esa-sceva/satcom-chunk-collection huggingface dataset:
## 6 Finite Element Analysis of Prestressed Hollow Slab  
### Establishment and Verification of the Finite Element Model for the Prestressed Hollow Slab  
Based on the actual structural size of the prestressed hollow slab, the ABAQUS finite element analysis software was used to establish a finite element model for a prestressed hollow slab beam (Figure 15).  
Figure 14: Dynamic displacement diagram of fatigue test process of steel plate strengthened component.  
Figure 15: Finite element model of the prestressed hollow slab.  
The finite element model has a total of 1971 units. The concrete unit adopted a 3D solid unit, the elastic modulus was 3.0 \(\times\) 10\({}^{4}\) MPa, and the Poisson's ratio was 0.2. Other material parameters were set according to the material parameter properties described in the experimental section of the text. ABAQUS provides three models to simulate the nonlinearity of concrete: a concrete dispersion cracking model, concrete plastic damage model, and concrete brittle cracking model. According to the main forms and causes of damage of the prestressed hollow slab beams, the main choice of concrete material in this paper was the plastic damage model, which could simulate the forms of damage of the concrete materials.  
By comparing the simulated values obtained using the ABAQUS software with the measured values obtained during the test, it was found that the changing trends in the midspan load-displacement curves of the two values were quite similar (shown in Figure 16). However, in the software simulation processing, the bond-slip between the steel bars, prestressed bars, and concrete was neglected; therefore, the load value obtained during the test was larger for a constant deflection. The load-displacement curves of the measured and simulated values underwent three stages: The first stage was the elastic stage, wherein the load and deflection increased proportionally. The second stage was the yield stage, wherein the cracking load of the prestressed hollow slab was 200 kN, and the slope of the load-displacement curve decreased owing to the decrease in stiffness caused by the cracking of the test plate. The third stage was the strengthening stage, wherein the load increased gradually, but the deflection decreased rapidly. The ultimate load was determined as the longitudinal reinforcement yield. In addition, the finite element simulation of the concrete damage can be seen in Figure 17. When a static load was applied to the prestressed hollow slab finite element model, the damage cracks mainly occurred at both ends of the bearing, which was consistent with the results of the actual static load tests. Therefore, the accuracy of the prestressed hollow slab finite element model was verified.  
Figure 16: Comparison of measured and simulated load-displacement curves of test plate.  
Figure 17: Damage diagram of prestressed hollow slab concrete.
###### Abstract  
The modular multilevel converter (MMC) has been widely adopted in high voltage direct current (HVDC) transmission systems due to its significant advantages. MMC-HVDC is developing towards multi-terminal direct current (MTDC) power grid for reliability enhancement. However, there exist a huge amplitude and a steep rise in fault current due to the low impedances of DC lines and MMCs, which threaten the security and reliability of the DC power grids. It is necessary to restrain the DC short circuit current in order to ensure the safe and stable operation of DC power grids. This paper gives a comprehensive review and evaluation of the proposed DC short-circuit current analysis and suppression techniques used in MMC-based MTDC power girds, in terms of MMC modeling, short circuit calculation, and suppression method. In addition, future trends of countermeasures to short circuit current in MMC-based MTDC power grids are also discussed.  
MMC-HVDC; DC power grid; DC short circuit current; MMC modelling techniques; short circuit current calculation method; short circuit current suppression method +
Footnote †: journal: Applied Sciences
## 2 A Brief Discussion on LEACH, EESR and Sub-Cluster LEACH Protocols
### Sub-Cluster LEACH  
As studied above, LEACH protocol [13; 14; 15; 31; 32] is a traditional energy efficient protocol based on a hierarchical approach. However, to make it more energy efficient and reduce the complexity of data transmission, sub-clustering can be introduced. As in LEACH protocol, for a particular round, the network is divided into clusters and clusters aggregate the data, and later on aggregated data are transmitted to the BS. This task is accomplished by performing clusters, denoting some sensor nodes as CH nodes and N-CH nodes, as introduced before. Nevertheless, a major problem is related to battery consumption of CH nodes after each round. The energy drains to extreme level in some occasions, in a way that a node gets to a dead state. To change this situation, sub-clustering within the cluster can stabilize the depletion of energy up to some extent. In a particular round, each cluster has one CH node but now two more nodes will be selected within a cluster. This is done on the basis of remain energy parameter. These sub-cluster nodes are denoted as sub-cluster heads (Sub-CH), and their number is restricted to two for each cluster. They aggregate the data from corresponding nodes and compress them. This is totally dependent on the distance from the CH node or Sub-CH node. The distance is calculated with link quality parameter. If the distance from the CH node is far greater than from a Sub-CH, then N-CH will transfer the monitored data to the Sub-CH node, and otherwise directly towards the CH node. The data aggregated at the Sub-CH node are  
Figure 2: EESR protocol graphical representation.  
