esa-sceva/satcom-chunk-collection huggingface dataset:
# Revamping Fluid Catalytic Cracking Unit, and Optimizing Catalyst to Process Heavier Feeds
## 3 Results
### Performance of the FCC Unit before and after the Revamp  
The H-Oil gas oils are heavier, with higher aromatic and nitrogen contents, which makes them more difficult to crack, and produce more coke during fluid catalytic cracking than the straight-run hydrotreated vacuum gas oils [38; 39]. Table 3 exemplifies the difference in the reactivities of the straight-run VGO and the H-Oil gas oils: HAGO, LVGO, and HVGO obtained on the base of laboratory ACE (advanced cracking equipment) unit operating at 527 \({}^{\circ}\)C, with 30 s time on stream, and a catalyst-to-oil ratio = 7.5 wt. Their quality is a function of the H-Oil reaction temperature, H-Oil throughput, the content of FCC slurry oil (SLO) in the H-Oil feed, and the content of the recycling in the H-Oil feed [40]. The H-Oil LVGO is the most difficult to crack, probably because it has \begin{table}
\begin{tabular}{c c c} \hline \hline
**Gas Oils** & **Conversion, wt.\%** & **Coke Yield, wt.\%** \\ \hline SRHTVGO & 77.8 & 3.7 \\ H-Oil HAGO & 58.7 & 5.0 \\ H-Oil LVGO & 53.4 & 5.8 \\ H-Oil HVGO & 58.5 & 8.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Conversion of SRHTVGO, H-Oil HAGO, LVGO, and HVGO obtained in a laboratory ACE unit during the use of catalyst G. The quality of the cracked gas oils was identical to that shown in Table 1.  
the highest nitrogen content, aromatic carbon content, and lowest Kw-characterization factor (see Table 1) [28; 33; 41]. The H-Oil HVGO is the most coke-producing gas oil, probably because it contains the highest level of heavy higher-molecular-weight poly-nuclear aromatic hydrocarbons [28; 33; 41]. The average content of HAGO, LVGO, and HVGO in H-Oil VGO for the 178 studied cases was 19%, 27%, and 54%, respectively, with a variation in HAGO between 5 and 33%; LVGO between 15 and 43%; and HVGO between 36 and 74%. The content of H-Oil VGO in the FCC feed varied between 17 and 37% [39]. As a result of processing, the higher coke made the H-Oil VGO catalyst losses vary between 2.4 and 8.1 t/d before the revamp in 2021, as shown in Figure 3. After the revamp, they fell to 0.9 t/d (Figure 3). The average particle size (APS) of the equilibrium catalyst (E-Cat) increased from 90 to 114 \(\upmu\)m from the maintenance turnaround in 2018 until the next turnaround in 2021, which coincided with the FCCU revamp (Figure 4). After the revamp, the APS of E-Cat decreased to the normal level of 90 \(\upmu\)m (Figure 4). Having in mind that the catalyst losses affect the content of the working fraction of the catalyst (0-80 \(\upmu\)m) and, hence, the catalyst age distribution and activity [35], we decided to compare the LNB FCCU performance at normal catalyst losses before and after the revamp. In this way, the effect of modifications made in the reactor and regenerator section on the FCC unit performance could be evaluated. Table 4 presents data of the operation of the LNB FCCU before and after the revamp.
# Low-Light Photodetectors for Fluorescence Microscopy
## 3 Single Point Detectors
### Hybrid Photodetector (HPD)
#### 3.4.1 Features of HPD  
HPDs have significant advantages over PMTs and other low-light photodetectors in the detection of fluorescence, as discussed below. However, a few disadvantages of HPDs also exist. The extremely high cathode supply voltage (\(-8\) kV) is difficult to deal with, which can be problematic when incorporated into systems.  
Figure 5: Schematic of a single photon avalanche diode (SPAD).  
Figure 6: Schematic of a hybrid photodetector (HPD).  
Low Afterpulse  
HPDs have a notable feature of lower afterpulse due to their uncomplicated internal structure. Therefore, the major cause of afterpulses, i.e., ion feedback, is highly unlikely to occur in HPDs. Afterpulses evaluated for an HPD and a PMT are shown in Figure 7. This graph shows the probability at which afterpulses may be generated by a single photoelectron input. In contrast to the PMT's multiple afterpulses in a time range from 100 ns to 1 \(\upmu\)s, this HPD exhibited only a small number of afterpulses in the time range.  
Comparable low afterpulses have been reportedly achieved solely for superconducting nanowire single photon detectors (SSPDs). These SSPDs have micrometer order active areas and must be operated at a liquid helium temperature [25], as discussed in Section 4.2.
