esa-sceva/satcom-chunk-collection huggingface dataset:
## 1 Introduction
### Analysis of Block Boundary Cracking  
The discontinuous jointed rock mass is discretized into fine triangular block grids by the block automatic generation algorithm. The boundary of the triangular block grids, the virtual joints, provides a path for crack propagation. The triangular block grids on both sides of the virtual joints are bonded by the sticky settlement method. If the two grids are in contact, they need to add normal and tangential contact springs to prevent normal insertion and tangential slip. If the contact spring force exceeds the joint strength, the contact springs are removed and the two grids can move separately. Therefore, the restraint of the spring can be maintained by increasing the joint strength parameters so that the two grids are bonded together. It is based on this idea that the strength parameters of virtual joints are increased to achieve bonding between grids. If the relative displacement of the grids on both sides of the virtual joint is too large, and the contact force of the spring reaches the strength of the rock, the contact spring is destroyed, and the virtual joint becomes a real joint to form a crack, and the real joint strength parameters are assigned to it. In this way, the simulation of crack propagation is realized.  
The failure of the contact spring is judged by two criteria: normal tension failure and tangential compression-shear failure. The failure criterion of a normal spring is that when the maximum tensile principal stress reaches a given value, the spring fails. The tangential compression-shear failure criterion considers that when the spring meets the Mohr-Coulomb criterion, the spring fails. At the same time, the tensile failure criterion has priority. If the tensile failure criterion is satisfied, it is not necessary to judge whether the compression-shear failure criterion is satisfied. Only if the tensile criterion is not satisfied can the compression-shear failure criterion be determined. The normal spring tensile failure criterion is as follows:  
\[f_{n}=-T_{0}l \tag{1}\]  
The tangential spring compression-shear failure criterion is as follows:  
\[f_{r}=cl+f_{n}\tan\varphi \tag{2}\]  
Terms in the equation: \(f_{n}\)--Normal contact force; \(f_{r}\)--Tangential contact force; \(T_{0}\)--Uniaxial tensile strength of the rock; c--Cohesion of the rock; \(\varphi\)--Friction angle of the rock; and l--Length of contact.  
According to the contact force and failure criteria calculated by Equations (1) and (2), it can be judged as to whether the contact spring is damaged or not. If it is damaged, the virtual joint becomes the real one and its strength decreases to the strength of the real one (pp. 40-41, [8]).
# Investigation of the Effect of Capillary Barrier on Water-Oil Movement in Water Flooding
## 4 Effect of the Capillary Barrier on Oil-Water Two-Phase Flow in Porous Media Model  
### Physical Model and Case Setup  
In order to investigate the influence of the capillary barrier effect on oil-water two-phase flow and the oil displacement efficiency at a macroscopic scale, a two-dimensional porous media model with opening angle \(45^{\circ}\) is constructed in this paper based on the proposed capillary barrier model, which is shown in Figure 16. The shape of the pore cavity is a symmetrical octagon, and the length of each four wall edges is \(40\sqrt{2}\times 10^{-6}\) m. The angle between the wall and the opening edge is \(135^{\circ}\) to ensure the opening angle is \(45^{\circ}\). The length of the throat section is \(40\times 10^{-5}\) m. The opening at the bottom left is the injection inlet of the water phase and the opening at the upper right is the outlet of the oil.  
It should be stressed that the 2D model used here is different from the cylindrical model discussed above. The capillary force of a cylinder model (with radius \(r\)) should be two times that of a 2D model (with width \(2r\)). Thus, in the simulation with the 2D model, the capillary force should be decreased by half relative to that with the cylinder model. However, the size of the pore channels used in the 2d model will not influence the occurrence of the capillary barriers. The capillary barrier criterion is only related to the contact angle and open angle but not the pore radius. Thus, the effect of the capillary  
Figure 15: The distribution of the maximum (**a**) and minimum (**b**) capillary force varying with contact angle \(\theta\) and opening angle \(\beta\) under oil-wet conditions.  
barrier on the pore-scale flow behaviors should be captured using a 2D model and it is adopted for its simplicity.  
