bluuebunny/crossref_metadata_2025 huggingface dataset:
Increase the Surface PANI Occupancy of Electrospun PMMA/PANI Fibers: Effect of the Electrospinning Parameters on Surface Segregation
Authors: Qu Chen , Zhao Peng , Ren Yifan , Wu Chuandong , Liu Jiemin
Published: August 2022

For preparing high-performance electrospun fibers with functional molecules that cannot cross-entangle themselves, such as conductive polymers, promoting the aggregation of functional molecules on the surface by surface segregation is a promising approach. In the present study, electrospun polymethyl methacrylate/polyaniline (PMMA/PANI) fibers were prepared under various conditions, including solution composition, applied voltage, tip-to-collector distance, temperature, humidity, and gas-phase solvent concentration, to examine the effects of the parameters on fiber morphology and surface segregation. The changes in fiber morphology and variations in the intensity of PANI and PMMA’s characteristic bands were investigated with scanning electron microscopy (SEM) and Raman spectroscopy. The results demonstrated that by changing the saturation difference and the viscosity, the amount of PMMA and PANI added significantly influenced whether surface segregation could occur. The effect of other investigated parameters on surface segregation was concluded to alter the molecular migratable time by affecting the jet flight time and the solvent volatilization rate. Among them, increasing the solvent concentration could significantly promote surface segregation without sacrificing morphological advantages. When the solvent concentration increased from 1.4 to 158 mg/m3, the Raman peak intensity ratio of PANI and PMMA increased from 2.91 to 5.05, while the fiber diameter remained essentially constant.
Pilot-Scale Processing and Functional Properties of Antifungal EVOH-Based Films Containing Methyl Anthranilate Intended for Food Packaging Applications
Authors: Aragón-Gutiérrez Alejandro , Heras-Mozos Raquel , Montesinos Antonio , Gallur Miriam , López Daniel , Gavara Rafael , Hernández-Muñoz Pilar
Published: August 2022

Antimicrobial packaging has emerged as an efficient technology to improve the stability of food products. In this study, new formulations based on ethylene vinyl alcohol (EVOH) copolymer were developed by incorporating the volatile methyl anthranilate (MA) at different concentrations as antifungal compound to obtain active films for food packaging. To this end, a twin-screw extruder with a specifically designed screw configuration was employed to produce films at pilot scale. The quantification analyses of MA in the films showed a high retention capacity. Then, the morphological, optical, thermal, mechanical and water vapour barrier performance, as well as the antifungal activity in vitro of the active films, were evaluated. The presence of MA did not affect the transparency or the thermal stability of EVOH-based films, but decreased the glass transition temperature of the copolymer, indicating a plasticizing effect, which was confirmed by an increase in the elongation at break values of the films. Because of the additive-induced plasticization over EVOH, the water vapour permeability slightly increased at 33% and 75% relative humidity values. Finally, the evaluation of the antifungal activity in vitro of the active films containing methyl anthranilate showed a great effectiveness against P. expansum and B. cinerea, demonstrating the potential applicability of the developed films for active food packaging.
Chitosan–Hyaluronic Acid Nanoparticles for Active Targeting in Cancer Therapy
Authors: Puluhulawa Lisa Efriani , Joni I Made , Elamin Khaled M. , Mohammed Ahmed Fouad Abdelwahab , Muchtaridi Muchtaridi , Wathoni Nasrul
Published: August 2022

Cancer is the most common cause of death worldwide; therefore, there is a need to discover novel treatment modalities to combat it. One of the cancer treatments is nanoparticle technology. Currently, nanoparticles have been modified to have desirable pharmacological effects by using chemical ligands that bind with their specific receptors on the surface of malignant cells. Chemical grafting of chitosan nanoparticles with hyaluronic acid as a targeted ligand can become an attractive alternative for active targeting. Hence, these nanoparticles can control drug release with pH- responsive stimuli, and high selectivity of hyaluronic acid to CD44 receptors makes these nanoparticles accumulate more inside cells that overexpress these receptors (cancer cells). In this context, we discuss the benefits and recent findings of developing and utilizing chitosan–hyaluronic acid nanoparticles against distinct forms of cancer malignancy. From here we know that chitosan–hyaluronic acid nanoparticles (CHA-Np) can produce a nanoparticle system with good characteristics, effectiveness, and a good active targeting on various types of cancer cells. Therefore, this system is a good candidate for targeted drug delivery for cancer therapy, anticipating that CHA-Np could be further developed for various cancer therapy applications.
The Cell-Wall β-d-Glucan in Leaves of Oat (Avena sativa L.) Affected by Fungal Pathogen Blumeria graminis f. sp. avenae
Authors: Gregusová Veronika , Kaňuková Šarlota , Hudcovicová Martina , Bojnanská Katarína , Ondreičková Katarína , Piršelová Beáta , Mészáros Patrik , Lengyelová Libuša , Galuščáková Ľudmila , Kubová Veronika , Matušíková Ildikó , Mihálik Daniel , Kraic Ján , Havrlentová Michaela
Published: August 2022

