Physical Sciences and Mathematics Commons^™

Degradation Kinetics Of Aromatic Organic Solutes Introduced Into A Heterogeneous Aquifer, Wg Macintyre, M Boggs, Cp Antworth, Tb Stauffer

VIMS Articles

Degradation rates of benzene, p-xylene, naphthalene, and o-dichlorobenzene have been measured in a heterogeneous, unconfined aquifer during a pulse injection experiment at Columbus Air Force Base, Columbus, Mississippi. Dissolved oxygen in the pulse plume maintained aerobic conditions. Degradation kinetics calculated from the complete field data set were approximately first order with the following rate constants: benzene, 0.0070 d-1; p-xylene, 0.0107 d-1; naphthalene, 0.0064 d-1; and o-dichlorobenzene, 0.0046 d-1. Reaction rates were also calculated from a near-field subset of the data using a model based on the hydrologic characteristics of the aquifer. Shapes of the degradation rate curves were consistent with …

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And Chincoteague Bay - 1992, Robert Orth, Judith F. Nowak, Gary F. Anderson, Jennifer R. Whiting

Reports

No abstract provided.

Plowing Through The Muck: A Review Of Wetland Assessment I Evaluation Methods, Melissa Chaun, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Order And Chaos In Semiconductor Microstructures, W. A. Lin, John B. Delos, Robert E. Jensen

Arts & Sciences Articles

The semiclassical theory of ballistic electron transport in semiconductor microstructures provides a description of the quantum conductance fluctuations in terms of the classical distributions for the lengths and directed areas of the scattering trajectories. Because the classical dynamics differs for integrable (circular) and chaotic (stadium) scattering domains, experimental measurements of the conductance of these microstructures provide a unique probe of the quantum properties of classically regular and chaotic systems. To advance these theoretical and experimental studies we compare geometrical formulas for the classical distributions of lengths and areas with numerical simulations for microstructures examined in recent experiments, we assess the …

Photoabsorption Spectra Of Atoms In Parallel Electric And Magnetic Fields, J. M. Mao, K. A. Rapelje, S. J. Blodgett-Ford, John B. Delos, A. König, H. Rinneberg

Arts & Sciences Articles

Measurements have been made of the absorption spectrum of Ba from the 6s6p 1P1 level to states near the ionization threshold in parallel electric and magnetic fields. The absorption spectrum shows oscillations superposed on a smooth background. Each oscillation is correlated with a closed orbit of the electron. At strong electric fields, trajectories are regular, and closed orbits form orderly patterns. For weak electric fields, trajectories are chaotic, and many more closed orbits are present. Many of these are produced by bifurcations as the electric field is reduced.

Virginia Beach Offshore Sediment Study, C. R. Berquist Jr., Naomi Gomillion

Reports

This investigation was initiated from discussions among members of the Minerals Management Service-Virginia Task Force in an effort to locate a nearby and offshore source of beach-quality sand for the resort strip at Virginia Beach. Because of the increasing difficulty of relying upon land-based material, attention has been focused on investigating offshore sources. Previous work (Kimball and others, 1991) suggests an offshore deposit of beach-quality sands is located on a shoal between 3 and 8 km east of Sandbridge. Planned vibracoring on this shoal during the fall of 1993 should establish the viability of the sand occurrence. Although material from …

Data Report : Hypoxia In The James River, 1992, G. M. Sisson, A. Y. Kuo, Bruce Neilson, Nancy C. Wilson

Reports

As part of the hypoxia program of the Virginia Chesapeake Bay Initiatives, the Department of Physical Sciences of the Virginia Institute of Marine Science (VIMS) conducted a series of measurements around the mouth of the James River estuary. The measurements were made in the summer of 1992. Two types of measurements were conducted: measurements at moored stations and measurements by slackwater surveys. The former collected data for investigation of dissolved oxygen (DO) variation, and associated physical parameters, in an intratidal time scale, as well as for studying the vertical distributions of the measured parameters. The latter collected data for spatial …

Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1992 : A Report To The Virginia Department Of Environmental Quality, Kevin Curling, Rodney Jackson, Bruce Neilson

Reports

The Chesapeake Bay Water Quality Monitoring Program (WQMP) has three main objectives: (1) characterization of water quality conditions, (2) detection of temporal trends in water q1llality, and (3) crr.ation of a data base that furthers our understanding of the proceses that control water quality in the Chesapeake Bay system. The purpose of this report is to characterize water quality conditions in the Virginia portion of Chesapeake Bay during the 1992 water year, which runs from October 1991 through September 1992. These monitoring efforts have been conducted with funding from the US Environmental Protection Agency and the Commonwealth of Virginia.

Natural Resource Management In Coastal Virginia, Pamela Mason, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1991 : A Report To The Virginia Water Control Board, Kevin Curling, Bruce Neilson

Reports

The purpose of this report is to characterize water quality conditions during the 1991 water year, October 1990 through September 1991. Most information is provided in graphical format and only data for the Virginia portion of Chesapeake Bay is included. No interpretation is included, since data analysis is the stated purpose of several other reports. This report and companion data reports provide to both scientists and managers ready access to a portion of the data. It is possible, for example, to quickly examine seasonal patterns, compare conditions at two stations, or see if surface and bottom conditions differ significantly. Trends, …

Cape Charles Public Beach Assessment Report, C. Scott Hardaway Jr., Donna A. Milligan, George R. Thomas

Reports

No abstract provided.

Hypoxia In The York River, 1991, A. Y. Kuo, Bruce Neilson, J. M. Brubaker, E. P. Ruzecki

Reports

This data report describes field studies conducted during the summer of 1991 by the Virginia Institute of Marine Science (VIMS) when both the physical environment and the dissolved oxygen regime were monitored, with the objective of better understanding how physical transport processes affect DO. The 1991 data sets will be presented here. Analysis and interpretation of the data is the subject of other scientific reports.

Data Base Development For Characterizing Contaminated Sediments In The Chesapeake Bay Region, Gary F. Anderson, Caroline Brouwer-Riel, Maynard M. Nichols

Reports

This project is one component of the U.S. Geological Survey's National Coastal Geology Program directed to polluted sediments. Its long-term aim is to develop a comprehensive database on estuarine contaminated sediments that provides a summary of information and a digital reference source of detailed and readily accessible data. It focuses on Chesapeake Bay because there is a wealth of data on bottom sediments and sedimentary contaminants. However, this data is fragmented, uncollated and dispersed in many papers, books, reports, files and documents, often local sources, outside the mainstream of national consideration and scientific knowledge. Without an organized body of data, …

Photodetachment Cross Section Of H- In Crossed Electric And Magnetic Fields. Ii. Quantum Formulas And Their Reduction To The Result Of The Closed-Orbit Theory, Aaron D. Peters, John B. Delos

Arts & Sciences Articles

In this, the second of two papers, we derive general quantum formulas for the photodetachment cross section for H− in perpendicular electric and magnetic fields. The results are valid for any polarization and can be reduced to the semiclassical results of the first paper [A. D. Peters and J. B. Delos, Phys. Rev. A 47, 3020 (1993)]: a smooth background plus oscillatory terms. This connection between the quantum and semiclassical results is made using a stationary-phase approximation and it is shown that each stationary-phase point corresponds to a closed orbit.

Photodetachment Cross Section Of H- In Crossed Electric And Magnetic Fields. I. Closed-Orbit Theory, Aaron D. Peters, John B. Delos

Arts & Sciences Articles

In this, the first of two papers, we obtain a simple analytic formula for the photodetachment cross section of H− in crossed electric and magnetic fields. The three-dimensional semiclassical approximation predicts oscillations in the spectrum and these oscillations are correlated with closed classical orbits. In the following paper [A. D. Peters and J. B. Delos, Phys. Rev. A 47, 3036 (1993)] we derive fully-quantum-mechanical formulas for the cross section in perpendicular electric and magnetic fields and show how these results can be reduced to the semiclassical results of this paper.

