Angle Measurement Method Research Articles

Influence of magnetic casting on the permeability and anti‐fouling properties of a novel iron oxide/alumina/polysulfone mixed matrix membrane

AbstractNovel mixed matrix membranes (MMMs) were fabricated using Fe3O4, and Al2O3nanoparticles (NPs) were added to the polysulfone (PSf) and N‐methylpyrrolidone (NMP) solution. The nanocomposite membranes were fabricated using the NIPS (non‐solvent induced phase separation) method. In order to create preferential permeation pathways for water across the MMMs, membrane formation is accomplished with an external magnetic field. Using magnetic casting cause the targeted placement of NPs in the best location and orientation. The performance of the prepared membranes was examined in terms of pure water flux and fouling parameters. Magnetic casting considerably increased pure water flux and decreased the total resistance of the optimum mixed matrix membrane, which contains 0.2% wt. of Fe3O4NPs to 1175 L/m2h and 13.4 * 1011(m−1), respectively. This is explained by the ordering of magnetic nanoparticles on the membrane sub‐layer cast under the magnetic field of 500 mT, which changed the sub‐layer structure. Less rough membrane surface of the mixed matrix membranes offered preferable anti‐fouling properties against fouling by BSA proteins. The characterization of fabricated membranes was carried out using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), energy dispersive X‐ray (EDX), and water contact angle measurement methods.

Autocollimation angle-measurement method with a large range based on spot deformation.

A novel hollow cylindrical cube-corner reflector (HCCCR) for the autocollimator (AC) is proposed. The angle measuring range of AC will be effectively increased by using the parallel propagation characteristics of the reflected light and the incident light in local area of this reflector. And the yaw and pitch angles of HCCCR will be measured through the morphological changes of the reflected beam. The experimental results show that the measuring range of the autocollimation angle measurement method is extended from ±30' to ±30°, and the dynamic measurement distance is 0.2∼5m, the measurement accuracy of pitch angle and yaw angle is better than 69" and 51", respectively.

Visual encoder-based angle measurement method in low-frequency angular vibration calibration.

Angular vibration calibration is required to determine the sensitivity of sensors such as dynamic inclinometers, gyroscopes, and angular accelerometers, which are used for angular motion measurement in engineering applications. Additionally, the calibration performance depends on the accuracy of the angle measurement by laser interferometry or a circular grating (CG) method that is commonly used in vibration calibration. However, these methods usually own a complex and high-cost system or limited frequency and amplitude ranges. In this study, a novel, to the best of our knowledge, angle measurement method that combines a special visual encoder and an accurate angular position detection method is investigated; the method requires only a simple and flexible telecentric vision measurement system. Comparison experiments with the CG method demonstrate that the investigated method has the maximum measurement deviation of 0.0014° and 0.0138° for static angle measurement in the small-angle range and continuous full circle, respectively. The relative deviation of the angular vibration measurement in the range of 0.1-8 Hz with amplitudes 0-100° is less than 0.173%. Additionally, the relative deviation of calibrated sensitivity of a gyroscope by the investigated and CG methods is less than 0.096%.

Metode Pengukuran Sudut Gonial antar Pola Vertikal Skeletal pada Sefalometri Lateral

Background: Gonial angle is one of the angles measured in vertical skeletal analysis using lateral cephalograms. Gonial angle is made of tangent line to the posterior border of mandibular ramus with mandibular plane. Definition of gonial angle depends on mandibular plane which generally consists of various methods according to Downs, Tweed, and Steiner. Purpose: To investigate the difference of gonial angles measurement methods among vertical skeletal patterns on lateral cephalograms. Methods: Observational analytic research was conducted on 21 lateral cephalograms of orthodontic patients who had come to one of orthodontic clinic in Solo in 2016-2021. The cephalograms were taken by the same operator using Vatech PaX-i3D™, then they were categorized into 3 vertical skeletal pattern groups. Reference points and tracings were submitted to supervising orthodontist via ZOOM twice daily in the morning and in the afternoon. The measured data was recorded in table and was analyzed with Statistical for Social Science (SPSS) program. Results: In each vertical skeletal pattern groups, there was no significant difference found among Downs’s, Tweed’s, and Steiner’s gonial angles. There was significant difference among gonial angles of hypodivergent, normodivergent, and hyperdivergent samples. Conclusion: There was no significant difference of three gonial angle measurement methods among three vertical skeletal patterns on lateral cephalograms.

