Meeting of GOP Governors

An original ink cartoon depicting GOP governors as Abraham Lincoln look-alikes. The cartoon was originally published in the Boston Herald, 1994. Original ink cartoon by Jerry Holbert, originally published in Boston Herald,1994.https://scholarsjunction.msstate.edu/fvw-artifacts/2445/thumbnail.jp

Spectroscopic Studies of Low Temperature Polymer Electrolyte Membrane Fuel Cells

Fuel cell technology is one of the many competing technologies in the future of energy conversion and transport. With a growing demand for efficient, versatile and environmental friendly alternatives to the internal combustion engine, fuel cells show promising potential where batteries and grid-electricity are not available. For portable and transport applications, the low temperature Polymer Electrolyte Membrane Fuel Cell (PEMFC) is the most promising candidate. With a simple design, high power density and fast start-up, this technology have advanced quickly during the last decade with numerous field trials of several big automotive companies. However, two important challenges still remain. The current PEMFC system is still several times more expensive than competing technologies, even in serial production. Alternative cheaper materials, as well as improved design and manufacturing techniques can ultimately lower the cost. The durability of the PEMFC system must also be improved to compete with current technologies. The US Department of Energy estimates that the durability of a fuel cell stack need to reach no less than 5000 operating hours to be a competitive option. In the fuel cell stack, the membrane electrode assembly is known to be the limiting factor in durability tests. In this thesis, Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS) are used to detect and identify degradation mechanisms in membranes and electrodes used in PEMFC. The two main degradation mechanisms detected in poly-fluorosulfonic acid-based (PFSA) membranes are loss of active end groups and degradation of the polymer backbone (cutting of the polymer chain). Both these mechanisms are quantified by Raman spectroscopy. Degradation of the backbone, and carbon migration from the electrodes into the membrane are certain signs of an upcoming failure of the membrane, this degradation is measured in detail with micro-Raman spectroscopy. Finally, XPS is used to measure the oxidation state and particle distribution in the interface between the electrodes and the membrane. A lowered concentration of active catalyst in electrodes lowers the efficiency of the fuel cell and leads to rapid degradation

Diferenciación de mezcales de cuatro especies de agave usando FT-MIR y análisis estadístico multivariado

Fourier Transform Mid-Infrared (FT-MIR) spectroscopy and multivariate statistical analysis were used to differentiate mezcales elaborated with four agave species. The FT-MIR data matrix was subjected to spectral transformations using first and second derivatives. The Partial Least Squares (PLS)-Discriminant Analysis (DA) with the matrix transformed by the first and second derivative allowed the differentiation of mezcales. While Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) was more robust when it was analyzed with second-derivative data. Pairwise comparisons by OPLS-DA allowed mezcales to be correctly discriminated, mainly between Agave karwinskii and Agave potatorum (Q2 = 0.654 and p – value < 0.01; R2Y = 0.985 and p-value < 0.01) and between Agave angustifolia and Agave karwinskii (Q2 = 0.563 and p-value = 0.01; R2Y = 0.989 and p-value = 0.01). FT-MIR spectrophotometry and the PLS-Regression (PLS-R) were applied to predict the ethanol percentage (% v/v) of mezcales collected in 2022 based on the PLS-R model previously run on samples evaluated in 2021.Espectrofotometría Infrarroja en la región media con Transformada de Fourier (FT-MIR) y análisis estadístico multivariado fueron utilizados para diferenciar mezcales elaborados con cuatro especies de agave. La matriz de datos FT-MIR fue sometida a transformaciones espectrales mediante primera y segunda derivada. El Análisis Discriminante por Mínimos Cuadrados Parciales (PLS) a partir de datos transformados con primera y segunda derivada permitió la diferenciación de mezcales. En tanto, el Análisis Discriminante mediante Mínimos Cuadrados Parciales Ortogonales (OPLS-DA) fue más robusto cuando se analizó con los datos de segunda derivada. Las comparaciones pareadas mediante OPLS-DA permitió la discriminación adecuada de los mezcales, principalmente entre Agave karwinskii y Agave potatorum (Q2 = 0.654 and p-value < 0.01; R2Y = 0.985 and p-value < 0.01) y entre Agave angustifolia y Agave karwinskii (Q2 = 0.563 and p-value = 0.01; R2Y = 0.989 and p-value = 0.01). La espectrofotometría FT-MIR y la Regresión PLS (PLS-R) lograron predecir el porcentaje de etanol (% v/v) en los mezcales colectados en 2022 con base en el modelo PLS-R previamente generado con muestras evaluadas en 2021

