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2003

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Articles 3811 - 3840 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Determination Of Home Techniques For Storing And Conserving Food In The Homes Of Cuambo And La Rinconada In Imbabura Province, 2001-2002, Marisol Caicedo Barrios Jan 2003

Determination Of Home Techniques For Storing And Conserving Food In The Homes Of Cuambo And La Rinconada In Imbabura Province, 2001-2002, Marisol Caicedo Barrios

Theses and Dissertations

In Ecuador, there is a grave socioeconomic nutritional problem, and it is seen clearest in Imbabura province in the communities of Cuambo and La Rinconada. One of the biggest problems is inadequate food, due principally to the poor food storage and conservation habits. Considering this problem, it is necessary to deepen the knowledge of improved traditional techniques for storing and conserving food, through which families can store and manage their product better, controlling and avoiding losses due to insects, rodents, and climate, and guaranteeing conservation of the same. The investigation was oriented to implement alternative, improved storage and conservation technologies …


Self-Aggregates Of Cationic Meso-Tetratolylporphyrins In Aqueous Solutions, Pavel Kubat, Kamil Lang, Kristina Prochazkova, Pavel Anzenbacher Jr. Jan 2003

Self-Aggregates Of Cationic Meso-Tetratolylporphyrins In Aqueous Solutions, Pavel Kubat, Kamil Lang, Kristina Prochazkova, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Aggregation properties of meso-tetratolylporphyrins bearing cationic substituents of a lipophilic nature such as ammonium, pyridinium, phosphonium, sulfonium, and isothiouronium were studied by UV/vis and resonance light scattering spectroscopy. The exciton point-dipole approximation was used to predict the structural alignment of the porphyrin units within the aggregate. The contribution of various types of aggregates depends on the porphyrin substitution, ionic strength, and temperature of aqueous solution of the porphyrin. In general, the preferred structure of an aggregate formed by temperature-induced aggregation is the J-aggregate exhibiting the characteristically narrow, red-shifted Soret band indicating a parallel "side-by-side" arrangement of the porphyrin units. The …


Photoinduced Electron-Transfer Along Alpha-Helical And Coiled-Coil Metallopeptides, Anna Fedorova, Anita Chaudhari, Michael Y. Ogawa Jan 2003

Photoinduced Electron-Transfer Along Alpha-Helical And Coiled-Coil Metallopeptides, Anna Fedorova, Anita Chaudhari, Michael Y. Ogawa

Chemistry Faculty Publications

A peptide-based electron-transfer system has been designed in which the specific positions of redox-active metal complexes appended to either an a-helix, or an a-helical coiled-coil, can be reversed to test the effect of the helix dipole in controlling photoinduced electron-transfer rates. Two 30-residue apopeptides were prepared having the following sequences: (1) Ac-K-(IEALEGK)(ICALEGK)(IEALEHK)-(IEALEGK)-G-amide, and (II) Ac-K-(IEALEGK)(IHALEGK)-(IEALECK)(IEALEGK)-G-amide. Each apopeptide was reacted first with [Ru(bpy)(2)(phen-ClAc)](2+), where bpy = 2,2'-bipyridine and phen-ClAc = 5-chloroacetamido-1,10-phenanthroline, to attach the ruthenium polypyridyl center to the cysteine side-chain of the polypeptide. The isolated products were then reacted with [Ru(NH3)(5)(H2O)](2+) to yield the binuclear electron-transfer metallopeptides ET-I and ET-II. …


On String Topology Of Three Manifolds, Hossein Abbaspour Jan 2003

On String Topology Of Three Manifolds, Hossein Abbaspour

Dissertations, Theses, and Capstone Projects

In this dissertation we establish a connection between some aspects of the string topology of three dimensional manifolds and their topology and geometry using the theory of the prime decomposition and characteristic surfaces.


