bluuebunny/crossref_metadata_2025 huggingface dataset:
Reinforced Droop for Active Current Sharing in Parallel NPC Inverter for Islanded AC Microgrid Application
Authors: Purushotham Monica , Muniswamy Kowsalya
Published: August 2019

The paper investigates the current sharing in parallel 3-level Neutral point clamped inverter for islanded AC microgrid application. In Distributed generation, parallel power electronic interface based microgrid suffers from power quality issues due to inaccurate output current sharing. To address the current sharing problem, the paper proposes an improved droop technique that reinforces the droop loop by infusing the incurred voltage drop accountable for inaccurate current sharing at the inverter output. The control based on droop reference is bounded with regard to output current since the output impedance influences the output current of the inverter largely. Besides that, the parallel NPC inverter also suffers from dc link voltage imbalance due to neutral currents. To address these issues a control strategy is proposed in the research work in which the processed DC offset is incorporated into the reinforced droop loop and the generated reference is utilized with feedback control to accurately share the currents under linear and nonlinear load conditions. The effectiveness of devised reinforced droop strategy is realized in MATLAB/Simulink environment and experimental validation is carried out with the field-programmable gate array as hardware interface to the hardware laboratory prototype of parallel NPC inverter.
Mitigating the Impacts of Covert Cyber Attacks in Smart Grids Via Reconstruction of Measurement Data Utilizing Deep Denoising Autoencoders
Authors: Ahmed Saeed , Lee YoungDoo , Hyun Seung-Ho , Koo Insoo
Published: August 2019

As one of the most diversified cyber-physical systems, the smart grid has become more decumbent to cyber vulnerabilities. An intelligently crafted, covert, data-integrity assault can insert biased values into the measurements collected by a sensor network, to elude the bad data detector in the state estimator, resulting in fallacious control decisions. Thus, such an attack can compromise the secure and reliable operations of smart grids, leading to power network disruptions, economic loss, or a combination of both. To this end, in this paper, we propose a novel idea for the reconstruction of sensor-collected measurement data from power networks, by removing the impacts of the covert data-integrity attack. The proposed reconstruction scheme is based on a latterly developed, unsupervised learning algorithm called a denoising autoencoder, which learns about the robust nonlinear representations from the data to root out the bias added into the sensor measurements by a smart attacker. For a robust, multivariate reconstruction of the attacked measurements from multiple sensors, the denoising autoencoder is used. The proposed scheme was evaluated utilizing standard IEEE 14-bus, 39-bus, 57-bus, and 118-bus systems. Simulation results confirm that the proposed scheme can handle labeled and non-labeled historical measurement data and results in a reasonably good reconstruction of the measurements affected by attacks.
Long-Term Demand Forecasting in a Scenario of Energy Transition
Authors: Sánchez-Durán Rafael , Luque Joaquín , Barbancho Julio
Published: August 2019

The energy transition from fossil fuels to carbon-free sources will be a big challenge in the coming decades. In this context, the long-term prediction of energy demand plays a key role in planning energy infrastructures and in adopting economic and energy policies. In this article, we aimed to forecast energy demand for Spain, mainly employing econometrics techniques. From information obtained from institutional databases, energy demand was decomposed into many factors and economy-related activity sectors, obtaining a set of disaggregated sequences of time-dependent values. Using time-series techniques, a long-term prediction was then obtained for each component. Finally, every element was aggregated to obtain the final long-term energy demand forecast. For the year 2030, an energy demand equivalent to 82 million tons of oil was forecast. Due to improvements in energy efficiency in the post-crisis period, a decoupling of economy and energy demand was obtained, with a 30% decrease in energy intensity for the period 2005–2030. World future scenarios show a significant increase in energy demand due to human development of less developed economies. For Spain, our research concluded that energy demand will remain stable in the next decade, despite the foreseen 2% annual growth of the nation’s economy. Despite the enormous energy concentration and density of fossil fuels, it will not be affordable to use them to supply energy demand in the future. The consolidation of renewable energies and increasing energy efficiency is the only way to satisfy the planet’s energy needs.
Virtual Assessment and Experimental Validation of Power Loss Contributions in Swash Plate Type Axial Piston Pumps
Authors: Hasko Daniel , Shang Lizhi , Noppe Eric , Lefrançois Emmanuel
Published: August 2019

The understanding of the power loss contributions of each loss source is essential for an effective development of swash plate type axial piston pump. However, it is difficult to obtain the assessment of the power loss distribution due to the lack of methodologies that allow an independent evaluation of each source. This paper addresses this challenge using the most recent simulation methods. It describes the determination of each source, along with the corresponding loss of performance, and the principle of their prediction during the design phase. It also reports the validation of the simulation model by comparing the simulated dynamic displacement chamber pressure and the solid body temperature distribution with measurements obtained from a special pump prototype. This proposed virtual assessment of power loss contributions is demonstrated on a commercial hydraulic unit and the detailed results are reported in this paper.
Effects of a Delayed Expansion of Interconnector Capacities in a High RES-E European Electricity System
Authors: Ritter David , Meyer Roland , Koch Matthias , Haller Markus , Bauknecht Dierk , Heinemann Christoph
Published: August 2019

