bluuebunny/crossref_metadata_2025 huggingface dataset:
Polarization-Discriminated RSOA–EAM for Colorless Transmitter in WDM–PON
Authors: Zuo Chengliang , Li Xun
Published: December 2020

The integrated reflective semiconductor optical amplifier (RSOA) and electro-absorption modulator (EAM) is viewed as an appealing solution to the colorless transmitter on the optical network unit (ONU) side of wavelength-division multiplexed (WDM) passive optical networks (PONs), for its broad modulation bandwidth and high optical gain. However, the conventional RSOA–EAM usually exhibits a poor upstream signal eye-diagram because it can hardly simultaneously saturate the downstream signal and boost the upstream signal as required. By exploiting the polarization-depended RSOA gain, we propose a polarization-discriminated RSOA–EAM to improve the quality of the upstream signal eye-diagram. In this device, the transverse electric polarized downstream signal is saturated by the high gain in the RSOA active region made of compressively strained multiple quantum wells, whereas the upstream signal is linearly amplified after polarization rotation. We find that, as the quality of the upstream signal eye-diagram improves with an increased polarization rotation angle, its power drops, which indicates that there exists an optimized rotation angle to reach a compromise between the upstream signal integrity and power. Simulation results show that the dynamic extinction ratio and output power of the upstream signal can reach 8.3 dB and 11 dBm, respectively, through the proposed device with its rotation angle set at an optimum value (80°), which exceeds the specification (6 dB and 4 dBm) of the upstream transmitter as required by the next-generation PON stage two. The quality of the upstream signal eye-diagram measured in Q-factor is improved by 10 dB compared to the conventional RSOA–EAM design without polarization rotation introduced.
Anode Effect Prediction in Hall-Héroult Cells Using Time Series Characteristics
Authors: Kremser Ron , Grabowski Niclas , Düssel Roman , Mulder Albert , Tutsch Dietmar
Published: December 2020

In aluminium production, anode effects occur when the alumina content in the bath is so low that normal fused salt electrolysis cannot be maintained. This is followed by a rapid increase of pot voltage from about 4.3 V to values in the range from 10 to 80 V. As a result of a local depletion of oxide ions, the cryolite decomposes and forms climate-relevant perfluorocarbon (PFC) gases. The high pot voltage also causes a high energy input, which dissipates as heat. In order to ensure energy-efficient and climate-friendly operation, it is important to predict anode effects in advance so that they can be prevented by prophylactic actions like alumina feeding or beam downward movements. In this paper a classification model is trained with aggregated time series data from TRIMET Aluminium SE Essen (TAE) that is able to predict anode effects at least 1 min in advance. Due to a high imbalance in the class distribution of normal state and labeled anode effect state as well as possible model’s weaknesses the final F1 score of 32.4% is comparatively low. Nevertheless, the prediction provides an indication of possible anode effects and the process control system may react on it. Consequent practical implications will be discussed.
Development and Washing Reliability Testing of a Stretchable Circuit on Knit Fabric
Authors: Veske Paula , Bauwens Pieter , Bossuyt Frederick , Sterken Tom , Vanfleteren Jan
Published: December 2020

The smart textiles and wearable technology markets are expanding tirelessly, looking for efficient solutions to create long-lasting products. The research towards novel integration methods and increasing reliability of wearables and electronic textiles (e-textiles) is expanding. One obstacle to be tackled is the washability and the endurance to mechanical stresses in the washing machine. In this article, different layering of thermoplastic polyurethane (TPU) films and knit fabrics are used to integrate three different designs of stretchable copper-based meander tracks with printed circuit boards. The various combinations are washed according to the ISO 6330-2012 standard to analyze their endurance. Results suggest that one meander design withstands more washing cycles and indicate that the well-selected layer compositions increase the reliability. Higher stretchability together with greater durability is accomplished by adding an extra meander-shaped TPU film layer.
Simplified Calibration Method for Constant-Temperature Hot-Wire Anemometry
Authors: Takahashi Hidemi , Kurita Mitsuru , Iijima Hidetoshi , Koga Seigo
Published: December 2020

This study proposes a unique approach to convert a voltage signal obtained from a hot-wire anemometry to flow velocity data by making a slight modification to existing temperature-correction methods. The approach was a simplified calibration method for the constant-temperature mode of hot-wire anemometry without knowing exact wire temperature. The necessary data are the freestream temperature and a set of known velocity data which gives reference velocities in addition to the hot-wire signal. The proposed method was applied to various boundary layer velocity profiles with large temperature variations while the wire temperature was unknown. The target flow velocity was ranged between 20 and 80 m/s. By using a best-fit approach between the velocities in the boundary layer obtained by hot-wire anemometry and by the pitot-tube measurement, which provides reference data, the unknown wire temperature was sought. Results showed that the proposed simplified calibration approach was applicable to a velocity range between 20 and 80 m/s and with temperature variations up to 15 °C with an uncertainty level of 2.6% at most for the current datasets.
Modelling of the Acetification Stage in the Production of Wine Vinegar by Use of Two Serial Bioreactors
Authors: Álvarez-Cáliz Carmen M. , Santos-Dueñas Inés María , Jiménez-Hornero Jorge E. , García-García Isidoro
Published: December 2020