METODE PENGUKURAN SUDUT GONIAL ANTAR POLA VERTIKAL SKELETAL PADA SEFALOMETRI LATERAL

Background: Gonial angle is one of the angles measured in vertical skeletal analysis using lateral cephalograms. Gonial angle is made of tangent line to the posterior border of mandibular ramus with mandibular plane. Definition of gonial angle depends on mandibular plane which generally consists of various methods according to Downs, Tweed, and Steiner. Purpose: To investigate the difference of gonial angles measurement methods among vertical skeletal patterns on lateral cephalograms. Methods: Observational analytic research was conducted on 21 lateral cephalograms of orthodontic patients who had come to one of orthodontic clinic in Solo in 2016-2021. The cephalograms were taken by the same operator using Vatech PaX-i3D™, then they were categorized into 3 vertical skeletal pattern groups. Reference points and tracings were submitted to supervising orthodontist via ZOOM twice daily in the morning and in the afternoon. The measured data was recorded in table and was analyzed with Statistical for Social Science (SPSS) program. Results: In each vertical skeletal pattern groups, there was no significant difference found among Downs’s, Tweed’s, and Steiner’s gonial angles. There was significant difference among gonial angles of hypodivergent, normodivergent, and hyperdivergent samples. Conclusion: There was no significant difference of three gonial angle measurement methods among three vertical skeletal patterns on lateral cephalograms.

Using the Axial Oblique View of Computed Tomography (CT) in Evaluating Femoral Anteversion: A Comparative Cadaveric Study.

Twenty-five cadaveric adult femora’s anteversion angles were measured to develop a highly efficient and reproducible femoral anteversion measurement method using computed tomography (CT). Digital photography captured the proximal femur’s two reference lines, head-to-neck (H-N) and head-to-greater trochanter (H-G). Six reference lines (A/B in transverse section; C, axial oblique section; D/E, conventional 3D reconstruction; and M, volumetric 3D reconstruction) from CT scans were used. The posterior condylar line was used as a distal femoral reference. As measured with the H-N and H-G lines, the anteversion means were 10.43° and 19.50°, respectively. Gross anteversion measured with the H-G line had less interobserver bias (ICC; H-N = 0.956, H-G = 0.982). The 2D transverse and volumetric 3D CT sections’ B/M lines were consistent with the H-N line (p: B = 0.925, M = 0.122) and the 2D axial oblique section’s C line was consistent with the H-G line (p < 0.1). The D/E lines differed significantly from the actual gross images (p < 0.05). Among several CT scan femoral anteversion measurement methods, the novel anteversion angle measurement method using CT scans’ axial oblique section was approximated with actual gross femoral anteversion angle from the femoral head to the greater trochanter.

Deep learning-based tool affects reproducibility of pes planus radiographic assessment

Angle measurement methods for measuring pes planus may lose consistency by errors between observers. If the feature points for angle measurement can be provided in advance with the algorithm developed through the deep learning method, it is thought that the error between the observers can be reduced. A total of 300 weightbearing lateral radiographs were used for the development of the deep learning-based algorithm, and a total of 95 radiographs were collected for the clinical validation test set. Meary angle (MA) and calcaneal pitch (CP) were selected as measurement methods and measured twice by three less-experienced physicians with the algorithm-based tool and twice without. The intra- and inter-observer agreements of MA and CP measures were assessed via intra-class correlation coefficient. In addition, verification of the improvement of measurement performance by the algorithm was performed. Interobserver agreements for MA and CP measurements with algorithm were more improved than without algorithm. As for agreement with reference standard, combining the results of all readers, both MA and CP with algorithm were greater than those without algorithm. The deep learning algorithm tool is expected to improve the reproducibility of radiographic measurements for pes planus, especially by improving inter-observer agreement.

