Three-dimensional Parameters Research Articles

Quantitative Analysis of Morphometric Changes in Feminization Rhinoplasty Utilizing a Standardized Forehead-Rhinoplasty Technique

Abstract Background Rhinoplasty is one of the most commonly performed facial gender-affirming surgeries (FGASs) for transgender females, but well-established morphometric parameters describing feminizing nasal changes do not exist. Objectives Describe the author's technique for feminization rhinoplasty, analyze the changes in 3-dimensional nasal anthropomorphic parameters, and describe patient-reported outcomes. Methods Three-dimensional photogrammetric evaluation was performed both preoperatively and postoperatively in transgender female patients who underwent FGAS. Measurements assessed included the nasofrontal angle, nasolabial angle, dorsal height, mid-dorsal width, alar width, nasal tip width, and tip projection. Patients were surveyed preoperatively and postoperatively using the FACE-Q Nose module. Paired t-tests were utilized to assess changes in postoperative measurements and FACE-Q Nose satisfaction scores. Results Twenty patients underwent FGAS during the study period. The average time between surgery and postoperative 3-dimensional images was 13.6 ± 6.8 months. The nasofrontal angle increased by 8.2° (148.0 ± 7.4° to 156.1 ± 6.7°, P < .001) and tip projection increased by 0.017 (0.58 ± 0.03 to 0.60 ± 0.04, P < .01). Dorsal height, mid-dorsal width, and tip width all decreased significantly (P < .05). There were significant improvements in patients’ “Satisfaction with Nose,” “Satisfaction with Facial Appearance Overall,” “Psychological Function,” and “Social Function” on FACE-Q. One revision rhinoplasty was performed, and no documented surgical complications were reported. Conclusions There were statistically significant changes in the nasofrontal angle, tip projection, dorsal height, mid-dorsal width, and tip width in patients receiving feminization rhinoplasty. These data may help surgeons with preoperative planning and intraoperative decision making. Level of Evidence: 4

Average values for real-time two and three-dimensional echocardiographic parameters of mitral and tricuspid valves in a healthy Iranian population.

The reliability and validity of echocardiography are critical issues. Day and age, defining normal cases necessitates expressing natural physiological differences, including ethnicity. We are persuaded to evaluate average values in mitral and tricuspid valves in the Iranian population because only a few studies have been conducted to obtain average measures in echocardiography. This six-month study was conducted in a tertiary center's echocardiography lab. This study included 87 healthy Iranian volunteers who had no health issues. The tricuspid and mitral valves were examined using three and two-dimensional echocardiography. The investigated indicators produced normal data. The cases were divided into six age groups with a 12-year age gap. The participants ranged in age from 18 to 90, with 35 males (40/2 %) and 52 females (59/8%). By comparing tricuspid and mitral valve indices, this study found a difference between men and women (P<0.05). Furthermore, a difference in MV3D1, MV2CH1, MVPLAX1, MV3D2, MV4CH1, MV2CH1, MV ALAX2, MV2CH2, MV TENTING AREA, MV AREA indices at the mitral valve, and SAX2 TV4CH1, TV4CH2, TVSAX1, TVRVIF2 indices at the tricuspid valve was observed in various age groups (P-value<0.05). Our findings confirmed that gender and age impacted echocardiographic parameters, with a trend of decreasing measurements after 65 years of age and the most significant dimensions obtained after 42 years of age.

Evaluation of pharyngeal airway volume three-dimensionally in various sagittal skeletal patterns - Systematic review.

