Liquid Particles Research Articles

Direct synthesis of fluoropolymer particles in ionic liquids via the photopolymerization of solid lubricants

A method for synthesizing fluorine-based polymer particles as additive agents in ionic liquid (ILs)-based lubricants for vacuum is proposed. This method can directly generate fluoropolymer nanoparticles inside an IL, while protecting the IL from light damage during polymerization. In this study, photocurable materials that are expected to be used as solid lubricants were selected, and the synthesis method, details of the polymer particles, and their effect on lubrication performance are described. This method reduced the friction coefficient, and traces of the polymer were observed on the surface of the test piece. The outgassed product from the lubricant did not differ from that from the pure IL under high vacuum.

Computational fluid dynamics-discrete element method simulation of stirred tank reactor for graphene production

Liquid phase exfoliation (LPE) process for graphene production is usually carried out in stirred tank reactor and the interactions between the solvent and the graphite particles are important as to improve the production efficiency. In this paper, these interactions were revealed by computational fluid dynamics–discrete element method (CFD-DEM) method. Based on simulation results, both liquid phase flow hydrodynamics and particle motion behavior have been analyzed, which gave the general information of the multiphase flow behavior inside the stirred tank reactor as to graphene production. By calculating the threshold at the beginning of graphite exfoliation process, the shear force from the slip velocity was determined as the active force. These results can support the optimization of the graphene production process.

Effects of process parameters on the spreading morphology of disc surface and aluminium powder produced by centrifugal atomisation

ABSTRACT An apparatus was developed to study the effects of operating parameters on liquid spreading and particle size in centrifugal atomisation. Different areas of aluminium spreading on the surface of the rotary disc were observed, in which the diameter of the ‘Plane area’ showed a linear relationship with the rotational speed. The microscopic morphology of the aluminium powder samples was analysed by scanning electron microscopy (SEM). The variation of particle size distribution curve with rotational speed was explored, and the shape of the curve was changed from ‘Single-peak’ to ‘Double-peak’ when the rotating speed increased to a certain value. The effect of the fragmentation mode on the particle size distribution and median diameter was analysed. The variation of the median diameter of the powder with the rotating speed was obtained. The effect of different disc configurations on the particle size was obtained.

A Tribological and Electrochemical Study of Protic Ionic Liquid and Bentonite Particles Used as Lubricating Additives in Water-Based Lubricants

A Tribological and Electrochemical Study of Protic Ionic Liquid and Bentonite Particles Used as Lubricating Additives in Water-Based Lubricants

Investigation of the Effect of Long-Term Exposure to Outdoor Air Pollution on Deaths in Konya with AirQ+ Software

Outdoor air pollution is one of the biggest environmental risks to public health and a problem that affects everyone in low-, middle- and high-income countries. Particulate matter (PM) is a common air pollutant consisting of a mixture of solid and liquid particles suspended in the air. PM2.5 and PM10 are the most common and are health related. The World Health Organization declared Particulate Matter (PM) as a carcinogen in 2013. The aim of this study was to calculate how much of the adult deaths aged 30 and over in Konya can be attributed to outdoor air pollution caused by PM2.5 pollutant. AirQ+ software was used to calculate the cases of deaths attributed to PM10 and PM2.5. The results show that 2163 premature deaths in 2017, 1582 in 2018 and 1278 in 2019 from long-term exposure to PM2.5 could be prevented if the PM2.5 concentration in the region does not exceed the recommended threshold of 10 µg/m3. Air pollution level is quite high in Konya. In the calculation made using AirQ+ software, the death rate attributable to air pollution in the population aged 30 and over was high, similar to previous studies in Turkey. The findings show that many premature deaths can be prevented by preventing air pollution.

Personal Protective Equipment (PPE) and Nurses’ Anxiety During the Covid-19 Pandemic

Anxiety felt by nurses is a vague fear accompanied by feelings of uncertainty, helplessness, isolation, and insecurity when performing nursing care during the Covid-19 pandemic. Nurses need personal protective equipment as a barrier against substance penetration, solid, liquid, or airborne particles to protect against injury or the spread of disease. The purpose of this study is to identify characteristics, length of work, PPE training, Psychologic services, PPE access, booster vaccination, standard PPE nurse anxiety and the correlation between PPE and anxiety on nurses in the COVID-19 room. This research is a quantitative study using a causal - comparative study design that is non-experimental (ex post facto). The sampling method used is purposive sampling technique approach with a sample of 90 respondents using data entry with demographic data sheet, PPE completeness checklist sheet to determine PPE completeness and to determine nursing anxiety using the Hamilton Anxiety Rating Scale questionnaire. Results showed the majority of nurses were middle-aged, woman, diploma, married, working more than 2 years, have participated in PPE training, not aware of access to psychological service, experienced easy accessibility of PPE, has not received a booster vaccine, using standardized PPE and experienced mild anxiety. This study shows that there is no significant difference in mean (p value> 0.05), which means that PPE training, psychological services, access to PPE, booster vaccinations, standardized PPE did not correlate to nurses’ anxiety. The government is expected to give intervention through policies to address nurses’ anxiety and factors related to this, such as providing effective counselling services.

