Diameter Size Research Articles

Evaluation of types and concentration of bile salts impact on physical properties of nisoldipine-loaded bilosomes

Background: Bilosomes are lipid vesicles that exhibit flexibility and deformability. They consist of phospholipids and amphiphilic bile salts. Compared to the normal vesicular systems such as liposomes and niosomes, bilosomes provide several notable advantages, including simplified manufacturing, cost-effectiveness, and enhanced stability. Aim: The main objective of the present work was to evaluate the effect of different bile salts on the physical properties that include entrapment efficiency, vesicle size, and polydispersity index(PDI). In addition, in vitro drug release for nisoldipine (NSD) loaded bilosomes was evaluated. Methods: Nisoldipine-loaded bilosomes were made using a thin film hydration technique. Cholesterol along with surfactant (span 60) was employed, and the formulation also contained several different bile salts, including sodium deoxycholate (SDC), sodium glycocholate (SGC), and sodium taurocholate (STC). Results: The developed NSD bilosomes exhibited an entrapment efficiency ranging from 44.2 ± 0.3 to 82.36 ± 0.80% and a vesicle size diameter in the nanometric dimensions (166 ± 1.83 to 237.8 ± 3.3 nm). An in-vitro release study revealed that formulas prepared with SDC bile salts showed higher drug release than SGC and STC formulas. Increasing the bile salt amount from 5 mg to 10 mg increases entrapment efficiency with increasing vesicle size. Further increase in bile salt led to decreased entrapment efficiency with increased vesicle size. SDC gives the best result in terms of entrapment efficiency and acceptable size. STC provides the largest particle size due to its high molecular weight compared to SGC and SDC. Conclusion: The SDC bile salt component is better suited for manufacturing NSD bilosomes. This is because this component yields the best results regarding high entrapment efficiency, nano size, and prolonged drug release.

Forecasting Sauter mean droplet size and examining the range of droplet sizes in a Tenova liquid–liquid extraction column

A new type of Tenova pulsed extraction column was introduced in 2017. It is the newest generation of pulsed columns. Due to the internal equipment of this column and the lack of moving parts and the simplicity and speed of repairs and maintenance, it has been the focus of researchers in recent years. No correlations for predicting the mean drop size and drop size distribution of the Tenova column have been reported. The Sauter mean drop diameter and drop size distribution are investigated for a Tenova pulsed column with a diameter and an active height of 7.4 and 73 cm, respectively. Three standard chemical systems of isobutyl acetate-water, isobutanol-water, and toluene-water have been used. The effects of pulse intensity, dispersed and continuous phase flow rates have been taken into account. In each experiment, 200–300 drops have been analyzed in a total of 10,000 drops. The investigation covered a spectrum of physical properties, notably surface tension (within a range of 1.75–36 mN/m). Operating conditions including pulse intensity (in the range of 0.2–2 cm/s) and the flow rate of continuous and dispersed phases (in the range of 8–30 L/h) have been investigated. Methods based on artificial intelligence (AI) such as multilayer perceptron neural networks and gene expression programming were combined with a dimensional analysis approach to provide a new approach to estimating the mean drop diameter (d32). Experimental results have been compared with the equations found by other researchers in similar columns. The variation of drop size distribution has also been experimentally obtained.Methods based on artificial intelligence (AI) such as multilayer perceptron neural networks and gene expression programming were combined with a dimensional analysis approach to provide a new approach to estimating the mean drop diameter (d32). Experimental results have been compared with the equations found by other researchers in similar columns. The variation of drop size distribution has also been experimentally obtained.

An Innovative Approach to Alleviate Zinc Oxide Nanoparticle Stress on Wheat through Nanobubble Irrigation.

