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Turbulence

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https://www.readbyqxmd.com/read/28106437/main-ion-intrinsic-toroidal-rotation-profile-driven-by-residual-stress-torque-from-ion-temperature-gradient-turbulence-in-the-diii-d-tokamak
#1
B A Grierson, W X Wang, S Ethier, G M Staebler, D J Battaglia, J A Boedo, J S deGrassie, W M Solomon
Intrinsic toroidal rotation of the deuterium main ions in the core of the DIII-D tokamak is observed to transition from flat to hollow, forming an off-axis peak, above a threshold level of direct electron heating. Nonlinear gyrokinetic simulations show that the residual stress associated with electrostatic ion temperature gradient turbulence possesses the correct radial location and stress structure to cause the observed hollow rotation profile. Residual stress momentum flux in the gyrokinetic simulations is balanced by turbulent momentum diffusion, with negligible contributions from turbulent pinch...
January 6, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28103551/ultrasound-flow-mapping-for-the-investigation-of-crystal-growth
#2
Norman Thieme, Paul Bonisch, Dagmar Meier, Richard Nauber, Lars Buttner, Kaspars Dadzis, Olf Patzold, Lamine Sylla, Jurgen Czarske
A high energy conversion and cost efficiency are keys for the transition to renewable energy sources, e.g. solar cells. The efficiency of multi-crystalline solar cells can be improved by enhancing the understanding of its crystallization process, especially the directional solidification. In this paper, a novel measurement system for the characterization of flow phenomena and solidification processes in low-temperature model experiments on the basis of ultrasound Doppler velocimetry is described. It captures turbulent flow phenomena in two planes with a frame rate of 3...
January 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28102670/microfluidization-of-graphite-and-formulation-of-graphene-based-conductive-inks
#3
Panagiotis G Karagiannidis, Stephen A Hodge, Lucia Lombardi, Flavia Tomarchio, Nicolas Decorde, Silvia Milana, Ilya Goykhman, Yang Su, Steven V Mesite, Duncan N Johnstone, Rowan K Leary, Paul A Midgley, Nicola M Pugno, Felice Torrisi, Andrea C Ferrari
We report the exfoliation of graphite in aqueous solutions under high shear rate turbulent flow conditions, with a 100\% exfoliation yield. The material is stabilized without centrifugation at concentrations up to 100 g/L using carboxymethylcellulose sodium salt to formulate conductive printable inks. The sheet resistance of blade coated films is below~2Ω/□. This is a simple and scalable production route for conductive inks for large area printing in flexible electronics.
January 19, 2017: ACS Nano
https://www.readbyqxmd.com/read/28102332/dynamic-modeling-of-uteroplacental-blood-flow-in-iugr-indicates-vortices-and-elevated-pressure-in-the-intervillous-space-a-pilot-study
#4
Christian J Roth, Eva Haeussner, Tanja Ruebelmann, Franz V Koch, Christoph Schmitz, Hans-Georg Frank, Wolfgang A Wall
Ischemic placental disease is a concept that links intrauterine growth retardation (IUGR) and preeclampsia (PE) back to insufficient remodeling of uterine spiral arteries. The rheological consequences of insufficient remodeling of uterine spiral arteries were hypothesized to mediate the considerably later manifestation of obstetric disease. However, the micro-rheology in the intervillous space (IVS) cannot be examined clinically and rheological animal models of the human IVS do not exist. Thus, an in silico approach was implemented to provide in vivo inaccessible data...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28091520/phantom-vortices-hidden-angular-momentum-in-ultracold-dilute-bose-einstein-condensates
#5
Storm E Weiner, Marios C Tsatsos, Lorenz S Cederbaum, Axel U J Lode
Vortices are essential to angular momentum in quantum systems such as ultracold atomic gases. The existence of quantized vorticity in bosonic systems stimulated the development of the Gross-Pitaevskii mean-field approximation. However, the true dynamics of angular momentum in finite, interacting many-body systems like trapped Bose-Einstein condensates is enriched by the emergence of quantum correlations whose description demands more elaborate methods. Herein we theoretically investigate the full many-body dynamics of the acquisition of angular momentum by a gas of ultracold bosons in two dimensions using a standard rotation procedure...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28090122/effect-of-static-vs-dynamic-imaging-on-particle-transport-in-ct-based-numerical-models-of-human-central-airways
#6
Shinjiro Miyawaki, Eric A Hoffman, Ching-Long Lin
Advances in quantitative computed tomography (CT) has provided methods to assess the detailed structure of the pulmonary airways and parenchyma, providing the means of applying computational fluid dynamics-based modeling to better understand subject-specific differences in structure-to-function relationships. Most of the previous numerical studies, seeking to predict patterns of inhaled particle deposition, have considered airway geometry and regional ventilation derived from static images. Because geometric alterations of the airway and parenchyma associated with regional ventilation may greatly affect particle transport, we have sought to investigate the effect of rigid vs...
