Pressure Flow Research Articles

SEMI-BATCH EXPERIMENTAL STUDY ON MULTIPLE CARBON DIOXIDE BUBBLES ABSORPTION IN SWEETENER SOLUTION UNDER VARYING PRESSURES

Increasing the absorbed carbon dioxide amount in sweetener solution is a new trend to modify soft drinks. This research investigated the optimum increase in absorbed carbon dioxide within the limits of permissible food specifications in the bubble column. Response surface methodology (RSM) utilizing the Box Behnken design (BBD) was used to conduct experiments operating conditions for achieving desired responses within specified ranges of pressure (2-4 bar), temperature (5-25°C), gas flow rate (0.2–0.4 L/min), and absorbent concentration (0–150 g/L). The experimentally obtained results were fitted to a second-order polynomial model—the increase in pressure and gas flow rate results in an increase in absorption yield (YCO2). Also, increasing the gas flow rate and temperature will increase the volumetric mass transfer coefficient (KLa), while, at high pressure and pore size KLa will be reduced. According to the obtained results at optimum conditions, 4 bar, 5°C, gas flow rate 0.4 L/min, sucrose concentration of 0 g/L, and pore diffuser 0.5 μm; The CO2 content (YCO2) was 8.34 g/L. The optimum conditions for combining the effect of high CO2 content (6.125 g/L) and best KLa value (0.1043 L/min) were: 2.83 bar, 5 °C, a gas flow rate of 0.4 L/min, a sucrose concentration of 65.15 g/L, and pore diffuser of 0.5 μm.

Cold Pressor Test Induces Significant Changes in Internal Jugular Vein Flow Dynamics in Healthy Young Adults.

BACKGROUND The cold pressor test (CPT), which has long been used to test autonomic functions by causing sympathetic excitation, increases systolic and diastolic blood pressure and heart rate and causes coronary vasodilation within physiological limits in healthy individuals. This study aimed to evaluate internal jugular vein (IJV) flow parameters using the CPT with systolic and diastolic blood pressure and heart rate in 40 healthy volunteers aged 18-40 years. MATERIAL AND METHODS The volunteers' IJV diameter, blood flow peak velocity, and volumetric flow values were recorded. Then, their right hands were immersed in a bucket of cold water maintained at 1°C up to the wrist level. At the end of the first minute (CPT-1), systolic and diastolic blood pressure, heart rhythm, IJV diameter, peak velocity, and volumetric flow measurements were performed again. RESULTS Systolic and diastolic blood pressure values were significantly higher at CPT-1 compared to baseline values (P<0.001, P<0.001). Heart rate and peak velocity values also showed a significant increase at CPT-1 compared to baseline values (P<0.001, P=0.001). While diameter values showed a significant decrease compared to baseline, volumetric flow rate values showed a significant increase at CPT-1 (P=0.003, P<0.001). CONCLUSIONS Sympathetic nervous system activation triggered by CPT increases IJV volumetric flow and flow velocity in healthy young individuals, and sympathetic nervous system activation causes a venoconstrictive effect in the IJV.

Operational characteristics and performance optimizations of the organic Rankine cycle under different heat source/condensing environment conditions

The fluctuating heat sources and seasonal condensing environments are critical to the operation of Organic Rankine Cycle (ORC) under off-design conditions. This paper presents a comprehensive steady-state mathematical model developed using a newly built experimental platform. Focusing on the operational characteristics, including the evaporation pressure, condensation temperature, mass flow rate, and the performance of key equipment during the regulation of the expander, working fluid pump, and cooling water pump. Results show that the net efficiency initially increases before decreases, with both evaporation pressure and mass flow rate rising alongside the working fluid pump frequency. The quasi-two-stage single screw expander achieves an isentropic efficiency above 65 %. Additionally, flexible adjustments to the cooling water pump effectively regulate the cooling system, with timely cleaning of cooling pipelines enhancing net efficiency by up to 3.27 %. Optimization using the particle swarm algorithm improves system performance, achieving net efficiency enhancements of 1.8 % and 12.3 % under specific conditions. The novelty of this study lies in directly regulation of the expander, working fluid pump, and cooling water pump, significantly enhancing the off-design performance. This research provides valuable insights for researchers and designers, enabling flexible regulation of ORC operations to ensure efficient performance under varying conditions.