The extensive utilization of zinc oxide nanoparticles in consumer products and the industry has led to their substantial entry into the soil through air and surface runoff transportation, which causes ecotoxicity in agro-ecosystems and detrimental effects on crop production. Nanobubbles (diameter size < 1 µm) have many advantages, such as a high surface area, rapid mass transfer, and long retention time. In this study, wheat seedlings were irrigated with a 500 mg L-1 zinc oxide nanoparticle solution delivered in the form of nanobubble watering (nanobubble-ZnO-NPs). We found that nanobubble watering improved the growth and nutrient status of wheat exposed to zinc oxide nanoparticles, as evidenced by increased total foliar nitrogen and phosphorus, along with enhanced leaf dry mass per area. This effect can be attributed to nanobubbles disassembling zinc oxide aggregates formed due to soil organic carbon, thereby mitigating nutrient absorption limitations in plants. Furthermore, nanobubbles improved the capability of soil oxygen input, leading to increased root activity and glycolysis efficiency in wheat roots. This work provides valuable insights into the influence of nanobubble watering on soil quality and crop production and offers an innovative approach for agricultural irrigation that enhances the effectiveness and efficiency of water application.

A Review on Methods of Cenosphere Separation from Fly Ash

Cenospheres are valuable material contained inside the fly ash. Its low weight, low density, and high strength made it very versatile and can be used in various fields. The way of separating the cenosphere from the fly ash consists of two categories, wet and dry separation. For wet separation, it involves submerging the fly ash inside a mixture made either by pure acetone, pure water, or a mixture of water and acetone with different mixing ratios before stirring the mixture. The cenospheres, floating on top of the mix due to low density, can be collected and dried. The dry separation technique involves putting the fly ash into a cyclone separator at a constant velocity. The fly ash will then move into the bottom of the cyclone. Particles can also be separated by diameter sizes by sieving. By manipulating various parameters, cenosphere yield may differ. This paper is written to help gain more understanding on cenosphere properties and its separation method.

Characterization of residual debris on packaged hip arthroplasty stems demonstrates the dominance of less than 10 μm sized particulate: Updated USP788 guidelines for orthopedic implants.

Past evaluation of particle contamination on packaged implants has typically been conducted using US Pharmacopeia (USP) 788, a 1970s pharmaceutical guideline created to evaluate contaminant particles in injectable fluids and syringes. Our objective was to reestablish relevant acceptance criteria for residual orthopedic and other implant debris, including smaller particles (i.e., <10 μm in diameter). Packaged total hip arthroplasty (THA) titanium (Ti6Al4V)-alloy femoral stems were used (hydroxyapatite [HA]-coated and non-coated stems). Short-term ultrasonication and longer-term 24-hour soak/agitation methods were used to elute surface-bound contaminant particles, and released particles were analyzed via scanning electron microscopy, energy-dispersive x-ray analysis, image analysis, and particle characterization. For HA-coated THA-stems, >99% of eluted particles were calcium phosphate. For plain non-coated THA-stems, >99% of eluted particles were titanium-alloy-based. The number-based median size of particles in both groups was approximately 1.5 μm in diameter despite being composed of different materials. The total volume of particulate removed from HA-coated stems was 0.037 mm3 (671 × 103 particles total), which was approximately >50-fold more volume than that on plain non-coated stems at 0.0006 mm3 (89 × 103 particles total). Only non-coated THA stems passed reestablished USP788 acceptance criteria, compared by using equivalent total volumes of contaminant particulate within new and legacy guideline ranges of >10 and >25 μm ECD, that is, <1.0 × 107 particles for <1 μm diameter in size, <600,000 for <1-10 μm, <6000 for 10-25 μm and <600 for >25 μm. These results fill a knowledge gap on how much residual debris can be expected to exist on packaged implants and can be used as a basis for updating acceptance criteria (i.e., termed USP788-Implant [USP788-I]). Residual implant particulate assessment is critical given the increasing implant complexity and new manufacturing techniques (e.g., additive manufacturing).

The presence of micropapillary and/or solid subtypes is an independent prognostic factor for patients undergoing curative resection for stage I lung adenocarcinoma with ground-glass opacity.

