Filtern
Erscheinungsjahr
- 2016 (173) (entfernen)
Dokumenttyp
- Wissenschaftlicher Artikel (64)
- Teil eines Buches (Kapitel) (26)
- Konferenzveröffentlichung (25)
- Beitrag zu einer (nichtwissenschaftlichen) Zeitung oder Zeitschrift (18)
- Buch (Monographie) (17)
- Lehrmaterial (11)
- Rezension (6)
- Bericht (5)
- Sonstiges (1)
Volltext vorhanden
- nein (173) (entfernen)
Schlagworte
- Empirische Methoden (2)
- Energiepolitik (2)
- Erneuerbare Energien (2)
- Fachjournalismus (2)
- Kommunikationswissenschaft (2)
- Rechtswissenschaft (2)
- Wissenschaftliches Arbeiten (2)
- open quantum systems (2)
- carbon nanofibers, platinum electrodeposition, ele ctrochemical surface area (1)
- Besondere Ausgleichsregelung (1)
- Betriebswirtschaft (1)
- Biomedical monitoring, Hospitals, Electrocardiography, Wireless communication, Patient monitoring, Wireless sensor networks (1)
- Branding (1)
- CRM (1)
- Cavitation; Corrosion; Laser remelting; Self-fluxing alloys; Stellite 6 (1)
- Compliance (1)
- Corporate Governance (1)
- Corporate Governance Codex (1)
- Current Pulses (1)
- Datenanalyse (1)
- Emissionshandel (1)
- Ethik (1)
- Flat-Channel (1)
- Geldpolitik (1)
- Geldschöpfung (1)
- Handelsbilanz (1)
- Hochschuldidaktik (1)
- Hydraulic compression, Carbon Nano Fibers, PEM Fuel Cells, Catalyst utilization (1)
- Implantat (1)
- Journalismus (1)
- Juristisches Studium (1)
- Kapitalverkehrsbilanz (1)
- Kernspintomografie (1)
- Kundenmanagement (1)
- Launcher (1)
- Medienforschung (1)
- Negativzins (1)
- PEM fuel cell electrocatalysts, Carbon nanofibers, Oxygen plasma activation, Pulsed electroplating. (1)
- PEM fuel cells; electrode preparation; carbon nanofibers; in-situ performance test (1)
- Projektabwicklung (1)
- Redaktion (1)
- Schuldrecht (1)
- Sinusoidal (1)
- Spondylodese (1)
- Stellite 6; HVOF-spraying; Laser remelting; Cavitation erosion; Coatings (1)
- Thermal Stress (1)
- Vertrag (1)
- Vertragsrecht (1)
- Wachstum (1)
- Wechselkurs (1)
- Wirtschaft (1)
- carbon nanofibers, platinum electrodeposition, electrocatalysts (1)
- conical intersection (1)
- demagnetization cooling (1)
- didaktische Qualifizierung (1)
- ethics (1)
- expert interviews (1)
- infrared heating panel (1)
- international comparative study (1)
- media accountability (1)
- nonadiabatic dynamics (1)
- nonequilibrium quantum transport (1)
- offene Volkswirtschaft (1)
- role identity (1)
- watchblogs (1)
- Überschussliquidität (1)
Institut
- Wirtschaftsrecht (80)
- Informatik und Kommunikation (20)
- Institut für Internetsicherheit (14)
- Westfälisches Institut für Gesundheit (13)
- Westfälisches Energieinstitut (11)
- Strategische Projekte (9)
- Wirtschaft und Informationstechnik Bocholt (8)
- Elektrotechnik und angewandte Naturwissenschaften (6)
- Institut für Innovationsforschung und -management (4)
- Maschinenbau und Facilities Management (2)
- Wirtschaft Gelsenkirchen (2)
- Maschinenbau Bocholt (1)
- Wirtschaftsingenieurwesen (1)
For this study gas diffusion electrodes (GDE) with low platinum loading are prepared for the application as anode in polymer electrolyte membrane fuel cell (PEMFC) systems based on hydraulic compression. As catalyst support material, carbon nanofibers (CNF) are investigated because of their high specific surface area and high graphitization degree. The electrode preparation is optimized by an economic and environmental friendly pre-treatment process in oxygen plasma. For GDE manufacture an ink containing oxygen plasma activated CNFs as well as hydrophilic polymer is used. After spray coating of this CNF ink on a graphitic substrate, platinum is deposited using the pulse plating technique. Preliminary results showed a considerable improvement of CNF dispersibility as well as an increased amount and an optimized morphology of the deposited platinum. Morphology and microstructure are observed by scanning electron microscopy as well as transmission electron microscopy. Platinum loading is determined by thermogravimetric analysis to be in the range of 0.01 mg cm-2 to 0.017 mg cm-2. Furthermore, MEAs are prepared from these GDEs and testing is performed in a novel modular fuel cell test stack based on hydraulic compression. Technical information about stack design and functions is given in this work.
