esa-sceva/satcom-chunk-collection huggingface dataset:
# Numerical Insight into the Kelvin-Helmholtz Instability Appearance in Cavitating Flow
## 3 Numerical Procedure
### Two-Phase Flow Modeling  
We more commonly use the concept of the homogeneous flow of the mixture for cavitation simulation, where the two-phase flow is assumed to be a single-phase flow of the liquid-vapor mixture. This helps one to solve only one motion equation since we consider the problem as a single-phase, but with the mixture's properties. Accordingly, the properties of the liquid-vapor mixture are described by the proportion of the vapor phase, using the model suggested by [PERSON] [21]. The mixture's density is written:  
\[\rho_{m}=\alpha\rho_{v}+(1-\alpha)\rho_{l} \tag{5}\]  
where \(\alpha\) denotes vapor volume fraction, and mixture's dynamic viscosity is written as:  
\[\mu_{m}=\alpha\mu_{v}+(1-\alpha)\mu_{l} \tag{6}\]  
The equations of mass and momentum conservation are resolved in the model of the homogeneous flow of the mixture by the properties of the mixture, and the equation of phase fraction conservation must be solved:  
\[\frac{\partial}{\partial t}(\rho_{v}\alpha)+\
abla\cdot(\rho_{v}\alpha\mathbf{u} _{v})=R_{e}-R_{c} \tag{7}\]  
where \(R_{e}\) and \(R_{c}\) represent mass transfer source terms for evaporation and condensation, which account for the mass transfer between the phases of liquid and vapor in cavitation and are thus related to the growth and collapse of the vapor bubbles. According to the cavitation model used, their formulation varies.
## 8 Discussion and Implications
#### Limitations  
There are limitations to this exploratory approach to studying digital inequality in China in 2020. First of all, because most provinces in China are large and populous geographic areas, uneven intra-provincial digital development is common. The analysis at the provincial level cannot reveal the hidden patterns at a granular scale. Another limitation is that the variable choice depends on the China Yearbooks, which do not collect some well-known variables of importance in the digital divide literature, such as social media factors, social capital, detailed ethnic groupings, telecom regulations, the rule of law, and freedom.
## 3 Numerical Modeling
### Optimal Test Conditions  
[PERSON] et al. [8] in their work did not study the impact of the arch loading on the indirect tensile strength of the concrete and mortar disks and their study was limited to an arch loading 2\(\alpha\) = 20\({}^{\circ}\). As indicated by [PERSON] et al. [6], the first failure and/or crack initiation occurred at the center of the disk in all loading arch simulations (Figure 5). Moreover, the  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Loading Arch Angle (\({}^{\circ}\))** & **[PERSON] et al. [8]** & **[PERSON] et al. [7]** & \multicolumn{2}{c}{**Present Analysis**} \\ \cline{2-5}  & **Numerical** & **Analytical** \\ \hline Concrete & 2.25–2.73 & 2.5–2.4 & 2.500 & 2.609 \\ Mortar & 3.44–3.56 & 3.4–3.2 & 3.500 & 3.654 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Predicted indirect tensile strength \(\sigma_{t}\) (MPa) compared to [7; 8] (2\(\alpha\) = 20\({}^{\circ}\)).  
Figure 5: (**a**) Arch loading angle 2\(\alpha\) = 15\({}^{\circ}\). (**b**) Arch loading angle 2\(\alpha\) = 20\({}^{\circ}\)(**c**) Arch loading angle 2\(\alpha\) = 30\({}^{\circ}\). Numerical Distribution of maximum shear strains, crack initiation point positions, and applied pressure in the disk tested by [6].  
good agreement of the numerical results in comparison with [6; 7; 8] allows us to confirm the capacity of our model to analyze and to determine the indirect tensile stress in the Brazilian disk under various loading arch.  
Valuable studies showed that the arch loading angle has a great effect on the validity of the Brazilian test. Furthermore, the purpose of this work is to determine the values of loading arch under which the test is successful for concrete and mortar disks.  
In order to recommend the best loading configuration which gives a successful test with a correct estimation of the indirect tensile strength of concrete and mortar, the influence of arch loading angle and initial cracks position point on the success of the disks of concrete and mortar tested by [PERSON] et al. [8] under loading arch \(2\alpha\), which varies from 5-45\({}^{\circ}\), was investigated using numerical software FLAC\({}^{\text{2D}}\)[21]. The ratio \(\sigma_{c}^{G}/\sigma_{t}^{G}\) is calculated for all simulated loading cases.  
