Development and Testing of a New Optimum Design Code for Hypersonic Wind Tunnel Nozzles, Including Boundary Layer, Turbulence, and Real Gas Effects

A robust and efficient optimization code is developed and validated. The code is used to redesign an existing Mach 12 wind tunnel nozzle and utilizes response surface methodology (RSM) techniques. Explicit, globally second-order, flux-difference-splitting algorithms are used to solve the Navier-Stokes (NS) and Parabolized Navier-Stokes (PNS) flow solvers incorporated into the optimizer code. Either the Baldwin-Lomax or the Yang-Shih k-s turbulence model may be employed in the optimization code. First, 2-D/axisymmetric NS and PNS flow solvers are developed/modified and account for perfect gas/nonequilibrium chemically reacting flows. All solvers are validated against Computational Fluid Dynamics (CFD) and experimental data. The optimization code is subsequently developed and validated. The optimization code is then used to optimize the Mach 12 nozzle design and the computed results are compared with those of the original nozzle. The code is tested for robustness and on three separate occasions locates the global minimum synonymous with the `global best\u27 optimized nozzle. Though an optimized nozzle is obtained, it is not as free of disturbances in the uniform inviscid core at the exit as possibly desired

Report of the Belen, New Mexico School Survey

The purpose of this thesis is to compare the Belen Schools in general with other schools of the State and with accepted educational principles and standards

Detection of HC11N in the Cold Dust Cloud TMC-1

Two consecutive rotational transitions of the long cyanopolyyne HC11N, J=39-38, and J=38-37, have been detected in the cold dust cloud TMC-1 at the frequencies expected from recent laboratory measurements by Travers et al. (1996), and at about the expected intensities. The astronomical lines have a mean radial velocity of 5.8(1) km/s, in good agreement with the shorter cyanopolyynes HC7N and HC9N observed in this very sharp-lined source [5.82(5) and 5.83(5) km/s, respectively]. The column density of HC11N is calculated to be 2.8x10^(11) cm^(-2). The abundance of the cyanopolyynes decreases smoothly with length to HC11N, the decrement from one to the next being about 6 for the longer carbon chains.Comment: plain tex 10 pages plus 3 ps fig file

Oral Health Promotion: Knowledge, Confidence, and Practices in Preventing Early-Severe Childhood Caries of Virginia WIC Program Personnel

Purpose: This study assessed the oral health knowledge, confidence and practices of Virginia personnel in the Special Supplemental Food Program for Women, Infants and Children (WIC). Methods: In 2009, 257 WIC personnel were electronically emailed via an investigator-designed 22-item Survey Monkey® questionnaire. Descriptive statistics, Chi-square and Fishers Exact tests compared personnel demographics and oral health knowledge, confidence and practices at the p≤0.01 and 0.05 significance level. Results: Response rate was 68%. WIC personnel were knowledgeable about basic oral health concepts. More than half of those reporting were not confident assessing for visual signs of dental decay and do not routinely assess for visual signs of decay. Only 4% of personnel apply fluoride therapy. Conclusion: Findings support the need for health promotion/disease prevention at WIC. This study supports the NDHRA priority area, Health Promotion/Disease Prevention: Validate and test assessment instruments/strategies/mechanisms that increase health promotion and disease prevention among diverse populations

Assessing the relevance of digital elevation models to evaluate glacier mass balance : application to Austre Lovénbreen (Spitsbergen, 79 ° N)

International audienceThe volume variation of a glacier is the actual indicator of long term and short term evolution of the glacier behaviour. In order to assess the volume evolution of the Austre Lovénbreen (79 • N) over the last 47 years, we used multiple historical datasets, complemented with our high density GPS tracks acquired in 2007 and 2010. The improved altitude resolution of recent measurement techniques, including phase corrected GPS and LiDAR, reduces the time interval between datasets used for volume subtraction in order to compute the mass balance. We estimate the sub-metre elevation accuracy of most recent measurement techniques to be sufficient to record ice thickness evolutions occurring over a 3 year duration at polar latitudes. The systematic discrepancy between ablation stake measurements and DEM analysis, widely reported in the literature as well as in the current study, yields new questions concerning the similarity and relationship between these two measurement methods. The use of Digital Elevation Model (DEM) has been an attractive alternative measurement technique to estimate glacier area and volume evolution over time with respect to the classical in situ measurement techniques based on ablation stakes. With the availability of historical datasets, whether from ground based maps, aerial photography or satellite data acquisition, such a glacier volume estimate strategy allows for the extension of the analysis duration beyond the current research programmes. Furthermore, these methods do provide a continuous spatial coverage defined by its cell size whereas interpolations based on a limited number of stakes display large spatial uncertainties. In this document, we focus on estimating the altitude accuracy of various datasets acquired between 1962 and 2010, using various techniques ranging from topographic maps to dual frequency skidoo-tracked GPS receivers and the classical aerial and satellite photogrammetric techniques

