bluuebunny/crossref_metadata_2025 huggingface dataset:
Hot Toughness of Continuously Cast Steel Slabs during Reheating
Authors: Yang Bingye , Degischer H. Peter , Xia Guangmin , Presslinger Hubert
Published: December 2016

Laboratory hot tensile tests on specimens taken from continuously cast steel slabs are executed by means of a Gleeble apparatus to investigate the ductility and hot toughness of steels during reheating of as cast conditions. The reduction in area at fracture and the fracture energy for 10 different heats with the carbon content in the range from 0.003 to 0.521 mass% and some variations in Nb, Cr and N are presented in the temperature range from room temperature up to 1025°C. Ductility minima regarding toughness are identified around 300°C and 650°C. Relationships of the reduction in area at fracture and of the specific fracture energy with the relevant elements of the steel composition are established. Equivalent carbon concentrations are defined which take the N concentration into account for the 300°C embrittlement and additionally the micro‐alloying element Nb for the 650°C ductility minimum. Limits for the reduction in area values and for the specific fracture energy are proposed to validate the crack sensitivity of as cast carbon steel slabs.
Role of Direct Reduced Iron Fines in Nitrogen Removal from Electric Arc Furnace Steel
Authors: Pal J. , Ghosh S. , Goswami M. C. , Singh D. P. , Kumar Manoj , Minj R. K. , Upadhyay A. K.
Published: December 2016

Electric arc furnace steel contains about 70‐120 ppm nitrogen. There is no suitable method for nitrogen removal from electric arc furnace steel up to the level desired for good quality bars and flat rolled products (30 ppm max). The existing process based on vacuum degassing can remove only up to 20% of nitrogen in steel. In the present study DRI fines have been injected into a steel bath which can drift out nitrogen in steel through production of fine CO bubbles in‐situ on reaction with residual FeO in DRI fines and C in bath. For high and medium carbon steel, nitrogen got reduced to 30 ppm and 60 ppm respectively where initial nitrogen was 150 – 200 ppm in steel. Nitrogen removal also depends upon bath depth and addition level of DRI.
Effect of Microstructure on the Accelerated Creep of 20CrMoV12‐1 and P 91 Steels
Authors: Tuma Jelena Vojvodič , Kosec Gorazd
Published: December 2016

In the initial part the change of microstructure for steel X20 CrMoV 121 is discussed in terms of the distribution of carbide precipitates and its effects on accelerated creep resistance and hardness are presented. In the following, experimental results of microstructure and accelerated creep resistance are presented for the steels X20CrMoV 121 and P91 annealed for up to 8760 hours at 650°C and 750°C before the testing. A similar evolution of the distribution of carbide particles of a size above 102 nm is found for both steels, while the accelerated creep resistance is diminished much stronger for the steel X20CrMoV 121. This difference is due to a greater stability of NbC than that of VC precipitates, both related to the evolution of the chemical composition of complex chromium, molybdenum and iron carbide particles.
Examination of the Influence of Heat Treatment on the Properties of AI‐Si Alloys
Authors: Vuksanović Darko , Marković Srdjan , Petrović Stanka Tomović , Rakočević Snežana , Kovačević Kata , Tripković Snežana
Published: December 2016

In this paper the influence of heat treatment on the structural and mechanical properties of Al‐Si alloys was investigated. Silicon content in the examined alloys was in the range 11 to 14%, the contents of the other alloying elements were in the standard range [1] but all alloys were modified with strontium. The regime of the applied heat treatment was quenching (520°C/6h – cooling in water) + aging (205°C/7h –air cooling). The examinations were carried out at room temperature as well as at 250°C and 300°C. The obtained results showed a positive influence of the applied heat treatment on the mechanical properties of the examined alloys. The improvement of the mechanical properties can be considered as a consequence of a redistribution and change of morphology of the phases present in the structure of the alloys.
Mathematical Modelling and Experimental Investigation of Coke Reduction of FeO in Slag
Authors: Sun Haiping
Published: December 2016

Mathematic model development and experimental investigations were carried out for the reduction of FeO in slag by coke. Rate expressions for the reduction limited by the different steps and through different reaction routes were proposed. In the experimental investigation, the FeO reduction was found to be a first order and irreversible reaction; the reduction rate increased with increasing temperature and the FeO content in slag, and decreased with increasing ash content in the coke. Low CO2/CO ratio in the product gas and preferential reduction of FeO over SiO2 in slag were observed in the reaction system. The proposed reaction mechanisms were discussed with the observed kinetic phenomena. The reduction of FeO in slag by coke was found most likely to be jointly dominated by the mass transfer of FeO in slag and the chemical reactions at slag‐coke, slag‐gas or slag‐metal interfaces.
Experimental Study and Modelling of Viscosity of Chromium Containing Slags
Authors: Forsbacka Lasse , Holappa Lauri , Kondratiev Alex , Jak Evgueni
Published: December 2016

