Mechanical and Aerospace Engineering

Polycarbonate polyurethane (PCU) resins are widely used in biomedical applications due to their excellent mechanical properties, biocompatibility, and resistance to degradation. The performance of these materials in implantable devices depends on factors such as hardness, molecular weight, and their interactions with cells and tissues. Understanding the relationship between material properties and biological outcomes is essential for optimizing their use in medical devices. In this study, three PCU resins were selected for evaluation as potential polymer implant materials: Chronoflex (CF) 65D, and two Carbothane (CB) samples 95A with different molecular weights. Dynamic mechanical analysis (DMA) revealed that the storage modulus was primarily influenced by the hard domain content, with greater elasticity observed at higher frequencies and lower temperatures. Tensile hysteresis behavior at room temperature was strongly correlated with hardness, with lower hardness samples demonstrating improved strain recovery. Cytotoxicity testing indicated cell viability above 70% for both CF and CB films. Normal Human Lung Fibroblasts (NHLF) grown on CF films exhibited a more homogeneous distribution across the surface, adopting an elongated morphology that conformed closely to the underlying topography. In contrast, cells on CB films tend to aggregate, forming clustered structures. This study demonstrates that the mechanical and biological performance of PCU resins is closely linked to their hardness, molecular weight, and structural composition. The results highlight that a morphology with a higher proportion of hard domains produces a more uniform and favorable environment for cell adhesion and organization.

Hearing loss is a widespread and disabling condition with no current cure, underscoring the urgent need for new therapeutic approaches for treatment and prevention. A recent mitochondrial therapy approach by introducing exogenous mitochondria to the cells has shown promising results in mitigating mitochondria-related disorders. Despite the essential role of mitochondria in hearing, this novel strategy has not yet been tested for the treatment of hearing loss. More importantly, whether cochlear cells take up exogenous mitochondria and its consequence on cell bioenergetics has never been tested before. Here, we showed that exogenous mitochondria from HEI-OC1 auditory cells internalize into a new set of HEI-OC1 cells through co-incubation in a dose-dependent manner without inducing toxicity. We observed that auditory cells that received exogenous mitochondria exhibited increased bioenergetics compared to the controls that received none. Furthermore, we found that mitochondrial transplantation protects cells from oxidative stress and H2O2-induced apoptosis, while partially restoring bioenergetics diminished by H2O2 exposure. These findings support initial evidence for the feasibility and potential advantages of mitochondrial therapy in auditory cells. If successful in animal models and ultimately in humans, this novel therapy offers prominent potential for the treatment of sensorineural hearing loss.

This paper presents the design methodology for integrating a hydrogen solid oxide fuel cell/gas turbine (SOFC/GT) propulsion system into a blended-wing–body (BWB) aircraft and tube-and-wing (T&W) configurations for 365 and 162 passengers. The design methodology utilizes aircraft sizing and modeling tools that encompass aerodynamic properties, structural design, and powertrain integration. The proposed hydrogen BWB and T&W aircraft are compared against conventional models like the B777-300ER and B737-800. Key results indicate significant reductions in fuel consumption and emissions. For instance, the hydrogen BWB aircraft, on average, exhibits a 56% reduction in Megajoule of fuel energy consumption per passenger-kilometer compared to conventional aircraft. The analysis highlights the environmental benefits, with [Formula: see text] equivalent emissions per passenger-kilometer being significantly lower for hydrogen-powered models. The total takeoff weight per passenger for the hydrogen BWB-365 is 714 kg, compared to 916 kg for the conventional B777-300ER. Hydrogen aircraft configurations, on average, also show a 21% increase and 99.48% decrease in [Formula: see text] and [Formula: see text] emissions. Moreover, hydrogen BWB configurations exhibit reduced emissions compared to hydrogen T&W despite higher takeoff weights. This study underscores the potential of hydrogen SOFC/GT systems and BWB configurations to enhance efficiency and reduce the environmental impacts for future aircraft.

Microelectromechanical systems (MEMSs) and nanoelectromechanical systems (NEMSs) are revolutionary technologies that merge mechanical and electronic components on microscopic and nanoscopic scales [...].

