Engineering Commons^™

Informativeness And The Computational Metrology Of Collaborative Adaptive Sensor Systems, Anthony P. Hopf

Open Access Dissertations

Complex engineered systems evolve, with a tendency toward self-organization, which can, paradoxically, frustrate the aims of those seeking to develop them. The systems engineer, seeking to promote the development in the context of changing and uncertain requirements, is challenged by conceptual gaps that emerge within engineering projects, particularly as they scale up, that inhibit communication among the various stakeholders. Overall optimization, involving multiple criterion, is often expressed in the language of the individual parties, increasing the complexity of the overall situation, subsuming the participants within the evolution of the complex engineered system, containing the objective and subjective in counterproductive or …

Computational Analysis Of Structural Transformations In Carbon Nanostructures Induced By Hydrogenation, Andre R. Muniz

Open Access Dissertations

Carbon nanomaterials, such as carbon nanotubes and graphene, have attracted significant interest over the past several years due to their outstanding and unusual combination of physical properties. These properties can be modified in a controllable way by chemical functionalization in order to enable specific technological applications. One example is hydrogenation, achieved by the exposure of these materials to a source of atomic hydrogen. This process has been considered for hydrogen storage purposes and for the control of the band gap of these materials for applications in carbon-based electronics. Hydrogen atoms are chemisorbed onto the surface of these materials, introducing sp3-hybridized …

The Parameter Signature Isolation Method And Applications, James Richard Mccusker

Open Access Dissertations

The aim of this research was to develop a method of system identification that would draw inspiration from the approach taken by human experts for simulation model tuning and validation. Human experts are able to utilize their natural pattern recognition ability to identify the various shape attributes, or signatures, of a time series from simulation model outputs. They can also intelligently and effectively perform tasks ranging from system identification to model validation. However, the feature extraction approach employed by them cannot be readily automated due to the difficulty in measuring shape attributes. In order to bridge the gap between the …

News Media Environment, Selective Perception, And The Survival Of Preference Diversity Within Communication Networks, Frank C.S. Liu, Paul E. Johnson

JITP 2011: The Future of Computational Social Science

There is a natural tension between the effects on public opinion of social networks and the news media. It is widely believed that social networks tend to harmonize opinions within them, but the presence of media may accentuate diversity by inserting discordant messages. On the other hand, in a totalitarian state where the government controls the media, social networks may mitigate the homogenizing pressure of a regime’s propaganda. The tendency of opinion to follow the “official line” may be mitigated because opponents of the government interact on a personal level and bolster one another’s views. This paper employs agent-based modeling—an …

Biodegradation Of Ethylene Dibromide (Edb) Under In Situ And Biostimulated Conditions At Mmr, Robert Mckeever

Environmental & Water Resources Engineering Masters Projects

An extensive microcosm study was conducted to investigate the biodegradation of 1,2-dibromoethane (EDB) under in situ and biostimulated conditions within a plume at the Massachusetts Military Reservation in Cape Cod, MA. This particular EDB plume is unique because it has persisted for over 38 years, is more than 61 m below the ground surface, and has both aerobic and anaerobic zones with EDB levels above the maximum contaminant level (MCL) of 0.05 μg/L (ppb). Microcosms were constructed with in situ materials and conducted under environmentally relevant conditions (field EDB concentrations; incubated at 12°C). The results showed that natural attenuation occurred …

2-D Spill Modeling In The Wachusett Reservoir With Cequal-W2 For Years 2003-2006, Bryan R. Sojkowski

Environmental & Water Resources Engineering Masters Projects

This study examines the effects of various environmental conditions on the behavior of a contaminant spill as it travels across the Wachusett Reservoir. The reservoir, located in central Massachusetts, is a 65 billion gallon water body that supplies drinking water to the Boston Metropolitan area and consists of numerous inflows and outflows. The Quabbin Reservoir, a 412 billion gallon system, accounts for close to half of the inflow. The Wachusett Reservoir receives Quabbin water through the Quabbin aqueduct located on its eastern side. CEQUAL W2, a two-dimensional, laterally averaged, hydrodynamic and water quality model was utilized to perform numerous simulations. …

Utilizing A Decision Support System To Optimize Reservoir Operations To Restore The Natural Flow Distribution In The Connecticut River Watershed, Brian Pitta

Environmental & Water Resources Engineering Masters Projects

Reservoir development on the Connecticut River Basin has altered the natural hydrograph and detrimentally affected the region's aquatic ecosystems that thrive on natural variability. This thesis examines ways in which flows in the river and its triburaries can be returned to a more natural regime withouy negatively impacting other users. The analysis offers alternative operations to meet the various objectives as well as evaluates the impacts of climate change on the basin. This paper focuses on the upper third of the basin as a proof of concept to demonstrate the decision support system and to generate initial results for the …

Conventional Water Treatment Processes For Removing Pharmaceutical And Endocrine Disrupting Compounds, Jing Lin

Environmental & Water Resources Engineering Masters Projects

Endocrine disrupting chemicals (EDCs) are natural or synthetic compounds that act like hormones in the endocrine system and disrupt the physiologic function of endogenous hormones. Although no standards concerning EDCs in drinking water have been established, there are rising concerns about the effects of EDCs in drinking water on human health.

