Calculation Of Angle Research Articles

The anisotropic adsorption of potassium cetyl phosphate on molybdenite surface and its implication for improving the flotation of molybdenite fines

The flotation of molybdenite fines is a challenging task during mineral processing worldwide. In this work, potassium cetyl phosphate (PCP) was explored as a novel collector to enhance the flotation of molybdenite fines. The flotation performances were assessed by micro-flotation tests. The adsorption mechanisms were uncovered through Zeta potential, Fourier Transform Infrared Spectrometer (FTIR), X-ray Photoelectron Spectroscopy (XPS), atomic force microscopy (AFM), Tafel curves, cyclic voltammetry, contact angle and density functional theory (DFT) calculations. The flotation tests demonstrated that PCP could efficiently collect molybdenite fines. Zeta potential and contact angle results suggested that the adsorption of PCP significantly improved the hydrophobicity of molybdenite surfaces. AFM, Tafel curves and adsorption energy revealed that PCP had a preferential affinity to edges (Eads = -735.14 kJ/mol) than faces (Eads = 33.5 kJ/mol). FTIR, XPS, cyclic voltammetry and DFT analysis manifested that PCP chemisorbed on the edges via the hybridization of the O 2p orbital of P-O radical within phosphate groups with the Mo 4d orbital, forming two high ionicity bonds, which could replace kerosene to improve the flotation of molybdenite fines.

Molecular dynamics simulations of water-ethanol droplet on silicon surface

Abstract Molecular dynamics simulations are used to explore the wetting behavior of a water-ethanol droplet on the silicon surface. The effect of ethanol concentration on the wettability of a water-ethanol droplet on the silicon surface was analysed by calculation of contact angle. At 30% ethanol concentrations, the water contact angle was 50.7°, while at 50% ethanol concentrations, it was 36°. The results showed that the contact angle of a droplet on a silicon surface decreases with increasing ethanol concentrations. The formation of hydrogen bonds (HBs) between water-water molecules was 677 for the 30% ethanol system, while at 50% ethanol concentrations, it was 141. The number of hydrogen bonds between water molecules reduces as the ethanol concentrations rise. The HBs between water molecules and the silicon surface is seen to grow as the ethanol concentration rises. The overall potential energies of pure water, 7:3 water-ethanol, and 1:1 water-ethanol systems are −74.4, −96.16, and −158.59 kcal/mol, respectively. The contact angle and number density of water molecules on the surface of the silicon revealed that at different ethanol concentrations, more water molecules are distributed on the silicon surface.

Application of GBT theorem for Gravitational deflection of light by Compact Objects

One of the most renowned classical experiments that verifies the curved nature of space-time geometry is the bending of light. This phenomenon is extensively discussed in most textbooks on general relativity, with a clear and comprehensive explanation provided. In this study, we employ the material medium approach to determine the refractive index associated with the gravitational field of a compact object with a quadrupole moment. Our research presents a method for calculating the gravitational deflection angle for compact objects by utilizing the refractive index and the GBT theorem for an isotropic metric. This method is particularly important because it allows for the calculation of the deflection angle for both light and relativistic particles. The material medium approach enables us to consider the compact object's gravitational field as a medium with a refractive index. By applying this approach, we establish a relationship between the refractive index and the quadrupole moment of the compact object. We then utilize this relationship to calculate the deflection angle of light and relativistic particles.

Optimized orientation of jointing system in free-form lattice space structures

The recent decades have witnessed the development of a new generation of space structures called free-form space structures. In this new family of space structures, due to the geometric nature of the structure, the orientation of the members varies substantially within the joints, meaning that the members need to be connected to the joints at different angles. The wide distribution of these angles throughout the structure will significantly affect the cost of fabrication. Therefore, accurate and automatic calculation of connection angles and their optimizations have always been of interest to researchers and manufacturers. This article has the following two main objectives. The first objective is to provide geometric calculations and obtain the connection angles of single-layer lattice space structures. The second, and more important objective is to review the existing methods and to develop a geometrical method for their optimization, referred to as the “node orientation optimization” method throughout this article. Using the mentioned method, a series of optimizations are carried out in a number of free-form lattice space structures and the results are studied.