In addition to the structural and storage functions of the (1,3; 1,4)-β-d-glucans (β-d-glucan), the possible protective role of this polymer under biotic stresses is still debated. The aim of this study was to contribute to this hypothesis by analyzing the β-d-glucans content, expression of related cellulose synthase-like (Csl) Cs1F6, CslF9, CslF3 genes, content of chlorophylls, and β-1,3-glucanase content in oat (Avena sativa L.) leaves infected with the commonly occurring oat fungal pathogen, Blumeria graminis f. sp. avenae (B. graminis). Its presence influenced all measured parameters. The content of β-d-glucans in infected leaves decreased in all used varieties, compared to the non-infected plants, but not significantly. Oats reacted differently, with Aragon and Vaclav responding with overexpression, and Bay Yan 2, Ivory, and Racoon responding with the underexpression of these genes. Pathogens changed the relative ratios regarding the expression of CslF6, CslF9, and CslF3 genes from neutral to negative correlations. However, changes in the expression of these genes did not statistically significantly affect the content of β-d-glucans. A very slight indication of positive correlation, but statistically insignificant, was observed between the contents of β-d-glucans and chlorophylls. Some isoforms of β-1,3-glucanases accumulated to a several-times higher level in the infected leaves of all varieties. New isoforms of β-1,3-glucanases were also detected in infected leaves after fungal infection.
An Optical Algorithm for Relative Thickness of Each Monochrome Component in Multilayer Transparent Mixed Films
Authors: Wu Meiqin , Lu Zuoxiang , Li Yongrui , Yan Xiaofei , Chen Xuefei , Zeng Fangmeng , Zhu Chengyan
Published: August 2022

A modification of the two-flux Kubelka-Munk (K-M) model was proposed to describe the energy conservation of scattered light in colored mixed material with a defined scattered photometric, which is applied for the relative quantity distribution of each colored monochrome component in mixed material. A series of systematical experiments demonstrated a higher consistency with the reference quantity distribution than the common Lambert-Beer (L-B) law. Its application in the fibrogram of each component for measuring the cotton fiber’s length was demonstrated to be good, extending its applicability to white and dark colored blended fibers, the length of which is harder to measure using L-B law.
Special Issue “Bioprocess Systems Engineering Applications in Pharmaceutical Manufacturing”
Authors: Pörtner Ralf , Möller Johannes
Published: August 2022

Biopharmaceutical and pharmaceutical manufacturing are strongly influenced by the process analytical technology initiative (PAT) and quality by design (QbD) methodologies, which are designed to enhance the understanding of more integrated processes [...]
Effects of S and Mineral Elements (Ca, Al, Si and Fe) on Thermochemical Behaviors of Zn during Co-Pyrolysis of Coal and Waste Tire: A Combined Experimental and Thermodynamic Simulation Study
Authors: Lan Yaxin , Jin Shuangling , Wang Jitong , Wang Xiaorui , Zhang Rui , Ling Licheng , Jin Minglin
Published: August 2022

The transformation behaviors of Zn during co-pyrolysis of waste tires and coal were studied in a fixed-bed reaction system. The effects of pyrolysis temperature and the Zn content of coal mixture on the Zn distributions in the pyrolytic products (coke, tar and gas) were investigated in detail. It is found that the relative percentages of Zn in the pyrolytic products are closely related to the contents of S and mineral elements (Ca, Al, Si and Fe) in the coal. The thermodynamic equilibrium simulations conducted using FactSage 8.0 show that S, Al and Si can interact with Zn to inhibit the volatilization of Zn from coke. The reaction sequence with Zn is S > Al > Si, and the thermal stability of products is in the order of ZnS > ZnAl2O4 > Zn2SiO4. These results provide insights into the migration characteristics of Zn during co-pyrolysis of coal and waste tires, which is vital to the prevention and control of Zn emissions to reduce the environmental burden.
Influence of Chitosan and Glucono-δ-Lactone on the Gel Properties, Microstructural and Textural Modification of Pea-Based Tofu-Type Product
Authors: Jao Cheng-Hsun , Kuo Meng-I , Chen Chao-Jung , Hsieh Jung-Feng
Published: August 2022

This study investigated the effects of the addition of chitosan (0–1.0%) or glucono-δ-lactone (GDL) (0–60 mM) on the gel properties, microstructure, and texture of pea-based tofu-type product. Following the addition of 0.5% chitosan or 20 mM GDL, we observed a significant decrease in the hardness and cohesiveness of the tofu, resulting in a slightly discontinuous network structure with pores smaller than those in samples without chitosan or GDL. SDS-PAGE analysis revealed the induced aggregation of pea legumin (11S) and vicilin (7S) subunits (30, 34, and 50 kDa), legumin α subunit (40 kDa), and legumin β subunit (20 kDa) by chitosan or GDL. It appears that chitosan and GDL could potentially be used as food additives for the development of texture-modified pea-based tofu-type products.
Research on Erosion Wear of Slotted Screen Based on High Production Gas Field
Authors: Deng Fucheng , Yin Biao , Xiao Yunchen , Li Gang , Yan Chuanliang
Published: August 2022

