High Flow Rates Research Articles

Response surface method‐based hydraulic performance optimization of a single‐stage centrifugal pump

AbstractIn this article, the response surface approach was employed to enhance the hydraulic performance of the pump at the rated point. Specifically, an approximate link between the design head and efficiency of the single‐stage centrifugal pump and the parameters of the impeller's design was established. The first step in creating a one‐factor experimental design involved selecting significant geometric variables as factors. Decision variables such as the number of blades, flow rate, and rotation were chosen due to their significant impact on hydraulic performance, while head and efficiency were considered as responses. Subsequently, the best‐optimized values for each level of the parameters were identified using response surface analysis and a central composite design. The impeller schemes of the Design‐Expert software were evaluated for head and efficiency using Computational fluid dynamics, and a total of 20 experiments were conducted. The simulated results were then validated with experimental data. Through the analysis of the individual parameters and the approximation model, the ideal parameter combination that increased head and efficiency by 7.90% and 2.06%, respectively, at the rated value was discovered. It is worth noting that in cases of a high rate of flow, the inner flow was also enhanced.

Evaluating the Success Rate of Distal Femur Intraosseous Access Attempts in Pediatric Patients in the Prehospital Setting: A Retrospective Analysis

Objectives Although the proximal tibia is a common site for intraosseous (IO) line placement in pediatric patients, previously published data indicate high malposition rates in infants and children at this location. Although distal femur IO lines generally demonstrate higher flow rates than those at the proximal tibia, to date, there have been no published studies assessing distal femur IO access in pediatric patients. Thus, we aimed to compare the success rates of pediatric IO line insertion attempts between the proximal tibia and the distal femur in a prehospital setting. Methods We conducted a retrospective chart review of prehospital pediatric patients who underwent at least one IO line placement attempt by Palm Beach County Fire Rescue from May 2015 to January 2024. We excluded records lacking specific documentation of IO attempt location. We compared the unadjusted success rates of distal femur to proximal tibia, and we also compared success rates after propensity score matching and multivariable logistic regression. Secondarily, we assessed the prehospital complication rate of the IO lines at each anatomical site. Results We identified 163 pediatric patients who had an IO attempt and were eligible for analysis. Median age was 1.9 years (IQR: 0.46 to 4.2 years). Among those 163 patients, there were 234 vascular access attempts, including 82 IO attempts at the distal femur and 72 at the proximal tibia. The unadjusted success rate of distal femur attempts was 89.0%, compared to 84.7% for proximal tibia attempts, a difference of 4.3% (95% CI −6.4 to 15.0%). After propensity score matching, we found an adjusted odds ratio of 2.0 (95% CI 0.66 to 6.8), favoring the distal femur for successful placement. Prehospital complication rates were similar for distal femur (5.5%) and proximal tibia (4.9%). Conclusions This retrospective analysis of pediatric patients in a prehospital setting suggests that IO line placement at the distal femur might offer a marginally higher success rate compared to the proximal tibia. Despite not reaching statistical significance, these findings support the consideration of distal femur as a viable option for IO placement in the pediatric population.

A Portable Fluid Administration System for Prolonged Intravenous Fluid Administration in Subadult and Adult White Rhinoceroses (Ceratotherium simum).

While translocations of white rhinoceroses have become an important conservation tool, dehydration during long-distance transports has been identified as a welfare concern. Intravenous (iv) fluid administration might therefore be useful to mitigate dehydration; however, special requirements need to be met to make iv fluid administration suitable for large, wild rhinoceroses during transport. Requirements include a portable and robust system that is capable of delivering high flow rates, is easy to set up, and remains patent and operating for long periods of time while allowing the animals to freely stand or lay down in the transport crates. Due to the lack of suitable fluid administration systems, we developed a custom-made system consisting of 8 L drip bags, a three-part, 4.4-m-long, large bore and partially coiled administration set, and a robust, battery-operated infusion pump, which allowed us to successfully administer iv fluids at a maintenance rate of 1-2 mL/kg/h to eight rhinoceroses for 24 h during a mock transport. While iv fluid administration in transported rhinoceroses is time intensive and the large amount of drip bags required during lengthy transports might pose a limitation, the developed system may be useful for the long-distance transport of small groups of rhinoceroses. Furthermore, this system would be of value for injured or sick rhinoceroses, which require parenteral fluid therapy when commercially available infusion pumps cannot provide the large fluid volumes needed.

