Effect of thermal treatment on the structure and texture of titania

Anatase and rutile pigments, from two sources (B and T) were thoroughly purified from sulphate and chloride contaminants, thermally treated in the temperature range 150 to 550 ° C, and investigated using thermogravimetric (TG), differential thermal analysis (DTA), X-ray diffraction (XRD), nitrogen and organic vapour adsorption techniques. TG analysis reveals two main dehydration steps, the first results from physically adsorbed water and the second from structural and ligand water. The number of ligand water molecules released through a unit surface area (nm²) is in the range 4.50 to 5.15, being evolved in the temperature range 250 to 300 ° C. Two dehydroxylation endotherms appear for the anatase samples in the temperature range 350 to 420 ° C which seem to arise from the presence of two types of hydroxyls. No transformation from the anatase to rutile sructure occurred in the temperature range investigated. Estimation of crystallite sizes showed a marked increase at temperatures >250 ° C for anatase (B), being greatest for the (101) plane, and >400 ° C for rutile (B), where the three planes (101), (110) and (111) increased distinctly. Maximum anisotropy was observed for the anatase heated at 550 ° C. Nitrogen adsorption data revealed a marked decrease in the specific area and total pore volume by thermal treatment 400 ° C for anatase and 250 ° C for rutile whereby it retains a nearly stable value with an average range of 2.62 nm. The anatase (B) samples are composed of a mixture of both meso- and micropores whereas for rutile (B) microporosity appeared only for the sample heated at 150 ° C, becoming predominantly mesoporous at higher temperatures. Most heated samples exhibited two group sizes in the mesopore range resulting from their existence in the form of particles constituted from a collection of small particulates. The rutile (B) products are generally characterized by possessing a wider pore system than those from anatase. The anatase (T) samples are predominantly microporous at 150 ° C and become mesoporous at 550 ° C — the reverse is true for rutile (T). Cyclohexane and benzene adsorption measure only a fraction of the nitrogen area. Specific interaction (H-bonding) is believed to exist in some cases between the cyclohexane molecules and titania surface hydroxyls, as well as some enhanced adsorption which is believed to occur with benzene adsorbate.     

The effects of mice and pull‐down menus versus command‐driven interfaces on writing

The effects of two different computer user interfaces on the process of writing are examined. English composition students (matched on computer experience) used a computer and keyboard (either with function keys or with a mouse) to write essays during their English classes. Essays generated using either a mouse or command‐driven interface were compared across different stages of writing. The impact of using a mouse versus command‐driven interface is described by analyzing the differences in the process used to create the essays and the quality of the essays produced by each group. Results indicate that students who used the command‐driven interface scored better on organization of the paper, creativity, number of supporting arguments, grammar/spelling, and letter grade than did their mouse counterparts, as perceived by graders. However, there were no significant differences between the two interface conditions on any grammatical indices.     

Software Development Effort Estimation: Formal Models or Expert Judgment?

Which is better for estimating software project resources: formal models, as instantiated in estimation tools, or expert judgment? Two luminaries, Magne Jørgensen and Barry Boehm, debate this question.     

The synthesis and reactivity of 3 beta-(2-alkynylsulfonyl)- and 3 beta-(2-alkynylsulfonylmethyl) androst-5-en-17-ones as inhibitors of glucose-6-phosphate dehydrogenase

3 beta-(Hexadec-2-ynylsulfonyl)androst-5-en-17-one, 2c, was designed as an analog of dehydroepiandrosterone sulfatide 1c, a potent, natural inhibitor of glucose-6-phosphate dehydrogenase (G6PDH). Nucleophilic substitution of 1-bromo hexadec-2-yne 11 with 3 beta-mercaptoandrost-5-en-17-one followed by oxidation afforded 2c. The propargylic sulfone 2c may tautomerize to the electrophilic allenic sulfone 3a and thus function as a masked affinity label of the steroidal binding site of G6PDH. Since 2c demonstrated low potency as an inhibitor of G6PDH, a sulfonylmethyl analog 4b was also designed and synthesized. Synthesis of 4b began by methylenation of androst-5-en-3,17-dione 17-ketal 6 with the Tebbe reagent, to yield the 3-methyleneandrost-5-ene 7. Hydroboration, followed by oxidation, gave a mixture of 3 alpha- and 3 beta-hydroxymethyl isomers 8a and 8b, respectively. The 3 beta alcohol 8b was converted to the thiol 10. Alkylation of 10 with 1-bromo-2-hexadecyne 11, followed by selective oxidation, gave the desired acetylenic sulfone 4b. Insertion of the methylene in 4a and 4b significantly increased their G6PDH inhibitory properties over the initial compounds, 2b and 2c.     

