esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Materials and Methods  
### Synthesis of ILs and Materials  
New ILs (i.e., IL1 (1,3-dipropyl-2-(2-propoxyphenyl)-4,5-diphenylimidazolium iodide) and IL2 (1,3-dibutyl-2-(2-butoxyphenyl)-4,5-diphenylimidazolze iodide) were synthesized in the laboratory using  
Figure 1: Chemical structures of new ionic liquids (ILs): (**a**) IL1; (**b**) IL2.  
MAOS (microwave-assisted organic synthesis) method as described by [PERSON] et al. [11]. An amount of 201 mmol of 1-iodopropane was reacted with 2-(2-Hydroxyphenyl)-4,5-diphenylimidazole (67 mmol) to produce IL1 in a reactor, which was mixed with sodium hydride (134 mmol) in tetrahydrofuran (12 mL). The mixture was then stirred in a magnetic stirrer tank for 20 min. Then, the mixture was placed in the CEM (Chemistry, Electrical, Mechanical) microwave reactor set at the temperature of 190 \({}^{\circ}\)C for 1.5 h. IL2 was synthesized similarly to the procedure of the IL1 synthesis with 1-iodobutane as a butyl source in the alkylation process. The synthesis reactions were monitored by thin layer chromatography using ethyl acetate: methanol (3:7 (_v/v_)) as the eluent. The crude product was purified by a liquid-liquid extraction method using _n_-hexane (3 \(\times\) 10 mL). The residue was purified by column chromatography (silica gel as the stationary phase; methanol: _n_-hexane 1:9 (_v/v_) as the mobile phase). The ILs were dried in a vacuum oven for 4 h. The purity of the synthesized IL1 and IL2 were analyzed by FTIR, NMR, HR-ESI-MS and elemental analysis as described by [PERSON] et al. [11]. The equipment used for measuring the corrosion inhibition performance of new ILs was the Potentiostat/Galvanostat PGZ 301 Radiometer. Volta Master 4 software was used to process the measurement data of the corrosion inhibition performance. The NaCl salts used were of reagent grade. The elemental composition of the carbon steel used in this study is shown in Table 1.
## 4 Results and Discussion
### Summary  
#### 4.3.1 Capillary Action (Loading Curve)  
A first conclusion derived from the load curve analysis is that the smaller the pore size, the greater its pumping capacity, regardless of the method of manufacturing the porous medium or wick. All the tested wicks satisfied the minimum advance speed specification (0.031 mm/s), which meant that they all had the capacity to transport higher thermal power. The stainless-steel wire mesh 60 provided the fastest advance speed (Figure 14a), which meant it could transport higher thermal power, thus increasing the performance of the wick.  
As may be observed, the speed of advance of the scaffold 90 (SLM) was 23% faster than for copper sintering 95 (the most widely used manufacturing technique) and 377% slower than for the stainless-steel mesh 60. However, the maximum pumpable height was 63% lower than that of sintered copper 95 (Figure 14b). The maximum height of the stainless-steel mesh 60 was 67% higher than the height of the scaffold and equivalent to the height of the sintered copper 95.  
Figure 13: Comparative test; (a) permeability vs. pore size of copper powder sintering, and (b) permeability vs. meniscus size of scaffold-SLM.  
In view of the results, the behavior of the scaffold was inferior to the behavior of the stainless-steel mesh 60, but superior to that of the sintered copper 95. This result implies that the SLM design was capable of pumping more fluid than the sintering copper 95 and was therefore able to transmit more thermal power. The opposite occurred when compared with the stainless-steel mesh 60. In view of this result, the behavior of the SLM scaffold can be seen as appropriate behavior for use in loop heat pipes.  
