>Magister Scientiae - MSc / In this study PbSe quantum dots (QDs) were successfully synthesized via the organometallic and aqueous routes. Optical characterization was carried out using photoluminescence (PL) spectroscopy, structural and morphological characterization were carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Energy-dispersive X-ray spectroscopy (EDS) was used to determine the composition of the QDs. All the synthesized QDs were found to have emissions within the near-infrared region of the spectrum (≥1000 nm) with most of them being less than 5 nm in size. The aqueous synthesized QDs had a perfect Gaussian emission spectrum with a FWHM of ~23 nm indicating pure band gap emission and narrow size distribution respectively. The QDs were determined to have a cubic rock-salt crystal structure consistent with bulk PbSe. The aqueous synthesized QDs were however not stable in solution with the QDs precipitating after approximately 48 h. The organometallic synthesized QDs were transferred into the aqueous phase by exchanging the surface oleic acid ligands with 11-mercaptoundecanoic acid ligands. The ligand exchanged QDs were however stable in solution for over two weeks. The effects of reaction parameters on the optical and structural properties of the organometallic synthesized QDs were investigated by varying the reaction time, temperature, ligand purity, lead and selenium sources. It was observed that larger QDs were formed with longer reaction times, with reactions proceeding faster at higher reaction temperatures than at lower temperatures. Varying the ligand purity was found to have minimal effects on the properties of the synthesized QDs. The lead and selenium sources contributed largely to the properties of the QDs with lead oxide producing spherical QDs which were smaller compared to the cubic QDs produced from lead acetate. TBPSe was seen to produce smaller QDs as compared to TOPSe. The cytotoxity of the synthesized QDs was determined following the WST-1 cell viability assay with the QDs being found to be non-toxic at all the tested concentrations

Este trabalho apresenta três sistemas de controle distintos para a atuação em sistemas de tração elétrica traseira em veículos de passeio convencionais convertidos em VEHs (Veículos Elétricos Híbridos) 4x4, enfocando o desenvolvimento de um sistema diferencial eletrônico (SDE). As principais arquiteturas de veículos híbridos são apresentadas. O SDE, que atua em tempo de execução nas velocidades angulares dos pneumáticos traseiros em manobras variadas, depende dos sinais de esterçamento e aceleração impostos pelo condutor, considerando as modelagens cinemática e dinâmica do veiculo no cálculo dos valores de referência para o controlador. Controladores PID modificado, neurofuzzy baseado em inteligência artificial e um H-Infinito ótimo são projetados e detalhados. Uma nova arquitetura para o SDE é proposta e apresentada, visando a utilização de sistemas de controle robustos no problema do SDE, traçando-se um paralelo entre o seu desempenho e das arquiteturas convencionais quando o controlador H-Infinito ótimo assume o controle do SDE. O projeto e o desenvolvimento de um mini-VEH, a plataforma HELVIS (Hybrid ELectric Vehicle In low Scale), são apresentados. A implementação de um simulador veicular denominado HELVIS-SIM, inspirado na plataforma HELVIS, é também apresentada. O SDE, que compreende a arquitetura proposta e os controladores, são embarcados e também implementados no HELVIS-SIM. Resultados simulados obtidos no HELVIS-SIM são analisados. Testes experimentais do SDE na plataforma HELVIS são apresentados, considerando apenas testes de bancada sem o contato dos pneumáticos com o solo. / This work presents the development of three distinct control systems to rear electric traction control on conventional touring vehicles converted on 4WD (four-wheel drive) hybrid electric vehicles (HEVs), focusing on the design of a EDS (Electronic Differential System). Main HEV architectures are presented. The EDS controls the rear wheels angular speeds as the driver inputs steering and acceleration commands, considering both dynamic and kinematic models of the vehicle and so the actuators on the calculus of the desired rear angular speeds. One modied PID controller, one AI (Articial Intelligence) based controller and one robust optimal H \'infinite\' controller are designed and outlined. A new EDS architecture is proposed and presented, aimming the use of robust controllers to the EDS problem, comparing the use of the H \'infinite\' optimal controller to conventional EDS architectures. The design of a mini-HEV, the HELVIS (Hybrid ELectric Vehicle In low Scale) platform is also presented. The implementation of a parametric vehicular simulator, the HELVIS-SIM, is discussed. The EDS, which represents the controllers and the proposed architecture, is evaluated on the HELVIS platform and on the HELVIS-SIM. Simulated results are rst run in the HELVIS-SIM. Experimental results of the EDS tests are presented exclusively considering the evaluation on a bench test, without any contact of the platform with the pavement.