The electric resistivity of compacts of graphite intercalation compounds with antimony pentafluoride and with antimony pentachloride

The electric resistivities were measured for textured compacts of the intercalation compounds of graphite with SbF₅ and with SbCl₅. Starting materials were coarse flakes of natural graphite and graphite foils (0.35 and 2 mm thick). First stage compounds and mixtures of first and second stage compounds were studied. The resistivities of the compacts from flakes were strongly pressure dependent, maximum conductivity was not yet reached at 600 bar. The resistivities of preparations from graphite foils were much less pressure dependent. The resistivity of the foils decreased to 36 × 10^?8 Ωm, that is 3–4% of the resistivity of the parent foils. In general, the intercalation compounds with SbF₅ showed somewhat higher resistivities than the SbCl₅ compounds. This seems to be caused by formation of an insulating layer on the surface of the particles due to partial fluorination of carbon atoms with SbF₅. CF bonds were detected by IR spectroscopy and by XPS. The first stage SbF₅ compound is formed already at room temperature, contrary to literature reports, provided sufficient time is given.     

Characterization of fecal concentrations in human and other animal sources by physical,culture-based,and quantitative real-time PCR methods

The characteristics of fecal sources, and the ways in which they are measured, can profoundly influence the interpretation of which sources are contaminating a body of water. Although feces from various hosts are known to differ in mass and composition, it is not well understood how those differences compare across fecal sources and how differences depend on characterization methods. This study investigated how nine different fecal characterization methods provide different measures of fecal concentration in water, and how results varied across twelve different fecal pollution sources. Sources investigated included chicken, cow, deer, dog, goose, gull, horse, human, pig, pigeon, septage and sewage. A composite fecal slurry was prepared for each source by mixing feces from 6 to 22 individual samples with artificial freshwater. Fecal concentrations were estimated by physical (wet fecal mass added and total DNA mass extracted), culture-based (Escherichia coli and enterococci by membrane filtration and defined substrate), and quantitative real-time PCR (Bacteroidales, E. coli, and enterococci) characterization methods. The characteristics of each composite fecal slurry and the relationships between physical, culture-based and qPCR-based characteristics varied within and among different fecal sources. An in silico exercise was performed to assess how different characterization methods can impact identification of the dominant fecal pollution source in a mixed source sample. A comparison of simulated 10:90 mixtures based on enterococci by defined substrate predicted a source reversal in 27% of all possible combinations, while mixtures based on E. coli membrane filtration resulted in a reversal 29% of the time. This potential for disagreement in minor or dominant source identification based on different methods of measurement represents an important challenge for water quality managers and researchers.     

Data processing and law enforcement access to information systems at EU level

EU Agencies and Information Systems collect and exchange personal data with Member States but also between each other. In this context, law enforcement agencies such as Europol increasingly get access to data originally serving other purposes. Europol already has access to the Visa-Information System; plans to allow the access to Eurodac also exist. The rules regulating this exchange are so far not harmonised. The article illustrates the existing exchange and access possibilities in light of the EU data protection reform.     

Pressure-modulated differential scanning calorimetry. An approach to the continuous, simultaneous determination of heat capacities and expansion coefficients

A new method is described that permits the continuous and synchronous determination of heat capacity and expansibility data. We refer to it as pressure-modulated differential scanning calorimetry (PMDSC), as it involves a standard DSC temperature scan and superimposes on it a pressure modulation of preselected format. The power of the method is demonstrated using salt solutions for which the most accurate heat capacity and expansibility data exist in the literature. As the PMDSC measurements could reproduce the parameters with high accuracy and precision, we applied the method also to an aqueous suspension of multilamellar DSPC vesicles for which no expansibility data had been reported previously for the transition region. Excellent agreement was obtained between data from PMDSC and values from independent direct differential scanning densimetry measurements. The basic theoretical background of the method when using sawtooth-like pressure ramps is given under Supporting Information, and a complete statistical thermodynamic derivation of the general equations is presented in the accompanying paper.     

Mitochondrial bioelectrocatalysis for biofuel cell applications

Mitochondria modified electrodes have been developed and characterized that utilize whole mitochondria isolated from tubers and immobilized within a quaternary ammonium modified Nafion membrane on a carbon electrode that can oxidize pyruvate and fatty acids. Detailed characterization of the performance of these mitochondria modified electrodes has been accomplished by coupling the mitochondria-based bioanode with a commercial air breathing cathode in a complete pyruvate/air biofuel cell. The studies included the effect of fuel (pyruvate) concentration, mitochondria lysing, temperature and pH on the performance of the mitochondria catalyzed, pyruvate/air biofuel cell. Effect of oxygen and cytochrome c oxidase inhibitors on biofuel cell performance has allowed us to further understand the mechanism of electron transfer with the carbon electrode.     

ASSØCA: FORTRAN IV program for Williams and Lambert Association analysis with printed dendrograms

A general-purpose computer program implementing Williams and Lambert's method of association analysis is documented. The method embodies a hierarchical-divisive-monothetic strategy for the numerical classification of multiattribute, binary-coded data sets. The main user-controlled options permit a selection from among two different association coefficients and three termination criteria; employment of Yates' correction; presetting significance thresholds; discarding insignificant association coefficients; treatment of ambiguities in dividing attributes; and the transformation of quantitative measurements to a binary-coded form. A line-printer dendrogram plot displaying the final classification is generated as part of the output. Both normal and inverse association analysis can be performed.