Mixing Intensity Research Articles

A Study on the Influence Mechanisms of Neighborhood Vitality and the Characteristics of Spatial and Temporal Differentiation in the Urban Fringe Areas of Wuhan City

Achieving effective integration of urban–rural relationships and promoting the flow of resources between urban and rural areas in megacities are a key priority in the development of China’s new urbanization efforts. As a transitional zone between urban and rural areas, the urban fringe is the frontier of urban–rural integration. The specific research object of this paper is the urban fringe areas of Wuhan City. This paper quantifies the neighborhood vitality of the fringe areas by the short-stay visitors in the fringe areas and selects the 5D elements of the built environment and social media data from multiple sources to construct the indicator system assessing the neighborhood vitality of the urban fringe areas. This paper analyzes the spatial distribution characteristics of neighborhood vitality and its influencing factors in urban fringe areas and investigates the connection between neighborhood vitality and its influencing factors through the application of the multi-scale geographically weighted regression (MGWR) model. Based on the regression results, relevant planning recommendations are made on how to enhance the vitality of neighborhoods in urban fringe areas. The results show that the index system constructed by “5D” elements of built environment and social media data can well explain the spatial distribution of neighborhood vitality in urban fringe areas. Among the influencing factors, the absolute value of the correlation coefficient of network exposure is the largest, followed by road density and functional density. Thanks to the different bandwidths given by MGWR to the influencing factors, the global influencing factors are only two indicators—development intensity and functional mixing degree—while the other influencing factors are all local, and the influence degree of different regions is different, so it is necessary to analyze and put forward different planning suggestions accordingly.

Oceanic eddy with submesoscale edge drives intense air-sea exchanges and beyond

Oceanic mesoscale eddies influence air-sea interaction and atmosphere dynamics through ventilating heat and moisture upward. However, whether the sea surface temperature (SST) gradient on the eddy edge could affect the heat and moisture release is still unknown because of the limited observations and coarse-resolution climate models. Using high-resolution atmospheric simulations, this study compares the atmospheric response to the mesoscale (~ 40 km) and submesoscale (~ 4 km) SST gradients at the edge of an eddy. Results show that submesoscale SST gradient drives stronger surface heat and moisture fluxes, enhancing the vertical mixing intensity by 2–3 times within and above the marine atmospheric boundary layer. As a result, one local precipitation event is found to be an order of magnitude larger overlying the eddy. Our findings highlight the importance of resolving oceanic submesoscale features for accurately predicting atmosphere dynamics and precipitation over the ocean.

POSSIBILITIES OF SYNTHESIS OF UNCHARGED STABLE LATEX PARTICLES FOR IMMUNOANALYSIS

Objective: The objective of this study is to find a method for synthesizing uncharged polystyrene latex particles whose surface can be easily modified. Theoretical basis: The main method of latex synthesis is emulsion polymerization. Latexes for a specific purpose can be obtained by polymerization in heterogeneous monomer-water systems, without the use of emulsifiers, both with intensive mixing of the system and under static conditions. In this work, polymerization was carried out without the use of emulsifiers in a static monomer-water system. Method: To achieve the set goal, the possibility of obtaining latex particles using a hydrophobic initiator - ditrile of azoisobutyric acid - was investigated by carrying out polymerization in a diffusion mode in a three-phase system monomer - water - initiator. Results and discussion: The results of the study showed that the latex obtained in the three-phase system is stable. It is assumed that the stability is due to the presence of hydroxyl end groups groups of polymer molecules on the surface of the latex particles, which are formed as a result of the reaction of the initiator with water and initiate polymerization. The synthesized latexes retained stability for a year. Practical value: Latexes can be used in all those areas of science and technology where the absence of a charge on the surface of latex particles is required. Originality/value: The originality of the work lies in the fundamental simplicity of the synthesis and the unambiguity of the results obtained.

