esa-sceva/satcom-chunk-collection huggingface dataset:
## 6 Conclusions  
Legacy DCF coordinates the channel access among multiple nodes by employing a simple distributed control mechanism. However, with various multimedia applications being deployed, this pure distributed access control becomes hard to meet the requirements of these applications and it hinders the further improvement of throughput. In this paper, we present a decoupling DMAC algorithm by partitioning the channel access into contention period and data transmission period, which inherits the merit of distributed random channel access and enables nodes to perform a collision-free data transmission. We present the algorithm procedure and framing details and validate the effectiveness of this channel decoupling mechanism by numerical analysis. In addition, we also address the performance anomaly problem and propose the I-DMAC1 and I-DMAC2 algorithms applied to some multi-rate scenarios. By running some extensive simulations, these proposed algorithms are verified to significantly improve the system throughput and channel utilization. Inspired by these latest machine learning-based MAC algorithms in [29; 30], for our future work, we plan to take advantage of these machine learning-based mechanisms to optimize our proposed mechanism and integrate our proposed algorithm in 802.11 ax.  
Conceptualization, J.L.; data curation, Y.W.; formal analysis, J.L. and Y.W.; funding acquisition, J.L.; investigation, H.Y.; methodology, J.L. and H.Y.; project administration, J.L.; resources, Y.W.; software, H.Y.; supervision, J.L.; validation, H.Y.; visualization, Y.W.; writing, original draft, H.Y.; writing, review and editing, J.L., Y.W., and H.Y. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the National Science Foundation of China (61602073) and Chongqing Postgraduate Research and Innovation Project (CYS19260).  
We would like to appreciate the anonymous CSOC2019 reviewers for their constructive comments on an earlier version of this work.  
The authors declare no conflict of interest.
## 5 Results and Discussion
### SFDR Calculation  
For SFDR measurement, we consider \(\mathrm{R_{s}}\) and \(\mathrm{R_{LOAD}}\) to be 50 \(\Omega\), waveguide attenuation and \(\mathrm{P_{in}}\) to be 0.2 dB/cm and 25 mW, respectively, and \(\mathrm{R_{d}}\) as 0.85 A/W. \(V_{\pi}\) is taken from the calculations in the electrode design section. Laser relative intensity noise is 165 dB/Hz, according to the laser data sheet [29]. Operating temperature T is 290 K. Using these values, a noise floor of \(-\)179 dB is obtained at 1 Hz. RF output power in fundamental, IMD2 and IMD3 signals is calculated for \(v_{1}=v_{2}=1\) V with varied biasing voltage and plotted against the biasing angle in Figure 8a. The figure depicts at quadrature biasing that IMD2 is eliminated as suggested in Equation (4c). As the biasing angle increases towards 180\({}^{\circ}\), a decrease in IMD3 output power is also observed. To eliminate IMD3, the biasing point can be kept near 180\({}^{\circ}\) if the signals are wide apart so that IMD2 can be filtered out using a low-power RF filter. However, using the quadrature bias point, RF output of fundamental and IMD3 signals are plotted with NF for varying inputs of RF power in Figure 8b. Using Equation (5), SFDR3 is calculated and depicted in the figure as 121 dB/Hz\({}^{2/3}\).  
\begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Paper** & \(V_{\pi}L\) **(V.cm)** & **Electrooptic Bandwidth (GHz)** & **L (mm)** & \(V_{\pi}\) **(V)** \\ \hline
[12] (theo.) & 2.93 & \textless{}100 & 3 & 9.76 \\
[18] (exp.) & 2.2 & 100 & 5 & 4.74 \\
[19] (exp.) & 2.5 & 70 & 5 & 5.1 \\
[20] (exp.) & 6.7 & 106 & 5 & 13 \\
[21] (theo.) & 3.7 & 29 & 24 & 1.3 \\
[22] (exp.) & 1.75 & 40 & 5 & 3.5 \\
[23] (theo.) & 2.32 & 81 & 30 & 1.16 \\ This work & 1.74 & 136 & 2.9 & 6 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Performance comparison of various CPW-based TFLN modulators.
