An Involution Satisfying Particle-In-Cell Method

Thesis (Ph.D.)--Michigan State University. Computational Mathematics, Science and Engineering - Doctor of Philosophy, 2025This thesis presents a new Particle-in-Cell method for numerically simulating plasmas under the Vlasov-Maxwell system. Maxwell's equations and the Newton-Lorentz force are both recast in terms of vector and scalar potentials under the Lorenz gauge. This results in a set of decoupled wave equations governing the potentials and a Hamiltonian system with a generalized momentum formulation governing the particles. The Particle-in-Cell framework for solving a plasma system requires two main components, a method for updating the fields and a method for updating the particles of the system.The first part of this thesis introduces the Method of Lines Transpose, or MOLT, as a way of solving partial differential equations in general and the wave equation in particular. Additionally it introduces a new particle pusher, the Improved Asymmetrical Euler Method, that is a modification of a previously existing method. We deploy these two techniques in the Particle-in-Cell framework. In this section in particular MOLT employs a dimensional splitting algorithm, solving a set of one dimensional boundary value problems using a Green's function. This will all be done using one particular temporal discretization scheme, the first order Backward Difference Formula. Numerical results are shown to give evidence for the quality of these techniques, though it is noteworthy that the combination of this wave solver and particle pusher does not satisfy the Lorenz gauge condition, nor does it satisfy the involutions of Maxwell's equations, otherwise known as Gauss's laws.The second part of this thesis fills this lacuna, suggesting two ways for doing so. First it will consider theory to connect satisfaction of the continuity equation with satisfaction of the Lorenz gauge. It will consider in particular a way of satisfying this theory with multi-dimensional Green's functions, eschewing the dimension splitting of the first part. It will additionally consider the solution of the boundary value problems via other numerical techniques such as the Fast Fourier Transform or Finite Difference approach, ultimately choosing these for simplicity. The second approach will consider a gauge correction technique. It will be shown that both of these preserve the gauge, but the first method will additionally satisfy the involutions of Maxwell's equations. In a similar manner to the first part, it will do so using the first order Backward Difference Formula as the temporal discretization scheme. Numerical evidence will be given to support the theory developed.The third part of this thesis will generalize the theory connecting the satisfaction of the continuity equation with satisfaction of the Lorenz gauge and, in most cases, with Gauss's Laws. It will extend this theory to not only all orders of the Backward Difference Formulation, but to a family of second order time centered methods, arbitrary stage diagonally implicit Runge-Kutta methods, and all orders of Adams-Bashforth methods. In all but the diagonally implicit Runge-Kutta methods, Gauss's laws will be shown to be satisfied if the Lorenz gauge is. Once again numerical evidence will be given to support this.Finally some future projects will be suggested to capitalize on this work.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

