598 resultados para RIGIDITY


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Cardiovascular diseases (CVDs) have reached an epidemic proportion in the US and worldwide with serious consequences in terms of human suffering and economic impact. More than one third of American adults are suffering from CVDs. The total direct and indirect costs of CVDs are more than $500 billion per year. Therefore, there is an urgent need to develop noninvasive diagnostics methods, to design minimally invasive assist devices, and to develop economical and easy-to-use monitoring systems for cardiovascular diseases. In order to achieve these goals, it is necessary to gain a better understanding of the subsystems that constitute the cardiovascular system. The aorta is one of these subsystems whose role in cardiovascular functioning has been underestimated. Traditionally, the aorta and its branches have been viewed as resistive conduits connected to an active pump (left ventricle of the heart). However, this perception fails to explain many observed physiological results. My goal in this thesis is to demonstrate the subtle but important role of the aorta as a system, with focus on the wave dynamics in the aorta.

The operation of a healthy heart is based on an optimized balance between its pumping characteristics and the hemodynamics of the aorta and vascular branches. The delicate balance between the aorta and heart can be impaired due to aging, smoking, or disease. The heart generates pulsatile flow that produces pressure and flow waves as it enters into the compliant aorta. These aortic waves propagate and reflect from reflection sites (bifurcations and tapering). They can act constructively and assist the blood circulation. However, they may act destructively, promoting diseases or initiating sudden cardiac death. These waves also carry information about the diseases of the heart, vascular disease, and coupling of heart and aorta. In order to elucidate the role of the aorta as a dynamic system, the interplay between the dominant wave dynamic parameters is investigated in this study. These parameters are heart rate, aortic compliance (wave speed), and locations of reflection sites. Both computational and experimental approaches have been used in this research. In some cases, the results are further explained using theoretical models.

The main findings of this study are as follows: (i) developing a physiologically realistic outflow boundary condition for blood flow modeling in a compliant vasculature; (ii) demonstrating that pulse pressure as a single index cannot predict the true level of pulsatile workload on the left ventricle; (iii) proving that there is an optimum heart rate in which the pulsatile workload of the heart is minimized and that the optimum heart rate shifts to a higher value as aortic rigidity increases; (iv) introducing a simple bio-inspired device for correction and optimization of aortic wave reflection that reduces the workload on the heart; (v) deriving a non-dimensional number that can predict the optimum wave dynamic state in a mammalian cardiovascular system; (vi) demonstrating that waves can create a pumping effect in the aorta; (vii) introducing a system parameter and a new medical index, Intrinsic Frequency, that can be used for noninvasive diagnosis of heart and vascular diseases; and (viii) proposing a new medical hypothesis for sudden cardiac death in young athletes.

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When a structure vibrates immersed in a fluid it is known that the dynamic properties of the system are modified. The surrounding fluid will, in general, contribute to the inertia, the rigidity and the damping coefficient of the coupled fluid-structure system. For light structures, like spacecraft antennas, even when the fluid is air the contribution to the dynamic properties can be important. For not so light structures the ratio of the equivalent fluid/structure mass and rigidity can be very small and the fluid contribution could be neglected. For the ratio of equivalent fluid/structure damping both terms are of the same order and therefore the fluid contribution must be studied. The working life of the spacecraft structure would be on space and so without any surrounding fluid. The response of a spacecraft structure on its operational life would be attenuated by the structural damping alone but when the structure is dynamically tested on the earth the dynamic modal test is performed with the fluid surrounding it. The results thus are contaminated by the effects of the fluid. If the damping added by the fluid is of the same order as the structural damping the response of the structure in space can be quite different to the response predicted on earth. It is therefore desirable to have a method able to determine the amount of damping induced by the fluid and that should be subtracted of the total damping measured on the modal vibration test. In this work, a method for the determination of the effect of the surrounding fluid on the dynamic characteristics of a circular plate has been developed. The plate is assumed to vibrate harmonically with the vacuum modes and the generalized forces matrix due to the fluid is thus computed. For a compressible fluid this matrix is formed by complex numbers including terms of inertia, rigidity and damping. The matrix due to the fluid loading is determined by a boundary element method (BEM). The BEM used is of circular rings on the plate surface so the number of elements to obtain an accurate result is very low. The natural frequencies of the system are computed by an iteration procedure one by one and also the damping fluid contribution. Comparisons of the present method with various experimental data and other theories show the efficiency and accuracy of the method for any support condition of the plate.

