Filament Size Research Articles

Spontaneous imbibition in thin anisotropic fibrous media: Experiments and numerical modeling

In this study, we investigate the temporal and spatial evolution of wetting saturation during spontaneous imbibition in anisotropic fibrous porous media using both experimental and numerical methods. We present a novel experimental approach to systematically study spontaneous imbibition in these media, allowing for a comprehensive assessment of how microstructure influences wicking performance. The experimental method, which exhibits high reproducibility, was used to validate the numerical model. The numerical model was parameterized using only the porosity and filament diameter of the porous media in conjunction with the material properties of the imbibing fluid. The essential capillary saturation curve for the numerical model was derived using the pore morphology method. The numerical results effectively replicated the experimental results. Our experimental and numerical observations revealed a diffusive wetting front within the porous media, which progressively expanded and decelerated during the imbibition process. The results highlight the significant influence of filament size on the wetting saturation dynamics and the height of the wetting front during spontaneous imbibition.

Splitting behavior and breakup mechanism of bubbles in the split‐and‐recombine microchannel

AbstractSplit‐and‐recombine (SAR) microreactor is an advanced reactor for chemical process intensification. Bubble flow in the SAR microchannel is an important phenomenon that affects reaction efficiency, however drew little attention before. This study aims to explore the underlying mechanisms of bubble splitting, retraction, and breakup behaviors in a compact SAR microchannel. Two breakup flow patterns, unilateral flow and unilateral alternate flow were identified with symmetric or asymmetric splitting, respectively. Mechanism analysis indicates that the splitting symmetry issue is related to liquid slug size, viscous effect and novel retraction behavior of a splitting filament. The retraction is induced by the interconnection and unequal pressures between the splitting filaments. The correlation between normalized breakup time and Ca number confirms the Capillary‐pressure breakup mechanism for the splitting gas filaments. Two empirical correlations for the two breakup flow patterns were proposed, which illustrate the significant contribution of bubble retraction to the breakup degree.

3D printing and development of computational models of biodegradable meshes for pelvic organ prolapse

PurposeDevelop biodegradable meshes as a novel solution to address issues associated with using synthetic meshes for POP repair.Design/methodology/approachComputational models were created with variations in the pore geometry, pore size, filament thickness, and inclusion of filaments around specific mesh regions. Subsequently, one of the meshes was 3D printed to validate the results obtained from the simulations. Following this, a uniaxial tensile test was carried out on the vaginal tissue of a sow to compare with the simulations, to identify meshes that displayed behaviour akin to vaginal tissue. Finally, the most promising outcomes were compared with those of the uterosacral ligament and a commercially available mesh.FindingsFollowing a comprehensive analysis of the results, the mesh that most accurately replicates the behaviour of the vaginal tissue showcases a smaller pore diameter (1.50 mm), filaments in specific areas of the mesh, and variable filament thickness across the mesh. Nevertheless, upon comparing the outcomes with those of the uterosacral, the meshes do not exhibit similar behaviour to the ligament. Finally, the commercially available mesh does not represent the behaviour of both the vaginal tissue and the uterosacral ligament and in this sense may not be the best treatment option for POP repair.Originality/valueTheir biocompatibility and biomechanical properties make them a potential solution to the disadvantages of synthetic meshes. Personalized/customized meshes could be part of the future of surgical POP repair.