In the scope of a broader study about modelling wine acetification, the use of polynomial black-box models seems to be the best choice. Additionally, the use of two serially arranged bioreactors was expected to result in increased overall acetic acid productivity. This paper describes the experiments needed to obtain enough data for modelling the process and the use of second-order polynomials for this task. A fractional experimental design with central points was used with the ethanol concentrations during loading of the bioreactors, their operation temperatures, the ethanol concentrations at unloading time, and the unloaded volume in the first one as factors. Because using two serial reactors imposed some constraints on the operating ranges for the process, an exhaustive combinatorial analysis was used to identify a working combination of such ranges. The obtained models provided highly accurate predictions of the mean overall rate of acetic acid formation, the mean total production of acetic acid of the two-reactor system, and ethanol concentration at the time the second reactor is unloaded. The operational variables associated with the first bioreactor were the more strongly influential to the process, particularly the ethanol concentration at the time the first reactor was unloaded, the unloaded volume, and the ethanol concentration when loading.
Development and Preliminary Trajectory Verification of the Electromotor-Driven Parallel External Fixator for Deformity Correction
Authors: Li Guotong , Li Jianfeng , Dong Mingjie , Zuo Shiping
Published: December 2020

External fixators are widely used in deformity correction based on distraction osteogenesis. Traditionally, the rods are manually operated by patients several times a day, which will ensure the patient’s compliance, accumulative adjustment error, and trajectory deviation. To reduce the patients’ compliance and the complexity of adjustment, an electromotor-driven parallel external fixator is developed to gradually correct the deformity, which allows the fixator to be automatically adjusted and can correct any three-dimensional deformity with continuous stability. Two adjustment strategies are proposed through different trajectory control methods based on the inverse kinematics solution, and the trajectory and bone shape are generated to investigate the characteristics of the new bone more intuitively. The range of motion is performed utilizing the numerical searching method to assess the fixator’s correction capability. Finally, the trajectory verification experiment is carried out using the artificial bone model to perform the two adjustment strategies. The results show that the developed external fixator has high correction accuracy with 0.0172 mm, and can accurately and safely realize the preset correction trajectory. The developed fixator system can also be used as a teaching tool for medical training for clinicians to learn deformity correction technology.
Long-Term Prognosis of Peri-Implantitis Treatment: A Systematic Review of Prospective Trials with More Than 3 Years of Follow-Up
Authors: Di Gianfilippo Riccardo , Sirinirund Benyapha , Rodriguez Maria Vera , Chen Zhaozhao , Wang Hom-Lay
Published: December 2020

A multitude of clinical trials have tested therapeutic approaches to treat peri-implantitis but there is still no consensus on what treatment modality leads to the most favorable clinical improvement and reduced implant loss. Therefore, the present systematic review reported on the long-term clinical and radiological outcomes after treatment of peri-implantitis with different surgical approaches. A PICO question was defined; manual and electronic searches were completed to screen for human prospective studies with at least 3 years of follow-up after surgical treatment of peri-implantitis. Analyses were performed using a random-effect model. Thirteen trials reported on 706 implants and 399 patients. Open flap, resective and reconstructive approaches led to a probing depth reduction of 2.23, 2.25 and 3.78 mm with a survival rate of 84%, 90% and 95%, respectively. Reconstructive treatments were followed by an average of 2.34 mm of radiographic bone gain, flap had negligible bone changes (0.11 mm) and resective approaches resulted in a mean bone loss of 0.5 mm. Large heterogeneity existed among studies for diagnostic criteria and decontamination modalities. Within the existing limitations, regenerative approaches for the treatment of peri-implantitis lead to advantageous long-term improvement of peri-implant tissues and higher implant survival rate.
Cooperative Frequency Control of a Small-Scale Power System between Diesel Engine Driven Adjustable Speed Generator and Battery
Authors: Takahashi Rion , Umemura Atsushi , Tamura Junji
Published: December 2020

This paper proposes the application of an adjustable speed diesel engine-driven power plant employing a doubly-fed induction generator to an isolated small-scale power system including renewable power sources. This type of power plant can contribute to fast and flexible power balancing regulation under vacillating power supply such as wind, solar and other renewable power sources. Installation of a battery system is also considered, which can assist in coordinating the power plant to augment renewable power sources in the isolated power system.
From Electricity and Water Consumption Data to Information on Office Occupancy: A Supervised and Unsupervised Data Mining Approach
Authors: Stjelja Davor , Jokisalo Juha , Kosonen Risto
Published: December 2020

Climate change and technological development are pushing buildings to become more sophisticated. The installation of modern building automation systems, smart meters, and IoT devices is increasing the amount of available building operational data. The common term for this kind of building is a smart building but producing large amounts of raw data does not automatically offer intelligence that would offer new insights to the building’s operation. Smart meters are mainly used only for tracking the energy or water consumption in the building. On the other hand, building occupancy is usually not monitored in the building at all, even though it is one of the main influencing factors of consumption and indoor climate parameters. This paper is bringing the true smart building closer to practice by using machine learning methods with sub-metered electricity and water consumptions to predict the building occupancy. In the first approach, the number of occupants was predicted in an office floor using a supervised data mining method Random Forest. The model performed the best with the use of all predictors available, while from individual predictors, the sub-metered electricity used for office equipment showed the best performance. Since the supervised approach requires the continuous long-term collection of ground truth reference data (between one to three months, by this study), an unsupervised data mining method k-means clustering was tested in the second approach. With the unsupervised method, this study was able to predict the level of occupancy in a day as zero, medium, or high in a case study office floor using the equipment electricity consumption.
Determination of Major Endogenous FAHFAs in Healthy Human Circulation: The Correlations with Several Circulating Cardiovascular-Related Biomarkers and Anti-Inflammatory Effects on RAW 264.7 Cells
Authors: Dongoran Rachmad Anres , Lin Tsung-Jen , Byekyet Akhsholphan , Tang Sheau-Chung , Yang Jen-Hung , Liu Chin-Hung
Published: December 2020

