keyword
MENU ▼
Read by QxMD icon Read
search

vortex

keyword
https://www.readbyqxmd.com/read/28539633/ultrashort-vortex-from-a-gaussian-pulse-an-achromatic-interferometric-approach
#1
Dinesh N Naik, Nabil A Saad, D Narayana Rao, Nirmal K Viswanathan
The more than a century old Sagnac interferometer is put to first of its kind use to generate an achromatic single-charge vortex equivalent to a Laguerre-Gaussian beam possessing orbital angular momentum (OAM). The interference of counter-propagating polychromatic Gaussian beams of beam waist ωλ with correlated linear phase (ϕ 0  ≥ 0.025 λ) and lateral shear (y 0  ≥ 0.05 ωλ) in orthogonal directions is shown to create a vortex phase distribution around the null interference. Using a wavelength-tunable continuous-wave laser the entire range of visible wavelengths is shown to satisfy the condition for vortex generation to achieve a highly stable white-light vortex with excellent propagation integrity...
May 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28539482/multi-cored-vortices-support-function-of-slotted-wing-tips-of-birds-in-gliding-and-flapping-flight
#2
Marco KleinHeerenbrink, L Christoffer Johansson, Anders Hedenström
Slotted wing tips of birds are commonly considered an adaptation to improve soaring performance, despite their presence in species that neither soar nor glide. We used particle image velocimetry to measure the airflow around the slotted wing tip of a jackdaw (Corvus monedula) as well as in its wake during unrestrained flight in a wind tunnel. The separated primary feathers produce individual wakes, confirming a multi-slotted function, in both gliding and flapping flight. The resulting multi-cored wingtip vortex represents a spreading of vorticity, which has previously been suggested as indicative of increased aerodynamic efficiency...
May 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28539480/identification-of-vortex-structures-in-a-cohort-of-204-intracranial-aneurysms
#3
Nicole Varble, Gabriel Trylesinski, Jianping Xiang, Kenneth Snyder, Hui Meng
An intracranial aneurysm (IA) is a cerebrovascular pathology that can lead to death or disability if ruptured. Abnormal wall shear stress (WSS) has been associated with IA growth and rupture, but little is known about the underlying flow physics related to rupture-prone IAs. Previous studies, based on analysis of a few aneurysms or partial views of three-dimensional vortex structures, suggest that rupture is associated with complex vortical flow inside IAs. To further elucidate the relevance of vortical flow in aneurysm pathophysiology, we studied 204 patient IAs (56 ruptured and 148 unruptured)...
May 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28530287/microfluidic-self-assembly-of-folate-targeted-monomolecular-sirna-lipid-nanoparticles
#4
R Krzysztoń, B Salem, D J Lee, G Schwake, E Wagner, J O Rädler
Non-viral delivery of nucleic acids for therapies based on RNA interference requires a rational design and optimal self-assembly strategies. Nucleic acid particles need to be small, stable and functional in terms of selective cell uptake and controlled release of encapsulated nucleic acids. Here we report on small (∼38 nm) monomolecular nucleic acid/lipid particles (mNALPs) that contain single molecules of short double-stranded oligonucleotides covered by a tight, highly curved lipid bilayer. The particles consist of DOPE, DOTAP, DOPC and DSPE-PEG(2000) and are assembled with 21 bp double-stranded DNA or small interfering RNA by solvent exchange on a hydrodynamic-focusing microfluidic chip...
May 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/28529384/the-pelskin-project-part-v-towards-the-control-of-the-flow-around-aerofoils-at-high-angle-of-attack-using-a-self-activated-deployable-flap
#5
Marco E Rosti, Laura Kamps, Christoph Bruecker, Mohammad Omidyeganeh, Alfredo Pinelli
During the flight of birds, it is often possible to notice that some of the primaries and covert feathers on the upper side of the wing pop-up under critical flight conditions, such as the landing approach or when stalking their prey (see Fig. 1) . It is often conjectured that the feathers pop up plays an aerodynamic role by limiting the spread of flow separation . A combined experimental and numerical study was conducted to shed some light on the physical mechanism determining the feathers self actuation and their effective role in controlling the flow field in nominally stalled conditions...
