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Chest Nov 2022
Topics: Humans; Water; Respiration; Air
PubMed: 36344116
DOI: 10.1016/j.chest.2022.05.024 -
Molecules (Basel, Switzerland) Mar 2021Surface bubbles are present in many industrial processes and in nature, as well as in carbonated beverages. They have motivated many theoretical, numerical and... (Review)
Review
Surface bubbles are present in many industrial processes and in nature, as well as in carbonated beverages. They have motivated many theoretical, numerical and experimental works. This paper presents the current knowledge on the physics of surface bubbles lifetime and shows the diversity of mechanisms at play that depend on the properties of the bath, the interfaces and the ambient air. In particular, we explore the role of drainage and evaporation on film thinning. We highlight the existence of two different scenarios depending on whether the cap film ruptures at large or small thickness compared to the thickness at which van der Waals interaction come in to play.
Topics: Air; Microbubbles; Surface Properties; Water
PubMed: 33804584
DOI: 10.3390/molecules26051317 -
Current Biology : CB Oct 2022Much of the awe that humans have for the flight of birds derives from our earthbound habits and our bias toward emphasizing visual cues for interpreting processes in the...
Much of the awe that humans have for the flight of birds derives from our earthbound habits and our bias toward emphasizing visual cues for interpreting processes in the world. Although we move through it and breathe it, air is vastly less dense than our bodies, so it is fanciful to imagine moving our limbs in a manner that would enable us to support our weight in the air. Moreover, air is invisible to us unless we use special tools to reveal its flow patterns. As evidence of our visual bias, contemplate a strong wind. You probably form a mental image of leaves moving on tree branches, or dust swirling about in a tornado, in both cases, solids moving in response to the force of the wind rather than the essence of the wind itself.
Topics: Animals; Humans; Flight, Animal; Birds; Wind; Cues; Dust
PubMed: 36283374
DOI: 10.1016/j.cub.2022.07.007 -
Journal of Environmental Radioactivity Jul 2021Exposure assessment from radionuclides and other soil-bound contaminants often requires quantifying the amount of contaminant resuspended in the air. Rates and... (Review)
Review
Exposure assessment from radionuclides and other soil-bound contaminants often requires quantifying the amount of contaminant resuspended in the air. Rates and controlling factors of radionuclide resuspension and wind erosion of soil are clearly related but have largely been studied separately. Here, we review both and then integrate wind erosion measurements with the radiological resuspension paradigm to provide better estimates of resuspension factors across a broad range of ecosystems and environmental conditions. Radionuclide resuspension by wind was initially investigated during the era of aboveground nuclear weapons testing. Predictive dose models were developed from empirically-derived ratios of air and soil concentrations, otherwise called the resuspension factor. Resuspension factors were shown to generally predict radionuclide concentrations in air, but they were site-specific and largely derived from the arid and semi-arid environments surrounding nuclear weapons testing locations. In contrast, wind erosion studies from the agricultural and environmental sciences have produced more mechanistic models and a relatively robust data set of wind erosion rates and model parameters across a range of ecosystems. We sequentially show the mathematics linking measured sediment flux from wind erosion rate measurements to resuspension factors using the concept of transport capacity and its relationship to the deposition velocity. We also describe the conceptual framework describing how resuspension factors change through time and the mathematical models describing this decrease. We then show how vertical mass flux measurements across ecosystems were categorized and used to calculate ecosystem-based resuspension factors. These calculations allow generalized estimation of radionuclide resuspension factors across ecosystem types as a function of disturbance and as input for dose calculations.
Topics: Ecosystem; Radiation Monitoring; Radioisotopes; Soil; Wind
PubMed: 33774592
DOI: 10.1016/j.jenvrad.2021.106586 -
Journal of Oleo Science Jun 2020The surface charge/surface potential of the air/water interface plays a key role in many natural and industrial processes. Since the first decade of the 20 century,... (Review)
Review
The surface charge/surface potential of the air/water interface plays a key role in many natural and industrial processes. Since the first decade of the 20 century, there are many theoretical proposals to describe the surface charge in the presence of different moieties. However, a complete and consistent description of the interfacial layer remains elusive. More recently, the theoretical frameworks and experimental data get complementary support from the simulation at a molecular level. This paper reviews the recent developments from the theoretical, experimental and simulation aspects. The combined results indicated that the interaction between hydration shells of adsorbed ions and the H-bonds network of surface water plays a critical role in the ionic adsorption. The factor should be incorporated into the conventional theories to correctly predict the ion distribution near the air/water surface.
Topics: Adsorption; Air; Hydrogen Bonding; Ions; Surface Properties; Water
PubMed: 32404551
DOI: 10.5650/jos.ess20024 -
Proceedings. Biological Sciences Dec 2023In everyday life during terrestrial locomotion our body interacts with two media opposing the forward movement of the body: the ground and the air. Whereas the work done...
In everyday life during terrestrial locomotion our body interacts with two media opposing the forward movement of the body: the ground and the air. Whereas the work done to overcome the ground reaction force has been extensively studied, the work done to overcome still air resistance has been only indirectly estimated by means of theoretical studies and by measurements of the force exerted on puppets simulating the geometry of the human body. In this study, we directly measured the force exerted by still air resistance on eight male subjects during walking and running on an instrumented treadmill with a belt moving at the same speed of a flow of laminar air facing the subject. Overall, the coefficient of proportionality between drag and velocity squared () was smaller during running than walking. During running decreased progressively with increasing average velocity up to an apparently constant, velocity independent value, similar to that predicted in the literature using indirect methods. A predictive equation to estimate drag as a function of the speed and the height of the running subject is provided.