## 2 Theoretical Background
### The Weakest-Link Theory  
The weakest-link theory states that if the failure statistics of a structural system can be treated as a statistical chain of elements, then the structural reliability, denoted by \(R\), equals the product of each element's survival probability, i.e.,  
\[R=\prod_{i=1}^{N}R_{i} \tag{7}\]  
where \(R_{i}\) denotes the survival probability of element \(i\).  
Taking a logarithm of Equation (7) yields  
\[\ln R=\sum_{i=1}^{N}\ln R_{i} \tag{8}\]
# Effect of the Lubrication Parameters on the Ceramic Ball Bearing Vibration in Starved Conditions
###### Abstract  
The thickness of the oil film in ceramic ball bearings varies greatly at starved lubrication conditions, thus leading to non-uniform contact between the balls and raceways in the circumference. The lubrication parameters have a direct impact on the thickness of the oil film and then affect the dynamic characteristics of the ceramic ball bearings. A nonlinear dynamic model of ceramic ball bearing with limited lubrication is presented in this paper, and parametric studies on the effect of lubrication parameters are conducted. In starved conditions, the uneven contact between the ball and ring leads to changes in vibration, and the inner ring vibration is applied to evaluate the degree of starved lubrication. The results show that as the oil quantity increases, the bearing stiffness increases and results in increased peak frequency. As the oil quantity decreases, the thickness of the oil film reduces, resulting in the bearing vibration increase. The research findings provide a theoretical reference for ceramic ball bearing design and have guided significance for improving the service performance of ceramic ball bearings.  
Keywords:starved lubrication; ceramic ball bearing; bearing modeling; bearing vibration +
Footnote †: journal: Applied Sciences
###### Abstract  
The aim of this paper is to establish the cost-effectiveness of high-entropy alloy coatings, using the electrospray deposition technique, designed for a geothermal turbine blade's leading edge. The deposition of materials with high resistance to corrosion and erosion aims to increase the blade's service life, reduce maintenance costs and improve production efficiency. According to our previous research on the CoCrFeNiMo\({}_{\text{x}}\) high-entropy alloy system, the results showed a high corrosion resistance when in bulk or as a coating, and when tested in geothermal steam and in a saline solution. Based on the results, the high-entropy alloy was subjected to further analyses. The paper focused on two aspects of the research. The first direction was to explore the possibility of obtaining an effective, protective high-entropy alloy layer by the electrospray deposition method. To this end, various tests were performed to demonstrate that the new material possesses superior properties and is suitable for the geothermal environment's demands. The second direction was to calculate the economic efficiency of coating the areas intensely subjected to wear, based on reports published by the geothermal power plants' representatives. The final costs were compared with the commercially available equipment parts, and also with the general maintenance costs. From the calculation of the cost efficiency for the CoCrFeNiMo\({}_{0.85}\) high-entropy alloy, it resulted that the deposition method and the properties of the material are suitable for the operating conditions, representing an efficient and easy to apply solution to reduce maintenance costs in the geothermal industry.  
high-entropy alloy; corrosive media; economic efficiency; coatings; electrospray deposition Article
## 4 Experimental Test Results
### Young's Modulus  
Figure 7 shows the average [PERSON]'s modulus of concrete samples at 7 days and 28 days with the traditional mixture and the modified EMV mixtures.  
Figure 7 shows that all the other RCA mixes, regardless of having different mix designs, yielded 2-7% decreases in the [PERSON]'s modulus value at seven days. At 28 days, this gap is enlarged to range from 6-10%. Comparing the relative compressive strength drop of 11-20% in Figure 6b,c, the 6-10% decrease in the relative modulus of the modified EMV concrete mixes might be the result of the characteristic in the modified EMV method. It was explained by [PERSON] et al. [8] that modulus is proportional to the volume of total mortar; however, strength is mostly dependent on the strength of the mortar and the ITZ. [PERSON] et al. [42] reported equivalent modulus test results of RCA concretes with replacement levels of 30%, 50%, and 100% of RCAs. It was pointed out that the modulus of RCA is lower than that of NA and, consequently, due to the porous nature of RCA, the difference in the modulus of RCA and hardened cement paste will be smaller than that of NA and hardened cement paste.  
Meanwhile, the ERR mix, which contained high-quality RCA produced from PC concrete sleepers, resulted in only a 2% decrease in the elastic modulus value, compared to the control CNC mix. It is very clear that the strength decrease of concrete produced with RCA is due to the porous interface transition zone (ITZ) surface. Further studies are needed to enhance the strengthening of ITZs and their surroundings by using minerals such as silica fume, slag or ashes.