An experimental investigation on the performance of direct methanol fuel cell using new anode and cathode flow field designs

This is a comprehensive study of the DMFC through the introduction of new channel designs. A traditional serpentine design with a rib and channel width of 0.8mm on an area of 50mm×50mm is designated as design-1 and used as the reference channel design. Three other new designs are fabricated and tested in comparison with design-1. A 4-outlet, 1-inlet, 4-zone serpentine with 0.8mm of rib and channel width, is designated as design-2. A 4-outlet, 1-inlet, 4-zone serpentine with a converging channel width is designated as design-3. A 4-outlet, 1-inlet, 4-zone zigzag serpentine with a converging channel width is designated as design-4. The study was done in three stages. The first stage investigates the effect of anode channel designs by fixing the cathode design to design-1 and varying the anode designs from design-1 to design-4. The second stage investigates the effect of cathode designs by fixing the anode design to design-1 and varying the cathode designs from design −1 to −4. The third stage investigates the effect of using the same designs at both the anode and cathode sides. All the stages were tested using three anode flowrates (2,5, and 8mL/min) and three methanol concentrations (1, 2, and 3mol/L). Higher concentrations perform better than lower concentrations while lower flowrates perform better than higher flowrates. The percentage improvement by the new designs in comparison to the reference design is: 142%, 94%, and 136% for the first stage; 74%, 125%, and 40% for the second stage; and 16%, -33% and -45% for the third stage, and the order being design −2, −3 and −4 respectively. Design −3 and −4 underperform in the third stage due to the availability of direct paths that boost methanol crossover when using the same design of anode and cathode. The new designs evacuate the CO2 bubbles and byproduct water faster and more efficiently than the reference design.

Flow and heat transfer of non-miscible micropolar and Newtonian fluid in porous channel sandwiched between parallel plates

An analytical approach has been considered to inspect the flow and heat transfer of immiscible Newtonian and micropolar fluid in a porous medium. This study aims to elucidate the Darcy effect on the model in which isotropic porous regions with different permeability are used. The model of the current problem explains that the flow region is divided into two regions: Newtonian fluid flows in the upper layer, and micropolar fluid flows in the lower layer. Different constant temperatures imposed at boundary walls, heat transfer does not affect the pressure gradient. The governing equations are solved analytically by applying a linear differential equation (LDE). The effect of associated physical parameters such as material parameter, Darcy number, Eckert number, Prandtl number, and viscosity ratio on velocity, micro-rotation, heat transfer, flow rate, heat transfer rate, wall shear stress, and Nusselt number have been inspected. The most significant finding of this research work is that increasing the Darcy number signifies enhanced permeability, resulting in a higher flow rate. The heat transfer rate at the top occurs maximum when the material parameter’s range is minimum while raising the viscosity ratio leads to an increasing heat transfer rate at the bottom. Enhancement in material parameter influences Nusselt number and decreases in nature. The findings of our study are verified with the previously established results. The present work has a setup that is useful in petroleum extraction, transport problems in reservoir rock of an oil field, improving nutrient transport and thermal regulation in tissue engineering, and designing more efficient drug delivery systems and biomedical devices.

Biocomposite materials from natural rubber/polylactic acid blends reinforced rubberwood sawdust for producing children's toys

