Dyes as guests in ordered systems: current understanding and future directions

The optical properties of dyes dissolved in liquid crystals have led to their proposed use in a diverse range of practical applications. Such guest–host systems are typically required to fulfil a range of criteria relating to their absorption properties, degree of alignment and stability, but concurrently satisfying these requirements has proven a barrier to their widespread use. In this article, many of the proposed applications and their requirements are discussed, and an outline of some of the most prevalent classes of dye proposed in the context of guest–host systems is given, along with a summary of recent reports of dyes that exhibit thermotropic mesophases. Theoretical approaches to describing the alignment within guest–host systems are outlined, and possible strategies for the future rational design of guest–host systems are discussed

Building momentum for business school curriculum change: Measurable lessons from a pilot course in real business experience

Curriculum change requires thoughtful planning and a willingness to experiment with different modes of content delivery. While many business schools are experimenting, few measure student outcomes against the traditional courses they replace. One element of Butler University\u27s College of Business Administration curriculum revision was a pilot course, Real Business Experience , in which students developed a professional business plan, sought and received funding from a professional level funding panel, and ran their businesses. To determine whether the pilot course was successful in reaching its goal of teaching students about the messiness of business and developing more adaptable and confident business leaders assessment instruments were used to identify student development in both the pilot and traditional courses. The analysis presented in this article suggests that the pilot course utilizing the constructivist approach was successful in achieving its goal, but not always in the ways expected

The Kuroshio Region off Southwest Japan ASUKA 1993-95 Inverted Echo Sounder Data Report

In order to study the time-varying volume and heat transports of the Kuroshio off southwest Japan, a large number of scientists from Japan and a small number from the U.S.A. formed a group called ASUKA. This group carried out a coordinated investigation which was concentrated in time on the years 1993-95, and in space on a 1,000 km segment of a TOPEX/POSEIDON suborbital track running south-southeast from western Shikoku. This report describes the techniques used to process data collected by ten inverted echo sounders (IES) on this 1,000 km line off Japan, as part of the ASUKA study. The University of Rhode Island (URI) was responsible for all the IES\u27s except IES5 and IES8 which were from the Hydrographic Department of the Japanese Maritime Safety Agency (MSA/HD). The URI IES\u27s were deployed from the Training Vessel Keiten-maru in October 1993 and recovered from the same vessel in November 1995. The MSA/HD IES\u27s were deployed from the Survey Vessel Shoyo in July 1993. IES8 was recovered by Shoyo in May 1994, but unfortunately IES5 was not recovered

Sediment and particulate carbon removal by pipe erosion increase over time in blanket peatlands as a consequence of land drainage

Land drainage is common in peatlands. Artificially drained blanket peat catchments have been shown to have a significantly greater soil pipe density than intact catchments. This paper investigates the role of surface land drains in the enhancement of soil piping in blanket peats. The density of piping was found to significantly increase in a linear fashion with the age of the drainage. Thirty-five years after drains were cut, slopes would be expected to have twice the density of soil piping than would an undrained blanket peat catchment. The rate of pipe erosion increases exponentially over time, so that particulate carbon loss from subsurface pipes is greatest where drains are oldest

The Interplay of Magnetic Fields, Fragmentation and Ionization Feedback in High-Mass Star Formation

Massive stars disproportionately influence their surroundings. How they form has only started to become clear recently through radiation gas dynamical simulations. However, until now, no simulation has simultaneously included both magnetic fields and ionizing radiation. Here we present the results from the first radiation-magnetohydrodynamical (RMHD) simulation including ionization feedback, comparing an RMHD model of a 1000 M_sol rotating cloud to earlier radiation gas dynamical models with the same initial density and velocity distributions. We find that despite starting with a strongly supercritical mass to flux ratio, the magnetic field has three effects. First, the field offers locally support against gravitational collapse in the accretion flow, substantially reducing the amount of secondary fragmentation in comparison to the gas dynamical case. Second, the field drains angular momentum from the collapsing gas, further increasing the amount of material available for accretion by the central, massive, protostar, and thus increasing its final mass by about 50% from the purely gas dynamical case. Third, the field is wound up by the rotation of the flow, driving a tower flow. However, this flow never achieves the strength seen in low-mass star formation simulations for two reasons: gravitational fragmentation disrupts the circular flow in the central regions where the protostars form, and the expanding H II regions tend to further disrupt the field geometry. Therefore, outflows driven by ionization heating look likely to be more dynamically important in regions of massive star formation.Comment: ApJ in pres

Molecular Design Parameters of Anthraquinone Dyes for Guest-Host Liquid-Crystal Applications : Experimental and Computational Studies of Spectroscopy, Structure and Stability

A set of five anthraquinone dyes with bis(4-propylphenyl) substituent groups, connected via sulfide or amine linkages at the 1,5-positions or directly at the 2,6-positions, have been studied in solution by UV-vis spectroscopy and electrochemistry, allied with density functional theory calculations of structures, electronic transitions, and redox potentials. The visible transitions and redox potentials are shown to vary with the HOMO and LUMO energies, with the variation in both color and redox stability between the dyes being attributable principally to variations in the HOMOs located mainly on the substituents and outer anthraquinone rings. The calculated molecular structures and visible transition dipole moments are shown to vary subtly with substituent, giving variations in the molecular aspect ratios, minimum moment of inertia axes, and transition dipole moment vector orientations that can rationalize the alignment trends reported in the literature for such anthraquinone dyes in liquid crystal hosts, showing why 1,5-disulfide and 2,6-diphenyl substituents give better designs than 1,5-diamine substituents. The computational approaches reported here are shown to give good matches with experimental trends, indicating that they may be used more generally to aid the rational molecular design of dyes for applications as guests in liquid crystal hosts

Velocity Field Statistics in Star-Forming Regions. I. Centroid Velocity Observations

The probability density functions (pdfs) of molecular line centroid velocity fluctuations and fluctuation differences at different spatial lags are estimated for several nearby molecular clouds with active internal star formation. The data consist of over 75,000 $^{13}$CO line profiles divided among twelve spatially and/or kinematically distinct regions. Although three regions (all in Mon R2) appear nearly Gaussian, the others show strong evidence for non-Gaussian, often nearly exponential, centroid velocity pdfs, possibly with power law contributions in the far tails. Evidence for nearly exponential centroid pdfs in the neutral HI component of the ISM is also presented, based on older optical and radio observations. These results are in contrast to pdfs found in isotropic incompressible turbulence experiments and simulations. Furthermore, no evidence is found for the scaling of difference pdf kurtosis with Reynolds number which is seen in incompressible turbulence, and the spatial distribution of high-amplitude velocity differences shows little indication of the filamentary appearance predicted by decay simulations dominated by vortical interactions. The variation with lag of the difference pdf moments is presented as a constraint on future simulations.Comment: LaTeX, 23 pages, with 15 Figures included separately as gif image files. Refereed/revised version accepted to the Astrophysical Journal. A complete (but much larger) postscript version is available from http://ktaadn.gsfc.nasa.gov/~miesc