esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Improvements in PRI Implementation
### Instruments  
Various instruments have been used for obtaining PRI in addition to the traditional ground-based spectroradiometer. A PRI imaging system was developed using a low-cost CCD camera and band-pass filters (530 and 570 nm) to non-destructively evaluate micropropagated plantlets, and has been successfully tested in cultured plantlets and from outside the culture vessels [89; 140]. An automated multi-angular spectroradiometer (AMSPEC I and II system) [4] was designed and CHRIS/PROBA was used [71; 90; 154; 151] for instantaneously measuring the spectra of a canopy at multiple detection angles along the tracking path, and for illustrating the effect of canopy structure and detection geometry at various spatial scales. CHRIS/PROBA, however, can only provide a very limited spatial coverage, which inhibits the monitoring of multiple-angular PRI at regional and global scales [154]. A temperature-controlled spectrometric system was also designed to collect high resolution spectral data to detect the diurnal and seasonal variation of RUE and fluorescence [137]. Other instruments, such as a simple filtered photodiode (QuadPod) [155], a low-cost spectroscopic instrumentation (PRiAnalyze) [130] and an automated PRI sensor with upward- and downward-facing sensors [76], were developed to explore the environmental and physiological constraints on photosynthesis and to improve remote-sensing studies of carbon uptake.
## 5 Experimental Setup and Results
### Experiment 3--Processing Hand Gestures Image Quality  
In this section, the experiment is carried out by changing the quality of the hand gesture image and then processed through the proposed system. Figure 13 shows the four variants of a letter from the PSL dataset. All the images are correctly detected, thus confirming that the proposed system is able to detect the correct gesture for varying image quality. In this experiment, the image quality of the acquired hand gestures varies, and the results show that the system is able to detect the letters correctly. This is an important result since the acquired image quality can vary due to background color, sharpness, background texture, etc.
###### Abstract  
Metal nanoparticles (NPs) made of gold, silver, and platinum have been synthesized by means of pulsed laser ablation in liquid aqueous solution. Independently from the metal nature, all NPs have an average diameter of \(10\pm 5\) nm. The \(\zeta\)-potential values are: \(-62\pm 7\) mV for gold, \(-44\pm 2\) mV for silver and \(-58\pm 3\) for platinum. XPS analysis demonstrates the absence of metal oxides in the case of gold and silver NPs. In the case of platinum NPs, 22% of the particle surface is ascribed to platinum oxidized species. This points to a marginal role of the metal oxides in building the negative charge that stabilizes these colloidal suspensions. The investigation of the colloidal stability of gold NPs in the presence of metal cations shows these NPs can be destabilized by trace amounts of selected metal ions. The case of Ag\({}^{+}\) is paradigmatic since it is able to reduce the NP \(\zeta\)-potential and to induce coagulation at concentrations as low as 3 uM, while in the case of K\({}^{+}\) the critical coagulation concentration is around 8 mM. It is proposed that such a huge difference in destabilization power between monovalent cations can be accounted for by the difference in the reduction potential.  
metal nanoparticles; laser ablation; zeta-potential; XPS +
Footnote †: journal: Applied Physics Letters B
## 1 Introduction  
Transient absorption spectroscopy is a well-known technique for studying quantum dynamics on the femtosecond time scale [1; 2]. When applying an external electromagnetic field, it is possible to modify the absorption cross-section of an XUV or X-ray probe pulse. This allows observing the dynamics driven in the system by the field. Time-resolved spectroscopy is applied today to all states of matter, including the gas, liquid, solid, and plasma phases, as well as large biomolecules [3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15].  
As a function of the intensity of the applied external electromagnetic field different processes can be studied. In the case of optical tunnel ionization, probing after the strong-field pump pulse provides spectroscopic information about the residual ion, such as ion quantum state distributions [16; 17] and orbital alignment [18; 19]. At lower field strengths, laser-dressing and molecular alignment effects may be investigated [20; 21; 22; 23; 24; 25; 26; 27; 28].  
