Effect of Surface Preparation Methods on Mechanical Properties of 3D Structures Fabricated by Stereolithography and 3D Printing for Electroless Ni Plating

Stereolithography (SL) and 3D Printing (3DP) are useful technologies for three-dimensional prototyping applications, providing highly accurate and detailed part geometries with high quality surface finishes. It is desired to improve the materials performance of the existing photocurable SL and 3DP resins for rapid tooling and other functional applications by applying a nickel (Ni) coating. In this work, surface preparation methods for electroless plating of commercial photopolymer resins such as NanoFormTM15120 (NanoForm) and Objet FullCure®840 (Veroblue) were explored in order to enhance the structural integrity of RP components. This study examined different surface preparation methods (chemical etching) and their effect on the surface morphology and mechanical strength of the polymers. It was observed that surface preparation of the resins significantly affected the mechanical properties and Ni plating of the substrate polymers. This is a critical step, since the Ni film takes on the surface structure of the substrate.Mechanical Engineerin

Development of an Automated Multiple Material Stereolithography Machine

An automated Multiple Material Stereolithography (MMSL) machine was developed by integrating components of a 3D Systems 250/50 stereolithography (SL) machine in a separate stand-alone system and adapting them to function with additional components required for MMSL operation. We previously reported retrofitting a 250/50 SL machine with multiple vats to accommodate multiple material fabrication for building a wide variety of multi-material models (Wicker et al., 2004). In the MMSL retrofit, spatial constraints limited the multiple vats located circumferentially on a vertical rotating vat carousel to cross-sectional areas of approximately 4.5-inches by 4.5-inches. The limited build size of the retrofitted 250/50 motivated the full development of a new system with multiple material build capabilities comparable to the build envelope of the original 250/50 machine. The new MMSL machine required fabrication of a large system frame, incorporating various 250/50 components and software, and adding a variety of new components and software. By using many existing components and software, the previous engineering development of 3D Systems could be directly applied to this new technology. Components that were transferred from an existing 250/50 to the MMSL machine included the complete optical system (including the optics plate with laser, mirrors, beam expander, scanning mirrors, and focusing lens), the rim assembly (including the laser beam profilers), the associated controllers (computer system, scanning mirror controller, power supply-vat controller) and the wiring harness. In addition to the new frame, the MMSL machine required the development of a new rotating vat carousel system, platform assembly, multi-pump filling/leveling system, and a custom LabVIEW® control system to provide automated control over the MMSL process. The overall operation of the MMSL system was managed using the LabVIEW® program, which also included controlling a new vat leveling system and new linear and rotational stages, while the 3D Systems software (Buildstation 4.0) was retained for controlling the laser scanning process. As a demonstration of MMSL technology, simple multi material parts were fabricated with vertically and horizontally oriented interfaces. The fully functional MMSL system offers enormous potential for fabricating a wide variety of multiple material functional devices.Mechanical Engineerin

Experiencia del proyecto para la implementación de préstamo de libros electrónicos y lectores de libros electrónicos en la División de Bibliotecas de la Universidad del Valle

This proceeding shows the achievements in the “proyecto para la implementación de préstamo de libros electrónicos y lectores de libros electrónicos en la División de Bibliotecas de la Universidad del Valle” (e-books and e-readers lending service at "División de Bibliotecas de la Universidad del Valle" project) starting from the approach of the particular academic community "Universidad del Valle"'s requirements; resources and devices marketing for e-books and e-readers analysis; similar experiences in the world referencing, and finally the accomplishments highlighting the importance of include e-readers to colombian public university libraries

Hybrid Manufacturing: Integrating Direct Write and Stereolithography

A commercial stereolithography (SL) machine was modified to integrate fluid dispensing or direct-write (DW) technology with SL in an integrated manufacturing environment for automated and efficient hybrid manufacturing of complex electrical devices, combining threedimensional (3D) electrical circuitry with SL-manufactured parts. The modified SL system operates similarly to a commercially available machine, although build interrupts were used to stop and start the SL build while depositing fluid using the DW system. An additional linear encoder was attached to the SL platform z-stage and used to maintain accurate part registration during the SL and DW build processes. Individual STL files were required as part of the manufacturing process plan. The DW system employed a three-axis translation mechanism that was integrated with the commercial SL machine. Registration between the SL part, SL laser and the DW nozzle was maintained through the use of 0.025-inch diameter cylindrical reference holes manufactured in the part during SL. After depositing conductive ink using DW, the SL laser was commanded to trace the profile until the ink was cured. The current system allows for easy exchange between SL and DW in order to manufacture fully functional 3D electrical circuits and structures in a semi-automated environment. To demonstrate the manufacturing capabilities, the hybrid SL/DW setup was used to make a simple multi-layer SL part with embedded circuitry. This hybrid system is not intended to function as a commercial system, it is intended for experimental demonstration only. This hybrid SL/DW system has the potential for manufacturing fully functional electromechanical devices that are more compact, less expensive, and more reliable than their conventional predecessors, and work is ongoing in order to fully automate the current system.Mechanical Engineerin