Predicting chlorophyll-a dynamics in the Ashtamudi estuary using ANN and ANFIS techniques

Excessive nutrients and associated high chlorophyll-a concentration are of growing concern to the public health due to the occurrence of eutrophication in aquatic bodies. Continuous monitoring of chlorophyll-a has limitations, thereby necessitating the development of prediction models. Even though chlorophyll-a prediction models are numerous, they rarely fit into estuarine conditions, which is encountered with dynamic mixing of freshwater and sea water. Thus, the present study identifies the most appropriate driving factors that are relevant for estuarine conditions through chlorophyll-a prediction models developed using Artificial Neural Network and Adaptive Neuro Fuzzy Inference System (ANFIS) approaches in the Ashtamudi estuary, India. Salinity, which is an indirect measure of the estuarine mixing intensity, has been used to replicate the dynamic mixing in the estuary. The results indicate that the model incorporating salinity along with total nitrogen, total phosphorous and turbidity well-predicted chlorophyll-a concentration with a coefficient of determination ranging from 0.73 to 0.99. General Regression Neural Network (GRNN) and ANFIS models outperformed Back Propagation Neural Network (BPNN) and Recurrent Neural Network (RNN) models. Of the various ANFIS models, the ones that used Gaussian and Generalized Bell membership functions were most appropriate for the prediction of chlorophyll-a than the models with triangular and trapezoidal membership functions. The study identified that the models that considered salinity were less sensitive and can be used for modelling chlorophyll-a. The chlorophyll-a was observed to have a direct influence of salinity at salinity values greater than 5‰. The study highlighted that estuarine mixing further enhances the primary productivity through increased penetration of light leading to higher chlorophyll-a concentration. Further the study emplasized that the predictive models are important tools fitting well within estuarine environments due to its replicability.

Analysis of hydrodynamics and thermal–hydraulic performance of twisted angle fins within an annular conduit

AbstractThis paper investigated the influence of various twisted angles of fin inserts integrated on the inner heated pipe wall of a double-pipe heat exchanger by analysing the thermal–hydraulic performance through numerical simulations. Results showed twisted angle fin (TAF) induced turbulent fluid flow phenomena, generating transverse and longitudinal vortices, along with swirling flow. This collaboration between the vortices and swirling flow effectively prevents heat trapping and enhances heat transfer from the inner pipe wall through the intensive fluid mixing. Despite longitudinal swirling vortices and turbulence significantly enhance local and global heat transfer performance, they led to increased pressure drop. However, TAF twisting reduces pressure drop by streamlining flow. The performance evaluation criterion (PEC) value is a dimensionless quantity that facilitates the comprehensive evaluation of optimal configurations by comparing the increment in Nusselt number and the increment in friction factor. PEC values greater than 1 indicate that the increase in Nusselt number exceeded the increase in friction factor. Among tested configurations, the twisted fin angles of 60° (TAF60) exhibited the highest improvement in Nusselt number and friction factor, also achieving the highest PEC of 1.59712 at Reynolds number of 1194.71. TAF40 and TAF50 were identified as optimal configurations for enhancing the thermal–hydraulic efficiency, with average PEC values of 1.26893 and 1.27030, respectively. Overall, the study indicated a consistent enhancement trend with increasing twisted angles and emphasizes the significant thermal performance improvement of TAF configurations compared to the smooth conduit. Furthermore, the results showed a converging tendency across all TAF configurations in the percentage improvement in Nusselt number and friction factor, as well as PEC compared to the baseline No fin configuration with increasing Reynolds number, suggesting that future improvements in thermal–hydraulic performance are more dependent on geometric angles than fluid flow velocity.

Statistical modeling of the effects of wind speed, air temperature and relative humidity on the concentration of carbon monoxide in the urban atmosphere

The high carbon monoxide content in the urban atmosphere is one of the most important indicators of poor air quality in megacities such as Moscow. This study is to evaluate the importance of wind speed, air temperature, and relative air humidity for predicting the concentrations of carbon monoxide for the day ahead using a simplified one-dimensional quasistationary statistical model. It is shown that the concentration of carbon monoxide in the Moscow atmosphere is determined by a combination of internal (previous days CO concentration) and external (meteorological conditions) factors. The variation of carbon monoxide concentration at one station differs from the variation at another station due to the differences in local conditions. Taking into account wind speed and air temperature increases the predictive value of the onedimensional quasi-stationary statistical model for most of the stations. In contrast to wind, relative air humidity decreases the predictive value of the model for most of the stations. This means that meteorological factors considered in this study could have different effects on predicting carbon monoxide concentration in the case of Moscow. The data from the Balchug weather station, located in the city center, offers a more accurate CO concentration forecast for most Moscow stations compared to the VDNKh weather station. For a more complete description of the influence of meteorological conditions on the predicted low concentration of gases, it is useful to take into account the model wind direction, surface air pressure, and the intensity of mixing in the urban boundary layer.

