Thermodynamic Model of a Solar Receiver for Superheating of Sulfur Trioxide and Steam at Pilot Plant Scale

Within the European research project SOL2HY2, key components for a solar hybrid sulfur cycle are being developed and demonstrated at pilot scale in a real environment. Regarding the thermal portion, a plant for solar sulfuric acid decomposition is set up and initially operated at the research platform of the DLR Solar Tower in Jülich, Germany. One major component is the directly irradiated volumetric receiver, superheating steam and SO3 coming from a tube-type evaporator to above 1000 °C. At the design flow rate of sulfuric acid (50%-wt.) of 1 l/min, a nominal solar power of 57 kW is required at the receiver. With a flat ceramic absorber made from SiC and a flat quartz glass window, the design is based on lab scale reactors successfully demonstrated at the solar furnace of the German Aerospace Centre (DLR) in Cologne, Germany. A flexible lumped thermodynamic tool representing the receiver, compiled to assess different configurations, is presented in detail. An additional raytracing model has been established to provide the irradiation boundaries and support the design of a conical secondary concentrator with an aperture diameter of 0.6 m. A comparison with first experimental data (up to 65% nominal power), obtained during initial operation, indicates the models to be viable tools for design and operational forecast of such systems. With a provisional method to account for the efficiency of the secondary concentrator, measured fluid outlet temperatures (up to 1000 °C) are predicted with deviations of ±60 °C. Respective absorber front temperatures (up to 1200 °C) are under-predicted by 100-200 °C, with lower deviations at higher mass flows. The measured window temperature (up to 700 °C) mainly depends on the absorber front temperature level, which is well predicted by the model

Paraguai e as complexidades de uma nação bilíngue: A contradição da língua guarani como símbolo nacional e a sua condição de diglossia /

Paraguay es uno de los únicos países en Sudamérica que posee dos idiomas oficiales. El guaraní es uno de ellos y conforma un pilar de la identidad de los paraguayos. Sin embargo, el uso del guaraní parece disminuir progresivamente. Aparentemente, el gobierno y las actitudes de los hablantes no favorecen su uso en la sociedad, Por lo tanto, en esta investigación se pretende identificar cuál es el vínculo entre el aprecio que los paraguayos confiesan sentir hacia el guaraní y—contradictoriamente—el desprestigio lingüístico que la mayoría atribuye a la lengua vernácula

Paraguai e as complexidades de uma nação bilíngue: A contradição da língua guarani como símbolo nacional e a sua condição de diglossia /

Paraguay es uno de los únicos países en Sudamérica que posee dos idiomas oficiales. El guaraní es uno de ellos y conforma un pilar de la identidad de los paraguayos. Sin embargo, el uso del guaraní parece disminuir progresivamente. Aparentemente, el gobierno y las actitudes de los hablantes no favorecen su uso en la sociedad, Por lo tanto, en esta investigación se pretende identificar cuál es el vínculo entre el aprecio que los paraguayos confiesan sentir hacia el guaraní y—contradictoriamente—el desprestigio lingüístico que la mayoría atribuye a la lengua vernácula

A multicenter controlled study for dementia prevention through physical, cognitive and social activities – GESTALT-kompakt