Erosion wear is a common failure form of slotted screen in service. In this paper, based on CFD software and sand production data of a gas field in the Tarim Basin, the particle velocity and shear force at the slot of the flow field in the sieve tube were studied to determine the maximum area of erosion; at the same time, the velocity, viscosity, particle size and concentration of sand-carrying fluid were analyzed by orthogonal test, and the regression model of multi-factor maximum erosion rate was established. ① Through the analysis of the four factors on the degree of dependent variables, the order of the primary and secondary factors are: sand-carrying liquid flow rate, particle concentration, fluid viscosity, particle diameter, the effect of fluid viscosity and particle diameter on erosion rate is relatively small; ② According to the analysis of variance and range, the combination scheme of minimum erosion generation is obtained, and the calculation model of the erosion rate of the slotted screen is established. In order to reduce the erosion and abrasion in the actual oil and gas production process, the reasonable flow control and precise sand control method design and precision selection can be adopted; it provides a design basis for sand control and long-term effects of production in high-yield gas field.
Mechanical Strength, Water Seepage and Microstructure of a Novel Landfill Solidified Sludge Liner Material
Authors: Liu Yajun , Lu Haijun , Wang Chaofeng , Liu Ye , Ma Jiayu , Liu Mengyi
Published: August 2022

In order to prepare a novel landfill liner material, we used industrial calcium-containing waste (slag, fly ash, and desulfurized gypsum) to solidify municipal sludge. The mechanical and permeability properties of the solidified sludge material (SSM) were evaluated using straight shear, uniaxial compression, and permeability tests. The hydration products, microscopic morphology, and elemental composition of the SSM after the wet and dry cycles were analyzed using a combination of scanning electron microscopy (SEM + EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The SSM has high strength and low hydraulic conductivity. The values of cohesion c and internal friction angle φ reached 0.45–3.31 MPa and 6.52–36.28°. The SSM exhibited a compressive strength of 0.93–11.67 MPa and hydraulic conductivity of 4.80 × 10−9–1.34 × 10−7 cm/s. Analysis shows that SiO2, Al2O3, and CaO in industrial calcium-containing solid wastes and sludges produce dense bulk and agglomerated C-S-H and C-A-S-H gels under alkali excitation. The optimum ratio of sludge, desulfurized gypsum, fly ash, and slag in the solidified sludge was 1:0.61:0.62:0.54, whereas the optimum exciter was Ca(OH)2. The SSM may be used as a good barrier material to prevent water seepage in landfills.
Combustion Regime Identification in Turbulent Non-Premixed Flames with Principal Component Analysis, Clustering and Back-Propagation Neural Network
Authors: Zhang Hanlin , Lu Hao , Xie Fan , Ma Tianshun , Qian Xiang
Published: August 2022

Identifying combustion regimes is important for understanding combustion phenomena and the structure of flames. This study proposes a combustion regime identification (CRI) method based on rotated principal component analysis (PCA), clustering analysis and the back-propagation neural network (BPNN) method. The methodology is tested with large-eddy simulation (LES) data of two turbulent non-premixed flames. The rotated PCA computes the principal components of instantaneous multivariate data obtained in LES, including temperature, and mass fractions of chemical species. The frame front results detected using the clustering analysis do not rely on any threshold, indicating the quantitative characteristic given by the unsupervised machine learning provides a perspective towards objective and reliable CRI. The training and the subsequent application of the BPNN rely on the clustering results. Five combustion regimes, including environmental air region, co-flow region, combustion zone, preheat zone and fuel stream are well detected by the BPNN, with an accuracy of more than 98% using 5 scalars as input data. Results showed the computational cost of the trained supervised machine learning was low, and the accuracy was quite satisfactory. For instance, even using the combined data of CH4-T, the method could achieve an accuracy of more than 95% for the entire flame. The methodology is a practical method to identify combustion regime, and can provide support for further analysis of the flame characteristics, e.g., flame lift-off height, flame thickness, etc.
Prospects and Challenges of AI and Neural Network Algorithms in MEMS Microcantilever Biosensors
Authors: Wang Jingjing , Xu Baozheng , Shi Libo , Zhu Longyang , Wei Xi
Published: August 2022

This paper focuses on the use of AI in various MEMS (Micro-Electro-Mechanical System) biosensor types. Al increases the potential of Micro-Electro-Mechanical System biosensors and opens up new opportunities for automation, consumer electronics, industrial manufacturing, defense, medical equipment, etc. Micro-Electro-Mechanical System microcantilever biosensors are currently making their way into our daily lives and playing a significant role in the advancement of social technology. Micro-Electro-Mechanical System biosensors with microcantilever structures have a number of benefits over conventional biosensors, including small size, high sensitivity, mass production, simple arraying, integration, etc. These advantages have made them one of the development avenues for high-sensitivity sensors. The next generation of sensors will exhibit an intelligent development trajectory and aid people in interacting with other objects in a variety of scenario applications as a result of the active development of artificial intelligence (AI) and neural networks. As a result, this paper examines the fundamentals of the neural algorithm and goes into great detail on the fundamentals and uses of the principal component analysis approach. A neural algorithm application in Micro-Electro-Mechanical System microcantilever biosensors is anticipated through the associated application of the principal com-ponent analysis approach. Our investigation has more scientific study value, because there are currently no favorable reports on the market regarding the use of AI with Micro-Electro-Mechanical System microcantilever sensors. Focusing on AI and neural networks, this paper introduces Micro-Electro-Mechanical System biosensors using artificial intelligence, which greatly promotes the development of next-generation intelligent sensing systems, and the potential applications and prospects of neural networks in the field of microcantilever biosensors.
Modelling Deaggregation Due to Normal Carrier–Wall Collision in Dry Powder Inhalers
Authors: Alfano Francesca Orsola , Di Renzo Alberto , Gaspari Roberto , Benassi Andrea , Di Maio Francesco Paolo
Published: August 2022

