Polar pollutants in municipal wastewater and the water cycle: Occurrence and removal of benzotriazoles

1H-benzo-1,2,3-triazole (BTri) and its methylated analogues (tolyltriazole, TTri) are corrosion inhibitors used in many industrial applications, but also in households in dishwashing agents and in deicing fluids at airports and elsewhere. BTri and one of the TTri-isomers (4-TTri) are typical examples of polar and poorly degradable trace pollutants. Benzotriazole elimination in four wastewater treatment plants (WWTP) in Berlin ranged from 20 to 70% for 5-TTRi over 30 to 55% for BTri to insignificant for 4-TTri. WWTP effluent concentrations were in the range of 7-18 μg/L of BTri, 1-5 μg/L of 4-TTri and 0.8-1.2 μg/L of 5-TTri. BTri and 4-TTri proved to be omnipresent in surface waters of the rivers Rhine and Elbe with concentrations increasing from <0.05 μg/L to around 0.5 μg/L of BTri and 0.2-0.5 μg/L of 4-TTri over 600-700 km. Bank filtration is an important process to generate raw water for drinking water production from surface waters. Even after residence times of several months BTri and 4-TTri were determined in concentrations of a few hundred ng/L in bank filtration water. Isotherm data from batch experiments indicate that activated carbon filtration should be suitable to avoid intrusion of TTri into drinking water in partially closed water cycles. For BTri, however, sorption to activated carbon appears to be too weak and ozonation may be mandatory to remove it from raw waters.     

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.     

Iron oxide-based honeycomb catalysts for the dehydrogenation of ethylbenzene to styrene

Corning has recently developed a novel extrusion method to make bulk transition metal oxide honeycomb catalysts. One area of effort has been iron oxide-based catalysts for the dehydrogenation of ethylbenzene to styrene, a major chemical process that yields worldwide 20 MM tons/yr. In industry, the monomer is synthesized mostly in radial-flow fixed-bed reactors. Because of the high cross-sectional area for flow and shallow depth of the catalyst bed in these reactors, low reactor pressure gradients are maintained that favors the yield and selectivity for styrene formation. However, the radial-flow design has inherent detractions, including inefficient use of reactor volume and large temperature gradients that decrease catalyst service life. The overall economics of the process can be improved with parallel-channel honeycomb catalysts and axial flow reactors. The simple axial flow design of honeycomb catalysts provides low-pressure drop, while making more efficient use of reactor volume, with better heat and mass transfer characteristics compared to a conventional radial packed bed. An important part of this concept is the ability to fabricate a wide family of dehydrogenation catalyst compositions into honeycombs with the requisite chemical, physical, mechanical, and catalytic properties for industrial use. The ethylbenzene dehydrogenation (EBD) honeycomb catalysts developed by Corning have compositions similar to those commonly used in industry and are prepared with the same catalyst and promoter precursors and with similar treatments.

However, to enable extrusion of catalyst precursors into honeycomb shapes, especially at cell densities above 100 cell/in.², Corning’s process compensates for the high salt concentrations and the high pH of the batch material that would otherwise prevent or impede honeycomb extrusion. The improved rheological characteristics provide the necessary plasticity, lubricity, and resiliency for honeycomb extrusion with sufficient binder strength needed before calcination to the final product. Iron oxide-based honeycombs after calcination are strong and possess macroporosity and high surface area. In bench-scale testing, particular honeycomb catalyst compositions exhibited 60–76% ethylbenzene conversion with styrene selectivity of 95–91%, respectively, under conventional reaction conditions without apparent deactivation or loss of mechanical integrity.     

More Than Stories With Buttons: Narrative,Mechanics, and Context as Determinants of Player Experience in Digital Games

Recent research has attempted to describe meaningful experiences with entertainment media that go beyond hedonic enjoyment. Most of this research focuses on noninteractive media, such as film and television. When applied to digital games, however, such research needs to account for not only the content of the medium, but also the unique dimensions of digital games that distinguish them from noninteractive media. Experiences with digital games are shaped by the game mechanics that define the users' interaction with game content, as well as by the opportunities for social interaction that many games offer. We argue that the complex interplay of these dimensions (narrative, mechanics, and context) facilitates or inhibits meaningful user experiences in ways that are unique to digital games.     