Gas–liquid mixing performance of a non‐Newtonian fluid in a multiple‐impeller agitated tank

AbstractBACKGROUNDThis target is to decide power input and gas hold‐up for gas–liquid mixing aqueous CMC solutions. The analysis considers the impact by varying the impeller speed and gas flow rates in a stirred tank bioreactor of three kinds of multiple impellers. The effects of the impeller type, rheology, and operating conditions were investigated on power drawn, relative power demand (RPD), gas holdup, and volumetric mass transfer coefficient.RESULTCompared to the Rushton turbine (6RT) and 4‐pitch blade (4PBT) impeller, the propeller (3PP) impeller presented a minimal event of the gassing on the RPD. 4PBT impeller has shown a higher gas hold‐up compared to the Rushton turbine and propeller impellers. The aerated agitated tank was established a dimensionless correlation for the RPD as a function of flow number and web number. Besides, the gas–liquid agitated system was also introduced a dimensionless correlation to compute the overall gas hold‐up as a function of specific power consumption. For the maximum dispersion mixing intensity, the impeller structure with low RPD looks to be more adequate. Further, maximizing gas holdup in the structures with high RPD is advantageous. The effects of impeller speed, gas superficial velocity, and rheology on the volumetric mass transfer coefficient were examined.CONCLUSIONThe volumetric mass transfer coefficient increased with an increase in impeller speed, gas superficial velocity, and power consumption per unit volume and decreased as rheology increased. The averaged kLa for each multiple‐impeller was correlated well with the specific gassed power consumption and gas superficial velocity. © 2024 Society of Chemical Industry (SCI).

Morphology Regulation of Organophosphate Crystals by Micro‐Jetting Technique

AbstractOrganophosphates nucleating agents are widely used in the plastics industry. Nucleating agents with different morphologies have various effects on the resin materials. The micro‐jetting technique is shown to be a promising tool for the controlled preparation of micro‐and nano‐sized particles. Therefore, in this paper, controllable preparation of sodium 2,2'‐methylene‐bis‐(4,6‐di‐tert‐butylphenyl) phosphate (NA11) is achieved by the micro‐jetting technique. The study focused on the impact of various parameters on its shape and size. Hexagonal, rhombic, rod‐shaped, and needle‐shaped micro‐sized NA11 crystals are prepared. The results show that the decrease in the polarity of the organic solvents added in the antisolvent water led to the transformation of NA11 from bulk hexagon to plate‐like rhombus and finally to needle‐shaped crystals. The addition of surfactants can regulate the crystal growth rates and orientations, thereby facilitating the formation of rod‐shaped crystals. Based on rod‐shaped crystals, the crystal size is studied. Crystals with average particle sizes in the range of 40–100 µm can be obtained with coefficients of variation as low as 4% by varying the relevant experimental parameters such as the supersaturation, the solution homogeneity in the crystal growth environment, and the mixing intensity. This study provides references for designing functional materials.

Reactive crystallization regulation for synthesizing NCM811 precursor by different impellers