Las Percepciones de las Capacidades para la Gestión de la Sostenibilidad del Estudiantado del Grado de ADE de la UPV y la UCV: Análisis Comparado. El propósito de la investigación doctoral es comprender las percepciones y predecir los comportamientos como gestor de Sostenibilidad del estudiantado de Administración y Dirección de Empresas de dos universidades: Universidad Politécnica de Valencia y Universidad Católica de Valencia. Para ello, los objetivos que la vertebran son: 1) Argumentar críticamente una Teoría que, además de ser aceptada por la comunidad científica, sea potente para la comprensión y el aprendizaje de la Gestión de la Sostenibilidad; 2) Seleccionar una Teoría psicosocial, aceptada por la comunidad científica, para comprender y predecir el comportamiento del estudiantado hacia la Gestión de la Sostenibilidad; 3) Construir un cuestionario-escala, a partir de la Teoría seleccionada, siguiendo los procedimientos establecidos por la comunidad de los científicos sociales; 4) Analizar, comentar y discutir los resultados de las respuestas dadas por la población objeto de la investigación; 5) Comparar los resultados obtenidos entre las diversas poblaciones investigadas y establecer semejanzas y diferencias sobre la Gestión de la Sostenibilidad. Las hipótesis son las siguientes: 1) El estudiantado de ambas Universidades es mayoritariamente favorable al aprendizaje de la Gestión de la Sostenibilidad en todos los elementos que configuran las percepciones; 2) Las mujeres muestran percepciones significativamente más positivas que los varones respecto a la Gestión de la Sostenibilidad; 3) Existen diferencias en las percepciones para la Gestión de la Sostenibilidad entre el alumnado de la Universidad Católica de Valencia y el de la Universidad Politécnica de Valencia. Para alcanzar los objetivos propuestos, el proceso de investigación ha cumplimentado las siguientes fases: a)la argumentación de la importancia del problema que se investiga a la que se ha dedicado el capítulo 2º; b)la revisión del estado actual del conocimiento sobre el problema investigado; a ello se ha dedicado el capítulo 1º; c) la justificación de la perspectiva teórica que se adopta,el enfoque del Desarrollo de las Capacidades Humanas,a la que se dedica el capítulo 3º; d) la selección argumentada de la Teoría dela Acción Planificada de Azjen, en el capítulo 4º; e) la presentación crítica de la metodología de la investigación, en el capítulo 5º, que utiliza de forma complementaria la perspectiva empírico-analítica, que permite explicar y predecir el comportamiento del estudiantado; la hermenéutico-interpretativa, que facilita la comprensión de los significados de las intenciones y acciones del alumnado y el método comparado entre el alumnado de una Universidad y la otra; f) la aplicación del cuestionario-escala, análisis de los datos y comentarios de los resultados de las respuestas del alumnado de la Universidad Católica de Valencia (capítulo 6º), del alumnado de la Universidad Politécnica de Valencia (capítulo 7º) y de la comparación entre el alumnado de ambas universidades (capítulo 8ª). Conclusiones: a)la hipótesis 1. El estudiantado de ambas Universidades es mayoritariamente favorable al aprendizaje de la Gestión de la Sostenibilidad en todos los elementos del sistema de actitudes. La hipótesis 1 queda confirmada en 5 de las 8 sub-hipótesis y parcialmente confirmada en las tres restantes; b) la hipótesis 2. Las mujeres muestran un sistema de actitudes significativamente más positivas que los varones respecto a la Gestión de la Sostenibilidad. La hipótesis 2 queda confirmada; c) la hipótesis 3. Existen diferencias en el sistema de actitudes para la Gestión de la Sostenibilidad entre el alumnado de la Universidad Católica de Valencia y el alumnado de la Universidad Politécnica de Valencia. La hipótesis 3 queda confirmada en 7 de sus 9 sub-hipótesis, parcialmente c / Les Percepcions de les Capacitats per a la Gestió de la Sostenibilitat de l'Estudiantat del Grau d'ADE de la UPV i la UCV: Anàlisi Comparada. El propòsit de la investigació doctoral és comprendre les percepcions i predir els comportaments com a gestor de Sostenibilitat de l'estudiantat d'Administració i Direcció d'Empreses de dues universitats: Universitat Politècnica de València i Universitat Catòlica de València. Per a això, els objectius que la vertebren són: 1) Argumentar críticament una Teoria que, a més de ser acceptada per la comunitat científica, siga potent per a la comprensió i l'aprenentatge de la Gestió de la Sostenibilitat; 2) Seleccionar una Teoria psicosocial, acceptada per la comunitat científica, per a comprendre i predir el comportament de l'estudiantat cap a la Gestió de la Sostenibilitat; 3) Construir un qüestionari-escala, a partir de la Teoria seleccionada, seguint els procediments establerts per la comunitat dels científics socials; 4) Analitzar, comentar i discutir els resultats de les respostes donades per la població objecte de la investigació; 5) Comparar els resultats obtinguts entre les diverses poblacions investigades i establir semblances i diferències sobre la Gestió de la Sostenibilitat. Les hipòtesis són les següents: 1) L'estudiantat d'ambdues Universitats és majoritàriament favorable a l'aprenentatge de la Gestió de la Sostenibilitat en tots els elements que configuren les percepcions; 2) Les dones mostren percepcions significativament més positives que els homes respecte a la Gestió de la Sostenibilitat; 3) Existeixen diferències en les percepcions per a la Gestió de la Sostenibilitat entre l'alumnat de la Universitat Catòlica de València i el de la Universitat Politècnica de València. Per a aconseguir els objectius proposats, el procés d'investigació ha cobert les següents fases: a) l'argumentació de la importància del problema que s'investiga a la que s'ha dedicat el capítol 2n; b) la revisió de l'estat actual del coneixement sobre el problema investigat; a això s'ha dedicat el capítol 1r; c) la justificació de la perspectiva teòrica que s'adopta, l'enfocament del Desenvolupament de les Capacitats Humanes, a la qual es dedica el capítol 3r; d) la selecció argumentada de la Teoria de l'Acció Planificada d'Azjen, en el capítol 4rt; e) la presentació crítica de la metodologia de la investigació, en el capítol 5é, que utilitza de forma complementària la perspectiva empíric-analítica, que permet explicar i predir el comportament de l'estudiantat; l'hermenèutica-interpretativa, que facilita la comprensió dels significats de les intencions i accions de l'alumnat i el mètode comparat entre l'alumnat d'una Universitat i l'altra; f) l'aplicació del qüestionari-escala, anàlisi de les dades i comentaris dels resultats de les respostes de l'alumnat de la Universitat Catòlica de València (capítol 6é), de l'alumnat de la Universitat Politècnica de València (capítol 7é) i de la comparació entre l'alumnat d'ambdues universitats (capítol 8a). Conclusions: a) la hipòtesi 1. L'estudiantat d'ambdues Universitats és majoritàriament favorable a l'aprenentatge de la Gestió de la Sostenibilitat en tots els elements del sistema d'actituds. La hipòtesi 1 queda confirmada en 5 de les 8 sub-hipòtesis i parcialment confirmada en les tres restants; b) la hipòtesi 2. Les dones mostren un sistema d'actituds significativament més positives que els homes respecte a la Gestió de la Sostenibilitat. La hipòtesi 2 queda confirmada; c) la hipòtesi 3. Existeixen diferències en el sistema d'actituds per a la Gestió de la Sostenibilitat entre l'alumnat de la Universitat Catòlica de València i l'alumnat de la Universitat Politècnica de València. La hipòtesi 3 queda confirmada en 7 de les seues 9 sub-hipòtesis, parcialment confirmada en 1 sub-hipòtesi i no confirmada en 1 sub-hipòtesi. / Perceptions of the Capacities for Sustainable Management in the Students of "Administration and Business Management" Degree in the Polytechnic University of Valencia and the Catholic University of Valencia: A Comparative Analysis. The purpose of the doctoral research is to understand perceptions and to predict behaviors as Sustainable managers in Administration and Business Management students of two universities: the Polytechnic University of Valencia and the Catholic University of Valencia. To this end, the objectives that underpin are: 1) Critically argue a theory that, in addition to being accepted by the scientific community, is powerful for understanding and learning Sustainability Management; 2) Select a psychosocial theory, accepted