In order to achieve a high renewable share in the electricity system, a significant expansion of cross-border exchange capacities is planned. Historically, the actual expansion of interconnector capacities has significantly lagged behind the planned expansion. This study examines the impact that such continued delays would have when compared to a strong interconnector expansion in an ambitious energy transition scenario. For this purpose, scenarios for the years 2030, 2040, and 2050 are examined using the electricity market model PowerFlex EU. The analysis reveals that both CO2 emissions and variable costs of electricity generation increase if interconnector expansion is delayed. This effect is most significant in the scenario year 2050, where lower connectivity leads roughly to a doubling of both CO2 emissions and variable costs of electricity generation. This increase results from a lower level of European electricity trading, a curtailment of electricity from a renewable energy source (RES-E), and a corresponding higher level of conventional electricity generation. Most notably, in Southern and Central Europe, less interconnection leads to higher use of natural gas power plants since less renewable electricity from Northern Europe can be integrated into the European grid.
On the Melting Process of the Phase Change Material in Horizontal Rectangular Enclosures
Authors: Duan Juan , Xiong Yongliang , Yang Dan
Published: August 2019

Phase change material (PCM) is one of the most important ways to store and manage energy. The melting process of PCM in a rectangular enclosure with the different aspect ratio is frequently related to some thermal energy storage devices. In this work, the melting of PCM in the horizontal rectangular enclosures heated from the different sides and the influence of aspect ratio of the rectangle are carefully studied. The enthalpy porosity technique and the finite volume method (FVM) are used to simulate the melting process numerically. The results show that the melting process of PCM can be dominated by conduction or natural convection due to the different heated sides. The melting of PCM in the enclosure heated from the bottom side is firstly affected by conduction and then mostly influenced by convection. In addition, the aspect ratio of the rectangular enclosure is found to play an important role in the melting process. Finally, a series of fitting correlations of the liquid fraction, Nusselt number and the energy storage are presented with the influence of aspect ratios in order to provide the reference for designing the rectangular container of PCM. This study is helpful for the selection of an appropriate aspect ratio and heating method to achieve the desired energy storage performance of encapsulated PCM.
The Hot QTL Locations for Potassium, Calcium, and Magnesium Nutrition and Agronomic Traits at Seedling and Maturity Stages of Wheat under Different Potassium Treatments
Authors: Shen Xing , Yuan Yapei , Zhang Han , Guo Ying , Zhao Yan , Li Sishen , Kong Fanmei
Published: August 2019

Potassium (K) is one of the most important mineral nutrients for wheat. In this study, the effects of low K (LK) treatments and the quantitative trait loci (QTLs) for K, calcium (Ca), and magnesium (Mg) use efficiency traits, both at the seedling and maturity stages of wheat, were investigated. The set of “Tainong 18 × Linmai 6” recombinant inbred lines (RILs) were used to identify the QTLs under different K treatments using hydroponic culture and field trials. The majority of K concentrations and content-related traits at seedling and maturity stages decreased with reduced K supply, but the K use efficiency-related traits increased. In contrast, with reduced K supply, the contents of Ca and Mg increased, while the Ca and Mg use efficiency decreased. A total of 217 QTLs for seedling traits and 89 QTLs for adult traits were detected. Four relatively high-frequency QTLs (RHF-QTLs) and 18 QTL clusters (colocation of QTLs for more than two traits) were detected. Eight clusters were detected for K-, Ca-, and Mg-related traits simultaneously. This means that these traits might be controlled by the same QTL. In addition, we highlight that 4B might be an important chromosome regulating the nutrition of K, Ca, and Mg in wheat. The 4B chromosome and four hot QTL clusters, which located 45 QTLs, might be important potential targets for further investigation.
Nation, Ethnicity, Milieus, and Multiple “We’s”. The Case of Kenya
Authors: Neubert Dieter
Published: August 2019

The title of the volume “Future Africa—beyond the nation?” has several implications. Nation is presented as an entity relevant to identification and identity; and in the combination with “future”, nation implies a political vision. It is not hard to find good examples in respect of these implications. However, there are other entities important for to political identification. Often, they do not go beyond the nation but refer to smaller collective identities, such as ethnicity. The revived debate on “the middle class” implies that particular social groupings, such as class, may play a role, too. The question is how relevant are the nation and other collective political identities in Africa, and are they exclusive? Looking at the case of Kenya, we see on the one hand that collective (political) identities, such as ethnicity, are mobilized especially during elections. On the other hand, these collective identities are less dominant in everyday life and give way to different conducts of life (conceptualized as “milieus”) that are less politicized. We see people maneuvering between multiple “we’s”. Strong political identities are mobilized only in particular conflict-loaded situations that restructure identities in simple binary oppositions of “we” and “they”.
Epidemiology of Mortality Due to Prostate Cancer in Poland, 2000–2015
Authors: Pikala Małgorzata , Burzyńska Monika , Maniecka-Bryła Irena
Published: August 2019