compressed and forwarded to the CH node. Later, aggregated data at the CH nodes are sent directly from N-CH nodes and Sub-CH nodes, jointly transmitted to BS as shown in Figure 3.  
The idea of the sub-cluster can be summarized as follows:  
1. Select one, or at most two Sub-CH nodes in each cluster.
2. Selection depends on remain energy parameter and nodes concentration.
3. N-CH selects either CH or Sub-CH nodes of the same cluster to transfer the data. This can be done by distance calculations from N-CH to CH and N-CH to Sub-CH.
4. The link quality parameter is used to calculate the distance.
5. Each N-CH transmits its data to CH nodes or Sub-CH nodes. The Sub-CH node, later, transmits the aggregated data to CH by compressing them.
6. Data are collected by CH from N-CH and Sub-CH nodes.
7. Jointly, N-CH data and Sub-CH data are transferred to the BS.
8. A Sub-CH node also acts as an intermediate node for transmitting the aggregated data from CH nodes to BS, only if the Sub-CH node is nearer to BS. Otherwise, another N-CH node is selected as the intermediate. However, first priority is given to the Sub-CH node as an intermediate node.
# Review of Ka-Band Power Amplifier
## 3 Topologies
### Cascade
Compared with the LDO proposed in [49], the body network is so simple that it is suitable for most millimeter-wave amplifiers. A Class AB cascode PA in 130 nm SiGe with noninverting transformer for mobile satellite communication (SATCOM) was reported [55]. The 1-stage cascode power amplifier achieved P\({}_{\text{1 dB}}\) of 12 dBm, P\({}_{\text{sat}}\) of 14 dBm and peak PAE of 25% at 28 GHz. In the latest study, [PERSON] proposed a cold-FET-based interstage matching network to improve the linearity and efficiency, which is designed in 60 nm CMOS (see Figure 10a) [34]. This matching network improves the linearity of the 2-stage cascode PA by providing the PA gain-expansion and phase-lag characteristics. The PA achieved 17.1 dBm output power and the PAE remained above 38.2%. Since the beginning of the 21 st century, the demand of PA covering multi-frequency band has been growing faster and faster [56]. [PERSON] proposed a concurrent dual-band PA in 180 nm SiGe BiCMOS with a new synthetic matching network technique (see Figure 10b) [57]. The technique works by combining two separate single-band matching networks into a single network, so the PA can work in single-band mode (25.5 or 37 GHz), as well as concurrent dual-band mode (25.5 and 37 GHz). The PA, composed of 2-stage common-emitter (CE) cascode, achieves peak PAE of 7.1% and more than 17 dB gain at dual-band mode. Figure 9: (a) The 3-stage CS cascode PA in 65 nm CMOS and LDO [49], (b) 2-stage differential cascode PA in 40 nm CMOS [54]. The breakdown voltage of the power amplifier in the CMOS process is low, but the cascode structure can greatly improve the power supply voltage and reduce the device sizes. As can be seen from Table 2, all chips have high integration and small area. However, the cascode structure also introduces large parasitic capacitors, resulting in low gain and efficiency compared with other structures.
