Filament Sizes Research Articles

Dependence of divertor turbulence on plasma density and current in TCV

Abstract To reliably predict the distribution of heat and particle fluxes at the target plates of tokamaks, a comprehensive understanding of turbulence throughout the entire Scrape-Off-Layer (SOL) is imperative. This study examines divertor turbulence systematically across a broad parameter range on the TCV tokamak, including variations in magnetic field direction, plasma current I p ∈ [ 140 , 320 ] kA, edge safety factor q 95 ∈ [ 2.6 , 4.7 ] and Greenwald fraction f G ∈ [ 0.18 , 0.6 ] . The TCV X-point Gas Puff Imaging (GPI) system is used to measure 2D filament properties in the inner and outer divertor region. The fluctuation levels in the divertor are found to strongly increase with density (to 80% over most of the SOL) while remaining insensitive to I p . The previously identified divertor-localized filaments (DLF), located on the bad curvature side of the outer divertor leg, are found to be a common feature on TCV, while no filaments are observed in the PFR. DLFs are present over most of the parameter space and in both field directions. However, they are absent, or appear only closer to the target, for sufficiently large Λ div ≳ 10 or q 95 ≳ 3.7 . Across both I p and f G scans, some clear trends with Λ div are found for divertor filament sizes and velocities, and with target fall-off lengths of density and heat flux profiles at the outer target. This study provides important experimental insights to turbulent transport in the divertor also for comparison with self-consistent, turbulence simulations and extrapolation to future reactor conditions.

Simultaneous degradation of cyanobacteria and cyanotoxins by catalytic wet peroxide oxidation: Impact of morphology and growth stage

The widespread proliferation of potentially toxic cyanobacteria in source waters for drinking water treatment plants (DWTPs) presents a pressing contemporary challenge. Although catalytic wet peroxide oxidation (CWPO) has been recognized as a highly effective and environmentally friendly technology for removing cyanotoxins from water, the simultaneous degradation of cyanobacteria and cyanotoxins has been scarcely investigated. Considering their great morphological diversity, in this work, the impact of the presence of pure strains of several species of toxic and non-toxic cyanobacteria on the degradation of relevant cyanotoxins has been evaluated considering also the main stages of their life cycle. In each studied scenario, achieving a full eradication of the cyanobacteria also led to the complete elimination of the cyanotoxin, including both intra and extracellular fractions. Morphological factors, including filament and cell sizes, play a crucial role in the efficiency of the process. Small cells and long filaments entail a higher presence of particulate organic matter, which consumes hydroxyl radicals considerably in competence with the cyanotoxin degradation. Moreover, the growth stage emerges as a pivotal factor in understanding the CWPO process performance, with cyanobacteria in their early life stages, exhibiting more pronounced interference compared to later stages, probably due to their higher cell viability and accelerated metabolism. All these understandings are essential for the successful implementation of the technology in treating surface waters affected by toxic cyanobacterial blooms.

Sun-as-a-star Observations of Obscuration Dimmings Caused by Filament Eruptions

Filament eruptions often lead to coronal mass ejections (CMEs) on the Sun and are one of the most energetic eruptive phenomena in the atmospheres of other late-type stars. However, the detection of filament eruptions and CMEs on stars beyond the solar system is challenging. Here, we present six filament eruption cases on the Sun and show that filament material obscuring part of the solar disk can cause detectable dimming signatures in Sun-as-a-star flux curves of He ii 304 Å. Those filament eruptions have similar morphological features, originating from small filaments inside active regions and subsequently strongly expanding to obscure large areas of the solar disk or the bright flare regions. We have tracked the detailed evolution of six obscuration dimmings and estimated the dimming properties, such as dimming depths, dimming areas, and duration. The largest dimming depth among the six events under study is 6.2% accompanied by the largest dimming area of 5.6% of the solar disk area. Other events have maximum dimming depths in a range of around 1%–3%, with maximum areas varying between about 3%–4% of the solar disk area. The duration of the dimming spans from around 0.4–7.0 hr for the six events under study. A positive correlation was found between the dimming depth and area, which may help to set constraints on the filament sizes in stellar observations.

Reliability effects of lateral filament confinement by nano-scaling the oxide in memristive devices.

