Trapped Air Bubbles Research Articles

Polydimethylsiloxane Surface Modification of Microfluidic Devices for Blood Plasma Separation.

Over the last decade, researchers have developed a variety of new analytical and clinical diagnostic devices. These devices are predominantly based on microfluidic technologies, where biological samples can be processed and manipulated for the collection and detection of important biomolecules. Polydimethylsiloxane (PDMS) is the most commonly used material in the fabrication of these microfluidic devices. However, it has a hydrophobic nature (contact angle with water of 110°), leading to poor wetting behavior and issues related to the mixing of fluids, difficulties in obtaining uniform coatings, and reduced efficiency in processes such as plasma separation and molecule detection (protein adsorption). This work aimed to consider the fabrication aspects of PDMS microfluidic devices for biological applications, such as surface modification methods. Therefore, we studied and characterized two methods for obtaining hydrophilic PDMS surfaces: surface modification by bulk mixture and the surface immersion method. To modify the PDMS surface properties, three different surfactants were used in both methods (Pluronic® F127, polyethylene glycol (PEG), and polyethylene oxide (PEO)) at different percentages. Water contact angle (WCA) measurements were performed to evaluate the surface wettability. Additionally, capillary flow studies were performed with microchannel molds, which were produced using stereolithography combined with PDMS double casting and replica molding procedures. A PDMS microfluidic device for blood plasma separation was also fabricated by soft lithography with PDMS modified by PEO surfactant at 2.5% (v/v), which proved to be the best method for making the PDMS hydrophilic, as the WCA was lower than 50° for several days without compromising the PDMS's optical properties. Thus, this study indicates that PDMS surface modification shows great potential for enhancing blood plasma separation efficiency in microfluidic devices, as it facilitates fluid flow, reduces cell aggregations and the trapping of air bubbles, and achieves higher levels of sample purity.

Experimental study on the distribution and growth characteristics of trapped air bubbles in ice slices at different freezing temperatures

Icing is a phenomenon that exists widely in daily life and industry, and always brings some disadvantages. The dissolved air tends to become micro bubbles and trapped in ice, which have an effect on the physical properties of the ice. To explore the distribution and growth characteristics of trapped air bubbles in ice, experiments are carried out in a horizontal Hele-Shaw cell at different freezing temperatures. Results show that the trapped air bubbles in ice are classified into egg-shaped bubbles and needle-shaped bubbles according to an aspect ratio of bubble length to width larger and smaller than five. All the widths, lengths, and volumes of egg-shaped and needle-shaped bubbles increase with the distance from the cooler increasing and the freezing temperature decreasing. The length and volume of needle-shaped bubbles are larger than those of egg-shaped ones. The behaviors of trapped air bubbles are mainly affected by the freezing rate. When the bubble growth rate is greater than 20 μm/s, there are only egg-shaped bubbles in the ice, and when the bubble growth rate is less than 10 μm/s, there are only needle-shaped bubbles in the ice. The volumes of ESBs and NSBs both increase linearly with the bubble growth time at all freezing temperatures. These findings help deepen the understanding of trapped air bubbles in ice and provide guidance for improving icing and optimizing deicing strategies.

Growth and distribution characteristics of trapped air bubbles in ice slices

Icing is a complex phase change process that is widespread in nature and industry and may have a number of negative effects. During the freezing of water into ice, air bubbles are often trapped in ice and affect the physical properties of the ice. To control the icing process, it is necessary to study these air bubbles in ice. Here, an experimental setup is built to study the growth and distribution characteristics of trapped air bubbles. The results show that the critical freezing rates for the transitions from the egg-shaped bubble region to the egg-/needle-shaped bubble region and from the egg-/needle-shaped bubble region to needle-shaped region are 22.45 ± 3.24 and 12.64 ± 1.65 μm/s, respectively. A mathematical model that can predict bubble growth is obtained by coupling the gas diffusion equation, Henry's law, and the Young–Laplace equation. The model shows that both the maximum width of the bubble and the distance between adjacent bubbles mainly depend on the freezing rate and are proportional to the inverse of the second power of the freezing rate, meaning that the maximum width and the distance gradually increase as the freezing rate decreases. These results contribute to a better understanding of icing mechanisms and inform the optimization of anti-icing and deicing methods.

