Retrievals of atmospheric information from satellite observations permit the investigation of otherwise inaccessible atmospheric phenomena. The recovery of this information from optical instrumentation located in orbit requires both an inversion algorithm like the Saskatchewan Multiplicative Algebraic Reconstruction Technique and a forward model like the SASKTRAN radiative transfer model. These are used together at the University of Saskatchewan to retrieve sulphate aerosol extinction profiles from the radiance measurements made by the Canadian built OSIRIS instrument. Although these retrievals are highly successful the process currently does not consider the polarization of light or OSIRIS's polarization sensitivities because SASKTRAN is a scalar model. In this work the development of a vector version of SASKTRAN that can perform polarized radiative transfer calculations is presented.<p> The vector SASKTRAN's results compare favorably with vector SCIATRAN, another polarized model that is in development at the University of Bremen. Comparisons of the stratospheric aerosol retrieval vectors generated from the scalar and vector SASKTRAN results indicate that the polarized calculations are an important factor in future work to improve the aerosol retrievals and to recover particle size or composition information.

A concentric pneumatic nebulizer (CPN) and a custom designed flow focusing nebulizer (FFN) are characterized. As will be shown, the classical Nukiyama-Tanasawa and Rizk-Lefebvre models lead to erroneous size prediction for the concentric nebulizer under typical operating conditions due to its specific design, geometry, dimension and different flow regimes. The models are then modified to improve the agreement with the experimental results. The size prediction of the modified models together with the spray velocity characterization are used to determine the overall nebulizer efficiency and also employed as input to a new Maximum Entropy Principle (MEP) based model to predict joint size-velocity distribution analytically. The new MEP model is exploited to study the local variation of size-velocity distribution in contrast to the classical models where MEP is applied globally to the entire spray cross section. As will be demonstrated, the velocity distribution of the classical MEP models shows poor agreement with experiments for the cases under study. Modifications to the original MEP modeling are proposed to overcome this deficiency. In addition, the new joint size-velocity distribution agrees better with our general understanding of the drag law and yields realistic results. / PhD

Background: The delivery of an aerosol via a tracheostomy tube has been previously described with both a tracheostomy collar and a T-piece, but not with a Wright mask, or aerosol mask. The primary purpose of this study was to quantify lung doses using different interfaces: tracheostomy collar, Wright mask, and aerosol mask. The secondary purposes were to compare albuterol delivery between an opened vs. a closed fenestration hole and also to determine the effect of inspiratory time:expiratory time (I:E) ratio on aerosol delivery. Methods: A teaching mannequin (Medical Plastic Labs, Gatesville, TX) with a tracheostomy opening was used. Two of the mannequin's bronchi were connected to a "Y" adaptor, which was attached to a collecting filter (Respirgard ™ II 303, Vital Signs, Englewood, CO), which was connected to a breathing simulator (Harvard Apparatus Dual Phase Control Respirator Pump, Holliston, MA) through a corrugated tube. Settings for spontaneous breathing were respiratory rate 20/min, and tidal volume 400 mL. The I:E ratios were adjusted in the first and second comparisons at 2:1 and 1:2, respectively. The nebulizer was operated by a flow meter (Timemeter, St. Louis, MO) at 8 L/min with 100% oxygen. In every condition, the flow was discontinued at the end of nebulization. The nebulizer was attached to the tracheostomy collar (AirLife™, Cardinal Health, McGaw Park, IL) in the first group, the Wright mask (Wright Solutions LLC, Marathon, FL) in the second group, and the aerosol mask (AirLife™, Cardinal Health, McGaw, IL) in the third group. Drug was eluted from the filter and analyzed by spectrophotometry (276 nm). Data Analysis: Paired t-test, one-way analysis of variance (ANOVA), repeated measures ANOVA, post-hoc and pairwise comparisons were performed at the significance level of .05, using PASW version 18.0. Results: Aerosol delivery was greater with the tracheostomy collar than the Wright mask and aerosol mask (p < .05). Closing the fenestration hole increased aerosol deposition significantly at 2:1 ratio (p = .04) compared to opening the fenestration at 1:2 ratio. I:E ratio and aerosol delivery were directly related. Increasing I:E ratio from 1:2 to 2:1 improved aerosol delivery significantly with tracheostomy collar-fenestration opened (p = .009), Wright mask (p = .02) and aerosol mask (p = .01). Conclusion: This study indicates that the use of a tracheostomy collar is the best method of delivering aerosol therapy among the three interfaces. The I:E ratio of 2:1 caused greater aerosol deposition than 1:2 ratio. The aerosol deposition was better when the fenestration hole was closed compared with opened fenestration.

