Comment on "Motion of a helical vortex filament in superfluid 4He under the extrinsic form of the local induction approximation"

We comment on the paper by Van Gorder ["Motion of a helical vortex filament in superfluid ${}^4$He under the extrinsic form of the local induction approximation", Phys. Fluids 25, 085101 (2013)]. We point out that the flow of the normal fluid component parallel to the vortex will often lead into the Donnelly-Glaberson instability, which will cause the amplification of the Kelvin wave. We explain why the comparison to local nonlinear equation is unreasonable, and remark that neglecting the motion in the $x$-direction is not reasonable for a Kelvin wave with an arbitrary wave length and amplitude. The correct equations in the general case are also derived

Pakettisynkronointitestauksen automaatio

Telecommunications network operators are shifting from circuit switched backhaul technologies into packet switched networks to save costs with increasing traffic loads. Frequency synchronization was inherently provided by the circuit switched network, but has to be provided by other means in packet switched networks. One solution is Precision Time Protocol (PTP), defined in IEEE standard 1588, which can be used to create a master-slave synchronization strategy to a network. Synchronization quality is an essential factor when using any synchronization technology. Packet synchronization quality requirements in different situations are defined in ITU-T recommendation G.8261. The objective of this thesis is to create test automation for ITU-T recommendation G.8261 Appendix VI performance test cases 12 through 17 for Precision Time Protocol. Hypothesis is that this automation will make testing more effective than if testing was done manually, allowing testing of more products in a smaller time frame. Automated test system was planned and implemented with various measurement and impairment devices, and testing software to utilize them and to generate results. As a result, PTP synchronization quality testing efficiency was increased by over 20% while reducing the possibility for human errors.Verkko-operaattorit vaihtavat matkapuhelinverkoissa käyttämiään tekniikoita piirikytkentäisistä pakettikytkentäisiin säästääkseen kustannuksia kasvavien liikennemäärien kanssa. Piirikytkentäisissä verkoissa taajuussynkronointi leviää verkkoteknologian myötä automaattisesti koko verkkoon, mutta pakettikytkentäisissä verkoissa se täytyy tuottaa muilla tavoin. Yksi ratkaisu ongelmaan on Precision Time Protocol (PTP), joka on määritelty IEEE standardissa 1588, ja jolla voidaan luoda verkkoon isäntä–renki -synkronointistrategia. Synkronoinnin laatu on keskeinen tekijä kaikissa synkronointiteknologioissa. Pakettisynkronoinnin laatuvaatimuksia eri tapauksissa on määritelty ITU-T suosituksessa G.8261. Tämän diplomityön tavoitteena on luoda testausautomaatio ITU-T suosituksen G.8261 liitteen VI suorituskykytesteille 12–17 käyttäen PTP:tä. Hypoteesina on, että automaation avulla testauksesta tulee tehokkaampaa, kuin jos samat testit suoritettaisiin manuaalisesti. Näin entistä useammat tuotteet saataisiin testattua entistä lyhyemmässä ajassa. Automatisoitu testausjärjestelmä suunniteltiin ja toteutettiin käyttäen valikoimaa erilaisia mittauslaitteita ja verkkoemulaattoreita, sekä näiden laitteiden hallintaan kehitettyä testausohjelmistoa. Lopputuloksena PTP-synkronointitestauksen nopeus parani yli 20 prosenttia ja inhimillisten virheiden mahdollisuus väheni

Efficient and Selective Recovery of Trace Scandium by Inorganic Titanium Phosphate Ion-Exchangers from Leachates of Waste Bauxite Residue

The research leading to these results has received funding from the European Union (EU) Horizon 2020 Programme Marie Skłodowska-Curie actions under Grant Agreement no. 636876 (MSCA-ETN REDMUD).Bauxite residue (BR) is an inevitable industrial waste generated through the classic Bayer extraction of alumina from bauxite minerals. It contains relatively significant amount of valuable rare earth elements, including scandium, and therefore, we explored the suitability of trace scandium recovery from BR acid leachate by titanium phosphate (TiP) ion exchangers. Three kinds of TiP materials (amorphous TiP, α-TiP, and γ-TiP) were synthesized through fluorine-free precursors and characterized by chemical analysis, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR), ultraviolet/visible (UV/vis) diffuse reflectance spectrometry, 31P magic angle spinning (MAS) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), and potentiometric titration. The Sc3+ exchange capacities were determined as 1.74, 0.55, and 0.22 mequiv g–1 for amorphous, α-, and γ-TiP, respectively. Competition of major elements (Fe, Al, Ca) in BR leachate with Sc uptake were studied in batch experiments using binary equimolar mixtures, and the separation factors of Sc/Fe2+, Sc/Al, and Sc/Ca reached magnitudes of 10–1000 on amorphous TiP. The high Sc3+selectivity by amorphous TiP was suspected to be the matching of Ti4+ lattice radius with Sc3+ ionic radius (both 0.745 Å). Finally, the separation of trace scandium from the simulated BR leachate solution was demonstrated on an amorphous TiP column. The interference of Fe3+ has been partially resolved by on-column reduction using sodium sulphite. The optimized final eluate contained only Sc, Fe, and Al. The concentration ratio of Sc/Fe can be increased by a factor of 8.8 and Sc/Al by 265 through a single cycle of chromatographic separation with an Sc recovery rate of 91.1%.Peer reviewe