FUEL COMPOSITION AND IGNITION SYSTEM VARIATION TO CONTROL COMBUSTION IN A RAPID COMPRESSION MACHINE

Thesis (Ph.D.)--Michigan State University. Mechanical Engineering - Doctor of Philosophy, 2025Aromatics have long been added to pump-grade gasoline to increase fuel octane number by increasing autoignition resistance. As octane number is expensive and impractical to determine, ignition delay time measurements are a promising way to understand autoignition resistance under modern engine operating conditions across equivalence ratios, with and without exhaust gas recirculation dilution. Therefore, ignition delay time measurements were used in Chapter 4 of this dissertation to understand the effect of six different aromatic additives on the autoignition resistance of a gasoline surrogate fuel between 700 K and 950 K at equivalence ratios relevant to current and next generation engines (\u3c6 = 0.6, 0.8, 1.0) and with exhaust gas recirculation dilution (0%, 15%, and 30%). The substituted phenol additives tested were p-cresol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol, which all varied in methyl group quantity and location. From the results presented, it was found that the para-substituted methyl group was most important for increasing the ignition delay time of the base fuel, and that nearby methyl groups are also beneficial. In order of the greatest to least overall lengthening effect on the gasoline surrogate\u2019s ignition delay time, the additives are: 3,4-xylenol, 2,4-xylenol, p-cresol, 3,5-xylenol, 2,5-xylenol, 2,6-xylenol.As autoignition resistance is important for appropriate combustion timing to prevent misfires and extreme pressure rise rates, the next chapters of this dissertation aimed to characterize a turbulent jet ignition system to accommodate fuels with variable autoignition resistance. Turbulent jet ignition has long been studied with high octane number fuels to reduce engine emissions and extend the lean operating limit from spark ignition operation. This is possible because turbulent jet ignition works by increasing the rate of flame propagation through the main chamber by multiple ignition points, reducing the dependence on the mixture\u2019s laminar flame speed during main chamber charge consumption. By increasing the burning rate in the main chamber, the amount of time the end gas region is held at elevated temperatures and pressures is reduced, as is the quantity of unburned fuel and oxidizer. This, in turn, delays the occurrence and severity of the peak pressure rise rate due to autoignition of the unburned reactants. To test the promise of turbulent jet ignition with high cetane number fuels, Chapter 5 and Chapter 6 present simulations and experiments in a rapid compression machine to quantify the events during successful turbulent jet ignition and identify performance metrics. F-24 jet fuel/air mixtures were studied at low-temperature intake conditions, and three distinct events during each case of turbulent jet ignition were identified: peak pre-chamber ignition pressure, main chamber jet ignition, and autoignition. The amount of fuel burned before autoignition was also determined and the peak pressure rise rate from the turbulent jet ignition system was reduced by up to 41% from cases where combustion was initiated by autoignition.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

Three Essays on the Economics of Dialysis

Thesis (Ph.D.)--Michigan State University. Economics - Doctor of Philosophy, 2025Chapter 1: Quality Disclosure and Patient Switching: Evidence from the Dialysis Industry:In 2012, the Centers for Medicare & Medicaid Services (CMS) implemented the End Stage Renal Disease Quality Incentive Program (QIP) to improve information transparency between dialysis patients and their treatment center by publishing novel quality scores. How dialysis patients respond to these new scores is unclear. This paper explores the extent to which the publication of quality scores influences patients' likelihood of switching dialysis centers, and whether the salience of these scores induces a behavioral change in patients. My findings show that patients at centers with lower quality scores are significantly more likely to switch than those at high quality centers. Specifically, patients at centers with a published score in the 10th percentile are nearly 19% (1.10 percentage points) more likely to switch than patients at centers with a published score in the 90th percentile. Furthermore, patients who learn they are at a low-quality center when scores are published increase their likelihood of switching by over 1.18 percentage points, suggesting that patients respond to the salience of quality scores. These results show that increasing transparency around treatment quality can affect patient decision-making and improve provider-patient matching, with implications for patient welfare and resource allocation. Chapter 2: Patient Preference of Provider Influence: Variation in Health Care Spending Among Dialysis Patients: Dialysis patients spend a substantial amount of time interacting with the staff and peers at their dialysis center, making these environments a potentially important influence on patient behavior. In this paper, I use patient switching to disentangle the demand- and supply-side factors that influence general health care spending. Leveraging an event study design, I examine changes in non-dialysis medical spending before and after a patient switches to a new dialysis provider, relating these changes to the utilization patterns of their new peers. The results show that switchers experience an immediate and persistent change in non-dialysis spending. Point estimates suggest that dialysis centers account for between 37.6% and 61.2% of the variation in a patient's non-dialysis health care spending. The effects are strongest in spending categories with greater patient discretion, such as non-dialysis outpatient visits, suggesting that policies aimed at reducing costs may benefit from appropriate targeting. Chapter 3: Value-Based Purchasing and Payment Reductions: Dialysis Center Response to the End Stage Renal Disease Quality Incentive Program: The Centers for Medicare & Medicaid Services introduced the End Stage Renal Disease Quality Incentive Program in 2012 to improve the quality of dialysis services and reduce costs. A key feature of this program is the implementation of value-based purchasing, which reduces reimbursement to dialysis centers that perform poorly on quality metrics. This paper evaluates whether such payment penalties are effective at improving clinical quality. Using administrative data from Medicare, I compare penalized and non-penalized dialysis centers and estimate the effect of penalties on clinical quality using three empirical approaches: a two-way fixed effects difference-in-differences model, a dynamic event study, and a model allowing treatment effect heterogeneity. The results suggest that dialysis centers penalized for low quality exhibit sustained improvements in septic infections, lower mortality rates, and fewer hospitalizations. These findings support value-based purchasing as an effective tool to incentivize improvements in treatment quality.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

