Recent ucbmecheng items

On the scaling of air entrainment from a ventilated partial cavity

Fri, 18 Sep 2026 00:00:00 +0000

Abstract The behaviour of a nominally two-dimensional ventilated partial cavity was examined over a wide range of size scales and flow speeds to determine the influence of Froude, Reynolds, and Weber number on the cavity shape, dynamics, and gas entrainment rate. Two geometrically similar experiments were conducted with a 14:1 length scale ratio. The results were compared to a two-dimensional semi-analytical model of the cavity flow, and Froude scaling was found to be sufficient to match basic cavity shapes. However, the air flux required to maintain a stable cavity did not scale with Froude number alone, as the dynamics of the cavity closure changed with increasing Reynolds number. The required air flux differed over one order of magnitude between the lowest and highest Reynolds number flows. But, for sufficiently high Reynolds numbers, the rate of scaled entrainment appeared to approach Reynolds number independence. Modest changes in surface tension of the...

Towards robust laser beam propagation in atmospheric turbulence

Tue, 1 Sep 2026 00:00:00 +0000

High-fidelity optical propagation through the atmosphere is essential for free-space optical technologies, including laser-based remote sensing and optical communication. However, atmospheric turbulence severely distorts beams and compromises system performance. In this work, we employ hypergeometric-Gaussian (HyGG) vortex beams as probes to characterize and mitigate atmospheric turbulence. Using over 250,000 experimental and simulated frames, we show that refining the power spectrum density (PSD) can reduce numerical prediction errors by up to 79.8%. Concurrently, experimental observations supported by numerical simulations demonstrate that HyGG beams exhibit superior turbulence resilience across multiple metrics compared to conventional Gaussian beams, particularly in their ability to withstand over 5 times stronger turbulence while maintaining similar intensity fluctuations. These dual investigations, on both turbulence mitigation and robust beam solutions, converge to form...

Simple device modification simultaneously enhances indoor passive evaporative cooling power and duration

Tue, 1 Sep 2026 00:00:00 +0000

Passive evaporative cooling from a damp cloth or vessel can be used for localized cooling of perishables such as food and medicine, drinking water, and even people. Such applications have two key objectives, which are normally in tension with each other: minimizing the water consumption rate and maximizing the cooling (steady-state temperature swing between the cool cloth and the warm surroundings). Here, we present a simple device that delivers higher performance in both metrics simultaneously by adding a perforated aluminum foil sheet suspended over a stagnant air layer to thermally shield the evaporating surface while also facilitating mass transfer. Experimental results demonstrate a simultaneous 10%–25% increase in temperature swing and 2–3× reduction in water consumption rate as compared to conventional evaporative cooling. This improvement is achieved through careful modeling to optimize the coupled heat and mass transfer through the airgap (thermally insulating and vapor...

Ultrafast Nanoimaging of Carrier Funneling in Composition-Graded Semiconductor Nanowires

Tue, 1 Sep 2026 00:00:00 +0000

Recent advances in bandgap engineering of low-dimensional semiconductors have enabled high-efficiency carrier transport in miniaturized electronic and optoelectronic devices. The physical properties and functionalities of these materials are governed by complex carrier dynamics coupled with multiple transport mechanisms in tailored band structures. Here, we report ultrafast nanoimaging of carrier funneling and recombination in composition-grade CdS_xSe_1-x nanowires using pump-probe near-field nanoscopy. Leveraging the high resolution of this technique in both space and time, we resolve nanoscale local carrier dynamics along composition-graded nanowires, revealing the local variation of composition-dependent carrier mobilities and lifetimes that significantly differ from their uniform composition counterparts. Furthermore, we demonstrate a length-dependent behavior wherein shorter nanowires exhibit enhanced funneling effects, accelerating carrier...

Burst delay line for generating ultrashort pulse bursts with interval tunability from femtoseconds to nanoseconds.

Tue, 1 Sep 2026 00:00:00 +0000

Ultrashort burst laser pulses are important for applications in laser processing and spectroscopy. However, existing burst generators face limitations in pulse time interval tunability and coaxiality. Here, we present a burst pulse generator that delivers coaxial ultrashort pulses with tunable pulse time intervals using a single translation stage. The constructed system produced eight femtosecond pulses with uniform intervals tunable from 100 fs to 1.93 ns, equivalent to burst-internal repetition rates spanning 10 THz to 0.52 GHz. We further demonstrated interval-dependent plasma emission in air filamentation, providing a compact platform to study burst-laser-induced phenomena.

Nanoscale Compositional and Strain Gradients Enable High‐Speed and Amplitude‐Resolved Pyroelectric Sensing

Tue, 1 Sep 2026 00:00:00 +0000

The frequency response of pyroelectric sensors is fundamentally governed by thermal time constant (τ_th, determined by thermal mass and thermal conductance) and electrical impedance arising from film capacitance and readout circuit. Conventional bulk LiTaO₃ detectors are optimized for high responsivity at low modulation frequencies (0.1-10 Hz), possessing a large τ_th that thermally averages rapid temperature oscillations at elevated modulation frequencies, limiting fidelity in resolving dynamic varying thermal signals. Here, compositional and strain gradients are introduced into 100-nm-thick relaxor-ferroelectric films reducing τ_th to ≈2 µs and producing built-in potentials (≈1.45 V or 145 kV cm^-1) that enhance the pyroelectric coefficient and suppress the dielectric constant. This enables complementary dual-mode operation by enhancing current-mode electrical responsivity and improving the voltage-mode figure...

Bio-inspired micro-architected mechanochromic materials with radiative signature modulation

Mon, 31 Aug 2026 00:00:00 +0000

Drawing inspiration from the panther chameleon's sophisticated color-adaptive abilities, we introduce a unified design framework for a new class of bio-inspired mechanochromic materials with tailored reflectivity across the electromagnetic spectrum. While structural coloration in nature relies on the mechanical adjustment of photonic crystal spacing, engineering such systems is often hindered by the barreling effect, the lateral bulging of bulk materials caused by Poisson's effect. To address this, we developed a mechanical metamaterial substrate optimized through a genetic algorithm and modeled it using Timoshenko beam theory to ensure a uniform strain field during deformation. The proposed system features a two-dimensional hexagonal lattice of composite dielectric nanopillars positioned on top of a micro-architected substrate fabricated via Multiphoton Lithography (MPL). The nanopillars consist of an MPL core coated with a high-refractive-index material to achieve complete...

Prediction of Metastable States for Throttling in Pressure Relief Valves for Sustainable CO₂ Heat Pump Technologies

Mon, 31 Aug 2026 00:00:00 +0000

Abstract: Incorporating carbon dioxide (CO2) refrigerant into the heat pump (HP) technology can reduce climate change effects due to working fluid loss. However, CO2 refrigerants in an HP system may change from a gaseous state to a liquid or solid “snow” during the throttling and pressure-relief valve processes, which may block downstream flow in pipes and cause unsafe operation issues. This paper describes a Soave–Redlich–Kwong (SRK) statistical-thermodynamics-based model to predict CO2 refrigerant metastable state properties (enthalpy, temperature, and volume) exhibited during throttling through a leakage path or pressure relief valve in HP technologies. In addition, the simulation can predict changes in density fluctuations states exhibited during the process that can indicate an impending phase change and can predict exit state conditions for widely varying supercritical initial equilibrium states. Results indicate that when a constant enthalpy throttling...

Optimized mechano-fluidic metamaterials inspired by deep-sea sponges

Mon, 31 Aug 2026 00:00:00 +0000

Multifunctional materials that balance mechanical resilience and fluid dynamic efficiency are critical in engineering applications, yet their synergistic optimization remains challenging due to inherent trade-offs, computational expense, and high-dimensional design spaces. Inspired by the skeleton of the deep-sea sponge Euplectella aspergillum, this work presents an automated framework integrating Finite Element Analysis for mechanics, Computational Fluid Dynamics for flow behavior, and multi-objective Bayesian optimization. Leveraging high-performance computing, the framework efficiently explores complex design spaces to identify Pareto-optimal solutions. Optimized lattices achieve an average 140% increase in critical buckling load across a range of volume fractions relative to baseline designs, while simultaneously reducing drag, lift, and vortex shedding at porosities as low as 5%. We fabricate selected designs via stereolithography and validate them through compression experiments...

Capillary Leidenfrost effect

Mon, 31 Aug 2026 00:00:00 +0000

The Leidenfrost effect, best known as the formation of an insulating vapour layer beneath a liquid droplet that delays boiling, offers great potential for droplet manipulation and drag reduction. However, regulating the conventional Leidenfrost effect remains challenging due to the complex liquid dynamics involved. Here we report a behaviour that we term the capillary Leidenfrost effect, which enables stable and sustained solid levitation driven by liquid evaporation. It occurs at a temperature threshold that is below the Leidenfrost point of its droplet counterpart, yet without the need for specialized surface manufacturing techniques. Our structure is composed of periodically arranged capillaries that stabilize the liquid interface, enhance heat conduction and provide liquid storage capacities. The capillary Leidenfrost effect is generic in widely accessible natural materials and metals. Our experiments demonstrate the feasibility of long-distance, sustained self-propulsion...