To investigate the pharyngeal airway volume in different anteroposterior skeletal malocclusions. This study was prepared according to the Cochrane criteria for creating a systematic review and meta-analysis and confirms the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. This search was conducted to answer the patient/population, intervention, comparison and outcomes (PICO) question: To evaluate (outcome) and compare (comparison) whether there is a difference in airway volume in patients (participants) with different skeletal malocclusions diagnosed using 3D data (intervention).The first two authors extracted the data from the included studies and assessed the risk of bias in the individual studies using the Newcastle-Ottawa scale. Meta-analysis was done using STATA version 16, which compared various three-dimensional pharyngeal airway parameters in skeletal Class II and skeletal Class III malocclusions with that of skeletal class I malocclusion. Out of 370 articles from the initial search, 17 articles were included in the systematic review. Out of 17 studies, 12 eligible studies were included in the quantitative synthesis. The nasopharynx, oropharynx, hypopharynx, and total airway volume were increased in skeletal Class I malocclusion compared to that of skeletal Class II malocclusion and decreased in comparison to skeletal Class III malocclusion. The moderate quality of evidence indicates the total airway volume, oropharynx, and hypopharynx are largest in skeletal Class III compared to Class I and Class II skeletal malocclusion.

Development and validation of a clinical tool to semi-automatic measure three-dimensional TAR alignment on two-dimensional radiographs

BackgroundMalalignment is often postulated as an important reason for the high failure rate of total ankle replacements (TARs). The correlation between TAR malalignment and clinical outcome, however, is not fully understood. Improving and expanding radiographic TAR alignment measurements in the clinic might lead to a better insight into the correlation between malalignment and the clinical outcome. This study aims to develop and validate a tool to semi-automatic measure TAR alignment, and to improve alignment measurements on radiographs in the clinic.MethodsA tool to semi-automatically measure TAR alignment on anteroposterior and lateral radiographs was developed in MATLAB. Using the principle of edge contouring and the perpendicular relationship between the anteroposterior and lateral radiographs, the exact configuration of the TAR components can be found. Two observers validated the tool by measuring TAR alignment of ten patients using the tool. The Intraclass Coefficient (ICC) was calculated to assess the reliability of the developed method. The results obtained by the tool were compared to clinical results during radiographic follow-up in the past, and the accuracy of both methods was calculated using three-dimensional CT data.ResultsThe tool showed an accuracy of 76% compared to 71% for the method used during follow-up. ICC values were 0.94 (p < 0.01) and higher for both inter-and intra-observer reliability.ConclusionsThe tool presents a reproducible method to measure TAR alignment parameters. Three-dimensional alignment parameters are obtained from two-dimensional radiographs, and as the tool can be applied to most TAR designs, it offers a valuable addition in the clinic and for research purposes.

Shape, alignment, and mass distribution of baryonic and dark-matter halos in one EAGLE simulation

Context. Accurate knowledge of the morphology of halos and its evolution are key constraints on the galaxy formation model as well as a determinant parameter of the strong-lensing phenomenon. Large-scale cosmic simulations are a tailored tool used to obtain statistics on the shape and mass distributions of these halos according to redshift. Aims. Using the cosmological hydrodynamic simulation, the Evolution and Assembly of GaLaxies and their Environments (EAGLE), we aim to provide a comprehensive analysis of the evolution of the morphology of galaxy halos and of their mass distributions with a focus on the snapshot at redshift z = 0.5. Methods. We developed an iterative strategy involving a principal component analysis (PCA) to investigate the properties of the EAGLE halos and the differences in alignment between the various components. The semi-axes and orientation of the halos are estimated taking into account sub-halos in the simulation. The mass distributions of the dark-matter (DM), gas, and star halos are characterised by a half-mass radius, a concentration parameter and (projected) axis ratios. Results. We present statistics of the shape parameters of 336 540 halos from the EAGLE RefL0025N0376 simulation and describe their evolution from redshift z = 15 to z = 0. We measured the three-dimensional shape parameters for the DM, the gas, and the star components as well as for all particles. We also measured these parameters for two-dimensional projected distributions. At z = 0.5, the minor axis of gas aligns with the minor axis of DM for massive halos (M &gt; 1012 M⊙), but this alignment is poorer for less massive halos. The DM halos axis ratios b/a and c/a have median values of 0.82 ± 0.11 and 0.64 ± 0.12, respectively. The gas in halos that also contain stars has a more flattened shape, with b/a = 0.70 ± 0.19 and c/a = 0.38 ± 0.20. The sphericity of gas in halos w/ and w/o stars appears to be negatively correlated to the total mass, while the sphericity of DM is insensitive to it. The measured projected axis ratios, bp/ap, of star halos at z = 0.5 have a median value of 0.80 ± 0.07, which is in good agreement with ground-based and space-based measurements within 1σ. For DM halos, we measure a value of 0.85 ± 0.06. The evolution of the concentration as a function of redshift is fairly homogeneous for the various components, except for the starless gas halos, which appear much more concentrated for z &gt; 0.7.

