Engineering Commons^™

Enhancing Frequency Event Detection In Power Systems Using Two Optimization Methods With Variable Weighted Metrics, Hussain A. Alghamdi, Midrar A. Adham, Umar Farooq, Robert B. Bass

Electrical and Computer Engineering Faculty Publications and Presentations

This research presents a novel technique that refines the performance of a frequency event detection algorithm with four adjustable parameters based on signal processing and statistical methods. The algorithm parameters were optimized using two well-established optimization techniques: Grey Wolf Optimization and Particle Swarm Optimization. Unlike conventional approaches that apply equally weighted metrics within the objective function, this work implements variable weighted metrics that prioritize specificity, thereby strengthening detection accuracy by minimizing false-positive events. Realistic small- and large-scale frequency datasets were processed and analyzed, incorporating various events, quasi-events, and non-events obtained from a phasor measurement unit in the Western Interconnection. An …

Effects Of Wetting Events On Mass Timber Surface Microbial Communities And Voc Emissions: Implications For Building Operation And Occupant Well-Being, Gwynne Á. Mhuireach, Susan Collins, Leslie Dietz, Patrick Finn Horve, Aurélie Laguerre, Dale Northcutt, Jason Stenson, Kevin Van Den Wymelenberg, Elliott Gall, Mark Fretz

Mechanical and Materials Engineering Faculty Publications and Presentations

IntroductionHumans have used wood as a construction material throughout history. Currently, mass timber products, such as cross-laminated timber (CLT), are becoming more popular as a structural material, since they are renewable and have a lower carbon footprint than concrete or steel. Nonetheless, some building types, such as healthcare, veterinary, and food manufacturing, avoid using structural mass timber due to concerns about microbial growth in the event of wetting. One solution is to use protective coatings on mass timber products to increase moisture resistance, although the coatings themselves may generate concerns about volatile organic compound (VOC) emissions. Natural uncoated wood also …

An Effective Genetic Algorithm For Mixed Precision, Wanyu Zhang, Yu Shang, Min Tsao, Yiwei Li, Xiaoyu Song

Electrical and Computer Engineering Faculty Publications and Presentations

The precision of floating-point numbers is a critical task in high-performance computing. Many scientific applications rely on floating-point arithmetic, but excessive precision can lead to unnecessary computational overhead. Reducing precision may introduce unacceptable errors. Addressing this trade-off is essential for optimizing performance while ensuring numerical accuracy. In this paper, we present a genetic algorithm-based approach for tuning the precision of floating-point computations. Our method leverages algorithmic differentiation and first-order Taylor series approximation to assess the impact of precision variations efficiently. We employ stochastic partitioning algorithms with multiple precision combinations that meet the error requirements. Moreover, we present a genetic heuristic …

Accelerating High-Throughput Phonon Calculations Via Machine Learning Universal Potentials, Huiju Lee, Vinay I. Hegde, Chris Wolverton, Yi Xia

Mechanical and Materials Engineering Faculty Publications and Presentations

Phonons play a critical role in determining various material properties, but conventional methods for phonon calculations are computationally intensive, limiting their broad applicability. In this study, we present an approach to accelerate high-throughput harmonic phonon calculations using machine learning universal potentials (MLIPs) combined with an efficient training dataset generation strategy. Instead of computing phonon properties from a large number of supercells with small atomic displacements of a single atom, our approach uses a smaller subset of supercell structures where all atoms are randomly displaced by 0.01 to 0.05 UŮ, significantly reducing computational costs. We train a state-of-the-art MLIP based on …

Seabed Characterization Using Ambient Sound For A Range-Dependent Track In The New England Mud Patcha, Martin Siderius, Stan E. Dosso, Brian Granger

Electrical and Computer Engineering Faculty Publications and Presentations

Wind-generated, ocean ambient sound data were used to characterize seabed properties along a track in the New England Mud Patch. A 15-m vertical array, consisting of 16 hydrophones, collected ambient sound data across the 50–5000 Hz frequency band. The array drifted for 1 h, covering a 1.7 km track. Seabed characterization was performed using beamforming techniques, which limited the analysis to the 400–700 Hz band. Passive fathometer processing was applied to estimate the water–seabed interface and sub-bottom layering. Additionally, the data were used to estimate the power reflection coefficient, which was then used as input for a trans-dimensional geoacoustic inversion. …