Radiation mitigation of the intestinal acute radiation injury in mice by 1-[(4-nitrophenyl)sulfonyl]-4-phenylpiperazine.

The objective of the study was to identify the mechanism of action for a radiation mitigator of the gastrointestinal (GI) acute radiation syndrome (ARS), identified in an unbiased high-throughput screen. We used mice irradiated with a lethal dose of radiation and treated with daily injections of the radiation mitigator 1-[(4-nitrophenyl)sulfonyl]-4-phenylpiperazine to study its effects on key pathways involved in intestinal stem cell (ISC) maintenance. RNASeq, quantitative reverse transcriptase-polymerase chain reaction, and immunohistochemistry were performed to identify pathways engaged after drug treatment. Target validation was performed with competition assays, reporter cells, and in silico docking. 1-[(4-Nitrophenyl)sulfonyl]-4-phenylpiperazine activates Hedgehog signaling by binding to the transmembrane domain of Smoothened, thereby expanding the ISC pool, increasing the number of regenerating crypts and preventing the GI-ARS. We conclude that Smoothened is a target for radiation mitigation in the small intestine that could be explored for use in radiation accidents as well as to mitigate normal tissue toxicity during and after radiotherapy of the abdomen

Evaluation of the impact of an open educational resource for the development of informational skills in access to information for three groups of university students