Development Of "No Discharge" Zones In Virginia Tidal Waters Phase I, Center For Coastal Resources Management, Virginia Institute Of Marine Science

Reports

he Commonwealth of Virginia currently has no regulations in effect to restrict the discharge of waste from vessels in state waters. This poses concern as Virginia continues its efforts to improve water quality in the Chesapeake Bay. The degradation of critical environmental habitat is accelerated by the introduction of waste, which in turn threatens the ecological, aesthetic, and commercial values of Virginia's waters. The purpose of this project is two-fold. First a comprehensive review of regulatory statutes in states enforcing "no discharge" zones (NDZ) was conducted. This product is delivered as a separate document. Second, a large-scale inventory of environmentally …

Status Of The Major Oyster Diseases In Virginia 1992 A Summary Of The Annual Monitoring Program, Eugene M. Burreson

Reports

No abstract provided.

An Assessment Of Aquatic Wildlife Utilization Between Created And Natural Tidal Salt Marshes, Kirk J. Havens, Lyle M. Varnell, Virginia Instiute Of Marine Science, Wetlands Program

Reports

No abstract provided.

The Progression Of "No Discharge Zone" Status In Water Bodies Across The Continental United States, Melissa Chaun

Reports

No abstract provided.

A Proposed Comprehensive Conservation And Management Plan For The Ungranted State Lands In Accomack And Northampton Countie, N. Bartlett Theberge, Pamela J. Nestell, Susan W. Carter

Reports

The goal of this management plan is to conserve and manage the fragile and dynamic coastal habitat and resources subject to this plan while accommodating compatible public uses.

To date 28,507 acres of ungranted state lands have been identified in Accomack and Northampton Counties. The purpose of this plan 1s to develop a comprehensive conservation and management strategy for these state owned beaches marshes, meadowlands, commons, and other coastal lands which constitute a fragile and dynamic natural coastal resource of the Commonwealth of Virginia.

Sediment Characterization Of South Atlantic Systems, Maynard M. Nichols

Reports

The estuarine systems selected are from the NOAA National Estuarine Inventory in the EMAP Virginian Province (Figure 1). The principal spatial unit of each system is the estuarine drainage area (EDA) defined in the NEI data atlas (U.S. NOAA, 1985). The sediment and contaminant distributions embrace the estuarine bottom area, i.e. from the head of tides to the mouth where the estuary meets the ocean, bay or sound as determined by physiographic features (U.S. NOAA, 1985). Data coverage embraces whole estuaries and farfield distributions. Chart scales are smaller than 1:80,000 andchart units larger thaqn 0.1 square kilometer.

Variate Generation For Nonhomogeneous Poisson Processes With Time Dependent Covariates, Li-Hsing Shih, Lawrence Leemis

Arts & Sciences Articles

Algorithms are developed for generating a sequence of event times from a nonhomogeneous Poisson process that is influenced by the values of covariates that vary with time. Closed form expressions for random variate generation are shown for several baseline intensity and link functions. Two specific models linking the baseline process to the general model are considered: the accelerated time model and the proportional intensity model. In the accelerated time model, the cumulative intensity function of a nonhomogeneous Poisson process under covariate effects is [formula], where z is a covariate vector, ⋀0(t) is the baseline cumulative intensity function and …

Identification Of Historic Locations Of Aeschynomene Virginica Within The Tidal Freshwater Zone Of The Pamunkey River, Virginia : Final Report, James E. Perry

Reports

The historical distribution and population densities of a federal listed threatened plant species, the northern joint vetch (Aeschynomene virginica), was determined and mapped in the tidal regions of the Pamunkey River, Virginia, where a potential water withdrawal structure is being evaluated.

