The sludge blinding coefficient, β, was evaluated in this experimental study, to determine if β could be used as a useful characterization parameter for sludge filterability. Fresh activated sludge, activated sludge aged at room temperature, primary sludge, alum sludge, and a calcium carbonate slurry were filtered using a Buchner funnel apparatus and varying size filter media at various pressure differentials. Particle size measurements were also performed on the above mentioned sludges using an automated particle size analyzer to examine the impact of particle size and size distribution on β. Effects of conditioning, elutriation, supernatant removal, and replacement on β were also studied. In general, β correlated well with the average specific resistance, indicating that it could be useful in predicting a sludge filtration pattern. β was found to increase as the mean particle size of a sludge decreased, or the particle size distribution of a sludge widened. Conditioning, elutriation, supernatant removal, and replacement were found to reduce β by improving the mean particle size of a sludge and narrowing a sludge particle size distribution. In addition, β was found to increase by the applied pressure differential and filter media pore sizes for a few sludges. / Master of Science

Optimization techniques are used to investigate changes in structural design which increase the energy absorbing capabilities of a marine vessel in a collision. The structural model of the vessel includes the stiffened shell, web frame supports, and rigid bulkheads. The failure criterion used is hull rupture, appropriate for tanker design. The collision scenario is a right angle strike by a rigid vertical bow midway between two rigid bulkheads. The stiffened shell is modelled as a series of longitudinal beams in plastic bending and plastic membrane tension. Optimization parameters included both the number and dimensions of the transverse web frames and longitudinal beams. The technique was applied to the redesign of a large oil tanker. Minimizing the weight with a constraint on the energy was superior to maximizing the energy with a weight constraint in both computation time and performance. Optimization increased the volume of the shell beams while decreasing their moment-of-inertia. In addition the volume and strength of the frame were decreased precipitating early development of membrane tension in the shell and spreading of damage throughout the compartment. An reduced the number of web frames from optimum design six to two and increased the energy absorbed before rupture by 130%. Lesser collisions energies were found for more conservative designs which included a set number of web frames and restrictions of other design parameters. The use of high strength steel was also investigated. / M.S.

The possibility that visual thresholds fluctuate in a circadian rhythmic (twenty-four hour) pattern was examined. Subjects were tested at 0400h, 1000h, 1600h and 2200h in a 30 minute dark adaptation procedure using a von Békésy tracking method. Two experiments were performed; the first tested cone functions with a red 1 degree monochromatic test stimulus located ten degrees nasally. There were no sex differences for the ten male and female subjects used in this study. However, there were time of day differences with higher thresholds at 1000h than at any other time. The second experiment examined both rod and cone thresholds with a heterochromatic test stimulus. Sex differences were found 'for the 10 male and 10 female subjects. The rods for males were found to exhibit significantly higher thresholds at 1000h than any other time. There were no significant differences for females. The null results for females may be due to an influence of the menstrual cycle on vision. The rod differences for males is thought to occur because of rod outer segment shedding which also has a circadian rhythm. A circadian rhythm questionnaire was administered to the subjects and it was found that morningness and vigorousness related to visual thresholds. / Master of Science

A higher-order shear deformation theory is used to analyze laminated anisotropic composite plates for deflections, stresses, natural frequencies, and buckling loads. The theory accounts for parabolic distribution of the transverse shear stresses, satisfies the stress-free boundary conditions on the top and bottom planes of the plate, and, as a result, no shear correction coefficients are required. Even though the displacements vary cubically through the thickness, the theory has the same number of dependent unknowns as that of the first-order shear deformation theory of Whitney and Pagano. Exact solutions for cross-ply and anti-symmetric angle-ply laminated plates with all edges simply-supported are presented. A finite element model is also developed to solve the partial differential equations of the theory. The finite element model is validated by comparing the finite element results with the exact solutions. When compared to the classical plate theory and the first-order shear deformation theory, the present theory, in general, predicts deflections, stresses, natural frequencies, and buckling loads closer to those predicted by the three dimensional elasticity theory. / Master of Science

