Calculation Of Angle Research Articles

Three-dimensional coupled-mode model and characteristics of low-frequency sound propagation in ocean waveguide with seamount topography

Large-scale topography, such as a seamount, substantially impacts low-frequency sound propagation in an ocean waveguide, limiting the application of low-frequency acoustic detecting techniques. A three-dimensional (3D) coupled-mode model is developed to calculate the acoustic field in an ocean waveguide with seamount topography and analyze the 3D effect. In this model, a correction is introduced in the bottom boundary, theoretically making the acoustic field satisfy the energy conservation. Furthermore, a large azimuth angle calculation range is obtained by using the operator theory and higher-order Padé approximation. Additionally, the model has advantages related to the coupling mode and parabolic equation theory. The couplings corresponding to the effects of range-dependent environment are fully considered, and the numerical implementation is kept feasible. After verifying the accuracy and reliability of the model, low-frequency sound propagation characteristics in the seamount environment are analyzed. The results indicate lateral variability in bathymetry can lead to out-of-plane effects such as the horizontal refraction phenomenon, while the coupling effect tends to restore the abnormal sound field and produces acoustic field diffraction behind the seamount. This model effectively considers the effects of the horizontal refraction and coupling, which are proportional to the scale of the seamount.

Design and test of a distributed control system of weeding robot based on multi-STM32 and CAN bus

Aiming at the problems of a single control mode, complex signal line, serious interference and poor system stability of a traditional weeding machine, a distributed control idea was proposed. Based on STM32 as the main control chip, each control unit realizes motion control, detection control, command control, and the terminal was displayed in a centralized manner. Based on ISO11783 protocol, according to the actual requirements of the weeding robot, the CAN bus communication protocol was improved and formulated to form a distributed control system. The system can completely realized all the actions of the weeding robot. 1. Motion controls: robot forwards, backwards, turning and weeding knife up or down; 2. Detection feedback: a power chassis climbing angle calculation and weeding knife speed self-adjustment, battery power, engine fuel capacity display; 3. Control command input functions. The test results had shown that the control system is stable, responsive solid, design specifications. It could meet the requirements of practical application. Meanwhile, the real-time accuracy and reliability of a CAN bus application in the agricultural production control system were verified.

Design and development of Spaiser remotely operated vehicle

Design of new unmanned underwater vehicles (UUVs) is a continuous process since decades, where finding an optimal design for a specific application is still a challenging subject. New inspection class category remotely operated vehicle (ROV) is developed to overcome some disadvantages of existing ROVs of the same category. It has been taken into consideration in the new design to be small, capable of maneuvering freely in 6 DOF, closed-hull body of minimum water resistive forces, low-cost components which work with high integration, one-duct tether (at low cost) and software program to be used with any PC instead of special control station. Detailed design of the internal network that combines sensors, thrusters’ controllers, and camera of the ROV is shown and smart communication architecture between the ROV and the control station is also introduced. Finally, in the computer layer, many aspects are discussed including communication protocol between the control station and the ROV, high-precision orientation angles calculation using inertial measurement unit (IMU), heading calculation of the ROV, and GUI of the control station.

A three-dimensional damage analysis framework for fiber-reinforced composite laminates

While fiber-reinforced composites are increasingly applied as structural components due to superiority in lightweight and robust mechanical performance, reliable and efficient numerical assessment is often essential for supporting such applications and can even stand in lieu of testing, yet uncertainties and controversies remain despite continuous efforts over decades. To address the deficiency, a three-dimensional (3D) damage analysis framework based on the method of finite elements (FE) was proposed to predict the initiation and evolution of damage as well as the load-bearing capacity of a laminated composite structure subjected to general loadings. Within the analysis framework, stress interaction and coupling effect were embedded in failure criteria and damage evolution laws. With both geometric nonlinearity and shear nonlinearity accounted for, a smeared constitutive damage model circumventing the longstanding problem of FE mesh dependency was formulated. Built upon the strength theory of fiber kinking, calculation of initial misalignment angle was explicitly determined. Further, to determine the damage variables, stress contributions to energy dissipation during crack initiation and growth were considered. Selected verification studies, including transverse compression and open-hole compression, demonstrated excellent agreement of numerical predictions with existing experimental results. The proposed 3D damage analysis framework can reproduce the expected failure mechanisms, strength, stress distributions and structural load-bearing capacity of fiber-reinforced composite laminates.