The spherical and dense precursors with a narrow particle size distribution are essential to achieve high electrochemical performance in cathode materials. Four newly designed impellers, including the punched-flow turbine (PFT), punched-flow disc turbine (PFDT), curved-inclined-blade disc turbine (CIBDT), and 6-folded-pitched turbine (FPT-6), are applied to prepare the precursors to investigate the interplay among the fluid flow state, precursors’ morphology and growth, and physicochemical properties of cathodes. The flow and mixing features of double impellers are predicted using computational fluid dynamics, indicating that the FPT-6 plays a crucial role in crystal nucleation while PFDT facilitates crystal growth. This concurrence can be corroborated by examining the performance of precursors synthesized using these four impellers. It is first found that the electrochemical performance is distinctly enhanced by utilizing different impellers to regulate the specified nucleation and growth stage. By increasing the nucleation rate with double impellers of FPT-6, the tap density and sphericity of the precursor and cathode materials are significantly improved. The discharge capacity of cooperative agitators (FPT-6+PT) is 2.1 times that of the only propeller turbine at a high current density (10 C). The later growth stage is suitably regulated by FPT-6 or PFDT; properly extended reactive time can enhance the sphericity and electrochemical performance. The dual mixed-impeller (PT/CIBDT) combines intense mixing and shear ability, attaining a dense spheroid with a highly smooth surface. The cycle retention of this cathode is increased by 10.35% after 200 cycles at 1 C compared to a commercial counterpart. A regulatory strategy for the reactive co-precipitation process to enhance precursor stability is proposed here. Furthermore, the optimal operation parameters derived from this strategy can be effectively applied to commercial cathode materials.

75-Year dynamics of the Black Sea phytoplankton in association with eutrophication and climate change

Based on a database containing species records obtained from 1948 to 2022 and a hydrochemical database, long-term changes in the biomass and taxonomic structure of phytoplankton in the deep-sea basin of the Black Sea were analysed in the stratified period from April to October. Over 75 years, a significant increase in concentration of nitrate, a weak increase in phosphate and a strong decrease in dissolved silicate were observed in the nutricline. The biomass of diatoms and total phytoplankton increased several times during the peak of eutrophication in 1991–1993, then decreased by the 2000s and has again shown an increasing trend in the last 15 years. The number of species dominant in biomass has halved from the 1940s–60s to the 2010s. The primary beneficiaries were the large- and medium-celled diatoms Pseudosolenia сalcar-avis and Proboscia alata, as well as the coccolithophore Emiliania huxleyi, the main dominant species of the last decade. Most noticeable was the increase in the amplitude and duration of the regular annual May–July bloom of E. huxleyi. Over the past three decades, its biomass has increased by more than an order of magnitude, accounting for about 40 % of the total phytoplankton biomass. Development of the large- and medium-celled diatoms, as well as the decrease in biomass of silicoflagellates, can be, at least partly, associated with the long-term decline in dissolved silicate in the upper layers. The trend towards a decrease in dinoflagellate biomass is probably associated with increased mixing intensity in the water column. Over the study period, the total phytoplankton biomass was positively related to nitrate stock in the water column. Short-term period (from one to several years) interannual variability was influenced predominantly by hydrophysical processes, primarily the intensity of winter convection. After cold winters with intense involvement of deep nutrients in the upper layers, the biomass of diatoms, coccolithophores and total phytoplankton increased. Thus, fluctuations in winter weather or local climate reduced or enhanced the effect of eutrophication, sometimes leading to the time gap between the peak in nitrate stock and phytoplankton biomass. The case of the Black Sea illustrates the complex pattern of the response of a marine ecosystem to the simultaneous impacts of anthropogenic and climate changes, leading to significant alterations in the functioning of the biological carbon pump.

The impact of the destruction of the Kakhovka reservoir dam on the oceanographic conditions in the north-western part of the Black Sea according to the results of modeling

