Mechanical, electrical and sensing properties of melt-spun polymer fibers filled with carbon nanoparticles

Multifunctional polymer fibers with strain and liquid sensing capabilities were fabricated and characterized. The Hansen Solubility Parameters (HSPs) were used as a tool for selecting a suitable polymer to employ as matrix for the sensing material before fiber fabrication. The addition of conductive carbon particles to a polymer matrix provides it with sensing capabilities, such as against tensile strain and the presence of liquids as it was evaluated in this work. Multiwall carbon nanotubes (MWCNTs, MW) as well as a mixture of carbon black (CB) and MWCNTs in weight concentration of 1:1 were used as conductive fillers. The route followed to achieve electrically conductive polymer fibers necessary for sensing evaluations was a combined process of melt-mixing and subsequent melt-spinning. Melt-mixing and melt-spinning are processing techniques widely used in the polymer industry that could enable the up-scaling of the fibers developed in this work. Additionally to single component fibers, bi-component (BICO) fibers consisting of a polycarbonate (PC)+CB+MW sheath and a neat PC core were also fabricated, characterized and their performance was compared to the single component fibers. The state of dispersion of the carbon nanoparticles (CNPs) as well as tensile behavior, electrical resistivity, strain and liquid sensing properties of the composite fibers were evaluated. Finally a specific fiber composition with potential to be used as sensing material for mechanical strain and liquid exposition was proposed to be tested under two real situations (strain monitoring of a rigid structure and leakage detection of a chemical substance). Sensing fibers as the developed in this work have many potential applications such as real-time deformation and structural health monitoring and early cracking detection of any kind of structure. On the other hand, fibers able to sense the presence of liquids can perceive the leakage of chemicals that are hazardous to life. Moreover, this technology can also be applied in smart clothing manufacture by combining sensing fibers with flexible woven electronics

Solvent-antisolvent interactions in metal halide perovskites

The fabrication of metal halide perovskite films using the solvent-engineering method is increasingly common. In this method, the crystallisation of the perovskite layer is triggered by the application of an antisolvent during the spin-coating of a perovskite precursor solution. Herein, we introduce the current state of understanding of the processes involved in the crystallisation of perovskite layers formed by solvent engineering, focusing in particular on the role of antisolvent properties and solvent-antisolvent interactions. By considering the impact of the Hansen solubility parameters, we propose guidelines for selecting the appropriate antisolvent and outline open questions and future research directions for the fabrication of perovskite films by this method

Desarrollo de habilidades de pensamiento científico: una estrategia didáctica para niños de la zona altos de Cazucá con el propósito de aproximarlos a la noción de temperatura

This work evolves from our intervention at the institution “Corporación Social Fé y Esperanza” at Bogota, Colombia. This work has been an opportunity to reflect on the harsh context the children has to endure due to their condition of being displaced from their home land. We aim to put forward a didactical strategy to improve the development of scientific thinking’s skills by approaching them to de concept of temperature. In this strategy we set up contexts in which the students develop their ability to make question, to observe events, to realize description and to explain some natural phenomena of their environment. It is an option to see an design new ways to present science to children belonging to this contexts, by stimulating their taste to inquire and research on what happen in their surroundings, as well.La presente propuesta investigativa nace del trabajo de campo realizado en la Corporación Social Fe y Esperanza ubicada en Cazucá en el Barrio el Progreso. Esta propuesta ha permitido emprender una reflexión sobre la difícil situación que viven los niños por causa deldesplazamiento y las condiciones de pobreza de su entorno. La intención es llevar a esteescenario educativo una estrategia didáctica que favorezca el desarrollo de habilidades de pensamiento científico aproximándolos a la noción de temperatura. La propuesta investigativa favorece la recreación de espacios donde los niños desarrollen la capacidad de hacer preguntas, observar eventos, realizar descripciones sencillas y explicar algunos fenómenos naturales de su entorno; así mismo, es una opción para visualizar y diseñar nuevas alternativas para llevar la ciencia a los niños de estos contextos, estimulando su gusto por curiosear e indagar sobre lo que a su alrededor ocurre, explotando al máximo los espacios que para su estimulación ofrece el lugar donde habitan

