Flux Values Research Articles

Suffusion characteristics of a heterogeneous dam foundation with a cut-off wall of stochastic defects

Natural alluvial foundations are inherently heterogeneous. To enhance seepage safety, a cut-off wall is commonly embedded in a dam foundation. However, walls can also have stochastic defects. The dual uncertainties arising from soil heterogeneity and wall defects pose significant challenges for seepage safety evaluation. In this study, systematic numerical simulations were conducted on an internally unstable dam foundation based on a four-constituent mixture framework. Soil heterogeneity was characterized by stochastic initial hydraulic conductivity and initial fines content. An erosion model, specifically incorporating the influence of overburden pressure, was employed to quantify suffusion. A probabilistic assessment utilizing Monte Carlo simulations revealed that suffusion in heterogeneous fields could be more severe than that in homogeneous fields. Various combinations of stochastic soil properties and defect locations can result in substantial disparities in seepage and erosion fields. The mean values of the total flux and the fines eroded ratio are insensitive to the spatial variation length, while their deviations increase with increasing spatial variation length, leading to larger uncertainties in the leakage channel morphology. For highly heterogeneous alluvial foundations with large spatial variations, conventional seepage and suffusion analyses that rely on homogeneous assumptions may considerably underestimate the internal erosion risk.

Experimental evaluation and artificial neural network modeling of heat transfer performance of aerosolized magnesium oxide nanoparticles flow through pipes

This study presents a novel approach to modeling the convective heat transfer coefficient (CHTC) of aerosolized magnesium oxide (MgO) nanoparticles in a circular pipe using artificial neural network (ANN) technique, by leveraging experimental data. The work addresses a gap in existing research on the heat transfer characteristics of nanoaerosols under varying thermal and flow conditions. MgO nanoparticles (30-50 nm) were dispersed in compressed air at volume fractions of 0.005, 0.01, and 0.05 to generate the nanoaerosol. This aerosol was then driven through the pipe at volumetric flow rates between 10 and 50 liters per minute (lpm). The pipe was subjected to controlled heat fluxes of 4546.83 W/m², 9093.66 W/m², and 13640.49 W/m² to evaluate the aerosol heat transfer coefficient (AHTC). Experimental results demonstrated that incorporating MgO nanoparticles significantly enhanced the heat transfer coefficient by up to 1.4 %, 111 %, and 89.7 % at the specified heat flux values, corresponding to increases in the volumetric flow rate from 10 lpm to 50 lpm, respectively. An ANN-based correlation was developed to model the heat transfer coefficient in relation to heat flux, particle volume fraction, and volumetric flow rate. This model accurately predicted the experimental data, achieving a mean absolute percentage error (MAPE) of 9.9 × 10-5, a mean square error (MSE) of 0.038433, and a coefficient of determination (R²) of 0.99. These findings confirm the ANN model's efficacy in predicting the enhancement of the nanoaerosol heat transfer coefficient and provide a robust tool for future thermal management applications involving nanofluids.

High Pressure Melting Curve of Fe-Si: Implication for the Thermal Properties in Mercury's Core.

The motion of liquid iron (Fe) alloy materials in the outer core drives the dynamo, which generates Mercury's magnetic field. The assessment of core models requires laboratory measurements of the melting temperature of Fe alloys at high pressure. Here, we experimentally determined the melting curve of Fe9wt%Si and Fe17wt%Si up to 17GPa using in situ and ex situ measurements of intermetallic fast diffusion that serves as the melting criterion in a large-volume press. Our determined melting slopes are comparable with previous studies up to about 17GPa. However, when extrapolated, our melting slopes significantly deviate from previous studies at higher pressures. For Mercury's core with a model composition of Fe9wt%Si, the melting temperature-depth profile determined in our study is lower by ∼150-250K when compared with theoretical calculations. Using the new melting curve of Fe9wt%Si and the electrical resistivity values from a previous study of Fe8.5wt%Si, we estimate that the electronic thermal conductivity of liquid Fe9wt%Si is 30 Wm-1K-1 at the Mercury's CMB pressure of 5GPa and 37Wm-1K-1 at an assumed ICB of 21GPa, corresponding to heat flux values of 23mWm-2 and 32mWm-2, respectively. These values provide new constraints on the core models.

