8,452 research outputs found
Manufacturing requirements
In recent years, natural laminar flow (NLF) has been proven to be achievable on modern smooth airframe surfaces over a range of cruise flight conditions representative of most current business and commuter aircraft. Published waviness and boundary layer transition measurements on several modern metal and composite airframes have demonstrated the fact that achievable surface waviness is readily compatible with laminar flow requirements. Currently, the principal challenge to the manufacture of NLF-compatible surfaces is two-dimensional roughness in the form of steps and gaps at structural joints. Results of recent NASA investigations on manufacturing tolerances for NLF surfaces, including results of a flight experiment are given. Based on recent research, recommendations are given for conservative manufacturing tolerances for waviness and shaped steps
Gene Loss and Horizontal Gene Transfer Contributed to the Genome Evolution of the Extreme Acidophile âFerrovumâ
IndexaciĂłn: Web of Science. Scopus.Acid mine drainage (AMD), associated with active and abandoned mining sites, is a habitat for acidophilic microorganisms that gain energy from the oxidation of reduced sulfur compounds and ferrous iron and that thrive at pH below 4. Members of the recently proposed genus "Ferrovurn" are the first acidophilic iron oxidizers to be described within the Betaproteobacteria. Although they have been detected as typical community members in AMD habitats worldwide, knowledge of their phylogenetic and metabolic diversity is scarce. Genomics approaches appear to be most promising in addressing this lacuna since isolation and cultivation of "Ferrovurn" has proven to be extremely difficult and has so far only been successful for the designated type strain-Ferrovum myxofaciens" P3G. In this study, the genomes of two novel strains of "Ferrovurn" (PN-J185 and Z-31) derived from water samples of a mine water treatment plant were sequenced. These genomes were compared with those of "Ferrovum" sp. JA12 that also originated from the mine water treatment plant, and of the type strain (P3G). Phylogenomic scrutiny suggests that the four strains represent three "Ferrovum" species that cluster in two groups (1 and 2). Comprehensive analysis of their predicted metabolic pathways revealed that these groups harbor characteristic metabolic profiles, notably with respect to motility, chemotaxis, nitrogen metabolism, biofilm formation and their potential strategies to cope with the acidic environment. For example, while the "F myxofaciens" strains (group 1) appear to be motile and diazotrophic, the non-motile group 2 strains have the predicted potential to use a greater variety of fixed nitrogen sources. Furthermore, analysis of their genome synteny provides first insights into their genome evolution, suggesting that horizontal gene transfer and genome reduction in the group 2 strains by loss of genes encoding complete metabolic pathways or physiological features contributed to the observed diversification.http://journal.frontiersin.org/article/10.3389/fmicb.2016.00797/ful
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Languages and Learning at Key Stage 2: A Longitudinal Study Final Report
In 2006, The Open University, the University of Southampton and Canterbury Christ Church University were commissioned by the then Department for Education and Skills (DfES), now Department for Children, Schools and Families (DCSF) to conduct a three-year longitudinal study of languages learning at Key Stage 2 (KS2). The qualitative study was designed to explore provision, practice and developments over three school years between 2006/07 and 2008/09 in a sample of primary schools and explore childrenâs achievement in oracy and literacy, as well as the possible broader cross-curricular impact of languages learning
Understanding longitudinal bi-ventricular structural and functional changes in a Pulmonary Hypertension Sugen-Hypoxia rat model by Cardiac Magnetic Resonance Imaging
Feminist Experiences of âStudying upâ: Encounters with International Institutions
