Low-energy photoelectron transmission through aerosol overlayers

The transmission of low-energy (<1.8eV) photoelectrons through the shell of core-shell aerosol particles is studied for liquid squalane, squalene, and DEHS shells. The photoelectrons are exclusively formed in the core of the particles by two-photon ionization. The total photoelectron yield recorded as a function of shell thickness (1-80nm) shows a bi-exponential attenuation. For all substances, the damping parameter for shell thicknesses below 15nm lies between 8 and 9nm, and is tentatively assigned to the electron attenuation length at electron kinetic energies of ~0.5-1eV. The significantly larger damping parameters for thick shells (> 20nm) are presumably a consequence of distorted core-shell structures. A first comparison of aerosol and traditional thin film overlayer methods is provided

Construction labor and productivity : productivity improvements

Construction productivity has been on the decline in the last decade. Although an important factor in the nation\u27s economy, productivity of construction labor has been given little attention over the years. A review of the literature dealing with construction was performed that revealed the importance of the declining productivity as well as the confusion among construction managers and labor leaders as to what productivity is all about and how it can be improved. It has been found also, that construction labor motivation, which is the most important factor in improving productivity, is almost nonexist. Very few construction companies employ any kind of motivational programs and most of these programs are outdated and inefficient. It is recommended, therefore, that construction companies take immediate action to install motivational programs that are up-to-date and efficient. This paper also examines various ways of improving productivity in construction. The major ones are : (1) Management and unions should work together to establish job security; (2) absenteeism in construction must be controlled; (3) management must establish financial incentives; (4) communication in the construction site must be improved; and (5) management and unions must get themselves seriously involved in productivity bargaining. The paper further concludes that management and unions must work together to improve productivity. The feeling of togetherness, although nonexist , is much needed in construction and much work should be done by both management and unions toward creating this feeling

Engineering Design of Rock Slope Reinforcement Based on Non-Linear Joint Strength Model

Optimum dimensioning of bolts or anchors for the reinforcement of slopes in jointed rock masses, requires compatible strength-deformation data, for both the rock joints and the reinforcing elements. Most types of rock joints behave in non- linear fashion and, thus, realistic modelling can have serious implications in the design, both from the economical and the technical standpoints. This paper will present, briefly, the principles of a constitutive model of joint shear behaviour and a method for optimum bolt or anchor design. The implications of non-linear joint behaviour will be demonstrated with numerical examples. Finally, a case study of slope stabilization, in which the method was adopted, will be reported

Three dimensional four-fermion models - A Monte Carlo study

We present results from numerical simulations of three different 3d four-fermion models that exhibit Z_2, U(1), and SU(2) x SU(2) chiral symmetries, respectively. We performed the simulations by using the hybrid Monte Carlo algorithm. We employed finite size scaling methods on lattices ranging from 8^3 to 40^3 to study the properties of the second order chiral phase transition in each model. The corresponding critical coupling defines an ultraviolet fixed point of the renormalization group. In our high precision simulations, we detected next-to-leading order corrections for various critical exponents and we found them to be in good agreement with existing analytical large-N_f calculations.Comment: 15 pages, 7 figures, and 2 table

Time-resolved velocity map imaging of methyl elimination from photoexcited anisole

To date, H-atom elimination from heteroaromatic molecules following UV excitation has been extensively studied, with the focus on key biological molecules such as chromophores of DNA bases and amino acids. Extending these studies to look at elimination of other non-hydride photoproducts is essential in creating a more complete picture of the photochemistry of these biomolecules in the gas-phase. To this effect, CH3 elimination in anisole has been studied using time resolved velocity map imaging (TR-VMI) for the first time, providing both time and energy information on the dynamics following photoexcitation at 200 nm. The extra dimension of energy afforded by these measurements has enabled us to address the role of πσ* states in the excited state dynamics of anisole as compared to the hydride counterpart (phenol), providing strong evidence to suggest that only CH3 fragments eliminated with high kinetic energy are due to direct dissociation involving a 1πσ* state. These measurements also suggest that indirect mechanisms such as statistical unimolecular decay could be contributing to the dynamics at much longer times

Multiple Transition States and Roaming in Ion-Molecule Reactions: a Phase Space Perspective

We provide a dynamical interpretation of the recently identified `roaming' mechanism for molecular dissociation reactions in terms of geometrical structures in phase space. These are NHIMs (Normally Hyperbolic Invariant Manifolds) and their stable/unstable manifolds that define transition states for ion-molecule association or dissociation reactions. The associated dividing surfaces rigorously define a roaming region of phase space, in which both reactive and nonreactive trajectories can be trapped for arbitrarily long times.Comment: 20 pages, 6 figure

Moneyball applied: Econometrics and the identification and recruitment of elite Australian footballers

The best selling book Moneyball posited a theory on the success of a Major League Baseball franchise that used detailed match data to identify inefficiencies in the market for professional baseball players. These statistics were then exploited to the advantage of that team. An important part of this strategy involved using mathematical techniques to identify which player statistics were most associated with team success, and then using these results to decide which players to recruit. This paper uses a similar approach to analyze elite Australian Football, making use of various types of regression models to identify and quantify the important player statistics in terms of their affect on match outcomes