Leapfrogging Kelvin waves

Two vortex rings can form a localized configuration whereby they continually pass through one another in an alternating fashion. This phenomenon is called leapfrogging. Using parameters suitable for superfluid helium-4, we describe a recurrence phenomenon that is similar to leapfrogging, which occurs for two coaxial straight vortex filaments with the same Kelvin wave mode. For small-amplitude Kelvin waves we demonstrate that our full Biot-Savart simulations closely follow predictions obtained from a simplified model that provides an analytical approximation developed for nearly parallel vortices. Our results are also relevant to thin-cored helical vortices in classical fluids

Separation of cobalt, neodymium and dysprosium using amorphous zirconium phosphate

The purpose of this study was to investigate the separation of Co, Nd and Dy from a ternary Co-Nd-Dy solution using amorphous zirconium phosphate (am-ZrP). Am-ZrP was synthesized by a precipitation method at room temperature and subsequently characterized by Fourier transform-infrared spectrometry, thermogravimetry, scanning electron microscopy, X-ray diffraction, solid-state 31P magic angle spinning nuclear magnetic resonance spectrometry and sodium hydroxide titration (with and without background salt). The ion exchange kinetics of am-ZrP that were determined in ternary 1 mM equimolar solutions at equilibrium pH 2.5. The effect of pH on the adsorption was studied in ternary 1 mM equimolar solutions and the uptakes of the metals increased with increasing pH until approximately pH 3.5. The adsorption isotherms of Co, Nd and Dy were tested in a series of ternary equimolar solution, the total uptake amounted to 4.13 meq/g at pH ~ 3.0. The preference of am-ZrP for these metals occurred in decreasing order Dy > Nd ≫ Co. The separation of Co, Nd and Dy from their 1 mM equimolar ternary mixture was investigated on an am-ZrP column. Effects of loading (7.8%, 62% and 100%) on the separation were compared by measuring the corresponding HNO3 elution fractions. It was found that with a lower metal loading of 7.8%, three clear elution bands were obtained. Am-ZrP exhibited selective separation properties towards the ternary Co-Nd-Dy system, which contribute to the future scale-up studies for the recycling of NdFeB magnets.Peer reviewe

The effect of phosphonates on lanthanide separation for surface-grafted porous zirconia

The effect of phosphonate groups on selective lanthanide sorption for a series of inorganic-organic hybrid materials was investigated. Four functional ligands with an increasing number of aminomethylenephosphonate groups were attached to the porous zirconia matrix via the post-synthetic grafting method. Successful surface grafting was confirmed by FTIR and P-31 MAS-NMR spectroscopies. All the synthesized hybrids showed a lanthanide uptake of about 100 mu mol g(-1) at pH 3. The sorption studies revealed that the hybrids of ligands with a larger number of phosphonate groups possess higher selectivity, as one with the largest number showed a separation factor of over 80 for La3+ and Lu3+. Fixed-bed column experiments also demonstrated the materials' favored uptake of Lu3+ over La3+ at pH 3, in addition to the reusability and applicability to the actual separation settings. These results propose strategies for the selection of organic ligands for hybrid sorbent synthesis.Peer reviewe

Intralanthanide Separation on Layered Titanium(IV) Organophosphate Materials via a Selective Transmetalation Process

The lanthanides (Ln) are an essential part of many advanced technologies. Our societal transformation toward renewable energy drives their ever-growing demand. The similar chemical properties of the Ln pose fundamental difficulties in separating them from each other, yet high purity elements are crucial for specific applications. Here, we propose an intralanthanide separation method utilizing a group of titanium(IV) butyl phosphate coordination polymers as solid-phase extractants. These materials are characterized, and they contain layered structures directed by the hydrophobic interaction of the alkyl chains. The selective Ln uptake results from the transmetalation reaction (framework metal cation exchange), where the titanium(IV) serves as sacrificial coordination centers. The “tetrad effect” is observed from a dilute Ln3+ mixture. However, smaller Ln3+ ions are preferentially extracted in competitive binary separation models between adjacent Ln pairs. The intralanthanide ion-exchange selectivity arises synergistically from the coordination and steric strain preferences, both of which follow the reversed Ln contraction order. A one-step aqueous separation of neodymium (Nd) and dysprosium (Dy) is quantitatively achievable by simply controlling the solution pH in a batch mode, translating into a separation factor of greater than 2000 and 99.1% molar purity of Dy in the solid phase. Coordination polymers provide a versatile platform for further exploring selective Ln separation processes via the transmetalation process.Peer reviewe

