Engineering Commons^™

Friction Of Soft Elastomeric Surfaces With A Defect, Charles J. Rand, Alfred Crosby

Alfred Crosby

We consider a simple problem that provides insight into the building blocks of friction for topographically patternedsurfaces and fundamental understanding into the general friction of coatings. The problem focuses on the effect of a line defect, such as a pattern’s edge, on the lateral force of a sliding soft interface. The line defect presents a discontinuity in the stress at the sliding interface, changing the lateral stiffness and decreasing the sliding force. We relate the decrease in sliding shear force to the changes in lateral stiffness through relationships that account for contact splitting and lateral confinement effects.

Burrowing In Marine Muds By Crack Propagation: Kinematics And Forces, Sanjay Raja Arwade, Kelly M. Dorgan, Peter A. Jumars

Sanjay Raja Arwade

The polychaete Nereis virens burrows through muddy sediments by exerting dorsoventral forces against the walls of its tongue-depressor-shaped burrow to extend an oblate hemispheroidal crack. Stress is concentrated at the crack tip, which extends when the stress intensity factor (KI) exceeds the critical stress intensity factor (KIc). Relevant forces were measured in gelatin, an analog for elastic muds, by photoelastic stress analysis, and were 0.015±0.001 N (mean ± s.d.; N=5). Measured elastic moduli (E) for gelatin and sediment were used in finite element models to convert the forces in gelatin to those required in muds to maintain the same body …

Developing A Statement Of Values, William J. Frey, Jose A. Cruz-Cruz

Ethics in Science and Engineering National Clearinghouse

This module serves two purposes. First, it reports on a successful effort by the College of Business Administration of the University of Puerto Rico at Mayaguez to design and implement a statement of values in response to AACSB requirements. Second, it provides students in occupational and professional ethics courses with a series of exercises designed to teach them about codes of ethics and statements of values.

Abstract by author.

Crumpled Surface Structures, Douglas P. Holmes, Michal Ursiny, Alfred Crosby

Alfred Crosby

We present a scalable patterning method based on surface plate buckling, or crumpling, to generate a variety of topographies that can dynamically change shape and aspect ratio in response to stimuli.

Delay And Energy Tradeoff In Multi-State Wireless Sensor Networks, W. L. Leow, H. Pishro-Nik, Daiheng Ni

Daiheng Ni

This paper discusses a first attempt to investigate, using analytic means, the transmission delay and energy char- acteristics of a multi-state wireless sensor network. For such a network with n nodes, where each node can be active, resting or sleeping, a model that describes the transition of a node from one state to another and the probability associated with each state is proposed. Asymptotic analyses of transmission delay and energy are presented. We report the presence of a threshold for the arrival rate of data packets that decides which energy component dominates. The transmission delay-energy tradeoff is presented for the …

Development Of A Prototype Intersection Collision Avoidance System Under Vii, Daiheng Ni, Hossein Pishro-Nik, Richa Prasad, Mohammed Raza Kanjee, Hui Zhu, Thai Nguyen

Daiheng Ni

Vehicle collisions at in tersections account for a large percen tage of overall traffic accidents, a good portion of which are fatal. A large number of these accidents can be avoided by a warning system which makes a driver aware of potential collisions on the road, thus allowing the driver enough time to preven t such situations. This pape r presents the design of a prototype intersection collision warning system based on Vehicle Infrastructure Integration (VII). Underlying the system are wireless communications, positioning technology, and information technology that ensure accu rate and timely safety information.

