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Articles 15121 - 15150 of 39904

Full-Text Articles in Civil and Environmental Engineering

Nano-Channels Early Formation Investigation On Stainless Steel 316ti After Immersion In Molten Pb-Bi, Abu Khalid Rivai, Mardiyanto Mardiyanto, Annette Heinzel Apr 2017

Nano-Channels Early Formation Investigation On Stainless Steel 316ti After Immersion In Molten Pb-Bi, Abu Khalid Rivai, Mardiyanto Mardiyanto, Annette Heinzel

Makara Journal of Technology

Development of fuel cladding and structural materials in Pb-Bi environment, especially at high temperature, is a critical issue for the deployment of LFR (Lead alloy-cooled Fast Reactor) and ADS (Accelerator Driven Transmutation System). This is because of the corrosive characteristic of Pb-Bi to metals as constituent materials of fuel cladding and structural of the reactors. Corrosion test of a high-chromium austenitic stainless steel i.e. SS316Ti in molten Pb-Bi at 550 ºC has been carried out for about 300 hours continuously. The characterization using SEM-EDS (Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy) showed that an iron oxide as the outer …


Synthesis Of Libob Fine Powder To Increase Solubility, Etty Marti Wigayati, Titik Lestariningsih, Christin Rina Ratri, Ibrahim Purawiardi, Bambang Prihandoko Apr 2017

Synthesis Of Libob Fine Powder To Increase Solubility, Etty Marti Wigayati, Titik Lestariningsih, Christin Rina Ratri, Ibrahim Purawiardi, Bambang Prihandoko

Makara Journal of Technology

Lithium bis (oxalate) borate or LiBOB compound has captured interest of researchers, because it is potentially viable to be used as electrolyte salt in lithium-ion battery system. This compound is easy to synthesize and considered to be more environmentally friendly compared to conventional electrolyte salt because LiBOB does not contain halogen element. This research focused on the synthesis of LiBOB fine powder, which main purpose is improving LiBOB salt solubility in liquid electrolyte solution. This will aid the ion transfer between electrodes which in turn will increase the electrolyte performance. Solid state reaction was employed in this experiment. Synthesis of …


Influence Of Polyethylene Glycol (Peg) In Cmc-Nh4br Based Polymer Electrolytes: Conductivity And Electrical Study, Nur Khalidah Zainuddin, Ahmad Salihin Samsudin Apr 2017

Influence Of Polyethylene Glycol (Peg) In Cmc-Nh4br Based Polymer Electrolytes: Conductivity And Electrical Study, Nur Khalidah Zainuddin, Ahmad Salihin Samsudin

Makara Journal of Technology

The present work was carried with new type and promising polymer electrolytes system by development of carboxyl methylcellulose (CMC) doped NH4Br and plasticized with polyethylene glycol (PEG). The sample was successfully prepared via solution casting with no separation phase and good mechanical properties. The electrical conductivity and thermal conductivity of CMC-NH4Br-PEG based PEs system have been measured by the electrical impedance spectroscopy method in the temperature range of 303–373 K. The highest ionic conductivity gained is 2.48 x 10-3 Scm-1 at ambient temperature for sample contain with 8 wt. % PEG. It can be concluded that the plasticized is accountable …


Purification Simulation With Vapor Permeation And Distillation-Adsorption In Bioethanol Plant, Misri Gozan, Mia Sari Setiawan, Kenny Lischer Apr 2017

Purification Simulation With Vapor Permeation And Distillation-Adsorption In Bioethanol Plant, Misri Gozan, Mia Sari Setiawan, Kenny Lischer

Makara Journal of Technology

High purity of Bioethanol is required in biofuel mixing with gasoline (EXX). In bioethanol production line, the azeotropic property of ethanol-water becomes the barrier for purification process. This study examined two bioethanol separation processes by support of simulation tools, Superpro Designer 9.0 software. Ethanol purity and a low costeconomical process were the major considerations. Purification method of vapor permeation membrane technology was compared with distillation-adsorption method. Data from previous lab experiments and some literatures were used. The results showed that distillation-adsorption method is more economical compared to vapor permeation technology. Payback period of the simulation is 3.9 years and 4.3 …


Impact-Resistant Behavior Of Reinforced Concrete Bridge Columns, Chen Fang Apr 2017

Impact-Resistant Behavior Of Reinforced Concrete Bridge Columns, Chen Fang

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The damage caused by a vehicle collision on a pier column can be catastrophic for the functionality of a bridge, even a total collapse of the bridge. ❖ A vehicle collision and a subsequent vehicle blast cause more damages on the bridge. ❖ Limited researches have been conducted to investigate the behavior of the bridge subjected to the combined effect of vehicle collision and blast. ❖ It is necessary to analyze the responses of the bridge under the vehicle collision and blast and provide some design suggestions to strengthen the bridge.

