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2014

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Articles 1591 - 1620 of 7238

Full-Text Articles in Engineering

Improved Microrobotic Control Through Image Processing And Automated Hardware Interfacing, Archit R. Aggarwal, Wuming Jing, David J. Cappelleri Aug 2014

Improved Microrobotic Control Through Image Processing And Automated Hardware Interfacing, Archit R. Aggarwal, Wuming Jing, David J. Cappelleri

The Summer Undergraduate Research Fellowship (SURF) Symposium

Untethered submilliliter-sized robots (microrobots) are showing potential use in different industrial, manufacturing and medical applications. A particular type of these microrobots, magnetic robots, have shown improved performance in power and control capabilities compared to the other thermal and electrostatic based robots. However, the magnetic robot designs have not been assessed in a robust manner to understand the degree of control in different environments and their application feasibility. This research project seeks to develop a custom control software interface to provide a holistic tool for researchers to evaluate the microrobotic performance through advance control features. The software deliverable involved two main …


Population Balance Modeling Of Conjugation In Enterococcus Faecalis, Jeremy Binagia, Vu Tran, Che-Chi Shu, Doraiswami Ramkrishna Aug 2014

Population Balance Modeling Of Conjugation In Enterococcus Faecalis, Jeremy Binagia, Vu Tran, Che-Chi Shu, Doraiswami Ramkrishna

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the bacteria species Enterococcus faecalis, transfer of plasmid pCF10 by conjugation between donor cells that possess sets of genes conferring drug resistance and recipient cells leads to the spread of this resistance in a population. A complex signaling molecule network is responsible for communication between recipient and donor cells. Up to this point, the nature of these signaling molecules has been modeled deterministically from the point of view of an “average” cell. While this view has been cured slightly by stochastic treatments, a model is needed that better accounts for the individual nature of each cell, each cell’s interactions …


Dynamic Response Of Textile Material Under Transverse Impact, Yuchen Zheng, Matthew C. Hudspeth, Weinong W. Chen Aug 2014

Dynamic Response Of Textile Material Under Transverse Impact, Yuchen Zheng, Matthew C. Hudspeth, Weinong W. Chen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Textile materials, such as Dyneema and Kevlar, are the major raw materials for state of the art military or personal security armor vests. However, in impact experiments, actual observed penetration speed is much lower than theoretically predicted penetration speed. Each armor vest is composed of high performance yarns which are woven together to form fabrics, which when stacked together form a vest. Understanding penetration behavior of yarns is essential to evaluate the performance of fabric, which will be useful for the design of better vests. The project is composed of three parts: static experiments, dynamic yarn experiments and dynamic fabric …


Thermo-Mechanical Modeling Of Carbon Nanotube Thermal Interfaces, Yide Wang, Sridhar Sadasivam, Timothy S. Fisher Aug 2014

Thermo-Mechanical Modeling Of Carbon Nanotube Thermal Interfaces, Yide Wang, Sridhar Sadasivam, Timothy S. Fisher

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the last decade, much research has attempted to develop a highly conducting and mechanically reliable thermal interface material. Vertically aligned carbon nanotube arrays (CNTs) is a promising thermal interface material due to the high thermal conductivity of each CNT and the mechanical compliance of CNT arrays [1].

The computational modeling of CNTs is usually at an atomistic scale; however, atomistic simulations are computationally expensive for modeling macroscopic CNT arrays used in experiments. Coarse grain simulation techniques [2] have been developed to reduce the number of degrees of freedom and hence making large scale simulations computationally tractable. The purpose of …


The Influence Of Lightweight Aggregate On Internal Curing And Its Impact On Autogenous Shrinkage Of High-Performance Concrete, Neil J. Hartman, Timothy J. Barrett, Jason Weiss Aug 2014

The Influence Of Lightweight Aggregate On Internal Curing And Its Impact On Autogenous Shrinkage Of High-Performance Concrete, Neil J. Hartman, Timothy J. Barrett, Jason Weiss

