed.

The present work discusses the applications of e-learning offers, that are targeted on enhancing engineering laboratory courses in their preparation, processing and postprocessing phases. In the context of higher education at university level, different approaches on designing a didactical framework are presented. As a result a teaching and learning model is proposed, where real laboratory parts and virtual trainings are combined to hybrid learning arrangements.

This research investigates the environment impacts of hospital waste pretreatment residues under landfill conditions. Two techniques - incineration and sterilization - to treat hospital waste were taken into concern. The biodegradability of sterilized hospital waste and leaching behavior of hospital waste incineration ash were investigated, as well as co-dispoal hospital waste pretreatment residues with municipal solid waste. With the research results, a novel approach to treat hospital waste pretreatment residues were concluded.

Thesis--University of London, 1991. / Bibliogr. p. 147-168.

Today's wireless transceivers require reference signals to translate received and transmitted signals to their desired frequencies. Therefore, they need frequency synthesizers which are typically based on phase-locked-loops (PLLs). Communication standards like GSM or Bluetooth necessiate that the PLLs put out oscillations with high spectral purity and accuracy. Additionally, the oscillation frequency must be adjustable very accurately at low transient time to account for occasional carrier frequency changes. So called Sigma-Delta-fractional-N frequency synthesizers are often employed to fulfil these requirements. However, the number and the locations of the poles of the control loop and hence the loop filter must be chosen properly. Unity gain frequency and phase margin have to be considered as well as the stringent frequency accuracy and the detailed origin of the spurious emissions. The design methodology proposed in this work is based on numerical optimization techniques, a high number of control loop poles and the use of Gm-C-biquads as loop filter building blocks.

Zugl.: Trier, Univ., Diss., 2007

Zugl.: Bochum, Univ., Diss., 2006

Industrial society has changed thoroughly during the last half a century. In many Western cities and towns, new patterns of production and consumption entailed that centrally located industrial areas became redundant. The once lively workplace and urban core became silent and abandoned, gradually falling into decay. In recent decades, the former industrial built environment was reinterpreted and reused as apartments, offices, heritage sites, stages for artistic installations and destinations for cultural tourism. Companies and former workers, heritage and planning professionals, as well as artists and urban explorers, were some of the actors involved in the process. The overall aim of the study is to contribute to an understanding of this transformation, and hence it addresses questions about what happened to the industrial places that lost their original function and significance. How were they understood and used? Who engaged in their future? What were the visions and what was achieved? Three former industrial areas are examined from a historic perspective and with a critical hermeneutic approach: Koppardalen in Avesta, Sweden, the Ironbridge Gorge Museum in Britain, and Landschaftspark Duisburg-Nord in the Ruhr district of Germany. Included in the results that challenge previous research, the study claims that the key figures were often newcomers to the place, and white-collar professionals, rather than former workers asserting a historic perspective from below on the basis of a crisis experience. In general, the study shows how the redundant industrial place became an arena for visions of the future in a local community, and, furthermore, how it was being turned into a commodity in a complex gentrification process. The place was given new value by being regarded as an expression of the overall phenomenon of reused industrial buildings, and, simultaneously, as a unique and authentic entity. In the conversion of the physical environment, the industrial past became relatively harmless to many people, because the dark and difficult aspects were defused in different ways. Instead, the industrial place was understood in terms of adventure, beauty and spectacle, which included rust from the past as well as hope for the future. / QC 20100910