bluuebunny/crossref_metadata_2025 huggingface dataset:
Photophysics and Photochemistry of Iron Carbene Complexes for Solar Energy Conversion and Photocatalysis
Authors: Lindh Linnea , Chábera Pavel , Rosemann Nils W. , Uhlig Jens , Wärnmark Kenneth , Yartsev Arkady , Sundström Villy , Persson Petter
Published: March 2020

Earth-abundant first row transition metal complexes are important for the development of large-scale photocatalytic and solar energy conversion applications. Coordination compounds based on iron are especially interesting, as iron is the most common transition metal element in the Earth’s crust. Unfortunately, iron-polypyridyl and related traditional iron-based complexes generally suffer from poor excited state properties, including short excited-state lifetimes, that make them unsuitable for most light-driven applications. Iron carbene complexes have emerged in the last decade as a new class of coordination compounds with significantly improved photophysical and photochemical properties, that make them attractive candidates for a range of light-driven applications. Specific aspects of the photophysics and photochemistry of these iron carbenes discussed here include long-lived excited state lifetimes of charge transfer excited states, capabilities to act as photosensitizers in solar energy conversion applications like dye-sensitized solar cells, as well as recent demonstrations of promising progress towards driving photoredox and photocatalytic processes. Complementary advances towards photofunctional systems with both Fe(II) complexes featuring metal-to-ligand charge transfer excited states, and Fe(III) complexes displaying ligand-to-metal charge transfer excited states are discussed. Finally, we outline emerging opportunities to utilize the improved photochemical properties of iron carbenes and related complexes for photovoltaic, photoelectrochemical and photocatalytic applications.
Correlation of Thermo-Elastic Material and Corrosion Behavior of Refractory Castables by In-Situ Measurements
Authors: Reichert Wanja , Nießen Jonas , Leto Peter , Etzold Simon , Kröll Eva , Tonnesen Thorsten , Telle Rainer
Published: March 2020

Corrosion is one of the most common wear mechanisms of refractories. Corrosive attacks lead to chemical and microstructural changes. Hot corrosion compromises chemical and/or physical interactions. Thus, the process is complex and not yet fully understood. Currently, corrosion is investigated post mortem by means of X-ray diffraction or scanning electron microscopy. These methods have the drawback that some information is lost on cooling. In-situ measurements, however, take measurements within the process. In resonant frequency and damping analysis (RFDA), a sample is excited to vibrate by a mechanical impulse. The vibrating sample emits an acoustic signal. This is recorded with a microphone and evaluated by means of Fast Fourier Transformation (FFT). We measured the change of the frequency of a low cement castable during the corrosion process. Further simplified experiments with less complex materials were done to confirm the results. Distinctive points of the curves could be correlated to specific corrosion phenomena, like melting or infiltration. The applied methods include a first characterization of the material with open porosity, density and in-situ high-temperature (HT)-RFDA measurements as well as a study of the slag behavior.
Dry Reforming of Methane over a Ruthenium/Carbon Nanotube Catalyst
Authors: Zhu Yuan , Chen Kun , Barat Robert , Mitra Somenath
Published: March 2020

In this study, CH4 dry reforming was demonstrated on a novel microwave-synthesized ruthenium (Ru)/carbon nanotube (CNT) catalyst. The catalyst was tested in an isothermal laboratory-packed bed reactor, with gas analysis by gas chromatography/thermal conductivity detection. The catalyst demonstrated excellent dry-reforming activity at modest temperatures (773–973 K) and pressure (3.03 × 105 Pa). Higher reaction temperatures favored increased conversion of CH4 and CO2, and increased H2/CO product ratios. Slight coke deposition, estimated by carbon balance, was observed at higher temperatures and higher feed CH4/CO2. A robust global kinetic model composed of three reversible reactions—dry reforming, reverse water gas shift, and CH4 decomposition—simulates observed outlet species concentrations and reactant conversions using this Ru/CNT catalyst over the temperature range of this study. This engineering kinetic model for the Ru/CNT catalyst predicts a somewhat higher selectivity and yield for H2, and less for CO, in comparison to previously published results for a similarly prepared Pt_Pd/CNT catalyst from our group.
Thermal Mode Optimization of Combustion Chamber Walls for Power-Plants Using Semitransparent Porous Ceramics
Authors: Merzlikin Vladimir , Bystrov Andrei , Minashkin Vitaly , Marynenko Vladimir , Zagumennov Fedor
Published: March 2020

The paper examines control and management by thermal mode of the internal surface of heat-insulated combustion chamber walls for green & efficient diesel and gas turbine engines due to the application of opaque or semitransparent thermal barrier materials (coatings). The authors’ model is devoted to combined radiant heat transfer both inside the heat-insulated combustion chamber and its ceramics walls, which could be scattering and absorbing for penetrating radiant component in the subsurface volume of optically heterogeneous porous material. The influence of thermal conduction, scattering (absorption) and external convective effects on the increase of the internal overheating zone in subsurface layers is simulated under intensive radiation. The unique set of optical, thermal-physical and mechanical properties of structural ceramics, depending on their porosity, were first proposed. The radiation fields of the absorbed energy in the near IR region and the corresponding temperature distributions in the modeled opaque and semitransparent ceramics walls were calculated under a stationary radiant-convective heat load during the active combustion phase at time intervals 0.01…0.1 s (diesel engines) and 10...100 s (turbine ones). In order to control the emission of nitrogen oxides, the authors propose a generation model of NOx, its growth or reduction caused by the management of radiant overheating inside semitransparent heat-insulation in which surface temperature is due to volumetric radiant absorption. It is shown that for semitransparent materials (coatings), the optimal thermal mode is determined first of all by thermal radiant characteristics in near IR at heating small times and it begins to correct at long ones due to the effect of thermal conductivity. This process may be modeled and regulated by the selected microstructural porosity of ceramic heat insulation.
Effect of Nano-Edible Coating Based on Beeswax Solid Lipid Nanoparticles on Strawberry’s Preservation
Authors: Zambrano-Zaragoza Maria L. , Quintanar-Guerrero David , Del Real Alicia , González-Reza Ricardo M. , Cornejo-Villegas Maria A. , Gutiérrez-Cortez Elsa
Published: March 2020