Automatic Cobb angle measurement method based on vertebra segmentation by deep learning.

The accuracy of the Cobb measurement is essential for the diagnosis and treatment of scoliosis. Manual measurement is however influenced by the observer variability hence affecting progression evaluation. In this paper, we propose a fully automatic Cobb measurement method to address the accuracy issue of manual measurement. We improve the U-shaped network based on the multi-scale feature fusion to segment each vertebra. To enable multi-scale feature extraction, the convolution kernel of the U-shaped network is substituted by the Inception Block. To solve the problem of gradient disappearance caused by the widening of the network structure from the Inception Block, we propose using ResBlock. CBAM (Convolutional Block Attention Module) can help the network judges the importance of the feature map to modify learning weight. Also, to further enhance the accuracy of feature extraction, we add the CBAM to the U-shaped network bottleneck. Finally, based on the segmented vertebrae, the efficient automatic Cobb angle measurement method is proposed to estimate the Cobb angle. In the experiments, 75 spinal X-ray images are tested. We compare the proposed U-Shaped network with the state-of-the-art methods including DeepLabV3 + , FCN8S, SegNet, U-Net, U-Net + + , BASNet, and U2Net for vertebra segmentation. Our results show that compared to these methods, the Dice coefficient is improved by 32.03%, 33.58%, 12.42%, 5.65%, 4.55%, 4.42%, and 3.27%, respectively. The CMAE of the calculated Cobb measurement is 2.45°, which is lower than the average error of 5-7° of manual measurement. The experimental results indicate that the improved U-shaped network improves the accuracy of vertebra segmentation. The proposed efficient automatic Cobb measurement method can be used in clinics to reduce observer variability.

Application of artificial landmark in sonar detection

Sonar is an important means of underwater target detection. However, the existing sonar measurement method does not use a third-party object as a reference, which makes it difficult to measure underwater targets. In this paper, we propose an angle measurement method and a 3D mapping algorithm based on sonar images and artificial landmarks. By combining acoustic and visual methods, using the known size information of artificial landmarks as a reference, we can calculate the target information to realize the mapping between real space and sonar images. Before verifying the feasibility, we processed the sonar image, denoised it with a median filter, enhanced the landmark image with the Sauvola algorithm, and finally introduced two data fitting methods to extract the edge information of artificial landmarks, so as to help us find the key points more accurately. The experimental results show that the accuracy of our method can reach the millimeter level, and the error range is within 5%. The technology proposed in this paper realizes the shape correction and precise length measurement of underwater targets.

Precision roll angle measurement system based on autocollimation.

The traditional autocollimation method is widely used for small angle measurement due to its high precision and high resolution, but it cannot be used to measure the roll angle. To overcome this problem, a roll angle measurement method based on autocollimation is proposed in this paper. To achieve roll angle measurement, a transmission grating is selected to generate a pair of measurement beams, and a combined target is designed as the angle sensor. A roll angle with higher accuracy and resolution can be obtained by differential measurement, because the measurement error introduced by the beam angle drift of the light source can be effectively suppressed. A series of experiments is carried out to verify the performance of the proposed system. In the experiments, the resolution of the roll angle is better than 0.05 arcsec, and the accuracy of the system is 0.20 arcsec with a measurement range of 250 arcsec.

Rotation angle measurement method based on self-mixing interference of a fiber laser.

A rotation angle measurement method based on self-mixing interference (SMI) of a fiber laser is proposed. The rotation angle can be calculated indirectly by the displacement measured by SMI. In the experiment, a linear cavity fiber laser with simple structure and high flexibility is used as the optical source for measuring the deflection angle. To improve the measurement accuracy, the SMI signal is filtered by the variational mode decomposition (VMD) algorithm. The filtered SMI signal is normalized by Hilbert transform. The even-power algorithm is used to subdivide the interference fringes, so as to improve the measurement resolution. The experimental result shows that the measurement error of angular shift is less than 1% in the range of 10°.

