Mixing Rate Research Articles

Effect of Hydrolysis Reactor Design on Maltodextrin Production

Maltodextrin is a short-chain polysaccharide compound resulting from the hydrolysis of starch, which is easily soluble in water, so it has very wide applications for food and health. The production of maltodextrin uses the method of reaction of starch hydrolysis with enzymes carried out using fermenters. The temperature used in the fermenter is 95 °C with a residence time of about 12 hours to reduce the risk of failure in the enzymatic reaction. The stirrer used is a turbine with 6 flat blades. The selection of this type because it has an excellent mixing rate, especially for microscale products. The enzymes that react are alpha-amylase at the liquification stage, and the glucoamylase at the saccharification stage. The yield of maltodextrin is 95% and 5% is the remaining water produced based on the starch hydrolysis process that occurs in the fermenter.

Design and optimization of an onboard boil-off gas re-liquefaction process under different weather-related scenarios with machine learning predictions

In this study, a novel boil-off-gas handling process was proposed to optimize refrigerant mix and flow rate considering different boil-off gas rates under different weather conditions. The proposed design utilizes a nitrogen expander and mixed refrigerant cycle to generate subcooled liquified natural gas to cool the tank, preventing boil-off gas generation. The optimized design in terms of exergy destruction minimization is assessed in a multiple steady-state simulation based on seasonal boil-off gas and heat ingress rates which are predicted by a machine learning algorithm. Furthermore, an economic analysis of the proposed reliquefaction processes was conducted. The result shows that the conventional process has 46% and 8% lower exergy destruction compared to the proposed one for the nitrogen expander and mixed refrigerant cycle respectively. However, the proposed process outperforms the conventional process in terms of investment costs. The proposed process has 36% and 27% lower investment costs for the nitrogen and mixed refrigerant cycle compared to the conventional one. This leads to higher profit for the novel process and performs better in the face of uncertainty of liquified natural gas price.

Man vs. machine: Automated bioink mixing device improves reliability and reproducibility of bioprinting results compared to human operators

The bioink mixing process is highly relevant to the bioink quality, which is the basis for reproducible extrusion-based three-dimensional (3D) bioprinting (EBB). Currently, most bioinks mixed by skilled human operators show variations in terms of cell homogeneity and biological properties as well as other properties. For preparation of many types of bioinks, striking the balance between homogeneity and cell viability remains a major challenge. This study investigates the relationship between bioink homogeneity and mixing parameters, particularly mixing speed and number of exchanges, utilizing a customized automated device. We found that up to a certain point, increasing the rate of mixing led to a better distribution of cells within the bioink, but beyond that point, there was a detrimental effect on cell viability. In contrast, the mixing number had less impact on the physiological properties of the cells in the bioink. Furthermore, a comparison between skilled human and machine bioink mixing revealed that the machine consistently provided better outcomes in terms of bioink homogeneity, cell distribution, and cell viability, highlighting the advantages and importance of standardizing the bioink mixing process. The methodology and approaches in this study can improve the reproducibility and reliability of EBB bioink and may thereby advance the field of 3D bioprinting in various applications.

Chalcopyrite Leaching in the Presence of Isopropanol-The Kinetic and Mechanistic Studies.

Oxidative leaching, as a basic step of the hydrometallurgical process of pure copper production from chalcopyrite, is a slow process in which mineral acids with strong oxidants addition are usually used as a leaching medium. It was found experimentally that the copper leaching from chalcopyrite in the H2SO4-H2O2-H2O system, in the presence of isopropanol (IPA) and under other conditions (H2O2 concentration, rate of mixing and temperature), takes place with satisfactory rate and efficiency. To quantify how much the change of these crucial variables affects the rate of the process, experimentally obtained kinetic curves (conversion over time) were analyzed using a Shrinking Core Model (SCM). The determined values of the copper leaching rate constants (kobs) confirmed the positive influence of increasing IPA and H2O2 concentrations as well as the temperature on the kinetics and efficiency of the leaching. The kinetic studies were also supported by using X-ray diffraction (XRD), 57Fe Mössbauer spectroscopy, scanning electron microscopy (SEM), and adsorption measurements. The positive influence of IPA was explained by its stabilizing role for iron compounds (hematite, magnetite, and pyrite), which are catalysts during the Cu dissolution, as well as H2O2 protection from decomposition during free radical reactions. Finally, the optimal conditions for efficient leaching, the rate-limiting step as well as the mechanism suggestion of the copper dissolution, were given.

