esa-sceva/satcom-chunk-collection huggingface dataset:
# Wind Load Characteristics of Wind Barriers Induced by High-Speed Trains Based on Field Measurements
## 2 Field Measurements
### The Wind Barrier Model and Measurement Points  
A ventilating wind barrier is generally adopted in non-wind regions. Holes are distributed evenly on the wind barrier to achieve a certain wind porosity (the proportion of the total areas of holes to the total area of the wind barrier) [16]. The influence of the wind barrier on the train-induced wind load acting on the wind barrier itself mainly includes the height of the wind barrier, the wind porosity, and the shape of the holes. Since the aerodynamic characteristics of a train subject to crosswind depend not only on the shapes of the vehicles, but also the infrastructure and the wind barrier, optimization of the wind porosity, height, and other parameters of the wind barrier is usually conducted to meet the requirements of different wind environments. However, the geometries of the wind barrier are slightly different under different wind environments. The wind porosity of the wind barrier is usually realized through holes or grille bars. However, the holes or grille bars will affect the arrangement of wind pressure measurement points. Thus, the generality of the test results cannot be achieved when considering the wind porosity. Moreover, the test results for the wind barrier without porosity demonstrate an extensive representation because of the largest wind load acting on this type of wind barrier. Therefore, the porosity of the test wind barrier in this paper was set to be 0%, and the height of the wind barrier was set to be 3.0 m, referring to the suggested height in existing literature for the sake of the generality of the test results [27]. In order to eliminate the end effect, the wind barrier model consisted of two compensation segments (the length of each segment was 3 m) and a test segment (the length was 0.2 m). The test segment was located between the two compensation segments. The compensation segments were made of wood boards, and the test segment was made of plexiglass. As shown in Figure 3, the distance between the installed wind barrier and the train was 1.8 m. Considering the side of the wind barrier near the train will experience the majority of the wind loads, only this side of the wind barrier was selected for wind pressure measurements. There was a total of 10 measure points, as illustrated in Figure 3. The interval between each measuring point was approximately 30 cm. It should be noted that measuring point 9 was parallel to the rail surface in Figure 3. The pressure measurement method was adopted to acquire the wind loads acting on the wind barrier.
# Remote Sensing of Environmental Changes in Cold Regions: Methods, Achievements and Challenges
## 2 Principles and Methods
### Remote Sensing of Frozen Soil
#### 2.3.1 Landscape Freeze/Thaw States
However, the SMAP and AMSR2 products show generally enhanced spatial delineation of FT patterns due to the respective finer 9-km and 6-km resolution gridding of these products, relative to the 25-km resolution SSM/I global grid product. The SMAP L-band products also have greater soil FT sensitivity than the K-band retrievals from AMSR2 or SSM/I [152]. In addition, the SMAP radar produced operational FT retrievals over northern (\(\geq\)45\({}^{\circ}\)N) land areas with \(\sim\)3-km resolution and 1-3-day fidelity until the radar transmitter failed in July, 2015; however, these data are overlapping with SMAP radiometer based FT records which share the same satellite antenna receiver [152]. FT retrievals have also been acquired from L-band Global Navigation Satellite System (GNSS) signals captured from the SMAP radar receiver, which has provided kilometer scale observations of FT seasonal transitions.
## 4 Conclusions  
1. When the confining pressure on the rock mass is small, the mean cutting force of the cutting head is greater than that without confining pressure; The increase of confining pressure on the rock mass is  
Figure 21: Rock cutting force in the y-direction if the top and rear side of the rock mass are free surfaces.  
Figure 22: Comparisons of mean cutting forces between different boundary conditions.  
pressure on the rock mass would be helpful to reduce the mean cutting force on cutting head and improve the cutting performance.
2. During the process of rock cutting, the rotating direction of the shearer drum have influence on the cutting performance of shearer drum. When the cutting head rotates in the clockwise direction, the cutting force is greater than that in the anti-clockwise cutting direction of cutting head.