Beyond a seat at the table : Investigating gender differences in leaders\u2019 strategic conversation networks

Thesis (Ph.D.)--Michigan State University. Psychology - Doctor of Philosophy, 2025Theories related to the strategic management of organizations, such as the UpperEchelons Theory (Hambrick & Mason, 1984) and the Resource-Based View (Wernerfelt, 1984), suggest that gender diversity in leadership groups can enhance organizational strategy because women will have a tangible and unique impact on strategic decision-making. However, empirical studies based on the Upper Echelons Theory and the Resource Based View have predominantly relied on demographic representation as a proxy for women\u2019s impact on strategy, assuming that the presence of women in leadership equates to their influence on strategic decision-making. Research on gender and networks would suggest that women leaders are not consistently involved in critical strategic conversations\u2014even if they are demographically represented in leadership groups. This raises an important question: Are women leaders participating in strategic conversations at the same rate as their men counterparts, or are they still on the sidelines? My dissertation addressed this question by drawing from theory and research at the intersection of gender and networks. I hypothesized that homophily tendencies, combined with the gender composition of organizations, makes women leaders (1) less likely than men to be connected with men leaders, but more likely than men to (2) reach outside of their own work groups to form connections, and (3) to form gender heterogeneous ties. In turn, the composition of women\u2019s network ties makes them less likely to occupy powerful, stable, and strong positions in strategic conversation networks. Further, I hypothesized that the extent to which leaders have connections with men leaders would be more strongly and positively associated with powerful network positions for women leaders than for men leaders. I tested my hypotheses in a sample of 673 upper- and middle-managers from 13 organizations across different industries who completed social network surveys. Results showed complex patterns. Despite women having lower network \u2018power\u2019 than men, results showed that women had significantly fewer men contacts in their strategic networks, and that such differences were unexpectedly related to increased network \u2018power\u2019 (degree centrality). The relationship between the proportion of men leader contacts and network power was more positive, but not significant for women leaders. Contrary to expectations, women also had fewer contacts outside of their immediate work groups, which led to increased network \u2018stability\u2019 (contact density). When considering the larger gender composition of each organization, having more women in organizational leadership positions or on the top management team strengthened the positive indirect effect of gender on network power through having fewer men contacts. Rather than being excluded from strategic conversations as the gender and networks literature might suggest, women appear to develop alternative networking approaches that can effectively increase their involvement in strategy networks. By moving beyond demographic representation to analyze how men and women leaders participate in strategic networks, the present dissertation offers important insights into the mechanisms that shape involvement in organizational strategy networks and women\u2019s career advancement.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

H\uc9RITAGE DE LA N\uc9GRITUDE ET D\uc9FIS D\u2019INT\uc9GRATION SOCIALE EN FRANCE DANS NOIRE N\u2019EST PAS MON M\uc9TIER (2018) DE A\ucfSSA MA\ucfGA