Prevention of dementia is a public health priority. Physical activity (PA) can reduce the risk of dementia, but the majority of people remain sedentary. We conducted a multicenter controlled study with older adults (60+ years). We hypothesized that an evidence-based PA intervention – GEhen, Spielen und Tanzen Als Lebenslange Tätigkeiten – kompakt [walking, playing and dancing as lifelong activities-compact] (GESTALT-kompakt) – would lead to significantly larger improvements in PA levels (step counts/Fitbit Zip™), cognitive functions (DemTect) and social activities (Social Activity Log), compared to an active control group. Data were collected at baseline and after 3 and 12 months. The intervention group received a 12-week (1/week) multimodal and multicomponent PA program, which combined PA with cognitive and social activities. The control group received either regular gymnastics or cognitive training (1/week). A mixed linear model was chosen for analysis. A total of 87 older individuals were recruited in the GESTALT-kompakt study (68 females, average age =76.0 years, SD ±9.2, range 52–95 years). Marginally significant differences were observed in the intervention group (n=57) in comparison to the control group (n=30), regarding improvements in PA (difference of mean changes =866.4 steps, p=0.055) after 3 months. However, their PA decreased to the baseline score value after 12 months (-866.0 steps, p=0.061). GESTALT-kompakt did not cause significant differences in cognitive functioning (-0.8620, p=0.074) and social activities (-0.2428, p=0.288) in comparison to the control intervention from T0 to T1. Sixteen (24.2%) study participants who finished T2 reported a negative life event during the follow-up period, which severely influenced their PA behavior. GESTALT-kompakt might be effective in increasing PA in the short term, but did not have a long-term impact on the PA levels, cognitive functions or social activities of the participants. We recommend PA programs with longer duration to change behavior in the long term

A randomized study to evaluate the effect of exercise on fatigue in people with relapsing–remitting multiple sclerosis treated with fingolimod

Background Fatigue is a major symptom of multiple sclerosis (MS) in patients, and it has been shown to improve with physical exercise. Although fingolimod might lessen fatigue, it is unclear how patients treated with fingolimod react to physical activity regarding fatigue. Objective This study evaluated the effect of an exercise intervention on fatigue in relapsing–remitting MS patients receiving fingolimod. Methods People with MS (PwMS) were randomized to either a structured internet-based exercise program (e-training) or no e-training intervention. The primary endpoint was the change in the Modified Fatigue Impact Scale (mFIS) after six months. Results The primary analysis showed no statistically significant difference between groups in the mFIS change. Subgroup analyses revealed a beneficial effect of physical exercise for PwMS with low aerobic capacity and with low aerobic capacity plus more severe fatigue. The incidence of adverse events was similar in both groups. No cardiovascular events were reported. The majority of PwMS were relapse free. Conclusion Physical exercise benefits on fatigue may depend on the physical capacity of the patient and requires individualized training. Consistent with previous studies, these results suggest that physical exercise generally does not impose a risk and that this holds true also for patients receiving fingolimod

Internet-based exercise and physical activity promotion for persons with multiple sclerosis: a randomized controlled trial

Background We evaluated the effects of a 12-week internet-based exercise and physical activity promotion program for persons with multiple sclerosis. Methods We performed a multicenter, randomized, waitlist-controlled study. The intervention group (IG) received the 12-week program, followed by 12 weeks with usual care. The control group (CG) received usual care only. The main components of the 12-week program were: (1) a tailored home-based exercise prescription, (2) e-learning resources, (3) telephone and video meetings with an exercise therapist, (4) the provision of a consumer-based PA monitor. Measurements were taken at baseline, postintervention, and after 24 weeks. The primary outcome was device-measured steps/day. Other outcomes were device-measured moderate-to-vigorous physical activity, subjectively measured leisure-time and transportation physical activity and sport/exercise, physical activity-related health competence, walking ability, quality of life, fatigue, depression, and PA-related self-concordance. We compared changes from baseline to postintervention between groups and analyzed changes in the IG during the follow-up. Results Analysis of 56 persons with multiple sclerosis (IG: n  = 29, CG: n  = 27, age: 45.6 ± 10.9) revealed no significant intervention effect on steps/day. However, significant improvements were observed in moderate-to-vigorous physical activity, sport/exercise, control competence, fatigue, and quality of life (physical). During the follow-up, sport/exercise and quality of life decreased significantly. Leisure-time and transportation physical activity increased significantly. Conclusions Our study provides first evidence that the developed program can increase control competence, aspects of physical activity and health in persons with multiple sclerosis. A trial with a larger sample is recommended to confirm our results and examine intervention mechanisms. Trial registration Registry: Clinicaltrials.gov; registration number: NCT04367389; date of registration: 2020-04-21 (retrospectively registered).Open Access funding enabled and organized by Projekt DEAL.Friedrich-Alexander-Universität Erlangen-Nürnberg (1041