Viscosities of slags containing Al2O3, CaO, CrOx, MgO and SiO2 were measured in contact with metallic chromium using the rotating cylinder method. The modified Urbain model, developed at the University of Queensland, was extended to include MgO, CrO and Cr2O3, in addition to existing Al2O3, CaO, FeO and SiO2. Chromium oxides, in general, decrease the slag viscosity, although addition of trivalent oxide raises up the liquidus temperature and thus limits the measuring range. The model was able to describe the viscosity of complex slags reasonably well in most experimental cases.
Investigation of the Parameters Influencing the Accuracy of Rapid Steelmaking Slag Analysis with Laser‐Induced Breakdown Spectroscopy
Authors: Palagas C. , Stavropoulos P. , Couris S. , Angelopoulos G.N. , Kolm I. , Papamantellos D.C.
Published: December 2016

Laser‐Induced Breakdown Spectroscopy (LIBS) is used for the analysis of steelmaking slags (EAF, Ladle Furnace (LF) and Vacuum Ladle Degasser (VLD)). In view of the potential industrial application of LIBS for rapid slag analysis, relatively simple criteria were employed in order to obtain calibration curves for the elements of interest. The LIBS experiments were performed on samples prepared after crushing and milling to a size less than 0.2 mm and on as delivered solidified slag samples. In general, the analysis of the solidified as delivered slag samples exhibited better results than the corresponding analysis of the pressed slag, mainly for the elements distributed in the matrix. Thus, for LIBS application, the time consuming sample preparation of the slag can be avoided. According to the results obtained, the potential of LIBS technique for in‐situ, multi‐element analysis of slag was examined at the 60t‐ EAF of Helliniki Halyvourgia SA (HH‐Greece). The most important parameters that influence slag analysis are the laser pulse energy, the number of accumulated laser shots, the laser beam focusing conditions and the gating conditions of the detector. LIBS accuracy was found to depend on both the distribution of elements in the slag and on their environment (i.e. if they are embedded in the matrix or in a specific crystallized phase) as well. LIBS limitations for quantitative slag analysis are also discussed.

The accuracy of FeOn LIBS analysis for as delivered solidified EAF and VLD slags of the steel plant of Georgsmarienhütte was satisfactory showing a Regression Coefficient (RC) of 0.93 and 0.95 respectively. The accuracy of SiO2 and MgO analysis of VLD slags with RCs of 0.94 and 0.86 respectively was also satisfactory. In contrast, for the EAF slags the RC for MgO and SiO2, due to the observed non‐homogeneous crystallized phases have shown insufficient values, with 0.55 and 0.43 respectively. Similar results were gained for the FeOn, MgO and SiO2 analysis of the HH slags. Due to the higher intensity of scattering, the analysis of CaO, Al2O3 and Cr2O3 was of lower accuracy than for FeOn, MgO and SiO2.
High Strength Stainless Austenitic CrMnCN Steels – Part I: Alloy Design and Properties
Authors: Berns H. , Gavriljuk V.G. , Riedner S. , Tyshchenko A.
Published: December 2016

Generally the strength of stainless austenitic steels does not live up to their good corrosion resistance. Solid solution hardening by interstitial elements is a means of raising the strength, but is used only moderately because of poor weldability, which, however, is not required in various applications. The solubility of nitrogen is high in stainless austenite of steels with 18 mass% of Cr and Mn each, but low in the melt. Carbon reveals the opposite behaviour. Instead of producing high nitrogen steels by pressure metallurgy, about 1 mass% of C+N is dissolved in the melt at ambient pressure. The new cost‐effective C+N steel reaches a yield strength of 600 MPa, a true fracture strength above 2500 MPa and an elongation above 70 %. Conduction electron spin resonance revealed a high concentration of free electrons. Thus, the ductile metallic character of the C+N steel is enhanced, explaining the high product of strength times toughness. The high interstitial content requires rapid quenching to avoid an embrittling precipitation and respective intercrystalline corrosion.
High Strength Stainless Austenitic CrMnCN Steels ‐ Part II: Structural Changes by Repeated Impacts
Authors: Gavriljuk V.G. , Razumov O. , Petrov Yu. , Surzhenko I. , Berns H.
Published: December 2016

Phase transformations and changes in the structure caused by impact loading of steel Cr18Mn18CN alloyed with carbon+nitrogen are studied in comparison with Hadfield steel using X‐ray diffraction, Mössbauer spectroscopy and TEM. It is shown that the surface layer of all the studied steels impacted by mineral particles of greywacke remains austenitic, although their magnetic structure within a depth of about 10 μm is similar to that of martensite. TEM studies reveal a mixture of amorphous, nanocrystalline and thin‐twinned fcc crystal structures. The suggestion is made that the atomic configuration at the twin boundaries is similar to that in the bcc lattice and induces the high‐spin state of the iron atoms in the thin twins. At the same time, the amorphous structure of the surface layer can be also a source of ferromagnetism like this occurs in rapidly quenched FeSiB ribbons. The extremely high wear resistance of the newly developed CrMnCN steels and of Hadfield steel seems to be related to the impact‐induced surface structure in its amorphous + nanocrystalline + thin‐twinned austenitic states.
Model of Radial Distributions in the Upper Part of the Blast Furnace Shaft
Authors: Kodukula Suresh K. , Saxén Henrik
Published: December 2016

