UMBC Mechanical Engineering Department

Permanent URI for this collectionhttp://hdl.handle.net/11603/52

Mechanical Engineering is one of the oldest and broadest engineering disciplines. In the more traditional sense, Mechanical Engineering employs principles of physics and chemistry and knowledge from the fields of mathematics, mechanics and materials science for the analysis, design, manufacturing and maintenance of mechanical systems. Again, in the traditional sense, a Mechanical Engineer would be the expert in the production and usage of heat and mechanical power which are critical in the design, production and operation of tools, components and machines used in manufacturing durable goods and in using advanced technologies for the benefit of society.

In recent years, the discipline of Mechanical Engineering has taken on an expansive, and critical role in the advancement of transformative new technologies such as the information-, bio-, nano-technologies and MEMS (Micro-Electro-Mechanical Systems). It is clearly a new and exciting world out there. We are delighted to be at the forefront of acquiring new knowledge through cutting edge research in this new and expansive field of Mechanical Engineering. As reflected in their posted profiles and accomplishments, our faculty are recognized nationally and internationally for their research and discoveries. Many of them are Fellows of engineering societies and recipients of prestigious research awards granted for excellence by agencies such as the National Science Foundation and the National Institutes of Health.

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Delivery of Tempol from Polyurethane Nanocapsules to Address Oxidative Stress Post-Injury
(ACS, 2025-02-19) Ale, Temitope; Ale, Tolulope; Baker, Kimberly J.; Zuniga, Kameel M.; Hutcheson, Jack; Lavik, Erin
Traumatic brain injuries (TBIs) result in significant morbidity and mortality due to the cascade of secondary injuries involving oxidative stress and neuroinflammation. The development of effective therapeutic strategies to mitigate these effects is critical. This study explores the fabrication and characterization of polyurethane nanocapsules for the sustained delivery of Tempol, a potent antioxidant. The nanocapsules were designed to extend the release of Tempol over a 30-day period, addressing the prolonged oxidative stress observed post-TBI. Tempol-loaded polyurethane nanocapsules were synthesized using interfacial polymerization and nanoemulsion techniques. Two generations of nanocapsules were produced, differing in Tempol loading and PEGylation levels. The first generation, with lower Tempol loading, exhibited an average size of 159.8 � 12.61 nm and a Z-average diameter of 771.9 � 87.95 nm. The second generation, with higher Tempol loading, showed an average size of 141.4 � 6.13 nm and a Z-average diameter of 560.7 � 171.1 nm. The zeta potentials were ?18.9 � 5.02 mV and ?11.9 � 3.54 mV for the first and second generations, respectively. Both generations demonstrated the presence of urethane linkages, confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Loading studies revealed Tempol concentrations of 61.94 � 3.04 ?g/mg for the first generation and 77.61 � 3.04 ?g/mg for the second generation nanocapsules. Release profiles indicated an initial burst followed by a sustained, nearly linear release over 30 days. The higher PEGylation in the second generation nanocapsules is advantageous for intravenous administration, potentially enhancing their therapeutic efficacy in TBI treatment. This study demonstrates the feasibility of using polyurethane nanocapsules for the prolonged delivery of Tempol, offering a promising approach to manage oxidative stress and improve outcomes in TBI patients. Future work will include testing these nanocapsules in vivo to determine their potential at modulating recovery from TBI.
Supporting Campus Activism through Creating DIY-AT in a Social Justice Aligned Makerspace
(ACM, 2025-01-31) Higgins, Erin; Oliver, Zaria; Hamidi, Foad
Utilizing digital fabrication methods (e.g., 3D printing) has exciting implications for the design and production of customized assistive technology (AT). However, utilizing these tools currently requires a high level of technical expertise as well as time and money investments. Furthermore, facilitating collaboration between end users and makers needs effective and inclusive approaches with shared language and support for asynchronous, dispersed communication of design requirements. While these Do-It-Yourself (DIY) approaches are shown to support end-user agency and furthering technology democratization, research has to yet explore how they can further align with social justice values and practices. We explored these possibilities by facilitating DIY-AT design with students with disabilities, activist staff members, and community members within a university makerspace. By explicitly encouraging participants to consider social justice issues important to them as they engaged in DIY-AT design, we studied the considerations and supports needed for facilitating flexible co-design activities and broader conversations about accessibility barriers at the university. Adopting a transdisciplinary approach, we offer lessons learned about the potential of co-designing DIY-ATs as a way to investigate questions of social justice, inclusion, and access in academic contexts. We show how these created DIY-ATs can be leveraged by students and staff as tangible artifacts to encourage more funding and support from university administration for accessibility initiatives.
