bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation
Authors: Edelmann P. V. F. , Ratnasingam R. P. , Pedersen M. G. , Bowman D. M. , Prat V. , Rogers T. M.
Published: April 2019

We present the first three-dimensional (3D), hydrodynamic simulations of the core convection zone (CZ) and extended radiative zone spanning from 1% to 90% of the stellar radius of an intermediate-mass (

) star. This allows us to self-consistently follow the generation of internal gravity waves (IGWs) at the convective boundary and their propagation to the surface. We find that convection in the core is dominated by plumes. The frequency spectrum in the CZ and that of IGW generation is a double power law, as seen in previous two-dimensional (2D) simulations. The spectrum is significantly flatter than theoretical predictions using excitation through Reynolds stresses induced by convective eddies alone. It is compatible with excitation through plume penetration. An empirically determined distribution of plume frequencies generally matches the one necessary to explain a large part of the observed spectrum. We observe waves propagating in the radiation zone and excited standing modes, which can be identified as gravity and fundamental modes. They show similar frequencies and node patterns to those predicted by the stellar oscillation code GYRE. The continuous part of the spectrum fulfills the IGW dispersion relation. A spectrum of tangential velocity and temperature fluctuations close to the surface is extracted, which is directly related to observable brightness variations in stars. Unlike 2D simulations, we do not see the high frequencies associated with wave breaking, likely because the 3D simulations presented in this paper are more heavily damped.
Detectable Molecular Features above Hydrocarbon Haze via Transmission Spectroscopy with JWST: Case Studies of GJ 1214b-, GJ 436b-, HD 97658b-, and Kepler-51b-like Planets
Authors: Kawashima Yui , Hu Renyu , Ikoma Masahiro
Published: April 2019

Some of the exoplanets observed thus far show featureless or flat transmission spectra, possibly indicating the existence of clouds and/or haze in their atmospheres. Thanks to its large aperture size and broad wavelength coverage, the James Webb Space Telescope (JWST) is expected to enable a detailed investigation of exoplanet atmospheres, which could provide important constraints on the atmospheric composition obscured by clouds/haze. Here, we use four warm (≲1000 K) planets suitable for atmospheric characterization via transmission spectroscopy, GJ 1214b, GJ 436b, HD 97658b, and Kepler-51b, as examples to explore molecular absorption features detectable by JWST even in the existence of hydrocarbon haze in the atmospheres. We simulate photochemistry, the growth of hydrocarbon haze particles, and transmission spectra for the atmospheres of these four planets. We find that among the planetary parameters considered, super-Earths with hazy, relatively hydrogen-rich atmospheres are mostly expected to produce detectable molecular absorption features such as a quite prominent CH4 feature at 3.3 μm, even for the extreme case of the most efficient production of photochemical haze. For a planet that has extremely low gravity, such as Kepler-51b, haze particles grow significantly large in the upper atmosphere due to the small sedimentation velocity, resulting in the featureless or flat transmission spectrum in a wide wavelength range. This investigation shows that, in most cases, the transmission spectra with muted features measured by Hubble Space Telescope do not preclude strong features at the longer wavelengths accessible by JWST.
Teenagers, smartphones and digital audio consumption in the age of Spotify
Authors: Pedrero-Esteban Luis Miguel , Barrios-Rubio Andrés , Medina-Ávila Virginia
Published: April 2019

The consolidation of smartphones as dominant devices for access to digital information and entertainment has redefined the processes of production and commercialization of cultural communication industries. The nature of these screens, which prioritize the visual content over the sound, decisively influences distribution strategies in the audio market: radio operators, streaming music platforms and podcast creators need to adapt their value chains to the habits derived from this mediation, especially in the younger audience. This research identifies the practices of mobile use as an audio receiver among adolescents in Colombia, Spain and Mexico –the most representative countries of Spanish-speaking digital sound consumption– based on a descriptive study on a thousand subjects from 13 to 19 years of age. The results confirm the overwhelming dominance in this music menu in the face of low penetration of radio and podcast word content. The selection is based on personal criteria, with little margin for the prescription of family or friends. There is evidence of the roots of individual listening, linked to the brand and the visibility of audio providers, who are obliged to develop diffusion logics based not only on thematic or genre preferences, but also on the user experience.

La consolidación de los smartphones como dispositivos dominantes de acceso a la información y el ocio digital ha redefinido los procesos de producción y comercialización de las industrias culturales de la comunicación. La naturaleza de estas pantallas, que priorizan el contenido visual sobre el sonoro, determina hoy las estrategias de distribución y comercialización en el mercado del audio: operadores de radio, servicios de música en streaming y creadores de podcasts necesitan adecuar sus cadenas de valor a los hábitos derivados de esta mediatización, sobre todo en la audiencia más joven. Esta investigación identifica las prácticas de uso del móvil como receptor de audio entre los adolescentes de Colombia, España y México –los países más representativos del consumo digital sonoro hispanohablante– a partir de un estudio descriptivo sobre 1.004 sujetos de 13 a 19 años. Los resultados revelan el abrumador dominio de la música en este menú frente a la baja aceptación de los contenidos de palabra de radio y podcast. Su selección se asienta sobre criterios personales, con poco margen para la prescripción de familiares o amigos. Se constata el arraigo de una escucha individual, ligada a la marca y la visibilidad de los oferentes de audio, obligados a desarrollar lógicas de difusión basadas no sólo en preferencias de temas o géneros, sino también en las asociadas a la experiencia de usuario en estos terminales.
Systematic Review of Continuing Education Interventions for Licensed Nurses Working in Psychiatry
Authors: Hartley Heather , Smith Jenna Donn , Vandyk Amanda
Published: April 2019