Write-variability and resistance instability are major reliability concerns impeding implementation of oxide-based memristive devices in neuromorphic systems. The root cause of the reliability issues is the stochastic nature of conductive filament formation and dissolution, whose impact is particularly critical in the high resistive state (HRS). Optimizing the filament stability requires mitigating diffusive processes within the oxide, but these are unaffected by conventional electrode scaling. Here we propose a device design that laterally confines the switching oxide volume and thus the filament to 10 nm, which yields reliability improvements in our measurements and simulations. We demonstrate a 50% decrease in HRS write-variability for an oxide nano-fin device in our full factorial analysis of modulated current-voltage sweeps. Furthermore, we use ionic noise measurements to quantify the HRS filament stability against diffusive processes. The laterally confined filaments exhibit a change in the signal-to-noise ratio distribution with a shift to higher values. Our complementing kinetic Monte Carlo simulation of oxygen vacancy (re-)distribution for confined filaments shows improved noise behavior and elucidates the underlying physical mechanisms. While lateral oxide volume scaling down to filament sizes is challenging, our efforts motivate further examination and awareness of filament confinement effects in regards to reliability.

Ic measurement of twisted multifilamentary MgB2 wires with non-magnetic sheath over a wide range of temperatures and fields

All-superconducting rotating machines have the potential for meeting the high power density and high efficiency required for electrical aircraft applications. However, very high AC loss encountered in superconducting armature windings could hinder their development. Multifilamentary MgB2 wires are one of the promising candidates for the stator windings, due to their potentially low AC loss properties with small filament size and twist pitches. As the first step, the dependence of critical current and n-value on magnetic fields and temperatures Ic(B, T) and n(B,T), which are basic input parameters for AC loss simulation, needs to be measured. In this work, we present transport Ic measurements in three non-magnetic multifilamentary MgB2 wires (MgB2/Nb/CuNi/CuZn): one large wire with a 0.70 mm diameter and 25 mm twist pitch, and two small wires with a 0.48 mm diameter each and a 10 mm and 30 mm twist pitch respectively. A four-probe direct current method is used to measure Ic of the MgB2 wires with variations in temperature (15 – 35 K) and magnetic field (0 – 5.5 T). Full Ic data for the small wire with 10 mm twist pitch was obtained, and the n-values were mostly less than 20. While the Ic data for the large wire at low fields was more limited due to heating, the n-values were higher and could be up to around 100. The difference is attributed to the different filament sizes. Experiments also found that there is no significant hysteresis in the transport critical current measured by decreasing or increasing magnetic fields due to the non-magnetic sheaths. This non-hysteretic characteristic is critical for lowering AC loss because the additional losses from magnetic sheaths can be eliminated. From the magnetic-field dependence of critical current density, an empirical expression has been developed that provides suitable extrapolations to lower fields for the large wire.

Optimizing intraluminal monofilament model of ischemic stroke in middle-aged Sprague–Dawley rats

Intraluminal monofilament model of middle cerebral artery occlusion (MCAO) is widely adopted for ischemic stroke; and Sprague-Dawley (SD) rats are commonly used rodents for preclinical research. Due to the paucity of information on the appropriate monofilament size for inducing MCAO in SD rats and the importance of including middle-aged models in ischemic stroke studies, we aimed to: (i). determine an appropriate Doccol® monofilament size for middle-aged male SD rats which weighed > 500g following 24-h transient MCAO survival as well as (ii). demonstrate the optimal Doccol® filament size for middle-aged males (≤ 500g) and females (273-300g) while using young adult male SD rats (372-472g) as control for severity of infarct volume following 7-days post-MCAO. All rats were subjected to 90-min transient MCAO. We show that 0.43mm Doccol® monofilament size is more appropriate to induce large infarct lesion and optimal functional deficit when compared to 0.45mm and 0.47mm at 24h post-MCAO. Our data on infarct volumes at 7days post-MCAO as well as the observed weight loss and functional deficits at post-MCAO days 1, 3 and 7 demonstrate that 0.41mm, 0.37mm and 0.39mm are optimal Doccol® filament sizes for middle-aged male (477.3 ± 39.61g) and female (302.6 ± 26.28g) as well as young-adult male (362.2 ± 28.38g) SD rats, respectively.

