A methodology to create robust job rotation schedules

This research proposes a methodology for developing robust job rotation schedules to reduce the likelihood of low back injury due to lifting. We consider settings that have uncertain task demands and different worker profiles in order to simulate real settings. We begin by considering deterministic versions of the problem and solve these using mathematical programming. Because mathematical programming cannot be readily applied to stochastic versions of the problem, heuristic solution methods are developed. The effectiveness of these methods is demonstrated by comparing the results with provably optimal solutions from the deterministic problems and with an enumerative approach that is applied to the stochastic version of the problem. Across the test problems, the proposed heuristics are effective at finding good job rotation solutions. The proposed methods could also be applied to solve other job rotation objectives such as maximizing productivity and reducing exposure to other work environmental factors such as excessive noise.     

The application of the shapiro reaction to the stereoselective synthesis of E-trisubstituted olefins for cation-olefin cyclization by three component coupling

A method is described for the rapid and stereoselective assembly of E-trisubstituted olefins by a convergent process from three components     

Investigation of physical properties of quartz after focused ion beam bombardment

Optical properties (transmission and refractive index) and phase change (from amorphous to crystal) of a commonly used glass, quartz, were investigated before and after focused ion beam (FIB) bombardment with ion energy from 30 to 50 keV. We found different influences of FIB bombardment on the optical properties and chemical structure of the quartz in the wavelength region of visible and near infrared, respectively. The quartz still can be used in the infrared wavelength for conventional optical applications. As an application example, an array of diffractive optical elements (DOEs) was directly fabricated on the quartz by the FIB milling. The measured diffraction efficiency of the DOEs is 83.5%, which is acceptable for practical use.This revised version was published online in March 2005. In the previous version, the published online date was missing     

Effect of carbon dioxide sorption on the phase behavior of weakly interacting polymer mixtures: Solvent‐induced segregation in deuterated polybutadiene/polyisoprene blends

The effect of carbon dioxide (CO₂) sorption on the lower critical solution temperatures of deuterated polybutadiene/polyisoprene blends was determined with in situ small‐angle neutron scattering. CO₂ was a poor solvent for both polymers and exhibited very weak selectivity between the blend components. The sorption of modest concentrations of CO₂, at pressures up to 160 bar, induced phase segregation at temperatures well below the binary‐phase‐separation temperature and caused an increased asymmetry in the lower critical solution temperature curve. The origin of solvent‐induced phase segregation in this weakly interacting polymer blend system was attributed predominantly to an exacerbation of the existing disparity in the compressibility of the components upon CO₂ sorption. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 3114–3126, 2003     

Multiple quantum well mixing and index-guided quantum well heterostructure lasers by MeV ion implantation

In recent years considerable interest has been shown in impurity-induced compositional disordering of III–V compound semiconductor devices, especially in efforts directed towards fabricating index-guided buried heterostructure lasers and other unique photonic and electronic devices. In this work we describe the study of compositional disordering induced by MeV implantation of oxygen and krypton into AlAs-GaAs superlattices and the fabrication of index-guided quantum well heterostructure lasers by MeV oxygen ion implantation.     

A class of nondispersive evolution equations with solitary wave solutions

We present a class of nonlinear evolution equations possessing stable solitary wave solutions with a sech² profile. These equations are related to the Korteweg-de Vries (KdV) and regularised longwave (RLW) equations, but, unlike the latter, are dispersion free in the linear limit.     

A general local-mode theory for high energy polyatomic overtone spectra and application to dichloromethane

A new model is developed to describe the overtone spectra of polyatomic molecules containing XH_n moieties. The infrared absorption is described as corresponding to excitation of localized modes of vibration rather than a set of symmetry allowed combinations of anharmonic normal modes. The possibility of assigning new bands in the more complex regions of the overtone spectra which involve combinations of both stretching and bending modes is examined and illustrated using the overtone spectrum of ammonia. The overtone spectrum of dichloromethane is recorded in the range λ = 9260 Å to λ = 5300 Å, and the CH overtone bands at 8850 Å, 7223 Å, and 6165 Å corresponding to the Δv_CH = 4, 5, and 6 overtones are identified. Specific features of these bands are discussed in detail in relation to the model. The common features and simplicity of the Δv_CH = 4 overtone bands of a series of halomethanes and ethanes are also interpreted in terms of the model.