The transport and vertical distribution of microplastics in the Mekong River, SE Asia

Rivers are primary vectors of plastic debris to oceans, but sources, transport mechanisms, and fate of fluvial microplastics (<5mm) remain poorly understood, impeding accurate predictions of microplastic flux, ecological risk and socio-economic impacts. We report on microplastic concentrations, characteristics and dynamics in the Mekong River, one of the world’s largest and polluting rivers, in Cambodia and Vietnam. Sampling throughout the water column at multiple localities detected an average of 24 microplastics m-3 (0.073mgl-1). Concentrations increased downstream from rural Kampi, Cambodia (344km from river mouth; 2 microplastics m-3, 0.006mgl-1), to Can Tho, Vietnam (83km from river mouth; 64 microplastics m-3, 0.182mgl-1) with most microplastics being fibres (53%), followed by fragments (44%) and the most common polymer being polyethylene terephthalate (PET) or polyester. Pathways of microplastic pollution are expected to be from urban wastewater highlighting the need for improved wastewater treatment in this region. On average, 86% of microplastics are transported within the water column and consequently we identified an optimum sampling depth capturing a representative flux value, highlighting that sampling only the water surface substantially biases microplastic concentration predictions. Additionally, microplastic abundance does not linearly follow discharge changes during annual monsoonal floods or mirror siliclastic sediment transport, as microplastic concentrations decrease rapidly during higher monsoon flows. The findings reveal complex microplastic transport in large rivers and call for improved sampling methods and predictive models to better assess environmental risk and guide policy.

Formulation and Evaluation of Niosomal Loaded Transdermal Patches for the Treatment of Osteoarthritis

Introduction: Osteoarthritis (OA) is a degenerative joint disease resulting from the breakdown of joint cartilage and underlying bone. The most common symptoms of osteoarthritis are joint pain and stiffness. The major hurdle in its treatment is that the oral administration of NSAIDs (Lornoxicam) causes side effects like GI side effects, cardiovascular problems, liver is-sues, or renal problems. Thus, there is a need to develop a Transdermal drug delivery system for the transport of drugs, which reduces side effects and has several benefits over oral delivery, and a Novel drug delivery system to enhance the permeation of drugs and give relief from symptoms of OA. Objectives: This work deals with the formulation and evaluation of niosomal-loaded Transdermal Patches for the treatment of Osteoarthritis. Method: The Niosomes were prepared using the thin film hydration method, and Niosomal-loaded Transdermal patches were prepared using the Solvent Casting method. The preliminary evaluation and characterization studies were conducted to find the optimized formulation. The in-vitro release and ex-vivo permeation studies were investigated. Stability studies were also assessed. Result: The prepared Niosomes suspension (F2) was found to have particle size 320.2 nm, Zeta potential 23.9 mV, and Drug entrapment 79 ± 0.32%. The in-vitro drug release studies of opti-mized formulation show 96.44 ± 0.34 % drug release for 24 hours. Then, the optimized Niosome formulation (F2) was loaded into the transdermal patches. The in-vitro permeation studies of Nio-somal-loaded transdermal patch F1 (NLXTP) were performed, which showed a higher permeabil-ity than plain drug-loaded transdermal patch. F1 (NLXTP) followed Zero order release kinetic model, which shows a non-fickian controlled release diffusion mechanism. The ex-vivo drug re-lease studies of optimized formulation F1 (NLXTP) show 2.79 ± 0.76 (μg/ml) drug permeated for 8 hours with a flux value of 0.35 ± 0.55, and the percentage of drug retention was found to be 5.67%. The stability studies showed that patches were stable over 90 days in different atmospher-ic conditions. Conclusion: The Lornoxicam-loaded Niosomal transdermal patch was found to be a promising nano-drug-delivery alternative that showed better entrapment and release with a permeation pro-file for the daily management of osteoarthritis.

Influence of hydrogen content in tokamak scrape-off-layer on performance of lithium divertor