The Summer Undergraduate Research Fellowship (SURF) Symposium

In bridge deck construction high performance concrete is often desirable, however in practice it is generally susceptible to early-age shrinkage cracking resulting in an overall reduction in service life. This research seeks to assess the potential for reducing early-age shrinkage in new bridge deck construction through the use of internal curing, a process in which internal reservoirs supply water to the hydrating cement paste during the early stages of cement hydration. In North America, internal curing is typically achieved by replacing a portion of the normal fine aggregate with an expanded fine lightweight aggregate (LWA). For this study, the free …


Quantification Of Lps Eluate From Coated Microelectrode Devices, Jahrane A. Dale, Janak Gaire, Kevin J. Otto Aug 2014

Quantification Of Lps Eluate From Coated Microelectrode Devices, Jahrane A. Dale, Janak Gaire, Kevin J. Otto

The Summer Undergraduate Research Fellowship (SURF) Symposium

Penetrating microelectrode arrays have a great potential to be used as control and communication interfaces for neuroprosthetics. A persistent obstacle in the clinical implementation of microelectrode arrays is the chronic degradation of these devices, putatively due to the foreign body response. Though researchers have studied the progression of the foreign body response and the effect of anti-inflammatory drugs on the efficacy of the implant, the exact biological mechanisms of implant degradation are not fully understood. To more closely investigate the effect of the foreign body response on device degradation, neuroinflammation can be exacerbated by coating dummy electrodes implanted into mice …


Nonlinear Optical Microscopy Of Murine Abdominal Aortic Aneurysm, Katherine E. Wilson, Alexa A. Yrineo, Amelia J. Adelsperger, Hilary D. Schroeder, Delong Zhang, Jesse Zhang, Chien-Sheng Liao, Frederick W. Damen, Ji-Xin Cheng, Evan H. Phillips, Craig J. Goergen Aug 2014

Nonlinear Optical Microscopy Of Murine Abdominal Aortic Aneurysm, Katherine E. Wilson, Alexa A. Yrineo, Amelia J. Adelsperger, Hilary D. Schroeder, Delong Zhang, Jesse Zhang, Chien-Sheng Liao, Frederick W. Damen, Ji-Xin Cheng, Evan H. Phillips, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysm (AAA) is a cardiovascular disease characterized by dilation and weakening of the vessel wall. AAA rupture is responsible for approximately 14,000 deaths annually in the United States [1]. Nonlinear optical (NLO) microscopy presents new possibilities for analyzing AAA tissue samples from murine models. Common NLO techniques are two-photon excitation fluorescence (TPEF), which detects the intrinsic autofluorescent properties of elastin, and second-harmonic generation (SHG), which is specific for collagen fibrils. Elastin and collagen, two major extracellular matrix components, help the aortic wall withstand internal pressure. Murine AAAs were created through 1) subcutaneous continuous systemic infusion of angiotensin II …


Designing Constructed Wetlands For Water Purification In Tanzania, Danielle Mcneely, Michael Sheehan, John Lumkes Aug 2014

Designing Constructed Wetlands For Water Purification In Tanzania, Danielle Mcneely, Michael Sheehan, John Lumkes

The Summer Undergraduate Research Fellowship (SURF) Symposium

In Tanzania half of households have unsafe drinking water (Nkonya, 2010) and many diseases arise from poor water quality, including meningitis, hepatitis A and E, and salmonella (Kusiluka et al., 2004). One cost-effective way of cleaning water is by passing it through a wetland. This research is focused on simplifying the process of horizontal subsurface flow wetland construction for the villagers of Endallah. The outcome is an Excel tool that standardizes methodology for building wetlands that can then be applied to Endallah. Rainfall data from the Arusha region of Tanzania was used to make a rainfall estimation grid. From this …


Chronic Brain Stimulation Using Micro-Ecog Devices, Hayden C. Carney, Roy Lycke, Kevin J. Otto, Amelia A. Schendel, Justin Williams Aug 2014