Conclusions ❖ The finite element models including column, pile …


Optimizing Steel Railway Truss Bridge Health Monitoring, Ahmed Rageh, Daniel Linzell Apr 2017

Optimizing Steel Railway Truss Bridge Health Monitoring, Ahmed Rageh, Daniel Linzell

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Problems - Steel Railway Trusses • Aging • Large system – bridge AND railway • Labor intensive condition eval • Reported conditions: Stringer-to-floor beam connections [Haghani 2012] Stringer flange clip angle cracks [Haghani 2012] Unequal eyebars stress distribution [DelGrego 2008] Displaced eyebar pins [DelGrego 2008

Problems – Condition Evaluation • Visual inspection: Prescribed frequency Costly Subjected to human interpretation • Sensors: Focused on a single bridge Extensive array Costly


Influence Of Skew And Nonlinear Deck On Elastic Versus Inelastic Distribution Behavior And Ultimate Capacity Of Steel Girder Bridges, Fayaz Sofi, Joshua Steelman Apr 2017

Influence Of Skew And Nonlinear Deck On Elastic Versus Inelastic Distribution Behavior And Ultimate Capacity Of Steel Girder Bridges, Fayaz Sofi, Joshua Steelman

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Research Objectives

• Assessment of alternative load distribution methodologies for potential discrepancies that arise when evaluating distribution behavior of skewed steel girder bridges.

• Investigate the influence of skew and material nonlinearities (concrete cracking and steel yielding) on

• Load distribution behavior (elastic versus inelastic).

• System capacities (yielding and ultimate).

Summary and Conclusions • Influence of skew was examined on load distribution behavior, and nonlinear system-based capacities (yielding and ultimate) of composite steel girder bridges in presence of full material nonlinearities. In addition, assessment of two general definitions (beam-line and response fraction approaches) for quantifying load distribution behavior was …


Hyperelastic Structural Fuses For Steel Buildings, Francys López Apr 2017

Hyperelastic Structural Fuses For Steel Buildings, Francys López

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Why to upgrade traditional systems?

The FEMA P-58-1 listed some of the limitations in present-generation procedures:

Questions regarding the accuracy and reliability of available analytical procedures in predicting actual building response.

“High” level of conservatism underlying the acceptance criteria.

Inability to reliably and economically apply performance-based procedures to the design of new buildings; and Lack of alternative ways of communicating performance to stakeholders that is more meaningful and useful for decision making purposes.

Performance based design (PBD) emerges as the methodology aiming to bridge this gap, raising the design level performance from life safety (traditional systems) to keep structures fully …


Design For An Aging Population, Trygve Faste, Kiersten Muenchinger Apr 2017

Design For An Aging Population, Trygve Faste, Kiersten Muenchinger

TREC Final Reports

Older Americans are increasing in numbers and addressing their needs through better public transportation design will improve their quality of life. This study sought to increase understanding of the obstacles faced by people with impairments in vision, hearing and/or mobility, which are common issues for older people, and generate physical product solutions. The research was conducted to conceptualize products, structures and services to reduce or eliminate these obstacles.

With a focus on the Eugene, OR, public bus system, elderly riders were surveyed and interviewed. Designers rode on buses noting what worked well and where problems arose. Five ride-along observations of …


The Professional Constructor, Full Issue, Volume 42, Number 01 Apr 2017

The Professional Constructor, Full Issue, Volume 42, Number 01

The Professional Constructor

No abstract provided.