Rapid Prediction of Seismic Incident Angle’s Influence on the Damage Level of RC Buildings Using Artificial Neural Networks

The angle of seismic excitation is a significant factor in the seismic response of RC buildings. The procedure required for the calculation of the angle for which the potential seismic damage is maximized (critical angle) contains multiple nonlinear time history analyses, each using different angles of incidence. Moreover, the seismic codes recommend the application of more than one accelerogram for the evaluation of seismic response; thus, the whole procedure becomes time consuming. Herein, a method to reduce the time required for the estimation of the critical angle based on multilayered feedforward perceptron neural networks is proposed. The basic idea is the detection of cases in which the critical angle increases the class of seismic damage compared to the class that arises from the application of the seismic motion along the buildings’ structural axes. To this end, the problem is expressed and solved as a pattern recognition problem. The ratios of seismic parameters’ values along the two horizontal seismic records’ components, as well as appropriately chosen structural parameters, were used as the inputs of the networks. The results of analyses show that the neural networks can reliably detect the cases in which the calculation of the critical angle is essential.

Three-dimensional shear angle determination with application to shear-frame test

The shear frame test is very often used in the context of plastics engineering to examine only the fiber construction for its deformability. Here, it is common to assume a homogeneous deformation, which apparently exists as a global deformation due to the shear frame. This results in the assumption of a constant overall shear angle. In this paper, we compare two analytical approaches to describe the deformation and the resulting strains in detail, particularly, the local shear angle calculation. As a second step, the extension of the shear angle computation based on curvilinear, three-dimensional surface deformations is applied to optical results of the experimental deformation behavior. For this purpose, a three-dimensional image correlation system is drawn on to determine the local, tangential shear angle even for folded fabrics. This requires an approach which is different to the classical digital image correlation method since the speckle varnish influences the deformation of the very compliant fiber bundles. In a third step, the same procedure is applied to the results of three-dimensional finite element computations since the programs do not provide the shear angle measure. The shear angle determination is discussed at various examples. As a side result of the investigations, the material parameters for orthotropic elasticity are determined using a representative volume element approach exploiting μ-CT data. Although the wrinkling prediction calculations depend on the pre-deformation, finite element discretization, and uncertainties of the specimens, calculation results might be used as an indicator to improve the specimen geometries.

Development of a Computational Tool for the Estimation of Alveolar Bone Loss in Oral Radiographic Images

The present study evaluated a newly developed computational tool (CT) to assess the alveolar bone space and the alveolar crest angle and compares it to dentist assessment (GT). The novel tool consisted of a set of processes initiated with image enhancement, points localization, and angle and area calculations. In total, we analyzed 148 sites in 39 radiographic images, and among these, 42 sites were selected and divided into two groups of non-periodontitis and periodontitis. The alveolar space area (ASA) and alveolar crest angle (ACA) were estimated. The agreement between the computer software and the ground truth was analyzed using the Bland–Altman plot. The sensitivity and specificity of the computer tool were measured using the ROC curve. The Bland–Altman plot showed an agreement between the ground truth and the computational tool in all of the parameters assessed. The ROC curve showed 100% sensitivity and 100% specificity for 12.67 mm of the alveolar space area. The maximum percentage of sensitivity and specificity were 80.95% for 13.63 degrees of the alveolar crest angle. Computer tool assessment provides accurate disease severity and treatment monitoring for evaluating the alveolar space area (ASA) and the alveolar crest angle (ACA).

