esa-sceva/satcom-chunk-collection huggingface dataset:
# Determination of Cellulose Degree of Polymerization in Historical Papers with High Lignin Content
## 1 Introduction
The two most likely reactions during acid-chlorite delignification are acid hydrolysis of glycosidic bonds and oxidative degradation of polysaccharides [21]; generally, acetic acid is added to the delignification procedure to lower the pH. However, the addition of acetic acid increases the probability of degradation by acid hydrolysis. The presence of lignin in cellulose samples minimized the average DP\({}_{\rm v}\) reduction of cellulose due to acid-catalyzed cleavage during acid-chloride delignification [19]. In the study by [PERSON] et al. [22], acid-chlorite treatment was shown not to induce degradation under room temperature conditions even in bleached Kraft pulps from eucalyptus. In contrast, [PERSON] et al. [23] demonstrated that delignification of switchgrass and poplar solids under high doses of NaClO\({}_{2}\) and acetic acid removed significant amounts of carbohydrates and total solids in addition to lignin and that the treatment had a significant effect on cellulose M\({}_{\rm w}\). The differences in the results of the studies cited above can most likely be explained by different conditions and the different ratios of NaClO\({}_{2}\), acetic acid, and paper during delignification. The main components of paper are polysaccharides. Based on quantitative results of monosaccharides in 18 th- and 19 th-century paper documents determined by HPLC, these papers contained the highest amount of glucose and very small amounts of other hemicellulose components (galactose, mannose, and arabinose and no xylose). The papers from the second half of the 19 th to the 21 st century contained lower amounts of glucose and up to 16% of other monosaccharides (galactose, mannose, arabinose, and xylose) [24]. Therefore, another parameter to evaluate in the depolymerization of polysaccharides may be the amount of monosaccharides (glucose, mannose, galactose, xylose and arabinose) released during depolymerization. For the determination of small amounts of monosaccharides, ion chromatography is the method of choice [21]. The aim of this study was to evaluate the viscometric method using CED to determine the degree of polymerization in various historical groundwood-containing papers after acid-chlorite delignification. The suitability of SEC UV-VIS analysis for determination of M\({}_{\rm w}\) of CTC in papers containing high lignin content had been verified before it was used as a comparative method to viscometry. Several paper samples from the books with high content of groundwood fibers were delignified according to the procedure of [PERSON] [12]. Lignin removal was followed by the determination of Kappa number, and cellulose degradation was followed by SEC analyses where weight average molecular masses for cellulose tricarbanilate (CTC) derivatives were determined according to the method proposed by [PERSON] et al. [25]. Monosaccharides were determined in filtrates of the different stages of delignification by ion chromatography to additionally evaluate cellulose degradation.
## 3 Results and Discussion  
### Impact of Pore Size in Intermediate Layers  
Asymmetric membranes consist of various layers, including a membrane layer, intermediate layers, and a support that enhances the mechanical stability of the upper layers. More details about the substrate can be found elsewhere [32]. The pore size of the intermediate layer significantly affects the diffusion process of the membrane, as the thin top layers must be uniformly formed on it without defects (Figure 1a). Regarding this parameter, alumina supports with pore sizes of 100 nm, 200 nm, 800 nm, and 3 \(\upmu\)m were used as intermediate layers. These membranes were fabricated under identical conditions, and based on the outcomes in Figure 1b, it is noticeable that the intermediate layers with size of 800 nm and 3 \(\upmu\)m display high N\({}_{2}\) permeance (1.31 \(\times\) 10\({}^{-5}\) and 7.28 \(\times\) 10\({}^{-5}\) [mol/(m\({}^{2}\)sPa)], individually), from which it can be inferred that the membrane layer exhibits incomplete coverage across the surface due to the presence of intercrystalline gaps. Thus, these gaps provide insufficient nucleation sites for the formation of a compact and homogenous SSZ-13 layer and permit N\({}_{2}\) molecules to penetrate through flaws and non-zeolithic pathways. Furthermore, an increase in the intermediate layer pore size leads to a thicker membrane due to enhanced capillary filtration. This increase in layer thickness increases the possibility of structural defects in the membrane even before the calcination process [20,21]. Nevertheless, the N\({}_{2}\) permeance for intermediate layers of 100 and 200 nm decreases to 4.96 \(\times\) 10\({}^{-7}\) and 1.24 \(\times\) 10\({}^{-9}\) [mol/(m\({}^{2}\)sPa)], respectively. The support with a pore size of 100 nm has defects (non-zeolitic pores, because seed adhesion and penetration were not sufficient to penetrate the surface) that affect membrane efficiency. Based on the outcomes, intermediate layers with pore sizes of 200 nm formed a tight layer and were selected for further investigations.
