Angle Adjustment Research Articles

Investigating Defect Detection in Advanced Ceramic Additive Manufacturing Using Active Thermography

Additive manufacturing of advanced materials has become widespread, encompassing a range of materials including thermoplastics, metals, and ceramics. For the ceramics, the complete production process typically involves indirect additive manufacturing, where the green ceramic part undergoes debinding and sintering to achieve its final mechanical and thermal properties. To avoid unnecessary energy-intensive steps, it is crucial to assess the internal integrity of the ceramic in its green stage. This study aims to investigate the use of active thermography for defect detection. The approach is to examine detectability using two benchmarks: the first focuses on the detectability threshold, and the second on typical defects encountered in 3D printing. For the first benchmark, reflection and transmission modes are tested with and without a camera angle to minimize reflection. The second benchmark will then be assessed using the most effective configurations identified. All defects larger than 1.2 mm were detectable across the benchmarks. The method can successfully detect defects, with transmission mode being more suitable since it does not require a camera angle adjustment to avoid reflections. However, the method struggles to detect typical 3D-printing defects because the minimum defect size is 0.6 mm, which is the size of the nozzle.

A Low-Cost Modulated Laser-Based Imaging System Using Square Ring Laser Illumination for Depressing Underwater Backscatter

Underwater vision data facilitate a variety of underwater operations, including underwater ecosystem monitoring, topographical mapping, mariculture, and marine resource exploration. Conventional laser-based underwater imaging systems with complex system architecture rely on high-cost laser systems with high power, and software-based methods can not enrich the physical information captured by cameras. In this manuscript, a low-cost modulated laser-based imaging system is proposed with a spot in the shape of a square ring to eliminate the overlap between the illumination light path and the imaging path, which could reduce the negative effect of backscatter on the imaging process and enhance imaging quality. The imaging system is able to achieve underwater imaging at long distance (e.g., 10 m) with turbidity in the range of 2.49 to 7.82 NTUs, and the adjustable divergence angle of the laser tubes enables the flexibility of the proposed system to image on the basis of application requirements, such as the overall view or partial detail information of targets. Compared with a conventional underwater imaging camera (DS-2XC6244F, Hikvision, Hangzhou, China), the developed system could provide better imaging performance regarding visual effects and quantitative evaluation (e.g., UCIQUE and IE). Through integration with the CycleGAN-based method, the imaging results can be further improved, with the UCIQUE increased by 0.4. The proposed low-cost imaging system with a compact system structure and low consumption of energy could be equipped with platforms, such as underwater robots and AUVs, to facilitate real-world underwater applications.

Rotating windmill array beam with adjustable wing angle

Rotating windmill array beam with adjustable wing angle

Controlling windscreen wiper vibration through yaw angle adjustments: a study of dynamic contact behavior using fluorescence observation

Controlling windscreen wiper vibration through yaw angle adjustments: a study of dynamic contact behavior using fluorescence observation

Direct Normal Irradiance Prediction-Based Optimum Interval Tilt Angles for Enhancement of Energy Output, Levelized Cost of Energy, and CO2 Emission in a Grid-Connected Photovoltaic System

Abstract The tilt angle of photovoltaic (PV) panels is a crucial determinant of their performance and can be adjusted using different tracking methods. Periodically changing the tilt angle strikes a practical balance between efficiency and cost. This work introduces a bi-directional long short-term memory (Bi-LSTM)-based direct normal irradiance (DNI) prediction to estimate the time intervals for the tilt angle adjustments. DNI prediction involves 22-year (2000–2022) historical time series data and the Bi-LSTM deep learning model to predict DNI at different time frames for the location Madurai, India. Using the predicted DNI, tilt angle-based DNI is mapped using the tilt angle correlation through a nearest neighborhood interpolation method. DNI potential over a specific period is utilized to find the optimum time intervals for the tilt angle adjustments. The simulation study of this work is implemented with a 5 kW grid-connected solar PV system using pvsyst software. The effectiveness of the proposed methodology is evaluated based on the improvements in power output, levelized cost of energy (LCOE), and carbon emission reductions and compared with other existing methods. The results showed that using the proposed optimal tilt angle intervals led to a 10.31% increase in PV output power, the lowest LCOE at 3.61 c/kW h, and 8.363 tCO2/year carbon emissions.