Nanoengineering Scalephobic Surfaces for Liquid Cooling Enhancement

Mon, 31 Aug 2026 00:00:00 +0000

Abstract Crystallization fouling, a process where mineral scales form on surfaces, is of broad importance in nature and technology, negatively impacting water treatment and electricity production. However, a rational methodology for designing materials with intrinsic resistance to scaling and scale adhesion remains elusive. Here, guided by nucleation physics, this work investigates the effect of coating composition and surface structure on the nucleation and growth mechanism of scale on metallic heat transfer surfaces nanoengineered by large‐area techniques. This work observes that on hydrophilic nanostructured copper, despite its significantly enlarged surface area compared to smooth surfaces, scale formation is substantially suppressed leading to sustained, efficient cooling performance. This work reveals the mechanism through thermofluidic modeling coupled with in situ optical characterization and show that surface bubble formation through degassing is responsible for generating...

Operando Depth-Resolved Measurement of Solvation Entropy, Interfacial Transport, and Charge-Transfer Kinetics in Lithium-Ion Batteries

Wed, 15 Jul 2026 00:00:00 +0000

Understanding and improving the performance and longevity of lithium-ion batteries critically depends on insight into the dynamic processes occurring at buried electrode-electrolyte interfaces. However, direct, depth-resolved, and operando diagnosis of these interfaces remains a longstanding challenge due to their inaccessibility beneath bulk materials, the limitations of conventional surface- and bulk-sensitive characterization tools, and the difficulty of maintaining realistic cell environments during measurement. These challenges have made it nearly impossible to uniquely resolve important interfacial properties such as charge transfer resistance, SEI (solid electrolyte interphase) resistance, and solvation entropy at the individual electrode interfaces within a working cell, information that is essential for mechanistic insight and accelerated battery design. Here, we report the development of multiharmonic electro-thermal spectroscopy (METS), an operando technique that enables...

Reflection and backscattering of IR light from free space laser plasmas in air

Wed, 15 Jul 2026 00:00:00 +0000

Reflection and backscattering of IR light from free space laser plasmas in air

Reflection and Scattering of Infrared Radiation from Free Space Laser Breakdown in Air

Wed, 15 Jul 2026 00:00:00 +0000

Ultrafast lasers are empowering tools for standoff material analysis. Here, we explore the use of laser produced plasmas as remotely-generated free space reflection and scattering elements to dramatically enhance infrared spectral signature collection.

Free space laser plasmas as scattering and reflection elements for standoff IR spectroscopy

Wed, 15 Jul 2026 00:00:00 +0000

Free space laser plasmas as scattering and reflection elements for standoff IR spectroscopy

Demonstration and analysis of volumetric additive manufacturing via sub-orbital spaceflight testing

Tue, 7 Jul 2026 00:00:00 +0000

Computed Axial Lithography (CAL) represents a significant advancement in the emerging field of Volumetric Additive Manufacturing (VAM). CAL addresses key limitations of traditional photopolymer additive manufacturing technologies, by eliminating the need for layering and support structures. Unlike conventional methods, CAL prints components by illuminating all points within a desired geometry simultaneously, using tomographic reconstruction to form the object in a single step. This unique approach eliminates the relative motion between the object and the precursor material, enabling faster printing speeds and reducing the waste associated with support structures. However, CAL parts require post-processing steps before they can be utilized. CAL's core attributes make it particularly suited for In-Space Manufacturing (ISM), due to its fast fabrication times, wide breadth of materials it can use, and minimized footprint. CAL has been successfully demonstrated in microgravity during...

Unlocking the Future of Aircraft Manufacturing: The Environmental Benefits of Laser Patterning for Surface Enhancement of Aircraft-Certified Alloys

Tue, 23 Jun 2026 00:00:00 +0000

Surface protection and functional modification of aircraft-certified aluminum alloys are essential for corrosion resistance, durability, and long-term airworthiness. At the same time, increasingly restrictive environmental regulations motivate the development of alternatives to legacy wet-chemical surface treatments. This study presents an integrated assessment of ultrafast femtosecond laser surface texturing as a surface functionalization approach for Aluminum 6061 alloys within an aerospace manufacturing and sustainability context. Ultrashort-pulse laser processing enables controlled micro- and nano-scale surface topographical modification with limited thermal impact, allowing adjustment of wettability and surface functionality while preserving bulk material integrity. As a dry and contactless process, femtosecond laser treatment eliminates the use of hazardous chemicals, reduces consumable inputs, and generates minimal secondary waste. A streamlined cradle-to-gate life cycle...

Sex-Based Differences in Cell Types and Gene Expression within the Anterior Cruciate Ligament

Sun, 21 Jun 2026 00:00:00 +0000

BACKGROUND: Sex-based disparities remain a major challenge in musculoskeletal medicine. Women and men experience different anterior cruciate ligament (ACL) injury rates and severity, but the causes remain unclear. We hypothesized that cellular differences in human progenitor cells contribute to the higher ACL tear risk observed in females. METHODS: ACL samples were collected from 4 male and 5 female patients undergoing ACL reconstruction surgery. Live cells were collected through flow cytometry and sent for single-cell RNA sequencing. Significantly greater expression in either sex relative to the other was defined as a >25% increase in expression level (log 2 fold change > 0.32) and p < 0.05). Subpopulation characterization was performed with immunofluorescence on tissue sections. RESULTS: We discovered sex-based differences in all of the native cell types within the ACL. In particular, fibroblast progenitor-like (TPPP3+) cells from female patients expressed genes associated...

Jellyfish-Inspired Ultrafast and Versatile Magnetic Soft Robots for Biomedical Applications

Wed, 22 Apr 2026 00:00:00 +0000

Achieving rapid and adaptive locomotion in soft robots is essential for navigating complex environments and enabling diverse real-world functions. Here, we present a jellyfish-inspired magnetic soft robot (J-MSR) capable of ultrafast swimming and seamless multimodal motion transitions in liquid environments. By employing an asymmetric trapezoidal magnetic field waveform for actuation, the J-MSR capitalizes on spatial and temporal asymmetries during its swimming cycle, mimicking the natural propulsion mechanism of jellyfish. Through magnetic-fluid-solid multiphysical field coupling analysis and magnetic field waveform optimization, the J-MSR achieves a remarkable swimming speed of 14.85 body lengths per second, demonstrating notably enhanced propulsion performance compared with previously reported jellyfish-inspired robots. Unlike traditional designs relying on auxiliary buoyancy structures, the J-MSR demonstrates versatile multimodal motions under natural negative buoyancy conditions,...

Surface Flow Characterization of Fires Under the Combined Effect of Slope and Wind

Tue, 21 Apr 2026 00:00:00 +0000

During wildland fire spread both slope and wind act together to modify fire dynamics, commonly accelerating the rate of fire spread. To investigate this coupling effect, flow field measurements were conducted on stationary gaseous fires produced over a tilt table in a wind tunnel, with fireline intensities ranging from 41 to 123 kW/m. The angle of inclination (θ) and the wind speed (V) were varied from 0 to 30° and 0.30 to 1.27 m/s, respectively. The surface gas velocity of the fire at various downstream locations was measured using temperature-correlation velocimetry (TCV), which was enabled using streamwise temperature signals from an array of micro-thermocouples. The effect of the slope was converted to an equivalent surface velocity, $$\:{U}_{slope}$$, following the concept of fire-induced flow over an inclined surface. A momentum analysis was conducted to isolate the coupling effect of slope and wind based on $$\:{U}_{slope}$$, V, and the mean measured surface gas...

Quantum Sensing in Micro-Architected Scaffolds

Wed, 18 Mar 2026 00:00:00 +0000

Quantum sensing with nitrogen-vacancy centers in diamond has emerged as a powerful tool for measuring diverse physical parameters, yet the versatility of these measurement approaches is often limited by the achievable layout and dimensionality of bulk-crystal platforms. Here, we demonstrate a versatile approach to creating designer quantum sensors by surface-functionalizing multiphoton lithography microstructures with NV-containing nanodiamonds. We showcase this capability by fabricating a 150 μm × 150 μm × 150 μm triply periodic minimal surface gyroid structure with millions of attached nanodiamonds. We demonstrate a means to volumetrically image these structures using a refractive index matching confocal imaging technique and extract ODMR spectra from 1.86 μm × 1.86 μm areas of highly concentrated nanodiamonds across a cross-section of the gyroid. Furthermore, the high density of sensing elements enables ensemble temperature measurements with a sensitivity of 0.548 ± 0.084 K/√Hz...

Looking at endometriosis–diagnosis and disease mechanisms through a mechanical lens

Wed, 11 Mar 2026 00:00:00 +0000

Endometriosis is a chronic gynecological disorder marked by the growth of endometrial-like tissue outside the uterus, often resulting in pain and infertility and affecting overall quality of life. Despite its prevalence, diagnostic delays persist due to reliance on invasive laparoscopy and the lack of sensitive, specific, non-invasive biomarkers. Current molecular and imaging tools have improved detection but remain limited, underscoring the need for new diagnostic strategies. This review introduces a mechanobiological perspective, exploring how cellular biophysical properties such as cell stiffness, deformability, and contractility can potentially serve as functional biomarkers for endometriosis. We examine lesion subtypes, menstrual cycle dynamics, and key biological processes such as decidualization, epithelial-mesenchymal transition (EMT), and stromal remodeling through a mechanical lens. Parallels are drawn between endometriosis and cancer to underscore the diagnostic potential...

