1. CLOSE-UP
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The equipment described herein contains the elements required to obtain ultrasound images aboard the KC-135 in such as way as to reduce anticipated error and obtain the necessary data to draw a relevant conclusion from our hypothesis. The layout of our experiment may be broken down into three necessary components: image acquisition, data acquisition, and subject positioning table.

The image acquisition portion of our experiment is relatively straightforward and uses manufactured components to obtain and record real-time ultrasound images. The SonoSite 180 Ultrasound System will be used for image acquisition. The images will be transferred to the monitor via the composite video output. The images are routed from the VCR to the video monitor mounted on the front of the video rack. The purpose of the monitor is to provide adequate viewing of real-time images while in flight so that the position of the transducer may be adjusted to obtain appropriate images in the desired views. BNC cables and the appropriate adapters will be used to transfer video data between components. The Horita SCT-50 Serial Control Titler allows us to post text in a small corner of the monitor. Data from the accelerometer, nasal flow meter, and time/date stamp generated by the unit will be posted to the screen. This allows us to properly synchronize the data with the images. Displaying this data to the monitor also allows us to view feedback from our system to ensure that the system is operating correctly. The acquisition method and a description of this data are provided in more detail in the data acquisition system.

The purpose of the data acquisition system is to correlate our images with the present gravitational environment and the state of respiration of the subject. The accelerometer is constructed using three Analog Devices ADLX105 chips to provide data in the X-Y-Z directions. The analog signal is subsequently fed to an analog-to-digital converter and routed to the serial port of the laptop computer. A Labview program has been written to format the data to text to be displayed on the video monitor. Text is transferred via the RS-232 serial port to the SCT-50 to display accelerometer data on the monitor. The SCT-50 has an internal clock calendar that generates time data to a tenth of a millisecond resolution and allows us to post time data to the screen.

The Subject Positioning Table will be constructed of a ¾" sheet of plywood covered with foam padding. The plywood base plate will measure 30" in width by 70" in length. Four bolts and washers will be used to secure the base plate to the aircraft floor grid. The washers will measure at least six times the diameter of the bolts used. Hard foam padding, one- inch thick, will be secured to the plywood using screws. In order to secure the subject to the table 3 inch nylon strapping will be located across the width of the subject's upper torso and thighs. The quick release straps will be located to the side so that the subject may release him/herself.