Consequently, numerical simulations of the Brazilian test were conducted of a concrete and mortar disk with a diameter of 70 mm [8], varying the loading angle from 5-45\({}^{\circ}\) in order to see its influence on the position of the initiation of the cracks and consequently on the validity of the test. The numerical input of the simulated disks are shown in Table 3.
# A Comprehensive Review of Micro UAV Charging Techniques
## 8 Potential Challenges in UAV Charging Techniques
### Efficiency Improvement Issue  
The efficiency of laser power transfer is a challenging issue. With the growing developments in LPT, its applications are increasing. The overall efficiency is not sufficient for commercial developments. The research community is working on efficiency improvement for commercial applications. Mainly researchers are focusing on enhancing PV cell efficiency. Meanwhile, researchers have also shown limited interest in optimizing lasers for power beaming.
# Scenario-Based Configuration Refinement for High-Load Cellular Networks: An Operator View
## 2 Analysis of High Traffic Load Cells
### Analysis Process and Refinement Principles  
As shown in Figure 4, we summarize the discussion in Sections 2.3 and 2.4 by proposing the main flow of analysis process and configuration refinement for cellular networks. More specifically, by jointly considering the comments from vendors and the field data collected from current cellular networks (as shown in Tables 1, 3 and 4), the MNOU and the PRB utilization ratio (or ANOU) are identified as the indicators of high traffic load macro cells and indoor distribution systems. For macro cells with high traffic loads, we can analyze traffic loads of neighbor cells and user distribution if the coverage of the current cell is not rational. For indoor distribution systems, the downstream traffic of remote radio unit(RRU) is analyzed if the traffic load is high. We categorize the case of high CPU utilization ratio into two folds that are high loads of UMPT and LBBP. Single unit analysis is conducted if the traffic load of UMPT is high, whereas the traffic load balance among different units is analyzed if the traffic load of LBBP is high. Traffic balance among units is carefully considered when the traffic load of LBBP is high. At the right side of Figure 4, we present different refinement policies corresponding to different cases. We present network configuration refinement of high traffic load cells in different scenarios using these policies in the following sections.  
Figure 3: Downlink PRB utilization ratio vs. downlink data rate of a single user.  
\begin{table}
\begin{tabular}{c c} \hline \hline \multirow{2}{*}{**ANOU and Downlink PRB Utilization Ratio**} & \multicolumn{2}{c}{**Percentage of Users**} \\  & **(Downlink Data Rate Lower than 3 Mbps)** \\ \hline
50, 40\(\sim\)50\% & 1.75\% \\
50, 50\(\sim\)60\% & 17.83\% \\
50, 60\(\sim\)70\% & 41.30\% \\
50, 70\(\sim\)80\% & 72.99\% \\
50, 80\(\sim\)100\% & 88.24\% \\ \hline \hline \end{tabular}
\end{table}
Table 5: ANOU/Downlink PRB utilization ratio vs. Percentage of cells with low data rate.
# Energy Sustainability in Wireless Sensor Networks: An Analytical Survey
## 3 Hardware-Based Energy Sustainability in WSNs
### Hardware-Based Methods for Energy Sustainability
#### 3.2.3 Wireless Energy Transfer  
Wireless energy transfer (WET) is another method used to increase energy residues of the nodes in WSNs. Actually, this method, is described as the ability of wirelessly transferring electrical energy among nodes by using appropriate hardware components [19]. When exploiting this method, energy may be transferred from the segments of the network with higher energy levels to segments having lower amounts of energy residues so as to balance the energy levels of the network [41]. Power transfer in a WSN can be accomplished using either stationary sources or mobile chargers. Energy is provided to the nodes via charging vehicles and robots, or energy transmitters. Furthermore, sensor nodes are capable of transferring energy to their neighboring nodes [42]. Energy wireless transfer can be achieved in three ways:  
* Inductive coupling: energy can be wirelessly transferred from a primary to a secondary coil that is placed in close distance. The amount of generated energy is proportional to the size of the coil. This method is simple and safe to apply [19];
* Magnetic resonant coupling: power is transferred from a main coil (source) to a secondary (receiver). This can be accomplished through the utilization of resonant coils that have the same resonant frequency and are either loosely or strongly coupled [42]. Compared to inductive coupling, this method provides the power transfer over longer distances, and it is not a radiative method. So, it causes almost no harm to humans and does not have need of line of sight;
* Electromagnetic (EM) radiation: a source device transmits energy via electromagnetic waves through its antenna to another device's receiving antenna. There are two types of electromagnetic radiation: omnidirectional and unidirectional. By using EM, energy can be transmitted over long distances [43].