Premature transition to supercritical flow with bubbly flow around a circular cylinder

Tue, 10 Feb 2026 00:00:00 +0000

Vortex induced vibration (VIV) experienced during flow past a cylinder can reduce equipment performance and in some cases lead to failure. Previous studies have shown that the shift in shedding frequency and vibration amplitude under the influence of gas injection at the upper subcritical range can produce a premature shift to supercritical flow (and the drag crisis). To date, the influence of the gas distribution along the cylinder span has not yet been investigated. Time-resolved particle image velocimetry (TR-PIV), proper orthogonal decomposition (POD) and spectral proper orthogonal decomposition (SPOD) of the wake structures, as well as bubble image velocimetry (BIV) are used to assess the flow topology changes under the influence of spanwise uniform and spanwise discontinuous gas injection. We demonstrate that for gas injected along the span of the cylinder, a premature shift to supercritical flow occurs even at volumetric qualities of 0.034%, which is lower than has been...

High-emissivity, thermally robust emitters for high power density thermophotovoltaics

Mon, 22 Dec 2025 00:00:00 +0000

Thermal radiative energy transport is essential for high-temperature energy harvesting technologies, including thermophotovoltaics (TPVs) and grid-scale thermal energy storage. However, the inherently low emissivity of conventional high-temperature materials constrains radiative energy transfer, thereby limiting system performance and technoeconomic viability. Here, we demonstrate ultrafast femtosecond laser-material interactions to transform diverse materials into near-blackbody surfaces with broadband spectral emissivity above 0.96. This enhancement arises from hierarchically engineered light-trapping microstructures enriched with nanoscale features, effectively decoupling surface optical properties from bulk thermomechanical properties. These laser-blackened surfaces (LaBS) exhibit exceptional thermal stability, retaining high emissivity for over 100 h at temperatures exceeding 1,000°C, even in oxidizing environments. When applied as TPV thermal emitters, Ta LaBS double electrical...

Simultaneous Heat and Electricity Storage in a Flow Battery System

Wed, 17 Dec 2025 00:00:00 +0000

This study investigates the dual-storage capability of a redox flow battery (RFB) system, enabling simultaneous storage of heat and electricity within a single platform. Through electrochemical and thermal experiments, we evaluated how heat storage affects battery performance and vice versa using a counterflow heat exchanger integrated in a conventional RFB configuration. The results show that incorporating heat storage had a minimal impact on the electrochemical charging and discharging processes. Further, the heat discharge operated independently of electrochemical storage, confirming that both functions can coexist without interference. The combined system also enhanced overall energy conversion efficiency, demonstrating its potential as an efficient solution for supplying both thermal and electrical energythe two most widely used energy forms.

Solid-state batteries enabled by ultra-high-frequency self-heating

Tue, 16 Dec 2025 00:00:00 +0000

Solid-state batteries (SSBs) are promising next-generation batteries due to their high energy density and enhanced thermal stability and safety. However, their sluggish kinetics and transport at room temperature result in high internal impedance and critically reduce the attainable discharge energy density. Taking advantage of their strong temperature-dependent ionic conductivity, here we introduce ultra-high-frequency (greater than 105 Hz) self-heating (UHFSH) of SSBs, which can rapidly warm up the batteries from room temperature to operating temperature (∼65°C) in less than a minute. As proof of concept, UHFSH experiments were conducted on symmetric solid-state cells with lithium aluminum germanium phosphate electrolyte in different configurations. Using an experimentally validated model, pack-level simulations predict fast heating (50 K/min) and minimized heating energy consumption (less than 4%). Without any modification of the materials or structure of the batteries, our...

Multi-target digital material design via a conditional denoising diffusion probability model

Wed, 19 Nov 2025 00:00:00 +0000

Multi-target digital material design has been challenging due to the expansive design space and instability of traditional methods in satisfying multiple objectives. This work proposes and demonstrates a customizer based on a classifier-free, conditional denoising diffusion probability model (cDDPM) to efficiently create the layouts of digital materials meeting the design goal of multiple mechanical properties all together. A case study has been conducted based on a micro mechanical resonator with four pre-assigned resonant frequencies. Using 29,430 samples generated via finite element analysis (FEA), the cDDPM is trained to simultaneously customize up to four vibrational modes, achieving over 95% prediction accuracy. Furthermore, the cDDPM approach also shows superior performances in the single-target customization for up to 99% in prediction accuracy when compared with traditional conditional generative adversarial networks (cGANs). As such, the proposed design framework provides...

Milli-Scale AcousTac Sensing Using Soft Helmholtz Resonators

Tue, 21 Oct 2025 00:00:00 +0000

Acoustic transmission, or sound, can effectively communicate information over distances through various media. We focus on generating acoustic transmission using pneumatically driven resonators for wireless tactile sensing without the need for any electronics at the end-effector or contact point. We explore the relationship between emitted frequency and the geometry of the resonance chamber. When a normal compressive force is applied to the end cap, the compliant resonant cavity deforms, leading to an increase in frequency measurable by an external microphone. Prior work uses tube resonators with fipple attachments. In the present work, we study whether a different smaller audible cylindrical resonator with air blown across the entryway can be utilized instead. We test the utility of the Helmholtz resonator model in predicting the experimental frequency response. Resonance is often modeled for rigid cavities, presenting unique challenges in predicting resonance for the design...

Continuum framework for multiscale contact mechanics of elastic-plastic fractal interfaces with intervening boundary film

Wed, 24 Sep 2025 00:00:00 +0000

A comprehensive mechanics theory was developed to analyze multiscale contact and friction behavior of elastic-plastic fractal surfaces coated with a boundary film. This approach accounts for the size-dependent behavior of asperity microcontacts that arise from the inherent roughness of fractal topographies. To capture the fundamental mechanisms governing interfacial friction, representative single-asperity models were formulated to describe both elastic and plastic deformation modes at the microscale. These models were then systematically extended across the entire asperity population, enabling an accurate representation of contact interactions over a broad range of length scales. In the elastic regime, frictional resistance is primarily attributed to shearing of the boundary film between opposing asperities. Conversely, in the plastic regime, asperities indent and plow through the softer counterface material, while the boundary film remains attached to the deformed surface contributing...

Seismic Response Prediction of Degrading Structures

Wed, 10 Sep 2025 00:00:00 +0000

Seismic Response Prediction of Degrading Structures

Characterization of the murine spine for spaceflight studies

Mon, 7 Jul 2025 00:00:00 +0000

Rodents provide a useful analog for understanding the effects of spaceflight on the human body, offering opportunities for investigations into the relationship between microgravity and the musculoskeletal system. In particular, rodents have often been utilized to improve our understanding of the effects of spaceflight on the spine, including intervertebral disc and vertebral body health. However, there are a number of experimental factors that differ between existing works, including mission duration, animal housing, and anatomical location of interest, making it difficult to draw holistic conclusions. Additionally, the quadrupedal nature of the murine spine results in different biomechanical loading than in a bipedal organism. Thus, the objective of this study was to more fully define the bulk properties of the murine lumbar spine model after 28 days of spaceflight. Additionally, the proximal tibia was analyzed to provide insight into the skeletal site-specificity of gravitational...

Surface-Tailoring and Morphology Control as Strategies for Sustainable Development in Transport Sector

Tue, 24 Jun 2025 00:00:00 +0000

Surface wetting plays an important role in the corrosion protection processes of aerospace applications. Here, we demonstrate the use of ultrafast femtosecond (fs) laser processing techniques to tailor the wetting properties of aluminum (Al) substrates by creating diverse surface morphologies. Specifically, two distinct laser scanning methods—dot-hatching and cross-hatching—were employed to fabricate microstructures on the substrates. By varying the incident laser parameters, we confirmed that the resulting surface morphologies exhibit different wetting behaviors, spanning from hydrophilicity to hydrophobicity. Furthermore, time-resolved spreading tests validate that dynamic wetting behaviors can also be modified. This fs laser processing approach provides a straightforward, one-step fabrication method for effectively modifying the wetting properties of Al alloys.

Halide perovskites enable polaritonic XY spin Hamiltonian at room temperature

Tue, 17 Jun 2025 00:00:00 +0000

Exciton polaritons, the part-light and part-matter quasiparticles in semiconductor optical cavities, are promising for exploring Bose–Einstein condensation, non-equilibrium many-body physics and analogue simulation at elevated temperatures. However, a room-temperature polaritonic platform on par with the GaAs quantum wells grown by molecular beam epitaxy at low temperatures remains elusive. The operation of such a platform calls for long-lifetime, strongly interacting excitons in a stringent material system with large yet nanoscale-thin geometry and homogeneous properties. Here, we address this challenge by adopting a method based on the solution synthesis of excitonic halide perovskites grown under nanoconfinement. Such nanoconfinement growth facilitates the synthesis of smooth and homogeneous single-crystalline large crystals enabling the demonstration of XY Hamiltonian lattices with sizes up to 10 × 10. With this demonstration, we further establish perovskites as a promising...