Feminist Experiences of \u27Studying up\u27: Encounters with International Institutions This article makes the case for feminist IR to build knowledge of international institutions. It emerges from a roundtable titled âChallenges and Opportunities for Feminist IR: Researching Gendered Institutionsâ which took place at the International Studies Association Annual Convention in Baltimore in 2017. Here, we engage in self-reflexivity, drawing upon our conversation to consider what it means for feminist scholars to âstudy upâ. We argue that feminist IR conceptions of narratives and the everyday make a valuable contribution to feminist institutionalist understandings of the formal and informal. We also draw attention to the value of postcolonial approaches, and multi-site analysis of international institutions for creating a counter-narrative to hegemonic accounts emerging from both the institutions themselves, and scholars studying them without a critical feminist perspective. In so doing, we draw attention to the salience of considering not just what we study as feminist International Relations scholars but how we study it. Spanish Experiencias feministas de \uabEstudiar a los de arriba\ubb: encuentros con instituciones internacionales Este art\uedculo plantea el argumento de que las relaciones internacionales (RR. II.) feministas pueden fomentar el conocimiento de las instituciones internacionales. Se destila de una mesa redonda denominada Challenges and Opportunities for Feminist IR: Researching Gendered Institutions(Retos y oportunidades para las RR. II. feministas: el estudio de las instituciones marcadas por el g\ue9nero) que tuvo lugar en la convenci\uf3n anual de la Asociaci\uf3n de Estudios Internacionales celebrada en Baltimore en 2017. Aqu\ued, nos sumergimos en la autorreflexi\uf3n, recurriendo a nuestra conversaci\uf3n para dilucidar qu\ue9 significa para los acad\ue9micos feministas \uabestudiar a los de arriba\ubb. Argumentamos que las concepciones feministas de las RR. II. sobre los relatos y lo cotidiano realizan una valiosa contribuci\uf3n a las interpretaciones institucionalistas feministas de lo formal y lo informal. Tambi\ue9n queremos destacar el valor de los enfoques poscoloniales y el an\ue1lisis de m\ufaltiples ubicaciones de las instituciones internacionales para crear un contrarrelato frente a los discursos hegem\uf3nicos que se derivan tanto de las propias instituciones como de los acad\ue9micos que las estudian sin una perspectiva feminista cr\uedtica. Al hacerlo, pretendemos destacar la trascendencia de tener en cuenta no solo lo que estudiamos como acad\ue9micos feministas de Relaciones Internacionales, sino tambi\ue9n c\uf3mo lo estudiamos.Palabras clave: g\ue9nero, instituciones internacionales, relaciones internacionales feministas French Exp\ue9riences f\ue9ministes de \uab studying up \ubb : \uc0 la rencontre des institutions internationalesCet article affirme la n\ue9cessit\ue9 pour lâapproche f\ue9ministe des RI de renforcer le savoir en mati\ue8re dâinstitutions internationales. Il est issu dâune table ronde intitul\ue9e \uab D\ue9fis et opportunit\ue9s pour lâapproche f\ue9ministes des RI : Recherche sur les institutions genr\ue9es \ubb ayant eu lieu \ue0 Baltimore en 2017 lors de la convention annuelle de lâInternational Studies Association. Nous entreprenons ici un travail de r\ue9flexion sur nous-m\ueames \ue0 partir de notre discussion sur la question de savoir ce que \uab study up \ubb signifie pour les chercheurs f\ue9ministes. Nous soutenons que les conceptions f\ue9ministes des r\ue9cits et du quotidien dans les RI contribuent positivement \ue0 une compr\ue9hension f\ue9ministe institutionnaliste du formel et de lâinformel. Nous mettons \ue9galement en exergue la valeur des approches postcoloniales et de lâanalyse sur plusieurs sites des institutions internationales dans la cr\ue9ation dâun r\ue9cit alternatif aux r\ue9cits h\ue9g\ue9moniques provenant \ue0 la fois des institutions elles-m\ueames et des chercheurs qui les \ue9tudient sans cadre dâanalyse critique f\ue9ministe. Nous attirons ainsi lâattention sur lâimportance pour nous, en tant que sp\ue9cialistes des relations internationales sous un angle f\ue9ministe, de bien r\ue9fl\ue9chir non seulement \ue0 lâobjet de nos recherches, mais \ue9galement \ue0 la mani\ue8re dont nous effectuons ces recherches.Mots-cl\ue9s : genre, institutions internationales, relations internationales f\ue9ministes
Electrochemical regeneration of a graphite adsorbent loaded with Acid Violet 17 in a spouted bed reactor
A novel spouted bed reactor is evaluated for water treatment by an adsorption and electrochemical regeneration process. The adsorbent is a bisulphate graphite intercalation compound with low specific surface area but high electrical conductivity, suitable for adsorption of contaminants and simultaneous electrochemical regeneration within a single unit. The effects of current density and liquid flow rate on Acid Violet 17 removal were investigated. The hydrodynamic behavior of the liquid spouted bed reactor was characterized by a flow regime map. A four-parameter model has been developed to describe the adsorption and electrochemical regeneration process in the liquid spouted bed reactor. It was found that the experimental data of dye removal agrees well with the modelled simulations
The role of spatial frequency information for ERP components sensitive to faces and emotional facial expression