Edible nano-coatings were applied in strawberry with the end goal of preserving quality by 21 days of storage at 4 °C. The beeswax solid lipid nanoparticles (BSLN) were prepared by high-energy homogenization, BSLN had a monomodal dispersion with average particle sizes of 214–227 nm and zeta potential of −30 mV. Four coatings were tested: 0, 10, 20, and 30 g/L of BSLN dispersion, all these edible coatings contained xanthan gum (XG) (3 g/L) and propylene glycol (5 g/L) and contrasted with strawberries without any treatment. The best behavior was achieved with 10 g/L of BSLN showing the lowest weight loss (6.1%), a decay index of (31%), loss of firmness (34%), and ΔE = 11. It was established that a concentration of 30 g/L of BSLN caused physiological damage. Based on the findings found, it can be said that nano-coatings with 10 g/L of BSLN-XG are an excellent alternative in the conservation and to increase of shelf life of strawberry stored in refrigeration. In the present case, it was 10 g/L of BSL. Highlighting the importance to evaluate the best concentration in relation to the fruit characteristics.
Biocompatibility Evaluation and Enhancement of Elastomeric Coatings Made Using Table-Top Optical 3D Printer
Authors: Grigaleviciute Giedre , Baltriukiene Daiva , Bukelskiene Virginija , Malinauskas Mangirdas
Published: March 2020

In this experimental report, the biocompatibility of elastomeric scaffold structures made via stereolithography employing table-top 3D printer Ember (Autodesk) and commercial resin FormLabs Flexible (FormLabs) was studied. The samples were manufactured using the standard printing and development protocol, which is known to inherit cytotoxicity due to remaining non-polymerized monomers, despite the polymerized material being fully biocompatible. Additional steps were taken to remedy this problem: the fabricated structures were soaked in isopropanol and methanol under different conditions (temperature and duration) to leach out the non-polymerized monomers. In addition, disc-shaped 3D-printed structures were UV exposed to assure maximum polymerization degree of the material. Post-processed structures were seeded with myogenic stem cells and the number of live cells was evaluated as an indicator for the material biocompatibility. The straightforward post-processing protocol enhanced the biocompatibility of the surfaces by seven times after seven days soaking in isopropanol and methanol and was comparable to control (glass and polystyrene) samples. This proposes the approach as a novel and simple method to be widely applicable for dramatic cytotoxicity reduction of optically 3D printed micro/nano-scaffolds for a wide range of biomedical studies and applications.
Films of Chitosan and Aloe vera for Maintaining the Viability and Antifungal Activity of Lactobacillus paracasei TEP6
Authors: Barragán-Menéndez Carolina , Gálvez-López Didiana , Rosas-Quijano Raymundo , Salvador-Figueroa Miguel , Ovando-Medina Isidro , Vázquez-Ovando Alfredo
Published: March 2020

The present study aimed to evaluate the effect of Aloe vera addition on the viability and antifungal activity of TEP6 (Lactobacillus paracasei) bacteria immobilized on chitosan films for 28 days. Different chitosan and A. vera proportions and carbon sources at several pH values were tested as formulations for supporting the microorganism. Bacterial viability was maintained in freshly made films, with values of 10.4, 10.8 and 10.9 log CFU·g−1 for the formulations containing 70% (T11), 100% (T8) and 100% (T16) of A. vera, respectively. The same formulations (T8, T11 and T16) maintained bacterial viability for 14 days of film storage with a loss to values of 9.5 log CFU·g−1. By applying a quarter fraction 25–2 experimental design with an array of five factors, the factors with the greatest influence on viability and antifungal activity were determined. The optimal conditions for viability were the formulation with 100% A. vera, pH 4.5 and 0.1 M glucose. The antifungal activity of fresh films was influenced by the formulation with 10 g·L−1 glycerol and 100% A. vera, showing a 60% inhibition of fungal (Colletotrichum gloeosporioides) growth. The films developed in this study may have the potential to be used as coatings on vegetal products susceptible to attack by Colletotrichum gloesporioides.
A Technical Review on Development of an Advanced Electromechanical System
Authors: Taghavi Nazita , Luecke Greg R. , Jeffery Nicholas D.
Published: March 2020

