Quantifying the Influence of Near-Surface Water-Energy Budgets on Soil Thermal Properties Using a Network of Coupled Meteorological and Vadose-Zone Instrument Arrays in Indiana, USA

Poster presented at American Geophysical Union Meeting, 2012.Weather stations that collect reliable, sustained meteorological data sets are becoming more widely distributed because of advances in both instrumentation and data server technology. However, sites collecting soil moisture and soil temperature data remain sparse with even fewer locations where complete meteorological data are collected in conjunction with soil data. Thanks to the advent of sensors that collect continuous in-situ thermal properties data for soils, we have gone a step further and incorporated thermal properties measurements as part of hydrologic instrument arrays in central and northern Indiana. The coupled approach provides insights into the variability of soil thermal conductivity and diffusivity attributable to geologic and climatological controls for various hydrogeologic settings. These data are collected to facilitate the optimization of ground-source heat pumps (GSHPs) in the glaciated Midwest by establishing publicly available data that can be used to parameterize system design models. A network of six monitoring sites was developed in Indiana. Sensors that determine thermal conductivity and diffusivity using radial differential temperature measurements around a heating wire were installed at 1.2 meters below ground surface— a typical depth for horizontal GSHP systems. Each site also includes standard meteorological sensors for calculating reference evapotranspiration following the methods by the Food and Agriculture Organization (FAO) of the United Nations. Vadose zone instrumentation includes time domain reflectometry soil-moisture and temperature sensors installed at 0.3-meter depth intervals down to a 1.8-meter depth, in addition to matric potential sensors at 0.15, 0.3, 0.6, and 1.2 meters. Cores collected at 0.3-meter intervals were analyzed in a laboratory for grain size distribution, bulk density, thermal conductivity, and thermal diffusivity. Our work includes developing methods for calibrating thermal properties sensors based on known standards and comparing measurements from transient line heat source devices. Transform equations have been developed to correct in-situ measurements of thermal conductivity and comparing these results with soil moisture data indicates that thermal conductivity can increase by as much as 25 percent during wetting front propagation. Thermal dryout curves have also been modeled based on laboratory conductivity data collected from core samples to verify field measurements, and alternatively, temperature profile data are used to calibrate near-surface temperature gradient models. We compare data collected across various spatial scales to assess the potential for upscaling near-surface thermal regimes based on available soils data. A long-term goal of the monitoring effort is to establish continuous data sets that determine the effect of climate variability on soil thermal properties such that expected ranges in thermal conductivity can be used to determine optimal ground-coupling loop lengths for GSHP systems

Monitoring near-surface thermal properties in conjunction with energy and moisture budgets to facilitate the optimization of ground-source heat pumps in the glaciated Midwest

This poster was presented at the American Geophysical Union Fall Meeting 2011, San Francisco, Calif., on December 7, 2011. It was part of IN33C, Geothermal energy research and discovery II posters session.By exploiting the near-surface heat reservoir, ground-source heat pumps (GSHP) represent an important renewable energy technology that can be further developed by establishing data sets related to shallow (<100m) thermal regimes. Although computer programs are available for GSHP installers to calculate optimal lengths and configurations of ground-coupling geothermal systems, uncertainties exist for input parameters that must first be determined for these models. Input parameters include earth temperatures and thermal properties of unconsolidated materials. Furthermore, thermal conductivity of sediments varies significantly depending on texture and moisture content, highlighting the need to characterize various unconsolidated materials under varying soil moisture regimes. Regolith texture data can be, and often are, collected for particular installations, and are then used to estimate thermal properties for system design. However, soil moisture and temperature gradients within the vadose zone are rarely considered because of the difficulty associated with collecting a sufficient amount of data to determine predominant moisture and temperature ranges. Six monitoring locations were chosen in Indiana to represent unique hydrogeologic settings and near-surface glacial sediments. The monitoring approach includes excavating trenches to a depth of 2 meters (a typical depth for horizontal GSHP installations) and collecting sediment samples at 0.3-meter intervals to determine thermal conductivity, thermal diffusivity, and heat capacity in the laboratory using the transient line heat source method. Temperature sensors are installed at 0.3-meter intervals to continuously measure thermal gradients. Water-content reflectometers are installed at 0.3, 1, and 2 meters to determine continuous volumetric soil moisture. In-situ thermal conductivity and thermal diffusivity are measured at 1.5 meters using a differential temperature sensor that measures radial differential temperature around a heating wire. Micrometeorological data (precipitation, insolation, ambient air temperature, relative humidity, and wind speed) are also collected to determine surface energy and water budgets that drive fluxes of energy and moisture in the shallow subsurface. By establishing continuous, year-round data, fluctuations in seasonal energy budgets and unsaturated zone soil moisture can be considered such that GSHP system designers can establish accurate end members for thermal properties, thereby optimizing the ground-coupling component of GSHPs. These data will also provide empirical controls such that soil moisture and temperature regimes can be spatially distributed based on mapped soil units and hydrogeologic settings in Indiana