Powder deaggregation in Dry Powder Inhalers (DPI) with carrier-based formulations is a key process for the effectiveness of drug administration. Carrier-wall collisions are one of the recognised mechanisms responsible for active pharmaceutical ingredient (API) aerosolisation, and DPI geometries are designed to maximise their efficacy. The detachment of fine and cohesive API particles is investigated at a fundamental level by simulating with DEM the normal collision of a carrier sphere with an API particle attached. The impact velocity at which detachment occurs (escape velocity) is determined as a function of key parameters, such as cohesiveness, coefficient of restitution, static and rolling friction. An analytical model for the escape velocity is then derived, examining the role of the initial position of the particle, cohesion model and particle size. Finally, the results are framed in the context of DPI inhalers, comparing the results obtained with impact velocities typically recorded in commercial devices.
Engineering Characterisation of Wearing Course Materials Modified with Waste Plastic
Authors: Mashaan Nuha
Published: August 2022

This review paper shows several sections of bitumen, asphalt mixtures, polymers, and waste plastic in pavement engineering. The paper reviews and evaluates the influence of using waste polymer in improving the rheological and engineering properties of the modified binder and mixtures. Evaluation of properties and design of stone mastic asphalt mixtures are reviewed. Reports and studies had investigated the advantages and importance of using polymer in bitumen modification; however, they yet show a gap in research in terms of the role of waste polymer in improving the durability, aging, and fatigue life in the long term of service.
Ming (Name) as the Bond of Individual and Community from the Perspective of Confucian Communitarianism
Authors: Zhang Jingjie
Published: August 2022

The relationship between the individual and the collective is one of the most important topics in Confucianism. Though this concept has been widely studied, ming 名 (meaning ‘name’), one of its most crucial categories, has not yet been deeply explored within this theoretical domain. This article discusses four aspects of ming and their contributions to the relationship between the self and community. Firstly, Confucius’ proposition of zhengming 正名 (rectifying names or the rectification of names) implies that language, especially that of rulers or gentlemen 君子 (junzi), has a considerable impact on both ethical and political practices. In this sense, ming as language establishes a relationship between rulers and the communities they govern. Secondly, in Confucius’ use of ming, reputation also reflects the attributes of a collectivity. On one hand, reputation functions as a social evaluation system; on the other, it can also be used to shape social values. Both aspects of language and reputation can be found in Confucius’ sayings, and are essentially determined by the sound attributes of ming. Thirdly, ming is interpreted to mean “role” in the later explanations and commentaries of Analects 13.3, which signifies that each individual has their own role in the community to which they belong. The position of a social individual is determined according to their relationship with others. Simultaneously, it is also the idea of “role” that brings a hierarchical order to family, state, clan, and “all under heaven”. Finally, the relationship between ming and yi 義 (appropriateness) implies the correlation between a name and the subject to which it refers. For ethical or political participants, yi means that the name-bearer is bound to a series of demands regarding their behaviors and virtues, which can lead to a “thick” conception of the subject, that is, the role of a complex of virtues, duties, and even rights (albeit implicit). Although the meaning of ming was becoming more complicated and profound during the development of early Confucianism, it has always functioned as the bond between individual and community. In this regard, the Confucian theory of ming can contribute some insights toward the combination of Confucianism and communitarianism, and also toward the modernization of Confucianism.
Levinas on the Relationship between Pleasure and the Good
Authors: Wang Guangyao , Jiang Longxiang
Published: August 2022

The article discusses the relationship between pleasure and the Good in Levinas’s ethics. Firstly, the paper points out that, for Levinas, pleasure and the Good are both essentially related to sensibility, except that pleasure is concerned with the self-affection of sensibility, and the Good is concerned with the hetero-affection of sensibility. The self-affection of pleasure and enjoyment enables the subject to locate and contract itself, and thus to establish an inner and separated self. Meanwhile, the Good is originated from the hetero-affection of the call of the transcendent Other, and is embodied in an involuntary suffering for the other’s suffering, weakness, and needs. Secondly, the paper argues that the relationship between pleasure and the Good is highly tensional. On the one hand, the Good does interrupt the egoism of life and its pleasure. On the other hand, pleasure actually constitutes a necessary condition for the Good, rather than something that must be rejected. The intersection of pleasure and the Good constitutes an insurmountable and irreducible tension within subjectivity. Finally, the paper places Levinas’s ethics in a dialogue with hedonism, virtue ethics, asceticism, and deontology, and regards Levinas’s ethics as a new paradigm for understanding the relationship between pleasure and the Good in the history of Western ethics.
The Efficiency of Foliar Kaolin Spray Assessed through UAV-Based Thermal Infrared Imagery
Authors: Pádua Luís , Bernardo Sara , Dinis Lia-Tânia , Correia Carlos , Moutinho-Pereira José , Sousa Joaquim J.
Published: August 2022