Near-field ultrafast nanoscopy of carrier dynamics in silicon nanowires

Tue, 6 May 2025 00:00:00 +0000

Carrier distribution and dynamics in semiconductor materials often govern their physics properties that are critical to functionalities and performance in industrial applications. The continued miniaturization of electronic and photonic devices calls for new tools to probe carrier behavior in semiconductors simultaneously at the picosecond time and nanometer length scales. Here, we develop pump-probe scattering-type scanning near-field optical microscopy (s-SNOM) to characterize the carrier dynamics in semiconductor nanowires. By coupling experiments with the point-dipole model, we resolve the size-dependent photoexcited carrier lifetime in individual silicon nanowires. We further demonstrate local carrier decay time mapping in silicon nanostructures with a sub-50 nm spatial resolution. Our pump-probe s-SNOM enables the nanoimaging of ultrafast carrier kinetics, which is an important step in advancing the future design of a broad range of electronic, photonic, and optoelectronic...

Pre-training on Synthetic Driving Data for Trajectory Prediction

Wed, 9 Apr 2025 00:00:00 +0000

Accumulating substantial volumes of real-world driving data proves pivotal in the realm of trajectory forecasting for autonomous driving. Given the heavy reliance of current trajectory forecasting models on data-driven methodologies, we aim to tackle the challenge of learning general trajectory forecasting representations under limited data availability. We propose a pipeline-level solution to mitigate the issue of data scarcity in trajectory forecasting. The solution is composed of two parts: firstly, we adopt HD map augmentation and trajectory synthesis for generating driving data, and then we learn representations by pre-training on them. Specifically, we apply vector transformations to reshape the maps, and then employ a rule-based model to generate trajectories on both original and augmented scenes; thus enlarging the driving data without collecting additional real ones. To foster the learning of general representations within this augmented dataset, we comprehensively explore...

The Nusselt number of a hot sphere levitated by a volatile pool

Tue, 8 Apr 2025 00:00:00 +0000

When placed at the surface of a volatile liquid, a sphere of hot dense non-volatile material remains suspended until it cools sufficiently. The duration of this ‘inverse Leidenfrost’ phenomenon depends on the Nusselt number $Nu$ of the sphere, itself determined by flow in the film of vapour separating particle and liquid. It is shown that provided the Nusselt number is large, it can be calculated numerically using only the Laplace relation and the equations governing the thin film; patching to a solution for the outer thick film is not necessary. This method is demonstrated by using it to determine $Nu$ for a sphere sufficiently small that in the governing equations, the acceleration due to gravity is negligible except where multiplied by the density of the sphere. Numerical results giving $Nu$ as a function of a dimensionless measure of sphere weight are supplemented with analysis showing that,...

Untethered subcentimeter flying robots

Mon, 7 Apr 2025 00:00:00 +0000

The miniaturization of insect-scale flying robots with untethered flights is extremely challenging as the tradeoff between mass and power becomes problematic. Here, a subcentimeter rotating-wing robot of 21 mg in weight and 9.4 mm in wingspan driven by a single-axis alternating magnetic field has accomplished navigable flights. This artificial flying robot is the lightest and smallest to realize untethered and controllable aerial travels including hovering, collision recovery, and route adjustments. Experimentally, it has achieved a high aerodynamic efficacy with a measured lift-to-drag ratio of 0.7 and lift-to-flying power ratio of 7.2 × 10^-2 N/W at a Reynolds number of ~2500. The wireless driving mechanism, system operation principle, and flight characteristics can be further optimized for the advancement and miniaturization of subcentimeter scale flying robots.

Thermoelectric porous laser-induced graphene-based strain-temperature decoupling and self-powered sensing

Thu, 3 Apr 2025 00:00:00 +0000

Despite rapid developments of wearable self-powered sensors, it is still elusive to decouple the simultaneously applied multiple input signals. Herein, we report the design and demonstration of stretchable thermoelectric porous graphene foam-based materials via facile laser scribing for self-powered decoupled strain and temperature sensing. The resulting sensor can accurately detect temperature with a resolution of 0.5°C and strain with a gauge factor of 1401.5. The design of the nanocomposites also explores the synergistic effect between the porous graphene and thermoelectric components to greatly enhance the Seebeck coefficient by almost four times (from 9.703 to 37.33 μV/°C). Combined with the stretchability of 45%, the self-powered sensor platform allows for early fire detection in remote settings and accurate and decoupled monitoring of temperature and strain during the wound healing process in situ. The design concepts from this study could also be leveraged to prepare multimodal...

Pulsed field ablation in medicine: irreversible electroporation and electropermeabilization theory and applications

Thu, 3 Apr 2025 00:00:00 +0000

BACKGROUND: Focal ablation techniques are integral in the surgical intervention of diseased tissue, where it is necessary to minimize damage to the surrounding parenchyma and critical structures. Irreversible electroporation (IRE) and high-frequency IRE (H-FIRE), colloquially called pulsed-field ablation (PFA), utilize high-amplitude, low-energy pulsed electric fields (PEFs) to nonthermally ablate soft tissue. PEFs induce cell death through permeabilization of the cellular membrane, leading to loss of homeostasis. The unique nonthermal nature of PFA allows for selective cell death while minimally affecting surrounding proteinaceous structures, permitting treatment near sensitive anatomy where thermal ablation or surgical resection is contraindicated. Further, PFA is being used to treat tissue when tumor margins are not expected after surgical resection, termed margin accentuation. This review explores both the theoretical foundations of PFA, detailing how PEFs induce cell membrane...

A size-dependent ideal solution model for liquid–solid phase equilibria prediction in aqueous organic solutions

Thu, 3 Apr 2025 00:00:00 +0000

Predictive synthesis of aqueous organic solutions with desired liquid-solid phase equilibria could drive progress in industrial chemistry, cryopreservation, and beyond, but is limited by the predictive power of current solution thermodynamics models. In particular, few analytical models enable accurate liquidus and eutectic prediction based only on bulk thermodynamic properties of the pure components, requiring instead either direct measurement or costly simulation of solution properties. In this work, we demonstrate that a simple modification to the canonical ideal solution theory accounting for the entropic effects of dissimilar molecule sizes can transform its predictive power. Incorporating a Flory-style entropy of mixing term that includes both the mole and volume fractions of each component, we derive size-dependent equations for the ideal chemical potential and liquidus temperature, and use them to predict the binary phase diagrams of water and 10 organic solutes of varying...

Vascular Microphysiological System for Investigating Endothelial Barrier Function During Organ Preservation and Reperfusion

Wed, 2 Apr 2025 00:00:00 +0000

Endothelial cell damage after cold preservation and reperfusion injury causes deterioration of the endothelial barrier and ultimately results in edema, leading to transplant failure. Here, a vascular microphysiological system (MPS) is introduced as a testbed to investigate the combinational effect of thermal and fluid perturbations (i.e., wall shear stress) on human endothelial barrier function. Two methods of organ storage are compared: isochoric supercooling (ISC) preservation, which prevents ice formation at subzero temperatures; and, the standard clinical protocol of static cold storage (SCS) at 4 °C. Integrating electrical impedance measurements on chip allow real-time monitoring and quantification of barrier function during preservation and reperfusion protocols. Isochoric supercooling preservation enables longer periods of preservation with superior recovery of barrier function during reperfusion, and has lower metabolic activities compared to static cold storage. Genomic...

Multi‐Zone Visco‐Node‐Pore Sensing: A Microfluidic Platform for Multi‐Frequency Viscoelastic Phenotyping of Single Cells

Tue, 1 Apr 2025 00:00:00 +0000

This study introduces multi-zone visco-Node-Pore Sensing (mz-visco-NPS), an electronic-based microfluidic platform for single-cell viscoelastic phenotyping. mz-visco-NPS implements a series of sinusoidal-shaped contraction zones that periodically deform a cell at specific strain frequencies, leading to changes in resistance across the zones that correspond to the cell's frequency-dependent elastic G' and viscous G″ moduli. mz-visco-NPS is validated by measuring the viscoelastic changes of MCF-7 cells when their cytoskeleton is disrupted. mz-visco-NPS is also employed to measure the viscoelastic properties of human mammary epithelial cells across the entire continuum of epithelial transformation states, from average- and high-risk primary epithelial cells, to immortal non-malignant (MCF-10A), malignant (MCF-7), and metastatic (MDA-MB-231) cell lines. With a throughput of 600 cells per hour and demonstrated ease-of-use, mz-visco-NPS reveals a remarkable level of single-cell heterogeneity...

Biomimetic 3D Prototyping of Hierarchically Porous Multilayered Membranes for Enhanced Oil–Water Filtration

Tue, 1 Apr 2025 00:00:00 +0000

This study introduces a biomimetic approach to 3D printing multilayered hierarchical porous membranes (MHMs) using Direct Ink Writing (DIW) technology. Fabricated through a fast layer-by-layer printing process with varying concentrations of pore-forming agents, the produced MHMs mimic the hierarchical pore structure and filtration capabilities of natural soil systems. As a result, the 3D-printed MHMs achieved an impressive oil rejection rate of 99.02% and demonstrated exceptional reusability, maintaining a flux recovery ratio of 99.48% even after hours of continuous filtration. Moreover, the 3D-printed MHMs exhibit superior hierarchical porous architecture and mechanical integrity compared to traditional flat sheet single-layered membranes. This study presents a significant advancement for scalable 3D printing of customized multilayer membranes with tailored porosity and high-performance filtration properties. The simplicity, versatility, and cost-effectiveness of the presented...