Numerical Simulation of Solids Conveying in Grooved Feed Sections of Single Screw Extruders.

For plastic processing extruders with grooved feed sections, the design of the feed section by means of analytical calculation models can be useful to reduce experimental costs. However, these models include assumptions and simplifications that can significantly decrease the prediction accuracy of the throughput due to complex flow behavior. In this paper, the accuracy of analytical modeling for calculating the throughput in a grooved barrel extruder is verified based on a statistical design of experiments. A special focus is placed on the assumptions made in the analytics of a backpressure-independent throughput, the assumption of a block flow and the differentiation of the solids conveying into different conveying cases. Simulative throughput tests with numerical simulation software using the discrete element method, as well as experimental throughput tests, serve as a benchmark. Overall, the analytical modeling already shows a very good calculation accuracy. Nevertheless, there are some outliers that lead to larger deviations in the throughput. The model predominantly overestimates the throughputs, whereby the origin of these deviations is often in the conveying angle calculation. Therefore, a regression-based correction factor for calculating the conveying angle is developed and implemented.

Real-time panoramic-deformation measurement of cabin structure of launch vehicle based on camera network

<p indent="0mm">To satisfy the requirement of real-time panoramic-deformation measurement of a cabin structure in a large-diameter launch vehicle, a camera-network deformation-measurement system composed of 24 cameras and real-time three-dimensional (3D) deformation-measurement software based on CPU parallel computing was developed. The 360° full-circle deformation measurement of the inner surface of a cylindrical coordinate system and real-time measurement of the local deformation of a local Cartesian coordinate system were successfully realized. The camera-network measurement system consisted of 12 sets of binocular systems. The field of view of a single set of binocular systems was 3.6 m×3.6 m, and a certain overlap area was set between two adjacent binocular systems to ensure continuity of measurements. Photogrammetry and binocular stereo vision were used to reconstruct the 3D coordinates of the coded points, and coordinate transformation between the local and global coordinate systems was realized using the coded points. Finally, coordinate unification of the 12 sets of binocular systems was performed. A single set of binocular systems could be connected to a computer. By implementing the seed-point-based parallel algorithm and initial guess-estimation-algorithm-based deformation-transfer scheme, real-time 3D displacement and surface-strain measurements at 70000 points per second were successfully realized. On the basis of the 360° full-circle deformation-measurement results in the cylindrical coordinate system, high-precision calculation of the diffusion angle was successfully realized. The standard deviation of the static noise in the three directions was less than 0.01 mm, and the standard deviation of the static noise in the strain was less than 50 microstrains.

Hopf Fibration on Relationship Between Dihedral Angle θ&amp;lt;sub&amp;gt;HnHn+1&amp;lt;/sub&amp;gt;[deg] and Vicinal Angle ϕ[deg], Angles Calculated from NMR Data with 3-Shere Approach and Java Script

3-Sphere theory, a hypersphere in four dimensions, is applied for calculation dihedral angles with the right stereochemistry and sign in D, -L ribitol series from proton and carbon chemical shift (Δδ_XnXn+1[ppm], X = H, C) and vicinal coupling constant (³<i>J</i>_HnHn+1[Hz]) with Java Script. A method in three steps, easy to calculate by hand or with Java Script program: 1. prediction of the dihedral angle only from ³<i>J</i>_HnHn+1[Hz], 2. calculation the angle of set A with manifold equation (conic section, Villarceau circles) from chemical shift, 3. building of the seven sets unit or six sets units, from which is chose an angle almost equal with the predicted one having its stereochemistry and sign. Angles of set A and set B, relationships between vicinal angle and dihedral angle (X₀-X₁₅) are introduced instead of polar angle and azimuthal angle in spherical coordinates (eq. 1 <i>versus</i> eq. 3). Hopf coordinates, trigonometric equations, confirmed by algebraic equations are disclosed for all <i>cis</i>-ae/ea, <i>trans</i>-ee, <i>trans-aa</i> stereochemistry. Octonionic fibration S⁷→S¹⁵→S⁸ in R¹⁶, with real fibration S⁰ →S¹ →S¹ as unit, reassembles all possible stereochemistry gives by the HCCH fragment on two congruent disks, each centered on the perimeter of the other with equilateral triangles as vertices. Complex Hopf fibration in R⁴ ensuring the calculation of the dihedral angle from vicinal angle and <i>vice versa</i>, demonstrating the relationships between sets A, B, C.

