Preparation and physical properties of [PVA][0.7] [NaBr][0.3] [H[3]PO[4]][xM] solid acid membrane for phosphoric acid - Fuel cells

A solid acid membranes based on poly [vinyl alcohol] [PVA], sodium bromide [NaBr] and phosphoric acid [H[3]PO[4]] were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the [PVA][0.7][NaBr][0.3][H[3]PO[4]][xM] solid acid membranes where x =0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy [SEM] studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H[3]PO[4] concentration which it has been achieved to be of the order 4.3 x 10[-3] S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the [PVA][0.7][NaBr][0.3][H[3]PO[4]][xM] solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications

Indice de masa corporal. Adecuación energética e ingreso monetario familiar en estudiantes de enfermería de Quito

Se realiza un estudio transversal en 48 estudiantes femeninas de enfermería en las que se evalúa el índice de masa corpoal, la recomendación y adecuación energética individual según las normas FAO/OMS/UNU, y el ingreso familiar monetario. el promedio de índice de masa corporal es de 23.18, el 5.1 por ciento presenta déficit energético crónico y 23.1 por ciento obesidad de primer grado. El promedio de adecuación energética es 102,75 por ciento. El 35 por ciento de las alumnas se encuentra en el intervalo normal, el 37.5 por ciento por encima de la norma y el 27,5 por ciento por debajo de la norma de la adecuación energética. El 90.2 por ciento de las familias de las estudiantes no tienen acceso a la canasta familiar básica y el 46.3 por ciento no acceden a la canasta familiar de pobreza, establecidas por el Instituto Nacional de Estadísticas y Censos del Ecuador (INEC)...