Plane Area Research Articles

Some Aspects on the Elastic Behavior of a Bimetal Considering the Sensitivity of the Thickness of the Layers

Abstract Bimetals are usual designed by use of analytical formulas based on the beams theory from the Strength of materials. The paper presents a FEA study of a bimetal beam with two layers: Invar and Copper. The sensitivity of the thickness of layers was considered for: equal layers thickness, thickness calculated with a formula recommended in classical literature for optimizing the deformation (based on the Young modulus of the components) and several intermediary thickness values. For the case of the equal layers thickness the results from FEA and analytical formulas are compared. For all the studied models stress and deformation components from the longitudinal symmetry plane area are presented by comparison. The CAD and FEA models were developed within the FreeCAD open-source package.

Semantic and sentiment trajectories of literary masterpieces

The paper deals with semantic and sentiment trajectories of literary masterpieces (we used corpora of 12 languages of various language families), composed of individual embeddings or n-grams. We ascertain that, for all languages, semantic and sentiment trajectories are markedly chaotic: positive largest Lyapunov exponents; ‘entropy-complexity’ pairs belonging to the ‘chaotic’ area of the respective plane; the distinctive ‘chaotic’ drop of the number of false nearest neighbours at a particular value of an embedding dimension. The Russian language turns out to be more ‘chaotic’ than, for example, the English one; we attribute this fact to the free order of words. The Esperanto language, for various ‘approaches’ to different Indo-European languages. The results do not corroborate its claim to be equidistant from all languages. However, it seems to be equidistant from all Indo-European languages. These characteristics are utilised in order to develop a method to compare styles of an original masterpiece and its translations (to automatically assess translation quality). It appears that machine translations are still worse than human ones, however, for example, the Facebook translation is comparable with them.

Pilot protection method of half-wavelength AC transmission lines based on random matrix theory

The fault characteristics of ultra-high voltage (UHV) half-wavelength (HWL) transmission lines exhibit significant differences from those of conventional transmission lines, which renders the conventional relay protection method unsuitable for ensuring the protection of HWL. To solve this problem, a pilot protection method of HWTL based on random matrix theory was proposed. Voltage and current fault components obtained at the protection installation on both sides of the line were used as the input of the random matrix to form the singular value equivalent matrix, and the eigenvalues of the random matrix at both ends were calculated. The faults inside and outside the area were determined according to the distribution of the eigenvalues in the circular plane area. The protection scheme avoids the data synchronization problem at both ends of the line. Real time digital simulation system (RTDS) simulation revealed that the proposed protection method can protect the full length of the line, is suitable for various fault types and fault conditions, and exhibits excellent resistance to transition resistance.

Effect of mouth breathing on upper airway structure in patients with obstructive sleep apnea

Objective:To compare the changes of morphology of pharynx in patients with obstructive sleep apnea hypopnea syndrome （OSAHS） and healthy individuals during oral or nasal breathing, and explore the relevant influencing factors. Methods:Twenty-nine adult patients with OSAHS and 20 non-snoring controls underwent MRI to obtain upper airway structural measurements while the subjects were awake and during mouth breathing with a nasal clip.The following were analyzed. ①The changes of upper airway structure of oral and nasal respiration in non-snoring control/OSAHS patients were observed; ②The differences and influencing factors of upper airway structure changes between OSAHS patients and controls were compared during breathing. Results:The control group consisted of 15 males and 5 females, with an apnea-hypopnea index （AHI）<5 events/h, while the OSAHS group comprised 26 males and 3 females with an AHI of 40.4±23.1 events/h and the mean lowest arterial oxygen saturation （LSaO2） was 79.5% ±10.0%. In the both groups, the vertical distance between the mandible and the posterior pharyngeal wall decreased （P<0.05）; The long axis of tongue body decreased （P<0.05）, and the contact area between tongue and palate decreased. There was no significant change in the total volume of the retropalatine（RP） and retroglossal（RG） airway in the control group （P>0.05）. However, the minimum cross-sectional area and volume of the RP airway in OSAHS decreased （P<0.001）. The lateral diameters of uvula plane in OSAHS decreased during mouth breathing, which was contrary to the trend in the control group （P=0.017）. The AHI of patients was positively correlated with the reduction of the volume of the RP airway during oral breathing （P=0.001）; The reduction of the distance between the mandible and the posterior pharyngeal wall was positively correlated with the length of the airway （P<0.001）. Conclusion:Mouth breathing leads to the shortening of the long axis of the tongue, the reduction of the contact area between the soft palate and the tongue, vertical distance between the mandible and the posterior pharyngeal wall, and the cross-sectional area of the epiglottis plane. These changes vary between OSAHS patients and controls. During mouth breathing, the diameters, areas and volumes of the RP area decreased, and were more significant in severe cases.

