esa-sceva/satcom-chunk-collection huggingface dataset:
# Adsorption of Hexavalent Chromium Ions Using Pine Sawdust Cellulose Fibres
###### Abstract  
In developing countries, agriculture generates not only income but also waste. Therefore, it is essential to recycle this waste for different purposes. This study explored an affordable way to modify pine sawdust to treat chromium-containing wastewater, with successful outcomes. The biosorbent's surface area was enhanced through pretreatment steps, including NaOH treatment, bleaching, and acid hydrolysis for cellulose fibre extraction. SEM-EDS, TEM, and XRD were used to study the chemical composition and morphology. XRD measurements also revealed a rise in the sizes of crystallites. FTIR results revealed shifts in bands (-OH), (-C)-H), and (-COOH), suggesting their involvement in Cr (VI) ion adsorption. TGA/DTA indicated enhanced thermal stability for cellulose extracted from pine sawdust compared to untreated pine sawdust. The adsorption parameters for Cr (VI) ions were investigated through mass, pH, stirring time, and temperature studies. The optimal Cr (VI) adsorption conditions were 2.0 g mass, pH 6, 90 min stirring, 100 mg/L concentration, and 313 K temperature. The adsorption of Cr (VI) ions was best-fit to the Langmuir isotherm model (R\({}^{2}\) = 0.9991, k\({}_{\text{L}}\) = 0.09). Pseudo-second-order kinetics (R\({}^{2}\) = 0.9999) provided the best description for Cr (VI) biosorption on cellulose fibres (CF). The analysis results confirmed the isotherm and kinetics models. The negative thermodynamic parameters (\(\Delta\)G\({}^{\circ}\) and \(\Delta\)H\({}^{\circ}\)) indicated that the uptake of Cr (VI) ions on the adsorbent was exothermic and spontaneous.  
sawdust; adsorption; chromium; cellulose fibres; error analysis; thermal analysis +
Footnote †: journal: _aciences_
# I/Q Imbalance and Imperfect SIC on Two-Way Relay NOMA Systems
## 1 Introduction
### Organization  
The rest of this paper is organized as follows. In Section 2, we describe the TWR C-NOMA system model in detail. In Section 3, the analytical and asymptotic been expressions of the outage probabilities, diversity order and the system throughput are obtained. Numerical examples of the derived analytical expressions and Monte Carlo simulations are given in Section 4. Finally, the conclusions are presented in Section 5.
# Data-Driven Analysis of Outdoor-to-Indoor Propagation for 5G Mid-Band Operational Networks
## 2 Background, Related Work, and Contributions  
This Section first provides an introduction on how channel propagation characteristics are often formalized mathematically, and on the beamforming strategies available in 5G NR. Next, it discusses relevant literature and finally highlights the contributions of the present paper.
## 3 Results
### Main Results Obtained
#### 3.2.2 Impact of Stimuli and Environmental Features  
Some studies (22.22%) aimed to explore the impact of the stimuli's eccentricity on memory performance [34; 39]. The results showed lower visuospatial memory performances at higher eccentricities compared to performances with smaller eccentricities, with no differences between smaller eccentricities [34]. Moreover, these differences were observed independently of whether the memory load of the task was low or high [34]. The study by [PERSON] et al. [39] explored the relationship between eccentricity, frames of reference, and navigation displacement in a spatial memory task. The results found that with a low eccentricity, there is a better performance with an egocentric frame of reference, independently of whether the navigation was active or passive [39]. In contrast, with high eccentricity, no differences between frames of reference were found, neither in active nor passive navigation [39].  
Also, 22.22% of the reviewed studies explored other stimuli features: the number of items to encode, maintain, and recall (i.e., memory load) as well as the size of items [34; 36]. Memory load was explored in the study by [PERSON] et al. [34], finding better visuospatial memory performances in lower memory loads. Regarding the size of the items, there was no effect of item size on performance in a visuospatial working memory task [36].  
