bluuebunny/crossref_metadata_2025 huggingface dataset:
Collective Motion of Repulsive Brownian Particles in Single-File Diffusion with and without Overtaking
Authors: Ooshida Takeshi , Goto Susumu , Otsuki Michio
Published: August 2018

Subdiffusion is commonly observed in liquids with high density or in restricted geometries, as the particles are constantly pushed back by their neighbors. Since this “cage effect” emerges from many-body dynamics involving spatiotemporally correlated motions, the slow diffusion should be understood not simply as a one-body problem but as a part of collective dynamics, described in terms of space–time correlations. Such collective dynamics are illustrated here by calculations of the two-particle displacement correlation in a system of repulsive Brownian particles confined in a (quasi-)one-dimensional channel, whose subdiffusive behavior is known as the single-file diffusion (SFD). The analytical calculation is formulated in terms of the Lagrangian correlation of density fluctuations. In addition, numerical solutions to the Langevin equation with large but finite interaction potential are studied to clarify the effect of overtaking. In the limiting case of the ideal SFD without overtaking, correlated motion with a diffusively growing length scale is observed. By allowing the particles to overtake each other, the short-range correlation is destroyed, but the long-range weak correlation remains almost intact. These results describe nested space–time structure of cages, whereby smaller cages are enclosed in larger cages with longer lifetimes.
Enhancing Teaching-Learning Effectiveness by Creating Online Interactive Instructional Modules for Fundamental Concepts of Physics and Mathematics
Authors: Moradi Moein , Liu Lin , Luchies Carl , Patterson Meagan M. , Darban Behnaz
Published: August 2018

This study explored the effectiveness of online instructional modules for providing supplementary instruction in basic mathematics and physics concepts. The modules were developed in accordance with a cognitive apprenticeship model. Participants (N = 47) were students enrolled in a required Statics course at a midwestern university. Participants were randomly assigned to either an intervention or control group. The results show that the intervention group performed significantly better on post-tests through using the online instructional modules, while there was no significant improvement of performance in the control group. Based on survey results, students expressed their engagement to the instructional materials. Furthermore, they expressed a self-paced learning experience through providing feedback that they had control over the course materials by using the developed online instructional modules. Survey results also were indicative of students’ approval of using the modules as a supplemental material to classroom lectures.
On the Concept of Context
Authors: Dohn Nina Bonderup , Hansen Stig Børsen , Klausen Søren Harnow
Published: August 2018

This article aims to clarify the concept of context. Our motivation is the lack of consensus on what context is, despite common accept of the claim that learning is context-dependent to some degree, and despite a widespread interest in researching learning in specific contexts such as museums, classrooms, or workplace settings. We provide a minimal concept which is applicable to all references to context, properly construed. We point out that more general considerations of contextuality and compositionality must be reconciled and balanced out if the role of context in relation to learning is to be understood. We then flesh out the minimal concept with a typology of context categories relevant for understanding the significance of context for learning. The categories are location, understood both in a physical-geographical and an institutional sense, knowledge domain, sequence of occurrences, activity, historical period, social relationship, and horizon of significance. We illustrate the usefulness of the typology through pointing out how it could help clarify discussions about transfer of knowledge and skills.
Analysis of the Quantization Noise in Discrete Wavelet Transform Filters for Image Processing
Authors: Chervyakov Nikolay , Lyakhov Pavel , Kaplun Dmitry , Butusov Denis , Nagornov Nikolay
Published: August 2018

In this paper, we analyze the noise quantization effects in coefficients of discrete wavelet transform (DWT) filter banks for image processing. We propose the implementation of the DWT method, making it possible to determine the effective bit-width of the filter banks coefficients at which the quantization noise does not significantly affect the image processing results according to the peak signal-to-noise ratio (PSNR). The dependence between the PSNR of the DWT image quality on the wavelet and the bit-width of the wavelet filter coefficients is analyzed. The formulas for determining the minimal bit-width of the filter coefficients at which the processed image achieves high quality (PSNR ≥ 40 dB) are given. The obtained theoretical results were confirmed through the simulation of DWT for a test image using the calculated bit-width values. All considered algorithms operate with fixed-point numbers, which simplifies their hardware implementation on modern devices: field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), etc.
Variants of the Low-Energy Adaptive Clustering Hierarchy Protocol: Survey, Issues and Challenges
Authors: Al-Shalabi Mohammed , Anbar Mohammed , Wan Tat-Chee , Khasawneh Ahmad
Published: August 2018

