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Exposure to high sound levels may lead to a variety of hearing abnormalities, including Noise-Induced Hearing Loss (NIHL). Pre-professional university music majors may experience frequent exposure to elevated sound levels, and this may have implications on their future career prospects (Jansen, Helleman, Dreschler & de Laat, 2009). Studies suggest that college students (aged 18-25) who participate in instrumental music activities are particularly vulnerable to hearing damage and NIHL (Phillips, Henrich, & Mace, 2010). The Occupational Safety and Health Administration (OSHA) standards for sound levels were last revised in October 1974, and remain as the maximum allowable noise levels in the workplace as enforced by law in the United States (U.S. Department of Labor, 2009). The standards are based on a permissible sound exposure of 90 dB for a duration of up to eight hours. Currently, the OSHA decibel exchange rate is set at 5 dB, with exchange rate defined as the amount of decibels at which the permissible sound level is reduced by 50%. The National Institute of Occupational Safety and Health (NIOSH), on the other hand, recommends no more than 85 dB for up to eight hours with a 3 dB exchange rate (Center for Disease Control and Prevention, 2011). The purpose of this study was to collect and analyze the sound load exposure of a population of university music students participating in instrumental music ensemble rehearsals. The subject venue is described as Fine Arts Center (FAC) 2007, located within the Cowan Fine Arts Center on the campus of the University of Texas at Tyler. This room serves as a rehearsal venue for a student jazz ensemble, a student jazz combo, and the university Wind Ensemble, all of which were recorded for this study. The Wind Ensemble and jazz combo met three times per week on Monday, Wednesday, and Friday from 12:30 to 1:45 and 3:00 to 4:15, respectively, while the jazz ensemble met twice a week on Tuesday and Thursday from 2:00 to 3:15. All measurements were taken using an ExTech 407764 Datalogging Sound Level Meter. Data was collected every week and saved to an external memory storage device. The datalogger was then cleared and reset to collect subsequent data sets. The results of the study were based on data retrieved from the datalogger over a period of eight weeks, spanning September 19 to November 24, 2012. During this time, a total of 33 recordings were collected, each with an average duration of 1.28 hours (1 hour and 17 minutes). The lowest decibel values recorded fell below the minimum value of the range set for the meter (30dB), whereas the loudest recorded noise levels reached 130 dB, which was the highest value of the range set for the meter. Out of a total of 33 recording sets, none exceeded the mandatory OSHA values for safety regulations, and only one exceeded the recommended NIOSH values. This information suggests that the room in which the recordings took place is safe for the amount of sound being produced according to the legal OSHA workplace values; however, due to the proximity of some recording sets to the maximum allowable dosage level, it would be common in most manufacturing industries to implement a hearing conservation program. [Paper presented at the Annual Meeting of the Texas Music Educators Association (San Antonio, TX, Feb 2014).]

Direct evaporative cooling (DEC) is a technology that is continuously expanding into different areas of study. The foundation of this process has been built through expansive research efforts and physical experimental data. The ability to accurately model and predict the performance of DEC systems allows the energy-efficient process to gain traction in HVAC applications, however, the inconsistencies present among research efforts created discontinuities in the reproduction of a system. By reviewing current literature, the discrepancies in the defining methodologies of how DEC systems are defined and predicted can provide insight to future research. This review depicts the different approaches taken in recent research to define the equations that govern the thermodynamic processes, the different materials used in the process, and the models used to predict the performance of DEC systems. By identifying the most common practices in current research, the gaps in literature can be recognized and overcome in further efforts. [ABSTRACT FROM AUTHOR]

Indoor Air Quality (IAQ) contributes to the health and comfort of people living and working indoors. Poor IAQ can be linked to indoor and outdoor sources of contaminants. One recent solution for improving IAQ is the use of Electrostatic (ES) air cleaning technology. An ES air cleaner can be installed in a heating, ventilation, and air conditioning system where it pre-filters large dust particles and shocks smaller particles into a collection tray. However, ES air cleaners have been known to give off ozone as a by-product, which is, itself, an air contaminant. Ozone is found outdoors as product of sunlight combining nitrogen oxides and volatile organic compounds generated from man-made pollution. Indoor ozone concentration will depend on the introduction of outdoor ozone indoors through natural ventilation, mechanical ventilation, and infiltration through the building's envelope (in order of importance). Two different ES air cleaners, A and B, were installed in the air conditioning system of research house #2 of the TRANE Residential Heating and Cooling Research Lab at the University of Texas at Tyler. A series of ozone experiments were conducted, which included measuring the baseline ozone levels at the research houses with different levels of insulation, observing the increase in ozone due to the powering on of mechanical ventilation, and observing the increase in ozone due to the powering on of the installed ES air cleaners. The baseline ozone levels observed in research house #2, whose envelope is more tightly insulated, was found to be lower than in research house #1 whose envelope is less tightly insulated. With regards to mechanical ventilation, an increase in ozone levels were seen in addition to an even higher increase in ozone levels when the ES air cleaners were powered on in tandem. In terms of the single contribution of the ES air cleaners in raising indoor ozone levels, the data shows that although the ES air cleaners increased the ozone concentration in the house, the levels are not of concern as they were less than the FDA limit on indoor ozone generation. [ABSTRACT FROM AUTHOR]