Liquid Deposition Research Articles

Standard Methods for Evaluating Electrostatic Spray Charge and Deposition of Conductive Liquids Used for Surface Disinfection

Standard Methods for Evaluating Electrostatic Spray Charge and Deposition of Conductive Liquids Used for Surface Disinfection

Optimal liquid sulfur deposition dynamics for fast-charging Li-S batteries

Optimal liquid sulfur deposition dynamics for fast-charging Li-S batteries

TiO2-hBN nanocomposite coating with excellent wear and corrosion resistance on Ti6Al4V alloy prepared by plasma electrolytic oxidation

Hexagonal boron nitride (hBN) is recognized for its promising application prospects in anti-friction and corrosion resistance due to its self-lubrication and excellent impermeability to gases and liquids. In this study, the TiO2-hBN nanocomposite coatings are prepared via the liquid plasma-assisted particle deposition sintering (LPDS) technology, enabling compact and uniform growth of hBN on the Ti6Al4V surface. Results indicate that the dense and stable plasma at the coating/electrolyte interface facilitates the deposition and sintering of hBN particles, effectively filling surface defects and achieving a coating density of 86.7 %. The friction coefficient of the TiO2-hBN nanocomposite coating significantly decreases from 0.54 (titanium alloy) to 0.28, remaining stable even after 2000 sliding cycles. Compared to the substrate, the wear rate (4.3 × 10−4 mm3N−1 m−1) of nanocomposite coating drops by 70.8 %, which is primarily attributed to the self-lubricating property of hBN, reducing the frictional shear stress. Moreover, the TiO2-hBN nanocomposite coating also has excellent corrosion resistance due to the hBN sheet filling internal defects and inhibiting the corrosion reaction. All these merits render the LPDS technology competitive in expanding the severe service conditions of titanium alloys in aerospace and marine engineering equipment.

Highly para-selective alkylation of toluene by methyl mercaptan over silylated ZSM-5 zeolite

Friedel-Crafts alkylation of toluene with methyl mercaptan has been investigated in the presence of H-ZSM-5 and SiO2/H-ZSM-5 catalysts. The silica layers have been built on H-ZSM-5 zeolite by chemical liquid deposition of tetraethyl orthosilicate. The passivation with silica of the external surface of H-ZSM-5 zeolite has been confirmed by FT-IR spectroscopy and mesitylene isomerization, used as a model reaction. All catalysts exhibited notable behavior in the alkylation of toluene to xylenes. Efficiencies higher than 98 % in alkylation for both toluene and methyl mercaptan were obtained at 375 °C. In terms of para-selectivity, outstanding performance was revealed by the silylated zeolites. Thus, over 12 % SiO2/H-ZSM-5, at 375 °C and WHSV = 9.4 gtoluene+CH3SH gcat-1h−1, the para-xylene selectivity was close to 100 %. The experimental apparent activation energy for the toluene alkylation with methyl mercaptan catalyzed by H-ZSM-5 was 80 kJ/mol.

Effect of external surface barriers over hierarchical ZSM-5 zeolite on n-heptane catalytic cracking

To better understand external surface barriers on hierarchical ZSM-5 zeolite, SiO2 layers were constructed over zeolite nanocrystal by using chemical liquid depositions (CLD). Diffusion measurement showed that the apparent diffusion rate over the zeolite was increased by up to 142 % after SiO2 deposition, indicating that the external surface barriers had been significantly reduced. The performance of hierarchical ZSM-5 zeolite for n-heptane catalytic cracking indicated that the catalytic activity (TOF) was increased from 0.55 to 0.91 s−1 after 3 nm layer of SiO2 deposition, leading to a total yield increase of ethylene and propylene by up to 23 %. The strong positive correlation of catalytic activity with apparent diffusion rate suggests that reducing external surface barriers can improve the utilization efficiency of active sites in micropores and enhance the catalytic activity of the zeolite. These results demonstrate that CLD of SiO2 can reduce external surface barriers on hierarchical zeolite, thereby improving its cracking performance.

Evaluation of droplet deposition parameters based on the Genetic-Otsu algorithm.

