Direction Angle Research Articles

Field measurement-based research on wind pressure interference effects of tracking photovoltaic arrays

Field measurement-based research on wind pressure interference effects of tracking photovoltaic arrays

The Qibla Direction Problem in Large-Scale Maps and Its Representation with Geodetic Accuracy: The Case of Türkiye

In Islamic societies, knowing the direction of the Qibla is important in the planning of religious areas. In urban plans designed by practitioners where the Qibla direction is not considered, inconsistencies arise among religious areas. These inconsistencies reduce the project areas within the structures and cause loss of space. To address these inconsistencies, plan revisions are required. However, plan revisions extend the construction periods of projects and increase the projected costs. Adding the Qibla direction as a legend to large-scale maps (LSMs) used as base maps in the drawing of urban plans is an option that can be used to eliminate these inconsistencies. In this study, the Qibla direction for all LSMs in Türkiye's national mapping was calculated with geodetic accuracy to eliminate the mentioned inconsistencies. These calculations and the generated visual outputs are presented to users through the Map Qibla Direction Calculation Interface (MQDCI) developed in the MATLAB environment. When any coordinate data or the name of the relevant LSM is entered as input into the developed interface, the Qibla direction value for that map is provided to the user in this study. The developed interface allows the Qibla direction angle to be calculated and presented to the user with geodetic accuracy and instantly, without the need for measurements and calculations performed in the field. Although the developed interface is designed according to the Kaaba, which is the Qibla for Muslims, and Türkiye's geographical boundaries, it is also suitable for other religions in Türkiye or different religions in other countries. For this, it is sufficient to know the national mapping systems of the countries and the geographical coordinates of the Qibla in Christianity and Judaism

Inclined Aerial Image and Satellite Image Matching Based on Edge Curve Direction Angle Features

Optical remote sensing images are easily affected by atmospheric absorption and scattering, and the low contrast and low signal-to-noise ratio (SNR) of aerial images as well as the different sensors of aerial and satellite images bring a great challenge to image matching. A tilted aerial image and satellite image matching algorithm based on edge curve direction angle features (ECDAF) is proposed, which accomplishes image matching by extracting the edge features of the images and establishing the curve direction angle feature descriptors. First, tilt and resolution transforms are performed on the satellite image, and edge detection and contour extraction are performed on the aerial image and transformed satellite image to make preparations for image matching. Then, corner points are detected and feature descriptors are constructed based on the edge curve direction angle. Finally, the integrated matching similarity is computed to realize aerial–satellite image matching. Experiments run on a variety of remote sensing datasets including forests, hills, farmland, and lake scenes demonstrate that the effectiveness of the proposed algorithm shows a great improvement over existing state-of-the-art algorithms.

Study of the motion and interaction of micro-swimmers with different scales in Poiseuille flow

Study of the motion and interaction of micro-swimmers with different scales in Poiseuille flow

Dynamics of zinc dendritic growth in aqueous zinc-based flow batteries: Insights from phase field-Lattice-Boltzmann simulations

Dynamics of zinc dendritic growth in aqueous zinc-based flow batteries: Insights from phase field-Lattice-Boltzmann simulations

Automatic control technology of mechanical equipment based on microelectronic sensing signal control

The purpose of the research is to implement a master-slave control system for hand virtual-real interaction, which can capture the position, direction and finger joint angle of the user’s hand in real-time. After being analyzed, the original mot analyzed goes through limiting and removing joggle procedures, integrating the complementary filter algorithm and obtaining a drive database based on the Kalman filter algorithm. The data is used to drive the virtual hand to interact with the virtual environment, with the Roll, Pitch and Yaw being [Formula: see text]0.1∘, [Formula: see text]0.15∘, [Formula: see text]0.15∘, respectively. These data prove that the data processing algorithm is compatible with the system hardware platform regarding accuracy and noise reduction. In the process of building the virtual model, under the premise of satisfying a certain number of meshes, the texture mapping of the hand model not only satisfies the fidelity of the virtual hand model but also makes the model less complex and interactive. This helped solve the fragile joint connection problem when the finger was bent. In the subsequent interaction experiment, the system was tested with static gestures and dynamic grasping, and the experimental data and interaction effect showed that the system had good interactivity and stability.

