Investigation and literature review of unilateral hearing loss

Literature and research were gathered and analyzed to determine the impact UHL has on a child’s education, speech and language development. The effects of early intervention and amplification were also analyzed

Analysis of particulate size distribution and concentrations from simulated jet engine bleed air incidents

Engine oil migrating into the bleed air stream of aircraft environmental control systems occurs with enough frequency and deleterious effects to generate significant public interest. While previous work has explored the chemical makeup of the contaminants in the aircraft cabin during these events, little is known about the characteristics of the aerosol resulting from oil contamination of bleed air. This paper presents particle counter data (giving both size distributions and concentration information) of the oil droplets from simulated jet engine bleed air. Four particle counters—a scanning mobility analyzer, an aerodynamic particle-sizer, an optical particle counter, and a water-based condensation particle counter—were used in the study encompassing a size range from 13nm to 20μm. The aerosol characterization is given for different bleed air temperatures and pressures. The data show a substantial increase of ultra-fine particles as the temperature is increased to the maximum temperatures expected during normal aircraft operation. This increase in ultra-fine particles is consistent with smoke generated from the oil. The pressure of the bleed air had little discernible effect on the particle-size and concentration

Aircraft recirculation filter for air quality and incident assessment

The current research examines the possibility of using recirculation filters from aircraft to document the nature of air quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator (BAS) was developed to simulate an engine oil leak and samples were analyzed with gas chromatograph-mass spectrometry (GCMS). These samples provided a concrete link between tricresyl phosphates (TCPs) and a homologous series of synthetic pentaerythritol esters from oil and contaminants found on the sample paper. The second step was to test 184 used aircraft filters with the same GC-MS system: of that total, 107 were standard filters and 77 nonstandard. Four of the standard filters had both markers for oil, with the homologous series synthetic pentaerythritol esters being the less common marker. It was also found that 90% of the filters had some detectable level of TCPs. Of the 77 nonstandard filters, 30 had both markers for oil, a significantly higher percent than the standard filters

High-density sub-100-nm peptide-gold nanoparticle complexes improve vaccine presentation by dendritic cells in vitro

Nanocarriers have been explored to improve the delivery of tumor antigens to dendritic cells (DCs). Gold nanoparticles are attractive nanocarriers because they are inert, non-toxic, and can be readily endocytosed by DCs. Here, we designed novel gold-based nanovaccines (AuNVs) using a simple self-assembling bottom-up conjugation method to generate high-peptide density delivery and effective immune responses with limited toxicity. AuNVs were synthesized using a self-assembling conjugation method and optimized using DC-to-splenocyte interferon-γ enzyme-linked immunosorbent spot assays. The AuNV design has shown successful peptide conjugation with approximately 90% yield while remaining smaller than 80 nm in diameter. DCs uptake AuNVs with minimal toxicity and are able to process the vaccine peptides on the particles to stimulate cytotoxic T lymphocytes (CTLs). These high-peptide density AuNVs can stimulate CTLs better than free peptides and have great potential as carriers for various vaccine types

Challenges and Opportunities: Student and Practitioner Experiences During COVID-19

This report elevates the voices of those closest to the work—students, AmeriCorps members and teachers – to bring to life their extraordinary efforts to support student success. It draws insights from City Year's work across the country and highlights how three City Year sites and Compass Academy (a charter public middle school in Denver cofounded by City Year, Johns Hopkins University School of Education, and the Denver community in 2015) have adjusted their practices to respond to the unique challenges that students are facing in the wake of COVID-19- induced school closures.The primary sources of data for this research project were eight focus groups, two interviews, and one student survey. Secondary data sources for this project include Compass Academy artifacts, 2020-2021 Compass Academy Mid-Year Survey results as well as the 2020-2021 City Year AmeriCorps member, teacher and principal survey results

