bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Reach DWDM-Passive Optical Fiber Sensor Network for Water Level Monitoring of Spent Fuel Pool in Nuclear Power Plant
Authors: Lee Hoon-Keun , Choo Jaeyul , Shin Gangsig , Kim Joonyoung
Published: July 2020

This paper presents a passive optical fiber sensor network based on the dense wavelength division multiplexing (DWDM) to remotely monitor the water level of the spent fuel pool in nuclear power plants. In states of emergency, such as a tsunami, safety information must be secured for rapid response, in spite of all power losses in the plant. We consider the proposed passive sensor network to be one of the best solutions that is able to provide the remote (more than tens of kilometers) monitoring station with the highly reliable on-site information. The principle of water level measurement is based on the change of Fresnel reflection power coefficient at sensing units, which are installed according to the water levels in a row. The sensing units that play the role of reflector and modulator at the same time are connected to an arrayed waveguide grating (AWG) for DWDM. By measuring the spectrum of the optical signal transferred from the sensing units, the water level can be determined in real-time. However, in the remote sensing, the system performance can be seriously degraded due to the Rayleigh Back-Scattering (RBS) of the seeded amplified spontaneous emission (ASE) light that is induced at the fiber-optic link. As such, we investigate the effect of RBS on the remote (more than tens of kilometers) sensing performance of the proposed network. Following the theoretical analysis, we propose a simple network configuration to overcome the RBS issue by utilizing two different transmission paths: one for downstream of the ASE seed light, and the other for upstream of the optical signals coming from the sensing units. Based on the proposed configuration, the maximum sensing distance can be increased up to 42.5 km without the support of any optical amplifier.
All-Fiber Measurement of Surface Tension Using a Two-Hole Fiber
Authors: Guzman-Sepulveda Jose R. , May-Arrioja Daniel A. , Fuentes-Fuentes Miguel A. , Cuando-Espitia Natanael , Torres-Cisneros Miguel , Gonzalez-Gutierrez Karina , LiKamWa Patrick
Published: July 2020

An all-fiber approach is presented to measure surface tension. The experimental realization relies on the use of a specialty fiber, a so-called two-hole fiber (THF), which serves a two-fold purpose: providing a capillary channel to produce bubbles while having the means to measure the power reflected at the end facet of the fiber core. We demonstrate that provided a controlled injection of gas into the hollow channels of the THF, surface tension measurements are possible by simply tracking the Fresnel reflection at the distal end of the THF. Our results show that the characteristic times involved in the bubble formation process, from where the surface tension of the liquids under test is retrieved, can be measured from the train of pulses generated by the continuous formation and detachment of bubbles.
Implementation of Analog Perceptron as an Essential Element of Configurable Neural Networks
Authors: Geng Chao , Sun Qingji , Nakatake Shigetoshi
Published: July 2020

Perceptron is an essential element in neural network (NN)-based machine learning, however, the effectiveness of various implementations by circuits is rarely demonstrated from chip testing. This paper presents the measured silicon results for the analog perceptron circuits fabricated in a 0.6 μm/±2.5 V complementary metal oxide semiconductor (CMOS) process, which are comprised of digital-to-analog converter (DAC)-based multipliers and phase shifters. The results from the measurement convinces us that our implementation attains the correct function and good performance. Furthermore, we propose the multi-layer perceptron (MLP) by utilizing analog perceptron where the structure and neurons as well as weights can be flexibly configured. The example given is to design a 2-3-4 MLP circuit with rectified linear unit (ReLU) activation, which consists of 2 input neurons, 3 hidden neurons, and 4 output neurons. Its experimental case shows that the simulated performance achieves a power dissipation of 200 mW, a range of working frequency from 0 to 1 MHz, and an error ratio within 12.7%. Finally, to demonstrate the feasibility and effectiveness of our analog perceptron for configuring a MLP, seven more analog-based MLPs designed with the same approach are used to analyze the simulation results with respect to various specifications, in which two cases are used to compare to their digital counterparts with the same structures.
Simultaneous Measurement of Temperature and Mechanical Strain Using a Fiber Bragg Grating Sensor
Authors: Her Shiuh-Chuan , Lin Wei-Nan
Published: July 2020

Based on the shift of the Bragg wavelength, fiber Bragg grating (FBG) sensors have been employed to measure a variety of physical parameters such as stress, strain, displacement, temperature, vibration and pressure. In this work, a simple and easy way to be implemented FBG sensing methodology was proposed to measure the temperature and strain simultaneously. Half of the FBG was bonded on the host structure, while the other half of the FBG was left free. The host structure was an aluminum test specimen with dimensions of 20 × 3.8 × 0.5 cm3. As the host structure subjected to mechanical and thermal loadings, the Bragg wavelengths reflected from the bonded and unbonded FBGs are different. Theoretical predictions of the Bragg wavelength shifts of the bonded and unbonded FBGs were presented. Utilizing the Bragg wavelength shift of unbonded FBG, the temperature can be determined and is independent of mechanical strain. The Bragg wavelength shift of the bonded FBG allows the determination of the mechanical strain. The temperature measured by FBG sensor was compared with the result from a thermocouple, while the mechanical strain was validated with the theoretical prediction. Good agreement between the experimental measurement and theoretical prediction demonstrates that temperature-strain discrimination can be realized using the proposed method with one single FBG sensor.
A Scale-Adaptive Matching Algorithm for Underwater Acoustic and Optical Images
Authors: Liu Jun , Li Benyuan , Guan Wenxue , Gong Shenghua , Liu Jiaxin , Cui Junhong
Published: July 2020

