esa-sceva/satcom-chunk-collection huggingface dataset:
## 5 Conclusions  
A theoretical discrimination method for the WFZDH based on thin-plate theory was proposed following a study of the 1301 working face at Yeping Coal Mine. The following conclusions were drawn:  
1. Key stratum failure needs to satisfy two conditions: the suspended span of the key stratum must be greater than the critical span at which the key strata first fracture, and the free space height below the key stratum must be greater than its maximum deflection. The deflection variation of the key stratum before its initial failure was analyzed, as well as the relationship between the suspended span of the key stratum and the advancement distance of the working face. Based on thin-plate theory, the theoretical discrimination method for the WFZDH was proposed.  
Figure 14: Borehole 1 overburden fracture development: (**a**) borehole depth 24 m; (**b**) borehole depth 30 m; (**c**) borehole depth 36 m; (**d**) borehole depth 45 m; (**e**) borehole depth 63 m; (**f**) borehole depth 72 m.  
According to the geological information at Yeping Coal Mine, the proposed theoretical discrimination method was applied to calculate the WFZDH development in the 1301 working face. The field measurement results are similar to theoretical discrimination method, which verifies the reasonableness and practicability of the discrimination method.
3. The method only requires knowledge of the geological information above the working face and a simple calculation can be used to obtain the WFZDH. However, this method does not consider the influence of factors such as possible pre-existing fissures in the overlying rock layers on the WFZDH, and there will be a certain degree of error between its calculation results and the actual values. At the same time, this research has some limitations, and it is mainly for the first mining or a single working face. Further research is needed on the WFZDHs for subsequent working faces and after multiple working faces have been mined.  
[PERSON] and [PERSON] conceived and designed the study. [PERSON] and [PERSON] were involved in theoretical modeling and analysis. [PERSON] was involved in the Field measurement and prepared all figures. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Natural Science Foundations of China (Grant No. 52174138).  
Not applicable.  
All data used to support the findings of this study are available from the corresponding author upon request.  
The authors acknowledge the support of [PERSON] and [PERSON], who collaborated in the research.  
The authors declare no conflicts of interest.
# Backscatter Communications: Inception of the Battery-Free Era--A Comprehensive Survey
## 5 BackCom: Wireless Communications
### Multiple Access Techniques for BackCom
#### 5.3.4 Non-Orthogonal Multiple Access (NOMA)  
NOMA is treated as the crucial enabling technique with channel gain variations. Various users are multiplexed in the transmission power and could be scheduled non-orthogonally. These multiplexed signals are transmitted on the same spectrum sources. [PERSON] et al. discussed and analyzed the working principles of the uplink and downlink of NOMA [106]. The authors further described distinct working principles for the downlink and uplink using NOMA transmissions in wireless cellular systems. Furthermore, total throughput maximization problem in a cell was formulated, so that user clustering and power allocations conceivably optimize power constraints. NOMA was used for data transfer in BackCom and was shown to have better spectral efficiency and user equity [101]. Figure 28 shows the block structure of WPCN using NOMA. The block is divided into two parts: (i) a data backscattering period \(t_{1}\) and (ii) a transmission period \(t_{2}\). In the data backscattering period, the user \(U_{i}\) reflects/backscatter data to the information receiver during its designated time slot \(\alpha_{i}\), whereas all other users harvest energy from the source. Similarly, authors investigated the system level performance of NOMA with successive interference canceller (SIC) on the receiver side [105]. Likewise, the sparse-coded Amb-BackCom modulation algorithm allowed for NOMA in addition to M-ary modulation for concurrent transmissions [119]. NOMA-assisted monostatic BackCom was highlighted by [PERSON] et al. [120]. BackCom nodes, having different power levels, could be paired by the reader to implement the power domain of NOMA. The potential gains of NOMA over OMA (orthogonal multiple access) are discussed to show that NOMA is better than OMA. Figure 27: OFDMA in BackCom. (**a**) Block diagram of the transceiver model for wireless power and information transfer; (**b**) OFDMA downlink communication system with various mobile receivers. **Discussion:** Table 8 summarizes the multiple access techniques for BackCom. Moreover, various multiple access techniques for BackCom are suggested to accommodate multiple tags at the same time. These techniques are highlighted below:  
1. Multiple access techniques, including TDMA [101], CDMA [103], OFDMA [104], and NOMA [105, 106], are proposed for BackCom. 2. All schemes accommodate the maximum number of users at the same time. 3. We can observe from the above literature that NOMA has a better performance than all others; therefore, NOMA is widely supported by 5G [105]. 4. NOMA has the potential to meet future demands of connecting a large number of IoT devices. Let us now consider power sources for BackCom. Adequate data and power transfer methods, in addition to scheduling and resource allocations for BackCom, are also elaborated.
