Engineering Commons^™

Simulating The Effect Of Gut Microbiome On Cancer Cell Growth Using A Microfluidic Device, Ekansh Mittal, Grace Cupp, Youngbok (Abraham) Kang

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

The imbalance in the gut microbiome plays a vital role in the progression of many diseases, including cancer, due to increased inflammation in the body. Since gut microbiome-induced inflammation can serve as a novel therapeutic strategy, there is an increasing need to identify novel approaches to investigate the effect of inflammation instigated by gut microbiome on cancer cells. However, there are limited biomimetic co-culture systems that allow testing of the causal relationship of the microbiome on cancer cells. Here we developed a microfluidic chip that can simulate the interaction of the gut microbiome and cancer cells to investigate the effects …

Elucidating The Interfacial Bonding Behavior Of Over-Molded Hybrid Fiber Reinforced Polymer Composites: Experiment And Multiscale Numerical Simulation, Gideon A. Lyngdoh, Sumanta Das

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

This paper implements molecular dynamics (MD) simulation using reactive force field (ReaxFF) to evaluate the

atomistic origin of the interfacial behavior in the overmolded hybrid unidirectional continuous carbon fiber low-melt PAEK (CFR- LMPAEK)-short carbon fiber reinforced PEEK (SFR-PEEK) polymer composites. From the MD simulation, it was observed that the

interfacial properties improve with increasing maximum processing temperature and injection pressure although such an improving trajectory gets saturated beyond specific limits. The interfacial strength and fracture response of the hybrid polymer system at the interface are also evaluated. The mechanical responses obtained from MD simulation are used as adhesive properties in …

Fracture Response Of Wollastonite Fiber-Reinforced Cementitious Composites: Evaluation Using Micro-Indentation And Finite Element Simulation, Sami Doner, Gideon A. Lyngdoh, Sumeru Nayak, Sumanta Das

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

The paper presents indentation studies on wollastonite fiber incorporated cementitious systems. The acicular nature of the fibers is poised to delay the coalescence of micro-cracks in such systems thus leading to tougher building materials. Towards that end, load-penetration depth results from the indentation studies are employed to ascertain elastic and fracture properties of wollastonite-incorporated cementitious composites. While up to 10% mass-based cement-replacement by wollastonite results in comparable elastic moduli as compared to conventional binders, the fracture toughness increases by as much as 33%. In order to gain insights into the toughening mechanisms brought about by the fine fibers, a microstructure-guided …

Basketball Shooting Performance Is Maximized By Individual-Specific Optimal Release Strategies, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

This study investigated the relationship between optimal basketball release angles and individual release distributions and whether individuals seek their optimal or minimum velocity release strategy. Sixteen male basketball players (height 183 ± 9 cm, age 22.6 ± 7 years) were recorded shooting 75 three-point shots. Ball release angle and velocity estimates were used in a nonparametric kernel density estimator (KDE) to identify individual-specific release distributions and optimal release angles. Optimal releases varied among individuals and were 4.3 ± 2.1° higher than minimum velocity releases. Mean release angles were 3.9° higher than the minimum velocity angle (p < 0.001) and only 0.4° below the optimal (p = 0.5). …

Prediction Of Concrete Strengths Enabled By Missing Data Imputation And Interpretable Machine Learning, Gideon A. Lyngdoh, Mohd Zaki, N.M. Anoop Krishnan, Sumanta Das

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Machine learning (ML)-based prediction of non-linear composition-strength relationship in concretes requires a large, complete, and consistent dataset. However, the availability of such datasets is limited as the datasets often suffer from incompleteness because of missing data corresponding to different input features, which makes the development of robust ML-based predictive models challenging. Besides, as the degree of complexity in these ML models increases, the interpretation of the results becomes challenging. These interpretations of results are critical towards the development of efficient materials design strategies for enhanced materials performance. To address these challenges, this paper implements different data imputation approaches for enhanced …

Predicting The Near Field Underwater Explosion Response Of Coated Composite Cylinders Using Multiscale Simulations, Experiments, And Machine Learning, Sumeru Nayak, Gideon A. Lyngdoh, Arun Shukla, Sumanta Das

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Prediction of underwater explosion response of coated composite cylinders using machine learning (ML) requires a large, consistent, accurate, and representative dataset. However, such reliable large experimental dataset is not

readily available. Besides, the ML algorithms need to abide by the fundamental laws of physics to avoid non- physical predictions. To address these challenges, this paper synergistically integrates ML with high- throughput multiscale finite element (FE) simulations to predict the response of coated composite cylinders

subjected to nearfield underwater explosion. The simulated responses from the multiscale approach correlate very well with the experimental observations. After validation of the multiscale approach, a …

