bluuebunny/crossref_metadata_2025 huggingface dataset:
Antioxidant Therapies in Traumatic Brain Injury
Authors: Di Pietro Valentina , Yakoub Kamal M. , Caruso Giuseppe , Lazzarino Giacomo , Signoretti Stefano , Barbey Aron K. , Tavazzi Barbara , Lazzarino Giuseppe , Belli Antonio , Amorini Angela Maria
Published: March 2020

Due to a multiplicity of causes provoking traumatic brain injury (TBI), TBI is a highly heterogeneous pathology, characterized by high mortality and disability rates. TBI is an acute neurodegenerative event, potentially and unpredictably evolving into sub-chronic and chronic neurodegenerative events, with transient or permanent neurologic, cognitive, and motor deficits, for which no valid standardized therapies are available. A vast body of literature demonstrates that TBI-induced oxidative/nitrosative stress is involved in the development of both acute and chronic neurodegenerative disorders. Cellular defenses against this phenomenon are largely dependent on low molecular weight antioxidants, most of which are consumed with diet or as nutraceutical supplements. A large number of studies have evaluated the efficacy of antioxidant administration to decrease TBI-associated damage in various animal TBI models and in a limited number of clinical trials. Points of weakness of preclinical studies are represented by the large variability in the TBI model adopted, in the antioxidant tested, in the timing, dosages, and routes of administration used, and in the variety of molecular and/or neurocognitive parameters evaluated. The analysis of the very few clinical studies does not allow strong conclusions to be drawn on the real effectiveness of antioxidant administration to TBI patients. Standardizing TBI models and different experimental conditions, as well as testing the efficacy of administration of a cocktail of antioxidants rather than only one, should be mandatory. According to some promising clinical results, it appears that sports-related concussion is probably the best type of TBI to test the benefits of antioxidant administration.
Improvement of Marine Clay Soil Using Lime and Alkaline Activation Stabilized with Inclusion of Treated Coir Fibre
Authors: Kamaruddin Fatin Amirah , Nahazanan Haslinda , Kim Huat Bujang , Anggraini Vivi
Published: March 2020

Waste products have recently been used as one of the techniques in soil stabilization. The material is not just environmentally friendly, but also cheap. In this study, two different types of soil stabilizer—lime and alkaline activator (AA) with the inclusion of treated coir fibre as soil reinforcement in marine clay soil—were examined. The inclusion of fibre in the treated soil has had a positive impact in increasing the strength of the soil. Therefore, to assess the effectiveness of the soil treatment, mechanical tests such as indirect tensile strength, flexural test and unconfined compressive strength test were performed at three different curing periods (7, 28 and 90 days) on both untreated and treated soil. From the results, the inclusion of fibre in both lime and alkaline activation indicates an enhancement on post-peak behaviour from brittle to more ductile. Microstructural analyses of Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray (EDX) were also conducted after shearing to evaluate the changes of the soil before and after the treatment. Overall, results indicate that the treatment transformed the structure of the soil to become denser where it filled the large pores compared to untreated soil.
Lightning Protection Methods for Wind Turbine Blades: An Alternative Approach
Authors: Mucsi Viktor , Ayub Ahmad Syahrir , Muhammad-Sukki Firdaus , Zulkipli Muhammad , Muhtazaruddin Mohd Nabil , Mohd Saudi Ahmad Shakir , Ardila-Rey Jorge Alfredo
Published: March 2020

Lightning strikes happens in a fraction of time, where they can transfer huge amounts of charge and high currents in a single strike. The chances for a structure to be struck by lightning increases as the height increases; thus, tall structures are more prone to lightning. Despite the existing lightning protection systems available for wind turbine blades, there are still many cases reported due to the fact of damage caused by lightning strike. Owing to that, the present work introduces a new approach for a lightning protection system for wind turbine blades where preliminary investigations were done using Analysis Systems (ANSYS) Workbench. Two models were developed: one with a conventional type down conductor system and the other with a hybrid conductor system. The recorded findings have been compared and discussed, where it was found that the hybrid conductor system may provide alternative protection from lightning for wind turbine blades.
From Ethnographic Research to Big Data Analytics—A Case of Maritime Energy-Efficiency Optimization
Authors: Man Yemao , Sturm Tobias , Lundh Monica , MacKinnon Scott N.
Published: March 2020

The shipping industry constantly strives to achieve efficient use of energy during sea voyages. Previous research that can take advantages of both ethnographic studies and big data analytics to understand factors contributing to fuel consumption and seek solutions to support decision making is rather scarce. This paper first employed ethnographic research regarding the use of a commercially available fuel-monitoring system. This was to contextualize the real challenges on ships and informed the need of taking a big data approach to achieve energy efficiency (EE). Then this study constructed two machine-learning models based on the recorded voyage data of five different ferries over a one-year period. The evaluation showed that the models generalize well on different training data sets and model outputs indicated a potential for better performance than the existing commercial EE system. How this predictive-analytical approach could potentially impact the design of decision support navigational systems and management practices was also discussed. It is hoped that this interdisciplinary research could provide some enlightenment for a richer methodological framework in future maritime energy research.
Open-Circuit Fault Diagnosis of Wind Power Converter Using Variational Mode Decomposition, Trend Feature Analysis and Deep Belief Network
Authors: Zhang Jingxuan , Sun Hexu , Sun Zexian , Dong Yan , Dong Weichao
Published: March 2020