Artificial intelligence in musculoskeletal applications: a primer for radiologists

Mon, 24 Mar 2025 00:00:00 +0000

As an umbrella term, artificial intelligence (AI) covers machine learning and deep learning. This review aimed to elaborate on these terms to act as a primer for radiologists to learn more about the algorithms commonly used in musculoskeletal radiology. It also aimed to familiarize them with the common practices and issues in the use of AI in this domain.

Artificial intelligence driven laser parameter search: Inverse design of photonic surfaces using greedy surrogate-based optimization

Fri, 7 Mar 2025 00:00:00 +0000

Photonic surfaces designed with specific optical characteristics are becoming increasingly crucial for novel energy harvesting and storage systems. The design of these surfaces can be achieved by texturing materials using lasers. The optimal adjustment of laser fabrication parameters to achieve target surface optical properties is an open challenge. Thus, we develop a surrogate-based optimization approach. Our framework employs the Random Forest algorithm to model the forward relationship between the laser fabrication parameters and the resulting optical characteristics. During the optimization process, we use a greedy, prediction-based exploration strategy that iteratively selects batches of laser parameters to be used in experimentation by minimizing the predicted discrepancy between the surrogate model’s outputs and the user-defined target optical characteristics. This strategy allows for efficient identification of optimal fabrication parameters without the need to model the...

Inverse design of photonic surfaces via multi fidelity ensemble framework and femtosecond laser processing

Thu, 6 Mar 2025 00:00:00 +0000

We demonstrate a multi-fidelity (MF) machine learning ensemble framework for the inverse design of photonic surfaces, trained on a dataset of 11,759 samples that we fabricate using high throughput femtosecond laser processing. The MF ensemble combines an initial low fidelity model for generating design solutions, with a high fidelity model that refines these solutions through local optimization. The combined MF ensemble can generate multiple disparate sets of laser-processing parameters that can each produce the same target input spectral emissivity with high accuracy (root mean squared errors < 2%). SHapley Additive exPlanations analysis shows transparent model interpretability of the complex relationship between laser parameters and spectral emissivity. Finally, the MF ensemble is experimentally validated by fabricating and evaluating photonic surface designs that it generates for improved efficiency energy harvesting devices. Our approach provides a powerful tool for advancing...

Application of Isochoric Impregnation: Effects on Microbial and Physicochemical Parameters and Shelf Life of Strawberries Stored Under Refrigeration

Mon, 3 Mar 2025 00:00:00 +0000

This study evaluates the effectiveness of isochoric impregnation during isochoric cold storage in extending the shelf life of strawberries. Strawberries in two different impregnation solutions-(1) sucrose solution and (2) sucrose solution containing calcium chloride (CaCl₂) and ascorbic acid (AA)-were first stored in an isochoric chamber at -2 °C/48 MPa for 1 week, followed by refrigeration at 4 °C for 3 weeks. For comparison, strawberries were also immersed in each solution for 1 week at 4 °C then refrigerated at 4 °C for 3 weeks. Additionally, a control group of fresh strawberries was stored at 4 °C for 4 weeks. The quality of the strawberries was assessed at 1-week intervals throughout the storage period. Isochoric cold storage effectively inhibited microbial growth and reduced the weight loss of the strawberries compared to refrigerated storage. Also, isochoric cold storage resulted in strawberries that retained their color attributes, whereas refrigeration led...

Optical Emission Spectroscopy and Gas Kinetics of Picosecond Laser-Induced Chlorine Dissociation for Atomic Layer Etching of Silicon

Thu, 27 Feb 2025 00:00:00 +0000

The continuing developments in semiconductor device technologies have prompted the need for advanced nanoscale processing techniques. Laser chemical processing offers significant advantages, including spatial selectivity, high localization, minimal material damage, and fast operation. Pulsed laser-induced dissociation of gas species serves as an essential process step, contributing to doping, etching, and other chemical modifications of semiconductor materials. However, the mechanisms behind the laser-gas interactions and subsequent surface modifications remain elusive. Here, we demonstrate ultraviolet picosecond laser-induced atomic layer etching of silicon in a gaseous chlorine environment, achieving self-limited etching with a precision of 0.93 nm/cycle. Through in situ optical emission spectroscopy, we elucidate the transition energy states of laser-excited products during chlorination. Complementing our experimental findings, we perform numerical modeling that reveals...

System-level modeling with temperature compensation for a CMOS-MEMS monolithic calorimetric flow sensing SoC

Thu, 27 Feb 2025 00:00:00 +0000

We present a system-level model with an on-chip temperature compensation technique for a CMOS-MEMS monolithic calorimetric flow sensing SoC. The model encompasses mechanical, thermal, and electrical domains to facilitate the co-design of a MEMS sensor and CMOS interface circuits on the EDA platform. The compensation strategy is implemented on-chip with a variable temperature difference heating circuit. Results show that the linear programming for the low-temperature drift in the SoC output is characterized by a compensation resistor Rc with a resistance value of 748.21 Ω and a temperature coefficient of resistance of 3.037 × 10−3 °C−1 at 25 °C. Experimental validation demonstrates that within an ambient temperature range of 0–50 °C and a flow range of 0–10 m/s, the temperature drift of the sensor is reduced to ±1.6%, as compared to ±8.9% observed in a counterpart with the constant temperature difference circuit. Therefore, this on-chip temperature-compensated CMOS-MEMS flow sensing...

Decoupling Carrier Dynamics and Energy Transport in Ultrafast Near-Field Nanoscopy

Thu, 27 Feb 2025 00:00:00 +0000

Ultrafast near-field optical nanoscopy has emerged as a powerful platform to characterize low-dimensional materials. While analytical and numerical models have been established to account for photoexcited carrier dynamics, quantitative evaluation of the associated pulsed laser heating remains elusive. Here, we decouple the photocarrier density and temperature increase in near-field nanoscopy by integrating the two-temperature model (TTM) with finite-difference time-domain (FDTD) simulations. These results reveal that the electron-phonon coupling in a silicon film after femtosecond laser excitation is most pronounced within approximately 3 ps─substantially shorter than the photocarrier decay time scale at tens of picoseconds. Moreover, the coupled TTM-FDTD method indicates that ultrafast laser heating can cause up to a 14% variation in the near-field signal at a 220 μJ/cm² pump pulse fluence. Our numerical results are further validated by transient experiments, highlighting...

SeqSeg: Learning Local Segments for Automatic Vascular Model Construction

Mon, 17 Feb 2025 00:00:00 +0000

Computational modeling of cardiovascular function has become a critical part of diagnosing, treating and understanding cardiovascular disease. Most strategies involve constructing anatomically accurate computer models of cardiovascular structures, which is a multistep, time-consuming process. To improve the model generation process, we herein present SeqSeg (sequential segmentation): a novel deep learning-based automatic tracing and segmentation algorithm for constructing image-based vascular models. SeqSeg leverages local U-Net-based inference to sequentially segment vascular structures from medical image volumes. We tested SeqSeg on CT and MR images of aortic and aortofemoral models and compared the predictions to those of benchmark 2D and 3D global nnU-Net models, which have previously shown excellent accuracy for medical image segmentation. We demonstrate that SeqSeg is able to segment more complete vasculature and is able to generalize to vascular structures not annotated...

Inpatient autopsy rate and associated factors in a Chinese megacity: a population-based retrospective cohort study

Fri, 14 Feb 2025 00:00:00 +0000

OBJECTIVES: This study investigated the autopsy rate of hospital deaths in Shenzhen megacity and identified factors that may impact the decision to perform an autopsy in hospital deaths. DESIGN: This is a population-based retrospective cohort study. SETTING: Shenzhen is a megacity in China with a population of more than 17 million and a total of 151 hospitals. The official dataset of the inpatient medical record home page was used. Demographic, clinical and hospital information was extracted. PARTICIPANTS: All the 35 272 inpatient deaths between 2016 and 2022 with known autopsy status were included to calculate the overall autopsy rate. Among them, a total of 34 577 cases with complete data, classified hospital and Chinese nationality, were included for further multivariable rare events logistic regression and Poisson pseudo maximum likelihood regression. OUTCOME MEASURES: Whether the inpatient death was autopsied or not. RESULTS: The autopsy procedure was performed in 0.9% (319/35...

A compliant metastructure design with reconfigurability up to six degrees of freedom

Fri, 14 Feb 2025 00:00:00 +0000

Compliant mechanisms with reconfigurable degrees of freedom are gaining attention in the development of kinesthetic haptic devices, robotic systems, and mechanical metamaterials. However, available devices exhibit limited programmability and form-customizability, restricting their versatility. To address this gap, we propose a metastructure concept featuring reconfigurable motional freedom and tunable stiffness, adaptable to various form factors and applications. These devices incorporate passive flexures and actively stiffness-changing rods to modify kinematic freedom. A rational design pipeline informs the flexures’ topological arrangements, geometric parameters, and control signals based on targeted mobilities, enabling the creation of unitary joints with up to six degrees of freedom. Our demonstrative application examples include a wrist device that has an effective stiffness of 0.370 Nm/deg (unlocked state, 5% displacement) to 2.278 Nm/deg (locked state, 1% displacement)...