Non-predominant or even minimal micropapillary and/or solid (MP/S) subtypes have been reported to exert an unfavorable prognostic influence on surgically resected lung adenocarcinoma (ADC). Currently, there is a lack of evidence to demonstrate that high-grade pathological subtypes, including MP/S components, impact the prognosis of patients with surgically resected lung ADCs with ground-glass opacity (GGO). In this investigation, we explored the prognostic implications of minimal MP/S components in lung ADCs with GGO. A retrospective cohort study was conducted on 1,004 consecutive patients undergoing curative resection for pathologic stage (p-stage) I lung ADCs featuring GGO on computed tomography (CT) scans between January 2014 and December 2016. Tumors were categorized into MP/S positive (MP/S+) group and MP/S negative (MP/S-) group. MP/S+ tumors were defined when MP/S subtypes constituted ≥1% of the entire tumor. The prognostic impact of MP/S subtypes was evaluated using Kaplan-Meier analysis, Cox proportional hazard model and restricted cubic spine (RCS) model. A total of 86 (8.6%) cases with MP/S+ tumors and 918 (91.4%) cases with MP/S- tumors were identified. The solid component tumor diameter and pathological invasive tumor size of MP/S+ tumors were both significantly larger than that of MP/S- tumors (13.0 vs. 4.0 mm, P<0.001, and 18.0 vs. 10.0 mm, P<0.001, respectively). After a median follow-up of 7.3 years, the presence of MP/S components was significantly associated with decreased RFS (5-year RFS, MP/S+ 88.3% vs. MP/S- 97.4%; P<0.001; HR =1.02). The presence of a histologic lepidic (Lep) component demonstrated a prognostic advantage in both MP/S- (5-year RFS, MP/S-Lep+ 98.0% vs. MP/S-Lep- 95.3%; P=0.01; HR =0.89) and MP/S+ subgroups (5-year RFS, MP/S+Lep+ 93.4% vs. MP/S+Lep- 83.2%; P=0.10; HR =0.84). MP/S+ components ≥5% were the only tumor-related factor that independently affected RFS [hazard ratio (HR) =1.77; 95% confidence interval (CI): 1.07-2.94] according to multivariate analysis. There was a progressively negative impact of the proportion of MP/S subtypes on RFS as illustrated by RCS model. The presence of MP/S patterns in stage I GGO-featured lung ADCs exhibit significant prognostic value and may have implications for tailored postoperative treatment and surveillance strategies, especially when the proportion exceeds 5% of the entire tumor.

In vitro α-amylase/α-glucosidase, cytotoxicity and radical scavenging potential of Hypoxishemerocallidea synthesized magnesium oxide nanoparticles

The prevalence of diabetes has continued to increase over the past decade. Medicinal extract-synthesized nanoformulations incorporating trace elements found in the body have emerged as alternative therapeutic technology for the treatment of diabetes. In this study, magnesium oxide (MgO) nanoparticles were prepared using Hypoxishemerocallidea (HH) and investigated for their cytotoxicity, antioxidant, and antidiabetic potentials. MgO NPs were characterized by transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, and zeta-potential techniques. TEM analysis confirmed the 2D nanosheet-like morphology of the nanoparticles with particle size (diameter; 300 nm and length of about 1 µm) while the FTIR spectra showed functional groups correlating to the bioactive compounds of HH in the MgO NPs. Moderate antioxidant activity of MgO NPs was observed against DPPH (IC50 = 57.35 ± 0.28 µg/mL) and ABTS (IC50 = 52.08 ± 0.24 µg/mL). The nanoparticles were shown to be less toxic to normal embryonic (HEK293) and human liver (HEPG2) cell lines, with IC50 of 48.63 ± 0.73 and 32.39 ± 0.95 µg/mL, respectively compared to a known cytotoxic drug, doxorubicin which exhibited IC50 of 2.70 ± 0.32 and 8.62 ± 0.57 µg/mL respectively. Besides, the anti-hyperglycemic potential of the MgO NPs as demonstrated by α-amylase and α-glucosidase activities were significantly high with IC50 values of 33.03 ± 1.43 and 52.38 ± 3.06 µg/mL, respectively. These results were compared with an FDA-approved antidiabetic reference standard Acarbose, which exhibited IC50 values of 24.54 ± 1.55 and 6.54 ± 0.27 µg/mL. The results indicated that the HH bioinspired MgO NPs are capable of inhibiting meditators of diabetes and oxidative stress. This study further suggests that the MgO NPs synthesized using HH could be a good candidate for the management of diabetes and other inflammatory diseases due to their strong enzyme inhibition, efficient antioxidant properties, and biocompatibility.