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In a principal-agent model we analyze the firm’s decision to adopt an informal or a standardized Environmental Management System (EMS). Our results are consistent with empirical evidence in several respects. A standardized EMS increases the internal control at the cost of introducing some degree of rigidity that entails an endogenous setup cost. Standardized systems are more prone to be adopted by big and well established firms and under tougher environmental policies. Firms with standardized EMS tend to devote more effort to abatement although this effort results in lower pollution only if public incentives are strong enough, suggesting a complementarity relationship between standardized EMS and public policies. Emission charges have both a marginal effect on abatement and a qualitative effect on the adoption decision that may induce a conflict between private and public interests. As a result of the combination of these two effects it can be optimal for the government to distort the tax in a specific way in order to push the firm to choose the socially optimal EMS. The introduction of standardized systems can result in win-win situations where firms, society and the environment get better off.

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New nanocomposites based on polyethylene have been prepared by in situ polymerization of ethylene in presence of mesoporous MCM-41. The polymerization reactions were performed using a zirconocene catalyst either under homogenous conditions or supported onto mesoporous MCM-41 particles, which are synthesized and decorated post-synthesis with two silanes before polymerization in order to promote an enhanced interfacial adhesion. The existence of polyethylene chains able to crystallize within the mesoporous channels in the resulting nanocomposites is figured out from the small endothermic process, located at around 80 C, on heating calorimetric experiments, in addition to the main melting endotherm. These results indicate that polyethylene macrochains can grow up during polymerization either outside or inside the MCM-41 channels, these keeping their regular hexagonal arrangements. Mechanical response is observed to be dependent on the content in mesoporous MCM-41 and on the crystalline features of polyethylene. Accordingly, stiffness increases and deformability decreases in the nanocomposites as much as MCM-41 content is enlarged and polyethylene amount within channels is raised. Ultimate mechanical performance improves with MCM-41 incorporation without varying the final processing temperature.

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Dissertação de Mestrado para obtenção do grau de Mestre em Design de Comunicação, apresentada na Universidade de Lisboa - Faculdade de Arquitectura

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The employment of flexibility in the design of façades makes them adaptable to adverse weather conditions, resulting in both minimization of environmental discomfort and improvement of energy efficiency. The present study highlights the potential of flexible façades as a resource to reduce rigidity and form repetition, which are usually employed in condominiums of standardized houses; as such, the work presented herein contributes to field of study of architectural projects strategies for adapting and integrating buildings within the local climate context. Two façade options were designed using as reference the bionics and the kinetics, as well as their applications to architectural constructions. This resulted in two lightweight and dynamic structures, which cater to constraints of comfort through combinations of movements, which control the impact of solar radiation and of cooling in the environment. The efficacy and technical functionality of the façades were tested with comfort analysis and graphic computation software, as well as with physical models. Thus, the current research contributes to the improvement of architectural solutions aimed at using passive energy strategies in order to offer both better quality for the users and for the sustainability of the planet

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As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy

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Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciência Política, Programa de Pós-Graduação em Ciência Política, 2016.

