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Im Jahr 1504 verlor der deutsche Ritter Gottfried („Götz“) von Berlichingen seine
rechte Hand. Schon während seiner Genesung dachte er daran, die Hand zu ersetzen,
und beauftragte bald darauf die erste Handprothese, die sogenannte „Eiserne Hand“.
Jahre später wurde die aufwändigere zweite „Eiserne Hand“ gebaut. Wir haben die erste
Prothese auf der Basis früherer Literaturdaten von
Quasigroch (1982) mit Hilfe von 3-D
Computer-Aided Design (CAD) rekonstruiert. Dazu mussten einige Abmessungen angepasst
und ein paar Annahmen für das CAD-Modell gemacht werden. Die historische passive
Prothese des Götz von Berlichingen ist für die moderne Neuroprothetik interessant, da sie
eine Alternative zu komplexen invasiven Brain-Machine-Interface-Konzepten darstellen
könnte, wo diese Konzepte nicht notwendig, möglich oder vom Patienten gewünscht sind.
In this study, we tested the function of a replica of the over 500-year-old original of the
famous Franconian Imperial Knight Götz von Berlichingen’s first “iron hand”, which we
reconstructed by computer-aided design (CAD) and recently printed using a multi-material
3D printer. In different everyday tasks, the artificial hand prosthesis proved to be remarkably
helpful. Thus, the hand could hold a wine glass, some grapes, or a smartphone. With a
suitable pencil, even writing was possible without any problem. Although for all these
functions the healthy other hand was necessary to assist at the beginning, the artificial hand
is an astonishing mechanical aid with many possibilities. Therefore, in certain cases, the
non-invasive approach of a passive mechanical hand replacement, which is an individual,
quick and cheap solution due to modern 3D printing, may always be worth considering
also for today’s requirements.
Auf Grundlage der Computer-Aided-Design (CAD)-rekonstruierten ersten „Eisernen Hand“ des Götz von Berlichingen wird ein umgebautes, controllergesteuertes sensomotorisches Fingersystem auf seine Funktionalität beim Greifen von unterschiedlichen Gegenständen beschrieben und geprüft. Die elektronischen Finger, die den „Pinzettengriff“ nachahmen und automatisch bei dem zuvor eingestellten Anpressdruck abschalten, bewiesen eine bemerkenswerte Alltagstauglichkeit. Das vorgestellte Grundkonzept könnte eine Alternative bei der Entwicklung einfacher und kostengünstiger, aber dennoch gut einsatzfähiger bionischer Hände sein und zeigt einmal mehr, wie historische Ideen in die Gegenwart transferiert werden können.
A printed electronics technology has the advantage of additive and extremely low-cost fabrication compared with the conventional silicon technology. Specifically, printed electrolyte-gated field-effect transistors (EGFETs) are attractive for low-cost applications in the Internet-of-Things domain as they can operate at low supply voltages. In this paper, we propose an empirical dc model for EGFETs, which can describe the behavior of the EGFETs smoothly and accurately over all regimes. The proposed model, built by extending the Enz-Krummenacher-Vittoz model, can also be used to model process variations, which was not possible previously due to fixed parameters for near threshold regime. It offers a single model for all the operating regions of the transistors with only one equation for the drain current. Additionally, it models the transistors with a less number of parameters but higher accuracy compared with existing techniques. Measurement results from several fabricated EGFETs confirm that the proposed model can predict the I-V more accurately compared with the state-of-the-art models in all operating regions. Additionally, the measurements on the frequency of a fabricated ring oscillator are only 4.7% different from the simulation results based on the proposed model using values for the switching capacitances extracted from measurement data, which shows more than 2× improvement compared with the state-of-the-art model.
The separation of nitrogen and methane from hydrogen-rich mixtures is systematically investigated on a recently developed binder-free zeolite 5A. For this adsorbent, the present work provides a series of experimental data on adsorption isotherms and breakthrough curves of nitrogen and methane, as well as their mixtures in hydrogen. Isotherms were measured at temperatures of 283–313 K and pressures of up to 1.0 MPa. Breakthrough curves of CH4, N2, and CH4/N2 in H2 were obtained at temperatures of 300–305 K and pressures ranging from 0.1 to 6.05 MPa with different feed concentrations. An LDF-based model was developed to predict breakthrough curves using measured and calculated data as inputs. The number of parameters and the use of correlations were restricted to focus on the importance of measured values. For the given assumptions, the results show that the model predictions agree satisfactorily with the experiments under the different operating conditions applied.
Energy consumption for cooling is growing dramatically. In the last years, electricity peak consumption grew significantly, switching from winter to summer in many EU countries. This is endangering the stability of electricity grids. This article outlines a comprehensive analysis of an office building performances in terms of energy consumption and thermal comfort (in accordance with static – ISO 7730:2005 – and adaptive thermal comfort criteria – EN 15251:2007 –) related to different cooling concepts in six different European climate zones. The work is based on a series of dynamic simulations carried out in the Trnsys 17 environment for a typical office building. The simulation study was accomplished for five cooling technologies: natural ventilation (NV), mechanical night ventilation (MV), fan-coils (FC), suspended ceiling panels (SCP), and concrete core conditioning (CCC) applied in Stockholm, Hamburg, Stuttgart, Milan, Rome, and Palermo. Under this premise, the authors propose a methodology for the evaluation of the cooling concepts taking into account both, thermal comfort and energy consumption.
There is an increasing demand by an ever-growing number of mobile customers for transfer of rich media content. This requires very high bandwidth which either cannot be provided by the current cellular systems or puts pressure on the wireless networks, affecting customer service quality. This study introduces COARSE – a novel cluster-based quality-oriented adaptive radio resource allocation scheme, which dynamically and adaptively manages the radio resources in a cluster-based two-hop multi-cellular network, having a frequency reuse of one. COARSE is a cross-layer approach across physical layer, link layer and the application layer. COARSE gathers data delivery-related information from both physical and link layers and uses it to adjust bandwidth resources among the video streaming end-users. Extensive analysis and simulations show that COARSE enables a controlled trade-off between the physical layer data rate per user and the number of users communicating using a given resource. Significantly, COARSE provides 25–75% improvement in the computed user-perceived video quality compared with that obtained from an equivalent single-hop network.
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
This paper treats the interaction between acoustic modes and light (Brillouin scattering) in a single mode optical fibre. Different observed spectra of the Brillouin backscattering in several fibres have been already reported. In order to have a clear idea of the process, we made a simulation to be able to `draw' the theoretical Brillouin spectrum of an optical fibre and to identify the origin of the observed backscattered lines.
First, the model and the computation method used in our simulation are described. Second, the experimentally observed spectra of two real fibres are compared with their computed spectra. Real spectra and simulated spectra are in good agreement.
Our work provides an interesting tool to investigate the changes in the Brillouin spectrum when the input parameters (characteristics of an optical fibre) vary. This should give useful indications to people working on systems which use Brillouin backscattering.