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Alginate aerogel/glass and carbon fiber composite substitutes for balsa cores in wind turbine blades
Get PDFEuthanasia: A Cross-Cultural Analysis of Right-to-Die Organzations and Euthanasia Legislature in the Netherlands and United States
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Effects Of Micromachining on Anti-Oxidant Elution From a Mechanically-Adaptive Polymer
Get PDFIntracortical microelectrodes (IMEs) can be used to restore motor and sensory function as a part of brain–computer interfaces in individuals with neuromusculoskeletal disorders. However, the neuroinflammatory response to IMEs can result in their premature failure, leading to reduced therapeutic efficacy. Mechanically-adaptive, resveratrol-eluting (MARE) neural probes target two mechanisms believed to contribute to the neuroinflammatory response by reducing the mechanical mismatch between the brain tissue and device, as well as locally delivering an antioxidant therapeutic. To create the mechanically-adaptive substrate, a dispersion, casting, and evaporation method is used, followed by a microfabrication process to integrate functional recording electrodes on the material. Resveratrol release experiments were completed to generate a resveratrol release profile and demonstrated that the MARE probes are capable of long-term controlled release. Additionally, our results showed that resveratrol can be degraded by laser-micromachining, an important consideration for future device fabrication. Finally, the electrodes were shown to have a suitable impedance for single-unit neural recording and could record single units in vivo
Big Geospatiotemporal Data Approaches to Monitoring and Mitigating Environmental Impacts in Agriculture
Get PDFThis research explores the application of geospatial techniques for global agricultural monitoring, integrating satellite imagery and soil data to assess crop health and soil conditions. Our approach provides actionable insights to improve agricultural productivity and sustainability, addressing food security challenges through advanced machine learning models
Biomechanics of Transduction by Mechanosensory Cilia for Prey Detection in Aquatic Organisms
No full textSurface-feeding aquatic animals navigate towards the source of water disturbances and must differentiate prey from other environmental stimuli. Medicinal leeches locate prey, in part, using a distribution of mechanosensory hairs along their body that deflect under fluid flow. Leech\u27s behavioral responses to surface wave temporal frequency are well documented. However, a surface wave\u27s temporal frequency depends on many underlying environmental and fluid properties that vary substantially in natural habitats (e.g., water depth, temperature). The impact of these variables on neural response and behavior is unknown. Here, we developed a physics-based leech mechanosensor model to examine the impact of environmental and fluid properties on neural response. Our model used the physical properties of a leech cilium and was verified against existing behavioral and electrophysiological data. The model\u27s peak response occurred with waves where the effects of gravity and surface tension were nearly equal (i.e., the phase velocity minimum). This suggests that preferred stimuli are related to the interaction between fundamental properties of the surrounding medium and the mechanical properties of the sensor. This interaction likely tunes the sensor to detect the nondispersive components of the signal, filtering out irrelevant ambient stimuli, and may be a general property of cilia across the animal kingdom
Impact of Resin Molecular Weight on Drying Kinetics and Sag of Coatings
No full textCoating performance is influenced by factors inherent to formulation design and processing conditions. Understanding the complex interplay of these attributes enables for mitigating defects, such as sag, which is a gravity-driven phenomenon that impacts the aesthetic and functionality of a coating. The work herein investigates the impact of resin molecular weight and solvent choice on the drying kinetics and sag velocity in polymer films. These films, ranging in thickness from ~60 μm to ~120 μm were formulated with 45 % by weight polymer resin in one of two solvent packages with different relative evaporation rates (RER). Gravimetry was initially used to track drying rate and a one-dimensional diffusion model was utilized to compute the apparent solvent diffusivity. In addition, the film thickness was tracked with optical profilometry. Results from these measurements showed that for fixed molecular weight the drying rate increased by approximately two-fold for the high RER solvent, whereas the apparent diffusivity tended to increase with increasing polymer molecular weight. Films formulated from higher molecular weight resins had greater initial viscosities and thicknesses for identical draw down blade clearance. By extension, the higher apparent diffusivities at greater molecular weights were attributed to effects of prolonged evaporation times for the thicker films. The sag velocity was measured through the thickness of the film for these systems at a 5° incline using the Variable Angle Inspection Microscope (VAIM). Measurements showed an increase in sag velocity for thinner and less viscous films, which was somewhat surprising both because a thinner film will experience lower gravitational stress and quicker drying times as compared to a thicker film. From these data we conclude that formulating a coating with higher molecular weight resin, although likely to increase drying time, will tend to deter sag because of the large impact of viscosity on these phenomena