The influence of environmental characteristics was studied on visuospatial working memory tasks, finding that neutral spaces and personally designed spaces enhanced the performance more than spaces generally preferred or non-preferred for the general population [35]. Furthermore, the study by [PERSON] et al. [36] explored if the addition of a background image could influence visuospatial working memory performance, compared to a black background, showing no differences between the two conditions.
## 3 Results
### Time  
Analysis showed significant differences in time (s) between the injection and peak pressure. The angles showed a significant effect (\(p<0.001\)), with mean (95% CI) times of 9.44 (from 8.06 to 10.66) s at 30\({}^{\circ}\), 10.66 (from 8.01 to 13.10) s at 45\({}^{\circ}\), and 6.53 (from 5.92 to 9.29) s at 60\({}^{\circ}\). The tissue type did not significantly affect the time (\(p=0.56\)). Planned comparisons within the tissue types also showed no significant differences in time. The Bonferroni multiple comparison test did not indicate significant time differences between the tissue types. Similarly, the Tukey-Kramer multiple comparison test did not reveal significant time differences between the tissue types. These findings suggest that while the angles significantly influence time, the tissue types do not significantly affect time during the injection procedures, as illustrated in Figure 5.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Technique** & **Pressure (SD)** & **Comparison** & **Difference** & \(p\)**-Value** \\ \hline Bolus injection & 38.4 (9.1) & Bolus vs. infusion & 2.6 (1.9–7.1) & 0.25 \\ \hline Continuous injection & 35.8 (19.7) & & & \\ \hline Angle & & & & \\ \hline
30\({}^{\circ}\) & 32.4 (12.3) & 30\({}^{\circ}\) vs. 45\({}^{\circ}\) & 2.0 (\(-\)5.0 to 9.0) & 0.77 \\
45\({}^{\circ}\) & 34.4 (17.7) & 30\({}^{\circ}\) vs. 60\({}^{\circ}\) & 12.2 (8.5 to 15.9) & \textless{}0.001 \\
60\({}^{\circ}\) & 44.6 (12.7) & 45\({}^{\circ}\) vs. 60\({}^{\circ}\) & 10.2 (3.2 to 17.2) & 0.02 \\ \hline Tissue & & & & \\ Muscle & 34.0 (14.5) & Epineurium—touch vs. muscle & 0.6 (\(-\)4.0 to 5.2) & 0.94 \\ Epineurium—touch & 33.4 (9.9) & Epineurium—indentation vs. muscle & 9.9 (2.3 to 17.4) & \textless{}0.007 \\ Epineurium—indentation & 43.9 (18.3) & Epineurium—indentation vs. touch & 10.5 (4.0 to 16.9) & \textless{}0.001 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of pressure and statistical analysis between bolus and continuous injection techniques at different angles and tissue locations.  
Figure 4: Image (**a**) shows differences in in-line pressure at different locations, but no trend. No difference between pressures at different locations. Image (**b**) shows increased pressure at 60\({}^{\circ}\) angle.
# Transimpedance Amplifier for Noise Measurements in Low-Resistance IR Photodetectors
## 5 Conclusions  
This paper presented the analysis, construction, and verification of an ultra-low-noise transimpedance amplifier. It was dedicated to investigating low-frequency noise in photodetectors, which are characterized by relatively low resistance, on the order of or below 1 k\(\Omega\). As discussed in this paper, a low-impedance device connected to the input of a transimpedance amplifier results in a large amount of background noise due to the equivalent input voltage noise source represented by the operational amplifier used in typical shunt-shunt feedback configurations. This problem was addressed and solved by designing a transimpedance amplifier based on a discrete device input stage-based operational amplifier, characterized by very low input voltage noise, on the order of 4 nV/\(\surd\)Hz, 2 nV/\(\surd\)Hz, and 0.9 nV/\(\surd\)Hz at 1 Hz, 10 Hz, and 1 kHz, respectively. The results were obtained by resorting to a low-noise IF3602 differential pair n-channel JFET transistor as a discrete input stage for the operational amplifier, which was used in a shunt-shunt configuration, in order to obtain a transresistance stage. The resulting background noise was investigated and verified using known-value resistors as DUTs. After preliminary characterization, the amplifier was used to study the current noise in a low-resistance InAsSb barrier detector, demonstrating that direct and reliable measurement of the current noise in low-impedance devices is indeed possible with the instrumentation designed and tested here.  