###### Abstract  
This study aims to evaluate the potential of incorporating fly ash (FA) and municipal solid waste incinerator bottom ash (MIBA) as a partial substitute of cement in the production of self-compacting concrete mixes through an experimental campaign in which four replacement levels (i.e., 10% FA + 20% MIBA, 20% FA + 10% MIBA, 20% FA + 40% MIBA and 40% FA + 20% MIBA, apart from the reference concrete) were considered. Compressive and tensile strengths, Young's modulus, ultra-sonic pulse velocity, shrinkage, water absorption by immersion, chloride diffusion coefficient and electrical resistivity were evaluated for all concrete mixes. The results showed a considerable decline in both mechanical and durability-related performances of self-compacting concrete with 60% of substitution by MIBA mainly due to the aluminium corrosion chemical reaction. However, workability properties were not significantly affected, exhibiting values similar to those of the control mix.  
self-compacting concrete; fly ash; municipal solid waste; bottom ash; incineration Article
# Silver Nanowires: Synthesis, Antibacterialativity and Biomedical Applications
## 3 Mechanism of Antibacterial Activity
### Silver Nanowires Mechanism of Action
These results are particularly interesting, as AgNPs-loaded graphene oxide produced similar results to a commonly prescribed antibacterial therapeutic. Figure 2: TEM images of silver nanoparticles (**a**); silver nano cubes (**b**) and silver nanowires (**c**) and their respective interaction with _E. coli_ cells (**d**–**f**). [Reproduced from [34] with permission. Copyright (2016) Springer]. [PERSON] and [PERSON] also demonstrated mechanisms in which AgNWs and graphene oxide may elicit their antibacterial effect. They found that AgNWs, graphene oxide and AgNW-loaded graphene oxide all drastically increase the concentration of ROS in solution, and this contributed to _E. coli_ death. These results explain why the previous work by [PERSON] et al. [33] showed no significant difference between the ion-free-silver and silver ion-containing nanowire suspensions, because the process of bacterial cell death is produced via a combination of mechanisms as opposed to one single mechanism of action. Finally, the authors show that FESEM images of treated _E. coli_ cells exhibit high levels of cell membrane disruption and overall lysis, which would be consistent with the elevated levels of DNA, RNA and protein leakage and the decreased bioluminescence observed by [PERSON] et al. [33]. It is also important to note that [PERSON] and [PERSON] [36] observed that similar results against _S. aureus_, although the data is not shown, suggesting that these results apply to both Gram-negative and Gram-positive bacteria.
## 3 Experiments and Discussion
### Signal Transmission of BSN  
#### 3.2.1 Method  
In order to verify the functions and determine the suitable parameters of the proposed signal transmission system used in the BSN, the corresponding _in-vivo_ experiments with different carrier wave frequencies, baseband frequencies and multi-paths were implemented using the experimental device shown in Figure 7. Compared with the experimental device shown in Figure 5(a), a receiving circuit mentioned in Section 2.4, which includes a variable gain amplifier, a band pass filter and a FPGA module, was added to the experimental device. In our experiments, the signal \"1010101010\" was chosen as the baseband signal. In the FPGA module of the transmitter, the baseband signal was converted into the corresponding relocatable code singal (110011001100) first, and then it modulated the carrier wave signal with the DBPSK method. Subsequently, the modulated signal was coupled into the human body at the transmitting terminal and received by the proposed Mach-Zehnder EO sensor at the receiving terminal. Finally, the signal was processed and demodulated by the receiving circuit.
## 3 Results and Discussion
### Characterization of the MWCNTs
#### 3.1.3 SEM Examination  
The external morphology of the MWCNTs was examined by scanning electron microscopy. Figure 3A,B displays the SEM images as prepared and purified MWCNTs, respectively. These figures show greatly tangled tubes and the existence of amorphous carbon in the unpurified sample. This observation, after acid treatment, confirms the disappearance of the amorphous texture, and there is no evidence of damage to the tubular structure of the MWCNTs, nor did the multi-walled arrangement vary. The tubular diameter of the MWCNTs ranged between 75 and 100 nm.
# Backscatter Communications: Inception of the Battery-Free Era--A Comprehensive Survey
## 9 Challenges and Future Directions
### Open Problems
#### 9.1.5 Achieving High Data Rates  
Amb-BackCom enables tags to utilize available RF signals to modulate their information. The data rates of the backscattered signals are very low. [PERSON] et al. considered a data rate for BackCom of up to 1.6 bps [222], whereas a throughput of 1 kbps was achieved by [PERSON] et al. [12]. However, the increasing need of massive IoT in 5G networks require high data rate services, which seems very difficult for BackCom considering the limitations of telecommunication laws [224] in different regions of the world to enable mm-wave-based battery-free IoT communications.  