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Le graphène est une nanostructure de carbone hybridé sp2 dont les propriétés électroniques et optiques en font un matériau novateur avec un très large potentiel d’application. Cependant, la production à large échelle de ce matériau reste encore un défi et de nombreuses propriétés physiques et chimiques doivent être étudiées plus en profondeur pour mieux les exploiter. La fonctionnalisation covalente est une réaction chimique qui a un impact important dans l’étude de ces propriétés, car celle-ci a pour conséquence une perte de la structure cristalline des carbones sp2. Néanmoins, la réaction a été très peu explorée pour ce qui est du graphène déposé sur des surfaces, car la réactivité chimique de ce dernier est grandement dépendante de l’environnement chimique. Il est donc important d’étudier la fonctionnalisation de ce type de graphène pour bien comprendre à la fois la réactivité chimique et la modification des propriétés électroniques et optiques pour pouvoir exploiter les retombées. D’un autre côté, les bicouches de graphène sont connues pour avoir des propriétés très différentes comparées à la monocouche à cause d’un empilement des structures électroniques, mais la croissance contrôlée de ceux-ci est encore très difficile, car la cinétique de croissance n’est pas encore maîtrisée. Ainsi, ce mémoire de maîtrise va porter sur l’étude de la réactivité chimique du graphène à la fonctionnalisation covalente et de l’étude des propriétés optiques du graphène. Dans un premier temps, nous avons effectué des croissances de graphène en utilisant la technique de dépôt chimique en phase vapeur. Après avoir réussi à obtenir du graphène monocouche, nous faisons varier les paramètres de croissance et nous nous rendons compte que les bicouches apparaissent lorsque le gaz carboné nécessaire à la croissance reste présent durant l’étape de refroidissement. À partir de cette observation, nous proposons un modèle cinétique de croissance des bicouches. Ensuite, nous effectuons une étude approfondie de la fonctionnalisation du graphène monocouche et bicouche. Tout d’abord, nous démontrons qu’il y a une interaction avec le substrat qui inhibe grandement le greffage covalent sur la surface du graphène. Cet effet peut cependant être contré de plusieurs façons différentes : 1) en dopant chimiquement le graphène avec des molécules réductrices, il est possible de modifier le potentiel électrochimique afin de favoriser la réaction; 2) en utilisant un substrat affectant peu les propriétés électroniques du graphène; 3) en utilisant la méthode d’électrogreffage avec une cellule électrochimique, car elle permet une modulation contrôlée du potentiel électrochimique du graphène. De plus, nous nous rendons compte que la réactivité chimique des bicouches est moindre dû à la rigidité de structure due à l’interaction entre les couches. En dernier lieu, nous démontrons la pertinence de la spectroscopie infrarouge pour étudier l’effet de la fonctionnalisation et l’effet des bicouches sur les propriétés optiques du graphène. Nous réussissons à observer des bandes du graphène bicouche dans la région du moyen infrarouge qui dépendent du dopage. Normalement interdites selon les règles de sélection pour la monocouche, ces bandes apparaissent néanmoins lorsque fonctionnalisée et changent grandement en amplitude dépendamment des niveaux de dopage et de fonctionnalisation.

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Intracochlear trauma from surgical insertion of bulky electrode arrays and inadequate pitch perception are areas of concern with current hand-assembled commercial cochlear implants. Parylene thin-film arrays with higher electrode densities and lower profiles are a potential solution, but lack rigidity and hence depend on manually fabricated permanently attached polyethylene terephthalate (PET) tubing based bulky backing devices. As a solution, we investigated a new backing device with two sub-systems. The first sub-system is a thin poly(lactic acid) (PLA) stiffener that will be embedded in the parylene array. The second sub-system is an attaching and detaching mechanism, utilizing a poly(N-vinylpyrrolidone)-block-poly(d,l-lactide) (PVP-b-PDLLA) copolymer-based biodegradable and water soluble adhesive, that will help to retract the PET insertion tool after implantation. As a proof-of-concept of sub-system one, a microfabrication process for patterning PLA stiffeners embedded in parylene has been developed. Conventional hotembossing, mechanical micromachining, and standard cleanroom processes were integrated for patterning fully released and discrete stiffeners coated with parylene. The released embedded stiffeners were thermoformed to demonstrate that imparting perimodiolar shapes to stiffener-embedded arrays will be possible. The developed process when integrated with the array fabrication process will allow fabrication of stiffener-embedded arrays in a single process. As a proof-of-concept of sub-system two, the feasibility of the attaching and detaching mechanism was demonstrated by adhering 1x and 1.5x scale PET tube-based insertion tools and PLA stiffeners embedded in parylene using the copolymer adhesive. The attached devices survived qualitative adhesion tests, thermoforming, and flexing. The viability of the detaching mechanism was tested by aging the assemblies in-vitro in phosphate buffer solution. The average detachment times, 2.6 minutes and 10 minutes for 1x and 1.5x scale devices respectively, were found to be clinically relevant with respect to the reported array insertion times during surgical implantation. Eventually, the stiffener-embedded arrays would not need to be permanently attached to current insertion tools which are left behind after implantation and congest the cochlear scala tympani chamber. Finally, a simulation-based approach for accelerated failure analysis of PLA stiffeners and characterization of PVP-b-PDLLA copolymer adhesive has been explored. The residual functional life of embedded PLA stiffeners exposed to body-fluid and thereby subjected to degradation and erosion has been estimated by simulating PLA stiffeners with different parylene coating failure types and different PLA types for a given parylene coating failure type. For characterizing the PVP-b-PDLLA copolymer adhesive, several formulations of the copolymer adhesive were simulated and compared based on the insertion tool detachment times that were predicted from the dissolution, degradation, and erosion behavior of the simulated adhesive formulations. Results indicate that the simulation-based approaches could be used to reduce the total number of time consuming and expensive in-vitro tests that must be conducted.

