esa-sceva/satcom-chunk-collection huggingface dataset:
# Superhydrophobic Polypyrrole-Coated Cigarette Filters for Effective Oil/Water Separation
## 3 Results and Discussion
### Oil Separation Ability  
Figure 6 shows the processes of oil/water separation for the original cigarette filter, Ppy-coated cigarette filter, and superhydrophobic Ppy-coated cigarette filter. For the original cigarette filter, when a mixture solution of petroleum ether (dyed with Sudan IV) and water (dyed with blue ink) was poured in the funnel, the cigarette filter firstly absorbed petroleum ether. The petroleum ether dripped into the measuring cylinder. When the water came into contact with the cigarette filter, the water, replacing the petroleum ether, started to drip into the measuring cylinder owing to the difference in density. Thus, the original cigarette filter failed to separate oil and water, as shown in Figure 6a. For the superhydrophobic Ppy-coated cigarette filter, when the mixture solution was poured in the funnel, the cigarette filter quickly absorbed petroleum ether, and the petroleum ether continuously dripped into the measuring cylinder. Owing to the water repellent, water could not penetrate into the pores of the modified cigarette filter. Thus, water and petroleum ether were separated efficiently by the modified cigarette filter, as shown in Figure 6b.  
Figure 5: Pyrrole content versus surface wettability.  
Figure 7a shows the efficiency of the modified cigarette filter for different oil/water separation cases. Both light and heavy oil could be separated by the modified cigarette filter. For light oil, the separation efficiency of the modified cigarette filter was 98.8% for an engine oil/water mixture. For heavy oil, like chloroform, the modified cigarette filter could separate greater than 98.5% by weight of water from the chloroform/water solution. Figure 7b shows the relationship between the separation efficiency and the number of cycles. Separation efficiency showed a downward trend. After 30 separation cycles of different oil/water mixture solutions, the separation efficiency for the petroleum ether/water mixture still reached 97.5%. Moreover, the separation efficiency reached 96.5%, 96.3%, and 97.3% for an engine oil/water mixture, vegetable oil/water mixture, and chloroform/water mixture, respectively, which revealed the good separation stability of superhydrophobic Ppy-coated cigarette filters for different separation cases of oil/water mixture solutions.  
Figure 6: Photos of oil/water separation: (**a**) ordinary sample; (**b**) superhydrophobic sample.  
Figure 7: Plots of separation efficiency and stability: (**a**) \(Q_{\text{se}}\) for different oils and organic solvents; (**b**) \(Q_{\text{se}}\) for different cycle numbers.
## Tracking Ecosystem Water Use Efficiency of Cropland by Exclusive Use of MODIS EVI Data  
**[PERSON] 1,2,*, [PERSON] 1,*, [PERSON] 3, [PERSON] 1, [PERSON] 4 and [PERSON] 5**  
1 Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; E-Mail: [EMAIL_ADDRESS]  
2 State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China  
3 Department of Soil, Water and Climate, University of Minnesota, St. Paul, [PERSON] 55108, USA; E-Mail: [EMAIL_ADDRESS]  
4 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; E-Mail: [EMAIL_ADDRESS]  
5 Key Laboratory of Poyang Lake Wetland and Watershed Research (Jiangxi Normal University), Ministry of Education, Nanchang 330022, China; E-Mail: [EMAIL_ADDRESS]  
* Authors to whom correspondence should be addressed; E-Mails: [EMAIL_ADDRESS] (X.T.); [EMAIL_ADDRESS] (H.L.); Tel.: +86-25-8688-2119 (X.T.); Fax: +86-25-8688-2119 (X.T.)[PERSON]  
Academic Editors: [PERSON], [PERSON] and [PERSON]  
_Received: 28 July 2015 / Accepted: 20 August 2015 / Published: 26 August 2015_  
evapotranspiration (ET), and the direct estimates by exclusive use of MODIS EVI data were evaluated using tower-based measurements. The results showed that ecosystem WUE were overpredicted at the beginning and ending of crop-growth periods and severely underestimated during the peak periods by the indirect estimates from MODIS products, which was mainly attributed to the error source from MODIS GPP. However, a simple empirical model that is solely based on MODIS EVI data performed rather well to capture the seasonal variations in WUE, especially for the growing periods of croplands. Independent validation at different sites indicates the method has potential for broad application.  
water use efficiency; cropland; MODIS; vegetation index; GPP; ET +
Footnote †: journal: Journal of Geoscience and Remote Sens.