Pesticide spraying is a cost-effective way to control crop pests and diseases. The effectiveness of this method relies on the deposition and distribution of the spray droplets within the targeted application area. There is a critical need for an accurate and stable detection algorithm to evaluate the liquid droplet deposition parameters on the water-sensitive paper (WSP) and reduce the impact of image noise. This study acquired 90 WSP samples with diverse coverage through field spraying experiments. The droplets on the WSP were subsequently isolated, and the coverage and density were computed, employing the fixed threshold method, the Otsu threshold method, and our Genetic-Otsu threshold method. Based on the benchmark of manually measured data, an error analysis was conducted on the accuracy of three methods, and a comprehensive evaluation was carried out. The relative error results indicate that the Genetic-Otsu method proposed in this research demonstrates superior performance in detecting droplet coverage and density. The relative errors of droplet density in the sparse, medium, and dense droplet groups are 2.7%, 1.5%, and 2.0%, respectively. The relative errors of droplet coverage are 1.5%, 0.88%, and 1.2%, respectively. These results demonstrate that the Genetic-Otsu algorithm outperforms the other two algorithms. The proposed algorithm effectively identifies small-sized droplets and accurately distinguishes the multiple independent contours of adjacent droplets even in dense droplet groups, demonstrating excellent performance. Overall, the Genetic-Otsu algorithm offered a reliable solution for detecting droplet deposition parameters on WSP, providing an efficient tool for evaluating droplet deposition parameters in UAV pesticide spraying applications.

Fabrication of functional surfaces using layer height method in material extrusion type 3D printing

Various layer stacking methods have been employed in material extrusion type three-dimensional (3D) printing to utilize their potential for addressing the inherent technological limitation of reduced surface quality due to layer stacking. The process involved fabricating a material extrusion type 3D printed mold using diverse layer height-changing methods and subsequently replicating the surface pattern with the polymer. This approach is called the layer height method (LHM) and comprises three distinct variations. The first method involves altering the height of the individual layers to generate diverse surface morphologies and, consequently, varying the range of water contact angles. The second method focuses on rapid layer height changes to facilitate liquid deposition within regions with low contact angles. Finally, a layer height gradient was systematically established within the mold, resulting in a wettability gradient surface capable of controlling the movement of water droplets across the surface. The performance of these functional surfaces was successfully validated using various experimental methods. This study introduces a manufacturing technique based on changing layer heights within the framework of material extrusion-type 3D printing technology. A wide range of intricate and diverse functional surfaces can be produced by extending the manufacturing method proposed in this study to 3D printing technologies beyond the scope of material extrusion type 3D printing.

LLDPE/TiO2 composites with high UV aging resistance and mechanical properties by controlling the alumina coating on TiO2

AbstractFor preparing high performance LLDPE film, the photocatalytic activity and the UV absorption capacity of TiO2 were regulated by the alumina coating content on the surface of TiO2. Alumina‐coated TiO2 was prepared by the chemical liquid deposition method, and characterized by element analysis, TGA, FTIR, and morphology observation. The alumina coating layer had been proven to covalently bind to the surface of TiO2 through AlOTi bonds, which formed a continuous and dense coating layer, followed by forming a loose flocculent coating layer with the increase of alumina content. The alumina coating layer could significantly reduce the formation of carbonyl group on the LLDPE chains, and enhance UV aging resistance of LLDPE by inhibiting the photocatalytic activity of TiO2. Moreover, the dispersion of alumina‐coated TiO2 in the LLDPE matrix was improved. Thus, the transmittance of LLDPE/alumina‐coated TiO2 composites was reduced and the whiteness was improved. Importantly, the continuous and dense alumina coating layer was enough to inhibit the photocatalysis effect of TiO2 on LLDPE. The further increase of alumina coating content reduced the UV absorption capacity of alumina‐coated TiO2 and its compatibility with the LLDPE matrix. Therefore, the best alumina coating content on the surface of TiO2 was 1.46 wt% for preparing high performance LLDPE/TiO2 composites.Highlights Alumina‐coated TiO2 with controllable coating thickness was successfully synthesized. LLDPE/alumina‐coated TiO2 has excellent UV aging resistance and mechanical properties. The photocatalytic activity and UV absorption capacity of TiO2 could be regulated. 1.46 wt% of alumina coating is the best content for high performance LLDPE/TiO2 composites.

