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No description available.

No description available.

During an earthquake, unanchored equipment within a nuclear power plant facility can slide and interact with safety-critical systems and components. Previous studies on sliding have largely focused on the response due to unidirectional excitation, as computing the response of unanchored components in three dimensions can be complex and computationally expensive. As such, several prediction equations and a standardized approximate method as outlined in ASCE 4-16 have been developed to estimate the peak sliding displacement. This study investigates the effect of bidirectional horizontal interaction and the influence of vertical excitation on the sliding response of an unanchored object when the x, y, and z, components of earthquake excitation are applied simultaneously. The study also evaluates the approximate method detailed in ASCE 4-16. A suite of 40 floor acceleration histories obtained from response history analysis of a representative nuclear power plant facility are used as input for the sliding model. A wide range of friction coefficients is selected for analysis and the nonlinear sliding response of components is determined through the use of a Bouc-Wen type hysteretic model. Computed responses under uni-, bi- and tri-directional excitation reveal that the effect of bidirectional interaction and vertical excitation is greatest for sites with high shaking intensity. It is also concluded that the ASCE 4-16 approximate method is significantly overconservative in all cases. Additionally, the study expands the concept of multi-component excitation to intensity measures. Twelve intensity measures are selected and evaluated. It is found that most efficient intensity measures vary in efficiency depending on the coefficient of friction, and that the top intensity measures are not significantly affected by incorporating multiple components of excitation. / Thesis / Master of Applied Science (MASc) / Earthquakes can pose a huge risk to nuclear facilities. Unanchored objects within the facility may collide and interact with safety-critical equipment. Previous research on sliding behaviour lacks information on the response of an object subjected to earthquake excitation in both the horizontal plane and vertical direction simultaneously. Several prediction equations and an approximate method have been developed to estimate the sliding response as it becomes computationally expensive to solve. This research investigates the influence of simulatenous multi-component excitation on the sliding behaviour and evaluates the current standardized approximate method of estimating sliding displacement. Recommendations are given based on the friction coefficient between the object and the base. The research also explores which characteristics of earthquake ground motion (e.g. acceleration, velocity, energy) are most indicative of sliding behaviour.

A method using a Fourier series is demonstrated to optimize an LED array for local dimming applications in liquid crystal display backlighting. The same optimization method is also suitable for LED displays in which the Moiré effect must be suppressed during photography with a minimum loss of spatial resolution. Initially, the angular intensity profile of a Lambertian LED is modelled when backlighting a Lambertian rear projection screen and compared to experimental data. An array of optimized LEDs and the resulting screen intensity pattern is then derived such that an intensity distribution with an intensity deviation of less than 2% is achieved. The angular intensity profile of the LED is modified using adjustable Fourier coefficients optimized according to an algorithm. The algorithm is designed to achieve an illuminated screen area of maximum size for a bounded LED backlight array to appear uniform in intensity to an observer. This Fourier series approach provides an elegant method to optimize the intensity profile of LED backlight arrays without the use of ray tracing. A lens was designed in order to provide this optimized intensity profile as well as created and tested. / Thesis / Master of Science (MSc)

Yes / Memory performance is usually impaired when participants have to encode information while performing a concurrent task. Recent studies using recall tasks have found that emotional items are more resistant to such cognitive depletion effects than non-emotional items. However, when recognition tasks are used, the same effect is more elusive as recent recognition studies have obtained contradictory results. In two experiments, we provide evidence that negative emotional content can reliably reduce the effects of cognitive depletion on recognition memory only if stimuli with high levels of emotional intensity are used. In particular, we found that recognition performance for realistic pictures was impaired by a secondary 3- back working memory task during encoding if stimuli were emotionally neutral or had moderate levels of negative emotionality. In contrast, when negative pictures with high levels of emotional intensity were used, the detrimental effects of the secondary task were significantly attenuated. / UK Biotechnology and Biological Sciences Research Council (BBSRC, reference: BB/H001476/1, and BB/H001476/2)

