The Effect of Support on Sulphur Tolerance of Rh Based Catalysts for Methane Partial Oxidation

The presence of sulphur containing compounds, naturally occurring in natural gas or added as odorants, can adversely affect the performance of noble metals based catalysts for the partial oxidation of methane to syngas. In this paper the effect of SO₂ addition on the catalytic partial oxidation of methane was investigated on Rh (1 wt.%) catalysts prepared by incipient wetness impregnation method on two different commercially available high temperature γ-alumina supports stabilized either with 10% SiO₂ or 3% La₂O₃. Based on the results of catalytic activity measurements and in-situ FT-IR spectroscopic characterisation, as well as TPR/TPD studies, it has been shown that the presence of sulphur can severely suppress the formation of synthesis gas by inhibiting the reforming reactions during the catalytic partial oxidation of methane. The results also demonstrated that the support plays a crucial role in the partial oxidation reaction. In the presence of a sulphating support such as La₂O₃–Al₂O₃ the partial oxidation reaction was much less inhibited than a less sulphating support such as SiO₂–Al₂O₃. The sulphating support acts as a sulphur storage reservoir, which minimises the poison from adsorbing on or near the active Rh sites where reactions take place.     

Evolutionary neural fuzzy systems for noise cancellation in imagedata

A new class of neural fuzzy filters for removing noise from two-dimensional (2-D) measurement data is presented. The proposed approach combines the advantages of the fuzzy and neural paradigms. The network structure is, in fact, specifically designed to exploit the effectiveness of fuzzy reasoning in removing noise without destroying the useful information embedded in the input data. An easy design of new filters is thus obtained because the neuro-fuzzy approach is capable of automatic acquisition of knowledge for a given network structure. The learning method based on genetic algorithms performs an effective training of the network yielding satisfactory results after a few generations. Experimental results show that the proposed approach is very effective also in the presence of data highly corrupted by noise. The neural fuzzy system is largely able to outperform other methods in the literature including state-of-the-art techniques     

Light aversion in mice depends on nonimage-forming irradiance detection.

Detection of light in the eye underlies image-forming vision, but also regulates adaptive responses in physiology and behavior. Typically these adaptive responses do not involve image-forming vision, but depend on a relatively absolute measure of brightness (nonimage-forming irradiance detection). The goal of this study was to further understand how image-forming vision and nonimage-forming irradiance detection contribute to the effects of light on behavior. Three light dependent behaviors were assessed in wild-type, Rpe65-/- and rd1 mice. In Rpe65-/- mice, nonimage-forming irradiance detection is severely attenuated, but rod based visual acuity is relatively preserved. In rd1 mice visual acuity is nonrecordable, but nonimage-forming responses are less severely attenuated than Rpe65-/-. Positive masking, an image-forming vision dependent increase in wheel running, was absent in rd1 and restricted to higher irradiances in Rpe65-/-. Negative masking, a suppression of wheel running sensitivity with nonimage-forming irradiance detection input, was increased in rd1, but reduced in Rpe65-/- mice. By contrast, light aversion, an avoidance of brightly lit areas, was abolished in both Rpe65-/- and rd1. This shows that image-forming vision is not sufficient for light aversion, suggesting nonimage-forming irradiance detection motivates this behavior. Further, the differing effects of disease suggest that negative masking and light aversion are distinct responses with specialized nonimage-forming irradiance detection pathways. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serious conduct problems in the children of adolescent mothers: Disentangling confounded correlations.

Early motherhood (r?=?.33) with the number of Diagnostic and Statistical Manual of Mental Disorders (DSM-III) symptoms of conduct disorder in a sample of 253 boys (aged 6–13 yrs) who had been referred to outpatient clinics. The following models were compared using path analysis: (1) Teenage motherhood, parental antisocial personality, and socioeconomic status (SES) each contribute uniquely to the prediction of childhood conduct problems; (2) teenage motherhood mediates the association of SES and parental antisocial personality with child conduct problems; and (3) teenage motherhood is spuriously related with child conduct problems because of common associations with SES and parental antisocial personality. Model (3) best fit the data. Similar results were obtained whether maternal age at the birth of the firstborn child or the proband child was used to define maternal age and when teenage motherhood was defined as giving birth at     

Noise removal from image data using recursive neurofuzzy filters

Neurofuzzy approaches are very promising for nonlinear filtering of noisy images. An original network topology is presented in this work to cope with different noise distributions and mixed noise as well. The multiple-output structure is based on recursive processing. It is able to adapt the filtering action to different kinds of corrupting noise. Fuzzy reasoning embedded into the network structure aims at reducing errors when fine details are processed. Genetic learning yields the appropriate set of network parameters from a collection of training data. Experimental results show that the proposed neurofuzzy technique is very effective and performs significantly better than well-known conventional methods in the literature     

An adaptive finite element scheme to solve fluid-structure vibration problems on non-matching grids

This paper deals with the computation of the vibration modes of a system consisting of a linear elastic solid interacting with an acoustic fluid. A finite element method based on meshes for each medium not matching on the fluid-solid interface is analyzed. Optimal order of convergence is proved for the approximation of the eigenfunctions, as well as a double order for the eigenvalues. Numerical tests confirming the theoretical results and showing the advantage of using non-matching grids are reported. Finally, an a posteriori error estimator for this method is introduced and combined with a mesh refinement strategy. The efficiency of this adaptive technique is tested with further numerical experiments. Received: 30 January 2001 / Accepted: 30 May 2001     

Age differences and the identity negative priming effect: An updated meta-analysis.

A recent meta-analysis (P. Verbaeghen & L. De Meersman, 1998a) revealed that older adults show a reliable but significantly reduced negative priming effect compared with young adults. The present study provides an updated quantitative review on the effect of aging on the magnitude of the negative priming effect in identity tasks. This analysis demonstrated that the negative priming effect was not significantly different between young and old adults. This result differs from P. Verhaeghen and L. De Meersman's study. The implications of this finding for inhibitory-based theories of cognitive aging are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reliability enhancement with the aid of transient infrared thermal analysis of smart Power MOSFETs during short circuit operation

The usage of novel measurement techniques enhances the capabilities of researchers and power device manufacturers to understand and address reliability problems in novel Smart Power Devices. Along this line of argument, this work describes a method to improve the reliability of the smart Power MOSFET devices by design. The design optimization process involves Silicon layout, interconnections, packaging and protection strategy as well. Accurate thermal transient analyses, made possible by the unique features of a custom infrared radiometric microscope experimental setup which allows dynamic temperature detection with a bandwidth of 1 MHz over the chip area, indicated the way to minimize peak temperature and to verify the effect of the optimization.