October 2016: Journal of Aerosol Science
https://www.readbyqxmd.com/read/28087421/physiology-anaerobes-and-the-origin-of-mitosing-cells-50-years-on
#7
William F Martin
Endosymbiotic theory posits that some organelles or structures of eukaryotic cells stem from free-living prokaryotes that became endosymbionts within a host cell. Endosymbiosis has a long and turbulent history of controversy and debate going back over 100 years. The 1967 paper by Lynn Sagan (later Lynn Margulis) forced a reluctant field to take endosymbiotic theory seriously and to incorporate it into the fabric of evolutionary thinking. Margulis envisaged three cellular partners associating in series at eukaryotic origin: the host (an engulfing bacterium), the mitochondrion (a respiring bacterium), and the flagellum (a spirochaete), with lineages descended from that flagellated eukaryote subsequently acquiring plastids from cyanobacteria, but on multiple different occasions in her 1967 account...
January 10, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28081322/does-cpap-treatment-affect-the-voice
#8
Güleser Saylam, Mustafa Şahin, Dilek Demiral, Ömer Bayır, Melike Bağnu Yüceege, Emel Çadallı Tatar, Mehmet Hakan Korkmaz
BACKGROUND/AIM: The aim of this study was to investigate alterations in voice parameters among patients using continuous positive airway pressure (CPAP) for the treatment of obstructive sleep apnea syndrome. MATERIALS AND METHODS: Patients with an indication for CPAP treatment without any voice problems and with normal laryngeal findings were included and voice parameters were evaluated before and 1 and 6 months after CPAP. Videolaryngostroboscopic findings, a self-rated scale (Voice Handicap Index-10, VHI-10), perceptual voice quality assessment (GRBAS: grade, roughness, breathiness, asthenia, strain), and acoustic parameters were compared...
December 20, 2016: Turkish Journal of Medical Sciences
https://www.readbyqxmd.com/read/28081100/digital-equalization-of-time-delay-array-receivers-on-coherent-laser-communications
#9
Aniceto Belmonte
Field conjugation arrays use adaptive combining techniques on multi-aperture receivers to improve the performance of coherent laser communication links by mitigating the consequences of atmospheric turbulence on the down-converted coherent power. However, this motivates the use of complex receivers as optical signals collected by different apertures need to be adaptively processed, co-phased, and scaled before they are combined. Here, we show that multiple apertures, coupled with optical delay lines, combine retarded versions of a signal at a single coherent receiver, which uses digital equalization to obtain diversity gain against atmospheric fading...
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28081097/laser-beam-self-focusing-in-turbulent-dissipative-media
#10
B Hafizi, J R Peñano, J P Palastro, R P Fischer, G DiComo
A high-power laser beam propagating through a dielectric in the presence of fluctuations is subject to diffraction, dissipation, and optical Kerr nonlinearity. A method of moments was applied to a stochastic, nonlinear enveloped wave equation to analyze the evolution of the long-term spot radius. For propagation in atmospheric turbulence described by a Kolmogorov-von Kármán spectral density, the analysis was benchmarked against field experiments in the low-power limit and compared with simulation results in the high-power regime...