Under ambient conditions, almost all metals are coated by an oxide. These coatings, the result of a chemical reaction, are not passive. Many of them bind, activate and modify adsorbed molecules, processes that are exploited, for example, in heterogeneous catalysis and photochemistry. Here we report an effect of general importance that governs the bonding, structure formation and dissociation of molecules on oxidic substrates. For a specific example, methanol adsorbed on the rutile TiO2(110) single crystal surface, we demonstrate by using a combination of experimental and theoretical techniques that strongly bonding adsorbates can lift surface relaxations beyond their adsorption site, which leads to a sig- nificant substrate-mediated interaction between adsorbates. The result is a complex super- structure consisting of pairs of methanol molecules and unoccupied adsorption sites. Infrared spectroscopy reveals that the paired methanol molecules remain intact and do not depro- tonate on the defect-free terraces of the rutile TiO2(110) surface.
Biofunktionalisierung von Titanimplantaten mit einem Multilayersystem aus BMP-2 und Fibronektin
(2016)
Buchbesprechungen
(2016)
The wireless data logger system “Cor/log® BAN BT” (CL) allows seamless 24/7 monitoring of relevant vital sign parameters. CL covers the entire period of acute point of care inside the hospital and the recovery period, when first mobility is achieved and when the patient is released into an ambulatory or homecare environment. The CL records the relevant vital signs such as ECG, respiration, pulse oximetry with plethysmogram and movement. The vital data collected with the CL data logger is saved on a memory card for further analysis and is simultaneously transmitted in real-time to a telemedicine server via a smartphone or tablet. The smartphone also provides GPS location information. In addition Cor/log View, an Android Application for viewing recorded vital sign data originating from the CL, was developed. CL has also a connector to the generic MedM health cloud. MedM is a generic patient data management system (PDMS) consisting of a cloud portal and a mobile health app. The app runs on Android, iOS and Windows. The app can connects wirelessly to the CL physiologic monitor and stores the vital signs in the cloud.
Datenanalyse beim CRM
(2016)
Kultureinrichtungen als Arbeitgeber sehen sich zunehmend veränderten Rahmenbedingungen der Mitarbeitergewinnung und -bindung gegenüber, die sich aus mehreren gesellschaftlichen Megatrends ergeben. Zentral sind dabei zum einen der demografische Wandel und die damit einhergehende Überalterung der Arbeitnehmer, zum anderen geänderte Wertvorstellungen und Arbeitsmotive der jüngeren Arbeitnehmergeneration, der sogenannten „Generation Y“. Beides hat weitreichende Implikationen für das Recruiting und die dauerhafte Bindung von Mitarbeitern in zahlreichen Branchen an das jeweilige Unternehmen. Vorgestellt werden im folgenden Beitrag die Ergebnisse einer Studie, die zum einen Arbeitsmotivation und -zufriedenheit von Beschäftigten im Kultursektor untersucht hat und dabei den Fokus auf Wert- und Arbeitshaltungen der Generation Y gelegt hat. Zum anderen wurden die Bedeutung der Rahmenarbeitsbedingungen erhoben, insbesondere die Rolle der Führung sowie von Flexibilität am Arbeitsplatz.
