esa-sceva/satcom-chunk-collection huggingface dataset:
# Investigation of In Situ and Ex Situ Passivation of Pyrophoric Uranium-Niobium Alloy Powder
## 3 Results and Discussion  
### Pyrohoricity Results  
The initial syntheses of in situ-passivated U-6 Nb spheres were conducted with passivation gas flow rates of between 0 and 10 SLPM, and the pyrophoricity of the resulting powder was evaluated using the sparkle test. The unpassivated powder (0 SLPM) and the powder passivated in situ with 2 SLPM of passivation gas failed the sparkle test, exhibiting bright sparks and fire. In contrast, powders synthesized with 1, 3, 4, 5, and 10 SLPM of passivation gas passed the test. Due to the observed pyrophoricity in the 1-3 SLPM range, 5 SLPM was selected as the default passivation gas flow rate for subsequent powder  
Figure 1: Comparison of a passed (**a**) and a failed (**b–e**) sparkle test; (**a**) passed sparkle test exhibiting no pyrophoricity; (**b**) failed sparkle test with bright sparks and molten metal; (**c**) smoke and residual embers filling the testing chamber immediately following a failed test; (**d**) persistent reactive fine dust; (**e**) embers smoldering for several minutes post-test.  
syntheses and characterization to ensure a safety margin. Among 22 subsequent batches synthesized with 5 SLPM of passivation gas, 17 passed the sparkle test, while five failed during at least one of the six drops.  
For ex situ passivation, five synthesized batches of unpassivated U-6 Nb spheres were allowed to sit in argon-filled plastic containers to allow for the slow diffusion of oxygen through the polyethylene walls and into the powder. An extended duration of seven months was selected to ensure complete passivation to minimize the risk of incomplete oxidation. After the exposure period, all five batches of ex situ-passivated powders successfully passed the sparkle test, confirming their non-pyrophoric nature.
# Sphingolipidoses and Retinal Involvement: A Comprehensive Review
## 4 Subtypes of Sphingolipidoses
### GM1 Gangliosiosis
#### 4.3.2 Retinal Manifestations  
Ocular involvement can affect various structures of the visual system and has been reported as early as 1959 [103]. Retinal involvement is primarily characterized by the presence of a macular cherry-red spot, which is almost always present in type 1 and type 2, along with retinal hemorrhages [84; 87; 88].  
In a histopathological study conducted by [PERSON] et al. analyzing both eyes from a young patient with GM1 gangliosidosis and a cherry-red macula, the authors observed ganglioside accumulations in the cytoplasm of retinal ganglion cells [99]. These accumulations are presumably responsible for this alteration, which, although not exclusive to this condition, may aid in early diagnosis [104]. Furthermore, a retinal functional study in mice demonstrated that GM1 gangliosidosis is associated with a widespread reduction in VEPs [19].
## 2 Materials and Methods  
### Study Design  
This retrospective cohort study involved the inclusion of 5708 assessments of consecutive outpatient individuals who underwent screening examinations for potential fatty liver disease using transient elastography (TE). The examinations took place at the Nutrition Clinic of the \"Mater Domini\" University Hospital in Catanzaro, Italy, spanning the period from April 2014 to March 2021. For this study, data available in existing databases was used. We included adults of both genders, those \(\geq\)50 years old, with a wide range of body mass index (BMI), whose HGS data were available. We excluded individuals from the study who displayed laboratory and clinical indications of chronic hepatitis B and/or C virus infections. Additionally, we excluded those with a history of or current alcohol misuse, defined as consuming more than 20 g of alcohol per day, where hard liquor equals 45 mL (1.5 oz), wine equals 120 mL (4 oz), and beer equals 350 mL (12 oz), each containing 10 g of alcohol, as confirmed by their medical records. Furthermore, we excluded individuals with ascites and liver cirrhosis, autoimmune liver disease, cholestatic liver disease, chronic kidney disease, nephrotic syndrome, pregnancy, and those taking methotrexate, corticosteroids, antiretroviral agents, valproate, and amiodarone. For the purpose of this analysis, we also removed all patients with a liver stiffness value of \(\geq\)7 kPa [45] and those for whom it was technically infeasible to evaluate the CAP score. To detect a difference in the prevalence of hepatic steatosis of at least 18% between HGS tertiles, with a power of 80% and a two-sided significance level of 0.05, approximately 243 participants are needed. Among the adults initially selected, 388 patients meet all eligibility criteria (Figure 1). The protocol was approved by the \"Mater Domini\" Azienda University Hospital's local ethical committee (protocol n.121 on 21 April 2023). All participants provided written informed consent, and this study adhered to the ethical guidelines specified in the Declaration of Helsinki. All participants underwent a medical interview, during which anthropometric measurements, HGS assessments, and TE evaluations were conducted. The baseline clinical characteristics of the population, as well as their biochemical parameters, were retrieved from their medical records. Various cardiovascular risk factors were defined according to the following criteria: Hypertension: systolic blood pressure (SBP) \(\geq\) 140 mmHg and/or diastolic blood pressure (DBP) \(\geq\) 90 mmHg or the use of antihypertensive medications.  
