Measurements of superfluid densities and critical superfluid mass currents of pure 4He and 3He/4He mixtures in nuclepore near the lambda transition

Measurements have been made of the relative superfluid density _sp/ and the critical mass current I _sc for the onset of dissipation in the superfluid flow of pure ⁴He and ³He/⁴He mixtures in the circular cylindrical pores of Nuclepore near the transition, using a double-ended Helmholtz resonator. Pore diameters of 0.03, 0.1, and 0.4 m were studied using ³He mole fractions of 0.0,0.2, and 0.4. For each pore diameter d _p and mole fraction x our results for _sp / were fitted relatively well by the form C(t – t ₀₁)^0.675 and those for I _sc by the form I _sc0(t–t _0c ) ^g , where t [T –T]/T . For each combination of d _p and x the reduced onset temperatures t ₀₁ and t _0c are in rough agreement with each other but somewhat larger than values found by others for Nuclepore. For the smaller two pore diameters, these onset temperatures are consistent with the universality hypothesis that near T, ² _sb /m ₄ ² k _B T should be a constant independent of T and x. Here is the reduced Planck constant, _sb is the bulk superfluid density, is the coherence length, m ₄ is the ⁴He atom mass, k _B is Boltzmann's constant, and T is the absolute temperature. At each value of x the amplitudes C agree well with the corresponding amplitude for _sb /, and g equals 1.17 ± 0.04 for all cases. Measurements of the velocity of second sound at x = 0.000, 0.190, 0.401, and 0.450 are also reported.Work supported by U.S. Department of Energy contract EY-76-S-02-1569.     

Material and bonding characteristics for dimensioning and modelling of textile reinforced concrete (TRC) elements

The collaborative research center “Textile Reinforced Concrete (TRC) – Development of a New Technology” (SFB 532) established at Aachen University (RWTH Aachen) is investigating the basic mechanisms of this new composite material. The use of technical textiles as reinforcement material in cementitious binder systems allows the production of thin-structured elements as will be dimensioned, modelled, and produced within the research project. For this reason the material properties of the single components have to be known and will be integrated in analytical and numerical simulations of textile reinforced structures. Thus key parameters on the meso-level are introduced. These are on the one hand the tensile strength and elastic modulus of filaments and rovings, on the other hand mechanical and fracture mechanical parameters of the matrix, and finally the bonding characteristics of filaments as well as rovings embedded in the cement based matrix.     

Low Loss Star Coupler Concept for AWGs in Rib Waveguide Technology

We introduce a new concept for a tapered transition between waveguides and a free propagation region (FPR) for rib waveguide technology. The optical field is pressed downwards to the lower part of the guiding layer by tapering off the waveguide. The subsequent FPR is also etched down to the lower part of the guiding layer, which results in an adiabatic transition from the waveguide to the slab. Arrayed waveguide gratings, designed with this technique, were fabricated in silicon-on-insulator and showed a reduction in insertion loss of about 2.5 dB     

Measuring Affective Clarity Indirectly: Individual Differences in Response Latencies of State.

This research investigated a new method to measure momentary affective clarity indirectly, which is based on latencies of responses to state affect items. Three studies revealed that this indirect measure of momentary clarity demonstrated high reliability and stability as well as convergent and predictive validity. The indirect measure was associated with dispositional clarity when the concept of clarity was activated before measuring response latencies (Studies 1 and 2) and was related to self-reports of momentary clarity (Study 3). Furthermore, Study 3 demonstrated that indirectly measured clarity decreased after an affectively complex film. Indirectly, but not directly, measured momentary clarity predicted a more positive affective state at the end of the study. This effect was mediated by affect regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An AMR sensor-based measurement system for magnetoelectrical resistivity tomography