The aim of the study was to assess trends in mortality and years of life lost due to prostate cancer (PCa) in Poland in 2000–2015. The crude death rates (CDR), standardised death rates (SDR), standard expected years of life lost per living person (SEYLLp) and per death (SEYLLd) values were calculated. Joinpoint models were used to analyse time trends. In the study period, 61,928 men died of PCa. The values of mortality rates in 2000 (per 100,000) were: CDR = 16.97, SDR = 16.17, SEYLLp = 332.1. In 2015, the values of all rates increased: CDR = 26.22, SDR = 16.69, SEYLLp = 429.5. However, the SEYLLd value decreased from 15.62 to one man who died due to PCa in 2000 to 13.78 in 2015. The highest SEYLLp values occurred in the group of men with primary education (619.5 in 2000 and 700.7 in 2015). They were respectively 2.24 and 2.96 times higher than in men with higher education (275.7 and 237.1). SEYLLp values increased in urban areas (from 295.7 to 449.4), slightly changed in the rural areas (from 391.5 to 400.2). Unfavorable trends in mortality due to PCa in Poland require explanation of the causes and implementation of appropriate actions aimed at mortality reducing.
Income, Self-Rated Health, and Morbidity. A Systematic Review of Longitudinal Studies
Authors: Reche Elena , König Hans-Helmut , Hajek André
Published: August 2019

If people were asked whether income changes influence self-rated health and morbidity, they would probably answer yes. Indeed, previous studies validated this assumption, but most of them used cross-sectional data and only considered self-rated health as the decisive factor. On the other hand, there are a few studies using longitudinal data, which found a much smaller association between income and self-rated health. In order to give a conclusive overview of the current study situation, this review summarizes and examines studies which use only longitudinal data. In addition to self-rated health, the effects of income on the objective factor of morbidity were also investigated. The review includes a total of 14 papers that use data from seven different countries. It concludes that there is a small, statistically significant, positive impact of increased income on self-rated health, but a negative association between income growth and morbidity. Taking the limitations of confounders, attrition, and selection bias into account, the results may even be insignificant.
Reply to Mekary, R.A.; Ding, E.L. Isotemporal Substitution as the Gold Standard Model for Physical Activity Epidemiology: Why It Is the Most Appropriate for Activity Time Research. Int. J. Environ. Res. Public Health 2019, 16, 797
Authors: Biddle Gregory J. H. , Edwardson Charlotte L. , Henson Joseph , Rowlands Alex V. , Yates Thomas
Published: August 2019

Firstly, we would like to thank the authors for taking the time to review and comment on our paper [...]
Estimating the Double Burden of Malnutrition among 595,975 Children in 65 Low- and Middle-Income Countries: A Meta-Analysis of Demographic and Health Surveys
Authors: Akombi Blessing J. , Chitekwe Stanley , Sahle Berhe W. , Renzaho Andre M.N.
Published: August 2019

Introduction: Given the changing global nutrition landscape, the double burden of malnutrition is a major public health challenge in many developing countries. The main aim of this study is to estimate the double burden of malnutrition among children in low- and middle-income countries (LMICs). Methods: This study used cross-sectional data from Demographic and Health Surveys (2001–2016). A meta-analysis was conducted to estimate the prevalence of malnutrition indicators in 595,975 children under five years from 65 LMICs. Significant heterogeneity was detected among the various surveys (I2 >50%), hence a random-effect model was used. Sensitivity analysis was also performed, to examine the effects of outliers. Results: The pooled estimate for stunting, wasting, underweight, and overweight/obesity was 29.0%, 7.5%, 15.5%, and 5.3% respectively. Countries with the highest coexistence of undernutrition and overweight/obesity were: South Africa (stunting 27.4% (95% CI: 25.1, 29.8); overweight/obesity 13.3% (95% CI: 11.5, 15.2)), Sao Tome and Principe (stunting 29.0% (95% CI: 26.8, 31.4); overweight/obesity 10.5% (95% CI: 9.0, 12.1)), Swaziland (stunting 28.9% (95% CI: 27.3, 30.6); overweight/obesity 10.8% (95% CI: 9.7, 12.0)), Comoros (stunting 30.0% (95% CI: 28.3, 31.8); overweight/obesity 9.3% (95% CI: 8.3, 10.5)), and Equatorial Guinea (stunting 25.9% (95% CI: 23.4, 28.7); overweight/obesity 9.7% (95% CI: 8.0, 11.6)). Conclusions: There is an urgent need to strengthen existing policies on child malnutrition to integrate and scale up opportunities for innovative approaches which address the double burden of malnutrition in children under five years in LMICs.
An Occupational Heat–Health Warning System for Europe: The HEAT-SHIELD Platform
Authors: Morabito Marco , Messeri Alessandro , Noti Pascal , Casanueva Ana , Crisci Alfonso , Kotlarski Sven , Orlandini Simone , Schwierz Cornelia , Spirig Christoph , Kingma Boris R.M. , Flouris Andreas D. , Nybo Lars
Published: August 2019

Existing heat–health warning systems focus on warning vulnerable groups in order to reduce mortality. However, human health and performance are affected at much lower environmental heat strain levels than those directly associated with higher mortality. Moreover, workers are at elevated health risks when exposed to prolonged heat. This study describes the multilingual “HEAT-SHIELD occupational warning system” platform (https://heatshield.zonalab.it/) operating for Europe and developed within the framework of the HEAT-SHIELD project. This system is based on probabilistic medium-range forecasts calibrated on approximately 1800 meteorological stations in Europe and provides the ensemble forecast of the daily maximum heat stress. The platform provides a non-customized output represented by a map showing the weekly maximum probability of exceeding a specific heat stress condition, for each of the four upcoming weeks. Customized output allows the forecast of the personalized local heat-stress-risk based on workers’ physical, clothing and behavioral characteristics and the work environment (outdoors in the sun or shade), also taking into account heat acclimatization. Personal daily heat stress risk levels and behavioral suggestions (hydration and work breaks recommended) to be taken into consideration in the short term (5 days) are provided together with long-term heat risk forecasts (up to 46 days), all which are useful for planning work activities. The HEAT-SHIELD platform provides adaptation strategies for “managing” the impact of global warming.
Melatonin Improves the Fertilization Capacity of Sex-Sorted Bull Sperm by Inhibiting Apoptosis and Increasing Fertilization Capacitation via MT1
Authors: Li Chong-Yang , Hao Hai-Sheng , Zhao Ya-Han , Zhang Pei-Pei , Wang Hao-Yu , Pang Yun-Wei , Du Wei-Hua , Zhao Shan-Jiang , Liu Yan , Huang Jin-Ming , Wang Jing-Jing , Ruan Wei-Min , Hao Tong , Reiter Russel J. , Zhu Hua-Bin , Zhao Xue-Ming
Published: August 2019