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Conjugated polymers (CPs) are intrinsically fluorescent materials that have been used for various biological applications including imaging, sensing, and delivery of biologically active substances. The synthetic control over flexibility and biodegradability of these materials aids the understanding of the structure-function relationships among the photophysical properties, the self-assembly behaviors of the corresponding conjugated polymer nanoparticles (CPNs), and the cellular behaviors of CPNs, such as toxicity, cellular uptake mechanisms, and sub-cellular localization patterns. ^ Synthetic approaches towards two classes of flexible CPs with well-preserved fluorescent properties are described. The synthesis of flexible poly( p-phenylenebutadiynylene)s (PPBs) uses competing Sonogashira and Glaser coupling reactions and the differences in monomer reactivity to incorporate a small amount (∼10%) of flexible, non-conjugated linkers into the backbone. The reaction conditions provide limited control over the proportion of flexible monomer incorporation. Improved synthetic control was achieved in a series of flexible poly(p-phenyleneethynylene)s (PPEs) using modified Sonogashira conditions. In addition to controlling the degree of flexibility, the linker provides disruption of backbone conjugation that offers control of the length of conjugated segments within the polymer chain. Therefore, such control also results in the modulation of the photophysical properties of the materials. ^ CPNs fabricated from flexible PPBs are non-toxic to cells, and exhibit subcellular localization patterns clearly different from those observed with non-flexible PPE CPNs. The subcellular localization patterns of the flexible PPEs have not yet been determined, due to the toxicity of the materials, most likely related to the side-chain structure used in this series. ^ The study of the effect of CP flexibility on self-assembly reorganization upon polyanion complexation is presented. Owing to its high rigidity and hydrophobicity, the PPB backbone undergoes reorganization more readily than PPE. The effects are enhanced in the presence of the flexible linker, which enables more efficient π-π stacking of the aromatic backbone segments. Flexibility has minimal effects on the self-assembly of PPEs. Understanding the role of flexibility on the biophysical behaviors of CPNs is key to the successful development of novel efficient fluorescent therapeutic delivery vehicles.^