Self-Assembly Of Nanoparticles At Interfaces, Alexander Böker, Jinbo He, Thomas P. Russell, Todd S. Emrick

Todd S. Emrick

Developments in the assembly of nanoparticles at liquid–liquid interfaces are reviewed where the assemblies can be controlled by tuning the size of the nanoparticles and the chemical characteristics of the ligands. Both synthetic and biological nanoparticles are discussed. By controlling the type of ligands, uniform and Janus-type nanoparticles can be produced where, at liquid–liquid interfaces, subsequent reactions of the ligands can be used to generate crosslinked sheets of nanoparticles at the interface that have applications including novel encapsulants, filtration devices with well-defined porosities, and controlled release materials. By controlling the size and volume fraction of the nanoparticles and the chemical …

Cation Exchange In Glacial Till Subjected To Highway Deicing Agent Infiltration, Niki Kallergis

Environmental & Water Resources Engineering Masters Projects

The site studied in this research project is owned by the Massachusetts Highway Department and has been used as a storage facility since the 1960's. The area has been characterized as a drumlin of glacial till composition. Improper storage practices occulTed during two decades (1960's - 1980's) by stockpiling deicing agents outdoors. Previous investigations verify groundwater contamination due to brine infiltration and establish several properties of the soil and the aquifer hydraulics. The chloride ion is unreactive and transported with groundwater molecules; however, field data and theory suggest that dissolved sodium partakes in cation exchange with sorbed cations on clay …

Modeling Fate And Transport Of Fecal Coliform In Wachusett Reservoir, Thomas P. Matthews

Environmental & Water Resources Engineering Masters Projects

The Wachusett Reservoir, located in central Massachusetts is an unfiltered, ozonated / chloraminated drinking water supply which serves 2.3 million customers in Boston, Massachusetts and surrounding communities. The Massachusetts Department of Conservation and Recreation (DCR) is responsible for managing and protecting the Wachusett Reservoir and surrounding watershed. The Massachusetts Water Resources Authority (MWRA) operates the water supply system and the Carroll Water Treatment Plant (CWTP). In addition, DCR manages and maintains the Quabbin Reservoir and watershed located in western Massachusetts. The Wachusett and Quabbin Reservoirs provide high quality water to consumers due to pristine watersheds and long hydraulic retention time. …

The Use Of Numerical Modeling Techniques To Optimize Groundwater Withdrawls And Minimize Streamflow Depletion, Yamen Hoque

Environmental & Water Resources Engineering Masters Projects

Groundwater reserves can be a valuable resource in alleviating rising water demands worldwide. The groundwater is generally pumped out of surficial aquifers using withdrawal wells. However, unregulated groundwater withdrawals can impact the flow in nearby streams negatively, causing streamflow depletions. This can hinder the ecological balance of streams and endanger the aquatic life fonTIs that call such streams home. Therefore, groundwater withdrawals must be carried out using a well managed withdrawal strategy. Rhode Island has a growing annual water demand that has been projected to exceed current supply in parts of the state by 2020. As a result, several new …

The Use Of Numerical Modeling Techniques To Optimize Groundwater Withdrawls And Minimize Streamflow Depletion, Yamen M. Hoque

Environmental & Water Resources Engineering Masters Projects

Groundwater reserves can be a valuable resource in alleviating rising water demands worldwide. The groundwater is generally pumped out of surficial aquifers using withdrawal wells. However, unregulated groundwater withdrawals can impact the flow in nearby streams negatively, causing streamflow depletions. This can hinder the ecological balance of streams and endanger the aquatic life fonTIs that call such streams home. Therefore, groundwater withdrawals must be carried out using a well managed withdrawal strategy. Rhode Island has a growing annual water demand that has been projected to exceed current supply in parts of the state by 2020. As a result, several new …

Evaluation Of Nutrients Along The Blackstone River, Megan M. Patterson

Environmental & Water Resources Engineering Masters Projects

The University of Massachusetts Blackstone River Water Quality Study was conducted in August of 2005 through November of 2006. Water quality was monitored throughout two dry weather events and five wet weather events along the Blackstone at over 20 sites from the headwaters downstream to Woonsocket, Rhode Island. Special emphasis was placed on the analysis of the nutrient loadings crossing the Massachusetts/Rhode Island state border. Continuous nitrate and phosphate readings were collected at the state line using MicroLABs. The MicroLAB results required a high degree of data adjustment; duplicate samples are recommended to ensure future data quality. Data from events …

