New Data Acquisition and Triggering Systems for the DECOR Coordinate Detector

AbstractThe description of the new data acquisition and triggering systems for the DECOR coordinate-tracking detector is presented. The hardware of the DECOR supermodule controller providing effective triggering events of various classes, their readout and transmission to the central computer of the detector was designed and manufactured. The description of the structural solutions used in the design is presented. The results of comparing of the performance of the old and new systems are discussed

Size-dependent bandgap and particle size distribution of colloidal semiconductor nanocrystals

A new analytical expression for the size-dependent bandgap of colloidal semiconductor nanocrystals is proposed within the framework of the finite-depth square-well effective mass approximation in order to provide a quantitative description of the quantum confinement effect. This allows one to convert optical spectroscopic data (photoluminescence spectrum and absorbance edge) into accurate estimates for the particle size distributions of colloidal systems even if the traditional effective mass model is expected to fail, which occurs typically for very small particles belonging to the so-called strong confinement limit. By applying the reported theoretical methodologies to CdTe nanocrystals synthesized through wet chemical routes, size distributions are inferred and compared directly to those obtained from atomic force microscopy and transmission electron microscopy. This analysis can be used as a complementary tool for the characterization of nanocrystal samples of many other systems such as the II-VI and III-V semiconductor materials.Comment: 9 pages, 5 figure

Test Bench Characterisation and Frequency Domain Torsional Model Validation of Transmission Systems and Components

The article presents an experimental methodology used to characterize the torsional dynamic behaviour of automotive transmission systems and components and the analytical methods for simulating them in the frequency domain. A general description of the test bench is given in the paper: it is composed of an induction motor for the torsional excitation of the system and of torque and angular position sensors. The tests were carried out by keeping one end of the transmission locked. Two case study are discussed: a Dual Mass Flywheel (DMF) and a complete Automated Manual Transmission (AMT). In the first example the experimental data from sine sweep tests are used to estimate the damping factor of the DMF. In the second case the dependency of the frequency response function (FRF) on the engaged gear ratio for a 5-speed AMT is investigated. A torsional model for each test rig configuration is proposed and the corresponding equations of motion derived. The compliance FRFs of the torsional systems are then numerically evaluated and compared with the results from the experiments. A good match between simulated and measured data is shown

Design and Characterization of an Affordable Laser Communication System

Over the last decades, an exponential growth in communication demand has been observed. Radio Frequency (RF) band has been one of the most used bandwidths for data transmission in the world. Given the influence and the continuous growth of communication technology, the RF spectrum is overpopulated. More efficient systems are necessary to meet the communication needs of this generation. A change to optical bandwidth is the most practical alternative to deal with the congestion of radio frequency. The aim of this thesis is to present the features of Free Space Optical links with off-the-shelf components. A description of how these systems can apply to satellite communication is given. A theoretical background of the history of optical communications will be provided followed by a gander at the fundamental properties of FSO mechanisms. The thesis will conclude with a detailed description of the choice of hardware utilized, results, and future work

Typification of Incorrect Event Data in Supply Chain Event Management

Due to shorter product life cycles and the increasing internationalization of competition, companies are confronted with increasing complexity in supply chain management. Event-based systems are used to reduce this complexity and to support employees' decisions. Such event-based systems include tracking & tracing systems on the one hand and supply chain event management on the other. Tracking & tracing systems only have the functions of monitoring and reporting deviations, whereas supply chain event management systems also function as simulation, control, and measurement. The central element connecting these systems is the event. It forms the information basis for mapping and matching the process sequences in the event-based systems. The events received from the supply chain partner form the basis for all downstream steps and must, therefore, contain the correct data. Since the data quality is insufficient in numerous use cases and incorrect data in supply chain event management is not considered in the literature, this paper deals with the description and typification of incorrect event data. Based on a systematic literature review, typical sources of errors in the acquisition and transmission of event data are discussed. The results are then applied to event data so that a typification of incorrect event types is possible. The results help to significantly improve event-based systems for use in practice by preventing incorrect reactions through the detection of incorrect event data

Error detection for data communication systems

A description of the problems encountered in the data communications field and the various solutions can be found in a number of diverse, and often theoretical sources. My intention in writing this thesis is to bring together, in a practical and understandable manner, the theory and the application of a method of error detection used extensively in data communication systems known as the Cyclic Redundancy Check (CRC). To provide some background on the subject, a description of a data communication system is presented, and the possible sources of error are explored in some detail. Data transmission formats are described, and a comparison of various error detection schemes is presented so that the advantages of the CRC can be more readily understood. The theory behind the CRC and its physical implementation is given, along with a detailed example showing the effectiveness of the CRC for error detection. Finally, the current state-of-the-art technology available for implementing the various error detection schemes is discussed, with particular emphasis on those technologies that perform the Cyclic Redundancy Check

Atomic characterization of Si nanoclusters embedded in SiO2 by atom probe tomography

Silicon nanoclusters are of prime interest for new generation of optoelectronic and microelectronics components. Physical properties (light emission, carrier storage...) of systems using such nanoclusters are strongly dependent on nanostructural characteristics. These characteristics (size, composition, distribution, and interface nature) are until now obtained using conventional high-resolution analytic methods, such as high-resolution transmission electron microscopy, EFTEM, or EELS. In this article, a complementary technique, the atom probe tomography, was used for studying a multilayer (ML) system containing silicon clusters. Such a technique and its analysis give information on the structure at the atomic level and allow obtaining complementary information with respect to other techniques. A description of the different steps for such analysis: sample preparation, atom probe analysis, and data treatment are detailed. An atomic scale description of the Si nanoclusters/SiO2 ML will be fully described. This system is composed of 3.8-nm-thick SiO layers and 4-nm-thick SiO2 layers annealed 1 h at 900°C