The water content in an agricultural crop is of crucial importance and can either be estimated through proximal or remote sensing techniques, allowing better irrigation scheduling and avoiding extreme water stress periods. However, the current climate change context is increasing the use of eco-friendly practices to reconcile water management and thermal protection from sunburn. These approaches aim to mitigate summer stress factors (high temperature, high radiation, and water shortage) and improve the plants’ thermal efficiency. In this study, data from unmanned aerial vehicles (UAVs) were used to monitor the efficiency of foliar kaolin application (5%) in a commercial vineyard. Thermal infrared imagery (TIR) was used to compare the canopy temperature of grapevines with and without kaolin and to compute crop water stress and stomatal conductance indices. The gas exchange parameters of single leaves were also analysed to ascertain the physiological performance of vines and validate the UAV-based TIR data. Generally, plants sprayed with kaolin presented a lower temperature compared to untreated plants. Moreover, UAV-based data also showed a lower water stress index and higher stomatal conductance, which relate to eco-physiological measurements carried out in the field. Thus, the suitability of UAV-based TIR data proved to be a good approach to monitor entire vineyards in regions affected by periods of heatwaves, as is the case of the analysed study area.
Comparison of KOMPSAT-5 and Sentinel-1 Radar Data for Soil Moisture Estimations Using a New Semi-Empirical Model
Authors: Tao Liangliang , Ryu Dongryeol , Western Andrew , Lee Sun-Gu
Published: August 2022

X-band KOMPSAT-5 provides a good perspective for soil moisture retrieval at high-spatial resolution over arid and semi-arid areas. In this paper, an intercomparison of KOMPSAT-5 and C-band Sentinel-1 radar data in soil moisture retrieval was conducted over agricultural fields in Wimmera, Victoria, Australia. Optical images from Sentinel-2 were also used to calculate the scattering contribution of vegetation. This study employed a new semi-empirical vegetation scattering model with a linear association of soil moisture with observed backscatter coefficient and vegetation indices. The Combined Vegetation Index (CVI) was proposed and first used to parameterize vegetation water content. As a result, the vegetation scattering model was developed to monitor soil moisture based on remotely sensed data and ground measurements. Application of the algorithm over dryland wheat field sites demonstrated that the estimated satellite-based soil moisture contents have good linear relationships with the ground measurements. The correlation coefficients (R) are 0.862 and 0.616, and the root mean square errors (RMSEs) have the values of 0.020 cm3/cm3 and 0.032 cm3/cm3 at X- and C-bands, respectively. Furthermore, the validation results also indicated that X-band provided higher consistent accuracy for soil moisture inversion than C-band. These results showed significant promise in retrieving soil moisture using KOMPSAT-5 and Sentinel-1 remotely sensed data at high-spatial resolution over agricultural fields, with subsequent uses for crop growth and yield estimation.
Revealing Annual Crop Type Distribution and Spatiotemporal Changes in Northeast China Based on Google Earth Engine
Authors: Liu Yaqun , Wang Jieyong
Published: August 2022

Northeast China (NEC) produces 1/4 of the grain and 1/3 of the commercial grain in China, and is essential for food security and a sustainable socio-ecological system development. However, long-term annual crop type distribution in this vital area remains largely unknown, compromising the scientific basis for planting structure adjustment and sustainable agriculture management. To this end, we integrated 111-dimensional MOD09A1 features, feature optimization and random forest algorithms on the Google Earth Engine (GEE) platform to classify annual crop types in the NEC during 2000–2020, and adopted multi-source spatial data and geostatistical methods to reveal anthropogenic and natural characteristics of crop type changes. The results demonstrated that sample-based classification accuracies were 84.73–86.93% and statistics-based R2 were 0.81–0.95. From 2000–2020, the sowing area of maize and rice increased by 11.92 × 106 ha (111.05%) and 4.03 × 106 ha (149.28%), whereas that of soybean and other crops decreased by 13.73 × 106 ha (−64.10%) and 1.03 × 106 ha (−50.94%), respectively. Spatially, maize expanded northwestward, rice expanded northeastward, and soybean demonstrated a south-north shrinkage. The soybean-to-maize shift was the main conversion type, and its area largely reduced from 8.68 × 106 ha in 2000–2010 to 4.15 × 106 ha in 2010–2020. Economic comparative benefit and climate change jointly affected crop types in NEC. Higher-benefits maize and rice were mainly planted in more convenient areas with more population and closer to settlements, roads and waterways. The planting of maize and rice required higher temperature and precipitation, and climate change in the NEC provided favorable conditions for their expansion toward high-latitude areas. The crop type changes in the NEC have boosted economic benefits, but increased water–carbon–energy costs. Thus, effective measures such as subsidy policies, ecological compensation, and knowledge-exchange should be implemented to aid crop type and rotation adjustment and ensure food-ecological security.
PBL Height Retrievals at a Coastal Site Using Multi-Instrument Profiling Methods
Authors: Tsikoudi Ioanna , Marinou Eleni , Vakkari Ville , Gialitaki Anna , Tsichla Maria , Amiridis Vassilis , Komppula Mika , Raptis Ioannis Panagiotis , Kampouri Anna , Daskalopoulou Vasiliki , Mihalopoulos Nikos , Giannakaki Eleni , Tombrou Maria , Flocas Helena
Published: August 2022