A mathematical model is developed to estimate the radial distribution of the ore‐to‐coke ratio in the blast furnace shaft on the basis of molar flow and energy balance equations. It utilizes the radial temperature distribution of the gas measured above the burden surface to estimate the thermal flow ratios in concentric rings of the shaft, and from this the ore‐to‐coke distribution under the assumptions that a thermal reserve zone of a given temperature exists in the furnace. The model, which also predicts the radial distribution of temperature and pressure in the shaft, has been evaluated on measurements from an industrial blast furnace and verified by comparing the results with temperatures from an in‐burden probe.
Effect of Mn, Si and Mn‐Si Alloying on the Precipitation of Ultra‐fine Oxides in Fe during Solidification
Authors: Li H. G. , Zheng S. B. , Zheng Q. , Wang L. W. , Zhai Q. J.
Published: December 2016

The effect of Mn, Si and Mn‐Si alloying on the precipitation of oxide inclusions in Fe during solidification has been investigated. The results show that the inclusions precipitating during solidification are relatively small and distribute uniformly in Mn, SI and Mn‐Si alloyed steels. Most of the inclusions are nearly spherical. The maximum diameter of inclusions is only 3.3μm in the three types of alloyed steels. The average size of inclusions is 1.3μm, 1.2μm and 1.1μm in Mn, Si and Mn‐Si alloyed steels, respectively. The maximum amount of inclusions is 1.1×105 per unit volume (mm−3) in Mn alloyed steel and the minimum is 5.8×104 per unit volume in Si alloyed steel. The volume fractions of the inclusions with Mn, Si and Mn‐Si alloying are 0.01%, 0.005% and 0.006%, respectively.
Dilatometric Studies on Copper Added Titanium‐Boron Steels
Authors: Ghosh S. K. , Haldar A. , Chattopadhyay P. P.
Published: December 2016

An attempt has been made to examine the effect of Cu addition in low carbon Ti ‐ B microalloyed steel on their continuous cooling transformation behaviour by dilatometric study. It has been demonstrated that addition of Cu by an amount of 1.5 wt% in Ti – B microalloyed steel effectively lowers the transformation start temperature. Addition of Ni (0.79 wt%) in 1.5 wt% Cu‐added Ti–B microalloyed samples further lowers the transformation temperature of austenite even at cooling rates comparable with air ‐ cooling condition. The microstructural investigation of the samples subjected to the dilatometric study under different cooling rates suggests the possibility of obtaining pearlite free multiphase microstructures in 1.5 wt% Cu – and 0.79 wt% Ni – added Ti – B microalloyed steel by air – cooling from the austenite region.
Wear Resistant Steels and Casting Alloys containing Niobium Carbide
Authors: Theisen Werner , Siebert Sabine , Huth Stephan
Published: December 2016

Niobium, like titanium and vanadium, forms superhard MC carbides that remain relatively pure in technical alloys on account of their low solubility for other metallic alloying elements. However, because they have a greater hardness than the precipitated chromium carbides commonly used in wear‐resistant alloys, they are suitable as alternative hard phases. This contribution deals with new wear‐resistant steels and casting alloys containing niobium carbide. These include a secondary hardening hardfacing alloy, a composite casting alloy for wear applications at elevated temperatures, a white cast iron as well as two variants of a corrosion‐resistant cold‐work tool steel produced by melt metallurgy and by powder metallurgy. A heat‐resistant casting alloy is also discussed. Based on equilibrium calculations the microstructures developing during production of the alloys are analysed, and the results are discussed with respect to important properties such as abrasive wear and corrosion resistance.
Effect of Nitrogen Alloying on Sulphur Behaviour during ESR of AISI M41 Steel
Authors: Mattar Taha , El‐Fawakhry Kamal , Halfa Hossam , Eissa Mamdouh
Published: December 2016

In this work, the effects of nitrogen alloying, physical properties and chemical composition of slag used in electro‐slag refining (ESR) on phosphorus and sulphur contents of AISI M41 high speed steel have been studied. The experiments were conducted with two high speed steel grades which were melted in an induction furnace (IF). The first grade is the standard AISI M41 high‐speed steel and the second one is nitrogen alloyed M41 (denoted M41N). The produced ingots were ESR remelted under three grades of calcium fluoride based slag. Results showed that the ESR process has no effect on the phosphorus content in steel but it is a good tool in removing sulphur. This study shows that a high desulphurization rate can be achieved by ESR process by optimizing slag properties where the viscosity and oxidation reactions play an important role in sulphur removal. Nitrogen alloying was found to retard sulphur removal.
Durability of Brick Lined Steel Ladles from a Mechanical Point of View
Authors: Gruber Dietmar , Harmuth Harald
Published: December 2016

The refractory lining in steel ladles is exposed to chemical and mechanical loads during the heats. Mechanical loads develop from the thermal expansion of the refractories which is confined either by the steel construction or by regions of different temperature within the refractory material. The aim of this work was the investigation of factors influencing the mechanical durability of refractory steel ladle linings and the clarification of failure mechanisms. Especially irreversible strains at the hot face of the working lining caused by compressive stresses induce an opening of joints at the hot face. The irreversible strains reduce the compressive stresses in circumferential direction and increase the probability of tensile failure. A further effect of the irreversible strains is a reduced stability of the working lining. Of special interest in this context is a possible controlled expansion of bricks to counterbalance the irreversible compressive strains.
Emerging Issues and Models in College Mental Health Services
Authors: Locke Ben , Wallace David , Brunner Jon
Published: December 2016

