bluuebunny/crossref_metadata_2025 huggingface dataset:
Learning from Returned Products in a Closed Loop Supply Chain: A Systematic Literature Review
Authors: Ritola Ilkka , Krikke Harold , Caniëls Marjolein
Published: April 2020

Product returns are a source of valuable information that can be used by firms and supply chains to improve products, services, and decision making. However, firms are struggling to maximize the value of this information, and the extant scholarly literature is scattered among various research streams. Using a systematic literature review, the state-of-the-art of product returns informational value research and limitations in the current body of work were examined and future directions for research suggested. Three types of informational value were identified, namely operational information, product related information, and customer-related information, along with four value-creating factors, namely strategic information system (IS) decisions, organizational learning, information sharing, and technological solutions. Implications for practitioners are discussed. Lastly, the limitations are discussed, along with recommendations and directions for future research work.
Microwave Curing Characteristics of CFRP Composite Depending on Thickness Variation Using FBG Temperature Sensors
Authors: Kim Heonyoung , Kang Donghoon , Kim Moosun , Jung Min Hye
Published: April 2020

Microwave curing technology, which has seen increased commercialization recently due to its ability to cut the curing time and ensure high quality, requires an understanding of the curing characteristics of composite materials of varying thickness. Therefore, this study aimed to perform cure monitoring to evaluate the effects of variations in thickness on the quality of microwave curing. For this study, a fiber Bragg grating sensor was used to measure temperature changes in specimens during the curing cycle for cure monitoring which is generally used for optimization of the curing cycle; then, the time taken for temperature increase and overshoot of the specimen, and the times at which the specimen thickness varied, were quantitatively evaluated. Testing confirmed that microwave curing reduced the curing time in the sections in which the temperature rose; also, the specimen thickness caused overshoot of up to approximately 40 °C at the side, which can affect the curing quality of the composite materials. Furthermore, voids were observed on the side of all specimens. The results indicated that, in order to improve the quality of microwave curing of composite materials, the curing cycle should be optimized by considering the characteristics of the microwave curing equipment.
Distinctive Features of Graphene Synthesized in a Plasma Jet Created by a DC Plasma Torch
Authors: Shavelkina Marina , Ivanov Peter , Bocharov Aleksey , Amirov Ravil
Published: April 2020

Synthesis of graphene materials in a plasma stream from an up to 40 kW direct current (DC) plasma torch is investigated. These materials are created by means of the conversion of hydrocarbons under the pressure 350–710 Torr without using catalysts, without additional processes of inter-substrate transfer and the elimination of impurities. Helium and argon are used as plasma-forming gas, propane, butane, methane, and acetylene are used as carbon precursors. Electron microscopy and Raman imaging show that synthesis products represent an assembly of flakes varying in the thickness and the level of deformity. An occurrence of hydrogen in the graphene flakes is discovered by X-ray photoelectron spectroscopy, thermal analysis, and express-gravimetry. Its quantity depends on the type of carrier gas. Quasi-one-dimensional approach under the local thermodynamic equilibrium was used to investigate the evolution of the composition of helium and argon plasma jets with hydrocarbon addition. Hydrogen atoms appear in the hydrogen-rich argon jet under higher temperature. This shows that solid particles live longer in the hydrogen-rich environment compared with the helium case providing some enlargement of graphene with less hydrogen in its structure. In conclusion, graphene in flakes appears because of the volumetric synthesis in the hydrogen environment. The most promising directions of the practical use of graphеne flakes are apparently related to structural ceramics.
Digital Holographic Study of pH Effects on Anodic Dissolution of Copper in Aqueous Chloride Electrolytes
Authors: Yan Changqi , Yuan Boyu , Li Zhenhui , Li Liang , Wang Chao
Published: April 2020

The anodic dissolution of copper in chloride electrolytes with different pH has been investigated by using polarization measurements and digital holography. In acidic and neutral NaCl solutions, the oxidation processes of copper are almost the same: copper firstly dissolves as cuprous ions, which then produces the CuCl salt layer. The dissolution rate in the acidic solution is a little higher than that in the neutral. However, the mechanism is quite different in the alkaline NaCl solution: copper turns passive easily due to the formation of a relatively stable Cu2O film which results in pitting, and the dissolution rate of copper decreases before pit initiation.
Metabolomics Benefits from Orbitrap GC–MS—Comparison of Low- and High-Resolution GC–MS
Authors: Stettin Daniel , Poulin Remington X. , Pohnert Georg
Published: April 2020