Carbon Nanofibers (CNF) are considered to be a promising catalyst support material due to their unique characteristics, excellent mechanical, electrical and structural properties, high surface area and nevertheless, good interaction with metallic catalyst particles. The possibility of preparing CNF decorated with platinum by an electrochemical method was tested, using a hexachloroplatinic bath solution. The experiments were carried out with the aid of a Potentiostat/Galvanostat Ivium Technologies Vertex, in a three – electrode cell. The aim of the present work was to determine the electrochemical surface area (ECSA) of the CNF-Pt catalysts in relation to the functionalization treatment of fibers, using an electrochemical method. ECSA for different functionalized CNF-Pt catalysts was determined by cyclic voltammetry in 0.5 M H2SO4 solution. The highest active surface of platinum was obtained for the samples with CNF functionalized by plasma treatment using 80 W for 1800 s. The obtained results correlate very well with the particles size and distribution of platinum, revealed by scanning electron microscopy (SEM) and the quantity of deposited platinum determined by thermo gravimetrical analysis (TGA) respectively. Cyclic voltammetry (CV) has been proven to be a suitable method for estimation of the ECSA of the electrocatalysts.
Die Zeit nach dem Passwort. Handhabbare Multifaktor-Authentifizierung für ein gesundes Eco-System
(2016)
When an open quantum system is driven by an external time-dependent force, the coupling of the driving to the central system is usually included, whereas the impact of the driving field on the bath is neglected. We investigate the effect of a quantum bath of linearly driven harmonic oscillators on the relaxation dynamics of a quantum two-level system which is not directly driven. In particular, we calculate the frequency-dependent response of the system when the bath is subject to Dirac and Gaussian driving pulses. We show that a time-retarded effective force on the system is induced by the driven bath which depends on the full history of the perturbation and the spectral characteristics of the underlying bath. In particular, when a structured Ohmic bath with a pronounced Lorentzian peak is considered, the dynamical response of the system to a driven bath is qualitatively different than that of the undriven bath. Specifically, additional resonances appear which can be directly associated with a Jaynes-Cummings-like effective energy spectrum.
In the polymer electrolyte membrane fuel cells (PEMFC) state of the art, rare and expensive platinum group metals (PGM) or PGM alloys are used as catalyst material. Reduction of PGMs in PEMFC electrodes is strongly required to reach cost targets for this technology. An optimal catalyst utilization is achieved in case of nano-structured particles supported on carbon material with a large specific surface area. In this study, graphitic material, in form of carbon nanofibers (CNF), is decorated with Pt particles, serving as catalyst material for PEMFC electrodes with low Pt loading. As a novelty, the effect of oxygen plasma treatment of CNFs previously to platinum particle deposition has been studied. Electrodes are investigated in respect of the optimal morphology, microstructure as well as electrochemical properties. Therefore, samples are characterized by means of scanning electron microscopy combined with energy dispersive X-ray analysis, transmission electron microscopy, thermogravimetry, X-ray diffraction as well as X-ray fluorescence analysis. In order to determine the electrochemical active surface area of catalyst particles, cyclic voltammetry has been performed in 0.5 M sulphuric acid. Selected samples have been investigated in a PEMFC test bench according to their polarization behavior.
Eigentum verpflichtet
(2016)
Empirische Methoden
(2016)
This paper aims to compare cobalt-based (type Stellite 6) and nickel-based self-fluxing alloys (type NiCrBSiMo) regarding both their cavitation erosion resistance and corrosion resistance. The two types of protective layers were thermally sprayed onto a substrate of martensitic stainless steel. In order to improve the layers' characteristics and their metallurgical bonding to the substrate, the Stellite 6 coating was laser remelted, while the NiCrBSiMo coating was treated by flame fusion. The cavitation erosion resistance of the two materials was evaluated by measurements of the mean depth of erosion developed during a testing period of 165 minutes, using a 20 kHz ultrasonic vibrator at a peak-to-peak amplitude of 50 μm. In addition, the corrosion resistance of the layers was assessed by potentiodynamic corrosion tests carried out in H2SO4 + NaCl solution at room temperature, using calomel as reference electrode. In order to highlight the differences regarding the behaviour of the two protective materials, the authors also carried out microstructural investigations of the layers before and after exposure to cavitation and corrosion. The investigations showed that both types of layers can provide improved protection of the martensitic stainless steel substrate against cavitation, whilst the NiCrBSiMo coating additionally confers significantly increased resistance to corrosion.