Weak deflection angle of Kazakov–Solodukhin black hole in plasma medium using Gauss–Bonnet theorem and its greybody bonding

In this paper, we study light rays in a Kazakov-Solodukhin black hole. To this end, we use the optical geometry of the Kazakov-Solodukhin black hole within the Gauss-bonnet theorem. We first show the effect of the deformation parameter $a$ on the Gaussian optical curvature, and then we use the modern method popularized by Gibbons and Werner to calculate the weak deflection angle of light. Our calculations of deflection angle show how gravitational lensing is affected by the deformation parameter $a$. Moreover, we demonstrate the effect of a plasma medium on weak gravitational lensing by the Kazakov-Solodukhin black hole. We discuss that the increasing the deformation parameter $a$, will increase the weak deflection angle of the black hole. Our analysis also uncloak how one may find a observational evidence for a deformation parameter on the deflection angle. In addition, we studied the rigorous bounds of the Kazakov-Solodukhin black hole for the grey body factor and also studied the graphical behaviour of the bounds by fixing $l=0$ and $M=1$ and observed that increasing the deformation parameter $a$ will decrease the rigorous bound $T_b$ of the black hole.

Aircraft Position Prediction during the Crosswind Approach

Testing the impact of the drag coefficient on an F16 aircraft model, depending on the angle of attack a was performed. First, a navigation model was introduced describing the preliminary and computational assumptions of the model. The final part of the present paper contains the relationships between the wind angle and the wind correction angle at the angle of attack a = 00, a = 110, a = 130 for a full-scale F-16 aircraft. The tables present results of all the calculations for individual angles of attack, taking into account variable wind angles relative to the longitudinal axis of the runway. The values show the corrections calculated for an 1/19 scale aircraft model and for a full-scale F16 aircraft. The "right" and "left" designations represent the direction from which the wind blows in relation to the aircraft.

A Commutation Failure Prediction and Mitigation Method

The mitigation of commutation failure (CF) depends on the accuracy of CF prediction. In terms of the large error of the existing extinction angle (EA) calculation during the fault transient period, a method for CF prediction and mitigation is proposed. Variations in both DC current and overlap angle (OA) are considered in the proposed method to predict the EA rapidly. In addition, variations in critical EA and the effect of firing angle (FA) on both DC current and OA are considered in the proposed method to obtain the accurate FA order for the control system. The proposed method can achieve good performance in terms of CF mitigation and reduce reactive consumption at the inverter side when a fault occurs. Simulation results based on the PSCAD/EMTDC show that the proposed method predicts CF rapidly and exhibits good performance in terms of CF mitigation.

Bionic Perception Method of Navel Orange Plucking Position Based on Fmincon and PD Angle Control

In this paper, a bionic perception method of navel orange plucking position based on Fmincon and Proportional Differential (PD) angle control is proposed to solve the problems of wind disturbance and green branches in dynamic unstructured environment. Different from these algorithms that limited to two-dimensional images, this method realizes picking position perception in three-dimensional. Meanwhile, the perception method and the picking robot control algorithm are achieved simultaneously. Firstly, an optimal solution model of the global target rotation angle of the control system based on Fmincon is established to solve the angle optimization problem of robot target approach motion. Secondly, a bionic perception system of plucking position based on PD angle control is constructed to solve specific perception problems. Finally, a joint simulation platform for picking robots based on Solidworks, Adams, and Simulink is given; the validity and accuracy of the algorithm were verified. The experimental results show that the picking accuracy rate is 95%, the angle error of each mechanism and the displacement error are less than 0.5 degrees and 10mm, respectively. The total time from the optimized angle calculation to the system's stability is only about 0.33s. This method is suitable for the rapid perception of plucking position and active angle control of picking robots under dynamic unstructured environment.

