Angular Parameters Research Articles

Craniofacial changes from 13 to 62 years of age.

SummaryBackgroundIn long-term studies of orthodontic, orthognathic, and prosthodontic treatments, control subjects are needed for comparison.ObjectivesTo study the craniofacial (skeletal, soft tissue, and dental) changes that occur in untreated subjects with normal occlusion between 13 and 62 years of age.Materials/MethodsThirty subjects with a Class I normal occlusion and harmonious facial profile were studied. X-ray examinations were performed at 13 (T1), 16 (T2), 31 (T3), and 62 (T4) years of age, and data were obtained from cephalograms. In total, 53 angular and linear parameters were measured using superimposition-based and conventional cephalometric methods to describe the craniofacial changes.ResultsThe jaws showed significant anterior growth from T1 to T2, and significant retrognathism from T3 to T4. The anterior face height and jaw dimensions increased significantly until T3. Significant posterior rotation of the mandible and opening of the vertical jaw relation, in addition to significant retroclination of the incisors and straightening of the facial profile, were found from T3 to T4.LimitationsGiven the small sample size at T4, it was not possible to analyse the gender dimension.Conclusions/ImplicationsCraniofacial changes continue up to the sixth decade of life. These changes are consistent, albeit to a lesser extent, with the adolescent growth patterns for most of the studied parameters, with the exceptions of incisor inclination, sagittal jaw position, vertical jaw relation and inclination, and posterior face height.

Operative Treatment of Adolescent Hallux Valgus

The hallux valgus deformity in pediatric patients is a common pathology with no definitive criteria for surgical treatment. The purpose of this study is to present mid-term postoperative results after surgical treatment of this foot deformity. The study included 43 operated feet in 29 patients, with an average age of 14.31 years. Scarf osteotomy was performed in 23 patients, combined with an Akin osteotomy in 14 of the cases; Chevron osteotomy was performed in seven patients, five patients were treated with the mini tightrope technique, two with the Ludloff osteotomy, and six patients with lateral hemiepiphysiodesis of the first metatarsal. We evaluated the change in angular radiographic parameters and the American Orthopaedic Foot & Ankle Society scale for data analysis. The mean follow-up of the study was 48 ± 33.2 months. The mean preoperative hallux valgus angle showed an average improvement of 30.19° to 12.79° (p < 0.001). Loss of correction of the HVA angle of 20.46° was noted at the time of final follow up (p > 0.05). Favourable correction of the intermetatarsal angle was achieved with improvement of 11.44° preoperatively to 7.35° postoperatively. Significant progression was found for the American Orthopedic Foot & Ankle Society score from 57 points (42–85) before surgery to 80 points (54–100) after surgery. The recurrence rate 6 months after surgery is 30.95% (13 cases). Relapse of the deformity after Scarf osteotomy was observed in nine cases; after mini tight rope technique in three cases, and in one case after Chevron osteotomy. In conclusion we state that the most important factor influencing the outcomes of treatment and postoperative recurrence rate is skeletal maturity. Surgical treatment should be indicated after growth plate fusion. Conservative treatment via orthotic devices is recommended until that time.

Unraveling Structural Phase Transformation by Simultaneously Determining the Lattice Constants and Mismatch Angle in VO2/Al2O3 Epitaxial Thin Films

As a prototype of a strongly correlated electron system, bulk vanadium dioxide (VO2) exhibits a large and reversible metal–insulator transition (MIT) near 340 K, concomitantly accompanied by a monoclinic–rutile structural phase transformation (SPT). In this study, we systematically investigated the SPT across the MIT in a (010)-VO2/(0001)-Al2O3 epitaxial thin film by simultaneously determining three lattice constants (a, b, and c) and the mismatch angle (Δβ) using high-resolution X-ray diffraction. The lattice constants a, b, and c were approximately 5.723, 4.521, and 5.393 Å, respectively, at room temperature, and the mismatch angle was approximately 122.02°. As the temperature increased, the lattice constants and mismatch angle did not change significantly until the temperature reached the MIT point. Then, a, b, and c suddenly increased to approximately 5.689 Å, 4.538 Å, and 5.411 Å, respectively, and retained this value up to nearly 90°C. However, the mismatch angle first slightly increased and then sharply decreased to 122.00°. Additionally, the lattice constants and mismatch angle were almost reproducible with decreasing temperature, except for hysteresis in the MIT region. These results verify that VO2 undergoes an MIT, simultaneously accompanied by SPT, in thicker films with small strain and weak substrate constraints, analogous to bulk VO2. This was further confirmed by in-situ varying-temperature Raman characterization. These findings provide insights into the SPT and reveal an angular parameter for judging the SPT in VO2 systems.