We present a scheme for cooling a vibrational mode of a magnetic molecular nanojunction by a spin-polarized charge current upon exploiting the interaction between its magnetic moment and the vibration. The spin-polarized charge current polarizes the magnetic moment of the nanoisland, thereby lowering its energy. A small but finite coupling between the vibration and the magnetic moment permits a direct exchange of energy such that vibrational energy can be transferred into the magnetic state. For positive bias voltages, this generates an effective cooling of the molecular vibrational mode. We determine parameter regimes for the cooling of the vibration to be optimal. Although the flowing charge current inevitably heats up the vibrational mode via Ohmic energy losses, we show that due to the magnetomechanical coupling, the vibrational energy (i.e, the effective phonon temperature) can be lowered below 50% of its initial value, when the two leads are polarized anti-parallel. In contrast to the cooling effect for positive bias voltages, net heating of the vibrational mode occurs for negative bias voltages. The cooling effect is enhanced for a stronger anti-parallel magnetic polarization of the leads, while the heating is stronger for a larger parallel polarization. Yet, dynamical cooling is also possible with parallel lead alignments when the two tunneling barriers are asymmetric.
Foliensatz Branding
(2016)
Gelingendes Projektmanagement in der Schule am Beispiel der Potenzialanalyse in der achten Klasse
(2016)
Handbuch Sporttourismus
(2016)
Bereits im April 2012 wurde im HZwei Magazin ein Stackkonzept für PEM-Brennstoffzellen vorgestellt, bei dem im Gegensatz zu der heute üblichen bipolaren Zellenanordnung mit mechanischer Verpressung Einzelzellen über ein Hydraulikmedium verpresst werden. Die Vorteile der homogenen Verpressung und Temperierung der Zellen wurden hierbei herausgestellt. Zwischenzeitlich ist basierend auf diesem Ansatz das Labormuster eines PEM-Elektrolyseurs entwickelt worden, bei dem der produzierte Wasserstoff oder auch der Sauerstoff mit hohen Ausgangsdrücken, z.B. auf einem für Power-2-Gas-Anlagen günstigem Druckniveau, direkt bereitgestellt werden kann.
This work deals with the preparation and investigation of PEM fuel cell electrodes, which are obtained using graphene related material (GRM) serving as catalyst support for platinum nanoparticles. Applied GRM are used for the preparation of suspensions in four distinct mixing ratios. Two sorts of GRM have been investigated: carbon nanofibers (CNF) and graphene oxide (GO). Utilized CNFs provide a superior graphitization degree of about 100%, which leads to both high corrosion resistance and low ohmic resistance in PEM fuel cells.
For electrode preparation a GRM containing layer serving as catalyst support is applied onto a gas diffusion layer (GDL). Prior to GRM suspension and deposition onto a GDL, the graphene structures are functionalized by plasma treatment. Due to this step, an improved hydrophilic behavior for facilitating suspension preparation is achieved. In addition, a subsequent platinum nanoparticle deposition by pulsed electrodeposition process is optimized.
In this experimental work polymer electrolyte membrane fuel cell (PEMFC) electrodes are analysed, which are prepared by the use of two sorts of carbon nano fibres (CNF) serving as support material for platinum nano particles. Those CNFs, which are heat treated subsequently to their production, have a higher graphitisation degree than fibres as produced. The improved graphitisation degree leads to higher electrical conductivity, which is favourably for the use in PEMFC electrodes. Samples have been analysed, in order to determine graphitisation degree, electrical conductivity, as well as morphology and loading of the prepared electro catalyst. Membrane electrode assemblies manufactured from prepared electrodes are analysed in-situ in a PEM fuel cell test environment. It has been determined that power output for samples containing CNFs with higher graphitisation degree is increased by about 13.5%.
Intelligente Helfer als persönlicher Assistent. Wie sicher und vertrauenswürdig sind Roboter?
(2016)
Interessengerechte Lösung gesucht! Der BGH zu Verlegerbeteiligungen an Ausschüttungen der VG Wort
(2016)
Kommunikationswissenschaft
(2016)