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2002

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Articles 3241 - 3270 of 3435

Full-Text Articles in Physical Sciences and Mathematics

Electronic And Structural Properties Of Rare Gas Cation Clusters, Jose Alejandro Gascon Jan 2002

Electronic And Structural Properties Of Rare Gas Cation Clusters, Jose Alejandro Gascon

LSU Doctoral Dissertations

We study structure and ground and excited state properties of rare gas cation clusters, Rg+N, for N=3-60. The main goal is to understand how the positive charge is delocalized over the cluster and the relationship between cluster geometry and delocalization. He+N, Ar+N, and Xe+N are selected as representatives of the rare gas elements. We perform Monte Carlo simulations to obtain finite temperature properties of the energy spectrum. The Hamiltonian of the system is based on a semi-empirical model whose parameters are obtained through the fitting of experimental and calculated …

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Synthesis And Properties Of Novel Macrocycles And Related Chromophoric Benzenoid Compounds, Jorge O. Escobedo Cordova Jan 2002

Synthesis And Properties Of Novel Macrocycles And Related Chromophoric Benzenoid Compounds, Jorge O. Escobedo Cordova

LSU Doctoral Dissertations

The synthesis and properties of some macrocyclic compounds of interest are presented. Resorcinarenes with functionalized conjugated rigid rods made of oligo-p-phenylenes would lead to an entirely new class of functional, soluble, well-defined architectures impacting a variety of multidisciplinary research efforts. The general synthetic design described in this document could be readly extrapolated to include other electronic systems such as heteroaromatics and polyenes. An extensive collaborative study of chromophore formation in resorcinarene solutions is also described here. The study reveals that upon oxidation, the reversible conversion to acyclic precursors occur first, and then these precursors undergo oxidation to quinoid-type compounds (xanthenes). …

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Scientific And Management Perspectives In Wetland Groundwater Hydrology, Lorna Veronica Inniss Jan 2002

Scientific And Management Perspectives In Wetland Groundwater Hydrology, Lorna Veronica Inniss

LSU Doctoral Dissertations

Wetland groundwater hydrology was investigated at different spatial scales to assess the usefulness of the information to coastal managers. Specific objectives were to: (1) review studies related to coastal groundwater discharge, evaluating techniques and identifying controls; (2) understand regional trends in groundwater flow along the U.S. East and Gulf coasts; (3) evaluate the applicability of naturally occurring radioisotopes as indicators of groundwater in a shallow deltaic system; and (4) evaluate groundwater-surface water exchange within Barataria Basin, Louisiana. Results of the review confirmed discharge estimates vary over several orders of magnitude, due to differences in precipitation and tidal prisms. In addition, …

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Synthesis, Characterization, And Applications Of Novel Pseudostationary Phases In Micellar Capillary Electrophoresis For Separation Of Chiral And Archiral Compounds H[Electronic Resource], Cevdet Akbay Jan 2002

Synthesis, Characterization, And Applications Of Novel Pseudostationary Phases In Micellar Capillary Electrophoresis For Separation Of Chiral And Archiral Compounds H[Electronic Resource], Cevdet Akbay

LSU Doctoral Dissertations

The research presented in this dissertation involves the synthesis, characterization, and the use of novel surfactants, including both micelles and vesicles, as pseudostationary phases in micellar capillary electrophoresis (MCE) for the separation of achiral and chiral compounds. Separation of environmental pollutants such as 2 to 6-ring polycyclic aromatic hydrocarbons (PAHs) was achieved using poly(sodium undecylenic sulfate). A baseline separation of all 16 PAHs was possible for the first time in MCE by a single-surfactant system. In addition, a surfactant with a phosphated head group, i.e., di(2-ethylhexyl)phosphate (DEHP), was also introduced as a novel pseudostationary phase for separation of 21 weakly …

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Actiononaias Ligamentina As A Biomonitor In The Green River: An Unique Approach For Analysis Of Environmental Impacts, Robert Kirkland Jan 2002