Abnormal Laryngopharyngeal Sensation in Adductor Laryngeal Dystonia Compared to Healthy Controls.

Laryngeal sensory abnormality has been implicated as a component of adductor laryngeal dystonia (AdLD). The study objective was to assess laryngopharyngeal sensation in AdLD utilizing a calibrated, tactile aesthesiometer to deliver differential stimuli to lateral pyriform sinus (LPS), aryepiglottic fold (AEF), and false vocal fold (FVF). Patients with known Botox-responsive AdLD underwent sensory testing using a previously-validated methodology involving calibrated tactile stimuli (6-0, 5-0, 4.5-0, 4-0 nylon monofilaments). Laryngeal adductor reflex (LAR) and participant-rated perceptual strength of stimulI were evaluated. Responses were compared to normative controls (n=33). Two-samples, Mann-Whitney and Fisher exact tests compared mean strength ratings and LAR between AdLD and control groups. Mixed-effects logistic regression and linear models assessed association of filament size, stimulus site, age, sex, and LD status on LAR and perceptual strength rating respectively. Thirteen AdLD patients (nine women, mean age 60+/-15 years) completed testing. Average LAR response rates were higher amongst all filament sizes in AdLD versus controls at LPS (56.3% vs. 35.7%) and AEF (96.1% vs. 70.2%) with comparable rates at FVF (90.2% vs. 91.7%). AdLD had 3.3 times the odds of observed LAR compared to controls (p=0.005), but differences in subjective detection of stimuli, perceptual strength ratings, and cough/gag rates were insignificant on multivariate modeling (p > 0.05). This is the first study to objectively assess laryngopharyngeal sensation in AdLD. Findings demonstrated increased laryngopharyngeal sensation in AdLD compared to controls. The identification of increased laryngeal hypersensitivity in these patients may improve understanding of AdLD pathophysiology and identify future targets for intervention. 2 Laryngoscope, 133:2271-2278, 2023.

Anisian (Middle Triassic) stromatolites from Southwest China: Biogeological features and implications for variations of filament size and diversity of Triassic cyanobacteria

This study documents new stromatolite deposits from the Anisian succession of the Guanling Formation in the Boyun section of eastern Yunnan Province, southwestern China. The Boyun stromatolites are characterized by undulating laminations, which yield a variety of biostructures and abiotic grains, such as cyanobacteria Bevocastria and Renalcis, microclots, fecal pellets, coccoid-like spheroids, and authigenic quartz. Filamentous cyanobacteria Bevocastria are likely the major builder constructing the Boyun stromatolite build-ups. Stromatolites in the Boyun section likely grew in an open, oxic marine environment, differing from the Lower Triassic stromatolites that were mostly formed in relatively oxygen-poor conditions of shallow marine settings, strengthening the view that stromatolites are not necessarily indicative of harsh environments. In addition, the global dataset of cyanobacteria filament sizes through the Triassic deciphers that a pronounced increase in the diameter of filamentous cyanobacteria through the Early-Middle Triassic, followed by a decline during the Late Triassic. The developments of marine deoxygenation in the Early Triassic and Rhaetian broadly coincided with the reduction in cyanobacteria filament diameter, suggesting a possible causal link between the two. Our data also show that the diversity of cyanobacteria does not show a significant correlation relationship with any modeled estimates of CO2, indicating that their might be more complex when CO2 levels below ∼2800 ppm (10 times present atmospheric level).

Study on the Effect of Stretching on the Strength of Natural Silk Based on Different Feeding Methods.

Silk is an important biological protein fiber, which has been widely developed and used in textile and biomedical fields due to its excellent mechanical properties and good biocompatibility. Strength is an important indicator that determines the value and use of silk. Although investigations have been made on the mechanical properties of silkworm silks and their dependence relationship with the microstructures, the variation of silk strength formed in the process of silkworm spinning has not been reported. By feeding the same strain of silkworms with mulberry leaves, mulberry leaves + artificial feed, and artificial feed, silks with three filament sizes were obtained, respectively. The tensile test results showed that the strength and filament size of silk are inversely proportional. The structure and fibrosis process of different-strength silks were analyzed. The results showed that, compared with ordinary silk, the β-sheet and crystallinity content of high-strength silk is higher, indicating that its fibrosis process is more sufficient. We proposed that the stretched degree of silk protein determines its structure and properties. During the spinning process of individual silkworms, the secretion of silk protein is not stable, which will cause changes in the stretched degree. The measurement results of the intraindividual stretched degree and strength verified that the degree of stretch determines the strength of the silk. This study not only provides a deeper understanding of the properties of silk protein but also is of interest for the design and development of advanced biomimetic silk materials.