by the scientific community, to understand and to predict behavior students towards Sustainability Management; 3) Construct a questionnaire-scale, based on the selected theory, following the procedures established by the community of social scientists; 4) Analyze, comment and discuss the results of the answers given by the population under investigation; 5) Compare the results obtained among different researched populations and establish similarities and differences on Sustainability Management. The hypotheses are: 1) Students of both Universities are mainly favorable to learning Sustainability Management in all the elements that configure the perceptions; 2) Women express significantly more positive perceptions than men with respect to Sustainability Management; 3) There are different perceptions of Sustainability Management among the students in the Catholic University of Valencia and in the Polytechnic University of Valencia. In order to achieve the stipulated objectives, the research process has completed the following phases: a) argumenting the importance of the problem under investigation which is adressed in the 2nd chapter ; b) elaborating the current literature review about the issue under investigation; which is adressed in the 1st chapter; c) justificating the theoretical perspective that is adopted: Development of Human Capacities approach; which is adressed in the 3rd chapter; d) Arguing the selection of Azjen's Theory of Planned Behavior, in the 4th chapter; e) critically presentating the research methodology, in the 5th chapter, which uses in a complementary way the empirical-analytical perspective, which allows explaining and predicting student behavior; the hermeneutic-interpretative perspective, which facilitates understanding the meanings of the intentions and actions in the students and the comparative method between the students at one university and at the other; f) applicating the questionnaire-scale, analysing the data and commenting on the results of the responses of the students at Catholic University of Valencia (6th chapter), the students at Polytechnic University of Valencia (7th chapter) and the comparison between the students of both universities (8th chapter). Conclusions: a) hypothesis 1. The students of both Universities are mostly favorable for learning Sustainability Management in all of the elements of the attitude system. Hypothesis 1 is confirmed in 5 of the 8 sub-hypotheses and partially confirmed in the remaining three; b) hypothesis 2. Women show a system of significantly more positive attitudes than men with respect to Sustainability Management. Hypothesis 2 is confirmed; c) hypothesis 3. There are differences in the attitude system for Sustainability Management among the students of the Catholic University of Valencia and the students of the Polytechnic University of Valencia. Hypothesis 3 is confirmed in 7 of its 9 sub-hypotheses, partially confirmed in 1 sub-hypothesis and not confirmed in 1 sub-hypothesis. / Escámez Marsilla, JI. (2018). LAS PERCEPCIONES DE LAS CAPACIDADES PARA LA GESTIÓN DE LA SOSTENIBILIDAD DEL ESTUDIANTADO DEL GRADO DE ADE DE LA UPV Y LA UCV: ANÁLISIS COMPARADO [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/115487 / TESIS

This diploma thesis deals with various procedures of surface pretreatment of steel and aluminum alloy for subsequent application of powder coating substance. The work begins with an overview of the general characteristics of the materials used. The core part of the work is then a summary of the individual methods of pretreatment that can be used to modify the material surface. A special chapter is devoted to methodologies for the application of powder substances. Before separate application, the sample must first be carefully pretreated to ensure removal of organic compounds (e.g. oils from primary processing - grinding, cutting), or dust impurities to ensure the correct barrier effect. After dividing the individual methods of surface preparation, a powder paint system with a total thickness of approximately 50 µm is applied to the test material. Samples with different surface pretreatments will be compared both in terms of mechanical properties and in terms of electrochemical properties.