Quantifying the turbulent mixing driven by the Faraday instability in rotating miscible fluids

The effect of the rotation on the turbulent mixing of two miscible fluids of small contrasting density, induced by Faraday instability, is investigated using direct numerical simulations. We quantify the irreversible mixing, which depicts the conversion of the available potential energy (APE) to the background potential energy (BPE) through the irreversible mixing rate M. We demonstrate that at lower forcing amplitudes, the turbulent kinetic energy (t.k.e.) increases with an increase in the Coriolis frequency f till (f/ω)2<0.25, where ω is the forcing frequency, during the sub-harmonic instability phase. This enhancement of t.k.e. is attributed to the excitement of more unstable modes. The irreversible mixing sustains for an extended period with increasing (f/ω)2 till 0.25 owing to the prolonged sub-harmonic instability phase and eventually ceases with instability saturation. When (f/ω)2>0.25, the Coriolis force significantly delays the onset of the sub-harmonic instabilities. The strong rotational effects result in lower turbulence because the bulk of the APE expends to BPE, decreasing APE that converts back to t.k.e. reservoir for (f/ω)2>0.25. Therefore, in the subsequent oscillation, the t.k.e. available to contribute to the external energy input from periodic forcing is small. Since the instability never saturates for (f/ω)2>0.25, the conversion of APE to BPE via M continues, and we find prolonged irreversible mixing. At higher forcing amplitudes, the instability delaying effect of rotation is negligible, and the turbulence is less intense and short-lived. Therefore, the irreversible mixing phenomenon also ends quickly for (f/ω)2<0.25. However, when (f/ω)2>0.25, a continuous irreversible mixing is observed. We also examine the mixing efficiency in terms of M and find that the mixing is efficient at lower forcing amplitudes and rotation rates of (f/ω)2>0.25 because the major portion of APE expends to BPE.

Nonlinear Landau resonant interaction between whistler waves and electrons: Excitation of electron-acoustic waves

Electron-acoustic waves (EAWs) as well as electron-acoustic solitary structures play a crucial role in thermalization and acceleration of electron populations in Earth's magnetosphere. These waves are often observed in association with whistler-mode waves, but the detailed mechanism of EAW and whistler wave coupling is not yet revealed. We investigate the excitation mechanism of EAWs and their potential relation to whistler waves using particle-in-cell simulations. Whistler waves are first excited by electrons with a temperature anisotropy perpendicular to the background magnetic field. Electrons trapped by these whistler waves through nonlinear Landau resonance form localized field-aligned beams, which subsequently excite EAWs. By comparing the growth rate of EAWs and the phase mixing rate of trapped electron beams, we obtain the critical condition for EAW excitation, which is consistent with our simulation results across a wide region in parameter space. These results are expected to be useful in the interpretation of concurrent observations of whistler-mode waves and nonlinear solitary structures and may also have important implications for investigation of cross-scale energy transfer in the near-Earth space environment.

Mixing of Rain and River Water in the Bay of Bengal From Basin‐Scale Freshwater Balance

AbstractWe construct freshwater balance in the Bay of Bengal (BoB) within a control volume (CV) bounded by 1,018 kg/m3 isopycnal surface using observations and ocean reanalysis during 2011–2015. Freshwater in CV is maximum in October–November due to monsoonal rain and river inflows, and minimum in April–May. Water lighter than 1,018 kg/m3 is not transported out of BoB, implying that freshwater lost from CV is mixed away entirely within the basin. From freshwater budget, we infer moderate diapycnal mixing rates (∼0.8 × 10−5 m2/s) in boreal spring and summer; in winter (December–January), the rate of freshwater loss to subsurface ocean is 0.015 m/day, corresponding to a median turbulent diffusivity of 4.2 × 10−5 m2/s, with standard error of 25%. We show that enhanced winter mixing across the shallow pycnocline is due to reduced shortwave radiation and subseasonal episodes of surface buoyancy loss when cool, dry northeast monsoon winds blow over BoB.

