Texas A&M University-Kingsville: AKM Digital Repository
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Effect of blended freshwater on growth and development of Solanum lycopersicum
No full textA total of 175 Solanum lycopersicum plants were grown to study the physiological characteristics of the species grown with unconventional water. All plants in the five treatments were arranged in a randomized complete block design (RCBD), at the Department of Agriculture, Agribusiness, and Environmental Science (AAES) greenhouse. Each treatment had 35 plants with five replications. The treatments that were diluted from 53.065 mS/cm seawater included: 0.5%, 1%, 1.5%, and 2% and a freshwater control. Plants were treated weekly and data
collection occurred within the same period. Physiological and growth medium parameters measured include height, changes in electrical conductivity of the soil and water, changes in soil pH, total chlorophyll content, transpiration rates, leaf area and fruit yield. Statistical analysis of
data showed significant differences in the electrical conductivity of the growth medium with increase in seawater concentration, but no significant differences existed between the other parameters measured
Population demographics of Nilgai in southern Texas
No full textNilgai antelope (Boselaphus tragocamelus) are bovids that are endemic to India and portions of Pakistan and Nepal. They were introduced into South Texas in the 1920’s and now have a free-roaming population of approximately 37,000 individuals. There is little known about
nilgai population demographics, and their populations appear to be continuing to rise across its introduced range. For this reason, our objectives for this study were to (1) determine where nilgai are found throughout the landscape and quantify the landscape structure around nilgai locations, (2) determine a reliable aging method for aging nilgai in the field, and (3) determine nilgai
reproductive capabilities in southern Texas. We collected nilgai point-locations from aerial surveys to assess the landscape structure around observed nilgai locations. We then performed a fine scale landscape analysis that quantified the scale of effect of landscape structures surrounding the nilgai locations and then performed a broad scale analysis that determined nilgai habitat use
versus availability. Nilgai harvests were conducted during the summers of 2018-2021. From each harvested nilgai, we took complete dentition photos, collected the central incisors and the right mandible, and assessed the pregnancy and lactation status of each female. If a fetus was present, it was sexed, and the crown-rump length was measured. Our results revealed that, during the
wintertime, nilgai were commonly observed on shrublands and woodlands. We were able to determine 13 tooth eruption stages and 6 age classes for female nilgai which can be used to age nilgai in a field-based setting. Overall, out of the sexually mature nilgai cows, 79% were pregnant and 55.5% of those pregnancies were carrying twins. Our results will provide land managers with
the tools necessary to properly assess nilgai populations which will be essential in managing and controlling their populations in the future
Effects of prescribed burning on butterfly populations in Coastal South Texas
No full textBackground: Pollination is a key biological process that enables fertilization and production of seeds for plants. Animals such as mammals, birds, and insects such as butterflies and bees serve as primary pollinators. Butterflies are an important pollinator worldwide, however, climate change and invasive species are affecting regional populations in the United States, prompting a need to manage pollinator habitat. Land managers often use prescribed burning, to mimic natural fires which provides benefits, such as removal of dead plant matter, increases in nutritional value of plants and forb diversity communities, nutrient recycling. The objective of this study was to determine effects of different seasons of prescribed burning on butterfly populations in the South
Texas Coastal Marsh and Prairies ecosystem. I aimed to evaluate different burning intervals to inform management recommendations to maximize the value of rangeland for butterfly populations.
Results: Season of burn did not have a treatment effect on butterfly abundance, diversity, or family richness. This was the same across cordgrass and non-cordgrass plant communities.