In the past, measurements were typically performed in the infrared, visible, and ultraviolet spectral regions, using femtosecond or longer laser pulses [29; 30]. Transient absorption spectroscopy was also performed with soft and hard X-rays down to time scales of picoseconds [31; 32]. About ten years ago, soft X-ray transient absorption was demonstrated for femtosecond resolved probing in the gas phase [17] and condensed phase [33] by using high-order harmonics.  
The advent of attosecond light pulses [34; 35; 36; 37; 38] has opened up the possibility of studying fundamental questions related to the quantum dynamics of electrons on their natural time scale. Particularly, attosecond transient absorption (ATA) spectroscopy [39] gives access to ultrafast dynamics of bound and autoionizing electronic states in rare gas atoms, molecules, and solids. If the attosecond pulse is used to initiate the electronic dynamics, it coherently populates bright (dipole allowed) states, forming a wave packet. The coherence between the initial (ground) state and each excited state gives rise to a nonstationary polarization. The presence of another electromagnetic field--a dressing field--affects the absorption of the attosecond pulse and, thus, provides control of the electronic wave packet created. Various dynamical aspects of the launched wave packet are imprinted in the delay-dependent absorption spectra.  
A theoretical analysis of the ATA signal is crucial for understanding and maximizing its information content [40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50]. The goal of the current work is to provide an elementary explanation of the signals one can obtain in ATA experiments. We perform a perturbative analysis of the transient absorption signal as a function of the time delay between the attosecond excitation pulse and the femtosecond dressing pulse. Furthermore, through numerical calculations for a model atom, we illustrate how the ATA signal reveals the real-time attosecond dynamics of the system.
###### Abstract  
With the development of spectrum observation technology, solar-induced chlorophyll fluorescence (SIF)--an effective substitute for photosynthesis--has been widely used to monitor crop stress, vegetation phenology and ecosystem productivity. The relationship between fluorescence and photosynthesis is complicated because they are sensitive to environmental changes. Understanding the response of SIF to environmental factors is of great significance for clarifying the variation dynamic and relationship between SIF and photosynthesis under different conditions. In this study, the canopy SIF and the environmental factors of a _Quercus variabilis_ BI. plantation were observed simultaneously, and the response of SIF to environmental factors at a daily scale and at a half-hour scale was analyzed. The results showed that SIF had obvious seasonal and diurnal dynamics and was mainly driven by photosynthetically active radiation (PAR). The influence of PAR, air temperature (Ta), vapor pressure deficit (VPD), soil moisture (SM) and wind speed (Ws) on SIF varied with the lapse of the growing season. After eliminating the covariant effect of PAR on the Ta and VPD during the whole growing season, the relationship between VPD and SIF was found to be negative, and the effect of Ta on SIF disappeared. This study enriched the ground observation dataset and provided support for understanding the variations in the relationship between SIF and photosynthesis under different conditions.  
SIF; temporal dynamic; tower-based observation; _Quercus variabilis_ BI. plantation; environmental factors +
Footnote †: journal: remote sensing  
0000-0001-9993-3331][PERSON]  
1 Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; [PERSON]ADDRESS] (M.H.); [EMAIL_ADDRESS] (X.C.); [EMAIL_ADDRESS] (H.H.); [EMAIL_ADDRESS] (Y.Z.); [EMAIL_ADDRESS] (X.W.); [EMAIL_ADDRESS] (Q.P.); [EMAIL_ADDRESS] (C.G.)
###### Abstract  
The performance prediction of an optical communications link over maritime environments has been extensively researched over the last two decades. The various atmospheric phenomena and turbulence effects have been thoroughly explored, and long-term measurements have allowed for the construction of simple empirical models. The aim of this work is to demonstrate the prediction accuracy of various machine learning (ML) algorithms for a free-space optical communication (FSO) link performance, with respect to real time, non-linear atmospheric conditions. A large data set of received signal strength indicators (RSSI) for a laser communications link has been collected and analyzed against seven local atmospheric parameters (i.e., wind speed, pressure, temperature, humidity, dew point, solar flux and air-sea temperature difference). The k-nearest-neighbors (KNN), tree-based methods-decision trees, random forest and gradient boosting- and artificial neural networks (ANN) have been employed and compared among each other using the root mean square error (RMSE) and the coefficient of determination (R\({}^{2}\)) of each model as the primary performance indices. The regression analysis revealed an excellent fit for all ML models, indicative of their ability to offer a significant improvement in FSO performance modeling as compared to traditional regression models. The best-performing R\({}^{2}\) model found to be the ANN approach (0.94867), while random forests achieved the most optimal RMSE result (7.37).  
