Increase In Angle Research Articles

Analyzing the spectrum characteristics of a double-grating transmission scheme

In this paper, the spectral characteristics formed by a double-grating transmission scheme are discussed based on the scalar diffraction theory. First, considering two different grating periods, the angular spectrum at the back of the second grating is obtained. Then, the spectral characteristics are discussed with three different periodic conditions, while it is proved that the spatial distribution and spacing of the spectrum are absolutely determined by the grating constants and angles. The theoretical results manifest that the spatial distribution range of the spectrum becomes larger as the angle increases, unlike the spectral points, which are distributed on a single line when the grating lines of the two gratings are parallel. Finally, for the sake of proving that our theoretical analysis is correct and reasonable, three sets of experiments are conducted with three different combinations of Ronchi gratings. As expected, the experimental and theoretical results are in perfect agreement. In a word, the involved results could be useful for expanding the application of moiré deflectometry.

Efficient ibuprofen removal using enzymatic activated ZIF-8-PVDF membranes

This study investigated the development of poly(vinylidene fluoride) (PVDF) hybrid ultrafiltration membranes, where ZIF-8 nanocrystals are synthesized in situ within the membrane pores. These ZIF-8 embedded membranes are specifically designed for the treatment of emerging pollutants, such as ibuprofen. The optimized membrane, characterized by a higher concentration of ZIF-8 and greater surface coverage, exhibited significantly enhanced performance and improved properties, including increased hydrophobicity and mechanical strength. By increasing the zinc concentration from 0.2 to 0.3 M during the preparation of the ZIF-8 coated membrane, hydrophobicity was enhanced, as indicated by an increase in the contact angle from 60.3° to 87.2°, along with improved porosity from 41.3% to 60.5%. Further performance enhancements were achieved by encapsulating enzymes, specifically laccase and peroxidase, within the ZIF-8 coated membrane. A comparison of ibuprofen removal by these enzymes showed that peroxidase was slightly more effective, reaching a maximum removal efficiency of approximately 45% within 2 h. The biocatalytic membranes demonstrated a high stability and reusability, underscoring their potential for efficient ibuprofen removal. These findings highlight the efficacy of ZIF-8-coated PVDF membranes as advanced tools for water purification, offering significant improvements in both purification efficiency and membrane stability.

Serial Optical Coherence Tomography Assessment of Coronary Atherosclerosis and Long-Term Clinical Outcomes.

The impact of high-risk coronary artery plaques identified using optical coherence tomography on late luminal narrowing and clinical events remains poorly understood. This multicenter prospective study included 176 patients who underwent percutaneous coronary intervention and serial optical coherence tomography at baseline and 1-year follow-up to investigate nontarget regions with angiographically intermediate stenosis. At 1 year after percutaneous coronary intervention, the coronary artery lumen area decreased significantly from 6.06 (95% CI, 5.60-6.53) mm2 to 5.88 (95% CI, 5.41-6.35) mm2 (difference, -0.18; 95% CI, -0.22 to -0.14 mm2; P<0.001), particularly in thin-cap fibroatheromas, thick-cap fibroatheromas, mixed plaques, and fibrous plaques. The prevalence of fibroatheroma decreased from 38% to 36% (P<0.001), whereas calcified plaque increased from 31% to 34% (P<0.001), accompanied by a significant increase in calcium thickness and angle. Diabetes and current smoking habits were independently associated with increasing calcium prevalence. Patients with thin-cap fibroatheroma had a significantly higher 3-year risk of ischemia-driven nontarget vessel revascularization (hazard ratio, 2.42 [95% CI, 1.03-5.71]; P=0.04), primarily due to revascularization in the imaged region. No significant association was observed between coronary artery calcium prevalence and clinical outcomes within 3 years. The coronary artery lumen area significantly decreased over a 1-year interval, particularly in thin-cap fibroatheromas, thick-cap fibroatheromas, mixed plaques, and fibrous plaques. Although thin-cap fibroatheroma prevalence was associated with higher risk of ischemia-driven nontarget vessel revascularization, no significant association was noted between coronary artery calcium prevalence and clinical outcomes within 3 years. The interaction between calcium progression and long-term clinical events necessitates further investigation. URL: https://www.umin.ac.jp/ctr/; Unique Identifier: UMIN000031937.

