STUDY OF IDENTIFICATION OF TWO-PHASE FLOW PARAMETERS BY PRESSURE FLUCTUATION ANALYSIS

This paper deals with identification of parameters of simple pool boiling in a vertical rectangular channel by analysis of pressure fluctuation. In this work is introduced a small experimental facility about 9 kW power, which was used for simulation of pool boiling phenomena and creation of steam-water volume. Several pressure fluctuations measurements and differential pressure fluctuations measurements at warious were carried out. Main changed parameters were power of heaters and hydraulics resistance of channel internals. Measured pressure data was statistically analysed and compared with goal to find dependencies between parameters of two-phase flow and statistical properties of pressure fluctuation. At the end of this paper are summarized final results and applicability of this method for parameters determination of two phase flow for pool boiling conditions at ambient pressure

Addressing climate change with behavioral science: a global intervention tournament in 63 countries

Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions’ effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior—several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people’s initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors

Enhancing Bioavailability of Nutraceutically Used Resveratrol and Other Stilbenoids

Stilbenoids are interesting natural compounds with pleiotropic in vitro and in vivo activity. Their well-documented biological properties include anti-inflammatory effects, anticancer effects, effects on longevity, and many others. Therefore, they are nowadays commonly found in foods and dietary supplements, and used as a part of treatment strategy in various types of diseases. Bioactivity of stilbenoids strongly depends on different types of factors such as dosage, food composition, and synergistic effects with other plant secondary metabolites such as polyphenols or vitamins. In this review, we summarize the existing in vitro, in vivo, and clinical data from published studies addressing the optimization of bioavailability of stilbenoids. Stilbenoids face low bioavailability due to their chemical structure. This can be improved by the use of novel drug delivery systems or enhancers, which are discussed in this review. Current in vitro and in vivo evidence suggests that both approaches are very promising and increase the absorption of the original substance by several times. However, data from more clinical trials are required

Reaktivita vnitřních a vnějších Bronstedových kyselých poloh v nanoporézních MFI: kinetická studie H/D výměny

The strength of Bronsted acid sites (BAS) affects the properties of 2D and hierarchical zeolites, but the relative contribution of internal and external BAS remains unknown. Accordingly, this study aims to assess the acidity of external and internal BAS in nanosponge-like MFI zeolites by comparatively analyzing hydrogen-deuterium exchange kinetics between zeolitic deuteroxyl groups and C2H6 molecules monitored by in-situ FTIR spectroscopy. For this purpose, (i) a sample pre-treatment procedure was specifically developed to deuterate only internal or only external acid sites using 2,6-di-tert-butylpyridine (DTBP) as a masking agent and (ii) DFT modeling of surface BAS was performed. Theoretical models of the thin MFI layer revealed that the external surface of MFI crystals contains three types of BAS: (i) BAS positioned in 5-membered rings, either shielded by silanol nests, rendering the site inaccessible for DTBP or yielding a very low adsorption energy for ethane, (ii) BAS pointing into the pores, due to the presence of aluminol, which hinders DTBP accessibility, or the BAS undergoes transformation to a three-coordinate aluminium site, and (iii) BAS accessible to both DTBP and ethane. The results from our kinetics measurements showed that H/D exchange at external BAS of nanosponge MFI zeolites is faster than at internal BAS (rate constants at 425 degrees C: 3.8 10(-3) vs. 2.4 10(-3) s(-1) for external and internal BAS, respectively), but this cannot be attributed to the effect of diffusion. Therefore, the differences in exchange kinetics between external and internal BAS are given by mutual interplay of subtle differences in the corresponding activation barriers (113 vs. 117 kJ/mol for external and internal BAS, respectively) and pre-exponential terms (1.09 10(6) vs. 1.45 10(6) s(-1) for external and internal BAS, respectively).Síla Bronstedových kyselých poloh ovlivňuje vlastnosti 2D a hierarchických zeolitů. Tato studie byla zaměřen na zhodnocení kyselosti vnitřních a vnějších BAS v nanoporézních MFI zeolitech pomocí komparativní analýzy H/D výměny mezi deuteroxylovou skupinou a C2H6 molekulami. Tato výměna byla monitorována pomocí in-situ FTIR spektroskopie. Výsledky byly porovnány s DFT výpočty modelujícími povrchové BAS