Nonlinear electrodynamics effects on the black hole shadow, deflection angle, quasinormal modes and greybody factors

In this paper, we discuss the effects of nonlinear electrodynamics (NED) on non-rotating black holes, parametrized by the field coupling parameter β and magnetic charge parameter P in detail. Particularly, we survey a large range of observables and physical properties of the magnetically charged black hole, including the thermodynamic properties, observational appearance, quasinormal modes and absorption cross sections. Initially, we show that the NED black hole is always surrounded by an event horizon and any magnetic charge is permissible. We then show that the black hole gets colder with increasing charge. Investigating the heat capacity, we see that the black hole is thermally stable between points of phase transition. Introducing a generalized uncertainty principle (GUP) with a quantum gravity parameter λ extends the range of the stable region, but the effect on temperature is negligible. Then we compute the deflection angle at the weak field limit, by the Gauss-Bonnet theorem and the geodesic equation, and find that even at the first order, the magnetic charge has a contribution due to the “field mass” term. Small changes of the charge contributes greatly to the paths of null geodesics due to the P 2 dependence of the horizon radius. Using a ray-tracing code, we simulate the observational appearance of a NED black hole under different emission profiles, thin disk and spherical accretion. We find that the parameter P has a very strong effect on the observed shadow radius, in agreement with the deflection angle calculations. We finally consider quasinormal modes under massless scalar perturbations of the black hole and the greybody factor. We find that the charge introduces a slight difference in the fundamental frequency of the emitted waveform. We find that the greybody factor of the NED black hole is strongly steepened by the introduction of increasing charge. To present observational constrains, we show that the magnetic charge of the M87* black hole is between 0 ≤ P ≤ 0.024 in units of M, in agreement with the idea that real astrophysical black holes are mostly neutral. We also find that LIGO/VIRGO and LISA could detect NED black hole perturbations from BHs with masses between 5 M ☉ and 8.0 · 108 M ☉. We finally show that for black holes with masses detected with LIGO so far, charged NED black holes would deviate from Schwarzschild by 5∼10 Hz in their fundamental frequencies.

Design of double axis solar automatic light tracing device based on cloud platform

Solar energy is a widely distributed and inexhaustible "green" renewable new energy, which is one of the best solutions to the energy crisis in the world. However, the conversion efficiency of photovoltaic cells in large-scale solar applications is not high, and the cost is very high. Therefore, in order to increase the power generation capacity and efficiency of solar power generation, automatic tracking power generation devices should be used to replace fixed solar photovoltaic panels and other solar equipment. This design proposes a two axis solar tracking system based on the Internet of Things cloud platform. This system uses the sun viewing motion tracking method to drive photovoltaic panels in horizontal and vertical directions to track the sun. The preset tracking angle of the system is based on the sun azimuth angle and altitude angle operation rules calculated and collected by the sun angle calculation software, and combined with weather data to find the best angle for real-time tracking. This design will elaborate the design process from the aspects of system overall scheme design, hardware circuit design and host computer software development.