free space optical communication; received signal strength indicator; atmospheric turbulence; refractive index structure parameter; machine learning +
Footnote †: journal: 10 June 2021
###### Abstract  
Automated classification of satellite images is a challenging task that enables the use of remote sensing data for environmental modeling of Earth's landscapes. In this document, we implement a GRASS GIS-based framework for discriminating land cover types to identify changes in the endorheic basins of the ephemeral salt lakes Chott Melrhir and Chott Merouane, Algeria; we employ embedded algorithms for image processing. This study presents a dataset of the nine Landsat 8-9 OLI/TIRS satellite images obtained from the USGS for a 9-year period, from 2014 to 2022. The images were analyzed to detect changes in water levels in ephemeral lakes that experience temporal fluctuations; these lakes are dry most of the time and are fed with water during rainy periods. The unsupervised classification of images was performed using GRASS GIS algorithms through several modules: \"i.cluster\" was used to generate image classes; \"i.maxlik\" was used for classification using the maximal likelihood discriminant analysis, and auxiliary modules, such as \"i.group\", \"r.support\", \"r.import\", etc., were used. This document includes technical descriptions of the scripts used for image processing with detailed comments on the functionalities of the GRASS GIS modules. The results include the identified variations in the ephemeral salt lakes within the Algerian part of the Sahara over a 9-year period (2014-2022), using a time series of Landsat OLI/TIRS multispectral images that were classified using GRASS GIS. The main strengths of the GRASS GIS framework are the high speed, accuracy, and effectiveness of the programming codes for image processing in environmental monitoring. The presented GitHub repository, which contains scripts used for the satellite image analysis, serves as a reference for the interpretation of remote sensing data for the environmental monitoring of arid and semi-arid areas of Africa.  
[PERSON], [PERSON] GRASS GIS Scripting Framework for Monitoring Changes in the Ephemeral Salt Lakes of Chotts Melrhir and Merouane, Algeria.  
10 May 2023  
28 May 2023  
20 June 2023  
2023 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/by/](https://creativecommons.org/licenses/by/)]([https://creativecommons.org/licenses/by/](https://creativecommons.org/licenses/by/)) 4.0/).  
Sahara Desert; Africa; salt lake; cartography; image analysis; satellite image; remote sensing; geography; GRASS GIS; mapping
## 3 Data Used in This Study
### Data Setup  
**Dataset**. In this experiment, three datasets from three buildings in different regions are employed to evaluate the models, i.e., Hawthorn Campus--ATC Building (denoted as _DatasetS1_), Hawthorn Campus--AMDC Building (denoted as _DatasetS2_), and Wantrina Campus--KIOSC Building (denoted as _DatasetS3_). The two datasets _DatasetS1_ and _DatasetS2_ contain the energy consumption from 2017 to 2019, and the dataset _DatasetS3_ contains the energy consumption from 2018 to 2019. The prediction value is the difference between the previous and the intermediate next time in using energy, or the cumulation of energy. The historical value is 96 data points every 15 min to predict the next value.  
**Configuration of the proposed model**. The proposed model, M-LSTM, consists of a succession of one input layer, two LSTM layers, and one dense layer at the end. The input  
Figure 4: Average electricity accumulation in every 1 h at Hawthorn Campus—ATC Building in 2018. As can be seen, electricity consumption peaks between 8 a.m. and 21 p.m.  
Figure 3: Electricity accumulation in every 15 min at Hawthorn Campus—ATC Building.  
Figure 2: Location of Hawthorn Campus and Wantrina Campus in Metropolitan Melbourne, Victoria, Australia.  
layer contains two input types, as described in Section 4.1. In the following, the first LSTM layer wraps eight LSTM units, and the second wraps four units. The last dense layer has one unit for predicting energy consumption.  