Effects of process parameters on the spreading morphology of disc surface and aluminium powder produced by centrifugal atomisation

ABSTRACT An apparatus was developed to study the effects of operating parameters on liquid spreading and particle size in centrifugal atomisation. Different areas of aluminium spreading on the surface of the rotary disc were observed, in which the diameter of the ‘Plane area’ showed a linear relationship with the rotational speed. The microscopic morphology of the aluminium powder samples was analysed by scanning electron microscopy (SEM). The variation of particle size distribution curve with rotational speed was explored, and the shape of the curve was changed from ‘Single-peak’ to ‘Double-peak’ when the rotating speed increased to a certain value. The effect of the fragmentation mode on the particle size distribution and median diameter was analysed. The variation of the median diameter of the powder with the rotating speed was obtained. The effect of different disc configurations on the particle size was obtained.

Design optimization of a TetraSpar-type floater and tower for the IEA Wind 15 MW reference wind turbine

We present an optimization study for the conceptual design of wind turbine floaters of the TetraSpar type. The optimization variables include all geometric dimensions of the floater, keel, mooring lines and tower design. A gradient based optimization method is applied to a mass proportional objective cost function. The objective function accounts for the different weight components of the floater, including secondary steel, the wind turbine tower, and the mooring system. A frequency domain response method is utilized, so that each design evaluation also takes into account the dynamic response for 12 wind speeds with associated wave conditions. Nineteen constraints are applied for static and dynamic response, natural frequencies, and fatigue at the bottom of the tower. Two reference designs are presented, namely one with a soft–stiff tower and one with a stiff–stiff tower. Due to the anti-phase coupling of the floater pitch and tower vibration, the soft–stiff tower needs a stronger floater stiffness in pitch. This design thus has a larger water plane area moment than the more compact stiff–stiff floater, which is found to be the least economical. A constraint analysis is next presented based on Lagrange multipliers and a relative cost index. We find that the strongest cost influence is exerted by the 3P tower frequency constraint for the stiff-stiff and soft-stiff designs. Finally, a third design variant with a free optimizable tower frequency is introduced. This design is found to be 11% cheaper than the soft–stiff design and highlights the potential cost savings of tower designs within the 3P region.

Crystallographic characterization of naturally occurring aragonite and calcite phase: Rietveld refinement

This research has comprehended the crystallographic characterization of two naturally occurring calcium carbonates phases e.g. aragonite and calcite in Pila globosa (P. globosa) and eggshells respectively. The tools employed to confirm the phases of aragonite and calcite were X-ray diffractoion (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy. Several important crystallographic parameters like crystallite size, lattice parameters, dislocation density, crystallinity index, microstrain, volume of the unit cell, relative intensity of a certain plane, preference growth, and specific surface area were taken into account while assessing the desired aragonite and calcite phases. A number of well-known models e.g. Straight-line model of the Scherrer model, the Monshi-Scherrer model, the Williamson-Hall model, the Sahadat-Scherrer model, and the three-peak model aided the estimation of crystallite size. In all the cases, the observed crystallite size of calcite was larger than that of aragonite. The percentage of calcite and aragonite in eggshell and P. globosa were assessed by Rietveld refinement method. Observed results revealed that 97.4% calcite and 2.6% aragonite phases are present in eggshell while in P. globosa these percentages exist inversely, i.e. 93.2% aragonite and 6.8% calcite phases.

