Flow induced vibration of a square cylinder with high scruton number

Flow over a square cylinder is numerically studied to understand the effect of reduced velocity to the transverse oscillation under the influence of high Scruton number elastic system of 4.316. For low reduced velocities, the transverse oscillation behavior can be grouped in the initial branch region. In this region, the motion is mainly controlled by the lift fluctuation. For intermediate reduced velocities, the transverse oscillation behavior is grouped in the lower branch region. In this region, its natural frequency slowly becomes significant. For high reduced velocities, the galloping region is observed. In this region, the natural frequency dominated the shape of the amplitude oscillation

Aerodynamics characteristics around simplified high speed train model under the effect of crosswinds

The aerodynamics problems of train commonly come when the flow pass through train body. The increasing speed of train to achieve highly technology demands has led to increase the forces and moments and increase sensitivity of train stability and may cause the train to overturn. In this paper, two prisms arranged in tandem represent a simplified model of high speed train are performed at different yaw angle ranging from 0° to 90° by using the unsteady Reynolds- Averaged Navier Stokes (URANS) equation combined with k-ω SST turbulence model. The Reynolds number is 3.14x105based on height of the train and the free stream velocity. The aerodynamic quantities such as the side force, lift force and drag force coefficient show a similar trend where the forces increase with the yaw angle until a certain critical yaw angle before start to decrease till the yaw angle of 90°. The flow structure around the train under the effect of crosswind is visualized. The vorticiticy start to form from the nose and slowly drifts away further towards the trailing edge. The two-dimensional mean streamlines on the cross-section of train at different yaw angle show that the size of vortex increase as the yaw angle increase. Time averaged pressure contour plotted on the cross section along x-axis show the variation of region between high pressure and low pressure region on the leeward and windward side of the train model that may cause train to overturn. © 2006-2017 Asian Research Publishing Network (ARPN)

Aerodynamics characteristics around simplified high speed train model under the effect of crosswinds

The aerodynamics problems of train commonly come when the flow pass through train body. The increasing speed of train to achieve highly technology demands has led to increase the forces and moments and increase sensitivity of train stability and may cause the train to overturn. In this paper, two prisms arranged in tandem represent a simplified model of high speed train are performed at different yaw angle ranging from 0° to 90° by using the unsteady Reynolds- Averaged Navier Stokes (URANS) equation combined with k-ω SST turbulence model. The Reynolds number is 3.14x105based on height of the train and the free stream velocity. The aerodynamic quantities such as the side force, lift force and drag force coefficient show a similar trend where the forces increase with the yaw angle until a certain critical yaw angle before start to decrease till the yaw angle of 90°. The flow structure around the train under the effect of crosswind is visualized. The vorticiticy start to form from the nose and slowly drifts away further towards the trailing edge. The two-dimensional mean streamlines on the cross-section of train at different yaw angle show that the size of vortex increase as the yaw angle increase. Time averaged pressure contour plotted on the cross section along x-axis show the variation of region between high pressure and low pressure region on the leeward and windward side of the train model that may cause train to overturn. © 2006-2017 Asian Research Publishing Network (ARPN)

Comparative study on energy extraction from vibrating square cylinder

In this paper, the prospect of harvesting energy from flow induced-vibration of a square cylinder is assessed. The extraction of energy from the flow is attained by mounting the square cylinder on a one-degree elastic system with a massdamping (m*ζ) of 2.75. OpenFOAM®, an open source CFD package is used to model the flow induced motion of the square cylinder. A theoretical formulation to estimate the lift force acting on the square cylinder is derived to confirm the results obtained by the simulation. A good agreement between the results is obtained. The amplitude vibration and lift force are then used to estimate the power induced by the oscillating square cylinder. Energy in the micro scale range can be harvested from this flow induced-vibration system. This type of alternative green energy is suitable for the micro energy harvester system required for sensors in many engineering structure for health monitoring purpose

Colocalization of 14-3-3 Proteins with SOD1 in Lewy Body-Like Hyaline Inclusions in Familial Amyotrophic Lateral Sclerosis Cases and the Animal Model