A wireless sensor network (WSN) is a modern technology in radio communication. A WSN comprises a number of sensors that are randomly spread in a specific area for sensing and monitoring physical attributes that are difficult to monitor by humans, such as temperature, humidity, and pressure. Many problems, including data routing, power consumption, clustering, and selecting cluster heads (CHs), may occur due to the nature of WSNs. Various protocols have been conducted to resolve these issues. One of the important hierarchical protocols that are used to reduce power consumption in WSNs is low-energy adaptive clustering hierarchy (LEACH). This paper presents a comprehensive study of clustering protocols for WSNs that are relevant to LEACH. This paper is the first to emphasis on cluster formation and CHs selection methods and their strengths and weaknesses. A new taxonomy is presented to discuss LEACH variants on the basis of different classes, and the current survey is compared with other existing surveys. A complete comparison of the location, energy, complexity, reliability, multi–hop path, and load balancing characteristics of LEACH variants is conducted. Future research guidelines for CHs selection and cluster formation in WSNs are also discussed.
Precision Modeling: Application of Metaheuristics on Current–Voltage Curves of Superconducting Films
Authors: Naqvi Syed Rameez , Akram Tallha , Haider Sajjad Ali , Kamran Muhammad , Shahzad Aamir , Khan Wilayat , Iqbal Tassawar , Umer Hafiz Gulfam
Published: August 2018

Contemplating the importance of studying current–voltage curves in superconductivity, it has been recently and rightly argued that their approximation, rather than incessant measurements, seems to be a more viable option. This especially becomes bona fide when the latter needs to be recorded for a wide range of critical parameters including temperature and magnetic field, thereby becoming a tedious monotonous procedure. Artificial neural networks have been recently put forth as one methodology for approximating these so-called electrical measurements for various geometries of antidots on a superconducting thin film. In this work, we demonstrate that the prediction accuracy, in terms of mean-squared error, achieved by artificial neural networks is rather constrained, and, due to their immense credence on randomly generated networks’ coefficients, they may result in vastly varying prediction accuracies for different geometries, experimental conditions, and their own tunable parameters. This inconsistency in prediction accuracies is resolved by controlling the uncertainty in networks’ initialization and coefficients’ generation by means of a novel entropy based genetic algorithm. The proposed method helps in achieving a substantial improvement and consistency in the prediction accuracy of current–voltage curves in comparison to existing works, and is amenable to various geometries of antidots, including rectangular, square, honeycomb, and kagome, on a superconducting thin film.
Stream Data Cleaning for Dynamic Line Rating Application
Authors: Nemati Hassan , Laso A. , Manana M. , Sant'Anna Anita , Nowaczyk Sławomir
Published: August 2018

The maximum current that an overhead transmission line can continuously carry depends on external weather conditions, most commonly obtained from real-time streaming weather sensors. The accuracy of the sensor data is very important in order to avoid problems such as overheating. Furthermore, faulty sensor readings may cause operators to limit or even stop the energy production from renewable sources in radial networks. This paper presents a method for detecting and replacing sequences of consecutive faulty data originating from streaming weather sensors. The method is based on a combination of (a) a set of constraints obtained from derivatives in consecutive data, and (b) association rules that are automatically generated from historical data. In smart grids, a large amount of historical data from different weather stations are available but rarely used. In this work, we show that mining and analyzing this historical data provides valuable information that can be used for detecting and replacing faulty sensor readings. We compare the result of the proposed method against the exponentially weighted moving average and vector autoregression models. Experiments on data sets with real and synthetic errors demonstrate the good performance of the proposed method for monitoring weather sensors.
Short-Term Load Forecasting of Natural Gas with Deep Neural Network Regression †
Authors: Merkel Gregory D. , Povinelli Richard J. , Brown Ronald H.
Published: August 2018

Deep neural networks are proposed for short-term natural gas load forecasting. Deep learning has proven to be a powerful tool for many classification problems seeing significant use in machine learning fields such as image recognition and speech processing. We provide an overview of natural gas forecasting. Next, the deep learning method, contrastive divergence is explained. We compare our proposed deep neural network method to a linear regression model and a traditional artificial neural network on 62 operating areas, each of which has at least 10 years of data. The proposed deep network outperforms traditional artificial neural networks by 9.83% weighted mean absolute percent error (WMAPE).
Reinforcement Learning Based Energy Management Algorithm for Smart Energy Buildings
Authors: Kim Sunyong , Lim Hyuk
Published: August 2018

A smart grid facilitates more effective energy management of an electrical grid system. Because both energy consumption and associated building operation costs are increasing rapidly around the world, the need for flexible and cost-effective management of the energy used by buildings in a smart grid environment is increasing. In this paper, we consider an energy management system for a smart energy building connected to an external grid (utility) as well as distributed energy resources including a renewable energy source, energy storage system, and vehicle-to-grid station. First, the energy management system is modeled using a Markov decision process that completely describes the state, action, transition probability, and rewards of the system. Subsequently, a reinforcement-learning-based energy management algorithm is proposed to reduce the operation energy costs of the target smart energy building under unknown future information. The results of numerical simulation based on the data measured in real environments show that the proposed energy management algorithm gradually reduces energy costs via learning processes compared to other random and non-learning-based algorithms.
Estimation of Load Pattern for Optimal Planning of Stand-Alone Microgrid Networks
Authors: Lee Chang Koo , Bhang Byeong Gwan , Kim David Kwangsoon , Lee Sang Hun , Cha Hae Lim , Ahn Hyung Keun
Published: August 2018