Biocomposite materials are prepared by blending natural rubber (NR) and polylactic acid (PLA) reinforced with rubberwood sawdust (RWS). This study aimed to investigate the effects of PLA grade, NR/PLA blend ratio, and RWS content on flexure, tension, hardness, and water absorption characteristics, including thermal stability. The RWS content significantly affected the physical and mechanical properties of the biocomposite materials. The increasing additions of RWS from 30 to 50 wt% increased the mechanical modulus, hardness, and water absorption but decreased the thermal stability of the biocomposites. Polymer blended with an NR/PLA ratio of 30/70 reinforced with 30 wt% RWS exhibited the highest mechanical strength, whereas a blend ratio of 40/60 was found to be reinforced with 40 wt% RWS. The polymer matrix blended with a higher PLA content resulted in superior biocomposite properties. Thus, the biocomposites with an NR/PLA ratio of 30/70 had better properties than those with a ratio of 40/60. Further, biocomposites with PLA grade of low melt flow rate (6 g/10 min) improved their properties more than that of a high melt flow rate (80 g/10 min). Therefore, the appropriate formulation of biocomposites for producing children's toys is a blend ratio of 30/70 with 2003D PLA grade of low melt flow rate and reinforcement with 30 wt% RWS. The tensile, flexural, and compressive forces of a toy boat prototype were 70.08, 104.9, and 124.8 N, respectively, while the specified standard is 69.0, 69.0, and 113.5 N, respectively, thus meeting the requirements of the American Society for Testing and Materials F963.

Assessing the Potential of Environmental DNA for Monitoring Nature‐Like Bypasses: Erroneous Surveillance Owing to DNA Flow‐Through

ABSTRACTNature‐like bypasses refer to fishways that simulate natural streams. Apart from facilitating fish migrations, bypasses possess the capacity to enhance biodiversity in dammed rivers. Feasibility of environmental DNA (eDNA) as a tool for bypass assessments is unknown. This study investigated fish eDNA in 10 bypasses and their main channels. Initially, the relative DNA flow‐through was estimated in bypasses. Subsequently, the impact of environmental factors and bypasses on fish assemblages was evaluated, and the robustness of the eDNA and electrofishing methods was assessed pertaining to bypass monitoring. The eDNA flow‐through was computed using an equation to estimate the residual DNA at specified distances downstream of the source site. The relative DNA flow‐through was lowest in the longest bypass with low flow rate and highest in the shortest bypass with higher flow rate and was dependent on the DNA decay rate coefficient used. The redundancy analysis revealed significant effects of spatial location, agriculture, catchment area, and bypass length on the species composition. The within‐river analyses indicated significant and nonsignificant bypass effects on species composition and total species richness, respectively. Higher richness and DNA abundance of migratory and threatened species were observed in the bypasses than in the main channels. The eDNA samples displayed higher species richness compared to electrofishing. The species composition of the bypass eDNA samples was intermediate between that of the main channel eDNA and bypass electrofishing samples, which further corroborated performance of eDNA flow‐through in bypasses. Therefore, bypass eDNA samples represented variable mixtures of local and main channel assemblages, indicating relatively low robustness of eDNA for quantitative and spatially accurate bypass assessments. Nevertheless, these results demonstrate practical applicability of eDNA in surveying the presence of desired species and evidence of the benefits of bypasses in supporting biodiversity and species threatened by damming.

Study on the Destruction Law and Main Controlling Factors of Corrosion Product Film in H2S-CO2 Coexistence System

Abstract The failure law and main controlling factors of corrosion product film in this corrosion environment were studied according to the characteristics of H2S-CO2 coexistence in a gas field pipeline, so as to provide guidance for corrosion prevention and control of gas field pipeline. Sediment effects of sand particles in the pipeline on corrosion, the influence of flow rate, dissolved oxygen and sediment on corrosion products were analyzed by conducting corrosion experiments at 0.5m/s, 1m/s and 2m/s, corrosion experiments without oxygen and aerobic conditions. The destruction law of corrosion product film in pipeline and the main controlling factors of corrosion product film in single well pipeline and gathering and transportation line were determined. The results show that high flow rate will cause local damage of corrosion product film and promote pitting corrosion, dissolved oxygen will destroy the integrity of corrosion product film, and sediment is one of the factors causing local corrosion and perforation of pipeline inner wall. The corrosion product film structure of the gas field pipeline will be destroyed and pitting corrosion under the condition of high flow rate, oxygen and sand deposition. Meanwhile, the main control factor affecting the corrosion product film destruction of the gas field single well pipeline is dissolved oxygen, and the main control factor affecting the corrosion product film destruction of the gas field gathering and transportation main line is sediment.

