POTENCIALES ENERGÉTICOS DE TIPO RENOVABLE PENDIENTES DE DESARROLLO

La presente disertación doctoral trata sobre el desarrollo de potenciales de energía renovable, en particular, sobre la energía eólica. Los logros más importantes se presentan a continuación: i) desarrollo de una elaborada teoría sobre álabes rotantes; ii) desarrollo de un nuevo mecanismo centrífugo para la regulación de los álabes pivotantes de una turbina eólica tipo S-VAWT; iii) fabricación de prototipos de aerogeneradores mediante técnicas de impresión en 3D; iv) cuantificación del efecto de las condiciones ambientales en la determinación de la velocidad del viento a través de anemómetros de cucharillas; v) desarrollo de un sistema de medición para la determinación de la viscosidad cinemática y la densidad del aire húmedoThe present doctoral dissertation deals with the development of renewable energy potentials, in particular, with wind energy. The most important achievements are presented as follows: i) the development of an elaborated theory about rotating blades; ii) development of a new centrifugal mechanism for the regulation of rotating blades S-VAWT; iii) manufacturing of wind turbine prototypes via 3D printing techniques; iv) quantification of the effect of ambient conditions on the determination of wind speed via cup anemometers; v) development of a measurement system for kinematic viscosity and moist air density determination.Tesis Univ. Jaén. Departamento de Ingeniería Mecánica y Minera. Leída el 26 de octubre de 2018

AN INVESTIGATION INTO SURFACE FINISH IMPROVEMENT OF SMALL PLASTIC PARTS MANUFACTURED THROUGH ADDITIVE MANUFACTURING

Published ThesisNowadays, Additive Manufacturing (AM), also known as 3D printing finds wide application in automotive, aerospace and medical fields. Functional additive manufactured parts must satisfy dimensional accuracy as well as to provide an acceptable quality of surface finish. However the dimensional accuracy of additive manufactured parts are affected by many process variables including accuracy of tessellation from Computer Aided Design (CAD) model, slicing algorithm, data transfer, device motion resolution, powder granulometry, beam offset, process parameters and shrinkage. The surface finish of additive manufactured parts is often poor due to the layer-by-layer manufacturing process of AM. The degree of this so called “stairstepping” is dependent on the type of AM process and layer thickness used. Different post processing techniques can be used to improve the surface finish. Six post processing techniques were investigated in this study to improve the surface finish of small test pieces that were additive manufactured in nylon polyamide, Alumide® and Acrylonitrile Butadiene Styrene (ABS) plastic materials. The techniques include tumbling, shot peening, Computer Numerical Control (CNC) machining, spray painting, undercoat and hand finishing and chemical treatment by dissolving the surface of the test pieces. A Laser Sintering (LS) process was used to manufacture the nylon polyamide and Alumide® test pieces while Fused Deposition Modelling (FDM) was used for the ABS test pieces. A Coordinate Measuring Machine (CMM) also known as Touch probe scan machine was used for assessment of the dimensional accuracy of post processed test pieces compared to the geometry of the “as built” test pieces. The Chisquare test ( 2 ) and the test for differences in deviation range proportions were used to establish the level of significance of differences between ‘“as built” and each post processing technique. It was shown that there exists a significant difference between deviation range proportions as one compares the “as built” to any one of the six considered post processing techniques. For all the three investigated materials, hand finishing technique produced the best improvement of surface finish though this technique was generally characterized by a lack of consistency in distribution of uniform deviation ranges across individual surfaces as well as across entire test pieces. The spray painting improved the surface finish and was found to be consistent in distribution of uniform deviation ranges across individual surfaces as well as across entire test pieces. However this technique led to significant positive deviation ranges from the geometry of the “as built” test piece, thus affecting negatively the dimensional accuracy of the “as built” test piece. On one hand, despite the rounding of the sharp corners and the removal of small protrusions, tumbling and shot peening techniques, without affecting negatively the dimensional accuracy of the test piece, it was found that tumbling and shot peening are the optimal post processing techniques to improve the surface finish of relatively wide surfaces of Laser Sintered nylon and Alumide® test pieces. On the other hand, it was realized that tumbling or shot peening technique should not be applied to ABS test pieces as, in addition to the negative effects of the two techniques on nylon and Alumide® test pieces, tumbling and shot peening damage heavily the surfaces of ABS pieces. Chemical treatment by immersion into acetone bath was found to be the optimal technique for improvement of the surface finish of Fused Deposition Modelled ABS test pieces. Though through CNC machining the surface finish of nylon, Alumide® and ABS test pieces was improved, a relatively high standard deviation in surface finish across the entire test piece was observed. In addition to this, excessive negative deviation ranges were observed on the machined surfaces. This can be attributed to a single error during the calibration of the machine or the setting of the cutting parameters which led to the excessive negative deviation ranges from the geometry of the “as built” test piece. The consideration of individual cutting parameters for each surface inclination angle would reduce the standard deviation and eliminate the risk of excessive negative deviation ranges across the entire test piece. However, this approach would lead to excessive machining time, thus increasing the cost of the process. Finally, it was realized that CNC machining is not an appropriate technique to improve the surface finish of small plastic parts with complex shapes in the form of various inclination angles and small entities such as small conical features, round cavities and protrusions

