Developing Biomimetic Design Principles for the Highly Optimized and Robust Design of Products and Their Components

Engineering design methods focus on developing products that are innovative, robust, and multi-functional. In this context, the term robust refers to a product's ability to accomplish successfully its predetermined functions. Owing to the abundance of optimized and robust biological systems, engineering designers are now looking to nature for inspiration. Researchers believe that biomimetic or bio-inspired engineering systems can leverage the principles, mechanisms, processes, strategies, and/or morphologies of nature's successful designs. Unfortunately, two important problems associated with biomimetic design are a designer's limited knowledge of biology and the difference in biological and engineering terminologies. This research developed a new design tool that addresses these problems and proposes to help engineering designers develop candidate bio-inspired products or solutions. A methodology that helps users infer or extract biomimetic design principles from a given natural system or biomimetic product pair is described in this thesis. The method incorporates and integrates five existing design tools and theories to comprehensively investigate a given natural system or biomimetic product. Subsequently, this method is used to extract biomimetic design principles from 23 biomimetic products and natural systems. It is proposed that these principles have the potential to inspire ideas for candidate biomimetic products that are novel, innovative, and robust. The principle extraction methodology and the identified principles are validated using two separate case studies and a detailed analysis using the validation square framework. In the first case study, two students and the author use the principle extraction methodology to extract characteristics from a natural system and a biomimetic product pair. Results from this case study showed that the methodology effectively and repeatedly identifies system characteristics that exemplify inherent biomimetic design principles. In the second case study, the developed biomimetic design principles are used to inspire a solution for an engineering design problem. The resulting solution and its evaluation show that the design's achieved usefulness is linked to applying the biomimetic design principles. Similar to the TRIZ principles, the biomimetic design principles can inspire ideas for solutions to a given problem. The key difference is that designers using TRIZ leverage the solution strategies of engineering patents, while designers using the biomimetic design principles leverage nature’s solution strategies. The biomimetic design principles are compared to TRIZ and the BioTRIZ matrix

Advances in Optofluidics

Optofluidics a niche research field that integrates optics with microfluidics. It started with elegant demonstrations of the passive interaction of light and liquid media such as liquid waveguides and liquid tunable lenses. Recently, the optofluidics continues the advance in liquid-based optical devices/systems. In addition, it has expanded rapidly into many other fields that involve lightwave (or photon) and liquid media. This Special Issue invites review articles (only review articles) that update the latest progress of the optofluidics in various aspects, such as new functional devices, new integrated systems, new fabrication techniques, new applications, etc. It covers, but is not limited to, topics such as micro-optics in liquid media, optofluidic sensors, integrated micro-optical systems, displays, optofluidics-on-fibers, optofluidic manipulation, energy and environmental applciations, and so on