Ink Fluidic Behaviors during R2R Slot Die Coating on Quality Thin Film Formation

High throughput slot die coating is a desired fabrication method for flexible display, solar cell, Li-ion battery pack, intelligent package and wearable electronics. In this study, the stability of the thin film formation by slot die coating is investigated through theoretical, experimental and numerical studies with the combined effects of the fluid and substrate surface characteristics. The theoretical model based on the viscous capillary theory reveals fluid upstream and downstream distribution patterns and associated parameters that descript the coating layer stability. A 3D model based on the volume of fluid method (VOF) is developed to illustrate the coating process affecting the coating quality by the substrate velocity and flow rate. The numerical and experimental results agree that higher viscosity fluid is more prone to trap air bubbles and/or to create de-wetting areas while as the lower viscosity fluid were responsible for upstream liquid dripping. Boundary by the fluid, substrate, and operating parameters, our numerical study has developed the coating operation window to minimize or eliminate coating defects which has been confirmed by the experiments. These study results could lead high yield coating processes and efficiency in large area functional coating production.

An experimental study on the effect of CO2 laser powers on melting characteristics of ice with trapped air bubbles under vertical irradiation

Icing occurs frequently and plays negative effects in natural and industrial fields. Air bubbles are always trapped in the ice during freezing, and then affect the thermal and mechanical properties of ice. As a typical non-contact and high-efficiency deicing method, laser deicing technology is tested on melting ice with trapped air bubbles, under vertical CO2 laser irradiation and natural convection, with the laser power varied at a range of 20 ∼ 60 W. As resulted, the axial melting rate tends to increase and then decrease with increasing laser power. The maximum values of average and instantaneous axial melting rate at 40 W are 5.46 mm/s and 12.32 mm/s, respectively. At 40 ∼ 60 W, the higher the laser power, the larger the average melting length after stabilization. At 40 W and 60 W, the average melting length are 3.60 mm and 5.59 mm, respectively. It is found little correlation between the melting angle and laser power. At 30 W and 50 W, the maximum melting angles in the front view are 2.49° and 1.15°, respectively. During the whole melting process, the highest energy efficiency is maintained at 20 W, and the maximum energy efficiency is 69.1%. Results of this study could provide a reference for the application of laser deicing technology.

Transcranial focused ultrasound-induced blood‒brain barrier opening in mice without shaving hairs

Acoustic coupling through hairs remains a challenge to performing transcranial-focused ultrasound procedures. Here, we demonstrated that this challenge could be addressed by using oil as the coupling medium, leveraging oil's high affinity to hairs due to their inherent hydrophobicity. We compared focused ultrasound-induced blood–brain barrier opening (FUS-BBBO) outcomes in mice under three coupling conditions: oil with hairs (“oil + hairs”), ultrasound gel with hair shaving (“ultrasound gel + no hair”), and ultrasound gel with hairs (“ultrasound gel + hairs”). The quality of the coupling was evaluated by {mathrm{T}}_{2}-weighted magnetic resonance imaging (MRI) and passive cavitation detection (PCD). The outcome of FUS-BBBO was assessed by MRI contrast agent extravasation using in vivo {mathrm{T}}_{1}-weighted contrast-enhanced MRI. It was also evaluated by ex vivo fluorescence imaging of the mouse brain after intravenous injection of a model drug, Evans blue. The results showed that “oil + hairs” consistently achieved high-quality acoustic coupling without trapping air bubbles. The FUS-BBBO outcome was not significantly different between the “oil + hairs” and the “ultrasound gel + no hair” groups. These two groups had significantly higher levels of BBB opening than the “ultrasound gel + hairs” group. This study demonstrated that oil could be a coupling medium for transcranial FUS procedures without shaving hairs.

Bubble-free diatoms polymerase chain reaction

Polymerase chain reaction (PCR) in small fluidic systems not only improves speed and sensitivity of deoxyribonucleic acid (DNA) amplification but also achieves high-throughput quantitative analyses. However, air bubble trapping and growth during PCR has been considered as a critical problem since it causes the failure of DNA amplification. Here we report bubble-free diatom PCR by exploiting a hierarchically porous silica structure of single-celled algae. We show that femtoliters of PCR solution can be spontaneously loaded into the diatom interior without air bubble trapping due to the surface hydrophilicity and pore structure of the diatom. We discover that a large pressure gradient between air bubbles and nanopores rapidly removes residual air bubbles through the periodically arrayed nanopores during thermal cycling. We demonstrate the DNA amplification by diatom PCR without air bubble trapping and growth. Finally, we successfully detect DNA fragments of SARS-CoV-2 with as low as 10 copies/μl by devising a microfluidic device integrated with diatoms assembly. We believe that our work can be applied to many PCR applications for innovative molecular diagnostics and provides new opportunities for naturally abundant diatoms to create innovative biomaterials in real-world applications.