Chronic Brain Stimulation Using Micro-Ecog Devices, Hayden C. Carney, Roy Lycke, Kevin J. Otto, Amelia A. Schendel, Justin Williams

The Summer Undergraduate Research Fellowship (SURF) Symposium

Recording and stimulating brain activity has had great success both as a research tool and as a clinical technique. Neural prosthetics can replace limbs, restore hearing, and treat disorders like Parkinson’s and epilepsy, but are relatively crude. Current neural prosthetic systems use penetrating electrodes to achieve high precision, but the invasive nature of these devices provoke a strong immune response that limits chronic use. (Polikov et al) In our study we evaluate micro-electrocortiographic (micro-ECoG) devices which sit under the skull and on the surface of the brain for stimulation over chronic timescales. We anticipate these devices with their less invasive …


Modeling Of Mixed Friction Interactions Occurring In Axial Piston Pumps, Andrew C. Adelsperger, Lizhi Shang, Dan Mizell, Monika Ivantysynova Aug 2014

Modeling Of Mixed Friction Interactions Occurring In Axial Piston Pumps, Andrew C. Adelsperger, Lizhi Shang, Dan Mizell, Monika Ivantysynova

The Summer Undergraduate Research Fellowship (SURF) Symposium

Axial piston pumps are integral to a variety of hydraulic systems due to their versatility and reliability, but most attempts to model them for design purposes have failed. However, software which fully models the fluid structures within these pumps, such as the FSTI gap design program, has improved significantly. Unfortunately, current discrepancies between simulated and measured friction forces on the cylinder due to the fluid drag and piston movement need to be eliminated so that more accurate simulation of these pumps in operation is possible. Friction measurements and FSTI simulation outputs were analyzed with MATLAB filters and graphs, resulting in …


Effect Of Twin Screw Granulator Process Parameters On Granule Attributes, Haosheng Xu, Ridade Sayin, James Litster Aug 2014

Effect Of Twin Screw Granulator Process Parameters On Granule Attributes, Haosheng Xu, Ridade Sayin, James Litster

The Summer Undergraduate Research Fellowship (SURF) Symposium

Twin screw wet granulation has been considered as an efficient and effective technique of manufacturing granules (agglomerates made up of small particles) and has been widely applied in pharmaceutical industry. However, narrow granule size distributions are difficult to achieve. This study aims to elucidate the effect of process parameters such as liquid feed rate and screw configuration on the granule attributes through granule characterization. The methods used are sieve analysis (for size distribution), liquid distribution (determining the dye concentration in the granules) and density and porosity (percentage gas volume in the granule) analyses. A sieve shaker is used to divide …


Characterization Of Swelling Ratio And Water Content Of Hydrogels For Cartilage Engineering Applications, Emily E. Gill, Renay S.-C. Su, Julie C. Liu Aug 2014

Characterization Of Swelling Ratio And Water Content Of Hydrogels For Cartilage Engineering Applications, Emily E. Gill, Renay S.-C. Su, Julie C. Liu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Due to the high prevalence of arthritis and cartilage-related injuries, tissue engineers are studying ways to grow cartilage tissue replacements. Resilin, an elastomeric protein found in insect cuticles, is known for its extraordinary resilience and elasticity. In previous studies, recombinant resilin-based hydrogels, or cross-linked protein networks, exhibited potential for use in cartilage tissue scaffolds. Our lab successfully developed resilin-based proteins with a sequence based on the mosquito gene and showed that resilin-based hydrogels possess mechanical properties of the same order of magnitude as native articular cartilage. In addition, these mechanical properties can be controlled by changing the protein concentration. To …


Thermal Properties Of Soft Nanomaterials: Materials Synthesis And Fabrication, Meng Pan, Collier Miers, Amy Marconnet, Yu Han Aug 2014

Thermal Properties Of Soft Nanomaterials: Materials Synthesis And Fabrication, Meng Pan, Collier Miers, Amy Marconnet, Yu Han

