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Eggplant Cultivar Demonstration Results For West-Central Indiana, 2025, Petrus Langenhoven, Alexandria Catherine Snabes Jan 2025

Eggplant Cultivar Demonstration Results For West-Central Indiana, 2025, Petrus Langenhoven, Alexandria Catherine Snabes

Midwest Vegetable Trial Reports

An eggplant cultivar demonstration at Purdue University's Meigs Horticulture Facility evaluated ten cultivars during the 2025 growing season to support evidence-based variety selection for Indiana growers. Eggplant production in Indiana totaled 34 acres in 2022, representing part of a national industry where 88.9% of 7,261 operations cultivate less than one acre. This demonstration provided performance data under Indiana conditions while offering hands-on learning for horticulture students. Results inform cultivar recommendations for small to medium-scale Midwest producers supplying diverse markets, including restaurants, farmers' markets, and ethnic food retailers seeking this Solanaceae crop for Asian, Mediterranean, and Middle Eastern cuisines.

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Scope And Mechanism Of The Ruthenium-Catalyzed Sp3 C–H Coupling Reaction Of 2-Alkylindoles With Enones For The Synthesis Of Carbazole Derivatives, Krishna Prasad Gnyawali, Mina Son, Donghun Hwang, Nuwan Asanka Pannilawithana, Mu-Hyun Baik, Chase S. Yi Jan 2025

Scope And Mechanism Of The Ruthenium-Catalyzed Sp3 C–H Coupling Reaction Of 2-Alkylindoles With Enones For The Synthesis Of Carbazole Derivatives, Krishna Prasad Gnyawali, Mina Son, Donghun Hwang, Nuwan Asanka Pannilawithana, Mu-Hyun Baik, Chase S. Yi

Chemistry Faculty Research and Publications

The catalytic system consisting of a cationic Ru–H complex 1 and 3,4,5,6-tetrachloro-1,2-benzoquinone (L1) was found to be highly effective for the dehydrative sp3 C–H coupling reaction of 2-alkyl substituted indoles with enones to form 2,4-disubstituted carbazole products. The analogous coupling reaction of 2-alkylindoles with linear enones bearing the cyclic olefinic group afforded tetracyclic carbazole products. A normal deuterium kinetic isotope effect was measured from the coupling reaction of 1,2-dimethylindole versus 1-methyl-2-(methyl-d3)indole with (E)-3-penten-2-one (kH/kD = 2.5). The Hammett plot was constructed from the reaction of para-substituted …

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Implementation Of Miniature Tensile Specimens In Mechanical Properties Assessment Of Directed Energy Deposited Ti-6al-4v: As-Built And Heat Treated, Saeid Alipour, Sung Heng Wu, Frank Liou, Arezoo Emdadi Jan 2025

Implementation Of Miniature Tensile Specimens In Mechanical Properties Assessment Of Directed Energy Deposited Ti-6al-4v: As-Built And Heat Treated, Saeid Alipour, Sung Heng Wu, Frank Liou, Arezoo Emdadi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Within the last two decades, additive manufacturing (AM), a. k.a. 3D printing, has provided promising solutions for producing near-net-shape components with intricate geometries. From the material perspective, titanium alloys, one of humankind's most essential structural materials, are being considered the first candidate for AMed parts due to their unique characteristics in strength-weight-corrosion combinations. However, measuring the mechanical properties of designed geometry remains a challenge due to the ineffectiveness of conventional standard tensile specimens in assessing the site-specific and intricate geometries. In AM, the current approach often consists of evaluating standard-sized samples with the assumption that components with complex geometries possess …

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In-Situ Thermographic Monitoring And Numerical Simulations Of Laser-Foil-Printing Additive Manufacturing, Tunay Turk, Tao Liu, Chia Hung Hung, Richard Billo, Jonghyun Park, Ming C. Leu Jan 2025

