Film-pore diffusion modeling for the sorption of metal ions from aqueous effluents onto peat

The sorption of three metal ions, namely, copper, nickel and lead onto sphagnum peat moss has been studied using an agitated batch sorber system. The equilibrium isotherms were determined and kinetic runs were performed over a range of concentrations for each metal ion. A film-pore diffusion mass transfer model has been developed based on a single effective diffusion coefficient for each system. Error analysis of the experimental and theoretical data indicated relatively large errors at low initial metal ion concentrations. Therefore the model was modified to introduce a surface coverage concentration dependent effective diffusivity to account for a contribution from surface diffusion.     

Hindered settling of organic pigment dispersions in hydrocarbon liquids

A modified Steinour hindered settling method has been developed for the study of dispersed organic pigment species containing a large proportion of associated immobile liquid. These species are termed flow units with effective volumes and densities different from those of the pigment itself. The effective volume and density are calculated from the final sediment volume fraction after correction (if practicable) by an appropriate packing factor. The mean flow unit diameter (or a size parameter) can then be estimated. The present method has been satisfactorily tested using formalin-fixed yeast cells as model flow units which can be sized readily by optical microscopy. Data for organic pigment dispersions compare well with their appearance under the optical microscope. Various uses of simplified versions of the present technique in studies of dispersibility and dispersion stability of organic pigments are described and exemplified using mainly copper phthalocyanine pigments in hydrocarbon solvents.     

Diatoms abound in ice-covered Lake Erie: An investigation of offshore winter limnology in Lake Erie over the period 2007 to 2010

The limnology of offshore Lake Erie during periods of extensive (> 70%) ice cover was examined from ship borne sampling efforts in 2007 to 2010, inclusive. Dense and discrete accumulations of the centric filamentous diatom Aulacoseria islandica (> 10 μg Chl-a/L) were located in the isothermal (< 1 °C) water column directly below the ice and only detectable in the ship wake; viable phytoplankton were also observed within ice. Evidence from these surveys supports the notions that winter blooms of diatoms occur annually prior to the onset of ice cover and that the phytoplankton from these blooms are maintained in the surface waters of Lake Erie and reduce silicate concentrations in the lake prior to spring. The mechanisms by which high phytoplankton biomass rise at this time of year requires further investigation, but these winter blooms probably have consequences for summer hypoxia and how the lake responds to climate change.     

Filling the ‘white ribbon’ – a multisource seamless digital elevation model for Lizard Island,northern Great Barrier Reef

Hydrographers have traditionally referred to the nearshore area as the ‘white ribbon’ area due to the challenges associated with the collection of elevation data (elevation hereafter refers to both topography and bathymetry) in this highly dynamic transitional zone between terrestrial and marine environments. Accordingly, available information in this zone is typically characterized by a range of data sets from disparate sources. In this article, we propose a framework to fill the white ribbon area of a coral reef system by integrating multiple elevation data sets acquired by a suite of remote-sensing technologies into a seamless digital elevation model (DEM). A range of data sets are integrated, including field-collected global positioning system (GPS) elevation points, topographic and bathymetric light detecting and ranging (lidar), single and multibeam echosoundings, nautical charts, and bathymetry derived from optical remote-sensing imagery. The proposed framework ranks data reliability internally, thereby avoiding the requirements to quantify absolute error and results in a high-resolution, seamless product. Nested within this approach is an effective spatially explicit technique for improving the accuracy of bathymetry estimates derived empirically from optical satellite imagery through modelling the spatial structure of residuals. The approach was applied to data collected on and around Lizard Island in northern Australia. Collectively, the framework holds promise for filling the white ribbon zone in coastal areas characterized by similar data availability scenarios.     

Shape detection with vision: implementing shape grammars in conceptual design

Despite more than 30 years of research, shape grammar implementations have limited functionality. This is largely due to the difficult problem of subshape detection. Previous research has addressed this problem analytically and has proposed solutions that directly compare geometric representations of shapes. Typically, such work has concentrated on shapes composed of limited geometry, for example straight lines or parametric curves, and as a result, their application has been restricted. The problem of general subshape detection has not been resolved. In this paper, an alternative approach is proposed, in which subshape detection is viewed as a problem of object recognition, a sub-domain of computer vision. In particular, a general method of subshape detection is introduced based on the Hausdorff distance. The approach is not limited in terms of geometry, and any shapes that can be represented in an image can be compared according to the subshape relation. Based on this approach, a prototype shape grammar system has been built in which the geometry of two-dimensional shapes is not restricted. The system automates the discovery of subshapes in a shape, enabling the implementation of shape rules in a shape grammar. Application of the system is illustrated via consideration of shape exploration in conceptual design. The manipulations of sketched design concepts are formalised by shape rules that reflect the types of shape transformations employed by designers when sketching.     

Does drinking lead to sex? Daily alcohol–sex behaviors and expectancies among college students.

A within-person multilevel approach was used to model the links between alcohol use and sexual behavior among first-year college students, using up to 14 days of data for each person with occasions (Level 1, N = 2879 days) nested within people (Level 2, N = 218 people; 51.4% male). Between-persons (Level 2) effects were gender, relationship status, person means of alcohol use, and alcohol-sex expectancies for sexual affect and sexual drive. Within-person (Level 1) effects were weekend days, number of drinks consumed, and the interaction between drinks consumed and alcohol-sex expectancies. Independent of average alcohol use, consuming more drinks on a given day was associated with a greater likelihood of oral sex and with experiencing more positive consequences of sex that day. Significant Alcohol Use × Alcohol-Sex Expectancies interactions were found for oral sex and total sex behaviors, indicating that individuals with more positive expectancies were more likely to have sex after drinking. The negative association between drinks and condom use was at a trend level of significance. Results support the potential for promoting sexual health by focusing on cross-behavior expectancies among late adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associations among religiousness, social attitudes, and prejudice in a national random sample of American adults.

Psychologists have devoted considerable theoretical and empirical attention to the scientific study of social attitudes and prejudice. Most of these studies were conducted with relatively small, nonrepresentative samples of college students. In this study, the authors analyzed self-report data from a random probability sample with over 1500 American adults. Participants answered questions about their religiousness, right-wing authoritarianism (RWA), political ideology, demographic characteristics, and attitudes toward persons in historically disadvantaged social groups (i.e., ethnic minorities and homosexual individuals). In support of the selective intolerance hypothesis, general religiousness was associated with less accepting attitudes toward homosexuals and negligibly with general racial prejudice. These associations remained when controlling for some other known individual differences in prejudice. The authors tentatively conclude that general religiousness is not associated with universal acceptance of others. Rather, general religiousness appears to be linked with selective self-reported intolerance toward persons perceived to behave in a manner inconsistent with some traditional religious teachings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)