Die Erziehung zum Mute durch Turnen, Spiel und Sport: Die geistige Seite der Leibesübungen

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Allemagne. Une prise de conscience tardive

En matière d’évaluation, l’Allemagne a une tradition beaucoup plus limitée que celle de la France et d’autres pays comparables. Mais ces dernières années, la question de l’évaluation des établissements scolaires a vu, en Allemagne aussi, son importance grandir considérablement, pour deux raisons notamment. On voit maintenant, plus tard que dans d’autres pays, se multiplier les débats sur une plus grande autonomie de l’école. L’accès des établissements scolaires à l’autonomie va de pair avec l..

Evaluation of common supermarket products as positive controls in biochemical methane potential (BMP) tests

Biochemical methane potential (BMP) tests are commonly applied to evaluate the recoverable amount of methane from a substrate. Standardized protocols require inclusion of a positive control with a known BMP to check the experimental setup and execution, as well as the performance of the inoculum. Only if the BMP of the positive control is within the expected range is the entire test validated. Besides ignorance of this requirement, limited availability of the standard positive control microcrystalline cellulose might be the main reason for neglecting a positive control. To address this limitation, eight widely available grocery store products have been tested as alternative positive controls (APC) to demonstrate their suitability. Among them, Tic Tacs and gummi bears were very promising, although they are dominated by easily degradable sugars and so do not test for hydrolytic performance. Coffee filters exhibited a similar performance to microcrystalline cellulose, while whole milk might be chosen when a more balanced carbohydrate:protein:lipid ratio is important. Overall, the approach of predicting the BMP of a substrate based on the nutritional composition provided on the product packaging worked surprisingly well: BMP of the eight tested products was 81-91% of theoretical maximum BMP based on nutritional information and generic chemical formulas for carbohydrates, proteins, and lipids

Matematički pristup za unapređenje pouzdanosti podešavanja parametara u modeliranju procesa anaerobne digestije

The Nash-Sutcliffe model efficiency coefficient (ENSC) has been modified in order to assess the quality of simulations compared to observed data from the mesophilic monofermentation of grass silage. By applying the ENSC it is not only possible to find parameter sets with the best fit, but also to analyze the sensitivity of each parameter. For modeling the concentration of hydrogen, both the maximum uptake rate for hydrogen km_H2 and half-saturation coefficient of hydrogen KS_H2 are equally sensitive. Modeling the concentration of organic acids as acetate, propionate and butyrate, maximum uptake rate km as well as the free ammonia inhibition constant for acetate uptake KI_NH3 and hydrogen inhibition constants KI_H2, respectively are much more sensitive than their corresponding half-saturation constants KS. Only changes of hydrogen inhibition constants and maximum uptake of acetate compared to the ADM1 suggested values (for mesophilic sludge digestion) were necessary to fit the measurements.Model Nash-Sutcliffe koeficijenta efikasnosti (ENSC) primijenjen je u svrhu procjene kvalitete simulacija u usporedbi s promatranim podacima mezofilne monofermentacije travne silaže. Primjenom ENSC nije moguće pronaći najbolje moguće odgovarajuće skupove parametara, isto tako nije moguće analizirati osjetljivost svakog parametra. Za modeliranje koncentracije vodika, jednako su osjetljivi maksimalna stopa unosa vodika km_H2 kao i poluzasićenost vodikom KS_H2. Modeliranje koncentracije organskih kiselina kao acetata, propionata i butirata, maksimalni unos km jednako kao i konstanta inhibicije bez amonijaka za unos acetata KI_NH3 i konstanta inhibicije vodika KI_H2, mnogo više su osjetljiviji u odnosu na njihove odgovarajuće poluzasićene konstante KS. Za odgovarajuća mjerenja samo su bile potrebne promjene konstante inhibicije vodika i maksimalnog unosa acetate u usporedbi s ADMI predloženim vrijednostima (za mezofilnu digestiju taloga)

Exploring the potential of co-fermenting sewage sludge and lipids in a resource recovery scenario

In this study, co-fermentation of primary sludge (PS) or waste activated sludge (WAS) with lipids was explored to improve volatile fatty acid production. PS and WAS were used as base substrate to facilitate lipid fermentation at 20 °C under semi-aerobic conditions. Mono-fermentation tests showed higher VFA yields for PS (32-89 mgCOD gVS-1) than for WAS (20-41 mgCOD gVS-1) where propionate production was favoured. The principal component analysis showed that the base substrate had a notable influence on co-fermentation yields and profile. Co-fermentation with WAS resulted in a greater extent of oleic acid degradation (up to 4.7%) and evidence of chain elongation producing valerate. The occurrence of chain elongation suggests that co-fermentation can be engineered to favour medium-chain fatty acids without the addition of external commodity chemicals. BMP tests showed that neither mono-fermentation nor co-fermentation had an impact on downstream anaerobic digestion

Power and limitations of biochemical methane potential (BMP) tests

As energy systems transition toward renewable sources, anaerobic digestion (AD), which can be used to recover energy from organic substrates, is receiving growing attention. AD research and practice both rely on biochemical methane potential (BMP) tests to determine the methane potential of sewage sludge, energy crops and organic wastes (Pearse et al., 2018). In contrast to continuous reactor experiments, BMP tests are batch, and can be conducted without a major investment of equipment, labor and time. However, this and other differences limit the applicability of results from a BMP test to full-scale plant operation. Yet even in the peer-reviewed literature, BMP test results are not always used appropriately. An example is the determination of synergistic or antagonistic effects during anaerobic co-digestion in substrate mixtures. A BMP test is a powerful and useful tool, but it is important to recognize the type of questions that can and cannot be answered with this experimental setup. Clarification of these issues is the objective of the present contribution

From exam to education: the math exam/educational resources

peer-reviewedThe Math Exam/Education Resources (MER) is an open online learning resource hosted at The University of British Columbia (UBC), aimed at providing mathematics education resources for students and instructors at UBC. In this paper, there will be a discussion of the motivation for creating this resource on the MediaWiki platform, key features of the implementation that support student learning (including the evolution of the MER wiki from an exam database to more general learning resource), data on student use and response, potential for future development, and a brief description of how the project was implemented. Preliminary correlation data between wiki usage and exam performance are shared along with some preliminary data from an ongoing impact study.peer-reviewe