Efficacy of balloon-expandable extreme-low-temperature ventricular epicardial cryoablation: A preclinical proof of concept evaluation

BackgroundCurrent epicardial ablation technologies are limited by the inability to create adequate depth lesions and risk of collateral injury to extracardiac structures. ObjectiveThe purpose of this study was to evaluate the feasibility and efficacy of ventricular epicardial ablation with a novel balloon-expandable extreme-low-temperature (XLT) cryoablation catheter with an embedded insulation pontoon for protection of extracardiac structures, which has been specifically designed for epicardial ablation. MethodsTen healthy swine underwent surgical (n = 6) and subxiphoid percutaneous (n = 4) epicardial access. A total of 3–6 sites were targeted in the right and left ventricular wall for different exposure durations. Ablation was performed with a large footprint (surgical) and smaller footprint (percutaneous) version of the HeartPad (Corfigo Inc., Montclair, NJ) XLT system. The system consists of the balloon-expandable cryoablation catheter and a console. The console vaporizes liquid helium (–269°C) and controls continuous delivery of extremely cold helium gas at high flow rates through a high-efficiency ablation element mounted on an expandable insulation pontoon to protect extracardiac structures. Ablation lesions were assessed by gross pathology and histologic examination. ResultsA total of 42 epicardial lesions were created. Mean lesion depth increased progressively with ablation time (surgical catheter: 11 ± 2 mm at ≤30 seconds, 13 ± 4 mm at 60 seconds, 15 ± 3 mm at ≥120 seconds, P = .001; percutaneous catheter: 10 ± 2 mm at 30 seconds, 14 ± 2 mm at 60 seconds, 16 ± 2 mm at 120 seconds, P = .001). Lesion geometry seemed unaffected by presence and thickness of epicardial fat. One episode of ventricular fibrillation occurred after ablation over the atrioventricular groove and 2 adjacent obtuse marginal arteries. ConclusionSurgical or percutaneous epicardial ablation using the HeartPad XLT cryoablation system is feasible and can efficiently produce deep ventricular lesions in different epicardial locations.

Characterising the discharge of hillslope karstic aquifers from hydrodynamic and physicochemical data (Sierra Seca, SE Spain)

Groundwater flow has been investigated in the Sierra Seca, Spain. Maximum recharge to the central core of the mountain occurs at high elevations, which provides recharge to two overlapping karst aquifers constituting a groundwater storage zone at a lower elevation break in slope. Both karst aquifers are associated with three springs arising from the upper part of the permeable formations. The climate is characterized by long and intense periods of drought and short periods of rainfall, which trigger discharges from the springs. Spring flow recession curve analysis, cross-correlation and monitoring of groundwater temperature and electrical conductivity have demonstrated contrasts observed in the hydrodynamic and physicochemical response of the three springs during flood events. One spring records floods with narrow and short peaks of high discharge accompanied by sharp drops in temperature and electrical conductivity. Another spring records floods with somewhat wider peaks and sharp increases in temperature and electrical conductivity (piston effect), whereas the third spring shows great consistency in all monitored characteristics. It is concluded that the absence of a piston effect in the spring with the highest flow rates is due to the contribution of rapidly circulating water that is expelled by semi-active karst networks (overflow) before reaching the saturated zone, which does not occur in the other springs due to the absence of overflow hydrological pathways. The most regular spring owes its functioning to the contribution of infiltrated water in the bed of an upstream riverbed, which explains this regularity.

Microstructure and mechanical property of high-density 7075 Al alloy by compression molding of POM-based feedstock

Metal injection molding of aluminium alloy (MIM-Al) attracts attention, owing to the lightweight, corrosion resistance and good thermal conductivity. However, it is hard to fabricate high-quality MIM-Al due to the hard-to-sinter powder and poor mechanical properties. Here, we report a facile compression molding process for fabricating high-density 7075Al alloy parts using polyformaldehyde (POM)-based feedstock. Pressureless sintering with a high nitrogen flow rate was adopted to promote sintering densification process. The wetting behavior, rheological properties, and morphology of the feedstock were characterized, showcasing the shear-thinning behavior and suitable viscosity for POM-PP-SA binder. Through controlling the compact pressure, mold temperature and holding time, green gear part with good shape retention and dense microstructure was achieved. Influence of process factors and sintering temperature on the microstructure and mechanical properties of 7075Al alloy are investigated. Remarkably, the aluminum alloy components sintered at 610 °C exhibited excellent performance, with a relative density reaching 97.6 % and a tensile strength of 214.8 MPa. This achievement provides a foundation for the industrial application of complex-shaped aluminum alloy components through the compression molding process.