This paper proposes a method for estimating the load pattern for optimal planning of stand-alone renewable microgrids and verifies when the basic data for microgrid design are limited. To estimate a proper load pattern for optimal microgrid design when the data obtained in advance are insufficient, the least squares method is used to compare the similarity of annual power consumption between the subject area and eight islands in Korea whose actual load patterns were previously obtained. Similarity is compared in terms of annual (every month), seasonal, bi-monthly, and monthly averages. To verify the validity of the proposed estimation method, the applied proposed estimation method is used for two islands that have already installed a microgrid consisting of photovoltaic, wind power, energy storage systems, and diesel generators. In comparing the actual data from the two islands, the costs of electricity in terms of microgrid operations show improvements of 37.2% and 29.8%, respectively.
Technological Solutions for Recycling Ash Slag from the Cao Ngan Coal Power Plant in Vietnam
Authors: Thenepalli Thriveni , Ngoc Nguyen Thi Minh , Tuan Lai Quang , Son Trinh Hai , Hieu Ho Huu , Thuy Dang Tran Nhu , Thao Nguyen Thi Thanh , Tam Duong Thi Thanh , Huyen Doan Thi Ngoc , Van Tran Tan , Chilakala Ramakrishna , Ahn Ji Whan
Published: August 2018

Annually, coal-fired power plants in Vietnam discharge hundreds of thousand tons of coal ash. Most of this ash goes into the environment without treatment or any plan for the efficient reuse of this precious resource. There are many reasons for this, such as poor quality of the ash, no suitable and feasible ash treatment technology, a lack of awareness about environmental pollution and resource saving, and inappropriate sanctions and policies. This study analyzed and summarized information and data pertaining to the current status of the production, discharge, and utilization of coal ash from the Cao Ngan Power Plant (CNPP) in Thai Nguyen Province, Vietnam. In addition, the potential for applying advanced emission reduction technologies in order to recycle coal ash for cement production, as well as geographical, socio-economic, and market factors were assessed. This paper reveals the results of a preliminary assessment of carbon-mineralization technologies which seek to achieve the following three goals: (1) effectively disposing of coal ash to protect the environment and local community, (2) contributing to the nationally determined effort to mitigate greenhouse gas emissions which cause climate change, and (3) making value-added products and bringing economic benefits to a sustainable society.
Pilot Protection Based on Amplitude of Directional Travelling Wave for Voltage Source Converter-High Voltage Direct Current (VSC-HVDC) Transmission Lines
Authors: Jiang Lingtong , Chen Qing , Huang Wudi , Wang Lei , Zeng Yu , Zhao Pu
Published: August 2018

This paper presents a novel pilot protection scheme of DC cable line in voltage-source-converter (VSC) based multi-terminal DC (MTDC) grids, which utilizes a novel phase-mode transformation to decouple the bipolar DC cable current into six mode and it uses the stationary wavelet transform to extract the modulus maxima of fault initial traveling waves current (FITWC). With accurate amplitude and polarities of the FITWC being collected from the fault-detection devices located at each terminal, the proposed scheme can correctly determine the faulty segment and the faulty pole. In this paper, the ratio of amplitudes between sixth mode forward and backward travelling wave currents is used to judge the faulty segment and the polarity of fifth mode forward travelling wave current is used to identify the faulty pole. A four-terminal VSC-based MTDC grid was built in PSCAD/EMTDC to evaluate the performance of the fault-protection scheme. Simulation results for different cases demonstrate that the proposed protection scheme is robust against noise, and has been tested successfully for fault resistance of up to 400 Ω. Since the scheme merely needs the characteristics of FITWCs, the practical difficulties of detecting subsequent travelling waves are avoided. Moreover, only the state signal is needed to send to the other side in proposed scheme, so low communication speed can satisfy the requirement of relay protection and it does not need the data synchronization seriously.
Hydrothermal Carbonization of Fruit Wastes: A Promising Technique for Generating Hydrochar
Authors: Zhang Bide , Heidari Mohammad , Regmi Bharat , Salaudeen Shakirudeen , Arku Precious , Thimmannagari Mahendra , Dutta Animesh
Published: August 2018

Hydrothermal carbonization (HTC) is a useful method to convert wet biomass to value-added products. Fruit waste generated in juice industries is a huge source of moist feedstock for such conversion to produce hydrochar. This paper deals with four types of fruit wastes as feedstocks for HTC; namely, rotten apple (RA), apple chip pomace (ACP), apple juice pomace (AJP), and grape pomace (GP). The operating conditions for HTC processing were 190 °C, 225 °C, and 260 °C for 15 min. For all samples, higher heating value and fixed carbon increased, while volatile matter and oxygen content decreased after HTC. Except for ACP, the ash content of all samples increased after 225 °C. For RA, AJP, and GP, the possible explanation for increased ash content above 225 °C is that the hydrochar increases in porosity after 230 °C. It was observed that an increase in HTC temperature resulted in an increase in the mass yield for RA and GP, which is in contrast with increasing HTC temperature for lignocellulose biomass. Other characterization tests like thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) also showed that the HTC process can be successfully used to convert fruit wastes into valuable products.
Coupled Fluid-Thermal Analysis for Induction Motors with Broken Bars Operating under the Rated Load
Authors: Xie Ying , Guo Jinpeng , Chen Peng , Li Zhiwei
Published: August 2018

