esa-sceva/satcom-chunk-collection huggingface dataset:
# Research and Progress on Truing and Sharpening Process of Diamond Abrasive Grinding Tools
## 3 Dressing Method of Diamond Abrasive Grinding Tools
### Sharpening Technology of Diamond Abrasive Grinding Tools
#### 3.2.1 Free Abrasive Grain Sharpening Method  
The free abrasive grain sharpening method mainly includes ultrasonic vibration sharpening, free abrasive jet sharpening, and free abrasive extrusion sharpening. Among these, the free abrasive jet sharpening method is a high-efficiency sharpening method, which can obtain an ideal sharpening effect in a short time. [PERSON] et al. [31] proposed a dressing method combining grinding grains extrusion and dressing under the constraint of a diamond surface and found that this method could enable rapid forming and precision dressing of super-hard abrasive grinding wheels. When selecting appropriate parameters, such as the grinding force and grinding ratio, the dressing efficiency was approximately 23\(\sim\)30%.  
To improve the surface topography characteristics of abrasive tools and achieve the purpose of dressing, numerous researchers have used the ultrasonic vibration sharpening method in combination with other methods. [PERSON] et al. [32] studied the ultrasonic vibration dressing method and analyzed the influence of the cutting ratio on the diameter error in ultrasonic vibration-assisted turning. [PERSON] et al. [33] carried out a laser ultrasonic vibration collaborative dressing experiment on diamond abrasive grinding wheels and studied the removal behavior of laser-assisted ultrasonic dressing of diamond abrasive grinding wheel material through simulation and experimental methods. The experiments showed that the simulation results could be used effectively for the selection of process parameters. The abrasive grains had an ideal shape and protrusion in this dressing mode, and the grinding wheel had a large chip holding space.  
The efficiency of dressing diamond abrasive grinding tools by the free abrasive grain sharpening method is low, so it has not been popularized and applied in industrial production. However, the integration of the ultrasonic vibration sharpening method and other dressing methods is still a worthwhile research direction for future dressing technology.
## 4 Numerical Modeling
### Momentum Source Model  
For the momentum source model, illustrated in Figure 7, the impeller is replaced by a disc. In the disc region, a source term, represented by Equations (8)-(11), is imposed on the momentum equation to mimic impeller rotation. Since the mesh is completely fixed in this model, i.e., without regions with imposed rotation, the computational cost is significantly lower than that required for a rotation region. It is also possible to further reduce the computational cost by considering it as a symmetry condition problem so that it can be simulated with just a quarter of the computational domain.
# OTFS-IM Modulation Based on Four-Dimensional Spherical Code in Air-to-Ground Communication
## 5 Conclusions  
In this paper, we investigated the OTFS-IM system based on the four-dimensional spherical code to enhance the performance by utilizing the advantage of the increased distance between constellation points in higher dimensions. On the one hand, achieving the requirement of BER at a lower signal-to-noise ratio is conducive to reducing power consumption and improving the endurance of UAVs in A2G communication. On the other hand, the scheme proposed in this paper to improve the performance is more concise and convenient; it does not increase the number of steps of the transmitter in the same way as most existing studies, i.e., by increasing the index dimension. Moreover, we analyzed the performance of a practical OTFS-IM4 system, which includes the analysis of the approximate value of the BER and the upper bound of the PAPR. It is worth noting that there is a trade-off between spectral efficiency and PAPR due to the different activation proportions in the sub-blocks. The simulation results demonstrate that our proposed OTFS-IM4 system is capable of providing more than 1 dB performance gain over the traditional OTFS-IM with two-dimensional modulation. It is proved that the proposed system has stronger robustness and generality. Furthermore, our theoretical derivations  
Figure 7: The CCDF comparison of different schemes: (**a**) \(N=16\), (**b**) \(N=32\).  
for OTFS-IM4 are also verified by simulation results, which theoretically supports the proposed system's performance. It is also worth noting that, in the future, research can be conducted to further explore four-dimensional spherical code and better-performing equalization techniques, such as an iterative MMSE method [32].  
