AUETD (Auburn University)
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A COMPREHENSIVE ASSESSMENT OF ALABAMA’S FUEL TAX ADJUSTMENT MECHANISMS AND ITS IMPACT ON TAXPAYERS’ FINANCIAL CAPACITY
Get PDFThis thesis presents a comprehensive evaluation of fuel tax adjustment mechanisms intended to address Alabama's transportation demands without exceeding taxpayers' financial capacity. The study focuses on assessing the effectiveness of current and proposed methodologies for adjusting fuel tax rates, and ensuring sustainable and equitable funding for transportation infrastructure.
The research addresses the growing funding gap in transportation infrastructure, driven by rising construction costs and evolving fuel consumption patterns. To promote a sustainable funding approach, this thesis developed the Alabama Department of Transportation Construction Cost Index (ALDOT_CCI), a robust tool designed to reflect average construction cost growth. This index serves as a critical resource for budgeting and financial planning within ALDOT. The study then employed a risk-based forecasting methodology, using Monte Carlo simulations to project future trends in construction costs, fuel tax revenues, and taxpayers' financial capacity over a 20-year period. This approach provides a probabilistic perspective on these key variables, highlighting their potential variability and implications for long-term sustainability.
A comparative analysis of the predicted values of the ALDOT_CCI, Gasoline Revenue Index (GRI), and Gasoline Tax Rate Index (GTRI) with the Taxpayer Financial Capacity Index (TFCI) was performed to assess the potential impacts of tax rate adjustments on ALDOT’s financial capacity and taxpayers. The analysis underscores the importance of aligning tax rate adjustments with ALDOT’s financial needs and taxpayers’ ability to absorb these changes.
The study proposes two innovative methodologies for adjusting fuel tax rates: a fixed annual percentage adjustment based on the ALDOT_CCI, and a modified adjustment cap and frequency based on the National Highway Construction Cost Index (NHCCI). These methodologies aim to provide a balanced and equitable framework for future transportation funding policies, ensuring that tax rate adjustments are responsive to economic conditions and taxpayer capacity.
The findings reveal a growing disparity between rapidly increasing fuel taxes and slower growth in taxpayer financial capacity, particularly since the implementation of the Rebuild Alabama Act. The study highlights the need for periodic tax rate reviews and adjustments, improved data collection and analysis, stakeholder engagement, and the development of risk mitigation strategies. It further highlights the importance of exploring alternative funding mechanisms and assessing the impact of technological advances on fuel tax revenues and infrastructure needs.
The study concludes with several recommendations for improving Alabama’s transportation funding mechanisms. These include periodic tax rate reviews, improved data analysis for decision-making, and stakeholder engagement to foster public support. The research also calls for exploring alternative funding mechanisms, such as public-private partnerships and electric vehicle fees, to diversify revenue streams as fuel consumption patterns evolve. By implementing the proposed strategies, Alabama can meet future challenges and opportunities while maintaining a strong and resilient transportation infrastructure that supports economic growth and public well-being
Hopfield Neural Networks: A updated Approach for Using Associative Memory to Improve Matrices
No full textModern Hopfield Neural Networks (MHNNs) are a class of neural networks renowned for their associative memory capabilities, which have broad applications in pattern recognition, optimization, and error correction. This dissertation explores the mathematical foundations, architectural nuances, and practical applications of MHNNs, focusing on the development of a novel energy function using the Concave-Convex Procedure (CCCP). The updated energy function enhances the network's convergence properties and robustness, addressing limitations of classical models such as low storage capacity and susceptibility to local minima.We demonstrate the efficacy of the update energy function through rigorous theoretical analysis and extensive simulation studies. Synthetic datasets with various distributional properties are generated to evaluate the network's performance in classification tasks. Our results indicate that the proposed MHNN model outperforms Original Hopfield networks and competes effectively with contemporary machine learning algorithms, including Support Vector Machines, Decision Tree, Random Forests, and Convolutional Neural Networks.In classifc Hopfield nerual network practical applications, we focus on image restoration tasks, successfully reconstructing highly corrupted images, and achieving high accuracy and low restoration error. This showcases the network's potential for real-world applications in fields such as bioinformatics, natural language processing, and healthcare diagnostics.This work not only underscores the capabilities of MHNNs in associative memory and optimization tasks but also paves the way for future innovations. By integrating advanced mathematical techniques and exploring hybrid approaches, this dissertation contributes significantly to the field of neural networks and machine learning, providing a robust framework for future research and application development