Introduction: Although patients with an acute increase in airflow resistance may require aerosol therapy and noninvasive positive pressure ventilation (NIPPV), the efficiency of different aerosol devices and masks during NIPPV is not well understood. The purpose of this study was to determine the efficiency of a jet nebulizer (JN), a vibrating mesh nebulizer (VMN) and a pressurized metered-dose inhaler (pMDI) and three different masks during NIPPV. Method: An in vitro lung model consisted of the upper airway of an adult teaching manikin with a collecting filter at the level of the bronchi attached to a passive test lung. NIPPV was administered via full face mask for the first experiment (AF531 oro-nasal) with an IPAP/EPAP of 20/5 cm H2O and a respiratory rate of 15 Breath per minute (BPM). Aerosol generators were placed between the leak in the circuit and the mask. Albuterol sulfate (2.5 mg/ 3 ml) was nebulized with the JN (Micromist) and the VMN (Aeroneb Solo). Four puffs (108 µg/puff) were administered with the pMDI (ProAir HFA) with a spacer (Aerovent) that first was placed in the recommended normal position (pMDI-N) with aerosol plume directed towards patient, and then in the reversed position (pMDI-R), with aerosol directed away from patient (n=3). In the second experiment, three masks were used 1) the Performax mask, 2) the AF531 oro-nasal mask, and 3) the Performa track mask. Performa track mask was tested with only Aeroneb solo while other masks were tested with both Aeroneb solo and NIVO VMNs. In both experiments, filters were eluted with 0.1 HCl and analyzed by a spectrophotometer at 276 nm. Residual volumes were determined gravimetrically. Result: Descriptive statistics, one-way analysis of variance (ANOVA), and independent t tests were used. Statistical significance was set at p<0.05. During NIPPV, inhaled mass (IM) and inhaled mass percent (IM %) varied significantly (p=0.042 and p=0.028, respectively). Aerosol delivery with the JN was the lowest during NIPPV. The VMN has a significantly lower residual volume than the JN (p=0.0001). No statistical difference in efficiency was found between the two pMDI orientations (p=0.253). In the second experiment, oro nasal mask with Aeroneb Solo VMN results in the highest IM which was significant when compared with all other masks(p=0.0001). No statistical difference can be found between other masks. Conclusion: The JN was less efficient than the VMN and the pMDI in either orientation. The type of aerosol device used during NIPPV influenced aerosol delivery in this simulated adult lung model. Oro nasal mask with Aeroneb Solo VMN provided the highest IM.

The freezing kinetics of binary nitric acid/water aerosols is of fundamental importance to the modelling of polar stratospheric clouds and the role they in ozone depletion over the Arctic/Antarctic regions. Cirrus clouds are also often composed of nitric acid solutions, hence an understanding of freezing process in these aerosols also aids in modelling the earth's radiation budget and global warming. This thesis explores the kinetic phase diagram of nitric acid/water aerosols with sizes ranging between 0. 2 and 1. 5 mm in radius and concentrations ranging between pure water and 0. 45 mole fraction HNO3. Although the kinetic phase diagram has now been studied between 0. 46 mole fraction HNO3 and pure water, more data is needed in the region between 0. 18 and 0. 25 mole fraction HNO3 to confirm the results reported. The project described in this thesis are a continuation of a project begun by Allan Bertram. The measurements involving aerosols with compositions greater than 0. 25 mole fraction HNO3 were carried out as part of Allan Bertram's Ph. D. thesis (see ref. 20) These data were later examined using a more comprehensive data analysis method (as presented in this thesis) in an effort to obtain a more complete understanding of this system.