The power converter is a significant device in a wind power system. The wind turbine will be shut down and off grid immediately with the occurrence of the insulated gate bipolar transistor (IGBT) module open-circuit fault of the power converter, which will seriously impact the stability of grid and even threaten personal safety. However, in the existing diagnosis strategies for the power converter there are few single and double IGBT module open-circuit fault diagnosis methods producing negative results, including erroneous judgment, omissive judgment and low accuracy. In this paper, a novel method to diagnose the single and double IGBT modules open-circuit faults of the permanent magnet synchronous generator (PMSG) wind turbine grid-side converter (GSC) is proposed: Primarily, by collecting the three-phase current varying with a wind speed of 22 states, including a normal state and 21 failure states of PMSG wind turbine GSC as the original signal data. Afterward, the original signal data are decomposed by using variational mode decomposition (VMD) to obtain the mode coefficient series, which are analyzed by the proposed method base on fault trend feature for extracting the trend feature vectors. Finally, the trend feature vectors are utilized as the input of the deep belief network (DBN) for decision-making and obtaining the classification results. The simulation and experimental results show that the proposed method can diagnose the single and double IGBT modules open-circuit faults of GSC, and the accuracy is higher than the benchmark models.
Anti-Frothing Effect of Poultry Feathers in Bio-Based, Polycondensation-Type Thermoset Composites
Authors: Brenner Markus , Popescu Crisan , Weichold Oliver
Published: March 2020

The formation of polycondensation-type thermoset resins from natural reactants such as citric and glutaric acid, as well as 1,3-propanediol and glycerol, was studied. Monitoring the mass loss by thermogravimetric analysis (TGA) allowed the rate constants of the esterification to be calculated, which were in the order of 7·10−5 s−1 for glutaric acid and approximately twice as high for citric acid. However, the combination citric acid/glycerol was previously reported to froth up at high conversions, giving rise to foams, which makes the preparation of compact engineering composites challenging. In light of this, we observed that shredded poultry feathers not only increased the conversion and the reaction rate of the combination citric acid/glycerol, but increasing the amount of feathers continuously decreased the number of visible bubbles. The addition of 20 wt% of feathers completely prevented the previously reported frothing and gave rise to compact materials that were macroscopically free of defects. Besides this, the addition of feathers also improved the fire-retardant properties. The tensile properties of the first specimens are still rather low (σ = 11.6 N/mm2, E = 750 N/mm2), but the addition of poultry feathers opens a new path for green thermoset resins.
A Method of On-Site Describing the Positional Relation between Two Horizontal Parallel Surfaces and Two Vertical Parallel Surfaces
Authors: Lu Zechen , Zhang Bao , Li Zhenjun , Zhao Chunyu
Published: March 2020

The position error of two parallel surfaces is generally constrained by parallelism. However, as a range of change, it cannot represent the positional relation between two parallel surfaces. Large-scale equipment such as machine tools are complex and difficult to move. It is also an engineering problem to perform field measurements on it. To this end, a method of describing the positional relation between two horizontal parallel surfaces and two vertical parallel surfaces on-site is proposed in this paper, which is a novel kind of position error, enriching the form of parallel surface position error, and solves the inconvenience problem of large equipment position error measurement. The measurement mechanisms are designed, and the measurement principle is given. Firstly, the combined projection waveform of the measured surface can be obtained by the geometric relationship between the measurement mechanism and the measured surface. Secondly, an algorithm is studied to process the obtained waveform, and the combined projection curve of the measured surface is acquired. Then, under the condition of considering the shape contours of the two surfaces, an algorithm is developed to acquire the calculated shape contour of the measured surface. According to the difference between the calculated surface shape contour and the known shape contour of the measured surface, the positional relation of the two surfaces can be determined. Meanwhile, the mathematical models of algorithms are established, and the measurement experiments are carried out, and the algorithms are verified by the mutual measurement method of the two surfaces. The results show that this method can accurately obtain the positional relation of two horizontal parallel surfaces and two vertical parallel surfaces.
Trends and Features of the Applications of Natural Language Processing Techniques for Clinical Trials Text Analysis
Authors: Chen Xieling , Xie Haoran , Cheng Gary , Poon Leonard K. M. , Leng Mingming , Wang Fu Lee
Published: March 2020