Catalytic Activity of Ni, Co, Mo Supported Anodic Aluminum Oxide Nanocomposites

Nanostructured catalysts based on porous aluminum oxide (PAO) and some 3d metals, such as: nickel, cobalt, and molybdenum, have been obtained by anodic oxidation and impregnation. The synthesis of porous aluminum oxide with a highly ordered pore structure with pore sizes of 50 nm and a thickness of 50 µm is carried out by the method of two-stage anodic oxidation. The catalysts are obtained by impregnation of 3d metals into nanosized pores of aluminum oxide. The obtained catalysts based on nickel and porous Al2O3 are studied by scanning electron microscopy (SEM-EDX). The results of SEM-EDX analysis shows that a spongy structure with filament sizes of 100 nanometers containing particles of 3d metals formed on the surface of the aluminum oxide matrix. The results are presented on the activity of nickel and heterogenic cobalt and molybdenum nanoparticles in the reaction of hydrogenation of hexene to hexane. The results show that the yield temperature of the hexane is decreased and the yield of hexane is observed at 200 °C with Ni/Al2O3 catalysts, and a similar yield of hexane mass is achieved at temperatures higher than 250 °C with Co-Mo/Al2O3 and traditional nickel catalysts on kieselguhr. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

FORMATION OF ANODIC POROUS ALUMINA IN OXALIC ACID AND ELECTRODEPOSITION OF NI.

Nanoporous anodic aluminum oxide (AAO) tubular membranes were fabricated from aluminum alloy tubes in sulfuric and oxalic acid electrolytes using a two-step anodization process. The membranes were investigated for characteristics such as pore size, interpore distance and thickness by varying applied voltage and electrolyte concentration. Morphology of the membranes was examined using light optical and scanning electron microscopy and characterized using Image software. Results showed that membranes having narrow pore size and uniform pore distribution with parallel channel arrays were obtained. The pore sizes were ranging from 10 to 100 nm and the wall thicknesses 60 μm. The catalysts are obtained by impregnation of 3d metals into nanosized pores of aluminum oxide. The obtained catalysts based on nickel and porous Al2O3 are studied by scanning microscopy (SEM-EDX). The results of SEM-EDX analysis shows that a spongy structure with filament sizes of 100 nanometers containing particles of 3d metals formed on the surface of the aluminum oxide matrix.

Effect of Structure on Response of a Three-Dimensional-Printed Photopolymer-Particulate Composite Under Intermediate Strain Rate Loading

Abstract The thermo-mechanical response of an additively manufactured photopolymer-particulate composite under conditions of macroscopic uniaxial compression without lateral confinement at overall strain rates of 400–2000 s−1 is studied. The material has a direct-ink-written unidirectional structure. Computations are performed to quantify the effects of microstructure attributes including anisotropy, defects, and filament size on localized deformation, energy dissipations, and temperature rises. To this effect, an experimentally informed Lagrangian finite element framework is used, accounting for finite-strain elastic–plastic deformation, strain-rate effect, failure initiation and propagation, post-failure internal contact and friction, heat generation due to friction and inelastic bulk deformation, and heat conduction. The analysis focuses on the material behavior under overall compression. Despite relatively low contribution to overall heating, friction is localized at fracture sites and plays an essential role in the development of local temperature spikes unknown as hotspots. The microstructural attributes are found to significantly affect the development of the hotspots, with local heating most pronounced when loading is transverse to the filaments or when the material has higher porosities, stronger inter-filament junctions, or smaller filament sizes. Samples with smaller filament sizes undergo more damage, exhibit higher frictional dissipation, and develop larger hotspots that occur primarily at failure sites.