Piezoresistive Strain Sensors Made from Carbon Nanotubes Based Polymer Nanocomposites

In recent years, nanocomposites based on various nano-scale carbon fillers, such as carbon nanotubes (CNTs), are increasingly being thought of as a realistic alternative to conventional smart materials, largely due to their superior electrical properties. Great interest has been generated in building highly sensitive strain sensors with these new nanocomposites. This article reviews the recent significant developments in the field of highly sensitive strain sensors made from CNT/polymer nanocomposites. We focus on the following two topics: electrical conductivity and piezoresistivity of CNT/polymer nanocomposites, and the relationship between them by considering the internal conductive network formed by CNTs, tunneling effect, aspect ratio and piezoresistivity of CNTs themselves, etc. Many recent experimental, theoretical and numerical studies in this field are described in detail to uncover the working mechanisms of this new type of strain sensors and to demonstrate some possible key factors for improving the sensor sensitivity

Cuerpos anfibios, soma y sema del cuerpo prehispánico, la otra medida del cuerpo a través del tiempo y el espacio: análisis bioarqueológico sobre las urnas funerarias en cerámica de los valles alto y medio –bajo del Río Magdalena. Colombia

Las sociedades prehispánicas tardías que habitaron las vertientes del Alto-medio y medio-bajo Río Magdalena hasta los albores de la invasión europea (Siglo XVI), tuvieron una percepción de la corporalidad humana, vinculada a los objetos y a los artefactos. Cuerpo y artefactos funcionaron más o menos de la misma forma, pues fueron tratados por los prehispánicos como un recipiente: contendor, contenido y continente. La descripción plástica de los cuerpos modelados en arcilla sobre el casquete de las urnas funerarias del Rio Magdalena, sugieren una espacialidad figurativa, donde las diferentes identidades que los acompañan, evidencian las potencialidades agentivas de la corporalidad, en el marco de una ontología de captación hibrida. El cuerpo chamanizado era un cuerpo de devenires multiples, que variaba de apariencia de la misma forma que si se tratara de cambiar de “traje”. Porque consiste en el cambio de posición entre el soma (forma referente) y el sema (significado), que inserta en la percepción del cuerpo prehispánico, cierto monismo, si se quiere filosófico.Abstract. The late pre-Hispanic societies inhabiting the slopes of the Alto-median and Middle Magdalena river until the dawn of the European invasion (16th century), had a perception of human physicality, linked to the objects and artifacts. Body and artifacts ran more or less in the same way, because they were treated by the pre-Hispanic as a container: container, content and continent. Description plastic bodies modeled in clay on the cover of the funeral urns of the Magdalena river, they suggest a figurative spatiality, where different identities that accompany them, reveal the agentivas potential of physicality, in the framework of an ontology of catchment hybrid. Chamanizado body was a body of becomings multiple, varying in appearance in the same way as if it were the change of "costume". Because it consists change of position between the soma (reference form) and the sema (meaning), to insert in the perception of the prehispanic body, true monism, whether philosophical.Maestrí

Mechanical, electrical and sensing properties of melt-spun polymer fibers filled with carbon nanoparticles

Multifunctional polymer fibers with strain and liquid sensing capabilities were fabricated and characterized. The Hansen Solubility Parameters (HSPs) were used as a tool for selecting a suitable polymer to employ as matrix for the sensing material before fiber fabrication. The addition of conductive carbon particles to a polymer matrix provides it with sensing capabilities, such as against tensile strain and the presence of liquids as it was evaluated in this work. Multiwall carbon nanotubes (MWCNTs, MW) as well as a mixture of carbon black (CB) and MWCNTs in weight concentration of 1:1 were used as conductive fillers. The route followed to achieve electrically conductive polymer fibers necessary for sensing evaluations was a combined process of melt-mixing and subsequent melt-spinning. Melt-mixing and melt-spinning are processing techniques widely used in the polymer industry that could enable the up-scaling of the fibers developed in this work. Additionally to single component fibers, bi-component (BICO) fibers consisting of a polycarbonate (PC)+CB+MW sheath and a neat PC core were also fabricated, characterized and their performance was compared to the single component fibers. The state of dispersion of the carbon nanoparticles (CNPs) as well as tensile behavior, electrical resistivity, strain and liquid sensing properties of the composite fibers were evaluated. Finally a specific fiber composition with potential to be used as sensing material for mechanical strain and liquid exposition was proposed to be tested under two real situations (strain monitoring of a rigid structure and leakage detection of a chemical substance). Sensing fibers as the developed in this work have many potential applications such as real-time deformation and structural health monitoring and early cracking detection of any kind of structure. On the other hand, fibers able to sense the presence of liquids can perceive the leakage of chemicals that are hazardous to life. Moreover, this technology can also be applied in smart clothing manufacture by combining sensing fibers with flexible woven electronics

