bluuebunny/crossref_metadata_2025 huggingface dataset:
Attenuation Factors in Molecular Electronics: Some Theoretical Concepts
Authors: Dappe Yannick J.
Published: September 2020

Understanding the electronic transport mechanisms in molecular junctions is of paramount importance to design molecular devices and circuits. In particular, the role of the different junction components contributing to the current decay—namely the attenuation factor—is yet to be clarified. In this short review, we discuss the main theoretical approaches to tackle this question in the non-resonant tunneling regime. We illustrate our purpose through standard symmetric junctions and through recent studies on hybrid molecular junctions using graphene electrodes. In each case, we highlight the contribution from the anchoring groups, the molecular backbone and the electrodes, respectively. In this respect, we consider different anchoring groups and asymmetric junctions. In light of these results, we discuss some perspectives to describe accurately the attenuation factors in molecular electronics.
An Overview of Methods for Cardiac Rhythm Detection in Zebrafish
Authors: Santoso Fiorency , Farhan Ali , Castillo Agnes L. , Malhotra Nemi , Saputra Ferry , Kurnia Kevin Adi , Chen Kelvin H.-C. , Huang Jong-Chin , Chen Jung-Ren , Hsiao Chung-Der
Published: September 2020

The heart is the most important muscular organ of the cardiovascular system, which pumps blood and circulates, supplying oxygen and nutrients to peripheral tissues. Zebrafish have been widely explored in cardiotoxicity research. For example, the zebrafish embryo has been used as a human heart model due to its body transparency, surviving several days without circulation, and facilitating mutant identification to recapitulate human diseases. On the other hand, adult zebrafish can exhibit the amazing regenerative heart muscle capacity, while adult mammalian hearts lack this potential. This review paper offers a brief description of the major methodologies used to detect zebrafish cardiac rhythm at both embryonic and adult stages. The dynamic pixel change method was mostly performed for the embryonic stage. Other techniques, such as kymography, laser confocal microscopy, artificial intelligence, and electrocardiography (ECG) have also been applied to study heartbeat in zebrafish embryos. Nevertheless, ECG is widely used for heartbeat detection in adult zebrafish since ECG waveforms’ similarity between zebrafish and humans is prominent. High-frequency ultrasound imaging (echocardiography) and modern electronic sensor tag also have been proposed. Despite the fact that each method has its benefits and limitations, it is proved that zebrafish have become a promising animal model for human cardiovascular disease, drug pharmaceutical, and toxicological research. Using those tools, we conclude that zebrafish behaviors as an excellent small animal model to perform real-time monitoring for the developmental heart process with transparent body appearance, to conduct the in vivo cardiovascular performance and gene function assays, as well as to perform high-throughput/high content drug screening.
Removal of Metals by Sulphide Precipitation Using Na2S and HS−-Solution
Authors: Prokkola Hanna , Nurmesniemi Emma-Tuulia , Lassi Ulla
Published: September 2020

Precipitation of metals as metal sulphides is a practical way to recover metals from mine water. Sulphide precipitation is useful since many metals are very sparingly soluble as sulphides. Precipitation is also pH dependent. This article investigates the precipitation of metals individually as sulphides and assesses which metals are precipitated as metal hydroxides by adjustment of the pH. The precipitation of different metals as sulphides was studied to determine the conditions under which the HS− solution from the sulphate reduction reaction could be used for precipitation. H2S gas and ionic HS− produced during anaerobic treatment could be recycled from the process to precipitate metals in acidic mine drainage (AMD) prior to anaerobic treatment (Biological sulphate reduction), thereby recovering several metals. Precipitation of metals with HS− was fast and produced fine precipitates. The pH of acid mine water is about 2–4, and it can be adjusted to pH 5.5 before sulphide precipitation, while the precipitation, on the other hand, requires a sulphide solution with pH at 8 and the sulphide in HS− form. This prevents H2S formation and mitigates the risk posed from the evaporation of toxic hydrogen sulphur gas. This is a lower increase than is required for hydroxide precipitation, in which pH is typically raised to approximately nine. After precipitation, metal concentrations ranged from 1 to 30 μg/L.
Linear Stochastic Models in Discrete and Continuous Time
Authors: Pollock D. Stephen G.
Published: September 2020

The econometric data to which autoregressive moving-average models are commonly applied are liable to contain elements from a limited range of frequencies. If the data do not cover the full Nyquist frequency range of [0,π] radians, then severe biases can occur in estimating their parameters. The recourse should be to reconstitute the underlying continuous data trajectory and to resample it at an appropriate lesser rate. The trajectory can be derived by associating sinc fuction kernels to the data points. This suggests a model for the underlying processes. The paper describes frequency-limited linear stochastic differential equations that conform to such a model, and it compares them with equations of a model that is assumed to be driven by a white-noise process of unbounded frequencies. The means of estimating models of both varieties are described.
Evaluation of the Administrative Phase-Out of Coal Power Plants on the Italian Electricity Market
Authors: Fiorelli Michele , Keles Dogan , Montana Francesco , Restifo Giovanni Lorenzo , Riva Sanseverino Eleonora , Zizzo Gaetano
Published: September 2020