Ballistic Limit Equations For Non-Aluminum Projectiles Impacting Dual-Wall Spacecraft Systems, William P. Schonberg, J. Martin Ratliff Apr 2017

Ballistic Limit Equations For Non-Aluminum Projectiles Impacting Dual-Wall Spacecraft Systems, William P. Schonberg, J. Martin Ratliff

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

One of the primary design considerations of earth-orbiting spacecraft is the mitigation of the damage that might occur from an on-orbit MMOD impact. Traditional damage-resistant design consists of a 'bumper' that is placed a small distance away from a spacecraft component or from the wall of the element in which it is housed. The performance of such a multi-wall structural element is typically characterized by its ballistic limit equation (BLE), which defines the threshold particle size that results in a failure of the spacecraft element. BLEs are also key components of any micro-meteoroid/orbital debris (MMOD) risk assessment calculations. However, these …


Studies Of Hypervelocity Impact Phenomena As Applied To The Protection Of Spacecraft Operating In The Mmod Environment, William P. Schonberg Apr 2017

Studies Of Hypervelocity Impact Phenomena As Applied To The Protection Of Spacecraft Operating In The Mmod Environment, William P. Schonberg

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In keeping with the tradition of the Hypervelocity Impact Society, this paper is a written version of the keynote address I presented at the start of 2015 Hypervelocity Impact Symposium as the recipient of the Society's Distinguished Scientist Award. It covers the highlights of my nearly 30 year career working in the area of hypervelocity impact phenomenology, mainly as it is applied to the protection of humans and spacecraft that work an operate in the micrometeoroid and orbital debris (MMOD) environment.


Woodchip Denitrification Bioreactor For Reducing Nitrate In Contaminated Well Water For St. Francis Retreat Center, Andrew Highlander, Patrick Johnson Apr 2017

Woodchip Denitrification Bioreactor For Reducing Nitrate In Contaminated Well Water For St. Francis Retreat Center, Andrew Highlander, Patrick Johnson

Civil, Environmental and Sustainable Engineering Senior Theses

The St. Francis Retreat Center, which serves over 7000 people each year, has had issues with the health of Flint Lake, located on their property, during the drought season. By utilizing a nearby water well, the retreat center looks to recharge the lake and sustain its water levels, essentially restoring its natural ecosystem. The issue is that the well water is contaminated with high amounts of nitrates, which is not only an issue for the lake’s health, but also is very unsafe for human consumption. In order to design a water treatment system that is ecofriendly, sustainable, and cost-efficient, the …


Decentralized Wastewater Treatment Plant In Bangalore, India, Cameron Akhavan, Simon Barbe, Alejandro Fernandez Fernandez Apr 2017

Decentralized Wastewater Treatment Plant In Bangalore, India, Cameron Akhavan, Simon Barbe, Alejandro Fernandez Fernandez

Civil, Environmental and Sustainable Engineering Senior Theses

The Vrishabawathi River in Bangalore, India, has high levels of pollution due to untreated wastewater discharges from the city. The city requires significant expansion of its wastewater treatment infrastructure. Smaller-capacity plants spread throughout the city, known as decentralized treatment plants, provide an alternative to centralized treatment plants that can meet these demands. This project involved the design of one decentralized plant. This plant is located in the Kengeri district of the city, a mostly residential area in the outskirts of Bangalore. The designed treatment facility includes two primary clarifiers, two biotowers, and two secondary clarifiers. Plants like these can help …


Behavior And Strength Of Rc Spandrel Members Under Unsymmetrical Bending And Torsion Including Cfrp Retrofitting, Muhammad Fahim Apr 2017

Behavior And Strength Of Rc Spandrel Members Under Unsymmetrical Bending And Torsion Including Cfrp Retrofitting, Muhammad Fahim

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents the outcome of an experimental and theoretical investigation of the behavior and strength of reinforced concrete spandrel members both with and without carbon fiber reinforced polymer (CFRP) retrofitting. Both isolated spandrel members with L-shaped cross section as well as those integrated with reinforced concrete slabs are studied. A series of isolated spandrel members were tested under separate and combined actions of unsymmetrical bending and torsion. Six of these specimens were retrofitted externally with high-strength CFRP strips. Materially nonlinear analysis procedures are also formulated and programmed for the spandrel members with and without CFRP retrofitting. Furthermore, ultimate bending-torsion …


Using Lidar Data To Analyze Access Management Criteria In Utah, Marlee Lyn Seat Apr 2017