Electrical switching in bulk samples of 0.15As-0.12Ge-0.73Te glass

Switching in bulk samples of 0.15As--0.12Ge--0.73Te glass is found to be caused predominantly by the thermal switching mechanism for near threshold applied voltages. Switching also occurred by the thermal mechanism even for applied voltages an order of magnitude above the threshold voltage of the sample. In order to investigate a switching event in this glass sample, a constant voltage pulse was applied to the sample and the delay time and the electrical energy input to the sample during the delay time measured. A log--log plot of the energy input to the sample during a delay time of 1.00 s as a function of the electrode spacing on the sample's surface was found to have a slope of approximately 1.6. For the theoretical study of the thermal switching mechanism, a one-dimensional calculation of the heat balance equation with radial heat flow was made and the results of the calculation followed the same trends as the experimental data. The large scatter in parts of the data and the increase in the average resistance of the sample for a switching event with near threshold applied voltages could not be explained by the thermal switching mechanism. These effects could be a manifestation of the structural changes which probably occur in the sample as a result of the high temperatures present at the moment of switching. 33 fig

In-tube evaporation and condensation of HFC-134a and CFC-12 with various lubricant mixtures

Mandates currently in place by the Environmental Protection Agency require use of new environmentally acceptable refrigerants by 1996. Implementation of these new refrigerants by refrigeration and air-conditioning manufactures requires design data for the various components of these systems. This study focused on obtaining design data for evaporators and condensers of vapor compression systems. Specifically, a new environmentally acceptable refrigerant HFC-134a, which is targeted as a replacement for refrigerant CFC-12, was tested in an instrumented evaporator and condenser and their performance measured;Heat transfer coefficients and pressure drops were measured during evaporation and condensation of HFC-134a and CFC-12 in smooth and micro-fin tubes. Two different diameter smooth tubes and micro-fin tubes were tested: 9.52-mm outside diameter tubes and 12.7-mm outside diameter tubes. Micro-fin tubes are characterized by the numerous small fins that spiral down the inner surface of the tube. The micro-fin tubes used in this study had 60 fins with a spiral angle of 17° and fin heights of 0.2 mm. The heat transfer coefficients and pressure drops measured in this study were averages over the 3.66-m long test tubes. The refrigerant mass flux was varied from 125 kg/m[superscript]2·s to 375 kg/m[superscript]2·s in both the smooth and micro-fin tubes;The experimental data showed a significant increase in the performance of HFC-134a in the micro-fin tube as compared to the smooth tube. Specifically, evaporation heat transfer coefficients were increased by 50% to 100% with only a 10% to 30% increase in evaporation pressure drop, while condensation heat transfer coefficients were increased by 100% to 200% with a 40% to 100% increase in condensation pressure drop. Similar results were obtained for pure CFC-12 in the micro-fin tube;The effects of lubricant concentration (\prec5%) on the performance of HFC-134a and CFC-12 were also studied. HFC-134a was tested with a penta erythritol ester mixed-acid lubricant and a penta erythritol ester branched-acid lubricant. CFC-12 was tested with a naphthenic lubricant. Lubricant concentration in general decreased the heat transfer performance of refrigerants. The only exception was evaporation at low lubricant concentrations were the heat transfer coefficients were slightly enhanced by refrigerant/lubricant mixtures. Pressure drop during evaporation and condensation was increased by the addition of lubricant in most cases

Parent views and perceptions of the Bayfield SAGE program

Includes bibliographical references

3-D Seismic Exploration Project, Ute Indian Tribe, Uintah & Ouray Reservation, Uintah County, Utah

The objectives of this North Hill Creek 3-D seismic survey were to: (1) cover as large an area as possible with available budget; (2) obtain high quality data throughout the depth range of the prospective geologic formations of 2,000' to 12,000' to image both gross structures and more subtle structural and stratigraphic elements; (3) overcome the challenges posed by a hard, reflective sandstone that cropped out or was buried just a few feet below the surface under most of the survey area; and (4) run a safe survey