Until present, many researchers relied on the conventional plug flow dispersion models to analyse the concentration profiles obtained from the tracer injection experiments to evaluate the dispersion coefficients in packed beds. The Fickian concept in the limit of long time duration is assumed to be applicable and it implies that the mean-square displacement of the tracer profile is constant with time and the concentration profile is Gaussian. There were very few studies on identifying the conditions under which this assumption is valid and delineate the range of applicability of the existing plug flow dispersion models. If the time scales of a tracer injection experiment are not sufficient for a tracer to traverse the bed radius and sample the velocity variations, this could give rise to persisting non-Fickian transients where the mean-square displacement of the tracer profile is not constant with time and the concentration profile deviates from the normal Gaussian distribution. These transients cannot be predicted by the conventional plug dispersion models. An extended axial non-Fickian macroscopic dispersion model is derived to describe the transient development of a solute tracer when injected into a fluid flowing through a cylindrical packed bed or empty tube and some non-Fickian effects in the dispersion process. The flow profile in beds packed with uniform particles exhibits radial non-uniformity due to the oscillatory variation in porosity because of the wall confinement (wall effect). Compared with the axial plug flow dispersion model, the extended model contains time-dependent coefficients such as the transient axial dispersion coefficient and higher order derivatives (higher than second order) of the cross-sectionally averaged concentration. Including them provides some insight on non-Fickian transport in the dispersion process. The model provides time criteria on the basis that the effelongitudinal dispersion coefficient in the packed bed reaches its asymptotic value and the non-Fickian transients will die out. Some experimental conditions in the literature were checked by these criteria and found to be either marginally satisfied, or not satisfied at all, which indicates that the Fickian concept is not valid. The model results for tracer dispersion in cylindrical packed beds show that the longitudinal dispersion coefficient converges to its asymptotic value on a time scale proportional to R2/(DT) where R is the column radius and (DT) is the area averaged lateral dispersion coefficient. The extended model encouraged study of the consequences of the additional dispersion terms in other applications such as the pulse spread in the field of capillary column inverse gas chromatography (CCIGC). CCIGC is used to evaluate the solute-polymer diffusion coefficient Dp and the partition coefficient K at infinite dilute conditions. The tube geometry in CCIGC is more complex than the conventional Taylor dispersion problem due to the polymer coating on the inside of the capillary wall. The extended CCIGC model presented in this study has advantages over the previous models by including the effects of Taylor dispersion and higher order derivatives of the pulse area-averaged concentration. Taylor dispersion effect causes more pulse spread in the longitudinal direction and by not including it in the CCIGC regression models may cause a significant error in the measured Dp values. The extended CCIGC model provides for the first time criteria on capillary dimensions for the transient coefficients (multiplying the second and higher order derivatives) to become constant and for the non-Fickian effects associated with the higher order derivatives to be neglected. Model results show that Taylor dispersion effect has a significant effect on the elution profiles at high values of Dp and/or low values of gas diffusion coefficients Dg and it can be used to increase the sensitivity range of the previous CCIGC models at extremely low and high Dp values.