Development of an advanced electromechanical system requires a blend of technical expertise and knowledge, from electrical and mechanical engineering to software and system engineering. Engineers working in this field must be able to understand and analyze the interrelated electrical and mechanical components, as well as computer controlling programs, to communicate with each system part. In this paper, we aim to review the requirements and technical knowledge for development of these new technologies.
Effect of Zn Doping in CuO Octahedral Crystals towards Structural, Optical, and Gas Sensing Properties
Authors: Goyal Chandra Prakash , Goyal Deepak , K. Rajan Sinjumol , Ramgir Niranjan S. , Shimura Yosuke , Navaneethan Mani , Hayakawa Yasuhiro , Muthamizhchelvan C. , Ikeda Hiroya , Ponnusamy S.
Published: March 2020

Monodispersed CuO octahedral crystals were successfully synthesized using a low-temperature co-precipitation method. Zinc doping in CuO created surface defects that enhanced oxygen adsorption on the surface crucial for gas sensing applications. Pure and Zn-doped CuO sensor films were realized using the doctor blade method. The sensor films showed selective response towards a low concentration of NO2 at a lower operating temperature of 150 °C. Doping with Zn causes the resistance of the sensor film to decrease due to the enhancement of charge carriers with an analogous improvement in the sensor response. The observed decrease in sensor resistance agreed well with the findings of the work function studies. Zinc doping resulted in an increase in work function by 180 meV which, after NO2 exposure, was found to increase by a further 130 meV, attributed to the oxidizing behavior of the test gas.
LPE Growth of Composite Thermoluminescent Detectors Based on the Lu3−xGdxAl5O12:Ce Single Crystalline Films and YAG:Ce Crystals
Authors: Witkiewicz-Lukaszek Sandra , Mrozik Anna , Gorbenko Vitalii , Zorenko Tetiana , Bilski Pawel , Fedorov A. , Zorenko Yuriy
Published: March 2020

This work is dedicated to the development of new types of composite thermoluminescent (TL) detectors for simultaneous registration of the different components of ionization radiation based on the single crystalline films (SCFs) of Ce3+-doped Lu3−xGdxAl5O12:Ce (x = 0–1.5) garnet and Y3Al5O12:Ce (YAG:Ce) substrates using the liquid phase epitaxy (LPE) growth method. For this purpose, the TL properties of the mentioned epitaxial structures were examined in Risø TL/OSL-DA-20 reader under excitation by α- and β-particles from 242Am and 90Sr-90Y sources. We have shown that the cation engineering of SCF content can result in more significant separation of the TL glow curves of SCFs and substrates under α- and β-particle excitations in comparison with the prototype of such composite detectors based on the Lu3Al5O12:Ce (LuAG:Ce)/YAG:Ce epitaxial structure. Specifically, the difference between the TL glow curves of Lu1.5Gd1.5Al5O12:Ce SCFs and YAG:Ce substrates increases up to 120 K in comparison with a respective value of 80 degrees in the prototype based on the LuAG:Ce/YAG:Ce epitaxial structure. Therefore, the LPE-grown epitaxial structures containing Lu1.5Gd1.5Al5O12:Ce SCFs and Ce3+-doped YAG:Ce substrate can be successfully applied for simultaneous registration of α- and β-particles in mixed fluxes of ionization radiation.
Effect of the Fluorine Substitution for –OH Group on the Luminescence Property of Eu3+ Doped Hydroxyapatite
Authors: Zhang Xiaojun , Xing Qingguo , Liao Lixuan , Han Yingchao
Published: March 2020

In this study, different fluoridated hydroxyapatite doped with Eu3+ ion nanoparticles were prepared by the hydrothermal method. The relationship between luminescence enhancement of Eu3+ ions and a fluorine substitution ratio for hydroxyl group in hydroxyapatite was discussed. Moreover, the effect of fluorine substitution for a hydroxyl group on phase composition, crystallinity, and crystal size was studied. Phase composition and chemical structures were identified by X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) Spectroscopy analyses. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) patterns were performed to analyze the morphology and particle size. X-ray Photoelectron Spectroscopy (XPS) patterns were observed to analyze fluorine substitution for the hydroxyl group and chemical state of Eu3+ ions in fluoridated hydroxyapatite. The results of these experiments indicated that the samples with a different fluorine substitution ratio were prepared successfully by maintaining the apatite structure. With an increasing fluorine substitution ratio, the morphology maintained a rod-like structure but the aspect ratio tended to decrease. XPS patterns displayed that the fluorine replaced the hydroxyl group and brought environmental variation. The fluorine ions could affect the crystal field environment and promote luminescence conversion. There was a linear relationship between the fluorine substitution ratio and luminescence enhancement.
Intrusion Detection Based on Spatiotemporal Characterization of Cyberattacks
Authors: Kim Jiyeon , Kim Hyong S.
Published: March 2020

As attack techniques become more sophisticated, detecting new and advanced cyberattacks with traditional intrusion detection techniques based on signature and anomaly is becoming challenging. In signature-based detection, not only do attackers bypass known signatures, but they also exploit unknown vulnerabilities. As the number of new signatures is increasing daily, it is also challenging to scale the detection mechanisms without impacting performance. For anomaly detection, defining normal behaviors is challenging due to today’s complex applications with dynamic features. These complex and dynamic characteristics cause much false positives with a simple outlier detection. In this work, we detect intrusion behaviors by looking at number of computing elements together in time and space, whereas most of existing intrusion detection systems focus on a single element. In order to define the spatiotemporal intrusion patterns, we look at fundamental behaviors of cyberattacks that should appear in any possible attacks. We define these individual behaviors as basic cyberattack action (BCA) and develop a stochastic graph model to represent combination of BCAs in time and space. In addition, we build an intrusion detection system to demonstrate the detection mechanism based on the graph model. We inject numerous known and possible unknown attacks comprising BCAs and show how the system detects these attacks and how to locate the root causes based on the spatiotemporal patterns. The characterization of attacks in spatiotemporal patterns with expected essential behaviors would present a new effective approach to the intrusion detection.
Modeling and Stability Analysis of Parallel Inverters in Island Microgrid
Authors: Wang Xiaohuan , Qing Hongyang , Huang Peng , Zhang Chunjiang
Published: March 2020

