Events
Topic: Experimental Demonstration of Sound Source Bearing Estimation at a Single Receiver Using Spectral Cues Location: Lester W. Cory Conference Room Science & Engineering Building (SENG), Room 213A Abstract: Traditionally, bearing estimation of a sound source is accomplished by exploiting relative time differences of arrival across an array of sensors. For scenarios where arrays of sensors cannot be effectively utilized due to size or cost, an alternative method for source localization must be considered. Yovel et al. [Science, 2010] discovered one such method when observing that bats steer the main response axis (MRA) of their echolocation beams askew of a target. While this strategy reduces the SNR of a received echo, it paradoxically improves the Fisher information about a target's bearing angle. This trade-off suggests there are spectral cues which improve target localization despite the lost signal power. For a single sensor with far-field frequency-dependent directivity, and a known broadband waveform of finite temporal support and sufficient SNR, it is possible to locate a sound source by the angle-dependent lowpass filtering of the signal at the receiver. Furthermore, there exists an angle which minimizes the bearing angle estimate that is near to, but not coincident with the main response angle of the receiver. This thesis presents experiments demonstrating a man-made system estimating a source's bearing from signal spectral information using a single directional sensor with frequency dependence over the bandwidth of the received signal. A linear FM chirp from a source in the far field is recorded, measuring the beampattern of the receiver. Maximum likelihood estimates (MLE) of source bearing are calculated in a Monte Carlo algorithm, comparing noise-corrupted recordings to a randomized dictionary of template recordings. Mean-squared error (MSE) is computed as a function of source angle and compared to the Cramer-Rao lower bound (CRLB). Experimental results support that the MSE is not proportional to angle-dependent SNR, rather there are local variance minima away from the receiver MRA where the received signal power is attenuated. The MSE local minima are consistent with optimal angles observed in previous studies simulating the exploitation of spectral cues on target localization [Kloepper et al., JASA-EL 2018] [Tidwell & Buck, IEEE SSPD 2019]. Advisor(s): Dr. John R. Buck, Chancellor Professor, Department of Electrical & Computer Engineering, UMASS Dartmouth Committee Members: Dr. Dayalan P. Kasilingam, Professor, Department of Electrical & Computer Engineering, UMASS Dartmouth; Dr. Paul J. Gendron, Associate Professor, Department of Electrical & Computer Engineering, UMASS Dartmouth 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. John R. Buck email at jbuck@umassd.edu Zoom Conference Link: https://umassd.zoom.us/j/91744864902 Meeting ID: 917 4486 4902 Passcode: 844492
Department of Fisheries Oceanography "Diverse uses for Species Distribution Models (SDMs) in New England fisheries management" Michelle Bachman Lead Fishery Analyst, NEFMC Wednesday, November 27, 2024 3pm-4pm SMAST E 101-102 and via Zoom Abstract: Species Distribution Models (SDMs) combine presence / absence or relative abundance data from fishery-independent surveys with environmental data to predict the probability of marine fish and shellfish species occurrence through space and time. Using Community Basis Function Modeling techniques (Hui et al. 2023), offshore and inshore fish survey data, and a diverse suite of environmental predictors, we are estimating distributions for New England Council and Mid-Atlantic Council managed species and other abundant species in the Northeast U.S. Shelf Ecosystem. A solid understanding of current species distributions and the factors that influence them is essential to fisheries management decision-making in an era of climate change. We envision diverse applications for model outputs that aim to improve the responsiveness and resilience of fisheries management. The initial application for these model outputs is revising essential fish habitat designation maps. The Council's essential fish habitat designations support fisheries management decisions as well as consultations on non-fishing projects that are likely to impact fish habitats, and, by extension, fishery resources and fisheries. The three climate-resilience applications are: (1) identifying considerations for designating ecosystem component species in our fishery management plans, (2) developing revisions to governance approaches to account for current vs. historic species distributions, and (3) evaluating the results of portfolio analyses that will be used to identify opportunities and gaps in our management system, for example how fishing permits are structured. This talk will briefly describe our modeling approach and share how the results will be applied to each of these four projects. Potential future updates to these SDMs will also be noted. Join the Zoom Note: Meeting passcode required, email contact below to receive To request the Zoom passcode, or for any other questions, please email Callie Rumbut at c.rumbut@umassd.edu