Underwater acoustic and optical data fusion has been developed in recent decades. Matching of underwater acoustic and optical images is a fundamental and critical problem in underwater exploration because it usually acts as the key step in many applications, such as target detection, ocean observation, and joint positioning. In this study, a method of matching the same underwater object in acoustic and optical images was designed, consisting of two steps. First, an enhancement step is used to enhance the images and ensure the accuracy of the matching results based on iterative processing and estimate similarity. The acoustic and optical images are first pre-processed with the aim of eliminating the influence of contrast degradation, contour blur, and image noise. A method for image enhancement was designed based on iterative processing. In addition, a new similarity estimation method for acoustic and optical images is also proposed to provide the enhancement effect. Second, a matching step is used to accurately find the corresponding object in the acoustic images that appears in the underwater optical images. In the matching process, a correlation filter is applied to determine the correlation for matching between images. Due to the differences of angle and imaging principle between underwater optical and acoustic images, there may be major differences of size between two images of the same object. In order to eliminate the effect of these differences, we introduce the Gaussian scale-space, which is fused with multi-scale detection to determine the matching results. Therefore, the algorithm is insensitive to scale differences. Extensive experiments demonstrate the effectiveness and accuracy of our proposed method in matching acoustic and optical images.
Hardware for Recognition of Human Activities: A Review of Smart Home and AAL Related Technologies
Authors: Sanchez-Comas Andres , Synnes Kåre , Hallberg Josef
Published: July 2020

Activity recognition (AR) from an applied perspective of ambient assisted living (AAL) and smart homes (SH) has become a subject of great interest. Promising a better quality of life, AR applied in contexts such as health, security, and energy consumption can lead to solutions capable of reaching even the people most in need. This study was strongly motivated because levels of development, deployment, and technology of AR solutions transferred to society and industry are based on software development, but also depend on the hardware devices used. The current paper identifies contributions to hardware uses for activity recognition through a scientific literature review in the Web of Science (WoS) database. This work found four dominant groups of technologies used for AR in SH and AAL—smartphones, wearables, video, and electronic components—and two emerging technologies: Wi-Fi and assistive robots. Many of these technologies overlap across many research works. Through bibliometric networks analysis, the present review identified some gaps and new potential combinations of technologies for advances in this emerging worldwide field and their uses. The review also relates the use of these six technologies in health conditions, health care, emotion recognition, occupancy, mobility, posture recognition, localization, fall detection, and generic activity recognition applications. The above can serve as a road map that allows readers to execute approachable projects and deploy applications in different socioeconomic contexts, and the possibility to establish networks with the community involved in this topic. This analysis shows that the research field in activity recognition accepts that specific goals cannot be achieved using one single hardware technology, but can be using joint solutions, this paper shows how such technology works in this regard.
A Systematic Review of IoT Solutions for Smart Farming
Authors: Navarro Emerson , Costa Nuno , Pereira António
Published: July 2020

The world population growth is increasing the demand for food production. Furthermore, the reduction of the workforce in rural areas and the increase in production costs are challenges for food production nowadays. Smart farming is a farm management concept that may use Internet of Things (IoT) to overcome the current challenges of food production. This work uses the preferred reporting items for systematic reviews (PRISMA) methodology to systematically review the existing literature on smart farming with IoT. The review aims to identify the main devices, platforms, network protocols, processing data technologies and the applicability of smart farming with IoT to agriculture. The review shows an evolution in the way data is processed in recent years. Traditional approaches mostly used data in a reactive manner. In more recent approaches, however, new technological developments allowed the use of data to prevent crop problems and to improve the accuracy of crop diagnosis.
Gain-Phase Errors Calibration for a Linear Array Based on Blind Signal Separation
Authors: Dai Zheng , Su Weimin , Gu Hong
Published: July 2020

In this paper, a non-iterative blind calibration algorithm for gain-phase errors is proposed. A mixing matrix is first obtained from the received observation data through blind signal separation. The mixing matrix is the product of the gain-phase error matrix and the ideal array manifold matrix. Then, a spatial spectrum is constructed by using the estimated mixed matrix. The direction corresponding to the maximum point of the spectral function is proved to be the azimuth of a certain source. Therefore, after the direction-of-arrival (DOA) is obtained by a one-dimensional spectrum search, the active calibration method can be used to estimate the gain-phase errors. The proposed algorithm is not limited to the calibration for uniform linear array (ULA), but also applicable to a non-uniform linear array. Moreover, the estimation performance of the algorithm will not be affected by the magnitude of the gain errors. Some simulations are given to verify the effectiveness and performance of the algorithm.
Geometric Nonlinear Model for Prediction of Frequency–Temperature Behavior of SAW Devices for Nanosensor Applications
Authors: Chen Zhenglin , Zhang Qiaozhen , Li Congcong , Fu Sulei , Qiu Xiaojun , Wang Xiaoyu , Wu Haodong
Published: July 2020