The Summer Undergraduate Research Fellowship (SURF) Symposium

The properties of soft nanomaterials are hard to measure exactly due to their mechanical properties and unstable shape. In particular, hydrogels are a class of cross-linked polymers that can absorb large quantities of water changing their shape under the influence of various conditions such as humidity, temperature, and pH. This research addresses the fabrication of a material that has a significant contrast in properties under different conditions (e.g. temperature, wetting, and pH) and determine the physical mechanisms of heat transfer in this nanomaterial. The hydrogels are made using a several cycles of a freeze-thaw method. The method requires soluble material. …


Solar-Combined Thermoelectric Power Generation Simulator, Hemanth Mullangi Chenchu, Kazuaki Yazawa, Je-Hyeong Bahk Aug 2014

Solar-Combined Thermoelectric Power Generation Simulator, Hemanth Mullangi Chenchu, Kazuaki Yazawa, Je-Hyeong Bahk

The Summer Undergraduate Research Fellowship (SURF) Symposium

Photovoltaic (PV) devices are gaining popularity in harnessing solar energy as a form of sustainable energy source to generate electricity. However, these devices including tandem PV cells are limited to utilizing only high energy photons from the solar spectrum. This curtails their efficiency restricting them from being employed in mega Watts scale power generation. This study develops a software tool that allows engineers to tap into the wasted wavelengths of the spectrum by adding a thermoelectric (TE) module and a bottoming steam turbine cycle thus spreading the use of the spectrum. The tool allows investigating how power output and thus …


Simulation Of Bio-Inspired Porous Battery Separators, Yumeng Xie, Edwin Garcia, Aniruddha Jana Aug 2014

Simulation Of Bio-Inspired Porous Battery Separators, Yumeng Xie, Edwin Garcia, Aniruddha Jana

The Summer Undergraduate Research Fellowship (SURF) Symposium

Li-Ion rechargeable battery is one of the most-used rechargeable batteries around the industry of the world. The battery is most used in most electronic devices, electrical cars. But the battery separator is one of the mainly problem that limits the service life. If we can find the way to improve the performance of the battery separator, we can highly increase the service life of the Li-Ion battery. The goal of the project 'Simulation of Bio-Inspired Porous Battery Separators' is to generate a tool for users in order to create computer models of bio-inspired porous structures that resemble porous separators layer …


Double-Pulse Nd:Yag-Co2 Libs Excitation For Bulk And Trace Analytes, Jason R. Becker, Patrick Skrodzki, Prasoon Diwakar, Sivanandan Harilal, Ahmed Hassanein Aug 2014

Double-Pulse Nd:Yag-Co2 Libs Excitation For Bulk And Trace Analytes, Jason R. Becker, Patrick Skrodzki, Prasoon Diwakar, Sivanandan Harilal, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Laser-induced breakdown spectroscopy [LIBS] is a commonly used technique for multi-element analyses for various applications such as space exploration, nuclear forensics, environmental analysis, process monitoring. The advantages of the LIBS technique include robustness, ease of use, field portability, and real-time, non-invasive multi-element analyses. However, in comparison to other lab based analytical techniques, it suffers from low precision and low sensitivity. In order to overcome these drawbacks, various approaches have been used, including double-pulse LIBS [DPLIBS]. Typically, various wavelength combinations of two Nd: yttrium aluminum garnet [YAG] lasers have been used for DPLIBS. However, the use of long wavelength (CO2 …


Monitoring Hydroxyurea Treatment Of Sickle Cell Anemia, Adhit Ramamurthi, Jayachandran Devaraj, Doraiswami Ramkrishna Aug 2014

Monitoring Hydroxyurea Treatment Of Sickle Cell Anemia, Adhit Ramamurthi, Jayachandran Devaraj, Doraiswami Ramkrishna

The Summer Undergraduate Research Fellowship (SURF) Symposium

Sickle cell is a hereditary disease affecting more than 100,000 people in the United States alone that causes hemoglobin in red blood cells to polymerize and turn the cell into a sickle shape, resulting in severe vaso-occlusive crises and ischemic attacks. Sickle cell patients often suffer from pain crises, with the number of pain crises linked to their prognosis, especially at a younger age. Currently, the drug hydroxyurea (HU) is used to treat the disease, with a measure of red blood cell volume (RBC MCV) as monitor for treatment progression. However, physicians have to wait atleast 120 days to identify …