3. The cutting force on the shearer drum could be influenced by the unconstrained surface on rock mass. The unconstrained surfaces on rock mass are helpful to reduce the cutting force on the shearer drum. Among the different boundary conditions, the best boundary condition to improve the cutting performance is to create a free surface on rock mass that is close to the end plate of the shearer drum.  
This article proposes a method that helps improve the cutting performance of the drum by increasing the free surface of the rock mass to reduce the cutting resistance. At present, there are some technologies for free surface excavation on rock mass, such as combined rock breaking with saw blades and water jet assistant rock breaking method. However, whether the cost of free surface excavation could be covered by the benefit of performance improvement of the shearer drum and which technology of free surface excavation could get the job done would be topics that need further research in the future.  
Conceptualization, L.W. and K.G.; methodology, K.G.; software, W.X.; validation, W.X. and K.J.; formal analysis, W.X.; writing--original draft preparation, W.X.; writing--review and editing, W.X., K.J., Y.B., M.X. and S.M.; project administration, L.W.; funding acquisition, K.G. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number 52174146, and Special Project for Science and Technology Innovation of China Coal Technology and Engineering Group, 2023-TD-ZD003-006.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.  
Author [PERSON] was employed by the company China Coal Technology & Engineering Group Shanghai Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
# A Real-Time Map Restoration Algorithm Based on ORB-SLAM3
###### Abstract
Due to this limitation, the SLAM system cannot generate a complete map. Therefore, this paper proposes a real-time map restoration method, which avoids the limitation of monocular initialization and generates a complete map with higher accuracy. The improvement of this algorithm is as follows:  
* After the scale optimization of ORB-SLAM3, in order to obtain a complete map, all frames before successful initialization are quickly tracked back. In this process, the bag-of-words is used to match the feature points, and the MLPNP [27] is used to estimate the pose. * In order to offset the extra time consumption caused by reverse tracking, the loop closure detection of each frame is accelerated. The process uses the mean, standard deviation and correlation of grayscale histogram to pre-process and pre-screen the loop candidate frames. It can improve the quality of the loop candidate frames and further reduce the number of invalid calculations in the loop closure verification. The remainder of this paper is organized as follows. Section 2 discusses in detail the overall framework of the system, the details of reverse tracking and the method of using the grayscale histogram acceleration. The effectiveness of the proposed algorithm is verified on the Euroc dataset, and the comparison of the time efficiency and accuracy with ORB-SLAM3 algorithm is included in Section 3, followed by the conclusion in Section 4.
## 4 Results and Discussion
### Particle Movement  
According to [PERSON] et al. [29], due to the existence of a geogrid structure, the particle rotation resistance is expected to increase. Particle resistance has an important impact on the interaction performance between the ballast and the geogrid. The resistance is mainly caused by the friction and embedment between the ballast and the geogrid, which leads to the translation and rotation of the ballast. Figure 11 shows the displacement and rotation of the particles around the geogrid at a 50-mm pullout displacement. In order to provide insights into particle movement, three sections--plane 1, plane 2 and plane 3--were chosen, as shown in Figure 10(a). The rotation was calculated as the angle between the clumps' main axes from the initial state (0 mm) to the final state (50 mm).  
Figure 10: Deformation behavior of biaxial and triaxial geogrid: (**a**) geogrids in experiments; (**b**) geogrids in DEM-FDM model and (**c**) geogrids in DEM model.  
stronger the interlocking between the geogrid and the ballast in this area. For the sections at three different positions (planes 1-3), the maximum displacement and rotation of the triaxial geogrid appear near plane 3. Meanwhile, conversely, the maximum displacement and rotation of biaxial geogrid appear near plane 2.