# A Comparative Study of 3D UE Positioning in 5G New Radio with a Single Station
## 2 System Hypotheses and Signal Modeling
### Sounding Reference Signal in 5G NR  
In 5G NR, the SRS is transmitted by the UE for uplink channel sounding, which includes the channel estimation (in the frequency domain) and synchronization. As defined in 3 GPP TS 38.211 [16], an NR-SRS is an uplink orthogonal frequency division multiplexing (OFDM) signal filed with a Zadoff-Chu sequence on different subcarriers. For the purposes of communications, the SRS is used for closed-loop spatial multiplexing, uplink transmitting timing control, and reciprocity multi-user downlink precoding. To utilize the channel sounding function, the SRS must be known by both the UE (mobile transmitter) and gNB (base station receiver). With this prior knowledge known at the receiver, the SRS will be used to estimate the angle of the signal source and propagation delay by processing the received OFDM signal on an antenna array. In 5G NR, the SRS is transmitted as OFDM symbols, which are allocated in specified frequency (subcarrier) and time (slot) positions in 5G NR subframes. The generation of the SRS in 5G NR frames includes two steps: (i) Zadoff-Chu sequence \(\mathbf{r_{zc}}\in\mathbb{C}^{\mathbf{M}_{sc,b}^{rs}\times 1}\) generation (described in Section 2.2.1); (ii) mapping \(\mathbf{r_{zc}}\) to \(\mathbf{s_{sss}}\in\mathbb{C}^{\mathbf{W}\times 1}\) as an OFDM symbol (described in Section 2.2.2). Figure 2 shows a simplified example of SRS generation.
# Non-Destructive Testing Applications for Steel Bridges
## 3 NDT Methods with Potential Application to Steel Bridges
### Test Methods Applicable Only to External/Surface Defects
#### 3.1.2 Dye Penetrant Testing (PT)  
The Dye Penetrant Testing (PT) is an NDT method and is used to detect and monitor surface cracks, welded details, and gusset plate connections in steel bridge members. This method is inexpensive and simple, and can be implemented for the confirmation of the visual inspection. However, its process is time-consuming and, as a result, may not be cost-effective where multiple locations need to be inspected. The PT method relies on dye liquid that is applied onto the surface with the ability to penetrate a crack, void, and other surface defects in the element [10; 13; 14; 15]. The penetrant dye is usually packed in a kit that contains the required chemicals in three aerosol spray cans, i.e., a cleaner, a penetrant, and a developer. Each of the cans is related to a specific step of the process [4]. Figure 4 indicates the steps needed for the application of PT to provide the inspectors with accurate and valid results [13; 16; 17]  
Figure 3: Challenges of visual inspection method: (**a**) Lack of lighting [10]; (**b**) Visual inspection at heights can be dangerous and challenging [11].  
The dye penetrant method is highly sensitive, portable, and can detect even the smallest surface discontinuities. It can be applied to a variety of base material and is suitable for complex shapes. However, there are some disadvantages for this method: It is not suitable for inspecting the elements with a porous surface; it requires caution in pre-cleaning, chemical handling, and removal of the excess penetrant; and the inspector needs to access the tested components to safely conduct the whole inspection [17].