Actiononaias Ligamentina As A Biomonitor In The Green River: An Unique Approach For Analysis Of Environmental Impacts, Robert Kirkland

Masters Theses & Specialist Projects

Biomonitoring has become an important component in bioassessment programs. It is used to maintain high water quality standards, and determine contaminant levels and biological affects in areas that have been heavily disturbed. The objectives of this research were 1) to improve and apply certain modern biomonitoring techniques and 2) to locate possible contaminant sources affecting the flora and fauna of the Green River and of Mammoth Cave. Actinonaias ligamentina (Lamarck, 1819), a freshwater mussel, was used for interpretation of these impacts as well as refinement of biomonitoring techniques. The mussels were collected in the Lawler Bend region of the Green …

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The Crystal Packing Of 4,7-Dichloro- And 4,7-Dibromobenzo[C]Furazan 1-Oxide, D. Britton, Frank B. Mallory, C. W. Mallory Jan 2002

The Crystal Packing Of 4,7-Dichloro- And 4,7-Dibromobenzo[C]Furazan 1-Oxide, D. Britton, Frank B. Mallory, C. W. Mallory

Chemistry Faculty Research and Scholarship

The molecular structures of 4,7-dichlorobenzo[c]furazan 1-oxide, C6H2Cl2N2O2, (I), and 4,7-dibromobenzo[c]furazan 1-oxide, C6H2Br2N2O2, (II), are normal. Compound (I) occurs in two polymorphic forms. One polymorph contains one molecule in the asymmetric unit, organized into two-dimensional sheets involving intermolecular N...Cl and O...Cl interactions. The second polymorph has three molecules in the asymmetric unit, organized into two crystallographically different two-dimensional sheets with similar interactions. Compound (II) is isomorphous with the second polymorph of (I). The three two-dimensional sheets in the two polymorphs comprise a set of three two-dimensional polymorphic arrangements.

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Proceedings Of The First International Conference On Neutrosophy, Neutrosophic Logic, Neutrosophic Set, Neutrosophic Probability And Statistics, Florentin Smarandache Jan 2002

Proceedings Of The First International Conference On Neutrosophy, Neutrosophic Logic, Neutrosophic Set, Neutrosophic Probability And Statistics, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In 1960s Abraham Robinson has developed the non-standard analysis, a formalization of analysis and a branch of mathematical logic, that rigorously defines the infinitesimals. Informally, an infinitesimal is an infinitely small number. Formally, x is said to be infinitesimal if and only if for all positive integers n one has xxx < 1/n. Let &>0 be a such infinitesimal number. The hyper-real number set is an extension of the real number set, which includes classes of infinite numbers and classes of infinitesimal numbers. Let’s consider the non-standard finite numbers 1+ = 1+&, where “1” is its standard part and “&” its non-standard part, …

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Randomness And Optimal Estimation In Data Sampling, Florentin Smarandache, Mohammad Khosnevisan, Housila P. Singh, S Saxena, Sarjinder Singh Jan 2002

Randomness And Optimal Estimation In Data Sampling, Florentin Smarandache, Mohammad Khosnevisan, Housila P. Singh, S Saxena, Sarjinder Singh

Branch Mathematics and Statistics Faculty and Staff Publications

The purpose of this book is to postulate some theories and test them numerically. Estimation is often a difficult task and it has wide application in social sciences and financial market. In order to obtain the optimum efficiency for some classes of estimators, we have devoted this book into three specialized sections: Part 1. In this section we have studied a class of shrinkage estimators for shape parameter beta in failure censored samples from two-parameter Weibull distribution when some 'apriori' or guessed interval containing the parameter beta is available in addition to sample information and analyses their properties. Some estimators …

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The Fusion And Integration Of Virtual Sensors, Thomas F. Litant Jan 2002

