Steady state and dynamic properties of journal bearings in laminar and superlaminar flow regimes. II - Full floating ring bearings

Steady state and dynamic properties of journal bearings in laminar and superlaminar flow regime

Time-Varying Volatility and the Dynamic Behavior of the Term Structure

In this paper, we consider a framework with which the cross sectional and time series behavior of the yield curve can be studied simultaneously. We examine the relationship between the yield curve and the time-varying conditional volatility of the Treasury bill market. We demonstrate that differently shaped yield curves can result given different combinations of volatility and expectations about future spot rates. Moreover, adjusting the forward rate for the volatility related liquidity premium can improve its performance as a predictor of future spot rates at least for the period from August 1964 to August 1979.

Measuring and Testing the Impact of News on Volatility

This paper introduces the News Impact Curve to measure how new information is incorporated into volatility estimates. A variety of new and existing ARCH models are compared and estimated with daily Japanese stock return data to determine the shape of the News Impact Curve. New diagnostic tests are presented which emphasize the asymmetry of the volatility response to news. A partially non-parametric ARCH model is introduced to allow the data to estimate this shape. A comparison of this model with the existing models suggests that the best models are one by Glosten Jaganathan and Runkle (GJR) and Nelson's EGARCE. Similar results hold on a pre-crash sample period but are less strong.

Field #3 of the Palomar-Groningen Survey II. Near-infrared photometry of semiregular variables

Near-infrared photometry (JHKL'M) was obtained for 78 semiregular variables (SRVs) in field #3 of the Palomar-Groningen survey (PG3, l=0, b=-10). Together with a sample of Miras in this field a comparison is made with a sample of field SRVs and Miras. The PG3 SRVs form a sequence (period-luminosity & period-colour) with the PG3 Miras, in which the SRVs are the short period extension to the Miras. The field and PG3 Miras follow the same P/(J--K)o relation, while this is not the case for the field and PG3 SRVs. Both the PG3 SRVs and Miras follow the SgrI period-luminosity relation adopted from Glass et al. (1995, MNRAS 273, 383). They are likely pulsating in the fundamental mode and have metallicities spanning the range from intermediate to approximately solar.Comment: 14 pages LaTeX (2 tables, 8 figures), to appear in A&A 338 (1998); minor modifications in tex

Supersolid phase in spin dimer XXZ systems under magnetic field

Using quantum Monte Carlo method, we study, under external magnetic fields, the ground state phase diagram of the two-dimensional spin $S$=1/2 dimer model with an anisotropic intra-plane antiferromagnetic coupling. With the anisotropy $4 \gtrsim \Delta \gtrsim 3$, a supersolid phase characterized by a non-uniform bose condensate density that breaks translational symmetry is found. The rich phase diagram also contains a checkerboard solid and two different types of superfluid phase formed by $S_z=+1$ and $S_z=0$ spin triplets, with finite staggered magnetization in z-axis and in-plane direction, respectively. As we show, the model can be realized as a consequence of including the next nearest neighbor coupling among dimers and our results suggest that spin dimer systems may be an ideal model system to study the supersolid phase.Comment: 4 pages, 5 figure

Precise LIGO Lensing Rate Predictions for Binary Black Holes

We show how LIGO is expected to detect coalescing binary black holes at $z>1$, that are lensed by the intervening galaxy population. Gravitational magnification, $\mu$, strengthens gravitational wave signals by $\sqrt{\mu}$, without altering their frequencies, which if unrecognised leads to an underestimate of the event redshift and hence an overestimate of the binary mass. High magnifications can be reached for coalescing binaries because the region of intense gravitational wave emission during coalescence is so small ($\sim$100km), permitting very close projections between lensing caustics and gravitational-wave events. Our simulations incorporate accurate waveforms convolved with the LIGO power spectral density. Importantly, we include the detection dependence on sky position and orbital orientation, which for the LIGO configuration translates into a wide spread in observed redshifts and chirp masses. Currently we estimate a detectable rate of lensed events \rateEarly{}, that rises to \rateDesign{}, at LIGO's design sensitivity limit, depending on the high redshift rate of black hole coalescence.Comment: 5 pages, 4 figure

Spin-Orbit Coupling and Symmetry of the Order Parameter in Strontium Ruthenate

Determination of the orbital symmetry of a state in spin triplet Sr$_2$RuO$_4$ superconductor is a challenge of considerable importance. Most of the experiments show that the chiral state of the $\hat{z} (k_x \pm ik_y)$ type is realized and remains stable on lowering the temperature. Here we have studied the stability of various superconducting states of Sr$_2$RuO$_4$ in the presence of spin-orbit coupling. Numerically we found that the chiral state is never the minimum energy. Alone among the five states studied it has $=0$ and is therefore not affected to linear order in the coupling parameter $\lambda$. We found that stability of the chiral state requires spin dependent pairing interactions. This imposes strong constraint on the pairing mechanism.Comment: 4 pages, 4 figure