As the liquid rose through the wick, the speed of the liquid front decreased and so too did its capillary action, hence the importance of ensuring a wick height that is lower than or equal to the maximum liquid height pumped through it for a good LHP performance. According to the results, although the scaffold provides a similar ascent velocity as the others, the maximum attainable liquid height was lower, which in fact limited its physical height. By modifying the design of the scaffold, the capillarity can be tuned to improve the thermal performance; a very easy operation with SLM technology, creating an \"ad-hoc\" internal structure that maximizes capillarity.  
Figure 14: Comparative test for different techniques with a similar pore size; (**a**) liquid advance speed and (**b**) maximum height of pumping.  
Another key parameter that has a direct impact on LHP performance is its porous media permeability (\(\kappa\)); the higher this value, the lower the LHP internal pressure drop, resulting in a lower pumping need.
# An Attention-Based Method for Remaining Useful Life Prediction of Rotating Machinery
## 3 Model Verification and Comparison
### Experiment Preparation  
The most widely used datasets include the CWRU dataset, the Paderborn dataset, the IMS dataset [22] the FEMTO-ST dataset [23], and the XJTU-SY dataset [24]. Table 1 shows the specifics of these datasets.  
Because the XJTU-SY dataset not only contains the characteristic information of life prediction but also 4 types of fault life data, it contains a total of 15 sets of test data. The RUL prediction method for rotating parts proposed in our work involves three modules: feature extraction, performance state classification, and RUL prediction. Given the requirements for model construction and the specifics of the datasets, the XJTU-SY dataset is more suitable for training and validating models than other datasets.  
The bearings used in our experiments are LDK UER204 rolling bearings with an internal radius of 29.30 mm, an external radius of 39.80 mm, and 8 balls with a diameter of 7.92 mm. The vibration signals of the bearings are sampled by a vertical PCB352C33 acceleration transducer and a DT9837 dynamic signal sampler; sampling is performed at a frequency of 25.6 kHz with a sampling interval of 1 min, and each round of sampling lasts 1.28 s. For the sake of safety, the relative thresholding method is employed to identify the failure threshold of the bearing. Specifically, when the vibration amplitude exceeds \(10\times A_{h}\), the bearing is considered to fail, and the experiment is terminated immediately (\(A_{h}\) is the maximum amplitude of the bearing under normal working conditions). The dataset comprises four types of data--normal working conditions, inner ring damage, outer ring  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Dataset** & **RUL Information** & **Fault Types** & **Test Sets** \\ \hline CWRU & Null & 15 & 60 \\ Paderborn & Available & 2 & 32 \\ IMS & Available & 3 & 3 \\ FEMTO-ST & Available & Unlabeled & 14 \\ XJTU-SY & Available & 4 & 15 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Overview of public datasets on bearings.  
damage, and bearing cage cracks (Figure 6)--and there are 15 sets of testing data, the requirements of our proposed model for calculation better than other datasets.
# Role of Blockchain Technology in Combating COVID-19 Crisis
## 4 Results
### Applications of Blockchain Technology to Fight against COVID-19
#### 4.4.4 Supply Chain Management  
The ongoing pandemic is causing massive damage to the supply chain worldwide as factories have been unable to deal with this shutdown due to the new measures, such as physical contact and social distancing. Therefore, the ban has been applied to importing and exporting the global supply chain [3]. According to [51], \"94% of Fortune 1000 companies are seeing supply chain disruptions from COVID-19\", \"75% of companies have had negative or strongly negative impacts on their businesses\", and \"55% of companies plan to downgrade their growth outlooks\". Medical and pharmaceutical supply chains are hard to find because of the high demand [3]. Furthermore, the supply chains of household needs have also had a high surge in demand [3].  
One of the best options to consider managing the supply chain is blockchain. First, it can connect all of the stakeholders through one decentralized universal network, and by its' property transparency, it securely shows the data of the silos. As mentioned in [36], many blockchain networks in the supply chain management field were mentioned. As mentioned in the previous sections, blockchain technology in any field or application provides quick data handling, reduces processing time, and has a lower risk in its operations. One example that was applied in China is the VeChain platform, assuring the credibility and reliability of masks that were imported from China. It checks codes, materials, packages, and all associated tasks [35; 51].