Although decarbonisation is one of the most important macro-trends of this century, electricity generation from coal power plants is still broadly common. The main goal of this study is to evaluate the impact of a premature coal power plants phase-out on the Italian day-ahead electricity market. For this purpose, two electricity price forecasts, related to different scenarios between 2019 and 2030, and two different hypotheses for the creation of electricity spot price, were compared. The results from the different scenarios show that coal power plants phase-out determines a small variation in electricity price when bid-up is not considered; instead, when operators’ bid-up is included in the study, the price variation becomes relevant.
Heterogenic Autotuner for Electro-Pneumatic Single-Action Actuators
Authors: Bartyś Michał
Published: September 2020

The main concept is to design the novel autotuner in a way that it will introduce benefits that arise from the effect of the fusion of the quantitative and qualitative knowledge gained from identification experiments, long-time expertise, and theoretical findings. The novelty of this approach is in the manner in which the expert heuristic knowledge is used for the development of an easy-to-use and time-efficient tuning process. In the proposed approach, the positioner simply learns, mimics, and follows up the tuning process that is performed by an experienced human operator. The major strength of this approach is that all parameters of positioner PID controller can be estimated by only identifying one single parameter that is the effective time constant of the pneumatic actuator. The elaborated autotuning algorithm is experimentally examined with different commercially available pneumatic actuators and control valves. The obtained results demonstrate that the proposed autotuning approach exhibits good performance, usability, and robustness. This should be considered as particularly relevant in the processes of installing, commissioning, and servicing single-action final control elements.
Nine Measures to Take—Unlocking the Potential for Biomass Heat in the German Industry and the Trade, Commerce, and Service Sector
Authors: Schmidt-Baum Torsten , Thrän Daniela
Published: September 2020

Solid biofuels have the potential of making a major contribution to achieving the objectives of the Paris Climate Agreement if they are used more extensively for covering the heat demand of the industry and the trade, commerce, and service (TCS) sector. To unlock this potential, a holistic analysis of the supply chain from producer to end customer was performed, involving consultants, planners, and financial institutions. The focus is on the deployment of larger biomass heating boilers (with heat loads spanning several 100 kW to several MW). The study identifies the most important barriers for expanding the use of solid biofuels for heat in the German TCS sector as well as in the industry sector. Nine sets of measures were identified for overcoming the most critical barriers, among others, by drawing on best practice approaches and solutions from other German and European contexts. Based on these measures, political recommendations were derived to shape the regulatory framework conditions accordingly. These recommendations can in turn offer a stimulus for other countries to foster a more efficient and climate-effective use of biomass.
Hierarchical Manganese–Iron-Layered Double Hydroxide Nanosheets for Asymmetric Supercapacitors
Authors: Patil Dipali S. , Pawar Sachin A. , Kim Hyo Jin , Shin Jae Cheol
Published: September 2020

This work presents a synthesis of hierarchical manganese–iron-layered double hydroxide (MnFe-LDH) nanostructured electrodes using the hydrothermal synthesis route by varying the reaction time for electrochemical energy storage applications. The electrochemical behavior of the MnFe-LDH electrodes synthesized at different reaction times was analyzed in a three-electrode cell configuration using 2 M KOH electrolyte. The uniform and well-organized MnFe-LDH nanosheet electrode (MnFe-12h) showed the maximum areal capacitance of 2013 mFcm−2 at a 5 mVs−1 scan rate, and 1886 mFcm−2 at a 25 mA applied current. Furthermore, the electrochemical behavior of MnFe-12h was examined by assembling an asymmetric cell device using activated carbon (AC) as a negative electrode and MnFe-12h as a positive electrode and it was tested in a wide voltage window range of 0.0 to 1.6 V. This asymmetric cell device achieved an appropriate energy density of 44.9 µW h cm−2 (55.01 W h kg−1), with a power density of 16 mW cm−2 (5000 W kg−1) at an applied current of 10 mA, and had a long-term cycling stability (93% capacitance retention after 5000 cycles) within the 1.6 V operating voltage window.
Effects of Composition Heterogeneities on Flame Kernel Propagation: A DNS Study
Authors: Er-raiy Aimad , Boukharfane Radouan , Parsani Matteo
Published: September 2020

In this study, a new set of direct numerical simulations is generated and used to examine the influence of mixture composition heterogeneities on the propagation of a premixed iso-octane/air spherical turbulent flame, with a representative chemical description. The dynamic effects of both turbulence and combustion heterogeneities are considered, and their competition is assessed. The results of the turbulent homogeneous case are compared with those of heterogeneous cases which are characterized by multiple stratification length scales and segregation rates in the regime of a wrinkled flame. The comparison reveals that stratification does not alter turbulent flame behaviors such as the preferential alignment of the convex flame front with the direction of the compression. However, we find that the overall flame front propagation is slower in the presence of heterogeneities because of the differential on speed propagation. Furthermore, analysis of different displacement speed components is performed by taking multi-species formalism into account. This analysis shows that the global flame propagation front slows down due to the heterogeneities caused by the reaction mechanism and the differential diffusion accompanied by flame surface density variations. Quantification of the effects of each of these mechanisms shows that their intensity increases with the increase in stratification’s length scale and segregation rate.
Mass Transport and Turbulent Statistics within Two Branching Coral Colonies
Authors: Hossain Md Monir , Staples Anne E.
Published: September 2020

