Texas A&M University-Kingsville: AKM Digital Repository
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Phenomenological insights into Farsi heritage language maintenance among second-generation Iranian-Americans
No full textEven though the number of Iranian immigrants to the United States has increased since the 1970s in various states including Texas, meager research has been undertaken on Iranian-Americans and their challenges maintaining their heritage language, Farsi, and developing Iranian American identities. This qualitative study is intended to explore those challenges among second-generation Iranian-Americans in Texas. The study focuses on attaining an in-depth understanding of life experiences of 10 selected participants who were born and raised in the United States and live in Texas. Through the adoption of a hermeneutic phenomenological design (Patton, 2015), this study will investigate and collect data through face-to-face and open-ended interview questions, document study, and observations. Hermeneutic phenomenology will be utilized as an interpretive framework, method, and procedure of this study to explore the lived experiences of participants so as to better understand the sociopolitical, socioeconomic, and socioinstitutional effects upon the maintenance of Farsi as a heritage language and the formation of Iranian American identities
Evaluation and enhancement of biological treatment of volatile organic emissions at oil and gas production and refining industries
No full textPetrochemical refineries and production sites are considered as the second greatest source of volatile organic compounds (VOCs) emissions after vehicle exhausts. Some of these VOCs are toxic and some of them can create ground level ozone in the presence of sunlight. Biological systems which are based on the natural ability of microorganisms to utilize organic pollutants as their carbon and energy sources and transform them to less toxic compounds are considered among the most promising cost effective emission treatment methods. Less energy consumption and lower overall operational costs, fewer by-products generation and smaller carbon footprint are the main advantages of this technology as compared to conventional treatment systems.
In spite of several successful lab-scale applications of biological treatment technology for removal of hazardous compounds, there is still a need for pilot and field-scale experiments to evaluate the performance of this system for removal of complex industrial contaminants mixtures. Hence, the goal of this research was to investigate the performance, robustness and strength of a pilot and a field-scale biofiltration treatment unit for removal of fluctuant VOCs from downstream and upstream oil and gas production, respectively. Moreover, two strategies for improving bioavailability and biodegradability of hydrophobic VOCs were examined in the lab in order to optimize the removal efficiency of low water soluble compounds.
A pilot-scale biotrickling-biofiltration (BTF-BF) unit was evaluated for removal of VOCs from a wastewater sump at a coastal petrochemical refinery located in south Texas (Site 1: CITGO Corpus Christi Refinery). In the present PhD research and based on the notable results of the pilot test, the BTF-BF unit was scaled-up and implemented as a field-scale unit for elimination of VOCs from a tank battery in a production site at east Texas (Site 2: Apache TAMU#2). VOC emissions at both sites were sampled by 6 L SUMMA canisters analyzed using gas chromatography-mass spectrophotometry (GC-MS), following method TO-15. Aromatics were the most abundant compounds, followed by alkanes at site 1 in contrast to site 2 which was dominated by alkane emissions. During the operation of the pilot-scale unit at an empty bed residence time (EBRT) of 90 seconds, an average 85% removal for the total VOCs was achieved which was comparable to an average 55% removal efficiency at site 2 at an EBRT of 120 seconds using field-scale unit. This difference was because site 1 was mainly composed of readily biodegradable aromatic compounds while 90% of VOCs composition at site 2 was relatively recalcitrant alkanes.
While biofilters/biotrickling filters are being demonstrated as very efficient and cost-effective treatment technologies for removal of VOCs, poor performance has been observed for some hydrophobic VOCs due to low bioavailability. In another part of this PhD study, lab-scale experiments in liquid cultures were performed in order to evaluate effectiveness of fungal growth at acidic pH environments as well as application of surfactants on improving bioavailability and biodegradability of mixture of benzene and xylene (BX). A wastewater inoculum from the CITGO Corpus Christi Refinery was used as the microbial culture. BX-degrading microorganisms were enriched at neutral and acidic pH mineral medium to favor bacterial and fungal growth, respectively. Two synthetic nonionic surfactants (Brij 35 and Tween 20) and one biosurfactant (Saponin) were evaluated at neutral and acidic pH microcosm studies.
