50 research outputs found
Efficient Electrocatalytic CO2 Reduction Driven by Ionic Liquid BufferâLike Solutions
We show here that electrocatalysis of CO2 reduction in aqueous electrolytes containing the ionic liquid (IL) 1-n-butyl-2,3dimethylimidazolium acetate ([BMMIm][OAc]) and dimethyl sulfoxide (DMSO) proceeds at low overpotentials (â0.9 V vs. Ag/AgCl) at commercially-available Au electrodes, and with high selectivity for CO production (58% faradaic efficiency at â1.6 V vs Ag/AgCl). 0.43 mol of CO2 per mol of IL can be absorbed into the electrolyte at atmospheric pressure, forming bicarbonate and providing a constant supply of dissolved CO2 to the surface of the electrode. We also show that electrocatalysis of CO2 reduction in the electrolyte is facilitated by stabilization of CO2 radical anions by the imidazolium cations of the IL and buffer-like effects with bicarbonate
Strategies Outside the Formal Classroom: Nonprofit Management Education in Transparency and Accountability
A demand for nonprofit management training and organizational capacity building exists in Latin America. However, few nonprofit management education (NME) programs in Latin America exist, and there is limited content related to ethics, transparency, and accountability. Using the case of Ecuador, we identify three strategies implemented by nonprofit leaders to cope with limited NME. We find that first, organizations engage in a process of collectivity that seeks to explore and give meaning to civil society in Ecuador. Second, this process leads to the production of knowledge about civil society in Ecuador. And third, based on both the process of collectivity and knowledge production, nonprofit leaders in Ecuador take ownership in the training of nonprofit leaders through several pilot courses related to transparency and accountability. The case of Ecuador reminds public affairs educators that organizations themselves can be successful producers of knowledge that can and should create and inform curricular content
Ring electrode for radio-frequency heating of the cornea: modelling and in vitro experiments
[EN] Radio-frequency thermokeratoplasty (RF-TKP) is a technique used to reshape the cornea curvature by means of thermal lesions using radio-frequency currents. This curvature change allows refractive disorders such as hyperopia to be corrected. A new electrode with ring geometry is proposed for RF-TKP. It was designed to create a single thermal lesion with a full-circle shape. Finite element models were developed, and the temperature distributions in the cornea were analysed for different ring electrode characteristics. The computer results indicated that the maximum temperature in the cornea was located in the vicinity of the ring electrode outer perimeter, and that the lesions had a semi-torus shape. The results also indicated that the electrode thickness, electrode radius and electrode thermal conductivity had a significant influence on the temperature distributions. In addition, in vitro experiments were performed on rabbit eyes. At 5 IN power the lesions were fully circular. Some lesions showed non-uniform characteristics along their circular path. Lesion depth depended on heating duration (60% of corneal thickness for 20s, and 30% for 10s). The results suggest that the critical shrinkage temperature (55-63degreesC) was reached at the central stroma and along the entire circular path in all the cases.Berjano, E.; Saiz RodrĂguez, FJ.; AliĂł, J.; Ferrero, JM. (2003). Ring electrode for radio-frequency heating of the cornea: modelling and in vitro experiments. Medical & Biological Engineering & Computing. 41(6):630-639. https://doi.org/10.1007/BF02349970S630639416AliĂł, J. L., Ismail, M. M., Artola, A., andPĂ©rez-Santonja, J. J. (1997a): âCorrection of hyperopia induced by photorefractive keratectomy using non-contact Ho: YAG laser thermal keratoplastyâ,J. Refract. Surg.,13, pp. 13â16AliĂł, J. L., Ismail, M. M., andSanchez, J. L. (1997b): âCorrection of hyperopia with non-contact Ho: YAG laser thermal keratoplastyâ,J. Refract. Surg.,13, pp. 17â22AliĂł, J. 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Psychological and social effects of orthodontic treatment
Adolescents with commonly occurring forms of malocclusion often are presumed to be at risk for negative self-esteem and social maladjustment. A randomized control group design was used to assess the psychosocial effects of orthodontic treatment for esthetic impairment. Ninety-three participants, 11 to 14 years old, with mild to moderate malocclusions, were randomly assigned to receive orthodontic treatment immediately or after serving as delayed controls. A battery of psychological and social measures was administered before treatment, during treatment, and three times after completion of treatment, the last occurring one year after termination. Repeated measures analyses of variance assessed group differences at the five time points. Parent-, peer-, and self-evaluations of dental-facial attractiveness significantly improved after treatment, but treatment did not affect parent- and self-reported social competency or social goals, nor subjects' self-esteem. In summary, dental-specific evaluations appear to be influenced by treatment, while more general psychosocial responses are not.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44814/1/10865_2005_Article_BF01856884.pd
Evaluation of the behavior of Carbon Short Fiber Reinforced Concrete (CSFRC) based on a multi-sensory experimental investigation and a numerical multiscale approach
Carbon fiber reinforcement used in concrete has become a remarkable alternative to steel fibers. Admixing short fibers to fresh concrete and processing the material with a 3D printer leads to an orientation of fibers and a material with high uniaxial strength properties, which offers an economic use of fibers. To investigate its mechanical behavior, the material is subjected to flexural and tensional tests, combining several measuring techniques. Numerical analysis complements this research. Computed tomography is used with several post-processing algorithms for separating matrix and fibers. This helps to validate fiber alignment and serves as input data for numerical analysis with representative volume elements concatenating real fiber position and orientation with the three-dimensional stress tensor. Flexural and uniaxial tensional tests are performed combining multiple measuring techniques. Next to conventional displacement and strain measuring methods, sound emission analysis, in terms of quantitative event analysis and amplitude appraisal, and also high-resolution digital image correlation accompany the tests. Due to the electrical conductibility of carbon fibers, the materialâs resistivity could be measured during testing. All sensors detect the materialâs degradation behavior comparably, showing a strain-hardening effect, which results from multiple, yet locally restricted and distributed, microcracks arising in combination with plastic deformation