Stated Preferences for Ecotourism Alternatives On the Standing Rock Sioux Indian Reservation

Despite favorable locations and the potential for economic development, Native American tribes have not developed their ecotourism markets substantially. This paper presents a choice experiment analysis of potential tourist and local resident preferences for alternative ecotourism development scenarios for the Standing Rock Sioux Indian Reservation. The choice experiments elicitation featured attributes of both cultural and nature-based tourist attractions. Survey results demonstrated that visitors interviewed at powwows had significantly different preferences from those interviewed at local tourist attractions. Results from all samples showed positive preferences towards an amphitheater, a nature trail, and a bison meal, and no preference toward an ATV trail. Non-powwow tourists had significant willingness to pay for a number of potential attractions, including nature trails, a road through the bison pasture, and an interpretive center with amphitheatre show.choice experiments, ecotourism, Native Americans, Standing Rock Sioux, Resource /Energy Economics and Policy,

Radio frequency and capacitive sensors for dielectric characterization of low-conductivity media

Low-conductivity media are found in a vast number of applications, for example as electrical insulation or as the matrix polymer in high strength-to-weight ratio structural composites. In some applications, these materials are subjected to extreme environmental, thermal, and mechanical conditions that can affect the material\u27s desired performance. In a more general sense, a medium may be comprised of one or more layers with unknown material properties that may affect the desired performance of the entire structure. It is often, therefore, of great import to be able to characterize the material properties of these media for the purpose of estimating their future performance in a certain application. Low-conductivity media, or dielectrics, are poor electrical conductors and permit electromagnetic waves and static electric fields to pass through with minimal attenuation. The amount of electrical energy that may be stored (and lost) in these fields depends directly upon the material property, permittivity, which is generally complex, frequency-dependent and has a measurable effect on sensors designed to characterize dielectric media. In this work, two different types of dielectric sensors: radio frequency resonant antennas and lower-frequency (\u3c1 MHz) capacitive sensors, are designed for permittivity characterization in their respective frequency regimes. In the first part of this work, the capability of characterizing multilayer dielectric structures is studied using a patch antenna, a type of antenna that is primarily designed for data communications in the microwave bands but has application in the field of nondestructive evaluation as well. Each configuration of a patch antenna has a single lowest resonant (dominant mode) frequency that is dependent upon the antenna\u27s substrate material and geometry as well as the permittivity and geometry of exterior materials. Here, an extant forward model is validated using well-characterized microwave samples and a new method of resonant frequency and quality factor determination from measured data is presented. Excellent agreement between calculated and measured values of sensor resonant frequency was obtained for the samples studied. Agreement between calculated and measured quality factor was good in some cases but incurred the particular challenge of accurately quantifying multiple contributions to loss from the sensor structure itself, which at times dominates the contribution due to the sample material. Two later chapters describe the development of capacitive sensors to quantify the low-frequency changes in material permittivity due to environmental aging mechanisms. One embodiment involves the application of coplanar concentric interdigital electrode sensors for the purpose of investigating polymer-matrix degradation in glass-fiber composites due to isothermal aging. Samples of bismaleimide-matrix glass-fiber composites were aged at several high temperatures to induce thermal degradation and capacitive sensors were used to measure the sensor capacitance and dissipation factor, parameters that are directly proportional to the real and imaginary components of complex permittivity, respectively. It was shown that real permittivity and dissipation factor decreased with increasing aging temperature, a trend that was common to both interdigital sensor measurements and standard parallel plate electrode measurements. The second piece of work involves the development of cylindrical interdigital electrode sensors to characterize complex permittivity changes in wire insulation due to aging-related degradation. The sensor was proven effective in detecting changes in irradiated nuclear power plant wiring insulation and in aircraft wiring insulation due to liquid chemical immersion. In all three cases, the results indicate a clear correlation of measured capacitance and dissipation factor with increased degradation

Factors affecting the distribution, abundance and chick survival of the Lapwing (<i>Vanellus vanellus</i>)

