Síntesis y caracterización de Nanorods de oro con potenciales aplicaciones en terapia fototérmica

Describe la aplicación de la nanotecnología para el diagnóstico, tratamiento y prevención de enfermedades cancerígenas. Contrasta las ventajas de esta aplicación con los tratamientos convencionales

Efecto de la concentración de Fe en las tensiones residuales de las películas delgadas de ZnO crecidas por rociado pirolítico

En el presente trabajo de investigación se evaluó el efecto de la concentración de Fe sobre las tensiones residuales de las películas delgadas de Zn1-xFexO (x: 5, 10, 15 y 20%), crecidas por rociado pirolitico sobre sustratos de vidrio a la temperatura de 480°C. Como precursores se usaron una solución etanólica de acetato de zinc di-hidratado [Zn (CH3CO2)2.2H2O]-1,0 M y una solución acuosa de cloruro de hierro hexa-hidratado [FeCl3.6H2O]-1,0 M. La presión y flujo de aire durante el proceso de crecimiento, se fijaron en 2 kPa y 9 L/min, respectivamente. Los patrones de difracción de rayos X revelaron una estructura wurtzita típica del ZnO sin presencia de otras fases en todas las concentraciones de Fe estudiadas, confirmando la sustitución de iones de Fe+2 por iones de Zn+2. La incorporación de Fe (5-20%) revelaron bajas tensiones compresivas en el modelo uniaxial y altas tensiones tensiles en el modelo biaxial

Influencia de la temperatura de síntesis de la capa SnO2 sobre la transmitancia óptica del sistema vidrio-SnO2-CdS

The influence of the synthesis temperature on the optical transmittance of the glass / SnO2 / CdS structure was evaluated, for which samples of thin films of SnO2 on glass were prepared, by the Spray Pyrolysis method at temperatures (340 ° C, 360 ° C, 380 ° C and 400 ° C) ± 10 ° C; then these served as substrate for the deposition of CdS films by the method deposited by chemical bath at (75 ± 2) ° C. The diffractograms for the SnO2 films showed a tetragonal crystalline structure showing that the best crystalline structure is the film whose synthesis temperature was 380 ° C. The CdS film showed a cubic structure. Within the considered synthesis temperature range, it turned out that the optical transmittance of the SnO2 films varied between 85 and 90%. Likewise, by means of atomic outside microscopy (AFM), the square average surface roughness (Rq) was evaluated as a function of the synthesis temperature, which resulted between approximately 9 to 20 nm. for the glass-SnO2-CdS system, the highest optical transmittance ranged from 50 to 70%, in the film synthesized at 380 ° C.Se evaluó la influencia de la temperatura síntesis sobre la transmitancia óptica de la estructura vidrio/SnO2/CdS, para lo cual se preparó muestras de películas delgadas de SnO2 sobre vidrio, por el método de Spray Pyrolysis a las temperaturas (340 °C, 360°C, 380°C y 400 °C) ± 10 °C; luego éstas sirvieron como sustrato para la deposición de películas de CdS por el método deposito por baño químico a (75 ± 2) °C. Los difractogramas para las películas de SnO2, mostraron una estructura cristalina tetragonal evidenciando que la mejor estructura cristalina es la película cuya temperatura de síntesis fue de 380 °C. La película de CdS mostro una estructura cúbica. Dentro del rango de temperatura de síntesis considerado, resultó que la transmitancia óptica de las películas de SnO2 varió entre 85 y 90 %.  Así mismo, mediante microscopía de fuera atómica (AFM) se evaluó la rugosidad superficial promedio cuadrado (Rq) en función de la temperatura de síntesis la que resultó entre 9 a 20 nm aproximadamente. para el sistema vidrio-SnO2-CdS, la mayor transmitancia óptica varió entre 50 a 70 %, en la película sintetizada a 380°C

Propiedades multiferroicas de la estructura multicapas BiFeO3 /CoFe2 O4 a temperatura ambiente