The Fusion And Integration Of Virtual Sensors, Thomas F. Litant

Dissertations, Theses, and Masters Projects

There are numerous sensors from which to choose when designing a mobile robot: ultrasonic, infrared, radar, or laser range finders, video, collision detectors, or beacon based systems such as the Global Positioning System. In order to meet the need for reliability, accuracy, and fault tolerance, mobile robot designers often place multiple sensors on the same platform, or combine sensor data from multiple platforms. The combination of the data from multiple sensors to improve reliability, accuracy, and fault tolerance is termed Sensor Fusion.;The types of robotic sensors are as varied as the properties of the environment that need to be sensed. …

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Preparation And Characterization Of Polyimide/Organoclay Nanocomposites, Donavon Mark Delozier Jan 2002

Preparation And Characterization Of Polyimide/Organoclay Nanocomposites, Donavon Mark Delozier

Dissertations, Theses, and Masters Projects

The purpose of this research was to prepare nanocomposite materials comprised of exfoliated clay particles in a polyimide matrix. Poly(amide acid)/organoclay solutions and polyimide/organoclay films were prepared and the clay dispersion was characterized by visual inspection, XRD, and TEM. Mechanical measurements and certain thermal characterization measurements were also obtained. The research began by attempting to repeat the procedures set forth in the literature. Most of the polyimide/organoclay nanocomposites were being prepared by mixing prepared poly(amide acid) solutions with organoclay solutions. This simple mixing technology was used in the preparation of various polyimide/organoclay hybrid formulations. In-situ polymerization, which involved performing the …

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Sediment Transport In Wind-Exposed Shallow, Vegetated Aquatic Systems, Allen Michael Teeter Jan 2002

Sediment Transport In Wind-Exposed Shallow, Vegetated Aquatic Systems, Allen Michael Teeter

LSU Doctoral Dissertations

Ecosystems with submersed vegetation are relatively shallow, physically stable and of moderate hydrodynamic energy. Submersed vegetation affect hydrodynamic friction for currents and waves resulting in increased overall frictional loss. Seagrasses shelter the sediment bed and reduce wind-wave resuspension. Bed sheltering factors were estimated from previous flume data on Laguna Madre seagrass species. Data from Laguna Madre indicate that total suspended material levels for bare areas are about an order of magnitude higher than some areas with submersed vegetation. Waves in Laguna Madre at depths less than 2 m were found to be smaller than those expected for the same non-dimensional …

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Oyster Reef Restoration In Virginia: Broodstock Addition & Nutrient Exchanges, Laurie Ann Sorabella Jan 2002

Oyster Reef Restoration In Virginia: Broodstock Addition & Nutrient Exchanges, Laurie Ann Sorabella

Dissertations, Theses, and Masters Projects

No abstract provided.

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A Monotone Follower Control Problem With A Nonconvex Functional And Some Related Problems, Jamiiru Luttamaguzi Jan 2002

A Monotone Follower Control Problem With A Nonconvex Functional And Some Related Problems, Jamiiru Luttamaguzi

LSU Doctoral Dissertations

A generalized one-dimensional monotone follower control problem with a nonconvex functional is considered. The controls are assumed to be nonnegative progressively measurable processes. The verification theorem for this problem is presented. A specific monotone follower control problem with a nonconvex functional is then considered in which the diffusion term is constant. The optimal control for this problem, which is explicitly given, can be viewed as tracking a standard Wiener process by a non anticipating process starting at 0. For some parameters values, the value function for this monotone follower control problem is shown to be C2 and for other …

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Glass Transition Behavior Of Thin Poly(Methyl Methacrylate) Films On Silica, Moses T. Kabomo Jan 2002

Glass Transition Behavior Of Thin Poly(Methyl Methacrylate) Films On Silica, Moses T. Kabomo

Masters Theses

"Modulated Differential Scanning Calorimetry (MDSC) was used to study the glass transition behavior of poly(methyl methacrylate) (PMMA) adsorbed onto silica substrates from toluene. Untreated fumed amorphous silica and silica treated with hexamethyldisilazane were used for the adsorption to probe the effect of polymer- substrate interactions. To test the effect of molecular weight on the Tg of adsorbed polymers, low polydispersity PMMA samples of varying molecular weights were used. The results revealed a broadening of the glass transition towards high temperatures. The observed increase in the glass transition breadth varied with adsorbed amount and the type of silica used for …