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Le graphène est une nanostructure de carbone hybridé sp2 dont les propriétés électroniques et optiques en font un matériau novateur avec un très large potentiel d’application. Cependant, la production à large échelle de ce matériau reste encore un défi et de nombreuses propriétés physiques et chimiques doivent être étudiées plus en profondeur pour mieux les exploiter. La fonctionnalisation covalente est une réaction chimique qui a un impact important dans l’étude de ces propriétés, car celle-ci a pour conséquence une perte de la structure cristalline des carbones sp2. Néanmoins, la réaction a été très peu explorée pour ce qui est du graphène déposé sur des surfaces, car la réactivité chimique de ce dernier est grandement dépendante de l’environnement chimique. Il est donc important d’étudier la fonctionnalisation de ce type de graphène pour bien comprendre à la fois la réactivité chimique et la modification des propriétés électroniques et optiques pour pouvoir exploiter les retombées. D’un autre côté, les bicouches de graphène sont connues pour avoir des propriétés très différentes comparées à la monocouche à cause d’un empilement des structures électroniques, mais la croissance contrôlée de ceux-ci est encore très difficile, car la cinétique de croissance n’est pas encore maîtrisée. Ainsi, ce mémoire de maîtrise va porter sur l’étude de la réactivité chimique du graphène à la fonctionnalisation covalente et de l’étude des propriétés optiques du graphène. Dans un premier temps, nous avons effectué des croissances de graphène en utilisant la technique de dépôt chimique en phase vapeur. Après avoir réussi à obtenir du graphène monocouche, nous faisons varier les paramètres de croissance et nous nous rendons compte que les bicouches apparaissent lorsque le gaz carboné nécessaire à la croissance reste présent durant l’étape de refroidissement. À partir de cette observation, nous proposons un modèle cinétique de croissance des bicouches. Ensuite, nous effectuons une étude approfondie de la fonctionnalisation du graphène monocouche et bicouche. Tout d’abord, nous démontrons qu’il y a une interaction avec le substrat qui inhibe grandement le greffage covalent sur la surface du graphène. Cet effet peut cependant être contré de plusieurs façons différentes : 1) en dopant chimiquement le graphène avec des molécules réductrices, il est possible de modifier le potentiel électrochimique afin de favoriser la réaction; 2) en utilisant un substrat affectant peu les propriétés électroniques du graphène; 3) en utilisant la méthode d’électrogreffage avec une cellule électrochimique, car elle permet une modulation contrôlée du potentiel électrochimique du graphène. De plus, nous nous rendons compte que la réactivité chimique des bicouches est moindre dû à la rigidité de structure due à l’interaction entre les couches. En dernier lieu, nous démontrons la pertinence de la spectroscopie infrarouge pour étudier l’effet de la fonctionnalisation et l’effet des bicouches sur les propriétés optiques du graphène. Nous réussissons à observer des bandes du graphène bicouche dans la région du moyen infrarouge qui dépendent du dopage. Normalement interdites selon les règles de sélection pour la monocouche, ces bandes apparaissent néanmoins lorsque fonctionnalisée et changent grandement en amplitude dépendamment des niveaux de dopage et de fonctionnalisation.