A Survey of Band Directors in the United States Regarding Barriers to Developing Successful Band Programs in Majority African American Public Secondary Schools
Get PDFThis study investigated barriers hindering development of successful band programs in majority African American secondary public schools and strategies employed by band directors to overcome challenges. A mixed-methods survey was administered to 247 participants, including 20 from majority African American public secondary schools and 227 from non-majority African American secondary schools. Quantitative data, contextualized by qualitative responses, indicated the top barriers in majority African American schools included funding and resources, socioeconomic challenges, and scheduling. Top strategies were collaborating with administrators, developing positive band culture, and providing student transportation. In contrast, non-majority African American schools identified scheduling, socioeconomic challenges, and competition with extracurricular activities as their top barriers, while developing positive band culture, connecting with feeder programs, and collaborating with administrators were their top strategies. Factorial ANOVA analyses indicated participants in Title 1 schools rated several barriers, including socioeconomic challenges and student mobility, higher than those in non-Title 1 schools. Also, participants in schools that were both Title 1 and had a majority African American student population rated scheduling significantly higher, indicating the combination of these factors exacerbated challenges. Future research should focus on a) longitudinal studies to determine how band programs in majority African American schools develop and maintain overtime, b) student perspectives to explore their experiences in these programs, c) innovative funding models to address financial limitations of band programs, and d) replicating the current study with a larger sample size to generalize findings
An Investigation of Work-Family Spillover Effect of Generation Z Employees in Chinese Hospitality Industry
No full textWork–family spillover is an important topic in the hospitality sector. However, there is a lack of research on work–family spillover among Chinese Generation Z hospitality employees, who have become integral to the workforce. Therefore, this study employed qualitative and quantitative approaches to examine the work–family spillover among Chinese Generation Z hospitality employees based on the Social Exchange Theory (SET) and Conservation of Resource (COR) Theory. In the qualitative phase, 33 participants from 14 hotels in five major cities in China were interviewed. The results showed that work could affect a family positively or negatively via its role as stressor, work and social supporter, and its characteristics (i.e. flexibility, salary). Family influenced work negatively as it could be a source of stress. However, family could also provide support to the employees. Supervisor support, co-worker support, and organization support were helpful to cope with negative work-family spillover. Furthermore, the qualitative study found that male and female employees have different issues from their work-family experience. In the quantitative phase, 313 Chinese Generation Z hospitality employees were recruited from five hotel properties and an online research platform. The findings indicated that organizational support and servant leadership influenced employees’ positive work-to-family spillover (PWFS) and negative work-to-family spillover (NWFS); workload only significantly influenced NWFS. NWFS and PWFS influenced exhaustion, job stress, and turnover intention. Only PWFS positively influenced work performance. Moreover, family emotional support positive influenced positive family-to-work spillover (PFWS). PFWS and negative family-to-work spillover (NFWS) significantly affected turnover intention, exhaustion, and family satisfaction. Gender only moderated the impact of PFWS on turnover intention. Theoretically, this study documented positive and negative work–family experiences and advanced the COR Theory and SET and identified some unique work-family issues in Chinese hospitality industry. Practically, the findings can help hotel managers in planning and implementing strategies to balance Generation Z employees’ work and family lives (e.g., providing flexible scheduling, training program, and firm activities), thereby sustaining talents
Exploring the State of Student Food Insecurity Response among Alabama College and University Campuses: Development, Evaluation, and Pilot Implementation of the Campus Food Aid Self-assessment Tool (C-FAST)
No full textFood insecurity is an important issue among college students with negative effects on academic performance, physical and mental health, and socialization. Currently, no instrument exists to systematically guide campus support providers in the development and prioritization of food insecurity response. This study sought to develop, evaluate, and pilot an instrument to assess resources, practices, and policies of college campuses in response to food insecurity.