Continuing education is an important part of nursing practice. These interventions help maintain clinical competence and are mandated by regulatory bodies. Often, continuing education interventions are created ad hoc and implemented without testing or formal evaluation of learning outcomes. In the current health care context, where resources are limited, educators are pressed to do more with less. Having access to a repository of existing continuing education interventions will facilitate the use of evidence-informed learning strategies and save valuable time by reducing duplication of efforts. Therefore, this systematic review aimed to explore continuing education interventions for licensed nurses working in psychiatry. All standard systematic review procedures were followed, including double screening, data extraction, and quality appraisal. This article presents an inventory of existing interventions, including summaries, as well as the reported effectiveness of each for nursing outcomes. Generally, the continuing education interventions result in positive nurse-related outcomes, such as increased knowledge, confidence, and skills, or improved attitudes; however, more rigorous research is needed to advance science in this area.

[
J Contin Educ Nurs.
2019;50(5):233–240.]
Adaptive E-Learning as a Possible Solution to Counter Heterogeneity in Classrooms? English Grammar Seen Through Cognitive Psychology and Psychometric Methods
Authors: Villessèche Julie , Oriez Sandrine , Besnard Anne-Laure , Le Bohec Olivier , Quaireau Christophe , Noël Yvonnick , De La Haye Fanny , Nogues Jérémie , Lavandier Karine
Published: April 2019

One of the main difficulties met in teaching Languages for Specialists of Other Disciplines (Lansod) is the heterogeneity of the learners’ levels. Handling a classroom is thus a challenge for teachers. In English, the improvement of both expression and comprehension competences, both written and spoken, depends on the knowledge of grammar, as shown by Ellis’s research (Second Language Acquisition). The project presented in this text (TACIT-Grammar) is part of the dynamic created in the universities in order to develop the use of digital technologies. The platform Tacit targets the evaluation and adaptive remediation of cross-disciplinary cognitive and linguistic competences. In this context, a module dedicated to English grammar is currently in progress to meet the specific needs of the Lansod.
Quel français enseigner dans les licences professionnelles au Maroc ?
Authors: Bouibhirne Souhail
Published: April 2019

Depuis leur création en 2005, les licences professionnelles attirent de plus en plus d’étudiants à l’université. Cet engouement est expliqué par les exigences du marché de l’emploi. Néanmoins, l’accès à ces filières professionnelles ne se fait pas sans difficultés ; d’une part les étudiants doivent passer par une présélection sur dossier et d’autre part ils sont censés suivre des cours de spécialité dans une langue étrangère, en l’occurrence le français. Cette dernière difficulté est ressentie par la majorité des étudiants car la langue d’enseignement passe de l’arabe standard au cycle secondaire qualifiant à la langue française au cycle supérieur (pour les filières scientifiques et techniques). Plusieurs mesures ont été effectuées afin de remédier à cette « fracture linguistique », entre autres la création d’un module appelé « langue et terminologie » qui vise essentiellement une remise à niveau linguistique. Or, les profils des étudiants sont très hétéroclites car ils sont issus de différentes filières au baccalauréat (économie, sciences expérimentales, sciences mathématiques etc.) et leur niveau de maitrise de la langue française est loin d’être identique. C’est dans cette perspective que s’inscrit cette contribution qui s’interroge sur la relation entre le cours de français d’une part et les besoins réels de ces étudiants d’autre part. Cette enquête sur terrain nous a permis de constater que l’enseignement d’un français général est loin de répondre à leurs besoins, à la différence d’un français sur objectifs universitaires qui s’avère le mieux adapté à leurs besoins aussi bien langagiers que méthodologiques.
High Energy Milling of WС-FeСr Cemented Carbide
Authors: Tarraste Marek , Kübarsepp Jakob , Juhani Kristjan , Kolnes Märt , Viljus Mart
Published: April 2019

During production of cemented carbides hard and brittle tungsten carbide (WC) and ductile metal powders (mainly from Fe-group) are milled together. Complete milling results in a Gaussian distribution and narrow particle size range of the milled powder which promote the homogeneity and improve the properties of sintered composites. Cobalt, conventional metal employed in cemented carbides, possesses good comminution characteristics with WC powder. However, its toxicity and fluctuating price pushes researchers to find suitable alternatives and Fe-based alloys have shown most promising results. Cemented carbides with the Fe-Cr system as metal binder phase have potential to perform better than regular WC-Co composites in corrosive and oxidative environments. The goal of this paper was to prepare uniform cemented carbides powders with relatively high fraction of stainless Fe-Cr steel. To achieve a uniform powder mixture is a challenge at high ductile steel fraction. High energy milling (HEM) is a powerful technique for achieving (ultra) fine powder mixtures with narrow powder size range. HEM was carried out in a novel high energy ball mill RETSCH Emax. Milling in tumbling ball mill, which is the most widely used method, was employed for reference. Prepared powder mixtures were characterised in terms of particle size, size distribution and shape. In addition, powder mixtures were consolidated via spark plasma sintering to evaluate the effect of the milling method and the duration on the microstructure of final cemented carbide.
Study of Devulcanised Crumb Rubber-Peat Bio-Based Composite for Environmental Applications
Authors: Lapkovskis Vjaceslavs , Mironovs Viktors , Irtiseva Kristine , Goljandin Dmitri
Published: April 2019

