bluuebunny/crossref_metadata_2025 huggingface dataset:
A Low-Cost Method for Phenotyping Wilting and Recovery of Wheat Leaves under Heat Stress Using Semi-Automated Image Analysis
Authors: Rascio Agata , De Santis Giuditta , Sorrentino Giuseppe
Published: June 2020

Leaf wilting is the most common symptom of dehydration stress. Methods to analyze this phenomenon are particularly relevant to evaluate crop agronomic performance, to genetically dissect out the wilting process, and for functional analysis of genetically modified plants. In this study, a low-cost, semi-automated method to quantify leaf folding of wilting plants is described that can replace visual analysis. Standardized heat-stress conditions were applied with a thermostatic drier, on plantlets or excised leaves from three wheat genotypes (Trinakria, Cappelli, and a Water-mutant of Trinakria). The best time–temperature binomial to record both the leaf wilting and recovery phases was identified using a free time-lapse application, by a smartphone camera. The quantitative description of the wilting phenomenon was obtained through the Kinovea software, which automatically tracked the leaf angle changes over time, computed various kinematic data (angular velocity, centripetal acceleration, total degrees of displacement) and constructed the graphs. The possibility of applying standardized heat-stress conditions and quantitatively describe the leaf folding kinematics means that this instrumentation and its use represents a very low cost tool for objective phenotyping of the degree of the heat-stress tolerance of wheat and of morphologically similar species.
Arabidopsis Ubiquitin-Conjugating Enzymes UBC7, UBC13, and UBC14 Are Required in Plant Responses to Multiple Stress Conditions
Authors: Feng Hui , Wang Sheng , Dong Dengfeng , Zhou Ruiyang , Wang Hong
Published: June 2020

Protein ubiquitination plays important roles in plants, including stress responses. The ubiquitin (Ub) E2 enzymes are required in the transfer of Ub to a substrate and are also important in determining the Ub-chain linkage specificity. However, for many of the 37 E2 genes in Arabidopsis thaliana, there is currently little or no understanding of their functions. In this study, we investigated three members of an E2 subfamily. The single, double, and triple mutants of UBC7, UBC13, and UBC14 did not show any phenotypic changes under normal conditions, but were more sensitive than the wild-type (WT) plants to multiple stress conditions, suggesting that the three genes are not critical for normal growth, but required in plant stress responses. The severity of the phenotypes increased from single to triple mutants, suggesting that the functions of the three genes are not completely redundant. The three E2s are closely related to the yeast Ubc7 and its homologs in animals and human, which are an important component of the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. The stress sensitivity phenotypes of the mutants and shared evolutionary root with the Ubc7 homologs in yeast and metazoans suggest that UBC7, UBC13, and UBC14 may function in the plant ERAD pathway.
Radiation Grafting of a Polymeric Prodrug onto Silicone Rubber for Potential Medical/Surgical Procedures
Authors: Magaña Hector , Becerra Claudia D. , Serrano-Medina Aracely , Palomino Kenia , Palomino-Vizcaíno Giovanni , Olivas-Sarabia Amelia , Bucio Emilio , Cornejo-Bravo José M.
Published: June 2020

Silicone rubber (SR) is a material used for medical procedures, with a common example of its application being in implants for cosmetic or plastic surgeries. It is also an essential component for the development of medical devices. SR was functionalized with the polymeric prodrug of poly(2-methacryloyloxy-benzoic acid) (poly(2MBA)) to render the analgesic anti-inflammatory drug salicylic acid by hydrolysis. The system was designed by functionalizing SR films (0.5 cm × 1 cm) with a direct grafting method, using gamma irradiation (60Co source) to induce the polymerization process. The absorbed dose (from 20 to 100 kGy) and the monomer concentration (between 0.4 and 1.5 M) were critical in controlling the surface and the bulk modifications of SR. Grafting poly(2MBA) onto SR (SR-g-2MBA) were characterized by attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy/energy-dispersive X-ray spectrometry, fluorescence microscopy, the contact angle, and the swelling. SR-g-2MBA demonstrated the drug’s sustained and pH-dependent release in simulated physiological mediums (pH = 5.5 and 7.4). The drug’s release was quantified by high-performance liquid chromatography and confirmed by gas chromatography–mass spectrometry. Finally, cytocompatibility was demonstrated in murine fibroblast and human cervical cancer cell lines. The developed systems provide new polymeric drug release systems for medical silicone applications.
Thermal and Mechanical Properties of the Biocomposites of Miscanthus Biocarbon and Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) (PHBV)
Authors: Li Zonglin , Reimer Christoff , Wang Tao , Mohanty Amar K. , Misra Manjusri
Published: June 2020