The objective of this study was the estimation of the dynamic evolution of the Planetary Boundary Layer (PBL) height, using advanced remote sensing measurements from Finokalia Station, where the Pre-TECT Campaign took place during 1–26 April 2017. PollyXT Raman Lidar and Halo Wind Doppler Lidar profiles were used to study the daily vertical evolution of the PBL. Wavelet Covariance Transform (WCT) and Threshold Method (TM) were performed on different products acquired from Lidars. According to the analysis, all methods and products are able to provide reasonable boundary-layer height estimates, each of them showing assets and barriers under certain conditions. Two cases are presented in detail, indicating the limited daytime evolution of a coastal area, the decisive role of wind speed-direction in the formation of a shallow or high boundary layer and the differences when using aerosols or turbulence as tracers for the PBL height retrieval. Comparison between the observed PBL and ECMWF model results was made, establishing the importance of actual PBL measurements, in coastal regions with complex topography.
Challenging Environments for Precise Mapping Using GNSS/INS-RTK Systems: Reasons and Analysis
Authors: Aldibaja Mohammad , Suganuma Naoki , Yoneda Keisuke , Yanase Ryo
Published: August 2022

This paper demonstrates the weakness of GNSS/INS-RTK (GIR) systems in mapping challenging environments because of obstruction and deflection of satellite signals. Thus, it emphasizes that the strategy of mapping companies to commercially provide maps using expensive GIR systems does not always work robustly. This limits the scalability of autonomous vehicle deployment in many road structures and modern cities. Accordingly, different critical environments in Tokyo have been analyzed and investigated to demonstrate the effects of the road structure complexity on the GIR map quality with highlighting the relevant reasons. Therefore, this paper is intended to be a reference to prove that the data of GIR systems cannot always be considered as ground truth and the integration of SLAM technologies into the mapping modules is very necessary to enable the levels four and five of autonomous driving.
Increasing the Lateral Resolution of 3D-GPR Datasets through 2D-FFT Interpolation with Application to a Case Study of the Roman Villa of Horta da Torre (Fronteira, Portugal)
Authors: Oliveira Rui Jorge , Caldeira Bento , Teixidó Teresa , Borges José Fernando , Carneiro André
Published: August 2022

The approach presented in this work uses an interpolation methodology to densify 3D-GPR datasets to sharpen the results obtained in GPR surveys carried out in an archaeological environment. It allows the estimation of missing data from the combined use of mathematical transforms, such as the Fourier and curvelet transforms, and predictive filters. This technique makes it possible to calculate the missing signal simply by meeting two requirements: the data in the frequency domain must be limited in a range of values and must be able to be represented by a distribution of Fourier coefficients (verified conditions). The INT-FFT algorithm uses an open-access routine (Suinterp, Seismic Unix) to interpolate the GPR B-scans based on seismic trace interpolation. This process uses automatic event identification routines by calculating spatial derivatives to identify discontinuities in space by detecting very subtle changes in the signal, thus allowing for more efficient interpolation without artifacts or signal deterioration. We successfully tested the approach using GPR datasets from the Roman villa of Horta da Torre (Fronteira, Portugal). The results showed an increase in the geometric sharpness of the GPR reflectors and did not produce any numerical artifacts. The tests performed to apply the methodology to GPR-3D data allowed for assessing the interpolation efficiency, the level of estimation of missing data, and the level of information lost when we chose to increase the distance between B-scans in the acquisition stage.
Advanced Classification of Ionospheric Troughs in the Morning and Evening Conditions
Authors: Karpachev Alexander
Published: August 2022

The separation and classification of ionospheric troughs in the winter evening and morning ionospheres of the southern hemisphere were performed using CHAMP satellite data for high solar activity (2000–2002). In the high-latitude ionosphere, the main ionospheric trough (MIT) was separated from the high-latitude trough (HLT). The separation was carried out using a thorough analysis of all the characteristic structures of the ionosphere in the framework of the auroral diffuse particle precipitation model. Two types of high-latitude troughs were identified: (1) a wide trough associated with zone II of diffuse precipitation on the poleward edge of the auroral oval and (2) a narrow trough of ionization, which is presumably associated with an electric field action. The poleward wall of MIT is as ever formed by diffuse precipitation in zone I on the equatorward edge of the auroral oval. The HLT and MIT separation is most difficult at the longitudes of the eastern hemisphere, where all structures are located at the highest latitudes and partially overlap. In the mid-latitude ionosphere, all the characteristic structures of the ionosphere were also identified and considered. MIT was separated from the ring ionospheric trough (RIT), which is formed by the decay processes of the magnetospheric ring current. The separation of MIT and RIT was performed based on an analysis of the prehistory of all geomagnetic disturbances during the period under study. In addition to the RIT, a decrease in the electron density equatorward of the MIT was found to be often formed at the America–Atlantic longitudes, which masks the MIT minimum. For completeness, all cases of a clearly defined polar cavity are also presented.
Combining Landsat 8 and Sentinel-2 Data in Google Earth Engine to Derive Higher Resolution Land Surface Temperature Maps in Urban Environment
Authors: Onačillová Katarína , Gallay Michal , Paluba Daniel , Péliová Anna , Tokarčík Ondrej , Laubertová Daniela
Published: August 2022