Dyslipidemia: total cholesterol levels > 200 mg/dL and/or triglycerides > 200 mg/dL or the use of lipid-lowering drugs.  
Type 2 diabetes: fasting blood glucose levels \(\geq\) 126 mg/dL or the use of antidiabetic treatments.  
General obesity: a body mass index (BMI) of \(\geq\)30 kg/m\({}^{2}\).  
Smoking: individuals who were current or past smokers (at least in the preceding four months).
# Impact of Chirp in High-Capacity Optical Metro Networks Employing Directly-Modulated VCSELs
###### Abstract  
Directly modulated long-wavelength vertical cavity surface emitting lasers (VCSELs) are considered for the implementation of sliceable bandwidth/bitrate variable transceivers for very high capacity transmission (higher than 50 Gb/s per wavelength) in metropolitan area systems characterized by reduced cost, power consumption, and footprint. The impact of the frequency chirp measured for InP VCSELs with different kinds of design (high-bandwidth very short cavity and widely-tunable with micro electro-mechanical systems (MEMS) top mirror) is analyzed in case of discrete multitone (DMT) direct modulation in combination with 25-GHz wavelength selective switch (WSS) filtering. The maximum transmitted capacity for both dual side- and single side-band DMT modulation is evaluated as a function of the number of crossed nodes in a mesh metro network, comparing VCSEL based transmitters performance also with the case of external electro-absorption modulator use. Finally, the maximum reach achieved based on the received optical signal to noise ratio (OSNR) and the fiber span length is discussed. The results confirm the possibility to use directly-modulated long-wavelength VCSELs for the realization of sliceable bandwidth/bitrate variable transmitters targeting 50-Gb/s capacity per polarization, also in the presence of 5 crossed WSSs for reaches of hundreds of kilometers in multi-span Erbium-doped fiber amplified (EDFA) metro links supported by coherent detection.  
Keywords:direct modulation; discrete multitone; metro networks; optical communications; vertical cavity surface emitting lasers +
Footnote †: journal:
# Enhancing Disease Diagnosis: Biomedical Applications of Surface-Enhanced Raman Scattering
## 5 Applications of SERS in Disease Diagnostics
### SERS in Breath Analysis
It is worth noting that SERS profiles were unaffected by age and gender of patients, illustrating the ability of SERS to overcome effects of between-patient confounding factors in routine clinical tests. A key prerequisite for successful SERS application in breath analysis is the design of optically sensitive probes that 'arrest' and provide a large surface area for adsorption of volatile metabolitessince VOCs diffuse quickly according to the Graham's law [142]. Several SERS substrates with improved capture properties have been proposed including bimetallic nanogaps [139; 143], dendritic nanocrystals [144] and 3D multilayered nanowires [143]. However, a SERS biosensor designed by [PERSON] et al. (Figure 4), where aggregated spherical Au superparticles (GSP) coated with ZIF-8 (so-called GSP@ZIF-8) formed a 3D core-shell to act as a SERS-active substrate and metal organic framework (MOF) that is quite attractive [145]. The notable merit of the GSP@ZIF-8 3D structure sensor is the ability to slow down the flow rate to promote adsorption, retention and equilibration of VOCs, resulting in increased enrichment and reproducibility. Clearly, GSP@ZIF-8 biosensor is more appealing and feasible for clinical analysis of specific lung cancer VOC biomarkers in real-time at the point of need. Recently, SERS has also