Miscanthus biocarbon (MB), a renewable resource-based, carbon-rich material, was melt-processed with poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) to produce sustainable biocomposites. The addition of the biocarbon improved the Young’s modulus of PHBV from 3.6 to 5.2 GPa at 30 wt % filler loading. An increase in flexural modulus, up to 48%, was also observed. On the other hand, the strength, elongation-at-break and impact strength decreased. Morphological study of the impact-fractured surfaces showed weak interaction at the interface and the existence of voids and agglomerates, especially with high filler contents. The thermal stability of the PHBV/MB composites was slightly reduced compared with the neat PHBV. The biocarbon particles were not found to have a nucleating effect on the polymer. The degradation of PHBV and the formation of unstable imperfect crystals were revealed by differential scanning calorimetry (DSC) analysis. Higher filler contents resulted in reduced crystallinity, indicating more pronounced effect on polymer chain mobility restriction. With the addition of 30 wt % biocarbon, the heat deflection temperature (HDT) became 13 degrees higher and the coefficient of linear thermal expansion (CLTE) decreased from 100.6 to 75.6 μm/(m·°C), desired improvement for practical applications.
Fabrication of Micro-Structured LED Diffusion Plate Using Efficient Micro Injection Molding and Micro-Ground Mold Core
Authors: Lu Yanjun , Luo Wang , Wu Xiaoyu , Xu Bin , Wang Chunjin , Li Jiajun , Li Liejun
Published: June 2020

In this paper, a new style of micro-structured LED (light-emitting diode) diffusion plate was developed using a highly efficient and precise hybrid processing method combined with micro injection molding and micro-grinding technology to realize mass production and low-cost manufacturing of LED lamps with excellent lighting performance. Firstly, the micro-structured mold core with controllable shape accuracy and surface quality was machined by the precision trued V-tip grinding wheel. Then, the micro-structured LED diffusion plate was rapidly fabricated by the micro injection molding technology. Finally, the influences of micro injection molding process parameters on the illumination of the micro-structured diffusion plate were investigated. The simulated optical results show that the illumination of the micro-structured diffusion plate can achieve a maximum value when the V-groove depth and V-groove angle are designed to be 300 μm and 60°, respectively. The experimental results indicate that the developed micro-structured diffusion plate may improve the illumination by about 40.82% compared with the traditional diffusion plate. The prediction accuracy of the designed light efficiency simulation method was about 90.33%.
Evolution of Interfacial Shear Strength and Mean Intrinsic Single Strength in Biobased Composites from Bio-Polyethylene and Thermo-Mechanical Pulp-Corn Stover Fibers
Authors: Tarrés Quim , Ardanuy Mònica
Published: June 2020

In this article, with the aim of promoting sustainability, contributing to the circular economy and the fight against climate change, the production of composite materials from Bio-polyethylene reinforced with corn stover fibers has been studied. The behavior of the materials obtained has been studied experimentally and by mathematical models of micromechanics. The composite materials were produced by extrusion and then injection with from 10 to 50 wt.% of fibers. The creation of a good fiber-matrix interface was studied by the incorporation of coupling agent between (0–8 wt.%). Increase of 131.2% on tensile strength for 40wt.% reinforcement was achieved by adding 6 wt.% of coupling agent. The correct interface was demonstrated by a correlation of 0.99 between the experimental results and the results of the mathematical models used.
Probing Interactions in Combined Hydroxide Base Solvents for Improving Dissolution of Cellulose
Authors: Swensson Beatrice , Larsson Anette , Hasani Merima
Published: June 2020

To further understand cellulose-solvent interactions in aqueous hydroxide solutions, cellulose behavior in aqueous solutions of NaOH combined with tetramethylammonium hydroxide (TMAH) or benzyltrimethylammonium hydroxide (Triton B), as well as urea, was investigated. The rheological properties of the solutions were assessed through flow sweeps at different temperatures, and the intermolecular interactions were probed using solvatochromic dyes. The results showed that NaOH combined with TMAH had synergistic effects on cellulose dissolution and was a better solvent for cellulose than the combination of NaOH with Triton B, in spite of the superior dissolution ability of Triton B alone. This somewhat unexpected finding shows that the base pair needs to be selected with care. Interestingly, addition of urea had no significant effect on the solvatochromic parameters or dissolution capacity of solutions of Triton B but rendered improved stability of solutions containing NaOH and/or TMAH. It seems that both urea and Triton B weaken the hydrophobic assembly effect of these solutions, but urea is excluded from interacting with cellulose in the presence of Triton B. This study provides further insight into dissolution of cellulose and the possibility of utilizing combinations of hydroxide bases to achieve improved solution properties.
Polystyrene Magnetic Nanocomposites as Antibiotic Adsorbents
Authors: Mohammadi Leili , Rahdar Abbas , Khaksefidi Razieh , Ghamkhari Aliyeh , Fytianos Georgios , Kyzas George Z.
Published: June 2020