Natural language processing (NLP) is an effective tool for generating structured information from unstructured data, the one that is commonly found in clinical trial texts. Such interdisciplinary research has gradually grown into a flourishing research field with accumulated scientific outputs available. In this study, bibliographical data collected from Web of Science, PubMed, and Scopus databases from 2001 to 2018 had been investigated with the use of three prominent methods, including performance analysis, science mapping, and, particularly, an automatic text analysis approach named structural topic modeling. Topical trend visualization and test analysis were further employed to quantify the effects of the year of publication on topic proportions. Topical diverse distributions across prolific countries/regions and institutions were also visualized and compared. In addition, scientific collaborations between countries/regions, institutions, and authors were also explored using social network analysis. The findings obtained were essential for facilitating the development of the NLP-enhanced clinical trial texts processing, boosting scientific and technological NLP-enhanced clinical trial research, and facilitating inter-country/region and inter-institution collaborations.
Coupling and Decoupling Measurement Method of Complete Geometric Errors for Multi-Axis Machine Tools
Authors: Wang Hongwei , Ran Yan , Zhang Shengyong , Li Yulong
Published: March 2020

Precision and ultra-precision machining technology rely mainly on the machine tools’ accuracy. To improve it, the measurement, calculation, prediction and control of geometric errors are critical. The traditional measurement methods have lower precision because of ignoring small angle errors. To obtain complete geometric errors of multi-axis machine tools, this paper proposes a new method of coupling and decoupling measurement. Specifically, we used a laser interferometer and dial indicators to measure 36 items of complete geometric errors of multi-axis machine tools. A homogeneous transformation matrix (HTM) was applied to model the error transfer route. The transfer law of complete errors for each machining point was explored and derived. Furthermore, we selected and calculated integrated errors of 36 machining points. Finally, we proved the correctness of the method by comparing the measurement result of a ball bar test and coupling and decoupling measurement of geometric errors. We found that items of small geometric angle errors have a greater impact on machining accuracy than those of geometric displacement errors. Complete geometric errors measured via the coupling and decoupling measurement method can evaluate integrated errors more precisely and comprehensively.
A Causality Mining and Knowledge Graph Based Method of Root Cause Diagnosis for Performance Anomaly in Cloud Applications
Authors: Qiu Juan , Du Qingfeng , Yin Kanglin , Zhang Shuang-Li , Qian Chongshu
Published: March 2020

With the development of cloud computing technology, the microservice architecture (MSA) has become a prevailing application architecture in cloud-native applications. Many user-oriented services are supported by many microservices, and the dependencies between services are more complicated than those of a traditional monolithic architecture application. In such a situation, if an anomalous change happens in the performance metric of a microservice, it will cause other related services to be downgraded or even to fail, which would probably cause large losses to dependent businesses. Therefore, in the operation and maintenance job of cloud applications, it is critical to mine the causality of the problem and find its root cause as soon as possible. In this paper, we propose an approach for mining causality and diagnosing the root cause that uses knowledge graph technology and a causal search algorithm. We verified the proposed method on a classic cloud-native application and found that the method is effective. After applying our method on most of the services of a cloud-native application, both precision and recall were over 80%.
Gaseous Emissions from a Seagoing Ship under Different Operating Conditions in the Coastal Region of China
Authors: Bai Chunjiang , Li Ying , Liu Bingxin , Zhang Zhaoyi , Wu Peng
Published: March 2020

Pollution caused by ship emissions has drawn attention from various countries. Because of the high density of ships in ports, channels, and anchorages and their proximity to the densely populated areas, ship emissions will considerably impact these areas. Herein, a Chinese seagoing ship is selected and a platform is established for monitoring the ship emissions to obtain detailed characteristics of the ship’s nearshore emissions. The ship navigation and pollution emission data are obtained under six complete operating conditions, i.e., berthing, manoeuvring in port, acceleration in a channel, cruising, deceleration before anchoring, and anchoring. This study analyzes the concentrations of the main emission gases (O2, NOX, SO2, CO2, and CO) and the average emission factors (EFs) of the pollution gases (NOX, SO2, CO2, and CO) based on the engine power under different operating conditions. Results show that the change in O2 concentration reflects the load associated with the main engine of the ship. The NOX, SO2, and CO2 emission concentrations are the highest during cruising, whereas the peak CO emission concentration is observed during anchoring. The average EFs of NOX and SO2 based on the power of the main engine are the highest during cruising, and those of CO2 and CO are the highest after anchoring. The ship EFs are different during acceleration and deceleration. By comparing the EFs along the coast of China and the global EFs commonly used to perform the emission inventory calculations in China, the NOX EFs under different operating conditions is observed to be generally lower than the global EFs under the corresponding operating conditions. Furthermore, the SO2 EF is considerably affected by the sulfur content in the fuel oil and the operating conditions of the ship. The average CO2 EFs are higher than the global EFs commonly used during cruising, and the CO EFs are higher than the global EFs under all the conditions. Our results help to supplement the EFs for this type of ship under different operating conditions, resolve the lack of emission data under anchoring conditions, and provide data support to conduct nearshore environmental monitoring and assessment.
Spatiotemporal Trends of Aerosols over Urban Regions in Pakistan and Their Possible Links to Meteorological Parameters
Authors: Ali Gohar , Bao Yansong , Ullah Waheed , Ullah Safi , Guan Qin , Liu Xulin , Li Lin , Lei Yuhong , Li Guangwen , Ma Jun
Published: March 2020