Little information is available regarding the effect of melatonin on the quality and fertilization capability of sex-sorted bull sperm, and even less about the associated mechanism. Sex-sorted sperm from three individual bulls were washed twice in wash medium and incubated in a fertilization medium for 1.5 h, and each was supplemented with melatonin (0, 10−3 M, 10−5 M, 10−7 M, and 10−9 M). The reactive oxygen species (ROS) and endogenous antioxidant activity (glutathione peroxidase (GPx); superoxide dismutase (SOD); catalase (CAT)), apoptosis (phosphatidylserine [PS] externalization; mitochondrial membrane potential (Δψm)), acrosomal integrity events (malondialdehyde (MDA) level; acrosomal integrity), capacitation (calcium ion [Ca2+]i level; cyclic adenosine monophosphate (cAMP); capacitation level), and fertilization ability of the sperm were assessed. Melatonin receptor 1 (MT1) and 2 (MT2) expression were examined to investigate the involvement of melatonin receptors on sex-sorted bull sperm capacitation. Our results show that treatment with 10−5 M melatonin significantly decreased the ROS level and increased the GPx, SOD, and CAT activities of sex-sorted bull sperm, which inhibited PS externalization and MDA levels, and improved Δψm, acrosomal integrity, and fertilization ability. Further experiments showed that melatonin regulates sperm capacitation via MT1. These findings contribute to improving the fertilization capacity of sex-sorted bull sperm and exploring the associated mechanism.
Genetic Landscape of Rett Syndrome Spectrum: Improvements and Challenges
Authors: Vidal Silvia , Xiol Clara , Pascual-Alonso Ainhoa , O’Callaghan M. , Pineda Mercè , Armstrong Judith
Published: August 2019

Rett syndrome (RTT) is an early-onset neurodevelopmental disorder that primarily affects females, resulting in severe cognitive and physical disabilities, and is one of the most prevalent causes of intellectual disability in females. More than fifty years after the first publication on Rett syndrome, and almost two decades since the first report linking RTT to the MECP2 gene, the research community’s effort is focused on obtaining a better understanding of the genetics and the complex biology of RTT and Rett-like phenotypes without MECP2 mutations. Herein, we review the current molecular genetic studies, which investigate the genetic causes of RTT or Rett-like phenotypes which overlap with other genetic disorders and document the swift evolution of the techniques and methodologies employed. This review also underlines the clinical and genetic heterogeneity of the Rett syndrome spectrum and provides an overview of the RTT-related genes described to date, many of which are involved in epigenetic gene regulation, neurotransmitter action or RNA transcription/translation. Finally, it discusses the importance of including both phenotypic and genetic diagnosis to provide proper genetic counselling from a patient’s perspective and the appropriate treatment.
Zr-89 Immuno-PET Targeting Ectopic ATP Synthase Enables In-Vivo Imaging of Tumor Angiogenesis
Authors: Park Bok-Nam , Kim Ga-Hee , Ko Seung-A , Shin Ga-Hee , Lee Su-Jin , An Young-Sil , Yoon Joon-Kee
Published: August 2019

In this study, we synthesized a Zr-89-labeled anti-adenosine triphosphate synthase monoclonal antibody (ATPS mAb) for applications in immuno-positron emission tomography (PET) and evaluated its feasibility for angiogenesis imaging. The cellular uptake of Zr-89 ATPS mAb was measured after treatment of cancer cell lines in vitro, and its biodistribution was evaluated at 4, 24 and 48 h in vivo in mice bearing xenografts. PET images were acquired at 4, 24, 48, and 96 h after Zr-89 ATPS mAb administration. Tumor angiogenesis was analyzed using anti-CD31 immunofluorescence staining. The cellular uptake of Zr-89 ATPS mAb increased over time in MDA-MB-231 breast cancer cells but did not increase in PC3 prostate cancer cells. The tumor uptake of Zr-89 ATPS mAb at 24 h was 9.4 ± 0.9% ID/g for MDA-Mb-231 cells and was 3.8 ± 0.6% ID/g for PC3 cells (p = 0.004). Zr-89 ATPS mAb uptake in MDA-MB-231 xenografts was inhibited by the administration of cold ATPS mAb (4.4 ± 0.5% ID/g, p = 0.011). Zr-89 ATPS mAb uptake could be visualized by PET for up to 96 h in MDA-MB-231 tumors. In contrast, there was no distinct tumor uptake detected by PET in the PC3 xenograft model. CD31-positive tumor vessels were abundant in MDA-MB-231 tumors, whereas they were scarcely detected in PC3 tumors. In conclusion, ATPS mAb was successfully labeled with Zr-89, which could be used for immuno-PET imaging targeting tumor angiogenesis.
Depicting the Core Transcriptome Modulating Multiple Abiotic Stresses Responses in Sesame (Sesamum indicum L.)
Authors: Dossa Komivi , Mmadi Marie A. , Zhou Rong , Zhang Tianyuan , Su Ruqi , Zhang Yujuan , Wang Linhai , You Jun , Zhang Xiurong
Published: August 2019