Abstract Self-replenishing liquid metal coatings are considered as a perspective divertor design able to withstand challenging particle and power loads of a fusion tokamak-reactor. Numerical modeling of the scrape-of-layer (SOL) plasma with advanced 2D codes, such as SOLPS, is necessary for developing of the ‘liquid-metal’ divertor. In this work we report on upgraded version of SOLPS 4.3 code liquid metal erosion module implemented earlier in our group and present results of simulations of T-15MD tokamak with Li-covered divertor plates. The erosion model includes all main processes Li erosion, i.e. physical sputtering, thermal sputtering, evaporation, and prompt redeposition. Unlike some other available implementations, Li atoms are considered in kinetic approximation in our version. A detailed analysis of Li erosion and flow in T-15MD configuration for various powers (6–12 MW) and H content in the SOL is presented. It is shown that the most of eroded Li particles are redeposited on the divertor targets, however, in some regimes absolute Li flow from the divertor is still large and might lead to significant main plasma dilution with Li. Vapor shielding effect is pronounced on both divertor targets in the most reasonable regimes providing low peak heat flux values at the target plates, less than 10 MW m−2. The target erosion rate and surface temperatures are within limits of the most target designs. Moreover, in strongly shielded cases the target temperature can be even lower than the Li melting temperature meaning that external heating is required to keep Li flowing. Sensitivity analysis shows that our results are most sensitive to the target heat conduction parameters, i.e. the target thickness, outer surface temperature. It means that controlling the target cooling rate can be a useful tool for controlling the liquid Li divertor regime. Variation of the Li erosion rate parameters has little effect on the divertor performance.

Determination of threshold values of parameters of electronic irradiation of glass leading to electrostatic discharges

Experimental data are presented on the minimum values of energies and flux densities of electrons, the impact of which on the cover glasses of solar batteries and reflecting elements of thermoradiators of artificial Earth satellites leads to electrostatic discharges. It has been established that the addition of protons to the composition of the particle flux acting on the studied samples can suppress the development of discharges. For a qualitative interpretation of the results obtained, a mathematical model is proposed.

Pool boiling on the aluminum alloy, copper and WC-coated copper with micro-finned textures and developed multimodal roughness formed by nanosecond laser radiation

Boiling remains one of the most effective processes allowing heat to be removed from heat-loaded surfaces of technological equipment. Due to the development of technologies for metal surface treatment with laser radiation to form specified near-surface properties, including the type, texture configuration and wetting properties, the task of substantiating the use of heat transfer surfaces modified by laser radiation to intensify the boiling process has become relevant. The pool boiling characteristics in distilled degassed water (before the boiling crisis onset) were compared experimentally on the surfaces of samples made of aluminum alloy, copper, and WC-coated copper. Experimental samples were treated by two different methods, including widely used polishing with abrasive materials and laser radiation. Nanosecond laser treatment was used to make micro-finned and anisotropic (developed hierarchical roughness) textures. Textured samples were then hydrophobized. As part of the experiments on pool boiling, the characteristics of the forming bubbles were recorded on the prepared surfaces, heat transfer coefficients, and critical heat flux values were determined. Experimental results were compared with predicted characteristics using well-known models. The evolution of the functional properties of laser-textured metal surfaces after prolonged exposure to heat flux, which is typical of the operating modes of modern heat-loaded equipment, was assessed.

Net Primary Production Simulation and Influencing Factors Analysis of Forest Ecosystem Based on a Process-Based Model

Accurate assessment of net primary production (NPP) can truly reflect the carbon budget balance of the forest ecosystem. In this study, the boreal ecosystem productivity simulation (BEPS) model was used to simulate the NPP of Saihanba mechanized forest farm in 2020, and the influencing factors of NPP were analyzed. The meteorological, forest cover, leaf area index (LAI) and other data required for the model, as well as the data for verifying, were from field surveys or downloaded from different sources. The results showed that: (1) Within the scale of the flux tower, the diurnal variation of NPP reached a maximum in June. The monthly average peak value of latent heat flux was in June, and the sensible heat flux was in March. The temperature of the understory canopy was mostly higher than that of the overstory canopy and air temperature. (2) At the regional scale, the total NPP in the study area in 2020 was 4.25 × 1011 g C a−1, with an average of 564.71 g C m−2 a−1. The annual average NPP of silver birch (Betula platyphylla) was the largest, and the total NPP of northern Chinese larch (Larix principis-ruprechtii) was the largest. (3) NPP was highly sensitive to LAI. Topographic factors had effects on NPP. The average value of NPP was relatively high in the shady slope and the gentle slope.