Comparing reliability between 3D imaging and 2D photography for external nasal anthropometry

This study investigates and compares the reliability and reproducibility of two facial anthropometric methods about external nasal angles, 3D imaging and conventional 2D photography. 2D photograph images and 3D images about external nose of 30 volunteers were taken using digital camera and Morpheus 3D scanner. To evaluate intra-rater reliability, each images were taken over two different days for each subject by the same researcher. To evaluate inter-rater reliability, another researcher took each images for each subject on the first day. The reliability of each method for measuring 4 external nasal angle is obtained using intraclass correlation coefficient (ICC) and compared. Inter-rater and intra-rater reliability of both 3D imaging and 2D photography had excellent agreement in all 4 nasal angles. In the nasofacial angular parameter, Inter-rater ICC, 2D photography was significantly higher than 3D imaging. Result of intra-rater ICC also showed both 3D imaging and 2D photography had good reliability in all 4 nasal angles. Similar to those of inter-rater ICC, nasofacial angular parameter showed statistically significant differences between 3D imaging and 2D photography. In terms of reliability, both 2D and 3D showed appropriate anthropometric results and considering its own advantage, each methods can be used complementarily.

Physical meaning of cutting edge length and limited applications of Specific Edge Load in low consistency pulp refining

AbstractSpecific edge load (SEL) is the extensively employed theory to characterize the refining results in low consistency pulp refining. But the physical meaning of its core parameter, cutting edge length (LC{L_{C}}), is not very clear, resulting in the limited applications ofSELin pulp refining. In this study, the physical meaning ofLC{L_{C}}was investigated in two aspects, total bar sliding length per cycle and total equivalent bar length, as well as the application of two refining intensities related to it,SELand the net tangential force per bar crossing zone (ftnet{f_{t}^{\mathrm{net}}}). After the comparison of the refining intensities and the experimental results, it was foundSELcalculated by theLC{L_{C}}with physical meanings can only properly characterize the results of the pulp refining conducted by straight bar plates with constant angular parameters. While, for the situations of varied angular parameters, theftnet{f_{t}^{\mathrm{net}}}and Modified Edge Load (MEL), calculated by the edge length expanded empirically by Meltzer, can also better characterize the refining process, either for the evolution of fiber length or the global refining effect (pulp Schopper Riegler). In addition, the application offtnet{f_{t}^{\mathrm{net}}}can be potentially expanded to other refiner plates to gain a better understanding and optimization of the pulp refining process.

Online Three-Axis Magnetometer Hard-Iron and Soft-Iron Bias and Angular Velocity Sensor Bias Estimation Using Angular Velocity Sensors for Improved Dynamic Heading Accuracy

This article addresses the problem of dynamic online estimation and compensation of hard-iron and soft-iron biases of three-axis magnetometers under dynamic motion in field robotics, utilizing only biased measurements from a three-axis magnetometer and a three-axis angular rate sensor. The proposed magnetometer and angular velocity bias estimator (MAVBE) utilizes a 15-state process model encoding the nonlinear process dynamics for the magnetometer signal subject to angular velocity excursions, while simultaneously estimating nine magnetometer bias parameters and three angular rate sensor bias parameters, within an extended Kalman filter framework. Bias parameter local observability is numerically evaluated. The bias-compensated signals, together with three-axis accelerometer signals, are utilized to estimate bias-compensated magnetic geodetic heading. Performance of the proposed MAVBE method is evaluated in comparison to the widely cited magnetometer-only TWOSTEP method in numerical simulations, laboratory experiments, and full-scale field trials of an instrumented autonomous underwater vehicle in the Chesapeake Bay, Maryland, USA. For the proposed MAVBE, (i) instrument attitude is not required to estimate biases, and the results show that (ii) the biases are locally observable, (iii) the bias estimates converge rapidly to true bias parameters, (iv) only modest instrument excitation is required for bias estimate convergence, and (v) compensation for magnetometer hard-iron and soft-iron biases dramatically improves dynamic heading estimation accuracy.