Large eddy simulations were performed to characterize the flow and mass transport mechanisms in the interior of two Pocillopora coral colonies with different geometries, one with a relatively loosely branched morphology (P. eydouxi), and the other with a relatively densely branched structure (P. meandrina). Detailed velocity vector and streamline fields were obtained inside both corals for the same unidirectional oncoming flow, and significant differences were found between their flow profiles and mass transport mechanisms. For the densely branched P. meandrina colony, a significant number of vortices were shed from individual branches, which passively stirred the water column and enhanced the mass transport rate inside the colony. In contrast, vortices were mostly absent within the more loosely branched P. eydouxi colony. To further understand the impact of the branch density on internal mass transport processes, the non-dimensional Stanton number for mass transfer, St, was calculated based on the local flow time scale and compared between the colonies. The results showed up to a 219% increase in St when the mean vortex diameter was used to calculate St, compared to calculations based on the mean branch diameter. Turbulent flow statistics, including the fluctuating velocity components, the mean Reynolds stress, and the variance of the velocity components were calculated and compared along the height of the flow domain. The comparison of turbulent flow statistics showed similar Reynolds stress profiles for both corals, but higher velocity variations, in the interior of the densely branched coral, P. meandrina.
Authentication of Ginkgo biloba Herbal Products by a Novel Quantitative Real-Time PCR Approach
Authors: Grazina Liliana , Amaral Joana S. , Costa Joana , Mafra Isabel
Published: September 2020

Ginkgo biloba is a widely used medicinal plant. Due to its potential therapeutic effects, it is an ingredient in several herbal products, such as plant infusions and plant food supplements (PFS). Currently, ginkgo is one of the most popular botanicals used in PFS. Due to their popularity and high cost, ginkgo-containing products are prone to be fraudulently substituted by other plant species. Therefore, this work aimed at developing a method for G. biloba detection and quantification. A new internal transcribe spacer (ITS) marker was identified, allowing the development of a ginkgo-specific real-time polymerase chain reaction (PCR) assay targeting the ITS region, with high specificity and sensitivity, down to 0.02 pg of DNA. Additionally, a normalized real-time PCR approach using the delta cycle quantification (ΔCq) method was proposed for the effective quantification of ginkgo in plant mixtures. The method exhibited high performance parameters, namely PCR efficiency, coefficient of correlation and covered dynamic range (50–0.01%), achieving limits of detection and quantification of 0.01% (w/w) of ginkgo in tea plant (Camellia sinensis). The quantitative approach was successfully validated with blind mixtures and further applied to commercial ginkgo-containing herbal infusions. The estimated ginkgo contents of plant mixture samples suggest adulterations due to reduction or almost elimination of ginkgo. In this work, useful and robust tools were proposed to detect/quantify ginkgo in herbal products, which suggests the need for a more effective and stricter control of such products.
Application of a Novel Instantized Glycerol Monooleate Ingredient in a Protein-Stabilized Oil-In-Water Emulsion
Authors: Loi Chia Chun , Eyres Graham T. , Silcock Patrick , Birch E. John
Published: September 2020

Glycerol monooleate (GMO), casein and whey proteins are surfactants that can stabilize emulsion systems. This study investigates the impact of instantized GMO powders on creaming stability and oxidative stability in protein-stabilized emulsions. Model emulsions with bulk GMO, two instantized GMO powders, and two controls (without GMO) were produced by microfluidization. The droplet size, ζ-potential, viscosity, and creaming index of the emulsions were measured, while oxidative stability was evaluated by analysis of volatile compounds during storage (28 days, 45 °C) using gas chromatography mass spectrometry. Emulsions with GMO produced smaller average droplet sizes (180.0 nm) with a narrower distribution (polydispersity index of 0.161) compared to the controls (197.6 nm, 0.194). The emulsion stability of instantized emulsions was as good as bulk GMO, which were both better than controls. Based on the relative abundance of 3-octen-2-one, 2,4-heptadienal isomer 2, and 3,5-octadien-2-one isomer 1, the oxidative stability of the instantized emulsions was not significantly different from controls; however, bulk GMO emulsion showed significantly lower stability than controls. Instantized GMO powders can successfully produce physically stable protein-stabilized emulsions with good oxidative stability in a convenient powdered format.
Validation of an Analytical Method for Nitrite and Nitrate Determination in Meat Foods for Infants by Ion Chromatography with Conductivity Detection
Authors: Coviello Donatella , Pascale Raffaella , Ciriello Rosanna , Salvi Anna Maria , Guerrieri Antonio , Contursi Michela , Scrano Laura , Bufo Sabino A. , Cataldi Tommaso R.I. , Bianco Giuliana
Published: September 2020

