esa-sceva/satcom-chunk-collection huggingface dataset:
# Enhancing the Photocatalytic Activity of Immobilized TiO2 Using Laser-Micropatterned Surfaces
## 2 Materials and Methods  
### Standards and Reagents  
Analytical standards of atrazine (purity 99.1%), bisphenol-a, and 2,4,6-trichlorophenol were purchased by Sigma-Aldrich (Seelze, Germany) and isotopic labeled atrazine-d\({}_{5}\) standard solution was obtained from Dr. Ehrenstorfer GmbH (Augsburg, Germany).  
Acetonitrile (ACN) of LC-MS grade (\(\geq\)99.9%) was supplied by Fisher Chemical. Ultra-pure water (18.2 M\(\Omega\) cm at 25 \({}^{\circ}\)C) was produced in the lab using a Temak TSDW10 water purification system (TEMAK, Athens, Greece).  
For the synthesis of TiO\({}_{2}\) films, the following high-purity starting materials were used: titanium (IV) isopropoxide (TTIP; 98%, Acros Organics, Waltham, MA, USA), 2-methoxyethanol (C\({}_{3}\)H\({}_{8}\)O\({}_{2}\); 99.8%, Acros Organics, Waltham, MA, USA), nitric acid (HNO\({}_{3}\); 70%, Sigma-Aldrich), and commercial Degussa P25 (Degussa AG, Frankfurt, Germany).
## 4 Conclusions  
In the present study, numerical analysis was performed for different AHT methods, namely passive, compound, and active. Circular perforated inserts were used in passive AHT, a rotating inner pipe was used in active AHT, and rotating circular perforated inserts were utilized in compound AHT. The proposed applications in each method provided a significant heat transfer rate improvement. Consequently, the main findings were as follows:  
* Passive AHT: At \(N=7\), the heat transfer rate of the static circular perforated pipe increased by 41.8%. However, the thermal performance factor of 0.72 was relatively low due to the abrupt increase in pressure drop, which is not well-balanced with the convective heat transfer improvement.
* Active AHT: Rotating the inner pipe up to 300 rad/s enhanced the heat transfer rate by 4.28 times. The thermal performance factor at this speed is 2.02, which was indicative of the AHT efficiency. Moreover, the pressure drop recorded was comparatively lower than the active and compound AHT methods performed.
* Compound AHT: The rotation of inserts intensified swirls and vortices, resulting in rapid thermal mixing and a 47.5% improvement in heat transfer rate at 300 rad/s. The thermal performance factor is recorded at 0.80, indicating a better CCTHE effectiveness than the passive AHT.  
Figure 27: \(\alpha\) and Nu at varied rotational speeds (\(\omega\)) during Compound AHT.  
In conclusion, all AHT techniques applied were capable in terms of enhancing the heat transfer rate of the CCTHE, with the active AHT (rotating inner pipe) resulting in the most efficient heat transfer.  
This work recommends a further study on methods of lowering the pressure drop across the CCTHE caused by inserts. Additionally, a more comprehensive take on the cost analysis of inner pipe rotation active AHT is advised to prove its practical feasibility.  
Conceptualization, L.G.A.A. and B.D.J.; methodology, L.G.A.A.; software, L.G.A.A.; validation, L.G.A.A. and B.D.J.; formal analysis, L.G.A.A. and B.D.J.; investigation, L.G.A.A.; resources, L.G.A.A. and B.D.J.; data curation, L.G.A.A. and B.D.J.; writing--original draft preparation, L.G.A.A.; writing--review and editing, L.G.A.A. and B.D.J.; visualization, L.G.A.A. and B.D.J.; supervision, B.D.J. All authors have read and agreed to the published version of the manuscript.  
The APC was funded by the Mapua Institute for Creative and Research Opportunities (MICRO), Mapua University, 658 Muralla St., Intramuros, Manila 1002, Philippines.  
Not applicable.  
The data presented in this study are available on request from the corresponding author, due to considerations regarding ongoing research works.  
The authors would like to thank Mapua University for providing the software. The authors also appreciate the support from the School of Graduate Studies and the School of Chemical, Biological, and Materials Engineering and Sciences, Mapua University.  
The authors declare no conflicts of interest.
## 4 Results and Discussion
### Predictive ML Models Created over a Set of Predictors Optimized by the Pareto 80/20 Rule  
Figure 12 shows a Pareto diagram where the observed input variables are ordered according to the value of PI, from the highest to the lowest, by the ranking shown in Figure 9 [48]. The value of the cumulative curve for any input variable is equal to the sum of the PI values of individual predictors up to the observed variable, moving from the left to the right side of the diagram. According to the Pareto 80/20 rule, the goal is to find the first point on the curve with a cumulative value equal to or greater than 80%. This optimal point is marked in Figure 12, and the cumulative percentage in it is 81.34% for 11 input  
Figure 11: Correlation of ML models prediction results with data test set.  