<p>Wave power is renewable energy which is environmentally friendly. Unlike most of renewable energy resources, wave energy can produce power all the year. The wave energy is stored in the ocean worldwide and highly concentrated near the ocean surface. It can be captured by wave power devices. Wave power is considered as a competitive energy resource in future.</p><p> <strong></strong></p><p>Waves are generated by wind blows across the surface of sea. Wave energy is one kind of mechanical energy which will be used for electricity generation. Wave power can’t be used directly to generate electricity; at first the wave energy is converted into the other form of useful mechanical energy and then converted into electricity. Wave power has a high potential to be captured and used for generating electricity in future as the technology develops further.</p><p> </p><p>Wave energy has been used since 1890s. There is a lot of energy stored in waves. 94% energy of the ocean stored in the wave, and the other 6% is tidal energy.  Only small a part of the wave power is used for commercial electricity generation today.</p><p> </p><p>The China is a developing country with a very large population which annually consume about 3073TWh electricity of which 496TWh is from renewable energy.  The wave power was less than 1GWh in 2007 (reference from International Energy Agency). The World Energy Council has measured the total useful power of the ocean wave energy to be more than 2TW in the world and corresponding to 6000TWh per year. There is about 70GW useful wave power resources in China, equivalent to an annual useful wave power resource of 200TWh.</p><p> </p><p>The lowest capital cost for the wave power system is today around 0.1Euro/kWh. China will in the future focus on the development electricity generation by wave power. There will be hundreds of new wave power plant built in China during the next twenty years, and the total installed capacity will be larger than 1GW at 2030, which delivers 3TWh annually. This corresponds to less than 1 percent of the total use of electricity in China.</p><p> </p><p>This thesis focuses on the functionality, efficiency and economic pay-off of existing ocean wave power systems, as well as how easy the ocean wave power can produce electricity. Firstly it discusses the physical concepts of wave power, and then focus on the existing wave power systems around the world. It is concluded from the Chinese sea characteristics and the designed conditions of different wave power systems, that the Pelamis and Oyster wave power converters are the best suitable systems for China.</p>

The separating characteristics of high performance liquid chromatography (HPLC) columns, measured in terms of the height equivalent of a theoretical plate (HETP) and skewness of the eluted peak, are investigated using computational fluid dynamics (CFD). Gradually expanding and contracting sections are introduced at the inlet and outlet, respectively, in columns with and without frits and their performance was compared with that of the conventional columns without expanding and contracting regions. / Singapore-MIT Alliance (SMA)

The goal of this thesis is to introduce new methods to create intricate perforated shapes in a computing environment. Modeling shapes with a large number of holes and handles, while requiring minimal human interaction, is an unsolved research problem in computer graphics. In this thesis, we have developed two methods for interactively modeling such shapes. Both methods developed create perforated shapes by building a framework of tube like elements, such that each edge of a given mesh is replaced by a pipe. The first method called Wire modeling replaces each edge with a pipe that has a square cross-section. The result looks like a shape that is created by a framework of matchsticks. The second method, called Column modeling allows more rounded cross-sections for the pipes. The cross-sections can be any uniform polygon, and the users are able to control the number of the segments in the cross-section. These methods are implemented as an extension to an existing modeling system guaranteeing that the pipes are connected and the resulting shape can be physically constructed. Our methods require an initial input mesh that can either be imported from a commercially available software package, or created directly in this modeling system. The system also allows the users to export the models in obj file format, so that the models can be animated and rendered in other software packages.

Microfluidic chips have gained wide applications in various fields, including medicine, environmental sciences and forensic investigations. They are used for the separation of proteins, blood, bacterial cell suspensions, antibody solutions, and drugs. Microfluidic chips display significant advantages, which include faster analysis time, reduced amounts of samples and reagents volumes, flexibility in design and increased separation efficiency. Whole column imaging detection (WCID) exhibits significant advantages compared to other detection methods that are widely used for detecting analytes after the separation of these analytes using isoelectric focusing. With these other methods, there is a need to mobilize the focused sample bands past the detector after separation but with WCID, there is no need for mobilization step. The aim of this research is further development of WCID by characterizing microfluidic chips fabricated for the detection system, to enhance its detection so that high efficiency can be obtained. The chips were fabricated using soft lithography technology at the Microfluidic laboratory, University of Waterloo and they were used to perform isoelectric focusing of various proteins in our laboratory. The fabricated chips with straight channel design were used to carry out isoelectric focusing of some proteins and the results obtained were compared with the results obtained using commercial cartridges. The chips with tapered channel design were used to carry out isoelectric focusing of proteins in which thermally generated pH gradient principle was employed. The samples after separation were sprayed into a mass spectrometer using nano-electrospray interface to obtain their molecular masses. Compatible cartridges for nano-electrospray mass spectrometer were developed and these cartridges were used to carry out capillary isoelectric focusing of low molecular pI markers and proteins. These cartridges were also connected to the nano-electrospray mass spectrometer to obtain the mass to charge ratios of some proteins. The fabricated microfluidic chips with straight channel design were also used to investigate the interaction between drugs and protein.