# Study on EEMD-Based KICA and Its Application in Fault-Feature Extraction of Rotating Machinery
## 4 Application and Validation
### Experimental Analysis of Faulty Gear
#### 4.1.1 Wavelets  
In this method, the collected signal is decomposed with five-layer Daubechies wavelet decomposition first, and then the amplitude spectra of each component can be obtained with FFT. The result in Figure 4 shows that the rotation frequency \(f_{r}\) and its frequency multiplication are not extracted, and the frequency \(f_{z}\) is also not extracted. Therefore, wavelets cannot extract the fault feature of a broken tooth.
# Nonlinear Blind Source Separation and Fault Feature Extraction Method for Mining Machine Diagnosis
###### Abstract  
Mining machines are strongly nonlinear systems, and their transmission vibration signals are nonlinear mixtures of different kinds of vibration sources. In addition, vibration signals measured by the accelerometer are contaminated by noise. As a result, it is inefficient and ineffective for the blind source separation (BSS) algorithm to separate the critical independent sources associated with the transmission fault vibrations. For this reason, a new method based on wavelet de-noising and nonlinear independent component analysis (ICA) is presented in this paper to tackle the nonlinear BSS problem with additive noise. The wavelet de-noising approach was first employed to eliminate the influence of the additive noise in the BSS procedure. Then, the radial basis function (RBF) neural network combined with the linear ICA was applied to the de-noised vibration signals. Vibration sources involved with the machine faults were separated. Subsequently, wavelet package decomposition (WPD) was used to extract distinct fault features from the source signals. Lastly, an RBF classifier was used to recognize the fault patterns. Field data acquired from a mining machine was used to evaluate and validate the proposed diagnostic method. The experimental analysis results show that critical fault vibration source component can be separated by the proposed method, and the fault detection rate is superior to the linear ICA based approaches.  
m _Applied_  
_sciences_
# Large-Scale Automatic Vessel Monitoring Based on Dual-Polarization Sentinel-1 and AIS Data
## 3 Results
### Mexico Test Case  
Figure 7 presents the qualitative cross comparison of the AIS positions and SAR-based detections for the Mexico test case. We notice that with respect the English Channel case study, the traffic in  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Case Study** & **AIS \(\cap\) SAR** & **AIS with no SAR** & **SAR with no AIS** & **AIS \(\cup\) SAR** \\ \hline English Channel & nb. of vessels & 998 & 393 & 713 & 2104 \\ Mexico & & 51 & 0 & 12 & 63 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Automatic identification system (AIS) and SAR cross-comparison, SAR detections derived by using the proposed dual-polarization algorithm.  
Figure 6: Statistical analysis of the detection performances derived for 1400 vessels extracted from 10 SAR images and the corresponding AIS data flow: (**a**) AIS vessel length distribution; (**b**) probability of detection as a function of polarization and vessel length.  
the Mexican open sea areas was characterized by a lower number of vessels. The total number of interpolated AIS messages for this case study was equal to 60, including mostly large sized vessels and a few small-sized ones. The overall size of the small vessels belonging to this dataset was 30 m and the corresponding types are tug and sailing vessels. Therefore, hypothetically speaking, all the AIS vessels corresponding to this dataset could be also detected in the SAR images, since their sizes were larger than the Sentinel-1 IW SLC spatial resolution. The hypothesis is proven by the experimental results: all the AIS vessels presenting a match in the SAR-based detections are depicted in Figure 7 (SAR detection rate = 100%). As illustrated in Figure 7, the Mexico dataset overall presents a high agreement between the AIS and SAR positions that corresponds mainly to large sized vessels navigating towards the Panama Channel. Table 2 presents the number of AIS and SAR targets issued from their cross-comparison. We can notice that the percentage of SAR detections with no corresponding AIS positions was lower than for the English Channel case study. In addition, we have made a visual inspection confirming that the 12 vessels detected by the coherence (over-detections) were in fact no false alarms but correspond to dark vessels or vessels that were not required to carry an AIS transponder. In the following section, different cases illustrating the vessel signatures of SAR unmatched targets are presented in order to have a better understanding of the global rate of the SAR detections.