A proper recycling and secondary reuse of end-of-life car tires (ELTs) remain an important issue for many regions. Devulcanised crumb rubber as a product of ELT recycling could be used for very different applications, including site remediation by spilled oil products. In current paper a development of new bio-based composite material containing devulcanised crumb rubber and cenospheres is suggested. Designed bio-based composite can be used as a oil spill adsorbent, material for civil engineering, and as a raw material for further modification by introduction of ferromagnetic components. Homogenised peat with peat content 14.0 ± 1.5 wt%, particle size 0.01 – 0.5 mm used as a natural bio-based binder. Devulcanised crumb rubber particle size 1.0 – 4.0 mm was used as a porous substrate. Designed compositions contained 5, 10, 15, 20 wt% (before drying) of devulcanised crumb rubber. Cenospheres have duplex function for designed composite: lightweight additive that makes final product floatable, and at the same time minimises shrinkage of dried product. It was found that devulcanised crumb rubber reduces density of final composite and adding open porosity. Developed bio-based composites could be manufactured in granules by drum granulation technique for further environmental applications. Formability and apparent density of bio-based composite are studied.
Natural Climatic Aging of Epoxy Polymers Taking into Account the Seasonality Impact
Authors: Nizin Dmitrii R. , Nizina T.A. , Selyaev V.P. , Chernov A.N. , Gorenkova A.I.
Published: April 2019

The change in the elastic-strength and sorption properties of epoxy polymers in the process of natural aging, taking into account the sequence of different climatic seasons effects, was studied. We studied polymers obtained on the basis of low-viscosity epoxy resins and a hardener, which is a mixture of aromatic and aliphatic di-and polyamines, modified by salicylic acid. Differences in the processes of structural relaxation and elimination of the initial nonequilibrium depending on the season of the exposure start are revealed. Mathematical models that describe changes in the elastic-strength properties of epoxy polymers during climatic aging, depending on the accumulated quantitative values ​​of the acting environmental factors, have been developed. For the first time, it was proposed to use as a variable parameter the total duration of time intervals for the studied period the surface temperature of the samples at which exceeded the glass transition temperature.
Enhancement of Hydrogen Storage in Metals by Using a New Technique in Severe Plastic Deformations
Authors: Shahreza Babak Omranpour , Kommel Lembit , Sanchez E. Garcia , Ivanisenko Yulia , Huot Jacques
Published: April 2019

Hydrogen is expected to be a viable solution for green-energy investment in future. However, hydrogen storage is a big challenge for stationary and mobile applications. Severe Plastic Deformation (SPD) techniques are well-known to be effective in enhancement of hydrogenation in metals hydrides. This paper shows the effect of a novel SPD technique named “High Pressure Torsion Extrusion-HPTE” on the hydrogenation of metal hydrides and compare it with the conventional method of ECAP. Results of mechanical testing and X-ray diffraction patterns showed significant enhancement in hardness and microstructural refinement in materials after HPTE. Accordingly, hydrogenation kinetics improved dramatically. This achievement could be an initiative to implement HPTE in synthesis of metal hydrides for clean energy applications.
Characteristics and Photocatalytic Activity of Sm Doped ZnO Nanoparticles
Authors: Rodionovs Pavels , Jankovica Dzidra , Grabis Jānis
Published: April 2019

Sm2O3/ZnO nanoparticles were prepared via microwave-assisted hydrothermal and sol-gel combustion synthesis. Characteristics of obtained samples were compared in dependence of Sm2O3 content and calcination temperature. Prepared nanostructures were characterized with scanning electron microscopy and X-ray diffraction. Nanoparticles prepared via microwave-assisted hydrothermal and sol-gel method have flower-like and spherical shape respectively. The photocatalytic activity of samples under solar light simulated illumination was found to be affected by content of Sm2O3, calcination temperature and preparation method. The first-order rate constant of MB solution degradation of samples prepared via microwave-assisted hydrothermal method approximately three times exceeds that of sol-gel samples.
Electrochemical Treatment of Graphene
Authors: Usikov Alexander , Puzyk Mikhail V. , Novikov Sergey , Barash Iosif , Medvedev Oleg , Roenkov Alexander , Goryachkin Andrey , Lebedev Sergey P. , Zubov Alexander V. , Makarov Yuri , Lebedev Alexander A.
Published: April 2019

Treatment of graphene/SiC dies in inorganic electrolytes (KOH, KCl and Na2SO4) is discussed. An electrochemical method based on the cyclic voltammetry in a conventional three-electrode cell with Ag/AgCl reference electrode, a platinum counter electrode, and the graphene/SiC dies as working electrode (anode) is used for the treatment. It was observed either partial oxidation of graphene or its complete dissolution with the formation of CO2. The treatment performed resulted in the deterioration of the graphene films and change of the graphene-die resistivity depending on the range of the scanning potential applied to the graphene/SiC dies.
Average Residual Stresses in Hard Physical Vapor Deposited (PVD) Coatings
Authors: Lille Harri , Ryabchikov Alexander , Kõo Jakub , Mikli Valdek , Adoberg Eron , Vagiström Heinar , Kübarsepp Jakob , Peetsalu Priidu
Published: April 2019