Topics: Humans; Male; Biomechanical Phenomena; Gait; Locomotion; Mechanical Phenomena; Running; Walking; Air
PubMed: 38087922
DOI: 10.1098/rspb.2023.1763 -
Journal of Visualized Experiments : JoVE Sep 2020We report two methods to create zinc-sponge electrodes that suppress dendrite formation and shape change for rechargeable zinc batteries. Both methods are characterized...
We report two methods to create zinc-sponge electrodes that suppress dendrite formation and shape change for rechargeable zinc batteries. Both methods are characterized by creating a paste made of zinc particles, organic porogen, and viscosity-enhancing agent that is heated under an inert gas and then air. During heating under the inert gas, the zinc particles anneal together, and the porogen decomposes; under air, the zinc fuses and residual organic burns out, yielding an open-cell metal foam or sponge. We tune the mechanical and electrochemical properties of the zinc sponges by varying zinc-to-porogen mass ratio, heating time under inert gas and air, and size and shape of the zinc and porogen particles. An advantage of the reported methods is their ability to finely tune zinc-sponge architecture. The selected size and shape of the zinc and porogen particles influence the morphology of the pore structure. A limitation is that resulting sponges have disordered pore structures that result in low mechanical strength at low volume fractions of zinc (<30%). Applications for these zinc-sponge electrodes include batteries for grid-storage, personal electronics, electric vehicles, and electric aviation. Users can expect zinc-sponge electrodes to cycle up to 40% depth of discharge at technologically relevant rates and areal capacities without the formation of separator-piercing dendrites.
Topics: Air; Dendrites; Electric Power Supplies; Electrochemistry; Electrodes; Mechanical Phenomena; Porosity; Zinc
PubMed: 33074262
DOI: 10.3791/61770 -
Cell and Tissue Research Jan 2021Extant anuran amphibians originate from an evolutionary intersection eventually leading to fully terrestrial tetrapods. In many ways, they have to deal with exposure to... (Review)
Review
Extant anuran amphibians originate from an evolutionary intersection eventually leading to fully terrestrial tetrapods. In many ways, they have to deal with exposure to both terrestrial and aquatic environments: (i) phylogenetically, as derivatives of the first tetrapod group that conquered the terrestrial environment in evolution; (ii) ontogenetically, with a development that includes aquatic and terrestrial stages connected via metamorphic remodeling; and (iii) individually, with common changes in habitat during the life cycle. Our knowledge about the structural organization and function of the amphibian olfactory system and its relevance still lags behind findings on mammals. It is a formidable challenge to reveal underlying general principles of circuity-related, cellular, and molecular properties that are beneficial for an optimized sense of smell in water and air. Recent findings in structural organization coupled with behavioral observations could help to understand the importance of the sense of smell in this evolutionarily important animal group. We describe the structure of the peripheral olfactory organ, the olfactory bulb, and higher olfactory centers on a tissue, cellular, and molecular levels. Differences and similarities between the olfactory systems of anurans and other vertebrates are reviewed. Special emphasis lies on adaptations that are connected to the distinct demands of olfaction in water and air environment. These particular adaptations are discussed in light of evolutionary trends, ontogenetic development, and ecological demands.
Topics: Air; Amphibians; Animals; Receptors, Odorant; Water
PubMed: 33496878
DOI: 10.1007/s00441-020-03377-5 -
Medical Gas Research 2023The noble gas argon has demonstrated biological activity that may prove useful as a medical intervention. Pharmacokinetics, the disposition of the drug molecule in the...
The noble gas argon has demonstrated biological activity that may prove useful as a medical intervention. Pharmacokinetics, the disposition of the drug molecule in the body through time, is fundamental necessary knowledge to drug discovery, development and even post-marketing. The fundamental measurement in pharmacokinetic studies is blood concentration of the molecule (and its metabolites) of interest. While a physiologically based model of argon pharmacokinetics has appeared in the literature, no experimental data have been published. Thus, argon pharmaceutical development requires measurement of argon solubility in blood. This paper reports on the development of a technique based on mass spectrometry for measuring argon solubility in liquids, including blood, to be further employed in pharmacokinetics testing of argon. Based on a prototype, results are reported from sensitivity experiments using ambient air, water and rabbit blood. The key takeaway is that the system was sensitive to argon during all of the testing. We believe the technique and prototype of the quadrupole mass spectrometer gas analyzer will be capable of inferring argon pharmacokinetics through the analysis of blood samples.
Topics: Animals; Rabbits; Argon; Solubility; Mass Spectrometry; Air; Water
PubMed: 37077120
DOI: 10.4103/2045-9912.351106 -
Small (Weinheim An Der Bergstrasse,... Oct 2021Wet adhesion is greatly demanded in fields of wearable devices, wound dressings, and smart robotics. However, reusable, noninvasive and convenient adhesive pads in the...
Wet adhesion is greatly demanded in fields of wearable devices, wound dressings, and smart robotics. However, reusable, noninvasive and convenient adhesive pads in the liquid environment have remained a challenge. Here, a novel concept of underwater adhesion inspired by the diving beetle, which utilizes the air bubbles as an adhesive to realize nondestructive and repeatable adhesion working across a wide range of scales is shown. The mechanism of underwater bubble adhesion is revealed by the capillarity of air-bubble bridge, of which the property depends on the dynamic bubble contact angles and the gap distance. The design principle of the air bubble-based underwater adhesion is proposed and validated to tune the interfacial acting force by theoretical and experimental results. Finally, a strong, reusable surface adhesive based on air bubble bridges is demonstrated from macro- to microscales in applications of particle manipulation and particle self-assembly. This unique view of underwater bubble adhesion provides new ideas for broader applications.
Topics: Adhesives; Air; Animals; Coleoptera; Physical Phenomena; Surface Tension
PubMed: 34554641
DOI: 10.1002/smll.202103423