Machine learning assisted mechanism modeling for gas phase electrohydrodynamic system

In this paper, a hybrid physics-data driven model for electrohydrodynamic gas system (EHDGS) was developed by combining artificial neural network (ANN) with mechanism modeling method. ANN was used to correlate the relationship between the variables (electrode distance, diameter of grounding cylinder, applied voltage, electric field gradient, etc.) in a needle-cylinder EHDGS and the initial space charge density. The results showed that the ANN model of nine neurons can well predict the initial space charge density. The coefficient of determination (R2) reaches 0.9874, and the mean absolute error is as low as 0.0067. Subsequently, a hybrid mechanism model where the initial space charge density was predicted from the ANN model was constructed to simulate the needle-cylinder EHDGS. The experiment with the needle-cylinder EHDGS was carried out. The simulation results were in good agreement with the experimental data, demonstrating the reliability of the proposed hybrid model. The electric field distribution, space charge distribution, and flow field distribution behavior of the EHDGS were then analyzed in detail. The effects of key parameters on the flow characteristics of EHDGS were systematically studied, showing that higher voltage and shorter distance give higher flow rate up to 2.5 m/s. The diameter of the cylinder also significantly influences the breakdown voltage. Three dimensionless groups were defined and their effects on spatial charge density distribution were investigated. This study provides both insights and an efficient tool for the design and optimization of EHDGS.

Analyzing the design and performance of a high flow rate digital flow control unit: Structural insights and simulation findings

Analyzing the design and performance of a high flow rate digital flow control unit: Structural insights and simulation findings

A simple guideline for designing droplet microfluidic chips to achieve an improved single (bio)particle encapsulation rate using a stratified flow-assisted particle ordering method

Encapsulation of a single (bio)particle into individual droplets (referred to as single encapsulation) presents tremendous potential for precise biological and chemical reactions at the single (bio)particle level. Previously demonstrated successful strategies often rely on the use of high flow rates, gel, or viscoelastic materials for initial cell ordering prior to encapsulation into droplets, which could potentially challenge the system's operation. We propose to enhance the single encapsulation rate by using a stratified flow structure to focus and pre-order the (bio)particles before encapsulation. The stratified flow structure is formed using two simple aqueous Newtonian fluids with a viscosity contrast, which together serve as the dispersed phase. The single encapsulation rate is influenced by many parameters, including fluid viscosity contrast, geometric conditions, flow conditions and flow rate ratios, and dimensionless numbers such as the capillary number. This study focuses on investigating the influences of these parameters on the focused stream of the stratified flow, which is key for single encapsulation. The results allow the proposal of a simple guideline that can be adopted to design droplet microfluidic chips with an improved single encapsulation rate demanded by a wide range of applications. The guideline was validated by performing the single encapsulation of mouse embryonic stem cells suspended in a gelatin-methacryloyl solution in individual droplets of phosphate buffer saline, achieving a single encapsulation efficiency of up to 70%.

The prospects for the use of alternative gel formers for hydraulic fracturing

The article discusses the relevance of using alternative gel-forming agents in the preparation of fracturing fluids for hydraulic fracturing (HF). Besides the obvious tasks, such as increasing the residual conductivity of the fractures created during stimulation, it also addresses the impact of alternative gelforming agents on the treatment process. The author, supported by field data, concludes that under otherwise equal conditions, replacing traditional fracturing fluids with alternative ones significantly reduces frictional pressure losses in the pipes, which is particularly important when treating deep and extensive horizontal wells with limited internal pipe diameters. Moreover, the aforementioned impact of gel-forming agents on frictional pressure losses allows for a reserve of power in the hydraulic fracturing fleet equipment. Consequently, the treatment can be performed with higher flow rates under otherwise equal conditions, without the need for additional high-pressure pumps or the deployment of more expensive, stronger, larger-diameter tubing. Another important conclusion reached by the author is that due to the specific properties of alternative fracturing fluids, their ability to transport and retain proppant is significantly increased. This property of fracturing fluids is especially important when treating low-permeability, fractured formations and during the stimulation of long horizontal wells. On the other hand, the use of alternative gel-forming agents raises the requirements for the controlled breakdown of fracturing fluids, complicating the task of selecting a rational formulation and necessitating additional research.