Aerosol optical depth (AOD) has become one of the most crucial parameters for climate change assessment on regional and global scales. The present study investigates trends in AOD using long-term data derived from moderate resolution imaging spectro-radiometer (MODIS) over twelve regions in Pakistan. Different statistical tests are used to assess the annual and seasonal trends in AOD. Results reveal increasing AOD trends over most of the selected regions with an obvious increase over the north and northeastern parts of the study area. Annually, increasing trends (0.0002–0.0047 year−1) were observed over seven regions, with three being statistically significant. All the selected regions experience increasing AOD trends during the winter season with six being statistically significant while during the summer season seven regions experience increasing AOD trends and the remaining five exhibit the converse with two being statistically significant. The changes in the sign and magnitude of AOD trends have been attributed to prevailing meteorological conditions. The decreasing rainfall and increasing temperature trends mostly support the increasing AOD trend over the selected regions. The high/low AOD phases during the study period may be ascribed to the anomalies in mid-tropospheric relative humidity and wind fields. The summer season is generally characterized by high AOD with peak values observed over the regions located in central plains, which can be attributed to the dense population and enhanced concentration of industrial and vehicular emissions over this part of the study area. The results derived from the present study give an insight into aerosol trends and could form the basis for aerosol-induced climate change assessment over the study area.
Evaluation of Meteorological Drought and Flood Scenarios over Kenya, East Africa
Authors: Ayugi Brian , Tan Guirong , Niu Rouyun , Dong Zeyao , Ojara Moses , Mumo Lucia , Babaousmail Hassen , Ongoma Victor
Published: March 2020

This work examines drought and flood events over Kenya from 1981 to 2016 using the Standardized Precipitation–Evapotranspiration Index (SPEI). The spatiotemporal analysis of dry and wet events was conducted for 3 and 12 months. Extreme drought incidences were observed in the years 1987, 2000, 2006, and 2009 for SPEI-3, whilst the SPEI-12 demonstrated the manifestation of drought during the years 2000 and 2006. The SPEI showed that the wettest periods, 1997 and 1998, coincided with the El Nino event for both time steps. SPEI-3 showed a reduction in moderate drought events, while severe and extreme cases were on the increase tendencies towards the end of the twentieth century. Conversely, SPEI-12 depicted an overall increase in severe drought occurrence over the study location with ab observed intensity of −1.54 and a cumulative frequency of 64 months during the study period. Wet events showed an upward trend in the western and central highlands, while the rest of the regions showed an increase in dry events during the study period. Moreover, moderate dry/wet events predominated, whilst extreme events occurred least frequently across all grid cells. It is apparent that the study area experienced mild extreme dry events in both categories, although moderately severe dry events dominated most parts of the study area. A high intensity and frequency of drought was noted in SPEI-3, while the least occurrences of extreme events were recorded in SPEI-12. Though drought event prevailed across the study area, there was evidence of extreme flood conditions over the recent decades. These findings form a good basis for next step of research that will look at the projection of droughts over the study area based on regional climate models.
Understanding the Variability of West African Summer Monsoon Rainfall: Contrasting Tropospheric Features and Monsoon Index
Authors: Akinsanola Akintomide Afolayan , Zhou Wen
Published: March 2020

West African Summer Monsoon (WASM) rainfall exhibits large variability at interannual and decadal timescales, causing droughts and floods in many years. Therefore it is important to investigate the major tropospheric features controlling the WASM rainfall and explore its potential to develop an objective monsoon index. In this study, monthly mean reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) and monthly rainfall data from three gridded observations during the 65-year period of 1950–2014 were employed. Dry and wet rainfall years were identified using a standardized precipitation index. In a composite analysis of wet and dry years, the dynamical features controlling the WASM exhibit an obvious contrast between these years, and a weaker (stronger) African Easterly Jet (Tropical Easterly Jet) is observed during the wet years. Also, a well-developed and deep low-level westerly flow at about 850 hPa is evident in wet years while an obvious reversal is observed in dry years. Considering this, the main regions of the two easterly jet streams and low-level westerly wind are proposed for objectively defining an effective WASM index (WASMI). The results indicate that the WASMI defined herein can reflect variations in June–September rainfall over West Africa. The index exhibits most of the variabilities observed in the rainfall series, with high (low) index values occurring in the 1950–1960s (1970–1980s), suggesting that the WASMI is skilled in capturing the respective wet and dry rainfall episodes over the region. Also, the WASMI is significantly correlated (r = 0.8) with summer monsoon rainfall, which further affirms that it can indicate not only variability but also the intensity of WASM rainfall.
Oxidative Stress and Antioxidants in Atherosclerosis Development and Treatment
Authors: Poznyak Anastasia V. , Grechko Andrey V. , Orekhova Varvara A. , Chegodaev Yegor S. , Wu Wei-Kai , Orekhov Alexander N.
Published: March 2020