Experimental study on flow patterns and pressure gradient of decaying swirling gas-liquid flow in a horizontal pipe

The utilization of swirling flow in multiphase flow devices is prevalent for purposes such as mixing, separation, stabilization, and heat transfer enhancement, primarily owing to its characteristic of inducing low-pressure drop. In the nuclear industry, for example, two-phase swirling flow is applied in the nuclear gas generator to improve gas quality. In this study, an experimental investigation was conducted on the decaying swirling flow of gas-liquid in a horizontal pipe equipped with a vane-type swirler. The flow patterns were visually examined, and the pressure gradients along the test pipe and across the swirler were measured. The findings suggest the presence of four distinct swirling flow patterns at the swirler outlet (z/D = 0), namely chain flow, swirling gas column flow, swirling intermittent flow, and swirling annular flow. Because of swirl decay, these swirling flows recover their original pattern approximately 70D downstream from the swirler, with the exception of the swirling gas column flow. The flow regime maps at z/D = 10, 40, 70 and 100 are proposed and the pattern-based pressure gradient characteristics are analyzed. It is shown that the pressure gradient rises as both gas superficial velocity (jg) and liquid superficial velocity (jl) increase. The largest pressure gradient occurs within the swirler section, while the lowest is found upstream of the swirler. Near the swirler outlet (z/D = 0–33), the pressure gradient is approximately 1.5–2.3 times higher than at z/D = 33–67. Further downstream, at z/D = 67–100, it is 2.2–3.5 times greater, depending on the flow patterns.

Positional Effects of a Fly’s Wing Vein in the Asymmetric Distribution of Hydraulic Resistances

Insect wing vein networks facilitate blood transport with unknown haemodynamic effects on their structures. Fruit flies have the posterior cross vein (PCV) that disrupts the symmetry of the network topology and reduces the total pressure loss during blood transport; however, the impact of its various positions among species has not been examined. This study investigated the haemodynamic effects of this vein with various connecting positions. By analogising venous networks to hydraulic circuits, the flow rates and pressure losses within the veins were derived using Poiseuille’s and Kirchhoff’s laws. The results showed that the total pressure loss decreased for both PCV connections near the wing’s base. In an idealised circuit imitating the network topology, applied high hydraulic resistances as one-sided as those along the edge of the wing, the same pressure loss response as that in the actual network was demonstrated, but not within a symmetric resistance distribution. Therefore, the most proximal PCV minimises the pressure loss within the asymmetric resistance distribution, indicating an evolutionary adaptation to reducing the pressure loss in certain species with this vein near the base. Our findings highlight the possible optimisation of the flies’ wing morphology to maintain the functions of the liquid transport networks and flight devices simultaneously.

A Study on Two-Phase Flow with High Viscosity and Low Surface Tension Liquid in a 40-Degree Inclined Mini Channel

There are numerous applications of two-phase flow in mini pipes, including electronics cooling systems, microreactors in the chemical industry, and material development and manufacturing. This application requires a thorough understanding and is supported by complete data and information. However, the data and information are currently limited. Experimental research has been carried out on flow patterns, void fractions, and two-phase flow pressure gradients in small pipes. This study aims to obtain primary data on the subject. Dry air and a mixture of 67% distilled water, 30% glycerin, and 3% butanol represent the gas and liquid phases, respectively. The addition of butanol and glycerin each aims to reduce surface tension and improve the viscosity of the liquid phase, respectively. The density, kinematic viscosity, and surface tension of the liquid were 1,080.4 kg/m3, 2,368 mm2/s, and 38.6 mN/m, respectively. The test section was a 1.6 mm diameter glass pipe equipped with an optical correction box. The gas superficial velocity (JG) ranged from 0.025 to 66.3 m/s, whereas liquid superficial velocity (JL) varied from 0.033 to 4.935 m/s. The experiment was conducted under adiabatic conditions. Plug, slug-annular, annular, disperse bubbly, and churn flow patterns emerged, while separated flow was not discovered. For plug, slug-annular, and dispersed bubbly flows, the increase of JG proportionally affected the void fraction. However, for churn and annular flows, no particular relationship existed between JG and void fraction due to the slip between the real velocities of the gas and the liquid. The pressure gradient rose as JG and JL increased.