Background and Purpose: Cu/Zn superoxide dismutase (SOD1) is a major component of Lewy body-like hyaline inclusion (LBHI) found in the postmortem tissue of SOD1-linked familial amyotrophic lateral sclerosis (FALS) patients. In our recent studies, 14-3-3 proteins have been found in the ubiquitinated inclusions inside the anterior horn cells of spinal cords with sporadic amyotrophic lateral sclerosis (ALS). To further investigate the role of 14-3-3 proteins in ALS, we performed immunohistochemical analysis of 14-3-3 proteins and compared their distributions with those of SOD1 in FALS patients and SOD1-overexpressing mice. Methods: We examined the postmortem brains and the spinal cords of three FALS cases (A4V SOD1 mutant). Transgenic mice expressing the G93A mutant human SOD1 (mutant SOD1-Tg mice), transgenic mice expressing the wild-type human SOD1 (wild-type SOD1-Tg mice), and non-Tg wild-type mice were also subjected to the immunohistochemical analysis. Results: In all the FALS patients, LBHIs were observed in the cytoplasm of the anterior horn cells, and these inclusions were immunopositive intensely for pan 14-3-3, 14-3-3$\beta$, and 14-3-3$\gamma$. In the mutant SOD1-Tg mice, a high degree of immunoreactivity for misfolded SOD1 (C4F6) was observed in the cytoplasm, with an even greater degree of immunoreactivity present in the cytoplasmic aggregates of the anterior horn cells in the lumbar spinal cord. Furthermore, we have found increased 14-3-3$\beta$ and 14-3-3$\gamma$ immunoreactivities in the mutant SOD1-Tg mice. Double immunofluorescent staining showed that C4F6 and 14-3-3 proteins were partially co-localized in the spinal cord with FALS and the mutant SOD1-Tg mice. In comparison, the wild-type SOD1-Tg and non-Tg wild-type mice showed no or faint immunoreactivity for C4F6 and 14-3-3 proteins (pan 14-3-3, 14-3-3$\beta$, and 14-3-3$\gamma$) in any neuronal compartments. Discussion: These results suggest that 14-3-3 proteins may be associated with the formation of SOD1-containing inclusions, in FALS patients and the mutant SOD1-Tg mice.Mathematic

Scanned Probe Oxidation onp-GaAs(100) Surface with an Atomic Force Microscopy

Locally anodic oxidation has been performed to fabricate the nanoscale oxide structures onp-GaAs(100) surface, by using an atomic force microscopy (AFM) with the conventional and carbon nanotube (CNT)-attached probes. The results can be utilized to fabricate the oxide nanodots under ambient conditions in noncontact mode. To investigate the conversion of GaAs to oxides, micro-Auger analysis was employed to analyze the chemical compositions. The growth kinetics and the associated mechanism of the oxide nanodots were studied under DC voltages. With the CNT-attached probe the initial growth rate of oxide nanodots is in the order of ~300 nm/s, which is ~15 times larger than that obtained by using the conventional one. The oxide nanodots cease to grow practically as the electric field strength is reduced to the threshold value of ~2 × 107 V cm−1. In addition, results indicate that the height of oxide nanodots is significantly enhanced with an AC voltage for both types of probes. The influence of the AC voltages on controlling the dynamics of the AFM-induced nanooxidation is discussed

The marine myxosporean Sigmomyxa sphaerica (Thélohan, 1895) gen. n., comb. n. (syn. Myxidium sphaericum) from garfish (Belone belone (L.)) uses the polychaete Nereis pelagica L. as invertebrate host

Sigmomyxa sphaerica (Thélohan, 1892) gen. n. (Myxozoa, Myxosporea) with myxosporean stages in the gall bladder of Belone belone (L.) (Teleostei, Belonidae) uses the polychaete Nereis pelagica L. (Nereidae) from shallow water in the northern Øresund, Denmark, as invertebrate host. The nearly spherical tetractinomyxon-type actinospores of S. sphaerica differ from those of two species of Ellipsomyxa which also use Nereis spp. as invertebrate host. Pansporocysts of S. sphaerica were not seen. S. sphaerica is redescribed on the basis of myxospore stages from B. belone and actinospores from N. pelagica, and the phylogenetic affinities examined on the basis of ribosomal small subunit gene sequences. S. sphaerica is closest related to Ellipsomyxa spp., and is not congeneric with morphologically similar Myxidium spp. from gadids. This is the fifth elucidated two-host life cycle of a marine myxozoan

A53T-alpha-synuclein-overexpression in the mouse nigrostriatal pathway leads to early increase of 14-3-3 epsilon and late increase of GFAP

Parkinson’s disease (PD) is a neurodegenerative disorder frequent at old age characterized by atrophy of the nigrostriatal projection. Overexpression and A53T-mutation of the presynaptic, vesicle-associated chaperone alpha-synuclein are known to cause early-onset autosomal dominant PD. We previously generated mice with transgenic overexpression of human A53T-alpha-synuclein (A53T-SNCA) in dopaminergic substantia nigra neurons as a model of early PD. To elucidate the early and late effects of A53T-alpha-synuclein on the proteome of dopaminergic nerve terminals in the striatum, we now investigated expression profiles of young and old mice using two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE) and mass spectrometry. In total, 15 proteins were upregulated and 2 downregulated. Mice before the onset of motor anomalies showed an upregulation of the spot containing 14-3-3 proteins, in particular the epsilon isoform, as well as altered levels of chaperones, vesicle trafficking and bioenergetics proteins. In old mice, the persistent upregulation of 14-3-3 proteins was aggravated by an increase of glial fibrillary acidic protein (GFAP) suggesting astrogliosis due to initial neurodegeneration. Independent immunoblots corroborated GFAP upregulation and 14-3-3 upregulation for the epsilon isoform, and also detected significant eta and gamma changes. Only for 14-3-3 epsilon a corresponding mRNA increase was observed in midbrain, suggesting it is transcribed in dopaminergic perikarya and accumulates as protein in presynapses, together with A53T-SNCA. 14-3-3 proteins associate with alpha-synuclein in vitro and in pathognomonic Lewy bodies of PD brains. They act as chaperones in signaling, dopamine synthesis and stress response. Thus, their early dysregulation probably reflects a response to alpha-synuclein toxicity