Iterative Periodic Running Control Through Swept Angle Adjustment With Modified SLIP Model

Iterative Periodic Running Control Through Swept Angle Adjustment With Modified SLIP Model

Revolutionizing superhighway traffic board lighting with remote LED spotlights

In this paper, we present a groundbreaking approach to enhance the illumination of traffic boards along superhighways, addressing significant challenges associated with conventional lighting systems. Our innovative method revolves around the strategic placement of remote spotlights at the side of the roadway to illuminate traffic signs equipped with retroreflector film (RTRF). The essence of our approach lies in remote illumination, which requires meticulous adjustment of the divergence angle of the spotlights to match the size of the signs and their distance from the projection source. To achieve the desired spotlight configuration, we have developed a hybrid optical system that incorporates a paraboloid reflector and a lens mounted on a bridge holder situated on top of the mirror. Through spot light illumination, we discovered that the initial divergence angle of the RTRF was too narrow. To improve projection angle tolerance, we recommend attaching a light diffuser film onto the surface of the RTRF. The coverage area ratio of the diffuser film can be adjusted to select the desired divergence angle for the reflected light. Our experimental measurements have yielded significant results, showcasing the half-divergent angle of the RTRF ranging from 3° to 7° for different coverage area ratios of the diffuser. In practical terms, with a target luminance of 300 nits at the white word on the traffic board, the power consumption of the spotlight fixture of the roadway was only 40 W, representing over 75% power savings when compared to traditional lighting methods. Consequently, our approach opts to utilize spotlights for illuminating specific traffic boards on superhighways, offering a more efficient and manageable lighting solution that greatly benefits both motorists and road maintenance personnel.

Multiple Broadband Infrared Topological Photonic Crystal Valley States Based on Liquid Crystals.

Spectral tunable technology has to meet the requirements of strong robustness and wide spectral range. We propose a method for the transmission and manipulation of infrared topological photonic crystal valley states based on tunable refractive index method that exhibits broad-spectrum and multi-band characteristics, along with a tunable emission angle. With this structure, different rotational directions of vortex light sources can independently excite the K valley and K' valley within the frequency band ranging from 75.64 THz to 99.61 THz. At frequencies from 142.60 THz to 171.12 THz, it is possible to simultaneously excite both the K valley and K' valley. The dual refractive index tunable design allows for the adjustment of the emission angle at a fixed frequency, enabling control over the independent excitation of either a single K valley or K' valley, as well as their simultaneous excitation. This capability has significant implications for photonic computation and tunable filtering, offering enhanced operational flexibility and expanded functionality for future optical communications and integrated optical circuits.

Winding process of fibre-reinforced thermoplastic tubes with integrated tape production through in-situ roving impregnation and infrared consolidation

This paper introduces a novel method for producing fibre-reinforced thermoplastic tubes by integrating tape production and consolidation into a single operation. This innovation diverges from conventional methods by combining processes to reduce costs by using raw materials instead of organotapes, allowing customised material combinations and utilising residual heat from tape production. The new process uses carbon roving and molten low-viscosity PA6 granulates, processed through a new direct impregnation setup in siphon design. Key advancements include a high-speed impregnation module capable of up to 1 m/s with high-performance extruders, cost-effective infrared emitters for winding, and a powered consolidation unit with adjustable winding angles between ± 65° and ± 90°. Experiments demonstrate operational speeds of approximately 471 mm/min, with an optimal cross-winding speed of 354 mm/min due to the technical limitations of the laboratory extruder and IR emitter used. Based on the technical limitations of the current system, future improvements and methodological changes will be discussed.

Self-Repairable Carbon Fiber-Reinforced Epoxy Vitrimer Actuator with Multistimulus Responses and Programmable Morphing.

