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1996

Modeling

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Nfma In Relation To Stewardship, Science, Community And Culture: Some Points Of View From The Alaska Region, Phil Janik, Neil Hagadorn, Rai Behnert Sep 1996

Nfma In Relation To Stewardship, Science, Community And Culture: Some Points Of View From The Alaska Region, Phil Janik, Neil Hagadorn, Rai Behnert

The National Forest Management Act in a Changing Society, 1976-1996: How Well Has It Worked in the Past 20 Years?: Will It Work in the 21st Century? (September 16-18)

10 pages.


Modeling Transport Of Colloid-Bound Herbicides And Heavy Metals To Groundwater, Anastasios D. Karathanasis, R. E. Phillips, A. K. Seta Jun 1996

Modeling Transport Of Colloid-Bound Herbicides And Heavy Metals To Groundwater, Anastasios D. Karathanasis, R. E. Phillips, A. K. Seta

KWRRI Research Reports

Recent studies have suggested that contaminant transport to groundwater may be enhanced by association with colloidal particles. This study evaluated the role of water dispersible colloids with diverse mineralogical composition in co-transporting selected herbicides and heavy metals through intact soil columns. Colloid recovery in the eluents ranged from 45-90% for the herbicides and 10-60% for the heavy metals. The presence of colloids enhanced the transport of atrazine by 2-18%, and metolachlor by 8-30%. The corresponding increase for Cu and Zn was 2-150 and 5-30 times, respectively. For Pb, there was essentially no elution in the absence of colloids, suggesting nearly …


Modeling The Lower Chesapeake Bay Littoral Zone & Fringing Wetlands: Modeling The Lower Chesapeake Bay Littoral Zone & Fringing Wetlands: Ecosystem Processes And Habitat Linkages.Ii. Model Sensitivity Analysis, Validation, And Estimates Of Ecosystem Processes, Christopher P. Buzzelli, Richard L. Wetzel Jun 1996

Modeling The Lower Chesapeake Bay Littoral Zone & Fringing Wetlands: Modeling The Lower Chesapeake Bay Littoral Zone & Fringing Wetlands: Ecosystem Processes And Habitat Linkages.Ii. Model Sensitivity Analysis, Validation, And Estimates Of Ecosystem Processes, Christopher P. Buzzelli, Richard L. Wetzel

Reports

No abstract provided.


A Direct, Approximate Solution To The Modified Green-Ampt Infiltration Equation, Puneet Srivastava, Thomas A. Costello, Dwayne R. Edwards Jan 1996

A Direct, Approximate Solution To The Modified Green-Ampt Infiltration Equation, Puneet Srivastava, Thomas A. Costello, Dwayne R. Edwards

Biosystems and Agricultural Engineering Faculty Publications

Accurately predicting the rainfall-runoff process is of vital importance for water quality models as well as for correct design of various types of hydraulic structures. This article presents a method of describing the cumulative infiltration process as an explicit function of time using an approximation to the modified Green-Ampt equation given by Mein and Larson (1971). The resulting equation is helpful in predicting cumulative infiltration and therefore infiltration capacity for computer simulation models. The proposed method takes about 50% less time than the usual iterative technique for the same degree of accuracy. The maximum error due to approximation was 1% …


Application Of Simplified Phosphorus Transport Models To Pasture Fields In Northwest Arkansas, Dwayne R. Edwards, C. T. Haan, Andrew N. Sharpley, John F. Murdoch, Tommy C. Daniel, Philip A. Moore Jr. Jan 1996

Application Of Simplified Phosphorus Transport Models To Pasture Fields In Northwest Arkansas, Dwayne R. Edwards, C. T. Haan, Andrew N. Sharpley, John F. Murdoch, Tommy C. Daniel, Philip A. Moore Jr.