El Desarrollo de Habilidades Informacionales (DHI) también llamado Alfabetización Informacional es un modelo metodológico para estructurar la formación de usuarios en el acceso, uso y evaluación de la información, implementado en las bibliotecas e instituciones educativas donde gana cada vez mayor aceptación, al igual que los Recursos Educativos Abiertos (REA) en el marco de la educación virtual. Fusionando ambos conceptos ¿qué impacto tendría entonces un REA para el DHI en el Acceso a la información (READHI-Ai) para los saberes DHI de tres grupos de estudiantes universitarios? Este estudio contó con una muestra de 60 estudiantes de la Universidad del Valle (Cali-Colombia) que realizaban estudios en programas de pregrado y posgrado. Utilizando una metodología mixta, este proyecto desarrolló entre sus instrumentos cuestionarios y encuestas, cada uno con versiones pre y post, cuyos resultados en conjunto validaron la hipótesis del autor a través de estrategias de análisis cuantitativo, cualitativo y mixto. Entre los principales hallazgos se obtuvo que los participantes presentaron una mejora en los saberes DHI después de usar el READHI-Ai y también se encontró que su efectividad no solo es dada por sus contenidos sino también por factores como la inclusión del programa en el currículo académico; el trabajo colaborativo con el cuerpo docente, bibliotecario y administrativo en la creación del recurso educativo; y la exclusividad de contenidos según el programa y el nivel educativo del participante.Instituto Tecnológico de Estudios Superiores de Monterrey ITESM1. Capítulo 1 - Marco Teórico......................................................................... 1 1.1. Desarrollo de habilidades informacionales............................................. 1 1.1.1. Programa para el desarrollo de habilidades informacionales........... 2 1.1.2. Modelo IFLA para un programa de desarrollo de habilidades informacionales................................................................................. 3 1.2. Recursos Educativos Abiertos para el desarrollo de habilidades informacionales......................................................................................... 5 1.2.1. Recursos Educativos Abiertos............................................................ 6 1.3. Diseño de recursos educativos.................................................................. 6 1.3.1. Criterios estructurales....................................................................... 7 1.3.2. Criterios pedagógicos....................................................................... 7 1.3.3. Criterios tecnológicos....................................................................... 8 1.4. Producción de REA.................................................................................. 9 1.4.1. Software........................................................................................... 9 1.5. Ensamble de los REA.............................................................................. 10 1.6. Mecanismos de evaluación....................................................................... 11 1.7. Integración de conceptos.......................................................................... 11 2. Capítulo 2 - Planteamiento del problema.................................................. 13 2.1. Antecedentes............................................................................................ 13 2.2. Planteamiento del problema..................................................................... 14 2.3. Objetivos.................................................................................................. 14 2.3.1. Objetivo general............................................................................... 14 2.3.2. Objetivos específicos....................................................................... 14 2.4. Justificación............................................................................................. 15 2.5. Delimitaciones......................................................................................... 15 3. Capítulo 3 - Metodología.............................................................................. 17 3.1. Enfoque metodológico.............................................................................. 17 3.2. Participantes............................................................................................. 18 3.3. Instrumentos............................................................................................. 18 3.3.1. Encuesta de saberes conceptuales.................................................. 18 3.3.1.1. Encuesta de saberes conceptuales iniciales....................... 19 3.3.1.2. Encuesta de saberes conceptuales final............................. 19 3.3.2. Cuestionario de saberes en aplicación contextual........................ 20 3.3.3. Encuestas de satisfacción.............................................................. 21 3.3.3.1. Encuesta de motivación inicial........................................ 21 3.3.3.2. Encuesta de satisfacción final........................................... 21 3.4. Procedimientos......................................................................................... 22 3.5. Estrategia de análisis de datos.................................................................. 23 4. Capítulo 4 - Análisis de resultados.............................................................. 24 4.1. Preparación de datos................................................................................ 24 4.2. Análisis de resultados por categorías....................................................... 24 4.2.1. Aprendizaje de saberes conceptuales............................................. 24 4.2.1.1. Análisis grupo 1...................................................................26 4.2.1.2. Análisis grupo 2...................................................................26 4.2.1.3. Análisis grupo 3...................................................................26 4.2.2. Transferencia de saberes ................................................................. 27 4.2.1.1. Análisis grupo 1...................................................................28 4.2.1.2. Análisis grupo 2...................................................................28 4.2.1.3. Análisis grupo 3...................................................................29 4.2.3. Satisfacción...................................................................................... 29 4.3. Validación de la hipótesis......................................................................... 31 4.3.1. Hipótesis categoría conceptualización............................................ 32 4.3.2. Hipótesis categoría aplicación-transferencia.................................. 34 4.3.3. Hipótesis categoría satisfacción. .................................................... 36 4.3.4. Triangulación.................................................................................. 37 4.4. Conclusiones............................................................................................. 39 5. Capítulo 5 - Conclusiones.............................................................................. 40 5.1. Conclusiones............................................................................................ 40 5.2. Limitaciones............................................................................................. 41 5.3. Recomendaciones.................................................................................... 42 Referencias.............................................................................................................. 43 Apéndices................................................................................................................. 49 Apéndice A: Solicitud de permiso y carta de autorización............................ 49 Apéndice B: Carta de autorización................................................................. 50 Apéndice C: Algunas interfaces gráficas del READHI-Ai............................ 51 Apéndice D: Encuesta de saberes conceptuales iniciales............................... 53 Apéndice E: Encuesta de saberes conceptuales final..................................... 54 Apéndice F: Cuestionario de saberes en aplicación contextual...................... 56 Apéndice G: Encuesta de satisfacción final..................................................... 57 Currículum Vitae..................................................................................................... 58MaestríaThe Development of Informational Skills (DHI) also called Informational Literacy is a methodological model to structure the training of users in the access, use and evaluation of information, implemented in libraries and educational institutions where it is gaining increasing acceptance, as well as Open Educational Resources (OER) within the framework of virtual education. Merging both concepts, what impact would an OER for DHI on Access to Information (READHI-Ai) have for the DHI knowledge of three groups of university students? This study had a sample of 60 students from the Universidad del Valle (Cali-Colombia) who were studying in undergraduate and graduate programs. Using a mixed methodology, this project developed questionnaires and surveys among its instruments, each one with pre and post versions, the results of which together validated the author's hypothesis through quantitative, qualitative and mixed analysis strategies. Among the main findings, it was obtained that the participants presented an improvement in DHI knowledge after using the READHI-Ai and it was also found that its effectiveness is not only given by its contents but also by factors such as the inclusion of the program in the academic curriculum ; collaborative work with the teaching, librarian and administrative body in the creation of the educational resource; and the exclusivity of content according to the program and the educational level of the participant.Modalidad Presencia