In this study we determined average residual stresses in hard nitride PVD AlCrN, TiAlN and TiCN coatings through simultaneous measurement of length variation in thin-walled tubular substrates and of the curvature of plate substrates. A device for measurement of the length of the tube was developed. Inside the depositing chamber the tube and the plate were fixed parallel in the relation to the axis of the rotating cathode. One batch of plate samples was produced by deposition on front surface (facing the cathode) and the other batch, by deposition on back surface (with back to the cathode). The cross-sectional microstructure and thickness of the coatings were investigated by means of scanning electron microscopy (SEM). The thicknesses of the coatings deposited on front and back surfaces of the plates and on the tube were significantly different. The values of average compressive residual stresses, determined by both methods, were very high irrespective of coating thickness. It was found that the values of compressive residual stresses in the coating were dependent on the shape of the substrate and on its position in the relation to the axis of the rotating cathode.
Dynamic Analysis of a Viscoelastic Nanobeam
Authors: Arda Mustafa , Aydogdu Metin
Published: April 2019

Vibration of an axially loaded viscoelastic nanobeam is analyzed in this study. Viscoelasticity of the nanobeam is modeled as a Kelvin-Voigt material. Equation of motion and boundary conditions for viscoelastic nanobeam are provided with help of Eringen’s Nonlocal Elasticity Theory. Initial conditions are used in solution of governing equation of motion. Damping effect of the viscoelastic nanobeam structure is investigated. Nonlocal effect on natural frequency and damping of nanobeam and critical buckling load is obtained.
Use of Selective Laser Melting for Manufacturing the Porous Stack of a Thermoacoustic Engine
Authors: Auriemma Fabio , Holovenko Yaroslav
Published: April 2019

In this study the authors investigate the possibility of using Selective Laser Melting (SLM) to manufacture the porous element (stack) of a thermoacoustic engine. Two stacks, provided with different internal geometries but with the same hydraulic radii, have been produced: one with parallel plates and one with a new, oblique pin array configuration. The pin array stacks provide smaller amount of viscous losses during the thermal to acoustic power conversion when working fluids with Pr < 1, e.g. air. Furthermore, the oblique configuration is designed to reduce the heat transmission from the hot to the cold surface of the stack, thus to achieve more easily the temperature gradient for the onset of the thermoacoustic phenomenon. In general, the pin array configurations are difficult to manufacture with conventional technologies. However, the SLM provides precise control of the features of the printed object, thus allowing to objectively compare the behavior of the two stacks. To this aim, the temperature gradient between the hot and cold faces of the stacks and the corresponding sound pressure levels measured at 15 cm from the open end of the engine are measured and compared.
Selective Laser Melting of Ti/cBN Composite
Authors: Minasyan Tatevik , Liu Le , Aydinyan Sofiya , Antonov Maksim , Hussainova Irina
Published: April 2019

Titanium has been evaluated in a broad range of aerospace, biomedical and sports equipment applications due to its unique combination of high mechanical strength, light weight and good biocompatibility. However, Ti implants are often subject to wear in specific areas. Therefore, the improvement of mechanical properties, such as hardness, wear resistance, bearing capability of implants is a key point to broaden the application fields of titanium. Cubic boron nitride (cBN) is a well-known superhard material possessing high chemical stability and biocompatibility. However, cBN suffers from poor machinability and sinterability. Attempts to process boron nitride by laser treatment into intricate shapes are extremely difficult, expensive and time-consuming tasks squeezing its applicability. In this work, manufacturing of Ti/cBN cellular structures and solid parts of high strength and good wear resistance by selective laser melting was performed. In Ti/cBN composite powder, the boron nitride provides the excellent mechanical properties, and titanium promotes the laser absorption improving the process of densification. The parametric study of consolidation process has been performed and the microstructural features along with mechanical properties are examined.
Investigation of Properties of Coated Hollow Mini-Spheres
Authors: Mironovs Viktors , Tatarinov Alexey , Blumbergs Ervins , Boiko Irina
Published: April 2019

Metal hollow mini-spheres (MHMS) present a basis for the creation of new structured materials due to their low weight and energy adsorption capacity. Typically, MHMS are made of steel with a high level porosity in the sphere’s wall 80-110 microns thick. Modification of the outer surface by copper coating of 20-30 microns imposed by vacuum sputtering provides several times higher electrical conductivity, lower porosity of the outer layer and smoother surface, preserving light weight and flotation properties. This modification will provide better possibilities for spheres’ consolidation by means of sintering and electric brazing and creation of new cellular structures.
The Effect of Spark Plasma Sintering Thermal Cycle on Behaviour of Fe-Based Hardfacings Reinforced with WC and WC-Based Hardmetal
Authors: Katinas Egidijus , Antonov Maksim , Jankauskas Vytenis , Tarraste Marek
Published: April 2019