This chapter provides a brief overview of the psychological issues facing today's college students, information about students receiving mental health services, and an evidence‐based model describing the practice and functions of today's counseling centers.
Mental Health Concerns of Students on the Autism Spectrum
Authors: Brown Jane Thierfeld , Meeks Lisa , Rigler Michelle
Published: December 2016

This chapter introduces the reader to the autism spectrum and discusses the characteristics, traits, common concerns, and potential supports for this population. The chapter also provides some recommendations for proactive and collaborative support efforts for students with both an autism spectrum disorder and mental health issues.
A design guideline of parasitic inductance for preventing oscillatory false triggering of fast switching GaN‐FET
Authors: Umetani Kazuhiro , Yagyu Keisuke , Hiraki Eiji
Published: December 2016

Gallium nitride field‐effect transistors (GaN‐FETs) are attractive devices because of its low on‐state resistance and fast switching capability. However, they can suffer from false triggering caused by fast switching. Particularly, a disastrous oscillation of repetitive false triggering can occur after a turn‐off, which may deteriorate the reliability of power converters. To address this issue, we give a design guideline to prevent this phenomenon. We analyze a simple circuit model to derive the condition of occurrence of this phenomenon, which is then verified experimentally. Results show that the parasitic inductance of the gating circuit, Lg, and that of the decoupling circuit, Ld, should be designed so that the LC resonance frequency of Lg and the gate–source capacitance of the GaN‐FET does not coincide with that of Ld and the drain–source capacitance, respectively. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Magnetometer calibration improvement using wavelet and genetic algorithm
Authors: Hu Xiangchao , Pang Hongfeng , Fu Liangrui , Pan Mengchun
Published: December 2016

Three‐axis magnetometer error and measurement noise influence the accuracy of magnetic measurements. Genetic algorithm (GA) is proposed to calibrate the magnetometer error, and wavelet is proposed for noise cancellation. The noise of a Mag3300 magnetometer and a DM magnetometer were tested within a horizontal barrel shield equipment. Five kinds of wavelet analysis and two kinds of wavelet package were used for noise cancellation, and the performance of different wavelets was compared. Noise of the Mag3300 magnetometer and DM magnetometer were suppressed from 29.6 and 2.3466 to 3.7 and 1.0789 nT, respectively. The scalar error of the Mag3300 magnetometer was tested using a two‐dimensional nonmagnetic rotation equipment and a GSM‐19T proton magnetometer. Scalar calibration performances of the unscented Kalman filter (UKF), the two‐step algorithm, and GA were compared. Experimental results show that GA provides less error intensity (about 370 and 70 nT) than UKF and the two‐step algorithm. In addition, the influence of wavelet on scalar calibration using UKF, the two‐step algorithm, and GA was analyzed. Results show that wavelet improved the scalar calibration performance. Mean error of the Mag3300 magnetometer scalar was 795.5 nT. When combined with the wavelet package, the error was suppressed to −22.3, 3.3, and −0.4 nT using UKF, the two‐step algorithm, and GA, respectively. The results suggest an effective way for magnetometer calibration using GA and wavelet. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Multimodal Pedagogies for Teacher Education inTESOL
Authors: Yi Youngjoo , Angay‐Crowder Tuba
Published: December 2016

As a growing number of English language learners (ELLs) engage in digital and multimodal literacy practices in their daily lives, teachers are starting to incorporate multimodal approaches into their instruction. However, anecdotal and empirical evidence shows that teachers often feel unprepared for integrating such practices into their curricula (Coyle, Yañez, & Verdú, 2010; Sadik, 2008). This particular concern has led the authors of this essay to examine ways in which multimodal literacy practices can be integrated into teacher education for teaching English to speakers of other languages (TESOL). This Teaching Issues article describes how the first author designed and implemented two multimodal practices for preservice and in‐service teacher education programs in the United States. The essay highlights the challenges of incorporating multimodal practices into teacher education (e.g., epistemological issues, instructional challenges, and teachers’ resistance to multimodal practices). The authors offer suggestions for overcoming those challenges and propose future directions forTESOLteacher education and professional development.
Word Families and Frequency Bands in Vocabulary Tests: Challenging Conventions
Authors: Kremmel Benjamin
Published: December 2016

Vocabulary test development often appears to be based on the design principles of previous tests, without questioning or empirically examining the assumptions underlying those principles. Given the current proliferation of vocabulary tests, it seems timely for the field of vocabulary testing to problematize some of those traditionalised assumptions, based on more current research. This article begins this process by challenging two common assumptions key to vocabulary test development: (1) the counting unit of word families, and (2) the 1,000‐word band divisions in the use of frequency. Based on existing literature and an analysis of corpus‐based coverage figures, the article frames future research agendas by arguing that the lemma may be a more useful counting unit for vocabulary assessment and pedagogy. Further, it argues that the traditional 1,000‐item frequency bands are not optimal. Smaller 500‐item bands would be more informative at the higher frequencies, and bands larger than 1,000 items would be adequate at lower frequencies. Because most vocabulary tests are aimed at beginner to intermediate learners of English as a foreign language, these new empirically informed conventions should facilitate the development of more informative vocabulary tests.
Assessment of agricultural crops and natural vegetation in Scotland for energy production by anaerobic digestion and hydrothermal liquefaction
Authors: Biller Patrick , Lawson David , Madsen René B. , Becker Jacob , Iversen Bo B. , Glasius Marianne
Published: December 2016