The development of improved mass spectrometers and supporting computational tools is expected to enable the rapid annotation of whole metabolomes. Essential for the progress is the identification of strengths and weaknesses of novel instrumentation in direct comparison to previous instruments. Orbitrap liquid chromatography (LC)–mass spectrometry (MS) technology is now widely in use, while Orbitrap gas chromatography (GC)–MS introduced in 2015 has remained fairly unexplored in its potential for metabolomics research. This study aims to evaluate the additional knowledge gained in a metabolomics experiment when using the high-resolution Orbitrap GC–MS in comparison to a commonly used unit-mass resolution single-quadrupole GC–MS. Samples from an osmotic stress treatment of a non-model organism, the microalga Skeletonema costatum, were investigated using comparative metabolomics with low- and high-resolution methods. Resulting datasets were compared on a statistical level and on the level of individual compound annotation. Both MS approaches resulted in successful classification of stressed vs. non-stressed microalgae but did so using different sets of significantly dysregulated metabolites. High-resolution data only slightly improved conventional library matching but enabled the correct annotation of an unknown. While computational support that utilizes high-resolution GC–MS data is still underdeveloped, clear benefits in terms of sensitivity, metabolic coverage, and support in structure elucidation of the Orbitrap GC–MS technology for metabolomics studies are shown here.
Motion and Trajectory Constraints Control Modeling for Flexible Surgical Robotic Systems
Authors: Omisore Olatunji Mumini , Han Shipeng , Al-Handarish Yousef , Du Wenjing , Duan Wenke , Akinyemi Toluwanimi Oluwadara , Wang Lei
Published: April 2020

Success of the da Vinci surgical robot in the last decade has motivated the development of flexible access robots to assist clinical experts during single-port interventions of core intrabody organs. Prototypes of flexible robots have been proposed to enhance surgical tasks, such as suturing, tumor resection, and radiosurgery in human abdominal areas; nonetheless, precise constraint control models are still needed for flexible pathway navigation. In this paper, the design of a flexible snake-like robot is presented, along with the constraints model that was proposed for kinematics and dynamics control, motion trajectory planning, and obstacle avoidance during motion. Simulation of the robot and implementation of the proposed control models were done in Matlab. Several points on different circular paths were used for evaluation, and the results obtained show the model had a mean kinematic error of 0.37 ± 0.36 mm with very fast kinematics and dynamics resolution times. Furthermore, the robot’s movement was geometrically and parametrically continuous for three different trajectory cases on a circular pathway. In addition, procedures for dynamic constraint and obstacle collision detection were also proposed and validated. In the latter, a collision-avoidance scheme was kept optimal by keeping a safe distance between the robot’s links and obstacles in the workspace. Analyses of the results showed the control system was optimal in determining the necessary joint angles to reach a given target point, and motion profiles with a smooth trajectory was guaranteed, while collision with obstacles were detected a priori and avoided in close to real-time. Furthermore, the complexity and computational effort of the algorithmic models were negligibly small. Thus, the model can be used to enhance the real-time control of flexible robotic systems.
Calcium and/or Vitamin D Supplementation for the Prevention of Fragility Fractures: Who Needs It?
Authors: Reid Ian R , Bolland Mark J
Published: April 2020

Vitamin D and calcium have different biological functions, so the need for supplementation, and its safety and efficacy, need to be evaluated for each separately. Vitamin D deficiency is usually the result of low sunlight exposure (e.g., in frail older people, those who are veiled, those with dark-skin living at higher latitudes) and is reversible with calciferol 400–800 IU/day. Calcium supplements produce a 1% increase in bone density in the first year of use, without further increases subsequently. Vitamin D supplements do not improve bone density in clinical trials except in analyses of subgroups with baseline levels of 25-hydroxyvitamin D <30 nmol/L. Supplementation with calcium, vitamin D, or their combination does not prevent fractures in community-dwelling adults, but a large study in vitamin D-deficient nursing home residents did demonstrate fracture prevention. When treating osteoporosis, co-administration of calcium with anti-resorptive drugs has not been shown to impact on treatment efficacy. Correction of severe vitamin D deficiency (<25 nmol/L) is necessary before use of potent anti-resorptive drugs to avoid hypocalcemia. Calcium supplements cause gastrointestinal side effects, particularly constipation, and increase the risk of kidney stones and, probably, heart attacks by about 20%. Low-dose vitamin D is safe, but doses >4000 IU/day have been associated with more falls and fractures. Current evidence does not support use of either calcium or vitamin D supplements in healthy community-dwelling adults.
Association of Sugar-Sweetened Beverage Frequency with Adiposity: Evidence from the “Children of 1997” Birth Cohort
Authors: Zhang Ting , Au Yeung Shiu Lun , Kwok Man Ki , Hui Lai Ling , Leung Gabriel Matthew , Schooling C. Mary
Published: April 2020

Background: Observationally, sugar-sweetened beverage (SSB) consumption is associated with adiposity in Western children but could be confounded. We examined the association of SSB frequency with adiposity in the non-Western setting of Hong Kong. Methods: We examined the associations of SSB consumption frequency at 11 and 13 years assessed by using a food frequency questionnaire with subsequent body mass index (BMI) z-score and overweight/obesity up to 18 years using generalized estimating equations, and with waist circumference, waist-to-hip ratio, and body fat percentage at 16–19 years using linear regression in a population-representative Chinese birth cohort “Children of 1997” (n = 3628). Results: At 11 and 13 years, 6.8% and 8.2% of children respectively consumed SSB daily. Neither SSB frequency at 11 nor at 13 years was associated with subsequent BMI z-score or overweight/obesity up to 18 years, or with waist circumference, waist-to-hip ratio, or body fat percentage at 16–19 years adjusted for age, sex, socioeconomic position, health status, physical activity and other food consumption, although bias to the null from under-reporting cannot be eliminated. Conclusion: Although we cannot definitively exclude a small association of SSB frequency with adiposity, lack of association of SSB frequency with adiposity in a non-Western setting with low SSB consumption suggests that the role of SSB in adiposity appears to be minor.
Lack of Correlation between In Vitro and In Vivo Studies on the Inhibitory Effects of (‒)-Sophoranone on CYP2C9 Is Attributable to Low Oral Absorption and Extensive Plasma Protein Binding of (‒)-Sophoranone
Authors: Zheng Yu Fen , Bae Soo Hyeon , Huang Zhouchi , Chae Soon Uk , Jo Seong Jun , Shim Hyung Joon , Lee Chae Bin , Kim Doyun , Yoo Hunseung , Bae Soo Kyung
Published: April 2020

