Interaction of nonionic polymers at a clay interface

The structure and dynamics at the interface of swelling clays (smectites) are crucial to such diverse applications as drilling for oil, cosmetics, paints, water treatment, or chemical reactions. From our previous NMR studies on clay suspensions, we have shown how the orientation of interfacial molecules is affected by the clay structure1, by the nature of counterions 2, or by the composition of the liquid phase3. These results have been mainly obtained from the analysis of residual quadrupolar splittings of nuclei from interfacial species. In this work, we report our studies on a clay montmorillonite suspended in aqueous solutions of non ionic polymers. The polymer perturbs the structure within the interfacial region as deduced from the variations of the splittings of water quadrupolar nuclei and of sodium-23 relaxation parameters in terms of the polymer concentration. Proton self-diffusion coefficients and carbon-13 relaxation times are measured to describe the influence of the clay on the polymer mobility. The dependence of the polymer nature on these parameters is also investigated.     

Ultrasonic evaluation of geometrical and surface parameters of rough defects in solids

Ultrasonic measurements from rough cracks were carried out using both broad-band and narrow-band methods. An analysis is suggested to determine parameters of the crack quantitatively such as size, shape, rms surface roughness, and distribution function of the surface roughness. Ultrasonic measurements of the parameters compare very well with the actual parameters of the defect.     

Zur Berechnung von Wirbelkernhalbmessern in rotationssymmetrischen Drallströmungen

Zusammenfassung Drei der bedeutendsten Verfahren zum Berechnen des Wirbelkernhalbmessers in rotationssymmetrischen Drallstr?mungen werden miteinander verglichen. Zwar liegt jedem dieser Verfahren eine Energieberechnung zugrunde; die Ergebnisse unterscheiden sich jedoch erheblich voneinander. Es wird die Ursache jener Abweichungen untersucht und festgestellt, da? das von K. Bammert vorgeschlagene Verfahren nur mit Berücksichtigung der Volumflu?verteilung die gleichen Ergebnisse wie die Berechnungsverfahren von E. Meldau und M. Strscheletzky liefert. Ferner geht aus der Untersuchung die Bedeutung der Axialgeschwindigkeitsverteilung hervor. Die Verwendbarkeit dieser Verfahren bleibt dadurch auf jene F?lle beschr?nkt, in denen der Drall und die Axialgeschwindigkeit in der betrachteten achsnormalen Ebene konstant sind.     

Automated effect-specific mammographic pattern measures

We investigate the possibility to develop methodologies for assessing effect specific structural changes of the breast tissue using a general statistical machine learning framework. We present an approach of obtaining objective mammographic pattern measures quantifying a specific biological effect, such as hormone replacement therapy (HRT). We compare results using this approach to using standard density measures. We show that the proposed method can quantify both age related effects and effects caused by HRT. Age effects are significantly detected by our method where standard methodologies fail. The separation of HRT subpopulations using our approach is comparable to the best methodology, which is interactive.      

Compact spectrum splitting photovoltaic module with high efficiency

We have designed, fabricated, and tested a small, integrated photovoltaic module comprised of two separately‐contacted, high efficiency, multijunction solar cells and non‐imaging optics that both concentrate and spectrally split the incoming light. This hybrid design allows us to individually optimize the tandem cells and optical elements. The system has a measured module efficiency, including optical and packaging losses but not power combination losses, of 38.5 ± 1.9% under the AM1.5 direct terrestrial spectrum. The internal optics concentrate the light by a factor of approximately 20. We find excellent agreement between the modeled and measured performance. This is the highest confirmed conversion efficiency demonstrated for a photovoltaic module. Copyright © 2010 John Wiley & Sons, Ltd.     

Decoherence dynamics estimation for superconducting gate-model quantum computers

Quantum Information Processing - In this note, I attempt to explore the quantum Colonel Blotto game and contrast it with the classical Colonel Blotto game; in particular, I will focus on an...     

State stabilization for gate-model quantum computers

Quantum Information Processing - Historically, the information efficiency of the secret key in quantum key distribution (QKD) schemes based on binary signal formats was limited to 1 bit/particle....     

Pulsed laser reshaping and fragmentation of upconversion nanoparticles — from hexagonal prisms to 1D nanorods through “Medusa”-like structures

One dimensional (1D) nanostructures attract considerable attention, enabling a broad application owing to their unique properties. However, the precise mechanism of 1D morphology attainment remains a matter of debate. In this study, ultrafast picosecond (ps) laser-induced treatment on upconversion nanoparticles (UCNPs) is offered as a tool for 1D-nanostructures formation. Fragmentation, reshaping through recrystallization process and bioadaptation of initially hydrophobic (β-Na_1.5Y_1.5F₆: Yb³⁺, Tm³⁺/β-Na_1.5Y_1.5F₆) core/shell nanoparticles by means of one-step laser treatment in water are demonstrated. “True” 1D nanostructures through “Medusa”-like structures can be obtained, maintaining anti-Stokes luminescence functionalities. A matter of the one-dimensional UCNPs based on direction of energy migration processes is debated. The proposed laser treatment approach is suitable for fast UCNP surface modification and nano-to-nano transformation, that open unique opportunities to expand UCNP applications in industry and biomedicine.

     

Determination the efficiency of open mixing screws

Our goal is the determination of the material flow processes around the mixing screws and introducing a new mixing index which can characterize the perform