Ground Water Management, Gwm, Formulations To Control Subsidence In A Large Scale Transient Problem, Gemma Baro-Montes

Environmental & Water Resources Engineering Masters Projects

The objective of this study is to test different formations with a new optimization program. The area under study is located close to Los Angeles, and it has experienced a large drawdown of the water table, with related subsidence. The analyses utilizes Ground Water Management (GWM), a public domain code distributed by the USGS as a process within MODFLOW 2000. The different algorithms within GWM were tested with a large-scale transient unconfined system. The different analysis allowed the verification of the program. In this application, GWM is used to optimize the resources, and the MODFLOW packages from the LANOPT Model …

Forty-Fifth Annual Allerton Conference On Communication, Control, And Computing, H. Pishro-Nik, A. Ganz, Daiheng Ni

Daiheng Ni

This paper initiates the study of scaling laws for vehicular ad hoc networks (VANET)s. It provides a general framework to study VANETs. The fundamental capacity limits of these networks are investigated and we show how the road geometry affects this capacity. The VANET capacity is calculated for different road structures. The need for new capacity metrics is dis- cussed. These results are obtained by combining geomet- rical analysis, network flow arguments, and probabilistic study of VANETs.

America Competes Act, United States

Ethics in Science and Engineering National Clearinghouse

The full text of the America COMPETES Act. See Sec. 7008. Postdoctoral Research Fellows, and Sec. 7009. Responsible Conduct of Research.

Genome-Scale Analysis Of Saccharomyces Cerevisiae Metabolism And Ethanol Production In Fed-Batch Culture, Radhakrishnan Mahadevan, Michael A. Henson

Michael A Henson

A dynamic flux balance model based on a genome-scale metabolic network reconstruction is developed for in silico analysis of Saccharomyces cerevisiae metabolism and ethanol production in fed-batch culture. Metabolic engineering strategies previously identified for their enhanced steady-state biomass and/or ethanol yields are evaluated for fed-batch performance in glucose and glucose/xylose media. Dynamic analysis is shown to provide a single quantitative measure of fed-batch ethanol productivity that explicitly handles the possible tradeoff between the biomass and ethanol yields. Productivity optimization conducted to rank achievable fed-batch performance demonstrates that the genetic manipulation strategy and the fed-batch operating policy should be considered simultaneously. …

Treatment Of Domestic Wastewater Using An Anaerobic Membrane Bioreactor: Performance And Characterization, Joseph C. Fermanian

Environmental & Water Resources Engineering Masters Projects

Anaerobic wastewater treatment has many advantages over aerobic treatment, however, factors that limit its application are the relatively high concentration of soluble organic matter in the effluent and poor settling characteristics of anaerobic sludge. Membrane filtration provides exceptional solids removal and biomass retention that can improve the biological treatment process as has been seen with aerobic MBR. The application of anaerobic processes and anaerobic membrane bioreactors (AnMBR) has been limited primarily to industrial wastewaters. The use of AnMBR in treating domestic wastewater is of great interest; however, it has not been studied sufficiently to implement on a large scale commercial …

Evaluation And Optimization Of A Pcr Assay And Multiple Regression Model For The Detection Of Rhodococcus Corprophilus, Stephen Clark

Environmental & Water Resources Engineering Masters Projects

Rhodococcus coprophilus is an emerging tool in the microbial source tracking "tool-box". The actinomycete is a source specific indicator for grazing animal fecal contamination. Once thought of as less harmful to human health, concern over animal fecal contamination has increased with the greater understanding of zoonoses. Zoonotic organisms that have the ability to cause disease in both humans and animals. Major outbreaks from these pathogens have increased their awareness and created a need for better source water protection. The presence of Rhodococcus coprophilus has been shown to have the ability to indicate grazing animal fecal contamination but it's current detection …

