Snowfall Simulator Quick-Release Retrofit

In the early 1990s, UCAR fabricated a snowfall simulator that they have used to test deicing fluids for aircraft, among other applications. Ice cores are actuated by a stepper motor and travel along a linear guide rail feeding it into an auger bit. This bit shaves the ice core, creating conditions that simulate snowfall. Currently, the simulator is in satisfactory operating condition, however upgrades have been proposed to make the simulator more user friendly. When one ice core has been exhausted, the motor controlling the carriage must be actuated in reverse to move the mount along a lead screw back to reloading position, which can take upwards of three minutes. The purpose of this project is to retrofit the simulator with a quick release system that allows for the user to manually unlock the carriage and quickly pull it back into the reloading position, decreasing turn around time in the testing process. The final design is a symmetric 2-clamp system that is installed directly onto the ice core mount. The two clamps engage the lead screw from the left and the right. To reload the ice cores, the user must simply lift the Destaco clamps on each side and pull the entire carriage back to the original position at the front of the simulator

Water Fun at Exploration Station

This report documents the design and fabrication processes involved for the creation of an interactive science exhibit for the Grover Beach Exploration Station. This is a student-led senior project advised by Sarah Harding, professor of mechanical engineering, as a part of California Polytechnic State University in San Luis Obispo’s mechanical engineering program. The final product is a fully functioning, durable system that is capable of pumping and recycling water throughout use when users are in its vicinity. The exhibit is to be considered in 4 main subsystems: basin, plumbing, frame, and sleep mode system. A fiberglass basin that holds all the water in the exhibit sits recessed inside a welded steel frame. Water is pumped through the bottom of the basin from within an enclosed storage area inside the frame, and is recycled back into the water reservoir by placement of two weir valves. A submersible pump powers the exhibit, and is controlled by passive infrared sensors that activate when human presence is sensed within 15ft. While the manufacturing process did reach completion, testing and verification did not. However, proposed testing plans are still included in the appendices of the report for informational purposes. Divided into distinct sections, this report will enlighten the reader on each part of the design process. First, background research and preliminary design explains the methodology of developing the vision of the final design. Next, different design analysis techniques are given for each respective subsystem of the proposed exhibit. An in-depth description for manufacturing and testing of the completed exhibit is given for each subsystem. Finally, recommendations are given for future improvements to the exhibit, and what kinds of different decisions would be made in the design process if given a second iteration

The Moderating Effect of Family-Ownership on Firm Performance: An Examination of Entrepreneurial Orientation and Social Capital

Within the small business literature, a number of recent studies have examined the importance of entrepreneurial orientation (EO) and the development of social capital (SC) as each contributes to a firm's performance. While it is generally accepted in previous studies that each of these constructs positively affects firm performance, relatively less attention has been paid to potential moderating factors that can affect these relationships. The purpose of our research is to address one such moderator, family ownership. Using structural equation modeling (SEM) to test the moderating effect of family ownership on the relationships among entrepreneurial orientation, social capital, and firm performance, our results show that the effects of EO and SC vary depending upon whether the firm is family-owned or non-family owned. Implications of these findings and future research directions are provided

Membrane-Bound Steel Factor Maintains a High Local Concentration for Mouse Primordial Germ Cell Motility, and Defines the Region of Their Migration

Steel factor, the protein product of the Steel locus in the mouse, is a multifunctional signal for the primordial germ cell population. We have shown previously that its expression accompanies the germ cells during migration to the gonads, forming a “travelling niche” that controls their survival, motility, and proliferation. Here we show that these functions are distributed between the alternatively spliced membrane-bound and soluble forms of Steel factor. The germ cells normally migrate as individuals from E7.5 to E11.5, when they aggregate together in the embryonic gonads. Movie analysis of Steel-dickie mutant embryos, which make only the soluble form, at E7.5, showed that the germ cells fail to migrate normally, and undergo “premature aggregation” in the base of the allantois. Survival and directionality of movement is not affected. Addition of excess soluble Steel factor to Steel-dickie embryos rescued germ cell motility, and addition of Steel factor to germ cells in vitro showed that a fourfold higher dose was required to increase motility, compared to survival. These data show that soluble Steel factor is sufficient for germ cell survival, and suggest that the membrane-bound form provides a higher local concentration of Steel factor that controls the balance between germ cell motility and aggregation. This hypothesis was tested by addition of excess soluble Steel factor to slice cultures of E11.5 embryos, when migration usually ceases, and the germ cells aggregate. This reversed the aggregation process, and caused increased motility of the germ cells. We conclude that the two forms of Steel factor control different aspects of germ cell behavior, and that membrane-bound Steel factor controls germ cell motility within a “motility niche” that moves through the embryo with the germ cells. Escape from this niche causes cessation of motility and death by apoptosis of the ectopic germ cells

The study of the epitaxial parameters on reliability of silicon planar devices technical summary report, 25 jun. 1964 - 25 jun. 1965

Effect of varying epitaxial deposition parameters on reliability of silicon planar solid state device