scholarly journals Effect of Gas Type and Its Pressure on Nanobubble Generation

2021 ◽  
Vol 9 ◽  
Author(s):  
Nikolai F. Bunkin ◽  
Alexey V. Shkirin ◽  
Nikita V. Penkov ◽  
Mikhail V. Goltayev ◽  
Pavel S. Ignatiev ◽  
...  
Keyword(s):  
Sharp Increase ◽  
Saline Solution ◽  
External Pressure ◽  
Deionized Water ◽  
Number Density ◽  
Saturated Water Vapor ◽  
Volume Number ◽  
Saturated Water ◽  
External Pressures ◽  
Gas Molecules

The dependence of the volume number density of ion-stabilized gas nanobubbles (bubstons) on the type of gas and the pressure created by this gas in deionized water and saline solution has been investigated. The range of external pressures from the saturated water vapor (17 Torr) to 5 atm was studied. It turned out that the growth rate of the volume number density of bubstons is controlled by the magnitude of the molecular polarizability of dissolved gases. The highest densities of bubstons were obtained for gases whose molecules have a dipole moment. At fixed external pressure and the polarizability of gas molecules, the addition of external ions leads to a sharp increase in the content of bubstons.

Electron and ion transport in gaseous methanol and water: density and temperature effects

1983 ◽  
Vol 61 (7) ◽  
pp. 1664-1670 ◽  
Author(s):  
Norman Gee ◽  
Gordon R. Freeman
Keyword(s):  
Water Vapor ◽  
Cross Section ◽  
Cross Sections ◽  
Saturated Vapor ◽  
Water Density ◽  
Saturated Water Vapor ◽  
Methanol Vapor ◽  
Flexible Molecules ◽  
Saturated Water ◽  
Gas Molecules

Electron and cation mobilities in methanol and water vapor measured at 293 ≤ T (K) ≤ 617 were used to estimate the corresponding momentum transfer cross sections. The electron cross sections correlate with the square of the dipole moment. Unlike the nonpolar gases, where the average cross section for electrons σavc.c is only 0.01–0.1 times that for cations σavc.+, methanol has σav.c ≈ 0.5σavc.+ and water has σavc.c ≈ σavc.+. The thermal electrons exchange energy with the molecules mainly through molecular rotational modes, as opposed to elastic modes.The onset of electron quasilocalization in the saturated vapor occurs at nql ≈ 5 × 1025 molecules/m3 (nql/nc = 0.010) in methanol and 3 × 1025 (nql/nc ≈ 0.003) in water. These are about 10-fold lower densities than in hydrocarbons, where nql/nc ≈ 0.1. The loffe–Regel limit for quasifree states gives nql ≈ 0.36 × (Tnμc)ql, which holds quite well when the gas molecules are relatively rigid. However, for flexible molecules such as the n-alkanes larger than propane, the loffe–Regal limit predicts too large values for nql.The density normalized mobility of cations nμ+ in saturated methanol vapor is constant at 1.02 × 1021 molecules/m V s up to 67 × 1025 molecules/m3 (25 Amagats). In saturated water vapor nμ+ = 1.87 × 1021 molecules/m V s up to 30 × 1025 molecules/m3 (11 Amagats).

Replication of Wet Objects and Cells

1974 ◽  
Vol 32 ◽  
pp. 102-103
Author(s):  
S. Basu ◽  
D. F. Parsons
Keyword(s):  
Water Vapor Pressure ◽  
High Vacuum ◽  
Polystyrene Latex ◽  
Vacuum System ◽  
Saturated Water Vapor ◽  
Replication Method ◽  
New Methods ◽  
Saturated Water ◽  
Water Vapors ◽  
Intermediate Chamber

We are approaching the invasiveness of cancer cells from the studies of their wet surface morphology which should distinguish them from their normal counterparts. In this report attempts have been made to provide physical basis and background work to a wet replication method with a differentially pumped hydration chamber (Fig. 1) (1,2), to apply this knowledge for obtaining replica of some specimens of known features (e.g. polystyrene latex) and finally to realize more specific problems and to improvize new methods and instrumentation for their rectification. In principle, the evaporant molecules penetrate through a pair of apertures (250, 350μ), through water vapors and is, then, deposited on the specimen. An intermediate chamber between the apertures is pumped independently of the high vacuum system. The size of the apertures is sufficiently small so that full saturated water vapor pressure is maintained near the specimen.