Hydrogen storage and refueling options: A performance evaluation

This study focuses on the comparative modeling and refueling simulations of hydrogen refueling stations for hydrogen-powered vehicles and high-pressure hydrogen storage options in tanks. The study further aims to simulate these under actual conditions in Ontario, Canada for better assessment which can be treated as a case study as well. The specific tests explore the modeling of hydrogen flow between the recharging station to the car's tank, as well as the optimization of transient variations in temperature, pressure and mass flow rate of hydrogen throughout the process of refueling a fuel cell electric vehicle. The H2FILLS program is utilized to assist for the simulation studies. The primary objective is to replicate various practical weather conditions, tank pressures, flow rates, and refueling periods for different categories of high-pressure hydrogen storage tanks and analyze their storage efficiency. The three different commercially available high-pressure type-IV hydrogen storage tanks were considered in the study as tank-I, tank-II and tank-III with working pressures of 500 bar, 700 bar, 700 bar, and hydrogen storage capacity of 9.5 kg, 4.6 kg, and 5 kg, respectively. Seven different ambient temperatures were selected to mimic seasonal effects. When the power output is constant, with temperature increases, flow rate decreases, and therefore time required to refuel also increases. There is a linear relationship between the final mass flow rate and the ambient temperature, where the mass flow rate drops by approximately 1.8 kg/h for every 10 °C rise in temperature. The variation in ultimate mass flow rate between the highest and lowest ambient temperatures is roughly 5.4 kg/h. Based on the refueling time and docking, undocking, downtime it’s been found that approximately five minutes is wasted between each vehicle. This can help reduce average of 230.02 kt, 231.70 kt, and 235.06 kt CO2 emission per year for vehicle-III, vehicle-II, and vehicle-I, respectively. Lastly, yearly CO2 reduction forecast shows that it may reach 0.9 Mt, 1.6 Mt, 2.7Mt, 3.76 Mt, and 4.73 Mt in the year 2030, 2035, 2040, 2045, and 2050, respectively corresponding to the Global Net-Zero scenario.

Dynamic simulation and optimal design of a combined cold and power system with 10 MW compressed air energy storage and integrated refrigeration

A combined cold and power system with 10 MW compressed air energy storage and integrated refrigeration (CCR) is proposed. In traditional 10 MW compressed air energy storage (CAES) system, outlet pressure of air tank is throttled to a low pressure by throttling device. In CCR system, the throttling device is replaced by a piston turbine to achieve control of pressure and mass flow. Meanwhile, pressure potential energy of compressed air is converted to mechanical work, which is used to drive refrigeration subsystem. The dynamic mathematic model of proposed CCR system is built up. According to energy and exergy analysis of the whole dynamic process, it is confirmed that the proposed model obeys the first and second laws of thermodynamics. The optimal solution for T23 and γAC are calculated to be 259.6896 K and 1.2335, respectively. The Pareto frontier of multi-objective optimization of energy and exergy efficiencies are conducted. Energy efficiency of proposed CCR system is higher than that of CAES system by at least 32.8 %. The electrical efficiency of proposed CCR system is also higher than that of CAES system. It suggests that the pressure potential energy wasted in the throttle process is well utilized by the piston turbine in CCR system.