# Design of Power Splitters Based on Hybrid Plasmonic Waveguides
## 1 Introduction  
Surface Plasmon Polariton (SPP) waveguides can break the diffraction limitation and are regarded as the best candidate to design miniaturized photonic integrated circuits [1, 2]. All kinds of plasmonic waveguides have been designed, such as the dielectric loaded metal, metal wedges, slot and gap waveguides, and hybrid plasmonic waveguides [3, 4]. Among these plasmonic waveguides, the hybrid plasmonic waveguide (HPW) is one of the most promising alternatives for on-chip nanophotonics due to the ability of subwavelength confinement and long propagation lengths [3].  
In photonic integrated circuits, a power splitter is an essential component, which can distribute the energy of incident light to different propagation directions. Various plasmonic power splitters have been proposed, such as \(1\times 2\) splitters [5, 6, 7, 8], \(1\times 3\) splitters [9], \(1\times \mathrm{N}\) splitters [10, 11, 12], and variable transmission splitters [13, 14, 15]. The overwhelming majority of these plasmonic splitters are designed on the basis of metal-insulator-metal (MIM) waveguides, which are composed of two metallic layers and a dielectric layer [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]. However, there are few researches on the power splitter based on HPWs. The main reason is that an MIM waveguide could be simplified to a two-dimensional structure and a HPW cannot be simplified to a two-dimensional structure, of which the computational complexity of a 3D structure is much larger than that of a 2D structure. Due to the excellent performance of the HPWs, it is necessary to design a 3D power splitter based on HPWs for the next generation of integrated photonic circuits.  
In this paper, we present several new power splitters based on hybrid plasmonic waveguides. The propagation behaviors of Surface Plasmon Polaritons (SPPs) in HPWs are numerically simulated by the 3D finite-difference time-domain (FDTD) method. According to the field distribution of five HPWs, we reduce the length of some specific waveguides and design different types of power splitters. The power splitters based on HPWs arefully compatible with semiconductor fabrication techniques and can be widely used in integrated photonics structures.
# Active Tunable Elastic Metasurface for Abnormal Flexural Wave Transmission
## 2 Mechanisms of Actively Tunable Elastic Metasurface
### Derivations of the Governing Equation
Therefore, the relationship between the external control voltage \(Y_{\rm a}\) and the sensing voltage \(Y_{\rm s}\) can be expressed as  
\[Y_{\rm a}=-gY_{\rm s}=g\frac{d_{31}I_{1}}{\varepsilon_{33}w_{1}}\frac{ \partial^{2}w}{\partial x^{2}} \tag{7}\]  
where \(g\) is the proportional feedback control gain of the piezoelectric actuator. The active stiffness can be generated by an external control voltage applied to the piezoelectric actuator, which can manipulate the flexural wave propagation characteristics of the adaptive unit cell. The variation in \(g\) is also limited to 0-100 in order to maintain the stability of the constant voltage electric field. Substituting Equations (6) and (7) into Equation (5), the coupled equation can be obtained as  
\[D_{\rm a1}\frac{\partial^{4}w(x,t)}{\partial x^{4}}+\rho_{\rm a}h\frac{ \partial^{2}w(x,t)}{\partial t^{2}}=0 \tag{8}\]  
where \(D_{\rm a1}\) is the equivalent stiffness of the beam with the piezoelectric actuator and sensor acting together and can be written as  
\[D_{\rm a1}=D_{\rm a}+(1+g)\frac{d_{31}^{2}I_{1}^{2}}{\varepsilon_{33}w_{1}h_{ \rm p}} \tag{9}\]  
The separable solution to Equation (8) can be written as \(w(x,t)=w(x)\mathrm{e}^{\mathrm{i}\omega t}\), where \(\omega\) is \(2\pi f\). Substituting this solution and Equation (9) into Equation (8), the control equation for the flexural wave can be obtained as  
\[\frac{\partial^{4}w(x)}{\partial x^{4}}-k^{4}\frac{\partial^{2}w(x)}{\partial t ^{2}}=0 \tag{10}\]where \(k\) is the wavenumber and \(k^{4}\) is expressed as  
\[k^{4}=\frac{\rho_{\mathrm{a}}h\omega^{2}}{D_{\mathrm{a1}}} \tag{11}\]  
The phase velocity \(c\) for the flexural wave is  
\[\rho_{\rm a}=\rho_{\rm s}h_{\rm s}+2\rho_{\rm p}h_{\rm p} \tag{3}\]0  
Equation (12) indicates that flexural waves are dispersive, and their phase velocity depends on the flexural stiffness. In designing the metasurface, we can vary the magnitude of the gain using a negative proportional feedback control system to obtain the desired phase velocity.
