Abstract Distichlis spicata is a gramineous halophyte species that grow around the coastal areas. The objective of the study was to identify the modifications in the anatomical structure of stomates of the D. spicata leaf epidermis, cultivated with irrigation and without irrigation conditions. Two populations were selected, 1) plants of D. spicata with irrigation and 2) plants of D. spicata without irrigation. Ten plants per replication were selected from each population, and from each selected plant, the fourth leaf was taken. Each leaf was cut longitudinally into four segments which were dried and analyzed using an Electronic Scanning Microscope. The variables measured were the stomatal density, length, and width of stomates and pores, the stomatal area, the proportion of the pore area concerning the size of the stomata, and the stomata proportion per surface. The results showed that D. spicata populations with irrigation and without irrigation showed anatomical modifications in the structure of stomates in the adaxial epidermis but not in the abaxial epidermis. In the adaxial epidermis, the plants with irrigation showed higher values of stoma length, stoma width, stoma area and pore length, while plants without irrigation showed higher values of proportion pore/stoma and stomatal density. The D. spicata plants without irrigation showed small stomates than plants with irrigation, also, the plants without irrigation, increased the accumulation of salt crystals in the abaxial epidermis.

Resumen Distichlis spicata es una especie de gramínea halófita que crece en las zonas costeras. El objetivo del estudio fue identificar las modificaciones en la estructura anatómica de estomas de la epidermis foliar de D. spicata, cultivadas con riego y sin riego. Se seleccionaron dos poblaciones, 1) plantas de D. spicata con riego y 2) plantas de D. spicata sin riego. De cada población se seleccionaron 10 plantas por repetición y de cada planta seleccionada se tomó la cuarta hoja. Cada hoja se cortó longitudinalmente en cuatro segmentos que se secaron y analizaron utilizando un microscopio electrónico de barrido. Las variables medidas fueron la densidad estomática, largo y ancho de estomas y poros, el área estomática, la proporción del área de poros con respecto al tamaño de los estomas y la proporción de estomas por superficie. Los resultados mostraron que la población de D. spicata con riego y sin riego mostraron modificaciones anatómicas en la estructura de los estomas en la epidermis adaxial pero no en la epidermis abaxial. En la epidermis adaxial, las plantas con riego presentaron valores más altos de longitud de estoma, ancho de estoma, área de estoma y longitud de poro, mientras que las plantas sin riego mostraron valores más altos de proporción poro/estoma y densidad estomática. Las plantas de D. spicata sin riego presentaron estomas más pequeños respecto a las plantas con riego; además, las plantas sin riego incrementaron la acumulación de cristales de sal en la epidermis abaxial.

Abstract Purpose: To analyze and compare the anatomy and composition of the seed coat from E. cyclocarpum seeds from two different origins and harvest years, and from 12 other legume species, through images obtained from a scanning electron microscope (SEM) as well as to perform a germination test and a proximal analysis of the first species. Methodological design: Samples of the E. cyclocarpum seed coat from two different provenances and years of harvest (1983 and 2019) were observed in an electronic microscope along with 12 other legume species. Scarification treatments for a germination test and a proximal analysis were conducted for E. cyclocarpum seeds collected in 2019. Results: The number of cell layers present in all of the species ranges from four to eight. The statistical analysis of germination was significant (p <0.0001) among the treatments; the one with the highest germination was sanding. The presence of a high percentage of lignin (L), neutral detergent fiber (NDF), acid detergent fiber (FDA), and nitrogen-free extract (ELN) in the seed coat was found. Research limitations: To obtain a seed coat sample, it is necessary to consider the location on the seed from which it is taken since the thickness of the seed coat can vary. Findings: The cell layers present in the seed coat are cuticle, macrosclereids, osteosclereids, and parenchyma (spongy, palisade, compact); It was observed that E. cyclocarpum has seven and eight layers while in the rest of the species four to eight. The presence of cell layers and lignin in the seed coat of E. cyclocarpum determines its physical dormancy.

