esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Application in Determination of Rock-Mass Properties
### Poisson's Ratio Value  
Compared to the other basic mechanical properties of the rock mass, Poisson's ratio is an elastic constant whose importance is generally underrated [110]. The behavior of rock masses is influenced by the mechanical behavior and properties of discontinuities and of the intact rock bounded by discontinuities. The _UCS_ test on a rock mass (\(\sigma_{cm}\)) indicated that \(\
u_{m}\) has an inverse relation with the \(\sigma_{cm}\)[111], as expressed in Equation (42). As \(RMR\) and \(Q\) systems are used for calculation of \(\sigma_{cm}\), these systems can be used indirectly for the calculation of \(\
u_{m}\).  
\[\
u_{m}=0.25\Big{(}1+e^{-0.2\sigma_{cm}}\Big{)} \tag{42}\]  
A direct method of determining \(\
u_{m}\) from the \(RMR\) value was proposed [93; 112] and is expressed in Equation (43).  
\[\
u_{m}=0.5-0.2\frac{RMR_{89}}{RMR_{89}+0.2(100-RMR_{89})} \tag{43}\]  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**S. No.** & **Equation** & **Equation No.** & **Reference** \\ \hline
1 & \(\frac{\sigma_{cm}}{\sigma_{c}}=\sqrt{e^{\frac{RMR_{89}-100}{9}}}\) & (36) & [99] \\
3 & \(\frac{\sigma_{cm}}{\sigma_{c}}=e^{\frac{RMR_{89}-100}{185}}\) & (37) & [106] \\
4 & \(\frac{\sigma_{cm}}{\sigma_{c}}=\frac{e^{\frac{RMR_{89}-100}{20}}}{100}\) & (38) & [67] \\
5 & \(\frac{\sigma_{cm}}{\sigma_{c}}=\frac{7}{100}\,\Omega^{1/3}\), \(\gamma\) in t/m\({}^{3}\) & (39) & [107] \\
6 & \(\frac{\sigma_{cm}}{\sigma_{c}}=e^{\frac{\sigma_{cm}}{30}-100}\) & (40) & [108] \\
7 & \(\frac{\sigma_{cm}}{\sigma_{c}}=\frac{RMR_{89}}{RMR_{89}+6(100-RMR_{89})}\) & (41) & [109] \\ \hline \hline \end{tabular}
\end{table}
Table 6: Equations for calculation of \(\sigma_{cm}\) without \(\sigma_{c}\).  
This equation was modified and according to this modification, the ratio of \(\
u_{m}\) and \(\
u_{i}\) is a function of the corresponding _RMR_ value [93], as shown in Equation (44).  
\[\frac{\
u_{m}}{\
u_{i}}=2.5-1.5\times\frac{RMR_{89}}{RMR_{89}+(100-RMR_{89})} \tag{44}\]
## 1 Efficient Sparse Signal Transmission over a Lossy Link Using Compressive Sensing  
**[PERSON] 1, [PERSON] 1, [PERSON] 1, [PERSON] 2 and [PERSON] 1,* * 1 State Key Laboratory of Industrial Control Technology, Zhejiang University, Zheda Road 38 th, Hangzhou 310027, China; E-Mails: [EMAIL_ADDRESS] (L.W.); [EMAIL_ADDRESS] (K.Y.); [EMAIL_ADDRESS] (D.C.) 2 Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; E-Mail: [EMAIL_ADDRESS]**  
* Author to whom correspondence should be addressed; E-Mail: [EMAIL_ADDRESS]; Tel.: +86-186-5810-0255.  
Academic Editor: [PERSON]  
_Received: 27 June 2015 / Accepted: 31 July 2015 / Published: 13 August 2015_  
**Abstract:** Reliable data transmission over lossy communication link is expensive due to overheads for error protection. For signals that have inherent sparse structures, compressive sensing (CS) is applied to facilitate efficient sparse signal transmissions over lossy communication links without data compression or error protection. The natural packet loss in the lossy link is modeled as a random sampling process of the transmitted data, and the original signal will be reconstructed from the lossy transmission results using the CS-based reconstruction method at the receiving end. The impacts of packet lengths on transmission efficiency under different channel conditions have been discussed, and interleaving is incorporated to mitigate the impact of burst data loss. Extensive simulations and experiments have been conducted and compared to the traditional automatic repeat request (ARQ) interpolation technique, and very favorable results have been observed in terms of both accuracy of the reconstructed signals and the transmission energy consumption. Furthermore, the packet length effect provides useful insights for using compressed sensing for efficient sparse signal transmission via lossy links.  