Surface acoustic wave (SAW)-based sensors have become highly valued for their use as nanosensors in industrial applications. Accurate prediction of the thermal stability is a key problem for sensor design. In this work, a numerical tool based on the finite element method combined with piezoelectric Lagrangian equations has been developed to accurately predict the thermal sensitivity characteristics of surface acoustic wave devices. Theoretical analysis for the geometric nonlinearity contributing to the frequency–temperature characteristic and material constants’ dependency on temperature were taken into consideration. The thermomechanical equilibrium equation built on the three-dimensional finite element method (3D-FEM) mesh node took mesh movement into account because thermal expansion was employed. The frequency–temperature characteristics of different SAW modes, including Rayleigh waves and leaky waves excited on a piezoelectric substrate of quartz or lithium tantalate, respectively, were calculated. The theoretical accuracy of the proposed numerical tool was verified by experiments.
A Pilot Study to Assess the Reliability of Sensing Joint Acoustic Emissions of the Wrist
Authors: Hochman Daniel M. , Gharehbaghi Sevda , Whittingslow Daniel C. , Inan Omer T.
Published: July 2020

Joint acoustic emission (JAE) sensing has recently proven to be a viable technique for non-invasive quantification indicating knee joint health. In this work, we adapt the acoustic emission sensing method to measure the JAEs of the wrist—another joint commonly affected by injury and degenerative disease. JAEs of seven healthy volunteers were recorded during wrist flexion-extension and rotation with sensitive uniaxial accelerometers placed at eight locations around the wrist. The acoustic data were bandpass filtered (150 Hz–20 kHz). The signal-to-noise ratio (SNR) was used to quantify the strength of the JAE signals in each recording. Then, nine audio features were extracted, and the intraclass correlation coefficient (ICC) (model 3,k), coefficients of variability (CVs), and Jensen–Shannon (JS) divergence were calculated to evaluate the interrater repeatability of the signals. We found that SNR ranged from 4.1 to 9.8 dB, intrasession and intersession ICC values ranged from 0.629 to 0.886, CVs ranged from 0.099 to 0.241, and JS divergence ranged from 0.18 to 0.20, demonstrating high JAE repeatability and signal strength at three locations. The volunteer sample size is not large enough to represent JAE analysis of a larger population, but this work will lay a foundation for future work in using wrist JAEs to aid in diagnosis and treatment tracking of musculoskeletal pathologies and injury in wearable systems.
Encapsulation of Electrically Conductive Apparel Fabrics: Effects on Performance
Authors: Wilson Sophie , Laing Raechel , Tan Eng Wui , Wilson Cheryl
Published: July 2020

Electrically conductive fabrics are achieved by functionalizing with treatments such as graphene; however, these change conventional fabric properties and the treatments are typically not durable. Encapsulation may provide a solution for this, and the present work aims to address these challenges. Next-to-skin wool and cotton knit fabrics functionalized using graphene ink were encapsulated with three poly(dimethylsiloxane)-based products. Properties known to be critical in a next-to-skin application were investigated (fabric structure, moisture transfer, electrical conductivity, exposure to transient ambient conditions, wash, abrasion, and storage). Wool and cotton fabrics performed similarly. Electrical conductivity was conferred with the graphene treatment but decreased with encapsulation. Wetting and high humidity/low temperature resulted in an increase in electrical conductivity, while decreases in electrical conductivity were evident with wash, abrasion, and storage. Each encapsulant mitigated effects of exposures but these effects differed slightly. Moisture transfer changed with graphene and encapsulants. As key performance properties of the wool and cotton fabrics following treatment with graphene and an encapsulant differed from their initial state, use as a patch integrated as part of an upper body apparel item would be acceptable.
An Asset-Based Perspective of the Economic Contributions of Latinx Communities: An Illinois Case Study
Authors: García Ivis , Sönmez Zafer
Published: July 2020

The study aims to measure Latinx share of economic activities and highlight and its increasing role in the economic future of their state. As a methodology we use input-output model-based IMPLAN to calculate the economic footprint of Latinx in Illinois. We demonstrate how this labor force has allowed the state to expand production and purchasing power. In the conclusion we discuss how this line of investigation allows us to explore what decision makers can do to facilitate a Latinx action agenda from the asset-based perspective.
Pre-Service Teachers’ Critical Digital Literacy Skills and Attitudes to Address Social Problems
Authors: Castellví Jordi , Díez-Bedmar María-Consuelo , Santisteban Antoni
Published: July 2020