Polyurethane Nanocapsules Incorporating Epigallocatechin Gallate, A Green Tea Extract
(Wiley, 2025-02-26) Ale, Temitope; Ghunney, Nhyira; Pandala, Narendra; Tucker, Budd; McFadden, Kassandra; Hutcheson, Jack; Lavik, Erin
Explosions cause 79% of combat-related injuries, often leading to traumatic brain injury (TBI) and hemorrhage. Epigallocatechin gallate (EGCG), a green tea polyphenol, aids neuroprotection and wound healing. In this work, we sought to investigate the fabrication and characterization of polyurethane nanocapsules encapsulating EGCG, demonstrating controlled, on-demand release, and highlighting their potential for targeted therapeutic delivery in trauma care.
Neural network-based surrogate model in postprocessing of topology optimized structures
(Springer Nature, 2025-02-28) Persia, Jude Thaddeus; Kyun Sung, Myung; Lee, Soobum; Burns, Devin E.
This paper proposes a general method of creating an accurate neural network-based surrogate model for postprocessing a topologically optimized structure. When topology optimization results are converted into computer-aided design (CAD) files with smooth boundaries for manufacturability, finite element method (FEM) based stresses often do not agree with the topology optimized results due to changes of surface and mesh density. The conversion between topology optimization derived results and CAD files often requires postprocessing, an additional fine tuning of the geometry parameters to reconcile the change of the stress values. In this work, a feedforward, deep artificial neural network (DANN) is presented with varying architecture parameters that are found for each stress output of interest. This network is trained with the data based on a combination of Design of Experiments (DoE) models that have the geometry dimensions as inputs and stress readings under various loads as the outputs. A DANN-based surrogate model is constructed to enable fine tuning of all relevant stress performance metrics. This method of constructing an artificial network-based surrogate model minimizes the number of FEM computations required to generate an optimized, post-processed design. We present a case study of postprocessing a wind tunnel balance, a measurement device that yields the six force and moment components of a test aircraft. It needs to be designed considering multiple stress measures under combinations of the six loading conditions. Excellent performance of a neural network is presented in this paper in terms of accurate prediction of the highly nonlinear stresses under combinations of the six loads. Von Mises stress predictions are within 10% and axial force sensor stress predictions are within 2% for the final post-processed topology. The results support its usefulness for postprocessing of topology optimized structures.
Freestream turbulence effects on low Reynolds number NACA 0012 airfoil laminar separation bubble and lift generation
(2024-06-01) Yu, Meilin ; Hrynuk, John T.; Booth, David T.; Poudel, Naresh
Laminar separation bubbles (LSB's) over the suction surface of a wing at low Reynolds number (O(10⁴) - O(10⁶) based on the airfoil chord length) can significantly affect the aerodynamic performance of the wing, and pose a unique challenge for the predictive capabilities of simulation tools due to their high sensitivity to flow environments and wing surface conditions. In this work a series of two-dimensional (2D) and three-dimensional (3D) low-order, and high-order accurate unstructured-grid-based numerical methods with varying model fidelity levels were used to study LSB physics over a NACA 0012 airfoil both in a clean freestream and in a turbulent freestream at a chord-based Reynolds number of 12,000. Lift production and time-averaged flow fields were compared with available experimental results. A major discovery is that in clean freestream flow a 3D high-order numerical scheme is necessary to capture LSB physics. This is due to the sensitivity of LSB-induced laminar-turbulent transition to flow conditions and boundary geometry at low Reynolds number. In freestream flows with moderate background turbulence (~5%), 2D simulations failed to capture subtle 3D flow physics due to their intrinsic limitation, but can reasonably predict time-averaged airfoil performance. Similarity and distinction between freestream vortex-LSB interaction in 2D and eddy-LSB interaction in 3D were explained. The role of the Kelvin-Helmholtz instability and Klebanoff modes in the transition of 3D airfoils were shown to be critical for understanding laminar-turbulent transition and LSB formation on airfoils in clean and turbulent freestreams.
