esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Conclusions  
A novel approach was employed to synthesize a nanogold composite (NGC) by combining polyethylene terephthalate (PET) nanofibers with Au\({}^{\text{o}}\)@PPh\({}_{2}\)-PIILP. This groundbreaking research marks the first successful integration of these materials, resulting in a highly efficient NGC for the removal of methylene blue (MB) from wastewater.  
Through the study, the optimal conditions for MB dye removal were determined to be a pH of eight, an adsorbent dosage of 0.006 g, an initial MB concentration of 10 mg L\({}^{-1}\), and a treatment time of 80 min. The adsorption process followed a pseudo-second-order kinetic model, providing a comprehensive description. Additionally, there was a strong agreement between the calculated adsorption capacity (\(q_{e}\))\({}_{cal}\). (4.3840) and the experimental adsorption capacity (\(q_{e}\))\({}_{exp.}\) (4.6838). The Langmuir isotherm also demonstrated a good fit to the data, indicating a maximum adsorption capacity of 18.622 mg g\({}^{-1}\) for MB. The sole constraint in this study lies in the utilization of gold and its costly nature. Therefore, we urge researchers to explore alternative elements that offer comparable effectiveness at a more affordable cost for the elimination of methylene blue.  
\begin{table}
\begin{tabular}{l c c c c} \hline \multicolumn{1}{c}{**Adsorbent Material**} & \(Q_{m}\) & **Time** & **pH** & **[Ref.]** \\ \hline Cellulose nanostructure & 4.369 & 120 min & 6.0 & [49] \\ PET-NF/MWCNTs & 7.047 & 120 min & 8.0 & [19] \\ Modified PET-NF & 13.774 & 100 min & 6.0 & [37] \\ Nanogold composite NGC & 18.622 & 80 min & 8.0 & This study \\ Cu0 NPs & 26.73 & 120 min & 8.0 & [15] \\ Fe\({}_{3}\)O\({}_{4}\) @MIL-100(Fe) & 49 & 400 min & 2.0 & [66] \\ Nanoparticles of microalgae & 58.820 & 180 min & 6.0 & [67] \\ \hline \end{tabular}
\end{table}
Table 3: A comparative analysis of the adsorption capacities \(Q_{m}\) for various types of adsorbents used in previous studies to remove MB.  
**Author Contributions:** Conceptualization, S.A.Y. and E.A.A.; methodology, S.A.Y. and W.K.E.; software, A.A.; validation, E.A.A., S.A.Y. and W.K.E.; formal analysis, S.A.Y. and E.A.A.; investigation, W.K.E. and A.A.; resources, A.A.; data curation, W.K.E. and A.A.; writing--original draft preparation, W.K.E. and S.A.Y.; writing--review and editing, W.K.E. and A.A.A.; visualization, S.A.Y. and E.A.A.; supervision, S.A.Y. All authors have read and agreed to the published version of the manuscript.  
**Funding:** The authors are thankful for the financial support provided by the USAID Partnerships for Enhanced Engagement in Research (PEER) Program (PEER/Iraq project/cycle 6).  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available in the article.  
**Acknowledgments:** The authors are thankful for the USAID Partnerships for Enhanced Engagement in Research (PEER) laboratory for supporting this work at the University of Duhok.  
**Conflicts of Interest:** The authors declare no conflicts of interest.
# Graphene-Based Flexible Electrode for Electrocardiogram Signal Monitoring
## 2 Research on Graphene-Based Flexible ECG Electrodes
### Bionic Graphene ECG Electrodes  
Inspired by nature, many bionic flexible devices for different applications have been developed, such as electronic skin [32], wearable sensors [33], and flexible electrodes [34]. By mimicking human and biological structures, a variety of ECG electrodes with excellent performance, including better skin adhesion, low skin contact impedance, and high stability, have been proposed [35; 36; 37; 38; 39]. In this section, we introduce several typical biomimetic graphene ECG electrodes that have been developed in recent years and discuss their performance characteristics.