The Power Spectra of Polarized, Dusty Filaments

Abstract We develop an analytic model for the power spectra of polarized filamentary structures as a way to study the Galactic polarization foreground to the cosmic microwave background. Our approach is akin to the cosmological halo-model framework, and reproduces the main features of the Planck 353 GHz power spectra. We model the foreground as randomly oriented, three-dimensional, spheroidal filaments, accounting for their projection onto the sky. The main tunable parameters are the distribution of filament sizes, the physical aspect ratio of filaments, and the dispersion of the filament axis around the local magnetic field direction. The abundance and properties of filaments as a function of size determine the slopes of the foreground power spectra, as we show via scaling arguments. The filament aspect ratio determines the ratio of B-mode power to E-mode power, and specifically reproduces the Planck-observed dust ratio of one-half when the short axis is roughly one-fourth the length of the long axis. Filament misalignment to the local magnetic field determines the TE cross-correlation, and to reproduce Planck measurements we need a (three-dimensional) misalignment angle with an rms dispersion of about 50°. These parameters are not sensitive to the particular filament density profile. By artificially skewing the distribution of the misalignment angle, this model can reproduce the Planck-observed (and parity-violating) TB correlation. The skewing of the misalignment angle necessary to explain TB will cause a yet-unobserved, positive EB dust correlation, a possible target for future experiments.

Comparison of Filament Sizes from Outermost to Innermost Layers of Cocoon in Fourteen Thai Polyvoltine Silkworm, Bombyx mori, Strains

Comparison of Filament Sizes from Outermost to Innermost Layers of Cocoon in Fourteen Thai Polyvoltine Silkworm, <i>Bombyx mori</i>, Strains

Deformation of flexible ferromagnetic filaments under a rotating magnetic field

Research on magnetic particles dispersed in a fluid medium, actuated by a rotating magnetic field, is becoming increasingly active for both lab-on-chip and bio-sensing applications. In this study, we experimentally investigate the behaviour of ferromagnetic filaments in a rotating field. Filaments are synthesized by linking micron-sized ferromagnetic particles with DNA strands. The experiments were conducted under different magnetic field strengths, frequencies and filament sizes, and deformation of the filaments was registered via microscope and camera. The results obtained showed that the body deformation is larger for longer filaments and higher frequencies. The angle between the filament tangent at the centre and the magnetic field direction increases linearly with frequency at the low-frequency regime. A further increase in the frequency will result in filament movement out of plane when the angle approaches 90 degrees. The experimental results were used to estimate the magnetic moment and the bending elasticity of the filament.

Effect of printing parameters in 3D concrete printing: Printing region and support structures

3D concrete printing can be used to build many complex structures. However, due to its material properties in the fresh state, it is difficult to construct overhanging structures without supports. In order to unleash the true capability of 3D concrete printing, a support structure is required to support any overhanging fresh material, which is usually removed during post-processing. This study demonstrates the feasibility of adjusting the printing parameters to print the main structure and support structure using a single type of building material. It was found that the solidity ratio, which is defined as the ratio between actual and expected filament sizes, was significantly affected by the nozzle travel speed and material volume flow rate. Furthermore, a gap distance characterisation test was carried out to find the maximum distance that the filament can cross over without a significant slump. The results were combined to determine the different printable regions for different operations. An overhang structure was printed to verify the results obtained for the different printing operations. This technique allows complex structure to be built without the need for human intervention throughout the printing process.

3D CFD study of the effect of multi-layer spacers on membrane performance under steady flow

Multi-layer feed channel spacers have shown superior mass transfer enhancement than conventional dual-layer spacers used in reverse osmosis (RO) spiral wound membrane modules. However, mass transfer indicators do not directly address the economic advantages of multi-layer spacers. To allow for a direct economic comparison of spacer designs, a simplified multi-scale techno-economic model is proposed which can provide useful cost trends. A total of 8 feed spacer geometries with different attack angles (α = 0–60°) and filament sizes (df/hch = 0.4–0.6) are first investigated using 3D-CFD. Multi-layer spacers typically increase both Sherwood number (~12%) and friction factor (~140%). The techno-economic model is then used to assess the impact of these changes on the total processing cost for RO. The latter analysis found that larger pressure drops associated with multi-layer spacers in long channels have little impact on total water processing cost for RO, with multi-layer spacers showing lower total processing costs (by 2–4%) than the dual-layer spacer for both seawater and brackish water RO. Novel spacer designs should therefore emphasise flux enhancement. The importance of including energy recovery for a more accurate economic analysis is highlighted, especially for systems with low recovery ratio.

