Search Results (169)

In the manufacturing process of advanced integrated circuits, electron beam inspection equipment is crucial for yield assurance, while vibration poses a core challenge affecting its precision and speed. Vibrations in production line equipment are mostly multi-frequency; However, research findings in this field remain limited. Moreover, existing compensation schemes often struggle to meet industrial-grade precision and real-time requirements. This paper presents the design and implementation of a high-speed electron beam vibration compensation system based on positioning. The system incorporates state-of-the-art laser positioning and electrostatic scanning deflectors, and features an integrated signal processing and compensation signal output module. The study involved improvements and optimizations to the positioning processing analysis and compensation module, control software and algorithms, and calibration software and algorithms, demonstrating superior performance compared to existing methods. System validation data demonstrates that the proposed scheme effectively compensates for both single-frequency and multi-frequency disturbances at frequencies below 200 Hz, achieving an average attenuation of 50% to 90% and a repetitive compensation accuracy of less than 0.3 nm. These metrics meet the industrial application requirements for electron beam inspection equipment. The overall error in long-term repeatability tests complies with the stability demands of industrial production lines, confirming its practical applicability in production environments. Full article

Non-thermal plasma is a promising technology for odor abatement from agricultural and domestic waste. However, its widespread application is often limited by the inherent trade-off between energy efficiency and processing capacity in conventional reactors. To address this challenge, we propose a novel multi-needle-to-cylinder dielectric barrier discharge reactor integrated with a deflector ring. By synergistically optimizing the electrode topology and modulating the flow field, this reactor achieves enhanced removal of complex ammonia–sulfur odor mixtures. The underlying mechanisms were elucidated through computational fluid dynamics (CFD) simulations coupled with systematic performance evaluation. Experimental results demonstrate that an 8-needle electrode configuration provides the optimal balance between discharge density and energy efficiency. CFD simulations further reveal that the deflector ring effectively suppresses gas bypass and promotes recirculation vortices downstream, thereby extending the residence time significantly. Mechanistic studies indicate that the removal of recalcitrant inorganic sulfides (e.g., CS₂ and H₂S) follows a synergistic mass-transfer–reaction controlled process, which is markedly improved by flow field optimization. In contrast, organic sulfides are governed primarily by chemical kinetics and show little dependence on flow variations. Under an extremely short residence time of 0.57 s (corresponding to a flow rate of 2.0 m³/h) and an ultra-low specific energy input of 6.26 J/L, the system achieved nearly complete removal of organic sulfides. Even for challenging inorganic sulfides, removal efficiencies reached 80.9% for H₂S and 45.3% for CS₂, while O₃/NO_x/SO₂ byproducts were quantified. For industrial deployment, these byproducts can be managed by standard downstream polishing. By effectively coordinating discharge characteristics with flow dynamics, this study provides both theoretical insight and technical support for the development of next-generation, energy-efficient, high-throughput industrial odor control systems. Full article