Quantum Dots Coordinated With Conjugated Organic Ligands: New Nanomaterials With Novel Photophysics, Nathan L. Hammer, Todd S. Emrick, Michael D. Barnes

Todd S. Emrick

CdSe quantum dots functionalized with oligo-(phenylene vinylene) (OPV) ligands (CdSe-OPV nanostructures) represent a new class of composite nanomaterials with significantly modified photophysics relative to bulk blends or isolated components. Singlemolecule spectroscopy on these species have revealed novel photophysics such as enhanced energy transfer, spectral stability, and strongly modified excited state lifetimes and blinking statistics. Here, we review the role of ligands in quantum dot applications and summarize some of our recent efforts probing energy and charge transfer in hybrid CdSe-OPV composite nanostructures

A Molecular Model For Intercellular Synchronization In The Mammalian Circadian Clock, Tsz-Leung To, Michael A. Henson, Erik D. Herzog, Francis J. Doyle Iii

Michael A Henson

The mechanisms and consequences of synchrony among heterogeneous oscillators are poorly understood in biological systems. We present a multicellular, molecular model of the mammalian circadian clock that incorporates recent data implicating the neurotransmitter vasoactive intestinal polypeptide (VIP) as the key synchronizing agent. The model postulates that synchrony arises amongcircadian neurons because they release VIP rhythmically on a daily basis and in response to ambient light. Two basic cell types, intrinsically rhythmic pacemakers and damped oscillators, are assumed to arise from a distribution of Period gene transcription rates. Postsynaptic neurons show time-of-day dependent responses to VIP binding through a signaling cascade …

Designing Model Systems For Enhanced Adhesion, Al Crosby

Alfred Crosby

Nature provides inspiration for enhanced control of adhesion through numerous examples ranging from geckos to jumping spiders. The primary strategy in these examples is the incorporation of patterns, specifically high-aspect-ratio topographic features, to ingeniously maximize adhesion forces while maintaining ease of release. Recently, considerable research efforts have been devoted toward the understanding, development, and optimization of synthetic analogues to these examples in nature. In this article, we provide insight into the mechanisms that lead to enhanced control of interfacial properties through patterning, the strategies that can be used for fabricating synthetic patterns, and an overview of experimental results that have …

Ethics Across The Curriculum Modules For Eac Toolkit Workshops, William J. Frey, Jose A. Cruz-Cruz

Ethics in Science and Engineering National Clearinghouse

This collection of modules has been designed to show how the Ethics Across the Curriculum Toolkit project provides for the preparation and pairing of student and instructor modules. These modules have been brought together and paired to aid in Toolkit demonstrations designed for faculty developement workshops in ethics across the curriculum.

Abstract by author.

Climate Teleconnections To Yangtze River Seasonal Streamflow At The Three Gorges Dam, China, Casey Brown, K. Xu, H.-H. Kwon, U. Lall, J. Zhang, S. Hayashi, Z. Chen

Casey Brown

In this study, we identify climatic influences on summer monsoon inflow to the Three Gorges Dam (TGD) in the Yangtze River Basin and use indices of these influences to predict streamflow one season ahead. Summer monsoon streamflow at Yichang hydrological station (YHS) was analyzed for the period 1882–2003. Statistical analysis was used to develop a predictive model for summer streamflow using preceding climate variables. Linear correlation maps were constructed using 3-month ahead climate fields to identify regions that exhibit teleconnections with streamflow at Yichang. The analysis revealed regions in the eastern Indian and western Pacific Oceans that influence YHS streamflow. …

Ethics Bowl Competition As Capstone Activity For Practical And Professional Ethics Classes, William J. Frey, Jose A. Cruz-Cruz

Ethics in Science and Engineering National Clearinghouse

In Connexions, a course is both a course (what is offered in a school curriculum) and a collection of modules. This course as a collection of modules has been designed to pull together the modules published in Connexions by this author for the purpose of showing different aspects of the Ethics Bowl competition and how it can be used in a university course on practical and professional ethics. The Ethics Bowl concept comes from Robert Ladenson of the Illinois Institute of Technology. Through the Association of Practical and Professional Ethics, the Ethics Bowl competition has been carried out nationally for …