## 4 Stability Analysis  
Define the errors \(\Phi_{u}\) and \(\Phi_{r}\)  
\[\left\{ \begin{array}{l}\Phi_{u}=\beta_{u}-\alpha_{u}\\ \Phi_{r}=\beta_{r}-\chi\end{array} \right. \tag{34}\]  
The time derivative of \(\Phi_{u}\) is  
\[\dot{\Phi}_{u} =\dot{\beta}_{u}-\dot{\alpha}_{u} \tag{35}\] \[=-\left(A_{u}+f\left(\alpha_{u}\right)+g\left(\alpha_{u}\right) \right)\beta_{u}+\left(B_{u}f\left(\alpha_{u}\right)-D_{u}g\left(\alpha_{u} \right)\right)-X_{u}\]  
where \(X_{u}=\frac{\partial\alpha_{u}}{\partial\dot{x}_{d}}\ddot{x}_{d}+\frac{ \partial\alpha_{u}}{\partial\dot{y}_{d}}\ddot{y}_{d}+\frac{\partial\alpha_{u} }{\partial\dot{x}_{e}}\dot{x}_{e}+\frac{\partial\alpha_{u}}{\partial\dot{y}_ {e}}\dot{y}_{e}+\frac{\partial\alpha_{u}}{\partial\dot{y}}\dot{\psi}\). According to the nature of the neural shunting model, if \(B_{u}=D_{u}\), we have  
\[\dot{\Phi}_{u}=-\theta_{u}\beta_{u}+B_{u}\alpha_{u}-X_{u} \tag{36}\]  
where \(\theta_{u}=A_{u}+f\left(\alpha_{u}\right)+g\left(\alpha_{u}\right)\). Similarly, if \(B_{r}=D_{r}\), the time derivative of \(\Phi_{r}\) is  
\[\dot{\Phi}_{r}=-\theta_{r}\beta_{r}+B_{r}\chi-X_{r} \tag{37}\]  
where \(\theta_{r}=A_{r}+f\left(\chi\right)+g\left(\chi\right)\), \(X_{r}=\frac{\partial\chi}{\partial\dot{x}_{d}}\ddot{x}_{d}+\frac{\partial\chi }{\partial\dot{y}_{d}}\ddot{y}_{d}+\frac{\partial\chi}{\partial\dot{x}_{e}} \dot{x}_{e}+\frac{\partial\chi}{\partial\dot{y}_{e}}\dot{y}_{e}+\frac{\partial \chi}{\partial\dot{y}}\dot{\psi}\). **Remark 4**. : _[_10_]_\(X_{u}\) and \(X_{r}\) are bounded by \(|X_{u}|\leq\bar{X}_{u}\) and \(|X_{r}|\leq\bar{X}_{r}\), where \(\bar{X}_{u}\) and \(\bar{X}_{r}\) are normal numbers._  
**Lemma 1**. : _[_45_]_ _For any \(\varepsilon>0\) and \(\bar{\zeta}\in R\), the following inequality can be satisfied_  
\[0\leq|\bar{\xi}|-\bar{\zeta}\tanh\left(\bar{\zeta}/\varepsilon\right)\leq\kappa _{3}\varepsilon \tag{38}\]  
_where \(\kappa_{3}\) is a constant that satisfies \(\kappa_{3}=e^{-\left(\kappa_{3}+1\right)}\)._  
**Theorem 1**.
## 2 Molecular Mechanisms of Antimicrobial Agents Recalcitrance in Clinically Important Biofilms
### Biofilm Matrix
#### 2.1.1 Exopolysaccharides  
The Main Polysaccharides Produced by Some Strains of _Pseudomonas aeruginosa_ Biofilms are Psl and Pel.  