This thesis was conducted to investigate Lapwing Vanellus vanellus breeding ecology and its relationship with the modern agricultural landscape. Scientific research has suggested that changes in modern agricultural practices have been responsible for the declines in a suite of farmland bird species, including the Lapwing. Fieldwork was conducted over the breeding seasons of 1999 and 2000 over a range of farm locations in Shropshire and Staffordshire, with additional supplementary data obtained from a parallel study undertaken in Cambridgeshire. This research assessed the effectiveness of the ‘Lapwing Option’ (Option IB) in the pilot Arable Stewardship agrienvironment scheme. A total of 225 nests were located and monitored. There were few detectable effects of agricultural variables on clutch size, egg volume, intra-clutch egg size variation or hatching rates. Cultivation dates stipulated by Option IB avoided the peak nesting period for this population of Lapwings. At the start of the breeding season Lapwings selected a wide variety of crop types as nest sites, however, crop choice declined as the season progressed, with the majority of replacement nests on Option IB and spring crops. Lapwings were shown to select nest-sites that had a short, patchy sward structure. Nest survival was high, yet the most common causes of nest failure were predation and losses to agricultural operations. Losses on stubbles and spring cereals were primarily associated with agricultural operations. Nests that were greater than 50m distant fi*om a field boundary had a greater probability of survival than nests that were less than 50m away. Chick weight and condition were shown to be positively correlated with mean egg volume. There was no evidence that any of the measured agricultural variables had an effect on chick growth, condition or survival. Results show that chick survival was low and productivity estimates were less than that required to maintain population stability. Chicks that were known to have fledged had a better body condition index than chicks that had been predated. It was found that the variety of crop types used as foraging habitat declined as the season progressed. Option IB, set- aside and sugar beet were the latest crops that could be utilised by chicks. A variety of invertebrate taxa were found in faecal samples of chicks, with earthworms, beetles and spiders the most frequent. There was a positive relationship between the number of earthworms in the diet and chick age, chick condition and daily growth rates. Option IB appears to have a number of benefits for breeding Lapwing, although it does not address low chick survival. Further research is required to elucidate the key factors affecting chick survival and to develop management prescriptions to enhance breeding productivity

Electrical and capacitive methods for detecting degradation in wire insulation

Motivated by a need within the aerospace industry to detect and characterize degradation in the insulation of onboard wires, this thesis reports testing of several extant methods and development of novel capacitive sensors. This work focuses on measuring the electrical parameters resistance and capacitance that are directly related to the material parameters conductivity and permittivity, respectively, of the insulation. It is shown that the measured electrical parameters successfully indicate degradation in the wire insulation. Insulation resistance tests were performed on 17 wire samples, removed from various locations on a retired aircraft, and compared with those conducted on pristine wire samples, in order to assess any change in conductivity exhibited by degraded insulation. Timed resistance tests were also performed to determine the dielectric absorption of the insulation. Curved patch-electrode sensors were applied in order to measure the capacitance and dissipation factor of the same wires. Results from the resistive and capacitive tests both identified wire samples that were apparently significantly degraded, as indicated qualitatively by visual inspection. Further, a novel cylindrical interdigital capacitive sensor was developed. The interdigital sensor is designed with the goal of achieving a good signal-to-noise ratio, the lowest instrument error possible at 1 MHz, full circumferential coverage of the wire, and the ability to adjust the penetration depth of the electric field into the insulation layer by adjusting the separation of the sensor digits. With the aim, ultimately, of quantitative measurement of insulation complex permittivity, a numerical model was developed using a cylindrical Green\u27s function and the Method of Moments to calculate theoretically the capacitance of the interdigital sensor. Benchmark experiments were carried out on large-scale dielectric-coated conductive cylinders to test the validity of the model. Experimental results agreed with measured results to within 5% for sensor configurations with 22 and 30 digits of each polarization, tested on insulation polymers acetal copolymer, acrylic and polytetrafluoroethylene. A design method by which the penetration depth of the electric field into the insulation layer may be optimized is also introduced. Plans for future work, to develop interdigital capacitive sensors with a convenient hand-held clamp design for in-situ testing of aircraft wiring insulation, are also presented

Visual display including linked bubbles

A visual display including a container, liquidous fluid within the container, a source of gaseous fluid communicating with the liquidous fluid, and at least one binary bubble formed within the liquidous fluid in response to gaseous fluid entering the liquidous fluid. The liquidous fluid is preferably a polymer in water solution or a polymer in mineral oil or silicon oil solution. The binary bubble has two bulbous portions in fluid communication with each other through a neck. The binary bubbles may link together in a chain extending from the bottom of the container to the top of the liquidous fluid. In other constructions, the binary bubbles float up through the liquidous fluid and collapse into a large individual bubble. The display may also include a light emitting source and a filter for selectively changing the color of light emitted into the container.https://digitalcommons.mtu.edu/patents/1047/thumbnail.jp

An interdigital capacitive sensor for quantitative characterization of wire insulation

An interdigital capacitive sensor has been developed to characterize the permittivity of wire insulation. A theoretical model has been developed to calculate the capacitance of such a sensor that is in intimate contact with the surface of a double-layer cylindrical dielectric surrounding a conductive core. The cylindrical form of the electrostatic Green’s function due to an exterior point source is utilized, with the final capacitance value being calculated using the Method of Moments. Example calculations are performed and a field optimization method is developed to improve the sensing efficiency of the electrodes