Sesame is a source of a healthy vegetable oil, attracting a growing interest worldwide. Abiotic stresses have devastating effects on sesame yield; hence, studies have been performed to understand sesame molecular responses to abiotic stresses, but the core abiotic stress-responsive genes (CARG) that the plant reuses in response to an array of environmental stresses are unknown. We performed a meta-analysis of 72 RNA-Seq datasets from drought, waterlogging, salt and osmotic stresses and identified 543 genes constantly and differentially expressed in response to all stresses, representing the sesame CARG. Weighted gene co-expression network analysis of the CARG revealed three functional modules controlled by key transcription factors. Except for salt stress, the modules were positively correlated with the abiotic stresses. Network topology of the modules showed several hub genes predicted to play prominent functions. As proof of concept, we generated over-expressing Arabidopsis lines with hub and non-hub genes. Transgenic plants performed better under drought, waterlogging, and osmotic stresses than the wild-type plants but did not tolerate the salt treatment. As expected, the hub gene was significantly more potent than the non-hub gene. Overall, we discovered several novel candidate genes, which will fuel investigations on plant responses to multiple abiotic stresses.
Interleukin 4 Moderately Affects Competence of Pluripotent Stem Cells for Myogenic Conversion
Authors: Świerczek-Lasek Barbara , Neska Jacek , Kominek Agata , Tolak Łukasz , Czajkowski Tomasz , Jańczyk-Ilach Katarzyna , Stremińska Władysława , Piwocka Katarzyna , Ciemerych Maria A. , Archacka Karolina
Published: August 2019

Pluripotent stem cells convert into skeletal muscle tissue during teratoma formation or chimeric animal development. Thus, they are characterized by naive myogenic potential. Numerous attempts have been made to develop protocols enabling efficient and safe conversion of pluripotent stem cells into functional myogenic cells in vitro. Despite significant progress in the field, generation of myogenic cells from pluripotent stem cells is still challenging—i.e., currently available methods require genetic modifications, animal-derived reagents, or are long lasting—and, therefore, should be further improved. In the current study, we investigated the influence of interleukin 4, a factor regulating inter alia migration and fusion of myogenic cells and necessary for proper skeletal muscle development and maintenance, on pluripotent stem cells. We assessed the impact of interleukin 4 on proliferation, selected gene expression, and ability to fuse in case of both undifferentiated and differentiating mouse embryonic stem cells. Our results revealed that interleukin 4 slightly improves fusion of pluripotent stem cells with myoblasts leading to the formation of hybrid myotubes. Moreover, it increases the level of early myogenic genes such as Mesogenin1, Pax3, and Pax7 in differentiating embryonic stem cells. Thus, interleukin 4 moderately enhances competence of mouse pluripotent stem cells for myogenic conversion.
Contemporary Review of Borderline Resectable Pancreatic Ductal Adenocarcinoma
Authors: Bonds Morgan , Rocha Flavio G.
Published: August 2019

Borderline resectable pancreatic adenocarcinoma (PDAC) presents challenges in definition and treatment. Many different definitions exist for this disease. Some are based on anatomy alone, while others include factors such as disease biology and patient performance status. Regardless of definition, evidence suggests that borderline resectable PDAC is a systemic disease at the time of diagnosis. There is high-level evidence to support the use of neoadjuvant systemic therapy in these cases. Evidence to support the use of radiation therapy is ongoing. There are ongoing trials investigating the available neoadjuvant therapies for borderline resectable PDAC that may provide clarity in the future.
Decision Tree Methods for Predicting Surface Roughness in Fused Deposition Modeling Parts
Authors: Barrios Juan M. , Romero Pablo E.
Published: August 2019

3D printing using fused deposition modeling (FDM) includes a multitude of control parameters. It is difficult to predict a priori what surface finish will be achieved when certain values are set for these parameters. The objective of this work is to compare the models generated by decision tree algorithms (C4.5, random forest, and random tree) and to analyze which makes the best prediction of the surface roughness in polyethylene terephthalate glycol (PETG) parts printed in 3D using the FDM technique. The models have been created using a dataset of 27 instances with the following attributes: layer height, extrusion temperature, print speed, print acceleration, and flow rate. In addition, a dataset has been created to evaluate the models, consisting of 15 additional instances. The models generated by the random tree algorithm achieve the best results for predicting the surface roughness in FDM parts.
Hydrogen-Assisted Crack Growth in the Heat-Affected Zone of X80 Steels during in Situ Hydrogen Charging
Authors: Qu Jinglong , Feng Min , An Teng , Bi Zhongnan , Du Jinhui , Yang Feng , Zheng Shuqi
Published: August 2019