Aiming at the wind-blown snow disasters plaguing tunnel portals along the China-Tajikistan Highway Phase II Project, this study optimizes the protective parameters of wind deflectors through numerical simulation to improve the disaster prevention efficiency of tunnel portals in alpine mountainous areas. Three core control parameters of wind deflectors, namely horizontal distance from the tunnel portal (L), plate inclination angle (β), and top installation height (h), were selected as the research objects. Single-factor numerical simulation scenarios were designed for each parameter, and an L9(3³) orthogonal test was further adopted to formulate 9 groups of multi-parameter combination scenarios, with the snow phase volume fraction at 35 m on the leeward side of the tunnel portal set as the core evaluation index. A computational fluid dynamics (CFD) model was established to systematically investigate the influence laws of each parameter on the wind field structure and snow drift deposition characteristics at tunnel portals and clarify the flow field response rules under different parameter configurations. Single-factor simulation results show that the wind deflector exerts distinct regulatory effects on the wind-snow flow field with different parameter settings: when L = 6 m, the disturbance zone of the wind deflector precisely covers the main wind flow development area in front of the tunnel portal, which effectively lifts the main incoming flow path, compresses the recirculation zone (length reduced from 45.8 m to 22.3 m), and reduces the settlement of snow particles, achieving the optimal comprehensive prevention effect; when β = 60°, the leeward wind speed at the tunnel portal is significantly increased to 10–12 m/s (from below 10 m/s), which effectively promotes the transport of snow particles and mitigates the accumulation risk, being the optimal inclination angle; when h = 2 m, the wind speed on both the windward and leeward sides of the tunnel portal is significantly improved, and the snow accumulation risk at the portal reaches the minimum. Orthogonal test results further quantify the influence degree of each parameter on the snow prevention effect, revealing that the horizontal distance from the tunnel portal is the most significant influencing factor. The optimal parameter combination of the wind deflector is determined as L = 6 m, β = 60°, and h = 2 m. Under this optimal combination, the snow phase volume fraction at 35 m on the leeward side of the tunnel portal is 0.0505, a 12.3% reduction compared with the non-deflector condition; the high-concentration snow accumulation zone is shifted 25 m leeward, and the high-value snow phase volume fraction area (>0.06) disappears completely, which can effectively alleviate the adverse impact of wind-blown snow disasters on the normal operation of tunnel portals. The research results reveal the regulation mechanism of wind deflector parameters on the wind-snow flow field at alpine tunnel portals and determine the optimal protective parameter combination, which can provide important theoretical reference and technical support for the prevention and control of wind-blown snow disasters at tunnel portals in similar alpine mountainous areas. Full article

It has long been known that inlet port geometry plays a crucial role in regulating in-cylinder flow processes, significantly affecting combustion efficiency and engine emissions. This paper elucidates the effects of an intake port geometry modification, specifically the implementation of a novel moving deflector to intensify tangential intake flow, on fluid flow patterns, combustion stage, and exhaust emissions in a spark-ignited internal combustion engine. The analysis was performed using multi-dimensional numerical modeling of reactive flow, where the numerical domain was extended to the complete intake system to explicitly encompass the modification. The numerical model was validated against experimental data, showing excellent agreement, with differences in peak in-cylinder pressure and peak rate of heat release (RHR) kept below 3% and the moment of peak pressure being nearly identical to the experimental results. During the induction stroke, the effects of implemented modification through intensification of intake jet were clearly legible, pursued by deflection of smaller side vortices in the vicinity of the bottom dead-center. During compression, the attenuation of the effects of the earlier established macro flow was encountered and some negative effects of the increased intake jet were elucidated. During combustion the existence of “flame dominated fluid flow” controlled primarily by turbulence diffusion was encountered. Negative effects on exhaust emissions were elucidated as well. As the combustion process in spark ignition internal combustion engines is primarily controlled by turbulent diffusion, proper identification of influential types of organized flows is a challenging but very important task. The advantages offered by the application of numerical modeling in these situations are clear. Full article

This study employs CFD simulations carried on ANSYS Fluent 2022 R1 (ANSYS Inc., Canonsburg, PA, USA), to address the design, development, and thermodynamic analysis of a biomass burner, based on mass and energy balances, combustion efficiency, flame temperature, and thermodynamic properties. The prototype incorporates a flow deflector located before the combustion chamber. This component improves the air-fuel mixture to maximise thermal efficiency and minimise pollutant emissions. The burner is specifically designed to use sawdust as fuel and is intended for industrial applications such as heating or drying processes. The integration of the flow deflector results in uniform, complete combustion, achieving 90% thermal efficiency and an adjustable thermal power output of 0–100 kW. Compared to conventional burners, this design reduces CO emissions by 20% and NO_x emissions by 15%, demonstrating significant environmental improvements. The design methodology is based on mass and energy balance equations to evaluate combustion efficiency as a function of the stoichiometric ratio, along with experimental testing. These experimental tests were conducted using an ECOM (America Ltd., Nashua, NH, USA) gas analyser and anemometer. The internal temperature was monitored with a K-type thermocouple (Omega Engineering Inc., Norwalk, CT, USA). The results confirmed the positive influence of the structural design on thermal performance. The proposed burner aims to maximise heat generation in the combustion chamber, offering an innovative alternative for biomass combustion systems. Full article

