ENV-644: USE OF NEW MODELS TO SUPPORT VAPOUR INTRUSION MITIGATION DESIGN

Soil vapour intrusion of subsurface volatile organic compounds (VOCs) into indoor air of buildings is a significant potential concern at existing sites where chemical releases occur, or at new buildings at Brownfield sites with residual chemical impacts. While soil vapour intrusion mitigation systems are increasingly being implemented, there are limited published data on mitigation performance for VOCs particularly for industrial or commercial buildings or high density residential buildings with below ground parking garages. Data gaps include the effectiveness of passive and active venting systems and reduction in vapour intrusion that can be achieved relative to unmitigated buildings. Because of lack of knowledge and standardization, design practices and post-mitigation monitoring requirements vary widely and are, in some cases, over-conservative. To address these gaps, a comprehensive empirical review of data on the performance of active and passive venting systems and a study using the Modified Johnson and Ettinger Model was completed. The empirical data indicate performance of passive venting systems are variable in terms of venting air flow rates and pressures. The results of modelling for passive venting indicate a wide range of predicted reduction factors, defined as the vapour attenuation factor for a baseline unmitigated building divided by the attenuation factor for the mitigated case. Because of the potential for depressurized buildings and/or reverse vent stack effect, for passive venting systems a continuous leak free barrier that reduces the potential for soil gas diffusion and advection is essential. The performance of active venting systems can be more readily controlled and quantified based on design principles as supported by the results of modelling, which indicated higher reduction factors than for passive venting systems. For both passive and active venting systems, improved efficiency in venting can be achieved through aerated subfloors. A monitoring framework that is robust but efficient and sustainable is presented that incorporates the concept of a concentration exceedance factor and the type of mitigation system

A research on the use of metaphor design in promoting brand identity

Every new brand which competes and increases its market share needs some tools and methods to be applied to its products. The objective of this research is to investigate the use of metaphor as a tool for peak shift effect and its impact on memory, which can be effective in promoting brand identity from a customer perspective. In this respect, this research uses a combination of memory test and comparison of two objects method. Therefore, the research method was according to environment specifications. The results indicated that the products having metaphor in comparison to products with no metaphor has an effective role in peak shift and image persistence and its name in user’s mind. In conclusion, the brand identity can be promoted in a variety of ways, among which the design of metaphor, which is related to product design and graphic design, is one of these ways

A theoretical model of NMR surface relaxation in porous media

A model has been developed to express the relaxation time constant of pore water hydrogen protons in porous geological materials. This model is based on the dipolar interactions of the protons with the naturally found paramagnetic ions near the surface of the solid, modulated by the diffusive motion of the pore water molecules. The effect of a uniform nonmagnetic coating on the solid, which physically separates the water molecules from the paramagnetic ions, is incorporated in the developed model of surface relaxation rate, 1/T1S. A three-dimensional model pore space is defined as a rectangular prism in a sheet-like pore structure. The motion of the molecules is described as two-dimensional diffusion parallel to the solid pore walls, and one-dimensional diffusion perpendicular to the surfaces. The dipolar interaction is considered between hydrogen protons associated with the water molecules, and a layer of randomly distributed paramagnetic ions on the solid. The protons' distance of closest approach to the layer of paramagnetic ions is determined by the thickness of substance coating the solid surface. The resulting expression for 1/T1S involves a number of parameters, some of which can be eliminated by considering the normalized relaxation rates: 1/T1S for the coated sample divided by that of the uncoated sample. Other unknown parameters are used to set bounding limits on the predicted normalized relaxation rates, T1S(plain)/T1S(coated). The predicted trend in T1S(plain)/ T1S(coated) with increasing coating thickness can be approximated by a logarithmic decline for thicknesses up to 2nm. This predicted decay in normalized relaxation rate with increasing coating thickness is more gradual than the trend predicted by previous models. As a result, the application of the developed model to measured relaxation times reported in studies of coated and plain samples is capable of providing realistic estimates of coating thicknesses. [Scientific formulae used in this abstract could not be reproduced.]Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat

Methane Transport during a Controlled Release in the Vadose Zone

Shallow, small-rate releases of ethanol-blended fuels from underground storage tanks (USTs) may be quite common and result in subsurface CH generation. However, vadose zone transport of CH generated from these fuel releases is poorly understood, despite the potential to promote vapor intrusion or create explosion hazards. In this study, we simulated shallow CH generation with a controlled subsurface CH release from July 2014 to February 2015 to characterize subsurface CH migration and surface emissions and to determine environmental controls on CH fate and transport. July 2014 through November 2014 was an extended period of drought followed by precipitation during December 2014. Throughout the experiment, under varied CH injection rates, CH formed a radially symmetrical plume around the injection point. Surface efflux during the drought period of the experiment was relatively high and stable, with approximately 10 to 11 and 34 to 52% of injected CH reaching the ground surface during the low- and high-rate injections, respectively. Following the period of precipitation and increased soil moisture, efflux dropped and stabilized at approximately 1% of injected CH, even as soil moisture began to decrease again. Tracer and inhibitor experiments and estimates of soil diffusivity suggest that microbial CH oxidation was responsible for the observed drop in efflux. The decrease in efflux only after soil moisture increased suggests a strong environmental control over the transport and oxidation of vadose zone CH