The island microgrid is composed of a large number of inverters and various types of power equipment, and the interaction between inverters with different control methods may cause system instability, which will cause the power equipment to malfunction. Therefore, effective methods for analyzing the stability of the microgrid system have become particularly important. Generally, impedance modeling methods are used to analyze the stability of power electronic converter systems. In this paper, the impedance models of a PQ-controlled inverter and droop-controlled inverter are established in d-q frame. In view of the difference of output characteristics between the two control methods, the island microgrid is equivalent to a double closed-loop system. The impedance model of the parallel system is derived and the open loop transfer function of the system is extracted. Based on the generalized Nyquist criterion (GNC), the stability of parallel system working in island microgrid mode is analyzed using this proposed impedance model. The simulation and experiment results are presented to verify the analysis.
One Step Greener: Reducing 5G and Beyond Networks’ Carbon Footprint by 2-Tiering Energy Efficiency with CO2 Offsetting
Authors: Gonçalves Luís Carlos , Sebastião Pedro , Souto Nuno , Correia Américo
Published: March 2020

Fifth generation (5G) and Beyond-5G (B5G) will be characterized by highly dense deployments, both on network plane and user plane. Internet of Things, massive sensor deployments and base stations will drive even more energy consumption. User behavior towards mobile service usage is witnessing a paradigm shift with heavy capacity, demanding services resulting in an increase of both screen time and data transfers, which leads to additional power consumption. Mobile network operators will face additional energetic challenges, mainly related to power consumption and network sustainability, starting right in the planning phase with concepts like energy efficiency and greenness by design coming into play. The main contribution of this work is a two-tier method to address such challenges leading to positively-offset carbon dioxide emissions related to mobile networks using a novel approach. The first tier contributes to overall power reduction and optimization based on energy efficient methods applied to 5G and B5G networks. The second tier aims to offset the remaining operational power usage by completely offsetting its carbon footprint through geosequestration. This way, we show that the objective of minimizing overall networks’ carbon footprint is achievable. Conclusions are drawn and it is shown that carbon sequestration initiatives or program adherence represent a negligible cost impact on overall network cost, with the added value of greener and more environmentally friendly network operation. This can also relieve the pressure on mobile network operators in order to maximize compliance with environmentally neutral activity.
Sand Seas and Dune Fields of Egypt
Authors: Bubenzer Olaf , Embabi Nabil S. , Ashour Mahmoud M.
Published: March 2020

The article reviews the state of knowledge about distribution, sizes, dynamics, and ages of all sand seas (N = 6) and dune fields (N = 10) in Egypt (1,001,450 km2). However, chronological data (Optically Stimulated Luminescence, Thermoluminescence), used in the INQUA (International Union for Quaternary Research) dune database, only exists from three of the five sand seas located in the Western Desert of Egypt. The North Sinai Sand Sea and four of the ten dune fields are located near the Nile Valley, the delta or the coast and therefore changed drastically due to land reclamation during the last decades. Here, but also in the oases, their sands pose a risk for settlements and farmland. Our comprehensive investigations of satellite images and our field measurements show that nearly all terrestrial dune forms can be observed in Egypt. Longitudinal dunes and barchans are dominant. Sand seas cover about 23.8% (with an average sand coverage of 74.8%), dune fields about 4.4% (with an average sand coverage of 31.7%) of its territory. For the Great Sand Sea and the Farafra Sand Sea, situated in the central and northern part of the Western Desert, a Late Glacial transformation by strong westerlies was found, but not for the Selima Sand Sea, situated in the south of Egypt. Regarding the sparse chronological data up to now, for a reasonable estimation of future sand mobility in the course of global climate change, further data are essential. Finally, further studies concerning sand mobility, local wind systems, and land use are needed.
Progressive Failure Analysis of a Concrete Dam Anchored with Passive Rock Bolts
Authors: Hellgren Rikard , Malm Richard , Ansell Anders
Published: March 2020

Passive rock bolts are commonly used to anchor concrete dams, and they may have a significant impact on stability-evaluations. However, these bolts are often omitted from dam safety analysis due to uncertainties regarding their condition and the size of displacements required in the dam-rock interface to mobilize significant bearing forces in the passive rock bolts. This paper address the latter question by studying the failure process of a small concrete dam anchored with rock bolts. Failure simulations were performed with the increased density method in a finite element model consisting of a dam, the corresponding part of the rock and rock bolts. Two types of approaches are used to simulate the anchorage of the rock bolts; a method where the anchorage to the rock is simulated using a fixed boundary condition; and a method where the anchoring of the bolts are modelled using springs. Depending on the method of analysis, the rock bolts contribute with 40–75% of the load-carrying capacity of the dam. The rock bolts increase the load-bearing capacity of the dam, partly through anchorage forces, but also by keeping the contact surface between rock and concrete together and thereby increase the shear capacity of the interface.
Structure and Dielectric Properties of Electroactive Tetraaniline Grafted Non-Polar Elastomers
Authors: Ellingford Christopher , Pengchaicharoen Atcharaporn , Wemyss Alan M. , Wan Chaoying
Published: March 2020