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Stratigraphy And Diagenesis Of The Paleoproterozoic Bushy Park Zinc-Lead Deposit, South Africa, William Daniel Baugaard Jan 2002

Stratigraphy And Diagenesis Of The Paleoproterozoic Bushy Park Zinc-Lead Deposit, South Africa, William Daniel Baugaard

Masters Theses

“The Bushy Park zinc-lead deposit is located in the Northern Cape Province, South Africa. The sulfides are hosted by karst-related breccias that were formed in carbonate shelf deposits of the Neoarchean (2.55 Ga) Campbellrand Subgroup. These rocks are dolomitized completely and silicified partially but have not undergone major metamorphism and thus display remarkable preservation of depositional fabrics. The stratigraphic interval includes the Papkuil and Klippan Formations (> 210 m), a sequence of cyclic microbial laminates interbedded with domed and columnar stromatolites. The Klippan is distinguished from other formations b intense silicification and brecciation. These strata are overlain by the Kogelbeen …

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Anatomy Of A Coupling Query In A Web Warehouse, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim Jan 2002

Anatomy Of A Coupling Query In A Web Warehouse, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

To populate a data warehouse specifically designed for Web data, i.e. web warehouse, it is imperative to harness relevant documents from the Web. In this paper, we describe a query mechanism called coupling query to glean relevant Web data in the context of our web warehousing system called Warehouse Of Web Data (WHOWEDA). Coupling query may be used for querying both HTML and XML documents. Some of the important features of our query mechanism are ability to query metadata, content, internal and external (hyperlink) structure of Web documents based on partial knowledge, ability to express constraints on tag attributes and …

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Enhancing Profiles For Anomaly Detection Using Time Granularities, Yingjiu Li, Ningning Wu, X. Sean Wang, Sushil Jajodia Jan 2002

Enhancing Profiles For Anomaly Detection Using Time Granularities, Yingjiu Li, Ningning Wu, X. Sean Wang, Sushil Jajodia

Research Collection School Of Computing and Information Systems

Recently, association rules have been used to generate profiles of normal behavior for anomaly detection. However, the time factor (especially in terms of multiple time granularities) has not been utilized extensively in generation of these profiles. In reality, user behavior during different time intervals may be very different. For example, the normal number and duration of FTP connections may vary from working hours to midnight, from business day to weekend or holiday. Furthermore, these variations may depend on the day of the month or the week. This paper proposes to build profiles using temporal association rules in terms of multiple …

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Mosquito Population Dynamics During The Establishment Phase Of A Constructed Desert Wetland, April Newman Jan 2002

Mosquito Population Dynamics During The Establishment Phase Of A Constructed Desert Wetland, April Newman

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Nature Preserve at the Clark County Wetlands Park is a constructed wetland that has the potential to produce new mosquito habitat. This thesis evaluates the potential for the development of a mosquito problem at the newly constructed wetland system by assessing the population dynamics of mosquitoes within the Nature Preserve. Based on data collected from May 2001 through January 2002, I describe fluctuations in mosquito genus and relative abundance during the first summer through winter period of wetland development.

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Algal Blooms Reduce The Uptake Of Toxic Methylmercury In Freshwater Food Webs, Paul C. Pickhardt, Carol L. Folt, Celia Y. Chen, Bjoern Klaue, Joel D. Blum Jan 2002

Algal Blooms Reduce The Uptake Of Toxic Methylmercury In Freshwater Food Webs, Paul C. Pickhardt, Carol L. Folt, Celia Y. Chen, Bjoern Klaue, Joel D. Blum

