bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of the riverine nutrient export to the Tropical Atlantic over the last 15 years: is there a link with Sargassum proliferation?
Authors: Jouanno Julien , Moquet Jean-Sébastien , Berline Léo , Radenac Marie-Hélène , Santini William , Changeux Thomas , Thibaut Thierry , Podlejski Witold , Ménard Frédéric , Martinez Jean-Michel , Aumont Olivier , Sheinbaum Julio , Filizola Naziano , Moukandi N’Kaya Guy Dieudonne 
Published: January 2021

Abstract
The Tropical Atlantic is facing a massive proliferation of Sargassum since 2011, with severe environmental and socioeconomic impacts. As a contribution to this proliferation, an increase in nutrient inputs from the tropical rivers, in response to climate and land use changes or increasing urbanization, has been often suggested and widely reported in the scientific and public literature. Here we discuss whether changes in river nutrient inputs could contribute to Sargassum proliferation in the recent years or drive its seasonal cycle. Using long-term in situ and satellite measurements of discharge, dissolved and particulate nutrients of the three world largest rivers (Amazon, Orinoco, Congo), we do not find clear evidences that nutrient fluxes may have massively increased over the last 15 years. Moreover, focusing on year 2017, we estimate that along the year only 10% of the Sargassum biomass occurred in regions under river plume influence. While deforestation and pollution are a reality of great concern, our results corroborate recent findings that hydrological changes are not the first order drivers of Sargassum proliferation. Besides, satellite observations suggest that the major Atlantic river plumes suffered a decrease of phytoplankton biomass in the last two decades. Reconciling these observations requires a better understanding of the nutrient sources that sustain Sargassum and phytoplankton growth in the region.
The impact of non-breaking surface waves in upper-ocean temperature simulations of the Last Glacial Maximum
Authors: Wang Shizhu , Gong Xun , Qiao Fangli , Gowan Evan J , Streffing Jan , Lohmann Gerrit 
Published: January 2021

Abstract
Widespread mismatches between proxy-based and modelling studies of the Last Glacial Maximum (LGM) has limited better understanding about interglacial-glacial climate change. In this study, we incorporate non-breaking surface waves (NBW) induced mixing into an ocean model to assess the potential role of waves in changing a simulation of LGM upper oceans. Our results show a substantial 40 m subsurface warming introduced by surface waves in LGM summer, with larger magnitudes relative to the present-day ocean. At the ocean surface, according to the comparison between the proxy data and our simulations, the incorporation of the surface wave process into models can potentially decrease the model-data discrepancy for the LGM ocean. Therefore, our findings suggest that the inclusion of NBW is helpful in simulating glacial oceans.
Effect of multiple forging and annealing on microstructure and mechanical properties of a high-manganese steel
Authors: Dolzhenko P D , Valiev R Z , Belyakov A N , Bobruk E V , Tikhonova M S 
Published: January 2021

Abstract
The effect of multiple forging and annealing on the microstructure and mechanical properties of a high-manganese steel is considered. An austenitic high-manganese steel, Fe-0.03C-28Mn-1.5Al (all in wt.%), with an average grain size of about 37 μm was used as the initial material in this study. Multiple forging at room temperature was carried out up to a total true strain of 2. Multiple forging was accompanied by deformation twinning and resulted in significant strengthening. The steel samples subjected to multiple forging demonstrate an increase in the strength properties with an increase in the total strain, while elongation decreases. After multiple forging to a total strain of 2, the samples were annealed at temperatures from 673 to 1073 K for 30 minutes. An increase in the annealing temperature leads to a decrease in the strength and a significant increase in plasticity. Annealing at temperatures of T ≥ 873 K leads to the formation of a recrystallized microstructure.
Prediction of the strength of high entropy alloys of the Al-Cr-Nb-Ti-V-Zr system by the solid-solution hardening model
Authors: Klimenko D N , Stepanov N D , Zherebtsov S V 
Published: January 2021