Based on the results of numerical modelling, characteristic features of distribution of transformed and polluted waters of the Dnieper River in the water area of the north-western part of the Black Sea (NWBS) are determined and analyzed. This pollution of the marine environment resulted from the extremely large man-made flood caused by the destruction of the Kakhovka Reservoir dam by the Russian occupation forces in June 2023. Various types of pollutants, which contained in the Kakhovka Reservoir, in the lower Dnieper River and in the bottom sediments, were carried out into the sea by the flood discharge. A significant amount of pollutants was washed into the sea from the flooded areas of the lower Dnieper basin. Special attention is given to changes in oceanographic conditions in the Dnieper-Bug estuary region (DBR) of the Black Sea, which determine the extent of marine pollution. Sea water salinity was used as an indicator of the degree of infiltration of polluted seawater from the estuary into the sea. It was identified that the least transformed river waters with low salinity correspond to high pollution levels. Delft3D-Flow Flexible Mesh hydrodynamic model, developed by Deltares, was used in this study. The simulation was performed for the time period 01 to 30 June 2023. During the first days after the dam break the desalinated and polluted transitional waters, flowing from the Dnieper-Bug estuary, spread over the entire water column down to 15-20 m depth in the DBR area. In this case, the spreading of transitional waters was atypical, as it usually occurs only within the thin near-surface layer of the sea. By mid-June the flow of transitional water with a salinity of 4-6 ‰ covered the entire water column from surface to bottom near the northern coast of the NWBS and over the Odessa Bank. This was facilitated by the supermassive volumes of transformed Dnieper river waters flowing out over a short period of time due to dam break, as well as by the resulting intense gradient currents and mixing caused by spatial gradients in the velocity of the generated currents. The width of the desalinated water plume and its area in the bottom layer were smaller than in the surface layer. The largest vertical salinity gradients were formed to the south of the Odessa Bank, where salinity was 4-6 ‰ in the surface layer and 14-17 ‰ in the bottom. Dilution of the desalinated water plume in the bottom water layer was much more intensive than in the surface water. The character of water circulation pattern in the northern part of the NWBS in the first days after the inflow of transient waters from the Dnieper-Bug estuary was determined by the runoff gradient currents, which later were replaced by wind-driven currents in the Odessa area and over the Odessa Bank, and by the meandering flow of gradient density currents further south. The findings of this study contribute to a better understanding of the impact of the inflow of transformed river waters from the Dnieper-Bug estuary on the variability of oceanographic characteristics and the ecological state of marine waters in the Dnieper-Bug region of the northwestern Black Sea.

Assessment of process parameters on modified 316L SS surfaces prepared via hybrid powders mixed EDM

This study aims to assess the influence of hybrid powders (hydroxyapatite, manganese, copper, and carbon nanotube) mixed electric discharge machining (EDM) and coating process on 316L stainless steel (SS). An efficiently machined, hydrophilic, thin, and microporous surface is produced using variable discharge energies and powders weighted percentage suspended in the dielectric medium. The research outcome indicates that the hybrid powders mixed-EDM process synthesised a coating that substitutes the base elements with foreign elements of calcium (Ca), phosphorous (P), copper (Cu), carbon (C), oxygen (O), and manganese (Mn). The surface wettability response of the coating displays a hydrophilic nature with a contact angle of 51.5° and surface energy of 52.9 mJ m−2. The coated surface exhibited a roughness value of 3.201 μm, which is expected to promote osseointegration, and the material removal rate has been enhanced to an optimal value of 100.32 mg/min. The Taguchi design demonstrated that the powder mixing ratio, current intensity, and spark time are the most influential factors in the hybrid powders mixed EDM process. This study determines a novel multiple additives-assisted EDM method to synthesise a coating on 316L SS with potential benefits for biomedical applications.

Head-on collision of gravity currents of unequal strengths: Large-eddy simulations and laboratory experiments

The collision of two counterflowing gravity currents with unequal strengths was investigated through large-eddy simulations and laboratory experiments. The collisions were initiated by releasing currents from two partial-depth locks at identical heights but with different densities, characterized by the reduced gravity ratio, γg. By varying γg, we elucidate the transport processes of colliding gravity currents, spanning from comparable driving strengths (γg=1.0) to markedly disparate driving strengths (γg≪1). Three distinct regimes of colliding gravity currents were identified based on kinematic features derived from integrated measures. For γg≥0.92, the collisions are driven by counterflowing gravity currents with comparable driving strengths, leading to nearly symmetrical collisions with negligible impact on evolved flow patterns. In the intermediate regime when 0.4<γg<0.92, the collisions are weakly asymmetric, characterized by differing contact surface steepness and insensitive maximum vertical displacement of ascending motions to γg. For γg≤0.4, strongly asymmetric collisions dominate, featuring minimal vertical convective fluxes in the collision region rather than typical colliding currents. In this flow regime, the denser fluid mass intrudes beneath the less dense one, akin to the propagation of intrusive lock-exchange gravity currents. Additionally, mixing rates over the entire flow domain were quantified using background potential energy calculations. The results reveal that intense diapycnal mixing is predominantly driven by stirring processes before collision, with the mixing rate increasing as γg decreases. From the collision stage onward, currents with the gain of inertia converge within the collided region and move upward with the distinct opposite effect of negative buoyancy. Notably, the mixing rate stabilizes regardless of convective process variations and decreases consistently as the currents slump away from the collision region.