Mechanical, electrical and sensing properties of melt-spun polymer fibers filled with carbon nanoparticles

Multifunctional polymer fibers with strain and liquid sensing capabilities were fabricated and characterized. The Hansen Solubility Parameters (HSPs) were used as a tool for selecting a suitable polymer to employ as matrix for the sensing material before fiber fabrication. The addition of conductive carbon particles to a polymer matrix provides it with sensing capabilities, such as against tensile strain and the presence of liquids as it was evaluated in this work. Multiwall carbon nanotubes (MWCNTs, MW) as well as a mixture of carbon black (CB) and MWCNTs in weight concentration of 1:1 were used as conductive fillers. The route followed to achieve electrically conductive polymer fibers necessary for sensing evaluations was a combined process of melt-mixing and subsequent melt-spinning. Melt-mixing and melt-spinning are processing techniques widely used in the polymer industry that could enable the up-scaling of the fibers developed in this work. Additionally to single component fibers, bi-component (BICO) fibers consisting of a polycarbonate (PC)+CB+MW sheath and a neat PC core were also fabricated, characterized and their performance was compared to the single component fibers. The state of dispersion of the carbon nanoparticles (CNPs) as well as tensile behavior, electrical resistivity, strain and liquid sensing properties of the composite fibers were evaluated. Finally a specific fiber composition with potential to be used as sensing material for mechanical strain and liquid exposition was proposed to be tested under two real situations (strain monitoring of a rigid structure and leakage detection of a chemical substance). Sensing fibers as the developed in this work have many potential applications such as real-time deformation and structural health monitoring and early cracking detection of any kind of structure. On the other hand, fibers able to sense the presence of liquids can perceive the leakage of chemicals that are hazardous to life. Moreover, this technology can also be applied in smart clothing manufacture by combining sensing fibers with flexible woven electronics

DEVELOPMENT OF SCIENTIFIC THINKING: A DIDACTICAL STRATEGY FOR CHILDREN OF ALTOS DE CAZUCÁ AIMED TO INTRODUCE THEM TO THE TEMPERATURE NOTION

La presente propuesta investigativa nace del trabajo de campo realizado en la Corporación Social Fe y Esperanza ubicada en Cazucá en el Barrio el Progreso. Esta propuesta ha permitido emprender una reflexión sobre la difícil situación que viven los niños por causa deldesplazamiento y las condiciones de pobreza de su entorno. La intención es llevar a esteescenario educativo una estrategia didáctica que favorezca el desarrollo de habilidades de pensamiento científico aproximándolos a la noción de temperatura. La propuesta investigativa favorece la recreación de espacios donde los niños desarrollen la capacidad de hacer preguntas, observar eventos, realizar descripciones sencillas y explicar algunos fenómenos naturales de su entorno; así mismo, es una opción para visualizar y diseñar nuevas alternativas para llevar la ciencia a los niños de estos contextos, estimulando su gusto por curiosear e indagar sobre lo que a su alrededor ocurre, explotando al máximo los espacios que para su estimulación ofrece el lugar donde habitan.This work evolves from our intervention at the institution “Corporación Social Fé y Esperanza” at Bogota, Colombia. This work has been an opportunity to reflect on the harsh context the children has to endure due to their condition of being displaced from their home land. We aim to put forward a didactical strategy to improve the development of scientific thinking’s skills by approaching them to de concept of temperature. In this strategy we set up contexts in which the students develop their ability to make question, to observe events, to realize description and to explain some natural phenomena of their environment. It is an option to see an design new ways to present science to children belonging to this contexts, by stimulating their taste to inquire and research on what happen in their surroundings, as well