Experimental and cfd analysis of the influence of fuel injection timing on the behavior of a gasohol-based gdi engine

ABSTRACT This work examines the impact of FIT (Fuel Injection Timing) on engine’s performance of an automotive, Gasoline Direct Injection (GDI) engine using Gasohol (85% Gasoline + 15% Ethanol by mass) as fuel. The start of FIT was experimentally varied from −280 CAD (Crank Angle Degrees) to −330 CAD at 10 CAD intervals by using an open ECU. Experiments were performed at variable power outputs (such as 5, 8, 10, 13, 16, 18 and 21 kW) at a constant speed of 2500 rpm. CFD simulations were carried out for the above said conditions to understand engine’s behavior. Considering the conventional start of injection, advancing the FIT showed improvement the BTE (brake thermal efficiency) up to −320 CAD BTDC. The maximum BTE was observed as 31.8% at the engine power output of 21 kW (whereas it was 28.6% at −300°CAD). CFD results confirmed the improvement in the air-fuel mixing rate and swirl motion. With the use of advanced FITs, the emissions of carbon monoxide (CO) and hydrocarbons (HC) were decreased. The CFD emission results for CO and HC showed good agreement with the experimental findings. With the advanced FITs, NOx emissions showed an increase at all loads. The in cylinder pressure was observed to be higher with advanced FITs. Modeling results are very well supported with experimental pressures. It is concluded that advancing the fuel injection timing might improve the performance and lower HC and CO emissions of a Gasohol-based GDI engine. The optimized injection timing of −320 CAD could be recommended for the aforementioned engine’s greatest performance.

Effect of lignin on coal slime combustion characteristics and carbon dioxide emission

The escalating total amount of industrial solid waste is increasingly taxing the ecological environment. Co-combustion technology is seen as a potential solution to this problem. This study investigated the interaction mechanism and carbon dioxide emissions during the co-combustion process of coal slime and biomass (lignin) using a programmed heating method. The experimental results reveal that the two sub-reaction models effectively depict the combustion process of coal slime. In the co-combustion process, the comprehensive combustion and ignition performance of the mixed fuels surpasses that of coal slime, but the stability of the combustion flame is reduced. The combustion performance of the mixed fuel is primarily influenced by two common factors. The interaction between lignin and coal slime significantly changes with the variation of mixing ratio and heating rate. The main product in the combustion process of mixed fuels is carbon dioxide. Due to the competition for oxygen among volatile matter, the emission of carbon dioxide is lower than the theoretical value. When the mass percentage of lignin is 70 %, the impact on carbon dioxide is most pronounced. The experimental results of this study provide a foundation for understanding the interaction mechanism of coal slime and biomass co-combustion. The research findings also provide theoretical guidance for the safe operation of coal slime and biomass co-combustion equipment.

Investigation of TiO2 replacement alternatives for water-based paints using styrene butyl acrylate

Purpose Titanium dioxide (TiO2) has high opacity, high brightness and whiteness, owing to its high refractive index value. It is mainly used in the coating industry and continuous efforts have been made to replace some of the TiO2 in paint with new pigments. This study aims to replace part of TiO2 pigment with various percentages of BaSO4, CaCO3 and kaolin in styrene butyl acrylate-based paint formulations, without changing the properties of paints using only titanium dioxide. Design/methodology/approach To determine the optimum use rate of new pigment mixing, opacity, gloss, scrub resistance and weather resistance properties have been investigated in the water-based paint formulation. The morphological properties of these samples were examined by scanning electron microscopy analysis. Findings In the total color change (ΔE) measurements, it was observed that the sample coded 85Ti/15Ba produced extremely similar results to the situation when TiO2 was used alone. It was seen that the best results were obtained when 85Ti/15Ba was used instead of TiO2. Originality/value Comparison research on the impact of replacing TiO2 with BaSO4, CaCO3 and kaolin on the performance characteristics of water-based styrene butyl acrylate-based paint formulations has not been done in the literature, according to the literature search.

