A high order method for the numerical integration of the one-dimensional Schrödinger equation

A sixth order method is developed for the approximate numerical integration of the one-dimensional Schrödinger equation. Numerical results obtained for the integration of both the eigenvalue and the phase shift problems show that this new method is generally superior to the widely used Numerov method.     

MHD free convection flow past an accelerated vertical plate

The effect of a uniform transverse magnetic field on the free convection flow of an electrically conducting fluid past an infinite vertical plate for both the classes of impulsive as well as uniformly accelerated motion of the plate is discussed. In this analysis, the magnetic lines of force are assumed to be fixed relative to the plate. Laplace transform technique has been used to obtain the expressions for the velocity field and skin-friction for both cases. It is found that the effect of the magnetic field is to increase the velocity field in both cases.     

MHD flow past a steadily moving infinite vertical porous plate with constant heat flux

A study of the flow of an electrically conducting fluid past a steadily moving vertical infinite plate is presented. It is assumed that there is a constant heat flux and constant suction at the plate. Presence of induced magnetic field is also taken into account. The velocity profiles, the temperature profiles, the induced magnetic field, the skin-friction, the Nusselt number and the current density are shown on graphs. The results are discussed.     

ACOUSTIC FLOW INSTRUMENTS FOR SOLID/GAS FLOWS

Two nonintrusive acoustic flow sensing techniques are reported. One technique, passive in nature, simply measures the bandpassed acoustic noise level produced by particle/particle and particle/wall collisions. The noise levels, given in true root-mean-square voltages or in autocorrelations, show a linear relationship to particle velocity but increase with solid concentration. Therefore, the passive technique requires calibration and a separate measure of solid concentration before it can be used to monitor particle velocity. The second technique is based on the active cross-correlation principle. It measures particle velocity directly by correlating flow-related signatures at two sensing stations. The velocity data obtained by this technique are compared with measurements by a radioactive-particle time-of-flight (TOF) method. A multiplier of 1.53 is required to bring the acoustic data into agreement with the radioactive TOF result. The difference may originate from the difference in flow fields where particles are detected. The radioactive method senses particles mainly in the turbulent region and essentially measures average particle velocity across the pipe, while the acoustic technique detects particles near the pipe wall, and measures the particle velocity in the viscous sublayer. Both techniques were tested in flows of limestone and air and glass beads (1 mm) and air at the Argonne National Laboratory Solid/Gas Flow Test Facility. The test matrix covered solid velocities of 20 to 30 m/s in a 2-in. pipe and solid-to-gas loading ratios of 6 to 22.     

Two-step methods for the numerical solution of the Schrödinger equation

A new two-step exponentially-fitted formula is derived and applied to the Schrödinger equation. The new method is found to significantly more accurate than the standard methods, for large values of the energy.     

Studying the effect of perceived hedonic mobile device quality on user experience evaluations of mobile applications

When people interact with digital artefacts they perceive their pragmatic and hedonic qualities. In the case of interacting with mobile devices and applications, users seek utility as they try to satisfy certain needs, but at the same time they have certain feelings and emotions when, for example, they feel attached to their personal phone and/or trust its brand. Due to this strong relation between users and mobile devices a significant problem occurs when researchers want to evaluate the user experience of a mobile application in laboratory settings: the selection of an appropriate mobile device. Towards this end, this paper aims to unveil the effect of perceived hedonic quality of a mobile device on the user experience evaluation results of an application. Our results show that the perceived hedonic quality of a mobile device significantly affected the perceived pragmatic quality of the application, but not the hedonic one.     

System Identification for a Miniature Helicopter at Hover Using Fuzzy Models

The objective of this paper is to present a system identification method suitable for miniature rotorcrafts under hovering. The proposed model to be identified is a Takagi-Sugeno fuzzy system, representing translational and rotational velocity dynamics. For parameter estimation of the Takagi-Sugeno system a classical Recursive Least Squares (RLS) algorithm is used, which allows identification to take place on-line since parameter updates are produced whenever a new measurement becomes available. The validity of this approach is tested using the X-Plane ^© flight simulator. Data obtained offer justification for the applicability of the approach in real-time applications.     

Total ozone column measurements using an ultraviolet multi-filter radiometer

We have developed and used a method to retrieve total ozone column (TOC), from Ultraviolet Multi-filter Rotating Shadowband Radiometer (UVMFR) measurements in combination with radiative transfer model calculations. Look-up tables of ratios of the direct solar irradiance at (DI) 305 and 325nm in terms of TOC, solar zenith angle, and aerosol optical depth (AOD) have been constructed and compared with TOC retrievals estimated directly from UVMFR irradiance measurements. Sensitivity analysis of the influence of AOD on the calculated TOC has been investigated and found to be 1 Dobson unit per 0.1 change in AOD. We also examined the impact of ozone effective temperature on the TOC retrieval and found that it leads to a 0.9% change in TOC per K. UVMFR direct irradiance measurements in Athens, Greece, during the period July 2009–May 2014 were used to create a time series of high-temporal-frequency measurements (1 min for cloudless conditions) of TOC, which facilitated an analysis of the diurnal variation of TOC. Comparison of the TOC retrievals from the UVMFR with co-located and synchronous daily TOC retrievals from a Brewer MKIV spectrophotometer showed very good agreement (correlation coefficient 0.98). Daily TOC retrievals from the UVMFR were within ±3% compared with the ones measured by the Ozone Monitoring Instrument overpasses on board the Aura satellite.     

The spectroelectrochemical, magnetic, and structural characterization of reduced hexaazatriphenylenehexacarbonitrile, HAT(CN)6

The cyanoazacarbon, hexaazatriphenylenehexacarbonitrile, or HAT(CN)₆, is readily reduced and the spectroelectrochemical properties associated with the multiple reductions are described. The singly reduced radical monoanion forms stable salts and we report the crystal structure and magnetic properties for the tetrabutylammonium salt. [Tetra-n-butylammonium] [HAT(CN)₆] behaves ferromagnetically below 3 K and follows Curie Law behavior at higher temperatures after correction for Pauli-type susceptibility. The room temperature conductivity of the powdered salt is 3.8 × 10⁻⁸ S/cm. The crystal structure shows closely bound pairs of radical anions with slip-stacking of these pairs to form a staircase, features that elucidate the observed properties. Thin films of HAT(CN)₆ were found to support negative charge transport by electron time-of-flight measurements, yielding electron mobilities of 10⁻⁴ cm²/Vs at room temperature.     

Polar fluid through a porous medium

Summary An analysis of the steady flow of a polar fluid through a porous medium bounded by an infinite plate by using the generalized Forchheimer's model is considered. The velocity profiles are shown for different values of the permeability parameter.