Conceptualization, J.Z.; methodology, L.G.; software, P.G.; validation, G.L., S.J. and J.Z.; formal analysis, L.G.; investigation, P.G.; writing--original draft preparation, P.G.; writing--review and editing, L.G.; supervision, G.L. and J.Z. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the technology project of State Grid (5700-202214478A-2-0-KJ).  
Not applicable.  
The authors would like to thank the editor and the anonymous referees for their instructive comments.  
The authors declare no conflict of interest.
## 3 Results and Discussion
### Optimization of Single Extraction Condition
#### 3.3.2 Effect of Extraction Time  
From Figure 5b, when the extraction time was increased from 20 to 30 min, the yields of CPT, HCPT, VCS-LT, and EOs increased greatly. However, when the time was more than 30 min, the yields of CPT, HCPT, VCS-LT, and EOs decreased slightly. This is probably because prolonged heating leads to thermal decomposition of the three non-volatile target compounds and volatilization of the EOs, leading to the decreased yields [49]. Based on these results, 30 min was used for subsequent experiments.
## 1 Introduction
The numerical solution for governing equations of motion can be obtained through Finite Difference Methods (FDMs), Finite Element Methods (FEMs), Finite Volume Methods (FVMs) [28; 29; 30; 31; 32], and meshless methods [33; 34]. The same scenario analyzed here of a dam-break caused by a partial failure of the dam over a fixed bed has been simulated with different numerical methods by several authors (e.g., [35; 36; 37; 38]). These authors have also considered movable bed conditions [39; 40]. However, and differently from the present work, all of them considered a dry bed downstream of the gate and an open boundary at the end of the channel, thus ignoring wave reflections at the end wall. An accurate description of dam-breaking during the initial stages of motion can be well represented by solving the fully 3D Navier-Stokes equations (NSEs), or, similarly, by solving the Reynolds-Averaged Navier-Stokes (RANS) equations, coupled with a turbulence model [41] as done in the present work [42; 43; 44; 45; 46; 47; 48]. Dam-break problems are usually mathematically modeled by simplified 1D and 2D models and, most of the time, by Shallow Water Equations (SWEs) derived from depth-integrating the 3D continuity and momentum equations. SWEs are, in fact, valid where the vertical length scale is negligible compared to the horizontal one (such that the vertical component of the fluid velocity is insignificant and the vertical pressure gradient is hydrostatic), and presents the advantage of providing valuable results while requiring considerably less computational time than 3D models for large computational domains [2; 12; 49; 50; 51; 52; 53]. SWEs' approximation of depth-averaging velocities and accelerations is usually acceptable, except when either the flow has rapid changes in the horizontal and vertical directions and in the early stages following the dam-break [14; 54; 55; 56; 57]. In the short time step immediately after the gate collapse, in fact, flow is mainly influenced by the vertical acceleration due to gravity and the gradually-varied flow hypothesis does not hold. In this paper, in contrast to most of the previous investigations, the 3D propagation of a partial dam-break wave in an enclosed domain over initially dry and wet beds with two different tailwater levels was experimentally and numerically investigated. Image processing was adopted as a measuring technique, and, specifically, ultrasonic sensors were used to obtain stage hydrographs at five different locations. Numerical simulations were performed by the Computational Fluid Dynamics (CFD) software package of FLOW-3D [25], with the SWEs, RANS equations, and a standard \(k\)-\(\varepsilon\) model [41] as closure equations. Comparing the experimental measurements against the numerical simulation results obtained with both methods allowed for the drawing of some interesting conclusions.