# Energy Performance of LR-FHSS: Analysis and Evaluation
## 3 Overview of LoRaWAN and LR-FHSS
### LoRa  
LoRa is a PHY radio communication technology that was released in 2009. It employs a modulation technique known as chirp spread spectrum (CSS), which uses frequency-modulated chirps to encode data. This method can accomplish long-distance communications and robustness against interference. In CSS, every symbol is represented by a unique series of chirps. The frequency is swept linearly across a predetermined bandwidth, either upwards or downwards, to produce these chirps. The symbol value determines the initial frequency of each chirp. The key parameters to take into account in LoRa are:  
1. **Bandwidth (BW):** BW is the frequency range that the chirp signal covers. The data rate tends to increase with bandwidth. In the EU region, there are two possible BW values: 250 kHz and 125 kHz.
2. **Spreading factor (SF):** The SF is the quantity of chirps required to represent one symbol. Each symbol is translated into 2\({}^{SF}\) chirps. Bit rate and range are impacted by the SF; larger SFs lead to longer on-air times and lower bit rates, but they also boost sensitivity and range. Particularly, when used in LoRaWAN, the supported LoRa SFs range from 7 to 12.
3. **DR:** DR depends on the combination of distinct SF and BW values. The LoRaWAN Regional Parameters specification defines a range of possible DR values that vary depending on the region [28]. There are eight potential DRs in the EU region, with the DR index ranging from 0 to 7. However, the latter can only be used with FSK modulation. Table 2 summarizes the possible configurations and shows the resulting physical bit rate for each one. For LR-FHSS, which we will address in Section 3.3, DRs 8 to 11 were added.
4. **Coding rate (CR):** In order to prevent bit corruption, forward error correction (FEC) is used, with different possible CR values being between 0 and 4. These correspond to  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**DR** & **M (bytes)** & **N (bytes)** \\ \hline
0 & 59 & 51 \\ \hline
1 & 59 & 51 \\ \hline
2 & 59 & 51 \\ \hline
3 & 123 & 115 \\ \hline
4 & 250 & 242 \\ \hline
5 & 250 & 242 \\ \hline
6 & 250 & 242 \\ \hline
7 & 250 & 242 \\ \hline
8 & 58 & 50 \\ \hline
9 & 123 & 115 \\ \hline
10 & 58 & 50 \\ \hline
11 & 123 & 115 \\ \hline
12–15 & Not Defined & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Maximum MAC payload sizes for LoRaWAN in column M and maximum application PDU size (FRM Payload) in column N for each DR and without FOpts field.  
coding rates from 4/5 to 4/8, with CR = 0 (or coding rate 4/5) being the default value. For LR-FHSS, coding rate values 1/3 and 2/3 have been introduced.  
The LoRaWAN specification also defines support for the adaptive data rate (ADR) mechanism, which allows the NS to evaluate the link quality and adapt the EDs to the channel conditions for optimal performance by modifying the DR, transmission power, and maximum number of retransmissions as appropriate.