Synchronous and Fully Steerable Active Particle Systems for Enhanced Mimicking of Collective Motion in Nature

Thu, 13 Feb 2025 00:00:00 +0000

The collective motion observed in living active matter, such as fish schools and bird flocks, is characterized by its dynamic and complex nature, involving various moving states and transitions. By tailoring physical interactions or incorporating information exchange capabilities, inanimate active particles can exhibit similar behavior. However, the lack of synchronous and arbitrary control over individual particles hinders their use as a test system for the study of more intricate collective motions in living species. Herein, a novel optical feedback control system that enables the mimicry of collective motion observed in living objects using active particles is proposed. This system allows for the experimental investigation of the velocity alignment, a seminal model of collective motion (known as the Vicsek model), in a microscale perturbed environment with controllable and realistic conditions. The spontaneous formation of different moving states and dynamic transitions between...

Absorbing boundary conditions in material point method adopting perfectly matched layer theory

Tue, 4 Feb 2025 00:00:00 +0000

This study focuses on solving the numerical challenges of imposing absorbing boundary conditions for dynamic simulations in the material point method (MPM). To attenuate elastic waves leaving the computational domain, the current work integrates the Perfectly Matched Layer (PML) theory into the implicit MPM framework. The proposed approach introduces absorbing particles surrounding the computational domain that efficiently absorb outgoing waves and reduce reflections, allowing for accurate modeling of wave propagation and its further impact on geotechnical slope stability analysis. The study also includes several benchmark tests to validate the effectiveness of the proposed method, such as several types of impulse loading and symmetric and asymmetric base shaking. The conducted numerical tests also demonstrate the ability to handle large deformation problems, including the failure of elasto-plastic soils under gravity and dynamic excitations. The findings extend the capability...

Self-Heating Conductive Ceramic Composites for High Temperature Thermal Energy Storage

Mon, 3 Feb 2025 00:00:00 +0000

The absence of affordable and deployable large-scale energy storage poses a major barrier to providing zero-emission energy on demand for societal decarbonization. High temperature thermal energy storage is one promising option with low cost and high scalability, but it is hindered by the inherent complexity of simultaneously satisfying all of the material requirements. Here we design a class of ceramic–carbon composites based on co-optimizing mechanical, electrical, and thermal properties. These composites demonstrate stability in soak-and-hold tests and direct self-heating up to 1,936 °C and 750 thermal cycles from 500 to 1,630 °C without degradation. This thermal performance derives from their composition and microstructural design as verified by in situ high-temperature transmission electron microscopy and X-ray diffraction. They offer both higher energy density and lower cost than conventional storage technologies with a projected system Levelized Cost of Storage below the...

A tunable metamaterial microwave absorber inspired by chameleon’s color-changing mechanism

Sat, 1 Feb 2025 00:00:00 +0000

A metamaterial absorber capable of swiftly altering its electromagnetic response in the microwave range offers adaptability to changing environments, such as tunable stealth capabilities. Inspired by the chameleon's ability to change color through the structural transformation of photonic lattice crystals, which shift the bandgaps of reflection and transmission of visible light, we designed a crisscross structure that transforms from an expanded to a collapsed form. This transformation enables a switch between broadband absorption and peak transmission in the microwave range (4 to 18 gigahertz). The structure, optimized through data-driven design, is mechanically actuated by the rotation of interlinked trusses. This mechanism changes the entire array's response, allowing it to remain undetected by an external radar or to transmit an internal radar signal to a near-field receiver when needed. The mechanical actuation and the shifting electromagnetic response of the arrayed structure...

Multiphoton and Harmonic Imaging of Microarchitected Materials

Thu, 30 Jan 2025 00:00:00 +0000

Microadditive manufacturing has revolutionized the production of complex, nano- to microscale components across various fields. This work investigates two-photon (2P) and three-photon (3P) fluorescence imaging, as well as third-harmonic generation (THG) microscopy, to examine periodic microarchitected lattice structures fabricated using multiphoton lithography (MPL). By immersing the structures in refractive index matching fluids, we demonstrate high-fidelity 3D reconstructions of both fluorescent structures using 2P and 3P microscopy as well as low-fluorescence structures using THG microscopy. These results show that multiphoton fluorescence (MPF) imaging offers reduced signal decay with respect to depth compared to single-photon techniques in the examined structures. We further demonstrate the ability to nondestructively identify intentional internal modifications of the structure that are not immediately visible with scanning electron microscope (SEM) images and compression-induced...

Development of a self-powered digital LAMP microfluidic chip (SP-dChip) for the detection of emerging viruses

Fri, 24 Jan 2025 00:00:00 +0000

Point-of-care (POC) diagnostics have emerged as a crucial technology for emerging pathogen detections to enable rapid and on-site detection of infectious diseases. However, current POC devices often suffer from limited sensitivity with poor reliability to provide quantitative readouts. In this paper, we present a self-powered digital loop-mediated isothermal amplification (dLAMP) microfluidic chip (SP-dChip) for the rapid and quantitative detection of nucleic acids. The SP-dChip utilizes a vacuum lung design to passively digitize samples into individual nanoliter wells for high-throughput analysis. The superior digitization scheme is further combined with reverse transcription loop-mediated isothermal amplification (RT-LAMP) to demonstrate dLAMP detection of Zika virus (ZIKV). Firstly, the LAMP assay is loaded into the chip and passively digitized into individual wells. Mineral oil is then pipetted through the chip to differentiate each well as an individual reactor. The chip...

Automated Gold Nanorod Spectral Morphology Analysis Pipeline

Tue, 7 Jan 2025 00:00:00 +0000

The development of a colloidal synthesis procedure to produce nanomaterials with high shape and size purity is often a time-consuming, iterative process. This is often due to quantitative uncertainties in the required reaction conditions and the time, resources, and expertise intensive characterization methods required for quantitative determination of nanomaterial size and shape. Absorption spectroscopy is often the easiest method for colloidal nanomaterial characterization. However, due to the lack of a reliable method to extract nanoparticle shapes from absorption spectroscopy, it is generally treated as a more qualitative measure for metal nanoparticles. This work demonstrates a gold nanorod (AuNR) spectral morphology analysis tool, called AuNR-SMA, which is a fast and accurate method to extract quantitative structural information from colloidal AuNR absorption spectra. To demonstrate the practical utility of this model, we apply it to three distinct applications. First, we...

High sound pressure piezoelectric micromachined ultrasonic transducers using sputtered potassium sodium niobate

Thu, 2 Jan 2025 00:00:00 +0000

This work presents air-coupled piezoelectric micromachined ultrasonic transducers (pMUTs) with high sound pressure level (SPL) under low-driving voltages by utilizing sputtered potassium sodium niobate K0.34Na0.66NbO3 (KNN) films. A prototype single KNN pMUT has been tested to show a resonant frequency at 106.3 kHz under 4 Vp-p with outstanding characteristics: (1) a large vibration amplitude of 3.74 μm/V, and (2) a high acoustic root mean square (RMS) sound pressure level of 105.5 dB/V at 10 cm, which is 5–10 times higher than those of AlN-based pMUTs at a similar frequency. There are various potential sensing and actuating applications, such as fingerprint sensing, touch point, and gesture recognition. In this work, we present demonstrations in three fields: haptics, loudspeakers, and rangefinders. For haptics, an array of 15 × 15 KNN pMUTs is used as a non-contact actuator to provide a focal pressure of around 160.3 dB RMS SPL at a distance of 15 mm. This represents the highest...

Integrin mechanosensing relies on a pivot-clip mechanism to reinforce cell adhesion

Tue, 24 Dec 2024 00:00:00 +0000

Cells intricately sense mechanical forces from their surroundings, driving biophysical and biochemical activities. This mechanosensing phenomenon occurs at the cell-matrix interface, where mechanical forces resulting from cellular motion, such as migration or matrix stretching, are exchanged through surface receptors, primarily integrins, and their corresponding matrix ligands. A pivotal player in this interaction is the α₅β₁ integrin and fibronectin (FN) bond, known for its role in establishing cell adhesion sites for migration. However, upregulation of the α₅β₁-FN bond is associated with uncontrolled cell metastasis. This bond operates through catch bond dynamics, wherein the bond lifetime paradoxically increases with greater force. The mechanism sustaining the characteristic catch bond dynamics of α₅β₁-FN remains unclear. Leveraging molecular dynamics simulations, our approach unveils a pivot-clip mechanism....

Low-loss, geometry-invariant optical waveguides with near-zero-index materials

Fri, 20 Dec 2024 00:00:00 +0000

Optical materials with nearly zero refractive indices have driven emerging applications ranging from geometry-invariant optical tunneling, nonlinear optics, optical cloaking to thermal emission manipulation. In conventional dielectric photonic circuits, light scattering and back reflection at the waveguide bends and crossings leads to significant optical loss. Here we propose to use near-zero-index materials as a cladding layer for low-loss optical waveguides, where optical modes are tightly confined within the dielectric core region. Compared to conventional waveguides, the near-zero-index waveguides are superior in maintaining a high mode-filling factor for small device sizes close to the diffraction limit and reducing the crosstalk in between at a sub-wavelength separation. In addition, we found that light propagation is robust to waveguide bends in a small radius (∼µm) and geometry variation in the cross section. Hollow waveguides with near-zero-index cladding layers further...