A magnetoelectrical resistivity measurement system is proposed, which combines measurement of the electric potential and the magnetic field due to a current injection into a sample. Measurement of the electric potential, as well as the injected current, is similar to traditional electrical resistivity tomography (ERT) data acquisition. For the magnetic field measurements, 24 sensor modules have been developed using three component anisotropic magnetoresistive (AMR) sensors, mounted on a vertically moving scanning torus. The system is designed to operate in a typical laboratory magnetic noise environment without extensive shielding. To compensate for the effects of the Earth's magnetic field, the AMR sensors are operated with a field feedback circuit. Optimal noise reduction is provided by the use of a lock-in frequency of 25 Hz, with sine wave modulation and measurement cycles of 10 s. The resolution of the system is better then 50 pT and the aimed accuracy is 0.1%. The system provides a data set of magnetic fields complimentary to traditional ERT to determine the internal conductivity distribution of cylindrical samples with the dimension of 0.1-m radius and 0.5-m height.     

MICAST — The effect of magnetically controlled fluid flow on microstructure evolution in cast technical Al-alloys

The MICAST research program focuses on a systematic analysis of the effect of convection on the microstructure evolution in cast Al-alloys. The experiments within MICAST are carried out under well defined thermally and magnetically controlled, convective boundary conditions and analyzed using advanced diagnostics and theoretical modeling, involving phase field simulation, micro-modeling and global simulation of heat and mass transport. The MICAST team uses as a model material the Al-Si base alloys. This paper gives a brief overview on recent experimental results of the MICAST team on the effect of rotating magnetic fields on microstructure in AlSi alloys.     

The universal remote console: a universal access bus for pervasive computing

V2, a technical committee of the International Committee for information technology standards is developing standards for information technology access interfaces. As part of this endeavor, V2 is to issue the Universal Remote Console architecture, a set of draft standards for public review and comment. The five standards specify communications between a Target - a device or service the user wishes to access and a universal remote console-software that is typically hosted on a user's personal device. The standards specify mechanisms for the discovery, selection, configuration, and operation of user interfaces and its options.     

Simultaneous reconstruction of evolutionary history and epidemiological dynamics from viral sequences with the birth–death SIR model

The evolution of RNA viruses, such as human immunodeficiency virus (HIV), hepatitis C virus and influenza virus, occurs so rapidly that the viruses'' genomes contain information on past ecological dynamics. Hence, we develop a phylodynamic method that enables the joint estimation of epidemiological parameters and phylogenetic history. Based on a compartmental susceptible–infected–removed (SIR) model, this method provides separate information on incidence and prevalence of infections. Detailed information on the interaction of host population dynamics and evolutionary history can inform decisions on how to contain or entirely avoid disease outbreaks. We apply our birth–death SIR method to two viral datasets. First, five HIV type 1 clusters sampled in the UK between 1999 and 2003 are analysed. The estimated basic reproduction ratios range from 1.9 to 3.2 among the clusters. All clusters show a decline in the growth rate of the local epidemic in the middle or end of the 1990s. The analysis of a hepatitis C virus genotype 2c dataset shows that the local epidemic in the Córdoban city Cruz del Eje originated around 1906 (median), coinciding with an immigration wave from Europe to central Argentina that dates from 1880 to 1920. The estimated time of epidemic peak is around 1970.     

Functionalizable composite nanoparticles as a dual magnetic resonance imaging/computed tomography contrast agent for medical imaging

A dual contrast agent for computed tomography (CT) and magnetic resonance imaging (MRI) was synthesized via microemulsion polymerization. This contrast agent consists of Fe₃O₄ particles (d = 7 nm) with an iodine-carrying nanopolymeric shell, with overall particle sizes ranging from 50 to 250 nm. 2-Methacryloyloxyethyl(2,3,5-triiodobenzoate) was used as the monomer. Sodium oleate was used as the surfactant and its amount was varied to control the overall particle size. The composite nanoparticles were mainly characterized via dynamic light scattering, with further analyses using transmission electron microscopy and atomic force microscopy. The particles provided a highly visible contrast in CT and MR images. A template for biomedical applications was created by adding a comonomer and the particles were further functionalized with the somatostatin analogue Tyr³-octreotate. The particles were tested for specific uptake into somatostatin receptor-positive AR42J cells. The additional uptake of the functionalized particles was investigated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47571.