Nitrate and nitrite as sodium or potassium salts are usually added to meat products to develop the characteristic flavor, to inhibit the growth of microorganisms (particularly Clostridium botulinum), and effectively control rancidity by inhibiting lipid oxidation. However, both nitrate and nitrite ions need to be monitored for ensuring the quality and safety of cured meats. In this work, for the first time the content of nitrite and nitrate ions in homogenized meat samples of baby foods was determined by a validated method based on ion chromatography (IC) coupled with conductivity detection. Recoveries of nitrate and nitrite ions in meat samples were not lower than 84 ± 6%. The detection limits of nitrate and nitrite were 0.08 mg L−1 and 0.13 mg L−1, respectively. Five commercial samples of homogenized meat, namely lamb, rabbit, chicken, veal, and beef, for infant feeding were investigated; while nitrite content was below the detection limit, nitrate ranged from 10.7 to 21.0 mg kg−1. The results indicated that nitrate contents were below the European (EU) fixed value of 200 mg kg−1, and an acceptable daily intake of 3.7 mg kg−1 was estimated.
Habitable Zones in Binary Star Systems: A Zoology
Authors: Eggl Siegfried , Georgakarakos Nikolaos , Pilat-Lohinger Elke
Published: September 2020

Several concepts have been brought forward to determine where terrestrial planets are likely to remain habitable in multi-stellar environments. Isophote-based habitable zones, for instance, rely on insolation geometry to predict habitability, whereas radiative habitable zones take the orbital motion of a potentially habitable planet into account. Dynamically informed habitable zones include gravitational perturbations on planetary orbits, and full scale, self consistent simulations promise detailed insights into the evolution of select terrestrial worlds. All of the above approaches agree that stellar multiplicity does not preclude habitability. Predictions on where to look for habitable worlds in such environments can differ between concepts. The aim of this article is to provide an overview of current approaches and present simple analytic estimates for the various types of habitable zones in binary star systems.
Connexin Hemichannel Mimetic Peptide Attenuates Cortical Interneuron Loss and Perineuronal Net Disruption Following Cerebral Ischemia in Near-Term Fetal Sheep
Authors: Yang Panzao , Davidson Joanne O. , Fowke Tania M. , Galinsky Robert , Wassink Guido , Karunasinghe Rashika N. , Prasad Jaya D. , Ranasinghe Sumudu , Green Colin R. , Bennet Laura , Gunn Alistair J. , Dean Justin M.
Published: September 2020

Perinatal hypoxia-ischemia is associated with disruption of cortical gamma-aminobutyric acid (GABA)ergic interneurons and their surrounding perineuronal nets, which may contribute to persisting neurological deficits. Blockade of connexin43 hemichannels using a mimetic peptide can alleviate seizures and injury after hypoxia-ischemia. In this study, we tested the hypothesis that connexin43 hemichannel blockade improves the integrity of cortical interneurons and perineuronal nets. Term-equivalent fetal sheep received 30 min of bilateral carotid artery occlusion, recovery for 90 min, followed by a 25-h intracerebroventricular infusion of vehicle or a mimetic peptide that blocks connexin hemichannels or by a sham ischemia + vehicle infusion. Brain tissues were stained for interneuronal markers or perineuronal nets. Cerebral ischemia was associated with loss of cortical interneurons and perineuronal nets. The mimetic peptide infusion reduced loss of glutamic acid decarboxylase-, calretinin-, and parvalbumin-expressing interneurons and perineuronal nets. The interneuron and perineuronal net densities were negatively correlated with total seizure burden after ischemia. These data suggest that the opening of connexin43 hemichannels after perinatal hypoxia-ischemia causes loss of cortical interneurons and perineuronal nets and that this exacerbates seizures. Connexin43 hemichannel blockade may be an effective strategy to attenuate seizures and may improve long-term neurological outcomes after perinatal hypoxia-ischemia.
Are the Current Account Imbalances on a Sustainable Path?
Authors: Narayan Seema , Sriananthakumar Sivagowry
Published: September 2020