Resumen Objetivo: analizar y comparar la anatomía y composición de la cubierta seminal en semillas de E. cyclocarpum de dos procedencias y años de recolección distintos, y de otras 12 especies de leguminosas, mediante el uso de imágenes obtenidas en un microscopio electrónico de barrido (MEB); así como realizar una prueba de germinación y un análisis proximal de la primera especie. Diseño metodológico: se observaron en un MEB muestras de cubierta seminal de E. cyclocarpum de dos procedencias y años de recolección distintos (1983 y 2019). También fueron observadas 12 especies de leguminosas. En semillas de E. cyclocarpum recolectada en 2019 se emplearon tratamientos de escarificación para realizar un estudio de germinación y también se hizo un análisis proximal. Resultados: el número de capas celulares presentes en todas las especies va de cuatro a ocho. El análisis estadístico de germinación fue significativo (p<0.0001), entre los tratamientos, el de mayor germinación fue el lijado. Se halló un alto porcentaje de lignina (L), fibra detergente neutra (FDN), fibra detergente ácida (FDA) y extracto libre de nitrógeno (ELN) en la cubierta seminal. Limitaciones de la investigación: para la obtención de la muestra de cubierta seminal es necesario considerar la parte de la semilla de donde se toma, ya que el grosor de esta puede variar. Hallazgos: las capas celulares presentes en la cubierta seminal son cutícula, macroesclereidas, osteoesclereidas, parénquima (esponjoso, en empalizada, compacto). E. cyclocarpum tiene siete y ocho capas, en el resto de las especies se observaron de cuatro a ocho capas. La presencia de capas celulares y lignina en la cubierta seminal (base seca) de E. cyclocarpum determina su latencia física.

RESUMEN: Propósito: El sellado de la interface de la conexión implante-pilar es esencial para el éxito a largo plazo de la restauración implantosoportada. El objetivo de este estudio fue analizar el comportamiento mecánico y el efecto de la fatiga cíclica antes y después en el sellado de la conexión implante-pilar de acuerdo a la ténica de fabricación del pilar. Materiales y Métodos: Pilares mecanizados de titanio (DENTIS), pilares calcinables colados con aleación Niquel-Cromo (VeraBond II) y pilares fresados de Zirconia (Zirkonzahn) fueron evaluados. Los implantes y pilares atornillados se sometieron a una carga de 133 N a una frecuencia de 19.1 Hz durante 200 000 ciclos. El microgap fue medido con el Microscopio Electrónico de Barrido y la distribución del esfuerzo de compresión por el método tridimensional de Elemento Finito (EF). Los valores del microgap de los pilares mecanizados fueron de 1.62μm y 1.92μm, en los pilares calcinables fue de 14.14μm y 20.15μm, y los pilares fresados fue de 14.18μm y 28.44 μm antes y después de la fatiga cíclica, respectivamente. Los pilares calcinables y lo mecanizados mostraron diferencia estadísticamente significativa antes y después de la fatiga cíclica (p≤0.05). El análisis por EF mostró que las áreas críticas del esfuerzo de compresión estaban localizadas en la conexión implante-pilar, aumentando en los pilares calcinables y disminuyendo en los pilares fresados y en los mecanizados. Conclusión: La fatiga cíclica ejerce un efecto sobre las dimensiones del microgap en la interface implante-pilar antes y después de la carga cíclica; este microgap depende del tipo de material y de la técnica de fabricación del pilar.

ABSTRACT: Purpose: The seal of the interface formed at the implant-abutment connection is essential for the long-term success of the implant-supported restoration. The aim of this study was to analyze the mechanical behavior and the effect of cyclic fatigue before and after in the marginal fit of implant-abutment according to the manufacturing technique of the abutment. Materials and methods: Machined titanium abutments (DENTIS), cast abutments with Nickel-Chromium alloy (VeraBond II), and manufacturing custom milled Zirconia abutments (Zirkonzahn) were evaluated. The implant-abutment assemblies were subjected to cyclic loads of 133 N at a frequency of 19.1 Hz for 200,000 cycles. The microgap was measured using Scanning Electronic Microscope and the distribution of compressive stress by the three-dimensional Finite Element (FE) method. Results: The microgap measurement values of the machined abutments were 1.62μm and 1.92μm, cast abutments were 14.14 μm, and 28.44 μm, and the milled abutments were 14.18μm and 20.15μm before and after cyclic fatigue, respectively. Only the cast abutments and the machined abutments showed a statistically significant difference before and after cyclic fatigue (p≤0.05). The FE analysis showed that the critical areas of compressive stress were located at the implant-abutment connection, increasing in the cast abutments and decreasing in the milled and the machined abutments. Conclusion: Cyclic fatigue exerts an effect on the dimensions of the microgap at the implant-abutment interface before and after loading; this microgap depends of the type of abutment material and the manufacturing technique.