Using Lidar Data To Analyze Access Management Criteria In Utah, Marlee Lyn Seat

Theses and Dissertations

The Utah Department of Transportation (UDOT) has completed a Light Detection and Ranging (LiDAR) data inventory that includes access locations across the UDOT network. The new data are anticipated to be extremely useful in better defining safety and in completing a systemwide analysis of locations where safety could be improved, or where safety has been improved across the state. The Department of Civil and Environmental Engineering at Brigham Young University (BYU) has worked with the new data to perform a safety analysis of the state related to access management, particularly related to driveway spacing and raised medians. The primary objective …


Behavior And Strength Of Non-Prestressed And Prestressed Hillman Composite Beam Including Cfrp Retrofitting, Wajid Khan Apr 2017

Behavior And Strength Of Non-Prestressed And Prestressed Hillman Composite Beam Including Cfrp Retrofitting, Wajid Khan

Civil & Environmental Engineering Theses & Dissertations

The Hillman Composite Beam (HCB) is a recent innovation used for the first time in 2008 for a bridge construction in USA. It essentially consists of an FRP outer shell, concrete arch inside the shell and steel strands used to tie the two ends of the arch. Being new in the field, the behavior of HCB has not been thoroughly studied. This dissertation presents a study of the flexural behavior and strength of HCB up to the collapse as well as explores the influence of using carbon reinforced polymer (CFRP) retrofitting and prestressed steel for a further increase in HCB …


Hydrologic Response Caused By Wetland Expansion At Huntley Meadows Park In Hybla Valley, Virginia, Stephen Fraser Stone Apr 2017

Hydrologic Response Caused By Wetland Expansion At Huntley Meadows Park In Hybla Valley, Virginia, Stephen Fraser Stone

OES Theses and Dissertations

The goal of this study was to understand the effects of wetland expansion across a watershed. The 2013 restoration and expansion of the wetlands at Huntley Meadows Park (Fairfax County, VA) performed by Wetland Studies and Solutions, Inc. provided the opportunity to study this process. The 630 ha park contains more than 364 ha of freshwater emergent and freshwater forested wetlands. The restoration and expansion project used a subsurface vinyl-piling dam that impedes groundwater flow leaving the wetland, thus expanding the existing pond and the surrounding wetland.

This study used a network of more than twenty monitoring instruments making observations …


Quantifying Cyanide Inhibition Of Nitrification And Developing Cost-Effective Treatment Processes, Germano M. Salazar-Benites Apr 2017

Quantifying Cyanide Inhibition Of Nitrification And Developing Cost-Effective Treatment Processes, Germano M. Salazar-Benites

Civil & Environmental Engineering Theses & Dissertations

All wastewater treatment plants that operate multiple hearth furnaces (MHF) and are required to nitrify must manage the inhibitory effects of free cyanide (HCN, CN-) in the scrubber return flows due to inhibitory impacts on nitrifying bacteria.

HRSD Boat Harbor Treatment Plant (BHTP) a 25 MGD facility consisting of primary and secondary treatment, employs an anoxic selector process for nitrification and partial denitrification and operates a MHF. There is a desire to improve TN removal performance at BHTP due to an annual mass-based bubble permit limit on a combined discharge from seven HRSD plants, and there are no discharge limitations …


A Household Daily Non-Mandatory Activity Participation And Duration Modeling Accounting For Person Level Budget Constraints, Ivana Vukovic Apr 2017

A Household Daily Non-Mandatory Activity Participation And Duration Modeling Accounting For Person Level Budget Constraints, Ivana Vukovic

Civil & Environmental Engineering Theses & Dissertations

A key methodological and behavioral innovative component in recent Activity-Based Models (ABMs) used for transportation planning is the household-level non-mandatory activity participation component. While traditional ABMs use a series of simple models to predict non-mandatory activity participation decisions in a sequential manner (which is often not correct), the Multiple Discrete Continuous Extreme Value (MDCEV) model can model both individual and joint non-mandatory activity participation and time allocation decisions in different out-of-home activities of all household members simultaneously. A key advantage of the MDCEV framework is that it accounts for complex intra-household interactions among different household members by allocating the total …


15-09 Impact Of Access Management Practices To Pedestrian Safety, Deo Chimba, Henry Ajieh Mar 2017

15-09 Impact Of Access Management Practices To Pedestrian Safety, Deo Chimba, Henry Ajieh

