Effects of lithology on solution development in carbonate aquifers

Groundwater flow in karst aquifers is extremely difficult to predict because of the presence of solution-enlarged fractures and conduits in the bedrock. The location and volume of this solution development is the result of interrelated geologic, hydrologic and climatic factors. This paper examines lithologic properties which influence apparent solution rates in carbonate aquifers as indicated by weathered profiles in caverns. Rock samples collected from cavern entrances and walls in southwestern Missouri, U.S.A., were analyzed for grain size, sorting, percent quartz, percent magnesium carbonate, percent opaque minerals and percent acid-insoluble residue. Discriminant function analyses of these measurements show that grain size is the most important parameter in distinguishing the grouping of apparently resistant and non-resistant samples. Small grain size favors dissolution and strongly influences the relief of the weathered profile regardless of rock composition. Significant variability in magnesium carbonate content may also affect the apparent solution rate but to a lesser degree than grain size.     

Assessment of radionuclide transport uncertainty in the unsaturated zone of Yucca Mountain

The present study assesses the uncertainty of flow and radionuclide transport in the unsaturated zone at Yucca Mountain using a Monte Carlo method. Matrix permeability, porosity, and sorption coefficient are considered random. Different from previous studies that assume distributions of the parameters, the distributions are determined in this study by applying comprehensive transformations and rigorous statistics to on-site measurements of the parameters. The distribution of permeability is further adjusted based on model calibration results. Correlation between matrix permeability and porosity is incorporated using the Latin Hypercube Sampling method. After conducting 200 Monte Carlo simulations of three-dimensional unsaturated flow and radionuclide transport for conservative and reactive tracers, the mean, variances, and 5th, 50th, and 95th percentiles for quantities of interest (e.g., matrix liquid saturation and water potential) are evaluated. The mean and 50th percentile are used as the mean predictions, and their associated predictive uncertainties are measured by the variances and the 5th and 95th percentiles (also known as uncertainty bounds). The mean predictions of matrix liquid saturation and water potential are in reasonable agreement with corresponding measurements. The uncertainty bounds include a large portion of the measurements, suggesting that the data variability can be partially explained by parameter uncertainty. The study illustrates propagation of predictive uncertainty of percolation flux, increasing downward from repository horizon to water table. Statistics from the breakthrough curves indicate that transport of the reactive tracer is delayed significantly by the sorption process, and prediction on the reactive tracer is of greater uncertainty than on the conservative tracer because randomness in the sorption coefficient increases the prediction uncertainty. Uncertainty in radionuclide transport is related to uncertainty in the percolation flux, suggesting that reducing the former entails reduction in the latter.     

Legal and environmental concerns affecting electric utility involvement in cogeneration

The National Energy Act of 1978 included cogeneration as one of the leading strategies to help solve the nation's energy problems. As a result many new regulations have been formulated to encourage the development of industrial cogeneration facilities. These regulations are aimed at reducing oil imports, conserving nonrenewable resources, and preserving air quality. The electric utilities are uncertain whether the regulations will accomplish these goals. They are concerned that the regulations will lead to the proliferation of small industrial cogeneration facilities giving rise to increased air pollution and other adverse environmental impacts. The utilities are also concerned that, because of the way the regulations are written, they will discourage the electric utilities from fully participating in the cogeneration process.     

Coronal disturbances

A fast coronal transient event was observed simultaneously on 17 February 1972 by the Sacramento Peak Observatory 6-in. λ 5303 filter coronagraph and the High Altitude Observatory K-coronameter. We interpret the rapid opening of green line structure cospatial with the disappearance of a white light streamer as material motion of iron ions and electrons. Together with the subsequent two-fold increase in K-corona brightness in an adjacent region, this is taken as evidence of a transference of electrons to a new streamer in a realignment of magnetic flux tubes accompanying a flare.     

Equatorial coronal arches and geomagnetic disturbance

Central-meridian passage of coronal equatorial arches is followed, statistically, after about 7 days by geomagnetic disturbance. Sector-boundary crossings at Earth are most likely to occur 5 days after arch CMP, while metric noise sources cluster at the location of the arches. This agrees with the location of the noise sources relative to sector boundaries described by Sakurai and Stone (1971), rather than with that found by Martres et al. (1970) for 1964 and 1966, and may indicate evolution of the relation between coronal and interplanetary structure. We looked for, but did not find, clustering of coronal arches at a particular phase of the Olsen rotation scheme.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

Axial rotation, orbital revolution and solar spin–orbit coupling

The orbital motion of the Sun has been linked with solar variability, but the underlying physics remains unknown. A coupling of the solar axial rotation and the barycentric orbital revolution might account for the relationships found. Some recent published studies addressing the physics of this problem have made use of equations from rotational physics in order to model particle motions. However, our standard equations for rotational velocity do not accurately describe particle motions due to orbital revolution. The Sun's orbital motion is a state of free fall; in consequence, aside from very small tidal motions, the associated particle velocities do not vary as a function of position on or within the body of the Sun. In this note, I describe and illustrate the fundamental difference between particle motions in rotation and revolution, in order to dispel some part of the confusion that has arisen in the past and that which may yet arise in the future. This discussion highlights the principal physical difficulty that must be addressed and overcome by future dynamical spin–orbit coupling hypotheses.     

An Approach to Quantify the Heat Wave Strength and Price a Heat Derivative for Risk Hedging

Mitigating the heat stress via a derivative policy is a vital financial option for agricultural producers and other business sectors to strategically adapt to the climate change scenario. This study has provided an approach to identifying heat stress events and pricing the heat stress weather derivative due to persistent days of high surface air temperature (SAT). Cooling degree days (CDD) are used as the weather index for trade. In this study, a call-option model was used as an example for calculating the price of the index. Two heat stress indices were developed to describe the severity and physical impact of heat waves. The daily Global Historical Climatology Network (GHCN-D) SAT data from 1901 to 2007 from the southern California, USA, were used. A major California heat wave that occurred 20-25 October 1965 was studied. The derivative price was calculated based on the call-option model for both long-term station data and the interpolated grid point data at a regular 0.1 ×0.1 latitude-longitude grid. The resulting comparison indicates that (a) the interpolated data can be used as reliable proxy to price the CDD and (b) a normal distribution model cannot always be used to reliably calculate the CDD price. In conclusion, the data, models, and procedures described in this study have potential application in hedging agricultural and other risks.