Development and testing of an intermediate temperature glass sealant for use in mixed ionic and electronic conducting membrane reactors

High temperature ceramic membranes have interesting possibilities for application in areas of new and developing technologies such as hydrocarbon combustion with carbon dioxide capture and electrochemical promotion of catalysis (EPOC). However, membrane module sealing remains a significant technical challenge. In this work a borosilicate glass sealant (50SiO₂·25B₂O₃·25Na₂O, mol%) was developed to fit the requirements of sealing an air separation membrane system at intermediate temperatures (300-600 °C). The seal was assessed by testing the leak rates under a range of conditions. The parameters tested included the effect of flowrate on the leak rate, the heating and cooling rates of the reactor and the range of temperatures under which the system could operate. Tests for durability and reliability were also performed. It was found that the most favourable reactor configuration employed a reactor with the ceramic pellet placed underneath the inner chamber alumina tube (inverted configuration), using a quartz wool support to keep the membrane in place prior to sealing. Using this configuration the new glass-based seal was found to be a more suitable sealant than traditional alternatives; it produced lower leak rates at all desirable flowrates, with the potential for rapid heating and cooling and multiple cycling, allowing for prolonged usage. © 2010 Elsevier B.V. All rights reserved.

Remote control of the activity of a Pt catalyst supported on a mixed ionic electronic conducting membrane

A novel configuration for the in situ control of the catalytic activity of a polycrystalline Pt catalyst supported on a mixed ionic electronic conducting (MIEC) substrate is investigated. The modification of the catalytic activity is achieved by inducing the reverse spillover of oxygen promoting species from the support onto the catalyst surface, thus modifying the chemisorptive bond energy of the gas phase adsorbed reactants. This phenomenon is known as Electrochemical Promotion of Catalysis (EPOC). In this work we investigate the use of a wireless system that takes advantage of the mixed ionic electronic conductivity of the catalyst support (internally short-circuiting the system) in a dual chamber reactor. In this wireless configuration, the reaction takes place in one chamber of the membrane reactor while introduction of the promoting species is achieved by the use of an appropriate sweep gas (and therefore control of the oxygen chemical potential difference across the membrane) on the other chamber. Experimental results have shown that the catalytic rate can be enhanced by using an oxygen sweep, while a hydrogen sweep can reverse the changes. Total rate enhancement ratios of up to 3.5 were measured. © 2008 Elsevier B.V. All rights reserved.

Electrochemical promotion of catalysis controlled by chemical potential difference across a mixed ionic-electronic conducting ceramic membrane - An example of wireless NEMCA

A La_0.6Sr_0.4Co_0.2F_0.8O₃ mixed ionic electronic conducting (MIEC) membrane was used in a dual chamber reactor for the promotion of the catalytic activity of a platinum catalyst for ethylene oxidation. By controlling the oxygen chemical potential difference across the membrane, a driving force for oxygen ions to migrate across the membrane and backspillover onto the catalyst surface is established. The reaction is then promoted by the formation of a double layer of oxide anions on the catalyst surface. Thelectronic conductivity of the membrane material eliminates the need for an external circuit to pump the promoting oxide ion species through the membrane and onto the catalyst surface. This renders this "wireless" system simpler and more amenable for large-scale practical application. Preliminary experiments show that the reaction rate of ethylene oxidation can indeed be promoted by almost one order of magnitude upon exposure to an oxygen atmosphere on the sweep side of the membrane reactor, and thus inducing an oxygen chemical potential difference across the membrane, as compared to the rate under an inert sweep gas. Moreover, the rate does not return to its initial unpromoted value upon cessation of the oxygen flow on the sweep side, but remains permanently promoted. A number of comparisons are drawn between the classical electrochemical promotion that utilises an external circuit and the "wireless" system that utilises chemical potential differences. In addition a 'surface oxygen capture' model is proposed to explain the permanent promotion of the catalyst activity. © 2007 Springer Science+Business Media, LLC.

Wireless electrochemical modification of catalytic activity on a mixed protonic-electronic conductor

A novel approach to electrochemical modification of catalytic activity using a wireless configuration has been undertaken. This paper presents preliminary results on the modification of a platinum catalyst film supported on a pellet of Sr_0.97Ce_0.9Yb_0.1O_3-δ (SCYb), considered to be a mixed protonic-electronic conductor under reducing conditions. The wireless configuration utilises the mixed ionic and electronic conductivity of the supporting membrane to supply an ionic promoting species to the catalyst surface. Control of the flux of this species is achieved by adjusting the effective hydrogen chemical potential difference across the membrane in a dual-chamber reactor with one chamber acting as the "reaction side" and the other as the "sweep side". The reaction rate can be promoted by up to a factor of 1.6, for temperatures around 500 °C and low reactant concentrations, when hydrogen is introduced on the sweep side of the membrane reactor. The use of helium, moist helium and oxygen in helium as sweep gases did not modify the reaction rate. © 2007 Elsevier B.V. All rights reserved.