In-Situ Thermographic Monitoring And Numerical Simulations Of Laser-Foil-Printing Additive Manufacturing, Tunay Turk, Tao Liu, Chia Hung Hung, Richard Billo, Jonghyun Park, Ming C. Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser-foil-printing (LFP) is an additive manufacturing (AM) technique offering advantages over traditional powder-based methods. A deeper understanding of the melt pool dynamics is crucial for optimizing process parameters and achieving high-quality builds. This paper presents a combined approach utilizing numerical simulations and in-situ thermographic monitoring to investigate the relationship between scanning strategies, melt pool dimensions, and cooling rate in LFP. The numerical simulations are employed to predict melt pool behavior using a time-dependent thermal finite element analysis (FEA). Results demonstrate that the simulations accurately predict melt pool dimensions, showing strong agreement with experimental data. Simultaneously, real-time melt pool dynamics were …

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Assessing Porosity Limit In Freeze-Cast Sintered Lithium Titanate (Li₄Ti₅O₁₂) Materials, Rohan Parai, Dipankar Ghosh Jan 2025

Assessing Porosity Limit In Freeze-Cast Sintered Lithium Titanate (Li₄Ti₅O₁₂) Materials, Rohan Parai, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

This study aims to assess the lower limit of porosity that can be achieved in freeze-cast sintered lithium titanate (LTO) materials while maintaining the characteristic pore directionality. LTO materials were fabricated with solid loading varying in the range of 30–37 vol.%. Sucrose and cationic dispersant were used to vary viscosity and total solute concentration in the aqueous LTO suspensions. Two series of suspension compositions were selected for freeze-casting. In one series, aqueous suspensions were prepared by mixing deionized (DI) water, sucrose, and LTO powder, while in the other series, aqueous suspensions were prepared by mixing DI water, sucrose, cationic dispersant …

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Morphing Shape Metastructures Using The Hybrid Position Feedback Control And Bistable Structural Elements, Mehmet Simsek, Thomas E. Alberts, Onur Bilgen Jan 2025

Morphing Shape Metastructures Using The Hybrid Position Feedback Control And Bistable Structural Elements, Mehmet Simsek, Thomas E. Alberts, Onur Bilgen

Mechanical & Aerospace Engineering Faculty Publications

This research introduces a new multi-degree-of-freedom metastructure concept utilizing a hybrid position feedback controller. An arbitrary number of bistable segments, or structural elements, are connected serially or in parallel to form a distributed bistable structure, or a so-called metastructure. The hybrid controller, an unstable-then-stable second-order single-degree-of-freedom system, leverages the resonant mode of a bistable system to destabilize it and dynamically induce snap-through between equilibria. The metastructure inherits multiple bistable positions, maintaining equilibrium shapes without consuming power and enabling many equilibrium configurations. Two geometric configurations are proposed and analyzed using a modified hybrid feedback control approach, which rejects forces from neighboring …

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Side-By-Side Evaluation Of The Outgassing Rate And Ultimate Pressure Achieved Inside Tubes Made Of Low-Carbon And Stainless Steel, Aiman H. Al-Allaq, Md Abdullah Mamun, Matt Poelker, Abdelmageed Elmustafa Jan 2025

Side-By-Side Evaluation Of The Outgassing Rate And Ultimate Pressure Achieved Inside Tubes Made Of Low-Carbon And Stainless Steel, Aiman H. Al-Allaq, Md Abdullah Mamun, Matt Poelker, Abdelmageed Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

The hydrogen outgassing rate of a vacuum chamber made of AISI 1020 low-carbon steel was found to be notably smaller than a similar chamber made of AISI 316L stainless steel following heat treatment at 150 degrees C. When the chambers were baked at 400 degrees C, the outgassing rate of the 1020 low-carbon steel chamber was approximately 2000 times smaller than that of the 316L stainless-steel chamber. After quantifying hydrogen outgassing rates, vacuum chambers made of 1020 low-carbon steel and 316L stainless steel were heated for a prescribed duration and then pumped with an ion pump and nonevaporable getter pump …

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Polymorphism And Mechanical Behavior In Hot-Pressed 3d-Printed Polyamide Composite: Effects Of Pressure And Temperature, John Barber, Patricia Revolinsky, Jimesh Bhagatji, Diego Pedrazzoli, Sergii Kravchenko, Oleksandr Kravchenko Jan 2025

Polymorphism And Mechanical Behavior In Hot-Pressed 3d-Printed Polyamide Composite: Effects Of Pressure And Temperature, John Barber, Patricia Revolinsky, Jimesh Bhagatji, Diego Pedrazzoli, Sergii Kravchenko, Oleksandr Kravchenko