Traditional vs. Scientific Eri Silkworm Rearing: A Study in Bhubaneswar Zone

Sericulture holds significant importance in the tribal economy of India, with the country being the sole producer of various natural silks including mulberry, tasar, muga, oak tasar and eri silk. Eri silkworm rearing is particularly prevalent in the Bhubaneswar zone of Odisha, encompassing districts such as Khurdha, Jagatsinghpur, Nayagarh, Cuttack and Kendrapada. This study focuses on the traditional eri culture methods in the region, highlighting indigenous rearing techniques, food plant selection, larvae management etc. Observations revealed that traditional practices were consistent across the Bhubaneswar region, emphasizing the need for adopting scientific methods. Implementing tray/platform rearing, precise feeding techniques, strategic food plant selection during different larval stages, well-designed rearing rooms and advanced spinning methods can optimize space usage, ensure disease-free larvae, promote uniform cocoon production, increase the effective rate of rearing and silk production. The disparities in shell percentage between cocoons at the farmer level and the farm level in the Bhubaneswar zone are indicative of varying practices and care in sericulture. Farmer-level cocoons exhibit a lower shell ratio ranging from 9.17% to 9.82%, implying inadequate care and nutrition provided to growing silkworms. This discrepancy suggests that these farmers might face challenges in maintaining suitable conditions such as proper temperature, humidity and nutrition, leading to inferior cocoon quality. Conversely, at the farm level, the shell ratio ranges from 10.14% to 10.71%, indicating that farmers in this category are comparatively more adept at silk rearing practices. They provide better nutrition, suitable temperature, humidity and other necessary facilities, resulting in higher-quality cocoons. The superior environment and care provided at the farm level are reflected in the Effective Rate of Rearing (ERR%) consistently above 40%, reaching a maximum of 50.85%. This signifies that farm-level cocoons have better attributes such as cocoon weight, shell thickness and filament size compared to those reared by individual farmers, where ERR% ranged from 31% to 42%. The integration of modern techniques not only enhances production potential but also creates employment opportunities for rural youth. This approach fosters better income generation, surpassing the limitations of traditional methods and paving the way for a thriving sericulture industry.

Solar Filament Detection Based on an Improved Deep Learning Model

Solar filaments are good tracers of space weather and magnetic flux ropes in the corona. Identifying and detecting filaments helps to forecast space weather and explore the solar magnetic field. Many automatic detection methods have been proposed to process the large number of observed images. Current methods face issues of unreliable dataset annotations and poor anti-interference capability. First, to address the issue of unreliable dataset annotations, we built a solar filament dataset using a manual annotation method. Second, we introduced Transformer into Convolutional Neural Networks. Transformer, with the ability to extract more global features, can help counter interference. In addition, there is large disparity in the size of solar filaments. Therefore, a multi-scale residual block is designed to extract features across various scales. Deformable large kernel attention and a res path are used to better integrate encoder and decoder information. Results show that this method outperforms the existing solar filament detection methods (improved U-Net and improved V-Net), achieving an F1 score of 91.19%. In particular, our results show lower interference by sunspots and background noise than existing methods. The ability to counter interference is improved.

Optimization of Bilayer Resistive Random Access Memory Based on Ti/HfO2/ZrO2/Pt.

In this paper, the electrothermal coupling model of metal oxide resistive random access memory (RRAM) is analyzed by using a 2D axisymmetrical structure in COMSOL Multiphysics simulation software. The RRAM structure is a Ti/HfO2/ZrO2/Pt bilayer structure, and the SET and RESET processes of Ti/HfO2/ZrO2/Pt are verified and analyzed. It is found that the width and thickness of CF1 (the conductive filament of the HfO2 layer), CF2 (the conductive filament of the ZrO2 layer), and resistive dielectric layers affect the electrical performance of the device. Under the condition of the width ratio of conductive filament to transition layer (6:14) and the thickness ratio of HfO2 to ZrO2 (7.5:7.5), Ti/HfO2/ZrO2/Pt has stable high and low resistance states. On this basis, the comparison of three commonly used RRAM metal top electrode materials (Ti, Pt, and Al) shows that the resistance switching ratio of the Ti electrode is the highest at about 11.67. Finally, combining the optimal conductive filament size and the optimal top electrode material, the I-V hysteresis loop was obtained, and the switching ratio Roff/Ron = 10.46 was calculated. Therefore, in this paper, a perfect RRAM model is established, the resistance mechanism is explained and analyzed, and the optimal geometrical size and electrode material for the hysteresis characteristics of the Ti/HfO2/ZrO2/Pt structure are found.

