esa-sceva/satcom-chunk-collection huggingface dataset:
## 1 Introduction
[20] carried out a series of large-scale direct shear tests on dense sand concrete interface under constant and varying normal stresses using a large-scale direct shear apparatus, analyzed the shear stress and volume strain characteristics of dense sand concrete and established the mathematical model of dense sand concrete interface. [PERSON] et al. [21] carried out a series of shear tests on the loose sand concrete interface constant/varying normal stress using the SHARE Trace-III large-scale direct shear apparatus. The shear stress and volume strain characteristics of the interface between loose sand and concrete were analyzed, and a mathematical model reflecting the shear mechanical properties of the interface between loose sand and concrete was established. [PERSON] et al. [22] studied and evaluated the shear resistance of Misurata wet sand around the foundation surface under different axial loads through direct shear box tests. [PERSON] et al. [23] studied the long-term performance of the structure on the soft clay foundation after the saturated clay was subjected to the seismic cyclic shear. [PERSON] et al. [24] conducted undrained triaxial tests on remolded and undisturbed London clay and stress detection tests on undisturbed London clay. [PERSON] [25] developed a test procedure to determine the shear strength and deformation of cement soil samples with different cement content and age under a triaxial load. [PERSON]. [PERSON] et al. [26] proposed a more advanced model, cyclic kinematic deviatoric loading, based on the Modified Cam-Clay, which is especially useful for modelling concrete materialsat different loading conditions. The abovementioned research provides a good reference for the experimental study of the shear mechanical characteristics of the sand concrete interface under variable normal stress and the uniaxial and triaxial tests of clay and cement soil. Because there are few reports on the experimental research on the shear mechanical properties of different soils, especially the interface between cement soil and concrete under variable normal stress, based on the self-developed large-scale interface shear equipment, this paper carried out the interface shear tests under two modes: the repeated loading and unloading of normal stress and the multi-stage continuous loading of normal stress. In addition, this paper analyzed the shear properties of different soils, especially the interface between cement soil and concrete under variable normal stress. The theoretical formula of the minimum friction coefficient of the interface was derived, and the interaction mechanism of the interface under the two loading models was further revealed. The research results can provide a reference for the determination of the friction coefficient of cement soil concrete interface in the foundation engineering of suspension bridge anchorage foundations and offshore wind power gravity foundations.
## 3 Results and Discussion
### X-ray Diffraction Analysis  
Additionally, structural characterization of the sample is essential to support the configuration of the obtained nanoparticles. Figure 3 displays the X-ray diffraction (XRD) analysis of the Fe\({}_{3}\)O\({}_{4}\)-Ag sample, which elucidates the structure and composition of the synthesized nanoparticles.  
The XRD pattern reveals the cubic FCC structure of silver (Ag), as evidenced by the characteristic peaks corresponding to the JCPDF # 87-0598, with a theoretical lattice parameter of 2.31 nm. Based on the observed intensities in the experimental X-ray pattern, the symmetry associated with the Fm3m space group and the spatial group of 325 were determined. This result confirms the presence of the Fe\({}_{3}\)O\({}_{4}\) and Ag alloy, forming the synthesized nanoparticles. The subsequent evaluation of sample properties will be based on this confirmation.  
Furthermore, the XRD pattern displays prominent peaks corresponding to the cubic structure of Fe\({}_{3}\)O\({}_{4}\). Specifically, peaks corresponding to the (220), (311), (400), and (440) planes are observed at 20 angles of approximately 30\({}^{\circ}\), 35.4\({}^{\circ}\), 43.4\({}^{\circ}\), and 62.7\({}^{\circ}\), respectively (JCPDS card No. 19-0629). These findings further support the presence of Fe\({}_{3}\)O\({}_{4}\) within the synthesized nanoparticles, contributing to the comprehensive understanding of their structural characteristics.  
Figure 2: Chemical Analysis of Fe\({}_{3}\)O\({}_{4}\)-Ag Decorated Nanoparticles. (**a**) SE image of Fe\({}_{3}\)O\({}_{4}\). (**b**) Elemental mapping showing Ag distribution, confirming Fe\({}_{3}\)O\({}_{4}\)-Ag structure. Elemental mappings of Fe, O, and Ag from SE image of Fe\({}_{3}\)O\({}_{4}\) are in (**c–e**). (**f**) Chemical analysis confirms Fe, O, and Ag composition.