Test-retest reliability of a novel method for trunk position sense measurement in older adults with and without hyperkyphosis

IntroductionAlthough the importance of trunk position sense as a clinical outcome measure related to spinal alignment has been established, there is no study evaluating the reliability of measurement techniques for trunk position sense in older adults. Hyperkyphosis is most prevalent in this population and is associated with adverse consequences. ObjectiveThis study aimed to investigate the test-retest reliability of a measurement technique consisting of photogrammetry and angle calculation in older adults with and without hyperkyphosis. MethodsFifty-three older adults completed the tests. Participants actively reproduced a trunk neutral position (TNP) from both a trunk extended position and a trunk flexed position. Absolute error (AE) and variable error (VE) indices were calculated to quantify position sense acuity. Intraclass Correlation Coefficient was used to estimate relative reliability. Absolute reliability was assessed by calculating Standard Error of the Measurements (SEM) and Minimal Detectable Change (MDC). ResultsThe digital photogrammetry showed excellent reliability for horizontal and global components of AE in both hyperkyphosis and control groups while reproducing the TNP from trunk flexion. Also, there was good reliability for AE and VE in the hyperkyphosis group when moving to the TNP from the trunk extension. The MDC values for AE ranged from 0.32 to 0.44 while reproducing the TNP from trunk flexion. The MDC values for AE ranged up to 0.96 when reproducing the TNP from trunk extension. ConclusionThis study suggests that digital photogrammetry is a reliable method with clinical applicability, which allows the detection of changes after clinical interventions.

A Proposed Controller for an Autonomous Vehicles Embedded System

Many research have observable development in the automated vehicle driving field during the last few decades. This research proposed a simple optimum Intelligent PID (SO PID) controller to simplify the automated vehicle motion control. Control of an autonomous vehicle’s steering routines plays an essential key role. Several steering control procedures are proposed that improve automated vehicle performance. The design of secure embedded control systems must overcome the difficulties associated with designing both computing and control systems. Also, this research introduces a model of the autonomous car prototype controlled via an Arduino microcontroller board and the GPS Module to receive the car coordinates. The car moves safely, and autonomously consequently avoiding the risk of human faults. Several algorithms such as angle and distance calculations to the waypoint and obstacle detection are combined to control the car movement.

Bolt Loosening Detection Using Key-Point Detection Enhanced by Synthetic Datasets

Machine vision based on deep learning is gaining more and more applications in structural health monitoring (SHM) due to the rich information that can be achieved in the images. Bolts are widely used in the connection of steel structures, and their loosening can compromise the safety of steel structures and lead to serious accidents. Therefore, this paper proposes a method for the automatic detection of the bolt loosening angle based on the latest key point detection technology using machine vision and deep learning. First, we built a virtual laboratory in Unreal Engine5 that could automatically label and generate synthetic datasets, and the datasets with bolts were collected. Second, the datasets were trained using the YOLOv7-pose framework, and the resulting model was able to accurately detect key points of bolts in images obtained under different angles and lighting conditions. Third, a bolt loosening angle calculation method was proposed according to the detected key points and the position relationship between neighboring bolts. Our results demonstrate that the proposed method is effective at detecting the bolt loosening angle and that the use of synthetic datasets significantly improves the efficiency of datasets establishment while also improving the performance of model training.

Solar Panel Tracker System Using GPS Technology

This article provides a solution to the problem of not improving three-dimensional systems with light sensors in tracker systems for solar panels, due to the inefficiency of operation in cloudy weather, with an increase in precipitation and contamination of photodetectors. The paper shows the calculation of the position angle of the tracker system relative to the changing position of the sun. The GPS system is able to automatically determine the location of the solar panel (latitude, longitude), then the microcontroller with the developed program performs a mathematical calculation, and the system automatically adjusts the solar panel to the sun. Thus, the need to use a photo sensor is eliminated, since the system automatically determines the optimal angle between the sun and the solar panel.

Impact Analysis of Digital Delay on Power Factor and Compensation Strategy for Electric Traction PWM Rectifier

Due to fast dynamic response and simple implementation, the transient direct current control (TDCC) strategy is widely used for electric traction rectifiers in high-speed train drive applications. However, the inevitable digital delay may increase the steady-state error of the TDCC and consequently degrade the ac-side power factor (PF). To address this, a comprehensive effects analysis of digital delay on traction rectifier is first performed, in which the relationship between the digital delay and PF is revealed and quantified. Furthermore, a phase shift compensation scheme is proposed to improve the PF. In this scheme, the modulation signal is compensated by shifting a specified angle, where the calculation of phase shift angle only needs a few control parameters. Extensive experimental tests are carried out to verify the effectiveness of the proposed compensation method.