Intrinsic modification of polybutadiene and block copolymer styrene–butadiene–styrene with the electrically conducting emeraldine salt of tetraaniline (TANI) via a three-step grafting method, is reported in this work. Whilst the TANI oligomer grafted at a similar rate to both polybutadiene and styrene–butadiene–styrene under the same conditions, the resulting elastomers exhibited vastly different properties. 1 mol% TANI-PB exhibited an increased relative permittivity of 5.9, and a high strain at break of 156%, whilst 25 mol% TANI-SBS demonstrated a relative permittivity of 6.2 and a strain at break of 186%. The difference in the behaviour of the two polymers was due to the compatibilisation of TANI by styrene in SBS through π-π stacking, which prevented the formation of a conducting TANI network in SBS at. Without the styrene group, TANI-PB formed a phase separated structure with high levels of TANI grafting. Overall, it was concluded that the polymer chain structure, the morphology of the modified elastomers, and the degree of grafting of TANI, had the greatest effect on the mechanical and dielectric properties of the resultant elastomers. This work paves the way for an alternative approach to the extrinsic incorporation of conducting groups into unsaturated elastomers, and demonstrates dielectric elastomers with enhanced electrical properties for use in actuation devices and energy harvesting applications.
Game of Tissues: How the Epidermis Thrones C. elegans Shape
Authors: Carvalho Cátia A. , Broday Limor
Published: March 2020

The versatility of epithelial cell structure is universally exploited by organisms in multiple contexts. Epithelial cells can establish diverse polarized axes within their tridimensional structure which enables them to flexibly communicate with their neighbors in a 360° range. Hence, these cells are central to multicellularity, and participate in diverse biological processes such as organismal development, growth or immune response and their misfunction ultimately impacts disease. During the development of an organism, the first task epidermal cells must complete is the formation of a continuous sheet, which initiates its own morphogenic process. In this review, we will focus on the C. elegans embryonic epithelial morphogenesis. We will describe how its formation, maturation, and spatial arrangements set the final shape of the nematode C. elegans. Special importance will be given to the tissue-tissue interactions, regulatory tissue-tissue feedback mechanisms and the players orchestrating the process.
How Much g Is in the Distractor? Re-Thinking Item-Analysis of Multiple-Choice Items
Authors: Forthmann Boris , Förster Natalie , Schütze Birgit , Hebbecker Karin , Flessner Janis , Peters Martin T. , Souvignier Elmar
Published: March 2020

Distractors might display discriminatory power with respect to the construct of interest (e.g., intelligence), which was shown in recent applications of nested logit models to the short-form of Raven’s progressive matrices and other reasoning tests. In this vein, a simulation study was carried out to examine two effect size measures (i.e., a variant of Cohen’s ω and the canonical correlation RCC) for their potential to detect distractors with ability-related discriminatory power. The simulation design was adopted to item selection scenarios relying on rather small sample sizes (e.g., N = 100 or N = 200). Both suggested effect size measures (Cohen’s ω only when based on two ability groups) yielded acceptable to conservative type-I-error rates, whereas, the canonical correlation outperformed Cohen’s ω in terms of empirical power. The simulation results further suggest that an effect size threshold of 0.30 is more appropriate as compared to more lenient (0.10) or stricter thresholds (0.50). The suggested item-analysis procedure is illustrated with an analysis of twelve Raven’s progressive matrices items in a sample of N = 499 participants. Finally, strategies for item selection for cognitive ability tests with the goal of scaling by means of nested logit models are discussed.
Solid State Recycling of Aluminum Alloy Chips via Pulsed Electric Current Sintering
Authors: Cislo Clemens Nikolaus , Kronthaler Bernhard , Buchmayr Bruno , Weiß Christian
Published: March 2020

Based on high energy demand of the primary production and losses during secondary production, alternative recycling of aluminum becomes a popular research topic. Compared to both primary and secondary production of aluminum, solid state recycling offers energy savings and reduced material losses during processing by surpassing an inefficient melting step. In this work, a direct recycling route for machining chips via pulsed electric current sintering (PECS) is evaluated. Therefore, necessary processing steps for a complete recycling route are briefly outlined. After cleansing, EN AW 6082 chips, provided by Neuman Aluminium GmbH, Marktl, Austria, are compacted with variable loads and consolidated via PECS on two separate systems to enable a comparison. Produced specimens are examined with density measurements, optical microscopy and the bonding quality is evaluated by Vickers micro-hardness measurements. In combination with elevated temperature and deformation, applied current promotes consolidation amongst chips and improvements in density, hardness and microstructure are achieved. The results of this work clearly show a positive effect of PECS on the bonding amongst chips, but further research will be necessary to separate and understand influences of single processing parameters. Additionally, all processing steps from collection to consolidation have to be taken into account to achieve industrial implementation.
Highly Efficient Composite Flame Retardants for Improving the Flame Retardancy, Thermal Stability, Smoke Suppression, and Mechanical Properties of EVA
Authors: Liu Yilin , Li Bin , Xu Miaojun , Wang Lili
Published: March 2020