Roundabout Maintenance Manual, Emily A. Bonini, Pat Conner P.E., John Haddock Phd, P.E., Yu Tian Aug 2014

Roundabout Maintenance Manual, Emily A. Bonini, Pat Conner P.E., John Haddock Phd, P.E., Yu Tian

The Summer Undergraduate Research Fellowship (SURF) Symposium

In recent years, roundabouts have been rapidly growing in popularity. As a result, many communities are installing them in their roadways; however, they are encountering difficulties in maintaining them. Uneducated workers can cause damage to roundabouts and to themselves, costing cities time and money. This project aims to create a guide for communities new to roundabouts in order to reduce damages and unnecessary maintenance costs. Data was gathered by determining the most common maintenance questions and problems along with what information was already available on roundabout maintenance. Next, agencies most experienced with roundabouts were surveyed on the best maintenance practices. …


Modeling Thermophotovoltaic Rare Earth Based Selective Emitters, Anubha Mathur, Enas Said Sakr, Peter Bermel Aug 2014

Modeling Thermophotovoltaic Rare Earth Based Selective Emitters, Anubha Mathur, Enas Said Sakr, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermophotovoltaic (TPV) devices convert heat to electricity using thermal radiation to illuminate a photovoltaic (PV) diode. Typically, this radiation is generated by a blackbody-like emitter. Such an emission spectrum includes a broad range of wavelengths, but only higher energy photons can be converted by the PV diode, which severely limits efficiencies. Thus, introducing a selective emitter and filter to recycle unwanted photons could potentially greatly enhance performance. In this work, we consider a rare earth-doped selective emitter structure to increase the number of photons emitted above the bandgap of the photovoltaic (PV) cell, while minimizing the total power emitted below …


Design And Fabrication Of A Novel Electrospinning System For Musculoskeletal Tissue Regeneration, Carter L. Chain, Maggie R. Del Ponte, Meng Deng, Feng Yue, Shihuan Kuang Aug 2014

Design And Fabrication Of A Novel Electrospinning System For Musculoskeletal Tissue Regeneration, Carter L. Chain, Maggie R. Del Ponte, Meng Deng, Feng Yue, Shihuan Kuang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Disease and injury to human tissue, especially musculoskeletal tissue, is a prevalent concern to the public, affecting millions of people each year. Current treatment options involving autografts and allografts are hindered by limited availability and risk of immunogenicity, respectively. In order to overcome these limitations, a transdisiplinary regenerative engineering strategy has emerged with a focus on the development of biomimetic scaffolds that closely mimic the properties of the native tissues. For example, the structure of muscle tissue is characterized by oriented muscle fibers. However, fabrication of aligned nanofiber structures that mimic the anisotropic organization of muscle presents significant engineering challenges. …


Understanding And Assessing Engineering Practices In Indian Context, Rudie Desravines, Brent Jesiek, Kavitha Ramane, Qin Zhu Aug 2014

Understanding And Assessing Engineering Practices In Indian Context, Rudie Desravines, Brent Jesiek, Kavitha Ramane, Qin Zhu

The Summer Undergraduate Research Fellowship (SURF) Symposium

For engineers and other technical professionals, working with individuals in a global context is often challenging and requires understanding and openness to other cultures. However, the core of engineering education has historically been focused on mathematical and technical foundations, with a lack of emphasis on broader capabilities such as global competency. Further research is needed to better understand differences in engineering education and practice across national and cultural boundaries, as well as to develop new instructional content and assessment techniques to improve and evaluate the global competency of engineering students and other technical professionals. This project addressed these needs through …


Portable Pneumatic Demonstrator For Stem Education, Joe Chege, Tyler Helmus, John Lumkes Aug 2014