The current paper investigates the use of natural vegetation and agricultural crops commonly found in Scotland as a source of bioenergy. Such biomass is shown to have a high moisture content upon harvest (∼80%) which renders them suitable for wet conversion technologies such as anaerobic digestion (AD) and hydrothermal liquefaction (HTL). Experimental investigations are carried out on 16 different types of biomass to assess their bio-crude yields via HTL and theoretical methane potential via AD based on compositional analysis. The different types of biomass vary significantly in biomass yield upon harvesting from 1.1 t/ha (dry matter) for bracken to a maximum of 17.5 t/ha for winter rye. These area specific yields are the most influential factor in the final energy yield per area. Area specific energy yields are found to average at 67 GJ/ha for AD and 53 GJ/ha for HTL. The respective conversion efficiencies of HTL and AD for different biomass feedstocks are also shown to be an important factor on the overall energy potential. AD averages a mass to energy conversion of 9.1 GJ/t compared to 7.2 GJ/t for HTL. A combination of AD and HTL is investigated by liquefying digestate from rye, but the results suggest this is not a viable option due to low bio-crude yields. However, analysis of the water phase post HTL allowed the calculation of theoretical methane potential from the HTL process water and suggests that this can yield additional energy. Overall, the work shows that utilisation of natural vegetation is a promising approach for bioenergy production.
Serious games and blended learning; effects on performance and motivation in medical education
Authors: Dankbaar Mary
Published: December 2016

Introduction More efficient, flexible training models are needed in medical education. Information technology offers the tools to design and develop effective and more efficient training. The aims of this thesis were: 1) Compare the effectiveness of blended versus classroom training for the acquisition of knowledge; 2) Investigate the effectiveness and critical design features of serious games for performance improvement and motivation.

Methods Five empirical studies were conducted to answer the research questions and a descriptive study on an evaluation framework to assess serious games was performed.

Results The results of the research studies indicated that: 1) For knowledge acquisition, blended learning is equally effective and attractive for learners as classroom learning; 2) A serious game with realistic, interactive cases improved complex cognitive skills for residents, with limited self-study time. Although the same game was motivating for inexperienced medical students and stimulated them to study longer, it did not improve their cognitive skills, compared with what they learned from an instructional e‑module. This indicates an ‘expertise reversal effect’, where a rich learning environment is effective for experts, but may be contra-productive for novices (interaction of prior knowledge and complexity of format).

Discussion A blended design is equally effective and attractive as classroom training. Blended learning facilitates adaptation to the learners’ knowledge level, flexibility in time and scalability of learning. Games may support skills learning, provided task complexity matches the learner’s competency level.
A novel maturation index based on neonatal diffusion tensor imaging reflects typical perinatal white matter development in humans
Authors: Rasmussen Jerod M. , Kruggel Frithjof , Gilmore John H. , Styner Martin , Entringer Sonja , Consing Kirsten N.Z. , Potkin Steven G. , Wadhwa Pathik D. , Buss Claudia
Published: December 2016

Human birth presents an abrupt transition from intrauterine to extrauterine life. Here we introduce a novel Maturation Index (MI) that considers the relative importance of gestational age at birth and postnatal age at scan in a General Linear Model. The MI is then applied to Diffusion Tensor Imaging (DTI) in newborns for characterizing typical white matter development in neonates. DTI was performed cross‐sectionally in 47 neonates (gestational age at birth = 39.1 ± 1.6 weeks [GA], postnatal age at scan = 25.5 ± 12.2 days [SA]). Radial diffusivity (RD), axial diffusivity (AD) and fractional anisotropy (FA) along 27 white matter fiber tracts were considered. The MI was used to characterize inflection in maturation at the time of birth using GLM estimated rates of change before and after birth. It is proposed that the sign (positive versus negative) of MI reflects the period of greatest maturation rate. Two general patterns emerged from the MI analysis. First, RD and AD (but not FA) had positive MI on average across the whole brain (average MIAD = 0.31 ± 0.42, average MIRD = 0.22 ± 0.34). Second, significant regions of negative MI in RD and FA (but not AD) were observed in the inferior corticospinal regions, areas known to myelinate early. Observations using the proposed method are consistent with proposed models of the white matter maturation process in which pre‐myelination is described by changes in AD and RD due to oligodendrocyte proliferation while true myelination is characterized by changes in RD and FA due to myelin formation.
Revisiting the law of the wake in wall turbulence
Authors: Krug Dominik , Philip Jimmy , Marusic Ivan
Published: December 2016

