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There are two ways that attentional resources can be aligned in visual space. They can be "pulled" automatically by stimulus cues, or "pushed" in a more strategic manner by the observer in response to information cues. The present study was designed to determine if the ability to align attention in these two ways changes throughout the course of the lifespan. Subjects (6, 8, 10, 23, and 73 years) were tested in two conditions. In the first, subjects were presented with a stimulus cue (a dot that appears briefly at a target location) prior to the presentation of a target. Attention was automatically aligned to a possible target location in response to the stimulus cue. In the second, an arrow was presented prior to the target, allowing the subject to align attention strategically in response to the cue. Cues were either valid or invalid predictors of target location, cue-target SOA was varied so the time course for the effective use of both types of cues was measured and compared. Eye movements were monitored to control for confounding developmental differences in vision. In a second experiment, lifespan changes in the interaction between the two forms of orienting were assessed by presenting subjects with both cues on each trial. The location information provided by each cue could be either compatible or incompatible with each other. The results of both experiments suggest that the ability to align attention automatically changes very little from early childhood through old age. Strategic attention alignment becomes more efficient in early adulthood. Children have difficulty sustaining attention at locations specified by information cues and seniors have difficulty using the information rapidly. Both children and seniors are less able to use information cues when stimulus cues are also available where as young adults can use both. These findings suggest that separate mechanisms are required to implement attention alignments to automatic and strategic cues.

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Theoretical equations were developed for calculating the apparent elastic modulus and the strength of corn cob under quasi-static radial compression and simple bending. An empirical equation was derived for calculating its modulus of toughness. / Experimental justification was provided for the application of the Hertz linear elastic contact theory in determining cob mechanical properties in radial compression, since the cob is a composite of three inelastic materials. / In simple bending, the basic flexure formula was modified to account for the composite and tapered structure of the cob. / The relative contributions of the macro-structural components of the corn cob to its mechanical properties were determined. / Cob mechanical properties were found to be significantly affected by corn variety, harvest date and moisture content, but not by loading rate. Further experimental investigations showed that the cob mechanical properties were much dependent on fertilizer type and application rate but less dependent on soil type and condition.

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The accelerated durability test is an important part for design and manufacturing ground vehicles. It consists of test designed to quantify the life characteristics of a ground vehicle component under normal use conditions by testing the unit at higher stress levels to accelerate the occurrence of failures. The challenge of conducting accelerated durability tests is to create the driven profile. In general, the mission profiles of the accelerated durability test can be generated via the acceleration data of the events experienced by the vehicle during the field test. Accurately separating the time series signal that correlate the load events becomes essential to efficiently generate the mission profiles for the accelerated test analysis. The representative Power Spectrum Density (PSD) profile can be generated based on the mission profiles. Then, the driven profile for the sub-scaled accelerated durability test, i.e., the acceleration data can be generated based on the PSD data.

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