Mechanical Engineering / Industrial & Systems Engineering (ISE) MS Project Presentation by Mr. WASEEMAKRAM MOHAMMED DATE: December 2, 2024 TIME: 2pm-4pm LOCATION: Join Zoom Meeting https://umassd.zoom.us/j/96829665890?pwd=XnPY9KQmOnsyiEqQYR1o9RP5byJsQX.1 Meeting ID: 968 2966 5890 Passcode: 977641 TOPIC: CATSED OIL SEALER BLOCK USED IN MINING EQUIPMENT WITH CAM PROFILE ABSTRACT: Casted oil sealer blocks function by creating a tight seal between moving components, preventing the leakage of lubricants. This ensures that the machinery operates efficiently by reducing friction and wear. Additionally, they help to protect internal components from contaminants like dust and debris, extending the lifespan of the equipment, which can cause costly damage to the machine. The casted oil sealer block is designed to ensure a tight seal in mining equipment, preventing oil leaks and maintaining optimal performance. Its cam profile enhances the sealing efficiency by providing a precise fit and improved durability in harsh mining conditions. Cam sealers are used to prevent dust from entering mining equipment, and over time, the frictional wear of the cam sealer can lead to a decrease in its effectiveness. It is important to monitor cam sealers for signs of frictional wear and replace them, when necessary, to maximize the effectiveness of the mining equipment. The present work focused on structural stability of cam sealer with different materials made of gravitational casting. SS316 and H13 are materials considered noncorrosive metals for many applications of mining. As we know, the lubrication can control the heat fluxes and internal temperatures of the seal body, most of the literature concentrates on the top load digging forces on the entire body. Rock digging is a different scenario, and the forces act in opposite direction. Considering these factors an increment load on the cam surface analyzed for deformed stability in profile. To avoid damage directly on base block oil injected hose the maximum load applied as 120 kg on sealer block cam profile. The materials were compared after analysis and the cost evaluation done in industrial production criteria for both the materials. ADVISOR: Dr. Wenzhen Huang, Professor, Department of Mechanical Engineering, UMass Dartmouth COMMITTEE MEMBERS: Dr. Vijaya Chalivendra, Assistant Professor, Department of Mechanical Engineering, UMass Dartmouth Dr. Md Habibor Rahman, Assistant Professor, Department of Mechanical Engineering, UMass Dartmouth Open to the public. All MNE students are encouraged to attend. For more information, please contact Dr. Wenzhen Huang (whuang@umassd.edu) or Sue Cunha (scunha@umassd.edu).
Department of Estuarine and Ocean Sciences MS Thesis Defense "A Post-Enrichment Assessment of Belowground Carbon and Organic Matter and the Potential for Increased Accumulation in a Fertilized Coastal Salt Marsh" By: Wendy Copps Co-Advisors: Miles Sundermeyer and David White Committee Member: David Schlezinger Tuesday December 3rd, 2024 11am SMAST West 204 706 S. Rodney French Blvd, New Bedford and via Zoom Abstract: Great Sippewissett Marsh in Falmouth, MA is the site of a 50-year nutrient-enrichment experiment. Experimental plots were established and fertilized with four different nutrient regimes (low, high, extra high, and no fertilization), in order to evaluate the marsh response. As a follow-up to this enrichment study, the present study was conducted to measure the amount of belowground carbon and organic matter within the experimental plots at the conclusion of the enrichment period. The goal of this study is to assess whether fertilization of the marsh facilitated increased carbon and/or organic matter accumulation in the sediments and to identify any potential relationship between the amount of fertilizer applied and the amount of carbon or organic matter stored in the sediments. The increase in the marsh surface platform is vital to maintaining the functions of the marsh as sea level rises. In a sediment-starved system such as Great Sippewissett, belowground accumulation of organic matter plays a dominant role in elevating the marsh surface platform. However, the results of this study show that higher nutrient loading does not generate more carbon or organic matter within the marsh sediments and, thus, nutrient loading is unlikely to promote elevation of the marsh surface through increased production and storage of carbon and organic matter in the sediments. Join the Zoom Note: Meeting passcode required, email contact below to receive To request the Zoom passcode, or for any other questions, please email Callie Rumbut at c.rumbut@umassd.edu
The UMassD Police Department is proud to host the 27th Annual Quarters for Christmas toy drive in the Campus Center. Food will be available to purchase, and all proceeds and donations will be used to buy toys for local children in need. New toys will also be accepted at this time. Contact: amanda.mullaly@umassd.edu