Thermal stress of the rotor in a squirrel cage induction motor is generated due to the temperature rise, it is also one of the factors causing the broken bar fault because the structure of the rotor would be destroyed if the stress of the rotor bars exceed the strength limit. The coupled fluid-thermal analysis for the induction motor with healthy and broken bar rotors is performed in this paper. Much concern has been committed to establishment of the fluid model on the basis of computational fluid dynamic (CFD) theory. The heat field of the prototypes is analysed so that the effect of the asymmetrical rotor on the motor heat performance can be investigated in depth. Eventually, the efficiency of the presented model and method, for the totally enclosed fan cooled (TEFC) induction motor, can be verified through experimental results. In addition, this paper reports a quantitative analysis of the heat flux distribution of the fault rotor, and the heat flux density of the bars is investigated in detail. Then, the part most likely to break in the rotor as a result of the thermal load is identified.
Robust Design of a Low-Cost Permanent Magnet Motor with Soft Magnetic Composite Cores Considering the Manufacturing Process and Tolerances
Authors: Liu Chengcheng , Lei Gang , Ma Bo , Guo Youguang , Zhu Jianguo
Published: August 2018

This paper uses the Taguchi method to optimize the manufacturing process and robust design of a low-cost permanent magnet motor with soft magnetic composite (SMC) cores. For the manufacturing process, SMC cores are produced by using the molding technology without any wire cutting costs. To maximize the relative permeability and minimize the core loss, the Taguchi method is employed to identify the best control factor values for the heat treatment of SMC cores based on a series of experimental results. Due to the manufacturing tolerances, there are significant uncertainties in the core densities and motor dimensions, which will result in big performance variations for the SMC motors in the batch production. To obtain a robust design less sensitive to these tolerances, the conventional Taguchi parameter design method and a sequential Taguchi optimization method are presented to maximize the average torque and minimize the core loss of a low-cost PM motor. Through comparison, it is found that the proposed optimization method is efficient. It can provide an optimal design with better motor performance and manufacturing quality. The proposed method will benefit the industrial production of cost-effective PM-SMC motors with robust and compact designs.
Identification of miRNAs Associated with Graft Union Development in Pecan [Carya illinoinensis (Wangenh.) K. Koch]
Authors: Mo Zhenghai , Feng Gang , Su Wenchuan , Liu Zhuangzhuang , Peng Fangren
Published: August 2018

Pecan [Carya illinoinensis (Wangenh.) K. Koch] is a high-value fruit tree with a long juvenile period. The fruiting process of pecan seedlings can be largely accelerated through grafting. As non-coding small RNAs, plant miRNAs participate in various biological processes through negative regulation of gene expression. To reveal the roles of miRNAs in the graft union development of pecan, four small RNA libraries were constructed from the graft union at days 0, 8, 15, and 30 after grafting. A total of 47 conserved miRNAs belonging to 31 families and 39 novel miRNAs were identified. For identified miRNAs, 584 target genes were bioinformatically predicted, and 266 of them were annotated; 29 miRNAs (including 16 conserved and 13 novel miRNAs) were differentially expressed during the graft process. The expression profiles of 12 miRNA were further validated by quantitative reverse transcription PCR (qRT-PCR). In addition, qRT-PCR revealed that the expression levels of 3 target genes were negatively correlated with their corresponding miRNAs. We found that miRS26 might be involved in callus formation; miR156, miR160, miR164, miR166, and miRS10 might be associated with vascular bundle formation. These results indicate that the miRNA-mediated gene regulations play important roles in the graft union development of pecan.
Genomic Diversity of Listeria monocytogenes Isolated from Clinical and Non-Clinical Samples in Chile
Authors: Toledo Viviana , Den Bakker Henk C. , Hormazábal Juan Carlos , González-Rocha Gerardo , Bello-Toledo Helia , Toro Magaly , Moreno-Switt Andrea I.
Published: August 2018

Listeria monocytogenes is the causative agent of listeriosis, which is an uncommon but severe infection associated with high mortality rates in humans especially in high-risk groups. This bacterium survives a variety of stress conditions (e.g., high osmolality, low pH), which allows it to colonize different niches especially niches found in food processing environments. Additionally, a considerable heterogeneity in pathogenic potential has been observed in different strains. In this study, 38 isolates of L. monocytogenes collected in Chile from clinical samples (n = 22) and non-clinical samples (n = 16) were analyzed using whole genome sequencing (WGS) to determine their genomic diversity. A core genome Single Nucleotide Polymorphism (SNP) tree using 55 additional L. monocytogenes accessions classified the Chilean isolates in lineages I (n = 25) and II (n = 13). In silico, Multi-locus sequence typing (MLST) differentiated the isolates into 13 sequence types (ST) in which the most common were ST1 (15 isolates) and ST9 (6 isolates) and represented 55% of the isolates. Genomic elements associated with virulence (i.e., LIPI-1, LIPI-3, inlA, inlB, inlC, inlG, inlH, inlD, inlE, inlK, inlF, and inlJ) and stress survival (i.e., stress survival islet 1 and stress survival islet 2) were unevenly distributed among clinical and non-clinical isolates. In addition, one novel inlA premature stop codon (PMSC) was detected. Comparative analysis of L. monocytogenes circulating in Chile revealed the presence of globally distributed sequence types along with differences among the isolates analyzed at a genomic level specifically associated with virulence and stress survival.
Multi-Wavelength High-Resolution Spectroscopy for Exoplanet Detection: Motivation, Instrumentation and First Results
Authors: Benatti Serena
Published: August 2018

