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Integration of BACNET OPC UA-Devices Using a JAVA OPC UA SDK Server with BACNET Open Source Library
(2014)
Energy management in distribution grids is one of the key challenges that needs to be overcome to increase the share of fluctuating renewable energies. Current control systems for energy management mainly demonstrate centralized- or decentralized-hierarchical control structures. Very few systems manifest a fully decentralized multiagent-based control structure. Multiagent-based control systems promise to be an advantageous approach for the future distributed energy supply system because no central control entity is necessary, which eases parameterization in case of grid topology changes, and the agents are more stable against failures and changes of control topologies. Research is necessary to prove these benefits. In this study, we introduce a design of a multiagent-based voltage control system for low-voltage grids. In detail we introduce cooperative decision-making processes and software solutions that allow the agents to perceive and control their environment, the agent-discovery and localization in different types of communication networks, agent-to-agent communication, and the integration of the multiagent system in existing grid-control infrastructures. Furthermore, the study proposes how different existing technologies can be combined into an applicable multiagent-based voltage control system: the Java/OSGi-based OpenMUC framework allows a generic field–device interaction; peer-to-peer discovery and session establishment functionalities are combined with the agent communication defined by the Foundation for Intelligent Physical Agents (FIPA). The ripple control-signal technology is applied as a fallback communication between the agent and a central grid-control center.
Private households constitute a considerable share of Europe's electricity consumption. The current electricity distribution system treats them as effectively passive individual units. In the future, however, users of the electricity grid will be involved more actively in the grid operation and can become part of intelligent networked collaborations. They can then contribute the demand and supply flexibility that they dispose of and, as a result, help to better integrate renewable energy in-feed into the distribution grids.
A wide range catalyst screening with noble metal and oxide catalysts for a metal–air battery with an aqueous alkaline electrolyte was carried out. Suitable catalysts reduce overpotentials during the charge and discharge process, and therefore improve the round-trip efficiency of the battery. In this case, the electrodes will be used as optimized cathodes for a future lithium–air battery with an aqueous alkaline electrolyte. Oxide catalysts were synthesized via atmospheric plasma spraying. The screening showed that IrO2, RuO2, La0.6Ca0.4Co3, Mn3O4, and Co3O4 are promising bi-functional catalysts. Considering the high price for the noble metal catalysts further investigations of the oxide catalysts were carried out to analyze their electrochemical behavior at varied temperatures, molarities, and in case of La1−x Ca x CoO3 a varying calcium content. Additionally all catalysts were tested in a longterm test to proof cyclability at varied molarities. Further investigations showed that Co3O4 seems to be the most promising bi-functional catalyst of the tested oxide catalysts. Furthermore, it was shown that a calcium content of x = 0.4 in LCCO has the best performance.
Lithium-oxygen cells with organic electrolyte suffer high overpotentials during charge, indicating asymmetric charge/discharge reaction mechanisms. We present a multi-physics dynamic modeling and simulation study of the Li/O2 cell cycling behavior. We present three different multi-step mechanisms of the 2 Li + O2 ⇄ Li2O2 cell reaction, (A) a reversible 5-step mechanism, (B) a partially irreversible 6-step mechanism, and (C) a partially irreversible 8-step mechanism that includes reactions of a redox mediator. Model predictions are compared to experimental galvanostatic cycling data of Swagelok cells without and with 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) as redox mediator. All mechanisms are able to predict the discharge behavior in good agreement to the experimental results. The experimentally observed high charge overpotentials as well as their reduction by using a redox mediator can be qualitatively reproduced with the irreversible reaction mechanisms. However, the particular shape of the experimental charge curve with continuously increasing charge overpotential cannot be reproduced with the present mechanisms.
