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Der Embedded Wireless-Report
(2014)
RGB-D sensors such as the Microsoft Kinect or the Asus Xtion are inexpensive 3D sensors. A depth image is computed by calculating the distortion of a known infrared light (IR) pattern which is projected into the scene. While these sensors are great devices they have some limitations. The distance they can measure is limited and they suffer from reflection problems on transparent, shiny, or very matte and absorbing objects. If more than one RGB-D camera is used the IR patterns interfere with each other. This results in a massive loss of depth information. In this paper, we present a simple and powerful method to overcome these problems. We propose a stereo RGB-D camera system which uses the pros of RGB-D cameras and combine them with the pros of stereo camera systems. The idea is to utilize the IR images of each two sensors as a stereo pair to generate a depth map. The IR patterns emitted by IR projectors are exploited here to enhance the dense stereo matching even if the observed objects or surfaces are texture-less or transparent. The resulting disparity map is then fused with the depth map offered by the RGB-D sensor to fill the regions and the holes that appear because of interference, or due to transparent or reflective objects. Our results show that the density of depth information is increased especially for transparent, shiny or matte objects.
Selective Laser Melting (SLM) is one of the Additive Manufacturing (AM) technologies applicable for producing complex geometries which are typically expensive or difficult to fabricate using conventional methods. This process has been extensively investigated experimentally for various metals and the fabrication process parameters have been established for different applications; however, fabricating 3D glass objects using SLM technology has remained a challenge so far although it could have many applications. This paper presents a summery on various experimental evaluations of a material database incorporating the build parameters of glass powder using the SLM process for jewelry applications.
Generation Y
(2014)
Mehrwert
(2014)
A novel photoexcitation method for the light-addressable potentiometric sensor (LAPS) realized a higher spatial resolution of chemical imaging. In this method, a modulated light probe, which generates the alternating photocurrent signal, is surrounded by a ring of constant light, which suppresses the lateral diffusion of photocarriers by enhancing recombination. A device simulation verified that a higher spatial resolution could be obtained by adjusting the gap between the modulated and constant light. It was also found that a higher intensity and a longer wavelength of constant light was more effective. However, there exists a tradeoff between the spatial resolution and the amplitude of the photocurrent, and thus, the signal-to-noise ratio. A tilted incidence of constant light was applied, which could achieve even higher resolution with a smaller loss of photocurrent.
A semiconductor field-effect device has been used for an enzymatically catalyzed degradation of biopolymers for the first time. This novel technique is capable to monitor the degradation process of multiple samples in situ and in real-time. As model system, the degradation of the biopolymer poly(D, L-lactic acid) has been monitored in the degradation medium containing the enzyme lipase from Rhizomucor miehei. The obtained results demonstrate the potential of capacitive field-effect sensors for degradation studies of biodegradable polymers.
High-k perovskite oxide of barium strontium titanate (BST) represents a very attractive multi-functional transducer material for the development of (bio-)chemical sensors for liquids. In this work, BST films have been applied as a sensitive transducer material for a label-free detection of adsorbed charged macromolecules (positively charged polyelectrolytes) and concentration of hydrogen peroxide vapor as well as protection insulator layer for a contactless electrolyte-conductivity sensor. The experimental results of characterization of individual sensors are presented. Special emphasis is devoted towards the development of a capacitively-coupled contactless electrolyte-conductivity sensor.
Light-addressable potentiometric sensors (LAPS) consisting of a p-Si-SiO2 and p-Si-SiO2-Au structure, respectively, have been tested for a label-free electrical detection of DNA (deoxyribonucleic acid) hybridization. Three different strategies for immobilizing single-stranded probe DNA (ssDNA) molecules on a LAPS surface have been studied and compared: (a) immobilization of thiol-modified ssDNA on the patterned Au surface via gold-thiol bond, (b) covalent immobilization of amino-modified ssDNA onto the SiO2 surface functionalized with 3-aminopropyltriethoxysilane and (c) layer-by-layer adsorption of negatively charged ssDNA on a positively charged weak polyelectrolyte layer of poly(allylamine hydrochloride).
