Mechanical Engineering - Research Publications

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http://hdl.handle.net/11343/359

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Conversion of Upper-Limb Inertial Measurement Unit Data to Joint Angles: A Systematic Review.

Fang, Z ; Woodford, S ; Senanayake, D ; Ackland, D (MDPI AG, 2023-07-19)

Inertial measurement units (IMUs) have become the mainstay in human motion evaluation outside of the laboratory; however, quantification of 3-dimensional upper limb motion using IMUs remains challenging. The objective of this systematic review is twofold. Firstly, to evaluate computational methods used to convert IMU data to joint angles in the upper limb, including for the scapulothoracic, humerothoracic, glenohumeral, and elbow joints; and secondly, to quantify the accuracy of these approaches when compared to optoelectronic motion analysis. Fifty-two studies were included. Maximum joint motion measurement accuracy from IMUs was achieved using Euler angle decomposition and Kalman-based filters. This resulted in differences between IMU and optoelectronic motion analysis of 4° across all degrees of freedom of humerothoracic movement. Higher accuracy has been achieved at the elbow joint with functional joint axis calibration tasks and the use of kinematic constraints on gyroscope data, resulting in RMS errors between IMU and optoelectronic motion for flexion-extension as low as 2°. For the glenohumeral joint, 3D joint motion has been described with RMS errors of 6° and higher. In contrast, scapulothoracic joint motion tracking yielded RMS errors in excess of 10° in the protraction-retraction and anterior-posterior tilt direction. The findings of this study demonstrate high-quality 3D humerothoracic and elbow joint motion measurement capability using IMUs and underscore the challenges of skin motion artifacts in scapulothoracic and glenohumeral joint motion analysis. Future studies ought to implement functional joint axis calibrations, and IMU-based scapula locators to address skin motion artifacts at the scapula, and explore the use of artificial neural networks and data-driven approaches to directly convert IMU data to joint angles.
Evaporation induced convection enhances mixing in the upper ocean

Falor, D ; Gayen, B ; Sengupta, D ; Ivey, GN (FRONTIERS MEDIA SA, 2023-05-16)

The upper ocean surface layer is directly affected by the air-sea fluxes. The diurnal variations in these fluxes also cause the upper ocean mixed layer turbulence and mixing to diurnally vary. The underlying thermohaline structure also varies accordingly throughout the day. Here we use large-eddy simulation to quantify the role of surface evaporation in modulating the diurnal mixed layer turbulence and mixing in the presence of wind forcing. During daytime, the upper ocean boundary layer becomes thermally stratified, and a salinity inversion layer is formed in the upper 10m, leading to double diffusive salt-fingering instability. During nighttime, the mixed layer undergoes convective deepening due to surface buoyancy loss redfrom both surface cooling and evaporation. We find that salinity makes a major contribution to the convective instability during both transitions between day and night. Overall surface evaporation increases the mixed layer depth and irreversible mixing through convection, both during nighttime and daytime, and leads to better prediction of the dynamical variables as sea surface salinity (SSS) and sea surface temperature (SST). Our findings can help improve the ocean parameterizations to improve the forecasts on a diurnal timescale.
High-Fidelity Computational Assessment of Aero-Thermal Performance and the Reynolds' Analogy for Additively Manufactured Anisotropic Surface Roughness

Jelly, TO ; Abu Rowin, W ; Hutchins, N ; Chung, D ; Tanimoto, K ; Oda, T ; Sandberg, RD (ASME, 2023-11-01)

Abstract Direct numerical simulations of incompressible turbulent forced convection over irregular, anisotropic surface roughness in a pressure-driven plane channel flow have been performed. Heat transfer was simulated by solving the passive scalar transport equation with Prandtl number Pr = 0.7. The roughness topographies under investigation here are based on an X-ray computed tomography scan of an additively manufactured internal cooling passage, which had an irregular, multiscale and mildly non-Gaussian height distribution. Three different roughness topographies and three different friction Reynolds numbers (Reτ = 395, 590, 720) were considered, along with reference smooth-wall simulations at matched Reτ. By systematically varying the roughness topography and flow conditions, a direct computational assessment of aero-thermal performance (pressure losses and heat transfer) and the Reynolds analogy factor, i.e., 2Ch/Cf, where Ch is the heat-transfer coefficient (Stanton number) and Cf is the skin-friction coefficient, was conducted. The results highlight the profound impact that the roughness orientation (relative to the flow direction) has upon the aero-thermal performance of additively manufactured internal passages, with transverse-aligned roughness augmenting heat transfer by as much as 33%, relative to its streamwise-aligned counterpart. An interrogation of velocity and temperature statistics in the near-wall region was also performed, which underlined the growing dissimilarity between heat transfer and drag as fully rough conditions are approached.
A Distributed Coordination Approach for the Charge and Discharge of Electric Vehicles in Unbalanced Distribution Grids