Visualization and quantitative evaluation of aerosol deposition using 3D-printed adult nose cavities

Local steroid medication is one of the most important treatment options for chronic rhinosinusitis. Regional deposition has a higher clinical value compared with total deposition in predicting treatment outcomes or evaluating adverse reactions. The goal of this project is to propose an effective technique for visualizing and quantifying aerosol deposition in a three-dimensional adult nasal cavity, and to verify the practicality of this method. Three-dimensional (3D) nasal cavity models were constructed from computed tomography (CT) scans of one post-operative rhinosinusitis subject using imaging software. The nasal cast was coated with a water-indicating paste and deposited with saline; a liquid dressing was added to visualize the progress. The quantity of liquid dressing was evaluated via HPLC and the liquid deposition was analyzed within the nasal cast cavity. Herein, 98.77% of the particles generated by the nebulizer were over 5 μm, suggesting that most of the aerosol could effectively enter the nasal cavity instead of the lower respiratory system. The liquid dressing was mainly deposited in the nasal cavity, ethmoid sinus, and frontal sinus according to the visualization tests. HPLC results suggested that the main deposits were the frontal sinus (up to 41.80%) as well as in the sphenoid sinus and ethmoid sinus (14.00%). The large particle nebulizer (BM-TCA) generally led to better deposition in sinus areas when compared to the smaller particle nebulizer (PARI). This technology allows for in vitro testing of various types of nasal preparations and equipment under various test methods.

Stearic Acid Modified Nano-ZnO Superhydrophobic Coating for Steel Mesh

Abstract To mitigate the detrimental effects of water on metal textiles, hydrophobic modification of such materials has garnered significant attention. However, traditional approaches often rely on complex procedures or costly materials, limiting their widespread application. Herein, we present a facile method for fabricating a superhydrophobic coating on steel mesh, and characterize the properties of the modified material. Initially, the surface of the dry steel mesh is uniformly coated with nano-ZnO crystals using a liquid deposition technique at room temperature. Subsequently, stearic acid is employed to hydrophobically modify the ZnO crystals, yielding a ZnO-based superhydrophobic coating. The influence of ZnO concentration and deposition duration on the surface crystal structure, hydrophobicity, and abrasion resistance is investigated. X-ray diffraction (XRD) analysis is performed to study the surface groups before and after hydrophobic modification, while static contact angle measurements are used to assess the hydrophobic properties of the coated surface. Remarkably, even after abrasion with 1000-mesh sandpaper, the superhydrophobic properties of the steel mesh with an optimized ZnO concentration decrease by only 4%. This simple, cost-effective, and highly efficient preparation method holds promising potential for applications in related fields.

Copper stearate-coated DAP-4 core–shell composites for enhanced safety and thermal decomposition performance

In this study, DAP-4@copper stearate (CS) core–shell composites were fabricated by an in situ synthesis and liquid deposition using CS as the catalyst. In addition, a comprehensive characterization was conducted on the morphology, structure, thermal decomposition, and safety performance of the acquired samples. The results revealed that DAP-4@CS composites with a complete, compact core–shell structure. During thermal analysis experiments, DAP-4@CS (5, 10, 15, and 20 wt%) resulted in a reduction in the thermal decomposition peak temperatures (Tp) by 35.22, 55.02, 68.22 and 73.76 °C respectively when compared with DAP-4, and their corresponding activation energy values decreased by 61.22, 87.3, 63.62, and 69.54 kJ/mol. Notably, the DAP-4@CS composites with 5 wt% and 10 wt% CS exhibited increased heat release by 1291.03 and 1546.8 J/g, respectively. The H50 value for DAP-4 increased from an initial value of 44.67 cm to an improved value of 64.57 cm, while its friction sensitivity increased from 30 N to 40 N during safety experiments. Moreover, we propose the principle of thermal decomposition catalysis and desensitization of CS for DAP-4. The above research results provide a new solution to the contradictions and obstacles in the application of DAP-4 as an oxidizer in fuel.