Supporting Campus Activism through Creating DIY-AT in a Social Justice Aligned Makerspace
(ACM, 2025-01-31) Higgins, Erin; Oliver, Zaria; Hamidi, Foad
Utilizing digital fabrication methods (e.g., 3D printing) has exciting implications for the design and production of customized assistive technology (AT). However, utilizing these tools currently requires a high level of technical expertise as well as time and money investments. Furthermore, facilitating collaboration between end users and makers needs effective and inclusive approaches with shared language and support for asynchronous, dispersed communication of design requirements. While these Do-It-Yourself (DIY) approaches are shown to support end-user agency and furthering technology democratization, research has to yet explore how they can further align with social justice values and practices. We explored these possibilities by facilitating DIY-AT design with students with disabilities, activist staff members, and community members within a university makerspace. By explicitly encouraging participants to consider social justice issues important to them as they engaged in DIY-AT design, we studied the considerations and supports needed for facilitating flexible co-design activities and broader conversations about accessibility barriers at the university. Adopting a transdisciplinary approach, we offer lessons learned about the potential of co-designing DIY-ATs as a way to investigate questions of social justice, inclusion, and access in academic contexts. We show how these created DIY-ATs can be leveraged by students and staff as tangible artifacts to encourage more funding and support from university administration for accessibility initiatives.
Investigation of Solid Fuel Ramjets Using Analytical Theory and Computational Fluid Dynamics
(2025-01-03) Khokhar, Gohar T.; McBeth, Joshua; Hanquist, Kyle M.; Oveissi, Parham; Goel, Ankit
This paper investigates the modeling and analysis of a solid-fuel ramjet (SFRJ) using analytical theory and computational fluid dynamics (CFD). The primary objectives of this study are to first apply analytical theories of an SFRJ in combination with combustion physics from NASA CEA software to establish a foundation for analytically modeling the thrust of an SFRJ with a specified bypass ratio. Secondly, this study aims to model the thrust output of an SFRJ using a simplified backward-facing step computational model consisting of a single inlet and outlet through computational analysis. In the computational model, combustion is modeled as wall heat addition, and thermal choking effects leading to engine unstart conditions are predicted. While there are more complex SFRJ modeling approaches, consideration of computational cost is an important aspect of this work, since these models will be coupled with a control system. This research serves as a foundational step in a broader investigation aimed at coupling SFRJ thrust dynamics with control systems for regulating thrust under uncertain operating conditions.
Learning-Based Thrust Regulation of Solid-Fuel Ramjet in Flight Conditions
(2025-01-03) Oveissi, Parham; Dorsey, Alex; McBeth, Joshua; Hanquist, Kyle M.; Goel, Ankit
This paper investigates the performance of a learning-based control system for regulating the thrust generated by a solid fuel ramjet engine in realistic flight scenarios. An integrated simulation framework is developed that combines a longitudinal missile dynamics model, a missile autopilot, a quasi-static engine dynamics model, and a learning controller for thrust regulation. The missile autopilot is based on the classical three-loop topology. The learning controller is an adaptive PID controller whose gains are recursively optimized using the retrospective cost adaptive control algorithm. First, harmonic acceleration commands are used to simulate variable flight conditions that affect the thrust generated by the engine model. Next, an interception scenario is simulated by integrating a guidance law in the loop. Numerical results indicate that the learning controller can regulate the generated thrust despite wide variations in operating conditions.
Adaptive Numerical Differentiation for Extremum Seeking with Sensor Noise
(2025-01-08) Verma, Shashank; Salazar, Juan Augusto Paredes; Delgado, Jhon Manuel Portella; Goel, Ankit; Bernstein, Dennis S.
Extremum-seeking control (ESC) is widely used to optimize performance when the system dynamics are uncertain. However, sensitivity to sensor noise is an important issue in ESC implementation due to the use of high-pass filters or gradient estimators. To reduce the sensitivity of ESC to noise, this paper investigates the use of adaptive input and state estimation (AISE) for numerical differentiation. In particular, this paper develops extremum-seeking control with adaptive input and state estimation (ESC/AISE), where the high-pass filter of ESC is replaced by AISE to improve performance under sensor noise. The effectiveness of ESC/AISE is illustrated via numerical examples.