Dartmouth Scholarship

Mercury accumulation in fish is a global public health concern, because fish are the primary source of toxic methylmercury to humans. Fish from all lakes do not pose the same level of risk to consumers. One of the most intriguing patterns is that potentially dangerous mercury concentrations can be found in fish from clear, oligotrophic lakes whereas fish from greener, eutrophic lakes often carry less mercury. In this study, we experimentally tested the hypothesis that increasing algal biomass reduces mercury accumulation at higher trophic levels through the dilution of mercury in consumed algal cells. Under bloom dilution, as algal biomass …

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The Effect Of Surface Curvature On Wound Healing In Bone, J. A. Adam Jan 2002

The Effect Of Surface Curvature On Wound Healing In Bone, J. A. Adam

Mathematics & Statistics Faculty Publications

The time-independent nonhomogeneous diffusion equation is solved for the equilibrium distribution of wound-induced growth factor over a hemispherical surface. The growth factor is produced at the inner edge of a circular wound and stimulates healing in regions where the concentration exceeds a certain threshold value. An implicit analytic criterion is derived for complete healing of the wound. (C) 2001 Elsevier Science Ltd. All rights reserved.

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Advances In Space Radiation Shielding Codes, John W. Wilson, Ram K. Tripathi, Garry D. Qualls, Francis A. Cucinotta, Richard E. Prael, John W. Norbury, John H. Heinbockel, John Tweed, Giovanni De Angelis Jan 2002

Advances In Space Radiation Shielding Codes, John W. Wilson, Ram K. Tripathi, Garry D. Qualls, Francis A. Cucinotta, Richard E. Prael, John W. Norbury, John H. Heinbockel, John Tweed, Giovanni De Angelis

Mathematics & Statistics Faculty Publications

Early space radiation shield code development relied on Monte Carlo methods and made important contributions to the space program. Monte Carlo methods have resorted to restricted one-dimensional problems leading to imperfect representation of appropriate boundary conditions. Even so, intensive computational requirements resulted and shield evaluation was made near the end of the design process. Resolving shielding issues usually had a negative impact on the design. Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from …

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A Partial Order On The Orthogonal Group, Colum Watt, Thomas Brady Jan 2002

A Partial Order On The Orthogonal Group, Colum Watt, Thomas Brady

Articles

We define a natural partial order on the orthogonal group and completely describe the intervals in this partial order. The main technical ingredient is that an orthogonal transformation induces a unique orthogonal transformation on each subspace of the orthogonal complement of its fixed subspace.

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Modeling The Biogeochemical Cycle Of Selenium In The San Francisco Bay, Shannon L. Meseck Jan 2002

Modeling The Biogeochemical Cycle Of Selenium In The San Francisco Bay, Shannon L. Meseck

OES Theses and Dissertations

Due to recent concerns about selenium toxicity in the San Francisco Bay and the roles of refinery and San Joaquin River inputs on the selenium cycle, the model ECoS 3 (distributed from Plymouth Marine Laboratory, United Kingdom) was modified to simulate the biogeochemical cycle of selenium in the Northern Reach. The model is designed to simulate salinity, total suspended material, phytoplankton concentrations, dissolved selenium and its speciation (selenite, selenate, and organic selenide), and particulate selenium and its speciation (selenite + selenate, elemental selenium, and organic selenide). Actual data from 1999 were used to calibrate the model, while data from other …

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Snowmobiling In Maine: Past Successes, Future Challenges, David Vail Jan 2002

Snowmobiling In Maine: Past Successes, Future Challenges, David Vail

Maine Policy Review

With one snowmobile registration for every 15 residents, Maine may well have the most snowmobiles per capita of any U.S. state. Moreover, the state’s 12,000-mile network of groomed trails and its 2,500-mile Interconnected Trail System make it a major winter tourist attraction. Still, as David Vail points out—and as the number of snowmobile-related deaths confirms—such progress has not come without costs and conflict. Although Vail argues the benefits outweigh the costs, he suggests Maine should act now to alleviate the conflicts related to congestion, over use of the state’s major trails, noise and air pollution, and free riding by non-dues-paying …

