Investigation of long-term effect of a reduced pressure oxygen atmosphere on animals and man
Effects on animals and human beings subjected to prolonged confinement in reduced pressure and high oxygen environments
Genin, A. M.↗
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Results for “Pressure effect”
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Effect of plasma on gas flow and air concentration in the effluent of a pulsed cold atmospheric pressure helium plasma jet
In this work, we report on the flow effects induced by a nanosecond pulsed helium cold atmospheric pressure plasma jet impinging on a glass substrate. Herein, gas temperature measurements have been performed using optical emission spectroscopy including rotational spectra of OH(A-X) (0,0) and N 2 (C-B) (0,0) and resonance broadening of a helium emission line at 667.8 nm. The measured increase in gas temperature was less than 15 K. We have measured the air concentration distribution in the jet effluent by means of Rayleigh scattering exploiting the large difference in Rayleigh cross-section of air and helium. The obtained results show that the plasma causes a broadening of the helium channel suggesting an enhanced gas velocity and mixing with the ambient air. The impact of the plasma on the jet effluent is polarity dependent and is larger in the case of positive applied voltage pulses. Using an estimation of the increased gas velocity required to obtain the observed air concentrations, we have shown that both gas heating and electrohydrodynamic (EHD) forces related to the propagation of an ionization front are not causing the observed phenomena. The surface charge which can exist for a much longer time than the duration of the applied voltage pulse is the primary cause of the EHD forces on the bulk charges which lead to significant different air concentration profiles in the jet effluent for plasma on and off.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Survival of Massive Star-forming Galaxies in Cluster Cores Drives Gas-phase Metallicity Gradients: The Effects of Ram Pressure Stripping
Recent observations of galaxies in a cluster at z = 0.35 show that their integrated gas-phase metallicities increase with decreasing cluster-centric distance. To test whether ram pressure stripping (RPS) is the underlying cause, we use a semianalytic model to quantify the “observational bias” that RPS introduces into the aperture-based metallicity measurements. We take integral field spectroscopy of local galaxies, remove gas from their outer galactic disks via RPS, and then conduct mock slit observations of cluster galaxies at z = 0.35. Our RPS model predicts a typical cluster-scale metallicity gradient of −0.03 dex/Mpc. By removing gas from the outer galactic disks, RPS introduces a mean metallicity enhancement of +0.02 dex at a fixed stellar mass. This gas removal and subsequent quenching of star formation preferentially removes low-mass cluster galaxies from the observed star-forming population. As only the more massive star-forming galaxies survive to reach the cluster core, RPS produces a cluster-scale stellar mass gradient of −0.05log(M{sub ∗}/M{sub ⊙})/Mpc. This mass segregation drives the predicted cluster-scale metallicity gradient of −0.03 dex/Mpc. However, the effects of RPS alone cannot explain the higher metallicities measured in cluster galaxies at z = 0.35. We hypothesize that additional mechanisms including steep internal metallicity gradients and self-enrichment due to gas strangulation are needed to reproduce our observations at z = 0.35.
