Pervaporation of high boilers using heated membranes

Hydrophobic polymer membranes for organic pervaporation from aqueous-organic feed solutions are stabilized against swelling distortion by incorporating a woven fabric near the non-swelling downstream interface. When using electrically conducting metal wire fabric, the membrane may be heated, thereby reversing the temperature gradient across the membrane. An apparatus for pervaporation using electrically heated membranes is described, and test results on pervaporation of high boilers (phenol, benzoic acid, γ-decalactone) as a function of power supplied are presented.     

Influences of motives to play and time spent gaming on the negative consequences of adolescent online computer gaming

In this study we examined the relation between gaming-time, motives to play, and negative consequences due to playing MMORPGs. A total of 7757 Swedish adolescents (3872 boys and 3885 girls) between 13 and 18 years of age completed a questionnaire during class hours. Results indicated that time spent on gaming was associated with negative consequences. This relation was further explained by motives to play. Gaming for fun and social motives were associated with a reduced risk whereas gaming to escape, to gain status, or due to demands from others were associated with an increased risk of negative consequences. Motives to play should be considered as a prime indicator for negative consequences, even more than time spent gaming. Implications of these findings for future research are discussed.     

Towards a seamless integration between process modeling descriptions at business and production levels: work in progress

To fulfill increasing requirements in the manufacturing sector, companies are facing several challenges. Three major challenges have been identified regarding time-to-market, vertical feedback loops, and level of automation. Grafchart, a graphical language aimed for supervisory control applications, can be used from the process-planning phase, through the implementation phase and all the way to the phase for execution of the process control logics, on the lower levels of the automation triangle along the life cycle axis. This work in progress examines that the same process-based engineering approach can be used on the higher levels of the automation triangle along the enterprise axis interconnecting both axes. By splitting the execution engine and the visualization engine of Grafchart various different visualization tools could potentially be used, however connected by the shared Grafchart semantics. Traditional Business languages (e.g. BPMN) could therefore continue to be used for the process-planning phase whereas traditional production languages (e.g. Grafchart or other sequential function charts-like languages) could be used for the execution. Since they are connected through the semantics, advantages regarding the three identified challenges could be achieved: time-to-market could be reduced, the time delays in the vertical feedback loops could be reduced by Key Performance Indicator visualization and eventing, and the level of automation could be increased.     

The use of immobilized Candida antarctica lipase for simultaneous supercritical fluid extraction and in-situ methanolysis of cis-vaccenic acid in milkweed seeds

cis-Vaccenate was determined in milkweed (Ascelpias) seed employing supercritical fluid extraction (SFE) with in-situ enzymatic methanolysis. Candida antarctica lipase type B immobilized onto two different types of carrier materials—a hydrophobic polymer (Novozyme 435) and a silica-based material (NovoSample 40013)—was investigated. Several SFE parameters were investigated to find the optimal conditions, including extraction time, temperature, methanol concentration, and water level. It was shown that 90 min of dynamic extraction/reaction time was required, and that the optimal methanol and water concentrations differed for the two enzyme preparations studied. Overall, Novozyme 435 demonstrated the fastest reaction kinetics and consistently gave the highest vaccenate yields. The optimized methodology was applied on 15 species of milkweed seeds, giving an average recovery of 105±7% when compared to results obtained using a conventional methodology. The average relative standard deviations were 8% for the enzyme-based method and 4% for the reference method. The proposed methodology was faster, was less laborious, and consumed less organic solvent than the reference method. Hence, SFE with in-situ enzymatic methanolysis is a promising methodology for the analysis of FA in oilseeds.     

Very High Cycle Fatigue of Two Ductile Iron Grades

Two ductile iron grades, EN‐GJS‐600‐3 a ferritic–pearlitic grade, and EN‐GJS‐600‐10 a silicon strengthened ferritic nodular iron grade, are studied in the very high cycle fatigue range using a 20 kHz ultrasonic test equipment. Fatigue strengths and SN‐curves are achieved, and fracture surfaces and microstructures are investigated. The ferritic grade with higher ductility displays a lower fatigue strength at 10⁸ load cycles than the ferritic–pearlitic grade, 142 and 167 MPa, respectively. Examination of fracture surfaces shows that fatigue failures are controlled by micropores in both of the ductile iron grades, while the graphite nodule distributions do not seem to influence the difference in fatigue strengths. Prediction of the fatigue strengths, using a model for ductile iron proposed by Endo and Yanase, indicates a large potential for improvement in particular for the ferritic grade.     

Sensitivity calculations of tunnel fires using CFD

Detailed numerical simulations of fires in road tunnels were carried out using the CFD code JASMINE. Fire tests performed in the Ofenegg tunnel have also been validated. A parametric study of fires in an arbitrary 300-m-long tunnel was made, in which the influence of fire size, tunnel width, ventilation and ground slope was investigated. The movement of hazardous temperature and smoke regions as a function of time was calculated to vestigate escape possibilities from the tunnel in case of fire.     

Moving home again? Never! The locational choices of graduates in Sweden

Two major challenges in Europe’s rural areas are an aging population and the diminishing share of human capital. While this pattern has been occurring for a long time, the effects are becoming acutely visible and impactful. The long-term loss of younger individuals has in many ways “drained” the labor market and the economic market power of rural areas. This is the context of our research: the locational choice of university graduates from an urban–rural perspective. Using micro data covering the entire Swedish population, we identify all university graduates from the year 2001. We analyze them with respect to whether they live in a rural or urban region before starting university and where they live after graduation at two points in time: 5 and 10 years. We use a series of multinomial logit regressions to determine what factors affect their short-term and long-term choices of location. We find that having children is one of the most influential factors for moving back home after graduation, irrespective of type of region. We find only minor differences between the two time perspectives.     

Large signal modelling of GaAs/AlGaAs HBT's with separation of the surface recombination current

The effects of surface recombination on an AlGaAs/GaAs HBT have been investigated. Studies of Gummel-plots for devices with different sized base emitter junctions made it possible to separate the surface recombination from the bulk current. An extension of the Gummel–Poon model that includes this surface recombination current is suggested. The large-signal performance was evaluated by two methods, power spectrum characteristics and by design and characterization of a power amplifier. For these two measurement set-ups, measured data was compared with simulations of the model both including and excluding the surface recombination current. It is clearly seen that without including the surface recombination current, it is impossible to correctly represent the large-signal performance. The model is also verified with DC characteristics and S-parameters.