Bench scale experiments demonstrated that acclimating the wastewater inoculum at pH 4 increased fungal to bacterial ratio. The larger surface area of fungal to bacterial biofilms as well as hydrophobic aerial mycelia of fungi probably facilitated the BX uptake. Hence, the benzene removal increased from 72% at the pH 7 control culture to 83% at the pH 4 control culture. An increase of 22% was observed at the same experimental conditions for the o-xylene removal. The microcosm results revealed the highest percentage increase for the removal of benzene and oxylene at pH 7 occurred during the addition of 0.1 critical micelle concentration of Saponin (4 mg/L). On the other hand, Brij 35 was demonstrated as the optimum surfactant which was most favorable for enhancing the bioavailability and biodegradability of BX when fungi were used as the working consortium. In contrast, Tween 20 had a negative effect on the biodegradation of both benzene and o-xylene at any dose. The observed retardation was related to the toxicity of this surfactant which was confirmed by the plate count analysis. The experimental data fit well with a pseudo first-order biodegradation kinetics model. It was observed that benzene and o-xylene were biodegraded faster at pH 7 than pH 4 and the addition of an optimum surfactant type increased the microbial growth rate and biodegradability of these two VOCs in the mixture
Synthesis of flexure based translational springs
No full textTranslational springs are employed to generate desired force-displacement relationships. Conventional translational springs utilize elastic deformations of coiled spring strips to fulfill their functions. The two-dimensional output motion of a conventional translational spring is produced by the three-dimensional deformation of its coiled spring strip, which is bending plus twisting of the coiled spring strip. Different from conventional translational springs, flexure based translational springs have simple planar monolithic structures and are convenient to manufacture and maintain. The output translation of a flexure based translational spring is from the two-dimensional bending of its planar flexible members. This thesis research is focused on synthesizing flexure based translational springs.
The flexure based translational springs are synthesized in this research to generate large output translations with desired constant spring stiffness rates and without parasitic output translational drifts. Because of large deformation and geometric nonlinearity, the existing flexure based translational springs face difficulties that include spring stiffness deviation, parasitic output translational drift, and high stress in the deformed springs. This thesis research is motivated by surmounting the difficulties. The arrangements of flexible beams in a flexure based translational spring are analyzed. A method for synthesizing flexure based translational springs is presented. The method is demonstrated by synthesizing flexure based translational springs with different beam arrangements
On improved randomized response strategies in survey sampling
No full textRandomized response technique (RR) is a significant statistical method to study sensitive issue in survey sampling. In this thesis, we introduced new randomized response methods to collect data on sensitive issues. The bias and variance expressions for the new estimators of the parameters of interested were derived. The properties of the proposed estimator were studied through simulation study by using SAS codes
Ab-initio calculation of nonlinear optical susceptibilities in Germanium Quantum Dots
No full textThe 2nd order and 3rd order nonlinear optical susceptibilities of small Germanium Quantum Dots (GeQDs) is calculated using Time Independent Density Functional Theory (TIDFT) method implemented in SIESTA®. The symmetry breaking is observed due to surface termination which enhances χ(2) up to 299.1 pm/V promising a strong Second Harmonic Generation (SHG) in GeQDs. Diagonal components of χ(2) tensor are 52.5, 11.2, 299.1 pm/V, for xxx, yyy and zzz, respectively. The 3rd order susceptibility, χ(3) is within the range of (0.2-0.4)×10−18 m2/V2 which is close to the experimental values of bulk Germanium. The similarity between the results obtained to the experimental values strongly supports the reliability of this method in calculating the nonlinear optical susceptibilities of GeQDs and other nanostructures in general. This study suggests possibilities of enhancing SHG in GeQDs through symmetry breaking via surface termination and strain as well as suitability of this fast and less-computationally intensive Density Functional Theory (DFT)-based method in predicting nonlinear optical susceptibilities of nano structures
A multi-objective shelter allocation model for hurricane disaster relief
No full textWith the increasing occurrences of natural disaster strikes, how to efficiently evacuate and allocate disaster-affected residents to shelters becomes a necessary task for disaster loss reduction. In this research, a maximum covering based multi-objective model is developed for shelter allocation and resident’s evacuation. The model’s objectives are to maximize shelter coverage of vulnerable victims, minimize the total evacuation time and minimize the total area of all the shelters. The vulnerability is added to the shelter coverage objective function which helps to allocate more vulnerable victims like old, young, unemployed and disable. The vulnerability of each census block is calculated by using percentile rank. Weighted- sum objective approach is used to solve the multi-objective model. This paper analyzes the trade-off between sub-objectives by adding different weight indicating the importance of each objective. A case study of post- hurricane evacuation and shelter allocation in coastal counties of Texas is analyzed taking three scenarios in GAMS win64 24.9.1 using the proposed model
Facial emotion recognition using convolutional neural networks
No full textA lot of progress has been made in the field of Facial Emotion Recognition (FER) in the last decade with the advent of Deep Neural Networks (DNN) and Convolutional Neural Networks (CNN). Facial Emotion Recognition has always been a challenging problem for researchers as it is difficult to predict closely related emotions such as sadness and disgust because of how the facial muscles respond to these emotions. In this paper, a six-layer Convolutional Neural Network (CNN) is proposed to classify images from the FER2013 dataset obtained from Kaggle’s Facial Emotion Recognition Challenge. The network was trained on 28,709 labeled images consisting of human faces expressing seven basic emotions namely- Anger, Disgust, Fear, Happiness, Sadness, Surprise, and Neutral. The prediction accuracy was determined by running 3589 images in the test set through the proposed convolutional neural network. In this research, different CNN architectures were investigated and advanced techniques like Dropout and L2-Regularization were implemented achieving a prediction accuracy of 51.7% outperforming pervious works.
