Sprayed Films Research Articles

Agent-based modeling system for real-time characterization of film thickness in digital twin coating

In the automated spraying workshop of ship segments, poor visibility caused by dust and fog hampers the effectiveness of the video monitoring system. The traditional method used during the automated spraying process fails to provide real-time measurement of film thickness and prediction of spraying quality, resulting in uneven film thickness and high rework rates. Robotic spraying technology also faces challenges, such as the time-consuming and labor-intensive process of building and computing a highly reliable Computational Fluid Dynamics (CFD) based spraying film-forming simulation model, which cannot be reflected in real-time during the spraying process. The digital twin characterization method, based on the agent model, offers a solution to these limitations and challenges, providing new ideas and approaches for improving and optimizing the spray film formation model. This paper presents the development of a real-time characterization system for sprayed film thickness based on digital twin technology. The spraying film thickness under different working conditions is obtained using Ansys-Fluent simulation software by varying the gun height and gun speed. The predictive model for spraying film thickness is then established using the obtained simulation data and the corresponding gun height and gun speed, employing the surrogate modeling method (BP neural network). The real-time characterization system for spraying film thickness is developed by combining C# and Unity3D. Finally, in order to ensure the accuracy of the predictive model, a spraying experimental platform is built to verify the accuracy of the predictive model.

Numerical Investigation of Film Formation Characteristics and Mechanisms through Airless Spraying on Spherical Surfaces

This paper focuses on key engineering issues, particularly the overall turbulent transport of paint spray and coating film distribution characteristics, in the process of airless spraying film formation. By deeply considering the geometric features of spherical surfaces and their impact on the near-wall region of the flow field, an airless spraying film formation model consisting of the Eulerian multiphase model, the realizable k–ε turbulence model, and the Eulerian Wall Film model was established. Through numerical simulations of static spraying on the inner and outer walls of spherical surfaces with different radii, the influence of geometric features on the spray flow field and film formation characteristics on spherical surfaces was investigated. Subsequently, based on numerical simulations of dynamic spraying on different nozzle trajectories, the film formation characteristics were analyzed, and the optimal spray trajectory planning method was determined. Additionally, this study examined the coating distribution characteristics during dynamic spraying on spherical surfaces with varying geometric dimensions. Finally, a kind of chlorinated rubber anti-corrosion primer was chosen to carry out spraying experiments, which validated that the airless spray coating model and the corresponding numerical simulation methods established in this paper were reasonable and feasible for investigating the film formation characteristics on spherical surfaces. This work is expected to further promote the application of airless spray techniques in machinery, automotive, shipbuilding, and aviation industries.

A novel coaxial air-R134a spray cooling for heat transfer enhancement of laser dermatology

Efficient cooling is essential in laser dermatology to prevent thermal damage, but current methods are often hindered by thermal barrier film deposition. This study presents coaxial air-R134a spray cooling for heat transfer enhancement and deposited-film mitigation. Surface temperature was measured using a TFTC thermocouple, while heat flux was estimated through the improved Duhamel theorem. High-speed camera visualization with the Mie-scattering technique captured the spray and film behavior. The results showed uniform and effective cooling via transient surface heat transfer and film behaviors. The boiling curve identified three distinct cooling phases: transition boiling, nucleate boiling, and single-phase film deposition. Airflow adjustments not only enhance the heat transfer coefficient but also control spray dynamics, droplet rebounding, and film spreading. Self-organizing maps revealed that medium-to-high nozzle spacing (y/D) reduces surface temperature and increases the heat transfer coefficient. Film resistance time is minimized by either high airflow and low y/D or low airflow and high y/D. For critical heat flux, low y/D and airflow are optimal. A y/D = 32 and 60 L/min airflow provided appropriate operating conditions. However, airflow increased frost deposition during off-duty, suggesting moisture-free air in the future.

A Toluene-induced Infundibulo-neurohypophysitis: A New Cause of Hypophysitis Secondary to Toxic Exposure.

