Fluid Rheological Effects on Insulator-Based Dielectrophoresis

Insulator-based dielectrophoresis (iDEP) has been increasingly used to focus, trap and separate particles and cells for various microfluidic applications in the fields of analytical chemistry, bioanalysis, cell biology and clinics etc. It exploits insulating structure(s) to create electric field gradients for dielectrophoretic manipulation of particles and cells in microchannels. However, iDEP has thus far been demonstrated to work with Newtonian fluids only in the majority of the reported applications. As many of the biological (e.g., blood, saliva, DNA solutions, etc.) and chemical (e.g., polymer and colloidal solutions) fluids exhibit non-Newtonian behaviors, it is important and necessary to understand how the fluid rheological properties may affect iDEP. This thesis is aimed to investigate experimentally the effects of fluid elasticity and shear thinning on the iDEP focusing and trapping of particles as well as the electroosmotic flow pattern in two types of microchannels. In the first experiment we study the fluid rheological effects on iDEP focusing and trapping of polystyrene particles in polyethylene oxide (PEO), xanthan gum (XG) and polyacrylamide (PAA) solutions through a constricted microchannel. Such a geometry is the simplest while the most often used structure in iDEP microdevices. Particle focusing and trapping in the mildly viscoelastic PEO solution are found to be slightly weaker than in the Newtonian buffer. They are, however, significantly improved in the strongly viscoelastic and shear thinning PAA solution. These observed particle focusing behaviors exhibit a similar trend with respect to electric field, which is consistent with a revised theoretical analysis for iDEP focusing in non-Newtonian fluids. No apparent focusing of particles is achieved in the XG solution though the iDEP trapping can take place under a much larger electric field than the other fluids. This is attributed to the strong shear thinning-induced influences on both the electroosmotic flow and electrokinetic/dielectrophoretic motions. In the second experiment we investigate the iDEP focusing and trapping of polystyrene particles in the same three types of polymer solutions in a post-array microchannel. Such a geometry has been frequently used to manipulate small particles with submicron and even nanometer sizes. The array of posts causes continuous changes in the non-Newtonian fluid properties. Similar electroosmotic flow pattern and slightly reduced particle focusing are observed in the PEO solution as compared to the Newtonian buffer, which is consistent with the observations in the constricted microchannel. The iDEP focusing and trapping of particles in the PAA solution are only available when the applied DC field is smaller than a certain threshold value. Both effects are, however, weaker than in the buffer solution, opposite to the observations in the constricted microchannel. This phenomenon may be associated with the elongation and relaxation of long PAA molecules as they are advected through the array of posts. Similar to that in the constricted microchannel, the XG solution does not exhibit an apparent iDEP effect on particles in the post-array channel. Interestingly, electroosmotic flow instability occurs under high DC electric fields in the post-array channel only

Estudio y diseño de dispositivos ópticos biosensores depositados con películas delgadas basados en detección de longitud de onda de resonancias

A lo largo de esta tesis se presenta el estudio y diseño de varias plataformas de guía-ondas ópticas, con el fin de ver su viabilidad a la hora de usarlas como biosensores sobre fibra óptica u otros sustratos fotónicos. En este trabajo se depositan estructuras ópticas como una fibra monomodo desnuda, un estrechamiento en fibra óptica o una fusión de fibras mono – multi – monomodo (SMS) con películas delgadas de materiales usando técnicas nanotecnológicas como el ensamblado capa a capa (LbL-assembly) o el sputtering. Además, se dedica un capítulo al estudio de microresonadores toroidales depositados por rotación (spin-coating). El objetivo es generar o mejorar las prestaciones en resolución y sensibilidad de los fenómenos resonantes que se pueden obtener en estas estructuras ópticas, para luego detectar reacciones biológicas que den lugar a un futuro diagnóstico precoz de enfermedades.Along this thesis, the study and design of several optical waveguide platforms is presented, in order to check their viability when used as biosensors based on either optical fiber or other photonic substrates. In this work, some fiber-optic-based structures such as cladding removed multimode structures, tapered single-mode fibers and single-mode – multimode – single-mode fibers are deposited with thin-films of materials, using nanotechnology-based methods such as layer-by-layer assembly (LbL-assembly) or sputtering. Moreover, a brief chapter is focused on the study of toroidal microring resonators deposited by spin-coating. The final objective is to generate or enhance the parameters of the resonant phenomena obtained in these structures, in terms of resolution and sensitivity. Then, a biological detection is addressed and characterized, to see if they are able to perform a future early diagnosis for illnesses.La realización de este trabajo ha sido posible gracias a las aportaciones económicas recibidas por parte de la Universidad Pública de Navarra (UPNA), así como del patrocinio de la UPNA y del Ministerio de Economía y Competitividad, a través de los proyectos CICYT fondos FEDER TEC2010-17805, TEC2013-43679-R e IPT-2011-1212-920000 (PMEL).Programa Oficial de Doctorado en Ingeniería y Arquitectura (RD 1393/2007)Ingeniaritzako eta Arkitekturako Doktoretza Programa Ofiziala (ED 1393/2007