Disposal of used oils as a prospective method of production of biodiesel

The article is devoted to the improvement of the production technology of diesel biofuel from waste oils, which are a significant source of environmental pollution. Environmental pollution is one of the biggest environmental problems of our time. Used oils that are not properly disposed of cause serious environmental problems, including water and soil pollution. The use of waste oils for the production of biofuel is a promising technology that allows reducing the amount of pollution and reducing dependence on fossil fuels. Biodiesel from waste oils has significant environmental, economic and sustainable advantages. The main goal of the article is a detailed analysis of modern technologies for the production of diesel biofuel from waste oils and an assessment of their improvements and impact on ecology, economy and society. The article discusses innovative approaches to the processing of used oils, their purification and preparation for further use. An analysis of the main methods of transesterification, hydrogenation, esterification and enzyme catalysis, as well as the latest technologies, such as ultrasonic and microwave intensification of biofuel production, was carried out. New technological solutions for the preliminary preparation of used oils with a high content of free fatty acids using a combination of acid catalysts are proposed, and a technological scheme of the full production cycle is developed. The rational parameters of the equipment for the preliminary preparation of used oils with a high content of free fatty acids have been determined. Recommended conditions include hydrogenation temperature not higher than 80°С, duration of the process not less than 40 minutes; separation of the water-protein part by centrifugation at a rotation frequency of the centrifuge rotor of 3000 rpm for 20 minutes; the esterification reaction temperature is no more than 60°C; molar ratio of alcohol to oil 9:1; acid catalyst concentration within 1-15%; the intensity of mixing in the reactor is 31.42 s-1; the duration of the process is not less than 120 minutes. It was established that it is advisable to use potassium hydroxide for the transesterification reaction. The use of potassium hydroxide is beneficial because the potassium salts formed during the technological process of diesel biofuel production can be used as mineral fertilizers. According to the results of the research, the optimal parameters for the transesterification reaction were chosen: the amount of methanol - 20% by mass. from the weight of the oil, the KOH 1 catalyst is 1.5%, the temperature of the process is 60°C and the duration is 60-70 minutes. Examples of successful implementation of these technologies in various countries of the world, in particular in Europe, the USA and Asia, are presented. Additionally, recommendations are provided for further research and technology development, including the need to improve waste oil purification methods, optimize transesterification processes, and integrate renewable energy sources. The prospects and challenges of the industry of biofuel production from waste oils are considered, in particular the issues of regulatory support, financial incentives and investment attraction.

Tubular photobioreactor design based on mixing intensity

A novel design methodology for tubular photobioreactors (TPBRs) for the mass culture of microalgae that can account for mixing intensity is presented. To date, TPBRs have been mainly designed and operated under the assumption of perfect mixing with regard to photosynthesis performance (light integration regime). In this work we show that this simplification has been leads to significant errors in the prediction of the optimal dilution rate and biomass productivity. To this end, computational fluid dynamics and light distribution model have been employed to calculate the trajectories and light histories I(t) of a microalgal cell population represented by 50 particles of 5 μm diameter. The density of the microalgal cells was set at 1000 kg m−3 and the tube diameters (D) were 14, 24, 44, 64 and 84 mm, with the circulation velocities (v) ranging from 0.4 to 1 m s-1. This has been coupled to a dynamic photosynthesis model in order to calculate the average photosynthetic response and hence the integration factors in TPBRs. It has been demonstrated that for a generic microalgal strain, the use of the light integration simplification (Γ = 1) would result in the prediction of an optimal dilution rate of 0.0315 h−1 (for D = 14 mm and v = 0.4 m/s as an example), which would lead to an actual biomass productivity of 182.5 g biomass m−3h−1 if the predicted integration factor (Γ = 0.578) is used whereas the newly proposed method predicts an optimal dilution rate of 0.0125 h−1 and a biomass productivity of 362.3 g biomass m−3h−1. This demonstrates that simplifying the light integration regime is inadequate for TPBRs design and operation, resulting in significant inaccuracies. The estimation charts and regressions proposed in this work to estimate actual integration factors will enable the development of an optimization method for TPBRs based on mixing intensity.