In situ modification of a Pt catalyst supported on a mixed ionic-electronic conducting membrane

The electrochemical promotion of a platinum catalyst for ethylene oxidation on a dual chamber membrane reactor was studied. The catalyst was supported on a La_0.6Sr_0.4Co_0.2Fe_0.803 membrane. Due the supporting membrane's electronic conductivity it is possible to promote the reaction by controlling the oxygen chemical potential difference across the membrane. Upon establishment of an oxygen potential difference across the membrane, oxygen species can migrate and spillover onto the catalyst surface, modifying the catalytic activity. Initial experiments showed an overall promotion of approximately one order of magnitude of the reaction rate of ethylene, under an oxygen atmosphere on the sweep side of the membrane reactor, as compared with the rate under an inert sweep gas. The reaction rate can keep its promoted state even after the flow of oxygen on the sweep side was interrupted. This behavior caused further promotion with every experiment cycle. The causes of permanent promotion and on demonstrating controllable promotion of the catalytic activity are presented. This is an abstract of a paper presented at the AIChE Annual Meeting (San Francisco, CA 11/12-17/2006).

Does childhood bullying lead to the development of psychotic symptoms? A meta-analysis and review of prospective studies

Purpose: Researchers have demonstrated associations between trauma and psychosis. Childhood trauma, in particular, appears to be an important determinant. Recently, bullying has become considered a traumatic experience in its own right. This review aims to analyse research with prospective designs, which will enable conclusions about whether or not bullying causes psychosis.

Methods: A systematic review of the literature was carried out independently by two reviewers. Eligibility and quality assessment criteria were applied. A meta-analysis and narrative synthesis were then completed.

Results: Ten studies met inclusion criteria. Four used data from the same large database, and were combined as one. The majority provided confirmation that bullying appears to cause later development of psychosis. A meta-analysis yielded an unadjusted odds ratio (OR) of 2.148 [95% confidence interval (CI) 1.140–4.044].

Conclusions: The studies reviewed here suggest that bullying does predict the later development of psychotic symptoms. What is lacking from the literature is adequate investigation into other potential mediating factors. The current review highlights the significant role of bullying within this complex interaction. Potential mediating variables are explored, including a dose–response effect for the severity and frequency of victimization. Suggestions for targeting intervention are also suggested alongside clinical implications and recommendations for future research.

Tools and Environments for Networked Electronic Performance

A collection of software and hardware tools and environments that facilitate collective networked performance between electronic musicians. Tools include 'Chat Monkey', a live chat tool for performance, 'DMA Sequencing', a step sequencer using open sound control messaging and multi nodal control, 'tutti, duet, trio, solo, quartet', an ensemble management environment, and 'Por Larrañaga', a cigar box based electro-acoustic instrument with embedded sensors and controllers. Notable performances: w/BLISS, NCAD, Dublin, 1 March 2015; w/BLISS, NI Science Festival, Belfast, 21 Feb 2015

Bullying Experiences of Child and Adolescent Mental Health Service-users: A Pilot Survey

Victims and perpetrators of bullying experience a variety of psychological problems. The aim of the current pilot study was to explore the bullying experiences of Child and Adolescent Mental Health (CAMHS) service-users. The investigation was conducted as a cross-sectional survey at a community-based specialist CAMH service. A modified version of the Revised Olweus Bully/Victim Questionnaire was used to assess bullying experiences. Participants comprised an opportunity sample of 26 adolescent male and female CAMH service-users. Results indicated that 61.5% of participants reported being bullied. Clear links were made between being bullied and the mental health of participants, with 62.5% of bullied participants reporting that being bullied was a ‘‘moderately importantvery important’’ reason for their attendance at the CAMH service. Therapists at the CAMH service made appropriate enquiries about young people being victims of bullying, but more enquiries could be made about young peoples’ experiences as perpetrators. Service-users favoured therapist-led bullying interventions such as assertiveness training, therapy and/or psychological coping strategies, and social skills training. These findings underline the need for ecological approaches to dealing with bullying, and suggest that CAMH services could play an important role in establishing and supporting such interventions.

Real-space grids and the Octopus code as tools for the development of new simulation approaches for electronic systems

Real-space grids are a powerful alternative for the simulation of electronic systems. One of the main advantages of the approach is the flexibility and simplicity of working directly in real space where the different fields are discretized on a grid, combined with competitive numerical performance and great potential for parallelization. These properties constitute a great advantage at the time of implementing and testing new physical models. Based on our experience with the Octopus code, in this article we discuss how the real-space approach has allowed for the recent development of new ideas for the simulation of electronic systems. Among these applications are approaches to calculate response properties, modeling of photoemission, optimal control of quantum systems, simulation of plasmonic systems, and the exact solution of the Schrödinger equation for low-dimensionality systems.