QCGAT aircraft/engine design for reduced noise and emissions

The high bypass ratio QCGAT engine played an important role in shaping the aircraft design. The aircraft which evolved is a sleek, advanced design, six-place aircraft with 3538 kg (7,800 lb) maximum gross weight. It offers a 2778 kilometer (1500 nautical mile) range with cruise speed of 0.5 Mach number and will take-off and land on the vast majority of general aviation airfields. Advanced features include broad application of composite materials and a supercritical wing design with winglets. Full-span fowler flaps were introduced to improve landing capability. Engines are fuselage-mounted with inlets over the wing to provide shielding of fan noise by the wing surfaces. The design objectives, noise, and emission considerations, engine cycle and engine description are discussed as well as specific design features

Some hypersonic intake studies

A 'two dimensional' air intake comprisipg a wedge followed by an isentropic compression has been tested in the Cranfield Gun Tunnel at Mach 8,2. These tests were performed to investigate qualitatively the intake flow starting process. The effects of cowl position, Reynolds number, boundary-layer trip and introduction of a small restriction in the intake duct were investigated. Schlieren pictures of the flow on the compression surface and around the intake entrance were taken. Results showed that the intake would operate over the Reynolds number range tested. Tests with a laminar boundary layer demonstrated the principal influence of the Reynolds number on the boundary-layer growth and consequently on the flow structure in the intake entrance. In contrast boundary layer tripping produced little variation in flow pattern over the Reynolds number range tested. The cowl lip position appeared to have a strong effect on the intake performance. The only parameter which prevented the intake from starting was the introduction of a restriction in the intake duct. The experimental data obtained were in good qualitative agreement with the CFD predictions. Finally, these experimental results indicated a good intake flow starting process over multiple changes of parameters

Crystal structure of Ni-sorbed synthetic vernadite: A powder X-ray diffraction study

International audienceVernadite is a nanocrystalline turbostratic phyllomanganate ubiquitous in the environment, which contains nickel in specific settings such as oceanic sediments. To improve our understanding of nickel uptake in this mineral, two series of synthetic analogs to vernadite (δ-MnO2) were prepared with Ni/Mn atomic ratios ranging from 0.002 to 0.105 at pH 4 and from 0.002 to 0.177 at pH 7, and their structures characterised using X-ray diffraction (XRD). The δ-MnO2 nano-crystals are essentially monolayers with coherent scattering domain sizes of ~10 Å perpendicular to the layer and of ~55 Å in the layer plane. The layers contain an effective proportion of ~18% vacant octahedral sites, regardless of the Ni content. At Ni/Mn ratios <1%, XRD has no sensitivity to Ni, and the layer charge deficit is apparently entirely balanced by interlayer Mn, Na, and protons. At higher Ni/Mn ratios, Ni occupies the same site as interlayer Mn above and/or below layer vacancies together with sites along the borders of the MnO2 layers, but the layer charge is balanced differently at the two pH values. At pH 4, Ni uptake is accompanied by a decrease in structural Na and protons, whereas interlayer Mn remains strongly bound to the layers. At pH 7, interlayer Mn is less strongly bound and partly replaced by Ni. The results also suggest that the number of vacant layer sites and multivalent charge-compensating interlayer species are underestimated in the current structure models for δ-MnO2

Crystal structure of mixed-layer minerals and their X-ray identification: New insights from X-ray diffraction profile modeling.

Modeling of experimental X-ray diffraction (XRD) patterns represents the optimum approach to the structure determination of mixed-layer structures (MLSs) that are commonly found in natural clay-rich samples. This approach allows for a detailed structural characterization of both pure and mixed-layer clay phases and for a semi-quantitative phase analysis in complex mixtures. The two informations are essential to gain new insight into the actual nature of reactions taking place in geological environments. Significant new findings obtained at different scales (from that of the particle to that of the elementary layer) on the actual structure of MLSs by modeling XRD profiles are reported

Elements for a rereading of the geographical concept of territory in Di Meo in the light of the actual convergent dynamics of ICT

La dinámica de las TICs, en el vertiginoso contexto convergente actual, señala la necesidad de su incorporación al análisis territorial en pos de comprender su participación y sus efectos sobre este y sobre la sociedad. En este sentido, el presente trabajo se propone presentar elementos para una relectura de la propuesta metodológica desarrollada por Guy Di Meo (la Formación Socio Espacial), a fin de posibilitar la incorporación de estas tecnologías a dicha herramienta. La elección de esta herramienta resulta de su concepción relacional, multidimensional, multiescalar y sistémica del territorio, perspectiva que a nuestro entender la hace apta para el análisis pretendido en el marco de los avances del campo geográfico actual.The dynamics of ICTs in the fast converging current context identified the need for incorporate the territorial analysis towards understanding their participation and their effects on this and on society. In this sense, this paper aims to present elements for a rereading of the methodology developed by Guy Di Meo (Socio Spatial Formation) in order to facilitate the integration of these technologies that tool.The choice of this tool is its relational, multidimensional, multiscale and systematic conception of territory perspecti ve that we believe makes it suitable for analysis intended as part of the progress of the current geographic al area.Fil: Lanson, Daniel Ernesto. Universidad Nacional de Lujá

Cryptomelane formation from nanocristalline vernadite precursor.