Mechanical & Aerospace Engineering Faculty Publications

The aim of this work is to study the effect of high-temperature compaction (HTC) upon the polymorphism and the mechanical behavior of an additively manufactured (AM) carbon fiber-reinforced polyamide (PA6). Different pressure and temperature levels during HTC were tested to determine the overall effect on the mechanical behavior and material crystalline composition. Treated, carbon fiber-reinforced PA6 samples were analyzed using differential scanning calorimetry, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and three-point bending testing. When considered with respect to as-printed samples, an HTC temperature of 190 °C combined with 80 psi pressure resulted in an increased flexural modulus and strength …

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Optimizing Material Selection And Operational Conditions For Xhv Systems: Lessons From Aisi 1020 And 316l Comparative Studies, Aiman H. Al-Allaq, Md Abdullah Mamun, Matt Poelker, Abdelmageed Elmustafa Jan 2025

Optimizing Material Selection And Operational Conditions For Xhv Systems: Lessons From Aisi 1020 And 316l Comparative Studies, Aiman H. Al-Allaq, Md Abdullah Mamun, Matt Poelker, Abdelmageed Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

In this study, AISI 1020 low-carbon steel was investigated as a cost-effective alternative to SS316L stainless steel for reaching extreme high vacuum (XHV) conditions. After being baked at 400°C, a vacuum chamber made of low-carbon steel material exhibited an outgassing rate approximately 2000 times smaller than a similar chamber made of stainless steel. Its activation energy for hydrogen diffusion (27 kJ/mol) is less than half that of stainless steel (60.3 kJ/mol), indicating more efficient hydrogen removal during bakeout. MolFlow+ simulations supported the experimental data and demonstrated the importance of system geometry optimization and minimizing stainless steel content for achieving optimal …

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Rheology Of Alumina Suspensions Subjected To Alternating Current Electric Fields For Freeze-Casting, Sivakumar Chithamallu, Ruksana Baby, Jacob L. Jones, Dipankar Ghosh Jan 2025

Rheology Of Alumina Suspensions Subjected To Alternating Current Electric Fields For Freeze-Casting, Sivakumar Chithamallu, Ruksana Baby, Jacob L. Jones, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

Alternating current (AC) electric field can extrinsically tune freeze‐cast microstructure, originating from field‐induced increase in viscosity of ceramic suspensions. However, the changes that occur in a ceramic suspension and rheological behavior, ultimately affecting freeze‐cast microstructure, are not well understood. Moreover, the effects of AC electrokinetic forces and temperature on viscosity need to be decoupled. The viscosity and temperature of ceramic suspensions subjected to AC field and direct heating were measured, revealing that the increase in viscosity is due to AC dielectrophoretic forces rather than field‐induced heating of suspension. The shear thinning behavior of suspensions characterized using a power‐law model reveals …

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Motion Artifacts Removal From Measured Arterial Pulse Signals At Rest: A Generalized Sdof-Model-Based Time-Frequency Method, Zhili Hao Jan 2025

Motion Artifacts Removal From Measured Arterial Pulse Signals At Rest: A Generalized Sdof-Model-Based Time-Frequency Method, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

Motion artifacts (MA) are a key factor affecting the accuracy of a measured arterial pulse signal at rest. This paper presents a generalized time–frequency method for MA removal that is built upon a single-degree-of-freedom (SDOF) model of MA, where MA is manifested as time-varying system parameters (TVSPs) of the SDOF system for the tissue–contact-sensor (TCS) stack between an artery and a sensor. This model distinguishes the effects of MA and respiration on the instant parameters of harmonics in a measured pulse signal. Accordingly, a generalized SDOF-model-based time–frequency (SDOF-TF) method is developed to obtain the instant parameters of each harmonic in …

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An Analytical Model Of Motion Artifacts In A Measured Arterial Pulse Signal—Part I: Accelerometers And Ppg Sensors, Md Mahfuzur Rahman, Subodh Toraskar, Mamun Hasan, Zhili Hao Jan 2025

An Analytical Model Of Motion Artifacts In A Measured Arterial Pulse Signal—Part I: Accelerometers And Ppg Sensors, Md Mahfuzur Rahman, Subodh Toraskar, Mamun Hasan, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