Fatty acid esters of hydroxy fatty acids (FAHFAs) are newly discovered long-chain fatty acids. However, the major endogenous FAHFAs in healthy human circulation, their correlation with cardiovascular (CV) biomarkers, and their anti-inflammatory effects have not been investigated and remain unclear. In the present study, a total of 57 healthy subjects were recruited. Liquid chromatography–mass spectrometry (LC-MS) was developed for the simultaneous determination of seven FAHFAs, four long-chain fatty acids, and four non-traditional circulating CV-related biomarkers. We found two major types of FAHFAs in healthy human circulation, palmitoleic acid ester of 9-hydroxystearic acid (9-POHSA), and oleic acid ester of 9-hydroxystearic acid (9-OAHSA). Both 9-POHSA and 9-OAHSA had a strong positive correlation with each other and were negatively correlated with fasting blood glucose, S-adenosyl-l-homocysteine (SAH), and trimethylamine N-oxide (TMAO), but not with l-homocysteine. 9-POHSA was also positively correlated with l-carnitine. Moreover, we confirmed that both 9-POHSA and 9-OAHSA exhibited an anti-inflammatory effect by suppressing LPS stimulated cytokines, including IL-1β and IL-6 in RAW 264.7 cells. In addition, palmitoleic acid also had a positive correlation with 9-POHSA and 9-OAHSA. As far as we know, this is the first report showing the major endogenous FAHFAs in healthy subjects and their CV protection potential which might be correlated with SAH and TMAO reduction, l-Carnitine elevation, and their anti-inflammatory effects.
HDL-Mediated Cholesterol Efflux and Plasma Loading Capacities Are Altered in Subjects with Metabolically- but Not Genetically Driven Non-Alcoholic Fatty Liver Disease (NAFLD)
Authors: Di Costanzo Alessia , Ronca Annalisa , D’Erasmo Laura , Manfredini Matteo , Baratta Francesco , Pastori Daniele , Di Martino Michele , Ceci Fabrizio , Angelico Francesco , Del Ben Maria , Pavanello Chiara , Turri Marta , Calabresi Laura , Favari Elda , Arca Marcello
Published: December 2020

Background. Non-alcoholic fatty liver disease (NAFLD) increases the risk of atherosclerosis but this risk may differ between metabolically- vs. genetically-driven NAFLD. High-density lipoprotein (HDL)-mediated cholesterol efflux (CEC) and plasma loading capacity (CLC) are key factors in atherogenesis. Aims. To test whether CEC and CLC differ between metabolically- vs. genetically-determined NAFLD. Methods: CEC and CLC were measured in 19 patients with metabolic NAFLD and wild-type PNPLA3 genotype (Group M), 10 patients with genetic NAFLD carrying M148M PNPLA3 genotype (Group G), and 10 controls PNPLA3 wild-types and without NAFLD. CEC and CLC were measured ex vivo by isotopic and fluorimetric techniques using cellular models. Results: Compared with Group G, Group M showed reduced total CEC (−18.6%; p < 0.001) as well as that mediated by cholesterol transporters (−25.3% ABCA1; −16.3% ABCG1; −14.8% aqueous diffusion; all p < 0.04). No difference in CEC was found between Group G and controls. The presence of metabolic syndrome further impaired ABCG1-mediated CEC in Group M. Group M had higher plasma-induced CLC than Group G and controls (p < 0.001). Conclusions: Metabolically-, but not genetically-, driven NAFLD associates with dysfunctional HDL-meditated CEC and abnormal CLC. These data suggest that the mechanisms of anti-atherogenic protection in metabolic NAFLD are impaired.
Review of Integrated Optical Biosensors for Point-of-Care Applications
Authors: Chen Yung-Tsan , Lee Ya-Chu , Lai Yao-Hsuan , Lim Jin-Chun , Huang Nien-Tsu , Lin Chih-Ting , Huang Jian-Jang
Published: December 2020

This article reviews optical biosensors and their integration with microfluidic channels. The integrated biosensors have the advantages of higher accuracy and sensitivity because they can simultaneously monitor two or more parameters. They can further incorporate many functionalities such as electrical control and signal readout monolithically in a single semiconductor chip, making them ideal candidates for point-of-care testing. In this article, we discuss the applications by specifically looking into point-of-care testing (POCT) using integrated optical sensors. The requirement and future perspective of integrated optical biosensors for POC is addressed.
Highly Sensitive Detection of CA 125 Protein with the Use of an n-Type Nanowire Biosensor
Authors: Malsagova Kristina A. , Pleshakova Tatyana O. , Galiullin Rafael A. , Kozlov Andrey F. , Shumov Ivan D. , Popov Vladimir P. , Tikhonenko Fedor V. , Glukhov Alexander V. , Ziborov Vadim S. , Petrov Oleg F. , Fortov Vladimir E. , Archakov Alexander I. , Ivanov Yuri D.
Published: December 2020