The chemical imaging sensor, which is based on the principle of the light-addressable potentiometric sensor (LAPS), is a powerful tool to visualize the spatial distribution of chemical species on the sensor surface. The spatial resolution of this sensor depends on the diffusion of photocarriers excited by a modulated light. In this study, a novel hybrid fiber-optic illumination was developed to enhance the spatial resolution. It consists of a modulated light probe to generate a photocurrent signal and a ring of constant light, which suppresses the lateral diffusion of minority carriers excited by the modulated light. It is demonstrated that the spatial resolution was improved from 92 μm to 68 μm.
Risk management for structures with a risk of explosion should be considered very carefully when performing a risk analysis according to IEC 62305-2. In contrast to the 2006 edition of the standard, the 2010 edition describes the topic “Structures with a risk of explosion” in more detail. Moreover, in Germany separate procedures and parameters are defined for the risk analysis of structures with a risk of explosion (Supplement 3 of the German DIN EN 62305-2 standard). This paper describes the contents and the relevant calculations of this Supplement 3, together with a numerical example.
The 2nd edition of the lightning risk management
standard (IEC 62305-2) considers structures, which may
endanger environment. In these cases, the loss is not limited to
the structure itself, which is valid for usual structures. In the past
(Edition 1) this danger was simply taken into account by a special
hazard factor, multiplying the existing risk for the structure with
a number. Now, in the edition 2, we add to the risk for the
structure itself a “second risk” due to the losses outside the
structure. The losses outside can be treated independently from
what occurs inside. This is a major advantage to analyze the risk
for sensitive structures, like chemical plants, nuclear plants, or
structures containing explosives, etc. In this paper, the existing
procedure given by the European version EN 62305-2 Ed.2 is
further developed and applied to a few structures.
There is significant interest in sampling subglacial environments for geobiological studies, but they are difficult to access. Existing ice-drilling technologies make it cumbersome to maintain microbiologically clean access for sample acquisition and environmental stewardship of potentially fragile subglacial aquatic ecosystems. The IceMole is a maneuverable subsurface ice probe for clean in situ analysis and sampling of glacial ice and subglacial materials. The design is based on the novel concept of combining melting and mechanical propulsion. It can change melting direction by differential heating of the melting head and optional side-wall heaters. The first two prototypes were successfully tested between 2010 and 2012 on glaciers in Switzerland and Iceland. They demonstrated downward, horizontal and upward melting, as well as curve driving and dirt layer penetration. A more advanced probe is currently under development as part of the Enceladus Explorer (EnEx) project. It offers systems for obstacle avoidance, target detection, and navigation in ice. For the EnEx-IceMole, we will pay particular attention to clean protocols for the sampling of subglacial materials for biogeochemical analysis. We plan to use this probe for clean access into a unique subglacial aquatic environment at Blood Falls, Antarctica, with return of a subglacial brine sample.
The concept of an injective affine embedding of the quantum states into a set of classical states, i.e., into the set of the probability measures on some measurable space, as well as its relation to statistically complete observables is revisited, and its limitation in view of a classical reformulation of the statistical scheme of quantum mechanics is discussed. In particular, on the basis of a theorem concerning a non-denseness property of a set of coexistent effects, it is shown that an injective classical embedding of the quantum states cannot be supplemented by an at least approximate classical description of the quantum mechanical effects. As an alternative approach, the concept of quasi-probability representations of quantum mechanics is considered.