PHANTOM AND CLINICAL STUDIES ON LOW-DOSE CT PROTOCOL FOR APPLICATOR RECONSTRUCTION IN THREE-DIMENSIONAL BRACHYTHERAPY USING SIZE-SPECIFIC DOSE ESTIMATES BASED ON WATER EQUIVALENT DIAMETER.

To verify the feasibility of low-dose computed tomography (CT) protocol for applicator reconstruction in three-dimensional brachytherapy among patients of different sizes, using size-specific dose estimate based on water equivalent diameter (SSDEdw) in phantom and clinical studies. Pre-scans of a female pelvic phantom were followed by reconstruction of each image set with iDose4 levels 3-5. Imaging data from 64 cervical cancer patients were divided into low, standard and high weight groups. Among two to five CT scans required for applicator reconstruction, the first scan was adopted by routine-dose CT protocol (tube voltage = 120 kV, tube current-exposure time product = 320 mA.s) and the remaining by low-dose CT protocol (tube voltage = 120 kV, tube current-exposure time product = 80 mA.s). The SSDEdw and image quality parameters were compared among the groups, and correlations between SSDEdw and body mass index, area of reference plane (AreaROI3) and mean CT value of reference plane (CTROI3) were analyzed. According to the phantom test results, we determined tube voltage to 120 kV and tube current-exposure time product to 80 mA.s as the low-dose protocol. Clinical study revealed no statistically significant differences in signal-to-noise ratio (SNR) and contrast-noise-ratio (CNR) between low-dose and routine-dose CT in Groups A and B; in Group C, these were significantly lower in the former. The SSDEdw was significantly lower under low-dose than routine-dose protocol in all groups, with strong negative correlation with BMI and AreaROI3 in Groups A and B and moderate-to-strong negative correlation in Group C. Because of the characteristics of three-dimensional brachytherapy, in patients with BMI < 24.0 kg per m2, low-dose CT protocol can minimize radiation exposure and achieve precise, individualized treatment.

Effect of new radioprotective equipment on reducing radiation exposure of participants in percutaneous coronary intervention

Background: The ionising radiation generated in percutaneous coronary intervention has the largest hazard to medical staff among all interventional procedures, and thus has gained the attention of various researchers. Radioprotective shielding equipment is an effective measure; however, it has poor applicability to diverse interventional procedures. The aim of this study was to develop a new radioprotective shielding equipment for percutaneous coronary intervention and determine its effectiveness and applicability. Methods: This study developed a radioprotective cabin for percutaneous coronary intervention and used fluoroscopy and cine models of a digital subtraction angiography machine to compare the effectiveness of experimental (radioprotective cabin) and control (current radioprotection strategies) groups. Radiation equivalent dose rates were measured at 231 data points: 210 points were distributed on four vertical planes around the therapy bed and 21 points were evenly distributed around the thyroid, head, and gonad areas of a standardised patient. Results: Based on the cine model, there were statistically significant differences in the radiation equivalent dose rates between the control and experimental groups in the left plane, right plane, foot plane, head area, and gonad area (Z = −6.645, −5.615, −6.204, −2.647, −2.882, respectively; P &lt; 0.05). Based on the fluoroscopy model, there were statistically significant differences in the radiation equivalent dose rates between the two groups in the left plane, right plane, foot plane, and gonad area (Z = −6.060, −5.083, −5.203, −2.887, respectively; P &lt; 0.05). Conclusion: The radioprotective cabin developed in this study can effectively reduce the radiation equivalent dose rates in the standing area of medical staff and radiation-sensitive areas of patients without affecting the operation, which can be promoted and applied in percutaneous coronary intervention.