## Material and Methods
### Experimental Procedures  
Wistar rats with T1 DM (n = 20) were randomly divided into four groups: control group (CON), group treated with Coriander (COR), group exposed to 50 Hz of WBV (WBV), and treated with coriander and exposed to 50 Hz of WBV (COR + WBV). Along 28 days the CON group received by gavage [28] 1.0 mL of deionized water, while the group COR received by gavage 1.0 mL of aqueous extract at 8 mg/mL. In addition, the group WBV received 1.0 mL of deionized water and group COR + WBV received 1.0 mL of aqueous extract at 8 mg/mL, and then were submitted daily to vibration. Experimental procedures were applied for 5 days/week for 4 weeks. The experimental variables used in this current study were similar to our previous study [25].  
WBV exercise was applied every day between 11:00 and 12:00 through a vertically oscillating vibratory plate with the base oscillating up and down at the same time in a synchronous way (synchronous platform) (Globus G-Vibe 800, Italy). Sinusoidal vertical vibrations were generated with the following biomechanical variables: 50 Hz frequency, 0.78 mm amplitude, and peak acceleration of 7.85 g.
# Survey of Blockchain-Based Applications for IoT
## 2 Background
### Blockchain
While blockchains remain the dominant distributed ledger technology (DLT), alternative models such as IOTA's Tangle offer a different approach to achieving decentralized consensus, particularly in IoT applications [18]. By utilizing a Hash Directed Acyclic Graph (DAG), known as Tangle, instead of a blockchain, IOTA eliminates scalability and transaction fee issues, enabling peer-to-peer micropayments for IoT devices. Instead of relying on traditional consensus, unapproved transactions, known as \"tips\", must be approved by newly incoming transactions. Each new transaction selects two tips to validate using the Uniform Random Tip Selection strategy, which randomly picks from the available tips. \begin{table}
\begin{tabular}{c c c} \hline
**Algorithm** & **Description** & **Examples** \\ \hline Proof of Work (PoW) & Miners solve complex computational puzzles & Bitcoin, Ethereum (pre-Merge) [13] \\ \hline Proof of Stake (PoS) & Validators are selected based on the amount of stake & Ethereum (post-Merge) [13] \\ \hline Proof of Authority (PoA) & A small number of authorities validate transactions & VeChain [14] \\ \hline Practical Byzantine Fault Tolerance (PBFT) & Consensus by exchanging messages and agreeing on a majority & Hyperledger Fabric [15] \\ \hline \end{tabular}
\end{table} 
Table 1: Common consensus algorithms. Figure 3: Merkle Tree. However, this method introduces an issue, as transactions are not evenly distributed over time, leading to potential inefficiencies in approval propagation [18]. In this survey, we will only discuss blockchain technology and its applications, but IOTA is mentioned here as an alternative to blockchains.
## 5 Conclusions  
For this European dataset, incorporating a major drought event, we found good agreement between estimates of GPP inferred from eddy-covariance measurements and simulations generated using the P-model. We found that model error was higher under drought conditions as characterised by a standardised climatic index. For sparsely vegetated sites, simulations forced with land surface temperature did perform better than those forced with air temperature during periods of drought. However, our simulations, even driven by available LST estimates, do not yet reproduce the observed effects of drought on productivity.  
The P-model is under continual development. There are proposals for improved formulations of the effects of temperature and soil moisture, and consideration of the role of the diffuse radiation fraction. However, the guiding principle remains seeking simplicity and generality, rather than adding complexity. Assessed against global GPP data and evaluated in terms of functional relationships of GPP to key environmental drivers, the model already performs well in comparison to considerably more complex models [47], thus offering the initial basis for a well-founded, parameter-sparse global monitoring system for GPP.  
Conceptualization, I.C.P., R.v.H., M.B., I.A.J., S.V. and D.G.; methodology, R.v.H., M.B., D.G., K.J.B. and I.C.P.; validation, M.B., K.J.B. and I.C.P.; writing--original draft preparation, K.J.B.; writing--review and editing, all authors. All authors have read and agreed to the published version of the manuscript.  
This work received funding from the European Space Agency under the project \"Development and validation of a global GPP/NPP model using MERIS and Sentinel-3 data (TerrA-P)\", (ESA Contract No. 4000118570/16/I-NB, S3-4 SCI LAND).  