International audienceVernadite is a nanocristalline and turbostratic phyllomanganate which is ubiquitous in the environment. Its layers, built of MnO6 octahedra connected through their edges, contain vacancies and (or) isomorphic substitutions, both creating a layer charge deficit that can exceed 1 valence unit per layer octahedron. In addition, vernadite has a high affinity for many trace metals (e.g., Co, Ni and Zn) and frequently contain heterovalent Mn cations which provides this mineral with the capacity to oxidize redox-sensitive trace elements (e.g., As, Se) and organic pollutants. As a result of these exceptional properties, vernadite controls the fate of many trace elements in soils and sediments. In the environment, vernadite is often found associated with tectomanganates (“tunnel”-like structures) such as cryptomelane, of which it is thought to be the precursor. A sound description of the vernadite-to-cryptomelane transformation, at the atomic scale, is mandatory to be able to understand and thus model the fate of metals initially present in vernadite structure. To contribute to a better understanding of this transformation, we have synthesized vernadite samples having various Mn4+/Mn3+ ratios (and thus various layer charge) and we have monitored their transformation, under conditions analogous to those prevailing in soils (dry state and ambient conditions, in the dark) over a time scale of ~10 years [1-2]. Initial samples were characterized using a combination of chemistry, thermogravimetric analyses and powder X-ray diffraction. Samples structural formula ranged between Na+0.06(H2O)0.30Mn3+0.19[Mn3+0.12Mn4+0.71Vac0.17O2] (where species under brackets form the layer – “Vac” stands for “layer vacancies”, and species on the left are in the interlayer space) and Na+0.27(H2O)0.30Mn3+0.10[Mn3+0.10Mn4+0.76Vac0.14O2]. Transformation was monitored using high-energy X-ray scattering (with both Bragg-rod and pair distribution function formalisms) and transmission electron microscopy (TEM and STEM). With time, layer Mn3+ was found to migrate in the interlayer, probably to reduce strains induced by its Jahn-Teller distorted coordination sphere. When the abundance of interlayer Mn3+ reached ~0.3 per layer octahedron, interlayer Mn3+ from adjacent layers were found to share their hydration sphere and to form cryptomelane domains

Zn sorption modifies dynamically the layer and interlayer structure of vernadite

International audienceIn surficial environments, the fate of many trace metals is influenced by their interactions with the phyllomanganate vernadite, a nano-sized and turbostratic variety of birnessite. To advance our understanding of the surface reactivity of vernadite, synthetic vernadite (δ-MnO2) was equilibrated at pH 5 or 7, reacted with dissolved Zn to produce Zn-sorbed δ-MnO2 with Zn/Mn atomic ratios from 0.003 to 0.156, and characterized structurally. The octahedral layers in the Zn-free vernadite contain on average ∼0.15 vacancies, ∼0.13-0.06 Mn3+ and ∼0.72-0.79 Mn4+. The layer charge deficit is compensated in the interlayer by Mn3+ bonded over Mn vacancy sites and Na+ located in the interlayer mid-plane. The average lateral dimension of coherent scattering domains (CSDs) deduced from X-ray diffraction (XRD) modeling is ∼5 nm, consistent with that observed by transmission electron microscopy for individual crystals, indicating that the amounts of edge sites can be estimated by XRD. The average vertical dimension of CSDs is ∼1 nm, equivalent to 1.5 layers and less than the observed 3-4 layers in the particles. Zinc sorption at pH 5 and 7 on pre-equilibrated vernadite induced crystal dissolution reducing the lateral CSD size ∼15-20%. Zinc K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy and XRD show that Zn occurs in the interlayer above vacancies as a triple-corner-sharing surface complex, which is fully tetrahedral at low Zn/Mn ratios and increasingly octahedral at higher ratios. As Zn/Mn increases, the site density of layer Mn3+ decreases from 0.13 ± 0.01 to 0.03 ± 0.01 at pH 5 and from 0.06 ± 0.01 to 0.01 ± 0.01 at pH 7, and that of layer vacancies correspondingly increases from ∼0.15 to 0.24 and 0.21 at pH 5 and 7, respectively. These changes likely occur because of the preference of Zn2+ for regular coordination structures owing to its completely filled third electron shell (3d10 configuration). Thus, sorption of Zn into the interlayer causes the departure of layer Mn3+, subsequent formation of new reactive layer vacancies, and an increase in surface area through a reduction in particle size, all of which dynamically enhance the sorbent reactivity. These results shed new light on the true complexity of the reactive vernadite surface, and pose greater challenges for surface-complexation modeling of its sorption isotherms