Neurodevelopmental Outcome at 3 Years of Age in Very Low Birth Weight Infants According to Brain Development and Lesions.

During the last decades, severe brain lesions affecting very low birth weight (<1500 gr, VLBW) infants were gradually substituted by milder lesions with debatable prognoses. The objective of this study is to define type, frequency and 3 years of neurodevelopmental outcome of prematurity-related brain lesions in a modern cohort of VLBW infants. VLBW infants admitted to our NICU in 5 years period with brain MRI at term-equivalent age were included. MRI scans were reviewed to identify and grade white matter lesions (WML), intraventricular hemorrhage (IVH), and cerebellar hemorrhage (CBH). Linear measurements of brain size, biparietal width (BPW) and trans-cerebellar diameter (TCD) were carried out. Total maturation score (TMS) was calculated. Developmental Coefficients (DQ) on Griffiths Scale at 3 years of age were compared between patients with different types and grades of lesions and patients without lesions; possible correlations between linear brain measurements, brain maturation and outcome were explored. Study included 407 patients. Of them, 187 (46%) had at least one brain lesion on MRI, while 37 (9%) had severe lesions. The most frequent lesion was IVH (28%), followed by WML (21%) and CBH (17%). Mild and severe IVH, moderate and severe WML and all grades of CBH were related to worst outcome at 3 years. In patients without lesions, small BPW and small TCD were associated with worse outcomes. No correlations were observed between TMS and outcome. We have observed that even mild brain lesions have a negative influence on neurological outcome at 3 years of age.

Cytotoxicity Assay of Biosynthesized Gold Nanoparticles for Synephrine Extracted from Citrus Sinesins Peels

In this study synephrine extracted from C. sinesins peels. Detected by TLC, HPLC and biosynthesized gold nanoparticles from it, then characterization of synthesize of gold nanoparticles (AuNps) by UV-visible spectroscopy Fourier Transform Infrared (FTIR), which confirm presence of AuNps in diameter size range to (9-31) nm and determined their toxicity assay on lymphoid human cell in 24, 48 and 72 hours. The finding obtained from applying gold nanoparticles at different concentrations for 24, 48, and 72 hours showed that’s the least cytotoxicity value was in 2.351 in 10 mg/ml for Citrus sinensis extract in 24 hours. which gave indicate that synephrine extracted have not toxic effect inhibition rate of this maximum 5.511 in AuNp biosynthesized in 20 mg/ml concentration in 72 hours.

Penicillium oxalicum-mediated the green synthesis of silica nanoparticles: characterization and environmental applications