ESEM - A multipurpose surface Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 632-633 ◽  
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Environmental Scanning ◽  
Gas Composition ◽  
Saturated Water Vapor ◽  
Surface Electron ◽  
Current State ◽  
Saturated Water ◽  
New Type ◽  
Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

scholarly journals Depressurization-Induced Nucleation in the “Polylactide-Carbon Dioxide” System: Self-Similarity of the Bubble Embryos Expansion

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1115
Author(s):  
Dmitry Zimnyakov ◽  
Marina Alonova ◽  
Ekaterina Ushakova
Keyword(s):  
Initial Rate ◽  
Initial Pressure ◽  
External Pressure ◽  
Self Similarity ◽  
Embryo Formation ◽  
Linear Behavior ◽  
Joint Influence ◽  
External Pressures ◽  
Adiabatic Cooling ◽  
Self Similar

Self-similar expansion of bubble embryos in a plasticized polymer under quasi-isothermal depressurization is examined using the experimental data on expansion rates of embryos in the CO2-plasticized d,l-polylactide and modeling the results. The CO2 initial pressure varied from 5 to 14 MPa, and the depressurization rate was 5 × 10−3 MPa/s. The constant temperature in experiments was in a range from 310 to 338 K. The initial rate of embryos expansion varied from ≈0.1 to ≈10 µm/s, with a decrease in the current external pressure. While modeling, a non-linear behavior of CO2 isotherms near the critical point was taken into account. The modeled data agree satisfactorily with the experimental results. The effect of a remarkable increase in the expansion rate at a decreasing external pressure is interpreted in terms of competing effects, including a decrease in the internal pressure, an increase in the polymer viscosity, and an increase in the embryo radius at the time of embryo formation. The vanishing probability of finding the steadily expanding embryos for external pressures around the CO2 critical pressure is interpreted in terms of a joint influence of the quasi-adiabatic cooling and high compressibility of CO2 in the embryos.

Generation of aerosol and droplets in binary mixtures of saturated water vapor with air and molecular gases

2016 ◽  
Vol 29 (2) ◽  
pp. 127-134 ◽  
Author(s):  
A. V. Klimkin ◽  
A. N. Kuryak ◽  
Yu. N. Ponomarev ◽  
A. S. Kozlov ◽  
S. B. Malyshkin ◽  
...  
Keyword(s):  
Water Vapor ◽  
Binary Mixtures ◽  
Saturated Water Vapor ◽  
Molecular Gases ◽  
Saturated Water

scholarly journals An Investigation of the Basic Physics of Irrigation in Urology and the Role of Automated Pump Irrigation in Cystoscopy

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Dwayne Chang ◽  
Rustom P. Manecksha ◽  
Konstantinos Syrrakos ◽  
Nathan Lawrentschuk
Keyword(s):  
Flow Rate ◽  
External Pressure ◽  
Flow Rates ◽  
Pumping System ◽  
External Pressures ◽  
Basic Physics ◽  
Traditional Irrigation ◽  
Irrigation Solution ◽  
Bladder Fullness

Objective. To investigate the effects of height, external pressure, and bladder fullness on the flow rate in continuous, non-continuous cystoscopy and the automated irrigation fluid pumping system (AIFPS).Materials. Each experiment had two 2-litre 0.9% saline bags connected to a continuous, non-continuous cystoscope or AIFPS via irrigation tubing. Other equipment included height-adjustable drip poles, uroflowmetry devices, and model bladders.Methods. In Experiment 1, saline bags were elevated to measure the increment in flow rate. In Experiment 2, saline bags were placed under external pressures to evaluate the effect on flow rate. In Experiment 3, flow rate changes in response to variable bladder fullness were measured.Results. Elevating saline bags caused an increase in flow rates, however the increment slowed down beyond a height of 80 cm. Increase in external pressure on saline bags elevated flow rates, but inconsistently. A fuller bladder led to a decrease in flow rates. In all experiments, the AIFPS posted consistent flow rates.Conclusions. Traditional irrigation systems were susceptible to changes in height of irrigation solution, external pressure application, and bladder fullness thus creating inconsistent flow rates. The AIFPS produced consistent flow rates and was not affected by any of the factors investigated in the study.

Influence of Ambient Temperature on Course of Cement Stone Solidification

2018 ◽  
Vol 760 ◽  
pp. 61-66
Author(s):  
Marcela Fridrichová ◽  
Dominik Gazdič ◽  
Karel Dvořák
Keyword(s):  
High Temperature ◽  
Reference Sample ◽  
Xrd Analysis ◽  
Hydration Process ◽  
Cement Stone ◽  
Hardened Cement ◽  
Saturated Water Vapor ◽  
Saturated Water ◽  
Negative Effect

The aim of the work was to investigate the influence of extremely low and high temperature on the course of hydration of cement stone compared to the reference sample hydrated at normal conditions. The work was structured in such a way that Portland cement was first subjected to standard technological tests. Next, sets of test prisms using cement paste were prepared. This samples were immediately exposed to saturated water vapor in three temperature environments: 5 °C, 20 °C and 80 °C. The course of the hydration process during the first 28 days was monitored by the determination of the phase composition by XRD analysis and thermal analysis, and mediated by means of determination of tensile strength after bending and compressive strength. The low temperature did not have a negative effect on the final properties of the hardened cement stone. On the other hand, high temperature accelerated the initial phase of the hydration process, but negatively affected the resulting mechanical parameters

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