Behavior of rod-like polyelectrolytes near an oppositely charged surface

The behavior of highly charged short rod-like polyelectrolytes near oppositely charged planar surfaces is investigated by means of Monte Carlo simulations. A detailed microstructural study, including monomer and fluid charge distribution, and chain orientation, is provided. The influence of chain length, substrate's surface-charge-density and image forces is considered. Due to the lower chain-entropy (compared to flexible chains), our simulation data show that rod-like polyelectrolytes can, in general, better adsorb than flexible ones do. Nonetheless, at low substrate-dielectric-constant, it is found that repulsive image forces tend to significantly reduce this discrepancy.Comment: Updated results - 19 pages - 10 figs - RevTex

Design of waveguides, bends and splitters in photonic crystal slabs with hexagonal holes in a triangular lattice

Waveguides in photonic crystal slabs (PCS) can be obtained by omitting a row of holes (W1-waveguides). In general the propagation properties in such waveguides suffer from the unavoidable periodic sidewall corrugation caused by the remaining parts of the crystal. The corrugation acts as a Bragg reflector, causing the occurrence of so-called mini stopbands in the transmission of the waveguide. The effect is quite strong in PCS with circular holes, but it can be significantly reduced if correctly oriented hexagonal holes are used. This so-called hexagon-type PCS allows the design of waveguides, bends and splitters having a relatively high group velocity and a wide transmission window in the PCS stopband for modes having their magnetic field oriented mainly perpendicular to the slab

Interleavers

The chapter describes principles, analysis, design, properties, and implementations of optical frequency (or wavelength) interleavers. The emphasis is on finite impulse response devices based on cascaded Mach-Zehnder-type filter elements with carefully designed coupling ratios, the so-called resonant couplers. Another important class that is discussed is the infinite impulse response type, based on e.g. Fabry-Perot, Gires-Tournois, or ring resonators

A hysteresis model for an orthogonal thin-film magnetometer

The operation of a ferromagnetic thin-film magnetometer using the anisotropic magnetoresistance effect in a permalloy film is discussed. Measurements showed the presence of a hysteresis effect not predicted by available models. It is shown that the sensitivity of the magnetometer is predicted by applying F.S. Greene and R.B. Yarbrough's (1970) orthogonal susceptibility model, and that the hysteresis can be explained by assuming dispersion in the magnitude of anisotropy. The orthogonal susceptibility model must be evaluated numerically, accounting for a finite driving field. The effect of an inhomogeneous demagnetizing field in the film is discussed in relation to magnitude dispersion of the anisotrop

Regularities and peculiarities of birth schedules in industrialized countries: an analysis of FFS data

Inter-individual diversity of women according to birth numbers (quantum) and birth spacing (tempo) are important for understanding of fertility regimes. Elsewhere, we have shown that diversity with respect to fertility quantum is increasing from older to younger cohorts. The present study looks at tempo dimension by decomposing the diversity of birth schedules. The data set contains pooled FFS data from 19 industrialized countries and covers 11124 women aged 40-44 at survey. The analyses include descriptive characteristics of birth schedules, their classification by cluster analysis, and the identification of some of the underlying factors by two types of regression analyses. The first of them is a multinomial logistic regression linking types of birth schedules with characteristics of women at the time of interview. The second includes event-history analyses examining the transition to second and third conception (leading to birth), where time since previous birth is combined with the current values of the covariates. Age at first birth is a major component of inter-individual differences in birth schedules and it largely determines their clustering. Distributions of second, third, and fourth births over time since the previous births are very similar to each other. The median length of birth intervals is 3-3.5 years and 75% of births occur within 5-6 years after the previous delivery. One cluster stands out of this regularity as it is characterized by long last birth interval of about 11 years. Age distributions of fertility for women from this cluster are bimodal and their shape points at unexpectedly “renewed” fertility careers. Additional births produced by the phenomenon compose about 6% of all births. Regression analyses show that the long last birth interval is associated with new partnerships. Some influence of contraceptive failure can not be excluded, too. More in-depth research is needed to learn about the dynamic factors of birth schedules and particularly about the relationship between entering new partnerships and childbearing.Europe, age distribution, birth spacing, fertility, fertility surveys

Managerial Ownership Dynamics and Firm Value

From 1988 to 2003, the average change in managerial ownership is significantly negative every year for American firms. The probability of large decreases in ownership is strongly increasing in contemporaneous and past stock returns but the probability of large increases in ownership through managerial purchases of shares is not. The relation between changes in Tobin's q and past and contemporaneous changes in ownership depends critically on controlling for past stock returns. When controlling for past stock returns, past large decreases in managerial ownership are unrelated to current changes in Tobin's q but there is some evidence that past large increases in managerial ownership are positively related to current changes in Tobin's q. Because managers sell shares when a firm's stock is performing well, large contemporaneous decreases in managerial ownership are associated with increases in Tobin's q. We argue that our evidence is mostly inconsistent with existing theories and propose a managerial discretion theory of ownership consistent with our evidence.

Global Sensitivity Methods for Design of Experiments in Lithium-ion Battery Context

Battery management systems may rely on mathematical models to provide higher performance than standard charging protocols. Electrochemical models allow us to capture the phenomena occurring inside a lithium-ion cell and therefore, could be the best model choice. However, to be of practical value, they require reliable model parameters. Uncertainty quantification and optimal experimental design concepts are essential tools for identifying systems and estimating parameters precisely. Approximation errors in uncertainty quantification result in sub-optimal experimental designs and consequently, less-informative data, and higher parameter unreliability. In this work, we propose a highly efficient design of experiment method based on global parameter sensitivities. This novel concept is applied to the single-particle model with electrolyte and thermal dynamics (SPMeT), a well-known electrochemical model for lithium-ion cells. The proposed method avoids the simplifying assumption of output-parameter linearization (i.e., local parameter sensitivities) used in conventional Fisher information matrix-based experimental design strategies. Thus, the optimized current input profile results in experimental data of higher information content and in turn, in more precise parameter estimates.Comment: Accepted for 21st IFAC World Congres