This study presents a compact, 3D-printed Savonius wind turbine rotor incorporating pointed deflectors to enhance concave-side airflow and mitigate blade-edge vortex formation. The prototype, fabricated from ABS plastic, was experimentally evaluated in an Eiffel-type wind tunnel under low-speed wind conditions (3, 4, and 5 m/s), with blockage effects taken into account. Flow visualization revealed improved airflow attachment and pressure concentration on the concave blade surfaces, increasing drag asymmetry and torque generation. Corresponding power coefficients with applied blockage ratio were observed to be 0.181, 0.185 and 0.186, while torque coefficients with applied blockage ratio were observed to be 0.385, 0.374 and 0.375 at each wind speed and optimal tip-speed ratio, respectively, and were compared with previously reported computational results. The optimal operating tip-speed ratios identified for the torque and power coefficients were remarkably close, enabling efficient torque and power generation during operation. The experimental findings validate earlier numerical predictions and underscore the importance of physical testing in assessing turbine performance. Observed deviations between predicted and experimental coefficients suggest that fabrication parameters may influence prototype performance and warrant further investigation. Overall, the results demonstrate the technical viability of 3D-printed Savonius turbines for small-scale urban energy harvesting applications in the Philippines. Full article

Curtain deflector coating is a widely employed technique for producing thin, uniform films in numerous industrial applications. The flow dynamics in curtain coating become complex near the corner region due to the interaction of the moving substrate and the falling liquid curtain. In this study, an analytical investigation is conducted for the steady, in-compressible, and creeping flow of a Maxwell fluid, under the Navier slip condition at the substrate. The mathematical model is derived from the conservation of mass and momentum representing the nonlinear system which is solved using the Langlois recursive technique in combination with the inverse method. The inclusion of the Navier slip boundary condition in this research makes it novel and remove the singularity which produce the unstable stresses at a sharp corner due to no slip, but the Navier slip gives a stable solution for the stresses at a sharp corner. The analysis demonstrates that substrate slip significantly reduces tangential stresses and enhances the stability of the coating flow. Residual error analysis is also performed to verify the accuracy and convergence of the analytical solutions. The results provide a deeper understanding of how slip effects can be utilized to improve coating uniformity and optimize the operational performance of curtain deflector coating systems. Full article

We report on the realization of a platform for trapping and manipulating individual ⁸⁸Sr atoms in optical tweezers. A first cooling stage based on a blue shielded magneto-optical trap (MOT) operating on the ${|}^1{\mathrm{S}}_0⟩\to {|}^1{\mathrm{P}}_1⟩$ transition at $461 \mathrm{n}\mathrm{m}$ enables us to trap approximately 4 × 10⁶ atoms at a temperature of 6.8 mK. Further cooling is achieved in a narrow-line red MOT using the ${|}^1{\mathrm{S}}_0⟩\to {|}^3{\mathrm{P}}_1⟩$ intercombination transition at 689 nm, bringing 5 × 10⁵ atoms down to $5\mu \mathrm{K}$ and reaching a density of 4 × 10¹⁰ cm³. Atoms are then loaded into 813 nm tweezer arrays generated by crossed acousto-optic deflectors and tightly focused onto the atoms with a high-numerical-aperture objective. Through light-assisted collision processes we achieve the collisional blockade, which leads to single-atom occupancy with a probability of about 50%. The trapped atoms are detected via fluorescence imaging with a fidelity of $99.986\left(6\right)\%$, while maintaining a survival probability of $97\left(2\right)\%$. The release-and-recapture measurement provides a temperature of $12.92\left(5\right)\mu \mathrm{K}$ for the atoms in the tweezers, and the ultra-high-vacuum environment ensures a vacuum lifetime higher than 7 min. These results demonstrate a robust alkaline-earth tweezer platform that combines efficient loading, cooling, and high-fidelity detection, providing the essential building blocks for scalable quantum simulation and quantum information processing with Sr atoms. Full article