Biosystems and Agricultural Engineering Faculty Publications

Runoff transport of phosphorus (P) is often predicted from simple equations with parameters determined from data applicable primarily to row-cropped and fallow cover conditions. The applicability, accuracy, and precision of such P transport prediction equations under pasture situations are less well defined. The objectives of this study were to determine parameters of simplified runoff P transport equations for pasture fields and to assess the accuracy and precision of the equations. Runoff, sediment yield, soluble P transport, and particulate P transport data were collected from four pasture fields in northwestern Arkansas. Runoff event enrichment ratios and extraction coefficients were computed, and …


Modeling The Yule-Nielsen Halftone Effect, Jonathan Arney, Charles Arney, Peter Engeldrum Jan 1996

Modeling The Yule-Nielsen Halftone Effect, Jonathan Arney, Charles Arney, Peter Engeldrum

Articles

The Yule-Nielsen effect, also called optical dot gain, is a nonlinear relationship between the reflectance of a halftone image and the fractional dot area of the halftone dots. Two models of the Yule-Nielsen effect are examined. The first is an empirical model previously described in the literature, and the second is an a priori model derived for an idealized halftone line system in one spatial dimension. Both are shown to model halftone behavior well. By combining the two models we derive that a semiempirical function establishes a simple connection between the magnitude of the Yule-Nielsen effect and independently measurable scattering …


A Multiphase Mathematical Model Of A Nickel/Hydrogen Cell, Pauline De Vidts Jan 1996

A Multiphase Mathematical Model Of A Nickel/Hydrogen Cell, Pauline De Vidts

Faculty Publications

No abstract provided.


Modeling International Tourism To Israel, Sharon Regev Jan 1996

Modeling International Tourism To Israel, Sharon Regev

UNLV Retrospective Theses & Dissertations

This research is based on a survey conducted by the Israeli Ministry of Tourism. Using econometric methods that allow inferences from the sample to a population that is not included in the sample, the following model was estimated. The model is based on two simultaneous decisions--the decision to visit Israel and the decision on how much money to spend on the visit. The estimates permit the computations to be made on the likelihood that a certain individual, from the general population, will choose to visit Israel; The main conclusion of this study is that the promotion of Israel in different …


An Object-Oriented Modeling Approach To Build Data Communication Model, Wuqing Xu Jan 1996

An Object-Oriented Modeling Approach To Build Data Communication Model, Wuqing Xu

UNLV Retrospective Theses & Dissertations

The problem of data communications between process units within a telecommunication network based on OSI's standard seven layer Reference Model is addressed. In this thesis, we expose the generic aspect of protocol implementation as an object-oriented conceptual model emphasizing on the dynamic aspects of the objects involved while we explore both aspects, namely, static and dynamic aspects. A data communication model is proposed; Through the development of the conceptual model, we can capture the crucial aspects of network system and omit others. In developing the conceptual model for data communication, we apply object-oriented modeling principles to explore the potential elements …


Design, Modeling, And Characterization Of Fet-Seed Smart Pixel Transceiver Arrays For Optical Backplanes, David V. Plant, Alain Z. Shang, Marcos R. Otazo, David R. Rolston, Brian Robertson, Harvard Scott Hinton Jan 1996

Design, Modeling, And Characterization Of Fet-Seed Smart Pixel Transceiver Arrays For Optical Backplanes, David V. Plant, Alain Z. Shang, Marcos R. Otazo, David R. Rolston, Brian Robertson, Harvard Scott Hinton

Electrical and Computer Engineering Faculty Publications

The design, modeling, and characterization of FET-SEED smart pixel transceiver arrays fabricated for application in optical backplanes are presented. Results of digital and analog measurements on 4×4 transmitter arrays and 4×4 receiver arrays, packaged at the printed circuit-board level, will be presented. In addition, these results will be compared to device and circuit models developed for these optoelectronics. Finally, the description of the successful application of these optoelectronics to interconnect two printed circuit boards will be described.


Dc And Ac Modeling Of Heterostructure Bipolar Transistors (Hbts), Roxana Arvandi Jan 1996

Dc And Ac Modeling Of Heterostructure Bipolar Transistors (Hbts), Roxana Arvandi

UNLV Retrospective Theses & Dissertations

Starting with a homojunction or graded heterojunction bipolar transistor, a complete model for the dc and ac performances of the device is developed based on the Ebers-Moll methodology. The formulation is modified to include the abrupt single HBT, by introducing the effects of the conduction band discontinuity at the base-emitter junction as an energy barrier for electrons flow resulting in transmission and reflection processes. Finally, using the same approach, the formulation is extended to the abrupt double HBT. The collector current as a function of collector-emitter voltage, the collector and base currents as a function of base-emitter voltage, the dc …