Filamentary velocity scaling validation and spin dynamics in the DIII-D tokamak

Measured filament velocities in the DIII-D tokamak are compared against theoretical scalings, finding that the latter often represents an upper limit on experimental velocity distributions with most filaments possessing lower velocity. Filament spin from internal E × B drift is experimentally demonstrated to alter filament radial velocity. A critical spin velocity, where filament radial velocity peaks, is observed and corresponds to approximately 5 km/s. This transition is corroborated using a less direct measure of filament spin in the form of a temperature ratio. These techniques are combined to find that the critical spin velocity closely aligns with transport times along and across filaments becoming comparable. The normalized filament size distribution is consistent with the most stable size as dictated by Kelvin–Helmholtz and curvature-driven instabilities. Overall, the findings suggest filament stability and spin alter filamentary transport that may threaten the integrity of first walls in fusion devices.

Enhancing 3D printability of polyhydroxybutyrate (PHB) and poly(3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV) based blends through melt extrusion based-3D printing

Polyhydroxybutyrate (PHB) and poly (3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV) possess favorable biological properties such as biocompatibility and biodegradability, making them suitable for various applications. However, their utility is limited by a narrow processing window due to low thermal stability and challenges in manipulating filament size during extrusion, attributed to poor melt strength. These issues result in irregularities such as discontinuous flow and incomplete deposition of melted PHB, significantly affecting 3D printing outcomes. To address these concerns, this study explores blending PHB and PHBV with poly (lactic acid) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT) to enhance its processability and printability. Thermal analysis of all blends revealed three distinct degradation steps occurring at approximately 300, 360, and 400ºC, corresponding to PHB or PHBV, PLA, and PBAT, respectively. Moreover, the melting temperatures of PHB, PHBV, PLA, and PBAT were measured around 176, 173, 152, and 121ºC, respectively. It was observed that the polymer blends exhibited lower crystallization temperature and degree of crystallinity compared to PHB or PHBV. Assessing their 3D printability, neat PHB and PHBV filaments experienced fusion issues, poor flow during extrudate deposition, and significant warping, leading to 3D printing failures. In contrast, the blends displayed enhanced flowability and successfully produced high-quality specimens. Scanning electron microscope (SEM) analysis highlighted a phase separation morphology in the blends, showcasing uniform dispersion of PLA and PBAT within the PHB matrix.

A new species of Mesocapparis (Capparaceae) from the Brazilian Cerrado

Mesocapparis minutiflora, a new species for the Cerrado, is described and compared with related species. The taxon is described from the state of Tocantins and Piauí, with only five known collections. It is distinguished from other species mainly by the different shapes of leaf base, petiolar insertion, and the shorter size of petals, gynophore, and filaments. The conservation status of the new species is discussed, and information is provided on its flowering period and geographic distribution.

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.

Responding to light signals: a comprehensive update on photomorphogenesis in cyanobacteria.

Cyanobacteria are ancestors of chloroplast and perform oxygen-evolving photosynthesis similar to higher plants and algae. However, an obligatory requirement of photons for their growth results in the exposure of cyanobacteria to varying light conditions. Therefore, the light environment could act as a signal to drive the developmental processes, in addition to photosynthesis, in cyanobacteria. These Gram-negative prokaryotes exhibit characteristic light-dependent developmental processes that maximize their fitness and resource utilization. The development occurring in response to radiance (photomorphogenesis) involves fine-tuning cellular physiology, morphology and metabolism. The best-studied example of cyanobacterial photomorphogenesis is chromatic acclimation (CA), which allows a selected number of cyanobacteria to tailor their light-harvesting antenna called phycobilisome (PBS). The tailoring of PBS under existing wavelengths and abundance of light gives an advantage to cyanobacteria over another photoautotroph. In this work, we will provide a comprehensive update on light-sensing, molecular signaling and signal cascades found in cyanobacteria. We also include recent developments made in other aspects of CA, such as mechanistic insights into changes in the size and shape of cells, filaments and carboxysomes.