Numerical simulation of cathode-spot crater and droplet formation with linear and circular motion process

Abstract In this paper, a three-dimensional cathode spot erosion model is proposed to study the development of cathode spot motion &amp;#xD;process on the surface of copper cathode. The formation and development process of cathode spots motion without external &amp;#xD;magnetic field is studied. In this model, energy flux density, pressure, and current value are considered as external parameters. &amp;#xD;The simulation results compared the cathode spot ablation trajectories and temperature distribution under different motion &amp;#xD;forms and motion velocities. The results indicated that during the spots expansion process, the flow of liquid metal will form a &amp;#xD;convex structure on the surface of the cathode and a hollow structure inside the cathode. Comparing different motion types, the &amp;#xD;annular motion significantly increased the roughness of the cathode surface. With the increase of the speed of spots movement, &amp;#xD;the interaction between the craters is significantly weakened, which will reduce the temperature and the roughness of the &amp;#xD;cathode surface. The simulation results are consistent with the experimental results.

Influence of Clear Felling on СО2 Emission from the Podzolic Soil Surface of the Coniferous-Deciduous Forest (Middle Taiga, Komi Republic)

The impact of industrial logging on the carbon cycle of boreal forests is characterized by significant uncertainties, which is largely due to the lack of information on carbon fluxes (in particular, soil respiration) in felling sites. The aim of study is to assess the effect of clear felling on CO2 emission from the soil surface of a coniferous-deciduous forest on a typical podzolic soil (Albic Retisol). The investigation was executed during the snowless periods (May-October) of 2020–2022 in a coniferous-deciduous forest and its felling site carried out in the winter of 2020. The carbon dioxide emission was measured by a LI COR 8100 gas analyzer. A brief description of the weather conditions during the years of research and the dynamics of soil temperature at a depth of 10 cm is given. A positive, statistically significant relationship between soil respiration and soil temperature at a depth of 10 cm (R2 = 0.17–0.75; p 0.001) was detected for the analyzed objects. The correlation with soil moisture was both positive and negative and statistically insignificant except data obtained in 2022 in the undisturbed control forest. The high values of CO2 flux during the snowless period were observed in July–August and was 3.90–5.62 gC/ m2/ day and 2.3–2.5 gC/m2/day in undisturbed forests and felled areas, respectively. In 2021, the peak of CO2 release shifted to June. Clear felling has a negative effect on the soil respiration of Albic Retisol that decreased by 1.2–1.9 times in the conditions of the middle taiga of the Komi Republic. The most (55–66%) of the C–CO2 efflux during the snowless period was emitted during the summertime, and the vegetation period (May–September) contribution was 84–88%. The obtained data will serve to determine the role of industrial logging in the carbon cycle of taiga forests.

Efficient Lithium Recovery from Water Using Polyamide Thin-Film Nanocomposite (TFN) Membrane Modified with Positively Charged Silica Nanoparticles.

The separation of Li+ from Mg2+ in salt-lake brines using nanofiltration (NF) has become the most popular solution to meet the rising demand for lithium, particularly driven by the extensive use of lithium-ion batteries. This study presents the fabrication of a uniquely designed polyamide (PA) thin-film nanocomposite (TFN) membranes with ultrahigh Li+/Mg2+ selectivity and enhanced water flux by covalently incorporating mixed ligands functionalized silica nanoparticles (F-SiO2NPs) into the selective PA layer and covalently bonding them to the membrane surface. In this strategy, bare silica nanoparticles (SiO2NPs) were functionalized with mixed superhydrophilic ligands, including primary amine and quaternary ammonium groups, resulting in a highly positive surface charge primarily from the quaternary ammonium groups and enabling covalent conjugation via amine groups. Among the F-SiO2NP-incorporated membranes, M500 containing 500 ppm of F-SiO2NPs exhibited the best performance. In a solution with 2000 ppm salt concentration (Li+/Mg2+ ratio of 1:20), the M500 membrane showed an improved Li+/Mg2+ selectivity of 7.41 compared to the nonmodified TFC membrane, which had a selectivity of 5.05. Further surface conjugation of the M500 sample with 1500 ppm of F-SiO2NPs resulted in the C1500 membrane, demonstrating the best performance among all of the surface-modified membranes. C1500 showed an outstanding Li+/Mg2+ selectivity of 37.95, with a Mg2+ rejection of 95.7% and a Li+ rejection of -63.2%, and a water flux of 56.0 L m-2 h-1 at 70 psi. Notably, a 7.5-fold improvement in Li+/Mg2+ selectivity over the TFC membrane was achieved without compromising the water flux. This is evident from the nearly identical water flux values of the TFC, M500, and C1500 membranes, which were 57.1, 54.8, and 56.0 L m-2 h-1, respectively. Considering key factors for large-scale applications, such as cost-effectiveness, environmental impact, the abundance of synthetic precursors, and the maturity of synthesis and tailoring technologies, SiO2NP-based modifications outperform all other reported approaches to date.