CaCl2-Citrate Regional Anticoagulation with Continuous Veno-Venous Haemodialysis Leads to Unwanted Chloride Loading Compared to Continuous Veno-Venous Hemofiltration with Systemic Anticoagulation

Introduction: Chloride transfers during continuous renal replacement therapy (CRRT) have not been adequately described and may differ based on CRRT technique. We aimed to measure chloride mass transfer (JS,Cl) during CRRT and identify associated determinants. Methods: We performed a two-centre, prospective, observational study in France and Australia in ICU patients with CRRT initiated for <24 h. Patients received continuous veno-venous hemofiltration (CVVH) or continuous veno-venous haemodialysis (CVVHD, with citrate-CaCl2 regional anticoagulation). Over a 24 h period, plasma and effluent chloride concentrations were measured every 4 h to compute chloride mass transfer (JS,Cl, in mmol.min-1) using a modality-specific model, with negative value indicating chloride transfer towards the patient. Secondary outcomes were the identification of CRRT settings associated with JS,Cl (using multivariate mixed effects regression). Results are presented with median (interquartile range). Results: Between February 2021 and August 2022, we enrolled 37 patients (64 [56–71] years, 67% male), for a total of 20 CVVHD and 20 CVVH sessions. Over 24 h, plasma chloride concentrations were significantly higher, and JS,Cl significantly lower during CVVHD, compared to CVVH (−0.10 [−0.33 to 0.15] vs. 0.01 [−0.10 to 0.13] mmol.min-1, p < 0.05). With both modalities, net ultrafiltration (QUFNET) and plasma chloride concentrations were the principal determinants of JS,Cl, with higher QUFNET being associated with an increase in JS,Cl during CVVHD. Also, CVVHD sessions demonstrated a concentration gradient between the plasma and the effluent chamber of −6 [−9 to −4] mmol.L-1. Finally, CaCl2 reinjection during CVVHD accounted for 35% [32–60%] of total JS,Cl in sessions with a negative JS,Cl. Conclusion: Compared to CVVH, CVVHD with regional citrate anticoagulation was associated with greater chloride mass transfer to the patient and higher plasma chloride concentrations. This was due to high dialysate chloride concentrations and CaCl2 reinjection. This effect could only be controlled by high net ultrafiltration flow rates.

Prediction of thermal efficiency of double pass solar air heater having discrete multi V and staggered ribs

AbstractThis manuscript endeavors to elucidate a comprehensive analysis for the assessment of thermal efficiency in double pass solar air collectors augmented with fabricated roughness, instrumental in the generation of heated air for applications in heating and drying. The analytical procedure delineates comparisons between a smooth and a double‐sided, roughened absorber, characterized by discrete, multi V and staggered configurations of roughness. The analysis was performed for different roughness parameters including relative roughness width (W/w) from 4 to 8 and relative staggered rib size (r/e) from 1 to 4 and relative rib pitch (p′/p) from 0.2 to 0.8 while other parameters were kept constant. The research scrutinizes the impact of a constellation of parameters: the temperature rise coefficient (ΔT/I, varying between 0.002 and 0.02 K‐m²/W), Reynolds number (Re, spanning 2000–20,000), solar irradiance (I, ranging from 600 to 1000 W/m²), and the geometric variables of the artificial roughness, on both the thermal efficiency and efficiency enhancement factor of the collector. The study revealed that the roughened collector exhibits higher thermal efficiency compared to smooth collector for a similar condition. The extreme enhancement in thermal efficiency of the collector with roughness has been found to be 56.75% more than nonroughened collector for Re = 2000. A further observation was made that thermal efficiency has increased sharply for lower flow rate (Re &lt; 10,000) whereas for higher flow rates (Re &gt; 10,000), this increase becomes nearly asymptotic. In addition, the efficiency enhancement factor has also been found to increase with an increase in ΔT/I. A peak value of 2.321 has been found to be obtained for the efficiency enhancement factor for ΔT/I = 0.02 K‐m2/W and I = 1000 W/m2 as a result of the studies conducted.