Our knowledge on tree responses to drought is mainly based on short-term manipulation experiments which do not capture any possible long-term adjustments in this response. Therefore, historical water channels in inner-Alpine dry valleys were used as century-long irrigation experiments to investigate adjustments in tree growth to contrasting water supply. This involved quantifying the tree-ring growth of irrigated and non-irrigated (control) Scots pine (Pinus sylvestris L.) in Valais (Switzerland), as well as European larch (Larix decidua Mill.) and black pine (Pinus nigra Arnold) in Vinschgau (Italy). Furthermore, the adjustments in radial growth of Scots pine and European larch to an abrupt stop in irrigation were analyzed.
Irrigation promoted the radial growth of all tree species investigated compared to the control: (1) directly through increased soil water availability, and (2) indirectly through increased soil nutrients and humus contents in the irrigated plots. Irrigation led to a full elimination of growth responses to climate for European larch and black pine, but not for Scots pine, which might become more sensitive to drought with increasing tree size in Valais. For the control trees, the response of the latewood increment to water availability in July/August has decreased in recent decades for all species, but increased in May for Scots pine only. The sudden irrigation stop caused a drop in radial growth to a lower level for Scots pine or similar level for larch compared to the control for up to ten years. However, both tree species were then able to adjust to the new conditions and subsequently grew with similar (Scots pine) or even higher growth rates (larch) than the control.
To estimate the impact of climate change on future forest development, the duration of manipulation experiments should be on longer time scales in order to capture adjustment processes and feedback mechanisms of forest ecosystems.
Nah- versus Nachtoderfahrungen
Nahtoderfahrungen (NTE) sind ein Phänomen aus der Kategorie „außergewöhnliche Bewusstseinserfahrungen“. Sie treten in unmittelbarer Nähe des eigenen Todes auf. Oft, aber nicht immer, handelt es sich dabei um Erfahrungen von Personen, die durch ärztliche Maßnahmen wiederbelebt wurden und später davon berichten (NTE-ler). Jedoch kommen solche Phänomene auch bei Menschen vor, die während einer schweren Erkrankung eine lebensbedrohliche Krise haben, hiervon aber spontan genesen.
Den NTE ähnlich sind auch sogenannte Nachtod-erfahrungen sowie spontane Erlebnisse, die im Rahmen anderer außergewöhnlicher Stresssituationen auftreten. Von Nachtoderfahrungen spricht man, wenn die Betroffenen anlässlich des Todes von geliebten Angehörigen oder Freunden Erlebnisse haben, die inhaltlich ebenfalls, zumindest aber teilweise, denen von NTE entsprechen.
Nachtoderfahrungen sowie spontane NTE-ähnliche Erlebnisse unterscheiden sich jedoch von den echten NTE zumeist sowohl quantitativ als auch qualitativ. Unter einem quantitativen Unterschied versteht man in diesem Zusammenhang eine in der Regel geringer ausgeprägte Komplexität, als sie sehr vielen NTE zu eigen ist. Da sich aber auch viele NTE selbst bezüglich ihrer Komplexität unterscheiden, ist der Hauptunterschied qualitativer Natur: Echte NTE besitzen gegenüber den anderen hier erwähnten Phänomenen eine größere inhaltliche und emotionale Tiefe. Sie begleiten die Betroffenen anschließend ein Leben lang – zumeist mit positiven, in Einzelfällen aber auch mit negativen Folgen, die bis zu einem späteren Suizid reichen können.
Die genannten außergewöhnlichen Bewusstseinsphänomene lassen sich in ihrer Gesamtheit bei rund 5 % der Bevölkerung finden. NTE im Speziellen haben hiervon einen durchaus bedeutenden Anteil. Je nach Studie geben zwischen 18 % und 40 % aller Personen, die reanimiert wurden, an, währenddessen eine NTE erlebt zu haben. Dass nicht alle eine solche Erfahrung machen, wird von Kritikern gern dahingehend interpretiert, NTE seien rein physiologischer und keineswegs spiritueller Natur. Jedoch sollte man bedenken, dass im Fall einer rein neurophysiologischen Grundlage von NTE dann bei jedem ein solches Phänomen zu erwarten wäre, so wie beispielsweise auch die Symptome einer Hypoglykämie im Wesentlichen immer dieselben sind.