2017: Meccanica
https://www.readbyqxmd.com/read/28529383/the-pelskin-project-part-ii-investigating-the-physical-coupling-between-flexible-filaments-in-an-oscillating-flow
#6
Alistair Revell, Joseph O'Connor, Abhishek Sarkar, Cuicui Li, Julien Favier, Laura Kamps, Christoph Brücker
The fluid-structure interaction mechanisms of a coating composed of flexible flaps immersed in a periodically oscillating channel flow is here studied by means of numerical simulation, employing the Euler-Bernoulli equations to account for the flexibility of the structures. A set of passively actuated flaps have previously been demonstrated to deliver favourable aerodynamic impact when attached to a bluff body undergoing periodic vortex shedding. As such, the present configuration is identified to provide a useful test-bed to better understand this mechanism, thought to be linked to experimentally observed travelling waves...
2017: Meccanica
https://www.readbyqxmd.com/read/28525867/evaluation-of-alternative-environmentally-friendly-matrix-solid-phase-dispersion-solid-supports-for-the-simultaneous-extraction-of-15-pesticides-of-different-chemical-classes-from-drinking-water-treatment-sludge
#7
Karina Lotz Soares, Maristela Barnes Rodrigues Cerqueira, Sergiane Souza Caldas, Ednei Gilberto Primel
This study describes the development, optimization and validation of a method for the extraction of 15 pesticides of different chemical classes in drinking water treatment sludge (DWTS) by vortex-assisted Matrix Solid Phase Dispersion (MSPD) with determination by gas chromatography coupled to mass spectrometry. It focused on the application of alternative and different solid supports to the extraction step of the MSPD. The main parameters that influenced the extraction were studied in order to obtain better recovery responses...
May 12, 2017: Chemosphere
https://www.readbyqxmd.com/read/28515570/association-between-hemodynamic-modifications-and-clinical-outcome-of-intracranial-aneurysms-treated-using-flow-diverters
#8
Nikhil Paliwal, Robert J Damiano, Jason M Davies, Adnan H Siddiqui, Hui Meng
Treatment of intracranial aneurysms (IAs) has been revolutionized by the advent of endovascular Flow Diverters (FDs), which disrupt blood flow within the aneurysm to induce pro-thrombotic conditions, and serves as a scaffold for endothelial ingrowth and arterial remodeling. Despite good clinical success of FDs, complications like incomplete occlusion and post-treatment rupture leading to subarachnoid hemorrhage have been reported. In silico computational fluid dynamic analysis of the pre- and post-treated geometries of IA patients can shed light on the contrasting blood hemodynamics associated with different clinical outcomes...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28513472/experimental-and-numerical-studies-of-beetle-inspired-flapping-wing-in-hovering-flight
#9
Tien Van Truong, Tuyen Quang Le, Hoon Cheol Park, Doyoung Byun
In this paper, we measure unsteady forces and visualize 3D vortices around a beetle-like flapping wing model in hovering flight by experiment and numerical simulation. The measurement of unsteady forces and flow patterns around the wing were conducted using a dynamically scaled wing model in the mineral-oil tank. The wing kinematics were directly derived from the experiment of a real beetle. The 3D flow structures of the flapping wing were captured by using air bubble visualization while forces were measured by a sensor attached at the wing base...
May 17, 2017: Bioinspiration & Biomimetics
https://www.readbyqxmd.com/read/28508858/onset-of-meso-scale-turbulence-in-active-nematics
#10
Amin Doostmohammadi, Tyler N Shendruk, Kristian Thijssen, Julia M Yeomans
Meso-scale turbulence is an innate phenomenon, distinct from inertial turbulence, that spontaneously occurs at low Reynolds number in fluidized biological systems. This spatiotemporal disordered flow radically changes nutrient and molecular transport in living fluids and can strongly affect the collective behaviour in prominent biological processes, including biofilm formation, morphogenesis and cancer invasion. Despite its crucial role in such physiological processes, understanding meso-scale turbulence and any relation to classical inertial turbulence remains obscure...