Transportation Research Center Reports

This study focused on the impact of access management practices to the safety of pedestrians. Some of the access management practices considered to impact pedestrian safety included limiting direct access to and from major streets, locating signals, limiting the number of conflict points and separating conflict areas, removing turning vehicles from through traffic lanes, using nontraversable medians to manage left-turn movements and providing a supporting street and circulation system. The study evaluated through statistical modeling the correlation between access management practices to pedestrian crashes. Focused on the impacts of access management on pedestrian crashes, eight (8) major roadway corridors were …


Study Of Vibration For Detection And Recognition Of Concealed Machinery Within Buildings, Sushil Ghimire Mar 2017

Study Of Vibration For Detection And Recognition Of Concealed Machinery Within Buildings, Sushil Ghimire

Civil Engineering ETDs

Recently international concern about nuclear proliferation has rapidly increased. Some governmental agencies have an interest in remotely detecting and recognizing concealed machinery within buildings to detect any anomalous activity occurring inside the building.

The vibration studies of the roof and the exhaust structures of an existing utility building, the Ford Utility Center at the University of New Mexico and a simplified laboratory structure representing an industrial building, called the doghouse are presented in this thesis. The vibration studies presented allow the reader to understand to what extent it is possible to identify machines concealed within a building.

To identify machines …


Influence Of Internal Variability On Population Exposure To Hydroclimatic Changes, Justin S. Mankin, Daniel Viviroli, Mesfin Mekonnen, Arjen Y. Hoekstra, Radley M. Horton, Jason E. Smerdon, Noah S. Diffenbaugh Mar 2017

Influence Of Internal Variability On Population Exposure To Hydroclimatic Changes, Justin S. Mankin, Daniel Viviroli, Mesfin Mekonnen, Arjen Y. Hoekstra, Radley M. Horton, Jason E. Smerdon, Noah S. Diffenbaugh

Daugherty Water for Food Global Institute: Faculty Publications

Future freshwater supply, human water demand, and people’s exposure to water stress are subject to multiple sources of uncertainty, including unknown future pathways of fossil fuel and water consumption, and ‘irreducible’ uncertainty arising from internal climate system variability. Such internal variability can conceal forced hydroclimatic changes on multi-decadal timescales and near-continental spatial-scales. Using three projections of population growth, a large ensemble from a single Earth system model, and assuming stationary per capita water consumption, we quantify the likelihoods of future population exposure to increased hydroclimatic deficits, which we define as the average duration and magnitude by which evapotranspiration exceeds precipitation …


Modeling The Movement Of Septic Water Chloride Through A Soil Profile, Shawkat Kochary, Tom Byl, Bahzad Noori Mar 2017

Modeling The Movement Of Septic Water Chloride Through A Soil Profile, Shawkat Kochary, Tom Byl, Bahzad Noori

Civil and Architectural Engineering Faculty Research

The purpose of this study was to investigate the movement of chloride through a vadose zone located under failed and non-regulated septic tanks of Duhok city, Kurdistan of Iraq, potentially contaminating its groundwater. A physical vadose model (PVM) of a vertical flow direction was built in the laboratory to represent the city soil profile. The size of the PVM was 210 × 122 × 9.7 cm (height, width, and depth). Preliminary soil tests were conducted to better represent the lithology of study area. The PVM was then packed with regional silt clay soil, after modifying its texture, using an innovative …


Mechanism Of Cathodic Prevention Of Carbon Steel In Concrete, Krittin Rattakham Mar 2017

Mechanism Of Cathodic Prevention Of Carbon Steel In Concrete, Krittin Rattakham

USF Tampa Graduate Theses and Dissertations

In this work, I aim to clarify the mechanism that allows steel to attain higher chloride threshold as it is cathodically polarized. Specifically, I seek to provide empirical information on whether an intrinsic (predominantly interfacial effects of polarization) or an extrinsic (predominantly concentration changes due to polarization) mechanism may be dominant in the beneficial effect of polarization. I carried out this experiment with 12 identical concrete specimens, each with a cast-in steel plate, constantly exposed them to high-chloride environment. The specimens were divided into 4 triplicates and polarized at 4 different level from OCP, -200, -300 to -400 mVSCE …