Corneoscleral junction angle in healthy eyes assessed objectively

PurposeTo introduce a fully objective method to measure corneoscleral junction (CSJ) angle and evaluate the CSJ angle in healthy eyes. MethodsCorneoscleral topography (Eye Surface Profiler, ESP) was acquired from the right eye of 105 healthy Caucasian subjects, ranging from 18 to 59 years old. From the raw anterior eye height data, the topographic limbus was automatically demarcated in 360 semi-meridians. Further, in limbal location, the CSJ angle was automatically calculated from corneoscleral height data using neighbouring auxiliary points for angle calculation. Additionally, CSJ angle was statistically analysed regionally. ResultsThe mean CSJ angle was 177.5 ± 1.1°. There is a mean difference of 7.7 ± 3.7° between the steepest (smallest) and flattest (largest) CSJ angle within the same eye. There exist statistically significant differences between temporal (178.2 ± 1.4°) and nasal (176.4 ± 1.1°) regions (paired t-test, p < 0.001), and between superior (178.1 ± 1.1°) and inferior (177.9 ± 1.1°) regions (p = 0.038). CSJ angle is correlated with limbus position (r = 0.43, p < 0.001). ConclusionCSJ angle is rotationally asymmetric. CSJ varies regionally, being the smallest (steepest) in the nasal region. Significant rough changes in CSJ angle were observed for some healthy individuals.

Degradation of Indigo Dye Using Quantum Mechanical Calculations

The semiempirical (PM3) and DFT quantum mechanical methods were used to investigate the theoretical degradation of Indigo dye. The chemical reactivity of the Indigo dye was evaluated by comparing the potential energy stability of the mean bonds. Seven transition states were suggested and studied to estimate the actually starting step of the degradation reaction. The bond length and bond angle calculations indicate that the best active site in the Indigo dye molecule is at C10=C11. The most possible transition states are examined for all suggested paths of Indigo dye degradation predicated on zero-point energy and imaginary frequency. The first starting step of the reaction mechanism is proposed. The change in enthalpy, Gibbs free energy and change in entropy of the overall reaction are equal to -548268.223 kcal/mol, 30831.951 kcal/mol and 48.552 cal/mol.deg, respectively. The activation energy is 46176.405 kcal/mol. The reaction rate is equal to .

Methodology positional controlling of communications aerial platform in FANET in the minds of influction of radio electronic countermeasures

FThe article considers the method of controlling the positioning of communication aerial platforms in the FANET network in the conditions of radio-electronic countermeasures to achieve the target function: increasing the accuracy of managing the navigation parameters (movement) of communication aerial platforms (reducing the deviation from the target trajectory). The work shows the process of controlling the parameters of FANET communication aerial platforms positioning in the process of deployment, operation, and control of the rotation process of the main node of the air communication subnet. The deviation of the navigation parameters of the communication aerial platforms was estimated using simulation modeling. The process of determining the coordinates of the communication aerial platforms based on the received signals (probes) on the main transmission channel has been formalized. The article shows the use of a backup channel based on LoRа, to maintain control in conditions of loss of GPS signals, which can become the basis for estimating the energy consumption of the communication aerial platforms network in the process of information exchange. The process of adaptive adjustment of the navigation parameters of the communication aerial platforms is proposed to be carried out using the Kalman filter. The scientific novelty of the method consists in the application of a scientifically methodical apparatus of trigonometric transformations of the channel matrix and calculation of azimuthal and elevation angles for additional correction of navigation parameters by positioning the communication aerial platforms relative to the mobile base station. This approach allows you to achieve optimization of the target functions of the positioning management process and ensure real-time decision-making. The results of simulation modeling confirm the possibility of providing a smaller deviation of navigation parameters up to 30 m compared to the known solution using the PSO algorithm 340–400 m in height.

Mathematical model of the UAV landing approach system on the example of the course-glide path system

A mathematical model of the landing approach system for an unmanned aerial vehicle (UAV) on the example of a course-glide path system (СGS) is presented. The proposed mathematical model includes an information model of the ground and airborne segments operation for the approach system. The mathematical model of the ground segment implements the calculation of the CGS radio signals power level at a given point in space — the position of the UAV. The mathematical model of the onboard segment implements the determination of the UAV getting into the radio beacon coverage area and the calculation of the UAV deviation angles from the glide path line. The UAV dynamics model is considered as a set of pre-obtained trajectory points. The carried out computational experiments showed the fundamental adequacy of the mathematical model and its application possibility for checkout automatic control systems for aircraft-type UAVs during landing approach. Keywords UAV, landing approach system, course-glide path system, localizer, glide path radio beacon, marker beacon, mathematical model, UAV landing

Combining mathematical model for HRV mapping and machine learning to predict sudden cardiac death