Wave power is renewable energy which is environmentally friendly. Unlike most of renewable energy resources, wave energy can produce power all the year. The wave energy is stored in the ocean worldwide and highly concentrated near the ocean surface. It can be captured by wave power devices. Wave power is considered as a competitive energy resource in future.   Waves are generated by wind blows across the surface of sea. Wave energy is one kind of mechanical energy which will be used for electricity generation. Wave power can’t be used directly to generate electricity; at first the wave energy is converted into the other form of useful mechanical energy and then converted into electricity. Wave power has a high potential to be captured and used for generating electricity in future as the technology develops further.   Wave energy has been used since 1890s. There is a lot of energy stored in waves. 94% energy of the ocean stored in the wave, and the other 6% is tidal energy.  Only small a part of the wave power is used for commercial electricity generation today.   The China is a developing country with a very large population which annually consume about 3073TWh electricity of which 496TWh is from renewable energy.  The wave power was less than 1GWh in 2007 (reference from International Energy Agency). The World Energy Council has measured the total useful power of the ocean wave energy to be more than 2TW in the world and corresponding to 6000TWh per year. There is about 70GW useful wave power resources in China, equivalent to an annual useful wave power resource of 200TWh.   The lowest capital cost for the wave power system is today around 0.1Euro/kWh. China will in the future focus on the development electricity generation by wave power. There will be hundreds of new wave power plant built in China during the next twenty years, and the total installed capacity will be larger than 1GW at 2030, which delivers 3TWh annually. This corresponds to less than 1 percent of the total use of electricity in China.   This thesis focuses on the functionality, efficiency and economic pay-off of existing ocean wave power systems, as well as how easy the ocean wave power can produce electricity. Firstly it discusses the physical concepts of wave power, and then focus on the existing wave power systems around the world. It is concluded from the Chinese sea characteristics and the designed conditions of different wave power systems, that the Pelamis and Oyster wave power converters are the best suitable systems for China.

Microfluidic chips have gained wide applications in various fields, including medicine, environmental sciences and forensic investigations. They are used for the separation of proteins, blood, bacterial cell suspensions, antibody solutions, and drugs. Microfluidic chips display significant advantages, which include faster analysis time, reduced amounts of samples and reagents volumes, flexibility in design and increased separation efficiency. Whole column imaging detection (WCID) exhibits significant advantages compared to other detection methods that are widely used for detecting analytes after the separation of these analytes using isoelectric focusing. With these other methods, there is a need to mobilize the focused sample bands past the detector after separation but with WCID, there is no need for mobilization step. The aim of this research is further development of WCID by characterizing microfluidic chips fabricated for the detection system, to enhance its detection so that high efficiency can be obtained. The chips were fabricated using soft lithography technology at the Microfluidic laboratory, University of Waterloo and they were used to perform isoelectric focusing of various proteins in our laboratory. The fabricated chips with straight channel design were used to carry out isoelectric focusing of some proteins and the results obtained were compared with the results obtained using commercial cartridges. The chips with tapered channel design were used to carry out isoelectric focusing of proteins in which thermally generated pH gradient principle was employed. The samples after separation were sprayed into a mass spectrometer using nano-electrospray interface to obtain their molecular masses. Compatible cartridges for nano-electrospray mass spectrometer were developed and these cartridges were used to carry out capillary isoelectric focusing of low molecular pI markers and proteins. These cartridges were also connected to the nano-electrospray mass spectrometer to obtain the mass to charge ratios of some proteins. The fabricated microfluidic chips with straight channel design were also used to investigate the interaction between drugs and protein.