To investigate the impact of spatial frequency on emotional facial expression analysis, ERPs were recorded in response to low spatial frequency (LSF), high spatial frequency (HSF), and unfiltered broad spatial frequency (BSF) faces with fearful or neutral expressions, houses, and chairs. In line with previous findings, BSF fearful facial expressions elicited a greater frontal positivity than BSF neutral facial expressions, starting at about 150 ms after stimulus onset. In contrast, this emotional expression effect was absent for HSF and LSF faces. Given that some brain regions involved in emotion processing, such as amygdala and connected structures, are selectively tuned to LSF visual inputs, these data suggest that ERP effects of emotional facial expression do not directly reflect activity in these regions. It is argued that higher order neocortical brain systems are involved in the generation of emotion-specific waveform modulations. The face-sensitive N170 component was neither affected by emotional facial expression nor by spatial frequency information
Aeolianite and barrier dune construction spanning the last two glacial-interglacial cycles from the southern Cape coast, South Africa
The southern Cape region of South Africa has extensive coastal aeolianites and barrier dunes. Whilst previously reported, limited knowledge of their age has precluded an understanding of their relationship with the climatic and sea-level fluctuations that have taken place during the Late Quaternary. Sedimentological and geomorphological studies combined with an optical dating programme reveal aeolianite development and barrier dune construction spanning at least the last two glacialâinterglacial cycles. Aeolianite deposition has occurred on the southern Cape coast at ca 67â80, 88â90, 104â128, 160â189 and >200 ka before the present. Using this and other published data coupled with a better understanding of Late Quaternary sea-level fluctuations and palaeocoastline configurations, it is concluded that these depositional phases appear to be controlled by interglacial and subsequent interstadial sea-level high stands. These marine transgressions and regressions allowed onshore carbonate-rich sediment movement and subsequent aeolian reworking to occur at similar points in the landscape on a number of occasions. The lack of carbonates in more recent dunes (Oxygen Isotope Stages 1/2 and 4/5) is attributed not to leaching but to changes to carbonate production in the sediment source area caused by increased terrigenous material and/or changes in the balance between the warm Agulhas and nutrient-rich Benguela ocean current
Incoherent non-Fermi liquid scattering in a Kondo lattice
One of the most notorious non-Fermi liquid properties of both archetypal
heavy-fermion systems [1-4] and the high-Tc copper oxide superconductors [5] is
an electrical resistivity that evolves linearly with temperature, T. In the
heavy-fermion superconductor CeCoIn5 [5], this linear behaviour was one of the
first indications of the presence of a zero-temperature instability, or quantum
critical point. Here, we report the observation of a unique control parameter
of T-linear scattering in CeCoIn5, found through systematic chemical
substitutions of both magnetic and non-magnetic rare-earth, R, ions into the Ce
sub-lattice. We find that the evolution of inelastic scattering in Ce1-xRxCoIn5
is strongly dependent on the f-electron configuration of the R ion, whereas two
other key properties -- Cooper-pair breaking and Kondo-lattice coherence -- are
not. Thus, T-linear resistivity in CeCoIn5 is intimately related to the nature
of incoherent scattering centers in the Kondo lattice, which provides insight
into the anomalous scattering rate synonymous with quantum criticality [7].Comment: 4 pages, 3 figures (published version
Model Order Reduction for Rotating Electrical Machines
The simulation of electric rotating machines is both computationally
expensive and memory intensive. To overcome these costs, model order reduction
techniques can be applied. The focus of this contribution is especially on
machines that contain non-symmetric components. These are usually introduced
during the mass production process and are modeled by small perturbations in
the geometry (e.g., eccentricity) or the material parameters. While model order
reduction for symmetric machines is clear and does not need special treatment,
the non-symmetric setting adds additional challenges. An adaptive strategy
based on proper orthogonal decomposition is developed to overcome these
difficulties. Equipped with an a posteriori error estimator the obtained
solution is certified. Numerical examples are presented to demonstrate the
effectiveness of the proposed method
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