Abstract
An approach based on the phase prediction of both the phase composition and the solid solution hardening was investigated. This approach showed good agreement between the calculated and experimental values of the yield strength at 20 and 600 °C.
Investigation of the impulse impact effect in the process of additive manufacturing of metal products by plasma cladding
Authors: Neulybin S D , Shchitsyn Yu D , Permyakov G L , Belinin D S , Varushkin S V 
Published: January 2021

Abstract
Additive technologies (AT) or layered synthesis technologies are one of the most dynamically developing areas of “digital” production. A common problem of additive technologies is ensuring the proper microstructure of the synthesized material and the eliminating defects. The use of filler wire as a working material eliminates the problems associated with the low productivity of existing methods, the high cost of the equipment used, the limited types of materials used, due to the use of powder systems. Products made of stainless chromium-nickel steels are widely used in various industries. The main problem of additive technologies is to ensure the properties of the laminates are not lower than those obtained by traditional methods. Characteristic defects of laminated materials obtained by surfacing are increased porosity, non-metallic inclusions, a decrease in ductility, and for high-alloy steels, a loss of special properties. This predetermined the development of research in the field of additional technological measures to improve the final properties of the product. This paper presents the results of a study of the effect of ultrasonic vibrations on the structure and properties of the deposited steel 12Cr18Ni10Ti. For welding was used the wire 12Cr18Ni10Ti, process was carried out by plasma arc in a protective argon gas. It was found that ultrasonic treatment has an effect on the final grain size, structure formation and hardness, as well as on the geometry of the deposited layer. Studies show that the use of ultrasonic vibrations in the process of surfacing can be applied in the design of equipment for the implementation of processes of additive production.
Influence of nitriding parameters in radio-frequency inductive discharge plasma on the structural-phase state and properties of H12MF steel
Authors: Novikov V Y , Goncharov I Y , Yapryntsev M N , Gazizova M Y 
Published: January 2021

Abstract
The influence of technological parameters of plasma nitriding on the structural-phase state and mechanical properties of H12MF steel has been investigated in this work. The possibility of improving the corrosion resistance of the reported material was demonstrated by changing the content of nitride phases (Fe3N, Fe4N, CrN) in the surface layer, depending on the nitriding mode.
Synthesis and magnetic properties of solid solutions of a diluted magnetic semiconductor (Zn1-xFex)3As2
Authors: Zakhvalinskii V S , Nikulicheva T B , Pilyuk E A , Trubaev A A , Usatyy I M 
Published: January 2021

Abstract
The magnetic properties of the new semimagnetic semiconductor (Zn1-xFex)3As2 with x < 0.04 have been investigated over a wide temperature range. Single crystals of ZFA were grown using the modified Bridgeman technique. The results of X-ray analyses and the magnetometry data show that the border of solid solutions in this system lay near x = 0.015. Further increasing of x leads to the growing of the second phase, which was identified as Fe2As. A notable feature of our magnetometry results is the spin-glass-type freezing of magnetic moments in the temperature range of 10 - 50 K. The value of the freezing temperature decreases when the magnetic field increases and in 2 kOe magnetic field the effect is no longer observable. It is likely that the observed freezing phenomena are due to the cluster nature of magnetic properties of ZFA. The thermoremanent magnetization measurements give evidence for two types of clusters in the magnetic system of ZFA.
Influence of titanium and chrome on the structure and heat resistance of layered composites from a multicomponent Nb-alloy and intermetallic compounds of aluminium
Authors: Prokhorov D V , Korzhov V P 
Published: January 2021

Abstract
Investigations of the structure and measurements of the strength characteristics of layered composites of niobium alloys prepared by diffusion welding under pressure have been carried out. It was found that titanium has a strong effect on the formation of microstructure and strength of composites. Higher values of short-term strength and fracture toughness are demonstrated by layered composites with a lower titanium content.
Investigation of the formation and distribution of elements in the production of Al-Ti-V-Zr-Nb alloys by the aluminothermic method
Authors: Russkih A S , Krasikov S A , Zhilina E M , Zhidovinova S V 
Published: January 2021