Herein, the hydrogen embrittlement of a heat-affected zone (HAZ) was examined using slow strain rate tension in situ hydrogen charging. The influence of hydrogen on the crack path of the HAZ sample surfaces was determined using electron back scatter diffraction analysis. The hydrogen embrittlement susceptibility of the base metal and the HAZ samples increased with increasing current density. The HAZ samples have lower resistance to hydrogen embrittlement than the base metal samples in the same current density. Brittle circumferential cracks located at the HAZ sample surfaces were perpendicular to the loading direction, and the crack propagation path indicated that five or more cracks may join together to form a longer crack. The fracture morphologies were found to be a mixture of intergranular and transgranular fractures. Hydrogen blisters were observed on the HAZ sample surfaces after conducting tensile tests at a current density of 40 mA/cm2, leading to a fracture in the elastic deformation stage.
A Simulation Study to Calculate a Structure Conceived by Eugène Viollet-le-Duc in 1850 with Finite Element Analysis
Authors: Rueda Márquez de la Plata Adela , Cruz Franco Pablo Alejandro
Published: August 2019

This study aims to investigate the application of finite element calculations to mixed structures of complex materials. As an example, we chose a vault designed by Eugène Viollet-le-Duc in 1850, at which time it was not possible to verify the complexities of the different materials working together in a single structure using these calculation methods. To carry out the simulation, the internal qualities of each material and its current equivalent are taken into account. Thus, the composition of each element is crucial for its integration into the whole structure and its modeling and subsequent calculation. With this research, we show that a finite element analysis can also be applied to structures that are yet to be built. Furthermore, we verify the technological, construction and materials knowledge that has led us here and demonstrate that what was once a utopian vision can now be realized using the structures and materials we have access to today.
Structural and Thermal Properties of Montmorillonite/Ionic Liquid Composites
Authors: Alekseeva Olga , Noskov Andrew , Grishina Elena , Ramenskaya Lyudmila , Kudryakova Nadezhda , Ivanov Vladimir , Agafonov Alexander
Published: August 2019

Composites of montmorillonite K10 (MMT K10) and ionic liquid (IL) containing a 1-butyl-3-methyl-imidazolium cation ([BMIm]+) and various anions, such as bis (trifluoromethylsulfonyl) imide ([NTf2]−), trifluoromethanesulfonate ([OTf]−), and dicyanamide ([DCA]−) have been obtained in this work. A number of methods, such as dynamic light scattering (DLS), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetry (TG), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and nitrogen adsorption–desorption have been used to characterize clay, and to study the structure and thermal behaviour of the composites. It has been found that the MMT K10 powder has a narrow particle size distribution with a peak at 246 nm and a mesoporous structure (SBET=195 m2/g). According to the FTIR spectra, MMT K10/IL interaction depends on the IL type. It has been identified that confined ionic liquid interacts with both clay and adsorbed water in accordance with the hydrophilicity and size of the anion, in the following order: [DCA]− > [OTf]− > [NTf2]−. Characteristic temperatures of glass transition, crystallization, and melting have been determined for the ionic liquids under study and their MMT K10 composites. It has been revealed that when IL is adsorbed on the surface of clay, the phase transitions in IL change. The greatest changes are observed in the case of BMImNTf2. By applying the method of thermogravimetric analysis, it is shown that composite formation is accompanied by a decrease in the IL thermal stability. Apparently, the highly developed surface of montmorillonite K10, obtained by acid treatment, plays a major role in the decrease in the IL’s thermal stability. The influence of the IL anion on the thermal and spectral characteristics of an MMT K10/IL composite was studied for the first time.
Densification, Microstructure and Properties of 90W-7Ni-3Fe Fabricated by Selective Laser Melting
Authors: Li Junfeng , Wei Zhengying , Zhou Bokang , Wu Yunxiao , Chen Sheng-Gui , Sun Zhenzhong
Published: August 2019

The preparation of refractory tungsten and tungsten alloys has always been challenging due to their inherent properties. Selective laser melting (SLM) offers a choice for preparing tungsten and tungsten alloys. In this work, 90W-7Ni-3Fe samples were prepared by selective laser melting and investigated. Different process parameter combinations were designed according to the Taguchi method, and volumetric energy density (VED) was defined. Subsequently, the effects of process parameters on densification, phase composition, microstructure, tensile properties, and microhardness were investigated. Nearly a full densification sample (≥99%) was obtained under optimized process parameters, and the value of VED was no less than 300 J/mm3. Laser power had a dominant influence on densification behavior compared with other parameters. The main phases of 90W-7Ni-3Fe are W and γ-(Ni-Fe), dissolved with partial W. In addition, 90W-7Ni-3Fe showed a high tensile strength (UTS = 1121 MPa) with poor elongation (<1%). A high average microhardness (>400 HV0.3) was obtained, but the microhardness presented a fluctuation along building direction due to the inhomogeneous microstructure.
ANOVA Design for the Optimization of TiO2 Coating on Polyether Sulfone Membranes
Authors: Orooji Yasin , Ghasali Ehsan , Emami Nahid , Noorisafa Fatemeh , Razmjou Amir
Published: August 2019