Investigating The Urban Heat Island Effect With A Collaborative Inquiry Project, Linda Acha George, William G. Becker Jan 2003

Investigating The Urban Heat Island Effect With A Collaborative Inquiry Project, Linda Acha George, William G. Becker

Environmental Science and Management Faculty Publications and Presentations

Modification of the earth's surface through urbanization can have a dramatic impact on local climate. A phenomenon known as the Urban Heat Island (UHI) effect, which is a measure of the near-surface air temperature contrast between urbanized and adjoining rural areas, can be evaluated with readily available instruments. Students in an undergraduate general education science course study this phenomenon in the Portland, Oregon area through a collaborative research project. This inquiry project includes background content and literature review, preliminary studies, development of research questions, experimental design and implementation, data analysis and report writing. This project successfully enables students to collaboratively …


Preliminary Investigations Of Seasonal Changes In The Geochemical Evolution Of The Logdson River, Mammoth Cave, Kentucky, Chris Groves, Darlene M. Anthony, Joe Meiman Jan 2003

Preliminary Investigations Of Seasonal Changes In The Geochemical Evolution Of The Logdson River, Mammoth Cave, Kentucky, Chris Groves, Darlene M. Anthony, Joe Meiman

Earth, Environmental, and Atmospheric Sciences Faculty Publications

Many geochemical studies have been made of karst waters worldwide. Most data that provide the framework for our current understanding of the evolution of karst waters have come from sampling at discrete times and locations, such as springs or wells. Relatively few studies have been made of the geochemical evolution of groundwater as it moves through an open flow system. This paper addresses the seasonal changes in the geochemistry of the Logsdon River conduit as it passes through nearly 10km of the carbonate aquifer of south-central Kentucky . The most important control on the ability of groundwaters to dissolve limestone …


Could Mammoth Cave Be Reduced To A Single Equation?, Chris Groves, Joe Meiman Jan 2003

Could Mammoth Cave Be Reduced To A Single Equation?, Chris Groves, Joe Meiman

Earth, Environmental, and Atmospheric Sciences Faculty Publications

Since the evolution of any cave system is largely deterministic, in theory the processes responsible for this development could be described mathematically. In a practical sense, we will never have such a model to realistically describe the evolution of the Mammoth Cave System in detail. However, the search itself can provide a framework within which to understand what processes areimportant. This can guide the design of rate process studies that would eventually be coupled to provide a comprehensive understanding of the cave's evolution. Data gaps, as well, are identified during this process. The geometry of a cave system depends on …


The Crest, Winter 2003, Virginia Institute Of Marine Science Jan 2003

The Crest, Winter 2003, Virginia Institute Of Marine Science

Reports

Table of Contents:

  • VIMS research helps protect Navy ships from mines
  • Moore monitors water quality and seagrasses
  • Orth studies seed predators
  • Researchers see Bay in a grain of sand
  • VIMS reviews VSC proposal
  • NAS studies C. ariakensis
  • Steinberg conducts zooplankton census
  • Russian taxonomist visits
  • Schaffner wins award
  • VIMS work on hard clams pays off
  • VIMS leads Antarctic LTER Program
  • VIMS helps manage shellfish waters


St. Mary’S County, Maryland Shoreline Situation Report - Methods And Guidelines, Alayde Barbosa, Marcia Berman, Harry Berquist, Sharon Dewing, Carl Hershner, Tamia Rudnicky, Daniel E. Schatt, David Weiss, Helen Woods Jan 2003

St. Mary’S County, Maryland Shoreline Situation Report - Methods And Guidelines, Alayde Barbosa, Marcia Berman, Harry Berquist, Sharon Dewing, Carl Hershner, Tamia Rudnicky, Daniel E. Schatt, David Weiss, Helen Woods

Reports

No abstract provided.