AbstractIn terms of biocompatibility, environmental friendliness, scalability, and cost-effectiveness, green nanoparticle (NP) synthesis is a modern area of nanotechnology that performs better than physical and chemical methods. The utilization of endophytic Penicillium oxalicum for the biogenesis of silica nanoparticles is the goal of the current work. The structural and optical properties of the fungal produced silica nanoparticles were investigated utilizing transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), x ray diffraction (XRD) and dynamic light scattering (DLS). All of the investigated parameters and their interactions were found to have a significant effect on the crystallite size, according to the results. The average diameter size of the biosynthesized SiO2-NPs was ranged between 20 -50 nm. The size of the biosynthesized SiO2-NPs was 28.7 nm, and their crystalline nature was confirmed by XRD, according to characterization results. A surface plasmon resonance spectrum of silica nanoparticles was obtained at 280 nm. Under UV light, Ribazol black b and Crystal violet dyes were photocatalytically degraded utilizing biosynthesized SiO2 nanoparticles. The highest decolorization percentage of Crystal violet and Ribazol black b was 94.1% ± 1.2% and 85.1% ± 0.93%, respectively after 90 and 120 min, for both crystal violet and Ribazol black b of incubation at 50.0 mg mL─1 of SiO2 nanoparticles. Furthermore, SiO2-NPs were successfully used more than once for biodegradation and that was regarded as its efficacy. Silica nanoparticles were used to remove Co, Pb, Cd, and Zn with percentages of 99.9% ± 1.2%, 99.9% ± 1.3%, 99.9% ± 1.3%, and 99.4% ± 1.4%, respectively. The phytotoxicity test was investigated by using Zea mays L seed which the root length increases to (28 ± 0.35) and (21 ± 0.51) cm, respectively when subjected tothe treated CV and Ribazole black b effluent... In conclusion, endophytic Penicillium oxalicum was used to successfully biosynthesize SiO2-NPs, which showed, phytotoxicity, heavy metal bioremediation, and photocatalytic activity against CV and Ribazol black b dye.

The potential application of cellulose acetate membrane for CO2 adsorbent

ABSTRACT Numerous countries have deployed significant efforts to reduce the amount of CO2 released into the atmosphere. Carbon capture and storage is widely regarded as a mitigation technique that can significantly reduce CO2 emissions. A crucial stage in carbon capture and storage is CO2 adsorption using a membrane. Cellulose acetate has demonstrated excellent properties as a membrane material. In this study, we examined the potential of cellulose acetate membrane (CAM) for CO2 gas capture. Two forms of CAM were developed for this study, with and without the addition of glycerol. Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), and CO2 adsorption analyses were used to characterise CAM in numerous ways. The analysis revealed that the addition of glycerol improved the gas adsorption properties of the material. The incorporation of glycerol into the cellulose acetate matrix resulted in an observed augmentation in both the diameter and pore size. The adsorption properties of CO2 are significantly influenced by the microscopic structure of the cellulose acetate membrane. The CAM can be viewed as a possible material for CO2 adsorbers.

Height increment patterns in Pinus pinaster seedlings emerging in naturally regenerated gaps

Abstract The group selection cutting system provides a promising technique for transforming monospecific even-aged stands into uneven-aged, mixed stands. However, this system has scarcely been used to regenerate Mediterranean shade-intolerant species. In this study, we analyze the height increment patterns of Pinus pinaster seedlings emerging in naturally regenerated gaps. P. pinaster is a shade-intolerant pine species distributed throughout the Mediterranean basin. An experimental trial was established in a 50-year-old P. pinaster (maritime pine) plantation located in the mountains of central Spain. Gaps of two different sizes (diameter equal to 1.5 and 2.5 times the dominant height of the stand, 26 and 44 m, respectively) were opened during winter 2017–18. A total of 531 subplots with a 1-m radius were installed in spring 2018, distributed within the gaps as well as in control plots adjacent to the gaps. Seedlings were tagged individually and variables including height, along with other ecological variables, were collected twice a year (in spring and autumn), providing six time intervals for the development of our models. We applied seemingly unrelated regression to analyze the height growth in this polycyclic species, allowing us to model spring and autumn height increments at the same time. Our results showed that seedling height growth depended on the silvicultural treatment, meteorological conditions during the spring growth season, inter-specific scrub competition, position within the gap, and seedling characteristics, such as the ontogenetic development or the size of the seedling itself. This work, along with germination and survival analysis, aims to provide a holistic perspective on the suitability of the group selection cutting system to regenerate maritime pine stands, taking into account current and future climate change scenarios.

Human Mesenchymal Stem Cells on Size-Sorted Gelatin Hydrogel Microparticles Show Enhanced In Vitro Wound Healing Activities.