May 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28508524/co2-triggered-co-assembled-nanotubes-with-controlled-chirality-through-a-co2-bubble-induced-vortex
#11
Ling Zhang, Laicheng Zhou, Na Xu, Zhenjie Ouyang
The design of co-organized nanotube systems with controlled nanoscale chirality that are responsive to the liquid flow field induced by bubbling external gas in aqueous media remains a significant challenge. Here, we report success in utilizing the liquid vortexes induced by bubbling carbon dioxide (CO2) gas to stimulate the formation of nanotubes with controlled chirality based on the co-assembly of two kinds of achiral cationic building blocks in aqueous solution. The results reveal that CO2-triggered nanotube formation occurs via the formation of short helical ribbons and short tubules as metastable intermediate structures, and via transition from short tubules to long tubules based on chirality match self-assembly...
May 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28505771/counterexamples-to-moffatt-s-statements-on-vortex-knots
#12
Oleg Bogoyavlenskij
One of the well-known problems of hydrodynamics is studied: the problem of classification of vortex knots for ideal fluid flows. In the literature there are known Moffatt statements that all torus knots K_{m,n} for all rational numbers m/n (0<m/n<∞) are realized as vortex knots for each one of the considered axisymmetric fluid flows. We prove that actually such a uniformity does not exist because it does not correspond to the facts. Namely, we derive a complete classification of all vortex knots realized for the fluid flows studied by Moffatt and demonstrate that the real structure of vortex knots is much more rich because the sets of mutually nonisotopic vortex knots realized for different axisymmetric fluid flows are all different...
April 2017: Physical Review. E
https://www.readbyqxmd.com/read/28502468/magnetically-assisted-matrix-solid-phase-dispersion-for-extraction-of-parabens-from-breast-milks
#13
Mina Fotouhi, Shahram Seidi, Maryam Shanehsaz, Mohammad Taghi Naseri
In the present work, magnetically assisted matrix solid phase dispersion (MA-MSPD) was used as an efficient solid phase extraction method. MA-MSPD followed by a dispersive liquid-liquid microextraction (DLLME) was applied for determination of parabens in breast milks. The analysis were performed using LC-UV and LC-MS/MS. Poly(indole-thiophene) coated magnetic graphene oxide (MGO@PIT) was synthesized, characterized and used as the sorbent. Na2SO4 was used as the drying salt as well as matrix dispersing agent...
May 5, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28500487/high-frame-rate-vector-flow-imaging-of-the-carotid-bifurcation
#14
REVIEW
Alfredo Goddi, Chandra Bortolotto, Ilaria Fiorina, Maria Vittoria Raciti, Marianna Fanizza, Elena Turpini, Giulia Boffelli, Fabrizio Calliada
Carotid artery atherosclerotic disease is still a significant cause of cerebrovascular morbidity and mortality. A new angle-independent technique, measuring and visualizing blood flow velocities in all directions, called vector flow imaging (VFI) is becoming available from several vendors. VFI can provide more intuitive and quantitative imaging of vortex formation, which is not clearly distinguishable in the color Doppler image. VFI, as quantitative method assessing disturbed flow patterns of the carotid bifurcation, has the potential to allow better understanding of the diagnostic value of complex flow and to enhance risk stratification...
May 12, 2017: Insights Into Imaging
https://www.readbyqxmd.com/read/28499150/effect-of-yarn-structure-on-wicking-and-its-impact-on-bloodstain-pattern-analysis-bpa-on-woven-cotton-fabrics
#15
Xingyu Li, Jingyao Li, Stephen Michielsen
Bloodstain pattern analysis (BPA) of bloodstains on hard, non-porous surfaces has found widespread use in crime scene analysis and reconstruction for violent crimes in which bloodshed occurs. At many violent crime scenes, bloody clothing is also found and may be analyzed. However, to date, there are no definitive methods for analyzing bloodstains on textiles, even for simple drip stains. There are two major classes of textiles used for apparel and household textiles, weaves and knits. In this article, drip stains on two 100% cotton plain weave fabrics representative of bed sheets are analyzed...