Ionic Strength Effects On Hexadecane Contact Angles On A Gold-Coated Glass Surface In Ionic Surfactant Solutions, A. Davis, Samuel Morton, R. Counce, D. Depaoli, M. Hu Dec 2002

Ionic Strength Effects On Hexadecane Contact Angles On A Gold-Coated Glass Surface In Ionic Surfactant Solutions, A. Davis, Samuel Morton, R. Counce, D. Depaoli, M. Hu

Samuel A Morton

No abstract provided.


An Insider's View Of Cmm(R) Level 5, Robert Yacobellis Dec 2002

An Insider's View Of Cmm(R) Level 5, Robert Yacobellis

Robert H Yacobellis

No abstract provided.


Mockup-Driven Fast-Prototyping Methodology For Web Application Development, Jia Zhang, Jen-Yao Chung Dec 2002

Mockup-Driven Fast-Prototyping Methodology For Web Application Development, Jia Zhang, Jen-Yao Chung

Jia Zhang

No abstract provided.


Inverting For Heterogeneous Slip On Three-Dimensional Fault Systems; A First Step Toward Understanding Fault Mechanics, Phillip Resor, D Pollard, F Maerten Dec 2002

Inverting For Heterogeneous Slip On Three-Dimensional Fault Systems; A First Step Toward Understanding Fault Mechanics, Phillip Resor, D Pollard, F Maerten

Phillip G Resor

Many studies of earthquake triggering and fault interaction have relied on highly-idealized fault geometries and slip distributions. Geological and geophysical observations, however, reveal that faults typically are not single planar surfaces with uniform slip bounded by rectangular tiplines, but are composed of multiple curved surfaces with curved tiplines and heterogeneous slip distributions. The segments typically are organized into echelon, conjugate, and intersecting patterns. The discontinuities, bends, intersections, and slip heterogeneities generate stress concentrations that may promote or inhibit slip on nearby faults and thus play an important role in the mechanics of fault systems. It is therefore important to incorporate …


Bayesian Modelling And Forecasting Of Intra-Day Electricity Load, Remy Cottet, Michael Smith Dec 2002

Bayesian Modelling And Forecasting Of Intra-Day Electricity Load, Remy Cottet, Michael Smith

Michael Stanley Smith

With the advent of wholesale electricity markets there has been renewed focus on intra-day electricity load forecasting. This paper employs a multi-equation regression model with a diagonal first order stationary vector autoregresson (VAR) for modeling and forecasting intra-day electricity load. The correlation structure of the disturbances to the VAR and the appropriate subset of regressors are explored using Bayesian model selection methodology. The full spectrum of finite sample inference is obtained using a Bayesian Markov chain Monte Carlo sampling scheme. This includes the predictive distribution of load and the distribution of the time and level of daily peak load, something …


Geochemistry Of Kauai Shield-Stage Lavas: Implications For The Chemical Evolution Of The Hawaiian Plume, Scott Bogue, S. Mukhopadhyay, J.C. Lassiter, K.A. Farley Dec 2002

Geochemistry Of Kauai Shield-Stage Lavas: Implications For The Chemical Evolution Of The Hawaiian Plume, Scott Bogue, S. Mukhopadhyay, J.C. Lassiter, K.A. Farley

Scott Bogue

We measured He, Sr, Nd, Pb, and Os isotope ratios and major and trace element concentrations in stratigraphically and paleomagnetically controlled shield-stage lavas from Kauai, Hawaii. The range of 3He/4He ratios (17–28 RA) from Kauai is similar to that reported from Loihi and thus challenges the prevailing notion that high 3He/4He ratios are restricted to the preshield stage of Hawaiian magmatism. 3He/4He ratios vary erratically with stratigraphic position, and chronostratigraphic control from paleomagnetic data indicates very rapid changes in the 3He/4He ratios (up to 8 RA in ∼102 years). These variations in helium isotopic ratios are correlated with variations in …


Working Across Cultures, John Hooker Dec 2002

Working Across Cultures, John Hooker

John Hooker

No abstract provided.