Abstract
The results of testing the method for synthesis of a high-entropy AlNbTiVZr alloy using metallothermic reduction of group IV and V metals from their oxides are presented. At the first stage, a joint aluminothermic recovery of metals in a resistance furnace was performed. Then, to achieve uniformity and remove harmful impurities, the metal was melted in a vacuum furnace with an inert atmosphere. The alloy obtained after the second remelting was subjected to x-ray diffraction and electron microprobe (EMA) analysis. The results of the analysis revealed the presence of a solid solution of Zr (Nb, V) with TiAl inclusions, which confirms the prospects of using metallothermic synthesis to produce a high-entropy alloy with a single-phase structure.
New high-entropy oxide phases with the perovskite structure
Authors: Zaitseva O V , Gudkova S A , Trofimov E A , Zhivulin V E , Punda A Yu , Starikov A Yu , Vinnik D A 
Published: January 2021

Abstract
Results of studying the structure and chemical composition of perovskite phases synthesized by solid-state sintering in multicomponent oxide systems: (Ba,Sr,Ca,Mg,Pb)(Ti,Zr)O3, (Ba,Sr,Ca,Mg,Pb)(Ti,Zr,Hf)O3, (Ba, Sr, Ca,Mg,Pb)(Ti,Zr,Hf, Sn)O3, and (Ba,Sr,Ca,Mg,Pb)(Ti,Zr,Hf,Sn,Mn)O3 are presented. The chemical composition of the obtained samples was investigated using a JEOL JSM7001F scanning electron microscope equipped with an Oxford INCA X-max 80 energy-dispersive X-ray fluorescence spectrometer. The structure was studied with a Rigaku Ultima IV powder X-ray diffractometer. It was demonstrated the possibility of obtaining a high-entropy perovskite phase. Elements (Ba, Sr, Ca, Ti, Zr, Hf, Sn), which can form the high-entropy perovskites have been determined, as well as the elements (Pb, Mg, Mn), which, for various reasons, are hardly incorporated in the high-entropy perovskites.
Process Improvement Using Six-Sigma (DMAIC Process) in Bearing Manufacturing Industry: A Case Study
Authors: Bhargava Manish , Gaur Sanjay 
Published: January 2021

Abstract
Propagation, development of technologies and increasing customer demands switch the approach of existing work in the industries. To overcome barricades, the six-sigma DMAIC (define, measure, analyse, improvement, control) approach is trendy along with being advantageous. This approach decreases the variation and set up the way for up gradation in the manufacturing companies. This paper contains the Six-Sigma DMAIC approach that was used to decrease the process variation of inner and outer races of ball bearing for enhancing product quality. Define phase of DMAIC approach begins by difficulty detection through the voice of internal and external customers. The later stage constitute of measuring the data of bearing parts of existing process. This stage followed by the analyze as well as improvement stage, where the Six-Sigma quality improvement tools i.e. statistical process control (SPC), Control charts, MINITAB 18.0 software, fish bone diagram along with significant study of alive process were imposed to identify root causes and minimizing process variability. The improvement stage minimized the assignable causes for variability. The control phase called to maintain the improved process till further improvement.
This work expected that the Six-Sigma DMAIC methodology was effective for increasing the sigma level, decreasing the value of standard deviation and also decreasing the expected part per million (PPM) out of specification limits. Values of capability indices i.e. (Cp, Cpk and Cpm) were improved. A Six-Sigma DMAIC methodology is well-known and is capable of playing an efficient role in manufacturing industry by reducing variability in the bearing part process.
Tolerance analysis of a GFET transistor for aerospace and aeronautical application
Authors: Lamberti P , Mura M La , Pasadas F , Jiménez D , Tucci V 
Published: January 2021