The researcher established a framework for assessing campus food insecurity response with six dimensions: Student Services and Supports; Involvement; Advocacy; Awareness and Culture Efforts; Education and Training; and Research, Scholarship, and Creative Works. Using the framework, the researcher developed the Campus Food Aid Self-assessment Tool (C-FAST), a cross-sectional, criterion-based survey. Expert panel review and cognitive interviewing were established face and content validity of the newly developed instrument.
Next, the researcher piloted the survey Alabama college campus representatives (n = 22). Internal consistency tests confirmed the reliability of the tool (Cronbach’s ≥ 0.60 for each dimension). C-FAST responses were scored from 1.0 (no to minimal response) to 4.0 (best practice achieved), and the mean C-FAST score was 2.33 (SD = 0.41).
The author used an independent samples t-test and one-way MANOVA to determine whether the extent of campus responses to food insecurity differed based on institutional level. Both tests indicated greater response to food insecurity among four-year institutions when compared to two-year institutions (p < .05). Univariate effects suggested two-year campuses had a significantly lower mean Research, Scholarship, and Creative Works score than four-year campuses (p = .001). The author used backward stepwise regression to explore which campus characteristics may predict changes in campus food insecurity response. The model was significant (p < .001), and institutional locale (p = .015) and prevalence of food insecurity on campus (p = .005) were identified as potential predictors of food insecurity response.
This study established the first evidence-based framework to assess responses to food insecurity. It also included the first statewide study of comprehensive food insecurity response. Results can help guide prioritization of campus food insecurity response and future research and policy decisions associated with campus food insecurity
Nanoscale Modification of Lignocellulosic Biomass Components for Value-Added Applications
No full textThe primary goal of this dissertation was to understand how modification of lignocellulosic nanomaterials enhances their properties for value-added applications. This is essential for meeting the current demand for sustainable alternatives. To offset the impacts of climate change while supporting a growing world population, “green” alternatives are required for many traditional, synthetic materials. This dissertation describes two key applications utilizing biomass waste to support sustainability. First, this research investigated the production of tailored activated carbons from fundamental biomass components. This effort resulted in models which allow for predictable, yet tunable activated carbon properties. The bio-derived carbons were then used in water treatment applications for PFAS removal to understand which activated carbon properties and feedstock component affect contaminant adsorption. Second, this research explored the surface functionalization of cellulose nanocrystals with functional biomolecules to develop efficient nanocarriers for agricultural applications.
In recent decades, there has been significant interest in using biomass to produce activated carbon for environmental remediation and energy storage applications. Previous studies have concentrated on individual biomass sources, neglecting the interactions among lignocellulosic components crucial to determine activated carbons’ structural properties and suitability for a variety of applications. This chapter sought to address this knowledge gap by exploring how the relative compositions of cellulose nanofibers, cellulose nanocrystals, xylan, and lignin affected the resulting properties of activated carbons produced through a two-step chemical activation process. Simplex-lattice mixture designs were used to understand how the composition affected activated carbon specific surface area and micropore fraction. Mixture regression models showed that specific surface area was highest when the activated carbon was composed of 17% cellulose nanofibers and 17% cellulose nanocrystals sourced from wood pulp and 67% alkali kraft lignin by mass. In addition, the micropore fraction was largest with a precursor mixture of 50% cellulose nanocrystals and 50% lignin by mass. The presence of xylan in the feedstock mixtures did not impact the resulting activated carbon properties in a predictable manner. Equations produced by this work were experimentally validated to within 10% of the model values. The results of this investigation provide a foundation for future efforts to tune activated carbon properties based on feedstock biomass composition.