There have been developments in the optimization of polyethersulfone (PES) membranes, to provide antifouling and mechanically stable surfaces which are vital to water purification applications. There is a variety of approaches to prepare nanocomposite PES membranes. However, an optimized condition for making such membranes is in high demand. Using experimental design and statistical analysis (one-half fractional factorial design), this study investigates the effect of different parameters featured in the fabrication of membranes, as well as on the performance of a nanocomposite PES/TiO2 membrane. The optimized parameters obtained in this study are: exposure time of 60 s, immersion time above 10 h, glycerol time of 4 h, and a nonsolvent volumetric ratio (isopropanol/water) of 30/70 for PES and dimethylacetamide (PES-DMAc) membrane and 70/30 for PES and N-methyl-2-pyrrolidone (PES-NMP) membrane. A comparison of the contributory factors for different templating agents along with a nanocomposite membrane control revealed that F127 triblock copolymer resulted in an excellent antifouling membrane with a higher bovine serum albumin rejection and flux recovery of 83.33%.
Photo-Fenton Degradation of Pentachlorophenol: Competition between Additives and Photolysis
Authors: Vergura Erika Pia , Garcia-Ballestreros Sara , Vercher Rosa Francisca , Santos-Juanes Lucas , Bianco Prevot Alessandra , Arques Antonio
Published: August 2019

In the present work, the photo-Fenton degradation of pentachlorophenol (PCP, 1 mg/L) has been studied under simulated and natural solar irradiation; moreover, the effect on the process efficiency of urban waste-derived soluble bio-based substances (SBO), structurally comparable to humic acids, has been investigated. Experiments showed a crucial role of PCP photolysis, present in the solar pilot plant and hindered by the Pyrex® filter present in the solar simulator. Indeed, the SBO screen negatively affects PCP degradation when working under natural solar light, where the photolysis of PCP is relevant. In contrast, in the absence of PCP photolysis, a significant improvement of the photo-Fenton process was observed when added to SBO. Furthermore, SBO were able to extend the application of the photo-Fenton process at circumneutral pH values, due to their ability to complex iron, avoiding its precipitation as oxides or hydroxides. This positive effect has been observed at higher concentration of Fe(II) (4 mg/L), whereas at 1 mg/L, the degradation rates of PCP were comparable in the presence and absence of SBO.
Hydroxyurea-Loaded Albumin Nanoparticles: Preparation, Characterization, and In Vitro Studies
Authors: Tazhbayev Yerkeblan , Mukashev Olzhas , Burkeev Meiram , Kreuter Jörg
Published: August 2019

Human serum albumin nanoparticles (HSA-NPs) have been widely used as drug delivery systems. In most cases, HSA-NPs are formed by the method of desolvation in the presence of glutaraldehyde as a crosslinking agent. In the present study, we showed the possibility of crosslinking human serum albumin (HSA) molecules with natural agents, urea, and cysteine at the nanoparticle level under mild conditions (at room temperature of 20–25 °C). Optimal concentrations of the interacting components (HSA, urea, and cysteine) were found to produce nanoparticles with optimal physico-chemical parameters (particle size, polydispersity, zeta potential, yield, etc.) for application as drug carriers. We used hydroxyurea (HU), a simple organic compound currently used as a cancer chemotherapeutic agent. The results indicated sizes of 196 ± 5 nm and 288 ± 10 nm with a surface charge of −22 ± 3.4 mV and −17.4 ± 0.5 mV for HSA-NPs (20 mg/mL of HSA, 0.01 mg/mL of cysteine, and 10 mg/mL of urea) and HSA–HU-NPs (2 mg/mL of HU), respectively. The yield of the HSA–HU-NPs was ~93% with an encapsulation efficiency of ~77%. Thus, the particles created (immobilized with HU) were stable over time and able to prolong the effect of the drug.
Object-Based Flood Analysis Using a Graph-Based Representation
Authors: Debusscher Bos , Van Coillie Frieke
Published: August 2019

The amount of freely available satellite data is growing rapidly as a result of Earth observation programmes, such as Copernicus, an initiative of the European Space Agency. Analysing these huge amounts of geospatial data and extracting useful information is an ongoing pursuit. This paper presents an alternative method for flood detection based on the description of spatio-temporal dynamics in satellite image time series (SITS). Since synthetic aperture radar (SAR) satellite data has the capability of capturing images day and night, irrespective of weather conditions, it is the preferred tool for flood mapping from space. An object-based approach can limit the necessary computer power and computation time, while a graph-based approach allows for a comprehensible interpretation of dynamics. This method proves to be a useful tool to gain insight in a flood event. Graph representation helps to identify and locate entities within the study site and describe their evolution throughout the time series.
Development and Optimization of an Automated Fixed-Location Time Lapse Photogrammetric Rock Slope Monitoring System
Authors: Kromer Ryan , Walton Gabe , Gray Brian , Lato Matt , Group Robert
Published: August 2019

An automated, fixed-location, time lapse camera system was developed as an alternative to monitoring geological processes with lidar or ground-based interferometric synthetic-aperture radar (GB-InSAR). The camera system was designed to detect fragmental rockfalls and pre-failure deformation at rock slopes. It was implemented at a site along interstate I70 near Idaho Springs, Colorado. The camera system consists of five digital single-lens reflex (DSLR) cameras which collect photographs of the rock slope daily and automatically upload them to a server for processing. Structure from motion (SfM) photogrammetry workflows were optimized to be used without ground control. An automated change detection pipeline registers the point clouds with scale adjustment and filters vegetation. The results show that if a fixed pre-calibration of internal camera parameters is used, an accuracy close to that obtained using ground control points can be achieved. Over the study period between March 19, 2018 and June 24, 2019, a level of detection between 0.02 to 0.03 m was consistently achieved, and over 50 rockfalls between 0.003 to 0.1 m3 were detected at the study site. The design of the system is fit for purpose in terms of its ground resolution size and accuracy and can be adapted to monitor a wide range of geological and geomorphic processes at a variety of time scales.
Defect Detection of Aluminium Plates Based on Near-Field Enhancement of Lamb Waves Generated Using an Electromagnetic Acoustic Tranducer
Authors: Zhou Peng , Zhang Chu , Xu Ke , Ren Weiping
Published: August 2019

