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Friday, May 13, 2022
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3:00 PM
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4:00 PM
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Summer Financial Aid FAFSA Help Labs
- Location: Online
- Contact: > See Description for contact information
- Description: Financial Aid Services wants to remind all students to file their FAFSA! Join Financial Aid Services for FAFSA Help ZOOM Labs on Fridays from 3-4pm for help filing your FAFSA and learning more about financial aid.
Zoom link:
https://umassd.zoom.us/j/91570250746?pwd=d2NyRk9lVVg4V2krdVA2NkRBb1JYQT09
Contact Mark Yanni
myanni@umassd.edu
- Topical Areas: Students, Students, Graduate, Students, Law, Students, Undergraduate, Financial Aid
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9:00 AM
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11:00 AM
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Mechanical Engineering MS Thesis Defense by Mr. Justice Iroegbu
- Location: > See description for location
- Contact: Mechanical Engineering Department
- Description: Mechanical Engineering MS Thesis Defense by Mr. Justice Iroegbu
DATE:
May 13, 2022
TIME:
9:00 a.m. - 11:00 a.m.
ZOOM LOCATION:
https://umassd.zoom.us/j/97680493591
Meeting ID: 976 8049 3591
Passcode: 500
TOPIC:
Molecular Dynamics Simulation of the Electrode-Electrolyte Interface in Electric Double Layer Supercapacitors
ABSTRACT:
Electric double-layer supercapacitors (EDLCs) are electrochemical energy storage devices that play a major role in today's energy landscape. Compared with the mainstream lithium batteries, EDLCs offer faster charge/discharge rates and improved safety because of their energy storage mechanism. Moreover, EDLCs using solid polymer electrolytes offer the possibility to develop multifunctional structural energy storage devices. However, it has been experimentally observed that the performance dramatically decreases when we switch liquid electrolytes to solid polymer ones in EDLCs. The fundamental mechanism behind this phenomenon is difficult to characterize experimentally. In this work, we study the electrode-electrolyte interface in EDLCs using molecular dynamics (MD) simulations, which can reveal atomic behaviors that are not experimentally measurable. We construct two models with graphene electrodes and different electrolytes, including an aqueous solution-based liquid electrolyte and a polymer-based solid electrolyte. Both systems are configured to contain the same salt concentration. The modeled systems are simulated via the LAMMPS package using the NPT-NVT (equilibration and production respectively) ensemble. Molecular phenomena such as the trajectories of atoms, Inner and Outer Helmholtz Layers (IHL and OHL), ion distributions, and electrode-ion screening effect are characterized at various applied charge levels. The results show that the polymer electrolyte system exhibits an IHL similar to the one in liquid electrolyte system that has been studied in literature. It is also observed that the concentration of ions at the electrode-electrolyte interface is lower for the polymer electrolyte than for the aqueous electrolyte. In addition, the ion-electrode distance in the polymer electrolyte is greater compared to that in the aqueous one. Ionic conductivities of the two systems are determined by both experimental measurements and simulations to validate the feasibility of MD simulations. These observations give us new molecular insights to the interface of polymer electrolyte-based EDLCs.
ADVISOR:
Dr. Caiwei Shen, Assistant Professor of Mechanical Engineering, UMass Dartmouth
COMMITTEE MEMBERS:
-Dr. Jun Li, Assistant Professor of Mechanical Engineering, UMass Dartmouth
-Dr. Maricris Mayes, Associate Professor of Chemistry and Biochemistry, UMass Dartmouth
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Caiwei Shen (cshen2@umassd.edu, 508-999-8449).
- Topical Areas: Faculty, General Public, Staff and Administrators, Students, Students, Graduate, Students, Undergraduate, University Community, College of Engineering, Mechanical Engineering, Lectures and Seminars, STEM Education, STEM
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10:00 AM
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12:00 PM
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ELEE Oral Comprehensive Exam for Doctoral Candidacy by Jeffrey Rodriguez
- Location: Science and Engineering Building
, 285 Old Westport Road, Dartmouth, MA
- Cost: Free
- Contact: ECE: Electrical & Computer Engineering Department
- Description: Topic: Heterogeneously Integrated RF/Photonic Links for High Dynamic Range Receivers
Location: Science & Engineering Building (SENG), Room 212
Zoom Conference Link: https://umassd.zoom.us/j/97509003269
Meeting ID: 975 0900 3269
Passcode: 531367
Abstract:
The advantages of using optical fiber as a medium of transmission for microwave signals have led to increasing interest in the design and implementation of RF/Photonic links. Several advantages include low loss, low weight, flexibility, immunity to electro-magnetic interference (EMI), and the prospect of higher bandwidth. Using the properties of optical fiber, RF/Photonic links are capable of generating, distributing, and processing microwave signals for applications such as radar, communications, and sensors. Nonetheless, despite its advantages over traditional microwave links, RF photonic links can still suffer from poor dynamic range due to the nonlinear properties and noise contributions of devices used in the electrical-to-optical (E/O) and optical-to-electrical (O/E) conversion processes. Previous attempts to increase the dynamic range include increasing the power of the optical source, improving the photocurrent handling of the detection process, adding nonlinear RF components to the link, and complex linearization techniques to compensate for performance. To address these concerns, we propose to investigate two complementary down-conversion RF photonic link architectures: 1) Coherent phase-modulated (PM) link with an OPLL receiver, and 2) Coherent amplitude-modulated (AM) link with an optical super-heterodyne receiver. Both links will be investigated to demonstrate a RF-to-bits RF photonic receiver with high dynamic range, low noise figure and ease of fabrication. We will also consider a novel heterogenous platform that relies on the integration of semiconductor materials with lithium niobate (LiNbO3) for realizing the transmitter and receiver of the optical links.
Advisor(s): Dr. Yifei Li, Professor, Department of Electrical & Computer Engineering, UMASS Dartmouth
Committee Members:
Dr. David A. Brown, Professor, Department of Electrical & Computer Engineering, UMASS Dartmouth
Dr. Dayalan P. Kasilingam, Professor, Department of Electrical & Computer Engineering, UMASS Dartmouth
Dr. Tariq Manzur, Adjunct Professor, Department of Electrical & Computer Engineering, UMASS Dartmouth; Scientist & Engineer, Naval Undersea Warfare Center (NUWC)
Dr. Siva Yegnanarayanan, Technical Staff, MIT Lincoln Laboratory
Note: All ECE Graduate Students are ENCOURAGED to attend.
All interested parties are invited to attend. Open to the public.
*For further information, please contact Dr. Yifei Li at 508.999.8841 or via email at yifei.li@umassd.edu.
- Topical Areas: General Public, University Community, College of Engineering, Electrical and Computer Engineering, STEM
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