The Role Of Ball Backspin Alignment And Variability In Basketball Shooting Accuracy, Nathan Slegers, Dave Love

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Interaction between the shooting hand and ball at the moment a basketball is released generates a three dimensional backspin of the ball. This study is the first to investigate how characteristics of the backspin alignment and variability contribute to lateral shooting accuracy. Spin axis (SA) direction and backspin magnitude were measured on 25 shot attempts for 26 collegiate basketball players (male: n = 16, female: n = 10). The mean SA alignment, as viewed from the shooting hand side, was found to be tipped down and towards the target (p < 0.001). Standard deviations (SD) in the SA alignment were strong predictors of lateral accuracy (vertical SD: r = 0.80, p < 0.001, forward-backward SD: r = 0.51, p = 0.01), with variation in the vertical alignment being the best predictor. No significant correlation between mean SA misalignment and lateral accuracy was observed. However, intra-individual relationships between SA misalignment and lateral error revealed that individuals tended to have 0.17 degrees more misalignment for each cm of lateral error (p < 0.001, 95% CI: 0.24–0.09). These indicate that while an individual’s mean alignment may not predict lateral accuracy, improving one’s SA alignment and reducing alignment variability may increase lateral accuracy.

The Applications And Challenges Of The Development Of In Vitro Tumor Microenvironment Chips, Annika Johnson, Samuel Reimer, Ryan Childres, Grace Cupp, Tia C.L. Kohs, Owen J.T. Mccarty, Young Bok Abraham Kang

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

The tumor microenvironment (TME) plays a critical, yet mechanistically elusive role in tumor development and progression, as well as drug resistance. To better understand the pathophysiology of the complex TME, a reductionist approach has been employed to create in vitro microfluidic models called “tumor chips”. Herein, we review the fabrication processes, applications, and limitations of the tumor chips currently under development for use in cancer research. Tumor chips afford capabilities for real-time observation, precise control of microenvironment factors (e.g. stromal and cellular components), and application of physiologically relevant fluid shear stresses and perturbations. Applications for tumor chips include drug screening …

Array Modeling And Testing Of Fixed Owc Type Wave Energy Converters, Bret Bosma, Ted Brekken, Pedro Lomonaco, Bryony Dupont, Chris Sharp, Belinda Batten

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

If wave energy technology is to mature to commercial success, array optimization could play a key role in that process. This paper outlines physical and numerical modeling of an array of five oscillating water column wave energy converters. Numerical model simulations are compared with experimental tank test data for a non-optimal and optimal array layout. Results show a max increase of 12% in average power for regular waves, and 7% for irregular waves between the non-optimized and optimized layouts. The numerical model matches well under many conditions; however, improvement is needed to adjust for phase errors. This paper outlines the …

A System Dynamics Model Of Supply-Side Issues Influencing Beef Consumption In Nigeria, Kelechukwu G. Odoemena, Jeffrey P. Walters, Holger Maximilian Kleemann

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

The per capita consumption of beef in Nigeria is reducing amidst a rising population that is dependent on beef as a major source of animal protein. In this paper, a system dynamics (SD) model was developed with the aim of testing exploratory policies aimed at reversing this trend. The simulations of various policy tests showed that, of all the policies tested, having a higher carcass yield seems to be the most efficient solution, but its feasibility faces some steep biological and ecological challenges. However, a combination of policies that cuts across the land–cattle–market nexus is necessary to obtain a consumption …

Understanding Rural Water Services As A Complex System: An Assessment Of Key Factors As Potential Leverage Points For Improved Service Sustainability, Nicholas Valcourt, Jeffrey P. Walters, Amy Javernick-Will, Karl Linden, Betelhem Hailegiorgis

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Rural water supply services worldwide consistently fail to deliver full public health impacts as intended due to a low service sustainability. This failure is increasingly attributed to weak local systems composed of social, financial and environmental factors. Current approaches in the water, sanitation and hygiene (WASH) sector for understanding and improving these systems typically focus on the strength and capacity of these factors, but not the interactions between them. We contend that these approaches overlook the inherent complexity and context-specific nature of each local system. To assess this complexity, we conducted four participatory factor mapping workshops with local stakeholders across …

System Approaches To Water, Sanitation, And Hygiene: A Systematic Literature Review, Nicholas Valcourt, Amy Javernick-Will, Jeffrey P. Walters, Karl Linden