Significado do turismo de peregrinación para o desenvolvemento local. Caso das peregrinacións á Basílica Nacional da Nosa Señora da Pura e Limpa Concepción do Río Luján, provincia de Bos Aires, Arxentina

[Resumen] Entre las características culturales que contribuyeron a forjar el valor turístico de la actual ciudad de Luján de la Provincia de Buenos Aires, Argentina, descuella, en particular, la religiosa, factor que constituye un elemento clave de la concepción de cualquier estrategia de desarrollo local que se asuma. El significado de la virgen de Luján, Nuestra Señora de la Pura y Limpia Concepción del río Luján, su historia, prácticamente, hilvana el relato científicamente edificado acerca del asentamiento y de la sociedad, lujanenses, en una amalgama permanentemente renovada por el fenómeno singular, por la diversidad de sus expresiones, de las peregrinaciones a Virgen y a la Basílica Nacional Nuestra Señora de Luján.[Resumo] Entre as características culturais que contribuíron a forzar o valor turístico da actual cidade de Luján da provincia de Bos Aires, Arxentina, sobresae, en particular, a relixiosa, factor que constitúe un elemento clave da concepción de calquera estratexia de desenvolvemento local que se asuma. O significado da virxe de Luján, A Nosa Señora da Pura e Limpa concepción do río Luján, a súa historia, practicamente ganduxa o relato cientificamente edificado acerca do asentamento e da sociedade lujanenses, nunha amálgama permanentemente renovada polo fenómeno singular, pola diversidade das súas expresións, das peregrinacións á Virxe e á Basílica Nacional da Nosa Señora de Luján.[Abstract] This includes an analysis of the promotion of the Camino de Santiago over the last few decades, the context in which this was carried out, the parties involved in the process, the promotional strategies to attract tourists and travel agencies, sponsorship, and collaboration with the private sector, with the political institutions, with the media and with civil society. It also examines the communication activities carried out, the materials used with their identifying symbols (mascot, logotype, credentials), the changes of image under the Xacobeo brand, and the link between the communication carried out (image projected), the confirmed initial image and the a posteriori image perceived by visitors

Luján (provincia de Buenos Aires, Argentina): imagen y destino turístico. Contribución al análisis de una perspectiva el patrimonio territorial

XII Coloquio de Geografía del Turismo, Ocio y Recreación de la Asociación de Geógrafos Españoles. Colmenarejo (Madrid), del 17 al 19 de junio de 2010

Demographic and clinical characteristics of primary and secondary care patients with osteoarthritis of hip and knee are quite similar

Purpose: As is stated in many guidelines for patients with osteoarthritis, it is advised to treat patients conservatively before patients are referred to secondary care. Therefore, it can be expected that secondary care patietns with osteoarthritis differ from primary care patients. The purpose of the current study is to compare demographic and clinical characteristics of patients with osteoarthritis who are referred to primary care physiotherapists and patients who are referred to secondary care. Methods: In a cross-sectional study secondary analyses were performed on two cohorts of patients with knee or hip osteoarthritis: one primary care dataset (n=200) and one secondary care dataset (n=279). In both studies comparable measurements were performed at baseline in the same time period. Measurements included, among others, gender, age, location and duration of osteoarthritis, number of comorbidities, pain (VAS), physical function (WOMAC), muscle strength, range of motion, social support and quality of life. Results: Both groups were similar in most characteristics, with some exceptions. The primary care group consisted of less patients with both hip and knee osteoarthritis and of younger patients compared to the secondary care group. Furthermore, secondary care patients reported more pain (4.0 versus 4.8), less muscle strength and more falls in the last six months. Conclusions: There are differences between primary and secondary care populations of patients with osteoarthritis, but these differences are minimal. Looking at the results of this research, the question arises whether the health care of patients with osteoarthritis can be organised more efficient and less expensive. However, long-term prospective studies are needed to evaluate the cost effectiveness of both primary and secondary care of patients with osteoarthritis. (aut. ref.