Two-scale EHL: three-dimensional topography in tilted-pad bearings

Derived from the Heterogeneous Multiscale Methods (HMM), a two-scale method is developed for the analysis of Elastohydrodynamic Lubrication (EHL) and micro-EHL in tilted-pad bearings with three-dimensional topography. A relationship linking the pressure gradient to mass flow rate is derived and represented in the bearing domain through homogenisation of near-periodic simulations describing the Fluid Structure Interaction (FSI) of topographical features. For the parameters investigated the influence of compressibility and piezoviscosity was found to be more significant than that of non-Newtonian (shear-thinning) behaviour on textured bearing performance. As the size of topography increased two-scale solutions demonstrated that at constant load the coefficient of friction increased and the minimum film thickness decreased over a range of pad lengths and tilt angles

The SUrvey for Pulsars and Extragalactic Radio Bursts – II. New FRB discoveries and their follow-up

We report the discovery of four Fast Radio Bursts (FRBs) in the ongoing SUrvey for Pulsars and Extragalactic Radio Bursts at the Parkes Radio Telescope: FRBs 150610, 151206, 151230 and 160102. Our real-time discoveries have enabled us to conduct extensive, rapid multimessenger follow-up at 12 major facilities sensitive to radio, optical, X-ray, gamma-ray photons and neutrinos on time-scales ranging from an hour to a few months post-burst. No counterparts to the FRBs were found and we provide upper limits on afterglow luminosities. None of the FRBs were seen to repeat. Formal fits to all FRBs show hints of scattering while their intrinsic widths are unresolved in time. FRB 151206 is at low Galactic latitude, FRB 151230 shows a sharp spectral cut-off, and FRB 160102 has the highest dispersion measure (DM = 2596.1 ± 0.3 pc cm−3) detected to date. Three of the FRBs have high dispersion measures (DM > 1500 pc cm−3), favouring a scenario where the DM is dominated by contributions from the intergalactic medium. The slope of the Parkes FRB source counts distribution with fluences >2 Jy ms is α=−2.2+0.6−1.2 and still consistent with a Euclidean distribution (α = −3/2). We also find that the all-sky rate is 1.7+1.5−0.9×103 FRBs/(4π sr)/day above ∼2Jyms and there is currently no strong evidence for a latitude-dependent FRB sky rate

An elementary proof of the hitting time theorem

No abstract

Acidities and catalytic activities of persulfonated poly(styrene-co-divinylbenzene) ion-exchange resins

A series of macroporous sulfonated poly(styrene-co-divinylbenzene) ion-exchange resins with varying levels of sulfonation have been prepared. The acidities of these resins have been measured calorimetrically by ammonia sorption. Catalytic activities have been measured in two liquid-phase reactions: the dehydration of 1-hexanol under flow conditions and the hydration of propene as a batch process. The molar enthalpies of ammonia sorption show that the strength of the acid sites increases as the level of sulfonation is increased; catalytic activities follow the same trend. The most active resins are those that have been sulfonated at levels above one sulfonic acid group per aromatic ring (persulfonated). These persulfonated resins also show higher thermal stabilities than conventional resins (sulfonated at just below one acid group per aromatic ring)

<特集I>西塚泰美元学長を偲んで

Changes in intracoronary volume reflect the hemodynamic significance of progression or regression of diffuse coronary artery disease where intracoronary catheters cannot be applied for direct measurements due to small vessel dimensions. We have validated the videodensitometric measurement of intracoronary volume with epoxy casts of postmortem human coronary arteries. The volume of 31 coronary segments (cross-sectional areas in a range of 2-13 mm2) measured by fluid-filling using a precision dispenser was compared with the respective single plane intracoronary volume assessments obtained by the videodensitometric algorithm of the new generation Cardiovascular Angiography Analysis System (CAAS II). The true and measured values of volume were compared by calculation of the mean of the signed differences +/- standard deviation and by linear regression analysis. Videodensitometric measurement of intracoronary volume correlate well with fluid-filling of human coronary artery casts (correlation coefficient: r = 0.99, y = 1.96 +/- 0.99x, standard error of estimate: SEE = 3.96) with a significant trend towards overestimation of true volume values (mean difference = 1.73 +/- 3.64 mm3, P < 0.05). Intracoronary volume estimations can be used to measure changes of luminal dimensions of coronary arteries and may offer a new approach to assessment of progression or regression of diffuse coronary artery disease