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<p>The development of all-electric or plug-in hybrid vehicles requires the use of advanced energy storage devices with high power. Dedicated for energy storage, electrochemical supercapacitors (ES) offer the advantage of high power density. High power ES can provide load-leveling for batteries and fuel cells during starting, acceleration, hill climbing and braking. ES are important for reducing cycling of batteries, thus extending their lifetime by energy storage and delivery during fast transient operations such as in braking (storage) or start up and acceleration (supply).</p> <p>The interest in polypyrrole (PPY) for the application in ES is attributed to the high specific capacitance (SC) of this material. The possibility of PPY deposition on stainless steel substrates is important for the practical applications of PPY films in ES, using low cost stainless steel current collectors. The important task is to avoid anodic dissolution of the substrates during PPY electropolymerization. Polypyrrole (PPY) films were electrochemically deposited on stainless steel substrates or Ni plaque from aqueous pyrrole solutions containing anionic additives. The method resulted in the formation of adherent and uniform films. The deposition yield was investigated at galvanostatic conditions. It was found that anionic additives can be used for the dispersion of multiwall carbon nanotubes (MWCNTs) and fabrication of composite PPY–MWCNT films. The deposition yield was studied under galvanostatic conditions. The mechanism of PPY–MWCNTs deposition was discussed. The incorporation of MWCNTs into the PPY during electropolymerization resulted in the formation of porous films. The films were investigated for the application in electrodes of electrochemical supercapacitors. Electrochemical testing in the 0.5M Na₂SO₄ electrolyte solutions showed a capacitive behaviour in a voltage window of -0.5 to +0.4 V versus a saturated calomel electrode. The results indicated that the PPY–MWCNT films deposited on the stainless steel and nickel plaque substrates are promising electrode materials for ES.</p> / Master of Applied Science (MASc)

The purpose of this study was to investigate the effects of verbal-only and paired verbal-gestural instruction on the performance skills of wind instrumentalists with no more than three years of performance experience. Reviewed are different conducting strategies and their effects on musical expression in ensemble performance as demonstrated by small ensembles. Two sets of participants were used in this study. Audio stimulus files were derived from performances generated by the first set of participants, student musicians, who were randomly assigned to one of the two instruction groups. The primary sample consisted of students (n=30) from one intact public junior high school band. The second set of participants consisted of university undergraduate and graduate music majors (n=40) who evaluated the audio stimulus files. The first set of participants, middle school student musicians, who were randomly assigned to one of ten performance trios; trios were randomly assigned to one of two teaching conditions: (1) verbal-only, or (2) paired verbal-gestural. Students in each trio were assigned to perform Part 1, 2, or 3 of a two-minute performance selection that had been arranged purposefully to take into account participants’ performance level. Student participants performed this selection during a rehearsal in their assigned teaching condition. The student-investigator was the conductor/teacher in each condition. Rehearsals, consisting of sight-reading the work, investigator-led rehearsal, and final performance, were audio recorded for subsequent evaluation. Evaluators, undergraduate and graduate instrumental music majors (n=40) from a large research institution in the northeast United States, listened to the recordings and evaluated each rehearsal using a Continuous Response Digital Interface (CRDI) using the following criteria: musicality (phrasing, dynamics, balance, and expression) and technical accuracy (rhythm, articulation, intonation, and tempo). A paired-samples t-test was used to compare pretest (performance before rehearsal) and posttest (performance after rehearsal) outcomes. Aggregate data were analyzed using analysis of variance (ANOVA) comparing performance ratings among the three variables (rehearsal style, music mode, and grade). All Pairs Tukey-Kramer was used to show differences among groups and performances. Analyses indicated that this sample of middle school instrumentalists was significantly successful at their performance of two different variations (musicality and technical accuracy) after a rehearsal (posttest) in both verbal-only and verbal-gestural conditions than their first performance before a rehearsal (pretest). Pretest and posttest scores of the verbal-gestural group were higher than that of the verbal-only group, but rehearsal in the verbal-only condition showed more significant effectiveness in their development than under verbal-gestural conditions. Instrumentalists’ technical accuracy was rated as higher compared to musicality ratings in both pre- and posttests. Eighth grade players received higher scores on pre- and posttest in both verbal-only and verbal-gestural conditions than that of seventh grade players which might be expected since these players had more experience. Both verbal-only and verbal-gestural instruction conditions have similar effectiveness on student performance ratings, and based on the evidence derived from this study, it seems that both verbal and nonverbal instructional methods should be considered equally effective music teaching tools in an instrumental setting for students at this level of development. These findings should be taken into account when instrumental music educators are planning and delivering instruction, particularly in light of data showing that verbal instruction is more frequently used during rehearsals than nonverbal instruction. / Music Education

MnO2 continues to gain traction in the research and development of advanced supercapacitor materials due to its arsenal of advantages, such as high capacitance, low cost, natural abundance, and environmental benignity. However, its low conductivity has hindered its adoption into real-life applications. Compositing MnO2 with conductive additives has proved to be a promising route for the improvement of its power-energy characteristics. Four novel colloidal techniques were developed for the synthesis of MnO2-CNT composites with enhanced performance at high active mass loading. One strategy utilized a Schiff-based linkage of dispersants such as 3,4-Dihydroxybenzaldehyde (DHB) and Toluidine Blue O (TDB) to effectively mix and disperse MnO2 and CNT. Secondly, a co-dispersion technique was also investigated using Gallocyanine to improve dispersion and mixing of MnO2 and MWCNT. Third, a novel liquid-liquid extraction technique opened new avenues in agglomerate-free processing of individual components, which allowed enhanced electrode performance. Lastly, a morphology-modification strategy was also undertaken by synthesizing MnO2 nanorods with the use of advanced organic dispersants to control the aspect ratio and composite nanorods with MWCNT. The second major material investigated was polypyrrole (PPy), a polymer material with high conductivity, ease of synthesis, low-cost, and non-toxicity. However, its low cyclic stability was prevented it from being applied for real-world applications. Certain anionic and aromatic dopants have shown to improve the conductivity and cyclic stability. Therefore, one of the investigations in this work attempted to improve the performance of PPy-CNT composites by use of a novel anionic dopant, Sunset Yellow (SY). For all investigations electrodes with high mass loadings were produced to achieve high areal capacitance, thus ensuring the practicality of the techniques / Thesis / Master of Applied Science (MASc) / Supercapacitors (SCs) and batteries are both electrochemical energy storage devices. While batteries excel at storing energy in high volumes, supercapacitors excel in charging (and discharging) at extremely high rates. It is desirable to obtain the best of both worlds in a single device; high energy volume and fast charging speeds. Although such a feat is not out of the realm of theoretical possibility, current projections forecast supercapacitors to compliment battery technologies instead of replacing them. Nonetheless, constant progression in the field of SCs is needed to sustain and proliferate their adoption into emerging markets. Therefore, the aim of this research was to assist in the endeavours to improve current SC technologies from a materials science standpoint.

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