Poincare Semigroup Symmetry as an Emergent Property of Unstable Systems

The notion that elementary systems correspond to irreducible representations of the Poincare group is the starting point for this paper, which then goes on to discuss how a semigroup for the time evolution of unstable states and resonances could emerge from the underlying Poincare symmetry. Important tools in this analysis are the Clebsch-Gordan coefficients for the Poincare group.Comment: 17 pages, 1 figur

Ethnic variations in duration of untreated psychosis: report from the CRIS-FEP study

Objectives:  There is inconsistent evidence on the influence of ethnicity on duration of untreated psychosis (DUP). We investigated ethnic differences in DUP in a large epidemiological dataset of first episode psychosis patients in an inner city area of south London, UK. Methods:  We analysed data on 558 first episode psychosis patients at the South London and Maudsley NHS Trust, between 2010 and 2012. We performed multivariable logistic regression to estimate the odds of a short DUP (≤ 6 months) by ethnic group, controlling for confounders. Results:  There was no evidence that ethnicity is associated with duration of untreated psychosis. However, we found evidence that a short DUP was strongly associated with age, living circumstances, and pathways to care variables (involuntary admission, out of office hour contact, accident and emergency referral, criminal justice agency referral and family involvement in help-seeking). Conversely, a long DUP was associated with report of social isolation, living alone, being single and General Practitioner referral. Conclusion:  Our findings suggest that indicators of social isolation were associated with long DUP. Our data also show that pathways into care characteristics play significant role in DUP. Thus, the challenge of tackling the issue of timely access to EI under the new Access and Waiting Time standard for psychosis requires a multilevel approach, including joint working with communities, public awareness of psychosis, less restrictive referral pathways and adequate resourcing of early intervention for psychosis services. These will go a long way in addressing patients’ needs rather than be determined by service structures

Solar Thermal Decoupled Electrolysis: Reaction Mechanism of Cobalt Oxidation

The oxidation of Co(OH)2 at the anode of the H2 producing electrolytic cell was investigated via cyclic voltammetry (CV) and chronocoulometry to develop an explicit description of the reaction mechanism. It was found that the behavior at the anode is very complex; by varying the switching potentials and number of cycles in the CV, the shapes of the voltammograms change. Chronocoulometry studies provide evidence of surface adsorption. From the CV studies, it was also determined that Co(OH)2 is oxidized to CoOOH at a potential close to the thermodynamically predicted value of -0.112 V vs Ag/AgCl (3M NaCl) at 298 K. Thus, it is believed both absorption and diffusion reactions occur simultaneously

Solar thermal decoupled water electrolysis process I: Proof of concept

A new concept for a solar thermal electrolytic process was developed for the production of H-2 from water. A metal oxide is reduced to a lower oxidation state in air with concentrated solar energy. The reduced oxide is then used either as an anode or solute for the electrolytic production of H-2 in either an aqueous acid or base solution. The presence of the reduced metal oxide as part of the electrolytic cell decreases the potential required for water electrolysis below the ideal 1.23 V required when H-2 and O-2 evolve at 1 bar and 298 K. During electrolysis, H-2 evolves at the cathode at 1 bar while the reduced metal oxide is returned to its original oxidation state, thus completing the H-2 production cycle. Ideal sunlight-to-hydrogen thermal efficiencies were established for three oxide systems: Fe2O3-Fe3O4, Co3O4-CoO, and Mn2O3-Mn3O4. The ideal efficiencies that include radiation heat loss are as high or higher than corresponding ideal values reported in the solar thermal chemistry literature. An exploratory experimental study for the iron oxide system confirmed that the electrolytic and thermal reduction steps occur in a laboratory scale environment

The Thermal Electrolytic Production of Mg from MgO: A Discussion of the Electrochemical Reaction Kinetics and Requisite Mass Transport Processes

We examined the kinetic and transport processes involved in Mg production from MgO via electrolysis at ca 1250 K with in a eutectic mixture of MgF2–CaF2, using a Mo cathode, and carbon anode. Exchange current densities, transfer coefficients, and diffusion coefficients of the electroactive species were established using a combination of cyclic and linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The cathode kinetics are described by a concentration dependent Butler–Volmer equation. The exchange current density and cathodic transfer coefficient are 11±4 A cm−2 and 0.5±0.12 respectively. The kinetics of the anode are described by two Tafel equations: at an overvoltage below 0.4 V, the exchange current density is 0.81±0.2 mA cm−2 with an anodic transfer coefficient of 0.5±0.1; above 0.4 V overvoltage the values are 0.14±0.05 mA cm−2 and 0.7±0.2 respectively. The diffusion coefficients of the electroactive species are D(Mg2+)=5.2±0.6E−5 cm2 s−1 and D ()=7.2±0.2E−6 cm2 s−1. The ionic conductivity of the electrolyte is ca 2.6 S cm−1. A 3D finite element model of a simple cell geometry incorporating these kinetic and transport parameters suggest that up to 27% of the energy required to drive the electrolysis reaction can be supplied thermally for a current density of 0.5 A cm−2, enabling a reduction in operating cost if the thermal energy is substituted for valuable electric work