# Structural Design and Optimization of Herringbone Grooved Journal Bearings Considering Turbulent
## 3 Results
### The Influence of Groove Depth on the Performance of HGJBs  
The depth of the groove has a direct impact on the storage capacity and flow pattern of the lubricant. We kept other parameters unchanged, the radius clearance c was 0.02 mm, took the groove depth as 0.5c, 0.8c, 1.0c, 1.5c, and 2c; and the influence of the groove depth on the performance of the bearings with different structures was analyzed as shown in Figure 18.  
Figure 18: Cont.  
Figure 18 shows that as the groove depth increases, the bearing load capacity shows a gradual decreasing trend; the side leakage increases, and the friction power decreases slowly with the increase of the groove depth. The temperature rise gradually decreases and stabilizes. When the groove depth is 0, the HGJBs becomes an ordinary journal bearing at the moment, so the bearing load capacity will reach the maximum. On the one hand, by increasing the groove depth, the existence of the groove will destroy the continuity of the bearing oil film pressure; on the other hand, as the groove depth increases, it will cause the generation of cavities, resulting in a decrease in the bearing load capacity. When the eccentricity is 0.5, the maximum bearing load capacity of the convergent HGJBs is 26.43% larger than the minimum bearing load capacity, and the maximum friction power is 3.06% larger than the minimum friction power. The maximum bearing load capacity of constant-width HGJBs is nearly twice as large as the minimum bearing load capacity, and the maximum friction power is 6.8% larger than the minimum friction power. The depth of the groove has a significant effect on the bearing load capacity but not on the friction power.  
When the depth of the groove is small, according to [PERSON]'s law of shear, the shear force of the lubricating oil will become larger, and the dynamic pressure effect of the bearing will be significant at this time. As the groove depth increases, the stiffness coefficient gradually decreases. When the groove depth is small, the stiffness coefficient and damping coefficient decrease quickly, which shows that it is more sensitive to the change of groove depth. As the groove depth increases, the damping coefficient basically shows a linear decreasing trend. When the eccentricity is 0.5 and the groove depth is 0.5c, the stiffness coefficient of the convergent HGJBs is 65.16% larger than that when the groove depth is 2.0c.  
Considering factors, such as bearing load capacity and temperature rise and stiffness, the groove depth of the convergent HGJBs should not be too large, otherwise the bearing load capacity and stiffness will be poor; it should not be too small, otherwise the temperature rise will be too large. Therefore, the groove depth can be selected to be between 1.0c -1.2c. For constant-width HGJBs, the groove depth can be selected to be between 1.0c -1.2c.
## 5 Application Case
### Computational Model and Parameters  
#### 5.2.1 Computational Model  
According to the contour map of the Yanqianshan Iron Mine (Figure 10b), a three-dimensional mesh model (Figure 11) is established based on the representative Section Line IV. The model has a large size: 2560 m in length and 724 m in height. If the model is created by means of equal-sized tetrahedral meshes, the number of elements will be large, and the calculation efficiency will be unsatisfactory. To reduce the number of elements, smaller tetrahedral meshes are used near the excavation site, and larger tetrahedral meshes are used elsewhere.  
Figure 11: The tetrahedral mesh model (Section Line IV in Figure 10b).  
Figure 10: The geographic and topographic maps in the Yanqianshan iron mine (the geographic map comes from [[https://earth.google.com](https://earth.google.com)]([https://earth.google.com](https://earth.google.com)), accessed on 10 April 2021).  
The boundary condition in the numerical analysis is set mainly in terms of the stress, displacement, and their combination. In this study, the displacement boundary condition is used to constrain the node movement, where the full constraint is set at \(z=-600\) m, i.e., the displacement in the three directions is limited. At \(x=0\) m and \(x=2560\) m, the displacement constraint in the x-direction is set; at \(y=0\) m and \(y=300\) m, the displacement constraint in the y-direction is set; the remaining positions are free boundaries. The initial stress field is obtained by setting the magnitude of the acceleration due to gravity as \(-10\) m/s\({}^{2}\), the constitutive model is Mohr-Coulomb, and the maximum unbalanced force ratio is set as \(1\times 10^{-5}\). The dimensions of each excavation are listed in Table 3.