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)     

Polymer-based fabrication techniques for enclosed microchannels in biomedical applications

Investigations and analyses of body fluids like serum or whole blood are essential tasks in biomedical research in order to understand and diagnose diseases, to conduct pharmacological tests or to culture cells. Therefore, microfluidic systems provide a favorable tool for processing fluid samples as they allow downscaling of sample volumes and handling of single fluid components such as cells or proteins. For this reason, we present simple fabrication techniques for microchannel systems using polymer materials only. The demonstrated fabrication procedures are based on combinations of acrylic glass and the photo resists SU-8 and PerMX3020. On the one hand, these materials are low-priced compared to conventional silicon or glass. On the other hand, they have not shown any interaction with blood or other cell suspensions within the frame of our study. Furthermore, their transparency guarantees an easy observability of all processes within the system. Depending on the channel dimensions, different adhesion bonding techniques for closing of the systems are applied, whereas the fluidic interfaces are included by mechanical drilling. Summing up, we provide complete fabrication processes for fluidic systems which are simpler and more cost-effective than conventional methods and yet cope with all essential requirements for microfluidic applications.     

Sicherung der Netzneutralität

Die Geschichte des Internets ist eine Erfolgsgeschichte. Dieser Erfolg beruht u.a. auf einer neutralen Datenübermittlung, die dadurch gekennzeichnet ist, dass Netzbetreiber Datenpakete von und an ihre Kunden unver?ndert und gleichberechtigt übertragen, unabh?ngig davon, woher diese stammen und welche Anwendungen die Pakete generiert haben. In jüngster Zeit werden Forderungen nach Verkehrsregelungen im Internet lauter. Begründet wird diese Initiative mit einer drohenden Netzüberlastung, die durch die wachsende Popularit?t von Videoangeboten wie YouTube oder Streaming-Angeboten wie Hulu entsteht. Kritiker befürchten, dass durch den Einsatz neuer Netzwerkmanagementtechniken die Innovationsoffenheit und die freie Kommunikation im Internet gef?hrdet werden. Der Beitrag analysiert die M?glichkeiten und Grenzen der Gew?hrleistung von Netzneutralit?t durch das deutsche Telekommunikations- und Medienrecht.     

Evaluation of polycaprolactone − poly‐D,L‐lactide copolymer as biomaterial for breast tissue engineering

The potential of the copolymer polycaprolactone‐co‐ poly‐d ,l ‐lactic acid (PCLLA ) as a biomaterial for scaffold‐based therapy for breast tissue engineering applications was assessed. First, the synthesized PCLLA was evaluated for its processability by means of additive manufacturing (AM ). We found that the synthesized PCLLA could be fabricated into scaffolds with an overall gross morphology and porosity similar to that of polycaprolactone. The PCLLA scaffolds possessed a compressive Young's modulus (ca 46 kPa ) similar to that of native breast (0.5 ? 25 kPa ), but lacked thermal stability and underwent thermal degradation during the fabrication process. The PCLLA scaffolds underwent rapid degradation in vitro which was characterized by loss of the scaffolds' mechanical integrity and a drastic decrease in mass‐average molar mass (M _w) and number‐average molar mass (M _n) after 4 weeks of immersion in phosphate buffer solution maintained at 37 °C. The tin‐catalysed PCLLA scaffold was also found to have cytotoxic effects on cells. Although the initial mechanical properties of the PCLLA scaffolds generally showed potential for applications in breast tissue regeneration, the thermal stability of the copolymer for AM processes, biocompatibility towards cells and degradation rate is not satisfactory at this stage. Therefore, we conclude that research efforts should be geared towards fine‐tuning the copolymer synthesizing methods. © 2016 Society of Chemical Industry