## 4 Simulation Results and Analysis
### Analysis of a Central Point  
Figure 11 offers a zoomed-in view of a single test point at the center of our grid (1.0 m, 1.0 m), allowing for a detailed examination. The distribution of estimates (red dots) forms a line around the actual position, indicating balanced errors in the x- and y-directions at this central location. The tight clustering of estimates suggests high precision, with most estimates falling within a small area. The proximity of the estimated cluster to the actual position (red cross) demonstrates high accuracy with no significant systematic bias. The relatively small size of the error circles, particularly the average error circle (green dotted), indicates good overall accuracy at this central point. This central point's equidistant position from all beacons likely contributes to its high accuracy, showcasing the optimal performance of the system under ideal conditions.
# Performance Evaluation of IM/DD FSO Communication System Under Dust Storm Conditions
## 3 System Model and Performance Analysis  
We consider an FSO communication system employing intensity modulation with direct detection (IM/DD) and On-Off Keying (OOK) modulation. The received electrical signal is modeled as follows:  
\[y=Rlx+n, \tag{6}\]  
where \(y\) denotes the output current of the photodetector (in amperes), \(R\) is the photodetector responsivity (A/W), and \(x\in\{0,2P_{t}\}\) represents the transmitted symbols under OOK modulation conditions with average optical power \(P_{t}\). The term \(I\) denotes the normalized irradiance, representing the atmospheric fading effect due to dust, and \(n\) is additive white Gaussian noise (AWGN) modeled as a zero-mean Gaussian random variable with variance \(\sigma_{n}^{2}\). Unlike prior studies that model composite effects such as fog, turbulence, and pointing errors, this work focuses on isolating and rigorously investigating the impact of dust-induced fading under probabilistic modeling conditions. This choice is motivated by the lack of dedicated studies in this domain and the need to understand dust's standalone influence before considering compound impairment. The model thus serves as a foundational step toward a broader multi-impairment analysis.  
The instantaneous electrical signal-to-noise ratio (SNR) at the receiver, conditioned on a realization of the channel gain \(h\), is given by [15]  
\[\gamma(h)=\frac{2P_{t}^{2}R^{2}l^{2}}{\sigma_{n}^{2}}=\eta l^{2}, \tag{7}\]  
where the system-dependent SNR scaling factor is defined as  
\[\eta\triangleq\frac{2P_{t}^{2}R^{2}}{\sigma_{n}^{2}}. \tag{8}\]
## 2 Lignin
### Properties and Applications of Lignosulfonates  
Lignosulfonate has strong dispersibility, cohesion, and chelation. The abundant phenolic hydroxyl groups endow lignin with excellent antioxidant, antibacterial and UV protection properties [26], these active sites are beneficial for the preparation of composite materials [27; 28; 29]; Polar functional groups such as hydroxyl and carboxyl can weaken the surface force when compounding with other materials [22; 30; 31; 32]; sulfonic acid groups have good water solubility. The natural degradation process of lignin is very slow. At present, only white-rot fungi have been found to completely degrade lignin; therefore, the durability of lignocellulosic can be guaranteed after being incorporated into loess [33; 34].  
Because of their surface activity, lignocellulosiconates are often used in other fields, such as dyes, the coal industry, and the construction industry, such as in clay pavement reinforcement [35] and as a concrete water reducing agent [36; 37], adsorbent [38], dispersant [39; 40; 41], catalyst [42], etc. In recent years, research on improving loess with lignocellulosiconates has gradually increased. In 2017, [PERSON] et al. [43] found that when the amount of lignocellulosiconates was too large, agglomeration occurs, which affects the soil improvement effect. This phenomenon is directly related to the molecular weight of lignocellulosiconate [44], and the relative molecular weight of lignocellulosic is larger than other types of lignin [45]; therefore, there is the problem of optimal dosage of lignocellulosic to improve loess in theory.  
