Texas A&M University-Kingsville: AKM Digital Repository
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Population and habitat assessment of the California, mountain, and Gambels quails in Californias changing landscape
No full textCalifornia is an ecologically diverse state that supports California quail (Callipepla californica), Gambel’s quail (Callipepla gambelii), and mountain quail (Oreortyx pictus) populations. The state has experienced sweeping land use changes in the past half-century, leading to potential loss of habitat for these three species due to the impacts of urbanization, large-scale agriculture, and changing forest and rangeland management. Our goal was to determine the long-term population trends for the California, mountain, and Gambel’s quail in California and quantify how changes in land use and land cover impacted localized changes in relative abundance. We used the number of birds detected per route from the North American Breeding Bird Survey (BBS) to create five-year rolling average abundance maps. We established 30 – 50 random points within the geographic ranges of each species in California and extracted the number of birds detected per route from 1970 to 2017. We identified areas within the state that had declining, increasing, and no change in species’ abundances and compared road density (1992 - 2010), human population density (1990 - 2010), land use (1969-2017), and land cover (1986-2019). On the geographic-range scale in California, populations of all three quails did not experience long-term declines over the 45-year period of the BBS data. Areas where California quail abundances declined had 68% higher road densities and 130% higher human population densities in 2010, and 95% less bare ground and 48% less litter cover in 2019 than sites where they were increasing. Where mountain quail abundances were declining, irrigated land was 153% higher in 2017 but road density was 50% lower in 2010 than where they were increasing. Areas with increasing Gambel’s quail abundances had 119% lower human population densities and 91% lower road densities in 2010, and 47% less bare ground cover in 2019, than the area where abundances were decreasing. Our results indicate that these species can persist in a human-dominated landscape if sufficient quality habitat is available
A comparative study of the effects of elementary bilingual education programs on emergent bilinguals' STAAR reading scores in South Texas
No full textThis research uses a descriptive quantitative statistical design to examine campus-level results from the State of Texas Assessments of Academic Readiness (STAAR). The focus is on describing the achievement disparities between campuses that implemented Transitional Bilingual Education (TBE) programs and those implementing Dual Language (DL) programs. By disaggregating the performance data, the study analyzes the mean STAAR performance of emergent bilingual (EB) students on campuses using TBE and DL models. It utilizes 2017-2019 campus and EB STAAR performance data for third through fifth grade in reading, obtained from the Texas Academic Performance Reports (TAPR).
The following research questions will guide the study: (1) What are STAAR reading scores for emergent bilinguals in transitional bilingual education programs for third, fourth, and fifth grades? (a) Describe, compare, and analyze data for EB students in TBE programs from 2017-2019 in third, fourth and fifth-grade. (2) What are STAAR reading scores for emergent bilinguals in dual language bilingual education programs for the third, fourth, and fifth grades? (b) Describe, compare, and analyze data for EB students in DL programs from 2017-2019 in third, fourth and fifth-grade. (3) Do STAAR reading scores differ between transitional bilingual education and dual language programs for third, fourth, and fifth-grade emergent bilinguals?
This research utilizes achievement gap metrics (Rodriguez et al., 2016; Stevens, 2017) to examine the TAPR report data and delineate the achievement disparities(effect size) between the mean performance of emergent bilingual (EB) students at schools with TBE programs and the mean performance of EB students at schools with DL programs in the context of the STAAR assessment.
The comprehensive data gathered from diverse educational levels, encompassing district, state, and regional levels, unveils a striking disparity in academic outcomes between schools implementing Transitional Bilingual Education (TBE) and those embracing a Dual Language (DL) model. The findings illuminate that schools applying TBE did not attain academic results on par with other educational institutions, while those adopting a DL model achieved or exceeded the academic performance levels of the district, state, and region. Furthermore, a compelling pattern emerges when comparing the two bilingual models, illustrating the consistent superiority of schools utilizing a DL approach in academic performance over those employing TBE. These insights vividly underscore the efficacy of the DL model in providing bilingual education and fostering academic achievement among emergent bilinguals, surpassing the outcomes of TBE models
Automating welding processes with dual-robot systems
No full textAutomating welding processes requires the implementation of predictive models and simulations that enable more effective application, control, and welding through parameter optimization. The manufacturing of metal structures faces imminent challenges in an increasingly competitive market, demanding efficient resource utilization to reduce production costs and streamline manufacturing cycles.