Abstract This research shows two new microalloyed steels with niobium (Nb) for railroad wheels (Nb1 and Nb2) applied on heavy haul transportation (load over 30 tons/axle). The steels have mixed microstructure composed of pearlite and bainite (finished wheel rim section), and another one composed of martensite with bainite (black wheel section removed on machining) obtained by continuous cooling quenching heat treatment followed by tempering. The bainitic and martensitic microstructure are sensitive to the temper embrittlement phenomenon; therefore, knowing the embrittlement temperature range of these steels is mandatory in order to avoid such an event in the tempering process. Charpy specimens were extracted from the rim of railroad wheels, austenitized (860 ºC), quenched in water for four minutes, and tempered at different temperatures to obtain the embrittlement curve. Three materials were compared: AAR (Association of American Railroads) Class C steel with pearlitic microstructure (not sensitive to embrittlement), Nb1, and Nb2 microalloyed steels with martensitic, bainitic, and pearlitic microstructures. The microalloyed steels have niobium (Nb), molybdenum (Mo), and silicon (Si) addition. The effect of Si content and the microstructure (analyzed by Scanning Electronic Microscope (SEM)), regarding the embrittlement phenomenon, was also studied. The microstructure of Nb2 steel was analyzed by with Transmission Electronic Microscope (TEM) for improving its characterization.

ABSTRACT In this work we study the effects on the porosity and microhardness properties when using different tetragonal phase zirconium oxide stabilized with yttrium oxide as diameters powders (less than 40 μm, between 40 to 60 μm and greater than 80 μm) to deposit in the upper layer of a TBC system (thermal barrier coating) of double layer formed by NiCoCrAlY and tetragonal phase zirconium oxide stabilized with yttrium oxide using the plasma spray process, in order to find the suitable powder and feasible to use as top layer. To this end, instruments such as TESCAN Vega SB scanning electron microscope with INCA Energy dispersive microanalyzer were used, with which it was possible to detect the porosity in different areas of evaluation of the upper layer and the Vickers durometer to measure the microhardness. Verifying that with particle diameters smaller than 40 μm, the aforementioned properties are adequate for the conformation of the tetragonal phase zirconium oxide stabilized with yttrium oxide such as top layer.

RESUMEN En este trabajo se estudian los efectos en las propiedades de porosidad y microdureza al usar distintos diámetros de polvos de óxido de circonio en fase tetragonal estabilizado con óxido de itrio (menores a 40 µm, entre 40 a 60 µm y mayores a 80 µm) a depositar en la capa superior de un sistema TBC (barrera de protección térmica) de doble capa conformado por NiCoCrAlY y óxido circonio en fase tetragonal estabilizado con óxido de itrio usando el proceso de pulverización en plasma, con el propósito de encontrar el polvo adecuado y factible de usar como capa superior. Para ello se utilizaron instrumentos como el Microscopio electrónico de barrido TESCAN Vega SB con microanalizador dispersivo INCA Energy electronic microscope con el cual se pudo detectar la porosidad en distintas zonas de evaluación de la capa superior y el durómetro de Vickers para medir la microdureza. Comprobándose que con diámetros de partículas menores a 40 µm las propiedades anteriormente mencionadas son las adecuadas para la conformación de la capa superior de óxido circonio en fase tetragonal estabilizado con oxido de itrio.