TPACK-Enhanced Geometry and Algebra for Primary School Teacher of KKG Cluster IV in X Koto Singkarak District, Solok Regency

In elementary school, a mastery of geometric and algebraic mathematical methods is necessary. Students in the discipline of algebra struggle with fraction addition and multiplication. Similarly, students struggle in geometry to compute the area of a flat plane. Group IV Koto Sani teachers in the Koto Singkarak District of the Solok Regency received this assistance in the form of workshops. From August to October 2022, there will be three meetings both in-person and online. The offered material is comprised of TPACK-based learning resources, such as Cuisenaire rods, flat media, and music boards. Based on the results of the initial and final surveys, it was determined that there was a 7% improvement in material comprehension, a 7% improvement in the ability to create media, and a 5% improvement in the ability to use media

Study on the Aperture Evolution Law and Seepage Mechanism of 3D Rough Structure Plane under the Shear–Seepage Coupling Test

In order to study the mechanical characteristics and seepage mechanism of the structural plane under the action of seepage water pressure, the shear–seepage coupling test was carried out. It was found that with an increase in seepage water pressure, the peak shear strength, and shear stiffness of the structural plane decreased, while the peak dilatancy angle, average dilatancy angle, peak shear displacement, initial flow rate, and peak flow rate increased. The profile JRC and 3D morphology parameters under different Y values increased as seepage water pressure increased, indicating that the wear degree of the structural plane decreased. The contact area, effective aperture, average aperture, and hydraulic aperture of the structural plane all increased in phase with the increase in shear displacement, and they all increased in trend with the increase in seepage water pressure. The distribution and evolution law of the structural plane aperture were analyzed by programming using scanning point cloud data and the normal displacement value of the structure plane. It was concluded that the aperture gradually increased with the increase in seepage water pressure.

A global view on star formation: The GLOSTAR Galactic plane survey

As part of the Global View on Star Formation (GLOSTAR) survey we have used the Karl G. Jansky Very Large Array (VLA) in its B-configuration to observe the part of the Galactic plane between longitudes of 28° and 36° and latitudes from −1° to +1° at the C-band (4–8 GHz). To reduce the contamination of extended sources that are not well recovered by our coverage of the (u, υ)-plane, we discarded short baselines that are sensitive to emission on angular scales &gt;4″. The resulting radio continuum images have an angular resolution of 1.″0 and a sensitivity of ~60 µJy beam−1, making it the most sensitive radio survey covering a large area of the Galactic plane with this angular resolution. An automatic source extraction algorithm was used in combination with visual inspection to identify a total of 3325 radio sources. A total of 1457 radio sources are ≥7σ and comprise our highly reliable catalog; 72 of these are grouped as 22 fragmented sources, for example, multiple components of an extended and resolved source To explore the nature of the cataloged radio sources, we searched for counterparts at millimeter and infrared wavelengths. Our classification attempts resulted in 93 H II region candidates, 104 radio stars, and 64 planetary nebulae, while it is suggested that most of the remaining radio sources are extragalactic sources. We investigated the spectral indices (α, Sv ∝ vα) of radio sources classified as H II region candidates and found that many have negative values. This may imply that these radio sources represent young stellar objects that are members of the star clusters around the high-mass stars that excite the H II regions, but not these H II regions themselves. By comparing the peak flux densities from the GLOSTAR and CORNISH surveys, we have identified 49 variable radio sources, most of them with an unknown nature. Additionally, we provide a list of 1866 radio sources detected within 5 to 7σ levels.

Investigation of the real contact area of tensile fractures with different normal stresses and sizes by using pressure-sensitive films

More than 240 experimental tests were conducted and the characteristics of real contact area of the mated tensile fractures were investigated by using pressure-sensitive films. The effects of normal stress, fracture size as well as rock type on the real contact area of mated tensile fractures were evaluated and discussed. The results show that the real contact area of the mated rock fractures has a parabolic increasing relationship with the normal stress ratio (the ratio of the applied normal stress on the fracture surface to the uniaxial compressive strength of the joint wall). Also, the size of the tensile fracture can affect its real contact area, and the larger the applied normal stress is, the more significant the size effect of the rock fracture on the real contact area is. Furthermore, lithology has a significant influence on the real contact area of the structural plane, which is also related to the applied normal stress. Under the same stress condition, the real contact areas of shale and granite fractures are the smallest, while that of green sandstone fractures is the largest. By analyzing the nominal normal stress and the real normal stress on rock fractures, it was found that even if the nominal normal stress applied on the rock fractures is only 1.5 MPa, the average real normal stresses can reach 20 MPa ∼ 45 MPa, which is about 15–30 times the nominal applied normal stress. The contact characteristics of tensile fractures were analyzed by adopting the cutting methods. It was revealed that within a mated tensile fracture, the smaller the JRC of an area is, the larger the real contact area will be. The results of this study are of great significance for revealing the characteristics and laws of the contact areas of tensile fractures, and the 248 sets of data specimens obtained from the tests can provide important support or reference for establishing mechanical models for rock mass contact.