This paper, the first of two parts, presents an analytical model of motion artifacts (MAs) in measured pulse signals by accelerometers and photoplethysmography (PPG) sensors. As the transmission path from the true pulse signal in an artery to the sensor output (measured pulse signal), the tissue-contact-sensor (TCS) stack is modeled as a 1DOF (degree-of-freedom) system. MAs cause baseline drift of the mass and simultaneously time-varying system parameters (TVSPs) of the TCS stack. With arterial wall displacement and pulsatile pressure serving separately as the true pulse signal, an analytical model is developed to mathematically relate baseline drift and TVSP to a …

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Mitigating Out-Of-Plane Fiber Waviness In Afp Laminates With Tow-Gaps Via Selective Placement Of Thermoplastic Veils, Ahmadreza Ravangard, Kuthan Celebi, Sergii G. Kravchenko, Oleksandr G. Kravchenko Jan 2025

Mitigating Out-Of-Plane Fiber Waviness In Afp Laminates With Tow-Gaps Via Selective Placement Of Thermoplastic Veils, Ahmadreza Ravangard, Kuthan Celebi, Sergii G. Kravchenko, Oleksandr G. Kravchenko

Mechanical & Aerospace Engineering Faculty Publications

Fiber tow-gaps and overlaps formed during the Automated Fiber Placement (AFP) process pose a significant challenge by introducing non-uniform composite morphologies, often characterized by resin-rich regions and fiber waviness. These defects occur as deposited fibers sink into the gap regions during consolidation, with gap geometry determined during path planning. Such morphological inconsistencies can compromise structural reliability by initiating premature failure, particularly through localized out-of-plane waviness and resin accumulation. This study investigates the integration of high melting temperature thermoplastic veils, specifically polyetherimide (PEI), into fiber tow-gaps as a method to prevent ply sinking and reduce fiber waviness on both internal and …

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An Analytical Model Of Motion Artifacts In A Measured Arterial Pulse Signal—Part Ii: Tactile Sensors, Md Mahfuzur Rahman, Subodh Toraskar, Mamun Hasan, Zhili Hao Jan 2025

An Analytical Model Of Motion Artifacts In A Measured Arterial Pulse Signal—Part Ii: Tactile Sensors, Md Mahfuzur Rahman, Subodh Toraskar, Mamun Hasan, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

This paper, the second of two parts, presents an analytical model of motion artifacts (MA) in measured pulse signals by a tactile sensor, which contains a deformable microstructure sitting on a substrate. While the tissue-contact-sensor (TCS) stack and the sensor are both treated as a 1DOF (degree-of-freedom) system, tissue–sensor contact joins their mass together to form a 1DOF system with springs and dampers on both sides. MA on the sensor substrate causes baseline drift and time-varying system parameters (TVSP) of the TCS stack simultaneously. An analytical model is developed to mathematically relate baseline drift and TVSP to a measured pulse …

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A Comprehensive Review Of Piezoelectric Pvdf Polymer Fabrications And Characteristics, Nadia Ahbab, Sidra Naz, Tian-Bing Xu, Shihai Zhang Jan 2025

A Comprehensive Review Of Piezoelectric Pvdf Polymer Fabrications And Characteristics, Nadia Ahbab, Sidra Naz, Tian-Bing Xu, Shihai Zhang

Mechanical & Aerospace Engineering Faculty Publications

Polyvinylidene fluoride (PVDF) polymer films, renowned for their exceptional piezoelectric, pyroelectric, and ferroelectric properties, offer a versatile platform for the development of cutting-edge micro-scale functional devices, enabling innovative applications ranging from energy harvesting and sensing to medical diagnostics and actuation. This paper presents an in-depth review of the material properties, fabrication methodologies, and characterization of PVDF films. Initially, a comprehensive description of the physical, mechanical, chemical, thermal, electrical, and electromechanical properties is provided. The unique combination of piezoelectric, pyroelectric, and ferroelectric properties, coupled with its excellent chemical resistance and mechanical strength, makes PVDF a highly valuable material for a wide …

