Physical Sciences and Mathematics Commons^™

Geochemical Studies Of Backfill Aggregates, Lake Sediment Cores And The Hueco Bolson Aquifer, Anita Thapalia

Open Access Theses & Dissertations

This Dissertation comprises of three different researches that focuses on the application of geochemistry from aggregates, lake sediment cores and Hueco Bolson Aquifer. Each study is independent and presented in the publication format. The first chapter is already published and the second chapter is in revision phase. Overall, three studies measure the large scale (field) as well as bench scale (lab) water-rock interactions influenced by the climatic and anthropogenic factors spans from the field of environmental geology to civil engineering.

The first chapter of this Dissertation addresses the chemical evaluation of coarse aggregates from six different quarries in Texas. The …

Growth And Analysis Of Micro And Nano Cdte Arrays For Solar Cell Applications, Brandon Adrian Aguirre

Open Access Theses & Dissertations

CdTe is an excellent material for infrared detectors and photovoltaic applications. The efficiency of CdTe/CdS solar cells has increased very rapidly in the last 3 years to ~20% but is still below the maximum theoretical value of 30%. Although the short-circuit current density is close to its maximum of 30 mA/cm2, the open circuit voltage has potential to be increased further to over 1 Volt. The main limitation that prevents further increase in the open-circuit voltage and therefore efficiency is the high defect density in the CdTe absorber layer. Reducing the defect density will increase the open-circuit voltage above 1 …

Resampling-Based Multiple Comparisons For Generalized Linear Models, Josephine Sarpong Akosa

Open Access Theses & Dissertations

Diverse applications in medical and epidemiological research routinely utilize generalized linear modeling to explain the relationship between the incidence of disease and particular risk factors. Researchers' interest in such models are estimated quantities from the model such as the response probabilities, the relative risks or the odds ratios and not the model itself. Often, the simultaneous estimation of these quantities or a subset of the quantities are warranted. The results are usually reported via confidence intervals at a pre-specified level of significance. Utilizing the usual 95% pointwise confidence intervals for the simultaneous inference inflates the risk of making type I …

A New Bivariate Distribution With Applications, Sathya Amarasekara

Open Access Theses & Dissertations

We construct a bivariate distribution of (X, Y ) by assuming that the conditional distribution of Y given X is a two-parameter Gamma (s, ν(x)), where the scale parameter depends on X. If X is assumed to be any distribution, then clearly the joint distribution is well defined in all cases. We will study this new distribution by developing all possible properties, moments, shapes and estimation of parameters with a view towards applications of the distribution to data from many random number generation methods.

Simulation Of Heat And Mass Transfer In Suns River Solar Distillation, Houman Azari

Open Access Theses & Dissertations

Many regions around the world have limited fresh water resources, and we need to desalinate brackish water resources for drinking and irrigation purposes. Most of the world is also facing energy challenges which encourages engineers and scientists to use renewable energy resources instead of hydrocarbon fuels. Arid regions such as the Middle East, many African countries, and the southwestern United States typically have abundant solar irradiance and brackish or saline water supplies. Solar-thermal desalination could be an important supply of fresh water in these regions.

The classic solar still is not efficient for providing large amounts of clean water for …

A Study Of Ti-Doped Wo3 Thin Films Using Comparative Theoretical And Experimental Approach, Aurelio Paez

Open Access Theses & Dissertations

Metal oxides like Tungsten Oxide (WO3) are well documented and characterized in the literature, with uses in darkening windows and mirrors, flat computer displays, solar panel cooling, and sensors (of interest in this study). Ti doping of WO3 is less documented and the focus of this study. Sample thin films of pure WO3 and varyingly Ti doped WO3 were prepared using Radio Frequency magnetron sputtering (RF) (13.56 MHz) to grow thin films on a silicon substrate. This study aims to compare multiple Ti doping percentages in WO3 theoretically and then compare with experimental data taken from thin films of various …

Multi-Dimensional Emotion Recognition From Geometry And Color Information, Geovany A. Ramirez

Open Access Theses & Dissertations

Emotions play a fundamental role in everyday interactions among humans. Humans are adept at expressing themselves and interpreting others through a multi-modal, subtle and complex process using non-verbal cues including speech prosody, facial expression, eye gaze, body gestures, head motion, posture, and skin color changes. However, recognizing the affective state of humans is a difficult task for computers.