Value of 3D ultrasound flow imaging combined with serum AFP, β-hCG, sFlt-1 and CK in the diagnosis of placenta accreta

PurposeTo analyze the diagnostic value of placenta three-dimensional (3D) energy blood flow parameters combined with maternal serum AFP, β-hCG, sFlt-1 and CK levels for PA.Methods30 pregnant women with PA and 30 pregnant women with normal placenta were randomly selected in the Affiliated Maternal and Child Health Hospital of Nantong University from January 2021 to December 2021. Thereafter, the 3D energy ultrasound was applied to detect the placenta VI, FI and VFI. Moreover, the diagnostic value of different parameters combined with serum AFP, β-hCG, sFlt-1 and CK levels for PA was analyzed.ResultsMultivariate analysis results indicated that, gravidity > 2 and with/without placenta previa were the independent risk factors for PA (P < 0.05). In PA group, the AFP, β-hCG, CK, placenta VI, FI and VFI values were higher than those in non-PA group, while sFlt-1 was apparently lower than that in non-PA group. With the increase in PA degree, the serum AFP, β-hCG and CK levels increased. Meanwhile, serum sFlt-1 level was negatively correlated with PA degree. Serum AFP, β-hCG, sFlt-1, CK and placenta VFI showed prediction potency for PA, and their combined detection attained the optimal diagnostic value for predicting PA. ROC curve analysis suggested that, serum AFP, β-hCG, sFlt-1, CK and 3D ultrasound VFI value had the greatest AUC values in predicting PA, which might provide reference for the clinical diagnosis and disease evaluation of PA. Conclusion Serum AFP, β-hCG, sFlt-1, CK and placental VFI can increase the consistency in the diagnosis of PA. Serum markers combined with 3D ultrasound blood flow imaging can improve the sensitivity and specificity of prenatal diagnosis of PA, which provides an important reference for clinical diagnosis and treatment.

Facilitating glaucoma diagnosis with intereye neuroretinal rim asymmetry analysis using spectral-domain optical coherence tomography.

To determine whether intereye asymmetry of a three-dimensional neuroretinal rim parameter, the minimum distance band, is useful in differentiating normal eyes from those with open-angle glaucoma. This is a cross-sectional study of 28 normal subjects and 33 glaucoma subjects. Subjects underwent spectral domain optical coherence tomography imaging of both eyes. From high-density raster scans of the optic nerve head, a custom-designed segmentation algorithm calculated mean minimum distance band neuroretinal rim thickness globally, for four quadrants, and for four sectors. Intereye minimum distance band thickness asymmetry was calculated as the absolute difference in minimum distance band thickness values between the right and left eyes. Increasing global minimum distance band thickness asymmetry was not associated with increasing age or increasing refractive error asymmetry. Glaucoma patients had thinner mean neuroretinal rim thickness values compared to normal patients (209.0 μm vs 306.0 μm [P < 0.001]). Glaucoma subjects had greater intereye thickness asymmetry compared to normal subjects for the global region (51.9 μm vs 17.6 μm [P < 0.001]) as well as for all quadrants and all sectors. For detecting glaucoma, a thickness asymmetry value >28.3 μm in the inferior quadrant yielded the greatest sum of sensitivity (87.9%) and specificity (75.0%). Globally, thickness asymmetry >30.7 μm yielded the greatest sum of sensitivity (66.7%) and specificity (89.3%). This study indicates that intereye neuroretinal rim minimum distance band asymmetry measurements, using high-density spectral domain optical coherence tomography volume scans, may be an objective and quantitative tool for assessing patients suspected of open-angle glaucoma.