Vessel Trajectory Prediction With Recurrent Neural Networks: An Evaluation Of Datasets, Features, And Architectures, Isaac Slaughter, Jagir Laxmichand Charla, Martin Siderius, John Lipor

Electrical and Computer Engineering Faculty Publications and Presentations

Maritime situational awareness tasks such as port management, collision avoidance, and search-and-rescue missions rely on accurate knowledge of vessel locations. The availability of historical vessel trajectory data through the Automatic Identification System (AIS) has enabled the development of prediction methods, with a recent focus on trajectory prediction via recurrent neural networks (RNNs) and other deep learning architectures. While these methods have shown promising performance benefits over kinematic and clustering-based models, comparing among RNN-based models remains difficult due to variations in evaluation datasets, region sizes, vessel types, and numerous other design choices. As a result, it is not clear whether recent …

Geotechnical Centrifuge Test Of A Pile-Supported Wharf In Silt (Test Aep01), Andrew Earl Parrott

Dissertations and Theses

There have been many documented cases in the U.S. and elsewhere of failure to ports, wharves, and bridges during seismic events due to liquefaction of soils adjacent to foundations. The major design guidelines for surface and maritime transportation structures, such as those offered in ASCE 61-14, Port of Anchorage Seismic Design Manual (POA 2017), AASHTO (2020), Caltrans (2012), and many others, differ considerably on the recommendations for combining the expected inertial and kinematic loads on the pile system. This knowledge gap becomes wider for pile foundations embedded in low plasticity silt, as varying opinions exist on the appropriate characterization of …

Confirmation Of The Scanpyramids North Face Corridor In The Great Pyramid Of Giza Using Multi-Modal Image Fusion From Three Non-Destructive Testing Techniques, Thomas Schumacher, Polina Pugacheva, Hussien Allam, Alejandro Ramirez-Pinero, Benedikt Maier, Johannes Rupfle, Khalid Helal, Olga Popovych, Amr G. Hamza, Mohamed Sholqamy, Multiple Additional Authors

Civil and Environmental Engineering Faculty Publications and Presentations

Abstract While non-destructive testing (NDT) measurements have been reported individually for archeological surveys of cultural heritage structures, only a few studies to date have attempted to combine NDT images by means of image fusion (IF). In this article, novel multimodal IF results from three different NDT techniques collected at the Chevron located on the Great Pyramid of Giza (aka. as Khufu’s Pyramid) are presented. The Chevron is an assembly of limestone blocks located in front of the recently confirmed ScanPyramids North Face Corridor (SP-NFC), which had been previously hidden for 4500 years. Under the research activities of the ScanPyramids mission, …

Gait Characteristics In People With Friedreich Ataxia: Daily Life Versus Clinic Measures, Hannah L. Casey, Vrutangkumar V. Shah, Daniel Muzyka, James Mcnames, Mahmoud El-Gohary, Kristen Sowalsky, Delaram Safarpour, Patricia Carlson-Kuhta, Christian Rummey, Fay B. Horak, Christopher M. Gomez

Electrical and Computer Engineering Faculty Publications and Presentations

Gait assessments in a clinical setting may not accurately reflect mobility in everyday life. To better understand gait during daily life, we compared measures that discriminated Friedreich ataxia (FRDA) from healthy control (HC) subjects in prescribed clinic tests and free, daily-life monitoring.MethodsWe recruited 9 people with FRDA (median age: 20, IQR [12, 48] years). A comparative healthy control (HC) subject cohort of 9 was sampled using propensity matching on age (median age: 18 [13, 22] years). Subjects wore 3 inertial sensors (one each foot and lower back) in the laboratory during a 2-min walk at a natural pace, followed by …

Exploring The Effect Of The Architecture Morphology On Urban Ventilation At Block Scale Using Cfd-Gis And Random Forest Combined Method, Bin Guo, Miaoyi Chen, Xiaowei Zhu, Zheng Wang, Lu Li, Lin Pei, Hailong Chen, Puhao Chen, Tengyue Guo