Atherosclerosis can be regarded as chronic inflammatory disease affecting the arterial wall. Despite the recent progress in studying the pathogenesis of atherosclerosis, some of the pathogenic mechanisms remain to be fully understood. Among these mechanisms is oxidative stress, which is closely linked to foam cells formation and other key events in atherosclerosis development. Two groups of enzymes are involved in the emergence of oxidative stress: Pro-oxidant (including NADPH oxidases, xanthine oxidases, and endothelial nitric oxide synthase) and antioxidant (such as superoxide dismutase, catalases, and thioredoxins). Pro-oxidant enzymes in normal conditions produce moderate concentrations of reactive oxidant species that play an important role in cell functioning and can be fully utilized by antioxidant enzymes. Under pathological conditions, activities of both pro-oxidant and antioxidant enzymes can be modified by numerous factors that can be relevant for developing novel therapies. Recent studies have explored potential therapeutic properties of antioxidant molecules that are capable to eliminate oxidative damage. However, the results of these studies remain controversial. Other perspective approach is to inhibit the activity of pro-oxidant enzymes and thus to slow down the progression of atherosclerosis. In this review we summarized the current knowledge on oxidative stress in atherosclerosis and potential antioxidant approaches. We discuss several important antioxidant molecules of plant origin that appear to be promising for treatment of atherosclerosis.
Keeping in Touch with Mental Health: The Orienting Reflex and Behavioral Outcomes from Calatonia
Authors: Blanchard Anita Ribeiro , Comfort William Edgar
Published: March 2020

Physical and psychological therapy based on touch has been gradually integrated into broader mental health settings in the past two decades, evolving from a variety of psychodynamic, neurobiological and trauma-based approaches, as well as Eastern and spiritual philosophies and other integrative and converging systems. Nevertheless, with the exception of a limited number of well-known massage therapy techniques, only a few structured protocols of touch therapy have been standardized and researched to date. This article describes a well-defined protocol of touch therapy in the context of psychotherapy—the Calatonia technique—which engages the orienting reflex. The orienting reflex hypothesis is explored here as one of the elements of this technique that helps to decrease states of hypervigilance and chronic startle reactivity (startle and defensive reflexes) and restore positive motivational and appetitive states.
Physi-Sorption of H2 on Pure and Boron–Doped Graphene Monolayers: A Dispersion–Corrected DFT Study
Authors: Nayyar Iffat , Ginovska Bojana , Karkamkar Abhijeet , Gennett Thomas , Autrey Thomas
Published: March 2020

High-surface-area carbons are of interest as potential candidates to store H2 for fuel–cell power applications. Earlier work has been ambiguous and inconclusive on the effect of boron doping on H2 binding energy. Here, we describe a systematic dispersion–corrected density functional theory study to evaluate the effect of boron doping. We observe some enhancement in H2 binding, due to the presence of a defect, such as terminal hydrogen or distortion from planarity, introduced by the inclusion of boron into a graphene ring, which creates hydrogen adsorption sites with slightly increased binding energy. The increase is from −5 kJ/mol H2 for the pure carbon matrix to −7 kJ/mol H2 for the boron–doped system with the boron content of ~7%. The H2 binding sites have little direct interaction with boron. However, the largest enhancement in physi-sorption energy is seen for systems, where H2 is confined between layers at a distance of about 7 Å, where the H2 binding nearly doubles to −11 kJ/mol H2. These findings suggest that interplanar nanoconfinement might be more effective in enhancing H2 binding. Smaller coronene model is shown to be beneficial for understanding the dependence of interaction energy on the structural configurations and preferential H2 binding sites.
A Short Review on Ni Based Catalysts and Related Engineering Issues for Methane Steam Reforming
Authors: Meloni Eugenio , Martino Marco , Palma Vincenzo
Published: March 2020

Hydrogen is an important raw material in chemical industries, and the steam reforming of light hydrocarbons (such as methane) is the most used process for its production. In this process, the use of a catalyst is mandatory and, if compared to precious metal-based catalysts, Ni-based catalysts assure an acceptable high activity and a lower cost. The aim of a distributed hydrogen production, for example, through an on-site type hydrogen station, is only reachable if a novel reforming system is developed, with some unique properties that are not present in the large-scale reforming system. These properties include, among the others, (i) daily startup and shutdown (DSS) operation ability, (ii) rapid response to load fluctuation, (iii) compactness of device, and (iv) excellent thermal exchange. In this sense, the catalyst has an important role. There is vast amount of information in the literature regarding the performance of catalysts in methane steam reforming. In this short review, an overview on the most recent advances in Ni based catalysts for methane steam reforming is given, also regarding the use of innovative structured catalysts.
Qualitative and Quantitative Coating Tests: A Comparison in Magnesia–Spinel Refractory Bricks
Authors: Pacheco Graziella , Gonçalves Geraldo Eduardo , Lins Vanessa
Published: March 2020