**Configuration of bench-marking models**. As mentioned earlier, three competitive models are used for comparison: LSTM, Bi-LSTM, LR, and SVM models. The LSTM model consists of one single layer with one unit, followed by a Dense layer for prediction. The Bi-LSTM consists of one single Bi-Directional LSTM layer of one unit, followed by a Dense layer for prediction as the LSTM model. The LR model trains on one dense layer.  
**Training Configuration**. Both M-LSTM, LSTM, Bi-LSTM, LR, and SVM models are trained using the same training set and evaluated on the same test set. In _DatasetS1_ and _DatasetS2_, the models are trained on the data from 2017 and 2018. In _DatasetS3_, the models are trained on the data from 2018 to demonstrate the ability of models with a lack of training data.
# Spatiotemporal Assessment and Correction of Gridded Precipitation Products in North Western Morocco
## 3 Results and Discussion
### Evaluation Based on Pixel Average  
As part of this study, an evaluation was conducted using the average of rain gauge stations and the average of their pixels for all precipitation products. The GPM-F model best describes the seasonal cycle among the four products (Figure 18a). The GPM-F model showed superior performance compared to other products most likely due to advancements in calibration techniques and validation methodologies that help refine the accuracy of satellite precipitation products. GPM final benefits from these advancements, which may involve more accurate radiometric calibration, better accounting for sensor biases, and  
Figure 17: Ability of precipitation products to describe the average daily precipitation of the summer months for each station.  
enhanced validation against ground-based observations [7; 8; 39]. In terms of magnitude, ERA5 overestimates precipitation excessively compared to other products, resulting in high amplitude (Figure 18a). Furthermore, it is visible that the GPM-L and GPM-E models underestimate precipitation for the months of January to April, which is consistent with the regression metric results for rainy months (Figure 14).  
Since the beginning of the study, the GPM-F model has shown the lowest bias for all temporal scales, followed by GPM-L, GPM-E, and ERA5. The RMSE and MAE are also lowest with the GPM-F model, followed by GPM-E, GPM-L, and ERA5. In terms of consistency, ERA5 remains the most correlated product with ground data, followed by GPM-F, GPM-L, and GPM-E (Figure 19).  
The ability of precipitation products to describe daily average precipitation remains generally unsatisfactory, but the GPM-F performs better than the other products (Figure 20). In terms of frequency, the GPM products are able to reflect the frequencies of each class. However, ERA5 tends to underestimate the frequencies of the class (\(0\leq\text{T}<1\)), which represents the majority of precipitation in the study area, and overestimate the frequencies of other classes (Figures 21 and 18b).  
Figure 19: Pixel mean regression metric bar plots for all precipitation products.  
Figure 18: (**a**) Ability of each product to describe precipitation cycles for the pixel average. (**b**) Frequencies of the different intensity categories of each precipitation product for the pixel average.
###### Abstract
proposed a modified modeling method [32] in which the steel beam and concrete slab were separately modeled by beam elements and the non-linear spring elements were added between them to model the slip effect. This method was verified to be effective but needed a fussy modeling process to define the DOFs coupling relation. [PERSON] [33; 34; 35] and [PERSON] et al. [36] proposed the idea of introducing additional DOFs into the Euler-Bernoulli beam element to consider interfacial slip effects. A three-node 10-DOF element, taking the axial deformation of steel beams and concrete slabs as the separate DOFs, was proposed for the composite beam with deformable connectors. This was a good idea and was followed by the authors. While a new thought of taking the interfacial relative slip deformation as the additional DOF was proposed in this paper, then the FE formulation was further simplified and a two-node 8 DOF element was built. (2) For the modeling of the external tendon, ignoring frictions between tendon and deviators, the traction was assumed to be equal along the whole length. With the strain-compatible relation considered, [PERSON] et al. [28; 29; 30] proposed an equivalent loads method to model the unbonded effects of the external tendon. They only derived the resistance force equations but ignored the stiffness constructions of external tendons, reducing the numerical convergence in the Newton solution. Taking the external tendon as a whole member, the complete resistance vector and stiffness matrix of a multi-node slipping cable element are further derived and directly presented herein. In this paper, a new beam-tendon model is proposed for the flexural analysis of EPCBs with deformable interfacial connectors. A two-node 8-DOF fiber beam element is proposed for steel-concrete composite beams with material, geometric and interfacial connection nonlinearity. A multi-node slipping cable element is constructed to model the unbonded phenomenon of external tendons with the complete resistance vector and stiffness matrix. Compared with the existing method, this paper provides more simplified and highly efficient FE formulations which were then successfully developed in the open-source framework OpenSees. The proposed model and developed procedure are fully verified against the experimental results of simply supported and continuous EPCBs. The verified model is used for the parametric analysis. The effects of various factors, including deviator spacing, the effective height of external tendon, interfacial slip and loading types are then discussed.