Sudden cardiac death, a prominent cause of mortality, often occurs within a narrow time window of less than an hour. This study introduces a novel methodology with the aim of early prediction of sudden cardiac death. The proposed approach involves the extraction of diverse features from the ECG signal, including the calculation of angles between two vectors, the computation of triangle areas formed by consecutive points, the determination of the shortest distance to a 450 line, and their combinations. Additionally, a thresholding technique is proposed to identify the risk period and predict the occurrence of sudden death. To assess the performance of the algorithm, data from the MIT-BH Holter database were utilized. The results obtained demonstrate that the angle feature achieves an average sensitivity of 93.75% with five false alarms, the area feature achieves an average sensitivity of 88.75% with nine false alarms, the shortest distance feature achieves an average sensitivity of 86.25% with 12 false alarms, and the combined feature achieves an average sensitivity of 96.25% with three false alarms. Remarkably, unlike existing methodologies in the literature, this method exhibits high accuracy in predicting the development of the risk of sudden cardiac death (SCD) even up to 30 min prior to onset. As a consequence, it plays a critical role in diagnosing patients' conditions and facilitating timely interventions. Moreover, the results confirm the feasibility of predicting cardiac arrest solely based on geometric features derived from variations in heart rate variability (HRV) dynamics.

Using Inertial Measurement Unit Sensor Single Axis Rotation Angles for Knee and Hip Flexion Angle Calculations During Gait.

Hip and knee flexion joint motions are frequently examined in clinical practice using camera based motion capture (CBMC) systems; however, these systems require elaborate setups and dedicated space. Inertial measurement unit (IMU) based systems avoid these disadvantages but require validation before widespread adoption. Moreover, it is important for clinical practice to determine the stability of these systems for prolonged evaluation periods. The purpose of this study was to assess the validity of a three-sensor inertial measurement unit system for calculating hip and knee flexion angles during gait by comparing with a gold standard CBMC system. Validity was also examined before and after a treadmill walking session. Twenty healthy participants were tested. Twenty seconds of gait at preferred walking speed were analyzed before and after thirty-two minutes of treadmill walking using previously validated CBMC methods and with a custom IMU model. Measurement validity for the IMU system was evaluated using Bland & Altman 95 percent limits of agreement, linear regression, mean absolute error and root mean square error. The effects of a measurement zeroing calibration strategy were also investigated. Strong measurement agreement was observed for both hip and knee flexion angles, although overall agreement for the hip exceeded that for the knee. Linear regressions between the datasets for each participant illustrated strong (> 0.94) relationships between IMU and CBMC measurements. More significant changes between timepoints were observed for the knee than for the hip. Error values were generally reduced when zeroing calibration was implemented. The IMU system presented in this study is a convenient and accessible technique to measure joint angles. The protocol described in the current study can be easily applied in the clinical setting for evaluation of clinical populations. Additional development work on sensor placement and calibration methods may further increase the accuracy of such methods. Clinical translation statement: The IMU system presented in this study is a convenient and accessible technique to measure joint angles. Additional developmentwork on sensor placement and calibration methods may further increase the accuracy of such methods.

Instantaneous Angular Speed Extraction Based on Nonuniform Local Polynomial Differentiator for the Stiffness Identification of the Robot Joint

In the identification of industrial robot joint system, in order to obtain the ideal frequency response of the system, additional excitation needs to be applied. The addition of excitation signals, such as chirp signals and pseudorandom binary signals, will make the instantaneous angular speed (IAS) obtained by the motor encoder present nonstationary characteristics. In order to solve this problem, this article proposes a method for system identification by IAS extraction under nonstationary conditions. Interferences, such as electrical perturbation, quantization error, and background noise, generally reduce the accuracy of extracted IAS. First, the influence of electrical perturbation on the accuracy of angle calculation is eliminated by utilizing the characteristics of the two-phase encoder signals. Second, considering the time-varying characteristics of the rotational speed in the identification process, a nonuniform local polynomial differentiator (NULPD) is proposed to optimize the estimation of IAS and reduce the influence of background noise and sampling error based on local polynomial differentiator (LPD). The IAS estimation under the condition of variable speed is simulated to verify the performance of NULPD. According to the transmission characteristics of the robot joint system, a two-mass dynamic model is established, and the transfer function between the torque and motor speed is obtained. The torque is calculated from the three-phase current signals, and the rotational speed is obtained by the encoder signal. The frequency sweep experiment is carried out on the single-degree-of-freedom articulated arm test bench, where the stiffness and inertia of the system are identified within a certain error range by the proposed method.