Hypophysitis is a rare inflammatory disorder of the pituitary gland. Symptoms and signs of hypophysitis can be various, and its recognition may be challenging. Arginine vasopressin deficiency (AVP-D) due to exposure to a variety of drugs and toxic substances is rare, but some cases have been reported. Only 2 cases of AVP-D following toxic exposure to toluene, an aromatic hydrocarbon, have been reported in the literature. To our knowledge, our case represents the first description of an infundibulo neurohypophysitis (INH), manifested with AVP-D, secondary to inhalation of toluene. A 59-year-old man with an unremarkable medical history was referred to our department for headache, polyuria, and polydipsia after the inhalation of spray film containing toluene. The blood tests revealed a hyperosmolar plasma hypernatremia with normal kidney function. A desmopressin test was performed, with an improvement in water balances, blood electrolytes, and diuresis contraction. A pituitary MRI detected the absence of a normal hyperintense signal of the neuro-pituitary in the T1-weighted images. In consideration of the clinical signs and radiological imaging suggestive of INH, a therapy with desmopressin and corticosteroids was instituted, with gradual improvement of polyuria and resolution of the radiological features of INH. The exceptional finding of INH, manifested with AVP-D, following toluene inhalation could represent a new secondary cause of hypophysitis. The possibility that drugs or toxic substances never reported before could induce INH should not be excluded since the study on hypophysitis is relatively recent but emerging, predictably destined to increase exponentially in the coming years.

Research on Film Formation Characteristics by Spraying on Unidiameter Vertical Interpenetrating Cylindrical Surfaces

Unidiameter Vertical Interpenetrating Cylindrical Surfaces (UVICS, also called T-pipe surfaces) are a type of typical complex surface that exists in facilities or equipment such as oil storage tanks and industrial pipelines. The shape and surface characteristics of a component undergoing spraying will have a significant impact on the spray flow field and the resulting coating film. In order to optimize the coating effects of complex surfaces, the Euler-Euler approach was utilized to model a spray film formation process that encompasses both a spray flow field model and a wall adhesion model. Subsequently, the influence of the geometric features, geometric dimensions, lateral air pressure of the spray gun, and spraying distance on the coating film characteristics of this kind of surface were systematically investigated. It is determined that the film thickness uniformity could be enhanced by decreasing the dimensions of the workpiece or increasing the lateral air pressure and spraying distance in an appropriate manner when spraying at the location with the most complex geometric features of UVICS. Furthermore, the optimal parameters under varying spraying conditions were identified. The experiments validated the accuracy of the numerical simulation results and demonstrated the feasibility of this simulation model. The study is of significant value in addressing the challenges associated with film formation during spraying on complex surfaces, developing a comprehensive theoretical framework for air spraying, and expanding the scope of applications for automatic spraying technology.

Study of Humic Acid Organic Liquid Mulching Film on Promoting Green Agriculture Development

Mulching film is an important measure to promote agricultural production income and increase, the current widely used plastic mulching film has high stability, difficult to decompose, resulting in "agricultural white pollution", the development and application of degradable mulching film has become a solution. This case focuses on the study of organic multifunctional liquid mulching film with humic acid as the main raw material, which plays a unique role in promoting biological activity and soil improvement, the application of "liquid" spray film, the integration of fertilizer, pesticides, mulching film in one multi-functional comprehensive effect, to clarify its functional characteristics, alternative feasibility and the promotion of green agricultural development, and put forward the existing problems and countermeasures. This paper provides technical support and practical demonstration for the elimination of exogenous pollutants in farmland, and looks forward to the broad application prospects of this liquid mulch film in environmental protection and other aspects.