There are different ways for antibiotics to enter the aquatic environment, with wastewater treatment plants (WWTP) considered to be one of the main points of entrance. Even treated wastewater effluent can contain antibiotics, since WWTP cannot eliminate the presence of antibiotics. Therefore, adsorption can be a sustainable option, compared to other tertiary treatments. In this direction, a versatile synthesis of poly(styrene-block-acrylic acid) diblock copolymer/Fe3O4 magnetic nanocomposite (abbreviated as P(St-b-AAc)/Fe3O4)) was achieved for environmental applications, and particularly for the removal of antibiotic compounds. For this reason, the synthesis of the P(St-b-AAc) diblock copolymer was conducted with a reversible addition fragmentation transfer (RAFT) method. Monodisperse superparamagnetic nanocomposite with carboxylic acid groups of acrylic acid was adsorbed on the surface of Fe3O4 nanoparticles. The nanocomposites were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) analysis. Then, the nanoparticles were applied to remove ciprofloxacin (antibiotic drug compound) from aqueous solutions. The effects of various parameters, such as initial drug concentration, solution pH, adsorbent dosage, and contact time on the process were extensively studied. Operational parameters and their efficacy in the removal of Ciprofloxacin were studied. Kinetic and adsorption isothermal studies were also carried out. The maximum removal efficiency of ciprofloxacin (97.5%) was found at an initial concentration of 5 mg/L, pH 7, adsorbent’s dosage 2 mg/L, contact time equal to 37.5 min. The initial concentration of antibiotic and the dose of the adsorbent presented the highest impact on efficiency. The adsorption of ciprofloxacin was better fitted to Langmuir isotherm (R2 = 0.9995), while the kinetics were better fitted to second-order kinetic equation (R2 = 0.9973).
Luminescent Properties of Lanthanoid-Poly(Sodium Acrylate) Composites: Insights on the Interaction Mechanism
Authors: Matsushita Alan F. Y. , Tapia María José , Pais Alberto A. C. C. , Valente Artur J. M.
Published: June 2020

The interaction between polyelectrolytes and metal ions is governed by different types of interactions, leading to the formation of different phases, from liquid state to weak gels, through an appropriate choice of metal ion/polyelectrolyte molar ratio. We have found that lanthanide ions, europium(III) and terbium(III), are able to form polymer composites with poly(sodium acrylate). That interaction enhances the luminescent properties of europium(III) and terbium(III), showing that Eu3+/poly(sodium acrylate) (PSA) and Tb3+/PSA composites have a highly intense red and green emission, respectively. The effect of cations with different valences on the luminescent properties of the polymer composites is analyzed. The presence of metal ions tends to quench the composite emission intensity and the quenching process depends on the cation, with copper(II) being by far the most efficient quencher. The interaction mechanism between lanthanoid ions and PSA is also discussed. The composites and their interactions with a wide range of cations and anions are fully characterized through stationary and non-stationary fluorescence, high resolution scanning electronic microscopy and X-ray diffraction.
Sustainable Catalytic Processes Driven by Graphene-Based Materials
Authors: Navalón Sergio , Ong Wee-Jun , Duan Xiaoguang
Published: June 2020

In the recent two decades, graphene-based materials have achieved great successes in catalytic processes towards sustainable production of chemicals, fuels and protection of the environment. In graphene, the carbon atoms are packed into a well-defined sp2-hybridized honeycomb lattice, and can be further constructed into other dimensional allotropes such as fullerene, carbon nanotubes, and aerogels. Graphene-based materials possess appealing optical, thermal, and electronic properties, and the graphitic structure is resistant to extreme conditions. Therefore, the green nature and robust framework make the graphene-based materials highly favourable for chemical reactions. More importantly, the open structure of graphene affords a platform to host a diversity of functional groups, dopants, and structural defects, which have been demonstrated to play crucial roles in catalytic processes. In this perspective, we introduced the potential active sites of graphene in green catalysis and showcased the marriage of metal-free carbon materials in chemical synthesis, catalytic oxidation, and environmental remediation. Future research directions are also highlighted in mechanistic investigation and applications of graphene-based materials in other promising catalytic systems.
Development of an Optimal Path Algorithm for Construction Equipment
Authors: Lee Hak June , Lim So Young
Published: June 2020

The fourth industrial revolution based on information and communication technology (ICT and IoT) is converging into the overall realm of technology, economy and society, creating innovative changes. In line with these changes, research is being actively carried out to integrate information and communication with automation at construction sites. This study was started to analyze problems arising from inefficient operation of construction equipment through analysis of risks arising at construction sites and to provide solutions related to these problems. In order to provide the optimal route of movement of construction equipment, an expert survey was conducted and an algorithm was developed to establish the optimal route of movement by analyzing the weights for each item of the survey. The adequacy of the algorithm was determined by comparing the developed algorithm with the actual data of the construction site in operation, and a safe and productive route as well as problems related to invisible safety are provided through the developed algorithm. Applying the optimal-route-generation algorithm conducted in this study to the construction site will not only increase productivity within the workplace, but also ultimately save time in operating equipment and increase safety.
Incremental Modeling and Monitoring of Embedded CPU-GPU Chips
Authors: Djedidi Oussama , Djeziri Mohand
Published: June 2020