Angular-Based Mueller Matrix Polarimetry Parameters for Subwavelength Pore Size Differentiation

Mueller matrix polarimetry is exploited to find a potential polarization feature sensitive to subwavelength pore size variation in porous alumina samples. After careful analysis using standard machine learning methods, it is observed that existing Mueller matrix decomposition methods and parameters are insufficient to distinguish areas with different pore sizes. Thus, a new angular-based Mueller matrix polarimetry parameter capable of linearly separating areas with varying pore sizes is proposed. Such an angular-based parameter is novel because it is based on angular parameters, it utilizes multi-angle measurements, and it extracts physical information independent of existing decomposition methods or parameters. Hopefully this work should inspire future research on the angular parameters in Mueller matrix polarimetry and their relationships to microstructure information.

An efficient approach of centroid alignment for spaceflight vehicles considering parameter uncertainties

This paper deals with centroid alignment for the spaceflight vehicles that work on orbit under microgravity environment, due to the unavailability of centroid measurement on ground, which is based on the principle of mass–radius products in different configurations of static equilibrium. A physical prototype of articulated mechanism for centroid alignment, consisting of three sets of linear modules with moving mass mounted, was developed and experimentally validated. The variational method was adopted to derive the error model for accuracy and sensitivity analysis of the developed articulated mechanism with the consideration of parameter uncertainties, from which it is found that the centroid position of the whole system is much more sensitive to the angular parameter variations than the linear ones. With the developed error model, an iterative approach of centroid alignment to ensure the centroid offset to meet the requirement is proposed, regardless of whether the parameter variations can be ignored, and numerous simulations verify the efficiency of the proposed approach.

Influence of surface texture parameters of screw pump rotor on tribological properties of its friction pairs

PurposeThis study aims to solve the premature failure of the rubber stator due to wear, reduce the frictional resistance moment of the screw pump to solve the problem of a model of Daqing oilfield screw pump oil recovery system shutdown after the difficult start.Design/methodology/approachFor the first time, the rotor surface of a screw pump was treated with dot-matrix texture to study the effect of dot matrix texture on the tribological performance of the stator-rotor friction subsets of screw pump. Reciprocating friction tests with different texture morphologies (S-shape, double tongue) and angular parameters (0°, 45° and 90°) were conducted at 10% of the texture area and pump silicone grease.FindingsWhen point texture was added to the surface of the rotor sample, the friction coefficient and wear quantity of the sample were lower than those of the surface without texture treatment, and the double tongue 0° combination showed the best tribological properties. At this time, the average coefficient of friction and wear is reduced by 22.8% and 62%, 28.6% and 64.8%.Originality/valueThe introduction of texture can effectively improve the tribological performance of progressive screw pumps, and this paper provides important theoretical and experimental support for the design of progressive screw pumps in practical applications.

Accommodation structures during kink band evolution; quantitative methods applied to Late Variscan deformation of Portugal

Kink bands are common in rocks with a strong planar mechanical anisotropy, being generally developed in polydeformed areas during the late stages of deformation, in brittle to brittle-ductile conditions. In the Late Variscan deformation events in the Iberian Massif, several kink band structures were developed in association to the NNE-SSW sinistral strike-slip faults, which are induced by the Laurentia and Gondwana E-W dextral collision on Carboniferous times. Within two metric-scale kink bands, several 2nd order structures are generated in response to internal shortening during layering rotation. The present paper describes the internal geometry and kinematics of these type III fixed hinges kinks bands, discussing their deformation mechanisms. In order to quantify the internal shortening within kink bands, a new graphical method, using simple angular parameters, is proposed. This graphical approach applied to the studied kink bands allows their internal shortening to be quantified; it ranges between 12 and 18%. The genesis of 2nd order structures within kink bands results from the accommodation of the internal layer distortion during kink bands progressive deformation and is controlled by two main deformation processes: layer parallel shortening and layer parallel slip.