Fused deposition modelling (FDM) to fabricate a transitional vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) for transportation of medical supplies in underdeveloped areas.

Masters Degree. University of KwaZulu- Natal, Durban.This dissertation’s work has focused on the design and development of a prototype UAV that aims to facilitate the delivery of emergency medical aid supplies to remote locations within South Africa (SA). This research has conducted a conceptualized design of a tilt-rotor VTOL UAV named Airslipper, which was entirely fabricated using FDM methods. Identification of key performance parameters within the vehicle’s mechatronic design enabled this research to conduct a simultaneous optimization on the propeller-based propulsion system and aerodynamic configuration. Execution of MATLAB’s ‘gamultiobj’ function on two parametrically formulated objective functions resulted in a UAV setup that increased flight endurance by 8 . This improvement amplified the effectiveness of this system and expanded the service radius distance by .1 m. The outcome of a stability and sensitivity analysis performed on the Airslipper’s aerodynamic surfaces provided critical information that contributed towards the vehicle’s flight characteristics. Findings indicated a stabilized design that exhibited appropriate frequency plots for both longitudinal and lateral stability modes. The addition of a plane analysis, which included viscous and inertial effects, offered essential drag and pressure coefficients, which aided in the final design. This research correspondingly conducted several CFD simulations on an Airslipper model, which allowed this work to examine further the fluid behaviour characteristics endured on the vehicle in both VTOL and Fixed Wing (FW) modes. Simulation findings revealed standard pressure distributions, which confirmed thrust and lift forces for the relevant components without performance compromise. This research proposed to experimentally investigate a correction factor for an FDM fabricated aerofoil that aimed to determine what structural effects were apparent for a printed part with varying FDM parameters. Outcomes demonstrated greater resilience to failure for parts that had reduced layer heights and increased infill percentages. Fabrication of the Airslipper comprised of 99 individually printed parts that encompassed a specific parameter combination which pertained to the design’s importance. Validating the prototype’s functionality was achieved through a series of hover tests that generated suitable data logs plots for the control response, actuator output signals, vibration metrics, and power. This research concluded by discussing the Airslipper’s design and fabrication method with further mentioning of recommendations for potential improvements

Fused deposition modeling: process, materials, parameters, properties, and applications

In recent years, 3D printing technology has played an essential role in fabricating customized products at a low cost and faster in numerous industrial sectors. Fused deposition modeling (FDM) is one of the most efficient and economical 3D printing techniques. Various materials have been developed and studied, and their properties, such as mechanical, thermal, and electrical, have been reported. Numerous attempts to improve FDM products’ properties for applications in various sectors have also been reported. Still, their applications are limited due to the materials’ availability and properties compared to traditional fabrication methods. In 3D printing, the process parameters are crucial factors for improving the product's properties and reducing the machining time and cost. Researchers have recently investigated many approaches for expanding the range of materials and optimizing the FDM process parameters to extend the FDM process’s possibility into various industrial sectors. This paper reviews and explains various techniques used in 3D printing and the various polymers and polymer composites used in the FDM process. The list of mechanical investigations carried out for different materials, process parameters, properties, and the FDM process's potential application was discussed. This review is expected to indicate the materials and their optimized parameters to achieve enhanced properties and applications. Also, the article is highly anticipated to provide the research gaps to sustenance future research in the area of FDM technologies