Conceptualization, K.A., C.C. and G.S.; methodology, K.A. and G.S.; software, K.A.; validation, C.C., J.M., Z.B. and G.S.; formal analysis, J.M., Z.B., C.C. and G.S.; investigation, K.A.; data curation, K.A.; writing--original draft preparation, K.A.; writing--review and editing, G.S., J.M., C.C. and Z.B.; supervision, C.C. and Z.B. All authors have read and agreed to the published version of the manuscript.  
This work was funded by Military University of Technology grant no. UGB-22-871.  
Not applicable.
## 2 Materials and Methods
### Duty Cycle Measurement  
#### 2.2.1 Equipment and Configurations  
Figure 1 shows the setups for the Wi-Fi 6 exposure measurements. The DC was measured using a Rohde & Schwarz FSV3030 SA connected with a Clampco AT6000 three-axis isotropic antenna (frequency range of 400 MHz to 6 GHz, with a maximum accepted electric field strength of 300 V/m). The antenna's axis selection was achieved via an internal electronic switch controlled by the ATSA04 axis controller through a coaxial cable. The measurement system has an uncertainty of \(\pm\)3 dB. The SA parameter settings were configured following the recommendations of [8] for Wi-Fi DC time-domain measurements, and the detailed parameters are listed in Table 4. The zero-span mode was used to record Wi-Fi 6 time-domain signals in spectrogram form. Since DC measurement focuses solely on the temporal distribution of signals, only the power density along a single axis was recorded.  
Figure 1: The measurement setup and layout for the single-user scenario. (**a**) Three-axis antenna was placed at the UD side. (**b**) Three-axis antenna was placed at the AP side. (**c**) The overall layout of the measurement setup, and the three-axis antenna was placed at the center.  
\begin{table}
\begin{tabular}{l l} \hline
**User Device** & **Model** \\ \hline Mobile phone & iPhone 14 Pro \\ Tablet & Samsung Galaxy Tab S8+ \\ Laptop & Dell Latitude 5430 \\ USB Wi-Fi adapter & Asus USB-AX56 Dual-band \\ \hline \end{tabular}
\end{table}
Table 3: User devices used in this work and their models.
###### Abstract
Therefore, most communication systems are equipped with a large number of electronic components in their small internal space, which increases the computing load under the conditions of system miniaturization, and the method of designing an appropriate heat dissipation mechanism will affect the stability and efficiency of the device. To solve the aforementioned problem, the purpose of this study was to optimize the design of the cooling system in the T/R modules of communications systems by integrating heat pipes, cooling fans, cooling fins, and cooling chips within a limited space. In addition, based on the different directional clamp-in configuration methods of heat pipes within copper panels, we designed four types of cold plates and utilized the finite element method (FEM) to simulate and analyze the heat dissipation performance of all cold plates. The simulation results reveal that type I and II cold plates can achieve a better heat dissipation performance. Finally, these types (I and II) were selected for production and experimental verification. The results show that heat dissipation performances were similar to simulation results. The results also verify that type II has a better temperature uniformity and heat transfer efficiency. This is evident that the cooling mechanism described in this study is viable for practical applications. The proposed mechanisms can also provide a reference for heat dissipation design patterns in different electronic module settings. In addition, the same products with narrow, closed, and non-convective internal space features include defense weapon system millimeter-wave radar, missile system guidance, control section core computing unit, 5G communication system, high-speed computing workstation/server, etc. Through the active heat dissipation configuration of the structure of this experiment, the relevant adaptive design is carried out to achieve the temperature range control and meet the heat dissipation requirements of the system.