Numeric analysis of elastic plane body static problem by the method of matched sections

The paper continues the series of authors' works on the elaboration of a principally new variant of the finite element method, FEM, for the treatment of various problems of mathematical physics, namely the method of matched section, MMS. The elastic plane body under static loading is considered here. As in FEM, the whole body is meshed into the small elements of, preferably, rectangular form. The main peculiarity of the method consists in the introduction of a set of main parameters dependent only on one coordinate variable, i.e. either or . So, any differential equilibrium equation with two partial derivatives concerning or is broken out into two relatively simple equations concerning only one independent variable. This leads to the introduction of one additional constant showing the interchange between these two equations. The introduced constants can be derived from the equation of continuity of kinematic parameters in the center of each element. The main, for example, -dependent parameters are: and displacements in vertical (-) and horizontal (-) directions, respectively; normal and tangential (shear) forces in direction, and direction, respectively; and bending moment and angle of rotation . Similar parameters are established for -direction. Based on the methodology of the transfer matrix method the analytical matrix-form dependence between these parameters in any point or and those at the lower and/or left border of the element are established. For the treatment of oblique and curvilinear boundaries, the right triangular element as a special degenerate case of the rectangular element is derived. The resulting system of linear equations is formulated for unknownThe paper continues the series of authors' works on the elaboration of a principally new variant of the finite element method, FEM, for the treatment of various problems of mathematical physics, namely the method of matched section, MMS. The elastic plane body under static loading is considered here. As in FEM, the whole body is meshed into the small elements of, preferably, rectangular form. The main peculiarity of the method consists in the introduction of a set of main parameters dependent only on one coordinate variable, i.e. either or . So, any differential equilibrium equation with two partial derivatives concerning or is broken out into two relatively simple equations concerning only one independent variable. This leads to the introduction of one additional constant showing the interchange between these two equations. The introduced constants can be derived from the equation of continuity of kinematic parameters in the center of each element. The main, for example, -dependent parameters are: and displacements in vertical (-) and horizontal (-) directions, respectively; normal and tangential (shear) forces in direction, and direction, respectively; and bending moment and angle of rotation . Similar parameters are established for -direction. Based on the methodology of the transfer matrix method the analytical matrix-form dependence between these parameters in any point or and those at the lower and/or left border of the element are established. For the treatment of oblique and curvilinear boundaries, the right triangular element as a special degenerate case of the rectangular element is derived. The resulting system of linear equations is formulated for unknown values of all parameters specified at the border of all elements. The efficiency and the superb accuracy of the MMS are demonstrated in the classical examples of bending of a long rectangular body (beam-like geometry) and tension at infinity of a 2D body with a small circular hole values of all parameters specified at the border of all elements. The efficiency and the superb accuracy of the MMS are demonstrated in the classical examples of bending of a long rectangular body (beam-like geometry) and tension at infinity of a 2D body with a small circular hole.

Analysis of Acoustic Surface Wave Focused Unidirectional Interdigital Transducers Using Coupling-of-Mode Theory.

In cell or droplet separation, high acoustic wave energy of a surface acoustic wave (SAW) device is required to generate sufficient acoustic radiation force. In this paper, the electrode width-control floating electrode focused unidirectional interdigital transducer (EWC-FEFUDT) is proposed due to its enhanced focusing properties. The performance of the EWC-FEFUDT is investigated using the Coupling-of-Mode (COM) theory, and the COM parameter is extracted using the Finite Element Method (FEM). The four different forbidden band edge frequencies account for the unidirectionality of the proposed EWC-FEFUDT. A direction angle of ϕκ-ϕζ=44.5° of the EWC-FEFUDT (Design 3) is obtained, being fairly close to the optimum value of 45°. The EWC-FEFUDT (Design 3) has a lower insertion loss (IL) of -5.1 dB and greater unidirectionality (20 × log10(D) = 13.8 dB). The SAW maximum amplitude of the EWC-FEFUDT (Design 3) is increased by about 1.5×10-4 µm compared to that of the focused interdigital transducers (FIDTs). The maximum acoustic pressure of the EWC-FEFUDT is an order of magnitude higher than that of FIDTs. The EWC-FEFUDT exhibits enhanced focusing properties. The proposed EWC-FEFUDT may provide an alternative method for cell or droplet separation in an efficient manner.