The main purpose of this research is to determine if polymer films can prevent fretting between two metals, and if they can, what the protection mechanisms are. This research is a part of fretting corrosion studies currently funded by the Army Research Office. Four thermoplastic polymers were tested for their effectiveness. Two other independent variables were also tested: plate hardness and plate roughness. A ball-on-plate device was built to approximate point sliding at the fretting corrosion interface. The tribometer has two experimental positions that are electrically insulated from the rest of the apparatus so that an electrical circuit could be used to monitor metal-to-metal contact. All experiments were run with 52100 steel balls, 1040 steel plates, a normal load of 45 N (10 lbf), an amplitude of .33 mm (.013 in.) and a frequency of 20 Hz. PVC films were found to prevent fretting and metallic contact for 40 minutes. An electrochemical fretting corrosion mechanism has been suggested to explain this behavior. PTFE, LDPE, and PSF films could all produce fretting corrosion while preventing metal-to-metal contact for 40 minutes. Plate hardness and plate roughness had no statistical significance on the measured minimum fretting friction force. / M.S.

Basic components of nineteenth century American nationalism influenced the creation of a national library in the United States. Manifest destiny, mission, nativism, and cultural nationalism provided the impetus to build an institution that preserved, symbolized, and spread national thought and ideals. Five major congressional acts made the Library of Congress the national library. The expansion of the Library's rooms in the Capitol (1865), the transfer of the Smithsonian Institution library (1866), purchase of the Peter Force collection of Americana (1867), the copyright law of 1870, and approval of a new library building (1886), made the Library the center of literary deposit, and the cultural, intellectual representative of the United States. / Master of Arts

The effect of date and method of lifting on ethylene production by 1-0 loblolly pine (Pinus taeda L.) seedlings during cold storage, the dose-response relationship between ethylene and loblolly pine seedlings during cold storage, and the effect of water stress on ethylene and aminocyclopropane-1-carboxylic acid (ACC) production in two half-sib loblolly families were investigated. Seedlings stored in Kraft-Polvethvlene (K-P) bags showed a general trend of increasing ethylene concentrations from November through February, with an abrupt drop in March. Production rates may be related to the level of dormancy of the seedlings, with the peak in production corresponding to fulfillment of the chilling requirement. Ethylene concentrations within the K-P bags generally declined over the twelve weeks in cold storage. Roots produced significantly higher levels of ethylene while stored in the K-P bags; however, when incubated under light, the needles produced higher concentrations. Roots of machine-lifted seedlings produced significantly higher levels of ethylene than roots of hand-lifted seedlings. However, rates tended to moderate during storage and differences in production between HL and ML whole seedlings were not significant, which suggests that mechanical lifting is not a source of increased ethylene production. A dose-response study indicated that ethylene fumigation during cold storage tended to slightly enhance growth of outplanted seedlings. The effects of water stress on a Virginia Coastal Plain (CP) and an East Texas Drought Hardy (DH) loblolly family were also investigated. Ethylene production during severe stress (-2.8 MPa) appeared to be related to drought hardiness, with the CP seedlings producing much higher levels. Roots of both families produced greater levels of ethylene than the needles and may be due to an enhanced ability to convert 1-Aminocyclopropane-1-carboxylic acid (ACC) to ethylene. / Master of Science

Insignificant diurnal variations make the reliance on thermal inertia to ameliorate the thermal discomfort in the hot humid region impossible. Natural ventilation, therefore, is not only important, but the velocity of air that gets into the living area is crucial. Various ways of creating negative pressure (a process of increasing the interior air speed) are examined. The performance of roof types with different horizontal openings in enhancing interior air movement was investigated in an open throat wind tunnel. The results indicate a significant difference in the interior air velocity with roof type A opening type 1 (see fig. 27 and fig. 28). The thesis explores other ways of creating climate adapted architecture in providing acceptable comfort level in the hot humid climate. Warm humid climates are defined, and data for one example (Lagos, Nigeria) are analysed. Comfort zones are established relative to the region being investigated and the methods of limiting interior heat gain are described. The effects of orientation, cross ventilation and material choice are discussed. / Master of Architecture

The Large Format Camera is a high resolution wide-angle mapping camera. It will be carried into orbit as a payload in the Shuttle Orbiter vehicle's cargo bay. A mapping camera must be calibrated to determine precise values for its elements of interior orientation. The Large Format Camera was calibrated by the stellar method of camera calibration. Descriptions of the procedure used by the National Ocean Service to calibrate the Large Format Camera are included. / Master of Engineering

Québec Université Laval, Bibliothèque 2013