Evaluating Pennsylvania’s Newborn Hearing Screening Program

Scope: Pennsylvania’s Newborn Hearing Screening (NBHS) program is a critical state-run program that is imperative for the goal of early identification of children with hearing loss. The purpose of this study was to evaluate Pennsylvania’s administration of the NBHS, as well as analyze Pennsylvania’s adherence to the JCIH 1-3-6 Guidelines. Methodology: Records from 131,832 newborns born in 2018 were analyzed for this study. Descriptive statistics were utilized to determine outcomes related to the JCIH guidelines. Prevalence of hearing loss and odds ratios were calculated to determine risks of hearing loss in the 2018 newborn population. Conclusions: The findings suggest that Pennsylvania has a strong adherence to the 1-3-6 guidelines, with an average timeframe of 3.04 days from birth to screening, 75.39 days from birth to diagnosis, and 174.2 days from birth to early intervention enrollment. The information from this study will be used for future program development, as well as to identify areas of improvement within the Commonwealth

Indiana Shallow Geothermal Monitoring Network: A Test Bed for Optimizing Ground-Source Heat Pumps in the Glaciated Midwest

This poster was presented at the 46th Annual Meeting of the North-Central Section of the Geological Society of America, April 23-24, 2012.Ground-source heat pumps (GSHP) represent an important technology that can be further developed by collecting data sets related to shallow thermal regimes. Computer programs that calculate the required lengths and configurations of GSHP systems use specific input parameters related to the soil properties to enhance the accuracy of models and produce efficient system designs. The thermal conductivity of sediments varies significantly depending on texture, bulk density, and moisture content, and it is therefore necessary to characterize various unconsolidated materials under a wide range of moisture conditions. Regolith texture data are collected during some installations to estimate thermal properties, but soil moisture and temperature gradients within the vadose zone are rarely considered due to the difficulty of collecting sufficient amounts of data. Six monitoring locations were chosen in Indiana to represent unique hydrogeological settings and glacial sediments. Trenches were excavated to a depth of 2 meters (a typical depth for horizontal GSHP installations) and sediment samples were collected at 0.3-meter intervals for a laboratory analysis of thermal conductivity, thermal diffusivity, bulk density, and moisture content. Temperature sensors and water-content reflectometers were installed in 0.3-meter increments to monitor changes in temperature and soil moisture with depth. In-situ thermal conductivity and thermal diffusivity were measured at 1.5-meters using a sensor that detects radial differential temperature around a heating wire. Micrometeorological data were also collected to determine the surface conditions and water budgets that drive fluxes of energy and moisture in the shallow subsurface. Preliminary results indicate that increases in water content can increase thermal conductivity by as much as 30% during wetting front propagation. Although there is a change in temperature associated with the infiltration of wetting fronts, thermal conductivity appears to be independent of soil temperature. By establishing continuous data sets, fluctuations in seasonal energy budgets and unsaturated zone soil moisture can be determined. This information can then be used to establish accurate end members for thermal properties and improve the efficiency of geothermal systems

Release of mercury halides from KCl denuders in the presence of ozone

KCl-coated denuders have become a standard method for measurement of gaseous oxidized mercury, but their performance has not been exhaustively evaluated, especially in field conditions. In this study, KCl-coated and uncoated quartz denuders loaded with HgCl&lt;sub&gt;2&lt;/sub&gt; and HgBr&lt;sub&gt;2&lt;/sub&gt; lost 29–55% of these compounds, apparently as elemental mercury, when exposed to ozone (range of 6–100 ppb tested). This effect was also observed for denuders loaded with gaseous oxidized mercury at a field site in Nevada (3–37% of oxidized mercury lost). In addition, collection efficiency decreased by 12–30% for denuders exposed to 50 ppb ozone during collection of HgCl&lt;sub&gt;2&lt;/sub&gt;. While data presented were obtained from laboratory tests and as such do not exactly simulate field sampling conditions, these results indicate that the KCl denuder oxidized mercury collection method may not be as robust as previously thought. This work highlights needs for further testing of this method, clear identification of gaseous oxidized mercury compounds in the atmosphere, and development of field calibration methods for these compounds

Release of mercury halides from KCl denuders in the presence of ozone

KCl-coated denuders have become a standard method for measurement of gaseous oxidized mercury, but their performance has not been exhaustively evaluated, especially in field conditions. In this study, KCl-coated and uncoated quartz denuders loaded with HgCl&lt;sub&gt;2&lt;/sub&gt; and HgBr&lt;sub&gt;2&lt;/sub&gt; lost 29–55% of these compounds, apparently as elemental mercury, when exposed to ozone (range of 6–100 ppb tested). This effect was also observed for denuders loaded with gaseous oxidized mercury at a field site in Nevada (3–37% of oxidized mercury lost). In addition, collection efficiency decreased by 12–30% for denuders exposed to 50 ppb ozone during collection of HgCl&lt;sub&gt;2&lt;/sub&gt;. While data presented were obtained from laboratory tests and as such do not exactly simulate field sampling conditions, these results indicate that the KCl denuder oxidized mercury collection method may not be as robust as previously thought. This work highlights needs for further testing of this method, clear identification of gaseous oxidized mercury compounds in the atmosphere, and development of field calibration methods for these compounds

Thermopower of Interacting GaAs Bilayer Hole Systems in the Reentrant Insulating Phase near ν=1\nu=1

We report thermopower measurements of interacting GaAs bilayer hole systems. When the carrier densities in the two layers are equal, these systems exhibit a reentrant insulating phase near the quantum Hall state at total filling factor $\nu=1$. Our data show that as the temperature is decreased, the thermopower diverges in the insulating phase. This behavior indicates the opening of an energy gap at low temperature, consistent with the formation of a pinned Wigner solid. We extract an energy gap and a Wigner solid melting phase diagram.Comment: to be published in Phys. Rev. Let