In cement processing, which involves the production of clinker in rotary kilns, the main refractories used in the transition and burning zones are magnesia–spinel bricks. These bricks present suitable chemical and thermomechanical properties, not to mention that they can be easily landfilled. Among the main wear mechanisms of these bricks in the kiln, the infiltration of alkaline salts is noteworthy and occurs through the open pores of the refractory. In this way, the coating—a clinker layer adhered to the brick surface—appears as a protection mechanism of the lining against infiltration. Thus, the objective of this investigation is to run a qualitative coating test based on the contact method, and quantitative coating test based on the sandwich method to check the suitability of the methodologies and to evaluate the coating adherence on two different magnesia–spinel bricks. It was possible to distinguish the superior adherence ability of brick B in both coatings due to the higher porosity and the presence of nonreacted ZrO2. Despite the similarity between the test results, the quantitative sandwich-coating test is preferable because it does not depend on subjective analysis.
Appropriate Buffers for Studying the Bioinorganic Chemistry of Silver(I)
Authors: Babel Lucille , Bonnet-Gómez Soledad , Fromm Katharina
Published: March 2020

Silver(I) is being largely studied for its antimicrobial properties. In parallel to that growing interest, some researchers are investigating the effect of this ion on eukaryotes and the mechanism of silver resistance of certain bacteria. For these studies, and more generally in biology, it is necessary to work in buffer systems that are most suitable, i.e., that interact least with silver cations. Selected buffers such as 4-(2-hydroxyethyl)-1-piperazineethane sulfonic acid (HEPES) were therefore investigated for their use in the presence of silver nitrate. Potentiometric titrations allowed to determine stability constants for the formation of (Ag(Buffer)) complexes. The obtained values were adapted to extract the apparent binding constants at physiological pH. The percentage of metal ions bound to the buffer was calculated at this pH for given concentrations of buffer and silver to realize at which extent silver was interacting with the buffer. We found that in the micromolar range, HEPES buffer is sufficiently coordinating to silver to have a non-negligible effect on the thermodynamic parameters determined for an analyte. Morpholinic buffers were more suitable as they turned out to be weaker complexing agents. We thus recommend the use of MOPS for studies of physiological pH.
Low Frictional MoS2/WS2/FineLPN Hybrid Layers on Nodular Iron
Authors: Kula Pior , Pietrasik Robert , Pawęta Sylwester , Rzepkowski Adam
Published: March 2020

The paper presents the new concept of low frictional hybrid composite coatings on nodular cast iron. The structure of it is multilayer and consists of MoS2 and/or WS2 nanoinclusions embedded in the iron nitrides’ zone and relatively deep hard diffusion zone. It offers a low friction coefficient as well as high wear resistance of coated parts. The details of technology as well as the mechanism of layer’s growth have been presented and discussed. The presented technology may be an interesting alternative for chromium-based galvanic coatings of piston rings made of nodular iron using Cr6+.
Effect of Electrode Covering Composition on the Microstructure, Wear, and Economic Feasibility of Fe-C-Cr Manual Arc-Welded Hardfacings
Authors: Jankauskas Vytenis , Katinas Egidijus , Laskauskas Artūras , Antonov Maksim , Varnauskas Valentinas , Gedzevičius Irmantas , Aleknevičienė Vilija
Published: March 2020

Manual arc-welded hardfacings are widely used for the protection of new or the restoration of worn parts in agriculture, forestry, and mining applications. A study was conducted to investigate the effect of electrode covering composition on the microstructure, wear (low, average stress abrasion; erosion at 30, 50, and 80 m s−1), and economic feasibility of Fe–C–Cr manual arc-welded hardfacings. Hardfacings were produced with the carbon and chrome contents varied in the ranges of 0.87–2.95 and 1.3–33.2 wt.%, respectively. The major phases composing the microstructures of the hardfacings were austenite, perlite, ledeburite, and various carbides, including eutectic M7C3. Technical and economic analyses were performed to assess the economic feasibility of hardfacings and reference wear-resistant steel Hardox 400. A wear and economic feasibility map was created to specify various types and facilitate the selection of optimal hardfacings for specific conditions. The produced Fe–C–Cr coatings were the most effective in low-stress abrasive conditions (up to 7.8 times greater than Hardox 400) and quite effective in erosive conditions (up to 2.9 times greater than Hardox 400).
Investigation of the Effect of Geometry Characteristics on Bending Stress of Asymmetric Helical Gears by Using Finite Elements Analysis
Authors: Zouridaki Andromachi-Efsevia , Vasileiou George
Published: March 2020

Asymmetric helical gears have been under investigation for more than two decades due to their inherent ability to handle greater bending loads than their spur counterparts of comparable size (i.e., the number of teeth and module). For this type of gear, only one side of each gear tooth in a geared mechanism is usually loaded (driving/driven side), whereas the other remains mostly unloaded (coast side). Due to the asymmetry of the tooth, a nonlinear model is used. For that reason, a numerical design procedure is introduced involving the geometrical and structural modelling of conjugate helical gear sets. This is accomplished with the tool of Finite Element Analysis (FEA) which is presented to the scientific literature. The basic geometry is initially generated in 2D and thereafter converted to a 3D shape using Boolean operations. The rigid body which is necessary for FEA software is produced from Computer Aided Design (CAD) software (SolidWorks). This paper is focused on the effect analysis of different geometry characteristics on bending loads. The effects on bending stress play a significant role in gear design wherein its magnitude is controlled by the nominal bending stress and the stress concentration due to the geometrical shape of the teeth. The analysis of this effect of the different geometrical characteristics in the load is presented in detail. Moreover, a comparison of the stresses that are developed between pairs with asymmetrical helical teeth by keeping one geometric parameter constant and modifying the values of the other two parameters is presented.
Introduction to the Special Issue “Applications in Self-Aware Computing Systems and their Evaluation”
Authors: Krupitzer Christian , Eberhardinger Benedikt , Gerostathopoulos Ilias , Raibulet Claudia
Published: March 2020