Thesis (M.A.)--Michigan State University. French and Francophone Studies \u2013 Master of Arts, 2025Dans l\u2019ouvrage Noire n\u2019est pas mon m\ue9tier, A\uefssa Maiga avec quinze actrices noires fran\ue7aises mettent en sc\ue8ne les exp\ue9riences qu\u2019elles ont v\ue9cues dans le milieu cin\ue9matographique fran\ue7ais, des exp\ue9riences marqu\ue9es par un racisme syst\ue9mique et une invisibilisation de leurs images. Entre pute, femme de m\ue9nage, femme sans papiers ou m\ueame la dame \ue0 l\u2019accent africain, ce t\ue9moignage collectif nous plonge au c\u153ur des pr\ue9jug\ue9s dans l\u2019attribution des r\uf4les dans le cin\ue9ma fran\ue7ais. L\u2019ouvrage souligne des th\ue8mes tels que l\u2019int\ue9gration des groupes minoritaires de France, l\u2019invisibilisation, et le racisme syst\ue9mique contre les personnes noires dans le cin\ue9ma fran\ue7ais. Faisant \ue9chos aux combats des grands penseurs de la n\ue9gritude, l\u2019un des premiers mouvements de revendication des causes noires en France, ces actrices d\ue9voilent leur ferme volont\ue9 de rompre avec les s\ue9gr\ue9gations et les st\ue9r\ue9otypes d\u2019ordre raciste dans la cin\ue9matographie fran\ue7aise. Elles sont entre autres Nad\ue8ge Beausson-Diagne, Mata Gabin, Ma\uefmouna Gueye, Eye Haidara, Rachel Khan, A\uefssa Ma\uefga, Sara Martins, Marie-Philom\ue8ne Nga, Sabine Pakora, Firmine Richard, Sonia Rolland, Magaajyia Silberfeld, Shirley Souagnon, Assa Sylla, Karidja Tour\ue9, et France Zobda \ue0 t\ue9moigner de la mani\ue8re dont la racialisation de la vie sociale, n\ue9e avec l\u2019histoire coloniale et l\u2019esclavage persistent dans leur v\ue9cu contemporain et porte atteinte \ue0 leur libert\ue9. Un si\ue8cle apr\ue8s la naissance de la N\ue9gritude, cette \ue9tude vise \ue0 analyser le racisme syst\ue9mique dans l\u2019univers cin\ue9matographique fran\ue7ais tout en mettant en avant les diff\ue9rentes voies que les seize actrices construisent empruntent vers la libert\ue9.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

FOSTERING KNOWLEDGE CO-PRODUCTION IN NATURAL RESOURCE MANAGEMENT AND INTEGRATION OF TRIBAL NATURAL RESOURCE MANAGEMENT IN FORESTRY CURRICULA

Thesis (Ph.D.)--Michigan State University. Forestry - Doctor of Philosophy, 2025An estimated 4,000 miles of Indigenous forestland share a border with US Forest Service lands alone, not including other agencies and organizations that border Indigenous lands (Dockry and Hoagland, 2017). These shared borders mean that forest management and stewardship may benefit from cross-boundary collaboration and communication. Without proper training in communicating with, understanding of, and general exposure to tribal entities, future foresters are not only at a disadvantage, but are inadequately prepared to work meaningfully with tribal partners. In addition to this, federal land managers now have a legal requirement to consult with tribes on forest management in these areas where cross-boundary stewardship is essential (Dockry & Hoag, 2017). This requirement is often difficult, because new foresters lack the background knowledge or respect for Indigenous ways of knowing (Verma et al., 2016). Outside of classes and programs specifically designed to teach about Indigenous knowledge and topics, these students and future foresters do not receive the education and training they need to work meaningfully with tribes. Few research studies have examined the prevalence of Indigenous knowledge in forestry curricula and how forestry education can incorporate Indigenous knowledge comprehensively and even fewer have explored the benefits that come with this integration and collaboration in educational settings. This collaboration can then help knowledge co-production between Indigenous and non-Indigenous natural resource managers. Knowledge co-production (KCP) is a process that requires a time investment and open-mindedness among the contributors. KCP combines Indigenous knowledge and Western science to create stronger management outcomes that address current environmental challenges facing the world (Kruijf et. al., 2020). With an increasing emphasis on KCP, particularly with underrepresented and historically marginalized communities, there is a demand placed upon communities to engage in research and knowledge co-production, by researchers and the entities that fund them. In the Great Lakes Watershed, there are 27 federally recognized tribal groups. These tribal communities are facing disproportionate impacts from climate change, such as sea-level rise and increase in intense weather changes (David-Chavez and Gavin, 2018). This work seeks to understand how tribes in the region are affected by and managing their natural resources, understanding their capacity for knowledge co-production, study capacity impacts of knowledge co-production, and if and how this knowledge is used in forestry curricula. From this study we found that the greatest concerns for tribes in the region are climate change and capacity, however there is a strong interest in knowledge co-production with some tribes already implementing some collaborative projects. We found that there are practical limitations to knowledge co-production and capacity is the central barrier. Preparing future forestry professionals to engage in meaningful knowledge co-production will not only require a deeper understanding of tribal resource management and co-stewardship approaches but may also require a fundamental shift in forestry education. A sample of U.S. undergraduate forestry curricula revealed that while there is interest in including more Indigenous knowledge in the future, most courses in forestry majors lack Indigenous knowledge inclusion. These results can help foster new conversations and changes that can encourage the inclusion of more Indigenous knowledge in forestry curricula and natural resource management more broadly.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

