A dynamically optimized finite difference scheme for Large-Eddy Simulation

AbstractA low-dispersive dynamic finite difference scheme for Large-Eddy Simulation is developed. The dynamic scheme is constructed by combining Taylor series expansions on two different grid resolutions. The scheme is optimized dynamically through the real-time adaption of a dynamic coefficient according to the spectral content of the flow, such that the global dispersion error is minimal. In the case of DNS-resolution, the dynamic scheme reduces to the standard Taylor-based finite difference scheme with formal asymptotic order of accuracy. When going to LES-resolution, the dynamic scheme seamlessly adapts to a dispersion-relation preserving scheme. The scheme is tested for Large-Eddy Simulation of Burgers equation. Very good results are obtained

Some Empirical Criteria for Attributing Creativity to a Computer Program

Peer reviewedPostprin

Stepping Beyond Libraries: The Changing Orientation in Global GLAM-Wiki

Wikipedia and its community has seen an increasingly close relationship between library communities, with both communities sharing overlapping values and practices related to public access to knowledge, a desire for openness, defence of freedom of speech, representing marginalized communities, and broad shared interest in reliable factual information and citations. This is best in evidence from the IFLA’ Wikipedia and Libraries Opportunity Papers and the substantial growth and ubiquity of the #1lib1ref campaign. However, the relationships between cultural heritage organizations (known as GLAMs -- Galleries, Libraries, Archives and Museums) and the Wikimedia communities working on Wikipedia, Wikimedia Commons and other Wikimedia projects, began in its relationships to Museums and Archives: partnerships like that with the British Museum in 2010 led to a collective effort to encourage GLAM organizations to contribute to and participate in Wikimedia Communities. Though early partnerships in the GLAM-Wiki space focused on batch uploads of digital content to Wikimedia Commons, embedding Wikimedia-designated experts called Wikipedians in Residence, and editing activities, like editathons, which write expert advised content into Wikipedia, in the last 6 years, the landscape in which partnership with cultural heritage institutions has shifted radically. Two major trends have developed in the Wikimedia community: a shift towards facilitating linked open data with Wikidata and the expansion of GLAM-Wiki projects to support institutions that not only have large digital capacity and funding, but also institutions with limited resources, collections focused on marginalized knowledge, and collections in parts of the world with limited digital expertise. In this transition, Wikimedia communities have become change agents in bringing both linked open data and open digital practices to institutions around the world. In this paper, we will explore how GLAM-Wiki tactics, opportunities and collaboration are changing the GLAM use of Wikimedia projects from being viewed as just a platform for exposing collection to a broader public audience, into a growing part of the heritage professional toolkit

Using conceptual metaphor and functional grammar to explore how language used in physics affects student learning

This paper introduces a theory about the role of language in learning physics. The theory is developed in the context of physics students' and physicists' talking and writing about the subject of quantum mechanics. We found that physicists' language encodes different varieties of analogical models through the use of grammar and conceptual metaphor. We hypothesize that students categorize concepts into ontological categories based on the grammatical structure of physicists' language. We also hypothesize that students over-extend and misapply conceptual metaphors in physicists' speech and writing. Using our theory, we will show how, in some cases, we can explain student difficulties in quantum mechanics as difficulties with language.Comment: Accepted for publication in Phys. Rev. ST:PE

Antioxydant activity, oxidative stability properties of Colza oil, comparison of mechanical agitated and ultrasonic extraction on green tea catechins of Camellia sinensis L.