(‒)-Sophoranone (SPN) is a bioactive component of Sophora tonkinensis with various pharmacological activities. This study aims to evaluate its in vitro and in vivo inhibitory potential against the nine major CYP enzymes. Of the nine tested CYPs, it exerted the strongest inhibitory effect on CYP2C9-mediated tolbutamide 4-hydroxylation with the lowest IC50 (Ki) value of 0.966 ± 0.149 μM (0.503 ± 0.0383 μM), in a competitive manner. Additionally, it strongly inhibited other CYP2C9-catalyzed diclofenac 4′-hydroxylation and losartan oxidation activities. Upon 30 min pre-incubation of human liver microsomes with SPN in the presence of NADPH, no obvious shift in IC50 was observed, suggesting that SPN is not a time-dependent inactivator of the nine CYPs. However, oral co-administration of SPN had no significant effect on the pharmacokinetics of diclofenac and 4′-hydroxydiclofenac in rats. Overall, SPN is a potent inhibitor of CYP2C9 in vitro but not in vivo. The very low permeability of SPN in Caco-2 cells (Papp value of 0.115 × 10−6 cm/s), which suggests poor absorption in vivo, and its high degree of plasma protein binding (>99.9%) may lead to the lack of in vitro–in vivo correlation. These findings will be helpful for the safe and effective clinical use of SPN.
Nitrogen Enhances Salt Tolerance by Modulating the Antioxidant Defense System and Osmoregulation Substance Content in Gossypium hirsutum
Authors: Sikder Ripon Kumar , Wang Xiangru , Zhang Hengheng , Gui Huiping , Dong Qiang , Jin Dingsha , Song Meizhen
Published: April 2020

Increasing soil salinity suppresses both productivity and fiber quality of cotton, thus, an appropriate management approach needs to be developed to lessen the detrimental effect of salinity stress. This study assessed two cotton genotypes with different salt sensitivities to investigate the possible role of nitrogen supplementation at the seedling stage. Salt stress induced by sodium chloride (NaCl, 200 mmol·L−1) decreased the growth traits and dry mass production of both genotypes. Nitrogen supplementation increased the plant water status, photosynthetic pigment synthesis, and gas exchange attributes. Addition of nitrogen to the saline media significantly decreased the generation of lethal oxidative stress biomarkers such as hydrogen peroxide, lipid peroxidation, and electrolyte leakage ratio. The activity of the antioxidant defense system was upregulated in both saline and non-saline growth media as a result of nitrogen application. Furthermore, nitrogen supplementation enhanced the accumulation of osmolytes, such as soluble sugars, soluble proteins, and free amino acids. This established the beneficial role of nitrogen by retaining additional osmolality to uphold the relative water content and protect the photosynthetic apparatus, particularly in the salt-sensitive genotype. In summary, nitrogen application may represent a potential strategy to overcome the salinity-mediated impairment of cotton to some extent.
The Use of Urea and Kelp Waste Extract is A Promising Strategy for Maximizing the Biomass Productivity and Lipid Content in Chlorella sorokiniana
Authors: Kumbhar Ali Nawaz , He Meilin , Rajper Abdul Razzaque , Memon Khalil Ahmed , Rizwan Muhammad , Nagi Mostafa , Woldemicael Abeselom Ghirmai , Li Dan , Wang Chun , Wang Changhai
Published: April 2020

The decline in fossil fuel reserves has forced researchers to seek out alternatives to fossil fuels. Microalgae are considered to be a promising feedstock for sustainable biofuel production. Previous studies have shown that urea is an important nitrogen source for cell growth and the lipid production of microalgae. The present study investigated the effect of different concentrations of urea combined with kelp waste extract on the biomass and lipid content of Chlorella sorokiniana. The results revealed that the highest cell density, 20.36 × 107 cells−1, and maximal dry biomass, 1.70 g/L, were achieved in the presence of 0.5 g/L of urea combined with 8% kelp waste extract. Similarly, the maximum chlorophyll a, b and beta carotenoid were 10.36 mg/L, 7.05, and 3.01 mg/L, respectively. The highest quantity of carbohydrate content, 290.51 µg/mL, was achieved in the presence of 0.2 g/L of urea and 8% kelp waste extract. The highest fluorescence intensity, 40.05 × 107 cells−1, and maximum total lipid content (30%) were achieved in the presence of 0.1 g/L of urea and 8% kelp waste extract. The current study suggests that the combination of urea and kelp waste extract is the best strategy to enhance the biomass and lipid content in Chlorella sorokiniana.
Plant Defenses Against Tetranychus urticae: Mind the Gaps
Authors: Santamaria M. Estrella , Arnaiz Ana , Rosa-Diaz Irene , González-Melendi Pablo , Romero-Hernandez Gara , Ojeda-Martinez Dairon A. , Garcia Alejandro , Contreras Estefania , Martinez Manuel , Diaz Isabel
Published: April 2020