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Endemic issues of sustainability in the water, sanitation, and hygiene (WASH) sector have led to the rapid expansion of ‘system approaches’ for assessing the multitude of interconnected factors that affect WASH outcomes. However, the sector lacks a systematic analysis and characterization of the knowledge base for systems approaches, in particular how and where they are being implemented and what outcomes have resulted from their application. To address this need, we conducted a wide-ranging systematic literature review of systems approaches for WASH across peer-reviewed, grey, and organizational literature. Our results show a myriad of methods, scopes, and applications within the sector, …

Systematic Errors In Video Analysis, Tim Martin, Kayt E. Frisch, John Zwart

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Video analysis helps students to connect physical, mathematical, and graphical models with the phenomena that the models represent and improves student kinematic graph interpretation skills. The widespread availability of easy to use software packages like Logger Pro (Vernier), Capstone (PASCO), and Tracker have led to many introductory physics courses adopting video analysis techniques in the classroom. Such uses include high-speed cameras to study rocket launches and other innovative applications. In this paper, we will look at ways in which some common systematic errors can affect outcomes.

Agricultural Byproducts As Amendments In Bioretention Soils For Metal And Nutrient Removal, Camille Morgan, Cara Poor, Ben D. Giudice, Jacob Bibb

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

This study investigated the effectiveness of metal and nutrient removal from stormwater in bioretention systems amended with agricultural byproducts. Both batch and column studies were conducted to evaluate three amendments: hazelnut shells, pecan shells, and spent grain from the brewing process. Batch studies using buffered synthetic water containing copper and zinc evaluated adsorptive properties of the three amendments. Of the three amendments, hazelnut shells had the highest sorption coefficient based on Kd ranges of 19,200–106,000 L=kg and 8,610–18,900 L=kg for zinc and copper, respectively. Both pecan shells and spent grain had significantly lower Kd values for zinc (2,160–6,030 L=kg and …

Factors Influencing Revenue Collection For Preventative Maintenance Of Community Water Systems: A Fuzzy-Set Qualitative Comparative Analysis, Liesbet Olaerts, Jeffrey P. Walters, Karl G. Linden, Amy Javernick-Will, Adam Harvey

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

This study analyzed combinations of conditions that influence regular payments for water service in resource-limited communities. To do so, the study investigated 16 communities participating in a new preventive maintenance program in the Kamuli District of Uganda under a public–private partnership framework. First, this study identified conditions posited as important for collective payment compliance from a literature review. Then, drawing from data included in a water source report and by conducting semi-structured interviews with households and water user committees (WUC), we identified communities that were compliant with, or suspended from, preventative maintenance service payments. Through qualitative analyses of these data …

Simple Surface Modification Of Poly(Dimethylsiloxane) Via Surface Segregating Smart Polymers For Biomicrofluidics, Aslıhan Gökaltun, Young Bok Abraham Kang, Martin L. Yarmush, O. Berk Usta, Ayse Asatekin

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Poly(dimethylsiloxane) (PDMS) is likely the most popular material for microfluidic devices in lab-on-achip and other biomedical applications. However, the hydrophobicity of PDMS leads to non-specific adsorption of proteins and other molecules such as therapeutic drugs, limiting its broader use. Here, we introduce a simple method for preparing PDMS materials to improve hydrophilicity and decrease nonspecific protein adsorption while retaining cellular biocompatibility, transparency, and good mechanical properties without the need for any post-cure surface treatment. This approach utilizes smart copolymers comprised of poly(ethylene glycol) (PEG) and PDMS segments (PDMS-PEG) that, when blended with PDMS during device manufacture, spontaneously segregate to surfaces …

Modification Of Gleams For Modeling Movement Of Organic Contaminants From Land-Applied Biosolids, Ben D. Giudice, Thomas M. Young, Jacob P. Bibb

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Municipal biosolids are commonly applied to agricultural lands as fertilizer, but this also poses potential risks to groundwater and surface water quality from constituents that may be mobilized during storm events. In the present study, an existing model, Groundwater Loading Effects of Agricultural Management Systems (GLEAMS), is modified to predict the fate and transport of organic contaminants from land-applied biosolids, primarily via addition of a labile biosolids organic carbon phase distinct from soil organic carbon. While capable of simulating contaminant transport in runoff and via percolation, only the runoff portion of the model was able to be calibrated using existing …