Ammatillisen koulutuksen osaamisperusteisuus, asiakaslähtöisyys ja toiminnan tehokkuus – Osaamisperusteisuuden tila

Arvioinnin painopisteinä olivat ammatillisen koulutuksen osaamisperusteisuus, asiakaslähtöisyys ja toiminnan tehokkuus, joiden toteutumista tarkasteltiin koulutuksen järjestäjien johdon, opettajien, opiskelijoiden ja työelämän edustajien näkökulmasta. Arviointi kohdistui tutkintotavoitteiseen ammatilliseen koulutukseen (perus-, ammatti- ja erikoisammattitutkinnot) ja sen tavoitteena oli varmistaa osaltaan ammatillisen koulutuksen reformin painopisteitä koskevien valintojen osuvuus. Osaamisperusteisuus ja työelämälähtöisyys ovat olleet ammatillisen koulutuksen lähtökohtina jo noin kahdenkymmenen vuoden ajan. Ammatillisen peruskoulutuksen viimeisimmässä tutkinnon uudistuksessa (voimaan 1.8.2015) osaamisperusteisuus nostettiin koko tutkintouudistuksessa keskeiseksi asiaks

Sukupuoli ja matemaattis-luonnontieteelliset ja tekniset alat vanhempien ja nuorten välisissä koulutus- ja urakeskusteluissa

Tutkimuksessa selvitettiin yläkoululaisten vanhempien näkemyksiä sukupuolen merkityksestä nuoren koulutus- ja uravalinnoissa ja niihin liittyvissä keskusteluissa. Tutkimusaineisto (N=103) kerättiin sähköisellä kyselylomakkeella. Tulosten mukaan lähes puolet vanhemmista ei keskustele lastensa kanssa sukupuolen vaikutuksesta koulutus- ja uravalinnoissa, ja selkeä enemmistö vanhemmista ajatteli, että nuoren sukupuoli ei vaikuta näihin keskusteluihin. Yli puolet vanhemmista kertoi keskustelleensa lastensa kanssa matemaattis-luonnontieteellisten ja teknisten alojen mahdollisuuksista, vaikkakaan vanhemmat eivät näitä aloja koe tuntevansa kovin hyvin. Tulosten mukaan äidit tuntevat sukupuolen mukaisen eriytymisen vaikutuksia isiä paremmin. Vanhemmille tulisi tarjota ajantasaista tietoa näistä aloista, jotta he osaisivat tukea nuoria suuntautumaan heitä kiinnostaville koulutus- ja urapoluille sukupuolesta riippumatta

Calibration of RADMON radiation monitor onboard Aalto-1 CubeSat

RADMON is a small radiation monitor designed and assembled by students of University of Turku and University of Helsinki. It is flown on-board Aalto-1, a 3-unit CubeSat in low Earth orbit at about 500 km altitude. The detector unit of the instrument consists of two detectors, a Si solid-state detector and a CsI(Tl) scintillator, and utilizes the ΔE-E technique to determine the total energy and species of each particle hitting the detector. We present the results of the on-ground and in-flight calibration campaigns of the instrument, as well as the characterization of its response through extensive simulations within the Geant4 framework. The overall energy calibration margin achieved is about 5%. The full instrument response to protons and electrons is presented and the issue of proton contamination of the electron channels is quantified and discussed.RADMON is a small radiation monitor designed and assembled by students of University of Turku and University of Helsinki. It is flown on-board Aalto-1, a 3-unit CubeSat in low Earth orbit at about 500 km altitude. The detector unit of the instrument consists of two detectors, a Si solid-state detector and a CsI(Tl) scintillator, and utilizes the Delta E-E technique to determine the total energy and species of each particle hitting the detector. We present the results of the on-ground and in-flight calibration campaigns of the instrument, as well as the characterization of its response through extensive simulations within the Geant4 framework. The overall energy calibration margin achieved is about 5%. The full instrument response to protons and electrons is presented and the issue of proton contamination of the electron channels is quantified and discussed. (C) 2019 COSPAR. Published by Elsevier Ltd. All rights reserved.Peer reviewe