Abstract
Due to the high carrier mobility, graphene is considered a promising material for use in high-speed electronic devices in the post-silicon electronic era. Graphene high resistance to radiation and extreme temperatures makes the development of graphene-based electronics a key-enabling technology for aerospace, defence, and aeronautical applications. Nevertheless, achieving uniform device-to-device performance is still a challenge, and these fields require high reliability components. In particular, many critical issues remain to be solved, such as their reproducibility and guaranty of identical performances against possible variations of different manufacturing and environmental factors. In the present work, a model capable to take into account the physical characteristics linked to the production process of a Graphene Field-Effect Transistor (GFET) is exploited to carry out a tolerance analysis of process-related geometrical parameters on the device performance. The most influential parameters that affect the device behaviour are studied in order to enhance the fabrication yield.
Application of different Lagrangian Particle Tracking techniques for water impingement
Authors: Petrosino F. , De Rosa D. , Mingione G. 
Published: January 2021

Abstract
Water impingement on aerodynamic surfaces represents how much flow rate water mass impact on the surfaces, respect to total mass flow rate. This parameter, together with Liquid Water Content, is important in ice prediction since it defines water mass distribution on solid surface, by which depends several other problems like freezing fraction, anti-icing system, etc. In this work we focus on the lagrangian method to calculate droplets’ trajectory, comparing the results against 2D and 3D experimental data.
Design of a composite nose wheel for commercial aircraft
Authors: Wacker J-D , Laveuve D , Contell Asins C , Büter A 
Published: January 2021

Abstract
Innovative approaches for lightweight design of components can contribute significantly to reduced fuel consumption and emissions of future aircraft. Within the framework of the European aviation research program Clean Sky 2, an innovative design of an aircraft nose wheel for the A320 is developed using carbon fiber reinforced plastics (CFRP) in order to demonstrate a weight reduction potential of 27% compared to conventional designs. In the present paper, the approach of the development process and the final detailed design of the composite aircraft wheel as well as a manufacturing concept are presented, various design challenges are highlighted and the solutions developed to meet them are discussed. Within a concept phase different structural design principles for the wheel are analyzed, taking into account the challenging load cases during different phases of aircraft operation. The selected innovative design principle is further elaborated into a detailed design considering design challenges such as space, installation, and safety requirements, as well as integration of bearings, seals and joint solutions. Also, structural analysis of the composite components via FEA and experimental validation of the joints are discussed. In addition, the manufacturing concept for the complex wheel geometry via resin transfer molding (RTM) using carbon non-crimp fabrics is presented and an outlook on the future manufacturing and testing of wheel prototypes is given.
Robot deployed Laser-Ultrasonic NDT system for inspection of large aircraft structures
Authors: James Vicki , Carswell Dave , Riise J , Nicholson P. Ian , Graf Norbert , Huber Norbert , Gärtner Martin , Reitinger Bernhard , Scherleitner Edgar , Burgholzer Peter , Phipps Jon , Burns Dave , Incarnato Ciro 
Published: January 2021

Abstract
The mandatory Non-Destructive Testing (NDT) by the aerospace industry for both present and future generation hybrid aircraft using thick composite structures poses many challenges for traditional inspection techniques. Laser Ultrasonic Testing (LUT) deployed by a robot for inspection of modern aerospace composite components shows good promise. It is a non-contact method offering the possibility of fast scan times without the need for couplant. This paper presents the latest work-in-progress for the design and development of the system developed by the ACCURATe consortium. ACCURATe is an ongoing H2020 Clean Sky 2 part funded project to develop a laser ultrasound based NDT system prototype for fast and contactless testing of large carbon fibre reinforced polymer (CFRP) aircraft structures.
The approach is based on a non-contact laser generated and detected pulsed ultrasound technique with delivery of both the laser ultrasound excitation and detection pulses through flexible optical fibres. The backscattered light from the lasers is also collected into a fibre. The measurement head, which contains the two beam outputs and the light collection optics is raster scanned over the surface by a 6-axis robot arm. A balanced two wave mixing interferometer (B-TWM) is used for the demodulation of the ultrasonic waves.
The system has recently been used to scan a reference panel, and a scrap panel of fuselage, the latest test results are presented and show promising progress against the project objectives.
Aerial Stability Of An In-Flight Water Scooping System
Authors: Verhagen Mario , Timmermans Huub , den Brink Wouter van 
Published: January 2021