Automatic emotion recognition has focused on analysis of the six discrete basic emotions: happiness, sadness, surprise, fear, anger and disgust. However, humans express more complex and subtle affective states such as confusion, shame, pleasure, anxiety or depression. Therefore, a different representation based …

Exploring The Hydrogeologic Controls On Brackish Water And Its Suitability For Use In Hydraulic Fracturing: The Dockum Aquifer, Midland Basin Texas, Francisco Ruben Reyes

Open Access Theses & Dissertations

Water scarcity in arid regions can limit or impede certain hydrocarbon production activities, such as hydraulic fracturing and well drilling. The Midland Basin, a major oil-producing area in semi-arid far west Texas and the eastern sub-basin of the Permian Basin, is already impacted by limited freshwater availability. A typical tight oil well in the Midland Basin requires ~3.8-11.4 x 103 m3 of water per fracture treatment (Nicot et al., 2012). Despite draught conditions and limited resources, data for 2011 indicate freshwater comprises ~70% of the water used in hydraulic fracturing in the Midland basin. Thus, the Midland Basin represents an …

Numerical Investigation Of Impact Of Relative Humidity On Droplet Accumulation And Film Cooling, Luz Irene Bugarin

Open Access Theses & Dissertations

During the summer, high inlet temperatures affect the power output of gas turbine systems. Evaporative coolers have gained popularity as an inlet cooling method for these systems. Wet compression has been one of the common evaporative cooling methods implemented to increase power output of gas turbine systems due to its simple installation and low cost. This process involves injection of water droplets into the continuous phase of compressor to reduce the temperature of the flow entering the compressor and in turn increase the power output of the whole gas turbine system. This study focused on a single stage rotor-stator compressor …

Structural And Geochronologic History Of Southern Alaskan Blueschists, Erik M. Day

Open Access Theses & Dissertations

Detrital zircon data are presented from the Liberty Creek blueschist in the central Chugach Mountains which indicate two distinct periods of the preservation of blueschist facies metamorphism along the southern Alaskan margin. A maximum depositional age of ~136 Ma demonstrates that the Liberty Creek schist was deposited long after the Jurassic cooling ages (196-185 Ma; Lopez-Carmona et al., 2011) recorded in western Alaskan blueschist bodies, revealing two blueschist preservation events. This Early Cretaceous depositional age also indicates that there have been major reorganizations within this subduction complex because the Potter Creek assemblage, directly south of the Liberty Creek schist, is …

Spingolipid Metabolism In A Reptillian Protozoan, Entamoeba Invadens, Duran Dogan Debons

Open Access Theses & Dissertations

Entamoeba invadens (hereinafter E. invadens) is an anaerobic parasitic protozoan that can be found in water and soil. Although the host organisms for this parasite are snakes, lizards, and other reptile species, the parasite is morphologically identical to Entamoeba histolytica, a causative agent of human amebiasis. Entamoeba inavdens exists in two morphological forms--(1) a replicative trophozoite, and (2) a relatively dormant cyst. While the transformation of cyst to trophozoites (called "excystation") takes place in the stomach, the differentiation of trophozoites to cyst (known as "encystation"), occurs in the small intestine. Unlike the cyst, a trophozoite is unable to survive …

Environmental Assessment Of Used Motor Oil In The Ciudad Juarez-El Paso Area, Alma Leticia Figueroa

Open Access Theses & Dissertations

As a hazardous waste generated in large amounts worldwide, used motor oil (UMO) is an important issue for environmental science. UMO contains the carcinogenic and mutagenic compounds Polycyclic Aromatic Hydrocarbons (PAHs). Unless properly managed and disposed of PAHs remain in the environment, principally in sediments and soil. From such environmental sinks, PAHs can migrate to watersheds contaminate drinking water, and damage ecosystems and human health.