In this context, the modern industry calls for automated and robotic systems that simplify tasks, promote continuous improvement, and elevate the quality of manufactured products. Robotic welding is experiencing rapid advancement, driven by the accelerated development of electronics and computing, essential foundations for controlling robotic arms.
A distinctive feature of robotics is the close collaboration between robots and humans, both in shared workplaces and in multimodal interaction. This phenomenon exemplifies ongoing development and progress in industrial applications, but also reflects the ongoing evolution of welding towards a more efficient, competitive scenario aligned with market demands.
Since 2010, Olson International has had two robotic arms, which, unfortunately, have remained inactive until now. The imperative need to put this equipment into operation is a crucial step for the company, with direct implications for increased productivity and substantial improvement in quality processes. This strategic move aims not only to optimize production volume but also to reduce manufacturing costs, decrease reliance on outsourcing, and mitigate risks associated with human labor in industrial environments.
In terms of quality, the challenge lies in designing welding procedures tailored to different positions, sheet thicknesses, steel grades, and combinations of protectors. The key is to fully deploy the capabilities of the Fanuc robotic arm, leveraging its six degrees of freedom to obtain additional benefits derived from its versatility, flexibility, and scalability.
My contribution to this thesis has been the installation, conservation, and programming of the Fanuc robots, and in particular, the time needed to weld each piece was significantly reduced, going from 3 minutes to just 52 seconds per piece.
This reduction in cycle time not only has a direct impact on productivity, allowing further parts to be produced in less time, but also has important counteraccusations in terms of cost and quality. By speeding up the manufacturing process, costs associated with labor and outfit operations can be reduced, helping to ameliorate the overall profitability of the operation.
This allows the company to more fluently acclimate to changes in client requirements and remain competitive in a dynamic and constantly evolving business terrain.
Furthermore, there is an opportunity to consider collaborative projects or interinstitutional alliances. These initiatives could not only provide support mechanisms but also facilitate continuous improvements, ensuring the optimal use and technological application of the robotic arms. This proactive approach not only addresses potential challenges but also maximizes the potential benefits associated with the integration of this advanced technology into Olson International's processes
Global supply chain risk management analysis: an Ishikawa approach during & post COVID-19 Pandemic in USA
No full textResearch on the global supply chain primarily focuses on managing risks among international businesses across countries. The COVID-19 pandemic severely disrupted global supply chains, highlighting the critical need for risk identification and assessment during crises. This enables international organizations to develop strategies for mitigating future supply chain risks.
To achieve the study objectives, the thesis proposes utilizing the Ishikawa fishbone method for Root Cause Analysis to identify COVID-19-induced supply chain risks. Identifying root causes is essential for effective risk mitigation and enhancing future supply chain operations. Subsequently, the research suggests integrating the Supply Chain Flexibility, Agility
& Responsiveness (SCFAR) Framework post-COVID to bolster supply chain resilience.
The study advocates for effective risk management to predict and prevent future disruptions, considering the adverse impact of COVID-19 on global businesses, customers, and the economy. Despite pre-pandemic safety measures, COVID-19’s consequences include global scarcity, delayed lead times, and reduced customer satisfaction.