Ethylene vinyl acetate (EVA) copolymer has been used extensively in many fields. However, EVA is flammable and releases CO gas during burning. In this work, a composite flame retardant with ammonium polyphosphate (APP), a charring–foaming agent (CFA), and a layered double hydroxide (LDH) containing rare-earth elements (REEs) was obtained and used to improve the flame retardancy, thermal stability, and smoke suppression for an EVA matrix. The thermal analysis showed that the maximum thermal degradation temperature of all composites increased by more than 37 °C compared with that of pure EVA. S-LaMgAl/APP/CFA/EVA, S-CeMgAl/APP/CFA/EVA, and S-NdMgAl/APP/CFA/EVA could achieve self-extinguishing behavior according to the UL-94 tests (V-0 rating). The peak heat release rate (pk-HRR) indicated that all LDHs containing REEs obviously reduced the fire strength in comparison with S-MgAl. In particular, pk-HRR of S-LaMgAl/APP/CFA/EVA, S-CeMgAl/APP/CFA/EVA and S-NdMgAl/APP/CFA/EVA were all decreased by more than 82% in comparison with pure EVA. Furthermore, the total heat release (THR), smoke production rate (SPR), and production rate of CO (COP) also decreased significantly. The average mass loss rate (AMLR) confirmed that the flame retardant exerted an effect in the condensed phase of the composites. Meanwhile, the combination of APP, CFA, and LDH containing REEs allowed the EVA matrix to maintain good mechanical properties.
High Temperature Pressure Oxidation of a Low-Grade Nickel Sulfide Concentrate with Control of the Residue Composition
Authors: McDonald Robbie G. , Li Jian , Austin Peter J.
Published: March 2020

High temperature pressure oxidation of a low-grade nickel concentrate was examined to demonstrate the potential benefits and shortcomings of this approach. The high iron sulfide content ensured that acid generation was much greater than for higher grade concentrates. This results in the formation of basic iron sulfate phases and a significant amount of sulfuric acid. Kinetic sampling during pressure oxidation tests also demonstrated the transformation of sulfide minerals, including the oxidative transformations of pentlandite to violarite and then to vaesite, the latter phase not previously noted in studies of this kind. Finally, addition of a divalent metal sulfate buffer, here magnesium sulfate, mitigates the formation of basic iron sulfates but with greater generation of sulfuric acid in the leach liquor. Under the conditions employed in this study, this acid could be employed to leach other nickel-containing materials such as nickel laterites.
The Paleoproterozoic Kandalaksha-Kolvitsa Gabbro-Anorthosite Complex (Fennoscandian Shield): New U–Pb, Sm–Nd, and Nd–Sr (ID-TIMS) Isotope Data on the Age of Formation, Metamorphism, and Geochemical Features of Zircon (LA-ICP-MS)
Authors: Steshenko Ekaterina N. , Bayanova Tamara B. , Serov Pavel A.
Published: March 2020

The paper provides new U–Pb, Sm–Nd, and Nd–Sr isotope-geochronological data on rocks of the Paleoproterozoic Kandalaksha-Kolvitsa gabbro-anorthosite complex. Rare earth element (REE) contents in zircons from basic rock varieties of the Kandalaksha-Kolvitsa area were analyzed in situ using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Plots of REE distribution were constructed, confirming the magmatic origin of zircon. Temperatures of zircon crystallization were estimated using a Ti-in-zircon geochronometer. The U–Pb method with a 205Pb artificial tracer was first applied to date single zircon grains (2448 ± 5 Ma) from metagabbro of the Kolvitsa massif. The U–Pb analysis of zircon from anorthosites of the Kandalaksha massif dated the early stage of the granulite metamorphism at 2230 ± 10 Ma. The Sm–Nd isotope age was estimated on metamorphic minerals (apatite, garnet, sulfides) and whole rock at 1985 ± 17 Ma (granulite metamorphism) for the Kolvitsa massif and at 1887 ± 37 Ma (high-temperature metasomatic transformations) and 1692 ± 71 Ma (regional fluid reworking) for the Kandalaksha massif. The Sm–Nd model age of metagabbro was 3.3 Ga with a negative value of εNd = 4.6, which corresponds with either processes of crustal contamination or primary enriched mantle reservoir of primary magmas.
General Strategy to Prepare Single-Layered Ag–Au–Pt Nanocrystal Ternary-Coated Biomass Textiles through Polymer-Driven Self-Assembly
Authors: Gao Liheng , Feng Jundan , Xu Sijun , Shi Min , Yao Lirong , Wang Lu , Yang Zhongtian
Published: March 2020