Hydrothermal performance and entropy production rate of rGO-CO3O4/H2O hybrid nanofluid in corrugated-converging pipes

The ever-growing interest in developing more effective and compact heat exchangers necessitates the investigation of combined passive solutions. Despite the diverse related literature, there are no studies on corrugated-converging pipes. This work examines the effect of Reynold's number (5.0×103≤Re≤5.0×104), diameter ratio (1≤DR≤2), and concentration of nanoparticle (0≤VR≤0.2%), on the Poiseuille number (fRe), average Nusselt number (Nu), performance evaluation criterion (PEC), and EPR of rGO−CO3O4/ H2O hybrid nanofluid (NF) flowing in corrugated-converging pipes of different orientations (inwardly and outwardly) and smooth converging pipes in turbulent flow regime. The k−ω and discrete phase models were used to simulate the turbulent hybrid NF flow by Ansys Fluent. The results revealed that the Nu in the corrugated converging pipe is higher than that of a smooth pipe, but this is accompanied by a higher pressure drop (dP). The argumentation of Nu is attributed to flow acceleration, thinning of the thermal boundary layer (TBL), and an increase in the rate of mixing as a result of the relative increase in turbulence introduced by the presence of corrugation. In addition, it was noted that the modified pipes have lower EPR due to temperature gradient (TEPR) compared with straight pipe. However, the opposite is the case for EPR due to fluid flow (VEPR). The lower TEPR and higher VEPR are attributed to a relative increase in flow turbulence. Quantitatively, the normalized values (referencing smooth pipe) of Nu, (fRe), TEPR, and VEPR at Re=5×103 in inwardly and outwardly corrugated converging pipes and smooth converging pipes of DR = 2 are {2.24, 8.15×101, 4.13×10−1, and 8.62×101}, {1.94, 4.45×101, 4.78×10−1, and 4.15×101} and {1.03, 3.1×101,9.20×10−1, and 3.17×101}, respectively. PEC increases with increasing VR. For instance, across the range of VR considered (0 % ≤ VR ≤ 0.2 %), the values of PEC increase by 20.69 %. Consequently, it can be presented as a promising heat transfer enhancement technique in terms of energy saving. Consequently, corrugated-converging pipes can be presented as a promising heat transfer enhancement technique in terms of energy saving.

Impact of Injection Rate on Flow Mixing during the Refining Stage in an Electric Arc Furnace

During the refining stage of electric arc furnace (EAF) operation, molten steel is stirred to facilitate gas/steel/slag reactions and the removal of impurities, which determines the quality of the steel. The stirring process can be driven by the injection of oxygen, which is carried out by burners operating in lance mode. In this study, a computational fluid dynamics (CFD) platform is used to simulate the liquid steel flow dynamics in an industrial-scale scrap-based EAF. The CFD platform simulates the three-dimensional, transient, non-reacting flow of the liquid steel bath stirred by oxygen injection to analyze the mixing process. In particular, the CFD study simulates liquid steel flow in an industrial-scale EAF with three asymmetric coherent jets, which impacts the liquid steel mixing under different injection conditions. The liquid steel mixing is quantified by defining two variables: the mixing time and the standard deviation of the flow velocity. The results indicate that the mixing rate of the bath is determined by flow dynamics near the injection cavities and that the formation of very low-velocity regions or ‘dead zones’ at the center of the furnace and the balcony regions prevents flow mixing. This study includes a baseline case, where oxygen is injected at 1000 SCFM in all the burners. Two sets of cases are also included: The first set considers cases where oxygen is injected at a reduced and at an increased uniform flow rate, 750 and 1250 SCFM, respectively. The second set considers cases with non-uniform injection rates in each burner, which keep the same total flow rate of the baseline case, 3000 SCFM. Comparison between the two sets of simulations against the baseline case shows that by increasing the uniform flow rate from 1000 to 1250 SCFM, the mixing time is reduced by 10.9%. Moreover, all the non-uniform injection cases reduce the mixing time obtained in the baseline case. However, the reduction in mixing times in these cases is accompanied by an increase in the standard deviations of the flow field. Among the non-uniform injection cases, the largest reduction in mixing time compared to the baseline case is 10.2%, which is obtained when the largest flow rates are assigned to coherent jets located opposite each other across the furnace.