This paper presents a monitoring framework to detect drifts and faults in the behavior of the central processing unit (CPU)-graphics processing unit (GPU) chips powering them. To construct the framework, an incremental model and a fault detection and isolation (FDI) algorithm are hereby proposed. The reference model is composed of a set of interconnected exchangeable subsystems that allows it to be adapted to changes in the structure of the system or operating modes, by replacing or extending its components. It estimates a set of variables characterizing the operating state of the chip from only two global inputs. Then, through analytical redundancy, the estimated variables are compared to the output of the system in the FDI module, which generates alarms in the presence of faults or drifts in the system. Furthermore, the interconnected nature of the model allows for the direct localization and isolation of any detected abnormalities. The implementation of the proposed framework requires no additional instrumentation as the used variables are measured by the system. Finally, we use multiple experimental setups for the validation of our approach and also proving that it can be applied to most of the existing embedded systems.
Control of Specific Growth Rate in Fed-Batch Bioprocesses: Novel Controller Design for Improved Noise Management
Authors: Brignoli Yann , Freeland Brian , Cunningham David , Dabros Michal
Published: June 2020

Accurate control of the specific growth rate (µ) of microorganisms is dependent on the ability to quantify the evolution of biomass reliably in real time. Biomass concentration can be monitored online using various tools and methods, but the obtained signal is often very noisy and unstable, leading to inaccuracies in the estimation of μ. Furthermore, controlling the growth rate is challenging as the process evolves nonlinearly and is subject to unpredictable disturbances originating from the culture’s metabolism. In this work, a novel feedforward-feedback controller logic is presented to counter the problem of noise and oscillations in the control variable and to address the exponential growth dynamics more effectively. The controller was tested on fed-batch cultures of Kluyveromyces marxianus, during which μ was estimated in real time from online biomass concentration measurements obtained with dielectric spectroscopy. It is shown that the specific growth rate can be maintained at different setpoint values with an average root mean square control error of 23 ± 6%.
Worldwide 3D Printers against the New Coronavirus
Authors: Fiorillo Luca , Leanza Teresa
Published: June 2020

The pandemic caused by the new coronavirus has placed national health systems of different countries in difficulty, and has demonstrated the need for many types of personal protective equipment (PPE). Thanks to the advent of new three-dimensional printing technologies, it was possible to share print files (using stereolithography (stl)) quickly and easily, improve them cooperatively, and allow anyone who possessed the materials, a suitable 3D printer and these files, to print. The possibility of being able to print three-dimensional supports, or complete personal protective equipment has been of incredible help in the management of COVID-19 (Coronavirus Disease 2019). The times and the relatively low costs have allowed a wide diffusion of these devices, especially for the structures that needed them, mainly healthcare facilities. 3D printing, now includes different fields of application, and represents, thanks to the evolution of methods and printers, an important step towards the “digital world”.
Prevalence of Meibomian Gland Dysfunction and Its Effect on Quality of Life and Ocular Discomfort in Patients with Prosthetic Eyes
Authors: Meduri Alessandro , Frisina Rino , Rechichi Miguel , Oliverio Giovanni William
Published: June 2020

Purpose: To evaluate the influence of ocular discomfort and meibomian gland dysfunction (MGD) on quality of life in patients with an ocular prosthesis. Methods: a prospective analysis was conducted on 18 patients with a unilateral ocular prosthesis. Evaluation of ocular discomfort symptoms, lid margin abnormalities (LMA), meibomian gland expression, meibography and a psychometric evaluation using the National Eye Institute Visual Function Questionnaire (NEI VFQ), Facial Appearance subscale of the Negative Physical Self Scale (NPSS-F), Hospital Anxiety and Depression Scale (HADS) and the DAS24 to evaluate anxiety and depression. Results: the statistically significant differences observed between normal and prosthetic eyes related to ocular symptoms and the meibography score (p = 0.0003). A negative correlation was reported between NEI VFQ score and meibography score (r = −0.509; p-value = 0.022). A positive correlation was detected with NPSS (r = 0.75; p-value < 0.0001), anxiety HADS score (r = 0.912; p-value = 0.001) and depression HADS score (r = 0.870; p-value > 0.0001). Conclusion: MGD represents the most common cause of evaporative dry eye disease, due to the reduction of the thickness of the lipid layer of the tear film. The occurrence of MGD in patients with prosthetic eyes is very common. Anxiety and depression were correlated to ocular discomfort and MGD, and this could affect the quality of life in patients with an ocular prosthesis.
Development of Hydrogen-Permselective Porous Membranes Using Radiation-Induced Graft Polymerization
Authors: Hasegawa Shin , Sawada Shinichi , Azami Shinya , Hagiwara Tokio , Hiroki Akihiro , Maekawa Yasunari
Published: June 2020

Hydrogen-permselective membranes were developed using a radiation-induced grafting method. Styrene (St) and acrylic acid (AAc) monomers were introduced into porous polyvinylidene fluoride (PVDF) membranes to obtain St- and AAc-grafted PVDF membranes with grafting degrees of 82% and 92%, respectively. The porosities of the grafted membranes were controlled in the range 30–40% by hot-press compression at 159 °C and 4 MPa. The hydrogen permeability was found to be of the order of 10−7 mol/m2∙s∙Pa, which was higher than the permeability for water vapor and nitrogen (oxygen model). The St- and AAc-grafted membranes exhibited 9.0 and 34 times higher permeability for H2 than for H2O and N2, respectively.
Seeking Solidarity between Protestant and Catholic Churches for Social Justice in Korea: The Case of the Korea Christian Action Organization for Urban Industrial Mission (Saseon) (1976–1989)
Authors: Kim Minah
Published: June 2020