PI Control of Loudspeakers Based on Linear Fractional Order Model

This paper aims at the proportional-integral (PI) control of the cone vibration of the electrodynamic loudspeakers system recently described using a linear fractional order model. After introducing the fractional order model of the circuit of these loudspeakers, firstly, a new method is developed to design a fractional order PI controller to place the poles of the system in a desired area of the complex plane which is called D-stabilizing. The design parameters of the method depend directly on the speed of the system output response, the cone vibration. Moreover, the offered fractional order controller avoids any non-minimum phase zero, which causes undesired undershoots in the output, for the closed-loop control system. Secondly, considering uncertainties in the coefficients of the model, a methodology is presented to determine up to how much the uncertainties can increase such that the controller is still able to maintain both D-stability and the absence of non-minimum phase zeros for the control system. Finally, the merit of the presented results and the superiority of the designed fractional order controller over its conventional integer order counterpart are illustrated through numerical simulations.

双源螺旋CT测量腹部脐层面VAT面积与冠心病的相关性研究

双源螺旋CT测量腹部脐层面VAT面积与冠心病的相关性研究

Pharyngeal airway dimensions in Iranian female young adults with different skeletal patterns using cone-beam computed tomography

To assess the oropharyngeal airway in Iranian female young adults with different skeletal patterns using cone-beam computed tomography (CBCT).This descriptive, cross-sectional study evaluated 105 CBCT scans of female patients between 18 and 35 years retrieved from the archives of a radiology clinic. The images were evaluated in axial, sagittal, and frontal sections. In the axial plane, the maximum and minimum cross-sectional area (CSA) of the airways at the oropharynx, minimum width (anteroposteriorly), and minimum depth (laterally) were measured using Mimics Medical software. The oropharyngeal volume was measured by NemoFAB software. The values were compared among the groups with different sagittal, vertical, and transverse patterns. The correlation of indices with airway measurements was analyzed using Monte Carlo Chi-square and Pearson's correlation coefficient.No significant difference was noted in oropharyngeal airway dimensions and volume among cases with different skeletal sagittal, vertical, and transverse patterns (P > 0.05) except for class III patients with normal transverse pattern in whom maximum CSA in low-angle group was larger than that in normal-angle group (P < 0.05) and class I normal-angle patients in whom maximum CSA in transverse normal group was smaller than that in constriction group (P < 0.05).Oropharyngeal dimensions were not significantly different in Iranian female young adults with different skeletal patterns.

Slope gradient impacts on rill morphological characteristics: Using indoor simulation experiment on loamy clay under certain rainfall intensity

In the present study, the rill morphological parameters and their spatial distributions were investigated using indoor rainfall simulation experiments in combination with 3D terrestrial laser scanning technique. Moreover, the optimal rill morphological indicators for rill erosion evaluation were selected based on the relationship of rill morphological parameters and erosion amount. The results showed that total rill length (L), rill density (ρ), maximum width (Wmax), the degree of contour line departure (μ) and shape ratio (η) increased with the increase of slope gradient, whilst the mean rill depth (Dmean), mean rill width (Wmean) and width/depth ratio (W/D) decreased with the increase of slope gradient. The spatial distribution pattern of each rill morphology parameter was also changed with slope gradient, showing differences in upper slope, central slope and lower slope. Most of rill morphological parameters were highly correlated with rill erosion amount, except the mean rill width (Wmean), degree of contour line departure (μ), and rill density (ρ). The plane area of rill (Parea) or the degree of rill dissection (δ) was selected as the optimal morphological parameter to predict rill erosion amount, followed by the maximum area of cross section (CSmax), the maximum rill depth (Dmax), and the mean rill depth (Dmean). In particular, the parameters of CSmax and Dmax are recommended for rill erosion estimation based on the convenience and ease of data acquisition.