Figure 10: Relative error of ML models testing.  
variables. According to the results shown in Figure 10, the k-NN model is selected as the best solution in this optimization approach, whose relative error at that point is \(RE\) = 0.049, while the correlation is equal to 0.975 (Figure 11).
## 6 Conclusions  
On the basis of the research obtained from the first and the second stage of the experiment, and the thermal images analysis, general assumptions about the favorable TES parameters of the recycled ceramic concrete were confirmed. Results obtained during the tests have confirmed the beneficial value of the heat stored during the heating, as well as the relatively low temperature drops of concretes while cooling. The tests at higher temperatures were relatively close to those obtained at the lower temperature range. All of the concretes showed good accumulating properties, considerably higher than other compared materials, e.g., red ceramics or fireclay bricks. The tests at higher temperatures, however, have shown that only the heat-resistant concrete (CCA-AC) has appropriate the parameters to work in the operational conditions of a fireplace. Other concretes were characterized by structural damage (mainly cracks) due to the influence of the elevated temperature.  
The additional conclusions obtained from the literature study, research, and analysis can be formulated as follows:  
1. The parameters that determine the possibility of using the material as the TES material are as follows: the heat capacity (the material capacity to absorb and store heat in its volume), and the thermal power (the material ability to return the energy to the environment, in a given time).  
Figure 7: Surface of CCA-AC (**left**) and CGA-AC (**right**) samples after heating at 400 \({}^{\circ}\)C.  
2. The primary factor determining the TES properties is the maximum temperature to which the material can be heated.
3. Concrete made with ceramic waste aggregate and alumina cement, due to the ability to work in temperatures up to 1000 \({}^{\circ}\)C, has a high heat accumulation ability. This value is approximately two times higher than that of red ceramics and fireclay bricks. The results of the research also point to the relatively high thermal power of this material.
4. The concrete prepared from ceramic waste aggregate is a good heat accumulator. These concretes may, thus, be the starting point for the practical application of such materials to the manufacture of condensing furnaces, or to the interior of fireplaces. Its additional advantage is the ease of forming any shape and the possibility of embedding it in the workplace without previous firing, as is in the case of the ceramics used so far.  
This work was financially supported by Polish Ministry of Science and Higher Education within the statutory research of cooperating universities: The Main School of Fire Service in Warsaw, Lublin University of Technology, and Collegium Mazovia in Siedlce.  
[PERSON] and [PERSON] conceived the idea of the experiment, conducted the experimental part, and analyzed the results. [PERSON] translated the article, analyzed the results, and provided manuscript formatting. All authors interpreted and discussed the experimental results. All authors of the article provided substantive comments.  
The authors declare no conflict of interest.
# Streetlight Control System Based on Wireless Communication over DALI Protocol
## 3 System Architecture
### Lighting Control: DALI  
Most current digital ballasts implement the DALI protocol. Additionally, it is also implemented in low-voltage transformers, movement detectors, wall switches, _etc._  
The main reason for choosing DALI over other lighting control protocols is that it allows for bidirectional communication (unlike X-10, 0-10 V and DMX). On the other hand, its physical interface is very simple, as it uses only two wires for the control signals. Thanks to the use of this protocol, the following advantages are achieved:  
* Failure detection for lamps or electric failures
* The ability to take and send data related to the lamp's status
* Level dimming
* Better energy consumption
* Information on the lamp's voltage, current and power factor
* The ability to execute other actions, such as turning the lights on/off, controlling them, _etc._  
The physical layer of the DALI protocol uses Differential Manchester encoding, in which the logic values are represented by transitions in the signal, as shown by Figure 3. Each node is attached to the bus line via its two bus terminals, which provide differential receiving and transmitting capability.  
The DALI protocol is based on the master/slave model, in which one master can control up to 64 slaves. The master sends frames (forward messages) to any slave device of the system and receives a response frame (backward message) if the forward frame requested a response. As shown by Figure 4, a forward master-slave frame (ballast) consists of 19 bits, distributed as follows: one starting bit, eight bits for routing, another eight bits for data and two stop bits. Meanwhile, a backward response frame consists of 11 bits, a start bit, 8 bits for data and two stop bits. At the physical layer, DALI uses an effective data transfer rate of 1.2 kb/s and a tolerance in the timing bit of 10%.  
The main disadvantage of the DALI protocol is that it is not implemented in most microcontrollers. In addition, the logic levels of the physical layer have incompatible voltage values with most microcontroller-based systems.