Machine learning revealing overlooked conjunction of working volume and mixing intensity in anammox optimization

Extensive studies on improving anammox performance have taken place for decades with particular focuses on its operational and environmental factors, but such parameter-based optimization is difficult, because of the sheer number of possible combinations and multidimensional arrays of these factors. Utilizing machine-learning algorithm and published anammox data, Bayesian nonparametric general regression (BNGR) was applied to identify the possible governing variable(s) from among 11 operating and environmental parameters: reactor type, mixing type, working volume, hydraulic retention time, temperature, influent pH, nitrite, ammonium, nitrate concentration, nitrogen loading rate, and organic concentration. The results showed that working volume is a key but oft-overlooked governing parameter. By integrating the BNGR findings with computational fluid dynamics simulation, which assessed mixing properties, it became feasible to conclude that working volume and mixing intensity co-regulated flow fields in reactors and had a significant influence on anammox performance. Furthermore, this study experimentally validated how mixing intensity affected performance, and specific input power (x), a parameter that conjugates both working volume and mixing intensity, was used to establish the relationship with ammonium removal rate (NH4+-N RR, y) y = 49.90x+1.97 (R2 = 0.94). With specific input power increased from 3.4 × 10−4 to 2.6 × 10−2 kW m−3, the ammonium removal rate exhibited a rise from 1.8 to 3.2 mg L−1h−1. Following, a relationship among input power-working volume-nitrogen removal rate was also established with a view to determining the design variables for anammox reactor. Consequently, the study highlighted the necessity to consider the working volume-mixing intensity correlation when optimizing the anammox process.

Oil in food waste to methane by anaerobic digestion: Co-effects of mixing intensity and long chain fatty acid loading

Oil in the food waste can contribute improved energy yield by anaerobic digestion, and also poses an inhibition risk from the intermediate long chain fatty acids (LCFAs). The digestion performance partly depends on the solubility of oil/LCFAs concerned recently, while mixing intensity control can disturb the solubility characteristics. Combined with oil loading such a fundamental control parameter, co-effects of mixing intensity and oil loading on methanogenic characteristics were illuminated. A series of mixing intensities 0–240 rpm and oil/inoculum (F/I) ratios 0.2–1.2 were set to conduct a batch experiment, and relevant affecting mechanisms were further disclosed as well. It turned out that variation of mixing intensity could have effects on methanogenesis from oil in food waste. Increasing mixing intensity prolonged lag phase. Mixing intensity at 120 rpm was proved as a starting point to disturb LCFA inhibition. Methanogenic rates climbed to the top at F/I 0.4, and further increase loading resulted in the rate decline. Methanogenic potential release was also reduced with both mixing intensity and loading at higher values. Hereinto, oleic acid (C18:1) as a key LCFA in oil played an important role in inhibition, while higher mixing intensity and loading could promote degradation and conversion of another critical LCFA palmitic acid (C16:0). The study favors achieving a cost-effective strategy controlled by mixing intensity to promote safe energy improvement.

Investigation of an Industrially Scalable Production of Sulfur‐Polyacrylonitrile Based Cathodes

AbstractSulfur‐polyacrylonitrile (SPAN) is a sulfur‐based active material for next‐generation lithium‐sulfur battery cathodes. Due to the covalent bonding between sulfur chains and the polymeric backbone, the shuttle effect degrading classical sulfur‐based cathodes can be suppressed while also achieving a high active material content in the cathode. In this paper, we investigate the processability of an industrially scalable SPAN active material with 38 wt.‐% of sulfur in a water‐based and scalable process route. The potential of the SPAN material for industrial adoption and the impact of the process route on the cell performance are discussed. We show that when processed correctly, the SPAN material delivers exceptional cycling stability and good C‐rate performance with ether‐based electrolytes. However, the performance of the SPAN cathode is influenced by the mixing characteristic. Using higher mixing intensities during the slurry preparation leads to deterioration of the electrochemical performance. This can be attributed to a decreasing carbon black percolation with increasing tip speed in combination with the kinetic limitation of sulfur cathodes during Li2S2 and Li2S oxidation.