Prevalence of Trichomonas vaginalis Infection among Women of Reproductive Age in Anambra State, South Eastern, Nigeria

Aim: This study was undertaken to determine the prevalence of Trichomonas vaginalis infection among women of reproductive age in some selected hospitals in Awka, Anambra State, Nigeria.
 Methods: This study, conducted from October to December 2021, involved 200 women aged 20 years and above as participants. Prior to specimen collection, informed consent was obtained from each woman by qualified medical personnel. High vaginal swab sticks, labeled and sterile, were used to meticulously and aseptically collect specimens from the high vaginal area. A few drops of normal saline were added to each swab stick, and within 30 minutes of collection, a wet mount examination was performed to ensure optimal results. For the wet preparation of vaginal discharge, a drop from the sample was applied to a clean glass slide with a cover slip, avoiding the trapping of air bubbles. The wet smear was then examined under a microscope using a low-power objective (x10) followed by a high-power objective (x40) to detect motile T. vaginalis. The vaginal secretion was characterized by the presence of epithelial cells, white blood cells, and red blood cells. The T. vaginalis trophozoite was identified based on its oval shape, flagellation, and distinct jerky movement.
 Results: The study area had an overall prevalence rate of 11.0% for T. vaginalis infection. Among the selected hospitals, COOUTH had the highest prevalence at 13.24%, while Rock Foundation Hospital had the lowest at 6.67%. Prevalence varied across age groups, with the highest rate of 16.42% found in the 30-39 years age group, and the lowest rate of 5.0% in the 20-29 years age group. Divorced women had the highest prevalence at 60.0%, while singles had the lowest at 4.7% among the marital groups. Among different occupations, traders had the highest prevalence at 12.24%, whereas students and civil servants had the lowest rates at 4.0% and 7.72%, respectively. T. vaginalis infection was only observed in non-pregnant women, with a prevalence rate of 13.3%.
 Conclusion: T. vaginalis infection is prevalent among sexually active women of reproductive age in the study area. The findings highlight the importance of practicing good personal hygiene and being faithful to a single sexual partner. It is recommended to raise public awareness regarding the prevention and control of T. vaginalis in order to reduce its prevalence among women in the study area.

Effect of bubble volume on the sweeping velocity of air bubbles in horizontal pipelines in water supply system

Trapped air bubbles in pipelines significantly affect the safety and efficiency of water supply systems, potentially inducing water hammer and leading to pipeline explosions and interruptions. This study investigates the sweeping velocity of air bubbles in horizontal pipelines by analyzing the forces acting on a single air bubble and deriving a theoretical expression for calculating the sweeping velocity. Physical model experiments and numerical simulations are conducted to examine the variations in sweeping velocity with respect to bubble volume and dimensionless bubble volume. Results indicate that the sweeping velocity increases with bubble volume, and the diameter of the pipeline significantly affects the movement of air bubbles. These findings contribute to a better understanding of air bubble behavior in horizontal pipelines and can inform strategies for mitigating risks associated with trapped air bubbles, ultimately improving the safety and reliability of water supply systems.

Air-Bubble-Insensitive Microfluidic Lactate Biosensor for Continuous Monitoring of Lactate in Sweat.

This study aimed to develop a lactate sensor with a microchannel that overcomes the issue of air bubbles interfering with the measurement of lactate levels in sweat and to evaluate its potential for continuous monitoring of lactate in sweat. To achieve continuous monitoring of lactate, a microchannel was used to supply and drain sweat from the electrodes of the lactate sensor. A lactate sensor was then developed with a microchannel that has an area specifically designed to trap air bubbles and prevent them from contacting the electrode. The sensor was evaluated by a person while exercising to test its effectiveness in monitoring lactate in sweat and its correlation with blood lactate levels. Furthermore, the lactate sensor with a microchannel in this study can be worn on the body for a long time and is expected to be used for the continuous monitoring of lactate in sweat. The developed lactate sensor with a microchannel effectively prevented air bubbles from interfering with the measurement of lactate levels in sweat. The sensor showed a concentration correlation ranging from 1 to 50 mM and demonstrated a correlation between lactate in sweat and blood. Additionally, the lactate sensor with a microchannel in this study can be worn on the body for an extended period and is expected to be useful for the continuous monitoring of lactate in sweat, particularly in the fields of medicine and sports.