# Research on a Rail Defect Location Method Based on a Single Mode Extraction Algorithm
## 2 An Accurate Modal Identification Method
### Modal Identification  
In Figure 4, T is the transmitter of the guided waves, R is the receiver of guided waves, X is the location of a rail defect, and the arrows show the propagation paths of the guided waves. Path 1 is the direction of backward propagation after exciting the guided wave. Paths 2 and 3 are the directions of transmission and reflection after the guided wave meets the crack. According to the propagation time of the reflected wave (Path 3) and the group velocity of the main modes, the guided wave propagating distance of Path 3 can be calculated to locate the defect.  
To solve the problem of defect location, it is very important to analyze the mode propagation and reflection of guided waves in defective rails. The amplitude of each mode in a complete rail can be calculated using the excitation response algorithm, as described in Section 2.2, but the mechanisms involved in the interaction between modes and defects are still difficult to understand. Therefore, a method that can accurately analyze the direct mode and reflection mode of a defect is needed. In fact, the accurate modal identification method used in this paper is the inverse transformation of the excitation response analysis method.
# Metal Release and Cell Viability of 316L Stainless Steel Sputter-Coated with N-Doped a-C:H Coatings
## 4 Conclusions  
In this study, hydrogenated amorphous carbon coatings were successfully modified by nitrogen addition, via reactive magnetron sputtering. Two N doping contents of 6 and 9 at.% were attained.  
These low doping levels (<10 at.%) should be an improvement of the coated 316L stainless steel corrosion behavior. Indeed, no microstructural changes, detachments and/or cracking of the coatings were observed upon the 30-day acidic immersion test. The most effective protecting behavior of the SS alloys was found for the undoped CH_0N film, according to the lowest metal release rates obtained.  
The cell viability test results showed that all coated samples were biocompatible, since their medians exceeded the 70% level regarding the control. The good biocompatibility of the medical grade 316L SS was further enhanced upon surface modification via carbon materials deposition, with or without N addition.  
These findings reinforce the need for simultaneously assessing both the physiochemical and biological properties of materials intended to be used in the medical field.  
Conceptualization, C.S.L. and A.C.S.; methodology, C.S.L. and A.C.S.; software, A.F. and J.R.M.; validation, C.S.L. and A.C.S.; formal analysis, A.F., J.R.M., M.P., K.L., C.S.L. and A.C.S.; investigation, A.F., J.R.M., L.S., M.P. and A.C.S.; resources, C.S.L. and A.C.S.; data curation, A.F. and J.R.M.; writing--original draft preparation, A.F.; writing--review and editing, C.S.L. and A.C.S.; visualization, A.F.; supervision, C.S.L. and A.C.S.; project administration, C.S.L. and A.C.S.; funding acquisition, C.S.L. and A.C.S. All authors have read and agreed to the published version of the manuscript.  
This research was sponsored by national funds through FCT--_Fundazio para a Ciencia e a Tecnologia_, under the project UIDB/00285/2020 and LA/P/0112/2020, and through the PhD grant SFRH/BD/143905/2019 attributed [PERSON]; and under the projects CENTRO-01-0247-FEDER-017823, SII&DT 17823 EASYPET, POCI-01-0145-FEDER-016855, PTDC/BBB-IMG/4909/2014, CENTRO-01-0247-FEDER-039880, and PTDC/EMEMD/2140/2020.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding authors.  
The authors are truly grateful to [PERSON], from the NOVA University Lisbon, for kindly providing access to the optical tensiometer for contact angle measurements. The authors also acknowledge [PERSON], from CEMMPRE, for performing the AFM measurements.  
The authors declare no conflicts of interest.