Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains x, 83 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 79-83).

Thesis (M.S. in Operations Research)--Naval Postgraduate School, December 2002. / Thesis advisor(s): Steven E. Pilnick, Thomas H. Hoivik. Includes bibliographical references (p. 65-66). Also available online.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 140-150). Also available in electronic version.

Variation in exposure to environmental microbial communities has been implicated in the etiology of allergies, asthma and other chronic and immune disorders. In particular, preliminary research suggests that exposure to a high diversity of microbes during early life, for example through living in highly vegetated environments like farms or forests, may have specific health benefits, including immune system development and stimulation. In the face of rapidly growing cities and potential reductions in urban greenspace, it is vital to clarify our understanding of the relationship between vegetation and microbial communities so that we can better design cities that support human health. To explore whether and how urban airborne bacterial communities vary with the amount and structural diversity of nearby vegetation, I used passive air sampling and culture-independent microbial DNA sequencing combined with more traditional landscape architecture tools, including geographic information systems (GIS) and remote sensing data. The results indicated that locations with little vegetation (i.e., paved parking lots) were marked by significantly different bacterial composition from areas that were heavily vegetated (parks and forests). These differences were largely driven by taxonomic groups and indicator species that were enriched at certain sites. My work also shows that regional agricultural activities during the summer may have a substantial effect on airborne bacterial communities in the Eugene-Springfield metropolitan area (Oregon), specifically through elevated abundance of Sphingomonas faeni, a taxon previously isolated from hay dust. The second part of my work focused on building a conceptual bridge between scientific findings and potential design principles that can be tested in practical application. I performed a narrative review of vegetation-health, vegetation-microbe, and microbe-health relationships, which formed the foundation of a framework to translate scientific findings into design-relevant concepts. Strengthening this linkage between science and design will help ensure that research questions are relevant to design practice and that new scientific knowledge is accessible to designers. This dissertation includes previously published and unpublished co-authored material. / 2020-09-06

QC 20110620

Mobility models serve as the foundation for evaluating and designing airborne networks. Due to the significant impact of mobility models on the network performance, mobility models for airborne networks (ANs) must realistically capture the attributes of ANs. In this paper, I develop a comprehensive modeling framework for ANs. The work I have done is concluded as the following three parts. First, I perform a comprehensive and comparative analysis of AN mobility models and evaluate the models based on several metrics: 1) networking performance, 2) ability to capture the mobility attributes of ANs, 3) randomness levels and 4) associated applications. Second, I develop two 3D mobility models and realistic boundary models. The mobility models follow physical laws behind aircraft maneuvering and therefore capture the characteristics of aircraft trajectories. Third, I suggest an estimation procedure to extract parameters in one of the models that I developed from real flight test data. The good match between the estimated trajectories and real flight trajectories also validate the suitability of the model. The mobility models and the estimation procedure lead to the creation of “realistic” simulation and evaluation environment for airborne networks.

There are a number of inherent problems associated with the analysis of polycyclic aromatic compounds (PAC) in airborne particulate matter. The compounds of interest constitute a very small fraction of the total sample, but consist of hundreds of different components. Therefore, analytical techniques with very high resolving power are required. To try to address these problems, methods have been developed and improved to isolate, and subsequently profile, and identify the PAC present in typical airborne particulate samples. Since no single chromatographic technique can provide the desired resolution, a multi-stage clean-up scheme was required prior to analysis. Two methods were investigated in this study. Both methods used a Soxhlet extraction followed by fractionation using an adsorption chromatography step (silica or alumina) and Sephadex LH-20 to isolate the PAC fraction from the other organic constituents. Another problem associated with the analysis of PAC in airborne particulate matter was because of the method of sample collection. It was believed that there were changes in the chemical composition of the particulate and hence the PAC, during sample collection using a Hi-Vol sampler. Artifacts were being formed by reaction of gaseous pollutants with the particulate collected on the filter. An experiment was established to show that the addition of a denuder bundle to a Hi-Vol sampler could reduce this artifact formation during sampling by removing the reactive gases prior to the surface of the filter. The value of the denuder bundle was evaluated by comparison of the PAC from the denuder Hi-Vol with a standard Hi-Vol. Normal-phase HPLC coupled with mass spectrometry was shown to be a good method to compare the PAC in these samples. Some differences between standard and denuder Hi-Vol samples were observed in laboratory experiments, while the results from field sampling were inconclusive. The use of a parallel column gas chromatography-mass spectrometry (GC-MS) (also called third order chromatography) technique was investigated to determine its viability for the identification of the diverse range of PAC present in environmental samples. The PAC . in the NBS urban dust sample (SRM 1649) was analyzed to evaluate the method. To aid in data processing, a semi-automated peak detection routine has been developed. This routine used programs to aid in the data processing by simplifying peak detection and allow calculation of the retention indices of the components. Using the information supplied by the retention indices and the mass spectra, a data base was developed that was applied to a typical airborne particulate sample. / Thesis / Doctor of Philosophy (PhD)

No description available.

No / Recent progress in the development of European standards has allowed the in situ testing of roadside noise barriers. CEN/TS 1793-5 describes a test method using maximum length sequences (MLS) for the characterisation of airborne sound insulation. However, many barriers are tested according to a laboratory standard, EN 1793-2, based on measurements carried out in reverberant chambers and in the case of timber barriers with a relatively low airborne sound insulation it is not clear to what extent the results of the two tests compare. The paper describes the results of tests carried out using both methods. Six samples of timber barrier were compared including single-leaf and double-leaf constructions and single-leaf constructions with an absorptive core. Very good agreement was found especially when account was taken of the valid frequency range in each test method. The results open up the possibility of routinely evaluating the performance of timber barriers at the roadside where build quality can be variable and there are concerns that the acoustic performance may not match that obtained under laboratory test conditions where typically the barrier is more carefully constructed.

Yes / The in situ measurement of the airborne sound insulation, as outlined in EN 1793-6:2012, is becoming a common means of quantifying the performance of road traffic noise reducing devices. Newly installed products can be tested to reveal any construction defects and periodic testing can help to identify long term weaknesses in a design. The method permits measurements to be conducted in the presence of background noise from traffic, through the use of impulse response measurement techniques, and is sensitive to sound leakage. Factors influencing the measured airborne sound insulation are discussed, with reference to measurements conducted on a range of traffic noise barriers located around Auckland, New Zealand. These include the influence of sound leakage in the form of hidden defects and visible air gaps, signal-to-noise ratio, and noise barrier height. The measurement results are found to be influenced by the presence of hidden defects and small air gaps, with larger air gaps making the choice of measurement position critical. A signal-to-noise ratio calculation method is proposed, and is used to show how the calculated airborne sound insulation varies with signal-to-noise ratio. It is shown that the measurement results are influenced by barrier height, through the need for reduced length Adrienne temporal windows to remove the diffraction components, prohibiting the direct comparison of results from noise barriers with differing heights. / The authors would like to thank the NZ Transport Agency for sponsoring the Auckland traffic noise barrier testing work, and the Auckland Motorway Alliance for assisting with access to the test sites.