The Korea Christian Action Organization for Urban Industrial Mission (Hanguk-gyohoe-sahoeseongyo-hyeubuihoe (Saseon)) was an organization which devoted itself not only to the Korean democratization movement against the military dictatorship, but also to the movement for the improvement of the quality of life of laborers, farmers, and the urban poor from 1976 to 1989. Saseon, a joint organization of Protestants and Catholics, trained activists dedicated to democratization and the people’s right to life movements. The Protestants and Catholics of Saseon believed that participation in social movements was missionary work building the Kingdom of God on Earth, and that they could set a good example of solidarity with a common goal of social justice and a mission for the poor which transcended their theological differences. This paper will illuminate the cooperation between Korean Protestant and Catholic churches toward the common goal of social justice, focusing on the case of Saseon.
The Cao Đài Deathscape: Reimagining Death, Funerals, and Salvation in Contemporary Vietnam
Authors: Jammes Jérémy , Shuai Shao Zhu
Published: June 2020

This article sheds light on the sophisticated funeral process set up by the Cao Đài religion (or Caodaism), combining both a theological and an ethnographical analysis. After introducing how Cao Đài theology represents both the body and the spiritual components of each individual in the specific millenarian conception of existence that characterizes Cao Đài, we trace the ritual process of funerals from the altar and coffin preparation to the collection of prayers and talismanic rituals conveyed to save souls in a Cao Đài manner. Read together, these sources present a genuine project and spirit of reform in the ideas, imaginaries, and practices related to death in Vietnam from the 1920s onwards, crystallizing a specific Cao Đài identity in Vietnamese and also East Asian redemptive societies’ deathscapes.
Responsible Materials Management for a Resource-Efficient and Low-Carbon Society
Authors: Mancini Lucia , Nuss Philip
Published: June 2020

Our societies rely on the quality and availability of natural resources. Driven by population growth, economic development, and innovation, future demand for natural resources is expected to further increase in coming decades. Raw materials will be an important part of society’s future material mix as countries increasingly transition towards resource-efficient and greenhouse-gas neutral economies. Raw materials are also fundamental to meet ecological and socio-economic targets within the UN Sustainable Development Agenda. For instance, they have a fundamental role in renewable energy technologies, new building materials and infrastructure, communication systems, and low-carbon transportation. However, some materials are largely supplied from countries with poor governance. The future availability of these materials and associated impacts are of increasing concern going forward. Recent raw material criticality studies have explored economic, geo-political, and technological factors that affect materials’ supply. However, environmental and social pressures also play a role in their security of supply. For instance, conflicts can prevent access to mineral deposits; accidents and environmental damage compromise public acceptance and can hinder future extraction operations. This article will introduce this Special Issue with a focus on material requirements and responsible sourcing of materials for a low-carbon society, and provides an overview of the subsequent research papers.
Improving Risk Assessments by Sanitary Inspection for Small Drinking-Water Supplies—Qualitative Evidence
Authors: Pond Katherine , King Richard , Herschan Jo , Malcolm Rosalind , McKeown Rory Moses , Schmoll Oliver
Published: June 2020

Small drinking-water supplies face particular challenges in terms of their management. Being vulnerable to contamination but often not monitored regularly nor well-maintained, small drinking-water supplies may pose consequences for health of users. Sanitary inspection (SI) is a risk assessment tool to identify and manage observable conditions of the water supply technology or circumstances in the catchment area that may favour certain hazardous events and introduce hazards which may become a risk to health. This qualitative research aimed to identify the strengths and weaknesses of the SI tool as published by the World Health Organisation to inform a review and update of the forms and to improve their robustness. The study identified a number of benefits of the approach, such as its simplicity and ease of use. Challenges were also identified, such as potential for inconsistencies in perception of risk between inspectors, in interpreting questions, and lack of follow-up action. The authors recommend a revision of the existing SI forms to address the identified challenges and development of complementary advice on possible remedial action to address identified risk factors and on basic operations and maintenance.
Critical Analysis of the Current State of Knowledge in the Field of Waste Heat Recovery in Sewage Systems
Authors: Piotrowska Beata , Słyś Daniel , Kordana-Obuch Sabina , Pochwat Kamil
Published: June 2020

The need for efficient use of energy and sustainable energy management and the fact that large quantities of heat are deposited in the discharged sewage have contributed to the development of research on waste heat recovery. Gray water began to be seen not just as waste, but also as an alternative source of energy. Research related to the development, improvement, and finally, the popularization of waste energy recovery devices and systems has evolved rapidly over the last two decades. Initially, technologies for gray water reuse were not widely used, which was due to the low efficiency of the current heat exchangers and the significant investment outlays that would have to be covered by potential users. Research conducted by scientists from around the world has allowed us to eliminate construction flaws, improve efficiency, and also provide information on the selection of optimal waste heat recovery technology, depending on the installation conditions and operating parameters. The ability to correctly select the device allows for effective energy collection from gray water, which improves the investment profitability. This paper reviews the research regarding issues related to waste heat recovery from gray water in sewage installations and systems. A critical analysis of the current state of knowledge was carried out with a special consideration to the technologies intended for the residential buildings.
Assessing the Effects of Photovoltaic Powerplants on Surface Temperature Using Remote Sensing Techniques
Authors: Zhang Xunhe , Xu Ming
Published: June 2020