The effect of composite materials reinforcement by hardmetal with various size of particles (WC 710-1000 μm, recycled WC-Co 710-800 μm and pure WC 10 μm) with Fe-based matrix thermally affected by spark plasma sintering (SPS) method at temperatures 1100°C, 1200°C and 1280°C was studied. The analysis of samples cross-section was performed with SEM and EDS to illustrate distribution of elements after thermal influence. The aim of this research was an investigation of diffusion process behaviour between Fe-based matrix and WC and WC based hardmetal particles at various temperatures. Results help to identify and understand melting and solidification of grains affected at high temperature. Similar temperatures are used for surfacing and repair of worn parts and recycled tungsten carbide particles (as reinforcement) could be used during manual or plasma transferred arc welding.
Effect of Thermal Spraying Method on the Microstructure and Wear Behaviour of FeNiCrBSiC-CrB2 Coating
Authors: Umanskyi Oleksandr , Storozhenko Maryna , Antonov Maksim , Terentyev Oleksandr , Koval O. , Goljandin Dmitri
Published: April 2019

In this study, the influence of plasma and detonation spraying techniques on the microstructure and wear behaviour of FeNiCrBSiC-20wt%CrB2 coating was investigated. The obtained coatings were found to comprise of Fe, Ni-based solid solution matrix reinforced with mixed boride phases (Fe,Cr)2B, (Ni,Fe,Cr)B, (Cr,Fe,Ni, Mo)B. The main microstructural differences of the plasma and detonation sprayed coatings are the morphology, the size and the distribution of hard boride particles. The tribological behaviour of coatings was examined under dry sliding conditions against Al2O3 ball at 20, 200 and 400 °C. The wear loss of detonation sprayed coatings was slightly lower at high temperatures while plasma sprayed coating had same wear at all temperatures. The investigation of worn surfaces revealed that abrasive and oxidative wear mechanisms are proved to be dominant for FeNiCrBSiC−20wt.%CrB2 plasma sprayed coatings, while brittle delamination and oxidative wear are characteristic for detonation sprayed coating. The sliding wear loss of the unreinforced commercial FeNiCrBSiC plasma sprayed coating was 2-3 times higher than that of reinforced (with chromium boride) coating at high temperatures due to splat delamination.
Development of Testing Method for Assessment of Release Agent Effectiveness in High Temperature Forming Processes
Authors: Widder Lukas , Nevosad Andreas , Reichmann Frank , Adam Karl
Published: April 2019

Compaction of granular raw materials is a crucial process in modern heavy industries. Extreme operating conditions such as high temperatures, high loads and high press rotational velocities are applied in applications such as hot briquetting processes. For fast and smooth removal from the mold, the adhesion forces are a crucial parameter. To set up a model test for investigations of the adhesive behavior of several release agents under application-oriented harsh operating conditions an available forming tribometer was adapted. Special release agents to reduce adhesive wear and improve the release properties are considered. Surfaces and wear tracks of test samples were characterized by means of optical microscopy, 3D-topographical evaluation as well as SEM analysis. The benefit of the release agents on the subjacent microstructure was evaluated on cross-sections of tribo-stressed areas. Resulting adhesion forces could be well distinguished for all release agents and significant improvements to uncoated operating conditions were achieved. It was proven that the developed test instrumentation is suited to characterize the performance of release agents. The obtained results strongly indicate a significant decrease of severe surface deteriorations when suitable release agents are applied.
Investigation of Steam Turbine Blades Damage and Reliability in a Power Plant
Authors: Molodtsov Artjom , Dedov Andrei , Klevtsov Ivan , Kommel Lembit , Lausmaa Toomas , Mikli Valdek
Published: April 2019

This work presents an experimental case study of 200 MW low-pressure steam turbine rotor blades damage after 310 thousand hours of operation and 404 start-ups on the power plant. Damaged blade material was analysed by experimental testing of mechanical properties as well as crack initiation and microstructure in the damaged area by using optical and scanning electron microscopes, and investigation of chemical composition by the SEM-EDS method. Results of the investigation show that the material was die forged martensitic steel 20Cr13. The mechanical properties of the blade steel were in accordance with standard technical requirements for new material. The cross-sections of damaged and undamaged blades were investigated and compared. It was found that thickness of damaged blades was significantly less than undamaged ones. SEM-EDS analysis has shown the presence of brass fragment on the surface of one damaged blade. The microstructural analysis has shown that one of the cracks was initiated due to impact of brass fragment. Based on the given case study results it is concluded that the reason of the blade damage was a combination of at least two factors: accelerated high cycle fatigue due to increased stresses caused by excessive vibration of damaged blades with lower thickness and impact of brass fragment against blades.
Recycling of Niobium Slag by Disintegrator Milling
Authors: Kulu Priit , Goljandin Dmitri , Külaviir Jaan , Hain Tiina , Kivisto Mart
Published: April 2019

The main aim of the study is recycling of niobium slag, separating valuable metallic Nb and mineral ballast – calcium aluminate. Niobium slag is a waste product from Nb production at NPM Silmet OÜ. For the retreatment of slag, an efficient disintegrator milling technology was used. Laboratory grindability tests of slags were carried out. We propose a potential principal scheme of slag treatment, consisting of preliminary size reduction by impact milling at direct mode and final at separative mode using a disintegrator milling system DSL-115. As a result of slag pretreatment, pure Nb from a coarse fraction was separated. To elaborate an industrial technology, semi-industrial tests for specifying recycling modes and finding optimal milling parameters were performed. Granulometry studies of milled products and chemical composition as of Nb as well as that of remained products were conducted. Yield of Nb with purity 90–95% was in the range of 0.4–1.0%. Preliminary cement tests for using the main product as a binder or a substitute of cement confirmed its potential for use in building materials production.
Dlg1 Maintains Dendritic Cell Function by Securing Voltage-Gated K+ Channel Integrity
Authors: Dong Xuejiao , Wei Lisi , Guo Xueheng , Yang Zhiyong , Wu Chuan , Li Peiyu , Lu Lu , Qi Hai , Shi Yan , Hu Xiaoyu , Wu Li , Chen Liangyi , Liu Wanli
Published: April 2019