This paper examines the current accounts of 16 developed and developing countries over the period 1970 to 2018. We test whether these nations satisfy their intertemporal solvency condition for external imbalances. The solvency condition in the strong form entails: (1) a cointegration, or a long run equilibrium, relationship between exports and imports of goods and services; and (2) an increase in imports leading to a proportional increase in exports. Our findings imply that the external imbalances are a cause of vulnerability for several nations. Bangladesh satisfies the abovementioned solvency condition—in other words, its current account is sustainable in the strong form. Australia, Ecuador, Honduras, Mexico, New Zealand, and Venezuela show weak forms of sustainability. For these six nations, the presence of a cointegration relationship between exports and imports coincides with less than proportional increases in exports with increases in imports. The current accounts of Chile and Paraguay are unsustainable—while their exports and imports are cointegrated, a growth in imports leads to a more than proportional increase in exports. For a few nations that failed the full sample (1970–2018) cointegration test, we developed sub-samples by anchoring the start date at 1970 and increasing the sample by every five years from 1999 to 2014. From the sub-samples, we find evidence of intermittent, but weak, cases of sustainability for Peru and South Africa. We show that Panama’s current account became unsustainable after 2009. China’s current account satisfied the strong form of sustainability between all sub-samples until 2014 and became unsustainable in the most recent four years (2015–2018). France, the Philippines, and the United States unequivocally failed the intertemporal solvency test in the full sample and sub-sample analyses. The cointegration tests allow for structural breaks in exports and imports. We find these breaks have strong economic significance. For instance, we find that for most countries the structural break in exports coincides with their worst economic recession.
The Effect of the Type and Amount of Synthetic Fibers on the Effectiveness of Dispersed Reinforcement in Soil-Cements
Authors: Brasse Krystian , Tracz Tomasz , Zdeb Tomasz
Published: September 2020

The paper deals with mechanical properties of soil-cement composites made with non-cohesive soil and reinforced with dispersed fibers. The research was carried out on the basis of three soil-cement matrices whose compositions varied in terms of the volumetric fraction of cement paste and the water-cement ratio. Two types of polypropylene fibers were used as dispersed reinforcement: single fibrillated-tapes polypropylene fibers (SFPF) and bundles of coiled fibrillated-tapes polypropylene fibers (BCFPF). The fibers varied in terms of their length and mass fraction. The objective of the study was to assess the effect of the addition of fibers to soil-cement composites on their flexural tensile strength and on their behavior in the post-critical state. The studies were carried out after 28 days of curing. Bending tests were carried out to determine post-critical stress values σCMODi, stress values at which the matrix is destroyed (limit of proportionality) σLOP, maximum stress values transferred by the fibers σMOR (modulus of rupture), and total fracture energy Gf,tot as well as compressive strength. The test results obtained, and their analysis, indicate the significant impact of the dispersed reinforcement used on the performance of such composites during bending.
Automation of the Leonardo da Vinci Machines
Authors: Bucolo Maide , Buscarino Arturo , Famoso Carlo , Fortuna Luigi , Gagliano Salvina
Published: September 2020

Leonardo da Vinci inventions and projects represent an intriguing starting point to remark the concept that innovation must be considered as a continuous route towards evolution in history. Some of the particular ideas and innovations presented by Leonardo da Vinci led us to formulate a link with automatic control. Selected models of the Leonardo da Vinci machines are presented in this paper, taking strictly into account the original mechanical schemes and working principles, but introducing modern low-cost control equipment, emphasizing the role of automatic control and that of electronic control devices, such as microcontrollers, sensors, and communication devices, to completely automate the Leonardo da Vinci machines. The approach outlined in the paper can be applied not only to other Leonardo machines but also to other mechanical equipment not necessarily designed by Leonardo da Vinci. Moreover, it is useful to remark that the approach followed in this paper can be very important also to introduce students, leading by example, to concepts typical of automation and for assisting in learning, keeping in mind the practical applications of advanced automation principles. The main research task of this paper is proving the efficacy of modern digital control techniques and teleoperation in strongly classical mechanical Leonardo machines, remarking that the projects of Leonardo are prompt to be efficiently controlled. This task could not be explored by Leonardo himself due to the lack of control technology. Moreover, the paper is addressed also to stimulate the young generations of engineers in joining classical mechanics with advanced technology. Therefore, the paper is also devoted to give focus on the fact that the Leonardo machines encompass all the key aspects of modern system engineering.
Filters in Strong BI-Algebras and Residuated Pseudo-SBI-Algebras
Authors: Zhang Xiaohong , Ma Xiangyu , Wang Xuejiao
Published: September 2020

The concept of basic implication algebra (BI-algebra) has been proposed to describe general non-classical implicative logics (such as associative or non-associative fuzzy logic, commutative or non-commutative fuzzy logic, quantum logic). However, this algebra structure does not have enough characteristics to describe residual implications in depth, so we propose a new concept of strong BI-algebra, which is exactly the algebraic abstraction of fuzzy implication with pseudo-exchange principle (PEP). Furthermore, in order to describe the characteristics of the algebraic structure corresponding to the non-commutative fuzzy logics, we extend strong BI-algebra to the non-commutative case, and propose the concept of pseudo-strong BI (SBI)-algebra, which is the common extension of quantum B-algebras, pseudo-BCK/BCI-algebras and other algebraic structures. We establish the filter theory and quotient structure of pseudo-SBI- algebras. Moreover, based on prequantales, semi-uninorms, t-norms and their residual implications, we introduce the concept of residual pseudo-SBI-algebra, which is a common extension of (non-commutative) residual lattices, non-associative residual lattices, and also a special kind of residual partially-ordered groupoids. Finally, we investigate the filters and quotient algebraic structures of residuated pseudo-SBI-algebras, and obtain a unity frame of filter theory for various algebraic systems.
Sensorless Speed Tracking of a Brushless DC Motor Using a Neural Network
Authors: Ramírez-Cárdenas Oscar-David , Trujillo-Romero Felipe
Published: September 2020