Nanostructured Surfaces Enhance Nucleation Rate of Calcium Carbonate

Fri, 6 Dec 2024 00:00:00 +0000

Nucleation and growth of calcium carbonate on surfaces is of broad importance in nature and technology, being essential to the calcification of organisms, while negatively impacting energy conversion through crystallization fouling, also called scale formation. Previous work studied how confinements, surface energies, and functionalizations affect nucleation and polymorph formation, with surface-water interactions and ion mobility playing important roles. However, the influence of surface nanostructures with nanocurvature-through pit and bump morphologies-on scale formation is unknown, limiting the development of scalephobic surfaces. Here, it is shown that nanoengineered surfaces enhance the nucleation rate by orders of magnitude, despite expected inhibition through effects like induced lattice strain through surface nanocurvature. Interfacial and holographic microscopy is used to quantify crystallite growth and find that nanoengineered interfaces experience slower individual...

Pricing for multi-modal pickup and delivery problems with heterogeneous users

Wed, 20 Nov 2024 00:00:00 +0000

Pricing for multi-modal pickup and delivery problems with heterogeneous users

Stretchable Triboelectric Nanogenerator Based on Liquid Metal with Varying Phases

Fri, 8 Nov 2024 00:00:00 +0000

Stretchable triboelectric nanogenerators (TENGs) represent a new class of energy-harvesting devices for powering wearable devices. However, most of them are associated with poor stretchability, low stability, and limited substrate material choices. This work presents the design and demonstration of highly stretchable and stable TENGs based on liquid metalel ectrodes with different phases. The conductive and fluidic properties of eutectic gallium-indium (EGaIn) in the serpentine microfluidic channel ensure the robust performance of the EGaIn-based TENG upon stretching over several hundred percent. The bi-phasic EGaIn (bGaIn) from oxidation lowers surface tension and increases adhesion for printing on diverse substrates with high output performance parameters. The optimization of the electrode shapes in the bGaIn-based TENGs can reduce the device footprint and weight, while enhancing stretchability. The applications of the EGaIn- and bGaIn-based TENG include smart elastic bands...

Multi‐Objective Bayesian Optimization for Laminate‐Inspired Mechanically Reinforced Piezoelectric Self‐Powered Sensing Yarns

Thu, 7 Nov 2024 00:00:00 +0000

Piezoelectric fiber yarns produced by electrospinning offer a versatile platform for intelligent devices, demonstrating mechanical durability and the ability to convert mechanical strain into electric signals. While conventional methods involve twisting a single poly(vinylidene fluoride-co-trifluoroethylene)(P(VDF-TrFE)) fiber mat to create yarns, by limiting control over the mechanical properties, an approach inspired by composite laminate design principles is proposed for strengthening. By stacking multiple electrospun mats in various sequences and twisting them into yarns, the mechanical properties of P(VDF-TrFE) yarn structures are efficiently optimized. By leveraging a multi-objective Bayesian optimization-based machine learning algorithm without imposing specific stacking restrictions, an optimal stacking sequence is determined that simultaneously enhances the ultimate tensile strength (UTS) and failure strain by considering the orientation angles of each aligned fiber mat...

Data-driven airfoil shape optimization framework for enhanced flutter performance

Wed, 6 Nov 2024 00:00:00 +0000

This paper presents a machine learning-based airfoil shape optimization framework designed to increase flutter resistance and reduce drag. Using the National Advisory Committee for Aeronautics airfoil as the base design and a Hicks–Henne bump function, we employ multi-objective Bayesian optimization and harmonic balance-based flutter prediction. The optimization process yields a Pareto front revealing trade-off relationships between the flutter speed index and drag coefficient. The optimized airfoils, resembling those of evolved marine animals, outperform the base design in terms of flutter resistance and drag. These results demonstrate the framework's potential to enhance aircraft performance and safety by addressing aeroelastic factors.

Nitrogen accountancy in space agriculture

Wed, 30 Oct 2024 00:00:00 +0000

Food production and pharmaceutical synthesis are posited as essential biotechnologies for facilitating human exploration beyond Earth. These technologies not only offer critical green space and food agency to astronauts but also promise to minimize mass and volume requirements through scalable, modular agriculture within closed-loop systems, offering an advantage over traditional bring-along strategies. Despite these benefits, the prevalent model for evaluating such systems exhibits significant limitations. It lacks comprehensive inventory and mass balance analyses for crop cultivation and life support, and fails to consider the complexities introduced by cultivating multiple crop varieties, which is crucial for enhancing food diversity and nutritional value. Here we expand space agriculture modeling to account for nitrogen dependence across an array of crops and demonstrate our model with experimental fitting of parameters. By adding nitrogen limitations, an extended model can...

High-throughput homogenization of a quasi-Gaussian ultrafast laser beam using a combined refractive beam shaper and spatial light modulator

Tue, 22 Oct 2024 00:00:00 +0000

Efficiently shaping femtosecond, transverse Gaussian laser beams to flat-top beams with flat wavefronts is critical for large-scale material processing and manufacturing. Existing beam shaping devices fall short either in final beam homogeneity or efficiency. We present an approach that uses refractive optics to perform the majority of the beam shaping and then uses a fine-tune device (spatial light modulator) to refine the intensity profile. For the beam that we selected, circularly asymmetric with intensity fluctuations, our method achieved a uniformity of 0.055 within 90% of the beam area at 92% efficiency. The optimization involved an iterative beam shaping process that converged to optimum within 10 iterations.

Establishment and validation of a predictive nomogram for gestational diabetes mellitus during early pregnancy term: A retrospective study

Fri, 11 Oct 2024 00:00:00 +0000

Objective: This study aims to develop and evaluate a predictive nomogram for early assessment risk factors of gestational diabetes mellitus (GDM) during early pregnancy term, so as to help early clinical management and intervention. Methods: A total of 824 pregnant women at Zhongnan Hospital of Wuhan University and Maternal and Child Health Hospital of Hubei Province from 1 February 2020 to 30 April 2020 were enrolled in a retrospective observational study and comprised the training dataset. Routine clinical and laboratory information was collected; we applied least absolute shrinkage and selection operator (LASSO) logistic regression and multivariate ROC risk analysis to determine significant predictors and establish the nomogram, and the early pregnancy files (gestational weeks 12-16, n = 392) at the same hospital were collected as a validation dataset. We evaluated the nomogram via the receiver operating characteristic (ROC) curve, C-index, calibration curve,...

Effects of Crumpling Stage and Porosity of Graphene Electrode on the Performance of Electrochemical Supercapacitor

Thu, 10 Oct 2024 00:00:00 +0000

The performance characteristics of supercapacitors composed of crumpled graphene electrodes and aqueous NaCl electrolytes are investigated through Molecular Dynamics (MD) simulations using a newly developed crumpled graphene-based supercapacitor model. Results suggest that the three-dimensional configuration of crumpled graphene boosts electrolyte-electrode interaction. This improved interaction, which includes a larger ion-accessible zone, increases the specific capacitance of the supercapacitor by roughly 400% (16.4 μF/cm²) compared to planar graphene electrodes. Examining the effect of different stages of crumpling and the inclusion of pores on the electrode surface shows that the stages of crumpling substantially influence the supercapacitor performance. A smaller crumpling radius, meaning fully crumpled stage, improves the performance as increased crumpling leads to better packing efficiency, which aids in more ion separation. Furthermore, adding pores on the surface...

Superhydrophobic, stretchable kirigami pencil-on-paper multifunctional device platform

Thu, 19 Sep 2024 00:00:00 +0000

Wearable electronics with applications in healthcare, human-machine interfaces, and robotics often explore complex manufacturing procedures and are not disposable. Although the use of conductive pencil patterns on cellulose paper provides inexpensive, disposable sensors, they have limited stretchability and are easily affected by variations in the ambient environment. This work presents the combination of pencil-on-paper with the hydrophobic fumed SiO₂ (Hf-SiO₂) coating and stretchable kirigami structures from laser cutting to prepare a superhydrophobic, stretchable pencil-on-paper multifunctional sensing platform. The resulting sensor exhibits a large response to NO₂ gas at elevated temperature from self-heating, which is minimally affected by the variations in the ambient temperature and relative humidity, as well as mechanical deformations such as bending and stretching states. The integrated temperature sensor and electrodes with the sensing...

Enhancing the electric charge output in LiNbO 3 -based piezoelectric pressure sensors

Thu, 19 Sep 2024 00:00:00 +0000

Lithium niobate (LiNbO₃) single crystals are a kind of ferroelectric material with a high piezoelectric coefficient and Curie temperature, which is suitable for the preparation of piezoelectric pressure sensors. However, there is little research reporting on the use of LiNbO₃ single crystals to prepare piezoelectric pressure sensors. Therefore, in this paper, LiNbO₃ was used to prepare piezoelectric pressure sensors to study the feasibility of using LiNbO₃ single crystals as a sensitive material for piezoelectric pressure sensors. In addition, chemical mechanical polishing (CMP) technology was used to prepare LiNbO₃ crystals with different thicknesses to study the influence of these LiNbO₃ crystals on the electric charge output of the sensors. The results showed that the sensitivity of a 300 μm sample (0.218 mV kPa^-1) was about 1.23 times that of a 500 μm sample (0.160 mV kPa^-1). Low-temperature...