The demand for innovative therapeutic interventions to expedite wound healing, particularly in vulnerable populations such as aging and diabetic patients, has prompted the exploration of novel strategies. Mesenchymal stem cell (MSC)-based therapy emerges as a promising avenue for treating acute and chronic wounds. However, its clinical application faces persistent challenges, notably the low survivability and limited retention time of engraftment in wound environments. Addressing this, a strategy to sustain the viability and functionality of human MSCs (hMSCs) in a graft-able format has been identified as crucial for advanced wound care. Hydrogel microparticles (HMPs) emerge as promising entities in the field of wound healing, showcasing versatile capabilities in delivering both cells and bioactive molecules/drugs. In this study, gelatin HMPs (GelMPs) were synthesized via an optimized mild processing method. GelMPs with distinct diameter sizes were sorted and characterized. The growth of hMSCs on GelMPs with various sizes was evaluated. The release of wound healing promoting factors from hMSCs cultured on different GelMPs were assessed using scratch wound assays and gene expression analysis. GelMPs with a size smaller than 100 microns supported better cell growth and cell migration compared to larger sizes (100 microns or 200 microns). While encapsulation of hMSCs in hydrogels has been a common route for delivering viable hMSCs, we hypothesized that hMSCs cultured on GelMPs are more robust than those encapsulated in hydrogels. To test this hypothesis, hMSCs were cultured on GelMPs or in the cross-linked methacrylated gelatin hydrogel (GelMA). Comparative analysis of growth and wound healing effects revealed that hMSCs cultured on GelMPs exhibited higher viability and released more wound healing activities in vitro. This observation highlights the potential of GelMPs, especially those with a size smaller than 100 microns, as a promising carrier for delivering hMSCs in wound healing applications, providing valuable insights for the optimization of advanced therapeutic strategies.

Investigating non-uniform corrosion induced concrete cover cracking with a fracture-contact coupled computational method

Corrosion of steel rebar causes cracks in concrete, significantly impacting the durability of reinforced buildings. While various computational methods aim to simulate this process, only a few successfully handle both internal corrosion pressure and surface crack width evolution. To address this limitation, the study introduces an innovative mesoscale fracture-contact coupled computational method that seamlessly integrates with ABAQUS. Unlike current methods, it creatively utilizes interface elements to model stress transfer and crack propagation under tension in concrete. Additionally, it includes an additional contact model to represent the material's response to compression and shear forces. These innovations allow for accurate simulation of plain concrete mechanical properties under both tension and compression, effectively illustrating the development and failure patterns of cracks in the reinforced concrete cover. After calibrating and validating the method, the study thoroughly analyzed the process of concrete cover cracking, considering factors such as water to cement ratio, spatial location, geometry and size of coarse aggregate, rebar diameter and cover thickness. The modeling results reveal the following findings: (i) Changes in the shape and size of coarse aggregates have minimal effects on internal pressure and crack width. (ii) Higher concrete strength correlates with increased pressure on the outer surface of the rebar in an almost linear fashion, but it has little impact on surface crack width. (iii) Increasing the bar diameter decreases rust pressure but results in more cracks and wider surface cracks. (iv) Augmenting the cover thickness intensifies rust-induced pressure while simultaneously widening surface cracks.

Influence of the inner diameter of the bottom plate on the cleaning performance of double-layer filter cartridges

Dust collectors are used in various industries to separate pollutants from the air. Filter cartridge dust collectors are favored for their stability and small footprint. However, conventional cleaning techniques make it difficult to solve the problem of incomplete cleaning of filter cartridges, which require frequent replacement. Inner cone double-layer filter cartridges are utilized to improve the incomplete cleaning of filter cartridges. The size of the inner diameter (ID) of the bottom plate is one of the main factors affecting the cleaning performance of the double-layer filter cartridge. Double-layer filter cartridges' inside flow field is investigated by numerical simulation in this work. Selection of evaluation indexes such as peak static pressure and comprehensive pressure to assess cleaning performance and analyze the effect of ID on cleaning performance. It was shown that increasing ID could optimize the upper section of the filter cartridges' static pressure distribution. Both larger (ID = 160 mm) and smaller (ID = 40 mm) filter cartridges ID possessed better bottom static pressure accumulation capacity. As the inner diameter of the bottom plate decreases, the cleaning performance increases and then decreases, and the best results were obtained at an ID of 140 mm, with a PC of 1175 Pa. Notably, IDs exceeding 160 mm have a significant negative impact on the cleaning performance of the filter cartridges.