The main objective of this study is to conduct bench scale experiments to investigate the effectiveness of conventional drinking water treatment processes at removing selected endocrine disrupting compounds (EDCs), pharmaceutical and personal care products (PPCPs) from municipal water supplies. It was also a goal of this work to provide …

Annual, Monthly, And Storm Scale Analysis Of Chloride Fluxes From Highway Deicing Agents To The Cambridge Reservoir, Marie Rivers

Environmental & Water Resources Engineering Masters Projects

This research project analyzed streamflow, specific conductivity, and precipitation data for two tributary locations of the Cambridge Reservoir. MassDOT deicing agent application data was also analyzed for state maintained roads in the drainage areas of the two tributaries. The purpose of this project was to determine the load of chloride to the reservoir from the state maintained roads. All data was considered on an annual, monthly, and individual storm scale. A hydraulic model for runoff was developed and the mass load of chloride was determined. The study area consisted of USGS gage 01104415 (Lincoln Street) which is a tributary to …

Steel Moment Frames Column Loss Analysis: The Influence Of Time Step Size, Simos Gerasimidis, C. Baniotopoulos

Civil and Environmental Engineering Faculty Publication Series

This paper applies two well-known structural dynamics computational algorithms to the problem ofdisproportionate collapse of steel moment frames applying the alternate load path method. Any problem of structural dynamics strongly depends on the accuracy and the reliability of the analysis method since the parameters involved in the selection of the appropriate algorithm are affected by the nature of the problem. Disproportionate collapse is herein simulated via a time history analysis used to ‘‘turn off’’ the effectiveness of an element to the structure. For this kind of problem the time step size of the computational algorithm is of major importance for …

Effect Of Stress State On Wrinkle Morphology, Derek Breid, Alfred Crosby

Alfred Crosby

Wrinkles in thin films on soft substrates have been shown to self-organize into topological patterns, providing a possible route towards inexpensive generation of surface microstructure. However, the effect of the magnitude of applied stress in relation to the critical buckling stress, or overstress, on the observed patterns has until this point been neglected experimentally. In this paper, we investigate the effect of overstress using poly(dimethylsiloxane) which has been surface-oxidized with a UV-ozone oxidation technique. Using a swelling-based stress application technique, where the applied swelling stress in the thin film is controlled by changing the concentration of vapor-phase swelling agent (ethanol) …

Disproportionate Collapse Analysis Of Cable-Stayed Steel Roofs For Cable Loss, Simos Gerasimidis, C. Baniotopoulos

Civil and Environmental Engineering Faculty Publication Series

Disproportionate collapse has been identified lately as a real cause of failure for structural engineering projects. Rare and unexpected, the phenomenon of disproportionate collapse usually results to many fatalities and thus, its analysis and mitigation is deemed necessary. This work describes the analysis of a cable-stayed steel roof under the scenario of a cable loss. The eventof a cable loss is assumed to be brittle, while relevant recent recommendations suggest the application of a scaled equivalent static force at the points of the anchorage of the cable but in the opposite direction of the original cable force. In this paper, …

Advanced Oxidation Of Drinking Water Using Ultraviolet Light And Alternative Solid Forms Of Hydrogen Peroxide, Zachary F. Monge

Environmental & Water Resources Engineering Masters Projects

With the increasing focus on removing emerging, unregulated drinking water contaminants, the use of advanced oxidation processes (AOPs) has become more prevalent. A commonly used AOP is the ultraviolet light/hydrogen peroxide (UV/H2O2) AOP. This process utilizes the formation of hydroxyl radicals to oxidize contaminants to less harmful forms. In this analysis, two alternative solid forms of H2O2, sodium perborate (SPB) and sodium percarbonate (SPC) were used as sources of H2O2 in the UV/H2O2 AOP. The potential advantage of SPB and SPC is that they are solids in nature, and as a result, the shipping costs and shipping energy requirements can …