Pore doublet micromodel experiments of evaporation influence on pre-event water entrapment and pre-event and event water interaction

The stable isotopic signature of xylem water differs from those of rainfall and river water. Without considering the water exchange through the vapor phase, this phenomenon implies that when the event water (new water) infiltrates the soil, a part of the pre-event water (old water) is isolated. The isolation and immobilization of old water are suspected because of the low matrix potential. Because evaporation is the main process that can reduce the matrix potential after quick gravitational drainage, we conjectured that after evaporation, the old water hides in small pores and increases the likelihood of air entrapment, which separates the new and old water. To examine and visualize the potential effect of evaporation on the interactions between old and new water, we performed a series of wetting–drainage–evaporation–wetting experiments within pore doublet micromodels (PDMs). The experimental results showed that air bubbles are trapped when the menisci of the residual liquid are sufficiently far from the inlet and outlet of the PDM. Evaporation can increase these distances, resulting in the formation of larger air bubbles. The air bubble trapped upstream prevents the invading liquid from quickly flushing the original residual liquid out of the PDM. Nevertheless, the invading wetting liquid is still able to bypass the trapped air bubbles and mix with the residual wetting phase via corner flow. In addition, the remobilization of the upstream bubble enhances the process of removing the old trapped liquid.

SonoRotor: An Acoustic Rotational Robotic Platform for Zebrafish Embryos and Larvae

Rotation manipulation is an essential component of biological microscopy and can become integral to multidisciplinary research and applications. On-chip rotation of microobjects with spherical shapes like biological cells and model organisms has been demonstrated based on advanced microfluidic techniques. To date, however, biocompatible, easy-to-fabricate, easy-to-operate, and controlled rotation of small animal models with slender bodies remains a challenge. Here, we present SonoRotor, a miniaturized acoustic rotation platform for animal models using a single elongated acoustically activated air bubble. In the presence of an acoustic field, the trapped elongated air bubble oscillates and induces a polarized vortex in the surrounding liquid. Zebrafish embryos (spherical) and larvae (slender), typically larger than hundreds of micrometers, become trapped near the oscillating bubble and undergo a controllable, high-speed, and stable out-of-plane rotation. By controlling the voltage applied to our device, we can adjust the rotation speed of the zebrafish. The developed acoustic rotation manipulation platform is simple, cost-effective, allows multiview imaging, high-throughput operation, and can be combined with downstream analytical techniques to perform a variety of biological micromanipulation on small animal models.

Interface Wetting Driven by Laplace Pressure on Multiscale Topographies and Its Application to Performance Enhancement of Metal-Composite Hybrid Structure

Surface topography reconstruction is extensively used to address the issue of weak bonding at the polymer-metal interface of metal-composite hybrid structure, while enhancement from this approach is seriously impaired by insufficient interface wetting. In this study, the wetting behavior of polymer on aluminum surfaces with multiscale topographies was theoretically and experimentally investigated to realize stable and complete wetting. Geometric dimensions of multiscale surface topographies have a notable impact on interfacial forces at the three-phase contact line of polymer/air/aluminum, and a competition exists between Laplace pressure and bubble pressure in dominating the wetting behavior. Laplace pressure facilitates the degassing of trapped air bubbles in grooves, bringing more robust interfacial wettability to grooves than dimples and grids. Conversely, dimples with excessive dimensions generate interfacial pores, and this intrinsic mechanism is theoretically unraveled. Moreover, different degrees of interface wetting cause variations in bonding strength of polymer-aluminum interface, which changes from ∼18% improvement to ∼17% reduction compared to original strength. Finally, groove topography perfectly achieved complete wetting between polymer and aluminum and consequently improved flexure performance by over 11% for the aluminum-carbon fiber hybrid side impact bar, which verifies the importance of complete wetting at a part scale. This study deepens the understanding of wetting behavior and clarifies the intrinsic correlation between interfacial bonding performance and surface topography.