## 2 Materials and Methods
### Color Stability of Materials in Different Solutions  
In the first part of the study, three different biomaterials (Biodentine, Angelus MTA, and BIOfactor MTA) and three different irrigation solutions (2% chlorhexidine gluconate, 2.5% sodium hypochlorite, and distilled water) were used. Biodentine, Angelus MTA, and BIOfactor MTA were mixed homogeneously as the manufacturer recommended and put into 8 mm diameter by 2 mm height Teflon cylindrical models. The samples were stored at a 37 \({}^{\circ}\)C and 100% humidity level while the materials reached their ideal mechanical characteristics. Color measurements on both sides of the samples were performed after each sample was removed from the mold. Six samples from each group were prepared and left in each of the 3 irrigants for 24 h (n = 2). Following this period, the samples were dried and the colors of the two sides of each sample were measured. The same operator measured the color under steady lab lighting using a spectrophotometer (VITA Easyshade Advance; Vita Zahnfabrik, Bad Sackingen, Germany). Before each measurement, the instrument was calibrated three times. Color differences (\(\Delta\)E) were computed using the Commission Internationale de I'Eclairage (CIE) system L * a * b * values using the following formula:  
\[(\Delta\)E\()L^{*}a^{*}b^{*}=[(\Delta\)L\()^{2}+(\Delta\)a\()^{2}+(\Delta\)b\()^{2}]1/2\]
## 1 Introduction
Such projects are prohibitively expensive and refer to extensive public use while not being suitable for individual domestic investment [15, 16]. By considering all the above issues arising from the use of the widely accepted renewable energy sources when they constitute off-grid electric charging stations, an innovative power supply method is revealed by the use of the inexhaustible deposits of natural gas. The core idea here is to take advantage of the already-established natural gas network in order to use CH\({}_{4}\) not only to produce thermal energy for domestic use but also to electrify a light commercial EV on a daily basis [17]. As is already known, a fuel cell stack fed by hydrogen-rich gases, can constitute the main component of a system for electricity production purposes. The best known and most widely quoted fuel cells (FCs) are the polymer electrolyte membrane (PEM) and Solid Oxide Fuel Cell (SOFC), preferred for portable and stationary applications, accordingly [18, 19]. Specifically, PEM FCs are more sensitive to humid conditions and to the purification of the hydrogen. Also, these are significantly influenced by the fuel impurities and by the carbon monoxide produced during the reforming process, while characterized by the high maintenance costs of the membrane's replacement [20, 21]. On the other hand, SOFC-stack, which seems more promising for the present project, can by supplied by different mixtures of gases, such as natural gas, without influencing its efficiency, mainly due to the elevated temperatures at which they operate [22, 23]. In the present project, an intermediate temperature SOFC (IT-SOFC) is simulated in order to prevent the additional cost for heat energy demands during the system's operation. These FCs seem to be more profitable under a moderate temperature range of 400-700 \({}^{\circ}\)C [24; 25]. The core question raised in the discussion of all the above considerations is whether a reliable green energy source exists for everyday use under a domestic establishment, to charge an EV 24 h a day and 7 days a week permanently, without significant issues. At this point, we present an innovative SOFC-based home charging system, fed by natural gas (i.e., directly connected to the national gas supply grid), in order to utilize the methane-rich gas to feed a SOFC-stack for electricity production to cover the needs of a family's EV.
## 3 Reactive Power Optimization Method Based on Graph Security Reinforcement Learning  
### Security Graph DDPG Algorithm  
The conventional DDPG algorithm employs random exploration during training to expand the search space. However, in the context of voltage control, the actions taken by the agent are directly applied to the distribution network, which may lead to safety issues such as voltage violations. Therefore, it is necessary to further constrain the actions output by the agent's policy network. This paper proposes an improved approach by incorporating a constraint critic network into the deep policy network. The constraint critic evaluates the safety cost of the actions generated by the actor network and restricts them within a low-cost region, enabling the agent to accumulate experience that adheres to safety constraints during training. The neural network architecture of the proposed algorithm is illustrated in Figure 4 and a detailed description of SGDDPG is shown in Algorithm 1.  
Figure 4: The structure of the safe-DDPG algorithm.  
Figure 3: Illustration of the agent–environment interaction process.  