Improving photocatalytic performance: Creation and assessment of nanostructured SnO2 thin films, pure and with nickel doping, using spray pyrolysis

This study investigates conductive, transparent films of undoped and Ni-doped SnO2 deposited through water solvent spray pyrolysis, aiming to combat environmental water pollution. Examining these films using X-ray diffraction (XRD), Fourier transform infrared absorption microscopy (FTIR), UV–Vis spectrophotometer, and Hall effect, the research focuses on photocatalytic degradation kinetics using rhodamine B (RhB) as a model pollutant from the textile industry.XRD results confirm tetragonal structures of SnO2 and Ni: SnO2 films with crystallite sizes ranging from 21.83 to 19.52 nm. The sprayed films exhibit resistivity variations (7.1 × 10−3 to 4.5 × 10−3) Ω.cm and figure of merit variations [(1.49 × 10−4 to 25.03 × 10−4); (2.69 × 10−4 to 9.1 × 10−4)] (Ω/sq)−1. Optical properties include ∼73% light transmission, ∼20% reflection, and ∼7% absorptance, with porosity (8.65–11.44)%, refractive index (2.88–1.57), extinction coefficient (0.0043–0.0013), dielectric constants (8.31–2.48 and 0.025–0.0041), optical density [(3.9 × 10+10–7.86 × 10+09) S−1], skin depth [(2.06 × 10−3–6.7 × 10−3) cm−1], and optical band gap with Urbach energy [(3.8–3.6) eV and (0.67–0.43) eV] obtained at 550 nm.The photocatalytic process, crucial for water pollution treatment, exhibits pH sensitivity (12.3–1.7) over varied times (0–90 min) and is influenced by the SnO2 thin film elaboration method. Notably, 0.5 M-concentration SnO2 films show the most efficient photocatalytic degradation rates. This research highlights the potential of SnO2 in environmentally friendly water pollution treatment, emphasizing its practical application in addressing crucial environmental challenges.

Numerical simulation and experimental study of dip angle spray film thickness under elliptical double Gaussian sum model

To address the problem of modeling the growth rate of coating film thickness when spraying at inclination angle, based on Gaussian sum model, it is proposed to use the elliptic double Gaussian sum model to establish the cumulative model of coating film thickness when spraying at static inclination angle of the spray gun. The differential geometry amplification theorem is used to establish the coating growth rate model with the spraying inclination angle as the variable; after that, the static inclination spraying experiments are carried out, and the coating thickness data of the sampling points are recorded through the spraying experiments, and the Levenberg-Maquart algorithm is used for the least-squares fitting of the model, which results in the static spraying film thickness distribution model. Finally, compared with the elliptic double β model, the fitting accuracy of the elliptic double Gaussian sum model is 6.3% higher than that of the elliptic double β model when spraying at inclination angle by comparing the R-square values, and the elliptic double Gaussian sum model is more capable of obtaining a better fitting accuracy, which further confirms the validity and practicability of the model.

Dynamic Numerical Simulation of Curved Surface Coating Trajectory Based on STL Slicing Algorithm

The thickness of the coating on the surface of a workpiece is an important factor in determining the quality of spraying. However, it is challenging to estimate the distribution of film thickness accurately before the actual spraying process. This lack of estimation hinders the optimization of spraying process parameters and trajectory. To overcome this, a numerical simulation of surface spray coating thickness was conducted to provide guidance for the actual coating process. The research consists of three main parts. Firstly, the spray trajectory of the spray gun is determined using the proposed Stereo Lithography (STL) model slicing algorithm. Secondly, a two-phase flow spray model and collision adhesion model are established to construct the spray film model. The surface mesh is determined, and the spraying process parameters are set. Finally, numerical simulation is conducted to analyze the dynamic spraying trajectory and the distribution of coating thickness. The results show that the coating thickness distribution on an arc surface is thicker in the middle and thinner on the edges. The distribution is symmetric with respect to both the transverse and longitudinal directions of the arc surface. The coating thickness distribution at both ends is not as uniform as in the middle section. The concave part of the free surface has the largest coating thickness, while the coating thickness distribution on the convex part is not as uniform as on the relatively flat part. This method of simulating the coating thickness distribution on complex surfaces provides a solid foundation for further optimization of spraying process parameters and trajectory, ultimately improving the qualification rate of workpiece spraying processing.