peer reviewedUltrasonic extraction “UE” used to optimize the extraction yield of phenolic compounds “PC” from green tea Camellia sinensis L., and compared with mechanical agitated extraction “MAE”. UE was applied at different times (15, 10 and 5min) and temperatures (25, 60 and 95°C) and MAE was performed at these experimental conditions (15 min, 95°C, 400 rpm). Results demonstrate that the maximum yield of epigallocatechin 3-gallate “EGCG” extracted by UE was significantly (P < 0.05) higher than that obteined using MAE (136 mg/g vs 100 mg/g, respectively). The optimum conditions for the polyphenol compounds “PC” recovery are obtained using UE during 15 min at 95°C (~134.66 mg/g). Four catechins from extracted PC were identified using high-performance liquid chromatography equipped with a diode array detector and liquid chromatography mass spectrometry “HPLC-DAD & LC-MS”: epigallocatechin “EGC”, epicatechin “EC”, epigallocatechingallate “EGCG”, and epicatechin-gallate “ECG”. EGCG is the major compound in polyphenol extracts representing 60 %. The antioxidant capacity of the obtained extracts was also studied. Diphényl-2-pycril-hydrazyl “DPPH” scavenging activity is higher for UE than MAE (~ 90 % vs ~85%). Moreover, the PC obtained by UE added to colza oil had a higher oxidative stability, determined by rancimat than those extracted by MAE method (~30.62 h vs ~21.26 h). Results indicate the suitability of UE method for production of PC as potent antioxidant for stabilization of vegetable oils such as colza oil

From Teamchef Arminius to Hermann Junior: glocalised discourse about a national foundation myth

If for much of the nineteenth and twentieth centuries, the ‘Battle of the Teutoburg Forest’, fought in 9 CE between Roman armies and Germanic tribes, was predominantly a reference point for nationalist and chauvinist discourses in Germany, the first decade of the twenty-first century has seen attempts to link public remembrance with local/regional identities on the one hand and international/intercultural contact on the other. In the run up to and during the ‘anniversary year’ of 2009, German media, sports institutions and various other official institutions articulating tourist, economic and political interests attempted to create a new ‘glocalised’ version of the public memory of the Teutoburg battle. Combining methods of Cognitive Linguistics and Critical Discourse Analysis, the paper analyses the narrative and argumentative topoi employed in this re-orientation of public memory, with a special emphasis on hybrid, post-national identity-construction. Das zweitausendjährige Gedenkjahr der „Schlacht im Teutoburger Wald“ im Jahr 2009 bot eine günstige Gelegenheit, die bis in die zweite Hälfte des 20. Jahrhunderts dominante Tradition nationalistisch–chauvinistischer Deutungen des Sieges von germanischen Stämmen über drei römische Legionen zu korrigieren und zu überwinden. Der Aufsatz analysiert mit Hilfe diskurslinguistischer Methoden die Anstrengungen regionaler Institutionen und Medien, die nationale Vereinnahmung des historischen Gedenkens kritisch zu thematisieren sowie neue, zum eine lokal situierte, zum andern international orientierte Identifikationsangebote anzubieten. Die Analyse zeigt, dass solche „de-nationalisierten“ Identifikationsangebote zwar teilweise auch früher verwendet wurden, aber heutzutage rekontextualisiert und auf innovative Weise in den Vordergrund gestellt werden

Re-Imagining Images of Organization: A Conversation With Gareth Morgan

In this article, we review the metaphors presented by Morgan in Images of Organization and highlight how they simultaneously act as “relatively static reflections” (i.e., they provide a history of organization theory) and “relatively dynamic projections” (i.e., stimulating the formulation of further organizational images). We also discuss the potential for new organizational metaphors and consider two specific metaphors (i.e., the “global brain” and “organization as media”). We also challenge the established punctuated metaphorical process (i.e., a transfer from a metaphorical source domain to an organizational target domain), propose a dynamic perspective of interchange (i.e., source domain to target domain to source domain and so on), and develop the notion of multidirectionality (i.e., two-way projections between target and source domains)

Using resource graphs to represent conceptual change

We introduce resource graphs, a representation of linked ideas used when reasoning about specific contexts in physics. Our model is consistent with previous descriptions of resources and coordination classes. It can represent mesoscopic scales that are neither knowledge-in-pieces or large-scale concepts. We use resource graphs to describe several forms of conceptual change: incremental, cascade, wholesale, and dual construction. For each, we give evidence from the physics education research literature to show examples of each form of conceptual change. Where possible, we compare our representation to models used by other researchers. Building on our representation, we introduce a new form of conceptual change, differentiation, and suggest several experimental studies that would help understand the differences between reform-based curricula.Comment: 27 pages, 14 figures, no tables. Submitted for publication to the Physical Review Special Topics Physics Education Research on March 8, 200