April 27, 2017: Forensic Science International
https://www.readbyqxmd.com/read/28490150/a-simple-and-sensitive-vortex-assisted-ionic-liquid-dispersive-microextraction-and-spectrophotometric-determination-of-selenium-in-food-samples
#16
Esra Bağda, Mustafa Tüzen
In the present study, a novel and eco-friendly vortex-assisted ionic liquid-based microextraction method was developed for the determination of selenium in food. The microextraction method is based on the liberation of iodine in the presence of selenium; the liberated iodine reacts with I(-) to form I3(-). Anionic I3(-) reacts with cationic crystal violet dye, and the product is extracted into 1-hexyl-3-methylimidazolium hexafluorophosphate phase in the presence of Triton X-114. The proposed method is linear in the range of 2...
October 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28488167/a-generic-label-free-microfluidic-microobject-sorter-using-a-magnetic-elastic-diverter
#17
Jiachen Zhang, Onaizah Onaizah, Amir Sadri, Eric Diller
Cell sorters play important roles in biological and medical applications, such as cellular behavior study and disease diagnosis and therapy. This work presents a label-free microfluidic sorter that has a downstream-pointing magnetic elastic diverter. Different with most existing magnetic sorters, the proposed device does not require the target microobjects to be intrinsically magnetic or coated with magnetic particles, giving users more flexibility in sorting criteria. The diverter is wirelessly deformed by an applied magnetic field, and its deformation induces a fluid vortex that sorts incoming microobjects, e...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28487122/guanidinium-ionic-liquid-based-surfactants-as-low-cytotoxic-extractants-analytical-performance-in-an-in-situ-dispersive-liquid-liquid-microextraction-method-for-determining-personal-care-products
#18
Idaira Pacheco-Fernández, Verónica Pino, Juan H Ayala, Ana M Afonso
The IL-based surfactant octylguanidinium chloride (C8Gu-Cl) was designed and synthetized with the purpose of obtaining a less harmful surfactant: containing guanidinium as core cation and a relatively short alkyl chain. Its interfacial and aggregation behavior was evaluated through conductivity and fluorescence measurements, presenting a critical micelle concentration value of 42.5 and 44.6mmolL(-1), respectively. Cytotoxicity studies were carried out with C8Gu-Cl and other IL-based and conventional surfactants, specifically the analogue 1-octyl-3-methylimidazolium chloride (C8MIm-Cl), and other imidazolium- (C16MIm-Br) and pyridinium- (C16Py-Cl) based surfactants, together with the conventional cationic CTAB and the conventional anionic SDS...
May 1, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28485424/helicity-locking-of-chiral-light-emitted-from-a-plasmonic-nanotaper
#19
Denis Garoli, Pierfrancesco Zilio, Francesco De Angelis, Yuri Gorodetski
Surface plasmon waves carry an intrinsic transverse spin, which is locked to its propagation direction. Apparently, when a singular plasmonic mode is guided on a conic surface this spin-locking may lead to a strong circular polarization of the far-field emission. Specifically, a plasmonic vortex excited on a flat metal surface propagates on an adiabatically tapered gold nanocone where the mode accelerates and finally beams out from the tip apex. The helicity of this beam is shown to be single-handed and stems solely from the transverse spin-locking of the helical plasmonic wave-front...
May 9, 2017: Nanoscale
https://www.readbyqxmd.com/read/28481499/direct-observation-of-current-induced-motion-of-a-3d-vortex-domain-wall-in-cylindrical-nanowires
#20
Yurii P Ivanov, Andrey Chuvilin, Sergei Lopatin, Hanan Mohammed, Jurgen Kosel
The current-induced dynamics of 3D magnetic vortex domain walls in cylindrical Co/Ni nanowires are revealed experimentally using Lorentz microscopy and theoretically using micromagnetic simulations. We demonstrate that a spin-polarized electric current can control the reversible motion of 3D vortex domain walls, which travel with a velocity of a few hundred meters per second. This finding is a key step in establishing fast, high-density memory devices based on vertical arrays of cylindrical magnetic nanowires...
May 15, 2017: ACS Applied Materials & Interfaces
keyword
keyword
20207
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"