Shaveless focused-ultrasound-induced blood-brain barrier opening in mice

To demonstrate that focused ultrasound-induced blood-brain barrier opening (FUS-BBBO) in mice can be achieved without shaving hairs. We performed FUS-BBBO in mice by using oil as the coupling medium without shaving hairs. The hydrophobic nature of oil leads to a higher affinity to hair than water-based ultrasound gel. FUS-BBBO outcome was compared under three conditions: “oil + hairs,” “gel + hairs,” and “gel + no hairs.” T2-weighted, T1-weighted MRI, and fluorescence imaging of the ex vivo brain slices were performed to measure the quality of coupling and outcome of FUS-BBBO. Results showed that “oil + hairs” consistently achieved high-quality acoustic coupling without trapping air bubbles (Figures A & B). FUS-BBBO outcome was not significantly different between the “oil + hairs” group and the “gel + no hairs” group based on T1-weighted MRI (Figures C & D) and ex vivo fluorescence imaging (Figure E). The FUS-BBBO efficiencies for both the “oil + hairs” and “gel + no hairs” groups were significantly higher than the “gel + hairs” group. This study demonstrated that FUS-BBBO in mice could be achieved without shaving hairs. Oil provides a simple solution for achieving effective acoustic coupling for transcranial FUS procedures.

A versatile approach to numerically investigate the trapped air bubble in piezoelectric inkjet printing process

A versatile approach to numerically investigate the trapped air bubble in piezoelectric inkjet printing process

Prevalenţa infecţiei cu Trichomonas vaginalis la femeile de vârstă reproductivă din Kosovo

Aim. This study was undertaken to determine the prevalence of Trichomonas vaginalis infection in women of reproductive age from Kosovo. Methodology. The study was carried out in the Obstetrics and Gynecology Clinic of the Faculty of Medicine, University of Pristine, Kosovo, between April and July 2022. The study population consisted of a total of 207 women. Sexually active women aged at least 20 years old were included in the study. A semi-structured questionnaire was distributed to the participants to seek for information such as age, marital status, occupation and pregnancy status. Every woman’s informed consent was sought before the collection of specimens by qualified medical personnel. The specimens were carefully and aseptically collected from the high vaginal area using well-labeled, sterile, non-abrasive high vaginal swab sticks. A few drops of normal saline were added to each swab stick, and a wet mount examination was performed within less than half an hour of collection in order to get optimal results. The wet preparation of the vaginal discharge was made by applying a drop from the sample to a small area of a clean glass slide with a cover slip in order not to trap air bubbles. The wet smear was examined microscopically for motile T. vaginalis with a low-power objective (x10) and then with a high-power objective (x40). The vaginal secretion was characterized by the presence of epithelial cells, white blood cells and red blood cells. The T. vaginalis trophozoite was identified by its oval, flagellated and distinctive motility (jerky movement). Results. An overall prevalence rate of 12.56% was found in Kosovo. The prevalence of T. vaginalis infection differed from place to place. It varied as well among age groups, showing the highest prevalence in the age group of 30-39 years old (13.63%), and the lowest in the age group of 20-29 years old (5.70%). The prevalence varied with marital groups, being the highest in divorced women (30.76%) and the lowest among singles (6.74%). The prevalence rate was also observed to be highest among the employed (19.71%) and lowest among students (14.81%) and unemployed (7.33%). T. vaginalis infection was observed in non-pregnant women in a prevalence rate of 15.20%. Conclusions. T. vaginalis infection is prevalent in women of reproductive age, as evident in our country. The infection is common in sexually active female participants, especially in those with multiple sex partners. Proper personal hygiene, faithfulness to one sexual partner, and massive public awareness on the prevention and control of T. vaginalis are advised to reduce its prevalence among women of reproductive age in our country.

Phase Field Modeling of Air Entrapment in Binary Droplet Impact with Solidification Microstructure Formation

A novel numerical model was developed to investigate air entrapment in binary droplet impact with solidification microstructure formation under practical plasma spraying conditions. The evolving liquid–gas interface was tracked by the explicit finite difference solution to the Cahn–Hilliard equation, coupled with the Navier–Stokes equations. Another diffuse interface model was invoked to trace solid–liquid and grain–grain boundaries. The model was discretized using an explicit finite difference method on a half-staggered grid. The velocity pressure coupling was decoupled with the projection method. The in-house code was written in Fortran and was run with the aid of the shared memory parallelism, OpenMP. The time duration over which gas compressibility matters was estimated. Typical cases with air entrapment were studied with the model. The effect of droplet porosity on air entrapment was probed into as well: the larger the porosity of a droplet, the bigger the trapped air bubble. The grain growth near the air bubble is skewed. Moreover, a case without air entrapment was also shown herein to stress that air bubbles could be suppressed or even eliminated in plasma spraying by adjusting the landing positions of successive droplets.