## 2 Materials and Methods
### Data  
A total of forty years (from 1980 to 2019) was selected as the study period. Three decades are recommended by the World Meteorological Organization (WMO) to carry out climatic studies. We initially worked with a database of 350 meteorological stations containing monthly average temperature data available on the Western Regional Climate Center (WRCC) website [49]. The meteorological stations were selected considering criteria of completeness, length and homogeneity to cover most of the state [50]. Only stations with less than 10% of missing values were chosen. Those missing gaps were completed with the corresponding monthly long-term mean value [51].  
Homogeneity analysis of the series was also carried out. In this study, it was determined by the Run test [52], with a confidence level of 99%. This test is recommended by the World Meteorological Organization (WMO) because it does not require the analysed series to come from a normal sample and it has also been previously used by other climatic studies [53; 54]. After the elimination of the meteorological stations with missing data and homogeneity analysis, we finally worked with 170 stations (Figure 1). The altitude values and geographic coordinates of each of the stations used were also added to the database to ease the representation of the results obtained on maps at a later date.  
Monthly values were averaged for each meteorological station to obtain seasonal and annual series. In California, 4 seasons are considered: Winter (December, January and February), spring (March, April and May), summer (June, July and August) and autumn (September, October and November). From now on, the seasons will be named DJF, MAM, JJA and SON, respectively.  
For the whole State of California, the monthly, seasonal and annual temperature was computed using Voronoi polygons weighting temperature stations by the area of each polygon [55].
## 1 Introduction
[25] simplified the Janbu method to make it more suitable for calculating the safety factor of three-dimensional slopes. [PERSON] and [PERSON] [26] established a three-dimensional limit equilibrium model based on the Hoek-Brown criterion to evaluate the stability of three-dimensional rock slopes, thus expanding the research field to rock slopes. [PERSON] et al. [27] systematically and comprehensively expounded and demonstrated the application of the three-dimensional limit equilibrium method in slope engineering through specific research cases. [PERSON] and [PERSON] [28; 29] were the first to analyze the stability of vertical angular notches subjected to local additional loads using the upper-bound method, but they did not deeply analyze the failure surface forms under different slope angles. Some scholars from other countries have also carried out analyses using the finite element method. For example, [PERSON] and [PERSON] [30] used the finite element method to verify an improved limit equilibrium method incorporating stress acceptability criteria, making the simulation of the failure mechanism of the slip surface more accurate. [PERSON] et al. [31] proposed the 3D Key-Group Method for three-dimensional slope stability analysis and established a rigid-body plastic limit equilibrium equation considering three-dimensional effects, but its adaptability to complex boundary conditions is limited. Although many scholars have analyzed the mechanical characteristics and fracture modes of soil nailing walls and supports from different angles, the rationality and reliability of the existing fracture surface forms have rarely been studied from the perspectives of energy methods and plastic mechanics. These aspects have an important influence on the design length of soil nailing support structures with different slope angles and different soil internal friction angles. In this study, first, a theoretical analysis model of an inclined plane is established based on the reinforcement mechanism of soil nailing support to verify the rationality of the conservation of energy. Second, a theoretical analysis model of the fracture surface form considering the tension depth at the top is established, and the mathematical expressions of the fracture surface form in terms of _h/H_ and _L/H_ are derived based on the plasticity theory. Finally, based on different slope foot and internal friction angles, the fracture surface forms are discussed. The results are compared with the methods available in the literature. The results provide important insights for understanding the mechanism and mechanical characteristics of soil nailing support at a deeper level and improving its design method. The results also provide significant guidance for the application of soil nailing supports in engineering practices.