CORDIC Processors: A Comparative Perspective of Radix-8, Radix-4, and Radix-2

Some data streaming applications make use of digital signal processing (DSP). The DSP algorithms include transcendental functions like trigonometry, inverse trigonometry, logarithms, exponentials, and other functions in addition to the basic arithmetic operations of multiplication and division. By modifying a few simple parameters, it is relatively simple to generate a large range of functions, including logarithmic, exponential, and trigonometric ones. Since the CPU needs around n rounds to process n bits of incoming data, the CORDIC radix-2 causes a substantial amount of latency. Therefore, radix-4 (which is radix-4 plus one) and radix-8 (which is radix-8 plus one) may be used to reduce the amount of time needed for the calculation. As a result, the total iterations drop from n/2 to n/4. As simulated and synthesized, it was shown that the radix-8 design had a significantly higher power consumption, with greater throughput than the radix-2 and radix-4 Coordinate Rotational Digital Computer (CORDIC) designs with an additional area overhead. The new algorithm also reduces the amount of twiddle elements to a minimum while also simplifying the address generating process. A novel approach makes integrating FFT processors on single chips much easier. This approach is demonstrated to be notably efficient in procedures such as SVD or matrix triangularization, in which the calculation of the rotation angle is necessary.

Automated measurement of carotid angle with use of CT images

Carotid stenosis is an important etiological factor in the forming of ischemic stroke. The weight of stroke which is formed as a result of extracranial internal carotid artery stenosis or occlusion differs according to the location, size of interaction, collateral supply, and the mechanisms those cause interact. Therefore, it is important to measure the narrowness of the carotid with the calculation of the bifurcation angle. In this study, CT cross-sectional image sequences are used. The images are unsupervised classified, and the carotid veins are identified with the boundaries and centers of the clusters. Then, the angles are calculated with three center points of the veins from successive images. The center point of the calculation is from the vein which has the maximum area difference between one of the successive images. The results are evaluated using 5 samples with visual interpretation regarding the position and the correctness of the three successive images which have maximum area jump.

Planar Constraint Assisted LiDAR SLAM Algorithm Based on Manhattan World Assumption

Simultaneous localization and mapping (SLAM) technology based on light detection and ranging (LiDAR) sensors has been widely used in various environmental sensing tasks indoors and outdoors. However, it still lacks effective constraints in structured environments such as corridors and parking lots, and its accuracy needs improvement. Based on this, a planar constraint-assisted LiDAR SLAM algorithm based on the Manhattan World (MW) assumption is proposed in this paper. The algorithm extracts planes from the environment point cloud submap, classifies the planes according to the ground and vertical planes, and calculates the main direction angles of the ground and vertical plane, respectively, to construct constraints. To enhance the stability and robustness of the system, a two-step main direction angle calculation and update strategy are designed, and a hysteresis update is used to avoid the introduction of errors by unoptimized planes. This paper uses a backpack laser scanning system to collect experimental data in various scenes. These data are used to compare our method with three open-source LiDAR SLAM algorithms, that are currently more widely used and perform better. Qualitative and quantitative experiments are conducted to verify the effectiveness of our method. The experimental results show that the absolute accuracy of the point clouds obtained by our method is improved by 77.46% on average compared with the other three algorithms in the environment, conforming to the MW assumption, which verifies the effectiveness of the algorithm.

Implementation of Human Pose Estimation Using Angle Calculation Logic on The Elder of The Hands as A Fitness Repetition

Sport cannot be separated from everyday life. Sport is a hobby for every age group. Everyone needs exercise to keep the body healthy and fit. Many people are busy with their respective activities, so they need more time to exercise and go to the gym. Apart from having to adjust the time, People stuck at Home do not have free access to go the Gym during the global pandemic. This can be overcome by tracking people's movements virtually. Human Pose Estimation can track the movements being carried out by a person in time. Data collection in the form of optimal detection distance, Human Pose Estimation in calculating the number of fitness repetitions, and data from the application of Human Pose Estimation when someone does fitness sports. The optimal distance webcam detects Human Pose Estimation for fitness reps is three meters. Webcams successfully track and predict the movements made by a person. The program can calculate fitness reps based on the angle at the elbow. The key points on the human body are connected by utility lines to form the body’s skeleton. Application, The repetitions in this detection utilize the value of the elbow angle when the hand is straight and bent. If the tip is &gt;300, such as lifting dumbbells, then a stage up is counted as one rep. Meanwhile, when the angle forms &gt; 1700, a stage down and one repetition also count The use of Media pipe for detection results is accurate and effective.