The detection of CA 125 protein in a solution using a silicon-on-insulator (SOI)-nanowire biosensor with n-type chip has been experimentally demonstrated. The surface of nanowires was modified by covalent immobilization of antibodies against CA 125 in order to provide the biospecificity of the target protein detection. We have demonstrated that the biosensor signal, which results from the biospecific interaction between CA 125 and the covalently immobilized antibodies, increases with the increase in the protein concentration. At that, the minimum concentration, at which the target protein was detectable with the SOI-nanowire biosensor, amounted to 1.5 × 10−16 M.
Navigated TMS in the ICU: Introducing Motor Mapping to the Critical Care Setting
Authors: Schramm Severin , Haddad Alexander F. , Chyall Lawrence , Krieg Sandro M. , Sollmann Nico , Tarapore Phiroz E.
Published: December 2020

Navigated transcranial magnetic stimulation (nTMS) is a modality for noninvasive cortical mapping. Specifically, nTMS motor mapping is an objective measure of motor function, offering quantitative diagnostic information regardless of subject cooperation or consciousness. Thus far, it has mostly been restricted to the outpatient setting. This study evaluates the feasibility of nTMS motor mapping in the intensive care unit (ICU) setting and solves the challenges encountered in this special environment. We compared neuronavigation based on computed tomography (CT) and magnetic resonance imaging (MRI). We performed motor mappings in neurocritical patients under varying conditions (e.g., sedation or hemicraniectomy). Furthermore, we identified ways of minimizing electromyography (EMG) noise in the interference-rich ICU environment. Motor mapping was performed in 21 patients (six females, median age: 69 years). In 18 patients, motor evoked potentials (MEPs) were obtained. In three patients, MEPs could not be evoked. No adverse reactions occurred. We found CT to offer a comparable neuronavigation to MRI (CT maximum e-field 52 ± 14 V/m vs. MRI maximum e-field 52 ± 11 V/m; p = 0.6574). We detailed EMG noise reduction methods and found that propofol sedation of up to 80 mcg/kg/h did not inhibit MEPs. Yet, nTMS equipment interfered with exposed pulse oximetry. nTMS motor mapping application and use was illustrated in three clinical cases. In conclusion, we present an approach for the safe and reliable use of nTMS motor mapping in the ICU setting and outline possible benefits. Our findings support further studies regarding the clinical value of nTMS in critical care settings.
Interest in Genetic Feedback for Alcohol Use Disorder and Related Substance Use and Psychiatric Outcomes among Young Adults
Authors: Driver Morgan , Kuo Sally , Dick Danielle ,   on behalf of the Spit for Science Working Group
Published: December 2020

An exponential growing number of individuals are accessing genetic risk information via direct to consumer companies. Alcohol dependence is the third most accessed genetic risk score on a publicly available direct to consumer website. Better understanding of the degree to which individuals are interested in receiving personalized genetic feedback, the factors that relate to interest, and genetic knowledge will be critical to lay the foundation for precision medicine initiatives, especially for substance use and psychiatric outcomes, where less is known. To assess interest in receiving genetic feedback for alcohol use disorder (AUD) and understanding of genetic concepts related to psychiatric conditions, we conducted a survey with participants recruited from a registry that enrolled incoming cohorts of freshmen at an urban public university; 205 participants (76.5% female; 58.9% self-reported as White; Mage = 24.48 years) completed the survey. Results indicated that participants are highly interested in receiving genetic feedback for AUD (79.0%) but there is a lack of understanding of complex genetic concepts in a sizable proportion of the sample (25.4%). Additional research is needed to assess how to address this lack of knowledge before genetic feedback for AUD can be returned in a way that benefits the individual.
Focality of the Induced E-Field Is a Contributing Factor in the Choice of TMS Parameters: Evidence from a 3D Computational Model of the Human Brain
Authors: Konakanchi Deepika , de Jongh Curry Amy L. , Waters Robert S. , Narayana Shalini
Published: December 2020

Transcranial magnetic stimulation (TMS) is a promising, non-invasive approach in the diagnosis and treatment of several neurological conditions. However, the specific results in the cortex of the magnitude and spatial distribution of the secondary electrical field (E-field) resulting from TMS at different stimulation sites/orientations and varied TMS parameters are not clearly understood. The objective of this study is to identify the impact of TMS stimulation site and coil orientation on the induced E-field, including spatial distribution and the volume of activation in the cortex across brain areas, and hence demonstrate the need for customized optimization, using a three-dimensional finite element model (FEM). A considerable difference was noted in E-field values and distribution at different brain areas. We observed that the volume of activated cortex varied from 3000 to 7000 mm3 between the selected nine clinically relevant coil locations. Coil orientation also changed the induced E-field by a maximum of 10%, and we noted the least optimal values at the standard coil orientation pointing to the nose. The volume of gray matter activated varied by 10% on average between stimulation sites in homologous brain areas in the two hemispheres of the brain. This FEM simulation model clearly demonstrates the importance of TMS parameters for optimal results in clinically relevant brain areas. The results show that TMS parameters cannot be interchangeably used between individuals, hemispheres, and brain areas. The focality of the TMS induced E-field along with its optimal magnitude should be considered as critical TMS parameters that should be individually optimized.
HLA Class II Genotype Does Not Affect the Myelin Responsiveness of Multiple Sclerosis Patients
Authors: Derdelinckx Judith , Nkansah Irene , Ooms Naomi , Van Bruggen Laura , Emonds Marie-Paule , Daniëls Liesbeth , Reynders Tatjana , Willekens Barbara , Cras Patrick , Berneman Zwi N. , Cools Nathalie
Published: December 2020