Impact on casting die diameter size on microstructure and fractographic studies of Al2024 alloy reinforced with fly ash and SiC hybrid composites

AbstractThe development of metal matrix composites is important for industrial applications that require lightweight materials with high strength, stiffness, and wear resistance. In this investigation, Al2024 alloy was reinforced with fly ash and silicon (SiC) carbide hybrid composites using the stir‐squeeze cast technique. Two sets of composites were fabricated: one with 3 wt% fly ash and 3 wt% SiC, and the other with 3 wt% fly ash, 5 wt% SiC, and 3 wt% fly ash, 7 wt% SiC The composites were prepared using 25 and 75 mm diameter dies. Microstructural characterization of the specimens was performed using scanning electron microscope, X‐ray powder diffraction, and energy dispersive X‐ray spectroscopy analysis. Mechanical properties, such as yield strength, ultimate tensile strength, and hardness, were determined according to American Society for Testing and Materials standards. The hybrid composites fabricated in the 25 mm diameter cast iron molds exhibited superior mechanical properties compared to those prepared in the 75 mm diameter molds. The addition of fly ash and SiC particulates enhanced the mechanical properties of the Al2024 alloy. These composites showed improved strength, toughness, and ductility.

Boiling mechanism of biphilic surfaces based on Helmholtz instability and Taylor instability

This study demonstrated that combination hydrophilic copper and hydrophobic nano-silver surfaces simultaneously enhanced the critical heat flux (CHF) and heat transfer coefficient (HTC) in pool boiling heat transfer (BHT) with deionized water as the employed working fluid. To further investigate the influence of geometric factors on heat transfer, this study designed three patterns denoted as squares/stripes/networks, ranging from 50 μm to 3000 μm. The effects of pattern size d, spacing p, and pitch ratio p/d on heat transfer results were obtained. Based on bubble visualization, the study further analyzed the reasons for inflection points in the boiling curve and the mechanisms caused by porous hydrophobic coating. Finally, the study proposed a numerical model suitable for predicting CHF of biphilic surfaces based on Helmholtz instability and Taylor instability. The model began with vapor columns escaping toward far-field and the fluid supplied to the heating surface. Concrete model derivation and adjustments are categorized according to the relationship between pattern size and bubble detachment diameter. For surfaces where the bubble detachment diameter exceeds the pattern size, this study originated from the perspective of Helmholtz instability on the vapor column surface. The resulting model is anticipated to quantitatively solve for the former and modulate the wavelength of Taylor instability on biphilic surfaces. Regarding surfaces with bubble detachment diameters smaller than the pattern size, this research begins with the existence time of the micro-liquid layer. The derived model validates the predominant role of p/d in the CHF values on micron-scale biphilic surfaces.

Characterizing street trees in three metropolises of central China by using Street View data: From individual trees to landscape mapping