Ignition Probability of Turbulent Non-Premixed Swirling Flames in a Double-Swirl Burner

ABSTRACT In this paper, the effect of swirl number on mixing structure and ignition probability in turbulent non-premixed natural gas/air flame has been investigated. The flames are visualized by a digital camera and inverted by Abel’s transformation. Maps of ignition probability are generated by changing the spark position axially and radially while the flow field and mixing topology are established using numerical simulation. Three zones were defined based on the probability of successful ignition. The first one was the ineffective zone where the probability of a successful ignition was less than 20%. The second one was called the transition zone where the probability of a successful ignition was between 20% and 80%, and a successful ignition was highly dependent on the spark location. The third one was called the high-probability zone where the probability of a successful ignition was more than 80%. It was found that although the increment in swirl number improves the rate of mixing, it does not result in a better distribution of successful ignition probability. In high swirl numbers, the high-probability region is very small but at lower swirl numbers, the high-probability region is distributed at the burner exit, resulting IN better ignition characteristics.

Optimizing aeration efficiency and forecasting dissolved oxygen in brackish water aquaculture: Insights from paddle wheel aerator

BackgroundAquaculture relies significantly on effective aeration systems to ensure optimal conditions for aquatic organisms. This 96-day study investigates the dynamic relationship between Oxygen Transfer Rates (OTR) and seasonal variations, with a specific focus on the impact of seasonal dynamics and the placement of paddle wheel aerators. The study recognizes the pivotal role of Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) as key water quality parameters influencing aeration efficiency. MethodologyA series of water circulation experiments were conducted at regular intervals to assess mixing rates, revealing a nuanced trajectory ranging from 27.05 to 14.22 m³/kWh. The study scrutinized the influence of TDS and TSS on these rates. Additionally, water velocity variations, ranging from 0.45 to 1.67 m/s, were examined, highlighting density-dependent changes, particularly evident post four weeks of operation. Oxygen stratification analysis provided insights into deviations in Dissolved Oxygen (DO) concentrations, with particular attention to climatic aberrations. Rigorous statistical analyses, including chi-squared, Pearson correlation, Gaussian distribution checks, and student's t-tests, validated the methodological robustness and data reliability. Significant findingsEmploying a Seasonal Auto Regressive Integrated Moving Average (SARIMA) model, the study achieved a remarkable 97 % accuracy in forecasting DO levels for the subsequent 96 days. Real-time validation, complemented by a Chi-square goodness of fit test, reaffirmed the model's reliability, establishing congruence between observed and forecasted values. This research underscores the critical roles of strategic aerator placement and seasonal considerations in optimizing pond aeration efficiency, providing substantive insights for the sustainable management of aquaculture ecosystems.

Orthogonal Experimental Study on the Ratio of Similar Materials of Coal Body

According to the coal samples collected from Zhaogu No.2 Coal Mine as raw coal samples, the similar materials of coal body were studied by using river sand, pulverized coal, Portland cement and calcium carbonate. The orthogonal test method of four factors (bone glue ratio, aggregate ratio, rubber ratio, water mixing rate) and three levels was used to obtain the physical and mechanical parameters such as density, uniaxial compressive strength, elastic modulus, cohesion, internal friction angle and tensile strength of coal similar materials. The range analysis method was used to obtain the key influencing factors and variation rules of the physical and mechanical properties of coal similar materials. Finally, the method of multiple linear regression analysis was used to obtain the similar material ratio that was most consistent with the mechanical properties index of raw coal. The ratio of calcium carbonate: cement: river sand: coal powder: water = 1: 5: 0.9: 5.9: 3.2. The density error, compressive strength error, elastic modulus error and cohesion error of coal sample and raw coal are small, which proves that the similar material is similar to the mechanical properties of raw coal, and provides guidance for subsequent research.