Two studies analyzed the factor structure of the 8-item Multidimensional Ethics Scale (MES) (Reidenbach and Robin, 1988, 1990), a 30-item MES (the 30 items used to develop the 8-item measure), and a Perceived Moral Intensity Scale. Factor analyses supported a 3-factor structure for the 8-item MES, marginally supported a 5-factor structure (but more strongly suggested a 1-factor structure) for the 30-item MES, and supported a 3-factor structure for the Perceived Moral Intensity Scale. These scales were then used in a third study that examined the effect of manipulated and perceived moral intensity (Jones, 1991) on participants' ethical judgment of actions taken in 18 scenarios of an arguably ethical nature. A within-subject design found that manipulated moral intensity had a significant effect on ethical judgment, but perceived moral intensity did not. When ethical judgment (as measured by the three factors of the 8-item MES) was regressed on age, gender, major, perceived moral intensity factors, and interactions between age, gender, major and perceived moral intensity factors, the variance accounted for (R2) was significant for each of the three ethical judgment factors in both high and low intensity conditions using a between-subjects design, but was only significant for one of the ethical judgment factors (Moral Equity), and this only for low intensity scenarios, using a within-subject design. One explanation for the difference in effect appears to be that the means for the three perceived moral intensity factors were significantly different for the low versus high intensity condition using the between-subjects design, but the means of two of the three factors were not significantly different using the within-subject design. Three explanations for this were suggested: perceived moral intensity may not have reached a necessary threshold due to explicit referents for comparison; cognitive demand may have been greater when two versions of a single scenario were being evaluated; and, the online administration of the study may have introduced greater error variance than the in-person paper-pencil administration. Ethical judgment was found to be a more robust predictor of intention than perceived moral intensity using a within-subject design. Suggestions were made for future research. / Ph. D.

A three-stage Experimental Spatial Power Flow (ESPF) method which computes an experimentally derived, spatially continuous representation of the structural power in l-D and 2-D structures is presented. The three stages of the ESPF method consist of first using a scanning laser Doppler vibrometer (SLDV) to acquire spatially dense measurements of the structure's dynamic response. Second, the continuous 3-D complex-valued velocity field is solved from the laser data. Third, a spatially continuous model of the power is computed from the velocity-field model obtained in stage 2. The results of the ESPF method were validated by using both simulated and experimental laser data. In the simulated laser data cases, the power injected into a simply supported plate computed analytically, compared to within 1.33% of the power injected as computed by the ESPF method. In the experimental validation, three methods were used to compute the power injected and extracted from a simply supported plate forced with two shakers. The three methods consisted of the ESPF method and two methods of computing the injected power using impedance head type measurements. The injected power results were compared at four different frequencies. These frequencies were 79.0 Hz, 311.0 Hz, 909.0 Hz, and 1100.0 Hz. In all cases, the injected and extracted power results of the three methods compared to within 20% and to within 12% for all cases except the 909.0 Hz case. These results are currently better than other experimental techniques. Advantages of this method are 1) a spatially continuous representation of the power is computed 2) the affects of the actual boundary conditions and near-field effects of the structure are inherently measured by the SLDV 3) the SLDV does not affect the response of the structure by mass loading and is fully portable for in-field testing 4) the method allows for convergence of the power-flow vector field in addition to convergence of the velocity field and 5) the ESPF method is extendable to account for power due to in-plane motion and to account for shells of arbitrary geometry. / Ph. D.

Eighteen untrained males [age: 23 +/- 0.6 yr (SEM)] were randomized into high intensity (HIT: above lactate threshold, LT), moderate intensity (LIT: below the LT) or no training (NT) groups. Subjects trained on a cycle ergometer 4 days.wk-1 for 6 wk with the power output held constant. Maximal cycle ergometry was performed before and after the training period to determine changes in power output and oxygen consumption (VO2) at the LT and peak exertion. Before training and after 1, 2, 4, and 6 wk, subjects performed high constant-load (HCL) cycling bouts to quantify training adaptations in the SC. Training was designed to keep total work equivalent between the HIT and LIT groups. Increases in power output and VO2 at LT and peak exercise after 6 wk were noted in the HIT and LIT groups in comparison to NT group (p<0.05). No differences were noted between HIT and LIT. Two-way repeated measures ANOVA revealed a significant trial*group interaction for adaptation in the SC (p<0.001). After 1wk of training, a significant reduction in the SC was noted for HIT [mean+/-SEM]: (pre-training (PT): 703 +/- 61 ml.min-1; 1 wk: 396 +/- 60 ml.min-1) (- 44% from PT). Further adaptation for the HIT was also noted at 4 wk: 202 +/- 45 ml.min-1 (-71% from PT). For LIT, a significant reduction was noted at 2 wk (PT: 588+/-76 ml.min-1; 2 wk: 374 +/- 50ml.min-1) (-36% from PT). Further adaptation for LIT group was noted at 6 wk (252 +/- 38 ml.min-1) (- 57% from PT). Adaptation in SC was not noted at any interval for NT. Temporal changes in blood lactate (r = 0.40) and ventilation (r = 0.72) were significantly correlated with the changes for SC over the 6 wk training period (p<0.05). In conclusion, it was demonstrated that training at supra-LT and sub-LT intensities produces similar improvement in VO2 and power output at peak exercise and in the LT, when total work output is controlled. However, training at supra-LT intensity promotes larger and faster adaptations in the SC than training at the sub-LT levels. / Ph. D.