In response to strict regulations by the United States Environmental Protection Agency regarding per- and polyfluoroalkyl substance (PFAS) concentrations in drinking water, the application aspect of this work investigated the efficacy of activated carbons derived from agricultural waste components for water treatment. By varying the proportions of lignin, cellulose nanocrystals, and cellulose nanofibers in the feedstock mixtures, specific PFAS adsorption efficiencies ranged from 31 to 98%, indicating that biomass structure influences contaminant adsorption. Activated carbon prepared from a mixture of 50% lignin, 35% cellulose nanocrystals, and 15% cellulose nanofibers achieved over 98% removal of three regulated PFAS compounds without requiring additives or surface functionalization. In addition, this mixture effectively removed four unregulated short and long-chain PFAS. Specific surface area was shown to be the most critical factor in determining PFAS adsorption, and both positive and negative surface charges are beneficial to harness hydrophobic and electrostatic interactions. Conversely, cellulose nanofibers in the precursor led to lower adsorption. The combination of these two investigations aids in developing a structure-process-property relationship for the adsorption of contaminants from groundwater using biomass-derived activated carbons.
More sustainable agricultural practices are also critical to meeting humanity's food needs while minimizing adverse environmental impacts. Engineered nanomaterials used as nanocarriers promise to reduce the volume of agrochemicals required for efficient crop production but concerns about contamination of agricultural products motivate the use of naturally occurring alternatives. In the second portion of this research, plant-derived cellulose nanocrystals were investigated as “green” alternatives to synthetic nanomaterials for the delivery of agrochemicals to plants. The production of fluorescently labeled cellulose nanocrystals demonstrated that these nanocrystals could penetrate the plant cell wall and enter cells without causing any adverse effects on the overall plant phenotype, genome, and metabolome. The efficiency of these nanocarriers to deliver chemicals was demonstrated by the covalent conjugation of cellulose nanocrystals with the common herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Plant cell culture experiments confirmed that cellulose nanocrystals can be used as a 2,4-D nanocarrier and reduce the volume of plant growth regulators needed to cultivate plant cells. To further probe the use of cellulose nanocrystals as a carrier for a variety of agricultural biomolecules, plasmid DNA was electrostatically bound to cellulose nanocrystals to carry genetic information to the plant cell. Results showed that cellulose nanocrystals are effective at carrying genetic material to the target site in the plant cell and can do so at rates better than other biomolecules. The schemes described are the first reports of herbicide and DNA-conjugated cellulose nanocrystals. Additionally, this work creates a new platform for cyclical agricultural practices where cellulose nanocrystals extracted from agricultural waste can be used for the direct delivery of agrochemicals to crops, thereby reducing the environmental burden created by both agricultural waste and excess herbicides.
Overall, this dissertation advanced understanding and utilization of lignocellulosic nanomaterials through microscale modifications, which is crucial for enhancing sustainability and moving towards a greener economy. This work bridges fundamental research with practical applications and provides insight into the structure-property-processing relationships essential for advancing the use of biomass-derived nanomaterials in large-scale operations. By repurposing waste biomass into functional nanomaterials, humans can create innovative and sustainable solutions from materials that are often viewed as waste
Mechanical Property Evolution in Lead Free Solders Subjected to Various Thermal Exposure Profiles
No full textWith the growth of electronic packaging used by various industries, ranging from automobiles to hand-held products, reliability is a major concern. Also, to keep pace with the increasing demand of end users for integration, miniaturization, light weight, high speed, and multi-functionality of portable electronic devices such as mobile phones, digital cameras, as well as personal digital assistant (PDA), electronic packaging industries are attempting to manufacture packages of high density and smaller dimensions. These packages consist of smaller solder joint interconnects with reduced spacing between the solder joints. The reliability of smaller electronic packages is greatly affected by the environment and application where it is being used.
