Numerical Optimisation for the Evaluation of Combustion Kinetic Models

AbstractFour optimisation methods have been chosen and implemented for optimising kinetic parameters with respect to a set of experimental data. They were first successfully validated via specifically tailored minimisation problems where kinetic coefficients had been varied so as to produce discrepancies with the initial predictions of the GRI (Gas Research Institute) mechanism 3.0. Three of them could retrieve an almost perfect agreement whereas the fourth approach found a slightly sub-optimal solution. Afterwards, a set of CH3−O2 and C2H6−O2 oxidation experiments inconsistent with the initial values of GRI 3.0 were considered. It could be shown that the parameters of the most sensitive reactions could not be optimised under reasonable limits, thereby indicating that these experiments are probably not predictable by GRI 3.0

Six-dimensional weak-strong simulations of head-on beam-beam compensation in RHIC

To compensate the large beam-beam tune spread and beam-beam resonance driving terms in the polarized proton operation in the Relativistic Heavy Ion Collider (RHIC), we will introduce a low-energy DC electron beam into each ring to collide head-on with the opposing proton beam. The device to provide the electron beam is called an electron lens. In this article, using a 6-D weak-strong-beam-beam interaction simulation model, we investigate the effects of head-on beam-beam compensation with electron lenses on the proton beam dynamics in the RHIC 250 GeV polarized proton operation. This article is abridged from the published article [1].Comment: 5 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201

Computer-based estimation system for land productivity

International Science and Education Researcher Association (ISER); Gireida Education Co. Ltd; Wuhan University of Science and Technology; VIP Information Conference Center<span class="MedBlackText">Land productivity generally refers to the overall productivity related to various combinations of the natural characteristics of the land and socioeconomic factors. Structural change and pattern succession in land systems undoubtedly leads to changes in the suitability and quality of different kinds of land types and directly influences agricultural productivity. In this paper we describe the processes, parameters needed and methods of data preparation, which will improve the ability of readers to use this model and provide a foundation for its wide application.</span

An integrated 3.1-5.1 GHz pulse generator for ultra-wideband wireless localization systems

This paper presents an implementation of an integrated Ultra-wideband (UWB), Binary-Phase Shift Keying (BPSK) Gaussian modulated pulse generator. VCO, multiplier and passive Gaussian filter are the key components. The VCO provides the carrier frequency of 4.1 GHz, the LC Gaussian filter is responsible for the pulse shaping in the baseband. Multiplying the baseband pulse and the VCO frequency shifts the pulse to the desired center frequency. The generated Gaussian pulse ocupppies the frequency range from 3.1 to 5.1 GHz with the center frequency at 4.1 GHz. Simulations and measured results show that this spectrum fulfills the mask for indoor communication systems given by the FCC (Federal Communications Commission, 2002). The total power consumption is 55 mW using a supply voltage of 2.5 V. Circuits are realized using the IHP 0.25 μm SiGe:C BiCMOS technology

A combined spectroscopic and photometric stellar activity study of Epsilon Eridani

We present simultaneous ground-based radial velocity (RV) measurements and space-based photometric measurements of the young and active K dwarf Epsilon Eridani. These measurements provide a data set for exploring methods of identifying and ultimately distinguishing stellar photospheric velocities from Keplerian motion. We compare three methods we have used in exploring this data set: Dalmatian, an MCMC spot modeling code that fits photometric and RV measurements simultaneously; the FF$'$ method, which uses photometric measurements to predict the stellar activity signal in simultaneous RV measurements; and H$\alpha$ analysis. We show that our H$\alpha$ measurements are strongly correlated with photometry from the Microvariability and Oscillations of STars (MOST) instrument, which led to a promising new method based solely on the spectroscopic observations. This new method, which we refer to as the HH$'$ method, uses H$\alpha$ measurements as input into the FF$'$ model. While the Dalmatian spot modeling analysis and the FF$'$ method with MOST space-based photometry are currently more robust, the HH$'$ method only makes use of one of the thousands of stellar lines in the visible spectrum. By leveraging additional spectral activity indicators, we believe the HH$'$ method may prove quite useful in disentangling stellar signals

