The Comprehensive Nuclear Test Ban Treaty verification regime mandates atmospheric monitoring for the four radioxenon isotopes that are produced in high abundance in a nuclear explosion: [superscript 131m]Xe, [superscript 133m]Xe, [superscript 133g]Xe, and [superscript 135g]Xe. This mandate has driven the development of improved xenon detectors, including a phoswich detector, which has potential to replace the ARSA detector in the International Monitoring System. In this experiment, the four relevant radioxenon isotopes were produced through neutron activation and the phoswich detector was used to attain spectra from the gas. Spectral characteristics and resolution of the phoswich spectra were compared to an ARSA-type [beta]-[gamma] coincidence detector to perform an overall evaluation of the phoswich detector. The results indicated that spectral characteristics and resolutions for the phoswich were comparable to the ARSA-type detector, with slightly improved beta detection. As an additional test of the new detector's capabilities, a tailored spectrum designed to mimic a nuclear explosion signature was produced and analyzed with the detector. / text

Explosions of gas and dust continue to be recognized as an extreme danger in underground coal mines and still occur despite significant technological advances. Mining researchers have been attempting to accurately measure and quantify ventilation and gas properties since early mining; however basic monitoring attempts were limited by the available technologies. Recent advancements in monitoring and communication technologies enable comprehensive atmospheric monitoring to become feasible on a mine-wide scale. Atmospheric monitoring systems (AMS) allow operators to monitor conditions underground in real-time. Real-time monitoring enables operators to detect and identify developing high risk areas of the mine, as well as quickly alert mining personnel underground. Real-time monitoring also can determine whether conditions are safe for mining, to operate ventilation systems more efficiently, and to provide an additional layer of monitoring atmospheric conditions underground. AMS utilizes numerous monitoring technologies that will allow underground coal mines to comprehensively monitor gas and ventilation parameters. AMS are utilized worldwide as well as in the United States, and can be modified to cater to specific hazards at different mines. In the United States, AMS are primarily used to monitor belt lines and electrical installations for smoke, CO, and CH₄, and to automatically alarm at set thresholds. The research in this study investigates and analyzed AMS across the world (specifically Australia, Canada, and United States). Two case studies presented in Chapter 5 focus on the utilization and implementation of AMS in two underground coal mines in the United States. These case studies identify challenges regarding installation, data management, and analysis of real-time atmospheric monitoring data. The second case study provides significant evidence that correlates mine ventilation fan outages and changes in barometric pressure to increases in methane from previous works. This research does not attempt to quantify data, but intends to provide engineers knowledge to utilize, design, and implement an AMS. Several incident scenarios are simulated using ventilation computer software, as well as the benefits of monitoring in past disasters are analyzed. This research does not intend to place blame, but intends to increase the understanding of utilizing and implementing AMS in underground coal mines. / Ph. D.

A majority of underground coal mine disasters in the United States are due to explosions. Current atmospheric monitoring system (AMS) practices in the US could be enhanced to facilitate data sharing and learning of the entire work force. With the inclusion of additional atmospheric monitoring and data collecting, meaningful analysis can be realized and shared with the workforce. AMS data can be utilized to advance the understanding of underground atmospheres for the entire workforce along with adding to the knowledge base for preventative planning. An AMS interface ADAMAS is suggested to facilitate this conglomeration and sharing of the data visually, so that it can be quickly processed and applied in their daily decisions. An emerging sensor technology for underground mining, fiber optics is explored and tested in emergency, or fire and explosion situations. The fiber optic methane sensor performed well in smoke only showing a slow in response time due to soot on the filter. The ADAMAS interface was tested in a large population of underground coal miners. The population varied in age, job, classification, and experience. They all primarily found it to be easy to use and helpful to them. Concerns arose when asked how this will facilitate an improved relationship with regulatory agencies. There is trepidation when it comes to additional atmospheric information sharing, that it may not be used advance understanding of mine atmospheres. The AMS data collected is individual to each mine site but can assist in the understanding of underground atmosphere as a whole. Moving forward, regulatory bodies should use this as a stepping point to consider how this information can be used to advance the field of mine ventilation and also the health and safety of the miner. / Ph. D.