Adaptive Combustion Regulation in High-Fidelity Computational Model of Solid Fuel Ramjet
(2025-01-03) Oveissi, Parham; Dorsey, Alex; Khokhar, Gohar T.; Hanquist, Kyle M.; Goel, Ankit
Controlling the combustion process under hypersonic conditions remains a significant challenge. This paper uses a data-driven, learning-based control technique to regulate the combustion process within a solid fuel ramjet, aiming to regulate the generated thrust under uncertain operating conditions. A high-fidelity computational model combining compressible flow theory with equilibrium chemistry is developed to simulate combustion dynamics. This model evaluates the stability of the combustion dynamics and defines the engine’s operational envelope. An online learning controller based on retrospective cost optimization is integrated with the computational model to regulate the thrust. Numerical simulations indicate that the learning control system can regulate the thrust generated by an SFRJ without requiring any modeling information.
Comparison of Several Neural Network-Enhanced Sub-Grid Scale Stress Models for Meso-Scale Hurricane Boundary Layer Flow Simulation
(AIAA, 2025-01-03) Hasan, MD Badrul; Yu, Meilin; Oates, Tim
The complicated energy cascade and backscatter dynamics present a challenge when studying turbulent flows in storms at the meso-scale. When performing standard large-eddy simulations (LES), sub-grid scale (SGS) stress models usually fail to consider energy backscatter. These models assume that kinetic energy only moves continuously from larger to smaller scales. However, coherent energy backscatter structures exist when analyzing hurricane boundary layer flows at the meso-scale. Our recent research has shown that machine-learning SGS models trained with high-resolution data can effectively forecast forward and backward energy transfers in meso-scale hurricane-like vortex flows. Therein, physical and geometrical invariances were introduced to better represent flow physics. This further improved the predictability and generalizability of machine-learning-enhanced SGS models. In this study, we compare the performance of several machine-learning-enhanced SGS models, especially those based on neural networks (NNs), with varying physical and geometrical invariance embedding levels for SGS stress modeling in an a priori sense, which sets the cornerstone for ongoing a posteriori tests of NN models.
FINITE ELEMENT ANALYSIS OF A THREE-STAGE 3D PRINTED TENSEGRITY ICOSAHEDRON STRUCTURE
(2024-01-01) Bharata, Abhinav; Zhu, Weidong; Mechanical Engineering; Engineering, Mechanical
Tensegrity is a crucial factor in the progress of humanity in various domains, including architecture and biology. This work is centered on the tensegrity structure of an icosahedron configuration, which is also referred to as a diamond tensegrity. This structure consists of six bars in each stage, with four strings linked to each end of the bar, forming a diamond shape. A three-stage tensegrity-icosahedron (T-Icosahedron) structure, composed of 3D printed components, was studied. The entire structure contains a total of 72 strings and 18 bars manufactured from Ninja Flex and Polylactic acid material. A novel vibration-based method was developed to measure tensions in the strings in the structure. A Polytec laser vibrometer was utilized to accurately measure the tensions and calibrate the nodal coordinates of the structure. The study subsequently focuses on a finite element analysis technique to examine the natural frequencies of the structure and generate its mode shapes using MATLAB. The obtained results are then compared with those obtained from the commercial finite element program ANSYS. This work provides a thorough examination of the T-Icosahedron structure, as well as potential opportunities for additional investigation involving alterations in geometry and material composition of the structure.