The rapid development of photovoltaic (PV) powerplants in the world has drawn attention on their climate and environmental impacts. In this study, we assessed the effects of PV powerplants on surface temperature using 23 largest PV powerplants in the world with thermal infrared remote sensing technique. Our result showed that the installation of the PV powerplants had significantly reduced the daily mean surface temperature by 0.53 °C in the PV powerplant areas. The cooling effect with the installation of the PV powerplants was much stronger during the daytime than the nighttime with the surface temperature dropped by 0.81 °C and 0.24 °C respectively. This cooling effect was also depended on the capacity of the powerplants with a cooling rate of −0.32, −0.48, and −0.14 °C/TWh, respectively, for daily mean, daytime, and nighttime temperature. We also found that the construction of the powerplants significantly decreased the surface albedo from 0.22 to 0.184, but significantly increased the effective albedo (surface albedo plus electricity conversion) from 0.22 to 0.244, suggesting conversion of solar energy to electrical energy is a major contributor to the observed surface cooling. Our further analyses showed that the nighttime cooling in the powerplants was significantly correlated with the latitude and elevation of the powerplants as well as the annual mean temperature, precipitation, solar radiation, and normalized difference vegetation index (NDVI). This means the temperature effect of the PV powerplants depended on regional geography, climate and vegetation conditions. This finding can be used to guide the selection of the sites of PV powerplants in the future.
Different Approaches to Use Morphometric Attributes in Landslide Susceptibility Mapping Based on Meso-Scale Spatial Units: A Case Study in Rio de Janeiro (Brazil)
Authors: Canavesi Vanessa , Segoni Samuele , Rosi Ascanio , Ting Xiao , Nery Tulius , Catani Filippo , Casagli Nicola
Published: June 2020

Landslide susceptibility maps are widely used in landslide hazard management. Although many models have been proposed, mapping unit definition is a matter that still needs to be fully examined. In the literature, the most reported mapping units are pixels and slope units, while in this work, developed in the Rio de Janeiro region (Brazil), the use of drainage basins as a mapping unit is examined; even if their use leads to the definition of maps with a coarser spatial resolution than pixels-based maps, they convey information that can be easily and rapidly handled by civil defense organizations. However, for the morphometrical characterization of entire basins, a standardized procedure does not exist, and the susceptibility results may be sensitive to the approach used. To investigate this issue, a random forest model was used to assess landslide susceptibility, using 12 independent variables: four categorical (land use, soil type, lithology and slope orientation) and eight numerical variables (slope gradient, elevation, slope curvature, profile curvature, planar curvature, flow accumulation, topographic wetness index, stream power index). For each basin, the numerical variables were aggregated according to different approaches, which, in turn, were used to set up four different model configurations: i) maximum values, ii) mean values, iii) standard deviation values, iv) joint use of all the above. The resulting maps showed noticeable differences and a quantitative validation procedure showed that the best configurations were the ones based on mean values of independent variables, and the one based on the combination of all the values of the numerical variables. The main outcomes of this work consist of a landslide susceptibility map of the study area, to be used in operational procedures of risk management and in some insights on the best approaches to aggregate raster cell data into wider spatial units.
Challenges for In-Flight Calibration of Thermal Infrared Instruments for Earth Observation
Authors: Smith David , Peters Daniel , Nightingale Timothy , Pearce Jonathan , Veltcheva Radka
Published: June 2020

Satellite instruments operating in the thermal infrared wavelength range >3 µm provide information for applications such as land surface temperature (LST), sea surface temperatures (SST), land surface emissivity, land classification, soil composition, volcanology, fire radiative power, cloud masking, aerosols, and trace gases. All these instruments are dependent on blackbody (BB) calibration sources to provide the traceability of the radiometric calibration to SI (Système International d’Unités). A key issue for flight BB sources is to maintain the traceability of the radiometric calibration from ground to orbit. For example, the temperature of the BB is measured by a number of precision thermometers that are calibrated against a reference Standard Platinum Resistance Thermometer (SPRT) to provide the traceability to the International Temperature Scale of 1990 (ITS-90). However, once calibrated the thermometer system is subject to drifts caused by on-ground testing, the launch and space environments. At best the uncertainties due to thermometer ageing can only be estimated as there is no direct method for recalibrating. Comparisons with other satellite sensors are useful for placing an upper limit on calibration drifts but do not themselves provide a traceable link to the SI. In this paper, we describe we describe some of the technology developments, including phase change cells for use as reference standards, thermometer readout electronics and implementation of novel coatings, that are in progress to enhance the traceability of flight calibration systems in the thermal infrared.
Portable and Easily-Deployable Air-Launched GPR Scanner
Authors: García-Fernández María , Álvarez López Yuri , De Mitri Alessandro , Castrillo Martínez David , Álvarez-Narciandi Guillermo , Las-Heras Andrés Fernando
Published: June 2020

