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Articles 2281 - 2310 of 2315

Full-Text Articles in Physical Sciences and Mathematics

Analysis Of Shallow Seismicity And Stress Fields In Southeastern Alaska, Hugo Rodriguez Jan 2009

Analysis Of Shallow Seismicity And Stress Fields In Southeastern Alaska, Hugo Rodriguez

Open Access Theses & Dissertations

Southeastern Alaska is dominated by strike-slip motion along the Queen Charlotte-southern Fairweather fault system (QCFS) in the south and transitions to oblique convergent motion partitioned between strike-slip motion along the Denali and northern Fairweather fault systems and thrusting along faults of the St. Elias region. Geologic complications are further increased by the subduction of the Yakutat microplate beneath North America and glacial processes. By studying regional background seismicity we intend to better determine the current state of stress of southeastern Alaska from the Dixon Entrance to Yakutat Bay. Phase data was gathered for over 4000 earthquakes of depths <20 km and magnitude <5 that occurred from 1973-2005 from Alaskan and Canadian databases. We relocated these earthquakes using the Double-Difference joint hypocenter method. Two areas of interest were identified with high concentrations of seismicity after relocation calculations for the entire southeast Alaska region; Glacier Bay through Yakutat (GBY) and the area surrounding Mt. Ogden (MOG). Earthquake locations in GBY are diffuse with some isolated clusters. The MOG subregion is dominated by a large northeast to southwest trending cluster that trends along the Speel River. We used these relocations and first motion data to estimate the stress fields for earthquake clusters that formed. Only a few of the calculated stress tensors were successful in representing the region's overall tectonic signature. We combined the calculated stress information with GPS, magnetic and gravity data in order determine how plate motion is partitioned in this region and to identify other potentially active faults.


An Experimental Study Of The Hydrodynamics Of Multiphase Flow In Fluidized Beds, Gerardo Vargas Jan 2009

An Experimental Study Of The Hydrodynamics Of Multiphase Flow In Fluidized Beds, Gerardo Vargas

Open Access Theses & Dissertations

Fluidized bed reactors have been widely used as a gasifier in coal gasification processes to convert coal into other forms of energy. At this stage, full fluidization is required to attain the best thermochemical reaction within the fluid-solid mixture. This can only be achieved if the fluid is maintained between minimum fluidization and terminal velocities. To better understand the hydrodynamics of multiphase flow, a fluidized bed was designed and constructed to carry out the investigation. Compressed air and 1-mm glass beads were used to determine gas minimum fluidization and terminal velocities at three different particle concentrations. The solids were enclosed …


Estimating Variation In Stiffness And Volume Change Of Clays From Geochemical And Index Properties, Cynthia Roxanna Zuniga Jan 2009

Estimating Variation In Stiffness And Volume Change Of Clays From Geochemical And Index Properties, Cynthia Roxanna Zuniga

Open Access Theses & Dissertations

Clayey soils from six different locations in Texas were analyzed and evaluated with respect to their expansion and shrinkage and change in stiffness associated with moisture content variation. These soils consist of five high plasticity-index (PI) clays (PI greater than 25) and one low-PI clay (PI = 17). The behavior of the clays changes dramatically with moisture content fluctuation, thus causing stiffness and volume changes throughout the year. Total or differential volume movements caused by swell or shrinkage strains of expansive soils and reduction in modulus can exert enough pressure to damage the pavements and cause maintenance problems.

The intent …


Third Grade Students' Challenges And Strategies To Solving Mathematical Word Problems, Elizabeth Bernadette Jan 2009

Third Grade Students' Challenges And Strategies To Solving Mathematical Word Problems, Elizabeth Bernadette

Open Access Theses & Dissertations

This project explores the difficulties and challenges that third grade students face solving mathematical word problems. Three students were asked to be participants and share their knowledge on this topic as well as their work. After extensive interviews it was concluded that the challenges of mathematical word problems include but are not limited to the level of reading comprehension, conceptual understanding of mathematical concepts, and the belief that math is a compilation of computations and unexplainable procedures. The participants provided insight as to what strategies are helpful to students. These strategies include group discussion on problem solving strategies, self-assessment, incorporating …