Tropospheric ozone columns (TCOs) derived from differences between the Dutch-Finnish Aura Ozone Monitoring Instrument (OMI) measurements of the total atmospheric ozone column and the Aura Microwave Limb Sounder (MLS) measurements of stratospheric ozone columns are discussed. Because the measurements by these two instruments are not spatially coincident, interpolation techniques, with emphasis on mapping the stratospheric columns in space and time using the relationships between lower stratospheric ozone and potential vorticity (PV) and geopotential heights (Z), are evaluated at mid-latitudes. It is shown that this PV mapping procedure produces somewhat better agreement in comparisons with ozonesonde measurements, particularly in winter, than does simple linear interpolation of the MLS stratospheric columns or the use of typical coincidence criteria at mid-latitudes. The OMI/MLS derived tropospheric columns are calculated to be 4 Dobson units (DU) smaller than the sonde measured columns at mid-latitudes. Standard deviations between the derived tropospheric columns and those measured by ozonesondes are 9 DU (30%) annually but they are just 6 DU (15%) in summer. Uncertainties in the interpolated MLS stratospheric columns are likely to be the primary cause of these standard deviations. An important advantage of the PV mapping approach is that it works well when MLS data are missing (e.g., when an orbit of measurements is missing). In the comparisons against ozonesonde measurements, it provides up to twice as many comparisons compared to the other techniques. The OMI/MLS derived tropospheric ozone columns have been compared with corresponding columns based on the Tropospheric Emission Spectrometer (TES) measurements, and Regional chEmical trAnsport Model (REAM) simulations. The variability of tropospheric ozone columns has been examined for spring and summer 2005 over North America and the surrounding oceans. Comparisons of monthly mean distributions show good agreements between OMI/MLS tropospheric ozone columns, REAM columns, and TES columns. Two six-day periods in March have been selected to study the periodic TCO enhancements in two regions, around the Baja peninsula (Mexico) and over the West Coast of California. Thirteen-day back trajectories and daily maps of carbon monoxide (CO) and ozone from GEOS-CHEM and OMI/MLS have been used to investigate the influence of cross-Pacific transport. It is concluded that in the first period of the case study, the high ozone concentrations in mid and lower troposphere over the West Coast of California have been under the influence of cross-Pacific transport. Meteorological fields indicate that the high ozone concentrations in the upper troposphere over the West Coast of California and the high TCOs over the Baja peninsula are associated with stratospheric intrusions through a deep Rossby wave breaking event. The correlations between REAM TCOs and surface ozone from Environmental Protection Agency ground network measurements indicate that the TCO enhancement over the West Coast is associated with an increase of surface ozone. The correlations of REAM TCOs with geopotential height, wind fields, and tropopause height during the case study period suggest that TCO enhancement is best characterized in springtime by decreases of geopotential height on the 500 mb surface.

DNA gel electrophoresis is a critical analytical step in a wide spectrum of genomic analysis assays. Great efforts have been directed to the development of miniaturized microfluidic systems (“lab-on-a-chip” systems) to perform low-cost, high-throughput DNA gel electrophoresis. However, further progress toward dramatic improvements of separation performance over ultra-short distances requires a much more detailed understanding of the physics of DNA migration in the sieving gel matrix than is currently available in literature. The ultimate goal would be the ability to quantitatively determine the achievable level of separation performance by direct measurements of fundamental parameters (mobility, diffusion, and dispersion coefficients) associated with the gel matrix instead of the traditional trial-and-error process. We successfully established this predicting capability by measuring these fundamental parameters on a conventional slab gel DNA sequencer. However, it is difficult to carry out fast and extensive measurements of these parameters on a conventional gel electrophoresis system using single-point detection (2,000 hours on the slab gel DNA sequencer we used). To address this issue, we designed and built a new automated whole-gel scanning detection system for a systematic investigation of these governing parameters on a microfluidic gel electrophoresis device with integrated on-chip electrodes, heaters, and temperature sensors. With this system, we can observe the progress of DNA separation along the whole microchannel with high temporal and spatial accuracy in nearly real time. This is in contrast to both conventional slab gel imaging where the entire gel can be monitored, but only at one time frame after completion of the separation, and capillary electrophoresis systems that allows detection as a function of time, but only at a single detection location. With this system, a complete set of mobility, diffusion, and dispersion data can be collected within one hour instead of days or even months of work on a conventional sequencer under the same experimental conditions. The ability to acquire both spatial and temporal data simultaneously provides a more detailed picture of the separation process that can potentially be used to refine theoretical models and improve separation performance over ultra-short distances for the nextgeneration of electrophoresis technology.

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