In this work, the sensorless speed control of a brushless direct current motor utilizing a neural network is presented. This control is done using a two-layer neural network that uses the backpropagation algorithm for training. The values provided by a Proportional, Integral, and Derivative (PID) control to this type of motor are used to train the network. From this PID control, the velocity values and their corresponding signal control (u) are recovered for different values of load pairs. Five different values of load pairs were used to consider the entire working range of the motor to be controlled. After carrying out the training, it was observed that the proposed network could hold constant load pairs, as well as variables. Several tests were carried out at the simulation level, which showed that control based on neural networks is robust. Finally, it is worth mentioning that this control strategy can be realized without the need for a speed sensor.
Bot Detection on Social Networks Using Persistent Homology
Authors: Nguyen Minh , Aktas Mehmet , Akbas Esra
Published: September 2020

The growth of social media in recent years has contributed to an ever-increasing network of user data in every aspect of life. This volume of generated data is becoming a vital asset for the growth of companies and organizations as a powerful tool to gain insights and make crucial decisions. However, data is not always reliable, since primarily, it can be manipulated and disseminated from unreliable sources. In the field of social network analysis, this problem can be tackled by implementing machine learning models that can learn to classify between humans and bots, which are mostly harmful computer programs exploited to shape public opinions and circulate false information on social media. In this paper, we propose a novel topological feature extraction method for bot detection on social networks. We first create weighted ego networks of each user. We then encode the higher-order topological features of ego networks using persistent homology. Finally, we use these extracted features to train a machine learning model and use that model to classify users as bot vs. human. Our experimental results suggest that using the higher-order topological features coming from persistent homology is promising in bot detection and more effective than using classical graph-theoretic structural features.
Molecular Characterization of the Myoliquefactive Fish Parasite Kudoa mirabilis (Cnidaria, Kudoidae) from SW Indian Ocean and Its Phylogenetic Relationship with the Kudoa thyrsites Species Complex
Authors: Giulietti Lucilla , Karlsbakk Egil , Cipriani Paolo , Shayo Salome Daniel , Storesund Julia E. , Levsen Arne
Published: September 2020

Myxosporean parasites of the genus Kudoa are fish parasites of great economic importance, as some species can affect the fish fillet quality by producing macroscopic cysts or generating post mortem myoliquefaction, commonly referred to as ‘soft flesh’. Kudoa mirabilis is a ‘soft flesh’-inducing species originally described based on morphology in the musculature of Trichiurus lepturus from the Indian Ocean. An integrative morphological and genetic characterization of K. mirabilis from the type host caught off the coast of Tanzania is here provided. The spores were stellate with four unequal polar capsules, showing similarities to Kudoa thyrsites. For comparative and validation purpose, K. mirabilis was compared morphologically and genetically with K. thyrsites reference isolates, including new obtained samples from the type host Thyrsites atun caught in the SE Atlantic Ocean. Morphological analyses of spores revealed key diagnostic characters clearly distinguishing the two Kudoa species. Phylogenetic analyses based on SSU and LSU rRNA genes demonstrated that K. mirabilis is a distinct and valid species, representing a sister group to a K. thyrsites subclade that comprises several isolates from Japan and one single isolate from South Africa. This finding raises questions about the true diversity likely hidden in the K. thyrsites complex.
Bubble Properties in Bubbling and Turbulent Fluidized Beds for Particles of Geldart’s Group B
Authors: Wytrwat Tom , Yazdanpanah Mahdi , Heinrich Stefan
Published: September 2020

Predicting bubble properties in fluidized beds is of high interest for reactor design and modeling. While bubble sizes and velocities for low velocity bubbling fluidized beds have been examined in several studies, there have been only few studies about bubble behavior at superficial gas velocities up into the turbulent regime. For this reason, we performed a thorough investigation of the size, shape and velocity of bubbles at superficial gas velocities ranging from 0.18 m/s up to 1.6 m/s. Capacitance probes were used for the determination of the bubble properties in three different fluidized bed facilities sized of 0.1 m, 0.4 m and 1 m in diameter. Particles belonging to Geldart’s group B (Sauter mean diameter: 188 µm, solid density: ρs = 2600 kg/m3) were used. Correlations for the determination of bubble phase holdup, vertical bubble length and bubble velocity are introduced in this work. The shape of bubbles was found to depend on superficial gas velocity. This implies that at large superficial gas velocities the horizontal size of a bubble must be much smaller in comparison to its vertical size. This leads to a decrease of pressure fluctuations, which is observed in the literature as a characteristic of transitioning into a turbulent regime.
MILP Formulation for Solving and Initializing MINLP Problems Applied to Retrofit and Synthesis of Hydrogen Networks
Authors: Silva Patrícia R. da , Aragão Marcelo E. , Trierweiler Jorge O. , Trierweiler Luciane F.
Published: September 2020