Temporal And Geochemical Insights Related To Volcanic And Plutonic Activity Within Big Bend National Park, Texas, Daniel Paul Miggins Jan 2009

Temporal And Geochemical Insights Related To Volcanic And Plutonic Activity Within Big Bend National Park, Texas, Daniel Paul Miggins

Open Access Theses & Dissertations

Big Bend National Park located in the southeastern part of the Trans-Pecos Magmatic Province in west Texas contains a diverse suite of volcanic and intrusive rocks. Ongoing geologic mapping, geochronology, and geochemical studies have focused on the timing and geological relationships associated with these volcanic and intrusive rocks. Igneous activity within Big Bend National Park occurred from 46.5 to 22.0 Ma. Precise 40Ar/39Ar and U-Pb zircon geochronology has resolved the timing of this activity into five discrete episodes: 1) eruption and emplacement of both intrusive and volcanic mafic rocks at 46.5 Ma followed by ~42.0 Ma mafic volcanic pulse; 2) …


Help-Based Tutorials, David G. Novick, Oscar D. Andrade, Nathaniel Bean, Edith Elizalde Jan 2008

Help-Based Tutorials, David G. Novick, Oscar D. Andrade, Nathaniel Bean, Edith Elizalde

Departmental Papers (CS)

The consensus of the documentation literature is that users rarely use help, usually preferring to muddle through. To increase use of help, tutorials for novice users could be changed from guided presentations toward using the system’s actual help system. To determine whether this approach would increase users’ use of help when they encountered problems with an application, we developed an alternative, help-based tutorial introduction to Microsoft Publisher. We compared the behaviors of users introduced to Publisher with the help-based tutorial with the behaviors of users who learned from a traditional tutorial. A balanced study of 22 novice users of Publisher …


In-Vivo Delivery Of Dna Vaccines Using Metallo-Lipid Nanoparticles, Clarissa Sara Gomez Jan 2008

In-Vivo Delivery Of Dna Vaccines Using Metallo-Lipid Nanoparticles, Clarissa Sara Gomez

Open Access Theses & Dissertations

There has been a rapidly growing area of research in the design and synthesis of molecules that self-organize in water to form functional nanosystems and due to the high interest in the area metal ligand complexes were tested as drug delivery systems with a Leishmania vaccine. Herein, we present the design, synthesis and functional activity of Cu(II) and Zn(II) complexes that self-assemble in water to form spherical nanoscale structures that exhibit an affinity to bind DNA and deliver it into eukaryotic cells with a high percent efficiency in-vitro. In order to assess the effectiveness of these nanoparticles to deliver DNA …


Adaptive Hp-Fem For Elliptic Problems In 3d On Irregular Meshes, David Andrs Jan 2008

Adaptive Hp-Fem For Elliptic Problems In 3d On Irregular Meshes, David Andrs

Open Access Theses & Dissertations

This work deals with adaptive hp-FEM on irregular meshes. It shows the advantage of completely irregular meshes, using the arbitrary level hanging nodes. The above is demonstrated on a numerical example with distribution of electrical potencial.


A Distributed Reconstruction Of Ekg Signals, Gabriel Cordova Jan 2008

A Distributed Reconstruction Of Ekg Signals, Gabriel Cordova

Open Access Theses & Dissertations

In this Thesis the parallel computing methodology is applied to an algorithm used in the reconstruction of electrocardiographic (EKG) measurements. The reconstructions are being performed to obtain a better understanding of the source and behavior of the electrical activity that generates the EKG measurements. The contribution of this Thesis is to identify and eliminate inefficiencies present in the current reconstruction algorithm. Additionally, this Thesis reduces the computation times of the EKG reconstruction by applying distributed computing through the use of Remote Procedure Calls (RPC). Lastly, it provides an analysis of the speed-up and efficiency of the distribution implemented using parallel …


Screening The Phytoremediation Potential Of Native Plants Growing On Mine Tailings In Arizona, Usa, Md Nazmul Haque Jan 2008

Screening The Phytoremediation Potential Of Native Plants Growing On Mine Tailings In Arizona, Usa, Md Nazmul Haque