Resumo Peltaea chiquitana tem sido um nome de identidade duvidosa devido à descrição original incompleta e aos materiais originais não possuírem frutos. Estudos recentes de herbários e trabalhos de campo realizados trouxeram novos dados sobre essa espécie. Assim, apresentamos uma redescrição de P. chiquitana, incluindo a coluna, fruto e semente pela primeira vez. A extensão da distribuição geográfica de P. chiquitana é apresentada com base nos primeiros registros para o Brasil. Além disso, são apresentadas ilustrações, microscopia eletrônica de varredura, mapa de distribuição e estado de conservação.

Abstract Peltaea chiquitana has been a name of dubious identity due to the incomplete original description and original materials lacking fruits. Recent herbaria and field work studies have uncovered new data for this species. Thus, we present a redescription of P. chiquitana, including, for the first time, details of column, fruit, and seed morphology. An extended geographical distribution of P. chiquitana is presented, based on the first records of the species to Brazil. Furthermore, line drawings, scanning electronic microscope photographs, a distribution map, and a conservation assessment are presented here.

Resumo Desde a fundação do Centro Malacológico em 1980, a Universidad Central Americana (UCA), Manágua-Nicarágua, vem acompanhando e coletando a população de moluscos marinhos, terrestres, fluviais e lagoas do país. Muitos espécimes foram fotografados pelo microscópio eletrônico de varredura (SEM) e, em um deles, a observação do periostracum peludo revela uma população aparentemente próspera de protistas de minuto em possível simbiose com o hospedeiro. A ampliação adequada e a comparação com estudos anteriores permitem a determinação dessas diatomáceas, amebas testaceas, leveduras, phacus, esporos e outros organismos indeterminados que ocorrem em florestas tropicais em rochas, árvores e folhas. Aqui estão as diatomeas e outros organismos pela primeira vez detectados no periostracum de um molusco tropical.

Abstract Since the foundation of the Malacological Center in 1980, Universidad Centro Americana (UCA), Managua-Nicaragua, has been monitoring and collecting the marine, terrestrial, fluvial and lake mollusk population of the country. Many specimens have been photographed by Scanning Electronic Microscope (SEM), and in one of these, observation of the hairy periostracum reveals a seemingly thriving population of minute protists in possible symbiosis with their host. Adequate magnification and comparison with previous studies allowed the determination of these hosts as diatoms, testaceous amoebae, yeast, phacus, spores and other undetermined organisms which occur in tropical forests on rocks, trees and leaves. Here illustrated are diatoms and other organisms detected for the first time on the periostracum of a tropical rainforest mollusk.

Resumen Películas delgadas de ZrTiSiNiN fueron depositadas sobre sustratos de vidrio y silicio mediante cosputtering reactivo con magnetrón usando blancos de Ti5Si2, Zr. En esta investigación se varío el contenido de Ni en los recubrimientos mediante la adición de cubos de Ni ubicados sobre el blanco de Zr. La morfología superficial, la estructura cristalina y el espesor de las películas fueron evaluadas mediante microscopía electrónica de barrido (SEM), difracción de rayos X (XRD) e interferometría respectivamente. La resistividad eléctrica se midió mediante el método de cuatro puntas y sus propiedades ópticas se caracterizaron por espectroscopía ultravioleta / visible (UV/Vis). Con base en los resultados de XRD se observó que el Níquel actúa como refinador de grano al lograr disminuir el tamaño de cristalito de 27 nm hasta 15 nm cuando la concentración de Níquel aumenta de 0 at% a 6,8 at%. Tanto la resistividad eléctrica y el "band gap" óptico de los recubrimientos aumentaron con la disminución del tamaño del cristalito como resultado del aumento de la densidad de límites de grano y del efecto de confinamiento cuántico.

Abstract Thin films of ZrTiSiNiN have been deposited onto a glass and silicon substrates by reactive magnetron co-sputtering of pure Ti5Si2, Zr alloy targets. In this investigation was located Ni pieces on Zr target in order to change the Ni amount in the films. The surface morphology and crystalline structure of the films were investigated by scanning electronic microscope (SEM), X-ray diffraction (XRD) and interferometry respectively. The electrical resistivity was measured by the four-point probe method and their optical properties were characterized by ultraviolet/visible (UV/ Vis) spectroscopy. XRD results showed that nickel works as a grain refiner because the crystallite size is reduced from 27 nm to 15 nm when the Ni concentration increases from 0 to% to 6.8 to%. Both the electrical resistance and the optical "band gap" of the coatings increased with the decrease in crystallite size because of the increase in the density of grain boundaries and the quantum confinement effect.