# Quantitative Description for Sand Void Fabric with the Principle of Stereology
## 4 Novel Void Fabric Tensors Definitions
### Orthotropic Void Fabrics  
The void amplitude parameter (\(b_{1}\), \(b_{2}\) and \(b_{3}\)) obtained by Equations (14)-(16) in 2D space is not equal to the principal value (\(M_{1}\), \(M_{2}\) and \(M_{3}\)) in 3D space, but proportional to it. Therefore, the following void fabric equation is established and reads:  
\[M_{ij}=\left[\begin{array}{ccc}M_{1}&0&0\\ 0&M_{2}&0\\ 0&0&M_{3}\end{array}\right] \tag{18}\]  
According to \(M_{kk}=1\) and any two parameters from \(b_{1}\), \(b_{2}\), and \(b_{3}\), the orthotropic fabric tensor is obtained, and the detailed derivative process is shown in reference [31]. The three equations of orthotropic fabric tensor are as follows:  
\[\begin{array}{l}M_{1}=\frac{(1+b_{1})(1+b_{2})}{3+b_{1}+b_{2}-b_{3}b_{3}}\\ M_{2}=\frac{(1+b_{1})(1-b_{2})}{3+b_{1}+b_{2}-b_{1}b_{2}}\\ M_{3}=\frac{(1-b_{1})(1+b_{2})}{3+b_{1}+b_{2}-b_{1}b_{2}}\end{array} \tag{19}\]  
\[\begin{array}{l}M_{1}=\frac{(1+b_{1})(1-b_{3})}{3-b_{1}-b_{3}-b_{3}b_{3}}\\ M_{2}=\frac{(1-b_{1})(1-b_{3})}{3-b_{1}-b_{3}-b_{3}b_{3}}\\ M_{3}=\frac{(1-b_{1})(1-b_{3})}{3-b_{3}-b_{3}-b_{3}b_{3}}\end{array} \tag{20}\]  
\[\begin{array}{l}M_{1}=\frac{(1+b_{2})(1+b_{3})}{3-b_{2}+b_{3}+b_{2}b_{3}}\\ M_{2}=\frac{(1-b_{2})(1+b_{3})}{3-b_{1}+b_{2}+b_{3}b_{3}}\\ M_{3}=\frac{(1+b_{2})(1-b_{3})}{3-b_{2}+b_{3}+b_{2}b_{3}}\end{array} \tag{21}\]  
Equation (19) is the three principal value parameters \(M_{1}\), \(M_{2}\) and \(M_{3}\) of the orthotropic void fabric tensor, which are calculated by the void amplitude parameters \(b_{1}\) and \(b_{2}\) of the surface \(x_{1}\)-\(x_{3}\) and surface \(x_{1}\)-\(x_{2}\). Similarly, Equation (20) is the three principal value parameters \(M_{1}\), \(M_{2}\) and \(M_{3}\) of the orthotropic void fabric tensor, which are calculated by the void amplitude parameters \(b_{1}\) and \(b_{3}\) of the surface \(x_{2}\)-\(x_{3}\). Equation (21) is the three principal value parameters \(M_{1}\), \(M_{2}\) and \(M_{3}\) of the orthotropic void fabric tensor, which are calculated by the void amplitude parameters \(b_{2}\) and \(b_{3}\) of the surface \(x_{1}\)-\(x_{2}\) and surface \(x_{2}\)-\(x_{3}\).  
Therefore, as long as any two void invariants of the three orthogonal planes are obtained through experiments, the orthogonal anisotropic fabric is determined by Equation (18). Equations (19)-(21) not only provided more options for the theoretical description of \(M_{ij}\) but also provided more flexible methods for the orthotropic experimental measurement of void fabric for sand.