The molecular interactions between a pest and its host plant are the consequence of an evolutionary arms race based on the perception of the phytophagous arthropod by the plant and the different strategies adopted by the pest to overcome plant triggered defenses. The complexity and the different levels of these interactions make it difficult to get a wide knowledge of the whole process. Extensive research in model species is an accurate way to progressively move forward in this direction. The two-spotted spider mite, Tetranychus urticae Koch has become a model species for phytophagous mites due to the development of a great number of genetic tools and a high-quality genome sequence. This review is an update of the current state of the art in the molecular interactions between the generalist pest T. urticae and its host plants. The knowledge of the physical and chemical constitutive defenses of the plant and the mechanisms involved in the induction of plant defenses are summarized. The molecular events produced from plant perception to the synthesis of defense compounds are detailed, with a special focus on the key steps that are little or totally uncovered by previous research.
Heterotic Effect of Different Cytoplasmic Combinations in Sunflower Hybrids Cultivated Under Diverse Irrigation Regimes
Authors: Tyagi Vikrant , Dhillon Satwinder Kaur , Kaur Gurpreet , Kaushik Prashant
Published: April 2020

The sunflower hybrids hold a narrow cytoplasmic diversity. Besides, the heterotic effect of wild cytoplasmic combinations of sunflower on important traits under water stress has not been explored in detail. Here, we evaluated the different sunflower cytoplasmic combinations in sunflower hybrids using cytoplasmic male sterile (CMS) sources as female parents. We used a total of sixteen sunflower genotypes representing twelve CMS lines from wild and conventional sources along with four restorer lines. Twelve CMS lines were crossed with four restorer lines to develop a total of 48 F1 hybrid combinations. The hybrids were evaluated under two different environments (i.e., regular irrigation and water stress) for morphophysiological, yield, and biochemical traits over two years. Heterotic effect for various CMS sources was evaluated on all of the three possible scales, namely, better-parent heterosis (BPH), mid-parent heterosis (MPH), and heterosis as percent of check (PSH-996). For better-parent and mid-parent heterosis, the CMS sources Helianthus annuus, Helianthus argophyllus, and Helianthus debilis demonstrated positive better-parent heterosis for seed yield, oil content, and oleic acid irrespective of the environment. However, the hybrid combinations of different sources when using the genotype RCR8297 as the restorer parent recorded maximum average returns. Furthermore, chlorophyll meter (SPAD) reading positively correlated with days to 50% flowering, days to maturity, plant height, and number of leaves per plant in both the environments. Overall, this study identified and compared the heterotic effect of the different cytoplasmic combinations in sunflower under water stress as well as under normal irrigation environments.
Assembly and Analysis of the Complete Mitochondrial Genome of Capsella bursa-pastoris
Authors: Omelchenko Denis O. , Makarenko Maxim S. , Kasianov Artem S. , Schelkunov Mikhail I. , Logacheva Maria D. , Penin Aleksey A.
Published: April 2020

Shepherd’s purse (Capsella bursa-pastoris) is a cosmopolitan annual weed and a promising model plant for studying allopolyploidization in the evolution of angiosperms. Though plant mitochondrial genomes are a valuable source of genetic information, they are hard to assemble. At present, only the complete mitogenome of C. rubella is available out of all species of the genus Capsella. In this work, we have assembled the complete mitogenome of C. bursa-pastoris using high-precision PacBio SMRT third-generation sequencing technology. It is 287,799 bp long and contains 32 protein-coding genes, 3 rRNAs, 25 tRNAs corresponding to 15 amino acids, and 8 open reading frames (ORFs) supported by RNAseq data. Though many repeat regions have been found, none of them is longer than 1 kbp, and the most frequent structural variant originated from these repeats is present in only 4% of the mitogenome copies. The mitochondrial DNA sequence of C. bursa-pastoris differs from C. rubella, but not from C. orientalis, by two long inversions, suggesting that C. orientalis could be its maternal progenitor species. In total, 377 C to U RNA editing sites have been detected. All genes except cox1 and atp8 contain RNA editing sites, and most of them lead to non-synonymous changes of amino acids. Most of the identified RNA editing sites are identical to corresponding RNA editing sites in A. thaliana.
Evaluation of the Suitability of Poly(Lactide)/Poly(Butylene-Adipate-co-Terephthalate) Blown Films for Chilled and Frozen Food Packaging Applications
Authors: Pietrosanto Arianna , Scarfato Paola , Di Maio Luciano , Nobile Maria Rossella , Incarnato Loredana
Published: April 2020