It is reasonable to adopt a structured grid to simulate the oil-water flow dynamics in this porous media model. In the process of the structured grid generation, an opening edge and a wall edge of the pore cavity is considered as a set, the grid number at each edge is 20, and the total grid number is 2.2 \(\times\) 10\({}^{6}\). The parameters used in the simulation are listed in Table 4. Among the parameters, \(|\mathbf{v}|\) is the velocity scalar of the water injection, \(v_{x}\), \(v_{y}\) are the velocity components of the injection velocity of water phase in the x-y plane, \(\sigma\) is the surface tension coefficient, \(\rho_{oil}\) and \(\rho_{water}\) represent the density of the oil and the water, \(\mu_{oil}\) and \(\mu_{water}\) are the viscosity of the oil and water. Seven values of the contact angle (15\({}^{\circ}\), 30\({}^{\circ}\), 45\({}^{\circ}\), 60\({}^{\circ}\), 90\({}^{\circ}\), 120\({}^{\circ}\), 165\({}^{\circ}\)) are adopted in this simulation.
# An Evaluation of the Effects of a Virtual Museum on Users' Attitudes towards Cultural Heritage
## 4 Results
### Attitudes
#### 4.2.2 Attitudes towards the Multimedia Experience  
In the case of the index of attitudes towards the multimedia experience, a main effect for psychological presence (B = 0.3837, t(97) = 3.11, \(p\) = 0.002, CI [0.13, 0.62]) and direction of thoughts (B = 1.3645, t(97) = 2.96, \(p\) = 0.003, CI [0.45, 2.27]) on attitudes were found. This means that greater levels of presence predicted a more positive attitude toward the multimedia experience, and more positive thoughts about the experience predicted a more positive attitudes toward the multimedia experience.  
No main effect for type of virtual experience was found (B = \(-\)0.0794, t(97) = \(-\)0.13, \(p\) = 0.89, CI [\(-\)1.26, 1.10]). No interaction effects were found between presence and direction of thoughts (B = \(-\)0.2046, t(97) = \(-\)1.46, \(p\) = 0.14, CI [\(-\)0.48, 0.07]), presence and device used (B = 0.1372, t(97) = 0.73, \(p\) = 0.46, CI [\(-\) 0.23, 0.50]), and direction of thoughts and device used (B = 1.1802, t(97) = 1.64, \(p\) = 0.10, CI [\(-\)0.24, 2.60]).  
No triple interaction between psychological presence, direction of thoughts and type of multimedia experience on the attitudes toward the multimedia experience was found (B = \(-\)0.325, t(97) = \(-\)1.54, \(p\) = 0.12, CI [\(-\)0.75, 0.09]; see Figure 5). However, as can be seen in Figure 5, there are similar tendencies than the overall index results.  
Figure 4: General attitudes according to reported levels of psychological presence and direction of thoughts.
## 3 Results and Discussion
### Determining the Optimum Cutting Parameters  
To determine the optimum cutting parameters, the ANOVA values for S/N ratios were calculated as shown in Table 7. Based on that, the main effect plots of cutting parameters for S/N ratios were determined as illustrated in Figure 3.  
Figure 3 indicates the main effect plots for the grinding time which clearly shows that the 3 rd level of cutting depth (0.03 mm), 3 rd level of wheel speed (5000 rpm) and 3 rd level of feed rate (3500 mm/min) were the optimum values of cutting parameters for the grinding time. These values would help to get the least grinding time.  
\begin{table}
\begin{tabular}{c c c c c c c|c c c} \hline \hline \multicolumn{1}{c}{} & \multicolumn{4}{c|}{**Analysis of Variance for SN Retios**} & \multicolumn{4}{c}{**Model Summary**} \\ \hline
**Source** & **DF** & **Seq SS** & **Adj SS** & **Adj MS** & **F** & **P** & **S** & **R-Sq** & **R-Sq (adj)** \\ \hline
**a**ed & 2 & 9.5112 & 9.5112 & 4.75561 & 185818.41 & 0.000 & 0.0051 & 100.00\% & 100.00\% \\ \hline RPM & 2 & 0.0001 & 0.0001 & 0.00006 & 2.18 & 0.314 & & & \\ \hline F\({}_{\rm e}\) & 2 & 12.0185 & 12.0185 & 0.00924 & 234802.40 & 0.000 & & & \\ \hline Residual Error & 2 & 0.0001 & 0.0001 & 0.00003 & & & & \\ \hline Total & 8 & 21.5299 & & & & & & \\ \hline \end{tabular}
\end{table}
Table 7: The ANOVA values for S/N ratios.  