The demand for hydrogen in refineries is growing due to its importance as a sulfur capture element. Therefore, hydrogen management is critical for fulfilling demands as efficiently as possible. Through mathematical modeling, hydrogen network management can be better performed. Cost-efficient Mixed-Integer Linear Programming (MILP) and Mixed-Integer Nonlinear Programming (MINLP) optimization models for (re)designing were proposed and implemented in GAMS with two case studies. Linear programming has the limitation of no stream mixing allowed; therefore, to overcome this limitation, an algorithm-based procedure called the Virtual Compressor Approach was proposed. Based on the MILP optimal solution obtained, the streams and compressors were merged. As a result, the number of compressors was reduced, along with the inherent investment costs. An operational cost reduction of more than 28% (example 1) and 26% (example 2) was obtained with a linear model. The optimal MILP solution after rearranging compressors was then provided as a good starting point to the MINLP. The operating costs were decreased by more than 31% (example 1) and 32% (example 2). Most of the cost reduction was obtained only with the usage of the MILP model. Besides, a higher level of cost reduction was only obtained when the linear model was used as the starting point.
Numerical Study on the Influence of Step Casing on Cavitating Flows and Instabilities in Inducers with Equal and Varying Pitches
Authors: Yu Lu , Zhang Haochen , Chen Hui , Zuo Zhigang , Liu Shuhong
Published: September 2020

It is known that cavitating flow characteristics and instabilities in inducers can greatly impact the safety and stability of a liquid rocket. In this paper, step casing optimization design (Model OE and Model AE) was carried out for two three-bladed inducers with an equal (Model O) and a varying pitch (Model A), respectively. The unsteady cavitation flow field and accompanied instabilities were studied via numerical simulations. Reductions of the cavity size and fluctuation were observed in cases with a step casing. A significant difference in cavity structures was seen as well. Referring to the pressure distributions on the blades and details of the flow field, the mechanism of cavitation suppression was revealed. This work provides a feasible and convenient method in engineering practice for optimizing the characteristic of the cavitating flow field and instabilities for the inducer.
Comparative Analysis of Object Digitization Techniques Applied to the Characterization of Deformed Materials in Ballistic Tests
Authors: Dmengeon Pedreiro Balbino Filipe , Aracélly Reis Medeiros Khrissy , Roberto Hall Barbosa Carlos
Published: September 2020

Several three-dimensional scanning methods have been developed and improved over the past 40 years. The peculiarities of each technique, associated with the computational advances of the period, allowed the increasing application and diffusion of the technology in several sectors, among them those related to metrology in ballistics and the testing of protective materials. The specific goal of such ballistic tests is to estimate the depth of indentation caused by projectiles. In particular, this study presents a comparative analysis between two three-dimensional optical scanning methods, taking into account the same object of interest. The comparative analysis was based on reference planes detected by Random Sample Consensus methodology in each cloud. By comparing the results of the different techniques, it was found for this case that three-dimensional reconstruction by stereo images estimated values closer to the real ones in comparison to those estimated by the structured light scanner, mainly due to the fact that, for three-dimensional reconstruction, the image acquisition was conducted statically.
CSNOMA: Carrier Sense Non-Orthogonal Multiple Access
Authors: Kim Dong Min , Kim Seong-Lyun
Published: September 2020

In this paper, we investigate the possibility of the cross-layer design of a distributed random access scheme with considering physical (PHY) and multiple access control (MAC) layers, which utilizes the interference cancellation technique. In this regard, we propose a new multiple access protocol, named carrier sense non-orthogonal multiple access (CSNOMA). We consider the spatially randomly distributed interferers to realistically capture the effect of interference. The proposed protocol shows better area spectral efficiency than carrier sense multiple access (CSMA), as the node density increases. We also present a practical signaling design compatible with IEEE 802.11 DCF mode.
Modeling Car-Following Behaviors and Driving Styles with Generative Adversarial Imitation Learning
Authors: Zhou Yang , Fu Rui , Wang Chang , Zhang Ruibin
Published: September 2020

Building a human-like car-following model that can accurately simulate drivers’ car-following behaviors is helpful to the development of driving assistance systems and autonomous driving. Recent studies have shown the advantages of applying reinforcement learning methods in car-following modeling. However, a problem has remained where it is difficult to manually determine the reward function. This paper proposes a novel car-following model based on generative adversarial imitation learning. The proposed model can learn the strategy from drivers’ demonstrations without specifying the reward. Gated recurrent units was incorporated in the actor-critic network to enable the model to use historical information. Drivers’ car-following data collected by a test vehicle equipped with a millimeter-wave radar and controller area network acquisition card was used. The participants were divided into two driving styles by K-means with time-headway and time-headway when braking used as input features. Adopting five-fold cross-validation for model evaluation, the results show that the proposed model can reproduce drivers’ car-following trajectories and driving styles more accurately than the intelligent driver model and the recurrent neural network-based model, with the lowest average spacing error (19.40%) and speed validation error (5.57%), as well as the lowest Kullback-Leibler divergences of the two indicators used for driving style clustering.
Origin of the 16S Ribosomal Molecule from Ancestor tRNAs
Authors: de Farias Savio Torres , Rêgo Thais Gaudêncio , José Marco V.
Published: September 2020