Enhancing Clay-Based 3D-Printed Mortars with Polymeric Mesh Reinforcement Techniques.

Additive manufacturing (AM) technologies, including 3D mortar printing (3DMP), 3D concrete printing (3DCP), and Liquid Deposition Modeling (LDM), offer significant advantages in construction. They reduce project time, costs, and resource requirements while enabling free design possibilities and automating construction processes, thereby reducing workplace accidents. However, AM faces challenges in achieving superior mechanical performance compared to traditional methods due to poor interlayer bonding and material anisotropies. This study aims to enhance structural properties in AM constructions by embedding 3D-printed polymeric meshes in clay-based mortars. Clay-based materials are chosen for their environmental benefits. The study uses meshes with optimal geometry from the literature, printed with three widely used polymeric materials in 3D printing applications (PLA, ABS, and PETG). To reinforce the mechanical properties of the printed specimens, the meshes were strategically placed in the interlayer direction during the 3D printing process. The results show that the 3D-printed specimens with meshes have improved flexural strength, validating the successful integration of these reinforcements.

Recent Trends in Tailoring External Acidity in Zeolites for Catalysis.

Zeolites are crystalline aluminosilicates with well-defined microporous structures that have found several applications in catalysis. In recent years, great effort has been devoted to defining strategies aimed at tuning structural and acidity properties to improve the catalytic performance of zeolites. Depending on the zeolitic structure, the acid sites located inside the crystals catalyze reactions by exploiting the internal channel shape-selectivity. In contrast, strong acid sites located on the external surface do not offer the possibility to control the size of molecules involved in the reactions. This aspect generally leads to a loss of selectivity toward desired products and to the uncontrolled production of coke. Passivating surface acidity is a promising way to overcome deactivation issues and to enhance the catalytic performance of zeolites. This Mini-Review aims to provide, for the first time, a complete overview of the techniques employed in recent years to neutralize strong external acid sites. Both chemical and liquid vapor deposition of silicates have been widely employed to passivate the external surface acidity of zeolites. In recent years, the epitaxial growth of layers of aluminum-free zeolite, e.g., silicalite-1, over the surface of the acidic zeolite has been proposed as a new approach to neutralize strong external acid sites controlling diffusional phenomena. NH3-TPD, FT-IR, SEM-EDX, and other techniques have been used to provide information about the level of control of the external strong acidity of passivated zeolites. In this Mini-Review, both passivation treatments and characterization techniques are compared and advantages and disadvantages deeply discussed to elucidate the effect of passivation procedures on physical features and especially the catalytic behavior.

Efficient synthesis of durable superhydrophobic SiO2@PFDMS coatings on bamboo by liquid deposition

Fast-growing bamboo offers a sustainable alternative to meet the increasing demand for wood. However, its inherent hydrophilicity limits its performance, necessitating hydrophobic modifications to enhance longevity. In this study, 1 H,1 H,2 H,2 H- perfluorodecyltrimethoxysilane was used to anchor SiO2 nanoparticles onto bamboo surface, creating superhydrophobic coatings. The nanoparticles constructed a micro-/nano-rough structure on the bamboo surface, and fluorosilanes significantly reduced the surface energy of bamboo. The wettability, micro-morphology, chemical composition, and resistance to acid and alkali corrosion, mechanical abrasion, and UV aging of the superhydrophobic coatings were extensively investigated. The results demonstrated that the modified bamboo achieved a surface energy of 0.2±0.0 J/m2 and a water contact angle of 156.8±0.2°. Furthermore, the coating exhibited excellent chemical and physical stability. This straightforward and effective surface treatment method offers substantial potential for broadening bamboo's applications in outdoor environments.

