Mitigation of High Alkalinity in Leachates of Aged Steel Slag

Steel slag, an abundant by-product of the steel-making industry, after it is aged, has a huge potential for use as an aggregate in road construction. However, the high pH of steel slag seepage (pH≥12) is a major impediment in its beneficial use. Analyses on aged steel slag samples demonstrated that the alkalinity producing capacity of aged steel slag samples strongly correlated to Ca(OH)2 dissolution and that prolonged aging periods have marginal effects on overall alkalinity. Treatment methods that included bitumen-coating, bathing in Al(III) solutions and addition of an alum-based drinking water treatment residual (WTR) were evaluated based on reduction in pH levels and leachate alkalinity. 10% (wt./wt.) alum-based drinking water treatment residual (WTR) addition to slag was determined to be the most successful mitigation method, providing 65−70% reduction in alkalinity both in batch-type and column leach tests, but final leachate pH was only 0.5−1 units lower and leachates were contaminated by dissolved Al(+III) (≥3−4 mM). Based on the interpretation of calculated saturation indices and SEM and EDX analyses, formation of calcium sulfoaluminate phases (i.e., ettringite and monosulfate) was suggested as the mechanism behind alkalinity mitigation upon WTR-modification. The residual alkalinity in WTR-amended slag leachates was able to be completely eliminated utilizing a biosolids compost with high base neutralization capacity. In column leach tests, effluent pH levels below 7 were maintained for 58−74 pore volumes worth of WTR-amended slag leachate using 0.13 kg compost (dry wt.) per 1 kg WTR-amended slag on average; also, dissolved Al(+III) was strongly retained on the compost.

THE EFFECT OF A PROGRAM OF PORTABLE ELECTRONIC PIANO KEYBOARD EXPERIENCE ON THE ACQUISITION OF SIGHT-SINGING SKILL IN THE NOVICE HIGH SCHOOL CHORUS

The problem was to determine whether a method of aural and visual vocal training that included a program of portable electronic piano keyboard experience would be more effective in teaching sight-singing skills to novice high school chorus students than a method that included only aural and visual vocal training. A sub-problem was to determine whether novice chorus students enjoyed playing electronic keyboards in chorus as a reinforcement experience in sight-singing training. Students were randomly assigned to two treatment groups, tested with the Musical Aptitude Profile, Tonal Imagery, part A, and then trained separately. The experimental group sang repetitions of melodic patterns and utilized techniques associated with the Kodály Method while simultaneously playing keyboard. The comparison group received a similar treatment without using keyboards. The students were pre- and post-tested in sight-singing using the Vocal Sight-Reading Inventory. Results of the Analysis of Covariance using MAP scores as the covariate revealed no significant difference (p<.05) between post-test scores of the two groups. Improvement was noted in 96% of students from pre-test to post-test regardless of grouping. The repeated measures ANOVA revealed a significant relationship (p<.006) between aptitude group and post-test score. High aptitude students in both groups were found to benefit more from the training than low aptitude students. High aptitude keyboard group students achieved an average gain score that was 8.67 points higher than the comparison group. Of the total experimental group, 92% enjoyed playing keyboards in chorus. It is recommended that future research be undertaken to study the use of keyboards with advanced high school choruses and with uncertain singers in the high school chorus. Research is also needed to develop graded, valid, and reliable sight-singing tests for use in high school chorus. Techniques of the Kodály Method should be further investigated for use in high school sight-singing training.

Reclaiming the Vocal High Ground: Performing Baroque Repertoire in a Modern World

The early music revival of the late twentieth century revolutionized music with the birth of historically lnformed performance. With this revolution came a stereotype of the "early music singing voice" as small, bright, straight-toned, and unfortunately, often inferior techrucally to the mainstream opera singer. An assessment of the validity of this stereotype was made though readings of treatises and modern manuals of performance practice, and through listening to recordings. Sources on ornamentation, recitative, dance rhythm, and baroque gesture were examined, resulting in the finding that these issues are far more important to historical accuracy than are voice timbre and size. This dissertation is comprised of three historically informed performances intended to satisfy both the early music specialist and the mainstream voice teacher. Program One (May 15, 2004) is a performance of The "Peasant" Cantata, BWV 212, by J.S. Bach, with The Bach Sinfonia at the Washington Conservatory of Music. Program Two (January 29, 2005) is the role of Eurilla in a staged production of Antonio Vivaldi's serenata, Eurilla e Alcindo. The performance is a collaboration with the Baltimore-based ensemble, La Rocinante, and is conducted from the keyboard by Joseph Gascho. Program Three (March 14, 2005) is a solo recital entitled, Fairest Isle: Music of Baroque London. All three programs are documented in a digital audio format available on compact disc, with accompanying programs and notes also available in digital format.