Towards an automatic filament detector with a Faster R-CNN on MAST-U

In the present magnetically confined plasmas, the prediction of particle loading on material surfaces is a primary concern in view of the protection of plasma facing components for next step devices. Thus, an understanding of filament dynamics is needed. In this context, this work aims to develop an automatic detector for filaments arising in the MAST-U plasma. The identification of the filaments has been done starting from 2D images acquired with a fast visible camera. Therefore, it can be faced as an image object recognition problem. Currently, the object recognition is a key output of deep learning and machine learning algorithms. In this paper, a database of several thousands of images generated by a synthetic diagnostic, which reproduces the statistical properties of experimental filaments in terms of position, size and intensity has been used. The synthetic images are pre-processed by mapping them onto the toroidal midplane of the machine. Then a Faster R-CNN is customized to the problem of identifying the filaments. In particular, in order to enhance the performance of the detector, a suitable definition of the target-boxes defining the filament positions and sizes is adopted with good results.

Measuring the filamentary structure of interstellar clouds through wavelets

Context.The ubiquitous presence of filamentary structures in the interstellar medium asks for an unbiased characterization of their properties including a stability analysis.Aims.We propose a novel technique to measure the spectrum of filaments in any two-dimensional data set. By comparing the power in isotropic and anisotropic structures we can measure the relative importance of spherical and cylindrical collapse modes.Methods.Using anisotropic wavelets we can quantify and distinguish local and global anisotropies and measure the size distribution of filaments. The wavelet analysis does not require any assumptions on the alignment or shape of filaments in the maps, but directly measures their typical spatial dimensions. In a rigorous test program, we calibrate the scale dependence of the method and test the angular and spatial sensitivity. We apply the method to molecular line maps from magneto-hydrodynamic (MHD) simulations and observed column-density maps fromHerschelobservations.Results.When applying the anisotropic wavelet analysis to the MHD data, we find that the observed filament sizes depend on the combination of magnetic-field-dominated density–velocity correlations and radiative transfer effects. This can be exploited by observing tracers with different optical depth to measure the transition from a globally ordered large-scale structure to small-scale filaments with entangled field lines. The unbiased view toHerschelcolumn-density maps does not confirm a universal characteristic filament width. The map of the Polaris Flare shows an almost scale-free filamentary spectrum up to the size of the dominating filament of about 0.4 pc. For the Aquila molecular cloud the range of filament widths is limited to 0.05–0.2 pc. The filaments in Polaris show no preferential direction in contrast to the global alignment that we trace in Aquila.Conclusions.By comparing the power in isotropic and anisotropic structures we can measure the relative importance of spherical and cylindrical collapse modes and their spatial distribution.

The run-on oligomer filament enzyme mechanism of SgrAI: Part 1. Assembly kinetics of the run-on oligomer filament

Filament or run-on oligomer formation by metabolic enzymes is now recognized as a widespread phenomenon having potentially unique enzyme regulatory properties and biological roles, and its dysfunction is implicated in human diseases such as cancer, diabetes, and developmental disorders. SgrAI is a bacterial allosteric type II restriction endonuclease that binds to invading phage DNA, may protect the host DNA from off-target cleavage activity, and forms run-on oligomeric filaments with enhanced DNA-cleavage activity and altered DNA sequence specificity. However, the mechanisms of SgrAI filament growth, cooperativity in filament formation, sequestration of enzyme activity, and advantages over other filament mechanisms remain unknown. In this first of a two-part series, we developed methods and models to derive association and dissociation rate constants of DNA-bound SgrAI in run-on oligomers and addressed the specific questions of cooperativity and filament growth mechanisms. We show that the derived rate constants are consistent with the run-on oligomer sizes determined by EM analysis and are most consistent with a noncooperative growth mode of the run-on oligomer. These models and methods are extended in the accompanying article to include the full DNA-cleavage pathway and address specific questions related to the run-on oligomer mechanism including the sequestration of DNA-cleavage activity and trapping of products.