Three pentasaccharides, namely D-glucose, D-mannose, and L-rhammose are the structural repeating units of the Psl exopolysaccharidescharide [13; 16]. Controversial data regarding the role played by Psl in resistance to tobramycin have been reported [15; 17; 18]. It was suggested that Psl could physically confine antibiotics. The precise mechanism is still unclear, a charge-based entrapment of cationic antibiotics such as colistin and tobramycin being ruled out since Psl is uncharged.  
Pel exopolysaccharidescharide is another important structural component of the biofilm matrix of _P. aeruginosa_. Identical to Psl, it seems to provide protection against aminoglycosatile antibiotics such as tobramycin and gentamicin, since biofilms lacking Pel showed increased susceptibility to these antibiotics [19]. Again, the recent finding that Pel is positively charged being composed of partially acetylated 1\(\rightarrow\)4 glycosidic linkages of N-acetylgalactosamine and N-acetylglucosamine [20] ruled out the possibility of electrostatic sequestration of cationic antibiotics. It rather appears that instead of complexing the antibiotics, Pel is involved in the cross-linking of e-DNA in the biofilm stalk via ionic attractions, thereby reinforcing the structural integrity of the biofilm matrix. Since e-DNA itself plays a major role in resistance to antibiotics (as discussed below in Section 2.1.2), the mechanisms of acquired resistance mediated by e-DNA and Pel might be interconnected.
## 4 Discussion
### Limitations  
This study was an in vitro investigation of clear aligner biomechanics. Thus, forces and moments measured by the experimental apparatus cannot completely predict the behavior of clear aligners in vivo. There are several limitations to the experimental setup. Firstly, the periodontal ligament was not simulated. The elastic fixture of teeth to the bone imparts a viscoelastic property to the periodontal ligament, allowing for time-dependent elastic compression [25]. The forces and moments measured in this study were greater than what is recommended in the literature and may be partly explained by the lack of the periodontal ligament in the experimental apparatus. Secondly, the effect of masticatory forces was not simulated. The occlusal forces generated during swallowing may exert clinically significant intrusive forces [26]. Thirdly, the presence of saliva was not reproduced. Saliva alters the mechanical properties of clear aligners by water absorption, and hygroscopic expansion of thermoplastic materials has been previously reported [27].
# Effectiveness of Electrode Design Methodologies for Fast EDM Slotting of Thick Silicon Wafers
###### Abstract  
Silicon is the most commonly used material in the electronic industries due to its unique properties, which also make it very difficult to machine using conventional machining. Electrical discharge machining (EDM) is a non-traditional process that is gaining popularity for machining silicon, although a slower machining rate is one of its limitations. This study investigates two electrode design strategies to enhance the efficiency of EDM by improving the material removal rates, reducing tool wear, and refining the quality of machined features. The first approach involves using graphite electrodes in various array configurations (1 \(\times\) 4 to 6 \(\times\) 4) and leg heights (0.2\({}^{\prime\prime}\) and 0.3\({}^{\prime\prime}\)). The second approach employs hollow electrodes with differing wall thicknesses (0.04\({}^{\prime\prime}\), 0.08\({}^{\prime\prime}\), and 0.12\({}^{\prime\prime}\)). The effects of these variables on performance were evaluated by maintaining constant EDM parameters. The results indicate that increasing the number of electrode legs improves the flushing conditions, resulting in shorter machining times. Meanwhile, the shorter electrode height outperforms the taller electrode, providing a higher machining speed. The thinnest wall thickness for hollow electrodes yielded the best performance due to the increased energy distribution. Both electrode design methodologies can be used for the mass fabrication of features with targeted profiles on silicon using the die-sinking EDM process.  
fast EDM slotting; silicon; die-sinking EDM; electrode design; material removal rate (MRR); EDM productivity +
Footnote †: journal: Applied Sciences  
1
# A Brazilian Space Launch System for the Small Satellite Market
## 1 Introduction
In this case, the main differences between the upper stages are related to the total engine thrust and propellant mass. The launch system would operate from the Alcantara Launch Center in Brazil. The launch site is located 2\({}^{\circ}\)20\({}^{\prime}\) S, making it the closest to the Equator, as compared to any other permanent launch centre worldwide. By virtue of its geographic position, launch operations allow rocket expendable stages and payload fairing to fall in the Atlantic Ocean reducing, accordingly, insurance coverage regarding third party and government property damage.