Retrievals of atmospheric information from satellite observations permit the investigation of otherwise inaccessible atmospheric phenomena. The recovery of this information from optical instrumentation located in orbit requires both an inversion algorithm like the Saskatchewan Multiplicative Algebraic Reconstruction Technique and a forward model like the SASKTRAN radiative transfer model. These are used together at the University of Saskatchewan to retrieve sulphate aerosol extinction profiles from the radiance measurements made by the Canadian built OSIRIS instrument. Although these retrievals are highly successful the process currently does not consider the polarization of light or OSIRIS's polarization sensitivities because SASKTRAN is a scalar model. In this work the development of a vector version of SASKTRAN that can perform polarized radiative transfer calculations is presented.<p> The vector SASKTRAN's results compare favorably with vector SCIATRAN, another polarized model that is in development at the University of Bremen. Comparisons of the stratospheric aerosol retrieval vectors generated from the scalar and vector SASKTRAN results indicate that the polarized calculations are an important factor in future work to improve the aerosol retrievals and to recover particle size or composition information.

Coxiella burnetii is an intracellular pathogen that can cause both acute and chronic disease (Q fever) in humans and infects many animals with varying clinical illness and persistence. A guinea pig aerosol-challenge model of acute Q fever was developed using infection with C. burnetii across a 5-log range of challenge doses. Clinical signs included fever, weight loss, respiratory difficulty, and death, with degree and duration of response corresponding to dose of organism delivered. Histopathologic evaluation revealed coalescing panleukocytic bronchointerstitial pneumonia 7 days after a high-dose challenge, resolving to multifocal lymphohistiocytic interstitial pneumonia by 28 days. Clinical and pathologic changes noted in these guinea pigs were comparable to those seen in human acute Q fever, making this an accurate and valuable animal model. This model was used to compare the relative virulence of eight isolates from four different genotypic groups: I (RSA493, RSA334, and RSA270), IV (Q177 and Q173), V (Q212 and Q217), and VI (5J108-111). Guinea pigs infected with group I acute-diseaseassociated isolates had severe respiratory disease, while no to moderate clinical illness was observed in animals given group IV or V chronic-disease-associated isolates. 5J108- 111 appeared avirulent. These data suggest that C. burnetii isolates have a range of disease potentials and support a distinction in strain virulence between established genotypic groups, though isolates within the same genomic group cause similar pathologic responses. Heterologous protection was confirmed by cross vaccination and challenge with RSA493 and Q217. A marked non-specific suppression of lymphoproliferation was noted at 14 and 28 days post infection with RSA493; similar suppression was seen after infection with Q173 and Q212 but not 5J108-111. Proinflammatory cytokines IFN-γ and TNF-α were produced during early C. burnetii infection, at which time anti-inflammatory cytokines TGF-β and IL-10 were repressed. A vaccine made from phase I C. burnetii was found to be completely protective against lethal infection in the guinea pig model, while vaccination with killed phase II organisms conferred only partial protection, preventing death and reducing but not precluding fever and respiratory illness. Protective vaccination significantly stimulated cell-mediated immunity and elicited increases in IFN-γ, TNF-α, and IL-12p40 mRNA levels.