ABSTRACT Natural fibers today play an important role as reinforcement in composite materials. The objective of this work was to obtain the adequate parameters for the manufacture of hybrid composites with curauá fibers and graphene oxide nanometric particles in the Polyester matrix, looking for the optimal variant of greater resistance to traction and flexion. The curauá fibers were treated with different NaOH solutions and different immersion times, different fiber contents and different graphene oxide contents were used. In the work Taguchi method was used to determine the quantity of necessary experiments and to evaluate the results. Micrographs were made using the Electronic Scanning Microscope and X-ray diffraction to determine the effectiveness of the treatments performed. Mechanical tests of traction and flexion were carried out and the results showed an increase of the resistance to average traction of 156% in relation to pure Polyester and a 186% of the resistance to flexion.

RESUMEN Las fibras naturales hoy en día juegan un papel importante como refuerzo en materiales compuestos. El objetivo de este trabajo fue obtener los parámetros adecuados para la fabricación de compuestos híbridos con fibras de curauá y partículas manométricas de óxido de grafeno en matriz de Poliéster buscando la variante óptima de mayor resistencia a tracción e flexión. Las fibras de curauá se trataron con diferentes disoluciones de NaOH y diferentes tiempos de inmersión, fueron utilizados diferentes contenidos de fibra y diferentes contenidos de óxido de grafeno. En el trabajo fue utilizado o método Taguchi para determinar los experimentos necesarios e para evaluar los resultados. Se realizaron micrografías utilizando o Microscopio Electrónico de Barredura y Difractometria de rayos X para determinar la efectividad de los tratamientos realizados. Fueron realizados ensayos mecánicos de tracción y flexión y los resultados mostraron un incremento de la resistencia a tracción media de 156% en relación al Poliéster puro y un 186 % de la resistencia a flexión.

Resumen En esta investigación el pigmento inorgánico con estructura espinela CoCr2O4 se sintetizó por el método de síntesis de combustión en solución usando glicina como combustible. Los polvos obtenidos después de la combustión y al final de una etapa de calcinación a 700°C por 6 h se caracterizaron por difracción de rayos X, lo cual mostró que la fase espinela se obtuvo después de la combustión y que es térmicamente estable hasta 700°C. Las imágenes de microscopia electrónica de barrido de emisión de campo mostraron la formación de una microestructua porosa con partículas de formas irregulares aglomeradas. Finalmente, se observaron los espectros de reflectancia difusa visible con una banda de absorción en el rango entre 570 y 670 nm, la cual es asociada a transiciones electrónicas permitidas por espín 4A2 (F)→ 4T1 (P) cuando el catión de Co2+ se encuentra en posiciones tetraédricas, también se encuentran bandas de absorción entre 400 nm y 440 nm, asociadas a las transiciones de electrones permitidas por espín 4A2g →4T2g en el catión Cr3+, cuando se encuentra en posiciones octaédricas. Las coordenadas de color CIEL*a*b*, mostraron una tonalidad verde, la cual coincide con los espectros de reflectancia difusa.

Abstract In this research, inorganic pigment with spinel structure CoCr2O4 was synthesized by the solution combustion synthesis using glycine as fuel in a one-step. The powders as-prepared after combustion and then calcined at 700°C during 6 hours, were characterized by the X-ray diffraction (XRD), and both samples showed the peaks corresponding to the expected spinel structure. Which showed that the spinel structure was obtained in the combustion reaction. Images of field emission scanning electron microscope (FE-SEM) showed the formation of porous and agglomeration of particles with, irregular shape. Finally, diffuse reflectance visible spectra were showed with an absorption band in the range of 570 nm -670 nm, which is due to electronic transitions corresponding to 4A2 (F)→4T1 (P) when the catión of Co2+ in tetrahedrical position and electronic transitions 4A2g →4T2g of Cr3+ in octaedrical positions. Color coordinates CIEL*a*b* correspond to a green color, which is consistent with the diffuse reflectance spectra.

