The use of metallic foams as a filler in thin-walled structures can enhance their crashworthiness characteristics. It is believed that, tailoring the properties of the foam filler would enhance the effectiveness of these characteristics. This view is also supported by recent works in the literature. It is the objective of this study to examine the crush behaviour of functionally graded foam-filled tubes and evaluate the effect of discretely graded density upon the specific energy absorbed. Nonlinear parametric finite element simulations of the foam-filled tube were developed to estimate the most favourable foam density gradient in the lateral and axial directions. The effect of various design parameters such as density grading, number of grading layers, and thickness of the interactive layer upon the resulting specific energy absorption was investigated. The results show that the specific energy absorption of a tube filled with functionally graded foam is better than uniform density foam.

Resources such as energy and water are forecasted to become scarcer in the future. The traditional engineering approach for dealing with this problem can be compromised by the rebound effect. Therefore, it is important that we design products that also encourage users to engage in pro-environmental behaviours, also known as environmentally significant behaviours (ESB). Lead-user theory was first applied to the problem of ESB, resulting in the discovery that resources, when presented in discrete instead of continuous form, enable conservation. The principle was verified empirically. A method was developed to help designers develop products that implement the discretization principle without compromising user needs. Affordance theory was also applied to the problem of ESB. Two methods, one to expedite the finding of affordances and the second to change a product’s affordances to enable ESB, were developed. The application of design theory and techniques to the ESB problem shows promise.

In this work, a MFC fabrication procedure including two non-conventional techniques (partial baking and cap-sealing) were employed for the development of an up-scaled microfluidic fuel cell (MFC). Novel carbon-based electrode materials were employed, including carbon foam, fibre, and cloth, the results from which were compared with traditionally-employed carbon paper. The utilization of carbon cloth led to 15% of the maximum power that resulted from carbon paper; however, carbon fibre led to a 24.6% higher power density than carbon paper (normalized by electrode volume). When normalized by projected electrode area, the utilization of carbon foams resulted in power densities up to 42.5% higher than that from carbon paper. The impact of catalyst loading on MFC performance was also investigated, with an increase from 10.9 to 48.3 mgPt cm-2 resulting in a 195% increase in power density.

In this thesis, two numerical modeling methods are used to investigate the thermal conductivity of the polymer electrolyte membrane (PEM) fuel cell gas diffusion layer (GDL). First, an analytical model is used to study the through-plane thermal conductivity from representative physical GDL models informed by microscale computed tomography imaging of four commercially available GDL materials. The effect of the heterogeneity of the through-plane porosity of the GDL and polytetrafluoroethylene (PTFE) treatment is studied and it is noted that the high porosity surface transition regions have a dominating effect over the addition of PTFE in impacting the overall thermal conductivity. Next, the lattice Boltzmann method (LBM) is employed to study both the in-plane and through-plane thermal conductivity of stochastic numerically generated GDL modeling domains. The effect of GDL compression, binder content, PTFE treatment, addition of a microporous layer (MPL), heterogeneous porosity distributions, and water saturation on the thermal conductivity are investigated.

Biomass fast pyrolysis liquid is a renewable fuel for stationary heat and power generation; however degradation of bio-oil by time, a.k.a. aging, has an impact on combustion performance and emissions. Moreover, the temperature at which bio-oil is stored has a strong effect on the degradation process. In this study, the same biooil-ethanol blends with different storage conditions are tested in a pilot stabilized spray burner under the same flow conditions. Measurements were made of the steady state gas phase emissions and particulate matter, as well as visual inspection of flame stability. The results confirm a relationship between room temperature storage time and storage at higher temperatures (accelerated aging). They also show that fuel aging increases the emissions of carbon monoxide, unburned hydrocarbon and the organic fraction of particulate matter. These emissions increase more rapidly as more time is allocated for aging. NOx emission shows a slight decrease with fuel aging.

Manufacturers face the challenge of enhancing fuel efficiency, engine performance, and reducing harmful emissions. Novel fuel injection technologies can assist in meeting such demands. This dissertation summarizes the stages in the design, prototyping and experimental analysis of a direct-acting piezoelectric fuel injector concept. In the proposed design, a piezoelectric stack actuator is used to directly control the injection of fuel in order to enhance the injection characteristics by utilizing the fast response time of the actuator. The direct-acting concept was implemented by developing a motion inverter in the form of a disc that reverses the direction of the input and allows the actuator to directly control injections. Tests with input signals similar to those used in diesel engines confirmed the theoretical calculations and verified the prototype’s performance. This design can control the quantity of injected fuel more precisely than currently available commercial injectors.

In the developing world, there are large populations suffering from infectious diseases, many of whom are located in remote regions. With the rapid growth in microfluidic systems in recent years, complex functions of conventional diagnostic equipment have been miniaturized and integrated into small devices at the size of a credit card (so-called portable Point-of-care (POC) devices). In this thesis a novel approach to overcoming the challenge of in-field biological sample processing and preparation to produce high quality fluids that can be readily used for downstream testings is described and proof of concept experiments presented. This approach uses hydrodynamic effects and combines nanoporous membrane with microfluidic systems and to filter the cellular component of blood. Experiments presented here demonstrate successful cells filtration from whole blood. Employing hydrodynamic effects is also shown to be an effective and potentially useful technique to isolate cells and plasma within appropriate micro-architectures.

Laser scanning cytometry (LSC) is a slide-based method that is used clinically for Quantitative Imaging Cytometry (QIC). A “Clatch” slide, named after the inventor, which is used in conjunction with the LSC for immunophenotyping patient cell samples, has several drawbacks. The slide requires time consuming and laborious pipette steps, making the slide prone to handling errors. The Clatch slide also uses a significant amount of cell sample, limiting the number of analyses for fine needle aspirate (FNA) samples. This thesis details an automated microfluidic system, composed of an embedded circuit, a plastic and polymer microfluidic device, and an aluminum frame, which can perform the same immunophenotyping procedures. This new system reduces the labor from 36 pipette steps to 8, it reduces the amount of cell sample from 180 μL to 56 μL, and it shortens the entire procedure from 75 minutes to 42 minutes.

The use of metallic foams as a filler in thin-walled structures can enhance their crashworthiness characteristics. It is believed that, tailoring the properties of the foam filler would enhance the effectiveness of these characteristics. This view is also supported by recent works in the literature. It is the objective of this study to examine the crush behaviour of functionally graded foam-filled tubes and evaluate the effect of discretely graded density upon the specific energy absorbed. Nonlinear parametric finite element simulations of the foam-filled tube were developed to estimate the most favourable foam density gradient in the lateral and axial directions. The effect of various design parameters such as density grading, number of grading layers, and thickness of the interactive layer upon the resulting specific energy absorption was investigated. The results show that the specific energy absorption of a tube filled with functionally graded foam is better than uniform density foam.

In this work, a MFC fabrication procedure including two non-conventional techniques (partial baking and cap-sealing) were employed for the development of an up-scaled microfluidic fuel cell (MFC). Novel carbon-based electrode materials were employed, including carbon foam, fibre, and cloth, the results from which were compared with traditionally-employed carbon paper. The utilization of carbon cloth led to 15% of the maximum power that resulted from carbon paper; however, carbon fibre led to a 24.6% higher power density than carbon paper (normalized by electrode volume). When normalized by projected electrode area, the utilization of carbon foams resulted in power densities up to 42.5% higher than that from carbon paper. The impact of catalyst loading on MFC performance was also investigated, with an increase from 10.9 to 48.3 mgPt cm-2 resulting in a 195% increase in power density.