Applicability of monitoring data of Hg soil-atmosphere transport in an old mining area for exposure risk assessment

Mercury (Hg) is a widespread pollutant that poses significant risks to both ecosystems and human health. While previous studies have evaluated Hg concentrations in soils, few have measured Hg emissions in areas with high Hg concentrations or related these measurements to estimates of exposure via air inhalation based on Hg flux values. This study addresses this gap by proposing the use of gaseous elemental Hg (GEM) flux measurements for exposure risk assessments, with a particular focus on the importance of inhalation exposure, which has implications for future risk management strategies. Sensitivity analysis of the site-specific exposure and risk estimation model revealed that the fraction of land area in surface water significantly impacted the estimated exposure through air inhalation. Additionally, the analysis showed that the GEM flux measured in situ in a high-Hg concentration area of Itomuka was not directly proportional to the Hg concentration, although the risk estimation model treated it as a function of concentration. Furthermore, we found that the flux values are influenced by both the fraction of land area in surface water and Hg concentration, indicating that this new flux-based indicator should be integrated into exposure risk assessments.

Tailoring cilnidipine nanostructured lipid carriers loaded transdermal patch for the treatment of hypertension: optimization, ex vivo and in vivo studies

The current investigation aimed to develop nanostructured lipid carriers (NLCs) as a potential transdermal drug delivery system for the improvement of cilnidipine (CIL) bioavailability. The high-pressure homogenization (HPH) method was utilized for the formulation of NLCs. Box-Behnken Design (BBD) was utilized to optimize CIL NLCs for entrapment efficiency, particle size and zeta potential. The resultant NLCs had a mean particle size of 98.2 ± 05.08 nm, a zeta potential of −16.1 ± 2.05 mV and an entrapment efficiency of 92.51 ± 4.18%. Transmission electron microscopy (TEM) revealed spherical or elongated particles for CIL-NLCs. The optimized NLCs were embedded in the transdermal patch and were formulated utilizing the solvent casting method and investigated for CIL content, physical characteristics, skin permeation and in vivo pharmacokinetics study. In vivo pharmacokinetics experiments with an NLCs-embedded transdermal patch show, an increase in C max and T max , 1305.66 ± 7.96 ng/mL and 4 h, respectively, when compared to the oral CIL dose. The flux values for ex vivo permeation studies for the CIL NLCs patch were determined to be 82.54 ± 4.80 µg/cm2/h. The bioavailability of CIL-loaded NLCs transdermal patch was found to be 2.9-fold greater than that of oral drug suspension, thus confirming the improvement of bioavailability of CIL by NLCs loaded transdermal patch.

The Contribution of Siliceous Plankton to Vertical Export Flux in the Eastern Mediterranean: A Comparative Study of the North Aegean, Cretan, and Ionian Seas

This study investigates the intricate dynamics of siliceous plankton species within the open marine regions of the Greek Seas, focusing on their seasonal and spatial variability. For this purpose, vertical export fluxes of diatoms (DtF), silicoflagellates (SF), and radiolaria (RF) were analyzed in three sediment trap time series obtained from the North Aegean, Cretan, and Ionian Seas. Special attention was given to diatom assemblages, resulting in the estimation of the DtF community structure and diversity for each studied site. Diatom flux values reached 353.9 × 103 valves m−2 day−1, 77.7 × 103 valves m−2 day−1, and 42.4 × 103 valves m−2 day−1 in the North Aegean, Ionian, and Cretan Seas, respectively. SF maxima were 1309.8 × 103 skeletons m−2 day−1 in the North Aegean Sea, 35.2 × 103 skeletons m−2 day−1 in the Ionian Sea, and 11.9 × 103 skeletons m−2 day−1 in the Cretan Sea (South Aegean Sea). RF values reached 13.9 × 103 radiolaria m−2 day−1, 11.9 × 103 radiolaria m−2 day−1, and 5.4 × 103 radiolaria m−2 day−1 in the North Aegean, Ionian, and Cretan Seas, respectively. The North Aegean Sea exhibited significantly higher mean total fluxes, particularly for diatoms, driven by the north-to-south oligotrophy gradient, which was influenced by riverine inflows and the nutrient-rich Black Sea water. In the Cretan and Ionian Seas, convective mixing and atmospheric deposition, especially during increased rainfall (precipitation) events, were identified as primary drivers for the increased siliceous plankton fluxes recorded in the late winter–spring months. Diatom communities were dominated by Naviculales and Fragilariales; the prevalence of the former in the North Aegean Sea is likely linked to the higher nutrient levels in its upper photic zone, as Naviculales includes species with a high affiliation to nutrient enrichment.