Preliminary analysis of linear and angular kinetic parameters of the gait of individuals with cerebral palsy

Normal gait patterns allow the identification of the normal movement pattern, such as the gait of people with cerebral palsy. Paralympic classification systems aim to include the participation in sports of people with cerebral palsy, minimizing the impact of the injury on the result of the competition. In this context, this study aims to investigate, functionally, the linear and angular kinetic parameters of gait in individuals with cerebral palsy. 15 participants with cerebral palsy were classified into three groups according to the classification of the International Paralympic Committee: 1) T35- diplegic; 2) T36- athetoid ataxic; 3) T37- hemiplegic. For data acquisition, we used a motion capture system in 3 dimensions. The results showed significant differences between the three groups in some linear and angular gait variables, corroborating the qualitative classification process already used by the International Paralympics Committee. In addition, we identified the existence of people with different levels of cerebral palsy within a single functional class of International Paralympics Committee. We found significant differences in some linear and angular gait variables among the classes T35, T36 e T37, which suggest "subgroups" inside each category, and this would prevent a athlete from competing on equal terms with the other competitors.

Revisiting the Fundamental Nature of Metal-Ligand Bonding: An Impartial and Automated Fitting Procedure for Angular Overlap Model Parameters.

The properties and reactivities of transition metal complexes are often discussed in terms of Ligand Field Theory (LFT), and with ab initio LFT a direct connection to quantum chemical wavefunctions was recently established. The Angular Overlap Model (AOM) is a widely used, ligand‐specific parameterization scheme of the ligand field splitting that has, however, been restricted by the availability and resolution of experimental data. Using ab initio LFT, we present here a generalised, symmetry‐independent and automated fitting procedure for AOM parameters that is even applicable to formally underdetermined or experimentally inaccessible systems. This method allows quantitative evaluations of assumptions commonly made in AOM applications, for example, transferability or the relative magnitudes of AOM parameters, and the response of the ligand field to structural or electronic changes. A two‐dimensional spectrochemical series of tetrahedral halido metalates ([MIIX4]2−, M=Mn−Cu) served as a case study. A previously unknown linear relationship between the halide ligands’ chemical hardness and their AOM parameters was found. The impartial and automated procedure for identifying AOM parameters introduced here can be used to systematically improve our understanding of ligand–metal interactions in coordination complexes.

Cover Feature: Revisiting the Fundamental Nature of Metal‐Ligand Bonding: An Impartial and Automated Fitting Procedure for Angular Overlap Model Parameters (Chem. Eur. J. 9/2022)

Our work on ligand field theory—an automated fitting procedure for Angular Overlap Model (AOM) parameters—is reflected by Van Gogh's Field with Irises near Arles. We showcase the capabilities of this procedure with a two-dimensional spectrochemical series with the metals manganese, iron, cobalt, nickel and copper and the halides fluoride, chloride, bromide and iodide. The perspective in van Gogh's field resembles a correlation we found between the halide ligands’ AOM parameters and their chemical hardness. More information can be found in the Research Article by V. Krewald et al. (DOI: 10.1002/chem.202103775). Original image credit: Van Gogh Museum, Amsterdam (Vincent van Gogh Foundation).

The transition boundaries between interaction regimes of liquid droplets colliding in a gas

In this research, we use two different approaches to distinguishing the interaction regimes of liquid droplets in a gas environment. The first one distinguishes the following regimes: coalescence (parent droplets merge), bounce (parent droplets approach each other and then move away from each other), separation (impact produces two new droplets of a similar size as the initial ones), and disruption (two initial droplets break up into more than two fragments). The second approach distinguishes the following regimes: coalescence (merging of initial fragments), bounce (merging and consecutive splitting into two fragments of similar size as the initial ones), stretching separation (fragmentation due to the stretching of the merged droplet), and reflexive separation (fragmentation due to the tendency of each fragment to take spherical shape). Experimental results for different slurries, emulsions, solutions, and single-component compositions allowed us to distinguish transition boundaries of collision regimes using the Weber and Ohnesorge number, as well as angular and linear interaction parameters. Mathematical expressions are obtained for the boundaries, describing the variation ranges of droplet interaction parameters as well as their properties required for the consistent transition from one collision regime to another. The expressions are second order polynomials with droplet size ratio, Weber number, Ohnesorge number, and interaction parameters as variables. A database of empirical coefficients is obtained for general mathematical expressions that can be used to predict the transition boundaries of droplet collision regimes. Any of the two approaches to distinguishing the regimes is equally viable for this matter.