## 5 Concluding Remarks  
This study investigated the ultimate compressive strength of cracked plates and stiffened panels under uniaxial and biaxial loading conditions using nonlinear finite element analysis. The effects of crack size, orientation, and location were systematically examined across various structural configurations. The key findings are as follows:  
* Crack orientation had a significant influence on strength degradation. A 50% transverse crack reduced strength by 22.67%, compared to 9.45% for a longitudinal crack under the same loading,
* Stiffened panels exhibited strong resistance to cracking, with minimal loss even under severe damage scenarios. For example, a 50% longitudinal crack caused only a 2.39% reduction, while the corresponding plate suffered a 24.44% loss,
* Combined (bidirectional) cracks resulted in the most severe reduction in load-carrying capacity among all configurations,
* Structural reinforcement via stiffeners effectively redistributed stress and preserved global integrity, as clearly demonstrated by the superior performance of stiffened panels. These findings provide practical insights that can be applied in the shipbuilding and maintenance industry to estimate residual strength in cracked structures and to plan appropriate repair strategies based on crack size and orientation. Future work will extend this framework to include crack propagation and cumulative damage under realistic loading conditions. Conceptualization, S.J.K. ; methodology, S.J.K. and D.K.K. ; FE analysis, S.J.K. and J.M.S. ; investigation, D.K.K. ; writing--original draft and review and editing, S.J.K. ; writing--review and editing, J.M.S. and D.K.K. ; visualization, S.J.K. ; supervision, D.K.K. ; funding acquisition, J.M.S. All authors have read and agreed to the published version of the manuscript. This research was supported by a National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT, South Korea (NRF-2023R1A2C2002856). It was also conducted as part of the project titled \"Fostering Talent in Advanced Ship Blue Tech\" (RS-2025-02221147), funded by the Ministry of Oceans and Fisheries, Republic of Korea. Not applicable. The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Figure A8: Plate with transverse crack under 1:1 of biaxial compression. Figure A9: Plate with transverse crack under 1:3 of biaxial compression. Figure 14: Plate with combined crack under 1:3 of biaxial compression. Figure 13: Plate with combined crack under 1:1 of biaxial compression. Figure 10: Plate with transverse crack under transverse compression. Figure 10: Stiffened panel with combined crack under transverse compression.
# Quasi-Wireless Capacitive Power Transfer for Wire-Free Robotic Joints +
## 2 Materials and Methods
### Unilateral Wiring Current Path  
The current in the system follows a path that is along the chassis of the robot, over the motor housing/gearbox, and into the QWR. This current path will be defined as a unilateral wiring scheme, since there is no return wire anywhere in the system. Any thermal effects along the motor and associated gear box is an area of concern when being incorporated into the unilateral circuit. To investigate this, the skin depth was calculated to determine the penetration of the unilateral current flow. Using the standard equation for skin depth,  
\[\delta=\sqrt{\frac{\rho}{\pi f\mu}}, \tag{24}\]  
where \(\rho\) is the resistivity of the material the current flows over, \(f\) is the operating frequency, and \(\mu\) is the permeability of material. Assuming the motor housing is a basic steel, \(\mu\) can be estimated at approximately \(1200\mu_{0}\) with a resistivity of \(1\times 10^{-7}\)\(\Omega\)m. The skin depth is on the order of 3 \(\upmu\)m. This number is sufficient to warrant an experimental test with these motors to determine if any thermal heating occurs.  
Figure 8 is a photograph of an experiment to test the heating through the motor. In this test, the motor was connected in series with an RF amplifier (The A150 RF Amplifier from Electronics and Innovation, LTD) and a QWR. This experiment was run for an hour, with 15 W being delivered to the QWR through the motor. The input current was measured at 474 mA\({}_{RMS}\). The temperature of the coil was found to be 37.72 \({}^{\circ}\)C and the motor was 26.29 \({}^{\circ}\)C. This was compared to a room temperature of 23 \({}^{\circ}\)C. With only a 3 degree temperature rise over the course of the 1 h, the amount of thermal heating was insignificant. Therefore, it is possible to transfer power over the motor housing and subsequent gearbox with little thermal effects due to the QWR's high-impedance operation. There are obvious limits to this approach as the system is scaled; it will become important to form capacitive links between the motor and adjacent joint. This is a focus for future work. However, the unilateral nature makes such capacitive linkages significantly easier than a bilateral CPT system. A bilateral CPT approach would require 2 transmitting plates and 2 receiving plates per linkage, increasing design complexity. The unilateral system needs only 1 transmitting plate and 1 receiving plate per linkage.  
Figure 7: The schematic for the DC H-bridge rectifier with the physical AC–DC circuit board in the corner.