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28081089/direct-comparison-of-two-dimensional-and-three-dimensional-laser-induced-fluorescence-measurements-on-highly-turbulent-flames
#11
Lin Ma, Qingchun Lei, Tyler Capil, Stephen D Hammack, Campbell D Carter
This Letter reports the first direct comparison between two-dimensional (2D) and three-dimensional (3D) laser-induced fluorescence (LIF) applied to highly turbulent flames, with the goal of experimentally illustrating the capabilities and limitations of volumetric LIF (VLIF). To accomplish these goals, planar LIF (PLIF) and VLIF measurements were simultaneously performed on turbulent flames based on the CH radical. The PLIF measurements imaged a planar cross-section of the target flames across a 2D field-of-view (FOV) of 42  mm×42  mm...
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28081082/seedless-velocimetry-at-100%C3%A2-%C3%A2-khz-with-picosecond-laser-electronic-excitation-tagging
#12
Naibo Jiang, Jason G Mance, Mikhail N Slipchenko, Josef J Felver, Hans U Stauffer, Tongxun Yi, Paul M Danehy, Sukesh Roy
Picosecond-laser electronic-excitation tagging (PLEET), a seedless picosecond-laser-based velocimetry technique, is demonstrated in non-reactive flows at a repetition rate of 100 kHz with a 1064 nm, 100 ps burst-mode laser. The fluorescence lifetime of the PLEET signal was measured in nitrogen, and the laser heating effects were analyzed. PLEET experiments with a free jet of nitrogen show the ability to measure multi-point flow velocity fluctuations at a 100 kHz detection rate or higher. Both spectral and dynamic mode decomposition analyses of velocity on a Ma=0...
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28077881/a-pilot-study-of-penile-hemodynamics-in-men-with-penile-curvatures
#13
A A Zaazaa, I Fathy, O Ayman, A Hassanin, H Ghanem
Penile curvature (PC) is bothersome to the patient. PC is either congenital or acquired. In most of the circulatory system, blood flows in a laminar profile with minimal energy expenditure. When a fluid passes in a curved tube, the laminar profile is disturbed and changed into a turbulent flow. It increases the energy expenditure and reduces the flow. Turbulent flow may have a role in the development of an atherosclerotic plaque and in localizing its site. The aim of this research was to study penile hemodynamics before and after correction of PC...
January 12, 2017: International Journal of Impotence Research
https://www.readbyqxmd.com/read/28077852/growth-and-turbulence-in-the-container-contained-bion-s-continuing-legacy-edited-by-howard-b-levine-and-lawrence-j-brown-routledge-2013-323pp
#14
Virginia Rachmani
No abstract text is available yet for this article.
December 2016: American Journal of Psychoanalysis
https://www.readbyqxmd.com/read/28073560/an-alternative-explanation-for-cyanobacterial-scum-formation-and-persistence-by-oxygenic-photosynthesis
#15
E Aparicio Medrano, R E Uittenbogaard, B J H van de Wiel, L M Dionisio Pires, H J H Clercx
The cause of persistent cyanobacteria scum formation in lakes is an unresolved subject. Scum refers to the event in which cyanobacteria are at the water surface of a lake. Factors like low turbulence levels, long day-light, high water temperatures and the buoyant capacity of cyanobacterial cells play a role in the occurrence of scums. However, they do not explain why scums are observed at periods during the day when according to theory they should have disappeared into the deeper water layers. In this study, we present an alternative explanation...