Open Access Theses & Dissertations

Mining companies have been playing an important role for the utilization of the Earth's natural resources for the prosperity of human society. However, the mining of resources has generated solid wastes called tailings that have become a serious environmental threat worldwide. Technologies such as soil caping have been used to remediate the problem. Nevertheless, the remediation of mine tailings using conventional technologies is costly and environmentally unpleasant. Since the last few decades, a plant based technology known as phytoremediation has appeared as a promising alternative. Several plant species have demonstrated to have phytoremediation capabilities; though, best results have been obtained …


A Study Of The Interaction Of Thioindigo Dye, With Several Inorganic Host Materials, Alejandra Ramirez Jan 2008

A Study Of The Interaction Of Thioindigo Dye, With Several Inorganic Host Materials, Alejandra Ramirez

Open Access Theses & Dissertations

Maya Blue has been the focus of numerous studies and is believed to be a mixture of palygorskite clay and indigo dye.1,2 Several derivatives of this pigment have been developed with intriguing properties. For instance, the dye thioindigo reacts with the palygorskite clay to exhibit a broad range of colors from red to blue under UV-Vis excitation. Based on FT-Raman and computer simulation, previous work performed in our group could relate indigo and thioindigo interaction to the aluminum sites in the framework. super>3,4

The work performed with other inorganic host materials such as, layer structures and zeolites have …


Study Of Structural And Spectroscopic Properties Of Small Zns Clusters By Dft, Venkata Ramana Chaganti Jan 2008

Study Of Structural And Spectroscopic Properties Of Small Zns Clusters By Dft, Venkata Ramana Chaganti

Open Access Theses & Dissertations

ABSTRACT

The small clusters (aggregates of atoms containing a few tens of atoms) of semiconductors and metals often adopt very different shapes than the fragments of these materials in the bulk phase. Due to their large surface to volume ratio and unsaturated bonds, the small clusters often have properties that are very different from their bulk. Semiconductor clusters are extensively studied for their potential applications in a wide variety of systems from opto-electronic devices to spintronics. The present work is devoted to understanding the structural and electronic properties of small clusters of the zinc sulfide ZnnSn where n = 1 …


Evaluation Of An Image Processing Algorithm For Scene Change Detection, Daniel Flores Jan 2008

Evaluation Of An Image Processing Algorithm For Scene Change Detection, Daniel Flores

Open Access Theses & Dissertations

Despite the efforts to reduce traffic accidents by government entities and automobile manufactures, the numbers of accidents are not considerably reduced. An evaluation of an algorithm based on the fly's eye is done on this research applying its principles to detect scene change on images for printed circuit boards providing initial steps to implement this algorithm on vehicular traffic to keep track of objects moving on the field for collision avoidance purposes. The effectiveness of the algorithm is addressed through a comparison of its performance with that found in experimental data.


Optical And Vibrational Spectroscopic Studies Of Synthetic Maya Pigments As A Function Of, Swati Kumar Jan 2008

Optical And Vibrational Spectroscopic Studies Of Synthetic Maya Pigments As A Function Of, Swati Kumar

Open Access Theses & Dissertations

Pigments developed by the Mayan civilization around 8th century, represent some of the most versatile pigments known to date. Several derivatives of these pigments are popular subjects of current research interest. This is due to the characteristic stability which is provided by a bonding mechanism between the dye and the clay. One such pigment "Maya Blue", a mixture of Indigo and Palygorskite, provides a dramatic background for murals and ceramics throughout Mesoamerica. Several research groups have devoted time and interest in unlocking its particular features.1-3

The work embodied in this Thesis is focused on the synThesis and characterization of three …


A Multi-Tracer Study Of Saltwater Origin, Cross-Formational Flow, And The Geochemical Evolution Of Groundwater In The Southern High Plains Aquifer Along The Western Caprock Escarpment, East-Central New Mexico, Jeff Langman Jan 2008

A Multi-Tracer Study Of Saltwater Origin, Cross-Formational Flow, And The Geochemical Evolution Of Groundwater In The Southern High Plains Aquifer Along The Western Caprock Escarpment, East-Central New Mexico, Jeff Langman