Exploring the photocatalytic potential of copper iodide thin films deposited via multiple spray technique

This study explores the optimization of deposition parameters for CuI thin films, and investigates their potential application as photocatalysts. γ-CuI thin films were grown on glass substrate using the nebulized spray method at different substrate temperatures. Structural, morphological, and optical studies of the films were carried out. The substrate temperature was found to have a profound influence in determining the aforesaid properties of the films. As seen from scanning electron micrographs, the morphology of the films varied from discontinuous to uniform, and then to being agglomerated, when substrate temperature was increased from 50 °C to 175 °C. At the same time, it was observed from x-ray diffraction studies that films with better crystallite size was formed at lower temperatures. To obtain films with good crystallinity as well as continuous morphology, multiple spraying was carried out which involve repeating the deposition process manifold on the same substrate. Systematic characterization showed that multiple spraying at low temperatures resulted in uniform films with good crystallinity. The photocatalytic activity of single, double and triple sprayed CuI thin films prepared by nebulized spray method under visible light irradiation was also investigated. All of the films exhibited photocatalytic activity in the visible spectral region, with the triple-sprayed CuI thin film exhibiting the greatest efficiency in the photocatalytic degradation of Methylene blue.

Experimental study on alkali reduction of film-coated porous ecological concrete by microbial calcium carbonate precipitation technology

Some plants do not grow due to the high pH levels of ecological concrete pore solutions. In this paper, we design and build an integrated device featuring a combined microbial film and a transverse/U-shaped grouting film. We have applied to the China Intellectual Property Office for an invention patent on this device. The device overcomes the blockage of the grouting port caused by microbial and vertical grouting. The vertical grouting tube leaves holes inside a specimen, reducing the compressive strength, while the integrated device optimizes and decreases variation in the recycling of microbial bacteria. The reduction in the pore alkalinity of porous ecological concrete resulting from the microbial grouting film of this device is larger than that resulting from a microbial sprayed film. The pH values of porous ecological concrete with microbial grouting films and microbial sprayed films are obtained by the pure slurry soaking method and solid–liquid extraction method, respectively. The pH value is lower for the film obtained by the pure slurry soaking method than for that obtained by the solid–liquid extraction method. Conversely, the pH value of porous ecological concrete with a microbial grouting film is reduced to approximately 8 at an age of 56 days. The compressive strengths of the porous ecological concrete specimens with the two films are almost the same. The results of this study provide the necessary theoretical basis for developing alkali reduction technology for porous ecological concrete with environmental and economic benefits.

Highly responsive and selective ozone sensor based on Ga doped ZnS-ZnO composite sprayed films.

Ozone detection is currently the subject of wide scientific and technological research, motivated by its harmful impact on human safety, environment and health. With the aim of searching for new highly sensitive materials for ozone detection, Ga-doped ZnS and ZnS-ZnO films were deposited by a spray pyrolysis technique. The obtained films were annealed at 400 °C for two hours. The ozone sensing properties were investigated by measuring the sensor resistance for several ozone concentrations ranging from 30 to 120 ppb. The sensor response reveals a dependence on the gallium concentration. The best response was obtained with 4% doping gallium. The sensitivity is 4.5 ppb-1 at 260 °C and the response to 30 ppb ozone is 150. Moreover, the sensor shows high performance such as good selectivity and fast rapidity.

A Review of the Developments of the Characteristics and Mechanisms of Airless Spraying on Complex Surfaces

The special surface appearance of complex surfaces restricts the coating film quality of spraying. The study of the atomization and film formation characteristics of typical complex surfaces, as well as the spraying mechanism, is essential for planning the spraying robotic trajectory and improving the spraying efficiency. In this paper, modeling and characteristics of the atomization and film formation process, based on CFD numerical simulations in previous studies, are systematically reviewed, focusing especially on airless spraying. In addition, the advantages and disadvantages of the existing research from the perspective of numerical models and methods are discussed. Finally, a further research direction for spraying on complex surface is prospected. Overall, a comprehensive and up-to-date review of spray atomization and film formation characteristics is considered valuable to practitioners and researchers in these fields, and will facilitate the further application of robotic spraying in the mechanical, automotive, marine, aerospace, petrochemical and other industries.