Study on liquid dispersion characteristics in trickle bed reactor based on image processing

The liquid flow and distribution are key factors in determining the performance of a trickle bed reactor. It is highly challenging to examine the characteristics of liquid dispersion due to the complexity of the liquid flow mechanism in the trickle bed reactor. In this study, experimental research was performed to determine the impacts of gas/liquid velocity, particle packing method, and liquid properties on the characteristics of liquid dispersion in a pseudo-two-dimensional trickle bed reactor. A high-speed camera system was utilized to record the liquid flow and distribution in the reactor. An image processing method was proposed to obtain the particle surface wetting efficiency for quantifying the liquid distribution in the reactor. By combining liquid distribution images (qualitative information) and particle surface wetting efficiency (quantitative information) in the reactor under different conditions, it is feasible to evaluate the liquid dispersion in the trickle bed reactor in great detail.

An Axi-Symmetric Problem of Suspensions Filtering with the Formation of a Cake Layer

In this paper, we consider a vertically positioned cylindrical filtering element. Filtering occurs in the radial direction, therefore, the direction of the velocities of the liquid and suspended particles coincide with this radial direction. The flow can be considered to be one-dimensional and radially axisymmetric. To describe such a filtering process, the axisymmetric Stefan problem will be formulated. The radial mass balance formalism and Darcy’s law are utilized to obtain a basic equation for cake filtration. The boundary condition at the moving surface is derived and the cake filtration is formulated in a Stefan problem. Equations are derived that describe the dynamics of cake growth in the cake filtration, and they are numerically solved. The influence of different model parameters on the compression and fluid pressure across the cake and the growth of its thickness are studied.

Multimodal integrated flexible electronic skin for physiological perception and contactless kinematics pattern recognition

Multimodal integrated flexible electronic skin offers exceptional processing capability and versatility in various application scenarios. Researchers are devoting to developing nanomaterials or nano-devices with multidisciplinary functions. Herein, a trinary-mode integrated flexible electronic skin (E-Skin) was designed for physiological perception and contactless kinematics pattern recognition, which serves as real-time health monitor, electrode patch and contactless sensor. The composite film of liquid metal particles and thermoplastic polyurethane elastomers (LMPs@TPU) was prepared by a combination of electrostatic spinning, electrostatic spraying, and knife coating, which can be stretched up to 404.7 % at stress of 1Mpa. The film was endowed three functional modes through different forms of encapsulation, which allows for (1) detecting human arthrosis movements, muscle stretching, and inspiration, (2) achieving a real-time capture of Electrocardiogram (ECG) and surface electromyography (sEMG), and a Human-Machine Interaction (HMI) system for game control based on sEMG signals was also developed, (3) a contactless sensor combining with a machine learning model which realizes the recognition of human motion patterns with a receiver operating characteristic curve and area under curve score (ROC-AUC-score) of 0.99. The three models of this E-Skin highlight the significant potential for industrialization in various fields, such as HMI, physiological perception, virtual reality, and motion analysis.

Effects of the atomisation spray on heating transfer in evaporative condensers: A numerical study

Nowadays, due to the excellent performance of evaporative condenser, it has been widely applied in various industrial fields. Improving the heat transfer performance of evaporative condensers is of great importance to save water and energy. Spray features have a significant impact on the evaporative volume and efficiency of a heat-carrying agent (water) in an evaporative condenser, further dominating the condenser’s heat transfer performance. Therefore, it is important to improve the spray characteristics to enhance the heat transfer capacity of evaporative condensers. In this study, atomisation spray technology was introduced to an evaporative condensation system to optimise the spray process parameters. The objective is to elucidate the heat transfer capacity affected by the atomisation spray parameters, including spray density, spray distance, liquid particle size, air velocity, and air temperature. In addition, it is one of the aims of this paper to investigate the degree to which each parameter affects the heat transfer performance. This paper uses numerical simulations to investigate the relationship between the atomisation spray parameters and the heat transfer performance. A tube bundle model in an evaporative condenser was developed and Lagrangian method was used to treat the discrete phase. The results showed that a decrease in either liquid particle size or air temperature could improve the heat flux. In contrast, the heat flux exhibits a para-curve trend with an increase in any of the other three parameters. When other conditions are certain, the heat flux could reach up to 54.6 kW/m2 at an optimal atomisation spray density of 3.89 × 10−3 kg/(m·s). However, it could decrease by 53.23% with the increase in liquid particle size from 0.05 to 0.26 mm. What’s more, the atomisation spray density and liquid particle size are proven to be the two most critical factors; their grey relational coefficient exceeded 0.85. Moreover, the enhancements in the heat transfer capacity are found to be probably attributed to efficient liquid evaporation (removing substantial heat) and uniform liquid film distribution (avoiding dry zone and high thermal resistance). These findings can provide support information to enhance heat transfer via the atomisation spray technique for further research on evaporative condensers.