Sustainable desalination through hybrid photovoltaic/thermal membrane distillation: Development of an off-grid prototype

Global freshwater scarcity is a critical challenge, particularly severe in remote Australian communities where seawater intrusion and aquifer salinisation exacerbate the need for alternative water resources. Conventional desalination technologies are energy-intensive and unsuitable for rural areas. This study introduces a novel, off-grid, sustainable desalination solution utilising solar-integrated membrane distillation (MD) technology. An innovative, stand-alone prototype combining a hybrid photovoltaic/thermal (PV/T) system with direct contact MD (DCMD) has been designed and developed. This fully integrated PV/T collector efficiently supplies the thermal and electrical energy required for the MD process. The photovoltaic panel generates the necessary electrical energy, while the heat from the PV panel warms the MD system’s feed solution, enhancing overall efficiency through the solar cell cooling effect. In addition, an innovative fan-cooled radiator equipped with two DC fans with a low power consumption rating was designed and customized to be applied as MD system cooling medium within the outdoor setting. The concept development and feasibility of the system are explored in detail through a comprehensive experimental investigation employing an innovative and practical approach to design and examine the integrated hybrid solar MD unit. This unique system was designed, constructed, and tested under dynamic outdoor conditions, during the summer season in Melbourne, to assess the integration strategy and evaluate its long-term operational performance. The performance of the integrated PV/T-MD system was evaluated using two commercial hydrophobic membranes with different pore sizes under various outdoor conditions and PV/T fluid flow rates. Key performance metrics analysed include solar irradiance intensity, temperature profiles of the PV/T panel and MD module, power, current and voltage profiles of the unit components, permeate flux, specific water productivity (SWP) and the thermal (ηthermPV/T) and electrical (ηelecPV/T) efficiencies, along with the gained output ratio (GOR). Comprehensive experimental assessments in indoor and outdoor settings were undertaken to confirm the technical viability of the system. The study demonstrates the feasibility of such systems through real-world trials and addresses key challenges in energy efficiency and internal heat recovery. The experimental trials demonstrated permeate flux values ranging between 8–16 kg/m2h outdoors, compared to 22–30 kg/m2h indoors, reflecting the impact of fluctuating environmental conditions. The system’s power consumption was measured 130–140 W, about one-third of the PV/T power rating. The maximum power generation reached 280 W in battery charging mode. achieving a maximum ηthermPV/T of 20 % and an ηelecPV/T of 18 %. Additionally, the cooling effect of the PV/T panel resulted in a 1.5–2 °C temperature reduction, improving electrical power output by 0.8–1.2 %. The findings highlight the significant potential of the system in providing reliable and efficient freshwater production in remote, off-grid communities, offering a scalable solution to address global water scarcity challenges.

The Impact of Partial Solar Eclipse on the Observation of Neutral Hydrogen Emission Line

The research involves examining the influence of partial solar eclipse on the strength of neutral hydrogen from the Sun. Baghdad University Radio Telescope (BURT) was used to monitor the partial solar eclipse on the 25th of October, 2022. Radio observations from the Sun were recorded from 11:30 AM to 03:36 PM. This means that the HI emission from the Sun was recorded before, during and after the event. It was noticed, that at the moment of maximum eclipse, ~ 46% of the Sun’s disk was covered by the Moon. For the purpose of this research, the solar radio wave intensity was monitored and the solar flux density was determined at different times, i.e. before, during and after the partial solar eclipse. The obtained results showed that both of the solar flux and power spectrum decrease with the progress of the eclipse until the moment of maximum eclipse, i.e. the moment at which the minimum values of solar flux density and antenna temperature were recorded (7 × 104 Jy and ~ 80 K). Then, at the last moments of the partial eclipse, it was noticed that both parameters started to increase again due to the decrease in the area of the Sun’s disk until both reached their normal values. In Conclusion, the partial solar eclipse affects the strength of neutral hydrogen from the Sun because the Moon blocks the neutral hydrogen from the Sun during the solar eclipse.