Generators of used oil include "businesses that handle used oil through commercial or industrial operations or from the maintenance of vehicles and equipment," (United States Environmental Protection Agency (USEPA), 2013). An example of such a …

Contributions To Global Optimization Using Interval Methods And Speculation, Angel Fernando Garcia Contreras

Open Access Theses & Dissertations

Most electronic devices we are familiar with, such as cell phones and computers, are small and require similarly small electronic components arranged and connected in small areas. Finding the right size and arrangement of the components inside a device can be a challenge. The manufacturing process of the components limits their possible size, some components have specific needs to operate at a certain speed, and the total area of the device is also limited. In portable devices, these designs have one important objective: that the entire device consumes the minimum amount of electricity possible, so the device can keep functioning …

Uptake Of Copper And Cerium By Alfalfa, Lettuce And Cucumber Exposed To Nceo2 And Ncuo Through The Foliage Or The Roots: Impacts On Food Quality, Physiological And Agronomical Parameters, Jie Hong

Open Access Theses & Dissertations

Nanotechnology is increasingly attracting attention not only for its variety of applications in modern life, but for the potential negative effects that nanomaterials (NMs) can cause in the environment and human health. Studies have shown varied effects of engineered nanoparticles (ENPs) on plants; however, most of these studies focused on the interaction of NPs with plants at root level. The increasing production and use of NPs have also increased the atmospheric amounts of NPs, which could be taken up by plants through their leaves. Cucumbers (Cucumis sativus L.) are broad leaf plants commonly grown both commercially and in home vegetable …

Synthesis And Characterization Of Platinum(Ii) Complexes Of Electron Donor And Acceptor Ligands, Namrata Khanal

Open Access Theses & Dissertations

Pt(II) complexes of N,N-diphenylpyridineamine or 4-diphenylphosphino derivatized triphenylamine as novel electron donors and alkynyl derivatized benzothiadiazole as electron acceptors were synthesized. All the complexes were characterized by 1H and 13C nuclear magnetic resonance spectroscopy, electronspray ionization mass spectrometry, infrared spectroscopy, and 31P nuclear magnetic resonance spectroscopy for the complexes of 4-diphenylphosphino derivatives. The electronic properties studied using UV/vis spectroscopy exhibit ᴫ-ᴫ* transition, metal to ligand charge transfer, and optical highest occupied molecular orbital-lowest unoccupied molecular orbital bandgaps from 2.62-2.65 eV. The electrochemical study performed using cyclic voltammetry have shown the highest occupied molecular orbital-lowest unoccupied molecular orbital bandgaps from 2.70-2.74 …

Experimental Investigation Of Syngas Flame Stability Using A Multi-Tube Fuel Injector In A High Pressure Combustor, Sergio Elzar Maldonado

Open Access Theses & Dissertations

Over 92% of the coal consumed by power plants is used to generate electricity in the United States (U.S.). The U.S. has the world's largest recoverable reserves of coal, it is estimated that reserves of coal will last more than 200 years based in current production and demand levels. Integrated Gasification Combined Cycle (IGCC) power plants aim to reduce the amount of pollutants by gasifying coal and producing synThesis gas. SynThesis gas, also known as syngas, is a product of coal gasification and can be used in gas turbines for energy production. Syngas is primarily a mixture of hydrogen and …

Application Of Stir Bar Sorptive Extraction Thermal Desorption Gas Chromatography Mass Spectrometry For The Study Of Water Accommodated Fractions Of Fossil Fuels And Biodiesel, Ricardo Mccreary