Atomic-Scale Modeling Of Transition-Metal Doping Of Semiconductor Nanocrystals, Tejinder Singh

Open Access Dissertations

Doping in bulk semiconductors (e.g., n- or p- type doping in silicon) allows for precise control of their properties and forms the basis for the development of electronic and photovoltaic devices. Recently, there have been reports on the successful synthesis of doped semiconductor nanocrystals (or quantum dots) for potential applications in solar cells and spintronics. For example, nanocrystals of ZnSe (with zinc-blende lattice structure) and CdSe and ZnO (with wurtzite lattice structure) have been doped successfully with transition-metal (TM) elements (Mn, Co, or Ni). Despite the recent progress, however, the underlying mechanisms of doping in colloidal nanocrystals are not well …

Band Structure Calculations Of Strained Semiconductors Using Empirical Pseudopotential Theory, Jiseok Kim

Open Access Dissertations

Electronic band structure of various crystal orientations of relaxed and strained bulk, 1D and 2D confined semiconductors are investigated using nonlocal empirical pseudopotential method with spin-orbit interaction. For the bulk semiconductors, local and nonlocal pseudopotential parameters are obtained by fitting transport-relevant quantities, such as band gap, effective masses and deformation potentials, to available experimental data. A cubic-spline interpolation is used to extend local form factors to arbitrary q and the resulting transferable local pseudopotential V(q) with correct work function is used to investigate the 1D and 2D confined systems with supercell method. Quantum confinement, uniaxial and biaxial strain and crystal …

Modeling Of Flash Boiling Flows In Injectors With Gasoline-Ethanol Fuel Blends, Kshitij Deepak Neroorkar

Open Access Dissertations

Flash boiling may be defined as the finite-rate mechanism that governs phase change in a high temperature liquid that is depressurized below its vapor pressure. This is a transient and complicated phenomenon which has applications in many industries. The main focus of the current work is on modeling flash boiling in injectors used in engines operating on the principle of gasoline direct injection (GDI). These engines are prone to flash boiling due to the transfer of thermal energy to the fuel, combined with the sub-atmospheric pressures present in the cylinder during injection. Unlike cavitation, there is little tendency for the …

Low Cost Electronically Steered Phase Arrays For Weather Applications, Mauricio Sanchez-Barbetty

Open Access Dissertations

The Electronically Steered Phased Array is one of the most versatile antennas used in radars applications. Some of the advantages of electronic steering are faster scan, no moving parts and higher reliability. However, the cost of phased arrays has always been prohibitive - in the order of $1M per square meter. The cost of a phased array is largely impacted by the cost of the high frequency electronics at each element and the cost of packaging. Advances in IC integration will allow incorporating multiple elements such as low noise amplifier, power amplifier, phase shifters and up/down-conversion into one or two …

Pyrolysis Oils: Characterization, Stability Analysis, And Catalytic Upgrading To Fuels And Chemicals, Tushar Vispute

Open Access Dissertations

There is a growing need to develop the processes to produce renewable fuels and chemicals due to the economical, political, and environmental concerns associated with the fossil fuels. One of the most promising methods for a small scale conversion of biomass into liquid fuels is fast pyrolysis. The liquid product obtained from the fast pyrolysis of biomass is called pyrolysis oil or bio-oil. It is a complex mixture of more than 300 compounds resulting from the depolymerization of biomass building blocks, cellulose; hemi-cellulose; and lignin. Bio-oils have low heating value, high moisture content, are acidic, contain solid char particles, are …

Mechanical Evaluation Methods For Polymer And Composite Systems, Donna Theresa Wrublewski

Open Access Dissertations

This dissertation describes the development and application of various mechanical characterization techniques to four types of polymer composite materials. The composite nature of these materials ranges from molecular to macro-scale, as do the size scales probed by the techniques chosen. The two main goals of this work are to evaluate the suitability of existing characterization methods to new composite materials (and augment the methods as needed), and to use these methods to determine optimal composite system parameters to maximize the desired mechanical response. Chapter 2 employs nondestructive ultrasonic spectroscopy for characterizing the stiffness response of both micron-scale woven composites and …

Fiber Formation From The Melting Of Free-Standing Polystyrene, Ultra-Thin Films: A Technique For The Investication Of Thin Film Dynamics, Confinement Effects And Fiber-Based Sensing, Jeremy M. Rathfon