Changes in Spectrum of Respiratory Pathogen Infections and Disease Severity Among Children in Hohhot, China: Impact of COVID-19 Prevention Measures.

BACKGROUND This retrospective study evaluated the effects of specific COVID-19 preventive measures, including the use of medical masks, nucleic acid testing, and patient isolation, on respiratory infections, disease severity, and seasonal patterns among children in Hohhot, located in northern China. Understanding these alterations is pivotal in developing effective strategies to handle pediatric respiratory infections within the context of continuous public health initiatives. MATERIAL AND METHODS At the First Hospital of Hohhot, throat swabs were collected from 605 children with community-acquired respiratory between January 2022 and March 2023 for pathogen infection spectrum detection using microarray testing. RESULTS Among the patients, 56.03% were male, and their average age was 3.45 years. SARS-CoV-2 infections were highest between October 2022 and January 2023. Influenza A peaked in March 2023, and other pathogens such as respiratory syncytial virus and influenza B virus disappeared after December 2022. The proportion of mixed infections was 41.94% among SARS-CoV-2 patients, while other pathogens had mixed infection rates exceeding 57.14%. Before December 2022, the mean WBC count for Streptococcus pneumoniae and Haemophilus influenzae was 8.83×10⁹/L, CRP was 18.36 mg/L, and PCT was 1.11 ng/ml. After December 2022, these values decreased significantly. Coughing, difficulty breathing, running nose, and lower respiratory tract infection diagnoses decreased in December 2022, except for SARS-CoV-2 infections. CONCLUSIONS SARS-CoV-2 peaked around November 2022, influenza A peaked in March 2023, and other pathogens like respiratory syncytial virus and influenza B virus were greatly reduced after December 2022. Inflammatory markers and respiratory symptoms decreased after December 2022, except for SARS-CoV-2.

Impact of Autonomous Vehicles on Traffic Flow in Rural and Urban Areas Using a Traffic Flow Simulator

Autonomous vehicles have the potential to significantly improve modes of transportation, and many businesses and research facilities are developing such systems. Although there are studies on the social implementation of autonomous vehicles, these studies are based on limited conditions such as predetermined driving environments. Therefore, in this study, we target urban areas and rural areas, and we simulate a behavioral algorithm for autonomous vehicles being developed and owned by Kanazawa University. In this study, a traffic flow simulation system (Aimsun) was constructed to reproduce the current situation of traffic flow in the city during normal times, using data from a person-trip survey conducted by the local government. In addition, we varied the mixing rate of automated vehicles and evaluated its effect on the delay time between ODs. We assume the gradual replacement of existing vehicles by autonomous vehicles on actual road networks and for realistic traffic volumes, and we investigate their impact on traffic flow. We vary the mixing rate of autonomous vehicles into actual traffic environments, and we measure the delay in the origin-destination (OD) interval to evaluate the impact of autonomous vehicles on traffic flow. The results obtained show that as the mixing rate of autonomous vehicles increases, the delay between OD intervals increases. Then, once the mixing rate exceeds a certain value, the delay between OD intervals gradually decreased. The delay time for all vehicles slightly increases as the mixing rate of autonomous vehicles increased from 10 to 45%. When the mixing rate increased from 45 to 50%, the delay time for all vehicles decreased notably, and when the mixing rate was 50 to 100%, it remained constant. Analytical results showed that when socially implementing autonomous vehicles, their mixing rate impacts the traffic flow; thus, there is a need to determine appropriate distribution scenarios and areas for implementation.