Investigation of Structural and Thermal Properties of Graphene Oxide Reinforced Epoxy Nanocomposites

The nanocomposites thin film was prepared by adding exfoliated GO in epoxy-hardner solution in different weight ratio. We investigate the thermal and surface properties of epoxy-graphene oxide (GO) nanocomposites using differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and contact angle measurement method. AFM and contact angle results are supporting that graphene oxide provides the best reinforcement in epoxy. AFM is investigated the dispersion of GO and structural morphology of epoxy nanocomposites. The FTIR results show that exfoliated GO of two-dimensional (2D) shape favors the hardening process of the epoxy matrix, increasing its reaction rate by observing an epoxy stretching frequency at 907 cm−1. The GO modified with amino group of epoxy lead to the increase of crosslinking density. FTIR absorption peak in 1700–1500 cm−1 regions is due to amino group. This attributes the significant increase of glass transition temperature of epoxy/GO nanocomposites . The contact angle and surface roughness increases with increase in concentration of GO in epoxy shows roughness induced hydrophobic surface. The solid surface energy was calculated by contact angle favors the good dispersion of GO in epoxy matrix.

Bearings-only Tracking Based on Distributed Multisensor Pseudolinear Kalman Filter

For bearings-only tracking (BOT), there are mainly two problems of nonlinear filtering and poor range observability. In the paper, a new distributed multisensor pseudolinear Kalman filter (PLKF) algorithm is proposed. The sensors use an instrumental vector PLKF (IV-PLKF) to process the measurements of the target independently, which can tackle the bias arising from the correlation between the measurement vector and pseudolinear noise by the bias compensation PLKF (BC-PLKF). The IV-PLKF embeds the recursive instrumental vector estimation method into the BC-PLKF, uses it to construct the instrumental vector, and applies the method of selective angle measurement to modify the local target state estimation and covariance. In the fusion center, the target state can be estimated by using the multisensor optimal information fusion criterion. Then the Cramer-Rao lower bound (CRLB) of multisensor BOT is derived. Simulation results show the effectiveness of the algorithm.

The effect of the electrospinning setup on the surface energy of polycaprolactone nanofibre layers

The study addresses changes in the surface energy of polycaprolactone nanofibre layers due to the different spinning electrodes. The value of surface energy and the associated wettability is an important aspect of polymeric biomaterials that influence the quality of interaction with biological material. The study involved the production of nanofibre layers by means of both needle and needleless electrospinning. The surface energy of the produced layers was determined via the contact angle measurement method. The experiment revealed that the spinning electrode exerts a significant effect on the resulting surface energy and, thus, on the wetting of the nanofibre layers. It was discovered during the measurement process, that the fibre layers produced via the needle electrospinning method evinced a low surface energy and are non-wettable/hydrophobic. In contrast, needleless electrospinning fibre layers evince a high surface energy and are wettable/hydrophilic.

Preparation of nanofibrous materials activated with metal clusters for active and long-lasting air filters

Nanowire poly(vinylidene fluoride) (PVDF) polymer membranes activated with Ag and Zn nanoclusters were prepared using the electrospinning method. The structure of membranes was varied by using different polymer concentrations in N,N-dimethylacetamide, electric field strength, and concentration of AgNO3 and ZnCl2 in an electrospinning solution. Materials synthesised were analysed by nitrogen sorption and mercury intrusion porosimetry, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy, thermogravimetry, inductively coupled plasma mass spectroscopy, particle filtration efficiency, and pressure drop methods. The concentration of Ag and Zn nanoclusters in PVDF membranes was established and the influence on nanofibers activity has been discussed. The hydrophobicity of membranes was tested using the wetting (contact) angle measurement method. The human influenza A virus (IAV) A/WSN/1933 (H1N1) strain was used to evaluate the virucidal activity of filtration materials. The virucidal activity increased with Ag nanoclusters concentration in fibres. The most hydrophilic nanofibers with Zn nanoclusters showed very high and practically concentration independent virucidal activity that was two orders of magnitude higher compared to materials activated with Ag nanoclusters.