Abstract
Given operational restrictions of current firefighting aircraft, a novel concept is proposed within SCODEV. Launched within the Horizon 2020 Fast Track to Innovation framework, SCODEV considers a novel system that refills an aircraft’s water tanks during low altitude flight. The novel scooping system consists of a hose and a scoop that penetrate the water surface during low altitude flight. Though promising major benefits with respect to current firefighting aircraft, the design of such a novel scooping system poses significant and unique challenges. For safe and successful water scooping, it is paramount that the scooping system, consisting of the hose and scoop, maintains a stable shape when being lowered and at any extended position, that the hose maintains a desired shape with a sufficiently vertical attitude, and that the scoop maintains a desired attitude with respect to the airflow, before entering the water. Focusing on system prerequisites that allow for initiation of water ingestion, this paper does not consider system response during water ingestion, reel-in or fly-out. The hose and scoop are designed and assessed through simulations, taking into account the three aforementioned criteria. The scoop and hose are designed and assessed separately in the simulation environment. For the hose, quasi-dynamic aeroelastic analyses are performed by coupling the structural Abaqus solver with an external aerodynamic code and iterating for a hose shape in space. It is assessed whether the hose can maintain a stable shape while being lowered, and at full length. Secondly, it is assessed whether the hose can maintain a desired shape at full length, maintaining a sufficiently vertical attitude. For the scoop, aerial stability analyses have been performed using MSC Nastran. The scoop is designed to maintain a stable and desired orientation with respect to the oncoming airflow. Helicopter flight tests are performed to substantiate analytical results on hose and scoop stability, hose shape and scoop orientation. When the scoop and hose are tested separately, observed behaviour is in good agreement with simulation predictions; the hose remains stable and has a desired shape with sufficiently vertical attitude. The scoop similarly remains stable and maintains a desired orientation with respect to the incoming airflow. For the coupled system, system behaviour differs from analytical predictions. This highlights the need to consider the coupled system in the simulations instead of analysing both components separately.
2D optimization of a Small Horizontal Axis Wind Turbine blade using flow control techniques
Authors: Papadopoulos C , Kaparos P , Vlahostergios Z , Misirlis D , Yakinthos K 
Published: January 2021

Abstract
In this work, the optimization of the efficiency of a small horizontal axis wind turbine (SHWT) blade segment is presented. Typically, SHWTs have a radius of 1.5 to 3.5 m and a hub height of around 15 m from the ground. SHWTs operate in a relatively small Reynolds numbers range (up to 1.5x106) and are installed inside the atmospheric boundary layer. This operational environment is characterised by volatile air flow, making the flow over the blade prone to separation. In order to counter this flow behavior, a set of flow control techniques is introduced and studied. These techniques control the flow, either passively, solely by the inclusion of blade add-ons, or actively, by adding energy to the boundary layer. More specifically, two passive flow control techniques and one active flow control technique are modelled and tested on a wind turbine blade segment. The passive techniques implemented in this study are based on the use of vortex generators and tubercles. Vortex generators are small vanes attached vertically to the lifting surface and are widely used in aerospace applications with varying degrees of success. Tubercles, which is a novel flow control technique, are sinusoidal modifications of the blade’s leading edge. The original concept has been inspired from the characteristic flipper of the humpback whale (Megaptera Novaeangliae). Regarding the active flow control technique, a dielectric barrier discharge (DBD) plasma actuator (PA) is used, a technique that adds momentum on the local flow, close to the blade’s surface, by ionizing the air. The impact on the blade aerodynamic efficiency for each technique are evaluated and presented. The results from this evaluation show that flow control techniques can offer a considerable benefit to SHWT by improving the blade’s aerodynamic characteristics, i.e. by increasing the blade lift-to-drag ratio and thus, improving their critical performance efficiency factor.