Integration of Biomolecular Recognition Elements with Solid-State Devices

Continued advances in stand-alone chemical sensors requires the introduction of new materials and transducers, and the seamless integration of the two. Electronic sensors represent one of the most efficient and versatile sensing transducers that offer advantages of high sensitivity, compatibility with multiple types of materials, network connectivity, and capability of miniaturization. With respect to materials to be used on this platform, many classes and subclasses of materials, including polymers, oxides, semiconductors, and composites have been investigated for various sensing environments. Despite numerous commercial products, major challenges remain. These include enhancing materials for selectivity/specificity, and low cost integration/ miniaturization of devices. Breakthroughs in either area would signify a transformative innovation. In this thesis, a combined materials and devices approach has been explored to address the above challenges. Biomolecular recognition elements, exemplified by aptamers, are the most recent addition to the library of tunable materials for specific detection of analytes. At the same time, nanoscale electrical devices based on tunnel junctions offer the potential for simple design, large scale integration, field deployment, network connectivity, and importantly, miniaturization to the molecular scale. To first establish a framework for studying sorption properties of solid oligonucleotides, custom designed aptamers sequences were studied to determine equilibrium partition coefficients. Linear-solvation-energy-relationship (LSER) analysis provides quantifications of non-covalent bonding properties and reveals the dominance of hydrogen bonding basicity in oligonucleotides. We find that DNA-analyte interactions have selective sorption properties similar to synthetic polymers. LSER analysis provides a chemical basis for material-analyte interactions. Oligonucleotide sequences were integrated with gold nanoparticle chemiresistors to transfer the selective sorption properties to microfabricated electrical devices. Responses generated by oligonucleotides under dry conditions were similar to standard organic mediums used as capping agents and suggests that DNA-based chemiresistor sensors operate with a similar mechanism based on sorption induced swelling. The equilibrium mass-sorption behavior of bulk DNA films could be translated to the chemiresistor sensitivity profiles. Our work establishes oligonucleotides, including aptamers, as a class of sorptive materials that can be systematically studied, engineered, and integrated with nanoscale electronic sensor devices. Experiments to investigate secondary structure effects were inconclusive and we conclude that further work should investigate DNA aptamers in buffered, aqueous environments to unequivocally establish the ability of chemiresitors to signal molecular recognition. Concurrent with the above studies, device integration and miniaturization was investigated to combine many sensing materials into a single, compact design. Arrays of nanoscale chemiresistors with critical features on the order of 10 – 100 nm were developed, using dielectrophoretic assembly of gold nanoparticles to control placement of the sensing material with nanometer accuracy. The nanoscale chemiresistors achieved the smallest known gold nanoparticle chemiresistors relying on just 2 – 3 layers of nanoparticles within 50 nm gaps, and were found to be more robust and less dependent on film thickness than previously published designs. Due to shorter diffusion paths, the sensors are also faster in response and recovery. A proof-of-concept, integrated single-chip sensor array was created and it showed similar response patterns as non-integrated sensor arrays. Dielectrophoresis is established as a key enabler for nanoscale, integrated devices. Based on the major findings of the thesis work, additional investigations were initiated to investigate the potential for nanoscale chemiresitor sensors to operate in buffered, aqueous (liquid) flow cells. Preliminary experiments show that chemiresistor sensing is transferable to liquid environments where analyte molecules are observed to partition from the bulk liquid to the sensing materials, leading to a detectable change of the device electrical properties. Comparing micron- and nano-scale devices fabricated using aqueous oligonucleotide-functionalized gold nanoparticles, it was found that nanoscale chemiresistors are more resistant to solvent damage than 5 µm chemiresistors. We conclude that future experiments to investigate aptamer sensing in aqueous solutions is a promising direction. Overall, this thesis is a significant contribution to materials development and device design to attain improved sensor selectivity and higher levels of device integration. First, it offers a scheme for design, selection, and validation of materials that confer analyte-specific interactions. Second, it paves the way for large scale sensor integration and parallel operation on a single chip. Lastly, it offers an approach to combine biomolecular recognition elements with electronic devices into robust, nanoscale detection systems. Based on the major findings of the thesis work, additional investigations were initiated to investigate the potential for nanoscale chemiresitor sensors to operate in buffered, aqueous (liquid) flow cells. Preliminary experiments show that chemiresistor sensing is transferable to liquid environments where analyte molecules are observed to partition from the bulk liquid to the sensing materials, leading to a detectable change of the device electrical properties. Comparing micron- and nano-scale devices fabricated using aqueous oligonucleotide-functionalized gold nanoparticles, it was found that nanoscale chemiresistors are more resistant to solvent damage than 5 µm chemiresistors. We conclude that future experiments to investigate aptamer sensing in aqueous solutions is a promising direction. Overall, this thesis is a significant contribution to materials development and device design to attain improved sensor selectivity and higher levels of device integration. First, it offers a scheme for design, selection, and validation of materials that confer analyte-specific interactions. Second, it paves the way for large scale sensor integration and parallel operation on a single chip. Lastly, it offers an approach to combine biomolecular recognition elements with electronic devices into robust, nanoscale detection systems

APLICACIÓN AL ESTUDIO DE LA RESPUESTA MECÁNICA DE LA CAPA DE SUBBALASTO DE VÍAS FERROVIARIAS FORMADO POR UNA MEZCLA NO BITUMINOSA DE MATERIAL GRANULAR Y PARTÍCULAS PROCEDENTES DE NEUMÁTICOS FUERA DE USO