Background: When aiming to restore myelin tolerance using antigen-specific treatment approaches in MS, the wide variety of myelin-derived antigens towards which immune responses are targeted in multiple sclerosis (MS) patients needs to be taken into account. Uncertainty remains as to whether the myelin reactivity pattern of a specific MS patient can be predicted based upon the human leukocyte antigen (HLA) class II haplotype of the patient. Methods: In this study, we analyzed the reactivity towards myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP) and proteolipid protein (PLP) peptides using direct interferon (IFN)-γ enzyme-linked immune absorbent spot (ELISPOT). Next, the HLA class II haplotype profile was determined by next-generation sequencing. In doing so, we aimed to evaluate the possible association between the precursor frequency of myelin-reactive T cells and the HLA haplotype. Results: Reactivity towards any of the analyzed peptides could be demonstrated in 65.0% (13/20) of MS patients and in 60.0% (6/10) of healthy controls. At least one of the MS risk alleles HLA-DRB1*15:01, HLA-DQA1*01:02 and HLA-DQB1*06:02 was found in 70.0% (14/20) of patients and in 20.0% (2/10) of healthy controls. No difference in the presence of a myelin-specific response, nor in the frequency of myelin peptide-reactive precursor cells could be detected among carriers and non-carriers of these risk alleles. Conclusion: No association between HLA haplotype and myelin reactivity profile was present in our study population. This complicates the development of antigen-specific treatment approaches and implies the need for multi-epitope targeting in an HLA-unrestricted manner to fully address the wide variation in myelin responses and HLA profiles in a heterogeneous group of MS patients.
The Effects of Transition Metal Oxides (Me = Ti, Zr, Nb, and Ta) on the Mechanical Properties and Interfaces of B4C Ceramics Fabricated via Pressureless Sintering
Authors: Liu Guanqi , Chen Shixing , Zhao Yanwei , Fu Yudong , Wang Yujin
Published: December 2020

There is little available research on how different transition metal oxides influence the behavior of B4C-based ceramics, especially for Ta2O5 and Nb2O5. B4C-MeB2 (Me = Ti, Zr, Nb, and Ta) multiphase ceramic samples were prepared via in situ pressureless sintering at 2250 °C, involving the mixing of B4C and MeOx powders, namely TiO2, ZrO2, Nb2O5, and Ta2O5. The phase constituents, microstructures, and mechanical properties of the samples were tested. The results indicated that different transition metal elements had different effects on the ceramic matrix, as verified through a comparative analysis. Additionally, the doped WC impurity during the ball milling process led to the production of (Me, W)B2 and W2B5, which brought about changes in morphology and performance. In this study, the Ta2O5-added sample exhibited the best performance, with elastic modulus, flexural strength, Vickers hardness, and fracture toughness values of 312.0 GPa, 16.3 GPa, 313.0 MPa, and 6.08 MPa·m1/2, respectively. The comprehensive mechanical properties were better than the reported values when the mass fraction of the second phase was around five percent.
Modified Epoxy with Chitosan Triazine Dihydrazide Derivatives for Mechanical and Corrosion Protection of Steel
Authors: Atta Ayman M. , El-Faham Ayman , Al-Lohedan Hamad A. , Ezzat Abdelrahman O.
Published: December 2020

Modification of the curing exothermic reaction of epoxy resin with polyamine (PA) hardeners by new chemically bonded fillers to improve the mechanical properties and anticorrosion performances of the epoxy coatings is the main goal for wide applications of epoxy coatings. In this work, the chemical structure of chitosan was modified with triazine hydrazide moiety that contains primary, secondary, and tertiary amine groups to act as activator and dangling chain linkers during the curing of epoxy/PA system. Different molecular masses of chitosan were modified with triazine dihydrazide moiety (Ch-TH2), and their chemical structures and surface morphologies were identified. Their thermal stabilities were investigated, and the grafting percentages with triazine hydrazide were determined from thermal analysis. Different weight percentages of Ch-TH2 ranged from 1 to 10 Wt. % were added to the epoxy/PA system, and their curing characteristics, such as heat enthalpy and glass transition temperature, were determined from non-isothermal dynamic scanning calorimetric thermograms. The effects of molecular masses, triazine dihydrazide %, and Ch-TH2 Wt. % on the mechanical, adhesion and anticorrosive properties of the cured epoxy/PA coatings for steel were investigated. The optimum Ch-TH2 Wt. % was selected from 3 to 6 Wt. % to improve the mechanical, adhesion, and anticorrosive properties of the cured epoxy/PA coatings.
Durable Flame-Resistant and Ultra-Hydrophobic Aramid Fabrics via Plasma-Induced Graft Polymerization
Authors: Siddig Eshraga A. A. , Zhang Yu , Yang Baojing , Wang Tianshu , Shi Jianjun , Guo Ying , Xu Yu , Zhang Jing
Published: December 2020