Effects of Occupational Ultrasonic Noise Exposure on Hearing of Dental Hygienists: A Pilot Study

Purpose. The purpose of this case-control study was to determine whether long-term ultrasonic noise exposure via the dental office environment is related to dental hygienists\u27 hearing status. Methods. Registered dental hygienists (N - 698) who live in the Hampon Roads areas of Virginia were mailed a Dental Hygiene Word History Questionnaire to determine who would meet the inclusion criteria and would be willing to participate in the study. Consenting subjects were categorized into one of two groups, according to ultrasonic sealer usage rate, and matched on age. Persons with known hearing loss due to infection, disease, or congenital defect were excluded from the study. The final sample consisted of 20 dental hygienists with a high ultrasonic usage rate and a matched group of 20 dental hygienists who had a low ultrasonic usage rate. Once the groups were formed, a certified audiologist tested subjects\u27 hearing in each ear via the pure-tone audiometer. Audiometric data were analyzed using the analysis of variance for repeated measures procedure to determine if degree of ultrasonic sealer noise exposure in the dental office environment was significantly related to hearing status in these dental hygienists. Results. Results revealed that the right and left ears were not statistically different in the hearing threshold levels, regardless of group status. However, there was a significant difference in the high ultrasonic usage group and the low ultrasonic usage group at the 3000 Hz. No differences were found at the frequencies of 500, 1000, 2000, 4000, 6000, and 8000 Hz. Conclusions. Based on these outcomes, the ultrasonic sealer is not considered to have a negative effect on the hearing of dental hygienists at 500,1000, 2000, 4000, 6000, and 8000 Hz, but may be related to hearing loss at 3000 Hz. Ultrasonic noise may in fact be affecting dental hygienists\u27 hearing at 3000 Hz, but loss of hearing observed at the higher frequencies may be attributed to other unidentified factors present in both groups

Metal-semiconductor-metal photodetectors on a GeSn-on-insulator platform for 2 µm applications

In this work, the metal-semiconductor-metal photodetectors were demonstrated on the Ge0.91Sn0.09-on-insulator (GeSnOI) platform. The responsivity was 0.24 and 0.06 A/W at wavelengths of 1,600 and 2,003 nm, respectively. Through a systematic study, it is revealed that the photodetectors can potentially detect wavelength beyond 2,200 nm. The dark current density was measured to be 4.6 A/cm2 for GeSnOI waveguide-shaped photodetectors. The 3 dB bandwidth was observed to be 1.26 and 0.81 GHz at 1,550 and 2,000 nm wavelengths, respectively. This work opens up an opportunity for low-cost 2 µm wavelength photodetection on the GeSn/Ge interface-free GeSnOI platform

Characterizing the Initial Phase of Epidemic Growth on some Empirical Networks

A key parameter in models for the spread of infectious diseases is the basic reproduction number $R_0$, which is the expected number of secondary cases a typical infected primary case infects during its infectious period in a large mostly susceptible population. In order for this quantity to be meaningful, the initial expected growth of the number of infectious individuals in the large-population limit should be exponential. We investigate to what extent this assumption is valid by performing repeated simulations of epidemics on selected empirical networks, viewing each epidemic as a random process in discrete time. The initial phase of each epidemic is analyzed by fitting the number of infected people at each time step to a generalised growth model, allowing for estimating the shape of the growth. For reference, similar investigations are done on some elementary graphs such as integer lattices in different dimensions and configuration model graphs, for which the early epidemic behaviour is known. We find that for the empirical networks tested in this paper, exponential growth characterizes the early stages of the epidemic, except when the network is restricted by a strong low-dimensional spacial constraint, such as is the case for the two-dimensional square lattice. However, on finite integer lattices of sufficiently high dimension, the early development of epidemics shows exponential growth.Comment: To be included in the conference proceedings for SPAS 2017 (International Conference on Stochastic Processes and Algebraic Structures), October 4-6, 201