The investigation of exotic particle capture in complex media is studied in this thesis. An investigation into the best one-step Born-type approximation for the Auger capture rate of mu-is made for a H target. It is concluded that a distorted Born-approximation in which the shielding effect of the atomic electrons is included in the determination of the Coulomb continuum wavefunctions is the most appropriate and computationally efficient method of calculation. Generalisation of this method for Auger capture in light atoms is then studied with the ejection of 1s, 2s, 2p, 3s and 3p electrons examined. The focus of the investigation is on the dependence of the Auger rate on the type of electron, the final mu-bound state, and the collision centre of mass energy. It is discovered that the outermost electrons of an atom are the most effective capture electrons with Auger rate maxima as a function of the principal quantum number n occurring at approximately n = 14, n = 30 and n = 40 for the K, L and M-shell s and p electrons. The Auger rate curves as a function of the angular momentum I reach a maximiim between I = 10 and I = 20 dropping rapidly thereafter. An attempt is also made at predicting pi-Auger capture rates into (pppi-)+ molecular orbitals, however the results are schematic and serve only as an example of the method of calculation. Differences between the initial distributions required by the cascade code EXCAS to fit the X-ray data from essentially atomic targets and molecular targets have been determined. A modified statistical distribution with small positive a's is required for the noble gas atoms with a very highly ionised atom resulting at the n = 14 stage for mu-. The oxygen and carbon atoms in simple molecules require a small negative a with again a depleted electron population at the n = 17 stage for pi-. By extending the cascade code EXCAS to larger starting values and inputing a population of mu- for every bound quantum state the properties and de-excitation behaviour of the Ne muonic atom is studied. Results show that depending upon if electron refilling rates are fast or slow an approximate modified distribution with a positive a at the n = 14 state can be attained by a statistical input distribution of mu- or a distribution peaked in I around I = n/2 respectively. The second distribution agrees with the previous results for Auger capture in light atoms.

There are many instances where fluid and particles traveling through a narrow passage, such as a crack in a window or door, have large but sometimes unseen effects on our daily lives. For instance, in the cold months of the year a pressure gradient can exists between the inside and outside of a building which causes cold, outdoor air to flow inside through any cracks; significantly decreasing heating efficiency. This inflow of atmospheric air can bring with it dangerous contaminant particles to the inside of a building. Pollution can also occur inside a structure from internal sources of contamination, such as smoke generation from a fire. This thesis represents a two-fold examination of these phenomena. The first part of the thesis showcases a method for local measurement of air leakage flow rate, which can be used to quickly assess leakage rates across a surface, such as a window. The method uses a small local enclosure with constant volume placed about a region on the structure under investigation, which is depressurized and injected with a small concentration of carbon dioxide as a tracer gas. The time variation of the pressure and carbon dioxide concentration inside the enclosure are monitored and used to quantify the leakage flow rate as a function of pressure difference. Because of the small size of the enclosure, advanced data processing techniques are necessary to reduce uncertainty in determination of the rate of change of the carbon dioxide concentration that arises from sensor variability. Results of a laboratory demonstration of the proposed leakage detection and characterization device are reported for the problem of leakage through a circular hole in a plate with prescribed pressure differences. Experimental results from the laboratory tests are found to be in excellent agreement with results of a numerical simulation of leakage flow through a hole, as well as predictions from a number of empirical equations for this problem found in the literature. The second part of the thesis is a numerical study of particle capture in the entrance region of a crack, which is a phenomenon previously not well understood or accounted for in empirical correlations. The computational domain for laminar flow through a crack consists of the crack channel and both inlet and exit reservoirs that are much larger than the channel width. The simulations examined different mechanisms for particle capture within the channel entrance region, including collision on the inlet reservoir wall just outside the crack channel, collision within the crack channel due to cross-stream inertia imparted by the entrance flow, collision induced by Brownian diffusion both on the inlet reservoir wall outside of the channel and within the channel, and gravitational collision within the channel. A detailed study of the variation of the entrance penetration factor with parameters such as the Stokes, Peclet, and Froude numbers was performed, and comparison of the numerical predictions with different theoretical expressions were made when the latter were available. Validity of the assumption of penetration factor independence was also examined for cases where both entrance region inertia and gravitational settling are significant.

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