Development of a Novel General-purpose Three-dimensional Continuously Scanning Laser Doppler Vibrometer System
(2024-01-01) Yuan, Ke; Zhu, Weidong; Mechanical Engineering; Engineering, Mechanical
The objective of this work is to develop a novel general-purpose three-dimensional (3D) continuously scanning laser Doppler vibrometer (CSLDV) system for 3D vibration measurement of structures with arbitrarily curved surfaces. This work is motivated by the fact that 3D full-field vibration measurement is significant to structures, especially those with curved and complex surfaces such as turbine blades, vehicle bodies, and aircraft wings. Modal tests that obtain vibration components along three axes of a coordinate system can provide more information and locate defects on more complex structures than those that only obtain single-axis vibration, and can improve the accuracy of their structural health monitoring. 3D full-field vibration can also be used to identify dynamic characteristics of a complex structure and update its finite element model during structural analysis and product design where vibration must be determined in all its components. A triaxial accelerometer can be attached on a structure to measure its 3D vibrations, which can lead to mass loading, especially when multiple triaxial accelerometers are needed in modal tests of light-weight structures. A 3D scanning laser Doppler vibrometer (SLDV) system can be used to measure 3D vibration of a structure in a non-contact. However, it usually takes the 3D SLDV system a long time to obtain high spatial resolution, especially for structures with large surfaces, because laser spots must stay at one measurement point for enough time before they are moved to the next one to conduct more averages of measurement data when high frequency resolution is needed. The 3D CSLDV system proposed in this work can rapidly obtain 3D full-field vibration shapes, such as mode shapes and operating deflection shapes (ODSs) of a structure, in a non-contact way by sweeping three laser spots over its surface in a continuous and synchronous mode. The universality of the system lies in its capability to measure vibration of structures with various shapes, including flat, curved, and difficult-to-access areas, as well as structures under various excitation, including sinusoidal and random excitation. The major contributions of this work include: 1) developing a calibration method to achieve synchronous scanning of three laser spots, and improving it to fit measurement on curved surfaces and virtual surfaces behind a mirror; and 2) developing a signal processing method to identify modal parameters of structures under random excitation.
Broadband Energy Harvester for Tram Vibration Utilizing a 2-DOF Mass-Spring-Damper System
(2024-01-01) Umar, Hamza; Lee, Soobum; Mechanical Engineering; Engineering, Mechanical
This thesis presents a broadband vibrational energy harvesting device that utilizes a varied frequency from a tram using a 2-degree-of-freedom vibrational system combined with electromagnetic energy conversion. This paper will compare the power output for two design configurations of 2-DOF systems: open-end and closed-end designs. A stepwise optimization process is applied to determine (1) mechanical parameters for frequency tuning to adjust to the trams’ operational conditions, and (2) electromagnetic parameters for the whole system design to maximize power output. The 1st step will determine mechanical design parameters for frequency tuning: masses (mi) and spring constants (ki). The 2nd step will use these parameters as initial guesses and present electrical parameters and damping coefficients (ci) to maximize the power output in the frequency band of interest. The design results indicate that the closed-end design has a preferable performance, compared to the open-end design, in terms of broadband vibration energy harvesting with higher average power as well as manufacturability within design constraints.
Novel Image-based Tracking Continuously Scanning Laser Doppler Vibrometer Systems for Vibration Measurement of Rotating Wind Turbine Blades
(2024-01-01) Lyu, Linfeng; Zhu, Weidong; Mechanical Engineering; Engineering, Mechanical
The objective of the proposed research is to develop efficient vibration monitoring and structural health monitoring (SHM) methods for a horizontal-axis rotating wind turbine blade using a novel image-based tracking continuous scanning laser Doppler vibrometer (CSLDV) and new signal processing methods associated with tracking continuous scanning laser vibrometry. The image-based tracking CSLDV consists of a camera, a scanner with a set of orthogonal mirrors, and a single-point laser head. Currently, there are no suitable non-contact in-situ vibration monitoring and SHM methods for rotating wind turbine blades, and vibration monitoring and SHM of wind turbine blades are mainly accomplished by visual inspection of stationary blades or by using a limited number of embedded sensors. The image-based tracking CSLDV is capable of rapidly obtaining spatially dense vibration shapes (VSs), such as mode shapes and operating deflection shapes (ODSs) of a rotating structure under random excitation, by continuously sweeping its laser spot over the structure surface. VSs measured by the image-based tracking CSLDV can have more measurement points than those by a commercial scanning laser Doppler vibrometer in a point-by-point manner, and the former needs much less measurement time. Different image processing methods are developed for the image-based tracking CSLDV to extract the rotating structure from its background in captured images of the camera. Estimated real-time positions of the rotating structure can be used for estimating its rotation speed. Once the position of the rotating structure is determined in captured images, a scan path can be generated on it and rotation angles of mirrors of the scanner can be controlled so that the laser spot of the image-based tracking CSLDV can be swept along the path. New operational modal analysis methods are developed based on rigorous rotating beam and plate theories, which can estimate modal parameters, such as damped natural frequencies, modal damping ratios, undamped mode shapes, and ODSs, of the rotating structure under random excitation. A novel demodulation method with a reference signal is developed to identify positions of damages in a beam without its base-line information. Prototypes of an image-based short-range tracking CSLDV and an image-based long-range tracking CSLDV are developed for experimental validation of the proposed methods. Rotation speeds and modal parameters of rotating blades with different speeds that are excited by air flow that is considered as random excitation are estimated. Both undamped mode shapes of rotating blades on a straight scan path and their full-field undamped mode shapes are estimated and compared with each other. The proposed methods can address major challenges to monitor the vibration of a rotating horizontal-axis wind turbine blade and detect its potential damage in operational conditions.