Awareness, Acceptability, and Relevance of the Vision, Mission, Goals, and Objectives of the Programs of Naval State University Graduate School

The study generally aimed to determine the level of awareness, acceptability, and relevance of the vision, mission, goals and objectives of the programs of the NSU graduate school. It utilized the descriptive method of research. The results of the study provide an insight into the awareness, relevance, and acceptance of the students and NSU constituents of the vision, mission, goals and objectives of the graduate programs of the university. The outcome may be beneficial in generating information for the enhancement of the practices of the Graduate school as well as in the dissemination and evaluation of their VMGO. The results revealed that the graduate school students and other respondents of the study were fully aware, fully relevant and fully acceptable of the NSU Vision, and Mission and Graduate School goals and objectives of the different courses. Future research undertakings are conducted similarly to the study in order to increase awareness, relevance, and acceptance especially among newly enrolled graduate students of the university

Job Promotion Practices and its Associated Problems: The Case of Non-Teaching Staff in an Academic Environment

In State Universities and Colleges (SUCs) of the Philippines, guidelines on promotion of support staff is different from the teaching personnel. This study analyzed the practices and problems encountered in the promotion of support staff in the academe. A survey was conducted in the SUCs of Eastern Visayas Region, utilizing a questionnaire patterned from the Philippine

Uso actual y potencialidades del producto local de las Islas Canarias: restaurantes a la carta en hoteles de 4 y 5 estrellas

Máster Universitario en Dirección y Planificación del TurismoThe investigation carried out in this document aims to offer a view on the current usage of the Canary Islands local product by the different a la carte restaurants placed in five and four stars hotels at Tenerife. Thus, the main objective of this investigation is to stablish a comparison between the different restaurants, and to serve as a comparison with a parallel study, which investigates the consumption of Canarian local product by buffet restaurants in five and four stars hotels as well. This study is based on the investigation initiated by Gestión del Medio Rural Canarias, GMR from now on, which not only wants to know the level of knowledge people have about local production and the usage of it, but also to improve and promote the consumption of the local product. Finally, the investigation shows the results from which new ways to improve the consumption and awareness of the local products are offeredEn este estudio se lleva a cabo una investigación de los usos del producto local en los restaurantes de los establecimientos hoteleros de 4 y 5 estrellas de la isla de Tenerife. Así pues, esta investigación trata, de manera concreta, de establecer una comparativa entre los diferentes restaurantes a la carta sometidos a estudio, de ahora en adelante restaurantes, complementando de esta forma la investigación sobre el consumo de producto local en los diferentes establecimientos hoteleros de cuatro y cinco estrellas de la isla. De forma paralela, el estudio se basa en las motivaciones de la investigación iniciada por Gestión del Medio Rural Canarias, de aquí en adelante GMR, en la que se basa este trabajo, y que no solo busca conocer el nivel de conocimiento que se tiene acerca del producto local y el uso que se hace de él dentro de los establecimientos estudiados, sino también potenciar su consumo y encontrar nuevas formas de incentivarlo. Finalmente, se muestran los resultados a partir de los cuales se ofrecen nuevas formas de incentivar el consumo de los productos locales en los diferentes territorios sometidos a estudio

Impact of earthquakes on agriculture during the Roman–Byzantine period from pollen records of the Dead Sea laminated sediment

The Dead Sea region holds the archives of a complex relationship between an ever-changing nature and ancient civilisations. Regional pollen diagrams show a Roman–Byzantine period standing out in the recent millennia by its wetter climate that allowed intensive arboriculture. During that period, the Dead Sea formed laminites that display mostly a seasonal character. A multidisciplinary study focused on two earthquakes, 31 BC and AD 363, recorded as seismites in the Ze’elim gully A unit III which has been well dated by radiocarbon in a previous study. The sampling of the sediment was done at an annual resolution starting from a few years before and finishing a decade after each earthquake. A clear drop in agricultural indicators (especially Olea and cereals) is shown. These pollen indicators mostly reflect human activities in the Judean Hills and coastal oases. Agriculture was disturbed in large part of the rift valley where earthquake damage affected irrigation and access to the fields. It took 4 to 5 yr to resume agriculture to previous conditions. Earthquakes must be seen as contributors to factors damaging societies. If combined with other factors such as climatic aridification, disease epidemics and political upheaval, they may lead to civilisation collapse