Las películas multicapa BiFeO3 /CoFe2 O4 se depositaron mediante recubrimiento por rotación sobre 3 2 4 sustratos de Pt (Pt / TiO2 / SiO2 / Si) y se recocieron a 700, 725 y 750 ° C. El precursor de BiFeO3/CoFe2O4 para la estructura de multicapas se sintetizó por el método de solución química. Los patrones de difracción de rayos X del sistema de multicapas revelaron la estructura de tipo compuesto. La corriente de fuga se encontró a menos de 10 Amp en el campo eléctrico por debajo de 100 kV / cm, que muestra el -6 comportamiento óhmico de BiFeO /CoFe O . La constante dieléctrica disminuye al aumentar en el rango de 3 2 4 frecuencia 103-106 Hz. El sistema BiFeO /CoFe O muestra la coexistencia de polarización ferroeléctrica 3 2 4 (Pr) = 65 y 51 μC / cm2 y magnetización (Mr) = 102 y 47 emu / cm3 a temperatura ambiente. Las respuestas ferromagnéticas y ferroeléctricas observadas en el sistema de multicapas pueden ser útiles para dispositivos bifuncionales

Influence of operating temperature on the activation efficiency of Li-ion cells with xLi2MnO3-(1-x)LiMn0.5Ni0.5O2 electrodes

In this study, the effect of operating temperature at 55 °C on xLi2MnO3-(1-x)LiMn0.5Ni0.5O2 electrodes during the charge/discharge process at different current densities was investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for structural and morphological analysis of the fabricated cathode materials, while charge-discharge curves and differential capacity were used to study the electrochemical behavior. Results confirm the formation of the structures with two phases associated with the components of the layered material. It was found that at 55 °C, a capacity higher than 357 mAh g-1 could be achieved at a voltage of 2.5-4.8 V vs. Li/Li+, which was larger than the capacity achieved at room temperature. At 55 °C, a change in valence could be observed during charging and discharging due to the change in the position of the peaks associated with Mn and Ni, highlighting cathodic material with x = 0.5 as the material that retains the layered structure at this temperature. This work confirms the good performance of electrodes made with this material at elevated temperatures and gives a better understanding of its electrochemical behavior

Increase in Electrical Parameters Using Sucrose in Tomato Waste

"The use of organic waste as fuel for energy generation will reduce the great environmental problems currently caused by the consumption of fossil sources, giving agribusiness companies a profitable way to use their waste. In this research, tomato waste with different percentages of sucrose (0-target, 5, 10, and 20%) was used in microbial fuel cells manufactured on a laboratory scale with zinc and copper electrodes, managing to generate maximum peaks of voltage and a current of 1.08 V and 6.67 mA in the cell with 20% sucrose, in which it was observed that the optimum operating pH was 5.29, while the MFC with 0% (target) sucrose generated 0.91 V and 3.12 A on day 13 with a similar pH, even though all the cells worked in an acidic pH. Likewise, the cell with 20% sucrose had the lowest internal resistance (0.148541 ± 0.012361 KΩ) and the highest power density (224.77 mW/cm2 ) at a current density of 4.43 mA/cm2 , while the MFC with 0% sucrose generated 160.52 mW/cm2 and 4.38 mA/cm2 of power density and current density, respectively, with an internal resistance of 0.34116 ± 0.2914 KΩ. In this sense, the FTIR (Fourier-transform infrared spectroscopy) of all the substrates used showed a high content of phenolic compounds and carboxylate acids. Finally, the MFCs were connected in a series and managed to generate a voltage of 3.43 V, enough to light an LED (green). These results give great hope to companies and society that, in the near future, this technology can be taken to a larger scale.

Increase in Electrical Parameters Using Sucrose in Tomato Waste

The use of organic waste as fuel for energy generation will reduce the great environmental problems currently caused by the consumption of fossil sources, giving agribusiness companies a profitable way to use their waste. In this research, tomato waste with different percentages of sucrose (0-target, 5, 10, and 20%) was used in microbial fuel cells manufactured on a laboratory scale with zinc and copper electrodes, managing to generate maximum peaks of voltage and a current of 1.08 V and 6.67 mA in the cell with 20% sucrose, in which it was observed that the optimum operating pH was 5.29, while the MFC with 0% (target) sucrose generated 0.91 V and 3.12 A on day 13 with a similar pH, even though all the cells worked in an acidic pH. Likewise, the cell with 20% sucrose had the lowest internal resistance (0.148541 ± 0.012361 KΩ) and the highest power density (224.77 mW/cm2) at a current density of 4.43 mA/cm2, while the MFC with 0% sucrose generated 160.52 mW/cm2 and 4.38 mA/cm2 of power density and current density, respectively, with an internal resistance of 0.34116 ± 0.2914 KΩ. In this sense, the FTIR (Fourier-transform infrared spectroscopy) of all the substrates used showed a high content of phenolic compounds and carboxylate acids. Finally, the MFCs were connected in a series and managed to generate a voltage of 3.43 V, enough to light an LED (green). These results give great hope to companies and society that, in the near future, this technology can be taken to a larger scale. View Full-Tex