## 5 Conclusions  
In this paper, a number of theoretical analyses and numerical experiments were conducted to find a better method to solve centralized multi-satellite scheduling problems.  
Firstly, considering the load and platform operation of satellites in reality, we established a mathematical model of satellite scheduling with complex constraints, and the related mathematical statement was given.  
Secondly, the real-coding Population-Based Incremental Learning (PBIL) algorithm was proposed to solve the MSSP. Compared to the traditional PBIL algorithm with binary coding, the real-coding format can greatly shorten the coding length so that the computational efficiency is improved. Additionally, we designed the value probability matrix, correction coefficient and mutation operator to guide better evolution and avoid early convergence.  
Furthermore, some numerical simulations and analyses were conducted to verify the real-coding PBIL algorithm for multi-satellite scheduling. Additionally, we analyzed the influence of key parameters such as the probability correction coefficient on algorithm performance. The performance of the algorithm was analyzed by comparing it with binary-coding PBIL and Genetic Algorithm (GA). According to the numerical results, it can be seen that when solving multi-satellite scheduling problems, in terms of the algorithm efficiency, solution quality and task completion rate, the real-coding PBIL algorithm is superior to other algorithms in our study.
# Classification of Tropical Cyclone Tracks in the Northwest Pacific Based on the SD-K-Means Model
## 4 Results Analysis
### TC Landing Situations  
Although TCs will continue to affect surrounding areas during their movement and thus cause losses to coastal areas, the damage they cause to the landing point and its surrounding areas when they land is particularly huge. Therefore, this section visualizes the annual landing situations of various TCs [28; 29]. The specific landing statistics are shown in Figure 8.  
Figure 7: Average seasonal distribution of TC activity: (**a**) represents the overall average seasonal distribution of all TC activity; (**b**) represents the relative average seasonal distribution of each type of TC activity.  
As can be seen from Figure 8, in the 23 years from 2000 to 2022, Cluster 0 consistently exhibits the highest proportion of landfalling TCs, accounting for the majority in over 72.7% of the years. According to Figure 3, these TCs primarily make landfall in the eastern coastal provinces of China. In the remaining years, Cluster 3 accounts for the most landfalling TCs, primarily affecting southeastern coastal regions such as Hainan and Guangdong Provinces. Clusters 1 and 2 contribute relatively fewer landfalling TCs, and their impacts are mainly confined to the Korean Peninsula and Japan.  
To further illustrate landfall behavior, the yearly distribution of TC genesis locations in each cluster is shown in Figure 9. Notably, from 2016 to 2021, only Cluster 3 TCs made landfall, consistent with the simplified bar chart pattern seen during this period in Figure 8.  
A provincial breakdown of landfall occurrences in China is provided in Table 4. The results confirm that southeastern coastal regions--specifically Guangdong, Taiwan, Fujian, and Hainan Provinces--are most frequently impacted by landfalling TCs. In contrast, northeastern regions experience fewer landfalls. Most landfalling TCs fall under Clusters 0 and 3, which is consistent with earlier observations.