Chronic insomnia is defined by difficulties in falling asleep, maintaining sleep, and early morning awakening, and is coupled with daytime consequences such as fatigue, attention deficits, and mood instability. These symptoms persist over a period of at least 3 months (Diagnostic and Statistical Manual 5 criteria). Chronic insomnia can be a symptom of many medical, neurological, and mental disorders. As a disorder, it incurs substantial health-care and occupational costs, and poses substantial risks for the development of cardiovascular and mental disorders, including cognitive deficits. Family and twin studies confirm that chronic insomnia can have a genetic component (heritability coefficients between 42% and 57%), whereas the investigation of autonomous and central nervous system parameters has identified hyperarousal as a final common pathway of the pathophysiology, implicating an imbalance of sleep–wake regulation consisting of either overactivity of the arousal systems, hypoactivity of the sleep-inducing systems, or both. Insomnia treatments include benzodiazepines, benzodiazepine-receptor agonists, and cognitive behavioural therapy. Treatments currently under investigation include transcranial magnetic or electrical brain stimulation, and novel methods to deliver psychological interventions.
Digital networked communications are the key to all Internet-of-Things applications, especially to smart metering systems and the smart grid. In order to ensure a safe operation of systems and the privacy of users, the transport layer security (TLS) protocol, a mature and well standardized solution for secure communications, may be used. We implemented the TLS protocol in its latest version in a way suitable for embedded and resource-constrained systems. This paper outlines the challenges and opportunities of deploying TLS in smart metering and smart grid applications and presents performance results of our TLS implementation. Our analysis shows that given an appropriate implementation and configuration, deploying TLS in constrained smart metering systems is possible with acceptable overhead.
The increasing number of transistors being clocked at high frequencies of modern microprocessors lead to an increasing power consumption, which calls for an active dynamic thermal management. In a research project a system environment has been developed, which includes thermal modeling of the microprocessor in the board system, a software environment to control the characteristics of the system’s timing behavior, and a modified Linux scheduler, which is enhanced with a prediction controller. Measurement results are shown for this development for a Freescale i.MX6Q quad-core microprocessor.
Cardiac resynchronization therapy with atrioventricular and interventricular delay optimized biventricular pacing is an established therapy for symptomatic heart failure patients with prolongation of QRS duration, left bundle branch block and reduced left ventricular ejection fraction. The aim of the investigation was to evaluate right atrial, right ventricular and left ventricular electrical signals of implantable electronic cardiac devices with and without signal averaging technique with novel LabVIEW software. Electrical interatrial conduction delay and inter-ventricular conduction delay may be useful parameters to evaluate electrical atrial and ventricular desynchronization in heart failure patients.
Cardiac resynchronization therapy (CRT) is an established therapy for heart failure patients and improves quality of life in patients with sinus rhythm, reduced left ventricular ejection fraction (LVEF), left bundle branch block and wide QRS duration. Since approximately sixty percent of heart failure patients have a normal QRS duration they do not benefit or respond to the CRT. Cardiac contractility modulation (CCM) releases nonexcitatoy impulses during the absolute refractory period in order to enhance the strength of the left ventricular contraction. The aim of the investigation was to evaluate differences in cardiac index between optimized and nonoptimized CRT and CCM devices versus standard values. Impedance cardiography, a noninvasive method was used to measure cardiac index (CI), a useful parameter which describes the blood volume during one minutes heart pumps related to the body surface. CRT patients indicate an increase of 39.74 percent and CCM patients an improvement of 21.89 percent more cardiac index with an optimized device.
Transcatheter aortic valve implantation is a therapy for patients with reduced left ventricular ejection fraction and symptomatic aortic stenosis. The aim of the study was to compare the pre-and post- transcatheter aortic valve implantation procedures to determine the QRS and QT ventricular conduction times as a potential predictor of permanent pacemaker therapy requirement after transcatheter aortic valve implantation. QRS and QT ventricular conduction times were prolonged after transcatheter aortic valve implantation in heart failure patients with permanent dual chamber pacemaker therapy after transcatheter aortic valve implantation. QRS and QT ventricular conduction times may be useful parameters to evaluate the risk of post-procedural ventricular conduction block and permanent pacemaker therapy in transcatheter aortic valve implantation.