Sex Differences Among Older Adults With Bipolar Disorder: Results From the Global Aging & Geriatric Experiments in Bipolar Disorder (GAGE-BD) Project
No full textObjective: Sex-specific research in adult bipolar disorder (BD) is sparse and even more so among those with older age bipolar disorder (OABD). Knowledge about sex differences across the bipolar lifespan is urgently needed to target and improve treatment. To address this gap, the current study examined sex differences in the domains of clinical presentation, general functioning, and mood symptoms among individuals with OABD. Methods: This Global Aging & Geriatric Experiments in Bipolar Disorder (GAGE-BD) study used data from 19 international studies including BD patients aged ≥50 years (N = 1,185: 645 women, 540 men).A comparison of mood symptoms between women and men was conducted initially using two-tailed t tests and then accounting for systematic differences between the contributing cohorts by performing generalized linear mixed models (GLMMs). Associations between sex and other clinical characteristics were examined using GLMM including: age, BD subtype, rapid cycling, psychiatric hospitalization, lifetime psychiatric comorbidity, and physical health comorbidity, with study cohort as a random intercept. Results: Regarding depressive mood symptoms, women had higher scores on anxiety and hypochondriasis items. Female sex was associated with more psychiatric hospitalizations and male sex with lifetime substance abuse disorders. Conclusion: Our findings show important clinical sex differences and provide support that older age women experience a more severe course of BD, with higher rates of psychiatric hospitalization. The reasons for this may be biological, psychological, or social. These differences as well as underlying mechanisms should be a focus for healthcare professionals and need to be studied further
Numerical Study of the Effects of Confinement on Large-Scale Fires in Microgravity
No full textConfinement has been shown to play an important role on burning behavior of solid materials in microgravity. Previous studies using small flow ducts (duct height \u3c 7.6 cm) concluded that the flame spread rate is linear to the inverse of the duct height. The underlying physics for this correlation is the combustion thermal expansion that leads to different flow acceleration in different flow duct cross-section areas. In recent NASA microgravity fire experiments, Saffire, wide solid fuel samples were burned in two large flow ducts. In these experiments, the duct heights (30 cm and 50 cm) were significantly larger than the flame standoff distance (∼1 cm) and the effect of thermal expansion was expected to be minimal. However, the experiment results showed that both flame spread rate and pyrolysis length increased more than 95 % when the duct height decreased by 40 %. To understand the underlying physics of the experimental results, two-dimensional transient numerical simulations are performed. The model configuration is based on the Saffire experiments. The model successfully predicts the transient flame development processes and the flame spread rates observed at both duct heights. In addition, a methodology is developed to deduce net heat flux distribution on the sample surface using thermocouple data obtained in the experiments. The deduced heat flux profiles in the experiments and in the numerical results agree qualitatively and quantitively. After the model is validated against the experimental data, a parametric study on the duct height is performed. When duct height decreases, flame spread rate increases. It is found that, at large duct heights (\u3e 20 cm), the inverse of the flame spread rate has a linear dependency on the inverse of the duct height. Analytical analysis of cold flow (without combustion) demonstrates that this relationship is due to the different flow profiles on duct cross-section plane when duct height varies (i.e., a hydrodynamic effect). Effects of duct ceiling radiation properties are also considered. Radiation reflection from the duct ceiling increases the heat input on the sample surface, resulting in an increased flame spread rate. This effect is stronger at a smaller duct height
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