Anti-corrosive and carbonyl-rich interlayer enables highly reversible zinc anode

Aqueous zinc ion batteries (AZIBs) are considered as highly promising candidates for large-scale energy storage due to their exceptional safety profile, environmental sustainability, and cost-effectiveness. However, the progress of AZIBs is impeded by several challenges including the formation of zinc dendrites, self-corrosion issues, and hydrogen evolution. Herein, we demonstrate the in-situ fabrication of a hydrophobic and carbonyl-rich zinc phthalate (ZCHO) solid electrolyte interphase (SEI) layer on the zinc foil through a facile liquid deposition method. The incorporation of carbonyls into the ZCHO layer enhances ion migration dynamics by attracting Zn2+, while also promoting preferential deposition onto the (002) surface, effectively mitigating water-induced corrosion and hydrogen evolution, likewise reducing charge transfer resistance. These inherent advantages contribute to a homogeneous distribution of Zn2+ concentration on the zinc anode surface, thereby suppressing dendrite growth. The results demonstrate that the symmetric battery exhibits an impressive cycle life of over 2300 h under a current density of 1 mA cm−2, with an areal capacity of 0.5 mAh cm−2. Additionally, it demonstrates stable cycling for more than 700 h at 5 mA cm−2, 0.25 mAh cm−2. Furthermore, when assembled with NH4V4O10, the full battery delivers a specific capacity of 222.9 mAh g−1 after undergoing 1000 cycles under a current density of 5 A g−1 while maintaining a capacity retention rate of 86.26 %. This study presents a novel and facile approach to advance research on high-performance AZIBs.

Core‐Shell Zeolite with Confined Nickel Particles as Prominent Catalyst for the Hydrogenation of Maleic Anhydride

AbstractTransformation of maleic anhydride (MA) into succinic anhydride (SA) through the development of high‐performance catalysts is an appealing approach from a sustainable development perspective. Herein, a core‐shell catalyst with silicate‐1 supported and MCM‐41 encapsulated nickel was prepared, which exhibited extraordinarily high MA conversion (99.8 %) and SA selectivity (99.9 %). Detailed structural characterizations and catalytic evaluation demonstrated that the core‐shell catalyst derived from the liquid deposition method is a hierarchically porous material with tunable shell thicknesses, possessing strong interaction between Ni particles and the supports. Key to this success is the MCM‐41 shell that covered the defects such as silanol nests on the surface of the silicate‐1 zeolite, diminishing both the surface and intra‐particle diffusion barriers, thus the specially‐designed catalyst achieved high activity under rather mild conditions (100 °C, 3.0 MPa), which is 59 % higher than the conventional silicate‐1 supported Ni catalyst. Furthermore, the mesoporous MCM‐41 shell plays a crucial role in minimizing the leaching and sintering of Ni particles, thereby bolstering catalytic stability. Overall, the research provides a new approach for the rational design to optimize the performance of hydrogenation catalysts and introduces a novel idea to enhance the activity and stability of Ni‐supported catalysts.

Conversion of C8 aromatics over a dual-bed catalyst.

A dual-bed catalyst was prepared for the conversion of C8 aromatics. The upper bed layer consisted of ZSM-5 covered with SiO2, primarily utilized for ethylbenzene dealkylation. By employing tetraethyl orthosilicate (TEOS) as a deposition agent through the chemical liquid deposition (CLD) method, the modified ZSM-5 catalyst exhibited optimal catalytic performance at a TEOS addition of 0.6 g per gram of catalyst. The lower bed layer contained ZSM-39 catalyst, mainly employed for xylene isomerization reaction. ZSM-39 was synthesized using pyrrolidine as the template, and the best catalytic performance was achieved when the OH-/SiO2 molar ratio in the synthesis system was 0.05. The mass ratio between the upper and lower agents was maintained at 1 : 1. Compared to traditional single-bed ZSM-5 catalysts, the dual-bed catalyst demonstrated enhanced activity and selectivity.