# Monocular Vision Guidance for Unmanned Surface Vehicle Recovery
## 2 Materials and Methods
### Visual Localization of the USV
#### 2.4.2 Visual Localization Process
complementary angle to the angle between the \(Z\)-axis of the camera coordinate system and the \(Z\)-axis of the world coordinate system, as shown in Figure 8. In Figure 8, \(Z_{c}\) and \(Z_{w}\) represent the \(Z\)-axes of the camera coordinate system and the world coordinate system, respectively, while the plane labeled \(k\) represents the artificial marker plane, which corresponds to the \(X_{w}O_{w}Y_{w}\) plane of the world coordinate system. In this study, we use vector methods to calculate the angle \(\alpha\) between these two \(Z\)-axes and then determine the complement angle of this angle to obtain the desired angle \(\beta\). The specific procedure for calculating the angle is as follows:  
Firstly, the third column of the rotation matrix \(R\) is considered the representation of the \(Z\)-axis of the camera coordinate system in the world coordinate system, as shown in Formula (15). \[A=R_{3}=(R_{13},R_{23},R_{33}) \tag{15}\]  
Next, by transposing the rotation matrix \(R\), the vector representation of the \(Z\)-axis of the world coordinate system in the camera coordinate system can be obtained. This is achieved by calculating the transpose matrix \(R^{T}\) of \(R\) and taking its third column as the vector representation of the \(Z\)-axis of the world coordinate system in the camera coordinate system, as shown in Formula (16). \[B={R^{T}}_{3}=(R_{31},R_{32},R_{33}) \tag{16}\]  
Then, the angle \(\alpha\) between the camera coordinate system and the world coordinate system can be obtained by using the two vectors, as shown in Formula (17). \[\alpha=\arccos(\frac{R^{T}_{3}\times R_{3}}{|R^{T}_{3}|\times|R_{3}|}) \tag{17}\]  
Finally, by taking the complement of \(\alpha\), the angle \(\beta\) between the optical axis and the artificial marker plane can be obtained, as shown in Formula (18). \[\beta=\frac{\pi}{2}-\alpha \tag{18}\]
# Victim Detection and Localization in Emergencies
## 9 Conclusions  
People usually typically have a smartphone on them, and in the case of a disaster, such as an earthquake, these devices could be very helpful for finding individuals. Drones are terrain independent and can easily approach a victim's location. The integration of WiFi FTM and UWB with the drones could be crucial for first responder activities to detect victims under rubble. Despite the fact that WiFi presented better results with regard to the accuracy, coverage, and penetration capabilities, as shown in Figure 4, it is worth implementing both UWB and WiFi technologies to improve the inputs to the localization algorithm. Future lines of work are to implement more radio technologies such as BLE or cellular 4/5G due to their multiple advantages: to augment the coverage and probability of detecting and localizing victims, to have higher accuracy in the localization process, and to implement a new protocol that is more stable and faster between the first responder services and the drones. In addition, in the scope of this work, another future goal is to reproduce the experiment in a realistic emergency scenario in a bigger deployment with more realistic damaged infrastructure and the participation of first responders, such as in training installations. Moreover, a study of the integration of a real prototype within the rescue protocols of the first responders may be carried out.  
Conceptualization, C.S.A.-M., H.Q.L.-C. and E.J.K.; methodology, C.S.A.-M. and H.Q.L.-C.; software, C.S.A.-M.; validation, C.S.A.-M. and H.Q.L.-C.; formal analysis, C.S.A.-M., H.Q.L.-C. and E.J.K.; investigation, C.S.A.-M., H.Q.L.-C. and E.J.K.; writing--original draft preparation, C.S.A.M.; writing--review and editing, C.S.A.-M., E.J.K. and R.B.; visualization, C.S.A.-M.; supervision, R.B.; funding acquisition, R.B. All authors have read and agreed to the published version of the manuscript.  
This work was performed in the framework of the Horizon 2020 project LOCUS (Grant Agreement Number 871249), receiving funds from the European Union. This work was also partially funded by Junta de Andalucia (Project PY18-464?:PENTA).  
**Data Availability Statement:** Not applicable.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# Pixel Circuit Designs for Active Matrix Displays
## 1 Introduction
### TFT Devices
#### 1.3.5 Double-Gate TFT  
The performance of TFTs described in previous sections is based on single-gate (SG) TFTs. Double-gate TFTs (DG TFTs) consist of two opposing gates (Figure 3). In 1981, [PERSON] et al. first developed DG TFTs using CdSe as an active layer for flat panel display applications [49]. In DG TFTs, two parallel channels emerge when voltages are applied to the top and bottom gate electrodes. DG TFTs can flexibly adjust the position of the channel and the carrier transport path, which significantly mitigates the effect of material defects [50]. This improves carrier mobility and reduces the subthreshold slope (SS) [50; 51]. SS is the slope of the relationship between gate voltage and drain current. A small SS indicates high switching speed and precise controllability of the TFT device [52]. Moreover, due to the effective active layer width, DG TFTs have a greater drive current than SG TFTs. Therefore, DG TFTs can be applied to displays with high frame rates. Another advantage of DG TFTs is their on-state voltage controllability, where the \(V_{\text{TH}}\) can be adjusted as a function of the applied top gate bias voltage, determined by the capacitance ratio of the two gate dielectrics [53]. This characteristic serves to support the adaptability of circuit design.  