Conclusion: This study site may be an appropriate burn treatment that will benefit butterfly pollinators as it has different seasons of burns, time return-intervals between burns to allow time for recolonization and areas of no-burn refugia
Simulation of huff-n-puff gas injection in unconventional reservoirs with natural fractures using discrete fracture networks modeling
No full textUnconventional reservoirs are stimulated by hydraulic fracturing. The induced hydraulic fractures and existing natural fractures complicates the prediction of reservoir hydrocarbon recovery. It is important to describe both types of fractures so as to adequately account for complex
reservoir heterogeneities, fluid transport, and storage mechanisms. This study simulated the enhanced oil recovery (EOR) in an unconventional reservoir by huff-n-puff gas injection through combining the discrete fracture network (DFN) and local grid refining (LGR) modeling
approaches in Petrel combined with compositional simulation in eclipse. The well performance
from a field producing from the Eagle Ford shale formation by huff-n-puff carbon dioxide (CO2) injection was simulated. The log-generated and published petrophysics and fluid data for the formation were used to build up the 3-D model. The hydraulic fractures were defined by dual
porosity/dual permeability model using LGR approach in Petrel. Stochastic DFN methodology was applied to generate natural fractures by using probability density functions (PDF). This method allows for discrete modeling of the natural fractures as against an equidistant approach
and greatly improves the accuracy and effectiveness of the model. The effects of the natural fracture parameters including orientation, length and standard deviations from base-case fracture length were analyzed. The orientation of the natural fractures affects production from naturally fractured reservoirs. The oil recovery factor reaches the highest at both dip and azimuth angles of 45 degrees. The azimuth angles results in higher production changes compared to a similar change in dip angles. A linear proportionality exists between natural fracture length and oil production and a 5% - 20% standard deviation around the mean length does not result in a significant change
in productivity
Investigation of reservoir fluids effects on underground hydrogen gas storage
No full textThe underground hydrogen storage method is a significant strategy for preserving surplus electrical energy, which is converted into hydrogen during periods of peak production to prevent wastage. Considering the low energy density of hydrogen per unit volume, it requires a large volume capacity for storage. The depleted natural gas reservoir has been established as a promising option for accommodating the required storage capacity.
This research investigated the effect of reservoir fluids characterized by component compositions and temperature (dry, wet, and condensate gas) on the recovery and quality of hydrogen storage and production. The dry, wet, and condensate fluids were simulated in a discretized conceptual model that uses Adaptive-Implicit EOS. Following the depletion of the reservoir, hydrogen gas was injected for storage and withdrawn after a shut-in period. Subsequently, the impacts of hysteresis, solubility, diffusivity, storage cycling, and cushion gas injection were evaluated on the purity and recoverability of hydrogen stored in depleted gas reservoirs.
It was discovered that the production of hydrogen at 98% purity is impeded by the co-production of the native gases from the depleted reservoir. It was also noted that the purity of hydrogen produced decreased as more native gases found their way into the production stream, thereby reducing the purity of hydrogen. The gaseous molecular diffusion, gravity segregation, gravity override, and solubility are the major mechanisms influencing the movement and mixing of hydrogen gas that is partly due to its relatively low density compared to other native gases. The dry gas reservoir exhibited the highest recovery rate, followed by the condensate gas reservoir, and lastly, the wet gas reservoir. Notably, the ISO purity requirement of 98% was upheld throughout the experiment. Moreover, condensate dropout contributes to the trapping of hydrogen gas, alongside hysteresis, solubility, and aqueous diffusion into the deeper region of the reservoir where connate water exists. Furthermore, it was observed that the introduction of cushion gas helped increase the reservoir pressure. Finally, when the purity criterion was considered, nitrogen was found to be more suitable than carbon dioxide
Damage reduction to non-structural elements in hurricane prone area
No full textResearchers in the field of science and engineering have been looking for ways to curb hurricane damage which is a global threat that occurs from time to time and which has led to loss of life and property. The occurrence of hurricanes can be predicted and its damaging effect
can be reduced to by designing the structures to be able to resist hurricane forces. The aim of this research is to provide recommendations to reduce hurricane related damage in nonstructural elements in schools and government facilities located along Texas coast. Experience gained from previous hurricane shows that many structures that suffered devastating effects or
collapsed did not meet current building code requirements [1, 2, 3, 4,17]. To explore the effects of hurricane forces acting on a structure, a structure that survives hurricane will be analyzed using building codes and compare with those observed in the field .An analysis will also be
