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Sustainable algae biofuel production is rising in demand, and the need to establish an efficient and proper algae harvesting method is extremely essential. Membrane filtration technology seems to be the most promising as a solid-liquid separation process. However, fouling seems to be the major problem for membranes. There is limited research on how to solve the problem of fouling, and cake buildup inside the membranes. A novel membrane design is required to solve the problem of fouling and cake buildup inside the membranes. The objective of this research is to construct a novel two way membrane design for algae biomass harvesting and water recycling. The methods used include culturing algae species, filtering them through the membrane module, and sample analysis for determining the water quality. The results show that the present filtration model had no fouling, or cake buildup as opposed to the previous filtration model. The present model permeate has a very low optical density of 0.007 absorbance at 750 nanometers. This result shows that permeate is completely devoid of algae.

published_or_final_version / Botany / Master / Master of Philosophy

Power consumption of CMOS digital logic designs has increased rapidly for the last several years. It has become an important issue, not only in battery-powered applications, but also in high-performance digital designs because of packaging and cooling requirements. At multi-GHz clock rates in use today, charging and discharging CMOS gates and wires, especially in clocks with their relatively large capacitances, leads to significant power consumption. Recovering and recycling the stored charge or energy about to be lost when these nodes are discharged to ground is a potentially good strategy that must be explored for use in future energy-efficient design methodologies. This dissertation investigates a number of novel clock energy recycling techniques to improve the overall power dissipation of high-performance logic circuits. If efficient recycling energy of the clock network can be demonstrated, it might be used in many high-performance chip designs, to lower power and save energy. A number of chip prototypes were designed and constructed to demonstrate that this energy can be successfully recycled or recovered in different ways: • Recycling clock network energy by supplying a secondary DC-DC power converter: the output of this power converter can be used to supply another region of the chip, thereby avoiding the need to draw additional energy from the primary supply. One test chip demonstrates energy in the final clock load can be recycled, while another demonstrates that clock distribution energy can be recycled. • Recovering clock network energy and returning it back to the power grid: each clock cycle, a portion of the energy just drawn from the supply is transferred back at the end of the cycle, effectively reducing the power consumption of the clock network. The recycling methods described in this thesis are able to preserve the more ideal square clock shape which has been a limitation of previous work in this area. Overall, the results provided in this thesis demonstrate that energy recycling is very promising and must be pursued in a number of other areas of the chip in order to obtain an energy-efficient design.