Tesis por compendioScrap tyres are a solid waste material which has been generated in large quantities over the last decades. In Spain, between 2000 and 2014 the number of vehicles increased by 30% and a further 3.5% increment is expected for the next fifteen years. Likewise, the number of scrap tyres is also expected to rise within the same order of magnitude. Taking into account the big volume of waste generated, proper disposal and reutilisation management is required, ever more so as scrap tyres are non-biodegradable. Moreover, if simply stockpiled in landfills, further environmental damage may be produced in case of fire as the fumes thus generated carry harmful carcinogenic particles. In order to deal with this problem, a Royal Decree (RD 1481/2001) was approved in July 16, 2006 which completely forbidden landfilling of scrap tyres. Later the same year another Royal Decree (RD 1619/2005) was issued to establish scrap tyres management in Spain. This decree requires reutilisation and recycling plans to be elaborated so as to fully eliminate waste derived from scrap tyres. Nowadays, among the reutilisation options more demanded are tyre remoulding, construction of sport pitches, artificial grass and playpens, and as combustible for cement factories. On the other hand, only 1% of scrap tyres are reused in infrastructure construction. Taking profit of the latest transport plans approved by the European Union, which aim to promote more efficient and environmentally friendly transport means such as railways, this PhD thesis proposes a new and promising alternative: to use rubber particles from scrap tyres as construction material, in the form of unbounded rubber-aggregate mixtures for subballast layers under railway tracks. This option offers two noteworthy environmental advantages. On the one hand, large quantities of a rather problematic and harmful waste material may be reused. On the other hand, the new mixtures proposed help to improve the low resistance to fragmentation of calcareous aggregates, thus allowing the use of such materials in the construction of railway tracks. The objective of this research is to obtain the optimum rubber content for the new mixtures to fulfil all the requirements of subballast layers. Moreover, taking into account the elastic properties of rubber, the potential attenuation of the vibration generated by passing rolling stock is also assessed. As a complementary research, rubber-natural soil mixtures are studied as well so as to evaluate their viability as construction material for embankment cores.El neumático fuera de uso es un residuo sólido que se está generando en grandes cantidades en las últimas décadas. En España, entre los años 2000 y 2014 el parque de vehículos se incrementó en un 30%, y se prevé un aumento del 3.5% para los próximos quince años. Estos datos ponen de manifiesto que el número de neumáticos fuera de uso se incrementará en el mismo orden. Dado el gran volumen de residuo generado, es necesario realizar una gestión de retirada y reutilización de este residuo, al tratarse de una material no biodegradable. Además representa una gran amenaza medioambiental si este residuo termina en vertederos incontrolados, ya que en caso de incineración, los humos que se desprenden arrastran partículas cancerígenas que pueden provocar problemas de salud. Para atajar este problema, el 16 de julio de 2006 entró en vigor el Real Decreto 1481/2001, por el que se prohíbe el depósito en vertedero. A finales de este mismo año también entró en vigor el Real Decreto 1619/2005, sobre la gestión de neumáticos fuera de uso en España, el cual establece que se elaboren planes de reutilización y reciclado para eliminar el total de los residuos derivados de los neumáticos de desecho. En la actualidad, entre las medidas de reutilización más demandadas está el recauchutado, la construcción de pistas deportivas y campos de césped artificial, parques infantiles, y como combustible para centrales de fabricación de cemento. En cambio, en el sector de la construcción se reutiliza menos del 1%. Aprovechando la predisposición de los últimos planes de transporte de la Unión Europea por promover aquellos modos de transporte más eficientes y respetuosos con el medioambiente, como es el ferrocarril, la presente Tesis