Wound healing efficacy of a polymeric spray film solution containing Centella asiatica leaf extract on acute wounds

Objective: To study the clinical efficacy of a polymeric spray film containing Centella asiatica extract to heal acute wounds. Method: A polymeric spray film solution for wound healing was formulated using Centella asiatica extract, which contained triterpenes, including asiatic acid, madecassic acid, asiaticoside and madecassoside. The stability and physicochemical properties of the formulation were evaluated, and a multicentre, randomised, controlled trial was conducted to assess its clinical wound-healing efficacy. The Pressure Ulcer Scale for Healing (PUSH Tool) score was used to evaluate wound healing on days 0, 3, 5 and 7. Results: The cohort consisted of 60 volunteers with clean-contaminated wounds (class 1), randomly assigned to the Control (n=30) and Testing (n=30) groups. The spray product contained asiatic acid, madecassic acid, asiaticoside and madecassoside at 0.20±0.02mg/ml, 0.16±0.01mg/ml, 0.32±0.03mg/ml and 0.10±0.00mg/ml, respectively. The pH value was 5.5±0.01, and the viscosity was 33±4cP. The product was stable for six months when stored at 30±2°C and at 40±2°C, in 75±5% relative humidity. The tested product significantly reduced the total PUSH and exudate scores, indicating that the polymeric spray film solution containing Centella asiatica improved wound healing. The average healing recovery times for the Testing and Control groups were 4.6±1.1 days and 4.87±1.0 days, respectively. Conclusion: In this study, Centella asiatica extract-containing polymeric spray film solution was beneficial as an acute wound medication, which could shorten healing time with no adverse effects.

Experimental Study on Macroscopic Spray and Fuel Film Characteristics of E40 in a Constant Volume Chamber

In the modern industrial field, there is a strong emphasis on energy-saving and emission reduction. Increasing the amount of ethanol in ethanol–gasoline blends has the potential to replace fossil fuel gasoline more effectively, improving energy efficiency and lowering emissions. The interaction between liquid fuel film generation on the piston crown and spray impingement in the combustion chamber in the setting of GDI engines has a substantial impact on particle emissions and engine combustion. In this study, 92# gasoline and ethanol by volume are combined to create the ethanol–gasoline blend E40. The spray characteristics and film properties of both gasoline and the intermediate proportion ethanol–gasoline blend E40 were researched utilizing a constant volume combustion platform and the schlieren method and refractive index matching (RIM) approach. The results show that, for 0.1–25 operating conditions, gasoline consistently displays greater macroscopic spray characteristic parameters than E40. This shows that gasoline fuel spray evaporation is superior to E40. Similar results are seen in the analysis of wall-attached fuel films, where the volume and thickness of the gasoline film are less than those of the E40 film under the given operating conditions. In contrast, E40 consistently exhibits stronger macroscopic spray characteristic values than gasoline under the 0.1–150 and 0.4–150 operating conditions, along with lower film thickness and volume. As a result, under these two operating conditions, E40 fuel performs better during spray evaporation.

FORMULASI FILM FORMING SPRAY DARI KLORAMFENIKOL UNTUK LUKA

The wound healing process should be short so as not to interfere with productivity and reduce costs. SFFS (spray film forming system) is a combination of transdermal preparations in which a polymer solution is sprayed onto the skin and will form an almost transparent film by evaporation of the solvent. Film-forming solutions are particularly advantageous for transporting the active substance to the site of action by the shortest route in cases of dermal or lower tissue infections. Chloramphenicol is a lipophilic drug so it penetrates the skin well because the stratum corneum matrix is ​​also lipophilic. The purpose of this study was to make a formulation of a sprayed chloramphenicol film-forming solution in order to obtain the best formula and increase effectiveness. The research was carried out on an experimental basis and three formulas were prepared with different polymer concentrations. The results of the study obtained a film-forming spray for each formula with a film formed that was flexible and adhered well to the skin, with a pH of 6. The time needed to make the film layer in skin is 0.87-1.19 minutes with an average dose weight of spray is 61.33-85.33 mg.