Figure 3: DG TFT device structure [54].  
Figure 2: IGZO and LTPS TFT array technology with a metal barrier layer [48].
## 2 Materials and Methods
### Error Budget Approach
#### 2.3.2 Systematic Errors  
Systematic errors are induced by our limited knowledge on the system parameters and measurement conditions; in particular, we take into account the simple case of a dominant perturbation on the telescope EFL, affecting the optical scale \(s=1/F\), which translates the actual focal plane estimate of image separation in pixels into the corresponding angular value on the sky. The effect of optical scale variations is a change in the estimated separation between stars, which is directly related to the mission goal, i.e., the determination of the light deflection induced by gravity.  
A different source of systematic error is the limited knowledge of actual star parameters within the observed sample. Star positions and parallaxes are affected by uncertainties, which are explicitly listed in the Gaia DR3 (and future DR4) catalog. The GLADE measurement of deflected star positions is therefore jeopardized by both contributions, directly by the former and indirectly by the latter. The relationship between variations in the light deflection effect, namely a change \(\delta\gamma\) (in \(10^{-5}\) units) of the \(\gamma\) PPN parameter, and the shift \(\delta\sigma\) (in \(\mathrm{\SIUnitSymbolMicro\second}\)s) induced in stellar parallaxes [33] (Equation (12) therein) occurs in the case of Gaia (averages on the sky):  
\[\frac{\delta\sigma\,\left[\mathrm{\SIUnitSymbolMicro\second}\right]}{\delta \gamma\,\left[10^{-5}\right]}\simeq-\frac{1}{35}\,. \tag{3}\]  
Hence, errors on parallaxes could potentially affect the estimate of \(\gamma\). The origin of the effect may be better perceived by the consideration that it corresponds to a displacement of star images depending on their angular separation from the Sun and distance from the observer, and both factors also relate to light deflection.  
This relation between the systematic errors is a direct consequence of Gaia's very specific observational geometry, when variations in the trigonometric parallaxes and PPN gamma have very similar impacts on observables. It is worth emphasizing that no such kind of systematic error can appear in the GLADE experiment because the parallactic and light deflection effects are completely decoupled. Indeed, the parallactic displacement is toward the Solar System's barycenter, while the deflection effect is directed toward the Sun's center. The angle between these directions can be up to 45 degrees if an object is observed one degree from the Sun.
# Design of Power Splitters Based on Hybrid Plasmonic Waveguides
###### Abstract  
Plasmonic power splitters based on hybrid plasmonic waveguides (HPWs) are proposed and investigated. The HPW consists of a high-permittivity semiconductor nanowire embedded in a SiO\({}_{2}\) dielectric film near a metal surface. The propagation behaviors of Surface Plasmon Polaritons (SPPs) in HPWs are numerically simulated by the 3D finite-difference time-domain (FDTD) method. The incident field is transferred from the middle waveguide to the waveguides on both sides due to the coupling between adjacent waveguides. The intensity distributions can be explained by the multimode interference of SPPs supermodes. According to the field intensity distribution of five HPWs, we design a \(1\times 3\) power splitter and a \(1\times 2\) power splitter by reducing the length of some specific waveguides.  
power splitters; surface plasmon polaritons; hybrid plasmonic waveguides +
Footnote †: journal: Applied Physics Letters  
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