The streamwise mean velocity profile in a turbulent boundary layer is classically described as the sum of a log law extending all the way to the edge of the boundary layer and a wake function. While there is theoretical support for the log law, the wake function, defined as the deviation of the measured velocity profile from the log law, is essentially an empirical fit and has no real physical underpinning. Here, we present a new physically motivated formulation of the velocity profile in the outer region, and hence for the wake function. In our approach, the entire flow is represented by a two-state model consisting of an inertial self-similar region designated as ‘pure wall flow state’ (featuring a log-law velocity distribution) and a free stream state, which results in a jump in velocity at the interface separating the two. We show that the model provides excellent agreement with the available high Reynolds number mean velocity profiles if this interface is assumed to fluctuate randomly about a mean position with a Gaussian distribution. The new concept can also be extended to internal geometries in the same form, again confirmed by the data. Furthermore, adopting the same interface distribution in a two-state model for the streamwise turbulent intensities, with unchanged parameters, also yields a reliable and consistent prediction for the decline in the outer region of these profiles in all geometries considered. Finally, we discuss differences between our model interface and the turbulent/non-turbulent interface (TNTI) in turbulent boundary layers. We physically interpret the two-state model as lumping the effects of internal shear layers and the TNTI into a single discontinuity at the interface.
Optimal perturbation growth in axisymmetric intrusions
Authors: Sutherland Bruce R. , Caulfield C. P.
Published: December 2016

The cylindrical lock-release laboratory experiments of Sutherland & Nault (J. Fluid Mech., vol. 586, 2007, pp. 109–118) showed that a radially advancing symmetric intrusive gravity current spreads not as an expanding annulus (as is the case for bottom-propagating gravity currents), but rather predominantly along azimuthally periodic radial ‘spokes’. Here, we investigate whether the spokes are associated with azimuthal perturbations that undergo ‘optimal’ growth. We use a nonlinear axisymmetric numerical simulation initialised with the experimental parameters to compute the time-evolving axisymmetric base state of the collapsing lock fluid. Using fields from this rapidly evolving base state together with the linearised perturbation equations and their adjoint, the ‘direct–adjoint looping’ method is employed to identify, as a function of the azimuthal wavenumber $m$, the vertical–radial structure of the set of initial perturbations that exhibit the largest total perturbation energy gain over a target time $T$. Of this set of perturbations, the one that extracts energy fastest, and so is expected to be observed to emerge first from the base flow, has azimuthal wavenumber comparable to the number of spokes observed in the experiment.
A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow
Authors: SKILES S. McKENZIE , PAINTER THOMAS , OKIN GREGORY S.
Published: December 2016

Dust deposition to snow can have regionally important climatic and hydrologic impacts resulting from direct reduction of surface albedo and indirectly from the initiation of snow albedo feedbacks. Modeling the radiative impacts of dust deposited in snow requires knowledge of the optical properties of both components. Here we present an inversion technique to retrieve the effective optical properties of dust deposited in mountain snow cover from measurements of hemispherical dust reflectance and particle size distributions using radiative transfer modeling. First, modeled reflectance is produced from single scattering properties modeled with Mie theory for a specified grain size distribution over a range of values for the imaginary part of the complex refractive index (k = 0.00001–0.1). Then, a multi-step look-up table process is employed to retrieve kλ and single scattering optical properties by matching measured to modeled reflectance across the shortwave and near infrared. The real part of the complex refractive index, n, for dust aerosols ranges between 1.5 and 1.6 and a sensitivity analysis shows the method is relatively insensitive to the choice of n within this range, 1.525 was used here. Using the values retrieved by this method to update dust optical properties in a snow + aerosol radiative transfer model reduces errors in springtime albedo modeling by 50–70%.
Both high and low plasma levels of 25-hydroxy vitamin D increase blood pressure in a normal rat model
Authors: Mirhosseini Naghmeh Z. , Knaus Steven J. , Bohaychuk Kaylee , Singh Jaswant , Vatanparast Hassan A. , Weber Lynn P.
Published: December 2016

The lower threshold plasma 25-hydroxy vitamin D (25(OH)D) level for optimal cardiovascular health is unclear, whereas the toxicity threshold is less clear. The aim of this study was to examine the cardiovascular–vitamin D dose–response curve in a normal rat model. Doses of cholecalciferol ranged from deficiency to toxic levels (equivalent to human doses of 0, 0·015, 0·25 and 3·75mg/d) for 4 weeks, and then cardiovascular health was examined using blood pressure telemetry and high-resolution ultrasound in normal male rats (n 16/group, 64 rats total). After 1 month, only the 0·25mg/d group had plasma 25(OH)D that was within current recommended range (100–125 nmol/l), and all groups failed to change plasma Ca or phosphate. Systolic blood pressure increased significantly (10–15 mmHg) in the rat groups with plasma 25(OH)D levels at both 30 and 561 nmol/l (groups fed 0 and 3·75mg/d) compared with the group fed the equivalent to 0·015mg/d (43 nmol/l 25(OH)D). Although not significant, the group fed the equivalent to 0·25mg/d (108 nmol/l 25(OH)D) also showed a 10 mmHg increase in systolic blood pressure. Carotid artery diameter was significantly smaller and wall thickness was larger, leading to higher peak carotid systolic blood velocity in these two groups. Despite these vascular changes, cardiac function did not differ among treatment groups. The key finding in this study is that arterial stiffness and systolic blood pressure both showed a U-shaped dose–response for vitamin D, with lowest values (best cardiovascular health) observed when plasma 25(OH)D levels were 43 nmol/l in normal male rats.
The Procedure of Demosthenes’ Against Leptines: How to Repeal (And Replace) an Existing Law
Authors: Canevaro Mirko
Published: December 2016

