Materials for solar hydrogen production with simultaneous mineralization of ethanol

The photo-catalytic production of hydrogen by means of irradiation of a suspension of semiconductor oxides presents attractive features over other methods with higher cost such as water electrolysis. In this work, photocatalytic hydrogen production from water is studied, using ethanol as sacrificial agent. New nanostructured multifunctionalised semiconductor materials based on titanium dioxide, with effective photo-catalytic properties under UV illumination were synthesized using sol-gel technology and characterised by X-Ray diffraction and scanning electron microscopy. Aqueous suspensions of the semiconductor powders were used and the effect of solution pH and temperature (20-70ºC) as well as the effect of concentration of ethanol on hydrogen production were studied, for fixed concentrations of the catalyst. Comparison is made with doped Degussa-P25 TiO2 titanium dioxide. The need to decrease the electron-hole recombination rate was accounted for by metal doping [1] with the ethanol molecule acting as a hole trap. An increase in the hydrogen production rate was found as a result of the percentage of metal on doped titania and optimisation of experimental conditions with rate values being superior to recently published literature data [2]. Particle size, reactive surface area, structure and crystallinity of the semiconductor were found to be determinant in the production of highly photoactive titanium dioxide. Research in progress includes development of catalyst that allows effective utilization of visible light and design of an experimental reacto

Critical slowing down at a bifurcation

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Modeling the relationship between psychophysical perception and electrically evoked compound action potential threshold in young cochlear implant recipients: clinical implications for implant fitting

Purpose: To develop and evaluate a fast, automated multi-criterial treatment planning approach for adaptive high-dose-rate (HDR) intracavitary + interstitial brachytherapy (BT) for locally advanced cervical cancer. Methods and materials: Twenty-two previously delivered single fraction MRI-based HDR treatment plans (SFclin) were used to guide training of our in-house system for multi-criterial autoplanning, aiming for an autoplan quality superior to the training plans, while respecting the clinically desired “pear-shaped” dose distribution. Next, the configured algorithm was used to automatically generate treatment plans for 63 other fractions (SFauto). The SFauto plans were compared to the corresponding SFclin plans in blind pairwise comparisons by an expert clinician. Then, the effect of adaptive autoplanning on total treatment (TT) plans (external beam + 3 BT fractions) was evaluated for 16 patients by simulating the clinically applied adaptive strategy to generate TTauto plans and compare them with the corresponding clinical treatments (TTclin). Results: In the blind comparisons, all SFauto plans were considered clinically acceptable. In 62/63 comparisons, SFauto plans were considered at least as good as, or better than the corresponding SFclin. The average optimization time for autoplanning was 20.5 ± 19.2 s (range 4.4–106.4 s) per plan. In 14 of 16 TTauto plans, the desired total dose of 90 Gy (EQD2) was obtained, compared to only 9 in the corresponding TTclin, while autoplanning also decreased bladder and rectum doses. Conclusions: Fast, fully-automated multi-criterial treatment planning for adaptive HDR-BT for locally advanced cervical cancer is feasible. Autoplans were superior to corresponding clinical plans.RST/Reactor Physics and Nuclear Material