Modeling and simulation of air-water upward annular flow characteristics in a vertical tube using CFD

Annular flow refers to a special type of two-phase flow pattern in which liquid flows as a thin film at the periphery of a pipe, tube, or conduit, and gas with relatively high velocity flows at the center of the flow section. This gas also includes dispersed liquid droplets. The liquid film flow rate continuously changes inside the tube due to two processes-entrainment and deposition. To determine the liquid holdup, pressure drop, the onset of dryout, and heat transfer characteristics in annular flow, it is important to have proper knowledge of flow characteristics. Especially a better understanding of entrainment fraction is important for the heat transfer and safe operation of two-phase flow systems operating in an annular two-phase flow regime. Therefore, the objective of this work is to develop a computational model for the simulation of the annular two-phase flow regime and assess the various existing models for the entrainment rate. In this work, Computational Fluid Dynamics (CFD) in ANSYS FLUENT has been applied to determine annular flow characteristics such as liquid film thickness, film velocity, entrainment rate, deposition rate, and entrainment fraction for various gas-liquid flow conditions in a vertical upward tube. The gas core with droplets was simulated using the Discrete Phase Model (DPM) which is based on the Eulerian-Lagrangian approach. The Eulerian Wall Film (EWF) model was utilized to simulate liquid film on the tube wall. Three different models of Entrainment rate were implemented and assessed through user-defined functions (UDF) in ANSYS. Finally, entrainment for fully developed flow was determined and compared with the experimental data available in the literature. From the simulations, it was obtained that the Bertodano correlation performed best in predicting entrainment fraction and the results were within the ±30 % limit when compared to experimental data.

A comprehensive bench-to-bed look into the application of gamma-sterilized 3D-printed polycaprolactone/hydroxyapatite implants for craniomaxillofacial defects, an in vitro, in vivo, and clinical study

This study investigates the safety and efficacy of 3D-printed polycaprolactone/hydroxyapatite (PCL/HA) scaffolds for patient-specific cranioplasty surgeries, employing liquid deposition modeling (LDM) technology. This research is pioneering as it explores the impact of gamma radiation on PCL/HA scaffolds and utilizes printing ink with the highest content of HA known in the composite. The mechanical, morphological, and macromolecular stability of the gamma-sterilized scaffolds were verified before implantation. Subsequent research involving animal subjects was conducted to explore the effects of sterilized implants. Eventually, three clinical cases were selected for the implantation studies as part of a phase 1 non-randomized open-label clinical trial. It was shown that a 25 kGy gamma-ray dose for sterilizing the printed implants did not alter the required geometrical precision of the printed implants. The implants exhibited well-distributed HA and strength comparable to cancellous bone. Gamma radiation reduced hydrophobicity and water uptake capacity without inducing pyrogenic or inflammatory responses. Personalized PCL/HA substitutes successfully treated various craniomaxillofacial defects, including trauma-induced facial asymmetry and congenital deformities. HA nanoparticles in the ink stimulated significant osteoconductive responses within three months of implantation. Moreover, the results revealed that while larger implants may exhibit a slower bone formation response in comparison to smaller implants, they generally had an acceptable rate and volume of bone formation. This clinical trial suggests the application of a sterilized PCL/HA composite for craniomaxillofacial surgery is safe and could be considered as a substitute for autologous bone.

Influence of electric field, liquid film thickness, and sodium chloride deposition on atmospheric corrosion of Cu

Printed circuit boards (PCBs) are prone to failure due to the influence of environmental factors such as humidity, salt spray, and electric fields during usage. As the lead pitch of PCBs decreases and these environmental factors become challenging to control, corrosion becomes unavoidable. This study used a self-built thin liquid film–electric field coupling environment in an in situ electrochemical testing apparatus. PCB-Cu electrodes were evaluated using open-circuit potential and polarization curve tests on the thin liquid film. This study systematically investigated the effects of external electric field bias, sodium chloride deposition, and liquid film thickness on PCB-Cu corrosion. The results showed that increased bias promoted Cu corrosion in the coupled environment and altered electrode reactions. The cathodic process transitioned from activation control at 0–1 V to hydrogen evolution electrochemical control at 3 V for electrode reactions. Increased sodium chloride deposition enhanced the Cu corrosion rate in the coupled environment primarily due to Cl− damaging the corrosion product film. Under different liquid film thickness conditions, the corrosion rates can be ranked as 200 μm > 300 μm > 100 μm, with 200 μm exhibiting the highest corrosion rate and marking the transition point from the cathodic to anodic control of the corrosion reactions. Orthogonal analysis results indicated that bias was the most influential factor affecting Cu corrosion, followed by liquid film thickness and sodium chloride deposition.