Mechanical and Materials Engineering Faculty Publications and Presentations

Urban ventilation plays a crucial role in dispersing air pollutants and mitigating the urban heat island effect. As a key factor, urban architectural morphology can significantly impact the wind field and ventilation efficiency. This study combines Computational Fluid Dynamics (CFD), Geographic Information System (GIS), and Random Forest (RF) methods to investigate the influence of architectural morphology on urban ventilation at the block scale. First, Remote Sensing (RS) and GIS were used to extract architectural morphology parameters. Second, CFD simulations, guided by in-situ observations, were conducted to model the wind field, with the Standard k-ɛ model validated as the optimal choice. …

Realizing Intrinsically Ultralow And Glass-Like Thermal Transport Via Chemical Bonding Engineering, Zhonghao Xia, Xingchen Shen, Jun Zhou, Yuling Huang, Yali Yang, Jiangang He, Yi Xia

Mechanical and Materials Engineering Faculty Publications and Presentations

Crystals exhibiting glass-like and low lattice thermal conductivity ( ) are not only scientifically intriguing but also practically valuable in various applications, including thermal barrier coatings, thermoelectric energy conversion, and thermal management. However, such unusual are typically observed only in compounds containing heavy elements, with large unit cells, or at high temperatures. In this study, chemical bonding principles are utilized to weaken the Ag–Ag bonds and enhance lattice anharmonicity. The incorporation of a chalcogen anion as a bridge ligand is proposed to facilitate phonon rattling in Ag6-octahedron-based compounds. Guided by this design strategy, five Ag6 octahedron-based compounds, AAg3X2 (A = …

Combining Passive And Active Ultrasonic Stress Wave Monitoring For The Characterization Of The Early-Age Properties Of A Uhpfrc Beam, Numa Bertola, Thomas Schumacher, Ernst Niederleithinger, Eugen Bruhwiler

Civil and Environmental Engineering Faculty Publications and Presentations

This article focuses on the characterization of the early-age properties of Ultra-High-Performance Fiber-Reinforced Cementitious Composite (UHPFRC), which is becoming popular for designing lightweight and durable structures. Due to the large proportion of cement in the mix, the hardening of UHPFRC is significantly faster than conventional concrete. Therefore, the development of UHPFRC properties, such as the elastic modulus, is difficult to monitor as it happens while elements are within the formwork. For this reason, the hydration process of UHPFRC elements is not fully understood yet. A combined passive (or acoustic emission) and active ultrasonic stress wave monitoring approach has the potential …

Layout-Aware Quantum Circuitry And Algorithmic Extensions To Grover's Algorithm, Ali Al-Bayaty

Dissertations and Theses

Lov K. Grover introduced, in 1996, Grover's algorithm as a quantum search algorithm to find all solutions for quantum oracles representing classical problems. My research observed that the Grover diffusion operator of Grover's algorithm gives wrong solutions when Boolean oracles are designed in some logical structures. Therefore, I invented the new "controlled-diffusion operator" for Boolean oracles as a new approach for Grover's algorithm that always correctly solves the problem of Grover's algorithm.

Another important problem in quantum computing is designing reliable and cost-effective quantum gates using reversible binary logic. In classical logic design, the stage of logic design can be …

Advances In Theory And Computational Methods For Next-Generation Thermoelectric Materials, Junsoo Park, Alex M. Ganose, Yi Xia

Mechanical and Materials Engineering Faculty Publications and Presentations

This is a review of theoretical and methodological development over the past decade pertaining to computational characterization of thermoelectric materials from first principles. Primary focus is on electronic and thermal transport in solids. Particular attention is given to the relationships between the various methods in terms of the theoretical hierarchy as well as the tradeoff of physical accuracy and computational efficiency of each. Further covered are up-and-coming methods for modeling defect formation and dopability, keys to realizing a material's thermoelectric potential. We present and discuss all these methods in close connection with parallel developments in high-throughput infrastructure and code implementation …

Life Safety In The Reliability-Based Design And Assessment Of Structures, Mahesh Pandey, Celeste Viljoen, Andrew Way, Katharina Fischer, Miroslav Sykora, Dimitris Diamantidis, Raphael D. J. M. Steenbergen, Niels Lind, Dan M. Frangopol, David Y. Yang, Multiple Additional Authors

Civil and Environmental Engineering Faculty Publications and Presentations

We review the developments in life safety and the incorporation thereof in the design and assessment of structures over the last 50 years. Various measures of life safety are presented that have been developed according to the marginal life saving cost principle based on individual, societal and economic considerations. Target probabilities of failure, or target reliabilities, are central to modern structural design and assessment. These are derived either through back-calibration to existing practice or through life cycle cost minimisation, both of which yield comparable safety levels, and are underpinned by lower bounds from life safety. Life cycle cost minimisation is …

