Epitaxial Methylammonium Lead Iodide Perovskites for Inexpensive and Efficient Solar Harvesting

Our planet’s ever-increasing energy consumption drives a search for inexpensive and efficient renewable energy sources, and the sun could be the answer. Emerging inorganic-organic solar cell technology utilizing methylammonium metal halides with the perovskite structure experienced five-fold increase in power conversion efficiency since its introduction, from 3.8 % in 2009 to 20.1 % in 2014. These solar cells show potential to greatly cut costs of solar energy harvesting: however epitaxial films remain unexplored. I will present a novel method to electrochemically synthesize epitaxial CH3NH3PbI3 films with the perovskite structure. Epitaxial PbO2 is converted to epitaxial CH3NH3PbI3 perovskite of tunable morphology and crystal orientation by simple dip conversion. Solar cells constructed with epitaxial CH3NH3PbI3 should exhibit increased efficiencies because the density of bulk and interface defects is minimized. This method could be integrated into cells to provide a clean and more cost-effective alternative to traditional silicon single crystal technology

Effects of the Ergopeptines Associated With Tall Fescue on Post Exercise Recovery of Horses Subjected to an Anaerobic Standard Exercise Test

The objective of this study was to examine the effects of tall fescue seed infected with both ergovaline and ergotamine on post exercise recovery of horses subjected to an anaerobic standard exercise test (SET) under hot, humid conditions. Ten quarter horses were selected then paired by body weight (BW), age, and skill level and randomly assigned to either group A or group B that were fed a diet which contained either (E+) or was free of (E-) ergot alkaloids for a 35 d period (P1). Then groups were switched to the opposite diet for the second 35 d period (P2). The E+ diet contained 8.2% seed resulting in 132 ppb ergovaline and 275 ppb ergotamine. Horses were ridden 5 d per week. During wks 3 and 5 (P1) and wks 8 and 10 (P2), horses were subjected to a standard exercise test (SET) designed to obtain a maximal heart rate (HR) (& 150 bpm). During the SET, HR exceeded 150 bpm after the first set of 10 turns and values for lactate (LA) 1 min post SET averaged 10.18 mmol/L, thus confirming horses performed above the anaerobic threshold. A difference among horses was observed for LA, HR, respiratory rate (RR), and rectal temperature (RT) (P & 0.05). Treatment had no effect on RT or LA at any time measured. Heart rates at the end and 1 min post SET were unaffected by seed treatment. When horses consumed E+ diets, HR were lower at rest, during the SET, and at both 5 and 10 min of recovery (P & 0.05). Respiration rates did not vary by treatment at rest or 1, 5, and 10 min post SET, but was higher for the E+ treatment at 30 and 60 min post SET (P ≤ 0.006). Consumption of ground fescue seed caused horses to expend more respiratory effort due to peripheral vasoconstriction as was indicated by lower HR\u27s

<i>In situ</i> XANES Study of Co²⁺ Ion Adsorption on Fe₃O₄ Nanoparticles in Supercritical Aqueous Fluids

ABSTRACTIn situ x-ray absorption spectroscopy (XAS) measurements were made on Fe3O4 nanoparticles in supercritical aqueous fluids to 500 °C in order to study their reactivity with Co2+ aqua ions and to investigate the structural properties of the reacted nanoparticles. The analyses of the x-ray absorption near edge structure (XANES) of XAS indicate that reactivity of Fe3O4 nanoparticles with Co2+ ions is minimal to 200 °C but becomes significant in the 250–500 °C temperature range. XANES and angular momentum projected density of states (l-DOS) calculations were carried out using the FEFF8.2 code and analyses were made using multi-peak fitting to determine the origin of the features exhibited in the spectra.</jats:p

Non-adherence to COVID-19 guidelines on handwashing and social distancing on the island of Ireland

Abstract Background COVID-19 public health measures like handwashing and social distancing can help stem the spread of the virus. Adherence to guidelines varies between individuals. This study aims to identify predictors of non-adherence to social distancing and handwashing guidelines. Methods A cross-sectional weekly telephone survey was conducted over eight weeks (11/06/2020-05/08/2020). The sample included adults resident on the island of Ireland (75:25 split between ROI and NI). Data were collected on demographics, threat perceptions, fear of COVID-19, response efficacy and self-efficacy, response cost and social norms, COVID-19 behaviours, mood, loneliness, and self-reported health. Results 3011 participants were surveyed. Handwashing non-adherers were more likely to be male (OR: 5.2, 95% CI: 2.4 - 11.3), to have higher levels of loneliness (OR: 1.86, 95% CI: 1.1 - 3.1), and higher perceptions of handwashing costs (OR: 3.4, 95% CI: 2.2 - 5.2). Those reporting rarely engaging in social distancing were more likely to be members of lower socioeconomic groups, to be younger (OR: 0.97, 95% CI: 0.96 - 0.98), male (OR: 1.67, 95% CI: 1.1 - 2.5), healthcare workers (OR: 1.98, 95% CI: 1.1 - 3.4), to report lower mood (OR: 1.72, 95% CI: 1.3 - 2.2), were less likely to live in households with people aged under-18 (OR: 0.75, 95% CI: 0.6 - 0.9), and to have lower fear of COVID-19 (OR: 0.79, 95% CI: 0.6 - 0.9). Conclusions Non-adherers to handwashing differ from social distancing non-adherers. Public health messages should target specific demographic groups and different messages are necessary to improve adherence to each behaviour. </jats:sec

Epitaxial Electrodeposition of Methylammonium Lead Iodide Perovskites

An electrochemical/chemical route is introduced to deposit both textured and epitaxial films of methylammonium lead iodide (MAPbI₃) perovskites. The perovskite films are produced by chemical conversion of lead dioxide films that have been electrodeposited as either textured or epitaxial films onto [111]-textured Au and [100] and [111] single-crystal Au substrates. The epitaxial relationships for the MAPbI₃ films are MAPbI₃(001)­[010]∥PbO₂(100)⟨001⟩ and MAPbI₃(110)­[111]∥PbO₂(100)⟨001⟩ regardless of the Au substrate orientation, because the in-plane order of the converted film is controlled by the epitaxial PbO₂ precursor film. The textured and epitaxial MAPbI₃ films both have trap densities lower than and photoluminescence intensities higher than those of polycrystalline films produced by spin coating