## 3 Results and Discussion
### Thermodynamics of the Adsorption Process  
The main thermodynamic parameters (free energy (\(\Delta G^{\circ}\)), enthalpy (\(\Delta H^{\circ}\)) and entropy (\(\Delta S^{\circ}\))) for the adsorption process of AY 42 and AR 213 dyes were calculated using the results obtained for the Langmuir model.  
The Gibb's free energy (\(\Delta G^{\circ}\)) was calculated using the Equation (9),  
\[\Delta G^{0}=-RT\ln K_{L} \tag{9}\]  
and the enthalpy (\(\Delta H^{\circ}\)) and entropy (\(\Delta S^{\circ}\)) values for adsorption process were determined from the van't Hoff Equation (10),  
\[\Delta G^{0}=\Delta H^{0}-T\Delta S^{0} \tag{10}\]  
where \(R\) is the general gas constant (8.314 J/Kmol), \(T\) is the absolute temperature and \(K_{L}\) is the Langmuir adsorption constant, obtained from the isotherm plots. The \(\Delta H^{\circ}\) and \(\Delta S^{\circ}\) parameters were evaluated from the slope and intercept of the linear plot of \(\Delta G^{\circ}\) versus \(T\).  
The results obtained for thermodynamic parameters are presented in Table 11.  
The negative values of Gibb's free energy (\(\Delta G^{\circ}\)) indicate that the adsorption process of the AY 42 and AR 213 dyes from aqueous solutions on PM4 was spontaneous [74]. The positive values of the enthalpy variation (\(\Delta H^{\circ}\)) reveal the endothermic nature of the adsorption process, and confirm the experimental results obtained from the influence of temperature study, which indicate that the adsorption capacity increases with increasing temperature [75]. The negative values of the entropy variation (\(\Delta S^{\circ}\)) that characterize the adsorption process suggest that the dye molecules decrease their randomness at the solid-liquid interface during the adsorption [76].
# Determination of Point-to-Point 3D Routing Algorithm Using LiDAR Data for Noise Prediction
## 3 Methodology
### Building Corner Extraction Step 1 to Step 3  
In order to extract the building corners and the Building edges from the LiDAR data [36] (Further results are provided in the Supplementary Section S2.2).  
Step 1: Extraction of elevated data after subtraction of BEM from DSM, where building of RGIPT campus is shown in (Figure S6a-d) of Supplementary File.  
Step 2: Extraction of building edges and corner points from the elevated data in step 1. Corner points for each building were determined (Figure S7a-c of Supplementary File) and stored separately in an array by using the minimum and maximum criteria of x and y.  
Step 3: Building corners for each building were extracted in the form of array [33]. Where (\(x1\), \(y1\)) is one of the building corners.  
\[\begin{array}{l}Building\;1=[(x1,y1),(x2,y2),(x3,y3)\;.\;.\;.\;.\;.\;.\;.\;. \;.\;.  
Figure 4: Flow chart explaining route determination in short.  
Figure 5: (**a**) Principal route with respect to route over the top and reflection routes (Routes are P1, P2, P3, and P4). (**b**) Principal route with respect to route around the right side and reflection routes (Routes are P5, P6, P7, and P8). (**c**) Principal route with respect to route around the left side and route of reflection (Routes are P9, P10, P11, and P12).  
To understand the noise propagation, noise route determination was needed. A simulated area that consisted of a set of buildings was used for this purpose. The area contained buildings A, B, C, D, E, and F, which were of different heights and orientations. The area also contained a pair of source and destination points. The simulated area is shown in Figure 5(a).
# Demodulation of EM Telemetry Data Using Fuzzy Wavelet Neural Network with Logistic Response
## 4 Examples
### Comparison of the FWNN with BP Using Pseudo-Synthetic Data
(**a**) The generated code, representing transmitted information; (**b**) transmitted signal with noise; (**c**) Adaptively processed signal; (**d**) post-processed transmitted signal with reduced data samples; (**e**) recovered signal code using an FWNN with a logistic response. determination of spectral characteristics in the field and reducing the working time of adaptive processing. Additionally, synthetic data analysis and pseudo-field data processing show that the algorithm can solve practical engineering problems and provide a reference to field technicians.