The emergence and expansion of social networks in the digital age has led to social transformations that have a great impact within the field of education. Teacher-training programs face the challenge of preparing future teachers to critically interpret digital media. They must succeed in this if we are to develop citizens who are well informed and reflective, which then raises the question: Are future teachers critical thinkers? This study took third- and fourth-year students of primary education (n = 322) at five Spanish universities and explored their capacity for constructing critical discourses. It examined how well they can analyze and discuss information from digital media on social problems like poverty, economic crises, social justice, and the media. Its findings reveal that future teachers have difficulty in putting together critical discourses based on information from the Internet on social problems. Those who have doubts, compare, analyze, and reason are the minority.
The Factors that Affect Usage Intentions and Travel Intentions of Travel-Related WeChat Official Accounts
Authors: Wang Yanyan , Lin Yann-Jou , Lin Bau-Show
Published: July 2020

WeChat Official Accounts (WOAs)—a feature of WeChat—are thriving. However, studies on travel-related WOAs remain scarce and lack depth. This study aimed to identify the factors that influence usage intentions and travel intentions in regard to travel-related WOAs. Based on the Uses and Gratifications (U&G) theory, this study developed a theoretical model and examined the model through a web-based questionnaire. The questionnaire was distributed through the online survey tool Sojump. After analyzing the obtained data via structural equation modeling, the results revealed that: (1) social, entertainment, and information motivations are the primary factors influencing usage intentions; (2) information and entertainment motivations are important factors influencing travel intentions; and (3) usage intentions positively affect travel intentions and play a mediating role. The findings carry theoretical and practical significance regarding how travel-related WOAs can improve users’ usage and travel intentions, as well as value for the actual management and marketing of WOAs.
Spatializing an Artist-Resident Community Area at a Building-Level: A Case Study of Garosu-Gil, South Korea
Authors: Park Jiman , Kim Jihang , Yang Byungyun
Published: July 2020

This study integrated a focus on geographical, physical, and commercial characteristics to explore the commercial gentrification phenomenon and its related statistical summaries in the area of Garosu-gil in Seoul’s Sinsa-dong ward. In particular, this study first collected parcel and building data and corresponding attribute information and mapped the resulting datasets in a geographic information system (GIS) environment. We then examined gentrification issues per building and conducted statistical analyses to investigate spatial patterns of commercial gentrification, which were used to develop criteria for determining degrees of gentrification. Third, this study conducted correlation and regression analyses to quantify the strength of the linear relationship between pairs of variables associated with primary factors contributing to commercial gentrification, and used a geographically weighted regression model (GWR) to help understand and predict spatial relationships between significant variables. The results showed positive correlations between several variables and commercial gentrification in the study area, namely neighborhood-convenience facilities, building ages, store rents, new franchise and restaurant businesses, distance to subways, and the presence of multiple roads. Based on its finding, there are key contributions of this study as follows. The first significant contribution of this study is developing measurement of gentrification levels that can be used by policy makers at each of four stages of the gentrification process. Furthermore, this paper develops a comprehensive approach for spatially identifying gentrifying neighborhoods across multiple time periods in 2- and 3-dimensions. It eventually helps urban planners implement preventative or supportive programs to protect lower-income residents and small businesses and thereby engender more sustainable community development.
External Costs of Agriculture Derived from Payments for Agri-Environment Measures: Framework and Application to Switzerland
Authors: Schläpfer Felix
Published: July 2020

The costs of unintended side effects of agriculture such as water pollution cannot be directly observed in markets. However, the values society places on healthy agricultural environments are increasingly reflected in payments to farmers for measures to avoid or reduce environmental damage. This paper presents a framework for estimating external costs of agriculture from payment rates of agri-environment measures addressing specific externality issues. The framework is applied to the broad range of agri-environment measures implemented in Swiss agricultural policy. Estimates of external costs are derived for emissions of greenhouse gases, ammonia, nitrate and pesticides, soil erosion, habitat deficits, and animal suffering. The total external costs of Swiss agriculture are estimated at CHF 3.651 billion (CHF 3494 per hectare) when the calculations are based on the agri-environment measures’ average avoidance costs and of CHF 5.560 billion (CHF 5321 per hectare) when the calculations are based on highest observed avoidance costs. Potential applications include internalization policies, evaluations of agri-environment support, and integrated environmental and economic accounting.
Leveraging Digital Approaches for Transparency in Sustainable Supply Chains: A Conceptual Paper
Authors: Ebinger Frank , Omondi Bramwel
Published: July 2020