# Noether's Theorem in Non-Local Field Theories
## 1 Introduction  
According to [PERSON]'s theorem [1], the invariance of the Lagrangian function of a physical system with respect to continuous transformations leads to conservation laws and the corresponding existence of conserved charges. In its standard form, [PERSON]'s theorem refers to local field theories with derivatives, of no higher than second order, in the field equations.  
Quantum field theories with higher derivatives are used for intermediate regularization procedures (see, e.g., [2]). The low-energy regime of quantum chromodynamics (QCD) is known to be successfully described by chiral perturbation theory based on a power-series expansion in derivatives [3, 4]. Infinite higher-order derivatives, in the form of an infinite set of ordinary differential equations, appear in the treatment of the delay-time problem of the electromagnetic radiation-reaction [5, 6], which can be considered as an example of non-local theory. Field theories with higher-order derivatives or non-local theories are also discussed in the context of general relativity [7, 8]. In solid state physics, non-local field theories are successfully used to describe non-local interactions of atoms on scales up to the lattice parameter [9]. A conserved current associated with pairs of non-Noether or non-local symmetries is constructed in [10].  
The charge conjugation, parity, and time reversal (CPT) theorem states that the CPT symmetry violation can be related to non-local interactions. Low-energy nuclear and atomic experiments provide strict constraints on the scale of a possible violation of CPT symmetry. A simple classification of the effects of the violation of the C, P, and T symmetries and their combinations is presented by [PERSON] [11]. A class of inflationary models is based on a non-local field theory [12].  
In this paper, the question of whether one can generalize [PERSON]'s theorem to non-local field theory is discussed.  
As an initial step, we consider a Lagrangian that contains, along with a field \(\Psi=(\phi,\phi^{*})\), its higher derivatives \(\partial_{\mu_{1}}\dots\partial_{\mu_{n}}\Psi\), up to order \(n\geq 1\):  
\[\mathcal{L}=\mathcal{L}(\Psi,\partial_{\mu_{1}}\Psi,\dots,\partial_{\mu_{1}} \dots\partial_{\mu_{n}}\Psi). \tag{1}\]  
The Lagrangian given in (1) is still local as it is a function of the field and its finite-order derivatives are evaluated at a single point in space-time. To obtain a non-local field theory, one must include in (1) a dependence on an infinite number of field derivatives, i.e., by considering the limit \(n\to\infty\).  
In the remainder of this paper, we use a system of units such that \(\hbar=c=1\). Indices \(\mu,\ \
u,...\), denoted by Greek letters from the middle of the alphabet, run from 0 to 3. Indices \(\alpha,\ \beta,...\) denote the spatial components of tensors and run from 1 to 3. We use a time-like metric \(g_{\mu\
u}=\text{diag}(+1,-1,-1,-1)\), and indices enumerating members of internal-symmetry multiplets are suppressed.
## 3 Technological Platform for the Wireless Sensor Node  
The design of the agricultural platform system faced three significant challenges: building a sufficiently lightweight, energy efficient hardware capable of monitoring and control physical variables; incorporating and evaluating different operating systems and algorithms into a software to achieve autonomous transfer sensing and control variables; and integrating subsystems such as microprocessor, sensors and actuator modules and wireless networking into a fully functional wireless platform solution.
# Experimental Investigation of Oxygen Carrier Aided Combustion (OCAC) with Methane and PSA Off-Gas
## 3 Results
### Experiments with Methane
The difference between a system with flame combustion in the freeboard and a system with high in-bed fuel conversion is illustrated in Figure 7, where a comparison is made between the results in measured concentrations of NO and CH\({}_{4}\) for sand at 750 \({}^{\circ}\)C and for C28 at 900 \({}^{\circ}\)C.  