A Differential Mobility Analyzer/Tandem Differential Mobility Analyzer (DMA/TDMA) system was used to measure simultaneously the size distribution and hygroscopicity of the ambient aerosol population. The system was operated aboard the National Center for Atmospheric Research/National Science Foundation (NCAR/NSF) C-130 during the 2006 Megacity Initiative: Local and Global Research Observations (MILAGRO) field campaign followed by the 2006 Intercontinental Chemical Transport Experiment – Phase B (INTEX-B) field campaign. The research flights for the MILAGRO campaign were conducted within the Mexico City basin and the region to the northeast within the pollution plume. The aerosol within the basin is dominated by organics with an average measured kappa value of 0.21 /- 0.18, 0.13 /- 0.09, 0.09 /- 0.06, 0.14 /- 0.07, and 0.17 /- 0.04 for dry particle diameters of 0.025, 0.050, 0.100, 0.200, and 0.300 mu m, respectively. As the aerosols are transported away from the Mexico City Basin, secondary organic aerosol formation through oxidation and condensation of sulfate on the aerosols surface rapidly increases the solubility of the aerosol. The most pronounced change occurs for a 0.100 mu m diameter aerosol where, after 6 hours of transport, the average kappa value increased by a factor of 3 to a kappaof 0.29 /- 0.13. The rapid increase in solubility increases the fraction of the aerosol size distribution that could be activated within a cloud. The research flights for the INTEX-B field campaign investigated the evolution of the physicochemical properties of the Asian aerosol plume after 3 to 7 days of transport. The Asian aerosol within the free troposphere exhibited a bimodal growth distribution roughly 50 percent of the time. The more soluble mode of the growth distribution contributed between 67-80 percent of the overall growth distribution and had an average kappabetween 0.40 and 0.53 for dry particle diameters of 0.025, 0.050, 0.100, and 0.300 mu m. The secondary mode was insoluble with an average kappabetween 0.01 and 0.05 for all dry particle diameters. Cloud condensation nuclei closure was attained at a supersaturation of 0.2 percent for all particles within the free troposphere by either assuming a pure ammonium bisulfate composition or a binary composition of ammonium bisulfate and an insoluble organic.

The light scattering problem and its application in atmospheric science is studied in this thesis. In the first part of this thesis, light scattering theory of single irregular particles is investigated. We first introduce the basic concepts of the light scattering problem. T-matrix ansatz, as well as the null-field technique, are introduced in the following sections. Three geometries, including sphere, cylinder and hexagonal column, are defined subsequently. Corresponding light scattering properties (i.e., T-matrix and Mueller Matrix) of those models with arbitrary sizes are simulated via the T-matrix method. In order to improve the efficiency for the algorithms of single-light scattering, we present a user-friendly database software package of the single-scattering properties of individual dust-like aerosol particles. The second part of this thesis describes this database in detail. Its application to radiative transfer calculations in a spectral region from ultraviolet (UV) to far-infrared (far-IR) is introduced as well. To expand the degree of morphological freedom of the commonly used spheroidal and spherical models, triaxial ellipsoids were assumed to be the overall shape of dust-like aerosol particles. The software package allows for the derivation of the bulk optical properties for a given distribution of particle microphysical parameters (i.e., refractive index, size parameter and two aspect ratios). The array-oriented single-scattering property data sets are stored in the NetCDF format. The third part of this thesis examines the applicability of the tri-axial ellipsoidal dust model. In this part, the newly built database is equipped in the study. The precomputed optical properties of tri-axial models are imported to a polarized addingdoubling radiative transfer (RT) model. The radiative transfer property of a well-defined atmosphere layer is consequently simulated. Furthermore, several trial retrieval procedures are taken based on a combination of intensity and polarization in the results of RT simulation. The retrieval results show a high precision and indicate a further application in realistic studies.

Filter holders and continuous air monitors (CAMs) are used extensively in the nuclear industry. It is important to minimize leakage in these devices and in recognition of this consideration, a limit on leakage for sampling systems is specified in ANSI/HPS N13.1-1999; however the protocol given in the standard is really germane to measurement of significant leakage, e.g., several percent of the sampling flow rate. In the present study, a technique for quantifying leakage was developed and that approach was used to measure the sealing integrity of a CAM and two kinds of filter holders. The methodology involves use of sulfur hexafluoride as a tracer gas with the device being tested operated under dynamic flow conditions. The leak rates in these devices were determined in the pressure range from 2.49 kPa (10 In. H2O) vacuum to 2.49 kPa (10 In. H2O) pressure at a typical flow rate of 56.6 L/min (2 cfm). For the two filter holders, the leak rates were less than 0.007% of the nominal flow rate. The leak rate in the CAM was less than 0.2% of the nominal flow rate. These values are well within the limit prescribed in the ANSI standard, which is 5% of the nominal flow rate. Therefore the limit listed in the ANSI standard should be reconsidered as lower values can be achieved, and the methodology presented herein can be used to quantify lower leakage values in sample collectors and analyzers. A theoretical analysis was also done to determine the nature of flow through the leaks and the amount of flow contribution by the different possible mechanisms of flow through leaks.