Effects of functional type and angular configuration on reflectance anisotropy of aquatic vegetation in ultra-high resolution hyperspectral imagery

ABSTRACT Imaging spectroscopy and lightweight unmanned aerial vehicles (UAVs) have revolutionized remote sensing of vegetation, by providing high spectral and spatial resolution data. Comprehensive wetland monitoring should be based on reliable mapping of biophysical aquatic vegetation parameters, which in turn requires low bias in measured spectra, e.g. minimization of reflectance anisotropy. This study aims to quantitatively investigate how sensor scan direction and solar zenith angle (SZA) affect vegetation spectra over two dominant aquatic plants, Phragmites australis and Nuphar lutea, representing different functional types (i.e. emergent and floating) with divergent canopy structure and affinity with water, using data collected with a hyperspectral (400–1000 nm range) push-broom sensor mounted on a UAV. Anisotropy factor (ANIF), mean reflectance scatterplots and regression analysis were used for assessing the magnitude of spectral anisotropy at both pseudo-leaf and canopy scales. Our findings showed more accentuated anisotropic behaviour in the visible than near-infrared domain at SZA < 60° as the scan direction approaches that of solar principal plane. The increase in reflectance in near-forward direction affects the spectra of floating-leaved N. lutea at both leaf and canopy scales, suggesting the presence of water (as a film over leaves or as canopy background) as a likely anisotropy driver. Backward hotspot is evident in canopy spectra of emergent P. australis, with driving mechanisms similar to terrestrial species (i.e. shadow-hiding). At SZA > 60°, reflectance anisotropy appears to be negligible, independent of functional type and scan direction. This research underscores the importance of considering sun-target-sensor geometry in remote sensing studies on aquatic vegetation.

Comparison of fatigue lifetime of new generation CAD/CAM crown materials on zirconia and titanium abutments in implant-supported crowns: a 3D finite element analysis.

Due to the dynamic character of the stomatognathic system, fatigue life experiments simulating the cyclic loading experienced by implant-supported restorations are critical consideration. The aim of this study was to examine the effect of different crown and abutment materials on fatigue failure of single implant-supported crowns. Models were created for 10 different designs of implant-supported single crowns including two zirconia-reinforced lithium silicates (crystallized and precrystallized), monolithic lithium disilicate, polymer-infiltrated ceramic networks, and polyetheretherketone supported by zirconia and titanium abutments. A cyclic load of 179 N with a frequency of 1 Hz was applied on palatal cusp of a maxillary first premolar at a 30° angle in a buccolingual direction. In the models with titanium abutments, the polymer-infiltrated ceramic network model had a lower number of cycles to fatigue failure values in the implant (5.07), abutment (2.30), and screw (1.07) compared to others. In the models with zirconia abutments, the crystallized zirconia-reinforced lithium silicate model had a higher number of cycles to fatigue failure values in the abutment (8.52) compared to others. Depending on the fatigue criteria, polyetheretherketone implant crown could fail in less than five year while the other implant crowns exhibits an infinite life on all models. The type of abutment material had an effect on the number of cycles to fatigue failure values for implants, abutments, and screws, but had no effect on crown materials. The zirconia abutment proved longer fatigue lifetime, and should thus be considered for implant-supported single crowns.

Influence of SV Wave Oblique Incidence on the Dynamic Response of Arch Dams Under Canyon Contraction

Current dynamic response analyses of arch dams under an oblique incidence of seismic waves have overlooked the effects of canyon contraction deformation. This study investigated the influence of the incident direction and incident angle of seismic waves on the comprehensive displacements, as well as the damage, of arch dams under canyon contraction conditions. When SV waves are incident obliquely along the river direction, the peak displacements of the dam crest and arch crown beam increase with increasing canyon contraction. The displacement of the dam reaches its maximum when the incident angle is 0°, indicating that the SV wave vertical incidence is the most unfavourable incidence mode affecting the displacement. Dam damage cracking is most severe in the case of a canyon contraction of 60 mm and an incidence angle of 0°. The dam damage cracking index in this case increases only by 7.6% compared to a canyon contraction of 0 mm and an angle of incidence of 0°. However, the change in canyon contraction when a seismic wave is incident obliquely can cause serious damage cracking to the dam. When the SV wave is incident obliquely along the cross-river direction, the dam damage cracking index in this case increases by 110% compared to the case where the canyon contraction is 0 mm, and the incidence angle is 0°. Therefore, it is necessary to comprehensively consider the influences of canyon contraction and the oblique incidence of seismic waves in the seismic design and safety review of arch dams.

