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

General Practice and Pandemic Influenza: A Framework for Planning and Comparison of Plans in Five Countries

BACKGROUND: Although primary health care, and in particular, general practice will be at the frontline in the response to pandemic influenza, there are no frameworks to guide systematic planning for this task or to appraise available plans for their relevance to general practice. We aimed to develop a framework that will facilitate planning for general practice, and used it to appraise pandemic plans from Australia, England, USA, New Zealand and Canada. METHODOLOGY/PRINCIPAL FINDINGS: We adapted the Haddon matrix to develop the framework, populating its cells through a multi-method study that incorporated the peer-reviewed and grey literature, interviews with general practitioners, practice nurses and senior decision-makers, and desktop simulation exercises. We used the framework to analyse 89 publicly-available jurisdictional plans at similar managerial levels in the five countries. The framework identifies four functional domains: clinical care for influenza and other needs, public health responsibilities, the internal environment and the macro-environment of general practice. No plan addressed all four domains. Most plans either ignored or were sketchy about non-influenza clinical needs, and about the contribution of general practice to public health beyond surveillance. Collaborations between general practices were addressed in few plans, and inter-relationships with the broader health system, even less frequently. CONCLUSIONS: This is the first study to provide a framework to guide general practice planning for pandemic influenza. The framework helped identify critical shortcomings in available plans. Engaging general practice effectively in planning is challenging, particularly where governance structures for primary health care are weak. We identify implications for practice and for research

Differential connectivity and response dynamics of excitatory and inhibitory neurons in visual cortex

Neuronal responses during sensory processing are influenced by both the organization of intracortical connections and the statistical features of sensory stimuli. How these intrinsic and extrinsic factors govern the activity of excitatory and inhibitory populations is unclear. Using two-photon calcium imaging in vivo and intracellular recordings in vitro, we investigated the dependencies between synaptic connectivity, feature selectivity and network activity in pyramidal cells and fast-spiking parvalbumin-expressing (PV) interneurons in mouse visual cortex. In pyramidal cell populations, patterns of neuronal correlations were largely stimulus-dependent, indicating that their responses were not strongly dominated by functionally biased recurrent connectivity. By contrast, visual stimulation only weakly modified co-activation patterns of fast-spiking PV cells, consistent with the observation that these broadly tuned interneurons received very dense and strong synaptic input from nearby pyramidal cells with diverse feature selectivities. Therefore, feedforward and recurrent network influences determine the activity of excitatory and inhibitory ensembles in fundamentally different ways