The City of Saskatoon is responsible for maintaining approximately 1,100 km of roads including locals, collectors, arterials, and freeways. With the aged state of the road infrastructure, increasing budget constraints limit the City’s ability to maintain existing road infrastructure to an acceptable level of service and to construct new road infrastructure. The infrastructure demands related to urban growth within the City of Saskatoon have caused a shrinking aggregate supply and increasing aggregate demand. In turn, growing demand and dwindling resources for aggregate are resulting in rapid increases to road construction costs. Aggregate sources are a non-renewable resource in Saskatchewan. Therefore, road designers do not have an endless supply of quality aggregates. With limitations of the road building industry and the foreseeable economic growth projected for the City of Saskatoon, it is reasonable to expect that the unit costs of providing conventional pavement structures will continue to increase in Saskatoon. Presently, the primary conventional road building materials include well graded granular base material, subbase, crushed rock and a wearing surface of either conventional hot mix asphalt concrete (HMAC) or Portland cement concrete (PCC). To ensure long term pavement performance, quality aggregate sources are needed in all road design structural layers. Recent years have seen an increased need for substructure drainage systems, therefore increasing the need for high quality crushed rock. City of Saskatoon, like other urban centers, generates significant stock piles of concrete rubble annually. The primary objective of this research was to compare PCC material properties to those of conventional granular materials under realistic field state conditions. The second objective of this research was to validate the economic feasibility of using recycled PCC material within City of Saskatoon road structure through test section design and field test sections’ structural performance. Conventional and mechanistic material characterization was completed for recycled PCC well graded base course and recycled PCC drainage rock derived from PCC rubble, as well as conventional City granular base and drainage rock aggregates from typical City of Saskatoon stockpiles. Conventional testing completed on the samples included physical properties as required by COS aggregate specifications. Micro-Deval testing was also completed to compare the mechanical breakdown of the aggregates tested. Based on the results of the conventional tests performed, the recycled PCC well graded base and the recycled PCC drainage rock were found to meet COS base and drainage rock specifications, respectively. The recycled PCC well graded base material, recycled PCC drainage rock, COS granular base, and recycled PCC well graded base stabilized with different percentages of cement and slow setting type one (SS-1) asphalt emulsion were the research materials mechanistically tested. These materials were mechanistically tested using triaxial frequency sweep characterization to derive the mechanistic material constitutive relations across all the materials. Five repeat samples were gyratory compacted and tested at room temperature using the rapid triaxial testing. To characterize climatic durability, all the samples were moist cured for 28 days, characterized using the rapid triaxial test; then vacuum saturated and then characterized again using the rapid triaxial test. The mechanistic properties measured for the PCC material showed better climatic durability compared to those measured for the virgin aggregates, particularly after climatic durability testing. Prior to vacuum saturation, the conventional COS granular base had a peak dynamic modulus of 457 MPa. Under the same testing conditions, recycled PCC well graded base unstabilized had a stiffness of 1081 MPa; the stabilized PCC samples with two percent cement had a dynamic modulus of 1542 MPa. The radial micro strain and Poisson’s ratio were reduced for well graded PCC materials both unstabilized and stabilized compared to the conventional COS granular base. The conventional granular base had a peak radial micro strain of 194 compared to the untreated recycled PCC well graded base peak radial micro strain of 54 at the same testing parameters of low stress state at a testing frequency of 10 Hz prior to vacuum saturation. The conventional COS granular base samples failed under high deviatoric stress state at a 0.5 Hz testing frequency prior to vacuum saturation, whereas the PCC materials survived all testing frequencies and stress states. However, after vacuum saturation, the unstabilized recycled PCC well graded base samples failed under high stress state under a 10 Hz testing frequency. To validate field structural performance, two road structures within the City of Saskatoon were used as test sections in which recycled PCC drainage rock was used as a structural drainage layer. The first test section was constructed in the east bound lane of Marquis Drive, and the second was completed at the University of Saskatchewan. Prior to construction of both the Marquis Drive and North Road test sections, both sections were tested for peak surface deflections using the heavy weight deflectometer. Segment 1 of Marquis Drive had an average pre construction surface deflection of 1.85 mm under a primary weight limit. Section 1 of North Road had an average pre construction surface deflection of 1.17 mm under primary weight limit. After construction was complete on both test sections using recycled materials including a PCC drainage layer, HWD testing showed post construction peak deflections were significantly lower than the deflections measured pre construction. Recycled PCC well graded base material performed well in mechanistic laboratory analysis. However, the material was not field tested in this research. Mechanistic laboratory and field analysis indicated that recycled PCC drainage rock aggregates met structural performance requirements. The capital cost analysis showed that using recycled PCC drainage rock can reduce the overall cost of road rehabilitation projects when compared to using conventional virgin aggregates, particularly crushed drainage rock. The Marquis Drive section had a cost savings of $89,000, and the University of Saskatchewan section had a cost savings of $75,800 when recycled materials were used in lieu of virgin aggregates to rehabilitate the pavement structure. In addition, no PCC was disposed of in the landfill, saving the City of Saskatoon tipping fees and extending the life of the landfill. This research showed that the crushed PCC rubble is both technically and economically feasible to use as high quality aggregates in City of Saskatoon streets. Based on the findings of this research, the City of Saskatoon should pursue the use of recycled PCC rubble aggregates in urban road construction.

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The central focus for this creative project was to explore the possibilities of found object and recycled art with emphasis on function and design. After researching the art and the artists who made/make it, a collection of functional art was created. The project resulted in a body of work that consisted of thirteen bags and purses that were made from gift cards and gameboards. The design of 1970's and 1980's art was used as inspiration. Traditional metalsmithing techniques were required for the completion of each work. Copper wire was used as both a structural and ornamental element. The awareness of recycled art will be heightened. Found object and recycled art is significant, purposeful, and important in both the history and future of art. / Department of Art