Mixing enhancement with minimal thrust loss for the Mach 1.76 jet issuing from different beveled collar nozzles

The main objective of the present investigation is to enhance the jet mixing by introducing a nozzle collar exit inclination having bevel angles of 30°, 45°, and 60°. In addition to this, the present study also addresses the problem of investigating the jet which attains maximum mixing from beveled collar nozzle with the imposition of a minimal overall thrust loss penalty. The nozzles of the present study have been designed to deliver a uniform Mach 1.76 jet at the nozzle collar exit. The results thus obtained through numerical computations have been compared with that of the reference nozzle which has zero exit inclination. The investigations have been performed under both design and off-design conditions of the jet by varying the nozzle pressure ratio (NPR) from 4.5 to 6.5 with unit step size. It is seen that the rate of jet mixing is augmented with the increase in the bevel angle. Thus, the 60° beveled collar nozzle demonstrated the highest jet mixing in comparison to the reference nozzle, 30° and 45° beveled collar nozzle at each nozzle pressure ratio. However, 60° beveled collar nozzle has been substantially penalized with the highest thrust loss of about 6.5% at nozzle pressure ratio 4.5 and about 3.5% at nozzle pressure ratio 5.5 with respect to the reference nozzle and other nozzles of the present study. The 45° and 30° beveled collar nozzles reported the thrust penalty below 2.3% and 1%, respectively. The overall performance, which includes mixing enhancement along with the minimal thrust loss, has been found in the 45° beveled collar nozzle, which clearly justifies its preference over the other investigated nozzle configurations.

One-Step Magneton Sputtering of Crystalline Cu-Doped TiO2 Coatings: Characterization and Antibacterial Activity

Early biofilm formation could be inhibited by applying a thin biocompatible copper coating to reduce periprosthetic infections. In this study, we deposited crystalline Cu-doped TiO2 films using one-step DC magnetron sputtering in an oxygen atmosphere on a biased Ti6Al4V alloy without external heating. The bias voltage varied from −25 V to −100 V, and the resultant substrate temperature was measured. The deposited coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness, scratch and hydrophilicity tests, potentiodynamic polarization measurements, and antibacterial assays against S. aureus and E. coli. The findings demonstrated that when a higher negative bias is applied, the substrate temperature drops, and the anatase to rutile transformation is initiated without indicating obvious Cu-containing phases. The SEM images of the films showed spherical agglomerates with homogeneously distributed Cu with decreasing Cu content as the bias value increased. Higher bias results in the grain refinement of the thinning coatings with more lattice microstrain and more defects, together with an increase in water contact angles and hardness values. Samples biased at −75 V exhibited the highest adhesive strength between coatings and substrate, whereas the specimen biased at −50 V demonstrated higher corrosion resistance. Cu-containing TiO2 coatings with pure anatase phase composition and Cu concentrations of 2.62 wt.% demonstrated excellent bactericidal activity against both S. aureus and E. coli. The layers containing 2.34 wt.% Cu exhibited very good antibacterial properties against S. aureus, only. According to these findings, the produced copper-doped TiO2 coatings have high bactericidal qualities in vitro and may be used to prepare orthopaedic and dental implants in the future.

Particle flow simulation of crack propagation and penetration in Brazilian disc under uniaxial compression

The presence of rock mass fractures has always been a subject of study for the prevention and control of related natural disasters. To understand the effects of different dip angles and horizontal distances on crack development, numerical simulation experiments on Brazilian disks under uniaxial compression were con-ducted using the PFC2D particle flow program. A function module was utilized to monitor the expansion and quantity of cracks. The numerical simulation results under 0&amp;deg; conditions were in good agreement with the experimental results, validating the rationality of the numerical simulation. The simulation results indicate that: under single fracture conditions with different dip angles, samples with angles between 30&amp;deg; and 60&amp;deg; produced typical wing-shaped cracks. At 0&amp;deg;, cracks propagat-ed through the center of the fracture, while at 90&amp;deg;, cracks initiated from the tip of the fracture and propagated through the sample. The peak stress and the number of cracks in the samples first decreased and then increased with the increase of the dip angle, reaching a maximum at 90&amp;deg;. For samples with double fractures and varying horizontal distances, all produced wing-shaped cracks. Their peak stress and the number of cracks increased monotonically with the increase in distance, reaching a maximum at a distance of 30mm. The experimental results confirmed that the PFC2D program can effectively simulate the process of crack initiation and development, and the research findings provide a reference for correctly understanding the fracture mechanics of fractured rock masses.