In Figure 8, it can be observed that, with sand at 750 \({}^{\circ}\)C, fuel conversion takes place mainly above the bed. This is obvious since the concentration of CH\({}_{4}\) is reduced significantly between MP4 and MP5. Between the same measurement points, the NO concentration increases significantly. This could be compared with the experiment with C28 at 900 \({}^{\circ}\)C, where CH\({}_{4}\) conversion takes place in the bed and almost no NO emissions are detected at any height in the reactor. The difference in the results between temperatures 750 and 900 \({}^{\circ}\)C can be further emphasized by observing Table 5 where the measured NO emissions are at least 79 ppm for all bed materials at MP8 at 750 \({}^{\circ}\)C, whereas no more than 11 ppm is detected at MP8 at 900 \({}^{\circ}\)C. This represents, therefore, a reduction in NO emissions by more than 93% compared to a case with flame combustion. It can be observed that the measured concentration of NO is higher with ilmenite as a bed material than with sand at 750 \({}^{\circ}\)C and 800 \({}^{\circ}\)C. A similar amount of methane conversion appears to take place above the bed in those cases, so the reason could instead be connected to the availability of oxygen in the bed. In the bed with an oxygen carrier, oxygen is available both in gaseous and solid phase in the form of the oxygen carrier material, which could contribute to a higher risk of NO formation. When C28 is used as a bed material, the measured NO concentration is lower, however, and this could be explained by the fact that more fuel conversion takes place in the bed with this bed material, which means that less fuel conversion can take place above the bed and cause local hotspots where NO may be formed. It should also be mentioned that NO may be reduced by reacting with the oxygen carrier to form N\({}_{2}\) (while the oxygen carrier is oxidized) but the reaction rate for this reaction may vary for different conditions.
# Engineering Method and Tool for the Complete Virtual Commissioning of Robotic Cells
## 3 Proposed Virtual Commissioning Approach
### Integrated Software Tools  
RS was chosen as the software tool to represent the virtual cell since it offers functionalities to model the geometrical layout, kinematic of devices, physical behavior, and control logic. RS originates as an offline programming software for ABB robots. Due to its virtual controller technology, RS can carry out extremely realistic simulations of the movements of the ABB robots and execute complex RAPID robot programs. Indeed, the software running on the real robot controllers (RobotWare) is the same as that utilized by the virtual robot controllers. Additionally, provides gives the possibility to model or import 3D geometries of other devices as well as to implement smart components (SCs). These are reusable blocks, including geometry, kinematics and functioning logics that can be utilized to realize the desired abstraction of real devices. Some basic SCs are provided by default in RS and can be combined to build more complex ones.  
In addition, ABB offers a developing tool to extend the basic functionalities of the software, namely the RS Software Development Kit (SDK). Due to the SDK, users can develop new applications by exploiting the Microsoft Visual Studio environment, such as add-ins or customized SCs, expanding software potentialities.  
On the other hand, TC is the software used for configuring and programming Beckhoff devices, including servo drives and PLCs. A PLC program can be written using several languages, such as ladder diagram, instruction list, function block diagram, structured text and sequential function chart (SFC). Such programs control the task execution flow of the entire cell, exchanging signals with the controls of the robots, motors, linear axes and other devices. The PLC runs on a hardware system that is capable of real-time performance, essentially a dedicated PC that ensures the cycles are executed in a timely manner.  
These two software have no native way of communicating with each other. However, in order to create a complete VC of a robotic cell, it is essential to emulate contributions of each controller (namely, PLC and robot controller) with specific simulation tools that must be coupled and synchronized. This is the reason for the implementation of a tool that allows data exchange between TC and RS.
## 3 Control Structure
### Power Control Module  
The power control module manages the active and reactive power exchange between the converter and the grid. It consists of two key components, an active power controller and a reactive power controller, both operating under a droop control strategy.  
The active power controller regulates the converter's synchronization with the grid by adjusting the reference angle \(\theta_{\mathrm{g}}\). This adjustment is driven by the difference between the measured active power \(p_{\mathrm{g}}\) and the reference value \(p_{\mathrm{g-ref}}\), which is typically set to zero to prioritize harmonic mitigation and reactive power support. The active power error, normalized by the system's base power \(S_{0}\), is processed through a droop coefficient \(D_{\mathrm{p}}\). This coefficient determines the frequency deviation from the nominal grid frequency \(\omega_{0}\) in response to power imbalances. The resulting frequency adjustment is integrated over  
Figure 3: Control block diagram of GFMC APF.  