Improvement of Temperature Distribution Uniformity of Ready-to-Eat Rice during Microwave Reheating via Optimizing Packaging Structure.

The taste quality of ready-to-eat rice is influenced by the uniformity of temperature distribution during microwave reheating. The temperature distribution uniformity of ready-to-eat rice loaded in a rectangular lunch box is investigated under microwave reheating. The results show that with a 10-80 °C temperature increase in the ready-to-eat rice, the thermal conductivity increases, dielectric constant, and specific heat increase and then decrease, while the dielectric loss factor decreases and then slightly increases. The microwave-heating process of ready-to-eat rice exhibits a clear 'corner effect', and the observed 'hot spot' results in poor temperature uniformity in ready-to-eat rice. A metalized packaging structure design is subsequently proposed to ameliorate the temperature non-uniformity. According to comparative results of four metalized packaging forms, the spray film volume and film thickness corresponding to film volume are developed as 3.5×10-4 mL/mm2, 0.30 mm, respectively, which levels off the difference in temperature to improve the temperature distribution uniformity of ready-to-eat rice by microwave reheating.

Research on the Analysis and Application of Polymer Materials in Contemporary Sculpture Art Creation.

The application of polymer materials in sculpture art creation is extensive and plays a significant role in the development of sculpture art. This article aims to systematically explore the application of polymer materials in contemporary sculpture art creation. The research comprehensively applies various techniques such as literature research, data comparison, and case analysis to explore in detail the ways, methods, and paths of polymer materials employed in the shaping, decoration, and protection of sculptural artworks. First, the article analyzes three methods of shaping sculpture artworks with polymer materials (casting, printing, and constructing). Secondly, it explores two techniques of using polymer materials to adorn sculpture artworks (coloring and imitating texture); then it discusses the significant approach of using polymer materials to protect sculptural artworks (protective spray film). Finally, the research identifies the merits and demerits of using polymer materials in contemporary sculpture art creation. The findings of this study are expected to enrich the effective application of polymer materials in contemporary sculpture art creation and offer novel techniques and ideas for contemporary sculpture art creators.

Investigations of spray-deposited NiO thin films for ultrasensitive formaldehyde detection

Formaldehyde detection in the environment is the most important due to its carcinogenic effects on human health. In this study, we present the synthesis of nickel oxide (NiO) films at various substrate temperatures with a cost-effective spray pyrolysis technique. Deposited thin films are investigated for micro-structural, topographical, optical and formaldehyde sensing characteristics. According to XRD analysis, the coated films exhibit polycrystalline behavior with cubic structure. Structural specifications such as lattice parameters, crystallite size, strain, dislocation density, and crystallinity of the films are investigated. SEM is used to examine the surface characteristics of the prepared films. The optical bandgap of the sprayed films is calculated from transmittance data utilizing the Tauc plot. Structural distinctions of the NiO films are investigated with Raman spectroscopy. Several harmful gases, including ammonia, ethanol, methanol, acetone, xylene and formaldehyde sensing characteristics have been studied. The material coated at 400 °C has revealed better selectivity and sensitivity of 598 towards 25 ppm of formaldehyde at ambient temperature with a quick response of 16.5 s and recovery of 29.8 s.

Shock-induced plasticity and resultant defect analysis in a vacuum kinetic sprayed silver film

High velocity particle impact generates a shock wave that penetrates the material, resulting in severe plasticity and damage. Finite element method simulation demonstrates that Ag particle momentarily undergoes severe deformation with a high strain rate because of stress fluctuation in the material during the shock wave passage. High-resolution transmission electron microscopy analysis reveals that the lattice was severely distorted, flow-like bent with many geometrically necessary dislocations and stacking faults, twinned at the nanoscale, and collapsed into amorphous state.