Research on Thermophoresis Deposition of Aerosol Particles

An aerosol is a system of liquid or solid particles in suspension in a gas, which includes both the particles and the suspended gas. The aim of this paper is to study the thermophoretic forces in aerosol systems. We introduce the concepts of particle size distribution, DLVO theory and multiphase flow models, followed by four case studies of thermophoretic deposition. This study has some limitations that need further investigation for a number of specific reasons. Firstly, the impact of thermophoresis is often overlooked in discussions about aerosols and their walls. Additionally, the focus has only been on solid walls, while the same problem applies to soft walls such as the human respiratory tract. The complexity of fluid models that involve multiple particles and forces also presents challenges. The task of examining the effects of temperature fields and temperature variations will be even more daunting. There is a pressing need for further research in this area.

Improving the separation efficiency of crude oil produced using an upgraded Gravity separator with Green Power generation

In this research paper, a new research path was opened with a new scientific view and a new philosophy for the goals of crude oil production through the development of important joints in the production process of crude oil where a horizontal three-phase separator was developed to produce green electrical energy without the need for combustion processes by creating a design for rotating parts capable of converting the momentum of the flow into electrical energy, the first part is the rotating diverter, which collides with the input mixture, which leads to a reduction in the momentum of the flow and an initial separation of gas from liquid, the collision results in the rotation of the wheel on which the concave bowls are installed, and thus generates electrical power by the dynamo connected to it. The second part of the separator that has been developed is to add a cone-shaped rotating external mist extractor with helical fin to perform two functions at the same time separating suspended liquid particles from the gas and generating clean electric power by the dynamo connected to it when it rotates under the influence of gas pressure. The efficiency of the developed separator parts was tested in performing their traditional function to separate the different phases and it was found that the developed separator is more efficient in addition to its ability to generate clean energy.

Acoustic detection potential of single particles in viscous liquids

Acoustic detection potential of single particles in viscous liquids

Surface Oxidation and Wetting Synergistic Effect of Liquid Metals.

Various functions of liquid metals are closely related to their surface performances, among which oxidation and wetting are the two most important surface processes. The two processes of liquid metals are inseparable in most practical applications; however, the coupling of oxidation and wetting of liquid metals has received little attention. Here, we demonstrate the synergistic effect of oxidation and wetting of liquid metals through establishing a liquid system containing the copper ion acid solution. By modulating the concentrations of copper ions and hydrogen ions, three different modes of the liquid metal surface are presented, where the oxidation process and the wetting process are in a competitive relationship. Whichever of the two processes is dominant can determine the stability of copper particles produced on the surface of liquid metals, that is, affect whether the "phagocytosis" process can occur. It is revealed that the magnitude of current density on the surface of liquid metals, caused by galvanic corrosion behavior between liquid metals and copper particles, is the key factor influencing the dominance of different surface processes of liquid metals. Utilizing the synergistic effect, we prepare a liquid metal film with adjustable reflectivity, in which surface states can be changed repeatedly between the bright state and the darken state by simple solution immersion. The liquid metal film with different surface states can show obvious difference in optical performance, which has application potential in color camouflage. Understanding the surface synergistic effect will facilitate further exploration of the abundant exotic liquid metal interface phenomena.

Fluidization of Swelling Particles at Elevated Temperatures

Semicrystalline polymer (e.g., polyethylene and polypropylene) particles may swell in solvent at elevated temperatures, inducing flow instability in operation, reactor blockage, and undesired product. Understanding the fluidization behavior of swelling particles at elevated temperatures is therefore of great significance. This work conducts an experimental study on the fluidization of polyethylene particles in an elevated-temperature liquid–solid fluidized bed. With the increase in temperature, particle swelling develops over two phases, i.e., non-cohesive swelling and cohesive swelling, which is different from the fluidization of cohesive particles in gas–solid systems. Four regimes can be identified through static bed height and pressure drop measurements, i.e., stable fluidization, noncohesive-swelling fluidization, cohesive-swelling fluidization, and full defluidization. A phase diagram was then obtained to demarcate these regimes. Furthermore, an energy balance model was proposed to predict the initial agglomerating temperature Tag of swelling particles for early warning of abnormal fluidization in practical operation.