Micromechanics prediction of dynamic modulus for asphalt mastic considering filler distribution characteristic: A new perspective

This study aims to provide a new perspective into the consideration of filler distribution characteristic in micromechanical modeling of asphalt mastic through combining fractal microstructure. To do this, three viscoelastic micromechanical models were improved by the preliminarily combination between micromechanical equivalence and fractal statistic principles. Particle size distribution (PSD) of filler was tested by a laser particle size analyzer. Asphalt mastics with different filler concentrations were fabricated. Dynamic shear moduli of asphalt and asphalt mastics was tested by a dynamic shear rheometer. The PSD of the circles intercepted by the plane and dimensionless area of the intercepted asphalt matrix were analyzed. The dynamic shear modulus ratio of asphalt mastic to binder were calculated based on the improved models. The effects of various parameters on the distribution of the ratio were investigated. Results show that the shifted R-R distribution function is capable of capturing the PSD of filler. The dimensionless area increases with increasing dimensionless diameter, but decreases with increasing filler volume fraction. The shear modulus ratio shows a three-stage reduction trend with dimensionless diameter, replying that the shear modulus of asphalt mastic appears as a random distribution in space. Meanwhile, the spatial distribution is influenced by filler volume fraction and thus there has difference between the stiffening effects of filler on various local regions in asphalt mastic. Poisson’s ratio of binder plays an enhanced role in the stiffening effect of filler, which is affected by the spatial locations within asphalt mastic. Modulus and Poisson’s ratio of limestone filler and modulus of binder have little effect on the distribution of the shear modulus ratio. The combination of micromechanical modeling and fractal characteristic is capable of determining the spatial distribution characteristic of effective properties for asphalt mastic. The local homogenization of asphalt mastic in terms of the modulus and its influence on properties of asphalt mixture should be focused on and conducted in future.

Equilibrium-Based Black-Scholes Option Pricing in Electricity Markets

In this article, a new model for option pricing using the Black–Scholes option pricing method under equilibrium of the option and day-ahead markets is presented. To analyze the performance of the Black–Scholes option pricing method in financial electricity markets, the model is compared with the equilibrium option pricing (Eq-Pr) model. To this end, first, the option pricing curves of the above-mentioned models on the option contract area (OCA) of the financial electricity market are drawn. Here, the option pricing curve means the computed premium price versus strike price, and the OCA is the area of the premium price-strike price plane in which both option buyers and sellers are willing to conclude option contracts. Then, overlap of the Black–Scholes option pricing curve with the OCA and its distance to Eq-Pr curve is assessed. The controversy among researchers about the applicability of the Black–Scholes option pricing in financial electricity markets is assessed by applying the proposed models to a test power system and the conditions in which Black–Scholes option pricing works are discussed.

Directional growth of quasi-2D Cu2O monocrystals on rGO membranes in aqueous environments.

The preparation technology of unconventional low-dimensional Cu2O monocrystals, which exhibit specific crystal planes and present significantly unique interfacial and physicochemical properties, is attracting increasing attention and interest. Herein, by integrating a high-temperature oxidation process under vacuum and a pure-water incubation process under ambient conditions, we propose the self-assembled growth and synthesis of quasi-two-dimensional Cu2O monocrystals on reduced graphene oxide (rGO) membranes. The prepared Cu2O crystals have a single (110) crystal plane, regular rectangular morphology, and potentially well conductivity. Experimental and theoretical results suggest that this assembly is attributed to the pre-nucleation clusters aggregation and directional attachment of Cu and O on the rGO membranes in aqueous environment and cation-π interactions between the (110) crystal plane of Cu2O and rGO surface. Our findings offer a potential avenue for the discovery and design of advanced low-dimensional single-crystal materials with specific interfacial properties in a pure aqueous environment.