Semi-automatic software-based 3D-angular measurement for Weight-Bearing CT (WBCT) in the foot provides different angles than measurement by hand

BackgroundThe purpose of this study was to compare semi-automatic software-based angular measurement (SAM) with previously validated measurement by hand (MBH) regarding angle values and time spent for the investigator for Weight-Bearing CT (WBCT). MethodsIn this retrospective comparative study, five-hundred bilateral WBCT scans (PedCAT, Curvebeam, Warrington, PA, USA) were included in the study. Five angles (1st - 2nd intermetatarsal angle (IM), talo-metatarsal 1-angle (TMT) dorsoplantar and lateral projection, hindfoot angle, calcaneal pitch angle) were measured with MBH and SAM (Bonelogic Ortho Foot and Ankle, Version 1.0.0-R, Disior Ltd, Helsinki, Finland) on the right/left foot/ankle. The angles and time spent of MBH and SAM were compared (t-test, homoscesdatic). ResultsThe angles differed between MBH and SAM (mean values MBH/SAM; IM, 9.1/13.0; TMT dorsoplantar, −3.4/8.2; TMT lateral. −6.4/−1.1; hindfoot angle, 4.6/21.6; calcaneal pitch angle, 20.5/20.1; each p < 0.001 except the calcaneal pitch angle, p = 0.35). The time spent for MBH / SAM was 44.5 ± 12 s / 12 ± 0 s on average per angle (p < 0.001). ConclusionsSAM provided different angles as MBH (except calcaneal pitch angle) and can currently not be considered as validated angle measurement method (except calcaneal pitch angle). The investigator time spent is 73% lower for SAM (12 s per angle) than for MBH (44.5 s per angle). SAM might be an important step forward for 3D-angle measurement of WBCT when valid angles are provided.

A New Angle Measurement in Translabial Ultrasound as an Adjunct for the Diagnosis of Pelvic Organ Prolapse.

The aim of this study was to compare the data obtained by a pelvic organ prolapse quantification (POP-Q) examination with the translabial ultrasound (TLUS) quantification of prolapse, using a new method of angle measurement. We analyzed the TLUS and POP-Q exam findings of 452 patients with symptoms of POP. The POP-Q system was used for clinical staging. TLUS was performed both at rest, and during the Valsalva maneuver after proper preparation. A horizontal reference line was drawn through the inferior margin of the symphysis pubis and the levator plate connected to the rectal ampulla, and the difference was calculated between the rest and the Valsalva maneuver. The Spearman’s correlation coefficient of agreement between the TLUS and the clinical POP-Q staging was used for statistical analysis. There was a weak degree of correlation between the POP-Q findings for the Ap parameter and our new angle measurement (rho = 0.17, p < 0.001). Thus, POP staging in conjunction with TLUS with this new angle measurement shows better agreement for the diagnosis of POP than POP-Q staging alone.

Laser tracking attitude angle measurement method based on weighted least squares

Laser tracking attitude angle measurement method based on weighted least squares

Unmanned Aerial Vehicle Attitude Angle Measurement Method Based on Laser Projection and Vision

Unmanned Aerial Vehicle Attitude Angle Measurement Method Based on Laser Projection and Vision

Spray angle measurement method based on grayscale image differential gradient

雾场边界及雾化角作为雾场的重要特性参数，主要通过图像法进行测量。在图像处理过程中，一般是将灰度图转化为二值化图像，然后依次针对二值化图像进行处理和计算。由于雾场的多相流特性，得到的二值化阈值和图像与实际雾场是否一致缺少评判依据。提出根据喷雾的灰度图像直接处理，得到掩模板并作用于灰度图像，采用图像形态学和迭代方法，计算灰度图像的梯度值。通过得到梯度值最大时的灰度图像，计算雾场边界和雾化角。实验表明，该方法提供了一种雾场边界的数值判断依据，通过梯度最大值判断并提取雾场边界，从而通过程序自动实现雾场边界提取与雾化角拟合测量。