High Performance Flexible and Scalable Thermoelectric Device and its Application as a Self-Sufficient Power Supply for Wearable Electronic Devices
(2024-01-01) Huang, Jiyuan; Madan, Deepa; Mechanical Engineering; Engineering, Mechanical
The rise of wearable electronics has emphasized the need for alternative power sources, as traditional batteries have limitations in terms of portability and cost. One promising solution is thermoelectric power generation, which can harvest waste heat or body heat to power these devices using thermoelectric (TE) materials. To address the global demand for low-cost, flexible thermoelectric generators (TEGs), this work describes a novel, energy-efficient TEG fabrication method of controlling the composite microstructure using 4 synergetic factors. The combination of (1) a small amount of chitosan binder (0.05 wt%), (2) heterogeneous (mixed nanoscale and microscale) TE particles, (3) applied mechanical pressure of 20 MPa combined with curing at a low temperature of 120°C for 30 mins and (4) thickness variation (170, 240, 300 ?m), results in an enhanced TE property of TEGs. The combination of these four factors controls the micro and nanostructure of the films to decouple their electrical and thermal conductivity effectively by achieving a improved electrical conductivity and a reduced thermal conductivity. This resulted in figures of merit (ZTs) of 0.89 and 0.5 for p-BST and n-BTS thinner (170 µm) films, respectively, comparable to other additive manufacturing methods despite eliminating the high-temperature, long-duration curing process. The process was also used to fabricate a 6-couple TEG device, which could generate 357.6 µW with a power density of 5.0 mW/cm2 at a ?T of 40 K. The device demonstrated air stability and flexibility for 1000 cycles of bending. Finally, the device was integrated with a voltage step-up converter to power an LED and charge and discharge capacitor at a ?T of 17 K, demonstrating its applicability as a self-sufficient power source. This work also further explored possibilities and approaches to integrate the TEGs to real world applications. Although the TE results are promising, there are still 2 factors to concern, (1) chalcogenides materials like p-BST and n-BTS are toxic and earth-rare, (2) The temperature difference will not be ideal as it in the research labs. Therefore, it is important to find new materials and methods to address these concerns. Tetrahedrites are promising thermoelectric materials in high-temperature applications because they are non-toxic and earth-abundant. MXene (Ti3C2) is a novel 2D material which has ultra-high electrical conductivity. Herein, this work demonstrates the fabrication of scalable and sustainable Cu12Sb4S13 (CAS) based composite films and flexible TEG devices (f-TEGs) with 2D MXene nanosheets using the previously developed energy efficient method for room temperature applications. 2D MXene nanosheets introduced energy-barrier scattering and nanoscale features to effectively increase the room-temperature ZT to 0.22, 10% higher than bulk CAS, by decoupling electrical conductivity, Seebeck coefficient, and thermal conductivity. CAS and 2D MXenes were found to be environmentally safe through a bacterial viability study. The process is used to create a 5-leg f-TEG device producing a power of 5.3 µW and a power density of 140 at a ?T of 25 K. Therefore, this work demonstrates that combining scalable and sustainable materials and methods is an effective strategy for high-performance room-temperature f-TEGs that could potentially harvest the low waste heat energy of the human body.