Microcapillary cell extrusion deposition with picolitre dispensing resolution

Extrusion-based cell deposition has become a prominent technique for expanding bioprinting applications. However, the associated print resolution in the order of nanolitre or above has been a limiting factor. The demand for improving print resolution towards the scale of a single cell has driven the development of precision nozzle extrusion, although the benefits gained remain ambiguous. Here, aided by in situ imaging, we investigated the dynamics of cell organisation through an extrusion-based microcapillary tip with picolitre precision through in-air or immersion deposition. The microcapillary extrusion setup, termed ‘Picodis’, was demonstrated by generating droplets of colouring inks immersed in an immiscible medium. Next, using 3T3 fibroblast cells as an experimental model, we demonstrated the deposition of cell suspension, and pre-aggregated cell pellets. Then, the dynamic organisation of cells within the microcapillary tip was described, along with cell ejection and deposition upon exiting the tip opening. The vision-assisted approach revealed that when dispersed in a culture medium, the movements of cells were distinctive based on the flow profiles and were purely driven by laminar fluid flow within a narrow tip. The primary process limitations were cell sedimentation, aggregation and compaction, along with trapped air bubbles. The use of picolitre-level resolution microcapillary extrusion, although it provides some level of control for a small number of cells, does not necessarily offer a reliable method when a specified number of cells are required. Our study provides insights into the process limitations of high-resolution cell ink extrusion, which may be useful for optimising biofabrication processes of cell-laden constructs for biomedical research.

Tissue Barrier-on-Chip: A Technology for Reproducible Practice in Drug Testing.

One key application of organ-on-chip systems is the examination of drug transport and absorption through native cell barriers such the blood–brain barrier. To overcome previous hurdles related to the transferability of existing static cell cultivation protocols and polydimethylsiloxane (PDMS) as the construction material, a chip platform with key innovations for practical use in drug-permeation testing is presented. First, the design allows for the transfer of barrier-forming tissue into the microfluidic system after cells have been seeded on porous polymer or Si3N4 membranes. From this, we can follow highly reproducible models and cultivation protocols established for static drug testing, from coating the membrane to seeding the cells and cell analysis. Second, the perfusion system is a microscopable glass chip with two fluid compartments with transparent embedded electrodes separated by the membrane. The reversible closure in a clamping adapter requires only a very thin PDMS sealing with negligible liquid contact, thereby eliminating well-known disadvantages of PDMS, such as its limited usability in the quantitative measurements of hydrophobic drug molecule concentrations. Equipped with tissue transfer capabilities, perfusion chamber inertness and air bubble trapping, and supplemented with automated fluid control, the presented system is a promising platform for studying established in vitro models of tissue barriers under reproducible microfluidic perfusion conditions.

Numerical Modelling of Coolant Filling and De-aeration in a Battery Electric Vehicle Cooling System

<div class="section abstract"><div class="htmlview paragraph">Trapped air bubbles inside coolant systems have adverse effect on the cooling performance. Hence, it is imperative to ensure an effective filling and de-aeration of the coolant system in order to have less air left before the operation of the coolant system. In the present work, a coolant/air multiphase VOF method was utilized using the commercial CFD software SimericsMP+® to study the coolant filling and subsequent de-aeration process in a Battery Electric Vehicle (BEV) cooling system. First, validations of the numerical simulations against experiments were performed for a simplified coolant recirculation system. This system uses a tequila bottle for de-aeration and the validations were performed for different coolant flow rates to examine the de-aeration efficiency. A similar trend of de-aeration was captured between simulation and experimental measurement. Next, the same numerical techniques were further applied to a BEV cooling system to evaluate the efficiency of de-aeration processes. The first step of the process involved a vacuum filling simulation. After the filling process, the air remained in the system is about 10% of total system volume. Different combinations of a multi-position valve and pump on/off cycles strategies were explored to decrease trapped air in the system. It is found that the opening/closing strategy of the multi-position valve plays a crucial role for an effective de-aeration. The devised methodology is observed to be numerically robust and accurate, while having good computational efficiency for modelling the coolant filling and de-aeration process that takes large physical time.</div></div>