```
0: Hyperparameters: EPISODES, STEPS, TEST, LR_ACTOR, LR_CRITIC, dual_variable, dual_variable_lr, obs_dim, act_dim, memory_capacity, batch_size, var, \(\gamma\), \(\tau\), constraint_limit
1: Initialize Actor network \(\pi\) and Reward Critic network \(Q_{\omega_{R}}^{R},Q_{\omega_{C}}^{C}\)
2: Initialize target networks \(\pi^{\prime}\) and \(Q_{\omega^{\prime}_{R}}^{R},Q_{\omega^{\prime}_{C}}^{C}\)
3: Initialize replay buffer \(\mathcal{B}\)
4: Initialize dual variable \(\lambda=0\)
5: Trained Actor network \(\pi\)
6:for episode = 1 to EPISODES do
7: Initialize environment and obtain initial state \(s_{0}\)
8:for step = 1 to STEPS do
9: Select action \(a_{t}=\pi(s_{t})\)
10: Execute action \(a_{t}\), observe reward \(r_{t}\), cost \(c_{t}\), and next state \(s_{t+1}\)
11: Store transition \((s_{t},a_{t},r_{t},c_{t},s_{t+1})\) in \(\mathcal{B}\)
12: Update current state \(s_{t}\gets s_{t+1}\)
13:if episode \(>\) memory_warmup_steps then
14: Sample random mini-batch of transitions from \(\mathcal{B}\)
15: Update Reward Critic network by minimizing loss in Equation (12)
16: Update Cost Critic network by minimizing loss in Equation (14)
17: Update Actor network by ascending \(\
abla_{\theta_{\pi}}\mathbb{E}[Q(s,\pi(s))]\)
18: Soft update target networks:
19:\(\Psi^{\prime}\leftarrow\tau\;\Psi+(1-\tau)\Psi^{\prime}\)
20:\(\omega^{\prime}_{R}\leftarrow\tau\;\omega_{R}+(1-\tau)\omega^{\prime}_{R}\)
21:\(\omega_{C}\leftarrow\tau\;\omega_{C}+(1-\tau)\omega^{\prime}_{C}\)
22: Update dual variable \(\lambda\) based on constraint violation
23:endif
24:endfor
25: Evaluate the performance of the current policy
26:if performance meets criteria then
27: Save the current Actor network parameters
28:endif
29:endfor
```  
**Algorithm 1** Safe graph DDPG algorithm.
###### Abstract  
This study aims to investigate the impact of a self-developed environmentally friendly composite dust suppressant on soil properties, with the objective of addressing dust pollution at construction sites. A series of experiments were conducted to examine the effects of the composite dust suppressant on soil strength (including compressive strength, shear strength, and surface hardness) and wind erosion resistance. The results demonstrate that spraying the soil with the composite dust suppressant diluted 10 times not only significantly enhances the compressive strength and ductility of the soil but also reduces the usage cost. Furthermore, the soil treated with the diluted suppressant exhibited the highest ultimate compressive strength after drying for seven days, which was 118.1 kPa higher than that of the undiluted treatment. The shear strength test also revealed a substantial increase in the shear strength of the soil treated with the dust suppressant under different vertical loads. Hardness tests showed that the composite dust suppressant containing binder significantly improved soil hardness. Wind erosion resistance tests further confirmed that the soil sprayed with the composite dust suppressant had a mass loss rate of only 9.36% within twenty minutes under an eleven-grade natural wind force, demonstrating good wind erosion resistance. This study not only provides a scientific basis for assessing the environmental impact of environmentally friendly composite dust suppressants on soil but also offers standardized evaluation techniques and experimental protocols for practical applications of dust suppressants.  