# Preliminary Seismic Hazard Analyses for the Ugandan Region
## 5 Discussion  
For comparison Figure 8 shows a more detailed version of Figure 7a for PGA contours at 10% probability of exceedance in 5 years. The previous seismic hazard study for Uganda  
Figure 7: Progression and distribution of mean PGA values in Uganda computed for 10% probability of exceedance in (**a**) 5 years, (**b**) 10 years, (**c**) 20 years, (**d**) 50 years, (**e**) 100 years, and (**f**) 500 years.  
also calculated PGA values for a return period of 50 years [4]. Results showed that, excluding areas in or close to the rift system would experience a PGA between 0.5 and 0.6 m/s\({}^{2}\), or 0.05 g and 0.06 g, respectively. Figure 8 shows that in similarly comparable areas, a PGA between 0.02 and 0.10 g would be expected. Although the range is wider in this study, it appears within an order of magnitude from the previous study [4]. Additionally, for areas close or within the Ugandan segments of the western branch of the rift valley, calculated PGA values of 0.04 to 0.2 g for earthquakes with a return period of 50 years [4]. Figure 8 shows that in similarly comparable areas, a PGA between 0.10 and 0.27 g would be expected. This study appears to estimate higher levels of shaking in these areas. Overall, these results are similar previous studies where areas in or near the western branch of the rift valley demonstrate higher levels of PGA as well as the area southeast of Lake Alberting [4,6].  
Although the results herein appear to encompass the results from previous studies [4,6], it also shows there are many areas of improvement. By applying relevant GMPEs, this study was able to consider the benefits of multiple correlations appropriate for rock sites. An improvement would be to consider more relevant GMPEs in the logic tree to give a distribution of the hazard results. Moreover, a GMPE for the Ugandan region would be the most beneficial, although admittedly there is not enough real data to develop one. In addition to improvements in the applicability of GMPEs, a better understanding of the seismic zones could have improved this study. The numerous seismic sources of the western branch of the East African Rift Valley were treated as one seismic zone; however, Figure 3 shows significant seismicity in the Lake Victoria area. It is not known if there is an underlying fault system underlying Lake Victoria or if these are actually earthquakes caused by volcanic activity, in which case the earthquake catalog and thus seismic source characterization would be significantly different.
# Comprehensive Review of RF MEMS Switches in Satellite Communications
## 2 Advanced Technologies and Mechanisms in RF MEMS Switches
### Actuation Mechanism
#### 2.1.4 Electrocthermally Actuated RF MEMS Switches  
Figure 1d shows the structure of a typical electrothermally driven RF MEMS switch. Compared to other actuation methods, the primary advantage of electrothermal actuation lies in its lower actuation voltage threshold to initiate switch operations [28].  
The operation of electrothermal RF MEMS switches is based on the thermal expansion coefficient of materials. The heat generated by the current flowing through the resistor on top of the beam causes the beam to deflect. This electrothermal actuation method not only produces a stronger force than electrostatic actuation but also achieves high isolation, requiring only a lower actuation voltage (typically a few volts) [41; 42]. Additionally, [PERSON] et al. [43] conducted a multiphysics analysis of electrothermally driven RF MEMS switches in power limiter applications. The results indicated that compared to their electrostatic counterparts, electrothermal RF MEMS switches offer higher device sensitivity in such applications. However, a major drawback of electrothermal actuation is the relatively larger device structure, leading to increased power consumption during operation. Since electrothermal RF MEMS switches require the application of an actuation current both during the switching and holding phases, they typically consume more electrical energy.