Hierarchical Pore Structure Composite Electrode by Electrospinning for Dendrite‐free Zinc‐Based Flow Battery

AbstractIn the pursuit of sustainable energy solutions, zinc‐based flow batteries stand out for their potential in large‐scale energy storage, offering a blend of cost efficiency and safety. Although the porous electrode provides an increased specific surface area for reaction, the non‐uniform deposition of zinc, attributed to uneven concentration distribution within the porous electrode, has been a pivotal issue in accelerating the formation of zinc dendrites, which hinders the enhancement of energy density. A composite electrode with a strategic hierarchical pore structure has been developed with aligned nitrogen‐doped carbon fibers and traditional carbon felt. This structure takes advantage of the large pores of the carbon felt for efficient through‐flow paths, ensuring higher flow rates, while the dual‐scale pores within the electrospun film enhance mass transfer and increase the specific surface area. At 320 mA cm−2, it achieved an ≈11.4% improvement in the battery's energy efficiency. Moreover, the nitrogen doping and the optimized reaction uniformity within the composite electrode have been instrumental in reducing the generation of zinc dendrites. The battery, integrated with the innovative composite electrode, maintained an energy efficiency of 59.2% at 320 mA cm−2 after 300 cycles, which is a substantial improvement in operational longevity.

Suppressing the Memory Effect in Al Doped 3C-SiC Grown Using Chlorinated Chemistry

The memory effect of Al doping in 3C-SiC prevents sharp interfaces between layers of different doping levels and can lead to unintentional doping of subsequent epilayers and even growth runs. Introducing HCl into the growth phase of 3C-SiC reduces the Al incorporation but has a significant impact on Al dopant decay rates and background levels within the chamber, resulting in far sharper doping profiles. The impact of relatively high flow rates of HCl is low within a chlorine-based growth system giving fine control over its influence on the growth process and memory effect.

A column study on Cu (II) adsorption from synthetic solutions using phyto-mineral hybrid adsorbents: RSM optimization, regression modeling and isotherm studies

Abstract Herein we report a novel approach to synthesize hybrid adsorbents using moringa oleifera and zeolite. Three variants were prepared using zeolite mass fractions % of 0.25 %, 0.5 % and 0.75 % respectively. The hybrid adsorbents were investigated for Cu (II) removal from synthetic wastewater using fixed bed column. The lab-scale fixed bed column was designed for Cu (II) removal and optimized using Response Surface Methodology (RSM). The variable parameters included bed height, flow rate, metallic concentration and zeolite mass fraction %. As per results, higher zeolite mass fraction resulted in higher Cu (II) removal. Similarly, the higher bed height increased the removal % of Cu (II). On the other hand, both higher flow rate and metallic concentrations resulted in a declined removal. The highest removal of Cu (II) ions was indicated by hybrid adsorbent with zeolite mass fraction of 0.75 % with 96 % at 1 mL/min flow rate, bed height of 3 cm and metallic concentration of 5 ppm respectively. The maximum adsorption capacities (Qm) indicated by hybrid adsorbents were 19 mg/g (0.25 % Mass Fraction Z), 21.5 mg/g (0.5 % Mass Faction Z) and 24.5 mg/g (0.75 % Mass Fraction Z). The adsorption data best fitted Langmuir Isotherm with R2 value of 0.99 for all variants. When the adsorption data was analyzed using isotherms, data by all three variants best fitted Langmuir isotherm with R2 values of 0.99 for all the variants. Conclusively, higher mass fraction % of zeolite enhanced the removal capacity of Phyto-mineral hybrid adsorbents for Cu (II), whereas higher flow rates and metal concentrations resulted in a declined adsorption of the respective metal ions.