Graphs Of Essentially Equivalent Lattice Paths, Lara Pudwell, Marjorie Brewer, Adam Hughes Dec 2002

Graphs Of Essentially Equivalent Lattice Paths, Lara Pudwell, Marjorie Brewer, Adam Hughes

Lara K. Pudwell

No abstract provided.


Classifying Instantaneous Cognitive States From Fmri Data, Tom Mitchell, Rebecca Hutchinson, Marcel Just, Radu Niculescu, Francisco Pereira, Xuerui Wang Dec 2002

Classifying Instantaneous Cognitive States From Fmri Data, Tom Mitchell, Rebecca Hutchinson, Marcel Just, Radu Niculescu, Francisco Pereira, Xuerui Wang

Marcel Adam Just

No abstract provided.


On Abel-Gontscharoff-Gould's Polynomials, Tian-Xiao He, Leetsch Hsu, Peter Shiue Dec 2002

On Abel-Gontscharoff-Gould's Polynomials, Tian-Xiao He, Leetsch Hsu, Peter Shiue

Tian-Xiao He

In this paper a connective study of Gould’s annihilation coefficients and Abel-Gontscharoff polynomials is presented. It is shown that Gould’s annihilation coefficients and Abel-Gontscharoff polynomials are actually equivalent to each other under certain linear substitutions for the variables. Moreover, a pair of related expansion formulas involving Gontscharoff’s remainder and a new form of it are demonstrated, and also illustrated with several examples.


Ultrafast Two-Photon Free Induction Decay, D. Keusters, Peifang Tian, W. Warren Dec 2002

Ultrafast Two-Photon Free Induction Decay, D. Keusters, Peifang Tian, W. Warren

Peifang Tian

No abstract provided.


Space Ship Earth – Clinic In Forest, Nat Quansah Dec 2002

Space Ship Earth – Clinic In Forest, Nat Quansah

Nat Quansah

No abstract provided.


A Comparison Of Semi-Analytical And Numerical Solutions For The Microwave Heating Of A Lossy Material In A Three-Dimensional Waveguide, Prof. Tim Marchant Dec 2002

A Comparison Of Semi-Analytical And Numerical Solutions For The Microwave Heating Of A Lossy Material In A Three-Dimensional Waveguide, Prof. Tim Marchant

Tim Marchant

The microwave heating of a three-dimensional block in an infinitely long rectangular waveguide propagating the TE10 mode is considered. The electrical conductivity (the dielectric loss) is assumed to be a function of temperature, and modelled by the Arrhenius law. A coupled set of equations is obtained that describes the electromagnetic fields and the temperature distribution in the block. The numerical solutions of this problem are obtained by two methods, the well known FD-TD scheme and a frequency domain method which makes the further assumption that a single TE10 mode exists in the waveguide and material. The results show that an …


No Frictional Heat Along The San Gabriel Fault, California: Evidence From Fission-Track Thermochronology, M.A. D’Alessio, Ann Blythe, R Bu¨Rgmann Dec 2002

No Frictional Heat Along The San Gabriel Fault, California: Evidence From Fission-Track Thermochronology, M.A. D’Alessio, Ann Blythe, R Bu¨Rgmann

Ann Blythe

Large earthquakes generate frictional heat, and the magnitude of heating is related to the slip magnitude, the applied effective normal stress, and the frictional strength of the fault. We looked for evidence of this heating in apatite fission-track age and track-length distributions of samples from adjacent to and within the San Gabriel fault zone in southern California. The fault is thought to be an abandoned major trace of the San Andreas fault system active from 13 to 4 Ma and has since been exhumed from depths of 2–5 km. At our sample locality, as much as 40 km of total …


Boundary-Type Quadrature And Boundary Element Method, Tian-Xiao He Dec 2002

Boundary-Type Quadrature And Boundary Element Method, Tian-Xiao He

Tian-Xiao He

In this paper, we apply a boundary-type quadrature technique to derive a type of boundary element scheme, which is used to solve the boundary-value problems of partial differential equations.Numerical examples for solving the exterior boundary-value problem of Helmholtz equation by using the spline approximation and the spline wavelet approximation are given.