Exoplanet research has shown an incessant growth since the first claim of a hot giant planet around a solar-like star in the mid-1990s. Today, the new facilities are working to spot the first habitable rocky planets around low-mass stars as a forerunner for the detection of the long-awaited Sun-Earth analog system. All the achievements in this field would not have been possible without the constant development of the technology and of new methods to detect more and more challenging planets. After the consolidation of a top-level instrumentation for high-resolution spectroscopy in the visible wavelength range, a huge effort is now dedicated to reaching the same precision and accuracy in the near-infrared. Actually, observations in this range present several advantages in the search for exoplanets around M dwarfs, known to be the most favorable targets to detect possible habitable planets. They are also characterized by intense stellar activity, which hampers planet detection, but its impact on the radial velocity modulation is mitigated in the infrared. Simultaneous observations in the visible and near-infrared ranges appear to be an even more powerful technique since they provide combined and complementary information, also useful for many other exoplanetary science cases.
Where Children Play: Young Child Exposure to Environmental Hazards during Play in Public Areas in a Transitioning Internally Displaced Persons Community in Haiti
Authors: Medgyesi Danielle N. , Brogan John M. , Sewell Daniel K. , Creve-Coeur Jean Philippe , Kwong Laura H. , Baker Kelly K.
Published: August 2018

Globally, gastrointestinal (GI) infections by enteric pathogens are the second-leading cause of morbidity and mortality in children under five years of age (≤5 years). While GI pathogen exposure in households has been rigorously examined, there is little data about young children’s exposure in public domains. Moreover, public areas in low-income settings are often used for other waste disposal practices in addition to human feces, such as trash dumping in areas near households. If young children play in public domains, they might be exposed to interrelated and highly concentrated microbial, chemical, and physical hazards. This study performed structured observations at 36 public areas in an internally displaced persons community that has transitioned into a formal settlement in Haiti. We documented how often young children played in public areas and quantified behaviors that might lead to illness and injury. Children ≤5 years played at all public sites, which included infants who played at 47% of sites. Children touched and mouthed plastic, metal and glass trash, food and other objects from the ground, ate soil (geophagia) and drank surface water. They also touched latrines, animals, animal feces and open drainage canals. Hand-to-mouth contact was one of the most common behaviors observed and the rate of contact significantly differed among developmental stages (infants: 18/h, toddlers: 11/h and young children: 9/h), providing evidence that children could ingest trace amounts of animal/human feces on hands that may contain GI pathogens. These findings demonstrate that water, sanitation and hygiene interventions could be more effective if they consider exposure risks to feces in public domains. Furthermore, this research highlights the need for waste-related interventions to address the broader set of civil conditions that create unsafe, toxic and contaminated public environments where young children play.
Applications of Distress Prediction Models: What Have We Learned After 50 Years from the Z-Score Models?
Authors: Altman Edward I.
Published: August 2018

Fifty years ago, I published the initial, classic version of the Z-score bankruptcy prediction models. This multivariate statistical model has remained perhaps the most well-known, and more importantly, most used technique for providing an early warning signal of firm financial distress by academics and practitioners on a global basis. It also has been used by scholars as a benchmark of credit risk measurement in countless empirical studies. Practical applications of the Altman Z-score model have also been numerous and can be divided into two main categories: (1) from an external analytical standpoint, and (2) from an internal to the distressed firm viewpoint. This paper discusses a number of applications from the former’s standpoint and in doing so, we hope, also provides a roadmap for extensions beyond those already identified.
Multi-Temporal Image Analysis for Fluvial Morphological Characterization with Application to Albanian Rivers
Authors: Spada Daniele , Molinari Paolo , Bertoldi Walter , Vitti Alfonso , Zolezzi Guido
Published: August 2018

A procedure for the characterization of the temporal evolution of river morphology is presented. Wet and active river channels are obtained from the processing of imagery datasets. Information about channel widths and active channel surface subdivision in water, vegetation and gravel coverage classes are evaluated along with channel centerline lengths and sinuosity indices. The analysis is carried out on a series of optical remotely-sensed imagery acquired by different satellite missions during the time period between 1968 and 2017. Data from the CORONA, LANDSAT and Sentinel-2 missions were considered. Besides satellite imagery, a digital elevation model and aerial ortho-photos were also used. The procedure was applied to three, highly dynamic, Albanian rivers: Shkumbin, Seman and Vjosë, showing a high potential for application in contexts with limitations in ground data availability. The results of the procedure were assessed against reference data produced by means of expert interpretation of a reference set of river reaches. The results differ from reference values by just a few percentage points (<6%). The time evolution of hydromorphological parameters is well characterized, and the results support the design of future studies aimed at the understanding of the relations between climatic and anthropogenic controls and the response of river morphological trajectories. Moreover, the high spatial and temporal resolution of the Sentinel-2 mission motivates the development of an automatic monitoring system based on a rolling application of the defined procedure.
Improving Tree Species Classification Using UAS Multispectral Images and Texture Measures
Authors: Gini Rossana , Sona Giovanna , Ronchetti Giulia , Passoni Daniele , Pinto Livio
Published: August 2018