Smart shape-changing structures in aerospace applications are vulnerable to damage in harsh environments. Balancing high mechanical performance with self-repair capabilities poses a challenge due to inherent trade-offs between strength and flexibility. To address this challenge, an asymmetric bilayer-structured actuator was fabricated using commercially available continuous carbon fiber tows (CFs) as the passive layer and a dynamic cross-linked epoxy vitrimer as the active layer. The construction of the vitrimer-CF actuator involves a simple and scalable hot-pressing process, resulting in a tensile strength of 234 MPa and an interfacial bonding strength of 405 N·m-1. This actuator exhibits remarkable deformation capability (210°/7 s) and an efficient self-repair ability under various stimuli, including thermal (60-160 °C), light (0.4-1.0 W·cm-2), electric (2-4 V), and solvent (acetone). By adjustment of the orientation angle of CFs, complex left-handed and right-handed curling structures can be achieved. Leveraging the insights from photothermal/electrothermal actuation mechanisms, a quadruped crawling robot is developed capable of crawling 4 cm with a single light illumination. The actuator can lift objects 45 times its weight when subjected to light stimuli. Additionally, a flap actuator is constructed to achieve an angle change of 63° within 10 s under an electric stimulus, enabling remote control over the aircraft flight angle. These results demonstrate the potential of the vitrimer-CF actuator for advanced applications in intelligent aerospace structures.

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.

Computational Exploration of Variable-Pitch Fans as Thrust Reversers and Their Influence on Noise Abatement in Turbofan Propulsion Systems

Variable pitch propellers, once confined to turboprop engines, are now revolutionizing turbofan applications. Recent breakthroughs in materials and technology, exemplified by Pratt & Whitney’s geared turbofan engine, underscore the practicality of variable pitch systems. Ongoing research promises to extend their adoption across diverse engine types, significantly enhancing safety and performance. This study investigates a novel approach to enhance reverse thrust using dual-row radial fans with adjustable pitch angles. These fan blades exhibit geometry variations, combining features from both turbofan motor fan blades and turbo- propeller motor blades. The results are promising: this configuration nearly triples the thrust force, producing approximately 292.917 kilo-newtons. Moreover, it enables the generation of reverse thrust equivalent to 25.077 kilo- newtons. These enhancements are achieved while reducing blade rotational speed from 5200 revolutions per minute to 3200 revolutions per minute and inlet airspeed from 660 km/h (at maximum power) to 220 km/h. Additionally, a notable 11% reduction in noise level at the blade tips has been observed. This research sheds light on the potential of innovative fan blade designs to revolutionize reverse thrust capabilities in turbofan engines, contributing to safer and more efficient aircraft landings.

Advanced Cooperative Formation Control in Variable-Sweep Wing UAVs via the MADDPG–VSC Algorithm

UAV technology is advancing rapidly, and variable-sweep wing UAVs are increasingly valuable because they can adapt to different flight conditions. However, conventional control methods often struggle with managing continuous action spaces and responding to dynamic environments, making them inadequate for complex multi-UAV cooperative formation control tasks. To address these challenges, this study presents an innovative framework that integrates dynamic modeling with morphing control, optimized by the multi-agent deep deterministic policy gradient for two-sweep control (MADDPG–VSC) algorithm. This approach enables real-time sweep angle adjustments based on current flight states, significantly enhancing aerodynamic efficiency and overall UAV performance. The precise motion state model for wing morphing developed in this study underpins the MADDPG–VSC algorithm’s implementation. The algorithm not only optimizes multi-UAV formation control efficiency but also improves obstacle avoidance, attitude stability, and decision-making speed. Extensive simulations and real-world experiments consistently demonstrate that the proposed algorithm outperforms contemporary methods in multiple aspects, underscoring its practical applicability in complex aerial systems. This study advances control technologies for morphing-wing UAV formation and offers new insights into multi-agent cooperative control, with substantial potential for real-world applications.

Advancing Automotive Displays: Liquid Crystal Cells for Precision Viewing Angle Adjustment

Advancing Automotive Displays: Liquid Crystal Cells for Precision Viewing Angle Adjustment

Bioinspired polylactic acid/polyethylene glycol @ silicon dioxide microfibrous tarpaulin with dual-layer heterogeneous structure for enhanced daytime radiative cooling

