An artificial compressibility based fractional step method for solving time dependent incompressible flow equations. Temporal accuracy and similarity with a monolithic method

In this note, an artificial compressibility based fractional step method is analysed against a monolithic scheme for solving incompressible flow equations. The artificial compressibility (AC) procedure presented in this paper is stabilized via a characteristic based split (CBS), and thus it is referred to as the AC-CBS method. The monolithic method used for comparison in the present study is the pressure stabilized Petrov–Galerkin (PSPG) method. It is shown that the AC-CBS and PSPG procedures are identical in structure, except for the stabilization parameters. For unsteady problems, a dual time stepping algorithm is employed in the AC-CBS scheme. Unlike classical fractional step methods, this dual time stepping mechanism circumvents the temporal pressure splitting error, and thus provides the anticipated temporal accuracy. The temporal accuracy of the AC-CBS method is demonstrated via a standard benchmark problem. Up to fourth order time accurate schemes are introduced for a thorough analysis of the AC-CBS scheme.     

Effect of incident angle in spectral ellipsometry on composition control during molecular beam epitaxial growth of HgCdTe

The effect of incident angle in spectral ellipsometry (SE) on composition control of Hg_1−xCd_xTe grown by molecular beam epitaxy (MBE) was investigated. Although a small uncertainty in the incident angle tends to have a significant impact on the ellipsometric data, and therefore the composition data, it was found that the incident angle uncertainty could be corrected in the SE model calculation, resulting in an “optimized” incident angle that would give the best fit between measured and calculated ellipsometric data. Experimental data supporting this simple corrective or optimization procedure for the incident angle are presented.     

Comparison of immunofiltration assay of plasma D-dimer with diagnostic imaging in deep vein thrombosis

This prospective study was designed to assess the diagnostic sensitivity, specificity and negative predictive value of the NycoCard D-dimer plasma immunofiltration assay in patients with suspected deep vein thrombosis (DVT) confirmed by ultrasonography/venography. 84 medical patients were recruited: 43 patients (51%) had proven venous thrombosis, 33 by venography and 10 by ultrasonography. The sensitivity of NycoCard D-dimer in patients with DVT was 95.3%, the specificity was 22.0% and the negative predictive value was 81.8%. An algorithm including the NycoCard D-dimer test for the acute management of DVT is proposed. This would enable low-risk patients to be discharged early from hospital, without imaging or anticoagulant therapy.     

Intergrowth of crystal structures in “β-alumina”

Crystallites from shattered and ion-beam-etched specimens of β-alumina ceramics have been examined in the electron microscope and shown to consist of disordered intergrowths of a variety of structural types.     

Preparation of ZnSe light-emitting diodes by metalorganic chemical vapor deposition using trisdimethylaminoarsine as a p-type doping source

Trisdimethylaminoarsine was used in atmospheric-pressure metalorganic chemical vapor deposition growth of ZnSe on GaAs. The metalorganic precursors employed for ZnSe growth were diethylzinc and diethylselenide, and ethyliodide was used as then-type dopant. P-on-n light emitting diode (LED) structures were prepared, and molecular beam epitaxially deposited HgTe layers were used as ohmic contacts to the p-type ZnSe. Blue LEDs were fabricated on p-on-n samples. Preliminary LED data and the material characterization data are presented.     

Colour fastness to industrial laundering: an international inter‐laboratory trial of the proposed ISO 105‐C12 test procedure†

A new laboratory single‐wash test procedure that describes four test conditions, ISO 105‐C12, has been developed to assess the colour fastness of textiles under industrial laundry conditions. Following an international trial, the intra‐laboratory repeatability and the inter‐laboratory reproducibility of the test were found to be fully acceptable. The results obtained under two of the laboratory test conditions were compared with five washes in an industrial laundry under similar conditions and acceptable correlations were found.     

Efficient uncertainty analyses using fast probability integration

Fast probability integration (FPI) algorthms are adapted, extended and used to perform nuclear engineering uncertainty analyses. Methods are presented to improve the efficiency and precision of FPI for frequently encountered input distributions, to permit quick estimates of extreme model output quantiles and to provide appropriate sensitivity and uncertainty importance measures. Advantages and disadvantages of FPI as a stand-alone method are explored in two demonstration applications. FPI is first applied to estimate extreme (0.95, 0.99, 0.999 and 0.9999) quantiles of the frequency of a dominant station blackout accident. Sensitivity measures are quantified to indicate how the relative importance of each model input changes at progressively more extreme output quantiles. FPI is next applied to analyze uncertainties in fire damage times predicted by . Alternative FPI-based uncertainty importance measures are compared and shown to consistently rank the input contributions to the output uncertainty. FPI results are compared with results obtained from Monte Carlo sampling to demonstrate the computational advantage that clearly favors FPI, especially at the more extreme output quantiles.In a third application, Latin hypercube sampling (LHS) is combined with FPI to determine extreme quantiles of peak cladding temperature during the blowdown phase of a large-break loss of coolant accident as modeled by . The 0.95 quantile peak cladding temperature is reproducibly determined to within 2 K in one LHS-FPI iteration, which is based on only 21 runs. To demonstrate convergence for a more extreme case, LHS-FPI is also applied to estimate the 0.999 quantile peak cladding temperature. In each LHS-FPI iteration a final code run is performed to assure that the code-calculated peak cladding temperature agrees with that predicted by LHS-FPI at the most probable point. Importance measures are quantified at this point to identify dominant input-output relationships. Compared with past code scaling, applicability and uncertainty (CSAU) analyses, LHS-FPI offers a significant reduction in the number of best-estimate code runs required while providing additional checks and insights.     

Seeing and hearing rotated faces: influences of facial orientation on visual and audiovisual speech recognition

It is well-known that facial orientation affects the processing of static facial information, but similar effects on the processing of visual speech have yet to be explored fully. Three experiments are reported in which the effects of facial orientation on visual speech processing were examined using a talking face presented at 8 orientations through 360 degrees. Auditory and visual forms of the syllables /ba/, /bi/, /ga/, /gi/, /ma/, /mi/, /ta/, and /ti/ were used to produce the following speech stimulus types: auditory, visual, congruent audiovisual, and incongruent audiovisual. Facial orientation did not affect identification of visual speed per se or the near-perfect accuracy of auditory speech report with congruent audiovisual speech stimuli. However, facial orientation did affect the accuracy of auditory speech report with incongruent audiovisual speech stimuli. Moreover, the nature of this effect depended on the type of incongruent visual speech used. Implications for the processing of visual and audiovisual speech are discussed.     

A picture is worth a thousand words: A content analysis of Facebook profile photographs

This research examines identity construction and gender roles in social networking sites by studying and comparing the profile photographs of male and female Facebook users. Specifically, the number of photos in the profile album and the content of the main profile picture are studied by coding specific pictures, and determining if the content and amount of profile pictures differ significantly by gender. Participants include male and female Facebook users between the ages of 18 and 23 who are currently enrolled in a college or university. Profile pictures tended to be inactive, posed, appropriate, and only including the subject. The content and amount of Facebook profile photographs also did not significantly vary by gender. Implications of these findings, as well as suggestions for future research, are discussed.