The article offers a novel interpretation of the procedure followed in the case of Demosthenes’ speech Against Leptines, clarifying the workings of the institutions that secured the coherence of the laws of Athens. The procedure of this case of γραϕὴ νόμον μὴ ἐπιτήδειον θεῖναι seems idiosyncratic: the case came to court over a year after the enactment of the law of Leptines, so Leptines was no longer liable to punishment and the action was only against the law itself; it also involved the proposal of a replacement law. Scholars have argued either that the θεσμοθέται devised a special procedure for these circumstances or that Demosthenes deceived the judges into believing they could enact the replacement law. I argue that there existed two regular uses of the γραϕὴ νόμον μὴ ἐπιτήδειον θεῖναι: (1) to repeal laws that had been enacted irregularly and punish the proposer; (2) as part of nomothesia, to repeal existing laws that contradicted the new bill. This second use is the one that we find in Against Leptines: Demosthenes attempts to repeal Leptines’ law as part of the procedure to enact the replacement law. If the accusation is successful, he pledges to have the new bill enacted by the νομοθέται.
Οὔκ ἐστι Σαπϕοῦς τοῦτο τὸ ᾆσμα: Variants of Sappho's Songs in Athenaeus’ Deipnosophistae
Authors: Kreij Mark de
Published: December 2016

Sappho and her songs became popular throughout the Greek world very soon after her death, as reflected on Attic vases, in comedies and in the many references to her songs by authors of all times. One important source for her songs, especially before the discovery of the papyri at Oxyrhynchus and elsewhere, is Athenaeus’ Deipnosophistae. This article presents a close analysis of three fragments of Sappho that were transmitted within this work, in order to establish the form of the fragments as they were incorporated by Athenaeus. Divergence from Sappho's original need not be the result of scribal error, but may represent a variation born in performance or active reception of the poems by Athenaeus or his source. Furthermore, the fragments demonstrate that it is insufficient to describe Athenaeus’ engagement with the Lesbian dialect as atticizing. By extension, the idiosyncracies of his quotations of Sappho's songs should be reflected in editions of the Deipnosophistae.
How to Control the Present: A Unified Account of the Nonpast Uses of the Aorist Indicative
Authors: Nijk Arjan
Published: December 2016

This article addresses the asymmetry between the two main aspectual paradigms in the Classical Greek verbal system: the imperfective and the aorist (perfective). Whereas the imperfective has separate indicative forms for present and past time reference, i.e. the ‘primary’ and the ‘secondary’ indicative, the aorist only has a secondary (‘past’) indicative. I argue that this asymmetry is not only morphological but also semantic. That is, while the secondary imperfective indicative (the ‘imperfect’) is confined to past time reference, the secondary aorist indicative is used not only to refer to the past but also to the present. It then enters into aspectual competition with the primary imperfective indicative (the ‘present’). Based on R.W. Langacker's (2011) Cognitive Grammar account of aspect, I distinguish five types of context in which a present tense form with perfective aspect is a desideratum, and argue that here the secondary aorist indicative is used to fulfil this function. Moreover, I present a diachronic account of the origin of this remarkable asymmetry, arguing that the aorist indicative was never a past tense to begin with.
Counting the Past in Herodotus’ Histories
Authors: Sergueenkova Valeria
Published: December 2016

This paper explores instances in Herodotus’ Histories where the historian or his characters engage with very large numbers by counting vast collections of people or things, establishing the dimensions of huge objects and measuring long stretches of time. In these episodes, Herodotus explores how quantifying the material traces of the past can help reconstruct antiquity. This methodological point is most evident in his calculations in book 2, and this paper focuses in particular on his persistent reckoning in three interrelated Egyptian accounts: those of the nature of the Nile valley, of the construction of the pyramids and of the genealogy of the Theban priests. I argue that Herodotus’ quantifying efforts, far from being only a rhetorical strategy to increase the narrator's credibility and authority, are an important, indeed crucial, part of his historical method.
When morality policies meet governance: private governance as response to value-driven conflicts
Authors: Euchner Eva-Maria , Preidel Caroline
Published: December 2016

Scholars of morality policy change primarily analyse state regulation. Through this narrow focus, they ignore private actors and their varying engagement across time and policies. We contribute to this research gap by comparing and explaining private actors’ involvement in euthanasia and prostitution policy in Germany. We argue that the extent of private engagement is determined by the private actors’ capacity to govern, governmental decision-making barriers and private actors’ interests. Thus, the present study makes an empirical contribution to the literature on private governance by exploring largely disregarded policy issues that are least-likely cases for the delegation of public regulatory competence. Furthermore, it adds to the morality policy literature in a theoretical way by showing that policy change in this field is not only a question of scope, timing and direction but also one of the types of governing actors.
Competition in local land use planning?
Authors: Berli Jan
Published: December 2016

