A powerful new infrared array camera for the NASA Infrared Telescope Facility

We have just finished building a 1.0–5.5 m infrared array camera for the NASA Infrared Telescope Facility based upon the SBRC 256×256 InSb array. After a brief overview of the capabilities of the camera (named NSFCAM), we present some of the first images obtained with this new camera, including results obtained with our realtime shift & add speckle imaging mode.     

Low-Cost On-Site Treatment of Landfill Leachate Using Infiltration Beds: Preliminary Field Trial

A small-scale field experiment was carried out to demonstrate the effectiveness of using septic system -type infiltration beds for on-site treatment of landfill leachate. Using an infiltration bed with a 3-m-thick vadose zone of medium sand, and loaded at a rate 01 18 cm/day, a treatment efficiency of >99 percent was obtained for Fe, 94 percent for NH₄⁺, and 54 percent for dissolved organic carbon (DOC). Attenuation occurred during one- to two-day residency in the aerobic vadose zone (pore gas O₂ > 12 percent by volume) as a result of oxidation reactions that caused nitrification of NH₄⁺, convened Fe²⁺ to Fe³⁺ allowing subsequent precipitation of sparingly soluble Fe oxyhydroxide minerals, and biodegraded DOC. Attenuation of an aerobically degradable trace volatile organic compound (dichlorobenzene) was also noted, although other less degradable compounds (trichloroethylene and tetrachloroethylene) persisted.
Fe mineral precipitation caused a discontinuous hardpan layer to occur in the zone immediately below the infiltration pipes. However, this layer did not become impermeable or continuous enough to significantly impede infiltration during the 82-day experiment.
Advantages of this technology for leachate treatment are that it is low cost, it is simple to construct and operate. and treatment occurs on-site, avoiding the cost of transporting leachate off-site for treatment.     

Numerical Generation of Flow Nets — The FLOWNS Model

Abstract. A simple-to-use computer program (FLOWNS) has been developed for generating flow nets for any saturated rectangular domain with any combination of constant head or constant flux (including zero) boundary conditions. The program approximates with discrete values the continuous distributions of potential and stream function using finite-difference approximations of Laplace's equation. The hydraulic conductivity distribution may be anisotropic and/or heterogeneous. A contouring program is required to generate the final stream and equipotential lines.     

Permian ammonoids from Eastern Australia

Umbrella‐shaped objects, presumably fossils, were collected from the Lower Proterozoic Noltenius Formation at two localities about 80 miles south of Darwin. Radial and concentric forms are described morphologically, and their probable mode of origin is discussed.     

The impact of discharges from seafood processing on southeastern estuaries

A study to determine the impact of seafood packing and processing effluents discharged to southeastern estuarine waters was conducted in July and August of 1979. The environmental impact of current seafood processing wastes on Georgia’s estuaries appears to be minimal when compared with the natural organic load. One large estuary demonstrated a high residual capacity to receive processing effluents without significant change. The BOD load from shrimp thawing, peeling, sorting, and cleaning operations at a large seafood processing plant was shown to be equivalent to the organic material generated by a 302 m² plot (57 ft×57 ft) of salt marsh. NH₄?N levels were greater than, but the same order of magnitude as, natural runoff from marsh land.     

Stratigraphic Trapping of Spilled Jet Fuel Beneath the Water Table

Environmental conditions and the initial attempt to recover JP-4 jet fuel from a shallow aquifer at a tank farm in Hanahan, South Carolina, in 1975. allowed the jet fuel to become stratigraphically trapped below the water table. The trapped jet fuel remained an undetected source of dissolved hydrocarbon contamination in shallow ground water in the area for 17 years. The trapped jet fuel was located when a variety of chemical, hydrologic. geologic, and historical evidence led investigators to install and sample deeper wells. These findings emphasize the need to use an integrated approach lo evaluating the data when determining the extent of contamination and planning fuel recovery operations in a lithologically heterogeneous aquifer.     

New insights into the history and origin of the southern Maya block,SE México: U–Pb–SHRIMP zircon geochronology from metamorphic rocks of the Chiapas massif

The histories of the pre-Mesozoic landmasses in southern México and their connections with Laurentia, Gondwana, and among themselves are crucial for the understanding of the Late Paleozoic assembly of Pangea. The Permian igneous and metamorphic rocks from the Chiapas massif as part of the southern Maya block, México, were dated by U–Pb zircon geochronology employing the SHRIMP (sensitive high resolution ion microprobe) facility at Stanford University. The Chiapas massif is composed of deformed granitoids and orthogneisses with inliers of metasedimentary rocks. SHRIMP data from an anatectic orthogneiss demonstrate that the Chiapas massif was part of a Permian (∼ 272 Ma) active continental margin established on the Pacific margin of Gondwana after the Ouachita orogeny. Latest Permian (252–254 Ma) medium- to high-grade metamorphism and deformation affected the entire Chiapas massif, resulting in anatexis and intrusion of syntectonic granitoids. This unique orogenic event is interpreted as the result of compression due to flat subduction and accretionary tectonics. SHRIMP data of zircon cores from a metapelite from the NE Chiapas massif yielded a single Grenvillian source for sediments. The majority of the zircon cores from a para-amphibolite from the SE part of the massif yielded either 1.0–1.2 or 1.4–1.5 Ga sources, indicating provenance from South American Sunsás and Rondonian-San Ignacio provinces.     

Estimates of uncertainty in the prediction of past climatic variables

Fitting a regression line to a set of measurements to investigate the relationship between a proxy estimate of past climate and known climatic parameters is a routine procedure. It is generally accepted that the higher the correlation between parameters, the more reliable the reconstruction. However, there is a lack of published work upon what correlation is the minimum acceptable value. Simulated data was used to demonstrate that the relationship between proxy values and the climatic data are adversely affected by falling correlation, to the point where, in a training set consisting of 100 pairs of temperature and tree-ring proxies, the mean 95% confidence interval width for the reconstructed temperature exceeds the total range of temperatures in the training set at or below r = 0.65. This correlation is typical of that used in many climate-proxy reconstructions, and it suggests that understanding of past climate variability may be somewhat constrained.     

Light responses of Carex planostachys from various microsites in a Juniperus community

Juniperus communities are found on over 50 × 10⁶ ha in arid and semiarid habitats in southwestern North America. The drought tolerant sedge Carex planostachys occurs below the canopy in some of these communities. Cover and biomass of C. planostachys are high below the canopy and low in associated gaps. The purposes of this study were to investigate the temporal and spatial physiologic response of C. planostachys to abiotic changes, and determine it's light response characteristics from four contiguous microsites. Net photosynthesis was highest in spring when temperature was cooler and soil water higher, but low carbon uptake continued during summer drought. In addition, C. planostachys demonstrates a capacity to recover from extreme drought, despite water potential measured below ?9.0 MPa. Based on physiological light response curves and gas-exchange measurements, C. planostachys appears tolerant of shaded and full sun habitats. Light levels below the canopy were reduced compared to the gaps, but light saturation of C. planostachys did not change and net CO₂ uptake was only reduced slightly. Carbon uptake was coupled to light levels and not soil moisture. Observed differences in physiological attributes and variation in C. planostachys cover and biomass correspond to the presence or absence of the canopy. Low light compensation points, coupled with reduced respiratory demand, maximize photosynthetic gain in low light microsites. C. planostachys appears to acclimate across a range of light regimes, suggesting photosynthetic plasticity, allowing growth and survival in diverse light microhabitats. C. planostachys, tolerant of drought, appears anisohydric and demonstrates a capacity to acclimate to sun and shaded habitats, which could allow it to occur across a wider range of arid areas.