Self‐Healing, Reconfigurable, Thermal‐Switching, Transformative Electronics for Health Monitoring

Thu, 19 Sep 2024 00:00:00 +0000

Soft, deformable electronic devices provide the means to monitor physiological information and health conditions for disease diagnostics. However, their practical utility is limited due to the lack of intrinsical thermal switching for mechanically transformative adaptability and self-healing capability against mechanical damages. Here, the design concepts, materials and physics, manufacturing approaches, and application opportunities of self-healing, reconfigurable, thermal-switching device platforms based on hyperbranched polymers and biphasic liquid metal are reported. The former provides excellent self-healing performance and unique tunable stiffness and adhesion regulated by temperature for the on-skin switch, whereas the latter results in liquid metal circuits with extreme stretchability (>900%) and high conductivity (3.40 × 10⁴ S cm^-1 ), as well as simple recycling capability. Triggered by the increased temperature from the skin...

Three-Dimensional Metallic Surface Micropatterning through Tailored Photolithography–Transfer–Plating

Mon, 16 Sep 2024 00:00:00 +0000

Precise micropatterning on three-dimensional (3D) surfaces is desired for a variety of applications, from microelectronics to metamaterials, which can be realized by transfer printing techniques. However, a nontrivial deficiency of this approach is that the transferred microstructures are adsorbed on the target surface with weak adhesion, limiting the applications to external force-free conditions. We propose a scalable "photolithography-transfer-plating" method to pattern stable and durable microstructures on 3D metallic surfaces with precise dimension and location control of the micropatterns. Surface patterning on metallic parts with different metals and isotropic and anisotropic curvatures is showcased. This method can also fabricate hierarchical structures with nanoscale vertical and microscale horizontal dimensions. The plated patterns are stable enough to mold soft materials, and the structure durability is validated by 24 h thermofluidic tests. We demonstrate micropatterned...

Near-Field Nanoimaging of Phases and Carrier Dynamics in Vanadium Dioxide Nanobeams

Mon, 16 Sep 2024 00:00:00 +0000

The stable coexistence of insulating and metallic phases in strained vanadium dioxide (VO₂) has garnered significant research interest due to the intriguing phase transition phenomena. However, the temporal behavior of charge carriers in different phases of VO₂ remains elusive. Herein, we employ near-field optical nanoscopy to capture nanoscale alternating phase domains in bent VO₂ nanobeams. By conducting transient measurements across the different phases, we observed a prolonged carrier recombination lifetime in the metallic phase of VO₂, accompanied by an accelerated diffusion process. Our findings reveal nanoscale carrier dynamics in VO₂ nanobeams, offering insights that can facilitate further investigations into phase-change materials and their potential applications in sensing and microelectromechanical devices.

Isolation and characterization of a Halomonas species for non-axenic growth-associated production of bio-polyesters from sustainable feedstocks

Fri, 30 Aug 2024 00:00:00 +0000

Biodegradable plastics are urgently needed to replace petroleum-derived polymeric materials and prevent their accumulation in the environment. To this end, we isolated and characterized a halophilic and alkaliphilic bacterium from the Great Salt Lake in Utah. The isolate was identified as a Halomonas species and designated "CUBES01." Full-genome sequencing and genomic reconstruction revealed the unique genetic traits and metabolic capabilities of the strain, including the common polyhydroxyalkanoate (PHA) biosynthesis pathway. Fluorescence staining identified intracellular polyester granules that accumulated predominantly during the strain's exponential growth, a feature rarely found among natural PHA producers. CUBES01 was found to metabolize a range of renewable carbon feedstocks, including glucosamine and acetyl-glucosamine, as well as sucrose, glucose, fructose, and further glycerol, propionate, and acetate. Depending on the substrate, the strain accumulated up to ~60%...

Techno-economic and carbon dioxide emission assessment of carbon black production

Tue, 27 Aug 2024 00:00:00 +0000

The over 15 million metric tonnes of carbon black produced annually emit carbon dioxide in the range of 29–79 million metric tonnes each year. With the renaissance of carbon black in many new renewable energy applications as well as the growing transportation sector, where carbon black is used as a rubber reinforcement agent in car tires, the carbon black market is expected to grow by 66% over the next 9 years. As such, it is important to better understand energy intensity and carbon dioxide emissions of carbon black production. In this work, the furnace black process is studied in detail using process models to provide insights into mass and energy balances, economics, and potential pathways for lowering the environmental impact of carbon black production. Current state-of-the-art carbon black facilities typically flare the tail gas of the carbon black reactor. While low in heating value, this tail gas contains considerable amounts of energy and flaring this tail gas leads to...

Feasibility of using diamond-like carbon films in total joint replacements: a review.

Sat, 24 Aug 2024 00:00:00 +0000

Diamond-like Carbon (DLC) has been used as a coating material of choice for a variety of technological applications owing to its favorable bio-tribo-thermo-mechanical characteristics. Here, the possibility of bringing DLC into orthopedic joint implants is examined. With ever increasing number of patients suffering from osteoarthritis as well as with the ingress of the osteoarthritic joints malaise into younger and more active demographics, there is a pressing need to augment the performance and integrity of conventional total joint replacements (TJRs). Contemporary joint replacement devices use metal-on-polymer articulations to restore function to worn, damaged or diseased cartilage. The wear of polymeric components has been addressed using crosslinking and antioxidants; however, in the context of the metallic components, complications pertaining to corrosion and metal ion release inside the body still persist. Through this review article, we explore the use of DLC coatings on...

Deep learning enables accurate soft tissue tendon deformation estimation in vivo via ultrasound imaging

Mon, 19 Aug 2024 00:00:00 +0000

Image-based deformation estimation is an important tool used in a variety of engineering problems, including crack propagation, fracture, and fatigue failure. These tools have been important in biomechanics research where measuring in vitro and in vivo tissue deformations are important for evaluating tissue health and disease progression. However, accurately measuring tissue deformation in vivo is particularly challenging due to limited image signal-to-noise ratio. Therefore, we created a novel deep-learning approach for measuring deformation from a sequence of images collected in vivo called StrainNet. Utilizing a training dataset that incorporates image artifacts, StrainNet was designed to maximize performance in challenging, in vivo settings. Artificially generated image sequences of human flexor tendons undergoing known deformations were used to compare benchmark StrainNet against two conventional image-based strain measurement techniques. StrainNet outperformed the traditional...

Nondestructive Imaging of Manufacturing Defects in Microarchitected Materials

Sat, 17 Aug 2024 00:00:00 +0000

Defects in microarchitected materials exhibit a dual nature, capable of both unlocking innovative functionalities and degrading their performance. Specifically, while intentional defects are strategically introduced to customize and enhance mechanical responses, inadvertent defects stemming from manufacturing errors can disrupt the symmetries and intricate interactions within these materials. In this study, we demonstrate a nondestructive optical imaging technique that can precisely locate defects inside microscale metamaterials, as well as provide detailed insights on the specific type of defect.

Spatially Resolved Quantum Sensing with High-Density Bubble-Printed Nanodiamonds

Thu, 15 Aug 2024 00:00:00 +0000

Nitrogen-vacancy (NV^-) centers in nanodiamonds have emerged as a versatile platform for a wide range of applications, including bioimaging, photonics, and quantum sensing. However, the widespread adoption of nanodiamonds in practical applications has been hindered by the challenges associated with patterning them into high-resolution features with sufficient throughput. In this work, we overcome these limitations by introducing a direct laser-writing bubble printing technique that enables the precise fabrication of two-dimensional nanodiamond patterns. The printed nanodiamonds exhibit a high packing density and strong photoluminescence emission, as well as robust optically detected magnetic resonance (ODMR) signals. We further harness the spatially resolved ODMR of the nanodiamond patterns to demonstrate the mapping of two-dimensional temperature gradients using high frame rate widefield lock-in fluorescence imaging. This capability paves the way for integrating nanodiamond-based...

Flow topology changes with bubbly flow around a circular cylinder

Wed, 14 Aug 2024 00:00:00 +0000

Vortex induced vibration (VIV) experienced during flow past a cylinder can reduce equipment performance and in some cases lead to failure. Previous studies have shown that the injection of bubbles in the flow over a cylinder typically leads to a monotonic increase in shedding frequency with void fraction, however, a satisfactory explanation for this phenomenon has not been proposed. Unexplained scatter in the data exists, including that the increase in shedding frequency is not universal. More research is needed to characterize the influence of bubbles on the wake structure, and subsequent shift in shedding frequency. To this aim, the effect of bubbles on the structure of the wake and VIV was examined over two values of Reynolds number, ReD=100,000 and 160,000. Time-resolved particle image velocimetry (TR-PIV), proper orthogonal decomposition (POD) and spectral proper orthogonal decomposition (SPOD) of the wake structures, vibration of the cylinder, and bubble image velocimetry...

PMUT Array for Mid-Air Thermal Display