Today’s commercial aviation industry centers on the tube-and-wing aircraft configuration with underwing-mounted engines, possibly nearing convergence on optimal performance capabilities with acceptable community noise. A potentially feasible breakthrough for obtaining lower noise levels for commercial aviation is the blended-wing–body (BWB), which presents unique noise-reducing characteristics such as engine shielding and simplified high-lift devices. The significance of characteristics unique to BWBs on overall aircraft noise is assessed through a study of a BWB aircraft design representative of the JetZero vehicle. This paper presents a methodology capable of modeling the aircraft’s propulsion system and corresponding performance capabilities necessary to assess the vehicle noise sources and overall community noise impact. Analysis of Part 36 certification noise levels indicates that the vehicle’smarginto Stage 5 standards is 35.8 effective perceived noise level (in EPNdB), and an additional 2.0 EPNdB is achievable with a decreased maximum takeoff thrust engine variant. Community noise impacts of departure and arrival procedures are studied through comparison of single-event noise contours. Significant contour area reductions were observed when compared to conventional tube-and-wing aircraft of similar weight and range class. Further departure and approach noise reductions were modeled through additional full-flight procedure variations.

Passive daytime radiative cooling (PDRC) presents a promising avenue for efficient thermal management without relying on electrical power. In this study, the potential of integrating Hollow Yttrium-Oxide Spheres (HYSs) within a Polydimethylsiloxane (PDMS) matrix to enhance PDRC is investigated. Through a combination of experimental characterization and computational analysis, the optical properties and radiative cooling performance of PDMS films embedded with HYSs are evaluated. These results demonstrate that HYSs significantly improve both solar reflectivity and long-wave infrared (LWIR) emissivity of the PDMS matrix. Finite-Difference Time-Domain (FDTD) simulations confirm the scattering efficiency of HYSs across various wavelength ranges, highlighting their effectiveness as additives for enhancing the radiative properties of passive cooling materials. Experimental validation reveals enhanced reflectivity and emissivity of PDMS films with embedded HYSs, resulting in superior cooling performance compared to non-HYS counterparts. Overall, this study underscores the potential of HYS-infused PDMS films as a promising solution for passive radiative cooling, with broad applicability in diverse domains requiring efficient thermal management solutions. Additionally, these research insights pave the way for establishing an AI database for passive radiative cooling research, offering new avenues for further exploration and application in this field.

In recent decades, electrokinetic handling of microparticles and biological cells found many applications ranging from biomedical diagnostics to microscale assembly. The integration of electrokinetic handling such as dielectrophoresis (DEP) greatly benefits microfluidic point-of-care systems as many modern assays require cell handling. Compared to traditional pump-driven microfluidics, typically used for DEP applications, centrifugal CD microfluidics provides the ability to consolidate various liquid handling tasks in self-contained discs under the control of a single motor. Therefore, it has significant advantages in terms of cost and reliability. However, to integrate DEP on a spinning disc, a major obstacle is transferring power to the electrodes that generate DEP forces. Existing solutions for power transfer lack portability and availability or introduce excessive complexity for DEP settings. We present a concept that leverages the compatibility of DEP and inductive power transfer to bring DEP onto a rotating disc without much circuitry. Our solution leverages the ongoing advances in the printed circuit board market to make low-cost cartridges (<$1) that can employ DEP, which was validated using yeast cells. The resulting DEPDisc platform solves the challenge that existing printed circuit board electrodes are reliant on expensive high-voltage function generators by boosting the voltage using resonant inductive power transfer. This work includes a device costing less than $100 and easily replicable with the information provided in the Supplementary material. Consequently, with DEPDisc we present the first DEP-based low-cost platform for cell handling where both the device and the cartridges are truly inexpensive.

Carbon nanofibers show the advantages of scale effects on electrical and mechanical properties for applications such as aerospace1,2, automotive3,4, and energy5,6, but have to confront the challenge of maximizing the role of scale effects. Here, a method of additive nanostructuring and carbonization of polyacrylonitrile (PAN) jetting for the nano-forming of carbon fibers is developed by understanding the electrostatic submicro-initiation of a PAN jetting, altering the microstructure of PAN-based jetting fibers at the nanoscale and implementing subsequent carbonization of PAN jetting nanofiber. Using this method of additive nanostructuring and carbonization in combination with the radial distribution pattern of shear stress, we find that the conformation of some molecular chains inside the PAN nanofibers is transformed into the zigzag conformation. The ability to materialize and carbonize such PAN nanofibers with various conformational structures in the form of arrays on diverse micro-structures and macro-substrates enables the forming of continuous carbon nanofibers with a diameter of ~20 nm and allows the tensile strength of carbon fibers to be enhanced to 212 GPa through the combination of zigzag conformation and nanoscale effects. These advantages create opportunities for the application of maximizing nanoscale effects that have not previously been technically possible.