become popular for the identification of validated headspace VOCs produced by specific invasive pathogens. Bacterial VOCs within exhaled breath or culture headspace are distinct, and their selective recognition serves as biomarkers for chronic illnesses [146]. The chemical structures and identities of a large number of microbial VOCs (mVOCs) biomarkers produced by human pathogens are available in mVOC database [147]. Hydrogen cyanide emitted by _Pseudomonas aeruginosa_ associated with cystic fibrosis [148], isovaleric acid for _Staphylococcus aureus_ and ethyl acetate and indole linked to sepsis [149], have all been detected and quantified accurately by SERS [150], to supplement recently published results using MS [151; 152]. Finally, SERS has been developed to probe the headspace of bacterial cultures to differentiate accurately viable cells from dead bacteria after treatment with the antibiotic gentamicin [153]. Henceforth, such VOC biomarkers will be identifiable in new patients with the same infections. It is very clear here that SERS offers dual benefits for healthcare: the rapid and sensitive detection of actual microbial pathogens and their phenotypic characteristics down to a single cell and the corresponding VOC molecular signatures as confirmatory results simultaneously. Figure 4: **(A)** Synthetic route for GSP@ZIF-8 3D core–shell. i. Aggregation of gold nanoparticles (AuNPs) to form spherical GSP. ii. GSP surface-coated with ZIF-8 shell. **(B)** Exhaled breath capture on GSP@ZIF-8 3D core–shell and detection of VOCs markers by SERS. Reproduced with permission from [PERSON] et al. [145]. Copyright © 2018, John Wiley and Sons.
# Research on Improving Satellite Positioning Precision Based on Multi-Frequency Navigation Signals
## 6 Conclusions  
Based on the existing equipment and technology of the CAPS system, this paper introduces a method to improve the positioning precision through multi-frequency navigation signals, which can effectively reduce the PDOP value and improve the positioning precision. In the simulation results of this paper, in the CAPS system, when the number of downlink multi-frequency navigation signals from each satellite is 12, compared with single-frequency navigation signals, the average PDOP value drops from 6.83 to 1.97, the positioning precision in two-dimensional space is improved by 67%. Because the test data is collected in the CAPS test phase, the positioning error is large and does not represent the final positioning precision of the system. In the GNSS system, when the number of downlink frequencies is 12, and when the daily average PDOP of the satellite constellation is basically kept at about 2, the PDOP value can be reduced to less than 1 through multi-frequency navigation signals, and the positioning precision in 3D space is improved by 71%; the standard deviation decreases with the increase of the number of frequencies, and the improvement effect of positioning precision and stability is obvious. This research provides theoretical support and data reference for future satellite positioning technology combining communication satellites and navigation and has theoretical research and application value.  
[PERSON] performed the data collections, software, formal analysis, visualization and writing the manuscript. [PERSON] performed the methodology, formal analysis, investigation and writing the manuscript. [PERSON] performed the conceptualization, investigation and writing the manuscript. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number U1931125.  
Not applicable.  
The authors declare no conflict of interest.