Spatio-temporal variations of the heat fluxes at the ice-ocean interface in the Bohai Sea

Thermodynamic process between the ice and the ocean plays a critical role in the evolution of sea-ice growth and melting in marginal seas. At the ice-ocean interface, the oceanic heat flux and the conductive heat flux transmitted through the ice layer jointly determine the latent heat flux driving the phase change (i.e., ice freezing/melting). In this study, the determination of two important thermal parameters in the ice module of the HAMSOM ice-ocean coupled model, namely the mixed layer thickness and the heat exchange coefficient at the ice-ocean interface, has been adjusted to improve the model performance. Spatio-temporal variations of heat fluxes at the ice-ocean interface in the Bohai Sea are investigated, based on the validated sea ice simulation in the 2011/2012 ice season. The relationships between the interfacial heat fluxes and oceanic and atmospheric conditioning factors are identified. We found that the surface conductive heat flux through ice shows short-term fluctuations corresponding to the atmospheric conditions, the magnitude of these fluctuations decreases with depth in the ice layer, likely due to reduced influence from atmospheric conditions at greater depths. Atmospheric conditions are the key controlling factors of the conductive heat flux through ice, while the oceanic heat flux is mainly controlled by the oceanic conditions (i.e., mixed layer temperature). Spatially, the value of the oceanic heat flux is larger in the marginal ice zone with relatively thin ice than in the inner ice zone with relatively thick ice. In the Bohai Sea, when ice is growing, heat within the ice layer is transferred upward from the ice base, and the heat is losing at the ice-ocean interface. This heat loss in the inner ice zone is obviously greater than that in the marginal ice zone. Whereas when ice is melting, the opposite is true.

Introducing the SNW-1 Covalent Organic Framework to the Polyamide Layer of the TFC-RO Membrane with Enhanced Permeability and Desalination Performance.

This study investigates the synthesis and characterization of Schiff base network-1 (SNW-1) covalent organic framework (COF) nanomaterials and their application in the fabrication of thin-film nanocomposite (TFN) membranes. The embedding of SNW-1 COF in reverse osmosis (RO) membranes with a polysulfone (PSf) substrate was done using the interfacial polymerization method. The result of the study demonstrated that the porous and hydrophilic structure of the COF increased the hydrophilic properties of the produced RO membranes. When the COF was embedded with a concentration of 0.02 wt %, the hydrophilicity of the RO membrane was higher than that of the other membranes, with a contact angle value of 45.2°. Pure water flux, saline solution flux, and humic acid (HA)/sodium chloride (NaCl) foulant solution flux were measured to determine the membrane performance, and it was found that as the COF ratio increased, the fluxes increased up to a certain concentration rate. The RO membrane with a SNW-1 concentration of 0.005 wt % had the highest values of pure water flux and saline solution flux with high salt rejection (34.2 and 32.2 LMH, 97.1%, respectively) and was the most resistant membrane against fouling. This study presents the potential of the SNW-1 COF with precise design capabilities and controlled unique properties as an additive for desalination applications.

Cocrystallization Enables Ensitrelvir to Overcome Anomalous Low Solubility Caused by Strong Intermolecular Interactions between Triazine-Triazole Groups in Stable Crystal Form.

Ensitrelvir is a nonpeptide 3CL protease inhibitor used for coronavirus disease 2019 treatment. Four crystalline forms of ensitrelvir, metastable (Form I), acetonate (Form II), stable (Form III), and hydrate (Form IV), have been analyzed as pharmaceutical crystals. Their rank order of solubility is Form I > IV > III. Form III is the stable crystal with a significantly lower solubility than that predicted from its log P value of 2.7. Here, single-crystal structural analysis revealed strong intermolecular interactions between the triazine (acidic) and triazole (basic) groups of Form III not Forms I and IV. Multicomponent crystals were also designed to improve the solubility by altering the intermolecular interactions in Form III. Slurry conversion with equal molar ratios of ensitrelvir and fumaric acid successfully induced the formation of a novel cocrystal (Form V). Fumaric acid inhibited the triazine-triazole interactions, and dissolution of Form V was approximately 8- and 13-fold higher than that of Form III in pH 1.2 and 6.8 media, respectively. Furthermore, Form V exhibited an approximately 16-fold higher flux value than that of Form III. Therefore, alterations in intermolecular interactions via cocrystallization significantly enhance the dissolution and permeation of ensitrelvir.