Department of Estuarine and Ocean Sciences "Biodegradation Test Methods for Polymers in the Marine Environment" Jo Ann Ratto Ross Adjunct Professor, Plastics Engineering Department, UMass Lowell Wednesday, December 4, 2024 12:30pm-1:30pm SMAST E 101-102 and via Zoom Abstract: Biodegradable polymers have historically been studied as a solution to reduce solid waste since they can decompose in soil, compost and/or the marine environment. However, biodegradation is a challenge for most polymers in the marine environment. An introduction to polymers will be presented focusing on several biodegradable polymers. A tiered approach to evaluate the biodegradation of polymers in the marine environment will also be reviewed. The Tier 1 method utilizes an optimized environment, sample preparation and conditions to evaluate biodegradation by respirometry. A Tier 2 test uses weight loss as a function of time to evaluate actual items in the marine environment, and a Tier 3 test has items positioned in the deep sea for weight loss studies. Overall, this Tier 1 approach is a valuable screening method for polymers while Tiers 2 and 3 are real-life test methods for determining the fate of polymers in the marine environment. Toxicity as well as disintegration tests are also important when studying polymers in the marine environment. Sample data and results will be shown for a variety of materials. Join the Zoom https://umassd.zoom.us/j/97440069270 Note: Meeting passcode required, email contact below to receive To request the Zoom passcode, or for any other questions, please email Callie Rumbut at c.rumbut@umassd.edu
Join the Green Navigators in clearing the brush and overgrowth trails on campus! Please check the address notes for the location. Gloves and equipment will be provided. It is recommended that participants wear long pants, long sleeves, or a sweatshirt, and at minimum close-toed shoes, as well as bring water. Sticker(s) Available: Trail Clearing Contact bbarreraguerrero@umassd.edu for meet-up times and locations.
TIME CHANGE Mechanical Engineering MS Project Presentation by Mr. Adam Fiore DATE: December 6, 2024 TIME: 9:30am-11pm LOCATION: Science & Engineering (SENG), Room 110 (Materials Science Lab) TOPIC: Engine Bay Thermal Analysis of a Medium Class Unmanned Surface Vessel ABSTRACT: An unmanned surface vessel has the capability of operating remotely, semi-remotely, or fully autonomously (conducting missions without human intervention), while being equipped with advanced sensors and payloads for intelligence, surveillance and reconnaissance (ISR). Operating without personnel onboard demands the need to identify the possibility of system component failures that may occur due to out-of-operating range temperatures. In this project, a thermal finite element analysis (FEA) and computational fluid dynamics (CFD) shall be conducted on a medium class unmanned surface vessel, provided by the project's sponsors Huntington Ingalls Industries Uncrewed Systems Division (UxS). These studies consider both the vessel traversing the ocean at a maximum speed of 40 knots for a time duration of 10 and 4 hours and the vessel stationary at a pier during two extreme environmental conditions. These extreme environments include ambient temperatures of 115F and -20F and seawater conditions of 95F and 31F. With the vessel's internal engine bay and components being the largest source of generated heat, this shall be the interest of this project. The analysis in SOLIDWORKS models the temperature and heat transfer between components and flags minimum and maximum temperature conditions and locations. All while simulating variable environmental and system boundary conditions. A final report summarizing the results within the engine bay was provided to the project's sponsors, UxS, and included in this project. A standard operating procedure (SOP) of thermal FEA/CFD practices in SOLIDWORKS was provided to the company to apply the same methods on all system components of the MUSV. Areas of future design improvements of the MUSV are discussed briefly, Finally, future studies to better understand the effects of system components on the MUSV that contribute to high temperature changes within the engine bay are discussed. ADVISOR: Dr. Sankha Bhowmick, Professor/Chairperson, Department of Mechanical Engineering, UMass Dartmouth COMMITTEE MEMBERS: Dr. Hangjian Ling, Assistant Professor, Department of Mechanical Engineering, UMass Dartmouth Mr. James LaCroix, HII Corporate Director, Huntington Ingalls Industries (HII) Open to the public. All MNE students are encouraged to attend. For more information, please contact Dr. Sankha Bhowmick (sbhowmick@umassd.edu).
Join us at UMass Law for an engaging Open House, where you'll get a comprehensive look at our programs, campus, and community. This event offers a unique opportunity to connect with our dedicated faculty, interact with current students, and learn about our mission to advance justice through a rigorous yet supportive program. Take the first step toward your legal education with UMass Law! Register here: https://www.umassd.edu/law/open-house/ For questions, please contact the Law Admissions Office at law@admissions.umassd.edu or 508-985-1110.