Figure 3: Main effect plots of cutting parameters for S/N ratios.  
Figure 2: Main effect plots of cutting parameters for means of grinding time (\(t\)).
## 5 Conclusions  
In this paper, semiconductive layers with different contents of LSC were prepared by melt blending. The appearance and resistivity of the nanocomposites and their effects on space charge injection of insulating layers were studied. The conclusions are drawn as follows:  
1. When the LSC content in the semiconductive composites is low, the nanoparticles are uniformly dispersed in the matrix, and when the content of the nanoparticles increases, agglomeration occurs.  
Figure 14: Schematic diagram of electron trapping.  
The addition of LSC can suppress the PTC effect of the semiconducting layer. When the LSC content is 1 wt%, the PTC strength of semiconducting shielding layer decreased from 1.47 to 0.99, decreasing by 38.1%. This is because the LSC doped in semiconductive materials is an ionic conductor, and the mobility of carriers increases with the increase in temperature.
* The experimental results show that when the doping amount of LSC is 1 wt%, the charge amount in the insulating sample is the smallest, which is \(0.75\times 10^{-9}\), \(1.34\times 10^{-9}\), and \(2.75\times 10^{-9}\), respectively, decreasing by 44.4%, 58.9%, and 35.7%. This is because the charge is subjected to the Coulomb force of the LSC particles in the semiconductive layer, which reduces the charge injection from the metal electrode to the insulating layer.  
Conceptualization, C.H. and Y.C.; methodology, H.Y.; software, X.G. and S.Z.; validation, Y.W., G.L. and M.X.; writing--original draft preparation, Y.C.; writing--review and editing, C.H. and Y.C.; funding acquisition, Q.L. and Z.X. All authors read and agreed to the published version of the manuscript.  
This research was funded by [the State Key Laboratory of Advanced Power Transmission Technology] grant number [SGGR0000 DWJS1800561] and [State Grid Shandong Electric Power Research Institute] grant number [SGSDDK00 KJ]S1900329].  
The authors declare no conflict of interest.
## 2 Materials and Methods  
### Electrodes Manufacturing and Activation  
The electrodes were created using additive manufacturing (AM) with a fused deposition modelling (FDM) technique. The geometry of the electrodes, as shown in Figure 1, was designed to facilitate wiring and to facilitate subsequent experimentation. The printer used was a Prusa i3 (RepRep). In order to manufacture the electrodes, it was necessary to use a computer-assisted design (CAD) model and generate a standard triangle language (STL) file. Subsequently, the piece was manufactured by depositing a fused polymeric compound. In this study, graphene-loaded polylactic acid (PLA/graphene, Black Magic 3D, New York) was used as a printing material. We opted for PLA because it is one of the most popular materials used in desktop 3D printing (the graphene provides conductivity; volume conductivity: 1.7 S cm\({}^{-1}\)). The filament (1.75 mm diameter) passed through a 0.4 mm diameter nozzle, the working temperature of which was 200 \({}^{\circ}\)C. Finally, the polymer was deposited layer by layer on the working surface of the machine. The working bed was tempered to 50 \({}^{\circ}\)C during the entire manufacturing process. The printing parameters for successful manufacture of the parts were as follows: (i) layer height of 0.2 mm, (ii) a linear pattern with a 40% infill, and (iii) a printing speed of 2000 mm\(\cdot\)min\({}^{-1}\). Three activation procedures were essayed: electrochemical, chemical using dimethylformamide (DMF) as solvent, and chemical using acetone as solvent. The control electrode was gently cleaned with deionized water after manufacturing, but it underwent no activation procedure. Electrochemical activation was done in phosphate buffer solution (pH 7) by applying a cell potential of 2.5 V during 250 s in a two-electrode arrangement. The counter electrode was a platinum mesh (Goodfellow, PA, USA). DMF and acetone activation were performed by soaking the electrodes in the respective pure solvent (Sigma Aldrich, MO, USA) for 60 s and then removing the solvent by rinsing profusely with deionized water. Immersion times of more than 120 s in both DMF and acetone caused the destruction of the electrodes. The pre-treatment procedures were adapted from those proposed by [PERSON] et al. [12], who pointed out DMF and acetone as suitable activation agents, and [PERSON] et al. [13], who described the electrochemical activation procedure.