Early-type Stars: Most Favorable Targets for Astrometrically Detectable Planets in the Habitable Zone

Early-type stars appear to be a difficult place to look for planets astrometrically. First, they are relatively heavy, and for fixed planetary mass the astrometric signal falls inversely as the stellar mass. Second, they are relatively rare (and so tend to be more distant), and for fixed orbital separation the astrometric signal falls inversely as the distance. Nevertheless, because early-type stars are relatively more luminous, their habitable zones are at larger semi-major axis. Since astrometric signal scales directly as orbital size, this gives early-type stars a strong advantage, which more than compensates for the other two factors. Using the Hipparcos catalog, we show that early-type stars constitute the majority of viable targets for astrometric searches for planets in the habitable zone. We contrast this characteristic to transit searches, which are primarily sensitive to habitable planets around late-type stars.Comment: Submitted to ApJ Letters, 8 pages including 2 figure

A Planetary Companion to the Nearby M4 Dwarf, Gliese 876

Doppler measurements of the M4 dwarf star, Gliese 876, taken at both Lick and Keck Observatory reveal periodic, Keplerian velocity variations with a period of 61 days. The orbital fit implies that the companion has a mass of, M = 2.1 MJUP /sin i, an orbital eccentricity of, e = 0.27+-0.03, and a semimajor axis of, a = 0.21 AU. The planet is the first found around an M dwarf, and was drawn from a survey of 24 such stars at Lick Observatory. It is the closest extrasolar planet yet found, providing opportunities for follow--up detection. The presence of a giant planet on a non-circular orbit, 0.2 AU from a 1/3 M_Sun star, presents a challenge to planet formation theory. This planet detection around an M dwarf suggests that giant planets are numerous in the Galaxy.Comment: 13 pages, 3 Figure

A New Planet Around an M Dwarf: Revealing a Correlation Between Exoplanets and Stellar Mass

We report precise Doppler measurements of GJ317 (M3.5V) that reveal the presence of a planet with a minimum mass Msini = 1.2 Mjup in an eccentric, 692.9 day orbit. GJ317 is only the third M dwarf with a Doppler-detected Jovian planet. The residuals to a single-Keplerian fit show evidence of a possible second orbital companion. The inclusion of an additional Jupiter-mass planet (P = 2700 days, Msini = 0.83 Mjup) improves the quality of fit significantly, reducing the rms from 12.5 m/s to 6.32 m/s. A false-alarm test yields a 1.1% probability that the curvature in the residuals of the single-planet fit is due to random fluctuations, lending additional credibility to the two-planet model. However, our data only marginally constrain a two-planet fit and further monitoring is necessary to fully characterize the properties of the second planet. To study the effect of stellar mass on Jovian planet occurrence we combine our samples of M stars, Solar-mass dwarfs and intermediate-mass subgiants. We find a positive correlation between stellar mass and the occurrence rate of Jovian planets within 2.5 AU; the former A-type stars in our sample are nearly 5 times more likely than the M dwarfs to harbor a giant planet. Our analysis shows that the correlation between Jovian planet occurrence and stellar mass remains even after accounting for the effects of stellar metallicity.Comment: ApJ accepted, 27 pages, 6 figures, 3 table

Support vector machine applications in terahertz pulsed signals feature sets

Copyright © 2007 IEEE. All Rights Reserved.In the past decade, terahertz radiation (T-rays) have been extensively applied within the fields of industrial and biomedical imaging, owing to their noninvasive property. Support vector machine (SVM) learning algorithms are sufficiently powerful to detect patterns hidden inside noisy biomedical measurements. This paper introduces a frequency orientation component method to extract T-ray feature sets for the application of two- and multiclass classification using SVMs. Effective discriminations of ribonucleic acid (RNA) samples and various powdered substances are demonstrated. The development of this method has become important in T-ray chemical sensing and image processing, which results in enhanced detectability useful for many applications, such as quality control, security detection and clinic diagnosis.Xiaoxia Yin, Brian W.-H. Ng, Bernd M. Fischer, Bradley Ferguson, and Derek Abbot