Title: A Probabilistic Risk Assessment Based Approach to Understanding and Managing the Risks of Natural Gas Distribution Piping in the United States
Author: Sara Lyons
Committee Members:
Dr. Mohammad Modarres (Chair),
Dr. Katrina Groth,
Dr. Jeffrey Herrmann
Date & Time: Fri May 22, 2020 1pm – 2:45pm Eastern Time
Abstract: Two hundred sixty-nine regulated pipeline system accidents caused fatalities and/or injuries in the United States between 2010 and 2018, resulting in 106 fatalities and 599 injuries requiring hospitalization. About 84% of these serious accidents occurred on gas distribution systems, which primarily transport natural gas. This study utilizes probabilistic risk assessment (PRA) methods, nationwide gas distribution system information, and operator reported accident data to evaluate natural gas distribution system risks, estimate how many additional resources the public would be willing to dedicate to reduce or eliminate these risks, and determine which improvement areas warrant further evaluation. Recommendations regarding the overall PRA-based framework, as well as the scope, quality, and level of detail of the underlying data, are provided.
This month’s issue of AcademicKeys’ e-Flier for Engineering features 53 higher education positions in Mechanical Engineering, Engineering Physics, Engineering Mechanics, and more. Please visit the AcademicKeys Website for more information and application procedures.
The American Association for the Advancement of Science (AAAS) has updated its May 2020 Science Magazine, which features job opportunities, career articles, tips, etc. Below is a snapshot of a few of the job opportunities that the website offers. Please be sure to visit the website to learn more!
Title:Cost-effective Prognostics and Health Monitoring of Locally Damaged Pipelines with High Confidence Level
Committee Members:
Dr. Mohammad Modarres, Advisor and Chair. Dr. Shapour Azarm, Co-advisor Dr. Balakumar Balachandran
Dr. Mark Fuge Dr. Katrina Groth Dr. Kayo Ide, Dean’s Representative Dr. Vasiliy Krivtso
Date & Time: Friday, June 5, 2020. 2:00-4:00 PM
Abstract: Localized pipeline damages, caused by degradation processes such as corrosion, are prominent, can result in pipeline failure and are expensive to monitor. To prevent pipeline failure, many Prognostics and Health Monitoring (PHM) approaches have been developed in which sensor network for online, and human inspection for offline data gathering are separately used. In this dissertation, a two-level (segment- and integrated-level) PHM approach for locally damaged pipelines is proposed where both of these degradation data gathering schemes (i.e., detection methods) are considered simultaneously. The segment-level approach, in which the damage behavior is considered to be uniform, consists of a static and a dynamic phase. In the static phase, a new optimization problem for health monitoring layout design of locally damaged pipelines is formulated. The solution to this problem is an optimal configuration (or layout) of degradation detection methods with a minimized health monitoring cost and a maximized likelihood of damage detection. In the dynamic phase, considering the optimal layout, an online fusion of high-frequency sensors data and low-frequency inspection information is conducted to estimate and then update the pipeline’s Remaining Useful Life (RUL) estimate. Subsequently, the segment-level optimization formulation is modified to improve its scalability and facilitate updating layouts considering the online RUL estimates. Finally, at the integrated-level, the modified segment-level approach is used along with Stochastic Dynamic Programming (SDP) to produce an optimal set of layouts for a long pipeline consisting of multiple segments with different damage behavior.
Experimental data and several notional examples are used to demonstrate the performance of the proposed approaches. Synthetically generated damage data are used in two examples to demonstrate that the proposed segment-level layout optimization approach results in a more robust solution compared to single-detection approaches and deterministic methods. For the dynamic segment-level phase, acoustic emission sensor signals and microscopic images from a set of fatigue crack experiments are considered to show that combining sensor- and image-based damage size estimates leads to accuracy improvements in RUL estimation. Lastly, using synthetically generated damage data for three hypothetical pipeline segments, it is shown that the constructed integrated-level approach provides an optimal set of layouts for several pipeline segments.
Title:Design and Analysis of a Novel, Ultra-Light, Cyrogenic Dewar for Balloon-Borne Observatories
Author: Samuel Denker
Date & Time: May 26, 2020 03:00 PM Eastern Time (US and Canada)
Committee: Professor Marino DiMarzo, Chair Professor Jungho Kim Research Professor Yunho Hwang Dr. Alan Kogut (outside scientist)
Abstract: The deployment of cryogenic Dewars aboard high-altitude balloons is critical to astronomical observation at sub-millimeter wavelengths. Balloon-borne, cryogenically cooled telescopes are limited in size by weight restrictions of the balloons, which is dominated by the Dewars. This thesis presents a portion of the multi-phase BOBCAT project which reduces Dewar weight with the use of thin-walled designs and a novel multi-layer insulation (MLI) system. The BOBCAT-1 mission used conventional Dewar technology to demonstrate cryogen transfer at float altitude and establish baseline thermal performance of balloon-borne Dewars. Design and assembly of the BOBCAT-2 ultra-light Dewar showed successful fabrication of the thin-walled vessel and novel MLI system. Thermal modeling predicts that the BOBCAT-2 Dewar will experience an order of magnitude increase in heat transfer through the MLI, equivalent to a 60% increase through the Dewar in total, due to its larger volume and decreased number of radiation shields relative to the BOBCAT-1 Dewar.