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Outgassing Measurements Of Bare And Magnetite-Coated Low-Carbon Steel Vacuum Chambers, Aiman H. Al-Allaq, Md Abdullah Mamun, Matt Poelker, Abdelmageed Elmustafa Jan 2025

Outgassing Measurements Of Bare And Magnetite-Coated Low-Carbon Steel Vacuum Chambers, Aiman H. Al-Allaq, Md Abdullah Mamun, Matt Poelker, Abdelmageed Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

The outgassing properties of bare and magnetite-coated AISI 1020 low-carbon steel vacuum chambers were evaluated to establish material selection criteria for extreme high vacuum applications, namely, to explore the possibility of using these materials to build next-generation spin-polarized photoelectron guns. Water outgassing measurements using the throughput method revealed that the magnetite-coated chamber exhibited five times lower outgassing at room temperature prior to baking, but this advantage disappears after 80 °C baking. Hydrogen outgassing measurements demonstrated significant differences after intensive heat treatment: the bare low-carbon steel vacuum chamber achieved a specific outgassing rate of 9.6 × 10−16 Torr L s …

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Artificial Intelligence In Educational Research And Scholarship: Seven Framings, Eamon Costello, Giselle Ferreira, Stefan Hrastinski, Jason K. Mcdonald, Ahmed Tlili, George Veletsianos, Victoria I. Marin, Henk Huijser, Sharon Altena Jan 2025

Artificial Intelligence In Educational Research And Scholarship: Seven Framings, Eamon Costello, Giselle Ferreira, Stefan Hrastinski, Jason K. Mcdonald, Ahmed Tlili, George Veletsianos, Victoria I. Marin, Henk Huijser, Sharon Altena

Faculty Publications

In a recent interview (Bender et al., 2025), Professor Emily M. Bender discussed the limitations of technical solutions in addressing harmful Artificial Intelligence (AI) bias. She described a particular point we may reach at which technical solutions stop working, and when we should then widen the lens to ask about the problem framing itself. This is a crucial step in any inquiry that is of concern to both novice and experienced researchers alike: moving from problem-solving to problematisation. This commentary aims to provide educational researchers with a glimpse into the wide array of research problems and problematisation of AI in …

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Anisotropic Third-Harmonic Vortex Beam Generation With Ultrathin Germanium Arsenide Fork Gratings, Jayanta Deka, Jie Gao, Xiaodong Yang Jan 2025

Anisotropic Third-Harmonic Vortex Beam Generation With Ultrathin Germanium Arsenide Fork Gratings, Jayanta Deka, Jie Gao, Xiaodong Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Optical vortices have the tremendous potential to increase data capacity by leveraging the extra degree of freedom of orbital angular momentum. On the other hand, anisotropic 2D materials are promising building blocks for future integrated polarization-sensitive photonic and optoelectronic devices. Here, highly anisotropic third-harmonic optical vortex beam generation is demonstrated with fork holograms patterned on ultrathin 2D germanium arsenide flakes. It is shown that the anisotropic nonlinear vortex beam generation can be achieved independent of the fork grating orientation with respect to the crystallographic orientation. Furthermore, 2D fork hologram is designed to generate multiple optical vortices having different topological charges …

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Thermo-Rheological And Tribological Properties Of Low- And High-Oleic Vegetable Oils As Sustainable Bio-Based Lubricants, Abiodun Saka, Tobechukwu K. Abor, Anthony C. Okafor, Monday U. Okoronkwo Jan 2025

Thermo-Rheological And Tribological Properties Of Low- And High-Oleic Vegetable Oils As Sustainable Bio-Based Lubricants, Abiodun Saka, Tobechukwu K. Abor, Anthony C. Okafor, Monday U. Okoronkwo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Vegetable oil-based lubricants have attracted increased research attention in recent decades as sustainable alternatives to conventional petroleum-based lubricants in metal machining. However, more studies are required to fully elucidate the thermo-rheological and tribological properties. This study presents an investigation of the thermo-rheological and tribological properties of different vegetable oils, including low- and high-oleic soybean oil, high-oleic sunflower, safflower, and canola oils. The lubricity, and evolution of viscosity and thermodynamic properties as a function of temperature were investigated to obtain important parameters including the viscosity index, flow behavior index, flow activation energy, specific heat capacity, thermal conductivity, coefficient of friction, contact …