Scshm Benchmark Study On Bridge In-Service Structural Monitoring, Maria Pina Limongelli, Doug Thomson, Screenevas Alampalli, Aftab Mufti, Thomas Schumacher, Luca Martinelli, Othmane Lasri, Harry Shenton, Genda Chen, Mohammad Noori, Multiple Additional Authors

Civil and Environmental Engineering Faculty Publications and Presentations

The mission of the Society of Civil Structural Health Monitoring (SCSHM, previously known as ISHMII) is to advance the understanding and application of structural monitoring methodologies for the management of civil infrastructure systems. To enable comparative and contrasting studies of various monitoring issues and technologies, the SCSHM Committee on Data-Enhanced Infrastructures Management (DEIMC) identified the need for benchmark problems in the areas of bridge and building structural monitoring. This article reports and briefly discusses the first benchmark study on in-service structural monitoring of bridges that was developed in collaboration with the University of Manitoba, and presents the structure details, study …

Impact Of Roughness Spanwise Wavelength On Secondary Flow Rearrangement, Jianzhi Yang, Xiang I. A. Yang, Luoqin Liu, Jian Zhu, Xiaowei Zhu

Mechanical and Materials Engineering Faculty Publications and Presentations

Spanwise heterogeneity in surface roughness generates secondary mean flows in a rough-wall turbulent boundary layer. This study investigates the influence of roughness spanwise wavelength on the arrangement of these secondary flows using direct numerical simulation (DNS). We systematically vary the spanwise wavelength, δS/δ⁠, from ππ/16 to π2π⁠, while maintaining constant roughness height and surface coverage density. Here, S represents the roughness spanwise wavelength, and δδ denotes the outer length scale, which in this case is the half-channel height. Secondary flows are observed in all DNS cases, but their configurations depend on the spanwise wavelength. Specifically, small wavelengths result in low-momentum …

Quantum Finite Automaton Using Ternary Rotation Quantum Gates And Chrestenson Family Quantum Gates, Yuchen Huang, Marek Perkowski, Xiaoyu Song, John M. Acken

Electrical and Computer Engineering Faculty Publications and Presentations

Quantum automata can solve certain problems with a smaller state space than classical automata. We developed a quantum finite automaton using ternary rotation quantum gates and the Chrestenson family of ternary quantum gates. The main idea of this paper is to show how to combine rotation ternary quantum circuit-based QuantumFinite Automaton and quantum reversible circuit-based Deterministic Finite Automaton to build a more powerful machine. The combined machine can enable more complex language and pattern recognition. The developed quantum finite automaton and resulting combined machine can be used for robotics applications such as language, gesture, and motion recognition.

Integrating The Interconnections Between Groundwater And Land Surface Processes Through The Coupled Nasa Land Information System And Parflow Environment, Fadji Z. Maina, Dan Rosen, Peyman Abbaszadeh, Chen Yang, Sujay V. Kumar, Matthew Rodell, Reed Maxwell

Civil and Environmental Engineering Faculty Publications and Presentations

Understanding the interactions between the atmosphere, the land, and the subsurface is fundamental to hydrology and is critical for a better assessment of the impacts of climate change and human management on hydrological systems. However, many land surface models simplify the subsurface hydrology and thereby these interactions. In this study, we couple the land surface model Noah‐MP included in the NASA Land Information System (LIS) with the integrated hydrologic model ParFlow (ParFlow‐LIS) using the Earth System Modeling Framework (ESMF) and the National United Operational Prediction Capability (NUOPC). This coupling improves the simulation of water and energy cycle processes by adding …

How Was Your Crossing Experience? Development Of A Pedestrian Satisfaction With Unsignalized Crossings Scale, Seth Lajeunesse, Wesley Kumfer, Sirisha Kothuri, Krista Nordback, Nathan Mcneil

Civil and Environmental Engineering Faculty Publications and Presentations

Unsignalized pedestrian crossing accommodations can improve pedestrian safety, yet their quality of service for pedestrians remains understudied. The present study explored whether and how pedestrians’ satisfaction with crossing unsignalized crossings varied according to the type of crossing accommodation used, that is, the rectangular rapid-flashing beacon (RRFB) with median island, median island alone, marked crosswalk, and unmarked crosswalk. The research team collected intercept survey and video observation data from 358 pedestrians across a total of 40 sites in two different cities. Structural equation models illustrated how pedestrians’ crossing-oriented satisfaction was shaped by their positive perceptions of safety and low levels of …