With the growing global interdependence of companies, their scope of responsibility for the environmental, social, and human rights impacts associated with their activities is also growing. In this context, companies are increasingly held accountable for social and ecological issues that lie within the sphere of action of their suppliers and sub-suppliers. They are thus faced with the challenge of meeting these demands for transparency, traceability, and compliance with standards in their Supply Chains (SCs). Based on the theoretical framework of Sustainable Supply Chain Transparency (SSCT) in Sustainable Supply Chain Management (SSCM), this conceptual article aims at initiating the discussion on digitalization in SSCM. Therefore, a heuristical research framework, based on relevant fields in the management of sustainability oriented transparency (governance, cooperation and partner selection, traceability/tracking, and strategic and operational risk assessment) is developed. In relation to these fields, consequently, data-driven digital approaches are identified to which potentials for SSCT and control can be attributed. This initial analysis of existing digital approaches already shows that the market is developing dynamically, but is driven more by individual initiatives. In many cases, the approaches used so far are still in the trial phase or offer only limited solutions. Therefore, this paper contributes by giving an overview of the current application of the digitalization approaches in SSCM pinning our discussion on SSCT dimensions.
Using a Fuzzy Analytic Hierarchy Process to Formulate an Effectual Tea Assessment System
Authors: Fu Hwai-Hui , Chen Yan-Yu , Wang Guan-Jie
Published: July 2020

Taiwan tea is very famous around the world. This study aims to establish a quantized tea assessment system to increase the credibility of the current tea evaluation mechanism. In this study, a new procedure using a fuzzy analytic hierarchy process integrated with linguistic variables is proposed to set up measurable indicators and determine their weights for a tea evaluation mechanism. An affinity diagram was used to deduce three dimensions (i.e., tea farm management, the tea-making process, and organoleptic evaluation) and 11 evaluation criteria for the construction of the tea assessment system. Sixteen experts, including 10 senior tea farmers and six national tea appraisers, were invited to participate in the one-on-one linguistic questionnaire survey. Analysis of the fuzzy analytic hierarchy process shows that tea farm management gains the most weight (0.533), followed by the tea-making process (0.329), and organoleptic evaluation (0.138). Surprisingly, organoleptic evaluation, as the assessment criteria today, places last in the three evaluation dimensions. Findings of this study can provide the Taiwan Tea Association with insightful information for enhancing the current tea assessment system.
Topological Symmetry Transition between Toroidal and Klein Bottle Graphenic Systems
Authors: Putz Mihai V. , Ori Ottorino
Published: July 2020

In the current study, distance-based topological invariants, namely the Wiener number and the topological roundness index, were computed for graphenic tori and Klein bottles (named toroidal and Klein bottle fullerenes or polyhexes in the pre-graphene literature) described as closed graphs with N vertices and 3N/2 edges, with N depending on the variable length of the cylindrical edge LC of these nano-structures, which have a constant length LM of the Möbius zigzag edge. The presented results show that Klein bottle cubic graphs are topologically indistinguishable from toroidal lattices with the same size (N, LC, LM) over a certain threshold size LC. Both nano-structures share the same values of the topological indices that measure graph compactness and roundness, two key topological properties that largely influence lattice stability. Moreover, this newly conjectured topological similarity between the two kinds of graphs transfers the translation invariance typical of the graphenic tori to the Klein bottle polyhexes with size LC ≥ LC, making these graphs vertex transitive. This means that a traveler jumping on the nodes of these Klein bottle fullerenes is no longer able to distinguish among them by only measuring the chemical distances. This size-induced symmetry transition for Klein bottle cubic graphs represents a relevant topological effect influencing the electronic properties and the theoretical chemical stability of these two families of graphenic nano-systems. The present finding, nonetheless, provides an original argument, with potential future applications, that physical unification theory is possible, starting surprisingly from the nano-chemical topological graphenic space; thus, speculative hypotheses may be drawn, particularly relating to the computational topological unification (that is, complexification) of the quantum many-worlds picture (according to Everett’s theory) with the space-curvature sphericity/roundness of general relativity, as is also currently advocated by Wolfram’s language unification of matter-physical phenomenology.
The Problem of Invariance in Nonlinear Discrete-Time Dynamic Systems
Authors: Zhirabok Alexey
Published: July 2020

The paper considers the problem of invariance with respect to the unknown input for discrete-time nonlinear dynamic systems. To solve the problem, the algebraic approaches, called algebra of functions and logic–dynamic approach, are used. Such approaches assume that description of the system may contain non-differentiable functions. Necessary and sufficient conditions of solvability the problem are obtained. Moreover, procedures which find the appropriate functions and matrices are developed. Some applications of such invariance in fault detection and isolation, disturbance decoupling problem, and fault-tolerant control are considered.
Discretization Algorithm for Incomplete Economic Information in Rough Set Based on Big Data
Authors: Li Xiangyang , Shen Yangyang
Published: July 2020