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A Ground Thermal Vacuum Facility For Simulating Cryogenic Space Environment Conditions, Emmanuel Kofi Asuako Wie-Addo, Lucas Scott, Daoru Han Jan 2025

A Ground Thermal Vacuum Facility For Simulating Cryogenic Space Environment Conditions, Emmanuel Kofi Asuako Wie-Addo, Lucas Scott, Daoru Han

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work presents the ongoing progress of a vacuum facility upgrade at the Gas and Plasma Dynamics Laboratory (GPDL) at Missouri University of Science and Technology. A movable shroud has been fabricated and installed to enable the simulation of extreme cold conditions. The cooling rate of the shroud, a dummy test article, and a platform, using liquid nitrogen as the thermal fluid, is analyzed and reported under varying vacuum conditions for cryogenic runs. Preliminary testing revealed substantial thermal exchange between the shroud and the chamber walls, underscoring the necessity for implementing effective thermal isolation measures to mitigate heat transfer.

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Improving Neural Network Efficiency With Multi-Fidelity And Dimensionality Reduction Techniques, Vignesh Sella, Thomas O'Leary-Roseberry, Xiaosong Du, Mengwu Guo, Joaquim R.R.A. Martins, Omar Ghattas, Karen Willcox, Anirban Chaudhuri Jan 2025

Improving Neural Network Efficiency With Multi-Fidelity And Dimensionality Reduction Techniques, Vignesh Sella, Thomas O'Leary-Roseberry, Xiaosong Du, Mengwu Guo, Joaquim R.R.A. Martins, Omar Ghattas, Karen Willcox, Anirban Chaudhuri

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Design problems in aerospace engineering often require numerous evaluations of expensive to-evaluate high-fidelity models, resulting in prohibitive computational costs. One way to address the computational cost is through building surrogates, such as deep neural networks (DNNs). However, DNNs may only be an effective surrogate when sufficient evaluations of the high-fidelity model are required such that the up-front training cost is amortized, or in situations that require real-time responses (such as interactive visualizations). Typically, the data requirements for adequately accurate training of DNNs are often impractical for engineering applications. To alleviate this issue, the proposed work utilizes output dimensionality reduction along …

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Tensile Behavior Of Directed Energy Deposited Bi-Metallic Ti-Ni-Based Alloy At Interfacial Area, Yitao Chen, Cesar Ortiz Rios, Frank Liou Jan 2025

Tensile Behavior Of Directed Energy Deposited Bi-Metallic Ti-Ni-Based Alloy At Interfacial Area, Yitao Chen, Cesar Ortiz Rios, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Ti-Ni-based bi-metallic shape memory alloy was fabricated using directed energy deposition, and the tensile testing behavior at two sections after post-heat treatments were focused. The Ti-rich Ti-Ni-Cu ternary shape memory alloy was first fabricated on a TiNi shape memory alloy with near-equiatomic composition to achieve multi-functional shape memory behaviors using powder-based additive manufacturing. The bi-metallic part then underwent 400°C and 600°C heat treatment at the interfacial area, and the interfacial area was subject to tensile loading and unloading. The digital image correlation technique was applied to extract the tensile stress–strain behavior and map out the local strain evolution of …

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Advancing Cislunar Space Domain Awareness Through Robust Optimization Framework For Optical Sensors-Based Autonomous Satellite Systems, Smriti Nandan Paul, Siwei Fan, Igor Panfil Jan 2025

Advancing Cislunar Space Domain Awareness Through Robust Optimization Framework For Optical Sensors-Based Autonomous Satellite Systems, Smriti Nandan Paul, Siwei Fan, Igor Panfil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The number of cislunar resident space objects is expected to proliferate rapidly because of strategic interests targeting long-term presence on the Moon and exploration of other planets (e.g., Artemis Accords) and liberalization of space through the entry of private space players (e.g., Intuitive Machines). It necessitates expanding current near-Earth space domain awareness (SDA) operation systems and knowledge to the relatively unexplored cislunar region. Besides the traditional complexities, xGEO orbits (orbits beyond the geosynchronous Earth orbit (GEO) region) face additional challenges because of highly non-linear and non-Keplerian dynamics, which results in inaccuracies in uncertainty propagation and state estimation. Further challenges include …