**Keywords:** lossy wireless link; compressive sensing; sparse signal transmission; packet length control
## 2 Materials and Methods
### Photocatalytic Test  
A stock solution of 1000 ppm was prepared from Levafix Dark Blue, and a further dilution was carried out when needed to obtain 50, 100, 150, and 200 ppm. Initially, 100 mL of the 100 ppm of Levafix Dark Blue dye-containing aqueous solution was poured into a glass container to subject it to the photocatalytic test. Then, a certain amount of [PERSON]'s earth augmented with hydrogen peroxide (30% \(w/v\)) supplied by Sigma-Aldrich (Burlington, MA, USA) was poured into a container as the source of the Fenton photocatalyst and placed in a photochemical reactor. The mixture was magnetically stirred and kept under UV illumination after the pH was adjusted, if desired (using AD1030, Adwa instrument, Szeged, Hungary), over the range of 3.0 to 8.0. The pH of the dye aqueous solution was adjusted to the desired values by using diluted H\({}_{2}\)SO\({}_{4}\) (1:9) and/or 1M NaOH solutions (Sigma-Aldrich). All chemicals were used as received from the supplier without further treatment or purification.  
In order to validate the effect of the Levafix Dark Blue dye concentration on the extent of photocatalytic oxidation, the polluted water with the reagents was subjected to the photocatalytic system. A UV lamp (15 W, 230 V/50 Hz, with a 253.7 nm wavelength) was used to emit UV light during the reaction. The lamp was covered with a silica tube jacket for lamp protection, still allowing the UV to penetrate the dye-containing solution. The sleeved UV lamp was located inside a glass vessel containing the wastewater solution to well induce and accelerate the photocatalytic reaction. The photo-reactor had a 250 mL volume, and the reactor was fully exposed to UV light.  
In regular time intervals (every 10 min), the samples were subjected to analysis after filtration (0.45 \(\upmu\)m) to remove the remaining excess catalyst using a UV-visible spectrophotometer (Unico UV-2100, Franksville, WI, USA). The results of the analysis were recorded, and the data are presented as the dye percentage removal. The experimental setup is summarized in Figure 1.  
Figure 1: Schematic representation of the catalyst preparation and treatment steps.
## 6 Conclusions  
This study examined the use of multiple variables (vegetation growth, surface moisture, radiative energy, and other relative variables) as inputs for various regression algorithms, including Multiple Linear Regression (MLR), Random Forest Regression (RFR), and Backpropagation Neural Network (BPNN), to estimate water (ET) and carbon fluxes (NEE). The key findings can be summarized as follows:  
1. Increasing the number of input variables typically improved the accuracy of ET and NEE estimations. Here, four types of variables used together (RFR) resulted in the best accuracy for ET (R\({}^{2}\) of 0.81 and an RMSE of 1.13 mm) and NEE (R\({}^{2}\) of 0.83 and an RMSE of 2.83 gC/m\({}^{2}\)) estimations. Moreover, vegetation growth variables (i.e., VIs) are the most important inputs for ET and NEE estimation;
2. Among the three regression algorithms tested, each demonstrated different levels of accuracy in estimating ET and NEE. Overall, RFR proved to be the most accurate for both ET and NEE estimations;
3. The proposed ET and NEE estimation models exhibited some variation in accuracy across different validation sites. Specifically, the R\({}^{2}\) for ET estimation ranged from 0.51 to 0.87, and the RMSE fluctuated between 0.94 and 2.28 mm across the six sites. Similarly, for NEE estimation, the R\({}^{2}\) spanned from 0.35 to 0.80, with the RMSE varying from 1.42 to 5.48 gC/m\({}^{2}\). Despite these variations, the accuracy levels across all six validation sites remained relatively high.  