made for some non-structural elements. Recommendation will be made to avoid potential damage to non-structural elements produced by different wind effect, or combined effects of wind, deterioration, construction defects and water
Connectivity and sensing coverage in 3D terrains using Voronoi Tessellation
No full textIn recent sensor technology advancements, one of the major challenging issues is to design an optimal deployment method of sensors for surveillance, monitoring, and others in the 3D environment. In random sensor deployment, the network cannot achieve an accurate coverage ratio. However, there are different existing methods that have been proposed for sensor deployment and optimization. Moreover, it is necessary to consider the coverage and connectivity of sensor nodes in the environment where the sensors are deployed. In this approach, we propose a Voronoi-based novel algorithm in 3D terrain. The proposed algorithm employs Voronoi Tessellation and optimization techniques for efficient sensor placement, ensuring coverage and connectivity in 3D WSNs. In this state, we ensure that every point in 3D space is within the communication range while ensuring network connectivity. Simulation results validate the algorithm's effectiveness in diverse scenarios. The research contributes to the field by providing a structured approach to 3D sensor network deployment, with potential applications in various areas such as environmental monitoring and industrial automation
Trajectory tracking of a four-wheeled robot
No full textA four-wheeled robot has been used for a very long time in industries. Most four-wheeled robots are designed to follow a specific path to reach the final position to perform their activity. Four-wheeled robots have evolved and are designed to plan and follow a specific path to get a goal position. Reaching the goal position requires the mobile robot to plan its trajectory and avoid obstacles based on its operating workspace. The four-wheeled robot's kinematics and dynamics are analyzed to develop a control algorithm for the robot to track its trajectory. Kinematics and dynamics models are generated based on the input parameters of operating conditions and the robot's geometry. The developed kinematic and dynamic model for Ackermann steering was implemented in a MATLAB environment, and simulation results were obtained to test the designed model. It was desired to achieve trajectory tracking with precision. The Simulink model was developed for the car-like Ackermann steering model to obtain the vehicle's pose based on the vehicle's speed and steering rate. Using the inverse kinematics model, another mathematical model was developed to determine the vehicle speed, steering angle, and pose based on the provided waypoints. The effect of steering saturation on trajectory tracking of the robot with Ackermann steering was also studied. Trajectory tracking of the car-like wheeled mobile robot with front-wheel steering implementation and simulation in MATLAB was successfully achieved using the Ackermann model, Pure pursuit algorithm, and adaptive pure pursuit algorithm
Measuring the impact of service-learning activities on authentic leadership
No full textThe purpose of this study was to assess the impact that service-learning activities had on authentic leadership in the AGRI 4350 Collective Leadership in Agriculture course at Texas A&M University-Kingsville during the Spring semester of 2023. The goal for this study was to determine the student’s authentic leadership by issuing the Authentic Leadership Questionnaire (ALQ). The sample consisted of 29 students within the AGRI 4350 Collective Leadership course. Pre- and post-tests of the ALQ were administered during the course in order to determine students perceived level of authentic leadership progress before and after the completion of the course. We also sought to measure any perceived impacts on authentic leadership after having led two college wide service learning events. This included an assessment on the ALQ and comparisons to student demographic characteristics. After comparison of the pre to post-test scores, it was found service-learning events had a minor positive impact on students perceived authentic leadership. Upperclassmen had a more significant difference than underclassmen. Males had a more pronounced difference in scores than females after taking the class and taking part in service learning events. It is recommended that this research be replicated with a larger sample population and compared to outside of the 4350 course to the college as a whole
Cryptography approaches in wireless sensor networks a survey study
No full textThe aim of the study is a survey of Cryptography approaches in wireless sensor networks. The data is acquired using secondary data from published articles and available studies. The researcher reviewed more than 100 papers that are related to the topic. This study’s main result and conclusion is the superiority of private key cryptographic algorithms over their asymmetric public key algorithms. Together with various lightweight hashing techniques, they have been proven to be robust and have enough security to meet any challenge. It is quite suitable for use in the WSN field. In addition, among the public key techniques, ECC exhibits the best performance in terms of less time and space complexity as well as better security performance than other techniques