Atmospheric monitoring is a vital part of environmental management. Monitoring temporal changes in atmospheric pollution on a local, regional and global scale is important in order to mitigate adverse effects on health and the environment. Currently there is general agreement that atmospheric pollution should be monitored, however, less emphasis is often placed on what should be achieved and the specific monitoring that should be included. Atmospheric pollution monitoring is often hampered by geographically restricted and site specific effects resulting in inefficient or ineffective information transfer to the local manager. The scientific community in the developed world often underestimate problems associated with the maintenance of comprehensive atmospheric measurement stations in Africa. A holistic approach is needed to optimise atmospheric monitoring according to specifications set out by system design; this includes site selection, site design, maintenance and quality control. The aim of this dissertation is to apply the Systems Engineering approach to a case study, the Welgegund atmospheric measurement station (WAMS), to offer a holistic view of interaction between different operational systems and the complexity behind their management in order to be informative to students and personnel from a non-engineering background. A knowledge gap exists that links practical industry related sciences such as engineering to more fundamental and theoretical sciences. In this dissertation the customer need was determined and an operational concept was developed for the WAMS system. The high level goals of the WAMS were derived and stated as applicable to other new as well as established measurement stations. Technical and fundamental requirements such as trained staff for appropriate logistical support and a broad spatial coverage of air quality monitoring were identified. The system boundaries and operational constraints were established for the WAMS, exposing weaknesses and proposing solutions to ensure long term sustainability. Weaknesses include irregular funding periods and retention of expertise (trained students leave academia for industry) whereas a possible solution included overlapping projects and contracts. Functional analysis highlighted the design and establishment process of the WAMS. Physical architectures and interfaces were explored and finally the success of the establishment of the WAMS was evaluated by a reliability block diagram. The reliability of the WAMS system was calculated to be 96.6 %. This agrees well with the percentage data coverage calculated for the gaseous (95.9 %), aerosol (93.4 %) and meteorological (94.6 %) systems (15 min averages). The reliability of the national grid to supply power to the WAMS was found to be the main restrictive component. It may be a challenge interacting and coordinating projects with different disciplines, branches or sectors outside of a speciality project. This study has bridged the gap between industry related sciences such as engineering to more fundamental and theoretical sciences. A framework has been provided that highlights the techniques of Systems Engineering and provides an understanding for the need and process of atmospheric monitoring. / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2015

Atmospheric monitoring is a vital part of environmental management. Monitoring temporal changes in atmospheric pollution on a local, regional and global scale is important in order to mitigate adverse effects on health and the environment. Currently there is general agreement that atmospheric pollution should be monitored, however, less emphasis is often placed on what should be achieved and the specific monitoring that should be included. Atmospheric pollution monitoring is often hampered by geographically restricted and site specific effects resulting in inefficient or ineffective information transfer to the local manager. The scientific community in the developed world often underestimate problems associated with the maintenance of comprehensive atmospheric measurement stations in Africa. A holistic approach is needed to optimise atmospheric monitoring according to specifications set out by system design; this includes site selection, site design, maintenance and quality control. The aim of this dissertation is to apply the Systems Engineering approach to a case study, the Welgegund atmospheric measurement station (WAMS), to offer a holistic view of interaction between different operational systems and the complexity behind their management in order to be informative to students and personnel from a non-engineering background. A knowledge gap exists that links practical industry related sciences such as engineering to more fundamental and theoretical sciences. In this dissertation the customer need was determined and an operational concept was developed for the WAMS system. The high level goals of the WAMS were derived and stated as applicable to other new as well as established measurement stations. Technical and fundamental requirements such as trained staff for appropriate logistical support and a broad spatial coverage of air quality monitoring were identified. The system boundaries and operational constraints were established for the WAMS, exposing weaknesses and proposing solutions to ensure long term sustainability. Weaknesses include irregular funding periods and retention of expertise (trained students leave academia for industry) whereas a possible solution included overlapping projects and contracts. Functional analysis highlighted the design and establishment process of the WAMS. Physical architectures and interfaces were explored and finally the success of the establishment of the WAMS was evaluated by a reliability block diagram. The reliability of the WAMS system was calculated to be 96.6 %. This agrees well with the percentage data coverage calculated for the gaseous (95.9 %), aerosol (93.4 %) and meteorological (94.6 %) systems (15 min averages). The reliability of the national grid to supply power to the WAMS was found to be the main restrictive component. It may be a challenge interacting and coordinating projects with different disciplines, branches or sectors outside of a speciality project. This study has bridged the gap between industry related sciences such as engineering to more fundamental and theoretical sciences. A framework has been provided that highlights the techniques of Systems Engineering and provides an understanding for the need and process of atmospheric monitoring. / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2015

Cosmic rays of energies above 1014 eV are detected mostly indirectly, by observing the extensive air showers they create in the atmosphere. Multiple experiments suggest that the current models of high-energy interactions do not describe the cosmic ray data perfectly, in particular when it comes to the prediction for the number of muons at ground. We present two models aiming to improve the description of the muon component, one based on the addition of particles with small momenta in the local center-of-mass frame of the high-energy hadronic interactions in the shower, the other on the addition of the so-called dark photons to the electromagnetic part of the shower. While we find the latter having no observable consequences, the former improves the agreement between observed and predicted amounts of muons both for the DELPHI cosmic ray data and for the measurements by the Pierre Auger Observatory. We also describe the FRAM telescope, a device used to monitor the atmosphere at the Pierre Auger Observatory, and its applications to the search for anomalous shower profiles and to the measurement of the aerosol content of the atmosphere, which is crucial for the analysis of data obtained by fluorescence detectors. 1