The findings presented in this study demonstrate the potential of using Landsat observations in combination with machine learning techniques to simultaneously estimate ET and NEE. This approach lays the groundwork for an efficient method in agricultural water resource and ecosystem monitoring and management.  
Methodology, M.C.; Resources, Z.L. and C.S.; Writing--original draft, M.C.; Writing--review & editing, J.X., K.L. and C.S.; Visualization, Z.Z. All authors have read and agreed to the published version of the manuscript.  
This research was supported by National Natural Science Foundation of China (Grant No. 42301366), China Postdoctoral Science Foundation (Grant No. 2023M733001), Basic Research Program Natural Science Foundation of Jiangsu Province (Grant No. SBK2023043261) and A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).  
No new data were created or analyzed in this study. Data sharing is not applicable to this article.  
The authors declare no conflict of interest.
# A Review of the Synthesis and Applications of Polymer-Nanoclay Composites
## 2 Synthesis
### Melt-Blending Method
The tensile strength of the composites (5% expanded organoclay) showed a good correlation with the properties of the water vapor permeability barrier, making them a promising candidate for food packaging and biomedical applications. [PERSON] et al. [87] improved the electrical conductivity of the membranes made of styrene-co-acrylonitrile (SAN) reinforced with carbon nanotubes (CNTs) using a one-step reactive melt blending method. The results showed that simple reactive melt blending may improve the tensile stress and dynamic modulus of SAN membranes and the dispersion of CNTs in SAN matrix. [PERSON] et al. [88] compared the effects of melt blending and solution blending methods on the physical properties of thermoplastic polyurethane/nanoclay composite films; nanoclays exhibited a higher dispersion, exfoliated, and semi-exfoliated structures in the melting blending synthesized samples compared to those from the solution blending experiments. The melt blending method appeared to result in improvements in creep resistance, and the gas and water vapor permeability of polyurethane/nanoclay films. [PERSON] et al. [89] applied a novel melting blending method using supercritical carbon dioxide (scCO\({}_{2}\)) as a processing aid to exfoliate nanoclays and improved its dispersion after melt blending in nylon 6 matrices. The synthesized nylon 6/nanoclay composites exhibited improved mechanical properties due to favorable interactions between the clay and polymers. [PERSON] et al. [90] modified isotactic polypropylene (iPP) fibers via melt blending in a twin-screw extruder. The preparation process increased the interaction between nano-capsules, the hydrophobic PP matrix and the dispersion of nano-capsules. The study concluded that the incorporated nanoclays showedlittle influence on the crystallization behavior and thermal stability of iPP. [PERSON] et al. [91] applied melt blending to synthesize highly hemocompatible and biocompatible polymer/nanoclay composites using different molecular weights of poly(methyl methacrylate) (PMMA) and different concentrations of nanohydroxapatite (nHAp). This study investigated the effects of the molecular weight of PMMA on hemocompatibility, cytotoxicity, and genotoxicity of composites, and the polymer/nanoclay composites appeared to have potential uses in clinical applications, particularly in dentistry. The dispersion of nanoclay in rubber polymers is challenging due to its amorphous nature, high viscosity, and low surface energy compared with thermoplastic polymers [2]. Thus, high temperature melt blending with extrusion may be a promising technique [92].
# Interval Extended Kalman Filter--Application to Underwater Localization and Control
## 3 Filters
### Interval Extended Kalman Filter  
Since the EKF can diverge if the linearization point is far from the real state, we propose a new observer called IEKF (Interval EKF). This filter consists of an interval filter and an extended Kalman filter. The interval filter helps the second filter by taking as a linearization point \(\bar{\mathbf{x}}_{k}\), a point inside the list of boxes \(L_{x,k}\). This point can be, for instance, the center of one of the boxes in \(L_{x,k}\), which maximizes the consistency with respect to the observations. Now, \(\bar{\mathbf{x}}_{k}\) may also be the estimate given by the IEKF when the latter is consistent enough.  