Figure 1: Structural representation of lignin with cellulose in a plant cell, reproduced with permission from [21].  
Figure 2: Three types of C\({}_{6}\)C\({}_{3}\) monomer units in lignin [25]. (**a**) p-Hydrooxyphenyl unit(H); (**b**) Guaiacyl unit (G); (**c**) Syringyl unit (S).
## 3 Circuit Implementation  
As shown in Figure 1, the proposed power amplifier (PA) is composed of a power control circuit, two-stage power cells, on-chip matching circuits(including on-chip transformers and capacitors),and integrated bias circuits. The power cells utilize a differential structure to compensate for even-order harmonics and common-mode fluctuations caused by ground bonding wires.
## 4 Proposed Data Collection Algorithms
### Grid and Probabilistic Neighborhood-Based Data Collection Algorithm with Layered-Scan(GPN-LSCAN)
#### 4.1.1 Network Partition Phase  
First, according to the equations discussed in Section 3, the control center computes the probabilistic neighborhood range \(d\_p\) of the required parameter \(p\). In order to ensure that all the nodes in one grid can send their storage data to the AUV, the grid must be fully included in the probabilistic neighborhood contour. As shown in Figure 2, the maximal unit cube is an inscribed regular hexahedron of the probabilistic neighborhood contour sphere. Clearly the final grid side length \(l\) can be calculated by:  
\[l_{max}=\frac{2\sqrt{3}d\_p}{3} \tag{12}\]  
\[k=\lceil\frac{L}{l_{max}}\rceil=\lceil\frac{\sqrt{3}L}{2d\_p}\rceil \tag{13}\]  
\[l=\frac{L}{k}=\frac{L}{\lceil\sqrt{3}L/2d\_p}\rceil \tag{14}\]  
where \(l_{max}\) is the side length of inscribed regular hexahedron, and \(L\) is the side length of network. Then, the 3D UASN is divided into \(k*k*k\) cubes with the side length of \(l\) as shown in Figure 3.  
Figure 2: Grid size calculation in GPN-LSCAN.
## 2 The application of Additive Manufacturing (AM) in industry 4.0
### Hybrid Additive Manufacturing in Micro/Nano-Scale  
The process of micro/nano-scale additive manufacturing is considered as the next generation of the AM processes and is highly under investigation for new opportunities and solutions to the new problems. Having parts in the micro/nano-scale requires precision machines that are accurately controlled by computers [10]. However, based on the literature, as yet, the best results are achieved out of hybrid manufacturing processes that are a combination of additive and subtractive processes [83]. These processes can take place either concurrently or in sequence to complete the required task from the machines and there is no limitation on the number of processes utilized in order to produce the 3D object. The goal of hybrid manufacturing is to get the input materials and change them to the final product in one machine or workstation [84]. On the same page, the goal of the hybrid manufacturing processes is to utilize AM processes as the primary step of the manufacturing and use the benefits of the other assistive processes to get the highest accuracy [85]. The idea of hybridization of AM machines with the other processes is that in most of the AM-fabricated parts, there is still a need for mechanical polishing. On the other hand, all these processes are computer-controlled and they can be easily integrated as a unit which satisfies the goal of Industry 4.0 [10]. As an example, an AM machine makes the core of a sphere and after that, a machining process reduces the burrs and increases the geometrical accuracy of the sphere. Figure 5 represents a schematic flowchart of a hybrid AM-machining process, which can be used in micro/nano-scale applications. In this process, the input material is fed into the system and a fully computer-controlled system and based on the feedback, it will go to the finished parts or it will go back to different stages of the manufacturing process. After the point that the part has met all the required criteria, it will pass the manufacturing stage and gets prepared for other steps prior to being delivered to the customers [85; 86; 87; 88]. Figure 6 represents a future example of how hybrid manufacturing can be conducted in micro/nano-scale in order to have a final product in one machine or one workstation regardless of the steps which take place in order to complete the parts [82]. As it is shown, different computer-controlled processes are integrated into one station. In the first position, the support structures are deposited, and some machining processes will make the desired mold shape for polymer injection. At the second station, laser machining makes the ideal shape for part placement while a circuit maker provides the electronic connections embedded into the internal features of the component [89]. In the last station, the finalization processes take place to make the product that is, in fact, a complete product ready to work.  
Figure 5: A closed loop of hybrid manufacturing for micro/nano-scale additive manufacturing [85].