Dendritic cells (DCs) play key roles in Ab responses by presenting Ags to lymphocytes and by producing proinflammatory cytokines. In this study, we reported that DC-specific knockout of discs large homologue 1 (Dlg1) resulted in a significantly reduced capacity to mediate Ab responses to both thymus-independent and thymus-dependent Ags in Dlg1fl/flCd11c-Cre-GFP mice. Mechanistically, Dlg1-deficient DCs showed severely impaired endocytosis and phagocytosis capacities upon Ag exposure. In parallel, loss of Dlg1 significantly jeopardized the proinflammatory cytokine production by DCs upon TLR stimulation. Thus, Dlg1-deficient DCs lost their functions to support innate and adaptive immunities. At a cellular level, Dlg1 exhibited an indispensable function to maintain membrane potential changes by securing potassium ion (K+) efflux and subsequent calcium ion (Ca2+) influx events in DCs upon stimulation, both of which are known to be required for proper function of DCs. At a molecular level, Dlg1 did so by retaining the integrity of voltage-gated K+ channels (including Kv1.3) in DCs. The loss of Dlg1 led to a decreased expression of K+ channels, resulting in impaired membrane potential changes and, as a consequence, reduced proinflammatory cytokine production, compromised Ag endocytosis, and phagocytosis. In conclusion, this study provided, to our knowledge, a novel insight into Dlg1 and the voltage-gated K+ channels axis in DC functions.
Endoscopic third ventriculostomy in children with failed ventriculoperitoneal shunt
Authors: Heshmati Bijan , Habibi Zohreh , Golpayegani Mehdi , Salari Farhad , Anbarlouei Mousarreza , Nejat Farideh
Published: April 2019

Context: Endoscopic third ventriculostomy (ETV) is an accepted procedure for the treatment of obstructive hydrocephalus. The role of endoscopic treatment in the management of shunt malfunction was not extensively evaluated. The aim of this study is to evaluate the success rate of ETV in pediatric patients formerly treated by ventriculoperitoneal (V-P) shunt implantation. Materials and Methods: Thirty-three patients with their first shunt failure and obstructive hydrocephalus in brain imaging between 2008 and 2014 were enrolled in this study. Results: The most common causes of hydrocephalus in these patients were aqueductal stenosis and myelomeningocele with or without associated shunt infection. Of these 33 cases, 20 ETV procedures were successful, and 13 cases needed shunt revision after ETV failure. There was no serious complication during ETV procedures. The follow-up period of patients with successful ETV was 6–50 months (mean 18 months). The time interval between ETV and new shunting subsequent to ETV failure was 24.4 days (10–95). Conclusions: ETV can be considered as an alternative treatment paradigm in patients with previous shunt or new shunt failure with an acceptable success rate of 6o%, although long-term follow-up is needed for these patients.
The Dose Makes the Poison*
Authors: Perreault Marc M
Published: April 2019

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Departmental Initiative to Improve Documentation in the Medical Record by Acute Care Pharmacists
Authors: Zimmer Stephanie , Gray Carolyn , Roy Caitlin , Semchuk William M
Published: April 2019

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Has the Time Come to Abandon Routine Use of Unfractionated Heparin in the Hospital Setting?
Authors: Guirguis (Pro) Micheal , Semchuk (Con) William M
Published: April 2019

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The Pharmacist Guide to Implementing Pharmaceutical Care
Authors: Dahri Karen
Published: April 2019

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Congratulations to the 2018 Recipients of Foundation Grants and Scholarships
Authors: Authors Various
Published: April 2019

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H-Point Machine (HPM-II) - Procedure for H-Point Determination - Benchmarking Vehicle Seats
Authors:   Human Accom and Design Devices Stds Comm
Published: April 2019

Benchmarking is used to discover the design intent measurements for seating compartments in vehicles when these measurements are either unknown or are specified using differing measurement procedures.

This document provides the specifications and procedures to establish consistent measurements for benchmarking vehicle seating positions using the H-Point Machine (HPM-II1) described in SAE J4002 and the H-Point Design tool (HPD) described in SAE J4004. The HPM-II is a physical tool used to establish key reference points and measurements in a vehicle (Figure 1). The HPD is a CAD tool that aids in the benchmarking process (see Appendix A and SAE J4004).
Surveillance of SO2 and NO2 from ship emissions by MAX-DOAS measurements and implication to compliance of fuel sulfur content
Authors: Cheng Yuli , Wang Shanshan , Zhu Jian , Guo Yanlin , Zhang Ruifeng , Liu Yiming , Zhang Yan , Yu Qi , Ma Weichun , Zhou Bin
Published: April 2019