High School Choral Students' Perceptions of Choral Music Experience

The purpose of this study is to explore high school students' perceptions of their choral experiences, providing an understanding of students' ongoing perspectives of choral experience. Specifically, how have these experiences influenced the formation of their musical identities as members of a choral ensemble? The researcher collected data from the three participants during a full school year. The participants were current students in the researcher's advanced choral ensemble. Through axial coding, three themes emerged: musical interpretation, attitude, and group efficacy. The study revealed that experienced choral students have well-informed musical perspectives that influence their choral experiences. Implications for music education include using students' perspectives for creating rehearsal strategies, planning and programming performances, and fostering a nurturing learning atmosphere. Suggestions for further research include comparing experienced students to non-experienced students, comparing ensembles with student-chosen repertoire to those with director-chosen repertoire, and further examining the impact of choral experience on musical identity.

Assessing the viability of studying motion indicators of autism spectrum disorders in infants at high and low risk for ASD using a passive motion capture system

Gemstone Team AMIRA

TEACHING HIGH SCHOOL STUDENTS THE BEST CHORAL REPERTOIRE FROM THE GREAT COMPOSERS: MASTERWORKS AVAILABLE FOR IMMEDIATE, FREE ACCESS FROM THE CHORAL PUBLIC DOMAIN LIBRARY

Studying the choral works of the great composers of the past is always a worthy endeavor. For those aspiring to create an excellent high school choral program, it is critical to a student's musical foundation and heritage. Choral educators who teach high school are often bombarded with the most recently published new choral works, when they have a trove of excellent pieces right at their fingertips through websites like the Choral Public Domain Library (CPDL), all available at no cost. This project will explore the pedagogical reasons why this canon of public domain choral music should be taught at the high school level. A thorough guide to CPDL and an anthology of 200 works available on CPDL will provide the conductor with resources for programming this music. Though choral music in the public domain is free to all, publishers still publish this music and adhere copyright claims. This can create mistrust of legitimate editions on CPDL; why are they available at no cost when publishers are claiming copyright on similar editions? These issues will be thoroughly discussed in this project. For any given work on CPDL, there may be multiple editions available on the site. Choosing the right edition requires knowledge about basic editorial principles, especially for works written during the Renaissance period. A detailed discussion of these principles will provide the conductor with the tools needed to choose the best edition for his or her ensemble.

Improving Photovoltaics with High Luminescence Efficiency Quantum Dot Layers

A solar cell relies on its ability to turn photons into current. Because short wavelength photons are typically absorbed near the top surface of a cell, the generated charge carriers recombine before being collected. But when a layer of quantum dots (nanoscale semiconductor particles) is placed on top of the cell, it absorbs short wavelength photons and emits them into the cell at longer wavelengths, which enables more efficient carrier collection. However, the resulting power conversion efficiency of the system depends critically on the quantum dot luminescence efficiency – the nature of this relationship was previously unknown. Our calculations suggest that a quantum dot layer must have high luminescence efficiency (at least 80%) to improve the current output of existing photovoltaic (PV) cells; otherwise, it may worsen the cell’s efficiency. Our quantum dot layer (using quantum dots with over 85% quantum yield) slightly reduced the efficiency of our PV cells. We observed a decrease in short circuit current of a commercial-grade cell from 0.1977 A to 0.1826 A, a 7.6% drop, suggesting that improved optical coupling from the quantum dot emission into the solar cell is needed. With better optical coupling, we predict current enhancements between ~6% and ~8% for a solar cell that already has an antireflection coating. Such improvements could have important commercial impacts if the coating could be deployed in a scalable fashion.