## 2 Acquisition and Characterization of Pore Structure
### Nitrogen Adsorption  
The nitrogen adsorption method is a pore structure characterization technique for porous media based on the [PERSON] monolayer adsorption theory [31]. Scholars such as [PERSON], [PERSON], and [PERSON] extended the monolayer adsorption theory to develop the multilayer adsorption theory, also known as the BET theory [32]. This theory has become the most commonly used theoretical foundation in gas adsorption characterization methods for porous media. It has been widely applied in the study and testing of particle surface adsorption properties, such as specific surface area, pore volume, and pore size distribution.  
The nitrogen adsorption method is primarily used to obtain data on specific surface area, pore volume, and pore size distribution, particularly for characterizing micropores. This method provides detailed information about the pore structure; however, it requires strict sample preparation and relatively long experimental times, as it may take a longer period to reach adsorption equilibrium, leading to poorer reproducibility of the experiments. Additionally, nitrogen adsorption at low temperatures can be influenced by the chemical properties of the sample surface, necessitating thorough preliminary analysis. Moreover, compared to nitrogen, hydrogen molecules are smaller, allowing hydrogen to enter smaller micropores. Therefore, during pore characterization, hydrogen adsorption can provide more detailed information about micropore and ultra-micropore distribution than nitrogen, making it especially suitable for studying small pores.
# Ad Hoc Data Foraging in a Life Sciences Community Ecosystem Using SoDa +
## 3 SoDa Architecture
### Resource Recommendation  
Existing resources in SoDa can be browsed from a searchable index, or a specification in the form of a paragraph for the resource needs can be used as a search key in natural English. For example,  
_Need to find normalized sperm RNA-seq expression data for differential expression analysis (using DESeq2, edgeR, or Limma)._  
The Resource ReCommeder system ResCom accepts this request and suggests a ranked list of databases, prioritizing the most relevant at the top. Not only does ResCom suggest the databases, it also generates a possible scheme of a table that can be accessed via a web link, i.e., a URL.  
In response to the above request, as an example, ResCom will first search for a matching data set in SoDa archive. In SoDa, all table schemes are semantically described in some detail using natural language and their possible usage is also included in these descriptions. These descriptions are stored in SoDa's vector database for a possible linguistic analysis using an LLM, such as ChatGPT, to ascertain query relevance.  
In the event a table could not be identified, or the user requests an external search, ResCom uses PubMed abstracts as the first level of descriptors of data to find a match. If a sufficient match is found, the list of abstracts are organized, ranked in order of relevence, and vectorized for semantic matching. Database links found in the abstracts are explored exhaustively using a link, hoping to identify a database with the closest match and presented to the user for review with two options--accept or search next. The search ultimately ends in a success or failure.  
The process of successfully identifying resources undergoes a secondary step. In this step, a machine-readable and editable description on the nature and capabilities of the resource is generated (see Figure 2 showing this process for the resource description generation for the DisGeNET ([[https://www.disgenet.org/](https://www.disgenet.org/)]([https://www.disgenet.org/](https://www.disgenet.org/)) (accessed on 1 December 2024) database). The resource description can be used in multiple different ways. The major use of the descriptions, however, is by the workflow generation system Needle ([PERSON], 2018), as discussed in Section 3.5. Needle uses resource descriptions to identify schema heterogeneity and schema matchers for their resolution, suitable wrappers for data access, and the trustworthiness of the resource. A crowd computing approach is adopted to ensure the accuracy and usefulness of the generated resource description within a community knowledge sharing ecosystem.
# Theis: A Booster for Building Safer Systems Using the Rust Programming Language
## 4 Design and Construction of Thetis
### Functionally Equivalent Replacement  
#### 4.1.1 Replacement of Mutable Static Variables  
Static variables are placed in a data segment at initialization, and the data in that space occupy that storage for the entire runtime of the program. When multiple threads access the same mutable static variable, concurrency issues may occur, including Read-After-Write (RAW), Write-After-Read (WAR), and Write-After-Write (WAW) issues. The most common problem is data competition, which may cause deadlocks and result in invalid data.  
Thetis detects mutable static variable usage based on features and replaces them with mutexes. It can directly transform the unsafe fragments into safe code, as shown in Figure 3. Mutex<T>, a smart pointer in Rust, is designed under the principle of _interior mutability_. _Interior mutability_[44] means that the value bound to a variable can be modified, even if the variable itself is immutable or immutably borrowed. This provides a great functional alternative for accessing or modifying mutable static variables. Meanwhile, the compiler can perform borrow checking for a mutex. When operations violate borrow-checking rules, the code may compile successfully but will suffer from panic at runtime. By replacing mutable static variables with mutexes, Thetis can completely eliminate this type of unsafe fragment, significantly reducing computational overhead. We use LMbench to measure the performance overhead in Section 5.2.  