Potential 3D filament of Janeng (Dioscorea hispida Dennst) starch: Preparation and characterization

The preparation and characterization of filaments from janeng have been studied. The janeng filament (PCl-JS) process starts with the preparation and gelatinization of janeng starch, and then the resulting starch gelatinization, which is usually called thermoplastically processable starch (TPS) is carried out by filament processing by mixing PCl-g-GMA and JS at a temperature of 170 °C and 80 rpm for 15 min. The prepared filaments were analyzed. SEM studies show that the fracture surface of PCl-JS0 filaments provides a uniform fiber dispersion, in contrast to the morphology showing large and interconnected starch domains as the starch concentration increases from 1% to 9%. The intensity of hydrogen bonds observed in the spectrum via FTIR increased in band as the concentration of JS increased. XRD analysis observed that the crystallinity and crystal size of filaments without starch were higher than those of other PCl filaments that had undergone modification with starch. Mechanical analysis showed that starch did not have a negative effect on the tensile strength of the filaments, indicating good compatibility between JS and the PCl matrix. When the additional concentration of JS increased to 9%, the strength of PCl-JS filaments increased to 37 MPa, which was caused by the higher crystallinity induced by starch. The glass temperature of the filament sample was observed using DSC, which showed that PCl without JS occurred at 48.2 °C and shifted (+2 °C) towards 49.4 °C when JS was added. For all DSC curves, the exothermic peak was observed around 56–59 °C. The melt flow behavior of PCl-JS filaments decrease with increasing starch content.

Laser-induced sonar: A promising approach for improved underwater acoustic sensing

This study presents the characteristics of acoustic pressure impulses generated by nanosecond laser-induced filamentation (ns-LIF) of water, focusing on the spatial, temporal, and spectral domains. In the time domain, the peak-to-peak (Pk-Pk) overpressures increase with higher incident optical energy while the arrival time remains constant. Notably, linearly polarized pulses exhibit higher Pk-Pk overpressures than circularly polarized pulses. Acoustic measurements of ns-LIF in water demonstrate a linear correlation between filament size and incident laser energy due to multiple plasma sources along the optical beam propagation. Alongside the temporal information, the spectrogram visualizes broad-spectrum underwater acoustic pressure impulses ranging from 10 to 800 kHz, perpendicular to the optical beam propagation. The low-frequency instantaneous underwater acoustic signals generated by ns-LIF is ∼90 kHz, offering advantages such as extended propagation distances and reduced attenuation in water. In addition to the experimental investigation, finite element analysis is employed to visualize the propagation and interaction of underwater acoustic signals across various interfaces. This integrated approach provides valuable insights into the behavior and characteristics of underwater signals. Eventually, our findings demonstrate the successful development of remote laser-induced sonar technology.

Microtube embedded hydrogel bioprinting for vascularization of tissue-engineered scaffolds.

Vascular tissue engineering has been considered promising as one of the alternatives for viable artificial tissues and organs. Macro- and microscale hollow tubes fabricated with various techniques have been widely studied to mimic blood vessels. To date, the fabrication of biomimetic capillary vessels with sizes ranging from 1 to 10 µm is still challenging. In this paper, core-sheath microtubes were electrospun to mimic capillary vessels and were embedded in carboxymethyl cellulose/sodium alginate hydrogel for bioprinting. The results showed improved printing fidelity and promoted cell attachment. The tube concentration and tube length both had significant influences on filament size and merging area. Printed groups with higher microtube concentration showed higher microtube density, with filament/nozzle size ratio, and printed/designed grid area ratio closer to 100%. In the in vitro experiments, microtubes were not only compatible with human umbilical vein endothelial cells but also provided microtopographical cues to promote cell proliferation and morphogenesis in three-dimensional space. In summary, the microtubes fabricated by our groups have the potential for the bioprinting of vascularized soft tissue scaffolds.