# Image Deblurring Based on an Improved CNN-Transformer Combination Network
## 3 Proposed Approach
### Supervised Attention Block  
In the coarse-to-fine restoration strategy, we must predict the image at different scales. To improve the effectiveness of feature propagation, we designed a supervised-attention block by using the restoration image to refine the feature before being transferred to the next stage. As illustrated in Figure 6, the input feature is passed into two \(3\times 3\) convolutional layers in two different paths. One path is integrated with the degraded blur image \(l_{k}\) and generates the restored image \(\hat{\mathcal{S}}_{\text{k}}\). Then, the restored image passes through a \(3\times 3\) convolutional layer and follows a channel attention block. Next, the attention masks are applied to refine the feature of another path. We used the ground-truth image to supervise and optimize the restored result, and the restored image can be utilized to filter or empha  
Figure 5: The structure of Channel Attention Fusion Block.  
size the features at the current stage in turns. Finally, we added a residual connection with the refined feature before transmitting the feature to the next stage.
## 3 Preliminary
### System Architecture  
Given the adversary model, the basic idea, and the privacy protection model, the problem is how to select a system architecture to select dummy locations and query content. Considering the drawbacks of the TTP and the TTP-free method, in this paper, we adopt a dummy technique that uses historical locations to generate dummy locations to protect the user's privacy, including the organization information and query content. As shown in Figure 5, the system architecture of the dummy technique is a typical independent architecture that avoids the disadvantages of centralized and distributed architectures.  
In the LBS system, there are three participants: The user, the mobile terminal, and the LBS server. Additionally, the privacy protection module of the mobile terminal is the core module of the entire system and consists of an \(\mathit{Area}\) generation module, a dummy location generation module, and a dummy content generation module. The LBS server stores the historical location dataset \(G\), provides the historical location sub-dataset \(G_{sub}\) for the user to generate dummy locations, and calculates query results \(\mathit{Res}\) for the user. The whole process is described as follows:  
* System initialization: This mainly refers to obtaining the user's current location \(L_{0}\) and initializing the historical location dataset \(G\) on the server.
* Initiating a service request: In this stage, the user needs to input initial \(<k,s,l>\) parameters as the input of the privacy protection module.
* \(\mathit{Area}\) generation: \(\mathit{Area}\) is a range of latitude and longitude sent to the LBS server by the user to indicate the latitude and longitude range of the historical location dataset that the user downloads from the LBS server. \(\mathit{Area}\) is determined by the user's current location \(L_{0}\) and \(L_{(k,s)}\). After the user inputs \(<k,s,l>\), the \(\mathit{Area}\) generation module gives \(\mathit{Area}\) according to \(L_{0}\) and \(s\), and sends \(\mathit{Area}\) to the LBS server for downloading \(G_{sub}\).  
Figure 5: System architecture.  
* Historical location data acquisition: The LBS server sends \(G_{sub}\) which meets the requirements of _Area_ to the user.
* Query request construction: After generating dummy locations and dummy query content, the privacy protection module constructs the query request message _Req_ in the light of a specific format.
* Service response: According to the dummy locations and dummy query content in _Req_, the server calculates query results and constructs and feeds back response message _Res_ to the user.
# Hybrid Renewable Energy Systems--A Review of Optimization Approaches and Future Challenges
## 3 HRES Design
### Energy Storage Solution  
The energy produced from renewables with fluctuating generation needs energy storage solutions to compensate for the imbalance between energy generation and demand and ensure a more resilient and cost-effective system. Figure 3 illustrates the number of articles published each year from 2017 to 2024 that focus on different energy storage solutions (ESS), including various energy storage technologies.  