Growth analysis and nutritional dynamics of fruits of two ilama (Annona diversifolia Saff.) genotypes native from Guerrero, Mexico

Antecedentes: La ilama (Annona diversifolia) es una especie frutal nativa de México, con Guerrero como el estado que posee la mayor superficie sembrada. La producción se concentra principalmente en pequeñas plantaciones de traspatio y zonas marginales. En frutales, los modelos de crecimiento de los frutos se clasifican principalmente en dos tipos: patrón sigmoide y doble sigmoide. El análisis del modelo de crecimiento y la dinámica nutrimental son herramientas clave para implementar estrategias de manejo orientadas a mejorar la calidad de los frutos. Objetivo: Caracterizar el patrón de crecimiento y la dinámica de acumulación de nutrimentos en frutos de dos genotipos nativos de ilama (pulpa blanca y pulpa vino), con el fin de generar información que sustente estrategias de manejo agronómico y valorización del cultivo. Se planteó la hipótesis de que ambos genotipos presentan un patrón de crecimiento doble sigmoide y que la acumulación de nutrimentos varía significativamente entre tejidos (pulpa, semilla, cáscara) y etapas fenológicas. Resultados: Las curvas de crecimiento mostraron un patrón doble sigmoide en ambos genotipos. Al final del desarrollo, el diámetro polar promedio fue de 11.8 cm y el ecuatorial de 11.1 cm. La acumulación de nutrimentos fue continua durante la temporada de crecimiento, con diferencias entre tejidos y nutrimentos específicos (Ca, N, P, K, Cu, Zn, Mn, Fe). Implicaciones: Esta información puede servir como base para diseñar estrategias de fertilización y manejo específicas para el cultivo de ilama, orientadas a mejorar su productividad y calidad poscosecha.Background: Ilama (Annona diversifolia) is a fruit species native to Mexico, with Guerrero being the state with the largest planted area. This production is mainly concentrated in small backyard plantations and marginal areas. In fruit trees, fruit growth patterns are classified into two main types: sigmoid and double sigmoid. Growth pattern analysis and nutrient dynamics are key tools for implementing management strategies aimed at improving fruit quality. Objective: To characterize the growth pattern and nutrient accumulation dynamics in fruits of two native ilama genotypes (white-fleshed and wine-fleshed), in order to generate information to support agronomic management strategies and crop valorization. It was hypothesized that both genotypes exhibit a double sigmoid growth pattern and that nutrient accumulation varies significantly between tissues (flesh, seed, peel) and phenological stages. Results: Growth curves showed a double sigmoid pattern in both genotypes. At the end of development, the average polar diameter was 11.8 cm and the equatorial diameter was 11.1 cm. Nutrient accumulation was continuous throughout the growing season, with differences between tissues and specific nutrients (Ca, N, P, K, Cu, Zn, Mn, Fe). Implications: This information can serve as a basis for designing specific fertilization and management strategies for ilama crops, aimed at improving their productivity and postharvest quality. Conclusion: This study demonstrates the importance of understanding ilama's nutritional dynamics and growth patterns for designing sustainable agronomic practices

Actividad antioxidante y citotóxica del aceite esencial de las hojas de laurel aromático (Litsea glaucescens Kunth)