The Influence of Pre-Lift Gate Opening on the Internal and External Flow Characteristics During the Startup Process of an Axial Flow Pump

This paper focuses on a vertical axial flow pump and employs a 1D-3D coupling method to investigate the effects of different gate pre-opening angles on the internal and external flow characteristics of the axial flow pump during startup. Through comparative analysis, the following conclusions are drawn: In the study, a fully open gate is defined as 1, while a fully closed gate is defined as 0. When starting the axial flow pump with different valve pre-opening degrees, backflow occurs within the first 20 s of startup, and the backflow rate inside the pump gradually increases with the increase in the valve pre-opening degree. At a valve pre-opening degree of 0.6, the maximum backflow rate inside the pump reaches 5.89% of the rated flow rate. When starting the pump with the valve fully open, the maximum backflow rate reaches 10.98% of the rated flow rate, and the efficiency is affected by the backflow rate. The valve pre-opening degree has little impact on the axial force acting on the impeller during startup. When starting with a valve pre-opening degree of 0.6, the internal pressure difference in the pump is minimized. Within the first 20 s of startup, the internal pressure difference in the impeller is 28.96% higher and the flow velocity is 14.62% higher with valve pre-opening degrees of 0.8 and 1.0 compared to a 0.6 degree opening. During the initial stage of pump startup, with valve pre-opening degrees of 0.8 and 1.0, the pressure fluctuation amplitude inside the pump is minimal, with maximum relative amplitudes of only 0.621 and 0.525, which are 41.00% and 28.51% lower than the maximum amplitudes at 0 and 0.2 degrees, respectively. In summary, the peak pressure inside the pump is minimized when the valve pre-opening degree is around 0.8, while the pressure difference and flow velocity are relatively lower at a pre-opening degree of 0.6. It is recommended to start the pump with a valve pre-opening degree of around 0.6 to 0.8.

High-throughput generation of monodisperse double emulsions via controllable symmetric splitting in Y-shaped microchannels

To achieve high-throughput generation of monodisperse double emulsions via controllable symmetric splitting, the splitting dynamics of double emulsions in Y-shaped microchannels are systematically investigated by the combination of experimental study and numerical simulation. Four distinct breakup flow patterns of double emulsions splitting are initially identified, namely non-breakup, once uneven breakup, twice uneven breakup and twice even breakup, and the underlying hydrodynamic mechanisms of each flow pattern are further elucidated through the flow field structures and pressure distributions. The results show that the upstream pressure created by the flow obstruction of continuous phase governs the stable and symmetric splitting of double emulsions in Y-shaped microchannels. Effects of the flowrates of continuous phase, the outer and inner diameters of double emulsions, the physical properties of all the inner, middle and outer fluids as well as the angle of Y-shaped microchannel on the flow pattern transition laws are systematically clarified, and the corresponding universal flow pattern diagrams for predicting the critical boundary for the transition of flow patterns are established. Based on controllable symmetric splitting of double emulsions, three-level splitting microfluidic networks are rationally designed to achieve high-throughput generation of monodisperse double emulsions as well as monodisperse microcapsules via template synthesis. The results in this study not only advance the deep understanding of the breakup dynamics of double emulsions in Y-shaped microchannels, but also offer valuable guidance for the rational design of microfluidic devices for mass production of monodisperse double emulsions, thus providing a significant contribution to the fields of micro-chemical engineering and droplet microfluidics.

Performance analysis of a high-frequency two-stage proportional valve piloted by two high-speed on/off valve arrays

Two-stage proportional valves (TSPV) have been used extensively for electro-hydraulic control systems with large-flow applications. Due to the inherent characteristics of the pilot spool, such as hysteresis, motion quality, and dead zone, the dynamic performance of the traditional TSPV cannot be further improved. To solve this issue, this paper proposes a high-frequency two-stage proportional valve (HFTSPV) piloted by two high-speed on/off valve arrays, which integrates the advantages of dual nozzle flapper mechanism and parallel-connected valve technology. First, an entire mathematical model is established, in which some key parameters are estimated by experiments, such as the actual diameters and flow coefficients of orifices, and flow coefficient of pilot valve. Then, the influences of fixed orifices with different diameters on the dynamic characteristics of main spool are explored. Subsequently, the optimal diameter of fixed orifice is calculated theoretically by using the maximum pressure sensitivity and flow linearity, aiming to realize the high dynamic and small displacement fluctuation. Finally, step and sinusoidal tracking experiments show that the delay time of the HFTSPV is close to 3.3 ms, and the displacement fluctuation decreases with the increase of tracking frequency. Amplitude–frequency results indicate that −3 dB frequency of the HFTSPV reaches 16 Hz under ±50% full scale and 30 Hz under 0% –50% full scale.