The instability of ultra-thin films of an electrolyte bordering a dielectric gas in an external tangential electric field is scrutinized. The solid wall is assumed to be either a conducting or charged dielectric surface. The problem has a steady one-dimensional solution. The theoretical results for a plug-like velocity profile are successfully compared with available experimental data. The linear stability of the steady-state flow is investigated analytically and numerically. Asymptotic long-wave expansion has a triple-zero singularity for a dielectric wall and a quadruple-zero singularity for a conducting wall, and four (for a conducting wall) or three (for a charged dielectric wall) different eigenfunctions. For infinitely small wave numbers, these eigenfunctions have a clear physical meaning: perturbations of the film thickness, of the surface charge, of the bulk conductivity, and of the bulk charge. The numerical analysis provides an important result: the appearance of a strong short-wave instability. At increasing Debye numbers, the short-wave instability region becomes isolated and eventually disappears. For infinitely large Weber numbers, the long-wave instability disappears, while the short-wave instability persists. The linear stability analysis is complemented by a nonlinear direct numerical simulation. The perturbations evolve into coherent structures; for a relatively small external electric field, these are large-amplitude surface solitary pulses, while for a sufficiently strong electric field, these are short-wave inner coherent structures, which do not disturb the surface.
The automatic classification of the modulation format of a detected signal is the intermediate step between signal detection and demodulation. If neither the transmitted data nor other signal parameters such as the frequency offset, phase offset and timing information are known, then automatic modulation classification (AMC) is a challenging task in radio monitoring systems. The approach of clustering algorithms is a new trend in AMC for digital modulations. A novel algorithm called `highest constellation pattern matching' is introduced to identify quadrature amplitude modulation and phase shift keying signals. The obtained simulation and measurement results outperform the existing algorithms for AMC based on clustering. Finally, it is shown that the proposed algorithm works in a real monitoring environment.
A new yield function for lamellar gray cast iron materials is proposed. The new model is able to describe the results of recently performed microstructure-based finite-element computations that resolve the three dimensional yield surface of three different gray cast irons. The yield function requires only the yield stress in tension and compression of the respective material as model parameters. Furthermore, the algorithmic formulation of the new model is assessed for numerical robustness and efficiency.
BACKGROUND:
While hearing aids for a contralateral routing of signals (CROS-HA) and bone conduction devices have been the traditional treatment for single-sided deafness (SSD) and asymmetric hearing loss (AHL), in recent years, cochlear implants (CIs) have increasingly become a viable treatment choice, particularly in countries where regulatory approval and reimbursement schemes are in place. Part of the reason for this shift is that the CI is the only device capable of restoring bilateral input to the auditory system and hence of possibly reinstating binaural hearing. Although several studies have independently shown that the CI is a safe and effective treatment for SSD and AHL, clinical outcome measures in those studies and across CI centers vary greatly. Only with a consistent use of defined and agreed-upon outcome measures across centers can high-level evidence be generated to assess the safety and efficacy of CIs and alternative treatments in recipients with SSD and AHL.
METHODS:
This paper presents a comparative study design and minimum outcome measures for the assessment of current treatment options in patients with SSD/AHL. The protocol was developed, discussed, and eventually agreed upon by expert panels that convened at the 2015 APSCI conference in Beijing, China, and at the CI 2016 conference in Toronto, Canada.
RESULTS:
A longitudinal study design comparing CROS-HA, BCD, and CI treatments is proposed. The recommended outcome measures include (1) speech in noise testing, using the same set of 3 spatial configurations to compare binaural benefits such as summation, squelch, and head shadow across devices; (2) localization testing, using stimuli that rove in both level and spectral content; (3) questionnaires to collect quality of life measures and the frequency of device use; and (4) questionnaires for assessing the impact of tinnitus before and after treatment, if applicable.