## 5 Conclusions  
This paper proposed a variable thickness MR transmission device controlled by electrothermal SMA springs, which realizes a double-disc transmission and employs an electrothermal SMA spring to change the MRF working gap thickness and control the transmission torque. This paper also performed a theoretical analysis of the magnetic circuit and magnetic field distribution of the MRF transmission device, and a theoretical deduction and calculation of the squeezing force output by the electrothermal SMA spring and the transfer torque of the variable thickness MRF transmission device. The findings indicated that:  
1. The output squeeze force of the SMA spring showed a high degree of nonlinearity during the temperature rise, with a maximum squeeze force of 318.43 N. When the current of the electrothermal SMA spring was 3 A, the highest heating temperature of the spring could reach the end of austenite phase transformation temperature. The current size affects the phase transformation process of the SMA to some extent, resulting in differences in the growth trajectory of the spring's restoring force.
2. Thickness variation had a small effect on the integral number of MRF, but excessive shear deformation leading to magnetic chain breakage was the main factor affecting the performance failure of MRF. The shear stress under squeeze conditions was mainly composed of two parts: magnetic shear stress of dipole and friction stress between particles. When the MRF was axially pressurized, the magnetic chain gradually changed from a single-chain model to a body-centered cubic model, along with the reduction of the particle gap. The squeeze strengthening effect of MRF is related to the magnetic induction strength and squeezing pressure. When the squeezing pressure is fixed, the higher the magnetic induction strength, and the more significant the strengthening effect.
3. The torque of MR transmission device showed an approximately linear increase with the increase of the spring current, and the maximum MRF torque was 73.56 N\(\cdot\)m at the current of 3.0 A and the squeeze stress of 0.34 MPa, and the performance of MRF was enhanced by 4.88 times after squeeze strengthening.  
[PERSON] and [PERSON] conceived this research; [PERSON] and [PERSON] performed the calculations; [PERSON] and [PERSON] wrote the original draft of the manuscript; [PERSON] and [PERSON] edited and reviewed the manuscript; [PERSON] oversaw the progress of the study and the visualization of the results. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China under Grant No. 51875068, the Youth Project of Science and Technology Research Program of Chongqing Education Commission of China under Grant No. KJQN201901120, and the Natural Science Foundation Project of Chongqing Science and Technology Commission (cstc2020)cyj-mssmx00402).
# Molecular Mechanisms of Topography Sensing by Osteoblasts: An Update
## 2 Influence of Topography on Cells
### Ordered Topographies
To go deeper in the rationalization of topographical design, high throughput approaches have been implemented with the design of so-called \"TopoChip\". These surfaces present a large number of randomly produced patterns from the combination of basic geometrical elements [51]. Topographies promoting thin and stretched cells, with low solidity and high compactness are better at promoting osteogenicity and this effect is mostly encountered in topography with high pattern area and low wavenumber. This systematic approach has the great advantage of predicting which kinds of patterns and which kinds of associatedcellular morphologies are able to lead to higher osteogenic marker expression, matrix mineralization and implant osseointegration. A very interesting feature of grooves and ridges is their anisotropy. Isotropic surfaces like Petri dishes, rough surfaces or microdots do not present a principal orientation. By contrast, parallel grooves and ridges define a longitudinal axis (along the grooves) and a transversal axis (across the grooves). One of the most consistent effects of contact guidance across all cell types is that cells orientate, elongate, and migrate along the longitudinal axis of anisotropic surfaces [52; 53]. Reports indicate that cell alignment may lead in certain conditions to the deposition of an oriented ECM [54]. Importantly, bone is also an anisotropic tissue with a complex system of preferential orientations at different scales, and the orientation of collagens fibers and/or HA crystals is important for the mechanical properties of the mature tissues [55]. Therefore, this leads to a crucial bioengineering question: can anisotropic topography lead to the production of aligned collagen and, subsequently, oriented mineralized ECM? Osteoblasts cultivated on grooved substrates do align with the surface longitudinal axis consistently with the data known for other cell types [41; 42]. However, more investigations are needed at the molecular level to determine whether the cell alignment is correlated with the alignment of collagen and/or HA crystals. [PERSON] and colleagues observed the expected alignment of primary osteoblasts with the longitudinal axis of nanometric grooves and ridges. However, they interestingly noticed a transversal alignment of collagen fibers and apatite crystals [56]. This surprising matrix orientation was further correlated with the expression of the gene tspan11 coding for a tetraspanin-family protein [57]. Cells knocked-down for tspan11 show less alignment with the surface grooves and less orthogonal orientation of collagen fibers. Unfortunately, we do not know whether HA crystals in the ECM from tspan11 knocked-down cells also lost the orthogonal orientation. Although we do not have a mechanism explaining the peculiar orientation of the mineralized matrix, these results highlight the importance of the question of topography-induced anisotropic bone matrix formation and the need for further investigations.
