5,101 research outputs found
Embedded shear layers in turbulent boundary layers of a NACA0012 airfoil at high angles of attack
An investigation of turbulent boundary layers (TBLs) is presented for a
NACA0012 airfoil at angles of attack 9 and 12 deg. Wall-resolved large eddy
simulations (LES) are conducted for a freestream Mach number M = 0.2 and
chord-based Reynolds number Re = 4x10^5, where the boundary layers are tripped
near the airfoil leading edge on the suction side. For the angles of attack
analyzed, mild, moderate and strong adverse pressure gradients (APGs) develop
over the airfoil. Despite the strong APGs, the mean flow remains attached along
the entire airfoil suction side. Similarly to other APG-TBLs investigated in
the literature, a secondary peak appears in the Reynolds stress and turbulence
production profiles. This secondary peak arises in the outer layer and, for
strong APGs, it may overcome the first peak typically observed in the inner
layer. The analysis of the turbulence production shows that other components of
the production tensor become important in the outer layer besides the shear
term. For moderate and strong APGs, the mean velocity profiles depict three
inflexion points, the third being unstable under inviscid stability criteria.
In this context, an embedded shear layer develops along the outer region of the
TBL leading to the formation of two-dimensional rollers typical of a
Kelvin-Helmholtz instability which are captured by a spectral proper orthogonal
decomposition (SPOD) analysis. The most energetic SPOD spatial modes of the
tangential velocity show that streaks form along the airfoil suction side and,
as the APG becomes stronger, they grow along the spanwise and wall-normal
directions, having a spatial support along the entire boundary layer
Stabilizer Quantum Error Correction with Qubus Computation
In this paper we investigate stabilizer quantum error correction codes using
controlled phase rotations of strong coherent probe states. We explicitly
describe two methods to measure the Pauli operators which generate the
stabilizer group of a quantum code. First, we show how to measure a Pauli
operator acting on physical qubits using a single coherent state with large
average photon number, displacement operations, and photon detection. Second,
we show how to measure the stabilizer operators fault-tolerantly by the
deterministic preparation of coherent cat states along with one-bit
teleportations between a qubit-like encoding of coherent states and physical
qubits.Comment: 4 pages, 5 figure
A trans10-18:1 enriched fraction from beef fed a barley grain-based diet induces lipogenic gene expression and reduces viability of HepG2 cells.
Beef fat is a natural source of trans (t) fatty acids, and is typically enriched with either t10-18:1 or t11-18:1. Little is known about the bioactivity of individual t-18:1 isomers, and the present study compared the effects of t9-18:1, cis (c)9-18:1 and trans (t)-18:1 fractions isolated from beef fat enriched with either t10-18:1 (HT10) or t11-18:1 (HT11). All 18:1 isomers resulted in reduced human liver (HepG2) cell viability relative to control. Both c9-18:1 and HT11were the least toxic, t9-18:1had dose response increased toxicity, and HT10 had the greatest toxicity (P<0.05). Incorporation of t18:1 isomers was 1.8-2.5 fold greater in triacylglycerol (TG) than phospholipids (PL), whereas Δ9 desaturation products were selectively incorporated into PL. Culturing HepG2 cells with t9-18:1 and HT10 increased (P<0.05) the Δ9 desaturation index (c9-16:1/16:0) compared to other fatty acid treatments. HT10 and t9-18:1 also increased expression of lipogenic genes (FAS, SCD1, HMGCR and SREBP2) compared to control (P<0.05), whereas c9-18:1 and HT11 did not affect the expression of these genes. Our results suggest effects of HT11 and c9-18:1 were similar to BSA control, whereas HT10 and t-9 18:1 (i.e. the predominant trans fatty acid isomer found in partially hydrogenated vegetable oils) were more cytotoxic and led to greater expression of lipogenic genes
File Specification for the 7-km GEOS-5 Nature Run, Ganymed Release Non-Hydrostatic 7-km Global Mesoscale Simulation
This document describes the gridded output files produced by a two-year global, non-hydrostatic mesoscale simulation for the period 2005-2006 produced with the non-hydrostatic version of GEOS-5 Atmospheric Global Climate Model (AGCM). In addition to standard meteorological parameters (wind, temperature, moisture, surface pressure), this simulation includes 15 aerosol tracers (dust, sea-salt, sulfate, black and organic carbon), O3, CO and CO2. This model simulation is driven by prescribed sea-surface temperature and sea-ice, daily volcanic and biomass burning emissions, as well as high-resolution inventories of anthropogenic sources. A description of the GEOS-5 model configuration used for this simulation can be found in Putman et al. (2014). The simulation is performed at a horizontal resolution of 7 km using a cubed-sphere horizontal grid with 72 vertical levels, extending up to to 0.01 hPa (approximately 80 km). For user convenience, all data products are generated on two logically rectangular longitude-latitude grids: a full-resolution 0.0625 deg grid that approximately matches the native cubed-sphere resolution, and another 0.5 deg reduced-resolution grid. The majority of the full-resolution data products are instantaneous with some fields being time-averaged. The reduced-resolution datasets are mostly time-averaged, with some fields being instantaneous. Hourly data intervals are used for the reduced-resolution datasets, while 30-minute intervals are used for the full-resolution products. All full-resolution output is on the model's native 72-layer hybrid sigma-pressure vertical grid, while the reduced-resolution output is given on native vertical levels and on 48 pressure surfaces extending up to 0.02 hPa. Section 4 presents additional details on horizontal and vertical grids. Information of the model surface representation can be found in Appendix B. The GEOS-5 product is organized into file collections that are described in detail in Appendix C. Additional details about variables listed in this file specification can be found in a separate document, the GEOS-5 File Specification Variable Definition Glossary. Documentation about the current access methods for products described in this document can be found on the GEOS-5 Nature Run portal: http://gmao.gsfc.nasa.gov/projects/G5NR. Information on the scientific quality of this simulation will appear in a forthcoming NASA Technical Report Series on Global Modeling and Data Assimilation to be available from http://gmao.gsfc.nasa.gov/pubs/tm/
Exploring Randomly Wired Neural Networks for Climate Model Emulation
Exploring the climate impacts of various anthropogenic emissions scenarios is
key to making informed decisions for climate change mitigation and adaptation.
State-of-the-art Earth system models can provide detailed insight into these
impacts, but have a large associated computational cost on a per-scenario
basis. This large computational burden has driven recent interest in developing
cheap machine learning models for the task of climate model emulation. In this
manuscript, we explore the efficacy of randomly wired neural networks for this
task. We describe how they can be constructed and compare them to their
standard feedforward counterparts using the ClimateBench dataset. Specifically,
we replace the serially connected dense layers in multilayer perceptrons,
convolutional neural networks, and convolutional long short-term memory
networks with randomly wired dense layers and assess the impact on model
performance for models with 1 million and 10 million parameters. We find
average performance improvements of 4.2% across model complexities and
prediction tasks, with substantial performance improvements of up to 16.4% in
some cases. Furthermore, we find no significant difference in prediction speed
between networks with standard feedforward dense layers and those with randomly
wired layers. These findings indicate that randomly wired neural networks may
be suitable direct replacements for traditional dense layers in many standard
models
Theology, Mission and Child: Global Perspectives
In our view there are three primary and equally constituent parts to the volume we have been commissioned to edit and collate, and these are therefore indicated in the title.https://scholar.csl.edu/edinburghcentenary/1023/thumbnail.jp
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