## 3 Calculation of Propagation Time and Attenuation Rate Using the Amiet Method
### Effect of the Refraction on the Propagation Path  
Figure 2d shows a schematic image of the acoustic propagation in the \(X_{n}^{\prime}-Y_{n}^{\prime}\) plane. When the flow velocity in the wind tunnel is zero, acoustic waves travel along the dashed line with the propagation angle of \(\theta^{\prime}\). However, there is actually a flow in the wind tunnel and the sound wave propagation path changes, as shown by the red solid line at the propagation angle \(\theta\).  
The geometric relationship can be derived, as shown in Figure 2d,  
\[R_{m}\cos\theta_{m}=R_{t}\cot\theta+(R_{m}\sin\theta_{m}-R_{t})\cot\theta_{0} \tag{1}\]  
where \(R_{m}\), \(R_{t}\), \(\theta_{m}\), and \(\theta_{0}\) are the distance from the sound source to the microphone, the distance between the sound source to the shear layer, the angle to source-microphone vector, and the angle to shear layer-microphone vector, respectively.  
The relationship between \(\theta\) and \(\theta^{\prime}\) can be obtained from the convection of the acoustic wave,  
\[\tan\theta=\frac{\sin\theta^{\prime}}{\cos\theta^{\prime}-M^{\prime}}, \tag{2}\]  
where \(M\) is the Mach number of the flow.  
[PERSON]'s law gives the relationship, as follows:  
\[M=\frac{1}{\cos\theta^{\prime}}-\frac{1}{\cos\theta_{0}}, \tag{3}\]  
where \(R_{m}\), \(R_{t}\), \(\theta_{m}\), and \(M\) are the known values. Equations (1) to (3) are iteratively solved, and \(\theta\), \(\theta_{0}\), and \(\theta^{\prime}\) are obtained.
# Performance Optimization of Grounding System for Multi-Voltage Electrical Installation
## 5 Comparative Analysis of Grounding Performance
### 400 V System (Low-Voltage) Grounding  
In a commercial facility operating a 400 V three-phase system, a phase-to-ground fault occurs due to cable insulation failure, resulting in a fault current of 5 kA. The grounding system consists of a 2 m deep copper rod, and the surrounding soil has a resistivity of 100 \(\Omega\cdot\)m. The resistance of the grounding system can be calculated using Equation (14),  
Substituting the given values, \(\rho=100\)\(\Omega\cdot\)m, \(L=2\) m, \(d=16\) mm into Equation (14),  
\[=\frac{100}{2\pi\times 2}\ln\left(\frac{4\times 2}{0.016}\right)=3.2\ \Omega\]  
The fault current dissipation can be determined by multiplying the fault current (5 kA) by the calculated resistance (3.2 \(\Omega\))  
\[V_{GPR}=I_{f}R \tag{20}\]  
From Equation (20),  
\[V_{GPR}=5000\,\text{A}\times 3.2\ \Omega=16,\!000\ \text{V}\]  
The resulting ground potential rise (GPR) of 16,000 V exceeds safe limits, posing a potential safety hazard. Therefore, to mitigate the risk, additional grounding rods are required to effectively reduce the GPR and ensure the safety of the system. To mitigate high ground potential rise (GPR), multiple grounding rods can be deployed in parallel, significantly reducing the overall resistance and enhancing fault current dissipation [21]. When \(n\) identical grounding rods are installed in parallel, the equivalent resistance \(R_{new}\) is given by the following:  
\[R_{new}=\frac{R}{n} \tag{21}\]  
Table 7 shows the typical configurations and cost-effective solutions for a 400 V grounding system.  
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Parameter** & **400 V System (LV)** & **10 kV System (MV)** & **35 kV System (HV)** \\ \hline Application & Residential, commercial, small-scale industries & Industrial distribution, substations, EV charging & Transmission substations, large-scale power distribution \\ \hline Fault Current (kA) & 2–10 & 10–25 & 15–40 \\ \hline Grounding Electrode & Single rod or grid & Deep-driven rods and grid & Extensive grounding grid + counterpoise \\ \hline Resistance (\(R\)) & 1–5 \(\Omega\) & 0.5–3 \(\Omega\) & \textless{1} \(\Omega\) \\ \hline Ground Potential Rise (GPR) (V) & 200–2000 & 2000–5000 & 5000–10,000 \\ \hline Step Voltage (V) & \textless{}500 & 1000–2000 & 2000–4000 \\ \hline Touch Voltage (V) & \textless{}250 & 500–1500 & 1500–3000 \\ \hline Mitigation Measures & Rod extension, equipotential bonding & Additional rods, bentonite, grounding mesh & Large grounding grids, counterpoise, deep wells \\ \hline \hline \end{tabular}
\end{table}
Table 6: Comparison of grounding system configurations.