Doctoral plantea una alternativa adicional y prometedora: el uso de partículas de caucho procedentes de la trituración de los neumáticos como material de construcción, en forma de mezclas de caucho con áridos sin ningún tipo de ligante para ser utilizado como capa de subbalasto en vías ferroviarias. Esta opción ofrece dos ventajas medioambientales importantes. Por un lado, permite la reutilización de grandes cantidades de este residuo considerado peligroso y problemático. Por otro lado, dicha mezcla contribuye a la mejora de la baja resistencia de fragmentación de los áridos calcáreos, pudiendo de esta manera ser reutilizados en capas de asiento en las vías ferroviarias. El objetivo de esta investigación se centra en la obtención del contenido óptimo de caucho para que el nuevo geomaterial cumpla los requerimientos para su uso como capa de subbalasto, y además, dadas las propiedades elásticas del caucho, evaluar el potencial de atenuación de las vibraciones que se generan al paso del tráfico ferroviario. Como investigación complementaria, se han realizado un estudio con mezclas de caucho y suelo natural para comprobar la viabilidad de utilización en núcleos de terraplén.El pneumàtic fora d'ús és un residu sòlid que s'està generant en grans quantitats en les últimes dècades. A Espanya, entre els anys 2000 i 2014 el parc de vehicles es va incrementar en un 30%, i es preveu un augment del 3.5% per als pròxims quinze anys. Estes dades posen de manifest que el nombre de pneumàtics fora d'ús s'incrementarà en el mateix orde. Donat el gran volum de residu generat, és necessari realitzar una gestió de retirada i reutilització d'este residu, al tractar-se d'una material no biodegradable. A més representa una gran amenaça mediambiental si este residu acaba en abocadors incontrolats, ja que en cas d'incineració, els fums que es desprenen arrosseguen partícules cancerígenes que poden provocar problemes de salut. Per a atallar este problema, el 16 de juliol de 2006 va entrar en vigor el Reial Decret 1481/2001, pel qual es prohibeix el depòsit en abocador. A finals d'este mateix any també va entrar en vigor el Reial Decret 1619/2005, sobre la gestió de pneumàtics fora d'ús a Espanya, el qual estableix que s'elaboren plans de reutilització i reciclatge per a eliminar el total dels residus derivats dels pneumàtics de rebuig. En l'actualitat, entre les mesures de reutilització més demandades està el recautxutatge, la construcció de pistes esportives i camps de gespa artificial, parcs infantils, i com a combustible per a centrals de fabricació de ciment. En canvi, en el sector de la construcció es reutilitza menys del 1%. Aprofitant la predisposició dels últims plans de transport de la Unió Europea per promoure aquells modes de transport més eficients i respectuosos amb el mediambient, com és el ferrocarril, la present Tesi Doctoral planteja una alternativa addicional i prometedora: l'ús de partícules de cautxú procedents de la trituració dels pneumàtics com a material de construcció, en forma de mescles de cautxú amb àrids sense cap tipus de lligant per a ser utilitzat com a capa de subbalast en vies ferroviàries. Esta opció ofereix dos avantatges mediambientals importants. D'una banda, permet la reutilització de grans quantitats d'este residu considerat perillós i problemàtic. D'altra banda, la dita mescla contribueix a la millora de la baixa resistència de fragmentació dels àrids calcaris, podent d'esta manera ser reutilitzats en capes d'assient en les vies ferroviàries. L'objectiu d'esta investigació es centra en l'obtenció del contingut òptim de cautxú perquè el nou geomaterial complisca els requeriments per al seu ús com a capa de subbalast, i a més, donades les propietats elàstiques del cautxú, avaluar el potencial d'atenuació de les vibracions que es generen al pas del tràfic ferroviari. Com a investigació complementària, s'han realitzat un estudi amb mescles de cautxú i sòl natural per a comprovar la viabilitat d'utilització en nuclis de terraplè.Hidalgo Signes, C. (2017). APLICACIÓN AL ESTUDIO DE LA RESPUESTA MECÁNICA DE LA CAPA DE SUBBALASTO DE VÍAS FERROVIARIAS FORMADO POR UNA MEZCLA NO BITUMINOSA DE MATERIAL GRANULAR Y PARTÍCULAS PROCEDENTES DE NEUMÁTICOS FUERA DE USO [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86140TESISCompendi