Kinetics of radical polymerization,LIII. The absolute rate constants in the radical polymerization of ethyl acrylate

The dependence of dilution on the chain propagation and termination rate constants was investigated in the polymerization of ethyl acrylate in benzene solution at 50°C, with the rotating sector method. The errors of the above rate constants were determined and, by our method applied to decrease these errors, the errors of the propagation rate constant was reduced to its half value. By the application of our earlier results in polymerization kinetics, we found that in this system the chain propagation step is exclusively responsible for the solvent effects observed. Our experimental results can be quantitatively described in terms of the hot redical theory.     

Applications of microsatellite-based Y chromosome haplotyping

Y-chromosomal microsatellites have been investigated for the purposes of application to male identification, population genetics and population history. With nine markers, every male in a German population sample (n = 70) could be identified by an individual-specific Y microsatellite haplotype. The analysis of 474 unrelated males of nine human populations with seven markers revealed 301 different Y haplotypes. The analysis of molecular variance (AMOVA) approach was used to detect male population characteristics of Y microsatellite haplotypes. With pairwise comparisons of inter-population variance, most of the populations could be distinguished significantly. Sixty individuals from different male populations in Asia and Northern Europe carrying a novel Y-chromosomal T-->C transition show reduced microsatellite variability together with haplotype similarities. Microsatellite data suggest that the mutation occurred recently in Asia, supporting the hypothesis of Asian ancestry of some northern European populations.     

A psychometric study of the McMaster Family Assessment Device in psychiatric, medical, and nonclinical samples.

Investigated the psychometric properties of the McMaster Family Assessment Device (FAD [N. Epstein et al; see PA, Vol 71:2891]), a multidimensional measure of family functioning, using data from psychiatric (n?=?1,138), nonclinical (n?=?627), and medical (n?=?298) samples. Internal scale reliabilities and factorial validity were assessed for each group, and results were compared across groups. In general, scale reliabilities were favorable and the hypothesized factor structure of the FAD was supported. Results also support the use of the 60-item version over the original 53-item version. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physicochemical and toxicological properties of commercial carbon blacks modified by reaction with ozone

Ozonation of two commercial carbon blacks (CBs), Printex 90 (P90) and Flammruss 101 (F101), was carried out and changes in their morphology, physical properties, and cytotoxicity were examined. The hypothesis examined was that different methods of manufacture of CBs influence their chemical reactivity and toxicological properties. Structural changes were examined by X-ray photoelectron spectroscopy, infrared spectroscopy, Raman spectroscopy, and electron paramagnetic resonance spectroscopy (EPR). Introduction of surface oxygen functionality upon ozonation led to changes in surface charge, aggregation characteristics, and free radical content of the CBs. However, these changes in surface functionality did not alter the cytotoxicity and release of inflammation markers upon exposure of the CBs to murine macrophages. Interaction of macrophages with F101 resulted in higher levels of inflammatory markers than P90, and the only structural correlation was with the higher persistent radical concentration on the F101.     

Assessment of nuclear energy sustainability index using fuzzy logic

Nuclear energy is increasingly perceived as an attractive mature energy generation technology that can deliver an answer to the worldwide increasing energy demand while respecting environmental concerns as well as contributing to a reduced dependence on fossil fuel. Advancing nuclear energy deployment demands an assessment of nuclear energy with respect to all sustainability dimensions.In this paper, the nuclear energy, whose sustainability will be assessed, is governed by the dynamics of three subsystems: environmental, economic, and sociopolitical. The overall sustainability is then a non-linear function of the individual sustainabilities. Each subsystem is evaluated by means of many components (pressure, status, and response). The combination of each group of indicators by means of fuzzy logic provides a measurement of sustainability for each subsystem.     

New breeding gain definitions and their application to the optimization of a molten salt reactor design

The molten salt reactor (MSR) is an attractive breeder reactor. A graphite-moderated MSR can reach breeding because of the online salt processing and refueling. These features give difficulties when the breeding gain (BG) of the MSR is evaluated. The inventory of the core and external stockpiles have to be treated separately in order to quantify the breeding performance of the reactor. In this paper, an improved BG definition is given and it is compared with definitions used earlier. The improved definition was used in an optimization study of the graphite – salt lattice of the core. The aim of the optimization is a passively safe, self-breeder reactor. The fuel channel diameter, graphite volume and thorium concentration were varied while the temperature feedback coefficient of the core, BG – as defined in the paper – and the lifetime of the graphite were calculated. There is a small range of lattices which provide both negative temperature feedback and breeding. Furthermore, breeding is possible only at low power densities in case of the salt processing efficiencies set in this study. In this range of power the lifetime of the graphite is between 12 and 20 years.     

Über den Pyridingehalt des Tabaks

European Food Research and Technology - In unseren Versuchstabaken (Ungarische Tabake und Trafikfabrikaten) konnten wir Pyridin bzw. Pyridinbasen überhaupt nicht oder nur in Spuren...     

Asymmetries in simple feature searches for color

Observers were required to search for and find a target stimulus that differed from distractor stimuli only in chromaticity. Pairs of target and distractor colors were chosen so that in some conditions the two members of a pair differed in hue, in saturation, or in both hue and saturation. For each type of condition, a number of pairs of colors representing varying degrees of perceptual difference were chosen. Each member of each pair of colors served as both the target and distractor color while the other member of the pair served in the remaining role. The largest asymmetries in search times occurred when the target and distractors differed in saturation. Somewhat smaller asymmetries occurred with differences in both saturation and hue, and no asymmetries occurred with hue differences. Results suggest that the asymmetries are related to the time required to encode and transmit the chromatic information centrally rather than the properties of the search process itself.     

Switched-Capacitor Track-and-Hold Amplifiers With Low Sensitivity to Op-Amp Imperfections

This paper describes high-precision switched-capacitor (SC) track-and-hold amplifier (THA) stages. They use a novel continuous-time correlated double sampling (CDS) scheme to desensitize the operation to amplifier imperfections. Unlike earlier predictive-CDS amplifiers, the circuits do not need a sampled-and-held input signal for their operation. During the tracking period, an auxiliary continuous-time signal path is established, which predicts the output voltage during the holding period. This allows accurate operation even for low amplifier gains and large offsets over a wide input frequency range. Extensive simulations were performed to compare the performance of the proposed THAs with earlier circuits utilizing CDS. The results verify that their operation is far more robust than that of any previously described SC amplifiers