## 3 Computational Setup  
The study by [PERSON] et al. [1] defines the reference case. In this setup, a NACA0012 airfoil with a chord length of 100 mm and span of 300 mm is used, and a rod is placed at one chord upstream of the airfoil. Two rod diameters, namely 0.01 m and 0.016 m, and four inflow speeds, 30.5, 61, 72, and 115 m/s are experimentally studied. Detailed results are supplied for d = 10 mm and u = 72 m/s (M = 0.21) by the authors; hence, these values are also used for this work for the LES/CAA simulations. The inlet Mach number is \(M\) = 0.21, which corresponds to the inlet speed of \(U_{\infty}\) = 72 m/s, and the Reynolds number based on the rod and airfoil chord is \(Re_{d}\) = 48,000 and \(Re_{c}\) = 480,000. Solid surfaces are treated with no-slip boundary conditions, while periodic boundary conditions are imposed in the spanwise direction. The time step size satisfies the Courant number CFL = 1 condition. The spanwise extent of the computational domain is \(L_{s}=0.15c\). The computational domain extends in the streamwise and normal directions, approximately 100\(d\) rod diameters, as presented in Figure 1.  
For the LES/CAA simulations, the coupled FV/DG solver of m-AIA is employed. As mentioned before, the source term used for the CAA simulations is the perturbed lambda vector, which is calculated by using instantaneous and mean parameters. Instantaneous flow parameters are calculated in the coupled simulation at the same time when it is required by the CAA solver, and the mean values are gathered from the mean output file which is obtained by sampling data for a period of time.
## 2 Data Collection and Quality Evaluation
### TH-2 Satellite Formation System  
The TH-2 satellite system was developed by the Shanghai Academy of Spaceflight Technology and launched by the Taiyuan Satellite Launch Center on 30 April 2019 [27]. They travel in a solar-synchronous orbit at \(\approx\)518 km altitude and the incidence angle ranges from 35\({}^{\circ}\) to 46\({}^{\circ}\), separated from each other only a few hundred meters in space [28]. TH-2A and TH-2B carried a multi-GNSS receiver, which can be used for POD and PROD. The onboard GNSS data include GPS L1 and L2 frequencies data, and BDS2 B1 and B3 frequencies data. This study analyzes the onboard GNSS observations of TH-2 during day of year (DOY) 305-332 in 2019, with an interval of 10 s. The days (DOY 323) when both TH-2A and TH-2B performed maneuvers is excluded from the analysis. Taking the GNSS observations of TH-2A as an example for analysis in this section, the result of TH-2B was similar to that of TH-2A.
# A Photonically-Excited Leaky-Wave Antenna Array at E-Band for 1-D Beam Steering
In particular, the case where the proposed antenna is used for automatic alignment in line-of-sight (LoS) mm-wave links will be discussed in more detail here. The realized design features a fairly broad relative bandwidth (\(>\)10%), and allows a scanning range of 22\({}^{\circ}\), including broadside. Moreover, the scalability of the presented layout is beneficial with respect to classical mm-wave antennas to combine several emitters and increase emitted power and or directivity. Section 2 describes the design of the antenna. The integration of the photodiode chip with the PCB is discussed in Section 3. Sections 4 and 5 present measurement results and a potential application, respectively. Finally, conclusions are presented in Section 6.
# A Study on the Feasibility of Natural Frequency-Based Crack Detection
## 5 Numerical Examples and Discussion
### Cracked Plates Made of Ductile Metals
This conservativeness essentially benefits the early crack detection based on natural frequency measurement because it means the ductile fracture occurs even later than what is indicated by the critical crack length and a more severe crack can be tolerated. This means the potential for the application of natural frequency-based crack detection may be better than predicted in this study, because there is a sufficient margin of safety where the crack can exhibit its impact on the frequency domain. It should be noted that based on the limited crack scenarios discussed in this study, it is impossible to reach a general conclusion in terms of the minimum detectable crack length or under what circumstances crack detection based on natural frequency measurement would surely work without failure. However, the results in this study quantitatively show the 'chronological order' between the critical crack severity leading to fracture and the crack severity resulting in a measurable frequency drop. If the former severity is reached before the latter, natural frequency-based crack detection would be risky. If, on the other hand, the crack already causes measurable frequency drops in the first few modes before it jeopardizes the safety of the structural component, then there may be some safety margin where natural frequency-based crack detection can be applied and timely measures for structural maintenance can be taken. It is interesting to see the change in critical crack length and in the ensuing frequency drop when the employed metal varies. This observation implies that the brittleness of the metal plays a vital role in natural frequency-based crack detection. It is possible that natural frequency-based crack detection is more applicable to structural components made of common ductile metals than those high-strength structural components made of brittle metals.