Furthermore, the most innovative ESS contains pumped hydro, battery and hydrogen technologies (see Table 1). Additionally, given data highlights a clear shift in focus over time, with battery and hydrogen storage technologies becoming increasingly prominent in academic research while pumped hydro remains relatively underrepresented. The rapid rise in articles on hydrogen storage, especially in recent years, reflects growing interest in its potential for long-term energy storage and decarbonization efforts. Moreover, nearly half of the articles do not incorporate energy-saving solutions. HRESs with storage components have been implemented worldwide to address energy needs in diverse contexts. For instance, a solar-wind-biomass HRES was deployed in Northeast China, integrating advanced energy storage solutions to address frequent power shortages in rural areas [20]. Similarly, in Algeria, off-grid HRESs combining PV, wind, diesel generators, and battery storage have been installed to provide electricity to residential buildings in remote rural regions [21]. Another notable example is the hydrogen-based HRES in Jeju Island, South Korea, which integrates wind turbines, PV panels, and biomass gasifiers to supply hydrogen for transportation and industrial uses [22].  
Figure 2: Distribution of renewable energy sources in cited references, each number represents the amount of the identified renewable energy sources in HRES in a given year(developed by the authors).  
Almost half of the articles addressing ESS usually integrate hybrid storage solutions, including battery and hydrogen components. This solution gains among researchers every year, demonstrating a growing recognition of the importance of hybrid energy storage systems to meet diverse energy needs and enhance system flexibility and resilience.
# Metalens Antenna Based on an Ultrathin Dual-Polarized Double-Layer Huygens' Metasurface
## 5 Conclusions  
In this work, an ultrathin dual-polarized meta-atom is proposed based on the Huygens' principle, which has the ability to achieve Huygens' resonance, enabling 360\({}^{\circ}\) phase coverage and high transmission. Utilizing this meta-atom, a dual-polarized metalens antenna and a two-channel focusing metalens are designed. The dual-polarized metalens antenna exhibits identical responses to different polarized incident waves and achieves directional radiation. At 25 GHz, it attains a maximum gain of 30.4 dBi, an aperture efficiency of 47%, and a relative bandwidth of 8.4%. In addition to achieving excellent radiation performance, the design features a thin profile and compact structure with the thickness of only one-fifteenth of the incident wavelength. The two-channel focusing metalens realizes different focusing for different polarized incidences, with a focusing efficiency 52.4% for \(x\)-polarization and 48.6% for \(y\)-polarization. The proposed meta-atom enables the realization of desired functionalities while simplifying fabrication and reducing costs. We believe that the proposed meta-atom and the designed metalens would be highly promising for widespread applications in microwave devices, including communication, wireless power transfer, and imaging.  
Figure 9: Normalized electric field distributions of two-channel focusing metalens at 25 GHz under the \(y\)-polarized exciting. (**a**) **E**, (**b**) \(E_{x}\), (**c**) \(E_{y}\), in XOZ plane. (**d**) \(E_{x}\) on the focal plane \(z=100\) mm. (**e**) \(E_{y}\) on the focal plane \(z=75\) mm. The white solid line indicates the position of the metalens.  
**Author Contributions:** Conceptualization, Y.W., S.T. and G.C.; methodology, Y.W., S.T. and G.C.; software, Y.W., S.T., X.H. and G.C.; validation, Y.W., S.T., X.H. and G.C.; formal analysis, Y.W., S.T. and G.C.; investigation, Y.W., S.T., X.H. and G.C.; resources, Y.W., S.T. and G.C.; data curation, Y.W., S.T. and G.C.; writing--original draft preparation, Y.W., S.T. and G.C.; writing--review and editing, Y.W. and S.T.; visualization, Y.W. and S.T.; supervision, Y.W., S.T., X.H. and G.C.; project administration, Y.W., S.T. and G.C.; funding acquisition, G.C. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was supported by the National Natural Science Foundation of China under Grant 92163134 and 62271429.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** The authors declare no conflicts of interest.