Investigating the influence of geometric configurations and loading modes on mixed mode I/II fracture characteristics of rocks: Part I-Numerical simulation

The influence of geometric configurations and loading modes is a bottleneck that restricts the accurate determination of rock fracture parameters and the precise understanding of fracture mechanisms. Therefore, the phase field method is employed to analyze the influences of specimen geometry and loading modes on the dimensionless stress intensity factors, peak load, fracture toughness, and crack initiation angle during the rock mixed mode I/II fracture process. Three new configurations of specimens are proposed to test rock mixed mode I/II fracture. The research results indicate that as the prefabricated crack inclination angle increases, the peak load of three-point bending type specimen increases, while the peak load of diametric-compression type specimen decreases. Moreover, the influence of geometric configurations on the fracture parameters of three-point bending specimens is greater than that of diametric-compression disk specimens. The research findings of this work can provide basic supporting data for the establishment of mixed mode I/II fracture testing standards.

The mechanical and hydrochemical properties of cemented calcareous soil under long-term soaking

This study investigates the impact of long-term water immersion on the mechanical and hydrochemical properties of cemented calcareous soil, emphasizing the critical role of carbonate content in mechanical performance. Utilizing hydrochemical analysis and triaxial testing, the research revealed that prolonged immersion disrupts the acid-base balance of the solution, resulting in an increased concentration of ions and chemicals. Significant dissolution of carbonates and soluble minerals occurs, which reacts with carbon dioxide to generate bicarbonate ions, thereby elevating the alkalinity of the soaking solution. Additionally, the gradual dissolution of clay minerals compromises the cementitious structure, leading to particle reorientation and interlocking. The study quantitatively assesses the changes in soil properties, demonstrating a substantial reduction in soil cohesion by up to 86.1% and an increase in the internal friction angle by 37.5%. Furthermore, the gradual dissolution of clay minerals compromises the cementitious structure, resulting in particle reorientation and interlocking that contribute to the observed mechanical changes. The findings underscore the importance of understanding the effects of extended immersion on the stability and engineering applicability of cemented calcareous soils.

Dynamic characteristics analysis of shock absorber based on fluid simulation

Pneumatic spring dampers are extensively utilized within hydraulic systems, and the flow characteristics of the internal oil play a crucial role in determining noise and vibration levels. To validate the mechanical structure's reliability, the shock absorber was simplified and the fluid domain was extracted using a CFD method. The velocity field and pressure field under different conditions were then simulated and analyzed. A finite element model of the flow field was established, and its accuracy was verified by comparing simulation results of gas side pressure with experimental results. According to the working principle of the oil-gas spring, dynamic active surfaces in contact with the main piston and dynamic driven surfaces in contact with the floating piston were defined, determining moving conditions for dynamic grids. The results indicate that as the diameter of flow channels increases, there is a decrease in average pressure drop within the oil chamber (i.e., pressure loss within the flow field). Additionally, as bend angle increases, average pressure drop decreases. However, optimization effects become less significant beyond a certain bend angle.

Experimental investigation on wind loads and wind-induced responses of large-span flexible photovoltaic support structure

Flexible photovoltaic (PV) support structure offers benefits such as low construction costs, large span length, high clearance, and high adaptability to complex terrains. However, due to the high flexibility and low damping of the cable system, wind load becomes the primary control factor for structural safety and the key consideration in the design. In this study, a 45 m span flexible PV support structure with 3 spans and 12 rows was designed. The wind loads on PV panels were obtained by wind tunnel tests on a rigid model and the wind-induced responses were investigated by wind tunnel tests on an aeroelastic model. The shielding effects and tilt angle of PV modules on the wind load and wind-induced vibration of the flexible PV support were studied. The experimental results show that in the rigid model wind tunnel test, the wind pressure on the surface of PV modules exhibits a gradient distribution along the direction of wind flow, with symmetric distribution along the mid span. With the increase in the tilt angle of the PV module, the shielding effect becomes significant and the most pronounced shielding effect on the mean wind pressure coefficient occurs in the second row of the windward zone. In aeroelastic model wind tunnel tests, the mean vertical displacement of the flexible PV support structure increases with the increase of wind speed and tilt angle of PV modules. Due to the wind-resistant anchor cables set in both the windward and leeward zones, the vibration amplitude near the edge rows is significantly smaller than that of the middle rows when the structure is subjected to wind suction. When the flexible PV support structure is subjected to wind pressure, the maximum mean vertical displacement occurs in the first rows at high wind speeds. The shielding effect has a noticeable impact on the wind-induced response of the leeward zone at α = 20° under wind pressure, resulting in the decrease of amplitude vibration by approximately 53 %. The wind vibration coefficients in different zones under the wind pressure or wind suction are mostly between 2.0 and 2.15. Compared with the experimental results, the current Chinese national standards are relatively conservative in the equivalent static wind loads of flexible PV support structure.