Mutex replacement can cause deadlock issues. System-level deadlocks occur when multiple processes or threads in a computer system are unable to proceed because each is waiting for a resource that is held by another process. The most common cause of deadlocks is forgetting to use unlock mechanisms later [45]. In the C/C++ language, mutexes must be manually unlocked; otherwise, it will cause deadlocks and reduce system concurrency and performance. Thanks to the lifetime feature of Rust, it will automatically release the lock after the lifetime ends. This greatly reduces the possibility of deadlocks after replacement. In the remaining deadlock situations, we consider that the use of mutable static variables poses a thread safety issue rather than being caused by a mutex. This requires modifications to the code logic. We use an example to verify the correctness of module functionality after replacement. In Listing 5, we provide the code before and after the replacement. Actual operation results show that replacing the module works correctly. Replacement in more complex scenarios is conducted through experiments.  
Figure 3: Replacement of mutable static variables.  
```
//Beforereplacement//AfterreplacementstaticmutTE:u32=0;staticTE:Mutex<u32>=Mutex::new(0);fnadt(inc:u32){fnadt(inc:u32){unsafe{TE+=inc;}lett=TE.lock().unwarp();} *t+=inc; }
```  
In general, replacing mutable static variables with mutexes improves code maintainability and clearly expresses the intent and constraints of the code, thereby reducing the possibility of errors.
## 4 Signal Processing  
Major steps of the proposed signal processing approach are shown in Figure 3, which illustrates the process of human respiration extraction in the outdoor injured people scenario using UWB radar. The signal processing approach is divided into five blocks, including range migration compensation, observed signals extraction, pre-processing, ICA and respiratory signal extraction.
# Centimeter-Level Precise Orbit Determination for the Luojia-1A Satellite Using BeiDou Observations
## 5 Luojia-1A Satellite POD Results and Discussion  
### The Procedure of Luojia-1A Satellite POD  
Several steps are required for the procedure of Luojia-1A satellite reduced dynamic orbit determination, which can be briefly described as follows. Firstly, obtaining the prior orbit of the satellite using the BDS pseudorange observations. The precise orbit and clocks products of BeiDou satellites, as well as the ERP products, are adopted to process the pseudorange positioning orbit result and then fitting the prior orbit using numerical integration. Secondly, data preprocessing for the zero difference phase observations, including cycle slip detection and outlier detection. After that, estimate the orbital parameters, dynamic parameters, and the pseudo-stochastic parameters for solving the improved satellite orbit, which is determined based on the prior orbit and the screened phase observations. The data preprocessing as well as the orbit improving procedure are iterated for the precise solution. Finally, the orbit generated from the last step is introduced as the prior orbit, and the screened phase observations are used to estimate the parameters; thus, the precise orbit result is obtained.  
With regards to the orbit precision evaluation method, the overlapping comparison method is used since the Luojia-1A satellite does not equip with the laser reflector array (LRA), and there is no precise reference orbit for comparison. The overlapping comparison strategy for the Luojia-1A satellite is illustrated in Figure 7. The observations of the Luojia-1A satellite in 2018 DOY159 are divided into two observational arcs, one contains the begin epoch until 9:00:30, the other contains 2:14:52 until the last epoch, and then two observational arcs are determined respectively. Therefore, the difference of two solutions in the overlapped part is used to assess the Luojia-1A orbit precision in this study.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Type of Parameter** & **Settings** \\ \hline Observations & BDS B1 and B2 code and carrier-phase observations \\ Sample rate & 5 s \\ Cut off angle & 0° \\ BeiDou antenna phase center & PCV.atx [27] \\ Relativistic effects & IERS 2010 \\ Ionospheric error & Ionosphere-free linear combination \\ Earth rotation & ERP products Provided by Wuhan University \\ Nutation & IAU2000R06 \\ Polar motion & IERS2010 XY \\ BeiDou precise orbit and clock products & WUM products Provided by Wuhan University \\ Earth’s gravity field & EGM2008 model with the degree of 120 \\ Solid Earth tides & IERS 2010 \\ Ocean tides & FES 2004 \\ Planetary calendar & DE405 \\ Solar pressure & ECOM \\ Pseudo-stochastic parameters & Radial, along-track, and cross-track directions \\ \hline \hline \end{tabular}
\end{table}
Table 1: The data processing strategies for Luojia-1A satellite POD.
# A Privacy-Preserving Record Linkage Method Based on Secret Sharing and Blockchain
## 3 Preliminaries and Background
### InterPlanetary File System  
To avoid the high storage costs of blockchain, this method employs IPFS as a distributed file system to store large-scale data, such as Bloom filter shares, masks, and intermediate results. The blockchain only records the unique CIDs of these data. Computational nodes or participants, upon authorization via smart contracts, retrieve the required data directly from IPFS using the CIDs [21]. This strategy of combining on-chain metadata with off-chain data leverages IPFS's content addressing and distributed storage capabilities, significantly enhancing the system's scalability [22].