Sarcomeric network analysis of ex vivo cultivated human atrial appendage tissue using super-resolution microscopy

Investigating native human cardiac tissue with preserved 3D macro- and microarchitecture is fundamental for clinical and basic research. Unfortunately, the low accessibility of the human myocardium continues to limit scientific progress. To overcome this issue, utilizing atrial appendages of the human heart may become highly beneficial. Atrial appendages are often removed during open-heart surgery and can be preserved ex vivo as living tissue with varying durability depending on the culture method. In this study, we prepared living thin myocardial slices from left atrial appendages that were cultured using an air-liquid interface system for overall 10 days. Metabolic activity of the cultured slices was assessed using a conventional methyl thiazolyl tetrazolium (MTT) assay. To monitor the structural integrity of cardiomyocytes within the tissue, we implemented our recently described super-resolution microscopy approach that allows both qualitative and quantitative in-depth evaluation of sarcomere network based on parameters such as overall sarcomere content, filament size and orientation. Additionally, expression of mRNAs coding for key structural and functional proteins was analyzed by real-time reverse transcription polymerase chain reaction (qRT-PCR). Our findings demonstrate highly significant disassembly of contractile apparatus represented by degradation of alpha -actinin filaments detected after three days in culture, while metabolic activity was constantly rising and remained high for up to seven days. However, gene expression of crucial cardiac markers strongly decreased after the first day in culture indicating an early destructive response to ex vivo conditions. Therefore, we suggest static cultivation of living myocardial slices derived from left atrial appendage and prepared according to our protocol only for short-termed experiments (e.g. medicinal drug testing), while introduction of electro-mechanical stimulation protocols may offer the possibility for long-term integrity of such constructs.

3D printing of poly(ethylene oxide) or electrospun polystyrene microtube embedded sodium alginate and carboxymethyl cellulose hydrogel

Tissue engineering has gained numerous attentions in recent years and was considered the one of the alternative treatments for tissue regeneration and organ repair. Nowadays, many natural and synthetic materials were selected as biomaterial to fabricate artificial tissue scaffolds. However, poor mechanical strength and biocompatibility are still challenging. In this study, polystyrene (PS) electrospun microtubes and poly(ethylene oxide) (PEO) were added into carboxymethyl cellulose (CMC)/sodium alginate (SA) composite hydrogel for printing. Viscosity, filament size, filament collapse, swelling, tensile, and compressive tests were applied to investigate their different properties. The results indicated that the addition of PS microtubes in SA hydrogel significantly increased filament size. Although the addition of PEO and microtubes had less influences on printability, the group of CMC/SA/PEO presented the highest collapse area factor. The tensile test showed that CMC/SA/PS had highest tensile strength and elongation. This research verified the feasibility of adding microtubes into hydrogel as potential soft tissue scaffolds material.

Pengaruh Tingkat Infill Filament dan Printing Speed Terhadap Sifat Mekanis dan Struktur Hasil 3D Printing

3D printing is one of the uses of additive manufacturing in the industrial and academic fields. Along with 3D printing, many printing results have changed from the initial size. This causes the product to be unsuitable and can affect the level of use of the 3D printing results. This study aimed to test the results of 3D printing with different print speed times to find the degree of difference in the filaments making up the 3D printing results. The significant difference in volume (infill) in the 3D printing result will affect the final 3D printing result. After testing, the result is that the greater the printing speed, the higher the filament size and surface roughness level. The mechanical properties of the 3D Printing results have increased in yield strength, maximum load, and elongation. The highest value obtained from the average size of the filament is 600.13 µm at 50% infill with a print speed of 50%. The highest yield strength, maximum load, and elongation values were obtained at 100% infill with a print speed of 50% of 2,534 N/mm2, 8,136%, 96,059 N.