This paper focuses on the use of ultra-high resolution Unmanned Aircraft Systems (UAS) imagery to classify tree species. Multispectral surveys were performed on a plant nursery to produce Digital Surface Models and orthophotos with ground sample distance equal to 0.01 m. Different combinations of multispectral images, multi-temporal data, and texture measures were employed to improve classification. The Grey Level Co-occurrence Matrix was used to generate texture images with different window sizes and procedures for optimal texture features and window size selection were investigated. The study evaluates how methods used in Remote Sensing could be applied on ultra-high resolution UAS images. Combinations of original and derived bands were classified with the Maximum Likelihood algorithm, and Principal Component Analysis was conducted in order to understand the correlation between bands. The study proves that the use of texture features produces a significant increase of the Overall Accuracy, whose values change from 58% to 78% or 87%, depending on components reduction. The improvement given by the introduction of texture measures is highlighted even in terms of User’s and Producer’s Accuracy. For classification purposes, the inclusion of texture can compensate for difficulties of performing multi-temporal surveys.
Myeloid-Derived Suppressor Cells and Pulmonary Hypertension
Authors: Bryant Andrew J. , Mehrad Borna , Brusko Todd M. , West James D. , Moldawer Lyle L.
Published: August 2018

Myeloid–derived suppressor cells (MDSCs) comprised a heterogeneous subset of bone marrow–derived myeloid cells, best studied in cancer research, that are increasingly implicated in the pathogenesis of pulmonary vascular remodeling and the development of pulmonary hypertension. Stem cell transplantation represents one extreme interventional strategy for ablating the myeloid compartment but poses a number of translational challenges. There remains an outstanding need for additional therapeutic targets to impact MDSC function, including the potential to alter interactions with innate and adaptive immune subsets, or alternatively, alter trafficking receptors, metabolic pathways, and transcription factor signaling with readily available and safe drugs. In this review, we summarize the current literature on the role of myeloid cells in the development of pulmonary hypertension, first in pulmonary circulation changes associated with myelodysplastic syndromes, and then by examining intrinsic myeloid cell changes that contribute to disease progression in pulmonary hypertension. We then outline several tractable targets and pathways relevant to pulmonary hypertension via MDSC regulation. Identifying these MDSC-regulated effectors is part of an ongoing effort to impact the field of pulmonary hypertension research through identification of myeloid compartment-specific therapeutic applications in the treatment of pulmonary vasculopathies.
Higher Risk of Intervertebral Disc Herniation among Neurosurgeons Than Neurologists: 15 Year-Follow-Up of a Physician Cohort
Authors: Huang Wen-Cheng , Kuo Chao-Hung , Wu Jau-Ching , Chen Yu-Chun
Published: August 2018

High physical activity or workload has been associated with intervertebral disc degeneration. However, there is little data on physicians’ risks of disc disease. The study aimed to investigate the incidences of spinal problems among neurologists and neurosurgeons. A cohort of neurologists and neurosurgeons was derived from Taiwan’s national research database. During the study period, the incidences of intervertebral disc herniation or spondylosis among these specialists were calculated. Another one-to-one by propensity score matched cohort, composed of neurologists and neurosurgeons, was also analyzed. A Cox regression hazard ratio (HR) model and Kaplan-Meier analysis were conducted to compare the risks and incidences. The entire cohort comprised 481 and 317 newly board-certified neurologists and neurosurgeons, respectively. During the 15 years of follow-up, neurosurgeons were approximately six-fold more likely to develop disc problems than neurologists (crude HR = 5.98 and adjusted HR = 6.08, both p < 0.05). In the one-to-one propensity-score matched cohort (317 neurologists versus 317 neurosurgeons), there were even higher risks among neurosurgeons than neurologists (crude HR = 8.15, and adjusted HR = 10.14, both p < 0.05). Neurosurgeons have a higher chance of intervertebral disc disorders than neurologists. This is potentially an occupational risk that warrants further investigation.
Towards Sustainable Machining of Inconel 718 Using Nano-Fluid Minimum Quantity Lubrication
Authors: Hegab Hussien , Kishawy Hossam A.
Published: August 2018