Thermal transfer performance and flow instability analysis of direct steam generation for parabolic trough solar collectors

Parabolic trough solar direct-steam-generation (DSG) technology is the enabling technologies to achieve low carbon future. However, actual inlet boundary and flow boiling instabilities pose challenge to safe operation. In this paper, the coupled optical-thermal-flow pattern model for DSG loops is built utilizing conservation equations, separated flow model and Lagrangian method. The heat transfer performance, hydrodynamic characteristics and two-phase flow law of the loop are discussed under the coupled variation of direct radiation intensity (DNI), mass flow (m), inlet temperature (Tin) and inlet pressure (Pin). The correlation between multi-condition, thermodynamic characteristics and flow instability is analyzed. The results show that increasing Pin, Tin and DNI have almost no effect on the intermittent state. The percentage of annular flow only remained stable (about 84.8%) when the steam mass was 1. Increasing DNI and Tin did not effectively improve the flow heat transfer, while increasing Pin worsened the flow heat transfer and increased the probability that the annular flow would turn into stratified flow but could reduce the pressure drop and the fluid vapor-liquid density difference and stabilizes its hydrodynamic properties. The simultaneous increase in m not only weakens this effect and strengthens the heat transfer, but also permanently reduces the probability of stratified flow. The higher the Pin, Tin and DNI, the lower the flow instability of the DSG system. Manual operation is recommended to prevent the system having flow instability in the morning due to the lower solar radiation intensity and inlet temperature when the system is started in the morning.

Research on the impact of overflow well shut-in on wellbore integrity and safety

If an overflow occurs, the well must be closed immediately. To ensure the safety of the drilling wellbore in ultra-deep wells, it is critical to analyze the transient flow process and pressure fluctuations of the fluid in the annular space of the overflow well shut-in. This paper investigates the pressure fluctuation model of multi-phase fluid in the annular space after overflow occurs during gas well drilling, analyzes the influence factors of multi-phase fluid's pressure wave velocity, and simulates and analyses pressure fluctuation changes in the annular space in light of the impact of overflow well shut-in on wellbore safety. The model's correctness is verified by comparing it to experimental data published in the literature. The model is developed and examined using the example of a genuine gas well in western China. According to the study, as soon as the BOP closes, pressure rapidly increases to a high of 6.09 MPa at 5.89 s before falling to a valley of 4.68 MPa at 35.36 s. When the mild shut-in time lasts 20 s, the wellhead annular pressure reaches a maximum of 5.8 MPa. If the wellhead equipment can withstand the annular space's first pressure wave, a hard shut-in is recommended. To optimize the overflow well shut-in system and ensure wellbore safety, the change in pressure in the wellhead annular space as a result of varied shut-in timings and drilling fluid displacement is studied.

Flow Performance Analysis of Non-Return Multi-Door Reflux Valve: Experimental Case Study

Non-return multi-door reflux valves are essential in fluid control systems to prevent reverse flow and maintain system integrity. This study experimentally analyzes the flow performance of multi-door check valves under different operating conditions, focusing on pressure testing and evaluating their effectiveness in preventing backflow. A wide-ranging experimental setup was designed and implemented to simulate real-world scenarios, facilitating accurate measurement of flow rates, pressure differences, and valve response times. The collected experimental data were analyzed to evaluate the valve’s performance in terms of flow capacity, pressure drop, and hydraulic efficiency. Additionally, the effects of factors such as valve size, valve configuration, and fluid properties (water) on performance were considered. It was found that the non-return multi-door reflux valve has been proven effective and reliable in preserving system integrity and maintaining unidirectional flow at the same time during pressure testing. It exhibits no backflow, remains stable and constant across varied flow conditions, and demonstrates a low pressure drop and high flow capacity, making it suitable for critical pressure testing applications. The response curve revealed that valve opening takes longer to reach higher flow rates than closing, indicating pressure instability during transition periods. This non-linear relationship indicates possible irregularities in pressure drop response to flow rate changes, highlighting potential areas for further investigation.