AKATECH has updated their database some of the current job openings across the globe in the field of Computer Science and Engineering. For more information on these postings, click here.
In order to keep you all posted on announcements and to answer any questions, meGRAD will be hosting a Town Hall on Friday May 8th from 1-2PM. We will be making general announcements, policy updates, deadlines, etc. There will also be a Q&A session for students to ask any important questions. The Q&A session will be monitored by staff.
We ask that participants mute their devices when not speaking. Any questions or concerns you have during the meeting should be posted in the chat box. We will attempt to answer all questions within the time limit, but this is not guaranteed. If your question is missed during the town hall, we will follow up with you directly. If you would like to submit any questions in advance, please send them directly to Darius Craig (dcraig12@umd.edu).
Immediately following the Town Hall, we will be posting meGRAD’s Spring 2020 Virtual Award Ceremony. During this ceremony, we will honor the achievements and accomplishments of meGRAD’s amazing students. Although we cannot meet in person, meGRAD is working tirelessly to ensure that you all are recognized for your hard work and dedication. If you would like to be recognized for an award or achievement, contact Darius at dcraig12@umd.edu by Noon, May 7th.
Title: Mixed Complementarity Modeling in the Global Natural Gas Market
Author:Justin (Chad) Huemme
Date & Time:Monday, May 11, 2020 – 12:00PM
Committee
Professor Steven Gabriel, Chair/Advisor
Professor Shapour Azarm
Associate Professor Qingbin Cui
Abstract:This thesis describes the development and capabilities of an updated mixed complementarity problem model of the global natural gas market derived from the University of Maryland 2014 World Gas Model (WGM). Through an understanding of the current state of the natural gas market, the WGM determines the economic behavior of various market players with the deployment of Karush-Kuhn-Tucker (KKT) optimality conditions in conjunction with market-clearing conditions. The capabilities of the World Gas Model are highlighted through two case studies that are of varying international importance. The case studies are specifically selected from different issues that face the natural gas market such as a United States and China trade war and U.S. Coast Guard liquefied natural gas (LNG) inspection workforce forecasting. The goal of the United States and China Trade War case study is to analyze the potential long- and short-term effects of a prolonged trade war under several different possible scenarios. The U.S. Coast Guard LNG inspection workforce forecasting case study utilizes the WGM to provide the future workforce demand for U.S. regulatory personnel and the associated costs based on the growth of the U.S. LNG industry.
Title: Co-design for Multi-subsystem and Vehicle Routing-and-Control Problems
Author: Tianchen Liu
Date & Time:Friday, May 15, 2020 – 2:00PM.
Committee:
Professor Shapour Azarm, Chair/Advisor
Professor Nikhil Chopra, Co-advisor
Professor Balakumar Balachandran
Professor Jin-Oh Hahn
Professor Nuno Martins
Professor Miao Yu
Abstract:Co-design refers to the process of integrating optimization of the physical design with a controller for a system. The challenge in co-design is that the optimization is simultaneously applied to both time-invariant (design) and time-variant (state and control) variables, which can be coupled with each other.
The objective of this dissertation is to explore new formulations and approaches in co-design for multi-subsystem and vehicle routing-and-control problems. Specically, four research questions are considered and resolved. In Research Question 1 (RQ1), the critical issue is how to formulate a class of multi-subsystem co-design problems with convexphysical design subproblems and linear quadratic regulator control subproblems, and construct a decentralized solution approach for such problems. In Research Question 2 (RQ2), solution methods for a broader class of multi-subsystem co-design problems than those considered in RQ1 are investigated. In Research Question 3 (RQ3), the question is whether, in the context of co-design, the combined routing and control costs of a feet of vehicles can be improved if optimal control is introduced into the routing. Finally, an extension of RQ3 is considered in Research Question 4 (RQ4), where the possibility of constructing an integrated vehicle routing-and-control problem with load-dependent dynamics is investigated.
Beyond the articles published by the author of this dissertation, the proposed research questions, models and methods presented have not been considered elsewhere in the literature.
Title: “Energy Audit and Modeling of High Energy-consuming Buildings in the University of Maryland.”
Date/Time: Friday May 8, 2020; 3-5pm
Committee Members:
Dr. Michael Ohadi (Chair),
Dr. Yunho Hwang,
Dr. Bao Yang
Abstract: The goal of this thesis project is to analyze and optimize energy usage in the Biopsychology building and Gossett Football House building. Both buildings are located on the campus of the University of Maryland, College Park. The process of energy audit and modeling was applied to both buildings to render them more energy-efficient and sustainable. The first step of the project included a comprehensive study of the buildings including the HVAC systems and other loads, followed by energy consumption analysis which led to the detection of various issues. The second step was to model the energy system of the building and analyze it to optimize the energy consumption of the building. Several benchmarking methods were also analyzed to evaluate building performance. Using the developed 3D model, the performances of the buildings were simulated to determine various Energy Conservation Measures. The Energy Conservation Measures were detected, researched in detail, and simulated to evaluate the possible savings in energy and utilities. Projected savings of $99,920 and 3,843.3 MMBtu per annum were projected for the two buildings. In addition to the energy savings, a total of 511.3 MT per annum CO2 emission reductions and 787,290-gal water savings were estimated, which can both contribute to the Campus sustainability goals.