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A Comparison Of Evolutionary And Coevolutionary Search, Ludo Pagie, Melanie Mitchell Jan 2002

A Comparison Of Evolutionary And Coevolutionary Search, Ludo Pagie, Melanie Mitchell

Computer Science Faculty Publications and Presentations

Previous work on coevolutionary search has demonstrated both successful and unsuccessful applications. As a step in explaining what factors lead to success or failure, we present a comparative study of an evolutionary and a coevolutionary search model. In the latter model, strategies for solving a problem coevolve with training cases. We find that the coevolutionary model has a relatively large efficacy: 86 out of 100 (86%) of the simulations produce high quality strategies. In contrast, the evolutionary model has a very low efficacy: a high quality strategy is found in only two out of 100 runs (2%). We show that …

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Thread Transparency In Information Flow Middleware, Rainer Koster, Andrew P. Black, Jie Huang, Jonathan Walpole, Calton Pu Jan 2002

Thread Transparency In Information Flow Middleware, Rainer Koster, Andrew P. Black, Jie Huang, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

Existing middleware is based on control-flow centric interaction models such as remote method invocations, poorly matching the structure of applications that process continuous information flows. Difficulties cultiesin building this kind of application on conventional platforms include flow-specific concurrency and timing requirements, necessitating explicit management of threads, synchronization, and timing by the application programmer. We propose Infopipes as a high-level abstraction for information flows, and we are developing a middleware framework that supports this abstraction. Infopipes transparently handle complexities associated with control flow and multi-threading. From high-level configuration descriptions the platform determines what parts of a pipeline require separate threads or …

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Investigating Nitrogen Pollution In The Canoochee River, Evans County, Georgia, Chandra Marie Pitt Brown Jan 2002

Investigating Nitrogen Pollution In The Canoochee River, Evans County, Georgia, Chandra Marie Pitt Brown

Legacy ETDs

No abstract provided.

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Supplemental Data: Effects Of Physical Mixing On The Attenuation Of Polycyclic Aromatic Hydrocarbons In Estuarine Sediments., Krisa M. Arzayus, Rebecca M. Dickhut, Elizabeth A. Canuel Jan 2002

Supplemental Data: Effects Of Physical Mixing On The Attenuation Of Polycyclic Aromatic Hydrocarbons In Estuarine Sediments., Krisa M. Arzayus, Rebecca M. Dickhut, Elizabeth A. Canuel

Reports

To examine the role of physical disturbance on the long-term preservation of polycyclic aromatic hydrocarbons (PAHs) in sediments, cores were collected from two sites removed from point sources of PAHs and representing contrasting seabed mixing regimes. Although SPAH concentrations in sediments over the past 50 years were not significantly different between the two sites, several PAH isomer ratios were significantly different (p

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Accomack County Shoreline Situation Report, Marcia Berman, Harry Berquist, Sharon Dewing, J. B. Glover, Carl Hershner, Tamia Rudnicky, Daniel E. Schatt Jan 2002

Accomack County Shoreline Situation Report, Marcia Berman, Harry Berquist, Sharon Dewing, J. B. Glover, Carl Hershner, Tamia Rudnicky, Daniel E. Schatt

Reports

No abstract provided.

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Cpl: A Language For Real-Time Distributed Object Programming, Erhan Saridoğan, Nadi̇a Erdoğan Jan 2002

Cpl: A Language For Real-Time Distributed Object Programming, Erhan Saridoğan, Nadi̇a Erdoğan

Turkish Journal of Electrical Engineering and Computer Sciences

As processing and time requirements of computer systems increase over the borders of single processor architectures, it is becoming more and more attractive to use distributed computing with additional real-time capabilities. In several cases, traditional programming languages have become insufficient to build distributed systems easily, especially when real-time issues and basic software quality factors are concerned. In this paper, a concurrent, object-oriented, distributed real-time programming language, CPL, with a supportive run-time system, namely the CORD-RTS, is introduced and new language features are described. The new language provides an efficient solution for command and control systems by embedding distribution and real-time …

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