We tested the hypothesis that concatemers of ancestral tRNAs gave rise to the 16S ribosomal RNA. We built an ancestral sequence of proto-tRNAs that showed a significant identity of 51.69% and a percentage of structural identity of 0.941 with the 16S ribosomal molecule. We also propose a hypothesis for the emergence of translation.
Preparedness and Multiagency Collaboration—Lessons Learned from a Case Study in the Norwegian Armed Forces
Authors: Steiro Trygve J. , Torgersen Glenn-Egil
Published: September 2020

The objective of this study is to investigate the structure for learning and the learning outcomes from a paper exercise based on multiagency collaboration, and point to potential benefits for crisis leadership and management in civil organizations. The current study was conducted by participant observation in one exercise and a questionnaire was handed out in the following exercise to measure outcomes. Social interaction and concurrent learning are used as the theoretical foundation in the current study. The exercise can be used as an input for multiagency collaboration when linked to the strategic and operative context. The Norwegian Armed Forces operate from a leadership perspective of intention-based leadership. The organization has also developed a pedagogical platform that guides learning activities. In a complex world, we aim at finding training areas that can prepare the cadets for scenarios that also heavily involve the unforeseen. Improvisation is seen as important for military leaders and the exercise provides a sound arena for this purpose. We have seen that even for a table exercise, important lessons can be learned. The current study makes suggestions as well as improvements that could be performed based on the lessons learned for both the Norwegian Armed Forces as well as for other organizations that find the experiences interesting. The article identified five management principles for interaction under unforeseen conditions: (1) develop a pedagogical view for the organization, (2) facilitate and train using processes for complementary process development, (3) develop precise and common language, (4) train the organization in concurrent learning, (5) develop tolerance and mutual respect.
Assessment of Lifestyle and Eating Habits among a Nationally Representative Sample of Iranian Adolescent Girls: the CASPIAN-V Study
Authors: Shayan-Moghadam Ramin , Heidari-Beni Motahar , Riahi Roya , Motlagh Mohammad Esmail , Fesharaki Shahin , Heshmat Ramin , Daniali Seyedeh Shahrebanoo , Kelishadi Roya
Published: September 2020

Background: The present study assess lifestyle and eating habits of Iranian adolescent girls. Methods: This cross-sectional study was conducted on 3207 adolescent girls, aged 12–18 years. Lifestyle and eating habits of adolescents were assessed. Results: The prevalence of overweight was 11.3% and that of obesity was 10.2%. The frequencies of daily intake of fruits, dairy products and vegetables were 60.9%, 45.6 % and 33.5%, respectively. Skipping breakfast (15.8%) was more frequent than skipping dinner or lunch. Moreover, 10.6% of subjects had fast food daily and 16.2% had fast food weekly. Overall, 55.2% of participants watched television for at least 2 hours a day; and 27.1% reported to have a sleeping time of less than 8 hours a day. Low physical activity, i.e. less than 30 minutes per day, was less frequent among participants with high socio-economic status (SES) compared to those with medium or low SES (57.6% vs. 61.3% and 64.1%, respectively, P value = 0.010). Conclusion: Improvement of lifestyle habits should be considered in public health plans for health promotion of adolescent girls and the next generation. Primordial prevention of chronic diseases by improving healthy lifestyle of adolescent girls should be a national public health priority
Detection and Parameter Extraction of Low Probability of Intercept Radar Signals using the Hough Transform
Authors: Stevens Daniel L. , Schuckers Stephanie A.
Published: September 2020

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques, such as the Wigner-Ville distribution, Choi-Williams distribution, spectrogram, and scalogram, for the purpose of analyzing low probability of intercept radar signals (e.g. triangular modulated frequency modulated continuous wave and frequency shift keying). Although these classical time-frequency techniques are an improvement over the Fourier-based analysis, they still suffer from a lack of readability, due to cross-term interference, and a mediocre performance in low SNR environments. This lack of readability may lead to inaccurate detection and parameter extraction of these radar signals. In this paper, the use of the Hough transform, because of its ability to suppresscross-term interference, separate signals from cross-terms, and perform well in the presence of noise, is proposed as an improved signal analysis technique. With these qualities, the Hough transform has the potential to produce better readability and consequently, more accurate signal detection and parameter extraction metrics.
Replication is Important for Educational Psychology: Recent Developments and Key Issues
Authors: Plucker Jonathan , Makel Matthew C.
Published: September 2020

Replication is a key activity in scientific endeavors. Yet explicit replications are rare in many fields, including education and psychology. In this paper, we discuss the relevance and value of replication in educational psychology and analyze challenges regarding the role replications can and should play in research. These challenges include philosophical, methodological, professional, and utility concerns about replication in education and the social sciences more broadly. Finally, we discuss strategies that may address these concerns in educational psychology research.