###### Abstract  
Terrestrial and satellite communications, tactical data links, positioning, navigation, and timing (PNT), as well as distributed sensing will continue to require precise timing and the ability to synchronize and disseminate time effectively. However, the supply of space-qualified clocks that meet Global Navigation Satellite Systems (GNSS)-level performance standards is limited. As the awareness of potential disruptions to GNSS due to adversarial actions grows, the current reliance on GNSS-level timing appears costly and outdated. This is especially relevant given the benefits of developing robust and stable time scale references in orbit, especially as various alternatives to GNSS are being explored. The onboard realization of clock ensembles is particularly promising for applications such as those providing the on-demand dissemination of a reference time scale for navigation services via a proliferated Low-Earth Orbit (pLEO) constellation. This article investigates potential inter-satellite network architectures for coordinating time and frequency across pLEO platforms. These architectures dynamically allocate radio resources for clock data transport based on the requirements for pLEO time scale formations. Additionally, this work proposes a model-based control system for wireless networked timekeeping systems. It envisions the optimal placement of critical information concerning the implicit ensemble mean (IEM) estimation across a multi-platform clock ensemble, which can offer better stability than relying on any single ensemble member. This approach aims to reduce data traffic flexibly. By making the IEM estimation sensor more intelligent and running it on the anchor platform while also optimizing the steering of remote frequency standards on participating platforms, the networked control system can better predict the future behavior of local reference clocks paired with low-noise oscillators. This system would then send precise IEM estimation information at critical moments to ensure a common pLEO time scale is realized across all participating platforms. Clock steering is essential for establishing these time scales, and the effectiveness of the realization depends on the selected control intervals and steering techniques. To enhance performance reliability beyond what the existing Linear Quadratic Gaussian (LQG) control technique can provide, the minimal-cost-variance (MCV) control theory is proposed for clock steering operations. The steering process enabled by the MCV control technique significantly impacts the overall performance reliability of the time scale, which is generated by the onboard ensemble of compact, lightweight, and low-power clocks. This is achieved by minimizing the variance of the chi-squared random performance of LQG control while maintaining a constraint on its mean.  
**Keywords:** proliferated low-Earth-orbit constellation; on-demand navigation over communications; radio resource allocation; clock-to-clock difference measurements; multi-platform clock ensemble; clock-ensemble Kalman filter; implicit ensemble mean; networked control system; clock steering based on minimal-cost-variance control
# The Integration of Internet of Things and Machine Learning for Energy Prediction of Wind Turbines
## 2 IoT and Wind Energy
### SCADA Systems and M2M for IoE-Enabled Wind Farms  
Due to the harsh, expansive, and isolated nature of wind farm sites, SCADA systems must possess the ability to efficiently monitor and control operations. Furthermore, the intricate nature of a wind turbine necessitates the perception of wind farms as a collection of interconnected systems. Hence, it is imperative to enhance the existing SCADA systems employed for monitoring and controlling grids and power plants, including wind turbines, by including advanced multilayered interactive sensing, communication, and control functionalities [17]. Presently, energy providers are requiring the incorporation of wind farms SCADA systems into their asset management software, such as enterprise resource planning (ERP) and customer resource management (CRM). Figure 7 presents a concise overview of the responsibilities and objectives that upcoming SCADA systems for wind energy will encompass.  
Figure 6: CP integration of WECS.  
In the future, wind farms will require the use of CP SCADA systems that are implemented using IoT technology for their operation and management. The notion of the IoT is exemplified by the implementation of a wireless sensor network (WSN) for an industrial process, which allows for remote monitoring via the internet [16,18]. A customizable SCADA system with decentralized intelligence and decision-making capabilities is provided based on a CP model of a power system. The system comprises three primary elements: Intelligent machines, analytics, and operators. This concept is employed in a wind control platform to oversee the synchronization of wind turbines in a farm. The SCADA system is anticipated to leverage current advancements in computing and networking to offer monitoring and control services via the internet, aligning with the fundamental essence of the IoT. Efficiently processing large amounts of raw data requires the use of self-organizing CPS networks. Hence, CP wind farms necessitate the implementation of novel network standards, protocols, and infrastructures. M2M communications is an increasingly important component of the IoT [19]. M2M connections enable the transmission of information between intelligent equipment, business applications, and data servers. Anticipated developments in M2M technology will broaden the scope of connections beyond individualized interactions to a model where producers and consumers are interconnected. A planned infrastructure for M2M communications aims to enable smart wind farms to efficiently communicate measured data and enhance their intelligence among wind turbines. A proposed cloud-based M2M telemetry system aims to efficiently handle and visually represent data for suppliers of renewable energy [20]. Furthermore, content management systems are getting more intelligent using M2M technology.