Thermal infrared (TIR) satellite imagery collected by multispectral scanners is important to map land surface temperature on a global scale. However, the TIR spectral bands are typically available in coarser spatial resolution than other multispectral bands of shorter wavelengths. Therefore, the spatial resolution of the derived land surface temperature (LST) is limited to around 100 m. This constrains the applications of such thermal satellite sensors in which finer detail of LST spatial pattern is relevant, especially in an urban environment where the land cover structure is complex. Among the missions deployed on the Earth’s orbit, NASA’s TIRS sensor onboard Landsat 8 and Landsat 9, and ASTER onboard Terra provide the highest spatial resolution of the thermal band. On the other hand, ESA’s Sentinel-2 multispectral imagery is collected at a higher spatial resolution of 10 m with a 5-day temporal resolution, but scanning in the TIR band is not available. This study makes use of the known relationship between LST and land cover metrics, such as the normalized difference vegetation index (NDVI), built-up index (NDBI), and water index (NDWI). We define a multiple linear regression model based on the spectral indices and LST derived from Landsat 8 data to inform the same model in which the equivalent spectral indices derived from Sentinel-2 are used to predict LST at 10 m resolution. Results of this approach are demonstrated in a case study for Košice city, Slovakia, where the multiple linear model based on Landsat 8 data achieved an R2 of 0.642. The correlation between the observed Landsat 8 LST and predicted LST from Sentinel-2 aggregated to the same resolution as the observed LST was high (r = 0.91). Despite the imperfections of the downscaling model, the derived LST at 10 m resolution provides a better perception of the LST field that can be easily associated with land cover features present in urban environment. The LST downscaling approach was implemented into Google Earth Engine. It provides a user-friendly online application that can be used for any city or urban region for generating a more realistic spatial pattern of LST than can be directly observed by contemporary Earth observation satellites. The tool aids in urban decision making and planning on how to mitigate overheating of cities to improve the life quality of their citizens.
A Comprehensive Comparison of Machine Learning and Feature Selection Methods for Maize Biomass Estimation Using Sentinel-1 SAR, Sentinel-2 Vegetation Indices, and Biophysical Variables
Authors: Xu Chi , Ding Yanling , Zheng Xingming , Wang Yeqiao , Zhang Rui , Zhang Hongyan , Dai Zewen , Xie Qiaoyun
Published: August 2022

Rapid and accurate estimation of maize biomass is critical for predicting crop productivity. The launched Sentinel-1 (S-1) synthetic aperture radar (SAR) and Sentinel-2 (S-2) missions offer a new opportunity to map biomass. The selection of appropriate response variables is crucial for improving the accuracy of biomass estimation. We developed models from SAR polarization indices, vegetation indices (VIs), and biophysical variables (BPVs) based on gaussian process regression (GPR) and random forest (RF) with feature optimization to retrieve maize biomass in Changchun, Jilin province, Northeastern China. Three new predictors from each type of remote sensing data were proposed based on the correlations to biomass measured in June, July, and August 2018. The results showed that a predictor combined by vertical-horizontal polarization (VV), vertical-horizontal polarization (VH), and the difference of VH and VV (VH-VV) derived from S-1 images of June, July, and August, respectively, with GPR and RF, provided a more accurate estimation of biomass (R2 = 0.81–0.83, RMSE = 0.40–0.41 kg/m2) than the models based on single SAR polarization indices or their combinations, or optimized features (R2 = 0.04–0.39, RMSE = 0.84–1.08 kg/m2). Among the S-2 VIs, the GPR model using a combination of ratio vegetation index (RVI) of June, normalized different infrared index (NDII) of July, and normalized difference vegetation index (NDVI) of August achieved a result with R2 = 0.83 and RMSE = 0.39 kg/m2, much better than single VIs or their combination, or optimized features (R2 of 0.31–0.77, RMSE of 0.47–0.87 kg/m2). A BPV predictor, combined with leaf chlorophyll content (CAB) in June, canopy water content (CWC) in July, and fractional vegetation cover (FCOVER) in August, with RF, also yielded the highest accuracy (R2 = 0.85, RMSE = 0.38 kg/m2) compared to that of single BPVs or their combinations, or optimized subset. Overall, the three combined predictors were found to be significant contributors to improving the estimation accuracy of biomass with GPR and RF methods. This study clearly sheds new insights on the application of S-1 and S-2 data on maize biomass modeling.
Modelling the Influence of Geological Structures in Paleo Rock Avalanche Failures Using Field and Remote Sensing Data
Authors: He Lingfeng , Francioni Mirko , Coggan John , Calamita Fernando , Eyre Matthew
Published: August 2022