The extent of political fragmentation of metropolitan areas impedes effective land use planning in many countries, and thus contributes to the phenomenon of urban sprawl. For some metropolises in the United States and Europe, strategic interaction between local policymakers codetermines the implementation of local planning policies. However, previous empirical analyses of this phenomenon have usually assumed interdependence in planning decisions to be confined to neighbouring jurisdictions. This is a common simplification in research on diffusion in public policies. Proceeding on the assumption that municipal zoning decisions are subject to competition between municipal authorities trying to attract new residents, I suggest an alternative conceptualisation of location-choice competition in Tiebout-like economies: the correlations of out-commuting patterns serve as a proxy for the degree to which municipalities are competitors for mobile residents, irrespective of their contiguity. Spatial autoregressive models, estimated on the basis of a large panel of fine-grained zoning data, reveal that zoning decisions in the Canton of Zurich, Switzerland’s most dynamic metropolitan area, are indeed subject to such interdependence.
Is the post- in post-identity the post- in post-genre?
Authors: James Robin
Published: December 2016

The ‘post-’ in both post-identity politics and post-genre musical practice refers to the same thing. Through readings of Taylor Swift's ‘Shake It Off’, Diplo's description of his practice as a DJ, producer and impresario, Sasha Frere-Jones's infamousNew Yorkerpiece on indie rock miscegenation, and critical race theorists Cristina Beltran and Jared Sexton's critiques of post-racial politics, I demonstrate that progress past traditional commitments to white racial purity is both the defining characteristic of post-racial whiteness, and what makes multigenre pop practice count as post-genre. The ‘post-’ in post-identityis what distinguishes post-genre practice from supposedly more primitive forms of genre transgression, such as the love & theft-style cultural appropriation Eric Lott identifies in 19th century blackface minstrelsy or Pitbull's Latin American style racial/musical mestizaje.
Dancefloor-driven literature: subcultural big bangs and a new center for the aesthetic universe
Authors: Morrison Simon A.
Published: December 2016

This paper sets coordinates squarely for Holleran's ‘aesthetic center of the universe’ – venturing towards the black hole of the nightclub dancefloor. Further, it will investigate those writers determined to capture the electronic essence of this at times alien dance music culture within the rather more earth-bound parameters of the written word. How might such authors write about something so otherworldly as the nightclub scene? How might they write lucidly and fluidly about the rigid, metronomic beat of electronic music? What literary techniques might they deploy to accurately recount in fixed symbols the drifting, hallucinatory effects of a drug experience? In an attempt to address these questions this paper will offer an altogether outerspace overview of this subculture and its fictional literary output.
Joint Activity in the Maritime Traffic System: Perceptions of Ship Masters, Maritime Pilots, Tug Masters, and Vessel Traffic Service Operators
Authors: Mansson Joakim Trygg , Lutzhoft Margareta , Brooks Ben
Published: December 2016

Teamwork in the maritime traffic system has been identified as an area of concern, and reports suggest there is room for improvement. Such improvements should be based on an understanding of how everyday activities are performed. This study was therefore aimed at gaining an insight into the everyday activity of navigating and manoeuvring ships in port waters. To get such an insight, the perceptions of ship masters, maritime pilots, tug masters and Vessel Traffic Service operators active in Australia were probed through qualitative research interviews. A conceptual framework based on Clark's work on joint activity was used to guide the study. Results indicate that in order to get the job done, these maritime professionals employ tools and procedures beyond those intended to be used, vary their level of participation, assume roles which differ from those prescribed, sometimes base their assumptions and expectations on poor quality evidence, and occasionally avoid communication. While such adaptations may be necessary to get the job done, they also reduce the participants’ ability to establish common ground – which is essential for coordination.
Corporations before International Criminal Courts: Implications for the International Criminal Justice Project
Authors: KYRIAKAKIS JOANNA
Published: December 2016

The debate over whether the International Criminal Court should have jurisdiction over corporations has persisted over the years, despite the failure of the legal persons proposals at Rome. For its part, the Special Tribunal for Lebanon determined that it has jurisdiction over corporations for the purpose of crimes against the administration of the Tribunal, albeit not for the substantive crimes over which it adjudicates. Most recently, the African Union has adopted a Protocol that, should it come into operation, would create a new international criminal law section of the African Court of Justice and Human and People's Rights with jurisdiction over corporations committing or complicit in serious crimes impacting Africa. In light of the enduring nature of the proposal that international criminal institutions should directly engage with the problem of commercial corporations implicated in atrocity, this article explores the possible implications for the international criminal justice project were its institutions empowered to address corporate defendants and prosecutors emboldened to pursue cases against them. Drawing on the expressive goals of international criminal justice and concepts of sociological legitimacy, as well as insights from Third World Approaches to International Law, the article suggests that corporate prosecutions, where appropriate, may have a redeeming effect upon the esteem in which some constituent audiences hold international criminal law, as a system of global justice. The article's thesis is then qualified by cautionary thoughts on the redemptive potential of corporate prosecutions.