Nutrient Limitation In The Chesapeake Bay : Nutrient Bioassays In The Virginia Bay System: Final Report, Leonard W. Haas, Richard L. Wetzel

Reports

Nutrient enrichment bioassays were conducted on water samples collected from six stations in the Virginia portion of the Chesapeake Bay system on a monthly basis over a year. Two stations were located in the tidal freshwater portions of the Rappahannock and James Rivers, at the mouths of these rivers and in the mainstem of the Bay. The purpose of the experiments was to determine the spatial and temporal pattern of nutrient limitation of phytoplankton growth.

Effects Of Nutrient Enrichment On Natural And Transplanted Salt Marshes In Virginia : A Literature Review With Management Recommendations - Final Report, R. D. Rheinhardt, J. D. Perry

Reports

This study was initlated in response to a request by SEAS to review their technical recommendations concerning the fertilization of tidal salt marshes and determine whether those recommendations are sound in light of current scientific knowledge. The intention of this analysis was to determine whether benefits are derived from applying nutrients to marshes, and if so, whether those benefits outweigh the costs associated with the potential pollution of Chesapeake Bay's tidal waters.

To provide insight into the effects of adding fertilizers to salt marshes, the scientific literature was examined from four perspectives:

1) the dynamics of ·nutrient cycling in natural …

Chesapeake Bay Wave Climate : Thimble Shoal Light Wave Station, Report And Summary Of Wave Observations, October 8, 1990 Through August 22, 1991 And Chesapeake Light Tower - Vims Star Gage Test Measurements And Evaluation, July, August, October 1991, John D. Boon, D. A. Hepworth, K. D. Suh, F. H. Farmer

Reports

This report also presents a description of a directional wave gaging system, known as a "Star" gage, that is designed for long-term, low-maintenance operation both within and immediately outside the Chesapeake Bay entrance area. This development was prompted by our dependence to date on the single-point, PUV-type directional wave gage described below. While ideally suited for short-term investigative studies at different sites, the PUV directional wave gage requires field service visits at monthly intervals to maintain adequate performance and uninterrupted operation. A prototype Star gage system was constructed and field tested to evaluate its potential use as a long-term and …

Wetlands Guidelines, Department Of Wetlands Ecology, Virginia Institute Of Marine Science, Habitat Management Division, Virginia Marine Resources Commission

Reports

No abstract provided.

Sediment Processes Monitoring Data Report For Calendar Year 1989, Cheol Mo, Bruce Neilson, Richard L. Wetzel

Reports

Pairs of particle interceptor traps were deployed at three depths - 3, 6, and 9 meters with deployment intervals typically lasting about two weeks. At times of deployment and retrieval, profiles of water temperature, salinity and dissolved oxygen content were made and water samples were collected at trap depths. Bottom sediments also were collected and a sub-sample of the surficial sediments taken. Water samples, bottom sediments, and the materials collected in the traps were returned to the Virginia Institute of Marine Sciences for analysis. The data collected during both 1988 and 1989 are presented in the appendices. Both 1988 and …

Distribution Of Aeschynomene Virginica In The Scotland Landing Region Of The Mattaponi River, Virginia, James E. Perry

Reports

The distribution and population densities of a federal listed threatened plant species, the northern joint vetch (Aeschynomene virginica), was determined and mapped in the vicinity of a proposed Mattaponi River water withdrawal structure. The proposed study was intended to determine the size, limits, and density of extant populations of the northern joint vetch in the project area, and to investigate the possible impacts the project may have on the extant populations. Where necessary, . possible mitigation procedures are discussed.

Investigation Of Potential Distribution Of Aeschynomene Virginica In The Tidal Wetlands Of Ware Creek, Virginia : Final Report, James E. Perry

Reports

The distribution and population densities of a federal listed threatened plant species, the northern joint vetch (Aeschynomene virginica), was determined in the vicinity of the proposed Ware Creek Reservoir site in James City County and New Kent County, Virginia. The proposed study was intended to determine the size, limits, and density of extant populations of the northern joint vetch in the project area, and to investigate the possible impacts the project may have on the extant populations. Where necessary, possible mitigation procedures are discussed.