Magnetization AC losses of MgB2 wires with thin filaments and resistive sheath

Magnetization AC losses of fine-filamentary MgB2 wires with resistive CuNi sheaths were measured. The effects of varying the number of filaments (114–342, corresponding to effective filament diameters of 14–20 μm), twist pitch (10–30 mm) and outer sheath material on the total AC loss were studied. For a better understanding of individual loss contributions, the effects of varying applied temperature, magnetic field, and frequencies were examined. It is found that hysteresis loss per volume decreases with the reduced filament size and that coupling current losses play a dominant role. The effect of decoupling by twisting was clearly observed for the smallest twist pitches. Considering the possible degradation of transport currents by twisting, AC losses were also normalized by the critical currents of the same wires. While twisting to short pitch decreases losses significantly, it apparently does not reduce the transport current. Consequently, the fine-filamentary MgB2 wires with resistive CuNi sheath examined in this paper are excellent candidates for future low loss applications. Unlike ReBCO tapes, round MgB2 wires enable easy single strand twisting, and the braiding or cabling, of wires into a variety of specific shapes and diameters.

Characterization of Mechanical and Cellular Effects of Rhythmic Vertical Vibrations on Adherent Cell Cultures.

This paper presents an innovative experimental setup that employs the principles of audio technology to subject adherent cells to rhythmic vertical vibrations. We employ a novel approach that combines three-axis acceleration measurements and particle tracking velocimetry to evaluate the setup's performance. This allows us to estimate crucial parameters such as root mean square acceleration, fluid flow patterns, and shear stress generated within the cell culture wells when subjected to various vibration types. The experimental conditions consisted of four vibrational modes: No Vibration, Continuous Vibration, Regular Pulse, and Variable Pulse. To evaluate the effects on cells, we utilized fluorescence microscopy and a customized feature extraction algorithm to analyze the F-actin filament structures. Our findings indicate a consistent trend across all vibrated cell cultures, revealing a reduction in size and altered orientation (2D angle) of the filaments. Furthermore, we observed cell accumulations in the G1 cell cycle phase in cells treated with Continuous Vibration and Regular Pulse. Our results demonstrate a negative correlation between the magnitude of mechanical stimuli and the size of F-actin filaments, as well as a positive correlation with the accumulations of cells in the G1 phase of the cell cycle. By unraveling these analyses, this study paves the way for future investigations and provides a compelling framework for comprehending the intricate cellular responses to rhythmic mechanical stimulation.

3D-reconstructions of zygospores in Zygnema vaginatum (Charophyta) reveal details of cell wall formation, suggesting adaptations to extreme habitats.

The streptophyte green algal class Zygnematophyceae is the immediate sister lineage to land plants. Their special form of sexual reproduction via conjugation might have played a key role during terrestrialization. Thus, studying Zygnematophyceae and conjugation is crucial for understanding the conquest of land. Moreover, sexual reproduction features are important for species determination. We present a phylogenetic analysis of a field-sampled Zygnema strain and analyze its conjugation process and zygospore morphology, both at the micro- and nanoscale, including 3D-reconstructions of the zygospore architecture. Vegetative filament size (26.18 ± 1.07 μm) and reproductive features allowed morphological determination of Zygnema vaginatum, which was combined with molecular analyses based on rbcL sequencing. Transmission electron microscopy (TEM) depicted a thin cell wall in young zygospores, while mature cells exhibited a tripartite wall, including a massive and sculptured mesospore. During development, cytological reorganizations were visualized by focused ion beam scanning electron microscopy (FIB-SEM). Pyrenoids were reorganized, and the gyroid cubic central thylakoid membranes, as well as the surrounding starch granules, degraded (starch granule volume: 3.58 ± 2.35 μm3 in young cells; 0.68 ± 0.74 μm3 at an intermediate stage of zygospore maturation). Additionally, lipid droplets (LDs) changed drastically in shape and abundance during zygospore maturation (LD/cell volume: 11.77% in young cells; 8.79% in intermediate cells, 19.45% in old cells). In summary, we provide the first TEM images and 3D-reconstructions of Zygnema zygospores, giving insights into the physiological processes involved in their maturation. These observations help to understand mechanisms that facilitated the transition from water to land in Zygnematophyceae.