## 3 Results and Discussion
### Scenario IV: Longitudinal Distance between Two Valves L = 5D (10 m)  
Based on the results presented so far it can be stated that the hydraulic performance of the pipe in the case of using a distance of 8 m (\(L\) = 4\(D\)) compared to 6 m (\(L\) = 3\(D\)) can be significantly improved, resulting in a fully developed flow. In the scenario IV the difference in increasing this path it was considered by modeling similar conditions for a distance of 10 m (\(L\) = 5\(D\)) between the butterfly valve and the Howell-Bunger valve. Moreover, the optimal distance was selected. For this, the results of the numerical model simulation regarding the velocity distribution parameter in the area between the butterfly valve and the Howell-Bunger valve for a distance of 10 m (\(L\) = 5\(D\)), as depicted in Figure 12. Indeed, Figure 12 revealed that the distance of 10 m (\(L\) = 5\(D\)) between the butterfly valve and the Howell-Bunger valve can provide the fully developed flow conditions and the trend of changes in the velocity profile distribution at this point with the distance conditions of 8 m did not change noticeably. Therefore, flow velocity changes in this section can be considered the same at intervals of 8 and 10 m. In order to compare the turbulence energy conditions of the flow in the pipe, the results of the numerical model for this parameter have also been considered (Figure 12). Figure 12 showed that the amount of turbulent energy was completely dissipated after the flow passes through the butterfly valve in the pipe by creating a suitable distance from the Howell-Bunger valve, and the conditions were the same as that before the butterfly valve section in the pipe. The Such distance conditions prevalence between the two valves, they confirmed the correct hydraulic operation of the flow for a distance of 10 m between the valves. However, there was no significant difference between the results for two distances of 8 m and 10 m between the two valves. Thus, at a distance of 10 m, only thedistance of the formation of turbulent energy from the location of the Howell-Bunger valve can be safety considered.. In order to investigate the formation of vorticity due to the presence of a butterfly valve in the pipe, the numerical model results at the last two cases they were also investigated. The simulation results were extracted from the model, analyzed, and represented at Figure 12, revealing that the vortex due to (a) the presence of a butterfly valve in the pipe, (b) the distance of 10 m from the Howell-Bunger valve, it was at a completely stable condition and confirmed the development and non-formation of vorticity flow.
## 4 Discussion
For such cases, sampling frequencies of 1000 Hz and more are required and we have to look for the solution in combinations with hexadecimal representation and multiple samples in one packet. For example, if we use 10 samples per packet and a hexadecimal representation with bit-shift, we can easily achieve a sampling frequency of 1500 Hz. This would give us a delay at the receiver of less than 10 ms. Note that the described results represent the upper performance limit of the proposed scheduler on the current hardware configuration. Should we employ a faster processor, the scheduler's overhead remains constant in terms of CPU cycles, meaning that its relative computational load would be lower in percentage terms, thereby increasing processing capacity. In scenarios with additional sensors or computational tasks, the feasibility of maintaining real-time performance depends primarily on the available CPU power and memory capacity. However, since the scheduler itself does not introduce complex task management overhead, it remains a lightweight and scalable solution. When increasing the sampling frequency beyond 1750 Hz, potential bottlenecks arise primarily from sensor communication limits (e.g., P\({}^{2}\)C bus speed), data formatting overhead, and wireless transmission constraints, rather than from the scheduler. Optimizing hardware components--such as using a higher-clocked processor, faster memory access, or more efficient sensor interfaces--can extend the system's capabilities beyond the reported performance thresholds. We can assert that our findings apply to all wearable devices with similar architecture, where sensors are connected to a microcontroller and data packets are transmitted over a Wi-Fi interface. The relationships between sampling frequency, data format, and the number of samples per packet would remain consistent, with only the absolute values changing. While our scheduler was designed specifically for real-time biomechanical feedback applications, its simplicity makes it adaptable for other real-time data collection tasks. However, unlike a full RTOS, it lacks the task management and prioritization features required for complex, multi-threaded applications such as advanced robotics or large-scale industrial automation systems with numerous concurrent processes. For simpler applications, such as continuous sensor monitoring in industrial or environmental settings, the scheduler remains a lightweight and efficient solution.