Polyethylene (PE) films are widely used as waterproofing materials on the surfaces of metal pipelines. Poor adhesion of PE films to a metal substrate reduces durability, leading to shorter service life and higher economic costs. The current research aims to study the modification of PE films in atmospheric pressure gliding arc plasma (GAP). The adhesion properties of the modified films were investigated using the contact angle method and adhesion work calculations. During the modification process, the GAP treatment duration and deflector nozzle angle of attack were optimized to 10 s and 135°, respectively. It was established that the adhesion work increased from 62.1 to 141.3 mJ/m² after 10 s GAP modification compared to untreated PE. GAP modifying of PE films for 30 s or more is impractical, as the increase in the adhesion work ceases after that. It was found that surface roughness R_max increased by up to 4.1 times after 10 s GAP modification compared with nontreated PE. The PE films acquired hydrophilic properties after plasma modification, due to changes in the polymer surface’s chemical structure. The results of IR spectroscopy studies indicated oxidation of the film surface, an increase in the concentration of surface polar groups (-COOH, OH, C=O), and the formation of double bonds (C=C), which led to improved adhesive properties. A study of the electret properties showed that the observed decline and subsequent stabilization of values occurred within the first 24 h. Mechanical tests indicated improved performance of the GAP-modified PE films compared to the non-treated ones in the PE–mastic–PE and PE–mastic–steel systems. Due to their enhanced contact properties, the modified PE films are of interest as a base material for creating waterproofing materials. Full article

In order to minimize problems associated with the operation of surface water intakes, passive wedge-wire screens are increasingly being used. Deflectors of special design are placed inside the intake heads to reduce local maximum inlet velocities and to ensure a uniform velocity distribution over their surface. The use of computer software based on Computational Fluid Dynamics (CFD) methods enabled simulations and optimization of the intake head design. Subsequently, a series of laboratory tests was conducted. Several scenarios were considered, varying the flow rates in the hydraulic flume and taking into account both the presence and absence of the deflector. Velocities around the intake head were measured, and the amount of particles in the water attracted to the head surface under the analyzed conditions was assessed. The results confirm the clear effect of the deflector on the velocity distribution. Its use originates reduced velocities near the head surface, as well as a smaller amount of debris deposited on the screen, while maintaining efficiency. At the same time, lower inlet velocities close to the head surface reduce the risk of entrainment and potential injury or mortality of young fish, fry, and eggs. Full article

Air flotation separation technology has emerged as one of the core techniques for oily wastewater treatment in oilfields, owing to its advantages of high throughput, high separation efficiency, and short retention time. Originally applied in mineral processing, this technology was first introduced to oilfield produced water treatment by Shell in 1960. With the optimization of microbubble generators, advances in microbubble generation technology—characterized by small size, high stability, and uniformity—have further expanded its applications across various wastewater treatment scenarios. To optimize the separation performance of a horizontal compact closed-loop cyclonic air flotation unit, this study employs CFD numerical simulation to investigate two key aspects: First, for the flotation zone, the effects of structural parameters (deflector height, inclination angle) and operational parameters (gas–oil ratio, bubble size, inlet velocity) on flow patterns and gas distribution were systematically examined. Device performance was evaluated using metrics such as gas–oil ratio distribution curves and flow field characteristics, enabling the identification of operating conditions for stratified flow formation and the determination of optimal deflector structural parameters. Second, based on the Eulerian multiphase flow model and RSM turbulence model, a numerical simulation model for the oil–gas–water three-phase flow field was established. The influences of key parameters (bubble size, throughput, gas–oil ratio) on oil–water separation efficiency were investigated, and the optimal operating conditions for the unit were determined by integrating oil-phase/gas-phase distribution characteristics with oil removal rate data. This research provides theoretical support for the structural optimization and engineering application of horizontal compact closed-loop cyclonic flotation units. Full article