Nimalsiri, N ; Ratnam, E ; Smith, D ; Mediwaththe, C ; Halgamuge, S (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2023-01-01)
Using ferroelastic variant switching to tune ferromagnetic properties of 1T' CrX₂ (X = S, Se) for local strain modulated spin valves

Chen, K ; Deng, J ; Huo, W ; Kan, D ; Shi, Q ; Song, M ; Zhao, X ; Yang, S ; Liu, JZ (AMER PHYSICAL SOC, 2023-01-19)
Robust Admittance Control With Complementary Passivity

Xu, J ; Chen, X ; Tan, Y ; Zou, W (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2023)
Strain-aided room-temperature second-order ferroelectric phase transition in monolayer PbTe: Deep potential molecular dynamics simulations

Gong, Z ; Liu, JZ ; Ding, X ; Sun, J ; Deng, J (American Physical Society (APS), 2023-10-01)
Nitrogen rejection in natural gas using NaZSM-25 zeolite

Mousavi, SH ; Tamnanloo, J ; Mokarizadeh, AH ; Zavabeti, A ; Liu, JZ ; Li, GK (ROYAL SOC CHEMISTRY, 2023-07-12)

Natural gas reservoirs usually contain considerable amounts of nitrogen (N2). Methane (CH4) as the main component in natural gas must be purified before transferring to the pipeline or storing as liquified natural gas (LNG). Currently, energy-intensive cryogenic distillation is the only industrial approach for N2 rejection in natural gas. The adsorption process based on a N2-selective adsorbent can minimize the separation cost. However, the search for an adsorbent that can selectively reject N2 in natural gas has lasted for decades. Here, we report a microporous zeolite called NaZSM-25 capable of adsorbing N2 over CH4 with an exceptional selectivity of 47 at room temperature that outperforms all previously known N2-selective adsorbents. At 295 K and 100 kPa, the N2 and CH4 uptakes on NaZSM-25 were 0.25 and 0.005 mmol g-1, respectively. CH4 showed negligible external surface adsorption in the whole temperature range of 273-323 K. Theoretical studies through replica exchanged Monte Carlo, molecular dynamics, and ab initio density functional theory (DFT) proved the diffusion limitation of CH4 as a result of 8-membered ring (8MR) pore opening deformation by Na+ cation. The DFT results showed the diffusion energy barriers of 63 and 96 kJ mol-1 for N2 and CH4, respectively, when passing an 8MR occupied with a Na+. NaZSM-25 is a promising adsorbent to be utilized in a pressure swing adsorption process at room temperature to minimize the energy consumption in N2 rejection units.
Bio-informed materials: three guiding principles for innovation informed by biology

Stuart-Fox, D ; Ng, L ; Elgar, MA ; Holtta-Otto, K ; Schroder-Turk, GE ; Voelcker, NH ; Watson, GS (NATURE PORTFOLIO, 2023-09)
Dynamic topological domain walls driven by lithium intercalation in graphene

Endo, Y ; Yan, X ; Li, M ; Akiyama, R ; Brandl, C ; Liu, JZ ; Hobara, R ; Hasegawa, S ; Wan, W ; Novoselov, KS ; Tang, W-X (NATURE PORTFOLIO, 2023-10)

Stacking engineering in van der Waals (vdW) materials is a powerful method to control topological electronic phases for quantum device applications. Atomic intercalation into the vdW material can modulate the stacking structure at the atomic scale without a highly technical protocol. Here we report that lithium intercalation in a topologically structured graphene/buffer system on SiC(0001) drives dynamic topological domain wall (TDW) motions associated with stacking order change by using an in situ aberration-corrected low-energy electron microscope in combination with theoretical modelling. We observe sequential and selective lithium intercalation that starts at topological crossing points (AA stacking) and then selectively extends to AB stacking domains. Lithium intercalation locally changes the domain stacking order to AA and in turn alters the neighbouring TDW stacking orders, and continuous intercalation drives the evolution of the whole topological structure network. Our work reveals moving TDWs protected by the topology of stacking and lays the foundation for controlling the stacking structure via atomic intercalation. These findings open up new avenues to realize intercalation-driven vdW electronic devices.

Mechanical Engineering - Research Publications

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