Solder joints provide mechanical support, and electrical and thermal interconnection between packaging levels in microelectronics assembly systems. Proper functioning of these interconnections and the reliability of the electronic packages depend largely on the mechanical properties of the solder joints. Lead free solders are common as interconnects in electronic packaging due to their relatively high melting point, attractive mechanical properties, thermal cycling reliability, and environment friendly chemical properties. However, Lead free electronic assemblies are often subjected to thermal cycling during qualification testing or during actual use. During the dwells at the constant high temperature extreme, the lead free solders joints will experience thermal aging phenomena, resulting in microstructural evolution and material property degradation. Additional aging effects can also occur in the ramp periods from low to high temperature. Also, CTE mismatches between the silicon die and PCB causes shear fatigue of the solder joints and affects the reliability of the entire package. Many studies have been conducted to investigate the effect of isothermal aging on lead free solder alloy properties and the reliability of assemblies. However, no study has focused on how thermal cycling with different profiles (ramp and dwell times) affects the mechanical property evolution in lead free solders. This research involves several projects to create a database of mechanical properties of bulk and real solder joints, and the associated mechanical and microstructural evolution under different thermal exposures.
In the first project, several different SAC+Bi solder alloys with various bismuth contents were investigated. In particular, a family of SAC+Bi alloys with 1%, 2%, and 3% Bi were studied with four different thermal exposure profiles (isothermal aging, slow thermal cycling, thermal shock, and thermal ramping). The primary objective of this study was to determine how much bismuth is needed in the lead-free alloy to mitigate microstructure and material property evolutions during thermal exposures. Use of lower Bi content can lower solder cost and also increase reliability in high strain rate loadings such as shock/drop/vibration. Uniaxial test specimens were prepared by reflowing solder in rectangular cross-section glass tubes with a controlled temperature profile. After reflow solidification, the samples were placed into the environmental chamber and thermally cycled from -40 C to +125 C under a stress-free condition (no load). Several thermal cycling profiles were examined including: (1) 150 minute thermal cycles with 45 minutes ramps and 30 minutes dwells, (2) air-to-air thermal shock exposures with 30 minutes dwells and near instantaneous ramps, and (3) 90 minute cycles with 45 minutes ramps and 0 minutes dwells (thermal ramping only), (4) no cycling (simple aging at high temperature extreme). After the preconditioning, mechanical properties including stress-strain were explored at room temperature. Stress-strain behavior under different thermal exposures has been compared in terms of exposure time. Mechanical behavior under different thermal exposures has been compared to explore the most detrimental thermal exposures.
In the second project, the effects of thermal exposures on the creep behaviors of SAC+Bi solders were studied. A controlled temperature profile was used during the preparation of rectangular cross-section uniaxial test specimens by reflow solidification. After fabrication, the samples were exposed to various types of thermal pre-conditioning (aging, cycling, or ramping) for varying amounts of time (0-20 days) in a stress-free environment (no load). Finally, creep testing at room temperature was performed on the pre-conditioned specimens. Creep tests were performed at three different stress levels (σ = 10, 12, and 15 MPa), and the secondary creep strain rates were measured. The changes in the creep strain rate for the SAC+Bi solder alloys were measured for each type of thermal exposure and for different exposure times. Results for the SAC+Bi alloys were then compared to prior results for SAC305, and it was observed that adding bismuth had the beneficial result of significantly reducing the creep rate degradations. Higher levels of bismuth led to increased mitigations of the thermal degradation effects.
In the third project, the evolution of mechanical properties of both SAC305 and SAC+Bi solder joints under different thermal exposures have been explored. Mechanical properties were recorded as modulus, hardness, and yield strength. Mechanical properties were extracted using nanoindentation technique. For nanoindentation, samples were prepared by attaching the package on epoxy mold using glue followed by grinding, polishing, and finally optical microscopy (OM) to find out single grain joint for avoiding grain orientation effect on mechanical properties. After the sample preparation, all samples were preconditioned and then tested at room temperature to measure the mechanical properties. For each exposure time, 10 indents were made in a row and average was taken to extract the mechanical properties. Mechanical properties were compared under different thermal exposures with exposure time for each solder alloy. Also, mechanical properties evolution under different thermal exposures for both bulk solder and solder joint of SAC+Bi alloys were compared to observe the effect of thermal exposures on small scale and large scale specimen.