Current metal nanomaterials for developing nanofunctional textiles are mostly based on metal nanoparticles (NPs) that show aqueous instability, a tendency to aggregate, and low chemical affinity to biomass textiles, leading to low nano-metal uptake during finishing, significant declines in function, and nano-pollution. Herein, we demonstrate a strategy to transform metal (Ag, Au, and Pt) NPs into homogenous hyperbranched poly(amide-amine) (HBPAA)-encapsulated NPs showing high water solubility, oxidative resistance, and affinity to biomass materials upon surface capping with HBPAA. The proposed method represents a universal, simple, clean, and efficient self-assembly technology to produce monolayered Ag–Au–Pt ternary-coated biomass textiles. The combination of Ag, Au, and Pt NPs yields a positive potential of approximately +37.12 mV depending on the metal concentration and could simultaneously self-assemble onto natural fibers, including cotton, silk, and wool, through the one-step impregnation of textiles. Increasing the temperature and concentration of the mixture favors the self-assembly process. A mixture of 30–110 mg/L Ag, Au, and Pt NPs could nearly completely anchor onto cotton, silk, and wool textiles after impregnation at 100 °C for 1 h without chemical assistance, thereby indicating the possibility of clean production. As-prepared functional cotton, silk, and wool possessed similarly high antibacterial activities, and a mixture containing over 1500 mg/g NPs inhibited 99% of the Escherichia coli and Staphylococcus aureus in the sample textiles. The developed coating technology is simple, clean, controllable, and broadly applicable; thus, it could be potentially applied in functional textiles.
Polymeric Core-Shell Nanoparticles Prepared by Spontaneous Emulsification Solvent Evaporation and Functionalized by the Layer-by-Layer Method
Authors: Szczęch Marta , Szczepanowicz Krzysztof
Published: March 2020

The aim of our study was to develop a novel method for the preparation of polymeric core-shell nanoparticles loaded with various actives for biomedical applications. Poly(caprolactone) (PCL), poly(lactic acid) (PLA) and poly(lactide-co-glycolide) (PLGA) nanoparticles were prepared using the spontaneous emulsification solvent evaporation (SESE) method. The model active substance, Coumarin-6, was encapsulated into formed polymeric nanoparticles, then they were modified/functionalized by multilayer shells’ formation. Three types of multilayered shells were formed: two types of polyelectrolyte shell composed of biocompatible and biodegradable polyelectrolytes poly-L-lysine hydrobromide (PLL), fluorescently-labeled poly-L-lysine (PLL-ROD), poly-L-glutamic acid sodium salt (PGA) and pegylated-PGA (PGA-g-PEG), and hybrid shell composed of PLL, PGA, and SPIONs (superparamagnetic iron oxide nanoparticles) were used. Multilayer shells were constructed by the saturation technique of the layer-by-layer (LbL) method. Properties of our polymeric core-shell nanoparticle were optimized for bioimaging, passive and magnetic targeting.
Rodents as Hosts of Pathogens and Related Zoonotic Disease Risk
Authors: Dahmana Handi , Granjon Laurent , Diagne Christophe , Davoust Bernard , Fenollar Florence , Mediannikov Oleg
Published: March 2020

Rodents are known to be reservoir hosts for at least 60 zoonotic diseases and are known to play an important role in their transmission and spread in different ways. We sampled different rodent communities within and around human settlements in Northern Senegal, an area subjected to major environmental transformations associated with global changes. Herein, we conducted an epidemiological study on their bacterial communities. One hundred and seventy-one (171) invasive and native rodents were captured, 50 from outdoor trapping sites and 121 rodents from indoor habitats, consisting of five species. The DNA of thirteen pathogens was successfully screened on the rodents’ spleens. We found: 2.3% of spleens positive to Piroplasmida and amplified one which gave a potentially new species Candidatus “Theileria senegalensis”; 9.35% of Bartonella spp. and amplified 10, giving three genotypes; 3.5% of filariasis species; 18.12% of Anaplasmataceae species and amplified only 5, giving a new potential species Candidatus “Ehrlichia senegalensis”; 2.33% of Hepatozoon spp.; 3.5% of Kinetoplastidae spp.; and 15.2% of Borrelia spp. and amplified 8 belonging all to Borrelia crocidurae. Some of the species of pathogens carried by the rodents of our studied area may be unknown because most of those we have identified are new species. In one bacterial taxon, Anaplasma, a positive correlation between host body mass and infection was found. Overall, male and invasive rodents appeared less infected than female and native ones, respectively.
Principles of Drug Dosing in Sustained Low Efficiency Dialysis (SLED) and Review of Antimicrobial Dosing Literature
Authors: Brown Paula , Battistella Marisa
Published: March 2020

The use of sustained low-efficiency dialysis (SLED) as a renal replacement modality has increased in critically ill patients with both acute kidney injury (AKI) and hemodynamic instability. Unfortunately, there is a paucity of data regarding the appropriate dosing of medications for patients undergoing SLED. Dose adjustment in SLED often requires interpretation of pharmacodynamics and pharmacokinetic factors and extrapolation based on dosing recommendations from other modes of renal replacement therapy (RRT). This review summarizes published trials of antimicrobial dose adjustment in SLED and discusses pharmacokinetic considerations specific to medication dosing in SLED. Preliminary recommendation is provided on selection of appropriate dosing for medications where published literature is unavailable.
Fall Risk in Older Adults Transitioning between Different Flooring Materials
Authors: Kim Hyung Nam , Lockhart Thurmon E.
Published: March 2020

As there is lack of understanding about the effect of transitioning between different flooring materials on the gait of older adults, this study investigated the effect of transitioning between a carpeted floor and a vinyl floor on the gait characteristics of older adults. Fourteen older (65 years old and over) and 14 younger (18 to 35 years old) adults walked on different transitional floors by measuring various gait parameters. While the older participants had greater toe clearance than their younger counterparts, the older participants had smaller toe clearance on a carpeted floor than on a vinyl floor, which would increase the probability of a trip-induced fall. Further, the study found the slower transitional acceleration of the whole body COM and the increased friction demand, especially during the toe-off phase, rather than heel contact phase, which will lead to a slip-induced fall on a vinyl floor shortly after transitioning from a carpeted floor to a vinyl floor. Although the increased likelihood of a slip or trip accident was found throughout the changes in gait parameters, the older participants did not perceive of slipping and tripping much. Therefore, older adults are recommended to be made aware of the danger of slipping and tripping while transitioning between different flooring materials.
An E-Tailer’s Operational Strategy under Different Supply Chain Structures
Authors: Pi Shangyu , Wang Yang
Published: March 2020