# Resurgence of a Nation's Radiation Science Driven by Its Nuclear Industry Needs
## 3 Exemplar Results
### Sensing of Gases Produced by Radiolysis
Examples of radiolytic consumption of H\({}_{2}\) and O\({}_{2}\) are provided in Figure 6 for several metal oxides exposed to gamma radiation. Off-the-shelf metallic components were used to build the sample assembly, which included a 10.5 cm\({}^{3}\) sample vessel and a single inlet/outlet fitted with a bellows sealed valve [23]. Figure 6a,b shows the results of the gamma irradiation of a 5:5:90 H\({}_{2}\)-O\({}_{2}\)-Ar mix at 1 bar without any metal oxide present and in the presence of either ceria or zirconia and supports the results of studies of PuO\({}_{2}\)[33; 34]: under irradiation, H\({}_{2}\) combines with O\({}_{2}\), and this depletion happens more readily in the presence of a metal oxide [23]. Measurement of the H\({}_{2}\) concentration post-irradiation was conducted using an SRI gas analyzer fitted with a 1 mL sample loop, X13 molecular sieve column, and thermal conductivity detector. The sample vessel was connected directly to the sample loop, which is fitted with a pressure transducer so that the amount of gas in the sample vessel is known after irradiation. Figure 6a,b indicates that a steady state between the radiolysis of water adsorbed onto the surface of the metal oxide and the recombination of H\({}_{2}\) and O\({}_{2}\) is not reached. Analysis of a 1:1:98 H\({}_{2}\)-O\({}_{2}\)-Ar mix gamma irradiated over thoria using the same off-line gas chromatography set-up is shown in Figure 6c,d [35]. In these experiments, O\({}_{2}\) depletion as well as H\({}_{2}\) depletion was determined. A fuller explanation of the effects observed in the thorium oxide system will be published elsewhere. Figure 6: Gas radiolysis experiments using gamma radiation with analysis by gas chromatography. (**a**,**b**) H\({}_{2}\) consumption in a 5:5:90 H\({}_{2}\)-O\({}_{2}\)-Ar atmosphere. (**a**) is the gas phase only and (**b**) is in the presence of CeO\({}_{2}\) and ZrO\({}_{2}\)[23]. (**c**,**d**) are from a 1:1:98 H\({}_{2}\)-O\({}_{2}\)-Ar atmosphere irradiated over 8 g of thoria and show the change in H\({}_{2}\) and O\({}_{2}\), respectively [35]. These experiments show that there are rich dynamics waiting to be explored, which involves radiolytic production, depletion, and radiation aging of samples. What is needed is a systematic approach to studying these phenomena whereby a longitudinal study could be made in order to investigate radiolytic processes in both liquid and headspace as well as the effects of solid-phase radiation damage on sample aging. Use of the gas probes to take measurement in situ is the first step towards uncovering these rich dynamics. Adaptation of the gas probe system for flexible and efficient gamma irradiation studies is underway (see Section 4.1).
## 2 Materials and Methods
### Deposition Parameters  
A Vision LWI VERGO-Workstation Nd:YAG laser (wavelength of 1064 nm, max pulse energy: 70 joule, peak power 17 kW, voltage range 160-500 V, pulse time 1-20 ms, spot size 250-2000 \(\upmu\)m) with an automatic x-y stage (lateral resolution: 10 \(\upmu\)m) was used to produce a silicon nitride coating. To achieve homogeneous coatings on the various substrate materials, the laser source parameters and the number of layers were adjusted through trial and error before each treatment. The pulse time was optimized to reduce surface overheating (and microstructural changes in titanium) or burning, while the voltage was selected as the lowest value that could grant at least a coverage of about 33% of the surface on the first cladded layer. The optimized parameters are listed in Table 1.  
A layer of silicon nitride powders of about 50 \(\upmu\)m was placed on the surface of the samples and then heated with a 2 mm laser spot size under constant N\({}_{2}\) gas flow (1.5 atm). To cover all the surface substrate, the stage moved on the x-y stage with a step of 1 mm, in order to overlap the single laser spots and create a more homogeneous layer.  
For the ZTA, the Y-TZP, and the Ti6 Al4V, three cladding layers were required to achieve full coverage. Before depositing the next layer, the substrate was rotated by 90\({}^{\circ}\) to form a cross grid. On the other hand, only one layer was applied to the LDPE substrate as laser melts polyethylene. Attempts at a second layer resulted in polymer carbonization.