Study on the wetting characteristics of liquid-Al/ SiO2 interface with Si content in liquid-Al

Aiming to address the issue of aluminum slag adhering to the interior walls of vacuum lifting ladles in the aluminum electrolysis industry, Molecular dynamics simulations are employed to investigate the wetting behavior and adhesion characteristics of aluminum droplets on silica surfaces. Our findings indicate that with an increase in silicon content within the droplets, wetting diminishes and complete wetting of the silica substrate by aluminum droplets is not achieved. The presence of silicon reduces both the melting point temperature and surface tension of aluminum droplets, leading to a significant increase in contact angle and a corresponding decrease in wettability. Moreover, an elevated silicon content within molten aluminum droplets substantially decreases their interaction energy with the substrate surface. The virtual wall method is applied to examine average separation force and work of separation for detaching aluminum droplets from the substrate, revealing that adhesion characteristics are predominantly governed by mutual adhesive forces. This paper presents an atomic-level analysis elucidating how silicon as an alloying element influences adhesion between liquid aluminum and solid surfaces.

Synthesis of Polyether Block Copolymers from 1,2-Epoxybutane and AEOn and Comparative Study of Physicochemical and Application Properties before and after the Synthesis.

In this study, the AEOnBO2 series of block polyoxybutenol ethers was synthesized by combining the AEO series of polyoxyethylene and preparing 1,2-epoxybutane (BO) block polyether using a semicontinuous method. The synthesis was performed by HPLC, MALDI-TOF-MS, FT-IR, and 1H NMR for structural analysis. The interaction parameters and surface tension of the systems before and after synthesis were studied using surface tension meter. The diffusion process of the systems before and after synthesis was studied using a KRÜSS bubble pressure tensiometer. The surfactant properties of AEOn and AEOnBO2 were evaluated by static and dynamic surface tension measurements. Each system formed a saturated adsorption layer in a water solution. The critical micelle concentration decreased dramatically after the introduction of BO groups, and the diffusion-adsorption process was consistent with the kinetic mechanism of hybrid diffusion. The microscopic self-assembled aggregate micellar behavior of all the systems was investigated using DLS, TEM, and SEM. The micellization process in all systems was spontaneous and enthalpy-driven, forming spherical aggregates, with the BO block reducing the aggregate diameter of the feedstock from 220.06 nm to about one-third of 80.02 nm. In addition, the dynamic contact angle, application, and physicochemical properties such as foaming and foam stabilization of each system were investigated. The contact angle was reduced from 70 to 50° at 120 s of stabilization, with a foam volume of 80 mL in all systems at 200 s. However, the AEOnBO2 showed accelerated foam decay at 500 s, with an increase in the contact angle from 70 to 50° at 200 s, but the AEOnBO2 showed accelerated foam decay at 500 s, with a decrease in the contact angle from 70 to 50° at 120 s stabilization. At 200 s, the foam volume of all systems was 80 mL, but AEOnBO2 showed an accelerated foam decay process, which shows that the BO group can accelerate the foam decay, and the comparative results show that the BO group can also optimize other application properties and physicochemical properties.

