Tyre load capacity and energy loss with respect to varying soil support stiffness

An analytical model is developed to predict the tyre deformation and the resultant energy loss due to tyre flexibility relative to various soil stiffnesses ranging from rigid unyielding support to soft soil. The analysis allows for examination of a pneumatic tyre with respect to the wheel load to be carried, the supporting ground rigidity and the rigidity of the tyre casing. The important tyre characteristics in providing for wheel load capability under motion are demonstrated to be the tyre carcass construction, dimension, inflation pressure and the ability of the tyre casing to recover some of the resultant energy losses incurred by the tyre under motion.     

An anti-plane shear problem

We consider an anti-plane shear of an elastic cylinder with a non-convex stored energy function. So, we look for solutions of a non-convex problem of the calculus of variations with Dirichlet boundary conditions. We give sufficient conditions on the boundary data to get existence or non-existence results for this non-convex problem. We also prove some uniqueness results for the relaxed problem associated with the initial problem.     

Autocorrelation model of road roughness

Road surface roughness is the excitation source for the dynamic response of a moving vehicle system. Driving comfort is indicated by either the driver absorbed power level or the vehicle vertical acceleration level. An autocorrelation function model for road roughness is proposed to specify the road surface random characteristics. Subsequently, the power spectral densities (PSDs) for both road roughness and vehicle response, the driver-absorbed power level, are formulated. A road quality index (RQI) in accordance with such energy considerations is defined to catalog the road grade. The laboratory test results show the applicability of the RQI method for road classification using the ISO criteria as a comparison check.     

Large Scale Integrated Photonics for Twenty-First Century Information Technologies

In this paper, we will review research done by the Large-Scale Integrated Photonics group at HP Laboratories, and in particular we will discuss applications of optical resonances in dielectric microstructures and nanostructures to future classical and quantum information technologies. Our goal is to scale photonic technologies over the next decade in much the same way as electronics over the past five, thereby establishing a Moore’s Law for optics.     

Mesoscopic dynamics of diffusion-influenced enzyme kinetics

A particle-based mesoscopic model for enzyme kinetics is constructed and used to investigate the influence of diffusion on the reactive dynamics. Enzymes and enzyme-substrate complexes are modeled as finite-size soft spherical particles, while substrate, product, and solvent molecules are point particles. The system is evolved using a hybrid molecular dynamics-multiparticle collision dynamics scheme. Both the nonreactive and reactive dynamics are constructed to satisfy mass, momentum, and energy conservation laws, and reversible reaction steps satisfy detailed balance. Hydrodynamic interactions among the enzymes and complexes are automatically accounted for in the dynamics. Diffusion manifests itself in various ways, notably in power-law behavior in the evolution of the species concentrations. In accord with earlier investigations, regimes where the product production rate exhibits either monotonic or nonmonotonic behavior as a function of time are found. In addition, the species concentrations display both t(-1/2) and t(-3/2) power-law behavior, depending on the dynamical regime under investigation. For high enzyme volume fractions, cooperative effects influence the enzyme kinetics. The time dependent rate coefficient determined from the mass action rate law is computed and shown to depend on the enzyme concentration. Lifetime distributions of substrate molecules newly released in complex dissociation events are determined and shown to have either a power-law form for rebinding to the same enzyme from which they were released or an exponential form for rebinding to different enzymes. The model can be used and extended to explore a variety of issues related concentration effects and diffusion on enzyme kinetics.     

A Mechanisms and Kinetics Study of Polymeric Thin-Film Deposition in Glow Discharge

Polymeric thin-film deposition in a capacitively coupled rf glow discharge of styrene has been investigated. A kinetic scheme for the polymerization was proposed in which initiation of monomers by electron impact was followed by propagation and termination as in conventional polymerization, the initiation rate constant being a function of electron temperature alone. Four mechanism models were examined, depending on where each reaction step takes place: in the gas phase or on the substrate. Free-radical polymerization was assumed. Experiments were carried out at pressures ranging from 0.25 to 1.05 Torr and at voltages and currents that yielded cold and stable discharges. Substrate temperature was controlled. Deposition rate was determined by weighing. A regression program was used in addition to experimental tests in which substrate temperature was varied. The best approximation to the plasma polymer deposition process was found to be the following model: monomers are activated in the gas phase by electron bombardment and subsequently diffuse to the substrate where they propagate and terminate, adsorption of monomers on the substrate playing an important role. A rate expression relating polymer film deposition rate to the experimental variables is presented.     

STRUCTURE STERIQUE DES COMPOSES CYCLIQUES DU PHOSPHORE. XIII. ETUDE PAR MOMENT DIPOLAIRE DES OXO-2 ET THIO-2 PERHYDRO OXAZAPHOSPHORINES-1,3,2

Abstract

L'étude par moment dipolaire de la conformation de huit perhydro oxazaphosphorines-1,3,2 est décrite. The conformation of eight perhydro 1,3,2-oxazaphosphorines is studied by means of dipole moments.