On debugging in a parallel system

In this paper a description is given of a partly implemented parallel debugger for the Twente University Multicomputer (TUMULT). The system's basic method for exchange of data is message passing. Experience has learned that most programming errors in application software are made in calls to the kernel and the interprocess communication. The debugger is intended to be used for locating bugs at this level in the application software. It is assumed that basic blocks of the debuggee can be debugged using a traditional sequential sourcelevel debugger

Role of oxides and nano structure of Cu catalysts for the electrochemical reduction of CO₂

The need for clean, energy efficient and environmental friendly technologies to close the resource cycle and help building a sustainable economy is higher than ever. A promising approach to achieve this goal is the utilization of atmospheric CO2 by its electro-catalytic reduction towards non-fossil fuels and chemical resources. Despite numerous dedicated studies carried out in the past decades, detailed understanding of the reaction mechanism and the reaction’s dependence on specific parameters such as the surface orientation and structure on an atomic scale, the chemical environment under which the reaction is carried out, the oxidation state of the employed catalysts or quantum size effects possibly becoming relevant at small length scales, is missing. The scientific work presented here is addressing many of these issues focusing on examining the influence of oxides when running the reaction as well as on the selectivity-structure correlations on an atomic scale. Utilizing various existing ultra high vacuum based techniques together with operando, synchrotron-based, electrochemical experiments and developing new techniques, this work demonstrated for the first time that oxide species are particularly important for the reaction path- way towards multi-carbon chain oxygenate products. Surprisingly, unlike thought, the selectivity towards especially ethylene is independent on the presence of those species. Employing well defined single crystal surfaces it is revealed that structural properties are the key parameter determining the reduction reaction selectivity towards non-oxygenate products. By controlling and characterising such surfaces on the atomic scale this work significantly contributes to the field by further pointing out that the pristine undisturbed crystal orientation of the surface is, unlike believed on the basis of the existing theoretical predictions and experimental data, not as important as the presence of defects in the atomic lattice and high index facets on the surface. Furthermore, those results are put to use and into perspective when analysing the behaviour of high surface area nano-structured catalysts that are also considered for large scale up industrial applications. Using a combination of spectro- scopic and electrochemical techniques the work provides detailed information about the importance of the chemical environment in the catalytic performance and points out new directions to further improve existing catalysts. For instance synergistic effects in bi-metallic nano structured systems are utilized, and the crucial role of the support in determining the reaction outcome explained. Similarly the effects of the electrolyte are explored, showcasing that the performance of already existing highly selective catalysts can be further improved due to an enhanced stability of crucial reaction intermediates on the surface as a consequence of the exposure to certain halides and alkaline cations. These results clearly indicate that structural and morphological properties of catalysts are the key factors in determining the reaction selectivity towards specific products while only the oxygenate selectivity is found to be significantly affected by the chemical state and environment

Diffraction-contrast imaging of cold atoms

We consider the inverse problem of in-line holography, applied to minimally-destructive imaging of cold atom clouds. Absorption imaging near-resonance provides a simple, but destructive measurement of atom column density. Imaging off resonance greatly reduces heating, and sequential images may be taken. Under the conditions required for off-resonant imaging, the generally-intractable inverse problem may be linearized. A minimally-destructive, quantitative and high-resolution image of the atom cloud column density is then retrieved from a single diffraction pattern.Comment: 4 pages, 3 figures v2: minor changes in response to referee reports, mostly additional experimental detail v3: revisions to figure 3: added trace and changed image. Minor text and referencing changes. Accepted by Phys Rev A (Rapid Commun

A Real time network at home

This paper proposes a home network which integrates both real-time and non-real-time capabilities for one coherent, distributed architecture. Such a network is not yet available. Our network will support inexpensive, small appliances as well as more expensive, large appliances. The network is based on a new type of real-time token protocol that uses scheduling to achieve optimal token-routing through the network. Depending on the scheduling algorithm, bandwidth utilisations of 100 percent are possible. Token management, to prevent token-loss or multiple tokens, is essential to support a dynamic, plug-and-play configuration. Small appliances, like sensors, would contain low-cost, embedded processors with limited computing power, which can handle lightweight network protocols. All other operations can be delegated to other appliances that have sufficient resources. This provides a basis for transparency, as it separates controlling and controlled object. Our network will support this. We will show the proposed architecture of such a network and present experiences with and preliminary research of our design