CONCLUSION:
A protocol for the assessment of treatment options and outcomes in recipients with SSD and AHL is presented. The proposed set of minimum outcome measures aims at harmonizing assessment methods across centers and thus at generating a growing body of high-level evidence for those treatment options.
n this work a mathematical model for describing the performance of lithium-ion battery electrodes consisting of porous active material particles is presented. The model represents an extension of the Newman-type model, accounting for the agglomerate structure of the active material particles, here Li(Ni1/3Co1/3Mn1/3)O2 (NCM) and Li(Ni1/3Co1/3Al1/3)O2 (NCA). To this goal, an additional pore space is introduced on the active material level. The space is filled with electrolyte and a charge-transfer reaction takes place at the liquid-solid interface within the porous active material particles. Volume-averaging techniques are used to derive the model equations. A local Thiele modulus is defined and provides an insight into the potentially limiting factors on the active material level. The introduction of a liquid-phase ion transport within the active material reduces the overall transport losses, while the additional active surface area within the agglomerate lowers the charge-transfer resistance. As a consequence, calculated discharge capacities are higher for particles modeled as agglomerates. This finding is more pronounced in the case of high C-rates
MITK-OpenIGTLink for combining open-source toolkits in real-time computer-assisted interventions
(2016)
PURPOSE:
Due to rapid developments in the research areas of medical imaging, medical image processing and robotics, computer-assisted interventions (CAI) are becoming an integral part of modern patient care. From a software engineering point of view, these systems are highly complex and research can benefit greatly from reusing software components. This is supported by a number of open-source toolkits for medical imaging and CAI such as the medical imaging interaction toolkit (MITK), the public software library for ultrasound imaging research (PLUS) and 3D Slicer. An independent inter-toolkit communication such as the open image-guided therapy link (OpenIGTLink) can be used to combine the advantages of these toolkits and enable an easier realization of a clinical CAI workflow.
METHODS:
MITK-OpenIGTLink is presented as a network interface within MITK that allows easy to use, asynchronous two-way messaging between MITK and clinical devices or other toolkits. Performance and interoperability tests with MITK-OpenIGTLink were carried out considering the whole CAI workflow from data acquisition over processing to visualization.
RESULTS:
We present how MITK-OpenIGTLink can be applied in different usage scenarios. In performance tests, tracking data were transmitted with a frame rate of up to 1000 Hz and a latency of 2.81 ms. Transmission of images with typical ultrasound (US) and greyscale high-definition (HD) resolutions of [Formula: see text] and [Formula: see text] is possible at up to 512 and 128 Hz, respectively.
CONCLUSION:
With the integration of OpenIGTLink into MITK, this protocol is now supported by all established open-source toolkits in the field. This eases interoperability between MITK and toolkits such as PLUS or 3D Slicer and facilitates cross-toolkit research collaborations. MITK and its submodule MITK-OpenIGTLink are provided open source under a BSD-style licence ( http://mitk.org )
Cardiac resynchronization therapy is an established therapy for heart failure patients. The aim of the study was to evaluate electrical left cardiac atrioventricular delay and interventricular desynchronization in sinus rhythm cardiac resynchronization therapy responder and non-responder. Cardiac electrical desynchronization were measured by surface ECG and focused transesophageal bipolar left atrial and left ventricular ECG before implantation of cardiac resynchronization therapy defibrillators. Preoperative electrical cardiac desynchronization was 195.7 ± 46.7 ms left cardiac atrioventricular delay and 74.8 ± 24.5 ms interventricular delay in cardiac resynchronization therapy responder. Cardiac resynchronization therapy responder New York Heart Association class improved during long term biventricular pacing. Transesophageal left cardiac atrioventricular delay and interventricular delay may be additional useful parameters to improve patient selection for cardiac resynchronization therapy.