This thesis presents results of the corrosion layers removal which could be found on the archaeological artefact surfaces. The low pressure low temperature plasma reduction was used for this purpose. Brass samples were chosen for this study. Two different ways have been used to form model corrosion layers. Several sets of corrosion layers were prepared in laboratory in two different corrosion atmospheres, namely ammonia atmosphere and atmosphere of hydrochloric acid. These samples were placed into desiccator. Small quantities of sand were added to some sets of samples so samples with sandy incrustation were prepared. The corrosion layers had been usually formed during four weeks. The second way, which was used to prepare model corrosion layer, was the natural corrosion in soil or compost. In this case, the corrosion layers had been formed approximately 2 years. The samples were treated in the low pressure (150 Pa) cylindrical Quartz reactor (90 cm long and 9.5 cm in diameter) with a pair of external copper electrodes connected via the matching network to a radiofrequency generator (13.56 MHz). The flows of working gases were set by independent mass flow controllers. Whole system was continuously pumped by the rotary oil pump which was separated from the discharge reactor by liquid nitrogen trap with aluminium chips eliminating dust and reactive species from the gas flow. Each sample was placed on a glass holder at the reactor center. Plasma was generated in pure hydrogen or in mixture of hydrogen and argon. Total flow of working gas was 50 sccm. Different ratios of gas mixture were tested, the ratio 30 sccm hydrogen and 20 sccm argon flows was the best. RF discharge was used in a continuous and pulsed regime. Pulsed mode was carried out with various duty cycle at the frequency of 1000 Hz. There were two ways of temperature monitoring. The sample temperature during the treatment was monitored by a K-type thermocouple installed inside the sample in the first case. Thermometer optical probe was connected to the sample surface by a small stainless plate and allowed continuous sample temperature monitoring in the second way. Safe object temperature for copper and copper alloys is 100–120 °C. To avoid exceeding this temperature, power control or the duty cycle in pulse mode were automatically controlled if thermometer optical probe was used. Plasma chemical treatment is based on generation of reactive atomic hydrogen in plasma discharge. The main reactions during reduction were reactions between oxygen and chloride contained in the corrosion layer and the hydrogen ions and neutral atoms generated in the plasma. These reactions create an unstable OH radical, which emits light in the region of 306–312 nm. This radiation was detected by the optical emission spectroscopy using Ocean Optics HR4000 spectrometer with 2400 gr/mm grating. Data obtained from this method were used to calculate rotational temperatures and integral intensity of OH radicals that were used for the process monitoring. Corrosion layer was not completely removed during the reduction, but due to the reactions which occur in the plasma corrosion layer became brittle and after plasma chemical treatment can be removed easily. The SEM-EDS material analyses were carried out before and after treatment of some samples. Some samples were analysed by XRD analysis. EDS analysis showed that amount of oxygen and chloride was decreased, mainly at 400 W pulse mode.

A compositionally graded Ti-xCr (10≤x≤30 wt%) alloy has been fabricated using Laser Engineered Net Shaping (LENSTM) to study the microstructural phase evolution along a compositional gradient in both as-deposited and heat treated conditions (1000°C followed by furnace cooling or air cooling). The alloys were characterized by SEM BSE imaging, XRD, EBSD, TEM and micro-hardness measurements to determine processing-structure-property relations. For the as-deposited alloy, α-Ti, β-Ti, and TiCr2 (C15 Laves) phases exist in varying phase fractions, which were influential in determining hardness values. With the furnace cooled alloy, there was more homogeneous nucleation of α phase throughout the sample with a larger phase fraction of TiCr2 resulting in increased hardness values. When compared to the air cooled alloy, there was absence of wide scale nucleation of α phase and formation of ω phase within the β phase due to the quicker cooling from elevated temperature. At lower concentrations of Cr, the kinetics resulted in a diffusionless phase transformation of ω phase with increased hardness and a lower phase fraction of TiCr2. In contrast at higher Cr concentrations, α phase separation reaction occurs where the β phase is spinodally decomposed to Cr solute-lean β1 and solute-rich β2 resulting in reduced hardness.

