Comparative performance of squeeze film air journal bearings made of aluminium and copper

This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. Copyright @ 2012 The Authors - The article can be accessed from the links below.This article has been made available through the Brunel Open Access Publishing Fund.Two tubular squeeze film journal bearings, made from Al 2024 T3 and Cu C101, were excited by driving the single-layer piezoelectric actuators at a 75-V AC with a 75-V DC offset. The input excitation frequencies were coincident with the 13th modal frequency, at 16.32 and 12.18 kHz for the respective Al and Cu bearings, in order to produce a ‘triangular’ modal shape. The paper also provided a CFX model, used to solve the Reynolds equation and the equation of motion, to explain the squeeze film effect of an oscillating plate with pressure end leakage. The dynamic characteristics of both bearings were studied in ANSYS and then validated by experiments with respect to their squeeze film thickness and load-carrying capacity. It was observed that whilst both bearings did levitate a load when excited at mode 13, the Al bearing showed a better floating performance than Cu bearing. This is due to the fact that the Al bearing had a higher modal frequency and a greater amplitude response than the Cu bearing.This article is made available through the Brunel Open Access Publishing Fund

Hecke-Clifford Algebras and Spin Hecke Algebras IV: Odd Double Affine Type

We introduce an odd double affine Hecke algebra (DaHa) generated by a classical Weyl group W and two skew-polynomial subalgebras of anticommuting generators. This algebra is shown to be Morita equivalent to another new DaHa which are generated by W and two polynomial-Clifford subalgebras. There is yet a third algebra containing a spin Weyl group algebra which is Morita (super)equivalent to the above two algebras. We establish the PBW properties and construct Verma-type representations via Dunkl operators for these algebras

QCD corrections to e^+ e^- to J/\psi(\psi(2S))+\chi_{cJ} (J=0,1,2) at B Factories

We analytically calculate the cross sections of double charmonium production in $e^+ e^- \to J/\psi(\psi(2S))\chi_{cJ}$ (J=0,1,2) at next-to-leading order (NLO) in $\alpha_s$ in nonrelativistic QCD, and confirm factorization of these processes. In contrast to $\chi_{c0}$ production, for which the NLO correction is large and positive, the NLO corrections for $\chi_{c1,2}$ production can be negative, resulting in decreased $K$ factors of 0.91 and 0.78 for J=1 and 2 respectively when $\mu = 2 m_{c}$. Consequently, the NLO QCD corrections markedly enlarge the difference between cross sections of $\chi_{c0}$ and $\chi_{c1,2}$. This may explain why $e^+ e^- \to J/\psi(\psi(2S))\chi_{c0}$ but not $e^+ e^- \to J/\psi(\psi(2S))\chi_{c1,2}$ is observed experimentally. Moreover, for $J/\psi(\psi(2S))\chi_{c1,2}$, the NLO QCD corrections substantially reduce the $\mu$ dependence and lead to predictions with small theoretical uncertainties.Comment: Version published in PRD, 6 pages, 3 figures, 2 tables, one reference adde

J/psi (psi') production at the Tevatron and LHC at O(\alpha_s^4v^4) in nonrelativistic QCD

We present a complete evaluation for \jpsi(\psip) prompt production at the Tevatron and LHC at next-to-leading order in nonrelativistic QCD, including color-singlet, color-octet, and higher charmonia feeddown contributions. The short-distance coefficients of \pj at next-to-leading order are found to be larger than leading order by more than an order of magnitude but with a minus sign at high transverse momentum $p_T$. Two new linear combinations of color-octet matrix elements are obtained from the CDF data, and used to predict \jpsi production at the LHC, which agrees with the CMS data. The possibility of \sa dominance and the \jpsi polarization puzzle are also discussed.Comment: Version published in PRL, 4 pages, 4 figure

Algebraic Degeneracy of Non-Archimedean Analytic Maps

We prove non-Archimedean analogs of results of Noguchi and Winkelmann showing algebraic degeneracy of rigid analytic maps to projective varieties omitting an effective divisor with sufficiently many irreducible components relative to the rank of the group they generate in the Neron-Severi group of the variety.Comment: 10 page

Epigenomes in Cardiovascular Disease.

If unifying principles could be revealed for how the same genome encodes different eukaryotic cells and for how genetic variability and environmental input are integrated to impact cardiovascular health, grand challenges in basic cell biology and translational medicine may succumb to experimental dissection. A rich body of work in model systems has implicated chromatin-modifying enzymes, DNA methylation, noncoding RNAs, and other transcriptome-shaping factors in adult health and in the development, progression, and mitigation of cardiovascular disease. Meanwhile, deployment of epigenomic tools, powered by next-generation sequencing technologies in cardiovascular models and human populations, has enabled description of epigenomic landscapes underpinning cellular function in the cardiovascular system. This essay aims to unpack the conceptual framework in which epigenomes are studied and to stimulate discussion on how principles of chromatin function may inform investigations of cardiovascular disease and the development of new therapies

QCD radiative correction to color-octet J/ψJ/\psi inclusive production at B Factories

In nonrelativistic Quantum Chromodynamics (NRQCD), we study the next-to-leading order (NLO) QCD radiative correction to the color-octet $J/\psi$ inclusive production at B Factories. Compared with the leading-order (LO) result, the NLO QCD corrections are found to enhance the short-distance coefficients in the color-octet $J/\psi$ production $e^+ e^-\to c \bar c (^3P_0^{(8)} {\rm or} ^3P_0^{(8)})g$ by a factor of about 1.9. Moreover, the peak at the endpoint in the $J/\psi$ energy distribution predicted at LO can be smeared by the NLO corrections, but the major color-octet contribution still comes from the large energy region of $J/\psi$. By fitting the latest data of $\sigma(e^{+}e^{-}\to J/\psi+X_{\mathrm{non-c\bar{c}}})$ observed by Belle, we find that the values of color-octet matrix elements are much smaller than expected earlier by using the naive velocity scaling rules or extracted from fitting experimental data with LO calculations. As the most stringent constraint by setting the color-singlet contribution to be zero in $e^{+}e^{-}\to J/\psi+X_{\mathrm{non-c\bar{c}}}$, we get an upper limit of the color-octet matrix element, $+ 4.0 <0| {\cal O}^{J/\psi} [{}^3P_0^{(8)}]|0>/m_c^2 <(2.0 \pm 0.6)\times 10^{-2} {\rm GeV}^3$ at NLO in $\alpha_s$.Comment: 18 pages, 8 figure

An Optimization Model of Banking Outlets Integration Based on the Network Comprehensive Analysis

The distribution of real banking outlets is based on the establishment of branches according to administrative division, which is obviously not rational in distribution. Against this phenomenon, this paper first analyzes the major factors that affect the distribution of outlets. Then, based on complex network, it puts forward the distribution model of outlets. Finally, it analyzes the model. At the same time, the paper takes the banking outlets of China Construction Bank of Wuxi City, Jiangsu Province for example. It employs the model to distribute and integrate its banking outlets. As a result, the distribution after integrating is more rational than the previous distribution, which verifies the rationality of the model and the distribution method of banking outlets