The influence of fracture surface morphology on propped fracture conductivity in tight sandstone reservoir

The investigation on the influence of fracture morphology on conductivity mainly focuses on the research of non-propped fracture conductivity. Few studies, however, have addressed the relationship between fracture surface characteristics and propped fracture conductivity. In this paper, by defining the maximum volume capacity of the fracture surface (VMF), according to the size relationship between the filling volume of proppants and VMF, the distribution state of proppants in propped fractures are divided into four modes, which can reflect the distribution state of proppant particle at different positions of the same fracture or different proppant concentrations in the rough surface fractures. Taking rough-surface rock samples and smooth-surface rock samples from tight sandstone reservoirs as experimental materials, a series of propped fracture conductivity tests in four modes are designed, supplemented by a various of methods such as refined characterization of three-dimensional roughness parameters of fracture surface and evaluation of proppant breakage rate. The influence of fracture morphology on the conductivity of propped fractures is systematically studied. The results show that the influence of fracture morphology on the conductivity of propped fractures varies with the distribution modes, which is closely correlated with the filling state and volume proppant filled in fractures. The influence of fracture morphology on the fracture conductivity in different distribution modes is revealed. Especially under the condition of multi-layer proppants, a new damage mechanism of fracture conductivity caused by fracture surface morphology is proposed, which is defined the “Retention Effect” of proppant particles caused by fracture surface morphology. The damage degree of this effect is characterized by defining “Damage Index of Fracture Conductivity on Rough Surface” (RFCI), which can quantitatively and accurately describe the damage degree of propped fracture conductivity caused by fracture surface morphology. The research results of this paper are helpful to understand the effect of fracture surface morphology on the conductivity of propped fractures, and also help to establish a laboratory model of the conductivity of rough fractures.

Optimizing fused deposition modelling parameters based on the design for additive manufacturing to enhance product sustainability

Nowadays, designers and engineers rely on specific manufacturing guidelines to bring quality products to market with minimum time and error. Design for Additive Manufacturing (DfAM) is one of these guides adapted to Additive Manufacturing (AM) technologies used to increase the operational performance of components, minimise material waste and provide design flexibility. DfAM optimises three-dimensional (3D) printing parameters to maximise the potential of AM technologies. DfAM improves ecological performance and provides many advantages for the transition to a circular economy by providing resource efficiency and enabling the production of parts with reduced weight without changing their mechanical strength. The aim of this study is to investigate the impact of the infill density, infill pattern and layer thickness on the printing time, weight, Young’s modulus, compressive stress, surface roughness, tensile strength, CO2 emissions and amount of material used for the samples printed using Poly-lactic acid (PLA) in the Fused Deposition Modelling (FDM) method. PLA has been chosen because it is a natural and recyclable polymer derived entirely from plant sources. In the printing process, samples with different mechanical properties have been obtained by changing the infill density (25%, 50% and 75%), the infill pattern (gyroid, triangle and grid) and the layer thickness (100, 150 and 200 µm) parameters. The Design of Experiment (DoE) method is provided to find optimal combinations of the selected parameters. According to the results of the study, the effect of the layer thickness differs on each output. While the infill density is 75%, grid and triangle structures generally give the best results among the infill patterns; infill density of 25% varies according to the infill pattern. The gyroid and triangle patterns give optimum results for less layer thickness (e.g. 100 µm), while the grid should be preferred for higher layer thickness (e.g. 200 µm).

INTRAOPERATIVE NON-INVASIVE LEFT VENTRICULAR MYOCARDIAL WORK INDICES IN PATIENTS UNDERGOING ON-PUMP CORONARY ARTERY BYPASS SURGERY