79 ASTRONOMY AND ASTROPHYSICS↗
Dual effects of atmospheric pressure plasma jet on skin wound healing of mice
ABSTRACT Cold plasma has become an attractive tool for promoting wound healing and treating skin diseases. This article presents an atmospheric pressure plasma jet (APPJ) generated in argon gas through dielectric barrier discharge, which was applied to superficial skin wounds in BALB/c mice. The mice ( n = 50) were assigned randomly into five groups (named A, B, C, D, E) with 10 animals in each group. Natural wound healing was compared with stimulated wound healing treated daily with APPJ for different time spans (10, 20, 30, 40, and 50 seconds) on 14 consecutive days. APPJ emission spectra, morphological changes in animal wounds, and tissue histological parameters were analyzed. Statistical results revealed that wound size changed over the duration of the experimental period and there was a significant interaction between experimental day and group. Differences between group C and other groups at day 7 were statistically significant ( p < 0.05). All groups had nearly achieved closure of the untreated control wounds at day 14. The wounds treated with APPJ for 10, 20, 30, and 40 seconds showed significantly enhanced daily improvement compared with the control and almost complete closure at day 12, 10, 7, and 13, respectively. The optimal results of epidermal cell regeneration, granulation tissue hyperplasia, and collagen deposition in histological aspect were observed at day 7. However, the wounds treated for 50 seconds were less well healed at day 14 than those of the control. It was concluded that appropriate doses of cold plasma could inactivate bacteria around the wound, activate fibroblast proliferation in wound tissue, and eventually promote wound healing. Whereas, over doses of plasma suppressed wound healing due to causing cell death by apoptosis or necrosis. Both positive and negative effects may be related to the existence of reactive oxygen and nitrogen species (ROS and RNS) in APPJ.
Xu, Gui‐Min↗
The Effect of Valve Cooling upon Maximum Permissible Engine Output as Limited by Knock
A Wright GR-1820-G200 cylinder was tested over a wide range of fuel-air ratios at maximum permissible power output as limited by knock with three different degrees of valve cooling. The valves used were stock valves (solid inlet valve and hollow sodium-cooled exhaust valve), hollow valves with no coolant, and hollow valves with flowing water as a coolant. Curves showing the variation in maximum permissible values of inlet-air pressure, indicated mean effective pressure, cylinder charge, and indicated specific fuel consumption with change in fuel-air ratio and valve cooling are shown. The use of valves cooled by a stream of water passing through their hollow interiors permitted indicated mean effective pressures 10 percent higher than the mean effective pressures permissible with stock valves when the engine was operated with fuel-air ratios from 0.055 to 0.065. Operation of the engine with lean mixtures with uncooled hollow valves resulted in power output below the output obtained with the stock valves. The data show an increase in maximum permissible indicated mean effective pressure due to cooling the valves, which averages only 2.1 percent with fuel-air ratios from 0.075 to 0.105.
Munger, Maurice↗
2D photofragmentation LIF imaging of H 2 O 2 and HO 2 in the effluent of an atmospheric-pressure plasma jet: effects of solid and liquid interfaces
Two-dimensional (2D) absolute measurements of hydrogen peroxide (H 2 O 2 ) and approximations of the hydroperoxyl radical (HO 2 ) in the effluent of a COST Reference Microplasma Jet operated with a He/H 2 O feed gas are presented. Gas-phase densities are mapped using photofragmentation laser-induced fluorescence (PF-LIF) under three boundary conditions: open effluent, a solid target, and a liquid target. A novel method is presented for separating PF-LIF signals from H 2 O 2 and HO 2 using comparative measurements in oxygen-rich and oxygen-free environments to exploit the preferential formation of HO 2 in the presence of molecular oxygen. This separation strategy is supported by results from a plug-flow plasma chemistry model. Measured densities agree closely with model predictions in both magnitude and trend, while the 2D experimental distributions provide additional insight into the spatial dependencies of these species. In particular, the results show distinct differences in species transport depending on the target type: solid surfaces induce lateral deflection and reduced centerline densities, whereas liquid interfaces promote axial accumulation and higher near-axis concentrations.
atmospheric-pressure plasma jet (APPJ)↗
The problem of the effect of breathing oxygen in the resorption of gas emboli in the vascular system of an animal and on the course of pulmonary pressure trauma
Effect of oxygen breathing in resorption of gas embolism in vascular system of cats and on course of pulmonary pressure trauma
PULMONARY CIRCULATION↗
Effect of random fluctuations in pressure gradient on channel flow
Effect of random fluctuations in pressure gradient on channel flow
Perlmutter, M.↗
Pressure versus Temperature Effects on Intramolecular Electron Transfer in Mixed-Valence Complexes
Abstract not provided
Scheins, Stephan↗
Effectiveness of subsurface pressure monitoring for brine leakage detection in an uncertain CO2 sequestration system
Explore the source record for details and available documents.