Electrochemical impedance spectroscopy (EIS) is a widely-used diagnostic technique to characterize electrochemical processes. It is based on the dynamic analysis of two electrical observables, that is, current and voltage. Electrochemical cells with gaseous reactants or products (e.g., fuel cells, metal/air cells, electrolyzers) offer an additional observable, that is, the gas pressure. The dynamic coupling of current and/or voltage with gas pressure gives rise to a number of additional impedance definitions, for which we use the term electrochemical pressure impedance. It also gives rise to different experimental probing approaches. In this article we present a model-based study of electrochemical pressure impedance spectroscopy (EPIS). Possible quantifications and realizations of EPIS are discussed. The study of generic cell geometries consisting of gas reservoir, diffusion layer(s) and electrochemically active layer(s) reveals distinct spiral-shaped features in the Nyquist plot. Using the example of a sodium/oxygen (Na/O2) cell, the dynamic spatiotemporal behavior of the state variables is quantified and interpreted. Results are compared to first experimental EPIS measurements by Hartmann et al. [J. Phys. Chem. C118, 1461, 2014]. A sensitivity analysis highlights the properties of EPIS with respect to geometric, transport, and kinetic parameters. We demonstrate that EPIS is sensitive to transport parameters that are not well-accessible with standard EIS.
Im vorliegenden Beitrag wird beschrieben, wie bereits entworfene Zustandsregler für proportional geregelte Systeme ohne Rechentotzeit auf einfache Art und Weise für Systeme mit Reglerintegratoren bzw. mit Rechentotzeit erweitert werden können. Das Ziel ist hierbei, den Aufwand zur Ermittlung der Reglermatrix zu reduzieren. Hierbei soll die bereits vorhandene, optimierte Regelkreisdynamik so wenig wie möglich verändert werden, wodurch bei Mehrgrößensystemen hinzukommende Freiheitsgrade sinnvoll festgelegt werden. Die Betrachtungen erfolgen für lineare zeitdiskrete Systeme und werden anhand eines Beispiels aus der elektrischen Antriebstechnik veranschaulicht.
Im Rahmen der Cochleaimplantat (CI)-Versorgung werden sowohl intraoperativ als auch postoperativ verschiedene elektrische und elektrophysiologische Diagnostikverfahren eingesetzt, bei denen elektrische Messgrößen vom CI erfasst und elektrophysiologische Messungen bei CI-Patienten durchgeführt werden. Zu den elektrophysiologischen Diagnostikverfahren zählen die Messung der elektrisch evozierten Summenaktionspotenziale des Hörnervs, die Registrierung der elektrisch evozierten auditorischen Hirnstammpotenziale und die Erfassung der elektrisch evozierten auditorischen kortikalen Potenziale. Diese Potenziale widerspiegeln die Erregung des Hörnervs und die Reizverarbeitung in verschiedenen Stationen der aufsteigenden Hörbahn bei intracochleärer elektrischer Stimulation mittels eines CI. Bei den aktuellen CI sind die Beurteilung der Elektrodenlage sowie die Prüfung der Ankopplung des Implantats an den Hörnerv wichtige Anwendungsgebiete der elektrophysiologischen Diagnostikverfahren. Ein weiteres bedeutendes Einsatzfeld stellt die Prüfung der Reizverarbeitung in der Hörbahn dar. Das Hauptanwendungsgebiet dieser Verfahren bildet jedoch die Unterstützung der Anpassung der CI-Sprachprozessoren bei Säuglingen und Kleinkindern auf der Basis elektrophysiologischer Schwellen.
Structured Innovation with TRIZ in Science and Industry - Creating Value for Customers and Society
(2016)
Lithium–oxygen cells with nonaqueous electrolyte show high overpotentials during charge, indicating asymmetric charge/discharge reaction mechanisms. We present a kinetic modeling and simulation study of the lithium–oxygen cell cycling behavior. The model includes a multistep reaction mechanism of the cell reaction (2Li + O2 ⇄ Li2O2) forming lithium peroxide by precipitation, coupled to a 1D porous-electrode transport model. We apply the model to study the asymmetric discharge/charge characteristics and analyze the influence of a redox mediator dissolved homogeneously in the liquid electrolyte. Model predictions are compared to experimental galvanostatic cycling data of cells without and with 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) as redox mediator. The predicted discharge behavior shows good agreement with the experimental results. A spatiotemporal analysis of species concentrations reveals inhomogeneous distributions of dissolved oxygen and reaction products within the cathode during discharge. The experimentally observed charge overpotentials as well as their reduction by using a redox mediator can be qualitatively reproduced with a partially irreversible reaction mechanism. However, the proposed models fail to reproduce the particular shape of the experimental charge curve with continuously increasing charge overpotential, which implies that part of the reaction mechanism is still open for investigation in future work.