Risk-Based Methodology For Structural Evaluation Of Bridge-Sized Culverts, David Yang, Kevin White, Timothy Wood

Civil and Environmental Engineering Faculty Publications and Presentations

This report presents the results of the project sponsored by the Federal Highway Administration (FHWA), “Risk Based Methodology for Structural Evaluation of Bridge-Sized Culverts”. The goal of this project was to develop general methodology to (a) quantify uncertainty, especially live load uncertainty, unique to bridge-sized RC box culverts and (b) analyze and calibrate reliability of culverts rated under different rating loads. Over 344 combinations of culvert designs and backfill depths were analyzed based on the AASHTO Manual for Bridge Evaluation as well as the three-dimensional finite element models (FEMs) of the soil-culvert systems. For each combination, a wide range of …

Phase Of The Seabed Frequency-Domain Reflection Coefficient: Measurements And Modeling, Charles W. Holland

Electrical and Computer Engineering Faculty Publications and Presentations

The phase of the seabed frequency-domain reflection coefficient potentially contains valuable information on the geoacoustic properties in a layered/refracting seabed. However, heretofore, the phase has not been exploited. Measurements of phase are presented in an area of thick mud at the New England Mud Patch. In addition, a model is presented along with the modeling results. While this is only a first step towards understanding the potential value of exploiting the phase, it seems clear that in some instances, the phase not only contains valuable geoacoustic information, but carries a higher information content than the magnitude.

Introduction To The Special Issue On Verification And Validation Of Source And Propagation Models For Underwater Sounda), Kathleen J. Vigness-Raposa, Klaus Lucke, Michael A. Ainslie, Michele B. Halvorsen, Christ A. F. De Jong, Stanley J. Labak, Martin Siderius

Electrical and Computer Engineering Faculty Publications and Presentations

This joint Special Issue of JASA and JASA Express Letters focuses on underwater sound source and propagation modelling, both of ambient sound as well as sources of relevance to possible effects of sound on aquatic life, and corresponding acoustical metrics. Combining information on the sound field with information on a dose-effect relationship enables estimation of the potential effects. The Special Issue presents a collection of eighteen articles on the following topics: (1) verification of source and propagation models, (2) validation of source and propagation models, and (3) bioacoustical metrics for assessment of the risk of environmental effects. This special issue …

Structural Earthquake Resiliency Of Rocking Core Systems With Floor Enabled Recentering, S. Taban Hajimirza

Dissertations and Theses

The growing need for structural earthquake resiliency, coupled with increasing demands for environmentally sustainable construction, has driven architects and engineers to emphasize the importance of earthquake-resistant mass timber multistory construction in regions prone to high seismic activity. With advancements in building technologies, cross-laminated timber (CLT) has emerged at the forefront of this movement by unlocking new potentials for urban development.

Motivated by the aforementioned demands, this PhD dissertation investigated lateral behavior and earthquake response of a novel lateral force-resisting structural system, known as Floor Recentering Rocking Core (FLR-ROCR). FLR-ROCR is a low-damage recentering mass-timber system that leverages restoring interactions between …

Direct Graphene Growth On Low-Alloy And Mild Steel Surfaces Controlled By Carbon Solubility And Surface Microstructural Transformations During Chemical Vapor Deposition, Kaleb Hood, Nam Nguyen, Sebastian Lara, Adan Velasquez, Samuel Olson, Yi Xia, Jun Jiao

Mechanical and Materials Engineering Faculty Publications and Presentations

This study demonstrates for the first time, graphene grown directly on the iron-rich surfaces of bulk 8620 low-alloy and 1018 mild steel by chemical vapor deposition, a key step toward developing thin graphene coatings with strong graphene-steel bonding. Low growth temperatures of 660 °C–680 °C, were used to manipulate the steel's carbon solubility, confining carbon diffusion and microstructural transformations to the surface regions, with the bulk relatively unchanged. For 1018, a growth temperature of 680 °C resulted in a multilayer graphene coating with 80 % coverage. The alloying elements in 8620 improved graphene formation by influencing the surface microstructure transformations …