Ultrasonic testing is an important means to detect defacing defects, such as scratches and cracks, but when the size of these defects is smaller than the wavelength of ultrasonic waves, it is difficult to detect them using traditional methods like the pulse-echo method and broadband ultrasound attenuation method for the diffraction of ultrasonic waves at the defects. Based on the non-contact characteristic of electromagnetic acoustic transducers (EMATs), a transducer for scanning inspection was developed in this paper. The transducer was utilized to detect and measure the depth of the defacing defects on an aluminium plate based on the near-field enhancement of ultrasonic Lamb waves. The results show that the amplitude of the S0 Lamb wave experiences a large enhancement when the transducer is passed over the scratch defects and the enhancement has a clearly positive correlation with the depth of the scratch defects. When the depth increases from 0.1 mm to 0.9 mm, the amplitude of S0 Lamb waves increases from 1.13 times to 2.27 times the S0 Lamb waves received on the aluminium plate without defects. The new method can be utilized to detect the defacing defects on the aluminium plate and get better detection effects than the traditional methods without analyzing the relatively small reflection waves.
Methodical Approach for Determining the Length of Drill Channels in Osteosynthesis
Authors: Sorg Michael , Osmers Jan , Fischer Andreas
Published: August 2019

In order to fix a fracture in osteosynthesis, it is necessary to attach screws bicortically to the bone. The length of the screws must be selected correctly in 1-mm increments: otherwise, injury to the surrounding tissue structure or insufficient fixation will result. The drill channel length can only be determined preoperatively to a limited extent and with insufficient accuracy and is therefore determined intraoperatively with a mechanical caliper gauge. This length determination is error-prone, which often leads to a false screw selection and at the same time to considerable complications in the healing process. A novel approach based on a sensory drive train was pursued, with which all mechanical drilling parameters were recorded and evaluated in combination with a length measurement that allows for determining the drill channel length. In order to overcome the limitations of previous drill concepts, a precise length measurement of the drill channel was introduced. The amplitude of a stimulated linear oscillation of the drill was monitored for drilling channel length measurements in order to reliably detect the beginning of the drilling process. The method provides the information required for handheld drilling without the limitation of constant drilling parameters. With initial results from laboratory tests with pig bones, the measurement method for the drill channel length has been validated on a test bench of the drilling machine. With the laboratory tests, a measurement uncertainty of 0.3 mm was achieved, so screws with a 1-mm step width can be reliably selected.
The Changing Nature of Death Penalty in Vietnam: A Historical and Legal Inquiry
Authors: Tran Kien , Vu Cong Giao
Published: August 2019

This research centers on the change in the nature of the death penalty as expressed in law and practice throughout Vietnam’s history with a focus on modern time. Using a set of typical legal research methods, in particular, legal history, doctrinal research, philosophy of law and, sociology of law, the article analyzes the change and reform of capital offences in Vietnamese laws. It is revealed through our research that the nature of the death penalty has been fundamentally changed from an instrument of power and coercion during much of the history of the country to a manifestation of justice based on the ideas of rule of law and human rights that started to emerge in the early twentieth century, especially from 1986 onwards. As a result, the number of capital offences has been gradually reduced in three modern Criminal Codes. However, it is also noted that the number of capital sentences and executions appears to remain unchanged, even slightly increased. This creates a paradox that opens and invites a future, interdisciplinary research to thoroughly investigate the problem in the country. The article also argues that as the death penalty finds its moral and legal justifications along with the rise of the number of death sentences given to many serious criminal cases, the death penalty appears to find support among the public. In addition, the political sensitivity of the issue, as expressed through the prohibition on the disclosure of the death penalty data, will inhibit discourse on the problem. Together, they will maintain the existence and application of the death penalty in Vietnam in the time to come.
Exploring the Relationship between Urban Vitality and Street Centrality Based on Social Network Review Data in Wuhan, China
Authors: Yue Han , Zhu Xinyan
Published: August 2019

This study investigates the association between urban vitality and street centrality in Wuhan, China. Urban vitality was measured with social network review data. Street centrality was evaluated in terms of closeness, straightness, and betweenness in walking and driving mode. We constructed a square mesh to convert datasets of street centrality (segments) and urban vitality (points) into one unit for analysis. Geospatial visualization, a chi-square test, and correlation analysis were first employed to obtain an initial understanding of the spatial coupling relationship between urban vitality and street centrality. Then spatial regression models were applied to evaluate the significances and directions of the influences of street centrality on urban vitality. A geographical detector technique was utilized to further evaluate the magnitudes of these influences. The results suggest that street centrality plays an important role in shaping the spatial organization of urban vitality, and various street centralities presented marked differences in their association with urban vitality. More specifically, when considering street centrality in walking mode, betweenness affected urban vitality the most, followed by closeness and straightness. When considering street centrality in driving mode, straightness had the greatest influence on urban vitality, followed by closeness and betweenness.