Difficult-to-cut materials have been widely employed in many engineering applications, including automotive and aeronautical designs because of their effective properties. However, other characteristics; for example, high hardness and low thermal conductivity has negatively affected the induced surface quality and tool life, and consequently the overall machinability of such materials. Inconel 718, is widely used in many industries including aerospace; however, the high temperature generated during machining is negatively affecting its machinability. Flood cooling is a commonly used remedy to improve machinability problems; however, government regulation has called for further alternatives to reduce the environmental and health impacts of flood cooling. This work aimed to investigate the influence of dispersed multi-wall carbon nanotubes (MWCNTs) and aluminum oxide (Al2O3) gamma nanoparticles, on enhancing the minimum quantity lubrication (MQL) technique cooling and lubrication capabilities during turning of Inconel 718. Machining tests were conducted, the generated surfaces were examined, and the energy consumption data were recorded. The study was conducted under different design variables including cutting speed, percentage of added nano-additives (wt.%), and feed velocity. The study revealed that the nano-fluids usage, generally improved the machining performance when cutting Inconel 718. In addition, it was shown that the nanotubes additives provided better improvements than Al2O3 nanoparticles.
Activity Recognition Using Gazed Text and Viewpoint Information for User Support Systems
Authors: Chiba Shun , Miyazaki Tomo , Sugaya Yoshihiro , Omachi Shinichiro
Published: August 2018

The development of information technology has added many conveniences to our lives. On the other hand, however, we have to deal with various kinds of information, which can be a difficult task for elderly people or those who are not familiar with information devices. A technology to recognize each person’s activity and providing appropriate support based on that activity could be useful for such people. In this paper, we propose a novel fine-grained activity recognition method for user support systems that focuses on identifying the text at which a user is gazing, based on the idea that the content of the text is related to the activity of the user. It is necessary to keep in mind that the meaning of the text depends on its location. To tackle this problem, we propose the simultaneous use of a wearable device and fixed camera. To obtain the global location of the text, we perform image matching using the local features of the images obtained by these two devices. Then, we generate a feature vector based on this information and the content of the text. To show the effectiveness of the proposed approach, we performed activity recognition experiments with six subjects in a laboratory environment.
Jarosite and Alunite in Ancient Terrestrial Sedimentary Rocks: Reinterpreting Martian Depositional and Diagenetic Environmental Conditions
Authors: Potter-McIntyre Sally L. , McCollom Thomas M.
Published: August 2018

Members of the alunite group are precipitated at low pH (<1 to ~4) in oxidizing environments, are unstable in circumneutral conditions, and are widespread on Mars. At Mollies Nipple in Kane County, Utah, USA, jarosite and alunite are abundant as diagenetic cements in Jurassic sandstones. This research characterizes the jarosite and alunite cements with the goal of determining their origin, and tests the hypothesis that jarosite and alunite may be more stable than the current understanding indicates is possible. Previous studies have placed the jarosite- and alunite-bearing caprock at Mollies Nipple in the Navajo Sandstone, but the presence of water-lain deposits, volcanic ash, volcanic clasts, and peloids show that it is one of the overlying Middle Jurassic units that records sea level transgressions and regressions. A paragenetic timing, established from petrographic methods, shows that much of the cement was precipitated early in a marginal marine to coastal dune depositional environment with a fluctuating groundwater table that drove ferrolysis and evolved the groundwater to a low pH. Microbial interaction was likely a large contributor to the evolution of this acidity. Jarosite and alunite are clearly more stable in natural environments than is predicted by laboratory experiments, and therefore, the Martian environments that have been interpreted as largely acidic and/or dry over geologic time may have been more habitable than previously thought.
Powder Pre-Treatment for Aerosol Deposition of Tin Dioxide Coatings for Gas Sensors
Authors: Hanft Dominik , Bektas Murat , Moos Ralf
Published: August 2018

The Aerosol Deposition (AD) method has the unique property to allow for manufacturing dense ceramic films at room temperature. As found in many publications, the deposition process is very sensitive to powder properties. In particular, powders of nano-sized particles and grains, e.g., from precipitation, are usually beyond the conventional size range of AD processability, yielding chalk-like films of low mechanical stability. Thus, the conventional AD process is limited in applicability. In this study, we try to overcome this problem by adapting the standard milling treatment of powders for improved deposition by additional temperature pre-treatment. Using commercial tin dioxide and including a temperature treatment for grain growth, makes the powder accessible to deposition. In this way, we achieve optically translucent and conductive SnO2 thick films. With the application such as a gas sensitive film as one of many possible applications for SnO2 thick-films, the sensors show excellent response to various reducing gases. This study shows one exemplary way of extending the range of adequate powder and applications for the AD method.
Reducing Porosity and Refining Grains for Arc Additive Manufacturing Aluminum Alloy by Adjusting Arc Pulse Frequency and Current
Authors: Wang Donghai , Lu Jiping , Tang Shuiyuan , Yu Lu , Fan Hongli , Ji Lei , Liu Changmeng
Published: August 2018

Coarse grains and gas pores are two main problems that limit the application of additive manufacturing aluminum alloys. To reduce porosity and refine grains, this paper presents a quantitative investigation into the effect of pulse frequency and arc current on the porosity and grains of arc additive manufacturing Al–5Si alloy. The experiment results show that pulse frequency and arc current have a significant impact on the macrostructure, microstructure, porosity, and tensile properties of the samples. Fine grains and a uniform microstructure can be obtained with low pulse frequency and low arc current as a result of the rapid cooling of the molten pool. With the increase of pulse frequency, density shows a trend that firstly escalates and attains the maximum value at 50 Hz, but later declines as a result of the relation between pores formation and gas escape. Moreover, better tensile properties can be obtained at low pulse frequency and low arc current because of the finer grains.
Development of a Photo-Crosslinking, Biodegradable GelMA/PEGDA Hydrogel for Guided Bone Regeneration Materials
Authors: Wang Yihu , Ma Ming , Wang Jianing , Zhang Weijie , Lu Weipeng , Gao Yunhua , Zhang Bing , Guo Yanchuan
Published: August 2018