High-intensity focused ultrasound ablation in the treatment of fumarate hydratase-deficient uterine leiomyoma

Objective This study aimed to explore the efficacy and safety of high-intensity focused ultrasound (HIFU) ablation for treating fumarate hydratase (FH)-deficient uterine leiomyomas. Method Ten patients with FH-deficient uterine leiomyomas treated with HIFU ablation at the Third Xiangya Hospital from July 2017 to January 2023 were enrolled in this study. The effectiveness and adverse effects of HIFU were analyzed. Results The median age of the patients who received HIFU was 32.0 years (range: 28–41 years). Only 2 patients had solitary uterine leiomyomas, whereas the remaining 8 patients had multiple uterine leiomyomas. The median diameter of the largest myoma was 56 mm (range: 41–99 mm). Magnetic resonance imaging showed that the FH-deficient uterine leiomyomas of 8 patients presented as mixed intensity on T2WI, that of one patient was hypointense, and that of another patient was hyperintense on T2WI. All patients successfully underwent HIFU ablation in one session without severe adverse effects. The median nonperfusion volume ratio (NPVR) was 40% (30.0%–78.0%) after HIFU treatment. Four patients had NPVR ≥70%. At 3-month follow-up after HIFU ablation, the clinical symptoms of 5 of the 8 patients with symptoms before treatment were relieved. Six months after treatment, 4 of the 8 patients with symptoms were still in remission. All patients received reintervention by March 2024. The reintervention rates were 20%, 70%, and 90% at 12, 24, and 36 months, respectively, after HIFU ablation. Conclusion HIFU is a safe and feasible treatment for FH-deficient uterine leiomyomas, and most patients show effective results in the short term after treatment. However, the reintervention rates are high, and the long-term effects are limited.

Impacts of three inspiratory muscle training programs on inspiratory muscles strength and endurance among intubated and mechanically ventilated patients with difficult weaning: a multicentre randomised controlled trial

BackgroundInspiratory muscle training (IMT) is well-established as a safe option for combating inspiratory muscles weakness in the intensive care setting. It could improve inspiratory muscle strength and decrease weaning duration but a lack of knowledge on the optimal training regimen raise to inconsistent results. We made the hypothesis that an innovative mixed intensity program for both endurance and strength improvement could be more effective. We conducted a multicentre randomised controlled parallel trial comparing the impacts of three IMT protocols (low, high, and mixed intensity) on inspiratory muscle strength and endurance among difficult-to-wean patients.MethodsNinety-two patients were randomly assigned to three groups with different training programs, where each performed an IMT program twice daily, 7 days per week, from inclusion until successful extubation or 30 days. The primary outcome was maximal inspiratory pressure (MIP) increase. Secondary outcomes included peak pressure (Ppk) increase as an endurance marker, mechanical ventilation (MV) duration, ICU length of stay, weaning success defined by a 2-day ventilator-free after extubation, reintubation rate and safety.ResultsMIP increases were 10.8 ± 11.9 cmH2O, 4.5 ± 14.8 cmH2O, and 6.7 ± 14.5 cmH2O for the mixed intensity (MI), low intensity (LI), and high intensity (HI) groups, respectively. There was a non-statistically difference between the MI and LI groups (mean adjusted difference: 6.59, 97.5% CI [− 14.36; 1.18], p = 0.056); there was no difference between the MI and HI groups (mean adjusted difference: − 3.52, 97.5% CI [− 11.57; 4.53], p = 0.321). No significant differences in Ppk increase were observed among the three groups. Weaning success rate observed in MI, HI and LI group were 83.7% [95% CI 69.3; 93.2], 82.6% [95% CI 61.2; 95.0] and 73.9% [95% CI 51.6; 89.8], respectively. MV duration, ICU length of stay and reintubation rate had similar values. Over 629 IMT sessions, six adverse events including four spontaneously reversible bradycardia in LI group were possibly related to the study.ConclusionsAmong difficult-to-wean patients receiving invasive MV, no statistically difference was observed in strength and endurance progression across three different IMT programs. IMT appears to be feasible in usual cares, but some serious adverse events such as bradycardia could motivate further research on the specific impact on cardiac system.Trial registration Clinicaltrials.gov identifier: NCT02855619. Registered 28 September 2014