# Preventive Maintenance Decision-Making Optimization Method for Airport Runway Composite Pavements
###### Abstract  
Long-term preventive maintenance planning using finite annual budgets is vital for maintaining the service performance of airport runway composite pavements. Using the pavement condition index (_PCI_) to quantify composite pavement performance, this study investigated the _PCI_ deterioration tendencies of middle runways, terminal runways, and taxiways and developed prediction models related to structural thickness and air traffic. Performance jump (_PI_) and deterioration rate reduction (_DRR_) were used to measure maintenance benefits. Based on 112 composite pavement sections in the Long-term Pavement Performance Program, this study analyzed the influences of five typical preventive maintenance technologies on _PI_, _DRR_, and _PCI_ deterioration rates. The logarithmic regression relationship between _PI_ and _PCI_ was obtained. For sections treated with crack sealing and crack filling, the _DRR_ was nearly 0. For sections treated with fog seal, thin HMA overlay, and hot-mix recycled AC, the _DRR_ was 0.2, 0.7, and 0.8, respectively. To solve the multi-objective maintenance problem, this study proposed a decision-making optimization method based on dynamic programming, and the solution algorithm was optimized, which was applied in a five-year maintenance plan. Considering different _PCI_ deterioration tendencies of airport regions, as well as _PI_, _DRR_, and costs of maintenance technologies, the preventive maintenance decision-making optimization method meets performance and financial requirements sufficiently.  
composite pavement; performance prediction model; preventive maintenance; decision-making optimization method; dynamic programming  
14380. [[https://doi.org/10.3390/app14093850](https://doi.org/10.3390/app14093850)]([https://doi.org/10.3390/app14093850](https://doi.org/10.3390/app14093850))  
10.3390/app14093850
# Lip2 Speech: Lightweight Multi-Speaker Speech Reconstruction with Gabor Features
## 6 Results
### Multi-Speaker Model Results
Subplots (1)–(4) show the average accuracy (Corr2D), PESQ score, objective overall speech quality (OOSQ), and STOI measurement of the reconstructed speech  
and waveforms using our proposed GaborFea2 Speech model in 1-S, 2-S, 4-S, 6-S, and 8-S scenarios, Figure 15b(1)-b(5) shows the equivalent for our proposed GaborCNN2 Speech model, and Figure 15c(1)-c(5) shows Lip2 AudSpec visualisations. Figure 15 demonstrates that with our multi-speaker dataset, the proposed GaborFea2 Speech model exhibits minimal sensitivity to the number of speakers when reconstructing spectrograms and waveforms, meaning that it is more suitable for multi-speaker speech reconstruction. GaborCNN2 Speech is moderately affected by the number of speakers, but the baseline Lip2 AudSpec model is heavily influenced by the number of speakers and is unable to reconstruct multi-speaker speech. Figure 15a(1)-a(5) shows that GaborFea2 Speech consistently and accurately reconstructs a significant portion of frequency content with excellent temporal continuity and phonetic accuracy as the number of speakers increases. Moreover, the reconstructed waveforms from GaborFea2 Speech showcase high amplitude precision and minimal sensitivity to the number of speakers. GaborCNN2 Speech exhibits partial reconstruction of frequency  
Figure 15: Reconstructed spectrogram and waveform comparison for Speaker S27. **i(0)**: original spectrogram and waveform of “bin blue by f 8 now”. **(a(I))–a(5)**): reconstructed spectrograms and waveforms for GaborFea2 Speech with 1-S, 2-S, 4-S, 6-S, 8-S datasets. **(b(1)–b(5))**: equivalent GaborCNN2 Speech results. **(c(1)–c(5))** equivalent Lip2 AudSpec results. content in spectrograms and amplitude information in waveforms when the number of speakers is low (Figure 15b(1)-b(3)). However, as the number of speakers increases, its reconstruction performance gradually declines. At six speakers, GaborCNN2 Speech only captures the temporal continuity of phonetic samples, losing a significant amount of frequency content and amplitude information (Figure 15b(4)). The accuracy further decreases with eight speakers (Figure 15b(5)). In contrast, the Lip2 AudSpec results in Figure 15c(1)-c(5) exhibit the poorest performance in multi-speaker speech reconstruction. It should be noted that with eight speakers, the model loses almost all frequency content and amplitude information, resulting in effectively random reconstruction of noise-related information.