The Structural Design and Analysis of the Multi Nozzle Relay Air-Jet Inserting System by Profile Reed Guiding for 3D Weaving Machine

Introduction: Based on the literature, this article designs a parameterized simulation model of a multi-layer jet weft insertion system by profiles reed guidance for a 3D loom on the PTC Creo9.0 platform, including the main supersonic nozzle, supersonic auxiliary nozzle (relay nozzle), and multi-slot profiles reed components. Method: Based on the existing basic theory, experimental results, and empirical data of turbulent jet, the parameters of the multi-layer jet weft insertion system, as well as the structural parameters and the relative positions of the main, auxiliary nozzle and profile reed components, such as the center distance of each layer's main nozzle, auxiliary nozzle spacing, auxiliary nozzle installation angle, spray direction angle, and spray angle, have been determined preliminarily. Result: Further, the basic flow field parameters, such as the supply pressure of the main and auxiliary nozzles and the shape of multi-layer profile reeds, have been determined optimally on the Virtual Prototype Collaborative Simulation Platform (PTC Creo9.0/ANSYS Workbench/Fluent 2024R1), and the rationality of the structural design also been verified; on the premise of ensuring that the airflow velocity of each layer's profiles groove meets the requirements of weft insertion, the design and simulation calculation is repeatedly modified, and the optimal structural design parameters of the multi-layer weft insertion system and nozzle is finally determined. Conclusion: To explore the feasibility of multi-layer jet weft insertion, the design of threedimensional multi-layer jet weft insertion looms has laid a theoretical foundation, laying a good foundation for the emergence and industrial manufacturing of three-dimensional multi-layer jet weft insertion looms, and providing an important reference for the innovative design of threedimensional multi-layer water jet weft insertion looms.

Evaluation and correction methods for geometric errors of hydrostatic thrust bearings

The value and direction angle of the perpendicularity error of the thrust surface and bearing bush in hydrostatic thrust bearings directly affect the motion accuracy. In this paper, a rapid onsite measurement method and evaluation model for the value and direction angle of the perpendicularity error of the thrust surface and bearing bush in hydrostatic thrust bearings are presented. The method is validated by comparing experimental measurements with those obtained using a CMM. An analysis of the perpendicularity errors before and after correction shows that at different speeds (10 rpm, 30 rpm, and 50 rpm), the errors in the mean axial and tilt displacements of the thrust bearing are reduced by 68.41% and 35.44%, respectively.

Optimizing the Separation Process of Difficult-to-Separate Wheat and Barley Grain Mixtures Using Vibrofriction Technology

Abstract The study explores the feasibility of using a block-modular vibrofriction separator with non-perforated surfaces to efficiently separate challenging mixtures of wheat and barley grains. The research identifies key parameters influencing the separation process, including vibration amplitude, frequency, direction, and the inclination angles of the separating surfaces. Optimal settings-vibration amplitude of 0.9 mm, frequency of 95 Hz, vibration direction angle of 30°, and longitudinal inclination angle of 11°—were determined to achieve high separation efficiency. The process enables the division of grain mixtures into fractions with varying wheat and barley content, suitable for different applications: seeds, bread flour, and polycomposite mixtures for bakery products. The proposed separation approach significantly enhances productivity and minimizes loss, offering practical recommendations for the food and grain processing industries.

Research on damage assessment and visualization technology of anti-ship missiles on typical ships

Abstract To improve the damage assessment efficiency of anti-ship weapons, the target vulnerability model of typical ships is introduced, and the damage level is classified into severe and moderate damage according to the functional characteristics of the ships. The damage probability calculation model of typical ships is constructed, and the damage assessment system of anti-ship missiles on typical ships is built based on the Unity3D engine. The system can achieve the parameter input of the anti-ship missile, the calculation of the damage probability of the anti-ship missile on typical ships, and the visualization of the damaging effect. For an example of an anti-ship missile analysis, the system visualizes the damage effect of the anti-ship missile on a typical ship, sets the combat tribal speed to 1, 450 m/s and CEP to 10 m, and calculates the damage probability of the anti-ship missile on a typical ship at three different aiming points under the conditions of the bullet-eye meeting with the direction angle of the scattering of fragments of 90° and the angle of fall of 20°. The results show that aiming point 2 has the highest probability of destroying the ship. The designed system is functionally complete and can provide support for the damage assessment of typical ships by anti-ship missiles, and the idea of system development can provide a reference for the design of damage assessment software.

Considering the Bottom Edge Cutting Effect of the Carbon Fiber Reinforced Polymer Milling Force Prediction Model and Optimization of Machining Parameters.