Exploring The Challenges To Sustainable Rural Drinking Water Services In Chile, Jami Nelson-Nuñez, Jeffrey P. Walters, Denisse Charpentier

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Many countries around the world now face the dual challenges of closing the remaining gaps in access to drinking water in rural areas while further addressing the issues of equity, quality, and sustainability outlined in the new Sustainable Development Goals (SDGs). Our research explores the key factors for sustainability in rural drinking water services in Chile, an important example not only due to its success in rural water access but also because of the new directions the country is taking to achieve the SDGs. Drawing on results from a Delphi study of Chilean rural water experts, we discuss the most …

A Microfluidic Patterned Model Of Non-Alcoholic Fatty Liver Disease: Applications To Disease Progression And Zonation, Beyza Bulutoglu,, Camilo Rey-Bedón, Young Bok Abraham Kang, Safak Mert, Martin L. Yarmush, O. Berk Usta

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Non-alcoholic fatty liver disease (NAFLD) and its progressive form non-alcoholic steatohepatitis (NASH) affect 25% of the world population. NAFLD is predicted to soon become the main cause of liver morbidity and transplantation. The disease is characterized by a progressive increase of lipid accumulation in hepatocytes, which eventually induce fibrosis and inflammation, and can ultimately cause cirrhosis and hepatic carcinoma. Here, we created a patterned model of NAFLD on a chip using free fatty acid gradients to recapitulate a spectrum of disease conditions in a single continuous liver tissue. We established the NAFLD progression via quantification of intracellular lipid accumulation and …

Progressive Hypoxia-On-A-Chip: An In Vitro Oxygen Gradient Model For Capturing The Effects Of Hypoxia On Primary Hepatocytes In Health And Disease, Young Bok Abraham Kang, Jinsu Eo, Beyza Bulutoglu, Martin L. Yarmush, O. Berk Usta

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Oxygen is vital to the function of all tissues including the liver and lack of oxygen, that is, hypoxia can result in both acute and chronic injuries to the liver in vivo and ex vivo. Furthermore, a permanent oxygen gradient is naturally present along the liver sinusoid, which plays a role in the metabolic zonation and the pathophysiology of liver diseases. Accordingly, here, we introduce an in vitro microfluidic platform capable of actively creating a series of oxygen concentrations on a single continuous microtissue, ranging from normoxia to severe hypoxia. This range approximately captures both the physiologically relevant oxygen gradient …

Moving Toward Prevention: Rural Water Maintenance And Sustained Service Delivery, Caleb Cord, Jeffrey P. Walters, Harold Lockwood, Pranav Chintalapati, Amy Javernick-Will, Karl Linden

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

This paper outlines a research plan to be conducted across the Sustainable WASH Systems (SWS) Learning consortium to learn from maintenance approaches both internal and external to the partnership. It follows a study commissioned by IRC WASH and SWS which gathered information on prominent existing approaches from key informants.

System Dynamics Modelling As A Tool For Assessing Rural Water Sustainability, Pranav Chintalapati, Jeffrey P. Walters, Amy Javernick-Will, Karl Linden

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

System dynamics modelling is a tool that has been used for decades in business management and economics applications, but little focus has been applied to the WASH sector.

Specifically, this paper discusses the use of causal loop diagrams and stock flow diagrams as methods to better understand the systemic drivers affecting sustainability of rural water service delivery.

Wave Energy Converter Array Optimization: A Genetic Algorithm Approach And Minimum Separation Distance Study, Chris Sharp, Bryony Dupont

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

With the need to integrate renewable energy sources into the current energy portfolio and the proximity of power consumers to ocean coastlines, it is important to evaluate marine energy systems, specifically wave energy converters (WECs), as potential solutions for meeting electricity needs. The ability to model these systems computationally is vital to their eventual deployment. The power development, economics, grid integration requirements, operations and maintenance requirements, and ecological impacts must be understood before these devices are physically installed. However, the research area of WEC array optimization is young, and the few available results of previously implemented optimization methods are preliminary. …

Metabolic Patterning On A Chip: Towards In Vitro Liver Zonation Of Primary Rat And Human Hepatocytes, Young Bok (Abraham) Kang, Jinsu Eo, Safak Mert, Martin L. Yarmush, O. Berk Usta

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

An important number of healthy and diseased tissues shows spatial variations in their metabolic capacities across the tissue. The liver is a prime example of such heterogeneity where the gradual changes in various metabolic activities across the liver sinusoid is termed as “zonation” of the liver. Here, we introduce the Metabolic Patterning on a Chip (MPOC) platform capable of dynamically creating metabolic patterns across the length of a microchamber of liver tissue via actively enforced gradients of various metabolic modulators such as hormones and inducers. Using this platform, we were able to create continuous liver tissues of both rat and …

