Caracterización morfoagronómica de cacao criollo (Theobroma cacao L.) y su incidencia en la selección de germoplasma promisorio en áreas de presencia natural en El Salvador

En El Salvador el cultivo de cacao, se proyecta como un rubro nuevo de producción agrícola tanto en el ámbito nacional como internacional, constituyendo una oportunidad para el desarrollo económico de productores interesados en este cultivo; por tal motivo se realizó un proceso de prospección de esta especie entre el período de octubre 2013 a junio 2014, iniciando colectas de frutos y material vegetativo de cacao en áreas de presencia natural de la especie. El objetivo fue identificar in situ árboles de cacao para la caracterización morfoagronómica, utilizando descriptores adaptados al catálogo de cultivares de cacao del Perú, CATIE y FEDECACAO, se identificaron zonas donde había presencia de la especie, en los municipios de Caluco, en Sonsonate; el Salitre, Ciudad Delgado y Planes de Renderos, San Salvador; Tenancingo, Cuscatlán; San Pedro Nonualco y Santa María Ostuma, La Paz; Ciudad Victoria, Cabañas y Jucuapa, Usulután. Se caracterizaron 21 árboles; cada uno con sus respectivos atributos cualitativos y cuantitativos como: altura del árbol, forma y tamaño de hojas, frutos, semillas y flores. Cada árbol muestreado, fue georeferenciado, con el fin de ubicarlo y generar el mapa de distribución de los mismos a nivel nacional. Asimismo, en el laboratorio de Química Agrícola de la Facultad de Ciencias Agronómicas, se realizó análisis bromatológicos a muestras de frutos, determinando: grasa, proteína, ceniza, hierro, zinc, humedad total, humedad parcial y materia seca. Como resultados de esta investigación, se inició una colección de cacao con atributos sobresalientes, los mayores porcentajes de grasa lo obtuvieron los árboles codificados como: UES-PDP-19, con 56.4%; UES-SPN-7 con 50.67% y UES-SPN-8 con 50.29%; y los mayores porcentajes de proteína se identificaron para las accesiones, UES-SLT-16, con 27.38%; UES-TNG-18, con 23.36%; y UES-SAL-3 con 21.31%; parámetros que son importantes al momento de hacer programas de producción, mejoramiento genético y en la preservación de este germoplasma

Dielectric and ac conduction properties of zinc phthalocyanine (ZnPc) thin films

The dielectric responses of zinc phthalocyanine (ZnPc) thin films, deposited using the vacuum evaporation technique, were studied as functions of frequency and temperature. The conductivity of the deposited films decreases with increase in temperature. The dielectric studies clearly indicated that the Debye type of polarization exists in these films. The relaxation phenomena have been confirmed from the Cole-Cole plot. The relaxation times have been evaluated from the plot and were found to be (τa) 0.0137 and 0.0106 s at 303 and 403 K , respectively. The prevailing conduction mechanism in ZnPc films, under an ac field, was found to be electronic hopping. The activation energy was evaluated from the Arrhenius plot and was found to be 1.28 eV . Based on the structure, and with the help of quantum mechanics calculations, the electronic structure and behavior that upheld our experimental results were identified

Characterization of zinc phthalocyanine (ZnPc) for photovoltaic applications

Zinc phthalocyanine (ZnPc) is a promising candidate for solar-cell applications, because it is easily synthesized and is non-toxic to the environment. Recently, phthalocyanine (Pc) was considered by many researchers as the active part in all-organic solar cells, i.e. plastic solar cells. It is a self-assembling liquid crystal developed from a common deep-blue-green pigment. It exhibits a characteristic structural self-organization, which is reflected in an efficient energy migration in the form of extinction transport. In this paper we have report structural, surface morphological, optical and thermal properties of flash-evaporated zinc phthalocyanine thin films. The samples were prepared by using a vacuum coating unit on well-cleaned glass substrates under a pressure of 7×10-6 Torr. A constant rate of evaporation (1 Å/s) was maintained throughout the evaporation of the ZnPc thin films. A rotary drive was employed to obtain uniform thickness during the evaporation. Thicknesses of the films were monitored by a quartz-crystal thickness monitor and were cross verified by the multiple-beam interferometry technique. The X-ray-diffraction pattern reveals the crystalline nature of the films deposited at higher substrate temperatures. Scanning electron microscope and scanning probe microscope nanoscope studies were carried out to determine the surface uniformity and homogeneity of the films for interfacing and application purposes. All the films were found to possess small crystallites less than 100 nm in size. The optical transmittance measurements were carried out using a spectrophotometer in the visible region (400–800 nm) and the films were found to be absorbing in nature. The band gap of the ZnPc thin films is 1.97 eV and the optical transition was found to be direct and allowed. The absorption coefficient, extinction coefficient and refractive index of the ZnPc films were evaluated and the results are discussed. Differential scanning calorimetry studies of ZnPc films were carried out and a phase transition from α to β was observed at 538 K

On a Probable Catalytic Interaction between Magnetite (Fe3O4) and Petroleum

Magnetic and nonmagnetic iron compounds were detected as part of asphaltene deposits formed on tubing wall surface. To shed light on the probable role of the iron compounds in the formation of such deposits, magnetite (Fe3O4), one of the intrinsic components of the iron oxide multilayer scale of any carbon steel surface, was contacted with crude oil at 170 °C, a temperature similar to that of the bottom well, and subsequently aged at room temperature. Characterization of the samples was made by using XRD, Mo¨ssbauer, IR, TGA, EDS, and microscopic (SEM and TEM) techniques. Small amounts of new iron phases, magnetic (oxidized magnetite) and nonmagnetic (iron oxyhydroxides), an increase in the content of CdC and C-O bonds of the organic phase, and an increase of the thermal stability of the organic phase indicated the formation of iron complexes of Fe ions and FeOOH with the oxygen functionalities