# Novel Numerical Analysis of a Self-Circulating Bearing
## 4 Conclusions  
The numerical model presented provides a framework for further study on self-circulating bearings. In applications where the additional space and risk of an external pumping system is not feasible, the self-circulating bearing has demonstrated the ability to support a variety of bearing loads with reasonable projected stability. The variation in permeability has a significant effect on the fluid circulation (injection velocity), bearing load capacity, and bearing stability. The range of bushing thickness studied here did not demonstrate significant effect on the bearing performance. The passive reservoir pressure was discussed as influencing the behavior of the bearing. The current model utilized a uniform roughness (represented through permeability) and homogeneous fluid but demonstrated the ability to be altered to study newer evolutions in porous journal bearings that may apply to the self-circulating bearing. The next evolutionary step recommended is improving the cavitation model and varying the passive reservoir representation. Future applications of this model would involve predicting bearing performance in various scenarios. This would also assist designers in deciding factors like the bushing thickness, reservoir depth, and recommended speed. Self-circulating bearings would be useful in applications where an external pumping system is not feasible, such as in exploratory vehicles.  
Conceptualization, E.J.C. and C.C.D.; Methodology, E.J.C. and C.C.D.; Software, E.J.C.; Validation, E.J.C.; Formal Analysis, E.J.C.; Investigation, E.J.C.; Resources, C.C.D.; Data Curation, E.J.C.; Writing--Original Draft Preparation, E.J.C.; Writing--Review and Editing, C.C.D.; Visualization, E.J.C. and C.C.D.; Supervision, C.C.D.; Project Administration, C.C.D. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
The authors would like to thank the late Dr. [PERSON] for his guidance in the development of the presented model.  
The authors declare no conflicts of interest.  
Figure 8: Effect of changing bushing thickness on bearing load capacity.
## 2 End-to-End QoS in WSNs
### Causes for Unreliability  
In wireless networks, packet errors are common due to fading caused by environment and interference from other wireless devices. WSNs are even more prone to errors as they may operate on hostile environments. Also, as nodes are often randomly deployed, the placing and the distances between nodes can be unideal, thus causing unreliable links.  
The synchronization via beacons has two major impacts on performance and reliability. First, missing a beacon prevents a node from participating in the following active period, therefore preventing a node forwarding its data. Second, several missed beacons indicate synchronization loss, which necessitates searching for neighbors with a time consuming network scan. For example, if a network uses 4 s access cycle and 10 channels, it takes 40 s to perform a complete network scan. During this time, a node cannot forward any data and generated packets must be buffered.  
Packet buffering in WSNs is limited due to the memory constraints. When a buffer is full, a packet must be dropped, which reduces reliability. Low power WSN platforms often depend on the data memory supplied by the MicroController Unit (MCU), as using external memories would increase cost and energy usage. The data memory range between 2 and 32 kB, where 4 kB is the most typical choice[10]. As part of the data memory must be reserved for processing the sensed data and maintaining route and neighbor information, the remaining buffer space is low.  
The amount of packets that fit to the buffer can be derived from the average packet size. As WSN traffic consists of sensor measurements or simple commands to actuators, a typical packet size is 32-64 B. For example, in IEEE 802.15.4 MAC maximum packet size is 128 B. Assuming 64 B packet size and 2 kB available buffer space, a buffer can hold 32 packets. As the packet must be buffered until it has been successfully routed, link errors combined with the burst nature of the WSN traffic increase buffer overflow probability significantly.
# An Efficient Scalable Scheduling MAC Protocol for Underwater Sensor Networks +
## 3 Challenges and Requirements
### Motivation  
Performance issues caused by long propagation delays, limited bandwidth, and energy consumption essentially result in the inefficiency of the handshake mechanism in acoustic channels. The handshaking process in underwater networks only allows for one data transmission in one control message, such as RTS/CTS, in the one-hop neighbourhood. If every node could be scheduled to transmit data at certain times with only one beacon window and one round window, the energy efficiency and throughput ratio would significantly improve. This is the basic driving idea of our proposed MAC protocol, in which spatial reuse (concurrent sending in different neighbourhoods) is introduced as a similar concept and has been developed based on acoustic channels for underwater networks.  
To further improve the MAC performance, we consider the underwater features such as three-dimensionality and depth of sensors in our proposed protocol, as will be explained in detail later. We also employ the time division to access the channel and make some improvements on network schedule for common TDMA. In this case, the time slot assignment method is used for improving the throughput, energy efficiency, and fairness by imposing less communication overhead in the scheduling process compared to those other TDMA approaches, which are impractical in UWSNs.