Open Access Theses & Dissertations

Sustainable management of groundwater resources requires sufficient knowledge of the distribution of fresh and saline groundwater and the processes affecting saltwater intrusion that may influence the beneficial use of groundwater. A hydrogeologic investigation that coupled various chemical and isotopic tracers, including 3H/3He, 14C, δD, δ18O, 87Sr/86Sr, and δ11B, with the physical characteristics of the aquifer was conducted to determine source waters, the origin of saltwater and its influence through cross-formational flow, and water-rock interactions in the Southern High Plains aquifer along the Western Caprock Escarpment. Sub-aquifers or local flow systems are present along the Western Caprock Escarpment, and the study …


Usability Inspection Methods After 15 Years Of Research And Practice, Tasha Hollingsed, David G. Novick Oct 2007

Usability Inspection Methods After 15 Years Of Research And Practice, Tasha Hollingsed, David G. Novick

David G. Novick

Usability inspection methods, such as heuristic evaluation, the cognitive walkthrough, formal usability inspections, and the pluralistic usability walkthrough, were introduced fifteen years ago. Since then, these methods, analyses of their comparative effectiveness, and their use have evolved in different ways. In this paper, we track the fortunes of the methods and analyses, looking at which led to use and to further research, and which led to relative methodological dead ends. Heuristic evaluation and the cognitive walkthrough appear to be the most actively used and researched techniques. The pluralistic walkthrough remains a recognized technique, although not the subject of significant further …


Toward A More Accurate View Of When And How People Seek Help With Computer Applications, David G. Novick, Edith Elizalde, Nathaniel Bean Oct 2007

Toward A More Accurate View Of When And How People Seek Help With Computer Applications, David G. Novick, Edith Elizalde, Nathaniel Bean

David G. Novick

Based on 40 interviews and 11 on-site workplace observations of people using computer applications at work, we confirm that use of printed and on-line help is very low and find that providing greater detail of categories solution methods can present a more realistic picture of users’ behaviors. Observed study participants encountered a usability problem on average about once every 75 minutes and typically spent about a minute looking for a solution. Participants consumed much more time when they were unaware of a direct way of doing something and instead used less effective methods. Comparison of results from different data-collection methods …


A Computational Model Of Culture-Specific Conversational Behavior, Dusan Jan, David Herrera, Bilyana Martinovski, David G. Novick, David Traum Sep 2007

A Computational Model Of Culture-Specific Conversational Behavior, Dusan Jan, David Herrera, Bilyana Martinovski, David G. Novick, David Traum

David G. Novick

This paper presents a model for simulating cultural differences in the conversational behavior of virtual agents. The model provides parameters for differences in proxemics, gaze and overlap in turn taking.We present a review of literature on these factors and show results of a study where native speakers of Nrth American English, Mexican Spanish and Arabic were asked to rate the realism of the simulations generated based on different cultural parameters with respect to their culture.


A Novel Class Of Metal-Directed Supramolecular Dna-Delivery Systems, Juan C. Noveron Jan 2007

A Novel Class Of Metal-Directed Supramolecular Dna-Delivery Systems, Juan C. Noveron

Juan C N

No abstract provided.


Single-Crystal To Single-Crystal Phase Transitions Of Bis(N-Phenylisonicotinamide)Silver(I) Nitrate Reveal Cooperativity Properties In Porous Molecular Materials, Juan C. Noveron Jan 2007

Single-Crystal To Single-Crystal Phase Transitions Of Bis(N-Phenylisonicotinamide)Silver(I) Nitrate Reveal Cooperativity Properties In Porous Molecular Materials, Juan C. Noveron

Juan C N

No abstract provided.


Integrated Geophysical Data Processing And Interpretation Of Crustal Structure In Ethiopia With Emphasis On The Ogaden Basin And Adjacent Areas, Ketsela Tadesse Jan 2007

Integrated Geophysical Data Processing And Interpretation Of Crustal Structure In Ethiopia With Emphasis On The Ogaden Basin And Adjacent Areas, Ketsela Tadesse

Open Access Theses & Dissertations

The combined effects of magmatism and stretching due to asthenosphere upwelling modifies the crustal structure of the Earth as seen in the Ethiopian rift and adjacent areas. The Ethiopian rift provides unique opportunities to understand the nature of rifted crust and the intensity of its modification by magmatic processes. I used geological and geophysical data to conduct an integrated study in and around the Ethiopian rift including the northern Kenyan rift and the northern part of the Kenyan dome. New gravity, controlled source seismic, and teleseismic data from the EAGLE (Ethiopia-Afar Geoscientific Lithospheric Experiment) were used as additional constraints in …