Discretization based on rough sets is used to divide the space formed by continuous attribute values with as few breakpoint sets as possible, while maintaining the original indistinguishable relationship of the decision system, so as to accurately classify and identify related information. In this study, a discretization algorithm for incomplete economic information in rough set based on big data is proposed. First, the algorithm for filling-in incomplete economic information based on deep learning is used to supplement the incomplete economic information. Then, based on breakpoint discrimination, the algorithm for discretization in the rough set is used to implement the discretization based on rough set for supplementary economic information. The performance of this algorithm was tested using multiple sets of data and compared with other algorithms. Experimental results show that this algorithm is effective for discretization based on a rough set of incomplete economic information. When the number of incomplete economic information rough candidate breakpoints increases, it still has a higher computational efficiency and can effectively improve the integrity of incomplete economic information, and finally the application performance is superior.
Research on Stress Characteristics of Segment Structure during the Construction of the Large-Diameter Shield Tunnel and Cross-Passage
Authors: Tan Zhongsheng , Li Zonglin , Tang Wei , Chen Xueying , Duan Junmeng
Published: July 2020

With the intensive development of China’s high-speed railway network and intercity railway network, the construction of the large-diameter shield tunnels and cross-passages is gradually increasing. The construction of large diameter shield tunnels and the excavation of cross-passages puts forward higher requirements for the stability and safety of segment structure. Based on the Wangjing tunnel project, this paper studies the segment displacement and mechanical response of the shield tunnel with a diameter of 10.5 m in the process of shield construction and cross-passage construction. The results show that during the construction of large diameter shield tunnels, the vault and invert produce inward displacement, the invert uplift usually is more severe than the vault settlement, and the arch waist on both sides produces outward displacement. Near the segment K (capping block), the mechanical performance of the segment is close to that of the hinge or chain rod, which can only effectively transmit the axial force but cannot resist the bending moment and shear force. During construction of the cross-passage, the maximum deformation and stress of shield tunnel segment are symmetrically located at the interface of the main tunnel and cross-passage. The upper and lower edges of the segment at the interface tend to change from compression to tension. At the same time, the steel bars on the inside and outside of the segment vault and the arch waist change from compressive stress to tensile stress, which can easily lead to segment damage, so these positions can be reinforced by erecting section steel frames before construction.
Binary Neutron Star Merger Simulations with a Calibrated Turbulence Model
Authors: Radice David
Published: July 2020

Magnetohydrodynamic (MHD) turbulence in neutron star (NS) merger remnants can impact their evolution and multi-messenger signatures, complicating the interpretation of present and future observations. Due to the high Reynolds numbers and the large computational costs of numerical relativity simulations, resolving all the relevant scales of the turbulence will be impossible for the foreseeable future. Here, we adopt a method to include subgrid-scale turbulence in moderate resolution simulations by extending the large-eddy simulation (LES) method to general relativity (GR). We calibrate our subgrid turbulence model with results from very-high-resolution GRMHD simulations, and we use it to perform NS merger simulations and study the impact of turbulence. We find that turbulence has a quantitative, but not qualitative, impact on the evolution of NS merger remnants, on their gravitational wave signatures, and on the outflows generated in binary NS mergers. Our approach provides a viable path to quantify uncertainties due to turbulence in NS mergers.
Prenatal Visual Exposure to a Predator Influences Lateralization in Goldbelly Topminnows
Authors: Dadda Marco , Vendramin Veronica , Agrillo Christian
Published: July 2020

The role of genetic and environmental factors in modulating the development of brain lateralization is far from being fully understood, and the presence of individual differences in several lateralized functions is still an open question. In goldbelly topminnows, the genetic basis of asymmetrical functions in the brain has been studied, and recently it has been found that light stimulation influences the expression of lateralization of newborns. Here, we investigated whether prenatal exposure to predators affects the development of lateralization in 10-day-old topminnows born from females exposed to a real or to a simulated predator during pregnancy. Offspring from females exposed to a real predator were lateralized in both visual and motor tests, whereas fish from females exposed to a simulated predator were not and did not differ from controls. Prenatal exposure to a real predator might promote the alignment of lateralization in the same direction in different individuals.
Astrocytes Are More Vulnerable than Neurons to Silicon Dioxide Nanoparticle Toxicity in Vitro
Authors: Limón-Pacheco Jorge Humberto , Jiménez-Barrios Natalie , Déciga-Alcaraz Alejandro , Martínez-Cuazitl Adriana , Mata-Miranda Mónica Maribel , Vázquez-Zapién Gustavo Jesús , Pedraza-Chaverri Jose , Chirino Yolanda Irasema , Orozco-Ibarra Marisol
Published: July 2020