Abstract. With the increased concerns on the shipping emitted air pollutants, the feasible technology for the surveillance is in high demand. Here we presented the shore-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of emitted SO2 and NO2 from ships under different traffic conditions in China's ship emission control area (ECA) of Shanghai and Shenzhen, China. These three typical measurement sites are used to represent emission scenarios of ship docked at berth, navigation in the inland waterway and inbound/outbound in the deep water port. With 2-dimensional scanning, the observation shows that the hotspots of SO2 and NO2 can be quickly and easily located from multiple berth. Although the MAX-DOAS measurements can not distinguish the single ship plume in the busy shipping lanes of inland waterway area, it certificates that the variations of SO2 and NO2 levels are mainly impacted by the ship traffic density and atmospheric dispersion conditions. In the open water area with low density of vessels, the MAX-DOAS measurements can capture the pulse signal of ship emitted SO2 and NO2 very well, and characterize the peaks altitude and insistent duration of the individual ship plumes. Combined with the ship information of activity data, rated power of engine and fuel sulfur content, it was found that SO2 / NO2 ratio in single plume is usually low (
Above-Cloud Aerosol Radiative Effects based on ORACLES 2016 and ORACLES 2017 Aircraft Experiments
Authors: Cochrane Sabrina P. , Schmidt K. Sebastian , Chen Hong , Pilewskie Peter , Kittelman Scott , Redemann Jens , LeBlanc Samuel , Pistone Kristina , Kacenelenbogen Meloë , Segal Rozenhaimer Michal , Shinozuka Yohei , Flynn Connor , Platnick Steven , Meyer Kerry , Ferrare Rich , Burton Sharon , Hostetler Chris , Howell Steven , Dobracki Amie , Doherty Sarah
Published: April 2019

Abstract. Determining the direct aerosol radiative effect (DARE) of absorbing aerosols above clouds from satellite observations alone is a challenging task, in part because the radiative signal of the aerosol layer is not easily untangled from that of the clouds below. In this study, we use aircraft measurements from the NASA ObseRvations of CLouds above Aerosols and their intEractionS (ORACLES) project in the southeast Atlantic to derive it with as few assumptions as possible. This is accomplished by using spectral irradiance measurements (Solar Spectral Flux Radiometer, SSFR) and aerosol optical depth (AOD) retrievals (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research, 4STAR) during vertical profiles (spirals) that minimize the albedo variability of the underlying cloud field – thus isolating aerosol radiative effects from those of the cloud field below. For two representative cases, we retrieve spectral aerosol single scattering albedo (SSA) and the asymmetry parameter (g) from these profile measurements, and calculate DARE given the albedo range measured by SSFR on horizontal legs above clouds. For mid-visible wavelengths, we find SSA values from 0.80–0.85, and a significant spectral dependence of g. As the cloud albedo increases, the aerosol increasingly warms the column. The transition from a cooling to a warming top-of-aerosol radiative effect (the critical albedo) occurs just above 0.2 in the mid-visible. In a companion paper, we use the techniques introduced here to generalize our findings to all 2016 and 2017 measurements, and parameterize aerosol radiative effects.
Validation and application of optimal ionospheric shell height model for single-site estimation of total electron content
Authors: Zhao Jiaqi , Zhou Chen
Published: April 2019

Abstract. We recently proposed a method to establish an optimal ionospheric shell
height model based on the international GNSS service (IGS) station data and
the differential code bias (DCB) provided by the Center for Orbit Determination
in Europe (CODE) during the time from 2003 to 2013. This method is very
promising for DCB and accurate total electron content (TEC) estimation by
comparing to the traditional fixed shell height method. However, this method
is basically feasible only for IGS stations. In this study, we investigate
how to apply the optimal ionospheric shell height derived from IGS station
to non-IGS stations or isolated GNSS receivers. The intuitive and practical
method to estimate TEC of non-IGS stations is based on optimal ionospheric
shell height derived from nearby IGS stations. To validate this method, we
selected two dense networks of IGS stations located in regions in the US and
Europe. Two optimal ionospheric shell height models are established by two
reference stations, namely GOLD and PTBB, which are located at the
approximate center of two selected regions. The predicted daily optimal
ionospheric shell heights by the two models are applied to other IGS
stations around these two reference stations. Daily DCBs are calculated
according to these two optimal shell heights and compared to respective DCBs
released by CODE. The validation results of this method are as follows. (1) Optimal ionospheric shell height calculated by IGS stations can be applied
to its nearby non-IGS stations or isolated GNSS receivers for accurate TEC
estimation. (2) As the distance away from the reference IGS station becomes
larger, the DCB estimation error becomes larger. The relation between the
DCB estimation error and the distance is generally linear.
Budget of the total nitrogen in the Yucatan Shelf: driving mechanisms through a physical-biogeochemical coupled model
Authors: Estrada-Allis Sheila N. , Azevedo Correia de Souza Joao M. , Sheinbaum Pardo Julio , Henriquez Ortiz Cecilia , Mariño-Tapia Ismael , Herrera-Silveira Jorge A.
Published: April 2019