Identifying The Effect Of Architecture Morphology On Wind Fields And Pm2.5 Dispersion At The Urban Block Scale Via A Combined Scheme, Bin Guo, Lu Li, Xiaowei Zhu, Zheng Wang, Miaoyi Chen, Lin Pei, Tengyue Guo

Mechanical and Materials Engineering Faculty Publications and Presentations

This study explores the potential of architecture morphology to mitigate PM2.5 pollution through enhanced urban ventilation. Despite the recognized influence of building designs on wind and air pollution distribution at the urban block scale, specific mechanisms remain poorly understood. To address this gap, we have developed an integrative approach combining in-situ observations, Geographic Information System (GIS), Remote Sensing (RS), Computational Fluid Dynamics (CFD), and statistical modeling. Here, CFD simulates the flow field and PM2.5 dispersion, using in-situ observations for turbulence model selection. GIS quantify architecture morphology parameters to establish accurate CFD boundary conditions, ensuring simulations reflect real-world conditions and precise …

Identification And Analysis On Surface Deformation In The Urban Area Of Nanchang Based On Ps-Insar Method, Mengping Zhang, Jiayi Pan, Peifeng Ma, Hui Lin

Civil and Environmental Engineering Faculty Publications and Presentations

Interferometric Synthetic Aperture Radar (InSAR) technology has emerged as a vital tool for monitoring surface deformation due to its high accuracy and spatial resolution. With the rapid economic development of Nanchang, extensive infrastructure development and construction activities have significantly altered the urban landscape. Underground excavation and groundwater extraction in the region are potential contributors to surface deformation. This study utilized Sentinel-1 satellite data, acquired between September 2018 and May 2023, and applied the Permanent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) technique to monitor surface deformation in Nanchang’s urban area. The findings revealed that surface deformation rates in the study area …

Turbulent Structures In Coupled Wind-Wave Flows, Cerrina Mouchref

Dissertations and Theses

The interactions between wind and waves in offshore environments are complex and have yet to be fully understood. Analyzing these interactions is motivated by an increased interest in climate modeling and the deployment of offshore construction, such as offshore wind farms. In this study, experiments are performed in a wind tunnel using particle image velocimetry (PIV) to analyze wind-wave interactions over various wave and wind speeds. The addition of the wave, a moving boundary, leads to the use of Reynolds triple decomposition in order to separate the turbulent and wave-phase coherent fluctuations. A curvilinear coordinate system was used to analyze …

Effects Of The Upwind Spanwise Heterogeneous Terrain On The Wind Resource Distribution, Haosen H.A. Xu, Tianxiang Yu, Raúl Bayoán Cal, Xiaowei Zhu

Mechanical and Materials Engineering Faculty Publications and Presentations

Wind energy has become increasingly crucial among renewable energy resources, and as the prerequisite for effective wind energy utilization, accurate wind resource assessments are hence prominent. Topography significantly affects near-surface wind fields and is thus an essential factor to be considered for wind resource assessment. However, few studies have addressed the wind resource distribution downwind of spanwise-heterogeneous terrains, which are frequently encountered in both natural and urban environments. To fill this gap, large eddy simulations were performed to investigate wind distributions over a uniform terrain downwind of terrains featuring spanwise-alternating strips of low and high surface roughness, and the high …

Largely Enhanced Out-Of-Plane Electromechanical Coupling Effects In Two-Dimensional Molybdenum-Disulfide/Boron-Nitride Heterostructures, Qiong Liu, Vijay Kumar Choyal, James E. Morris, Timon Rabczuk, Xiaoning Jiang, Xiaoying Zhuang

Electrical and Computer Engineering Faculty Publications and Presentations

The electromechanical coupling effects in two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted great interest. However, for 2D TMDs, piezoelectricity is confined to the basal plane, and the flexoelectricity-derived out-of-plane electromechanical response is usually faint, limiting the applications of this material family using the out-of-plane electromechanical effects. Here, this work reports a facile strategy to greatly enhance the out-of-plane electromechanical response of hexagonal molybdenum disulfide (2H-MoS₂) nanoflakes by stacking monolayer hexagonal boron nitride (h-BN) on 2H-MoS₂ nanoflakes to form MoS₂/BN heterostructures. The d^eff/₃₃ coefficient of MoS₂/BN can reach a value comparable …