Along-the-channel modeling and analysis of PEFCs at low stoichiometry: Development of a 1+2D model

Water management remains a key challenge in polymer-electrolyte fuel cells. In this work, a pseudo 3-D (1+2D) model is developed to account better for changes of water management along the channel, as well as verify the possibilities of using differential cells for data capture and translation to integral cell performance. An accurate 2-D membrane-electrode-assembly model is developed for differential cell modeling, which is combined with an along-the-channel stepping algorithm to account for down the channel changes in pressure, temperature, reactant concentration, and relative humidity. Variations in cell performance along the channel due to changes in operating conditions are characterized quantitatively and optimized, where drier feed conditions demonstratively require such an approach. Overall, the study identifies gaps between differential and integral cells including those related to flow velocity and highlights the need for better models to understand and link integral cell performance and water management

Apparent ferromagnetism in the 'pinwheel' artificial spin ice

Magnetic artificial spin ice provides examples of how competing interactions between magnetic nanoelements can lead to a range of fascinating and unusual phenomena. We examine theoretically a class of spin ice tilings, called pinwheel, for which near degeneracy of spin configuration energies can be achieved. The pinwheel tiling is a simple but crucial variant on the square ice geometry, in which each nanoelement of square ice is rotated some angle about its midpoint. Surprisingly, this rotation leads to an intriguing phase transition; and even though the spins are not parallel to one another, a ferromagnetic phase is found for rotation angles near 45∘. Here, magnetic domains and domain walls are found when viewed in terms of net magnetisation. Moreover, the ferromagnetic behaviour of the system depends on its anisotropy which we can control by array shape and size

The problem of interpretation in vignette methodology in research with young people

In this paper we explore how interpretation is dealt with by researchers using a vignette methodology. Researchers using vignette methodology often struggle with interpretation: how to interpret the responses when participants shift between discussing the vignettes as themselves, taking the perspective of the character in the vignette and commenting on what ‘ought’ to happen. We argue that by foregrounding a consideration of the method with an explicitly articulated theoretical position of dialogicality, issues inherent in interpretation become a valuable addition to the research rather than an obstacle to be overcome. In the paper we discuss ‘Louise’ a young carer, detailing the various positions she takes in her talk about the vignette of Mary, a fictitious young carer, to illustrate how a perspective based in dialogical theory contributed to the analysis of her various moves through different identity positions

The Journey to R4D: An institutional history of an Australian Initiative on Food Security in Africa

Internal Revie

Demons of the mind: The ‘psy’ sciences and film in the long 1960s

This introduction provides context for a collection of articles that came out of a research symposium held at the Science Museum's Dana Research Centre in 2018 for the ‘Demons of Mind: the Interactions of the ‘Psy’ Sciences and Cinema in the Sixties' project. Across a range of events and research outputs, Demons of the Mind sought to map the multifarious interventions and influences of the ‘psy’ sciences (psychology, psychiatry, and psychoanalysis) on film culture in the long 1960s. The articles that follow discuss, in order: critical engagement with theories of child development in 1960s British science fiction; the ‘horrors’ of contemporary psychiatry and neuroscience portrayed in the Hollywood blockbuster The Exorcist (1973); British social realist filmmakers' alliances with proponents of ‘anti-psychiatry’; experimental filmmaker Jane Arden's coalescence of radical psychiatry and radical feminist techniques in her ‘psychodrama’ The Other Side of the Underneath (1973); and the deployment of film technologies by ‘psy’ professionals during the post-war period to capture and interpret mother-infant interaction

AFLP/SSR mapping of resistance genes to Alectra vogelii in cowpea (Vigna unguiculata l. Walp)

The parasite weed Alectra vogelii (Benth) causes significant yield reduction of cowpea in Africa. To find and map the resistance gene to A. vogelii in cowpea, a F2 population from a cross involving a resistant parent IT81D-994 and a susceptible TVX3236 was screened. Amplified fragment length polymorphism (AFLP) in combination with Single Sequence Repeat (SSR) analysis was used to identify markers that may be linked to the gene Rav3 conferring resistance to A. vogelii in the cowpea cultivar IT81D-994. The analysis of F2 individuals scored for resistance showedthat a single dominant gene conditioned A. vogelii resistance in IT81D-994 with a probability of 30 to 50%. Sixty-six AFLP/SSR markers were identified. Using MAPMAKER, four linkage groups were found. The first group showed 33 markers linked to the susceptible gene. The closest identified marker was 21.4 centimorgans away from the susceptible gene. The primer combination that showed the closest linkage was 809ACG8 (E-ACG 8 + UBC-809). The second group indicated 4 markers linked together while the third and the fourth groups showed 2 markers linkedtogether respectively. No markers were found linked to the resistance gene Rav3 conferring the resistance in the cultivated cowpea cultivar IT81D-994.La plante parasite Alectra vogelii (Benth) provoque une réduction significative du rendement de niébé en Afrique. Pour repérer et cartographier le gène de résistance à A. vogelii, une population F2 issue d’un croisement impliquant le cultivar résistant IT81D-994 et le cultivar sensible TVX3236 a été criblée. La technique Amplified fragment length polymorphism (AFLP) en combinaison avec des Séquences Simples Répétés (SSR) a été utilisée pour identifier les marqueurs qui seraient liés au gène Rav3 qui confère la résistance à A. vogelii chez le cultivar de niébé IT81D- 994. L’analyse des individus F2 montrant une résistance indique qu’un seul gène dominant conditionne la résistance à A. vogelii chez IT81D-994 avec une probabilité de 30 à 50 %. Soixante six marqueurs AFLP/SSR ont été identifiés. A l’aide de MAPMAKER, 4 groupes de liaison ont été trouvés. Le premier groupe montre 33 marqueurs liés au gène sensible. Le marqueur le plus proche identifié est à 21.4 centimorgans du gène sensible. La combinaison d’amorces ayant des liaisons les plus proches était 809ACG8 (E-ACG 8 + UBC-809). Le secondgroupe montre 4 marqueurs liés ensemble tandis que le troisième et le quatrième groupe montrent 2 marqueurs liés entre eux respectivement. Aucun marqueur n’a été trouvé lié au gène Rav3 qui confère la résistance au cultivar de niébé cultivé IT81D-994.Key words: Parasite, weeds, legumes, molecular marker