Portable Pneumatic Demonstrator For Stem Education, Joe Chege, Tyler Helmus, John Lumkes

The Summer Undergraduate Research Fellowship (SURF) Symposium

This project involves the development of a compact and portable pneumatic demonstrator. Using two pneumatic actuators and four solenoid valves, we are able to move an arm on both the X and Y-axes; one actuator for each range of motion. The setup also employs an air pump and a tank to maintain pressure for the actuators. On the actuators there is an arm that holds a camera, a stepper motor and an electromagnet. The stepper motor raises and lowers the electromagnet which is used to pick up objects. The camera is used to automatically identify objects for when the demonstrator …


Radical Polymers As Anodic Charge Extraction Layers In Small Molecule Organic Photovoltaic Devices, Krystopher S. Jochem, Aditya G. Baradwaj, Bryan W. Boudouris Aug 2014

Radical Polymers As Anodic Charge Extraction Layers In Small Molecule Organic Photovoltaic Devices, Krystopher S. Jochem, Aditya G. Baradwaj, Bryan W. Boudouris

The Summer Undergraduate Research Fellowship (SURF) Symposium

Organic photovoltaic (OPV) devices based on the copper (II) phthalocyanine(CuPc)/ fullerene(C60) system are an innovative photovoltaic technology optimal for situations requiring low-cost, transparent, and flexible devices. Furthermore, the high degree of reproducibility of this system allows for the ready study of new OPV technologies. Here, we have used this system to elucidate systematic structure-property-performance relationships for a new OPV anode modifier. The addition of interfacial modifier materials between the organic CuPc/C60 layers and the metallic anode drastically can improve efficiency. Radical polymers are a class of polymers with aliphatic backbones and pendent stabilized radical groups. Here, we …


Wirelessly Powered And Transmitting Current Sensing Device, Christopher Quinkert, Steven Lee, Pedro Irazoqui Aug 2014

Wirelessly Powered And Transmitting Current Sensing Device, Christopher Quinkert, Steven Lee, Pedro Irazoqui

The Summer Undergraduate Research Fellowship (SURF) Symposium

As the rate of incidence of diabetes increases in the modern world, more accurate and reliable methods of glucose detection must be developed for patients with diabetes. Currently, 25.8 million people have diabetes in the United States alone and account for $174 billion in healthcare costs annually [1]. Devices that can be used without the need for as much patient interaction, regular replacement, or great patient expenses would be a large step forward in the ability of doctors and patients to effectively manage diabetes. To measure glucose concentrations in vivo, a biosensor is used to transduce glucose to an electrical …


Visual Feedback On The Effects Of Temperature, Moisture, Relative Humidity, Solar Radiation, Wind And Precipitation On Growth And Production Of Grapes., Justus Karenzi, Calvin Yau, Sunghan Ko, David Ebert Aug 2014

Visual Feedback On The Effects Of Temperature, Moisture, Relative Humidity, Solar Radiation, Wind And Precipitation On Growth And Production Of Grapes., Justus Karenzi, Calvin Yau, Sunghan Ko, David Ebert

The Summer Undergraduate Research Fellowship (SURF) Symposium

Weather conditions such as Temperature, Relative Humidity, Solar Radiation, and wind have reportedly been the primary cause to the significant difference in the growth of grape vines across the world. Past research findings have clearly studied the underlying effects of these weather parameters on the growth of grapes, but minimum work has been done on how to accurately turn this data into useful information. This paper aims at providing an overview on how to manage, analyze, and finally visualize the weather data in a way that is convenient to the farmers and can therefore help in the growth of grapes. …


Bayesian Calibration Tool, Sveinn Palsson, Martin Hunt, Alejandro Strachan Aug 2014

Bayesian Calibration Tool, Sveinn Palsson, Martin Hunt, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Fitting a model to data is common practice in many fields of science. The models may contain unknown parameters and often, the goal is to obtain good estimates of them. A variety of methods have been developed for this purpose. They often differ in complexity, efficiency and accuracy and some may have very limited applications. Bayesian inference methods have recently become popular for the purpose of calibrating model's parameters. The way they treat unknown quantities is completely different from any classical methods. Even though the unknown quantity is a constant, it is treated as a random variable and the desired …