The joint 1st Workshop on Evaluations and Measurements in Self-Aware Computing Systems (EMSAC 2019) and Workshop on Self-Aware Computing (SeAC) was held as part of the FAS* conference alliance in conjunction with the 16th IEEE International Conference on Autonomic Computing (ICAC) and the 13th IEEE International Conference on Self-Adaptive and Self-Organizing Systems (SASO) in Umeå, Sweden on 20 June 2019. The goal of this one-day workshop was to bring together researchers and practitioners from academic environments and from the industry to share their solutions, ideas, visions, and doubts in self-aware computing systems in general and in the evaluation and measurements of such systems in particular. The workshop aimed to enable discussions, partnerships, and collaborations among the participants. This special issue follows the theme of the workshop. It contains extended versions of workshop presentations as well as additional contributions.
Transition Metal Dichalcogenides as Strategy for High Temperature Electron-Hole Superfluidity
Authors: Conti Sara , Neilson David , Peeters François M. , Perali Andrea
Published: March 2020

Condensation of spatially indirect excitons, with the electrons and holes confined in two separate layers, has recently been observed in two different double layer heterostructures. High transition temperatures were reported in a double Transition Metal Dichalcogenide (TMD) monolayer system. We briefly review electron-hole double layer systems that have been proposed as candidates for this interesting phenomenon. We investigate the double TMD system WSe 2 /hBN/MoSe 2 , using a mean-field approach that includes multiband effects due to the spin-orbit coupling and self-consistent screening of the electron-hole Coulomb interaction. We demonstrate that the transition temperature observed in the double TMD monolayers, which is remarkably high relative to the other systems, is the result of (i) the large electron and hole effective masses in TMDs, (ii) the large TMD band gaps, and (iii) the presence of multiple superfluid condensates in the TMD system. The net effect is that the superfluidity is strong across a wide range of densities, which leads to high transition temperatures that extend as high as T B K T = 150 K.
On Quantum Chosen-Ciphertext Attacks and Learning with Errors
Authors: Alagic Gorjan , Jeffery Stacey , Ozols Maris , Poremba Alexander
Published: March 2020

Large-scale quantum computing poses a major threat to classical public-key cryptography. Recently, strong “quantum access” security models have shown that numerous symmetric-key cryptosystems are also vulnerable. In this paper, we consider classical encryption in a model that grants the adversary quantum oracle access to encryption and decryption, but where we restrict the latter to non-adaptive (i.e., pre-challenge) queries only. We formalize this model using appropriate notions of ciphertext indistinguishability and semantic security (which are equivalent by standard arguments) and call it QCCA 1 in analogy to the classical CCA 1 security model. We show that the standard pseudorandom function ( PRF )-based encryption schemes are QCCA 1 -secure when instantiated with quantum-secure primitives. Our security proofs use a strong bound on quantum random-access codes with shared randomness. Revisiting plain IND − CPA -secure Learning with Errors ( LWE ) encryption, we show that leaking only a single quantum decryption query (and no other leakage or queries of any kind) allows the adversary to recover the full secret key with constant success probability. Information-theoretically, full recovery of the key in the classical setting requires at least a linear number of decryption queries. Our results thus challenge the notion that LWE is unconditionally “just as secure” quantumly as it is classically. The algorithm at the core of our attack is a new variant of the well-known Bernstein–Vazirani algorithm. Finally, we emphasize that our results should not be interpreted as a weakness of these cryptosystems in their stated security setting (i.e., post-quantum chosen-plaintext secrecy). Rather, our results mean that, if these cryptosystems are exposed to chosen-ciphertext attacks (e.g., as a result of deployment in an inappropriate real-world setting) then quantum attacks are even more devastating than classical ones.
Transmission Characteristics of Ultrasonic Longitudinal Wave Signals in Negative Refractive Index Materials
Authors: Geng Yixue , Sun Yunqiang , Yang Peng , Liu Xin , Han Jianning
Published: March 2020

Longitudinal waves have important applications in modern scientific research and production; as a special acoustic wave, longitudinal waves have a sound transmission performance in negative refractive index materials. This paper has designed a new structure for negative refractive index materials by virtue of COMSOL software and conducted related simulation analysis. Experimental results illustrated that the structure designed had good acoustic longitudinal wave transmission performance. Besides, the effect of sound wave focusing could be achieved by a combination of existing test methods. The design proposed could break the limitation of previous structures on acoustic longitudinal wave transmission. This study is expected to have important implications for the development of solid metamaterial structures.
Variability and Community Composition of Marine Unicellular Eukaryote Assemblages in a Eutrophic Mediterranean Urban Coastal Area with Marked Plankton Blooms and Red Tides
Authors: Genitsaris Savvas , Stefanidou Natassa , Moustaka-Gouni Maria , Sommer Ulrich , Tsipas George
Published: March 2020