Quasi dynamical symmetry in an interacting boson model phase transition

The oft-observed persistence of symmetry properties in the face of strong symmetry-breaking interactions is examined in the SO(5)-invariant interacting boson model. This model exhibits a transition between two phases associated with U(5) and O(6) symmetries, respectively, as the value of a control parameter progresses from 0 to 1. The remarkable fact is that, for intermediate values of the control parameter, the model states exhibit the characteristics of its closest symmetry limit for all but a relatively narrow transition region that becomes progressively narrower as the particle number of the model increases. This phenomenon is explained in terms of quasi-dynamical symmetry.Comment: 4 figure

Smart Solutions: Smart Grid Demokit

Treball desenvolupat dins el marc del programa 'European Project Semester'.The purpose of this report is to justify the design choices of the smart grid demo kit. Something had to be designed to make a smart grid clear for people who have little knowledge about smart grids. The product had to be appealing and clear for people to understand. And eventually should be usable, for example, on an information market. The first part of the research consisted of looking how to shape the whole system. How the 'tiles' had to look to be interactive for users and what they should feature. One part of this was doing research to get to know more about the already existing knowledge amount users. Another research investigated what appeals the most to the users. After this, a concept was created in compliance with the group and the client. The concept consists of hexagonal tiles, each with a different function: houses, solar panels, wind turbines, factories and energy storages. These tiles are all different parts of a smart grid. When combining these tiles, it can be made clear to users how smart grids work. The tiles are fabricated using a combination of 3D printing and laser cutting. The tiles have laser cut symbols on top of them to show what part of the smart grid they are. Digital LED strips are on top of the tiles to show the direction of the energy flow, and the colors indicate if the tile is producing or consuming power from the grid. The tiles are connected to each other by the so called “grid blocks”. These blocks make up the central power grid and are also lighting up by LED strips. Each tile is equipped with a microcontroller which controls the LED strips and makes it possible for the different tiles to “talk” with each other. Using this, the central tile knows which tiles are connected to the system. The central tile controls all tiles and runs the simulation of the smart grid. For further development of the project, it can be investigated how to control and adjust the system from an external system, for example by a tablet. The final product consists of five tiles connected by seven grid blocks which show how a smart grid works

Quantum phase transitions in Bose-Fermi systems

Quantum phase transitions in a system of N bosons with angular momentum L=0,2 (s,d) and a single fermion with angular momentum j are investigated both classically and quantum mechanically. It is shown that the presence of the odd fermion strongly influences the location and nature of the phase transition, especially the critical value of the control parameter at which the phase transition occurs. Experimental evidence for the U(5)-SU(3) (spherical to axially-deformed) transition in odd-even nuclei is presented.Comment: 38 pages, 29 figure

Harmonizing Software Standards with a Semantic Model

The application of standards in the software development process supports interoperability between systems. Maintenance of standards must be guaranteed on the organisational and technical level. The use of semantic technologies can contribute to the standard maintenance process by providing a harmonizing bridge between standards of different knowledge domains and languages and by providing a single point of administration for standard domain concepts. This paper describes a case study of the creation of a semantic layer between software standards for water management systems in The Netherland

Alternative Interpretation of Sharply Rising E0 Strengths in Transitional Regions

It is shown that strong 0+2 -> 0+1 E0 transitions provide a clear signature of phase transitional behavior in finite nuclei. Calculations using the IBA show that these transition strengths exhibit a dramatic and robust increase in spherical-deformed shape transition regions, that this rise matches well the existing data, that the predictions of these E0 transitions remain large in deformed nuclei, and that these properties are intrinsic to the way that collectivity and deformation develop through the phase transitional region in the model, arising from the specific d-boson coherence in the wave functions, and that they do not necessarily require the explicit mixing of normal and intruder configurations from different IBA spaces.Comment: 6 pages, 3 figure