In recent years, Unmanned Aerial Vehicles (UAV)-based Ground Penetrating Radar (GPR) systems have been developed due to their advantages for safe and fast detection of Improvised Explosive Devices (IEDs) and landmines. The complexity of these systems requires performing extensive measurement campaigns in order to test their performance and detection capabilities. However, UAV flights are limited by weather conditions and battery autonomy. To overcome these problems, this contribution presents a portable and easily-deployable measurement setup which can be used as a testbed for the assessment of the capabilities of the airborne system. In particular, the proposed portable measurement setup replicates fairly well the conditions faced by the airborne system, which can hardly be reproduced in indoor GPR measurement facilities. Three validation examples are presented: the first two analyze the capability of the measurement setup to conduct experiments in different scenarios (loamy and sandy soils). The third example focuses on the problem of antenna phase center displacement with frequency and its impact on GPR imaging, proposing a simple technique to correct it.
Surface Mass Variations from GPS and GRACE/GFO: A Case Study in Southwest China
Authors: Zhong Bo , Li Xianpao , Chen Jianli , Li Qiong , Liu Tao
Published: June 2020

Surface mass variations inferred from the Global Positioning System (GPS), and observed by the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GFO) complement each other in terms of spatial and temporal coverage. This paper presents an analysis of regional surface mass variations inverted from GPS vertical displacements under different density distributions of GPS stations, and compares the GPS-derived mass variations with GRACE/GFO inversion results in spatial and temporal domains. To this end, GPS vertical displacement data from a total of 85 permanent GPS stations of the Crustal Movement Observation Network of China (CMONOC), the latest GRACE/GFO RL06 spherical harmonic (SH) solutions and GRACE RL06 mascon solutions are used to investigate surface mass variations in four regions or basins, including the Yunnan Province (YNP), Min River Basin (MRB), Jialing River Basin (JLRB), and Wu River Basin (WRB) in Southwest China. Our results showed that the spatial distributions and seasonal characteristics of GPS-derived mass change time series agree well with those from GRACE/GFO observations, especially in regions with relatively dense distributions of GPS stations (e.g., in the YNP and MRB), but there are still obvious discrepancies between the GPS and GRACE/GFO results. Scale factor methods (both basin-scaled and pixel-scaled) were employed to reduce the amplitude discrepancies between GPS and GRACE/GFO results. The results also showed that the one-year gap between the GRACE and GFO missions can be bridged by scaled GPS-derived mass change time series in the four studied regions, especially in the YNP and MRB regions (with relatively dense distributions of GPS stations).
Comparison of Satellite-Derived Sea Surface Temperature and Sea Surface Salinity Gradients Using the Saildrone California/Baja and North Atlantic Gulf Stream Deployments
Authors: Vazquez-Cuervo Jorge , Gomez-Valdes Jose , Bouali Marouan
Published: June 2020

Validation of satellite-based retrieval of ocean parameters like Sea Surface Temperature (SST) and Sea Surface Salinity (SSS) is commonly done via statistical comparison with in situ measurements. Because in situ observations derived from coastal/tropical moored buoys and Argo floats are only representatives of one specific geographical point, they cannot be used to measure spatial gradients of ocean parameters (i.e., two-dimensional vectors). In this study, we exploit the high temporal sampling of the unmanned surface vehicle (USV) Saildrone (i.e., one measurement per minute) and describe a methodology to compare the magnitude of SST and SSS gradients derived from satellite-based products with those captured by Saildrone. Using two Saildrone campaigns conducted in the California/Baja region in 2018 and in the North Atlantic Gulf Stream in 2019, we compare the magnitude of gradients derived from six different GHRSST Level 4 SST (MUR, OSTIA, CMC, K10, REMSS, and DMI) and two SSS (JPLSMAP, RSS40km) datasets. While results indicate strong consistency between Saildrone- and satellite-based observations of SST and SSS, this is not the case for derived gradients with correlations lower than 0.4 for SST and 0.1 for SSS products.
Camera Calibration for Coastal Monitoring Using Available Snapshot Images
Authors: Simarro Gonzalo , Calvete Daniel , Souto Paola , Guillén Jorge
Published: June 2020

Joint intrinsic and extrinsic calibration from a single snapshot is a common requirement in coastal monitoring practice. This work analyzes the influence of different aspects, such as the distribution of Ground Control Points (GCPs) or the image obliquity, on the quality of the calibration for two different mathematical models (one being a simplification of the other). The performance of the two models is assessed using extensive laboratory data (i.e., snapshots of a grid). While both models are able to properly adjust the GCPs, the simpler model gives a better overall performance when the GCPs are not well distributed over the image. Furthermore, the simpler model allows for better recovery of the camera position and orientation.
Recursive Feature Elimination and Random Forest Classification of Natura 2000 Grasslands in Lowland River Valleys of Poland Based on Airborne Hyperspectral and LiDAR Data Fusion
Authors: Demarchi Luca , Kania Adam , Ciężkowski Wojciech , Piórkowski Hubert , Oświecimska-Piasko Zuzanna , Chormański Jarosław
Published: June 2020