The Thessaloniki Bay is a eutrophic coastal area which has been characterized in recent years by frequent and intense phytoplankton blooms and red tides. The aim of the study was to investigate the underexplored diversity of marine unicellular eukaryotes in four different sampling sites in Thessaloniki Bay during a year of plankton blooms, red tides, and mucilage aggregates. High-Throughput Sequencing (HTS) was applied in extracted DNA from weekly water samples targeting the 18S rRNA gene. In almost all samples, phytoplankton blooms and/or red tides and mucilage aggregates were observed. The metabarcoding analysis has detected the known unicellular eukaryotic groups frequently observed in the Bay, dominated by Bacillariophyta and Dinoflagellata, and revealed taxonomic groups previously undetected in the study area (MALVs, MAST, and Cercozoa). The dominant OTUs were closely related to species known to participate in red tides, harmful blooms, and mucilage aggregates. Other OTUs, present also during the blooms in low abundance (number of reads), were closely related to known harmful species, suggesting the occurrence of rare taxa with potential negative impacts on human health not detectable with classical microscopy. Overall, the unicellular eukaryote assemblages showed temporal patterns rather than small-scale spatial separation responding to the variability of physical and chemical factors.
Simultaneous Measurement of Gastric Emptying of a Soup Test Meal Using MRI and Gamma Scintigraphy
Authors: Khalaf Asseel , Hoad Caroline L. , Blackshaw Elaine , Alyami Jaber , Spiller Robin C. , Gowland Penny A. , Vinayaka-Moorthy Vidhiya , Perkins Alan C. , Moran Gordon W. , Marciani Luca
Published: March 2020

Measurement of gastric emptying is of clinical value for a range of conditions. Gamma scintigraphy (GS) has an established role, but the use of magnetic resonance imaging (MRI) has recently increased. Previous comparison studies between MRI and GS showed good correlation, but were performed on separate study days. In this study, the modalities were alternated rapidly allowing direct comparison with no intra-individual variability confounds. Twelve healthy participants consumed 400 g of Technetium-99m (99mTc)-labelled soup test meal (204 kcal) and were imaged at intervals for 150 min, alternating between MRI and GS. The time to empty half of the stomach contents (T1/2) and retention rate (RR) were calculated and data correlated. The average T1/2 was similar for MRI (44 ± 6 min) and GS (35 ± 4 min) with a moderate but significant difference between the two modalities (p < 0.004). The individual T1/2 values were measured, and MRI and GS showed a good positive correlation (r = 0.95, p < 0.0001), as well as all the RRs at each time point up to 120 min. Gastric emptying was measured for the first time by MRI and GS on the same day. This may help with translating the use of this simple meal, known to elicit reliable, physiological, and pathological gastrointestinal motor, peptide, and appetite responses.
Use of the Serum Wisteria floribunda Agglutinin-Positive Mac2 Binding Protein as a Marker of Gastroesophageal Varices and Liver-Related Events in Chronic Hepatitis C Patients
Authors: Hayashi Tsuguru , Tamaki Nobuharu , Kurosaki Masayuki , Wang Wan , Okada Mao , Higuchi Mayu , Takaura Kenta , Takada Hitomi , Yasui Yutaka , Tsuchiya Kaoru , Nakanishi Hiroyuki , Itakura Jun , Harada Masaru , Izumi Namiki
Published: March 2020

Background: A test to narrow down patients who require esophagogastroduodenoscopy (EGD) with a high probability of having gastroesophageal varices (GEV) and a high-risk of liver-related events is an unmet need. Methods: The measurement of serum fibrosis markers and EGD was performed in 166 consecutive chronic hepatitis C patients. The correlation between the grades of GEV and fibrosis markers and the subsequent occurrence of liver-related and fibrosis markers were examined. Results: Wisteria floribunda agglutinin-positive human Mac-2 binding protein (WFA+–M2BP) levels increased according to the grade of GEV (3.4 (0.2–18.6) for no GEV, 7.9 (1.8–20.0) for small GEV, and 11.4 (4.0–20.0) for large GEV; p < 0.001). The diagnostic accuracy of the WFA+–M2BP was superior compared to other serum fibrosis markers, and WFA+–M2BP was an independent predictor of GEV in the multivariate analysis. Furthermore, the cumulative incidence of liver-related events at one year was 2.3% in patients with WFA+–M2BP levels ≤ 7.0 and 37.5% in patients with WFA+–M2BP levels > 7.0 (p < 0.001). WFA+–M2BP > 7.0 was a significant predictive factor for liver-related events (Hazard ratio 6.7, p = 0.004) independent of Child–Pughclass. Conclusions: WFA+–M2BP could be used to estimate the presence and grade of GEV and is linked to liver-related events in chronic hepatitis C patients.