The microwave-assisted hydrothermal method was used to obtain α-Ag2WO4. Rietveld refinement confirmed that α-Ag2WO4 is stable in the orthorhombic phase, without secondary phase. However, field-effect scanning electron microscope analysis showed that α-Ag2WO4 nanorods surfaces contain silver nanoparticles, confirmed by the X-ray photoelectron spectroscopy by the peak observed at 374.39 eV. In addition to metallic Ag, other Ag oxidation states were also observed on the surface. Hence, Ag (I) as Ag2O and Ag (I) as Ag2WO4 also were identified. DC measurements exhibited a high capacity of charge storage, nevertheless, with a large loss tangent (0.12 µC.cm-2.V-1) and no residual polarization for the voltage range between -100 V and +100 V. AC measurements at frequencies less than 275 Hz, revealed that ionic polarization is dominant, whereas at frequencies higher than 275 Hz, the electronic behavior predominates. The potential of electromagnetic energy conversion in thermal was observed from loss tangent analysis.

ABSTRACT For the goal of determining the mechanical and impact properties to nanocomposites of polypropylene with multiwall carbon nanotubes at 1, 3 and 5 %, morphologic studies using Scanning Electronic Microscope were accomplished, obtaining micrographics with a uniform dispersion of nanotubes in the polymeric matrix. Besides, by means of the technique of Mechanical Dynamic Analysis and essays Izod and traction, it was observed, in a general form, than to measure than increases the contents of nanotubes, the mechanical properties increase regarding the polymeric matrix, that demonstrate, the effect of reinforcement. On the other hand, the increase of the dynamic storage module, show an increment of stiffness. According to obtained results, it can be conclude that obtained nanocomposites are lighter and more resistant in front of collisions and impacts, which can be employ at different sectors of industry.

RESUMEN Con el objetivo de determinar las propiedades mecánicas y de impacto a nanocompuestos de polipropileno con nanotubos de carbono multipared al 1, 3 y 5 %, se le realizaron estudios morfológicos con el Microscópico Electrónico de Barrido, obteniendo micrografías con una dispersión uniforme de los nanotubos en la matriz polimérica. Además, mediante la técnica de Análisis Dinámico Mecánico y los ensayos Izod y de Tracción, se observó de manera general, que a medida que se aumenta el contenido de los nanotubos, las propiedades mecánicas se incrementan con respecto a la matriz polimérica, lo que demuestra el efecto de reforzamiento. Por otra parte, se ve reflejado el aumento del módulo de almacenamiento dinámico, indicando un incremento de la rigidez. De acuerdo con los resultados obtenidos, se concluye que los nanocompuestos obtenidos son más ligeros y resistentes frente a colisiones e impactos, los cuales pueden ser empleados en diferentes sectores de la industria.

Influence of solid solution temperature on microstructures and corrosion properties of CoNiCrMo alloy were investigated by means of optical microscopy (OM), scanning electron microscope (SEM) and electronic differential system. The corrosion resistance of CoNiCrMo alloy in 0.9%NaCl aqueous solution was also investigated. The results indicated that with the increase of solution treatment temperature, the dendrites of CoNiCrMo alloy gradually disappeared. Thus, the corrosion resistance of the alloy decreased. When the solution temperature is 1200ºC, the dendrites almost disappeared and most carbide dissolved, and begins to spheroidization. The corrosion resistance of CoNiCrMo alloy treated at 1000ºC for 1h is the highest than the one at 1100 ºC and 1200ºC. Its self-corrosion potential is -424mV and self-corrosion current density is 1.02×10-8A/cm2.