Some studies have shown that silicon dioxide nanoparticles (SiO2-NPs) can reach different regions of the brain and cause toxicity; however, the consequences of SiO2-NPs exposure on the diverse brain cell lineages is limited. We aimed to investigate the neurotoxic effects of SiO2-NP (0–100 µg/mL) on rat astrocyte-rich cultures or neuron-rich cultures using scanning electron microscopy, Attenuated Total Reflection-Fourier Transform Infrared spectroscopy (ATR-FTIR), FTIR microspectroscopy mapping (IQ mapping), and cell viability tests. SiO2-NPs were amorphous particles and aggregated in saline and culture media. Both astrocytes and neurons treated with SiO2-NPs showed alterations in cell morphology and changes in the IR spectral regions corresponding to nucleic acids, proteins, and lipids. The analysis by the second derivative revealed a significant decrease in the signal of the amide I (α-helix, parallel β-strand, and random coil) at the concentration of 10 µg/mL in astrocytes but not in neurons. IQ mapping confirmed changes in nucleic acids, proteins, and lipids in astrocytes; cell death was higher in astrocytes than in neurons (10–100 µg/mL). We conclude that astrocytes were more vulnerable than neurons to SiO2-NPs toxicity. Therefore, the evaluation of human exposure to SiO2-NPs and possible neurotoxic effects must be followed up.
An Enhanced Approach to the Spatial and Statistical Analysis of Factors Influencing Spring Distribution on a Transboundary Karst Aquifer
Authors: Iván Veronika , Stevenazzi Stefania , Pollicino Licia C. , Masetti Marco , Mádl-Szőnyi Judit
Published: July 2020

Karst aquifers are indispensable, yet vulnerable, resources; therefore, they require a comprehensive protection strategy. Since springs are the terminal points of the karst flow systems, knowledge of their distribution is a key element for the better understanding of groundwater flow, availability and vulnerability. The present study aims to introduce a data-driven analysis by the application of a spatial statistical technique (Weights of Evidence (WofE)) for the evaluation of factors influencing spring distribution in karst areas. A workflow was developed for investigating two questions: where will the springs locate, and where will the permanent springs evolve? This workflow has the potential for application to unconfined karst areas. This enhanced approach was applied to an unconfined transboundary aquifer, the Gömör–Torna Karst (HU and SK). The roles of five factors was statistically investigated: terrain elevation, distance to faults, distance of the carbonate–non-carbonate rock contact, distance to sinkholes, and precipitation distribution. The validation procedures confirmed the effectiveness of the approach. The resulting predictive maps are useful for decision-makers to delineate areas holding potential karst springs and to address water availability problems and protection measures. In addition, the WofE technique improved the comprehension of the geological conditions favourable for the formation of the springs.
Combining Water Quality Indices and Multivariate Modeling to Assess Surface Water Quality in the Northern Nile Delta, Egypt
Authors: Gad Mohamed , Elsayed Salah , Moghanm Farahat S. , Almarshadi Mohammed H. , Alshammari Abdullah S. , Khedher Khaled M. , Eid Ebrahem M. , Hussein Hend
Published: July 2020

Assessing surface water quality for drinking use in developing countries is important since water quality is a fundamental aspect of surface water management. This study aims to improve surface water quality assessments and their controlling mechanisms using the drinking water quality index (DWQI) and four pollution indices (PIs), which are supported by multivariate statistical analyses, such as principal component analysis, partial least squares regression (PLSR), and stepwise multiple linear regression (SMLR). Twenty-two physicochemical parameters were analyzed using standard analytical methods for 55 surface water sites in the northern Nile Delta, Egypt. The DWQI results indicated that 33% of the tested samples represented good water, and 67% of samples indicated poor to unsuitable water for drinking use. The PI results revealed that surface water samples were strongly affected by Pb and Mn and were slightly affected by Fe and Cr. The SMLR models of the DWQI and PIs, which were based on all major ions and heavy metals, provided the best estimations with R2 = 1 for the DWQI and PIs. In conclusion, integration between the DWQI and PIs is a valuable and applicable approach for the assessment of surface water quality, and the PLSR and SMLR models can be used through applications of chemometric techniques to evaluate the DWQI and PIs.
Pandemia y/o pandemónium. Encrucijadas de la salud pública latinoamericana en un mundo global
Authors: Sojo Ana
Published: July 2020

Este documento de trabajo aborda, en primer lugar, los graves pronósticos realizados en el último decenio acerca de los riesgos pandémicos, y el sombrío diagnóstico sobre la falta de preparación de los países para encararlos. En segundo lugar, realiza un breve contrapunto de las capacidades que se preveía que tendrían los países, con su trayectoria efectiva respecto de la COVID-19. Finalmente, se analizan las estrechas ven-tanas de intervención temprana relacionadas con las características del virus, y algunos problemas de go-bernanza sistémica para combatirlo, con énfasis en América Latina, pero desde una perspectiva global.
PROSPECTS FOR THE APPLICATION OF LASER SURFACE TECHNOLOGY FOR RESTORING ROLLERS OF CONTINUOUS CASTING MACHINES
Authors: Makarov A. , Kudryashov A. , Nevezhin S. , Gerasimov A. , Vladimirov A. , Avdeeva N.
Published: July 2020