Energy-saving mechanism and dynamic characteristics of blade angle adjustment in low head pumping system

To investigate the energy-saving mechanisms and dynamic characteristics of blade angle adjustment, this study proposes a novel research method via simulations, prototype and model testing. For stable conditions, the internal field, the external and energy characteristics of the pumping system with different blade angle are examined. The dynamic characteristics of the pumping system and the blade force characteristics during the adjustment process are also studied. The research results show that, under a certain net head, an appropriate impeller blade angle improves the flow state in the pump and conduits, decreasing the entropy production and providing suitable inlet circulation to reduce the hydraulic loss of outlet conduit, thereby improving the pumping system efficiency by 5–10 percentage points. During the adjustment process, there is an approximate 20-s delay in dynamic characteristics. Additionally, with the increase of the blade angle, the hydraulic torques for blade axis and pump shaft increase, thus increasing the blade adjustment force and shaft power. The adjusting force is found to be underestimated in the adjustment processes of decreasing the blade angle. Achievements of this paper contribute to high efficiency of pumping system and high reliability of blade adjustment devices and pump units.

Study on Crashworthiness of Shrink Tube Anti-Creep Device

Based on the requirements of the narrow installation space of a train end, compact energy-absorbing travel, and huge energy suck, a shrink tube anti-creep device was designed. The crashworthiness of different structures was studied by means of a material test, a trolley test, and numerical simulation. For every 1 mm increase in tube wall thickness, 1 mm increase in the axial length of the friction cone, and 0.01 increase in the friction coefficient, the mean crushing force (MCF) increased by 45.1 kN, 13.5 kN, and 30.5 kN, respectively. When the cone angle of the shrink tube increased from α = 5° to α = 25°, the increase in the MCF with different thicknesses was about 600%. The MCF was most affected by the cone angle, followed by the wall thickness, the friction coefficient, and the axial length of the friction cone. The change in the contact length of the friction cone of the shrink tube under different structural parameters was compared. The contact length decreased with the increase in tube wall thickness and increased with the increase in angle. The variation rule of MCF was obtained to provide a reference for the development of genealogical products.

A Review of the Building Heating System Integrated with the Heat Pipe

The heat pipe (HP) is widely applied in the thermal management field at present. In order to make use of the low-grade and renewable energies to maintain building thermal comfort in the heating season, more and more studies with respect to improving the thermal performance of the building heating system integrated with the HP (BHSIHP), such as the floor heating system integrated with the HP (FHSIHP), the thermal storage wall heating system integrated with the HP (TSWIHP), conventional wall integrated with the HP (WIHP) and radiator heating system integrated with the HP (RHSIHP), are conducted. This paper aims to summarize different types of HPs applied in the building heating system and offers an overview of the thermal performance improvement for the BHSIHP. The thermal response, thermal conductivity, thermal resistance, heat capacity, heat transfer coefficient, temperature distribution, thermal storage and heat release capacity are always selected to investigate characteristics of the BHSIHP. Results show that the thermal performance of the FHSIHP, the TSWIHP, the WIHP and the RHSIHP is more outstanding than that of the conventional heating system. The thermal performance of the BHSIHP is affected by heat source temperature, installation tilt angle, working fluid, and filling ratio of the HP. The heat source temperature, which positively affects the performance of the BHSIHP, is crucial for the selection of the working fluid and filling ratio. However, the performance of the BHSIHP is increased first and then decreased with the increase of the installation tilt angle. The optimal filling ratio of the working fluid has been proven not to be a fixed value.

Mechanical properties of diamane: Orientation dependence of strength and fracture strain

Diamane, the two-dimensional counterpart of diamond, is very promising for novel electronic and nanomechanical devices, which requires additional studies on their physical and mechanical properties. In the present work, the orientation dependence of diamane strength with the detailed analysis of the deformation behavior was carried out by molecular dynamics. Two stacks of diamane layers covered with hydrogen with different chirality θ from 0 to 30° were considered. The atomic stacking of diamane has no effect on its strength. It was found that diamane strength depends non-monotonously on the diamane chirality: the highest strength was found for θ = 10°. The fracture strain decreases with the increase of chiral angle from 0 to 20° and does not change for chirality from 20 to 30°. However, the Young’s modulus does not depend on the diamane chirality. The main deformation mechanisms were revealed: elongation of covalent bonds and rotation of valence angles. For chiral angles from 0 to 20°, the diamane chirality can be controllably changed during tension which results in the increase in fracture strength and strain. The obtained results allow a better understanding of the effect of the diamane morphology on their mechanical properties for future applications.

Research on Gas Explosion Pressure and Flame Propagation Characteristics in Turning Pipelines.