# A Solar-Thermal-Assisted Adiabatic Compressed Air Energy Storage System and Its Efficiency Analysis
## 4 Results and Discussion
### Typical Operational Conditions
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**Stream** & **T** (\({}^{\circ}\)**C) & **P (MPa)** & **h (kJ/kg)** & **s (kJ/kg-K)** & **Ex (kJ/kg)** & **m (kg/s)** \\ \hline AR1 & 20 & 0.1 & 294 & 6.84 & 0.00 & 0.56 \\ AR2 & 150 & 0.3 & 425.14 & 6.88 & 120.73 & 0.56 \\ AR3 & 40 & 0.3 & 313.68 & 6.58 & 97.10 & 0.56 \\ AR4 & 178.5 & 1.0 & 453.71 & 6.61 & 226.56 & 0.56 \\ AR5 & 40 & 1.0 & 312.29 & 6.25 & 193.06 & 0.56 \\ AR6 & 181.4 & 3.3 & 455.14 & 6.28 & 325.42 & 0.56 \\ AR7 & 40 & 3.2 & 307.97 & 5.90 & 290.32 & 0.56 \\ AR8 & 179.5 & 10.2 & 449.22 & 5.93 & 421.51 & 0.56 \\ AR9 & 40 & 10.0 & 295.95 & 5.53 & 385.42 & 0.56 \\ AR10 & 20 & 6.9 & 278.93 & 5.58 & 353.63 & 0.56 \\ AR11 & 100 & 6.9 & 366.31 & 5.85 & 363.68 & 0.56 \\ AR12 & 280 & 6.7 & 557.59 & 6.27 & 430.60 & 0.56 \\ AR13 & 131.6 & 1.7 & 404.97 & 6.35 & 253.95 & 0.56 \\ AR14 & 280 & 1.7 & 558.59 & 6.68 & 311.16 & 0.56 \\ AR15 & 132.2 & 0.4 & 406.93 & 6.76 & 135.85 & 0.56 \\ AR16 & 280 & 0.4 & 558.92 & 7.09 & 192.53 & 0.56 \\ AR17 & 124.5 & 0.1 & 399.46 & 7.15 & 15.28 & 0.56 \\ AR18 & 34.5 & 0.1 & 308.59 & 6.89 & 0.35 & 0.56 \\ \hline \end{tabular}
\end{table} 
Table 5: Thermodynamic parameters of air stream. Figure 4 shows exergy destruction of the primary subsystem. In the STC system, the exergy destruction is 17.17% because of the substantial irreversible loss caused by external heat conduction, convection and radiation on the surface of the parabolic mirror and absorber tubes during the heat collection [31; 32; 33; 34; 35]. The STC requires a long time to heat the VP-1 from ambient temperature to the design temperature before operation. The exergy destruction of the system in this process does not take into account in the exergy analysis of ST-CAES. The HEX of TUR exergy destruction is the largest of all subsystem due to high temperature difference heat transfer, which caused an irreversible heat loss. To further clarify the performance of the proposed ST-CAES, a comparison of ST-CAES to an HA-CAES that integrated a gas turbine and dish collector in [23] is illustrated in Table 7. In the comparison case, the RTE and EXE for each system are 61% and 76.5%, and 50% and 53.4%, respectively. The inlet temperature of gas turbine is 900 \({}^{\circ}\)C due to being combined with dish collector and combustion chamber. Since these kinds of HA-CAES do not contain TES, output power of gas turbine fluctuates with changes in solar radiation. Although the RTE and exergy efficiency are higher than ST-CAES, such HA-CAES rely on fossil fuel supplies, which can cause certain carbon emissions. Compared with the above HA-CAES, ST-CAES with TES can provide a stable external heat resource, which can greatly improve the output power stability and operational flexibility.
# A Unified Denoising Framework for Restoring the LiDAR Point Cloud Geometry of Reflective Targets
## 1 Introduction
Unlike existing denoising algorithms that typically address only one type of noise, our method is capable of effectively tackling the veiling effect, range anomalies, and blooming effect within a unified framework, offering a comprehensive solution to the challenges encountered in complex scenarios. 2. By integrating the MSAC-based plane fitting algorithm with a ray-projection approach, the range-anomalous points are corrected back to the fitted plane. Compared with denoising algorithms based on spatial statistical strategies, which tend to treat these points as noise and remove them, our method recovers these points to the target's surface, resulting in a denser and more complete point cloud representation. 3. To the best of our knowledge, our method is the first to utilize the spatial energy distribution of Gaussian laser beams to eliminate noise points caused by the blooming effect. An adaptive error ellipse is used to refine the boundary of the blooming point cloud. The parameters of the error ellipse are adaptively determined based on the divergence angle of the laser beam, the target distance, and the normal vector along the boundary. With simple adjustments to the algorithm's parameters, it can be applied to various LiDAR models with different divergence angles. The rest of this paper is organized as follows: Section 2 provides a detailed introduction to the dataset and the proposed denoising framework. Section 3 presents the experiments and results, including experimental setup, evaluation metrics, and experimental results. Section 4 discusses the proposed algorithm, and the conclusions are summarized in Section 5.