# Secure D2D Communication for 5G IoT Network Based on Lightweight Cryptography
## 2 Related Work
### Security Considerations for a 5G IoT Network  
In a 5G network, IoT applications correspond to mMTC and URLLC scenarios. For the security of D2D communication against threats, the D2D communication system has to provide security functions including authentication, data confidentiality/integrity and anonymity. However, IoT devices have limited resources in terms of performance, memory and power consumption. Therefore, the security functions must also provide efficiency, meaning that each security function has to be implemented lightly and run faster. The detailed description of security considerations are as follows:  
* Authentication. Authentication is a key requirement for securing D2D communication in the 5G IoT network. For most types of attacks, proper user authentication is the most basic and appropriate solution. Every network should be able to verify the identity of users in order to guarantee the security of the network.
* Data confidentiality and Integrity. The data transmitted in the IoT network contains sensitive information, and due to a variety of attacks that can eavesdrop on or modify that information, confidentiality and integrity are a big concern. For providing this, we have to encrypt the transmitted data and use hash functions or message authentication algorithms.  
* Anonymity. Anonymity refers to hiding the identity of origin and sensitive information such as location. Anonymity is a necessary security function to prevent attackers from targeting specific users for their purpose. In such cases, when anonymity is not provided, the attacker can choose a specific target for the attack. If you take the example of autonomous vehicles, the attacker may decide to attack a specific car. Therefore, anonymity should be considered extensively.
* Efficiency. Efficiency is the communication system's ability to be implemented and to operate economically. This consideration is about availability, which means that authorized users can access the information at any time they request it. This consideration is especially critical when it comes to the IoT network because IoT devices have limited resources.
## 3 Results
### Correlation Between Dietary Fibre Types and Measurements of Intestines and Organs  
Table 6 presents the relationship between individual variables calculated using a Spearman correlation. A moderate positive correlation (\(p\) < 0.05) was found between TDF and SDF (r = 0.64) in the chickens' diets, as well as between TDF in their diet and their gizzard weight (r = 0.69). A weak negative correlation was found between IDF fibre and SDF (r = \(-\)0.51) in the digestive tract of chickens and between IDF and proventriculars weight (r = \(-\)0.47). However, a weak positive correlation was found between IDF and the intestines, from the jejunum to the large intestine, inclusive, in the r range from 0.45 to 0.57. A \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline  & TDF & IDF & SDF & PW & GW & DL & JL & IL & CL & LL & HW & LW & \\ \hline TDF & & 0.09 & 0.44 & 0.25 & 0.0 & \(-\)0.06 & \(-\)0.01 & \(-\)0.23 & \(-\)0.20 & \(-\)0.13 & \(-\)0.17 & 0.17 & \\ \hline IDF & 0.09 & \(-\)0.51 & \(-\)0.47 & 0.16 & \(-\)0.24 & **0.51** & **0.57** & **0.46** & **0.45** & 0.27 & **0.36** & Correlation coefficient [+ / -] \\ \hline SDF & 0.44 & \(-\)0.51 & & 0.43 & 0.26 & 0.16 & \(-\)0.26 & **-0.56** & \(-\)0.23 & \(-\)0.51 & \(-\)0.37 & 0.07 & no & 0.00–0.35 \\ \hline PW & 0.25 & \(-\)0.47 & **0.43** & & 0.14 & 0.31 & \(-\)0.06 & \(-\)0.10 & \(-\)0.22 & \(-\)0.28 & \(-\)0.03 & 0.15 & weak & 0.36–0.57 \\ \hline GW & 0.16 & 0.16 & 0.26 & 0.14 & & \(-\)0.16 & 0.24 & 0.12 & \(-\)0.14 & 0.09 & 0.14 & 0.25 & medium & 