ABUNDANCE, DISTRIBUTION, AND PERSISTENCE OF BIRDS AND MAMMALS UNDER ENVIRONMENTAL CHANGE

Thesis (Ph.D.)--Michigan State University. Integrative Biology - Doctor of Philosophy, 2025More than one-fifth of vertebrate species are threatened with extinction. Despite global efforts to conserve biodiversity, species abundance and diversity continues to decline across taxonomic groups and geographic regions. Achieving conservation goals relies on accurate biodiversity monitoring and a deep understanding of how natural and anthropogenic factors influence individual species and communities as a unit. A key theme of my research is advancing the application of quantitative methods to determine the status and persistence of wildlife by maximizing the use of available data. To that end, my dissertation work aims to build knowledge that will help sustain biodiversity in a rapidly changing world. In chapter one, I develop a modified hierarchical distance-sampling model to estimate the abundance of hard-to-detect chimpanzees and elephants in a dense tropical forest within the Albertine Rift ecoregion in east-central Africa. The Albertine-Rift is one of the most biodiverse places in the world, supporting more than half of Africa\u2019s bird species and 40% of mammals. In situations where visibility is limited, indirect measures of species (e.g., nests, dung) serve as proxies for counts of individuals. Current approaches to estimate population abundance using indirect sign data do not adequately account for variations in sign production and spatial patterns of animal density. My model reveals a significant decline in chimpanzees, and an increase in elephants between 2007 and 2021 within the region. My modelling approach produces more precise estimates of covariate effects on animal density by maximizing the use of all the available data to account for long-term and recent variations in abundance. In chapter two, I apply a community distance sampling model to evaluate niche overlap of ecologically similar bird species within a montane tropical forest in the Albertine Rift, where elevation strongly correlates with environmental conditions (e.g., climate, forest type). Although hundreds of bird species live within the region, the underlying mechanisms that facilitate coexistence of many competing species are poorly understood. My model shows that bird species coexistence is determined primarily by abiotic factors (i.e., the environmental elevation gradient) and secondarily by biotic factors (i.e., within-habitat segregation across horizontal space and vertical forest strata). Quantifying niche overlap indices along multiple dimensions provides deep insights into community structuring and a foundation to predict species distributions in response to ongoing environmental change. In chapter three, I assess the impacts of anthropogenic threats across bird and mammal functional groups using global data collected by the International Union for Conservation of Nature. Anthropogenic threats vary in how they affect individual species, taxonomic groups, and biodiversity as a whole. My analysis identified the anthropogenic threats with the highest impacts on bird and mammal functional groups and the functional groups that are most threatened overall. Across different anthropogenic threats, I found that the most vulnerable functional groups were vertivores, aquatic predators, frugivores, and herbivores for birds, and vertivores, aquatic predators, and frugivores/nectivores/granivores for mammals. My results reveal that anthropogenic threats vary in how they affect functional diversity, offering valuable baseline information for how best to target conservation actions for vulnerable species groups. The work in my dissertation offers valuable insights on how to monitor, estimate, and predict wildlife population distributions in response to natural environmental variation and anthropogenic threats. Tracking biodiversity trends over time and space is critical to teasing apart the interacting factors that drive species abundance patterns and determining the consequences of changing environmental conditions. The models and methods in my research are transferable to other systems and taxonomic groups, offering a path forward to improved conservation planning.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