Street trees can benefit urban spaces, and the characterization of them is a basis for evaluating their functions and proper management. In this paper, we speculate that Street View imagery-based measurement favors characterizing street trees from individual tree sizes and growth status to spatial mapping and risk region identification at multiple city levels. Using Wuhan, Changsha, and Nanchang as examples, nearly 6000 sites and over 111,000 Baidu Street View (BSV) images were used to measure tree sizes, growth status, and vertical structure. Together with BSV-derived tree data, we also calculated the street-view greenness index (GVI) and the Normalized Difference Vegetation Index (NDVI) from remote sensing data, and then city-level spatial mapping was produced to identify risk regions for urban afforestation. The results showed that BSV measurement could compare city-level street trees, i.e., Changsha had a 1.2–1.3-fold higher diameter, tree height, and canopy size than the lowest at Nanchang; Changsha had the highest GVI, but the lowest NDVI; while Nanchang had the lowest GVI, but the highest NDVI, showing different significance between street-view and remote-sensing greenness. BSV data could identify urbanization effects, i.e., the tree sizes decreased from the urban center to the edge, and three cities showed the same pattern. By using BSV data, the growth status score was summarized from leaf blade color, tree-supported, dieback, and dead-tree percents, and thereafter, urbanization-induced decreases of growth status scores can be observed from the city center to the suburbs. At the same urban-rural gradient, BSV data found the vertical structure tended to be complex, and the sky and middle GVI decreased while the ground GVI rose in all three cities in general. The BSV data made landscape mapping available, and the map can be used to identify risk areas of big-sized tree conservation, health problems, greenness deficiency, and the over-simplified forest structure within a city or among different cities. Together with BSV-derived street development data, complex associations between tree characteristics and geo-climates and street social development could be decoupled by redundancy ordination. In general, streets with more pedestrians were often accompanied by taller, larger, healthier trees, more complex communities, and an increasing sky/ground ratio of GVI greenery. Our findings highlighted that street-view data could be used to assess street tree characteristics, geographic distribution, and possible associations with other factors, favoring the city-level urban tree inventory from individuals to the landscape for urban tree management and policymaking.

Study of Lightweight Ceramic Matrix-Less Syntactic Foam Composed of Cenosphere Using Spark Plasma Sintering.

The current investigation presents porous ceramic materials prepared with cenospheres (CS) by using spark plasma sintering. The impact of sintering temperature, mould diameter (20, 30 and 50 mm) and cenosphere size on the properties of the sintered material was investigated. Shrinkage of the samples during sintering started at 900 °C. Total sample shrinkage during sintering increases with increasing temperature and decreases with increasing mould size; increasing sample sintering temperature increases the apparent density of all sample series CS 63-150 µm in a 20 mm mould from 0.97 to 2.3 g·cm-3 at 1050-1300 °C; in a 30 mm mould, 0.81-1.87 g·cm-3 at 1050-1200 °C; in 50 mm mould, 0.54-0.75 g·cm-3 at 1050-1150 °C; while CS 150-250 µm in a 20 mm mould is 0.93-1.96 g·cm-3 at 1050-1200 °C. Total porosity decreases from 61.5% to 3.9% by increasing sintering temperature from 1050 to 1250 °C, while open porosity reduces at lower temperatures, with closed porosity being highest in samples sintered at 1150 °C. When the sintering temperature increases from 1050 to 1300 °C, the compressive strength of the CS 63-150 samples produced in a 20 mm mould increases from 11 MPa to 312 MPa. These results correlate with the Rice model, which describes an exponential dependence of compressive strength on material porosity and fully dense material compressive strength.

Textural Study of Vesicles in Tagish Lake (C2-ung) Meteorite Fusion Crust: Constraints on Vesicle Formation during Their Entry into the Earth’s Atmosphere

Vesicles are characteristic structures within the outer layer of many stony meteorites’ fusion crusts. Although these features are well-developed in hydrated carbonaceous chondrites and some micrometeorites, their formation mechanism remains poorly understood. This study provides new insights into the understanding of physical vesiculation processes by presenting the results of vesicle size distribution (VSD)—i.e., a quantitative method for vesicle analysis—applied to the study of the Tagish Lake (C2-ung) meteorite fusion crust. Tagish Lake was chosen because it shows a scoriaceous texture and a significant number of vesicles (about 24,000 vesicles/mm2), thus allowing statistical analysis. Vesicles range from being spherical to irregular-shaped and from a few μm to ~70 μm (equivalent diameter) in size. Vesicle size distribution and cumulative number density analyses show a high nucleation event and a fractal distribution of the vesicle population, respectively. We suggest these features are due to disequilibrium degassing processes, which simultaneously produce continuous/accelerating vesicle nucleation and growth. Finally, possible analogies between the scoriaceous Tagish Lake fusion crust and the space-weathered “frothy layer” on the surface of Ryugu’s grains could be found in terms of vesicularity.