Open Access Dissertations

Free-standing ultra-thin films and micro to nanoscale fibers offer a unique geometry in which to study the dynamics of thin film stability and polymer chain dynamics. By melting these films and investigating the subsequent processes of hole formation and growth, and fiber thinning and breakup, many interesting phenomena can be explored, including the nucleation of holes, shear-thinning during hole formation, finite-extensibility of capillary thinning viscoelastic fibers, and confinement effects on entanglement of polymer chains. Free-standing films in the melt are unstable and rupture due to instabilities. The mechanism of membrane failure and hole nucleation is modeled using an energy barrier …

Managing Lithographic Variations In Design, Reliability, And Test Using Statistical Techniques, Aswin Sreedhar

Open Access Dissertations

Much of today's high performance computing engines and hand-held mobile devices are products of aggressive CMOS scaling. Technology scaling in semiconductor industry is mainly driven by corresponding improvements in optical lithography technology. Photolithography, the art used to create patterns on the wafer is at the heart of the semiconductor manufacturing process. Lately, improvements in optical technology have been difficult and slow. The transition to deep ultra-violet (DUV) light source (193nm) required changes in lens materials, mask blanks, light source and photoresist. It took more than ten years to develop a stable chemically amplified resist (CAR) for DUV. Consequently, as the …

Blowing Bubbles To Study Living Material, Alfred Crosby, Jennifer J. Mcmanus

Alfred Crosby

Living materials respond to stresses, or deformation forces, in profound and surprising ways. Bones become weak if they don’t carry weight. Muscles and soft tissues atrophy, or shrink, if exercise is limited. Whether stem cells differentiate into hard or soft tissue can strongly depend on the stresses they experience during growth. Therefore, to promote or direct the growth of healthy tissue—the challenge of tissue engineering—or to limit the growth of unwanted tissue such as cancerous tumors, scientists must understand the stresses that biological materials experience as they grow and live.

Multicompartment And Multigeometry Nanoparticle Assembly, Darrin J. Pochan, Jiahua Zhu, Ke Zhang, Karen L. Wooley, Caroline Miesch, Todd S. Emrick

Todd S. Emrick

The directed or dynamic assembly of molecular components in solution is a simple and effective strategy to confine materials in desired geometries and length scales. We use a kinetic control strategy with block copolymer blending to construct complex nanoparticles through the demixing of unlike block copolymers within the same nanoscale particle. Successful nanoparticle construction relies on kinetic trapping of unlike block copolymers into the same nanoparticle with solution processing. Not only can we make nanoparticles with multiple internal compartments of a desired size, but we can also make nanoparticles of hybrid geometries (e.g. a blend of cylindrical and spherical geometries). …

Pegylated Polymers For Medicine: From Conjugation To Self-Assembled Systems, Maisie J. Joralemon, Samantha Mcrae, Todd S. Emrick

Todd S. Emrick

Synthetic polymers have transformed society in many areas of science and technology, including recent breakthroughs in medicine. Synthetic polymers now offer unique and versatile platforms for drug delivery, as they can be “bio-tailored” for applications as implants, medical devices, and injectable polymer-drug conjugates. However, while several currently used therapeutic proteins and small molecule drugs have benefited from synthetic polymers, the full potential of polymer-based drug delivery platforms has not yet been realized. This review examines both general advantages and specific cases of synthetic polymers in drug delivery, focusing on PEGylation in the context of polymer architecture, self-assembly, and conjugation techniques …

Institute Overview, Morton Sternheim

STEM Digital

Digital cameras and computers are widely available for students and teachers. However, they are mainly used for documentation: creating PPT presentations, handouts, posters, etc. STEM DIGITAL shows how digital image analysis can be applied to environmental (and other) research in STEM courses. Application to studies of air quality, water quality, arsenic contamination, climate change, diffusion, etc.

Digital Camera Basics, Stephen Schneider

STEM Digital

No abstract provided.

Measuring Lengths And Areas With Adi. Student Guide, Morton Sternheim

STEM Digital

No abstract provided.

Measuring G With Movie Tracker, Stephen Schneider

STEM Digital

No abstract provided.

Detecting And Mixing Colors, Rob Snyder

STEM Digital

How can Analyzing Digital Images software reveal the differences between primary colors of light and primary colors of paints or pigments?

Measuring The Acceleration Of Falling Objects, John Pickle

STEM Digital

Earth's gravity pulls all objects toward its center, and near the Earth's surface. Objects in free fall accelerate at 9.8 m/s² vertically downward, provided air resistance is negligible. This value of acceleration is often referred to as "g". There are many ways to measure this rate of acceleration, and most require a timing device. Typically, stopwatches are the least expensive technology, so these are commonly available in high school science classrooms. With the recent addition of movie cameras on cell phones and digital cameras, another timing tool is available at moderate cost (free if the school policy …