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The study of textiles is an open area of scientific research, which for its variety of material components and physical chemical diversity of conditions, makes a field of interest for scientific studies in the cultural heritage field. Archaeological/historical textiles offer the possibility to carry out studies on organic materials such as fibers, adhesion elements, dyes, paper, etc., as well as on inorganic compounds for instance metals, alloys, precious stones and other added ornamentation. That variety of composition, allow to use a combination of analytical techniques to solve the questions coming from the object in an archaeometric research. One kind of textile object that provides a valuable cultural information because of its linguistic representation employed by its carrier societies, are the flags/banners/emblems, objects made with a nonverbal communication purpose. As long as depending on the use and/or purpose of each object, varies both the materials/techniques used in its production and its iconography (style, color, emblem, shape), its study gives the possibility to extract information through their materials and manufacturing techniques about a temporal-spatial frame, a particular event or a specific character. The flags/banners have been used since the eleventh century as representative objects of power, hierarchy, social or military organization, or as communicative media. The use of these objects has been spread throughout the world, possibly due to its easy interpretation and/or appropriation by different societies, making it part of their own culture. The flags as symbols of territorial control, using emblems that represent a family, order or army, were introduced to the New World (America) with the arrival of the European conquerors at the end of the fifteenth century. Flags/banners representing the Royal dominion over conquered territories, the Catholic Church and conquistadors’ armies were the first to arrive. One of those flags that have endured over time, that have an invaluable cultural meaning for both American and Iberian societies, is the so-called Francisco Pizarro’s Banner of Arms. It is a textile object with metal threads decoration over a Royal emblem. According to historical sources, this object was used by Francisco Pizarro in 1532 on the conquest process of Peru, after received the permission by King Charles V to on behalf of him, to conquer the lands of the New World today known as Peru. After Pizarro’s control of the Inca territory, it is believed that Pizarro left his banner on top of the Inca’s Sun’s Temple as symbol of his rule. Centuries later, in the America libertarian campaigns, General Sucre, military at charge of the independence army in Peru, reports have found what he considered the Pizarro’s Banner, sending it to Bogotá as a symbol of victory, being kept since that time until today by the National Museum of Colombia. Due to historical discrepancies in the different movements of the so-called Pizarro’s Banner of Arms, its real meaning has been under discussion and because of the passage of time its physical condition has suffer deterioration. That is because its scientific study is now an interesting case study to respond to both historical and conservation questions of it. Through a collaboration with the National Museum of Colombia, a set of 25 samples of so-called Pizarro’s Banner of Arms were collected, covering the various components and areas from the object of study. These samples were subjected to analytical studies for physical and chemical characterization. Microscopic observation, VSEM-EDS analysis, Raman spectroscopy, chromatographic analysis (HPLC-MS, GCMS) and radiocarbon dating were done. Similarly, was sought through a direct in situ physical inspection to the object and through a research into historical sources, adequate information to solve the object’s problems. Results obtained allowed to identify as silk the textile used in the elaboration of the Banner’s fabric, as well as the use of natural dyes for dyeing the fibers used on the emblem: use of cochineal and brazil wood as a source of red, luteolin plant-based for yellow color, indigotine plant-based for blue, and a mixture of yellow and blue dyes for green were identified. Similarly, the use of animal glue in the manufacturing process and the use of rag paper was evident. The metal threads study from the Banner give a confirmation to a silver core wire gilded with a thin gold sheet, being flattened and entwined with silk threads for their use. Finally, using the radiocarbon results, it was possible to postulate with huge accuracy that the Banner date manufacture was between the XV-XVI century and subject to restoration processes with addition of textiles in modern times. Together with, was evident that the state of degradation of the fabric is due to natural degradation in the silk fibers, having that its color has faded and its mechanical properties decreased, leading to loss of rigidity and disappearance of the physical structure. Similarly, it was clear the original colors of the emblem and highlight problems of detachment of paper due to crystallization of the adhesive. In the same way, was found that the metal threads suffer corrosion by sulfur and detachment of its crystals. Finally, combining the analytical results and the historical sources data found from the so-called Francisco Pizarro’s Banner of Arms, allows to postulate that its manufacture process was done in Europe employing precious materials to obtain a long-life object with a deep message for its viewers. Also, the data obtained helps to support the possible idea that the object was employed by Francisco Pizarro in the Peru conquest process. However, by the symbols present in the object, its elaboration date and materials, this object its clearly unique in its kind, and the most important, by its linguistic message, does not represent to Francisco Pizarro or his army, meanwhile, represents the Spanish crown. Therefore, instead to be labeled as Francisco Pizarro’s Banner of Arms, it should be called the Colonial Royal Banner of Charles V in the New World; RESUMEN: El estudio de textiles es un área abierta de investigación científica, la cual por su variedad de componentes materiales y la diversidad de condiciones físico-químicas presentes en estos objetos, lo hace un campo de interés para estudios científicos en el patrimonio