Constructing angular conical FeSiAl/SiO2 composites with corrosion resistance for ultra-broadband microwave absorption

Nowadays, the scholars have studied many microwave absorbing materials (MAM) to solve the increasingly serious electromagnetic wave pollution, however, most of MAM are difficult to achieve the ultra-broad band absorption. In this work, we explored the practical applications of the inexpensive FeSiAl (FSA) by using the efficient electromagnetic simulation software, the Computer Simulation Technology (CST). Specifically, FeSiAl/silicon dioxide (FSA/SiO2) microwave absorbers were successfully prepared by a simple stirring method. The obtained FSA/SiO2 samples achieved a reflection loss (RL) of − 46.6 dB at 9.71 GHz. In addition, a quadrilateral cone model was established by the CST, and the influence of angular cone parameters on absorption performance was investigated in detail through electromagnetic simulation. It is found that the model exhibited extraordinary absorption ability and the effective absorption bandwidth (EAB) reached 16.3 GHz covering 2–18 GHz when the height (H), thickness (t), length (L) were set as 1.9 cm, 0.2 cm, 1 cm, respectively. This work may solve the shortcoming of the narrow absorption band of the absorption powders.

Angular distribution parameters in two-photon double ionization of helium beyond the dipole approximation

We study nondipole effects in the two-photon double ionization of helium by solving the full-dimensional time-dependent Schr\"odinger equation (TDSE). The angular distributions of the photoelectrons in TDSE calculations are parametrized by several angular distribution parameters. The electron correlation effects are revealed and discussed by analyzing angular distribution parameters of the photoelectrons. Compared with the linearly polarized laser, the values of dipole angular parameters for circularly polarized laser pulses in the nonsequential double-ionization regime are closer to the pure dipole emission of the one-photon single ionization, which indicates a weaker electron correlation for circular pulses. For the nondipole angular parameters, in the sequential double-ionization regime, we find that the parameters show peak structures from the sequential ionization channel over the energy sharing between two electrons and these peak positions are slightly shifted by the electron correlation. In general, due to the nondipole effects, the angular distributions of photoelectrons are shifted towards the direction of laser propagation, due to the transfer of the photon linear momentum.

Non-dipole effects on angular distribution of photoelectrons in sequential two-photon double ionization of Ar atom and K<sup>+</sup> ion

Owing to the development of XUV and X ray of the free-electron lasers, the photoelectron angular distribution in the sequential two-photon double ionization has received increasing attention of theorists and experimentalists, because it provides the valuable information about the electronic structure of atom or molecule systems and allows the obtaining of additional information about mechanisms and pathways of the two-photon double ionization. In this paper, the expression of the sequential two-photon double ionization process of the photoelectron angular distributions, including the non-dipole effects, is obtained based on the multi-configuration Dirac-Fock method and the density matrix theory, and the corresponding calculation code is also developed. Based on the code, the sequential two-photon double ionization process of the 3p and 2p shells of Ar atom and K<sup>+</sup> ion are studied, in which, the dipole and the non-dipole parameters of photoelectron angular distribution are investigated systematically. It is found that the angular distributions of the first- and second-step electrons in sequential two-photon double ionization are similar and the two photoionization processes affect each other. Near the ionization threshold, the photoionization cross-sections and anisotropy parameters for the 3p shell and the 2p shell show a large difference. While away from the threshold, the cross-section and angular anisotropy parameters of the 3p and 2p shells show similar behaviors. At the position of Cooper minimum of the photoionization cross section, the contribution of the electric dipole is suppressed, and the non-dipole effect is obvious. The non-dipole effect leads to a forward-backward asymmetric distribution of photoelectrons relative to the direction of incident light. The results of this paper will be helpful in studying the nonlinear processes of photon and matter interaction in the XUV range.

