Multi scale shape index for 3D object recognition

We present Multi Scale Shape Index (MSSI), a novel feature for 3D object recognition. Inspired by the scale space filtering theory and Shape Index measure proposed by Koenderink & Van Doorn [6], this feature associates different forms of shape, such as umbilics, saddle regions, parabolic regions to a real valued index. This association is useful for representing an object based on its constituent shape forms. We derive closed form scale space equations which computes a characteristic scale at each 3D point in a point cloud without an explicit mesh structure. This characteristic scale is then used to estimate the Shape Index. We quantitatively evaluate the robustness and repeatability of the MSSI feature for varying object scales and changing point cloud density. We also quantify the performance of MSSI for object category recognition on a publicly available dataset. © 2013 Springer-Verlag.

Multi-scale permeability of murine bone measured by nanoindentation

The determination of lacunar-canalicular permeability is essential to understand the mechano-transduction mechanism of bone. Murine models are widely used to investigate skeletal growth and regulation, but the value of lacunar-canalicular permeability is still unclear. To address this question, a poroelastic analysis based on nanoindentation data was used to calculate the lacunar-canalicular permeability of wild type C57BL/6 mice of 12 months. Cross-sections of three tibiae were indented using spherical fluid cell indenter tips of two sizes. Results suggest that the value of lacunar-canalicular intrinsic permeability of B6 female murine tibia is in the order of 10 -24 m2. The distribution of the values of intrinsic permeability suggests that with larger contact sizes, nanoindentation alone is capable of capturing the multi-scale permeability of bone. Multi-scale permeability of bone measured by nanoindentation will lead to a better understanding of the role of fluid flow in mechano-transduction. © 2013 American Society of Civil Engineers.

Computational engineering design for micro-scale combustion devices: A thermally improved configuration

A multi-objective design optimisation study has been carried out with the objectives to improve the overall efficiency of the device and to reduce the fuel consumption for the proposed micro-scale combustor design configuration. In a previous study we identified the topology of the combustion chamber that produced improved behaviour of the device in terms of the above design criteria. We now extend our design approach, and we propose a new configuration by the addition of a micro-cooling channel that will improve the thermal behaviour of the design as previously suggested in literature. Our initial numerical results revealed an improvement of 2.6% in the combustion efficiency when we applied the micro-cooling channel to an optimum design configuration we identified from our earlier multi-objective optimisation study, and under the same operating conditions. The computational modelling of the combustion process is implemented in the commercial computational fluid dynamics package ANSYS-CFX using Finite Rate Chemistry and a single step hydrogen-air reaction. With this model we try to balance good accuracy of the combustion solution and at the same time practicality within the context of an optimisation process. The whole design system comprises also the ANSYS-ICEM CFD package for the automatic geometry and mesh generation and the Multi-Objective Tabu Search algorithm for the design space exploration. We model the design problem with 5 geometrical parameters and 3 operational parameters subject to 5 design constraints that secure practicality and feasibility of the new optimum design configurations. The final results demonstrate the reliability and efficiency of the developed computational design system and most importantly we assess the practicality and manufacturability of the revealed optimum design configurations of micro-combustor devices. Copyright © 2013 by ASME.

Investigation of magnetic wedge effects in large-scale BDFMs

This paper studies the effects of magnetic wedges on the equivalent circuit parameters of the Brushless Doubly-Fed Machine (BDFM). Magnetic wedges are used in slot openings of large electrical machines to reduce magnetizing currents, but the study of their effects on the BDFM performance is not straightforward due to the complex magnetic fields in the BDFM. Equivalent circuit and FE models have been developed for a 250 kW BDFM taking into account the effects of wedges and verified experimentally.

Gynogenesis and sex determination in large-scale loach Paramisgurnus dabryanus (Sauvage)

Gynogenesis was induced using heterologous sperms in large-scale loach, Paramisgurnus dabryanus (Sauvage), in which a ZW/ZZ sex determination was previously proposed. Three microsatellite loci were used to monitor exclusive maternal inheritance of gynogenetic progenies. The results showed that high percentages of meiogynogens were produced at 4 min post-fertilization and mitogynogens were produced at 18 min post-fertilization by heat shocks, while meiotic gynogenesis was induced by cold shocks within a wide period and high heterozygosity was even observed in gynogens produced at 24 min post-fertilization. The sex ratios of the F, progenies in three gynogenetic families were significantly deviated from 1: 1 expectation with a female bias in two families and a male bias in one family (P < 0.05), and the other four gynogenetic families showed approximate 1:1 sex ratios. Moreover, the self-mating between gynogenetic F, progenies and mating between gynogenetic F, progenies and normal individuals produced all-female progenies or identical proportions of females and males. The data of sex ratios generally confirmed that the sex determination in large-scale loach was determined by the putative ZW/ZZ system, and the possible reasons causing the biased sex ratios are discussed.

Studies on the restoration succession of PFU microbial communities in a pilot-scale microcosm

In order to imitate the restoration succession process of natural water ecosystem, a laboratory microcosm system of constant-flow-restoration was designed and established. A eutrophycation lake, Lake Donghu, was selected as the subject investigated. Six sampling stations were set on the lake, among which the water of station IV was natural clean water, and others were polluted with different degrees. Polyurethane foam unit microbial communities, which had colonized in the stations for a month, were collected from these stations and placed in their respective microcosms, using clean water of station IV to gradually replace the water of these microcosms. In this process, the healthy community in clean water continuously replaced the damaged communities in polluted water, the restoration succession of the damaged communities was characterized by weekly determination of several functional and structural community parameters, including species number (S), diversity index (DI), community pollution value (CPV), heterotrophy index (HI), and similarity coefficient. Cluster analysis based on similarity coefficient was used to compare the succession discrepancies of these microbial communities from different stations. The ecological succession of microbial communities during restoration was investigated by the variable patterns of these parameters, and based on which, the restoration standards of these polluted stations were suggested in an ecological sense. That was, while being restored, the water of station 0 (supereutrophycation) should be substituted with natural clean water by 95%; station I (eutrophycation), more than 90%; station II (eutrophycation), more than 85%; station III (eutrophycation), about 85%; station V (mesoetitrophycation), less than 50%. The effects of the structural and functional parameters in monitoring and assessing ecological restoration are analyzed and compared. (C) 2007 Elsevier Ltd. All rights reserved.