All data used in the analysis are publicly available--relevant links are detailed in Section 2.  
This work draws on the eddy covariance Warm Winter 2020 data collection acquired and shared by the ICOS community. The eddy covariance data processing and harmonisation were carried out by the ICOS Ecosystem Thematic Centre. The authors acknowledge the PIs of the eddy covariance sites and all technicians and researchers for providing their data and support to the ICOS Warm Winter 2020 dataset.  
The authors declare no conflict of interest.
## 4 Results
### Hydrodynamic Response
#### 4.1.1 Verification of the Numerical Model  
In order to verify the presented formulations and the numerical procedure, the static and dynamic responses of the SFT are compared with finite element results from ABAQUS/Aqua, [PERSON] et al. [8]. For comparison purposes, the absolute displacement is defined as follows:  
\[D_{ABS}=\sqrt{q_{Y}{}^{2}+q_{Z}{}^{2}} \tag{13}\]  
where \(D_{ABS}\) is the absolute displacement. The same definition is valid for both static and dynamic displacement. In the dynamic analysis, the maximum \(Y\) and \(Z\) displacements were used for calculating the absolute displacements.  
Both static and dynamic absolute displacements based on the same input properties and cable configurations are compared with [8]. The comparisons of static and dynamic absolute displacements using mooring configurations C2 and C3 are shown in Figure 4a,b, respectively. The close agreement of the results shows the accuracy of the presented model.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Element** & **Parameter** & **Unit** & **Value** \\ \hline \multirow{8}{*}{Hydrodynamics} & Wave height (\(H\)) & m & 1 \\  & Time period (\(T\)) & s & 2.3 \\  & Surface current velocity (\(\dot{U}_{c}\)) & m/s & 0.1 \\  & Depth of water (\(h\)) & m & 30 \\  & Distance of SFT from free surface (\(h_{1}\)) & m & 2 \\  & Density of water (\(\rho_{w}\)) & kg/m\({}^{3}\) & 1050 \\  & Drag coefficient (\(C_{D}\)) & – & 1 \\  & Inertia coefficient (\(C_{M}\)) & – & 2 \\ \hline \end{tabular}
\end{table}
Table 2: _Cont._  
Figure 3: Hydrodynamic force time history per unit length of the SFT.
## 4 An Integer Programming Formulation
### Constraints and an Objective Function  
We now describe the (necessary) conditions to hold for a Tantrix solution as constraints of an integer program. Based on the rules of Tantrix, we introduce the following four constrains.  
**Constraint 1** (C1). Exactly one tile is placed on each place.  
**Constraint 2** (C2). Each tile is used exactly once.  
**Constraint 3** (C3). The color of a line of an edge that is on the boundary of a board is not the designated color.  
**Constraint 4** (C4). The colors of lines whose corresponding edges are touching each other have to match.  
Constraint 1 is required to hold for any place on a board that it cannot happen that no tiles or more than two tiles are placed, and it is represented by the following formula:  
C1: \(\sum_{i=1}^{n}\sum_{k=1}^{6}x_{ijk}=1\ \ \ (j=1,2,\ldots,n)\)  
Constraint 2 can be set since we distinguish all the tiles. Each tile \(i\) is used exactly once and this is formulated as follows:  
C2: \(\sum_{j=1}^{n}\sum_{k=1}^{6}x_{ijk}=1\ \ \ (i=1,2,\ldots,n)\)Constraint 3 implies that a line of the designated color of any tile cannot become adjacent to the boundary of a board, and it is expressed as follows:  
\[\text{C3:}\quad 1\leq y_{j\ell}\leq 2\quad(j=1,\ldots,n;\ \ell=1,\ldots,6;\ a(j,\ell)=0)\]  
Constraint 4 implies the rules 4 and 5 of Tantrix; that is, connect lines of the same color for every three colors. This condition is formulated as follows:  
\[\text{C4:}\quad y_{j\ell}=y_{j^{\prime}\ell^{\prime}}\quad(j,j^{\prime}=1, \ldots,n;\ \ell,\ell^{\prime}=1,\ldots,6;\ a(j,\ell)=j^{\prime};\ a(j^{\prime},\ell^{ \prime})\ =\ j\ )\]  
Remark here that, by C3 and C4, any line of the designated color must be a part of a loop, that is, they constitute a necessary and sufficient condition for that all the lines of the designated color form loops.  