Impacts of impeller blade number on centrifugal pump performance under critical cavitation conditions

The number of impeller blades is a significant geometric parameter that considerably impacts centrifugal pump performance. A transient numerical analysis of a centrifugal pump is conducted to examine the influence of the variable impeller blade number on pump performance under critical cavitation conditions. Six different impellers with 3, 5, 7, 8, 9, and 11 blades are examined numerically at a rotational speed of 2900 r/min when other impeller parameters remain unchanged. Fields of interior flow and properties of centrifugal pumps are studied concerning static pressure, velocity magnitude, and vapor volume fraction using ANSYS Fluent to perform the numerical simulation. The results show that numerical analysis can accurately predict centrifugal pump internal flow. The current results match experimental and numerical data for the NPSH, with a 4.65% discrepancy. Blade numbers affect the flow field and pressure amplitude, especially at the outlet region. As blade numbers increase, pressure increases, and the impeller with 11-blade has the maximum pressure amplitude. The impeller with a seven-blade achieved its highest efficiency level, exhibiting a 0.48% improvement under non-cavitation conditions and a 1.4% improvement under critical cavitation conditions compared to the original model. Furthermore, the cavity size on an individual blade of a model with three-blade is more extensive compared to other models. In addition, the impeller with a nine-blade exhibits the lowest value of the vapor volume percentage. This research analyses the influence of different blade numbers on the performance of centrifugal pumps while operating under critical cavitation conditions. It aims to provide novel insights into the flow characteristics associated with such circumstances.

The aqueous humour dynamics in primary angle closure disease: a computational study

PurposeTo create a computational fluid dynamics (CFD) model of ocular anterior segment for primary angle closure diseases (PACD) and assess the aqueous humour (AH) dynamics in different angle closure ranges...

Enhancement effect of semicoke waste heat on energy conservation and hydrogen production from biomass gasification

Key approaches to alleviating global warming and curbing fossil fuel depletion involve various industrial energy-conservation technologies and carbon dioxide (CO2) emission reduction methods. The production of hydrogen (H2)-rich gas from inexpensive and readily available biomass, as an alternative energy source, is becoming increasingly promising. However, this application faces challenges such as high energy consumption and low gas quality. In this study, the waste heat released by semicoke production from lignite gasification and CO2 from exhaust gas were utilized to gasify biomass. This approach aims to save energy in biomass gasification and use CO2 in exhaust gas to improve the H2 content in biogas. A simulation was conducted to recover semicoke waste heat by combining a suspension tube with CO2 flow to generate steam and high-temperature CO2, which were then simultaneously sent into a gasifier to produce H2 through biomass gasification. The results revealed that the rate of semicoke waste heat recovery exceeded 90 %. The yield of steam and the rate of waste heat recovery improved with increasing mass flow rate of semicoke and then slightly decreased with increasing steam pressure and CO2 mass flow rate. The yield of H2 increased with the semicoke mass flow rate and steam pressure. The rate of energy conservation ranged from 15 % to 239 %, peaking at a CO2 mass flow rate of 0.09 kg/s. Compared with the case without waste heat recovery, the economic benefits increased from 12 to 28 times.

A comparative study between EMG uroflowmetry with and without a catheter in children

