Polyamide-rubber blends: micrscopic studies of the deformation zone

The morphology of injection moulded samples of polyamide—polybutadiene blends (85.15) with an average particle size of 0.3 μm was studied. The samples were fractured in a notched tensile test at crosshead speeds of 10−4 and 1 ms −1 and the structure of the deformation zone was studied using various techniques: polarized light microscopy, scanning electron microscopy, transmission electron microscopy on stained cut samples and carbon replicas, and selected area electron diffraction transmission electron microscopy. The deformation zone of samples tested at 10−4 ms−1 was found to consist of two layers. Far from the fracture surface a layer was observed with more or less round cavities and with cavities in the rubber particles, while near the fracture surface a layer with strongly deformed cavities (length/diameter ratio of 5–10) could be seen. In the samples tested at 1 ms−1 the deformation zone was found to have three layers. In addition to the two previous layers an extra layer next to the fracture plane was found. This layer was 2–3 μm thick with round rubber particles and no orientation of the matrix material. This indicates that, at the high deformation speed of the test, relaxation in the melt took place, suggesting that the material around the crack tip was molten during fracture.\u

A hybrid approach to space power control

Conventional control systems have traditionally been utilized for space-based power designs. However, the use of expert systems is becoming important for NASA applications. Rocketdyne has been pursuing the development of expert systems to aid and enhance control designs of space-based power systems. The need for integrated expert systems is vital for the development of autonomous power systems

Chasing consistency: an update of the TCP gene family of Malus × domestica

The 52 members of the Teosinte-Branched 1/Cycloidea/Proliferating Cell Factors (TCP) Transcription Factor gene family in Malus × domestica (M. × domestica) were identified in 2014 on the first genome assembly, which was released in 2010. In 2017, a higher quality genome assembly for apple was released and is now considered to be the reference genome. Moreover, as in several other species, the identified TCP genes were named based on the relative position of the genes on the chromosomes. The present work consists of an update of the TCP gene family based on the latest genome assembly of M. × domestica. Compared to the previous classification, the number of TCP genes decreased from 52 to 40 as a result of the addition of three sequences and the deduction of 15. An analysis of the intragenic identity led to the identification of 15 pairs of orthologs, shedding light on the forces that shaped the evolution of this gene family. Furthermore, a revised nomenclature system is proposed that is based both on the intragenic identity and the homology with Arabidopsis thaliana (A. thaliana) TCPs in an effort to set a common standard for the TCP classification that will facilitate any future interspecific analysi

Summing free unitary random matrices

I use quaternion free probability calculus - an extension of free probability to non-Hermitian matrices (which is introduced in a succinct but self-contained way) - to derive in the large-size limit the mean densities of the eigenvalues and singular values of sums of independent unitary random matrices, weighted by complex numbers. In the case of CUE summands, I write them in terms of two "master equations," which I then solve and numerically test in four specific cases. I conjecture a finite-size extension of these results, exploiting the complementary error function. I prove a central limit theorem, and its first sub-leading correction, for independent identically-distributed zero-drift unitary random matrices.Comment: 17 pages, 15 figure

Antireflective photonic structure for coherent nonlinear spectroscopy of single magnetic quantum dots

This work presents epitaxial growth and optical spectroscopy of CdTe quantum dots (QDs) in (Cd,Zn,Mg)Te barriers placed on the top of (Cd,Zn,Mg)Te distributed Bragg reflector. The formed photonic mode in our half-cavity structure permits to enhance the local excitation intensity and extraction efficiency of the QD photoluminescence, while suppressing the reflectance within the spectral range covering the QD transitions. This allows to perform coherent, nonlinear, resonant spectroscopy of individual QDs. The coherence dynamics of a charged exciton is measured via four-wave mixing, with the estimated dephasing time $T_2=(210\,\pm\,40)$ ps. The same structure contains QDs doped with single Mn$^{2+}$ ions, as detected in photoluminescence spectra. Our work therefore paves the way toward investigating and controlling an exciton coherence coupled, via $s$,$p$-$d$ exchange interaction, with an individual spin of a magnetic dopant.Comment: 6 pages, 5 figure

Cervical cancer mortality in young adult European women

Background: The process of social, political and economic transformation, which took place in Central and Eastern Europe in the early 90's, has affected many spheres of Europeans' lives, including health-associated issues. These changes also had an impact on mortality rates due to cervical cancer (CC). Therefore, the aim of this study was to analyse CC mortality trends in Europe after 1990. Methods: Data on death due to CC, uterine cancers and unspecified uterine cancers, in women aged 20\u201344, were taken from the WHO Mortality Database. Trends in European countries between 1990 and 2017 were assessed using the Joinpoint Regression Program. Results: Most of the countries experienced a decrease in CC mortality. Although the lowest rates were observed in EU15 Member States, the highest decreases were observed in Central and Eastern Europe. However, there are still differences in mortality in these countries. There are also a few countries like Belarus, Latvia and Ukraine, which experienced an increase in mortality. The range of mortality across Europe in 2017 was between 0.6 and 5.2/100,000 women. Conclusions: It is essential to introduce well-organised screening programmes for early detection of CC with coverage of a correspondingly high percentage of the population, particularly in East-Central Europe, as well as to introduce high-coverage HPV vaccination in all European countries

The temperature and entropy of CFT on time-dependent backgrounds

We express the AdS-Schwarzschild black-hole configuration in coordinates such that the boundary metric is of the FLRW type. We review how this construction can be used in order to calculate the stress-energy tensor of the dual CFT on the FLRW background. We deduce the temperature and entropy of the CFT, which are related to the temperature and entropy of the black hole. We find that the entropy is proportional to the area of an apparent horizon, different from the black-hole event horizon. For a dS boundary we reproduce correctly the intrinsic temperature of dS space.Comment: 19 pages, major revision, several comments added, version to appear in JHE

Universal eigenvector statistics in a quantum scattering ensemble

We calculate eigenvector statistics in an ensemble of non-Hermitian matrices describing open quantum systems [F. Haake et al., Z. Phys. B 88, 359 (1992)] in the limit of large matrix size. We show that ensemble-averaged eigenvector correlations corresponding to eigenvalues in the center of the support of the density of states in the complex plane are described by an expression recently derived for Ginibre's ensemble of random non-Hermitian matrices.Comment: 4 pages, 5 figure

Accelerated anti-Markovnikov alkene hydrosilylation with humic-acid-supported electron deficient platinum single atoms

Hydrosilylation reaction is one of the largest-scale applications of homogeneous catalysis, and Pt homogeneous catalyst has been widely used in this reaction for the commercial manufacture of silicon products. However, homogeneous Pt catalysts results in considerable problems, such as undesired side reactions, unacceptable catalyst residues and disposable platinum consumption. Here, we synthesized electron deficient Pt single atoms supported on humic matter (Pt1@AHA\_U\_400), and the catalyst was used in hydrosilylation reaction, which showed super activity (turnover frequency as high as 3.0 × 107 h-1) and selectivity (>99%). Density functional theory calculations reveal that the high performance of the catalyst results from the atomic dispersion of Pt and the electron deficiency of the Pt1 atoms, which is different from conventional Pt nanoscale catalysts. Excellent performance is maintained during recycle experiments, indicating the high stability of the catalyst