Serendipities in der Medizin
(2016)
Zufälle begleiten unser Leben. Auch bei wichtigen Entdeckungen und Entwicklungen in der Medizin spielt der „Zufall“ (engl. „serendipity“) eine Rolle. Hierzu gehören u. a. die Mendelschen Gesetze, die Ermittlung der menschlichen Chromosomenzahl, die Entdeckung der DNS durch Watson und Crick, der PAP-Test oder die Entdeckung der Röntgenstrahlung und der Radioaktivität. Aber auch und gerade in der Pharmakologie gibt es viele Beispiele für Serendipitäten. Einige gehen eng mit Zufällen bei der Entdeckung der Bakteriologie einher.
The interaural time difference (ITD) is an important cue for the localization of sounds. ITD changes as little as 10 μs can be detected by the human auditory system. By provision of one ear with a cochlear implant (CI) ITD are altered due to the partial replacement of the peripheral auditory system. A hearing aid (HA), in contrast, does not replace but adds a processing delay component to the peripheral auditory system extending ITD. The aim of the present study was to quantify interaural stimulation timing between these different modalities to estimate the need for central auditory temporal compensation in single sided deaf CI users or bimodal CI/HA users. For this purpose, wave V latencies of auditory brainstem responses evoked either acoustically (ABR) or electrically via the CI (EABR) have been measured. The sum of delays consisting of CI signal processing measured in the MED-EL OPUS2 audio processor and EABR wave V latencies evoked on different intracochlear sites allowed an estimation of the entire CI channel-specific delay for MED-EL MAESTRO CI systems. We compared these values with ABR wave V latencies measured in the contralateral normal hearing or HA provided ear in different frequency bands. The results showed that EABR wave V latencies were consistently shorter than those evoked acoustically in the unaided normal hearing ear. Thus, artificial delays within the audio processor can be implemented to adjust interaural stimulation timing. The currently implemented group delays in the MED-EL CI system turned out to be reasonably similar to those of the unaided ear. For adjustment of CI and contralateral HA, in contrast, an adjustable additional across-frequency delay in the range of 1–11 ms implemented in the CI would be required. Especially for bimodal CI/HA users the adjustment of interaural stimulation timing may induce improved binaural hearing, reduced need for central auditory temporal compensation and increased acceptance of the CI/HA provision.
This paper presents an overview of the coding aspects of a GNSS receiver. Coding allows detection and correction of channel-induced errors at the receiver, here the focus is on the mitigation of threats from malicious interferences. Although the effects of interference at different stages of GNSS baseband processing has been deeply analyzed in the literature, little attention was devoted to its impact on the navigation message decoding stage. Theis paper provides an introduction to the various coding schemes employed by current GNSS signals, discussing their performance in the presence of noise in terms of block-error rate. Additionally, the benefits of soft-decoding schemes for navigation message decoding are highlighted when jamming interferences are present. The proposed scheme requires estimating the noise plus interference power, yielding to enhanced decoding performances under severe jamming conditions. Finally, cryptographic schemes as a means of providing anti-spoofing for geosecurity location-based services, and their potential vulnerability are discussed, with particular emphasis on the dependence on the dependence of the scheme on successful navigation message decoding
The ability to detect a target signal masked by noise is improved in normal-hearing listeners when interaural phase differences (IPDs) between the ear signals exist either in the masker or in the signal. To improve binaural hearing in bilaterally implanted cochlear implant (BiCI) users, a coding strategy providing the best possible access to IPD is highly desirable. In this study, we compared two coding strategies in BiCI users provided with CI systems from MED-EL (Innsbruck, Austria). The CI systems were bilaterally programmed either with the fine structure processing strategy FS4 or with the constant rate strategy high definition continuous interleaved sampling (HDCIS). Familiarization periods between 6 and 12 weeks were considered. The effect of IPD was measured in two types of experiments: (a) IPD detection thresholds with tonal signals addressing mainly one apical interaural electrode pair and (b) with speech in noise in terms of binaural speech intelligibility level differences (BILD) addressing multiple electrodes bilaterally. The results in (a) showed improved IPD detection thresholds with FS4 compared with HDCIS in four out of the seven BiCI users. In contrast, 12 BiCI users in (b) showed similar BILD with FS4 (0.6 ± 1.9 dB) and HDCIS (0.5 ± 2.0 dB). However, no correlation between results in (a) and (b) both obtained with FS4 was found. In conclusion, the degree of IPD sensitivity determined on an apical interaural electrode pair was not an indicator for BILD based on bilateral multielectrode stimulation.