compressive strength; shear strength; surface hardness; wind erosion resistance Article
# Duality of Biochar and Organic Manure Co-Compositing on Soil Heavy Metals and Enzymes Activity
## 2 Materials and Methods
### Soil Metal and Nutrient Analysis  
An inductively coupled plasma-mass spectrometer (ICP-OES, Perkin Elmer, Shelton, CT, USA) was employed to analyze the concentrations of Cd, Cr, Ni, Pb, Zn, Cu, and Mo following the U.S. EPA method 6020a [37]. Spike recovery rates ranged from 85% to 100%, with a relative percentage difference of less than 3% for repeated analyses. The \(m/z\) values for quantification were 52 for Cr, 60 for Ni, 65 for Cu, 66 for Zn, 98 for Mo, 112 for Cd, and 208 for Pb. The native soil utilized in this study consisted of approximately 56% silt, 38% clay, and 6% sand, with a pH of 6.2, a CEC of 14.7 meq100 g\({}^{-1}\), and an OM content of 2.2%. Nutrient levels included total N at 0.18%, N-NO\({}_{3}\) at 20.7 ppm, N-NH\({}_{4}\) at 5.7 ppm, P at 95.8 ppm, K at 336.2 ppm, and C at 1091 ppm. A Fisher brand XL500 Benchtop Meter (Thermo Fisher, Waltham, MA, USA) equipped with Orion High-Performance ammonia and nitrate electrodes was used to measure NH\({}_{4}\) and NO\({}_{3}\), adhering to APHA guidelines [38]. The pH value was determined using a distilled water slurry of 1:5 (\(w/v\)), EC was measured using an electrical conductivity meter (Multi 3430 WTW unit, Weilheim, Germany) and C was measured using an ICP-OES spectrometer. One-way ANOVA was applied to analyze heavy metals, NH\({}_{4}\), and NO\({}_{3}\) in soil and animal manure amendments [39], complemented by [PERSON]'s multiple range test to compare means.
## 1 Introduction
Two anodes with the same Ni fraction were prepared by electrospinningning and power processing, respectively. The test results showed that the peak power density of the cell with the electrospun anode is twice that obtained using the power-processing anode, which was attributed to the longer TPB of the former anode. [PERSON] et al. [33] compared La\({}_{0.8}\)Sr\({}_{0.2}\)Co\({}_{0.2}\)Fe\({}_{0.8}\)O\({}_{3-6}\) (LSCF) nanorod/Ce\({}_{0.8}\)Gd\({}_{0.2}\)O\({}_{1.9}\) (GDC) nanoparticle composite cathode with LSCF/GDC nanoparticle cathode. The polarization resistance of the former is five times smaller than that of the latter. Further studies indicated that the cathode performance is better when the diameter of the nanofibers is sufficiently small [33; 35]. Other studies [36; 37] confirmed the significant influence of the microstructure and intrinsic properties of the basic components on the cathode performance. Although the CE and IE have been widely studied, the electrospun electrode (EE) morphology differs from that of the CE or IE. The models and results for the CE and IE cannot be directly applied to the EE. The 3D reconstruction via FIB-SEM or X-ray diffraction is a powerful tool to quantitatively analyze the geometric properties of CEs. However, those methods cannot be used to reconstruct the impregnated microstructure due to the resolution gap [31]. Therefore, although the experimental activities are strong, as aforementioned, most experiments focused on the preparation and testing of the macro-performance; quantitative analyses of the geometric properties are rare. Contrary to in-depthexperimental studies, there is little theoretical research, to the best of our knowledge. The work of [PERSON], [PERSON] and [PERSON], [PERSON] [38] was developed specifically for LSCF fibers. Being LSCF a MIEC (mixed ionic electronic conductor, embedding both electronic and ionic conduction simultaneously), a number of infiltrated particles below the percolation threshold were considered. Conversely, in the present work, the fibers are considered to be a pure ionic conductor, and percolation of the infiltrated electronic conducting particles is a mandatory feature for the electrochemical reaction to expand into the electrode bulk, i.e. for the infiltration/fiber interface to contribute to the TPB. In this paper, based on the microstructure of EE reported in literatures [18; 19] and the percolation threshold, a theoretical model was developed for the EE by comparing the EE to fibers with surfaces that were coated with impregnated particles. This model captures the key geometric parameters and their interrelationship, which can be used to derive explicit expressions of several key electrode parameters. Furthermore, the TPB length of the EE was calculated based on this model. Finally, the effects of the particle radius, fiber radius, and impregnation loading were systematically studied.