0.58–0.80 \\ \hline DL & \(-\)0.06 & \(-\)0.24 & 0.16 & 0.31 & \(-\)0.16 & & \(-\)0.10 & \(-\)0.08 & 0.28 & \(-\)0.01 & \(-\)0.23 & 0.22 & & 0.81–1.00 \\ \hline JL & \(-\)0.01 & **0.51** & \(-\)0.26 & \(-\)0.06 & 0.24 & \(-\)0.10 & & 0.53 & **0.51** & **0.50** & 0.21 & 0.56 & & \\ \hline IL & \(-\)0.23 & 0.57 & \(-\)0.56 & \(-\)0.10 & 0.12 & \(-\)0.08 & 0.56 & & 0.52 & 0.47 & 0.49 & 0.52 & & \\ \hline CL & \(-\)0.20 & **0.46** & \(-\)0.23 & \(-\)0.22 & \(-\)0.14 & 0.28 & 0.51 & 0.52 & & 0.34 & 0.06 & 0.55 & & \\ \hline LL & \(-\)0.13 & 0.45 & \(-\)0.51 & \(-\)0.28 & 0.09 & \(-\)0.01 & 0.50 & 0.47 & 0.34 & & 0.24 & 0.10 & \\ \hline HW & \(-\)0.17 & 0.27 & \(-\)0.37 & \(-\)0.03 & 0.14 & \(-\)0.23 & 0.21 & 0.49 & 0.06 & 0.24 & & 0.35 & \\ \hline LW & **0.17** & **0.36** & **0.07** & **0.15** & **0.25** & **0.22** & **0.56** & **0.52** & **0.55** & **0.10** & **0.35** & & \\ \hline \end{tabular}
\end{table} 
Table 6: Heat map of Spearman correlation coefficients between kinds of dietary fibre, weight of individual organs, and measurements of the intestines. Abbreviations: IDF—total dietary fibre; IDF—insoluble dietary fibre; SDF—soluble dietary fibre; PW—proventriculars weight; GW—gizzard weight; DL—duodenum length; JL—jejunum length; IL—ieum length; CL—ccca length (average); LL—large intestine length; HW—heart weight; LW—liver weight.
## 3 Energy Consumption Tests
### Temperature Indicators
The impact of the indirect system on the working temperatures is summarized in Figure 7, which shows the average temperature difference between the air at the return port to the cabinet heat exchanger and the evaporating temperature (Equation (3)) and between the product and the evaporating temperature (Equation (4)):  
\[\Delta T_{air}=T_{air,return}-T_{O} \tag{3}\]  
\[\Delta T_{p}=\overline{T}_{p}-T_{O} \tag{4}\]  
The use of an indirect layout instead of a direct expansion system provokes an increment of these temperature differences. Taking as reference the maximum temperature difference driving the heat transfer processes (product minus return air temperatures), the increments are of 0.5 K at 23.3 \({}^{\circ}\)C, 0.6 K at 32.8 \({}^{\circ}\)C and 2.2 K at 43.6 \({}^{\circ}\)C for R-134a, and of 2.9 K at 23.3 \({}^{\circ}\)C, \(-\)0.2 K at 32.8 \({}^{\circ}\)C and 1.8 K at 43.6 \({}^{\circ}\)C for R-507A. Obviously, the increment of the temperature difference driving heat transfer processes when going to an indirect layout will influence the energy consumption of the system, which is detailed in the next subsection. Figure 6: Average cabinet temperatures during 24 h test.
## 2 Dataset and Methods
### In Situ Data
#### 2.2.2 Vegetation  
To characterize the vegetation cover for all reference fields, two types of measurements were performed during the airborne acquisitions: the leaf area index (LAI), and the vegetation height (VH).  
1. Leaf area index  
The leaf area index (LAI) is defined as the total one-sided area of green leaves per unit horizontal ground area. The LAI was estimated from the analysis of the directional canopy gap fraction measured from hemispherical digital photography. For each field, 12-25 hemispheric digital photographs were acquired at the same time as the flights. Mean LAI values observed for all reference fields ranged between 0 and 6.8 during the GLORI campaigns (Table 1). The value of zero corresponds to the wheat crops, which were senescent.  
2. Vegetation height  
The canopy height was measured over twenty or thirty plants for each reference field, twice at the Lamasquere site, and three times at the Marcheprime site. The mean value of the height was considered for each field, and it ranged between 0 and 257 cm during the GLORI campaigns (Table 1). The value of zero corresponded to the wheat fields.