ObjectivesTo evaluate the effect of urethral catheterization on the accuracy of EMG uroflowmetry in children with non-neurogenic voiding disorders during pressure-flow (PF) studies compared to the non-invasive EMG uroflowmetry test.MethodsA retrospective study of children undergoing a urodynamic evaluation at our institution between 8/2018 and 7/2022 was employed. Urination curves and pelvic floor muscle activity were compared between PF studies and non-invasive EMG uroflowmetry test. The non-invasive test was selected as the standard benchmark.Results104 children were tested, with 34 children (33%) being able to urinate only in a non-invasive EMG uroflowmetry. The percentage of boys unable to urinate with a catheter was significantly higher than girls (54% vs. 13%, p-value < 0.001). In 70 children, a normal bell-shaped urination curve was found in 13 compared to 33 children in the PF studies and non-invasive uroflowmetry, respectively. PF studies demonstrated a specificity of 39% (95% CI 23–57) and a positive predictive value (PPV) of 61% (95% CI 53–67) in finding non-bell-shaped curves. Relaxation of pelvic muscles was found in 21 (30%) as opposed to 39 (55%) of children in invasive and non-invasive EMG uroflowmetry, respectively (p-value = 0.5).ConclusionThe accuracy of PF studies in children, primarily in boys, compared to the non-invasive uroflowmetry, was poor. This may pose potential errors in diagnosis and subsequent treatment. We recommend completing a non-invasive EMG uroflowmetry in cases where the child refused to urinate, or pathology was found, requiring a modification in treatment.

Preparation irinotecan hydrochloride loaded PEGylated liposomes using novel method supercritical fluid and condition optimized by Box–Behnken design

A semi-synthetic camptothecin derivative known as irinotecan hydrochloride is frequently used to treat colorectal cancer, including colorectal adenocarcinoma and lung cancers involving small cells. Irinotecan has a very short half-life; therefore, continuous infusions are required to keep the drug’s blood levels at therapeutic levels, which could produce cumulative toxicities. Effective delivery techniques, including liposomes, have been developed to address these shortcomings. In this study, a continuous supercritical fluid approach dubbed Expansion Supercritical Fluid into an aqueous solution, in which the pressure decreases rapidly but remains over the critical pressure, is proposed to manufacture polyethylene glycolylated (PEGylated) liposomes carrying irinotecan hydrochloride. To accomplish this, PEGylated liposomes were created using a Box–Behnken design, and the operating parameters (flow rate, temperature, and pressure drop) were optimized. Encapsulation efficiency, mean size, and prepared liposome count were 94.6%, 55 nm, and 758 under ideal circumstances. Additionally, the stability of the PEGylated liposome was investigated during 8 weeks, and also PEGylated liposome-loaded irinotecan release profile was compared to conventional liposomes and free irinotecan, and a constant drug release was seen after the first burst release from liposomes.

Breakthrough curves of H2/CO2 adsorptions on CuBTC and MIL-125(Ti)_NH2 predicted by empirical correlations and deep neural networks

With the continuous emergence of new materials, efficiently screening suitable materials for hydrogen purification by pressure swing adsorption (PSA) technology has become a hot topic. Metal-organic frameworks (MOFs) hold significant promise in gas adsorption and separation due to their unique structure and versatility. Breakthrough curves depict the dynamic adsorption kinetics of multi-components in fixed-bed columns, offering a means to screen adsorbents. In this study, a deep neural network (DNN) model comprising 11 hidden layers is developed to predict the dynamic breakthrough behavior of MOF CuBTC and MIL-125(Ti)_NH2 adsorbents. The training data for the DNN were generated from a non-isothermal model established using Aspen Adsorption software. Results demonstrate that the DNN model effectively predicts the H2/CO2 breakthrough behavior on CuBTC and MIL-125(Ti)_NH2 adsorbents. Compared with empirical mathematical correlation models, the DNN can predict breakthrough profiles under varying operating conditions, exhibiting superior adaptability. Furthermore, parametric studies based on the DNN model reveal that initial temperature, adsorption pressure and feed flow rate play important roles in the dynamic adsorption process, significantly influencing the position and shape of the breakthrough curve. Decreasing the feed flow rate and initial temperature while increasing adsorption pressure can enhance breakthrough times and hydrogen purity. By comparing the breakthrough curves of the two adsorbents under different operating conditions for H2/CO2, the dimensionless breakthrough time of CO2 on the CuBTC adsorbent was longer. Additionally, simulation results of the PSA cycle suggest that CuBTC yields higher hydrogen purity than MIL-125(Ti)_NH2. Consequently, CuBTC is deemed more suitable for hydrogen purification of binary H2/CO2 mixtures than MIL-125(Ti)_NH2.