**Discussion:** BackCom is popular technology and has the potential to address the future needs of 5G and massive IoT connectivity with battery-less communications. Figure 49 demonstrates some challenges faced by BackCom. These are enumerated as follows:  
1. Interference management for a small powered BackCom network is hard to attain. The transmitting nodes are not able to communicate with the surrounding nodes, which causes all tags to transmit data simultaneously. Moreover, simultaneous data transmissions cause interference between backscattered signals of various nodes [77].
2. The eavesdropping attack in the BackCom system is a serious security threat to data carried by backscattered signals [109].
3. The communication range of backscattered signals is very less, which causes tags to communicate within a very narrow range. [129].
4. Networking among tiny powered nodes needs much attention. The networking schemes should support low energy and battery-less scenarios.
5. Achieving high data rates in BackCom can address the demands of future BackCom IoT devices [173].
# Numerical and Experimental Characterization of a Coanda-Type Industrial Air Amplifier
## 3 Experimental Setup
### Wake Velocity Measurements  
The velocity profile of the wake was explored using constant temperature anemometry (CTA) of a vertical array of points, repeated at several downstream locations of the isolated air amplifier. CTA is a measurement technique based on the cooling effect of a flow on a preheated body [26]. On the basis of a previous and accurate calibration (which considers the probe mounting and cables used on the analyses), CTA provides high-precision continuous velocity time series. In these analyses, a triaxial hot wire probe (DANTEC DYNAMICS 55P95) was used to measure velocity components on a three-axis reference system. The hot wire probe can acquire data at frequencies up to 400 kHz, with minimum and maximum speeds of 0.05 and 200 m/s, respectively.  
The probe was fitted to a DANTEC DYNAMICS probe support and attached to an ISEL one-axis positioning system (see Figure 12), which is remotely controlled with a location precision of 1 mm. The positioning system setup was explicitly manufactured for air amplifier analyzes, ensuring adequate positioning of the ISEL system at the different downstream positions of the wake.  
The Coanda nozzle gaps were manually adjusted to 0.23 mm, 0.15 mm, and 0.08 mm, following the gap apertures suggested by the manufacturer. This was achieved by using feeler gauges and careful manual adjustment of the screw. In these analyses, the expected uncertainty of the gap value, given by the gauge tolerances, was on the order of 0.01 mm.  
Varying the total pressure upstream from the pressure line, a compressed air pressure variation was analyzed, with an approximate range (varying between the different gap configurations) of the total pressure at the air amplifier inlet from \(p_{c}=0.2\) MPa to \(p_{c}=0.6\) MPa. Note that the upper limit of the pressure range differs from the numerical analyses, as it was limited by the facility constraints.
## 3 Results
### Microbiologic Outcomes  
RT-PCR showed the presence of FN, TD and TF in 75%, 100% and 92% of patients, respectively. AA was absent in all patients, PG was present in only one patient (8%) and PI was detected in 58% of patients, thus these bacteria were not included in the subsequent statistical analyses due to their low incidence value in the analysed samples. Kruskal-Wallis nonparametric statistics showed no differences between test, control and adjacent tooth in the abundance of FN (\(p\) = 0.67), TD (\(p\) = 0.62) and TF (\(p\) = 0.72) when analysed separately. The sum of all these bacteria were also not significantly different among test, control and adjacent tooth (\(p\) = 0.83).  
The presence of these bacteria (FN, TD and TF) was similar for the implants and for the tooth adjacent to the implants (Table 3). The only significant difference was in the test implants where the percentage of patients showing the presence of TD was higher than the presence of FN (\(\chi\)2 = 6.8, \(p\) = 0.01).  
These results evidenced that the implants did not show a different abundance of bacteria compared to the tooth and that the test and the control implants had no difference in bacterial colonization.  
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**FN**} & \multicolumn{2}{c}{**TD**} & \multicolumn{2}{c}{**TF**} \\ \hline  & **Test** & **Control** & **Tooth** & **Test** & **Control** & **Tooth** & **Test** & **Control** & **Tooth** \\ \hline abundance (mean \(\pm\) sd) & 6.1 \(\pm\) 13.9 & 76.1 \(\pm\) 256.3 & 1.3 \(\pm\) 1.7 & 77.2 \(\pm\) 265.4 & 10.5 \(\pm\) 34.5 & 2.5 \(\pm\) 7.7 & 9.4 \(\pm\) 26.3 & 8.9 \(\pm\) 24.6 & 1.8 \(\pm\) 5.4 \\ abundance (median) & 0 & 390 & 470 & 250 & 249 & 249 & 249 & 249 & 249 \\ presence (\% of patients) & 42 & 58 & 67 & 92 & 92 & 75 & 75 & 67 & 67 \\ \hline \hline \end{tabular}  
Abundance is expresses as (Geq)/mL \(\times\) 10\({}^{3}\). **FN**: _Fusobacterium nucleatum_; **TD**: _Traponema deticula_; **TF**: _Tammella fersythemensis_.  