The Impacts Of Climate Change And Anthropogenic Processes On Permafrost Soils And Usaf Infrastructure Within Northern Tier Bases, Alexander J. Graboski Mar 2017

The Impacts Of Climate Change And Anthropogenic Processes On Permafrost Soils And Usaf Infrastructure Within Northern Tier Bases, Alexander J. Graboski

Theses and Dissertations

The Department of Defense is planning over $552M in military construction on Eielson Air Force Base within the next three fiscal years. Although many studies have been conducted on permafrost and climate change, the future of our climate as well as any impacts on permafrost soils, remains unclear. This research focused on future climate predictions to determine likely scenarios for the United States Air Force’s Strategic Planners to consider. The most recent 2013 International Panel on Climate Change report predicts a 2.2ºC to 7.8ºC temperature rise in Arctic regions by the end of the 21st Century in the Representative Concentration …


United States Air Force Unaccompanied Housing Divestiture: An Economic Analysis, Dustin L. Gooden Mar 2017

United States Air Force Unaccompanied Housing Divestiture: An Economic Analysis, Dustin L. Gooden

Theses and Dissertations

The objective of this research is to determine potential cost savings associated with Air Force unaccompanied housing divestiture. This research uses Air Education and Training Command (AETC) installations as the data sample for the analysis, and will analyze the status quo, privatization, and identical FSRM options. With 16% of Air Force unaccompanied housing currently rated at various levels of inadequacy and the PRV for the inadequate housing at $2,315,773,149.00, the costs associated with renovating the inadequate unaccompanied housing is substantial. Moreover, the inadequacy of unaccompanied housing is part of the Air Force’s acceptance of risk in facilities and infrastructure to …


Adsorption Of Perfluorinated Compounds From Post-Emergency Response Wastewater, Christopher T. Schmidt Mar 2017

Adsorption Of Perfluorinated Compounds From Post-Emergency Response Wastewater, Christopher T. Schmidt

Theses and Dissertations

This research investigated the efficacy of granular activated carbon (GAC) as a method to treat water impacted with aqueous film forming foam (AFFF) after a firefighting response. Bench-top experiments were conducted and compared to field scale adsorber performance removing mg/L concentrations of PFAS in water contaminated with Military Specification AFFF. Batch tests compared four adsorbents, and determined Calgon F600 GAC and Rembind Plus mixed carbon media had the greatest perfluorooctane sulfonate (PFOS) capacities. Additional batch isotherm experiments using AFFF and higher PFOS concentrations (mg/L) indicated larger amounts of GAC are required (>30mg/L) for effective removal. Full-scale testing simulated an …


An Empirical Analysis Of Air Force Military Construction Project Delivery Method Performance In The United States, Erich C. Kramer Mar 2017

An Empirical Analysis Of Air Force Military Construction Project Delivery Method Performance In The United States, Erich C. Kramer

Theses and Dissertations

The objective of this study is to investigate the performance of the design-bid-build and design-build project delivery methods in Air Force military construction (MILCON). Project delivery performance is measured through quantitative cost, schedule, and change order metrics for 264 design-bid-build and 316 design-build MILCON projects from 2003-2014. The average response measures were statistically compared within each delivery method using three independent variables: time, facility type, and major command (MAJCOM). The historical analysis revealed that the current working estimate programmed amount ratios improved over time for design-build projects, and an overall consistency in schedule growth and project duration performance occurred across …


Toxicological Differences Between Perfluoroalkyl Substances (Pfas) Isomers Using Developmental Biomarkers, Gabriel A. Cantu Mar 2017

Toxicological Differences Between Perfluoroalkyl Substances (Pfas) Isomers Using Developmental Biomarkers, Gabriel A. Cantu

Theses and Dissertations

Perfluoroalkyl substances (PFAS) are metabolically stable synthetic chemicals that have been manufactured for commercial and industrial purposes since the 1950s. PFAS possess surfactant properties that make them ideal to fight hydrocarbon fires and are therefore present in aqueous film forming foams (AFFF). Furthermore, AFFF may contain blends of both linear and branched PFAS isomers. Research suggests that branched PFAS isomers have greater relative placental transfer efficiencies than their linear counterpart, but few studies have evaluated their toxicity. Therefore, the sustained use of AFFF in the U.S. Air Force presents a risk of branched PFAS exposures in pregnant females. This study …