According to the 2019 Canadian infrastructure report card, a concerning amount of municipal infrastructure is in poor or very poor condition. The infrastructure in this condition requires immediate action for rehabilitation or replacement. For concrete infrastructure, an effective repair can extend its service life and ensure that the services it provides continue to meet the community expectations. However, unfavorable environmental factors such as repeated/cyclic loads and freezing and thawing cycles adversely affect the bond between substrate concrete and repair materials, which lowers the structural capacity of repaired structures. So far, researchers have found that bond strength of repair can be affected by surface roughness, surface moisture, chemical adhesion or cohesion, curing regime, properties of substrate and repair materials, use of bond agent, and curing regimes. These findings are mostly based on the studies that focused on cold-jointed cylinders or beams, but in real-life repair situations, repairs of beams or slabs are located at either tension or compression side of the structure. Currently, there is no comprehensive study that investigates the bond of concrete repair under a combination of freezing and thawing and repeated/cyclic loading conditions. In addition, it is challenging to provide a rapid and non-destructive evaluation of the bond deterioration of repair materials. To address these issues systematically, this dissertation breaks the task into four phases. Phase (I) focuses on the development of an engineered “crack-free” repair mix that contains polypropylene (PP) fiber. A novel method is used to surface treat the PP fibers with supplementary cementitious materials. The effectiveness of surface-treating fibers for improved bond strength and reduced cracking is investigated. The compressive, tensile, and flexural strength of this engineered repair mix are determined and compared with two commercially available repair materials. The results from Phase I show that by adding 0.2% (by weight) Metakaolin-treated fibers into concrete mix, the compressive strength improves by up to 15.7% compared to mixes with untreated fibers. This study achieved a strength increase of 13.5% as compared to the reported 3.3% in other studies that use 25 times the amount of metakaolin used in this study. The experimental results confirm that at 0.2% dosage level, the use of novel surface treating technique is a cost-effective way to improve the strength of repair materials. Phase (II) focuses on characterizing the bond strength of various repair systems after freezing-thawing (FT) damage using both non-destructive and destructive methods. Two innovative sounding methods, which overcome the subjectivity of the traditional chain drag method, are used to evaluate FT damage non-destructively. In the experimental study, beams with a U-shaped cut are made to simulate conditions experienced by a concrete structure during a typical repair project. Three types of repair materials are used including cementitious repair concrete, cementitious repair mortar, and polymer-modified cementitious mortar. After up to 300 cycles of freeze-thaw exposure, resonant frequency and bond flexural strength of the prismatic specimens are determined. The empirical equations relating Non-destructive test (NDT) measurements and flexural bond strength of the repaired structures after freeze-thaw (FT) exposure are proposed. The results from Phase II show that the change in dynamic modulus of elasticity determined from NDTs agrees well with the change in other measurements including flexural bond strength, interfacial crack width, and mass loss after freeze-thaw exposure. In this study, linear relationships are established between dynamic modulus of elasticity and flexural bond strength for both cementitious and polymer-modified cementitious repair mortar with a coefficient of determination ranging between 0.87 and 0.95. The proposed empirical models can be used to predict bond flexural strength of repaired structures based on NDT measurement. Also, it was found that the samples repaired with polymer-modified cementitious mortar (Mix P) have superior FT resistance compared to other repaired samples. Phase (III) focuses on investigating the structural capacity and bond performance of repaired beams after cyclic/repeated loading. To accelerate the test process, a novel modified loading regime consisting of cycle groups of increasing cyclic/repeated stress amplitude is proposed. The models proposed by literature and current codes and standards are used to validate the results. Phase (IV) focuses on the development of the damage models for both