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Characterizing Intralaminar Distal Crack And Delamination In Multidirectional Laminates Under Low Velocity Impact: Modeling Approach With Ultrasound Testing Validation, Niildiip Chandraa, Rachel Van Lear, Arief Yudhanto, Yuqing Zhao, David A. Jack, Douglas E. Smith Jan 2025

Characterizing Intralaminar Distal Crack And Delamination In Multidirectional Laminates Under Low Velocity Impact: Modeling Approach With Ultrasound Testing Validation, Niildiip Chandraa, Rachel Van Lear, Arief Yudhanto, Yuqing Zhao, David A. Jack, Douglas E. Smith

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multidirectional laminated composites are essential for load-bearing structures, especially under frequent impact loading. While existing modeling techniques simulate various impact damage modes, our understanding of the underlying mechanisms, specifically the initiation and progression of intralaminar distal cracks and interlaminar delamination, needs improvement. Validating these mechanisms is crucial for enhancing modeling accuracy and expediting the design process. In this work, we propose a three-dimensional finite element modeling (3D FEM) approach aimed at elucidating the impact damage mechanisms in multidirectional carbon fiber reinforced polymer (CFRP). Our model incorporates cohesive zone models (CZM) to simulate the behavior of intralaminar cracks at distal points …

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Maternal Lipidomics For The Accurate Prediction Of Fetal Cyanotic Congenital Heart Defects, Onur Turkoglu, Nadia Ashrafi, Ali Yilmaz, Romana Ashrafi Mimi, Abdullah Khan, Perry Friedman, Ciara Talbot, Stewart Graham, Ray Bahado-Singh Jan 2025

Maternal Lipidomics For The Accurate Prediction Of Fetal Cyanotic Congenital Heart Defects, Onur Turkoglu, Nadia Ashrafi, Ali Yilmaz, Romana Ashrafi Mimi, Abdullah Khan, Perry Friedman, Ciara Talbot, Stewart Graham, Ray Bahado-Singh

Conference Presentation Abstracts

Objective: Late diagnosis of cyanotic congenital heart defects (CCHD) significantly increases newborn morbidity and mortality. However, a significant percentage of CCHD cases remain undetected prenatally. Our objectives were therefore to evaluate the accuracy of maternal serum lipidomic markers for the prenatal detection of CCHD and also to elucidate the pathogenesis of these disorders. Study Design: This prospective case-control study included 40 cases of CHD (22 cyanotic, 18 acyanotic) and 39 unaffected controls. Maternal serum samples were profiled via a combination of Ultra-High-Performance Liquid Chromatography coupled with Mass Spectrometry and Nuclear Magnetic Resonance. The mean of each lipid specie was compared …

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Anisotropic And Temperature-Tunable Second-Harmonic Vortex Generation In Ferroelectric Nbocl2 Holograms, Jayanta Deka, Xiaodong Yang, Jie Gao Jan 2025

Anisotropic And Temperature-Tunable Second-Harmonic Vortex Generation In Ferroelectric Nbocl2 Holograms, Jayanta Deka, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Optical vortex beams with helical phase fronts have immense potential to enhance data capacity due to the unbounded values of orbital angular momentum. Chip-scale platforms for producing vortex beams are of paramount importance for a variety of applications. On the other hand, 2D materials with unique optical properties are essential for developing multifunctional ultrathin photonic devices. Here, anisotropic and temperature-tunable second-harmonic vortex beam generation is demonstrated with ultrathin ferroelectric niobium oxide dichloride (NbOCl2) fork holograms. The polarization-resolved Raman measurements are performed on the NbOCl2 crystal to understand the anisotropic behavior of the Raman modes. It is demonstrated …

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Deep Reinforcement Learning-Based Optimal Takeoff Trajectory Design Of An Evtol Drone, Nathan M. Roberts, Bingling Huang, Xiaosong Du Jan 2025