In the final project, the microstructure evolutions occurring in lead free solders subjected to several different thermal exposure profiles (isothermal aging, slow thermal ramping, and slow thermal cycling) were investigated and then the observed changes in microstructure were correlated with the previously measured mechanical property and creep behavior evolutions. For the microstructural study, a slot was made on an epoxy mold and the sample was inserted into the slot followed by grinding, polishing, and exposed in a thermal chamber for 0, 1, 5, and 20 days. After exposing the samples to different thermal profiles, the samples were viewed in an SEM to depict their microstructures, and various attributes of the microstructures (e.g. IMC particle size, particle spacing, dendrite size, etc.) were measured as a function of the thermal profile and exposure time. Correlations of the observed microstructure evolutions with the corresponding changes in mechanical properties and creep behavior were performed for each alloy, and it was demonstrated that the Ag3Sn IMC particle size (diameter) was the most significant characteristic of the microstructure that controls the SAC lead free solder mechanical behavior. More importantly, it was observed that for given alloy, the mechanical property degradation depended on the IMC particle diameter in same manner irrespective of thermal profile that caused the mechanical and microstructural evolutions. This suggests that a single curve/relation can be used for each alloy to correlate mechanical behavior and microstructure, independent of the thermal history seen by the solder. This means that, one need merely look at the microstructure of the solder to know its mechanical behavior
Oxy-Steam Fluidized Bed Gasification of Southern Pine Biomass, Lignite Coal, Plastic Wastes, and their Blends for Hydrogen Production
No full textRising energy demand, climate change, and waste management issues drive the need to convert waste into energy via thermochemical conversion processes such as gasification. This study explores the potential of producing syngas from the oxy-steam fluidized bed gasification of various feedstocks, including southern pine biomass, municipal plastic wastes, lignite coal, and their blends. Twelve distinct blends were analyzed, focusing on combustion reaction kinetics, stability, and comprehensive combustion indices. It was found that increasing the biomass content in the blends improves both combustion stability and performance. The optimal blend, consisting of 60% biomass, 10% coal, and 30% municipal waste plastic, exhibited the lowest activation energy of 110 kJ/mol. Following the characterization and optimization of these blends, oxy-steam fluidized bed gasification experiments were conducted for various feedstocks. Notably, gasification of municipal plastic waste at 950°C, with a steam-to-carbon ratio of 3 and an equivalence ratio of 0.2, yielded syngas with the highest hydrogen concentration of 52.54 vol.%, followed by coal at 49.10 vol.%. The syngas compositions from these experiments were used to develop gasification kinetics models for biomass, coal, and plastics by implementing inversion problem of chemical kinetics with genetic algorithm as an optimization tool. The developed genetic algorithm-based gasification kinetic model outperformed conventional models, achieving low average absolute errors in predicting syngas compositions. Additionally, the developed kinetic models for biomass, coal, and plastics were integrated into a 2D Eulerian-Eulerian computational fluid dynamics (CFD) model using ANSYS Fluent, which reliably predicted syngas compositions. Moreover, low-temperature oxy-steam fluidized bed co-gasification was conducted at temperatures ranging from 715 to 745 °C on 50/50 blends of biomass and various plastic wastes including polyethylene terephthalate, high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene. The syngas compositions obtained from these gasification experiments were used to develop kinetic models for each type of plastic waste. These kinetic models were then integrated into a 2D Eulerian-Eulerian CFD model using ANSYS Fluent. The model accurately predicted the syngas compositions from the gasification of different plastics, achieving average root mean squared errors of 2.57%, 3.12%, 3.76%, 4.54%, and 4.91% for C₂-C₃, CH₄, CO, H₂, and CO₂ gases, respectively
Climate-Smart Agriculture: Building A Resilient Cocoa Industry In Ghana
No full textThe Study is a three-paper article dissertation. The purpose of the first paper is to examine smallholder farmer's perception of climate change in cocoa production in Ghana. The study employs shifts in environmental parameters—rainfall, temperature, and the duration of wet and dry seasons—to assess farmers' perceptions of climate change. The purpose of this study was to examine farmers’ perceptions to climate change and their relationship with socioeconomic and institutional factors. A systematic random procedure was used for this study. Multiple regression analysis and descriptive analysis including frequencies, percentages, means, standard deviations, and correlations were done. The findings indicated that most farmers observed variations in rainfall, temperature, and the duration of wet and dry seasons. Farmers’ perceived changes in climate corresponded with weather data from the study district. Farming experience and gender demonstrated a notable correlation with farmers' climate change perceptions. Farmers strongly agreed to be interested in learning about farm-level adaptation practices to climate change. Farmers also strongly agreed to take risks by changing their current farming practices to adopt climate change adaptive practices.