The use of biopolymers can reduce the environmental impact generated by plastic materials. Among biopolymers, blends made of poly(lactide) (PLA) and poly(butylene-adipate-co-terephthalate) (PBAT) prove to have adequate performances for food packaging applications. Therefore, the present work deals with the production and the characterization of blown films based on PLA and PBAT blends in a wide range of compositions, in order to evaluate their suitability as chilled and frozen food packaging materials, thus extending their range of applications. The blends were fully characterized: they showed the typical two-phase structure, with a morphology varying from fibrillar to globular in accordance with their viscosity ratio. The increase of PBAT content in the blends led to a decrease of the barrier properties to oxygen and water vapor, and to an increase of the toughness of the films. The mechanical properties of the most ductile blends were also evaluated at 4 °C and −25 °C. The decrease in temperature caused an increase of the stiffness and a decrease of the ductility of the films to a different extent, depending upon the blend composition. The blend with 40% of PLA revealed to be a good candidate for chilled food packaging applications, while the blend with a PLA content of 20% revealed to be the best composition as frozen food packaging material.
Evaluation of Nanocomposite Made of Polylactic Acid and Nanocellulose from Carrot Pomace Modified with Silver Nanoparticles
Authors: Szymańska-Chargot Monika , Chylińska Monika , Pieczywek Piotr M. , Walkiewicz Anna , Pertile Giorgia , Frąc Magdalena , Cieślak Krystian J. , Zdunek Artur
Published: April 2020

In this research, it was proposed to use carrot cellulose nanofibrils (CCNF) isolated from carrot pomace modified with silver nanoparticles (AgNPs) as a filler of polylactic acid (PLA) composites matrix. The new procedure was based on two steps: first, the preparation of nanocellulose modified with metal nanoparticles, and then the combination with PLA. Two concentrations—0.25 mM and 2 mM—of AgNO3 were used to modify CCNF. Then, PLA was mixed with the filler (CCNF/AgNPs) in two proportions 99:1 and 96:4. The influence of CCNF/AgNPs on mechanical, hydrophilic, thermal, and antibacterial properties of obtained nanocomposites was evaluated. The greatest improvement of mechanical properties was observed for composite containing CCNF with 2 mM of AgNPs, which obtained the lowest Young modulus and highest strain at break. The degradation temperature was lower for PLA with CCNF/AgNPs, but crystallization temperature wasn’t influenced. The addition of CCNF/AgNPs also increased hydrophilicity. The transmission rates of oxygen, nitrogen, and carbon dioxide also increased after the addition of CCNF/AgNPs to PLA. The antibacterial function against Escherichia coli and Bacillus cereus was obtained after the addition of AgNPs but only at the contact surface with the material made, suggesting the lack of migration of nanoparticles from the composite.
Phase Behavior and Phase Diagram of Polystyrene-b-Poly(Perfluorooctylethyl Acrylates)
Authors: Shao Yu , Dai Hui , Zhao Meng , Li Bin , Yao Jianan , Zhang Wen-Bin , Li Hui
Published: April 2020

Fluorocontaining polymers bearing special properties are unique and important materials in modern society. In this work, we focused on the phase behavior and phase diagram of poly(styrene-block-perfluorooctylethyl acrylate) with a volume fraction varying from 0.2 to 0.8. Small-angle X-ray scattering and transmission electron microscopy showed the phase formation in the sequence of hexagonally packed cylinders (HEX) to lamellar layers (LAM) to inverse hexagonally packed cylinders (iHEX) in this series of block polymers. Wide-angle X-ray diffraction experiments proved that the fluorodomains of the LAM phases and the matrix of iHEX phases contained layered structures formed by the crystallization of fluorosegments. During heating, the self-assembled lattice remained intact even after the melting of fluorodomain, with barely changed lattice parameters. Such hierarchical structural formation was understood by chain conformation and domain interaction, which may provide new insight into the molecular design of advanced materials.
Sorting Liquid Droplets by Surface Tension Using Devices with Quasi-Superamphiphobic Coatings
Authors: Zhang Yu-Ping , Fan Di , Bai Xiu-Zhi , Cui Cheng-Xing , Chen Jun , Li Ren-Long , Liu Peng-Fei , Qu Ling-Bo
Published: April 2020

Any solid surface with homogenous or varying surface energy can spontaneously show variable wettability to liquid droplets with different or identical surface tensions. Here, we studied a glass slide sprayed with a quasi-superamphiphobic coating consisting of a hexane suspension of perfluorosilane-coated nanoparticles. Four areas on the glass slide with a total length of 7.5 cm were precisely tuned via ultraviolet (UV) irradiation, and droplets with surface tensions of 72.1–33.9 mN m−1 were categorized at a tilting angle of 3°. Then, we fabricated a U-shaped device sprayed with the same coating and used it to sort the droplets more finely by rolling them in the guide groove of the device to measure their total rolling time and distance. We found a correlation between ethanol content/surface tension and rolling time/distance, so we used the same device to estimate the alcoholic strength of Chinese liquors and to predict the surface tension of ethanol aqueous solutions.
3D Printing beyond Dentistry during COVID 19 Epidemic: A Technical Note for Producing Connectors to Breathing Devices
Authors: Cavallo Leonardo , Marcianò Antonia , Cicciù Marco , Oteri Giacomo
Published: April 2020