On the cyclically fully commutative elements of Coxeter groups

Let W be an arbitrary Coxeter group. If two elements have expressions that are cyclic shifts of each other (as words), then they are conjugate (as group elements) in W. We say that w is cyclically fully commutative (CFC) if every cyclic shift of any reduced expression for w is fully commutative (i.e., avoids long braid relations). These generalize Coxeter elements in that their reduced expressions can be described combinatorially by acyclic directed graphs, and cyclically shifting corresponds to source-to-sink conversions. In this paper, we explore the combinatorics of the CFC elements and enumerate them in all Coxeter groups. Additionally, we characterize precisely which CFC elements have the property that powers of them remain fully commutative, via the presence of a simple combinatorial feature called a band. This allows us to give necessary and sufficient conditions for a CFC element w to be logarithmic, that is, ℓ(wk)=k⋅ℓ(w) for all k≥1, for a large class of Coxeter groups that includes all affine Weyl groups and simply laced Coxeter groups. Finally, we give a simple non-CFC element that fails to be logarithmic under these conditions

Disinfection of Swine Wastewater Using Chlorine, Ultraviolet Light and Ozone

Veterinary antibiotics are widely used at concentrated animal feeding operations (CAFOs) to prevent disease and promote growth of livestock. However, the majority of antibiotics are excreted from animals in urine, feces, and manure. Consequently, the lagoons used to store these wastes can act as reservoirs of antibiotics and antibiotic-resistant bacteria. There is currently no regulation or control of these systems to prevent the spread of these bacteria and their genes for antibiotic resistance into other environments. This study was conducted to determine the disinfection potential of chlorine, ultraviolet light and ozone against swine lagoon bacteria. Results indicate that a chlorine dose of 30 mg/L could achieve a 2.2-3.4 log bacteria reduction in lagoon samples. However, increasing the dose of chlorine did not significantly enhance the disinfection activity due to the presence of chlorine-resistant bacteria. The chlorine resistant bacteria were identified to be closely related to Bacillus subtilis and Bacillus licheniformis. A significant percentage of lagoon bacteria were not susceptible to the four selected antibiotics: chlortetracycline, lincomycin, sulfamethazine and tetracycline (TET). However, the presence of both chlorine and TET could inactivate all bacteria in one lagoon sample. The disinfection potential of UV irradiation and ozone was also examined. Ultraviolet light was an effective bacterial disinfectant, but was unlikely to be economically viable due to its high energy requirements. At an ozone dose of 100 mg/L, the bacteria inactivation efficiency could reach 3.3−3.9 log

Preliminary Survey of Chemical Contaminants in Water, Sediment, and Aquatic Biota at Selected Sites in Northeastern Florida Bay and Canal C-111

Several actions are under way to alter water management capabilities and practices in south Florida in order to restore a more natural hydroperiod for the Everglades. Because relatively little research has been conducted on contaminants entering Florida Bay, we undertook a preliminary study in June 1995 to determine contaminant concentrations in surface water, sediment, and biota prior to major changes in water management. The areas studied were the C-111 canal (five sites) beginning just above water control structure S-197 and extending to Manatee Bay (part of the Biscayne Bay system), Shell Creek (three sites), the mouth of Taylor River, Trout Creek (two sites), and a site near the Key Largo Ranger Station. Hydrographic observations were made at each site, and samples of water and sediment were collected at each of the five areas except the Key Largo site. Bioresidues were determined for indigenous oysters collected from the C-111 canal and Shell Creek and for transplanted oysters exposed at the Key Largo site, the C-111 canal, Shell Creek, Taylor River, and Trout Creek for 5-29 days. Water samples were analyzed for selected organochlorine pesticides and metals; sediments were analyzed for the same compounds and for polycyclic aromatic hydrocarbons (PAHs). Fish filets and shucked oysters were analyzed for selected organochlorine pesticides, polychlorinated biphenyl (PCB) congeners, and metals. Other than low dissolved oxygen at some C-111 canal sites, water quality was generally good. Most contaminants were below water and sediment quality guidelines designed to protect aquatic life, and contaminant concentrations in oysters were low. Threshold effect levels were exceeded for some organochlorine pesticides and PAHs in some sediment samples, but all values measured were below probable effect levels. Low concentrations of organochlorine pesticides were detected in sediments from the C-111 canal, Shell Creek, Taylor River, and Trout Creek; except for Taylor River, low concentrations of PCB congeners and PAHs were detected from the same areas. The only organochlorine pesticide detected in filets from seven fish was 3.2 v-g DDE/kg (wet weight) in a sea catfish. Total mercury concentrations in filets of four species of fishes ranged from 0.53 to 1.3 μg/g, wet weight, which falls within a limited consumption advisory by the State of Florida