Realization of submicron-scale square-like silicon waveguide via optimized LOCOS process

We demonstrate the design, fabrication and experimental characterization of submicron-scale silicon waveguide fabricated by local oxidation of silicon and provide guidelines for controlling its profile. Near field measurements shows submicron confinement of the optical mode. © 2010 Optical Society of America.

Top down scale-up of semiconducting nanostructures for large area electronics

In this paper, we present a study on electrical and optical characteristics of n-type tin-oxide nanowires integrated based on top-down scale-up strategy. Through a combination of contact printing and plasma based back-channel passivation, we have achieved stable electrical characteristics with standard deviation in mobility and threshold voltage of 9.1% and 25%, respectively, for a large area of 1× 1 cm2 area. Through use of contact printing, high alignment of nanowires was achieved thus minimizing the number of nanowire-nanowire junctions, which serve to limit carrier transport in the channel. In addition, persistent photoconductivity has been observed, which we attribute to oxygen vacancy ionization and subsequent elimination using a gate pulse driving scheme. © 2014 IEEE.

STUDIES ON MIXED MASS CULTIVATION OF ANABAENA SPP (NITROGEN-FIXING BLUE-GREEN-ALGAE, CYANOBACTERIA) ON A LARGE-SCALE

Studies on mixed mass cultivation of Anabaena spp. on a large scale (5170 m2) were conducted continuously for 3 years. Under the continental monsoon climate in northern subtropics (30-degrees-N, 115-degrees-E), 7-11 g dry weight m-2 day-1 of microalgal biomass on average was harvested in simple plastic greenhouses in the effective growth days during the warmer seasons. The maximum productivity was 22 g m-2 day-1 in the middle of summer. Observations on the productive properties of strains of Anabaena spp. indicated that they were different from and could compensate for each other in their productivities and adaptations to the seasonal changes. With different lining materials (PVC sheets, concrete, sand and soil) in the culture ponds, no significant variation of productivity was found, but bubbling with biogas in the middle of the day and the application of some growth regulating substances (2,4-D, NaHSO3 and extracts of oyster mushroom spawn) was able to improve the production. The cost of microalgal biomass in this way was around 0.75-1.0 US dollar(s) per kilogram.

Large-scale synthesis of single-phase, high-quality GaN nanocrystallites

Large-scale synthesis of high-quality GaN nano-crystallites has been achieved by direct reaction of a 4:1 molar Ga/Ga2O3 mixture with ammonia at 950degreesC. X-ray diffraction, transmission electron microscopy, selected-area electron diffraction and high-resolution transmission electron microscopy revealed that the produced GaN nanocrystallites were single hexagonal wurtzite structure with an average particle size around 45 nm. A sharp near band edge emission peak and a blue light emission peak were observed in photoluminescence spectroscopy. The synthesis approach is simple and easy to be commercialized.

Novel folding large-scale optical switch matrix with total internal reflection mirrors on silicon-on-insulator by anisotropy chemical etching

A compact optical switch matrix was designed, in which light circuits were folded by total internal reflective (TIR) mirrors. Two key elements, 2 x 2 switch and TIR mirror, have been fabricated on silicon-on-insulator wafer by anisotropy chemical etching. The 2 x 2 switch showed very low power consumption of 140 mW and a very high speed of 8 +/- 1 mus. An improved design for the TIR mirror was developed, and the fabricated mirror with smooth and vertical reflective facet showed low excess loss of 0.7 +/- 0.3 dB at 1.55 mum.

Temperature dependence of the formation of nano-scale indium clusters in InAlGaN alloys on Si(111) substrates

The temperature dependence of the formation of nano-scale indium clusters in InAlGaN quaternary alloys, which are grown by metalorganic chemical vapour deposition on GaN/Si(111) epilayers, is investigated. Firm evidence is provided to support the existence of phase separation, or nano-scale In-rich clusters, by the combined results of high-resolution transmission electron microscopy (HRTEM), high-resolution x-ray diffraction (HRXRD) and micro-Raman spectra. The results of HRXRD and Raman spectra indicate that the degree of phase separation is strong and the number of In clusters in the InAlGaN layers on silicon substrate is higher at lower growth temperatures than that at higher growth temperatures, which limits the In and Al incorporated into the InAlGaN quaternary alloys. The detailed mechanism of luminescence in this system is studied by low temperature photoluminescence (LT-PL). We conclude that the ultraviolet (UV) emission observed in the quaternary InAlGaN alloys arises from the matrix of a random alloy, and the second emission peak in the blue-green region results from the nano-scale indium clusters.

Blue-violet photoluminescence from large-scale highly aligned boron carbonitride nanofibers

We report on the strong blue-violet photoluminescence (PL) at room temperature from the large-scale highly aligned boron carbonitride (BCN) nanofibers synthesized by bias-assisted hot filament chemical vapor deposition. The photoluminescence peak wavelength shifts in the range of 470-390 nm by changing the chemical composition of the BCN nanofibers, which shows an interesting blue and violet-light-emitting material with adjustable optical properties. The mechanism for the shift of the PL peaks at room temperature is also discussed. (C) 2000 American Institute of Physics. [S0003-6951(00)04427-2].