Hydrogen production with nickel powder cathode catalysts in microbial electrolysis cells

Although platinum is commonly used as catalyst on the cathode in microbial electrolysis cells (MEC), non-precious metal alternatives are needed to reduce costs. Cathodes were constructed using a nickel powder (0.5–1 μm) and their performance was compared to conventional electrodes containing Pt (0.002 μm) in MECs and electrochemical tests. The MEC performance in terms of coulombic efficiency, cathodic, hydrogen and energy recoveries were similar using Ni or Pt cathodes, although the maximum hydrogen production rate (Q) was slightly lower for Ni (Q = 1.2–1.3 m³ H₂/m³/d; 0.6 V applied) than Pt (1.6 m³ H₂/m³/d). Nickel dissolution was minimized by replacing medium in the reactor under anoxic conditions. The stability of the Ni particles was confirmed by examining the cathodes after 12 MEC cycles using scanning electron microscopy and linear sweep voltammetry. Analysis of the anodic communities in these reactors revealed dominant populations of Geobacter sulfurreduces and Pelobacter propionicus. These results demonstrate that nickel powder can be used as a viable alternative to Pt in MECs, allowing large scale production of cathodes with similar performance to systems that use precious metal catalysts.     

Design of a Compact Ceramic High-Temperature Heat Exchanger and Chemical Decomposer for Hydrogen Production

This article describes a compact silicon carbide ceramic, high-temperature heat exchanger for hydrogen production in the sulfur iodine thermochemical cycle, and in particular, to be used as the sulfuric acid decomposer. In this cycle, hot helium from a nuclear reactor is used to heat the SI (sulfuric acid) feed components (H₂O, H₂SO₄, SO₃) to obtain appropriate conditions for the SI decomposition reaction. The inner walls of the SI decomposer channels are coated with platinum to catalytically decompose sulfur trioxide into sulfur dioxide and oxygen. Hydrodynamic, thermal, and the sulfur trioxide decomposition reaction were coupled for numerical modeling. Thermal results of this analysis are exported to perform a probabilistic mechanical failure analysis. This article presents the approach used in modeling the chemical decomposition of sulfur trioxide. Stress analysis of the design is also presented. The second part of the article shows the results of parametric study of the baseline design (linear channels). Several alternate designs of the chemical decomposer channels are also explored. The current study summarizes the results of the parametric calculations whose objective is to maximize the sulfur trioxide decomposition by using various channel geometries within the decomposer. Based on these results, a discussion of the possibilities for improving the productivity of the design is also given.     

Imagery assessment through self-report: What do imagery questionnaires measure?

Assessment difficulties have impeded progress in evaluating the therapeutic role of visual imagery. Four studies with 445 undergraduates examined imagery questionnaires and addressed the issues of (a) reliability, (b) agreement among different questionnaires, (c) social desirability, and (d) construct validity. The (Betts) Questionnaire Upon Mental Imagery, Gordon Test of Visual Imagery Control, and a newer inventory, the Paivio Individual Differences Questionnaire, were examined. Reliability of the Paivio inventory was found to be satisfactory and equivalent to that of other imagery questionnaires. In 2 studies, the Betts and Paivio questionnaires were correlated at the .45–.50 level, but correlations involving the Gordon scale were inconsistent from one study to the next. In general, imagery measures were not influenced by social desirability (Marlowe-Crowne Social Desirability Scale). Factor analysis indicated that subjective and objective measures of visualization are independent. The final study revealed a relationship between imagery questionnaire scores and reported values and interests. It is suggested that imagery is not a unitary construct and that criteria other than visuospatial tests may be appropriate for validating imagery questionnaires. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Failure to control postprostatectomy urinary incontinence by urethral compression

A modification of Kaufman's urinary incontinence device was implanted unsuccessfully in 5 patients. This device achieved passive urinary continence in each of these patients; however, all patients continued to experience moderate to severe stress incontinence. The results of this study challenge the concept that static urethral compression can achieve total urinary continence in patients with postprostatectomy incontinence.     

Allocation of attention in dichotic listening: Differential effects on the detection and localization of signals.

In 2 dichotic listening experiments, 96 normal right-handed adults attended selectively to the left and right ear and divided their attention equally between both ears. Participants listened for specified targets and reported the ear of entry. The material consisted of pairs of consonant–vowel syllables in Experiment 1 and pairs of rhyming consonant–vowel–consonant words in Experiment 2. Both experiments yielded a right-ear advantage for detection and for localization. Attention instructions had no effect on detection. However, focusing attention on 1 ear increased the number of targets attributed to that ear while decreasing the number of targets attributed to the opposite ear. The dissociation between detection and localization indicates that volitional shifts of attention influence late (response selection) processes rather than early (stimulus identification) processes. Selective-listening effects can be accounted for by a 2-stage model in which a fixed input asymmetry is modulated by a biased selection of responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effectiveness of cognitive therapy for depression in a community mental health center: A benchmarking study.

The current study examined the feasibility and effectiveness of transporting an empirically supported treatment for depression, cognitive therapy (CT), to a community mental health center setting. CT was delivered to 192 adult outpatients with major depression, and a benchmarking strategy compared results with those of 2 randomized controlled trials (RCTs). The 3 samples were largely similar in terms of initial severity of depression, and CT was as effective in reducing depressive symptoms in the current sample as in the RCTs. More favorable outcome was associated with less severe initial depression, more therapy sessions, more years of education, and absence of a comorbid personality disorder. This study demonstrates that an empirically supported treatment can be transported effectively to a clinical setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aiding Transfer in Statistics: Examining the Use of Conceptually Oriented Equations and Elaborations During Subgoal Learning.

Consistent with a subgoal-learning approach, the authors hypothesized that learners who studied statistics examples with conceptually oriented equations would transfer more successfully to novel problems compared with learners who studied examples using computationally oriented equations. The conceptually oriented equations were designed to capture the relationship between the concept and its computation, whereas the computationally oriented equations were designed to simplify calculations. This hypothesis was supported across 2 experiments. The authors also examined the implications of providing learners with elaborations of the procedures illustrated in the examples either before or after they studied them. The location of the elaborations had no apparent effect. Overall, these results demonstrate that solution procedures organized around appropriate conceptually oriented subgoals are easier to adapt for novel problems than procedures built around computationally friendly, but conceptually opaque, steps. (PsycINFO Database Record (c) 2010 APA, all rights reserved)