The study's findings propose enhancements to existing risk management frameworks, offering valuable insights to benefit key stakeholders involved in global supply chains
Stabilization of sulfate-rich soil with electric arc furnace slag
No full textTexas soil is difficult to stabilize due to its unique combination of salts, crystals, and minerals. Conveniently, lime and cement stabilizers have been used to increase soil strength, hardness, and durability. However, in Texas, conventional stabilizers are known to be useless in soils high in sulfates because high-sulfate soil contains soluble sulfates and soluble carbonates. This means that when lime and water are added to sulfate-rich soil, a chemical reaction occurs that forms new minerals such as
thaumasite and ettringite, the minerals that cause heaving. Sulfate-induced heaving can be seen as lumps or waves on pavements and can destroy a newly built roadway. To resolve sulfate-induced heaving, researchers have been looking for effective ways for controlling the swell potential of sulfate-rich soils. Currently, electric arc furnace slag has been proposed to reduce the swell potential of sulfate-rich soils. Moreover, since the study of
electric arc furnace slag as a stabilizer is new approach, it will be used to stabilize soil known to possess sulfates. So, in this research, sulfate-rich soil will be treated with electric arc furnace slag. Experiments will include one soil sample treated with 5% electric arc furnace slag with an
additional 1% lime, and another soil sample will contain 6% electric arc furnace slag by itself. In addition, a treatment with a 6% lime on the sulfate-rich soil will be studied. All treated soil samples went through a few hours of a mellowing period and a slight increase in their optimum moisture content. An untreated sample of the same soil was also prepared to compare its swell with the swell of the treated soil samples. The samples were compacted into proctor molds and submerged in water for three days and an expansion index was determined. The study's outcome showed that the untreated soil produced a measurable expansion. No measurable expansion was
found for the 6% lime-treated soil and no signs of expansion for the 5% EAFS with 1% lime. On the 6% electric arc furnace slag, however, signs of collapse rather than expansion were measured, and the expansion index rendered a negative number as if the sample became more compact leading to a conclusion that electric arc furnace slag may be a usable alternative solution for stabilizing soil that contains a moderate number of sulfates
The impact of race on social support among Black and White families in the United States
No full textWhat is the frequency of familial interaction among people from Black and White racial backgrounds? Adding onto the previous question, are there any racial differences in the types of social support that people receive from their families? This study aims to answer these questions by examining variations in familial contact and the types of social support provided by Black and White families in the United States. Social capital theory will be used to help emphasize the importance of resources gained from positive social connections within relationships. Social capital will be measured and conceptualized in this study by examining the strength of social networks through frequency of contact that individuals have with their most contacted family members. The types of social support individuals receive will also be used as a measure of social capital by evaluating the different ways that individuals turn to their families for help. This study uses data from collected from across the United States through the 2018 General Social Survey to provide the results for the two hypotheses of this study. This study posits two hypotheses: (1) Black families are more likely than White families to have more frequent contact with one another, and (2) Black and White families provide different types of social support to each other
Effects of pile driving vibrations on young concrete in steel-concrete bond strength
No full textConstruction equipment such as impact pile driving has been known to cause ground vibrations that can lead to damage on concrete structures. This work attempts to understand how pile driving forces can affect the integrity of young concrete structures in steel-concrete bond strength with the use of a Safeguard Seismic Unit (SSU) 5500 GeoSonics seismograph. The seismograph needed to be fully understood before recording pile driving vibrations, so the construction of a single degree of freedom shake table was constructed and helped the group understand that our recordings with this instrument fall within a 1.2 % efficiency. With this known, we took the seismograph out to a US Hwy 77 pile driving project where the group obtained vibrational recordings of three piles containing a maximum peak particle acceleration (PPA) of 13.2 ft/sec² (0.41 g’s). The group then recreated a pile driving mechanism with a maximum peak particle acceleration of 0.488 g’s to disturb 20 concrete cube specimens, which were then tested in steel-concrete bond pullout. The results of our steel-concrete bond testing give the group a glimpse into what may be happening to young concrete specimens when disturbed with in-field pile driving vibrations. The day 3 samples from our Group 1 specimens relay that damage may be occurring to our specimens when 40 blows are placed onto the concrete cubes. When accelerations and number of blows are amplified, the Group 2 specimens from day 4 show us that the bond strength has reduced as well. With more testing in the future, a recommendation can be made to disturb young concrete as late as four days of curing for best results