A durable flame-resistant and ultra-hydrophobic phosphorus–fluoride coating on aramid fabrics was achieved by plasma-induced graft polymerization. The aramid fabrics were activated and roughed through the low-pressure plasma firstly, which involves the sequential coating of a mixture of phosphorus–fluoride emulsion copolymer. When potentially exposed to flame or water, such a surface produces a dual effect in which it is intumescent and waterproof, successfully giving the coated fabrics flame-resistant ultra-hydrophobic bifunctional properties. Thus, adhesive coatings provide a convenient way to resolve the issue of washing durability of the coatings. The as-prepared fabrics last for 10 repeatable washing cycles without losing their flame resistance and superhydrophobicity, suggesting future applications as advanced multifunctional textiles. Compared to an untreated coating, its char length was less than 1 cm with no measurable after-flame or after-glow times, and its static water contact angle remained stable above 170°. Meanwhile, the control sample was unable to extinguish the fire with a damage length of 10.6 cm and a water contact angle of 100°. All the results indicate that plasma-reactive polar groups interact between phosphorus and fluorine elements, leading to an increased relative atom ratio P and F through Energy-Dispersive Spectrometer (EDS) spectra and XPS analysis, which inhibits the flammability and wettability.
Properties of Barium Cerate Thin Films Formed Using E-Beam Deposition
Authors: Campos Covarrubias Monica Susana , Sriubas Mantas , Bockute Kristina , Winiarz Piotr , Miruszewski Tadeusz , Skubida Wojciech , Jaworski Daniel , Bartmański Michał , Szkodo Marek , Gazda Maria , Laukaitis Giedrius
Published: December 2020

This article focuses on the properties of the BaCeO3 thin films formed by electron-beam vapor deposition and investigates the formation of barium cerates on supports with different thermal expansion coefficients (Stainless Steel, Invar, Glass Sealing, and Inconel substrates) and the influence of the technological parameters on the properties of the formed thin films with an emphasis on the stability of the films. Morphology and phase composition and mechanical and electrical properties were investigated. It was found that the main factors influencing the phase composition and morphology of the films are the temperature of the support and the deposition rate. However, the mechanical properties of the films are mostly influenced by strains introduced to thin films by using different supports. Two interesting features of the electrical properties of the studied strained films were noticed: the film with the highest in-plane tensile strain showed the lowest activation energy of total conductivity, whereas the film with the lowest strain showed the highest value of total conductivity.
Microstructure and Material Properties of Ti-15mass%Nb Alloy after Gas Nitriding and Quenching Process
Authors: Mantani Yoshikazu , Shimada Kentaro , Eguchi Naoki
Published: December 2020

The α′ martensite of Ti-15mass%Nb alloy exhibits high internal friction with high damping properties. However, its structure is smoother than the α + β structure. Therefore, a hardened surface layer is required for abrasion resistance. This study fabricated a martensite structure inside the nitriding layer by quenching, after gas nitriding at 1023 and 1223 K. Vickers hardness test, X-ray diffraction, scanning electron microscopy (SEM), and SEM-energy dispersive X-ray (SEM-EDX) measurements from the surface to the inside were made after the heat treatment process. In addition, the Young’s modulus and internal friction were calculated from the damping analysis. The α-TiN0.3 and β phase region was formed at approximately 80 µm from the surface at 1023 and 1223 K, and it was hardened. The internal friction of the gas nitriding and quenching specimens at 1023 and 1223 K was relatively high, though it did not reach that of the as-quenched specimen owing to the influence of the surface structure. From these results, it is considered that these material property values of the alloy can be controlled using the nitriding and quenching processes.
Teachers’ Perspectives on the Intertwining of Tangible and Digital Modes of Activity with a Drawing Robot for Geometry
Authors: Baccaglini-Frank Anna E. , Santi George , Del Zozzo Agnese , Frank Eric
Published: December 2020

The GeomBot is a drawing robot that combines the well-known strengths and opportunities offered by Scratch with those of Papert’s original robotic drawing-turtle. In this study we look at the GeomBot as a physical programmable artifact around which action research with a group of teachers and a researcher was carried out with the aim of designing, implementing and discussing geometry activities for primary school classes. The aim of this article is to investigate teachers’ positioning and perspectives with respect to the activities and the educational environment emerging around the Geombot in the action research. The action research meetings between September 2018 and June 2019 included nine primary school teachers from seven different Italian schools, who met regularly with the first author. After the design and experimentation sessions, in June 2019, the teachers shared their experiences during a final meeting and group discussion guided by the first author. The data collected from the teachers were analyzed using cultural categories from the Semiotic Systems of Cultural Signification, theorized by the Theory of Objectification, to identify the most significant features defining the teachers’ perspectives and identity. The seven emergent features cover teachers’ positioning with respect to: forms of rationality and language and languages: sensuous cognition and the use of ideal and material semiotic resources; accepted teaching practices, problems and situations; mathematical knowledge; the conception of the student; social interaction and forms of rationality; ethical issues; technology.
Use of Mobile Applications in Developing Reading Comprehension in Second Language Acquisition—A Review Study
Authors: Klimova Blanka , Zamborova Katarina
Published: December 2020