The milling force plays a pivotal role in CFRP milling. Modeling of the milling force is helpful to explore the changing law, optimize the processing parameters, and then reduce the appearance of defects. However, most of the existing models ignore the effect of the bottom edge. In this paper, the prediction of milling force in CFRP milling processes is taken as the research object. By analyzing the milling mechanism and considering the end milling cutter's bottom cutting edge, the prediction model of milling force was established. Based on the experimental data and simulation data of milling force, the milling force coefficient was obtained by inverse calculation. Subsequently, the predicted cutting force was compared with the experimental cutting force, showing a maximum error of 14.5%, which is within a reasonable range, and the correctness of the model was verified. Furthermore, combined with the delamination damage and the milling force prediction model, a multi-objective optimization model of milling parameters was established, and the genetic algorithm was used to solve the model. The unidirectional carbon fiber plate with a fiber direction angle of 45° was selected as the optimization example. The minimum delamination damage was obtained under the cutting conditions of a spindle speed of 4903.1569 r/min, feed rate per tooth of 0.01 mm/z, and an axial depth of cut of 0.5 mm, and the experimental verification was carried out. The feasibility of the genetic algorithm in CFRP milling parameter optimization modeling was also verified.

Implicit motor adaptation patterns in a redundant motor task manipulating a stick with both hands.

The remarkable ability of the motor system to adapt to novel environments has traditionally been investigated using kinematically non-redundant tasks, such as planar reaching movements. This limitation prevents the study of how the motor system achieves adaptation by altering the movement patterns of our redundant body. To address this issue, we developed a redundant motor task in which participants reached for targets with the tip of a virtual stick held with both hands. Despite the redundancy of the task, participants consistently employed a stereotypical strategy of flexibly changing the tilt angle of the stick depending on the direction of tip movement. Thus, this baseline relationship between tip-movement direction and stick-tilt angle constrained both the physical and visual movement patterns of the redundant system. Our task allowed us to systematically investigate how the motor system implicitly changed both the tip-movement direction and the stick-tilt angle in response to imposed visual perturbations. Both types of perturbations, whether directly affecting the task (tip-movement direction) or not (stick-tilt angle around the tip), drove adaptation, and the patterns of implicit adaptation were guided by the baseline relationship. Consequently, tip-movement adaptation was associated with changes in stick-tilt angle, and intriguingly, even seemingly ignorable stick-tilt perturbations significantly influenced tip-movement adaptation, leading to tip-movement direction errors. These findings provide a new understanding that the baseline relationship plays a crucial role not only in how the motor system controls movement of the redundant system, but also in how it implicitly adapts to modify movement patterns.

Implicit motor adaptation patterns in a redundant motor task manipulating a stick with both hands

The remarkable ability of the motor system to adapt to novel environments has traditionally been investigated using kinematically non-redundant tasks, such as planar reaching movements. This limitation prevents the study of how the motor system achieves adaptation by altering the movement patterns of our redundant body. To address this issue, we developed a redundant motor task in which participants reached for targets with the tip of a virtual stick held with both hands. Despite the redundancy of the task, participants consistently employed a stereotypical strategy of flexibly changing the tilt angle of the stick depending on the direction of tip movement. Thus, this baseline relationship between tip-movement direction and stick-tilt angle constrained both the physical and visual movement patterns of the redundant system. Our task allowed us to systematically investigate how the motor system implicitly changed both the tip-movement direction and the stick-tilt angle in response to imposed visual perturbations. Both types of perturbations, whether directly affecting the task (tip-movement direction) or not (stick-tilt angle around the tip), drove adaptation, and the patterns of implicit adaptation were guided by the baseline relationship. Consequently, tip-movement adaptation was associated with changes in stick-tilt angle, and intriguingly, even seemingly ignorable stick-tilt perturbations significantly influenced tip-movement adaptation, leading to tip-movement direction errors. These findings provide a new understanding that the baseline relationship plays a crucial role not only in how the motor system controls movement of the redundant system, but also in how it implicitly adapts to modify movement patterns.

Effect of resultant force direction in single point diamond turning of (111)CaF2

Effect of resultant force direction in single point diamond turning of (111)CaF2

Numerical assessment of incoming atmospheric boundary layer effects generated by various approaches on ship airwake turbulence characteristics

Numerical assessment of incoming atmospheric boundary layer effects generated by various approaches on ship airwake turbulence characteristics