The use of hyperspectral (HS) and LiDAR acquisitions has a great potential to enhance mapping and monitoring practices of endangered grasslands habitats, beyond conventional botanical field surveys. In this study we assess the potentiality of recursive feature elimination (RFE) in combination with random forest (RF) classification in extracting the main HS and LiDAR features needed to map selected Natura 2000 grasslands along Polish lowland river valleys, in particular alluvial meadows 6440, lowland hay meadows 6510, and xeric and calcareous grasslands 6120. We developed an automated RFE-RF system capable to combine the potentials of both techniques and applied it to multiple acquisitions. Several LiDAR-based products and different spectral indices (SI) were computed and used as input in the system, with the aim of shedding light on the best-to-use features. Results showed a remarkable increase in classification accuracy when LiDAR and SI products are added to the HS dataset, strengthening in particular the importance of employing LiDAR in combination with HS. Using only the 24 optimal features selection generalized over the three study areas, strongly linked to the highly heterogeneous characteristics of the habitats and landscapes investigated, it was possible to achieve rather high classification results (K around 0.7–0.77 and habitats F1 accuracy around 0.8–0.85), indicating that the selected Natura 2000 meadows and dry grasslands habitats can be automatically mapped by airborne HS and LiDAR data. Similar approaches might be considered for future monitoring activities in the context of habitats protection and conservation.
Estimation of Surface Soil Moisture during Corn Growth Stage from SAR and Optical Data Using a Combined Scattering Model
Authors: Zhang Li , Lv Xiaolei , Chen Qi , Sun Guangcai , Yao Jingchuan
Published: June 2020

As an indispensable ecological parameter, surface soil moisture (SSM) is of great significance for understanding the growth status of vegetation. The cooperative use of synthetic aperture radar (SAR) and optical data has the advantage of considering both vegetation and underlying soil scattering information, which is suitable for SSM monitoring of vegetation areas. The main purpose of this paper is to establish an inversion approach using Terra-SAR and Landsat-7 data to estimate SSM at three different stages of corn growth in the irrigated area. A combined scattering model that can adequately represent the scattering characteristics of the vegetation coverage area is proposed by modifying the water cloud model (WCM) to reduce the effect of vegetation on the total SAR backscattering. The backscattering from the underlying soil is expressed by an empirical model with good performance in X-band. The modified water cloud model (MWCM) as a function of normalized differential vegetation index (NDVI) considers the contribution of vegetation to the backscattering signal. An inversion technique based on artificial neural network (ANN) is used to invert the combined scattering model for SSM estimation. The inversion method is established and verified using datasets of three different growth stages of corn. Using the proposed method, we estimate the SSM with a correlation coefficient R ≥ 0.72 and root-mean-square error R M S E ≤ 0.043 cm 3 /cm 3 at the emergence stage, with R ≥ 0.87 and R M S E ≤ 0.046 cm 3 /cm 3 at the trefoil stage and with R ≥ 0.70 and R M S E ≤ 0.064 cm 3 /cm 3 at the jointing stage. The results suggest that the method proposed in this paper has operational potential in estimating SSM from Terra-SAR and Landsat-7 data at different stages of early corn growth.
Optimal Walker Constellation Design of LEO-Based Global Navigation and Augmentation System
Authors: Guan Meiqian , Xu Tianhe , Gao Fan , Nie Wenfeng , Yang Honglei
Published: June 2020

Low Earth orbit (LEO) satellites located at altitudes of 500 km~1500 km can carry much stronger signals and move faster than medium Earth orbit (MEO) satellites at about a 20,000 km altitude. Taking advantage of these features, LEO satellites promise to make contributions to navigation and positioning where global navigation satellite system (GNSS) signals are blocked as well as the rapid convergence of precise point positioning (PPP). In this paper, LEO-based optimal global navigation and augmentation constellations are designed by a non-dominated sorting genetic algorithm III (NSGA-III) and genetic algorithm (GA), respectively. Additionally, a LEO augmentation constellation with GNSS satellites included is designed using the NSGA-III. For global navigation constellations, the results demonstrate that the optimal constellations with a near-polar Walker configuration need 264, 240, 210, 210, 200, 190 and 180 satellites with altitudes of 900, 1000, 1100, 1200, 1300, 1400 and 1500 km, respectively. For global augmentation constellations at an altitude of 900 km, for instance, 72, 91, and 108 satellites are required in order to achieve a global average of four, five and six visible satellites for an elevation angle above 7 degrees with one Walker constellation. To achieve a more even coverage, a hybrid constellation with two Walker constellations is also presented. On this basis, the GDOPs (geometric dilution of precision) of the GNSS with and without an LEO constellation are compared. In addition, we prove that the computation efficiency of the constellation design can be considerably improved by using master–slave parallel computing.