\end{table}
Table 3: Subgingival microbiota from RT-PCR along test, control implants, and adjacent teeth.
## 3 Results  
### Cell Growth and Morphology of CDDP- and/or \(\beta\)-Cry-Treated hOMK and hOMF  
hOMK and hOMF were treated with CDDP at a concentration of 0.01 to 100 \(\mathrm{\SIUnitSymbolMicro\SIUnitSymbolMicro m}\) for 48 h, and hOMK and hOMF viability was then measured using the WST assay. Cell viability was markedly lower in cells treated with \(\geq\)5 \(\mathrm{\SIUnitSymbolMicro\SIUnitSymbolMicro m}\) CDDP than in control cells (Supplemental Figure S1). A previous study reported that the peripheral blood concentration of CDDP after a drip infusion was 0.73-3.04 \(\mathrm{\SIUnitSymbolMicro\SIUnitSymbolMicro m}\)/mL [25]. Therefore, in subsequent experiments, CDDP was used at a concentration of 1 \(\mathrm{\SIUnitSymbolMicro\SIUnitSymbolMicro m}\)/mL, and the experimental period was established as 7 days, during which oral mucositis may occur after the start of chemotherapy.  
CDDP enlarged the size of hOMK and hOMF with the accumulation of vacuoles in the cell plasma, while \(\beta\)-cry did not markedly affect their morphology (Figure 1A and Supplementary Figure S2).  
The numbers of hOMK and hOMF treated with 1 \(\mathrm{\SIUnitSymbolMicro\SIUnitSymbolMicro m}\)/mL CDDP for 7 days were significantly lower than the number of control cells (hOMK: 49.31% \(\pm\) 4.3, hOMF: 46.98% \(\pm\) 9.86) (Figure 1B). In contrast, the numbers of hOMK and hOMF treated with 100 nM \(\beta\)-cry for 7 days were significantly higher than those of control cells (hOMK: 127.34% \(\pm\) 12.98, hOMF: 115.85% \(\pm\) 8.87) (Figure 1B). Furthermore, the numbers of both cell types were slightly higher following the CDDP+\(\beta\)-cry treatment than after the CDDP treatment (hOMK: 59.60 \(\pm\) 10.75, hOMF: 52.26 \(\pm\) 2.6), although there was no significant increase.  
Effects of \(\beta\)-Cry on Inflammatory Cytokine and MMP mRNA Expression Levels in CDDP-Treated hOMK and hOMF  
In CDDP-treated hOMK and hOMF, significant increases were observed in the mRNA expression levels of IL-6 (OMK: 5.08 \(\pm\) 0.6-fold, OMF: 23.4 \(\pm\) 6.15-fold), IL-8 (\(2.75\pm 0.25\)-fold, OMF: 21.77 \(\pm\) 4.07-fold), and MMP-9 (1.88 \(\pm\) 0.63-fold, OMF: \(3.9\pm 1.1\)-fold) from those in control cells. However, no significant differences were observed in mRNA expression levels between \(\beta\)-cry-treated cells and control cells. In CDDP+\(\beta\)-cry-treated cells, significant reductions were observed in the mRNA expression levels of IL-6 (2.09 \(\pm\) 0.43-fold), IL-8 (1.61 \(\pm\) 0.52-fold), and MMP-9 (0.99 \(\pm\) 0.28-fold) in hOMK and those of IL-6 (14.49 \(\pm\) 2.78-fold) and MMP-9 (2.4 \(\pm\) 0.46-fold) in hOMF (Figure 2).  
Figure 1: Changes in morphologies and numbers of hOMK and hOMF after the CDDP treatment. (**A**) Morphologies of hOMK and hOMF in each group. Magnification \(\times 100\). (**B**) The numbers of CDDP-treated hOMK and hOMF were significantly lower than those of control cells, whereas those of \(\beta\)-cry-treated hOMK and hOMF were significantly higher. Values are means \(\pm\) S.D. \(n\) = 6 (sample number in each group) **\(p\)** \(<\) 0.01 vs. control.