<h3>Objective</h3> Non-invasive echocardiographic analysis of left ventricular (LV) myocardial work (MW) enables insights into cardiac mechanics, contractility, and efficacy beyond ejection fraction and global longitudinal strain. MW incorporates myocardial deformation and loading conditions into its analysis and correlates well with invasively measured myocardial work outside the operative setting. However, there are no reports on the use of this method by transesophageal echocardiography (TEE) in patients undergoing coronary artery bypass graft (CABG) surgery. Therefore, we aim to describe the intraoperative course of this novel assessment tool of ventricular function in these patients and compare it to conventional two- and three-dimensional echocardiographic parameters and strain analysis. <h3>Design and Method</h3> Twenty-five patients scheduled for isolated on-pump CABG surgery with preoperative preserved left and right ventricular function and a complication-free intraoperative course, were included into this prospective observational trial. TEE was performed intraoperatively after induction of anesthesia (T1), after termination of cardiopulmonary bypass (T2), and after sternal closure (T3) using General Electric Vivid E95 echocardiography machines and 6VT-D TEE probes. All measurements were performed under stable hemodynamic conditions, in sinus rhythm or atrial pacing and vasopressor support with Norepinephrine ≤ 0.1 µg/kg/min. EchoPAC v204 software (GE Vingmed Ultrasound AS, Norway) was used for analysis of 2D- and 3D LV ejection fraction (EF), LV global longitudinal strain (GLS), LV global work index (GWI), LV global constructive work (GCW), LV global wasted work (GWW) and LV global work efficiency (GWE). <h3>Results</h3> Myocardial work analysis was feasible in all patients. Although there was no significant difference in the values of 2D- and 3D-EF during the intraoperative interval, GLS deteriorated significantly after CABG compared to assessment after induction of anesthesia (T1 v T2, -13.3±3.0% v -11.6±3.1%; p=0.012). GWI declined significantly after surgery (T1 v T2, 1224±312mmHg% v 940±267mmHg%; p<0.001) as well as GCW (T1 v T2, 1460±312mmHg% v 1244±336 mmHg%; p=0.005). GWW increased after CABG (T1 v T2, 143mmHg% (IQR 99-183) v 251mmHg% (IQR 179-361); p<0.001) and GWE decreased (T1 v T2, 89% (IQR 85-92) v 80% (IQR 75-87); p<0.001). There was no significant change in the values of 2D- and 3D-EF, GLS, GWI, GCW, GWW and GWE before and after sternal closure (T2 v T3). <h3>Conclusions</h3> Intraoperative non-invasive echocardiographic assessed left ventricular myocardial work analysis appears feasible in this study. In our small sample with 25 CABG patients, strain and myocardial work analysis showed a deterioration of left ventricular function. In the short-term period after uncomplicated on-pump CABG, global and constructive myocardial work was decreased, while wasted work was increased, resulting in a less efficient left ventricle. None of these aspects was detected by two- and three-dimensional ejection fraction. Therefore, myocardial work analysis might be a more sensitive parameter in detecting myocardial dysfunction by TEE in the perioperative setting.

Correlational analysis of three-dimensional spinopelvic parameters with standing balance and gait characteristics in adolescent idiopathic scoliosis: A preliminary research on Lenke V.

Background: Adolescent idiopathic scoliosis (AIS), the most common spinal deformity, possibly develops due to imbalanced spinal loading following asymmetric development. Since altered loading patterns may affect standing balance and gait, we investigated whether a correlation exists between balance ability, gait pattern, and the three-dimensional radiographic spinopelvic parameters in AIS patients. Methods: A cross-sectional observational study was conducted with 34 AIS patients (aged 10-18years) and an equal number of healthy age and sex-matched teenagers (normal group). We obtained the spinopelvic three-dimensional parameters and balance parameters simultaneously through the EOS imaging system and gait and center of pressure (CoP) characteristics using a plantar pressure measurement mat. Besides determining the intergroup differences in balance and gait parameters, multiple linear regression analyses were performed to identify any correlation between the static plantar pressure and radiographic parameters. Results: Compared to the normal group, the CoPx is lower, the CoP path length and 90% confidence ellipse area were significantly higher in AIS patients (AIS: -13.7 ± 5.7mm, 147.4 ± 58.1mm, 150.5 ± 62.8mm2; normal: -7.0 ± 5.4mm, 78.8 ± 32.0mm, 92.1 ± 41.7mm2, respectively), correlated with apical vertebra translation, sagittal pelvic tilt, and pelvis axial rotation, respectively. Moreover, AIS patients had a shorter stance phase (61.35 ± 0.97s vs. 62.39 ± 1.09s), a longer swing phase (38.66 ± 0.97s vs. 37.62 ± 1.08s), and smaller maximum pressure peaks in the gait cycle, especially on the left foot, as compared to healthy subjects. Moreover, the CoP trajectory in AIS patients was different from the latter, and changes in the bipedal trend were not consistent. Conclusion: The standing balance and gait characteristics of AIS patients are different from those of healthy subjects, as reflected in their three-dimensional spinopelvic radiographic parameters. Trial registration: The study protocol was registered with the Chinese Clinical Trial Registry (Number ChCTR1800018310) and the Human Subject Committee of Guangzhou Sport University (Number: 2018LCLL003).