Why Don't People Read The Manual?, David G. Novick, Karen Ward Oct 2006

Why Don't People Read The Manual?, David G. Novick, Karen Ward

David G. Novick

Few users of computer applications seek help from the documentation. This paper reports the results of an empirical study of why this is so and examines how, in real work, users solve their usability problems. Based on in-depth interviews with 25 subjects representing a varied cross-section of users, we find that users do avoid using both paper and online help systems. Few users have paper manuals for the most heavily used applications, but none complained about their lack. Online help is more likely to be consulted than paper manuals, but users are equally likely to report that they solve their …


Usability Over Time, Valerie Mendoza, David G. Novick Sep 2005

Usability Over Time, Valerie Mendoza, David G. Novick

David G. Novick

Testing of usability could perhaps be more accurately described as testing of learnability. We know more about the problems of novice users than we know of the problems of experienced users. To understand how these problems differ, and to understand how usability problems change as users change from novice to experienced, we conducted a longitudinal study of usability among middle-school teachers creating Web sites. The study looked at the use both the use of documentation and the underlying software, tracking the causes and extent of user frustration over eight weeks. We validated a categorization scheme for frustration episodes. We found …


Symmetry Operator For The Maxwell Equations, Jose O. Andrade Jul 2005

Symmetry Operator For The Maxwell Equations, Jose O. Andrade

Graduate Student Papers (Physics)

In this work is shown that when the background space-time is type D solution of the Einstein vacuum equations with or without cosmological constant, a symmetry operator can be found for the Maxwell equations, as a consequence of that each component of the electromagnetic spinor satisfies a decoupled equation and that all the vacuum type D metrics admit a two index Killing spinor. Besides, the Maxwell equations are solved when the background space-time is the Carter A metric.


The Quantum Anharmonic Potential With The Linear Delta Expansion, Luis M. Sandoval Jul 2005

The Quantum Anharmonic Potential With The Linear Delta Expansion, Luis M. Sandoval

Graduate Student Papers (Physics)

In this report the problem of solving the Schrödinger equation for an anharmonic potential is treated using the technique known as the linear delta expansion. The method works by identifying three different scales in the problem: an asymptotic scale, which depends uniquely on the form of the potential at large distances; an intermediate scale, still characterized by an exponential decay of the wavefunction; and, finally, a short distance scale, in which the wavefunction is sizable. The method is found to be suitable to obtain both energy eigenvalues and wavefunctions.


The Rotundity Of Large Planetary Objects, Adesanwo Moradeyo Dec 2004

The Rotundity Of Large Planetary Objects, Adesanwo Moradeyo

Graduate Student Papers (Physics)

The most obvious structural feature of planetary bodies is their roundness. This arises because of the dominate roles of the two effects of gravity and case of the deformation of matter, whether gas, liquid or solid. This project is about proving and solving out the time scale (τ ) of flow restoring the body to spherical shape when we consider a slightly deformed self-gravitating sphere and also checking for spherical of different planetary objects.


Modelling Stochastic Gene Expression, Olienka Patricia Fernandez Jul 2004

Modelling Stochastic Gene Expression, Olienka Patricia Fernandez

Graduate Student Papers (Physics)

No abstract provided.


Physica: The Newsletter Of Utep's Department Of Physics, Utep Department Of Physics Dec 2003

Physica: The Newsletter Of Utep's Department Of Physics, Utep Department Of Physics

The Department of Physics

Electronic newsletter of UTEP's Department of Physics, December 2003.


Physica: The Newsletter Of Utep’S Department Of Physics, Utep Department Of Physics Feb 2003

Physica: The Newsletter Of Utep’S Department Of Physics, Utep Department Of Physics

The Department of Physics

Electronic newsletter of the UTEP Department of Physics, February 2003.


Physica Junior!: The Newsletter Of Utep’S Department Of Physics, Utep Department Of Physics Oct 2002

Physica Junior!: The Newsletter Of Utep’S Department Of Physics, Utep Department Of Physics

The Department of Physics

Electronic newsletter for high school students interested in physics, Fall 2002.