cultural. Los textiles arqueológicos/históricos brindan la posibilidad de realizar estudios en materiales orgánicos como fibras, elementos de adhesión, tinturas, papel, etc., e inorgánicos como metales, aleaciones, piedras preciosas y demás materiales decorativos añadidos. Por su variedad de composición, es posible emplear diversas técnicas analíticas para resolver aquellas preguntas propias del objeto en una investigación arqueométrica. Uno de los objetos textiles que brinda gran información cultural debido a su representación lingüística empleada por las sociedades portadoras, son las banderas/estandartes/emblemas. Donde varía dependiendo de su uso y/o propósito, los materiales empleados en su elaboración, al igual que su iconografía (estilo, color, emblema, forma). El estudio de estos objetos construidos con un propósito de comunicación no verbal, da la posibilidad de extraer información a través de sus materiales y técnicas de elaboración sobre un rango temporal-espacial, un evento determinado en la historia o incluso a un personaje en específico. Las banderas han sido empleadas desde el siglo XI como objetos representativos de poder, jerarquía, organización social o militar, o como medio de comunicación. El uso de estos objetos se ha extendido a lo largo del mundo posiblemente debido a su fácil interpretación y/o apropiación por distintas sociedades, haciéndolo parte de su cultura. Las banderas como símbolos de control territorial, empleando símbolos que representan a una familia, orden o armada fueron introducidas a el Nuevo Mundo (América) con la llegada de los conquistadores europeos al final del siglo XV. Las banderas/estandartes que representaban el dominio Real sobre territorios dominados, la iglesia católica y las banderas de ejércitos y/o conquistadores fueron las primeras en llegar al nuevo mundo. Una de aquellas banderas que ha soportado el paso del tiempo, teniendo un gran valor cultural tanto para las sociedades americanas como para las ibéricas, es el denominado Estandarte de armas de Francisco Pizarro. Siendo un objeto textil con decoración en hilos metálicos sobre un emblema Real. De acuerdo a fuentes históricas, este objeto fue usado por Francisco Pizarro en 1532 en el proceso de conquista del Perú, quien recibe por parte del Rey Carlos V el poder para que, en su nombre, Pizarro pueda conquistar las tierras del nuevo mundo hoy conocidas como Perú. Luego del dominio de Pizarro sobre el territorio Inca, se cree que Pizarro dejó su estandarte en la cima del templo Inca del sol como símbolo de su control. Siglos más tarde, en las campañas libertarias de América, el General Sucre, militar encargado de la armada independentista en Perú, reporta haber encontrado lo que él considera como el estandarte de Pizarro, enviándolo a Bogotá como muestra de victoria, siendo custodiada desde ese momento por el Museo Nacional de Colombia hasta la actualidad. Debido a discrepancias históricas, el verdadero significado del llamado estandarte de Pizarro ha sido objeto de discusión y debido del pasar del tiempo su estado de conservación se ha deteriorado. Dejando de este modo, un caso de estudio interesante para que por medio de estudios científicos al objeto se pueda dar respuesta a preguntas tanto históricas como de conservación del mismo. De este modo, por medio de una colaboración con el Museo Nacional de Colombia, se obtuvo un juego de 25 muestras del llamado Estandarte de armas de Francisco Pizarro, abarcando los diferentes componentes y áreas del objeto de estudio. Dichas muestras fueron sometidas a estudios analíticos para su caracterización físico-química. Análisis de observación al microscopio, análisis VSEM-EDS, espectroscopia Raman, análisis cromatográficos (HPLC-MS, GC-MS) y datación por radiocarbono catorce fueron realizados. Del mismo modo, por medio de una inspección física al objeto in situ y una profunda investigación en fuentes históricas del mismo, se buscó la información adecuada para resolver sus problemáticas. Los resultados obtenidos permitieron identificar como seda el textil empleado en la elaboración del estandarte, así como el uso de colorantes naturales para teñir las fibras en el emblema: uso de cochinilla y palo de Brasil como fuente del color rojo, plantas a base de luteolin para el color amarillo, plantas a base de indigotina para el color azul y mezcla de colorantes amarillos y azules para el color verde fueron identificadas. Del mismo modo se evidencio el uso de adhesivos animales y el uso de papel de trapos en el proceso de manufactura. El estudio de los hilos metálicos, permitió evidenciar el uso de alambres con núcleos de plata con un fino recubrimiento de oro en su exterior, siendo aplanados y entrelazados con hilos de seda para su uso. Finalmente usando la datación por radiocarbono, fue posible conocer con alta precisión que el estandarte fue elaborado entre los siglos XV-XVI y sufrió procesos de restauración con añadidura de textiles en tiempos modernos. Junto a lo anterior, es posible postular que el estado de degradación de la tela es debido a degradación natural en las fibras de seda, teniendo así que su color se ha desvanecido y sus propiedades mecánicas disminuidas, conllevando a perdida de rigidez y desaparición de la estructura. Del mismo modo se pudo conocer los colores originales del emblema y evidenciar problemas de desprendimiento del papel debido a cristalización del adhesivo. Asimismo, se comprobó que los hilos metálicos presentan corrosión por azufre y desprendimiento de sus cristales. Finalmente, combinando los resultados analíticos y la información de fuentes históricas encontradas del llamado Estandarte de armas de Francisco Pizarro, se puede postular que su elaboración fue realizada en Europa, usando materiales preciosos para obtener un objeto de larga vida con un profundo mensaje para sus observadores. También, los datos obtenidos ayudan a dar soporte la posible idea de que este objeto fue usado por Francisco Pizarro en el proceso de conquista del Perú. Sin embargo, debido a los símbolos presentes en el objeto, fecha y materiales de elaboración, este objeto es claramente único en su tipo, y lo más importante, por su mensaje lingüístico, este no representa a Francisco Pizarro o su armada, al contrario, representa a la Corona de España. Por ende, en vez de denominarse como Estandarte de armas de Francisco Pizarro, este objeto debería nombrarse como el Estandarte Real de la Colonia de Carlos V en el Nuevo Mundo.