## 2 Materials and Methods
### Analysis of the OWC System
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Wavelength [\(\mu\)m]**} & \multicolumn{3}{c}{**Attenuation [1/km]**} \\ \cline{2-4}  & **RH = 50\%** & **RH = 70\%** & **RH = 100\%** \\ \hline
1.5 & 0.014 & 0.02 & 0.028 \\
4.5 & 1.23 & 1.31 & 1.42 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Attenuation coefficient by air relative humidity (HITRAN database). have a frequency of a few kHz and can be minimized using a tracking device. Regarding short-term beam spreading, this effect is typically neglected. The wavelength dependency of these turbulences is not strong. Actually, OWC systems are most often affected by scintillation. Random wave front interference causes peaks and dips in the high-dynamic receiver output signal. This effect can be minimized using, for example, aperture averaging, diversity techniques, adaptive optics, or some modulation techniques [35]. It also was shown that an operation at longer wavelengths allows for better transmission during turbulence [36]. However, strong turbulence causes comparable radiation attenuation for NIR, SWIR, and MWIR ranges. The OWC system performances also can be limited by a pointing error specifying the misalignment between a transmitter and a receiver. Thermal expansions, strong wind, and weak earthquakes are the main factors of building sway and mechanical vibration moving the OWC transceivers from the common line of sight [37]. The average received signal is decreased and, consequently, the bit-error-rate (BER) is increased. Analyzing the SNR level, the main source of noise power is the receiver noise. It is generated in a photodetector and its front-end electronics. The photodetector noise is usually described by the Noise Equivalent Power (\(NEP\)):  
\[NEP=\frac{\sqrt{A_{d}\Delta f}}{D^{*}}, \tag{2}\]  
where \(D^{*}\)--is the detectivity, \(A_{d}\) is the active surface of the photodetector, and \(\Delta f\) is the noise bandwidth. The \(NEP\) value determines the fundamental detection limit of the transmitter signal. This limit, however, is increased by front-end noises. The total power noise \(N_{T}\) is equal to:  
\[N_{T}=N_{det}G+N_{f-e}, \tag{3}\]  
where \(N_{det}\) is the photodetector noise signal, \(G\) is the signal gain of the photodetector front-end, and \(N_{f-e}\) is the front-end noise contribution.
## 2 Blockchain-Based Data Storage Methods: On-Chain, Off-Chain, and Hybrid Approaches
### Hybrid Storage Approaches
#### 2.3.3 Layer-2 Optimizations  
Layer-2 solutions reduce transaction loads on the main blockchain, providing a more scalable and faster infrastructure. These solutions involve processing data on a secondary layer while storing only summary information on the main blockchain.  
* _Rollups_: Rollups process transactions on Layer-2 and store summary data on Layer-1. This method offers high scalability, making it particularly effective for networks with high transaction volumes. However, technical complexity and implementation challenges can hinder widespread adoption [19; 20].
* _Plasma_: Plasma is based on processing data on subchains while storing transaction summaries on the main blockchain. This mechanism provides a secure Layer-2 solution, but coordination challenges between subchains introduce operational complexities [52; 95].
* _State Channels_: State Channels allow transactions to be executed off-chain, with only the final results recorded on the blockchain. This method provides low latency and high transaction speed. However, the setup process is complex, requiring additional technical knowledge for users [96; 97].  
Layer-2 solutions play a crucial role in enhancing the scalability of blockchain networks by processing transactions off-chain while ensuring security through various cryptographic mechanisms [52; 97]. Technologies such as ZK-Rollups, Optimistic Rollups, Plasma, andState Channels offer different trade-offs in terms of decentralization, performance, and security [95; 96].  
However, despite their advantages, Layer-2 solutions introduce certain technical and security challenges. One significant concern is data availability attacks, particularly in Optimistic Rollups, where malicious validators may delay fraud proofs [96]. While ZK-Rollups eliminate this risk, they require substantial computational resources, leading to high operational costs and verification delays [95]. Similarly, Plasma chains suffer from exit fraud risks and complex withdrawal mechanisms, which make them less practical for real-time applications [97].  
Additionally, state channels require counterparties to be online for transactions to be settled, which limits their use cases compared to fully decentralized Layer-1 solutions [97]. The table below presents a detailed comparison of different Layer-2 scaling solutions, highlighting their security models, advantages, and limitations. A comparative analysis of Layer-2 scaling solutions is provided in Table 4.  
These challenges suggest that while Layer-2 solutions provide significant scalability improvements, their limitations must be considered when designing blockchain-based storage models [95; 96; 97].