# Ultrasonic Deicing Efficiency Prediction and Validation for a Flat Deicing System
## 5 Conclusions  
In this paper, a flat deicing system using ultrasonic waves to detach the ice layer from the host structure was studied. The feasibility of the deicing system was validated in both FE simulations and experiments. In FE simulations, both harmonic analysis and dynamic analysis were conducted. In the harmonic analysis, deicing parameters and deicing frequencies were given. For different configuration, a factor (DEF) was proposed to estimate and predict deicing efficiency. Based on optimal configuration, four icing cases were discussed for further validation of DEF. Simultaneously, the relationship between shear stress distributions and deicing was explored. In dynamic analysis, wave propagation and the deicing process were investigated. Finally, deicing experiments were performed to verify the feasibility of the deicing system and the reasonableness of predicted results in FE simulations.  
Based on the results above, the following conclusions were drawn:  
1. A parameter design method was proposed according to simulation results on the supercomputer. The optimal configuration (the radius and the thickness of the PZT actuator) and deicing frequency were also given.
2. The coefficient deicing efficiency factor (DEF) was proposed based on FE simulation, which can estimate and predict the deicing efficiency. With the help of this factor, the effect of the different model and deicing parameters on deicing efficiency can be calculated and compared. For shear stresses distributions, the more concentrated the shear stresses are on the edges of ice/substrate interface, the better for deicing. This can be one of the potential ways to achieve deicing more effectively.
3. The calculation results of harmonic analysis and dynamic analysis are consistent. Harmonic analysis can obtain deicing stress and deicing results more concise and clearer. Wave propagation, reflection, superposition, and other processes are better displayed in dynamic analysis, which can help to understand the deicing process and provide guidance for further optimization. For different models and problems, these two analyses should be used rationally to achieve the purpose of obtaining the expected results with lower calculation costs.  
Conceptualization, J.Z.; Data curation, Q.X.; Formal analysis, Z.S., Z.K., Q.X. and Y.T.; Investigation, Z.S.; Methodology, Z.K. and Y.Z.; Software, Y.T.; Writing--original draft, Z.S.; Writing--review & editing, J.Z. and Y.Z. All authors have read and agreed to the published version of the manuscript.  
This work was funded by National Natural Science Foundation of China (Grant No. 11772098).  
The authors declare no conflict of interest.  
Figure 20: The trend of detached area and deicing efficiency factor (DEF) for four different icing cases.
## 7 Adaptive Single-Point and Multi-Point Equalization
### SISO/SIMO Approaches
#### 7.1.2 Frequency Domain Approaches  
Working in the frequency domain, a single-point RRE technique was proposed in [177]. Here, the loudspeaker and microphone signals are split into subbands (a 20-band filterbank) and the equalization is achieved by adaptively updating the filter weights in these subbands. The approach is interesting because it combines simplicity, robustness towards peaks and notches of the room response, and the ability to track room response variations. It was improved in [178] by introducing a frequency-dependent step size. In this way, it is possible to optimize the adaptive equalization in each subband, improving the overall convergence speed. In [179], a further improvement of the previous methods [177, 178] has also been presented to cope with the online identification of the impulse response. In particular, the room response estimation is obtained by means of inserting artificial test signals in such a way that they remain inaudible to listeners by exploiting frequency masking. The signal is then analyzed in the frequency domain to identify the test signal and to determine the RIR. In [180] the approach of [177, 178] was elaborated and improved by developing a multi-point solution. After identification in frequency bands, a fractional octave smoothing is applied to the impulse responses, and a prototype filter is computed from the mean of the room magnitude responses. The obtained results have shown that the performance of this rather simple structure can be improved by considering a multi-point solution, which results in an increased width of the equalized zone. In [84], the approach of [180] was further elaborated considering frequency warping in the low-frequency region to improve perception. Specifically, the room responses at different positions in the zone to be equalized are estimated in the warped domain and the common trend of these responses is extracted as a prototype function. This allows the equalizer resolution to be increased at frequencies where the human auditory system is more sensitive. Adaptive versions of the filterbank techniques of [112, 113, 114, 115] could also be used for the same purpose.
