Efficiency enhancement of a dielectric barrier plasma discharge by dielectric barrier optimization

The characteristic feature of a dielectric barrier discharge (DBD) is the dielectric barrier placed between the electrodes. In the present work, the influence of the dielectric barrier to the properties of a DBD in air was investigated. Spectroscopic characterization of the DBD and electrical measurements were carried out. It was shown that the efficiency of a DBD can be considerably improved by optimizing the dielectric barrier. The dielectric material should possess an appropriate relative permittivity and thickness. For thin dielectric barriers, a high secondary emission coefficient becomes important. Additionally, the use of only one dielectric barrier is advantageous.     

In‐line analysis of the influence of monomeric and oligomeric hindered amine on the hydrolysis of polycarbonate in a PC/ABS blend

The polycarbonate/polyacrylonitrile butadiene styrene (PC/ABS) blends lose mechanical properties when exposed to outdoor conditions. This is due to the ultraviolet (UV) induced photo‐oxidation of the PC phase and the polybutadiene portion of the ABS. It is known that ABS can be stabilised against terrestrial light by the use of hindered amine in combination with a UV absorber. However, such hindered amine cannot be used when PC is present in a multi component polymer blend. The hydrolysis of PC is accelerated when a small amount of hindered amine light stabilisers (HALS) is incorporated in the resin and is exposed to elevated temperature. In this article the effect of monomeric and oligomeric hindered amine on the hydrolysis of PC during the compounding of PC/ABS blend in a twin screw extruder at 240°C is observed by means of in‐line UV‐vis spectroscopy. Tinuvin 765 was used as monomeric hindered amine and Tinuvin 622 as oligomeric hindered amine. The molecular weight of the compounded sample was determined by gel permeation chromatography (GPC) and the rheological properties were observed using an online viscometer. It was found that the extent of hydrolysis induced by the oligomeric hindered amine is less compared to monomeric amine. It was also observed that polymeric hindered amine imparts better dispersion of the ABS phase into the polymer blend. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Perceiving speed—The color can matter

This study focuses on examining color effects of perceived speed in an individual noncompetitive sport context, treadmill running. In addition, the presence of individual trends for color effects are inspected by observing the connection of color effects in a sport‐specific video rating task with those found in an individual color association task. For this, 32 participants rated the perceived running speed of 48 videos depicting runners on a treadmill at seven different speed settings. Furthermore, participants rated a range of additional sport‐specific performance parameters. The runners in the video were shown wearing either a red, blue, or gray jersey, gray being used to strengthen the cover story. As a secondary task, the participants performed a modified Stroop task to assess implicit color associations. The results showed a significant color effect for speed; runners depicted in red were perceived as running at higher speeds compared to blue. No significant color effects were found for the other sport‐specific parameters. Finally, there was no significant covariate effect of the modified Stroop task for the speed perception color effect. These findings indicate that, in situations in which speed must be judged, red might be perceived as going faster.     

Einfluß von Carboxymethylcellulose auf das Verhalten von Tonsuspensionen unter besonderer Berücksichtigung des Tiefbohrsektors

The function of drilling fluid includes the removal of the cuttings from the bore hole, the supporting of the hole wall, the cooling of the bit, and the maintenance of the hydrostatic equality with the formation pressure. The clay suspension preferred to employ these purposes possess adequate flow limits and gel strengths, the water retensivity however is insufficient. With the addition of carboxymethylcellulose the dispersion of clay in water and the water retensivity are improved. In the present publication, the influence of carboxymethylcellulose in clay-water and sodiumchlorid-saturated clay-water suspension on the rheological properties and the water retensivity are investigated.