We call a loop of the designated color consists of less than \(n\) tiles a _subloop_. Then by C1-C4 we cannot avoid subloops. That is, they do not imply sufficient conditions that a loop of the designated color is unique, which must be satisfied by a Tantrix solution. It is, of course, not impossible to introduce constraints that eliminates all the probable subloops in a formulation as it is introduced for TSP formulations [16; 17; 20; 21], however, it may require exponential number of constraints, which may also cause a long computational time. Therefore, to guarantee the uniqueness of the loop of the designated color, in our formulation, we add constraints for eliminating subloops every time they appear and _re-solve_ it.  
In our approach, since a (Tantrix) solution is formulated as constraints of an integer program, it suffices to find one of its feasible solutions. In such a case, an objective function is enough to be virtual, and therefore, we set it as \(x_{1,1,1}\rightarrow\min\), for a descriptive purpose.
## 3 Results and Analysis
### Disc Cutter Wear Analysis
#### 3.1.2 Cutting Edge Rounding (CER)  
The CER was measured at the end of each round of wear experiments, and significant wear was observed on the overall cutting edge of the disc cutter; i.e., the cutting edge became blunt. In order to avoid the deviation of the experimental results, measurement and counting of only the cutting edges where wear occurred, cutting edge wear morphologies, and the variation of CER are shown in Figures 10 and 11. During the cutting process, the rake face and flank face of the cutting edge on both sides were continuously worn, and the CER became larger and tended to increase. When the cutting length was 23.25 m, the disc cutter was in the initial wear stage, and the cutting edge of the disc cutter was sharp. The disc cutter was in contact with the honeycomb surface in a small area, and the strong, tough aramid fiber and the brittle phenolic resin layer had more contact pressure on the disc cutter along the radial direction, which made the cutting edge of the disc cutter wear faster and the CER increase from 3.54 m to 6.74 m. In addition, under the action of longitudinal high-frequency ultrasonic vibration, the cutting edge was constantly subjected to periodic impact stress, which made the cutting edge wear and even break. Especially in the moment of contact with the honeycomb hole grid before each cut of the disc cutter, high-frequency ultrasonic vibration made the cutting edge of the disc cutter constantly scrape on the honeycomb wall, which made the cutting edge of the disc cutter constantly wear. As the cutting length increased from 46.50 m to 93.00 m, the CER increased more slowly from 6.74 m to 8.26 m.
# Rotation Accuracy Analysis of Aerostatic Spindle Considering Shaft's Roundness and Cylindricity
## 4 Results and Discussions
### Evaluation with Dispersion Coefficient  
The shape of the shaft determines the gas film thickness between the shaft and the matched bearing. The more uniform the film thickness, the smaller the pressure fluctuation in the shaft; therefore, the discrete coefficient index of shaft radius can be used to quantify the section shape of the shaft. The calculation is conducted by means of Equation (28):  
\[V_{S}=\frac{1}{r_{0}}\sqrt{\frac{1}{n-1}\sum_{i=1}^{n}\left(r_{i}-r_{0}\right) ^{2}} \tag{28}\]  
where \(n\) is the node number of single section, \(r_{i}\) is the radius of the shaft at the \(i\)-th node, and \(r_{0}\) is the average radius of the shaft in the current section.  
The radius dispersion coefficients of all sections are calculated using Equation (28) and the results are plotted in Figure 14. It can be seen that the dispersion coefficients of all sections of shaft 2 are significantly larger than those of the other three shafts, which indicates that there are great fluctuations in radius for each section of shaft 2. The particularity results here are consistent with those shown in Figures 7, 8 and 11. Although the roundness errors of section 19 of shaft 2 and section 10 of shaft 4 are identical, the differences in the dispersion coefficients shown in Figure 14 are significant. Therefore, it is not reliable to infer the shaft's rotational accuracy based on only its roundness and cylindricity errors.  
To further study this problem, sections with similar roundness errors (see Table 2) and similar discrete coefficients (see Table 3) are found from all cross sections of four shafts  
Figure 12: Roundness errors of four shafts.  
Figure 13: Composite drawing of roundness error for section 19 of shaft 2 and section 10 of shaft 4.  