Figure 2: Schematic diagram of GFMC APF.  
time to compute \(\theta_{\rm g}\), ensuring seamless synchronization with the grid. Mathematically, this relationship is expressed as  
\[\mathrm{d}\delta_{\rm g}/\mathrm{d}t=\omega_{0}D_{\rm p}(-p_{\rm g}/S_{0}) \tag{1}\]  
where \(\delta_{\rm g}\) represents the dynamic phase shift necessary to maintain grid stability during load variations.  
The reactive power controller manages voltage regulation by adjusting the \(d\)-axis reference voltage \(v_{\rm gfd\_ref}\). It operates on a similar droop principle, where the reactive power error is normalized by \(S_{0}\) and scaled by the droop coefficient \(D_{\rm q}\). This generates a per-unit voltage deviation \(\Delta v_{\rm gfd\_pu}\), which is converted to an actual voltage adjustment using the base voltage \(V_{0}\). The final \(d\)-axis reference voltage combines this deviation with the nominal grid voltage, allowing the converter to inject or absorb reactive power to support the voltage during grid disturbances such as sags or swells. The control equation for the \(d\)-axis reference voltage is given by  
\[v_{\rm gfd\_ref}=V_{0}D_{\rm q}(q_{\rm g\_ref}/S_{0}-q_{\rm g}/S_{0})+v_{\rm gfd \_ref} \tag{2}\]  
highlighting how the controller dynamically balances reactive power exchange while maintaining voltage stability.
# Changes of Gait Patterns after Correction of Refractive Error in the Elderly with Cataracts
## 2 Materials and Methods
### Evaluation of Gait Patterns  
The measurement of changes in gait patterns before and after the correction of refractive errors was performed using the Optogair gait analysis system (Optogair, Microgate, Bolzano, Italy). Optogair consists of two transmission and reception bars, each 1 m long, with light-emitting diodes installed at 1-cm intervals on one bar. Two bars are installed facing each other, enabling extension up to 100 m [19]. The analysis of various gait patterns can be performed using continuous infrared communication sent from the transmission bar to the reception bar. This system can be used for the evaluation of both natural walking and walking on a treadmill. The analysis of the factors affecting gait patterns included step length (cm), stride length (cm), and stride width (cm), as well as cadence (steps/min) and walking velocity (s/m), as shown in Figure 1. Step length indicates the distance by which the foot can move forward during each swing. Stride length is the distance between two successive placements of the same foot, and it consists of two step lengths--left and right--each of which is the distance by which the named foot moves forward in front of the other one. Step width indicates the side-to-side distance between the lines of the two feet, measured usually at the midpoint of the backs of the heels but sometimes below the centers of the ankle joints. Finally, cadence is the number of steps taken in a given time, with the usual unit being steps per minute, and walking velocity is the distance covered by the whole body in a given time [20].
## 2 Case Presentation
### Design and Manufacturing of the Custom Matrices
#### 2.1.2 Additive Manufacturing  
The completed model of the matrix was saved in STL format and sent to the dental laboratory (AB DENT DESIGN, Domaszek, Hungary), where it was fabricated with an SLS 3D printer (MYSINT, 300 SISMA, Vicenza, Italy) using a cobalt-based metal powder (Mediloy S-Co, BEGO, Bremen, Germany). During SLS manufacturing a high-power laser selectively sinters the powdered metal particles together, layer by layer, to create the three-dimensional object (Figure 3).  
Figure 2: The custom matrix was designed and modeled on the surface of the digital impression in all three cases ((**A–C**), respectively).  
During the manufacturing process, the density of the material is close to 100%, resulting in the highest tensile strength value. After manufacturing, the surface of the matrix remains rough, which must be polished or sandblasted afterward. To simultaneously maintain structural rigidity and flexibility, the surface of the device was only smoothed on the inside, but only to an extent that did not affect the accuracy (Figure 4).  
Figure 3: (**A**) the 3D model of the individualized matrix in the STL model; (**B**) the models are loaded in the SLS manufacturing software; (**C**) A high-power laser selectively sinters the powdered metal particles together, layer by layer, to create the three-dimensional object.  
Figure 4: Individualized matrices after fabrication for all three cases ((**A**–**C**), respectively). After manufacturing, the surface of the object remains rough. The surface of the inside was smoothed but only to an extent that did not affect the accuracy.