Reading is a fundamental skill for academic success because university students need to comprehend an extensive amount of information in a short time to achieve their academic goals. However, the influx of new technologies into education has challenged the teaching of reading skills in a foreign language. The purpose of this study was to explore the effect of emerging technologies, especially mobile applications, on second language reading comprehension in the period between 1 January and 30 September 2020. Therefore, the authors of this article conducted a search of available studies on the topic, i.e., the use of mobile applications in developing reading comprehension in second language acquisition, in two databases: Web of Science and Scopus. Despite the methodological differences, the findings of all of the identified studies showed that there was an improvement in reading comprehension after the treatment with mobile applications. In addition, a positive attitude and enhanced learner motivation when using mobile apps was found in several studies. Overall, there is potential for developing research on MALL and reading comprehension for randomized control studies with larger populations and longer intervention periods.
A Novel Motion Intention Recognition Approach for Soft Exoskeleton via IMU
Authors: Zhu Lu , Wang Zhuo , Ning Zhigang , Zhang Yu , Liu Yida , Cao Wujing , Wu Xinyu , Chen Chunjie
Published: December 2020

To solve the complexity of the traditional motion intention recognition method using a multi-mode sensor signal and the lag of the recognition process, in this paper, an inertial sensor-based motion intention recognition method for a soft exoskeleton is proposed. Compared with traditional motion recognition, in addition to the classic five kinds of terrain, the recognition of transformed terrain is also added. In the mode acquisition, the sensors’ data in the thigh and calf in different motion modes are collected. After a series of data preprocessing, such as data filtering and normalization, the sliding window is used to enhance the data, so that each frame of inertial measurement unit (IMU) data keeps the last half of the previous frame’s historical information. Finally, we designed a deep convolution neural network which can learn to extract discriminant features from temporal gait period to classify different terrain. The experimental results show that the proposed method can recognize the pose of the soft exoskeleton in different terrain, including walking on flat ground, going up and downstairs, and up and down slopes. The recognition accuracy rate can reach 97.64%. In addition, the recognition delay of the conversion pattern, which is converted between the five modes, only accounts for 23.97% of a gait cycle. Finally, the oxygen consumption was measured by the wearable metabolic system (COSMED K5, The Metabolic Company, Rome, Italy), and compared with that without an identification method; the net metabolism was reduced by 5.79%. The method in this paper can greatly improve the control performance of the flexible lower extremity exoskeleton system and realize the natural and seamless state switching of the exoskeleton between multiple motion modes according to the human motion intention.
On Dynamics of a Fractional-Order Discrete System with Only One Nonlinear Term and without Fixed Points
Authors: Khennaoui Amina-Aicha , Ouannas Adel , Momani Shaher , Batiha Iqbal M. , Dibi Zohir , Grassi Giuseppe
Published: December 2020

Dynamical systems described by fractional-order difference equations have only been recently introduced inthe literature. Referring to chaotic phenomena, the type of the so-called “self-excited attractors” has been so far highlighted among different types of attractors by several recently presented fractional-order discrete systems. Quite the opposite, the type of the so-called “hidden attractors”, which can be characteristically revealed through exploring the same aforementioned systems, is almost unexplored in the literature. In view of those considerations, the present work proposes a novel 3D chaotic discrete system able to generate hidden attractors for some fractional-order values formulated for difference equations. The map, which is characterized by the absence of fixed points, contains only one nonlinear term in its dynamic equations. An appearance of hidden attractors in their chaotic modes is confirmed through performing some computations related to the 0–1 test, largest Lyapunov exponent, approximate entropy, and the bifurcation diagrams. Finally, a new robust control law of one-dimension is conceived for stabilizing the newly established 3D fractional-order discrete system.
Max-Min Fairness and Sum Throughput Maximization for In-Band Full-Duplex IoT Networks: User Grouping, Bandwidth and Power Allocation
Authors: Khanh Ngo Tan Vu , Nguyen Van Dinh
Published: December 2020

The skyrocketing growth in the number of Internet of Things (IoT) devices has posed a huge traffic demand for fifth-generation (5G) wireless networks and beyond. In-band full-duplex (IBFD), which is theoretically expected to double the spectral efficiency of a half-duplex wireless channel and connect more devices, has been considered as a promising technology in order to accelerate the development of IoT. In order to exploit the full potential of IBFD, the key challenge is how to handle network interference (including self-interference, co-channel interference, and multiuser interference) more effectively. In this paper, we propose a simple yet efficient user grouping method, where a base station (BS) serves strong downlink users and weak uplink users and vice versa in different frequency bands, mitigating severe network interference. First, we aim to maximize a minimum rate among all of the users subject to bandwidth and power constraints, which is formulated as a nonconvex optimization problem. By leveraging the inner approximation framework, we develop a very efficient iterative algorithm for solving this problem, which guarantees at least a local optimal solution. The proposed iterative algorithm solves a simple convex program at each iteration, which can be further cast to a conic quadratic program. We then formulate the optimization problem of sum throughput maximization, which can be solved by the proposed algorithm after some slight modifications. Extensive numerical results are provided to show not only the benefit of using full-duplex radio at BS, but also the advantage of the proposed user grouping method.
Priority Determination to Apply Artificial Intelligence Technology in Military Intelligence Areas
Authors: Cho Sungrim , Shin Woochang , Kim Neunghoe , Jeong Jongwook , In Hoh Peter
Published: December 2020