Further Studies Of A Simple Atomistic Model Of Silica: Thermodynamic Stability Of Zeolite Frameworks As Silica Polymorphs, Peter A. Monson, S. M. Auerbach, M. H. Ford

Peter A. Monson

We have applied our previously reported model of silica based on low coordination and strong association [ J. Chem. Phys. 121, 8415 (2004) ], to the calculation of phase stability of zeolite frameworks SOD, LTA, MFI, and FAU as silica polymorphs. We applied the method of Frenkel and Ladd for calculating free energies of these solids. Our model predicts that the MFI framework structure has a regime of thermodynamic stability at low pressures and above ∼ 1400 K, relative to dense phases such as quartz. In contrast, our calculations predict that the less dense frameworks SOD, LTA, and FAU exhibit …

Using Case Studies In Teaching Research Ethics, Kenneth D. Pimple

Ethics in Science and Engineering National Clearinghouse

No abstract provided.

Humanitarian Engineering: Ethics, Theory, Practices, Juan C. Lucena, Jon Leydens, Carl Mitcham, Junko Munakata-Marr, Jay Straker

Ethics in Science and Engineering National Clearinghouse

This course is an introduction to humanitarian engineering from ethical, cultural, and practical perspectives. Through this course, faculty and students will collectively develop and refine a set of humanitarian engineering ethics criteria (constraints). Students will then critically apply these criteria to specific examples of humanitarian technologies, including one that they will research and develop into a case-study. Students will also research multiple career pathways in humanitarian-related organizations and practices and consider potential careers as humanitarian scientists and engineers.

Cavitation Rheology For Soft Materials, Jessica A. Zimberlin, Naomi Sanabria-Delong, Gregory N. Tew, Alfred Crosby

Alfred Crosby

To guide the development of tissue scaffolds and the characterization of naturally heterogeneous biological tissues, we have developed a method to determine the local modulus at an arbitrary point within a soft material. The method involves growing a cavity at the tip of a syringe needle and monitoring the pressure of the cavity at the onset of a mechanical instability. This critical pressure is directly related to the local modulus of the material. The results focus on the network development of poly(lactide)–poly(ethylene oxide)–poly(lactide) triblock copolymer and poly(vinyl alcohol) hydrogels. These materials serve as model materials for tissue scaffolds and soft …

Water Hammer Dissipation In Pneumatic Slug Tests, Don Degroot, David W. Ostendorf, Philip J. Dunaj

Don DeGroot

We model and measure the dissipation of water hammer induced by well casing and water elasticity with rapid valve opening at the start of a pneumatic slug test. The higher-frequency water hammer can obscure slower, aquifer-controlled, underdamped oscillations of the rigid water column, so a quantitative description of the elastic motion improves the ability of a slug test to calibrate the aquifer permeability k. Internal friction attenuates the water hammer, subject to a known headspace pressure at the air/water interface and equilibrium pressure at the top of the well screen. An analytical elastic solution is presented and matched to an …

Basin-Scale Methodology For Evaluating Relative Impacts Of Pollution Source Abatement, James T. Mangarillo

Environmental & Water Resources Engineering Masters Projects

The Blackstone River watershed covers an area of 475 me in central Massachusetts and northern Rhode Island. The Blackstone flows from its headwaters in the hills above Worcester, MA, through Woonsocket, RI and finally joins the Seekonk River in Pawtucket, RI. The Seekonk then flows into the Providence River on its way into Narragansett Bay. The historical significance of the Blackstone River has been recognized at the federal, state and local levels. Furthermore, the Blackstone is known to playa significant role on the hydrology and ecology of Narragansett Bay. This study is part of a larger study designed to evaluate …