Liquid Metal‐Enabled Microspheres with High Drug Loading and Multimodal Imaging for Artery Embolization (Adv. Funct. Mater. 18/2023)

Polymeric Binders In article number 2209413, Jing Liu, Linlin Fan, and co-workers demonstrate the liquid metal-enabled microspheres with diverse capabilities for artery embolization. By adsorbing silanized liquid metal particles on sulfonated agarose microspheres, high drug loading and multimodal imaging is displayed under computed tomography, magnetic resonance imaging and B-scan ultrasonography. Animal experiments show such microspheres' excellent biocompatibility and hemocompatibility to facilitate future clinical applications.

Divalent Ion Pillaring and Coating on Lithium Cobalt Oxide Cathode for Fast Intercalation of Li+ Ion with High Capacity

The development of high‐performance lithium‐ion batteries (LIBs) is essential for sustainable energy storage and utilization. Lithium cobalt oxide (LiCoO2, LCO) is widely used as a cathode material in LIBs due to its excellent electrochemical properties. However, its capacity is limited by structural changes and severe side reactions at high voltage and temperature. To overcome this issue, this study combines two strategies to enhance the intercalation kinetics of the LCO cathode. First, ionic pillars of various ions (e.g., Mg2+ and Ca2+) are doped to stabilize the structure at high voltage. Second, lithium‐ion conducting lithium phosphate (Li3PO4) is coated to prevent direct contact between the liquid electrolytes and LCO particles, minimizing the formation of resistive surface films. The combination of these strategies results in a synergetic effect that significantly improves the energy density, thermal stability, cycling stability, and rate capability of the cathode. A rate capability of 100 mAh g−1 at 10C is achieved, and a stable cycle performance with 98% capacity retention after 100 cycles at 0.5C is observed. Herein, the potential pathways of enhancing the energy density of current cathode materials through a synergistic combination of surface and structural engineering are highlighted.

Highly Stable Liquid Metal Conductors with Superior Electrical Stability and Tough Interface Bonding for Stretchable Electronics.

Ga-based liquid metal stretchable conductors have recently gained interest in flexible electronic devices such as electrodes, antennas, and sensors. It is essential to maintain electrical stability under strain or cyclic strain for reliable data acquisition and exhibit tough interfacial bonding between liquid metal and polymers to prevent performance loss and device failure. Herein, a highly stable conductor with superior electrical stability and tough interface bonding is introduced by casting curable polymers and a peeling-activated process from liquid metal particles. Based on the compensating effect of liquid metal, similar to the recharge relationship of water between rivers and lakes in nature, the conductor is not only strain-insensitive (ΔR/R0 < 10% for 100% strain) but also immune to cyclic deformation (ΔR/R0 < 7% with 5000 stretching cycles at 50% strain). Embedding liquid metal within the elastomer to create stretchable conductors effectively improves interfacial adhesion properties (the fluid-solid interfacial adhesion force increases from 0.48 to 0.62 mN/mm2). The constructed tough interface could even withstand sonication treatment. Finally, by combining strategies in material design and fabrication, an integrated array composed of vertical interconnect access and robust electrodes is fabricated, which simultaneously holds tough interfacial bonding with the upper and lower layers.

Comparative Studies about vaccine development for COVID-19

The human respiratory system can be infected with coronaviruses (CoVs), one of the families of viruses that can lead to symptoms ranging from mild to fatal. Seven genera of CVS have been identified as having human infection to date. The virus can spread as fine, liquid particles from the mouth or nose of an infected person when coughing, sneezing, speaking, or breathing. The diameter of droplet particles ranges from large to small. In this review, we summarize vaccine development for COVID-19. We anticipate this study will be a valuable resource for any researcher interested in creating a COVID-19 vaccine.

New Method for Measuring the Scattering Phase Function of Micron/Nano Particles

The scattering phase function is crucial to analyze the light transport in the micron/nano particle suspensions. A new method including a liquid–particle system and reference system is proposed to measure the scattering phase function of the liquid–particle suspensions. In this method, a reference system of a standard particle is used to obtain the correction factor to compensate for the influence of the cuvette. Experimental validation was conducted for monodisperse silicon dioxide microspheres and monodisperse polystyrene microspheres. By considering the influence of the cuvette, both theoretical and experimental analyses prove that the proposed method can achieve a good result in the measurement of the scattering phase function of liquid–particle suspensions for particles with unknown size parameters and optical constants, especially when the size parameter of the particle is larger than 10. The correction factors of scattering light distribution of silicon dioxide microsphere suspensions with various mean particle sizes were obtained and analyzed. This method provides an alternative and simple way of measuring the scattering phase function of micron/nano particle suspensions.