Enhancement of speed and efficiency of an Internet based gear design optimisation

An internet-based gear design optimisation program has been developed for geographically dispersed teams to collaborate over the internet. The optimisation program implements genetic algorithm. A novel methodology is presented that improves the speed of execution of the optimisation program by integrating artificial neural networks into the system. The paper also proposes a method that allows an improvement to the performance of the back propagation-learning algorithm. This is done by rescaling the output data patterns to lie slightly below and above the two extreme values of the full range neural activation function. Experimental tests show the reduction of execution time by approximately 50%, as well as an improvement in the training and generalisation errors and the rate of learning of the network

Enhanced acoustic transmission through a slanted grating

It is known that an acoustic wave incident on an infinite array of aligned rectangular blocks of a different acoustic material exhibits total transmission if certain conditions are met [1] which relate the unique "intromission" angle of incidence with geometric and material properties of the slab. This extraordinary acoustic transmission phenomenon holds for any slab thickness, making it analogous to a Brewster effect in optics, and is independent of frequency as long as the slab microstructure is sub-wavelength in the length-wise direction. Here we show that the enhanced transmission effect is obtained in a slab with grating elements oriented obliquely to the slab normal. The dependence of the intromission angle $\theta_i$ is given explicitly in terms of the orientation angle. Total transmission is achieved at incidence angles $\pm \theta_i$, with a relative phase shift between the transmitted amplitudes of the $+\theta_i$ and $- \theta_i$ cases. These effects are shown to follow from explicit formulas for the transmission coefficient. In the case of grating elements that are rigid the results have direct physical interpretation. The analytical findings are illustrated with full wave simulations.Comment: 15 page, 16 figure

Closed expression of the interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states

The interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states is derived from the Bethe-Salpeter equations satisfied by the quark-antiquark four-point Green's function. The latter equations are established based on the equations of motion obeyed by the quark and antiquark propagators, the four-point Green's function and some other kinds of Green's functions which follow directly from the QCD generating functional. The B-S kernel derived is given an exact and explicit expression which contains only a few types of Green's functions. This expression is not only convenient for perturbative calculations, but also suitable for nonperturbative investigations.Comment: 27 pages,no figure

Similarity between the primary and secondary air-assisted liquid jet breakup mechanism

we report an ultrafast synchrotron x-ray phase contrast imaging study of the primary breakup mechanism of a coaxial air-assisted water jet. We demonstrate that there exist great similarities in the phenomenology of primary breakup with that of the secondary breakup. Especially, a membrane-mediated breakup mechanism dominates the breakup process for a wide range of air speeds. This finding reveals the intrinsic connections of these two breakup regimes and has deep implications on the unified theoretical approach in treating the breakup mechanism of high speed liquid jet.Comment: 15 pages, 4 figure

Multi-user Internet environment for gear design optimization

A Web based multi-user system has been developed to remotely execute a large size software package via the Internet. The software implements genetic algorithm to optimize the design of spur and helical gears. To accomplish this, a combination of HTML, JavaServlets, JavaApplets, JavaScript and HTTP protocol has been employed

Pre-flare coronal dimmings

In this paper, we focus on the pre-flare coronal dimmings. We report our multiwavelength observations of the GOES X1.6 solar flare and the accompanying halo CME produced by the eruption of a sigmoidal magnetic flux rope (MFR) in NOAA active region (AR) 12158 on 2014 September 10. The eruption was observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamic Observatory (SDO). The photospheric line-of-sight magnetograms were observed by the Helioseismic and Magnetic Imager (HMI) aboard SDO. The soft X-ray (SXR) fluxes were recorded by the GOES spacecraft. The halo CME was observed by the white light coronagraphs of the Large Angle Spectroscopic Coronagraph (LASCO) aboard SOHO.} {About 96 minutes before the onset of flare/CME, narrow pre-flare coronal dimmings appeared at the two ends of the twisted MFR. They extended very slowly with their intensities decreasing with time, while their apparent widths (8$-$9 Mm) nearly kept constant. During the impulsive and decay phases of flare, typical fanlike twin dimmings appeared and expanded with much larger extent and lower intensities than the pre-flare dimmings. The percentage of 171 {\AA} intensity decrease reaches 40\%. The pre-flare dimmings are most striking in 171, 193, and 211 {\AA} with formation temperatures of 0.6$-$2.5 MK. The northern part of the pre-flare dimmings could also be recognized in 131 and 335 {\AA}.} To our knowledge, this is the first detailed study of pre-flare coronal dimmings, which can be explained by the density depletion as a result of the gradual expansion of the coronal loop system surrounding the MFR during the slow rise of the MFR.Comment: 6 pages, 8 figures, to be accepted for publication by A&

Comparison of Compliance with Cervical Cancer Screening among Women aged 18 and above in Arkansas and the United States

Introduction: Cervical cancer preys on women without access to preventative screening. Any woman who has developed an invasive case of cervical cancer should be regarded as a failure of screening. Disparities in access to screening, triage, and treatment fuel an uneven distribution in the burden of cervical cancer within the United States; weighing unusually heavy on the Southern States like Arkansas. The purpose of this study was to evaluate demographic and behavioral risk factors for cervical cancer and identify potential barriers which may influence the likelihood of complying with current Pap test recommendations on a state level, in Arkansas, and also a national scale, in the United States. Materials and Methods: National data from the 2014 Behavioral Risk Factor Survey System (BRFSS) was used to collect demographic characteristics and behavioral risk factors among females aged 18 and above in Arkansas and the United States. BFRSS data included a total of 1,587 women in Arkansas and 162,222 in the United States who were aged 18 and above and eligible to receive Pap tests. Women with a medical history of hysterectomy that included the removal of the cervix were excluded from analysis because they are not considered to be medically eligible to receive Pap tests. Results: Socioeconomic status, age, race, and health insurance were significantly associated with likelihood to comply with current screening recommendations among women in both Arkansas and the United States. Arkansan women who had less than a 12-year education (Odds Ratio (OR) = 1.41, 95% Confidence Interval (CI) = 1.04, 1.64) and were without health insurance (OR = 3.56, 95% CI = 1.66, 7.66) were more likely to be non-compliant with Pap testing, which is similar to the finding on the national level. The prevalence of Pap test compliance was significantly lower among women in Arkansas when compared to US average in every sociodemographic sector. Discussion: According to US Census data collected in 2013, Arkansas had the highest cervical cancer incidence of 10.6 per 100,000 person-years, while the national average was 7.7 per 100,000 person-years. Therefore, future population-based cervical cancer interventions in Arkansas should target the promotion of Pap test compliance among the most vulnerable subpopulations (i.e., low socioeconomic status, minority, medically under or uninsured). Organized screening interventions might include offering free or reduced cost Pap testing in both urban and rural locations