Sensing using Specialty Optical Fibers

Fiber optic based sensing is a growing field with many applications in civil and aerospace engineering, oil and gas industries, and particularly in harsh environments where electronics are not able to function. Optical fibers can be easily integrated into structures, are immune to electromagnetic interference, can be interrogated from remote distances, and can be multiplexed for distributed measurements. Because of these properties, specialty fiber designs and devices are being explored for sensing temperature, strain, pressure, curvature, refractive index, and more. Here we show a detailed analysis of a multicore fiber (MCF) for sensing, including its design and optimization in simulation, as well as experimental operation when used as sensor. The multicore fiber sensor\u27s performance as a function of temperature, strain, bending, and acoustic waves are all explored. The MCF sensors are shown to be able to withstand temperatures up to 1000°C, making them suitable to be harsh environment sensors. Additionally, a simple method for increasing the sensitivity of the MCF to longitudinal force is shown to multiple the sensitivity of the MCF sensor by a factor of seven. Also, a configuration for decoupling force and temperature will be presented. Finally, a developing all-fiber device, a photonic lantern, will be shown in conjunction with the MCF in order to increase sensitivity, add directional sensitivity, and lower the cost of the sensor interrogation for bending measurements. In addition to the multicore fiber, an analysis of anti-resonant hollow core fiber (ARHCF) is also presented. The fibers\u27 design-dependent propagation losses are explored, as well as their higher order mode content. Also, a potential application of an ARHCF for an in-fiber Raman air sensor is introduced, and the design optimization in simulation is shown

Nebraska Farm Real Estate Market Highlights 2010-2011

The Department of Agricultural Economics, UNL has conducted a state-wide study of agricultural land markets each year for the past 33 years. The state is richly endowed with productive agricultural land, which results in Nebraska ranking among the top five states in agricultural production. A primary aspect of the UNL land market series is an annual land market panel survey conducted February 1 of each year. In the 2011 survey, some 130 panel reporters from across the state provided their professional insight into the dynamics of the agricultural land markets in their areas of the state. These individuals are closely associated with the land markets through their professions as agricultural real estate appraisers, professional farm managers, agricultural lenders, etc. Moreover, continuity of the survey is maintained over the years as the vast majority of reporters have responded annually for a number of years. The reporters provide point-in-time estimates of current agricultural land values and cash rents as well as more detailed information of actual agricultural real estate sales that have occurred over the previous year. Comparing these current measures against previous years’ results provide valuable trend indicators of this dynamic market. The historical UNL data series for agricultural values going back to 1978 and agricultural cash rents back to 1981 are included in the appendix

PTSD Detection Device

This project focuses on improving the well being and independence of veterans struggling with Post Traumatic Stress Disorder (PTSD). Service dogs are vital for a veteran in daily routines and for emotional support. They are trained to prevent their veteran from experiencing a PTSD episode, but the service dog could be preoccupied with another task or in an environment that makes it difficult for them to read their veteran. To fix this issue, we have developed a device for the veteran and a device for the service dog. The veteran\u27s device is wearable and will be able to track important biometric information to detect if a PTSD episode will occur. The device will factor things like a sudden increase in heart rate and if certain markers are met that hints towards a PTSD episode, the device will then send a signal to the device on the service dog. The device on the dog will read that signal and start vibration motors in the dog\u27s vest to alert it. It is essential that nobody in the surrounding area knows that the device is functioning to respect the veteran\u27s privacy and self confidence. It is also very important to enable a bluetooth connection between the two devices to prevent any accessibility issues. The main goal for this project is to develop a working prototype that does not restrict the veteran or service dog in any way

Magnetohydrostatic atmospheres

We show that the atmospheric and magnetic height variations are coupled in general MHS equilibria with gravity when isolated thin non-force-free flux tubes are present. In gas-dominated environments, as in stellar photospheres, flux tubes must expand rapidly with height to maintain pressure balance with the cool surroundings. But in magnetically dominated environments, as in stellar coronae, the large-scale background magnetic field determines the average spreading of embedded flux tubes, and rigidly held flux tubes {\it require} a specific surrounding atmosphere with a unique temperature profile for equilibrium. The solar static equilibrium atmosphere exhibits correct transition-region properties and the accepted base coronal temperature for the sun's main magnetic spherical harmonic. Steady flows contribute to the overall pressure, so equilibria with accelerated wind outflows are possible as well. Flux tubes reflect a mathematical degeneracy in the form of non-force-free fields, which leads to coupling in general equilibrium conditions. The equilibrium state characterizes the system average in usual circumstances and dynamics tend to maintain the MHS atmosphere. Outflows are produced everywhere external to rigidly held flux tubes that refill a depleted or cool atmosphere to the equilibrium gas profile, heating the gas compressively.Comment: 12 pages, 5 figures, accepted by A&