Cette thèse touche à la problématique des échanges de gaz aux interfaces entre la géosphère, la biosphère, l'hydrosphère et l'atmosphère par l'intermédiaire du monitoring géochimique des gaz appliqué aux sites de stockage géologiques du CO2. Au niveau de l'axe « Métrologie », nous avons développé une plate-forme de monitoring géochimique continu, in situ et déportée par spectrométrie FTIR/Raman pour la mesure des gaz du sol (CO2, CH4, N2, O2, H2O). Des protocoles de quantification ont été développés pour la mesure par télédétection infrarouge terrestre en mode passif du CO2, CH4, SO2, H2S dans l'atmosphère. Au niveau des axes « Monitoring » et « Modélisation », les mesures de gaz du sol à proximité du puits d'injection de Rousse (Pilote CO2 Total, Lacq/Rousse, France) sur plus de sept cycles saisonniers ont montré une anti-corrélation entre la teneur en CO2 et les variations du niveau piézométrique de la nappe. Cette relation a permis de modéliser l'enveloppe de variabilité « naturelle » de la teneur en CO2 dans le sol, qui constitue un élément clé pour la surveillance des sites de stockage. Les variations majeures de teneur en CO2 sont attribuées à des processus de dissolution/libération de CO2 par la nappe, jouant un rôle de pompe à CO2. La concentration en CO2 en surface (+1m) serait gouvernée par les variations de teneur en CO2 du sol. Les mesures par télédétection FTIR des gaz dans l'atmosphère ont permis d'établir pour la première fois une simulation expérimentale 3D des enveloppes de CO2 à l'aplomb du site d'injection. Ces résultats constituent un premier pas vers la mise en place d'un outil de surveillance des panaches gazeux dans l'atmosphère / This study is based on the problematic of gas exchanges at the interface between the geosphere, biosphere, hydrosphere and atmosphere through the geochemical monitoring of gas applied to CO2 geological storage sites. Concerning the "Metrological" aspect, we developed and implemented an in situ continuous geochemical monitoring station, based on coupling FTIR/ Raman spectrometry for measuring soil gas (O2, N2, CO2, CH4 and H2O) close to the injection wells of Rousse 1 (CCS Total pilot, Lacq-Rousse, France). We also developed protocols to identify and quantify CO2, CH4, SO2, H2S in the atmosphere (plume) by passive remote sensing FTIR. On the "Monitoring" and "Modelling" aspects, the continuous recording of soil CO2 concentration during more than 7 seasonal cycles indicate that CO2 concentration in the soil was anti-correlated with changes in piezometric level of the groundwater. This correlation was used to model the limits of natural variability of CO2 content in the soil, which is a key to CCS sites monitoring. The main fluctuations in soil CO2 content was assigned to a dissolution/release process of CO2 by the perched water table, acting as a CO2 pump. The CO2 concentration at the near surface (+ 1 m) would be governed by changes of the soil CO2 content. FITR remote sensing measurement of atmospheric gases allowed for the first time to perform an experimental 3D simulation of CO2 layers on the injection site. This type of experimental simulation is a first step for the monitoring of gases in the atmosphere

Nano-particle aerosols are one of the major types of air pollutants in the urban indoor and outdoor environments. Therefore, determination of mechanisms of formation, dispersion, evolution, and transformation of combustion aerosols near the major source of this type of air pollution - busy roads and road networks - is one of the most essential and urgent goals. This Thesis addresses this particular direction of research by filling in gaps in the existing physical understanding of aerosol behaviour and evolution. The applicability of the Gaussian plume model to combustion aerosols near busy roads is discussed and used for the numerical analysis of aerosol dispersion. New methods of determination of emission factors from the average fleet on a road and from different types of vehicles are developed. Strong and fast evolution processes in combustion aerosols near busy roads are discovered experimentally, interpreted, modelled, and statistically analysed. A new major mechanism of aerosol evolution based on the intensive thermal fragmentation of nano-particles is proposed, discussed and modelled. A comprehensive interpretation of mutual transformations of particle modes, a strong maximum of the total number concentration at an optimal distance from the road, increase of the proportion of small nano-particles far from the road is suggested. Modelling of the new mechanism is developed on the basis of the theory of turbulent diffusion, kinetic equations, and theory of stochastic evaporation/degradation processes. Several new powerful statistical methods of analysis are developed for comprehensive data analysis in the presence of strong turbulent mixing and stochastic fluctuations of environmental factors and parameters. These methods are based upon the moving average approach, multi-variate and canonical correlation analyses. As a result, an important new physical insight into the relationships/interactions between particle modes, atmospheric parameters and traffic conditions is presented. In particular, a new definition of particle modes as groups of particles with similar diameters, characterised by strong mutual correlations, is introduced. Likely sources of different particle modes near a busy road are identified and investigated. Strong anti-correlations between some of the particle modes are discovered and interpreted using the derived fragmentation theorem. The results obtained in this thesis will be important for accurate prediction of aerosol pollution levels in the outdoor and indoor environments, for the reliable determination of human exposure and impact of transport emissions on the environment on local and possibly global scales. This work will also be important for the development of reliable and scientifically-based national and international standards for nano-particle emissions.