Gelatin-based hydrogel, which mimics the natural dermal extracellular matrix, is a promising tissue engineering material. However, insufficient and uncontrollable mechanical and degradation properties remain the major obstacles for its application in medical bone regeneration material. Herein, we develop a facile but efficient strategy for a novel hydrogel as guided bone regeneration (GBR) material. In this study, methacrylic anhydride (MA) has been used to modify gelatin to obtain photo-crosslinkable methacrylated gelatin (GelMA). Moreover, the GelMA/PEGDA hydrogel was prepared by photo-crosslinking GelMA and PEGDA with photoinitiator I2959 under UV treatment. Compared with the GelMA hydrogel, the GelMA/PEGDA hydrogel exhibits several times stronger mechanical properties than pure GelMA hydrogel. The GelMA/PEGDA hydrogel shows a suitable degradation rate of more than 4 weeks, which is beneficial to implant in body. In vitro cell culture showed that osteoblast can adhere and proliferate on the surface of the hydrogel, indicating that the GelMA/PEGDA hydrogel had good cell viability and biocompatibility. Furthermore, by changing the quantities of GelMA, I2959, and PEGDA, the gelation time can be controlled easily to meet the requirement of its applications. In short, this study demonstrated that PEGDA enhanced the performance and extended the applications of GelMA hydrogels, turning the GelMA/PEGDA hydrogel into an excellent GBR material.
Study on Upconversion and Thermal Properties of Tm3+/Yb3+ Co-Doped La2O3-Nb2O5-Ta2O5 Glasses
Authors: Zhang Minghui , Wen Haiqin , Pan Xiuhong , Yu Jianding , Shao Hui , Ai Fei , Yu Huimei , Tang Meibo , Gai Lijun
Published: August 2018

The effect of Yb3+ ions on upconversion luminescence and thermal properties of Tm3+/Yb3+ co-doped La2O3-Nb2O5-Ta2O5 glasses has been studied. Glass transition temperature is around 740 °C, indicating high thermal stability. The effect of Yb3+ ions on the thermal stability is not obvious. Both the glass forming ability and the upconversion luminescence first increase and then decrease with the increase of Yb3+ ions. The glasses perform low glass forming ability with ΔT around 55 °C. Blue and red emissions centered around 477, 651, and 706 nm are obtained at the excitation of 976 nm laser. The upconversion luminescence mechanism is energy transfer from Yb3+ to Tm3+ mixed with two- and three- photon processes. The thermal kinetic Differential Thermal Analysis (DTA)-analysis indicates that the average activation energy first increases and then decreases with the increase of Yb3+ ions. This result can be introduced in order to improve upconversion luminescence of glasses by crystallization in the future. Tm3+/Yb3+ co-doped La2O3-Nb2O5-Ta2O5 glasses with good upconversion and thermal properties show promising applications in solid-state laser, optical temperature sensing.
Extraction Kinetics of As(V) by Aliquat-336 Using Asymmetric PVDF Hollow-Fiber Membrane Contactors
Authors: Bey Said , Semghouni Hassina , Criscuoli Alessandra , Benamor Mohamed , Drioli Enrico , Figoli Alberto
Published: August 2018

This work focuses on the study of the mass transfer of arsenic(V) through asymmetric polyvinylidene fluoride hollow-fiber membrane contactors using Aliquat-336 as an extractant. In the first part of this work, the fibers were prepared and characterized by SEM and by determining their thickness and porosity. From SEM pictures, an asymmetric structure was obtained that was characterized by an inner sponge-like structure and outer finger-like structure with a pore radius and porosity about 0.11 µm and 80%, respectively. In the second part, the prepared fibers were used as membrane contactors for the study of mass transfer of arsenic(V), investigating the effect of several parameters such as pH, temperature, and initial concentration of the feed. The overall mass transfer coefficient of As(V) was around 6 × 10–6 cm/s.
High Performance Polymer/Ionic Liquid Thermoplastic Solid Electrolyte Prepared by Solvent Free Processing for Solid State Lithium Metal Batteries
Authors: González Francisco , Tiemblo Pilar , García Nuria , Garcia-Calvo Oihane , Fedeli Elisabetta , Kvasha Andriy , Urdampilleta Idoia
Published: August 2018

A polymer/ionic liquid thermoplastic solid electrolyte based on poly(ethylene oxide) (PEO), modified sepiolite (TPGS-S), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and 1-Butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) ionic liquid is prepared using solvent free extrusion method. Its physical-chemical, electrical, and electrochemical properties are comprehensively studied. The investigated solid electrolyte demonstrates high ionic conductivity together with excellent compatibility with lithium metal electrode. Finally, truly Li-LiFePO4 solid state coin cell with the developed thermoplastic solid electrolyte demonstrates promising electrochemical performance during cycling under 0.2 C/0.5 C protocol at 60 °C.