936 resultados para Paramorphogenic form


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Despite their high abundance and their high importance for the oceanic matter flux, heterotrophic nanoflagellates are only poorly studied in the deep-sea regions. Studies on the choanoflagellate distribution during two deep-sea expeditions, to the South Atlantic (5038 m) and Antarctica (Weddell Sea, 2551 m), revealed the deepest records of choanoflagellates so far. A new species, (Lagenoeca antarctica) with a conspicuous spike structure on the theca is described from deep Antarctic waters. Lagenoeca antarctica sp. n. is a solitary unstalked free living salpingoecid-like choanoflagellate. The protoplast is surrounded by a typical theca with unique spikes only visible in SEM micrographs. The ovoid cell nearly fills the whole theca and ranges in size from 4 to 6 µm. The collar measures 2-3 µm and the flagellum 3-5 µm. A second species, Salpingoeca abyssalis sp. n., was isolated from the abyssal plain of the South Atlantic (5038 m depth). Floating and attached forms were observed. The protoplast ranges from to 2 to 4 µm in length and 1 to 2 µm in width. The collar is about the same length as the protoplast and the flagellum has 2 to 2.5 × the length of the protoplast. Phylogenetic analyses based on a fragment of SSU rDNA revealed Salpingoeca abyssalis to cluster together with a marine isolate of Salpingoeca infusionum while Lagenoeca antarctica clusters separately from the other codonosigid and salpingoecid taxa. Salpingoeca abyssalis and an undetermined Monosiga species seems to be the first choanoflagellate species recorded from the abyssal plain.

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Using data from a self-administered survey of 1,017 households we assess the long-term impact of establishing a special economic zone, on those who are exogenously selected to be displaced. We find those who are displaced suffer from lower land compensation and lack of adequate property rights. There is also some evidence of lower labour market participation among those who are displaced. However, in the long term, across measurable welfare indicators, we do not find that displaced households are significantly different from other households. One source of this resilience is through employment at the special economic zone – which is higher among displaced households compared to other households. Another factor that contributed to the absence of differences is spill-over effects; which made access to employment, education and other facilities about homogenous across displaced and non-displaced households.

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Derive coordinate-free expressions for geometric characteristics of conics written in Bézier form in terms of their control points and weights.

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El artículo examina un nuevo sistema envolvente ligero, delgado, con ahorro energético, libre de formas diseñado para su uso en proyectos de arquitectura.

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Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. These restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern when dealing with optical design. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. The general designing procedure will be described in detail

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Development of a novel HCPV nonimaging concentrator with high concentration (>500x) and built-in spectrum splitting concept is presented. It uses the combination of a commercial concentration GaInP/GaInAs/Ge 3J cell and a concentration Back-Point-Contact (BPC) silicon cell for efficient spectral utilization, and external confinement techniques for recovering the 3J cell's reflection. The primary optical element (POE) is a flat Fresnel lens and the secondary optical element (SOE) is a free-form RXI-type concentrator with a band-pass filter embedded in it - Both the POE and SOE performing Köhler integration to produce light homogenization on the receiver. The band-pass filter transmits the IR photons in the 900-1200 nm band to the silicon cell. A design target of an "equivalent" cell efficiency ~46% is predicted using commercial 39% 3J and 26% Si cells. A projected CPV module efficiency of greater than 38% is achievable at a concentration level larger than 500X with a wide acceptance angle of ±1°. A first proof-of concept receiver prototype has been manufactured using a simpler optical architecture (with a lower concentration, ~100x and lower simulated added efficiency), and experimental measurements have shown up to 39.8% 4J receiver efficiency using a 3J cell with a peak efficiency of 36.9%.

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This article examines, from the energy viewpoint, a new lightweight, slim, high energy efficient, light-transmitting envelope system, providing for seamless, free-form designs for use in architectural projects. The research was based on envelope components already existing on the market, especially components implemented with granular silica gel insulation, as this is the most effective translucent thermal insulation there is today. The tests run on these materials revealed that there is not one that has all the features required of the new envelope model, although some do have properties that could be exploited to generate this envelope, namely, the vacuum chamber of vacuum insulated panels (VIP), the monolithic aerogel used as insulation in some prototypes, reinforced polyester barriers. By combining these three design components — the high-performance thermal insulation of the vacuum chamber combined with monolithic silica gel insulation, the free-form design potential provided by materials like reinforced polyester and epoxy resins—, we have been able to define and test a new, variable geometry, energy-saving envelope system.

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The influence of the main cereal and feed form of the diet on performance and digestive tract traits was studied in 576 brown-egg laying pullets from 1 to 120 d of age. From 1 to 45 d of age, 4 diets arranged factorially with 2 cereals (corn vs. wheat) and 2 feed forms (mash vs. pellets) were used. Each treatment was replicated 6 times (24 pullets per replicate). From 46 to 120 d of age, all diets were offered in mash form and the only difference among diets was the cereal used. Cumulatively, pullets fed the corn diets had higher BW gain (P < 0.05) but similar feed conversion ratio as pullets fed the wheat diets. From 1 to 45 d of age, pullets fed pellets consumed more feed (P < 0.001) and had higher BW gain (P < 0.001) than those fed mash. Most of the beneficial effects of pelleting on productive performance were still evident at 120 d of age. At 45 d of age, gizzard weight (g/kg of BW) was higher (P < 0.01) in pullets fed corn than in pullets fed wheat diets. Feeding pellets reduced the relative weight of the digestive tract and the gizzard (P < 0.001) as well as the length (cm/kg of BW) of the small intestine (P < 0.01) at both ages. The pH of gizzard contents at 120 d of age was not affected by cereal but was lower in pullets that were fed mash from 1 to 45 d of age (P < 0.01). We conclude that wheat can be used in substitution of corn in pullet diets with only a slight reduction in BW gain and that feeding pellets from 1 to 45 d of age increased BW gain and pH of the gizzard and reduced the relative weight of the gizzard and the length of the gastrointestinal tract at 120 d of age.

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In this work, a new two-dimensional optics design method is proposed that enables the coupling of three ray sets with two lens surfaces. The method is especially important for optical systems designed for wide field of view and with clearly separated optical surfaces. Fermat’s principle is used to deduce a set of functional differential equations fully describing the entire optical system. The presented general analytic solution makes it possible to calculate the lens profiles. Ray tracing results for calculated 15th order Taylor polynomials describing the lens profiles demonstrate excellent imaging performance and the versatility of this new analytic design method.

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The two-dimensional analytic optics design method presented in a previous paper [Opt. Express 20, 5576–5585 (2012)] is extended in this work to the three-dimensional case, enabling the coupling of three ray sets with two free-form lens surfaces. Fermat’s principle is used to deduce additional sets of functional differential equations which make it possible to calculate the lens surfaces. Ray tracing simulations demonstrate the excellent imaging performance of the resulting free-form lenses described by more than 100 coefficients.