## 3 Doppler OCT for Otology Applications
### Ex Vivo Studies
#### 3.2.1 Small Animal Studies  
[PERSON] et al. [67] initially measured the cochlea of small animal (Mongolian gerbil) ex vivo using Doppler optical coherence microscopy (OCM). In addition to the obtained anatomical structure of the middle ear using OCT, the functional vibrating motion of the middle ear is captured by applying the Doppler technique. This experiment presented the ability of Doppler OCM to discriminate the motion of the cochlea structure (basilar membrane, vectorial membrane, reticular lamina, and outer hair cells).  
In addition to the measured two-dimensional (2D) cross-sectional motion data of cochlea in [67], [PERSON] et al. [68] measured the three-dimensional (3D) vibrating pattern of the TM and ossicles of the chinchilla ear using OCV with sub-nanometer scale sensitivity. By measuring the volumetric vibrating information of the manubrium, the distinctive characteristic of each region was obtained. This study revealed the different simulated pathologies derived from the simultaneously measured ossicular motion information with the movement of the TM.  
As an aspect of the sensitivity of the Doppler OCT system, [PERSON] et al. [69] demonstrated phase-sensitive OCT with a Vernier-tuned distributed Bragg reflector swept laser and measured the vibrations of the mouse middle ear to validate the sensitivity enhancement. Since sensitivity is one of the crucial factors of Doppler OCT performance, multiple attempts have been made to study and improve the sensitivity. Unlike conventional algorithm-based research to enhance the performance, [PERSON] et al. [69] utilized a swept laser, which provides a highly linear sweeping rate with high stability and repeatability. Based on these advantages of the Vernier-tuned distributed Bragg reflector swept laser, a simplified systematic design was used and demonstrated the near shot-noise-limited phase sensitivity.  
To overcome the frequency limit of applied sound and random phase noise drift, [PERSON] et al. [47] developed an OCT system for the precise measurement of the phase delay. With this system, both the sound-induced vibrating motion of the TM and ossicles of the chinchilla ear can be simultaneously measured and visualized. As shown in Figure 3, different characteristics of the prominent structures (i.e., manubrium of the malleus, incus, and stapes) were measured according to the applied frequencies (0.5, 6.4, and 15.0 kHz). This study revealed an undescribed vibration mode of chinchilla ossicles measured at high frequencies.
## 3 Results and Discussion
### In Vitro Skin Permeation Studies with ETB-NEG  
Comparative studies are widely reported for establishing the efficiency of NEG formulations over conventional ETB gel formulations [22; 38]. Therefore, it was imperative in the present study to show that the developed ETB-NEG was superior to ETB gel in terms of in vitro permeation. The in vitro skin permeation study evaluated the permeation of ETB through rat skin when presented as ETB-NEG in comparison to ETB gel formulation. The permeation was evaluated in terms of flux, P\({}_{\text{app}}\), and enhancement ratio [40; 41]. The flux of ETB was found to be 0.72 \(\pm\) 0.03 and 0.47 \(\pm\)0.04 \(\mu\)g cm\({}^{-2}\) h\({}^{-1}\) for ETB-NEG and ETB gel, respectively. Thus, the ETB flux from ETB-NEG was significantly higher (\(p\) < 0.05) than that from ETB gel. This highlighted the importance of the developed ETB-NEG formulation. In consensus with the flux, the P\({}_{\text{app}}\) value was higher for ETB-NEG compared to ETB gel. The P\({}_{\text{app}}\) value was 0.072 cm\({}^{-2}\) h\({}^{-1}\) for ETB-NEG, while it was only 0.047 cm\({}^{-2}\) h\({}^{-1}\) for ETB gel. Thus, the enhancement ratio of 1.53 was obtained for ETB-NEG. Overall, the permeation studies confirmed the effectiveness of the ETB-NEG formulation over the ETB gel in the ability to deliver the drug across the skin.