Committee On Climate Change And Sustainable Development: 2002 Annual Report, John Dernbach Dec 2002

Committee On Climate Change And Sustainable Development: 2002 Annual Report, John Dernbach

John C. Dernbach

No abstract provided.


Micro Thermoelectric Cooler Fabrication: Growth And Characterization Of Patterned Sb2te3 And Bi2te3 Films ., Luciana Da Silva, M. Kaviany, A. Dehennis, Jeffrey Dyck Dec 2002

Micro Thermoelectric Cooler Fabrication: Growth And Characterization Of Patterned Sb2te3 And Bi2te3 Films ., Luciana Da Silva, M. Kaviany, A. Dehennis, Jeffrey Dyck

Jeffrey Dyck

A column-type micro thermoelectric cooler is being fabricated using p-type Sb2Te3 and n-type Bi2Te3 films (approximately 4 μm thick). The films are grown by thermal co-evaporation and patterned on Cr/Au/Ti/Pt (hot) connectors, which are deposited onto a silicon dioxide coated wafer. The column height is limited by control of the Te deposition rate. Although a high substrate temperature during thermoelectric film deposition is desired, it has been limited by the degradation of the photoresist used for patterning. The measured Seebeck coefficient and electrical resistivity of the thermoelectric films are reported, and preliminary results show that excess tellurium increases the Seebeck …


Analytical Upstream Collocation Solution Of A Forced Steady-State Convection-Diffusion Equation, Stephen Brill Dec 2002

Analytical Upstream Collocation Solution Of A Forced Steady-State Convection-Diffusion Equation, Stephen Brill

Stephen H. Brill

We give herein formulas for the solution of the Hermite collocation discretization of a nonhomogeneous steady-state convection-diffusion equation in one spatial dimension and with constant coefficients, defined on a uniform mesh, with Dirichlet boundary conditions. The accuracy of the method is enhanced by employing "upsteam weighting" of the convective term in an optimal way. We discuss also the issue of where to optimally sample the forcing function. Computational examples illustrate the efficacy of the optimal upstream weighting technique combined with optimal sampling of the forcing function.


Oil Droplet Detachment From Metal Surfaces As Affected By And Applied Potential, A. Rowe, A. Davis, R. Counce, Samuel Morton, D. Depaoli, M. Hu Dec 2002

Oil Droplet Detachment From Metal Surfaces As Affected By And Applied Potential, A. Rowe, A. Davis, R. Counce, Samuel Morton, D. Depaoli, M. Hu

Samuel A Morton

No abstract provided.


A Solvent-Free Claisen Condensation Reaction For The Organic Laboratory, John Esteb, Matthew Stockton Dec 2002

A Solvent-Free Claisen Condensation Reaction For The Organic Laboratory, John Esteb, Matthew Stockton

John Esteb

An experiment involving the Claisen condensation reaction for a first-year organic chemistry laboratory is presented. Claisen condensations are routinely covered in organic textbooks but owing to the long reaction times required to reach equilibrium in solution they are seldom explored in the undergraduate teaching laboratory. In this experiment, potassium tert-butoxide and ethyl phenylacetate are heated to 100 °C for 30 minutes under solvent-free conditions to produce 2,4-diphenyl acetoacetate in 80% yield. The solvent-free nature of this procedure greatly reduces the quantity of waste generated by students relative to typical carbonyl condensation experiments.

Note:Link is to the article in a …


Rating And Ranking Versus Compliance Analysis; Defuzzification Techniques For Conceptual Design Evaluation, Caroline Lubert, D. Verma Dec 2002

Rating And Ranking Versus Compliance Analysis; Defuzzification Techniques For Conceptual Design Evaluation, Caroline Lubert, D. Verma

Caroline P Lubert

No abstract provided.