Here, the IEKF corresponds to a classical EKF helped by an IF: it uses a consistency approach to select the linearization point. As a result, it will behave as a classical EKF as soon as we are close to the true solution, and the trajectory will be smooth and precise as shown in the following section. Now, when the estimated trajectory is far from the true solution, the IEKF will benefit from the global view provided by set-membership approach. The resulting observer will inherit both from the accuracy of EKF near to the solution and also to the high level of integrity provided by the IF.
## 7 New Challenge: Multimodality
### Dependence on Satellite Positioning System  
AVs often rely on Global Navigation Satellite Systems (GNSSs) like GPS for precise positioning [81]. However, this introduces several safety concerns:  
* Signal Interference and Spoofing: GNSS signals can be disrupted by natural phenomena (e.g., solar flares) or \"urban canyons\" (tall buildings blocking signals). Worse, malicious actors can spoof signals [82], feeding false location data to a vehicle, potentially causing it to misjudge its position and crash.
* Latency: Even slight delays in satellite data transmission can be problematic for a vehicle moving at high speed, where split-second decisions are critical. Furthermore, Satellite Navigation Systems are not always conceived with the aim of being used for safety critical applications.
* Loss of Signal: In tunnels, dense forests, or remote areas, signal loss can leave a vehicle \"blind\", forcing it to rely solely on onboard sensors.
###### Abstract  
The main aim of the present paper is to solve numerically the free vibration problem of sandwich shell structures with variable thickness and made of Functionally Graded Materials (FGMs). Several Higher-order Shear Deformation Theories (HSDTs), defined by a unified formulation, are employed in the study. The FGM structures are characterized by variable mechanical properties due to the through-the-thickness variation of the volume fraction distribution of the two constituents and the arbitrary thickness profile. A four-parameter power law expression is introduced to describe the FGMs, whereas general relations are used to define the thickness variation, which can affect both the principal coordinates of the shell reference domain. A local scheme of the Generalized Differential Quadrature (GDQ) method is employed as numerical tool. The natural frequencies are obtained varying the exponent of the volume fraction distributions using higher-order theories based on a unified formulation. The structural models considered are two-dimensional and require less degrees of freedom when compared to the corresponding three-dimensional finite element (FE) models, which require a huge number of elements to describe the same geometries accurately. A comparison of the present results with the FE solutions is carried out for the isotropic cases only, whereas the numerical results available in the literature are used to prove the validity as well as accuracy of the current approach in dealing with FGM structures characterized by a variable thickness profile.  
keywords: functionally graded materials; free vibration analysis; local generalized differential quadrature method; higher-order structural theories; variable thickness shells +
Footnote †: journal: Applied Mechanics and Physics Letters
# Algoritlms
## 2 Materials and Methods
### Managing Bias in the Narrative Review  
To ensure the narrative review was objective and rigorous, several strategies were employed to manage and minimize bias throughout the assessment process. Here's how biases were managed:  
_Diverse Assessors:_Each study was reviewed by two primary assessors [DG] and [AL] with different backgrounds. The inclusion of assessors from different backgrounds and expertise levels was intended to capture a range of perspectives and reduce the likelihood of individual biases influencing the evaluation process.  
_Clear Assessment Criteria:_  
The assessment was based on defined parameters: Clarity of Rationale, Design Appropriateness, Methodological Clarity, Result Presentation, Justification of Conclusions, and Disclosure of Conflicts of Interest. Furthermore, data were presented based on a standardized checklist. By using predefined parameters, the review process reduced the risk of subjective interpretation.  
_Scoring System:_  
Each parameter was scored on a scale from 1 to 5, with a binary assessment for the disclosure of conflicts of interest (Yes/No). This quantifiable approach allowed for consistent evaluation across studies and provided a transparent mechanism for comparing study quality.  
_Independent Review:_  
The primary assessors independently reviewed the studies and assigned scores without consulting each other initially. This independence helped to ensure that individual judgments were based solely on the studies' merit and the predefined criteria, minimizing the influence of groupthink or shared biases.  
_Dispute Resolution:_  
In cases where the two primary assessors disagreed on scores or the inclusion of a study, a third assessor, either [AP] or [GL] (with different backgrounds), was involved to resolve the dispute. This third-party adjudication aimed to provide an impartial perspective and resolve conflicts fairly. The involvement of a third assessor added an extra layer of scrutiny and balance to the review process.  