It can be observed from Figure 16a that, although these shafts have the same roundness, the unbalanced film forces of these four shafts are quite different. The order of the force from large to small is section 19 of shaft 2 > section 7 of shaft 1 > section 10 of shaft 4 > section 1 of shaft 3, which is consistent with the order of the discrete coefficients in Table 2. As presented in Figure 16b, for the similar dispersion coefficient, the forces of the four shafts are generally similar, the lowest of which is for section 2 of shaft 1. In Table 3, the roundness errors of section 2 of shaft 1 is the largest among the four ideal shafts, but its discrete coefficient is the smallest. It can be proved that, compared with roundness errors, the discrete coefficient can be used more reliably to predict the unbalanced film force generated by the shaft due to the shape errors. In addition, when the results are combined with the data in Tables 2 and 3, it can be seen that if the roundness is similar, the discrete coefficient may be very different, but if the discrete coefficient is similar, the roundness difference is not large, so the discrete coefficient can be used to evaluate the processing quality of the shaft.
## 2 Signal Generators and System Description  
The proposed hybrid optical CDMA/DWDM system's operational diagram is shown in Figure 1, which consists of \(K\) number of channels (i.e., channels) spaced by 0.2 nm at a data rate of 40 Gbps per channel, where each is split into \(M\) branches, and each branch represents one user's data. The user's data are modulated to generate an RZ/CSRZ and MD-RZ optical signal, which then moves to optical CDMA encoding using a multi-diagonal (MD) sequence code. Interested readers may refer to [26; 27; 28] for more information about the generation of RZ, MDRZ, and CSRZ. The \(M\) optical CDMA users' data are combined by an optical combiner. Then the \(K\) channels are multiplexed by the WDM multiplexer followed by EOPM to modulate simultaneously the signal's phase at frequency equal to a single channel's data rate. Further details about the function of EOPM are reported in ref. [19]. The output of the EOPM is then launched into single mode fiber + dispersion compensating fiber (SMF + DCF) followed by a preamplifier to compensate the loss. Noting that each channel could support \(M\) number of optical CDMA users, the total number of users that the proposed hybrid system can accommodate is \(K\times M\) users.
# Design of a Digital Array Signal Processing System with Full Array Element
###### Abstract  
For the application of a digital array signal processing system with a high sampling rate and large bandwidth, and considering the constraints of limited resources (performance, volume, power consumption, weight, etc.), this paper proposes a design and implementation method of broadband digital array signal processing system based on radio frequency system on a chip. The system focuses on multi-channel synchronization under a high sampling rate and multi-channel amplitude and phase calibration under large bandwidth to form an all-digital, low-power, multi-channel, high-speed, large bandwidth hardware platform suitable for broadband digital array signal processing. Through the implementation of the Multiple-Input Multiple-Output phased-array digital beamforming algorithm, the test conducted verifies that the system has superior signal processing performance of the broadband digital array.  
radio frequency system on chip; high sampling rate; large bandwidth; digital array Article  
Design of a Digital Array Signal Processing System with Full Array Element  
11 August202311 August202  
At present, there is a system scheme that uses two channels to generate large instantaneous bandwidth radar signals [11] that occupy more channels and makes it difficult to meet the application scenarios of multi-channel radar systems. There is also a design solution that uses the discrete device approach of high-speed Analog-to-Digital Converter (ADC) and Digital-to-Analog Converter (DAC) chips combined with Field Programmable Gate Arrays (FPGAs) [12]. Its system has a larger size and greater power consumption, and the ADC/DAC consumes a large amount of high-speed interface, which puts higher demands on the FPGA resources.  
As the armed system is given higher index requirements, the performance requirement of the radar system is also higher. For the MIMO and phased array radar system, the number of channels and the volume also increase. Meanwhile, a large instantaneous bandwidth of the signal is required to improve the accuracy of a radar in the range and bearing dimensions and to classify and identify multiple targets. To address the above needs and embrace future development trends based on the on-chip RF integrated system chip (RFSoC), this paper adopts the high intermediate frequency (HIF) architecture and combines multi-channel synchronization with calibration techniques under a high sampling rate and a large bandwidth to design an all-digital, low-power, multi-channel, high-speed broadband digital array signal processing system with 64 receive channels and 64 transmit channels in a small volume to form a hardware platform for multi-channel radar system application and meet the application requirements of high performance and small volume.