individual and combined FT and cyclic loading exposure on repaired concrete structures. The results in phase III show the feasibility of using the Palmgren-Miner rule and Goodman linear model to estimate the fatigue life of repaired structures. This was confirmed within the context of this study. This study established the usefulness of using groups of increasing cyclic stress amplitude to accelerate the fatigue test process. The two-million cycle fatigue endurance limit estimated using cycle groups of Mix S (70.8%) was very similar to what was reported in the literature (71%) using the traditional time-consuming cyclic loading method. This study found that the formulas proposed by CSA 23.3 can effectively predict the moment resistance of both intact (control) and repaired RC beams. The ratio of experimental moment resistance values to its predictions ranges from 0.91 to 1.04. Based on the experimental results of previous three phases, an empirical model that predicted the fatigue service life of FT-damaged concrete structures is proposed. Future research requires a more comprehensive study on the FT performance of various polymer-modified cementitious mortars of different mix designs in repairing concrete structures. By increasing the number of tested specimens, a better relationship could be established between destructive and NDT methods. Future research is also required to explore the combined effect of FT and cyclic loading on repaired RC structures experimentally. / Graduate / 2023-03-22

No description available.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Provisional restorative treatment is an essential part of fixed prosthodontics. Incorporation of adequately constructed provisional restorations will enhance the success rate of definitive restorations. Repairing or replacing failed provisional restorations is a concern for both clinicians and patients. The objective of this investigation was to study the effects of alumina nanofibers reinforcement on the mechanical properties of commercially available provisional fixed partial denture PMMA material. The hypothesis was that the addition of alumina nanofibers to commercially available PMMA resin will significantly increase its flexural strength, fracture toughness, and microhardness. Alumina nanofibers at 0.0 wt %, 0.5 wt %, 1.0 wt %, and 2.5 wt % were added to commercially available provisional fixed partial material (Jet Tooth Shade). A quaternary ammonium acetate dispersant (CC-59, Goldschmidt, Janesville, WI) was added to the acrylic monomer at 0.0 wt %, 1.0 wt %, 2.0 wt % and 5.0 wt % of the nanofiber weight (12 test groups, 1 control). Samples from each group were evaluated for flexural strength, flexural modulus, fracture toughness, and microhardness. The samples were tested after storing in distilled water for 24 hours and 7 days at 37ºC. Two-way analysis of variance (ANOVA) was used to test the effects of storage time and combinations of alumina nanofiber level and quaternary ammonium acetate dispersant level on the flexural strength, fracture toughness, and microhardness of the provisional PMMA resin. Pair-wise comparisons between groups were performed using Tukey’s multiple comparisons procedure to control the overall significance level at 5 percent. Three fracture toughness samples/group were randomly selected for Energy Dispersive Spectrometry (EDS) to qualitatively evaluate the dispersion of the fibers. The data obtained from this study showed that control sample values were in the acceptance range compared with previous research. The experimental samples did not reinforce the provisional resin in the flexural strength, modulus, fracture toughness, or microhardness. There are several factors may attribute to these results, such as poor bonding at the filler/matrix interface. The more homogeneous the mixture of PMMA and fiber, the stronger the acrylic resin. In fact, the presence of poorly bonded fibers, to which little load is transferred, can be almost equivalent to voids. In addition, as seen with EDS images, alumina nanofibers had a tendency to agglomerate. The use of a magnetic stirrer was not effective in physically separating nanofibers agglomerates. Direct dispersion of alumina nanofibers in methyl methacrylate monomer and quaternary ammonium acetate dispersant was not effective in separating the nanofibers into nano-scaled single crystals. The presence of fiber agglomerates acts as a structural defect that detrimentally affects the mechanical properties. Further studies are needed to evaluate the effectiveness of fibers, dispersion techniques, and coupling agents to enhance the mechanical properties of the provisional PMMA resin.