A study of the photocatalytic effects of aqueous suspensions of platinized semiconductor materials on the reaction rates of candidate redox reactions

The effectiveness of powdered semiconductor materials in photocatalyzing candidate redox reactions was investigated. The rate of the photocatalyzed oxidation of cyanide at platinized TiO2 was studied. The extent of the cyanide reaction was followed directly using an electroanalytical method (i.e. differential pulse polarography). Experiments were performed in natural or artificial light. A comparison was made of kinetic data obtained for photocatalysis at platinized powders with rate data for nonplatinized powders

Household characteristics and consumption behaviour: a nonparametric approach

In this paper we apply nonparametric methods in order to discuss sorne empirical aspects of household consumption behaviour. First, we study the differences in the consumption behaviour between household types. We find that, except for food, there are no elear significant differences. Secondly, we derive the functional form for the food Engel curve, using specification tests consistent in the direction of nonparametric alternatives. Finally, we use this specification to discuss the misleading conelusions that could be reached from a mechanic interpretation of the rejection of Hausman's test, when applied to test the exogeneity of expenditure. The data is obtained from the Spanish Expenditure Survey 1980-81 and 1990-91

The optical and near-infrared properties of nearby groups of galaxies

We present a study of the optical (BRI) and near-infrared (JHK) luminosity fuctions (LFs) of the GEMS sample of 60 nearby groups of galaxies between 0<z<0.04, with our optical CCD photometry and near-IR photometry from the 2MASS survey. The LFs in all filters show a depletion of galaxies of intermediate luminosity, two magnitudes fainter than L*, within 0.3 R{500} from the centres of X-ray faint groups. This feature is not as pronounced in X-ray bright gropus, and vanishes when LFs are found out to R{500}, even in the X-ray dim groups. We argue that this feature arises due to the enhanced merging of intermediate-mass galaxies in the dynamically sluggish environment of low velocity-dispersion groups, indicating that merging is important in galaxy evolution even at z~0.Comment: to appear in the proceedings of the ESO workshop "Groups of Galaxies in the Nearby Universe", Santiago, Dec 5-9, 2005. Eds. I. Saviane, V. Ivanov, & J. Borissova (Springer Verlag); 5 page

Weather on Other Worlds. IV. Hα\alpha emission and photometric variability are not correlated in L0−-T8 dwarfs

Recent photometric studies have revealed that surface spots that produce flux variations are present on virtually all L and T dwarfs. Their likely magnetic or dusty nature has been a much-debated problem, the resolution to which has been hindered by paucity of diagnostic multi-wavelength observations. To test for a correlation between magnetic activity and photometric variability, we searched for H$\alpha$ emission among eight L3$-$T2 ultra-cool dwarfs with extensive previous photometric monitoring, some of which are known to be variable at 3.6 $\mu$m or 4.5 $\mu$m. We detected H$\alpha$ only in the non-variable T2 dwarf 2MASS J12545393$-$0122474. The remaining seven objects do not show H$\alpha$ emission, even though six of them are known to vary photometrically. Combining our results with those for 86 other L and T dwarfs from the literature show that the detection rate of H$\alpha$ emission is very high (94$\%$) for spectral types between L0 and L3.5 and much smaller (20$\%$) for spectral types $\ge$L4, while the detection rate of photometric variability is approximately constant (30$\%-$55$\%$) from L0 to T8 dwarfs. We conclude that chromospheric activity, as evidenced by H$\alpha$ emission, and large-amplitude photometric variability are not correlated. Consequently, dust clouds are the dominant driver of the observed variability of ultra-cool dwarfs at spectral types at least as early as L0.Comment: 12 pages, 4 figures, accepted for publication in Ap

Introduction to the Ignatian Pedagogical Paradigm: An Online Course for Librarians

This article discusses the development and delivery of a three-week asynchronous online course in Jesuit history, education, and the Ignatian Pedagogical Paradigm (IPP) for librarians working in Association of Jesuit Colleges and University (AJCU) institutions. Created by two instruction librarians and one instructional designer from a pair of AJCU institutions, the course explores incorporating the IPP—a contemplative learning model—into a one-shot, single class library instruction session. Included is a practical description of the development, revision, marketing, and success of the online course, along with a list of the class contents. Over three course offerings in 2017 and 2018, thirty-one participants discussed readings and videos, and shared ideas about their current teaching practices. They reflected on how the IPP, or at least some elements of it, might become part of their teaching, despite the time and content constraints. Other topics included the Association of College and Research Libraries (ACRL) “Framework for Information Literacy in Higher Education,” critical librarianship, and social justice. The intent of the article is to raise awareness of the course for interested librarians and to offer guidance to anyone working to develop an online course related to Ignatian pedagogy and teaching

Thermal power systems small power systems applications project. Decision analysis for evaluating and ranking small solar thermal power system technologies. Volume 1: A brief introduction to multiattribute decision analysis

The principal concepts of the Keeney and Raiffa approach to multiattribute decision analysis are described. Topics discussed include the concepts of decision alternatives, outcomes, objectives, attributes and their states, attribute utility functions, and the necessary independence properties for the attribute states to be aggregated into a numerical representation of the preferences of the decision maker for the outcomes and decision alternatives

A theoretical model for the cross spectra between pressure and temperature downstream of a combustor

A theoretical model developed to calculate pressure-temperature cross spectra, pressure spectra, temperature spectra and pressure cross spectra in a ducted combustion system is presented. The model assumes the presence of a fluctuating-volumetric-heat-release-rate disk source and takes into account the spatial distribution of the steady-state volumetric-heat flux. Using the model, pressure, velocity, and temperature perturbation relationships can be obtained. The theoretical results show that, at a given air mass flow rate, the calculated pressure-temperature cross spectra phase angle at the combustor exit depends on the model selected for the steady-state volumetric-heat flux in the combustor. Using measurements of the phase angle, an appropriate source region model was selected. The model calculations are compared with the data. The comparison shows good agreement and indicates that with the use of this model the pressure-temperature cross spectra measurements provide useful information on the physical mechanisms active at the combustion noise source