Quasi‐Solid‐State Single‐Atom Transistors

The single‐atom transistor represents a quantum electronic device at room temperature, allowing the switching of an electric current by the controlled and reversible relocation of one single atom within a metallic quantum point contact. So far, the device operates by applying a small voltage to a control electrode or “gate” within the aqueous electrolyte. Here, the operation of the atomic device in the quasi‐solid state is demonstrated. Gelation of pyrogenic silica transforms the electrolyte into the quasi‐solid state, exhibiting the cohesive properties of a solid and the diffusive properties of a liquid, preventing the leakage problem and avoiding the handling of a liquid system. The electrolyte is characterized by cyclic voltammetry, conductivity measurements, and rotation viscometry. Thus, a first demonstration of the single‐atom transistor operating in the quasi‐solid‐state is given. The silver single‐atom and atomic‐scale transistors in the quasi‐solid‐state allow bistable switching between zero and quantized conductance levels, which are integer multiples of the conductance quantum G₀ = 2e²/h. Source–drain currents ranging from 1 to 8 µA are applied in these experiments. Any obvious influence of the gelation of the aqueous electrolyte on the electron transport within the quantum point contact is not observed.     

Willing and able to fake emotions: A closer examination of the link between emotional dissonance and employee well-being.

Emotional dissonance resulting from an employee's emotional labor is usually considered to lead to negative employee outcomes, such as job dissatisfaction and emotional exhaustion. Drawing on Festinger's (1957) cognitive dissonance theory, we argue that the relationship between service employees' surface acting and job dissatisfaction and emotional exhaustion is moderated by 2 aspects of a service worker's self-concept: the importance of displaying authentic emotions (reflecting the self-concept's self-liking dimension) and the employee's self-efficacy when faking emotions (reflecting the self-competence dimension). A survey of 528 frontline employees from a wide variety of service jobs provides support for the moderating role of both self-concept dimensions, which moderate 3 out of 4 relationships. Theoretical and practical implications are discussed from the perspectives of cognitive dissonance and emotional labor theories. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Photoluminescence and electroluminescence imaging of perovskite solar cells

Fast camera‐based luminescence‐imaging measurements on perovskite solar cells are presented. The fundamental correlation between the luminescence intensity and the open circuit voltage predicted by the generalised Planck law is confirmed, enabling various quantitative methods for the detection of efficiency‐limiting defects to be applied to this new cell structure. Interstinegly, it is found that this fundamental correlation is valid only for light‐soaked devices. Copyright © 2015 John Wiley & Sons, Ltd.     

Influence of plasma nitriding on hydrogen environment embrittlement of 1.4301 austenitic stainless steel

The aim of this work was to study if hydrogen environment embrittlement of DIN 1.4301 austenitic stainless steel can be suppressed by a nitrided surface. DIN 1.4301 was plasma nitrided in a N₂/H₂ discharge. Nitriding produced 3-layered structure consisting of a γ_N top layer, an intermediate γ/γ_C-layer and a diffusion layer. It is assumed that the γ_C phase was formed due to the decomposition of CO originating from the reactor walls and the subsequent incorporation of C into the material. The γ_C phase is characterized by distinct XRD peaks and carbon contents between 0.5 and 4 wt.% as well as nitrogen contents between 0.5 and 8 wt.%. Plastic deformation of the plasma nitrided specimen showed cracks and some delamination of the γ_N layer, whereas the γ/γ_C-layer behaved in a very ductile manner. Even at a plastic deformation of 35% no cracks or any other damage was visible. A tensile test in gaseous hydrogen showed severe embrittlement of the unnitrided steel and the nitrided steel with a γ_N layer. No cracks were observed in areas where just the γ/γ_C-layer was present.     

Effect of pre-treatment and hydraulic retention time on biohydrogen production from organic wastes

This study investigated the effect of pre-treatment and hydraulic retention time (HRT) on biohydrogen production from organic wastes. Various pre-treatments including thermal, base, acid, ultrasonication, and hydrogen peroxide were applied alone or in combination to enhance biohydrogen production from potato and bean wastewater in batch tests. All the pre-treated samples showed higher hydrogen production than the control tests. Hydrogen peroxide pre-treatment achieved the best results of 939.7 and 470 mL for potato and bean wastewater, respectively. Continuous biohydrogen production from sucrose, potato and bean wastewater was significantly influenced by reducing the HRT as 24, 18 and 12 h. Sucrose and potato showed similar behavior, where the hydrogen production rate (HPR) increased with decreasing the HRT. Optimum hydrogen yield results of 320 mL-H₂/g-VS (sucrose) and 150 mL-H₂/g-VS (potato) were achieved at HRT of 18 h. Bean wastewater showed optimum HPR of 0.65 L/L.d with hydrogen yield of 80 mL-H₂/g-VS at 24 h HRT.     

Stray current-induced corrosion in cathodic protection installations of steel-reinforced concrete structures: FEM study of the critical parameters

A wide range of parameters was investigated by numerical calculations concerning their impact on DC stray current corrosion of reinforced concrete (RC) structures. A simplified model geometry was used to extract the relevant parameters and their interaction in terms of stray current-affected structures. This study mainly focuses on RC structures that are fitted with cathodic protection installations. The findings reveal a complex interaction between the investigated parameters. The possible relevance of further parameters, which is not the subject of this study, was emphasised.