Science One Research Projects 2011-2012Collection of undergraduate research projects for UBC Science Onehttp://hdl.handle.net/2429/410822015-04-26T05:50:52Z2015-04-26T05:50:52ZBounds on Rubik's cube and mirror cube configurations (Issued:2012-06-30)Hsu, GraceLiu, Sissihttp://hdl.handle.net/2429/426502012-07-17T18:05:54Z2012-06-30T00:00:00ZGiven a 3x3x3 mirror cube, we find the number of valid and distinct projections up to and including three 90° turns. Next, we calculate the number of valid permutations of the traditional 3x3x3 Rubik's cube such that it has at least one, two, three, four, five or six faces with the same colour. We then return to the mirror cube and find improved upper bounds for the number of distinct projections.
2012-06-30T00:00:00ZMeasurement and prediction of efficiency loss in LEDs (Issued:2012)Strang, KielGreenstreet, Laurahttp://hdl.handle.net/2429/424612012-06-21T15:01:02Z2012-01-01T00:00:00ZAn order of magnitude improvement in power efficiency of light emitting diodes (LEDs) over incandescents makes them ideally
suited for a variety of applications. GaInN LEDs, used to produce white light, exhibit a loss of efficiency with increased power. By
measuring the efficiency of GaInN and GaAs LEDs we found losses beginning within their rated range. Linear regression allowed
us to develop polynomial and power law models for efficiency loss. Models were evaluated using measurements at high power,
with the power law model providing the best fit. Our results suggest further research should be conducted on temperature-related
efficiency loss and its underlying causes.
2012-01-01T00:00:00ZInvestigation of surfactant surface tension and its correlation with temperature and concentration (Issued:2012)Cheng, Li Yaw (Michael)Wei, Su Min (Lisa)http://hdl.handle.net/2429/424602012-06-21T14:13:45Z2012-01-01T00:00:00ZSurface tension is a property that defines the energy per unit area of a liquid-gas interface. The purpose of this study
is to investigate the surface properties and the process of aggregation of surfactant micelles in detergents. By using a
drop-weight method, the surface tension of detergent solutions was determined under standard pressure condition 1
bar. A 100% concentrated detergent solution was subject to heating. Data analysis showed that surface tension decreased
linearly with increasing temperature, as represented by the equation ƴ = – 0.1766 mN/(m⋅K)(x) + 94.654
mN/m, where x is temperature. When subjected to variations in concentration, surface tension of the detergent decreased
until reaching the critical micelle concentration, as modelled by the segmented linear regression ƴ = – 0.565
mN/(m⋅%)(x) + 61.7 mN/m when x < 50%, and ƴ = 33.45 mN/m when x ≥ 50%, where x is concentration.
2012-01-01T00:00:00ZDetermination of the ultimate tensile strength of common household materials by a loading method (Issued:2012)Carter, IanMoffatt, Andrewhttp://hdl.handle.net/2429/424592012-06-21T14:56:09Z2012-01-01T00:00:00ZAn experiment was carried out to determine the ultimate tensile strength of four different household materials: extruded polystyrene, porcelain tiles, printer paper, and wood. Tensile strength was evaluated using the method of loading the materials until they catastrophically failed, and then calculating the force applied when the failure occurred and measuring the cross-sectional area of the failure zone. Paper was determined to have the highest ultimate tensile strength, followed in decreasing order by wood, porcelain tiles, and extruded polystyrene.
2012-01-01T00:00:00Z