# Hardware Acceleration of Tsunami Wave Propagation Modeling in the Southern Part of Japan
## 2 Data and Methods  
### Shallow Water System  
Following most tsunami phenomena researchers, we simulate wave propagation with the help of a version of a shallow water system in the following form:  
\[H_{t}+\left(uH\right)_{x}+\left(vH\right)_{y}\ =\ 0\]  
\[u_{t}+uu_{x}+vu_{y}+gH_{x}\ =\ gD_{x} \tag{1}\]  
\[v_{t}+uv_{x}+vv_{y}+gH_{y}\ =\ gD_{y}\]  
where \(H(x,y,t)=\eta(x,y,t)+D(x,y)\) is the distance from the sea surface to the bottom; \(\eta\) is the sea surface displacement relative to the mean sea level (wave height); \(D(x,y)\) is the water depth (which is assumed to be known at all grid points); \(u\) and \(v\) are the water flow velocity components in the \(x\) and \(y\) directions, respectively; and \(g\) is gravity force acceleration, see [6; 7]. Note that lower indices \(t,x,y\) in (1) indicate partial derivatives with respect to time and space variables.  
The shallow water system (1) does not take into account dispersive effects because in the case of local propagation of sufficiently long tsunami waves, these effects have no time to valuably change the wave parameters at the coast. The use of the shallow water approximation is typical among tsunami researchers.  
An extended reference list exists concerning the numerical treatment of nonlinear PDE systems of hyperbolic type, to which system (1) belongs. In the aforementioned software MOST, the splitting method with respect to spatial variables is widely used for calculation.
## 7 Case Study and Comparison with the Field Data
### Conceptualized Groundwater Calculation Model  
In practical engineering, the stratigraphic conditions, hydrogeological conditions and boundary conditions are often complex and involve many factors. To facilitate the analytical solutions presented in this study, it is necessary to focus on the main aspects of the problem and simplify the original problem. Based on the overview of the excavation pit project and the site's hydrogeological conditions, the upper layer consists of poorly permeable clay and silt, considered as an aquiclude, while the underlying fine sand layer is the main confined aquifer. The thickness of the confined aquifer in the calculation model is set to 30 m, and the depth of the waterproof curtain embedded in the confined aquifer is 20 m, which makes the curtain a suspended cut-off wall. Preliminary pumping tests indicate that the confined layer at the site primarily relies on surface water replenishment from the Yangtze River, so the lateral boundary is considered a constant-head boundary. Additionally, the aquifer is assumed to be isotropic, with a permeability coefficient of 17.3 m per day. The specific calculation parameters of the model are detailed in Table 3, and by utilizing symmetry, the right region of the conceptualized calculation model is depicted in Figure 11.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Soil Layer**} & \multirow{2}{*}{**Soil Type**} & \multirow{2}{*}{**Thickness (m)**} & **Unit Weight (kN/m\({}^{3}\))** & \begin{tabular}{c} **Effective** \\ **Friction Angle** \\ **(°)** \\ \end{tabular} & \multirow{2}{*}{\
\begin{tabular}{c} **Effective** \\ **Cohesion (kPa)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Permeability** \\ **Coefficient** \\ **(cm/s)** \\ \end{tabular} } \\ \hline I & Silty Clay & 2.0 & 17.5 & 11.5 & 10.0 & \(2.0\times 10^{-6}\) \\ II & Sandy Silt & 2.0 & 19.0 & 30.0 & 1.25 & \(2.0\times 10^{-3}\) \\ III & Silty Clay & 0.5 & 18.0 & 11.0 & 10.0 & \(1.0\times 10^{-6}\) \\ IV & Sandy Silt & 3.70 & 18.5 & 31.5 & 1.0 & \(2.0\times 10^{-3}\) \\ V & Silty Clay & 2.3 & 17.3 & 10.0 & 5.0 & \(2.0\times 10^{-6}\) \\ VI & Fine Sand & 29.5 & 19.0 & 31.5 & 1.0 & \(2\times 10^{-2}\) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Physical and mechanical parameters of each soil layer.