Engineering Commons^™

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.