_Structured Mechanism for Disagreements:_  
The process for resolving disagreements was structured and formalized. The third assessor reviewed the initial evaluations and provided a reasoned judgment to reconcile differences. This structured approach ensured that conflicts were addressed systematically and that final decisions were based on a comprehensive evaluation.  
_Transparency:_  
The use of a standardized checklist for presenting data and a clear scoring system provided transparency in the assessment process. By documenting the criteria and the scoring rationale, the review process was made transparent, allowing for a clear understanding of how decisions were made and reducing the potential for undisclosed biases.  
By incorporating these strategies, this review aimed to offer a thorough and balanced evaluation of the literature. The multi-assessor approach, coupled with structured criteria and formal dispute resolution, was designed to minimize bias and enhance the reliability and objectivity of the review process.
# An Optically Transparent Metasurface for Microwave Amplitude-Phase Manipulation
###### Abstract
Moreover, ITO films suffer from other limitations such as brittleness, insufficient chemical and thermal stability, high cost, and the scarcity of indium resources, which hinder their widespread application in sophisticated devices requiring stability and flexibility. Another effective method used to further improve optical transparency is the use of ultra-thin metallic meshes. By leveraging meta-atom designs or judiciously tailoring the geometries of conductive meshes, such metasurfaces can manipulate microwave properties, including transmission [23; 24; 25], absorption [26], and polarization conversion [27], without obstructing visible transparency. Unfortunately, the lithography process for fabricating metallic meshes is undoubtedly time-consuming and high-cost, which is not desirable for metasurface industrialization. Thus, designing and manufacturing an optically transparent microwave metasurface in a low-cost and reliable way remains a big challenge. In this work, we have presented an approach, simple in concept and in practice, that uses a metal frame to construct an optically transparent meta-atom possessing independent and complete manipulation of the microwave amplitude and phase profiles. To achieve optical transparency, metallic patterns were replaced by an elaborately designed metal frame with a low filling ratio, while the traditional metal backplane of reflection-type metasurfaces was replaced by metallic meshes. Both the metal-frame-based resonator and bottom mesh layer can be easily attained by means of flexible printed circuit (FPC) technology, which is mature and low-cost. Regarding the microwave region, the amplitude was continuously controlled from 0 to 0.9 by in-plane rotation, whereas eight-level phase modulation with an interval of \(\pi/4\) was realized by changing the geometric size and orientation angle of the H-shaped resonator. It should be noted that the manipulation of amplitude and phase is independent and has low crosstalk, facilitating the implementation of high-quality wavefront control. To demonstrate the advantages of the proposed transparent meta-atom, we designed and experimentally validated a spatially multiplexed complex-amplitude hologram, as shown in Figure 1a. Two holographic images of \"WH\" and \"UT\" were separately reconstructed on the different predetermined imaging planes at 16 GHz. The experimental results agree with the theoretical predictions and numerical simulations, validating the capability of the proposed meta-atom for amplitude-phase manipulation. More importantly, in contrast to previous studies [28; 29; 30; 31], the low filling ratio of metal-frame-based resonators and metallic meshes facilitated the high visible transparency (\(-63.7\%\)) of the entire metasurface.
# Secure and Time-Aware Communication of Wireless Sensors Monitoring Overhead Transmission Lines
## 5 Results Analysis and Discussion
The time difference between first scenarios for different distances  
Figure 10. Scenarios 5a,b: correlation between the sink number, time and power grid disturbance time frames (encryption/no encryption). Figure 9. Scenarios 3a,b, 4a,b: correlation between the sink number, time and power grid disturbance time frames (encryption/no encryption). and node 1 is equal to about one tenth of a second. (The same is true for Scenarios 2-5). Node 22, located in the middle of the transmission line, is as well characterized by negligible differences in transmission time when considering different distances. For node 22, only Scenarios 1 and 5 have slightly larger changes in transmission time when comparing the delays on given distances. Identical situation applies to sensor 45. The time difference between different distances exists in every scenario. However, it is so small, that it is almost imperceptible.