The famous violin virtuoso Nicolò Paganini (born on 27 October 1782 in Genoa, died on 27 May 1840 in Nice) left us with many puzzles. An interesting aspect is his hair: In the 19th century, hair given away as a token of friendship or romantic love became very popular, and Paganini also seems to have made use of this fad. In 2009, a lock of hair, purportedly that of Paganini, kept in a locked presentation box together with a bilingual autograph inscription saying: "Alla Signora Chatterton avec les compliments de Nicolò Paganini" was bought at an auction. From this hair lock a sample was taken and was investigated morphologically by using digital light microscopy (digital microscope VHX-100, Keyence) in reflected and transmitted light with and without polarization at different magnifications up to 1:5,000. The sample was then compared with a hair sample from the possession of the Paganini family, which had been microscopically examined in 2012 by the co-author of this paper yielding numerous figures with measurement results that had been stored and could be retrieved for direct comparison. The hair sample consisted of ten strands of hair or hair fragments and was investigated with great effort for the following parameters: exogenous hair damage, especially feeding traces caused by parasites, modeling and angulation of hairs, hair thickness, medulla and pigmentation, curling and mercury load on the trace material. After evaluation of all findings not only a non-exclusion of identity can be determined, but due to the broad match of also rare findings there is no reasonable doubt about their identity. In addition, the findings suggest that the studied hair samples are in fact from Paganini's head. The present case of Nicolò Paganini's hair lock is also an excellent starting point for reflections on the probative value of trace hair investigations. This point is also critically discussed in the paper. Finally, this study shows that said lock of hair had probably really been dedicated and given to Eliza Davenport Latham (born on 25 November 1806, died on 9 January 1877), the future wife of the, at that time, best-known and most famous English harpist John Balsir Chatterton (born on 25 November 1804, died on 9 April 1871). Paganini must have met her on his concert tour 1831/32, where he had travelled to Paris, London, the rest of England, Scotland and Ireland.
Electric arc furnaces (EAF) are complex industrial plants whose actual behavior depends upon numerous factors. Due to its energy intensive operation, the EAF process has always been subject to optimization efforts. For these reasons, several models have been proposed in literature to analyze and predict different modes of operation. Most of these models focused on the processes inside the vessel itself. The present paper introduces a dynamic, physics-based model of a complete EAF plant which consists of the four subsystems vessel, electric system, electrode regulation, and off-gas system. Furthermore the solid phase is not treated to be homogenous but a simple spatial discretization is employed. Hence it is possible to simulate the energy input by electric arcs and fossil fuel burners depending on the state of the melting progress. The model is implemented in object-oriented, equation-based language Modelica. The simulation results are compared to literature data.
Proton Exchange Membrane Fuel Cells (PEMFC) are energy efficient and environmentally friendly alternatives to conventional energy conversion systems in many yet emerging applications. In order to enable prediction of their performance and durability, it is crucial to gain a deeper understanding of the relevant operation phenomena, e.g., electrochemistry, transport phenomena, thermodynamics as well as the mechanisms leading to the degradation of cell components. Achieving the goal of providing predictive tools to model PEMFC performance, durability and degradation is a challenging task requiring the development of detailed and realistic models reaching from the atomic/molecular scale over the meso scale of structures and materials up to components, stack and system level. In addition an appropriate way of coupling the different scales is required.
