An Elliptical Galaxy Luminosity Function and Velocity Dispersion Sample of Relevance for Gravitational Lensing Statistics

We have selected 42 elliptical galaxies from the literature and estimated their velocity dispersions at the effective radius (\sigma_{\re}) and at 0.54 effective radii (\vff). We find by a dynamical analysis that the normalized velocity dispersion of the dark halo of an elliptical galaxy \vdm is roughly \sigma_{\re} multiplied by a constant, which is almost independent of the core radius or the anisotropy parameter of each galaxy. Our sample analysis suggests that \vdm^{*} lies in the range 178-198 km s$^{-1}$. The power law relation we find between the luminosity and the dark matter velocity dispersion measured in this way is (L/L^{*}) = (\vdm/\vdm^{*})^\gamma, where $\gamma$ is between 2-3. These results are of interest for strong gravitational lensing statistics studies. In order to determine the value of \vdm^{*}, we calculate \mstar in the same \bt band in which \vdm^{*} has been estimated. We select 131 elliptical galaxies as a complete sample set with apparent magnitudes \bt between 9.26 and 12.19. We find that the luminosity function is well fitted to the Schechter form, with parameters \mstar = -19.66 + 5$\cdot\log_{10}h \pm 0.30$, $\alpha = 0.15 \pm 0.55$, and the normalization constant $\phi^{*} = (1.34 \pm 0.30) \times 10^{-3} h^{3}$ Mpc$^{-3}$, with the Hubble constant \hnot = 100 $h$ km s$^{-1}$ Mpc$^{-1}$. This normalization implies that morphology type E galaxies make up (10.8 $\pm$ 1.2) per cent of all galaxies.Comment: 18 pages latex, with ps figs included. accepted by New Astronomy (revised to incorporate referees comments

An Algorithmic Framework for Efficient Large-Scale Circuit Simulation Using Exponential Integrators

We propose an efficient algorithmic framework for time domain circuit simulation using exponential integrator. This work addresses several critical issues exposed by previous matrix exponential based circuit simulation research, and makes it capable of simulating stiff nonlinear circuit system at a large scale. In this framework, the system's nonlinearity is treated with exponential Rosenbrock-Euler formulation. The matrix exponential and vector product is computed using invert Krylov subspace method. Our proposed method has several distinguished advantages over conventional formulations (e.g., the well-known backward Euler with Newton-Raphson method). The matrix factorization is performed only for the conductance/resistance matrix G, without being performed for the combinations of the capacitance/inductance matrix C and matrix G, which are used in traditional implicit formulations. Furthermore, due to the explicit nature of our formulation, we do not need to repeat LU decompositions when adjusting the length of time steps for error controls. Our algorithm is better suited to solving tightly coupled post-layout circuits in the pursuit for full-chip simulation. Our experimental results validate the advantages of our framework.Comment: 6 pages; ACM/IEEE DAC 201

CO2 Capture by Aqueous Solution Containing Mixed Alkanolamines and Diethylene Glycol in a Rotating Packed Bed

AbstractIn this study, an effective absorbent, 23.5% diethylenetriamine (DETA)/19.6% piperazine (PZ)/37.7% diethylene glycol (DEG)/19.2% H2 O, was proposed to capture CO2 from a nitrogen gas stream containing 10% of CO2 in a rotating packed bed (RPB). The addition of DEG could improve the solubility of PZ in absorbent, and there was no precipitation observed in CO2 - rich solution after CO2 absorption for the proposed absorbent. The regeneration energy could be reduced because the heat capacity and vapor pressure of DEG are lower than that of water. The higher gas-liquid contact area and mass transfer rate as well as the smaller size were observed in a RPB as compared with a packed bed to achieve the same CO2 capture efficiency

Information System Development Team Collaboration Antecedents

Despite information system development companies have invested substantial resources to support the success of information system development (ISD) projects, the failure rate is still high. Extant studies indicated that the constant changes from socio-technical environments are the main causes of the low success rate. This study argues that team collaboration is a key factor to effectively cope with unexpected disruptions that would have negative effect on overall software product success. This study proposes a research model exploring factors that influence the development of team collaboration. These factors include the team commitment, transactive memory systems (TMS), and collective mind. In addition, the study suggests that the collective mind has an intermediate effect on the team commitment, TMS, and team collaboration. This study takes the information development teams of various companies in Taiwan as its subjects

Motion Compensation Along All Three Different Directions

This unit addresses how one can deal with phase perturbations that arise due to the presence of motion. Techniques to reduce or remove their associated artifacts are explained in detail. Artifacts due to phase changes that come from the read gradient, from the slice select gradient and from the phase encoding gradient are also discussed.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145397/1/cpmib0702.pd

Use of FBG optical sensors for structural health monitoring: Practical application

This paper describes the development of FBG Optical sensors for their practical application on structural health monitoring. The sensors were installed on the Tsing Ma Bridge for a trial run. The results using FBG sensors were in excellent agreement with those acquired by the bridge WASHMS