Influence of the Metal Surface Texture on the Possibility of Controlling the Phase Transition of Water Droplets in the Single-Phase Regime

We experimentally studied the influence of the texture of copper and steel surfaces on the possibility of controlling the phase transition of water droplets in the single-phase regime. The texture of metals was formed by polishing and grinding, which corresponded to the finishing treatment of heat transfer surfaces in cooling systems for energy-saturated equipment. The samples were studied by microscopy and profilometry. The texture was estimated by three-dimensional roughness parameters. It was found that, with a 2–2.5-fold increase in roughness, the wetting of copper deteriorates (the contact angle increases from 66° to 93°), whereas the wetting of steel improves (the contact angle decreases from 89° to 71°). It was experimentally proven that, among the two main factors that affect the spreading diameter (wetting and roughness), wetting is the most significant. A hypothesis was formulated regarding the reason for the increase in the contact angle of 7–10° and the drop in the decrease rate of the contact diameter during the transition from the pinning to the mixed stage of droplet evaporation. It was found that an increase in the surface area of 0.1% leads to an increase in the total droplet evaporation rate of 4–6.5%.

Experimental Study on Mechanical Properties and Stability Analysis of Structural Plane under Unloading Normal Stress

Excavation in rock induces the unloading of stress in excavation-disturbed zones and can cause the structural plane to reach shear failure due to the unloading of normal stress. Unloading normal stress tests of a regular sawtooth structural plane were conducted in this study to investigate the influence of the unloading velocities (v) and asperity angles (θ) on mechanical properties and the stability of the structural plane. The average value of normal displacement (Du1) and the shear displacement of unloading (Dsu) gradually increases with an increase in θ and Du1 accounts for 59.70%, 31.81%, and 18.60% of the height of a single asperity under different θ. However, Du2, Ds, and the unloading capacity (Δσn) gradually decreased. Moreover, Ds account for 24.52%, 11.61%, and 7.4% of the length of a single asperity, respectively. With an increase in θ and v, three-dimensional (3D) morphology parameters and normal deformation energy (Un) decreased gradually, indicating that the damage degree of the structural plane increases. The analysis of the evolution of the gap width of the structural plane at the initial point, unloading point, and instability point indicates that the greater the θ or the smaller the v, the lower would be the likelihood for the structural plane to be damaged. Concurrently, its instability is more sudden and the impact tendency is stronger.

Design and optimization of molten salt reactor monitoring system based on digital twin technology

Abstract The nuclear power industry is developing rapidly toward intelligence and scale, the digital twin was combined with the industrial interconnection technology to solve the key problems in the application of the digital twin, such as the three-dimensional model presentation, real-time data docking, and the improvement of intelligence degree. Based on the example of Thorium Molten Salt Reactor-Solid Fuel (TMSR-SF0). Firstly, the three-dimensional twin of nuclear power equipment is constructed and the real-time update of twin data is realized based on the Node-EPICS event driver and Websocket communication protocol; Then, the communication interface with MySQL database is developed to realize the storage and management of data; Finally, the PID control system of molten salt circuit pipeline is integrated with back propagation neural network algorithm, and the efficiency and precision of temperature control system are improved by self-modification of weight. The results show that this system has the functions of three-dimensional display, network communication, data storage, and parameter optimization, and the data update cycle is raised to 100 ms, which can provide a certain reference value for the digital transformation of the nuclear monitoring field.