Open Access Theses & Dissertations

Even though measures are taken to decrease accidental release of crude oil and refined fuels into the aquatic environment, continued demand of such fuels--particularly in the transportation sector--pose a continued threat to the aquatic environment throughout their handling, processing, and consumption. Even though measures can be taken to remove the visible layers of fuel in water, it has been shown that constituents of these fuels--that partition into water--can have adverse health effects on the aquatic organisms at low concentrations that are not necessarily predictable through the study of the actual fuel's original composition. Consequently, this renders the need for an …

Approximate Nature Of Traditional Fuzzy Methodology Naturally Leads To Complex-Valued Fuzzy Degrees, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

In the traditional fuzzy logic, the experts' degrees of confidence in their statements is described by numbers from the interval [0,1]. These degree have a clear intuitive meaning. Somewhat surprisingly, in some applications, it turns out to be useful to also consider different numerical degrees -- e.g., complex-valued degrees. While these complex-valued degrees are helpful in solving practical problems, their intuitive meaning is not clear. In this paper, we provide a possible explanation for the success of complex-valued degrees which makes their use more intuitively understandable -- namely, we show that these degrees naturally appear due to the approximate nature …

Finding The Best Function: A Way To Explain Calculus Of Variations To Engineering And Science Students, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practical problems, we need to find the most appropriate function: e.g., we need to find a control strategy u(t) that leads to the best performance of a system, we need to find the shape of the car which leads to the smallest energy losses, etc. Optimization over an unknown function can be described by the known Euler-Lagrange equations. The traditional way of deriving Euler-Lagrange equations when explaining them to the engineering and science students is, however, somewhat over-complicated. We provide a new, simpler way to deriving these equations, a way in which we directly use the fact that …

Why 20? Why 40? A Possible Explanation Of A Special Role Of 20 And 40 In Traditional Number Systems, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

Both historical and linguistic evidence shows that numbers 20 and 40 played a special role in many traditional numerical systems. The fact that, e.g., the same number 20 appears in unrelated cultures such as Romans and Mayans is an indication that this number must have a general explanation related to human experience. In this paper, we provide a possible explanation of 20 and 40 along these lines: namely, we show that these numbers can be identified as the smallest sample sizes for which we can extract statistically significant information.

Dialect Or A New Language: A Possible Explanation Of The 70% Mutual Intelligibility Threshold, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

In most cases, linguists have a consensus on when people from different regions speak two different dialects of the same language (and can, thus, understand each other reasonably well) or two different languages (in this case, their mutual intelligibility is limited). In most cases, this intuitive consensus corresponds to a 70% mutual intelligibility threshold: if at least 70% of the words from one region are understandable to people from another region, then these are two dialects, otherwise these are two different languages. In this paper, we provide a possible explanation for this 70% threshold.

Feasible Algorithms For Lattice And Directed Subspaces, Jennifer (Hamlyn) Del Valle, Vladik Kreinovich, Piotr Wojciechowski

Departmental Technical Reports (CS)

In some practical situations (e.g., in econometrics), it is important to check whether a given linear subspace of a space R^m with component-wise order is a lattice -- and if it is not, whether it is at least a directed ordered space. Because of the practical importance, it is desirable to have feasible algorithms for solving these problems -- which in Computer Science is usually interpreted as algorithms whose computation time does not exceed a polynomial of the length of the input. No such algorithms were previously known. In this paper, we present feasible algorithms for solving both problems.

Towards Designing Optimal Individualized Placement Tests, Octavio Lerma, Olga Kosheleva, Shahnaz Shahbazova, Vladik Kreinovich

Departmental Technical Reports (CS)

To find the current level of a student's knowledge, we use a sequence of problems of increasing complexity; if a student can solve a problem, the system generates a more complex one; if a student cannot solve a problem, the system generates an easier one. To find a proper testing scheme, we must take into account that every time a student cannot solve a problem, he/she gets discouraged. To take this into account, we define an overall effect on a student by combining "positive" and "negative" problems with different weights, and we design a testing scheme which minimizes this effect.