(1) Background: To mitigate the shortage of respiratory devices during the Covid-19 epidemic, dental professional volunteers can contribute to create printed plastic valves, adapting the dental digital workflow and converting snorkeling masks in emergency CPAP (continuous positive airways pressure) devices. The objective of this report was to provide the specific settings to optimize printing with the 3D printers of the dental industry. (2) Methods: In order to provide comprehensive technical notes to volunteer dental professionals interested in printing Charlotte and Dave connectors to breathing devices, the entire digital workflow is reported. (3) Results: The present paper introduces an alternative use of the dental Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) machinery, and reports on the fabrication of a 3D printed connection prototypes suitable for connection to face masks, thereby demonstrating the feasibility of this application. (4) Conclusions: This call for action was addressed to dentists and dental laboratories who are willing to making available their experience, facilities and machinery for the benefit of patients, even way beyond dentistry.
Evaluation of Hunting-Based Optimizers for a Quadrotor Sliding Mode Flight Controller
Authors: Oliveira Josenalde , Oliveira Paulo Moura , Boaventura-Cunha José , Pinho Tatiana
Published: April 2020

The design of Multi-Input Multi-Output nonlinear control systems for a quadrotor can be a difficult task. Nature inspired optimization techniques can greatly improve the design of non-linear control systems. Two recently proposed hunting-based swarm intelligence inspired techniques are the Grey Wolf Optimizer (GWO) and the Ant Lion Optimizer (ALO). This paper proposes the use of both GWO and ALO techniques to design a Sliding Mode Control (SMC) flight system for tracking improvement of altitude and attitude in a quadrotor dynamic model. SMC is a nonlinear technique which requires that its strictly coupled parameters related to continuous and discontinuous components be correctly adjusted for proper operation. This requires minimizing the tracking error while keeping the chattering effect and control signal magnitude within suitable limits. The performance achieved with both GWO and ALO, considering realistic disturbed flight scenarios are presented and compared to the classical Particle Swarm Optimization (PSO) algorithm. Simulated results are presented showing that GWO and ALO outperformed PSO in terms of precise tracking, for ideal and disturbed conditions. It is shown that the higher stochastic nature of these hunting-based algorithms provided more confidence in local optima avoidance, suggesting feasibility of getting a more precise tracking for practical use.
European Radiometry Buoy and Infrastructure (EURYBIA): A Contribution to the Design of the European Copernicus Infrastructure for Ocean Colour System Vicarious Calibration
Authors: Liberti Gian Luigi , D’Alimonte Davide , di Sarra Alcide , Mazeran Constant , Voss Kenneth , Yarbrough Mark , Bozzano Roberto , Cavaleri Luigi , Colella Simone , Cesarini Claudia , Kajiyama Tamito , Meloni Daniela , Pomaro Angela , Volpe Gianluca , Yang Chunxue , Zagolski Francis , Santoleri Rosalia
Published: April 2020

In the context of the Copernicus Program, EUMETSAT prioritizes the creation of an ocean color infrastructure for system vicarious calibration (OC-SVC). This work aims to reply to this need by proposing the European Radiometry Buoy and Infrastructure (EURYBIA). EURYBIA is designed as an autonomous European infrastructure operating within the Marine Optical Network (MarONet) established by University of Miami (Miami, FL, USA) based on the Marine Optical Buoy (MOBY) experience and NASA support. MarONet addresses SVC requirements in different sites, consistently and in a traceable way. The selected EURYBIA installation is close to the Lampedusa Island in the central Mediterranean Sea. This area is widely studied and hosts an Atmospheric and Oceanographic Observatory for long-term climate monitoring. The EURYBIA field segment comprises off-shore and on-shore infrastructures to manage the observation system and perform routine sensors calibrations. The ground segment includes the telemetry center for data communication and the processing center to compute data products and uncertainty budgets. The study shows that the overall uncertainty of EURYBIA SVC gains computed for the Sentinel-3 OLCI mission under EUMETSAT protocols is of about 0.05% in the blue-green wavelengths after a decade of measurements, similar to that of the reference site in Hawaii and in compliance with requirements for climate studies.
Unsupervised and Supervised Feature Extraction Methods for Hyperspectral Images Based on Mixtures of Factor Analyzers
Authors: Zhao Bin , Ulfarsson Magnus O. , Sveinsson Johannes R. , Chanussot Jocelyn
Published: April 2020

This paper proposes three feature extraction (FE) methods based on density estimation for hyperspectral images (HSIs). The methods are a mixture of factor analyzers (MFA), deep MFA (DMFA), and supervised MFA (SMFA). The MFA extends the Gaussian mixture model to allow a low-dimensionality representation of the Gaussians. DMFA is a deep version of MFA and consists of a two-layer MFA, i.e, samples from the posterior distribution at the first layer are input to an MFA model at the second layer. SMFA consists of single-layer MFA and exploits labeled information to extract features of HSI effectively. Based on these three FE methods, the paper also proposes a framework that automatically extracts the most important features for classification from an HSI. The overall accuracy of a classifier is used to automatically choose the optimal number of features and hence performs dimensionality reduction (DR) before HSI classification. The performance of MFA, DMFA, and SMFA FE methods are evaluated and compared to five different types of unsupervised and supervised FE methods by using four real HSIs datasets.
An Autonomous Wireless Device for Real-Time Monitoring of Water Needs
Authors: Borrero Juan D. , Zabalo Alberto
Published: April 2020

