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In the field of optical fiber sensors, one of the most versatile structures is the Fabry-Perot interferometer. This thesis will present a novel sensor based on an Intrisnic Fabry-Perot Inferferometer (IFPI) cavity to measure axial acceleration, refractive index, and temperature. The sensor structure is based on previous work done by R. Wang at the Center for Photonics Technology. This work suggests its flexibility in many different roles with a sensitivity to axial acceleration of 70 pm/unit of acceleration, to refractive index of 60 nm/Refractive Index Unit, and to temperature of 7.8 pm/°C. Future work is also discussed in measuring tangential acceleration with direction using a PM fiber as the lead-in and observing the reflections on the slow and fast axes. / Master of Science

A method was developed to produce and incorporate a network of discrete, genipin-crosslinked gelatin microfibers around a pancreatic islet within a barium alginate microcapsule. This technique allows for the encapsulation of a porous fibrous matrix without the geometrical restrictions required for cellular aggregate seeding. Microfibers were produced from a novel vortex-drawn extrusion system with an alginate support matrix. Optimization culminated in a hydrated fiber diameter of 22.3 ± 0.4 μm, a 98% reduction in cross sectional area, while making the process more reliable and less labour intensive. The optimized microfibers were encapsulated at 40 vol% within 294 ± 4 μm 1.6% barium alginate microparticles by an electrostatic-mediated dropwise extrusion system. Pancreatic islets extracted from Sprague Dawley rats were encapsulated within the microparticles, and analyzed over a 21-day preliminary in vitro study. Acridine orange and propidium iodide fluorescent viability staining and light microscopy indicated a significant increase in viability for the fiber-laden particles relative to fiber-free control particles at days 7, 14, and 21. The fiber-laden system also reduced the incidence of disrupted islet cohesion from 31% to 8% at day 21, and showed evidence of islet-fiber adhesion. Preliminary investigations into insulin secretion and metabolic activity showed no significant difference between test and control groups. Further investigation into benefits of islet encapsulation within an extracellular matrix fiber network will be the subject of future studies with this body of work serving as a foundation. The system developed in this investigation could be developed into a modular scaffold system for tissue engineering beyond the field of islet research. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-08-18 15:05:50.917

Contaminated environmental surfaces can be a means of transmission of Clostridium difficile spores in health-care facilities. The study objectives are to assess the value of the UV marker as an audit tool for improving housekeeping compliance and to compare microfiber and cotton cloths for removal of Clostridium difficile spores from surfaces. A lotion visible only under short-wave UV light (UV Marker) was applied to different surfaces within the patient’s washrooms on consecutive week days, over a twenty-four week period. The Study included three Arms: Arm one received feedback for 24 weeks , Arm two received feedback for the first 12 weeks and Arm three was given feedback for the last 12 weeks based on UV Marker results. The visual audit resulted in a cleaning compliance of 55%; whereas, feedback with the UV Marker led to a housekeeping compliance of 90%. The UV marker is a better audit tool than visual inspection for improving cleaning compliance of housekeeping staff. The use of microfiber cloths may enhance efficiency of microbial removal during surface cleaning.

Contaminated environmental surfaces can be a means of transmission of Clostridium difficile spores in health-care facilities. The study objectives are to assess the value of the UV marker as an audit tool for improving housekeeping compliance and to compare microfiber and cotton cloths for removal of Clostridium difficile spores from surfaces. A lotion visible only under short-wave UV light (UV Marker) was applied to different surfaces within the patient’s washrooms on consecutive week days, over a twenty-four week period. The Study included three Arms: Arm one received feedback for 24 weeks , Arm two received feedback for the first 12 weeks and Arm three was given feedback for the last 12 weeks based on UV Marker results. The visual audit resulted in a cleaning compliance of 55%; whereas, feedback with the UV Marker led to a housekeeping compliance of 90%. The UV marker is a better audit tool than visual inspection for improving cleaning compliance of housekeeping staff. The use of microfiber cloths may enhance efficiency of microbial removal during surface cleaning.

Meniscus is a fibrocartilaginous tissue which plays an important role in joint stability, lubrication, and load bearing and transmission. Meniscal tears are commonly encountered in sports activities, or caused by degeneration of the cartilage with ageing. They lead to pain, loss of work, disturbed biomechanics of the knee and inability to walk or even move the legs. As the meniscal tissue is avascular in the inner portion, injury to this part does not heal by itself, and therefore treatments are needed. In some cases when complex tears occur, the tissue cannot be successfully treated with the conventional methods. Tissue engineering appears to be a promising alternative to treat such complex tears. It includes the application of cells on scaffolds (or cell carriers), and provision of bioactive agents to the site of injury in order to regenerate the damaged tissue. The cells and the bioactive agents are involved in the synthesis of the new tissue, while the scaffold acts as a support to guide the cells until the new tissue is formed, and it is slowly absorbed by the body leaving the new tissue behind. Thus, a natural tissue is generated at the end. Few studies have been reported on the tissue engineering of meniscus, but neither of them was able to completely mimic the meniscus structure, nor could they succeed in constructing scaffolds with sufficiently high tensile properties. In the current in vitro study, a novel 3D construct was proposed, in which the natural tissue is perfectly mimicked. The 3D construct consisted of aligned collagen fibers embedded within a foam network which stabilizes the structure. The foam was prepared by freezing a polymer solution with a certain concentration, and lyophilizing it. Aligned fibers were aimed to improve the tensile properties. The construct was impregnated in alginate gel, which was then crosslinked, to improve the compressive properties. The foam was prepared from (poly(L-lactic acid)/poly(lactic-co-glycolic acid) (PLLA/PLGA) solutions of various concentrations (2%, 2.5%, 3%, and 4% w/v) and at different freezing temperatures (-20oC or -80oC) to select the best preparation condition. After analysis of the microstructure and mechanical properties, foams prepared from 3% polymer solution frozen at -20oC were found to be the most appropriate for use as scaffold for the 3D construct, since they had large pores, high and interconnected porosity, as well as high mechanical strength. The 3D constructs were seeded with human meniscus cells and incubated for 21 days. Cell behavior on the constructs was examined. Cell attachment and proliferation was found to be better with the constructs not coated with alginate. However, the constructs coated with alginate demonstrated higher compressive strength. It was also found that incorporation of collagen fibers significantly improved the tensile properties. All the constructs were shown to lead to the production of extracellular components specific for fibrocartilages, and thus it was concluded that they were promising for use in meniscal replacement.