###### Abstract  
Peri-implantitis management could be performed either with a surgical or non-surgical approach to the implant surfaces. Various treatment options have been proposed in the literature, such as antiseptic and antibiotic therapies, chemical agents, curettes, ultrasonic, air abrasive, rotary titanium brushes and laser treatments; in particular, photodynamic therapy combined with hydrogen peroxide (OHLLT) has proved to be efficient in the removal of bacterial biofilm from implant surfaces. The aim of our study is to compare OHLLT performed with a surgical approach to a non-surgical approach. We selected a cluster of 227 implants affected by peri-implantitis: 139 implants were treated with a non-surgical approach and 88 implants with a surgical approach. Bone loss pre-operative and post-operative (with a follow-up of five years) have been registered. The collected data were entered on the Statistical Package for Social Sciences (SPSS) version 11.5. The results indicate a statistically significant difference between the two groups, with a mean bone loss after treatment of 2.3 mm for OHLLT with a surgical approach and 3.8 mm for OHLLT with a non-surgical approach; according to the Kolmogorov-Smirnov test, the overall data followed a normal distribution (value of the Kolmogorov-Smirnov test statistic = 0.0891; \(p\) = 0.35794). Thus, a surgical approach in the case of peri-implantitis seems to be more effective, probably due to the possibility of a deeper sanitization of implant surfaces, hardly reachable with only non-surgical approach.  
diode laser; high frequency; hydrogen peroxide; peri-implantitis; photodynamic therapy 2021
## 4 Experimental Results and Analysis  
### Load-Strain Curves  
#### 4.1.1 Concentrically Loaded Specim  
Figure 6 shows the load-strain curves of concentrically loaded specimens, where \(\varepsilon_{1}\) and \(\varepsilon_{2}\) are the longitudinal strain and transverse strain of concave side of mid-section, \(\varepsilon_{3}\) and \(\varepsilon_{4}\) are the longitudinal strain and transverse strain of convex side of mid-section, and the measured yield strain \(\varepsilon_{y}\) is 1650 \(\imath\varepsilon\). It can be seen that the strain change laws of specimens are basically the same. During the elastic phase, the strain of mid-section is synchronously increased, longitudinally compressed, and circumferentially tensioned. After entering the elastic-plastic stage, the stress state begins to change, the longitudinal compressive strain and the transverse tensile strain of convex side gradually decrease, while the longitudinal compressive strain and transverse tensile strain of concave side continue to increase, which is due to the additional bending moment caused by the second-order effect of member flexure. After the peak load, the longitudinal strain of the convex side gradually changes from compressive strain to tensile strain, and the transverse strain gradually changes from tensile strain to compressive strain. The longitudinal compressive strain and transverse tensile strain of concave side continue to increase. At peak load, the strain of each specimen is in the elastic-plastic stage.  
Figure 5: Experimental phenomena of the specimen C15-90: (**a**) elastic stage; (**b**) failure stage; and (**c**) rust peeling.
## 3 Results and Discussions
### FTIR Spectra Analysis
Vibration modes different to what was reported for the Murchison and Bells meteorites complete those already reported by [PERSON] et al. [7], for the aromatic structures. Organic kerogen-like matter, referred to as \"Murchison Insoluble Organic Material (IOM)\" by [PERSON] et al. [8], is evidenced when corroborating the FTIR spectra with the high insolubility of samples P1 and P2 in water and alcohol, as presented before. The chemical components identified by FTIR spectroscopy are also confirmed by EDS elemental analysis and XRD, the latter evidencing the crystalline structures of calcium carbonate (CaCO3, CaSO4 and SiO2).