The Simulation Of Resonant Tunneling Diodes, Woodrow A. Gilbertson, Pengyu Long, Jim Fonseca, Gerhard Klimeck Aug 2014

The Simulation Of Resonant Tunneling Diodes, Woodrow A. Gilbertson, Pengyu Long, Jim Fonseca, Gerhard Klimeck

The Summer Undergraduate Research Fellowship (SURF) Symposium

The goal of this project is to improve the simulation of an electrical device known as a Resonant Tunneling Diode (RTD). Diodes are in most electronic devices today, but RTDs have 10 times greater switching speeds than regular diodes. This increase in efficiency would have impacts from supercomputers to the next big cell phone. The increased functionality of the simulation tool will come from implementing more recent mathematical solvers and modeling techniques. The simulation tool makes use of a variant of Non-Equilibrium Green Functions (NEGF) with an effective mass approximation. The two contacts are treated as equilibrium regions and the …


Rheo-Piv Investigation Of Fracture And Self-Healing In A Triblock Copolymer Gel, Benjamin A. Helfrecht, Travis L. Thornell, Kendra A. Erk Aug 2014

Rheo-Piv Investigation Of Fracture And Self-Healing In A Triblock Copolymer Gel, Benjamin A. Helfrecht, Travis L. Thornell, Kendra A. Erk

The Summer Undergraduate Research Fellowship (SURF) Symposium

Physically associating polymer gels have shown the ability to heal after failure, making them promising candidates for various medical applications or consumer products. However, the processes by which these materials self-heal is not well-understood. This study seeks to explain the self-healing behavior of the triblock copolymer poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate), or PMMA-PnBA-PMMA, by probing the material’s post-fracture behavior with rheometry and particle image velocimetry (PIV). The self-healing behavior was studied by deforming each gel in shear until failure multiple times with “recovery” periods in-between. PIV was used to verify the occurrence of each fracture in both time and space. Stress …


Effect Of Sodium Dodecyl Sulfate And Sodium Chloride On The Stability Of Aqueous Dispersions Of Tio2 Particles Against Aggregation And Sedimentation, Xilan Zhu, Guanrong Bai, Elias I. Franses, David S. Corti, Yung-Jih Yang Aug 2014

Effect Of Sodium Dodecyl Sulfate And Sodium Chloride On The Stability Of Aqueous Dispersions Of Tio2 Particles Against Aggregation And Sedimentation, Xilan Zhu, Guanrong Bai, Elias I. Franses, David S. Corti, Yung-Jih Yang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Dispersions of TiO2 particles are widely used as the main pigment in white inks for inkjet printers due to its brightness and high opacity. The TiO2 particles, however, have a high density, and so the possible fast settling of these particles can cause maintenance problems for the printers and lower the printing quality. We studied the effect of sodium dodecyl sulfate (SDS), a commonly used dispersant, on the stability of 1 wt% TiO2 aqueous dispersions, both with and without NaCl, against aggregation and sedimentation. The sedimentation half time (t50), defined as the time need for the particles to …


Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells, Abhirit Kanti, Raghu Vamsi Krishna Chavali, Mark S. Lundstrom Phd, Muhammad A. Alam Phd Aug 2014

Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells, Abhirit Kanti, Raghu Vamsi Krishna Chavali, Mark S. Lundstrom Phd, Muhammad A. Alam Phd

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thin film solar cells have higher absorption coefficients than traditional Silicon solar cells. This means that lesser material is required to produce the same power output for a given intensity of solar illumination. As a result, they are less expensive, easier to install and have a wider range of applications. Analyzing the performance of cells requires separating the current into the photocurrent and the injection current based on the ‘Superposition Principle’. For thin film solar cells, this cannot be done using the conventional method. This is because these components are interdependent, and so modeling one’s behavior requires understanding the other. …