Apparatus for purging systems handling toxic, corrosive, noxious and other fluids Patent

Fluid transferring system design for purging toxic, corrosive, or noxious fluids and fumes from materials handling equipment for cleansing and accident preventio

Global minimum determination of the Born-Oppenheimer surface within density functional theory

We present a novel method, which we call dual minima hopping method (DMHM), that allows us to find the global minimum of the potential energy surface (PES) within density functional theory for systems where a fast but less accurate calculation of the PES is possible. This method can rapidly find the ground state configuration of clusters and other complex systems with present day computer power by performing a systematic search. We apply the new method to silicon clusters. Even though these systems have already been extensively studied by other methods, we find new configurations that are lower in energy than the previously found.Comment: 4 pages, 3 figures, minor changes, more structures are presented no

Influence of a magnetic field on the viscosity of a dilute gas consisting of linear molecules.

The viscomagnetic effect for two linear molecules, N2 and CO2, has been calculated in the dilute-gas limit directly from the most accurate ab initio intermolecular potential energy surfaces presently available. The calculations were performed by means of the classical trajectory method in the temperature range from 70 K to 3000 K for N2 and 100 K to 2000 K for CO2, and agreement with the available experimental data is exceptionally good. Above room temperature, where no experimental data are available, the calculations provide the first quantitative information on the magnitude and the behavior of the viscomagnetic effect for these gases. In the presence of a magnetic field, the viscosities of nitrogen and carbon dioxide decrease by at most 0.3% and 0.7%, respectively. The results demonstrate that the viscomagnetic effect is dominated by the contribution of the jj¯ polarization at all temperatures, which shows that the alignment of the rotational axes of the molecules in the presence of a magnetic field is primarily responsible for the viscomagnetic effect

Fitting theories of nuclear binding energies

In developing theories of nuclear binding energy such as density-functional theory, the effort required to make a fit can be daunting due to the large number of parameters that may be in the theory and the large number of nuclei in the mass table. For theories based on the Skyrme interaction, the effort can be reduced considerably by using the singular value decomposition to reduce the size of the parameter space. We find that the sensitive parameters define a space of dimension four or so, and within this space a linear refit is adequate for a number of Skyrme parameters sets from the literature. We do not find marked differences in the quality of the fit between the SLy4, the Bky4 and SkP parameter sets. The r.m.s. residual error in even-even nuclei is about 1.5 MeV, half the value of the liquid drop model. We also discuss an alternative norm for evaluating mass fits, the Chebyshev norm. It focuses attention on the cases with the largest discrepancies between theory and experiment. We show how it works with the liquid drop model and make some applications to models based on Skyrme energy functionals. The Chebyshev norm seems to be more sensitive to new experimental data than the root-mean-square norm. The method also has the advantage that candidate improvements to the theories can be assessed with computations on smaller sets of nuclei.Comment: 17 pages and 4 figures--version encorporates referee's comment

A Bell-Evans-Polanyi principle for molecular dynamics trajectories and its implications for global optimization

The Bell-Evans-Polanyi principle that is valid for a chemical reaction that proceeds along the reaction coordinate over the transition state is extended to molecular dynamics trajectories that in general do not cross the dividing surface between the initial and the final local minima at the exact transition state. Our molecular dynamics Bell-Evans-Polanyi principle states that low energy molecular dynamics trajectories are more likely to lead into the basin of attraction of a low energy local minimum than high energy trajectories. In the context of global optimization schemes based on molecular dynamics our molecular dynamics Bell-Evans-Polanyi principle implies that using low energy trajectories one needs to visit a smaller number of distinguishable local minima before finding the global minimum than when using high energy trajectories

Credit and Equity Rationing in Markets with Adverse Selection

Previous theories of financial market rationing focused on a single market, either the credit or the equity market. An interesting question is whether credit and equity rationing are mutually compatible, and how they interact. We consider a model with two-dimensional asymmetric information, where entrepreneurs have private information about both the expected returns and the risk of their projects. We show that credit and equity rationing may occur individually or simultaneously. Moreover, competition between the two markets may generate the adverse selection that leads to rationing outcomes

Relic density of wino-like dark matter in the MSSM

The relic density of TeV-scale wino-like neutralino dark matter in the MSSM is subject to potentially large corrections as a result of the Sommerfeld effect. A recently developed framework enables us to calculate the Sommerfeld-enhanced relic density in general MSSM scenarios, properly treating mixed states and multiple co-annihilating channels as well as including off-diagonal contributions. Using this framework, including on-shell one-loop mass splittings and running couplings and taking into account the latest experimental constraints, we perform a thorough study of the regions of parameter space surrounding the well known pure-wino scenario: namely the effect of sfermion masses being non-decoupled and of allowing non-negligible Higgsino or bino components in the lightest neutralino. We further perform an investigation into the effect of thermal corrections and show that these can safely be neglected. The results reveal a number of phenomenologically interesting but so far unexplored regions where the Sommerfeld effect is sizeable. We find, in particular, that the relic density can agree with experiment for dominantly wino neutralino dark matter with masses ranging from 1.7 to beyond 4 TeV. In light of these results the bounds from Indirect Detection on wino-like dark matter should be revisited.Comment: 49 pages, 15 figure

The First Deal: The Division of Founder Equity in New Ventures

This paper examines the division of founder shares in entrepreneurial ventures, focusing on the decision of whether or not to divide the shares equally among all founders. To motivate the empirical analysis we develop a simple theory of costly bargaining, where founders trade off the simplicity of accepting an equal split, with the costs of negotiating a differentiated allocation of founder equity. We test the predictions of the theory on a proprietary dataset comprised of 1,476 founders in 511 entrepreneurial ventures. The empirical analysis consists of three main steps. First we consider determinants of equal splitting. We identify three founder characteristics –idea generation, prior entrepreneurial experience and founder capital contributions – regarding which greater team heterogeneity reduces the likelihood of equal splitting. Second, we show that these same founder characteristics also significantly affect the share premium in teams that split the equity unequally. Third, we show that equal splitting is associated with lower pre-money valuations in first financing rounds. Further econometric tests suggest that, as predicted by the theory, this effect is driven by unobservable heterogeneity, and it is more pronounced in teams that make quick decisions about founder share allocations. In addition we perform some counterfactual calculations that estimate the amount of money ‘left on the table’ by stronger founders who agree to an equal split. We estimate that the value at stake is approximately 10% of the firm equity, 25% of the average founder stake, or $450K in net present value.