Persistent infection with the high-risk Human Papillomavirus type 16 (HPV 16) is the causative event for the development of cervical cancer and other malignant tumors of the anogenital tract and of the head and neck. Despite many attempts to develop therapeutic vaccines no candidate has entered late clinical trials. An interesting approach is a DNA based vaccine encompassing the nucleotide sequence of the E6 and E7 viral oncoproteins. Because both proteins are consistently expressed in HPV infected cells they represent excellent targets for immune therapy. Here we report the development of 8 DNA vaccine candidates consisting of differently rearranged HPV-16 E6 and E7 sequences within one molecule providing all naturally occurring epitopes but supposedly lacking transforming activity. The HPV sequences were fused to the J-domain and the SV40 enhancer in order to increase immune responses. We demonstrate that one out of the 8 vaccine candidates induces very strong cellular E6- and E7- specific cellular immune responses in mice and, as shown in regression experiments, efficiently controls growth of HPV 16 positive syngeneic tumors. This data demonstrates the potential of this vaccine candidate to control persistent HPV 16 infection that may lead to malignant disease. It also suggests that different sequence rearrangements influence the immunogenecity by an as yet unknown mechanism.
DNA-hybridization detection using light-addressable potentiometric sensor modified with gold layer
(2014)
Multi-parameter detection for supporting monitoring and control of biogas processes in agriculture
(2014)
For the sterilisation of aseptic food packages it is taken advantage of the microbicidal properties of hydrogen peroxide (H2O2). Especially, when applied in vapour phase, it has shown high potential of microbial inactivation. In addition, it offers a high environmental compatibility compared to other chemical sterilisation agents, as it decomposes into oxygen and water, respectively. Due to a lack in sensory detection possibilities, a continuous monitoring of the H2O2 concentration was recently not available. Instead, the sterilisation efficacy is validated using microbiological tests. However, progresses in the development of calorimetric gas sensors during the last 7 years have made it possible to monitor the H2O2 concentration during operation. This chapter deals with the fundamentals of calorimetric gas sensing with special focus on the detection of gaseous hydrogen peroxide. A sensor principle based on a calorimetric differential set-up is described. Special emphasis is given to the sensor design with respect to the operational requirements under field conditions. The state-of-the-art regarding a sensor set-up for the on-line monitoring and secondly, a miniaturised sensor for in-line monitoring are summarised. Furthermore, alternative detection methods and a novel multi-sensor system for the characterisation of aseptic sterilisation processes are described.
In Folge mehrjähriger statistischer Untersuchungen an der FH Aachen ist unter anderem ein Eingangstest entstanden, der als Diagnosetool für einen erfolgreichen Studieneinstieg verwendet wird. Es hat sich herausgestellt, dass ein Testergebnis von weniger als 25 (von maximal 56 erreichbaren) Punkten die Chance auf einen erfolgreichen Studieneinstieg deutlich verringert. Ungefähr die Hälfte aller Erstsemester hat weniger als 25 Punkte im Eingangstest. Weniger als 20 % dieser Gruppe bestehen innerhalb eines Jahres die Klausur Mathematik 1. Die investierte Zeit von zwei Semestern ist mit Blick auf den Wissenszuwachs und damit letztendlich den Studienerfolg nicht effizient genutzt. Deshalb haben wir im WS 2013/14 einen semesterbegleitenden Anpassungskurs für diese Gruppe installiert. Ziel eines solchen Kurses ist es, die Student/innen innerhalb eines Jahres in die Lage zu versetzen, nach zwei Semestern problemlos den Vorlesungen in Mathematik zu folgen. Dieser Artikel beschreibt das Konzept dieses Anpassungskurses und zeigt erste Ergebnisse und Probleme des Pilotdurchgangs auf.
Begriffsbestimmungen
(2014)