Se utilizaron los métodos de FRAP y ABTS en microplaca para evaluar la actividad antioxidante y se empleó el bioensayo de Artemia salina para valorar la actividad citotóxica del aceite esencial de los aceites esenciales obtenidos de varias muestras de laurel aromático (Litsea glaucescens) especie vegetal forestal no maderable (PFNM) aprovechada ampliamente en México. Actualmente se encuentra registrado en la Norma Oficial Mexicana (NOM-059- SEMARNAT- 2019), con la categoría de P (en peligro de extinción) y se emplea para el tratamiento de enfermedades frías, dolores de cabeza y también la parálisis. La mayor capacidad antioxidante de los aceites esenciales analizados por ABTS correspondió a la muestra de Zongolica, Veracruz con 12.89 µmol ET/µL mientras que con el método FRAP el de mayor actividad antioxidante fue para una muestra obtenida del centro comercial Soriana, con 0.17149 µmol ET/mL. La muestra de aceite esencial obtenido del centro comercial Soriana en la prueba de Artemia salina exhibió la mayor actividad citotóxica con una CL50 de 53.8 μg/mL y la de menor actividad correspondió a la muestra de aceite preparado a partir de la colecta de Nopalillo, Hidalgo (Bosque de oyamel) con una CL50 de 451.6 μg/mL El análisis en Cromatografía   de gases acoplada a espectrometria de masas, evidenció la presencia de: 34.99 % de Eucaliptol (1,8-cineol), 7.45% de 1R-α-Pineno, 6.51% de L-Limoneno, 5.26 % de trans-dihidrocarvona, 4.62% de (-)-β-Pineno, 4.46 % de acetato de bormilo, 4.11 % de trans-4-Tujanol, 3.85 % de Canfeno, 3.06 % de γ-terpineno y 2.91% de Cariofileno, Estos resultados indican la posibilidad de utilizar los aceites esenciales de L. glaucescens, por sus propiedades antioxidantes y citotóxicas, ofreciendo una alternativa al uso como antimicrobiano

Spectroscopic Studies of Low Temperature Polymer Electrolyte Membrane Fuel Cells [Elektronisk resurs]

Fuel cell technology is one of the many competing technologies in the future of energy conversion and transport. With a growing demand for efficient, versatile and environmental friendly alternatives to the internal combustion engine, fuel cells show promising potential where batteries and grid-electricity are not available.For portable and transport applications, the low temperature Polymer Electrolyte Membrane Fuel Cell (PEMFC) is the most promising candidate. With a simple design, high power density and fast start-up, this technology have advanced quickly during the last decade with numerous field trials of several big automotive companies.However, two important challenges still remain. The current PEMFC system is still several times more expensive than competing technologies, even in serial production. Alternative cheaper materials, as well as improved design and manufacturing techniques can ultimately lower the cost. The durability of the PEMFC system must also be improved to compete with current technologies. The US Department of Energy estimates that the durability of a fuel cell stack need to reach no less than 5000 operating hours to be a competitive option. In the fuel cell stack, the membrane electrode assembly is known to be the limiting factor in durability tests. In this thesis, Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS) are used to detect and identify degradation mechanisms in membranes and electrodes used in PEMFC. The two main degradation mechanisms detected in poly-fluorosulfonic acid-based (PFSA) membranes are loss of active end groups and degradation of the polymer backbone (cutting of the polymer chain). Both these mechanisms are quantified by Raman spectroscopy. Degradation of the backbone, and carbon migration from the electrodes into the membrane are certain signs of an upcoming failure of the membrane, this degradation is measured in detail with micro-Raman spectroscopy. Finally, XPS is used to measure the oxidation state and particle distribution in the interface between the electrodes and the membrane. A lowered concentration of active catalyst in electrodes lowers the efficiency of the fuel cell and leads to rapid degradation

Meeting of GOP Governors

An original ink cartoon depicting GOP governors as Abraham Lincoln look-alikes. The cartoon was originally published in the Boston Herald, 1994. Original ink cartoon by Jerry Holbert, originally published in Boston Herald,1994.https://scholarsjunction.msstate.edu/fvw-cartoons/1062/thumbnail.jp