La presente investigación buscara la dosificación optima de microfibra para controlar la retracción plástica comparando microfibras sintéticas de polipropileno FIBRA ULTRAFINA de la marca CHEMA y microfibra sintética acrílica DRYMIX RC4020 de la marca SUDAMERICANA DE FIBRAS, considerando las dosificaciones que recomiendan los proveedores por cada metro cubico de concreto. Se realizarán ensayos de laboratorio en 17 mezclas para luego medir la retracción plástica en cada una de ellas utilizando los paneles normados por el ASTM C1579-13, midiendo también las demás propiedades que serán comparadas con el desempeño de un concreto convencional. El resultado de esta investigación será el valor de dosificación óptima con la que se logre disminuir la retracción plástica sin afectar otras propiedades del concreto, tales como resistencia a la compresión, tracción, flexión y trabajabilidad. De igual manera se realizará un análisis económico de acuerdo con las dosificaciones realizadas de las fibras anteriormente mencionadas. / The present investigation will search the optimal dosage from microfiber to control the plastic shrinkage comparing the polypropylene synthetic microfiber Fibra Ultrafina by the brand CHEMA and the acrylic synthetic microfiber Drymix RC4020 by the brand SUDAMERICANA DE FIBRAS, considering the dosages per cubic meter that the providers recommend. It will perform laboratory tests in 17 mixes by then measure the plastic shrinkage in each of them using the standardized panels by the ASTM C1579-13, also will measure the other properties that will be compared with the performance from a conventional concrete. The investigation result will be the optimal dosage valor that can reduce the plastic shrinkage without affecting the other concrete properties like the compressive strength, tensile strength, flexural strength and slump. Likewise, it will perform an economic analysis according the fiber dosages aforementioned. / Tesis

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I arbetet för Vikan AB var uppgiften att undersöka två olika delningsmetoder för mikrofibrer. Vikan AB är ett företag som utvecklar och framställer textila rengöringsredskap i mikrofibrer och tror sig ha kommit på en ny delningsmetod som förhoppningsvis ger en rad fördelar mot den nuvarande metoden. Den nya framställningsmetoden går under arbetsnamnet Easy Split och har ännu inte introducerats på marknaden.Studien har gått ut på att i fyra olika avseenden utvärdera de olika metodernas för- och nackdelar. De olika aspekterna har således varit processgång, utseende, hållbarhet och funktion. Utvärderingen utfördes med hjälp av en rad undersökningar där bland annat tester i absorption, kvadratmetervikt och fläckreduktion ingick.Många av egenskaperna undersöktes med hjälp av befintliga standarder medan undersökningen av fläckreduktionen skedde med en egenutvecklad testmetod. Till denna metod användes en Martindale vars rörelsemönster och tryck är valdes utifrån att göra testmetoden så verklighetstrogen som möjligt. Resultaten visar att det finns en skillnad på de olika metoderna och att de önskvärda egenskaperna finns starkast representerade hos den Easy split- baserade mikrofiberdelningen. De besparingar Vikan kan göra i och med att byta delningsmetod kan ha inverkan på energi- och vattenförbrukningen vilket resulterar i tidsbesparingar och minskade kostnader. / <p>In collaboration with Vikan AB the task has been to examine the different splitting types for microfibers. The company Vikan AB develops and produces textile cleaning products in microfibers and they now seem to have come up with a new splitting method that hopefully will give a range of advantages compared to the present method. The new method goes under the name Easy split and has not yet been introduced to the market.The study consisted of an analysis of the pros and cons of the methods in four different aspects. The different points of view were processing, appearance, durability and function. The investigation was made with a variety of tests including absorption, weight per square meter and stain reduction. Many of the properties were examined with help of existing standard tests while the stain reduction was analyzed with a method developed for this specific purpose. To represent the real environment a Martindale was used because of its uniform moving pattern. The conclusion indicates that the new splitting method not only results in advantages in adsorption, weight and stain reduction but also in water and energy consumption as well as time and expenses.</p><p>Program: Textilingenjörsutbildningen</p>