December 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073538/margalef-revisited-a-new-phytoplankton-mandala-incorporating-twelve-dimensions-including-nutritional-physiology
#16
Patricia M Glibert
Building on the classic depiction of the progression from a diatom to a dinoflagellate bloom as a function of nutrients and turbulence, known as the "Margalef mandala", a new conceptual model or mandala is presented here. The new mandala maps twelve response or effects traits, or environmental characteristics, related to different phytoplankton functional types: (1) relative preference for chemically reduced vs chemically oxidized forms of nitrogen; (2) relative availability of inorganic nitrogen and phosphorus; (3) adaptation to high vs low light and the tendency to be autotrophic vs mixotrophic; (4) cell motility; (5) environmental turbulence; (6) pigmentation quality; (7) temperature; (8) cell size; (9) relative growth rate; (10) relative production of bioactive compounds such as toxins or reactive oxygen species (ROS); (11) r vs K strategy; and (12) fate of the production in terms of grazing...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073534/turbulence-increases-the-risk-of-microcystin-exposure-in-a-eutrophic-lake-lake-taihu-during-cyanobacterial-bloom-periods
#17
Jian Zhou, Boqiang Qin, Xiaoxia Han, Lin Zhu
Toxic cyanobacterial harmful algal blooms (CyanoHABs) have posed serious water use and public health threats because of the toxins they produce, such as the microcystins (MCs). The direct physical effects of turbulence on MCs, however, have not yet been addressed and is still poorly elucidated. In this study, a 6-day mesocosm experiment was carried out to evaluate the effects of wind wave turbulence on the competition of toxic Microcystis and MCs production in highly eutrophicated and turbulent Lake Taihu, China...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073451/implications-of-turbulent-flow-in-connecting-capillaries-used-in-high-performance-liquid-chromatography
#18
John Halvorson, Abraham M Lenhoff, Monika Dittmann, Dwight R Stoll
The ongoing movement in HPLC toward the use of small columns packed with small particles for high speed separations results in eluted peaks with very small volumetric variances. Avoiding degradation of separation performance under these conditions requires careful consideration of all sources of extra-column peak dispersion. Recent trends towards decreased diameters of connecting capillaries and increased flow rates for analytical-scale separations can result in Reynolds numbers that exceed 2000. This raises the possibility of a transition from laminar to turbulent flow, thereby resulting in a higher than expected pressure drop across the capillary at a given flow rate...
December 31, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28073438/individual-based-modelling-of-the-development-and-transport-of-a-karenia-mikimotoi-bloom-on-the-north-west-european-continental-shelf
#19
P A Gillibrand, B Siemering, P I Miller, K Davidson
In 2006, a large and prolonged bloom of the dinoflagellate Karenia mikimotoi occurred in Scottish coastal waters, causing extensive mortalities of benthic organisms including annelids and molluscs and some species of fish (Davidson et al., 2009). A coupled hydrodynamic-algal transport model was developed to track the progression of the bloom around the Scottish coast during June-September 2006 and hence investigate the processes controlling the bloom dynamics. Within this individual-based model, cells were capable of growth, mortality and phototaxis and were transported by physical processes of advection and turbulent diffusion, using current velocities extracted from operational simulations of the MRCS ocean circulation model of the North-west European continental shelf...
March 2016: Harmful Algae
https://www.readbyqxmd.com/read/28069770/recent-advances-in-high-capacity-free-space-optical-and-radio-frequency-communications-using-orbital-angular-momentum-multiplexing
#20
REVIEW
Alan E Willner, Yongxiong Ren, Guodong Xie, Yan Yan, Long Li, Zhe Zhao, Jian Wang, Moshe Tur, Andreas F Molisch, Solyman Ashrafi
There is a continuing growth in the demand for data bandwidth, and the multiplexing of multiple independent data streams has the potential to provide the needed data capacity. One technique uses the spatial domain of an electromagnetic (EM) wave, and space division multiplexing (SDM) has become increasingly important for increased transmission capacity and spectral efficiency of a communication system. A subset of SDM is mode division multiplexing (MDM), in which multiple orthogonal beams each on a different mode can be multiplexed...
February 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
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