The agri-food sector is in constantly renewing, continuously demanding new systems that facilitate farmers´ work. Efficient agricultural practices are essential to increasing farm profitability, and reducing water consumption can be achieved by real-time monitoring of water needs. However, the prices of automatic systems for collecting data from several sources (soil and climate) are expensive and their autonomy is very low. This paper presents a low-consumption solution using the Internet of Things (IoT) based on wireless sensor networks (WSNs) and long-range wide-area network (LoRaWAN) technologies. By means of low-power wide-area network (LPWAN) communication, a farmer can monitor the state of crops in real time thanks to a large number of sensors connected wirelessly and distributed across the farm. The wireless sensor node developed, called BoXmote, exhibits very low power, since it has been optimized both in terms of hardware and software. The result is a higher degree of autonomy than commercial motes. This will allow the farmer to have access to all of the information necessary to achieve an efficient irrigation management of his crops with full autonomy.
An Energy Efficient and Secure IoT-Based WSN Framework: An Application to Smart Agriculture
Authors: Haseeb Khalid , Ud Din Ikram , Almogren Ahmad , Islam Naveed
Published: April 2020

Wireless sensor networks (WSNs) have demonstrated research and developmental interests in numerous fields, like communication, agriculture, industry, smart health, monitoring, and surveillance. In the area of agriculture production, IoT-based WSN has been used to observe the yields condition and automate agriculture precision using various sensors. These sensors are deployed in the agricultural environment to improve production yields through intelligent farming decisions and obtain information regarding crops, plants, temperature measurement, humidity, and irrigation systems. However, sensors have limited resources concerning processing, energy, transmitting, and memory capabilities that can negatively impact agriculture production. Besides efficiency, the protection and security of these IoT-based agricultural sensors are also important from malicious adversaries. In this article, we proposed an IoT-based WSN framework as an application to smart agriculture comprising different design levels. Firstly, agricultural sensors capture relevant data and determine a set of cluster heads based on multi-criteria decision function. Additionally, the strength of the signals on the transmission links is measured while using signal to noise ratio (SNR) to achieve consistent and efficient data transmissions. Secondly, security is provided for data transmission from agricultural sensors towards base stations (BS) while using the recurrence of the linear congruential generator. The simulated results proved that the proposed framework significantly enhanced the communication performance as an average of 13.5% in the network throughput, 38.5% in the packets drop ratio, 13.5% in the network latency, 16% in the energy consumption, and 26% in the routing overheads for smart agriculture, as compared to other solutions.
The Spillover Effect of US Industrial Subsidies on China’s Exports
Authors: Lou Yanfeng , Tian Yezhuang , Wang Kai
Published: April 2020

This study systematically assessed the spillover effects of US industrial subsidy policies on China’s export by matching all related bills issued by the US federal and state governments since 2009 with the affected products exported from China. In general, the US subsidy policies created a significant obstacle for Chinese exporters entering the US market. In addition, the industry-level analysis indicated that the subsidy policy has the most significant negative spillover effect on mid- and high-tech products, and no significant impact on resource-based and low-tech export products. Furthermore, we explored the mechanism and found that the US subsidies lower the domestic export prices of the affected products, thereby having a larger negative impact on the entry of mid- and high-tech products entering the US market. The implementation of the US subsidy increased the export competitiveness of mid- and high-tech products in domestic market, which helped such US firms expand their international markets. Therefore, we offer targeted suggestions in order to create a fair and reasonable business environment for Chinese exporters.
India’s Urban System: Sustainability and Imbalanced Growth of Cities
Authors: Shaban Abdul , Kourtit Karima , Nijkamp Peter
Published: April 2020

This paper maps out the structure and relative dynamics of cities of various size classes in India. It aims to address their hierarchical distribution, by employing the rank-size rule, Gibrat’s law, and a primacy index. The implications of urban concentrations for GDP, banking system, FDI, civic amenities, and various urban externalities (such as pollution and spatial exclusion) are also examined. It shows that India’s urban system, though it follows the rank-size rule, is huge and top-heavy. It follows also Gibrat’s law of proportionate growth. Although India’s cities collectively account for less than one third of the total population, they command more than three fourths of the country’s GDP. Megacities have become congested, clogged, polluted, and also show significant social polarization. There is a gridlock situation for the cities, inhibiting their potential for becoming effective economic and social change sites. The top-heavy character of India’s urban system also adversely impacts the balanced regional development of the country.
An Integrated Model Approach of Education for Sustainable Development: Exploring the Concepts of Water, Energy and Waste in Primary Education
Authors: Martínez-Borreguero Guadalupe , Maestre-Jiménez Jesús , Mateos-Núñez Milagros , Naranjo-Correa Francisco Luis
Published: April 2020

Education for Sustainable Development requires improving the knowledge, attitudes and behaviors of students at all levels of education. However, this should start from the earliest stages of education, promoting an effective teaching/learning process of key concepts for sustainable development. Accordingly, the general objective of this research was to analyze the concepts of water, energy and waste in the primary education curriculum (6–12 years) in Spain. A qualitative research approach was followed, with an exploratory and descriptive design. A system of categories was established for each of the concepts under study, with the aim of classifying the references found, analyzing their integration into the different subjects, academic courses, curricular elements and levels of cognitive demand required of the students. The results of the lexicographical analysis of the content reveal that the regulations governing primary education in Spain mainly focus on the concept of energy and, to a lesser extent, on the concepts of water and waste. In addition, cognitive levels of knowledge and comprehension predominate based on the taxonomy used. The results suggest the need to develop initiatives for the educational framework that promote not only learning, but also attitudes and behaviors that contribute to achieving the Sustainable Development Goals (SDGs).
A Comparative Assessment of Analytical Fate and Transport Models of Organic Contaminants in Unsaturated Soils
Authors: Stoppiello Maria Grazia , Lofrano Giusy , Carotenuto Maurizio , Viccione Giacomo , Guarnaccia Claudio , Cascini Leonardo
Published: April 2020

