We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain ( ${\sim}2.8\,\mbox{K Jy}^{-1}$ ) low-system temperature ( ${\sim}18\,\mbox{K at }20\,\mbox{cm}$ ) radio array that currently operates at 580–1 670 MHz and can produce tied-array beams suitable for pulsar observations. This paper presents results from the MeerTime Large Survey Project and commissioning tests with PTUSE. Highlights include observations of the double pulsar $\mbox{J}0737{-}3039\mbox{A}$ , pulse profiles from 34 millisecond pulsars (MSPs) from a single 2.5-h observation of the Globular cluster Terzan 5, the rotation measure of Ter5O, a 420-sigma giant pulse from the Large Magellanic Cloud pulsar PSR $\mbox{J}0540{-}6919$ , and nulling identified in the slow pulsar PSR J0633–2015. One of the key design specifications for MeerKAT was absolute timing errors of less than 5 ns using their novel precise time system. Our timing of two bright MSPs confirm that MeerKAT delivers exceptional timing. PSR $\mbox{J}2241{-}5236$ exhibits a jitter limit of $<4\,\mbox{ns h}^{-1}$ whilst timing of PSR $\mbox{J}1909{-}3744$ over almost 11 months yields an rms residual of 66 ns with only 4 min integrations. Our results confirm that the MeerKAT is an exceptional pulsar telescope. The array can be split into four separate sub-arrays to time over 1 000 pulsars per day and the future deployment of S-band (1 750–3 500 MHz) receivers will further enhance its capabilities.

Until the end of 1926 it was not known that Pseudococcus gahani, Green, occurred in South Africa. That it had not been recognised before is perhaps due mainly to the fact that very frequently it is found in association with P. maritimus, Erhorn, and was thus regarded as a form of the latter species. It may be noted here that P. capensis, Brain (Ann. Ent. Soc. Amer., v, p. 182, 1912) is a synonym of P. maritimus, Erhorn, as previously recorded in “Farming in South Africa” (i, pt. 2, p. 64, May 1926).

Measurements of the distributions of pressure on a bluff flat plate (fence) have been correlated with the characteristics of the smooth-wall boundary layer in which it is immersed. For zero pressure-gradient flows, correlations are obtained for the variation of form drag with plate height h which are analogous in form to the ‘law of the wall’ and the ‘velocity-defect law’ for the boundary-layer velocity profile. The data for adverse pressure-gradient flows is suggestive of a ‘law of the wake’ type correlation. Pressures on the upstream face of the bluff-plate are determined by a wall-similarity law, even for h/δ > 1, and are independent of the pressure-gradient history of the flow; the separation induced upstream is apparently of the Stratford-Townsend type. The effects of the history of the boundary layer are manifested only in the flow in the rear separation bubble, and then only for h/δ > ½. The base pressure is also sensitive to free-stream pressure gradients downstream of the bluff-plate. The relative extent of upstream influence of the bluff-plate on the boundary layer is found to increase rapidly as h/δ decreases. One set of measurements of the mean flow field is also presented.

This paper describes a floating-element skin friction meter which has been designed for use in adverse pressure gradients. The effects of secondary forces on the element, which arise from the pressure gradient, are examined in some detail. The limitations of various methods of measuring wall shear stress are discussed and the results from the floating element device are compared with measurements taken in a two-dimensional boundary layer using Preston tubes and velocity profiles. As it is planned to use the instrument later for direct measurements of the shear stress in three-dimensional boundary layers, the relevance of the instrument to this situation is also discussed.

Les effets radio-induits sur le pancréas, communément décrits chez les mammifères, concernent essentiellement des modifications structurales observées à long terme. En revanche, peu d'études traitent des conséquences fonctionnelles d'une irradiation sur le pancréas exocrine. Le but de ce travail est de suivre les effets aigus d'une irradiation corps entier sur le volume et l'activité enzymatique du suc pancréatique. Une irradiation gamma corps entier à la dose de 6 Gy a été réalisée chez des porcs. Une collecte de suc pancréatique, par cathétérisme permanent du canal pancréatique, a été réalisée avant et après exposition avec mesure en continu du volume sécrété. Sur chaque échantillon de suc pancréatique, la concentration protéique ainsi que l'activité enzymatique de la trypsine, chymotrypsine, élastase, lipase et amylase ont été déterminées. Le volume de suc pancréatique sécrété quotidiennement diminue dès le lendemain de l'irradiation et le niveau sécrétoire ne revient jamais à des valeurs enregistrées avant irradiation. La quantité de protéines et les activités totales des enzymes sécrétées dans le suc pancréatique sont réduites de manière parallèle. Enfin, seules les activités spécifiques de l'élastase et de la lipase sont modifiées après l'irradiation. Ainsi, les conséquences d'une irradiation corps entier chez le porc se traduisent par une diminution importante et rapide de la sécrétion pancréatique exocrine, affectant à la fois les composantes hydro-bicarbonatée et enzymatique. Ce phénomène pourrait contribuer aux perturbations de la sphère intestinale lors du syndrome aigu d'irradiation mais également générer des effets à plus long terme.

The interface behaviour during PE-MOCVD deposition of Y2O3 thin films on Si/SiO2 (8 Å) substrates has been investigated by XPS, TEM and OES analysis. The deposition process involves the sequential injection of MO precursors into the CVD chamber and is assisted by an O2 plasma. The injection frequency greatly influences the interface behaviour in terms of thickness and composition. The O2 plasma and the solvent also greatly affect substrate oxidation, and subsequently interface formation during deposition. Several mechanisms are discussed to account for substrate oxidation in view of a careful control of interface formation.

Polypropylene metallized capacitors are of general use in power electronics because of their reliability, their self-healing capabilities, and their low price. Though the behavior of metallized coiled capacitors has been discussed, no work has been carried out on stacked and flattened metallized capacitors. The purpose of this article is to suggest an analytical model of resonance frequency, stray inductance and impedance of stacked capacitors. We first solve the equation of propagation of the magnetic potential vector (A) in the dielectric of an homogeneous material. Then, we suggest an original method of resolution, like the one used for resonant cavities, in order to present an analytical solution of the problem. Finally, we give some experimental results proving that the physical knowledge of the parameters of the capacitor (dimension of the component, and material constants), enables us to calculate an analytical model of resonance frequency, stray inductance and impedance of stacked capacitors.

Nanocrystalline titanium dioxide was prepared via aerosol pyrolysis of titanium alkoxide precursor at 200–580 °C in air and in nitrogen atmospheres. Powders were characterized by x-ray diffraction, thermogravimetric analysis, Brunauer–Emmett–Teller analysis, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, x-ray fluorescence, Raman and infrared spectroscopy, and Berner-type low-pressure impactor. The anatase phase transition was initiated at 500 °C in nitrogen and at 580 °C in air. Under other conditions amorphous powders were observed and transformed to nanocrystalline TiO2 via thermal postannealing. In air, smooth and spherical particles with 2–4-μm diameter were formed with an as-expected tendency to convert to rutile in the thermal postannealings. In nitrogen, a fraction of the titanium tetrabutoxide precursor evaporated and formed ultrafine particles via the gas-to-particle conversion. At 500 °C thermally stable anatase phase was formed in nitrogen. A specific surface area as high as 280 m2 g−1 was observed for an as-prepared powder.