Factors Influencing Household Solar Adoption In Santiago, Chile, Jeffrey P. Walters, Jessica Kaminsky, Claudio Huepe

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

In Santiago, Chile, the market conditions are seemingly excellent for the household adoption of photovoltaic (PV) technology, yet the uptake is negligible. To explore this paradox, the authors conducted a Delphi study to solicit the knowledge of a panel of Chilean PV experts. These efforts yielded 26 factors—both motivations and barriers—impacting the diffusion of PV in Santiago. Of the 26, experts were in consensus on the relative importance of 21. The literature suggests that diffusion of PV technologies is influenced by complex technical, economic, and social factors. Similarly, the experts saw influence from financial, environmental, and energy supply (e.g., electrical …

A Systems Analysis Of Factors Influencing Household Solar Pv Adoption In Santiago, Chile, Jeffrey P. Walters, Jessica Kaminsky, Lawrence Gottschamer

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Societal uptake of household solar photovoltaic (PV) technology is the result of a complex and interdependent array of technical, social, political and economic factors. This novel study employs a systems lens to examine both technical and non-technical barriers to renewables, with a focus on interactions that are empirically influential on PV uptake. Using local solar expert stakeholder input into a participatory systems approach, this study provides a structural analysis of factors influencing household solar adoption. The approach is applied and assessed for household solar PV systems in Santiago, Chile, to gain insight into the interconnected factors driving technology adoption. Barriers …

Revealing Casual Pathways To Sustainable Water Service Delivering Using Fsqca, Kate E. Gasparro, Jeffrey P. Walters

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

This study aimed to build on theory and practice regarding the combinations of conditions that influence water service sustainability when external partners are involved. The study investigates 26 well projects that have been implemented in developing countries with the assistance of Engineers Without Borders-USA (EWB-USA). Using past literature on sustainable water service delivery in developing communities, emergent coding techniques with project documents, and surveys with EWB-USA team members, this study identifies a set of project conditions to conduct fuzzy-set Qualitative Comparative Analysis (fsQCA). Findings show that the presence of a water committee cannot alone account for project sustainability. Additional conditions, …

Human Liver Sinusoid On A Chip For Hepatitis B Virus Replication Study, Young Bok (Abraham) Kang, Siddhartha Rawat, Nicholas Duchemin, Michael Bouchard, Moses Noh

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

We have developed a miniature human liver (liver-sinusoid-on-a-chip) model using a dual microchannel separated by a porous membrane. Primary human hepatocytes and immortalized bovine aortic endothelial cells were co-cultured on opposite sides of a microporous membrane in a dual microchannel with continuous perfusion. Primary human hepatocytes in this system retained their polygonal morphology for up to 26 days, while hepatocytes cultured in the absence of bovine aortic endothelial cells lost their morphology within a week. In order to demonstrate the utility of our human-liver-sinusoid-on-a-chip, human hepatocytes in this system were directly infected by Hepatitis B Virus (HBV). Expression of the …

Embedding Systems Thinking Into Ewb Project Planning And Development: Assessing The Utility Of A Group Model Building Approach, Kimberly Pugel, Jeffrey P. Walters

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Amongst growing sociotechnical efforts, engineering students and professionals both in the international development sector and industry are challenged to approach projects more holistically to achieve project goals. Engineering service learning organisations must similarly adapt their technological projects to consider varying cultural and economic structures, ensuring more resilient social progress within development efforts. In practice, systems thinking approaches can be utilised to model the social, economic, political, and technological implications that influence the sustainability of an engineering project. This research assesses the utility of integrating systems thinking into Engineers Without Borders (EWB) project planning and development, thereby improving project impact and …

Utilizing Ground-Based Lidar Measurements To Aid Autonomous Airdrop Systems, Martin Cacan, Edward Scheuermann, Michael Ward, Mark Costello, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Uncertainty in atmospheric winds represents one of the primary sources of landing error in airdrop systems. In this work, a ground-based LIDAR system samples the wind field at discrete points above the target and transmits real-time data to approaching autonomous airdrop systems. In simulation and experimentation, the inclusion of a light detection and ranging (LIDAR) system showed a maximum of 40% improvement over unaided autonomous airdrop systems. Wind information nearest ground level has the largest impact on improving accuracy.