## 1 Introduction
Comparisons with well-known classification algorithms showed that MFC has better classification performances than Naive Bayes [15] and Lazy Bk [16] and is comparable with respect to the ones obtained by using Decision tree J48 [17] and Multilayer Perceptron [18] algorithms. On the other hand, the main drawback of this method is the high computational complexity that is reached when the number of features increases. In [19] a hybrid fast classification method based on F-transform and Principal Component Analysis (for short, PCA) [20; 21; 22; 23] is proposed. This method is tested to classify images; the results show that it improves the success rate and computation time obtained by applying the F-transform algorithm. PCA is a well-known dimensionality reduction multivariate statistics technique whose goal is to reduce the number of features of a dataset by losing the least amount of information possible. PCA is one of the most used feature extraction techniques in data analysis. Its strong point is to be able to reduce the dimensionality of the data, while preserving their information content. In this research, we propose a hybrid classification method applied to massive data including the PCA and the multidimensional F\({}^{1}\)-transform techniques. The main goals of the proposed method are:  
* Improve the MFC classification performances; the application of the multidimensional direct and inverse F1-transform allows to increase the accuracy and precision of the classifier with respect to the use of the multidimensional F-transform. * Significantly reduce the time and memory consumption executing the PCA feature extraction algorithm in the preprocessing phase to reduce the dimensionality of the data. In Section 2, the concepts of multidimensional direct and invers F\({}^{1}\)-transform are introduced and the PCA algorithm is synthetized. Section 3 is focused on the analysis of the architecture and functional characteristics of our classification method based on the multidimensional F1-transform. The results of experimental tests are discussed in Section 4. Finally, in Section 5 the conclusions and future perspectives are included.
# Dynamic Stall Characteristics of the Bionic Airfoil with Different Waviness Ratios
###### Abstract
For dynamic stall, the results showed that the aerodynamic performance of the modified airfoil was stable at a high angle of attack, which resulted in a reduction in the area of the lift coefficient hysteresis loop. [PERSON] and [PERSON] [24] experimentally studied the effect of a wavy tubercle edge, inspired by humpback flippers, on the dynamic performance of an airfoil at angles of attack from \(0^{\circ}\) to \(50^{\circ}\). Their results showed that the leading-edge tubercles on the flippers acted as a passive flow control mechanism controlling or delaying dynamic stall. [PERSON] et al. [25] presented a comprehensive review of recent research on wavy leading edges. Related experimental and numerical results show that the flow pattern of the wave-shaped front edge structure is entirely different from that of the traditional airfoil. In addition, the leading edge of the nodule can solve aerodynamic problems such as flow separation, noise, and dynamic stall. This review described research on different airfoils and the performance improvements that had been obtained. It also summarized the main contributions of previous studies and identified their shortcomings. The influence of a tubercle leading edge on dynamic stall characteristics was described. [PERSON] et al. [26] presented a detailed review of experimental studies of dynamic stall. They discussed the effects of various parameters, such as reduced frequency, Reynolds number, Mach number, and airfoil geometry, on dynamic stall characteristics. As [PERSON] [27] emphasized, although research on the front structure has been carried out for many years, there is still a need for further research on this topic. From the literature review presented above, the effects of leading-edge protuberance on the static and dynamic aerodynamic performance of the airfoil have been studied numerically and experimentally. The airfoil with a wavy leading edge can maintain a high lift in the static stall by delaying the stall. In the case of a dynamic stall, a wavy leading edge can suppress the dynamic stall hysteresis of the airfoil. However, there have been few reports on the effects of wavy leading edges with different waviness ratios on the dynamic stall performance of airfoils. Thus, the dynamic stall characteristics of the airfoils with varying ratios of waviness are investigated in the present research study. The force coefficients, instantaneous flow patterns, and pressure distribution are obtained and compared with those of the conventional NACA 0015 airfoil. The flow control mechanism of the wavy leading edge of the airfoil is revealed based on the numerical results. This study expects to provide a valuable reference for improving the performance of aircraft and impeller machinery through the optimal design of the blade.