Evaluation of Three-Dimensional Surface Roughness in Microgroove Based on Bidimensional Empirical Mode Decomposition.

Micromilling is an extremely important advanced manufacturing technology in the micromanufacturing industry. Compared with the traditional milling process, micromilling has stricter requirements on the surface roughness of the workpiece, and the roughness of the microcurved surface is not easy to measure. In order to more accurately characterize the curved surface morphology of the microgrooves obtained by micromilling, this paper proposes a method to extract the reference plane of the curved surface based on the bidimensional empirical mode decomposition algorithm and characterize the three-dimensional surface roughness of the curved surface. First, we synthesize the morphologies of the microgrooves by simulated non-Gaussian rough surfaces and models of textures. Second, the bidimensional empirical mode decomposition algorithm was used to extract the reference planes of the simulated microgrooves. Third, the three-dimensional roughness parameters suitable for the curved surfaces of microgrooves were selected to establish an evaluation system. The results show that the mean squared errors of the reference planes are below 1%, so bidimensional empirical mode decomposition can effectively extract reference planes, and the evaluation system of three-dimensional surface roughness proposed in this paper reflects morphological characteristics of the curved surfaces of microgrooves more thoroughly than that of two-dimensional surface roughness parameters.

The Effect of Arch Stiffness on the Foot-Ankle Temporal Kinematics during Gait Termination: A Statistical Nonparametric Mapping Study.

This study compares foot-ankle temporal kinematics characteristics during planned and unplanned gait termination (PGT and UGT) in subjects with different arch stiffnesses (ASs) based on the statistical nonparametric mapping (SnPM) method. By measuring three-dimensional arch morphological parameters under different loading conditions, 28 healthy male subjects were classified and participated in gait termination (GT) tests to collect metatarsophalangeal (MTP) and ankle-joint kinematics data. The two-way repeated-measures ANOVA using SnPM was employed to assess the impacts of AS on foot-ankle kinematics during PGT and UGT. Our results show that joint angles (MTP and ankle joints) were altered owing to AS and GT factors. The flexible arches hahadve periods of significantly greater MTP and ankle joint angles than those of stiff arches during the stance phase of GT, whereas subjects exhibited significantly smaller ankle and MTP joint angles during UGT. These results add additional insights into the morphological arch biomechanical function, and the comprehensive compensatory adjustment of lower-limb joints during gait stopping caused by unplanned stimulation.

Evaluating Cranial Growth in Japanese Infants Using a Three-dimensional Scanner: Relationship between Growth-related Parameters and Deformational Plagiocephaly.

In this study, we aimed to evaluate the longitudinal changes in the cranial shape of healthy Japanese infants using a three-dimensional scanner and construct a normal values database for the growth process. Preterm infants (gestational age < 37 weeks), infants with neonatal asphyxia (5-minute Apgar score of <7), and patients who started helmet therapy for deformational plagiocephaly were excluded from this study. The first scan was performed at approximately 1 month of age, followed by two scans conducted at 3 and 6 months of age. The parameters considered were as follows: cranial length, width, height, circumference, volume, cranial vault asymmetry index, and cephalic index. A cranial vault asymmetry index >5% was defined as deformational plagiocephaly. Changes in each parameter were examined using repeated-measures analysis of variance classified by sex and deformational plagiocephaly status. The rate of increase in each parameter was also examined. In total, 88 infants (45 boys and 43 girls) were included in this study. All growth-related parameters were noted to increase linearly with time. Sex differences were observed in all parameters except cranial length. Deformational plagiocephaly was found to have no effect on growth-related parameters. Cranial volume increased by 60% from 1 to 6 months of age. The growth almost uniformly influenced the rate of increase in volume in each coordinate axis direction. Overall, the mean trends in three-dimensional parameters in infants up to 6 months of age were obtained using a three-dimensional scanner. These trends could be used as a guide by medical professionals involved in cranioplasty.