CO2 sequestration↗
Effects of Forming Pressure on Physicochemical Properties of YBCO Ceramics
This article details the solid-state synthesis of high-temperature superconducting YBa{sub 2}Cu{sub 3}O{sub 7−x}. Tests were carried out on samples formed at different pressures (200, 400, 600 and 800 MPa) before being annealed under pure oxygen. The X-ray diffraction method showed that, regardless of the forming pressure, the samples contain about 97 wt.% of Y-123 phase. SEM images showed a polycrystalline structure of samples of similar grain size and number of pores (intergranular spaces). The values of critical temperatures (T{sub c0}), determined from magnetoresistance measurements, are about 91.5 K for all samples, and the T{sub c0} temperatures do not depend on sample-forming pressure. Magnetoresistance measurements have shown that samples formed with higher pressures exhibit smaller changes in T{sub c0} and superconducting transition width ΔT due to the influence of the H{sub DC} magnetic field, than the samples formed with lower pressures. Values of specific resistance determined by the use of van der Pauw method at 300 K is about 2 mΩcm for all samples. The critical temperatures (T cintra) of grains and critical current densities at 77 K were determined from AC magnetic susceptibility measurements, and they are about 91.6 K and 400 A cm{sup −2}, respectively.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Effect of Oxygen Pressure on Thermoelectric Properties of p-Type CuAlO{sub 2} Films Fabricated by Pulsed Laser Deposition
We focus on the growth of p-type CuAlO{sub 2} thin films and its thermoelectric properties. Thin films are deposited by pulsed laser deposition technique on single-crystal sapphire substrates varying the oxygen partial pressure. Thin film deposited at oxygen partial pressure of 200 mTorr presents bigger grains (about 10 μm in size) and shows Seebeck coefficient as high as 270 µV/K with a conductivity of about 0.8 S/cm so that its power factor is about 5.7 µW/mK{sup 2} at 800 K, twice than observed in the film deposited at 60 mTorr of oxygen.
36 MATERIALS SCIENCE↗
Enhanced Mechanical, Tribological, and Thermal Properties of Fe{sub 3}Al Composites with Carbon Nanotubes
In this work, Fe{sub 3}Al-based composites reinforced with carbon nanotubes were fabricated by a hot-press sintering process under various sintering pressures. The effects of sintering pressure and additives (alumina and lanthanum) on both the physical and the mechanical properties were systematically investigated. Results showed that with the sintering pressure of 15 MPa and incorporation of carbon nanotubes (CNTs), the microhardness of Fe{sub 3}Al composite exhibited a peak value at 1038.1 HV, which was ~ 60% higher than those without the addition of carbon nanotubes (644.9 HV). Also, both the compressive yield strength and the thermal conductivity of Fe{sub 3}Al composite were also significantly improved. Results of wear test showed the Fe{sub 3}Al composite exhibited a low wearing rate (10{sup −6}-10{sup −5} order of magnitude) and a friction coefficient (0.53-0.67).
36 MATERIALS SCIENCE↗
Numerical study of turbulent non-premixed cool flames at high and supercritical pressures: Real gas effects and dual peak structure
Not Available
Ramachandran, Suryanarayan (ORCID:0000000166862058↗
Effect on blood pressure and eye health symptoms in a climate-financed randomized cookstove intervention study in rural India
Highlights: • Health benefits from a climate-financed cookstove intervention were limited. • Blood pressure changes were not significant in homes using intervention stoves. • Eye-irritation generally improved, suggesting unmeasured exposures or reporting bias. • Stove adoption and use behavior, in addition to stove technology, can complicate attainment of health benefits. Air pollution from cooking with solid fuels is a potentially modifiable risk factor for increased blood pressure and may lead to eye irritation.
54 ENVIRONMENTAL SCIENCES↗