Beyond Rapid Prototyping: automation of robotic 3D printing for construction

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Informática, Departamento de Ingeniería del Software e Inteligencia Artificial, leída el 18-04-2017La fabricación aditiva se desarrolló por vez primera hace más de 20 años. A pesar de este hecho,se ha mantenido encapsulada y aislada como una técnica de prototipado rápido hasta su eclosión y su crecimiento exponencial subsiguiente, experimentado en los últimos 10 años. Como consecuencia, la fabricación aditiva se considera una de las tecnologías más disruptivas del siglo, capaz de dar forma al futuro de la fabricación.Las técnicas de prototipado rápido ya han llegado al público en general, permitiendo la emergencia de nuevos modelos de fabricación y distribución a muchos niveles. No obstante, muchas aplicaciones profesionales de la impresión en 3D están aún por explorar. La tesis se centra en la impresión 3D para la construcción, que se encuentra estancada en una etapa temprana de desarrollo, especialmente en lo relativo a materiales y productos finales de gran tamaño. Algunos esfuerzos se han llevado a cabo en esta dirección,con vistas a aumentar la capacidad de la tecnología en cuestiones de tamaño, velocidad, o variedad demateriales. En la presente investigación se analizan los tres ámbitos, dentro de un marco sistémico y que sirve como base para el desarrollo de aplicaciones de fabricación aditiva con fines industriales, basados en el empleo de robots de seis ejes. Por lo tanto, es posible superar las limitaciones actuales de la tecnología de impresión 3D en términos de sus aplicaciones en la industria de la arquitectura, ingeniería y la construcción (AEC), lo que representa la versatilidad de la herramienta, materiales, calidad de acabado, y las cuestiones ambientales que dicha tecnología implica...Additive Manufacturing was first developed more than 20 years ago. Despite this fact, it hasremained encapsulated as a Rapid Prototyping technique until its eruption and subsequent exponentialgrowth, which it has experienced in the last 10 years, being considered, as a consequence, one of the mostdisruptive technologies to shape the future of fabrication.Rapid prototyping techniques have already reached the general public, causing new fabricationand distribution models to arise at many levels. Nonetheless, many professional applications of 3D printingstay unexplored. The thesis focuses on 3D printing for construction, which is stagnated at an early stage ofdevelopment, especially regarding materials and oversized final products. Some efforts have been carriedout in this direction, aiming at increasing size, speed, or materials. The current research discusses all three,within a globally interrelated systemic framework that serves as basis for the development of industrial,robot-based Additive Manufacturing applications. Thus, it is possible to overcome the current limitationsof 3D printing technology in terms of its applications in the AEC industries, accounting for tool versatility,materials, finish quality, and environmental issues...Depto. de Ingeniería de Software e Inteligencia Artificial (ISIA)Fac. de InformáticaTRUEunpu

Aeronautical engineering: A cumulative index to a continuing bibliography

This bibliography is a cumulative index to the abstracts contained in NASA SP-7037 (197) through NASA SP-7037 (208) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, foreign technology, contract, report number, and accession number indexes

Expanding the Horizons of Manufacturing: Towards Wide Integration, Smart Systems and Tools

This research topic aims at enterprise-wide modeling and optimization (EWMO) through the development and application of integrated modeling, simulation and optimization methodologies, and computer-aided tools for reliable and sustainable improvement opportunities within the entire manufacturing network (raw materials, production plants, distribution, retailers, and customers) and its components. This integrated approach incorporates information from the local primary control and supervisory modules into the scheduling/planning formulation. That makes it possible to dynamically react to incidents that occur in the network components at the appropriate decision-making level, requiring fewer resources, emitting less waste, and allowing for better responsiveness in changing market requirements and operational variations, reducing cost, waste, energy consumption and environmental impact, and increasing the benefits. More recently, the exploitation of new technology integration, such as through semantic models in formal knowledge models, allows for the capture and utilization of domain knowledge, human knowledge, and expert knowledge toward comprehensive intelligent management. Otherwise, the development of advanced technologies and tools, such as cyber-physical systems, the Internet of Things, the Industrial Internet of Things, Artificial Intelligence, Big Data, Cloud Computing, Blockchain, etc., have captured the attention of manufacturing enterprises toward intelligent manufacturing systems

Proceedings of the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008

This volume contains full papers presented at the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008, held in Braga, Portugal, between September 4th and 6th, 2008.FC