EAS Doctoral Dissertation Defense by Soolmaz Khoshkalam Date: Friday,December 13, 2024 Time: 9:00 a.m. Topic: Potential of Mean Force-Based Lattice Element: Extension to Dynamic and Nonlinear Analysis of Structures Location: LIB 314 Abstract: The potential-of-mean-force (PMF) approach to the lattice element method (LEM) has recently been adapted to model the response of structural systems. LEM relies on lattice discretization of the domain via a set of particles that interact through prescribed potential functions, representing the mechanical properties of members. The approach offers unique advantages, including robustness to discontinuity and failure without the need for mesh refinement. The overall goal of this research is two-fold: (i) extend the quasi-static PMF-based LEM to model the dynamic behavior of structures (ii) blend the quasi-static PMF-based LEM with Force Analogy method for nonlinear analysis. Such developments provide a means for simulating nonlinear response and failure under dynamic loading that is the nature of most natural hazards and extreme conditions. To accomplish the first goal, integration methods from Molecular Dynamics (MD) are used to estimate of the trajectory of particles in the Lattice Element Method (LEM) and to simulate the dynamic response with a focus on structural (or building) systems. More specifically Verlet-Velocity method is used to estimate the location and momentum of each particle at every time step. To assure accuracy and the numerical stability, we also explore implicit integration techniques such as Hilber-Hughes-Taylor method and midpoint method. Noting that the rotational degrees of freedom have minimal contribution to the kinetic energy of the system we develop an energy-based approach for condensation to reduce the computational cost. Our approach relies on the Euler-Lagrange equations and manifests itself in the form of minimum potential energy theorem for mass-less degrees of freedom. To address another critical aspect of dynamic simulation, the mass matrix, we adopt an energy-based approach and utilize the kinetic energy of the lattice elements to maintain consistency with the kinetic energy of their continuous counterparts. To achieve the second goal, we incorporate the nonlinear behavior of materials under various actions, including bending, torsion, and axial forces, through the introduction of novel potential functions inspired by the Force Analogy Method. These potential functions are calibrated using section properties that represent the nonlinear stress-strain responses of materials, such as nonlinear moment-curvature relationships. The utility of the proposed framework and its and accuracy are validated through its application in quasi-static linear and nonlinear simulations of large-scale buildings subjected to different loading conditions. ADVISOR(S): Dr. Mazdak Tootkaboni, Dept of Civil and Environmental Engineering (Advisor) (mtootkaboni@umassd.edu) Dr. Arghavan Louhghalam, Dept. of Civil and Environmental Engineering (Co-Advisor) (Arghavan_Louhghalam@uml.edu) COMMITTEE MEMBERS: Dr. Alfa Heryudono, Department of Mathematics and Dr. Zheng Chen, Department of Mathematics NOTE: All EAS Students are ENCOURAGED to attend.
EAS Doctoral Proposal Defense by Zhuoyuan Leng Date: Tuesday, December 17, 2024 Time: 10:00am Topic: Experimental and Numerical Studies on Mixed-mode Fracture of Additively Manufactured Polymer Nanocomposites Location: LIB 314 Zoom Link: https://umassd.zoom.us/j/92967323046?pwd=ppH0sI5z79H46F0rQhSkb2S4Y16mlA.1 Abstract: This study investigates the mixed-mode fracture behavior of ABS nanocomposites fabricated using fused deposition modeling (FDM) for automotive and aerospace applications. The scope includes quasi-static and dynamic mixed-mode fracture scenarios, and cyclic mixed-mode fatigue fracture properties, using experimental and numerical methods, focusing on understanding crack dynamics and enhancing the fracture toughness of ABS composites. It explores fracture criteria under mixed mode loading conditions and assesses the influence of printing direction, loading type, and nanoparticle weight percentage. The experimental methodology is divided into three parts: (1) quasi-static mixed-mode loading of ABS nanocomposites with different printing directions, (2) dynamic mixed-mode loading using a modified Hopkinson pressure bar setup, and (3) cyclic fatigue loading to assess fatigue fracture performance. Scanning electron microscopy (SEM) will be used to analyze fracture surfaces and correlate them to fracture mechanisms under various mode-mixities and loading conditions. Simulation studies focus on crack dynamics using the phase-field method (PF) implemented in COMSOL, with anisotropic material formulations to model different printing directions and dynamic loading scenarios. Comparisons between simulations and experiments will enhance the understanding of fracture mechanisms. The outcome can be used to optimize ABS nanocomposite performance and provide insights for structural applications. ADVISOR(S): Dr. Vijaya Chalivendra, Department of Mechanical Engineering (vchalivendra@umassd.edu) COMMITTEE MEMBERS: Dr. Caiwei Shen, Department of Mechanical Engineering Dr. Jay Wang, Department of Physics Dr. Jun Li, Research Associate Professor, ERAU NOTE: All EAS Students are ENCOURAGED to attend.
Observatory Open House No moon - lots of planets, Orion Nebula, etc.