Fibrous tarpaulin serves as the core barrier that protects goods, people, or areas from the adverse impacts of the external environment, such as rain, dust, and sunlight. However, conventional tarpaulins exhibit inadequate mechanical properties, a low solar reflectance, and are susceptible to pollution. To address these issues, a bioinspired polylactic acid/polyethylene glycol @silicon dioxide (PLA/PEG@SiO₂) microfibrous tarpaulin with a dual-layer heterogeneous structure was fabricated via in-situ drafting melt-blowing combined with thermal bonding, inspired by the layered structure of shells. This bioinspired dual-layer heterogeneous structure, with an adjustable heterodyne angle and SiO₂ size gradient, significantly improved the mechanical performance of the PLA/PEG@SiO2 microfibrous tarpaulin, and specifically manifested as an increase in the bursting strength of the sample to 25.5 N. Moreover, PLA/PEG@SiO2 microfibrous tarpaulin demonstrated excellent anti-pollution properties, effectively repelling liquids and dust. Additionally, its radiative cooling efficiency was notably enhanced, achieving a temperature reduction of ~9.8 °C compared with conventional fabrics, with reflectance of ~88.6 % and emissivity of ~98.3 %. These findings suggest that dual-layered PLA/PEG@SiO₂ microfibrous tarpaulin with multifunctional capabilities is a promising candidate for radiative cooling in outdoor shelters, wearable cooling devices, and energy-efficient building insulation materials.

Optimization and Regulation Method for Large Blade-regulating Pump Stations Considering Safety Constraints

Abstract In plain areas, making flood control and drought resistance a heavy task. Large water pumping stations undertake the important task of water lifting and scheduling. Due to the physical characteristics of large pumping stations, they are often affected by the upstream and downstream water levels during water lifting scheduling, resulting in low head operating conditions. Low head operating conditions can easily cause pumping stations to operate at excessive power, thereby affecting the health of pumping station equipment. Based on the head efficiency curve of a large blade regulating pump station in this article, by optimizing the regulating mathematical model and considering constraints such as water level, flow rate, power, efficiency, and blade angle adjustment time interval under low head conditions, a dynamic programming calculation method is adopted to construct an optimized regulating method for the pump station. Based on real-time water level, various operating data of the unit are optimized to ensure the blade angle, power, and the flow rate and other parameters are all within the safety constraint range. And various operating data could be used to guiding the real-time optimization and adjustment of the pumping station, and additionally providing the operating foundation for the intelligent pumping station.

Application of operating scenarios and analysis of unstable flow characteristics at various angles of inlet guide vane.

In this study, we analyzed the performance characteristics of an axial flow pump with different angles of internally installed inlet guide vanes (IGVs). We predicted the pump's performance based on changes in the IGV angle and analyzed the impact of these angle variations on pump operation in the low-flow region. Additionally, we used real operational data from two sewage treatment plants to propose efficient operational scenarios. For turbulence flow analysis, the Reynolds-averaged Navier-Stokes equations were discretized based on the finite volume method. The grid formation was evaluated using the grid convergence index to select the optimal grid. Then, the internal flow was analyzed in detail through transient-state analysis. Through fast Fourier transform analysis, we confirmed that adjusting the IGV angle during pump operation in the low-flow region in response to load changes results in more stable operation compared with the existing method (valve control). Overall, our findings verified that energy reduction and efficient operation can be achieved through IGV angle adjustment compared with valve control.

Adjusted planning based on the joint line convergence angle improves correction accuracy in the standing position after opening wedge high tibial osteotomy

BackgroundPostoperative change of the joint line convergence angle (JLCA) is known to be a factor affecting correction error in opening wedge high tibial osteotomy (OWHTO). The purpose of this study was to assess whether preoperative planning that considers change of the JLCA can achieve accurate correction in the standing position after OWHTO.MethodsOWHTO was performed for 109 knees with osteoarthritis of the knee. The amount of angular correction was planned aiming to achieve mechanical valgus of 5° in 55 knees (conventional planning), and it was adjusted in 54 knees (adjusted planning) according to the preoperative JLCA as follows: not changed with JLCA ≤ 3°; decreased 1° with JLCA 4–6°; decreased 2° with JLCA 7–8°; and decreased 3° with JLCA ≥ 9°. The hip-knee-ankle (HKA) angle, JLCA, and medial proximal tibial angle (MPTA) were measured on standing long-leg radiographs. Correction error ≤ 2º was defined as the acceptable range, and correction error > 2º was defined as an outlier.ResultsThe conventional planning group had a significantly greater postoperative HKA angle than the adjusted planning group (6.1º and 4.9º, respectively). The mean JLCA decreased from 4.8º to 2.6º in the conventional planning group and from 4.6º to 2.7º in the adjusted planning group. The conventional planning group had significantly greater postoperative MPTA than the adjusted planning group (96.2º and 94.7º, respectively). The rate of outliers with correction error > 2º was significantly lower in the adjusted planning group (9%) than in the conventional planning group (24%). The rate of the MPTA > 95º was significantly lower in the adjusted planning group (30%) than in the conventional planning group (69%).ConclusionsThis study demonstrated that preoperative planning with adjustment of the correction angle according to the preoperative JLCA improved correction accuracy in the standing position after OWHTO.