The article considers the possibility of applying laser cladding technology to restore the rollers of continuous casting machines. Effective methods of restorative surfacing of rollers of continuous casting machines are briefly presented. The paper describes the process of forming coatings for rollers using laser and electric arc surfacing methods. Laboratory equipment for preparing experimental samples for metallographic studies is described. The method of preparation of laboratory samples of coatings obtained by laser and electric arc surfacing is described. Electric arc surfacing of 20X13 steel samples is performed with PP-NP-25X5FMS powder wire. Laser surfacing of samples made of 20X13 steel is performed with an economically alloyed powder based on Fe-Co-Cr-Mo iron. The structure and composition of surfaced coatings by electric arc and laser surfacing methods for rollers of continuous casting machines are studied. The mechanical properties of the applied coatings for the rollers are studied. Tribological characteristics of coatings applied by electric arc and laser surfacing methods are investigated. To evaluate the properties of coatings, a structural and phase analysis is performed, and the friction coefficients and wear rate are determined. Graphic images of the deposited layer structures are presented. The dependences of the friction coefficient of the deposited layers are presented and their differences for each of the surfacing methods are analyzed. An explanation of the differences in the properties of coatings based on the analysis of their formation conditions is offered. The efficiency of using the laser surfacing method for restoring parts of metallurgical equipment is evaluated.
CONSIDERATION OF INTERESTS OF HOMS RESIDENTS WHEN RENOVATING A RESIDENTIAL BUILDING AFTER DESTRUCTION
Authors: Alekseev Yu. , Mourad Alashkar E. H. , Rukosueva E. , Majorzadehzahiri A.
Published: July 2020

The war disrupted the life of the city, destroyed the social, economic and environmental spheres in Homs. A sociological study – a questionnaire survey of city residents is conducted to understand in which direction to carry out the planning process and what activities should be taken into account when planning the territory of the city of Homs. As a result of the survey and data analysis, tables are developed that include internal and external factors and affect the spatial development of the city of Homs. Matrices for assessing internal factors (IFE) and external factors (EFE) are compiled by SWOT analysis. The planning possibilities and limitations that provide reasonable planning of the city of Homs are identified and analyzed. The results obtained indicate that the resource potential of the territory is quite rich and can eliminate weaknesses, overcome external threats and strengthen the planning system to ensure the sustainable development of Homs. An optimal strategy for the spatial development of the city is proposed. It is described by groups of internal and external factors. It takes into account socio-cultural and economic aspects, environmental aspects and the management of spatial and territorial development of territories.
COMPOSITE BINDERS BASED ON CONCRETE SCRAP
Authors: Ahmed A. , Lesovik R. , Al Mamouri S. , Gunchenko T.
Published: July 2020

The object of research is composite binders obtained from concrete scrap of destroyed buildings and structures for the production of various construction products and structures. Fractions of concrete scrap of 0,0–0,16 mm and 0,16–0,315 mm are used, since x-rayphase analysis of various fractions of concrete scrap shows that these fractions have the highest content of non-hydrated particles of alite and belite. The influence of the specific surface area on the normal density of cement dough and the setting time of binders is established. Comparative physical and mechanical indicators of hardening of binders with different specific surfaces indicate that the most stable results with a uniform increase in strength is the composition of a binder with a specific surface of 964 m2 / kg, with an increase in strength from 2 to 7 days – 27 % and from 7 to 28 days – 21 %. This binder is characterized by optimal strength at the age of 28 days – 25,5 MPa. With a specific surface of 964 m2/kg, the best conditions are created for the formation of the primary frame and its further fouling with various calcium crystalline hydrates, which ensure optimal density and strength. This composite binder has a specific surface area of 964 m2/kg and is more energyefficient. Composite binders obtained in a vibration mill from concrete scrap fractions (0,0–0,16 and 0,16–0,315 mm) meet the requirements of normative documentation on setting time and physico-mechanical parameters, which allows to recommend them for use as binders in the production of construction products and structures for various purposes.
Epidemics modeling
Authors: Knopov P. , Bogdanov O.
Published: July 2020

Introduction. Due to the spread of COVID-19 in the world, mathematical modeling of epidemiological processes is an important and relevant scientific problem. There are many models describing the dynamics of pandemics, such as the standard SIR model, but most of them are deterministic, while in reality, the processes of infecting and recoveries are random in nature. Also, most of the models either do not include the existence of vaccines or medication or do not take into consideration the price of such medication. Sometimes, because of the high price, the widespread use of contemporary medication is impossible, especially in poor countries. In this case, there is a problem of finding a compromise between the purchase of a low amount of medication and a low amount of human deaths as a result of a pandemic. We propose a stochastic model, which describes this situation.

The purpose of the paper is to develop a mathematical model corresponding to the minimization of losses from certain pandemics, as well as the analysis of such a model.

Results. In this paper, we propose a stochastic model that describes the behavior of an epidemic with a certain amount of medication administered among the population. We present several estimates for the parameters of the epidemic, such as its duration and the total number of infected people at a certain time, given an initial number of infected people. The first two moments of the number of infected people at a given time were found. Furthermore, we found an estimate of the total losses as a result of the pandemic, which includes medication costs and losses from deaths. Several formulas are presented, which simplify the search for the minimal amount of medication needed to minimize the losses.

Conclusions. The presented problem and its solution can be used for models of certain epidemics to minimize the medication costs and losses from deaths.

Keywords: epidemic, epidemic modeling, loss minimization.