"And"- And "Or"-Operations For "Double", "Triple", Etc. Fuzzy Sets, Hung T. Nguyen, Vladik Kreinovich, Olga Kosheleva

Departmental Technical Reports (CS)

In the traditional fuzzy logic, the expert's degree of confidence d(A & B) in a complex statement A & B (or A\/B) is uniquely determined by his/her degrees of confidence d(A) and d(B) in the statements A and B, as f_&(d(A),d(B)) for an appropriate "and"-operation (t-norm). In practice, for the same degrees d(A) and d(B), we may have different degrees d(A & B) depending on the relation between A and B. The best way to take this relation into account is to explicitly elicit the corresponding degrees d(A & B) and d(A\/B), i.e., to come up with "double" …

Knowledge Geometry Is Similar To General Relativity: Both Mass And Knowledge Curve The Corresponding Spaces, Francisco Zapata, Vladik Kreinovich

Departmental Technical Reports (CS)

In this paper, we explain and explore the idea that knowledge is similar to mass in physics: similarly to how mass curves space-time, knowledge curves the corresponding knowledge space.

Fuzziness And Bayesian Analysis In Engineering, Matthias Stein, Michael Beer, Vladik Kreinovich

Departmental Technical Reports (CS)

An engineering analysis requires a realistic quantification of all input information. The amount and quality of the available information dictates the uncertainty model and its associated quantification concept. For inconsistent information, a distinction between probabilistic and non-probabilistic characteristics is beneficial. In this distinction, uncertainty refers to probabilistic characteristics and non-probabilistic characteristics are summarized as imprecision. When uncertainty and imprecision occur simultaneously, the uncertainty model fuzzy randomness appears useful. In a Bayesian approach the fuzzy probabilistic model provides the opportunity to take account of imprecision in data and in prior expert knowledge. The Bayesian approach ex-tended to inconsistent information is demonstrated …

Why Triangular Membership Functions Work Well In F-Transform: A Theoretical Explanation, Jaime Nava, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practical applications, it is useful to represent a signal or an image by its average values on several fuzzy sets. The corresponding {\em F-transform} technique has many useful applications in signal and image processing. In principle, we can use different membership functions. Somewhat surprisingly, in many applications, the best results occur when we use triangular membership functions. In this paper, we provide a possible theoretical explanation for this empirical phenomenon.

Finding Specifications Of While Statements Using Patterns, Aditi Barua, Yoonsik Cheon

Departmental Technical Reports (CS)

A formal correctness proof of code containing loops such as while statements typically uses the technique of proof-by-induction, and often the most difficult part of carrying out an inductive proof is formulating a correct induction hypothesis, a specification for a loop statement. An incorrect induction hypothesis will surely lead to a proof failure. In this paper we propose a systematic way for identifying specifications of while statements. The key idea of our approach is to categorize and document common patterns of while statements along with their specifications. This is based on our observation that similarly-structured while statements frequently have similarly-structured …

Algebraic Product Is The Only T-Norm For Which Optimization Under Fuzzy Constraints Is Scale-Invariant, Juan Carlos Figueroa Garcia, Martine Ceberio, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practical situations, we need to optimize under fuzzy constraints. There is a known Bellman-Zadeh approach for solving such problems, but the resulting solution, in general, depends on the choice of a not well-defined constant M. We show that this dependence disappears if we use an algebraic t-norm (and-operation) a * b, and we also prove that the algebraic product is the only t-norm for which the corresponding solution is independent on M.

From Urysohn's Universal Metric Space To A Universal Space-Time, A. G. Aksoy, Z. Glassman, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

A known Urysohn's result shows that there exists a universal} metric space, i.e., a metric space into every other (separable) metric space can be isomorphically embedded. Moreover, this universal metric space can be selected to be ultra-homogeneous -- every isomorphism of its two finite subsets can be extended to the isomorphism of the whole space.

Starting with Einstein's theories of Special and General relativity, space-times are described by a different type of structure -- a set (of events) equipped with the proper time t(a,b) between points a and b; such spaces are known as space-times with kinematic metric, or k-space-times. …