The Role of Contrast-enhanced Ultrasound in the Femoral Head Perfusion Evaluation: A Pilot Study

ObjectivesWe explored the value of contrast-enhanced ultrasound (CEUS) in evaluating femoral head (FH) perfusion, guiding interventions and follow-up for infants with developmental dysplasia of the hip (DDH) and septic arthritis of the hip (SAH). The aim was to provide robust evidence for clinical assessment. MethodsTen infants, including 7 with DDH and 3 with SAH, were prospectively enrolled, with their bilateral hips alternately scanned during the CEUS exams. Twenty hips were classified into the case group (n = 11) and the control group (n = 9). Pre- and post-interventional studies were performed in DDH infants requiring interventions. FH perfusion was assessed by the perfusion area ratio (PAR) and quadrant location of microbubble-defect regions. ResultsIn the case group, 25 CEUS studies were conducted, including 11 baseline, 7 follow-up and 7 post-intervention studies. The PAR significantly decreased in the case group (49.79% vs. 100.00%, p < 0.05). The microbubble-defect regions averagely affected 2 quadrants, primarily quadrat No. 3 (30%) and No. 4 (32%). Seven hip abduction angle adjustments were made based on pre-interventional studies, resulting in a significant increase in PAR in post-interventional studies (37.63% vs. 60.24%, p < 0.05). PAR increased in follow-up studies compared to baseline values (45.61% vs. 76.07%, p < 0.05). The inter- and intra-observer reproducibility of PAR measurements were excellent (intraclass correlation coefficient, both 0.97). ConclusionCEUS proves to be a promising technique for quantitatively detecting FH perfusion in DDH and SAH infants with high reproducibility. It is valuable for baseline, intra-intervention and follow-up studies, aiming in clinical conditions and therapeutic effect evaluation.

Design and Preliminary experiment of an Off-axis aequilate-mirrors linear Fresnel concentrator with sunlight self-adaptive feature

The Off-Axis Linear Fresnel Reflector (LFR) is an innovative, compact solar concentrator designed to reduce device height and wind-load without compromising efficiency. It is crucial in applying LFR devices to applications such as building façades. To this aim, The Off-axis LFR design is introduced to addressing the inter-mirror blocking issue that diminishes the efficiency of conventional LFRs. Initially, an optimized Aequilate-mirrors design was proposed to reduce manufacturing complexity and cost. Subsequently, a crank-slider mechanism was introduced as a solution to the issue of inconsistent angle adjustment among the mirrors. Additionally, the paper details the sunlight self-adaptive feature of the Off-axis LFR concentrator, where the LFR mirrors can independently rotate to track the sun’s position, adaptively altering the mirror array’s profile and sunward aperture. This feature maximizes the device’s sunlight harvesting capacity, particularly in angled sunlight conditions. A prototype of the Off-axis LFR device was designed and built for assessment, featuring a focus length of just 78 mm and an overall 145 mm housing height. The paper then discusses how the sunlight self-adaptive features enhance the efficiency during the early morning and twilight hours. Comprehensive testing, including mechanical driving, laser focusing, and outdoor full-function verification, was conducted. Ultimately, comparative photo-thermal efficiency tests with a similarly sized conventional LFR concentrator demonstrated that the Off-axis LFR concentrator could achieve a significant increase in efficiency, with an all-day average thermal efficiency improvement of over 10 %. Based on the previous theoretical study, this study has completed the engineering prototype design and validation. And confirmed a thermal concentration efficiency of 44.36 % within a height of 145 mm in experiments.