The second paper examines smallholder farmers' perception of climate-smart agricultural practices as an adaptation practice to climate change in Cocoa production. The research employs Rogers' (2003) Diffusion of Innovations theory and the Theory of Planned Behavior to explain the socioeconomic and institutional determinants influencing the adoption of climate-smart agricultural practices among cocoa farmers. A systematic random procedure was used for this study. Descriptive analysis including frequencies, percentages, means, standard deviations, and binary logistic regression were done. The majority of the farmers in this study were male (62,2%), have secondary education (47.2 %) and were between the age of 45-59 years old. Most farmers have received training (93%), were members of farmer groups (92%) and have access to extension services (98%). The findings further show that gender, education and training positively and significantly influence farmers’ adoption of climate-smart agricultural practices in the study communities.
The third paper discusses an advisory paper focusing on the adoption of drip irrigation in Haiti, as a climate-smart technology. This paper is a conceptual framework paper employing Roger (2003) Diffusion of Innovation theory to explain the sets, challenges, and benefits to adopting drip irrigation for vegetable farmers in Haiti.
Keywords: Climate Change Perception, Cocoa (Theobroma cacao), Management Practices, Climate-Smart Agriculture, Extension Support, Socioeconomic Factor
Reevaluating copper sulfate pentahydrate dosing for harmful algal bloom control
No full textCopper sulfate pentahydrate is the most widely used chemical means of controlling nuisance algal growth that often lead to harmful algal blooms (HABs). However, its efficacy and ultimate ecological impact are closely tied to key water quality parameters known as toxicity-modifying factors (TMFs). A substantial body of research has demonstrated limitations in current copper dosing methods, which rely predominantly on alkalinity and frequently result in the application of higher doses than necessary to manage nuisance algae. To establish a more precise and efficient copper algaecide dosing strategy, a multiple linear regression (MLR) model was developed to relate copper toxicity to phytoplankton with respect to key TMFs, including pH, dissolved organic carbon (DOC), alkalinity, and hardness. The quantified relationships led to a novel dosing equation that integrates site-specific pH and DOC measurements for targeted copper applications.
In Chapter 1, I tested this MLR-based dosing approach against the standard alkalinity-based dosing method in a large-scale field mesocosm experiment. Results indicated that the MLR-based dose, which was 60% lower than the traditional alkalinity-based dose, selectively reduced harmful cyanobacterial populations while minimizing overall ecological impact.
Chapter 2 extended this analysis over time by examining the efficacy of the MLR-based dosing approach through multiple applications in a 42-day mesocosm experiment. Findings from this study confirmed that the MLR-based doses continued to outperform alkalinity-based doses, with a half-MLR dose, almost nine times lower than the standard alkalinity dose, producing the best water quality (i.e., highest transparency) throughout the experiment. Importantly, non-target effects of copper on zooplankton and beneficial green algae were nearly eliminated.
Together, these studies establish a foundation for a more sustainable, targeted, and cost-effective copper algaecide dosing strategy. The MLR-based dosing approach offers a promising advancement for HAB control that optimizes copper use while reducing environmental impact for long-term water quality management