From Ideal to Practice and Back Again: Beginning Teachers Teaching for Social Justice

The five authors of this article designed a multicase study to follow recent graduates of an elementary preservice teacher education program into their beginning teaching placements and explore the ways in which they enacted social justice curricula. The authors highlight the stories of three beginning teachers, honoring the plurality of their conceptions of social justice teaching and the resiliency they exhibited in translating social justice ideals into viable pedagogy. They also discuss the struggles the teachers faced when enacting social justice curricula and the tenuous connection they perceived between their conceptions and their practices. The authors emphasize that such struggles are inevitable and end the article with recommendations for ways in which teacher educators can prepare beginning teachers for the uncertain journey of teaching for social justice

Considerations on minimum friction velocity

The concept of the minimum friction velocity is studied using three different methods of scalar averaging for the calculation of the stresses. Particular emphasis is given to the extraction of the influence of a non-zero ambient wind shear observed in field measurements. Data from three different experimental sites in Athens with high roughness values are analysed in order to provide information concerning the dependence of the dimensionaless minimum friction velocity on the dimensionless roughness length. Data from the BOREX-95 experiment have also been re-analysed according to the methodologies presented in this study. The results are compared to the large-eddy simulations that are considered to be a reference study on shear-free convection

Polyphenol Release from Wheat Bran Using Ethanol-Based Organosolv Treatment and Acid/Alkaline Catalysis: Process Modeling Based on Severity and Response Surface Optimization

Wheat bran (WB) is globally a major food industry waste, with a high prospect as a bioresource in the production of precious polyphenolic phytochemicals. In this framework, the current investigation had as objectives (i) to use ethanol organosolv treatment and study the effect of acid and alkali catalysts on releasing bound polyphenols, (ii) establish linear and quadratic models of polyphenol recovery based on severity and response surface, and (iii) examine the polyphenolic composition of the extracts generated. Using sulfuric acid and sodium hydroxide as the acid and the alkali catalyst, respectively, it was found that the correlation of combined severity factor with total polyphenol yield was significant in the acid catalysis, but a highly significant correlation in the alkali-catalyzed process was established with modified severity factor, which takes into consideration catalyst concentration, instead of pH. Optimization of the process with response surface confirmed that polyphenol release from WB was linked to treatment time, but also catalyst concentration. Under optimized conditions, the acid- and alkali-catalyzed processes afforded total polyphenol yields of 10.93 ± 0.62 and 19.76 ± 0.76 mg ferulic acid equivalents g−1 dry mass, respectively. Examination of the polyphenolic composition revealed that the alkali-catalyzed process had a striking effect on releasing ferulic acid, but the acid catalysis was insufficient in this regard. The outcome concerning the antioxidant properties was contradictory with respect to the antiradical activity and ferric-reducing power of the extracts, a fact most probably attributed to extract constituents other than ferulic acid. The process modeling proposed herein may be valuable in assessing both process effectiveness and severity, with a perspective of establishing WB treatments that would provide maximum polyphenol recovery with minimum harshness and cost. © 2022 by the authors

Surface fluxes under shear-free convenction

In this study, theoretical models of Schumann, Sykes et al., Beljaars, and Zilitinkevich et al. are examined, compared with data, and evaluated with regard to the calculation of the minimum friction velocity and the heat transfer coefficient. All data employed in earlier papers, namely those from meteorological campaigns SCOPE, TOGA COARE and BOREX-95, and the Schmidt and Schumann and Sykes and Henn large-eddy simulations (LESs), are considered. To achieve objective comparison between different formulae, empirical coefficients are recalculated by fitting theoretical curves separately for field data and for data from LESs. Despite essential differences in the shapes of the vertical profiles and the surface-layer height formulations applied in different models, practically all of them perform rather similarly and in fairly good correspondence with the chosen data set. However, a remarkable systematic difference is observed between data from measurements, on the one hand, and LES data, on the other. It is argued that this difference results from a contribution from uncounted mean-wind shear to the friction velocity in the field experiments. By this expedient, applicability of LESs to the resistance and heat-mass transfer problem is confirmed, and empirical coefficients in the resistance and heat transfer formulations are refined

The role of renewable energy sources within the framework of the Kyoto Protocol: the case of Greece

The exploitation of Renewable Energy Sources (RES) forms an integral part of the effort to reduce the negative impacts from the use of fossil fuels and to confront the risks associated with climate change. The Kyoto Protocol (KP) sets legally binding commitments for developed countries with respect to their greenhouse gases emissions and, in that, represents the first step of a systematic effort for stabilization of greenhouse gases concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Taking into account that CO2, originating almost exclusively from energy processes, is the most important greenhouse gas, the further development of RES forms an essential measure for the reduction of emissions. This paper examines whether the current development and planned actions in the field of the RES, even when straightforwardly associated with very ambitious targets for the present decade (e.g., the draft European Directive on the promotion of electricity from renewable energy sources in the internal electricity market), are sufficient in order to achieve the commitments according to the KP or more effort is needed in the direction of RES exploitation, combined with complementary actions such as energy conservation.