This paper focuses on the back analysis of an ancient, catastrophic rock avalanche located in the small city of Lettopalena (Chieti, Italy). The integrated use of various investigation methods was employed for landslide analysis, including the use of traditional manual surveys and remote sensing (RS) mapping for the identification of geological structures. The outputs of the manual and RS surveys were then utilised to numerically model the landslide using a 2D distinct element method. A series of numerical simulations were undertaken to perform a sensitivity analysis to investigate the uncertainty of discontinuity properties on the slope stability analysis and provide further insight into the landslide failure mechanism. Both numerical modelling and field investigations indicate that the landslide was controlled by translational sliding along a folded bedding plane, with toe removal because of river erosion. This generated daylighting of the bedding plane, creating kinematic freedom for the landslide. The formation of lateral and rear release surfaces was influenced by the orientation of the discrete fracture network. Due to the presence of an anticline, the landslide region was constrained in the middle-lower section of the slope, where the higher inclination of the bedding plane was detected. The landslide is characterized by a step-path slip surface at the toe of the slope, which was observed both in the modelling and the field. This paper highlights the combined use of a geological model and numerical modelling to provide an improved understanding of the origin and development of rock avalanches under the influence of river erosion, anticline structures, and related faults and fractures.
Daily Evapotranspiration Estimations by Direct Calculation and Temporal Upscaling Based on Field and MODIS Data
Authors: Jiang Yazhen , Wang Junrui , Wang Yafei
Published: August 2022

Daily evapotranspiration (ET) integration is essential to various applications of agricultural water planning and management, ecohydrology, and energy balance studies. The constant reference evaporative fraction (EFr) temporal upscaling method has been proven to be efficient in extrapolating instantaneous ET to a daily timescale. Unlike upscaling methods, the direct calculation (DC) method developed in our previous study directly estimates daily ET without calculating instantaneous ET. The present study aimed to compare daily estimations of ET using the EFr and DC methods based on field and MODIS data at a site from the ChinaFLUX network. The estimation results were validated by eddy covariance (EC) ET both with and without the correction of energy imbalance. Based on field data, the results show that (i) the DC method performed with higher accuracy when compared to uncorrected EC measurements, while daily ET from both methods was overestimated; (ii) the DC method still performed better after the EC ET was corrected by the Residual Energy scheme, and the overestimations were significantly decreased; (iii) both methods performed best when compared with corrected ET by the Bowen Ratio scheme. The results from satellite data reveal that (i) the constant EFr method overestimated daily ET by a mean-bias-error (MBE) of 5.6 W/m2, and a root-mean-square error (RMSE) of 18.6 W/m2; and (ii) the DC method underestimated daily ET by a smaller MBE of −4.8 W/m2 and an RMSE of 22.5 W/m2. Therefore, the DC method has similar or better performance than the widely used constant EFr upscaling method and can estimate daily ET directly and effectively.
Dual-View Stereovision-Guided Automatic Inspection System for Overhead Transmission Line Corridor
Authors: Zhou Yaqin , Xu Chang , Dai Yunfeng , Feng Xingming , Ma Yunpeng , Li Qingwu
Published: August 2022

Overhead transmission line corridor detection is important to ensure the safety of power facilities. Frequent and uncertain changes in the transmission line corridor environment requires an efficient and autonomous UAV inspection system, whereas the existing UAV-based inspection systems has some shortcomings in control model and ground clearance measurement. For one thing, the existing manual control model has the risk of striking power lines because it is difficult for manipulators to judge the distance between the UAV fuselage and power lines accurately. For another, the ground clearance methods based on UAV usually depend on LiDAR (Light Detection and Ranging) or single-view visual repeat scanning, with which it is difficult to balance efficiency and accuracy. Aiming at addressing the challenging issues above, a novel UAV inspection system is developed, which can sense 3D information of transmission line corridor by the cooperation of the dual-view stereovision module and an advanced embedded NVIDIA platform. In addition, a series of advanced algorithms are embedded in the system to realize autonomous control of UAVs and ground clearance measurement. Firstly, an edge-assisted power line detection method is proposed to locate the power line accurately. Then, 3D reconstruction of the power line is achieved based on binocular vision, and the target flight points are generated in the world coordinate system one-by-one to guide the UAVs movement along power lines autonomously. In order to correctly detect whether the ground clearances are in the range of safety, we propose an aerial image classification based on a light-weight semantic segmentation network to provide auxiliary information categories of ground objects. Then, the 3D points of ground objects are reconstructed according to the matching points set obtained by an efficient feature matching method, and concatenated with 3D points of power lines. Finally, the ground clearance can be measured and detected according to the generated 3D points of the transmission line corridor. Tests on both corresponding datasets and practical 220-kV transmission line corridors are conducted. The experimental results of different modules reveal that our proposed system can be applied in practical inspection environments and has good performance.