The Ministry of National Defense of South Korea is currently acquiring various surveillance and reconnaissance assets to improve its independent surveillance and reconnaissance capabilities. With the deployment of new strategic and tactical surveillance and reconnaissance assets, the amount of information collected will increase significantly, and military intelligence capable of handling greater complexity will be needed to process such information. As a consequence, it will no longer be possible to handle the increased workload through a manual analysis conducted by intelligence analysists. Further, the number of intelligence analysists is expected to decrease in the near future owing to a reduction in the total number of troops, thereby exacerbating the need to apply artificial intelligence technology to process military intelligence tasks more quickly and accurately. In this study, a method is introduced for determining the ways to prioritize the AI technology domains applied to military intelligence. Consequently, among the five stages used, the processing stage has the highest priority. The application of AI technology to all the stages of information circulation may be ideal. Nevertheless, among various military intelligence domains, the one that affords the highest effectiveness of such an application should be prioritized. This is owing to resource and defense budget limitations.
An Approach of Feed-Forward Neural Network Throughput-Optimized Implementation in FPGA
Authors: Novickis Rihards , Justs Daniels Jānis , Ozols Kaspars , Greitāns Modris
Published: December 2020

Artificial Neural Networks (ANNs) have become an accepted approach for a wide range of challenges. Meanwhile, the advancement of chip manufacturing processes is approaching saturation which calls for new computing solutions. This work presents a novel approach of an FPGA-based accelerator development for fully connected feed-forward neural networks (FFNNs). A specialized tool was developed to facilitate different implementations, which splits FFNN into elementary layers, allocates computational resources and generates high-level C++ description for high-level synthesis (HLS) tools. Various topologies are implemented and benchmarked, and a comparison with related work is provided. The proposed methodology is applied for the implementation of high-throughput virtual sensor.
Synthesis, Crystal Structure, and Ionic Conductivity of MgAl2-xGaxCl8 and MgGa2Cl7Br
Authors: Tomita Yasumasa , Saito Ryo , Nagata Ayaka , Yamane Yohei , Kohno Yoshiumi
Published: December 2020

MgAl2-xGaxCl8 and MgGa2Cl7Br was synthesized from MgCl2, MgBr2, AlCl3, and GaCl3, and the physical properties were evaluated by XRD, AC conductivity, and X-ray fluorescence. MgAl2-xGaxCl8 has the same crystal structure as MgAl2Cl8, belongs to the space group C2/c, and forms a solid solution in all the synthesized compositions. We attempted to MgGa2Cl8-yBry synthesize in the same manner as MgAl2Cl8, but only obtained MgGa2Cl7Br as a single-phase compound. The AC conductivity of MgAl2-xGaxCl8 was lowest for MgAl2Cl8 and highest for MgGa2Cl8. The conductivity of MgGa2Cl8 at 400 K was 1.7 × 10−6 S/cm. The conductivity of MgGa2Cl7Br was higher than that of MgAl2-xGaxCl8 with a value of 1.6 × 10−5 S/cm at 400 K. The formation of Mg metal was observed at the surface of the cathode electrode in an experiment of flowing a direct current using an electrochemical cell, indicating that this compound is a magnesium ion conductor.
Poplar Short Rotation Coppice Plantations under Mediterranean Conditions: The Case of Spain
Authors: Oliveira Nerea , Pérez-Cruzado César , Cañellas Isabel , Rodríguez-Soalleiro Roque , Sixto Hortensia
Published: December 2020

Developing a circular bioeconomy based on the sustainable use of biological resources, such as biomass, seems to be the best way of responding to the challenges associated with global change. Among the many sources, short rotation forest crops are an essential instrument for obtaining quality biomass with a predictable periodicity and yield, according to the areas of cultivation. This review aims to provide an overview of available knowledge on short rotation coppice Populus spp. plantations under Mediterranean conditions and specifically in Spain, in order to identify not only the status, but also the future prospects, for this type of biomass production. The analysis of available information was conducted by taking into consideration the following aspects: Genetic plant material; plantation design, including densities, rotation lengths and the number of rotations, and mixtures; management activities, including irrigation, fertilization, and weed control; yield prediction; biomass characterization; and finally, an evaluation of the sustainability of the plantation and ecosystem services provided. Despite advances, there is still much to be done if these plantations are to become a commercial reality in some Mediterranean areas. To achieve this aim, different aspects need to be reconsidered, such as irrigation, bearing in mind that water restrictions represent a real threat; the specific adaptation of genetic material to these conditions, in order to obtain a greater efficiency in resource use, as well as a greater resistance to pests and diseases or tolerance to abiotic stresses such as drought and salinity; rationalizing fertilization; quantifying and valuing the ecosystem services; the advance of more reliable predictive models based on ecophysiology; the specific characterization of biomass for its final use (bioenergy/bioproducts); technological improvements in management and harvesting; and finally, improving the critical aspects detected in environmental, energy, and economic analyses to achieve profitable and sustainable plantations under Mediterranean conditions.