Abstract. Continental shelves are the most productive areas in the seas with strongest implications for global Total Nitrogen (TN) cycling. The Yucatan shelf is the largest shelf in the Gulf of Mexico (GoM), however, its general TN budget has not been quantified. This is largely due to the lack of significant spatio-temporal in situ measurements and the complexity of the shelf dynamics, including the Yucatan Current, coastal upwelling, Coastal Trapped Waves (CTWs) and bottom Ekman transport. Through a nine years output of a coupled physical-biogeochemical model of the GoM, the TN budget in the Yucatan shelf is quantified. Results indicate that the main entrance of inorganic nitrogen is through its southern and eastern margins. The TN is then advected to the oligotrophic deep GoM and to the deep Campeche bay. The analysis also shows that the inner shelf (50 m isobath) is efficient in terms of TN, since all the DIN imported into the shelf is consumed by the phytoplankton. Rivers contribute 20 % of the TN, while denitrification removes up to 53 % of TN that enters into the inner shelf. The high-frequency variability of the TN fluxes are modulated by the Yucatan Current in the south and by bottom Ekman transport produced by this current against the shelf-break (250 m isobath) in the east. This current-topography interaction can help to maintain the upwelling of Cape Catoche, uplifting nutrient-rich water into the euphotic layer. The export of TN at both western and northwestern margins is modulated by CTWs with a mean period of 10 days in agreement with recent observational and modelling studies.
Vertical partitioning of CO2 production in a Dystric Cambisol
Authors: Wordell-Dietrich Patrick , Don Axel , Wotte Anja , Rethemeyer Janet , Bachmann Jörg , Helfrich Mirjam , Kirfel Kristina , Leuschner Christoph
Published: April 2019

Abstract. Large amounts of total organic carbon are temporarily stored in soils, which makes soil respiration one of the major sources of terrestrial CO2 fluxes within the global carbon cycle. More than half of global soil organic carbon (SOC) is stored in subsoils (below 30 cm), which represent a significant C pool. Although several studies and models have investigated soil respiration, little is known about the quantitative contribution of subsoils to total soil respiration or about the sources of CO2 production in subsoils. In a two-year field study in a European beech forest in northern Germany, vertical CO2 concentration profiles were continuously measured at three locations and CO2 production quantified in the topsoil and the subsoil. To determine the contribution of fresh litter-derived C to CO2 production in the three soil profiles, an isotopic labelling experiment using 13C-enriched leaf litter was performed. Additionally, radiocarbon measurements of CO2 in the soil atmosphere were used to obtain information about the age of the C source in CO2 production. At the study site, it was found that 90 % of total soil respiration was produced in the first 30 cm of the soil profile where 53 % of the SOC stock is stored. Freshly labelled litter inputs in the form of dissolved organic matter were only a minor source for CO2 production below a depth of 10 cm. In the first two months after litter application, fresh litter-derived C contributed on average 1 % at 10 cm depth and 0.1 % at 150 cm depth to CO2 in the soil profile. Thereafter, its contribution was less than 0.3 % and 0.05 % at 10 cm and 150 cm depths respectively. Furthermore CO2 in the soil profile had the same modern radiocarbon signature at all depths, indicating that CO2 in the subsoil originated from young C sources, despite a radiocarbon age bulk SOC in the subsoil. This suggests that fresh C inputs in subsoils in the form of roots and root exudates are rapidly respired and that other subsoil SOC seems to be relatively stable. The field labelling experiment also revealed a downward diffusion of 13CO2 in the soil profile against the total CO2 gradient. This isotopic dependency should be taken into account when using labelled 13CO2 and 14C isotope data as an age proxy for CO2 sources in the soil.
Development of a new distributed hybrid seismic-electrical data
acquisition station based on system–on-a-programmable-chip
technology
Authors: Zhang Qisheng , Li Wenhao , Guo Feng , Yuan Zhenzhong , Qiao Shuaiqing , Zhang Qimao
Published: April 2019

Abstract. In the past few decades, with the continuous advancement of technology, seismic-electrical instruments have developed rapidly. However, complex and harsh exploration environments have put forward higher requirements and severe challenges for traditional geophysical exploration methods and instruments. Therefore, it is extremely urgent to develop new high-precision exploration instruments and data acquisition systems. In this study, a new distributed seismic-electrical hybrid acquisition station is developed using system-on-a-programmable-chip (SoPC) technology. The acquisition station hardware includes an analog board and a main control board. The analog board uses a signal conditioning circuit and a 24-bit analog-to-digital converter (ADS1271) to achieve high-precision data acquisition, while the main control board uses a low-power SoPC chip to enable high-speed stable data transmission. Moreover, the data transmission protocol for the acquisition station was designed, an improved low-voltage differential signaling data transmission technology was independently developed, and a method to enhance the precision of synchronous acquisition was studied in depth. These key technologies, which were developed for the acquisition station, were integrated into the SoPC of the main control board. Testing results indicate that the synchronization precision of the acquisition station is better than 200 ns, and the maximum low-power data transmission speed is 16 Mbps along a 55 m cable. Simultaneously, the developed acquisition station has the advantages of low noise, large dynamic range, low power consumption, etc., and it can achieve high-precision hybrid acquisition of seismic-electrical data.
The Canadian Hydrological Model (CHM): A multi-scale, multi-extent, variable-complexity hydrological model – Design and overview
Authors: Marsh Christopher B. , Pomeroy John W. , Wheater Howard S.
Published: April 2019

Abstract. Despite debate in the rainfall-runoff hydrology literature about the merits of physics-based and spatially distributed models, substantial work in cold regions hydrology has shown improved predictive capacity by including physics-based process representations, relatively high-resolution semi- and fully-distributed discretizations, and use of physically identifiable parameters with limited calibration. While there is increasing motivation for modelling at hyper-resolution (