Photonics-Based Near-Field Measurement and Far-Field Characterization for 300-GHz Band Antenna Testing

In this study, photonics-based near-field measurement and far-field characterization in a 300-GHz band are demonstrated using an electrooptic (EO) sensor with planar scanning. The field to be measured is up-converted to the optical domain (1550 nm) at the EO sensor and delivered to the measurement system with optical fiber. The typical phase drift of the system is 0.46° for the one-dimensional measurement time of 13 s, which is smaller than the standard deviation of the phase measurement of 1.2° for this time scale. The far-field patterns of a horn antenna calculated from the measured near-field distribution are compared with that measured with the direct far-field measurement system using a vector network analyzer. For the angular related parameters, the accuracy of the results obtained by our near-field measurement are comparable to that of those obtained by direct far-field measurements. The sidelobe level discrepancy (approximately 1 dB) between the results obtained based on our near-field measurement and those from the direct far-field measurements are attributed to the excess noise of the probe correction data. We believe that photonics-based near-field measurements with spherical EO probe scanning will pave the way for the characterization of high-gain antennas at the 300-GHz band.

LP-DSPE Algorithm for Angular Parameter Estimation of Coherently Distributed Sources

The distributed source parameter estimator (DSPE) is one of the well-known angular parameter estimation techniques for coherently distributed sources. However, the computational cost of DSPE is not attractive due to the two-dimensional spectrum peak search. To overcome this problem, this letter proposes a novel DSPE algorithm based on compressive sensing theory, named as LP-DSPE algorithm. In the proposed method, at first, the nominal direction of arrival (DOA) estimation can be transformed into a linear programming problem through sparse recovery theory, whose feasible solution set is further expanded to improve the estimation accuracy. Then the angular spread can be obtained via a one-dimensional peak search utilizing the estimated nominal DOA. Compared with the previous works, the proposed algorithm can offer more accurate parameter estimation performance with lower computational complexity, even if in large angular spread scenarios. Theoretical analysis and simulation results demonstrate the performance of the proposed approach.

КЛИНИКО-РЕНТГЕНОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА МОЛОТКООБРАЗНОЙ ДЕФОРМАЦИИ СРЕДНИХ ПАЛЬЦЕВ СТОПЫ, СОПРОВОЖДАЮЩЕЙСЯ ПЕРЕГРУЗОЧНОЙ МЕТАТАРЗАЛГИЕЙ

Aim of the study. To study clinical and radiological features of hammertoe deformity of the middle toes, accompanied by overload (primary) metatarsalgia. The results of clinical and radiological examination of hammertoe deformity of 227 toes on 127 feet in 103 patients (96 women and 7 men) aged 31 to 79 years were studied. During clinical examination, the degree of transverse flatfoot and the variant of the 2 nd , the 3 rd , and the 4 th hammertoe deformity were determined, the passive range of motion in the metatarsophalangeal (MTP) joints was measured, the Visual Analogue Scale (VAS) for pain and the American Orthopаedic Foot and Ankle Society Lesser Toe Scale (AOFAS-II-V) were used. X-ray evaluation determined the angular parameters of the forefoot and evaluated the ratio of the lengths of the metatarsals. The analysis showed that the deformity of the 2 nd toe was noted in 54.62% of cases, the 3 rd – in 32.16%, and the 4 th – in 13.22% of cases. At the same time, the extensor variant of hammertoe deformity was observed in 29.9% of cases, the flexion variant – in 31.5%, and the extensor-flexion variant – in 38.6% of cases. X-ray showed a significant increase in the median values of the valgus angles of the 1 st , the 2 nd , the 3 rd , and the 4 th toes, as well as a significant excess of the length of the 2 nd metatarsal over the 1 st one. The median value of VAS reached 6 points, and the median AOFAS-II-V was only 35 points, while the state of the feet in 80.31% of cases was assessed as unsatisfactory. Thus, the deformity of the middle toes, complicated by overload metatarsalgia, is characterized by the prevalence of the most severe extensor-flexion variant of the hammertoe deformity, accompanied by an excessive length of the 2 nd and the 3 rd metatarsals, which leads to widespread corns on the sole and severe pain in the forefoot.