Perforated cylindrical shaped metal plates are used with high efficiency in the manufacture of deflectors, components of cooling systems, wind tunnels, climatic chambers, filters, and cylindrical implants. This is particularly important for lightweight cylindrical structures, where even minor changes in stiffness can affect structural strength. One of the most important parameters determining the mechanical behavior of such structures is the effective elastic modulus of the perforated element which characterizes its resistance to deformation. The research involves plates made of stainless steel 304 alloy, where perforations were created using the laser-cutting method. The cylindrical shape of the samples with height 50 mm, thickness 1 mm, and diameter 48 mm of each specimen was obtained using metal rolling and welding techniques. To determine the effective elastic modulus, a non-destructive material property evaluation method was applied by solving an inverse problem. In this research, resonance frequencies were determined using a laser vibrometer and a full factorial experimental plan was developed. Physical samples were digitized into 3D models using 3D scanning technology. To evaluate the accuracy of the applied finite element numerical model, its convergence analysis was performed. Numerical results were approximated using the least-squares method, while the effective elastic modulus was calculated by formulating and minimizing the error functional between experimental and numerical eigenfrequencies. The results indicate that increasing the relative perforation area from 0% to 50.24% leads to a decrease in the effective elastic modulus from 184.76 GPa to 50.69 GPa, confirming that increasing the perforation area in a stainless steel 304 cylinder reduces its elastic properties. The observed reduction in resonance frequencies and elastic properties is primarily due to the stiffness decrease caused by the higher perforation volume. Full article

Sustainable mine geothermal energy causes high-temperature hazards in mine roadways, severely endangering miners’ lives. There is an urgent need to enhance research on the performance of composite phase change material (CPCM) roadway cooling systems, as they can effectively control ambient temperatures. However, existing research on CPCM roadway cooling system performance remains limited. This study innovatively establishes a numerical model for a novel cascade CPCM roadway cooling system and employs the control variable method to investigate the influence of multi-parameter regulation on system performance. The study reveals that the ring pipe radius ratio significantly impacts the system’s heat exchange efficiency and temperature distribution. The optimal comprehensive system performance is achieved at an annular tube radius ratio of 2:3, where the CPCM solid phase percentage for 89.03% and the average temperature of the monitoring surface decreases by 9.54 °C. Increasing the cascaded tube spacing enhances the overall cooling effect, but cooling efficiency diminishes when the spacing exceeds 0.5 m. The CPCM phase change temperature must align with the mine’s geothermal conditions, with CPCM utilization and cooling efficiency peaking at 25 °C. The air deflector structure effectively mitigates cooling lag in the lower roadway section. At an installation angle of 30°, the expansion distance of the lower low-temperature zone increased by up to 48.89% without compromising cooling efficiency in the upper roadway section, while also delaying the recovery rate of heat damage. Full article

The paper describes an installation and procedure for evaluating the velocity profile for the airflow produced by the fan of the cleaning unit of a New Holland wheat combine harvester. The velocity profile is based on measurements taken at 52 points spread over the entire surface of the top and bottom sieves, for different speeds of the fan, different positions of the wind boards and different opening positions of the sieves. The experimental data obtained were graphically represented using the Radial Basis Function (RBF) interpolation model and highlighted that the airflow generated by the fan at the upper screen level, in the longitudinal plane and, especially, in the transverse plane, is distributed unevenly, and depends on the fan rotor speed, the opening of the louvers of the two screens and the arrangement of the two deflectors. The correct adjustment of the cleaning unit and correct evaluation of the air velocity profile over the sieves result in the reduction in grain losses from the upper sieve due to grain flotation, reduction in the content of broken grains in the grain tank due to the reduction in the material flow from the tailing auger as well as reduction in the impurities content of the grain tank due to better separation of the material over the surface of the lower sieve. Full article

Horizontal-axis wind turbines are widely used for wind energy harvesting, but they often encounter flow separation near the blade root, leading to power loss and structural fatigue. A varying-parameter flow deflector (FD) is proposed as a passive flow control method. The FD adopts varying parameters along the blade spanwise direction to match the varying local angle of attack. Numerical simulation using the transition SST k-ω turbulence model combined with the response-surface methodology are used to investigate the effect of the varying-parameter FD on the flow structure and aerodynamic performance of the NREL Phase VI wind turbine. The results indicate that optimal performance can be achieved when the normal position of the FD increases from the blade root to the tip, and the install angle of the FD should be greater than 62° at blade section of r/R = 63.1%. Furthermore, response-surface methodology was employed to optimize the deflector parameters, with analysis of variance revealing the relative significance of geometric factors (l₁ > l₂ > θ₁ > θ₂). Compared with the original blade, the shaft torque of the controlled blade with the optimal FD is improved by 24.7% at 10 m/s. Full article