Motivated by the enormous business success of E-tailers and their distinct business strategies, this paper analyzes the characteristics of dual online channel competition and the fundamental willingness of an E-tailer to open its marketplace to other retailers while at the same time competing with them. We build game theory models to study the dual-channel competition between an incumbent E-tailer and other online retailers under different supply chain structures. Either the manufacturer or authorized third-party retailers can start an online store in the E-tailer’s marketplace. The results show that the transaction fee charged by the platform and the service level provided to customers play significant roles in deciding the marketplace business strategy—the E-tailer faces complicated issues when these two factors fluctuate. A pure strategy of raising the transaction fee may not always be beneficial and a competitor’s superior service level may help to enhance a rival’s sales price. In the expanded research, dual online channel competition with an unauthorized third-party retailer, which is common in the online marketplace, is also examined.
From Colonial Research Spirit to Global Commitment: Bayer and African Sleeping Sickness in the Mirror of History
Authors: Madeja Ulrich-Dietmar , Schroeder Ulrike
Published: March 2020

In the early 20th century, a series of epidemics across equatorial Africa brought African sleeping sickness (human African trypanosomiasis, HAT) to the attention of the European colonial administrations. This disease presented an exciting challenge for microbiologists across Europe to study the disease, discover the pathogen and search for an effective treatment. In 1923, the first “remedy for tropical diseases”—Suramin—manufactured by Bayer AG came onto the market under the brand name “Germanin.” The development and life cycle of this product—which today is still the medicine of choice for Trypanosoma brucei (T.b), hodesiense infections—reflect medical progress as well as the successes and failures in fighting the disease in the context of historic political changes over the last 100 years.
High Levels of Treatment Success and Zero Relapse in Multidrug-Resistant Tuberculosis Patients Receiving a Levofloxacin-Based Shorter Treatment Regimen in Vietnam
Authors: Anh Le T. N. , M. V. Kumar Ajay , Ramaswamy Gomathi , Htun Thurain , Thanh Hoang Thi Thuy , Hoai Nguyen Giang , Quelapio Mamel , Gebhard Agnes , Nguyen Hoa Binh , Nguyen Nhung Viet
Published: March 2020

Vietnam has been using a levofloxacin-based shorter treatment regimen (STR) for rifampicin resistant/multidrug-resistant tuberculosis (RR/MDR-TB) patients since 2016 on a pilot basis. This regimen lasts for 9–11 months and is provided to RR/MDR-TB patients without second-line drug resistance. We report the treatment outcomes and factors associated with unsuccessful outcomes. We conducted a cohort study involving secondary analysis of data extracted from electronic patient records maintained by the national TB program (NTP). Of the 302 patients enrolled from April 2016 to June 2018, 259 (85.8%) patients were successfully treated (246 cured and 13 ‘treatment completed’). Unsuccessful outcomes included: treatment failure (16, 5.3%), loss to follow-up (14, 4.6%) and death (13, 4.3%). HIV-positive TB patients, those aged ≥65 years and patients culture-positive at baseline had a higher risk of unsuccessful outcomes. In a sub-group of patients enrolled in 2016 (n = 99) and assessed at 12 months after treatment completion, no cases of relapse were identified. These findings vindicate the decision of the Vietnam NTP to use a levofloxacin-based STR in RR/MDR-TB patients without second-line drug resistance. This regimen may be considered for nationwide scale-up after a detailed assessment of adverse drug events.
THEORETICAL-METHODOLOGICAL FOUNDATIONS OF RESEARCH ON THE PROBLEMS OF DEMOCRACY IN HISTORICALPHILOSOPHICAL DISCOURSE
Authors: Ryabeka Yevheniya
Published: March 2020

An analysis of the approaches to defining the content and basic parameters of democracy should obviously begin with Aristotle's eminent ancient thinker. Analyzing Aristotle's work, we come to the conclusion that democracy is based on the middle class and a free market economy. A new stage in the understanding of democracy has to do with the achievements of modern-day philosophers. J.-J. Rousseau writes in the paper “On the Social Treaty” that democracy is an instrument of ensuring the rights and freedoms of citizens and protecting minorities. Representatives of German classical philosophy made a fundamental contribution to the development of theories of democracy. In particular, in the writings of I. Kant we find the justification of the republican monarchy as a model of democracy in which the monarch obeys the will of the citizens. Ideally, these citizens should ideally be carriers of a disengaged mind, capable of philosophically formulating progressive ideas and demands for incumbent power. J. Fichte substantiated the approach according to which the people should take part in the state processes, and the authorities should ensure the implementation of the people's decisions: according to this approach, the will of the people is given a dominant importance, and the authorities are only trying to implement it. In Hegel's theoretical inheritance, an alternative view of democracy is upheld: the people are interpreted by the philosopher rather as a formless mass, and the fullness of power must belong to the monarch.