This review provides a comprehensive overview of the state of the art in modeling of PEMFC, covering all relevant scales from atomistic up to system level as well as the coupling between these scales. Furthermore, it focuses on the modeling of PEMFC degradation mechanisms and on the coupling between performance and degradation models.
The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users
(2016)
Objective: The present study evaluated whether the poorer baseline performance of cochlear implant (CI) users or the technical and/or physiological properties of CI stimulation are responsible for the absence of masking release. Design: This study measured speech reception thresholds (SRTs) in continuous and modulated noise as a function of signal to noise ratio (SNR). Study sample: A total of 24 subjects participated: 12 normal-hearing (NH) listeners and 12 subjects provided with recent MED-EL CI systems. Results: The mean SRT of CI users in continuous noise was −3.0 ± 1.5 dB SNR (mean ± SEM), while the normal-hearing group reached −5.9 ± 0.8 dB SNR. In modulated noise, the difference across groups increased considerably. For CI users, the mean SRT worsened to −1.4 ± 2.3 dB SNR, while it improved for normal-hearing listeners to −18.9 ± 3.8 dB SNR. Conclusions: The detrimental effect of fluctuating maskers on SRTs in CI users shown by prior studies was confirmed by the current study. Concluding, the absence of masking release is mainly caused by the technical and/or physiological properties of CI stimulation, not just the poorer baseline performance of many CI users compared to normal-hearing subjects. Speech understanding in modulated noise was more robust in CI users who had a relatively large electrical dynamic range.
Nickel cobalt aluminum oxide (NCA) based lithium-ion battery electrodes exhibit a distinct asymmetry in discharge/charge behavior towards high bulk stoichiometry (low state of charge). We show that basic electrochemical relationships, that is, the Nernst equation and the Butler-Volmer equation, are able to reproduce this behavior when a two-step reaction mechanism is assumed. The two-step mechanism consists of (1) lithium-ion adsorption from the electrolyte onto the active material particle surface under electron transfer, and (2) intercalation of surface-adsorbed lithium atoms into the bulk material. The asymmetry of experimental half-cell data of an NCA electrode cycled at 0.1 C-rate can be quantitatively reproduced with this simple model. The model parameters show two alternative solutions, predicting either a saturated (highly-covered) or a depleted surface for high bulk lithiation.
We present a novel scheme for Slotted ALOHA random access systems that combines physical-layer network coding (PLNC) with multiuser detection (MUD). The PLNC and MUD are applied jointly at the physical layer to be able to extract any linear combination of messages experiencing a collision within a slot. The set of combinations extracted from a whole frame is then processed by the receiver to recover the original packets. A simple precoding stage at the transmitting terminals allows the receiver to further decrease the packet loss rate. We present results for the decoding at the physical layer as well as several performance measures at frame level, namely, throughput, packet loss rate, and energy efficiency. The results we present are promising and suggest that a cross-layer approach leveraging on the joint use of PLNC and MUD can significantly improve the performance of random access systems in the presence of slow fading.
Die Namen Cormack und Hounsfield sind für den Radiologen zu einem wichtigen Synonym für die Computertomographie (CT) geworden. Der mathematische Wegbereiter für die CT, Johann Radon, kommt in der radiologischen Diskussion und den historischen Rückblicken hingegen oft zu Unrecht zu kurz. Die folgende Kurzübersicht möchte daher dem interessierten Leser die wichtigsten historischen Eckdaten zu dem in vielerlei Hinsicht bewegenden Leben und Wirken dieses großen Mathematikers näherbringen.
This is a commentary note on the situation of functional neuroimaging in psychiatry. With this we would like to encourage psychiatrists and the journal editors of psychiatric and related journals to at least rethink the role of functional neuroimaging in this discipline and use these imaging techniques in their various aspects of clinical diagnosis and therapy regimens,respectively.