ENHANCING PLATE HEAT EXCHANGER PERFORMANCE THROUGH INNOVATIVE FIN AND HEADER DESIGNS USING CFD AND REDUCED-ORDER MODELING

Thesis (Ph.D.)--Michigan State University. Mechanical Engineering - Doctor of Philosophy, 2025Plate heat exchangers (PHEs) are extensively used in various thermal systems due to their compact designs, high heat transfer coefficients, and superior scalability compared to other heat exchanger types. However, their performance often deteriorates due to uneven fluid distribution among channels, leading to non-uniform heat transfer and increased pressure drops. Performance enhancements can be achieved through the redesign of in-plane flow structures (fins) and modifications to header configurations. This study introduces novel three-dimensional twisted S-shaped fins to enhance thermal performance and presents comprehensive reduced-order thermo-hydraulic models to investigate flow maldistribution and rapidly optimize PHE designs for various header shapes.The first part of this dissertation presents a PHE design incorporating three-dimensional twisted S-shaped fins, fabricated using additive manufacturing technology. These fins promote controlled fluid swirl and enhance heat transfer. Turbulent conjugate heat transfer simulations are conducted to assess the thermal and hydraulic performance of the proposed configurations. By systematically varying mass flow rates and fin geometries, an optimized design suitable for high-temperature, high-pressure applications is identified.The second part of the study addresses flow maldistribution in PHEs caused by suboptimal header design. Computational Fluid Dynamics (CFD) analyses are conducted on PHEs with both straight and tapered header configurations to identify the optimal header design for achieving uniform flow distribution. While the introduction of a tapered header can reduce the recirculation zone observed in straight headers, contrary to existing research, the study reveals that tapered headers can increase flow maldistribution compared to straight headers. However, these CFD analyses are computationally intensive, making it challenging to identify conditions where tapered headers are advantageous.To significantly reduce computational expenses, a reduced-order model is developed to rapidly assess the potential impact of tapered headers. This model, validated against existing research, is capable of estimating both flow distribution and pressure drop within PHEs with minimal computational resources. Key structural parameters such as header diameter, number of channels, channel area, and taper ratio are identified as critical factors influencing flow distribution. These parameters play a crucial role in determining the choice between tapered and uniform headers. One of the most significant findings is the identification of the range of \u3b6 values, representing flow resistance inside the channels, where tapered headers provide more uniform flow compared to straight headers.The predictive modeling framework is further extended to more complex header geometries, including parabolic and hyperbolic shapes, thereby advancing the understanding of fluid distribution in complex geometries and contributing to the design of more efficient, reliable, and cost-effective PHEs.Finally, a comprehensive heat transfer model developed for PHEs is integrated with the predictive model. The resulting thermo-hydraulic model incorporates the role of header configuration in flow maldistribution and constitutes a tool for selecting appropriate structural parameters. This integrated model enables rapid evaluation of the impact of flow maldistribution on the effectiveness of PHEs without extensive computational resources. Overall, this dissertation contributes a novel design framework for PHEs, supporting applications in sustainable energy systems and industrial processes.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

Evaluating Box Compression Strength (BCS) using an Artificial Neural Network (ANN)