Keywords: Facial Emotion Recognition (FER), Convolutional Neural Networks (CNN), Learning Rate (LR), Dropout Regularization
Growth of neocholoris oleoabundans: a comparison between a closed system photo bioreactor and an open system photo bioreactor
No full textMicroalgae are micro organic plants that can produce biodiesel; therefore they can be used as a source of renewable energy. The source of the biodiesel is the algae’s lipids which are full of triacylglycerol (TAGs). Algae can be grown in an open system or a closed system. The most commonly used open system photo bioreactor is the raceway photo bioreactor (RWP), while the most commonly used closed system photo bioreactor is the tubular photo bioreactor. The RWP is commonly used in industrial large scale because of its advantages of using direct sunlight and taking carbon dioxide directly from the atmosphere, but at the same time it has many disadvantages such as accumulation in pollution from the environment, non-desired microalgae species, and aquatic animals that may influence on the cultivated algae. On the other hand, a closed system photo bioreactor is more expensive to build, and the light provided may not be at an optimal focus. Also, the carbon dioxide may not be able to be obtained directly from the atmosphere, so it may have to be provided from another source. However, the growth and cultivation of algae in a closed system can be controlled better, resulting in an algae with a higher bio-density which can also result in a higher amount of lipids content that can be later processed into biodiesel by transesterification
Social behavior and movement ecology of Nilgai antelope
No full textNilgai antelope (Boselaphus tragocamelus) are an exotic ungulate species in Texas. Native to India, Nepal, and Pakistan, nilgai have expanded into much of coastal southern Texas and northeastern Mexico since their introduction in 1924–1949. The presence of nilgai in Mexico and South Texas has complicated the eradication of cattle fever ticks (CFT; Rhipicephalus annulatus and R. microplus). Cattle fever ticks can transmit bovine babesiosis to cattle, a serious economic threat to the U.S. cattle industry. With CFT quarantine areas established in South Texas, ranches with infested cattle must comply with extensive eradication requirements. Wildlife can hinder eradication efforts because white-tailed deer (Odocoileus virginianus) and nilgai are alternative hosts for CFT. Control methods, such as acaricide-treated baits, are available for deer. Nilgai do not respond to bait, which is a major challenge for controlling the spread of CFT. One unique aspect of nilgai ecology is their use of latrines, or repeated defecation at a localized site. In addition, nilgai are not impeded by standard livestock fencing, and often push under fences at well-established crossing sites. The existence of these repeatedly visited areas present an opportunity for CFT treatment through application of acaricides using remotely activated sprayers. With limited information on nilgai ecology, there is pressure to understand nilgai latrine and fence crossing behavior to design efficient CFT treatment measures. I analyzed the density, size, activity, and placement of nilgai latrines. I used trail cameras to assess frequency, time of day, sex, and age of nilgai that used latrines and all animals that used fence crossings. Also, I used genetic markers to determine how many individual nilgai use latrines. Knowledge of nilgai movement and behavior will help identify areas to target with remotely activated acaricide sprayers. The results of this study will have important implications for the development of treatment methods for eradication of CFT in the U.S
Quantitative comparison of Texas test scores between elementary schools with microsociety and state averages
No full textMeeting standardized test benchmarks is a challenge for elementary school students in Texas. The problem is that some elementary schools do not meet the performance standards of the fourth-grade STAAR state test average. Problem-based learning is a model used in schools to initiate problem-solving skills with a hands-on approach to real-world learning that aids to increase knowledge and skills across disciplines. The concept of problem-based-learning (PBL) is the framework for this study. Based on principles posited by Piaget and Vygotsky, PBL focused on the active and collaborative process of learning based on cognitive and social constructivist learning theories. Microsociety is one PBL program. The goal of this study was to determine if there is a difference in the 2016-2018 mean proportion of students who met performance standards in STAAR reading, mathematics, and writing tests between elementary schools with the Microsociety program and elementary schools statewide. The sample of the study included 7 elementary schools in the state of Texas that had a Microsociety program during the 2016-2018 school years. A quantitative comparative design and one-sample t-test were used to compare the mean of elementary schools who met expectations in Texas schools with Microsociety to the population mean of all elementary schools in Texas. The results of this study indicated that there was no significant difference between STAAR reading, mathematics, and writing for schools with and without the Microsociety program for the 2016-2018 school years. These results suggest that having a Microsociety program in a school does not influence state standardized test scores. To confirm this key finding, replication of this study in other states is recommended