Leader-follower scheme for unicycle-type mobile robots with mounted camera

This paper describes a formation control proposal for unicycle-type mobile robots under the leader-follower scheme with mounted camera. The control objective is determined directly in image space, hence this proposal corresponds with the Image-Based Visual Servoing (IBVS) alternative. Using the Lyapunov stability theory, two controllers are designed: one that depends partially on the parameters of the vision system and another one that is robust to the three-dimensional parameters of the features that are mapped to the image space (the image features). Finally, experiments on a soft real-time platform with satisfactory results are carried out to validate the proposed theory.

Metamodel-Interpreted Data Mining for Stability and Efficiency Enhancement of Multistage Axial-Flow Compressors

Abstract The tradeoff between higher efficiency and wider stability of performance map is still one of the bottlenecks to hamper the further research and development of advanced multistage axial-flow compressor. The recent rapid growth of computational resources and artificial intelligence has enabled data mining as one of the most effective and potential ways to gain a deep insight into the complex correlations between aerodynamic performance and three-dimensional geometry parameters. In the open literatures, however, few research works have been found on using the data mining that is independent of design optimization to extract priori design guidelines for multistage axial-flow compressor mainly due to the lack of proper data mining method focused on the interpretation of metamodel with full use of limited time-consuming computational fluid dynamics dataset. To tackle this issue, a metamodel-interpreted data mining framework is developed in which extreme gradient boosting (XGBoost) metamodel combined with Shapley additive explanation (SHAP) model are employed to locally interpret the feature importance of each sample in the computational fluid dynamics dataset and then extract the design guidelines in terms of the most influential geometry parameters and their beneficial variation directions. The developed method is applied to data mining of design guidelines for efficiency and stability enhancement of a front 3.5-stage transonic axial-flow compressor in ship-board gas turbine usage. The results show that the aerodynamic performance of the investigated multistage compressor is most sensitive to three-dimensional geometry parameters related to blade lean, blade twist, and variable stators. Specially, the variable stators mainly affect the stall margin at part speed. The blade lean mainly influences the adiabatic efficiency at design speed as well as the stall margin at both speeds, while the blade twist mainly influences the aerodynamic performance at design speed. New designs followed by the design guidelines are obtained and critical performance indicators related to the goals of the data mining task are verified. The stall margin at part speed is widened to 5.87% with adjustment of blade lean and twist and further to 23.31% with additional adjustment of variable stators. The peak adiabatic efficiency at design speed is improved by 0.06% in spite of extremely limited potential for efficiency enhancement of the original design. The present work is of scientific significance as well as industrial application value in the three-dimensional design optimization of advanced multistage axial-flow compressor at the affordable computational cost.

Mixture distribution model for three-dimensional geometric attributes of multiple discontinuity sets based on trace data of rock mass

The geometric attributes of discontinuities are critical to an accurate discrete fracture network (DFN) model of rock mass. It is difficult to estimate three-dimensional (3D) geometric parameters of multiple groups of discontinuities by observation data. The study proposes a mixture distribution model for the 3D geometric attributes of multiple discontinuity sets. The method of estimating the mixture distributions of 3D geometric attributes of all discontinuity sets from the two-dimensional (2D) trace data in a sampling window is established and modified, including discontinuity diameter distribution estimation, volume density estimation, orientation distribution estimation, and distribution mixing. Discontinuities are assumed to be thin disks uniformly distributed in space, and their roughness and aperture are ignored. Discontinuity diameter and orientation follow lognormal distribution and bivariate normal distribution, respectively. Orientation distributions defined on the definitional domain of the geological coordinate system are derived to represent the real frequency distributions of orientation measurements in 3D rock mass space. The mixture distribution model is verified by using Monte Carlo method to generate DFNs with different volume densities, and distribution parameters of orientation and diameter. The maximum error of volume density is <0.5 m−3. The estimated distributions of diameter and orientation are in good agreement with the true distributions, while there are limited symmetry estimation errors of the discontinuity sets with orientation samples covering both sides of the 0° or 180° polar axis. The model is applied to Sejilashan tunnel, and the result indicates that the surrounding rock of two excavation faces have a high probability to be rated as the V classification according to the engineering classification of rock mass in China, which is in good agreement with the reality according to the geological survey and field observation.