In order to investigate the overpressure and flame propagation characteristics of gas explosions in turning pipelines, this study designed a transparent organic glass pipeline test system with different turning angles (30°, 60°, 90°, 120°, and 150°) and conducted a series of experimental studies to analyze the explosion shock wave overpressure and flame propagation behavior. The experimental results show that with the increase of the turning angle of the pipeline, the overpressure of the explosion shock wave significantly increases. In terms of flame propagation characteristics, when the turning angle is small, the flame can adhere to the outer wall of the pipeline corner and gradually fill the entire pipeline section. When the turning angle increases, the flame forms a blank area near the outer wall of the corner, and the blank area expands with the increase in the corner. In addition, the increase in the turning angle promotes the increase in the velocity of the explosion flame front. The research results of this review are of great significance for a deeper understanding of the mechanism of gas explosions in turning pipelines and evaluating their potential hazards.

Decoding Quantum Gravity Information with Black Hole Accretion Disk

Integrating loop quantum gravity with classical gravitational collapse models offers an effective solution to the black hole singularity problem and predicts the formation of a white hole in the later stages of collapse. Furthermore, the quantum extension of Kruskal spacetime indicates that white holes may convey information about earlier companion black holes. Photons emitted from the accretion disks of these companion black holes enter the black hole, traverse the highly quantum region, and then re-emerge from white holes in our universe. This process enables us to observe images of the companion black holes’ accretion disks, providing insights into quantum gravity. In our study, we successfully obtained these accretion disk images. Our results indicate that these accretion disk images are confined within a circle with a radius equal to the critical impact parameter, while traditional accretion disk images are typically located outside this circle. As the observational angle increases, the accretion disk images transition from a ring shape to a shell-like shape. Furthermore, the positional and width characteristics of these accretion disk images are opposite to those of traditional accretion disk images. These findings provide valuable references for astronomical observations aimed at validating the investigated quantum gravity model.

Numerical Simulation of Gas–Water Two-Phase Flow Patterns in Fracture: Implication for Enhancing Natural Gas Production

The main objective of this paper is to investigate the evolution of rock fracture slug structures and decongestion strategies for natural gas extraction processes. For this purpose, the level set method was used to simulate the evolution of the slug structure under the effect of different flow ratios, fracture surface wettability, and fracture tortuosity. The results show that an increase in the water-to-gas flow ratio and fracture tortuosity leads to a significant increase in the proportion of slug structures in the fracture, while an increase in the surface contact angle leads to a decrease in the proportion of slug structures in the fracture. Based on the above slug structure evolution law, a quantitative characterization method for the slug structure of two-phase fluids considering the combined effects of the water–gas flow ratio, average wall contact angle, and flow channel tortuosity was developed. Subsequently, we engage in further discussion on the optimization of the extraction and decongestion process in natural gas extraction.

Optimization Study on Nozzle Selection Based on the Influence of Nozzle Parameters on Jet Flow Field Structure

Currently, the primary method for controlling red tides in the ocean involves spraying water solutions with special chemicals as solutes. High-pressure spraying results in the formation of typical jet structures. In this study, numerical simulation methods are employed to investigate the velocity variations, turbulent characteristics, and gas content distribution of jet flow fields under different initial jet flow pressures, cone angles, and nozzle diameters. Based on practical application scenarios, cluster analysis is used to explore the similarities and differences in jet equivalent diameters under different parameter conditions. The research findings indicate the following. (1) The difference of jet velocity distribution at the far field exit will be enlarged with the increase in the nozzle cone angle. When the nozzle cone angle is 4 mm, the velocity uniformity at the outlet is the best. (2) The TKE of the flow field has no consistent change law along the central axis. At the jet exit, the TKE shows an obvious multi-peak structure. (3) The gas content demonstrates a typical “double-valley” feature at the jet outlet cross-section. Increasing the initial pressure leads to a decrease in the gas content within the jet due to reduced entrainment, while the entrainment range remains largely constant. (4) Cluster analysis reveals that the similarity of jet flow width when it reaches the water surface is minimal compared to other operating conditions when the initial pressure is 0.36 MPa, the cone angle is 115°, and the nozzle diameter is 2 mm. All conditions can be categorized into two or three groups to ensure jet effectiveness. The study results provide scientific guidance for selecting spray devices for controlling red tides in the ocean.