Deep Reinforcement Learning-Based Optimal Takeoff Trajectory Design Of An Evtol Drone, Nathan M. Roberts, Bingling Huang, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The continuing development of electric vertical take-off and landing (eVTOL) aircraft presents promising opportunities to alleviate transportation congestion. However, designing and executing takeoff trajectories that optimally balance energy usage, passenger comfort, and aircraft constraints remains challenging. Conventional design optimization provides a solution for pre-defined flight conditions and environments but is not ideal in real-world applications. In contrast, deep reinforcement learning (DRL) implements optimal policy making real-time decisions with no assumption of mathematical models. Seeing the lack of literature on DRL-based takeoff trajectory design of eVTOL aircraft, we implement and conduct DRL-based optimal takeoff trajectory designs for the Airbus3 Vahana …

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Comparing The Sensitivity And Specificity Of Novel Motor Assessments For Traumatic Brain Injury, Paula K. Johnson, Ariana M. Hedges-Muncy, Erin D. Bigler, Lorie Richards, Steven Knight Charles Jan 2025

Comparing The Sensitivity And Specificity Of Novel Motor Assessments For Traumatic Brain Injury, Paula K. Johnson, Ariana M. Hedges-Muncy, Erin D. Bigler, Lorie Richards, Steven Knight Charles

Faculty Publications

Background: Portable technology that records movements with high accuracy provides potential for sensitive clinical movement tests for individuals who experienced a traumatic brain injury (TBI). Objective: (1)To present impairments assessed using markerless motion capture (MMC) and (2) to compare the sensitivity and specificity of the MMCmediated tests to each other and to common clinical tests. Design: Screening study, using as criterion standard the ability to classify participant with TBI versus control participant. Setting: Research laboratory. Participants: The study included 30 individuals with TBI and 101 control participants. Entry criteria included most recent head injury < 5 years old, no history of movement issues prior to injury, no movement-affecting medications, and sufficient cognitive ability to follow instructions. Interventions: Not applicable. Main Outcome Measures: Performance on MMC-mediated tests and existing clinical analogs. MMC-mediated tests included finger oscillation, simple reaction time, and visually guided movement tasks. For comparison, participants also completed the following clinical tests: Halstead–Reitan finger tapping, simple reaction time test, and Beery Visuomotor Integration test. Impairments were identified as test scores of participants with TBI that fell outside of the 95% interval of control participants’ test scores. Random forest analysis was used to calculate the sensitivity and specificity of MMC and clinical tests according to their ability to correctly classify participants with TBI and control participants. Results: MMC-mediated tests revealed impairments in more participants with TBI than clinical tests in all three TBI groups (mild, repeated, and moderate to severe). Similarly, MMC-mediated tests revealed a higher percentage of scores as impairments than clinical tests in all three groups with TBI. Furthermore, MMC-mediated tests proved more sensitive and more specific than clinical tests (70% versus 50% and 98% versus 93%, respectively). Conclusion: MMC-mediated tests are sensitive and specific (compared to traditional clinical tests) and have potential to fill a gap in clinical care of TBI.

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Eco-Friendly Synthesis And Stability Analysis Of Cspbbr3 And Poly(Methyl Methacrylate)-Cspbbr3 Films, You-Lin Huang, Wei Li, Fuqian Yang Jan 2025

Eco-Friendly Synthesis And Stability Analysis Of Cspbbr3 And Poly(Methyl Methacrylate)-Cspbbr3 Films, You-Lin Huang, Wei Li, Fuqian Yang

Mechanical Engineering Faculty Publications

This study presents an eco-friendly mechanochemical synthesis of cesium lead bromide (CsPbBr3), eliminating the need of organic solvents and high temperatures. The synthesized CsPbBr3 powder is used to fabricate poly(methyl methacrylate) (PMMA)-CsPbBr3 films and CsPbBr3 nanocrystals (NCs). The photoluminescence (PL) peaks of the emission light are centered at 541 nm, 538 nm, and 514 nm for the CsPbBr3 powder, PMMA-CsPbBr3 films, and CsPbBr3 NCs, respectively, correlating with crystal sizes of 0.96, 0.56, and 0.12 μm, respectively. The PL lifetime analysis reveals decay times () of (4.18, 20.08), (5.7, 46.99), and (5.81, …

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Table Of Contents, Jtaa Editors Jan 2025

Table Of Contents, Jtaa Editors

Suffolk Journal of Trial and Appellate Advocacy

No abstract provided.

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