Thesis (Ph.D.)--Michigan State University. Packaging - Doctor of Philosophy, 2025Though box compression strength (BCS) is commonly used as a performance criterion for shipping containers, the state-of-the-art BCS estimation produces results within a broad range of values. In this study we implemented a new approach, artificial neural networks (ANN), to explore how much data may be needed for an ANN to reasonably predict compression strength, and how the ANN approach performs while facing variation that adversely impacts other modeling methodologies. An ANN model can be built by comprehensively adjusting four modeling factors that interact with each other to influence model accuracy and can be optimized by minimizing model MSE. Using both data available from the literature and a \u201csynthetic\u201d data set using idealized data based on the McKee equation, we find that model estimation accuracy remains limited by the uncertainty or error in the input parameters combined with uncertainty from the ANN process itself, and we produce an estimate for this impact. The population size to build an ANN model that can reasonably estimate BCS has been identified based on different data sets in this study.Packaging design plays a crucial role in ensuring the protective performance of packages. Various factors must be considered to ensure package strength during the packaging design process. Understanding the relative importance of each influencing factor or design feature provides valuable insights for optimizing packaging material utilization. However, current methods such as testing and finite element analysis have limitations in evaluating the relative significance of these parameters. In response to these challenges, in this research, we applied different methods to comprehensively evaluate the relative importance of different packaging design features on a given packaging property. Using BCS as a representative packaging property, the relative importance of up to six BCS features (Edge Crush Test (ECT), Perimeter, Thickness, Depth, and Flexural Stiffness in both the machine and cross-machine directions) were evaluated. Four distinct ANN methods were employed - Connection weights method, Gradient-based method, Permutation method, and SHAP values. These techniques were applied to two datasets: one comprising "synthetic" data based on the McKee formula and the other representing real-world scenarios. The reliability of these methods was assessed. Different input feature importance (FI) scores obtained from the four methods have been calculated and compared with theoretical BCS FI derived from the McKee formula. The BCS feature ranking result given by the synthetic data is verified by the theoretical feature importance ranking indicated by the McKee formula. Although box depth is considered to have zero importance in the McKee formula, the BCS feature importance ranking from the real dataset highlights its significance, aligning with buckling theory. The study gives an insight into the BCS feature importance evaluation using ANN approach and guides packaging design material and cost saving. The ultimate objective of this research is to develop a comprehensive ANN model for predicting Box Compression Strength (BCS). To achieve this, we utilized a dataset encompassing a wide range of box dimensions commonly encountered in industrial applications. After applying multiple optimization methods to determine the optimal number of hidden neurons and further identifying the key factor values influencing the model, a generalized ANN model was trained. The trained ANN model can predict the BCS commonly used in the industrial applicable level with an error of 9.51%. The primary factor contributing to the high BCS error is the presence of boundary data points and the small sample size of the current data set. One possible strategy to improve ANN prediction accuracy is to continually expand the current dataset sample size using available resources. In essence, this study serves as a roadmap for forthcoming research endeavors seeking to leverage ANN techniques to tackle challenges and provide solutions within the corrugated industry.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references

Transportation Vibration Effects on Apple Bruising

Thesis (M.S.)--Michigan State University. Packaging - Master of Science, 2025Mechanical damage, particularly bruising, is a major cause of postharvest losses in fresh produce, significantly impacting fruit quality and marketability. Apples, being highly susceptible, experience external forces during handling, storage, and transportation, primarily from vibrations, impacts, and compression. This study analyzes the effects of vibration parameters (intensity and duration), truck suspension systems, apple varieties, and packaging configurations on minimizing apple bruising under realistic transportation conditions. Two apple varieties, Fuji and Jonagold, were packaged in corrugated boxes with trays, reusable plastic containers (RPCs) with trays, and volume packing systems. They were exposed to random vibration profiles based on ASTM D4169, simulating leaf-spring and air-ride suspensions at intensities 0.2, 0.3, 0.5 and 0.7 Gravity Root Mean Square (Grms) for 1, 3, and 5 hours. Additionally, a multi-layer packaging setup was tested to evaluate damage distribution across layers. Results demonstrated that vibration intensity, duration, and suspension type significantly influence bruising. Leaf-spring suspensions caused more damage than air-ride systems, especially at higher intensities and longer durations. Apples in the top layer of stacked packages experienced the most damage, while lower layers benefited from load distribution. Among packaging types, corrugated board with Hexcel wrap outperformed others, offering improved protection and recyclability. To further assess factor importance, Random Forest Regression was applied, revealing vibration intensity as the most influential factor, followed by duration, packaging type, and apple variety. These findings support the need for optimized packaging and vibration control strategies. This study highlights the importance of combining vibration testing, sustainable packaging materials, and multi-layer designs to reduce apple bruising. It also suggests the development of new ASTM/ISTA test profiles tailored to produce distribution, including multi-axis vibration testing for improved simulation accuracy.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references