Analytical models for the simulation of contaminants’ fate and transport in the unsaturated zone are used in many engineering applications concerning groundwater resource management and risk assessment. As a consequence, several scientific studies dealing with the development and application of analytical solutions have been carried out. Six models have been selected and compared based on common characteristics to identify pros and cons as well as to highlight any difference in the final output. The analyzed models have been clustered into three groups according to the assumptions on contaminant source and physico-chemical mechanisms occurring during the transport. Comparative simulations were carried out with five target contaminants (Benzene, Benzo(a)pyrene, Vinyl Chloride, Trichloroethylene and Aldrin) with different decay’s coefficient, three types of soil (sand, loam and clay) and three different thicknesses of the contaminant source. The calculated concentration at a given depth in the soil for the same contamination scenario varied greatly among the models. A significant variability of the concentrations was shown due to the variation of contaminant and soil characteristics. As a general finding, the more advanced is the model, the lower the predicted concentrations; thus, models that are too simplified could lead to outcomes of some orders of magnitude greater than the advanced one.
The Influence of Mixed Reality on Satisfaction and Brand Loyalty in Cultural Heritage Attractions: A Brand Equity Perspective
Authors: Bae Sujin , Jung Timothy Hyungsoo , Moorhouse Natasha , Suh Minjeong , Kwon Ohbyung
Published: April 2020

Mixed reality technology is being increasingly used in cultural heritage attractions to enhance visitors’ experiences. However, how the characteristics of mixed reality affect satisfaction and brand loyalty has not been explored in previous research. The purpose of this study is to identify factors affecting satisfaction with mixed reality experiences at cultural and artistic visitor attractions and their influence on brand loyalty, which is connected with management performance. We propose a theoretical model based on brand equity theory in the context of mixed reality experience. Survey data were gathered from 251 respondents visiting a cultural and artistic visitor attraction in Seoul, Korea, using a stratified sampling method. Partial least squares structural equation modeling (PLS-SEM) was employed for the data analysis. The results suggest that the characteristics of mixed reality (interactivity, vividness) not only influence the affective aspects (perceived immersion, perceived enjoyment) of visitors’ experiences, but also positively affect brand awareness, brand association, and brand loyalty.
A Design-Based Learning Approach for Fostering Sustainability Competency in Engineering Education
Authors: Huang Zhiliang , Peng Annan , Yang Tongguang , Deng Shuguang , He Yuexia
Published: April 2020

This paper provides and illustrates a design-based learning (DBL) approach for fostering individual sustainability competency in engineering education. We performed two studies with engineering students in typical educational activities. The first study helped students perform a topic-specific design task in the practicum unit of a sensor technology course, which compared the performance of the DBL approach and conventional passive learning approach. The second study guided students to develop innovative projects for participating in the "Internet Plus" Innovation and Entrepreneurship Competition (IPIEC). To validate the proposed approach, stakeholder questionnaires and performance evaluations were implemented. The results show that the DBL approach was viable for sustainability competency teaching in terms of learning demand and teaching procedure. We found that students in the DBL group gave more prominence in the individual competencies, such as system-thinking, multidisciplinary applications, and collaboration. These findings suggest that applying the DBL approach to train sustainability competency in engineering education is beneficial for promoting students’ abilities in dealing with challenges involved in sustainability practice.
An Evaluation of the Impact of Hiking Tourism on the Ecological Status of Alpine Lakes—A Case Study of the Valley of Dolina Pięciu Stawów Polskich in the Tatra Mountains
Authors: Senetra Adam , Dynowski Piotr , Cieślak Iwona , Źróbek-Sokolnik Anna
Published: April 2020

Eutrophication is one of the major threats to the quality of water in high mountain lakes. The inflow of elements having biological origin may significantly aggravate the ecological status of those ecosystems. For this reason, the aim of this study was to map and assess the impact of anthropogenic pressure on alpine lakes in the valley of Dolina Pięciu Stawów Polskich (known in English as the Valley of Five Polish Lakes) in the Tatra National Park in Poland. The effects of tourism and easy access to alpine lakes on changes in their ecological status were determined. Tourist trails were evaluated based on the difficulty of access to the water surface of analyzed alpine lakes, with a method developed for assessing anthropogenic pressure on aquatic ecosystems. The method, deployed for the first time in 2019, was modified and adapted to the local environmental conditions in the research area. The results of this study indicate that tourism pressure contributes to the growth of submerged vegetation in alpine lakes. The presence of aquatic plants (including vascular plants) shows ecosystem response to water enrichment with biogenic substances. The present findings were used to formulate practical recommendations and propose modifications to the evaluated hiking trails. The research method developed in the study can support analysis and control of tourist traffic, thus reducing anthropogenic pressure on alpine lakes in national parks located in mountain areas.