Smart electric vehicle charging pad using X, Y, Z dimensions to avoid under and over coupling between coils for maximum power transfer efficiency
No full textEfficiency of Power Transfer (PTE) is one of the most significant factors in Electric Vehicle (EV) wireless charging using wireless power transfer (WPT) and the power transfer efficiency highly depends upon the Transmitting(Tx) and Receiving(Rx) coil radius and the optimum distance between the same. However, in the recent past, many researchers have tried to make the Tx coil variable so that high mutual inductance (M) can be achieved for maximum power transfer still some of them have maintained the Tx and Rx coil radius constant and changed the distance for optimum power efficiency. Still misalignment between the coils is one of the big issues that has compromised the efficient power transfer. Therefore, In order to facilitate the optimum PTE, maximum alignment is the key to achieving the same where the Distance between the Tx and Rx coil is of critical importance because a large distance will decrease the efficiency and a small distance will cause over-coupling and this will also result in less power transfer, so, to resolve this issue, we used controller-based approach in which Tx coil will be attached to a controller based motor which will move in X,Y and as well as Z axis to avoid a large and too close distance in order to find optimum distance so maximum power transfer efficiency can be achieved. The results will be shown for the same
Ballistic impact on multi-layered armor structure
No full textIn this research, a multi-layered armor structure was introduced by having ceramics as a face-plate and a stacking of Kevlar as intermediate layer. The backing plate was a monolithic structure made of Aluminum alloy. Simulation models were developed in ABAQUS/Explicit to predict the ballistic resistance performance of structure in different scenarios. Thinner versions of the proposed structure were manufactured and experimented by using a powered vacuum cannon, which was developed by a graduate student researcher associated with the research grant. Different ballistic impact experiments were finished with impact velocity of projectile ranged from 90 m/s to 130 m/s. Residual velocity of projectile was monitored and damage on the target panel was analysed. The simulation models were partially validated with acceptable correlation between numerical and experimental results. Then the studies of ballistic impact on 40 mm thick multi-layered structures were conducted under high impact velocity 800 m/s. With the same total thickness, the structure with 20 mm thick Boron carbide layer and 10 mm thick Kevlar/epoxy layer absorbed more kinetic energy than the structure with 10 mm thick Boron carbide layer and 20 mm thick Kevlar/epoxy layer. The multi-layered structure with Kevlar/epoxy panel in the front was damaged more significantly compared to the structure with Boron carbide front plate. Cohesive layers reduced delamination of Kevlar/epoxy layers and enhance ballistic resistance of multi-layered structure
ONOFIC pull-up technique for minimizing subthreshold leakage in CMOS
No full textThe thesis addresses the critical challenge of subthreshold leakage current in advanced CMOS technologies, a dominant factor in static power dissipation in modern integrated circuits. This research proposes a novel ONOFIC (ON-OFF IC) pull-up technique to significantly reduce subthreshold leakage while maintaining circuit performance.
The study presents a comprehensive analytical model capturing the physical and circuit-level mechanisms contributing to subthreshold leakage. A specialized ONOFIC circuit topology is proposed, utilizing force stacking and floating transistor configurations. This structure enables high resistance in the OFF state for leakage suppression and low resistance in the ON state to support normal operation.
The design is implemented and simulated using LTspice with predictive CMOS technology models. Benchmark test circuits, particularly SRAM blocks, are used to demonstrate the ONOFIC technique's applicability. Simulation results reveal a 23.122% reduction in leakage current—from 153.543nA to 118.040nA—without significantly compromising performance.
This work contributes to the field of low-power VLSI design by:
1. Introducing a novel low-leakage pull-up method;
2. Developing mathematical models for subthreshold behavior;
3. Establishing guidelines for ONOFIC integration in CMOS design; and
4. Validating the effectiveness of the method using circuit-level simulations