RESUMO O estudo sobre os materiais para obter fibras naturais tem tido grande importância nas últimas décadas devido às características excepcionais que essas fibras oferecem, as quais as convertem em uma alternativa interessante para substituir as fibras sintéticas em diferentes aplicações. O Bambu tem alta disponibilidade em várias regiões do mundo, devido à capacidade de adaptação e de crescimento em diferentes áreas. Apesar de as fibras de bambu estarem sendo altamente aplicadas, sua organização microestrutural dentro das hastes não tem sido estudada amplamente. O objetivo desta pesquisa está baseado no desenvolvimento e estudo das características e distribuição das fibras dentro do colmo no bambu nativo colombiano Guadua angustifolia Kunth. Neste estudo foram consideradas duas variedades de Guadua: Guadua angustifolia Kunth Rayada Amarilla e Guadua angustifolia Kunth Macana. As Guaduas foram analisadas por microscopia eletrônica de varredura, esta técnica é usada para observar a morfologia da fibra de Guadua e a sua variação através do colmo. Difração de raios X é usada para observar variação dos compostos através do colmo. Finalmente, a metodologia da “Association Official Agricultural Chemist - 2000” (AOAC-2000) é usada para obter informação quantitativa do conteúdo de fibra não solúvel. Os resultados indicaram que a distribuição de fibras não solúveis não é homogênea entre as camadas internas e externas da haste do bambu, isso aumenta na direção radial da parede interna até a parede externa; os padrões de difração de raios X mostram que a celulose presente no colmo tem uma preferência de ligação cristalina relacionada à direção do crescimento da planta. A combinação da análise de microscopia eletrônica de varredura e a difração de raios X oferecem informações importantes sobre a distribuição e a morfologia dentro do colmo dos componentes do Bambu.

ABSTRACT Studies about lignocellulosic materials have gained importance in the last decades due to the outstanding characteristics that their fibers offer, which becomes in a good alternative to replace synthetic fibers. Lignocellulosic materials such as bamboo have high availability in most of regions around the world due to the adaptation capacity to grow in different areas and diverse climatic conditions. Despite of this fiber has being widely used; their microstructural organization into the culm has not been fully studied. The focus of this research is to study the morphology, distribution and crystalline compounds of fiber in native Colombian Bamboo called Guadua angustifolia Kunth for two varieties Rayada Amarilla and Macana. Scanning electron microscopy was used to observe Guadua fiber morphology and their variation throughout the culm, X-ray diffraction was used to identify crystalline compounds present in Guadua angustifolia Kunth and AOAC-2000 methodology (Association Official Agricultural Chemist) was used to get quantitative information about the insoluble and soluble fiber content into Guadua culm. Findings indicated that the insoluble fiber distribution is not homogenous between the internal and external layer of bamboo culm; the fiber content inside of Guadua angustifolia culms increases from inner to outer layer. X-ray patterns showed that the insoluble fiber has a preferential crystalline orientation in relation to the growth direction of bamboo. The combination of scanning electronic microscope and X-ray diffraction offers important information about the localization and morphologic distribution of components inside bamboo culms.

RESUMEN Para estudiar las formaciones que aparecen tras las reacciones de fraguado en los morteros fabricados utilizando polvo de vidrio como ligante, se han analizado mediante difracción por rayos X y espectrometría de energía dispersiva (EDS) con Microscopio Electrónico de Barrido (MEB) acoplado, morteros y pastas con diferentes composiciones. Dichos análisis han mostrado la aparición de unas formaciones similares a los geles C-S-H, en las que la relación Ca/Si es menor que para los C-S-H que aparecen con ligante convencionales. Además, se ha observado que la forma de los geles es ligeramente diferente cuando las muestras se conservan en agua. Estas formaciones, más filamentosas, y la presencia de mayor número de moléculas de Si hace que las reacciones de fraguado se mantengan durante más tiempo, y proporcionen una cierta capacidad de autoregeneración sin intervención externa, esto hace que su uso sea idóneo en la estabilización de suelos.

ABSTRACT Mortar and paste with different composition were analyzed with X-ray diffraction and dispersive energy spectrometry (EDS) with coupled Electronic Scanning Microscope (SEM) to study the formation that appear after the setting reaction in the mortar made by using glass powder, with a size of 16μ, as binder. Such analysis shows the occurrence of formations similar to C-S-H gels, but in which, the Ca/Si ratio is lower than for typical C-S-H gels. In addition it was observed that the shape of the gels is slightly different when the samples are preserved in water. These more filamentous formations and the presence of a larger number of Si molecules causes the setting reaction to be maintained for a longer period of time and provide a certain capacity for self-regeneration without external intervention, which makes it suitable for soil stabilization.