In Ukrainian

By the method of density functional theory (B3LYP, 6-31G **) three types of displacements are calculated, namely oscillations as a whole, rotation and diffusion of dimers &gt; Ge = Ge &lt;, &gt; Ge = Si &lt; and &gt; Si = Si &lt;, which are formed on the crystalline surface of Si (001) (4×2) during the deposition of germanium atoms under conditions of molecular beam epitaxy. Calculations of angles of buckling of addimers are carried out. It is shown that when the addimers as a whole oscillate around the equilibrium position, the energy barriers are quite low, the highest of them occurs for a mixed addimer &gt; Si = Ge &lt;. Pure adders &gt; Ge = Ge &lt; and &gt; Si = Si &lt; oscillate between two degenerate states with an energy barrier of 0.042 and 0.014 eV, respectively. The structures of the transition state and the intermediate when the addimer &gt; Ge = Ge &lt; is moved between adjacent cells in the approximation of the constant bond length &gt; Ge = Ge &lt; are obtained. As calculations have shown, all transformations of surface dimers occur with relatively small activation energies, the numerical values of which agree satisfactorily with the results of STM experiments available in the literature.

Analisis Algoritma Shi-Tomasi Dalam Pengujian Citra Senyum Pada Wajah Manusia

Problems in image processing to obtain the best smile are strongly influenced by the quality, background, position, and lighting, so it is very necessary to have an analysis by utilizing existing image processing algorithms to get a system that can make the best smile selection, then the Shi-Tomasi Algorithm is used. the algorithm that is commonly used to detect the corners of the smile region in facial images. The Shi-Tomasi angle calculation processes the image effectively from a target image in the edge detection ballistic test, then a corner point check is carried out on the estimation of translational parameters with a recreation test on the translational component to identify the cause of damage to the image, it is necessary to find the edge points to identify objects with remove noise in the image. The results of the test with the shi-Tomasi algorithm were used to detect a good smile from 20 samples of human facial images with each sample having 5 different smile images, with test data totaling 100 smile images, the success of the Shi-Tomasi Algorithm in detecting a good smile reached an accuracy value of 95% using the Confusion Matrix, Precision, Recall and Accuracy Methods.

Preoperative calculation of angles of vision and working area in laparoscopic surgery to treat a giant hiatal hernia.

BACKGROUNDGiant hiatal hernias still pose a major challenge to digestive surgeons, and their repair is sometimes a highly complex task. This is usually performed by laparoscopy, while the role of the thoracoscopic approach has yet to be clearly defined. AIMTo preoperatively detect patients with a giant hiatal hernia in whom it would not be safe to perform laparoscopic surgery and who, therefore, would be candidates for a thoracoscopic approach.METHODSIn the present study, using imaging test we preoperatively simulate the field of vision of the camera and the working area (instrumental access) that can be obtained in each patient when the laparoscopic approach is used.RESULTSFrom data obtained, we can calculate the access angles that will be obtained in a preoperative computerised axial tomography coronal section, according to the location of the trocar. We also provide the formula for performing the angle calculations If the trocars are placed in loss common situations, thus enabling us to determine the visibility and manoeuvrability for any position of the trocars.CONCLUSIONThe working area determines the cases in which we can operate safely and those in which certain areas of the hernia cannot be accessed, which is when the thoracoscopic approach would be safer.

Classification of multi-stage voltage sags and calculation of phase angle jump based on Clarke components ellipse

Multi-stage voltage sag is one of the problems in the power system that requires classification and separation of stages to recognize this phenomenon. An algorithm for classification of multi-stage voltage sags based on the ellipse drawn by Clarke's transformation components is presented in this paper. The proposed algorithm has the ability to detect if the voltage sag is single-stage or multi-stage, and separates the various stages of multi-stage voltage sag using the point-on-wave of initiation and recovery parameters that is the novelty of this paper. Also a new method for calculation the phase angle jump by considering the zero Clarke component in drawing an ellipse is presented. The proposed method has a better accuracy than the previous method, which did not consider the zero component of the Clarke's transform. For validation, the method is tested with real data provided by the Department of Energy and the Electric Power Research Institute and compared with the previous method. A 12-bus distribution network has also been used to evaluate the performance of the multi-stage voltage sags classification algorithm accurately. This 33 kV network has distributed generation sources and various types of multi-stage voltage sags have been created in this network that show the efficiency of the algorithm. The results show that the proposed algorithm is able to classify any type of multi-stage voltage sag.