EVALUATING MICROCRACKS IN ENHANCING NANOFLUID FLOW FROM CAPILLARIES TO THE INTERSTITIAL SPACE IN TUMOR CORE REGIONS – THEORETICAL SIMULATIONS
(2024-01-01) Bireshetty, Veda Venkata Ramana; Zhu, Liang; Mechanical Engineering; Engineering, Mechanical
Limited drug delivery outcomes using systemic delivery are attributed to tumor microenvironment. The objective of this study is to investigate the effect of introduction of microcracks in tumors on tumoral IFP reduction to facilitate therapeutic agent delivery to tumors. We developed a theoretical model for fluid transport in a spherical tumor incorporating Starling’s law and Darcy’s law. Results have shown that introduction of 4 microcracks in tumors is effective to lower the maximal IFP in the tumor from 1941 Pa to 1722.1 Pa, by up to 11.3%. Although the reduction of the average IFP in the entire tumor is limited, it is evident that this approach is effective to decrease the average IFP in the tumor core regions with up to 16.8% reduction from the baseline case without microcrack. We conclude that introducing several microcracks in tumors is an effective method to facilitate transcapillary fluid/drug flow to tumor interstitial fluid space.
Custom multi-component force transducer design using topology optimization
(IOP, 2025-01-07) Kyun Sung, Myung; Lee, Soobum; Burns, Devin Edward; Persia, Jude Thaddeus
This paper proposes an innovative design framework for a multi-component force transducer subject to reversible load direction using topology optimization. Multi-component force transducers are used widely in industries ranging from robotics to healthcare. In this work, the proposed design framework is applied to a specific force transducer, a wind tunnel balance used within aeronautic ground testing. The axial component is one of the six components of the wind tunnel balance, and this component is difficult to design because the axial force is typically much smaller than other force components. This paper uses topology optimization to obtain a non-intuitive axial component design. To realize the design requirements, a new design formulation is suggested to amplify the gauge reading under a small axial loading and to suppress the gauge reading under nonaxial loadings. Prototypes are manufactured and their performances are experimentally verified. The proposed framework can be applied to any type of force transducer that needs to amplify a response from a certain force and to suppress the other responses.
Reversible symmetry breaking of BIC graphene plasmons for tunable mid-infrared absorption
(Optica, 2024-12-02) Guadagnini, Silvia; Ghanekar, Alok; Shrewsbury, Bo; Povinelli, Michelle L.
We use symmetry breaking to create switchable absorption peaks in mid-infrared (MIR) graphene metamaterials. We consider a structure consisting of graphene nanoribbons in contact with a gold grating. The unit cell of the untuned device is symmetric and supports both a bright and dark plasmon; the latter is also known as a BIC (bound state in the continuum) mode. We break symmetry by dynamically tuning the chemical potential of one of two graphene nanoribbons per unit cell. We show numerically that the BIC mode couples to the continuum, turning on an absorption peak. As the tuning increases, the two modes spatially flip and concentrate in a single nanoribbon. By controlling the relative chemical potential of two ribbons, we can control the wavelength of the switchable absorption peak.
RETHINKING DATA SCIENCE PEDAGOGY WITH EMBEDDED ETHICAL CONSIDERATIONS
(INTED, 2022-07) Janeja, Vandana; Sanchez, Maria
The focus of this paper is to present a tool to meet the need of developing ethical critical thinking in data science curricula for undergraduate students. New data science methods impact societies, communities directly or indirectly when dealing with open and other real-world datasets. In particular, for data science there is a need to develop ethical critical thinking while analyzing the data. In the knowledge discovery process there are many opportunities for ethical decision making that a data scientist can evaluate throughout the entire lifecycle of the data to do no harm. To address these concerns within a learning environment focused on skilled workforce development we first introduce a novel ethical data lifecycle framework and then propose a vehicle for implementation through a short term module that can be embedded into a fast paced data science course. The objective of the module is to increase the ethical thinking of students when analyzing data. Pre and post surveys were conducted across each of the two semesters to evaluate students’ attitudes towards ethical thinking. The analysis of the survey results suggests that the objective was achieved based on a positive shift toward agreement with statements related to the importance of ethical thinking.

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