Generation of Electricity Through Papaya Waste at Different pH

A large amount of fruit waste is being a great environmental and social problem due to a lack of adequate storage. Among the most abundant waste is papaya, due to its high consumption in various varieties. These wastes can generate bioelectricity through organic waste, being an important parameter the pH. In this research, lowcost laboratory-scale microbial fuel cells were fabricated, using papaya waste as fuel at different pH (4, 5.73, 7, and 9) to obtain the optimum operating pH. It was possible to observe the maximum values of electric current and voltage of 17.97 mA and 1.02 V on days 16 and 14, in the cell with pH 7; while the cell with pH was the one that showed the lowest values. The electrical conductivity values increased from the first day, observing a maximum peak of 172.50 mS/cm for the cell with pH 7. However, the internal resistance values were low, the maximum value being for the cell with pH 4 (234.61 ± 34 Ω) and the minimum for the cell with pH 7 (46.543 ± 3.6Ω). In the same way, the maximum power density was for the cell with pH 7 of approximately 645.74 ± 33.64 mW/cm2 and a current density of 5.42 A/cm2

Electric current generation by increasing sucrose in papaya waste in microbial fuel cells

The accelerated increase in energy consumption by human activity has generated an increase in the search for new energies that do not pollute the environment, due to this, microbial fuel cells are shown as a promising technology. The objective of this research was to observe the influence on the generation of bioelectricity of sucrose, with different percentages (0%, 5%, 10% and 20%), in papaya waste using microbial fuel cells (MFCs). It was possible to generate voltage and current peaks of 0.955 V and 5.079 mA for the cell with 20% sucrose, which operated at an optimal pH of 4.98 on day fifteen. In the same way, the internal resistance values of all the cells were influenced by the increase in sucrose, showing that the cell without sucrose was 0.1952 ± 0.00214 KΩ and with 20% it was 0.044306 ± 0.0014 KΩ. The maximum power density was 583.09 mW/cm2 at a current density of 407.13 A/cm2 and with a peak voltage of 910.94 mV, while phenolic compounds are the ones with the greatest presence in the FTIR (Fourier transform infrared spectroscopy) absorbance spectrum. We were able to molecularly identify the species Achromobacter xylosoxidans (99.32%), Acinetobacter bereziniae (99.93%) and Stenotrophomonas maltophilia (100%) present in the anode electrode of the MFCs. This research gives a novel use for sucrose to increase the energy values in a microbial fuel cell, improving the existing ones and generating a novel way of generating electricity that is friendly to the environment.Campus Trujill

Effect of x on the Electrochemical Performance of Two-Layered Cathode Materials xLi2MnO3–(1−x)LiNi0.5Mn0.5O2

In our study, the cathodic material xLi2MnO3–(1−x)LiNi0.5Mn0.5O2 was synthesized by means of the co-precipitation technique. The effect of x (proportion of components Li2MnO3 and LiNi0.5Mn0.5O2) on the structural, morphological, and electrochemical performance of the material was evaluated. Materials were structurally characterized using X-ray diffraction (XRD), and the morphological analysis was performed using the scanning electron microscopy (SEM) technique, while charge–discharge curves and differential capacity and impedance spectroscopy (EIS) were used to study the electrochemical behavior. The results confirm the formation of the structures with two phases corresponding to the rhombohedral space group R3m and the monoclinic space group C2/m, which was associated to the components of the layered material. Very dense agglomerations of particles between 10 and 20 µm were also observed. In addition, the increase in the proportion of the LiNi0.5Mn0.5O2 component affected the initial irreversible capacity and the Li2MnO3 layer’s activation and cycling performance, suggesting an optimal chemical ratio of the material’s component layers to ensure high energy density and long-term durability