Turbulent mixing in the vertical magnetic Rayleigh–Taylor instability

The presence of a mean magnetic field aligned with the direction of the acceleration greatly modifies the development of the Rayleigh–Taylor instability (RTI). High resolution direct numerical simulations of the Boussinesq–Navier–Stokes equations under the magnetohydrodynamics approximation reveal that, after an initial damping of the perturbations at the interface between the two miscible fluids, a rapid increase of the mixing layer is observed. Structures are significantly stretched in the vertical direction because magnetic tension prevents small-scale shear instabilities. When the vertical turbulent velocity exceeds the Alfvén velocity, the flow transitions to turbulence, structures break and an enhanced mixing occurs with strong dissipation. Afterwards, the mixing zone slows down and its growth rate is decreased compared to the hydrodynamic case. For larger magnitudes of the mean magnetic field, a strong anisotropy persists, and an increased fraction of potential energy injected into the system is lost into turbulent magnetic energy: as a consequence, the mixing zone growth rate is decreased even more. This phenomenology is embedded in a general buoyancy-drag equation, derived from simplified equations that reflect the large-scale dynamics, in which the drag coefficient is increased by the presence of turbulent magnetic energy.

Lane management for mixed traffic flow on roadways considering the car-following behaviors of human-driven vehicles to follow connected and automated vehicles

The widespread adoption of emerging connected and automated vehicles (CAVs) highlights the need for identifying the roadway capacity of mixed traffic flow with CAVs and human-driven vehicles (HDVs) for future traffic management. Previous studies focus on analyzing the impacts of CAV technologies on the mixed traffic capacity. However, research on how different car-following behaviors of HDVs to follow CAVs affect the mixed traffic capacity is still lacking. This study proposes an analytical formulation of the mixed traffic capacity based on the probability distributions of HDVs and CAVs and three types of behavior willingness (i.e., believer, neutral, and skeptic) of HDV-following-CAV in a mixed traffic environment. The sufficient conditions are derived for mixed traffic capacity to increase or decrease with the behavior willingness and CAV penetration rate. Based on that, an analytical lane management (LM) model is further proposed to determine the optimal number of CAV dedicated lanes (CDLs) and CAV non-dedicated lane (CNL) strategies that maximize the mixed traffic throughput, considering the mixed traffic demand, behavior willingness, and CAV penetration rate. The results from numerical experiments show that the proposed LM strategies can significantly improve mixed traffic throughputs by deploying optimal CDLs and CNL strategies, compared to one without the LM strategy. The mixed traffic throughputs improve and reduce as the trust willingness and skeptic willingness increase and decrease, respectively. Moreover, the increment in CAV penetration rate does not certainly correspond to the high mixed traffic throughputs. The behavior willingness and heterogeneous headways could be jointly considered to guarantee the positive influences of CAV penetration rate on the mixed traffic throughputs when implementing the LM strategy for the mixed traffic flow.

Smart scale-up of micromixers for efficient continuous biodiesel synthesis: A numerical study for process intensification

This study focuses on developing continuous processes for biodiesel synthesis, overcoming limitations of conventional batch reactions, such as biphasic reaction and thermodynamic equilibrium, and reducing production costs. While microreactors are promising for enhancing mixing and transfer rates at smaller scales, scaling up to larger channels results in decreased efficiency and product yield. Microfluidic devices, useful in continuous biodiesel production, lose mixing efficiency when scaled up, affecting product yield. The present study proposes a novel microreactor design with static elements, aiming to improve fluid mixing and reaction performance at higher volumes. The smart scale-up strategy includes an optimized micromixer design, enlarged channel cross-sectional area, and an additional obstacle-free channel. Using a Fractional Design followed by a Central Compound Rotational Design, optimal values for key design variables are identified. Computational tests show a high mixing index (M > 0.77) across a wide range of Reynolds numbers (Re = 0.1–100). Numerical simulations under optimal conditions indicate high conversions (>91 %) for residence times above 60 s. This design promises advancements in industrial-scale biodiesel production, with improved flow and reactant distribution, potentially reducing the number of micro/millidevices needed.